The object of the present invention is to provide a golf ball having excellent durability and resilience. The present invention provides a golf ball which includes a core, and a cover covering the core. The cover contains an ionomer resin and an organically modified layered silicate. The organically modified layered silicate has an interlayer distance, measured by X-ray diffraction, in a range from 2.5 nm to 15 nm.
1. A golf ball comprising a core and a cover covering the core, wherein
the cover contains an ionomer resin and an organically modified layered silicate, and
the organically modified layered silicate has an interlayer distance, measured by X-ray diffraction after molding into the cover, in a range from 2.5 nm to 15 nm.
2. The golf ball according to claim 1 , wherein the organically modified layered silicate has an interlayer distance, measured by X-ray diffraction, in a range from 2.6 nm to 14.5 nm.
3. The golf ball according to claim 1 , wherein the organically modified layered silicate has an interlayer distance, measured by X-ray diffraction, in a range from 2.7 nm to 14.0 nm.
4. The golf ball according to claim 1 , wherein the ionomer resin has a melt flow rate (190° C., 2.16 kg) in a range from 0.5 g/10 min to 15 g/10 min.
5. The golf ball according to claim 1 , wherein the ionomer resin has a melt flow rate (190° C., 2.16 kg) in a range from 2.0 g/10 min to 13 g/10 min.
6. The golf ball according to claim 1 , wherein the content of the organically modified layered silicate in the cover is in a range from 0.01 part by mass to 10 parts by mass with respect to 100 parts by mass of the ionomer resin.
7. The golf ball according to claim 1 , wherein the organically modified layered silicate is a layered silicate organically modified by an organic ammonium ion.
8. The golf ball according to claim 7 , wherein the layered silicate is at least one selected from a smectite group consisting of montmorillonite, beidellite, nontronite, saponite, ferrous saponite, hectorite, sauconite, and stevensite.
9. The golf ball according to claim 1 , wherein the cover has a slab hardness in Shore D Hardness in a range from 40 to 80.
10. A golf ball comprising a core and a cover covering the core, wherein
the cover contains
an ionomer resin having a melt flow rate (190° C., 2.16 kg) in a range from 0.5 g/10 min to 15 g/10 min, and
an organically modified layered silicate which is obtained by modifying a layered silicate selected from a smectite group consisting of montmorillonite, beidellite, nontronite, saponite, ferrous saponite, hectorite, sauconite, and stevensite by an organic ammonium ion and which has an interlayer distance, measured by X-ray diffraction after molding into the cover, in a range from 2.5 nm to 15 nm.
11. A method for producing a golf ball, comprising the steps of:
organically modifying a layered silicate by an organic cation to produce an organically modified layered silicate;
mixing the organically modified layered silicate and the ionomer resin to prepare a nanocomposite having an interlayer distance in a range from 2.0 nm to 15 nm before the coverforming step; and
forming a cover such that the organically modified layered silicate in the cover has an interlayer distance, measured by X-ray diffraction after molding into the cover, in a range from 2.5 nm to 15 nm, by using nanocomposite and an additive.
12. The method according to claim 11 , wherein the organically modified layered silicate and the ionomer resin are mixed by using a twin screw extruder at the mixing step, under a mixing condition of a mixing temperature in a range from 140° C. to 220° C.
13. The method according to claim 11 , wherein at the cover forming step, the nanocomposite and the additive are mixed and injection-molding of the cover is conducted, both by using a twin-screw extruder at a mixing temperature in a range from 140° C. to 220° C.