Method of preparing a curable polyorganosiloxane composition

Patent metadata

Field	Value
Publication number	US-9303164-B2
Application number	US-201414524036-A
Country	US
Kind code	B2
Filing date	Oct 27, 2014
Priority date	Oct 14, 2010
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A method of preparing a curable polyorganosiloxane composition including kneading a uniform mixture of an alkenyl group-containing polyorganosiloxane, a polyorganohydrogensiloxane, and a platinum group metal compound, and defoaming the kneaded mixture under reduced pressure, the alkenyl group-containing polyorganosiloxane includes a linear polyorganosiloxane of the formula (I):

R is R 1 or R 2 , and at least two Rs are R 1 ; R 1 is C 2 -C 6 alkenyl; R 2 is C 1 -C 6 alkyl; and n is a value that yields a viscosity at 23° C. of 10 to 10,000 cPs, a branched polyorganosiloxane containing SiO 4/2 and R′ 3 SiO 1/2 units, optionally a R′ 2 SiO and/or a R′SiO 3/2 , R′ represents a monovalent aliphatic or alicyclic, and at least three R′ groups per molecule are alkenyls, the alkenyl group-containing polyorganosiloxane having a weight ratio of the branched to linear polyorganosiloxane of 1 to 5; and a number of hydrogens bonded to a silicon atom of the polyorganohydrogensiloxane exceeds 2.

First claim

The invention claimed is:

1. A method of preparing a curable polyorganosiloxane composition, the method comprising:
(a) kneading a uniform mixture of an alkenyl group-containing polyorganosiloxane, a polyorganohydrogensiloxane, and a platinum group metal compound, and
(b) defoaming the resultant kneaded mixture from step (a) under reduced pressure, wherein
(A) the alkenyl group-containing polyorganosiloxane comprises
(i) a linear polyorganosiloxane represented by a formula (I) as follows:

wherein each R group is independently a R1 group or a R2 group, and at least two R groups are R1 groups; each R1 group is independently a C2-C6 a\keny\ group; each R2 group is independently a C1-C6 alkyl group; and n is a value that yields a viscosity at 23° C. of 50 to 2,500 cPs, and
(ii) a branched polyorganosiloxane comprising a SiO 4/2 unit and a R′ 3 SiO 1/2 unit, and optionally a R′ 2 SiO unit and/or a R′SiO 3/2 unit, wherein each R′ group independently represents an unsubstituted or substituted, monovalent aliphatic group or alicyclic group, and at least three R′ groups per molecule are alkenyl groups,
the alkenyl group-containing polyorganosiloxane having a weight ratio of the branched polyorganosiloxane to the linear polyorganosiloxane of 2.0 to 3.0, and, when the optional R′SiO 3/2 unit is present in the branched polyorganosiloxane, a weight ratio of the SiO 4/2 unit and the R′SiO 3/2 unit is 25 to 50% by weight based on the total weight of the linear polyorganosiloxane and the branched polyorganosiloxane; and
(B) a number of hydrogen atoms bonded to a silicon atom of the polyorganohydrogensiloxane exceeds 2.

2. The method according to claim 1 , wherein the R 1 group is a vinyl group and the alkenyl R′ groups are vinyl groups.

3. The method according to claim 1 , wherein the polyorganohydrogensiloxane is represented by a formula (II′) as follows:

wherein each R 3a group independently represents an unsubstituted or substituted, monovalent aliphatic group or alicyclic group containing no aliphatic unsaturated carbon-carbon bond; each R 3b group independently represents a hydrogen atom or an unsubstituted or substituted, monovalent aliphatic group or alicyclic group, p has a value from 2 to 100, and q has a value from 0 to 100.

4. The method according to claim 1 , wherein the platinum group metal compound is a platinum-vinylsiloxane complex.

5. The method according to claim 1 , further comprising:
adding an inorganic filler to the uniform mixture.

6. The method according to claim 1 , further comprising:
adding 3,5-dimethyl-1-hexyn-3-ol to the uniform mixture.

7. The method according to claim 2 , wherein the polyorganohydrogensiloxane is represented by a formula (II′) as follows:

wherein each R 3a group independently represents an unsubstituted or substituted, monovalent aliphatic group or alicyclic group containing no aliphatic unsaturated carbon-carbon bond; each R 3b group independently represents a hydrogen atom or an unsubstituted or substituted, monovalent aliphatic group or alicyclic group, p has a value from 2 to 100, and q has a value from 0 to 100.

8. An adhesive comprising the curable polyorganosiloxane composition prepared by the method according to claim 1 and an adhesiveness imparting agent.

9. A semiconductor device which is encapsulated by the curable polyorganosiloxane composition prepared by the method according to claim 1 .

10. A method of producing a cured polyorganosiloxane product from the curable polyorganosiloxane composition according to claim 1 , the method comprising:
coating the polyorganosiloxane composition on a suitable substrate, and
curing the resultant polyorganosiloxane composition coating to form a cured product.

11. The method according to claim 10 , wherein the polyorganosiloxane composition coating is cured by heating the polyorganosiloxane composition coating at a temperature between 50 to 250° C. for 1 minute to 24 hours.

Assignees

• Momentive Performance Mat Jp

Inventors

• Takanashi Masanori

Classifications

• H10W74/476

  Organic materials comprising silicon · CPC title

• H10W74/473

  containing a filler · CPC title

• H10W74/40

  characterised by their materials · CPC title

• C08G77/04 Primary

  Polysiloxanes · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title