Carboxylic branched chain-cutting agent for golf ball-covering ionomer resin, golf ball coating composition, and method for manufacturing golf ball
The present invention relates to a carboxylic branched chain-cutting agent for a golf ball-covering ionomer resin, a golf ball coating composition, and a method for manufacturing a golf ball. The present invention can provide a coating composition containing within an appropriate range, a specific compound for use as a carboxylic branched chain-cutting agent for a golf ball-covering ionomer resin, and thus can provide a golf ball on which a bridge is formed between a golf ball covering resin and a coating resin. By providing the coating composition containing a specific composition for use as a carboxylic branched chain-cutting agent for a golf ball-covering ionomer resin, the present invention is appropriate for ensuring the physical properties of the golf ball, such as yellowing resistance, and workability, such as pot life, even eliminating an adhesion pretreatment step, thereby reducing side effects due to the existing pretreatment step while providing a golf ball having excellent physical properties.
1. A method for manufacturing a golf ball, comprising the steps of: manufacturing a golf ball core, manufacturing an ionomer cover surrounding the core, grinding a mold seam of the cover, a top coating, and a drying, wherein the step of the top coating uses a top coating composition, wherein the method does not include a step of an adhesion pretreatment onto the surface of the cover,
wherein the top coating composition comprises a carboxylic branched chain cleavage agent of a golf ball cover ionomer resin, a crosslinker and a coating resin,
wherein the carboxylic branched chain cleavage agent comprises a compound represented by the following formula 1:
wherein R1 and R2 are each independently selected from the group consisting of H, C 1-10 alkyl, C 5 -C 15 aralkyl, C 6 -C 16 aryl, and
wherein the carboxylic branched chain cleavage agent comprises 1 to 3.5 parts by weight for 100 parts by weight of the coating resin and solvent,
wherein the crosslinker is N,N′-(methylenedi-p-phenylene)bis(aziridine-1-carboxamide), as an amount of 1 to 150 parts by weight based on 100 parts by weight of the carboxylic branched chain cleavage agent of the golf ball cover ionomer resin,
wherein the golf ball cover ionomer resin is one or more selected from the group consisting of a hard ionomer which is a magnesium, lithium, sodium or zinc salt of a copolymer of ethylene with methacrylic acid, and a soft ionomer which is a sodium salt of a terpolymer of n-butyl acrylate or iso-butyl acrylate, ethylene and methacrylic acid,
wherein the coating resin is selected from the group consisting of a two-component urethane resin, a two-component acrylic urethane resin and a PVC resin, and
wherein the drying step is performed by near infrared (NIR) drying.
2. The method of claim 1 , further comprising a step of marking prior to the step of the top coating.
3. The method of claim 1 , wherein the step of manufacturing the cover comprises a step of overlapping one to four cover over-layers around the core to provide two-piece to five-piece golf balls.
4. The method of claim 1 , wherein the step of the top coating is performed by air-spray coating or electrostatic coating.
5. A golf ball which is manufactured by the method of claim 1 , wherein the golf ball has a coating layer formed onto the surface of the golf ball, wherein the coating layer has a structure in which a bridge is formed between a cover resin constituting the surface parts of the golf ball and a coating resin.
6. The golf ball of claim 5 , wherein the coating layer has a thickness of 5 to 50 μm.