Insulating-film forming composition, insulating film and preparation process thereof

1. An insulating-film forming composition comprising:

a coating solvent, and

at least one of: (i) a dendrimer having a core portion and a branched end, and (ii) a polymer of the dendrimer;

wherein the dendrimer is represented by formula (1):

wherein R 1 to R 8 each independently represents an alkyl, alkenyl or aryl group or a substituent represented by formula (2) with the proviso that at least one of R 1 to R 8 is a substituent represented by formula (2):

wherein L 1 represents an alkylene group, —O— or —Si(R 11 )(R 12 )— or a divalent linking group which is a combination thereof;

R 11 and R 12 each independently represents an alkyl group;

R 9 represents an alkyl or aryl group; and

i represents an integer of from 1 to 10, and wherein when i represents 1, the substituent represented by formula (2) is A 1 represented by formula (3):

wherein a represents 2 or 3; and

R 10 represents an alkenyl or alkynyl group, with the proviso that where a plurality of L 1 's, R 9 's or R 10 's are present, the plurality of L 1 's, R 9 's or R 10 's may be the same or different; and

the coating solvent is at least one selected from the group consisting of acetone, propanol, cyclohexanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, γ-butyrolactone, anisole, mesitylene and 1,2-dichlorobenzene.

2. The insulating-film forming composition according to claim 1 , wherein the polymerizable group is an ethylenic double bond or an acetylenic triple bond.

3. The insulating-film forming composition according to claim 1 , wherein i represents an integer of from 1 to 5.

4. The insulating-film forming composition according to claim 1 , wherein R 10 represents a vinyl or allyl group.

5. The insulating-film forming composition according to claim 1 , which further comprises a polymerization initiator.

6. An insulating film formed from an insulating-film forming composition according to claim 1 .

7. An electronic device comprising an insulating film according to claim 6 .

8. A process for producing an insulating film, which comprises:

applying an insulating-film forming composition according to claim 1 onto a substrate; and

curing the applied insulating-film forming composition.

9. The insulating-film forming composition according to claim 1 ,wherein the coating solvent is at least one selected from the group consisting of cyclohexanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, γ-butyrolactone and anisole.

10. The insulating-film forming composition according to claim 1 , wherein the variable a represents 3.

11. The insulating-film forming composition according to claim 1 , said composition having a solid concentration of from 5 to 20 mass %.