Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
1
PROCESS FOR MANUFACTURING BLEACHING COMPOSITIONS
COMPRISING CHLORINE AND BROMINE SOURCES
AND PRODUCT THEREOF
FIELD OF THE INVENTION
The present invention relates to a process for the manufacture of alkaline
bleaching compositions useful to the consumer, especially as products for hard
surface cleaning, bleaching or disinfectancy. The products comprise both
chlorine and bromine bleach sources. The process has mixing sequences and
starting ingredient selections which provide unexpectedly improved product.
BACKGROUND OF THE INVENTION
Hard surface cleaners, bleaches and disinfectants are well-known formulated
consumer products. They are useful for treating all manner of soiled kitchen,
bathroom, sink, tub, shower, toilet bowl and counter top surfaces.
Such consumer products are known to include hypochlorite bleach.
Hypochlorite is desirable for its high effectiveness as a bleach and
disinfectant.
However, it has several disadvantages, including that it can sometimes be too
aggressive, tends to leave an unpleasant odor on the hands, and is not always
stable on storage in a consumer product formulation.
Bromine containing compounds have been used in specialized circumstances
for bleaching or disinfectancy. However they tend to be expensive and are
often even more demanding in terms of storage stability than the chlorine
analogs.
CA 02254799 1998-11-13
WO 97/43392 PCT/LTS96/07089
2
Sulfamic acid has been used as a cleaner, especially in acidic cleaners
delivering high concentrations of the acid.
The chemistry of sulfamate-containing systems with halogens is extraordinarily
complex and research in this area continues to this day.
Despite the partly known features of the art, there is an ongoing need for
hard
surface cleaners, bleaches and disinfectants suitable for consumer use which
are improved in one or more of their characteristics including having superior
effectiveness as a bleach and disinfectant, being less aggressive, tending to
leave very low odor or even pleasant odor on the hands, and being highly
stable on storage.
Accordingly, an improved process for making such compositions is provided
herein, and the alkaline bleaching compositions secured thereby.
The process herein has several advantages, including that it is easy to
operate
and is safe and effective for its intended purpose. Surprisingly, it delivers
a
product which is actually superior to the product which is achieved when
numerous other mixing sequences are employed.
BACKGROUND ART
Commonly assigned U.S. 3,583,922, Mc Clain and Meyer, June 8, 1971 and
Canadian Patent Publ. CA 860279 A, published January 5, 1971 describe a
solid composition for rapid removal of tannic acid stains having pH not less
than 10.5 consisting of 0-95°~ abrasive, up to 10% surfactant, 0-60%
alkaline
builder, a stable compound, preferably chlorinated trisodium orthophosphate,
to
provide 0.5°r6-5°~ available chlorine, sulfamic acid to produce
preferably a ratio
of CI to sulphamic acid of 500 to 1:1, preferably 3:1 to 6:1, optionally with
additives. Such additives can include bromides, perfumes or borax. The
compositions can be adjusted for sink cleaning or mechanical dishwashing.
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
3
JP 63108099 A, Lion Corp., published May 12, 1988 describes a bleaching
agent for controlling chlorine odor containing a specific ratio of
hypochlorite
and sulfamic acid and/or sulfamate and pH adjusting agents. The ratio is 2-8
wt% hypochlorite based on "the amount of the effective chlorine" (sic) and
there
is a 0.25 to 1.5 mol ratio of sulfamic acid, and/or a sulfamate, to
hypochlorite.
JP 63161088 A, Lion Corp., published July 4, 1988 describes bleaching
compositions for cloth comprising mainly hydrogen peroxide and sulfamic acid
andlor water-soluble sulfamate and hypohalous acid and/or a water-soluble
hypohalite salt such as NaClO, Ca(OCI)2, bleaching powder or NaBrO, the
sulfamate being present in an amount of 0.5-5 mol per mol hypohalite.
U.S. 4,992,209, February 12, 1991, Smyk et al describes a bactericidal,
fungicidal system having a nitrite-containing corrosion inhibitor, for example
cooling systems, prepared by reacting NaBr with NaOCI or C12 and sodium
sulfamate or sulfamic acid and the product is assertedly "reacted within 5
hours
of preparation".
U.S. 5,431,839, Guillou, July 11,1995 describes sulfamic acid
cleaning/stripping compositions comprising heteropoiysaccharide thickening
agents. U.S. 5,047,164, September 10, 1991, Corby, describes compositions
containing interhalogens and acid especially adapted for cleaning and
disinfecting milk- and food-handling equipment. U.S. 4,279,764, Brubaker, July
21, 1981 describes encapsulated bleaches comprising storage stable
chlorinated isocyanurates. U.S. 4,233,173, Mayer et al, November 11,1980
and U.S. 4,201,687, Crutchfield et a1 describe detergent compositions
containing chloroimidodisuifate bleaching agent. U.S. 5,470,499, Choy et al,
November 28, 1995 describes thickened aqueous abrasive cleansers with
improved rinsability. Commonly assigned U.S. 4,051,056, September 27,
1977, Hartman describes abrasive scouring compositions with perlite and
hypochlorite bleach. Commonly assigned U.S. 3,715,314, Morgenstern,
February 6, 1973 describes scouring cleanser compositions. Commonly
assigned U.S. 5,384,061, Wise, January 24, 1995 describes stable thickened
aqueous bleaching compositions comprising chlorine bleach and phytic acid.
industrial uses of sulfamic acid are included in a literature review, see
"Inorganic Sulfur Chemistry", G. Nickless, Ed., Elsevier, 1968, Chapter 18,
"Amido- and Imido-sulphonic acids", 607-667 and references cited therein; see
CA 02254799 1998-11-13
WO 97/43392 PCT/LTS96/07089
4
also Kirk Othmer Encyclopedia of Chemical Technology, 3rd Ed., Wifey-
Interscience, Vol. 21, "Sulfamic Acid and Sulfamates", pp 949-960.
Chloramines, Bromamines and N-halamines more generally are reviewed in
Kirk Othmer's Encyclopedia of Chemical Technology, Wiley-Interscience, 4th
Ed., Vol. 5, pp 911-932; see also a corresponding article in the 3rd edition
of
the same Encyclopedia. Chlorine gas has previously been mixed with solutions
containing sulfamic acid: see Korshak et al., Zh. Obsch. Khim., Vol. 18
(1948),
pages 753-756, but the mixture decomposed.
SUMMARY OF THE INVENTION
The present invention encompasses a process for manufacturing an alkaline
bleaching composition, preferably an aqueous liquid bleaching composition,
said process comprising at least three stages. These stages include, in
sequence (I) a pre-bromine stage, (II) a bromine compound addition stage, and
(III) a product stabilization stage, and each of said stages has at least one
mixing step.
In said process, said pre-bromine stage, (I), comprises a step, (a), of mixing
in
any order components comprising a hypochlorite source and an
aminofunctional compound having a stable N-halo derivative; thereby forming a
stage (I) mixture; provided that at the end of said pre-bromine stage, said
stage
(1) mixture has a pH not exceeding about 11, preferably lower; said bromine
compound addition stage, {II), is initiated at said pH and comprises a step,
{b),
of mixing in any order with said stage (I) mixture, a bromine compound;
thereby
forming a stage (II) mixture; and said product stabilization stage, (111),
comprises at least one step, (c), of mixing in any order with said stage (II)
mixture, an alkali in an amount suitable to arrive at a final pH for the
product of
said process of at least about 13.
The product provided by this process has unique advantages in terms of
excellent bleaching effect at the same time as permitting a minimization of
"bleach odor" on skin. The preferred product is a transparent yellow aqueous
liquid, which may optionally be thickened andlor perfumed.
CA 02254799 2002-06-18
5
All percentages, ratios. and proportions herein are on a weight basis unless
otherwise indicated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 represents a schematic outline of the present process, showing the
conversion of starting-materials (ingredients) to product via a series of
stages,
comprising, in sequence, Stage (I), Stage (II) and Stage (ill). Each stage, as
indicated, includes one or more steps. Stage (I) includes an essential step,
namely Step (a). Stage (II) includes an essential step, namely Step (b), and
Stage (111) includes an essential Step, namely step (c). The present process
in
the most reduced form which c;an be constructed from Fig. 1 consists of the
sequence of three steps (a) followed by (b) followed by (c). Each of the
essential stages and steps, as well as suitable ingredients and
characteristics
of the product are described in detail hereinafter.
DETAILED DESCRIPTION OF THE INVENTION
In acaxdan ce with the present invention, it has been discovered that in order
to seaxe an alkaline bleaching composition having superior technical
performance and dexirability for the consumer, it is necessary to provide two
distinct types of halogen ingredient including at least one having, at the
outset,
the form of a bromine compound and at least one having, at the outset, the
form of a hypohalite compound. It has also been found essential to
particularly
soled and include a certain aminofundional compound; and to provide a
particular process, especially in tonne of mixing sequence, to secure the
product benefits.
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
6
Alkaline Bleaching Compositions
Accordingly, the present invention relates to processes for making alkaline
bleaching compositions and to the products thereof. "Alkaline bleaching
compositions" as defined herein are strongly alkaline. The "alkaline bleaching
compositions" herein have a pH as is of at least about 13, and are made from
ingredients comprising a hypophalite source and a bromine compound along
with at least one particularly selected aminofunctional compound. Alkaline
beaching compositions herein are useful to the consumer as products for hard
surface cleaning, bleaching or disinfectancy. They can, in general, have any
suitable physical form, such as granular, tablet, paste, gel ar liquid form,
and
can be aqueous or non-aqueous. However, the process herein is especially
well adapted for making aqueous, alkaline, liquid-form or gel-form bleaching
compositions: technical problems of processing are greatest for such
compositions. Unless otherwise noted, embodiments hereinafter which
illustrate the processes and product of the invention therefore relate to the
aqueous liquid forms.
Process Stases
Processes herein generally comprise at least three stages:
(I) a pre-bromine stage;
(II) a bromine compound addition stage, and
(III) a product stabilization stage.
The stages are carried out in the order (I) then (II) then (III). The stages
are
identified in Fig. 1. Each stage includes one or more steps. In a minimum
configuration, the process includes, in Stage (I), step (a); in Stage (II),
step (b),
and in Stage (III), step (c). Additional steps, for example of adding and/or
mixing other ingredients such as perfumes, surfactants and the like, may be
inserted before or after any of the essential steps, provided that they do not
affect the indicated sequence of essential steps and further, that they are
perfomed compatibly with respecting the pH criticaiities described herein.
In more detail, Stage (I), the pre-bromine addition stage, is a stage used to
bring together a hypochlorite source and a particular aminofunctional
compound; Stage (II), the bromine compound addition stage, is a stage used to
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
7
introduce a bromine compound; and stage (III), the product stabilization
stage,
is a stage used to stabilize the product by increasing pH.
Thus the invention encompasses a process for manufacturing an alkaline
bleaching composition, said process comprising at least three stages
including,
in sequence, (I) a pre-bromine stage, (II) a bromine compound addition stage,
and (III) a product stabilization stage, each of said stages having at least
one
mixing step; wherein in said process, said pre-bromine stage comprises a step,
(a), of mixing in any order components comprising a hypochlorite source and
an aminofunctional compound having a stable N-halo derivative; thereby
forming a stage (I) mixture; provided that at the end of said pre-bromine
stage,
said stage (I) mixture has a pH not exceeding about 11; said bromine
compound addition stage is initiated at said pH and comprises a step, (b), of
mixing in any order with said stage (I) mixture, a bromine compound; thereby
forming a stage (II) mixture; and said product stabilization stage comprises
at
least one step, (c), of mixing in any order with said stage (11) mixture, an
alkali
in an amount suitable to arrive at a final pH for the product of said process
of at
least about 13.
Particularly preferred processes herein are restrictive in terms of when the
bromine compound may be added. In preferred processes, no stage other than
(II) and no step other than (b) comprises adding a bromine compound.
Surprisingly, it has been found that adding bromine compound elsewhere in the
sequence has a negative impact on product performance.
Optional Process Steps
The present process can include various optional steps. An optional step
useful herein is illustrated by a dilution step, included in the process after
completion of stage (III). Such a step as a dilution step can in fact be
carried
out either by the manufacturer, or by the user of the product of stages (I),
(II)
and (III). Dilution steps can in general be included in stage (I), stage (II)
or
stage (III) of the present process, though prefereably, dilution is avoided in
those stages. Typically for best storage stability, a dilution step is not
carried
out in the plant, but rather, by the consumer who uses the composition.
Dilution can result in pH variation, typically including pH decrease.
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
8
Other optional steps useful herein include surfactant addition steps, or steps
of
adding or mixing any suitable optional ingredient, such as those identified
under "optional ingredients" hereinafter.
Process Means
Any suitable means may be employed for accomplishing the present process.
Reactors are desirably chemically inert to halogen bleach and strongly
alkaline
conditions, plastics andlor borosilicate glass lined apparatus is desirably
used
both for durability and to minimize contamination of the product by metals.
Reactors need not be designed for operation under pressure provided that
suitable venting is provided. Mixing of ingredients can be accomplished using
any suitable mixer, such as a motor-driven paddle. Alternately, a centrifugal
pump can be used to provide a recirculating jet of product solution, driving
agitation of the mixture. Other useful process means herein include means for
removing vapors from the work environment. Such means include conventional
scrubbers, etc.
Process Conditions
Temperature
In general the present process can be carried out at widely ranging
temperatures. Preferably, each of said steps (b) and (c) is performed at a
temperature in the range from about 5 °C to about 80 °C,
preferably from about
°C to about 45 °C, most preferably at or about ambient
temperature, e.g.,
about 20°C. Highly preferred process herein accomplish all steps in
stages (I),
(II) and (III) at such temperatures. At higher temperatures, there may be an
increased decomposition tendency and at lower temperatures, freezing can be
a problem.
pH's
The present process requires particular limits on pH variation. There is a
general requirement that at the end of the pre-bromine stage and at the
beginning of the bromine stage, the pH of the stage (I) mixture is not in
excess
of about 11. In preferred embodiments, this pH is not in excess of about 8,
more preferably, it lies in the range from about 1 to about 6.9.
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
9
In preferred embodiments, from the end of stage I, the entire process is
conducted at a rising pH. Such rising pH desirably corresponds with a value of
dpH/dt of at least about + 0.1 pH units/min, preferably about + 0.5 pH
unitslmin, or higher.
In such embodiments, it will be appreciated that the instant process contains
a
pH minimum. The position in the overall sequence of the present process of
this minimum is found at the end of stage (I).
Pressure
The present process can be conducted at any convenient pressure. For
example, chlorine gas and alkali can be reacted under pressure, for example
up to about 5 atm., in stage (I) prior to adding the aminofunctional compound;
and the following stages of the process can be conducted at atmospheric
pressure, or even at reduced pressure if scrubbers or condensers are provided
for collecting lost halogen. Preferred processes are conducted at atmospheric
pressure.
Time
The present process can be conducted in batch or continuous mode. Unless
otherwise indicated, illustrations of the process hereinafter are batch-mode.
Times for completion of a batch may in general vary widely. Typically, times
of
about 5 min to about 1.5 hours are typical for each of stages (I) , (II) and
(III).
In preferred embodiments, Stage (II) will allow at least sufficient time to
permit
the bromine compound to substantially dissolve before proceeding with stage
(III). Also preferably, stage (II) is continued until development of a yellow
color
in the stage {II) mixture. In general, the longer process times are associated
with larger-scale processes. It is preferred herein to minimize the overall
reaction time, and in particular, while allowing sufficient time for stage
(II), to
proceed without delay from that stage to the end of stage (III). Moreover, it
is
highly preferred to minimize any time period between the end of step (a) and
the beginning of step (b), and between the end of step (b) and the beginning
of
step (c).
Concentration and Concentration Ratios
The present process can be conducted over a wide range of concentrations of
the ingredients in water. In preferred embodiments, the process is
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
characterized by a dilution factor for the sure of stages subsequent to stage
(I)
which is not in excess of about twofold. In general, concentrations of the
ingredients are adjusted such that the product of stage (/I1), comprises from
about 0.01 °~ to about 10 % Available Chlorine. Also, in terms of
relative
proportions of the ingredients, the present process preferably relies on an
interhalogen ratio [8r] : [0C/-] of from about 10 : 1 to about 1 : 10,
preferably
1:2 to 1:5, wherein (Br] represents total moles Br added into said process
from
said bromine compound and [0C/- ] represents total moles hypochlorite added
into said process from said hypochlorite source. Moreover, the preferred
processes herein employ an amino-halo ratio [A] : (X] of from about 10 : 1 to
about 1 : 10, wherein [A) represents the total of moles of amino moieties of
said
aminofunctional compound used to form said composition and wherein [X]
represents total moles of bleaching halogen, measurable as Available Chlorine,
added into said composition.
Very preferably, said amino-halo ratio is from about 1.0 : 1.0 to about 1.5 :
1Ø
To illustrate, with repect to the above quantities, sulfamic acid, which
contains
one mole of amino moieties per mole of the compound, is easily computed in
the above relation: [A] is simply the number of moles of sulfamate; but to
give
another illustration, when melamine is used, [A] is the number of moles of
melamine used multiplied by the number of moles (which is 3) of amino
moieties contained in any one mole of melamine.
In4redients
HYpochlorite Source
In general, any convenient hypochiorite source can be used in the instant
process. Preferred hypochlorite sources are selected from chlorine,
hypochlorous acid, alkali metal hypochlorites, alkaline earth metal
hypochiorites, the product of mixing a hypochlorite-liberating compound with
aqueous alkali, and mixtures thereof. Suitable hypochlorite-liberating
compounds, in the sense immediately above, are illustrated by
dichloroisocyanuric acid and its sodium salts and hydrates, which hydrolyze
rather readily to release hypochlorite. Highly preferred hypochlorite sources
herein are selected from alkali metal hypochlorites and the product of mixing
said hypochlorite-liberating compound and aqueous alkali.
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
11
Aminofunctional compound
From the thousands of available aminofunctional compounds, the present
invention selects a limited few which are found operative. In processes of the
invention, suitable aminofunctional compounds are those having stable N-halo
derivatives. The term "having a stable N-halo derivative" herein is defined as
"capable of forming an N-halo derivative and it is stable", rather than as
necessarily "possessing a stable N-halo moiety at the inception of the present
process". Suitable aminofunctional compounds meeting the needs of the
present invention are selected from (i) primary aminofunctional compounds
selected from sulfamic acid, alkali-metal sulfamates, alkaline earth
sulfamates,
tetra-alkylammonium sulfamates, and mixtures thereof; (ii) secondary
aminofunctionai compounds selected from secondary amine derivatives having
formula RR'NH or (R")2NH wherein R, R' and R" are organic moieties and
wherein carbon atoms of said organic moieties are bonded covalently to NH;
(iii) sulfonamides selected from sulfamide, p-toluenesulfonamide,
imidodisulfonamide, benZenesulfonamide, alkyl sulfonamides, and mixtures
thereof; (iv) melamine, cyanamide; and (v) mixtures thereof.
Suitable secondary aminofunctional compounds (ii) include those not
specifically identified in (i), (iii), (iv) and (v), wherein R, R' and R" are
independently selected from C1-C12 linear saturated and C3-C12 branched
saturated moieties which can be alkyl, aryl or heterocyclic, optionally
substituted by carboxylic acid or carboxylate: an example of the latter
carboxylic-substituted derivatives is the alpha-aminobutyrates. Preferred
secondary aminofunctional compounds are known for use as disinfectants,
especially those which are water-soluble and those having N-halo derivatives
which are relatively insensitive to shock.
In alternate terms, the present process is believed to be applicable wherever
the aminofunctional compound has a hydrolysis constant, K, as defined by
K=[HOCI][RNH2] I [RNHCI]
or K=[HOCI][RR'NH] I [RR'NCI]
or K=[HOCI][(R")2NH] I [(R")2NC1]
in the range of from about 10 ~ to about 10 -9, provided that no isocyanurate
or chlorinated isocyanurate is included as the essential aminofunctional
compound.
CA 02254799 2002-06-18
O
Hydrolysis constants such as the above are well known in the art and are
defined conventionally. See, for example, Kirk Othmer's Encyclopedia of
Chemical Tectanology, 3rd Ed., Vol. 5, article entitled "Chloramines and
Bromamines", see especially page 567, and Kirk Othmer's Encyclopedia of
Chemical Technology, 3rd Ed., Vol. 3, see especially pages 940-941.
Subject to the abave-identified requirements, preferred secondary
aminofunctional compounds can be selected from those identified in Kirk
Othmer, Encyclopedia of Chemical Technology, 4th. Ed., 1993, pages 918-925
and include compounds. identified under the headings "Organic Chloramines
and Bromamines", "~4liphatic Compounds", "Aromatic Compounds" and
"Heterocyclic Compounds'".
Sulfamic acid or sodium sulfamate are highly preferred aminofunctional
compounds herein.
Alkali
Suitable alkali in the present process is selected from alkali-metal-,
alkaline-
earth-, and tetraalkylamrnonium- oxides, hydroxides, carbonates, bicarbonates,
silicates, phosphates, borates, and mixtures thereof.
Bromine compound
Suitable bromine compounds in the present process are selected from the
group consisting of bromine, water-soluble bromide salts, water-soluble
hypobromits salts, hypobromous acid, and mixtures thereof.
Overall Preferred Combinations of Ingredients
In an overall preferred process herein, said hypochlorite source is selected
from alkali metal hypachlorites and the product of mixing a hypochlorite-
liberating compound and aqueous alkali; said aminofunctional compound is
selected from sulfamic acid, alkali-metal suifamates, alkaline earth
sulfamates,
tetra-aikylammonium sulfamates, and mixtures thereof; and said bromine
compound is selected from the group consisting of water-soluble bromide salts.
Highly preferred herein is a process wherein said hypochiorite source is
sodium hypochlorite, said aminafunctional compound is sulfamic aud; and said
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
13
bromine compound is selected from sodium bromide, potassium bromide and
mixtures thereof.
Ingredients or Impurities Desirably Excluded
The present process and product thereof preferably limits certain compounds
which have been found to adversely affect product stability and effectiveness.
Especially undesirable compounds herein are those aminofunctional
compounds which do not form stable N-halo derivatives. Such compounds
include simple ammonium (NH4+) salts, such as ammonium sulfate; urea;
amino acids such as aspartic acid; and mixtures thereof, any of which may, for
example, produce unpleasant odors of undesirable chloramines. Preferred
herein are processes wherein throughout, and at least in the essential
aminofunctional compound, no ingredient comprises more than about 1 % of
aminofunctional impurity compounds having unstable N-halo derivatives.
Translating this requirement in practical terms, sulfamic acid is commercially
available in a range of grades, certain of which may include urea as an
impurity.
The crystal grade of sulfamic acid, which minimizes urea impurity, is found to
be preferred. fn other process embodiments, the present process is conducted
using starting materials which are all water-soluble that is to say, excluding
insoluble materials such as abrasives, thereby avoiding any tendency for
surface-catalyzed bleach decomposition.
Acids and Bases for pH Adiustment
Any convenient alkali or base can be used herein as a pH-adjusting agent for
increasing pH, and any convenient acid can be used herein as a pH-adjusting
agent for decreasing pH; always provided that such alkali or acid is non-
reactive with hypohalite. Preferred alkalis for pH adjustment include water-
soluble alkalis such as sodium hydroxide, potassium hydroxide or mixtures
thereof, and preferred acids include the common mineral acids such as
sulfuric, hydrochloric or nitric, though sulfuric is preferred in this group.
Alternately relatively weak acids can be used; these include acetic acid.
Examples of bases which knowledgeable practitioners will avoid entirely in the
present process include ammonia because it is chemically reactive with other
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
14
essential ingredients herein for purposes other than pH change, forming, for
example, an undesirable type of chloramine when it reacts with hypochlorite.
In general, any simple mineral acid or base additions in the present process
will be carried out in a manner consistent with preserving the chemical
integrity
of the aminofunctional compound. For example, when using sulfamic acid as
the aminofunctional compound, mineral acid additions are conducted under
sufficient dilution to avoid decomposition of the sulfamic acid. Concentrated
nitric acid, for example, is known to decompose sulfamic acid at HN03
concentrations of 73%, especially at elevated temperatures, with formation of
nitrous oxide, and such combination of concentrated mineral acid and elevated
temperature is avoided in the instant process.
Water
Water used for making liquid compositions according to the present process is
suitably city water. In general, hard, soft, softened or deionized water may
be
used. Distilled or reverse-osmosis treated water are especially desirable.
When using water of uncertain quality, for example ferruginous water or high-
manganese water from boreholes, it is desirable to reduce the dissolved metal
content by conventional water treatment approaches, for example, cv ~7enation,
~Itra . and settling. Moreover a chelant or sequestrant can be us to treat
process water. It is prudent to monitor or periodically check, and if needed,
minimize transition metal ion content of the water by conventional techniques
since transition metal ions are well-known to affect bleach product stabiliy.
Suitable analysis is by atomic absorption spectroscopy or inductively coupled
plasma spectroscopy (1CP).
pH Measurement
pH herein is measured using a glass electrode or combination electrode such
as Corning General Purpose Combination electrode Cat. No. 476530, and a
commercial pH meter such as the ~ 40 pH meter available from Beckman.
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
~H Rampiny
It is desirable, and indeed characteristic of the present process as best
currently known, for there to be present a downward pH ramp (a "ramp" herein
being a relatively linear increase or decrease in pH with time) followed by an
upward pH ramp, there being a strong minimum in the pH as indicated in the
process definition. In the latter part of the process, as noted hereinabove,
the
upward ramp of pH, measurable by dpH/dt, is specifically in a defined range
believed to be linked to stability and performance.
Bleach in4redient measurement: Available Chlorine
The term "Available Chlorine" sometimes abbreviated "AvCl2" as used herein is
described in Kirk Othmer's Encyclopedia of Chemical Technology, Vol. 4, 4th
Ed. (1992) pages 274-275 published by Wiley-Interscience.
Reactions which produce an oxidant from chlorine include the following:
C12(gas) ~ C12 (aqueous)
C12(aqueous) + H20 ~-- ~ HOC/ + H+ + CI-
HOCI ~ H+ + OCI-
RR'NCI + H2p ~- ~ HOC/ + RR'NH
The total concentration or amount of any given chlorine-based oxidant is often
expressed on an equivalent basis, as though all the oxidant were chlorine.
Available Chlorine is thus the equivalent concentration or amount of chlorine
needed to produce an oxidant, for example according to the above reactions,
and can be measured by conventional measures, such as iodometric methods
referenced in Kirk-Othmer (op. city.
Available Chlorine can be calculated from the following relation:
Available Chlorine (%) _
70.9 x moles of oxidant x (number of active CI atoms / molecule) x 100
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
16
In the above relation, the term "active CI atoms" needs definition: Because
C12
only accepts two electrons, as does HOCI and monochloroamines, it has only
one "active" CI atom according to the present definition.
When determining the Available Chlorine expected for product of the instant
process, "moles of oxidant" in the above relation is replaced by "total moles
of
bleaching halogen added in forming the composition".
Note that "Available Chlorine" can be determined for bleaches that do not
actually form hypochlorite in solution, such as bromine-containing bleaches,
and other nonchlorine bleaches, by substituting the number of electrons
accepted divided by two for the number of active chlorine atoms in the above
relation. This can also be measured by iodometric titration.
Note also that the Available Chlorine unit is a dimensioniess percentage, not
a
percentage by weight. It should be apparent from the definition that it is in
fact
possible in general terms to obtain Available Chlorine values which exceed
100%; this can happen in the case of a chlorine bleach which is more mass
efficient than C12, recalling that only one chlorine atom in C12 is a
bleaching
chlorine atom; however, such levels are not encountered in the present
process.
Amounts and Ratios of ingredients
In general, amounts and aqueous concentrations of ingredients herein may
vary quite widely; nonetheless there is a strong preference for particular
interhalogen ratios as defined elsewhere herein and it is commercially
attractive to use ingredients such as sodium hypochlorite at the most economic
concentrations provided by their manufacturers.
Advantages
As noted, the present invention has significant advantages, for example
improved bleaching. By "improved bleaching" it is meant herein that a
composition obtainable with the process of the present invention delivers
better
bleaching performance on bleachable stains like tea stains, as compared to the
bleaching performance delivered by the same composition made by another
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
17
process, for example one involving numerous alternate orders of addition or
mixing of the ingredients. Importantly, concurrent with improved bleaching,
the
formulations provided by the process leave low residual odor on skin and are
w milder than those otherwise manufactured with different ingredient
selections
and/or orders of addition. In short the combination of overall performance and
desirable skin safetylaesthetics offered by the present process are believed
to
be measurably superior to those attainable by any art-recognized process.
Product Characteristics
The product of the present process is not in general limited as to form,
though it
is highly preferred for the compositions produced to be aqueous liquids or
aqueous gels. Another product form potentially preferred herein is a "high-
solubility solid concentrate" or "high solubility tablet" form. Such product
forms
are free from abrasives. The product of the process is preferably transparent,
and, as described elsewhere herein, may be both colored and perfumed.
Processing of Optional Ingredients
The present process and the product thereof allow for the presence of at least
one additional mixing step other than the essential minimum (a), (b), (c);
wherein there is added an ingredient selected from the group consisting of
surfactants, buffers, builders, cheiants, perfumes, colorants, dyes, bleach
stabilizers, pigments, suds supressors, anti-tarnish andlor anti-corrosion
agents, soil-suspending agents, germicides, alkalinity sources, hydrotropes,
anti-oxidants, clay soil removallanti-redeposition agents, thickeners,
solvents,
and mixtures thereof. For other optional ingredients, see U.S. 3,583,922 or
other references cited in the background, recognizing that '922 relates to
solid
compositions as distinct from the liquids herein.
Other ramifications
The present process can accomodate perfumes and colorants, most
particularly known bleach-stable colorants such as various yellows; and
perfumes offering citrus or pine character. Perfumes for use herein are
desirably hydrophobic, having relatively high octanol/water partition
coefficients
such as 6 or above. In process terms, it has been found desirable to
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
18
incorporate perfume in a step which follows (III) (a). Without being limited
by
theory, this is believed to be due to a reduced tendency for reaction of
sulfamate derivatives with perfume aldehydes when they are incorporated late
in the process. Also desirably, bleach-stable thickeners such as those
referenced in background and/or Laponite ~, a special clay available from
Laporte, and/or fatty amine oxides may be combined using the present process
to deliver product having a wide range of useful properties.
Optional Ingredients in More Detail
Optional ingredients are now nonlimitingly illustrated in more detail. Such
ingredients as noted include surfactants, bleach stabilizers, colorants, suds
boosters, suds supressors, anti-tarnish and/or anti-corrosion agents, soil-
suspending agents, germicides, alkalinity sources, hydrotropes, anti-oxidants,
clay soil removal/anti-redeposition agents, polymeric dispersing agents, and
the like; and mixtures thereof.
The processes herein may make use of, based on the composition of the
product, from about 0.1 °~ to about 95% of a surtactant or mixtures
thereof
selected from the group consisting of anionic, nonionic, ampholytic and
zwitterionic surface active agents. For liquid systems, surtactant is
preferably
present to the extent of from about 0.1 % to 20%,. though higher levels, e.g.,
30°~ are possible, for example in viscous gels, aqueous pastes or semi-
solids.
Anionic surtactants herein can include water-soluble salts, particularly the
alkali
metal salts, of Cg-C22 organic sulfuric reaction products and a radical
selected
from the group consisting of sulfonic acid and sulfuric acid ester radicals.
Sodium or potassium alkyl sulfates, especially those obtained by sulfating Cg-
C1g alcohols are useful, as are linear or branched alkyl benzene sulfonates
especially the Cg-C15 alkyl-substituted sodium- or potassium- salt forms; also
useful are the sodium alkyl glyceryl ether sulfonates, especially those ethers
of
the higher alcohols derived from tallow and coconut oil; sodium coconut oil
fatty
acid monoglyceride sulfates and sulfonates; sodium or potassium salts of
sulfuric acid esters of the reaction product of one mole of a higher fatty
alcohol
(e.g. tallow or coconut alcohols) and about 1 to about 10 moles of ethylene
oxide; sodium or potassium salts of alkyl phenol ethylene oxide ether sulfates
with about 1 to about 10 units of ethylene oxide per molecule and in which the
CA 02254799 1998-11-13
WO 97143392 PCT/US96/07089
19
alkyl radicals contain from 8 to 12 carbon atoms; the reaction products of
fatty
acids derived from coconut oil sodium or potassium salts of fatty acid amides
of
a methyl tauride in which the fatty acids, for example, are derived from
coconut
oil; and sodium or potassium beta-acetoxy- or beta-acetamido-
alkanesulfonates where the alkane has from 8 to 22 carbon atoms.
Additionally, conventional primary alkyl sulfates, such as those having the
general formula ROS03 M+ wherein R is typically a linear Cg-C22
hydrocarbon group and M is a water solublizing ration are useful herein, as
are
the secondary alkyl sulfates and/or branched chain primary alkyl sulfate
surfactants (i.e., branched-chain "PAS") having 8-20 carbon atoms, see EP
439,316 A Smith et al. Secondary alkyl sulfate surfactants include those
materials which have the sulfate moiety distributed randomly along the
hydrocarbyl "backbone" of the molecule. Such materials may be depicted by
the structure
CH3(CH2)n{CHOS03-M+)(CH2)mCH3
wherein m and n are integers of 2 or greater and the sum of m + n is typically
about 9 to 17, and M is a water-solublizing ration.
In addition, the selected secondary (2,3) alkyl sulfate surfactants used
herein
may comprise structures of formulas I and II
CH3{CH2)x(CHOSOg'M+)CH3 I
CH3(CH2)y(CHOS03-M+)CH2CH3 II
for the 2-sulfate and 3-sulfate, respectively. Mixtures of the 2- and 3-
sulfate
can be used herein. In formulas I and II, x and (y+1 ) are, respectively,
integers
of at least about 6, and can range from about 7 to about 20, preferably about
to about 16. M is a ration, such as an alkali metal, ammonium,
alkanolammonium, triethanol-ammonium, potassium, ammonium, and the like,
can also be used.
The aforementioned secondary alkyl sulfates are those prepared by the
addition of H2S04 to olefins. A typical synthesis using alpha olefins and
sulfuric acid is disclosed in U.S. Pat. No. 3,234,258, Morris, issued February
8,
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
1966 or in U.S. Pat. No. 5,075,041, Lutz, issued December 24,1991. The
synthesis conducted in solvents which afford the secondary (2,3) alkyl
sulfates
on cooling, yields products which, when purified to remove the unreacted
materials, randomly sulfated materials, unsulfated by-products such as C10
and higher alcohols, secondary olefin sulfonates, and the like, are typically
90
+ % pure mixtures of 2- and 3- sulfated materials (some sodium sulfate may be
present) and are white, non tacky, apparently crystalline, solids. Some 2,3-
disulfates may also be present, but generally comprise no more than 5 % of the
mixture of secondary (2,3) alkyl mono-sulfates. Such materials are available
as
under the name "DAN", e.g., "DAN 200" from Shell Oil Company.
Especially preferred surfactants for use in the present process are those
having
the highest possible bleach stability, including Cg-C22 fatty amine oxides
such
as hexadecyldimethylamine N- oxide or saturated fatty alkyl alkoxylates.
Particularly objectionable surfactants are those having a high degree of
unsaturation, and any surfactants comprising hypohalite-reactive nitrogen
moieties. Somewhat less problematic, but still a potential source of
difficulty,
are the use of any alcohols. Thus, when using alkyl ethoxylates, etc., the so-
called "capped" forms in which terminal -OH is replaced by -OCH3 or similarly
unreactive groups, is particularly preferred.
The most bleach-stable and hydrolytically-stable surfactants can be added at
various stages of the present process, but for convenience, their addition
will
generally be done in such manner as to minimize foaming which may
undesirably slow down the process. Silicone anti-foams are desirable for
limiting foam; such anti-foams are commercially available from Dow Corning
Corp.
When processing a surfactant having susceptibility to acid hydrolysis, such as
an alkyl sulfate, it is incorporated into the product in the present process
at any
point at which the pH of the mixture of ingredients has exceeded about 7,
preferably, when said pH has exceeded about 8.
Although preferred processes and compositions herein are free from insoluble
materials and are non-abrasive, products of the present process can be
formulated in a solid or viscous semi-solid form further comprising an
abrasive
material, such as expanded perlite abrasive in combination with the
surfactants,
CA 02254799 1998-11-13
WO 97/43392 PCT/L1S96107089
21
filler material, or other optional scouring material ingredients listed
herein.
When desired, abrasive materials can be those contained in U.S. Pat. No.
4,051,056, Hartman, issued September 27, 1977.
Other optional ingredients to be used herein include buffers, for purposes
which include to adjust the cleaning surface pH to optimize the hard surface
cleaner composition effectiveness relative to a particular type of soil or
stain.
Buffers may also be included to stabilize the adjunct ingredients with respect
to
extended shelf life or for the purpose of maintaining compatibility between
various aesthetic ingredients. The hard surface cleaner of the present
invention optionally contains buffers to help adjust and maintain the pH at
about 13 or in a range above about 13. Non-limiting examples of such suitable
buffers are potassium carbonate, sodium carbonate, and trisodium phosphate,
however, the formulator is not restricted to these examples or combinations
thereof.
The cleaning compositions obtainable according to the process of the present
invention may also desirably be prepared with inclusion of a heavy metal ion
control system, especially one comprising one or more agents for the control
of
bleach destabilization caused by soluble, insoluble or colloidal iron and/or
manganese andlor copper. A simple but effective agent is sodium
tripolyphosphate, optionally supported by at least partially polymeric hydrous
sodium silicate. Examples of other chelating or heavy-metal control agents are
phytic acid and ethane-1-hydroxy-1,1-diphosphonic acid (EHDP), though other
materials, such as a number of commercial phosphonate types, may be used.
Preferred chelating agents herein, are free from alcohol sites, halogen-
reactive
nitrogen donor sites, and hydrolytically sensitive sites. In process terms, a
preferred addition of at least some chelating agent or heavy-metal ion control
agent takes place at or near the beginning of the process, for example
immediately before, or concurrent with, step I(a). However, when adding a
silicate for the purpose at least in part of helping control heavy metal ions,
it is
added at a point in the process which is remote from both the pH minimum and
the pH maximum of the process.
Perfumes when used are typically at levels of from 0% to 5%. See U.S. Pat.
No. 4,246,129, Kacher, issued January 20, 1981.
CA 02254799 1998-11-13
WO 97143392 PCTIUS96/07089
22
The compositions obtainable according to the process of the present invention
typically have a yellow color. However, it is possible to provide a preferred
solution which has some other color, for example, by the addition of a bleach-
stable dye; moreover, preferred solutions may readily be diluted, in which
case
yellow color is difficult to detect. In process terms, dyes are preferably
added
at the end of the process, in which case product-making can be more
conveniently monitored on a colorant-free product.
The liquid compositions obtainable according to the process of the present
invention may be formulated with different viscosities. In one embodiment of
the
present invention the compositions obtainable with the process herein have a
viscosity of from about 1 to about 150cps. Said compositions are convenient
for
spray bottle application. Likewise, said liquid compositions obtainable
according to the present invention can be further thickened, e.g., by the
addition of additional bleach-stable thickener, such as the commercially
available DOWFAX. A suitable gel formulation has a viscosity of from about
100 cps to about 2000 cps, preferably from 300 cps to 1000 cps as measured,
for example, by techniques and methods described in "Physico-Chemical
Methods", Reilly, J. and Rae, W. N.; Vol. 1 (5th ed.), pages 667-692; D. Van
Nostran pub. Thickeners, when added in the instant process, are desirably
used toward the end of the process, for example, adding them immediately
after, or concurrent with, stage (III).
EXAMPLE 1
(I) Pre-Bromine Sta4e
All operations are conducted at ambient temperature, about 20 °C.
30 grams
distilled water is placed in a chemically inert, plastic-lined reaction
vessel. The
vessel is set for operation at atmospheric pressure and as a precaution is
connected to a scrubber for removing any minor quantity of chlorine vapors
which might be emitted. The vessel is equipped with an inert-plastic-coated
paddle stirrer. While stirring at 300 rpm, 13.05 grams of aqueous sodium
hypochlorite, assayed as comprising 10.73% Available Chlorine, is added.
Immediately thereafter, sulfamic acid (2.2 grams, Aldrich, 99.3%, crystalline)
is
added with continued stirring until the added solid has dissolved. At this
point,
the pH of the stage (l) mixture is about 1Ø
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
23
(II) Bromine Compound Addition Sta4e
To the stirred stage (I) mixture is added Sodium Bromide (0.5 grams, EM
Science). The mixture is stirred until the added solid has dissolved (about 5
minutes) and a yellow color has appeared. The mixture at this point is
identified as a Stage (II) mixture.
L11) Product Stabilization Sta4e
To the stirred stage (II) mixture is added Sodium Hydroxide (about 3.0 grams,
50% in water) until the pH of the mixture is about 13.2.
Water is added until the total weight of the stage (III) mixture is about 100
grams.
EXAMPLE II
The process of Example 1 is repeated with the following differences: The scale
of operations is increased 1000-fold. In a pre-processing step, chlorine gas
is
passed into sodium hydroxide solution, forming sodium hypochlorite solution.
The sodium hypochlorite solution is passed into the above-identified reactor
in
batches, where it is treated with sulfamic acid, forming a stage (1) mixture.
Steps subsequent to stage (I) are conducted in the manner of Example I.
EXAMPLE III
The process of Example II is repeated with the following difference: Sodium
Sulfamate is substituted for sulfamic acid.
In the examples below, a heavy line indicates the boundary separating Stages
(I), (II) and (III) of the process.
EXAMPLE IV
CA 02254799 1998-11-13
WO 97!43392 PCT/US96/07089
24
The process of Example III is repeated with the following difference: prior to
completion of Stage I, aqueous hydrochloric acid is added to reduce the pH to
about 7Ø
EXAMPLE V
Ingredient Addition Seauence %
wt
Hydrous Sodium Silicate(2) 0.20
(Britesil H20, PQ Corp.)
Sodium Tripolyphosphate(3) 0.20
First portion
Sodium Hypochlorite (4) 0.90
Sulfamic Acid (5) 1.30
Potassium Bromide (6) 1.10
Sodium Tripolyphosphate (7) 7.60
Second Portion
Sodium Hydroxide (8) 0.80
Cocodimethylamine N- Oxide(9) 0.25
~Ye ( 10) 0.15
Perfume ( 11 ) 0.60
Water (1 ) and (12) bal.
("bal."means
"balance to 100%"
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
EXAMPLE VI
Inctredient Addition Sectuence % wt
Sodium Hypochlorite (2) 1.4
Sulfamic Acid (3) 1.9
Sodium Silicate (4) 0.04
Sodium Bromide (5) 1,g
Sodium Hydroxide (6) 1.6
Surfactant (7) 3.5
Dyes / perfume (8) 0.28
Water (1 ) and (9) bal.
Note:
""Surfactant" refers to C8 Alkyl Sulfate, C12-C14 Dimethylamine N- Oxide or a
mixture thereof.
EXAMPLE VII
Ingredient Addition Sequence % wt
Sodium Hypochlorite (1 ) 1.4
Sodium Sulfamate / (2) 2.2*"'
Sulfuric acid
Sodium Bromide (3) 1.5
Potassium Bromide (4) 1.1 _
Sodium Silicate (5) 0.05
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
26
Perfume (6) 0.1
Sodium Hydroxide (7) 1.g
Sodium Octyl Sulfate (8) 5.5
Yeliow Dye (9) 0.28
Water (10) bal.
("bal."means
"balance to 100%")
'"' weight equivalent to sulfamic acid content, dry basis
EXAMPLE VIII
Ingredient Addition Seguence wt
Cocodimethylamine N- oxide (1 ) 3.0
Sodium Sulfamate (Sulfuric(2) 0.5'*
acid
Calcium Hypochlorite (3) 0.5
Sodium Dichlorocyanurate (4) 0.50
Potassium Bromide (5) 1.5
Sodium Hydroxide (6) 0.8
Sodium Tripolyphosphate (7) 1.6
Sodium Acetate (8) 0.3
Potassium Hydroxide (9) 0.85
Sodium Octyl Sulfate (10) 3.00
Dyes I perfume ( 11 ) 0.28
Water (12) bal.
"" weight equivalent to
sulfamic acid content,
dry basis
CA 02254799 1998-11-13
WO 97/43392 PCT/US96/07089
27
EXAMPLE IX
Ingredient Addition Sequence wt
Surfactant (2) 6.1
Sodium Dichlorocyanurate(3) 1.2
Melamine (4) 0.23
Potassium Bromide (5) 1.0
Tetrapotassium Pyrophosphate.(6) 13.0
Tripotassium Phosphate (7) 12.0
Sodium Silicate (8) 0.5
Calcium Carbonate (9) 39.0
Calcium Oxide {10) 2.8
Perlite Abrasive (11 ) 22.5
Sodium Hydroxide (12) 1.1
Water (1 ) and (13); bal.
split
1:1 by weight
Note 1:
"'Surfactant" refers to
C8 Alkyl Sulfate, C12-C14
Dimethylamine N- Oxide
or a
mixture thereof.
