GB2223768A

GB2223768A - Softening compositions

Info

Publication number: GB2223768A
Application number: GB8919257A
Authority: GB
Inventors: Annemieke Constantia M Donkers; Julie Hughes Sheppard
Original assignee: Dow Corning Ltd; Dow Corning Corp
Current assignee: Dow Silicones UK Ltd; Dow Silicones Corp
Priority date: 1988-10-12
Filing date: 1989-08-24
Publication date: 1990-04-18
Anticipated expiration: 2009-08-24
Also published as: GB8823875D0; DE3933971C2; GB8919257D0; DE3933971A1; GB2223768B; FR2637620A1; FR2637620B1; CA2000481A1

Description

2 '. 2," 3 7' 6 8 SOFTENING COMPOSITIONS The present invention relates to

softening compositions, 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 d4(C 1_ c 5) 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 SpecifLcation are claimed to provide easier ironing, anti-static properties, pleasanter feel of the fabrics and soil release properties.

Detergent 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 the 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 provi:ded 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 only requiring 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 formulation as a consequence of concentrating the softener compositions, there is an inherent foam problem with some of these compositions when they are introduced in the rinse the washing process. It is regarded as aestheti- cycle o 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 softeuer 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 1 r 0 depressor is described as a polysiloxane containing moieties of the general structure -(R'R"SiO).-, wherein x has a value of from 20 to about 2000 and R' and W' 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 composition will be released, at least in part, from the first rinse cycle onwards. Liquid rinse cycle softeners also require a different solution to the problem of controlling f o air..

We have now found that improved rinse.eycle softener compositions can be produced by introducing int o them a silicone foam controlling agent, comprising a polydiorganosiloxane and hydrophobic solid particles, and a nonionic or cationic surfactant 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) C) 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 a nonionic or cationic surfactant, capable of emulsifying, at least to some extent, the silicone foam controlling agent.

As Component (A) of the composition of this invention 30, 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 such substances is textile fabrics. A large number oi 1 kno-v,,n and includes quaternary ammonium compounds such as (a.) alkylmethyl quaternary ammonium compounds havingeither one C 18- C 24 alkyl chain or two C 12- C 30 alkyl chains, the long chain alkyl groups being most commonly those derived 5 from hydrogenated tallow. Examples of puch compounds are ditallowdimethyl ammonium chloride, ditallowdimethyl ammonium methyl sulphate, tallowtrimethyl ammonium chloride, dieicosyldimethyl ammonium chloride, tallowdimethyl(3tallowalkoxypropyl)ammonium chloride, ditetra- decyldimethyl ammonium chloride, didodecyldiethyl ammonium acetate and tallowtrimethyl ammonium acetate; (b) amido alkoxylated quaternary ammonium compounds. Quaternary compounds of this ty e can be prepared from 1 p fatty acids or triglycerides and an amine e.g. diethyli-ene 1-51 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 f ormula T_ i (C H 0) H + y 2yc 0 0 11 1 il -- MICHNCH CH,-N-CHCH,NHC-M 2 CH 3 wherein M represents a fatty alkyl group typically C L. J_ 12 to c 201 7, represents for example Cl, Br or the methyl. sulphate group, X 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-l-methyl-l- (d'-'-stearoyl amido-ethyl)imidazolinium methyl sulphate; z (d) polyamine salts and polyalkylene imine salts e.g. [C 12 H 25 NH(CH 3)- (CH 2) 3-NH 2 c 12 H 25] ++ [Cl - 1 21 [C18H 37 NH(CH 3)-(CH,)) 2- NH(C2H5)2] ++ (CH3S04)-2 and a polyethylene iminium chloride having about 10 ethylene imine 5 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 118 - 121 and Chemistry and Industry, Sth July 1969, pages 893 - 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 filler. The polydiorganosiloxane is suitably substantially linear and may have the average formula R[(R 2)Siol X SiR 31 where each R independently denotes an alkyl or an aryl group. Examples of such groups are methyl, ethyl, propyl, isobutyl and phenyl. Preferred polydiorganosiloxanes are linear or substantially linear polydimethylsiloxanes. Preferably they have trimethylsilyl end-blocking units and a viscosity at 25'C 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 costan&their suitable surface energy. The solid f41 ller consists preferably of silica particles. These may be fumed or precipitated silica particles or may be made by ge]--formation techniques. The silica particles suitably have an average particle size 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. SiO 2 and R' a Sio 4-a units, wherein 2--- each R' is independently an alkyl, aryl or hydroxyl group, preferably methyl, and a has a value of 1 or 2 or preferably 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 21 x 10- 4 M2/S to 1 M2/S.

Preferred silicone foam controlling compounds may have a viscosity of from 5 x 10- 3 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, 7 e.g. quaternary ammonium salts, amine oxides, alkylphenol ethoxylates, fatty or oxoalcohol polyethylene glycol ethers, ethylene oxide/propylene oxide polymers and fatty 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 prelerably 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 I to 16 carbon atoms, which may be substituted with e.g. tri'Lluoropropyl groups. Oxyalkylene 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 s.Lioxane chain, thus forming the so-called rake co-polymers. The oxyalkylene groups may be end-capped for example WL-,-h an anion, e.g. acetate, or they may be left uncapped, thus term-,nating in a hydroxyl group.

Component (C) surfactants may be present as the emulsifier, 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.

A composition according to-.the invent-L-On may connr-,-se up to 501by weight of component (A), preferably from 5 to 351%. 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 17 component (B) amount equal to about 10 times the amount o t_ 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 organosiloxane polymers, for example linear or cyclic polydiorganosiloxanes 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 1 C, 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. 5 There now follow a number of examples which illustrate the invention. To a concentrated softener composition (34%. solids by weight), which is believed to be based on ditallow or distearyl dialkyl ammonium salts, was added 1% by weight of an emulsion containing 10/10 by weight of a silicone foam controlling agent consisting of 88 parts polydimethylsiloxane having a viscosity of 1000 Mrr,2/s and 12 parts of a hydrophobic silica. The emulsifiers used ir. 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, 0.3l.' by weight of a mixture of 15 parts of the silicone foam controlling agent used in the first example, 15 parts off a surfactant polydimethyl siloxane polymer and 70 parts o which was a polyd4j-lTLethyl siloxane oxyalkylene copolymer having 10 mole % oxyethylene/oxypropylene un.-,.ts 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 4.5:1 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 wj-thout the addition of components (B) and (C), according to the invention. 3.5kg of clean cotton was washed in a 1 - 10.

conventional front loadingwashing-machine (Miele 43-1.) by using 100g of commercially available washing powder which has no silicone foam controlling agent in it. The washing cycle used was at 95'C. At the fourth (last) rinsing cycle, 30g of the example 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 Blank Comparative Example T Example II Example III i % Foam Height 40 70 45 35 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 nonionic or cationic surfactant capable of emulsifying, at least to some extent, the silicone foam controlling agent.

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 oil component (B).

3. A liquid rinse cycle softener composition according to any one of the preceding clainis comprising from 12 to 301% by weight of component (A).

4. A liquid rinse cycle softener composition according to any one or' the preceding claims comprising from 12 to 30% by weight of component (A).

5. A liquid rinse cycle softener composition according to any one of the preceding claims comprising from 0.05 to 1% by weight of component (B).

6. A liquid rinse cycle softener composition according to any one of the preceding claims 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 any one of the preceding claims wherein component (A) is a quaternary ammonium compound.

i

8. A-liquid r-inse- cycle softene-r-composition-according to any, one of the preceding claims wherein component.-(B) consists essentially of a polydimethylsiloxane having trimethylsilyl endblocking 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 any one of the preceding claims wherein component (C) is a nonionic surfactant having a silicone portion and an oxyalkylene group.

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 group is a propylene or isobutylene group having 3 carbon atoms between the silicon atoir. 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.

Published 1990 at The Patent Office, State House, 66'71 High Holborn, London WCIR 4TP. Further copies maybe obtained from The Patent OfficeSales Branch, St Maxy Cray, Orpington. Kent BR5 311D. Printed by Multiplex techniques ltd, St Mary Cray. Kent. Con. 1'87 i