EP0514434B1

EP0514434B1 - Liquid bleach composition

Info

Publication number: EP0514434B1
Application number: EP91903665A
Authority: EP
Inventors: Hidde Frankena; Johannes Cornelis Van De Pas
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1990-02-08
Filing date: 1991-02-07
Publication date: 1997-05-21
Anticipated expiration: 2011-02-07
Also published as: WO1991012309A3; JPH05502471A; AU7187491A; AU643503B2; EP0514434B2; EP0514434A1; WO1991012309A2; CA2073432A1

Abstract

A liquid detergent composition comprising an aqueous base, one or more detergent active materials and a bleach material, said composition comprising from 5 to 32 % by weight of solvent materials.

Description

The present invention relates to a liquid detergent composition comprising an aqueous base, detergent active materials and a bleach material.
Liquid aqueous detergent compositions comprising one or more bleach materials have been described in EP 293 040, EP 294 904, EP 378 261 and EP 378 262 (P&G).
EP-A-293,040 discloses high pH, aqueous liquid detergent compositions comprising anionics, at most partially dissolved bleach material and water-miscible organic solvent. The document teaches the use of high water/solvent levels as well as relatively high organic solvent levels and relatively low water levels to stabilise the bleach material.
A problem of the formulations as disclosed in these patent application is the relatively low level of active materials. These low active levels generate the need for high dosages of liquid detergent materials to be used per washing cycle.
Surprisingly it has now been found that stable liquid detergent compositions can be formulated which do not suffer from the above disadvantage, if specific levels of solvent materials are used.
Accordingly the present invention relates to a liquid detergent composition comprising aqueous solvent material, 10-60 % by weight of detergent active materials and 1-40 % by weight of bleach material selected from perborates and percarbonates, wherin said composition is structured and comprises from 5 to 32 % by weight of solvent material comprising water of a mixture of water and a water-miscible solvent, with a weight ratio of water to water-miscible solvent above 1:1.
For the purpose of the present invention the term solvents is intended to cover water and water-miscible solvents. Examples of water-miscible solvents are for example described in EP 293 040.

bleach material

Compositions according to the present invention comprise a bleach material, which is preferably a peroxygen bleach. This bleach component may be present in the system in dissolved form, but preferred is that no or only part of the peroxygen bleach is solubilized, the remaining part preferably being present as solid peroxygen particles which are suspended in the system.
Examples of suitable bleach compounds include hydrogen peroxide, the perborates, persulfates, peroxy disulfates, perphosphates, calciumperoxides and the crystalline peroxyhydrates formed by reacting hydrogen peroxide with urea or alkali metal carbonate. Also encapsulated bleaches may be used. Preferred bleaches are only partially soluble in the system. Especially preferred is the use of perborate or percarbonate bleaches.
Typical amounts of bleach will be between 1 and 40 % by weight of the aqueous composition, more preferred from 7 to 30%, especially preferred from 10 to 25 % by weight of the composition.
The weight average particle size of the bleach particles is preferably from more than 0.5, more preferably more than 20 micrometer, especially preferably from 22-60 micrometer, even more preferably from 25 to 50 micrometer, most preferably from 30 to 45 micrometer. A preferred method for determining the weight average particle size involves the making of microscopy pictures of the liquid detergent composition at a magnification of between 50 and 600 (preferably about 150), followed by the manual or automatic counting of the visible particles, measuring the particle diameter for each particle and calculating the weight average particle size for the visible particles.

detergent active materials

Compositions of the present invention also comprise detergent active materials. In the widest definition the detergent active materials in general, may comprise one or more surfactants, and may be selected from anionic, cationic, nonionic, zwitterionic and amphoteric species, and (provided mutually compatible) mixtures thereof. For example, they may be chosen from any of the classes, sub-classes and specific materials described in "Surface Active Agents" Vol. I, by Schwartz & Perry, Interscience 1949 and "Surface Active Agents" Vol. II by Schwartz, Perry & Berch (Interscience 1958), in the current edition of "McCutcheon's Emulsifiers & Detergents" published by the McCutcheon division of Manufacturing Confectioners Company or in Tensid-Taschenburch", H. Stache, 2nd Edn., Carl Hanser Verlag, Munchen & Wien, 1981.
Suitable nonionic surfactants include, in particular, the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are alkyl (C₆-C₁₈) primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called nonionic detergent compounds include long chain tertiary amine oxides, long chain tertiary phosphine oxides and dialkyl sulphoxides.
Also possible is the use of salting out resistant active materials, such as for example described in EP 328 177, especially the use of alkyl poly glycoside surfactants, such as for example disclosed in EP 70 074.
Suitable anionic surfactants are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher acyl radicals. Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher (C₈-C₁₈) alcohols produced for example from tallow or coconut oil, sodium and potassium alkyl (C₉-C₂₀) benzene sulphonates, particularly sodium linear secondary alkyl (C₁₀-C₁₅) benzene sulphonates; sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum; sodium coconut oil fatty monoglyceride sulphates and sulphonates; sodium and potassium salts of sulphuric acid esters of higher (C₈-C₁₈) fatty alcohol-alkylene oxide, particularly ethylene oxide, reaction products; the reaction products of fatty acids such as coconut fatty acids esterified with isethionic acid and neutralised with sodium hydroxide; sodium and potassium salts of fatty acid amides of methyl taurine; alkane monosulphonates such as those derived by reacting alphaolefins (C₈-C₂₀) with sodium bisulphite and those derived from reacting paraffins with SO₂ and Cl₂ and then hydrolysing with a base to produce a random sulponate; and olefin sulphonates, which term is used to describe the material made by reacting olefins, particularly C₁₀-C₂₀ alpha-olefins, with SO₃ and then neutralising and hydrolysing the reaction product. The preferred anionic detergent compounds are sodium (C₁₁-C₁₅) alkyl benzene sulphonates and sodium or potassium primary (C₁₀-C₁₈) alkyl sulphates.
It is also possible, and sometimes preferred, to include an alkali metal soap of a fatty acid, especially a soap of an acid having from 12 to 18 carbon atoms, for example oleic acid, ricinoleic acid, and fatty acids derived from castor oil, alkylsuccinic acid, rapeseed oil, groundnut oil, coconut oil, palmkernel oil or mixtures thereof. The sodium or potassium soaps of these acids can be used.
The total detergent active material may be present at from 5% to 70% by weight of the total composition, for example from 10% to 60% and typically from 20% to 50% by weight.

solvents

Compositions according to the invention comprise from 5 to 32 % by weight of solvent materials which are selected from the group of water and water-miscible solvents. Preferred levels of solvent materials are from 10 to 30 % by weight of the compostion, more preferably from 15 to 29 %, most preferably from 20 to 25 %.
Suitable water-miscible solvents are for example lower (C₁-C₅) alcohols such as ethanol and iso-propanol, low molecular weight (<1,000) Polyethyleneglycols, alkyleneglycols for example propylene glycol etc. Other suitable water-miscible solvents are described in EP 293 040. For the purpose of this invention glycerol is not a solvent.
Preferably the solvent material comprises either water alone or a mixture of water and one or more water-miscible solvents. The preferred weight ratio of water to water-miscible solvent is more than 1 : 1, more preferably from 2 : 1 to 500 : 1, most preferably from 3 : 1 to 50 : 1.

optional ingredients

Compositions of the invention are structured. Structured liquids of the invention may be internally structured whereby the structure is formed by the detergent active materials in the composition or externally structured, whereby the structure is provided by an external structurant. Preferably compositions of the invention are internally structured. Most preferably compositions of the invention comprise a structure of lamellar droplets of detergent active materials.
Some of the different kinds of active-structuring which are possible are described in the reference H.A. Barnes, "Detergents", Ch.2. in K. Walters (Ed), "Rheometry: Industrial Applications", J. Wiley & Sons, Letchworth 1980. In general, the degree of ordering of such systems increases with increasing surfactant and/or electrolyte concentrations. At very low concentrations, the surfactant can exist as a molecular solution, or as a solution of spherical micelles, both of these being isotropic. With the addition of further surfactant and/or electrolyte, structured (anisotropic) systems can form. They are referred to respectively, by various terms such as rod-micelles, planar lamellar structures, lamellar droplets and liquid crystalline phases. Often, different workers have used different terminology to refer to the structures which are really the same. For instance, in European patent specification EP-A-151 884, lamellar droplets are called "spherulites".
The presence and identity of a surfactant structuring system in a liquid may be determined by means known to those skilled in the art for example, optical techniques, various rheometrical measurements, x-ray or neutron diffraction, and sometimes, electron microscopy.
When the compositions are of lamellar droplet structure then in many cases it is preferred for the aqueous continuous phase to contain dissolved electrolyte. As used herein, the term electrolyte means any ionic water soluble material. However, in lamellar dispersions, not all the electrolyte is necessarily dissolved but may be suspended as particles of solid because the total electrolyte concentration of the liquid is higher than the solubility limit of the electrolyte. Mixtures of electrolytes also may be used, with one or more of the electrolytes being in the dissolved aqueous phase and one or more being substantially only in the suspended solid phase. Two or more electrolytes may also be distributed approximately proportionally, between these two phases. In part, this may depend on processing, e.g. the order of addition of components. On the other hand, the term "salts" includes all organic and inorganic materials which may be included, other than surfactants and water, whether or not they are ionic, and this term encompasses the sub-set of the electrolytes (water soluble materials).
The selection of surfactant types and their proportions, in order to obtain a stable liquid with the required structure will be fully within the capability of those skilled in the art. However, it can be mentioned that an important sub-class of useful compositions is those where the detergent active material comprises blends of different surfactant types. Typical blends useful for fabric washing compositions include those where the primary surfactant(s) comprise nonionic and/or a non-alkoxylated anionic and/or an alkoxylated anionic surfactant.
In the case of blends of surfactants, the precise proportions of each component which will result in such stability and viscosity will depend on the type(s) and amount(s) of the electrolytes, as is the case with conventional structured liquids.
Preferably though, the compositions contain from 1% to 60%, especially from 10 to 45% of a salting-out electrolyte. Salting-out electrolyte has the meaning ascribed to in specification EP-A-79 646, that is salting-out electrolytes have a lyotropic number of less than 9.5. Optionally, some salting-in electrolyte (as defined in the latter specification) may also be included, provided it is of a kind and in an amount compatible with the other components and the composition is still in accordance with the definition of the invention claimed herein.
Some or all of the electrolyte (whether salting-in or salting-out), or any substantially water insoluble salt which may be present, may have detergency builder properties. In any event, it is preferred that compositions according to the present invention include detergency builder material, some or all of which may be electrolyte. The builder material is any capable of reducing the level of free calcium ions in the wash liquor and will preferably provide the composition with other beneficial properties such as the generation of an alkaline pH, the suspension of soil removed from the fabric and the dispersion of the fabric softening clay material. Preferably the salting-out electrolyte comprises citrate.
Preferably the weight ratio of water to salting-out electrolyte is from 10 : 1 to 1 : 1, more preferably from 8 : 1 to 2 : 1. The weight ratio of water-miscible solvent to salting out electrolyte is preferably from 1 : 1 to 1 : 20, more preferably 1 : 2 to 1 : 10, most preferably 1 : 8 to 1 : 4.
Examples of phosphorus-containing inorganic detergency builders, when present, include the water-soluble salts, especially alkali metal pyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific examples of inorganic phosphate builders include sodium and potassium tripolyphosphates, phosphates and hexametaphosphates. Phosphonate sequestrant builders may also be used.
Examples of non-phosphorus-containing inorganic detergency builders, when present, include water-soluble alkali metal carbonates, bicarbonates, silicates and crystalline and amorphous aluminosilicates. Specific examples include sodium carbonate (with or without calcite seeds), potassium carbonate, sodium and potassium bicarbonates, silicates and zeolites.
Examples of organic detergency builders, when present, include the alkaline metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates, polyacetyl carboxylates and polyhydroxysulphonates. Specific examples include sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid, nitrilitriacetic acid, oxydisuccinic acid, CMOS, TMS, TDS, melitic acid, benzene polycarboxylic acids and citric acid.
Preferably the level of non-soap builder material is from 0-50% by weight of the composition, more preferred from 5-40%, most preferred 10-35%.
In the context of organic builders, it is also desirable to incorporate polymers which are only partly dissolved, in the aqueous continuous phase as described in EP 301.882. This allows a viscosity reduction (due to the polymer which is dissolved) whilst incorporating a sufficiently high amount to achieve a secondary benefit, especially building, because the part which is not dissolved does not bring about the instability that would occur if substantially all were dissolved. Typical amounts are from 0.5 to 4.5% by weight.
It is further possible to include in the compositions of the present invention, alternatively, or in addition to the partly dissolved polymer, yet another polymer which is substantially totally soluble in the aqueous phase and has an electrolyte resistance of more than 5 grams sodium nitrilotriacetate in 100ml of a 5% by weight aqueous solution of the polymer, said second polymer also having a vapour pressure in 20% aqueous solution, equal to or less than the vapour pressure of a reference 2% by weight or greater aqueous solution of polyethylene glycol having an average molecular weight of 6000; said second polymer having a molecular weight of at least 1000. Use of such polymers is generally described in our EP 301,883. Typical levels are from 0.5 to 4.5% by weight.
The viscosity of compositions according to the present is preferably less than 2500 mPa.s, more preferred less than 2000 mPas, most preferred less than 1500 mPa.s, especially preferred between 30 and 900 mPa.s at 21 s^-1.
One way of regulating the viscosity and stability of compositions according to the present invention is to include viscosity regulating polymeric materials.
Viscosity and/or stability regulating polymers which are preferred for incorporation in compositions according to the invention include deflocculating polymers having a hydrophilic backbone and at least one hydrophobic side chain. Such polymers are for instance described in our copending European application EP 89201530.6 (EP 346 995). Preferably the amount of viscosity regulating polymer is from 0.1 to 5% by weight of the total composition, more preferred from 0.2 to 2%.
Compositions of the invention may also comprise materials for adjusting the pH. For lowering the pH it is preferred to use weak acids, especially the use of organic acids is preferred, more preferred is the use of C 1-8 carboxylic acids, most preferred is the use of citric acid. The use of these pH lowering agents is especially preferred when the compositions of the invention contain enzymes such as amylases, proteases and lipolases.
Apart from the ingredients already mentioned, a number of optional ingredients may also be present, for example lather boosters such as alkanolamides, particularly the monoethanolamides derived from palm kernel fatty acids and coconut fatty acids, fabric softeners such as clays, amines and amine oxides, lather depressants, inorganic salts such as sodium sulphate, and, usually present in very minor amounts, fluorescent agents, perfumes, germicides colourants and enzymes such as proteases, cellulases, amylases and lipases (including Lipolase (Trade Mark) ex Novo). Suitable examples of protease enzymes are Savinase (ex Novo), Maxatal (gist-brocades), Opticlean (ex MKC) or AP122 (ex Showa Denko), Alcalase, Maxatase, Esperase, Optimase, proteinase K and subtilisin BPN. Suitable lipolases are for example Lipolase (ex Novo), Amano lipases, Meito lipases, Lipozym, SP 225, SP 285, Toyo Jozo lipase. Suitable amylases are for example Termamyl (TM of Novo) and Maxamyl. Suitable cellulases include Celluzym (ex Novo).
Liquid detergent compositions according to the invention are preferably physically stable in that they show less than 2% by volume phase separation upon storage for 21 days after preparation at 25°C.
Liquid detergent compositions according to the invention are preferably volume stable in that they show less than 25% preferably less than 10%, more preferably less than 5% volume increase during storage at a temperature between 20 and 37°C for a period of three months after preparation.
Also preferably compositions according to the invention have solid suspending properties, most preferably they do not yield any visible sedimentation after storage for three weeks at 21 °C.
Compositions of the present invention may comprise one or more bleach precursor agents. A well-known example of such an agent is TAED. Preferably the bleach precursor agent is present in the system in at least partly undissolved form. One way of ensuring that the precursor is present in undissolved form is to increase the amount of electrolyte in the composition, therewith reducing the solubility of the precursor in the system. Suitable electrolytes for this purpose are for instance the at least partially water soluble carbonate, sulphate and halogenide salts.
Compositions of the invention may also advantageously comprise one or more ingredients for the stabilization of bleach materials. Suitable materials are for example metaborate electrolytes and magnesium salts.
In use the detergent compositions of the invention will be diluted with wash water to form a wash liquor for instance for use in a washing machine. The concentration of liquid detergent composition in the wash liquor is preferably from 0.05 to 10 %, more preferred from 0.1 to 3% by weight.
To ensure effective detergency, the liquid detergent compositions preferably are alkaline, and it is preferred that they should provide a pH within the range of about 7.0 to 12, preferably about 8 to about 11, when used in aqueous solutions of the composition at the recommended concentration. To meet this requirement, the undiluted liquid composition should preferably be of a pH above 7, for example about pH 8.0 to about 12.5. It should be noted that an excessively high pH, e.g. over about pH 13, is less desirable for domestic safety.
Compositions according to the invention may be prepared by any method for the preparation of liquid detergent compositions. A preferred method involves the addition of the water-miscible solvent and the salting out electrolytes (if any) to water, followed by the addition of the actives, the bleach ingredient and the remaining ingredients.
The invention will now be illustrated by way of the following Examples.

Example I

The following compositions may be prepared by mixing the ingredients in the listed order:

Ingredient % wt A B

water 29 24

ethanol -- 5

citrate/citric acid¹⁾ 10 10

ABS 28 28

Synperonic A7 12 12

polymer²⁾ 1 1

perborate.monohydrate 20 20

¹⁾ this mixture is used to adjust the pH to 8.5

²⁾ polymer A-11 as described in EP 346 995

Example II

The following compositions were made by adding the electrolyte together with the minor ingredients except for the perfume and the enzymes to water of elevated temperature, followed by the addition of the deflocculating polymer and then the detergent active materials as a pre-mix under stirring and thereafter cooling the mixture and adding the enzymes and the perfumes.

Ingredient (% wt)	a	b	c	d
NaLas	21	24.5	21	21
Synperonic A7	9	10.5	9	9
Nametaborate.2aq	2.6	2.5	2.6	2.6
Nacitrate.2aq	15.5	15.5	24.7	19.6
Dequest 2060S	0.4	0.4	0.4	0.4
Perborate.tetra	20	15	15	20
Alcalase	0.75	0.75	0.75	0.75
CaCl₂.2aq	0.15	0.15	0.15	0.15
Tinopal CBS-X	0.1	0.1	0.1	0.1
Silicon DB100	0.25	0.25	0.25	0.25
Perfume	0.3	0.3	0.3	0.3
polymer	1	1	1	1
water	28.95	28.95	28.95	28.95
pH	9	9	9	9
Viscosity	1650	3730	1960	3580
Volume stability	0%	0%	0%	0%
Phase separation	stable	stable	stable	stable
Bleach stability	95%	94%	98%	96%

In the above table NaLAS refers to sodium linear C₁₂ alkyl benzene sulphonate, the polymer was a deflocculating polymer as disclosed as A44 in EP 346 995, the bleach was added as a 65 % dispersion in water (Proxsol ex ICI), where necessary the pH was adjusted with citric acid.
The viscosity was measured in mPa.s at 21 s^-1, the volume stability indicates the maximum volume increase during storage for three months at ambient temperature, the bleach stability indicates the percentage of bleach left after storage for 4 weeks at 37 °C. Compositions c and d showed some solid sedimentation due to some crystallization of citrate.
The above results clearly show that pourable liquid detergent products can be made which contain stable bleach ingredients, when only low levels of solvent materials are used.

Example III

The following composition was prepared by adding the electrolyte together with the minor ingredients except for the perfume and the enzymes to water of elevated temperature, followed by the addition of the detergent active material as a premix under stirring and thereafter cooling the mixture and adding the enzymes, perfumes and the bleach.

The obtained product had the following characteristics:

	A
Volume stability (% volume increase, 3 months 25°C)	4
clear layer separation (3 weeks 37°C)	no
solid sedimentation (3 week 37°C)	no
Viscosity 21 s^-1	1,350
Viscosity 10^-4 s^-1	200,000
dissolved perborates ⁵⁾	3
bleach activity (2 months ambient T)	99
enzyme activity (2 months ambient T)²⁾	65

Example IV

The following formulations may be prepared by adding the ingredients to water in the listed order.

Ingredient	Composition % wt
	1	2
Na-Dobs	9.1	17.3
Synperonic A7	3.6	1.8
Na Stearate	--	0.9
Glycerol	8.1	3.0
NaOH	1.0	--
Na-metaborate	5.8	2.0
Na-perborate	20	10
Na-citrate	--	5.0
Citric acid	1.5	--
Zeolite A4	25.3	30.0
NaCMC	--	0.3
Tinopal CBS-X	--	0.13
Perfume	--	0.22
Alcalase 2.34L	--	0.5
Polymer ^*)	0.5	0.5
Water	--to 100%----

^*) polymer A-11 as described in EP 89201530.6 (EP 346 995).

Example V

The following detergent compositions may be prepared as in example IV.

Ingredient	Composition % wt
	1	2
Na-Dobs	10.2	--
K-Dobs	--	10.7
Synperonic A7	19.3	19.3
Na Oleate	10.3	--
K Oleate	--	10.3
Glycerol	5.0	5.0
Na-metaborate	3.5	3.5
Na-perborate.4H₂O	10.0	15.0
Na-citrate 2aq	10.0	--
Na₂CO₃	--	4.0
Sokolan CP5	2.5	--
Dequest 2066	0.4	--
Mg-silicate	--	0.4
Silicon DB 100	0.3	0.3
Tinopal CBS-X	0.5	0.5
Savinase	0.1	0.1
Amylase	0.1	0.1
Perfume	0.1	0.1
Dye	0.3	0.3
Polymer ^*)	1.0	1.0

^*) polymer A-11 as disclosed in EP 89201530.6 (EP 346 995).

Claims

A liquid detergent composition comprising aqueous solvent material, 10-60% by weight of detergent active material and 1-40% by weight of bleach material selected from perborates and percarbonates, wherein said composition is structured and comprises from 5 to 32% by weight of solvent material comprising water or a mixture of water and a water-miscible solvent, with a weight ratio of water to water-miscible solvent above 1:1.
A liquid detergent composition according to claim 1 comprising from 1 to 40% by weight of perborate bleach material.
A liquid detergent composition according to claim 1 or 2 comprising from 20 to 50% by weight of detergent active material.
A liquid detergent composition according to any of the claims 1-3 further comprising from 1-60% by weight of salting-out electrolytes and from 0 to 50% by weight of non-soap materials.
A liquid detergent composition according to any of the claims 1-4 in which the aqueous solvent material comprises only water as a solvent.
A liquid detergent composition according to any of the claims 1-5 comprising a structure of lamellar droplets of detergent active material.
Use of compositions according to any of the claims 1-6 for the washing of fabrics.