Technical Field
[0001] The present invention relates to low pH, granular laundry detergent compositions.
Certain preferred compositions herein contain a low level of a chlorine scavenger,
preferably an ammonium salt. The compositions minimize fading of fabric colors sensitive
to higher wash water pHs and to the low levels of chlorine present in the wash and
rinse water. Other preferred compositions herein are dense, low or no phosphate detergents
containing a specific aluminosilicate, citric acid and carbonate builder system. These
compositions provide good cleaning performance while maintaining good physical properties.
Background Art
[0002] Granular laundry detergents typically are formulated to provide a wash water pH of
about 9.8 to 10.5. This pH range can cause fading of some fabric dyes after multiple
laundry cycles. When the wash solution is diluted in the rinse, the pH is lowered
to a range of about 7 to 9 where some fabric dyes are generally less sensitive to
pH.
[0003] Chlorine is used in many parts of the world to purify water. To make sure that the
water is safe, a small residual amount, typically about 1 part per million (ppm),
of chlorine is left in the water. It has been found that even this small amount of
chlorine can cause fading of chlorine-sensitive fabric dyes. In a typical wash, there
is usually enough soil on the fabrics to scavenge residual chlorine and minimize damage
to chlorine-sensitive dyes. However, in the rinse the soil levels are greatly reduced,
as is the pH, and chlorine-sensitive dyes can fade after multiple laundering cycles.
Chlorine is also more aggressive to dyes at the lower pHs. Thus, fading of fabric
colors over time is a result of both the high pH of typical granular laundry detergents
and the presence of residual chlorine in the wash and rinse water.
[0004] Delivering good cleaning performance from a low or no phosphate condensed detergent
is difficult due to limitations in conventional spray dry processing. Additionally,
trying to compensate with higher levels of actives (surfactant and builder) is limited
without significantly diminishing product physical properties (solubility, lumping/caking,
scoopability).
Summary of the Invention
[0005] The present invention encompasses granular laundry detergent compositions comprising,
by weight:
(a) from about 15% to about 25% of a mixture of a C₁₁-C₁₃ alkylbenzene sulfonate surfactant
and a C₁₂-C₁₆ alkyl sulfate surfactant in a weight ratio of sulfonate surfactant to
sulfate surfactant of from about 4:1 to about 1:1;
(b) from about 1% to about 3% of an alkali metal silicate having a molar ratio of
SiO₂ to alkali metal oxide of from about 1.0 to about 2.4;
(c) from about 20% to about 30% of a finely divided aluminosilicate ion exchange material
selected from the group consisting of:
(i) crystalline aluminosilicate material of the formula:
Naz[(AlO₂)z.(SiO₂)y].xH₂O
wherein z and y are at least 6, the molar ratio of z to y is from 1.0 to 0.5 and x
is from 10 to 264, said material having a particle size diameter of from about 0.1
micron to about 10 microns, a calcium ion exchange capacity of at least about 200
mg CaCO₃ eq./g and a calcium ion exchange rate of at least about 2 grains Ca⁺⁺/gallon/minute/gram/gallon;
(ii) amorphous hydrated aluminosilicate material of the empirical formula:
Mz(zAlO₂.ySiO₂)
wherein M is sodium, potassium, ammonium, or substituted ammonium, z is from about
0.5 to about 2 and y is 1, said material having a magnesium ion exchange ion exchange
capacity of at least about 50 milligram equivalents of CaCO₃ hardness per gram of
anhydrous aluminosilicate and a Mg⁺⁺ exchange rate of at least about 1 grain/gallon/minute/gram/gallon;
and
(iii) mixtures thereof;
(d) from about 4% to about 10% of citric acid;
(e) from about 5% to about 20% of an alkali metal carbonate; said composition having
a pH of from about 7 to about 9.3 at a concentration of 1% by weight in water at 20°C,
and said composition having a density of from about 500 to about 600 grams per liter.
[0006] Preferably, the present compositions also contain a chlorine scavenger employed in
an effective amount to control residual chlorine in the wash and rinse water. The
amount of chlorine scavenging material needed will vary, but only a small amount is
used to avoid destroying hypochlorite bleach that may be added deliberately to treat
bleach-sensitive stains.
Detailed Description of the Invention
[0007] The granular laundry detergent compositions of the present invention are formulated
to provide a pH of from about 7 to about 9.3, preferably from about 8 to about 9.1,
more preferably from about 8.5 to about 9.0, at a concentration of 1% by weight in
water at 20°C. The individual components of the compositions herein are described
in detail below.
Chlorine Scavenger
[0009] When present in the compositions of the invention chlorine scavengers should not
be used in a large excess since they will interfere with normal hypochlorite bleaches
added to the wash water for stain removal and whitening. The level should be from
about 0.01% to about 10%, preferably from about 0.05% to about 5%, most preferably
from about 0.08 to about 2%, based on the molar amount equivalent to react with about
0.5 to about 2.5, typically about 1, ppm of available chlorine, per average rinse.
If both the cation and the anion of the scavenger react with chlorine, which is desirable,
the level is adjusted to react with an equivalent amount of available chlorine.
[0010] Suitable chlorine scavengers include the following polymers which can be divided
into four groups according to their structural construction: polyethyleneimines, polyamines,
polyamineamides and polyacrylamides, of which the polyethyleneimines, the polyamines
and polyamineamides are especially preferred.
[0011] Suitable polyethyleneimines are obtained by acid-catalyzed polymerization of ethyleneimine
and can be modified by urea and epichlorhydrin or dichlorethane. Polyethyleneimines
can contain primary, secondary or tertiary amino groups as well as quaternary ammonium
groups. Aqueous solutions of polyethyleneimines show basic reaction. The molecular
weight can amount up to about 1,000,000.
[0012] Polyamines are addition or condensation products from multivalent aliphatic amines
and compounds with several groups capable of reacting, for example, epichlorhydrin
or alkylene dihalides. Therefore, they always contain several secondary, tertiary
or even quaternary nitrogen atoms, as well as eventually also hydroxyl groups in the
molecule. They are accordingly hydrophilic, polar compounds, which behave as polyelectrolytes
and are water soluble, inasmuch as they do not contain large hydrophobic groups in
the molecule. The polyamines exhibit basic reaction in aqueous solution. Suitable
compounds, for example, are described in U.S. Patent 2,969,302.
[0013] Polyamineamides contain amino- and amido groups in the molecule at the same time.
They are made, for example, by condensation of multibasic acids, for example, dibasic,
saturated, aliphatic C₃ to C₈ acids and polyamines, as well as with compounds, which
contain several groups capable of reacting, such as, for example, epichlorhydrin.
These compounds also demonstrate basic reaction in aqueous solution. Suitable polyamineamides
are described, for example, in U.S. Patent 2,926,154.
[0014] Polyacrylamides having amino groups and molecular weights up to several million are
suitable for use herein. By building in carboxyl groups, which are formed, for example,
by partial hydrolysis, anionic polyacrylamides are obtained in addition to amido groups,
while polyacrylamides containing amino groups exhibit basic reaction in aqueous solution.
Amino groups can be introduced, for example, by reaction with alkali and hypobromite
or hypochlorite.
[0015] It is common to all polymers that they are water soluble. Such polymers are commercial
products. Compounds especially well suited as inserts to the detergents conforming
to the discovery are the polyethyleneimines and polyamines, which exhibit strong basic
reaction in water. Examples of commercially available polyethyleneimines, which are
particularly appropriate, are "Epomin SP-003" from Nippon Shokubai, "Lugalvan G20
and G35" from BASF, and "Ethyleneamine E-100" from Dow Chemical. These polymers can
be added either alone or together with water soluble polymers from melamine or urea
and formaldehyde. Other polymers suitable for the detergents conforming to the discovery
are, for example, the water soluble polymers based on alkyleneimines, acrylamides
as well as melamine or urea and formaldehyde, which are described in the "Encyclopedia
of Polymer Science and Technology, John Wiley & Sons, Inc., New York, 1968, Vol. 9,
p. 762. An addition of these polymers to the detergents conforming to the discovery
in combination with the amino- and/or amido group-containing polymers causes an intensification
of the dye-protective effect.
[0016] Preferred polymers for use in the preferred anionic surfactant containing compositions
herein are polyethyleneimines. Polyethyleneimines are believed to be particularly
efficient chlorine scavengers because they adsorb to cotton fibers. In an anionic
surfactant matrix, ion pairing of the amines with surfactant or polymeric carboxylates
tends to dramatically lower the solubility of the polymeric amine. The solubility
of the polymeric amine complexes can be maintained by utilizing materials of relatively
low molecular weight. The molecular weight of the chosen amine polymer should be controlled
to achieve a fabric substantivity of preferably at least 50%. A low substantivity
will not allow efficient carryover into the rinse. Preferred polyethyleneimines have
a molecular weight of less than about 800, more preferably from about 200 to about
400.
[0017] The cationic charge and the solubility of the polymeric amine allow the deposition
of the polymer onto cotton fabric. The affinity the polymer has for fabric increases
with lower pH, or higher molecular weight. Thus, a balance of these properties (solubility,
solution pH, and polymer molecular weight) controls the efficiency of the chlorine
scavenger on fabric and in solution. The optimal composition will allow a balance
of polymer on fabric (for carryover from wash to rinse) and in solution (for an efficiency
rate of reaction with chlorine).
[0018] Other chlorine scavengers herein are anions selected from the group consisting of
reducing materials like sulfite, bisulfite, thiosulfite, thiosulfate, iodide, nitrite,
etc. and antioxidants like carbamate, ascorbate, etc. and mixtures thereof. Conventional
non-chlorine scavenging anions like sulfate, bisulfate, carbonate, bicarbonate, nitrate,
chloride, borate, phosphate, condensed phosphate, acetate, benzoate, citrate, formate,
lactate, salicylate, etc. and mixtures thereof can be used with ammonium cations.
[0019] Other chlorine scavengers useful herein include ammonium sulfate (preferred), and
primary and secondary amines of low volatility such as ethanolamines, amino acids
and their salts, polyamino acids and their salts, fatty amines, glucoseamine and other
aminated sugars. Specific examples include tris(hydroxymethyl) aminomethane, monoethanol
amine, diethanol amine, sarcosine, glycine, iminodiacetic acid, lysine, ethylenediamine
diacetic acid, 2,2,6,6-tetramethyl piperinol, and 2,2,6,6-tetramethyl piperinone.
[0020] Other chlorine scavengers include phenol, phenol sulfonate, 2,2-biphenol, tiron,
and t-butyl hydroquinone. Preferred are meta-polyphenols such as resorcinol, resorcinol
monoacetate, 2,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, and 2,4-dihydroxyacetophenone.
[0021] Peroxide bleach sources, e.g. perborate, percarbonate and other persalts, can also
be used in minor amounts (less than 3% by weight, preferably less than about 2%) as
a chlorine scavenger herein. However, peroxides are not efficient chlorine scavengers
because they cannot be used at high enough levels to carry over to the rinse water
without risk of bleach damage to colors.
[0022] Detergent compositions comprising the chlorine scavenger and the detergent component
can be provided having various ratios and proportions of these two materials. Of course,
the amount of the chlorine scavenger can be varied, depending upon the level of residual
chlorine expected by the formulator. Moreover, the amount of detergent component can
be varied to provide either heavy-duty or light-duty products, as desired. This invention
relates primarily to detergent compositions that contain essentially no additional
ingredients which are chlorine scavengers. For example, the other materials present
should not provide any substantial additional amounts of ammonium cations in the wash
solution.
Detergent Additives
[0023] The amount of the detergent surfactant component can, as noted hereinabove, vary
over a wide range which depends on the desires of the user. In general, the compositions
contain from about 5% to about 50%, preferably from about 10% to about 30% by weight,
of detergent surfactant, which preferably is an anionic surfactant.
[0024] The detergent compositions of the instant invention can contain all manner of organic,
water-soluble detergent surfactant compounds. A typical listing of the classes and
species of detergent compounds useful herein appear in U.S. Patent 3,664,961, incorporated
herein by reference. The following list of detergent compounds and mixtures which
can be used in the instant compositions is representative of such materials, but is
not intended to be limiting.
[0025] Water-soluble salts of the higher fatty acids, i.e., "soaps", are useful as the detergent
component of the composition herein. This class of detergents includes ordinary alkali
metal soaps such as the sodium, potassium, salts of higher fatty acids containing
from about 8 to about 24 carbon atoms and preferably from about 10 to about 20 carbon
atoms. Soaps can be made by direct saponification of fats and oils or by the neutralization
of free fatty acids. Particularly useful are the sodium and potassium salts of the
mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium or potassium
tallow and coconut soap.
[0026] Another class of detergents includes water-soluble salts, particularly the alkali
metal salts of organic sulfuric reaction products having in their molecular structure
an alkyl group containing from about 8 to about 22 carbon atoms and a sulfonic acid
or sulfuric acid ester group. (Included in the term "alkyl" is the alkyl portion of
acyl groups.) Examples of this group of synthetic detergents which form a part of
the detergent compositions of the present invention are the sodium and potassium alkyl
sulfates, especially those obtained by sulfating the higher alcohols (C₈-C₁₈ carbon
atoms) produced by reducing the glycerides of tallow or coconut oil; and sodium and
potassium alkylbenzene sulfonates, in which the alkyl group contains from about 9
to about 15 carbon atoms, in straight chain or branched chain configuration, e.g.
those of the type described in United States Patents 2,220,099 and 2,477,383, incorporated
herein by reference. Especially valuable are linear straight chain alkylbenzene sulfonates
in which the average of the alkyl groups is about 12 carbon atoms, abbreviated as
C₁₂ LAS.
[0027] Other anionic detergent surfactant compounds herein include the sodium alkyl glyceryl
ether sulfonates, especially those ethers of higher alcohols derived from tallow and
coconut oil; sodium coconut oil fatty acid monoglyceride sulfonates and sulfates;
and sodium or potassium salts of alkyl phenol ethylene oxide ether sulfate containing
from about 1 to about 10 units of ethylene oxide per molecule and wherein the alkyl
groups contain about 8 to about 13 carbon atoms.
[0028] Water-soluble nonionic synthetic detergent surfactants are also useful as the detergent
component of the instant composition. Such nonionic detergent materials can be broadly
defined as compounds produced by the condensation of ethylene oxide groups (hydrophilic
in nature) with an organic hydrophobic compound, which may be aliphatic or alkyl aromatic
in nature. The length of the polyoxyethylene group which is condensed with any particular
hydrophobic group can be readily adjusted to yield a water-soluble compound having
the desired degree of balance between hydrophilic and hydrophobic elements.
[0029] For example, a well-known class of nonionic synthetic detergents is made available
on the market under the trade name of "Pluronic". These compounds are formed by condensing
ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide
with propylene glycol. Other suitable nonionic synthetic detergents include the polyethylene
oxide condensates of alkyl phenols, e.g., the condensation products of alkyl phenols
having an alkyl group containing from about 6 to about 13 carbon atoms in either a
straight chain or branched chain configuration, with ethylene oxide, the said ethylene
oxide being present in amounts equal to from about 4 to about 15 moles of ethylene
oxide per mole of alkyl phenol.
[0030] The water-soluble condensation products of aliphatic alcohols having from about 8
to about 22 carbon atoms, in either straight chain or branched configuration, with
ethylene oxide, e.g., a coconut alcohol-ethylene oxide condensate having from about
3 to about 30 moles of ethylene oxide per mole of coconut alcohol, the coconut alcohol
fraction having from about 10 to about 14 carbon atoms, are also useful nonionic detergents
herein.
[0031] Semi-polar nonionic detergent surfactants include water-soluble amine oxides containing
one alkyl moiety of from about 10 to 20 carbon atoms and 2 moieties selected from
the group consisting of alkyl groups and hydroxyalkyl groups containing from 1 to
about 3 carbon atoms; water-soluble phosphine oxide detergents containing one alkyl
moiety of from about 10 to 20 carbon atoms and 2 moieties selected from the group
consisting of alkyl groups and hydroxyalkyl groups containing from 1 to about 3 carbon
atoms; and water-soluble sulfoxide detergents containing one alkyl or hydroxyalkyl
moiety of from about 10 to about 20 carbon atoms and a moiety selected from the group
consisting of alkyl and hydroxyalkyl moieties of from 1 to about 3 carbon atoms.
[0032] Ampholytic detergent surfactants include derivatives of aliphatic or aliphatic derivatives
of heterocyclic secondary and tertiary amines in which the aliphatic moiety can be
straight chain or branched and wherein one of the aliphatic substituents contains
from about 8 to about 18 carbon atoms and at least one aliphatic substituent contains
an anionic water-solubilizing group.
[0033] Zwitterionic detergent surfactants include derivatives of aliphatic quaternary ammonium,
phosphonium and sulfonium compounds in which the aliphatic moieties can be straight
chain or branched, and wherein one of the aliphatic substituents contains from about
8 to about 18 carbon atoms and one contains an anionic water-solubilizing group. The
quaternary compounds, themselves, e.g. cetyltrimethyl ammonium bromide, can also be
used herein.
[0034] Other useful detergent surfactant compounds herein include the water-soluble salts
of esters of alpha-sulfonated fatty acids containing from about 6 to about 20 carbon
atoms in the fatty acid group and from 1 to about 10 carbon atoms in the ester group;
water-soluble salts of 2-acyloxy-alkane-1-sulfonic acids containing from about 2 to
about 9 carbon atoms in the acyl group and from about 9 to about 20 carbon atoms in
the alkane moiety; alkyl ether sulfates containing from about 10 to about 20 carbon
atoms in the alkyl group and from about 1 to about 12 moles of ethylene oxide; water-soluble
salts of olefin sulfonates containing from about 12 to 20 carbon atoms; and beta-alkyloxy
alkane sulfonates containing from about 1 to 3 carbon atoms in the alkyl group and
from about 8 to 20 carbon atoms in the alkane moiety.
[0035] Preferred water-soluble organic detergent compounds herein include linear alkylbenzene
sulfonates containing from about 11 to about 13 carbon atoms in the alkyl group; C₁₀₋₁₈
alkyl sulfates; the C₁₀₋₁₆ alkyl glyceryl sulfonates; C₁₀₋₁₈ alkyl ether sulfates,
especially wherein the alkyl moiety contains from about 14 to 18 carbon atoms and
wherein the average degree of ethoxylation between 1 and 6; C₁₀₋₁₈ alkyl dimethyl
amine oxides, especially wherein the alkyl group contains from about 11 to 16 carbon
atoms; alkyldimethyl ammonio propane sulfonates and alkyldimethyl ammonio hydroxy
propane sulfonates wherein the alkyl group in both types contains from 14 to 18 carbon
atoms; soaps, as hereinabove defined; and the condensation product of C₁₀₋₁₈ fatty
alcohols with from about 3 to about 15 moles of ethylene oxides.
[0036] Specific preferred detergents for use herein include: sodium linear C₁₀₋₁₃ alkylbenzene
sulfonates; sodium C₁₂₋₁₈ alkyl sulfates; sodium salts of sulfated condensation product
of C₁₂₋₁₈ alcohols with from about 1 to about 3 moles of ethylene oxide; the condensation
product of a C₁₀₋₁₈ fatty alcohols with from about 4 to about 10 moles of ethylene
oxide; and the water-soluble sodium and potassium salts of higher fatty acids containing
from about 10 to about 18 carbon atoms.
[0037] It is to be recognized that any of the foregoing detergents can be used separately
herein, or as mixtures. Examples of preferred detergent mixtures herein are as follows.
[0038] An especially preferred alkyl ether sulfate detergent component of the instant compositions
is a mixture of alkyl ether sulfates, said mixture having an average (arithmetic mean)
carbon chain length within the range of from about 12 to 16 carbon atoms, preferably
from about 14 to 15 carbon atoms, and an average (arithmetic mean) degree of ethoxylation
of from about 1 to 4 moles of ethylene oxide, preferably from about 1 to 3 moles of
ethylene oxide.
[0039] The detergent compositions of the present invention can contain, in addition to the
detergent surfactant, water-soluble or water-insoluble builders such as those commonly
taught for use in detergent compositions. Such auxiliary builders can be employed
to sequester hardness ions and to help adjust the pH of the laundering liquor. Such
builders can be employed in concentrations of from about 5% to about 95% by weight,
preferably from about 10% to about 50% by weight, of the detergent compositions herein
to provide their builder and pH-controlling functions. The builders herein include
any of the conventional inorganic and organic water-soluble builder salts.
[0040] Such builders can be, for example, water-soluble salts of phosphates including tripolyphosphates,
pyrophosphates, orthophosphates, higher polyphosphates, carbonates, silicates, and
organic polycarboxylates. Specific preferred examples of inorganic phosphate builders
include sodium and potassium tripolyphosphates and pyrophosphates.
[0041] Nonphosphorus-containing materials can also be selected for use herein as builders.
[0042] Specific examples of nonphosphorus, inorganic detergent builder ingredients include
water-soluble inorganic carbonate, bicarbonate, and silicate salts. The alkali metal,
e.g., sodium and potassium, carbonates, bicarbonates, and silicates are particularly
useful herein.
[0043] Aluminosilicate ion exchange materials useful in the practice of this invention are
commercially available. The aluminosilicates useful in this invention can be crystalline
or amorphous in structure and can be naturally-occurring aluminosilicates or synthetically
derived. A method for producing aluminosilicate ion exchange materials is discussed
in U.S. Pat. No. 3,985,669, Krummel et al, issued Oct. 12, 1976, incorporated herein
by reference. Preferred synthetic crystalline aluminosilicate ion exchange materials
useful herein are available under the designations Zeolite A, Zeolite B, and Zeolite
X. In an especially preferred embodiment, the crystalline aluminosilicate ion exchange
material in Zeolite A and has the formula
Na₁₂[AlO₂)₁₂.(SiO₂)₁₂].xH₂O
wherein x is from about 20 to about 30, especially about 27.
[0044] Water-soluble, organic builders are also useful herein. For example, the alkali metal,
polycarboxylates are useful in the present compositions. Specific examples of the
polycarboxylate builder salts include sodium and potassium, salts of ethylenediaminetetraacetic
acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzene polycarboxylic
acid, polyacrylic acid, polymaleic acid, and citric acid.
[0045] Other desirable polycarboxylate builders are the builders set forth in U.S. Patent
3,308,067, Diehl, incorporated herein by reference. Examples of such materials include
the water-soluble salts of homo- and co-polymers of aliphatic carboxylic acids such
as maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, citraconic
acid, and methylenemalonic acid.
[0046] Other suitable polymeric polycarboxylates are the polyacetal carboxylates described
in U.S. Pat. No. 4,144,226, issued Mar. 13, 1979 to Crutchfield et al, and U.S. Pat.
No. 4,246,495, issued Mar. 27, 1979 to Crutchfield et al, both incorporated herein
by reference. These polyacetal carboxylates can be prepared by bringing together under
polymerization conditions an ester of glyoxylic acid and a polymerization initiator.
The resulting polyacetal carboxylate ester is then attached to chemically stable end
groups to stabilize the polyacetal carboxylate against rapid depolymerization in alkaline
solution, converted to the corresponding salt, and added to a surfactant.
[0047] Preferred builders herein are polycarboxylic acids, especially citric acid, which
preferably are used at a level of from about 5% to about 10% by weight, and sodium
acid pyrophosphate, which preferably is used at a level of from about 5% to about
15% by weight. Such materials function as both builder and acid source to adjust pH
to the desired range.
Detergent Adjuvants
[0048] The detergent compositions herein can contain all manner of additional materials,
detergent adjuvants, commonly found in laundering and cleaning compositions. For example,
the compositions can contain thickeners and soil-suspending agents such as carboxymethylcellulose
and the like. Various enzymes, enzyme stabilizers, suds suppressors, perfumes, optical
bleaches, fillers, anticaking agents, fabric softeners and the like can be present
in the compositions to provide the usual benefits occasioned by the use of such materials
in detergent compositions.
[0049] The compositions herein are essentially free of oxygen bleaching agents, since if
they are present, there is no need for the chlorine scavenger. Similarly, there should
be no chlorine bleaching agent present since the chlorine scavenger would not be effective
against a large amount of available chlorine.
[0050] A finished detergent composition of this invention can contain minor amounts of materials
which make the product more attractive. The following are mentioned by way of example:
a tarnish inhibitor such as benzotriazole or ethylene thiourea can be added in amounts
up to 2% by weight; fluorescers, perfumes and dyes, while not essential, can be added
in small amounts. An alkaline material such as sodium or potassium carbonate or hydroxide
can be added in minor amounts as supplementary pH adjusters. There may also be mentioned,
as suitable additives: bacteriostats, bactericides, corrosion inhibitors such as soluble
alkali silicates (preferably sodium silicates having an SiO₂/Na₂O ratio of from 1:1
to 2.8:1), and textile softening agents.
[0051] Particularly preferred compositions herein are granular laundry detergents comprising
by weight:
(a) from about 15% to about 25% of a mixture of a C₁₁₋C₁₃ (preferably C₁₂₋C₁₃) alkylbenzene
sulfonate surfactant and a C₁₂₋C₁₆ (preferably C₁₄-C₁₅) alkyl sulfate surfactant in
a weight ratio of sulfonate surfactant to sulfate surfactant of from about 4:1 to
about 1:1;
(b) from about 1% to about 3% of an alkali metal (preferably sodium) silicate having
a molar ratio of SiO₂ to alkali metal oxide of from about 1.0 to about 2.4;
(c) from about 20% to about 30% of a finely divided aluminosilicate ion exchange material
selected from the group consisting of:
(i) crystalline aluminosilicate material of the formula:
Naz[(AlO₂)z.(SiO₂)y].xH₂O
wherein z and y are at least 6, the molar ratio of z to y is from 1.0 to 0.5 and x
is from 10 to 264, said material having a particle size diameter of from about 0.1
micron to about 10 microns, a calcium ion exchange capacity of at least about 200
mg CaCO₃ eq./g and a calcium ion exchange rate of at least about 2 grains Ca⁺⁺/gallon/minute/gram/gallon;
(ii) amorphous hydrated aluminosilicate material of the empirical formula:
Mz(zAlO₂.ySiO₂)
wherein M is sodium, potassium, ammonium, or substituted ammonium, z is from about
0.5 to about 2 and y is 1, said material having a magnesium ion exchange ion exchange
capacity of at least about 50 milligram equivalents of CaCO₃ hardness per gram of
anhydrous aluminosilicate and a Mg⁺⁺ exchange rate of at least about 1 grain/gallon/minute/gram/gallon;
and
(iii) mixtures thereof;
(d) from about 4% to about 10% of citric acid;
(e) from about 5% to about 20% of an alkali metal (preferably sodium) carbonate;
said composition having a pH of from about 7 to about 9.3 at a concentration of 1%
by weight in water at 20°C, and said composition having a density of from about 500
to about 600 grams per liter.
[0052] Preferred alumionosilicate ion exchange material is of the formula Na₁₂[(A1O₂)₁₂(SiO₂)12].xH₂O,
wherein x is from about 20 to about 30.
[0053] The above granular detergent compositions provide good cleaning performance due to
the relatively high levels of anionic surfactants and aluminosilicate, citric acid,
and carbonate builders. Despite having a density of from about 500 to about 600 grams
per liter, the compositions have good physical properties, i.e., they are free-flowing
and are readily soluble in the laundering solution. The citric acid and carbonate
levels are selected to obtain the required pH range and provide additional builder
function to the aluminosilicate material.
[0054] All percentages, parts and ratios herein are by weight unless otherwise specified.
[0055] The following examples illustrate the compositions herein.
EXAMPLES
[0056] Granular detergent compositions of the present invention comprise the following ingredients:

[0057] Aqueous crutcher mixes of the detergent compositions are prepared and spray-dried,
except for the citric acid, sodium acid pyrophosphate, enzyme, perfume, and ammonium
sulfate or perborate, which are admixed, so that they contain the above ingredients
at the levels shown.
[0058] Fabrics laundered using the above compositions retain their color over time better
than similar compositions not containing the chlorine scavenger or formulated to provide
a higher wash pH.