Moldable silicone elastomers having selective primerless adhesion
AssigneeBryant Rubber Corporation
InventorRick A. Ziebell
Life of this patent
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Abstract
Organopolysiloxane compositions that cure by the addition reaction of silicon-bonded lower alkenyl radicals with silicon-bonded hydrogen atoms and which exhibit select adhesion to a variety of substrates. The compositions comprise an adhesion promoting mixture comprising an epoxy-functional compound, soluble polydiorganosiloxanes, polycycloorganosiloxanes (linear and cyclic) and and hydroxy end blocked hydrocarbons (glycols) thus giving release characteristics to metal substrates while maintaining adhesion to a thermoplastic substrate. Additionally, an additive may be used to produce surface lubricity after curing.
Claims4
A curable organopolysiloxane composition having selective adhesion to a substrate, said composition containing the following components:
- (A) an organopolysiloxane polymer;
- wherein there is up to 100 parts by weight of the organopolysiloxane polymer having a viscosity of about 10,000 to about 10,000,000 centipoises at 25° C. with sufficient vinyl, or mixtures of such organopolysiloxane to provide functional reactivity with a crosslinker organohydrogenpolysiloxane;
- (B) an organohydrogenpolysiloxane crosslinker;
- wherein there is from 0.3 to 40 parts by weight of the organohydrogenpolysiloxane crosslinker containing at least two silicon-bonded hydrogens per molecule;
- (C) a platinum group metal catalyst;
- wherein there is a catalytically effective amount of the platinum group metal catalyst;
- (D) a cure inhibitor;
- wherein there is from 0.01 to 3 parts by weight of the cure inhibitor of the type ethynyl cyclohexanol;
- (E) an adhesion promoter;
- wherein there is from 0.01 to 30 parts by weight of a compound comprising at least one hydroxy group and in the same molecule at least one substituent selected from a group consisting of silicon hydride, alkenyl, and acryl;
- (F) an epoxy functional compound;
- wherein there is from 0.01 to 30 parts by weight of the epoxy functional compound;
- and
- (G) a compound selected from the group consisting of soluble polydiorganosiloxanes, polycycloorganosiloxanes, glycols, and mixtures thereof;
- wherein there is up to about 10 parts by weight based upon the total composition of a mold release agent compound that is selected from the group consisting of soluble fluid polydiorganosiloxanes, polycycloorganosiloxanes (linear and cyclic), hydroxy end blocked hydrocarbons and having a molecular distribution such that the viscosity is 50 to 10,000 centipoises at 25° C.
A composite comprising an epoxy-coated substrate having bonded thereto a cured organopolysiloxane, said cured organopolysiloxane composition having selective adhesion to the epoxy-coated substrate, said composition containing the following components:
- (A) an organopolysiloxane polymer;
- (B) an organohydrogenpolysiloxane crosslinker;
- (C) a platinum group metal catalyst;
- (D) a cure inhibitor;
- (E) an adhesion promoter;
- (F) an epoxy functional compound;
- and
- (G) a compound selected from the group consisting of soluble polydiorganosiloxanes, polycycloorganosiloxanes, glycols, and mixtures thereof.
Dependencies are inferred from the claim text.