CPC C08F 255/02 (2013.01) [C08J 3/24 (2013.01); C08J 9/142 (2013.01); C08J 2203/12 (2013.01); C08J 2323/26 (2013.01)] | 7 Claims |
1. A method of producing extruded polypropylene-based resin particles, the method comprising:
a first step of producing an extruded expanded article by an extrusion expansion method with (a) a modified polypropylene resin and (b) a carbonic acid gas serving as a blowing agent; and
a second step of producing extruded expanded particles by cutting the extruded expanded article, obtained in the first step, in a particle shape,
wherein the (a) modified polypropylene resin is obtained by melting and kneading a random polypropylene resin, a conjugated diene compound, and a radical polymerization initiator to obtain a modified polypropylene resin,
the random polypropylene resin containing an ethylene unit in an amount of more than 0.0% by weight and not more than 2.5% by weight with respect to 100 parts by weight of the random polypropylene resin, and wherein the random polypropylene resin has a melt flow rate (MFR) of not less than 5.0 g/10 minutes and not more than 20.0 g/10 minutes,
the conjugated diene compound blended in the melting and kneading comprises not less than 0.01 parts by weight and not more than 5.00 parts by weight with respect to 100 parts by weight of the random polypropylene resin,
the radical polymerization initiator blended in the melting and kneading comprises not less than 0.01 parts by weight and not more than 5.00 parts by weight with respect to 100 parts by weight of the random polypropylene resin,
wherein the radical polymerization initiator is a mixture containing at least one kind of organic peroxide (A) having a structure represented by the following Formula (1) and at least one kind of organic peroxide (B) having at least one structure represented by the following Formula (4) or (5),
wherein each of the at least one kind of organic peroxide (A) and the at least one kind of organic peroxide (B) have a ten-hour half-life temperature of 90° C. to 150° C.,
![]() where: R1, R8, R9, and R13 are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and are optionally identical to or different from each other;
R2 is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 8 carbon atoms;
R10 and R11 (a) are each independently a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and are optionally identical to or different from each other or (b) form a substituted or unsubstituted cycloalkyl group having 3 to 8 carbon atoms together; and
R12 is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and
wherein when subjected to extraction in p-xylene at 130° C. for 6 hours with use of a metal gauze having a mesh size of 37 μm (400-mesh metal gauze), the modified polypropylene resin has a gel fraction of not less than 0.5% by weight and not more than 1.5% by weight with respect to 100% by weight of the modified polypropylene resin.
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