CN1117849C - Process for preparing granular detergent components - Google Patents

Abstract

The present invention relates to a process for the preparation of a particulate detergent composition or component having a bulk density greater than 650g/l, the process comprising the step of dispersing a liquid binder throughout a powder stream in a high speed mixer to form particulate agglomerates, wherein the powder stream contains crystalline zeolite a having an oil absorption capacity of at least 40ml/100g, preferably at least 45ml/100g, most preferably at least 50ml/100 g.

Description

Process for preparing granular detergent components

The present invention relates to a process for the continuous preparation of granular detergent compositions or components having high bulk density and good flow properties. In such compositions and components it is known to use as a builder a water-soluble crystalline material known in the detergent art, crystalline Zeolite A, which is especially suitable for removing cations such as calcium and magnesium from hard water.

Crystalline zeolite A is a very finely divided powder. One typically processes the finely divided powder into larger particle form (typically 400-1000 microns) before incorporation into the final product, especially the final detergent composition. Various granulation methods are known including spray drying and agglomeration. Conventional agglomeration processes in which zeolite A is used as one of the components are known in the prior art:

GB2005715 published 25 April 1979 describes an agglomeration process based on zeolite A. Zeolite A is agglomerated with carbonate/bicarbonate to form nonionic surfactant agglomerates.

WO 93/25378, published December 23, 1993, describes a process for the preparation of zeolite A-containing granular detergents. Zeolite A was agglomerated with high active, neutralized surfactant slurries in a high speed mixer and a medium speed mixer/agglomerator to produce anionic surfactant agglomerates.

One of the factors limiting the activity of the above-mentioned prior art surfactants is the capacity of zeolite A to absorb liquid organic substances. It has been suggested that the replacement of zeolite A by zeolite P (especially zeolite MAP) can solve this problem:

EP 521 635, published 7 January 1993, describes granular detergents prepared using 10% to 100% zeolite MAP. Zeolite MAP has a different chemical composition than Zeolite A. In Example 1 of this patent application, it is reported that the oil absorption capacity of zeolite MAP is 41.6 ml/100 g, which is higher than that of the measured samples of zeolite A, which is 26-35.5 ml/100 g.

However, modification of the chemical structure of conventional crystalline zeolite A (ie modifying the stoichiometric ratio of Si, Al, Na, O, H) is not always desirable since other properties and characteristics of the zeolite are necessarily affected.

It is an object of the present invention to provide a granulation process for the preparation of granular detergents which incorporates highly absorbent crystalline zeolites into granular agglomerates without losing their builder capacity, especially calcium exchange capacity and calcium exchange rate.

The object of the invention is achieved by the method disclosed in claim 1 using a modified crystalline zeolite A having a higher oil absorption capacity. To achieve an oil absorption capacity of at least 40 ml/100 g Zeolite A has a modified physical structure (ie crystallinity, surface area characteristics, moisture content, etc.) rather than a changed chemical structure. In this way, the excellent builder properties of zeolite A can still be utilized.

Another object of the present invention is to provide a granulation process for the preparation of granular detergents with improved processing stability and a reduced amount of oversized particles (or "clumps") formed during the process.

Summary of the invention

The objects of the present invention are achieved by a process for the preparation of granular detergent compositions or components having a bulk density greater than 650 g/l which comprises dispersing a liquid binder throughout a powder stream in a high speed mixer to form particle agglomerates A step in which the powder material comprises crystalline zeolite A having an oil absorption capacity of at least 40ml/100g, preferably at least 45ml/100g, most preferably at least 50ml/100g.

In a preferred embodiment of the invention, particle agglomerates are formed by mixing in a high speed mixer with a residence time of from about 2 seconds to about 30 seconds, followed by a mixture in a medium speed mixer/agglomerator for less than about 5 minutes. , preferably a moderate speed mixer residence time of less than about 2 minutes for a further mixing step where finely divided powders may optionally be added.

In various embodiments of the present invention, the liquid builder is a surfactant paste, an organic polymer or a silicone oil. The surfactant paste may contain anionic, nonionic, cationic, amphoteric, zwitterionic surfactants and mixtures thereof; of which anionic and/or nonionic surfactants are most preferred. Detailed description of the invention

Pelletization is defined in the present invention as a process for the preparation of granular products which are themselves particle agglomerates (according to S.A. Kuti, "Agglomeration - a practical option", published in Journal American Oil Chemists' Society, Vol. 55, 1978 January). Granular agglomerates are defined herein as the product of this granulation process. Kuti goes on to state that "agglomerates are often formed by mixing a solid and a liquid used as a binder, but it is often difficult to prepare a liquid-solid mixture without lumps".

What Kuti refers to as a "solid" in this invention will contain crystalline zeolite A having certain physical characteristics as detailed hereinafter. We have found that the choice of "solid" greatly facilitates the preparation of a lump-free liquid-solid mixture.

The main constituent of the granular agglomerates of the present invention is crystalline zeolite A of the formula:

(Na2O)·(Al2O3)·x(SiO2)·wH2O

where x is 1-2, and w is 0-6.

Hydrated or partially hydrated Natrolite A with a particle size of up to 10 microns is preferred.

In an especially preferred embodiment, x=2, Zeolite A has the formula:

Na ₁₂ [(AlO ₂ ) ₁₂ (SiO ₂ ) ₁₂ ]·(6w')H ₂ O

wherein (6w') is from about 20 to about 30, especially about 27, and has a particle size generally less than about 5 microns. The amount of crystalline zeolite A in the present invention is preferably from 20% to 70% by weight of the granular detergent.

The zeolite A materials of the present invention contain up to 28% water. Preferred builder materials are in hydrated form, containing from about 5% to about 28% by weight water. More preferred crystalline aluminum silicate ion exchange materials contain from about 10% to about 22% water in their crystalline matrix. The crystalline zeolite A material is further characterized by a particle size diameter of from about 0.1 to about 10 microns. Preferred ion exchange materials have a particle size diameter of from about 0.2 microns to about 4 microns. The term "particle size diameter" in the present invention means the average particle size diameter by weight of a given ion exchange material, as determined by conventional analytical techniques such as microscopic methods using electron scanning anchor microscopy. The crystalline zeolite A materials of the present invention are further characterized by a calcium ion exchange capacity on a dry basis of at least about 200 mg equivalent calcium carbonate water hardness/g aluminum silicate, typically about 300 mg equivalent/g to 352 mg equivalent/g. The zeolite A materials of the present invention are further characterized in that, based on calcium ion hardness, they have a calcium ion exchange rate of at least about 2 grains Ca ⁺⁺ /gallon/minute/gram/gallon (0.13 g ^Ca++ /liter/minute/gram /l) aluminum silicate (dry basis), typically 2 grains Ca ⁺⁺ /gal/min/g/gal (0.13gCa ⁺⁺ /l/min/g/l) to 6 grains Ca ⁺⁺ /gal /min/g/gal (0.39gCa ⁺⁺ /l/min/g/l). Optimum aluminum silicates for builders exhibit calcium ion exchange rates of at least 4 gCa ⁺⁺ /gallon/minute/gram/gallon (0.26 gCa ⁺⁺ /liter/minute/gram/liter).

Zeolite A for use in the present invention is commercially available. Examples of suitable zeolite A materials are Soprolit (manufacturer ref. 94/099/1) and Enichem (manufacturer ref. AF1094). The aluminum silicates used in the present invention are crystalline in structure and may be naturally occurring aluminum silicates or synthetically derived. Methods for preparing aluminosilicate ion exchange materials are discussed in US Patent 3,985,669, Krummel et al., issued October 12, 1976, which is incorporated herein by reference.

An essential feature of the present invention is that the zeolite A used to form the particle agglomerate has an oil absorption capacity of at least 40ml/100g, preferably at least 45ml/100g, most preferably at least 50ml/100g. The method for determining the oil absorption capacity is described in "Test Method" hereinafter.

Other forms of zeolite may optionally be mixed with zeolite A, such as zeolite P, zeolite X and zeolite HS.

The granular agglomerates of the present invention may also contain other detergent ingredients.

Water-soluble salts of higher fatty acids, ie "soaps" are useful anionic surfactants in the compositions of the present invention. These include alkali metal soaps such as the sodium, potassium, ammonium and alkylammonium salts of higher fatty acids containing from about 8 to about 24 carbon atoms, preferably from about 12 to about 18 carbon atoms. Soaps can be prepared by direct saponification of fats and oils or by neutralization of free fatty acids. Particularly useful are the sodium and potassium salts of fatty acid mixtures derived from coconut oil and tallow, ie sodium or potassium tallow and coconut soaps. Neutralized anionic surfactants are preferred.

Useful anionic surfactants also include water-soluble salts, preferably alkali metal, ammonium, and alkane salts of organosulfated reaction products containing from about 10 to about 20 carbon atoms in their molecular structure and sulfonic acid or sulfate groups. Alcohol ammonium salt. (Included in the term "alkyl" are the alkyl moieties of acyl groups). Examples of synthetic surfactants of this group are sodium and potassium alkyl sulphates, obtained especially by sulphating higher fatty alcohols ( _C8 - _C18 carbon atoms), e.g. alcohols obtained by reduction of glycerides of animal or coconut oils, Products; sodium and potassium alkylbenzene sulfonates, wherein the alkyl group contains from about 9 to about 15 carbon atoms, in a linear or branched configuration, such as those described in US 2,220,099 and 2,477,383; and methyl sulfonate. Of particular value are linear alkylbenzene sulfonates wherein the average number of carbon atoms in the alkyl group is about 11-13, abbreviated _C11 - _C13 LAS.

Other anionic surfactants of the present invention are sodium alkyl glyceryl ether sulfonates, especially ethers of higher alcohols obtained from animal and coconut oils; sodium coconut oil fatty acid monoglyceride sulfonates and sodium sulfate; each molecule contains from about 1 to about Alkylphenol oxirane ether sulfate sodium or potassium salts of 10 ethylene oxide units, wherein the alkyl group contains from about 8 to about 12 carbon atoms; and contains from about 1 to about 10 ethylene oxide units per molecule Alkyl oxirane ether sulfate sodium or potassium salts wherein the alkyl group contains from about 10 to about 20 carbon atoms.

Other useful anionic surfactants of the present invention include the water-soluble salts of alpha-sulfonated fatty acid esters containing about 6 to 20 carbon atoms in the fatty acid group and about 1 to 10 carbon atoms in the ester group; Water-soluble salts of 2-acyloxy-alkane-1-sulfonic acids containing about 2 to 9 carbon atoms in the acyl portion and about 9 to about 23 carbon atoms in the alkane portion; about 10 to 20 in the alkyl portion Alkyl ether sulfates having 3 carbon atoms and about 1 to about 30 moles of ethylene oxide; water-soluble salts of olefin sulfonates containing about 12 to 24 carbon atoms; and containing about 1 to 3 carbons in the alkyl moiety atoms and beta-alkoxyalkane sulfonates containing from about 8 to about 20 carbon atoms in the alkane moiety. Although acid salts are commonly discussed and used, neutralization of the acid may be performed as part of the finely dispersed mixing step.

Water-soluble nonionic surfactants can also be used as surfactants in the compositions of the present invention. In fact, preferred methods use anionic/nonionic mixtures. The nonionic materials include compounds prepared by condensation of alkylene oxide groups (hydrophilic) with organic hydrophobic compounds that are aliphatic or alkylaromatic in nature. The length of the polyoxyalkylene group condensed with any particular hydrophobic group can be readily adjusted to obtain a water-soluble compound having the desired balance of hydrophilic and hydrophobic moieties.

Suitable nonionic surfactants include polyethylene oxide condensates of alkylphenols, such as alkylphenols having an alkyl group of about 6 to 16 carbon atoms in a linear or branched configuration per mole of alkyl Phenol is a condensation product of about 4-25 moles of ethylene oxide.

Preferred nonionic surfactants are aliphatic alcohols in linear or branched configurations containing 8-22 carbon atoms with 1-25 moles of ethylene oxide per mole of alcohol, especially 2-7 moles of cyclic alcohol per mole of alcohol Water-soluble condensation product of ethylene oxide. Especially preferred are the condensation products of alcohols having an alkyl group containing about 9 to 15 carbon atoms; and the condensation products of propylene glycol and ethylene oxide.

Other preferred nonionic surfactants are polyhydroxy fatty acid amides prepared by reacting fatty acid esters with N-alkyl polyhydroxy amines. A preferred amine for use in the present invention is N-(R1)CH2(CH2OH)4-CH2-OH and a preferred ester is C12-C20 fatty acid methyl ester. Most preferred are the condensation products of N-methylglucamine (which is derived from glucose) and C12-C20 fatty acid methyl esters.

A process for the preparation of polyhydroxy fatty acid amides is described in WO9206073, published April 16,1992. This application describes a process for the preparation of polyhydroxy fatty acid amides in the presence of solvents. In a more preferred embodiment of the invention, N-methylglucamine is reacted with a C12-C20 methyl ester. It also states that formulators of granular detergent compositions will find it easy to carry out the amidation reaction in the presence of alkoxylated, especially ethoxylated (EO 3-8 ) C12-C14 alcohols (p. 15 , lines 22-27). This leads directly to nonionic surfactant systems suitable for use in the present invention, for example C12-C14 alcohols which contain N-methylglucamide and 3 ethoxylated groups per molecule.

Semi-polar nonionic surfactants include water-soluble amine oxides containing an alkyl group of about 10 to 18 carbon atoms and two groups selected from alkyl and hydroxyalkyl groups of 1 to about 3 carbon atoms; Water-soluble phosphine oxides containing an alkyl group of about 10-18 carbon atoms and two groups selected from alkyl and hydroxyalkyl groups containing 1-about 3 carbon atoms; and containing a group of about 10-18 carbon atoms Alkyl atoms and a water-soluble sulfoxide group selected from alkyl and hydroxyalkyl groups containing 1 to about 3 carbon atoms.

Amphoteric surfactants include aliphatic derivatives or aliphatic derivatives of heterocyclic secondary and tertiary amines, wherein the aliphatic group may be linear or branched, and wherein one of the aliphatic substituents contains about 8-18 carbon atoms, and at least one aliphatic substituent containing anionic water solubilizing groups.

Zwitterionic surfactants include derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounds wherein one of the aliphatic substituents contains about 8-18 carbon atoms.

Useful cationic surfactants include water-soluble quaternary ammonium compounds of the formula R ₄ R ₅ R ₆ R ₇ N ^{+ X-} , wherein R ₄ is an alkyl group of 10-20, preferably 12-18 carbon atoms, R ₅ , R ₆ and R ₇ are C ₁ -C ₇ alkyl, preferably methyl; X- is an anion, such as chloride ion. Examples of the trimethylammonium compound include C _12-14 alkyltrimethylammonium chloride and coconut alkyltrimethylammonium N-methylsulfate.

The granular detergents of the present invention may contain neutral or basic salts which in aqueous solution have a pH of 7 or greater and which may be inorganic or organic in nature. Builder salts help to provide the desired bulk density to the detergent granules of the present invention. Although some salts are inert, many salts also function as detergency builder materials in laundry solutions.

Examples of neutral aqueous salts include the alkali metal, ammonium or substituted ammonium chlorides, fluorides and sulfates. The abovementioned alkali metal salts, especially sodium salts, are preferred. Sodium sulfate is commonly used in detergent granules and is an especially preferred salt, citric acid, and generally any other organic or inorganic acid may be added to the granular detergents of the present invention as long as it is chemically compatible with the other components of the agglomerated composition. Allow.

Other useful aqueous salts include compounds of commonly known detergent builder materials. Builders are generally selected from the various water-soluble alkali metal, ammonium or substituted ammonium phosphates, polyphosphates, phosphonates, polyphosphonates, carbonates, silicates, borates and polyhydroxy Sulfonate. Preference is given to the abovementioned alkali metal salts, especially the sodium salts.

Specific examples of inorganic phosphate builders are the sodium and potassium tripolyphosphates, pyrophosphates, polymeric metaphosphates having a degree of polymerization of about 6-21, and orthophosphates. Examples of polyphosphate builders are the sodium and potassium salts of ethylene diphosphonate, ethane, the sodium and potassium salts of 1-hydroxy-1,1-diphosphonic acid and ethane, 1,1,2-triphosphonic acid sodium and potassium salts. Other phosphorus builder compounds are disclosed in US3159581; US3213030; US3422021; US3422137; US3400176; US3400148, incorporated herein by reference.

Examples of non-phosphorous inorganic builders are carbonates, bicarbonates, sesquicarbonates, tetraborate decahydrate and silica to alkali metal oxide molar ratios of from about 0.5 to about 4.0, preferably about Sodium and potassium silicates from 1.0 to about 2.4. To operate, compositions prepared by the process of the present invention do not require excess carbonate, and preferably do not require more than 2% finely divided calcium carbonate as described in US4196093, Clarke et al., issued April 1, 1980, and The latter is preferably absent.

Also useful are various organic polymers, some of which can also be used as builders to improve detergency. The polymers include sodium carboxy-lower alkylcellulose, sodium lower alkylcellulose and sodium hydroxylower alkylcellulose, for example, sodium carboxymethylcellulose, sodium methylcellulose and sodium hydroxypropylcellulose, Polyvinyl alcohol (which often also contains some polyvinyl acetate), polyacrylamides, polyacrylates, and various copolymers, such as copolymers of maleic and acrylic acid. The molecular weight of these polymers can vary widely, but most are in the range of 2,000-100,000. Other suitable polymers are polyamine N-oxide polymers, copolymers of N-vinylimidrolidone and N-vinylimidazole, polyvinylpyrrolidone polymers, polyvinyloxazolidone and polyvinyl imidazole or their mixtures.

Polymeric polycarboxylate builders are described in US Patent 3,308,067, Diehl, issued March 7,1967. Such materials include the water-soluble salts of aliphatic carboxylic acids such as homo- and copolymers of maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, citraconic acid and methylenemalonic acid.

silicone oil

Granular suds suppressors can also be added directly to the agglomerates of the present invention by feeding the powder stream into the agglomeration unit or added to the final composition by dry addition. The suds suppressing activity of these particles is preferably based on fatty acids or silicones.

In one embodiment of the invention, silicone oil (preferably at least 30% by weight of silicone oil) is absorbed on a special zeolite A.

optional components

Other ingredients commonly used in detergent compositions may be included in the compositions of the present invention. These include flow aids, stains, bleaches and bleach activators, foaming or suds suppressors, antitarnish and preservatives, soil suspending agents, soil release agents, dyes, fillers, optical brighteners, bactericides , pH adjusters, non-builder alkali sources, solubilizers, enzymes, enzyme stabilizers, chelating agents and fragrances.

These optional components, especially optical brighteners, can be added directly to the agglomerates of the present invention or can be added to the components of the agglomerates of the present invention as components of individual particles suitable for dry addition.

processing

Useful agglomeration methods are disclosed in EP-A-510746, published October 28, 1992, and WO 93/25378, published December 23, 1993. These applications describe the agglomeration of solids with high active neutralizing surfactant slurries. However, it can be understood that the highly active neutralizing slurry can be completely or partially replaced by other surfactants, especially nonionic surfactants (such as EP643130 disclosed on March 15, 1995), or by organic polymers or silicone oils . Preferred embodiments of the present invention are described in detail in the following examples.

Test Methods

The oil absorption value can be determined by the following British Standards, BS3483: part7: 1982 (corresponding to ISO 787/5-1980). A 5 g sample of zeolite A containing less than 0.5% free base was used. The oil absorption value (OAV) is represented by the following formula:

Example

All values are expressed in % by weight. Zeolite content is on a hydrated basis including 15% by weight bound water.

Example 1 Example 2 Example 3 Comparative Example A

Zeolite A ^* 32 22 52 -

Zeolite A# - - - - - - 32

C12-15AS 24 31 - 24C12-15AE3S 6 8 8 - 6

Sodium Carbonate 25 12 13 25

Copolymer - 12 - -Nonionic Surfactant - - - 30 -

Water 5 5 5 - 5

Minor component 8 10 5 8

Zeolite A ^* was supplied by Industrial Zeolites (UK) Ltd. of Thurrock, Essex, England, oil absorption capacity 45.5ml/100g.

Zeolite A# is available from Degussa under the tradename Wessalith(R) and has an oil absorption capacity of 36ml/100g.

C12-15AS is sodium alkyl sulfate, and the alkyl chain mainly contains C12-C15.

C12-15AE3S is sodium alkyl ether sulfate, the alkyl chain mainly contains C12-C15, and an average of 3 ethoxy groups per molecule.

Copolymer is a copolymer of acrylic acid and maleic acid.

The nonionic surfactant contains 7 parts of ethoxylated alcohol, wherein the alkyl chain mainly contains C12-C15, and an average of 3 ethoxy groups per molecule, and 3 parts of C12-14 polyhydroxy fatty acid amide.

Minor components are mainly sulfates and some other minor impurities.

Agglomerates of particles containing the components of Example 1 were prepared by the following method. The powdered ingredients (zeolite A and sodium carbonate) were added to the pot of an Eirich(R) mixer rotating at 64 rpm and mixed for 10 seconds. The mixer pot was then stopped and a preheated surfactant slurry (50°C), 80% surfactant active ingredient in aqueous solution, was added in the form of tablets to the void formed in the middle of the powder. The removed loose powder is placed on the slurry to completely cover it. The mixer was then re-spun, the pot was rotated at 64rpm and the chopper was set at 2500rpm. Mixing was stopped when particle agglomerates began to form (at this point the current controlled by Eirich was raised from 2.8 to 3 amps).

The resulting particle agglomerates are free flowing and contain less than 25% by weight of oversize particles (oversize particles are considered particles having a particle size greater than 1600 microns).

Agglomerates of particles containing the components of Example 2 were prepared by the following method.

A surfactant-containing slurry was prepared by sulfation and neutralization of the appropriate alcohol, resulting in a slurry with a moisture content of 18%. The slurry was pumped into a high shear mixer (Loedige CB®), and Zeolite A and sodium carbonate were added to the high shear mixer to mix thoroughly with the high viscosity slurry therein. The resulting mixture was transferred directly to a low shear mixer (Loedige KM®) to form agglomerates. After exiting the low shear mixer, the agglomerates were sieved to remove oversize "lumps" and fines. Finally the agglomerates are cooled in a fluidized bed and stored before being dry blended with other detergent powders to make the final product. The residence time in the high shear mixer was about 8 seconds and the residence time in the low shear mixer was about 35 seconds.

Agglomerates of particles containing the composition of Example 3 were prepared by the same method as in Example 2, the anionic surfactant slurry being replaced by nonionic surfactant maintained at 70°C as a viscous slurry.

Agglomerates of particles containing the components of Comparative Example A were prepared by the same method as in Example 1, using the same mixing time of powder and slurry as described in Example 1. The resulting particle agglomerates contain greater than 25% by weight of oversize particles (oversize particles are considered particles having a particle size greater than 1600 microns).

Claims (9)

1. A process for the preparation of granular detergent components having a bulk density greater than 650 g/l, the process comprising the step of dispersing a liquid binder throughout a powder stream in a high speed mixer to form granular agglomerates, wherein the powder stream There is crystalline zeolite A having an oil absorption capacity of at least 40ml/100g, and the granular detergent component comprises crystalline zeolite A and at least 30% by weight of silicone oil. 2. The method of claim 1, wherein said granular detergent component comprises: (a) 20% to 70% by weight of crystalline zeolite A having an oil absorption capacity of at least 40ml/100g; and (b) At least 30% by weight of silicone oil. 3. The method of claim 1, wherein the step of forming the particle agglomerate is as follows: Mixing in a high-speed mixer with a residence time of 2 seconds to 30 seconds; Further mixing is then carried out in a moderate speed mixer/agglomerator with a residence time of less than 5 minutes through the moderate speed mixer, optionally with the addition of finely divided powder. 4. The method of claim 3, wherein the residence time through the moderate speed mixer is less than 2 minutes. 5. The method of claim 1 wherein said granular detergent component further comprises a neutralized anionic surfactant. 6. The method of claim 1 wherein said granular detergent component further comprises a surfactant selected from the group consisting of anionic, nonionic, cationic, amphoteric, zwitterionic surfactants and mixtures thereof. 7. The method of claim 2 wherein said granular detergent component further comprises a surfactant selected from the group consisting of anionic, nonionic, cationic, amphoteric, zwitterionic surfactants and mixtures thereof. 8. The method of claim 1, wherein said crystalline zeolite A has an oil absorption capacity of at least 45 ml/100 g. 9. The method of claim 1, wherein said crystalline zeolite A has an oil absorption capacity of at least 50 ml/100 g.