Addition-curable silicon adhesive compositions and bis(trialkoxysilyl)alpha-amino ester adhesion promoters

An addition-curable composition consisting essentially of, by weight:

• (A) 100 parts of a vinyl-containing polydiorganosiloxane composition comprising:
• (1) about 50-100 parts of an essentially cyclic-free vinyl-terminated polydiorganosiloxane having the general formula,
• R.sub.2 ViSiO(R.sub.2 SiO).sub.m (RViSiO).sub.n SiR.sub.2 Vi,
• where Vi is a vinyl radical;
• R is selected from the class consisting of alkyl radicals having 1 to 8 carbon atoms, phenyl radicals, fluoroalkyl radicals having 3 to 10 carbon atoms and mixtures thereof and the value of m+n is sufficient to provide a viscosity of 100-100,000 centipoise at 25.degree. C. and a vinyl content of about 0.02-2.0& by weight;
• and
• (2) about 0-50 parts of a solid, benzene-soluble vinyl-containing resin copolymer comprising (R.sup.1).sub.3 SiO.sub.1/2 units and SiO.sub.4/2 units, where R.sup.1 is a vinyl radical or a monovalent hydrocarbon radical free of aliphatic unsaturation and containing no more than six carbon atoms, the ratio of (R.sup.1).sub.3 SiO.sub.1/2 units to SiO.sub.4/2 units being about 0.5-1.5:1;
• said copolymer having a vinyl content of about 1.5-3.5% by weight;
• (B) about 1-20 parts of a hydrogen-containing polysiloxane having an average unit formula,
• (R.sup.2).sub.a H.sub.b SiO.sub.(4-a-b)/2,
• where R.sup.2 is a monovalent hydrocarbon radical or halogenated monovalent hydrocarbon radical having about 1-10 carbon atoms and free of aliphatic unsaturation, a has a value of about 0-3, b has a value of about 0-3 and a+b has a value of 0-3;
• (C) a catalytic amount of a hydrosilylation catalyst,
• (D) 0.6-2.0 parts, per 100 parts of said addition-curable composition, of a bis(trialkyloxysilyl)alpha-amino ester having the formula
• (R.sup.3 O).sub.3 SiR.sup.4 OC(O)CH.sub.2 N(H)R.sup.5 Si(OR.sup.3).sub.3,
• where R.sup.3 is selected from the same or different C.sub.1-4 alkyl radicals and R.sup.4 and R.sup.5 are selected from the same or different C.sub.2-8 alkylene radicals;
• (E) about 0-200 parts of an extending filler and
• (F) about 0-50 parts of a reinforcing filler, and in the absence of (A)(2), an amount thereof effective for reinforcement.