JP2505537B2 - Liquid detergent containing perborate bleach - Google Patents

Description

TECHNICAL FIELD The present invention relates to small particles, that is, a weight average particle diameter of 0.5 to 20 μm.
An aqueous liquid detergent composition containing a perborate bleach in the form of particles having Small particles
Prepared by in situ recrystallization, preferably in situ recrystallization of perborate monohydrate.

BACKGROUND So-called heavy duty liquid detergent compositions such as those currently marketed typically do not contain bleach. Dissolved peroxygen compounds such as hydrogen peroxide interact with other ingredients commonly used in liquid detergents, such as enzymes and perfumes.

Insoluble peroxygen bleach compounds give rise to poor physical stability problems of suspensions prepared therewith.

DE-OS 35 11 515 describes sodium perborate 1
Disclosed is a non-aqueous liquid detergent composition comprising a hydrate and an active agent for perborate. French Patent 2,579,615 discloses a similar non-aqueous composition further comprising a catalase inhibitor. The compositions exemplified in these two patents are:
Contains no anionic surfactant.

J. Dugua and B. Simon, "Crystallization of Sodium Perborate from Aqueous Solution," Journal of Crystal Growth 44 (197).
8), 265-286 discuss the role of surfactants on nucleation and crystal growth of sodium perborate tetrahydrate.

An object of the present invention is to provide an aqueous liquid detergent composition containing perborate particles having a weight average particle size of 0.5 μm to 20 μm. Yet another object of the present invention is to provide a method for preparing particles within a desired size range in-situ.

SUMMARY OF THE INVENTION Aqueous liquid detergent compositions of the present invention have a pH of at least 8, at least 5% organic non-soap anionic surfactant, at least 5% builder, and a weight average particle size of 0.5 μm to 2 μm.
Perborate in the form of particles with 0 μm
Bleach 1% to 40%, preferably 10% to 20% (the particles have been prepared by in situ recrystallization). Preferably, the perborate particles are prepared by in-situ recrystallization of perborate monohydrate, such as sodium perborate monohydrate.

A preferred liquid liquid detergent composition comprises a water-miscible organic solvent 5
% To 70% is further included. The preferred water-miscible organic solvent is a low molecular weight monohydric alcohol. Of these solvents, ethanol is most preferred.

Detergent compositions having a pH of at least 9, more preferably at least 9.5 are preferred here.

DETAILED DESCRIPTION OF THE INVENTION The present invention addresses the problem of formulating an aqueous liquid detergent composition in which small particles of perborate bleach are suspended. For reasons of physical stability, perborate particles have a weight average particle size.
It is necessary to have 0.5 to 20 μm. It is not preferred to prepare such small particles, for example by grinding. The reason is that this process is not economically attractive. Moreover, such small particles in the dry state would pose serious industrial hygiene and safety issues.

Also, detergent compositions containing small perborate particles obtained by milling may have poorer physical stability than compositions containing perborate particles of the same diameter obtained by in-situ recrystallization. Was found. This phenomenon is not fully understood, but it is speculated that particle shape plays a role there.

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

The percentages used here are weight percentages of the liquid detergent composition. Even though the particles may differ in composition (eg, tetrahydrate), the weight percent of perborate is calculated as perborate monohydrate.

The term "in situ recrystallization" relates to the process of preparing perborate particles from larger particles in the presence of a water / anionic surfactant / detergent builder matrix. Therefore, the term encompasses processes involving chemical reactions such as when sodium perborate is produced by the reaction of stoichiometric hydrogen peroxide with sodium metaborate and borax. The term also encompasses processes involving dissolution and recrystallization of perborate monohydrate and subsequent formation of perborate tetrahydrate. Recrystallization may also occur by the perborate monohydrate picking up the water of crystallization, whereby the monohydrate may be recrystallized directly to the tetrahydrate without a dissolution step.

In one aspect of the invention, a perborate compound, such as sodium perborate tetrahydrate or sodium perborate monohydrate, is added to an aqueous liquid detergent containing an anionic surfactant and a detergent builder. The resulting slurry is agitated. During this stirring, the perborate compound
It undergoes a dissolution / recrystallization process. Due to the presence of anionic surfactants and detergent builders, this dissolution / recrystallization process results in particles with the desired particle size.

Monohydrate is preferred for this aspect of the invention as it is more susceptible to recrystallization. The particle size is a weight average particle size unless otherwise specified. A relatively narrow particle size distribution is preferred for reasons of physical stability. That is, less than 10% of the perborate is preferably present in the form of particles having a diameter greater than 25 μm. More preferably, less than 10% (by weight) has a particle size greater than 10 μm.

In a second aspect of the invention, the perborate compound is generated in situ by a chemical reaction. For example, sodium metaborate is added to an aqueous liquid containing anionic surfactant and detergent builder. A stoichiometric amount of hydrogen peroxide is then added with stirring. Stirring is continued until the chemical reaction is complete.

Instead of metaborate, other borate compounds such as borax and boric acid are
May be used. If borax is used as the boron compound, a stoichiometric amount of base, for example sodium hydroxide, is added to ensure the reaction of the borax to metaborate, then the process is carried out in the above case for metaborate conversion. Proceed as you did. Instead of hydrogen peroxide, other peroxides (eg sodium peroxide) may be used as is known in the art.

Usually, perborate tetrahydrate is produced. At temperatures above about 40 ° C., perborate tetrahydrate may slowly convert to the thermodynamically more stable trihydrate. This conversion may itself be used to prepare small particles of trihydrate from large particles of tetrahydrate.

A preferred liquid detergent composition contains a water-miscible organic solvent in addition to water. The solvent reduces the solubility of perborate in the liquid phase of perborate, thereby increasing the chemical stability of the composition.

If sufficient organic solvent is mixed with the water of the composition to affect the solubility of perborate in the liquid phase, the organic solvent need not be completely miscible with water.

Of course, the water-miscible organic solvent must be compatible with the perborate at the pH used. Therefore, polyalcohols with vic hydroxy groups (eg 1,2-propanediol and glycerol) are less desirable.

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

Although the presence or absence of other components plays a role, the amount of available oxygen in the solution is largely determined by the water to organic solvent ratio. The smaller this ratio (ie the more organic solvent is used in the solvent system), the lower the amount of available oxygen in the solution. While this is good for the stability of the bleach system, it is less desirable for the good solubility of other components (eg electrolytes, anionic surfactants).

In practice, the ratio of water to organic solvent is, for most systems,
It 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, the water released or taken up by chemical and physical processes that may occur during the preparation of the detergent composition should be considered. For example, water may be produced in the neutralization of anionic surfactants, while water is taken up in the conversion of metaborate to perborate as well as the conversion of perborate monohydrate to perborate tetrahydrate. Sometimes. Also, water is present in most detergent ingredients and should be considered.

Preferred compositions have an ionic strength of at least 0.8 mol / l, preferably 2-3.5 mol / l, as the ionic strength of the composition is presumed to influence the dissolution / recrystallization process. The ionic strength is calculated under the assumption that all ionic substances present in the composition except perborate are sufficiently dissociated.

The liquid detergent composition of the present invention comprises 5% to 5% of the liquid detergent composition.
60%, preferably 15-40% nonionic surfactant,
It contains an organic surfactant selected from anionic surfactants, zwitterionic surfactants and mixtures thereof. At least 5% of the detergent composition should be an anionic surfactant.

Synthetic anionic surfactants have the general formula R ¹ SO ₃ M (R ¹ has about 9 to about 15 carbon atoms in the alkyl group and straight or branched alkyl groups of about 8 to about 24 carbon atoms. Represents a carbon-hydrogen group selected from the group consisting of alkylphenyl groups). M is typically a salt-forming cation selected from the group consisting of sodium, potassium, ammonium, and mixtures thereof.

A preferred synthetic anionic surfactant is a water-soluble salt of an alkylbenzene sulfonic acid having 9 to 15 carbon atoms in the alkyl group. Another preferred synthetic anionic surfactant is from about 8 to about 24 alkyl groups, preferably about 10 to about.
Water-soluble salts of alkylsulfuric acids or alkylpolyethoxylate ethersulfuric acids having about 18 carbon atoms and having from about 0 to about 20, preferably from about 0 to about 12 ethoxy groups. Other suitable anionic surfactants are described in US Pat.
No. 0,565.

Nonionic surfactants are usually produced by condensing a hydrocarbon having a reactive hydrogen atom such as a hydroxyl, carboxyl, or amide group with ethylene oxide in the presence of an acid catalyst or a base catalyst. As an example, the general formula RA (CH ₂ CH ₂ O) _n H (wherein R represents a hydrophobic moiety, A represents a group carrying a reactive hydrogen atom, and n represents the average number of ethylene oxide moieties) And a compound having R typically has about 8 to 22 carbon atoms. They can also be produced by condensation of propylene oxide with low molecular weight compounds. n is usually about 2 to about 24
Changes.

The hydrophobic portion of the nonionic compound is preferably a primary or secondary linear or branched aliphatic alcohol having from about 8 to about 24 carbon atoms, preferably about 12 to about 20 carbon atoms. A more complete disclosure of suitable nonionic surfactants is found in US Pat. No. 4,111,85.
It can be found in specification No. 5. Mixtures of nonionic surfactants may be desirable.

For zwitterionic surfactants, the aliphatic portion can be linear or branched and one of the aliphatic substituents is from about 8 to about
Has 24 carbon atoms and has at least one other substituent
Included are derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounds containing one anionic water solubilizing group. Particularly preferred zwitterions are those disclosed in
Ethoxylated ammonium sulfonates and ethoxylated ammonium sulfates disclosed in 3,925,262 and 3,929,678.

As the semipolar nonionic surfactant, carbon number is about 8 to about
Water-soluble amine oxide containing one alkyl or hydroxyalkyl moiety of 28 and two moieties selected from the group consisting of alkyl groups of 1 to about 3 carbon atoms and hydroxyalkyl groups, which can optionally be attached to the ring structure. Is mentioned.

Suitable anionic synthetic surfactant salts are selected from the group of sulfonates and sulphates. Such anionic detergents are well known in the detergent art and find wide application in commercial detergents. Preferred anionic synthetic water-soluble sulfonates or sulfates have an alkyl group having about 8 to about 22 carbon atoms in the molecular structure.

Of such preferred anionic surfactant salts example, tallow and the reaction products obtained by sulfating C ₈ -C ₁₈ fatty alcohols derived from coconut oil; alkyl group of about 9 to 15 amino Alkyl benzene sulfonates having carbon atoms; sodium alkyl glyceryl ether sulfonate; ether sulfates of fatty alcohols derived from tallow and coconut oil; coconut fatty acid monoglyceride sulfate and coconut fatty acid monoglyceride sulfonate; and about 8 in the alkyl chain.
Is a water-soluble salt of paraffin sulfonic acid having about 22 carbon atoms. Sulfonated olefin surfactants such as those detailed in US Pat. No. 3,332,880 can also be used. Neutralizing cations for anionic synthetic sulfonates and / or sulphates are represented by the usual cations, such as sodium, potassium, which are widely used in detergent technology.

Particularly preferable anionic synthetic surfactant component here is
Represented by a water-soluble salt of an alkylbenzene sulphonic acid, preferably sodium alkylbenzene sulphonate, preferably sodium alkylbenzene sulphonate having about 10 to 13 carbon atoms in the alkyl group.

A preferred class of nonionic ethoxylates has 12 carbon atoms.
~ 15 fatty alcohols and about 4 to 10 moles of ethylene oxide per mole of fatty alcohol. Suitable ethoxylates of this type include condensation products of C ₁₂ -C ₁₅ oxo alcohols with 7 or 9 moles of ethylene oxide per mole of alcohol; narrow-cut C ₁₄ -C ₁₅ oxo alcohols and fatty (oxo) alcohols. 1 condensate of molar per 7 or 9 moles of ethylene oxide; narrow-cut C ₁₂ -C ₁₃ fatty (oxo) condensates of alcohol and fatty alcohol per mole 6.5 moles of ethylene oxide; and the degree of ethoxylation (EO mol / fat condensates of C ₁₀ -C ₁₄ coconut fatty alcohol with an alcohol mole) 5-8 and the like. The fatty oxoalcohols are predominantly linear, but can have some degree of branching, especially short chains such as methyl branching, depending on the processing conditions and the raw olefin.

A degree of branching of 15% to 50% (wt%) is often found in commercial oxo alcohols.

Also, the preferred nonionic ethoxylated component can be represented by a mixture of two separately ethoxylated nonionic surfactants having different degrees of ethoxylation.
For example, nonionic ethoxylate surfactants having 3 to 7 moles ethylene oxide per mole hydrophobic moiety and secondary ethoxylates having 8 to 14 moles ethylene oxide per mole hydrophobic moiety. Preferred nonionic ethoxylated mixture comprises a lower ethoxylate which is the condensation product of C ₁₂ -C ₁₅ oxo alcohols and fatty oxo alcohols per mole to about 3-7 moles of ethylene oxide with up to branch 50% (by weight), Have branching higher than 50% (by weight)
It contains a C ₁₆ -C ₁₉ oxo alcohol and a higher ethoxylate which is a condensate of about 8 to 14 moles of ethylene oxide per mole of branched oxo alcohol.

The liquid detergent compositions of the present invention optionally contain a fatty acid component, preferred saturated fatty acids have 10 to 16 carbon atoms, 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 composition of the present invention.
In fact, one of the desirable features of the composition is that it is compatible with such detergent enzymes. Suitable enzymes include detergent proteases, amylases, lipases and cellulases. Enzyme stabilizers for use in aqueous liquid detergents are well known. Salts of formic acid, for example sodium formate, are preferred here. The amount of this stabilizer is typically 0.5% to 2%.

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

Examples of organic builders are represented by polyacids such as citric acid, nitrilotriacetic acid, and mixtures of tartrate monosuccinate and tartrate disuccinate. Preferred builders for use herein are citric acid and alkyl or alkenyl substituted succinic acid compounds where the alkyl or alkenyl has from 10 to 16 carbon atoms. One example of this group of compounds is dodecenyl succinic acid. Polymeric carboxylate builders can also be used, including polyacrylates, polyhydroxyacrylates and polyacrylate / polymaleate copolymers.

The composition may contain a series of further optional ingredients, usually used in additive amounts, usually less than about 5%. Examples of such additives include polyacids, enzymes and enzyme stabilizers, antifoams, opacifiers, agents that improve mechanical compatibility in connection with enamel coated surfaces, bactericides, dyes, fragrances, Whitening agents and the like can be mentioned.

The liquid composition of the present invention may contain further additives in an amount of 0.05-2%.

These additives include polyaminocarboxylates such as ethylenediaminotetraacetic acid, diethylenetriaminopentaacetic acid, ethylenediaminodisuccinic acid or their water-soluble alkali metal salts. Other additives include organophosphonic acids. Particularly preferred are ethylenediaminotetramethylenephosphonic acid, hexamethylenediaminotetramethylenephosphonic acid, diethylenetriaminopentamethylenephosphonic acid and aminotrimethylenephosphonic acid.

The composition may further contain bleach stabilizers of the type known in the art. If a process involving the use of hydrogen peroxide is used for the preparation of liquid detergents, typical bleach stabilizers may be present as they are introduced in the case of commercial hydrogen peroxide. Examples of suitable bleach stabilizers include:
Examples include ascorbic acid, dipicolinic acid, sodium stannate and 8-hydroxyquinoline, which range from 0.01 to
It can be incorporated into these compositions in an amount of 1%.

The beneficial use of the composition under various conditions of use may require the use of antifoam agents. Generally all detergent defoamers are available, but alkylated polysiloxanes such as dimethyl polysiloxane, often also referred to as silicone, are preferred for use herein. Silicone often does not exceed 1.5%, most preferably 0.1%
Used in an amount of ~ 1.0%.

It may also be desirable to utilize opacifiers, as they contribute to the uniform appearance of concentrated liquid detergent compositions. An example of a suitable opacifier is LYTRON from Monsanto Chemical Corporation.
Examples of 621 include polystyrene known commercially. Opacifiers are often used in amounts of 0.3% to 1.5%.

The liquid detergent compositions of the present invention may further include agents that improve washer compatibility, particularly in connection with enamel coated surfaces.

Further known anti-redeposition and / or compatibilizer 0.1%
It may be desirable to add ~ 5%. Examples of such additives include sodium carboxymethyl cellulose; hydroxy-C _1-6 alkyl cellulose; polycarboxylic acid homopolymer or copolymer components, for example,
Polymaleic acid, a copolymer of maleic anhydride and methyl vinyl ether in a molar ratio of 2: 1 to 1: 2; and an ethylenically unsaturated monocarboxylic acid monomer having 5 or less carbon atoms, preferably 3 or 4 carbon atoms, for example, (Meth) acrylic acid and 6 carbon atoms
Hereinafter, preferably a copolymer of 4 with an ethylenically unsaturated dicarboxylic acid monomer (the molar ratio of the monomer is in the range of 1: 4 to 4: 1, the above copolymer is the European Patent Application No. 0 066 915).

 The following example illustrates the invention and facilitates its understanding.

Liquid detergent compositions are prepared by mixing the indicated ingredients in the indicated proportions: The following compositions are prepared in the same way.

A similar composition is prepared as follows.

A liquid detergent matrix is prepared by mixing water, an organic solvent (one or more, a surfactant (one or more), and a builder substance (one or more). The matrix is adjusted to pH 8.5-9 with sodium hydroxide. The metaborate powder is added with stirring, a milky white suspension is obtained, and then hydrogen peroxide is added as an aqueous solution.
Small crystals of hydrate are formed. Typically, perborate tetrahydrate crystals have a weight average particle size of about 4 μm. As a result of the exothermic reaction, the temperature typically rises to about 40 ° C.
Before adding heat-sensitive ingredients such as enzymes and fragrances, wash the detergent composition
Cool to 25 ° C.

Borax may be added to the detergent matrix instead of metaborate. Add the amount of sodium hydroxide needed to convert the borax to metaborate. The metaborate is then converted to perborate by the addition of hydrogen peroxide. After cooling to about 25 ° C, the heat sensitive component of the composition is added.

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Claims (17)

(57) [Claims] 1. A pH of at least 8; (a) at least 5 organic non-soap anionic surfactants.
%, (B) at least 5% builder, and (c) 1% to 40% perborate bleach in the form of particles having a weight average particle size of 0.5 μm to 20 μm.
Wherein said particles are prepared by in-situ recrystallization. 2. The composition of claim 1 wherein the perborate bleach particles are prepared by the in situ reaction of the borate compound with a peroxide. 3. The composition according to claim 2, wherein the borate compound is metaborate or borax and the peroxide is hydrogen peroxide. 4. The liquid detergent composition according to claim 1, wherein the perborate particles are prepared by recrystallization of perborate monohydrate. 5. Further comprising 5% to 70% of a water-miscible organic solvent,
The liquid detergent composition according to any one of claims 1 to 4. 6. The liquid detergent composition according to claim 5, wherein the water-miscible organic solvent is an aliphatic monoalcohol. 7. The water-miscible organic solvent is ethanol,
The liquid detergent composition according to claim 6. 8. The solvent is a water to ethanol ratio of 8: 1 to 1: 3.
8. A liquid detergent composition according to claim 7 comprising water and ethanol. 9. The liquid detergent composition according to claim 8, wherein the ratio of water to ethanol is 5: 1 to 1: 2. 10. A liquid detergent composition according to claim 1, which has an ionic strength of at least 0.8 mol / l. 11. A liquid detergent composition according to claim 1, which has a pH of at least 9. 12. The liquid detergent composition according to claim 11, which has a pH of at least 9.5. 13. The liquid detergent composition according to claim 1, which contains less than 4% of fatty acids. 14. Dodecenyl succinic acid; tetradecenyl succinic acid; dodecyl succinic acid; 80:20 mixture of tartrate monosuccinate and tartrate disuccinate;
The liquid detergent composition according to any one of claims 1 to 13, comprising 5% to 40% of a builder selected from citric acid; and a mixture thereof. 15. The liquid detergent composition according to claim 1, wherein (a) water is mixed with an anionic detergent and a builder, and (b) the perborate compound is added with stirring. How to make things. 16. The method according to claim 1, wherein (a) water is mixed with an anionic detergent and a builder, (b) a borate compound is added, and (c) a peroxide is added with stirring. The method for producing the liquid detergent composition according to item 1. 17. The method according to claim 16, wherein the borate compound is metaborate or borax and the peroxide is hydrogen peroxide.