GB2036052A

GB2036052A - Organosilicon Polymers

Info

Publication number: GB2036052A
Application number: GB7937383A
Authority: GB
Original assignee: Dow Corning Ltd
Current assignee: Dow Silicones UK Ltd
Priority date: 1978-11-08
Filing date: 1979-10-29
Publication date: 1980-06-25
Also published as: IT7927102A0; GB2036052B; AU528039B2; FR2440961B1; JPS586731B2; CA1134986A; IT1165361B; DE2942786C2; ZA795749B; DE2942786A1; JPS5566928A; FR2440961A1; AU5252779A

Abstract

A polydiorganosiloxane containing amino-substituted organic groups is prepared by reacting a silanol-terminated polydiorganosiloxane, in which at least 50 per cent of the total silicon- bonded organic substituents are methyl groups, with a silane CH3(XO)2SiZ in which X represents alkyl or alkoxyalkyl and Z represents a monovalent group composed of carbon, hydrogen, nitrogen and optionally oxygen and which contains at least two amine groups, (A) and (B) being reacted in a proportion of from 1.75 to 3.5 moles of (B) per mole of (A). The polydiorganosiloxanes are mixed with alkylhydrogen- polysiloxanes and the compositions employed for the treatment of textiles.

Description

SPECIFICATION Organosilicon Polymers This invention relates to organosilicon polymers, to compositions prepared from said polymers and to the use of the said compositions for the treatment of textiles.

In German OLS 2 621 460 there are disclosed compositions for the treatment of wool to render it shrink resistant, the said compositions comprising (A) a polydiorganosiloxane having terminal OX radicals, in which X represents hydrogen, alkyl or alkoxyalkyl, and also having silicon-bonded substituents which contain at least two amino groups, and (B) an organosiloxane having at least three silicon-bonded hydrogen atoms in the molecule. The preferred polydiorganosiloxanes (A) are those which are prepared by reacting a silanol-terminated polydiorganosiloxane which is free of the specified amino-containing substituents with a silane CH3(XO)2SiZ, in which Z represents a monovalent radical containing at least two amino groups.A polydiorganosiloxane of this type which is specifically described in the German OLS is that obtained by reacting the silanol terminated polymer with 0.75% by weight of the silane. However, although such a polydiorganosiloxane functions satisfactorily as a component of the shrinkproofing compositions it has been found that the viscosity of such polymers tends to increase during storage. This viscosity change constitutes a significant manufacturing inconvenience especially when it is desired to store or ship the polydiorganosiloxane prior to subjecting it to emulsification.

According to this invention we have now found that amino-substituted polydiorganosiloxanes having improved stability of viscosity during storage can be obtained if the silane and polydiorganosiloxane reactants are brought together in certain molar proportions.

Accordingly this invention provides a process for the preparation of a polydiorganosiloxane which comprises reacting together (A) a silanol-terminated polydiorganosiloxane having a molecular weight of at least 1 0,000 and wherein at least 50 per cent of the total silicon-bonded organic substituents are methyl groups, any remaining organic substituents being monovalent hydrocarbon groups having from 2 to 20 carbon atoms, and (B) a silane of the general formula CH3(XO)2SiZ wherein X represents an alkyl or alkoxyalkyl group having up to 5 carbon atoms and Z represents a monovalent group composed of carbon, hydrogen, nitrogen and, optionally, oxygen, the said group containing at least two amine groups and being attached to silicon through a silicon to carbon linkage, (A) and (B) being reacted in a proportion from 1.75 to 3.5 moles of (B) per mole of (A).

The polydiorganosiloxanes (A) employed in the preparation of the copolymers of this invention are those having a hydroxyl group attached to each terminal silicon atom and a molecular weight of at least 10,000. At least 50 per cent of the total silicon-bonded substituents in the polydiorganosiloxane should be methyl groups, any remaining substituents being monovalent hydrocarbon radicals having from 2 to 20 carbon atoms, for example ethyl, propyl, 2,4,4-trimethylpentyl, cyclohexyl, vinyl and phenyl. Preferably the polydiorganosiloxanes are polydimethylsiloxanes, those having molecular weights in the range from 20,000 to 60,000 (that is, having viscosities from about 1000 to 1 0,000 cS at 250C) being most preferred.

In the general formula of the silanes (B) X may represent an alkyl group having from 1 to 5 carbon atoms or an alkoxyalkyl group having up to 5 carbon atoms, each X preferably representing methyl or ethyl. The group Z may be for example -(CH2)NHCH2CH2NHCH2CH2NH2,

or -(CH2)3NH(CH2)2NHCH2C0OCH3, but is preferably selected from -(CH2)3NHCH2CH2NH2, -(CH2)4NHCH2CH2NH2 or CH2CH(CH3)CH2NHCH2CH2NH2.

Reaction between (A) and (B) can be brought about by mixing the two at room temperature. It is preferred, however, to expedite the reaction by heating a mixture of (A) and (B) at a temperature of from 60 to 1 600C for a period of from 30 minutes to 3 hours. A catalyst for the reaction between =-SiOX groups may be employed if desired but the reaction usually proceeds at a satisfactory rate in the absence of a catalyst. At least 1.75 moles of the silane (B) are employed per mole of (A), the preferred range being from 1.95 to 2.5 moles of (B) per mole of (A).

The polymers prepared according to the process of this invention can be employed in the manner described in German OLS 2/621 460 to provide compositions for the treatment of keratinous fibres, e.g. wool, to render such fibres shrink resistant. They may also be employed as described in German OLS 2 728 597 in the preparation of compositions which can be applied to cellulosic and synthetic fibres, e.g. nylon, polyester and polyester-cotton blends, to impart thereto resilience and/or crease resistance. According to a further aspect of this invention, therefore, there are provided compositions comprising (i) a polydiorganosiloxane prepared by the process of this invention and (ii) an organosiloxane having at least three silicon-bonded hydrogen atoms in the molecule and in which the organic substituents are alkyl groups having less than 1 9 carbon atoms.Such compositions, in the form of solutions in organic solvents, or, more preferably, as aqueous emulsions, may be applied to a variety of textiles to impart thereto certain desirable properties. For example they may be applied to keratinous fibres, particularly woollen garments, to impart thereto a significant resistance to shrinkage during laundering. When there is added to the compositions comprising (i) and (ii) a siloxane curing catalyst (iii) the resulting compositions are particularly suitable for the treatment of cellulosic and/or synthetic fibres to impart resilience and/or resistance to creasing. A wide variety of siloxane curing catalysts are known including acids, bases and organic metal compounds.The preferred catalysts are metal carboxylates e.g. lead 2-ethylhexoate, zinc naphthenate, stannous octoate, dibutyltin dioctoate, di-n-octyltin diacetate, dibutyltin di(iso-octylthioglycollate), diorganotin alkoxides e.g. dibutyltin diethoxide and dioctyltin dimethoxide, and titanium alkoxides e.g. butyl titanate, octylene glycol titanate and triethanolamine titanate. The most preferred catalysts are the organic tin compounds.

The organosiloxanes which comprise component (ii) of the compositions of this invention are, in general, well-known materials. They may comprise any one or more organosiloxanes having at least three silicon-bonded hydrogen atoms in the molecule. They are preferably linear siloxane polymers but may if desired be cyclic or branched. The organic substituents present in the organosiloxane are preferably methyl groups but other alkyl radicals having less than 1 9 carbon atoms e.g. ethyl or 2,4,4trimethylpentyl may also be present. The organosiloxane may be, for example, a copolymer of dimethylsiloxane units, methylhydrogensiloxane units and trimethylsiloxane units or more preferably a trimethylsiloxy-terminated poly(methylhydrogen siloxane).

The relative proportions of (i) and (ii) employed to prepare the treating compositions according to this invention are not critical. Up to about 20 per cent or more of (ii) based on the weight of (i) may be used. However, it is generally preferred that the siloxane (ii) be employed in a proportion of from 0.5 to 10 per cent by weight based on the weight of polydiorganosiloxane (i). When the catalyst (iii) is incorporated in the treating compositions it is preferably employed in a proportion of from 0.25 to 10 per cent by weight based on the total weight of (i) and (ii).

When the compositions are applied as an organic solvent solution any appropriate volatile solvent may be employed as the carrier, for example toluene, xylene, white spirit or perchloroethylene. Any suitable emulsifying agent may be employed to prepare the aqueous emulsion treating compositions.

The preferred emulsifying agents are those of the non-ionic or cationic types, for example the polyethoxy ethers of nonyl phenol and octyl phenol, the trimethylnonyl ethers of polyethylene glycols, monoesters of alcohols and fatty acids, e.g. glyceryl monostearate, and ethoxylated amines.

Application of the compositions to textiles can be carried out using conventional techniques such as padding, dipping and spraying. Drying of the treated fibres and cure of the siloxane composition can be allowed to occur by exposure to normal ambient temperatures, that is from about 1 5 to 250C, for periods of up to 4 days or more. In general, however, it is preferred to expedite the drying and/or curing steps by exposure of the treated fibres to elevated temperatures, preferably from 50 to 1 700 C.

The following Examples, in which the parts are expressed by weight, illustrate the invention.

Example 1 The silane CH3(CH3O)2Si(CH2)3NHCH2CH2NH2 (14 parts) (2 mol) and a polydimethylsiloxane (1000 parts) (1 mol) having a hydroxyl group attached to each terminal silicon atom and a viscosity of approximately 4500 cS at 250C (mol.wt. approximately 46000) were mixed together in a reaction vessel fitted with a stirrer and nitrogen purge. The reaction mixture was then heated to 1 350C with stirring and under nitrogen for 1.5 hours. The product was a siloxane polymer (Polymer A) having a viscosity of approximately 6,500 cS at 250C.

A portion of this polymer was stored at 220C and its viscosity measured periodically during 6 months. For comparison, similar viscosity measurements were also performed on a siloxane polymer (Polymer B) which had been prepared by an identicai procedure except that the silane was employed in a proportion of 1.25 moles per mole of the polydimethylsiloxane. This polymer had an initial viscosity of approximately 7,000 cS at 250C.The results obtained were as follows:

Slloxane Viscosity (cS at 250C) Initial 2 months 4 months 6 months Polymer A 6,500 9,000 13,000 20,000 Polymer B 7,000 13,000 29,000 1 52,000 Polymer A (33.3 parts), as prepared prior to storage was added gradually to a mixture of 3.33 parts of a nonionic emulsifier (Tergitol TMN-6) and water (7.30 parts). This mixture was stirred for one hour, passed through a colliod mill and then diluted with water (56.0 parts) to yield an aqueous emulsion (Emulsion X).

Employing a similar procedure an aqueous emulsion (Emulsion Yj of a trimethylsiloxy-terminated polymethyl-hydrogen siloxane (viscosity 30 cS at 25"C) was prepared from 33.3 parts of the siloxane, 0.86 parts of an ethoxylated fatty amine emulsifying agent, 1.65 parts of Tergitol TMN and 63.5 parts of water.

Emulsion X (4.6 parts) and Emulsion Y (0.06 part) were mixed with 2040 parts of water in which had been dissolved 10.2 parts of sodium sulphate and 1.0 part of 50% aqueous acetic acid. A piece of botany wool fabric (60 g.) was immersed in the resulting liquor, the temperature of the liquor raised to 400C and the wool agitated therein. After about 30 minutes the liquor had becomes clear, indicating deposition of the siloxane on the fabric. The fabric was then removed, dried at 800C for about 6 minutes and exposed to the ambient atmosphere (60% RH, 20"C) for 3 days.

The resistance of the treated sample to shrinkage was measured according to the method of the International Wool Secretariat, Specification WSS 128, Test Method 1 85 employing a laundering period of one hour. The sample exhibited a shrinkage of only 0.3%.

Example 2 Emulsion X and Emulsion Y, both as described in Example 1, were employed to treat nylon fabric according to the following procedure. Emulsion X (3 parts). Emulsion Y (0.5 part), a 20% by weight aqueous emulsion of dibutyltin di(iso-octylthioglycollate) (0.1 part) and an aqueous solution (0.1 part) containing triethanolamine titanate (50% by weight) and zinc acetate (11 % by weight), were added separately with stirring to 2000 parts of water.

A piece of nylon fabric (100 g.) was immersed in the aqueous liquor prepared as described above, the mixture being maintained at 250C. After about 30 minutes the treating liquor had become clear indicating deposition of the siloxane on to the fabric. The fabric was then removed from the treating bath, dried at 1 000C and placed in an oven at 1 500C for 3 minutes to cure the siloxane. When the crease recovery angle of the fabric was measured according to British Standard Specification 3086 a value of 1 560 was obtained. The value for the untreated fabric was 1100.

Example 3 Employing the procedure of Example 1 the silane CH3(CH3O)2Si(CH2)3NHCH2CH2NH2 (15.4 parts) (2.2 mol.) was reacted with a silanol terminated polydimethylsiloxane having a viscosity of approximately 4,000 cS at 250C. The product was a siloxane polymer (Polymer C) having a viscosity of 6,450 cS at 250C.

The polymer was stored at normal ambient temperature in a sealed container and its viscosity measured at intervals over a period of several months. For comparison, similar viscosity measurements were performed on a siloxane polymer (Polymer D) which had been prepared by an identical procedure but using 1.25 moles of silane per mole of polydimethylsiloxane. The results obtained were as follows:

Siloxane Viscosity (cS. at 25 OCj /nitial After 2 months After 5 months Polymer C 6,450 8,200 Polymer 7,600 7,600 19,800 Example 4 A siloxane polymer was prepared as described in Example 1 except that the quantity of the silane employed was increased from 14 to 21 parts.

8.7 parts of this siloxane polymer and 0.11 parts of a trimethylsiloxy end-stopped methylhydrogen polysiloxane were dissolved in 750 parts of perchloroethylene and the resulting solution employed to treat pieces of knitted Shetland wool fabric (cover factor 0.85) by padding, the add-on of siloxane being 3% by weight based on the weight of the wool. The wool pieces were dried at 800 C, subjected to further heating at 800C for 1 5 minutes to cure the siloxane and stored for 3 days prior to testing.

When the shrinkage of the fabric during laundering was measured as described in Example 1 a value of -1.2% was obtained after a one hour wash and -0.5 after a 3 hour wash.

Claims

1. A process for the preparation of a polydiorganosiloxane which comprises reacting together (A) a silanol-terminated polydiorganosiloxane having a molecular weight of at least 10,000 and wherein at least 50 per cent of the total silicon-bonded organic substituents are methyl groups, any remaining organic substituents being monovalent hydrocarbon groups having from 2 to 20 carbon atoms, and (B) a silane of the general formula CH3(XO)2SiZ wherein X represents an alkyl or an alkoxyalkyl group having up to 5 carbon atoms and Z represents a monovalent group composed of carbon, hydrogen, nitrogen and optionally oxygen, the said group containing at least two amine groups and being attached to silicon through a silicon to carbon linkage, (A) and (B) being reacted in a proportion of from 1.75 to 3.5 moles of (B) per mole of (A).

2. A process as claimed in Claim 1 wherein the polydiorganosiloxane (A) has a molecular weight in the range from 20,000 to 60,000.

3. A process as claimed in Claim 1 or Claim 2 wherein (A) is a polydimethylsiloxane.

4. A process as claimed in any one of the preceding claims wherein X is selected from methyl groups and ethyl groups.

5. A process as claimed in any one of the preceding claims wherein Z represents -(CH2)3NHCH2CH2NH2, (CH2)4NHCH2CH2NHz or -CH2CH(CH3)CH2NHCH2CH2NH2.

6. A process for preparing a polydiorganosiloxane as claimed in Claim 1 substantially as described in the Examples herein.

7. A polydiorganosiloxane whenever prepared by the process claimed in any one of the preceding claims.

8. A composition comprising (i) a polydiorganosiloxane as claimed in Claim 7 and (ii) an organosiloxane having at least three silicon-bonded hydrogen atoms in the molecule and in which the organic substituents are alkyl groups having less than 1 9 carbon atoms.

9. A composition as claimed in Claim 8 wherein (ii) is present in a proportion of from 0.5 to 10 per cent by weight based on the weight of (i).

10. A composition as claimed in Claim 8 or Claim 9 when in the form of an aqueous emulsion.

11. A composition as claimed in any one of Claims 8 to 10 inclusive wherein the alkyl groups in (ii) are methyl groups.

12. A composition as claimed in any one of Claims 8 to 11 inclusive which also contains a siloxane curing catalyst.

13. A process for treating textiles which comprises applying thereto a composition as claimed in any one of Claims 8 to 12 inclusive and thereafter curing the applied composition.

14. Textiles whenever treated by the process claimed in Claim 1 2.