JP6937763B2 - Fiber reinforced plastic molding material, its manufacturing method and molded product - Google Patents

Description

The present invention relates to a fiber-reinforced plastic molding material which is excellent in handleability, storage stability and moldability, and which can significantly shorten the molding time, a method for producing the same, and a molded product.

Fiber reinforced plastic (FRP), which is a composite material of fibers such as glass fiber and carbon fiber, has long been used for sports and leisure such as tennis rackets, bicycles, and fishing rods, taking advantage of its lightweight, high-strength, and high-rigidity characteristics. The material used. In recent years, the use of fiber-reinforced plastic materials has been steadily expanding, from housings for electronic devices such as notebook PCs and tablets, to arms for industrial robots, and from consumer devices such as reinforcing materials for building structures. It has been expanded to industrial equipment.

Furthermore, due to the recent rise in crude oil prices and the growing awareness of environmental conservation around the world, energy saving and resource saving are strongly required. In particular, transportation equipment such as automobiles and aviation equipment that use fossil fuels have low fuel consumption. The conversion is being actively promoted. Since the fuel efficiency of transportation equipment is greatly reduced by reducing the weight of the vehicle body and the airframe, FRP using carbon fiber is being used in place of the metal material for these purposes.

The FRP material is produced by impregnating a reinforcing fiber base material with a liquid matrix resin composition and curing it. The liquid resin composition to be impregnated with a reinforcing fiber base material is mainly thermosetting an epoxy resin or the like. A sex resin is used because of the ease of impregnating the fiber base material with the resin composition. However, when a thermosetting resin is used as the matrix resin, it is generally indispensable to use a curing agent together, so that the storage load of such a mixture is large and there is no recyclability like a metal material. Has become a problem, and there is a strong demand for improvement. As a material for FRP molding, a prepreg in which a thermosetting resin is dissolved in a solvent together with a curing agent, impregnated into a reinforcing fiber base material, and then kept in a heat semi-cured (B stage) state is widely used. There was the above-mentioned problem.

Therefore, in Patent Document 1, a solid epoxy resin having a softening point of 50 ° C. or higher and a melt viscosity of 150 ° C. by a cone plate type viscometer of 500 mPa · s or less and a bisphenol type solid epoxy other than the solid epoxy resin are used. A resin, a tetracarboxylic dianhydride, and a curing accelerator are melt-kneaded to obtain an epoxy resin composition, and then the obtained epoxy resin composition is crushed into a powder, and the powder is made into a reinforcing fiber. We have proposed an FRP molding prepreg that can obtain an FRP molding material with excellent storage stability, handling workability, and safety, as well as good mechanical strength and heat resistance, by applying it to a base material and then heating and melting it. However, this method requires the use of two different types of solid epoxy resins in combination, and also uses a curing agent. Therefore, as seen in the examples, the curing time is 1 even if a curing accelerator is used. Since the time is long and the Tg of the cured matrix resin is 150 ° C. or lower, the heat resistance is also insufficient.

On the other hand, a method of solving the problem by using a thermoplastic resin that does not require a curing reaction as the matrix resin instead of the thermosetting resin is also considered. For example, Patent Document 2 proposes an FRP prepreg impregnated with a low molecular weight, non-changeable polyamide resin by contacting a reinforced base material in a powder state. However, since the polyamide resin used has a low molecular weight, the mechanical properties of FRP are rather low, and the molding temperature is as high as 290 ° C., so it takes time to raise and lower the temperature, and the FRP molded product is highly productive. Not suitable for manufacturing.

Further, Patent Document 3 discloses a novel phenoxy resin having high moldability and high heat resistance, and impregnates a reinforcing fiber base material by a hot melt method or a solvent method to impregnate an FRP prepreg for molding processing. It is described to manufacture. However, this method requires a special fused ring structure-containing phenoxy resin, and this condensed ring structure-containing phenoxy resin has a glass transition temperature (Tg) of a molded product of about 150 ° C. at the maximum, so that it is harsh in automobiles and the like. It is insufficient to be applied to members used in various environments.

As described above, as a material for FRP molding, a material that can be melted at a relatively low temperature and can significantly reduce the molding time (high moldability and high productivity) is required, while the obtained molded product is It is also required to have high properties (high toughness, high heat resistance, long life) that can be used even in harsh environments.

Therefore, a method of increasing the Tg of a low Tg thermoplastic resin by a cross-linking reaction using heat during molding is currently being considered. For example, Patent Document 4 discloses a phenoxy resin composition capable of causing a cross-linking reaction and improving heat resistance by adding a cross-linking agent to a thermoplastic resin such as a phenoxy resin or an epoxy resin and applying heat. .. However, although there are examples in which a crosslinked phenoxy resin molded product is obtained from this material, it has not been studied as a material for FRP molding. This phenoxy resin composition also requires a separate heat treatment for 30 to 60 minutes because the heat history at the time of molding is insufficient for the cross-linking reaction to improve Tg, and in the kneading of the materials in the pre-molding stage. Since the reaction with the internal cross-linking agent proceeds and gelation is likely to occur, there is a problem of how to impregnate the reinforcing fiber base material.

Japanese Unexamined Patent Publication No. 2006-232915 Special Table 2012-503693 Japanese Unexamined Patent Publication No. 2010-126694 WO2014 / 157132

An object of the present invention is a material for FRP molding, which has good moldability, which is a characteristic of phenoxy resin, and can suppress a change in mechanical properties in a high temperature environment, which has been a problem due to a cross-linking reaction, and is a harsh environment. However, it is an object of the present invention to provide an FRP molding material capable of obtaining an FRP molded body having high heat resistance and excellent mechanical strength at room temperature and hot water, and a method for producing the same.

As a result of diligent studies to solve this problem, the present inventor has phenoxy resin, which is a reactive thermoplastic resin, as a main component as a component constituting the matrix resin composition, and epoxy resin and compatibility with the phenoxy resin. A material for molding fiber-reinforced plastics, which is made by adhering a matrix resin composition powder containing a high ether group or ester group in the molecule, crushing and blending an aromatic acid anhydride-based cross-linking agent to a reinforcing fiber base material. By doing so, while maintaining good moldability and storage stability, FRP has high mechanical strength at room temperature and hot, and high heat resistance of 160 ° C or higher at Tg that can withstand harsh usage environments. We have found that a molded product can be obtained.

式中、Ｘは、Ｏ、−ＣＨ_２−又は−Ｃ（ＣＨ_３）−を表す。

一般式(2)及び式(3)において、Yは、−（ＣＨ_２）_ｍ−、−（Ph）_ｍ−、−Ph−CH₂−Ph−、又は−Ph−C（CH₃)₂−Ph−を表し、Phはフェニレン基であり、ｍは１から４の整数である。That is, the present invention is a fiber-reinforced plastic molding material composed of a matrix resin composition and a reinforcing fiber base material, wherein the matrix resin composition is a phenoxy resin (A), an epoxy resin (B), and a cross-linking agent (C). Is contained as an essential component, 9 to 85 parts by weight of the epoxy resin (B) is contained with respect to 100 parts by weight of the phenoxy resin (A), and the cross-linking agent (C) is at least represented by the following general formulas (1) to (3). It is one kind of tetracarboxylic acid dianhydride, and the acid anhydride group of the cross-linking agent (C) is in the range of 0.6 to 1.3 mol with respect to 1 mol of the secondary hydroxyl group of the phenoxy resin (A). The matrix resin composition is solid at room temperature, the melt viscosity in any of the temperature ranges of 160 ° C. to 220 ° C. is 3000 Pa · s or less, and the material for fiber-reinforced plastic molding is 20 to 20 to 20 to It is a fiber-reinforced plastic molding material containing 50 wt% and having fine powder of a matrix resin composition adhered to the surface of a reinforcing fiber base material.

In the formula, X represents O, −CH ₂₋ or −C (CH ₃ ) −.

In the general formulas (2) and (3), Y is − (CH ₂ ) _m −, − (Ph) _m −, _{−Ph−CH 2} −Ph−, or −Ph−C (CH ₃ ) ₂ −. It represents Ph-, Ph is a phenylene group, and m is an integer from 1 to 4.

It is desirable that the fiber-reinforced plastic molding material satisfies any one or more of the following.
1) The cross-linking agent (C) is soluble in the molten phenoxy resin (A) and epoxy resin (B).
2) The glass transition temperature (Tg) of the crosslinked cured product of the crosslinked or cured matrix resin composition shall be 160 ° C or higher.
3) The glass transition temperature (Tg) of the phenoxy resin (A) is 65 ° C to 150 ° C.
4) The phenoxy resin (A), the epoxy resin (B) and the cross-linking agent (C) are present in powder form, and the average particle size (D50) of the powder of the phenoxy resin (A) and the epoxy resin (B) is 10 to 150 μm. And it is 1 to 1.5 times the average particle size of the powder of the cross-linking agent (C).
5) The reinforcing fiber base material is one or more selected from the group consisting of carbon fiber, boron fiber, silicon carbide fiber, glass fiber and aramid fiber.

Another aspect of the present invention is a crosslinked cured product of the fiber-reinforced plastic molding material. It is preferable that the crosslinked cured product of the matrix resin composition has a glass transition temperature (Tg) of 160 ° C. or higher.

Further, the present invention is a method for producing a material for molding a fiber reinforced plastic, in which a phenoxy resin (A), an epoxy resin (B) and a cross-linking agent (C) are separately pulverized into powders, and then these are used. The powder was mixed to obtain a fine powder of a matrix resin composition solid at room temperature, which was adhered to the reinforcing fiber base material by powder coating so that the ratio of the matrix resin composition was in the range of 20 to 50 wt%. It is a method for producing a material for molding a fiber reinforced plastic, which is characterized by the above. It is preferable that the powder coating is a powder coating using an electrostatic field.

Further, the present invention is a method for producing a fiber-reinforced plastic molded product, which comprises heating and pressurizing the material for molding a fiber-reinforced plastic.

According to the present invention, for FRP molding, which is superior in storage stability at room temperature and has good workability without tackiness, as compared with conventional fiber reinforced plastic (FRP) molding materials using thermosetting resins. In addition to being able to obtain a material, it is possible to obtain an FRP molded product having high mechanical strength and capable of maintaining the mechanical strength in hot water for a long period of time.
Further, in the FRP molding material of the present invention, the phenoxy resin and the epoxy resin are not separately crosslinked and cured by pressure molding by a hot press, but the shaping and the matrix resin composition are integrally crosslinked and cured at the same time. Further, since the resin softening point of the cured product of the matrix resin composition can be set within −25 ° C. of Tg, it can be demolded at a high temperature of 100 ° C. or higher, and FRP production can be performed. It is possible to significantly shorten the process and greatly improve productivity.
Further, the FRP molded product obtained by heat-molding the FRP molding material of the present invention is a phenoxy resin (A) for curing the matrix resin composition even when it needs to be disposed of after being used for various purposes. Since the ester bond between the fiber and the cross-linking agent (C) is used, it is possible to separate the FRP molded product into a reinforcing fiber and a matrix resin composition by using a hydrolysis reaction and recycle it without discarding it. be.
Although the mechanism of the cross-linking reaction of the present invention is not clear, it is considered to be the following two-step reaction. That is, in the first step, the secondary hydroxyl group of the phenoxy resin reacts with the acid anhydride of the cross-linking agent, and then in the second step, the carboxylic acid group generated by the first step reaction and the epoxy of the phenoxy resin or the epoxy resin. It can be understood that the esterification reaction of the group or the secondary hydroxyl group has occurred and the excellent effect of the present invention has been exhibited. In the present invention, it is assumed that most of the cross-linking reactions of the phenoxy resin, which is the main component, are carried out by the secondary hydroxyl groups, and the ratio of the epoxy resin cured with an acid anhydride is small.

Hereinafter, the present invention will be described in detail.
The matrix resin of the material for FRP molding of the present invention is a solvent-free room temperature solid phenoxy resin composition composed of a phenoxy resin (A), an epoxy resin (B), and a cross-linking agent (C) as essential components. , (A), (B), and (C) are attached to the reinforcing fiber base material while maintaining the reactivity.

In the FRP molding material of the present invention, the phenoxy resin (A) used as an essential component in the matrix resin composition is solid at room temperature and has a melt viscosity at 200 ° C. of 1 × 10 ⁴ Pa · s or less. Things are suitable. The melt viscosity is preferably 1 × 10 ^{2 to} 6 × 10 ³ Pa · s, and more preferably 2 × 10 ^{2 to} 3 × 10 ³ Pa · s. If the melt viscosity exceeds 1 × 10 ⁴ Pa · s, the fluidity of the resin due to heat during molding is poor, and the resin does not spread sufficiently in the fiber base material, causing voids and mechanical properties of the molded product. It will drop.

The phenoxy resin (A) is a thermoplastic resin obtained by a condensation reaction between a dihydric phenol compound and epihalohydrin or a polyaddition reaction between a divalent phenol compound and a bifunctional epoxy resin, and is conventionally used in a solvent or in the absence of a solvent. It can be obtained by a known method. The average molecular weight, as the mass average molecular weight (Mw), is usually 10,000 to 200,000, preferably 20,000 to 100,000, and more preferably 30,000 to 80,000. If Mw is too low, the strength of the molded product is inferior, and if it is too high, workability and workability are likely to be inferior. In addition, Mw shows the value measured by gel permeation chromatography and converted using the standard polystyrene calibration curve.

The hydroxyl group equivalent (g / eq) of the phenoxy resin (A) is usually 50 to 1000, preferably 100 to 750, and particularly preferably 200 to 500. If the hydroxyl group equivalent is too low, the number of hydroxyl groups increases and the water absorption rate increases, which is not preferable because there is a concern that the mechanical properties may deteriorate. If the hydroxyl group equivalent is too high, the crosslink density is insufficient and the heat resistance is lowered.

The glass transition point (Tg) of the phenoxy resin (A) is preferably 65 ° C. to 150 ° C. or lower, preferably 70 ° C. to 100 ° C., and more preferably 80 ° C. to 100 ° C. If the glass transition point is lower than 65 ° C., the moldability is improved, but there are problems in the storage stability of the powder and the tackiness of the FRP molding material. If the temperature is higher than 150 ° C., the melt viscosity becomes high and the moldability and the filling property into the fiber are inferior, and as a result, press molding at a higher temperature is required. The glass transition temperature of the phenoxy resin was measured in the range of 20 to 280 ° C. using a differential scanning calorimetry device (DSC) under a heating condition of 10 ° C./min, and was calculated from the peak value of the second scan. It is a numerical value.

The phenoxy resin (A) is not particularly limited as long as it satisfies the above physical properties, but is a bisphenol A type phenoxy resin (for example, Phenototo YP-50, Phenototo YP-50S, Phenoto manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.). Tote YP-55U), bisphenol F type phenoxy resin (for example, Phenotote FX-316 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), or bisphenol A and bisphenol F copolymerized phenoxy resin (for example, YP manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) -70), special phenoxy resins other than the above (for example, YPB-43C manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., FX-293) and the like can be mentioned, and these can be used alone or in combination of two or more.

In the matrix resin composition used for the FRP molding material of the present invention, the epoxy resin (B) is blended together with the phenoxy resin (A). When the epoxy resin (B) coexists, the melt viscosity of the matrix resin composition can be reduced to enhance the impregnation property of the reinforcing fiber base material, and the strength and physical characteristics of the cured molded product can also be enhanced.
In this case, the melt viscosity of the matrix resin composition basically depends on the melt viscosity of the phenoxy resin, but is affected by the blending amount of the epoxy resin and the type of the cross-linking agent. For example, if the blending amount of the epoxy resin is large, the melt viscosity of the matrix resin composition decreases, and if the cross-linking agent is inappropriate, the melt viscosity does not decrease due to the premature reaction, so it is necessary to adjust appropriately.
The epoxy resin (B) is preferably a bifunctional or higher functional epoxy resin, and is a bisphenol A type epoxy resin (for example, Epototo YD-011, Epototo YD-7011, Epototo YD-900 manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), Bisphenol F type. Epoxy resin (for example, Epototo YDF-2001 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), diphenyl ether type epoxy resin (for example, YSLV-80DE manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), tetramethylbisphenol F type epoxy resin (for example, Nippon Steel & Sumikin Chemical Co., Ltd.) YSLV-80XY manufactured by Nippon Steel & Sumitomo Metal Corporation (for example, YSLV-120TE manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), hydroquinone type epoxy resin (for example, Epototo YDC-1312 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), phenol novolac type epoxy resin, (For example, Epototo YDPN-638 manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), Orthocresol Novolac type epoxy resin (for example, Epototo YDCN-701 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., Epototo YDCN-702, Epototo YDCN-703, Epototo YDCN-704) , Aralkyl naphthalenediol novolak type epoxy resin (for example, ESN-355 manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), triphenylmethane type epoxy resin (for example, EPPN-502H manufactured by Nippon Kayaku Co., Ltd.), etc., but these are limited. These are not used, and two or more of these may be mixed and used.

Further, in order to store the matrix resin composition as a powder, the epoxy resin (B) is more preferably solid at room temperature, has a melting point of 75 ° C. to 145 ° C., and has a melt viscosity at 160 ° C. of 1. A crystalline epoxy resin having a value of 0 Pa · s or less is preferable. If it exceeds 1.0 Pa · s, the filling property of the matrix resin composition into the reinforcing fiber base material is inferior, and the homogeneity of the obtained molded product is inferior, which is not preferable.
Since the melt viscosity of the crystalline epoxy resin is much lower than that of the solid epoxy resin, the impregnation property of the matrix resin can be improved by blending the crystalline epoxy resin. Therefore, a phenoxy resin having a high melt viscosity can be used.

The cross-linking agent (C) used in the present invention has two or more functional groups that react with the secondary hydroxyl group of the phenoxy resin and the epoxy group of the epoxy resin, and is represented by the above general formulas (1) to (3). Acid anhydride. It is understood that one acid anhydride group has two of the above functional groups because hydrolysis produces two carboxy groups.
The acid anhydride as a cross-linking agent three-dimensionally cross-links the phenoxy resin by forming an ester bond with the secondary hydroxyl group of the phenoxy resin. Therefore, unlike strong cross-linking such as curing of a thermosetting resin, the cross-linking can be broken by a hydrolysis reaction, so that there is no problem in recyclability.

（式中、Ｘは、Ｏ、−ＣＨ_２−、−Ｃ（ＣＨ_３）−、−（Ph）_ｍ−、−Ph−CH₂−Ph−、又は−Ph−C（CH₃)₂−Ph−を表し、Phはフェニレン基であり、ｍは１から4の整数である）

式中、Ｙは、−（ＣＨ_２）_ｍ−、−（Ph）_ｍ−、−Ph−CH₂−Ph−、又は−Ph−C（CH₃)₂−Ph−を表し、Phはフェニレン基であり、ｍは１から4の整数である。
なお、Ｘ、Ｙの説明において、−（Ph）_ｍ−、−Ph−CH₂−Ph−、又は−Ph−C（CH₃)₂−Ph−を構造式で示せば以下のようなものであるが、結合手は、構造式で示したｐ位に限らず、ｍ位でもｏ位であってもよく、架橋剤が溶融されたフェノキシ樹脂とエポキシ樹脂に溶解し、マトリックス樹脂組成物が透明になるのであれば、使用できる。

The acid anhydride can be used as a cross-linking agent (C) as long as it is solid at room temperature and has low sublimation properties, but in the present invention, heat resistance is imparted to the molded product and the cross-linking density is increased. From this point of view, it is an aromatic tetracarboxylic acid dianhydride, and is at least one aromatic tetracarboxylic acid dianhydride represented by the general formulas (1) to (3).

(In the formula, X is O, -CH _2- , -C (CH ₃ )-,-(Ph) _{m- , -Ph-CH 2-} Ph-, or -Ph-C (CH ₃ ) ₂ -Ph. Represents −, Ph is a phenylene group, and m is an integer from 1 to 4)

In the formula, Y represents − (CH ₂ ) _m −, − (Ph) _m −, _{−Ph−CH 2} −Ph−, or −Ph−C (CH ₃ ) ₂ −Ph−, where Ph is a phenylene group. And m is an integer from 1 to 4.
In the explanation of X and Y, if − (Ph) _m −, _{−Ph−CH 2} −Ph−, or −Ph−C (CH ₃ ) ₂ −Ph− is expressed by the structural formula, it is as follows. However, the bond is not limited to the p-position shown in the structural formula, but may be at the m-position or the o-position. The cross-linking agent is dissolved in the melted phenoxy resin and epoxy resin, and the matrix resin composition is transparent. If it becomes, it can be used.

The aromatic tetracarboxylic acid dianhydrides represented by the general formulas (1) to (3) are compatible with the phenoxy resin and the epoxy resin, which are the main components of the matrix resin composition, until the cross-linking agent itself is melted by heat. Since many of them are difficult to do, the melt viscosity does not increase due to the crosslinking reaction starting from a low temperature. Therefore, the cross-linking reaction is started after the matrix resin composition is melted during the molding process and becomes sufficiently low in viscosity. Therefore, the cross-linking reaction is good in addition to the good impregnation property of the matrix resin into the reinforcing fiber base material. Since it is carried out promptly and without excess or deficiency, it does not remain as a foreign substance in the matrix resin in an unreacted state, and the mechanical strength of the molded product starting from the residual cross-linking agent (C) and the mechanical strength in hot water are reduced. Does not cause any problems.
Regarding the compatibility of the cross-linking agent (C) with the phenoxy resin (A) and the epoxy resin (B), the matrix resin composition which is a mixture of these is melted at 200 ° C., kneaded, and reacted and cured after cooling. This was done by evaluating the transparency by visually observing the object.

Examples of such aromatic tetracarboxylic dianhydrides include 4,4'-oxydiphthalic anhydride, 4,5'-oxydiphthalic anhydride, and 5,5'-methylenebis (isobenzofuran-1,3-dione). , 5,5'-Isopropylidenebis (isobenzofuran-1,3-dione), ethylene glycol bisanhydrotrimeritate, bis (1,3-dioxoisobenzofuran-5-carboxylic acid) tetramethylene, 4, 5'-[1,4-phenylene bis (oxy)] bis (isobenzofuran-1,3-dione), 4,4'-(m-phenylene bisoxy) bis (isobenzofuran-1,3-dione), 5,5'-[1,3-phenylenebis (oxy)] bis (isobenzofuran-1,3-dione), 3,3'-(p-phenylenedioxy) diphthalic anhydride, 5,5- [1,2-Phenylenebis (oxy)] bis (isobenzofuran-1,3-dione), 4,4'-[2,1-phenylenebis (oxy)] bis (isobenzofuran-1,3-dione) 4,4'-(p-phenylenedioxy) diphthalic anhydride, 5,5'-[biphenyl-4,4'-diylbis (oxy)] bis (isobenzofuran-1,3-dione), 5 , 5'-[biphenyl-2,2'-diylbis (oxy)] bis (isobenzofuran-1,3-dione), bisphenol A, diphthalic anhydride, 2,2'-di (4-trimelitoyloxy) ) Biphenyl dianhydride, 2,2'-bis (4-hydroxyphenyl) propandibenzoate-3,3', 4,4'-tetracarboxylic acid dianhydride, bis (1,3-dioxoisobenzofuran-) 5-carboxylic acid) isopropylidenebis (4,1-phenylene), 3,3'-diphenyl-4,4'-biphenol-bis (trimeritateanhydride), etc., among which 4,4 At least one aromatic tetracarboxylic dianhydride selected from ′ -oxydiphthalic anhydride, ethylene glycol bisanhydrotrimeritate, and 4,4 ′-(1-methylethylidene) diphthalic anhydride is a cross-linking agent ( Most preferable as C).

The reaction of the phenoxy resin (A), the epoxy resin (B) and the cross-linking agent (C) is an esterification reaction between the secondary hydroxyl group in the phenoxy resin (A) and the acid anhydride group of the cross-linking agent (C), and further. It is crosslinked and cured by the reaction between the carboxyl group generated by this esterification reaction and the epoxy group of the epoxy resin (B). A phenoxy resin crosslinked product can be obtained by reacting the phenoxy resin (A) with the cross-linking agent (C), but the coexistence of the epoxy resin (B) reduces the melt viscosity of the matrix resin composition to form a reinforcing fiber base material. It is a material for FRP molding suitable for obtaining an excellent FRP molded product such as promotion of a cross-linking reaction, improvement of a cross-linking density, and improvement of mechanical strength, in addition to being able to enhance the impregnation property of the resin. In the present invention, although the epoxy resin (B) coexists, the main component is the phenoxy resin (A) which is a thermoplastic resin, and the secondary hydroxyl group and the acid anhydride of the cross-linking agent (C) are used as the main components. It is considered that the esterification reaction with the group is prioritized. That is, since the reaction between the acid anhydride used as the cross-linking agent (C) and the epoxy resin (B) takes time, the cross-linking reaction by the secondary hydroxyl group of the phenoxy resin (A) occurs first, and the cross-linking agent (C) ) Is deactivated, it is considered that the reactivity with the epoxy resin (B) is greatly reduced. Therefore, the FRP molding material of the present invention is different from the usual FRP molding material containing an epoxy resin which is a thermosetting resin as a main component, and maintains the moldability and the physical properties of the FRP molded product even after long-term storage at room temperature. It has excellent storage stability.

Further, the curing accelerator (D) can also be added to the phenoxy resin composition of the present invention. The curing accelerator (D) is not particularly limited as long as it is solid at room temperature and does not have sublimation properties. For example, a tertiary amine such as triethylenediamine, 2-methylimidazole, or 2-phenylimidazole is used. , 2-Phenyl-4-methylimidazole and other imidazoles, triphenylphosphine and other organic phosphines, tetraphenylphosphonium tetraphenylborate and other tetraphenylborone salts, and the like. These curing accelerators (D) may be used alone or in combination of two or more. From the viewpoint of the production process of the present invention, it is preferable to use a curing accelerator which is a latent catalyst for imidazoles solid at room temperature having a catalytic activity temperature of 130 ° C. or higher.

Further, the FRP molding material of the present invention includes other thermoplastic resin powders such as polyvinyl chloride resin, as long as the good adhesion to the reinforcing fiber base material and the physical properties of the FRP molded product after molding are not impaired. Powders such as polyvinyl chloride resin, natural rubber, and synthetic rubber, and other additives such as various inorganic fillers, extender pigments, colorants, antioxidants, and ultraviolet antioxidants can also be blended.

The matrix resin composition of the material for FRP molding of the present invention contains essential components such as phenoxy resin (A), epoxy resin (B) and cross-linking agent (C), and if necessary, a curing accelerator (D) and a moisture-resistant pigment. , Colorants, and other additives are crushed to a predetermined size, mixed at a predetermined blending ratio, and the fine powder of this matrix resin composition is adhered to the reinforcing fiber base material in the powder state. can get.

In the matrix composition of the present invention, the epoxy resin (B) is blended in an amount of 5 to 85 parts by weight with respect to 100 parts by weight of the phenoxy resin (A). It is preferably 9 to 83 parts by weight, more preferably 10 to 70 parts by weight. If the blending amount of the epoxy resin (B) exceeds 85 parts by weight, it takes time to cure the epoxy resin, so that it becomes difficult to obtain the strength required for demolding in a short time, and the recyclability of FRP is lowered. Further, if the blending amount of the epoxy resin (B) is less than 5 parts by weight, the effect of blending the epoxy resin cannot be obtained, and the cured product of the matrix resin composition is less likely to express Tg at 160 ° C. or higher.

The matrix resin composition is solid at room temperature, and its melt viscosity is 3000 Pa · s or less in any of the temperature ranges of 160 to 220 ° C. The temperature range of 160 to 220 ° C. is a temperature range in which normal hot press molding is performed. It is preferably 2900 Pa · s or less, more preferably 2800 Pa · s. If the melt viscosity exceeds 3000 Pa · s, the reinforcing fiber base material is insufficiently impregnated with the matrix resin composition during molding by hot pressing, causing defects such as internal voids and deteriorating the mechanical properties of the FRP.
The melt viscosity sharply increases when the phenoxy resin (A) and the epoxy resin (B) in the matrix resin composition react with the cross-linking agent (C). Therefore, if the reaction between the phenoxy resin (A) and the epoxy resin (B) is started before the epoxy resin (B) is sufficiently melted, the melt viscosity does not become 3000 Pa · s or less, and the reinforcing fiber base material is used. Poor impregnation of the matrix resin in the above causes voids in the molded product. Therefore, the melting point of the cross-linking agent (C) is preferably in the range of 150 ° C. or higher, preferably the molding temperature (160 to 220 ° C.).

The blending amount of the cross-linking agent (C) is usually in the range of 0.6 to 1.3 mol of the acid anhydride group with respect to 1 mol of the secondary hydroxyl group of the phenoxy resin (A), and is preferably 0.9. The amount is in the range of ~ 1.3 mol, more preferably in the range of 0.9 to 1.1 mol. If the amount of the acid anhydride group is too small, the acid anhydride group reactive with respect to the secondary hydroxyl group of the phenoxy resin (A) is insufficient, so that the crosslink density is low and the rigidity is inferior. The acid anhydride becomes excessive with respect to the secondary hydroxyl group of the above, and the unreacted acid anhydride adversely affects the curing characteristics and the cross-linking density. In addition to directly cross-linking the phenoxy resin with the acid anhydride group (COOH) of the cross-linking agent, it is considered that two types of cross-linking of the phenoxy resin via the epoxy resin coexist, and the acid of the cross-linking agent It is assumed that the anhydride group and the carboxyl group in which the acid anhydride group is opened are consumed by the secondary hydroxyl group of the phenoxy resin and the epoxy group of the epoxy resin, and there is almost no carboxyl group remaining in the cured product.

When a curing accelerator (D) is used in addition to the essential components (A) to (C), the blending amount of (D) is the total of the phenoxy resin (A), the epoxy resin (B) and the cross-linking agent (C). The amount is 0.1 to 5 parts by weight with respect to 100 parts by weight. Other additives are appropriately adjusted and added so as not to adhere the matrix resin composition powder to the base material or impair the characteristics of the molded product.

Further, it is desirable that a flame retardant is added to the FRP molding material of the present invention. The flame retardant is not particularly limited as long as it is solid at room temperature and does not sublimate, but the use of a non-halogen flame retardant is preferable from the viewpoint of the environment and health, and for example, an inorganic flame retardant such as calcium hydroxide or , Organic and inorganic phosphorus flame retardants such as ammonium phosphates and phosphoric acid ester compounds, nitrogen-containing flame retardants such as triazine compounds, and bromine-containing flame retardants such as brominated phenoxy resin. Among them, the brominated phenoxy resin and the phosphorus-containing phenoxy resin can be preferably used because they can be used as a flame retardant and a matrix resin. The amount of the flame retardant to be blended is appropriately selected depending on the type of the flame retardant and the desired degree of flame retardancy, but is generally in the range of 0.01 to 10 parts by weight with respect to 100 parts by weight of the matrix resin composition. It is preferable to blend the matrix resin composition to the extent that it does not impair the adhesiveness of the matrix resin composition and the physical properties of the FRP.

In the method for producing a material for FRP molding of the present invention, each component constituting the matrix resin composition is made into a fine powder and adheres to the reinforcing fiber base material. Therefore, each component is pulverized into a fine powder. The pulverization is preferably performed by a pulverizer / mixer such as a low-temperature drying pulverizer (Sentry Dry Mill), but the pulverization is not limited thereto. Further, at the time of crushing, each component may be crushed and then mixed, or each component may be mixed in advance and then crushed, but the former is preferable. In this case, it is advisable to set the pulverization conditions so that each fine powder has an average particle size described later. The powder thus obtained has an average particle size of 10 to 100 μm, preferably 40 to 80 μm, and more preferably 40 to 50 μm. When the average particle size exceeds 100 μm, the energy when the resin collides with the fibers increases in the adhesion to the reinforcing fiber base material by powder coating in an electrostatic field, and the adhesion rate to the reinforcing fiber base material decreases. It ends up. If it is less than 10 μm, the particles are scattered by the accompanying airflow and the adhesion efficiency is lowered, and the fine powder resin floating in the atmosphere may cause deterioration of the working environment. At this time, it is preferable that the average particle size of the phenoxy resin (A) and epoxy resin (B) powder is 1 to 1.5 times the average particle size of the cross-linking agent (C). By making the particle size of the cross-linking agent (C) powder smaller than that of the phenoxy resin (A) and epoxy resin (B) powders, the cross-linking agent is adhered to the inside of the reinforcing fiber base material, and (A). ), The cross-linking agent (C) is evenly present around the particles of the component (B), so that the cross-linking reaction can surely proceed.

The powder of the matrix resin composition is adhered to the reinforcing fiber base material by the powder coating method to obtain the FRP molding material of the present invention. The powder coating method includes a fluidized coating method using a fluidized bed and an electrostatic coating method using an electrostatic field. In the present invention, either method can be used, but adhesion to the reinforcing fiber base material can be used. From the viewpoint of uniformity, an electrostatic coating method using an electrostatic field is preferable.

The amount of the matrix resin composition powder adhered to the reinforcing fiber base material is coated so that the resin ratio (RC) is 20 to 50 wt%, but is preferably 25% to 40%, more preferably 25% to 40%. It is 25% to 30%. If the resin adhesion rate exceeds 50%, the mechanical properties such as the tensile and bending elastic modulus of the FRP deteriorate, and if it is less than 10%, the amount of resin adhered is extremely small, so that the matrix resin is impregnated inside the substrate. It becomes insufficient, and both thermal and mechanical properties become low.

The powder of the matrix resin composition coated with powder is fixed to the reinforcing fiber base material by heating and melting, but it is applied to cold coating in which the powder is applied and then heat-sealed, and to preheated reinforcing fibers. Either hot coating, in which powder is applied or fused, may be used. By melting the matrix resin on the surface of the reinforcing fiber base material by this heat melting, the adhesion to the base material is enhanced and the coated resin powder is prevented from falling off. However, in the obtained FRP material, the matrix resin is concentrated on the surface of the reinforcing fiber base material, and does not reach the inside of the reinforcing fiber base material as in the molded product after heat and pressure molding. The heating time after powder coating is not particularly limited as long as the matrix resin composition of the FRP molding material can maintain fluidity and reactivity, but 1 to 2 minutes is suitable. That is, by performing the heat treatment in a much shorter time than at the time of molding, the phenoxy resin, the epoxy resin, etc. are fixed to the reinforcing fiber base material by heat fusion without reacting the cross-linking agent and the resin, and powder falling is prevented. do. The melting temperature is 150-240 ° C, preferably 160-220 ° C, more preferably 180-200 ° C. If the melting temperature exceeds the upper limit, the curing reaction may proceed, and if it falls below the lower limit, heat fusion becomes insufficient, and powder falling or falling off of the matrix resin occurs when handling the FRP molding material. do.

Carbon fiber, glass fiber, aramid fiber, boron fiber, alumina fiber, mineral fiber, silicon carbide fiber, etc. can be used as the reinforcing fiber base material, but it is necessary to have conductivity in order to use the electrostatic coating method. Therefore, carbon fiber is preferable. The form of the reinforcing fiber base material is not particularly limited, and is, for example, a unidirectional material, a cloth such as plain weave or twill weave, a three-dimensional cloth, a chopped strand mat, a tow made of thousands or more filaments, or a non-woven fabric. Etc. can be used. These reinforcing fiber base materials can be used alone or in combination of two or more.

The FRP molded product of the present invention produced in this manner can be easily produced by using it alone or by laminating it, heating and pressurizing it. Further, when laminating, a metal foil such as aluminum or stainless steel can be laminated between layers or the outermost layer. The FRP molding material of the present invention can be shaped and crosslinked and cured of the matrix resin at the same time by pressure molding by a hot press.
For molding using FRP molding materials, as long as it is heat and pressure molding, various molding methods such as autoclave molding and hot press molding using a mold are appropriately selected according to the size and shape of the target molded product. Can be carried out. The molding temperature is 150 to 240 ° C., preferably 160 ° C. to 220 ° C., more preferably 180 ° C. to 200 ° C. If the molding temperature exceeds the upper limit temperature in the above range, excessive heat is applied and the resin may be decomposed. If the molding temperature is lower than the lower limit temperature, the melt viscosity of the matrix resin composition is high, so that the fiber Adhesion to the impregnation property deteriorates. The molding time is usually 30 to 60 minutes, but even for a short time of about 10 minutes, the molding time is different from that of the cross-linking agent (C) using the secondary hydroxyl group of the phenoxy resin (A) as the main component. By the reaction, the strength for demolding can be obtained. However, in order to complete the curing reaction of the epoxy resin (B), it is preferable to post-cure at 200 to 250 ° C. for about 30 to 60 minutes, for example.

In the FRP molding material of the present invention, the heat resistance of the matrix resin composition is greatly increased as compared with that before molding by the cross-linking reaction using the secondary hydroxyl group of the phenoxy resin, and a molded product having a Tg of 160 ° C. or higher can be obtained. Since the softening point of the cured product of the matrix resin composition is within approximately -25 ° C. from Tg, for example, in hot press molding using a mold, the demolding temperature of the molded product from the mold is the matrix resin composition. It is possible if it is in the range of −30 ° C. or lower from the Tg of the cured product, preferably −35 ° C. or lower, more preferably Tg to −40 ° C. or lower from the Tg of the cured product. If the demolding temperature exceeds the upper limit temperature in the above range, the shaping cannot be maintained, and if the demolding temperature is too low, the time required for cooling becomes long, so that the tact time becomes long and the productivity decreases. ..
The softening point indicates the temperature of the inflection point at which the storage elastic modulus (E') measured by DMA of the cured matrix resin is attenuated.

The cured product of the fiber-reinforced plastic molding material of the present invention is obtained by heating and curing the FRP molding material, and the above-mentioned cross-linking is developed. This cured product contains a cured product of the matrix resin in the material for molding the upper fiber reinforced plastic and the reinforcing fiber base material, and these are firmly bonded to each other to give properties such as predetermined strength. The glass transition temperature of the crosslinked cured product of this matrix resin composition is preferably 160 ° C. or higher.

The method for producing a fiber-reinforced plastic molded product of the present invention is to heat and pressurize the material for molding fiber-reinforced plastic to cure and mold the material.

Examples will be shown below and the present invention will be described in more detail, but the present invention is not limited to the description of these examples.

The materials used in the examples and comparative examples are as follows.

（酸無水物当量：２６０、融点：１８４℃、ＳＡＢＩＣ社製ＢｉｓＤＡ）
（Ｃ−４）：４，４’−ビフタル酸無水物
（酸無水物当量：１４７、融点：２２９℃、ＢＰＤＡ）
（Ｃ−５）：３，３’，４，４’−ベンゾフェノンテトラカルボン酸二無水物
（酸無水物当量：１６１、融点：２１８℃、ＢＴＤＡ）
（Ｃ−６）：３，３’，４，４’‐ジフェニルスルホンテトラカルボン酸二無水物
（酸無水物当量：１７９、融点：≧２８７℃、ＤＳＤＡ）Phenoxy resin (A)
(A-1): Phenototo YP-50S (Bisphenol A type manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., Mw = 40,000, hydroxyl group equivalent = 284), melt viscosity at 200 ° C. = 3,000 Pa · s, glass transition temperature (A-1) Tg) = 83 ° C
Epoxy resin (B)
(B-1): YSLV-80XY (Tetramethylbisphenol F type manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent = 192, melting point = 72 ° C.)
Crosslinking agent (C)
(C-1): Ethylene glycol bisuanhydrotrimeritate
(Acid anhydride equivalent: 207, melting point: 160 ° C, TEMG)
(C-2): 4,4'-oxydiphthalic anhydride
(Acid anhydride equivalent: 153, melting point: 225 ° C, OPDA)
(C-3): Bisphenol A, diphthalic anhydride

(Acid anhydride equivalent: 260, melting point: 184 ° C, BisDA manufactured by SABIC)
(C-4): 4,4'-biphthalic anhydride
(Acid anhydride equivalent: 147, melting point: 229 ° C, BPDA)
(C-5): 3,3', 4,4'-benzophenone tetracarboxylic dianhydride
(Acid anhydride equivalent: 161, melting point: 218 ° C, BTDA)
(C-6): 3,3', 4,4'-diphenylsulfonetetracarboxylic dianhydride
(Acid anhydride equivalent: 179, melting point: ≧ 287 ° C, DSDA)

The testing and measuring methods for various physical properties are as follows.

Melt Viscosity The melt viscosity of the matrix resin composition, etc. is determined by sandwiching a sample size of 4.3 cm3 between parallel plates using a rheometer (manufactured by Antonio Par) and raising the temperature at 50 ° C./min while measuring frequency: 1 Hz and load strain. : The melt viscosity at 160 ° C. was measured under the condition of 5%.

Average particle size The average particle size of the matrix resin composition powder, etc. is measured by volume-based average particle size (D50) using a laser diffraction / scattering type particle size distribution measuring device (Microtrack MT3300EX, manufactured by Nikkiso Co., Ltd.). rice field.

Compatibility (transparency) between the resins (A) and (B) and the cross-linking agent (C)
A matrix resin composition in which a cross-linking agent (C) is mixed with a phenoxy resin (A) and an epoxy resin (B) is dissolved at 200 ° C. and kneaded, and the transparency is evaluated by visual observation of the reaction-cured product after cooling. I went there.

Tackiness of Preform Sheet The surface of the obtained FRP molding material was touched with a finger, and those without tackiness were accepted and marked with ◯ in Table 1.

Resin ratio (RC:%)
It was calculated from the weight of the carbon fiber cloth (W1) before the matrix resin composition was attached and the weight of the FRP molding material (W2) after the resin composition was attached using the following formula.
Resin ratio (RC:%) = (W2-W1) / W2 × 100
W1: Weight of reinforcing fiber before attachment of matrix resin composition W2: Weight of FRP molding material after attachment of matrix resin composition

Glass transition temperature (Tg), resin softening temperature A test piece having a thickness of 2 mm, a width of 10 mm, and a length of 10 mm was measured at 5 ° C./min using a dynamic viscoelasticity measuring device (DMA, DMA 7e manufactured by Perkin Elmer). The temperature was measured in the temperature range of 25 to 250 ° C., and the maximum peak of tan δ obtained was taken as the glass transition point.
The resin softening temperature was set to the temperature of the inflection point at which the storage elastic modulus (E') measured by DMA was attenuated in the same test piece of the molded cured product. Shows the temperature at which mold can be removed after molding and curing.

Mechanical properties 13 sheets of FRP molding material are stacked on a Teflon (registered trademark) sheet and pressed at 5 MPa for 10 minutes with a press machine heated to 200 ° C. to prepare an FRP laminated board, and then aftercured in an oven for 1 hour. The mechanical properties (bending elastic modulus, bending strength) of the obtained FRP laminated plate were measured based on the bending test method of JIS K 7074: 1988 fiber reinforced plastic.

13 sheets of resin-impregnated FRP molding material were stacked on a Teflon sheet and pressed at 5 MPa for 5 minutes with a press machine heated to 200 ° C. to prepare a laminated board, and then aftercured in an oven for 1 hour. Several pieces of 10 mm square were cut out using a diamond cutter. The cut surface of the cut pieces was polished with # 1000 or more water-resistant abrasive paper, and then observed with an optical microscope to confirm the presence or absence of voids.

Stability of FRP molding materials stored at room temperature 13 sheets of FRP molding materials stored in a room at room temperature for 3 months were stacked on a Teflon sheet and pressed at 5 MPa for 5 minutes with a press machine heated to 200 ° C. After that, after-cure was performed in an oven for 1 hour to evaluate the thermal and mechanical properties. A comparison was made with the laminated board manufactured three months ago, and if the error in the physical properties was within the range of ± 10%, it was accepted and marked with ◯ in Table 1.

Long-term heat resistance test of CFRP A test piece prepared in the same manner as the test piece for measuring mechanical properties is held for 500 hours in a temperature environment of 100 ° C., and then based on the bending test method of JIS K 7074: 1988 fiber reinforced plastic. The mechanical strength was measured.

Example 1
(A-1) as the phenoxy resin (A), (B-1) as the epoxy resin (B), and (C-1) as the cross-linking agent (C) are crushed and classified to have an average particle size D50 of 80 μm (A). , B, C have almost the same average particle size), dry-blended at the ratio (part by weight) shown in Table 1, and from carbon fiber (STANDARD Modulus type HTS40 3K, manufactured by Toho Tenax Co., Ltd.). The plain-woven reinforced fiber base material which had been subjected to the fiber-spreading treatment was powder-coated in an electrostatic field under the conditions of a charge of 70 kV and a sprayed air pressure of 0.32 MPa. Then, the resin was heat-melted by heating and melting at 170 ° C. for 1 minute in an oven to obtain a material for FRP molding. The resin ratio (RC) of the obtained FRP molding material was 27%.
Various physical properties of the FRP molding material and the FRP cured product thus obtained were measured. These results are shown in Table 1.

Examples 2 and 3 and Comparative Examples 1 to 3
Except for using (C-2), (C-3), (C-4), (C-5), and (C-6) instead of (C-1) as the cross-linking agent (C), the same as in Example 1. Similarly, a material for FRP molding and further an FRP laminated board were obtained, and various physical properties were evaluated. The results are also shown in Table 1.
The flexural modulus, bending strength, and long-term heat resistance of Comparative Example 3 could not be measured because the matrix resin was brittle.

From the results obtained in Table 1, from the FRP molding material in which the fine powder of the matrix resin composition using C-1, C-2, and C-3 as the cross-linking agent (C) was adhered to the reinforcing fiber base material. The obtained CFRP exhibits excellent heat resistance of Tg of 160 ° C. or higher, and has a low melt viscosity of the matrix resin composition, so that it has good impregnation property into the reinforcing fiber base material and exhibits high mechanical strength. Further, since the cross-linking agent has good compatibility with the phenoxy resin and the epoxy resin, the reactivity is good, and since it does not remain as a solid substance, the machine is exposed to hot conditions of 100 ° C. for a long period of time. The decrease in strength is small. As described above, the FRP molding material of this example is very excellent as an FRP molding material because it can obtain an FRP molded product having high heat resistance and mechanical properties at room temperature and hot.

Industrial application fields

The fiber-reinforced plastic molding material of the present invention is a fiber-reinforced plastic (FRP) material that can be used as a body or body of transportation equipment such as automobiles and aviation equipment, from housings of electronic devices such as notebook PCs and tablets, to industrial robots and the like. It can be used in a wide range of fields such as arms, reinforcing materials for building structures, and sports and leisure fields such as fishing rods and road bike bodies.

Claims (10)

A material for molding a fiber-reinforced plastic composed of a matrix resin composition and a reinforcing fiber base material, wherein the matrix resin composition contains a phenoxy resin (A), an epoxy resin (B) and a cross-linking agent (C) as essential components, and phenoxy. The epoxy resin (B) is contained in an amount of 9 to 85 parts by weight based on 100 parts by weight of the resin (A), and the cross-linking agent (C) is at least one tetracarboxylic acid represented by the following general formulas (1) to (3). It is a dianhydride and is contained in a range of 0.6 to 1.3 mol of the acid anhydride group of the cross-linking agent (C) with respect to 1 mol of the secondary hydroxyl group of the phenoxy resin (A). in the composition solid state at room temperature, 160 ° C. to 220 Ri der melt viscosity of 3000 Pa · s or less at any temperature range of ° C., crosslinked or glass transition temperature of the cured cross-linked cured product of the matrix resin composition (Tg) Is 160 ° C. or higher, the fiber-reinforced plastic molding material contains 20 to 50 wt% of the matrix resin composition, and the fine powder of the matrix resin composition adheres to the surface of the reinforcing fiber base material. A material for molding fiber-reinforced plastics.

In the formula, X represents O, −CH ₂₋ or −C (CH ₃ ) −.

In the general formulas (2) and (3), Y is − (CH ₂ ) _m −, − (Ph) _m −, _{−Ph−CH 2} −Ph−, or −Ph−C (CH ₃ ) ₂ −. It represents Ph-, Ph is a phenylene group, and m is an integer from 1 to 4. The fiber-reinforced plastic molding material according to claim 1, wherein the cross-linking agent (C) is soluble in the molten phenoxy resin (A) and epoxy resin (B). The fiber-reinforced plastic molding material according to claim 1 or 2 , wherein the glass transition temperature (Tg) of the phenoxy resin (A) is 65 ° C. to 150 ° C. The phenoxy resin (A), the epoxy resin (B) and the cross-linking agent (C) are present in powder form, and the average particle size (D50) of the powder of the phenoxy resin (A) and the epoxy resin (B) is 10 to 150 μm. The material for molding a fiber-reinforced plastic according to any one of claims 1 to 3 , which is 1 to 1.5 times the average particle size of the powder of the cross-linking agent (C). The fiber according to any one of claims 1 to 4 , wherein the reinforcing fiber base material is one or more selected from the group consisting of carbon fiber, boron fiber, silicon carbide fiber, glass fiber and aramid fiber. Material for reinforced plastic molding. The cured product of the fiber-reinforced plastic molding material according to any one of claims 1 to 5. The cured product according to claim 6 , wherein the crosslinked cured product of the matrix resin composition has a glass transition temperature (Tg) of 160 ° C. or higher. The method for producing a fiber-reinforced plastic molding material according to any one of claims 1 to 5 , wherein the phenoxy resin (A), the epoxy resin (B), and the cross-linking agent (C) are separately pulverized. After making powder, these powders are mixed to obtain a fine powder of a matrix resin composition that is solid at room temperature, and this is reinforced by powder coating so that the ratio of the matrix resin composition is in the range of 20 to 50 wt%. A method for producing a material for molding a fiber-reinforced plastic, which is characterized by being adhered to a base material. The method for producing a fiber-reinforced plastic molding material according to claim 8 , wherein the powder coating is powder coating using an electrostatic field. A method for producing a fiber-reinforced plastic molded product, which comprises heating and pressurizing the fiber-reinforced plastic molding material according to any one of claims 1 to 5.