Thermosetting composition for injection molding, method for producing molded article using the same, and cured product

1 . A method for producing a molded article comprising:

supplying a thermosetting composition for injection molding into a plunger, the thermosetting composition for injection molding comprises:

(A) a di(meth)acrylate compound having a structural unit represented by the following formula (A1), and

(B) a thermal polymerization initiator:

wherein in the formula (A1),

V 101 is a substituted or unsubstituted divalent aromatic hydrocarbon group including 6 to 12 ring carbon atoms, a substituted or unsubstituted divalent alicyclic hydrocarbon group including 5 to 12 ring carbon atoms, or a substituted or unsubstituted divalent aliphatic hydrocarbon group including 2 to 30 carbon atoms;

p represents the average number of structural units; and

when p is 2 or more, two or more V 101 's may be the same as or different from each other;

filling the thermosetting composition for injection molding supplied into the plunger into a cavity of a mold using the plunger, the cavity being set to be a gauge pressure of −90 kPa or lower (vacuum pressure 10 kPa) and an oxygen amount of 0.2×cavity volume/22.4 mol or smaller, or to be a gauge pressure of −90 kPa or lower (vacuum pressure 10 kPa) and an oxygen amount of 0.2× cavity volume/22.4 mol or smaller, and

thermosetting the thermosetting composition for injection molding filled into the cavity.

2 . The method for producing a molded article according to claim 1 , wherein a temperature of a part of the mold constituting the cavity is 40 to 150° C.

3 . The method for producing a molded article according to claim 1 , wherein the filling is performed through a flow path between the plunger and the cavity, the flow path being controlled in a temperature at 50° C. or lower.

4 . The method for producing a molded article according to claim 3 , wherein the flow path has a gate system that blocks flow of the thermosetting composition for injection molding and heat transfer.

5 . The method for producing a molded article according to claim 4 , wherein

the filling is performed by opening a gate of the gate system, and

in the step of thermosetting, a pressure holding is performed, and after the pressure holding, the gate of the gate system is closed to complete the thermosetting.

6 . The method for producing a molded article according to claim 1 , wherein the step of filling and the step of thermosetting are performed in 0.2 to 3 minutes.