Boron nitride catalyzed polysiloxane resin blend and composite products formed therefrom
AssigneeThe Gasket King
InventorWilliam A. Clarke
Life of this patent
Estimating the term…
Abstract
Submicron boron nitride is used as a catalyst for thermally activating polysiloxane resins when uniformly mixed with the resin either using anhydrous acetone for wet mixing or simply hot melt mixing. Boron nitride is also used to coat the fibers using a particulate sizing approach. The coated fibers are used to activate the polymer resin blend. Fabric may be impregnated with the resin to mold high temperature composite laminates from which high temperature, non-metallic gaskets may be cut.
Claims22
A polysiloxane resin blend comprising:
- a solid silicone resin;
- a liquid siloxane resin;
- submicron boron nitride as a catalyst in a resin to catalyst weight ratio of about 20/1 to about 5/1;
- and
- a submicron refractory filler.
A process for making a fiber reinforced silica matrix composite product containing refractory fibers which is substantially free of black glass comprising the steps of:
- (a) applying to refractory fibers a lubricating agent of submicron boron nitride particles and a polysiloxane resin composition by either:
- (A) a two step process of
- (1) coating the refractory fibers directly with boron nitride in the form of a thin polysiloxane resin coating which is at less than about 1% of the fiber weight and which contains about 5 to 10% by weight of submicron size boron nitride particles;
- and
- (2) impregnating the coated fibers with a basic polysiloxane resin composition comprising
- (i) a substantial amount of a solid silicone resin dissolved in at least one lower molecular weight liquid siloxane resin;
- (ii) a refractory additive;
- and
- (iii) a curing agent;
- or
- (B) a single step process of impregnating the refractory fibers with a basic polysiloxane resin composition which further contains a lubricating agent comprising:
- a substantial amount of a solid silicone resin dissolved in at least one lower molecular weight liquid siloxane resin;
- (ii) a refractory additive;
- and
- (iii) a curing agent;
- and
- said basic polysiloxane resin composition further containing
- (iv) a lubricating agent comprising boron nitride particles with a particle size of about 1 micron or less
- so that the fiber is lubricated with the boron nitride particles as the fiber is lubricated with the boron nitride particles as the fiber is loaded with the resin;
- and
- (b) heating the resulting mixture from (A) or (B) under a slow controlled heating schedule so as to minimize the formation of black glass.
Dependencies are inferred from the claim text.