Room temperature curable organopolysiloxane composition and electric/electronic apparatus
A room temperature curable organopolysiloxane composition comprises: (A) an organopolysiloxane having alkoxysilyl-containing groups at both molecular terminals; (B) an organopolysiloxane resin; (C) an alkoxysilane; and (D) a condensation-reaction catalyst. The room temperature curable organopolysiloxane composition exhibits good to excellent storage stability. In addition, the room temperature curable organopolysiloxane composition can form a cured product exhibiting good to excellent mechanical properties.
1. A room temperature curable organopolysiloxane composition comprising:
(A) about 100 parts by mass of an organopolysiloxane represented by the following general formula:
X—(SiR 1 2 O) m —SiR 1 2 —X;
wherein each R 1 is the same or different monovalent hydrocarbon group lacking an aliphatic unsaturated bond, each X is an alkoxysilyl-containing group selected from the group consisting of a group represented by the following general formula:
—R 3 —SiR 1 a (OR 2 ) (3-a) ,
a group represented by the following general formula;
—R 3 —(SiR 1 2 O) n —SiR 1 2 —R 3 —SiR 1 a (OR 2 ) (3-a) ,
and a group represented by the following general formula;
—R 3 —(SiR 1 2 O) n —SiR 1 b —[OSiR 1 2 —R 3 —SiR 1 a (OR 2 ) (3-a) ] (3-b) ;
wherein each R 1 is as described above, R 2 is an alkyl group, each R 3 is the same or different alkylene group, “a” is 0, 1 or 2, “b” is 0 or 1, “n” is an integer of from 1 to 20, and “in” is an integer of from 50 to 1000;
(B) about 50 to about 200 parts by mass of an organopolysiloxane resin represented by the following average unit formula:
(R 4 3 SiO 1/2 ) c (R 4 2 SiO 2/2 ) d (R 4 SiO 3/2 ) e (ZO 1/2 ) f ;
wherein each R 4 is the same or different monovalent hydrocarbon group, each Z is H or an alkyl group, and “c”, “d” and “e” are numbers satisfied by the following conditions: 0≤c<0.1, 0.3≤d≤0.6, 0.4≤e≤0.7, and c+d+e=1, and wherein “f′ is a number satisfying that the organopolysiloxane resin contains OZ in a range of from about 30 mol % to about 54 mol % based on Si units;
(C) about 0.5 to about 20 parts by mass of an alkoxysilane represented by the following general formula:
R 5 X Si(OR 6 ) (4-x) ;
wherein R 5 is a monovalent hydrocarbon group, R 6 is an alkyl group, and “x” is an integer of from 0 to 2; and
(D) about 0.1 to about 20 parts by mass of a condensation-reaction catalyst.
2. The room temperature curable organopolysiloxane composition according to claim 1 , wherein the alkoxysilyl-containing group in component (A) is a group represented by the following formula:
—C 2 H 4 —Si(CH 3 ) 2 O—Si(CH 3 ) 2 —C 2 H 4 —Si(OCH 3 ) 3 .
3. The room temperature curable organopolysiloxane composition according to claim 2 , wherein component (B) comprises an organopolysiloxane resin represented by the following average unit formula:
[(CH 3 ) 2 SiO 2/2 ] d (CH 3 SiO 3/2 ) e (ZO 1/2 ) f ;
wherein: “d” and “e” are numbers satisfied by the following conditions: 0.3≤d≤0.6, 0.4≤e≤0.7, and d+e=1; each Z is H or an alkyl group; and “f′ is a number satisfying that the organopolysiloxane resin contains OZ in a range of from about 30 mol % to about 54 mol % based on Si units.
4. The room temperature curable organopolysiloxane composition according to claim 3 , wherein component (C) comprises dimethyldimethoxysilane and/or methyltrimethoxysilane.
5. The room temperature curable organopolysiloxane composition according to claim 1 , wherein component (B) comprises an organopolysiloxane resin represented by the following average unit formula:
[(CH 3 ) 2 SiO 2/2 ] d (CH 3 SiO 3/2 ) e (ZO 1/2 ) f ;
wherein: “d” and “e” are numbers satisfied by the following conditions: 0.3≤d≤0.6, 0.4≤e≤0.7, and d+e=1; each Z is H or an alkyl group; and “f′ is a number satisfying that the organopolysiloxane resin contains OZ in a range of from about 30 mol % to about 54 mol % based on Si units.
6. The room temperature curable organopolysiloxane composition according to claim 1 , wherein component (C) comprises dimethyldimethoxysilane and/or methyltrimethoxysilane.
7. The room temperature curable organopolysiloxane composition according to claim 1 , wherein component (B) contains silanol groups.
8. A conformal coating agent comprising the room temperature curable organopolysiloxane composition according to claim 1 .
9. An electric/electronic apparatus obtained by using the room temperature curable organopolysiloxane composition according to claim 1 .
10. The room temperature curable organopolysiloxane composition according to claim 1 , wherein component (B) contains silicon atom-bonded methoxy groups.
11. The room temperature curable organopolysiloxane composition according to claim 1 , wherein the content of component (B) is in a range of from about 80 to about 200 parts by mass, or optionally in a range of from about 100 to about 200 parts by mass, relative to 100 parts by mass of component (A).
12. The room temperature curable organopolysiloxane composition according to claim 1 , wherein the content of component (C) is in a range of front about 0.5 to about 15 parts by mass, or optionally in a range of from about 1 to about 10 part(s) by mass, relative to 100 parts by mass of component (A).
13. The room temperature curable organopolysiloxane composition according to claim 1 , wherein the content of component (D) is in a range of from about 0.1 to about 15 parts by mass, or optionally in a range of from about 1 to about 15 parts by mass, relative to 100 parts by mass of component (A).
14. The room temperature curable organopolysiloxane composition according to claim 1 , wherein component (B) contains silanol groups and silicon atom-bonded methoxy groups.