Curing-reactive organopolysiloxane resin, pressure-sensitive adhesive composition using same, and use thereof
A curing-reactive organopolysiloxane composition is provided. The composition generally forms a pressure-sensitive adhesive layer which is curable by a hydrosilylation reaction, has excellent adhesiveness and handleability, and is capable of maintaining high transparency over an extended period of time without developing problems such as discoloration or coloration, even when subjected to long-term aging at a high temperature and even when exposed to high-energy rays such as UV rays over an extended period of time. The curing-reactive organopolysiloxane composition can be cured via hydrosilylation reaction. A content of platinum-based metal among a solid content is in the range of from 0.1 to 50 ppm. An adhesive force of a cured layer with a thickness of 50 μm obtained by curing the composition is not less than 0.02N/25 mm. A pressure-sensitive adhesive layer obtained by curing the composition, and an electronic part or a display device using the same, are also provided.
1 . An electronic part or a display device containing an electronic material or member for a display device, the electronic material or member being obtained by curing a curing-reactive organopolysiloxane composition which comprises 0.1 to 50 ppm platinum-based metal based on the total amount of the solid content of the curing-reactive organopolysiloxane composition, wherein an adhesive force of a polymethyl methacrylate sheet, with a thickness of 2 mm provided with a cured layer with a thickness of 50 μm obtained by curing the curing-reactive organopolysiloxane composition, as measured at a tensile speed of 300 mm/min using a 180° peel test method according to JIS Z 0237, is not lower than 0.02 N/25 mm;
wherein the curing-reactive organopolysiloxane composition comprises the following components (A) to (C):
(A) a straight-chain or branched-chain organopolysiloxane having a number of alkenyl groups greater than 1 on average in the molecule;
(B) an organopolysiloxane resin, where at least a part of the component (B) is a resin which consists of R 3 SiO 1/2 units and SiO 4/2 units and optionally having a hydroxyl group or a hydrolyzable group, wherein R is a monovalent organic group and not less than 90 mol % of R is an alkyl group or a phenyl group; and
(C) an organohydrogenpolysiloxane having at least two Si—H bonds in the molecule;
wherein a molar ratio of silicon-bonded hydrogen atom (SiH) groups in the component (C) to alkenyl groups in the curing-reactive organopolysiloxane composition is in a range of from 0.1 to 100;
wherein at least a part of the component (A) is (A1) an alkenyl group-containing organopolysiloxane having a viscosity of not less than 100,000 mPa-s at 25° C. or having a plasticity in a range of from 50 to 200 as measured in accordance with a method as prescribed in JIS K6249;
wherein a content of a vinyl (CH 2 ═CH) portion in the alkenyl group in the component (A1) is in a range of from 0.005 to 0.400 wt. %, and
wherein a content of the component (B) is in a range of from 1 to 500 parts by mass with respect to a total of 100 parts by mass of the components (A) and (C) in the curing-reactive organopolysiloxane composition.
2 . The electronic part or display device of claim 1 , wherein a b* value, which is measured with an L*a*b* color system as prescribed in JIS Z 8729, of the electronic material or member with a thickness of 100 μm, is not greater than 0.15.
3 . The electronic part or display device of claim 1 , wherein when the electronic material or member having a thickness of 100 μm is aged for 300 hours at 105° C. or irradiated for 75 hours with UV light using a mercury lamp with an intensity of 12 mW/cm 2 at 365 nm and an intensity of 3.5 mW/cm 2 at 254 nm, a change (Δb*) in a b* value of the electronic material or member measured before and after thermal aging or before and after UV irradiation measured with an L*a*b* color system as prescribed in JIS Z 8729 is not greater than 0.20.
4 . The electronic part or display device of claim 1 , wherein the curing-reactive organopolysiloxane composition comprises 0.1 to 30 ppm platinum-based metal based on the total amount of the solid content of the curing-reactive organopolysiloxane composition; the electronic material or member having a thickness of 100 μm obtained by curing the curing-reactive organopolysiloxane composition is substantially transparent; a b*value thereof measured with an L*a*b* color system as prescribed in JIS Z 8729 is not greater than 0.10; and when the electronic material or member is aged for 300 hours at 105° C. or irradiated for 75 hours with UV light using a mercury lamp with an intensity of 12 mW/cm 2 at 365 nm and an intensity of 3.5 mW/cm 2 at 254 nm, a change (Δb*) in a b* value of the electronic material or member before and after thermal aging or before and after UV irradiation with an L*a*b* color system as prescribed in JIS Z 8729 is not greater than 0.15.
5 . The electronic part or display device of claim 1 , wherein the curing-reactive organopolysiloxane composition further comprises at least one type of (D) curing retarder.
6 . The electronic part or display device of claim 1 , wherein a viscosity of the curing-reactive organopolysiloxane composition after 8 hours at room temperature from immediately after preparation of the curing-reactive organopolysiloxane composition is not greater than 1.5 times that of a viscosity immediately after the preparation of the curing-reactive organopolysiloxane composition, and the curing-reactive organopolysiloxane composition is curable at 80 to 200° C.