JPH03132313A - Method of molding hollow body - Google Patents

Abstract

PURPOSE:To enable a complicated configuration to be molded and improve considerably the performance of an article by covering and heat-curing the circumference of a core, which is a solid substance consisting of sand solidified by an adhesive agent, with a thermosetting compound material and then remov ing the core with water or alkaline water. CONSTITUTION:About 97pts.wt. of Flattery's silica sand and about 3 pts.wt. of a binder are kneaded and a solid substance is made which is smaller than a golf club head by about 8 mm from the face surface and by about 2.5 - 3 mm in other surfaces for employing this as a core. And, the core is placed in a molding mold and SMC consisting of epoxy resin and about 12 mm of carbon fiber is average is disposed in the outer circumference thereof and then subjected to heating and pressure-molding. After the demolding, the FRP layer below the head is hollowed out by about 2 cm<2> - 3 cm<2> and then steeped in alkaline solution and thus the sand in the core is destroyed and extracted there from for making a hollow FRP golf club heat. The sand used as a core has an excellent heat resistivity and pressure resistivity and therefore it is possible to apply sufficiently molding pressure thereon, with the result that the filling defects and inner cracks can be prevented completely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel method for molding hollow bodies made of composite materials.

[Prior art and problems to be solved by the invention] Hollowness and weight reduction using thermosetting composite materials have conventionally been achieved by using low melting point alloys, molded products using glass balloons, thermoplastic resin foams, etc. It was done.

However, conventionally used low-melting point alloys are difficult to handle and safe, and molded products using glass balloons or thermoplastic resin foams have low pressure resistance, and filling failures occur because sufficient molding pressure cannot be applied. There were problems with changes in wall thickness. The present invention provides a molding method that solves the problems of the conventional methods.

[Means to solve the problem]

That is, the gist of the present invention is that when a hollow body is deformed using a thermosetting composite material, the periphery of a core made of a solid material made of sand hardened with a binder is covered with the thermosetting composite material and then heated and hardened. The method for molding a hollow body is characterized in that after molding, the core is removed with water or alkaline water.

The binder used in the present invention is a type of binder, and is used for molding cast metal.

For example, a binder that uses an aqueous solution of an alkaline resol type phenolic resin as a main ingredient and a liquid composite composition of an organic acid ester as a curing agent can be mentioned. Further, the sand used in the present invention is preferably ordinary foundry sand. The type of sand can affect curing characteristics and waiting time.

The composition is not particularly limited, but 1 to 5 parts by weight of the main agent to 100 parts by weight of sand, and 10 to 5 parts by weight of the hardening agent to the main agent.
It is preferable to blend 0 parts by weight. In the present invention, in order to cover the core with a thermosetting composite material (hereinafter sometimes abbreviated as PRP) and heat-cure it,
Compression molding, transfer molding, injection molding, etc. can be used. Examples of thermosetting composite materials include combinations of epoxy resins, vinyl ester resins, phenol resins, unsaturated polyester resins, and reinforcing fibers such as carbon fibers, glass fibers, and aramid fibers. When using a golf club head as a hollow body, a combination of carbon fiber and epoxy resin or vinyl ester resin is preferable from the viewpoint of weight reduction and impact resistance, and using BMO is preferable from the viewpoint of cost and operability. More preferably b0 To remove the core after molding, use water or alkaline water, preferably 3
Using hot water of 0 to 90℃ or alkaline hot water is
This is preferable in that the core is quickly disintegrated and removed.

When a core made of sand is molded, some sand adheres to the inner layer of the hollow body made of composite material after the sand is removed. It is preferable to wrap the core in various films such as the following to prevent sand from adhering to it.

〔Example〕

The present invention will be specifically explained below using Examples.

Example 1 An example in which the present invention is applied to molding a golf club head is shown.

A solid material made by kneading 97 parts by weight of Flattery silica sand and 3 parts by weight of a binder (manufactured by Hodogaya Ashland ■, Kemre 630/6000), which is 8 mm smaller from the face side than the golf club head and 25~3+w smaller on the other surfaces. I made this and used it as a core.

As shown in FIG. 1, the core was placed in a mold, epoxy resin and BMO made from carbon fibers having an average length of 12 m were placed around its outer periphery, and heat and pressure molding was performed.

After demolding, the 0FRP layer at the bottom of the head was hollowed out by approximately 2 cfn x 3 m, and immersed in 50 L of INNaOH aqueous solution to break up the sand in the core and extracted to obtain a hollow OIFRP golf club head.

The sand used as the core has excellent heat resistance and pressure resistance, so sufficient molding pressure could be applied, and there were no filling defects or internal cracks.

When the obtained head was used as a golf club, both the flight distance and directionality of the ball were good, and no troubles occurred.

For comparison, an attempt was made to make a hollow molded article in the same manner as in Example 1 without the above-mentioned core, but distortion occurred during heating and pressure molding, making it impossible to make a golf club head.

〔Effect of the invention〕

According to the present invention, dimensional accuracy is improved, hollow bodies with complex shapes can be molded, and high pressure molding is possible, and product performance is greatly improved! -1 It has excellent suitability especially for molding large heads of golf clubs and baseball bats.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing a molding procedure suitable for carrying out the present invention.

Claims (1)

[Claims] When molding a hollow body using a thermosetting composite material, the periphery of a core made of solid sand hardened with a binder is coated with the thermosetting composite material, and after heat curing molding, the core is A method for forming a hollow body, characterized in that removal is performed with water or alkaline water.