FI90786B - Liquid detergent composition containing perborate bleach - Google Patents

Description

90786

This invention relates to aqueous liquid detergent compositions containing perborate bleach in the form of small particles, i.e., particles having a weight average particle diameter of 0.5 to 20 μm. The small particles are formed by recrystallization in situ, preferably perborate monohydrate.

Currently commercially available liquid so-called high power detergent compositions typically do not contain bleach. Dissolved peroxygen compounds, such as hydrogen peroxide, interact with other components commonly used in liquid detergents, such as enzymes and perfumes.

The problem with insoluble peroxygen bleach compounds is the poor physical stability of the suspensions prepared therefrom.

DE-A-3,511,515 describes anhydrous liquid detergent compositions containing sodium perborate monohydrate and a perborate activator. FR 2,579,615 describes similar anhydrous compositions which additionally contain catalase inhibitors. The compositions exemplified in these two patents do not contain anionic surfactants.

J. Dugua and B. Simon [Crystallization of Sodium Perborate from Aqueous Solutions, Journal of Crystal Growth, 44 (1978) 265-286] discuss the effect of surfactants on sodium perborate tetrahydrate nucleation and crystal growth.

It is an object of the present invention to provide aqueous liquid detergent compositions containing perborate particles having a weight average particle diameter of 0.5 to 20. It is a further object of the invention to provide a process for preparing said liquid detergent compositions, wherein particles of the desired particle size are formed in situ.

The aqueous liquid detergent compositions of this invention have a pH of at least 8 and are characterized in that they contain at least 5% organic anionic surfactant other than soap, at least 5% builder (surfactant) and 1 to 40%, preferably 10 to 20% of perborate bleach as particles having a mass average particle diameter of 0.5 to 20 and formed by in situ recrystallization.

The perborate particles are preferably formed by recrystallization in situ of perborate monohydrate, for example sodium perborate monohydrate.

Preferred liquid detergent compositions further comprise from 5 to 70% water-miscible organic solvent. Preferred water-miscible organic solvents are low molecular weight monohydric alcohols; the most preferred of these solvents is ethanol.

In the context of the invention, detergent compositions having a pH of at least 9, more preferably at least 9.5, are preferred.

The present invention addresses the problem of formulating an aqueous liquid detergent composition containing suspended small perborate bleach particles. From the point of view of physical stability, it is necessary that the mass average particle diameter of the perborate particles is 0.5 to 20 μm. It does not make sense to make such small particles by grinding, for example, because said method is not particularly economically attractive. In addition, such small particles would cause serious industrial hygiene and safety problems in the dry state.

It has also been found that detergent compositions containing small perborate particles prepared by grinding are less physically stable than compositions containing by diameter

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90786 3 similar perborate particles obtained by in situ crystallization. Although this phenomenon is not fully understood, it is assumed that the shape of the particle is relevant in this context.

It has now been found that the required small perborate particles can be formed by in situ recrystallization in the presence of at least 5% organic anionic non-soap surfactant and at least 5% detergent builder.

10 The percentages used herein are by weight of the liquid detergent composition. The weight percentages of perborate are calculated as perborate monohydrate, although the particles may be of different compositions (e.g. tetrahydrate).

The term "in situ recrystallization" refers to processes in which perborate particles are formed from larger particles in the presence of a matrix of water, an anionic surfactant, and a detergent Builder. This term thus encompasses processes involving chemical reactions, such as the formation of sodium perborate by reacting stoichiometric amounts of hydrogen peroxide and sodium metaborate. Also included are methods involving dissolution and recrystallization, such as dissolving perborate monohydrate and then forming perborate tetrahydrate. Recrystallization can also occur by allowing the perborate monohydrate to take up water of crystallization, whereby the monohydrate recrystallizes directly as a tetraborate without a dissolution step.

In one embodiment of the invention, a perborate compound, for example sodium perborate tetrahydrate or sodium perborate monohydrate, is added to an aqueous mixture containing an anionic surfactant and a detergent builder. The resulting slurry is mixed.

During this mixing, the perborate compound dissolves and recrystallizes. Due to the presence of anionic surfactant and detergent Builder, this dissolution-recrystallization process results in particles with the desired particle diameter.

Because the monohydrate recrystallizes more easily, the monohydrate is preferred for this embodiment of the invention. Particle diameters used herein are mass-average particle diameters unless otherwise indicated. From the point of view of physical stability, it is preferred that the particle size distribution is relatively narrow, i.e. it is preferred that less than 10% of the perborate is in the form of particles having a diameter of more than 25 pn, and more preferably less than 10% by weight of the particles have a diameter of more than 10. um.

In another embodiment of the invention, the perborate compounds are formed in situ by a chemical reaction. For example, sodium metaborate is added to an aqueous liquid containing an anionic surfactant and a detergent builder. A stoichiometric amount of hydrogen peroxide is added with stirring. Stirring is continued until the chemical reaction has gone to lop-20 wood.

Instead of metaborate, other borate compounds can be used, including, for example, borax and boric acid. If borax is used as the boron compound, a stoichiometric amount of base, for example sodium hydroxide, is added to ensure that the borax reacts to become a metabolite. The process then proceeds as described above in connection with the modification of the metabolite. Instead of hydrogen peroxide, other peroxides (for example sodium peroxide) can be used, as is known in the art.

Perborate tetrahydrate is normally formed.

At temperatures above about 40 ° C, this may slowly change to a more thermodynamically stable trihydrate. This transformation per se can be used to prepare small trihydrate particles from large tetrahydrate particles.

li 90786 5

Preferred liquid detergent compositions contain, in addition to water, a water-miscible organic solvent. The solvent reduces the solubility of the perborate in the liquid phase and thus improves the chemical stability of the composition.

The organic solvent need not be completely miscible with water, provided that the water in the composition is miscible with the solvent to the extent that it affects the solubility of the perborate compound in the liquid phase.

The water-miscible solvent must, of course, be compatible with the perborate compound at the pH used. Therefore, polyalcohols having vicinal hydroxyl groups (e.g., 1,2-propanediol and Gly-15 serol) are less preferred.

Examples of suitable water-miscible organic solvents are lower aliphatic monoalcohols and ethers of diethylene glycol and lower monoaliphatic monoalcohols. Preferred solvents are ethanol, isopropanol, 1-methoxy-2-propanol and butyl diglycol ether.

Although the presence or absence of other ingredients is important, the amount of oxygen available in solution is largely determined by the ratio of water to organic solvent. The lower this ratio (i.e., the more organic solvent used in the solvent system), the lower the amount of available oxygen in the class. While this is good for the stability of the bleaching system, it is less desirable for the good solubility of other components (e.g., electrolyte and anionic surfactants).

In practice, the ratio of water to organic solvent is in the range of 8: 1 to 1: 3, preferably 5: 1 to 1: 2. When calculating the amount of water in a detergent composition, account should be taken of water released or bound by chemical and physical events 6 that may occur during the preparation of the detergent composition. For example, water may be formed upon neutralization of the anionic surfactant, whereas water may be bound when the metaborate is converted to perborate tetrahydrate as well as when perborate-5-timonohydrate is converted to perborate tetrahydrate. Water is also present in most detergent raw materials and should be considered.

Since it is assumed that the ionic strength of the composition affects the dissolution-recrystallization process, the ionic strength of the compositions is preferably at least 0.8 mol / l, preferably 2 to 3.5 mol / l. The ionic strengths are calculated assuming that all materials present in the composition except perborate are completely dissociated.

The liquid detergent compositions of the invention contain 5 to 60%, preferably 15 to 40% of the liquid detergent composition of an organic surfactant which is a nonionic, anionic or zwitterionic surfactant or a mixture thereof. The detergent composition should contain at least 5% anionic surfactant.

Synthetic anionic surfactants can be represented by the general formula R 2 SO 2 M having a hydrocarbon group which is a straight-chain or branched alkyl group containing about 8 to 24 carbon atoms, or an alkylphenyl group having an alkyl group containing about 9 to 15 carbon atoms. M is a salt-forming cation, which is typically sodium, potassium or ammonium ions or a mixture thereof.

A preferred synthetic anionic surfactant is a water-soluble alkylbenzenesulfonic acid having an alkyl group of 9 to 15 carbon atoms. Another preferred synthetic anionic surfactant is a water-soluble salt of an alkyl sulfate or alkyl polyethoxy 35-sulphate ether sulfate having an alkyl group of about 8 to 24, preferably about 10 to about 90786 7 18 carbon atoms and having 0 to about 20, preferably 0 to about 12 ethoxyl groups. . Other suitable anionic surfactants are disclosed in U.S. Patent 4,170,565.

Nonionic surfactants are conveniently prepared by condensing ethylene oxide with a hydrocarbon having a reactive hydrogen atom, for example a hydroxyl, carboxyl or amide group, in the presence of an acid or base catalyst, and include compounds of general formula RA ( CH 2 CH 2 O) H, where R is a hydrophobic group, A is a group containing a reactive hydrogen atom, and n is the average number of ethylene oxide units.

R typically contains about 8 to 22 carbon atoms. They can also be formed by condensing propylene oxide with a lower molecular weight compound, n is generally 2-24.

The hydrophobic group of the nonionic compound is preferably a primary or secondary and straight-chain or branched aliphatic alcohol having 8 to 24, preferably about 12 to 20 carbon atoms. Suitable nonionic surfactants are more fully described in U.S. Patent 4,111,855. Mixtures of nonionic surfactants may be preferred.

Dual anionic surfactants include derivatives of aliphatic quaternary ammonium, phosphonium and sulfonium compounds in which the aliphatic group may be straight-chain or branched and in which one aliphatic substituent contains about 8 to 24 carbon atoms and one of the substituents is always an aqueous quinone anion. group. Particularly preferred zwitterions are the ethoxylated ammonium sulfonates and sulfates described in U.S. Patent Nos. 3,925,262 and 3,929,678.

Semi-polar nonionic surfactants include water-soluble amine oxides containing one alkyl or hydroxyalkyl group having about 8 to 28 carbon atoms and two groups having alkyl groups or hydroxyalkyl groups containing 1 to 3 carbon atoms and may optionally be attached in a ring structure. .

Suitable anionic synthetic surfactant salts include sulfonates and sulfates. Such anionic detergents are well known in the detergent art and are widely used in commercial detergents. Preferred anionic synthetic water-soluble sulfonate or sulfate salts contain an alkyl group containing about 8 to 22 carbon atoms in their molecular structure.

Examples of such preferred anionic surfactant salts are reaction products obtained by sulfating Cg-Ig fatty alcohols derived from tallow and coconut oil; alkylbenzenesulfonates in which the alkyl group contains about 9 to 15 carbon atoms; natriumalkyyliglyseryylieetterisulfonaatit; ether sulphates of fatty alcohols derived from tallow and coconut oil; Coconut fatty acid monoglyceride sulfates and sulfonates; and water-soluble salts of paraffin sulfonates having an alkyl chain of about 8 to 22 carbon atoms. Sulfonated olefin-based surfactants, which are described in more detail in, for example, U.S. Patent No. 3,332,880, may also be used. Neutralizing cations of anionic synthetic sulfonates and / or sulfates are represented by conventional cations widely used in detergent technology, such as sodium and potassium.

A particularly preferred anionic synthetic surfactant component in the context of this invention is a water-soluble salt of alkylbenzenesulfonic acid, preferably sodium alkylbenzenesulfonic acid, preferably sodium alkylbenzenesulfonate having an alkyl group containing about 10 to 13 carbon atoms.

A preferred group of nonionic ethoxylates are the condensation products of fatty alcohols 90786 9 having 12 to 15 carbon atoms with ethylene oxide of about 4 to 10 moles per mole of fatty alcohol. Suitable representatives of this ethoxylate group include the condensation product of C 12 -C 10 oxoalcohols and ethylene oxide of 7 to 9 moles per mole of alcohol; a condensation product of narrow molecular size C 1-4 oxoalcohols and ethylene oxide of 7-9 moles per mole of fatty oxoalcohol; a condensation product of a C2-23 fatty alcohol having a narrow molecular size range and ethylene oxide of 6.5 moles per mole of fatty alcohol; and C. Λ ..- coconut fatty alcohol condensation products having a degree of ethoxylation (molar amount of EO / 1 mol of alcohol) in the range of 5-8. Although fatty oxoalcohols are predominantly linear, they may exhibit some degree of branching, especially short side chains such as methyl branches, depending on the processing conditions and the feedstock olefins.

The degree of branching of commercial oxoalcohols is often in the range of 15 to 50% (w / w).

The preferred nonionic ethoxylated component may also be a mixture of two separately ethoxylated nonionic surfactants having different degrees of ethoxylation. Examples include a nonionic ethoxylated surfactant containing 3 to 7 moles of ethylene oxide / 1 mole of hydrophobic groups, and another ethoxylated agent having 8 to 14 moles of ethylene oxide / 1 mole of hydrophobic groups. A preferred nonionic ethoxylated mixture contains a lower ethoxylate which is the condensation product of a C 1-4 oxo alcohol having a degree of branching of up to 50% by weight and ethylene oxide of about 3-7 mol / l mol fatty oxoalcohol, and a higher ethoxylate. , which is the product of the condensation of C 1-4 oxoalcohol having a degree of branching of more than 50% by mass and ethylene oxide having about 8-14 mol / l mol of branched oxoalcohol.

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The liquid detergent compositions of the invention optionally contain a fatty acid component. Preferably saturated fatty acids contain 10 to 16, more preferably 12 to 14 carbon atoms. Preferred unsaturated fatty acids are oleic acid and palmitoleic acid.

Detergent enzymes can be used in the liquid detergent compositions of this invention. In fact, a preferred feature of the compositions of the invention is that they are compatible with such detergent enzymes. Suitable enzymes include proteases, amylases, lipases and cellulases for use in detergents. Enzyme stabilizers for use in aqueous liquid detergents are well known. In this connection, a salt of formic acid, for example sodium formate, is preferred. The amount of this stabilizer is typically 0.5 to 2%.

Preferred compositions contain an inorganic or organic builder. Examples of inorganic builders are phosphorus-based builders, for example sodium tripolyphosphate and sodium pyrophosphate, and aluminosilicates (zeolites).

Examples of organic builders include poly acids such as citric acid, nitrile triacetic acid, and mixtures of tartrate monosuccinate and tartrate disuccinate. Preferred builders for use in the present invention are citric acid and alk (en) yl-substituted succinic acid compounds in which the alk (en) yl group contains from 10 to 16 carbon atoms. One example of this group is dodecenyl succinic acid. Polymeric carboxylate builders, including polyacrylates, polyhydroxyacrylates, and polyacrylate-polypolylate copolymers, can also be used.

The compositions of the invention may contain a number of other possible ingredients which are used mainly in additive concentrations, usually less than 5%. Examples of such additives are polyacids, enzymes and enzyme stabilizers of about 90786 11, foaming agents, opacifiers, substances which improve compatibility with enamelled surfaces of the machine, bactericides, dyes, perfumes, brighteners and the like.

The liquid compositions of the invention may contain other additives in concentrations of 0.05 to 2%.

These additives include polyaminocarboxylates such as ethylenediaminotetraacetic acid, diethylenetriaminopentaacetic acid, ethylenediaminodimeric acid or their water-soluble alkali metal salts.

Other additives include organophosphonic acids, of which ethylenediaminotetramethylenephosphonic acid, hexamethylenediaminotetramethylenephosphonic acid, diethylenetriaminopentamethylenephosphonic acid and aminomethylenediphosphonic acid are particularly preferred.

The compositions may further contain bleach stabilizers of a species known in the art.

If a process using hydrogen peroxide is used in the preparation of a liquid detergent, typical bleach stabilizers may be present when imported with commercially available hydrogen peroxide. Examples of suitable bleach stabilizers are ascorbic acid, dipicolinic acid, sodium stannates and 8-hydroxy-25-quinoline, and may be present in the compositions of the invention in concentrations of 0.01-1%.

Successful use of the compositions of the invention under a variety of conditions of use may require the use of a suds control agent. Although generally all detergent foaming agents can be used, alkylated polysiloxanes, such as dimethylpolysiloxane, often referred to as silicones, are preferred in the context of the invention. Silicones are often used in concentrations not exceeding 1.5%, most preferably in concentrations of 0.1 to 1.0%.

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It may also be advantageous to use as opacity enhancers as they help to make the concentrated liquid detergent composition uniform in appearance. An example of a suitable opacifier is poly-5 styrene sold under the tradename LYTRON 621 and manufactured by MONSANTO CHEMICAL CORPORATION. Opacity regulators are often used at concentrations of 0.3 to 1.5%.

The liquid detergent compositions of this invention may further contain an agent that improves compatibility with the washing machine, especially with respect to enamel coated surfaces.

In addition, it may be desirable to add 0.1 to 5% of known antifouling and / or compatibility enhancers. Examples of such additives are sodium carboxymethylcellulose; hyd-hydroxy-C ^ _G-alkylcellulose; polycarboxylic homo- and copolymer components such as polymaleic acid, a copolymer of maleic anhydride and methyl vinyl ether in a molar ratio of 2: 1 to 1: 2; and a copolymer of an ethylenically unsaturated monocarboxylic acid monomer having up to 5, preferably 3 or 4 carbon atoms, for example (meth) acrylic acid, and an ethylenically unsaturated dicarboxylic acid monomer having up to 6, preferably 4 carbon atoms, in which 1 molar ratio of monomers: 4: 1 and described in more detail in EP-A-0 066 915.

The following examples illustrate the invention and facilitate its understanding.

Liquid detergent compositions are prepared by mixing the following ingredients in the indicated proportions: il 90786 13

Ingredients Composition (pulp-JO

_I_II_III_IV_V

Water 33 32 26 23 34

Ethanol 14 15 18 22 11 5 Linear dodecylbenzenesulphonic acid 12 10 8 8 12 Condensation product of C 1-4 oxoalcohol (1 mol) and ethylene oxide (7 mol) 7 9 10 87 10 Sodium cocoyl sulphate 2 34 22

Dodecenyl succinic acid

Citric acid 0.8 1 1 0.8 0.8 Oleic acid 3.3 4 3 2 3.3

Protease 0.3 0.5 - 0.5 - 15 Diethylenetriamine-pentamethylenephosphonic acid 0.05 0.85 0.05 0.05 0.05

Sodium formate 0.9 1 - 1

Sodium perborate *) 20 monohydrate 10 10 12 10 10

Sodium hydroxide, to adjust the pH to 9 10 9 11 8.2

Perfume, other substances -------------- balance ------------- 25 *) sodium perborate tetrahydrate

The sodium perborate compound is added after all the other ingredients have been mixed. The composition is stirred overnight. The resulting recrystallized perborate particles have a weight average particle diameter of about 7 microns.

The following compositions are prepared in the same manner.

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Ingredients Kccstunus Inassa--.) Vi vii viii ix xi:

Water 28 27 32 28 22 31 23

Ethanol - 7 5 7 86,36 5 1-methoxy-2-propanol 14 3,5 - 7 7 -

Isoprcpanolia - - - - - 6.56

Butyl diglycol ether - 4,0 5-linear dode-10 alkylbenzenesulphonic acid 12 7 13 10 9 11.4 12 non-loric surfactants 7 11 3.5 8 7 7.2 6

Sodium coconut sulphate 2.5 2.5 3.0 3.0 2.0 3.1 4.0 TMS / TDS * - - - 6.5 3.5-

Dodecenylic acid 9- to 8.5 9,513.4 7

Tetradecenyl succinic acid 4 - - - 1.0 - 2 g Coconut fatty acid - 16 1.0 - - - 1.0 Oleic acid 3.6 4.0 2.0 2.0 2.5 3.6 3.0

Citric acid 0.9 0.5 to 0.5 0.8 3.5 DTPMPA * * 0.5 0.5 to 0.8 1.5 0.9 0.4

Ethyleneide mother tetraacetic acid - - 1.0 - - - 0.4

Sodium tripolyphosphate - - 15,0 - -

Sodium perborate tetrahydrate - - - - - - 17

Sodium perborate monohydrate 10.4 9 13 13 19 9

Natnumf ormate 0.8 1.0 1.0 0.5 1.0 0.9 1.5

Protease 0.6 0.8 0.5 0.5 0.6 0.7 1.0

Sodium hydroxide to adjust the pH to 10 11 11 10.5 10.5 9 9.5

Perfume, other substances remainder * mixture of tartrate monosuccinate and tartrate disuccinate in a ratio of 80:20 ** diethylenetriaminopentamethylenephosphonic acid n 90786 15

Similar compositions are prepared as follows.

A liquid detergent matrix is prepared by mixing water and organic solvents, surfactants and builders, each of which is one or more. The pH of the matrix is adjusted to 8.5-9 with sodium hydroxide. Add metaborate powder with stirring. This forms a milky suspension. Hydrogen peroxide is then added as an aqueous solution. In this case, small crystals of perborate-10 titethrahydrate are formed. The weight average particle size of the perborate tetrahydrate crystals is typically about 4. As a result of the exothermic reaction, the temperature typically rises to about 40 ° C. The detergent composition is cooled to approximately 25 ° C before the addition of heat-sensitive ingredients such as enzymes and perfume.

Borax can be added to the detergent matrix described above instead of metaborate. In this case, the required amount of sodium hydroxide is added to convert borax to me-20 taborate. The metaborate is then converted to perborate by the addition of hydrogen peroxide. After the composition is cooled to approximately 25 ° C, the heat-sensitive components of the composition are added.

Claims (17)

Aqueous liquid detergent composition having a pH of at least 8, characterized in that it contains a) at least 5% of an organic anionic non-soap surfactant; (b) at least 5% builder; and c) 1 to 40% of perborate bleach in the form of particles having a weight average particle diameter of 0.5 to 20 and formed by in situ recrystallization. Composition according to Claim 1, characterized in that the peroborate bleach particles are formed in situ by a reaction between a borate compound and peroxide. Composition according to Claim 2, characterized in that the borate compound is a metaborate or borax and the peroxide is hydrogen peroxide. Liquid detergent composition according to Claim 1, characterized in that the perborate particles are formed by recrystallization of perborate monohydrate. Liquid detergent composition according to any one of Claims 1 to 4, characterized in that it additionally contains 5 to 70% of a water-miscible organic solvent. Liquid detergent composition according to Claim 5, characterized in that the water-miscible organic solvent is an aliphatic monoalcohol. Liquid detergent composition according to Claim 6, characterized in that the water-miscible organic solvent is ethanol. Liquid detergent composition according to Claim 7, characterized in that the solvent li 90786 contains water and ethanol in a water to ethanol ratio of 8: 1 to 1: 3. Liquid detergent composition according to Claim 8, characterized in that the ratio of water to ethanol is from 5: 1 to 1: 2. Liquid detergent composition according to any one of the preceding claims, characterized in that it has an ionic strength of at least 0.8 mol / l. Liquid detergent composition according to any one of the preceding claims 10, characterized in that it has a pH of at least 9. Liquid detergent composition according to Claim 11, characterized in that it has a pH of at least 9.5. Liquid detergent composition according to any one of the preceding claims, characterized in that it contains less than 4% fatty acid. Liquid detergent composition according to any one of the preceding claims, characterized in that it contains 5 to 40% of a builder which is dodecenyl succinic acid; tetradekenyylimeripihkahappo; do-dekyylmeripihkahappo; an 80:20 mixture of tartrate monosuccinate and tartrate disuccinate; or a mixture of said. A process for preparing a liquid detergent composition according to any one of the preceding claims, characterized in that a) water, an anionic detergent and a builder are mixed; B) the perborate compound is added with stirring. A process for preparing a liquid detergent composition according to any one of claims 1 to 14, characterized in that a) water, an anionic detergent and a builder are mixed; b) adding a borate compound; c) adding peroxide with stirring. Process according to Claim 16, characterized in that the borate compound is a metabolite or borax and the peroxide is hydrogen peroxide. Il 90786