Photocurable fluorinated copolymer composition

Production of Fluorinated Copolymer (A-1))

[0191]Into a stainless steel autoclave having an internal capacity of 300 ml and equipped with a stirrer, 3-ethyl-3-vinyloxymethyloxetane (22.4 g) to form the units (a-2), hydroxybutyl vinyl ether (9.1 g) to form the units (a-3), cyclohexyl vinyl ether (19.8 g) to form the units (a-4), xylene (95.0 g), ethanol (17.7 g) and potassium carbonate (1.0 g) were introduced all at once, and dissolved oxygen was removed by nitrogen.

[0192]Then, chlorotrifluoroethylene (45.8 g) to form the units (a-1) was introduced into the autoclave, the temperature was gradually raised, and when it reached 55° C., a xylene solution (0.6 g) containing 50% of t-butyl peroxypivalate was introduced into the autoclave over a period of two hours, followed by further stirring for 15 hours, whereupon the reaction was terminated. After the reaction, potassium carbonate was removed by filtration, and ethanol and a part of xylene were distilled off by evaporation so that a non-vo

Production of Fluorinated Copolymer (A-2))

[0195]Into a stainless steel autoclave having an internal capacity of 300 ml and equipped with a stirrer, 3-ethyl-3-vinyloxymethyloxetane (33.6 g) to form the units (a-2), hydroxybutyl vinyl ether (9.1 g) to form the units (a-3), cyclohexyl vinyl ether (9.9 g) to form the units (a-4), xylene (95.0 g), ethanol (17.7 g) and potassium carbonate (1.0 g) were introduced all at once, and dissolved oxygen was removed by nitrogen.

[0196]Then, chlorotrifluoroethylene (45.8 g) to form the units (a-1) was introduced into the autoclave, the temperature was gradually raised, and after it reached 55° C., a xylene solution (0.6 g) containing 50% of t-butyl peroxypivalate was introduced into the autoclave over a period of two hours, followed by further stirring for 15 hours, whereupon the reaction was terminated. After the reaction, potassium carbonate was removed by filtration, and ethanol and a part of xylene were distilled off by evaporation so that a non-vo

Production of Fluorinated Copolymer (A-3))

[0199]The fluorinated copolymer (A-2) (200.0 g) obtained in Production Example 2 was transferred to a four-necked flask having a capacity of 500 ml and equipped with a thermometer, a reflux condenser and a stirrer, and 3-isocyanate propyltriethoxysilane (27.6 g), xylene (33.5 g) and tin 2-ethylhexanoate (0.04 g) were added, followed by a reaction at 50° C. for 5 hours in a nitrogen atmosphere.

[0200]The infrared absorption spectrum of the obtained solution was measured, whereby no absorption peak was observed in the absorption band of an isocyanate group, and instead, a large absorption peak was observed in the absorption band of an urethane bond. Thus, formation of the fluorinated copolymer (A-3) having alkoxysilyl groups was confirmed.

[0201]After the reaction, trimethyl orthoformate (8.6 g) and isopropanol (8.6 g) were added, and adjustment was made so that a non-volatile component of the fluorinated copolymer (A-3) would be 60%.

[0202]From H1-