A preparation process for a solid acrylic resin suitable for a UV curing system is a bulk polymerization method and comprises the steps: adding 100 parts by mass of at least one monofunctional monomer(s) having one polymerizable double bond per molecule, 1-10 parts by mass of one difunctional monomer having two polymerizable double bonds per molecule, 0.1-5.0 parts by mass of an initiator and 1-10 parts by mass of a chain transfer agent to a bulk polymerization reactor capable of water bath heating; homogenizing them by stirring; and then heating the bulk polymerization reactor with a constant temperature water bath at 40-90° C. until the polymerization reaction is completed.

Provided is a novel resin composition for a metal-clad laminate, with which a metal-clad laminate having excellent adhesion with a metal foil, solder heat resistance, insulation and the like can be produced. A terminally modified polybutadiene contained in the resin composition for a metal-clad laminate according to the present invention has a structure of formula (III) on each of both terminals of a polybutadiene comprising a repeating unit of formula (I) and a repeating unit of formula (II), wherein a proportion of the repeating unit of formula (I) in all the repeating units is 70 to 99% by mol.

##STR00001##

Provided is a novel resin composition for a metal-clad laminate, with which a metal-clad laminate having excellent adhesion with a metal foil, solder heat resistance, insulation and the like can be produced. A terminally modified polybutadiene contained in the resin composition for a metal-clad laminate according to the present invention has a structure of formula (III) on each of both terminals of a polybutadiene comprising a repeating unit of formula (I) and a repeating unit of formula (II), wherein a proportion of the repeating unit of formula (I) in all the repeating units is 70 to 99% by mol.

##STR00001##

A method of manufacturing a resin composition includes a step of chemically crosslinking an ionomer (A) of an ethylene-unsaturated carboxylic acid copolymer in the presence of an organic peroxide (B), and a step of melt kneading the chemically crosslinked ionomer (A) and a polyamide resin (C).

A method of manufacturing a resin composition includes a step of chemically crosslinking an ionomer (A) of an ethylene-unsaturated carboxylic acid copolymer in the presence of an organic peroxide (B), and a step of melt kneading the chemically crosslinked ionomer (A) and a polyamide resin (C).

A method of manufacturing a resin composition includes a step of chemically crosslinking an ionomer (A) of an ethylene-unsaturated carboxylic acid copolymer in the presence of an organic peroxide (B), and a step of melt kneading the chemically crosslinked ionomer (A) and a polyamide resin (C).

A crosslinked rubber composition contains a rubber component and para-aramid short fibers having a filament fineness of 2.5 dtex or more and dispersed in the rubber component.

A crosslinked rubber composition contains a rubber component and para-aramid short fibers having a filament fineness of 2.5 dtex or more and dispersed in the rubber component.

An object of the present invention is to provide a golf ball having a decreased spin rate on driver shots. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein the spherical core is formed from a rubber composition containing (a) a base rubber, (b) a compound represented by the formula (1) as a co-crosslinking agent, and (c) a crosslinking initiator,
(R.sup.1COO)M(OCOR.sup.2)m  (1) in the formula (1), M represents a metal atom, m represents 1 or 2, R.sup.1 and R.sup.2 are different from each other, represent an alkenyl group having 2 to 30 carbon atoms or an alkynyl group having 2 to 30 carbon atoms and have a carbon-carbon double bond or a carbon-carbon triple bond at an α-position carbon atom bonding to the carbonyl group, and when m is 2, two of R.sup.2 may be identical to or different from each other.

An object of the present invention is to provide a golf ball having a decreased spin rate on driver shots. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein the spherical core is formed from a rubber composition containing (a) a base rubber, (b) a compound represented by the formula (1) as a co-crosslinking agent, and (c) a crosslinking initiator,
(R.sup.1COO)M(OCOR.sup.2)m  (1) in the formula (1), M represents a metal atom, m represents 1 or 2, R.sup.1 and R.sup.2 are different from each other, represent an alkenyl group having 2 to 30 carbon atoms or an alkynyl group having 2 to 30 carbon atoms and have a carbon-carbon double bond or a carbon-carbon triple bond at an α-position carbon atom bonding to the carbonyl group, and when m is 2, two of R.sup.2 may be identical to or different from each other.