Enzyme Detergent Composition Containing Coagglomerated Perborate Bleaching Agent

Abstract

An enzyme granular detergent composition having improved enzyme stability which comprises at least one water soluble organic synthetic detergent, at least one water soluble detergency builder, an enzyme, and from about 0.005 to 50 percent by weight of a coagglomerated sodium perborate bleaching agent consisting essentially of sodium perborate, a water-soluble polymeric organic agglomerating agent which forms a tacky solution with water at 72 .degree. F., and a water-soluble granular coagglomerant.

Description

FIELD OF THE INVENTION

This invention relates to a process of incorporating a sodium perborate granular bleaching agent into an enzyme containing granular laundry detergent composition in a manner which effectively overcomes the problem of product segregation while maintaining the perborate in a stable form and simultaneously provides a more improved stable enzyme product. The invention also relates to the improved products formed by this process.

BACKGROUND OF THE INVENTION

Sodium perborate is a well-known granular oxidizing bleaching agent. It is widely used in combination with granular detergents and builders to aid in a laundry cleaning process, e.g., an ordinary home laundry situation. It is possible to prepare granular mechanical mixtures of these ingredients in preparing such products. However, a major problem in such granular mixtures is that the commercially available, sodium perborate granules are much smaller than ordinary spray-dried detergent granules, and as a result, they tend to segregate to the bottom of a carton or package. This results in uneven dispensing and usage of the sodium perborate bleaching agent when a granular detergent product is poured from a container.

Sodium perborate in its ordinary commercially available form is a fine granular or powder material. Particle size analysis indicates that typically about 99 percent of the sodium perborate granules pass through a 28 Tyler mesh, and about 75 percent pass through a 35 Tyler mesh. Particle sizes ordinarily range from about 0.0234 inch to smaller than 0.003 inch.

By comparison, ordinary spray-dried detergent composition granules are considerably larger. A major portion, e.g., more than about 75 percent is retained on a 35 Tyler mesh. Less than about 25 percent of the granules are in the smaller ordinary sodium perborate particle size range.

Because of these significant particle size differences, the smaller sodium perborate granules tend to separate towards the bottom of a granular mechanical mixture of spray-dried detergent granules and fine sodium perborate powdery granules. This as been a problem in the detergent manufacturing industry for a long time.

One method of incorporating the fine sodium perborate granules described above into a granular spray-dried detergent composition includes a step of fusing the fine sodium perborate granules onto larger spray-dried granules at the base of a spray tower while the granules are still hot from spray-drying, e.g., ranging from about 160.degree.-220.degree. F. This is accomplished by mixing perborate granules with hot spray-dried granules and agitating the mixture. The heat causes the perborate granules to melt on the surface of the larger spray-dried granules and become fused to them upon cooling. While this process is effective in securing attachment to the larger detergent granules and thus achieving fairly uniform distribution of a sodium perborate bleaching agent in a detergent composition, this embodiment has certain considerable disadvantages. For instance, the fusion temperature can result in the partial degradation of the sodium perborate and the premature release and partial loss of available oxygen. In addition, the fused form of the sodium perborate granules can result in decreased stability of the fused sodium perborate bleaching agent due to the continuing release of oxygen. Moreover, since the fused sodium perborate is primarily present on the surface of the larger spray-dried detergent granules it is thereby exposed and can undesirably come into contact with and react with other ingredients in the composition.

It is an object of this invention to provide a process which not only provides a non-segregating coagglomerated perborate-containing granular composition, but also a coagglomerated sodium perborate composition which retains the maximum amount of available oxygen content and which is protected from the other possibly degrading ingredients which comprise an ordinary granular built detergent composition.

One of the unexpected discoveries of the present invention is that the coagglomerated sodium perborate product prepared in the manner described herein is less harmful in its attack on enzymes when both are present in a granular detergent composition. This is all the more surprising because the perborate is in a highly concentrated form in the agglomerated physical form and it might be expected that this would increase the danger to the enzyme component.

SUMMARY OF THE INVENTION

This invention provides a coagglomerated sodium perborate composition composed of sodium perborate, a water-soluble polymeric agglomerating agent, and a granular coagglomerant which can be any water-soluble granular composition which is compatible with the sodium perborate and ordinary ingredients of a granular detergent composition and which does not interfere with the primary objective of formulating an effective laundry detergent composition.

The process for producing the coagglomerated sodium perborate composition of this invention comprises the steps of agitating a dry mixture of sodium perborate granules and coagglomerant granules, and spraying said dry granular mixture with a slurry of water and a water-soluble polymeric agglomerating agent which forms a tacky solution with water at about 72.degree. F., the temperature of said slurry ranging from 50.degree. F. to 180.degree. F.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, a process is provided for preparing a coagglomerated sodium perborate composition which comprises the steps of (1) blending a dry mixture of 1 to 99 percent by weight sodium perborate granules and 1 - 99 percent by weight of a water-soluble granular coagglomerant selected from the group consisting of sulfates, thiosulfates, carboxymethyl cellulose, starch, an organic synthetic detergent selected from anionic, nonionic, ampholytic, or zwitterionic detergents, a builder salt selected from organic or inorganic sequestering builder salts, or a spray-dried granular detergent composition consisting essentially of at least one water-soluble organic synthetic detergent and at least one water-soluble builder salt selected from organic or inorganic sequestering builder salts, the proportion of said detergent to said builder being in the range of 5:1 to 1:20, and (2) spraying said dry mixture with an aqueous slurry of a water-soluble polymeric agglomerating agent which forms a tacky aqueous solution at about 72.degree. F., the concentration of said polymeric agglomerating agent in said aqueous slurry being from 1 to 40 percent by weight, said slurry having a temperature in the range of 50.degree. F. to 180.degree. F. While the preceding ranges for conditions are permissible for practicing this invention, best results are achieved when the dry mixture is comprised of 50 to 95 percent sodium perborate granules and 5 to 50 percent of coagglomerant granules, the concentration of the polymeric agglomerating agent in the slurry is 5 to 25 percent and the temperature of the slurry is 70.degree. to 160.degree. F.

There are no known limitations on the sodium perborate granular bleaching agent which can be used in practicing this invention.

Examples of permissible water-soluble coagglomerants are sodium sulfate, sodium thiosulfate, sodium carboxymethyl cellulose, and starch. The following synthetic detergents also are useful.

A. ANIONIC SOAP AND NON-SOAP SYNTHETIC DETERGENTS

This class of detergents includes ordinary alkali metal soaps such as the sodium, potassium, ammonium and alkylolammonium salts of higher fatty acids containing from about eight to about 24 carbon atoms and preferably from about 10 to about 20 carbon atoms. Suitable fatty acids can be obtained from natural sources such as, for instance, from plant or animal esters (e.g., palm oil, coconut oil, babassu oil, soybean oil, caster oil, tallow, whale and fish oils, grease, lard, and mixtures thereof). The fatty acids also can be synthetically prepared (e.g., by the oxidation of petroleum, or by hydrogenation of carbon monoxide by the Fischer-Tropsch process). Resin acids are suitable such as rosin and those resin acids in tall oil. Napthenic acids are also suitable. Sodium and potassium soaps can be made by direct saponification of the fats and oils or by the neutralization of the free fatty acids which are prepared in a separate manufacturing process. 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.

This class of detergents also includes water-soluble salts, particularly the alkali metal salts of organic sulfuric reaction products having in their molecular structure an alkyl radical containing from about eight to about 22 carbon atoms and a sulfonic acid or sulfuric acid ester radical. (Included in the term alkyl is the alkyl portion of higher acyl radicals.) Examples of this group of synthetic detergents which form a part of the preferred built detergent compositions of the present invention are the sodium or potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C.sub.8 - C.sub.18 carbon atoms) produced by reducing the glycerides of tallow or coconut oil; sodium or potassium alkyl benzene sulfonates, in which the alkyl group contains from about nine to about 15 carbon atoms, in straight chain or branched chain configuration, e.g., those of the type described in U.S. Pats. Nos. 2,220,099 and 2,477,383 (especially valuable are linear straight chain alkyl benzene sulfonates in which the average of the alkyl groups is about 13 carbon atoms abbreviated hereinafter as C.sub.13 LAS); 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; 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 oil alcohols) and about 1 to 6 moles of ethylene oxide; sodium or potassium salts of alkyl phenol ethylene oxide ether sulfate with about 1 to about 10 units of ethylene oxide per molecule and in which the alkyl radicals contain about eight to about 12 carbon atoms.

Additional examples of anionic non-soap synthetic detergents which come within the terms of the present invention are the reaction product of fatty acids esterified with isethionic acid and neutralized with sodium hydroxide where, for example, the fatty acids are derived from coconut oil; sodium or potassium salts of fatty acid amide of methyl tauride in which the fatty acids, for example, are derived from coconut oil. Other anionic synthetic detergents of this variety are set forth in U.S. Pat. Nos. 2,486,921; 2,486,922; and 2,396,278.

Still other anionic synthetic detergents include the class designated as succinamates. This class includes such surface active agents as disodium N-octadecylsulfo succinamate; tetrasodium N-(1,2-dicarboxyethyl)-N-octadecyl-sulfo-succinamate; diamyl ester of sodium sulfosuccinic acid; dihexyl ester of sodium sulfosuccinic acid; dioctyl ester of sodium sulfosuccinic acid.

Anionic phosphate surfactants are also useful in the present invention. These are surface active materials having substantial detergent capability in which the anionic solubilizing group connecting hydrophobic moieties is an oxy acid of phosphorus. The more common solubilizing groups, of course, are --SO.sub.4 H, --SO.sub.3 H, and --CO.sub.2 H. Alkyl phosphate esters such as (R--O).sub.2 PO.sub.2 H and ROPO.sub.3 H.sub.2 in which R represents an alkyl chain containing from about eight to about 20 carbon atoms are useful.

These esters can be modified by including in the molecule from one to about 40 alkylene oxide units, e.g., ethylene oxide units. Formulae for these modified phosphate anionic detergents are ##SPC1##

in which R represents an alkyl group containing from about eight to 20 carbon atoms, or an alkylphenyl group in which the alkyl group contains from about eight to 20 carbon atoms, and M represents a soluble cation such as hydrogen, sodium, potassium, ammonium or substituted ammonium; and in which n is an integer from 1 to about 40.

A specific anionic detergent which has also been found excellent for use in the present invention is described more fully in the U.S. Pat. No. 3,332,880 of Phillip F. Pflaumer and Adriaan Kessler, issued July 25, 1967, titled Detergent Composition. This detergent comprises by weight from about 30 percent to about 70 percent of Component A, from about 20 percent to about 70 percent of Component B, and from about 2 percent to about 15 percent of Component C, wherein:

a. said Component A is a mixture of double-bond positional isomers of water soluble salts of alkene-1-sulfonic acids containing from about 10 to about 24 carbon atoms, said mixture of positional isomers including about 10 percent to about 25 percent of an alpha-beta unsaturated isomer, about 30 percent to about 70 percent of a beta-gamma unsaturated isomer, about 5 percent to about 25 percent of a gamma-delta unsaturated isomer, and about 5 percent to about 10 percent of a delta-epsilon unsaturated isomer;

b. said Component B is a mixture of water soluble salts of bifunctionally-substituted sulfur-containing saturated aliphatic compounds containing from about 10 to about 24 carbon atoms, the functional units being hydroxy and sulfonate radicals with the sulfonate radical always being on the terminal carbon and the hydroxyl radical being attached to a carbon atom at least two carbon atoms removed from the terminal carbon atom, at least 90 percent of the hydroxy radical substitutions being in the 3, 4, and 5 positions; and

c. said Component C is a mixture comprising from about 30 to 95 percent water-soluble salts of alkene disulfonates containing from about 10 to about 24 carbon atoms, and from about 5 percent to about 70 percent water-soluble salts of hydroxy disulfonates containing from about 10 to about 24 carbon atoms, said alkene disulfonates containing a sulfonate group attached to a terminal carbon atom and a second sulfonate group attached to an internal carbon atom not more than about six carbon atoms removed from said terminal carbon atom, the alkene double bond being distributed between the terminal carbon atom and about the seventh carbon atom, said hydroxy disulfonates being saturated aliphatic compounds having a sulfonate radical attached to a terminal carbon, a second sulfonate group attached to an internal carbon atom not more than about six carbon atoms removed from said terminal carbon atom, and a hydroxy group attached to a carbon atom which is not more than about four carbon atoms removed from the site of attachment of said second sulfonate group.

B. NONIONIC SYNTHETIC DETERGENTS

Nonionic synthetic detergents may be broadly defined as compounds produced by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound, which may be aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene radical 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.

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. The hydrophobic portion of the molecule which, of course, exhibits water insolubility, has a molecular weight of from about 1,500 to 1,800. The addition of polyoxyethylene radicals to this hydrophobic portion tends to increase the water solubility of the molecule as a whole and the liquid character of the product is retained up to the point where polyoxyethylene content is about 50 percent of the total weight of the condensation product.

Other suitable nonionic synthetic detergents include:

1. The polyethylene oxide condensates of alkyl phenols, e.g., the condensation products of alkyl phenols having an alkyl group containing from about six to 12 carbon atoms in either a straight chain or branched chain configuration, with ethylene oxide, the said ethylene oxide being present in amounts equal to 5 to 25 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds may be derived from polymerized propylene, diisobutylene, octene, or nonene, for example.

2. Those derived from the condensation of ethylene oxide with the product resulting from the reaction of propylene oxide and ethylene diamine. For example, compounds containing from about 40 percent to about 80 percent polyoxyethylene by weight and having a molecular weight of from about 5,000 to about 11,000 resulting from the reaction of ethylene oxide groups with a hydrophobic base constituted of the reaction product of ethylene diamine an excess propylene oxide, said base having a molecular weight of the order of 2,500 to 3,000, are satisfactory.

3. The condensation product of aliphatic alcohols having from eight to 22 carbon atoms, in either straight chain or branched chain configuration, with ethylene oxide, e.g., a coconut alcohol-ethylene oxide condensate having from 5 to 30 moles of ethylene oxide per mole of coconut alcohol, the coconut alcohol fraction having from 10 to 14 carbon atoms.

4. Nonionic detergents include nonyl phenol condensed with either about 10 or about 30 moles of ethylene oxide per mole of phenol and the condensation products of coconut alcohol with an average of either about 5.5 or about 15 moles of ethylene oxide per mole of alcohol and the condensation product of about 15 moles of ethylene oxide with one mole of tridecanol.

Other examples include dodecylphenol condensed with 12 moles of ethylene oxide per mole of phenol; dinonylphenol condensed with 15 moles of ethylene oxide per mole of phenol; dodecyl mercaptan condensed with 10 moles of ethylene oxide per mole of mercaptan; bis-(N-2-hydroxyethyl) lauramide; nonyl phenol condensed with 20 moles of ethylene oxide per mole of nonyl phenol; myristyl alcohol condensed with 10 moles of ethylene oxide per mole of myristyl alcohol; lauramide condensed with 15 moles of ethylene oxide per mole of lauramide; and di-iso-octylphenol condensed with 15 moles of ethylene oxide.

5. A detergent having a formula R.sup.1 R.sup.2 R.sup.3 N.fwdarw.O (amine oxide detergent) wherein R.sup.1 is an alkyl group containing from about 10 to about 28 carbon atoms, from zero to about two hydroxy groups and from zero to about five ether linkages, there being at least one moiety of R.sup.1 which is an alkyl group containing from about 10 to about 18 carbon atoms and zero ether linkages, and each R.sup.2 and R.sup.3 are selected from the group consisting of alkyl radicals and hydroxyalkyl radicals containing from one to about three carbon atoms;

Specific examples of amine oxide detergents include:

dimethyldodecylamine oxide

dimethyltetradecylamine oxide

ethylmethyltetradecylamiine oxide

cetyldimethylamine oxide

dimethylstearylamine oxide

cetylethylpropylamine oxide

diethyldodecylamine oxide

diethyltetradecylamine oxide

dipropyldodecylamine oxide

bis-(2-hydroxyethyl)dodecylamine oxide

bis-(2-hydroxyethyl)-3-dodecoxy-1-hydroxypropyl amine oxide

(2-hydroxypropyl)methyltetradecylamine oxide

dimethyloleyamine oxide

dimethyl-(2-hydroxydodecyl)amine oxide

and the corresponding decyl, hexadecyl and octadecyl homologs of the above compounds.

6. A detergent having the formula R.sup.1 R.sup.2 R.sup.3 P.fwdarw.O (phosphine oxide detergent) wherein R.sup.1 is an alkyl group containing from about 10 to about 28 carbon atoms, from zero to about two hydroxy groups and from zero to about five ether linkages, there being at least one moiety of R.sup.1 which is an alkyl group containing from about 10 to about 18 carbon atoms and zero ether linkages, and each of R.sup.2 and R.sup.3 are selected from the group consisting of alkyl radicals and hydroxyalkyl radicals containing from one to about three carbon atoms.

Specific examples of the phosphine oxide detergents include:

dimethyldodecylphosphine oxide

dimethyltetradecylphosphine oxide

ethylmethyltetradecylphosphine oxide

cetyldimethylphosphine oxide

dimethylstearylphosphine oxide

cetylethylpropylphosphine oxide

diethyldodecylphosphine oxide

diethyltetradecylphosphine oxide

dipropyldodecylphosphine oxide

bis-(hydroxymethyl)dodecylphosphine oxide

bis-(2-hydroxyethyl)dodecylphosphine oxide

(2-hydroxypropyl)methyltetradecylphosphine oxide

dimethyloleylphosphine oxide, and

dimethyl-(2-hydroxydodecyl)phosphine oxide

and the corresponding decyl, hexadecyl, and octadecyl homologs of the above compounds.

7. A detergent having the formula

(sulfoxide detergent) where R.sup.1 is an alkyl radical containing from about 10 to about 28 carbon atoms, from zero to about five ether linkages and from zero to about two hydroxyl substituents at least one moiety of R.sup.1 being an alkyl radical containing zero ether linkages and containing from about 10 to about 18 carbon atoms, and wherein R.sup.2 is an alkyl radical containing from one to three carbon atoms and from one to two hydroxyl groups.

octadecyl methyl sulfoxide

dodecyl methyl sulfoxide

tetradecyl methyl sulfoxide

3-hydroxytridecyl methyl sulfoxide

3-methoxytridecyl methyl sulfoxide

3-hydroxy-4-dodecoxybutyl methyl sulfoxide

octadecyl 2-hydroxyethyl sulfoxide

dodecylethyl sulfoxide

C. AMPHOLYTIC SYNTHETIC DETERGENTS

Ampholytic synthetic detergents can be broadly described as derivatives of aliphatic or aliphatic derivatives of heterocyclic secondary and tertiary amines, in which the aliphatic radical may be straight chain or branched and wherein one of the aliphatic substituents contains from about eight to 18 carbon atoms and at least one contains an anionic water-solubilizing group, e.g., carboxy, sulfo, sulfato, phosphato, or phosphono. Examples of compounds falling within this definition are ##SPC2## ##SPC3## ##SPC4##

D. ZWITTERIONIC SYNTHETIC DETERGENTS

Zwitterionic synthetic detergents can be broadly described as derivatives of aliphatic quaternary ammonium and phosphonium or tertiary sulfonium compounds, in which the cationic atom may be part of a heterocyclic ring, and in which the aliphatic radical may be straight chain or branched, and wherein one of the aliphatic substituents contains from about three to 18 carbon atoms, and at least one aliphatic substituent contains an anionic water-solubilizing group, e.g., carboxy, sulfo, sulfato, phosphato, or phosphono. Examples of compounds falling within this definition are ##SPC5## ##SPC6## ##SPC7##

Some of these detergents are described in the following U.S. Pat. Nos. 2,129,264; 2,178,353; 2,774,786; 2,813,898; and 2,828,332.

Water-soluble inorganic in builder salts which can be used i this invention alone or in admixture are alkali metal carbonates, borates, phosphates, polyphosphates, bicarbonates and silicates. Ammonium or substituted ammonium, e.g., triethanol ammonium, salts of these materials can also be used. Specific examples of suitable salts are sodium tripolyphosphate, sodium carbonate, sodium tetraborate, sodium and potassium pyrophosphate, sodium and ammonium bicarbonate, potassium tripolyphosphate, sodium hexametaphosphate, sodium sesquicarbonate, sodium orthophosphate and potassium bicarbonate. The preferred inorganic alkaline builders according to this invention are alkali metal tripolyphosphates for built granular compositions.

Examples of suitable organic alkaline sequestrant builder salts used in this invention alone or in admixture are alkali metal, ammonium or substituted ammonium, aminocarboxylates, e.g., sodium and potassium ethylenediaminetetraacetate, sodium and potassium N-(2-hydroxyethyl)-ethylenediaminetriacetates, sodium and potassium nitrilotriacetates and sodium, potassium and triethanolammonium N-(2-hydroxyethyl)-nitrilodiacetates. Mixed salts of these polycarboxylates are also suitable. The alkali metal salts of phytic acid, e.g., sodium phytate are also suitable as organic alkaline sequestrant builder salts (see U.S. Pat. No. 2,739,942). Sodium ethane-1-hydroxy-1-diphosphonate, and sodium citrate can also be used as builders either alone or in mixtures with other builder compounds. Other suitable builders include methylene and ethylene diphosphonates and their derivatives, ethene-1-hydroxy-1,1,2-triphosphonate, sodium itaconate, and sodium polymaleate.

An especially preferred coagglomerant is a spray-dried granular built detergent consisting essentially of a water-soluble synthetic detergent and a builder salt, the proportion by weight of said detergent to said builder being from 5:1 to 1:20. The detergent ingredient and the builder salt can be selected from those mentioned above. The preferred class of detergents is the anionic class and specifically sodium linear alkyl benzene sulfonate, the alkyl having eight to 20 carbon atoms, sodium fatty alcohol sulfates (tallow and coconut), and sodium olefin sulfonates. The preferred builders are sodium tripolyphosphate, sodium nitrilotriacetate, or a mixture of these two builders in a ratio by weight of 4:1 to 1:4.

The polymeric agglomerating agent used in practicing this invention can be selected from a large number of materials. It is contemplated that any polymeric agglomerating agent can be used which when mixed with water at about 72.degree. F. forms a tacky solution. No material has been found unsatisfactory for practicing this invention which satisfies this one criteria. The following materials are examples of useful polymeric agglomerating agents: a linear interpolymer of methyl vinyl ether and maleic anhydride having a specific viscosity of 0.1 - 0.5 as measured on a solution of 1 g. of the copolymer in 100 ml. of MEK at 25.degree. C.; polyacrylic acid; cross-linked, pre-gelatinized amylopectin; amylopectin; poly(ethylene oxide) homopolymer; linear copolymer of ethylene and maleic anhydride; methyl cellulose; starch; gelatin; and polysaccharide gum. The preferred agglomerating agents are the linear interpolymer of methyl vinyl ether and maleic anhydride and the cross-linked pre-gelatinized amylopectin.

Practicing the process for preparing the coagglomerated perborate product is relatively simple. The previously mentioned granular dry mixture is prepared in any convenient manner. An aqueous slurry of the agglomerating agent is prepared and sprayed into the agitated dry mixture. Any suitable spraying device can be used to spray the mixture of water and the agglomerating agent onto the dry mixture of the perborate and coagglomerant. Coagglomeration occurs in an even and uniform manner. Virtually no additional processing step is required. The coagglomerated product dries readily and is available for use almost immediately.

The amount of agglomerating agent applied to the dry granular mixture need only be sufficient to effect the desired degree of agglomeration. This can readily be determined by taking into consideration the ultimate use of the coagglomerated perborate product. On a weight basis the amount of agglomerating agent can range from 0.05 percent to about 4 percent of the combined weight of the perborate, coagglomerant and agglomerating agent; preferably from 0.1 to about 3 percent.

The coagglomerated product provides alternative uses. For instance, if the coagglomerant used is a detergent composition, the coagglomerated product can be used directly as a useful laundering composition. Alternatively the coagglomerated product can be used as an additive to a complete detergent or laundering composition in an amount sufficient to provide the desired level of sodium perborate bleaching agent. A preferred embodiment of this invention is a laundry detergent composition consisting essentially of a spray-dried mixture comprising a water-soluble synthetic detergent and a water-soluble builder salt in a proportion by weight of 5:1 to 1:20, and a coagglomerated sodium perborate granular product consisting essentially of sodium perborate; a water-soluble polymeric agglomerating agent which forms a tacky slurry with water at about 72.degree. F.; and a water-soluble granular coagglomerant which is selected from sodium sulfate, sodium thiosulfate, sodium carboxymethyl cellulose, natural unmodified starch, an organic synthetic detergent, an organic or inorganic sequestering builder salt, and a spray-dried granular composition consisting essentially of an organic synthetic detergent and an organic or inorganic sequestering builder salt, the proportion by weight of said detergent to said builder being from 5:1 to 1:20, the amount of said coagglomerated perborate product being sufficient o provide from 1 percent to 60 percent by weight of the composition, preferably from 5 percent to 50 percent, sodium perborate bleaching agent.

The spray-dried granular detergent composition mentioned the in the examples below has the following composition:

16.8% A 55%-45% mixture by weight of sodium linear tridecyl benzene sulfonate and sodium tallow alkyl sulfate

49.5% Sodium tripolyphosphate

6.0% Sodium silicate

14.0% Sodium sulfate

10.0% Water

3.7% Optical brighteners, benzotriazole, carboxymethyl cellulose and minors

Having described the invention in detail above, the invention is now illustrated by the following examples.

EXAMPLE I

Three hundred pounds of sodium perborate powder, having a particle size distribution ranging from Tyler 35 mesh to smaller than Tyler 100 mesh (0.0165 inches to smaller than 0.0016 inches) with about 75 percent of the total sodium perborate particles smaller than Tyler 35 mesh (0.00165 inch), were added to a baffled drum mixer. To this mixer were added 300 pounds of a spray dried granular detergent composition described above having a particle size distribution ranging from Tyler 10 mesh (0.0661 inches) to smaller than Tyler 100 mesh with about 75 percent of the total granular detergent particles larger than Tyler 35 mesh.

The granular mixture of these two materials was dry mixed by rotating the baffled drum mixer.

As the drum was rotating, a slurry of 75 percent water and 25 percent of an agglomerating agent which was a linear interpolymer of methyl vinyl ether and maleic anhydride having a specific viscosity (nsp) of 0.1 - 0.5 as measured on a solution of 1 gm. of the copolymer in 100 ml. of MEK at 25.degree. C., and comprised of the following repeating unit:

was uniformly sprayed onto the agitating dry mixture. The agglomerating agent was obtained from The General Aniline and Film Corporation and is identified as Gantrez AN-119. (Technical Bulletin 7543-017). The slurry was prepared by mixing 17 pounds of the agglomerating agent with 51 pounds of water at a temperature of 150.degree. F. There is a substantial temperature loss in the slurry between the spray nozzles and the dry granular particles. Upon contact with the particles, the slurry spray has a temperature of about 100.degree. F. The 68 pounds of slurry was uniformly sprayed at a pressure of about 160 pounds per square inch over a time period of about 6 minutes onto the 600 pounds of dry granular mix in the drum mixer.

The resultant agglomerated mixture contained 44.9 percent sodium perborate, 44.9 percent spray-dried granular detergent, 2.5 percent polymeric methyl vinyl ether/maleic anhydride agglomerating agent and 7.7 percent water.

As the slurry of the agglomerating agent was sprayed onto the dry powder mixture coagglomeration began immediately. To determine how fast and how efficient coagglomeration was taking place, uniform samples were removed from the drum during the mixing and spraying operation at specific time intervals (15 seconds, 30 seconds, 1 minute, 2 minutes, etc.). the granular samples were examined for changes in particle size distribution. By observing the rate at which the small particles were disappearing (i.e., how quickly and uniformly large particles were forming from the smaller particles), it was determined that the desired coagglomeration had taken place.

The following data shows the agglomerating effect upon the small particles with short time increments. ##SPC8##

It can be seen from the data in the table that the coagglomeration proceeded smoothly and rapidly. The resulting coagglomerated perborate particles were spherical, substantially dust-free, freely flowing particles requiring no further processing such as cooling and drying. A very significant aspect of this process is that analytical measurements showed no measurable loss in available oxygen content of the perborate agglomerates thereby indicating the processing steps had not degraded the sodium perborate.

This example demonstrates preparing a coagglomerated perborate bleaching granular product having a particle size distribution approximating the particle size distribution of ordinary spray-dried detergent granules with which the perborate bleaching granule can be mixed without concern for substantial segregation of the particles. This advantage provides a detergent composition offering a housewife uniform cleaning and bleaching characteristics.

The following table compares the particle sizes of typical perborate particles, typical spray-dried granular detergent particles, and coagglomerated perborate particles prepared by the present invention to illustrate the value of this invention. ##SPC9##

The virtual elimination of particles smaller than 35 mesh remarkably reduces the segregation tendencies of the sodium perborate.

EXAMPLE II

Three hundred pounds of sodium perborate powder having a particle size distribution (as in Example I) were added to a baffled mixer. To this mixture was added 300 pounds of a spray-dried granular detergent with a particle size distribution (as in Example I).

The granular mixture was dry mixed in a rotating baffled drum. As the drum was rotating, 68 pounds of a slurry composed of 97.75 percent water and 2.25 percent of a polymerized acrylic acid agglomerating agent having as a fundamental repeating unit,

was uniformly sprayed into the agitating dry mixture.

This specific material was obtained from B. F. Goodrich Chemical Company as Carbopol. Properties of this material are described in B. F. Goodrich Service Bulletin GC-36 entitled "Carbopol Water-Soluble Resins." The slurry was prepared by mixing 1.53 pounds of Carbopol with 66.47 pounds of water. The 68 pounds of slurry were sprayed on in the manner described in Example I. The resultant agglomerated mixture contained 0.23 percent agglomerating agent, 9.97 percent water, 44.9 percent sodium perborate, and 44.9 percent granular detergent.

During the spraying operation, samples were taken as in Example I and analyzed for particle size distribution in the prescribed way. Similar observations were observed as in Example I. The small perborate particles were coagglomerated with the spray-dried detergent granules to very substantially reduce the level of small particles.

EXAMPLE III

Three hundred pounds of a sodium perborate powder having a particle size distribution, as described in Example I, were added to a baffled mixer. To this mixer were added 300 pounds of a spray-dried granulated detergent composition having a particle size distribution as described in Example I. The granular mixture of these two materials was dry-mixed by rotating the baffled drum mixer.

As the drum was rotating, a slurry of 93 percent water and 7 percent of Instant Clearjel, a cross-linked pre-gelatinized amylopectin was uniformly sprayed into the agitating dry mixture. This material, Instant Clearjel, was obtained from National Starch and Chemical Corporation, and is described in the Company's No. 241 Technical Bulletin. The slurry was prepared by mixing 4.8 pounds of the Instant Clearjel powdered material with 63.2 pounds of water. General physical property descriptions of the slurry are similar to those in Example I. Sixty-eight pounds of slurry was uniformly sprayed into the drum mixture in a procedure as described in Example I. The resultant mixture contained 0.72 percent Instant Clearjel, 9.48 percent water, 44.9 percent sodium perborate, and 44.9 percent spray-dried granule detergent. During the spraying operation, samples were taken and removed from the mixer as described in Example I. The samples were analyzed and the particle size distributions were determined. It was observed that the small perborate particles were coagglomerated with the spray-dried detergent granules to significantly reduce the level of small particles as had been previously observed.

EXAMPLE IV

The procedure is similar to the procedure in Example I. As the drum was rotating, 68 pounds of a slurry composed of 94.6 percent water and 5.4 percent Purity HPC agglomerating agent was uniformly sprayed into the agitating dry mixture. Purity HPC was obtained from the National Starch and Chemical Corporation. It is an amylopectin food starch derived from waxy maize. The slurry was prepared by mixing together 3.7 pounds of Purity HPC and 64.3 pounds of water. The slurry was sprayed on in the manner as described in Example I. During the spraying operation, samples were taken as in Example I, and analyzed for particle size distribution. Similar observations were made as in Example I, and it was concluded that the small perborate particles were coagglomerated to the spray-dried detergent granules. The resultant coagglomerated perborate particles contained 0.55 percent Purity HPC, 9.65 percent water, 44.9 percent granular detergent material, and 44.9 percent sodium perborate.

EXAMPLE V

The following laundry composition is an example of a preferred embodiment of this invention. It is a nonsegregating laundry product combining excellent bleaching and cleaning properties.

20% Sodium linear tridecylbenzene

40% Sodium tripolyphosphate

14% Sodium sulfate

6% Sodium silicate

10% Water

10% Coagglomerated sodium perborate product of Example I

The sodium tripolyphosphate can be replaced with an equal weight percent of sodium nitrilotriacetate and an excellent composition is obtained.

EXAMPLE VI

A dry mixture of sodium perborate granules and spray-dried granular detergent were mixed together as described in Example I. Five hundred grams of the granular detergent material were mixed woth 500 grams of sodium perborate following the general procedure described in Example I. As the drum was rotating, 100 grams of a slurry composed of 5 grams of a polymerized ethylene oxide polymer agglomerating agent and 95 grams were sprayed onto the mixture. The polymerized ethylene oxide polymer was obtained from Union Carbide Company under the trade name "Polyox" and is a nonionic poly(ethylene oxide) homopolymer ranging in molecular weight from several hundred thousand to over five million. The material is described in a company bulletin Poly-Ox Water Soluble Resins. The same coagglomerated products were formed as in Example I, composed of 0.45 percent agglomerating agent, 8.55 percent water, 45.5 percent sodium perborate and 45.5 percent spray-dried detergent composition.

EXAMPLE VII

Five hundred grams of a granular detergent material were mixed with 500 grams of sodium perborate particles in a baffled mix drum, as described in Example I. One hundred grams of a slurry composed of 15 grams of an agglomerating agent which is a linear copolymer prepared by reacting ethylene with maleic anhydride and 85 grams of water were sprayed into the drum as the drum was rotating. The copolymer is an anhydride having a viscosity of 5.0 cps (2 percent solution at normal product pH). The specific material used is EMA-21 obtained from Monsanto Company and is described in Technical Bulletin 1-261 "EMA* (*EMA is a trademark of Monsanto Company.) Ethylene Maleic Anhydride Resins."

Analysis of coagglomerated perborate product showed general particle size distribution as described in Example I. The coagglomerated perborate product was composed of 1.36 percent agglomerating agent, 7.64 percent water, 45.5 percent sodium perborate and 45.5 percent spray-dried detergent composition.

EXAMPLE VIII

Following the general procedure of Example I, 500 grams of a granular detergent material and 500 grams of sodium perborate were mechanically mixed in a baffled mix drum. One hundred grams of slurry composed of 7 grams of carboxy methyl cellulose agglomerating agent and 93 grams of water were sprayed into the mixture as the drum rotated. The carboxy methyl cellulose was obtained from the Dow Cehmical Company as Methocel. The final coagglomerated perborate composition was composed of 0.63 percent methyl cellulose, 8.37 percent water, 45.5 percent sodium perborate and 45.5 percent spray-dried detergent composition.

EXAMPLE IX

Following the general procedure of Example I, 500 grams of a spray-dried granular detergent were mixed with 500 grams of sodium perborate particles, in a baffled mixer. One hundred grams of a slurry composed of 10 grams of starch agglomerating agent and 90 grams of water were sprayed into the drum as the drum rotated. The final coagglomerated perborate composition was composed of 0.91 percent coagglomerating agent, 8.09 percent water, 45.5 percent sodium perborate, and 45.5 percent spray-dried detergent composition. Particle size distribution was generally the same as Example I.

EXAMPLE X

Following the general procedure of Example I, 500 grams of a spray-dried granular detergent material and 500 grams of sodium perborate were charged to a baffled mix drum. One hundred grams of a slurry composed of 5 grams of cross-linked pregelatinized amylopectin agglomerating agent (Amaizo 727-A) and 95 grams of water were sprayed into the tumbling mixture. The agglomerating agent was obtained from American Maize Products Company. Coagglomeration occurred uniformly and the general particle size distribution of Example I was achieved. The coagglomerated perborate composition was composed of 0.45 percent amylopectin agglomerating agent, 8.55 percent water, 45.5 percent sodium perborate and 45.5 percent spray-dried detergent composition.

EXAMPLE XI

Following the general procedure of Example I, 500 grams of a spray-dried granular detergent material and 500 grams of sodium perborate were added to a baffled mixer. Into the mixer was sprayed 100 grams of a slurry composed of 25 grams of corn starch (57 percent amylose, 43 percent amylopectin) and 75 grams of water. The corn starch was obtained as Amylon from National Starch and Chemical Corporation. Uniform coagglomeration resulted in particle size distribution similar to Example I and the product was composed of 2.3 percent agglomerating agent, 6.7 percent water, 45.5 percent spray-dried detergent composition, and 45.5 percent sodium perborate.

EXAMPLE XII

Following the general procedure of Example I, 500 grams of a granular detergent material were mixed with 500 grams of sodium perborate in a baffled mixer. As the mixer was rotating, 100 grams of a slurry consisting of 1.1 gram of polysaccharide gum agglomerating agent and 98.9 grams of water was sprayed into the mixer. The polysaccharide gum material was obtained from the Kelco Company and is identified in Bulletin DB-14 as Kelgum. Uniform coagglomeration resulted in particle size distribution similar to Example I; the product was composed of 0.1 percent agglomerating agent, 8.9 percent water, 45.5 percent sodium perborate, 45.5 percent spray-dried detergent composition.

EXAMPLE XIII

In the procedure of Example VI, similar results are obtained when 500 grams of sodium citrate granules are used in place of the spray-dried detergent composition.

EXAMPLE XIV

In the procedure of Example VI, similar results are obtained when sodium nitrilotriacetate granules are used in place of the spray-dried detergent composition.

EXAMPLE XV

In the procedure of Example VI, similar results are obtained when sodium pyrophosphate granules are used in place of the spray-dried detergent granules.

EXAMPLES XVI

In the procedure of Example VI, similar results are obtained when sodium bicarbonate granules are used in place of the spray-dried detergent granules.

EXAMPLES XVII

In the procedure of Example VI, similar results are obtained when sodium phosphate granules are used in place of the spray-dried detergent granules.

EXAMPLE XVIII

In the procedure of Example VI, similar results are obtained when sodium thiosulfate granules are used in place of the spray-dried detergent granules.

EXAMPLE XIX

In the procedure of Example VI, similar results are obtained when sodium borate granules are used in place of the spray-dried detergent granules

EXAMPLE XX

In the procedure of Example VI similar results are obtained when sodium sulfate granules are used in place of the spray-dried detergent granules.

The coagglomerated perborate composition described herein can be readily dyed to form aesthetically attractive speckles for incorporation into ordinary spray-dried granular detergent compositions.

All proportions and ratios given herein are on a weight basis unless otherwise specified.

In preparing spray-dried granular detergent compositions as described herein, the preferred proportion of organic synthetic detergent to the detergency builder is in the range of 2:1 to 1:10.

The term "coagglomerant " is used in the description of this invention to mean any solid granular product or composition with which the sodium perborate bleaching agent is to be coagglomerated.

The improved enzyme effectiveness and stability results enjoyed with the coagglomerated concentrated sodium perborate composition of this invention are demonstrated and described below.

The following spray dried laundry detergent composition was prepared:

12.9% Sodium tridecyl benzene sulfonate

45.5% Sodium tripolyphosphate

15.6% Sodium sulfate

5.4% Sodium silicate

4.0% Sodium perborate NaBO.sub.3 .sup.. 4H.sub.2 O (added as described below)

8.7% Water

3.43% Miscellaneous

4.3% Sodium fatty acid soap consisting of 3 parts sodium tallow soap and 1 part marine fatty acid soap

0.17% Enzyme composition described below

The enzyme composition was prepared by blending the following materials. The enzyme powder mixture so prepared had a particle size distribution ranging from Tyler 80 mesh to smaller than Tyler 100 mesh (0.007 inch to smaller than 0.0016 inch) with almost 95 percent smaller than Tyler 80 mesh (0.007 inch):

(1) 14.78 parts of an enzyme preparation comprising 6.86 percent of a .alpha.-amylase having 755,000 amylase activity units per gram, 6.33 percent alkaline protease having about 465,000 protease activity units per gram and the balance inert materials such as calcium sulfate and sodium sulfate; (2) 5.58 parts of an enzyme preparation comprising 5.68 percent of .alpha.-amylase having about 635,000 amylase activity units per gram, 5.10 percent alkaline protease having about 375,000 protease activity units per gram and the balance inert materials such as calcium sulfate and sodium sulfate; (3) 4.78 parts of an enzyme preparation comprising 1.82 percent of .alpha.-amylase having about 200,000 amylase activity units per gram, 5.44 percent of an alkaline protease having about 400,000 protease activity units per gram and the balance inert materials such as calcium sulfate and sodium sulfate; (4) 23.72 parts of an enzyme preparation comprising 16.33 percent alkaline protease having about 1,200,000 protease activity units per gram and the balance inert materials such as sodium and calcium sulfate; (5) 11.14 parts of an enzyme preparation comprising 6.25 percent of an alkaline protease having about 458,000 protease activity units per gram and the balance inert materials such as sodium and calcium sulfate.

In order to provide products for comparison, sodium perborate was added to one composition, Composition A, by fusing 4 percent by weight of the perborate particles to the hot spray-dried granules at the base of the spray tower. This is a conventional way of incorporating fine perborate powders into a spray-dried composition to prevent segregation in a carton.

This invention was practiced to prepare a comparison product, Composition B. In this product, 4 percent by weight of an coagglomerated, concentrated, dust-free sodium perborate composition was prepared by following the precedure of Example I above. The resulting product was dust-free, non-segregating and an excellent laundry product combining both oxidizing bleaching and enzyme activity.

The improved enzyme stability of Composition B containing a preferred embodiment of this invention was shown by an amylase test and an Azocoll test.

The two detergent compositions were separately packaged in cardboard containers and stored at 90.degree. F. and 80 percent relative humidity for 12 days. This represents a severe laboratory evaluation of enzyme-containing detergent products. Enzyme stability was periodically tested as illustrated by the data in the table below.

Amylase enzyme activity was measured of these two compositions, A and B, and the results in Table II indicate clearly the improved stability results of Composition B in comparison to Composition A.

TABLE II

Percent Remaining Activity .sup.1

0 3 6 9 12 days days days days days Composition A 5% 0% 0% 0% 0% Composition B 100% 85% 60% 40% 25% __________________________________________________________________________

An Azocoll test.sup.1 proteolytic activity was also performed and this also revealed a significant directional enzyme stability improvement although not as significant as with amylase activity.

TABLE I --------------------------------------------------------------------------- Percent Remaining Enzyme Activity.sup.1

0 days 3 days 6 days 12 days Composition A 100% 95% 66% 50% Composition B 100% 95% 90% 75% __________________________________________________________________________

as can be readily seen from the data in the table, proteolytic enzyme activity of Composition B was very substantially more evident than Composition A.

The enzymes which can be usefully employed in conjunction with the dust-free concentrated coagglomerated sodium perborate composition of this invention are those mentioned and described in U.S. Pat. No. 3,451,935 and they include proteases, amylases, lipases and the like.

The coagglomerated concentrated dust-free sodium perborate composition employed herein is described in a co-pending application, Ser. No. 889,325 filed Dec. 30, 1969, now abandoned in favor of a Continuation-In-Part Application, Ser. No. 24,329, filed Mar. 31, 1970, now abandoned.

Claims

Having described and illustrated the present invention by test and examples, I claim:

1. An enzyme granular detergent composition having improved enzyme stability which consists essentially of at least one water-soluble organic synthetic detergent, at least one water-soluble detergency builder salt, the proportion by weight of said detergent to said builder being from 10:1 to 1:20; an effective amount of enzyme, and from 0.005 percent to 50 percent by weight of a coagglomerated dust-free concentrated sodium perborate bleaching agent said coagglomerated sodium perborate consisting essentially (1) sodium perborate, (2) a water-soluble polymeric organic agglomerating agent which forms a tacky solution with water at 72.degree. F. and is selected from the group consisting of a linear interpolymer of methyl vinyl ether and maleic anhydride having a specific viscosity of 0.1 - 0.5 as measured on a solution of 1 g. of the copolymer in 100 ml. of MEK at 25.degree. C.; polyacrylic acid; cross-linked, pregelatinized amylopectin; amylopectin; poly(ethylene oxide) homopolymer; linear copolymer of ethylene and maleic anhydride; methyl cellulose; starch; gelatin; and polysaccharide gum, and (3) as a water-soluble coagglomerant a spray-dried granular detergent composition consisting essentially of at least one water-soluble organic synthetic detergent and at least one water-soluble builder salt selected from organic or inorganic sequestering builder salts, the proportion of said detergent to said builder in said perborate coagglomerant being in the range of 5:1 to 1:20.

2. A composition of claim 1 in which the amount coagglomerated perborate is 1 percent to 40 percent.

3. A composition of claim 2 in which the ratio of detergent to builder is 5:1 to 1:10.

4. A coagglomerated sodium perborate composition consisting essentially of (1) sodium perborate, (2) a water-soluble polymeric organic agglomerating agent which forms a tacky solution with water at 72.degree. F. and which is selected from the group consisting of a linear interpolymer of methyl vinyl ether and maleic anhydride having a specific viscosity of 0.1 - 0.5 as measured on a solution of 1 g. of the copolymer in 100 ml. of MEK at 25.degree. C; polyacrylic acid; cross-linked, pre-gelatinized amylopectin; amylopectin; poly(ethylene oxide) homopolymer; linear copolymer of ethylene and maleic anhydride; methyl cellulose; starch; gelatin; and polysaccharide gum, and (3) as a water-soluble coagglomerant a spray-dried granular detergent composition consisting essentially of at least one water-soluble organic synthetic detergent and at least one water-soluble builder salt selected from organic or inorganic sequestering builder salts, the proportion of said detergent to said builder being in the range of 5:1 to 1:20.

5. A nonsegregating granular laundry detergent composition consisting essentially of a water-soluble organic synthetic detergent and a water-soluble detergency builder selected from organic or inorganic sequestering builder salts, the proportion by weight of said detergent to said builder being in the range of 5:1 to 1:20, and from 1 percent to about 60 percent by weight of the composition of a coagglomerated perborate product of claim 4.

6. A process for preparing a coagglomerated sodium perborate composition which comprises the steps of agitating a dry mixture of 1 to 99 percent by weight sodium perborate granules and 1 - 99 percent by weight water-soluble granular coagglomerant selected from the group consisting of sodium sulfates, sodium thiosulfates, carboxymethyl cellulose, starch, an organic synthetic detergent selected from anionic, nonionic, ampholytic, or zwitterionic detergents, a builder salt selected from organic or inorganic sequestering builder salts, or a spray-dried granular detergent composition consisting essentially of at least one water-soluble organic synthetic detergent and at least one water-soluble builder salt selected from organic or inorganic sequestering builder salts, the proportion of said detergent to said builder being in the range of 5:1 to 1:20, and spraying said dry mixture with an aqueous slurry of water-soluble polymeric agglomerating agent which forms a tacky aqueous solution at about 72.degree. F. and which is selected from the group consisting of a linear interpolymer of methyl vinyl ether and maleic anhydride having a specific viscosity of 0.1 - 0.5 as measured on a solution of 1.g of the copolymer in 100 ml. of MEK at 25.degree. C.; polyacrylic acid; cross-linked, pre-gelatinized amylopectin; amylopectin; poly(ethylene oxide) homopolymer; linear copolymer of ethylene and maleic anhydride, methyl cellulose; starch; gelatin; and polysaccharide gum, the concentration of said polymeric agglomerating agent in said aqueous slurry being from 1 to 40 percent by weight, and said slurry having a temperature in the range of 50.degree. F. to 180.degree. F.

7. A process of claim 6 in which said dry mixture consists essentially of 50 - 95 percent sodium perborate granules and 5 - 50 percent of said granular coagglomerant, the concentration of polymeric agglomerating agent in the slurry is 5 - 25 percent and the temperature of the slurry is 70.degree.-160.degree. F.