WO1998038280A1

WO1998038280A1 - Laundry detergent bar comprising aluminum compounds with improved physical properties

Info

Publication number: WO1998038280A1
Application number: PCT/US1997/003065
Authority: WO
Inventors: Kennie Uy Dee; Gerard Abellera Latoga; Noe Ongcoy Hidalgo
Original assignee: The Procter & Gamble Company
Priority date: 1997-02-27
Filing date: 1997-02-27
Publication date: 1998-09-03
Also published as: AU1979097A; CO5031264A1

Abstract

The present invention relates to a process for making a synthetic laundry detergent bar composition comprising aluminum salts, wherein the aluminum salt is added before the phosphate detergency builder is added to the mixture; and wherein the composition comprises at least 10 % anionic synthetic detergent active and wherein the composition is substantially free of siliceous materials. The present invention also relates to bar compositions made by the process described above.

Description

LAUNDRY DETERGENT BAR COMPRISING ALUMINUM COMPOUNDS WITH IMPROVED PHYSICAL PROPERTIES

FIELD OF THE INVENTION This invention relates to a laundry detergent bar composition comprising anionic synthetic detergent active having improved physical properties. The process to make such compositions is also included herein.

BACKGROUND OF THE INVENTION in societies where mechanical washing machines are not common, laundry detergent bars comprising synthetic organic surfactants and detergency builders are used in the laundering of clothes. Technical developments in the field of laundry detergent bars have concerned formulating bars which are effective in cleaning clothes; which have acceptable sudsing characteristics in warm and cool water and in hard and soft water; which have acceptable in-use wear rates, hardness, durability, and feel; which have low smear; and which have a pleasing odor and appearance. Methods for making laundry detergent bars are also well known in the art. Prior art disclosing laundry bars and methods for making laundry bars include: U.S. Pat. 3, 1 78,370, Okenfuss, issued April 1 3, 1 965; and Philippine Pat. 1 3,778, Anderson, issued September 23, 1 980.

It has now been found that laundry bar compositions comprising aluminum salts improve the hardness of the bar, thereby retaining the structural integrity during use and transportation. Furthermore, such compositions have reduced bar solubility, wherein it is harder for the bar to dissolve after becoming wet during the washing process.

SUMMARY OF THE INVENTION The present invention relates to a process for making a synthetic laundry detergent bar composition comprising the steps of: a. forming a mixture comprising a neutralized anionic synthetic detergent surfactant, a phosphate detergency builder, optionally other ingredients, and aluminum salts, wherein substantially all of the phosphate detergency builder is added to the mixture after the aluminum salt; and b. forming into bars; wherein the bar composition comprises at least 10% anionic synthetic detergent surfactant and wherein the bar composition is substantially free of siliceous materials.

The present invention also relates to bar compositions made by the process described above.

DETAILED DESCRIPTION OF THE INVENTION While this specification concludes with claims distinctly pointing out and particularly claiming that which is regarded as the invention, it is believed that the invention can be better understood through a careful reading of the following detailed description of the invention. In this specification, all percentages, ratios, and proportions are by weight, all temperatures are expressed in degrees Celsius, molecular weights are in weight average, and the decimal is represented by the point (.), unless otherwise indicated. All documents referenced herein are incorporated by reference. Anionic synthetic detergent surfactants

The composition of the present invention comprises at least 1 0% anionic synthetic detergent surfactant, by weight of the total bar composition. Preferably the bar composition comprises from about 1 5% to about 30%, more preferably more preferably from about 20% to about 25% anionic synthetic detergent surfactant, by weight of the total bar composition.

Anionic synthetic detergent surfactants which are suitable for use herein include the water-soluble salts, preferably the alkali metal, ammonium and alkylolammonium salts of organic sulfuric reaction products having in their molecular structure an alkyl group containing from about 1 0 to about 20 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 surfactants are the sodium and potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (Cs-1 8 carbon atoms) such as those produced by reducing the glycerides of tallow or coconut oil; and the sodium and potassium alkylbenzene sulfonates in which the alkyl group contains from about 9 to about 1 5 carbon atoms, in straight chain or branched chain configuration, e.g., those of the type described in U.S. Patents 2,220,099 and 2,477,383. Especially valuable are linear straight chain alkylbenzene sulfonates in which the average number of carbon atoms in the alkyl group is from about 1 0 to 1 8, abbreviated as C-| 0-1 8 ^LAS- The alkali metal salts, particularly the sodium salts of these surfactants are preferred. Alkylbenzene sulfonates and processes for making them are disclosed in U.S. Patent Nos. 2,220,099 and 2,477,383. Mixtures of the above types of anionic surfactants are preferred.

Specifically, preferred anionic surfactants are C-| Q-1 8 linear alkyl benzene sulfonates, C-| 0-1 8 ^a' sulfates, and mixtures thereof. One preferred composition comprises from about 1 0% to about 30% LAS, by weight of the total bar composition for a primarily LAS-surfactant based bar. Another preferred composition comprises a mixture of LAS:alkyl sulfate in a ratio of from about 1 0:90 to about 50:50, preferably from about 20:80 to about 40:60. Phosphate Detergency Builder

The laundry bars of the invention contain at least 3%, preferably from about 5% to about 50%, more preferably from about 1 0% to about 30% phosphate detergency builder, by weight of the total bar composition. These detergency builders can be, for example, water-soluble alkali-metal salts of phosphate, pyrophosphates, orthophosphates, tripolyphosphates, higher polyphosphates, and mixtures thereof. Preferred builders are a water-soluble alkali-metal salt of tripolyphosphate, and a mixture of tripolyphosphate and pyrophosphate. Especially preferred examples of builders include sodium tripolyphosphates (STPP) and tetra sodium pyrophosphates (TSPP), and mixtures thereof.

In the present invention, substantially all of the phosphate detergency builder is added after the addition of aluminum salt. Preferably, this means at least about 99% of the phosphate detergency builder is added after the aluminum salt. Aluminum Salts

Aluminum salts which are used in the bars of this invention are water soluble aluminum salts and aluminates. The aluminum salts can be hydrated or anhydrous. Preferred aluminum salts include AI2 (SO4>3, Al2<NO3)3, AICI3, AI(CH2CO2)3 and NaAIO2- Al₂ (804)3 ^{is ost} preferred. The Aluminum salts are preferably in a fine powder form, preferably from about 100 to about 350 mesh, more preferably from about 200 to 300 mesh. The bar composition comprises from about 0.5% to about 1 0% aluminum salts, by weight of the total bar composition, preferably from about 1 % to about 8%, and most preferably from about 2% to about 6%. Siliceous materials

The bars of the present invention are substantially free of siliceous materials, preferably containing less than about 1 %, more preferably not containing any in the bar composition. Siliceous materials include silica in finely divided form, silicates, polymeric silicates and sodium aluminosilicates, and clays. Adjunct Ingredients The detergent bars of the present invention can contain optional surfactants In addition to the anionic synthetic detergent surfactants described above. A typical listing of the classes and species of optional surfactants, (e.g. nonionic, zwitterionic and amphoteric surfactants) optional alkaline builders such as sodium carbonate trisodium phosphate, etc. and other ingredients useful herein appears in U.S. Pat. No. 3,664,961 , issued to Norris on May 23, 1 972, and EP 550,652, published on April 1 6, 1 992. Such optional surfactants, if present, can be included at levels up to a total of about 1 0%, preferably about 0.5% to about 3%, by weight of the total bar composition. Other anionic synthetic surfactants suitable for use herein are 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. Preparation of alkyl glyceryl ether sulfonates are described in detail in U.S. Pat. 3,024,273, Whyte et al., issued March 6, 1 962.

In addition, suitable anionic synthetic surfactants include the water- soluble salts of esters of alpha-sulfonated fatty acids containing from about 6 to 20 carbon atoms in the fatty acid group and from about 1 to 1 0 carbon atoms in the ester group; water-soluble salts of 2-acyloxyalkane-1 -sulfonic acids containing from about 2 to 9 carbon atoms in the acyl group and from about 9 to about 23 carbon atoms in the alkane moiety; water-soluble salts of olefin and paraffin sulfonates containing from about 1 2 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.

Amine Oxides are excellent cosurfactants that may be used in conjunction with the present invention. Preferred types are C1 2-C1 8 amine oxides, preferably C1 4. If included, the level of amine oxide in the final bar composition is from about 1 % to about 1 0%, preferably, from about 2% to about 5%.

Other anionic synthetic surfactants suitable for use herein as additional optional surfactants are 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. Preparation of alkyl glyceryl ether sulfonates are described in detail in U.S. Pat. 3,024,273, Whyte et al., issued March 6, 1 962.

In addition, optional anionic synthetic surfactants include the water- soluble salts of esters of alpha-sulfonated fatty acids containing from about 6 to 20 carbon atoms in the fatty acid group and from about 1 to 1 0 carbon atoms in the ester group; water-soluble salts of 2-acyloxyalkane-1 -sulfonic acids containing from about 2 to 9 carbon atoms in the acyl group and from about 9 to about 23 carbon atoms in the alkane moiety; water-soluble salts of olefin and paraffin sulfonates containing from about 1 2 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.

In addition, a hydrotrope, or mixture of hydrotropes, may be present in the laundry detergent bar. Preferred hydrotropes include the alkali metal, preferably sodium, salts of toluene sulfonate, xylene sulfonate, cumene sulfonate, sulfosuccinate, and mixtures thereof. Preferably, the hydrotrope is added to the linear alkyl benzene sulfonic acid prior to its neutralization. The hydrotrope, if present, will preferably be present at from about 0.5% to about 5% of the laundry detergent bar.

The composition can optionally contain in addition to the phosphate detergency builder, a non-phosphate detergent builder. Specific examples of non-phosphate, inorganic detergency builders include water-soluble inorganic carbonate and bicarbonate salts. The alkali metal (e.g., sodium and potassium) carbonates and bicarbonates are particularly useful herein. Other specifically preferred examples of builders include polycarboxylates. Sodium carbonate, another optional ingredient, is particularly preferred as a neutralizing inorganic salt for an acid precursor of an anionic surfactant used in such compositions, such as the alkyl ether sulfuric acid and alkylbenzene sulfonic acid. Co-polymers of acrylic acid and maleic acid are preferred in the subject compositions as auxiliary builders. Soil suspending agents can be used. Soil suspending agents can also include water-soluble salts of carboxymethylcellulose and carboxyhydroxymethylcellulose. A preferred soil suspending agent is an acrylic/maleic copolymer, commercially available as Sokolan^®, from BASF Corp. Other soil suspending agents include polyethylene glycols having a molecular weight of about 400 to 1 0,000, and ethoxylated mono- and polyamines, and quaternary salts thereof. If included, it can be at levels up to about 5%, preferably about 0.1 -1 %.

The bleach agent in the detergent composition, when included, is preferably at a level from about 0.1 0% to about 60% by weight; more preferably, from about 1 % to about 50%; most preferably, from about 1 % to about 20%. The bleach agents used herein can be any of the bleach agents useful for detergent compositions in textile cleaning, hard surface cleaning, or other cleaning purposes that are now known or become known. Mixtures of bleach agents can also be used. A useful bleach agent that can be used encompasses percarboxylic acid bleach agents and salts thereof. Suitable examples of this class of agents include magnesium monoperoxyphthalate hexahydrate, the magnesium salt of metachloro perbenzoic acid, 4-nonylamino-4- oxoperoxybutyric acid and diperoxydodecanedioic acid. Such bleach agents are disclosed in U.S. Patent 4,483,781 , Hartman, issued November 20,

1 984, U.S. Patent Application 740,446, Burns et al, filed June 3, 1 985, European Patent Application 0, 1 33,354, Banks et al, published February 20,

1 985, and U.S. Patent 4,41 2,934, Chung et al, issued November 1 , 1 983. Highly preferred bleach agents also include 6-nonylamino-6-oxoperoxycaproic acid as described in U.S. Patent 4,634,551 , issued January 6, 1 987 to Burns et al.

Other peroxygen bleach agents can also be used. Suitable peroxygen bleach compounds include sodium carbonate peroxyhydrate and equivalent "percarbonate" bleaches, sodium pyrophosphate peroxyhydrate, urea peroxyhydrate, and sodium peroxide. Persulfate bleach (e.g., OXONE, manufactured commercially by DuPont) can also be used.

Bleach agents other than oxygen bleach agents are also known in the art and can be utilized herein. One type of non-oxygen bleach agent of particular interest includes photoactivated bleach agents such as the sulfonated zinc and/or aluminum phthalocyanines. See U.S. Patent 4,033,71 8, issued July 5, 1 977 to Holcombe et al. If used, detergent compositions will typically contain from about 0.025% to about 1 .25%, by weight, of such bleaches, especially sulfonate zinc phthalocyanine. An optional useful percarbonate bleach comprises dry particles having an average particle size in the range from about 500 micrometers to about 1 ,000 micrometers, not more than about 1 0% by weight of said particles being smaller than about 200 micrometers and not more than about 1 0% by weight of said particles being larger than about 1 ,250 micrometers. Optionally, the percarbonate can be coated with silicate, borate or water- soluble surfactants. Percarbonate is available from various commercial sources such as FMC, Solvay and Tokai Denka.

When included, the preferred bleach agent for the present invention are those peroxygen bleaching compounds which are capable of yielding hydrogen peroxide in an aqueous solution. These compounds are well known in the art and include hydrogen peroxide and the alkali metal peroxides, organic peroxide bleaching compounds such as urea peroxide, and inorganic persalt bleaching compounds, such as the alkali metal perborates, percarbonates, perphosphates, and the like. Mixtures of two or more such bleaching compounds can also be used, if desired.

Preferred peroxygen bleaching compounds to be used in the present invention include sodium perborate, commercially available in the form of mono- and tetra-hydrates, sodium carbonate peroxyhydrate, sodium pyrophosphate peroxyhydrate, urea peroxyhydrate, and sodium peroxide. Particular preferred are sodium perborate tetrahydrate, and especially, sodium perborate monohydrate. Sodium perborate monohydrate is especially preferred because it is very stable during storage and yet still dissolves very quickly in the bleaching solution.

Another optional component of the present invention is a detergent chelant. Such chelants are able to sequester and chelate alkali cations (such as sodium, lithium and potassium), alkali metal earth cations (such as magnesium and calcium), and most importantly, heavy metal cations such as iron, manganese, zinc and aluminum. Preferred cations include sodium, magnesium, zinc, and mixtures thereof. The detergent chelant is preferably a phosphonate chelant, particularly one selected from the group consisting of diethylenetriamine penta(methylene phosphonic acid), ethylene diamine tetra(methylene phosphonic acid), and mixtures and salts and complexes thereof, and an acetate chelant, particularly one selected from the group consisting of diethylenetriamine penta(acetic acid), ethylene diamine tetra(acetic acid), and mixtures and salts and complexes thereof. Particularly preferred are sodium, zinc, magnesium, and aluminum salts and complexes of diethylenetriamine penta(methylene phosphonate) diethylenetriamine penta (acetate), and mixtures thereof.

Preferably such salts or complexes have a molar ratio of metal ion to chelant molecule of at least 1 : 1 , preferably at least 2: 1 . The detergent chelant can be included in the laundry bar at a level up to about 5%, preferably from about 0.1 % to about 3%, more preferably from about 0.2% to about 2%, most preferably from about 0.5% to about 1 .0%.

Another optional component of the laundry bar is fatty alcohol having an alkyl chain of 8 to 22 carbon atoms, more preferably from 1 2 to 1 8 carbon atoms. A preferred fatty alcohol has an alkyl chain predominantly containing from 1 6 to 1 8 carbon atoms, so-called "high-cut fatty alcohol," which can exhibit less base odor of fatty alcohol relative to broad cut fatty alcohols. Typically fatty alcohol, if any, is present in the laundry bar at up to a level of 1 0%, more preferably from about 0.75% to about 6%, most preferably from about 2% to about 5%. The fatty alcohol is generally added to a laundry bar as free fatty alcohol. However, low levels of fatty alcohol can be introduced into the bars as impurities or as unreacted starting material. For example, laundry bars based on coconut fatty alkyl sulfate can contain, as unreacted starting material, from 0.1 % to 3.5%, more typically from 2% to 3%, by weight of free coconut fatty alcohol on a coconut fatty alkyl sulfate basis.

Another optional component in the laundry bar is a dye transfer inhibiting (DTI) ingredient to prevent diminishing of color fidelity and intensity in fabrics. A preferred DTI ingredient can include polymeric DTI materials capable of binding fugitive dyes to prevent them from depositing on the fabrics, and decolorization DTI materials capable of decolorizing the fugitives dye by oxidation. An example of a decolorization DTI is hydrogen peroxide or a source of hydrogen peroxide, such as percarbonate or perborate. „ Non- limiting examples of polymeric DTI materials include polyvinylpyrridine N- oxide, polyvinylpyrrolidone (PVP), PVP-polyvinylimidazole copolymer, and mixtures thereof. Copolymers of N-vinylpyrrolidone and N-vinylimidazole polymers (referred to as "PVPI") are also preferred for use herein. The amount of DTI included in the subject compositions, if any, is about 0.05- 5%, preferably about 0.2-2%.

Another optional component in the laundry bar is a fabric softener component. Such materials can be used, if any, at levels of about 0.1 % to 5%, more preferably from 0.3% to 3%, and can include: amines of the formula R4R5R6N, wherein R4 is C5 to C22 hydrocarbyl, R5 and Rβ are independently C 1 to C1 0 hydrocarbyl. One preferred amine is ditallowmethyl amine; complexes of such amines with fatty acid of the formula R7COOH, wherein R7 is C9 to C22 hydrocarbyl, as disclosed in EP No. 0, 1 33,804; complexes of such amines with phosphate esters of the formula RsO- P(O)(OH)-OR9 and HO-P(O)(OH)-OR9, wherein Rs and R9 are independently Ci to C20 alkyl of alkyl ethoxylate of the formula -alkyl-(OCH2CH2); cyclic amines such as imidazolines of the general formula 1 -(higher alkyl) amido (lower alkyl)-2-(higher alkyDimidazoline, where higher alkyl is from 1 2 to 22 carbons and lower alkyl is from 1 to 4 carbons, such as described in UK Patent Application GB 2, 1 73,827; and quaternary ammonium compounds of the formula R1 0R1 1 ^R1 2^R1 3^{N + X~} _* wherein R1 0 is alkyl having 8 to 20 carbons, Ri 1 is alkyl having 1 to 1 0 carbons, R1 2 and R1 3 are alkyl having 1 to 4 carbons, preferably methyl, and X is an anion, preferably CI^" or Br, such as C 1 2-1 3 alkyl trimethyl ammonium chloride.

Sodium sulfate is a well-known filler that is compatible with the compositions of this invention. It can be a by-product of the surfactant sulfation and sulfonation processes, or it can be added separately. Calcium carbonate (also known as Calcarb) is also a well known and often used filler component of laundry bars. Filler materials are typically used, if included, at levels up to 40%, preferably from about 5% to about 25%. Optical brighteners are also optional ingredients in laundry bars of the present invention. Preferred optical brighteners are diamino stilbene, distyrilbiphenyl-type optical brighteners. Preferred as examples of such brighteners are 4,4'-bis{[4-anilino-6-bis(2-hydoxyethyl) amino-1 ,3,5-trizin-2- yl]amino}stilbene-2,2'-disulfonic acid disodium salt, 4-4'-bis(2-sulfostyryl) biphenyl and 4,4'-bis[(4-anilino-6-morpholino-1 ,3,5-triazin-2-yl) amino]stilbene-2,2'-disulfonic acid disodium salt. Such optical brighteners, or mixtures thereof, can be used at levels in the bar of from about 0.05% - 1 .0%.

Dyes, pigments, germicides, and perfumes can also be added to the bar composition. If included, they are typically at levels up to about 0.5%.

Another optional component of the subject invention composition is a photobleach material, particularly phthalocyanine photobleaches which are described in U.S. Patent 4,033,71 8 issued July 5, 1 977, incorporated herein by reference. Preferred photobleaches are metal phthalocyanine compounds, the metal preferably having a valance of + 2 or + 3; zinc and aluminum are preferred metals. Such photobleaches are available, for example, under the tradename TINOLUS or as zinc phthalocyanine sulfonate. The photobleach components, if included, are typically in the subject compositions at levels up to about 0.02%, preferably from about 0.001 % to about 0.01 5%, more preferably from about 0.002% to about 0.01 %.

Another useful optional component of the subject compositions are detergent enzymes. Particularly preferred are lipase, protease, amylase, and mixtures thereof. Enzymes, if included, are typically at levels up to about 5%, preferably about 0.5-3%. Moisture

The final bar composition should have no more than about 1 5% moisture. The moisture level of the total bar composition can be determined by any methods known in the art by one skilled in the area of laundry bar compositions. One common method is the Bidwell Sterling Distillation method. Another known method is the Karl Fischer Moisture Titration Method. See AOCS official method Dd2a-59 issue 93 and AOCS official method Dd2b-59 issue 89. Bar Physical Properties

The bars of the present invention have improved physical properties, including improved in-process and aged hardness of the bar as well as reduced solubility in water during washing.

The bars of the present invention are sufficiently hard. A preferred test method measures bar hardness after three weeks of aging. Bars are aged for three weeks at 80° F/80 relative humidity (RH). To measure the bar hardness, a needle with a point angle of 43 ° attached to a force gauge (Control International, Lincolnwood, IL, USA) was forced onto the plane of the bar surface to a depth of 5.8 mm. A preferred bar hardness reading of laundry bar compositions using this test method is about 55-70 lbs. Bars of the present invention fall within the range. Another method to measure bar hardness is to measure the penetration of a needle through the bar surface under a standard weight for 5 seconds using a cone penetrometer. One such penetrometer is made by Associated Instrument Manufacturers India Pvt. Ltd. (Model number AIM 51 2) . The weight of the rod and the cone is 149 grams and an additional 50 gram weight is placed on the cone. The penetration reading of a fresh bar made as per the present invention will typically be about 20-30 ( 1 /1 0 mm) and 1 5-20 ( 1 /1 0 mm) after 40 minutes. Bars aged about 3 days at ambient conditions will typically have a bar penetration reading of about 5-1 2 ( 1 /1 0 mm).

Another physical property of interest is the bar solubility in water. One method of determining the bar solubility is to submerge a bar having the following dimensions 75mm x 55mm in 250 ml of water in a beaker for 2 hours, drying the bar at 60 deg. C for 2 hours and then weighing the bar. To have acceptable bar solubility, the difference in weight should be about 1 5- 20 grams for a 1 25 gram bar (1 2-1 6% of the original weight of the bar), more preferably 5-1 5 grams (4-1 2% of the original weight of the bar). Processing

The detergent laundry bars of the present invention can be processed in conventional soap or detergent bar making equipment with some or all of the following key equipment: blender/mixer, mill or refining plodder, two- stage vacuum plodder, logo printer/cutter, cooling tunnel and wrapper. In a typical process the raw materials are mixed in the blender. Alkyl benzene sulfonic acid is reacted with alkaline inorganic salts to complete neutralization, the amount of alkaline inorganic salt being at least sufficient to completely neutralize the acid. Once the neutralization reaction is completed, the aluminum salt is added but before the phosphate builder is added to the mixture. The aluminum salt should only be added after the neutralization of the acid form of anionic synthetic detergent surfactant. Where pre- neutralized anionic surfactant is used exclusively, the Aluminum salt can be added either before or after the surfactant is added to the mixer. Substantially all of the phosphate used in the composition is added after the aluminum salt. Then other optional surfactants followed by any additional optional components such as chelants are added. The composition is substantially free of siliceous materials. The mixing can take from one minute to one hour, with the usual mixing time being from about two to twenty minutes. The blender mix is charged to a surge tank. The product is conveyed from the surge tank to the mill or refining plodder via a multi-worm conveyor.

After milling or preliminary plodding, the product is then conveyed to a two-stage vacuum plodder, operating at high vacuum, e.g. 600 to 740 mm of mercury vacuum, so that entrapped air/gas is removed. The product is extruded and cut to the desired bar length, and printed with the product brand name. The printed bar can be cooled, for example in a cooling tunnel, before it is wrapped, cased, and sent to storage.

A preferred laundry bar composition is made by the following method: The raw materials are first mixed in a blender. Sodium carbonate and pre- neutralized CFAS is mixed for about 1 -2 minutes, in order to make a mixed anionic LAS/Alkyl Sulfate surfactant bar composition. This is followed by the addition of linear alkyl benzene sulfonic acid and sulfuric acid (if present in the formulation). The acids are then completely neutralized by the sodium carbonate in the seat of the blender. (The amount of sodium carbonate should be at least an amount sufficient to neutralize the acids.) The materials are mixed for an additional 1 -2 minutes after dosing. Once the neutralization reaction is completed, a chelant, if present is added, followed by aluminum salt and other optional surfactants, STPP and any other additional optional components. The aluminum salt must be added before the STPP is added. (Substantially all of the STPP is added after the aluminum salt.) The mixing can take from one minute to one hour, with the usual mixing time being from about five to ten minutes. As one of the last ingredients, bleach and enzymes are added to the mixture and then mixed for an additional one to five minutes. The composition is substantially free of siliceous materials. The blender mix is charged to a surge tank. The product is conveyed from the surge tank to the mill or refining plodder via a multi-worm conveyor.

After milling or preliminary plodding, the product is then conveyed to a two-stage vacuum plodder, operating at high vacuum, e.g. 600 to 740 mm of mercury vacuum, so that entrapped air is removed. The product is extruded and cut to the desired bar length, and printed with the product brand name. The printed bar can be cooled, for example in a cooling tunnel, before it is wrapped, cased, and sent to storage.

Examples of the invention are set forth hereinafter by way of illustration and are not intended to be in any way limiting of the invention. The invention is illustrated by the following non-limiting examples. All parts and percentages herein are by weight unless otherwise stated.

EXAMPLE I Various bar compositions (Examples A through C) are prepared by the process of the invention.

B

( (wweeiigghht percent)

Linear alkyl benzene sulfonate 1 2.5 0 8.5

Coco fatty alcohol sulfate 1 2.5 1 7.5 1 6.0

C1 4 Amine Oxide 0 5.0 0

Soda Ash 14 14 1 5

Sulfuric acid 2.5 2.5 2.5

Sodium Tripolyphosphate 1 1 .6 1 1 .6 1 1 .6

Calcium carbonate 36 32 22

Coco fatty alcohol 1 1 1

Tiθ2 1 1 1

Perborate Monohydrate 2.25 4.5 10

Aluminum sulfate hydrate 5 7.5 10

Fluorescent agents 0.2 0.2 0.2

Perfume 0.35 0.35 0.35

Moisture (final comp.) 3.5 4.5 6.0

Diethylenetriamine pentaacetate 0.9 0.9 0.9 Other conventional ingredients Balance Balance Balance

1 00 100 100

EXAMPLE II

The following composition is prepared by the process of the invention:

(weight percent)

Linear alkyl benzene sulfonate 1 9

Soda Ash 1 3.7 Sodium Tripolyphosphate 1 4

Calcium carbonate 40

Sodium Sulfate 3

Aluminum sulfate hydrate 5.6

Fluorescent agents 0.2 Perfume 0.35

Moisture (final comp.) 6

Other conventional ingredients Balance

100

Claims

WHAT IS CLAIMED IS:

1 . A process for making a synthetic laundry detergent bar composition comprising the steps of: a. forming a mixture comprising a neutralized anionic synthetic detergent surfactant, a phosphate detergency builder, optionally other ingredients, and aluminum salt, wherein substantially all of the phosphate detergency builder is added to the mixture after the aluminum salt; and b. forming into bars; wherein the bar composition comprises at least 1 0% anionic synthetic detergent surfactant, by weight of the bar composition; and wherein the bar composition is substantially free of siliceous materials.

2. A synthetic laundry detergent bar composition made by the process of Claim 1 , wherein the anionic synthetic detergent active is selected from the group consisting of C-| Q-1 8 linear alkyl benzene sulfonates, C l 0-1 8 alkyl sulfates, and mixtures thereof.

3. A synthetic laundry detergent bar composition made by the process of Claim 1 , comprising:

(a) from about 1 5% to about 30% anionic synthetic detergent active selected from the group consisting of C -| 0-1 8 linear alkyl benzene sulfonates, C10-I 8 alkyl sulfates, and mixtures thereof;

(b) at least 3% phosphate detergency builder; and

(c) from about 0.5% to about 1 0% aluminum salt.

4. A synthetic laundry detergent bar composition made by the process of Claim 1 , wherein the aluminum salt is selected from the group comprising AI2 (804)3, Al2(NO3>3, AICI3, AI(CH2CO2>3, NaAIO2, and mixtures thereof.

5. A synthetic laundry detergent bar composition made by the process of Claim 1 , wherein the phosphate detergency builder is selected from the group consisting of water-soluble alkali metal salts of phosphate, pyrophosphate, orthophosphate, tripolyphosphate, higher phosphate, and mixtures thereof.

6. A synthetic laundry detergent bar composition made by the process of Claim 1 , further comprising from about 0.1 0% to about 60% bleach agent.

7. A process for making a synthetic laundry detergent bar composition comprising the steps of: a. forming a mixture comprising a neutralized anionic synthetic detergent surfactant selected from the group consisting of C╬╣ o- i s linear alkyl benzene sulfonates, C I Q- 1 8 alkyl sulfates, and mixtures thereof; sodium tripolyphosphate detergency builder; optionally other ingredients; and from about 0.5% to about 10% aluminum salt, wherein substantially all of the phosphate detergency builder is added to the mixture after the aluminum salt; and b. forming into bars; wherein the bar composition comprises from about 1 5% to about 30% anionic synthetic detergent surfactant, by weight of the bar composition; and wherein the bar composition is substantially free of siliceous materials.

8. A process as claimed in Claim 7, wherein the aluminum salt is AI2 (SO₄)₃.

9. A synthetic laundry detergent bar composition made by the process of Claim 7, further comprising from about 1 % to about 1 0% amine oxide.

1 0. A synthetic laundry detergent bar composition made by the process of Claim 8, further comprising from about 1 % to about 50% bleach agent.