Abstract: The novel polyfunctional peroxides are compounds represented by the following general formula (1):R.sup.1 -CX.sub.3 ( 1)wherein R.sup.1 represents a linear alkyl group having 1 to 3 carbon atoms; and X represents a group: ##STR1## (wherein R.sup.2 represents a linear or branched alkyl group having 1 to 5 carbon atoms). Such polyfunctional peroxides include 1,1,1-tris(t-butylperoxycarbonyloxymethyl)propane and the like. The polymerization initiators for vinyl monomers comprise such polyfunctional peroxides. In the process for polymerizing vinyl monomers, a vinyl monomer is polymerized employing such polyfunctional peroxide at 60 to 160.degree. C.

Abstract: The novel polyfunctional peroxides are compounds represented by the following general formula (1):R.sup.1 --CX.sub.3 (1)wherein R.sup.1 represents a linear alkyl group having 1 to 3 carbon atoms; and X represents a group: ##STR1## (wherein R.sup.2 represents a linear or branched alkyl group having 1 to 5 carbon atoms).Such polyfunctional peroxides include 1,1,1-tris(t-butylperoxycarbonyloxymethyl)propane and the like. The polymerization initiators for vinyl monomers comprise such polyfunctional peroxides. In the process for polymerizing vinyl monomers, a vinyl monomer is polymerized employing such polyfunctional peroxide at 60 to 160.degree. C.

Abstract: A vulcanizable rubber composition which contains an iodine- or bromine-containing rubber and an organic peroxide of the formula. ##STR1## wherein R.sup.1 is a hydrogen atom, a chlorine atom or methyl group, R.sup.2 is a linear or branched alkyl group having 2 to 5 carbon atoms, and n is an integer of 1 to 3, generates only a small amount of methyl iodide or methyl bromide during the vulcanization.

Abstract: A composition for cross-linking of ethylene.polymer comprises 2,4-diphenyl-4-methyl-1-pentene and at least one peroxide selected from the group consisting of [1] peroxides represented by the formula (I): ##STR1## (wherein R.sup.1 stands for one member selected from the group consisting of alkyl groups, aryl groups, and alkyl-substituted aryl groups having 1 to 9 carbon atoms, R.sup.2 for one member selected from the group consisting of phenylene group, ethylene group, --C.tbd.C--, and alkyl groups, aryl groups, and alkyl-substituted aryl groups having 1 to 9 carbon atoms, and n for 1 or 2) and [2] peroxides represented by the formula (II): ##STR2## (wherein two R.sup.3 's independently stand for one member selected from the group consisting of alkyl groups, aryl groups, and alkyl-substituted aryl groups of 1 to 9 carbon atoms or jointly stand for an ethylene group, R.sup.4 and R.sup.5 independently stand for a linear or branched alkyl group of 1 to 6 carbon atoms or --(CH.sub.2).sub.m C(O)OR.sup.6 [wherein R.

Abstract: A vulcanizable rubber composition which contains an iodine- or bromine-containing rubber and an organic peroxide of the formula: ##STR1## wherein R.sup.1 is a hydrogen atom, a chlorine atoms or methyl group, R.sup.2 is a linear or branched alkyl group having 2 to 5 carbon atoms, and n is an integer of 1 to 3, generates only a small amount of methyl iodide or methyl bromide during the vulcanization.

Abstract: An ester type polymeric peroxide; has a peroxide group of the formula (I): ##STR1## a group of the formula (I') ##STR2## a group of the formula (II) ##STR3## wherein X stands for one member selected from the group consisting of --CH.sub.2 --CH.sub.2 --, --C.tbd.C-- and ##STR4## continuously bound such that I and I' occur randomly in alternation with II, having a (I):(I') molar ratio in the range of from 9:1 to 1:9 and the [(I)+(I')]:(II) molar ratio in the range of from 6:4 to 4:6, and having an average molecular weight in the range of from 1,000 to 20,000, a polymerization initiator for vinyl type monomer comprising said ester type polymeric peroxide and method for the production of a block copolymer of vinyl type monomer by said polymerization initiator.

Abstract: A composition for cross linking an ethylene polymer comprises an organic peroxide as a cross linking agent and a compound represented by the formula: ##STR1## wherein R stands for a hydrogen atom or one member selected from the class consisting of alkyl groups of 1 to 9 carbon atoms and n is an integer of 2 or 3. A method for cross linking the ethylene type polymer uses the composition mentioned above. An electric power cable comprises a core coated with resinous layers produced by the method described above.

Abstract: A polymeric peroxy ester, which consists of a structural unit represented by the formula (I): ##STR1## and a structural unit represented by the general formula (II): ##STR2## wherein R represents --CH.sub.2 CH.sub.2 --, --C.tbd.C-- or ##STR3## and had an average molecular weight or 1,000-15,000, said structural units (I) and (II) being bonded alternately in a molar ratio within the range of from 6:4 to 4:6, has a 10-hour half-life period temperature of 70.degree.-85.degree. C. and a high activity at relatively high temperature, is safe in the production and handling, is adapted to be used as a polymerization initiator in the polymerization of vinyl monomer, and can produce a vinyl polymer having a high molecular weight.

Abstract: Expandable thermoplastic resin particles comprising a thermoplastic resin and a hydrocarbon having the lower boiling point than the softening point of the thermoplastic resin in which a copolymer composed of a fluorinated vinyl polymer part and a hydrophilic vinyl polymer part covers or is included on the surface or in the surface layer of the expandable thermoplastic particle, said resin particles are useful for producing package vessels and containers for oily or fatty foods.