JPH0770409A - Low temperature curing epoxy resin composition for prepreg and prepreg using the same - Google Patents

Abstract

PURPOSE:To provide the composition comprising an epoxy resin, a specific low temperature curing agent and an inorganic filler having a specified average particle diameter in a specific composition ratio, excellent in storage stability and in permeability into reinforcing fibers, providing cured products good in strength and surface, and useful for prepregs, etc. CONSTITUTION:(A) 100 pts.wt. of an epoxy resin (e.g. bisphenol A epoxy resin), (B) a low temperature curing agent comprising the combination of dicyandiamide and an urea derivative of the formula (R, R' are H, Cl, Br, lower alkyl, lower alkoxy), etc., exhibiting a latent curing property at the ordinary temperature and having a reaction-starting temperature of 40-115 deg.C in an amount of 0.2-3 times equivalent per equivalent of the component A, and (C) 3-50 pts.wt. of an inorganic filler (e.g. calcium carbonate) having an average particle diameter of 0.1-10mum to obtain the epoxy resin composition. The resin composition is coated on a sheet, mixed with a reinforcing material and heated at 50-70 deg.C to obtain an epoxy resin prepreg in which the viscosity of the matrix resin composition is 1000-1000000 cps at 50 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low temperature curable epoxy resin composition for a prepreg, which is capable of obtaining a molded product having excellent storage stability of a resin and excellent bending strength and surface properties, and a prepreg using the same. .

[0002]

2. Description of the Related Art Epoxy resin is the heat resistance of the cured product,
It is excellent in elastic modulus, hardness, chemical resistance and the like, and is widely used as a resin composition for prepreg, in which reinforced fibers such as aramid fiber, glass fiber and carbon fiber are particularly used. Such prepregs are widely used in various technical fields, and are particularly often used in the production of golf club shafts, fishing rods, tennis racket frames, skis, etc. because of their light weight and high mechanical strength. There is.

Conventionally, prepregs are manufactured according to their manufacturing method.
Solvent type that uses a low viscosity impregnating liquid using a solvent as a resin composition for prepreg, without using a solvent,
There are a hot-melt type that uses a high-viscosity type that fluidizes at a certain temperature, and a room-temperature-impregnated type that uses a low-viscosity resin that is fluid at room temperature without using a solvent.

Solvent-type prepregs are used for molding the above-mentioned respective sports members. However, since solvent-type prepregs use a solvent, storage stability and prepreg handling are poor due to the progress of the reaction. There are problems that the physical properties and surface finish of FRP molded products vary and the working environment is bad. Further, since the room temperature impregnated type has a low initial viscosity and cannot be impregnated into a uniform thickness,
The surface properties and handling properties are poor, and it is necessary to increase the viscosity from a low viscosity of about 1000 cps to a high viscosity of about 100,000 cps, and since the viscosity increase width is large, it is difficult to control the reaction, and the physical properties of the resulting prepreg There is a drawback that variations occur.

On the other hand, the hot-melt type has advantages such as good storage stability, easy control of handleability of the prepreg, and production of a clean prepreg free from a solvent. Due to the advantages of significantly improving production efficiency and enabling low-temperature integral molding with a core material having low heat resistance, a hot-melt type low-temperature fast-curing prepreg is desired.

However, in the current use of prepregs in the sports field, not only the development of strength but also the improvement of the surface property of how well and cleanly the surface is formed is a serious problem. Generally, when molding golf heads and other sports fields, a prepreg containing glass fiber or carbon fiber as a reinforcing fiber is attached to the upper surface of the core material to perform integral molding. Has a significant effect on the subsequent polishing and painting processes, as well as the quality of the final product, so how to cleanly mold and cure is a key point of the molding method using prepreg. However, even in a hot-melt type prepreg, a resin composition for prepreg that enables high-temperature-integral molding with a core material having high production efficiency and low heat resistance, and that can obtain a molded article having excellent surface properties, The current situation is that it has not been found yet.

More specifically, in the conventional hot-melt type prepreg, high temperature (120 to 130 ° C.) and long time (1 to 2 hours) are required for curing. Therefore, low temperature rapid curing significantly increases production efficiency and heat resistance. Low temperature integral molding with low core materials is still impossible. Also, the curing is slow,
Since the resin flow continues for a long time, the reinforcing fibers and air bubbles present in the resin gradually rise to the surface, and the surface of the cured product becomes dirty with many voids (poor surface property). In particular, in the case of carbon fiber cloth prepreg used for the surface material of the golf head, many pits are generated at the cross, and repair work (filling putty on the pits) for these is required, resulting in poor surface properties. Causes inefficiency (this also applies to the solvent method).

On the other hand, in the case of using a hot melt type low temperature curing prepreg, the present inventors have made various proposals (for example, Japanese Patent Laid-Open No. 4-325518), but the storage stability is maintained. While low temperature (70-100
Since it can be cured in a short time (about 20 minutes to 1 hour), it is possible to significantly improve the production efficiency and perform low-temperature integral molding with a core material having low heat resistance. Furthermore, the rapid curing tends to significantly improve the surface properties of the cured molded product (makes the finish clean) (cures before the bubbles rise). However, in order to use the same prepreg for molding the above-mentioned respective sports members, particularly for the head portion of the golf club, the arm portion of various rackets, etc., the finished state of the surface is still insufficient (it is necessary to reduce the voids on the surface. ).

[0009]

Therefore, the present invention has been made in view of the circumstances of the above-mentioned prior art, and it is possible to obtain a molded product without impairing the low-temperature reaction characteristics, storage stability, handleability, etc. of the resin. It is an object of the present invention to provide an epoxy resin composition for low temperature curable prepreg in which the surface properties and physical properties of the body (FRP) are significantly improved and a prepreg using the same.

[0010]

According to the present invention, 100 parts by weight of an epoxy resin (A) and the epoxy resin (A) 1
There is a potential at room temperature for the equivalent weight and the reaction start temperature is 40 to 1
Low temperature curing agent (B) which is 15 ° C. 0.2 to 3 times equivalent and inorganic filler (C) 30 to 50 having an average particle diameter of 0.1 to 10 μm
A low temperature curable prepreg epoxy resin composition is provided, wherein the sheet is coated with the low temperature curable prepreg epoxy resin composition, and a reinforcing material is sandwiched from one side or both sides. While doing 50 ~
The matrix resin composition is heated and impregnated at 70 ° C. and has a viscosity of 1,000 to 1,000,0 at 50 ° C.
There is provided an epoxy resin prepreg, which is characterized in that it is 00 cps.

That is, the epoxy resin composition for prepreg of the present invention comprises 100 parts by weight of an epoxy resin, 3 to 50 parts by weight of a low temperature curing agent and 3 to 50 parts by weight of an inorganic filler having an average particle diameter of 0.1 to 10 μm. Moreover, since the matrix resin composition of the prepreg using the composition has a viscosity at 50 ° C. of 1,000 to 1,000,
Since it is 000 cps, the strength of the FRP at the time of curing and molding and the cured product while maintaining the low temperature reaction characteristics and storage stability of the resin, the resin impregnation property to the reinforcing fiber at the time of prepreg production, and the handleability of the prepreg. The surface property of can be greatly improved. The reason for this is that (a) the use of a low-temperature fast-curing resin causes the bubbles to cure rapidly before they float on the surface, and (b) the incorporation of an inorganic filler prevents bubbles from rising to the surface. From the above, the surface property of the obtained molded product is greatly improved, and further, (c) the stress is uniformly dispersed in the highly dispersed inorganic filler, so that the bending strength of the resulting molded product is improved. It is estimated to be. Also, from this,
According to the present prepreg, in the field of molding golf club shafts, heads, various rackets and ski members, it is possible to finish FRP with low temperature and fast curing and high strength with very good surface properties.

The present invention will be described in more detail below. Epoxy resin (A) used in the epoxy resin composition of the present invention
Are, for example, glycidyl ether epoxy resins such as bisphenol A, bisphenol F or bisphenol S epoxy resins, novolac epoxy resins and brominated bisphenol A epoxy resins; cycloaliphatic epoxy resins; glycidyl ester epoxy. Resins; glycidyl amine-based epoxy resins such as tetraglycidyl diaminodiphenylmethane, triglycidyl-p-aminophenol; and heterocyclic epoxy resins can be mentioned. These can be used alone or as a mixture of two or more kinds.

It has a potential at room temperature and a reaction initiation temperature of 40.
As the low temperature curing agent (B) having a temperature of up to 115 ° C., for example,
A curing agent compound obtained by heating and reacting an amine compound, an epoxy resin, and urea described in JP-A-3-177418.
Examples thereof include a curing agent obtained by microencapsulating an amine compound described in JP-A-64-70523. The use ratio of the low temperature curing agent (B) is 0.2 to 3 times equivalent to 1 equivalent of the epoxy resin (A). If it is less than 0.2 times equivalent or more than 3 times equivalent, curing is insufficient and the resulting prepreg exhibits insufficient characteristics.

The reaction initiation temperature referred to in the present invention is D
The temperature is raised at a temperature rising rate of 10 ° C./mm by using SC, and the on se obtained from the exothermic curve as shown in FIG. 1, for example.
t means temperature.

In addition, it is preferable to add dicyandiamide and a urea derivative represented by the following general formula 1 to the low temperature curing agent system of the present invention, if necessary, in order to improve the strength of FRP during curing molding.

[Chemical 1] (In the formula, R and R'represent a hydrogen atom, a chlorine atom, a bromine atom, a lower alkyl group or a lower alkoxy group, and R and R '
May be the same or different. ) Specific examples of this urea derivative include the following. 3- (3,4-
Dichlorophenyl) -1,1-dimethylurea, 3-phenyl-1,1-dimethylurea, 3- (3,4-dimethylphenyl) -1,1-dimethylurea, 3- (P-chlorophenyl) -1,1 -Dimethylurea etc. The appropriate proportion of dicyandiamide used is 1.0 to 10 parts by weight, preferably 2 to 8 parts by weight, based on 100 parts by weight of the epoxy resin (A). The proportion of the urea derivative represented by the general formula 1 is appropriately 1 to 10 parts by weight, preferably 2 to 8 parts by weight, based on 100 parts by weight of the epoxy resin (A).

Further, in the present invention, an inorganic filler (C) having an average particle diameter of 0.1 to 10 μm (preferably 0.5 to 5 μm) is added to the low temperature curing epoxy resin composition. Specific examples of the inorganic filler (C) include calcium carbonate (average particle size 0.1 to 10 μm), talc (average particle size 0.1 to 10 μm), mica (average particle size 0.1 to 10).
μm), alumina or aluminum hydroxide (average particle size of 0.1.
1 to 10 μm) and the like. If the average particle size of the added inorganic filler exceeds 10 μm, the bending properties of the FRP tend to deteriorate and the surface properties of the FRP cannot be improved.
On the other hand, when the average particle diameter is less than 0.1 μm, the viscosity of the resin increases significantly with the addition, and it becomes difficult to form prepreg. Average particle size 0.1 to 10 μm, preferably 0.5 to 5
When the inorganic filler having a thickness of μm is used, the effect of improving the strength and surface property of the FRP based on the high dispersion of the filler in the resin is great.

The addition ratio of the inorganic filler (C) is 3 to 50 parts by weight with respect to 100 parts by weight of the epoxy resin (A),
It is preferably 5 to 30 parts by weight. If the amount added exceeds 50 parts by weight, the viscosity of the resin becomes extremely high and it cannot be used as a resin for prepreg. On the contrary, if the addition amount is less than 3 parts by weight, the effect of improving strength and surface property is not obtained.

In the present invention, examples of the sheet (support) coated with the epoxy resin composition include release paper, release film, metal foil and the like. The release paper is preferably used because it has releasability and has heat resistance and strength that can withstand the temperature and tension in the prepreg manufacturing process.

The reinforcing fibers used in the prepreg of the present invention include, for example, glass fibers, carbon fibers, mica, asbestos, synthetic resin fibers, or woven or non-woven fabrics thereof. These reinforcing fibers are used in a fiber content of 20 to 70% with respect to the epoxy resin composition.

Further, in the epoxy resin composition for prepreg of the present invention, various additives such as a filler, a coloring agent and a diluent may be blended within a range not losing the various properties.

To produce the prepreg of the present invention, for example, first, a sheet is coated with the matrix resin composition for prepreg comprising the above epoxy resin to produce a resin-coated sheet. Next, the two resin-coated sheets are made to face each other with the resin-coated surface facing each other, a reinforcing material is sandwiched therebetween, and a hot press roller or the like is heated to room temperature to 70 ° C. under pressure and impregnated, and then the sheets are impregnated. The desired prepreg can be obtained by removing.

The viscosity of the obtained prepreg matrix resin composition at 50 ° C. is 1,000 to 1,000,
000 cps, preferably 50,000 to 300,000
cps. 1,0 even if lower than 1,000 cps
Even if it is higher than 0,000 cps, the handleability of the prepreg is remarkably poor.

[0023]

EXAMPLES Next, the present invention will be described in more detail by way of examples. All parts shown below are based on weight.

Example 1 <Preparation of prepreg (hot melt type)> On release paper,
An epoxy resin composition for prepreg having the following composition was coated at 65 ° C., and carbon fiber cloth as a reinforcing fiber [T300, FAW20 manufactured by Toray Industries, Inc.]
0 g / m ² ], with a carbon fiber content of 45% by weight
Was laminated at 70 ° C. to produce a prepreg.

<Resin Composition> Epicoat 828 40 parts [Bisphenol A epoxy resin manufactured by Yuka Shell Co., Ltd.] Epicoat 1001 60 parts [Bisphenol A epoxy resin manufactured by Yuka Shell Co., Ltd.] HX3722 20 parts [Asahi Kasei Low temperature curing agent manufactured by Co., Ltd., reaction initiation temperature 112 ° C.] Note that 20 parts of HX3722 is 0.7 equivalent to 100 parts of epoxy resin consisting of 40 parts of Epicoat 828 and 60 parts of Epicoat 1001. DICY (dicyandiamide) 4 parts DCMU 4 parts [3- (3,4-dichlorophenyl) -1,1-dimethylurea] calcium carbonate A (average particle size 3 μm) 5 parts

<Resin Viscosity and Handling Property of Prepreg> The 50 ° C. viscosity of the obtained prepreg matrix resin composition was measured and the handling property of the prepreg was evaluated. The results are shown in Table 2.

<Strength and surface property of molded body> The obtained prepreg is cut and laminated so as to have a thickness of 2 mm,
It was cured and molded at 90 ° C. for 1 hour using a hot press machine. The bending properties of the obtained molded product are shown in Table 2. The method for measuring the bending properties is as follows. Bending strength and elastic modulus (based on ASTM D790-80) -Test piece size: 2 x 12.7 x 120 mm-Jig radius: indenter 3.2 mm fulcrum 3.2 mm-distance between fulcrums: 32 mm (test piece thickness 2. 0 mm 16
・ Test speed: 3.0 mm / min Also, in order to investigate the surface properties of the prepreg during curing,
Two prepregs are laminated separately, and 1.
The number of open pits on the surface of the cured product when formed at a pressure of 5 kg / cm ² was counted. The results are shown in Table 2.

Examples 2 to 3 The amount of calcium carbonate A which is an inorganic filler was 10 parts and 3 parts.
An epoxy resin composition for prepreg was prepared in the same manner as in Example 1 except that the content was 0 part, and the prepreg and the molded product were manufactured and evaluated using the epoxy resin composition.

Examples 4 to 6 Epoxy for prepreg was prepared in the same manner as in Example 1 except that the inorganic filler was talc A (average particle size 4 μm) and the addition amount was 5, 10, and 30 parts. A resin composition was prepared, and a prepreg and a molded body were manufactured using the resin composition and evaluated.

Examples 7 to 8 The low temperature curing agent was FXE1000 [low temperature curing agent manufactured by Fuji Kasei Co., reaction start temperature 92 ° C .; see FIG. 1] -20 parts (1 equivalent equivalent to 100 parts of epoxy resin). The epoxy resin composition for prepreg was prepared in the same manner as in Example 1 except that 30 parts of calcium carbonate A and 30 parts of talc A were prepared, and the epoxy resin composition for prepreg was prepared using the epoxy resin composition. It was manufactured and evaluated.

Example 9 An epoxy resin composition for prepreg was prepared in the same manner as in Example 3 except that DICY and DCMU were not used, and the prepreg was produced and molded by using the epoxy resin composition. Was manufactured and evaluated.

Example 10 An epoxy resin composition for a prepreg was prepared in the same manner as in Example 6 except that DICY and DCMU were not used, and the epoxy resin composition for prepreg was used to produce and mold a prepreg. Was manufactured and evaluated.

Comparative Example 1 An epoxy resin composition for prepreg was prepared in the same manner as in Example 1 except that the low temperature curing agent and the inorganic filler were not used. The production and the molding were conducted and evaluated.

Comparative Example 2 In Example 1, no inorganic filler was used (ie,
An epoxy resin composition for prepreg was prepared in the same manner as in Example 1 except that the conventional low temperature curable resin composition was used, and the prepreg and the molded product were manufactured and evaluated using the epoxy resin composition.

Comparative Examples 3 to 4 An epoxy resin composition for prepreg was prepared in the same manner as in Example 1 except that the amounts of calcium carbonate A added were 2 parts and 60 parts (outside the claims). Was prepared, and a prepreg and a molded product were manufactured and evaluated using it.

Comparative Examples 5 to 7 In Example 4, the low temperature curing agent was FXE1000-20.
Parts, and except that the addition amount of talc A was 2, 60 and 80 parts (outside the claims), an epoxy resin composition for prepreg was prepared and used in the same manner as in Example 4. The prepreg and the molded product were manufactured and evaluated.

Comparative Examples 8 to 9 In Example 1, calcium carbonate A-5 parts was added to talc B.
(Average particle size 20 μm) -30 parts and calcium carbonate B
(Average particle size 16 μm), except that the content is changed to −30 parts.
An epoxy resin composition for prepreg was prepared in the same manner as in Example 1, and the prepreg and the molded product were manufactured and evaluated using the epoxy resin composition.

Comparative Example 10 An epoxy resin composition for prepreg was prepared in the same manner as in Comparative Example 4 except that DICY and DCMU were not used in Comparative Example 4, and the prepreg was manufactured and molded using the same. Was manufactured and evaluated.

Comparative Example 11 An epoxy resin composition for prepreg was prepared in the same manner as in Comparative Example 6 except that DICY and DCMU were not used in Comparative Example 6, and the prepreg was manufactured and a molded product was prepared. Was manufactured and evaluated.

Comparative Example 12 An epoxy resin composition for prepreg was prepared in the same manner as in Example 5 except that talc C (average particle size 0.05 μm) was used as the inorganic filler. Using it, a prepreg and a molded body were manufactured and evaluated.

Comparative Example 13 An epoxy resin composition for prepreg was prepared in the same manner as in Example 6 except that talc C (average particle size 0.05 μm) was used as the inorganic filler. Using it, a prepreg and a molded body were manufactured and evaluated.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

The epoxy resin composition for prepreg of the present invention comprises 100 parts by weight of an epoxy resin and 0.2 parts of a low temperature curing agent.
.About.3 times equivalent weight and 3 to 50 parts by weight of an inorganic filler having an average particle size of 0.1 to 10 .mu.m, the prepreg matrix resin composition using the composition has a viscosity at 50.degree. 1,000-1,000,000
Since it is cps, the low temperature reaction characteristics of the resin, storage stability, coating property, resin impregnation property to the reinforcing fiber at the time of prepreg production, prepreg handleability, while maintaining the strength of FRP during curing molding In addition, the surface property of the cured product can be greatly improved. Also,
From this, according to the present prepreg, in the field of molding golf club shafts, heads, various rackets, and ski members, it becomes possible to finish FRP with low temperature and fast curing and high strength with very good surface properties.

[Brief description of drawings]

FIG. 1 is a low temperature curing agent FXE-1000 used in Example 7.
It is a graph which calculates the reaction start temperature of [Fuji Kasei].

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Takezawa 1-3-1, Nishitsurugaoka, Oi-cho, Iruma-gun, Saitama Tonen Research Institute

Claims (2)

[Claims] 1. A low temperature curing agent (B) having 100 parts by weight of an epoxy resin (A) and 1 equivalent of the epoxy resin (A) and having a latent property at room temperature and a reaction initiation temperature of 40 to 115 ° C.
An epoxy resin composition for low-temperature curable prepreg, which comprises 0.2 to 3 times equivalent weight and 3 to 50 parts by weight of an inorganic filler (C) having an average particle diameter of 0.1 to 10 μm. 2. A sheet is coated with the epoxy resin composition for low temperature curable prepreg according to claim 1 and is heated and impregnated at 50 to 70 ° C. while sandwiching a reinforcing material from one side or both sides. Of the matrix resin composition at 50 ° C
An epoxy resin prepreg having a viscosity of 1,000 to 1,000,000 cps.