Abstract: Method for the preparation of a foam polyamide in which the lactam together with a basic catalyst at a temperature above the melting point of the lactam is mixed with the promoter and foaming agent in a mixing vessel at ambient temperature while subjecting the mix to violent agitation to initiate polymerization, and the mix is discharged into a container for completion of the reaction before polymerization is more than 10% complete.

Abstract: Methods of preparing polyamide foam comprising polymerizing and foaming a mixture of one or more specified lactams, a basic alkali metal lactam catalyst, an alkyl isocyanate activator and a foaming agent at a temperature above the melting point of the lactam, and below the melting point of the polyamide foam thus produced.

Abstract: A vulcanizable rubber composition suitable for the production of rubber materials having improved scorching stability and heat aging resistance can be obtained by compounding raw material rubber with a sulfenamide compound having the following general formula ##EQU1## wherein X represents a residue selected from the group consisting of residues of hydrocarbon, alkyl ether and secondary alcohol having 2-20 carbon atoms, and residues represented by the general formulae ##EQU2## (wherein R' represents a residue of hydrocarbon or alkyl ether having 0-20 carbon atoms, and R" represents a hydrocarbon residue having 1-10 carbon atoms), and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are same or different and are selected from hydrocarbon residues having 2-10 carbon atoms, and hydrogen atom, or R.sub.1 is ringed with R.sub.2 and/or R.sub.3 is ringed with R.sub.4, through the nitrogen atom of the general formula (1), to form heterocyclic rings of 5-7 members.

Abstract: This invention relates to an improvement of the adhesion of a metallic material such as copper, copper alloys and other metals coated therewith with a vulcanizable rubber composition. It is realized by previously adding orthoboric acid or a metal borate to the rubber composition in order to proceed with metal-rubber bonding reaction and vulcanization reaction in good balance, and vulcanizing an assembly of the metallic material and the boric compound containing rubber composition closely contacted therewith.