Abstract: A platinum group-metal curing liquid silicone rubber compositions having improved physical properties such as tear and heat-aging, especially at durometers below about 35 and above about 65. The present inventors have unexpectedly discovered that the addition of diorganohydrogensiloxy end-blocked polydiorganosiloxanes and triorganosiloxy end-blocked polydiorganosiloxanes having a viscosity greater than about 10 Pa.cndot.s at 25.degree. C. to liquid silicone rubber compositions can provide for the described improved properties.

Abstract: The instant invention pertains to a method of producing silicone pressure sensitive adhesives wherein the method comprises (I) combining together (A) a benzene soluble, hydroxyl containing organopolysiloxane resin consisting essentially of R.sub.3 SiO.sub.1/2 siloxane units and SiO.sub.4/2 siloxane units, wherein R is a monovalent radical selected from the group consisting of hydrocarbon and halogenated hydrocarbon radicals having from 1 to 10 carbon atoms; there being from 0.5 to 1.5 R.sub.3 SiO.sub.1/2 units for every SiO.sub.4/2 units and there being 1.0 to 4 wt %, based on FTIR, hydroxyl functionality and (B) a hydroxyl containing polydiorganosiloxane having a viscosity of .gtoreq.100 mPa's and (C) a catalyst selected from the group consisting of a weak organic acid or metal salt thereof; and thereafter (II) heating the mixture of (A), (B) and (C) for a time sufficient to produce the silicone pressure sensitive adhesive.

Abstract: Siloxanyl-phosphate mixtures are prepared by reacting cyclopolydimethylsiloxane and a silylphosphate mixture. The siloxanyl-phosphate mixture is a mixture of 5 to 30 weight percent of a monosiloxanyl-phosphate of the formula ##STR1## 70 to 85 weight percent of a disiloxanyl-phosphate of the formula ##STR2## 2 to 11 weight percent of a trisiloxanyl-phosphate of the formula wherein x has an average value of from 3 to 30.These siloxanyl-phosphate mixtures are useful in stabilizing basic polymerization catalyst such as potassium hydroxide or potassium silanolate and can either be used effectively per se or in combination with carbon dioxide.

Abstract: Silylphosphate mixtures are prepared by slowly adding phosphoric acid to hexamethyldisiloxane under reflux while removing the by-produced water and after the phosphoric acid is added, the temperture is increased to from 150.degree. C. to 170.degree. C. to recover the silylphosphate mixture residue. The mixture has from 10 to 30 weight percent of a monosilyl phosphate of the formula{(CH.sub.3).sub.3 SiO}(HO).sub.2 P.dbd.O,65 to 85 weight percent of a disilyl phosphate of the formula{(CH.sub.3).sub.3 SiO}.sub.2 (HO)P.dbd.O,and 2 to 7 weight percent of a trisilyl phosphate of the formula{(CH.sub.3).sub.3 SiO}.sub.3 P.dbd.O.These silylphosphate mixtures are useful in stabilizing basic polymerization catalyst such as potassium hydroxide or potassium silanolate and can either be used effectively per se or in combination with carbon dioxide.

Abstract: Silicone rubber compositions prepared from polydiorganosiloxane and small amounts of alkali metal hydrogen phosphates or alkali metal hydrogen phosphites improve the properties of the silicone rubber, such as compression set and flame retardancy.

Abstract: A method of reducing the reaction between polydiorganosiloxane gum and reinforcing silica, which causes "creping", has been discovered. The method mixes crude polydiorganocyclosiloxane with a carbonate or bicarbonate salt of potassium or cesium, heats the mixture, then filters to remove the salt. The treated material can be further purified by stripping this filtered material to give a polydiorganocyclosiloxane having a hydroxyl content of less than 1 part per million of polydiorganocyclosiloxane.

Abstract: A method of producing an improved extruding silicone rubber stock consists essentially of mixing together a polydiorganosiloxane having a Williams Plasticity Number of from 125 to 180 and a get slope activity of less than 25 and a reinforcing silica filler having a surface area of greater than 150 m.sup.2 /g and a hydrophobic surface from a silane treatment to give a stock which has a Garvey rating of greater than 3.5 at an extrusion rate of 20 rpm.