FIELD OF THE INVENTION
[0001] The invention pertains to aqueous hypochlorite bleach products which contain optical
brighteners.
BACKGROUND ART
[0002] Sodium hypochlorite is a highly effective bleaching agent and has long been used
in conjunction with soaps and detergents to remove stains and other types of soils
in the laundering of fabrics. It is generally formulated at a concentration of about
4-8% in water for sale for household use, where it is typically diluted to a concentration
of about 200 ppm sodium hypochlorite for laundry bleaching.
[0003] Optical brighteners are dyes which are absorbed by fabrics and impart to the fabric
an added increment of whitenessl brightness by means of their ability to absorb invisible
ultraviolet radiation and re-emit it as visible radiation. Optical brighteners have
been included as a component in laundry products for many years.
[0004] Most optical brighteners are subject to chemical attack by hypochlorite in solution,
and their brightening effect is considerably diminished when used in conjunction with
hypochlorite in laundering of fabrics. However, some optical brighteners have been
developed which are resistant to hypochlorite attack.
[0005] It is desirable to formulate concentrated (typically about 3-8%) sodium hypochlorite
solutions which contain bleach stable optical brighteners. Thus, if the housewife
uses bleach in conjunction with a detergent which contains a brightener which is not
stable to hypochlorite, a fabric brightening effect will still be obtained from the
brightener present in the bleach.
[0006] Optical brighteners are generally insoluble in concentrated hypochlorite, and tend
to quickly settle to the bottom of an aqueous hypochlorite product. Thus, simple addition
of optical brightener to concentrated aqueous hypochlorite results in a product which
must be vigorously shaken each time before use. Because of the tendency for rapid
settling, even vigorous shaking before each use does not necessarily always result
In the obtaining of uniform proportions of brightener and hypochlorite In each use.
U.S. Pat. No. 3,393,153, Zimmerer, issued July 16, 1968, presents a solution to this
problem by including in the composition a particulate material such as colloidal silica
or a particulate colloidal polymeric resin which keeps the optical brightener in suspension
In aqueous hypochlorite.
[0007] U.S. Patent Application Ser. No. 649,457, Hensley & Kitko, filed Sept. 11, 1984,
is directed to the formulation of aqueous sodium hypochlorite compositions containing
a fine dispersion of a bleach stable optical brightener. The compositions comprise
sodium hypochlorite, optical brightener, 4,4'-bis(4-phenyl-2H-1,-2,3-triazol-2-yl)-2,2'-stilbenedisulfonate,
certain alkylaryl sulfonate surfactants, and water. The optical brightener is present
in the composition in the form of a dispersion of fibrous particles having diameters
of from about 0.01 to about 1.5 microns. This type of composition is cloudy.
[0008] It is an object of the present invention to provide a brightened hypochlorite solution
for the laundering of fabrics.
[0009] It was previously theorized that if the said optical brightener was solubilized by
amine oxide, the brightener would be completely destroyed by hypochlorite attack.
[0010] It is an object of the present invention to provice a substantially clear and stable
aqueous compositions containing hypochlorite and optical brighteners.
DETAILED DESCRIPTION OF THE INVENTION
[0011] In accordance with the present invention it has been surprisingly discovered that
the bleach stable optical brightener 4,4'-bis(4-phenyl-2H-1,2,3-triazol-2-yl)-2,2'-stifbenedisulfonic
acid (or its salts) can be solubilized with amine oxide to provide a substantially
clear and stable aqueous sodium hypochlorite brightener solution. There Is substantially
no settling or salting out problem as in the prior art.
[0012] The compositions of the invention comprise:
(a) from 3% to 8% sodium hypochlorite;
(b) from 0.025% to 0.2% of an optical brightener having the formula:

or salts thereof;
(c) from 0.5% to 2% of an amine oxide having the formula:

wherein R1 is a C8-C18 saturated alkyl group and R2 and R3 are C1-C12 saturated alkyl groups; and
(d) at least 80% water.
wherein the amine oxide and brightener are present at a ratio of from 40:1 to 10:1.
[0013] All percentages and ratios herein are "by weight" unless specified otherwise.
Sodium Hypochlorite
[0014] Typically, sodium hypochlorite is commercially available in aqueous solutions having
a concentration of from 5% to
[0015] 15%. These solutions typically contain an equimolar amount of sodium chloride. In
making the compositions of the present invention it is generally desirable to add
sodium hypochlorite solution to the brightener/surfactant solution in volumes such
that the volume of sodium hypochlorite will be from 0.4 to 8 times the volume of the
brightener/surfactant solution. Accordingly, the aqueous sodium hypochlorite source
chosen for preparing a composition of the invention should be one which has a sodium
hypochlorite concentration such that it can be mixed with the aqueous brightener/surfactant
solution within these volume proportions to produce the desired amounts of sodium
hypochlorite, brightener and surfactant in the finished product.
[0016] Sodium hypochlorite is present in the compositions of the . invention at levels of
from 3% to 8%, preferably from 4% to 7%.
Brightener
[0017] The brightener used In the compositions herein is 4,4'- bis(4-phenyl-2H-1,2,3-triazol-2-yl)-2,2'-stilbenedisulfonic
acid', or its salts. The structure of the sodium salt is:

[0018] This optical brightener is available from Mobay Chemical Corporation, a subsidiary
of Bayer AG, under the name Phorwite
R CNA.
[0019] The optical brightener is present in the compositions of the invention at levels
of from 0.025% to 0.2%, preferably from 0.05% to 0.2%, and most preferably from 0.05%
to 0.075%.
Surfactant
[0020] The surfactants used in the present invention are selected from the group consisting
of amine oxides having the following molecular structures:

wherein R
1 is a C
8-C
18 (preferably C
10-C
16) saturated alkyl group; R
2 and R
3 are C
1-C
12 (preferably C
1-C
3) saturated alkyl groups.
[0021] The surfactants are present in the compositions herein at levels of from 0.5% to
2.0%, preferably from 0.8% to 1.5%.
[0022] Preferred amine oxide compositions from a practical stand- - point useful in the
practice of the present invention are the commercially available (1) dimethyl "cocoamine"
oxide (a mixture which is dominated by dimethyl-C
12-C
16 straight chain alkyl amine oxide, more particularly a mixture containing approximately
70% C
12 straight chain alkyl dimethyl amine oxides, approximately 25% C
14 of straight chain alkyl dimethyl amine oxides and approximately 4% C16 straight chain
alkyl dimethyl amine oxides) and (2) N-cocomorpholine oxide, a mixture dominated by
C
12-C
16 straight chain alkyl morpholine oxides (specifically containing approximately 70%
C
12 straight chain alkyl morpholine oxide, approximately 25% C
14 straight chain alkyl morpholine oxide and approximately 4% C16 straight chain alkyl
morpholine oxide). Commercial examples of such amine oxide compositions are: Aromox
DMC-W and Aromox DMMC-W which are 30% aqueous dimethyl cocoamine oxide solutions and
Aromox NCMDW which is a 40% aqueous N-cocomorpholine oxide solution, each of which
is produced by the Armac Division of AKZO of Chicago, Illinois. These materials are
described in Brochure 68011, published by Armour Industrial Chemicals, Chicago, Illinois
60609. Other preferred amine oxides are n-undecyl dimethyl amine oxide and n-tridecyl
dimethyl amine oxide.
[0023] Another commercially available amine oxide is Snyprolam 35 DMO, a dimethyl-C
13-C
15 straight chain amine oxide.
[0024] Examples of other suitable amine oxides are disclosed in U.S. Pat. Nos. 3,684,722,
Hynam et al., issued Aug. 15, 1972, and 4,390,448, Boden et al., issued June 28, 1983.
Optionals
[0025] Optionally, perfumes can be present in the compositions of the invention at levels
of from 0% to 0.5%, preferably from
[0026] 0.05% to 0.3%. The perfume materials used should, of course, have a high degree of
chemical stability to sodium hypochlorite. Some preferred materials for use as perfume
ingredients in the compositions herein are patchouli oil, cyclopenta- decanolide,
p-tertiarybutyl cyciohexyl acetate, tetrahydromycenol, tetrahydrolinalool, phenylacetaldehyde
dimethylacetal, methylphenyl carbinol, and mixtures thereof.
[0027] Some perfume materials have been found to function as antifoamants for the compositions
herein, thereby facilitating processing and high-speed packing of the compositions.
Examples of such perfume materials are:
2,6-dimethyloctan-2-ol,
3,7-dimethyloctan-3-ol,
2,6-dimethylheptan-2-ol,
2,4,4-trimethylpentan-2-ol,
2,4,4,6,6-pentamethylheptan-2-ol,
1-methyl-4-isopropylcyclohexan-8-of,
4-tertiarybutylcyclohexyl acetate,
4-tertiarypentylcyclohexyl acetate,
diethylphthalate,
phenylacetaldehyde dimethyl acetal, and
mixtures thereof.
[0028] When perfumes are used in the compositions herein they are preferably mixed into
the solution of brightener and surfactant prior to the addition of aqueous sodium
hypochlorite to the solution.
[0029] If perfume usage is toward the upper end of the usage range (i.e., 0.3% to 0.5%)
then it is usually necessary to use an amount of surfactant which is also at the higher
end of the 0.5% to 2% surfactant usage range hereinbefore disclosed.
[0030] Organic oils other than those mentioned under examples of perfume materials can also
be used in order to mask the chlorine smell. A preferred organic oil is linear alkylbenzene
(LAB) having alkyl chains of from 10 to 14 carbon atoms.
[0031] Other dyes can also be added to the compositions if desired.
Composition Preparation
[0032] The compositions of the invention can be prepared by first preparing an aqueous solution
containing the brightener and the surfactant;
[0033] If perfume is to be used in the composition, it is added to the aqueous solution
of brightener and surfactant.
[0034] For best chemical stability, the compositions herein should - have a pH above 12,
preferably about 12.5. The pH of the composition should be tested after preparation
Is complete. If needed, pH adjustment can be made with acid or base (e.g., HCI or
NaOH).
[0035] The invention will be illustrated by the following example.
EXAMPLE I
[0036]

The brightener is dissolved in distilled water, gently heating if required. The surfactant
Is added with stirring. Then the diluted bleach is added. The brightener is completely
dissolved. The composition is visibly clear and surprisingly exhibits UV fluorescence
on fabrics washed therein. The composition was stored for several months and UV fluorescence
was seen on fabrics washed therein.
1. An aqueous composition comprising:
(a) from 3% to 8% sodium hypochlorite;
(b) from 0.025% to 0.2% of an optical brightener having the formula:

or salts thereof;
(c) fran 0.5% to 2% of an amine oxide having the fornula:

wherein R1 is a C8-C18 saturated alkyl group and R2 and R3 are C1-C12 saturated alkyl groups; and
(d) at least 80% water.
wherein the amine oxide and brightener are present at a ratio of from 40:1 to 10:1.
2. A composition according to claim 1 wherein the amount of sodium hypochlorite in
the finished composition is from 4% to 7%.
3. A composition according to either one of claims 1 and 2 wherein the amount of surfactant
in the finished composition is from 0.8% to 1.5%.
4. A composition according to any one of claims 1-3 wherein the amount of optical
brightener in the finished composition is from 0.05% to 0.2% and said ratio of amine
oxide to brightener is from 30:1 to 20:1.
5. A composition according to claim 4 wherein the amount of optical brightener in
the finished composition is from 0.05% to 0.075%.
'6. A composition according to any one of the preceding claims wherein said amine
oxide is dimethyl-C13-C15 linear alkyl amine oxide.
7. A composition according to any one of the preceding claims additionally comprising
up to 0.5% of a perfume material which is stable against chemical attack by sodium
hypochlorite.