Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02313587 2000-07-07
CAPSULE FOR CONTROLLED RELEASE OF ACTIVE SUBSTANCES
Field of the Invention
The present invention relates to a capsule for the con
trolled release of active substances and in particular
to the use of this capsule in laundry detergent,
cleaning product, and surfactant compositions and in
pharmaceutical and cosmetic preparations.
Background of the Invention
Capsules for the controlled release of active sub-
stances are known from a multiplicity of applications.
Within the pharmaceutical segment there are systems
featuring what is known as delayed release, i.e., the
active substances are released after a predetermined
space of time following oral intake. In the case of
what is known as controlled release, metering of the
release of the active substances takes place within a
predetermined organ. One generally customary system is
the release of the active substances in the gut, with
the capsules comprising a material which is resistant
to gastric fluid but soluble in the gut. The capsules
dissolve in the gut and the active substance is
released there.
A further field of use of encapsulated active sub-
stances is that of laundry detergents and cleaning
products. Finished compositions frequently include
sensitive substances which may be destroyed by other
components under storage conditions. These substances
may be incorporated in encapsulated form into the
compositions. The encapsulated materials are generally
enveloped by a water-soluble shell which is dissolved
by the washing water, with release ensuing.
In the known capsules, the dissolution process begins
immediately, so that the rate of release of the active
substances is dependent on the dissolution rate of the
capsule material.
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If the components are to be added only in one
particular part of the washing process, i.e., in a
specific wash cycle, then these components are usually
metered by way of corresponding devices arranged in the
washing machines. Domestic washing machines, for
example, include reserve compartments for the prewash,
the main wash, and the rinse cycle. A dishwasher
machine includes reserve compartments for the
detergent, and another for the rinse aid.
The field of laundry detergents and cleaning products
is virtually devoid of capsules which, as in the
pharmaceutical segment, are able to utilize the
different pH environments within the body. Generally,
the pH levels within the individual wash cycles are
very similar. These cycles also show similar
fluctuations in temperature in the heating and cooling
phases. The prior art discloses no system which permits
controlled release of the active substance in a sub-
sequent wash or rinse cycle.
Summary of the Invention
It is an object of the present invention to provide a
capsule having a controlled release system that
releases an active substance at a desired point in
time, i.e., at a predetermined site, following its
supply. A particular object of the invention is to
provide a capsule which may be used in machine washing
and cleaning processes and which releases the active
substance at a predetermined point in time in the
washing process.
The invention accordingly provides a capsule for the
controlled release of active substance, comprising
(A) a substance apt to destroy the capsule wall by
means' of chemical reaction with the capsule
material and/or with a further substance,
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(B) a gas which under storage conditions does not react
with the other components present in the capsule,
and
(C) active substance,
the capsule shell having an aperture for the emergence
of one of the constituents present therein.
The capsule of the invention is suitable for a
multiplicity of applications within the pharmaceutical
and cosmetic segment and also for use in machine
laundry detergents and cleaning products, especially in
compositions for textile laundry and for the machine
cleaning of kitchen- and tableware.
Detailed Description of the Invention
The term "capsule" in the context of the present
invention is not restricted to receptacles having the
form of the capsules known from pharmacy. Rather, in
the context of the present invention, the term
"capsule" denotes receptacles whose walls are
sufficiently stable to withstand the volume expansion
and subsequent contraction to the extent that the
external medium is able to pass into the receptacle's
interior. In addition to the cylindrical capsules with
hemispherical ends that are known from pharmacy, other
geometries are of course also realizable in accordance
with the invention, in particular, for example, tubular
bags made of hard films, spherical, cube-shaped or
tetrahedral packaging forms, etc.
By means of appropriate combination of the materials of
capsule wall and ingredients it is possible to produce
tailored capsules of the invention. The active
substance and the capsule material may also be chosen,
for example, such that the active substance destroys
the material of the capsule. In this specific case,
substance A and substance C would be identical.
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For the release of the active substance from the
capsule it is not necessary for the entire capsule wall
to be destroyed. Rather, for emergence of the contents
from the capsule, it is sufficient for the substance A
to destroy parts of the capsule wall, thereby
permitting the substance C (which may be identical with
A) to emerge from the capsule.
The aperture that is present, in accordance with the
invention, in the capsule shell and which effects the
release mechanism described hereinbelow may initially
be closed. All that is necessary then is for the part
closing the aperture to dissolve under the ambient
conditions of the application, or for the aperture to
open up in another way, so that the activity may begin.
The release mechanism of the capsule of the invention
is essentially temperature-dependent and makes use of
the volume expansion of gases under increasing
temperature. The capsule of the invention is
particularly suitable for use in an aqueous medium
which in the course of the application is heated and
then cooled again. If the capsule of the invention is
added at room temperature to an aqueous environment
which is subsequently heated, the gas volume within the
capsule expands and a small amount of the components A,
B and/or C present therein emerges via the aperture in
the capsule wall. If the system cools back down after
the heating process is at an end, and/or if cold water
is supplied to the external environment of the capsule,
then there is a volume contraction of the gas.
Simultaneously with the volume contraction, substance
from outside, in the aqueous medium water, is taken in
via the aperture in the capsule wall. The incoming
water dissolves the component A, or reacts with it, as
a result of which a medium develops within the capsule
that leads to the destruction or dissolution of the
capsule wall. Simultaneously with, or following, the
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destruction of the capsule wall, the active substance C
is released.
The shape of the capsule is arbitrary; however, it has
proven advantageous if the capsule is of slightly
elongated design. In an elongated shape, the solid
ingredients accumulate in the bottom part and, when the
capsule is used in an aqueous medium, are located below
the water level. In an embodiment of this kind, the
aperture in the capsule wall should also be below the
water level.
The wall of the capsule of the invention should be such
that it is initially inert and insoluble with respect
to the external medium into which the capsule is
introduced at the time of application (for example,
water), and with respect to the components A, B and C
present within the capsule, but at high and/or low pH
values is soluble and may be destroyed, at least
partially, by mechanical forces such as stirring,
pressure, or abrasion. Examples of suitable materials
are polymers which are soluble or dispersible in the
alkaline or acidic range. Examples of suitable polymers
are modified polysaccharides such as carrageenan, guar,
pectin, xanthan, partially hydrolyzed cellulose,
cellulose acetate, hydroxyethyl-, hydroxypropyl- and
hydroxybutylcellulose, methylcellulose, and the like.
Mention may further be made of proteins and modified
proteins, such as gelatin. Further suitable polymers
include acrylates and acrylate polymers. These
materials are described later on below.
In order to meet the abovementioned requirements
imposed on the capsule wall, it may be necessary to use
combinations of different wall materials or else to
employ a multilayer construction of the wall from
different wall materials.
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The capsule wall has an aperture for the emergence of
constituents present in the capsule. This aperture
should be of a size such that, at the time of volume
expansion, at least one of the constituents present in
the capsule is able to emerge, so as to avoid the
capsule bursting as a result of the overpressure which
forms. The size of this aperture is preferably less
than 1 mm, in particular less than 0.5 mm. The
component A is selected such that entry of external
medium into the capsule is followed by dissolution or
destruction of the capsule wall - for example, by the
formation of an aqueous solution which has a pH which
is aggressive for the capsule wall, or by the reaction
of the component A with water to form a gas as a result
of which, within the capsule, an overpressure is
developed which leads ultimately to the destruction of
the capsule and the release of the active substance.
In one preferred embodiment of the present invention,
the component A is a solid acid and one material of the
capsule wall is an acid-soluble polymer. Solid or
crystalline acids used are preferably those which do
not give off any water of crystallization at the
process temperatures, examples being sulfamic acid,
citric acid, and Na,KHS04. As acidifying agents it is
also possible, for example, to use boric acid and also
further alkali metal hydrogen sulfates, alkali metal
dihydrogen phosphates, and other inorganic salts.
Preference, however, is given to the use of organic
acidifying agents, with citric acid being a
particularly preferred acidifying agent. The other
solid mono-, oligo- and polycarboxylic acids, however,
in particular may also be used. Preferred in turn from
this group are tartaric acid, succinic acid, malonic
acid, adipic acid, malefic acid, fumaric acid, oxalic
acid, and polyacrylic acid. Organic sulfonic acids such
as sulfamic acid may likewise be used. A commercially
available acidifying agent which may likewise be used
CA 02313587 2000-07-07
with preference in the context of the present invention
is Sokalan~ DCS (trademark of BASF) , a mixture of
succinic acid (max. 31% by weight), glutaric acid
(max. 50% by weight), and adipic acid (max. 33% by
weight ) .
In another embodiment, the component A is a substance
which gives an alkaline reaction with water, and the
material of the capsule wall is a polymer which is
soluble in the alkaline range. Examples of solid
substances which give alkaline reactions in aqueous
solution are hydroxides, carbonates, hydrogen
carbonates, and/or silicates, preference being given to
alkali metal hydroxides, alkali metal carbonates,
alkali metal hydrogen carbonates, alkali metal
sesquicarbonates, alkali metal silicates, alkali metal
metasilicates, and mixtures of the abovementioned
substances. For the purposes of this invention,
preference is given among the alkali metal salts to the
potassium and in particular the sodium salts,
especially sodium carbonate, sodium hydrogen carbonate,
and sodium sesquicarbonate.
In a further embodiment of the present invention, the
release takes place, as already mentioned above, by the
formation of gas in the interior of the capsule and
subsequent destruction as a result of the overpressure.
In this embodiment, the component A is a substance or a
mixture of substances which reacts with the incoming
water to form gas. Examples of possible substances are
a combination of carbonates, such as alkali metal
carbonates and alkali metal hydrogen carbonates, and a
solid acid, e.g., citric acid, succinic acid, or one or
more of the abovementioned acidifying agents, or cobalt
ammine complexes in combination with resorcinol, an
example which may be mentioned of an appropriate cobalt
ammine complex being [Co (NH3) SCl] C12.
CA 02313587 2000-07-07
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A third possible release mechanism for the active
substance C is the use of swelling agents as
component A. As suitable swelling agents, mention may
be made of cellulose and cellulose derivatives, which
when water penetrates the capsule swell and lead to
destruction and thus to the release of the active
substance. Swelling agents, which because of their
action are also referred to, inter alia, as
disintegrants, increase in volume on ingress of water,
with firstly an increase in their own volume (swelling)
and secondly the possibility, by way of the release of
gases, for the generation of a pressure which bursts
the capsule and causes it to break down into relatively
small particles. Examples of well-known swelling agents
are synthetic polymers such as polyvinylpyrrolidone
(PVP) or natural polymers and/or modified natural
substances such as cellulose and starch and their
derivatives, alginates, or casein derivatives.
Preferred swelling agents used in the context of the
present invention are those based on cellulose. Pure
cellulose has the formal empirical composition (C6HloOs) n
and, considered formally, is a (3-1,4-polyacetal of
cellobiose, which itself is constructed of two
molecules of glucose. Suitable celluloses consist of
from about 500 to 5000 glucose units and, accordingly,
have average molecular masses of from 50,000 to
500,000. Cellulose-based swelling agents which may be
used also include, in the context of the present
invention, cellulose derivatives obtainable by polymer-
analogous reactions from cellulose. Such chemically
modified celluloses include, for example, products of
esterifications and etherifications in which hydroxy
hydrogen atoms have been substituted. However,
celluloses in which the hydroxy groups have been
replaced by functional groups not attached by an oxygen
atom may also be used as cellulose derivatives. The
group of cellulose derivatives embraces, for example,
CA 02313587 2000-07-07
_ g _
alkali metal celluloses, carboxymethylcellulose (CMC),
cellulose esters and cellulose ethers, and amino-
celluloses. Said cellulose derivatives are preferably
not used alone as cellulose-based disintegrants but
instead are used in a mixture with cellulose. The
cellulose derivative content of these mixtures is
preferably less than 50% by weight, with particular
preference less than 20% by weight, based on the
cellulose-based swelling agent. The particularly
preferred cellulose-based swelling agent used is pure
cellulose, free from cellulose derivatives.
The cellulose used as the swelling agent is preferably
not incorporated into the capsule in finely divided
form but instead is converted before its introduction
into a coarser form, by granulation or compaction, for
example. The particle sizes of such disintegrants are
usually above 200 Vim, preferably between 300 and
1600 ~m to the extent of at least 90% by weight, and~in
particular between 400 and 1200 ~m to the extent of at
least 90% by weight.
As a further cellulose-based swelling agent, or as a
constituent of this component, it is possible to use
microcrystalline cellulose. This microcrystalline
cellulose is obtained by partial hydrolysis of
celluloses under conditions which attack only the
amorphous regions (approximately 30% of the total
cellulose mass) of the celluloses and break them up
completely but leave the crystalline regions
(approximately 70%) intact. Subsequent deaggregation of
the microfine celluloses resulting from the hydrolysis
yields the microcrystalline celluloses, which have
primary particle sizes of approximately 5 ~m and may be
compacted, for example, to granules having an average
particle size of 200 Vim.
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One further possible release mechanism for the active
substance C is the use of enzymes as component A. These
enzymes may, for example, be coated in which case the
coating dissolves after slight ingress of water into
the capsule interior, after which the enzymes break
down the capsule material and thus release the active
substance C. Suitable enzymes for use, in dependence on
the capsule material, are all common enzymes such as
proteases, amylases, cellulases, etc., which may
additionally possess a function in the wash or cleaning
cycle. These enzymes are described at length later on
below.
As active substance C it is possible to use any
substances for which controlled release is desired. In
the field of drugs, any desired active substances are
suitable.
In the laundry detergents and cleaning products, the
kind of substances incorporated in capsule form are in
particular those which under normal conditions are not
stable and/or are intended for use in a later stage of
the washing process. Examples of active substances
incorporated in the form of capsules into laundry
detergents and cleaning products are rinse-aid
surfactants, textile treatment compositions (fabric
softeners), enzymes, bleaches, bleaching catalysts,
bleach activators, optical brighteners, dyes,
fragrances, corrosion inhibitors, etc.
The abovementioned rinse-aid surfactants, which are
used in particular in the machine washing of kitchen-
and tableware, and the textile treatment compositions,
such as fabric softener components, which find applica-
tion in the laundering of textiles, are components
which in machine washing and cleaning processes are not
added until a process stage which follows the actual
washing operation. Suitable rinse-aid surfactants are
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all nonionic surfactants, but especially fatty alcohol
polyethylene glycol ethers, fatty alcohol
polyethylene/polypropylene glycol ethers, mixed ethers
and/or hydroxyalkyl polyethylene glycol ethers.
Examples of fatty alcohol polyethylene glycol ethers
are those with the formula (I)
RIO-{CH2CHZO~,,H (I)
to
where Rl is a linear or branched alkyl and/or alkenyl
radical having 6 to 22, preferably 12 to 18, carbon
atoms and nl is numbers from 1 to 5.
Said substances are known commercial products. Typical
examples are adducts of on average 2 or 4 mol of
ethylene oxide onto technical-grade C12~14 coconut fatty
alcohol (Dehydol~ LS-2 and LS-4, respectively, from
Henkel KGaA) or adducts of on average 4 mol of ethylene
oxide onto C14/ls oxo alcohols (Dobanol~ 45-4, from
Shell) . The products may have a conventional or else a
narrowed homolog distribution.
Fatty alcohol polyethylene/polypropylene glycol ethers
are nonionic surfactants of the formula (II)
CH3
R'O-(CH2CH20)~2(CHZCHO)r,,iH (II)
where R4 is a linear or branched alkyl and/or alkenyl
radical having 6 to 22, preferably 12 to 18, carbon
atoms, n2 is numbers from 1 to 5 and m2 is numbers from
1 to 4.
These substances are also known commercial products. A
typical example is an adduct of on average 5 mol of
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ethylene oxide and 4 mol of propylene oxide anto
technical-grade C~z/14 coconut fatty alcohol
(Dehydol~ LS-54, from Henkel KGaA).
Mixed ethers are endgroup-capped fatty alcohol
polyglycol ethers with the formula (III)
CH3
R50-(CHZCH20~,3(CIiZCHO)",3-R6 (III)
where RS is a linear or branched alkyl and/or alkenyl
radical having 6 to 22, preferably 12 to 18 carbon
atoms, n3 is numbers from 1 to 10, m3 is 0 or numbers
from 1 to 4, and R6 is an alkyl radical having 1 to
4 carbon atoms, or a benzyl radical.
Typical examples are mixed ethers of the formula (III)
in which RS is a technical-grade C12/14 cocoalkyl
radical, n3 is 5 or 10, m3 is 0, and R6 is a butyl
group (Dehypon~ LS-54 and LS-104, respectively, from
Henkel KGaA). The use of butyl- and/or benzyl-capped
mixed ethers is particularly preferable on performance
grounds.
Hydroxyalkyl polyethylene glycol ethers are compounds
with the general formula (IV)
OH R3
RS -CH-CH-(OCH2CH20)"4-OR2 (IV)
where RS is hydrogen or a straight-chain alkyl
radical having 1 to 16 carbon atoms,
R3 is a straight-chain or branched alkyl
radical having 4 to 8 carbon atoms,
RZ is hydrogen or an alkyl radical having 1
to 16 carbon atoms, and
n4 is a number from 7 to 30,
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with the proviso that the total number of carbon atoms
in RS and R2 is from 6 to 16.
Examples of textile treatment compositions are, in
particular, cationic surfactants. Suitable cationic
surfactants are all customary surface-active sub-
stances, distinct preference being given to cationic
surfactants having a textile-softening action.
Such cationic active substances with a textile-
softening action are selected with particular
preference from those which may be described by one or
more of the formulae V, VI or VII:
R'
1
R ~ -N~+~-(CH2)n-T-R2 ( V )
(CHz)~ T-Rz
R'
R'-N~+~-(CH2)"-CH-CH2 (VI)
R' T T
R2 R2
R'
R3-N~+'-(CH2)n-T-R' (VU)
R°
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in which each group Rl independently of the others is
selected from C1_6 alkyl, alkenyl or hydroxyalkyl
groups; each group R2 independently of the others is
selected from Ce_28 alkyl or alkenyl groups; R3 - R1 or
(CHz) "-T-R2; R4 - Rl Or Rz Or (CHZ) n-T-R2; T = -CHZ-,
-O-CO- or -CO-O-, and n is an integer from 0 to 5.
Enzymes may be incorporated in the form of liquid or
solid enzyme preparations into the capsules. Suitable
enzymes in this context include in particular those
from the classes of the hydrolases such as the
proteases, esterases, lipases or lipolytic enzymes,
amylases, cellulases, and other glycosyl hydrolases,
and mixtures of said enzymes. All of these hydrolases
contribute in the wash to removing stains such as
proteinaceous, fatty or starchy stains, and instances
of graying. Cellulases and other glycosyl hydrolases
may, furthermore, by removing pilling and microfibrils,
contribute to color retention and to increasing the
softness of the textile. For bleaching, and/or for
inhibiting color transfer, it is also possible to use
oxidoreductases. Especially suitable enzymatic active
substances are those obtained from bacterial strains or
fungi such as Bacillus subtilis, Bacillus licheni-
formis, Streptomyces griseus, Coprinus cinereus, and
Humicola insolens, and also from genetically modified
variants thereof. Preference is given to the use of
proteases of the subtilisin type, and especially to
proteases obtained from Bacillus lentus. Of particular
interest in this context are enzyme mixtures, examples
being those of protease and amylase or protease and
lipase or lipolytic enzymes, or of protease and
cellulase or of cellulase and lipase or lipolytic
enzymes, or of protease, amylase and lipase or
lipolytic enzymes, or of protease, lipase or lipolytic
enzymes and cellulase, but especially protease and/or
lipase-containing mixtures or mixtures with lipolytic
enzymes. Examples of such lipolytic enzymes are the
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known cutinases. Peroxidases or oxidases have also
proven suitable in some cases. The suitable amylases
include, in particular, alpha-amylases, iso-amylases,
pullulanases, and pectinases. Cellulases used are
preferably cellobiohydrolases, endoglucanases and
-glucosidases, which are also called cellobiases, and
mixtures of these. Since different types of cellulase
differ in their CMCase and Avicelase activities, the
desired activities may be established by means of
specific mixtures of the cellulases.
In capsules intended for use in detergents for machine
dishwashing, of course, different enzymes are used in
order to take account of the different substrates
treated and different types of soiling. Suitable
enzymes in this context include in particular those
from the classes of the hydrolases such as the
proteases, esterases, lipases or lipolytic enzymes,
amylases, glycosyl hydrolases, and mixtures of said
enzymes. All of these hydrolases contribute to removing
stains such as proteinaceous, fatty or starchy stains.
For bleaching, it is also possible to use
oxidoreductases. Especially suitable enzymatic active
substances are those obtained from bacterial strains or
fungi such as Bacillus subtilis, Bacillus
licheniformis, Streptomyces griseus, Coprinus cinereus,
and Humicola insolens, and also from genetically
modified variants thereof. Preference is given to the
use of proteases of the subtilisin type, and especially
to proteases obtained from Bacillus lentus. Of
particular interest in this context are enzyme
mixtures, examples being those of protease and amylase
or protease and lipase or lipolytic enzymes, or of
protease, amylase and lipase or lipolytic enzymes, or
of protease, lipase or lipolytic enzymes, but
especially protease and/or lipase-containing mixtures
or mixtures with lipolytic enzymes. Examples of such
lipolytic enzymes are the known cutinases. Peroxidases
CA 02313587 2000-07-07
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or oxidases have also proven suitable in some cases.
The suitable amylases include, in particular, alpha-
amylases, iso-amylases, pullulanases, and pectinases.
The. enzymes may be adsorbed on carrier substances or
embedded in coating substances in order to protect them
against premature decomposition.
The enzymes are usually prepared in a granulated and
encapsulated form and added in that form to the laundry
detergent and cleaning product. In liquid cleaning
products containing water, these granulated and
encapsulated enzymes would dissolve, and so in that
case the use of liquid enzyme concentrates is generally
preferred. Such liquid enzyme concentrates are based
either, homogeneously, on a propylene glycol/water base
or, heterogeneously, as slurry, or are present in a
microencapsulated structure. The use of liquid enzyme
products is likewise possible in the capsules of the
invention.
Preferred liquid proteases are, for example,
Savinase~ L, Durazyrri L, Esperase~ L, and Everlase~ from
Novo Nordisk, Optimase~ L, Purafect~ L, Purafect~ OX L,
Properase~ L from Genencor International, and BLAP~ L
from Biozym Ges.m.b.H.
Preferred amylases are Termamyl~ L, Duramyl~ L, and BAN
from Novo Nordisk, Maxamyl~ WL and Purafect~ HPAm L from
Genencor International.
Preferred lipases are Lipolase~ L, Lipolase~ ultra L and
Lipoprime~ L from Novo Nordisk and Lipomax~ L from
Genencor International.
Slurries or microencapsulated liquid products that may
be used are, for example, products such as those
designated by SL or, respectively, LCC from Novo
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Nordisk. Said commercial liquid enzyme preparations
contain, for example, from 20 to 90% by weight of
propylene glycol or of mixtures of propylene glycol and
water. Capsules preferred in the context of the present
invention are those comprising one or more liquid
amylase preparations and/or one or more liquid protease
preparations.
Substances from the groups of the bleaches and bleach
activators or bleaching catalysts are also suitable as
ingredients for the capsules of the invention. Among
the compounds used as bleaches which yield H202 in
water, particular importance is possessed by sodium
percarbonate. Examples of further bleaches which may be
used are sodium perborate tetrahydrate and sodium
perborate monohydrate, peroxypyrophosphates, citrate
perhydrates, and H202-donating peracidic salts or
peracids, such as perbenzoates, peroxophthalates,
diperazelaic acid, phthaloimino peracid, or diperdo-
decanedioic acid. Capsules of the invention for use in
cleaning products may also comprise bleaches from the
group of the organic bleaches. Typical organic bleaches
are the diacyl peroxides, such as dibenzoyl peroxide
for example. Further typical organic bleaches are the
peroxy acids, particular examples being the alkyl
peroxy acids and the aryl peroxy acids. Preferred
representatives are (a) peroxybenzoic acid and its
ring-substituted derivatives, such as alkylperoxy-
benzoic acids, and also peroxy-a-naphthoic acid and
magnesium monoperphthalate, (b) aliphatic or sub-
stituted aliphatic peroxy acids, such as peroxylauric
acid, peroxystearic acid, s-phthalimidoperoxycaproic
acid [phthaloiminoperoxyhexanoic acid (PAP)], o-carboxy-
benzamidoperoxycaproic acid, N-nonenylamidoperadipic
acid, and N-nonenylamidopersuccinates, and (c) aliphatic
and araliphatic peroxy dicarboxylic acids, such as
1,12-diperoxycarboxylic acid, 1,9-diperoxyazelaic acid,
diperoxysebacic acid, diperoxybrassylic acid, the
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diperoxyphthalic acids, 2-decyldiperoxybutane-1,4-dioic
acid, and N,N-terephthaloyldi(6-aminopercaproic acid)
may be used.
Bleaches in the capsules of the invention used in
detergents for machine dishwashing may also be
substances which release chlorine or bromine. Among the
suitable chlorine- or bromine-releasing materials,
examples include heterocyclic N-bromoamides and
N-chloroamides, examples being 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-dimethylhydantoin, are likewise suitable.
Bleach activators, which boost the action of the
bleaches, may likewise be ingredients in the capsules
of the invention. Known bleach activators are compounds
containing one or more N-acyl and/or O-acyl groups,
such as substances from the class of the anhydrides,
esters, imides and acylated imidazoles or oximes.
Examples are tetraacetylethylenediamine TAED, tetra-
acetylmethylenediamine TAMD, and tetraacetylhexylene-
diamine TAHD, and also pentaacetylglucose PAG,
1,5-diacetyl-2,2-dioxohexahydro-1,3,5-triazine DADHT,
and isatoic anhydride ISA.
Bleach activators which may be used are compounds which
under perhydrolysis conditions give rise to aliphatic
peroxo carboxylic acids having preferably 1 to
10 carbon atoms, in particular 2 to 4 carbon atoms,
and/or substituted or unsubstituted perbenzoic acid.
Suitable substances are those which carry O-acyl and/or
N-acyl groups of the stated number of carbon atoms,
and/or substituted or unsubstituted benzoyl groups.
Preference is given to polyacylated alkylenediamines,
especially tetraacetylethylenediamine (TAED), acylated
CA 02313587 2000-07-07
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triazine derivatives, especially 1,5-diacetyl-
2,4-dioxohexahydro-1,3,5-triazine (DADHT), acylated
glycolurils, especially tetraacetyl glycoluril (TAGU),
N-acylimides, especially N-nonanoylsuccinimide (NOSI),
acylated phenolsulfonates, especially n-nonanoyl- or
isononanoyloxybenzenesulfonate (n- or iso-NOBS),
carboxylic anhydrides, especially phthalic anhydride,
acylated polyhydric alcohols, especially triacetin,
ethylene glycol diacetate, 2,5-diacetoxy-
2,5-dihydrofuran, N-methylmorpholiniumacetonitrile
methyl sulfate (MMA), and the enol esters known from
German Patent Applications DE 196 16 693 and
DE 196 16 767, and also acetylated sorbitol and
mannitol and/or mixtures thereof (SORMAN), acylated
sugar derivatives, especially pentaacetylglucose (PAG),
pentaacetylfructose, tetraacetylxylose and octaacetyl-
lactose, and also acetylated, optionally N-alkylated
glucamine and gluconolactone, and/or N-acylated
lactams, for example, N-benzoylcaprolactam. Hydro-
philically substituted acyl acetals and acyllactams are
likewise used with preference. Combinations of
conventional bleach activators may also be used. In
capsules for machine dishwashing compositions, the
bleach activators are usually used in amounts from 0.1
to 20% by weight, preferably from 0.25 to 15% by
weight, and in particular from 1 to 10% by weight,
based in each case on the total composition.
In addition to the conventional bleach activators, or
instead of them, it is also possible to incorporate
what are known as bleaching catalysts into the
capsules. These substances are bleach-boosting
transition metal salts or transition metal complexes
such as, for example, Mn-, Fe-, Co-, Ru- or Mo-salen
complexes or -carbonyl complexes. Other bleaching
catalysts which may be used include Mn, Fe, Co, Ru, Mo,
Ti, V and Cu complexes with N-containing tripod
CA 02313587 2000-07-07
- 20 -
ligands, and also Co-, Fe-, Cu- and Ru-ammine
complexes.
Preference is given to the use of bleach activators
from the group of the polyacylated alkylenediamines,
especially tetraacetylethylenediamine (TAED), N-acyl
imides, especially N-nonanoylsuccinimide (NOSI),
acylated phenolsulfonates, especially n-nonanoyl- or
isononanoyloxybenzenesulfonate (n- or iso-NOBS),
N-methylmorpholiniumacetonitrile methyl sulfate (MMA),
preferably in amounts of up to 10% by weight, in
particular from 0.1% by weight to 8% by weight,
especially from 2 to 8 % by weight, and with particular
preference from 2 to 6% by weight, based on the total
composition.
Bleach-boosting transition metal complexes, especially
those with 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, with
particular preference cobalt ammine complexes, cobalt
acetato complexes, cobalt carbonyl complexes, the
chlorides of cobalt or of manganese, and manganese
sulfate, are used in customary amounts, preferably in
an amount of un to 5% by weicrht. in particular from
0.0025% by weight to 1% by weight, and with particular
preference from 0.01% by weight to 0.25% by weight,
based in each case on the total composition. In
specific cases, however, it is also possible to use a
greater amount of bleach activator.
When used in laundry detergents and cleaning products,
the capsules of the invention may include corrosion
inhibitors for protecting the ware or the machine, with
special importance in the field of machine dishwashing
being possessed, in particular, by silver protectants.
The known substances of the prior art may be used. In
general it is possible to use, in particular, silver
CA 02313587 2000-07-07
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protectants selected from the group of the triazoles,
benzotriazoles, bisbenzotriazoles, aminotriazoles,
alkylaminotriazoles, and transition metal salts or
transition metal complexes. Particular preference is
given to the use of benzotriazole and/or alkylamino-
triazole. Frequently encountered in cleaner formula-
tions, furthermore, are agents containing active
chlorine, which may significantly reduce corrosion of
the silver surface. In chlorine-free cleaners, use is
made in particular of oxygen-containing and nitrogen-
containing organic redox-active compounds, such as
difunctional and trifunctional phenols, e.g.,
hydroquinone, pyrocatechol, hydroxyhydroquinone, gallic
acid, phloroglucinol, pyrogallol and derivatives of
these classes of compound. Inorganic compounds in the
form of salts and complexes, such as salts of the
metals Mn, Ti, Zr, Hf, V, Co and Ce, also find frequent
application. Preference is given here to the transition
metal salts selected from the group of the manganese
and/or cobalt salts and/or complexes, with particular
preference cobalt ammine complexes, cobalt acetato
complexes, cobalt carbonyl complexes, the chlorides of
cobalt or of manganese, and manganese sulfate.
Similarly, zinc compounds may be used to prevent
corrosion on the ware.
In shaped laundry detergent and cleaning product bodies
which are preferred in the context of the present
invention, the capsule comprises silver protectants
from the group of the triazoles, benzotriazoles,
bisbenzotriazoles, aminotriazoles, alkylaminotriazoles,
and transition metal salts or transition metal
complexes, with particular preference benzotriazole
and/or alkylaminotriazole, in amounts of from 0.01 to
5% by weight, preferably from 0.05 to 4% by weight, and
in particular from 0.5 to 3% by weight, based in each
case on the weight of the total composition that
comprises the capsules.
CA 02313587 2000-07-07
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In order to enhance the esthetic appeal of the capsules
or of the compositions that comprise the capsules, the
capsules may in whole or in part be colored with
appropriate dyes or comprise dyes. Preferred dyes,
whose selection presents no difficulties whatsoever to
the skilled worker, possess a high level of storage
stability and insensitivity to the other ingredients of
the compositions, and to light, and possess no
pronounced affinity for the substrates treated, such as
textile fibers or kitchen- or tableware items, for
example, so as not to stain them.
Preference for use in capsules of the invention for
textile laundering or for incorporation into textile
detergents is given to all colorants which can be
oxidatively destroyed in the washing process, and to
mixes thereof with suitable blue dyes, known as bluing
agents. It has proven advantageous to use colorants
which are soluble in water or at room temperature in
liquid organic substances. Examples of suitable
colorants are anionic colorants, e.g., anionic nitroso
dyes. One possible colorant is, for example, naphthol
green (Colour Index (CI) Part 1: Acid Green 1; Part 2:
10020) which as a commercial product is available, for
example, as Basacid~ Green 970 from BASF, Ludwigshafen,
Germany, and also mixtures thereof with suitable blue
dyes. Further suitable colorants used include Pigmosol~
Blue 6900 (CI 74160), Pigmosol~ Green 8730 (CI 74260),
Basonyl~ Red 545 FL (CI 45170), Sandolan~ Rhodamine
EB400 (CI 45100), Basacid~ Yellow 094 (CI 47005),
Sicovit~ Patent Blue 85 E 131 (CI 42051), Acid Blue 183
(CAS 12217-22-0, CI Acid Blue 183), Pigment Blue 15
(CI 74160), Supranol~ Blue GLW (CAS 12219-32-8, CI Acid
Blue 221), Nylosan~ Yellow N-7GL SGR (CAS 61814-57-1,
CI Acid Yellow 218) and/or Sandolan~ Blue (CI Acid
Blue 182, CAS 12219-26-0).
CA 02313587 2000-07-07
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In the context of the choice of colorant it must be
ensured that the colorants do not have too great an
affinity for the textile surfaces, and especially for
synthetic fibers. At the same time, it should also be
borne in mind when choosing suitable colorants that
colorants possess different stabilities with respect to
oxidation. The general rule is that water-insoluble
colorants are more stable to oxidation than water-
soluble colorants. Depending on the solubility and
hence also on the oxidation sensitivity, the
concentration of the colorant in the laundry detergents
or cleaning products varies. With readily water-soluble
colorants, e.g., the abovementioned Basacid~ Green, or
the likewise abovementioned Sandolan~ Blue, colorant
concentrations chosen are typically in the range from a
few 10-2 to 10-3 o by weight . In the case of the pigment
dyes, which are particularly preferred owing to their
brightness but are less readily soluble in water,
examples being the abovementioned Pigmosol~ dyes, the
appropriate concentration of the colorant in laundry
detergents or cleaning products, in contrast, is
typically from a few 10-3 to 10-4% by weight.
The capsules of the invention may comprise one or more
optical brighteners. These substances, which are also
called whiteners, are used in modern laundry detergents
because even freshly washed and bleached white laundry
has a slight yellow cast. Optical brighteners are
organic dyes which convert a part of the invisible
W radiation of sunlight into longer-wave blue light.
The emission of this blue light closes the "loophole"
in the light reflected by the textile, so that a
textile treated with an optical brightener appears
whiter and lighter to the eye. Since the mechanism of
action of brighteners necessitates that they attach to
the fibers, a distinction is made in accordance with
the fibers to be "dyed" between, for example,
brighteners for cotton, nylon or polyester fibers. The
CA 02313587 2000-07-07
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commercially customary brighteners suitable for
incorporation into laundry detergents belong
essentially to five structural groups: the stilbene
group, the diphenylstilbene group, the coumarin-
quinoline group, the diphenylpyrazoline group, and the
group involving combination of benzoxazole or
benzimidazole with conjugated systems. An overview of
current brighteners may be found, for example, in
G. Jakobi, A. Ldhr "Detergents and Textile Washing",
VCH-Verlag, Weinheim, 1987, pages 94 to 100. Examples
of suitable brighteners are salts of
4,4'-bis[(4-anilino-6-morpholino-s-triazin-
2-yl)amino]stilbene-2,2'-disulfonic acid or compounds
of similar structure which instead of the morpholino
group carry a diethanolamino group, a methylamino
group, an anilino group, or a 2-methoxyethylamino
group. Furthermore, brighteners of the substituted
diphenylstyryl type may be present, examples being the
alkali metal salts of 4,4'-bis(2-sulfostyryl)biphenyl,
4,4'-bis(4-chloro-3-sulfostyryl)biphenyl, or
4-(4-chlorostyryl)-4'-(2-sulfostyryl)biphenyl. Mixtures
of the abovementioned brighteners may also be used.
Fragrances are added to the capsules of the invention
in order to enhance the esthetic appeal of the products
and to provide the consumer with not only the
performance of the product but also a visually and
sensorially "typical and unmistakeable" product. Also
of importance here is the aspect of the long-lasting
fragrancing of textiles or of the delayed release of
fragrance, which masks the unpleasant alkali odor when
dishwashers are opened. As perfume oils and/or
fragrances it is possible to use individual odorant
compounds, examples being the synthetic products of the
ester, ether, aldehyde, ketone, alcohol, and
hydrocarbon types. Odorant compounds of the ester type
are, for example, benzyl acetate, phenoxyethyl
isobutyrate, p-tert-butylcyclohexyl acetate, linalyl
CA 02313587 2000-07-07
- 25 -
acetate, dimethylbenzylcarbinyl acetate, phenylethyl
acetate, linalyl benzoate, benzyl formate, ethyl
methylphenylglycinate, allyl cyclohexylpropionate,
styrallyl propionate, and benzyl salicylate. The ethers
include, for example, benzyl ethyl ether; the aldehydes
include, for example, the linear alkanals having 8-18
carbon atoms, citral, citronellal, citronellyloxy-
acetaldehyde, cyclamen aldehyde, hydroxycitronellal,
lilial and bourgeonal; the ketones include, for
example, the ionones, a-isomethylionone and methyl
cedryl ketone; the alcohols include anethole,
citronellol, eugenol, geraniol, linalool, phenylethyl
alcohol, and terpineol; the hydrocarbons include
primarily the terpenes such as limonene and pinene.
Preference, however, is given to the use of mixtures of
different odorants, which together produce an appealing
fragrance note. Such perfume oils may also contain
natural odorant mixtures, as obtainable from plant
sources, examples being pine oil, citrus oil, jasmine
oil, patchouli oil, rose oil or ylang-ylang oil.
Likewise suitable are clary sage oil, camomile oil,
clove oil, balm oil, mint oil, cinnamon leaf oil, lime
blossom oil, juniperberry oil, vetiver oil, olibanum
oil, galbanum oil and labdanum oil, and also orange
blossom oil, neroliol, orange peel oil, and sandalwood
oil.
The fragrance content of the capsules of the invention
or of the compositions comprising the capsules is
usually up to 2% by weight of the overall formulation.
The fragrances may be incorporated directly into the
capsules or compositions of the invention;
alternatively, it may be advantageous to apply the
fragrances to carriers which intensify the adhesion of
the perfume on the laundry and, by means of slower
fragrance release, ensure long-lasting fragrance of the
textiles. Materials which have become established as
such carriers are, for example, cyclodextrins, it being
CA 02313587 2000-07-07
- 26 -
possible for the cyclodextrin-perfume complexes to be
additionally coated with further auxiliaries.
In addition, the capsules may also comprise components
which have a positive influence on the ease with which
oil and grease are washed off from textiles (these
components being known as soil repellents). This effect
becomes particularly marked when a textile is soiled
that has already been laundered previously a number of
times with a detergent of the invention comprising this
oil- and fat-dissolving component. The preferred oil-
and fat-dissolving components include, for example,
nonionic cellulose ethers such as methylcellulose and
methylhydroxypropylcellulose having a methoxy group
content of from 15 to 30% by weight and a hydroxypropyl
group content of from 1 to 15% by weight, based in each
case on the nonionic cellulose ether, and also the
prior art polymers of phthalic acid and/or terephthalic
acid, and/or derivatives thereof, especially polymers
of ethylene terephthalates and/or polyethylene glycol
terephthalates or anionically and/or nonionically
modified derivatives thereof. Of these, particular
preference is given to the sulfonated derivatives of
phthalic acid polymers and of terephthalic acid
polymers.
Foam inhibitors which may be present in the capsules of
the invention are suitably, for example, soaps,
paraffins or silicone oils, which may if desired have
been applied to carrier materials.
Graying inhibitors have the function of keeping the
dirt detached from the fiber in suspension in the
liquor and so preventing the redeposition of the dirt.
Suitable for this purpose are water-soluble colloids,
usually organic in nature, examples being the water-
soluble salts of polymeric carboxylic acids, glue,
gelatin, salts of ethersulfonic acids of starch or of
CA 02313587 2000-07-07
- 27 -
cellulose, or salts of acidic sulfuric esters of
cellulose or of starch. Water-soluble polyamides
containing acidic groups are also suitable for this
purpose. Furthermore, soluble starch preparations and
starch products other than those mentioned above may be
used, examples being degraded starch, aldehyde
starches, etc. Polyvinylpyrrolidone may also be used.
Preference, however, is given to the use of cellulose
ethers such as carboxymethylcellulose (Na salt),
methylcellulose, hydroxyalkylcellulose, and mixed
ethers such as methylhydroxyethylcellulose, methyl-
hydroxypropylcellulose, methylcarboxymethylcellulose
and mixtures thereof in amounts of from 0.1 to 5% by
weight, based on the compositions.
Since sheetlike textile structures, especially those of
filament rayon, viscose rayon, cotton and blends
thereof, may tend to crease because the individual
fibers are susceptible to bending, buckling,
compressing and pinching transverse to the fiber
direction, the capsules may comprise synthetic crease
control agents. These include, for example, synthetic
products based on fatty acids, fatty acid esters, fatty
acid amides, fatty acid alkylol esters, fatty acid
alkylolamides, or fatty alcohols, which are usually
reacted with ethylene oxide, or else products based on
lecithin or on modified phosphoric esters.
In order to combat microorganisms, the capsules of the
invention may comprise antimicrobial active substances.
In this context a distinction is made, depending on
antimicrobial spectrum and mechanism of action, between
bacteriostats and bactericides, fungiostats and
fungicides, etc. Examples of important substances from
these groups are benzalkonium chlorides, alkylaryl-
sulfonates, halophenols, and phenylmercuric acetate, it
also being possible to do without these compounds
entirely.
CA 02313587 2000-07-07
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In order to prevent unwanted changes to the
compositions and/or the treated textiles or substrates
as a result of oxygen exposure and other oxidative
processes, the capsules may comprise antioxidants. This
class of compound includes, for example, substituted
phenols, hydroquinones, pyrocatechols and aromatic
amines, and also organic sulfides, polysulfides,
dithiocarbamates, phosphates, and phosphonates.
Increased wear comfort may result from the additional
use of antistats which are further added to the
capsules of the invention. Antistats increase the
surface conductivity and thus enable better dissipation
of charges that are formed. External antistats are
generally substances having at least one hydrophilic
molecule ligand, and provide a more or less hygroscopic
film on the surfaces. These antistats, which are
usually surface-active, may be subdivided into
nitrogen-containing (amines, amides, quaternary
ammonium compounds), phosphorus-containing (phosphoric
esters), and sulfur-containing (alkylsulfonates, alkyl
sulfates) antistats. External antistats are described,
for example, in Patent Applications FR 1,156,513, GB
873 214 and GB 839 407. The lauryl- (or
stearyl-)dimethylbenzylammonium chlorides disclosed
here are suitable as antistats for textiles and as
additives to laundry detergents, in which case,
additionally, a hand effect is obtained.
In order to improve the water absorption capacity, the
rewettability of the treated textiles, and to
facilitate ironing of the treated textiles, silicone
derivatives, for example, may be used in the capsules
of the invention used to treat laundry. These
derivatives additionally improve the rinse-out behavior
of the compositions, by virtue of their foam-inhibiting
properties. Examples of preferred silicone derivatives
CA 02313587 2000-07-07
- 29 -
are polydialkylsiloxanes or alkylarylsiloxanes where
the alkyl groups have one to five carbon atoms and are
totally or partially fluorinated. Preferred silicones
are polydimethylsiloxanes, which may if desired have
been derivatized and in that case are amino-functional
or quaternized, or have Si-OH, Si-H and/or Si-C1 bonds.
The viscosities of the preferred silicones at 25°C are
in the range between 100 and 100,000 centistokes, it
being possible to use the silicones in amounts of
between 0.2 and 5% by weight, based on the overall
composition.
Finally, the capsules of the invention for textile
detergents may also comprise UV absorbers, which attach
to the treated textiles and improve the light stability
of the fibers. Compounds which have these desired
properties are, for example, the compounds which are
active via radiationless deactivation, and derivatives
of benzophenone having substituents in positions) 2
and/or 4. Also suitable are substituted benzotriazoles,
acrylates which are phenyl-substituted in position 3
(cinnamic acid derivatives), with or without cyano
groups in position 2, salicylates, organic Ni com-
plexes, and also natural substances such as
umbelliferone and the endogenous urocanic acid.
It is of course also possible to incorporate further
ingredients of laundry detergents and cleaning
products, examples being builders, cobuilders, further
surfactants, especially anionic surfactants, etc., into
the capsules of the invention. The incorporation of any
pharmaceutical or cosmetic active substance is also
possible without problems, so that the advantages of
the controlled release may be utilized in a very wide
variety of fields of use with the aid of the capsules
of the invention.
CA 02313587 2000-07-07
- 30 -
As component B it is possible to use any desired gas
compatible with the other components in the capsule.
Examples are air, NZ, O2, noble gases and noble gas
mixtures, and C02.
The capsules of the invention may be produced in
various ways. One possibility is to fill prefabricated
capsule parts comprising the abovementioned materials
with components A and C and then to fit the capsule
parts together. Prefabricated capsule parts are
available commercially in the form of so-called hard
capsules. The amount of the gas component B is
determined by the amount of components A and C
introduced. If the capsule parts are filled in air,
then the gas component is air. Where a gas other than
air is to be used as the gas component, filling
generally takes place under the corresponding gas
atmosphere.
After the capsule has been sealed, it is provided with
the aperture, usually by means of a pointed article
with the appropriate diameter. Alternatively, use may
also be made of capsule shells which have already been
perforated beforehand.
A further mode of production consists in the
preparation of soft capsules. This takes place
industrially by the so-called Scherer process. In this
process, two strips of the capsule wall materials
(e. g., gelatin strips) are combined in counter-rotating
shaping rolls, with capsule shaping and capsule filling
taking place simultaneously. The capsule aperture may
in this case be made during the capsule shaping/filling
process, or else in a downstream process step.
As already mentioned, in order to obtain the stated
properties of the capsule wall it may be sensible or
necessary to apply one or more layers of further wall
CA 02313587 2000-07-07
- 31 -
materials to the capsules. This can be done, for
example, by means of immersion processes, film coating,
or in the fluidized bed process.
It is also possible to produce microcapsules of the
invention which allow the release mechanism. In this
case it is possible to have recourse to the common
production processes, followed by the making of one or
more microholes.
Appropriate capsule materials are, as already
mentioned, polymers in particular. The materials
mentioned earlier on above, such as carrageenan, guar,
pectin, xanthan, cellulose and its derivatives, and
gelatin, are described below.
Carrageenan is a formed extract, with a composition
similar to that of agar, of North Atlantic red algae
which belong to the Florideae, and is named for the
Irish coastal town of Carragheen. The carrageenan,
precipitated from the hot-water extract of the algae,
is a colorless to sandy-colored powder having molecular
masses of 100,000-800,000 and a sulfate content of
approximately 25%, which is very readily soluble in
warm water. In carrageenan, three principal con-
stituents are distinguished: the gel-forming K fraction
consists of D-galactose 4-sulfate and 3,6-anhydro-a-D-
galactose, having alternate glycoside linkages in the
1,3 and 1,4 positions (agar, in contrast, contains
3,6-anhydro-a-L-galactose). The non-gelling ~, fraction
is composed of D-galactose 2-sulfate with 1,3-glycoside
linkages and of D-galactose 2,6-Bisulfate residues with
1,4 linkages, and is readily soluble in cold water.
1-Carrageenan, composed of D-galactose 4-sulfate in
1,3 linkage and 3,6-anhydro-a-D-galactose 2-sulfate in
1,4 linkage, is both water-soluble and gel-forming.
Further types of carrageenan are likewise labeled with
Greek letters: a, Vii, y, ~, v, ~, ~, cu, x. The nature of
CA 02313587 2000-07-07
- 32 -
cations present (K, NH4, Na, Mg, Ca) also influences
the solubility of the carrageenans. Semisynthetic
products which contain only one ionic type and are
likewise possible for use in capsule materials in the
context of the present invention are also called
carrag(h)eenates.
The guar which may be used as a capsule material in the
context of the present invention, also called guar gum,
is a grayish white powder obtained by milling the
endosperm of the guar bean (Cyamopsis tetragonobolus),
which belongs to the family of the Leguminosae and was
originally endemic in the Indian and Pakistani region
but has since been cultivated in other countries as
well, for example, in the southern USA. The principal
constituent of guar, with up to about 85% by weight of
the dry matter, is guaran (guar gum, Cyamopsis gum);
secondary constituents are proteins, lipids, and
cellulose. Guaran itself is a polygalactomannan, i.e.,
a polysaccharide whose linear chain is composed of
unsubstituted mannose units (see formula VIII) and
mannose units substituted in the C6 position by a
galactose residue (see formula IX) in (3-D-(1~4)
linkage.
OH CHZOH
Galactose > O
HO
HO
CH20H O gCH2 OH
OH
SOHO ~~ .~- Mannose --~. ~ HO
g 2 1
VIII IX
The ratio of VIII:IX is approximately 2:1; the IX
units, in contrast to what was originally assumed, are
not strictly alternating but are instead arranged in
CA 02313587 2000-07-07
- 33 -
pairs or triplets in the polygalactomannan molecule.
Data on the molecular mass of guaran vary with values
of approximately 2.2105-2.2106 g/mol, depending on the
degree of purity of the polysaccharide - the high value
was determined on a highly purified product -
significantly and correspond to approximately 1350-
13,500 sugar units/macromolecule. Guaran is insoluble
in the majority of organic solvents.
The pectins, which are likewise suitable for use as
capsule material, are high molecular mass glycosidic
plant substances which are very widespread in fruits,
roots, and leaves. Pectins consist essentially of
chains of 1,4-a-glycosidically linked galacturonic acid
units with 20-80% of their acid groups esterified with
methanol, a distinction being made between high-
esterification (>50%) and low-esterification (<50%)
pectins. The pectins have a folded leaf structure which
positions them in the center between starch and
cellulose molecules. Their macromolecules also contain
some glucose, galactose, xylose and arabinose, and have
weakly acidic properties.
COOCH3 OH COOCH3 OH
_O~O O O.
OH OH r OH OH
.O ~0 ~O
OH COOCH3 OH ~COOGH3
Fruit pectin contains 95%, beet pectin up to 85%
galacturonic acid. The molecular masses of the various
pectins vary between 10,000 and 500,000. The structural
properties as well are highly dependent on the degree
of polymerization; for example, the fruit pectins in
the dried state form asbestoslike fibers while the flax
pectins form fine, granular powders.
CA 02313587 2000-07-07
- 34 -
The pectins are prepared by extraction with dilute
acids predominantly from the inner portions of citrus
fruit peels, fruit residues, or sugar beet chips.
Xanthan may also be used as a capsule material in
accordance with the invention. Xanthan is a microbial
anionic heteropolysaccharide produced by Xanthomonas
campestris and certain other species under aerobic
conditions, having a molecular mass of from 2 to
15 million daltons. Xanthan is formed of a chain
comprising (3-1,4-linked glucose (cellulose) with side
chains. The structure of the subgroups comprises
glucose, mannose, glucuronic acid, acetate, and
pyruvate, the viscosity of the xanthan being determined
by the number of pyruvate units. Xanthan may be
described by the following formula:
CHZOH CH20H
O O' n
OH O v -O
~ n
H3C-C-O-CHZ O
O
OH
HO
M'~ COO-
O O
O OH
M'' - OOC O O
OH HO OH M+ = Na,K,ll2 Ca
HsC O
Basic unit of xanthan
The celluloses and their derivatives have already been
described above as capsule ingredients. The capsules
may of course also be produced from such materials. In
addition to cellulose and cellulose derivatives, it is
CA 02313587 2000-07-07
- 35 -
also possible to use (modified) dextrins, starch, and
starch derivatives as capsule materials.
Suitable nonionic organic capsule materials are
dextrins, examples being oligomers and polymers of
carbohydrates obtainable by partial hydrolysis from
starches. The hydrolysis may be conducted in accordance
with customary processes - for example, acid- or
enzyme-catalyzed processes. The products in question
are preferably hydrolysis products having average
molecular masses in the range from 400 to
500,000 g/mol. Preference is given to a polysaccharide
having a dextrose equivalent (DE) in the range from 0.5
to 40, in particular from from 2 to 30, DE being a
customary measure of the reducing action of a
polysaccharide in comparison with dextrose, which
possesses a DE of 100. Dextrins suitable for use
include not only maltodextrins having a DE of between 3
and 20 and dry glucose syrups having a DE of between 20
and 37 but also what are known as yellow dextrins and
white dextrins having higher molecular masses in the
range from 2000 to 30,000 g/mol.
The oxidized derivatives of such dextrins comprise the
reaction products with oxidizing agents capable of
oxidizing at least one alcohol function of the
saccharide ring to the carboxylic acid function.
Oxidized dextrins of this kind and processes for
preparing them are known, for example, from European
Patent Applications EP-A-0 232 202, EP-A-0 427 349,
EP-A-0 472 042 and EP-A-0 542 496 and International
Patent Applications WO 92/18542, WO 93/08251,
WO 93/16110, WO 94/28030, WO 95/07303, WO 95/12619 and
WO 95/20608. Likewise suitable is an oxidized
oligosaccharide in accordance with German Patent
Application DE-A-196 00 018. A product oxidized at C6
of the saccharide ring may be particularly
advantageous.
CA 02313587 2000-07-07
- 36 -
Starch as well may be used as capsule material for the
capsules of the invention. Starch is a homoglycan in
which the glucose units are linked a-glycosidically.
Starch is composed of two components of different
molecular weight: approximately 20-30% straight-chain
amylose (MW approx. 50,000-150,000) and 70-80%
branched-chain amylopectin (MW approx. 300,000-
2,000,000), with small amounts of lipids, phosphoric
acids, and cations being present as well. Whereas
amylose forms long, helical, interlooped chains
comprising approximately 300-1200 glucose molecules,
owing to the 1,4 linkage, in the case of amylopectin
the chain branches by 1,6 linkage, after on average
25 glucose units, to form a treelike structure
comprising approximately 1500-12,000 molecules of
glucose. In addition to straight starch, starch
derivatives obtainable by polymer-analogous reactions
from starch are also suitable for preparing capsules in
the context of present invention. Examples of such
chemically modified starches include products of
esterifications and etherifications in which hydroxy
hydrogen atoms have been substituted. Alternatively,
starches in which the hydroxy groups have been replaced
by functional groups not attached via an oxygen atom
may be used as starch derivatives. The group of the
starch derivatives includes, for example, alkali metal
starches, carboxymethylstarch (CMS), starch esters and
ethers, and amino starches.
Among the proteins and modified proteins, gelatin is of
outstanding significance as capsule material. Gelatin
is a polypeptide (molecular mass: approx. 15,000-
>250,000 g/mol) obtained principally by hydrolysis
under acidic or alkaline conditions of the collagen
present in the skin and bones of animals. The amino
acid composition of gelatin corresponds largely to that
of the collagen from which it was obtained, and varies
CA 02313587 2000-07-07
- 37 -
as a function of its provenance. The use of gelatin as
a water-soluble envelope material is extremely wide-
spread, especially in pharmacy, in the form of hard or
soft gelatin capsules.
Further polymers suitable for use as capsule materials
are synthetic polymers, which are preferably water-
swellable and/or water-soluble. These polymers hail in
particular from the following groups:
a) water-soluble nonionic polymers from the group of
al) polyvinylpyrrolidones
a2) vinylpyrrolidone-vinyl ester copolymers
a3) cellulose ethers
a4) (modified) polyvinyl alcohols
b) water-soluble amphoteric polymers from the group
of
bl) alkylacrylamide-acrylic acid copolymers
b2) alkylacrylamide-methacrylic acid copolymers
b3) alkylacrylamide-methylmethacrylic acid
copolymers
b4) alkylacrylamide-acrylic acid-alkylaminoalkyl-
(meth)acrylic acid copolymers
b5) alkylacrylamide-methacrylic acid-alkylamino-
alkyl(meth)acrylic acid copolymers
b6) alkylacrylamide-methylmethacrylic acid-alkyl-
aminoalkyl(meth)acrylic acid copolymers
b7) alkylacrylamide-alkyl methacrylate-alkylamino-
ethyl methacrylate-alkyl methacrylate
copolymers
b8) copolymers of
b8i) unsaturated carboxylic acid
CA 02313587 2000-07-07
- 38 -
b8ii) cationically derivatized unsaturated
carboxylic acids
b8iii) if desired, further ionic or nonionic
monomers
c) water-soluble zwitterionic polymers from the
group of
cl) acrylamidoalkyltrialkylammonium chloride-
acrylic acid copolymers and their alkali metal
and ammonium salts
c2) acrylamidoalkyltrialkylammonium chloride-
methacrylic acid copolymers and their alkali
metal and ammonium salts
c3) methacroylethyl betaine-methacrylate
copolymers
d) water-soluble anionic polymers from the group of
dl) vinyl acetate-crotonic acid copolymers
d2) vinylpyrrolidone-vinyl acrylate copolymers
d3) acrylic acid-ethyl acrylate-N-tert-butylacryl-
amide terpolymers
d4) graft polymers of vinyl esters, esters of
acrylic acid or methacrylic acid alone or in a
mixture, copolymerized with crotonic acid,
acrylic acid or methacrylic acid with poly-
alkylene oxides and/or polyalkylene glycols
d5) grafted and crosslinked copolymers from the
copolymerization of
d5i) at least one monomer of the nonionic
tYPe,
d5ii) at least one monomer of the ionic
type,
d5iii) polyethylene glycol, and
CA 02313587 2000-07-07
- 39 -
d5iv) a crosslinker
d6) copolymers obtained by copolymerizing at least
one monomer from each of the three following
groups:
d6i) esters of unsaturated alcohols and
short-chain saturated carboxylic acids
and/or esters of short-chain saturated
alcohols and unsaturated carboxylic
acids,
d6ii) unsaturated carboxylic acids,
d6iii) esters of long-chain carboxylic acids
and unsaturated alcohols and/or esters
of the carboxylic acids of group d6ii)
with saturated or unsaturated,
straight-chain or branched C$_la alcohol
d7) terpolymers of crotonic acid, vinyl acetate
and an allyl or methallyl ester
d8) tetra- and pentapolymers of
d8i) crotonic acid or allyloxyacetic acid
d8ii) vinyl acetate or vinyl propionate
d8iii) branched allyl or methallyl esters
d8iv) vinyl ethers, vinyl esters or
straight-chain allyl or methallyl
esters
d9) crotonic acid copolymers with one or more
monomers from the group consisting of
ethylene, vinylbenzene, vinyl methyl ether,
acrylamide and water-soluble salts thereof
d10) terpolymers of vinyl acetate, crotonic acid
and vinyl esters of a saturated aliphatic
a-branched monocarboxylic acid
e) water-soluble cationic polymers from the group of
CA 02313587 2000-07-07
- 40 -
el) quaternized cellulose derivatives
e2) polysiloxanes with quaternary groups
e3) cationic guar derivatives
e4) polymeric dimethyldiallylammonium salts and
their copolymers with esters and amides of
acrylic acid and methacrylic acid
e5) copolymers of vinylpyrrolidone with quater-
nized derivatives of dialkylaminoacrylate and
-methacrylate
e6) vinylpyrrolidone-methoimidazolinium chloride
copolymers
e7) quaternized polyvinyl alcohol
e8) polymers indicated under the INCI designations
Polyquaternium 2, Polyquaternium 17, Poly-
quaternium 18, and Polyquaternium 27.
Water-soluble polymers in the sense of the invention
are those polymers which are soluble to the extent of
more than 2.5% by weight at room temperature in water.
The capsules of the invention may be prepared from
individual polymers of those mentioned above;
alternatively, mixtures or multi-layer laminar
constructions of the polymers may be used. The polymers
are described in more detail below.
Water-soluble polymers which are preferred in
accordance of the invention are nonionic. Examples of
suitable nonionic polymers are the following:
polyvinylpyrrolidones, as marketed, for example,
under the designation Luviskol~ (BASF). Polyvinyl-
pyrrolidones are preferred nonionic polymers in the
context of the invention.
CA 02313587 2000-07-07
- 41 -
Polyvinylpyrrolidones [poly(1-vinyl-2-pyrrolidin-
ones)], abbreviated PVP, are polymers of the
general formula (X)
CH ~ CH2
N
~O
prepared by free-radical addition polymerization of
1-vinylpyrrolidone by processes of solution or
suspension polymerization using free-radical initiators
(peroxides, azo compounds). The ionic polymerization of
the monomer yields only products having low molecular
masses. Commercially customary polyvinylpyrrolidones
have molecular masses in the range from approx. 2500-
750,000 g/mol, which are characterized by stating the
K values and - depending on the K value - have glass
transition temperatures of 130-175°. They are supplied
as white, hygroscopic powders or as aqueous solutions.
Polyvinylpyrrolidones are readily soluble in water and
a large number of organic solvents (alcholos, ketones,
glacial acetic acid, chlorinated hydrocarbons, phenols,
etc) .
- Vinylpyrrolidone-vinyl ester copolymers, as
marketed for example under the trademark Luviskol~
(BASF). Luviskol~ VA 64 and Luviskol~ VA 73, each
vinylpyrrolidone-vinyl acetate copolymers, are
particularly preferred nonionic polymers.
The vinyl ester polymers are polymers obtainable from
vinyl esters and featuring the grouping of the
formula (XI)
CA 02313587 2000-07-07
- 42 -
-CH2-CH-
O' R
(XI)
as the characteristic basic structural unit of the
macromolecules. Of these, the vinyl acetate polymers
(R = CH3) with polyvinyl acetates, as by far the most
important representatives, have the greatest industrial
significance .
The vinyl esters are polymerized free-radically by
various processes (solution polymerization, suspension
polymerization, emulsion polymerization, and bulk
polymerization). Copolymers of vinyl acetate with
vinylpyrrolidone comprise monomer units of the
formulae (I) and (II)
- Cellulose ethers, such as hydroxypropylcellulose,
hydroxyethylcellulose and methylhydroxypropyl-
cellulose, as marketed for example under the
trademarks Culminal~ and Benecel~ (AQUALON).
Cellulose ethers may be described by the general
formula (XII)
RocH2 oR
_o o Ro o_
Ro o d
R RO H2
(XII),
where R is H or an alkyl, alkenyl, alkynyl, aryl,
or alkylaryl radical. In preferred products, at
least one R in formula (XII) is -CHZCH2CH2-OH or
-CH2CH2-OH. Cellulose ethers are prepared
industrially by etherifying alkali metal cellulose
(e.g., with ethylene oxide). Cellulose ethers are
CA 02313587 2000-07-07
- 43 -
characterized by way of the average degree of
substitution, DS, and/or by the molar degree of
substitution, MS, which indicate how many hydroxyl
groups of an anhydroglucose unit of cellulose have
reacted with the etherifying reagent or how many
moles of the etherifying reagent have been added
on, on average, to one anhydroglucose unit.
Hydroxyethylcelluloses are water-soluble above a DS
of approximately 0.6 and, respectively, an MS of
approximately 1. Commercially customary
hydroxyethyl- and hydroxypropylcelluloses have
degrees of substitution in the range of 0.85-1.35
(DS) and 1.5-3 (MS), respectively. Hydroxyethyl-
and -propylcelluloses are marketed as yellowish
white, odorless and tasteless powders in greatly
varying degrees of polymerization. Hydroxyethyl-
and -propylcelluloses are soluble in cold and hot
water and in some (water-containing) organic
solvents, but insoluble in the majority of
(anhydrous) organic solvents; their aqueous
solutions are relatively insensitive to changes in
pH or addition of electrolyte.
Polyvinyl alcohols, denoted PVAL for short, are
polymers of the general structure
(-CHZ-CH(OH)-J"
including small fractions of structural units of the
[-CH2-CH(OH)-CH(OH}-CH2]
type. Since the corresponding monomer, the vinyl
alcohol, is unstable in free form, polyvinyl alcohols
are prepared by way of polymer-analogous reactions by
hydrolysis, but industrially in particular by alkali-
catalyzed transesterification of polyvinyl acetates
CA 02313587 2000-07-07
- 44 -
with alcohols (preferably methanol) in solution. These
industrial processes also make it possible to obtain
PVALs having a predeterminable residual fraction of
acetate groups.
Commercially customary PVAL (e. g., Mowiol~ grades from
Hoechst) are commercialized as yellowish white powders
or granules having degrees of polymerization in the
range of approx. 500-2500 (corresponding to molecular
masses of approximately 20,000-100,000 g/mol) and have
different degrees of hydrolysis of 98-99 or 87-89 mol%.
They are, therefore, partially hydrolyzed polyvinyl
acetates having a residual acetyl group content of
approximately 1-2 or 11-13 mol%.
The water-solubility of PVAL may be reduced by after-
treatment with aldehydes (acetalization), by complexing
with Ni salts or Cu salts, or by treatment with
dichromates, boric acid and/or borax, and so adjusted
to desired levels.
Further polymers suitable in accordance with the
invention are water-soluble amphopolymers. The generic
term amphopolymers embraces amphoteric polymers, i.e.,
polymers whose molecule includes both free amino groups
and free -COOH or S03H groups and are capable of
forming inner salts; zwitterionic polymers whose
molecule contains quaternary ammonium groups and -COO-
OR -S03- groups, and polymers containing -COOH or S03H
groups and quaternary ammonium groups. An example of an
amphopolymer which may be used in accordance with the
invention is the acrylic resin obtainable under the
designation Amphomer~, which constitutes a copolymer of
tert-butylaminoethyl methacrylate, N-(1,1,3,3-tetra-
methylbutyl)acrylamide, and two or more monomers from
the group consisting of acrylic acid, methacrylic acid
and their simple esters. Likewise preferred
amphopolymers are composed of unsaturated carboxylic
CA 02313587 2000-07-07
- 45 -
acids (e. g., acrylic and methacrylic acid),
cationically derivatized unsaturated carboxylic acids,
(e. g., acrylamidopropyltrimethylammonium chloride),
and, if desired, further ionic or nonionic monomers, as
evident, for example, from German Laid-Open
Specification 39 29 973 and the prior art cited
therein. Terpolymers of acrylic acid, methyl acrylate
and methacrylamidopropyltrimonium chloride, as avail-
able commercially under the designation
Merquat~ 2001 N, are particularly preferred ampho-
polymers in accordance with the invention. Further
suitable amphoteric polymers are, for example, the
octylacrylamide-methyl methacrylate-tert-butylamino-
ethyl methacrylate-2-hydroxypropyl methacrylate
copolymers available under the designations Amphomer~
and Amphomer~ LV-71 (DELFT NATIONAL).
Examples of suitable zwitterionic polymers are the
addition polymers disclosed in German Patent
Applications DE 39 29 973, DE 21 50 557, DE 28 17 369
and DE 37 08 451. Acrylamidopropyltrimethylammonium
chloride-acrylic acid or -methacrylic acid copolymers
and their alkali metal salts and ammonium salts are
preferred zwitterionic polymers. Further suitable
zwitterionic polymers are methacryloylethyl betaine-
methacrylate copolymers, which are obtainable com-
mercially under the designation Amersette~ (AMERCHOL).
Anionic polymers that are suitable in accordance with
the invention include:
- vinyl acetate-crotonic acid copolymers, as in
commercialized, for example, under the designation
Resyn~ (NATIONAL STARCH), Luviset~ (BASF) and
Gafset~ (GAF) .
' CA 02313587 2000-07-07
- 46 -
In addition to monomer units of the above formula (II),
these polymers also have monomer units of the general
formula (IV)
[-CH(CH3)-CH(COOH)-]" (IV)
- Vinylpyrrolidone-vinyl acrylate copolymers, obtain-
able for example under the trademark Luviflex~
(BASF). A preferred polymer is the vinyl-
pyrrolidone-acrylate terpolymer obtainable under
the designation LuvifleX VBM-35 (BASF).
- Acrylic acid-ethyl acrylate-N-tert-butylacrylamide
terpolymers, which are marketed for example under
the designation Ultrahold~ strong (BASF).
- Graft polymers of vinyl esters, esters of acrylic
acid or methacrylic acid alone or in a mixture,
copolymerized with crotonic acid, acrylic acid or
methacrylic acid with polyalkylene oxides and/or
polyalkylene glycols
Such grafted polymers of vinyl esters, esters of
acrylic acid or methacrylic acid alone or in a mixture
with other copolymerizable compounds onto polyalkylene
glycols are obtained by polymerization under hot
conditions in homogeneous phase, by stirring the
polyalkylene glycols into the monomers of the vinyl
esters, esters of acrylic acid or methacrylic acid, in
the presence of free-radical initiators.
Vinyl esters which have been found suitable are, for
example, vinyl acetate, vinyl propionate, vinyl
butyrate, vinyl benzoate, and esters of acrylic acid or
methacrylic acid which have been found suitable are
those obtainable with low molecular weight aliphatic
alcohols, i.e., in particular, ethanol, propanol,
CA 02313587 2000-07-07
- 47 -
isopropanol, 1-butanol, 2-butanol, 2-methyl-1-propanol,
2-methyl-2-propanol, 1-pentanol, 2-pentanol,
3-pentanol, 2,2-dimethyl-1-propanol, 3-methyl-
1-butanol; 3-methyl-2-butanol, 2-methyl-2-butanol,
2-methyl-1-butanol, and 1-hexanol.
Suitable polyalkylene glycols include in particular
polyethylene glycols and polypropylene glycols.
Polyethylene glycols are polymers of ethylene glycol
which satisfy the general formula XIII
H-(O-CHZ-CH2)~-OH (XIII)
in which n may adopt values between 1 (ethylene glycol)
and several thousand. For polyethylene glycols there
exist various nomenclatures, which may lead to
confusion. It is common in the art to state the average
relative molecular weight after the letters "PEG", so
that "PEG 200" characterizes a polyethylene glycol
having a relative molecular mass of from about 190 to
about 210. For cosmetic ingredients, a different
nomenclature is used, in which the abbreviation PEG is
provided with a hyphen and the hyphen is followed
directly by a number which corresponds to the number n
in the abovementioned formula XIII. According to this
nomenclature (known as the INCI nomenclature, CTFA
International Cosmetic Ingredient Dictionary and
Handbook, 5th Edition, The Cosmetic, Toiletry and
Fragrance Association, Washington, 1997), for example,
3 0 PEG- 4 , PEG- 6 , PEG- 8 , PEG- 9 , PEG-10 , PEG-12 , PEG-14 , and
PEG-16 may be used. Polyethylene glycols are available
commercially, for example, under the trade names
Carbowax~ PEG 200 (Union Carbide), Emkapol~ 200 (ICI
Americas), Lipoxol~ 200 MED (HtJLS America), Polyglycol~
E-200 (Dow Chemical), Alkapol~ PEG 300 (Rhone-Poulenc),
Lutrol~ E300 (BASF), and the corresponding trade names
with higher numbers.
' CA 02313587 2000-07-07
- 48 -
Polypropylene glycols (abbreviation PPGs) are polymers
of propylene glycol which satisfy the general
formula XIV
H-(O-CH-CH2)"OH (XIV)
CH3
in which n may adopt values between 1 (propylene
glycol) and several thousand. Industrially significant
in this case are, in particular, di-, tri- and
tetrapropylene glycol, i.e., the representatives where
n = 2, 3 and 4 in formula VI.
In particular, it is possible to use the vinyl acetate
copolymers grafted onto polyethylene glycols and the
polymers of vinyl acetate and crotonic acid grafted
onto polyethylene glycols.
- Grafted and crosslinked copolymers from the
copolymerization of
i) at least one monomer of the nonionic type,
ii) at least one monomer of the ionic type,
iii) polyethylene glycol, and
iv) a crosslinker
The polyethylene glycol used has a molecular weight of
between 200 and several million, preferably between 300
and 30,000.
The nonionic monomers may be of very different types
and include the following preferred monomers: vinyl
acetate, vinyl stearate, vinyl laurate, vinyl
propionate, allyl stearate, allyl laurate, diethyl
maleate, allyl acetate, methyl methacrylate, cetyl
vinyl ether, stearyl vinyl ether, and 1-hexene.
CA 02313587 2000-07-07
- 49 -
The nonionic monomers may equally be of very different
types, among which particular preference is given to
the presence in the graft polymers of crotonic acid,
allyloxyacetic acid, vinylacetic acid, malefic acid,
acrylic acid, and methacrylic acid.
Preferred crosslinkers are ethylene glycol dimeth-
acrylate, diallyl phthalate, ortho-, meta- and para-
divinylbenzene, tetraallyloxyethane, and polyallyl-
saccharoses containing 2 to 5 allyl groups per molecule
of saccharin.
The above-described grafted and crosslinked copolymers
are formed preferably of:
i) from 5 to 85% by weight of at least one monomer
of the nonionic type,
ii) from 3 to 80% by weight of at least one monomer
of the ionic type,
iii) from 2 to 50% by weight, preferably from 5 to 30%
by weight, of polyethylene glycol, and
iv) from 0.1 to 8% by weight of a crosslinker, the
percentage of the crosslinker being shaped by the
ratio of the overall weights of i), ii) and iii).
- Copolymers obtained by copolymerizing at least one
monomer from each of the three following groups:
i) esters of unsaturated alcohols and short-
chain saturated carboxylic acids and/or
esters of short-chain saturated alcohols and
unsaturated carboxylic acids,
ii) unsaturated carboxylic acids,
iii) esters of long-chain carboxylic acids and
unsaturated alcohols and/or esters of the
carboxylic acids of group ii) with saturated
' CA 02313587 2000-07-07
- 50 -
or unsaturated, straight-chain or branched
C$_18 alcohols
Short-chain carboxylic acids and alcohols here are
those having 1 to 8 carbon atoms, it being possible for
the carbon chains of these compounds to be interrupted,
if desired, by divalent hetero-groups such as -O-,
-NH-, and -S-.
- Terpolymers of crotonic acid, vinyl acetate, and an
allyl or methallyl ester
These terpolymers contain monomer units of the general
formulae (II) to (IV) (see above) and also monomer
units of one or more allyl or methallyl esters of the
formula XV:
R' R3
RZ-C-C(O)-O-CHz-C=CHZ (XV)
CH3
in which R3 is -H or -CH3, R2 is -CH3 or -CH (CH3) 2 and Rl
is -CH3 or a saturated straight-chain or branched Cl_s
alkyl radical and the sum of the carbon atoms in the
radicals R1 and R2 is preferably 7, 6, 5, 4, 3 or 2.
The abovementioned terpolymers result preferably from
the copolymerization of from 7 to 12% by weight of
crotonic acid, from 65 to 86% by weight, preferably
from 71 to 83 % by weight, of vinyl acetate and from 8
to 20% by weight, preferably from 10 to 17% by weight,
of allyl or methallyl esters of the formula XV.
- Tetra- and pentapolymers of
i) crotonic acid or allyloxyacetic acid
ii) vinyl acetate or vinyl propionate
CA 02313587 2000-07-07
- 51 -
iii) branched allyl or methallyl esters
iv) vinyl ethers, vinyl esters or straight-chain
allyl or methallyl esters
- Crotonic acid copolymers with one or more monomers
from the group consisting of ethylene,
vinylbenzene, vinyl methyl ether, acrylamide and
the water-soluble salts thereof
- Terpolymers of vinyl acetate, crotonic acid and
vinyl esters of a saturated aliphatic a-branched
monocarboxylic acid.
Particularly appropriate capsule materials among the
anionic polymers are polycarboxylates/polycarboxylic
acids, polymeric polycarboxylates, polyaspartic acid,
polyacetals, and dextrins, which are described below.
Examples of organic capsule materials which may be used
are the polycarboxylic acids which may be used in the
form of their sodium salts but also in free form.
Polymeric polycarboxylates are, for example, the alkali
metal salts of polyacrylic acid or of polymethacrylic
acid, examples being those having a relative molecular
mass of from 500 to 70,000 g/mol.
The molecular masses reported for polymeric poly-
carboxylates, for the purposes of this document, are
weight-average molecular masses, MW, of the respective
acid form, determined fundamentally by means of gel
permeation chromatography (GPC) using a W detector.
Measurement was made against an external polyacrylic
acid standard, which owing to its structural similarity
to the polymers under investigation provides realistic
molecular weight values. These figures differ markedly
from the molecular weight values obtained using
polystyrenesulfonic acids as the standard. The
CA 02313587 2000-07-07
- 52 -
molecular masses measured against polystyrenesulfonic
acids are generally much higher than the molecular
masses reported in this document.
Suitable polymers are, in particular, polyacrylates,
which preferably have a molecular mass of from 2000 to
20,000 g/mol. Owing to their superior solubility,
preference in this group may be given in turn to the
short-chain polyacrylates, which have molecular masses
of from 2000 to 10,000 g/mol, and with particular
preference from 3000 to 5000 g/mol.
Also suitable are copolymeric polycarboxylates,
especially those of acrylic acid with methacrylic acid
and of acrylic or methacrylic acid with malefic acid.
Copolymers which have been found particularly suitable
are those of acrylic acid with malefic acid, containing
from 50 to 90% by weight acrylic acid and from 50 to
10% by weight malefic acid. Their relative molecular
mass, based on free acids, is generally from 2000 to
70,000 g/mol, preferably from 20,000 to 50,000 g/mol,
and in particular from 30,000 to 40,000 g/mol.
In order to improve the solubility in water, the
polymers may also contain allylsulfonic acids, such as
allyloxybenzenesulfonic acid and methallylsulfonic
acid, for example, as monomers.
Particular preference as capsule materials is also
given to biodegradable polymers comprising more than
two different monomer units, examples being those
comprising, as monomers, salts of acrylic acid and of
malefic acid, and also vinyl alcohol or vinyl alcohol
derivatives, or those comprising, as monomers, salts of
acrylic acid and of 2-alkylallylsulfonic acid, and also
sugar derivatives.
CA 02313587 2000-07-07
- 53 -
Further preferred copolymeric capsule materials are
those described in German Patent Applications
DE-A-43 03 320 and DE-A-44 17 734, whose monomers are
preferably acrolein and acrylic acid/acrylic salts,
and, respectively, acrolein and vinyl acetate.
Similarly, further preferred capsule materials that may
be mentioned include polymeric amino dicarboxylic
acids, their salts or their precursor substances.
Particular preference is given to polyaspartic acids
and their salts and derivatives.
Further suitable capsule materials are polyacetals,
which may be obtained by reacting dialdehydes with
polyol carboxylic acids having 5 to 7 carbon atoms and
at least 3 hydroxyl groups. Preferred polyacetals are
obtained from dialdehydes such as glyoxal, glutar
aldehyde, terephthalaldehyde and mixtures thereof and
from polyol carboxylic acids such as gluconic acid
and/or glucoheptonic acid.
Further polymers which may be used with preference as
capsule materials are cationic polymers. Among the
cationic polymers, the permanently cationic polymers
are preferred. "Permanently cationic" refers according
to the invention to those polymers which independently
of the pH of the composition (i.e., both of the capsule
and of the remaining composition that may be present)
have a cationic group. These are generally polymers
which include a quaternary nitrogen atom, in the form
of an ammonium group, for example.
Examples of preferred cationic polymers are the
following:
Quaternized cellulose derivatives, as available
commercially under the designations Celquat~ and
Polymer JR~. The compounds Celquat~ H 100, Celquat~
' CA 02313587 2000-07-07
- 54 -
L 200 and Polymer JR 400 are preferred quaternized
cellulose derivatives.
- Polysiloxanes with quaternary groups, such as, for
example, the commercially available products
Q2-7224 (manufacturer: Dow Corning; a stabilized
trimethylsilylamodimethicone), Dow Corning~ 929
emulsion (comprising a hydroxyl-amino-modified
silicone, also referred to as amodimethicone),
SM-2059 (manufacturer: General Electric), SLM-55067
(manufacturer: blacker), and Abil~-Quat 3270 and
3272 (manufacturer: Th. Goldschmidt; diquaternary
polydimethylsiloxanes, Quaternium-80),
- Cationic guar derivatives, such as in particular
the products marketed under the trade names
Cosmedia~ Guar and Jaguar~,
- Polymeric dimethyldiallylammonium salts and their
copolymers with esters and amides of acrylic acid
and methacrylic acid. The products available
commercially under the designations Merquat~ 100
(poly(dimethyldiallylammonium chloride)) and
Merquat~ 550 (dimethyldiallylammonium chloride-
acrylamide copolymer) are examples of such cationic
polymers.
- Copolymers of vinylpyrrolidone with quaternized
derivatives of dialkylamino acrylate and
methacrylate, such as, for example, with diethyl
sulfate-quaternized vinylpyrrolidone-dimethylamino
methacrylate copolymers. Such compounds are
available commercially under the designations
Gafquat~ 734 and Gafquat~ 755.
- Vinylpyrrolidone-methoimidazolinium chloride
copolymers, as offered under the designation
Luviquat~ .
- Quaternized polyvinyl alcohol
and also polymers known under the designations
- Polyquaternium 2
- Polyquaternium 17,
- Polyquaternium 18, and
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- Polyquaternium 27,
having quaternary nitrogen atoms in the polymer main
chain. These polymers are designated in accordance with
the INCI nomenclature; detailed information can be
found in the CTFA International Cosmetic Ingredient
Dictionary and Handbook, 5th Edition, The Cosmetic,
Toiletry and Fragrance Association, Washington, 1997,
which is expressly incorporated herein by reference.
Cationic polymers which are preferred in accordance
with the invention are quaternized cellulose
derivatives and also polymeric dimethyldiallylammonium
salts and copolymers thereof. Cationic cellulose
derivatives, especially the commercial product Polymer~
JR 400, are especially preferred cationic polymers.
The capsules of the invention may be used, for example,
in pharmaceutical and cosmetic preparations, and in
surfactant, laundry detergent, rinse, laundering aid,
cleaning product, and textile aftertreatment
compositions. It is possible, for example, to provide a
laundry detergent and cleaning composition comprising
only the capsules of the invention, which are dosed by
the user into the washing machine or dishwasher. Of
course, it is also possible to add the capsules to an
otherwise completely formulated cosmetic composition or
to a laundry detergent and cleaning composition in
order to give said composition additional utility
through the controlled release of certain active
substances.
The compositions to which the capsules of the invention
are added may be liquid, gellike, pasty, pulverulent or
granular, or in the form of compact tablets, with
hardly any limits imposed on formulation freedom.
By virtue of the temperature-controlled release
mechanism from the capsules of the invention it is
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possible to attain controlled release of the capsule
ingredients, which opens up new performance dimensions
to the products.
For example, it is possible to add the capsules of the
invention to a particulate detergent for machine
dishwashing. In this case the capsules of the invention
are designed so that the release of the ingredients is
initiated only after cooling of the medium surrounding
them (the detergent liquor). On cooling, the medium
surrounding the capsule enters the capsule, where it
triggers a reaction which at least partially destroys
the capsule wall. The duration of this procedure, and
thus the time between the cooling of the external
medium and the release of the active substances from
the capsule, may be varied by way of the thickness of
the capsule wall, the physical and/or chemical
stability of the capsule wall, the nature of the
reaction destroying the capsule wall, and/or the
aggressiveness of the ingredients toward the capsule
wall following entry of the external medium. For
instance, capsules of the invention may be produced
which do not release their ingredients in the main wash
cycle (and also in optional prewash cycles) in a
domestic dishwasher. The main wash cycle is followed by
intermediate wash cycles with cold water, so that the
external medium enters into the capsule. Appropriate
formulation of the capsule ensures that the active
substances are not released until the rinse cycle,
where they develop their action. Thus, for example,
rinse surfactants, acidifying agents or scale
inhibitors may be ingredients of the capsules, thereby
bringing about a rinse-clean effect. In addition to
this chemical formulation, a physical formulation may
be necessary depending on the type of dishwasher, so
that the capsules of the invention are not pumped off
in the machine when the water is changed and hence are
no longer available for the rinse cycle. Standard
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domestic dishwashers, upstream of the detergent-liquor
pump, which pumps the water or cleaning solution from
the machine after the individual cleaning cycles,
comprise a sieve insert, intended to prevent clogging
of the pump by food residues. If the user cleans
heavily soiled kitchen- and tableware, then this sieve
insert requires regular cleaning, which is a simple
option owing to the ease of access and removeability.
The capsules of the invention, then, are preferably so
designed in terms of their size and shape that they do
no pass through the sieve insert of the dishwasher even
after the cleaning cycle, i.e., after exposure to
agitation in the machine and to the detergent solution.
This ensures that capsules of the invention are present
in the dishwasher in the rinse cycle, these capsules
releasing the active substances) under the action of
the colder water after the main wash cycle, by at least
partial destruction of the capsule wall, and so
bringing the desired clean-rinse effect. Particulate
machine dishwashing compositions that are preferred in
the context of the present invention are those wherein
the capsules of the invention they comprise have
particle sizes of between 1 and 20 mm, preferably
between 1.5 and 15 mm, and in particular between 2 and
12 mm.
In particulate dishwashing compositions of this kind,
the capsules of the invention, having the sizes stated
above, may project from the matrix of the other
particulate ingredients; alternatively, the other
particles may likewise have sizes within the stated
range, so that, overall, a detergent composition is
formulated that comprises large detergent particles and
capsules. Especially if the capsules of the invention
are colored, i.e., have a red, blue, green, or yellow
color, for example, it is advantageous for the
appearance of the product, i.e. of the overall
detergent composition, if the capsules are visibly
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larger than the matrix comprising the particles of the
other ingredients of the detergent composition. Here,
preference is given to particulate machine dishwashing
compositions which (not taking into account the
capsules) have particle sizes between 200 and 3000 ~,m,
preferably between 300 and 2500 ~.m, and in particular
between 400 and 2000 ~,m.
If detergent compositions of this kind are formulated
as a powder mixture, then - especially if there are
large differences between the sizes of capsules and
detergent matrix - on the one hand partial separation
may occur when the pack is shaken, and on the other
hand dosing may be different in two successive washing
operations, since the user does not always
automatically dose equal quantities of detergent and
capsules. If it is desired technically to use an
identical amount for each washing operation, this can
be realized by the packaging - familiar to the skilled
worker, of the compositions of the invention in water-
soluble film bags. The present invention also provides
particulate machine dishwashing compositions wherein
one dose unit is welded in a water-soluble film bag. Of
course, other cosmetic or pharmaceutical preparations
or laundry detergent and cleaning compositions, such as
textile detergents, for example, may also be provided
in an entirely analogous manner.
By this means, the user need only insert a bag,
containing for example a detergent powder and a
plurality of visually distinctive capsules, into the
dosing drawer of his or her dishwasher. This embodiment
of the present invention is therefore a visually
attractive alternative to conventional detergent
tablets.
The detergent compositions of the invention may be
prepared in conventional manner. A process for
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preparing pulverulent machine dishwashing compositions
with a rinse-clean effect, in which a conventional
pulverulent machine dishwashing composition is mixed
with capsules of the invention comprising surfactants
and/or acidifying agents and/or scale inhibitors, is
therefore also provided with the present invention.
The above-described desired retention of the capsules
in the machine, even when the water is changed, may be
realized not only by the abovementioned enlargement of
the capsules but also by a reduction in the size of the
holes in the sieve insert . In this way, it is possible
for formulate machine dishwashing compositions having a
uniform average particle size of less than, for
example, from 4 to 12 mm. For this purpose, the product
of the invention, in which the capsules as well have
relatively low particle sizes, is provided with a sieve
insert which replaces or covers the insert present in
the machine. The present invention additionally
provides a kit of parts comprising a pulverulent
machine dishwashing composition of the invention and a
sieve insert for domestic dishwashers.
As already mentioned, the novel combination of
composition and sieve insert permits the formulation of
compositions in which the capsules as well have
relatively low particle sizes. Kits of parts of the
invention wherein the particle sizes of the machine
dishwashing composition (taking into account the
capsules) are in the range from 400 to 2500 Vim,
preferably from 500 to 1600 ~,m, and in particular from
600 to 1200 ~.m, are preferred.
In order to prevent blockages of the added sieve insert
by food residues, the mesh size or hole size chosen
should not be too small. Here, preference is given to
kits of parts of the invention wherein the mesh size or
hole size of the sieve insert is from 1 to 4 mm and the
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rinse aid particles are larger than this mesh size or
hole size of the sieve insert.
The kit of parts of the invention is not restricted to
the particular form of the sieve insert in which said
insert replaces or covers the insert present in the
machine. In accordance with the invention it is also
possible and preferred to provide the kit of parts with
a sieve insert having the form of a basket which may be
hung in a known manner in the dishwasher - on the
cutlery basket, for example. In this way, a sieve
insert of such design replaces the dispensing cup,
i.e., the user doses the machine dishwashing
composition of the invention directly into this sieve
insert, which acts in the manner described above in the
wash and rinse cycles.
The above example was based closely on conditions in
standard domestic dishwashers. It is readily evident
that, in an entirely analogous manner, pulverulent
laundry detergents may be formulated which release, for
example, fabric softener active substances only after
the main wash cycle, from capsules of the invention
comprising such active substances. In the fields of
pharmacy, cosmetics, rinsing, and cleaning products in
general, as well, in an entirely analogous manner, it
is possible to formulate compositions which release the
desired active substance from the capsules of the
invention.
It is of course also possible to add the capsules of
the invention to compact compositions or to incorporate
them into them. For example, laundry detergent and
cleaning product tablets may be produced which comprise
one or more of the capsules of the invention. In this
case, the capsules) may be attached either on or in
the tablet. The first-mentioned embodiment may be
realized, for example, by adhesively bonding one or
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more capsules onto a conventionally produced tablet.
The last-mentioned embodiment comprises, for example,
the insertion of one or more capsules of the invention
into the cavities of pre-produced tablets which have
depressions or holes passing through them. Particularly
attractive from a visual standpoint is the insertion of
a capsule of the invention into a ring-shaped tablet.
Examples
Production of capsules for use in machine dishwashing
compositions
Example 1
The bottom parts of hard gelatin capsules of size 000
(volume 1.37 ml) and those of size 0 (volume 0.68 ml)
from the company WEPA were filled with the substances
shown in Table 1. Subsequently, the capsules were put
together and the top and bottom parts were firmly
bonded. The capsules were coated with a basic
polyacrylate (Eudragit° E from Rohm), giving a polymer
coat with a thickness of between 0.2 and 0.3 mm. The
aperture, with a diameter of 0.5 mm, was made in the
bottom part of the capsule with the aid of a needle.
Subsequently, the capsule prepared in this way was
placed in a glass beaker containing warm water at 20°C.
The water was heated to 65 ° C ( stage I ) ; of ter reaching
this temperature, the capsule remained at this
temperature for 10 minutes. The capsule was then placed
for 5 minutes into water at 35°C (stage II) , which was
subsequently heated again to 65°C (stage III). This
experimental procedure simulates the temperature/time
regime of a universal program at 65°C in a dishwasher.
The ingredients of the individual capsules, and the
capsule weight during the procedure and at the end of
the experiment, are shown in Table 1 below.
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Table 1
Capsule contents AmountCapsule
weight
fgl
InitialStage Stage Stage
I II III
Polytergent~1 1.4 1.72 1.65 1.10 -
Polytergent~1 (70%);0.7 0.90 ? 0.55 -
Citric anhydride/
soda (30%)
Polytergent~1 (70%)0.7 0.95 0.80 0.4 -
PEG 15502 (15%)
citric
anhydride/soda (15%)
Citric anhydride and soda were used in a weight ratio
of 1:1
5 1 Polytergent° SLF-18 B 45: ethylene oxide-propylene
oxide block copolymer (alcohol alkoxylate from
Olin Chemicals, softening point 25-45°C)
Polyethylene glycol with a molecular weight of
1550
Example 2
In this example, hard gelatin capsules of size 000
(volume 1.37 ml) from 4AEPA were treated further as
follows: the bottom part of the capsules was initially
prepared with 80-100 mg of polyethylene glycol
(PEG 3000), an inner coating being applied in the
region of the capsule end. Subsequently, the bottom
part of the capsule was filled with the following
composition:
Ingredient Amount [% by weight]
Polytergent~ SLF18B45 74.8
Sulfamic acid 14.0
Cetylstearyl alcohol 11.2
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The amount of contents in the capsules was 1.3 g.
Following the assembly of the capsule, the residual
volume of air enclosed in the capsule was 10% of the
total volume.
Various coatings were subsequently applied to the
capsules, the composition of said coatings being
indicated, in % by weight, in the table below.
Ingredient Formulation Formulation Formulation
1 2 3
Eudragit~ E 100.0 73.0 -
Vitacel~ P 290 - 27.0 53.0
Eudragit~ S 12.5 - - 47.0
P
The following capsules were produced:
Type l: 0.25 mm coat of formulation 2
Type 2: 0.04 mm coat of formulation 1, then 0.15 mm
coat of formulation 3
The capsules were subsequently provided with a hole
(diameter 0.5 mm) at the capsule end.
The capsules produced in this way were each used
together with a tablet-form detergent in a 55°C and a
65°C program in standard commercial dishwashers (Bosch
S 712, Miele G 590). The rinse aid tank of the machines
was emptied prior to the tests, so that any rinse-clean
effects arising are brought about by the capsules of
the invention.
Observation over the running time of the different
programs revealed no visual changes in the capsules of
type 1 and of type 2 during the wash cycle and the
intermittent rinsing. During the final rinse cycle, the
capsules broke down and the contents were released.
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In all of the tests, the rinse-clean effects on
glasses, plates and pans were at least equivalent to
those found in comparative tests with conventional
rinse-aid dosing via the automatic mechanism of the
machine.
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.
