Abstract: By completing curing in a short period of time even at low temperatures and using an epoxy resin composition as a matrix resin of a prepreg, it is possible to obtain a fiber-reinforced composite plastic product such as a fiber-reinforced tubular composite with excellent mechanical properties and, more particularly, excellent impact resistance. The epoxy resin composition includes A component, B component, C component, D component and E component, where the content rate of sulfur atoms is equal to or more than 0.2 wt % and equal to or less than 7 wt %, and the content rate of the C component is equal to or more than 1 wt % and equal to or less than 15 wt %. A component: epoxy resins, B component: reactive products of the epoxy resins and an amine compounds including the sulfur atom in a molecule (the unreacted epoxy resins and/or the amine compounds may be included), C component: polyamide compounds soluble in the A component, D component: urea compounds, and E component: dicyandiamide.

Abstract: A shaft for a golf club comprises a plurality of fiber-reinforced resin layers. A plurality of circumferentially oriented metal wires are provided at intervals of 1 mm to 4 mm in an axial direction of the shaft having a length in an axial direction of more than 100 mm and less than 300 mm and being centered at a position of 3.25×102 mm from a larger-diameter end of the shaft.

Abstract: Disclosed is a golf club head which enables to improve a direction of a hit ball while assuring a carry and run of the ball corresponding to a head speed and a position at which the ball is hit on a face part, and enables to assure a stable direction of a hit ball while realizing a stable carry and run of the ball even if the ball is hit at a position other than the sweet spot.

Abstract: By completing curing in a short period of time even at low temperatures and using an epoxy resin composition as a matrix resin of a prepreg, it is possible to obtain a fiber-reinforced composite plastic product such as a fiber-reinforced tubular composite with excellent mechanical properties and, more particularly, excellent impact resistance. The epoxy resin composition includes A component, B component, C component, D component and E component, where the content rate of sulfur atoms is equal to or more than 0.2 wt % and equal to or less than 7 wt %, and the content rate of the C component is equal to or more than 1 wt % and equal to or less than 15 wt %. A component: epoxy resins, B component: reactive products of the epoxy resins and an amine compounds including the sulfur atom in a molecule (the unreacted epoxy resins and/or the amine compounds may be included), C component: polyamide compounds soluble in the A component, D component: urea compounds, and E component: dicyandiamide.

Abstract: A shaft for a golf club comprises a plurality of fiber-reinforced resin layers. A plurality of circumferentially oriented metal wires are provided at intervals of 1 mm to 4 mm in an axial direction of the shaft having a length in an axial direction of more than 100 mm and less than 300 mm and being centered at a position of 3.25×102 mm from a larger-diameter end of the shaft.

Abstract: The present invention relates to a process for a production of fiber-reinforced plastic tubing on a cored bar. Therefore, according to the invention, a fiber-reinforced plastic intermediate material obtained by laminating plural fiber-reinforced plastic intermediate material layers one after another is put and sealed in a bag-like membrane material, an inside of the membrane material is depressurized and then the fiber-reinforced intermediate material is taken out of the bag-like membrane material and wound around the cored bar to mold the FRP tubing.

Abstract: A golf club shaft is 35-50 percent lighter than a conventional shaft while maintaining the outer diameter and structural characteristics of conventional shafts. The shaft has at least four layers of fiber reinforced material. The fiber reinforced layers are from innermost to outermost: a first angled layer; a first straight layer; a second angled layer; and a second straight layer. The angled layers are formed by bonding together two materials, each with fibers aligned in different directions. The second angled layer maintains the proper strength and rigidity of the shaft while keeping the shaft as light weight as possible. Aligning the second layer's fibers at an angle of 35-75 degrees with respect to the longitudinal direction of the shaft ensures proper weight and strength characteristics of the shaft. The resulting shaft is light-weight and exhibits the flexural rigidity, flexural strength, torsional rigidity, torsional strength, and crushing strength of conventional shafts.

Abstract: The present invention relates to a process for a production of fiber-reinforced plastic tubing on a cored bar. Therefore, according to the invention, a fiber-reinforced plastic intermediate material obtained by laminating plural fiber-reinforced plastic intermediate material layers one after another is put and sealed in a bag-like membrane material, an inside of the membrane material is depressurized and then the fiber-reinforced intermediate material is taken out of the bag-like membrane material and wound around the cored bar to mold the FRP tubing.

Abstract: A golf club shaft is 35-50 percent lighter than a conventional shaft while maintaining the outer diameter and structural characteristics of conventional shafts. The shaft has at least four layers of fiber reinforced material. The fiber reinforced layers are from innermost to outermost: a first angled layer; a first straight layer; a second angled layer; and a second straight layer. The angled layers are formed by bonding together two materials, each with fibers aligned in different directions. The second angled layer maintains the proper strength and rigidity of the shaft while keeping the shaft as light weight as possible. Aligning the second layer's fibers at an angle of 35-75 degrees with respect to the longitudinal direction of the shaft ensures proper weight and strength characteristics of the shaft. The resulting shaft is light-weight and exhibits the flexural rigidity, flexural strength, torsional rigidity, torsional strength, and crushing strength of conventional shafts.

Abstract: A golf club shaft having an optimal set of materials and sloped sections provides appropriately high rigidity, ease of use, and is inexpensive and easy to manufacture. A sloped section expands toward a grip end of the shaft. The sloped section has a slope gradient from 15/1000 to 35/1000 and a length from 200 to 350 mm. The outer diameter of the grip end is from 18 to 25 mm. On the side of the sloped section toward an end, there is formed a semi-sloped section with a slope gradient from 4/1000 to 13/1000. A kick point is formed at a position from 40% to 46% from the small-diameter end relative to the total shaft length. The number of required parts is small while production is simple. The shaft is light, has appropriate hardness, and high rigidity at the grip. Furthermore, the strength of the shaft is balanced and provides a good feel when hitting a ball. Production of the golf club shaft can be accomplished with standard materials such as fiber-reinforced resins.

Abstract: A golf club shaft and a method especially suited for producing the shaft that provides appropriately high rigidity and ease of use and that allows inexpensive and easy manufacture.

Abstract: A golf club shaft is 35-50 percent lighter than a conventional shaft while maintaining the outer diameter and structural characteristics of conventional shafts. The shaft has at least four layers of fiber reinforced material. The fiber reinforced layers are from innermost to outermost: a first angled layer; a first straight layer; a second angled layer; and a second straight layer. The angled layers are formed by bonding together two materials, each with fibers aligned in different directions. The second angled layer maintains the proper strength and rigidity of the shaft while keeping the shaft as light weight as possible. Aligning the second layer's fibers at an angle of 35-75 degrees with respect to the longitudinal direction of the shaft ensures proper weight and strength characteristics of the shaft. The resulting shaft is light-weight and exhibits the flexural rigidity, flexural strength, torsional rigidity, torsional strength, and crushing strength of conventional shafts.