Organosiloxane compositions

1. A method of making a linear diluted polysiloxane containing polymer comprising the steps of:

i) preparing a linear polysiloxane containing polymer by the polycondensation of siloxane containing oligomers which comprise condensable groups in the presence of an organic based extender or plasticiser, a suitable catalyst and an end-blocking agent; and

ii) where required quenching the polymerisation process;

wherein the organic based extender or plasticiser is substantially retained within the resulting linear diluted organopolysiloxane; and

wherein the organic based extender or plasticiser is selected from one or more of the group comprising

linear or branched mono unsaturated hydrocarbons; and

mineral oil fractions comprising linear (n-paraffinic) mineral oils, branched (iso-paraffinic) mineral oils, cyclic (naphthenic) mineral oils, and mixtures thereof.

2. A method in accordance with claim 1 wherein the polymerisation product has the general formula

X 3 -A-X 1

where X 3 and X 1 are independently selected from siloxane groups which terminate in hydroxyl or hydrolysable groups and A is a siloxane containing polymeric chain, said hydroxyl-terminating or hydrolysable groups X 3 or X 1 being selected from —Si(OH) 3 , —(R a )Si(OH) 2 , —(R a ) 2 SiOH, —R a Si(OR b ) 2 , —Si(OR b ) 3 , —R a 2 SiOR b or —R a 2 Si—R c —SiR d p (OR b ) 3-p where each R a independently represents a monovalent hydrocarbyl group; each R b and R d group is independently an alkyl or alkoxy group in which the alkyl groups suitably have up to 6 carbon atoms; R c is a divalent hydrocarbon group which may be interrupted by one or more siloxane spacers having up to 6 silicon atoms; and p has the value 0, 1 or 2.

3. A method in accordance with claim 1 wherein the polymerisation process is a polycondensation polymerisation process in which a linear and/or branched organopolysiloxane having hydrolysable terminal groups is polymerised in the presence of a condensation catalyst selected from

(i) a catalyst of the general formula R 20 SO 3 H in which R 20 represents an alkyl group, an aryl or an alkaryl group;

(ii) a phosphonitrile halide catalyst;

(iii) phosphonitrile halide ion based catalysts;

(iv) a titanate and/or zirconate;

(v) protic acids;

(vi) Lewis acids;

(vii) organic and inorganic bases;

(viii) borates; and

(ix) boranes.

4. A method in accordance with claim 3 wherein the catalyst is dodecylbenzenesulphonic acid quenched by a mono/di and trialkanolamine or an aluminasilicate zeolite.

5. A method in accordance with claim 1 wherein the extender or plasticiser is at least substantially miscible with the oligomer and the polymer.

6. A linear diluted organopolysiloxane polymer formed from the method in accordance with claim 1 .

7. A linear diluted organopolysiloxane polymer in accordance with claim 5 wherein the polymer has the general formula

X 3 -A-X 1

where X 3 and X 1 are independently selected from silyl groups which terminate in hydroxyl or hydrolysable groups selected from —Si(OH) 3 , —(R a )Si(OH) 2 , —(R a ) 2 SiOH, —R a Si(OR b ) 2 , —Si(OR b ) 3 , —R a 2 SiOR b and —R a 2 Si—R c —SiR d p (OR b ) 3-p where each R a independently represents a monovalent hydrocarbyl group, each R b and R d group is independently an alkyl or alkoxy group in which the alkyl groups suitably have up to 6 carbon atoms; R c is a divalent hydrocarbon group which may be interrupted by one or more siloxane spacers having up to 6 silicon atoms; and p has the value 0, 1 or 2; and A is a siloxane containing molecular chain.

8. A method of making a moisture curable composition capable of cure to an elastomeric body comprising the steps of forming the linear diluted organopolysiloxane polymer in accordance with the steps of claim 1 and mixing the linear diluted organopolysiloxane polymer with a suitable cross-linking agent which is reactive with the linear organopolysiloxane polymer, a suitable condensation catalyst and optionally filler.

9. A method of making a moisture curable composition capable of cure to an elastomeric body in accordance with claim 8 wherein the cross-linking agent is one or more silane or siloxane which contain acyloxy groups and/or ketoximino groups, and the catalyst is a tin catalyst.

10. A method of making a moisture curable composition capable of cure to an elastomeric body in accordance with claim 8 wherein the cross-linking agent is one or more silane or siloxane which contain alkoxy groups and alkenyloxy groups, and the catalyst is a titanate or zirconate or a chelated titanate or chelated zirconate.

11. A method of making a moisture curable composition capable of cure to an elastomeric body in accordance with claim 8 wherein the filler comprises one or more finely divided, reinforcing fillers selected from the group of high surface area fumed silica, precipitated silica, and calcium carbonate, and/or one or more extending fillers selected from the group of crushed quartz, diatomaceous earth, barium sulphate, iron oxide, titanium dioxide, carbon black, talc, and wollastonite.

12. A composition comprising a diluted organopolysiloxane formed from the method of claim 1 wherein the organic based extender or plasticiser is added to the composition immediately after the polycondensation reaction has commenced or sequentially during polymerisation, and wherein the organic based extender or plasticiser is substantially retained within the linear diluted organopolysiloxane.

13. A method of making a silicone rubber composition comprising the steps of:

preparing a linear diluted organopolysiloxane containing polymer in accordance with the method of claim 1 optionally containing an alkenyl group, a condensable group, a silyl-hydride or trimethylsilyl containing end-blocker, and a siloxane based extender or plasticiser; and

compounding the resulting linear diluted organopolysiloxane polymer with one or more reinforcing and/or non reinforcing fillers and a curing agent; and optional additives selected from the group of one or more rheology modifiers, pigments, colouring agents, anti-adhesive agents, adhesion promoters, blowing agents, fire retardants and dessicants,

wherein the organic based extender or plasticiser is substantially retained within the linear diluted organopolysiloxane.

14. A method in accordance with claim 13 wherein the curing agent is one or more organic peroxides selected from the group of dialkyl peroxides, diphenyl peroxides, benzoyl peroxide, 1,4-dichlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, tertiary butyl-perbenzoate, monochlorobenzoyl peroxide, ditertiary-butyl peroxide, 2,5-bis-(tertiarybutyl-peroxy)-2,5-dimethylhexane, tertiary-butyl-trimethyl peroxide, tertiary-butyl-tertiary-butyl-tertiary-triphenyl peroxide, and t-butyl perbenzoate.

15. A method in accordance with claim 13 wherein the polymer comprises unsaturated groups and the curing agent is a hydrosilylation reaction catalyst in combination with an organohydrogensiloxane.

16. A method in accordance with claim 15 wherein the organohydrogensiloxane comprises from 4-20 silicon atoms per molecule, and has a viscosity of up to about 10 Pa·s at 25° C.

17. A method in accordance with claim 15 wherein the hydrosilylation catalyst is a platinum group metal based catalyst selected from a platinum, rhodium, iridium, palladium or ruthenium catalyst.

18. A moisture curable composition capable of cure to an elastomeric body, the composition comprising:

a. a linear organopolysiloxane having not less than two silicon-bonded hydroxyl or hydrolysable groups that is diluted in an organic based extender or plasticiser;

b. a siloxane and/or silane cross-linker having at least two groups per molecule which are reactable with the hydroxyl or hydrolysable groups in the diluted organopolysiloxane;

c. one or more fillers; and

d. a suitable cure catalyst,

wherein the organic based extender or plasticiser is substantially retained within the linear diluted organopolysiloxane and is selected from the group comprising

linear or branched mono unsaturated hydrocarbons; and

mineral oil fractions comprising linear (n-paraffinic) mineral oils, branched (iso-paraffinic) mineral oils, cyclic (naphthenic) mineral oils, and mixtures thereof.

19. A composition in accordance with claim 18 additionally comprising one or more surfactants, detergents, thickeners, perfumes, colorants, electrolytes, pH control ingredients, foam boosters and foam stabilizers, antimicrobials, antioxidants, ultraviolet light absorbers and medicaments dyes, reducing agents, neutralizing agents, and preservatives.

20. A method of making a linear diluted polysiloxane containing polymer comprising the steps of:

i) preparing a linear polysiloxane containing polymer by the polycondensation of siloxane containing oligomers which comprise condensable groups in the presence of an organic based extender or plasticiser, a suitable catalyst and optionally an end-blocking agent; and

ii) where required quenching the polymerisation process;

wherein the organic based extender or plasticiser is substantially retained within the resulting linear diluted organopolysiloxane; and

wherein the organic based extender or plasticiser is selected from one or more of the group of

polyisobutylenes (PIB),

phosphate esters, polyalkylbenzenes, and

linear and/or branched alkylbenzenes esters of aliphatic monocarboxylic acids.

21. A method in accordance with claim 20 wherein the polymerisation product has the general formula

X 3 -A-X 1

where X 3 and X 1 are independently selected from siloxane groups which terminate in hydroxyl or hydrolysable groups and A is a siloxane containing polymeric chain, said hydroxyl-terminating or hydrolysable groups X 3 or X 1 being selected from —Si(OH) 3 , —(R a )Si(OH) 2 , —(R a ) 2 SiOH, —R a Si(OR b ) 2 , —Si(OR b ) 3 , —R a 2 SiOR b or —R a 2 Si—R c —SiR d p (OR b ) 3-p where each R a independently represents a monovalent hydrocarbyl group; each R b and R d group is independently an alkyl or alkoxy group in which the alkyl groups suitably have up to 6 carbon atoms; R c is a divalent hydrocarbon group which may be interrupted by one or more siloxane spacers having up to 6 silicon atoms; and p has the value 0, 1 or 2.

22. A method in accordance with claim 20 wherein the polymerisation process is a polycondensation polymerisation process in which a linear and/or branched organopolysiloxane having hydrolysable terminal groups is polymerised in the presence of a condensation catalyst selected from

(i) a catalyst of the general formula R 20 SO 3 H in which R 20 represents an alkyl group, an aryl or an alkaryl group;

(ii) a phosphonitrile halide catalyst;

(iii) phosphonitrile halide ion based catalysts;

(iv) a titanate and/or zirconate;

(v) protic acids;

(vi) Lewis acids;

(vii) organic and inorganic bases;

(viii) borates; and

(ix) boranes.

23. A method in accordance with claim 22 wherein the catalyst is dodecylbenzenesulphonic acid quenched by a mono/di and trialkanolamine or an aluminasilicate zeolite.

24. A method of making a linear diluted polysiloxane containing polymer comprising the steps of:

i) preparing a linear polysiloxane containing polymer by the polycondensation of siloxane containing oligomers which comprise condensable groups in the presence of an organic based extender or plasticiser, a condensation catalyst selected from

a catalyst of the general formula R 20 SO 3 H in which R 20 represents an alkyl group, an aryl or an alkaryl group;

a phosphonitrile halide catalyst; and

a phosphonitrile halide ion based catalyst, and optionally an end-blocking agent; and

ii) where required quenching the polymerisation process;

wherein the organic based extender or plasticiser is substantially retained within the resulting linear diluted organopolysiloxane; and

wherein the organic based extender or plasticiser is selected from one or more of the group comprising

linear or branched mono unsaturated hydrocarbons; and

mineral oil fractions comprising linear (n-paraffinic) mineral oils, branched (iso-paraffinic) mineral oils, cyclic (naphthenic) mineral oils, and mixtures thereof.

25. A method as set forth in claim 24 wherein the condensation catalyst is further defined as dodecylbenzenesulphonic acid.

26. A method as set forth in claim 25 wherein the dodecylbenzenesulphonic acid is quenched by a mono/di and trialkanolamine or an aluminasilicate zeolite.

27. A moisture curable composition capable of cure to an elastomeric body, the composition comprising:

a. a linear organopolysiloxane having not less than two silicon-bonded hydroxyl or hydrolysable groups that is diluted in an organic based extender or plasticiser and that is formed in accordance with the method of claim 1 ;

b. a siloxane and/or silane cross-linker having at least two groups per molecule which are reactable with the hydroxyl or hydrolysable groups in the diluted organopolysiloxane;

c. one or more fillers; and

d. a suitable cure catalyst,

wherein the organic based extender or plasticiser is substantially retained within the linear diluted organopolysiloxane and is selected from the group comprising

linear or branched mono unsaturated hydrocarbons; and

mineral oil fractions comprising linear (n-paraffinic) mineral oils, branched (iso-paraffinic) mineral oils, cyclic (naphthenic) mineral oils, and mixtures thereof.