JP2001139662A - Epoxy resin composition, prepreg and golf shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition which is not accompanied by a viscosity increase having a bad effect on the ability to pass the processes, has a good adhesion to reinforced fibers and shows an excellent impact resistance when applied to a FRP, a prepreg and a golf shaft which does not break in an air cannon practical hitting test using this prepreg. SOLUTION: An epoxy resin composition essentially comprises (A) an epoxy resin having a structure of formula (1) and (B) a rubber-modified epoxy resin or (B) a mixture of a reactive rubber and an epoxy resin. The composition has a viscosity at 60 deg.C of from 100 to 5,000 P and yields a cured product having a GIc of >=1 kJ/m2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition and a prepreg excellent in impact resistance, and more particularly to a golf shaft which does not break in an air cannon actual hit test.

[0002]

2. Description of the Related Art Epoxy resin compositions have excellent adhesiveness,
After curing, the resin has excellent mechanical and electrical properties, and is therefore applied to a wide range of fields such as sealing materials for electronic materials, paints / paving materials, and adhesives. Further, the epoxy resin composition is also used as a matrix resin of a fiber reinforced plastic (hereinafter, referred to as FRP). Utilizing the advantages of strength and high elastic modulus, it is widely used for structural materials such as aircraft, ships, and automobiles, industrial uses such as rolls and tanks, and even sports uses such as golf shafts, heads, and tennis rackets. .

[0003] Such an FRP is formed using an intermediate material (hereinafter, referred to as a prepreg) in which a reinforcing fiber such as CF is impregnated with an epoxy resin composition as a matrix resin in advance. A matrix resin suitable for this prepreg has excellent mechanical properties after molding, good adhesion to reinforcing fibers, moderate tackiness at working temperature (hereinafter referred to as tack), and excellent workability. Is required.

[0004] The above-mentioned various properties greatly differ depending on the composition of the epoxy resin composition. Currently, the most common compositions are mainly composed of a bisphenol A type epoxy resin and a phenol novolak type epoxy resin, and are mixed with a curing agent. Epoxy resin composition.

[0005] However, in recent years, as the applications of FRPs have been increasingly expanded and diversified, high mechanical properties which cannot be achieved by conventional epoxy resin compositions have been required. For example, there is a demand for improvement in mechanical properties in a direction perpendicular to the fiber direction of the FRP, and prevention of damage such as peeling between layers of the prepreg when an impact force is applied to the FRP.

Various epoxy resin compositions have been proposed to satisfy the above requirements. JP-A-63-37135-7
In Japanese Patent Application Laid-Open Publication No. H11-107, attempts have been made to improve the toughness of the matrix resin by adding a thermoplastic resin such as polyvinyl formal to the epoxy resin composition after dissolving it, and to improve the above properties.

[0007]

However, the viscosity of the epoxy resin composition described in the above-mentioned publication increases significantly due to the addition of a thermoplastic resin, and the epoxy resin composition required for the production of prepregs has several tens of epoxy resin compositions on release paper. It was difficult to apply a coating having a thickness of μm, and there was a problem in the processability of the prepreg.

[0008] In view of the above problems, the present inventors considered that the mechanical properties of the FRP in the direction perpendicular to the fiber direction of the FRP were good without increasing the viscosity which adversely affects the process passability, and with good adhesion to the reinforcing fibers. The present inventors have intensively studied an epoxy resin composition and a prepreg exhibiting excellent impact resistance while achieving excellent impact resistance, and arrived at the present invention.

[0009]

That is, the gist of the present invention is that the following (A) and (B) or (A) and (B) are essential components and the viscosity at 60 ° C. is 100 to 500.
The epoxy resin composition has 0 poise, and the cured product has a G _Ic of 1 KJ / m ² or more. Further, the gist of the present invention is a golf shaft which is not broken by the actual hit test of 500 air cannons at a distance of 2 m, an initial speed of 54 m / sec, and 500 shots.

(A) Epoxy resin having a structure represented by the following formula (1) (B) Rubber-modified epoxy resin (B) Mixture of reactive rubber and epoxy resin

[0011]

Embedded image

Wherein R is independently a hydrogen atom or a methyl group, X _{1 to} X ₄ are each independently a halogen atom, a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms, and R _{1 to} R ₄ are each independently A hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
A is the following formula (2) or (3).

[0013]

Embedded image

However, R ′ ₁ to R ′ ₄ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0015]

Embedded image

Wherein R ″ ₁ to R ″ ₈ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, B is a single bond,
_{CH 2 -, - C (CH} 3) 2 -, - S -, - SO -, -
SO ₂ — or —O—.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION (A) Epoxy resin having a structure represented by formula (1) In the epoxy resin composition of the present invention, an epoxy resin having an epoxy resin having a structure represented by formula (1) is used. Use is necessary to achieve the purpose. The number of epoxy groups per molecule contained in this epoxy resin is preferably 1.2 to 5 on average, and more preferably 1.2 to 3 on average.

[0018]

Embedded image

Wherein R is independently a hydrogen atom or a methyl group, X _{1 to} X ₄ are each independently a halogen atom, a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms, and R _{1 to} R ₄ are each independently A hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
A is the following formula (2) or (3).

[0020]

Embedded image

However, R ′ ₁ to R ′ ₄ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0022]

Embedded image

Wherein R ″ ₁ to R ″ ₈ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, B is a single bond,
_{CH 2 -, - C (CH} 3) 2 -, - S -, - SO -, -
SO ₂ — or —O—.

As the epoxy resin having the structure represented by the formula (1), XAC4151, XAC4 manufactured by Asahi Ciba Co., Ltd.
152 can be exemplified, but is not limited to this.

(B) Rubber-Modified Epoxy Resin In the epoxy resin composition of the present invention, it is necessary to incorporate a rubber-modified epoxy resin.

[0026] In the present invention, the rubber-modified epoxy resin is
A rubber component having a terminal group capable of reacting with an epoxy resin, such as a butadiene / acrylonitrile polymer, a butadiene rubber, an acrylic rubber, or a styrene-butadiene elastomer, is dispersed and reacted in an epoxy resin. It is important that it is added to the epoxy resin via a group.

The modification of the epoxy resin with the rubber component is as follows:
It can be easily performed by dispersing a rubber component in an epoxy resin, heating to 100 to 180 ° C., and adding a catalyst as necessary.

Examples of commercially available epoxy resins modified with a rubber component include Epicron TSR960, TSR930, and TSR60 manufactured by Dainippon Ink and Chemicals, Inc.
1. EPI manufactured by AC I Japan Limited
-REZ58005, EPI-REZ58006, Yuko Shell Epoxy Co., Ltd. Epicoat YL6347,
Epicoat YL6308, NPA BPA
328, BPA601, BPA604, SR-35 manufactured by Mitsui Petrochemical Co., Ltd., and the like.

In the present invention, as the epoxy resin to be modified with rubber, bisphenol A type epoxy resin and bisphenol F type epoxy resin which are liquid at room temperature are preferable from the viewpoint of handleability, but are not particularly limited. That is, in addition to bisphenol A type epoxy resin and bisphenol F type epoxy resin, compounds obtained by diglycidylation of dihydric phenols such as bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol AD, tetramethylbisphenol S, and dihydroxynaphthalene. 1,1,1-tris (4-hydroxyphenyl) methane, 1,1,1-tris (4-hydroxyphenyl) ethane, 4,4 '-(1- (4- (1- (4-hydroxyphenyl) ) -1-Methylethyl (phenyl) ethylidene) tris (glycidyloxyphenyl) alkanes such as bisphenol, compounds obtained by glycidylation of aminophenols, compounds obtained by glycidylation of novolaks such as phenol novolak and cresol novolak, etc. In addition, Hiroshi Kakiuchi editing "new epoxy resin - Recent progress" (Shokodo issue, 1990) can be mentioned glycidyl compound according paragraph 46 from 21 Section.

[0030] In the present invention, the epoxy resin to be modified with rubber may be used alone, but if necessary, a mixture of two or more epoxy resins may be used.

It is preferable to mix a solid epoxy resin at room temperature with a rubber-modified epoxy resin derived from a liquid epoxy resin at room temperature because the viscosity of the epoxy resin composition can be easily adjusted.

(B) Mixture of Reactive Rubber and Epoxy Resin Previously, as the rubber-modified epoxy resin used in the present invention, a rubber-modified epoxy resin obtained by modifying an epoxy resin with a rubber component in advance was used. However, in the present invention,
When melt-mixing each component of the epoxy resin composition, the epoxy resin may be modified with a rubber component.

[0033] As a rubber component suitable for rubber-modifying the epoxy resin at the time of melt-mixing each component, CTBN1300 series manufactured by Ube Industries, Ltd. can be exemplified. When melt-mixing each component of the epoxy resin composition, 100 ~ 15
Any rubber component having a terminal group capable of reacting with the epoxy resin at a temperature of 0 ° C. is not particularly limited.

As the epoxy resin suitable for rubber-modifying the epoxy resin when the components are melt-mixed, bisphenol A type epoxy resin and bisphenol F type epoxy resin which are liquid at room temperature are preferable from the viewpoint of handleability. There is no particular limitation. That is, in addition to bisphenol A type epoxy resin and bisphenol F type epoxy resin, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol AD, tetramethylbisphenol S, dihydroxynaphthalene, etc.
Compounds obtained by diglycidylation of polyhydric phenols, 1,1,
1-tris (4-hydroxyphenyl) methane, 1,
1,1-tris (4-hydroxyphenyl) ethane,
Glycidylated tris (glycidyloxyphenyl) alkanes and aminophenols such as 4,4 '-(1- (4- (1- (4-hydroxyphenyl) -1-methylethyl (phenyl) ethylidene) bisphenol) Phenolic novolaks, cresol novolaks and other glycidylated novolaks, etc.
Edited by Hiro, "New Epoxy Resins-Recent Advances" (published by Shokodo,
(1990) 21-46.

In the present invention, the epoxy resin includes:
Although only one type of epoxy resin may be used, two or more types of epoxy resins may be mixed and used as necessary.

[0036] In the epoxy resin composition of the present invention, the constituent ratios of (A) and (B) are determined by the heat resistance after curing, the adhesion between the reinforcing fiber represented by CF and the resin, and the impact resistance of FRP. For balance, it is preferably 10/90 to 80/20 (weight ratio). Further, other epoxy resins may be added to the epoxy resin composition of the present invention without departing from the purpose of the present invention.

About the curing agent The curing agent contained in the epoxy resin composition of the present invention is:
It is preferable to use a curing agent which is usually used as a curing agent for an epoxy resin composition and is stable at room temperature and can be activated at a temperature exceeding 80 ° C. Examples of the curing agent that can be suitably used in the epoxy resin composition of the present invention include a mixture of a dicyandiamide / urea compound, an amine adduct-type imidazole-based compound, an amine-based compound, an amide-based compound, a polycarboxylic anhydride, and a phenol-based compound. Can be exemplified.

[0038] The amount of the curing agent added to the epoxy resin composition of the present invention is not particularly limited, but is preferably 1 to 20 parts by weight based on 100 parts by weight of the epoxy resin.

Regarding the viscosity of the epoxy resin composition The epoxy resin composition of the present invention needs to have a viscosity of 100 to 5000 poise at 60 ° C. in view of handleability in the prepreg production process. 6 of epoxy resin composition
If the viscosity at 0 ° C. is less than 100 poise, the tack becomes too strong when formed into a prepreg, and the handleability during molding using the prepreg tends to be significantly reduced at room temperature. Conversely, if it exceeds 5,000 poise, tackiness will not occur at room temperature, making lamination work of the prepreg difficult, and drapability will be lost, so that it will be difficult to follow the mold. More preferable upper limit and lower limit viscosities are 3500 and 300, respectively.
Poise.

[0040] G _Ic of cured product [0040] The epoxy resin composition of the present invention requires that the cured resin alone after curing at 120 ° C for 2 hours has a G _Ic of 1 KJ / m ² or more. The present inventors have proposed that a matrix resin having a G _Ic of 1 KJ / m ² or more can form a tubular FRP formed of a prepreg made of the matrix resin.
The impact resistance of the tubular FRP was remarkably improved, and this tubular FRP was processed into a golf club. Here, the air cannon actual hit test is a type of endurance test of a golf club in which a golf ball is hit at a desired initial speed from a position approximately 2 m away from the golf head and the golf ball is hit against the golf head with the grip of the golf club fixed. .

Method for Adjusting Epoxy Resin Composition The method for adjusting the epoxy resin composition of the present invention is not particularly limited, and can be carried out by a conventionally known method. However, when heating and adjusting each epoxy resin component, it is important to cool once and to add a curing agent in order to keep the potable life of the epoxy resin composition and the prepreg composed thereof sufficiently long.

[0042] The epoxy resin composition of the present invention can be impregnated into reinforcing fibers by a conventionally known method to form a prepreg. In the present invention, the type and form of the reinforcing fiber are not particularly limited, but as the reinforcing fiber, a PAN-based CF using polyacrylonitrile-based fiber as a raw material, a pitch-based CF using petroleum pitch as a raw material, a glass fiber, a silicon carbide fiber, Examples thereof include inorganic fibers such as boron fiber and stainless steel fiber, and organic reinforcing fibers typified by aramid fiber. Examples of the reinforcing form include unidirectional drawing of various reinforcing fibers, woven fabric, nonwoven fabric, and the like. And the above-mentioned embodiment using a combination of two or more types of reinforcing fibers.

In particular, the unidirectional prepreg using the epoxy resin composition of the present invention as a matrix resin and PAN-based CF as a reinforcing fiber has a 90-degree tensile and bending strength with respect to the obtained FRP reinforcing fiber. Are better. From such characteristics, a golf shaft obtained by using the above-described prepreg has an excellent property of not being broken even by an air cannon actual hitting test described below.

[0044]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. Abbreviations of compounds in the examples and comparative examples and test methods are as follows. The numerical values in the following resin composition tables indicate parts by weight. (Abbreviation of compound)

[0045]

[Table 1]

(Measurement of Viscosity of Uncured Resin) Using a dynamic viscoelasticity measuring apparatus RDA-700 manufactured by Rheometrics, two pieces of 2
An uncured epoxy resin composition was sandwiched between disk plates of 5 mmφ with a gap of 0.5 mm, the temperature was raised from room temperature at 2 ° C./min, and shear was added at 60 ° C. at 10 radians / sec.

(Preparation of prepreg) Each epoxy resin composition was
42 g / m on release paper²And apply on top of it
Fiber carbon fiber TR30S12L manufactured by Mitsubishi Rayon Co., Ltd.
125g / m ²Aligned in one direction so that
I piled up. Press with a pair of rolls to transfer the epoxy resin
Impregnated into fiber to make prepreg with resin content 25% by weight
Was.

(FRP three-point bending test) Twenty prepregs were laminated so that the fiber direction was the same, and 3
While applying a pressure of kg / cm ^2, the mixture was cured by holding at 150 ° C. for 1 hour to obtain FRP. This was cut into the shape of each test piece, and using an Orientec Co., Ltd. universal testing machine, Tensilon, at an indenter tip radius of 3.2 mm and a moving speed of the indenter of 2 mm / min, at 0 ° to the fiber direction (distance between fulcrums / A three-point bending test in the direction of thickness 40) and 90 ° (distance between supporting points / thickness 16) was performed. The shape of the test piece was 0 °: 12
0 mm length × 10 mm width × 2 mm thickness, 90 °: 60 mm length × 10 mm width × 2 mm thickness.

(Measurement Method of Strain Energy Release Coefficient G _Ic of Cured Epoxy Resin Composition)
The solution was poured between two glass plates facing each other at an interval of m and kept at 120 ° C. for 2 hours to obtain a resin plate having a thickness of 3 mm. Using this resin plate, the strain energy release coefficient _GIc was measured by a compact tension method based on ASTM-E399.

(Charpy impact test) [0050] Two prepregs were superimposed so that the directions of the reinforcing fibers were orthogonal to each other, and these were placed on a 10 mmφ stainless steel mandrel (core metal) that had been subjected to a release treatment. Is set to ± 45 ° to form a total of two FRP layers. One layer of prepreg was wound thereon such that the direction of the reinforcing fibers and the axis of the mandrel coincided with each other. From above, a polyethylene tape was wound from the end to cover the FRP layer, and kept at 140 ° C. for 2 hours in a vertical blowing furnace to obtain a tubular FRP simulating a golf shaft.

[0051] This tubular FRP was attached to a JIS type UF Charpy impact tester, and in accordance with ASTM D256,
The initial absorbed energy corresponding to the absorbed energy up to the maximum breaking load was measured.

(Air Cannon actual hitting test) 5.1
5mm, taper 9.47 / 1000, length 1500m
The superposed prepreg was wound 120 mm apart from the tip of the stainless steel mandrel that had been subjected to a mold release treatment so that the direction of the reinforcing fiber and the mandrel axis were ± 45 ° to form a total of two FRP layers. The prepreg was further wound thereon in two layers such that the direction of the reinforcing fibers and the axis of the mandrel coincided with each other. A polyethylene tape was wrapped from the end from above, covering the FRP layer, and kept at 145 ° C. for 2 hours in a vertical blowing furnace, cured, and the tape was removed.
The outer periphery was polished to obtain a golf shaft. The thickness of this shaft was 0.63 mm. A head and a grip were attached to this shaft to obtain a golf club. Air cannon actual hit test using a golf ball for this golf club (ball initial velocity 54 m / sec, distance 2 m, 500 shots)
Was performed.

(Examples 1 to 16) Epoxy resin compositions having the compositions shown in Tables 2, 3 and 4 were prepared and evaluated as described above.

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

(Comparative Examples 1 to 5) Epoxy resin compositions having the compositions shown in Table 5 were prepared, and the above evaluation was performed.

[0058]

[Table 5]

[0059]

According to the present invention, there is provided an epoxy resin composition having good adhesion to a reinforcing fiber, excellent impact resistance when FRP is obtained, without increasing the viscosity which adversely affects the processability. Prepreg can be obtained. Further, using the epoxy resin composition of the present invention, PA
One-way prepreg using N-based CF is obtained from FRP
It is excellent in tensile and bending strength in the direction of 90 degrees with respect to the reinforcing fiber. Further, the golf shaft obtained by using the above-mentioned prepreg has an excellent property that it is not broken even by the air cannon actual hitting test described below.

Continued on the front page F-term (reference) 2C002 AA05 CS03 MM02 PP01 4F072 AB08 AB09 AB10 AB11 AB28 AB29 AD29 AD30 AD34 AG03 AH21 AL05 4J002 CD13W CD20X CL063 DA017 DA087 DJ007 DK007 DL007 EJ016 EL136 EN006 EP006 ET006 EU116 FA04404 AC0 DB05 DB17 DC02 DC21 DC31 DC44 FA02 FA05 FA06 FB13 JA11 JA15 4J040 CA071 CA072 CA081 CA082 EC061 EC062 EC071 EC072 EC121 EC122 EC171 EC172 EC331 EC332 EC361 EC362 EC371 EC372 GA06 GA17 KA16 LA01 LA06 MA10 MB02 NA05

Claims (16)

[Claims] 1. An epoxy resin having a structure represented by the following formula (1) and a rubber-modified epoxy resin (B) as essential components, a viscosity of 100 to 5000 poise at 60 ° C., and a cured product of G _An epoxy resin composition having _Ic of 1 KJ / m ² or more. Embedded image However, R is each independently a hydrogen atom or a methyl group, X ₁
To X ₄ are each independently a halogen atom, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R _{1 to} R ₄ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and A is the following formula ( 2) or (3). Embedded image _However, R _'1 ~ R' ₄ are each independently a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms. Embedded image However, R ″ ₁ to R ″ ₈ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, B is a single bond, —CH
_{2 -, - C (CH 3} ) 2 -, - S -, - SO -, - SO
_2- or -O-. 2. The composition ratio of (A) and (B) is 10/90 or more.
The epoxy resin composition according to claim 1, which is 80/20 (weight ratio). 3. The epoxy resin composition according to claim 1, wherein the rubber-modified epoxy resin is a rubber-modified epoxy resin obtained by modifying an epoxy resin with an acrylic rubber. 4. The epoxy resin composition according to claim 1, wherein the rubber-modified epoxy resin is a rubber-modified epoxy resin obtained by modifying an epoxy resin with a butadiene / acrylonitrile copolymer having a carboxylic acid terminal. 5. The epoxy resin composition according to claim 1, wherein the rubber-modified epoxy resin is a rubber-modified epoxy resin obtained by modifying an epoxy resin with a butadiene rubber having a crosslinked structure. 6. The epoxy resin composition according to claim 1, wherein the rubber-modified epoxy resin is a rubber-modified epoxy resin obtained by modifying an epoxy resin with a styrene / butadiene-based elastomer having a functional group capable of reacting with the epoxy resin. 7. An essential component is (A) an epoxy resin having a structure represented by the following formula (1) and (B) a mixture of a reactive rubber and an epoxy resin, and has a viscosity of 100 to 50 at 60 ° C.
An epoxy resin composition having a viscosity of 00 poise and a cured product having a G _Ic of 1 KJ / m ² or more. Embedded image However, R is each independently a hydrogen atom or a methyl group, X ₁
To X ₄ are each independently a halogen atom, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R _{1 to} R ₄ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and A is the following formula ( 2) or (3). Embedded image _However, R _'1 ~ R' ₄ are each independently a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms. Embedded image However, R ″ ₁ to R ″ ₈ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, B is a single bond, —CH
_{2 -, - C (CH 3} ) 2 -, - S -, - SO -, - SO
_2- or -O-. 8. The composition ratio of (A) and (B) is 10/90 to
The epoxy resin composition according to claim 9, which is 80/20 (weight ratio). 9. The epoxy resin composition according to claim 7, wherein the reactive rubber is an acrylic rubber. 10. The reactive rubber is a carboxylic acid-terminated butadiene / acrylonitrile copolymer.
Or the epoxy resin composition according to 8. 11. The reactive rubber is a butadiene rubber,
The epoxy resin composition according to claim 7. 12. The epoxy resin composition according to claim 7, wherein the reactive rubber is a styrene / butadiene elastomer having a functional group capable of reacting with the epoxy resin. 13. The epoxy resin composition according to claim 1, wherein the content of the rubber component in the epoxy resin composition is 3 to 15% by weight. A prepreg comprising the epoxy resin composition according to any one of claims 1 to 13. 15. A golf shaft that is not broken by an air cannon actual hit test at a distance of 2 m, an initial speed of 54 m / sec, and 500 rounds. 16. A golf shaft according to claim 15, wherein the epoxy resin composition according to any one of claims 1 to 13 is used.