Curable silicone resin composition, cured product thereof, and opaque silicone adhesive sheet formed from the composition

A silicone resin cured product obtained by curing a curable silicone resin composition that is solid at room temperature and that comprises:

• (A) an organopolysiloxane having a resin structure, consisting of R1SiO1.5 units, R22SiO units and R3aR4bSiO(4-a-b)/2 units, wherein, R1, R2 and R3 each independently represents a hydroxyl group, methyl group, ethyl group, propyl group, cyclohexyl group or phenyl group, each R4 independently represents a vinyl group or allyl group, a represents 0, 1 or 2, and b represents 1 or 2, provided that a+b is 2 or 3, and
• including a structure in which at least a portion of the R22SiO units are connected in a continuous repeating sequence, and a number of units in the repeating sequence is within a range from 5 to 50,
• (B) an organohydrogenpolysiloxane having a resin structure, consisting of R1SiO1.5 units, R22SiO units and R3cHdSiO(4-c-d)/2 units, wherein, R1, R2 and R3 are each independently as defined above, c represents 0, 1 or 2, and d represents 1 or 2, provided that c+d is 2 or 3, and
• including a structure in which at least a portion of the R22SiO units are connected in a continuous repeating sequence, and a number of units in the repeating sequence is within a range from 5 to 50:
• in sufficient amount that a molar ratio of hydrogen atoms bonded to silicon atoms within component (B) relative to a combined total of vinyl groups and allyl groups within component (A) is within a range from 0.1 to 4.0,
• (C) a platinum group metal-based catalyst:
• in an effective amount,
• (D) either one or both of an opaque pigment and an opaque dye, and
• (E) a reaction retarder, wherein
• a layer of thickness 100 μm formed from a cured product of the composition exhibits a light transmittance of not more than 5% across an entire visible light range.

A cured product obtained by curing a curable silicone resin composition, the cured product having a light transmittance of not more than 5% across an entire visible light range when formed as a layer with a thickness of 100 μm, wherein

• the composition comprises:
• (A) an organopolysiloxane having a resin structure, consisting of R1SiO1.5 units, R22SiO units and R3aR4bSiO(4-a-b)/2 units, wherein, R1, R2 and R3 each independently represents a hydroxyl group, methyl group, ethyl group, propyl group, cyclohexyl group or phenyl group, each R4 independently represents a vinyl group or allyl group, a represents 0, 1 or 2, and b represents 1 or 2, provided that a+b is 2 or 3, and
• including a structure in which at least a portion of the R22SiO units are connected in a continuous repeating sequence, and a number of units in the repeating sequence is within a range from 5 to 50,
• (B) an organohydrogenpolysiloxane having a resin structure, consisting of R1SiO1.5 units, R22SiO units and R3cHdSiO(4-c-d)/2 units, wherein, R1, R2 and R3 are each independently as defined above, c represents 0, 1 or 2, and d represents 1 or 2, provided that c+d is 2 or 3, and
• including a structure in which at least a portion of the R22SiO units are connected in a continuous repeating sequence, and a number of units in the repeating sequence is within a range from 5 to 50:
• in sufficient amount that a molar ratio of hydrogen atoms bonded to silicon atoms within component (B) relative to a combined total of vinyl groups and allyl groups within component (A) is within a range from 0.1 to 4.0,
• (C) a platinum group metal-based catalyst:
• in an effective amount,
• (D) either one or both of an opaque pigment and an opaque dye, and
• (E) a reaction retarder.

An opaque silicone adhesive sheet formed from a curable silicone resin composition that is solid at room temperature and that comprises:

• (A) an organopolysiloxane having a resin structure, consisting of R1SiO1.5 units, R22SiO units and R3aR4bSiO(4-a-b)/2 units, wherein, R1, R2 and R3 each independently represents a hydroxyl group, methyl group, ethyl group, propyl group, cyclohexyl group or phenyl group, each R4 independently represents a vinyl group or allyl group, a represents 0, 1 or 2, and b represents 1 or 2, provided that a+b is 2 or 3, and
• including a structure in which at least a portion of the R22SiO units are connected in a continuous repeating sequence, and a number of units in the repeating sequence is within a range from 5 to 50,
• (B) an organohydrogenpolysiloxane having a resin structure, consisting of R1SiO1.5 units, R22SiO units and R3cHdSiO(4-c-d)/2 units, wherein, R1, R2 and R3 are each independently as defined above, c represents 0, 1 or 2, and d represents 1 or 2, provided that c+d is 2 or 3, and
• including a structure in which at least a portion of the R22SiO units are connected in a continuous repeating sequence, and a number of units in the repeating sequence is within a range from 5 to 50:
• in sufficient amount that a molar ratio of hydrogen atoms bonded to silicon atoms within component (B) relative to a combined total of vinyl groups and allyl groups within component (A) is within a range from 0.1 to 4.0,
• (C) a platinum group metal-based catalyst:
• in an effective amount,
• (D) either one or both of an opaque pigment and an opaque dye, and
• (E) a reaction retarder, wherein
• a layer of thickness 100 μm formed from a cured product of the composition exhibits a light transmittance of not more than 5% across an entire visible light range.

A method of protecting an electronic component and shielding the electronic component from light, the method comprising adhering or pressure bonding a curable silicone resin composition to a surface of the electronic component, and then curing the composition, wherein

• the composition is solid at room temperature and comprises:
• (A) an organopolysiloxane having a resin structure, consisting of R1SiO1.5 units, R22SiO units and R3aR4bSiO(4-a-b)/2 units, wherein, R1, R2 and R3 each independently represents a hydroxyl group, methyl group, ethyl group, propyl group, cyclohexyl group or phenyl group, each R4 independently represents a vinyl group or allyl group, a represents 0, 1 or 2, and b represents 1 or 2, provided that a+b is 2 or 3, and
• including a structure in which at least a portion of the R22SiO units are connected in a continuous repeating sequence, and a number of units in the repeating sequence is within a range from 5 to 50,
• (B) an organohydrogenpolysiloxane having a resin structure, consisting of R1SiO1.5 units, R22SiO units and R3cHdSiO(4-c-d)/2 units, wherein, R1, R2 and R3 are each independently as defined above, c represents 0, 1 or 2, and d represents 1 or 2, provided that c+d is 2 or 3, and
• including a structure in which at least a portion of the R22SiO units are connected in a continuous repeating sequence, and a number of units in the repeating sequence is within a range from 5 to 50:
• in sufficient amount that a molar ratio of hydrogen atoms bonded to silicon atoms within component (B) relative to a combined total of vinyl groups and allyl groups within component (A) is within a range from 0.1 to 4.0,
• (C) a platinum group metal-based catalyst:
• in an effective amount,
• (D) either one or both of an opaque pigment and an opaque dye, and
• (E) a reaction retarder, wherein
• a layer of thickness 100 μm formed from a cured product of the composition exhibits a light transmittance of not more than 5% across an entire visible light range.