A method of molding polymerizable composition comprising lactam monomer, catalyst and initiator

Claim 1

In a method of molding, comprising: (I) depositing in a mold a charge of a polymerizable composition, comprising lactam monomer, initiator, and catalyst; (II) polymerizing the charge while in the mold so as to form an at least partially cured article; (III) removing the article from the mold, wherein the improvement comprises utilizing as the initiator and catalyst components a Grignard catalyst for lactam polymerization and an initiator system comprising: (a) at least one material represented by the following structural formula: ##STR22## (b) at least one material represented by the following structural formula: ##STR23## wherein q and v are independently an integer of at least 1; Z and W are independently selected from a compound or polymeric material, said compound being composed of at least two elements in chemical combination which contain up to two repeating structural units, said polymeric material being a macromolecule formed by the chemical union of at least two coreactants and having at least three repeating structural units; with the proviso that at least a portion of either or both the materials (a) or (b) is a polymeric material; R, R', R", R"' are independently hydrogen, a C 1 to C 10 aliphatic radical, C 3 to C 10 cycloaliphatic radical, C 6 to C 10 aryl or alkaryl radical, and independently R and R" and the carbon to which each is attached are included as part of a cycloaliphatic or aromatic ring; and Y is an alkylene group having from 3 to 12 carbon atoms or an alkylene group having from 3 to 12 carbon atoms interrupted by a heteroatom; with the proviso that the equivalent ratio ##STR24## groups to the magnesium of the Grignard catalyst is within the range of from 0.3 to 1 to 4 to 1, and at least 10 percent of the initiator groups of the initiator system are of the (a) type.