JPH0812851A - Epoxy resin composition - Google Patents

Abstract

(57) [Summary] [Structure] The following (A), (B), (C), (D) and (E) components (A) epoxy resin (B) thermoplastic resin (C) latent amine curing agent (D) Curing accelerator (E) An epoxy resin composition comprising a fibrous inorganic filler having an aspect ratio of 3 or more. [Effect] A fiber-reinforced resin composite material with few defects can be obtained,
Improves reliability and productivity.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is excellent in handling workability such as proper tackiness (adhesiveness) and drapeability (flexibility) of prepreg and storage stability at room temperature, and has a small resin flow during molding. , Especially suitable for fiber reinforced composite materials having excellent composite material properties, such as a tubular molding made of fiber reinforced resin such as fishing rods and golf shafts, which does not fall down during molding, and there are no defects such as scratches on the polished surface of these moldings The present invention relates to an epoxy resin composition used in.

[0002]

2. Description of the Related Art A fiber-reinforced composite material having carbon fiber as a reinforcing material is lightweight, has high strength and high elastic modulus, and is in the form of a composite with a resin, so-called prepreg, such as a fishing rod and a golf club. Shafts, sports such as tennis rackets
Leisure field, industrial materials such as leaf springs and honeycomb structure materials,
Furthermore, automobile-related, aircraft materials, structural materials for ships, etc.
Widely used for various purposes such as electronic materials and civil engineering and construction materials.

By the way, as a matrix resin of such a prepreg for a fiber-reinforced composite material, an epoxy resin as a main component, a rubber component (JP-A-60-39286) or a thermoplastic resin (JP-A-62-169829) has been used.
JP-A No. 63-221122) and the like are used for producing a prepreg.

Particularly for tubular fiber-reinforced composite materials such as fishing rods and golf shafts, a sheet-shaped prepreg in which carbon fibers or glass fibers are aligned in one direction or a prepreg obtained by impregnating a woven fabric of the above-mentioned reinforcing fibers with a matrix resin is released. Wrap the taped mandrel coated with the agent in the longitudinal direction in the direction according to the desired design, and then wind the heat-shrinkable tape spirally using a tape winder, etc. while gradually overlapping it. Then, put it in a heating furnace, harden the matrix resin while applying tightening force with heat shrinkable tape, remove from the heating furnace and remove the tape after cooling, pull out the mandrel with a core removing machine etc. . However, the conventional prepreg has a drawback that the prepreg moves from the large diameter side of the mandrel toward the small diameter side during molding, that is, so-called furnace drop occurs. This is because heating causes the matrix resin to have low viscosity and to increase fluidity, so when the tightening force of the heat-shrinkable tape is applied in such a state, the mandrel has a taper, and the mandrel has a taper from the large diameter side to the small diameter side. A component force is generated and a so-called furnace drop occurs in which the prepreg moves in this direction. When this furnace drop occurs, the distribution of the matrix resin and the reinforcing fibers becomes uneven, and the desired physical properties of the composite material cannot be obtained, and it also causes defects in the molded product or warpage of the small diameter portion.

On the other hand, Japanese Patent Application Laid-Open No. 57-22636 discloses that
Prior to winding the prepreg around the mandrel, a method has been proposed in which a thread or a thread impregnated with a thermosetting resin is spirally wound in the longitudinal direction of the mandrel and the friction thereof prevents the furnace from falling. However, in this method, not only the effect of preventing the furnace from falling is not sufficient, but also the yarn remains in the molded product, which is not preferable in terms of characteristics. Further, in JP-A-59-159315, prior to winding the prepreg around the mandrel,
It has been proposed to prevent a furnace from falling by coating a mandrel with a thermosetting resin having a gel time at 130 ° C. of 80% or less of the resin for a prepreg matrix resin. However, this method requires a resin for undercoating, the gel time of which is adjusted by B-stage formation, and the step of applying the undercoating resin and air drying are required prior to molding, resulting in a marked decrease in productivity.

Further, regarding the handling property (tack and drape property) of the prepreg at the time of working, not only the productivity at the time of shaft winding but also the cause of defects (scratches, etc.) on the surface of the molded product are required to have appropriate characteristics. To be done. These properties require a prepreg that is less affected by working temperature and has less temperature dependence. If the tackiness is too strong, air is likely to be entrained at the time of winding, and if it is too low, workability such as laminating the prepreg deteriorates. In addition, when the drape property is insufficient, the prepreg is wound at the end portion of the winding, and particularly carbon fibers having a high elastic modulus may be broken. However, these factors appear on the surface as defects such as scratches at the time of polishing and coating after molding the shaft, causing defective products and deteriorating the physical properties, resulting in a significant reduction in yield.

As described above, the prepreg using the conventional matrix resin composition has appropriate workability and excellent composite material properties, does not fall down during molding, and is capable of polishing molded products.
It has been extremely difficult to provide a prepreg with no defects on the coated surface.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks of the conventional method, prevent the furnace from falling during molding without performing a pretreatment step, and deteriorate the composite material properties. To obtain a fiber-reinforced composite material molded article having desired properties. Moreover, the prepreg using the epoxy resin composition of the present invention has a normal winding temperature (20 to
At 30 ° C), it has an appropriate winding workability with little temperature dependence, and the resin flow during molding can be controlled freely, so there is no defect (scratches, etc.) on the surface of the molded product after polishing. The present invention provides a molded product.

[0009]

Means for Solving the Problems That is, the present invention provides the following components (A), (B), (C), (D) and (E) (A) epoxy resin (B) thermoplastic resin (C) latent Amine amine curing agent (D) Curing accelerator (E) An epoxy resin composition containing a fibrous inorganic filler having an aspect ratio of 3 or more as an essential component.

The epoxy resin which is the component (A) used in the present invention is not particularly limited, and includes bisphenol A type epoxy resins and other glycidyl ether type epoxy resins such as bisphenol F type epoxy resins and bisphenol S type. Epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, glycidyl amine type epoxy resin, naphthalene type epoxy resin, brominated bisphenol A type epoxy resin, glycidyl ester type epoxy resin, cycloaliphatic epoxy resin, heterocycle Formula epoxy resin etc. are mentioned. If desired, urethane-modified epoxy resin, rubber-modified epoxy resin, alkyd-modified epoxy resin, etc. may be used. Among these, bisphenol A type epoxy resin and novolac type epoxy resin are preferable from the viewpoint of balance of handling property, economical efficiency, and physical properties of composite material, but two or more kinds of these can be appropriately mixed and used according to required characteristics.

The thermoplastic resin as the component (B) includes, for example, phenoxy resin, polyvinyl butyral, polyvinyl formal, polyvinyl phenyl acetal and other acetal resins, polyether sulfone, polysulfone, polyether imide, polyarylate and the like. It is not limited. These resins change the viscosity characteristics of the epoxy resin composition and contribute to the improvement of prepreg handleability in a wide temperature range. One or two or more of these resins are appropriately used, and 1 to 40 parts by weight, preferably 1 to 20 parts by weight are used with respect to 100 parts by weight of the component (A). If it is less than 1 part by weight, the effect of improving the viscosity characteristics is small, and if it is 20 parts by weight or more, the viscosity of the resin composition on the high temperature side becomes high, and in the prepreg forming step by the hot melt method,
Impregnability into the fiber reinforcement is likely to decrease.

Examples of the latent amine-based curing agent as the component (C) include dicyandiamide (1-cyanoguanidine), methylguanidine, ethylguanidine, propylguanidine, butylguanidine, dimethylguanidine,
Guanidine-based curing agents such as trimethylguanidine, phenylguanidine, diphenylguanidine, toluylguanidine, 2,3-guanylurea, benzoyldicyandiamide, 2,6-xylenylbiguanide and phenylbiguanide can be mentioned. Further, for example, adipic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, sebacic acid hydrazide, oxalic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, p-oxybenzoic acid hydrazide, salicylic acid hydrazide, and
Examples thereof include polyhydric carboxylic acid polyhydrazide-based curing agents such as dimer acid dihydrazide and azelaic acid dihydrazide. These latent amine curing agents can be used alone or in combination of two or more depending on the required properties.
However, dicyandiamide and adipic acid dihydrazide are preferable from the viewpoints of storage stability, economical efficiency, and physical properties of composite materials. If desired, various curing agents can be used in combination. For example, boron trifluoride amine complex, amine imide, diaminomaleonitrile, guna amines, phenol resin, melamine resin, urea resin and the like can be mentioned. The amount of these curing agents used is usually such that the active hydrogen equivalent of the curing agent is around 0.2 to 1.2 equivalents relative to 1 equivalent of the epoxy group, although the physical properties of the cured product are good, but the storage stability is good. Etc. are adjusted as appropriate according to other required characteristics. Usually, 1 to 40 parts by weight, preferably 1 to 20 parts by weight is suitable for 100 parts by weight of the components (A) and (B). If it is less than 1 part by weight, the curing tends to be insufficient, and if it is more than 20 parts by weight, the properties of the cured product are likely to deteriorate.

Incidentally, the latent curing agent is one which does not work as a curing agent at a certain temperature or lower, but does not work as a curing agent at a certain temperature or higher.
What happens above.

Examples of the curing accelerator of the component (D) include imidazole derivatives and salts thereof (for example, "Cureazole" manufactured by Shikoku Kasei), amine adduct compounds (for example, "Amicure" manufactured by Ajinomoto Co.), and microcapsules (for example, Asahi Kasei). "Novacure" manufactured by the company), urea compounds (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, trimethylurea) and the like show excellent effects. The addition amount of these curing accelerators is 1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the components (A) and (B). If the amount is less than 1 part by weight, the curing acceleration effect tends to be small, and if the amount is more than 10 parts by weight, the storage stability of the prepreg tends to decrease.

The fibrous inorganic filler as the component (E) has an aspect ratio (fiber length / fiber diameter) of 3 or more. If the aspect ratio is small, the resin flow during molding will not be sufficiently low, and the aspect ratio will be limited to 3 or more. The upper limit value is preferably 500 or less, more preferably 400 or less. Examples of these fibrous inorganic fillers include wollastonite, sepiolite, asbestos, slag fibers and the like in the natural product type, and zonolite, potassium titanate, elestadite, gypsum fiber and the like in the artificial type. The addition amount of these fibrous inorganic fillers is 0.05 to 20 parts by weight, preferably 0.5 to 1 part by weight with respect to 100 parts by weight of the components (A) and (B).
0 parts by weight are used. When the amount is 0.5 parts by weight or less, the flow during molding is not sufficiently reduced, and when the amount is 10 parts by weight or more, the viscosity of the resin increases, and the impregnation property into the fiber in the prepreg-forming step tends to decrease.

In addition to the above components, if desired, an epoxide-reactive diluent may be added to the extent that reactivity, heat resistance, toughness, storage stability and the like are not deteriorated. Examples of reactive diluents include phenyl glycidyl ether, butyl glycidyl ether, alkyl glycidyl ether,
Examples thereof include styrene oxide, octylene oxide and mixtures thereof. In addition, silanes, coupling agents such as titanate compounds, release agents such as higher fatty acids and waxes, flame retardants such as halogens and phosphorus compounds,
Additives such as defoaming agents and coloring agents can also be used if necessary.

The reinforcing fibers used for producing a prepreg using the epoxy resin composition of the present invention include carbon fiber, glass fiber, aramid fiber, polyester fiber,
Examples thereof include silicon carbide fiber, boron fiber, alumina fiber, polyethylene fiber and the like, and one kind or two or more kinds thereof are appropriately used. In order to produce a prepreg, a general prepreg production method can be applied, and either the hot melt method is used to impregnate the reinforcing base material directly or by the film method, or the solvent impregnation method is used either directly or after film formation. However, the solvent impregnation method requires a solvent distillation step.

[0018]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. The abbreviations of the compounds used in the examples and the test methods are as follows.

<Raw material>"E828": Bisphenol A type epoxy resin (made by Yuka Shell Co., Ltd.) "E1001": Bisphenol A type epoxy resin (made by Yuka Shell Co., Ltd.) "DEN438": Phenol novolac type epoxy resin (Dow Chemical Co., Ltd.) “YP50P”: Phenoxy resin (Toto Kasei Co., Ltd.) PVF: Polyvinyl formal, Vinylex L (Chisso Co.) DICY: Dicyandiamide (Okaka Shell Co., Ltd.) DCMU: 3- (3,4-dichlorophenyl) -1,1
-N dimethyl urea (Hodogaya Chemical Co., Ltd.) "Milcon PS": Sepiolite (Showa Mining Co., Ltd.) (aspect ratio 50) "R202": Fine silica, "Aerosil R202"
(Made by Nippon Aerosil Co., Ltd.)

<Resin Viscosity> Apparatus: Using "RDS-II" manufactured by Rheometrics,
The temperature was raised at 2 ° C / min and the viscosity at 40 ° C (η40 ° C) and the minimum viscosity (ηmin) were measured.

<Measurement of resin flow> 10 prepregs
Cut to 0 x 100 mm and stack 4 plies,
After laminating a film with holes on the top and bottom and glass cloth on the outermost layer, press the resin at 120 ° C and 3.5 kg / cm ² with a heating press to measure the resin flow.

<Evaluation of Winding and Furnace Falling> A prepreg was used as an oblique layer (± 45 °) 3 plies and a straight layer (0 °) 3
Cut into plies. The cut prepreg was wound on a mandrel coated with a release agent by a rolling table. The heat shrink tape was then wrapped with a tape wrapping machine. Suspend in a heating furnace with the large diameter side up, 12
Cured at 0 ° C./2 hours. After cooling to room temperature, measure the furnace falling.

<Handling workability: tackiness, drapeability> (Comprehensive judgment based on the laminated state of the oblique layer at 23 ° C., correctability, manual winding hardness, and shaving after rolling table winding) ○ …… Good, × …… Poor

<Bending test (3-point bending)> ASTM D7
Device according to 90: "UTM" manufactured by Toyo Baldwin
-5T ", sample shape: (length 100 mm, width 10 mm, thickness 2 mm), span length: 80 mm, crosshead speed: 2 mm / min.

<ILSS> According to ASTM D2344, sample shape: (length 12 mm,
Width 10 mm, thickness 2 mm), span length: 8 mm, crosshead speed: 2 mm / min.

(Example 1) 15 parts by weight of "E828" (excluding the amount used for the masterbatch) and 3 parts of "E1001"
6 parts by weight, 34 parts by weight of “DEN438” were melt mixed at 80 ° C., the temperature was raised to 150 ° C., 8 parts by weight of “YP50P” was added and dissolved by stirring for 1 hour, and cooled to room temperature to obtain a base resin. It was 4 parts by weight of DICY on this base resin,
5 parts by weight of "Milcon PS" was added in a masterbatch, and the mixture was uniformly mixed with a stirrer at 70 ° C for 30 minutes. Then, 3 parts by weight of DCMU was added and stirred for 10 minutes to obtain a resin composition of the present invention. The resin composition thus obtained and carbon fiber (“Torayca T300” manufactured by Toray Industries, Inc., elastic modulus 24 to
n / mm ² ) and a unidirectional prepreg was produced by the hot melt method to obtain the prepreg of the present invention. The carbon fiber basis weight of this prepreg was 150 g / m ² , and the resin amount was 35%. 14 plies of this prepreg are laminated in one direction,
Approximately 2m by curing at 120 ℃ / 2 hours in an autoclave
An m-thick unidirectional laminate was formed. Table 1 shows the physical properties (Vf = 60% conversion value) of the obtained composite material.

Then, the winding evaluation was performed at 23 ° C. and 30 ° C. This prepreg had no temperature dependency and had very good handling workability (tack and drape). The 10 molded articles obtained did not have any furnace falling. Furthermore,
The surface of this molded product was polished with a polishing machine and observed for surface defects (scratches, etc.), and good molded products without any defects were obtained.

Example 2 A method similar to that of Example 1, Table 1
A resin composition of the present invention was obtained with the above composition. The workability of this prepreg is good, and the molded product does not fall down from the furnace,
No defects were observed on the polished surface.

(Examples 3 and 4) PVF was added to the component (B) in an amount of 3 parts by weight or 5 parts by weight in the same manner as in Example 1 except that the components were dissolved and mixed at 165 ° C for 3 hours. A prepreg was manufactured. The workability of the prepreg was good, and no defects were observed in the molded product.

(Comparative Example 1) According to the composition of Table-1, (B)
A prepreg was produced by the same method as in Example 1 except that the component and the component (D) were not used. The basis weight of the prepreg was 150 g / m ² and the resin amount was 35%. This prepreg had high tackiness, large resin flow, and the furnace fell. In addition, scratches on the polished surface of the molded product were also noticeable.

(Comparative Example 2) (B) without using the component (D)
A prepreg was produced by the same method as in Example 1 except that 5 parts by weight of PVF was used as a component. This prepreg had relatively good workability, but the resin flow was large and the furnace fell. Also, scratches were generated on the polished surface of the molded product.

(Comparative Examples 3 and 4) A prepreg was produced in the same manner as in Example 1 except that the component (B) was not used and the aerosol filler R202 or the component (D) was used as the inorganic filler. The temperature dependence of these prepregs during winding is high,
The workability at was poor.

[0033]

[Table 1]

[0034]

The prepreg manufactured from the matrix resin containing the fibrous inorganic filler according to the present invention can be adjusted in appropriate workability and resin flow at the time of molding freely. A molding having no defects and excellent composite material properties can be obtained by a molding method such as molding, which is extremely useful for improving reliability and productivity of the fiber-reinforced composite material.

Claims (5)

[Claims] 1. The following (A), (B), (C), (D),
And (E) component (A) epoxy resin (B) thermoplastic resin (C) latent amine curing agent (D) curing accelerator (E) containing a fibrous inorganic filler having an aspect ratio of 3 or more. A characteristic epoxy resin composition. 2. The epoxy resin composition according to claim 1, wherein the thermoplastic resin as the component (B) is a phenoxy resin. 3. The epoxy resin composition according to claim 1, wherein the thermoplastic resin as the component (B) is polyvinyl formal. 4. The epoxy resin composition according to claim 1, wherein the latent amine curing agent of component (C) is dicyandiamide. 5. The epoxy resin composition according to claim 1, wherein the fibrous inorganic filler of the component (E) is sepiolite.