# US 5,705,587 A · Room-temperature-curable silicone elastomer composition

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- Number: US 5,705,587 A
- Document ID: US5705587A
- Status: Granted
- Kind: A
- Application number: 08/791,306
- Filed: 1997-01-30
- Granted: 1998-01-06
- Earliest claimed: 1996-01-31
- Assignees: Dow Corning Toray Silicone Co., Ltd.
- Inventors: Hidekatsu Hatanaka; Seiji Hori
- Web page: https://patentgrep.com/patent/US5705587A

## CPC

- C08L 83/04: Polysiloxanes
- C08G 77/14: containing silicon bound to oxygen-containing groups
- C08G 77/16: to hydroxy groups
- Y10S 528/901: Room temperature curable silicon-containing polymer
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A room-temperature-curable silicone elastomer composition obtained from diorganopolysiloxane that is endblocked by silanol at both molecular chain terminals and diorganopolysiloxane that is endblocked at one molecular chain terminal by silanol and at the other terminal by trialkylsiloxy; an alkoxy functional silane; an organopolysiloxane resin; a curing catalyst; and a diorganopolysiloxane that contains at least 2 carboxyl groups. The room-temperature-curable silicone elastomer composition has an excellent pre-cure workability and cures into a low-modulus, high-elongation silicone elastomer.

## Claims

### Claim 1

A room-temperature-curable silicone elastomer composition comprising
(A) 100 weight parts of diorganopolysiloxane composed of
(a) diorganopolysiloxane with a viscosity at 25.degree. C. of 0.02 to 1,000 Pa.s that is endblocked by silanol at both molecular chain terminals and
(b) diorganopolysiloxane with a viscosity at 25.degree. C. of 0.1 to 1,000 Pa.s that is endblocked at one molecular chain terminal by silanol and at the other terminal by trialkylsiloxy in a molar ratio in the range from 1.0:0.3 to 1.0:3.0 moles of (a) to moles of (b);
(B) 0.1 to 20 weight parts of organosilane with the general formula
R.sup.1.sub.(4-a) Si(OR.sup.2).sub.a
R.sup.1 and R.sup.2 each represent C.sub.1 to C.sub.20 monovalent hydrocarbon groups and a is 3 or 4 or partial hydrolyzate thereof;
(C) 5 to 30 weight parts of organopolysiloxane resin that is solid at ambient temperature and that is composed of the R.sup.3.sub.3 SiO.sub.1/2 and SiO.sub.4/2 units in a molar ratio in the range from 0.5:1.0 to 1.2:1.0 and where R.sup.3 is a C.sub.1 to C.sub.20 monovalent hydrocarbon group or the hydroxyl group
(D) 0.01 to 20 weight parts of curing catalyst; and
(E) 0.5 to 10 weight parts diorganopolysiloxane having at least 2 --R.sup.4 --COOR.sup.5 groups in each molecule and having the following average general formula ##STR4## wherein R.sup.4 is a divalent hydrocarbon group, R.sup.5 is the hydrogen atom or a monovalent hydrocarbon group, R.sup.6 is a C.sub.1 to C.sub.20 monovalent hydrocarbon group, A is R.sup.6 or --R.sup.4 --COOR.sup.5, k is a positive integer, 1 is 0 or an integer with a value of at least 1, k+1 is at least 10, and k/(1+2)=5/1 to 500/1.

### Claim 2 (depends on 1)

The room-temperature-curable silicone elastomer composition according to claim 1, in which the moles of component (a): moles of component (b) have a molar ratio in the range from 1.0:0.5 to 1.0:3.0.

### Claim 3 (depends on 1)

The room-temperature-curable silicone elastomer composition according to claim 1, in which in component (B), R.sub.1 is C.sub.8 to C.sub.20 alkyl, R.sup.2 is C.sub.1 or C.sub.2 alkyl, and a is 3.

### Claim 4 (depends on 1)

The room-temperature-curable silicone elastomer composition according to claim 1, in which R.sup.3 in component (C) is methyl.

### Claim 5 (depends on 1)

The room-temperature-curable silicone elastomer composition according to claim 1, in which component (C) has a hydroxyl content no greater than 1 weight %.

### Claim 6 (depends on 1)

The room-temperature-curable silicone elastomer composition according to claim 1, in which the curing catalyst (D) is an organotin compound.

### Claim 7 (depends on 1)

The room-temperature-curable silicone elastomer composition according to claim 1, is a silicone building sealant composition.

### Claim 8

A method of making a room-temperature-curable silicone elastomer composition comprising mixing the following ingredients in the order listed
(A) 100 weight parts of diorganopolysiloxane composed of
(a) diorganopolysiloxane with a viscosity at 25.degree. C. of 0.02 to 1,000 Pa.s that is endblocked by alkanol at both molecular chain terminals and
(b) diorganopolysiloxane with a viscosity at 25.degree. C. of 0.1 to 1,000 Pa.s that is endblocked at one molecular chain terminal by silanol and at the other terminal by trialkylsiloxy in a molar ratio in the range from 1.0:0.3 to 1.0:3.0 moles of (a) to moles of (b);
(B) 0.1 to 20 weight parts of organosilane with the general formula
R.sup.1.sub.(4-a) Si(OR.sup.2).sub.a
R.sup.1 and R.sup.2 each represent C.sub.1 to C.sub.20 monovalent hydrocarbon groups and a is 3 or 4 or partial hydrolyzate thereof;
(C) 5 to 30 weight parts of organopolysiloxane resin that is solid at ambient temperature and that is composed of the R.sup.3.sub.3 SiO.sub.1/2 and SiO.sub.4/2 units in a molar ratio in the range from 0.5:1.0 to 1.2:1.0 and where R.sup.3 is a C.sub.1 to C.sub.20 monovalent hydrocarbon group or the hydroxyl group
(D) 0.01 to 20 weight parts curing catalyst; and
(E) 0.5 to 10 weight parts diorganopolysiloxane having at least 2 --R.sup.4 --COOR.sup.5 groups in each molecule and having the following general formula ##STR5## wherein R.sup.4 is a divalent hydrocarbon group, R.sup.5 is the hydrogen atom or a monovalent hydrocarbon group, R.sup.6 is a C.sub.1 to C.sub.20 monovalent hydrocarbon group, A is R.sup.6 or --R.sup.4 --COOR.sup.5, k is a positive integer, 1 is 0 or an integer with a value of at least 1, k+1 is at least 10, and k/(1+2)=5/1 to 500/1.

### Claim 9

A method of making a room-temperature-curable silicone elastomer composition comprising (i) mixing
(B) 0.1 to 20 weight parts of organosilane with the general formula
R.sup.1.sub.(4-a) Si(OR.sup.2).sub.a
R.sup.1 and R.sup.2 each represent C.sub.1 to C.sub.20 monolvalent hydrocarbon groups and a is 3 or 4 or partial hydrolyzate thereof;
(C) 5 to 30 weight parts of organopolysiloxane resin that is solid at ambient temperature and that is composed of the R.sup.3.sub.3 SiO.sub.1/2 and SiO.sub.4/2 units in a molar ratio in the range from 0.5:1.0 to 1.2:1.0 and where R.sup.3 is a C.sub.1 to C.sub.20 monovalent hydrocarbon group or the hydroxyl group
(D) 0.01 to 20 weight parts of curing catalyst; and
(E) 0.5 to 10 weight parts of diorganopolysiloxane having at least 2 --R.sup.4 --COOR.sup.5 groups in each molecule and having the following average general formula ##STR6## wherein R.sup.4 is a divalent hydrocarbon group, R.sup.5 is the hydrogen atom or a monovalent hydrocarbon group, R.sup.6 is a C.sub.1 to C.sub.20 monovalent hydrocarbon group, A is R.sup.6 or --R.sup.4 --COOR.sup.5, k is a positive integer, 1 is 0 or an integer with a value of at least 1, k+1 is at least 10, and k/(1+2)=5/1 to 500/1, and (ii) thereafter admixing into the resulting mixture of (i)
(A) 100 weight parts of diorganopolysiloxane composed of
(a) diorganopolysiloxane with a viscosity at 25.degree. C. of 0.02 to 1,000 Pa.s that is endblocked by silanol at both molecular chain terminals and
(b) diorganopolysiloxane with a viscosity at 25.degree. C. of 0.1 to 1,000 Pa.s that is endblocked at one molecular chain terminal by silanol and at the other terminal by trialkylsiloxy in a molar ratio in the range from 1.0:0.3 to 1.0:3.0 moles of (a) to moles of (b).