[0001] This invention relates to a detergent composition which has improved soil removal
and/or anti-redeposition properties and provides a process for producing the same.
[0002] Synthetic detergent compositions have been used commercially for a number of years
for the removal of soil from fabric and these compositions generally comprise a number
of different types of compounds or additives. Typically, this type of composition
may include, although not necessarily be limited to: an organic detergent compound
such as a surfactant or surface active agent; a builder component such as a phosphate
salt which enhances the cleaning effectiveness of the surfactant by sequestering various
metallic ions found in hard water; and finally a soil suspending or anti-redeposition
agent to help the surfactant hold the soil particles in suspension and prevent them
from being redeposited onto the fabric during washing.
[0003] The use of a soil anti-redeposition agent generally improves the whiteness of fabrics
washed with the detergent composition since the anti-redeposition agent suspends the
soil in the solution once it has been removed from the fabric and prevents its redeposition
onto the washed fabric. If the detergent composition has poor soil suspension properties
during washing and the soil is allowed to be redeposited, or settle from the wash
onto the washed fabric, the fabric will eventually acquire a gray appearance which
represents an extremely undesirable result for a detergent.
[0004] A number of materials have been proposed for use as soil anti-redeposition agents
but the most widely used material is carboxymethylcellulose, which has been added
for a number of years to different types of detergent compositions used for the washing
of fabrics to prevent redeposition of soil from the solution once the soil has been
removed from the fabric by washing. Other materials which have been proposed as soil
anti-redeposition agents include polyvinyl acetate, polyvinyl alcohol, sodium alginate
and various modified starches, all of which are generally considered to be less effective
than carboxymethylcellulose. Other types of soil anti-redeposition agents which have
been described as having improved soil anti-redeposition properties over carboxymethylcellulose
include polyvinylpyrrolidone (as described in U.S. 3,000,830) and a combination of
carboxymethylcellulose and a gelatin protein (as described in U.S. 3,594,324). While
the use of these materials as soil anti-redeposition agents in detergents has been
successful, nevertheless a need still exists for an improved material having better
soil anti-redeposition properties and one which is readily adaptable and useful in
a wide variety of detergent compositions.
[0005] We have now discovered a soil removal and anti-redeposition agent which has improved
properties, yet which is.convenient to use and readily adaptable to most detergent
compositions.
[0006] The present invention thus consists in a detergent composition including, as an anti-redeposition
agent, a carboxymethylated soy polysaccharide material.
[0007] This detergent composition is particularly suited for the washing of fabrics and
has improved soil removal and anti-redeposition properties over detergent compositions
of the prior art. The detergent composition of the present invention thus comprises
at least an organic detergent compound and the carboxymethylated soy polysaccharide
material, which is preferably the soy polysaccharide or "spent flake" fraction derived
from soy isolate processing, and will normally also include a detergent builder. The
carboxymethylated soy polysaccharide material is added to said detergent composition
in an amount effective to improve soil removal and/or prevent soil redeposition on
fabric which has been washed with the detergent composition.
[0008] It has specifically been determined that the carboxymethylated soy polysaccharide
material developed in the present invention has better soil anti-redeposition properties
in detergent compositions typically used for the washing of fabric than carboxymethylcellulose
which has been added by the prior art to detergent compositions for preventing the
redeposition of soil during washing.
[0009] A similar carboxymethylated soy polysaccharide material is disclosed in Japanese
Patent Application Kokai No. 128658/78.
[0010] The material which is employed in the production of the soil anti-redeposition agent
used in the detergent composition of the present invention comprises a soy polysaccharide
material which itself comprises a mixture of residual high molecular weight sugars
and protein and is normally obtained by the removal of soluble proteins and carbohydrates
from soy flakes, meal or flour; the heterogeneous polysaccharides contained therein
are principally cell wall structural components of the soybean cotyledons. This material
is typically obtained as a by-product from the manufacture or production of a soy
protein isolate and has hitherto been regarded as a waste or, at best, very low value
product. The soy polysaccharide product has also been sometimes characterized as the
aqueous alkaline- insoluble residue or "spent flake" fraction from soy isolate processing.
[0011] In order to illustrate the manner in which the soy polysaccharide material is obtained
from a typical process for the production of a soy isolate, the soybean starting material,
such as soy flakes, meal or flour, is dispersed in an aqueous medium and the pH of
the medium is adjusted to a value of at least 6.0, more commonly at least 7.0. The
flakes, meal or flour is then washed with an aqueous alkaline solution and subjected
to centrifugation. The soluble carbohydrate and protein components are dissolved in
the aqueous extract and the solid residue comprises the bulk of the soy polysaccharide
material in the soy flakes. This solid residue is sometimes referred to as the "spent
flakes" residue and would be typically discarded as a waste product in a soy isolate
process. The alkali-insoluble residue or solids is then customarily subjected to a
second extraction with an aqueous alkali solution to exhaustively extract residual
protein, after which all aqueous extracts containing soluble carbohydrates and protein
are combined for further processing and subsequent acid reprecipitation of the protein
isolate. The residual product from the extraction of soluble carbohydrates and protein
may then be cooked, dried or further processed, for example, to remove extraneous
material if desired. This soy polysaccharide product or fraction, after it has been
dried, is the preferred starting material for making the soil anti-redeposition agent
of the present invention.
[0012] The above description represents only a typical process for obtaining a soy polysaccharide
material and the present invention is not intended to be limited by any specific process
or manner of obtaining the soy polysaccharide material or spent flake fraction which
can be used as a starting material in the present invention. The production of the
soy polysaccharide material represents a conventional process known to those skilled
in the art for the separation of protein material from soy flour, flakes or meal and
other soy products.
[0013] The soy polysaccharide material or spent flake fraction has a typical analysis after
drying of: total carbohydrate content about 80% by weight; protein content about 12
to 16% by weight; and ash content about 4% by weight. This soy polysaccharide material
generally comprises the many high molecular weight carbohydrate polymers contained
in soybeans and, as previously noted, is normally used as a collective term to describe
the fibrous carbohydrate material obtained from the cell wall structural components
of soybeans, including soy flakes or meal.
[0014] The soy polysaccharide material or spent flake fraction is preferably dried and ground
prior to formation of the soil anti-redeposition agent which is used in the detergent
composition of the present invention. Although the exact particle size to which the
soy polysaccharide material is ground is not critical to the practice of the present
invention, it is preferred for purposes of forming the carboxymethylated soy polysaccharide
material that the soy polysaccharide material be ground to a particle size such that
substantially all of it will pass a 100 mesh screen (Tyler). Furthermore, although
the exact moisture level for the soy polysaccharide fraction is not critical to carrying
out the carboxymethylation reaction, it is preferred that the soy polysaccharide fraction
or material should, as previously noted, be dried, preferably to a moisture content
which does not exceed about 12% by weight and preferably is between 6 and 10% by weight
of the material.
[0015] The present invention is not intended to be limited by the exact manner in which
carboxymethylation of the soy polysaccharide material is carried out since a variety
of conditions, reactants and equipment are well known to those skilled in the art.
[0016] A preferred method of producing the carboxymethylated soy polysaccharide material
is to add the ground, dried, soy polysaccharide fraction to an aliphatic alcohol,
preferably a C
1-C
6 alcohol, more preferably a C
1-C
4 alcohol, such as methanol, ethanol, isopropanol or butanol, which acts as a reaction
diluent, and preheat the mixture to a temperature of from 30 to 60°C, with mixing.
The weight ratio of alcohol to polysaccharide material is preferably from 3:1 to 12:1
and more preferably about 7:1.
[0017] Sufficient alkali, such as sodium or potassium hydroxide, is then preferably added
to provide a mole ratio of alkali to cellulose (single glucose unit) which is preferably
from 1.0:1 to 3.0:1. This is followed by the addition of a carboxymethylating agent,
such as monochloroacetic acid or suitable salt thereof, preferably in a mole ratio
to cellulose of from 0.4:1 to 0.8:1.
[0018] The entire reaction mixture is preferably continuously agitated at a temperature
of from 30 to 60°C, preferably for a period of from 1 to 8 hours, in order to provide
substantial carboxymethylation of the soy polysaccharide material. Following formation
of the carboxymethylated soy polysaccharide material, the solids and reactants may
be removed by washing with an alcohol (such as those exemplified above). The carboxymethylated
soy material may be concentrated by filtration or centrifugation. The concentrated
carboxymethylated soy material is then preferably dried in a conventional manner to
form a product suitable for mixing with a detergent composition.
[0019] Since the reaction is usually and preferably effected in the presence of an alkali,
the product will, in most cases, be the salt of the carboxymethylated soy polysaccharide
material. This salt is preferably an alkali metal salt, particularly the sodium or
potassium salt, although many other salts are possible. The sodium salt is generally
most convenient.
[0020] The detergent composition of the present invention is then formulated in the same
way as conventional detergent compositions but employing the carboxymethylated soy
material as the anti-redeposition agent in place of carboxymethylcellulose or other
conventional agent. The detergent composition of the invention employs at least an
organic, normally synthetic, detergent substance or surfactant which can be an anionic,
nonionic, ampholytic or zwitterionic surfactant. A single one of these or two or more
in combination may be employed to produce a detergent composition of the present invention.
[0021] The anionic organic detergent compounds or anionic surface active agents can include
detergent compounds which contain an organic hydrophobic group and an anionic solubilizing
group. Typical examples of anionic solubilizing groups are the sulphonate, sulphate,
carboxylate and phosphate groups. Examples of suitable anionic detergents which could
be used in the invention include the water-soluble salts of higher fatty acids or
resin acids, such as may be derived from fats, oils and waxes of animal or vegetable
origin, and the sulphated and sulphonated synthetic detergents. Also included within
the class of suitable organic detergent compounds are the synthetic anionic detergents
such as the higher alkyl aryl sulphonates (e.g. the higher alkyl benzene sulphonates)
as well as the sulphates of higher alcohols, such as sodium lauryl sulphate.
[0022] Nonionic synthetic detergent compounds do not ionize in solution and the whole molecule
acts as the cleaning agent. Amongst the compounds which can be used in the present
invention are those which can be broadly defined as compounds produced by the condensation
of alkyl oxide groups (which are hydrophilic in nature) with an organic hydrophobic
compound (which may be aliphatic or alkylaromatic in nature). The most widely used
class of nonionic synthetic detergents includes those which are formed by condensing
ethylene oxide or propylene oxide with a hydrophobic base. However, other suitable
nonionic organic synthetic detergent compounds include the polyethylene oxide condensates
of alkylphenols, as well as condensation products of materials such as ethylene oxide
and the product resulting from the reaction of propylene oxide and ethylene diamine,
the condensation product of aliphatic alcohols with ethylene oxide, long chain tertiary
amine oxides and long chain alkyl phosphates.
[0023] Ampholytic synthetic detergent compounds are mainly derivatives of aliphatic secondary
or tertiary amines. An example of a specific compound within this general grouping
is sodium 3-dodecylaminopropionate. Ampholytic surfactants have both positive and
negative centres and can assume either a positive or negative charge depending on
the pH of the solution.
[0024] Zwitterionic synthetic detergent compounds behave somewhat like nonionic surfactants
and most are derivatives of aliphatic, araliphatic and aromatic quaternary ammonium,
phosphonium and sulphonium compounds. Examples of specific compounds falling within
this definition are N-hexadecyl-N,N-dimethyl-N-propylammonium sulphonate and benzyl
and phenyl analogues thereof, such compounds being especially preferred for their
detergent characteristics in relatively cool water.
[0025] The above general groupings of organic detergent compounds may be used singly or
in combination in the practice of the present invention. These represent specific
illustrations of many of the numerous organic detergent compounds or surfactants which
can find application within the scope of the present invention.
[0026] The present invention is further not intended to be limited to the physical form
of the detergent composition since it can be made into any of several commercially
desirable physical forms including powder, granular, flake, liquid and tablet forms.
[0027] The detergent composition of the present invention can further include conventional
ingredients to improve other properties of the detergent composition. Included within
this grouping of materials are the compounds described typically as water-soluble
builder salts, such as phosphates, which are added to enhance the cleaning power of
the detergent composition. Furthermore, various other materials may also be present,
for example, materials to improve the detergency of the composition and to modify
its foaming properties in whatever manner desired as well as other conventional additives,
such as various optical brightening agents and fluorescent whitening agents. Germicidal
ingredients may also be added to improve the overall cleaning or disinfecting properties
of the detergent composition of the present invention. The present invention is not
intended to be limited by the exact contents of the detergent composition of the present
invention since numerous materials are well known and well within the knowledge of
those skilled in the art in the production of detergents.
[0028] Included as an essential ingredient of the detergent composition of the present invention
is the carboxymethylated soy polysaccharide fraction as a soil removal and/or anti-redeposition
agent. The carboxymethylated soy polysaccharide fraction is added to the detergent
composition in an amount effective to improve soil removal and substantially prevent
soil redeposition on fabric during its washing with the detergent composition. Typical
amounts of carboxymethylated soy polysaccharide fraction to be used are from 0.5 to
5% (dry weight) of the detergent composition and more preferably from 1 to 2% (dry
weight) of the detergent composition. The use of the carboxymethylated soy polysaccharide
fraction developed in the present invention has been shown to result in a detergent
composition which has improved soil anti-redeposition properties over detergent compositions
which contain conventional soil anti-redeposition agents such as carboxymethylcellulose
or other soluble polymeric materials.
[0029] The following examples are given to illustrate specific embodiments of the present
invention and specific improvements achieved therewith.
EXAMPLES
[0030] A soy polysaccharide material was obtained by forming an aqueous slurry of 100 lb
(45 kg) of defatted soy flakes and adding thereto 1000 lb (453 kg) of water at 90°F
(32°C). Sufficient calcium hydroxide was added to adjust the pH of the mixture to
a value of 9.7. The soy flakes were extracted for 30 minutes, after which the aqueous
solution containing dissolved protein and carbohydrates was separated from the extracted
flakes by centrifugation. The extracted flake residue was then redispersed in 600
lb (272 kg) of water at a temperature of 90°F (32°C) and extracted for an additional
15 minutes. The extracted flakes were then removed by centrifugation from the mixture
and the aqueous extracts were combined for the subsequent production of a soy protein
isolate. The extracted or spent flakes were then dried to a moisture content of 9%
by weight at an air temperature of 180°F (82°C) to produce a soy polysaccharide material
used in preparing the soil removal and anti-redeposition agent of the present invention.
[0031] 415 grams of the dried soy polysaccharide material were then added to 3.8 litres
of isopropanol and the mixture was heated to 40°C with agitation. 375 grams of a 50%
by weight aqueous solution of sodium hydroxide and 125 grams of monochloroacetic acid
were added simultaneously to the reaction mixture over a 30 minute period, with constant
agitation. The reaction mixture was then continuously agitated and maintained at a
temperature of 40°C for an additional 3.5 hours.
[0032] The reacted solids were removed from the mixture by filtration and dried at 190°F
(88°C). This resulted in 500 - 600 g of carboxymethylated soy polysaccharide material.
[0033] The carboxymethylated soy polysaccharide material was then added to the following
detergent composition at a level of 1% or 2% by weight of the composition (the amount
of sodium sulphate was correspondingly 3% or 2% by weight).
Detergent Composition
[0034]

[0035] The detergent compositions containing the carboxymethylated soy polysaccharide material
were then evaluated for effectiveness in preventing the redeposition of soil on fabric
during washing.
[0036] We used a Terg-O-Tometer Apparatus manufactured by United States Testing Company,
Inc., which is a small scale, multiple unit washing machine that simulates the action
of the agitator-type home washer. Swatches of fabrics were washed in the machines
to determine a soil redeposition index.
[0037] Two different types of fabric were employed, a 100% cotton cloth and a dacron (trade
mark)/cotton cloth with permanent press finish. Each cloth used had dimensions of
4 inches x 4.5 inches (10 x 11.5 cm).
[0038] For each test, soiled cloths of the above dimensions were washed between 1 and 5
times and the % soil removal and redeposition index were measured after each wash.
[0039] Wash time was 15 minutes, with two separate 2 minute rinses, a rinse temperature
of 100°F (38°C) and a machine speed of 125 cycles/minute. The water had a hardness
of 150 ppm and the detergent concentration was 0.15% by weight.
[0040] The heating bath of the Terg-O-Tometer was filled with water, the heaters were turned
on, and the thermostat was adjusted to hold the bath at the required temperature.
Solutions of the desired water hardness were prepared. They were heated to a temperature
about 5°F (3°C) higher than that required for the test.
[0041] The soiled and unsoiled cloths were placed in the detergent solution and washed,
the fabric was squeezed by hand after each rinse cycle. After the last rinse, the
cloths were dried and ironed, if necessary. The reflectance of each cloth had previously
been measured prior to washing using a Photovolt Reflectometer Model 670 equipped
with a green filter. Following washing, the reflectance of each cloth was measured
again. Soil removal is calculated for each cloth from the following:
A = Average reflectance of soiled cloth after washing.
B = Average reflectance of soiled cloth before washing.
C = Average reflectance of unsoiled cloth without washing.
[0042] The higher the percentage of soil removal, the better is the soil removal ability
of the product.
[0043] The soil redeposition index is calculated for each cloth by the following:
RA = Average reflectance of soiled cloth after test.
RB = Average reflectance of unsoiled cloth before test.
[0044] This represents the ability of the detergent to hold in suspension the soil that
has been removed by washing. The higher the value, the better the product performance.
[0045] Employing the above test procedure, the detergent composition set forth above was
tested containing 1% by weight carboxymethylated soy polysaccharide and compared against
a control detergent which contained 1% by weight of carboxymethylcellulose in place
of the carboxymethylated soy polysaccharide.
[0046] These results are set forth in Tables 1 and 2.

[0047] It may be seen from the above data that the carboxymethylated soy polysaccharide
was significantly better than the carboxymethycellulose both for soil removal and
in preventing the redeposition of soil.
1. A detergent composition including, as an anti-redeposition agent, a carboxymethylated
soy polysaccharide material.
2. A detergent composition according to Claim 1, wherein said carboxymethylated soy
polysaccharide material is present in an amount of from 0.5 to 5.0% by weight of the
detergent composition on a dry basis.
3. A detergent composition according to Claim 2, wherein said carboxymethylated soy
polysaccharide material is present in an amount of from 1 to 2% by weight of the detergent
composition on a dry basis.
4. A detergent composition according to any one of the preceding Claims, wherein said
carboxymethylated soy polysaccharide material is obtained by carboxymethylation of
a soy polysaccharide material having a moisture content that does not exceed 12% by
weight.
5. A detergent composition according to Claim 4, wherein said soy polysaccharide material
has a moisture content which is from 6 to 10% by weight of the material.
6. A detergent composition according to any one of the preceding Claims, wherein the
soy polysaccharide material that is carboxymethylated has a total carbohydrate content
of about 80% by weight.
7. A detergent composition according to any one of the preceding Claims, wherein the
soy polysaccharide material that is carboxymethylated has a protein content of from
12 to 16% by weight.
8. A detergent composition according to any one of the preceding Claims, wherein the
soy polysaccharide material that is carboxymethylated has an ash content of about
4% by weight.