Curable hotmelt silicone composition, encapsulant, film and optical semiconductor device
A curable hot-melt silicone composition exhibits excellent mechanical properties, particularly strength and extension, even when formed in a film or sheet shape. The curable hot-melt silicone composition contains (A) alkenyl group-containing organopolysiloxane having at least 2 alkenyl groups per molecule, (B) branched organohydrogenpolysiloxane having at least 2 silicon-bonded hydrogen atoms per molecule, at 0.1 to 5% by mass relative to the total mass of the composition, (C) additive represented by average unit formula (C-1), (D) hydrosilylation catalyst, and (E) silica.
1. A solvent-free curable hot-melt silicone composition containing:
(A) alkenyl group-containing organopolysiloxane having at least 2 alkenyl groups per molecule, wherein the alkenyl group-containing organopolysiloxane comprises a resinous organopolysiloxane containing alkenyl group and at least one (Ar 2 SiO 2/2 ) unit,
(B) resinous organohydrogenpolysiloxane having at least 2 silicon-bonded hydrogen atoms per molecule, at 0.1 to 5% by mass relative to the total mass of the composition,
(C) additive represented by average unit formula (C-1): (R 1 3 SiO 1/2 ) a (R 1 2 SiO 2/2 ) b (R 1 SiO 3/2 ) c (in the formula, R 1 is an identical or different alkyl group, aryl group, alkenyl group, aralkyl group, or epoxy group-containing organic group or alkoxy group, wherein at least one of R 1 is an alkenyl group, and at least one of R 1 is an epoxy group-containing organic group; and a, b, and c are numbers that satisfy 0≤a≤1.0, 0≤b≤1.0, 0≤c≤0.9, respectively, and a+b+c=1),
(D) hydrosilylation catalyst, and
(E) silica.
2. The curable hot-melt silicone composition as claimed in claim 1 , where component (A) further contains linear alkenyl group-containing organopolysiloxane.
3. The curable hot-melt silicone composition as claimed in claim 2 , where component (B) is represented by average unit formula (B-1): (R 3 3 SiO 1/2 ) a (R 3 2 SiO 2/2 ) b (R 3 SiO 3/2 ) c (SiO 4/2 ) d (XO 1/2 ) e (in the formula, R 3 is an identical or different hydrogen atom or halogen-substituted or unsubstituted monovalent hydrocarbon group, where at least two R 3 are hydrogen atoms; X is a hydrogen atom or alkyl group; and a, b, c, d, and e are numbers that satisfy 0≤a≤1.0, 0≤b≤1.0, 0≤c≤0.9, 0≤d≤0.5, 0≤e≤0.4, a+b+c+d=1.0, and c+d>0).
4. The curable hot-melt silicone composition as claimed in claim 3 , where, in said average unit formula (B-1), a is in the range 0.1≤a≤0.9, b is in the range 0≤b≤0.8, c is in the range 0.1≤c≤0.9, d is in the range 0≤d≤0.4, and e is in the range 0≤e≤0.3.
5. The curable hot-melt silicone composition as claimed in claim 2 , where, in said average unit formula (C-1), a is in the range 0≤a≤0.9, b is in the range 0.1≤b≤0.9, and c is in the range 0.01≤c≤0.8.
6. The curable hot-melt silicone composition as claimed in claim 2 , where the alkenyl group content in component (C) is ≥5 mol % the total amount of R 1 .
7. The curable hot-melt silicone composition as claimed in claim 1 , where component (B) is represented by average unit formula (B-1): (R 3 3 SiO 1/2 ) a (R 3 2 SiO 2/2 ) b (R 3 SiO 3/2 ) c (SiO 4/2 ) d (XO 1/2 ) e (in the formula, R 3 is an identical or different hydrogen atom or halogen-substituted or unsubstituted monovalent hydrocarbon group, where at least two R 3 are hydrogen atoms; X is a hydrogen atom or alkyl group; and a, b, c, d, and e are numbers that satisfy 0≤a≤1.0, 0≤b≤1.0, 0≤c≤0.9, 0≤d≤0.5, 0≤e≤0.4, a+b+c+d=1.0, and c+d>0).
8. The curable hot-melt silicone composition as claimed in claim 7 , where, in said average unit formula (B-1), a is in the range 0.1≤a≤0.9, b is in the range 0≤b≤0.8, c is in the range 0.1≤c≤0.9, d is in the range 0≤d≤0.4, and e is in the range 0≤e≤0.3.
9. The curable hot-melt silicone composition as claimed in claim 7 , where, in said average unit formula (C-1), a is in the range 0≤a≤0.9, b is in the range 0.1≤b≤0.9, and c is in the range 0.01≤c≤0.8.
10. The curable hot-melt silicone composition as claimed in claim 7 , where the alkenyl group content in component (C) is ≥5 mol % the total amount of R 1 .
11. The curable hot-melt silicone composition as claimed in claim 1 , where, in said average unit formula (C-1), a is in the range 0≤a≤0.9, b is in the range 0.1≤b≤0.9, and c is in the range 0.01≤c≤0.8.
12. The curable hot-melt silicone composition as claimed in claim 11 , where the alkenyl group content in component (C) is ≥5 mol % the total amount of R 1 , and where the epoxy group-containing organic group content in component (C) is ≥5 mol % the total amount of R 1 .
13. The curable hot-melt silicone composition as claimed in claim 1 , where the alkenyl group content in component (C) is ≥5 mol % the total amount of R 1 .
14. The curable hot-melt silicone composition as claimed in claim 1 , where the epoxy group-containing organic group content in component (C) is ≥5 mol % the total amount of R 1 .
15. The curable silicone composition as claimed in claim 1 , which further contains linear and cyclic organopolysiloxane as component (A).
16. A film obtained by solidifying the curable hot-melt silicone composition as claimed in claim 1 .
17. An encapsulant comprising the curable hot-melt silicone composition as claimed in claim 1 .
18. An optical semiconductor element containing the encapsulant as claimed in claim 17 .
19. The optical semiconductor element as claimed in claim 18 , where the optical semiconductor is a light-emitting diode.
20. The curable hot-melt silicone composition as claimed in claim 1 , further comprising (B′) linear organohydrogenpolysiloxane having at least 2 silicon-bonded hydrogen atoms per molecule.