Provided is a rubber composition having excellent adhesiveness to a metal member even if no cobalt salt is contained. The rubber composition contains a rubber component, a rubber-metal adhesion promoter containing Bi, and an organic acid salt of metal other than Bi, where a content of metal element other than Bi with respect to a content of Bi element (content of metal element other than Bi/content of Bi element) in the rubber composition is more than 14 and 100 or less in terms of molar ratio, a content of the rubber-metal adhesion promoter is more than 1.5 parts by mass with respect to 100 parts by mass of the rubber component, and the amount of substance of metal element other than Bi contained in the organic acid salt of metal other than Bi in the rubber composition is 0.01 mol or more.

A resin composition containing: a thermoplastic resin (A) that does not contain a polar group; a thermoplastic resin (B) that contains a polar group; an ethylene-vinyl alcohol copolymer (C) having an ethylene content of 20 to 60 mol %; an aliphatic carboxylic acid (D) having 3 or more carbon atoms; and an aliphatic carboxylic acid metal salt (E) that is a metal salt of the aliphatic carboxylic acid (D), wherein a metal species of (E) is at least one selected from the group consisting of elements belonging to the fourth period d-block in the long periodic table, the content of (A) is 66 to 99 wt. % with respect to the total sum of contents of the resin composition, and the content of (C) is 0.1 to 25 wt. % with respect to the total sum of the contents of the resin composition.

A resin composition containing: a thermoplastic resin (A) that does not contain a polar group; a thermoplastic resin (B) that contains a polar group; an ethylene-vinyl alcohol copolymer (C) having an ethylene content of 20 to 60 mol %; an aliphatic carboxylic acid (D) having 3 or more carbon atoms; and an aliphatic carboxylic acid metal salt (E) that is a metal salt of the aliphatic carboxylic acid (D), wherein a metal species of (E) is at least one selected from the group consisting of elements belonging to the fourth period d-block in the long periodic table, the content of (A) is 66 to 99 wt. % with respect to the total sum of contents of the resin composition, and the content of (C) is 0.1 to 25 wt. % with respect to the total sum of the contents of the resin composition.

A method for producing a polyvinyl alcohol resin having an absorbance of not less than 0.2 at 280 nm, which includes: melt-kneading a polyvinyl alcohol resin material; extruding the resulting melt-kneaded polyvinyl alcohol resin into a sheet; cooling the resulting polyvinyl alcohol resin sheet; and pulverizing the cooled polyvinyl alcohol resin sheet. The method ensures a higher productivity and an excellent long-run property.

A method for producing a polyvinyl alcohol resin having an absorbance of not less than 0.2 at 280 nm, which includes: melt-kneading a polyvinyl alcohol resin material; extruding the resulting melt-kneaded polyvinyl alcohol resin into a sheet; cooling the resulting polyvinyl alcohol resin sheet; and pulverizing the cooled polyvinyl alcohol resin sheet. The method ensures a higher productivity and an excellent long-run property.

There is provided a co-injection molded multilayer structure comprising a barrier layer and outer layers laminated to contact with the barrier layer on its both sides, wherein the barrier layer is made of a resin composition (X) comprising an ethylene-vinyl alcohol copolymer (A) and an alkali metal salt (B) of a higher fatty acid, having a melting point of 250° C. or lower; the ethylene-vinyl alcohol copolymer (A) has an ethylene unit content of 20 to 60 mol % and a saponification degree of 90% or more, and a content of the alkali metal salt (B) in the barrier layer is 50 to 1500 ppm in terms of metal atoms; and the outer layers are made of a resin composition (Y) comprising an unmodified high-density polyethylene (F) and a maleic anhydride-modified polyethylene (G), and a maleic anhydride modification rate relative to the whole resin composition (Y) is 0.005 to 0.1 wt %. This co-injection molded multilayer structure has excellent adhesiveness, so that its oxygen barrier performance can be maintained even after being subjected to an impact due to falling or the like.

There is provided a co-injection molded multilayer structure comprising a barrier layer and outer layers laminated to contact with the barrier layer on its both sides, wherein the barrier layer is made of a resin composition (X) comprising an ethylene-vinyl alcohol copolymer (A) and an alkali metal salt (B) of a higher fatty acid, having a melting point of 250° C. or lower; the ethylene-vinyl alcohol copolymer (A) has an ethylene unit content of 20 to 60 mol % and a saponification degree of 90% or more, and a content of the alkali metal salt (B) in the barrier layer is 50 to 1500 ppm in terms of metal atoms; and the outer layers are made of a resin composition (Y) comprising an unmodified high-density polyethylene (F) and a maleic anhydride-modified polyethylene (G), and a maleic anhydride modification rate relative to the whole resin composition (Y) is 0.005 to 0.1 wt %. This co-injection molded multilayer structure has excellent adhesiveness, so that its oxygen barrier performance can be maintained even after being subjected to an impact due to falling or the like.

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.

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.