Solventless addition-curable pressure sensitive silicone adhesive composition and adhesive article

摘要

A solventless addition-curable pressure sensitive silicone adhesive composition is provided. The composition comprises (A) an alkenyl group-containing polydiorganosiloxane; (B) a condensation product of (a) a polydiorganosiloxane having hydroxyl group or an alkoxy group on opposite ends of the molecular chain and (b) a polyorganosiloxane containing R13SiO1/2 unit and SiO2 unit as critical components and also a HOSiO3/2 unit in the molecule; (C1) a polyorganohydrosiloxane having at least three SiH groups per molecule; (C2) a polydiorganohydrosiloxane having SiH group on opposite ends; and (D) a platinum group metal catalyst. Use of the present composition enables production of a pressure sensitive adhesive agent having flexibility, pressure sensitive adhesiveness, and heat resistance, and the present composition is particularly effective for use as a buffer member having pressure sensitive adhesiveness.

主权项

1. A solventless addition-curable pressure sensitive silicone adhesive composition, consisting of:
(A) a polydiorganosiloxane having at least two alkenyl group-containing organic groups per molecule represented by formula (1):
XbR3-bSiO—[R2SiO]a—SiXbR3-b  (1)  wherein X is an alkenyl group-containing organic group containing 2 to 10 carbon atoms, R is independently a monovalent hydrocarbon group containing 1 to 10 carbon atoms, a is an integer of 50≦a ≦2,000, and b is an integer of 1 to 3, (B) a condensation product of the SiOR2 group of the following component (a) with the SiOH group of the following component (b):
(a) a polydiorganosiloxane having hydroxyl group or an alkoxy group on opposite ends of the molecular chain represented by formula (2):
(R2O)R12SiO—[R12SiO]c—SiR12(OR2)  (2)  wherein R1 is independently a monovalent hydrocarbon group containing 1 to 10 carbon atoms excluding alkenyl group-containing organic groups, R2 is hydrogen atom or R1, and c is an integer of 50≦c≦2,000, and
(b) a polyorganosiloxane containing R13SiO1/2 unit (wherein R1 is as defined above), SiO2 unit, and a siloxane unit having hydroxyl group bonded to the silicon atom wherein molar ratio of the R13SiO1/2 unit to the SiO2 unit is 0.6 to 1.0 and content of the hydroxyl group is at least 0.1% by weight and less than 1.8% by weight, with the proviso that the component (A) is 10 to 90 parts by weight, the component (a) is 5 to 60 parts by weight, and the component (b) is 5 to 60 parts by weight in relation to 100 parts by weight of the total of the components (A), (a), and (b), (C) component (C1) of a polyorganohydrosiloxane having at least three SiH groups per molecule, or the component (C1) and component (C2) of a polydiorganohydrosiloxane having SiH group on opposite ends represented by formula (3):
HR12SiO—[R12SiO]d—SiR12H  (3)  wherein R1 is as defined above and d is an integer of 5≦d≦500  (with the proviso that molar ratio of the SiH group in the component (C1) to the alkenyl group in the component (A) is 0.2 to 15, and molar ratio of the SiH group in the component (C2) to the alkenyl group in the component (A) is 0 to 5), (D) a platinum group metal catalyst (1 to 500 ppm by weight in terms of the platinum group metal in relation to the total of the components (A), (a), and (b)), and (E) a reaction regulator agent at 0.005 to 5 parts by weight in relation to 100 parts by weight of the total of components (A), (a), and (b).