Organosiloxane compositions

1. A curable phenylorganosiloxane polymer composition comprising:

(a) 100 parts by weight of a phenylorganosiloxane having a viscosity of at least 10000 mPa·s at 25° C. and at least two reactive groups per molecule selected from

—OH or hydrolysable groups;

(c) 0 to 500 parts by weight of fillers per 100 parts by weight of (a);

(d) a suitable cure package comprising a cross-linker and a catalyst the suitable cure package being selected from

a silane having at least three silicon-bonded hydrolysable groups per molecule or polyorganosiloxane having at least three silicon-bonded hydrolysable groups per molecule and a condensation catalyst; and

(b) 0.1 to 300 parts by weight of at least one phenyl siloxane resin per 100 parts by weight of (a) in which

resin (b) is un-reactive with the cross-linker in cure package (d) or has at least two —OH groups or hydrolysable groups;

wherein resin (b) is selected from T resins in which a majority of the siloxane units are T units.

2. The phenylorganosiloxane polymer composition in accordance with claim 1 , wherein filler (c) comprises one or more finely divided, reinforcing fillers selected from high surface area fumed and precipitated silicas, calcium carbonate and/or one or more finely divided, semi-reinforcing or non-reinforcing fillers selected from crushed quartz, diatomaceous earths, barium sulphate, iron oxide, titanium dioxide and carbon black, talc, wollastonite, aluminite, calcium sulphate (anhydrite), gypsum, calcium sulphate, magnesium carbonate, clays aluminium trihydroxide, magnesium hydroxide, graphite, copper carbonate, nickel carbonate, barium carbonate, strontium carbonate, aluminium oxide, and silicates selected from the group consisting of olivine group, garnet group, aluminosilicates, ring silicates, chain silicates, and sheet silicates.

3. The phenylorganosiloxane polymer composition in accordance with claim 2 , wherein:

i) the cross-linker in cure package (d) is selected from one or more of a disilaalkane, alkyltrialkoxysilane, alkenyltrialkoxy silane, phenyltrimethoxysilane, alkoxytrioximosilane, alkenyltrioximosilane, 3,3,3-trifluoropropyltrimethoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, ethyl triacetoxysilane, di-butoxy diacetoxysilane, phenyl-tripropionoxysilane, methyltris(methylethylketoximo)silane, vinyl-tris-methylethylketoximo) silane, methyltris(methylethylketoximino) silane, methyltris(isopropenoxy)silane, vinyltris(isopropenoxy) silane, ethylpolysilicate, n-propylorthosilicate, ethylorthosilicate and dimethyltetraacetoxydisiloxane, alkylalkenylbis(N-alkylacetamido) silanes, dialkylbis(N-arylacetamido) silanes, alkylalkenylbis(N-arylacetamido) silanes, or dimethyldi-(N-phenylacetamido)silane;

ii) the catalyst in cure package (d) is a condensation catalyst selected from organic tin IV metal catalysts, tin II catalysts, 2-ethylhexoates of iron, cobalt, manganese, lead and zinc, titanates, chelated titanates, zirconates and chelated zirconates; or

iii) both i) and ii).

4. The phenylorganosiloxane polymer composition in accordance with claim 1 , wherein the cross-linker in cure package (d) is selected from one or more of a disilaalkane, alkyltrialkoxysilane, alkenyltrialkoxy silane, phenyltrimethoxysilane, alkoxytrioximosilane, alkenyltrioximosilane, 3,3,3-trifluoropropyltrimethoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, ethyl triacetoxysilane, di-butoxy diacetoxysilane, phenyl-tripropionoxysilane, methyltris(methylethylketoximo) silane, vinyl-tris-methylethylketoximo) silane, methyltris(methylethylketoximino)silane, methyltris(isopropenoxy) silane, vinyltris(isopropenoxy)silane, ethylpolysilicate, n-propylorthosilicate, ethylorthosilicate and dimethyltetraacetoxydisiloxane, alkylalkenylbis(N-alkylacetamido) silanes, dialkylbis(N-arylacetamido) silanes, alkylalkenylbis(N-arylacetamido) silanes, or dimethyldi-(N-phenylacetamido) silane.

5. The phenylorganosiloxane polymer composition in accordance with claim 4 , wherein the catalyst in cure package (d) is a condensation catalyst selected from organic tin IV metal catalysts, tin II catalysts, 2-ethylhexoates of iron, cobalt, manganese, lead and zinc, titanates, chelated titanates, zirconates and chelated zirconates.

6. The phenylorganosiloxane polymer composition in accordance with claim 1 , further comprising one or more extenders, plasticizers, adhesion promoters, light stabilizers and/or fungicides.

7. The phenylorganosiloxane polymer composition in accordance with claim 6 , wherein:

i) the cross-linker in cure package (d) is selected from one or more of a disilaalkane, alkyltrialkoxysilane, alkenyltrialkoxy silane, phenyltrimethoxysilane, alkoxytrioximosilane, alkenyltrioximosilane, 3,3,3-trifluoropropyltrimethoxysilane, methyltriacetoxysilane, vinyltriacetoxysilane, ethyl triacetoxysilane, di-butoxy diacetoxysilane, phenyl-tripropionoxysilane, methyltris(methylethylketoximo)silane, vinyl-tris-methylethylketoximo) silane, methyltris(methylethylketoximino) silane, methyltris(isopropenoxy)silane, vinyltris(isopropenoxy) silane, ethylpolysilicate, n-propylorthosilicate, ethylorthosilicate and dimethyltetraacetoxydisiloxane, alkylalkenylbis(N-alkylacetamido) silanes, dialkylbis(N-arylacetamido) silanes, alkylalkenylbis(N-arylacetamido) silanes, or dimethyldi-(N-phenylacetamido)silane;

ii) the catalyst in cure package (d) is a condensation catalyst selected from organic tin IV metal catalysts, tin II catalysts, 2-ethylhexoates of iron, cobalt, manganese, lead and zinc, titanates, chelated titanates, zirconates and chelated zirconates; or

iii) both i) and ii).

8. The phenylorganosiloxane polymer composition in accordance with claim 1 , wherein resin (b) is a mixture of two or more phenyl siloxane resins.

9. The phenylorganosiloxane polymer composition in accordance with claim 1 , stored in two or more parts prior to use and comprising i) a first part containing polymer (a) and filler (c) and ii) a second part containing cross-linker and catalyst and optionally, an adhesion promoter.

10. The phenylorganosiloxane polymer composition in accordance with claim 9 , wherein resin (b) is contained in both the first part i) and the second part ii).

11. The phenylorganosiloxane polymer composition in accordance with claim 9 , wherein resin (b) is present in the first part i) and another resin (b) is present in the second part ii).

12. A sealant derived from the phenylorganosiloxane polymer composition in accordance with claim 1 .

13. A method of sealing a space between two units, said method comprising applying the phenylorganosiloxane polymer composition in accordance with claim 1 in the space between the two units and causing or allowing the phenylorganosiloxane polymer composition to cure.

14. A glazing structure or building unit which includes a sealant derived from the phenylorganosiloxane polymer composition in accordance with claim 1 .