Crosslinkable polypropylene composition

In producing a crosslinked polypropylene foam, 0.5 to 4 parts by weight of a compound selected from triacrylate and trimethacrylate of aliphatic polyhydric alcohol and a blowing agent are mixed with 100 parts by weight of propylene homopolymer or copolymer. Then, the mixture is shaped under heat, followed by irradiation with an ionizing radiation such that the dose of the radiation absorbed by the shaped mass ranges between 0.1 and 10 Mrad. Finally, the irradiated mass is heated for foaming.

Method of producing crosslinked polypropylene foam

In producing a crosslinked polypropylene foam, 0.5 to 4 parts by weight of a compound selected from triacrylate and trimethacrylate of aliphatic polyhydric alcohol and a blowing agent are mixed with 100 parts by weight of propylene homopolymer or copolymer. Then, the mixture is shaped under heat, followed by irradiation with an ionizing radiation such that the dose of the radiation absorbed by the shaped mass ranges between 0.1 and 10 Mrad. Finally, the irradiated mass is heated for foaming.

Method of crosslinking poly-alpha-olefin series resins

Method of crosslinking poly-α-olefin series resins

A method of crosslinking poly-α-olefin series resins, comprising the steps of subjecting a resin composition to graft reaction under a volume ratio of oxygen to the resin composition set at less than 0.1 and at temperatures ranging between the thermal decomposition temperature of the radical generating agent and 230° C., said composition comprising at least one kind of poly-α-olefin series resin of polypropylene series resin, poly(butene-1) series resin or poly(4-methyl pentene-1) series resin; a radical generating agent of dibenzoyl peroxide or t-butyl perbenzoate; and a silane compound having the general formula of RR'SiY 2 , where "R" is a monovalent olefinically unsaturated hydrocarbon group or hydrocarbonoxy group, "Y" is an organic group capable of hydrolysis, and "R'" is a monovalent hydrocarbon group except aliphatic unsaturated hydrocarbon groups, or the group "Y" or "R" defined above, and bringing the resultant graft polymer into contact with water so as to cause crosslinking reaction under the action of a silanol condensation catalyst added to the reaction system before or after the graft reaction step.

Heat insulating pipe

A heat insulating pipe has a foamed heat insulating layer on its outer circumferential face in which the heat insulating layer has an expansion ratio of at least 4 and is of a three-layered structure consisting of a middle foamed layer and lower and upper foamed layers formed at both sides of the middle foamed layer. The cells of the middle foamed layer are relatively large. The cells of the upper foamed layer and the lower foamed layer are relatively small. The shapes of the cells of the middle foamed layer are such that, for the average cell diameter (μ 1 ) measured in the radial direction of the pipe and the average cell diameter (μ 2 ) measured in the axial direction of the pipe, the relation of μ 1 /μ 2 =0.3-0.9 holds.

Patent JPS6249303B2

Method of crosslinking poly-alpha-olefin resin

Heat insulating pipe

Crosslinking of polyolefin

Patent JPS6356262B2

Production of heat insulating pipe

Process for manufacture of foamed composite material

Method of producing bridged polyolefin moldings

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2 jiseikeiyohatsuhopurasuchitsukufukugobutsu

Process for producing foamed plastic