JP2000086784A - Prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prepreg suitable for an internal pressure molding, having a good resin flow-suppressing function even under a high temperature and high pressure in spite of a high resin content rate (33-45 wt.%), and equipped with a rapid curing property at the same time. SOLUTION: This prepreg has 0.1-1.5 min gel time at 150 deg.C, 35-45 wt.% resin content rate and a resin flow index shown by the equation, resin flow index = resin flow (wt.%)/resin content (wt.%) (where, 0.03 <= resin flow index <=0.51). As a matrix resin which can be used as the prepreg showing the above physical properties, a resin composition consisting of (A) 100 pts.wt. epoxy resin, (B) 2-10 pt.wt. amine-based latent curing agent, (C) 2-5 pt.wt. alkyl urea type curing accelerator, and (D) 5-15 pt.wt. thixotropic agent, can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg for producing a fiber reinforced molding (FRP) using a fiber reinforcing material such as carbon fiber.

More specifically, in a prepreg for pressure molding, which has an advantage that a molded article having a complicated shape can be molded in a short time, particularly in internal pressure molding, the resin flow property at the time of molding (in spite of a high resin content). (Prevents resin outflow).

[0003]

2. Description of the Related Art A prepreg comprising a fiber reinforced material such as carbon fiber and a matrix resin is used for sports and leisure applications such as a golf shaft, a fishing rod, a frame of a tennis racket, a drive shaft of an automobile, a steering wheel, a vehicle body, and a structural member of an aircraft. It is widely used by transportation organizations such as.

In such applications, as a method of forming a pipe-shaped molded product such as a golf shaft and a fishing rod, a prepreg is laid up with a predetermined orientation on a mandrel, a shrinkable tape is wound around the outer periphery, and after heating and curing, A method (tape wrapping method) of removing a tape and pulling out a mandrel to obtain a molded product is common.

[0005] As a problem at the time of molding a pipe-shaped molded product, there is mainly a problem of a resin flow such as a resin flow at the time of curing and a protrusion. The resin flow leads to irregularities in the product weight due to turbulence of the fiber reinforced material and extrusion of the resin in the molding process, leading to the generation of surface voids in the molded product,
This has been a problem in the performance of fiber reinforced materials.

Various methods for preventing such a resin flow have been studied so far, and are roughly divided into two methods.

One method is to reduce the resin content ratio (RC) of the prepreg itself (JP-A-1-279).
No. 932, JP-A-9-220969). This method
The above-mentioned publication describes that a pipe-shaped molded product is molded using a prepreg having an RC of 30% or less, and a good molded product is obtained without disturbance of a fiber reinforcing material. However, if the RC is lowered to suppress the resin flow, a resin defect is likely to occur on the surface of the molded product.

As another method, a method of improving the resin flow property by blending polyester urethane with an epoxy resin (Japanese Patent Laid-Open No. 5-117423), and a method of improving the resin flow property by blending an organic thixotropy-imparting material are disclosed. (Japanese Unexamined Patent Publication No. Hei 7-76647), a method of improving resin flowability by blending a fibrous inorganic filler (Japanese Unexamined Patent Publication No. Hei 8-41).
174, JP-A-8-20706), a method of improving resin flowability by blending a phenoxy resin (JP-A-7-118414), and improving resin flowability by blending intramolecular epoxidized polybutadiene (Japanese Unexamined Patent Publication No. 4-153252), a method of improving the resin flowability by blending a thermoplastic polyester resin (Japanese Unexamined Patent Publication No.
No. 41645) is known.

When a pipe-like molded product is molded by tape wrapping using these conventional prepregs, there is no excessive resin flow during molding, and a good molded product can be obtained.

However, the prepregs shown therein are
Although effective for long-time molding methods such as the tape wrapping method, the internal pressure molding method, which involves molding at higher temperatures, high pressures, and in a short time, suffers from a sharp decrease in viscosity due to the rapid temperature and pressure rise. It has a problem that it cannot withstand and still generates a resin flow.

The internal pressure molding method is a method in which a prepreg, which is a molding material, is laid up on an inflatable mandrel, the mandrel is expanded after being placed in a mold, and the molding material is pressed against the inner surface of the mold and cured by heating. This has the advantage that a molded article having a complicated shape can be molded in a short time.

[0012] A hollow body is used as an inflatable mandrel in the internal pressure molding method, and a fluid is injected to expand the mandrel;
Alternatively, there is a method of expanding the mandrel by utilizing the thermal expansion of the mandrel itself.

In the internal pressure molding method, at the time of molding, the lay-up layer is pressed against the inner surface of the mold at a high pressure (about 10 kg / cm ² ). As a result, the resin easily flows on the pressed surface. With the recent trend of setting RC low and increasing the fiber content (Vf) of the molded product, a portion of the matrix resin on the surface is likely to be deficient, voids are generated in the molded product, and the physical properties of the molded product are deteriorated. The problem of becoming conspicuous appears.

On the other hand, if the RC of the prepreg is increased, it is considered that even if a resin flow occurs on the pressing surface, a defect of the matrix resin on the surface is not generated, and the problem that voids are generated is solved. But actually, RC
When molding is performed using a prepreg having a high resin flow, the resin flow increases, and as a result, even though the Vf of the entire molded product is low,
The tendency to increase Vf near the surface of the molded product does not change and still causes voids.

A molded product having surface voids must be subjected to a step of performing a finishing treatment such as filling with putty or the like to the surface polishing step, which causes an increase in cost.

Therefore, even in the internal pressure molding characterized by high temperature, high pressure and short time molding, the resin flow suppressing ability is high despite the high RC, in spite of the demand for good finish of the molded product. A need has arisen to develop prepregs that combine fast curing.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to provide a prepreg having a good finished product.

In particular, it has good resin flow suppressing ability even under high temperature and high pressure despite high RC, suitable for internal pressure molding.
Another object of the present invention is to provide a prepreg having both quick-curing properties.

[0019]

According to the present invention, there is provided a prepreg comprising a fiber reinforced material impregnated with a matrix resin and having a gel time at 150 ° C. of 0.1 to 1.5. The resin flow index at a temperature of 150 ° C. × a pressure of 10 kg / cm ² is represented by the following equation, and the resin content is 35% by weight to 45% by weight.

Resin flow index = resin flow (% by weight) /
Resin content (% by weight) 0.03 ≦ resin flow index ≦ 0.51 In the present invention, the resin flow index refers to the difference between the resin content and the resin flow in a prepreg obtained by impregnating a matrix resin into a fiber reinforced material. Since there is a positive correlation between them, the relationship is defined as a resin flow index, which is defined as a value that indicates the ability to suppress resin flow. By adjusting the resin flow index, the resin flow suppressing ability can be adjusted.

If the resin flow index is less than 0.03,
Voids are generated on the shaft surface due to insufficient resin flow during FRP molding.

When the resin flow index is more than 0.51, the resin flow is large, so that the resin flows at the time of FRP molding, and voids are generated on the surface of the molded product.

The matrix resin for constituting the prepreg of the present invention having such physical properties is as follows (A):
It is desirable to contain the components (B), (C) and (D), and to make the mixing ratios of the respective components below. : (A) 100 parts by weight of epoxy resin (B) 2 to 10 parts by weight of amine latent curing agent (C) 2 to 5 parts by weight of alkyl urea type curing accelerator (D) 5 to 15 parts by weight of thixotropic agent The fiber reinforcing material for constituting the prepreg of the present invention having the following can be selected from one or a combination of two or more of carbon fiber, boron fiber, silicone carbide fiber, glass fiber, tyrano fiber and aramid fiber. .

The prepreg of the present invention has a resin content (RC) of 35% by weight to 45% by weight and belongs to a high RC prepreg. When this prepreg is applied to pressure molding, particularly to internal pressure molding, it is molded. It is unlikely to cause a defective portion of the matrix resin on the surface of the object, and is excellent in quick-curing property and resin flow suppressing effect.

In the present invention, fast-curing means one having a gel time at 150 ° C. of 0.1 to 1.5 minutes.

In the present invention, the resin flow and the gel time are measured as follows. Measurement of Resin Flow According to the method described in JIS K-7071-1988 “Test method for prepreg composed of carbon fiber and epoxy resin”, but applied to prepreg for internal pressure molding,
0.99 ° C. press sets after 10 kg / cm ² pressure × 10
The evaluation was performed under the condition of hold for one minute. Measurement of Gel Time The gel time was measured at 150 ° C. using a JSR type curast meter (manufactured by Imanaka Machine Industry Co., Ltd.).

The fiber reinforced material that can be used in the present invention includes carbon fiber, glass fiber, aramid fiber, and Tyranno fiber used for the fiber reinforced resin composite material.
In particular, carbon fibers are suitable for the purpose of obtaining a composite material having high strength and high elastic modulus. Among the carbon fibers, polyacrylonitrile-based high-strength carbon fibers are suitable from the viewpoint of handleability and mechanical properties of the obtained composite material.

The form of the fiber reinforced material is usually used for a prepreg, and a unidirectionally oriented fiber material, a woven fabric or the like can be applied.

The matrix resin used in the present invention is an epoxy resin composition, and the following components are preferably used.

Component (A) The epoxy resin is not particularly limited, and bisphenol A type epoxy resin, other glycidyl ether type epoxy resin, for example, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and phenol Novolak epoxy resin, cresol novolak epoxy resin, glycidylamine epoxy resin, naphthalene epoxy resin, brominated bisphenol A epoxy resin, glycidyl ester epoxy resin, cycloaliphatic epoxy resin, heterocyclic epoxy resin, etc. No. Also, if desired, a urethane-modified epoxy resin,
A rubber-modified epoxy resin, an alkyd-modified epoxy resin, or the like may be used. Among them, they can be appropriately mixed and used according to necessary characteristics such as handleability, economy, and physical properties of the composite material.

Component (B) As the curing agent component of the epoxy resin, one that functions as a curing agent at 50 ° C. or higher from the viewpoint of storage stability of the prepreg is preferable, and an amine-based latent curing agent is mentioned. For example,
As an amine-based latent curing agent, dicyandiamide, methylguanidine, ethylguanidine, propylguanidine, butylguanidine, dimethylguanidine, trimethylguanidine, phenylguanidine, diphenylguanidine, triylguanidine, 2,3-guanylurea,
Guanidine-based compounds such as benzoyldicyandiamide, 2,6-xylenylbiguanide and phenylbiguanide are exemplified.

Other examples of the amine-based latent curing agent include adipic dihydrazide, sebacic dihydrazide, succinic dihydrazide, glutanic dihydrazide,
Oxalic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, p-
Examples thereof include polyhydric carboxylic acid polyhydrazide compounds such as oxybenzoic acid hydrazide, salicylic acid hydrazide, maleic acid dihydrazide, dimer acid dihydrazide, and azelaic acid dihydrazide.

These amine-based latent curing agents can be used alone or in combination of two or more depending on the required characteristics. In particular, dicyandiamide and adipic dihydrazide are preferable in terms of storage stability, economy, and physical properties of the composite material.

The amount of these amine-based latent curing agents is appropriately adjusted depending on the required properties such as the physical properties and storage stability of the cured product.
10 parts by weight are used. When the amount is less than 2 parts by weight, curing is insufficient, and when the amount is more than 10 parts by weight, physical properties of a cured product are liable to be deteriorated.

(C) Component The curing accelerator component includes an alkyl urea type curing accelerator. For example, 3- (3,4-dichlorophenyl) -1,1-N-dimethylurea, 3-phenyl-
1,1-dimethylurea, 3- (4-chlorophenyl)-
1,1-dimethylurea, 3- (4-methoxyphenyl)
-1,1-dimethylurea, 1,1′-4 (methyl-m-
(Phenylene) bis (3,3′dimethylurea), trimethylurea and the like. In particular, 1,1′-4 (methyl-m-phenylene) bis (3,3′dimethylurea) is used because it is excellent in storage stability at ordinary temperature and has an effect on resin flow suppression due to excellent fast curing property. Is preferred.
The addition amount of the curing accelerator is 2 to 5 parts by weight based on 100 parts by weight of the component (A). When the amount is less than 2 parts by weight, the quick-curing property is insufficient, and the resin flow suppressing effect cannot be obtained. Conversely, if the amount is more than 5 parts by weight, the resin flow suppressing ability is too high, which not only causes voids in the molded product, but also lowers the storage stability of the prepreg, which is not preferable.

Component (D) As the thixotropic component, an inorganic filler is used in consideration of resin flow suppression, impregnation into fiber reinforcement or workability of prepreg, moldability, economy, and storage stability. Is preferred. As the inorganic filler, for example, aluminum borate,
Examples include calcium carbonate, silicon carbonate, silicon nitride, potassium titanate, basic magnesium sulfate, zinc oxide, graphite, calcium sulfate, magnesium borate, magnesium oxide, magnesium silicate, and aluminum silicate. One or two or more of these inorganic fillers are appropriately used. Among these, in particular, from the viewpoint of the resin flow suppressing effect, the apparent density is 100 to 130 g /
It is preferred to use a mixture of 1 magnesium silicate and aluminum silicate.

The mixing amount of the thixotropic agent is 5 to 15 parts by weight based on 100 parts by weight of the component (A). If the amount is less than 5 parts by weight, there is no sufficient flow suppressing effect at the time of molding, and if it exceeds 15 parts by weight, not only the resin flow suppressing effect is too high, but also the impregnating property to the fiber in the prepreg forming step tends to decrease, which is not preferable.

To manufacture a prepreg using these fiber reinforced materials and matrix resin, a general prepreg manufacturing method can be applied, and the fiber reinforced material is impregnated directly by, for example, a hot melt method or by a film method. May be used.

[0039]

The present invention will be described in more detail with reference to the following examples.

Example 1 100 parts by weight of an epoxy resin (phenol novolak type epoxy resin: trade name: E)
p. 154, 70 parts by weight manufactured by Yuka Shell Epoxy Co., Ltd.
And bisphenol A type epoxy resin: Trade name: Ep.
1002, 30 parts by weight of Yuka Shell Epoxy Co., Ltd.) as a curing agent, dicyandiamide (trade name: DIC)
3 parts by weight of Y7, Yuka Shell Epoxy Co., Ltd., and 1,1′-4 (methyl-m-phenylene) as a curing accelerator
Bis (3,3'dimethylurea) (trade name Omicure 2
4, ACI Corporation) 3 parts by weight, thixotropic agent (trade name: DT-
5039, manufactured by Asahi Chiba Co., Ltd.) was used to prepare an epoxy resin composition comprising 10 parts by weight using a roll mill.

This resin composition and high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Example 1. The resin content of this prepreg is 40% by weight,
The gel time at 150 ° C. was 0.8 minutes.

The resin flow of this prepreg was 10.9% by weight, and the flow index was 0.27. A golf shaft was formed at a molding temperature of 15 using the obtained prepreg.
0 ° C., molding time 10 min, molding pressure 10 kgf / cm ²
When molded by the internal pressure molding method under the conditions, the resin flow at the time of molding the shaft was 3.4% by weight, and the number of voids on the shaft surface was very small at 0.10 / cm ² , showing good moldability. Was.

The composition of the matrix resin used, the properties of the prepreg, and the moldability when using the prepreg are summarized in Table 1 below.

Example 2 The resin composition and carbon fiber shown in Example 1 were used, and the carbon fiber basis weight was 115 g /
A prepreg having m ² and a resin content of 42% by weight was prepared. The gel time at 150 ° C. of this prepreg was 0.9 minutes.

The resin flow of this prepreg was 13.7.
% By weight and the flow index was 0.33. Also,
As a result of molding a golf shaft by an internal pressure molding method using the obtained prepreg, an appropriate resin flow at the time of molding the shaft was found to be 4.0% by weight, and voids on the shaft surface were also 0.15 / cm ^2. , And showed good moldability.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded articles using the prepreg are summarized in Table 1 below.

Example 3 The resin composition and carbon fiber shown in Example 1 were used, and the basis weight of carbon fiber was 115 g /
A prepreg of Example 3 having m ² and a resin content of 38% by weight was produced. The gel time at 150 ° C. of this prepreg was 0.6 minutes.

The resin flow of this prepreg was 8.5% by weight, and the flow index was 0.22. In addition, as a result of molding the golf shaft by the internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was 3.0% by weight, which was an appropriate flow, and the voids on the shaft surface were 0.13 / void. cm ² , indicating a good moldability.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded article using the prepreg are summarized in Table 1 below.

Example 4 An epoxy resin composition comprising 3 parts by weight of a curing agent component, 3 parts by weight of a curing accelerator component and 5 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Example 4 having a resin content of 40% by weight. The gel time at 150 ° C. of this prepreg was 1.0 minute.

The resin flow of this prepreg was 16.1% by weight, and the flow index was 0.40. When a golf shaft was molded by an internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was slightly larger at 4.4% by weight, but the void on the shaft surface was 0.19%. Pieces / cm ² , indicating good moldability.

The composition of the used matrix resin, the properties of the prepreg, and the physical properties of the molded article using the prepreg are shown in Table 1 below.

Example 5 An epoxy resin composition comprising 3 parts by weight of a curing agent component, 3 parts by weight of a curing accelerator component, and 8 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and high-strength carbon fiber (trade name: UT500 strand tensile strength 490, manufactured by Toho Rayon Co., Ltd.)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Example 5 having a resin content of 40% by weight. The gel time at 150 ° C. of this prepreg was 0.9 minutes.

The resin flow of this prepreg was 13.2% by weight, and the flow index was 0.33. Further, when a golf shaft is molded by an internal pressure molding method using the obtained prepreg, a resin flow at the time of molding the shaft is 2.0% by weight, which is an appropriate flow, and a void on the shaft surface is 0.15%. Pcs / cm ^2, which was very small, indicating good moldability.

The composition of the used matrix resin, the properties of the prepreg, and the physical properties of the molded article using the prepreg are shown in Table 1 below.

Example 6 An epoxy resin composition comprising 3 parts by weight of a curing agent component, 3 parts by weight of a curing accelerator component and 12 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Example 6 having a resin content of 40% by weight. The gel time at 150 ° C. of this prepreg was 0.7 minutes.

The resin flow of this prepreg was 9.6% by weight, and the flow index was 0.24. Also, when a golf shaft was molded by an internal pressure molding method using the obtained prepreg, a resin flow at the time of molding the shaft was 3.2% by weight, and an appropriate flow was recognized. Pcs / cm ^2, which was very small, indicating good moldability.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded article using the prepreg are summarized in Table 1 below.

Example 7 An epoxy resin composition comprising 3 parts by weight of a curing agent component, 3 parts by weight of a curing accelerator component and 15 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Example 7 having a resin content of 40% by weight. The gel time at 150 ° C. of this prepreg was 0.6 minutes.

The resin flow of this prepreg was 7.9% by weight, and the flow index was 0.20. When a golf shaft was molded by an internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was slightly lower at 2.8% by weight, but the void on the shaft surface was 0.16% by weight. Pieces / cm ² , indicating good moldability.

The composition of the used matrix resin, the properties of the prepreg, and the physical properties of the molded article using the prepreg are shown in Table 1 below.

Example 8 An epoxy resin composition comprising 2 parts by weight of a curing agent component, 2 parts by weight of a curing accelerator component, and 5 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Example 8 having a resin content of 40% by weight. The gel time at 150 ° C. of this prepreg was 1.3 minutes.

The resin flow of this prepreg was 17.0% by weight, and the flow index was 0.43. When a golf shaft was molded by an internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was slightly higher at 4.6% by weight, but the void on the shaft surface was 0.21%. Pieces / cm ² , indicating good moldability.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded article using the prepreg are summarized in Table 1 below.

Example 9 An epoxy resin composition comprising 2 parts by weight of a curing agent component, 2 parts by weight of a curing accelerator component, and 5 parts by weight of a thixotropic agent component was used in a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and high-strength carbon fiber (UT500 strand tensile strength 490, manufactured by Toho Rayon Co., Ltd.)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Example 9 having a resin content of 42% by weight. The gel time at 150 ° C. of this prepreg was 1.4 minutes.

The resin flow of this prepreg was 19.3% by weight, and the flow index was 0.46. Also, when a golf shaft was molded by an internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was slightly higher at 4.8% by weight, but the void on the shaft surface was 0.23% by weight. Pieces / cm ² , indicating good moldability.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded articles using the prepreg are shown in Table 1 below.

Example 10 10 parts by weight of a curing agent component and 5 parts by weight of a curing accelerator component were added to 100 parts by weight of an epoxy resin.
An epoxy resin composition comprising 15 parts by weight of a thixotropic agent component was prepared using a roll mill.

This resin composition and high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Example 10 having a resin content of 40% by weight. The gel time at 150 ° C. of this prepreg was 0.5 minutes.

The resin flow of this prepreg was 7.1% by weight, and the flow index was 0.18. When a golf shaft was molded by an internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was slightly lower at 2.8% by weight, but the void on the shaft surface was 0.16% by weight. Pieces / cm ² , indicating good moldability.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded article using the prepreg are shown in Table 1 below.

Example 11 10 parts by weight of a curing agent component and 5 parts by weight of a curing accelerator component were added to 100 parts by weight of an epoxy resin.
An epoxy resin composition comprising 15 parts by weight of a thixotropic agent component was prepared using a roll mill.

This resin composition and high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Example 11 having a resin content of 38% by weight. The gel time at 150 ° C. of this prepreg was 0.4 minutes.

The resin flow of this prepreg was 4.9% by weight, and the flow index was 0.13. When a golf shaft was molded by the internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was slightly lower at 2.4% by weight, but the void on the shaft surface was 0.21%. Pieces / cm ² , indicating good moldability.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded article using the prepreg are shown in Table 1 below.

Comparative Example 1 An epoxy resin composition comprising 3 parts by weight of a curing agent component, 3 parts by weight of a curing accelerator component, and 10 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

The resin composition and high-strength carbon fiber (trade name: UT500 strand tensile strength 490, manufactured by Toho Rayon Co., Ltd.)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Comparative Example 1 having a resin content of 32% by weight. 1 of this prepreg
The gel time at 50 ° C. was 0.4 minutes.

The resin flow of this prepreg was 0.7% by weight, and the flow index was as low as 0.02. Also, when a golf shaft is molded by an internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft is as small as 1.6% by weight, and the resin flow suppressing ability is high.
The voids on the shaft surface were as large as 0.30 / cm ^2, and no good molded product was obtained.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded article using the prepreg are shown in Table 2 below.

Comparative Example 2 An epoxy resin composition comprising 3 parts by weight of a curing agent component, 3 parts by weight of a curing accelerator component, and 10 parts by weight of a thixotropic agent component was used in a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Comparative Example 2 having a resin content of 49% by weight. 1 of this prepreg
The gel time at 50 ° C. was 1.2 minutes.

The resin flow of this prepreg was 26.0% by weight, and the flow index was as high as 0.53. Also,
When a golf shaft is molded by the internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft is as large as 5.2% by weight, and the resin flow suppressing ability is low.
The number of voids on the shaft surface was as large as 0.32 / cm ^2, and no good molded product was obtained.

The composition of the used matrix resin, the properties of the prepreg, and the physical properties of the molded article using the prepreg are shown in Table 2 below.

Comparative Example 3 An epoxy resin composition comprising 10 parts by weight of a curing agent component, 8 parts by weight of a curing accelerator component and 18 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and a high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Comparative Example 3 having a resin content of 40% by weight. 1 of this prepreg
The gel time at 50 ° C. was 0.08 minutes.

The prepreg had a resin flow of 0.6% by weight and a low flow index of 0.02. When a golf shaft was molded by the internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was as small as 1.0% by weight. Since the resin flow suppressing ability was high and the resin was cured in a shorter time, voids on the shaft surface were as large as 0.38 / cm ^2, and a good molded product was not obtained.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded article using the prepreg are shown in Table 2 below.

Comparative Example 4 An epoxy resin composition comprising 2 parts by weight of a curing agent component, 1 part by weight of a curing accelerator component, and 3 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

The resin composition and a high-strength carbon fiber (UT500 strand tensile strength 490, manufactured by Toho Rayon Co., Ltd.)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Comparative Example 4 having a resin content of 40% by weight. 1 of this prepreg
The gel time at 50 ° C. was 1.8 minutes.

The resin flow of this prepreg was 28.0% by weight, and the flow index was as high as 0.70. Also,
When a golf shaft was molded by the internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was as high as 7.0% by weight. Since the resin flow suppressing ability was low and the curing had a long time, the number of voids on the shaft surface was as large as 0.40 / cm ^2, and a good molded product could not be obtained.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded articles using the prepreg are summarized in Table 2 below.

Comparative Example 5 An epoxy resin composition comprising 10 parts by weight of a curing agent component, 8 parts by weight of a curing accelerator component and 5 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and high-strength carbon fiber (trade name: UT500 strand tensile strength 490, manufactured by Toho Rayon Co., Ltd.)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Comparative Example 5 having a resin content of 32% by weight. The gel time at 150 ° C. of this prepreg was 0.05 minutes.

The resin flow of this prepreg was 1.2 weight
% And the flow index was 0.04. Also obtained
Golf shaft using internal prepreg
More molding, the resin flow during shaft molding is
1.8% by weight, but the prepreg hardened in a shorter time.
0.28 voids / cm on the shaft surface
^TwoAnd a good molded product was not obtained.

The composition of the used matrix resin, the properties of the prepreg, and the physical properties of the molded article using the prepreg are shown in Table 2 below.

Comparative Example 6 An epoxy resin composition comprising 2 parts by weight of a curing agent component, 1 part by weight of a curing accelerator component, and 15 parts by weight of a thixotropic agent component was used on a roll mill with respect to 100 parts by weight of an epoxy resin. Prepared.

This resin composition and a high-strength carbon fiber (manufactured by Toho Rayon Co., Ltd., UT500 strand tensile strength 490)
kgf / mm ² , tensile modulus 24.5 ton / mm ² )
And one-way prepreg (carbon fiber weight is 115 g / m
² ) was produced by a hot melt method to obtain a prepreg of Comparative Example 6 having a resin content of 49% by weight. 1 of this prepreg
The gel time at 50 ° C. was 2.1 minutes.

The resin flow of this prepreg was 22.7% by weight, and the flow index was 0.46. Also, when a golf shaft was molded by the internal pressure molding method using the obtained prepreg, the resin flow at the time of molding the shaft was as high as 5.0% by weight. Since it took a long time to cure the prepreg, sufficient flow suppressing ability was not obtained, and the voids on the shaft surface were as large as 0.30 / cm ^2, and a good molded product was not obtained.

The composition of the matrix resin used, the properties of the prepreg, and the physical properties of the molded articles using the prepreg are shown in Table 2 below.

In the judgment columns of Tables 1 and 2 below, ◎,
○, △, and × are each determined from the number of voids generated on the shaft surface after molding, and the definitions are as follows. A: Very good with a shaft surface void of 0.15 / cm ² or less. ：: shaft surface voids 0.16 to 0.25 / cm ²
And good ones. Δ: shaft surface voids 0.26 to 0.35 / cm ²
With trouble in molding condition. ×: Shaft surface voids of 0.36 / cm ² or more and poor molded state.

[0107]

[Table 1]

[0108]

[Table 2]

[0109]

The prepreg of the present invention has a resin content of 3
Despite its high content of 5% to 45% by weight, it has good resin flow suppression ability even under high temperature and high pressure, and has a gel time at 150 ° C. of 0.1 to 1.5 minutes and has fast curing properties. By doing so, the finished state of the surface of the molded article after molding is good. In particular, the prepreg of the present invention is suitable as a material for internal pressure molding.

Continued on the front page (72) Inventor Masato Ando 234, Kamitsukari, Nagaizumi-cho, Sunto-gun, Shizuoka Prefecture Toho Rayon Co., Ltd. F-term (reference) 4F072 AA06 AB06 AB08 AB09 AB10 AB11 AD23 AE02 AE04 AE15 AF28 AG03

Claims (4)

[Claims] 1. A prepreg comprising a fiber reinforced material impregnated with a matrix resin, having a gel time at 150 ° C. of 0.1 to 1.5 minutes, a temperature of 150 ° C. and a pressure of 10 kg / cm.
^2. A prepreg, wherein the resin flow index of ² has a relationship represented by the following formula, and the resin content is 35% by weight to 45% by weight. Resin flow index = resin flow (% by weight) / resin content (% by weight) 0.03 ≦ resin flow index ≦ 0.51 2. The matrix resin according to the following (A),
2. The prepreg according to claim 1, comprising components (B), (C) and (D), and the mixing ratio of each is as follows. (A) 100 parts by weight of epoxy resin (B) 2 to 10 parts by weight of amine-based latent curing agent (C) 2 to 5 parts by weight of alkyl urea type curing accelerator (D) 5 to 15 parts by weight of thixotropic agent 3. The prepreg according to claim 1, wherein the fiber reinforcement comprises one or a combination of two or more of carbon fiber, boron fiber, silicone carbide fiber, glass fiber, Tyranno fiber and aramid fiber. 4. The prepreg according to claim 1, wherein the fiber reinforcement is carbon fiber.