Carrier film for molding fiber-reinforced composite materials, carrier film-coated fiber-reinforced composite material, and molded product

Abstract

The problem that this invention aims to solve is to provide a carrier film for molding fiber-reinforced composite materials that is less prone to molding defects and less prone to peeling residue, even when a radical polymerizable compound is used as the resin. [Solution] The present invention solves the above problem with a carrier film for molding fiber-reinforced composite materials, wherein the carrier film comprises at least a nylon layer and at least a propylene block copolymer and an acid-modified polyolefin.

Description

[Technical Field]

[0001] The present invention relates to a carrier film for molding fiber-reinforced composite materials, a carrier film-coated fiber-reinforced composite material, and a molded article. [Background technology]

[0002] FRP (fiber-reinforced composite material), which is made by adding carbon fiber or glass fiber as a reinforcing material to resin, is lightweight and highly rigid, making it suitable for a wide range of applications in leisure and sports equipment such as golf shafts, fishing rods, tennis rackets, and ski poles; automobiles and motorcycles; aerospace and aircraft-related products; industrial equipment; nursing care and welfare; construction, civil engineering and interior design; attractions; robots; drones; air mobility; medical equipment; high-speed rotating bodies; pressure tanks; and water tanks. Carbon fiber is particularly often used as a reinforcing material from the perspective of weight reduction. One method of manufacturing FRP (fiber-reinforced plastic) is the prepreg method, which uses prepregs, which are sheet-like intermediate materials made by impregnating fibers with resin. In this prepreg method, multiple prepreg sheets are laminated together, and then the resin is cured to form the FRP. Molded products using prepreg sheets are characterized by their excellent mechanical strength due to their high fiber content. The resins used include epoxy resins, unsaturated polyester resins, vinyl ester resins, and phenolic resins. When epoxy resin is used in the prepreg, it is necessary to store the prepreg at low temperatures (-18°C), and the curing process takes a long time, raising concerns about overall high energy costs. Vinyl ester resins and unsaturated polyester resins have excellent curability and storage properties, but suffer from insufficient mechanical properties. To address these issues, a prepreg sheet using a radical polymerizable composition containing a urethane (meth)acrylate compound has been proposed (Patent Document 1).

[0003] When manufacturing prepregs, a resin composition is applied to a carrier film, then reinforcing fiber material is supplied in a unidirectional manner to impregnate the resin composition, and a carrier film is placed over it to form a prepreg sheet. After the prepreg sheet is heat-cured using methods such as autoclave molding or oven molding, the carrier film is manually peeled off to form an FRP (fiber-reinforced plastic) component. At this time, if any residue of the carrier film remains after peeling, it may lead to serious quality problems. For this reason, ethylene-based resins, which have excellent peelability, are sometimes used instead of propylene-based resins, which have poor peelability. However, ethylene-based resins are easily stretched, resulting in poor quality stability of molded products. Therefore, a five-layer film with an ethylene-based resin layer on the outer layer has been developed (Patent Document 2). Furthermore, when a radically polymerizable composition is used as the resin, oxygen in the air also acts as a polymerization inhibitor during radical polymerization. Therefore, if oxygen dissolution progresses within the prepreg during storage, the gel time of the prepreg will be delayed, the curing reaction will not proceed as designed, and problems such as incomplete curing or blistering during curing will occur, leading to molding defects. To solve this problem and produce a prepreg with a smooth surface, an oxygen permeability of 200 ml / m³ is used. 2 A prepreg using a carrier film with a temperature of 24h·atm or less has been proposed (Patent Document 3). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-214463 [Patent Document 2] Japanese Patent Application Publication No. 11-235797 [Patent Document 3] International Publication No. 2021 / 187030 [Overview of the project] [Problems that the invention aims to solve]

[0005] In view of the above, the problem that the present invention aims to solve is to provide a carrier film for molding fiber-reinforced composite materials that is less prone to molding defects even when a radical polymerizable compound is used as the resin, has excellent release properties, and allows for easy visualization of any remaining residue after peeling. [Means for solving the problem]

[0006] The present invention solves the above problems with a carrier film for molding fiber-reinforced composite materials, wherein the carrier film comprises at least a nylon layer and at least a propylene block copolymer and an acid-modified polyolefin. [Effects of the Invention]

[0007] The carrier film of the present invention is suitable for use as a carrier film for molding fiber-reinforced composite materials because, even when a radical polymerizable compound is used as the resin, molding defects are less likely to occur and peeling residue is less likely to occur. [Modes for carrying out the invention]

[0008] <Career Film> The carrier film of the present invention is a carrier film for molding fiber-reinforced composite materials, comprising at least a nylon layer, and the carrier film comprising at least a propylene block copolymer and an acid-modified polyolefin.

[0009] (Nylon layer) The carrier film of the present invention includes at least a nylon layer. By reducing the gas permeability of the carrier film, the dissolution of oxygen into the fiber-impregnated resin is suppressed, allowing the curing reaction to proceed as designed when manufacturing molded products, and suppressing problems such as molding defects caused by curing defects, such as incomplete curing or blistering during curing.

[0010] Examples of the nylon constituting the nylon layer of the present invention include n-nylons such as nylon 4 (2-pyrrolidone polycondensation), nylon 6 (ε-caprolactam polycondensation), nylon 11 (undecane lactam polycondensation), nylon 12 (lauryl lactam polycondensation), etc., and n,m-nylons such as nylon 66 (hexamethylenediamine-adipic acid copolycondensation), nylon 610 (hexamethylenediamine-sebacic acid copolycondensation), nylon 6I (hexamethylenediamine-isophthalic acid copolycondensation), nylon 6T (hexamethylenediamine-terephthalic acid copolycondensation), nylon 9T (nonanediamine-terephthalic acid copolycondensation), nylon M5T (methylpentanediamine-terephthalic acid copolycondensation), nylon MXD6 (m-xylenediamine-adipic acid copolycondensation), nylon XD10 (xylenediamine-sebacic acid copolycondensation).

[0011] Also, the nylon may be biomass-derived nylon. For example, in 6-nylon, 11-nylon, 12-nylon, 66-nylon, nylon 6 / 66, nylon 6 / 12 or nylon 6 / 66 / 12, etc., those using biomass-derived monomers as part or all of the raw material monomers can be mentioned. Examples of the biomass-derived nylon raw materials include sebacic acid, decamethylenediamine, 1,5-pentanediamine and 11-aminoundecanoic acid that can be synthesized from ricinoleic acid triglyceride, the main component of castor oil, azelaic acid that can be synthesized from the components of sunflower seeds, pentamethylenediamine, γ-aminobutyric acid, etc. that can be synthesized from cellulose.

[0012] From the viewpoints of gas permeability, cost performance and availability stability, the nylon layer of the present invention is preferably composed of nylon 6, nylon 66, nylon MXD6, more preferably composed of nylon 6, nylon 66, and even more preferably composed of nylon 6.

[0013] The nylon constituting the nylon layer of the present invention may be only one kind or two or more kinds. When there are two or more kinds, their combinations and ratios may be arbitrarily set according to the purpose. In addition, the nylon layer may be composed only of nylon, or may be composed of nylon and other components. Examples of the other components include other resins, additives, and the like.

[0014] Examples of the other resins include thermoplastic elastomers such as ethylene-based resins, propylene-based resins, and butene-based elastomers; norbornene-based polymers such as ring-opening polymers (COP) of norbornene-based monomers and norbornene-based copolymers (COC) obtained by copolymerizing norbornene-based monomers and olefins such as ethylene, and hydrogenated products thereof, vinyl alicyclic hydrocarbon polymers, and cyclic polyolefin-based resins such as cyclic conjugated diene polymers. Resins may include recycled materials, including nylon.

[0015] Examples of ethylene-based resins include ultra-low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), linear medium density polyethylene (LMDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), acid-modified polyethylene, polyethylene-based elastomers, and the like. Further, as the ethylene-based resin, polyethylene derived from biomass may be used. For example, biomass-derived low density polyethylene (trade name: SBC818, density: 0.918 g / cm 3 , MFR: 8.1 g / 10 min), biomass-derived low density polyethylene (trade name: SPB681, density: 0.922 g / cm 3 , MFR: 3.8 g / 10 min), biomass-derived linear low density polyethylene (trade name: SLL118, density: 0.916 g / cm 3 , MFR: 1.0 g / 10 min), and the like.

[0016] Examples of propylene-based resins include propylene homopolymers, propylene-α-olefin random copolymers, propylene-α-olefin block copolymers, propylene-ethylene-butene-1 copolymers, metallocene catalyst-based polypropylenes, acid-modified polypropylenes, and polypropylene elastomers. Examples of the above-mentioned additives include antistatic agents, heat stabilizers, nucleating agents, antioxidants, antistatic agents, lubricants, antifogging agents, antiblocking agents, mold release agents, ultraviolet absorbers, colorants, biodegradability enhancers, and compatibilizers. In the present invention, it is preferable that the nylon layer is composed of nylon and additives, or composed solely of nylon.

[0017] (Propylene block copolymer) The carrier film of the present invention comprises a propylene block copolymer. The propylene block copolymer can improve the peelability from the fiber-impregnated resin by increasing the surface roughness of the carrier film of the present invention. Furthermore, by improving the visibility of the carrier film of the present invention, the risk of overlooking any remaining peeled material can be reduced. In addition, the fiber-impregnated resin has favorable wettability, which can suppress molding defects such as the formation of air bubbles between the carrier film and the fiber-impregnated resin.

[0018] As the propylene block copolymer mentioned above, a resin containing propylene and other α-olefins can be used. Examples of α-olefins include ethylene, 1-butene, 1-hexene, 4-methyl·1-pentene, and 1-octene, among which ethylene is preferred due to its excellent heat resistance and impact resistance. The propylene-ethylene block copolymer is not particularly limited, but for example, it can be obtained by polymerizing a polymer block mainly composed of propylene in the first step, and polymerizing an ethylene-propylene copolymer block in the second step.

[0019] The above-mentioned propylene block copolymer preferably has a cloudiness of 20% or more, and more preferably 30% or more, when molded to a thickness of 60 μm using a T-die film deposition method with a cooling roll at 40°C. Using a resin with this cloudiness level provides suitable release properties and visibility.

[0020] The melt flow rate (MFR) of the above propylene block copolymer is preferably 0.5 to 10 g / 10 min (230°C, 21.18 N), and more preferably 2 to 5 g / 10 min, because it facilitates molding and easily provides suitable openability.

[0021] The melting point of the above-mentioned propylene block copolymer is preferably 150°C or higher, and more preferably 160°C or higher, because it facilitates molding and ensures excellent heat resistance.

[0022] (Acid-modified polyolefin) The carrier film of the present invention comprises an acid-modified polyolefin. The acid-modified polyolefin exhibits excellent adhesion to the nylon layer, and when peeling the carrier film of the present invention, it can improve peelability by preventing film residue due to interlayer delamination.

[0023] The above-mentioned acid-modified polyolefin is a copolymer of a polyolefin mainly composed of alkenes having 2 to 6 carbon atoms, such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, and 1-hexene, and (meth)acrylic acid ester components and unsaturated carboxylic acid components. As the polyolefin, alkenes having 2 to 4 carbon atoms, such as ethylene, propylene, isobutylene, and 1-butene, are preferred. Ethylene and propylene are more preferred from the viewpoint of adhesion to nylon, and propylene is even more preferred because it can reduce environmental impact as a monomaterial carrier film. In other words, the carrier film of the present invention preferably contains acid-modified polyethylene or acid-modified polypropylene, and more preferably contains acid-modified polypropylene.

[0024] Examples of the above (meth)acrylic acid ester components include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate. From the viewpoint of ease of availability and adhesiveness, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and hexyl acrylate are more preferred, and methyl acrylate and ethyl acrylate are even more preferred. Furthermore, the (meth)acrylic acid ester component only needs to be copolymerized with the olefin component, and its form is not limited. Examples of copolymerization states include random copolymerization, block copolymerization, and graft copolymerization (graft modification). (Note that "(meth)acrylic acid" means "acrylic acid or methacrylic acid.") Specifically, examples of ethylene-(meth)acrylic acid ester copolymers include Elbaroy (trade name: manufactured by Mitsui Dow Polychemical Co., Ltd.) and Aclift (trade name: manufactured by Sumitomo Chemical Co., Ltd.). These may be used individually or as a mixture of two or more.

[0025] Examples of the unsaturated carboxylic acid components include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, and other unsaturated dicarboxylic acid half-esters and half-amides. Among these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferred, with acrylic acid and maleic anhydride being particularly preferred. Furthermore, the unsaturated carboxylic acid component only needs to be copolymerized with the olefin component, and its form is not limited. Examples of copolymerization states include random copolymerization, block copolymerization, and graft copolymerization (graft modification). Specifically, for example, as an ethylene-acrylic acid copolymer, Nucrel (trade name: manufactured by Mitsui Dow Polychemical Co., Ltd.) is an example. As an ethylene-(meth)acrylic acid ester-maleic anhydride copolymer, Bondine (trade name: manufactured by Tokyo Materials Co., Ltd.) is an example. These may be used individually or as a mixture of two or more.

[0026] Furthermore, the acid-modified polyolefin may be an ethylene-vinyl acetate copolymer (EVA), or a modified EVA obtained by mixing and modifying this EVA as a base resin with one or more of the following: rosin, hydrogenated rosin, rosin ester derivatives, polymerized rosin, terpenes, modified terpene resins, aliphatic petroleum resins, styrene resins, etc. Specific examples of this modified EVA include, for example, "Mersen" manufactured by Tosoh Corporation.

[0027] The acid modification rate of the above-mentioned acid-modified polyolefin is preferably 3 to 40%, more preferably 7 to 35%, and even more preferably 10 to 30%, as it offers an excellent balance between adhesion and suppression of appearance defects such as wrinkles in the film.

[0028] (Exfoliation layer) The carrier film of the present invention preferably further includes a release layer. This release layer becomes a surface layer that comes into contact with the fiber-impregnated resin and peels off well from the fiber-impregnated resin.

[0029] The above-mentioned release layer preferably contains at least the above-mentioned propylene block copolymer. By containing the propylene block copolymer in the release layer, both release properties and visibility are improved, and the effects of the present invention can be achieved. If the carrier film of the present invention has a two-layer structure, i.e., a nylon layer and a release layer, the effects of the present invention can be achieved if the release layer contains a propylene block copolymer and an acid-modified polyolefin.

[0030] The above-mentioned release layer preferably contains 35% by mass or more of the above-mentioned propylene block copolymer, more preferably 50% by mass or more, and even more preferably 70% by mass or more of the above-mentioned propylene block copolymer in the resin components contained in the release layer. By having this content, the carrier film of the present invention can obtain sufficient surface roughness and good release properties.

[0031] The above-mentioned release layer may contain other resins. These other resins can be those exemplified in the nylon layer and are not particularly limited. In particular, from the viewpoint of enabling the carrier film to be a monomaterial film, it is preferable that the carrier film is composed of a propylene block copolymer and a propylene-based resin, and may be composed of a propylene block copolymer alone.

[0032] The above-mentioned release layer may contain additives. Such additives can be those exemplified in the nylon layer, and are not particularly limited.

[0033] (adhesive layer) The carrier film of the present invention preferably further includes an adhesive layer. This adhesive layer has excellent adhesion to the nylon layer and can improve peelability by preventing film residue due to interlayer delamination when the carrier film of the present invention is peeled off.

[0034] The adhesive layer preferably contains the acid-modified polyolefin. The presence of the acid-modified polyolefin in the adhesive layer improves adhesion to the nylon layer and provides good peelability from the fiber-impregnated resin.

[0035] The adhesive layer preferably contains 20% by mass or more of the acid-modified polyolefin in the resin components contained in the adhesive layer, more preferably 40% by mass or more, and even more preferably 60% by mass or more. This content prevents delamination between the nylon layer and the adhesive layer, resulting in good peelability.

[0036] The adhesive layer described above may contain other resins. These other resins are not particularly limited and can be those exemplified in the nylon layer. In particular, from the viewpoint of enabling the carrier film to be a monomaterial film, it is preferable that the carrier film be composed of acid-modified polypropylene and a propylene-based resin, and may be composed solely of acid-modified polypropylene.

[0037] The above adhesive layer may contain additives. Such additives may be those exemplified in the nylon layer, and are not particularly limited.

[0038] The carrier film of the present invention comprises a nylon layer, a release layer, and an adhesive layer, preferably the release layer comprises at least a propylene block copolymer, and the adhesive layer comprises at least an acid-modified polyolefin. This carrier film can achieve both release properties and gas permeability.

[0039] (surface) The carrier film of the present invention preferably further includes a surface layer. This surface layer improves the film-forming properties and handling characteristics of the carrier film, and can further reduce the gas permeability of the carrier film. The surface layer preferably contains a propylene resin, and more preferably contains a propylene homopolymer. Furthermore, if the surface layer is adjacent to the nylon layer, the surface layer may also contain the acid-modified polyolefin.

[0040] Furthermore, the above-mentioned propylene-based resin is preferably one whose MFR (Metal Fiber Retention Rate) under measurement conditions of 230°C and 2.16 kg load is 0.5 to 30.0 g / 10 min, and more preferably 2.0 to 15.0 g / 10 min. If the MFR is within this range, the shrinkage of the film during storage is reduced, and the film-forming properties of the film are also improved.

[0041] The content of the propylene resin is preferably 50% to 99% by mass, more preferably 50% to 95% by mass, and even more preferably 50% to 90% by mass, relative to the total amount of resin components contained in the surface layer. Within this range, the rigidity of the film can be easily adjusted.

[0042] There are no particular restrictions on the density of the above-mentioned propylene resin, and it can be appropriately selected according to the purpose, but 0.89 g / cm³ is acceptable. 3 ~0.93g / cm 3 Preferably, 0.90 g / cm³ 3 ~0.92g / cm 3 This is preferable.

[0043] There are no particular restrictions on the melting point of the propylene resin mentioned above, and it can be appropriately selected depending on the purpose, but 110°C to 170°C is preferred, 121°C to 166°C is more preferred, and 121°C to 140°C is even more preferred.

[0044] (Layer structure of carrier film) The carrier film of the present invention includes at least a nylon layer. Specifically, examples of layer configurations include, but are not limited to, nylon layer / release layer, nylon layer / adhesive layer / release layer, surface layer / nylon layer / adhesive layer / release layer, and surface layer / adhesive layer / nylon layer / adhesive layer / release layer. In particular, from the viewpoint of achieving both the performance and film-forming properties of the carrier film, it is preferable that the surface layer, adhesive layer, nylon layer, adhesive layer, and release layer are laminated in that order (i.e., surface layer / adhesive layer / nylon layer / adhesive layer / release layer).

[0045] The carrier film of the present invention preferably has a total thickness of 22 to 150 μm, more preferably 40 to 100 μm, and even more preferably 50 to 100 μm. A total thickness within this range is preferable because it can be used as a carrier film for prepregs that are molded under strong tension.

[0046] From the viewpoint of peelability, the thickness of the above-mentioned peeling layer is preferably 2.0 μm to 20 μm, and more preferably 2.5 μm to 15 μm. The thickness of the adhesive layer described above is preferably 1 μm or more, and more preferably 3 μm or more, in order to ensure adhesion with the nylon layer. The thickness of the nylon layer is preferably 1 μm or more, and more preferably 2 μm or more, from the viewpoint of gas permeability. Furthermore, it is preferable that the thickness be 10 μm or less, as this makes it easier to make the carrier film a monomaterial. From the viewpoint of film formation properties, the thickness of the surface layer is preferably 10 μm to 100 μm, and more preferably 15 μm to 70 μm.

[0047] The thickness of the release layer is preferably in the range of 5 to 20% of the total thickness of the carrier film of the present invention, and more preferably in the range of 5 to 15%. When the ratio of the thickness of the release layer to the total thickness of the carrier film is within this range, good release properties and visibility are obtained. The thickness of the above-mentioned adhesive layer is preferably in the range of 5 to 20% of the total thickness of the carrier film of the present invention, more preferably 7 to 15%. If the ratio of the thickness of the adhesive layer to the total thickness of the carrier film is within this range, the peelability is improved. The thickness of the above-mentioned nylon layer is preferably in the range of 3 to 15% of the total thickness of the carrier film of the present invention, more preferably 5 to 10%, from the viewpoint of the balance between economy and gas permeability. The thickness of the above-mentioned surface layer is preferably 30 to 80% of the total thickness of the multilayer film of the present invention, more preferably 35 to 75%, from the viewpoint of the rigidity and handling properties of the film.

[0048] (Haze degree) The carrier film of the present invention preferably has a haze degree of 20% or more, more preferably 30% or more. When the haze degree is 20% or more, the visibility is high, and the risk of film residue during peeling can be suppressed. In addition, it becomes easier to detect film residue by a sensor or the like. The haze degree is a value measured using a haze meter (manufactured by Nippon Electric Shikou Co., Ltd.) based on JIS K 7105 (unit: %).

[0049] (Oxygen permeability) The carrier film of the present invention preferably has an oxygen permeability of 300 (ml / m 2 ·24h·atm) or less, more preferably 0.1 to 200 (ml / m 2 ·24h·atm), still more preferably 0.5 to 170 (ml / m 2 ·24h·atm), and particularly preferably 1 to 150 (ml / m 2 ·24h·atm). When the oxygen permeability is 300 (ml / m 2 ·24h·atm) or less, the progress of oxygen dissolution contained in the fiber reinforced composite material can be suppressed, the intrusion of oxygen in the air during storage of the fiber reinforced composite material can be suppressed, the action of oxygen as a polymerization inhibitor can be prevented, and the delay of the gel time after storage (stability of the gel time) can be suppressed, which is useful. The oxygen permeability of the carrier film shall be the value measured using the film and sheet gas permeability test method specified in JIS K 7126.

[0050] (rigidity) The carrier film of the present invention preferably has a rigidity of 180 MPa or more, more preferably 200 MPa or more, and even more preferably 210 MPa or more. The stiffness is determined based on ASTM D-882, by measuring the 1% tangential modulus (in MPa) at 23°C in the extrusion direction during film manufacturing using a Tensilon tensile testing machine (device name: RTC-1210A, manufactured by A&D Co., Ltd.), and evaluating the stiffness based on the aforementioned 1% tangential modulus. Note that "1% tangential modulus" refers to the tangential modulus of elasticity when a 1% strain is applied.

[0051] (Monomaterial film) Carrier films are intermediate materials used in the manufacture of molded products and are discarded after peeling, so recyclability is also important. The carrier film of the present invention is preferably a monomaterial film in which propylene resin accounts for 90% or more by mass of the components in the carrier film. With such a monomaterial film, even if the carrier film recovered during recycling is repelled, the deterioration of its performance can be kept to a minimum.

[0052] (Method of manufacturing carrier film) The method for manufacturing the carrier film of the present invention is not particularly limited, but for example, one method is co-extrusion, in which each resin or resin mixture used for the surface layer, adhesive layer, nylon layer, adhesive layer, and release layer is heated and melted in separate extruders, and then laminated in the order of surface layer / adhesive layer / nylon layer / adhesive layer / release layer in the molten state using methods such as co-extrusion multilayer die method or feed block method, and then formed into a film by inflation or T-die chill roll method. This co-extrusion method is preferred because it allows for relatively free adjustment of the thickness ratio of each layer, and a carrier film with excellent hygiene and cost performance can be obtained.

[0053] Furthermore, when laminating the above resin mixture into layers, the dry-blended resin mixture can be directly extruded using a co-extruder. Alternatively, the resin mixture can be pre-melted using a melt-mixing device such as a single-screw extruder, twin-screw extruder, or Bravender mixer, then pelletized and extruded using a co-extruder to form the layers.

[0054] Since the carrier film of the present invention is obtained as a substantially unstretched carrier film by the above manufacturing method, it is also advantageous for molding.

[0055] Furthermore, the peelability may be further improved by applying an embossed finish by bringing a roll with an uneven surface into contact with the extruded peel layer immediately after extrusion.

[0056] Furthermore, to improve the wettability of the fiber-impregnated resin, the above-mentioned release layer can be subjected to a surface treatment. Examples of such surface treatments include surface oxidation treatments such as corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment, or surface roughening treatments such as sandblasting, but corona treatment is preferred.

[0057] <Carrier film coated fiber-reinforced composite material> The carrier film-coated fiber-reinforced composite material of the present invention is preferably a carrier film-coated fiber-reinforced composite material in which a fiber-reinforced composite material having a radical polymerizable resin composition containing at least a radical polymerizable resin and a polymerization initiator, and a fiber substrate, is coated with the carrier film of the present invention. By coating both sides of the fiber-reinforced composite material having the radical polymerizable resin composition and the fiber substrate with the carrier film of the present invention, the delay in the progress of the curing reaction after storage at room temperature can be suppressed, the curing reaction can be carried out appropriately during the curing reaction (heating, pressurizing) of the fiber-reinforced composite material, the occurrence of molding defects is suppressed, and workability is excellent, which is preferable. Furthermore, the carrier film-coated fiber-reinforced composite material may be used in the manufacture of sheet molding compounds (SMC) or may be a prepreg.

[0058] (Radical polymerizable resin composition) The fiber-reinforced composite material of the present invention may have a radical polymerizable resin composition containing a radical polymerizable resin and a polymerization initiator. Using the radical polymerizable resin is preferable because it provides good strength and heat resistance. As the radical polymerizable resin, polymers having (meth)acryloyl groups or unsaturated polyester polymers can be used. Examples include epoxy (meth)acrylate, urethane-modified epoxy (meth)acrylate, and urethane (meth)acrylate. However, urethane-modified epoxy (meth)acrylate and urethane (meth)acrylate are preferred, and urethane (meth)acrylate is more preferred, as they provide better curability. These radical polymerizable resins can be used alone or in combination of two or more. Furthermore, polymerizable monomers may be added to the radical polymerizable resin composition to adjust the tackiness (surface stickiness).

[0059] The epoxy (meth)acrylate can be obtained by reacting an epoxy resin with (meth)acrylic acid and / or (meth)acrylic anhydride. An example of a method to achieve an average hydroxyl group count of 1.8 to 2.6 per molecule is to control it by setting the average epoxy group count and average hydroxyl group count of the epoxy resin, and the number of moles of (meth)acrylic acid and / or (meth)acrylic anhydride used in the reaction.

[0060] The epoxy resins include, for example, bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol fluorene type epoxy resin, biscresol fluorene type epoxy resin, novolac type epoxy resins such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, oxodoridone modified epoxy resin, and brominated epoxy resins of these resins, as well as polyhydric alcohol glycidyl ethers such as glycidyl ethers of phenols, dipropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether of alkylene oxide adducts of bisphenol A, and diglycidyl ether of hydrogenated bisphenol A. Examples include alicyclic epoxy resins such as 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate and 1-eposiethyl-3,4-epoxycyclohexane; glycidyl esters such as diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl-p-oxybenzoic acid and glycidyl dimer acid; glycidylamines such as tetraglycidyldiaminodiphenylmethane, tetraglycidyl-m-xylenediamine, triglycidyl-p-aminophenol and N,N-diglycidylaniline; and heterocyclic epoxy resins such as 1,3-diglycidyl-5,5-dimethylhydantoin and triglycidyl isocyanurate. Among these, bisphenol-type epoxy resin, novolac-type epoxy resin, or oxodoridone-modified epoxy resin are more preferred because they yield molded products with superior mechanical strength and heat resistance. Furthermore, bisphenol-type epoxy resin or oxodoridone-modified epoxy resin are even more preferred because they yield cured products with superior mechanical strength and other properties. The epoxy equivalent of the epoxy resin is preferably between 150 and 400 from the viewpoint of heat resistance and curability. These epoxy resins can be used individually or in combination of two or more types.

[0061] The reaction between the epoxy resin and (meth)acrylic acid described above is preferably carried out at 60 to 140°C using an esterification catalyst. Polymerization inhibitors and the like can also be used.

[0062] The urethane (meth)acrylate is preferably obtained by the reaction of a polyisocyanate, a polyol, and a hydroxyl group-containing (meth)acrylate.

[0063] The aforementioned polyisocyanates include, for example, 1,3-xylylene diisocyanate, 2,4-tole diisocyanate (TDI), 2,6-tole diisocyanate (TDI), tolidine diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), carbodiimide modified, nurate modified, biuret modified, urethaneimine modified, polyol modified with polyols having a number average molecular weight of 1,000 or less such as diethylene glycol or dipropylene glycol, aromatic isocyanate compounds such as polymethylene polyphenyl polyisocyanate and m-tetramethylxylylene diisocyanate, and hydrogenated xylylene Examples include alicyclic isocyanate compounds such as diisocyanate (1,3-bis(isocyanatomethyl)cyclohexane), isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, norbornene diisocyanate, dicyclohexylmethane diisocyanate, hydrogenated methylenebisphenyl diisocyanate, and 1,4-cyclohexane diisocyanate; aliphatic isocyanate compounds such as 1,6-hexamethylene diisocyanate, nurate-modified hexamethylene diisocyanate, biuret-modified hexamethylene diisocyanate, adduct-modified hexamethylene diisocyanate, trimethylene diisocyanate, and dimer acid diisocyanate; trifunctional isocyanates having an isocyanurate ring formed by the trimmerization of a bifunctional isocyanate compound; and commercially available polyol-modified isocyanate prepolymers. These isocyanate compounds can be used individually or in combination of two or more. From the viewpoint of weather resistance, storage stability, and heat resistance of molded products, alicyclic isocyanate compounds, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), and polymethylene polyphenyl polyisocyanate are preferred.

[0064] The polyisocyanate is preferably present in an amount of 20% by mass or more, and more preferably 50% by mass or more, in the isocyanate raw material of the urethane (meth)acrylate.

[0065] The polyol is not particularly limited, but can be aliphatic alcohol, cyclic aliphatic alcohol, etherified diphenol, polyester polyol, acrylic polyol, polyether polyol, polycarbonate polyol, polyalkylene polyol, etc. The polyol can be used alone or in combination of two or more types.

[0066] Examples of aliphatic alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,4-butenediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 2-ethyl-2-methylpropane-1,3-diol, 2-butyl-2-ethylpropane-1,3-diol, 1,6- Examples of suitable alcohols include hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,4-dimethyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol, triethylene glycol, dipropylene glycol, polypropylene glycol, and polyethylene glycol. Examples of cyclic aliphatic alcohols include hydrogenated bisphenol A, tricyclodecanedimethanol, and spiroglycol. Of these, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol are preferred from the viewpoint of resin viscosity and the mechanical properties of the cured product.

[0067] Examples of etherified diphenols include alkylene oxide adducts of bisphenol A and diols obtained by brominating alkylene oxide adducts of bisphenol A. The alkylene oxide can be ethylene oxide or propylene oxide, and it is preferable that the average number of added moles of the alkylene oxide is 2 to 16 moles per mole of bisphenol A.

[0068] Examples of polyester polyols include those obtained by polycondensation of unsaturated and / or saturated acids with the aforementioned aliphatic alcohols and etherified diphenols. Examples of unsaturated acids include maleic anhydride, maleic acid, and fumaric acid. Examples of saturated acids include phthalic acid, terephthalic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, succinic acid, sebacic acid, alkylsuccinic acid, alkenylsuccinic acid, itaconic acid, biphenyldicarboxylic acid, naphthalenedicarboxylic acid, 5-tert-butyl-1,3-benzenedicarboxylic acid and ester-forming derivatives thereof such as their acid anhydrides, lower alkyl esters, and acid halides. From the viewpoint of resin viscosity and the mechanical properties of the cured product, polyester polyols obtained by polycondensation of one or more selected from terephthalic acid, isophthalic acid, and their ester-forming derivatives with one or more selected from 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol are particularly preferred.

[0069] Examples of the hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxy-n-butyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-n-butyl (meth)acrylate, 3-hydroxy-n-butyl (meth)acrylate polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and diacrylated isocyanurate. However, 2-hydroxyethyl (meth)acrylate is preferred from the viewpoint of mechanical properties and viscosity of the cured product, and pentaerythritol tri(meth)acrylate is preferred from the viewpoint of heat resistance. These hydroxyl group-containing (meth)acrylates can be used individually or in combination of two or more.

[0070] The hydroxyl group-containing (meth)acrylate is preferably present in an amount of 5 to 50% by mass in the prepreg resin composition.

[0071] The molar ratio (NCO / OH) of the isocyanate group (NCO) of the isocyanate compound to the hydroxyl group (OH) of the compound having a hydroxyl group, which is used as a raw material for the urethane (meth)acrylate, is preferably 0.7 to 1.5, more preferably 0.8 to 1.3, and even more preferably 0.8 to 1.0.

[0072] The polymerization initiator contained in the radical resin composition is not particularly limited and includes, for example, organic peroxides, azo compounds, redox initiators, etc., among which organic peroxides are preferred from the viewpoint of stability at room temperature (23°C).

[0073] Examples of the organic peroxides include diacyl peroxide compounds, peroxyester compounds, hydroperoxide compounds, ketone peroxide compounds, alkyl perester compounds, parkerized compounds, and peroxyketals, which can be appropriately selected depending on the molding conditions and prepreg storage temperature. These polymerization initiators can be used individually or in combination of two or more.

[0074] Furthermore, among these organic peroxides, it is preferable that the temperature for obtaining a half-life of 10 hours is 70-100°C, as these have a long lifespan at room temperature for the prepreg and harden quickly upon heating. Examples of such organic peroxides include 1,6-bis(t-butylperoxycarbonyloxy)hexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-amylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, t-butylperoxydiethyl acetate, t-butylperoxyisopropyl carbonate, t-amylperoxyisopropyl carbonate, t-hexylperoxyisopropyl carbonate, di-tert-butylperoxyhexahydroterephthalate, t-amylperoxytrimethylhexanoate, and t-hexylperoxy-2-ethylhexanoate.

[0075] The content of the polymerization initiator is preferably in the range of 0.3 to 3% by mass relative to the total amount of resin components such as the radical polymerizable resin and the thermosetting resin described later, because it exhibits excellent curing properties and storage stability.

[0076] Furthermore, the radical resin composition may contain ethylenically unsaturated monomers, as this improves curability and other properties.

[0077] The ethylenically unsaturated monomer is preferably one that does not react with the isocyanate group at room temperature. Examples of ethylenically unsaturated monomers that do not react with the isocyanate group at room temperature include monofunctional (meth)acrylates, polyfunctional (meth)acrylates, and vinyl monomers.For example, vinyl monomers such as styrene, methylstyrene, halogenated styrene, divinylbenzene, vinyl acetate; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, Cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, methylbenzyl (meth)acrylate, phenoxyethyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, morpholine (meth)acrylate, phenylphenoxyethyl acrylate, phenylbenzyl (meth)acrylate, phenyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate Monofunctional (meth)acrylate compounds such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate; ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tripylene di(meth)acrylate, bisphosphonate Examples include polyfunctional (meth)acrylate compounds such as phenol di(meth)acrylate, ethylene oxide-added bisphenol A di(meth)acrylate, propylene oxide-added bisphenol A di(meth)acrylate, norbornene dimethanol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, 1,4-cyclohexanedimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tris(2-(meth)acryloyloxyethyl) isocyanurate. These can be used individually or in combination of two or more.

[0078] Among these ethylenically unsaturated monomers, monofunctional (meth)acrylates with a molecular weight of 100 to 350 and a cyclic structure are preferred due to the odor and handling of hazardous materials in the work environment, as well as the mechanical strength and heat resistance of the molded product. Phenoxyethyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, benzyl (meth)acrylate, methylbenzyl (meth)acrylate, isobornyl (meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, and styrene are more preferred, and phenoxyethyl (meth)acrylate and benzyl (meth)acrylate are even more preferred.

[0079] In addition to the radical polymerizable resin and polymerization initiator, the radical polymerizable resin composition may also contain other components, such as resin components other than the radical polymerizable resin, such as thermosetting resins and thermoplastic resins, polymerization inhibitors, curing accelerators, fillers, low shrinkage agents, mold release agents, thickeners, devising agents, pigments, antioxidants, plasticizers, flame retardants, antibacterial agents, ultraviolet stabilizers, reinforcing materials, and photocuring agents.

[0080] Examples of the thermosetting resins include vinyl ester resins, vinyl urethane resins, unsaturated polyester resins, phenolic resins, melamine resins, and furan resins. These thermosetting resins can be used individually or in combination of two or more types.

[0081] Examples of the thermoplastic resins include polyamide resins, polyethylene terephthalate resins, polybutylene terephthalate resins, polycarbonate resins, urethane resins, polypropylene resins, polyethylene resins, polystyrene resins, acrylic resins, polybutadiene resins, polyisoprene resins, and those modified by copolymerization or other means. These thermoplastic resins can be used individually or in combination of two or more types.

[0082] Examples of polymerization inhibitors include hydroquinone, trimethylhydroquinone, pt-butylcatechol, t-butylhydroquinone, toluhydroquinone, p-benzoquinone, naphthoquinone, hydroquinone monomethyl ether, phenothiazine, copper naphthenate, and copper chloride. These polymerization inhibitors can be used individually or in combination of two or more.

[0083] Examples of the curing accelerators include metal soaps such as cobalt naphthenate, cobalt octenoate, vanadyl octenoate, copper naphthenate, and barium naphthenate, as well as metal chelate compounds such as vanadyl acetyl acetate, cobalt acetyl acetate, and iron acetylacetonate. Examples of amines include N,N-dimethylamino-p-benzaldehyde, N,N-dimethylaniline, N,N-diethylaniline, N,N-dimethyl-p-toluidine, N-ethyl-m-toluidine, triethanolamine, m-toluidine, diethylenetriamine, pyridine, phenylmorpholine, piperidine, and diethanolaniline. Examples of urethane reaction accelerators include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, and stannous octoate. These curing accelerators can be used individually or in combination of two or more.

[0084] The aforementioned fillers include inorganic compounds and organic compounds, and can be used to adjust the physical properties of molded products, such as strength, elastic modulus, impact strength, and fatigue durability.

[0085] Examples of the inorganic compounds include calcium carbonate, magnesium carbonate, barium sulfate, mica, talc, kaolin, clay, Celite, asbestos, Perlite, baryta, silica, silica sand, dolomite limestone, gypsum, aluminum powder, hollow balloons, alumina, glass powder, aluminum hydroxide, granite, zirconium oxide, antimony trioxide, titanium oxide, molybdenum dioxide, iron powder, and the like.

[0086] The aforementioned organic compounds include natural polysaccharide powders such as cellulose and chitin, and synthetic resin powders. The synthetic resin powders can include powders of organic materials composed of hard resins, soft rubbers, elastomers, or polymers (copolymers), or particles having a multilayer structure such as a core-shell type. Specifically, examples include particles made of butadiene rubber and / or acrylic rubber, urethane rubber, silicone rubber, polyimide resin powder, fluororesin powder, and phenolic resin powder. These fillers can be used individually or in combination of two or more types.

[0087] Examples of the mold release agent include zinc stearate, calcium stearate, paraffin wax, polyethylene wax, and carnauba wax. Preferably, paraffin wax, polyethylene wax, and carnauba wax are used. These mold release agents can be used individually or in combination of two or more.

[0088] Examples of the thickening agents include metal oxides and metal hydroxides such as magnesium oxide, magnesium hydroxide, calcium oxide, and calcium hydroxide, as well as acrylic resin-based fine particles, which can be appropriately selected depending on the handling requirements of the fiber-reinforced composite material of the present invention. These thickening agents can be used individually or in combination of two or more types.

[0089] (Thermosetting resin-based fiber-reinforced composite material) The fiber-reinforced composite material of the present invention may be a fiber-reinforced composite material comprising a thermosetting resin composition containing a thermosetting resin and a fiber base material. By coating both sides of the fiber-reinforced composite material comprising the thermosetting resin composition and the fiber base material with the carrier film of the present invention, it can be used for refrigerated storage or room temperature storage and offers excellent workability.

[0090] (thermosetting resin) Thermosetting resins include epoxy resins, phenolic resins, unsaturated imide resins, maleimide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, melamine resins, etc., but are not limited to these, and known thermosetting resins can also be used. These resins can be used individually or in combination. From the viewpoint of moldability and electrical insulation, epoxy resins and maleimide resins are preferred, and using both in combination is also preferred.

[0091] Examples of epoxy resins include novolac-type epoxy resins of the cresol novolac type, phenol novolac type, naphthol novolac type, aralkyl novolac type, and biphenyl novolac type; bisphenol-type epoxy resins of the bisphenol A type, bisphenol F type, bisphenol S type, bisphenol T type, and bisphenol Z type; halogenated bisphenol-type epoxy resins of the tetrabromobisphenol A type; biphenyl-type epoxy resins of the biphenyl type, tetramethylbiphenyl type, triphenyl type, and tetraphenyl type; naphthol aralkyl-type epoxy resins of the naphthol aralkyl type and naphthalenediol aralkyl type; fluorene-type epoxy resins; types with a dicyclopentadiene skeleton; types with an ethylenically unsaturated group in the skeleton; and alicyclic-type special structure epoxy resins. Furthermore, phosphorus-containing epoxy resins obtained by introducing phosphorus compounds into these epoxy resins can also be used. From the viewpoint of flame retardancy, halogenated epoxy resins may be used. Epoxy resins can be used individually, but multiple resins may be used in combination from the viewpoint of insulation reliability and heat resistance.

[0092] Both unmodified and modified maleimide resins can be used as maleimide resins. Examples of modified maleimide resins include those reacted with monoamine compounds such as p-aminophenol, those reacted with diamine compounds such as p-phenylenediamine, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminobiphenyl, and 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, or those reacted with monoamine compounds and diamine compounds.

[0093] Examples of maleimide resins include aliphatic hydrocarbon group-containing maleimides such as N,N'-ethylenebismaleimide, N,N'-hexamethylenebismaleimide, bis(4-maleimidocyclohexyl)methane, and 1,4-bis(maleimidomethyl)cyclohexane. Other examples of aromatic hydrocarbon group-containing maleimides include N,N'-(1,3-phenylene)bismaleimide, N,N'-[1,3-(2-methylphenylene)]bismaleimide, N,N'-[1,3-(4-methylphenylene)]bismaleimide, N,N'-(1,4-phenylene)bismaleimide, bis(4-maleimidophenyl)methane, bis(3-methyl-4-maleimidophenyl)methane, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)ketone, 1,3-bis(4-maleimidophenoxy)benzene, and bis[4-(4-maleimidophenoxy)phenyl]methane. These may be used individually or in combination. From the viewpoint of solubility in organic solvents, maleimide resins having phenoxy groups are preferred, and from the viewpoint of reactivity and heat resistance, bis(4-maleimidophenyl)methane and 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane are more preferred.

[0094] (Modified silicone oil) By using a flexible, low-elasticity modified silicone oil in combination with a rigid, high-elasticity thermosetting resin, a phase-separated structure (sea-island structure) having high-elasticity and low-elasticity parts can be formed. This is preferable because it relieves stress, contributes to a lower coefficient of thermal expansion, and suppresses warping. One type of modified silicone oil may be used alone, or two or more types may be used in combination. Modified silicone oil is a material that has a linear siloxane skeleton and contains groups other than hydrogen and hydrocarbon groups. Commercially available modified silicone oils can be used, and those with a dimethyl silicone skeleton are particularly preferred. Furthermore, those with reactive groups that can react with thermosetting resins are especially preferred. Reactive groups may be introduced into the side chains or terminals of the polysiloxane, and examples include epoxy groups, amino groups, hydroxyl groups, methacrylic groups, mercapto groups, carboxyl groups, alkoxy groups, and silanol groups. From the viewpoint of reactivity, modified silicone oils at both ends are preferred, and from the viewpoint of compatibility, those with a functional group equivalent of 5,000 or less are more preferred.

[0095] Examples of curing agents for epoxy resins include phenolic curing agents, cyanate ester curing agents, acid anhydride curing agents, and amine curing agents. If the thermosetting resin is a resin other than epoxy resin, known curing agents for that thermosetting resin can be used. The curing agent may be used alone or in combination of two or more types. Examples of phenolic curing agents include cresol novolac type curing agents, biphenyl type curing agents, and phenol novolac type curing agents. Examples of cyanate ester curing agents include bisphenol A dicyanate, 4,4'-methylenebis(2,6-dimethylphenyl cyanate), and hexafluorobisphenol A dicyanate. Examples of acid anhydride curing agents include phthalic anhydride, trimellitic anhydride, and pyromellitic anhydride. Examples of amine curing agents include metaphenylenediamine, 4,4'-diaminodiphenylmethane, and triethylenetetramine. In addition, urea resin and the like can also be used as curing agents.

[0096] The thermosetting resin composition may also contain other components, such as thermoplastic resins, polymerization inhibitors, curing accelerators, fillers, low-shrinkage agents, mold release agents, thickeners, devisers, pigments, antioxidants, plasticizers, flame retardants, antibacterial agents, UV stabilizers, reinforcing materials, and photocuring agents. Specific examples and preferred ranges are the same as those described above.

[0097] (Fiber base material) The fiber-reinforced composite material comprises the above-mentioned radical polymerizable resin composition and / or the above-mentioned thermosetting resin composition and a fiber substrate. Examples of the aforementioned fiber base material (sometimes also called reinforcing fiber) include carbon fiber, glass fiber, silicon carbide fiber, alumina fiber, boron fiber, metal fiber, aramid fiber, vinylon fiber, polyester fiber, basalt fiber, BPO fiber, PPS fiber, and organic fibers such as cellulose. However, carbon fiber or glass fiber is preferred, and carbon fiber is more preferred, as it yields molded products with higher strength and elasticity. These fiber base materials can be used individually or in combination of two or more types.

[0098] Various types of carbon fibers can be used, such as polyacrylonitrile-based, pitch-based, and rayon-based fibers. Among these, polyacrylonitrile-based fibers are preferred because they allow for easy acquisition of high-strength carbon fibers.

[0099] There are no particular restrictions on the shape of the fiber substrate, but examples include reinforced fiber tows formed by converging reinforcing fiber filaments, unidirectional materials formed by aligning reinforcing fiber tows in one direction, woven fabrics, or nonwoven fabrics made of short-cut reinforcing fibers. However, it is preferable to use unidirectional materials as reinforcing fibers and laminate and mold them to obtain high mechanical properties. Furthermore, there are no particular restrictions on the surface treatment agent for the fiber substrate.

[0100] Examples of the aforementioned woven fabrics include plain weave, twill weave, satin weave, or non-crimped fabrics, such as stitched sheets made by stitching together sheets of fiber bundles aligned in one direction or sheets layered at different angles to prevent them from unraveling.

[0101] The basis weight (fiber 1m) of the aforementioned fiber base material (reinforcement fiber) 2 There are no particular restrictions on the weight per square meter, but for example, 10-650 g / m 2 Preferably, 50-500 g / m 2 More preferably, 50-300 g / m 2 This is even more preferable. 10g / m 2 This weight is preferable because it results in less variation in fiber width and better mechanical properties. 650g / m 2 The following weights are preferable because they allow for good resin impregnation.

[0102] (Prepreg) The fiber-reinforced composite material of the present invention is preferably a prepreg. By reacting the prepreg with the radical polymerizable resin composition, an uncured or semi-cured state called a prepreg can be formed. After the product is distributed in the prepreg state, final curing may be performed to form a cured product (molded article). Furthermore, when forming a laminate using the prepreg, a laminate in which each layer is tightly bonded can be formed by laminating the prepreg and other layers after production and then performing final curing. The prepreg can be a thermosetting prepreg or an electron beam curable prepreg, but from the viewpoint of workability and cost, a thermosetting prepreg is preferred.

[0103] The fiber base material content in the above prepreg is preferably 30% by mass or more, more preferably 35 to 80% by mass, and even more preferably 40 to 70% by mass. By increasing the content to 30% by mass or more, the mechanical strength of the resulting molded product is further improved. In this invention, "fiber base material content in the prepreg" refers to the proportion of fiber base material in the total mass of fiber base material and resin composition in the prepreg after the films covering both sides have been peeled off.

[0104] The method for manufacturing the above prepreg is not particularly limited and can be manufactured by conventionally known methods, such as the wet method, hot melt method, and hand lay-up method. In the case of the hand lay-up method, a radical polymerizable resin composition (resin solution) is prepared by mixing a radical polymerizable resin and a polymerization initiator using a known mixer such as a planetary mixer or kneader, and then preparing the solution with an oxygen permeability of 200 ml / m³. 2 After coating a film with an oxygen permeability of 24h·atm or less using a doctor knife, flow coater, etc. (preferably to a thickness of 10-650 μm), the fiber substrate is impregnated by the hand lay-up method, and then the oxygen permeability from the top surface is 200 ml / m². 2 The raw materials are sandwiched (covered) with a film with a temperature of 24 hours (atm) or less, and then heated at room temperature (23°C) to 70°C for 5 minutes to 48 hours to age and react, thereby obtaining a prepreg.

[0105] The thickness of the prepreg is preferably 500 μm or less, more preferably 20 to 500 μm, even more preferably 50 to 400 μm, and particularly preferably 100 to 300 μm. A thickness of 500 μm or less allows for good resin impregnation, while a thickness of 20 μm or more facilitates handling when laminating the prepreg, which is preferable.

[0106] The aforementioned prepreg is preferably a thermosetting prepreg, as this improves productivity and handling. Therefore, the gel time at 140°C is preferably in the range of 10 to 90 seconds, and more preferably in the range of 15 to 60 seconds. The gel time of the prepreg in this invention was measured by a method compliant with the curing characteristics test specified in JASOM406-87.

[0107] <Molded products> The molded article of the present invention uses a carrier film-coated fiber-reinforced composite material, and is preferably a cured product of the fiber-reinforced composite material. The obtained molded article is formed from a fiber substrate and a radical polymerizable resin composition, and is used after peeling off the carrier film that coats both sides of the fiber-reinforced composite material. There are no particular limitations on the method for obtaining a molded product from the prepreg obtained above, and it can be manufactured by conventionally known methods. For example, a method is used in which the film is peeled off from both sides of the prepreg, 8 to 16 layers of prepreg are stacked, then placed in a mold preheated to 110 to 160°C, the mold is clamped in a compression molding machine to form the prepreg, the prepreg is hardened by maintaining a molding pressure of 0.1 MPa to 10 MPa, and then the molded product is removed to obtain the molded product. In this case, a manufacturing method is preferred in which the product is heated and compressed in a mold having a shear edge, at a mold temperature of 120 to 160°C, and a molding pressure of 1 MPa to 8 MPa is maintained for a specified time of 1 to 4 minutes per 1 mm of thickness of the molded product. [Examples]

[0108] The present invention will be described in more detail below with reference to specific examples, but the present invention is not limited to these examples.

[0109] (Preparation of resin composition (1) for prepreg) A prepreg resin composition (1) was obtained by mixing 50 parts by mass of a mixture of polymethylene polyphenyl polyisocyanate and 4,4'-diphenylmethane diisocyanate (MDI) ("Millionate MR-200" manufactured by Tosoh Corporation), 50 parts by mass of 4,4'-diphenylmethane diisocyanate (MDI), 66 parts by mass of 2-hydroxyethyl methacrylate (HEMA), 25 parts by mass of Nieuport BPE-20 (manufactured by Sanyo Chemical Industries, Ltd.: EO adduct of bisphenol A, hydroxyl group equivalent: 164 g / eq), 31 parts by mass of Nieuport BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.: EO adduct of bisphenol A, hydroxyl group equivalent: 204 g / eq), and 3 parts by mass of a polymerization initiator ("Trigonox 122-C80" manufactured by Kayaku Akzo Co., Ltd., organic peroxide).

[0110] (Example 1) The resins and resin mixtures forming each of the layers—the surface layer, adhesive layer (D1), nylon layer, adhesive layer (D2), and release layer—were prepared using the following resins, respectively. Surface layer: Polypropylene (MFR 7.0g / 10 minutes (230℃, load 2.16kg), density 0.90g / cm³) 3 (Melting point 164℃) 100 parts. Adhesive layers (D1), (D2): Modified polypropylene (MFR 6.0g / 10 minutes (230℃, load 2.16kg), density 0.89g / cm³) 3 (Melting point 140℃) Nylon layer: 100 parts of nylon 6 (relative viscosity (96% sulfuric acid) 3.33, melting point 220°C) (hereinafter referred to as NY6). Release layer: Propylene-ethylene block copolymer (MFR 8.0g / 10 min (230℃, load 2.16kg), density 0.90g / cm³) 3 100 copies of BCOPP(1) (melting point 166°C) (hereinafter referred to as BCOPP(1)).

[0111] The resins and resin mixtures forming each layer were supplied to three extruders, and the laminated film, consisting of a surface layer, adhesive layer (D1), nylon layer, adhesive layer (D2), and release layer, was co-extruded from a T-die at an extrusion temperature of 250°C, with the ratio of the average thickness of each layer being 60%:9%:7%:9%:15%. The film was then cooled with a water-cooled metal cooling roll at 40°C to form the fiber-reinforced composite material carrier film of Example 1, which had a total thickness of 50 μm.

[0112] <<Measurement of oxygen permeability>> The oxygen permeability of the fiber-reinforced composite material carrier film obtained in Example 1 was measured using a MOCON oxygen permeability measuring device OX-TRAN2 / 12 (manufactured by Hitachi High-Tech Corporation) in accordance with JIS K 7126 (unit: ml / m³). 2 (24-hour ATM).

[0113] <<Measuring Stiffness>> For the fiber-reinforced composite material molding carrier film obtained in Example 1, the 1% tangential modulus (unit: MPa) at 23°C in the extrusion direction during film manufacturing was measured using a Tensilon tensile testing machine (device name: RTC-1210A, manufactured by A&D Co., Ltd.) in accordance with ASTMD-882. The stiffness was evaluated based on the aforementioned 1% tangential modulus. Note that "1% tangential modulus" refers to the tangential modulus of elasticity when a 1% strain is applied.

[0114] <<Measurement of cloudiness>> The degree of cloudiness of the obtained fiber-reinforced composite material carrier film of Example 1 was measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd.) in accordance with JIS K 7105 (unit: %).

[0115] (Prepreg preparation) The resin composition for prepreg (1) was applied to the release surface of the carrier film for molding fiber-reinforced composite material of Example 1. Then, carbon fibers (FOMOSA TAFFETA "EC3C") were impregnated using a hand lay-up method to achieve a carbon fiber content of 50% by mass. The same film was then covered on the opposite side, and prepreg (1) was prepared by aging at 45°C for 24 hours. The molar ratio (NCO / OH) of the raw materials excluding carbon fibers in this prepreg (1) was 0.94. The thickness of the obtained prepreg was 0.25 mm (250 μm).

[0116] <<Manufacturing of molded products>> The prepregs obtained in the above examples and comparative examples had their films peeled off from both sides. Twelve of these prepregs were stacked, and a molded product was obtained by heating and pressurizing them for 3 minutes using a 200 mm x 100 mm mold at a mold temperature of 145°C and a mold closing pressure of 4 MPa.

[0117] <<Evaluation of Visibility>> The L* values ​​of the carrier film-coated prepregs and the peeled prepregs obtained in the above examples and comparative examples were measured using a colorimeter (ZE6000, manufactured by Nippon Denshoku Industries Ltd.) by reflectance measurement with a D65 light source. The L* value of the peeled prepreg was subtracted from the L* value of the carrier film-coated prepreg and evaluated according to the following evaluation criteria. Note that a higher L* value indicates brighter light, and a larger difference in L* values ​​indicates better visibility. ○: The difference in L* values ​​is 8 or more. △: The difference in L* values ​​is between 5 and 8. ×: The difference in L* values ​​is less than 5.

[0118] <<Evaluation of Peelability>> The ease of peeling the film off both sides of the carrier film-coated prepreg obtained in the above examples and comparative examples was evaluated. ○: Easy to peel off ×: Difficult to peel off, or film residue remains.

[0119] <<Evaluation of gel time stability>> The gel time (140°C) of the prepreg obtained by peeling the film from both sides was measured immediately after manufacturing and two months later, using a method compliant with the curing characteristics test specified in JASO M 406-87. The evaluation sample was stored at room temperature (23°C, 55% RH) from immediately after manufacturing, and 24 samples cut to 5cm x 5cm were stacked to form the evaluation sample, and the gel time (seconds) was measured using the stacked prepreg. Gel time difference (seconds) = [(Gel time after 2 months) - (Gel time immediately after aging)] The evaluation was conducted as follows: ○: Gel time difference is less than 15 seconds △: Gel time difference is less than 20 seconds (practical level) ×: Gel time difference exceeds 20 seconds

[0120] <<Evaluation of moldability>> The surface of the molded product obtained above was visually evaluated according to the following criteria. ○: No swelling or uncured areas. ×: Blisters and / or uncured areas present.

[0121] The evaluation results of the prepregs obtained above, and the molded articles obtained using the prepregs, along with the physical properties of the carrier film, are shown in Table 1.

[0122] (Example 2) In Example 1, as shown in Table 1, 80 parts of BCOPP and ethylene-1-butene copolymer (MFR 4.0 g / 10 min (190°C, load 2.16 kg), density 0.90 g / cm³) were added to the release layer. 3 Except for changing the mixture to 20 parts of (melting point 58°C) (hereinafter referred to as EBR), a carrier film for molding fiber-reinforced composite materials of Example 2 was prepared in the same manner as in Example 1, and evaluated. The results are shown in Table 1.

[0123] (Example 3) In Example 1, the carrier film for molding fiber-reinforced composite materials of Example 3 was prepared and evaluated in the same manner as in Example 1, except that the total thickness of the carrier film was changed to 30 μm, as shown in Table 1. The results are shown in Table 1.

[0124] (Comparative Example 1) In Example 1, as shown in Table 1, adhesive layers (D1) and (D2) were not provided, and the release layer was made of propylene-ethylene random copolymer (MFR 7.5g / 10min (230℃, load 2.16kg), density 0.90g / cm³). 3 A carrier film for molding fiber-reinforced composite materials for Comparative Example 1 was prepared in the same manner as in Example 1, except that the amount of COPP (melting point 136°C) (hereinafter referred to as COPP) was changed to 100 parts, an intermediate layer consisting of 100 parts by mass of COPP was provided instead of the nylon layer, and the ratio of the average thickness of each layer of the laminated film formed by the surface layer / intermediate layer / release layer was changed to 40%:43%:17%, and the product was evaluated. The results are shown in Table 1.

[0125] (Comparative Example 2) In Comparative Example 1, as shown in Table 1, the surface layer was changed to 100 parts HOPP, and the ratio of the average thickness of each layer of the laminated film formed by the surface layer / intermediate layer / release layer was changed to 40%:25%:35%. Except for these changes, the carrier film for molding fiber-reinforced composite materials for Comparative Example 2 was prepared and evaluated in the same manner as in Comparative Example 1. The results are shown in Table 1.

[0126] [Table 1]

[0127] As shown in Table 1 above, the prepregs using the carrier films of Examples 1-3 exhibited excellent gel time stability and were less prone to molding defects. Furthermore, they had excellent release properties, making them useful as carrier films. In addition, they had a suitable degree of cloudiness, resulting in good visibility and making it easy to identify any remaining unreleased material.

[0128] On the other hand, in Comparative Examples 1 and 2, the oxygen permeability of the carrier film was high, resulting in a longer gel time difference, poor gel time stability, and inferior moldability.

Claims

1. A carrier film for molding fiber-reinforced composite materials, The carrier film includes at least a nylon layer, The carrier film comprises at least a propylene block copolymer and an acid-modified polyolefin. Carrier film for molding fiber-reinforced composite materials.

2. The carrier film further comprises a release layer and an adhesive layer, The release layer comprises at least a propylene block copolymer, The adhesive layer comprises at least an acid-modified polyolefin. A carrier film for molding fiber-reinforced composite materials according to claim 1.

3. The carrier film further includes a surface layer, The carrier film for molding fiber-reinforced composite materials according to claim 2, wherein the surface layer comprises at least a propylene homopolymer.

4. The carrier film for molding fiber-reinforced composite materials according to claim 3, wherein the carrier film for molding fiber-reinforced composite materials is laminated in the order of the surface layer, the adhesive layer, the nylon layer, the adhesive layer, and the release layer.

5. A carrier film for molding fiber-reinforced composite materials according to claim 1, wherein the total thickness is 22 to 150 μm.

6. A carrier film for molding fiber-reinforced composite materials according to claim 1, wherein the degree of cloudiness is 20% or more.

7. A carrier film-coated fiber-reinforced composite material, wherein a fiber-reinforced composite material having a radical polymerizable resin composition containing at least a radical polymerizable resin and a polymerization initiator, and a fiber substrate, is coated with a carrier film for molding fiber-reinforced composite materials according to any one of claims 1 to 6.

8. A molded article using the carrier film-coated fiber-reinforced composite material according to claim 7.

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