CA2000481A1

CA2000481A1 - Softening compositions

Info

Publication number: CA2000481A1
Application number: CA 2000481
Authority: CA
Inventors: Annemieke C. M. Donkers; Julie H. Sheppard
Original assignee: Dow Corning SA
Current assignee: Dow Silicones Belgium SPRL
Priority date: 1988-10-12
Filing date: 1989-10-11
Publication date: 1990-04-12
Also published as: FR2637620A1; DE3933971A1; GB8823875D0; FR2637620B1; GB8919257D0; GB2223768A; GB2223768B; DE3933971C2

Abstract

Abstract of the Disclosure A liquid rinse cycle softener composition comprises up to 50% by weight of (A) an organic cationic compound which is substantive to water rinse on textile fibres, from 0.01 to 5% by weight (B) a silicone foam controlling agent comprising a liquid polydiorganosiloxane and solid hydrophobic filler particles and, (C) a nonionic or cationic surfactant capable of emulsifying, at least to some extent, the silicone foam controlling agent.
Component (C) is preferably present in a weight ratio of component (B) to component (C) from 1/1 to 1/5 and is preferably a polydiorganosiloxane oxyalkylene copolymer. A method of treating textile fabrics by applying the compositions is also claimed.

Description

3~

SOFTENING COMPOSITIONS

The present invention relates to softening composi-tions, more particularly to softening compositions used as rinse cycle softeners in laundry washing operations.
Rinse cycle softeners have been known for a long time and are described in a number of patent applications and articles. Some rinse cycle softeners comprise in their formulation silicone components. G.B. Patent Specification 1 549 180, for example, describes compositions for treating fabrics in an aqueous bath such as the final rinse after a washing process to improve various properties of the fabric, comprising a fabric substantive cationic compound and an emulsion of a predominantly linear di(Cl-C5) alkyl or aralkyl siloxane, having a viscosity of at least 100 mm2/s and up to 8000 mm2/s; the weight ratio of the siloxane content of the emulsion to the cationic compound being in the range from 5:1 to 1:100. The compositions described in said Patent Specification are claimed to provide easier ironing, anti-static properties, pleasanter feel of the fabrics and soil release properties.
~etergent compositions have also been developed which include fabric softening components. It is intended that these components are carried through to the rinse cycle of the washing process. However, washing processes usually have a number of rinse cycles, and the softening composi-tion should preferably only be released in the last cycle to ensure maximum effect. The advantage of such detergent compositions lies in the fact that the user only has to add one dosage of cleaning materials to ~he washing machine.
Many people still prefer to control the amount of softener used on specific fabrics. There is, therefore, still a need for a rinse cycle softener which is to be added at the :.,. - ; ., ' ~ .

last rinse cycle. Front loading washing machines are usually provided with a multi compartment feeder tray, in which detergent dosages for prewash and main wash and softener compositions can be supplied in different compart-ments at the onset of the washing cycle, thus onlyrequiring the user to measure ingredients out once per washing process.
There has been a move towards more concentrated rinse cycle softener compositions. These have the advantage of requiring less storage space than the less concentrated compositions. However, because of the change in formula-tion as a consequence of concentrating the softener compo-sitions, there is an inherent oam problem with some of these compositions when they are introduced in the rinse cycle of the washing process. It is regarded as aestheti-cally unsatisfactory to retain a high foam level in the rinse cycle of a washing process. The user of the washing machine, particularly the housewife, tends to relate excessive foam levels in the rinse cycle with inefficient rinsing. When the washing liquor is drained off at the end of the washing cycle prior to the first rinsing cycle there is usually a certain amount of detergent which is carried through from one cycle to the next. This also causes some unwanted foaming in the rinse cycle. There is therefore a need to control the foam in the rinse cycle of the washing process, more particularly in the last rinse cycle into which a softener composition is released.
G.B. Patent Specification 2 185 752 describes a detergent composition which provides rinse cycle suds control and comprises a surfactant, detergency builder and rinse cycle suds control prills comprising fatty acid soap, at least one quaternary ammonium salt and at least one silicone fluid suds depressor. The silicone fluid suds depressor is described as a polysiloxane con-taining moieties of the general structure -(R'R''SiO)X-, wherein x has a val~le of from 20 to about 2000 and R' and R" are alkyl or aryl groups. Such prills are effective in a solid powder detergent, and rely on the pH of the washing liquor and subsequent change of pH when entering the rinse cycle for releasing the components. This means that the composi-tion will be released, at least in part, from the first rinse cycle onwards. Liquid rinse cycle softeners also require a diferent solution to the problem of controlling foam.
We have now found that improved rinse cycle softener compositions can be produced by introducing into them a silicone foam controlling agent, comprising a polydiorgano-siloxane and hydrophobic solid particles, and a nonionic orcationic suractant which is able to emulsify the foam controlling compound to some extent.
The invention provides in one of its aspects a rinse cycle softener composition comprising A) an organic cationic compound which is substantive to water rinse on textile fibres, B) a silicone foam controlling agent, comprising a liquid polydiorganosiloxane and solid hydrophobic filler particles, and C) a nonionic or cationic surfactant, capable o emulsifying, at least to some extent, the silicone foam controlling agent.
As Component (A) of the composition of this invention there may be employed any organic cationic substance which is substantive to water rinse on textile fabrics and which is capable of imparting softness and/or lubricity to textile fabrics. A large number of such substances is known and includes quaternary ammonium compounds such as (a) alkylmethyl quaternary ammonium compounds having either one C18-C2~ alkyl chain or two C12-C30 alkyl chains, the long chain alkyl groups being most commonly those derived from hydrogenated tallow. Examples of such compounds are ditallowdimethyl ammonium chloride, ditallowdimethyl ammonium methyl sulphate, tallowtrimethyl ammonium chloride, dieicosyldimethyl ammonium chloride, tallowdi-methyl(3-tallowalkoxypropyl)ammonium chlorid~, ~itetra-decyldimethyl ammonium chloride, didodecyldiethyl ammoniumacetate and tallowtrimethyl ammonium acetate;
(b) amido a~koxylated quaternary ammonium compounds.
Quaternary compounds of this type can be prepared from fatty acids or triglycerides and an amine e.g. diethylene triamine. The product is then alkoxylated with ethylene oxide or propylene oxide and quaternised with dimethyl sulphate. Compounds of type (b) can be represented by the formula y 2y c O I O
MC~INCH2CH2 -N-CH2CH2NHC-M X
_ CH3 wherein M represent~ a fatty alkyl group typically C12 to C20, X represents for example Cl, Br or the methyl sulphate group, y is 2 or 3 and c is an integer;
(c) quaternised amido imidazolines. Compounds of this type can be obtained by heating the alkoxylated product of reacting an amine and a fatty acid or triglyceride as described for type (b) to effect ring closure to the imidazoline. This is then quaternised by reaction with e.g. dimethyl sulphate. An example of a type (c) compound is 2-heptadecyl-1-methyl-1-(2'-stearoyl amido-ethyl)-imidazolinium methyl sulphate;

(d) polyamine salts and polyalkylene imine salts e.g.
[ l~H25NH(CH3)-(CH2)3-NH2C12H25]++[Cl-]2' [Cl8H37NH(cH3)-(cH2)2-NH(c2H5)2] (CH3S04) 2 and a poly-ethylene iminium chloride having about 10 ethylene imine units;
(e) alkyl pyridinium salts e.g. cetyl pyridinium chloride.
The generally preferred organic cationic conditioning agents are those having long chain, fatty alkyl groups derived from tallow or hydrogenated tallow and the generally preferred class of softening agents are those of type (a), that is the alkylmethyl ammonium compounds.
Fabric conditioning agents which may be employed as component (A) of the compositions of this invention are well known substances and have been widely described in the technical literature, see for example J. Am. Oil Chemists Soc., January 1978 (Vol 55), pages 11~ - 121 and Chemistry and Industry, 5th July 1969, pages ~93 - 903.
Component (B) is a silicone foam controlling agent.
These agents are known compounds and are commercially available. Silicone foam controlling agents which are suitable for the present invention consist essentially of polydiorganosiloxane polymers and a solid particulate filler which has been rendered hydrophobic, preferably a silica ~iller. The polydiorganosiloxane is suitably subs-tantially linear and may have the average formulaR[(R2)SiO]XSiR3, where each R independently denotes an alkyl or an aryl group. Examples of such groups are methyl, ethyl, propyl, isobutyl and phenyl. PreEerred polydiorganosiloxanes are linear or substantially linear polydimethylsiloxanes. Pre~erably they have trimethylsilyl end-blocking units and a viscosity at 25C of 5 x 10 5 m2/s to 0.1 m2/s i.e. a value of x in the range 40 to 1500.
These are preferred because of their commercial , `
- ' ' . ` .. ,~ .

?~

availability, their relative low cost and their suitable surface energy. The solid filler consists preferably of silica particles. These may be fumed or precipitated silica particles or may be made by gel-formation techniques. The silica particles suitably have an average particle si~e of from 0.1 to 50 micron, preferably from 1 to 20 micron and a surface area of at least 50m2/g. These silica particles can be rendered hydrophobic e.g. by treating them with fatty acids, with dialkylsilyl groups and/or trialkylsilyl groups either bonded directly onto the silica, for example by reacting the silica with hydroxy-endblocked polydialkyl siloxanes, or by means of a silicone resin, having e.g. SiO2 and R'aSiO4 a units, wherein each R' is independently an alkyl, aryl or hydroxyl group, preferably methyl, and a has a value of 1 or 2 or prefer-ably 3. We prefer to employ a silica, the particles whereof have been rendered hydrophobic with dimethyl and/or trimethyl silyl groups. Silicone foam controlling agents, suitable for use in compositions according to the invention, have filler from 1 to 50%, preferably 2 to 30%
by weight of the total weight of the silicone foam controlling agent resulting in a compound having an average viscosity in the range of from 2 x 10-4 mZ/s to 1 m2/s.
Preferred silicone foam controlling compounds may have a viscosity of from 5 x 10 m2/s to 0.1 m2/s. The foam controlling compound may be present as a dispersion of the filler particles in the polydiorganosiloxane or they may be provided in the form of an oil-in-water emulsion.
Component (C) of a composition according to the invention is a nonionic or cationic surfactant, which is capable of emulsifying component (B) at least to some extent. Such surfactants include a range of materials, . ~ _ e.g. quaternary ammonium salts, amine oxides, alkylphenol ethoxylates, fatty or oxoalcohol polyethylene glycol ethers, eth-ylene oxide/propylene oxide polymers and fat-ty alcohol polyglycol ethers. Preferred surfactants are the nonionic surfactants which have a silicone portion and an oxyalkylene portion. The most preferred surfactants are siloxane oxyalkylene copolymers, having a siloxane chain, which has attached thereto one or more oxyalkylene groups, for example oxyethylene or oxypropylene groups or a mixture of both. The oxyalkylene groups are preferably linked to a silicon atom via an alkylene group. This alkylene group is for stability reasons preferably a propylene or isobutylene group, having three carbon atoms between the silicon atom and the oxyalkylene group. The remaining silicon-bonded substituents may be hydrocarbon groups having 1 to 18 carbon atoms, which may be substituted with e.g. trifluoro-propyl groups. Oxyalky]ene groups may be attached to each end of a linear siloxane chain, thus forming the copolymers of the ABA form, wherein A represents the oxyalkylene group and B represents the siloxane chain. Alternatively the oxyalkylene groups may be pending from the siloxane chain, thus forming the so-called rake co-polymers. The oxyalky-lene groups May be end-capped for example with an anion, e.g. acetate, or they may be left uncapped, thus termi-nating in a hydroxyl group.
Component (C) surfactants may be present as theemulsifier, or one of the emulsifiers, of the silicone foam controlling agent when component (B) is added to the composition of the invention as an emulsion. It is, however, preferred that they are separate from the silicone foam controlling agent, or additional to the emulsifier(s) of the foam controlling agent when the latter is provided as an emulsion.

gP41~'~

A composition according to the invention may comprise up to 50~ by weigh~ of component (A), preferably from 5 to 35%. Most preferred are those compositions which are regarded as concentrated fabric softeners, i.e. having from 12 to 30% of component (A). Component (B) may be present at 0.01 to 5% by weight of the total composition. It is preferred that from 0.05 to 1% is used. Higher levels are also effective but increasing the amount of foam controlling agent used does not tend to improve the control of foam any further. Levels below 0.1% will work, but to a lesser degree. The amount of component (C) used in the composition of the invention may range from sufficient to give a stable emulsion of the foam controlling agent, to an amount equal to about 10 times the amount of component (B) used. Preferably the ratio of component (B) to (C) is in the range from 1:1 to 1:5.
The compositions according to the invention may also comprise other ingredients, for example those which are conventional in softening compositions. These include water miscible solvents, perfume, dyes, thickeners, other emulsifiers, electrolytes, preservatives, optical brighteners etc. They may also include other organo-siloxane polymers, for example linear or cyclic polydi-organosiloxanes which may be present as e.g. as emulsions or as diluent for the preferred component (C). The ingredients may be mixed together in conventional ways using blenders or other homogenising equipment.
The invention also provides a method of softening textile materials by applying thereto a rinse cycle softener compo sition comprising a liquid rinse cycle softener composition comprising (A) an organic cationic compound which is substantive to water rinse on textile fibres, (B) a silicone foam controlling agent comprising a liquid .~

~. f~ t~ ~P ~l polydiorganosiloxane and solid hydrophobic filler particles and, (C) a nonionic or ca-tionic surfactant capable of emulsifying, at least to some extent, the silicone foam controlling agent.
There now follow a number of examples which illustrate the invention~
To a concentrated softener composition (3~1% solids by weight), which is believed to be based on ditallow or distearyl dlalkyl ammonium salts, was added 1% by weight of an emulsion containing 10% by weight of a silicone foam controlling agent consisting of 88 parts polydimethyl-siloxane having a viscosity of 1000 mm2/s and 12 parts of a hydrophobic silica. The emulsifiers used in the emulsion were glycerol monostearate and a monoester of polyethylene glycol to form a first example softener.
A second example softener was prepared by adding instead of the emulsion of the first example, 0.3% by weight of a mixture of 15 parts of the silicone foam controlling agent used in the first example, 15 parts of polydimethyl siloxane polymer and 70 parts of a surfactant which was a polydimethyl siloxane oxyalkylene copolymer having 10 mole ~ oxyethylene/oxypropylene units pending in the siloxane chain, and having a molecular weight of about 28000.
A third example softener was prepared by adding to the first example softener the copolymer of the second example softener in an amount giving a ratio of ~.5:1 to the silicone foam controlling agent.
All three example compositions were tested for their foam controlling ability. As a comparative test the softener used in the examples was also tested without the addition of components (B) and (C), according to the invention. 3.5kg of clean cotton was washed in a .
. , conventional front loading washing machine (Miele 433) by using lOOg of commercially available washing powder which has no silicone foam controlling agent in it. The washing cycle used was at 95C. At the fourth (last) rinsing cycle, 30g of the e~ample softener was added to the machine in the conventional way, and the foam height was measured during the rinse cycle. A comparison was also made with a blank run, using no softener addition in the rinse cycle.
Foam height is measured in % of the height of the window of the front loading machine which is covered by foam at the moment the drum is stationary. Results are given in the following table showing that compositions according to the invention control the foam of softener compositions satisfactorily.
TABLE
Test Sample ~ Foam Height Blank 40 Comparative 70 Example I 45 Example II35 Example III 35

Claims

1. A liquid rinse cycle softener composition comprising (A) an organic cationic compound which is substantive to water rinse on textile fibres, (B) a silicone foam controlling agent comprising a liquid polydiorganosiloxane and solid hydrophobic filler particles, and (C) a surfactant capable of emulsifying, at least to some extent, the silicone foam controlling agent (B) and which is selected from nonionic and cationic surfactants.

2. A liquid rinse cycle softener composition according to Claim 1 comprising up to 50% by weight of component (A) and from 0.01 to 5% by weight of component (B).

3. A liquid rinse cycle softener composition according to Claim 1 comprising from 5 to 35% by weight of component (A).

4. A liquid rinse cycle softener composition according to Claim 1 comprising from 12 to 30% by weight of component (A).

5. A liquid rinse cycle softener composition according to Claim 1 comprising from 0.05 to 1% by weight of component (B).

6. A liquid rinse cycle softener composition according to Claim 1 wherein the weight ratio of component (B) to component (C) is from 1/1 to 1/5.

7. A liquid rinse cycle softener composition according to Claim 1 wherein component (A) is a quaternary ammonium compound.

8. A liquid rinse cycle softener composition according to Claim 1 wherein component (B) consists essentially of a polydi-methylsiloxane having trimethylsilyl end- blocking units and having a viscosity at 25°C of from 5 x 10 5 to 0.1 m2/s and a silica filler which has been rendered hydrophobic.

9. A liquid rinse cycle softener composition according to Claim l wherein component (C) is a nonionic surfactant having a silicone portion and an oxyalkylene portion.

10. A liquid rinse cycle softener composition according to Claim 9 wherein the silicone portion is a siloxane portion and the oxyalkylene portion is linked to a silicon atom via an alkylene group.

11. A liquid rinse cycle softener composition according to Claim 10 wherein the alkylene portion is selected from the group consisting of propylene and isobutylene groups having 3 carbon atoms between the silicon atom and the oxyalkylene group.

12. A method of treating textile fabrics which comprises applying thereto a liquid rinse cycle softener composition comprising (A) an organic cationic compound which is substantive to water rinse on textile fibres, (B) a silicone foam controlling agent comprising a liquid polydiorganosiloxane and solid hydrophobic filler particles and, (C) a nonionic or cationic surfactant capable of emulsifying, at least to some extent, the silicone foam controlling agent.