Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CLEANING TABLETS
Field of the Invention
This invention relates to the use of polyalkylene glycols for improving
the moisture stability of cleaning tablets and to certain cleaning tablets
with
improved moisture stability which contain polyalkylene glycols. In the
context of the invention, cleaning tablets include, for example, tablets for
washing laundry, tablets for machine or manual dishwashing or for cleaning
of hard surfaces, bleach tablets for use in washing or dishwashing
machines, water softening tablets, stain remover tablets and lavatory
cleaning tablets.
Background of the Invention
Cleaning tablets of the product classes mentioned are widely
described in the prior art literature and are enjoying increasing popularity
among consumers by virtue of the fact that they are easy to dose.
Tabletted detergents have a number of advantages over powder-form or
liquid products: they are easier to dose and handle and, by virtue of their
compact structure, have advantages in regard to storage and
transportation. Accordingly, there is an extremely broad prior art on the
subject of cleaning tablets which is also reflected in extensive patent
literature.
Lavatory cleaners in tablet form which contain acids and surfactants
are well known. To accelerate the dissolution and distribution of the active
substances in the lavatory bowl, lavatory cleaner tablets preferably contain
sodium carbonate and/or sodium bicarbonate as an effervescent
component.
It is known that corresponding formulations are extremely sensitive
to moisture so that expensive packs impermeable to water vapor and/or
additional drying agents are required to guarantee stability in storage.
EP 0 522 766 A (Unilever) discloses tablets of a compacted
particulate detergent component containing surfactants, builders and
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optionally other detergent ingredients which, in at least one discrete region,
only contain particles at least 200 Nm in size with a size range covering no
more than 700 pm and which contain (i) surfactant and builder particles
coated with a polyethylene glycol having a molecular weight of 1500.
DE 197 09 41 (Henkel KGaA) discloses a process for the production
of detergent tablets containing surfactants, builders and optionally other
detergent ingredients by tabletting a particulate detergent composition, in
which 0.5 to 10% by weight of polyethylene glycol and (ii) 5 to 20% by
weight of an amorphous overdried silicate and (iii) 1 to 15% by weight of
water or aqueous solutions, based on the weight of the tablet formed, are
used to produce the tablets.
EP 0 711 828 A (Unilever) discloses a process for the production of
detergent tablets containing surfactants builders and optionally other
detergent ingredients (iv) by compacting a particulate detergent
composition with a binder distributed therein at a temperature of at least
28°C, but below the melting point of the binder of 35 to 90°C.
The binder
may be selected inter alia from polyethylene glycols, for example poly-
ethylene glycols with a molecular weight of 1,500, 4,000 or 6,000.
However, there is nothing in the prior art to suggest that
polyethylene glycols would be effective in improving the moisture stability of
cleaning tablets.
The problem addressed by the present invention was to improve the
moisture stability of cleaning tablets.
Summary of the Invention
The present invention relates to the use of one or more polyalkylene
glycols for improving the moisture stability of cleaning tablets.
In a second embodiment, the present invention relates to a cleaning
tablet containing one or more polyalkylene glycols, excluding tablets which
contain
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i) surfactant and builder particles coated with a polyethylene glycol having
a molecular weight of 1,500
or which have been produced
ii) using 5 to 20% by weight of an amorphous overdried silicate,
iii) using 1 to 15% by weight of water or aqueous solutions or
iv) by compacting a particulate detergent composition with a binder
distributed therein at a temperature of at least 28°C, but below the
melting point of the binder of 35 to 90°C.
In a third embodiment, the present invention relates to a process for
the production of a cleaning tablet by compacting a particulate detergent
composition with one or more polyalkylene glycols distributed therein at a
temperature below 28°C.
In a fourth embodiment, the present invention relates to a combina-
tion of one or more cleaning tablets containing polyalkylene glycol and a
pack containing the cleaning tablet(s), the pack having a water vapor
transmission rate of 0.1 g/m2/day to less than 20 g/m2/day where it is stored
at 23°C and at a relative equilibrium humidity of 85%.
In a fifth embodiment, the present invention relates to the use of one
or more cleaning tablets according to the invention for cleaning toilets,
descaling, cleaning hard surfaces, manual dishwashing, machine
dishwashing, bleaching, stain removal, washing and/or water softening.
The cleaning tablets are preferably used for cleaning flush toilets, more
particularly in the region of the water standing in the bottom of the lavatory
bowl, for descaling domestic appliances, more particularly coffee machines
and kettles, for cleaning hard surfaces in the home, more particularly floors
and surfaces in kitchens and bathrooms or toilets, for manual dishwashing,
for machine dishwashing, for bleaching, stain removal or washing textile
articles and surfaces, more particularly clothing, table linen, bed linen,
upholstery, curtains and carpets or carpeting and in the interior of
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automobiles and/or for softening water in washing machines.
One particular advantage of the invention is that the improvement in
moisture stability is not achieved at the expense of other properties of the
cleaning tablets, i.e. the other properties are not adversely affected by the
polyalkylene glycols. This is also apparent from the following Examples.
Detailed Description of the Invention
The following description of the invention - unless otherwise
specifically stated - applies to all embodiments of the invention, i.e. for
example both to the use according to the invention and to the cleaning
tablet according to the invention, even if each embodiment of the invention
is not expressly mentioned.
Molecular weights are expressed as "unitless" relative molecular
weights, the molecular weights of polymers, more particularly the molecular
weights of the higher polyalkylene glycols, representing average relative
molecular weights.
Unless otherwise specifically indicated, quantities and contents are
expressed in % by weight, based on the cleaning tablet. In this connection,
variously preferred quantity ranges, such as "preferably 0.1 to 10% by
weight, more preferably 1 to 5% by weight", simultaneously signify
preferred upper and lower limits, i.e. "preferably at least 0.1 % by weight,
more preferably at least 1 % by weight but no more than 10% by weight and
more particularly no more than 5% by weight" and, accordingly, also mean
that the quantity ranges of 0.1 to 5% by weight and 1 to 10% by weight are
preferred to 0.1 to 10% by weight.
Substances which also serve as ingredients of cosmetic
preparations may be referred to in the following by their names under the
/NCI nomenclature (/NCI - Infernational Nomenclature of Cosmetic
Ingredients). Chemical compounds bear an /NCI name in English while
vegetable ingredients are all referred to by their Latin names according to
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Linne, so-called trivial names such as "water", "honey" or "sea salt" also
being shown in Latin. The INCI names can be found in the International
Cosmetic Ingredient Dictionary and Handbook - 7th Edition (1997)
which is published by the Cosmetic, Toiletry and Fragrance Association
5 (CTFA), 1101 17th Street, NW, Suite 300, Washington, DC 20036, USA
and which contains more than 9,000 INCI names and references to more
than 37,000 commercial names and technical names, including the
associated distributors from more than 31 countries. The International
Cosmetic Ingredient Dictionary and Handbook assigns the ingredients to
one or more chemical classes, for example Polymeric Ethers, and one or
more functions, for example Surfactants - Cleansing agents, which in turn
are explained in detail and to which reference may also be made in the
following.
Polyalkylene gl_vcols
Polyalkylene glycols (polyglycols, polyglycol ethers; INCI Chemical
Class: Polymeric Ethers) are known, predominantly linear, but occasionally
branched polyethers which are hydroxy-terminated polymers. The
relatively high molecular weight polyalkylene glycols are polymolecular, i.e.
they consist of "collectives" of macromolecules with various molecular
weights.
According to the invention, polyalkylene glycols are used in a
quantity of normally 0.1 to 20% by weight, preferably 0.5 to 10% by weight,
more preferably 1 to 7% by weight and most preferably 2 to 5% by weight.
The quantity of polyalkylene glycols present in the cleaning tablet is
preferably selected so that it is completely soluble in the quantity of water
taken up by the cleaning tablet - for more than one cleaning tablet to be
taken up by the quantity of water in the corresponding partial quantity of
water. The maximum soluble quantity is determined both by the solubility
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of the polyalkylene glycol in water and by the said quantity or partial
quantity of water which is dependent upon the particular application of the
cleaning tablet. Both values are either known or can be determined by
simple tests.
According to the invention, linear or branched, more particularly
linear, polyalkylene glycols with the following general formula:
HO-[R-O]~ H
in which R represents (CH2)2, CH2CH(CH3) and/or (CH2)4 and n has a
value of 2 to more than 100,000 and which are obtainable by ring-opening
polymerization of ethylene oxide, propylene oxide and/or tetrahydrofuran,
are preferred. More particularly, these polyalkylene glycols are polyethyl-
ene glycols with R = (CH2)2, polypropylene glycols with R = CH2CH(CH3),
polytetrahydrofurans with R = (CH2)4 and copolymers of ethylene oxide,
propylene oxide and/or tetrahydrofuran.
In one preferred embodiment of the invention, preferred polyalkylene
glycols have a melting point above the temperature prevailing during
production of the cleaning tablet, preferably above a room temperature of
about 21 °C, more preferably above 23°C and most preferably at
least
28°C. The melting point of homologous homopolymeric polyalkylene
glycols generally increases with increasing molecular weight and narrowing
molecular weight distribution. In addition, the melting point of copolymeric
polyalkylene glycols generally increases with increasing oxygen content - in
the case of ethylene oxide/propylene oxide copolymers for example,
generally with increasing polyethylene glycol content. Finally, the melting
point of the polypropylene glycols generally increases with increasing
tacticity (stereoregularity).
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Polyethylene glycols
According to the invention, polyethylene glycols (PEGs) with an
average relative molecular weight of 800 to 100,000, normally 1,000 to
80,000, preferably 1,500 to 70,000 and more preferably 2,000 to 60,000
are suitable.
Low molecular weight PEGs with molecular weights below 800 are
clear, substantially colorless liquids and are therefore less suitable for the
purposes of the invention. Beyond a molecular weight of about 800, PEGs
become partly crystalline solids. With increasing molecular weight, PEGs
change first into soft waxes at molecular weights of about 1,000 to 2,000
and then into hard waxes at molecular weights of up to about 20,000 and
higher. Finally, high molecular weight PEGs with molecular weights above
100,000 are hard thermoplastics and, accordingly, are unsuitable for the
purposes of the invention.
One particularly advantageous embodiment of the present invention
is characterized by the use of one or more polyethylene glycols with a
molecular weight of at least 3,000, preferably in the range from 4,000 to
50,000, more preferably in the range from 6,000 to 40,000, most preferably
in the range from 8,000 to 30,000 and, in one most particularly preferred
embodiment, in the range from 10,000 to 20,000. Cleaning tablets
according to this embodiment are particularly moisture-stable, their
moisture stability being significantly improved by comparison with cleaning
tablets containing polyethylene glycol with a molecular weight of less than
3,000.
There are various nomenclatures for polyethylene glycols which can
lead to confusion. Technically, it is standard practice to show the average
relative molecular weight after the initials "PEG", so that "PEG 200"
characterizes a polyethylene glycol having a relative molecular weight of
ca. 190 to ca. 210.
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Under the INCI nomenclature, the initials PEG are followed by a
hyphen which in turn is directly followed by a number which corresponds to
the number n in the above general formula, the three zeros "000" in
multiples of 1,000 being replaced by the letter "M" so that, for example,
PEG-7M stands for a PEG having an average n value of 7,000.
Commercially obtainable polyethylene glycols with a molecular
weight below 3,000 are, for example, PEG 800/PEG-18, PEG-20, PEG
1000, PEG 1200, PEG 1500/PEG-32, PEG-40, PEG 2000, PEG-55 and
PEG-60, the names under the two nomenclatures for corresponding
polyethylene glycols being separated from one another by the symbol "/".
Commercially obtainable polyethylene glycols with a molecular
weight of 3,000 to 88,000 are, for example, PEG 3000, PEG 3350/PEG-75,
PEG 4000/PEG-90, PEG 4500/PEG-100, PEG 4600, PEG 6000/PEG-135,
PEG 7000, PEG-150, PEG 8000/PEG-180, PEG 9000/PEG-200, PEG
10000/PEG-240, PEG 12000, PEG 14000, PEG 15000/PEG-350, PEG-
400, PEG 20000, PEG 35000, PEG 50000 and PEG-2M, the names under
the two nomenclatures for corresponding polyethylene glycols being
separated from one another by the symbol "/".
The commercially obtainable polyethylene glycols are available, for
example, under the names of Carbowax~ 8000 (Union Carbide),
Emkapol~ 6000 and Renex~ PEG 3350 (ICI), Lipoxol~ (DEA), Polyglykol~
E 4500 (Dow), Pluracol~ E8000, Puriol~ E12000 and Lutrol~ E4000
(BASF) and the corresponding trade names with other numbers which
represent the molecular weights of the polyethylene glycol. Reference
sources for the polyethylene glycols with INCI names also serving as
cosmetic ingredients can be found in the International Cosmetic Ingredient
Dictionary and Handbook. The Clariant organization also markets poly-
ethylene glycols, for example PEG 10000 to PEG 35000.
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Polypropylene glycols
Polypropylene glycols (PPGs) are clear, substantially colorless
liquids or amorphous or crystalline solids covering a broad molecular
weight range, the liquids being less suitable for the purposes of the present
invention. The INCI nomenclature mentioned above is also used analo-
gously for naming polypropylene glycols.
Liquid viscous polypropylene glycols usually have molecular weights
of 250 (PPG-4) to 4,000 (PPG-69); low molecular weight representatives
are miscible with water while relatively high molecular weight PPGs are
poorly soluble in water. The polypropylene glycols are formed by ring
opening polymerization of propylene oxide. They can be produced as
amorphous or stereoregular polymers, tacticity (stereoregularity) leading to
the preferred crystalline PPGs.
According to the invention, the molecular weights of the
polypropylene glycols are normally in the range from ca. 2,000 to 100,000,
preferably in the range from 4,000 to 50,000, more preferably in the range
from 6,000 to 40,000, most preferably in the range from 8,000 to 30,000
and, in one most particularly preferred embodiment, in the range from
10,000 to 20,000.
Polypropylene glycols are usually obtainable as di- and trihydroxy
PPGs in a broad range of molecular weights. The third hydroxy group
emanates from the polymerization initiator where glycerol, for example, is
used as initiator for polypropylene glycols of which the three hydroxy
groups react in the polymerization and thus lead to branched trihydroxy
PPGs.
Polytetrahydrofurans
The polytetrahydrofurans (PTHFs) are also known as tetramethylene
glycols, polytetramethylene glycol ethers or polytetramethylene oxides and
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are polyalkylene ethers obtainable by cationic polymerization (ring opening
polymerization) of tetrahydrofuran at temperatures below 83°C.
PTHFs are strictly linear polyether diols which are industrially
produced using fuming nitric acid or fluorosulfuric acid as catalysts.
5 According to the invention, the molecular weights of the PTHFs, which can
reach values of up to several million, are normally in the range from about
650 to 100,000, preferably in the range from 1,000 to 50,000, more
preferably in the range from 1,400 to 30,000, most preferably in the range
from 2,900 to 20,000 and, in one most particularly preferred embodiment,
10 in the range from 4,500 to 10,000.
PTHFs are liquids or low-melting, normally crystalline solids at room
temperature. The consistency of PTHFs increases with increasing
molecular weight from oily through wax-like to solid. Amorphous PTHFs
with molecular weights above 100,000 are rubber-like products. Partly
crystalline PTHFs melt at around 43°C. Low molecular weight PTHFs are
soluble in water.
Polytetrahydrofurans with molecular weights of 650, 1,000, 1,400,
2,000, 2,900 and 4,500, for example, are commercially obtainable. The
commercially obtainable polytetrahydrofurans are available, for example,
under the names of Polytetrahydrofuran 650 or PoIyTHF~ 4500 (BASF),
Terathane~ 2900 and Teracol~ 1000 (Du Pont) and Polymeg~ 2000
(Quaker Oats) and the corresponding trade names with other numbers
which represent the molecular weights of the polyethylene glycol.
Copolymers
The copolymers are preferably statistical copolymers and, more
particularly, block copolymers of ethylene and propylene oxide, ethylene
oxide and tetrahydrofuran, propylene oxide and tetrahydrofuran or ethylene
oxide, propylene oxide and tetrahydrofuran, preferably block copolymers of
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ethylene and propylene oxide and more preferably block copolymers of
ethylene and propylene oxide. According to the invention, the molecular
weights of the copolymers are normally in the range from about 2,000 to
100,000, preferably in the range from 3,000 to 50,000, more preferably in
the range from 4,000 to 40,000, most preferably in the range from 6,000 to
30,000 and, in one most particularly preferred embodiment, in the range
from 8,000 to 20,000.
According to the invention, preferred statistical copolymers of a
ethylene and b propylene oxide units are, for example, the following
copolymers (molecular weight) named as PEG/PPG-a/b according to the
International Cosmetic Ingredient Dictionary and Handbook, a and b
representing mean values: PEG/PPG-125/30 Copolymer (7300),
PEG/PPG-150/30 Copolymer (8400) and PEG/PPG-300/55 Copolymer
(16400).
According to the invention, preferred block copolymers of ethylene
and propylene oxide correspond to the formula
HO(CH2CH20)x(CH(CH3)CH20)y(CH2CH20)X~H, in which x and x' stand for
mean values of 2 to 130 while z stands for mean values of 15 to 67, and
are referred to by the International non-proprietary name of poloxamer
which is also used in the International Cosmetic Ingredient Dictionary and
Handbook. Every poloxamer is characterized by a three-digit number. The
first two digits multiplied by 100 indicate the average molecular weight of
the polypropylene glycol component while the last digit multiplied by 10
indicates the polyethylene glycol content in % by weight which is between
10 and 80% by weight, preferably at least 30% by weight, more preferably
at least 40% by weight, most preferably at least 50% by weight and, in one
most particularly preferred embodiment, at least 60% by weight, for
example 70 or 80% by weight. The poloxamers are produced in two
stages, propylene oxide being added under control onto propylene glycol in
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the first stage and the polypropylene glycol block obtained being enclosed
by two polyethylene glycol blocks by subsequent addition of ethylene
oxide.
Particularly preferred block copolymers are, for example, the
following poloxamer types (x, y, x'; molecular weight; in some cases
melting point): poloxamer 185 (19, 30, 19; 3500; 27), poloxamer 215 (24,
35, 24; 4150; 34), poloxamer 234 (22, 39, 22; 4200), poloxamer 284 (21,
47, 21; 4600), poloxamer 235 (27, 29, 27; 4650; 29), poloxamer 333 (20,
54, 20; 4900; 30), poloxamer 108 (46, 16, 46; 4950; 48), poloxamer 402
(13, 67, 13; 5000; 20), poloxamer 403 (21, 67, 21; 5750; 31 ), poloxamer
334 (31, 54, 31; 5900; 32), poloxamer 335 (38, 54, 38; 6500; 30),
poloxamer 217 (52, 35, 52; 6600; 48), poloxamer 237 (62, 39, 62; 7700;
49), poloxamer 188 (75, 30, 75; 8350; 52), poloxamer 238 (97, 39, 97;
11400; 54), poloxamer 407 (98, 67, 98; 12600; 56), poloxamer 288 (122,
47, 122; 13000; 58) and poloxamer 338 (128, 54, 128; 14600; 57).
The poloxamers are commercially obtainable under the names of
Pluronic~ and Synperonic~ PE followed by the letter L, P or F and a two-
digit or three-digit number. The last digit is identical with the last digit
of the
poloxamer nomenclature and the preceding single- or two-digit numbers
multiplied by 300 indicate the approximate molecular weight of the
polypropylene glycol component and, multiplied by 3, approximately the
number formed from the first two digits of the poloxamer nomenclature
number, i.e. 3, 4, 6, 7, 8, 9, 10 and 12 correspond in that order to the 2-
digit
numbers 10, 12, 18, 21, 23, 28, 33 and 40 at the beginning of the number
under the poloxamer nomenclature. The letters distinguish between liquid
(L), paste-form (P) and solid (F) poloxamers. Thus, poloxamer 238, for
example, is obtainable as Pluronic~ F 88 and Synperonic ~ PE F 88.
Another class of suitable block copolymers of ethylene and
propylene oxide correspond to the formula
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HO(CH(CH3)CH20)y(CH2CH20)X(CH2CH(CH3)O)y~H. Here, one
polyethylene glycol block is enclosed by two polypropylene glycol blocks
whereas, in the case of the poloxamers, one polypropylene glycol block is
enclosed by two polyethylene glycol blocks. Production is again carried out
in two stages, ethylene oxide being added under control onto ethylene
glycol in the first stage and the polyethylene glycol block obtained being
enclosed by two polypropylene glycol blocks by subsequent addition of
propylene oxide.
These block copolymers like the poloxamers are commercially
obtainable under the name of Pluronic~ (BASS followed by an alpha-
numeric code of three digits and the letter R between the second and third
digits. The meaning of the digits is identical with their meaning under the
poloxamer nomenclature. The letter R (reverse) between the second and
third digits indicates the inverted structure compared with the poloxamers.
Preferred representatives of this class are the following Pluronic~ types
(molecular weight; melting point): Pluronic~ 1784 (2650; 18), Pluronic~
2284 (3350; 24), Pluronic~ 2584 (3600; 25), Pluronic~ 31 R4 (4150; 24),
Pluronic~ 2585 (4250; 30), Pluronic~ 1088 (4550; 46), Pluronic~ 1788
(7000; 53), Pluronic~ 2588 (8550; 54).
Other ingredients
Besides the polyalkylene glycols crucial to the invention, the
cleaning tablets contain one or more other ingredients typical of detergents
or rather cleaning tablets. The nature and quantity of the other
ingredients) is/are determined in the usual way by the application
envisaged for the cleaning tablet.
The other ingredients perform one or more primary functions and/or
one or more secondary functions. The primary functions are concerned
with the actual cleaning or washing effect of the cleaning tablet and its in-
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use handling behavior, for example its disintegration properties. The
secondary functions are concerned with the production of the cleaning
tablet and its handling behavior in production, for example its fracture
resistance. Other ingredients with secondary functions are also known as
tabletting aids or tablet auxiliaries. A clear division into other ingredients
with a purely primary function and those with a purely secondary function is
not always possible because primary and secondary functions are often
fulfilled at the same time. More particularly, the other ingredients with
secondary functions may optionally combine several properties.
Other ingredients of importance by virtue of their primary function
are disintegration aids, surfactants, bleaching agents and builders and also
corrosion inhibitors, soil release compounds, enzymes, soil repellents,
optical brighteners, dyes and perfumes and antimicrobial agents. Other
ingredients of importance by virtue of their secondary function are fillers,
separating agents or lubricants, binders and powdering materials. These
other ingredients are described in the following.
The expert will have no difficulty in selecting the individual
components and their quantities acording to the application envisaged for
the cleaning tablets. For example, a heavy-duty detergent tablet will
contain relatively large quantities of surfactants) whereas a bleaching
tablet may even contain no surfactant at all.
Disintegration aids
In order to facilitate the disintegration of heavily cleaning compacted
tablets, disintegration aids, so-called tablet disintegrators, may be
incorporated in them to shorten their disintegration times. According to
Rompp (9th Edition, Vol. 6, page 4440) and Voigt "Lehrbuch der
pharmazeutischen Technologie" (6th Edition, 1987, pages 182-184),
tablet disintegrators or disintegration accelerators are auxiliaries which
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promote the rapid disintegration of tablets in water or gastric juices and the
release of the pharmaceuticals in an absorbable form.
These substances, which are also known as "disintegrators" by
virtue of their effect, are capable of undergoing an increase in volume on
5 contact with water so that, on the one hand, their own volume is increased
(swelling) and, on the other hand, a pressure can be generated through the
release of gases which causes the tablet to disintegrate into relatively small
particles. So-called "effervescent systems" are also often used as
disintegration-promoting systems in cleaning tablets. Well-known effer-
10 vescent systems are carbonate/citric acid systems. Swelling disintegration
aids are, for example, synthetic polymers, such as polyvinyl pyrrolidone
(PVP), or natural polymers and modified natural substances, such as cel-
lulose and starch and derivatives thereof, alginates or casein derivatives.
15 Effervescent systems
An effervescent system consists of a combination of two or more
substances which release a gas, such as carbon dioxide or oxygen, on
contact with water. Preferred effervescent systems consist of one or more
acidic components and one or more carbon dioxide sources.
Suitable acidic components are, for example, organic acids, more
particularly oligocarboxylic acids optionally containing hydroxy groups, such
as the di- and tricarboxylic acids, for example succinic acid, oleic acid,
glutaric acid, adipic acid, tartaric acid and, more particularly, citric acid,
and
acidic salts of polybasic inorganic or organic acids, for example potassium
dihydrogen phosphate or sodium hydrogen sulfate, and amidosulfuric acid
(H2N S02 OH; formerly: amidosulfonic acid, sulfamic acid). Particularly
suitable C02-releasing components are the salts of carbonic acid, i.e.
carbonates and hydrogen carbonates and mixtures thereof which are used,
above all, as alkali metal and alkaline earth metal salts.
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Particularly preferred acidic components are amidosulfuric acid,
citric acid and sodium hydrogen sulfate and mixtures thereof. Preferred
mixtures consist of amidosulfuric acid and citric acid, preferably in a ratio
by
weight of amidosulfuric acid to citric acid of 100:1 to 1:100, more
particularly 50:1 to 1:20, more preferably 20:1 to 1:10 and most preferably
13:1 to 10:1 or 2:1 to 1:2, for example 12:1 or 11:1 or 1:1. The mixtures of
amidosulfuric acid and citric acid are preferably used as the sole acidic
component of the effervescent system, although they may also be
combined with sodium hydrogen carbonate and/or one or more other acid
components.
Particularly preferred C02 components are sodium carbonate (soda)
and sodium hydrogen carbonate (sodium bicarbonate) and mixtures of
sodium carbonate and sodium hydrogen carbonate, more particularly
sodium carbonate and mixtures of sodium carbonate and sodium hydrogen
carbonate. Mixtures of sodium carbonate and sodium hydrogen carbonate
normally have a ratio by weight of sodium hydrogen carbonate to sodium
carbonate of 20:1 to 1:10, more particularly 10:1 to 1:1, more preferably 5:1
to 3:1 and most preferably 5:1 to 4:1, for example 3.6:1, 4.4:1 or 4.6:1.
The higher the hydrogen carbonate content of the C02 component
and/or the content of an acid or C02 component or effervescent system as
a whole, the more vigorously the effervescent system effervesces or foams
and the more quickly the cleaning tablets usually decompose.
The choice of the content of acid and C02 components) also has to
take into account the pH value which is supposed to be established in the
use of the cleaning tablets. Thus, descaling tablets or lavatory cleaner
tablets normally contain an excess of acid in order to guarantee sufficient
acidity for the cleaning effect. For a tablet suitable for manual dishwashing,
for example, a 10% by weight aqueous solution of the cleaning tablet may
advantageously have a pH value below 7 and, more particularly, in the
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range from 3 to 6. By contrast, an excess of C02 component may be
selected, for example, for a multipurpose cleaning tablet in order to enable
an alkaline cleaning solution sufficient for the desired cleaning effect to be
obtained through dissolution of the cleaning tablet (for example a pH in the
range from 8 to 11 ).
The cleaning tablet contains an effervescent system in a quantity of
normally 1 to 99.9% by weight, preferably 10 to 99% by weight and more
preferably 20 to 98% by weight. The moisture-stabilizing effect of the
alkylene polyglycols according to the invention is particularly advantageous
in effervescent and, more particularly, highly effervescent cleaning tablets.
In one preferred embodiment of the invention, the cleaning tablet
contains an effervescent system in a quantity of at least 50% by weight,
preferably at least 60% by weight, more preferably 70 to 97% by weight,
most preferably 80 to 96% by weight and, in one most particularly preferred
embodiment, 85 to 95% by weight. Cleaning tablets corresponding to this
preferred embodiment contain large amounts of acid and C02 component
and/or an excess of acid or C02 component and are therefore suitable for
applications where vigorous effervescence or foaming and/or high acidity or
alkalinity is required, more particularly as cleaning tablets for flush
toilets
(lavatory cleaner tablets) for the acidic cleaning of flush toilets and as
descaling tablets (descaler tablet) for acidic descaling.
A cleaning tablet suitable for use as a manual dishwashing
detergent may contain the effervescent system in a quantity of, for
example, 20 to 70% by weight, preferably 25 to 60% by weight and more
preferably 28 to 55% by weight.
In embodiments of the present invention particularly suitable as
laundry detergents and/or machine dishwashing detergents, however, the
cleaning tablet is not an "effervescent tablet", i.e. is free from acid or C02
components, preferably free from acids, more particularly free from
CA 02315137 2000-08-04
18
oligomeric oligocarboxylic acids and more preferably free from citric acid.
Swelling disintegration aids
Instead of or in addition to an effervescent system, the cleaning
tablets may contain one or more swelling disintegration aids, normally in a
quantity of 0.5 to 10% by weight, preferably in a quantity of 3 to 7% by
weight and more preferably in a quantity of 4 to 6% by weight.
According to the invention, preferred swelling disintegrators are
cellulose-based disintegrators, so that preferred detergent tablets contain a
cellulose-based disintegrator in quantities of 0.5 to 10% by weight,
preferably 3 to 7% by weight and more preferably 4 to 6% by weight. Pure
cellulose has the formal empirical composition (C6H~pO5)n and, formally, is
a ~-1,4-polyacetal of cellobiose which, in turn, is made up of two molecules
of glucose. Suitable celluloses consist of ca. 500 to 5000 glucose units
and, accordingly, have average molecular weights of 50,000 to 500,000.
According to the invention, cellulose derivatives obtainable from cellulose
by polymer-analog reactions may also be used as cellulose-based
disintegrators. These chemically modified celluloses include, for example,
products of esterification or etherification reactions in which hydroxy
hydrogen atoms have been substituted. However, celluloses in which the
hydroxy groups have been replaced by functional groups that are not
attached by an oxygen atom may also be used as cellulose derivatives.
The group of cellulose derivatives includes, for example, alkali metal
celluloses, carboxymethyl cellulose (CMC), cellulose esters and ethers and
aminocelluloses.
The cellulose derivatives mentioned are preferably not used on their
own, but rather in the form of a mixture with cellulose as cellulose-based
disintegrators. The content of cellulose derivatives in mixtures such as
these is preferably below 50% by weight and more preferably below 20%
CA 02315137 2000-08-04
19
by weight, based on the cellulose-based disintegrator. In one particularly
preferred embodiment, pure cellulose free from cellulose derivatives is
used as the cellulose-based disintegrator.
The cellulose used as disintegration aid is preferably not used in
fine-particle form, but is converted into a coarser form, for example by
granulation or compacting, before it is added to and mixed with the
premixes to be tabletted. Detergent tablets which contain granular or
optionally co-granulated disintegrators are described in German patent
applications DE 197 09 991 (Stefan Herzog) and DE 197 10 254 (Henkel)
and in International patent application WO 98140463 (Henkel). Further
particulars of the production of granulated, compacted or co-granulated
cellulose disintegrators can also be found in these patent applications. The
particle sizes of such disintegration aids are mostly above 200 Nm,
preferably at least 90% by weight of the particles being between 300 and
1600 pm in size and, more particularly, between 400 and 1200 Nm in size.
According to the invention, the above-described relatively coarse-particle
cellulose-based disintegrators described in detail in the cited patent
applications are preferably used as disintegration aids and are
commercially obtainable, for example under the name of Arbocel~ TF-30-
HG from Rettenmaier.
Microcrystalline cellulose may be used as another cellulose-based
disintegration aid or as part of such a component. This microcrystalline
cellulose is obtained by partial hydrolysis of celluloses under conditions
which only attack and completely dissolve the amorphous regions (ca. 30%
of the total cellulose mass) of the celluloses, but leave the crystalline
regions (ca. 70%) undamaged. Subsequent de-aggregation of the
microfine celluloses formed by hydrolysis provides the microcrystalline
celluloses which have primary particle sizes of ca. 5 Nm and which can be
compacted, for example, to granules with a mean particle size of 200 Nm.
CA 02315137 2000-08-04
In one particular embodiment of the present invention particularly
suitable as laundry and/or dishwasher detergents, preferred cleaning
tablets contain one or more disintegration aids, preferably a swelling
disintegration aid, more particularly based on cellulose, preferably in
5 granular, cogranulated or compacted form, in quatities of 0.5 to 10% by
weight, preferably in quantities of 3 to 7% by weight and more preferably in
quantities of 4 to 6% by weight, based on tablet weight.
Surfactants
10 Preferred cleaning tablets additionally contain one or more
surfactants.
To develop their cleaning performance, the cleaning tablets
according to the invention may contain surface-active compounds from the
group of anionic, nonionic, zwitterionic and cationic surfactants, anionic
15 surfactants being distinctly preferred for economic reasons and for their
performance spectrum.
The surfactant content of manual dishwashing tablets is normally
between 10 and 40% by weight, preferably between 12.5 and 30% by
weight and more preferably between 15 and 25% by weight whereas
20 machine dishwashing tablets normally contain between 0.1 and 10% by
weight, preferably between 0.5 and 7.5% by weight and more preferably
between 1 and 5% by weight. Tablets for cleaning hard surfaces
(multipurpose cleaning tablets) may have the above-mentioned surfactant
contents of up to and over 10% by weight, depending on their formulation.
Lavatory cleaning tablets usually contain up to 5% by weight of surfactants,
preferably from 0.1 to 3% by weight, more preferably from 0.3 to 2% by
weight and most preferably from 0.5 to 1 % by weight. Bleach tablets and
water softening tablets are normally free from surfactants.
CA 02315137 2000-08-04
21
Anionic sun'actants
Suitable anionic surfactants are, for example, those of the sulfonate
and sulfate type. Suitable surfactants of the sulfonate type are preferably
C9_~3 alkyl benzenesulfonates, olefin sulfonates, i.e. mixtures of alkene and
hydroxyalkane sulfonates, and the disulfonates obtained, for example, from
C~2_~8 monoolefins with an internal or terminal double bond by sulfonation
with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of
the sulfonation products. Other suitable surfactants of the sulfonate type
are the alkane sulfonates obtained from C~2_~8 alkanes, for example by
sulfochlorination or sulfoxidation and subsequent hydrolysis or neutral-
ization. The esters of a-sulfofatty acids (ester sulfonates), for example the
a-sulfonated methyl esters of hydrogenated coconut, palm kernel or tallow
fatty acids, are also suitable.
Other suitable anionic surfactants are sulfonated fatty acid glycerol
esters. Fatty acid glycerol esters in the context of the present invention are
the monoesters, diesters and triesters and mixtures thereof which are
obtained where production is carried out by esterification of a monoglycerol
with 1 to 3 moles of fatty acid or in the transesterification of triglycerides
with 0.3 to 2 moles of glycerol. Preferred sulfonated fatty acid glycerol
esters are the sulfonation products of saturated fatty acids containing 6 to
22 carbon atoms, for example caproic acid, caprylic acid, capric acid,
myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid.
Preferred alk(en)yl sulfates are the alkali metal salts and, in
particular, the sodium salts of the sulfuric acid semiesters of C~2_~$ fatty
alcohols, for example coconut alcohol, tallow alcohol, lauryl, myristyl, cetyl
or stearyl alcohol, or C~o_2o oxoalcohols and the corresponding semiesters
of secondary alcohols with the same chain length. Other preferred
alk(en)yl sulfates are those with the chain length mentioned which contain
a synthetic, linear alkyl chain based on a petrochemical and which are
CA 02315137 2000-08-04
22
similar in their degradation behavior to the corresponding compounds
based on oleochemical raw materials. C~2_~s alkyl sulfates, C~z_~5 alkyl
sulfates and C~a_~5 alkyl sulfates are preferred from the point of view of
washing technology. Other suitable anionic surfactants are 2,3-alkyl
sulfates which may be produced, for example, in accordance with US
3,234,258 or US 5,075,041 and which are commerially obtainable as
products of the Shell Oil Company under the name of DAN~.
The sulfuric acid monoesters of linear or branched C~_2~ alcohols
ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl-branched
1O Cg_~~ alcohols containing on average 3.5 moles of ethylene oxide (EO) or
C~2_~g fatty alcohols containing 1 to 4 EO, are also suitable. In view of
their
high foaming capacity, they are only used in relatively small quantities, for
example in quantities of not more than 5% by weight, in dishwashing
detergents.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic
acid which are also known as sulfosuccinates or as sulfosuccinic acid
esters and which represent monoesters and/or diesters of sulfosuccinic
acid with alcohols, preferably fatty alcohols and, more particularly,
ethoxylated fatty alcohols. Preferred sulfosuccinates contain C$_~$ fatty
alcohol residues or mixtures thereof. Particularly preferred sulfosuccinates
contain a fatty alcohol residue derived from ethoxylated fatty alcohols
which, considered in isolation, represent nonionic surfactants (for a
description, see below). Of these sulfosuccinates, those of which the fatty
alcohol residues are derived from narrow-range ethoxylated fatty alcohols
are particularly preferred. Alk(en)yl succinic acid preferably containing 8 to
18 carbon atoms in the alk(en)yl chain or salts thereof may also be used.
Other suitable anionic surfactants are, in particular, soaps. Suitable
soaps are saturated fatty acid soaps, such as the salts of lauric acid,
myristic acid, palmitic acid, stearic acid, hydrogenated erucic acid and
CA 02315137 2000-08-04
23
behenic acid, and soap mixtures derived in particular from natural fatty
acids, for example coconut oil, palm kernel oil or tallow fatty acids.
The anionic surfactants, including the soaps, may be present in the
form of their sodium, potassium or ammonium salts and as soluble salts of
organic bases, such as mono-, di- or triethanolamine. The anionic
surfactants are preferably present in the form of their sodium or potassium
salts and, more preferably, in the form of their sodium salts.
Cleaning tablets according to the invention in the form of laundry
detergent or manual dishwashing detergent tablets preferably contain
anionic surfactants) in quantities of 5 to 50% by weight, preferably in
quantities of 7.5 to 40% by weight and more preferably in quantities of 10
to 20% by weight, based on the weight of the tablet.
So far as the choice of the anionic surfactants used in the cleaning
tablets according to the invention is concerned, there are no basic
requirements to restrict freedom of formulation. Preferred anionic
surfactants are the alkyl benzenesulfonates, alkyl sulfates and fatty alcohol
sulfates, preferred cleaning tablets in the form of laundry detergent tablets
containing 2 to 20% by weight, preferably 2.5 to 15% by weight and more
preferably 5 to 10% by weight of fatty alcohol sulfate(s), based on the
weight of the tablet.
Nonionic surfactants
Preferred nonionic surfactants are alkoxylated, advantageously
ethoxylated, more especially primary alcohols preferably containing 8 to 18
carbon atoms and, on average, 1 to 12 moles of ethylene oxide (EO) per
mole of alcohol, in which the alcohol radical may be linear or, preferably,
methyl-branched in the 2-position or may contain linear and methyl-
branched radicals in the form of the mixtures typically present in oxoalcohol
radicals. However, alcohol ethoxylates containing linear radicals of
CA 02315137 2000-08-04
24
alcohols of native origin with 12 to 18 carbon atoms, for example coconut
oil, palm oil, tallow or oleyl alcohol, and on average 2 to 8 EO per mole of
alcohol are particularly preferred. Preferred ethoxylated alcohols include,
for example, 02_14 alcohols containing 3 EO or 4 EO, C9_~~ alcohol
containing 7 EO, C~3_~5 alcohols containing 3 EO, 5 EO, 7 EO or 8 EO,
C~2_~$ alcohols containing 3 EO, 5 EO or 7 EO and mixtures thereof, such
as mixtures of C~2_~4 alcohol containing 3 EO and C~2_~$ alcohol containing
5 EO. The degrees of ethoxylation mentioned represent statistical mean
values which, for a special product, can be a whole number or a broken
number. Preferred alcohol ethoxylates have a narrow homolog distribution
(narrow range ethoxylates, NRE). In addition to these nonionic surfactants,
fatty alcohols containing more than 12 EO may also be used, examples
including tallow fatty alcohol containing 14 EO, 25 EO, 30 EO or 40 EO.
Another class of preferred nonionic surfactants which may be used
either as sole nonionic surfactant or in combination with other nonionic
surfactants are alkoxylated, preferably ethoxylated or ethoxylated and
propoxylated, fatty acid alkyl esters preferably containing 1 to 4 carbon
atoms in the alkyl chain, more especially the fatty acid methyl esters which
are described, for example, in Japanese patent application JP 58/217598
or which are preferably produced by the process described in International
patent application WO-A-90/13533.
Another class of nonionic surfactants which may advantageously be
used are the alkyl polyglycosides (APGs). Suitable alkyl polyglycosides
correspond to the general formula RO(G)Z where R is a linear or branched,
more particularly 2-methyl-branched, saturated or unsaturated aliphatic
radical containing 8 to 22 and preferably 12 to 18 carbon atoms and G
stands for a glycose unit containing 5 or 6 carbon atoms, preferably
glucose. The degree of glycosidation z is between 1.0 and 4.0, preferably
between 1.0 and 2.0 and more preferably between 1.1 and 1.4.
CA 02315137 2000-08-04
Linear alkyl polyglucosides, i.e. alkyl polyglycosides in which the
polyglycosyl moiety is a glucose unit and the alkyl moiety is an n-alkyl
group, are preferably used.
The cleaning tablets according to the invention may advantageously
5 contain alkyl polyglycosides, APG contents in the tablets of more than 0.2%
by weight, based on the tablet as a whole, being preferred. Particularly
preferred cleaning tablets contain APGs in quantities of 0.2 to 10% by
weight, preferably in quantities of 0.2 to 5% by weight and more preferably
in quantities of 0.5 to 3% by weight.
10 Nonionic surfactants of the amine oxide type, for example N-
cocoalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxyethyl-
amine oxide, and the fatty acid alkanolamide type are also suitable. The
quantity in which these nonionic surfactants are used is preferably no more
than the quantity in which the ethoxylated fatty alcohols are used and,
15 more preferably, no more than half that quantity.
Other suitable surfactants are polyhydroxyfatty acid amides
corresponding to formula (I):
R~
R-CO-N-[Z] (I )
in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms,
R' is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon
atoms and [Z] is a linear or branched polyhydroxyalkyl group containing 3
to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid
amides are known substances which may normally be obtained by
reductive amination of a reducing sugar with ammonia, an alkylamine or an
alkanolamine and subsequent acylation with a fatty acid, a fatty acid alkyl
ester or a fatty acid chloride.
The group of polyhydroxyfatty acid amides also includes compounds
CA 02315137 2000-08-04
26
corresponding to formula (II):
R~-O-R2
R-CO-N-[Z] (II)
in which R is a linear or branched alkyl or alkenyl group containing 7 to 12
carbon atoms, R' is a linear, branched or cyclic alkyl group or an aryl group
containing 2 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl
group or an aryl group or an oxyalkyl group containing 1 to 8 carbon atoms,
C~_4 alkyl or phenyl groups being preferred, and [Z] is a linear polyhydroxy-
alkyl group, of which the alkyl chain is substituted by at least two hydroxyl
groups, or alkoxylated, preferably ethoxylated or propoxylated, derivatives
of that group.
[Z] is preferably obtained by reductive amination of a reduced sugar,
for example glucose, fructose, maltose, lactose, galactose, mannose or
xylose. The N-alkoxy- or N-aryloxy-substituted compounds may then be
converted into the required polyhydroxyfatty acid amides by reaction with
fatty acid methyl esters in the presence of an alkoxide as catalyst, for
example in accordance with the teaching of International patent application
WO-A-95107331.
According to the invention, preferred cleaning tablets are those
containing anionic and nonionic surfactant(s). Performance-related
advantages can arise out of certain quantity ratios in which the individual
classes of surfactants are used.
For example, particularly preferred cleaning tablets are charac-
terized in that the ratio of anionic surfactants) to nonionic surfactants) is
from 10:1 to 1:10, preferably from 7.5:1 to 1:5 and more preferably from 5:1
to 1:2.
It can be of advantage from the performance point of view if certain
classes of surfactants are missing from certain phases of the cleaning
CA 02315137 2000-08-04
27
tablets or from the entire tablet, i.e. from every phase. In another important
embodiment of the present invention, therefore, at least one phase of the
cleaning tablets is free from nonionic surfactants.
Conversely, a positive effect can also be obtained through the
presence of certain surfactants in individual phases or in the cleaning tablet
as a whole, i.e. in every phase. Introducing the alkyl polyglycosides
described above has proved to be of particular advantage, so that cleaning
tablets in which at least one phase of the tablet contains alkyl
polyglycosides are preferred.
As with the nonionic surfactants, the omission of anionic surfactants
from individual phases or from all phases can result in cleaning tablets
which are more suitable for certain applications. Accordingly, cleaning
tablets where at least one phase of the tablet is free from anionic
surfactants are also possible in accordance with the present invention.
B il r
Besides detersive ingredients, builders are iportant ingredients of
detergents and cleaners, especially multipurpose cleaners, dishwasher
detergents and laundry detergents. The cleaning tablets according to the
invention may contain any of the builders typically used in detergents and
cleaners, i.e. in particular zeolites, silicates, carbonates/hydrogen
carbonates, organic cobuilders and - providing there are no ecological
objections to their use - also the phosphates. The builders mentioned may
also be used in surfactant-free cleaning tablets so that it is possible in
accordance with the invention to produce cleaning tablets which may be
used for softening water or as bleach tablets.
Suitable crystalline layered sodium silicates correspond to the
general formula NaMSiXO~+~y H20, where M is sodium or hydrogen, x is a
number of 1.9 to 4 and y is a number of 0 to 20, preferred values for x
CA 02315137 2000-08-04
28
being 2, 3 or 4. Crystalline layered silicates such as these are described,
for example, in European patent application EP-A-0 164 514. Preferred
crystalline layered silicates corresponding to the above formula are those in
which M is sodium and x assumes the value 2 or 3. Both ~3- and 8-sodium
disilicates Na2Si205y H20 are particularly preferred, ~-sodium disilicate
being obtainable, for example, by the process described in International
patent application WO-A- 91108171.
Other useful builders are amorphous sodium silicates with a
modulus (Na20:Si02 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more
preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash
cycle properties. The delay in dissolution in relation to conventional
amorphous sodium silicates can have been obtained in various ways, for
example by surface treatment, compounding, compacting or by overdrying.
In the context of the invention, the term "amorphous" is also understood to
encompass "X-ray amorphous". In other words, the silicates do not
produce any of the sharp X-ray reflexes typical of crystalline substances in
X-ray diffraction experiments, but at best one or more maxima of the
scattered X-radiation which have a width of several degrees of the
diffraction angle. However, particularly good builder properties may even
be achieved where the silicate particles produce crooked or even sharp
diffraction maxima in electron diffraction experiments. This may be
interpreted to mean that the products have microcrystalline regions
between 10 and a few hundred nm in size, values of up to at most 50 nm
and, more particularly, up to at most 20 nm being preferred. So-called X-
ray amorphous silicates such as these, which also dissolve with delay in
relation to conventional waterglasses, are described for example in
German patent application DE-A-44 00 024. Compacted amorphous
silicates, compounded amorphous silicates and overdried X-ray-amorphous
silicates are particularly preferred.
CA 02315137 2000-08-04
29
The finely crystalline, synthetic zeolite containing bound water used
in accordance with the invention is preferably zeolite A and/or zeolite P.
Zeolite MAP~ (Crosfield) is a particularly preferred P-type zeolite.
However, zeolite X and mixtures of A, X and/or P are also suitable.
According to the invention, it is preferred to use, for example, a
commercially obtainable co-crystallizate of zeolite X and zeolite A (ca. 80%
by weight zeolite X) which is marketed by CONDEA Augusta S.p.A. under
the name of VEGOBOND AX~ and which may be described by the
following formula:
nNa20 ~ (1-n)K20 ~ A1203 ~ (2 - 2.5)Si02 ~ (3.5 - 5.5) H20.
The zeolite may be used both as a builder in a granular compound and for
"powdering" the entire mixture to be tabletted, both these options normally
being used to incorporate the zeolite in the premix. Suitable zeolites have
a mean particle size of less than 10 ~m (volume distribution, as measured
by the Coulter Counter Method) and contain preferably 18 to 22% by
weight and more preferably 20 to 22% by weight of bound water.
As already mentioned, the generally known phosphates may of
course also be used as builders providing their use should not be avoided
on ecological grounds. The sodium salts of the orthophosphates, the
pyrophosphates and especially the tripolyphosphates, more particularly the
pentasodium triphosphate known as sodium tripolyphosphate, are
particularly suitable.
Useful organic builders are, for example, the polycarboxylic acids
usable, for example, in the form of their sodium salts, such as citric acid,
adipic acid, succinic acid, glutaric acid, tartaric acid, benzene
hexacarboxylic acid, sugar acids, for example gluconic acid, amino-
carboxylic acids, nitrilotriacetic acid (NTA), providing its use is not
CA 02315137 2000-08-04
ecologically unsafe, and mixtures thereof. Preferred salts are the salts of
the polycarboxylic acids, such as citric acid, adipic acid, succinic acid,
glutaric acid, tartaric acid, sugar acids and mixtures thereof.
The quantity of builder, particularly in the absence of an effervescent
5 system, is normally between 10 and 70% by weight, preferably between 15
and 60% by weight and more preferably betwween 20 and 50% by weight.
The quantity of builders used in again dependent on the application
envisaged so that bleach tablets may contain larger quantities of builders
(for example between 20 and 70% by weight, preferably between 25 and
10 65% by weight and more preferably between 30 and 55% by weight) than,
for example, laundry detergent tablets (normally 10 to 50% by weight,
preferably 12.5 to 45% by weight and more preferably between 17.5 and
37.5% by weight).
Since builders, such as the carbonates and hydrogen carbonates
15 and a number of carboxylic acids, can also serve as components of an
effervescent system, the quantities mentioned above should not be
understood as cumulative in the presence of an effervescent system. If,
therefore, the cleaning tablet contains an effervescent system, the quantity
of builders additionally present is normally only up to 20% by weight,
20 preferably from 0.01 to 15% by weight, more preferably from 0.1 to 10% by
weight and most preferably from 0.3 to 8% by weight, for example 6% by
weight, or no additional builder at all is present.
Bleaching agents
25 Among the compounds yielding H202 in water which serve as
bleaching agents, sodium perborate tetrahydrate and sodium perborate
monohydrate are particularly important. Other useful bleaching agents are,
for example, sodium percarbonate, peroxypyrophosphates, citrate perhy-
drates and H202-yielding peracidic salts or peracids, such as
CA 02315137 2000-08-04
31
perbenzoates, peroxophthalates, diperazelaic acid, phthaloiminoperacid or
diperdodecane dioic acid. Where bleaching agents are used, it is again
possible to leave out surfactants and/or builders so that pure bleach tablets
can be produced. If such bleach tablets are to be used for washing
laundry, a combination of sodium percarbonate with sodium
sesquicarbonate is preferably used, irrespective of what other ingredients
the cleaning tablets contain. If tablets for dishwashing machines are being
produced, bleaching agents from the group of organic bleaches may also
be used. Typical organic bleaching agents are diacyl peroxides, such as
dibenzoyl peroxide for example. Other typical organic bleaching agents are
the peroxy acids, of which alkyl peroxy acids and aryl peroxy acids are
particularly mentioned as examples. Preferred representatives are (a)
peroxybenzoic acid and ring-substituted derivatives thereof, such as alkyl
peroxybenzoic acids, but also peroxy-a-naphthoic acid and magnesium
monoperphthalate, (b) aliphatic or substituted aliphatic peroxy acids, such
as peroxylauric acid, peroxystearic acid, s-phthalimidoperoxycaproic acid
[phthaloiminoperoxyhexanoic acid (PAP)], o-carboxybenzamidoperoxy-
caproic acid, N-nonenylamidoperadipic acid and N-nonenylamido-
persuccinates and (c) aliphatic and araliphatic peroxydicarboxylic acids,
such as 1,12-diperoxycarboxylic acid, 1,9-diperoxyazelaic acid, diperoxy-
sebacic acid, diperoxybrassylic acid, diperoxyphthalic acids, 2-decyldi-
peroxybutane-1,4-dioic acid, N,N-terephthaloyl-di(6-aminopercaproic acid).
Preferred cleaning tablets according to the invention contain at least
one oxygen bleaching agent from the group consisting of alkali metal
perborates, alkali metal percarbonates, organic per acids and hydrogen
peroxide, more especially from the group consisting of alkali metal
perborates and alkali metal percarbonates, more preferably sodium
perborate and/or sodium percarbonate.
The cleaning tablets according to the invention contain one or more
CA 02315137 2000-08-04
32
bleaching agents in a quantity of normally 0 to 50% by weight, preferably
0.1 to 30% by weight and more preferably 1 to 15% by weight. Bleach
tablets, such as stain remover tablet, naturally contain large amounts of
bleaching agents whereas laundry, dishwasher detergent tablets contain
medium amounts of bleaching agent and cleaning tablets, such as lavatory
cleaner tablets, generally contain only small amounts of bleaching agent of
up to 5% by weight, for example 1 or 2% by weight, or no bleaching agent
at all.
Other suitable bleaching agents, particularly in dishwasher tablets
and cleaner tablets, are chlorine- or bromine-releasing substances.
Suitable chlorine- or bromine-releasing materials are, for example,
heterocyclic N-bromamides and N-chloramides, for example
trichloroisocyanuric acid, tribromoisocyanuric acid, dibromoisocyanuric acid
and/or dichloroisocyanuric acid (DICA) and/or salts thereof with cations,
such as potassium and sodium. Hydantoin compounds, such as 1,3-
dichloro-5,5-dimethyl hydantoin, are also suitable as are hypochlorites and
other typical chlorine-containing bleaching agents.
In order to obtain an improved bleaching effect where cleaning or
washing is carried out at temperatures of 60°C or lower, bleach
activators
may be incorporated. The bleach activators may be compounds which
form aliphatic peroxocarboxylic acids containing preferably 1 to 10 carbon
atoms and more preferably 2 to 4 carbon atoms and/or optionally
substituted perbenzoic acid under perhydrolysis conditions. Substances
bearing O- and/or N-acyl groups with the number of carbon atoms
mentioned and/or optionally substituted benzoyl groups are suitable.
Preferred bleach activators are polyacylated alkylenediamines, more
particularly tetraacetyl ethylenediamine (TAED), acylated triazine
derivatives, more particularly 1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine
(DADHT), acylated glycolurils, more particularly tetraacetyl glycoluril
CA 02315137 2000-08-04
33
(TAGU), N-acylimides, more particularly N-nonanoyl succinimide (NOSI),
acylated phenol sulfonates, more particularly n-nonanoyl or
isononanoyloxybenzenesulfonate (n- or iso-NOBS), carboxylic anhydrides,
more particularly phthalic anhydride, acylated polyhydric alcohols, more
particularly triacetin, ethylene glycol diacetate and 2,5-diacetoxy-2,5-
dihydrofuran.
In addition to or instead of the conventional bleach activators
mentioned above, so-called bleach catalysts may also be incorporated in
the cleanng tablets. Bleach catalysts are bleach-boosting transition metal
salts or transition metal complexes such as, for example, manganese-,
iron-, cobalt-, ruthenium- or molybdenum-salen complexes or carbonyl
complexes. Manganese, iron, cobalt, ruthenium, molybdenum, titanium,
vanadium and copper complexes with nitrogen-containing tripod ligands
and cobalt-, iron-, copper- and ruthenium-ammine complexes may also be
used as bleach catalysts.
The bleaching performance of bleach-containing cleaning tablets,
such as laundry detergent tablets, cleaner tablets or bleach tablets, is
preferably increased by the use of bleach activators. Thus, in one
particular embodiment, cleaning tablets according to the invention contian
at least one bleach activator, preferably from the group of polyacylated
alkylenediamines, more particularly tetraacetyl ethylenediamine (TAED), N-
acyl imides, more particularly N-nonanoyl succinimide (NOSI), acylated
phenol sulfonates, more particularly n-nonanoyl or
isononanoyloxybenzenesulfonate (n- or iso-NOBS), n-methyl morpholinium
acetonitrile methyl sulfate (MMA) and/or bleach-boosting transition metal
complexes, more particularly containing the central atoms Mn, Fe, Co, Cu,
Mo, V, Ti and/or Ru, preferably selected from the group of manganese
and/or cobalt salts and/or complexes, more preferably the cobalt (ammine)
complexes, cobalt (acetate) complexes, cobalt (carbonyl) complexes,
CA 02315137 2000-08-04
34
chlorides of cobalt or manganese and manganese sulfate.
The cleaning tablets according to the invention may contain, for
example between 0.5 and 30% by weight, preferably betwween 1 and 20%
by weight and more preferably between 2 and 15% by weight, based on
the tablet as a whole, of one or more bleach activators or bleach catalysts.
These quantities may vary according to the application envisaged for the
cleaning tablets. Thus, in typical heavy-duty detergent tablets, bleach
activator contents of 0.5 to 10% by weight, preferably between 2 and 8%
by weight and more preferably between 0.5 and 10% by weight are normal
whereas bleach tablets contain much larger amounts, for example between
5 and 30% by weight, preferably between 7.5 and 25% by weight and more
preferably between 10 and 20% by weight. The expert is not restricted in
his freedom of formulation and can thus produce laundry detergent tablets,
cleaner tablets or bleach tablets with a relatively strong or weak bleaching
effect by varying the contents of bleach activator and bleaching agent.
A particularly preferred bleach activator is N,N,N',N'-tetraacetyl
ethylenediamine which is widely used in detergents. Accordingly, preferred
cleaning tablets are characterized in that tetraacetyl ethylenediamine in the
quantities mentioned above is used as bleach activator.
Corrosion inhibitors
To protect the tableware or the machine itself, dishwashing tablets
according to the invention may contain corrosion inhibitors, silver protectors
being particularly important for dishwashing machines. Above all, silver
protectors selected from the group of triazoles, benzotriazoles,
bisbenzotriazoles, aminotriazoles, alkylaminotriazoles and the transition
metal salts or complexes may generally be used. Benzotriazole and/or
alkylaminotriazole is/are particularly preferred. In addition, dishwashing
formulations often contain corrosion inhibitors containing active chlorine
CA 02315137 2000-08-04
which are capable of distinctly reducing the corrosion of silver surfaces.
Chlorine-free dishwashing detergents contain in particular oxygen- and
nitrogen-containing organic redox-active compounds, such as dihydric and
trihydric phenols, for example hydroquinone, pyrocatechol, hydroxy-
5 hydroquinone, gallic acid, phloroglucinol, pyrogallol and derivatives of
these compounds. Salt-like and complex-like inorganic compounds, such
as salts of the metals Mn, Ti, Zr, Hf, V, Co and Ce are also frequently used.
Of these, the transition metal salts selected from the group of manganese
and/or cobalt salts and/or complexes are preferred, cobalt(ammine)
10 complexes, cobalt(acetate) complexes, cobalt(carbonyl) complexes,
chlorides of cobalt or manganese and manganese sulfate being particularly
preferred. Zinc compounds may also be used to prevent corrosion of
tableware.
15 Soil-release corn ou~nds
Particular ingredients which may be used in cleaning tablets
according to the invention for machine dishwashing or for the cleaning of
hard surfaces are substances which prevent the resoiling of surfaces
and/or facilitate the release of soil after a single application ( so-called
soil-
20 release compounds).
Suitable soil-release compounds are any of the compounds known
from the prior art. Particularly suitable soil-release compounds are cationic
polymers such as, for example, hydroxypropyl trimethyl ammonium guar;
copolymers of aminoethyl methacrylate and acrylamide and copolymers of
25 dimethyl diallyl ammonium chlorider and acrylamide, polymers containing
imino groups, cationic cellulose derivatives, cationic homo- and/or
copolymers (monomer units: quaternized ammonium alkyl methacrylate
groups).
Particularly preferred soil-release compunds are the cationic
CA 02315137 2000-08-04
36
polymers selected from cationic polymers of copolymers of such monomers
as trialkyl ammonium alkyl (meth)acrylate or acrylamide; dialkyl diallyl
diammonium salts; polymer-analog reaction products of ethers or esters of
polysaccharides with lateral ammonium groups, more particularly guar, cel-
lulose and starch derivatives; polyadducts of ethylene oxide with ammon-
ium groups; quaternary ethylene imine polymers and polyesters and poly-
amides containing quaternary lateral groups as soil-release compounds.
Natural polyuronic acids and related substances and also polyampholytes
and hydrophobicized polyampholytes and mixtures of these substances are
also particularly preferred for the purposes of the present invention.
Enzxmes
Suitable enzymes are those from the class of proteases, lipases,
amylases, cellulases or mixtures thereof. Enzymes obtained from bacterial
strains or fungi, such as Bacillus subtilis, Bacillus licheniformis and
Streptomyces griseus, are particularly suitable. Proteases of the subtilisin
type are preferred, proteases obtained from Bacillus lentus being
particularly preferred. Enzyme mixtures, for example of protease and
amylase or protease and lipase or protease and cellulase or of cellulase
and lipase or of protease, amylase and lipase or of protease, lipase and
cellulase, but especially cellulase-containing mixtures, are of particular
interest. Peroxidases or oxidases have also proved to be suitable in some
cases. The enzymes may be adsorbed to supports and/or encapsulated in
membrane materials to protect them against premature decomposition.
The percentage content of the enzymes, enzyme mixtures or enzyme
granules in the cleaning tablets according to the invention, more particularly
in laundry and dishwashing detergent tablets may be, for example, from
about 0.1 to 5% by weight and is preferably from 0.1 to about 2% by
weight.
CA 02315137 2000-08-04
37
The most commonly used enzymes include lipases, amylases,
cellulases and proteases. Preferred proteases are, for example, BLAP~
140 (Biozym), Optimase~ M-440 and Opticlean~ M-250 (Solvay
Enzymes); Maxacal~ CX and Maxapem~ or Esperase~ (Gist Brocades)
and even Savinase~ (Novo). Particularly suitable cellulases and lipases
are Celluzym~ 0,7 T and Lipolase~ 30 T (Novo Nordisk). Particularly
suitable amylases are Duramyl~ and Termamyl~ 60 T and Termamyl~ 90
T (Novo), Amylase-LT~ (Solvay Enzymes) and Maxamyl~ P5000 (Gist
Brocades). Other enzymes may also be used.
Soil repellents
In addition, the cleaning tablets according to the invention, more
particularly laundry detergent and stain remover tablets, may also contain
components with a positive effect on the removal of oil and fats from
textiles by washing (so-called soil repellents). This effect becomes
particularly clear when a textile which has already been repeatedly washed
with a detergent according to the invention containing this oil- and fat-
dissolving component is soiled. Preferred oil- and fat-dissolving
components include, for example, nonionic cellulose ethers, such as methyl
cellulose and methyl hydroxypropyl cellulose containing 15 to 30% by
weight of methoxyl groups and 1 to 15% by weight of hydroxypropoxyl
groups, based on the nonionic cellulose ether, and the polymers of phthalic
acid and/or terephthalic acid known from the prior art or derivatives thereof,
more particularly polymers of ethylene terephthalates and/or polyethylene
glycol terephthalates or anionically and/or nonionically modified derivatives
thereof. Of these, the sulfonated derivatives of phthalic acid and
terephthalic acid polymers are particularly preferred.
- CA 02315137 2000-08-04
38
Qptical brighteners
The cleaning tablets, more particularly laundry detergent tablets,
may contain derivatives of diaminostilbenedisulfonic acid or alkali metal
salts thereof as optical brighteners. Suitable optical brighteners are, for
example, salts of 4,4'-bis-(2-anilino-4-morpholino-1,3,5-triazinyl-6-amino)-
stilbene-2,2'-disulfonic acid or compounds of similar composition which
contain a diethanolamino group, a methylamino group, an anilino group or
a 2-methoxyethylamino group instead of the morpholino group.
Brighteners of the substituted diphenyl styryl type, for example alkali metal
salts of 4,4'-bis-(2-sulfostyryl)-diphenyl, 4,4'-bis-(4-chloro-3-sulfostyryl)-
diphenyl or 4-(4-chlorostyryl)-4'-(2-sulfostyryl)-diphenyl, may also be
present. Mixtures of the brighteners mentioned above may also be used.
The optical brighteners are used in the cleaning tablets according to
the invention, more particularly laundry detergent tablets, in concentrations
of 0.01 tot % by weight, preferably in concentrations of 0.05 to 0.5% by
weight and more preferably in concentrations of 0.1 to 0.25% by weight,
based on the tablet as a whole.
Dves and perfumes
Dyes and perfumes are added to the cleaning tablets according to
the invention to improve the aesthetic impression created by the products
and to provide the consumer not only with the required washing
performance but also with a visually and sensorially "typical and
unmistakable" product. Suitable perfume oils or fragrances include
individual perfume compounds, for example synthetic products of the ester,
ether, aldehyde, ketone, alcohol and hydrocarbon type. Perfume
compounds of the ester type are, for example, benzyl acetate,
phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate,
dimethyl benzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate,
CA 02315137 2000-08-04
39
benzyl formate, ethyl methyl phenyl glycinate, allyl cyclohexyl propionate,
styrallyl propionate and benzyl salicylate. The ethers include, for example,
benzyl ethyl ether; the aldehydes include, for example, the linear alkanals
containing 8 to 18 carbon atoms, citral, citronellal, citronellyloxy-
acetaldehyde, cyclamen aldehyde, hydroxycitronellal, lilial and bourgeonal;
the ketones include, for example, the ionones, a-isomethyl ionone and
methyl cedryl ketone; the alcohols include anethol, citronellol, eugenol,
geraniol, linalool, phenyl ethyl alcohol and terpineol and the hydrocarbons
include, above all, the terpenes, such as limonene and pinene. However,
mixtures of various perfumes which together produce an attractive perfume
note are preferably used. Perfume oils such as these may also contain
natural pefume mixtures obtainable from vegetable sources, for example
pine, citrus, jasmine, patchouli, rose or ylang-ylang oil. Also suitable are
clary oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leaf oil,
lime
blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanum oil and
labdanum oil and orange blossom oil, neroli oil, orange peel oil and
sandalwood oil.
The dye content is normally below 0.1 % by weight and, more
particularly, below 0.05% by weight while perfumes may make up as much
as 2% by weight and more particularly from 0.1 to 0.5% by weight of the
formulation as a whole.
The perfumes may be directly incorporated in the tablets, although it
can also be of advantage to apply the perfumes to supports which
strengthen the adherence of the perfume to the washing and which provide
the textiles with a long-lasting fragrance through a slower release of the
perfume. Suitable support materials are, for example, cyclodextrins, the
cyclodextrin/perfume complexes optionally being coated with other
auxiliaries.
In order to improve their aesthetic impression, the cleaning tablets
CA 02315137 2000-08-04
according to the invention may be colored with suitable dyes. Preferred
dyes, which are not difficult for the expert to choose, have high stability in
storage, are not affected by the other ingredients of the tablets or by light
and do not have any pronounced substantivity for the treated substrates,
5 for example textile fibers or tableware, so as not to color them.
Any dyes which can be destroyed by oxidation in the washing
process and mixtures thereof with suitable blue dyes, so-called blueing
agents, are preferably used in the cleaning tablets according to the
invention. It has proved to be of advantage to use dyes which are soluble
10 in water or - at room temperature - in liquid organic substances. Suitable
dyes are, for example, anionic dyes, for example anionic nitroso dyes. One
possible dye is, for example, naphthol green (Color Index (CI) Part 1: Acid
Green 1; Part 2: 10020), which is commercially available for example as
Basacid~ Grun 970 from BASF, Ludwigshafen, and mixtures thereof with
15 suitable blue dyes. Other suitable dyes are Pigmosol~ Blau 6900 (CI
74160), Pigmosol~ Grun 8730 (CI 74260), Basonyl~ Rot 545 FL (CI
45170), Sandolan~ Rhodamin EB 400 (CI 45100), Basacid~ Gelb 094 (CI
47005), Sicovit~ Patentblau 85 E 131 (CI 42051 ), Acid Blue 183 (CAS
12217-22-0, CI Acid Blue 183), Pigment Blue 15 (CI 74160), Supranol~
20 Blau GLW (CAS 12219-32-8, CI Acid Blue 221 ), Nylosan~ Gelb N-7GL
SGR (CAS 61814-57-1, CI Acid Yellow 218) and/or Sandolan~ Blau (CI
Acid Blue 182, CAS 12219-26-0).
In selecting the dye for cleaning tablets for the treatment of textile
surfaces, more particularly for laundry detergent and stain remover tablets,
25 it is important to ensure that the dye does not have an excessive affinity
for
the textile surfaces and, in particular, for synthetic fibers. Another factor
to
be taken into account in the selection of suitable dyes is that dyes differ in
their stability to oxidation. Generally speaking, water-insoluble dyes are
more stable to oxidation than water-soluble dyes. The concentration of the
CA 02315137 2000-08-04
41
dye in the detergents varies according to its solubility and hence its
sensitivity to oxidation. In the case of readily water-soluble dyes, for
example the above-mentioned Basacid~ Grun and Sandolan~ Blau, dye
concentrations in the range from a few 10-2 to 10'3 % by weight are typically
selected. By contrast, in the case of the pigment dyes which are
particularly preferred for their brilliance, but which are less readily
soluble in
water, for example the above-mentioned Pigmosol~ dyes, suitable
concentrations of the dye in cleaners or laundry detergents are typically of
the order of a few 10'3 to 10'4 % by weight.
Antimicrobial agents
In order to provide the cleaning tablets according to the invention
with antimicrobial activity or merely to preserve them, one or more
antimicrobial agents may be present, preferably being selected from the
groups of alcohols, aldehydes, antimicrobial acids, carboxylic acid esters,
acid amides, phenols, phenol derivatives, diphenyls, diphenyl alkanes, urea
derivatives, oxygen acetals and formats, nitrogen acetals and formats,
benzamidines, substituted isothiazoles and hydrogenated isothiazole
derivatives, such as isothiazolines (dihydroisothiazoles) and
isothiazolidines, phthalimide derivatives, pyridine derivatives, antimicrobial
surface-active compounds, such as antimicrobial quaternary surface-active
compounds, guanidines, antimicrobial amphoteric compounds, quinolines,
1,2-dibromo-2,4-dicyanobutane, iodo-2-propynyl butyl carbamate, iodine,
iodophores and peroxides, for example phenoxyethanol, undecylenic acid,
salicylic acid, benzoic acid, , 2-benzyl-4-chlorophenol, 2,2'-methylene-bis-
(6-bromo-4-chlorophenol), 2,4,4'-trichloro-2'-hydroxydiphenyl ether, N-(4-
chlorophenyl)-N-(3,4-dichlorophenyl)-urea, N,N'-(1,10-decanediyldi-1-
pyridinyl-4-ylidene)-bis-(1-octanamine)-dihydrochloride and N,N'-bis-(4-
chlorophenyl)-3,12-diimino-2,4,11,13-tetraazatetradecane diimidoamide, as
CA 02315137 2000-08-04
42
described, for example in K.H. Wallhau~er "Praxis der Sterilisation,
Desinfektion - Konservierung : Keimidentifizierung - Betriebshygiene"
(5th Edition, Stuttgart/New York: Thieme, 1995).
The cleaning tablets according to the invention preferably contain
salicylic acid and/or isothiazolines as their antimicrobial component.
The content of one or more antimicrobial agents is normally between
0 and 10% by weight, preferably between 0.001 and 5% by weight, more
preferably between 0.01 and 2% by weight, most preferably between 0.05
and 1 % by weight and, in one most particularly preferred embodiment,
between 0.1 and 0.5% by weight.
Fillers
Fillers (extenders, INCI Bulking Agents) are - generally relatively
inexpensive - often chemically inert solids which are added to increase
volume and/or weight or to dilute the other solids and, in many cases, also
to improve usability. Fillers are also used to adjust the form in which a
product is to be marketed and/or its concentration.
Suitable fillers are carbonates, more particularly calcium carbonate,
and also silicates (talcum, clay, mica), silica, calcium and barium sulfate,
aluminium hydroxide and cellulose powders or microcrystalline cellulose
and lactose, sucrose, mannitol and sorbitol and also starch and dicalcium
phosphate.
A particularly preferred filler is sodium sulfate. Fillers, such as
sodium sulfate, also act as an auxiliary for improving processability in
production and flow behavior, for preventing lump formation and dust
emission, as a carrier and for correcting powder properties.
Other suitable fillers are, for example, the following fillers referred to
by their INCI names which are described in more detail in International
Cosmetic Ingredient Dictionary and Handbook: Alumina, Aluminum Silicate,
CA 02315137 2000-08-04
43
Amylodextrin, Attapulgite, Barley (Hordeum Distichon) Flour, Barley
(Hordeum Vulgare) Flour, Bentonite, Betaglucan, Biotite, Calcium
Aluminum Borosilicate, Calcium Carbonate, Calcium Caseinate, Calcium
Phosphate, Calcium Silicate, Calcium Sodium Borosilicate, Calcium
Sulfate, Cellulose, Chalk, Chitin, Coconut (Cocos Nucifera) Shell Powder,
Colloidal Oatmeal, Corn (Zea Mays) Cob Meal, Corn (Zea Mays) Flour,
Corn (Zea Mays) Gluten Protein, Corn (Zea Mays) Meal, Croscarmellose,
Dextran, Dextrin, Diatomaceous Earth, Fuller's Earth, Hectorite, Hydrated
Silica, Hydroxyapatite, Hydroxypropyl Starch Phosphate, Isomalt, Kaolin,
Lithium Magnesium Silicate, Lithium Magnesium Sodium Silicate, Loess,
Magnesium Carbonate, Magnesium Carbonate Hydroxide, Magnesium
Silicate, Magnesium Stearate, Magnesium Sulfate, Magnesium Tallowate,
Magnesium Trisilicate, Microcrystalline Cellulose, Microcrystalline Wax,
Montmorillonite, Moroccan Lava Clay, Nylon-6, Nylon-11, Nylon-12, Nylon-
66, Oat (Avena Sativa) Bran, Oat (Avena Sativa) Flour, Oat (Avena Sativa)
Meal, Peach (Prunus Persica) Pit Powder, Peanut (Arachis Hypogaea)
Flour, Pecan (Carya Illinoensis) Shell Powder, Perlite, Polydextrose,
Polyethylene, Polyoxymethylene Melamine Urea, Polyoxymethylene Urea,
Polypropylene, Potato (Solanum Tuberosum) Starch, PTFE, Pumice,
Rayon, Rice (Oryza Sativa) Bran, Rice (Oryza Sativa) Starch, Rye (Secale
Cereale) Flour, Silica, Silica Dimethyl Silylate, Silica Silylate, Silk, Silk
Powder, Sodium Hydroxypropyl Starch Phosphate, Sodium Magnesium
Silicate, Soybean Flour (Glycine Soja), Sweet Almond (Prunus Amygdalus
Dulcis) Meal, Talc, Tin Oxide, Titanium Hydroxide, Trimagnesium
Phosphate, Walnut (Juglans Mandshurica) Shell Powder, Walnut (Juglans
Regia) Shell Powder, Wheat (Triticum Vulgare) Bran, Wheat (Triticum
Vulgare) Flour, Wheat (Triticum Vulgare) Powder, Wheat (Triticum Vulgare)
Starch, Wood Powder, Zinc Borosilicate and Zinc Oxide.
- CA 02315137 2000-08-04
44
Bin r
Binders (dry binders, INCI Binders) impart adhesive properties
during and after the tabletting of a particulate premix to form cleaning
tablets according to the invention. Many liquids, surfactants and polymers
may be used as binders. In selecting the binder, it is important to ensure
that the effect of the disintegration aid is not adversely influenced.
Suitable binders are, for example, lactose, sucrose, mannitol,
sorbitol, microcrystalline cellulose, starch, dicalcium phosphate, starch,
alginates, polyvinyl pyrrolidone (PVP) and carboxymethyl cellulose.
Binders particularly suitable for granulation are starch, alginates, polyvinyl
pyrrolidone and, more particularly, carboxymethyl cellulose.
A particularly preferred binder is polyvinyl pyrrolidone (PVP).
Other suitable binders are, for example, the following binders
referred to by their INCI names which are described in more detail in
International Cosmetic Ingredient Dictionary and Handbook:
Acrylamide/Ammonium Acrylate Copolymer, Acrylamide/Sodium Acrylate
Copolymer, Acrylates/Acrylamide Copolymer, Acrylates/Ammonium
Methacrylate Copolymer, Acrylates Copolymer, Acrylates/Dimethicone
Copolymer, Acrylates/Dimethylaminoethyl Methacrylate Copolymer,
Acrylates/PVP Copolymer, Acrylates/VA Copolymer, Acrylic
Acid/Acrylonitrogens Copolymer, Agar, Algin, Alginic Acid, Ammonium
Acrylates/Acrylonitrogens Copolymer, Ammonium Acrylates Copolymer,
Ammonium Alginate, Ammonium VA/Acrylates Copolymer, Amylopectin,
Beeswax, Behenyl Alcohol, Butylated PVP, Butyl Ester of Ethylene/MA
Copolymer, Butyl Ester of PVM/MA Copolymer, Calcium Caseinate, C1-5
Alkyl Galactomannan, Carboxymethyl Hydroxyethylcellulose,
Carboxymethyl Hydroxypropyl Guar, Cellulose Acetate Propionate
Carboxylate, Cellulose Gum, Ceresin, Collodion, Corn (Zea Mays) Flour,
Croscarmellose, Dextran, Dextran Sulfate, Dextrin, Dibutylhexyl IPDI,
- CA 02315137 2000-08-04
Didecyltetradecyl IPDI, Diglycereth-7 Malate, Dilinoleic
Acid/Ethylenediamine Copolymer, Dioctyldecyl IPDI, Dioctyldodecyl IPDI,
Dioctyl IPDI, Distarch Glyceryl Ether, Distarch Phosphate, Ethylcellulose,
Ethylene/Acrylic Acid Copolymer, Ethylene/Acrylic Acid/VA Copolymer,
5 Ethylene/Calcium Acrylate Copolymer, Ethylene/MA Copolymer,
Ethylene/Magnesium Acrylate Copolymer, Ethylene/Sodium Acrylate
Copolymer, Ethylene/VA Copolymer, Ethyl Ester of PVM/MA Copolymer,
Gelatin, Glyceryl Starch, Guar (Cyanopsis Tetragonoloba) Gum,
Hydroabietyl Alcohol, Hydrogenated Japan Wax, Hydrogenated Jojoba
10 Wax, Hydrogenated Microcrystalline Wax, Hydrogenated Rice Bran Wax,
Hydrogenated Rosin, Hydroxybutyl Methylcellulose, Hydroxyethylcellulose,
Hydroxyethyl Ethylcellulose, Hydroxylated Lanolin, Hydroxypropylcellulose,
Hydroxypropyl Guar, Hydroxypropyl Methylcellulose, Isopropyl Ester of
PVM/MA Copolymer, Isopropylidenediphenol Bishydroxypropyl PEG-180,
15 Isopropyl Isostearate, Isopropyl Lanolate, Isopropyl Laurate, Isopropyl
Linoleate, Isopropyl Myristate, Isopropyl Oleate, Isopropyl Palmitate,
Isopropyl Stearate, Isopropyl Tallowate, Isostearic Acid, Isostearyl
Isostearate, Isostearyl Myristate, Isostearyl Neopentanoate, Isostearyl
Palmitate, Japan (Rhus Succedanea) Wax, Karaya (Sterculia Urens) Gum,
20 Lanolin Alcohol, Lanolin Wax, Lithium Magnesium Silicate, Lithium
Stearate, Locust Bean (Ceratonia Siliqua) Gum, Maltodextrin, Mannitol,
Methoxypolyoxymethylene Melamine, Methylcellulose, Methyl
Ethylcellulose, Microcrystalline Wax, Montan Acid Wax, Montan Wax,
Oleostearine, Ouricury Wax, Ozokerite, Pectin, PEG-5M, PEG-7M, PEG-
25 9M, PEG-14M, PEG-20M, PEG-23M, PEG-25M, PEG-45M, PEG-90M,
PEG-115M, PEG-160M, PEG-100/IPDI Copolymer, Pentaerythrityl
Tetraabietate, Pentaerythrityl Tetrabehenate, Pentaerythrityl
Tetrabenzoate, Pentaerythrityl Tetracocoate, Pentaerythrityl
Tetraisostearate, Pentaerythrityl Tetralaurate, Pentaerythrityl
CA 02315137 2000-08-04
46
Tetraoctanoate, Pentaerythrityl Tetraoleate, Pentaerythrityl
Tetrapelargonate, Pentaerythrityl Tetrastearate, Pentaerythrityl Trioleate,
Piperylene/Butene/Pentene Copolymer, Polyacrylamide, Polyacrylic Acid,
Polybutene, Polybutyl Acrylate, Polydipentene, Polyethylacrylate,
Polyethylene, Polyisobutene, Polyurethane-1, Polyvinyl Acetate, Polyvinyl
Alcohol, Polyvinyl Butyral, Polyvinyl Laurate, Polyvinyl Methyl Ether,
Potassium Alginate, Potassium Aluminum Polyacrylate, Potassium
Carrageenan, Potato (Solanum Tuberosum) Starch, PPG-6-Sorbeth-245,
PPG-6-Sorbeth-500, Propylene Glycol Alginate, PVM/MA Copolymer, PVP,
PVP/Decene Copolymer, PVP/Dimethylaminoethylmethacrylate
Copolymer, PVP/Eicosene Copolymer, PVP/Hexadecene Copolymer,
PVPNA Copolymer, PVPNA/Itaconic Acid Copolymer, Rosin, Shellac,
Shellac Wax, Sodium AcrylateNinyl Alcohol Copolymer, Sodium Acrylates
Copolymer, Sodium Acrylates/Acrolein Copolymer, Sodium
Acrylates/Acrylonitrogens Copolymer, Sodium Carboxymethyl Betaglucan,
Sodium Carboxymethyl Dextran, Sodium Carboxymethyl Starch, Sodium
Carrageenan, Sodium Cellulose Sulfate, Sodium C4-12 Olefin/Maleic Acid
Copolymer, Sodium Magnesium Silicate, Sodium Polyacrylate Starch,
Sodium Polymethacrylate, Styrene/MA Copolymer, Synthetic Beeswax,
Synthetic Candelilla Wax, Synthetic Carnauba, Synthetic Japan Wax,
Synthetic Wax, Tragacanth (Astragalus Gummifer) Gum,
Triethoxycaprylylsilane, Trimethoxycaprylylsilane, VA/Crotonates
Copolymer, Wheat (Triticum Vulgare) Gluten, Wheat (Triticum Vulgare)
Starch and Xanthan Gum.
Dust binding agents
Particular binding agents are dust binding agents which are used to
prevent dust emission during and after tabletting of the particulate premix to
form cleaning tablets according to the invention.
CA 02315137 2000-08-04
47
Preferred dust binding agents are silicone oils and, more particularly,
paraffin oils. One or more dust binding agents, more particularly one or
more paraffin oils, are used in quantities of normally not more than 3% by
weight, preferably from 0.02 to 1 % by weight and more preferably from 0.1
to 1 % by weight.
Release agents
Silicon dioxide
Release agents are solid or liquid substances which reduce the
adhesion forces between two adjoining surfaces (for example molding/
mold), i.e. prevent them from sticking by forming a readily removable film
between the two surfaces (abhesive agent). General properties of release
agents are chemical inertness, favorable spreading behavior and a melting
point adapted to the particular processing method. Release agents are
used in the form of dispersions (emulsions or suspensions), sprays, pastes,
powders and permanent, generally baked-on films. The films can be
produced by spraying on, spread coating or immersion of the mold. An
exception are the so-called internal release agents which are mixed into the
material to be demolded and which are either capable of accumulating on
the surface of the molding or promote fairly rapid curing of the surface so
that no bond is established between the wall of the mold and the molding.
The most important classes of release agents are silicones in the
form of oils, oil emulsions in water, fats and resins, waxes (largely natural
and synthetic paraffins with and without functional groups), metal soaps
(metal salts of fatty acids, such as calcium, lead, magnesium, aluminium,
zinc stearate), fats, polymers (polyvinyl alcohol, polyesters and
polyolefins),
fluorocarbons, inorganic release agents in the form of powders (such as
silicon dioxide, graphite, talcum and mica).
Preferred release agents are the metal soaps and paraffin oils.
CA 02315137 2000-08-04
48
Release agents are used as mold release agents in the
pharmaceutical industry in the production of tablets and dragees (where
the stearates and talcum used also act as lubricants).
Release agents are also known by such special names as abhesive
agents, lubricants and flow aids.
Lubricants
Lubricants are additives for filled plastic compounds (molding
compounds) which are used to make the fillers slide more easily and,
hence, the molding compounds easier to mold. Metal soaps and siloxane
combinations are suitable for this purpose. Known lubricants are metal
soaps, wax and paraffin dispersions, sulfated oils and PE waxes, silicone
oils, paraffin oils.
Suitable lubricants are, for example, starch, talcum and silicon
dioxide.
Flow aids
Flow aids are any auxiliaries which are added to powder-form or
granulated, more particularly hygroscopic, substances in small quantities to
prevent them from forming lumps or agglomerating and thus permanently
to guarantee free flow. They are sometimes referred to as fluidifiers.
Suitable flow aids, which are also known as abhesives, anticaking agents
and fluidifiers, are water-insoluble hydrophobicizing or moisture-adsorbing
powders of kieselghur, pyrogenic silicas, tricalcium phosphate, calcium
silicates, AI203, MgO, MgC03, ZnO, stearates, fatty amines and the like.
Metal soaps
Metal soaps are the salts of the metals AI, Ba, Ca, Cd, Co, Cr, Cu,
Fe, Li, Mg, Mn, Ni, Pb, Sn, Sr, Zn (not Na or K) with higher fatty, resinic
and
CA 02315137 2000-08-04
49
naphthenic acids (stearates, palmitates, oleates, linoleates, resinates,
laurates, octanoates, ricinoleates, 12-hydroxystearates, naphthenates,
tallates and the like). The metal soaps melt between 15 and 200°C and
generally show colloidal behavior and interfacial activity. Their solubility
in
water is poor. In general, they swell on initial contact with water. In
addition, metal soaps, more particularly Ca, Li, Sr, Ba, Pb, Mn and Mg
soaps, act as lubricants in the production of cleaning tablets.
A particularly preferred metal soap is magnesium stearate.
The cleaning tablets according to the invention contain one or more
metal soaps, more particularly magnesium stearate, in a quantity of
normally 0 to 10% by weight, preferably 0.1 to 5% by weight and more
preferably 1 to 3% by weight.
Powdering materials
Before the particulate premix is compressed to form cleaning tablets,
it may be "powdered" with fine-particle surface treatment materials. This
can be of advantage to the quality and physical properties of both the
premix (storage, tabletting) and the final cleaning tablets. Fine-particle
powdering materials have been known for some time in the art, zeolites,
silicates and other inorganic salts generally being used. However, the
compound is preferably "powdered" with fine-particle zeolite, zeolites of the
faujasite type being preferred. In the context of the present invention, the
expression "zeolite of the faujasite type" encompasses all three zeolites
which form the faujasite subgroup of zeolite structural group 4 (cf. Donald
W. Breck: "Zeolite Molecular Sieves" John Wiley & Sons, New
York/London/Sydney/Toronto, 1974, page 92). Besides zeolite X, there-
fore, zeolite Y and faujasite and mixtures of these compounds may also be
used, pure zeolite X being preferred.
Mixtures or co-crystallizates of faujasite zeolites with other zeolites
- CA 02315137 2000-08-04
which do not have to belong to zeolite structural group 4 may also be used
as powdering materials, in which case at least 50% by weight of the
powdering material consists of a faujasite zeolite.
5 Production
The cleaning tablets according to the invention are produced by first
dry mixing the constituents of the individual phases, which may be
completely or partly pregranulated, and then forming/shaping, more
particularly tabletting, the resulting mixtures using conventional processes.
10 To produce the cleaning tablets according to the invention, the premix is
compacted between two punches in a die to form a solid compactate. This
process, which is referred to in short hereinafter as tabletting, comprises
four phases, namely metering, compacting (elastic deformation), plastic
deformation and ejection.
15 In the most simple case where the cleaning tablets are produced by
the application of pressure to a premix to be tabletted which is
accommodated in the cavity of a press - hereinafter referred to simply as
tabletting - the mixture to be tabletted is compressed directly, i.e. without
preliminary granulation. The advantages of this so-called direct tabletting
20 are its simple and inexpensive application because no other process steps
and hence no other items of equipment are involved. However, these
advantages are offset by disadvantages. Thus, a powder mixture which is
to be directly tabletted must possess adequate plastic deformability and
good flow properties and must not show any tendency to separate during
25 storage, transportation and filling of the die. If a powder mixture
satisfies
these three requirements, the tablets are preferably produced by direct
tabletting. By contrast, if these three requirements are not satisfied by a
particular mixture or are difficult to satisfy, direct tabletting is
preferably not
used for the production of tablets according to the invention, instead
CA 02315137 2000-08-04
51
powder-form components ("primary particles") are agglomerated or
granulated by suitable methods to secondary particles with larger particle
diameters. These granules or mixtures of different granules are then mixed
with individual powder-form additives and the resulting mixtures are
tabletted. In one particular embodiment of the invention, preferred cleaning
tablets are obtained by tabletting a particulate premix of at least one batch
of surfactant-containing granules and at least one subsequently added
powder-form component. The surfactant-containing granules may be
produced by conventional granulation processes, such as mixer and pan
granulation, fluidized bed granulation, extrusion, pelleting or compacting. It
is of advantage so far as the subsequent detergent tablets are concerned if
the premix to be tabletted has a bulk density of at least 500 g/I, preferably
of at least 600 g/I and more preferably above 700 g/I. Another advantage
can arise out of a relatively narrow particle size distribution of the
surfactant
granules used. According to the invention, preferred cleaning tablets are
those in which the granules have particle sizes of 10 to 4,000 pm,
preferably between 100 and 2,000 pm and more preferably between 600
and 1,400 Nm. According to the invention, preferred cleaning tablets
consist of a particulate premix containing granular components and
subsequently incorporated powder-form components, the, or one of the,
fine-particle components subsequently incorporated being a zeolite of the
faujasite type with particle sizes below 100 Nm, preferably below 10 Nm
and more preferably below 5 pm and making up at least 0.2% by weight,
preferably at least 0.5% by weight and more preferably more than 1 % by
weight of the premix to be compressed. The fine-particle aftertreatment
components with the particle sizes mentioned above may be dry-mixed
with the premix to be tabletted. However, it is also possible and preferred
to "stick" them onto the surface of the relatively coarse particles by
addition
of small quantities of liquid components. These powdering techniques are
CA 02315137 2000-08-04
52
widely described in the prior art literature and familiar to the expert.
Liquid
components suitable as adhesion promoters for the powdering materials
are, for example, nonionic surfactants or aqueous solutions of surfactants
or other detergent ingredients. In one preferred embodiment of the
invention, perfume is used as the liquid component for promoting the
adhesion of the powdering materials.
The nongranulated, partly granulated or completely granulated
premix is introduced into the die, the filling level and hence the weight and
shape of the tablet formed being determined by the position of the lower
punch and the shape of the die. Uniform metering, even at high tablet
throughputs, is preferably achieved by volumetric metering of the premix.
As the tabletting process continues, the top punch comes into contact with
the premix and continues descending towards the bottom punch. During
this compaction phase, the particles of the premix are pressed closer
together, the void volume in the filling between the punches continuously
diminishing. The plastic deformation phase in which the particles coalesce
and form the tablet begins from a certain position of the top punch (and
hence from a certain pressure on the premix). Depending on the physical
properties of the premix, its constituent particles are also partly crushed,
the premix sintering at even higher pressures. As the tabletting rate
increases, i.e. at high throughputs, the elastic deformation phase becomes
increasingly shorter so that the tablets formed can have more or less large
voids. In the final step of the tabletting process, the tablet is forced from
the die by the bottom punch and carried away by following conveyors. At
this stage, only the weight of the tablet is definitively established because
the tablets can still change shape and size as a result of physical
processes (re-elongation, crystallographic effects, cooling, etc.).
CA 02315137 2000-08-04
53
Tabletting machines
The tabletting process is carried out in commercially available tablet
presses which, in principle, may be equipped with single or double
punches. In the latter case, not only is the top punch used to build up
pressure, the bottom punch also moves towards the top punch during the
tabletting process while the top punch presses downwards. For small
production volumes, it is preferred to use eccentric tablet presses in which
the punches) is/are fixed to an eccentric disc which, in turn, is mounted on
a shaft rotating at a certain speed. The movement of these punches is
comparable with the operation of a conventional four-stroke engine.
Tabletting can be carried out with a top punch and a bottom punch,
although several punches can also be fixed to a single eccentric disc, in
which case the number of die bores is correspondingly increased. The
throughputs of eccentric presses vary according to type from a few hundred
to at most 3,000 tablets per hour.
For larger throughputs, rotary tablet presses are generally used. In
rotary tablet presses, a relatively large number of dies is arranged in a
circle on a so-called die table. The number of dies varies - according to
model - between 6 and 55, although even larger dies are commercially
available. Top and bottom punches are associated with each die on the
die table, the tabletting pressures again being actively built up not only by
the top punch or bottom punch, but also by both punches. The die table
and the punches move about a common vertical axis, the punches being
brought into the filling, compaction, plastic deformation and ejection
positions by means of curved guide rails. At those places where the
punches have to be raised or lowered to a particularly significant extent
(filling, compaction, ejection), these curved guide rails are supported by
additional push-down members, pull-down rails and ejection paths. The die
is filled from a rigidly arranged feed unit, the so-called filling shoe, which
is
CA 02315137 2000-08-04
54
connected to a storage container for the compound. The pressure applied
to the premix can be individually adjusted through the tools for the top and
bottom punches, pressure being built up by the rolling of the punch shank
heads past adjustable pressure rollers.
To increase throughput, rotary presses can also be equipped with
two filling shoes so that only half a circle has to be negotiated to produce a
tablet. To produce two-layer or multiple-layer tablets, several filling shoes
are arranged one behind the other without the lightly compacted first layer
being ejected before further filling. Given suitable process control, shell
and bull's-eye tablets - which have a structure resembling an onion skin -
can also be produced in this way. In the case of bull's-eye tablets, the
upper surface of the core or rather the core layers is not covered and thus
remains visible. Rotary tablet presses can also be equipped with single or
multiple punches so that, for example, an outer circle with 50 bores and an
inner circle with 35 bores can be simultaneously used for tabletting.
Modern rotary tablet presses have throughputs of more than one million
tablets per hour.
Tabletting machines suitable for step a) of the process according to
the invention can be obtained, for example, from the following companies:
Apparatebau Holzwarth GbR, Asperg, Wilhelm Fette GmbH,
Schwarzenbek, Hofer GmbH, Weil, KILIAN, Cologne, KOMAGE, Kell am
See, KORSCH Pressen GmbH, Berlin, Mapag Maschinenbau AG, Bern
(Switzerland) and Courtoy N.V., Halle (BE/LU). One example of a
particularly suitable tabletting machine is the model HPF 630 hydraulic
double-pressure press manufactured by LAEIS, D.
Three-dimensional form
The cleaning tablets can be made in certain shapes and certain
sizes and may also consist of several phases, i.e. layers, inclusions or
CA 02315137 2000-08-04
cores and rings or shapes with cavities and cavity fillings or inserts.
Suitable shapes are virtually any easy-to-handle shapes, for example
slabs, bars, cubes, squares and corresponding shapes with flat sides and,
in particular, cylindrical forms of circular or oval cross-section. This last
5 embodiment encompasses shapes from tablets to compact cylinders with a
height-to-diameter ratio of more than 1.
At a very early stage, developers of tablet-form products came up
with the idea of releasing certain ingredients into the wash cycle under
defined conditions through differently composed parts or regions of the
10 tablets in order in this way to improve the outcome of the cleaning
process.
Besides the core/jacket tablets and ring/core tablets known for some time
in the pharmaceutical industry, multilayer tablets in particular have been
successfully used and are now available for many aspects of washing and
cleaning or hygiene.
15 In one particular embodiment of the invntion, the cleaning tablet
consists of two or more different phases, preferably two or thre phases,
more preferably two phases, in the form of layers and/or inclusions and/or
cores and rings and/or three-dimensional forms with cavities and cavity
filling or inserts. The difference between the phases may lie in their
20 composition, for example through the separation of incompatible
ingredients, such as bleaching agents and enzymes, and/or different
coloring, and/or in their character, for example compressed and non-
compressed, for example molten/cast, phases. In one preferred
embodiment as a two-phase, more particularly two-layer, cleaning tablet,
25 the two phases are present in a ratio by weight of 10:1 to 1:10, preferably
5:1 to 1:2 and more preferably 3:1 to 1:1.15, for example 2:1 or 1:1.
The portioned pressings may be formed as separate individual
elements which correspond to a predetermined dose of the detergent.
However, it is also possible to form pressings which combine several such
CA 02315137 2000-08-04
56
units in a single pressing, smaller portioned units being easy to break off in
particular through the provision of predetermined weak spots. For the use
of laundry detergents in machines of the standard European type with
horizontally arranged mechanics, it can be of advantage to produce the
portioned pressings as cylindrical or square tablets, preferably with a
diameter-to-height ratio of about 0.5:2 to 2:0.5. Commercially available
hydraulic presses, eccentric presses and rotary presses are particularly
suitable for the production of pressings such as these.
The three-dimensional form of another embodiment of the tablets is
adapted in its dimensions to the dispensing compartment of commercially
available domestic washing machines, so that the tablets can be
introduced directly, i.e. without a dosing aid, into the dispensing
compartment where they dissolve on contact with water. The cleaning
tablets may of course also be used in conjunction with a dosing aid.
Another preferred tablet which can be produced has a plate-like or
slab-like structure with alternately thick long segments and thin short
segments, so that individual segments can be broken off from this "bar" at
the predetermined weak spots, which the short thin segments represent,
and introduced into the machine. This "bar" principle can also be
embodied in other geometric forms, for example vertical triangles which are
only joined to one another at one of their longitudinal sides.
Another preferred multiphase tablet which can be produced has a
plate-like or slab-like structure with alternately thick long segments and
thin
short segments, so that individual segments can be broken off from this
"bar" at the predetermined weak spots, which the short thin segments
represent, and introduced into the machine. This "bar" principle can also
be embodied in other geometric forms, for example vertical triangles which
are only joined to one another at one of their longitudinal sides. In this
case, it is appropriate for optical reasons to make the base of the triangle,
CA 02315137 2000-08-04
57
by which the individual segments are interconnected, as one phase while
the apex forms the second phase. In this embodiment, different coloring of
the two phases is particularly attractive.
In another possible embodiment, however, the various components
are not compressed to form a single tablet, instead the tablets obtained
comprise several layers, i.e. at least two layers. These various layers may
have different dissolving rates. This can provide the tablets with favorable
performance properties. If, for example, the tablets contain components
which adversely affect one another, one component may be integrated in
the more quickly dissolving layer while the other component may be
incorporated in a more slowly dissolving layer so that the first component
can already have reacted off by the time the second component dissolves.
The various layers of the tablets can be arranged in the form of a stack, in
which case the inner layers) dissolve at the edges of the tablet before the
outer layers have completely dissolved. Alternatively, however, the inner
layers) may also be completely surrounded by the layers lying further to
the outside which prevents constituents of the inner layers) from dissolving
prematurely.
In another preferred embodiment of the invention, a tablet consists
of at least three layers, i.e. two outer layers and at least one inner layer,
a
peroxy bleaching agent being present in at least one of the inner layers
whereas, in the case of the stack-like tablet, the two outer layers and, in
the
case of the envelope-like tablet, the outermost layers are free from peroxy
bleaching agent. In another possible embodiment, peroxy bleaching agent
and any bleach activators or bleach catalysts present and/or enzymes may
be spatially separated from one another in one and the same tablet.
Multilayer tablets such as these have the advantage that they can be used
not only via a dispensing compartment or via a dosing unit which is added
to the wash liquor, instead it is also possible in cases such as these to
CA 02315137 2000-08-04
58
introduce the shaped body into the machine in direct contact with the
fabrics without any danger of spotting by bleaching agent or the like.
Coating
Similar effects can also be obtained by coating individual
constituents of the cleaning composition to be compressed or the tablet as
a whole. To this end, the mixtures or tablets to be coated may be sprayed,
for example, with aqueous solutions or emulsions or melts (spraying on of
the coating material) or a coating may be obtained by the process known
as melt coating (dipping of the tablet into the melt or solution). In
preferred
embodiments of the present invention, however, the cleaning tablets are
not provided with a coating which covers the entire tablet.
Fracture resistance
After pressing, the cleaning tablets have high stability. The fracture
resistance of cylindrical tablets can be determined via the diametral fracture
stress. This in turn can be determined in accordance with the following
equation:
0 =
2P
~Dt
where a represents the diametral fracture stress (DFS) in Pa, P is the force
in N which leads to the pressure applied to the tablet that results in
fracture
thereof, D is the diameter of the tablet in meters and t is its height.
Relative eauilibrium moisture
Irrespective of the purpose for which they are to be used, the
cleaning tablets according to the invention preferably have an equilibrium
moisture content of less than 30% at 35°C.
CA 02315137 2000-08-04
59
The relative equilibrium moisture content of the cleaning tablets may
be determined by standard methods. The following procedure was
selected for the present investigations: a water-impermeable 1-liter vessel
with a cover having a closable opening for the insertion of samples was
filled with a total of 300 g of cleaning tablets and kept at a constant
temperature of 23°C for 24 hours in order to guarantee the vessel and
the
substance a uniform temperature. The water vapor pressure in the space
above the tablets can then be determined with a hygrometer (Hygrotest
6100, Testoterm Ltd., England). The water vapor pressure is measured
every 10 minutes until two successive values show no deviation
(equilibrium moisture content). The hygrometer mentioned above enables
the values recorded to be directly displayed in % relative moisture.
Pack
The tablets according to the invention may be combined with a pack
either individually or two or more at a time. The term "pack" in the context
of the present invention always characterizes the primary pack of the
tablets, i.e. the pack which is in direct contact with the surface of the
tablets
on its inside.
The tablet/pack combinations according to the invention may of
course themselves be packed in secondary packs, for example cardboard
boxes or trays, the secondary pack having to meet no other requirements
so that any of the usual materials and systems may be used. Accordingly,
the secondary pack is possible and normal for institutional applications, but
is not necessary.
Wafer vapor transmission rafe
The pack of the tablet(s)/pack combination preferably has a water
vapor transmission rate of 0.1 g/mz/day to less than 20 g/m2/day when the
CA 02315137 2000-08-04
pack is stored at 23°C/85% relative equilibrium humidity. The
temperature
and humidity conditions mentioned are the test conditions specified in DIN
53122, according to which minimal deviations are acceptable (23 ~ 1 °C,
85
~ 2% relative humidity). The water vapor transmission rate of a given pack
5 or material can be determined by other standard methods and is also
described, for example, in ASTM Standard E-96-53T ("Test for Measuring
Water Vapor Transmission of Materials in Sheet Form") and in TAPPI
standard T464 m-45 ("Water Vapor Permeability of Sheet Materials at High
Temperatures and Humidity"). The measurement principle of standard
10 methods is based on the water absorption of anhydrous calcium chloride
which is stored in a container in the corresponding atmosphere, the
container being closed on top by the material to be tested. The water
vapor transmission rate can be calculated from the surface of the container
closed by the material to be tested (permeation surface), the increase in
15 weight of the calcium chloride and the exposure time in accordance with
the following equation:
24 ~ 10000 x
WVTR = ~- [ g / m2 / 24h]
20 A y
where A is the surface area of the material to be tested in cmz, x is the
increase in weight of the calcium chloride in g and y is the exposure time in
h.
25 The relative equilibrium humidity, often referred to as "relative air
humidity", in the measurement of the water vapor transmission rate for the
purposes of the present invention is 85% at 23°C. The absorption
capacity
of air for water vapor increases with temperature to a particular maximum
content, the so-called saturation content, and is expressed in g/m3. For
30 example, 1 m3 of air at 17°C is saturated with 14.4 g of water
vapor, the
- CA 02315137 2000-08-04
61
saturation content at 11 °C being as low as 10 g of water vapor. The
relative air humidity is the ratio expressed in percent between the water
vapor content actually present and the saturation content corresponding to
the prevailing temperature. If, for example, air at 17°C contains 12
g/m3
water vapor, the relative air humidity is (12/14.4)100 = 83%. If this air is
cooled, saturation (100% relative humidity) is reached at the so-called dew
point (in the example 14°C), i.e. a deposit in the form of mist (dew)
is
formed with further cooling. Hygrometers and psychrometers are used for
the quantitative determination of humidity.
The relative equilibrium humidity of 85% at 23°C can be adjusted
to
an accuracy of ~ 2% relative humidity (depending on the instrument used),
for example in humidity-controlled laboratory chambers. Oversaturated
solutions of certain salts also form constant and well-defined relative air
humidities at a given temperature in closed systems, these relative air
humidities being based on the phase equilibrium between the partial
pressure of the water, the saturated solution and the sediment.
Accordingly, the present invention also relates to a combination of
(a) cleaning tablets) containing polyalkylene glycol and a pack containing
the cleaning tablet(s), the pack having a water vapor transmission rate of
0.1 g/m2/day to less than 20 g/m2/day where the pack is stored at
23°C/85% relative equilibrium humidity.
According to the invntion, prefered packs have a water vapor
transmission rate of 0.5 g/m2/day to less than 15 g/m2/day.
Dose
The pack surrounds one or more cleaning tablets, depending on the
embodiment of the invention. In one preferred embodiment of the
invention, a tablet may be made up in such a way that it constitutes a
dosage unit of the cleaner/detergent and may be individually packed or
CA 02315137 2000-08-04
62
tablets may be packed in a pack in numbers which, together, constitute a
dosage unit.
"Individually packed" does not mean that the tablets have to be
accommodated in physically separated packs, instead a tablet can be
removed from the pack without the other individually packed tablets)
present in the pack also having to be taken out. A correpsonding individual
pack is, for example, the blister pack described in the following Examples.
The same applies to the pack unit containing more than one tablet which
may of course be part of a physical combination of several pack units
providing each pack unit can be individually opened while the others
remain closed.
Accordingly, for a prescribed dose of 80 g of detergent/cleaner,
which is typical of laundry detertents, it is possible in accordance with the
invention to produce and individually pack a detergent tablet weighing 80 g.
However, it is also possible in accordance with the invention to pack two
detergent tablets each weighing 40 g as a dosage unit in one pack in order
to obtain a combination according to the invention. This principle may of
course also be extended so that, according to the invention, combinations
of three, four, five or even more cleaning tablets may be accommodated in
one and the same pack.
Two or more tablets in the same pack may of course have different
compositions. In this way, certain components can be spatially separated
from one another in order, for example, to avoid stability problems.
Material and form
The pack may consist of various materials and may assume various
external forms. For economic reasons and in the interests of easier
processability, however, preferred packs are those in which the packaging
material is light in weight, easy to process and inexpensive.
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63
In preferred combinations according to the invention, more
particularly combinations with cleannig tablets, the pack consists of a body
with one or more depressions for accommodating one or more tablets and
a cover closing the depression and holding the tablets) therein. Packs
such as these are known as blister packs. The body is preferably made of
transparent or nontransparent plastic film, more particularly polypropylene
film, with a thickness of preferably 200 to 600 Nm and more particularly 300
to 500 Nm, for example 400 Nm. The cover is normally a preferably
welded-on film of metal, plastic, metal-coated plastic or paper or wax-
coated paper with a thickness of preferably 60 to 200 Nm and more
particularly 100 to 140 pm, for example 120 pm. Suitable cover films are
the commercially available peel, peel-and-push and push-through films
widely used above all in the pharmaceutical industry. A pack of the type in
question is described in the following Examples and in EP 0 903 405 A2
(Unilever) to which reference is made in this regard and of which the
disclosure is hereby incorporated in the present specification.
In other preferred combinations according to the invention, more
particularly combinations with laundry and dishwasher detergent tablets,
the pack consists of a bag of single-layer or laminated paper and/or plastic
film. The cleaning tablets may be introduced without sorting, i.e. loosely,
into a bag of the materials mentioned above. However, for aesthetic
reasons and for sorting the combinations in secondary packs, bags are
filled either with single cleaning tablets or with several cleaning tablets in
sorted form. The term "flow pack" is now commonly used for individual
dosage units of the cleaning tablets accommodated in a bag. Flow packs
may optionally be packed - again preferably sorted - in outer packs which
underscores the compact supply form of detergent tablets. The bags of
single-layer or laminated paper or plastic film preferably used as the pack
may be designed in various ways, for example as inflated bags with no
CA 02315137 2000-08-04
64
center seam or as bags with a center seam which are closed by heat (heat
sealing), adhesives or adhesive tape. Single-layer bag materials are the
known papers, which may optionally be impregnated, and plastic films
which may optionally be co-extruded. Plastic films which may be used as
packs in accordance with the invention are described, for example, in Hans
Domininghaus "Die Kunststoffe and ihre Eigenschaften" 3rd Edition,
VDI Verlag, Diisseldorf, 1988, page 193. Figure 111 of this publication
also provides reference points in respect of the water vapor transmission of
the materials mentioned. Particularly preferred combinations according to
the invention contain a bag of single-layer or laminated plastic film with a
thickness of 10 to 200 Nm, preferably 20 to 100 pm and more preferably 25
to 50 pm as the pack.
Although wax-coated papers in the form of paperboard articles may
also be used in addition to the films or papers mentioned as the pack for
the cleaning, the pack preferably does not comprise any boxes of wax
coated paper.
Examples
Cleaning tablets E1 to E9 according to the invention and comparison
tablets C1 and C2 were produced as described above in the form of
circular disks weighing 25 g with a density of about 1.8 g/cm3 and were
tested for moisture stability. Their compositions are shown in Tables 1 and
2 below along with their dissolving times and lime dissolving power.
In terms of composition and size, the cleaning tablets according to
the invention represent an embodiment suitable for use as lavatory
cleaners. The tablets in Table 1 are lavatory cleaner tablets based on
amidosulfuric acid with and without additions of 1 or 5% by weight of
polyethylene glycol having a molecular weight of 10,000 (PEG 10000),
tablets E1, E2 and C1 being distinguished by high effervescent activity and
CA 02315137 2000-08-04
65
foaming and tablets E3, E4 and C2 by reduced effervescent activity and
foaming.
Table 1
by weight E1 E2 C1 E3 E4 C2
PEG 10000 1 5 - 1 5 -
Amidosulfuric acid 60 60 60 60 60 60
Citric acid 5 5 5 5 5 5
Sodium carbonate 5.48 5.48 5.48 18 12 18
Sodium bicarbonate 24 20 25 - - -
Sodium lauryl sulfate 0.9 0.9 0.9 0.9 0.9 0.9
Sodium perborate~1Hz0 2 2 2 2 2 2
Sodium sulfate - - - 11.48 13.4812.48
Polyvinyl pyrrolidone 0.5 0.5 0.5 0.5 0.5 0.5
Paraffin oil 0.6 0.6 0.6 0.6 0.6 0.6
Silicon dioxide 0.1 0.1 0.1 0.1 0.1 0.1
Perfume 0.4 0.4 0.4 0.4 0.4 0.4
Dye 0.02 0.02 0.02 0.02 0.02 0.02
Lime dissolving power 1337 1366 1357 1309 1271 1320
(mg]
Dissolving time [mins.] 6.5 9.5 6 8 8 7
Tablet E5 is based on citric acid and contains about 2.2% by weight
of PEG 3350. Tablet E6 is based on sodium hydrogen sulfate and
contains 0.5% by weight of PEG 6000 and inter alia sodium percarbonate.
Tablet E7 is based on a 1:1 mixture of amidosulfuric and citric acid and
contains 2% by weight of PEG 10000. Tablet E8 is based on amidosulfuric
acid and contains 5% by weight of PEG 3350 and inter alia sodium
percarbonate and tripolyphosphate, but no polyvinyl pyrrolidone.
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Table 2
by weight E5 E6 E7 E8 E9
Phase Phase
1 2
PEG 10000 - - 2 - 1 1
PEG 6000 - 0.5 - - - -
PEG 3350 2.195 - - 5 - -
Amidosulfuric acid - - 32 60 65 50
Citric acid 65 - 32 5.48 5 5
Sodium hydrogen sulfate- 64 - - - -
Sodium carbonate 30 25 6 21 14 18
Sodium bicarbonate - - 26.5 - - -
Sodium lauryl sulfate0.1 0.9 0.5 0.3 0.9 0.9
Magnesium stearate 2 2.5 - - - -
Sodium percarbonate - 1 - 2 - 4
Sodium tripolyphosphate- - - 6 - -
Sodium sulfate - 4.5 - - 12.48 19.48
Polyvinyl pyrrolidone0.5 0.7 0.5 - 0.5 0.5
Paraffin oil - 0.5 - - 0.6 0.6
Silicon dioxide - - 0.18 - 0.1 0.1
Perfume 0.2 0.4 0.3 0.2 0.4 0.4
Dye 0.005 - 0.02 0.02 0.02 0.02
Lime dissolving power805 886 911 1087 1380
~mg~
Dissolving time (mins.]7 8.5 5 4.5 9
Tablet E9 is a two-phase cleaning tablet which consists of two layers
in the form of circular disks with the same weight and the phase 1 and
phase 2 compositions shown in Table 2, of which only phase 2 contains
bleaching agent. Both phases are based on amidosulfuric acid and contain
1 % by weight of PEG 10000. However, phase 1 has a larger amidosulfuric
acid content while phase 2 has a larger sodium carbonate content and
additionally contains sodium percarbonate.
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Lime dissolving power
The dissolving power for limescale (calcium carbonate) was
determined as follows.
The test was carried out on a plate of white Carrara marble
measuring 75 x 150 x 5 mm. Before the tests, the marble plates were
degreased with ethanol and any residues were brushed off under running
water. The plate was then dried for at least 1 hour at 105°C to
constant
weight and, after cooling, was weighed on an analytical balance (accuracy
~ 1 mg).
Of 8 tablets, 1 liter of a 20% solution was prepared with tap water.
The tablets were dissolved by stirring for 10 minutes at room temperature.
950 ml of the cleaning solution were transferred to a 1 liter glass
beaker (tall form). Before the beginning of the test, the temperature of the
cleaning solution was checked to ensure a value of 20 to 23°C. The
immersion time was 10 minutes. The test plate was then removed,
residues were brushed off under running water and the plate was again
dried at 105°C to constant weight. The quantity of dissolved calcium
carbonate was determined by differential weighing and is shown in the
Tables as the lime dissolving power in mg.
The tablets according to the invention and the comparison tablets
based on amidosulfuric acid showed comparable lime dissolving power. As
expected, the lime dissolving power of tablets E5 to E7 with the alternative
acid base was lower commensurate with to the particular acid component.
Dissolving time
The dissolving time of a tablet is the time which the tablet takes to
visibly dissolve completely in the standing water volume (1 liter) of the U
pipe of a conventional flush toilet on its own, i.e. without any mechanical
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assistance, for example in the form of a stirrer.
The tablets according to the invention and the comparison tablets
showed comparable dissolving times.
Moisture stability
Moisture stability was tested in a commercially available pack. 8
tablets were accommodated in individual cells of a polypropylene blister
pack which, before thermoforming, had a thickness of 400 pm. The blister
pack was closed by a welded-on peel and push film (wall thickness 120
pm) as the cover film.
The packed tablets were stored under different conditions I and II.
Storage I of 80% relafive humidity
The tablets were stored for 4 weeks at a temperature of 30°C/80%
relative air humidity.
Sforage II at more than 80% relafive humidity
The tablets were stored for 2 months at a temperature of 23°C and
in a saturated moisture atmosphere of more than 80% relative humidity. To
this end, the pack was stored in a screw-top 2-liter wide-necked bottle
containing an open 250 ml glass filled with 100 ml of water.
Moisfure stressing of the tablets
To determine the moisture stressing of the packed tablets, the pack
was filled with 6 g of the drying agent silica gel per cell and stored for 21
days at 23 and 30°C in a storage II arrangement.
At 23°C, 224 mg of water were taken up over a period of 21 days;
at
30°C, the figure was 938 mg water. Accordingly, each tablet is exposed
daily in the pack to a quantity of water of up to about 1.3 mg at a storage
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temperature of 23°C and up to about 5.6 mg at a storage temperature of
30°C.
Sforage results
Tablets E1 to E9 according to the invention proved to be moisture-
stable. Neither the tablets nor the blister pack showed any visible signs of
having changed after storage I and storage II under rigorous moisture
conditions. The tablets could be used intact.
By contrast, comparison tablets C1 and C2 were not moisture-
stable. After storage I, tablets C1 had swollen, changed color and partly
reacted with the moisture to form gas, so that the cells of the blister pack
had expanded. After storage II, tablets C1 had again swollen, the cells of
the blister pack had expanded and the tablets could no longer be used.
Tablets C2 had changed color and had swollen slightly with some formation
of gas in the blister pack both after storage I and after storage II.
The various test results show that tablets E1 to E9 according to the
invention were distinguished from comparison tablets C1 and C2 by
superior moisture stability for comparable lime dissolving power and
dissolving time.
The invention may be varied in any number of ways as would be
apparent to a person skilled in the art and all obvious equivalents and the
like are meant to fall within the scope of this description and claims. The
description is meant to serve as a guide to interpret the claims and not to
limit them unnecessarily.
