초록 ▼

In transfer molding thermosetting polymeric materials, a first preform of first thermosetting polymeric material having a volume substantially equal to the volume of the die cavities is placed in the transfer chamber adjacent the runners. A second preform of second thermosetting polymeric material c

In transfer molding thermosetting polymeric materials, a first preform of first thermosetting polymeric material having a volume substantially equal to the volume of the die cavities is placed in the transfer chamber adjacent the runners. A second preform of second thermosetting polymeric material cheaper than the first polymeric material is placed in the transfer chamber above the first preform. The transfer chamber is pressurized and the second preform is deformed and pressurizes and deforms the first preform and causes the first thermosetting polymeric material to flow through the runners into the die cavities. After curing, the molded articles consisting of first thermosetting polymeric material are removed from the die cavity, and scrap cull and runner consisting substantially of cheap second thermosetting polymeric material are removed from the mold runners and the bottom of the transfer chamber. Thus, considerable economies are effected. The material of the second preform is selected for certain physical properties. Various means are shown for loading the transfer chamber.

대표청구항 ▼

Method of filling a die cavity with a thermosetting polymeric first material through a runner from a chamber to produce a molded article, said method comprising: a. forming a slug adjacent to said chamber said slug consisting of a first body of said first material at one longitudinal end thereof, of

Method of filling a die cavity with a thermosetting polymeric first material through a runner from a chamber to produce a molded article, said method comprising: a. forming a slug adjacent to said chamber said slug consisting of a first body of said first material at one longitudinal end thereof, of a volume at least equal to the volume of the die cavity, and a second body of a second material at the opposite longitudinal end thereof, said first and second bodies having a transversely extending interface intermediate the two longitudinal ends of said slug, by extending said first material and said second material longitudinally toward each other and into engagement with each other at said transversely extending interface, so as to form a combined structure, and cutting off a length of said combined structure including said transversely extending interface; b. heating said die cavity; c. introducing said slug into said chamber oriented with respect thereto so that said first body of first material is adjacent to said runner; and d. pressurizing and deforming said slug in said chamber sufficiently so that said second material forces said first material to flow from said chamber and through said runner so as to fill said die cavity, with at least a portion of said second material flowing from said chamber into said runner.