JP2015085658A - Resin sheet and manufacturing method of fiber-reinforced composite molded body using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin sheet favorable for forming a surface protective layer of an FRP molded body, allowing the FRP molded body to have a mat surface, without a need of cleaning or polishing, or without applying a coating.SOLUTION: A resin sheet includes: a release sheet; and a resin layer formed on one surface of the release sheet. The one surface of the release sheet has a mat surface with 20% or less of a surface gloss value (at an incident angle of 60°) measured by a specular glossiness measurement method according to JIS Z 8741. The resin layer at least includes an epoxy resin, a curing agent and a curing catalyst. The resin layer is disposed on the mat surface of the first release sheet.

Description

  The present invention relates to a resin sheet suitable for forming a surface protective layer such as a fiber reinforced plastic, and a fiber reinforced plastic using the resin sheet when the fiber reinforced plastic is produced from a prepreg or after the fiber reinforced plastic is produced. The present invention relates to a method for producing a fiber-reinforced composite molded body in which a resin layer is provided on a plastic surface.

In recent years, from the viewpoint of CO ₂ reduction, in the field of transportation vehicles such as automobiles, hybrid vehicles, electric vehicles, and the like have begun to spread in place of conventional vehicle bodies that employ internal combustion engines. It has become an important issue. In response to such problems, the use of aluminum or fiber reinforced plastic (hereinafter also referred to as FRP) instead of conventional steel is being promoted.

  FRP, which is made by mixing resin with carbon fiber or other reinforcing fiber material, is lightweight and strong, so it can be used in a wide range of fields such as aircraft, automobiles, ships, and construction industries. Has been. Such FRP is made by impregnating a woven fabric made of fiber bundles with resin and curing it, or by laminating face materials made of fiber bundles arranged in the same direction so that their fiber arrangement directions are different from each other. A resin impregnated and cured is known.

  The FRP molded body as described above is formed into a desired shape by overlaying a sheet in which a reinforcing fiber material such as carbon fiber is mixed with an epoxy resin called a prepreg, and heating and pressing in a molding die. In general, the prepreg is cured and molded. Also, in order to make it easy to take out the cured prepreg from the molding die, usually, a mold release agent such as silicone is applied to the inside of the molding die to mold the prepreg. The mold release agent may remain.

  By the way, since FRP uses a general-purpose epoxy resin or the like as a curable resin, when it is used for a vehicle body or the like, in order to prevent discoloration or strength reduction due to ultraviolet rays or wind and rain, normally, FRP In order to protect the surface of the molded body, it is necessary to perform coating by painting or the like. However, as described above, since the release agent may remain on the surface of the FRP molded body, when performing coating, after first cleaning the FRP molded body, polishing the surface, After applying the primer, etc., it was necessary to coat with a paint containing an ultraviolet absorber or the like.

  In response to the above problem, Japanese Patent Application Laid-Open No. 2006-044264 (Patent Document 1) proposes decorating the surface of the molded body by providing a film including a thermoplastic resin layer on the surface of the FRP molded body. Has been. According to this method, it is considered possible to improve the weather resistance of the FRP molded product without going through the steps as described above.

  In addition, the FRP molded body obtained by curing the prepreg may have a cross stitch on the surface, or a depression hole may be formed at the intersection of the warp and weft on the surface of the face material. In order to improve the appearance design, it is necessary to apply a paint to the surface of the molded body to fill the recessed holes, or to adhere the film as described above to the surface of the molded body.

  On the other hand, the FRP molded body whose surface is improved in smoothness by applying a paint to the surface is prone to scratches depending on the intended use. Therefore, by adding fine particles such as silica to the paint, The surface is decorated with a matte tone. However, in order to make the surface matt, it is necessary to perform a process of applying a paint to the surface of the FRP molded body and drying it a plurality of times, which causes a problem that the process is complicated.

JP 2006-044264 A

  As a result of intensive studies, the present inventors have developed a resin sheet provided with a thermosetting resin layer containing a specific component on the surface of a release sheet (separator) having a predetermined surface roughness on the surface of the FRP. The matte protective layer made of thermosetting resin can be formed on the surface of the FRP by placing it and then releasing the release sheet after curing the resin sheet. As a result, cleaning and polishing are required. The present inventors have found that an FRP molded body having a matte surface can be obtained without coating and coating. The present invention is based on this finding.

  Accordingly, an object of the present invention is to form a surface protection layer of an FRP molded body that can obtain an FRP molded body having a mat-like surface without the need for cleaning or polishing, and without performing coating. It is to provide a suitable resin sheet.

  Another object of the present invention is to provide a fiber reinforced composite molded body in which a protective layer is integrally formed on the surface of an FRP molded body using a resin sheet.

The resin sheet according to the present invention is a resin sheet comprising a release sheet and a resin layer provided on one surface of the release sheet,
One surface of the release sheet is provided with a matte surface having a surface gloss value (60 ° incidence) of 20% or less measured by a specular gloss measurement method according to JIS Z 8741.
The resin layer comprises at least an epoxy resin, a curing agent, and a curing catalyst;
The resin layer is provided on the mat surface of the release sheet.

  According to an aspect of the present invention, the curing agent may be at least one selected from the group consisting of dicyandiamide, a latent amine compound, and a thiol compound.

  According to an aspect of the present invention, the curing catalyst may be at least one selected from the group consisting of aliphatic amines, aromatic amines, aliphatic dimethylureas, aromatic dimethylureas, and imidazoles. Good.

  According to an aspect of the present invention, the epoxy resin may be a bisphenol type epoxy resin.

  Moreover, according to the aspect of the present invention, the bisphenol-type epoxy resin includes two kinds of bisphenol-type epoxy resins that are liquid at room temperature and bisphenol-type epoxy resins that are solid at room temperature with a glass transition temperature in the range of 50 to 170 ° C. It may be made of a bisphenol type epoxy resin.

  According to the aspect of the present invention, the resin layer may further include an acrylic resin.

A method for producing a fiber-reinforced composite molded article according to another aspect of the present invention includes:
A prepreg formed by impregnating a reinforcing fiber with an uncured or semi-cured thermosetting resin or thermoplastic resin is bonded to the resin sheet so that the resin layer side of the resin sheet faces, to form a laminate,
The laminate is heated and molded under pressure to cure the prepreg and resin layer,
Peeling the release sheet from the resin sheet to form a fiber reinforced composite molded body,
It is characterized by comprising.

Moreover, the method for producing a fiber-reinforced composite molded body according to another aspect of the present invention includes:
A method for producing a fiber-reinforced composite molded body,
A prepreg formed by impregnating a reinforcing fiber with an uncured or semi-cured thermosetting resin or thermoplastic resin is heated under pressure to form a fiber reinforced plastic,
The resin sheet is bonded to the surface of the fiber reinforced plastic so that the resin layer side of the resin sheet is opposed to the laminate,
Curing the resin layer of the laminate,
Peeling the release sheet from the resin sheet to form a fiber reinforced composite molded body,
It is characterized by comprising.

Furthermore, the method for producing a fiber-reinforced composite molded body according to another aspect of the present invention includes:
The resin sheet is bonded to a sheet made of reinforcing fibers so that the resin layer side of the resin sheet is opposed to the laminate,
The laminated body is placed in a mold, an uncured thermosetting resin or thermoplastic resin is injected into the mold under pressure, and reinforcing fibers are impregnated with the thermosetting resin or thermoplastic resin. Let
Curing the thermosetting resin or thermoplastic resin,
Peeling the release sheet from the resin sheet to form a fiber reinforced composite molded body,
It is characterized by comprising.

  According to the present invention, it is suitable for forming a surface protective layer of an FRP molded body, which does not require cleaning, polishing, etc., and can obtain an FRP molded body having a matte surface without performing coating. A resin sheet can be realized.

It is a section schematic diagram by one embodiment of a resin sheet by the present invention. It is the cross-sectional schematic by another embodiment of the resin sheet by this invention. 1 is a schematic cross-sectional view of one embodiment of a fiber-reinforced composite molded body according to the present invention.

<Resin sheet>
As shown in FIG. 1, the resin sheet 1 according to the present invention has a layer structure in which a resin layer 11 is provided on one surface of a first release sheet 21 </ b> A. In the embodiment of the present invention, as shown in FIG. 2, the second release sheet 21B is provided on the side of the resin layer 11 opposite to the side on which the first release sheet 21A is provided. It may be. In the present specification, the first release sheet 21A and the second release sheet 21B are collectively referred to as a release sheet 21. Hereinafter, each layer which comprises the resin sheet by this invention is demonstrated.

  The resin layer which comprises the resin sheet by this invention is a layer hardened | cured by heating so that it may mention later, and contains an epoxy resin, a hardening | curing agent, and a curing catalyst as an essential component.

  The epoxy resin contained in the resin layer means that a prepolymer having at least one epoxy group is cured by a crosslinking polymerization reaction in combination with a curing agent. Examples of such epoxy resins include bisphenol type epoxy resins such as bisphenol A epoxy resin and bisphenol F epoxy resin, novolak type epoxy resins such as novolac epoxy resin and cresol novolac epoxy resin, biphenyl type epoxy resin, stilbene type epoxy resin, Examples include epoxy resins such as triphenolmethane type epoxy resins, alkyl-modified triphenolmethane type epoxy resins, triazine nucleus-containing epoxy resins, dicyclopentadiene-modified phenol type epoxy resins, and also phenol novolac resins, cresol novolac resins, bisphenol A A triazine ring such as a novolak-type phenol resin such as a novolak resin, a phenol resin such as a resol phenol resin, a urea (urea) resin, or a melamine resin. Resins, unsaturated polyester resins, bismaleimide resins, polyurethane resins, diallyl phthalate resins, silicone resins, resins having a benzoxazine ring, cyanate ester resins. Among these epoxy resins, in the present invention, an epoxy resin having a rigid structure such as a biphenyl skeleton, a bisphenol skeleton, or a stilbene skeleton in the main chain is preferable, more preferably a bisphenol type epoxy resin, and particularly preferably a bisphenol A type. It is an epoxy resin.

  The above-described bisphenol A type epoxy resin may be liquid at room temperature or solid at room temperature depending on the number of repeating units of the bisphenol skeleton. A bisphenol A type epoxy resin having a main chain of 0 to 1 is liquid at normal temperature, and a bisphenol A type epoxy resin having a main chain of 2 to 10 is solid at normal temperature. Such a relatively low molecular weight bisphenol A type epoxy resin has crystallinity, and even a solid one that is crystallized at room temperature rapidly melts and changes to a low-viscosity liquid when the temperature reaches the melting point or higher. Therefore, as described later, in the step of providing the resin layer on the surface of the prepreg or the fiber reinforced plastic, the resin composition adheres to the prepreg or the fiber reinforced plastic by heating and solidifies, whereby the resin layer and the fiber reinforced plastic are solidified. Adhesion strength can be increased because of adhesion. In addition, such a relatively low molecular weight bisphenol A type epoxy resin has a high crosslink density, and therefore has high mechanical strength, good chemical resistance, high curability, and hygroscopicity (because the free volume is small). ) Is also small.

  In the present invention, as the bisphenol A type epoxy resin, it is preferable to use a bisphenol A type epoxy resin that is solid at room temperature and a bisphenol A type epoxy resin that is liquid at room temperature. By using both solid and liquid at room temperature, it is possible to obtain flexibility while maintaining mechanical strength, so that flexibility can be obtained while maintaining the mechanical strength inherent to the resin. it can. As a result, the fiber reinforced composite molded body with a resin layer on the surface has improved surface rub resistance, etc., and also realized a fiber reinforced composite molded body with excellent cross-section and recessed design on the surface. it can. As the bisphenol A type epoxy resin solid at room temperature, those having a glass transition temperature in the range of 50 to 70 ° C. are preferable from the viewpoint of mechanical strength and heat resistance. Specifically, as a bisphenol A type epoxy resin having a main chain of 0 to 1 which is liquid at normal temperature, JER828 manufactured by Japan Epoxy Resin Co., Ltd. is a bisphenol A type epoxy having a main chain of 2 to 10 which is solid at normal temperature. Examples of the resin include JER1001 manufactured by Japan Epoxy Resin Co., Ltd.

  The blending ratio of the bisphenol A type epoxy resin that is liquid at normal temperature and the bisphenol A type epoxy resin that is solid at normal temperature depends on the use application of the fiber reinforced composite molded product, but is 0: 100 to 75:25 on a mass basis. It is preferable that it is contained in a proportion. By setting the blending ratio of both in the above range, it is possible to obtain a fiber-reinforced composite molded body having a more excellent appearance design.

  In this invention, acrylic resin may be contained as resin other than the above-mentioned epoxy resin as a resin layer. By containing the acrylic resin, initial tackiness can be imparted to the resin sheet. Further, since the toughness can be imparted to the resin layer while maintaining the adhesive strength with the fiber reinforced plastic as the adherend, the surface of the fiber reinforced composite molded body such as CFRP is protected by providing the resin layer on the surface. Functions can be added.

  The acrylic resin that can be used in the present invention can be used without particular limitation as long as it can undergo a crosslinking reaction with the epoxy resin described later. For example, methyl (meth) acrylate, ethyl (meth) acrylate, Propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, (Meth) acrylic acid alkyl esters such as octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, these acrylate monomers, maleic acid, itaconic acid, (meth) acrylic 2-hydroxyethyl acid, 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid Functional group-containing monomers such as N, methylolacrylamide, n-butoxy-N-methylolacrylamide, sodium 2-acrylamido-2-methyl-1-propanesulfonate, diacetone acrylamide, glycidyl (meth) acrylate, and styrene And acrylic acid ester copolymers obtained by copolymerization with monomers such as vinyltoluene, vinyl acetate, (meth) acrylonitrile, vinyl chloride, vinylidene chloride, and ethyl vinyl ether.

  Among the above copolymers, a binary copolymer of methyl methacrylate-butyl acrylate-methyl methacrylate or a modified product thereof can be preferably used. A binary block copolymer comprising such a methacrylic acid ester polymer block (hereinafter sometimes abbreviated as MMA) and a butyl acrylate polymer block (hereinafter sometimes abbreviated as BA) is preferable. In the MMA-BA-MMA binary copolymer, the MMA portion becomes a “hard” segment and the BA portion becomes a “soft” segment. Toughness (flexibility) can be imparted by adding an acrylic resin to the epoxy resin, but heat resistance and transparency may be lowered. If the acrylic resin has both the “hard” and “soft” segments as described above, the “hard” segment will contribute to heat resistance, and the “soft” segment will contribute to toughness and flexibility. It is considered to have toughness and retain excellent strength even in a high temperature environment.

  The above-described binary copolymer of MMA-BA-MMA can be produced using general living radical polymerization. Among these, from the viewpoint of easy control of the polymerization reaction, it can be suitably produced by primordial transfer radical polymerization. The atom transfer radical polymerization method is a polymerization method using an organic halide or a sulfonyl halide compound as an initiator and a metal complex as a catalyst. When producing a binary copolymer of MMA-BA-MMA by the living radical polymerization method, a method of sequentially adding monomer units, a method of polymerizing the next polymer block using a polymer synthesized in advance as a polymer initiator, Examples thereof include a method in which polymer blocks polymerized separately are combined by reaction, and it is preferable to produce a MMA-BA-MMA binary copolymer by a method in which monomer units are sequentially added.

  In the method of producing a MMA-BA-MMA binary copolymer by sequential addition of monomer units, the order of addition of the methacrylic acid ester constituting the MMA block and the butyl acrylate constituting the BA block is as follows. There are a method of adding a butyl acrylate monomer after polymerizing a methacrylic acid ester monomer and a method of adding a methacrylic acid ester monomer after first polymerizing a butyl acrylate monomer. The polymerization control is easier when the MMA block is polymerized from the polymerization terminal of the BA block.

  The ratio of MMA to BA can be controlled by the amount of monomer introduced when the living radical polymerization reaction is performed. The ratio of the MMA block to the BA block in the MMA-BA-MMA binary copolymer increases the toughness and flexibility of the cured resin (that is, the resin layer) when the BA block ratio increases, When the ratio of the MMA block is increased, the heat resistance of the resin layer is improved. In the present invention, from the viewpoint of toughness and heat resistance of the resin layer, the ratio of the MMA block to the BA block is preferably 1: 1 to 50: 1 in the number of monomer units.

  The above-mentioned binary copolymer of MMA-BA-MMA may be a modified product in which a functional group such as carboxylic acid, hydroxyl group or amide group is introduced into a part of the BA block or MMA block. By using such a modified product, the heat resistance is further improved and the compatibility with the epoxy resin described above is also improved, so that the function as a protective layer of the fiber-reinforced composite molded body is further improved.

  When the MMA-BA-MMA binary copolymer is added to the above epoxy resin, the MMA block portion is compatible with the epoxy resin and the BA block portion is not compatible with the epoxy resin. Self-organization occurs. As a result, a sea-island structure in which the epoxy resin is the sea and the acrylic resin is the island appears before the resin is cured. In addition, when the functional group as described above is introduced into the MMA-BA-MMA binary copolymer, the compatibility between the epoxy resin and the acrylic resin is improved, so that the island portion is reduced, and apparently, Both are in a compatible state. By developing such a sea-island structure and an apparent compatibility state, it is possible to avoid interfacial fracture, to have excellent adhesion to the surface of the fiber-reinforced composite molded body, and to improve the function as a protective layer Can do. Moreover, since the size of the formed sea-island structure is on the nano order, a protective layer having excellent transparency can be formed.

  In order to express the sea-island structure as described above, the epoxy resin and the modified acrylic resin (MMA-BA-MMA binary copolymer) are 97.5: 2.5 to 77.0: It is preferable to mix | blend in the ratio of 23.0. When both are blended in the above ratio, the acrylic resin (island) is dispersed in the form of nano-order fine particles in the epoxy resin (sea), and an apparent compatibility state can be expressed.

  In the case of having the sea island structure as described above, since the acrylic resin is compatible or dispersed in the epoxy resin, transparency is not impaired even when the composition is cured to obtain a resin. Therefore, as will be described later, even when a resin layer is provided on the surface of the fiber-reinforced composite molded body, the appearance unique to the fiber-reinforced material is not impaired.

  The reaction between the acrylic resin and the epoxy resin proceeds by heating or the like and the resin layer is cured. In the present invention, a curing agent is included in the resin layer in order to promote the curing reaction. As the curing agent, a known curing agent generally used for epoxy resins can be used. In the present invention, dicyandiamide (DICY), a latent amine compound, and a thiol compound can be preferably used. These curing agents are preferable because they are superior in storage stability and have a pot life of several weeks even at room temperature storage compared to acid anhydride curing agents and phenol curing agents.

  The curing agent is preferably contained in the range of 0.59 to 1.08 phr with respect to the epoxy resin. By setting the mixing ratio of the curing agent within this range, a resin sheet having excellent transparency and storage stability can be realized. Needless to say, if the addition amount of the curing agent is small, the curability deteriorates and the adhesive strength with the adherend decreases. On the other hand, when the content of the curing agent is increased, the transparency and pot life are decreased, and the unreacted curing agent remains even after the resin layer is cured, so that the adhesive strength between the resin layer and the FRP is decreased. In some cases.

  The resin layer contains a curing catalyst in addition to the above components. As the curing catalyst, known curing agents generally used for epoxy resins can be used. In the present invention, aliphatic amine, aromatic amine, aliphatic dimethylurea, aromatic dimethylurea, and imidazole are used. It can be preferably used. Examples of the aliphatic amine-based curing catalyst include diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylene diamine (MXDA). Examples of the aromatic amine-based curing catalyst include diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), diaminodiphenylsulfone (DDS) and the like. Examples of the aliphatic or aromatic dimethylurea curing catalyst include dimethylurea obtained from isophorazine isocyanate and dimethylamine, dimethylurea obtained from xylylene isocyanate and dimethylamine, hexamethylene diisocyanate and dimethylamine, And dimethylurea obtained from the above. By using these curing catalysts, it is possible to improve the storage stability of the resin sheet, and it is possible to maintain excellent adhesive strength while maintaining colorless transparency even after the resin layer is cured.

  The resin layer of the resin sheet may contain an ultraviolet absorber and a light stabilizer as essential components. By including such a component, the fiber reinforced plastic as the adherend can be protected from ultraviolet rays and the like, and a fiber reinforced composite formed body excellent in weather resistance can be realized.

  As the UV absorber, conventionally known ones can be used, for example, organic compounds such as benzotriazole compounds and benzophenone compounds, inorganic compounds composed of finely divided zinc oxide, cerium oxide and the like. Is mentioned. It is preferable that 1-30 mass% of ultraviolet absorbers are contained in the resin layer in conversion of solid content, More preferably, it is 5-20 mass%. When the content of the ultraviolet absorber is less than 1% by mass, the weather resistance may not be improved. On the other hand, even if the ultraviolet absorber is added in an amount exceeding 30% by mass, the weather resistance is more than that. It cannot be expected to improve, leading to an increase in manufacturing cost.

  Examples of the light stabilizer include 2,2,6,6, -tetramethyl-4-piperidyl methacrylate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, and bis (1, 2,2,6,6-pentamethyl-4-piperidyl) sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, bis (1-undecanoxy-2,2,6,6-tetramethyl) Hindered amine light stabilizers such as piperidin-4-yl) carbonate, benzophenone light stabilizers such as octabenzone, 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3- Tetramethylbutyl) phenol, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- [2-hydroxy-3- (3,4,5,6-tetrahi Benzotriazole-based light stabilizers such as lophthalimido-methyl) -5-methylphenyl] benzotriazole, 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chlorobenzotriazole, 2,4 -Benzoate type such as di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5 Examples include triazine light stabilizers such as-[(hexyl) oxy] phenol, and among these, hindered amine light stabilizers can be preferably used.

  The light stabilizer is preferably contained in the resin layer in an amount of 0.5 to 20% by mass in terms of solid content, and more preferably 1 to 10% by mass. When the content of the light stabilizer is less than 0.5% by mass, the weather resistance may not be improved. On the other hand, even if the light stabilizer is added in an amount exceeding 20% by mass, the weather resistance is not improved. Further improvement cannot be expected, resulting in an increase in manufacturing cost.

  For the resin layer constituting the resin sheet, if necessary, for example, processability, heat resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, release properties, flame retardancy, antifungal properties, For the purpose of improving and modifying electrical characteristics, strength, etc., for example, coloring of lubricants, plasticizers, fillers, fillers, antistatic agents, antiblocking agents, crosslinking agents, antioxidants, dyes, pigments, etc. Agents, etc. may be added. Further, if necessary, a coupling agent such as silane, titanium, and aluminum can be further included. As a result, the adhesion between the resin and the adherend and the resin and the core material described later can be improved.

  The resin sheet is prepared by mixing the above-mentioned components, kneading and dispersing as necessary to dissolve in an appropriate solvent to form a coating solution, coating the release sheet, drying, and then releasing the other release sheet. Can be manufactured by bonding. The mixing or dispersing method is not particularly limited, and a usual kneading and dispersing machine such as a two-roll mill, a three-roll mill, a pebble mill, a tron mill, a Szegvari attritor, a high-speed impeller disperser, a high-speed stone mill, A high speed impact mill, a desper, a high speed mixer, a ribbon blender, a kneader, an intensive mixer, a tumbler, a blender, a desperser, a homogenizer, an ultrasonic disperser, and the like can be applied. When multiple types are used as the hard epoxy resin, these are first mixed and stirred, then the curing agent is mixed and stirred, diluted with a solvent, and then the soft epoxy resin is mixed and stirred, and then the acrylic resin Are preferably mixed and stirred.

  The application method to the release sheet is not particularly limited. For example, roll coating, reverse roll coating, transfer roll coating, gravure coating, gravure reverse coating, comma coating, rod coat, blade coating, bar coating, Wire bar coat, die coat, lip coat, dip coat, etc. can be applied. The thermosetting resin composition may be applied to the release surface of the first release sheet 21A by the above coating method and dried, and then the second release sheet 21B may be bonded.

  The resin layer may be composed only of the resin composition containing the above-described components, but may be one in which the core material is impregnated with the resin composition. The core material is preferably a woven fabric or a non-woven fabric, and various conventionally known woven or non-woven fabrics can be used. Examples thereof include heat-resistant plastic fibers such as liquid crystal polymers, glass fibers, aramid fibers, and carbon fibers. A woven fabric and a non-woven fabric composed of these can be used. In addition, nanofibers or the like can be used as a core material in order to increase transparency.

  As a release sheet used for the resin sheet according to the present invention, one surface is a mat surface having a surface gloss value (60 ° incidence) of 20% or less measured by a specular gloss measurement method based on JIS Z 8741. Use what you have. As will be described later, when the resin layer is provided on the mat surface of the release sheet, the surface of the resin layer in contact with the release sheet adapts to the unevenness of the mat surface, and the resin layer is cured. A resin layer surface on which the mat surface of the sheet is shaped is obtained. As a result, a mat-like protective layer can be formed on the surface of the fiber-reinforced molded body. The release sheet having such a surface gloss value is obtained by embossing the surface of the release sheet as described later using a predetermined satin roll, or by incorporating fine particles such as silica in the release sheet. Can be obtained.

  Any release sheet having a surface gloss value as described above can be used without particular limitation, and a conventionally known release film, separate paper, separate film, separate paper, release film, release paper, etc. are preferably used. Can be used. Moreover, you may use what formed the release layer in the single side | surface or both surfaces of base materials for release sheets, such as quality paper, a coated paper, an impregnation paper, and a plastic film. The release layer is not particularly limited as long as it is a material having releasability. For example, silicone resin, organic resin-modified silicone resin, fluororesin, aminoalkyd resin, melamine resin, acrylic resin, polyester resin, etc. There is. These resins can be used in any of emulsion type, solvent type and solventless type.

  The release layer is formed by applying a coating liquid in which the release layer component is dispersed and / or dissolved on one side of the release sheet base film, followed by heat drying and / or curing. As a coating method of the coating liquid, a known and arbitrary coating method can be applied, for example, roll coating, gravure coating, spray coating and the like. Moreover, you may form a release layer in the whole surface or a part of at least single side | surface of a base film as needed.

  Moreover, when it is set as the resin sheet which provided the 1st release sheet 21A and the 2nd release sheet 21B on both surfaces of the resin layer 11 as shown in FIG. 2, the 1st release sheet 21A and the 2nd release sheet 21B may be the same or different.

  The peeling force of the first and second release sheets is preferably about 1 to 2000 mN / cm, and more preferably 100 to 1000 mN / cm with respect to the resin sheet. When the release force of the release layer is less than 1 mN / cm, the release force is weak, and it peels off or partially floats. Moreover, when larger than 2000 mN / cm, the peeling force of a release paper is strong and it becomes difficult to peel. From the viewpoint of stable releasability and workability, it is preferable to form a release layer using an addition and / or polycondensation-type curable silicone resin for release paper mainly composed of polydimethylsiloxane.

<Method for producing fiber-reinforced composite molded product>
The method for producing a fiber-reinforced composite molded body according to the first embodiment of the present invention includes: 1) a resin sheet on a prepreg formed by impregnating reinforcing fibers with an uncured or semi-cured thermosetting resin or thermoplastic resin. The step of laminating the resin sheet so that the resin layer side of the layer is opposed to each other, 2) The step of heating the layered product under pressure to form the prepreg and the resin layer, and 3) A step of peeling the release sheet from the resin sheet to form a fiber-reinforced composite molded body.

  In the above-described curing molding step (2), a laminate of a prepreg and a resin sheet is placed in a molding die and heated under pressure to cure the resin layer of the prepreg and the resin sheet, thereby producing a fiber. An integrated fiber-reinforced composite body in which a resin layer is formed on the surface of the reinforced plastic can be formed. Moreover, it may be packaged in an autoclave bag instead of a molding die, and the inside of the autobag package may be kept in a vacuum and thermally cured by an autoclave apparatus. The prepreg used may be a single layer or a laminate of a plurality of layers.

  The method for producing a fiber-reinforced composite molded body according to the second embodiment of the present invention is as follows: 1) Under pressure, a prepreg formed by impregnating a reinforcing fiber with an uncured or semi-cured thermosetting resin or thermoplastic resin is used. A step of heating to form a fiber reinforced plastic, 2) a step of bonding the resin sheet to the surface of the fiber reinforced plastic so that the resin layer side of the resin sheet faces, and 3) the lamination A step of curing the resin layer of the body, and 4) a step of peeling the release sheet from the resin sheet to form a fiber-reinforced composite molded body. In the manufacturing method of the fiber-reinforced composite molded body according to the first embodiment, the prepreg and the resin sheet are overlapped to integrally cure the prepreg and the resin layer. The fiber reinforced plastic is formed by curing the prepreg to form a fiber reinforced plastic, and then bonding the resin sheet to the surface to cure the resin layer. To do.

  Moreover, the manufacturing method of the fiber reinforced composite molded object by 3rd embodiment of this invention is 1) bonding a resin sheet to the sheet | seat which consists of a reinforced fiber so that the resin layer side of an above-mentioned resin sheet may oppose. Step of forming a laminated body 2) The laminated body is placed in a mold, an uncured thermosetting resin or a thermoplastic resin is injected into the mold under pressure, and the thermosetting is applied to reinforcing fibers. 3) a step of impregnating with a thermoplastic resin or a thermoplastic resin, 3) a step of curing the thermosetting resin or thermoplastic resin, and 4) a step of peeling the release sheet from the resin sheet to form a fiber reinforced composite molded body. Is included. The manufacturing method according to the first and second embodiments described above uses a prepreg, whereas the manufacturing method according to the third embodiment is a reinforcing fiber not impregnated with a thermosetting resin or a thermoplastic resin. When resin transfer molding is performed using a sheet made of the above, a resin sheet is laminated on a sheet made of reinforcing fibers in advance, and resin transfer molding is performed using the laminate, whereby a resin is formed on the surface of the FRP molded body. A fiber-reinforced composite molded body in which layers are integrally formed can be obtained. In addition, although the sheet | seat which consists of a reinforced fiber can also use what is not impregnated with resin at all, you may use what impregnated a small amount of resin for shaping | molding.

  The method for producing a fiber-reinforced composite molded body according to the first to third embodiments described above uses a resin sheet provided with a release sheet only on one surface as shown in FIG. Needless to say, a resin sheet having release sheets on both sides as shown in FIG. 2 can be used. In that case, the release sheet on one side may be peeled off before the resin sheet is bonded to the prepreg or reinforcing fiber.

  The reinforcing fiber constituting the prepreg is not particularly limited, and for example, carbon fiber, glass fiber, aramid fiber, boron fiber, steel fiber and the like can be used. Among these, carbon fibers are preferable because they have good mechanical properties after molding. Examples of the carbon fiber include polyacrylonitrile (PAN) -based carbon fiber and pitch-based carbon fiber. Further, the form and arrangement of the reinforcing fibers are not particularly limited, and there are a sheet in which long fibers are aligned in one direction, a cloth (woven fabric), a tow, a mat, a knit, and a sleeve.

  The thermosetting resin impregnated in the above-mentioned reinforcing fiber is not particularly limited, and examples thereof include an epoxy resin, a polyester resin, a vinyl ester resin, a phenol resin, a maleimide resin, a polyimide resin, and a BT resin. preferable. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, fluorene type epoxy resin, or a combination thereof. Resins etc. are preferably used. Further, a polyfunctional epoxy resin having three or more functions may be used. For example, a phenol novolac type epoxy resin, a cresol type epoxy resin, a glycidylamine type epoxy resin such as tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, tetraglycidylamine, tetrakis ( A glycidyl ether type epoxy resin such as glycidyloxyphenyl) ethane or tris (glycidyloxymethane), or a combination thereof is preferably used.

  The thermosetting resin has an effect on the performance and does not affect the performance. Additives such as a curing agent, thermoplastic resin, rubber particles, soluble rubber, core shell rubber, etc. for the purpose of control of resin viscosity and prepreg handling. May be blended. Curing agents include aromatic amines such as diphenylmethane and diaminodiphenylsulfone, aliphatic amines, imidazole derivatives, dicyandiamide, tetramethylguanidine, thiourea addition amines, carboxylic acid anhydrides such as methylhexahydrophthalic anhydride, It is preferable to add a curing agent such as a carboxylic acid hydrazide, a carboxylic acid amide, a polyphenol compound, a novolac resin, a polymercaptan, a Lewis acid complex such as boron trifluoride ethylamine complex.

  The fiber reinforced composite molded body 2 obtained as described above is obtained by integrating the fiber reinforced composite material 3 and the resin layer 11 as shown in FIG. 3, and the surface of the resin layer 11 is a surface gloss. The matte surface has a value (60 ° incidence) of 20% or less. When the resin sheet in which the resin is uncured is bonded to the prepreg and pressed, a part of the resin oozes into the cross stitch (that is, the gap between the fibers) or the intersection between the warp and the weft. By being cured in a state, it is considered that a molded body having a smooth surface and having no cross eyes or recessed holes and excellent appearance design can be obtained. Therefore, the resin layer can be formed simultaneously with or subsequent to the prepreg curing process without washing the surface of the fiber-reinforced plastic after molding and without coating after polishing, as in the past. A fiber-reinforced composite molded body having excellent weather resistance can be obtained, and a fiber-reinforced composite molded body having a matte-like protective layer can be obtained by using a resin sheet as in the present invention. .

  Examples The present invention will be described in more detail with reference to examples, but the present invention is not limited to the contents of these examples. In addition, each composition of each layer is the mass part of solid content except a solvent.

Example 1
50 parts of bisphenol A type epoxy resin (JER828, manufactured by Japan Epoxy Resin Co., Ltd.), 100 parts of bisphenol A type epoxy resin (JER1001, manufactured by Japan Epoxy Resin Co., Ltd.), and dicyandiamide (DICY7, manufactured by Japan Epoxy Resin Co., Ltd.) as a curing agent. ) And 5 parts of a latent amine compound (Amicure MY-H, manufactured by Ajinomoto Fine Techno Co., Ltd.) as a curing catalyst were charged into a stirrer and mixed to obtain a composition 1 for forming a resin layer. .

A coating mat PET film (release mat 1017-6, manufactured by Kimoto Co., Ltd.) having a thickness of 25 μm and a surface gloss value (incident at 60 °) of 2% measured by a specular gloss measurement method based on JIS Z 8741 is prepared. On the mat surface, a mixed solution of 100 parts of silicone resin (TPR6722, manufactured by Momentive Performance Materials LLC) and 1 part of curing catalyst (CM6701, manufactured by Momentive Performance Materials LLC) has a coating amount of 0 when dried. A release sheet was prepared by coating so as to be 3 g / m ² .

On the surface (matte surface) coated with the silicone resin of the obtained release sheet, the composition 1 for resin layer formation was coated with a comma coater so that the coating amount when dried was 1000.3 g / m ^2. And after drying at 100 degreeC for 3 minute (s) and forming a resin layer, the resin sheet was obtained by bonding the light peeling separator (SP-PETO1BU, the Tosero company make) on the surface of the resin layer.

<Preparation of fiber reinforced composite molded body 1>
The resin sheet separator film was peeled off, and the exposed surface of the resin layer was attached to an uncured carbon prepreg (TR3110, manufactured by Mitsubishi Rayon Co., Ltd.). Next, the carbon prepreg and the resin layer were cured by pressing with a precision press machine for 1 hour under a pressure of about 0.2 MPa and 130 ° C. Thereafter, the fiber-reinforced composite molded body 1 was produced by peeling the coating mat PET film.

Example 2
Instead of the resin layer forming composition 1 used in Example 1, 50 parts of bisphenol A type epoxy resin (JER828, manufactured by Japan Epoxy Resin Co., Ltd.) and bisphenol A type epoxy resin (JER1001, manufactured by Japan Epoxy Resin Co., Ltd.) Fiber reinforced composite molded body 2 in the same manner as in Example 1 except that the resin layer forming composition 2 comprising 100 parts of the above and 15 parts of dicyandiamide (DICY7, manufactured by Japan Epoxy Resin Co., Ltd.) as the curing agent was used. Was made.

Example 3
Instead of the resin layer forming composition 1 used in Example 1, 50 parts of bisphenol A type epoxy resin (JER828, manufactured by Japan Epoxy Resin Co., Ltd.) and bisphenol A type epoxy resin (JER1001, manufactured by Japan Epoxy Resin Co., Ltd.) 100 parts, 64 parts of thiol-based curing agent (QX-40, manufactured by Japan Epoxy Resin Co., Ltd.) as a curing agent, and aliphatic dimethylurea (UCAT3513N, manufactured by Sun Apro) as a curing catalyst A fiber-reinforced composite molded body 3 was produced in the same manner as in Example 1 except that the composition 3 was used.

  The surface gloss value measured by the specular gloss measurement method based on JIS Z8741 using the handy gloss meter (Gloss Checker IG-320, manufactured by HORIBA, Ltd.) Was measured. The results were as shown in Table 1 below.

  Further, the adhesion between the fiber reinforced material of the fiber reinforced composite molded body and the resin layer was evaluated by an adhesion test based on ASTM D3359. Adhesive tape (# 610 tape, manufactured by 3M Company) is applied to the place where the surface of the fiber reinforced composite molded body is cross-cut to 1 mm square, and after holding for 2 minutes, the adhesive tape is peeled off so that the peeling angle is 90 °. In addition, the case where the resin layer was not peeled off was indicated as “◯”, and the case where the resin layer was peeled off was indicated as “X”. The evaluation results were as shown in Table 1 below.

1: Resin sheet 2: Fiber reinforced composite molded article 3: Fiber reinforcing material 11: Resin layer 21: Release sheet 21A: First release sheet 21B: Second release sheet

Claims (10)

A resin sheet comprising a release sheet and a resin layer provided on one surface of the release sheet,
One surface of the release sheet is provided with a matte surface having a surface gloss value (60 ° incidence) of 20% or less measured by a specular gloss measurement method according to JIS Z 8741.
The resin layer comprises at least an epoxy resin, a curing agent, and a curing catalyst;
The resin sheet, wherein the resin layer is provided on a mat surface of the release sheet.   The resin sheet according to claim 1, wherein the curing agent is at least one selected from the group consisting of dicyandiamide, a latent amine compound, and a thiol compound.   The resin sheet according to claim 1 or 2, wherein the curing catalyst is at least one selected from the group consisting of aliphatic amines, aromatic amines, aliphatic dimethylureas, aromatic dimethylureas, and imidazoles.   The resin sheet according to claim 1, wherein the epoxy resin is a bisphenol type epoxy resin.   The bisphenol-type epoxy resin is composed of two types of bisphenol-type epoxy resins: a bisphenol-type epoxy resin that is liquid at normal temperature and a bisphenol-type epoxy resin that is solid at normal temperature and has a glass transition temperature in the range of 50 to 170 ° C. The resin sheet as described in 2.   The resin sheet according to any one of claims 1 to 5, wherein the resin layer further comprises an acrylic resin. A method for producing a fiber-reinforced composite molded body,
To the prepreg formed by impregnating the reinforcing fiber with an uncured or semi-cured thermosetting resin or thermoplastic resin, the resin layer side of the resin sheet according to any one of claims 1 to 5 is opposed. The resin sheet is laminated to form a laminate,
The laminate is heated and molded under pressure to cure the prepreg and resin layer,
Peeling the release sheet from the resin sheet to form a fiber reinforced composite molded body,
The manufacturing method of the fiber reinforced composite molded object characterized by including this. A method for producing a fiber-reinforced composite molded body,
A prepreg formed by impregnating a reinforcing fiber with an uncured or semi-cured thermosetting resin or thermoplastic resin is heated under pressure to form a fiber reinforced plastic,
The resin sheet is bonded to the surface of the fiber reinforced plastic so that the resin layer side of the resin sheet according to any one of claims 1 to 5 is opposed to form a laminate,
Curing the resin layer of the laminate,
Peeling the release sheet from the resin sheet to form a fiber reinforced composite molded body,
The manufacturing method of the fiber reinforced composite molded object characterized by including this. A method for producing a fiber-reinforced composite molded body,
The resin sheet is bonded to a sheet composed of reinforcing fibers so that the resin layer side of the resin sheet according to any one of claims 1 to 5 is opposed to form a laminate,
The laminated body is placed in a mold, an uncured thermosetting resin or thermoplastic resin is injected into the mold under pressure, and reinforcing fibers are impregnated with the thermosetting resin or thermoplastic resin. Let
Curing the thermosetting resin or thermoplastic resin,
Peeling the release sheet from the resin sheet to form a fiber reinforced composite molded body,
The manufacturing method of the fiber reinforced composite molded object characterized by including this.   A fiber-reinforced composite molded article obtained by the method according to any one of claims 7 to 9.