JP2016150981A - Base material for fiber-reinforced plastic molding and fiber-reinforced plastic molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently improve flame retardancy of a fiber-reinforced plastic molding comprising a combustible resin with a low limiting oxygen index.SOLUTION: A base material for fiber-reinforced plastic molding comprises a reinforced fiber, a thermoplastic resin, and an acrylic polymer, where the thermoplastic resin comprises a first resin with a limiting oxygen index of 30 or more and a second resin with a limiting oxygen index of 27 or less.SELECTED DRAWING: None

Description

  The present invention relates to a substrate for a fiber-reinforced plastic molded body and a fiber-reinforced plastic molded body. Specifically, the present invention relates to a fiber reinforced plastic molded body containing reinforcing fiber, a thermoplastic resin, and an acrylic polymer, and molding a fiber reinforced plastic molded body having improved flame retardancy. The present invention relates to a substrate for a fiber-reinforced plastic molded body to be obtained.

  Fiber reinforced plastic molded products molded from non-woven fabrics (also referred to as fiber reinforced plastic molded base materials) containing reinforced fibers such as carbon fibers and glass fibers have already been used in a variety of sports, leisure goods, aircraft materials, electronic equipment members, etc. Used in various fields. Thermosetting resins such as epoxy resins, unsaturated polyester resins, and phenolic resins are often used as the matrix resin in the fiber reinforced plastic molded body. However, when a thermosetting resin is used, the nonwoven fabric in which the thermosetting resin and the reinforcing fiber are mixed must be refrigerated and cannot be stored for a long time.

  For this reason, in recent years, development of a nonwoven fabric using a thermoplastic resin as a matrix resin and containing reinforcing fibers has been advanced. A nonwoven fabric using such a thermoplastic resin as a matrix resin has the advantage that it can be stored and managed for a long time. In addition, a nonwoven fabric containing a thermoplastic resin is easier to mold than a nonwoven fabric containing a thermosetting resin, and has the advantage that a molded product can be molded by performing heat and pressure treatment. ing. Furthermore, a fiber-reinforced plastic molded body molded from a nonwoven fabric containing a thermoplastic resin can be subjected to outsert molding as a post-process.

  The fiber reinforced plastic molded body may be required to have flame retardancy depending on its application. In particular, when a fiber-reinforced plastic molded body is incorporated in an electronic device or the like, flame retardancy is an essential condition. As a method for making a fiber reinforced plastic molded product flame retardant, a method of adding a flame retardant to a nonwoven fabric or a matrix resin is known (for example, Patent Documents 1 and 2). In addition, in order to enhance flame retardancy, it has been studied to use a thermoplastic resin having a high critical oxygen index. For example, use of a super engineering plastic resin such as polyetherimide (PEI) as a thermoplastic resin has been studied (Patent Document 3).

JP-A-9-278914 Japanese Patent Laid-Open No. 11-147965 Japanese Patent Laid-Open No. 3-180588

  As described above, it has been studied to increase the flame retardancy of a fiber-reinforced plastic molded body. However, when a large amount of a halogen-based flame retardant is used in order to enhance the flame retardancy, there is a problem that it may adversely affect the environment. Further, when a large amount of non-halogen flame retardant is used, there is a problem that it is difficult to reduce the thickness of the fiber-reinforced plastic molded body, and it is difficult to reduce the weight of the fiber-reinforced plastic molded body.

  In addition, in order to enhance the flame retardancy, it has been studied to use a super engineering plastic resin having a high critical oxygen index. However, depending on the application, production method, etc., there are cases where a super engineering plastic resin must be mixed with a flammable resin having a low critical oxygen index. For example, in order to ensure adhesion with other members, the same components as other members must be mixed, or binder components must be added to increase the production efficiency while maintaining sufficient strength of the nonwoven fabric before molding. There are cases where this is not possible. In such a case, the fiber reinforced plastic molded article is not sufficiently flame-retardant, and further improvement has been demanded.

  Therefore, in order to solve such problems of the prior art, the present inventors have studied for the purpose of sufficiently increasing the flame retardancy even in a fiber reinforced plastic molded article containing a flammable resin having a low critical oxygen index. Advanced.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that fiber-reinforced plastics can be used as thermoplastic resins even when not only super engineering plastic resins but also resins having a low critical oxygen index are used in combination. It has been found that the flame retardancy of a fiber-reinforced plastic molded article can be sufficiently enhanced by including an acrylic polymer in the molded article substrate.
Specifically, the present invention has the following configuration.

[1] A reinforcing fiber, a thermoplastic resin, and an acrylic polymer are included, and the thermoplastic resin includes a first resin having a limiting oxygen index of 30 or more and a second resin having a limiting oxygen index of 27 or less. A substrate for a fiber-reinforced plastic molded article characterized by
[2] The fiber-reinforced plastic molded article substrate according to [1], wherein the acrylic polymer is an acrylic fiber.
[3] The fiber-reinforced plastic molded article substrate according to [1] or [2], wherein the acrylic polymer includes an acrylonitrile unit.
[4] The fiber-reinforced plastic molded article substrate according to any one of [1] to [3], wherein the acrylic polymer is an acrylic pulp containing an acrylonitrile unit and a (meth) acrylate unit.
[5] The fiber-reinforced plastic according to any one of [1] to [4], wherein the content of the acrylic polymer is 0.5 to 20% by mass with respect to the total mass of the substrate for fiber-reinforced plastic molded body. Base material for molded bodies.
[6] The substrate for fiber-reinforced plastic molded body according to any one of [1] to [5], wherein the reinforcing fiber is a carbon fiber.
[7] The fiber-reinforced plastic molded body according to any one of [1] to [6], wherein the content of the reinforcing fiber is 30 to 70% by mass with respect to the total mass of the base material for the fiber-reinforced plastic molded body. Substrate for use.
[8] The substrate for fiber-reinforced plastic molded bodies according to any one of [1] to [7], further including a binder component.
[9] A fiber including a reinforcing fiber, a thermoplastic resin, and an acrylic polymer, and the thermoplastic resin includes a first resin having a limiting oxygen index of 30 or more and a second resin having a limiting oxygen index of 27 or less. Reinforced plastic molding.
[10] The fiber-reinforced plastic molded article according to [9], wherein the acrylic polymer includes an acrylonitrile unit.
[11] The fiber-reinforced plastic molded article according to [9] or [10], wherein the acrylic polymer includes an acrylonitrile unit and a (meth) acrylate unit.
[12] The fiber-reinforced plastic molded article according to any one of [9] to [11], having a thickness of 1 mm or less.
[13] The fiber-reinforced plastic molded body according to any one of [9] to [12], having a thickness of 0.5 mm or less.
[14] The fiber-reinforced plastic molded body includes a first layer and a second layer, the first layer includes a reinforced fiber and a first resin, and the second layer includes a reinforced fiber and a first resin. And the second resin, and the first layer includes the second resin, the content ratio of the second resin included in the second layer is that of the second resin included in the first layer. The fiber-reinforced plastic molded article according to any one of [9] to [13], which is higher than the content.

  According to the present invention, even in a fiber reinforced plastic molded article containing a combustible resin having a low critical oxygen index, the flame retardancy can be sufficiently enhanced. According to the present invention, the flame retardancy of the fiber-reinforced plastic molded article can be increased without using a large amount of flame retardant, and the burden on the environment can be reduced. Moreover, a thin and lightweight fiber-reinforced plastic molded body can be molded.

  Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

(Substrate for fiber reinforced plastic molding)
The present invention relates to a base material for a fiber-reinforced plastic molded body containing a reinforcing fiber, a thermoplastic resin, and an acrylic polymer. The thermoplastic resin used for the base material for a fiber-reinforced plastic molded body of the present invention includes a first resin having a limiting oxygen index of 30 or more and a second resin having a limiting oxygen index of 27 or less.

As described above, the base material for a fiber-reinforced plastic molded body of the present invention contains an acrylic polymer. For this reason, although the base material for fiber-reinforced plastic molded articles of the present invention contains the second resin having a low critical oxygen index, it is possible to mold a fiber-reinforced plastic molded article having excellent flame retardancy. . The limiting oxygen index of an acrylic polymer is 20 or less, and is considered to be an element that lowers the flame retardancy. However, the present invention has surprisingly succeeded in increasing flame retardancy by mixing an acrylic polymer with a substrate for a fiber-reinforced plastic molded body.
Furthermore, in the present invention, since a fiber-reinforced plastic molded article having high flame retardancy can be molded without adding a large amount of flame retardant, the fiber-reinforced plastic molded article can be thinned. In the present invention, even in a thin fiber-reinforced plastic molded product, the flame retardancy can be sufficiently enhanced.

  JAPAN TAPPI PAPER PULSE TEST METHOD NO. The air permeability defined in 5-2 is preferably 250 seconds or less, more preferably 230 seconds or less, and even more preferably 200 seconds or less. This numerical value indicates that the smaller the number, the easier air can pass through (the better the air permeability). In the present invention, by setting the air permeability of the base material for fiber-reinforced plastic molded body within the above range, the molding speed in the heating and pressing step can be increased, and the production efficiency can be increased.

(Acrylic polymer)
The base material for fiber-reinforced plastic molded bodies of the present invention contains an acrylic polymer. The acrylic polymer used in the present invention may be an acrylic fiber, an emulsion containing an acrylic polymer, or a solution in which an acrylic polymer is dispersed in water.

Among these, the acrylic polymer is preferably an acrylic fiber. The acrylic fiber preferably contains an acrylonitrile unit. In particular, the acrylic fiber is preferably an acrylic pulp containing an acrylonitrile unit and a (meth) acrylate unit. Here, the “unit” is a repeating unit (monomer unit) constituting the acrylic fiber (acrylic polymer). The acrylic pulp refers to a so-called fibril-like product having a structure in which a large number of fine fibrils are branched from a fibrous trunk in an acrylic fiber.
In the present invention, by using such an acrylic fiber or acrylic pulp, the number of contacts between the reinforcing fiber, the thermoplastic resin fiber, and the acrylic fiber can be increased. Thereby, in the base material for fiber-reinforced plastic molded bodies, it is possible to prevent the reinforcing fibers and thermoplastic resin fibers from fluffing or falling off, and to obtain a base material for fiber-reinforced plastic molded bodies having excellent handling properties. Can do.

  The acrylic fiber is preferably one obtained by mixing acrylonitrile and (meth) acrylate and making it into a fiber by a blend spinning method. In such an acrylic fiber, an acrylonitrile polymer and a (meth) acrylate polymer constitute a sea-island structure. Here, the sea-island structure means that the (meth) acrylate polymer constitutes a fine layer separation structure in the acrylonitrile polymer. In the present specification, “(meth) acrylate” means that both “acrylate” and “methacrylate” are included. "

  As the (meth) acrylate unit contained in the acrylic fiber, a monomer unit derived from alkyl (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, etc. Is mentioned. Especially, as a (meth) acrylate unit, it is preferable to use the unit derived from an alkyl (meth) acrylate, and it is more preferable to use the unit derived from a methyl (meth) acrylate or an ethyl (meth) acrylate.

  Since the acrylic fiber used in the present invention has the above-described structure, it is subdivided at the interface between the acrylonitrile unit and the (meth) acrylate unit when forming a fiber-reinforced plastic molded body, and has a thin and fine fibril shape. Fiber is obtained. In the present specification, such fibrillar acrylic fibers are referred to as acrylic pulp. In acrylic pulp, specifically, a thin fibrillar fiber of about 0.1 to 1 μm is obtained. Such a structure is considered to contribute to the improvement of flame retardancy because acrylic pulp is uniformly distributed in the sheet in addition to increasing the strength of the substrate for fiber-reinforced plastic molded body.

  The freeness (CSF) of the acrylic pulp used in the present invention is preferably in the range of 20 to 600 ml. If it is this range, sufficient intensity | strength of the base material for fiber reinforced plastic moldings will be obtained. In applications where the appearance is particularly important, it is preferable to beat the beat with a beater, a double disc refiner, a single disc refiner or the like so that the Canadian standard freeness (CSF) is 300 ml or less.

  The acrylic fiber can be mixed with the reinforcing fiber and the thermoplastic resin in a wet papermaking method or a dry papermaking method. By making paper by such a method, the acrylic fiber can be uniformly mixed in the substrate for a fiber-reinforced plastic molded body. In particular, when acrylic pulp is used, reinforcing fibers and resin fibers are entangled with the fibrillar pulp, so that the binder component described later can be reduced. Since the binder component used in the present invention is inferior in flame retardancy as compared to the matrix resin, by reducing the binder component contained in the substrate for fiber reinforced plastic molded body, a fiber reinforced plastic molded body having more excellent flame retardancy can be obtained. Can be obtained. In addition, when the acrylic pulp is beaten highly, the acrylic pulp and the reinforcing fiber or the resin fiber are sufficiently entangled, so that the binder component is not necessary. In such a case, the step of mixing the binder component before paper making and the step of impregnating the substrate for fiber-reinforced plastic molded body can be omitted.

Examples of the acrylic polymer used for the base material for the fiber reinforced plastic molded body of the present invention include emulsions of copolymers such as methyl methacrylate, ethyl methacrylate, ethyl acrylate and methyl acrylate, and those obtained by dispersing an acrylic polymer in water. Can be used.
Such an acrylic polymer can be applied to the substrate for a fiber-reinforced plastic molded body by spraying or dipping. The acrylic polymer is fixed as a binder component to the surface region of the substrate for fiber-reinforced plastic molding.

  The acrylic polymer used in the emulsion or dispersion may be a styrene copolymer or an acrylonitrile copolymer as required.

  The acrylic polymer may be any one polymer selected from methyl methacrylate, ethyl methacrylate, ethyl acrylate, and methyl acrylate. The acrylic polymer may be a copolymer of two or more monomers selected from methyl methacrylate, ethyl methacrylate, ethyl acrylate and methyl acrylate. When the acrylic polymer is a copolymer as described above, the amount of monomer used in the polymerization is 30 to 100% by mass of methyl methacrylate, 0 to 30% by mass of the total of ethyl methacrylate and ethyl ethacrylate, methyl It is preferable that acrylate is 0-20 mass%.

  The content of the acrylic polymer is preferably 0.5 to 20% by mass, more preferably 1 to 18% by mass, based on the total mass of the base material for fiber-reinforced plastic molded body, and 2 to 15 More preferably, it is mass%. By setting the content of the acrylic polymer within the above range, it is possible to mold a fiber-reinforced plastic molded body with further improved flame retardancy.

(Reinforced fiber)
The reinforcing fiber is preferably at least one selected from glass fiber, carbon fiber and aramid fiber. These reinforcing fibers may use only 1 type and may use multiple types. Moreover, you may contain the organic fiber excellent in heat resistance, such as a PBO (polyparaphenylene benzoxazole) fiber.

For example, when inorganic fiber such as carbon fiber or glass fiber is used as the reinforcing fiber, the fiber reinforced plastic molded body is heated and pressurized at the melting temperature of the thermoplastic resin contained in the substrate for the fiber reinforced plastic molded body. Can be formed.
In addition, when high heat-resistant and high-strength organic fibers such as aramid fibers are used as reinforcing fibers, a base material for fiber-reinforced plastic molded bodies suitable for precision polishing equipment that requires high smoothness is required. Can be obtained. A fiber reinforced plastic molded body formed from a fiber reinforced plastic molded body substrate containing organic fibers such as aramid as a reinforced fiber is generally a fiber reinforced plastic molded body substrate using inorganic fibers as the reinforced fiber. It has better wear resistance than the formed body.

  The mass average fiber length of the reinforcing fibers is preferably 6 to 150 mm, more preferably 6 to 100 mm, and still more preferably 8 to 60 mm. By setting the mass average fiber length of the reinforced fibers within the above range, it is possible to suppress the detachment of the reinforced fibers from the substrate for the fiber reinforced plastic molded body, and a fiber reinforced plastic molded body having excellent strength. It becomes possible to form. Moreover, the dispersibility of a reinforced fiber can be made favorable by making the mass mean fiber length of a reinforced fiber into the said range. Thereby, the fiber reinforced plastic molding after heat-press molding has good strength and appearance. In the present specification, the mass average fiber length is an average value of the fiber lengths measured for 100 fibers.

  The average fiber diameter of the reinforcing fibers is not particularly limited, but generally, fibers having a fiber diameter of about 5 to 25 μm are preferably used. In addition, in this specification, an average fiber diameter is an average value of the fiber diameter which measured the fiber diameter of 100 fibers.

(Carbon fiber)
Carbon fibers are preferably used as the reinforcing fibers. As the carbon fibers contained in the reinforcing fibers, polyacrylonitrile (PAN) -based, petroleum / coal pitch-based, rayon-based, lignin-based carbon fibers can be used. These carbon fibers may be used alone or in combination of two or more. Of these carbon fibers, polyacrylonitrile (PAN) -based carbon fibers are preferably used from the viewpoint of productivity and mechanical properties on an industrial scale.

  The mass average fiber length of the carbon fibers is preferably 6 to 100 mm, more preferably 6 to 50 mm, and still more preferably 8 to 50 mm. By setting the mass average fiber length of the carbon fiber within the above range, it is possible to prevent the carbon fiber from dropping off from the substrate for the fiber reinforced plastic molded body, and to provide a fiber reinforced plastic molded body having excellent strength. It becomes possible to mold. Moreover, the dispersibility of a reinforced fiber can be made favorable by making the mass mean fiber length of carbon fiber into the said range. Thereby, the fiber reinforced plastic molding after heat-press molding has good strength and appearance.

  The single fiber strength of the carbon fiber is preferably 4500 MPa or more, and more preferably 4700 MPa or more. Single fiber strength refers to the tensile strength of a monofilament. When such a carbon fiber is used, the bending strength is greatly improved. The single fiber strength can be measured according to JIS R7601 “Test method for carbon fiber”.

  The average fiber diameter of the carbon fibers is not particularly limited, but a preferable range is 5 to 20 μm. By setting the average fiber diameter of the carbon fibers within the above range, the strength of the fiber-reinforced plastic molded body can be increased.

  The content of the carbon fiber is preferably 30 to 70% by mass, more preferably 35 to 70% by mass, and more preferably 40 to 70% by mass with respect to the total mass of the base material for fiber-reinforced plastic molded body. More preferably. By setting the carbon fiber content within the above range, it is possible to mold a fiber-reinforced plastic molded article having more excellent flame retardancy.

(Thermoplastic resin)
The base material for fiber-reinforced plastic molded articles of the present invention contains a thermoplastic resin. The thermoplastic resin is preferably a thermoplastic resin fiber, and a binding point is formed at the intersection of the matrix or fiber component during the heat and pressure treatment. By using such a thermoplastic resin fiber, it is possible to shorten the heat and pressure molding time when processing the substrate for a fiber reinforced plastic molded body, and to increase the productivity of the fiber reinforced plastic molded body. .

  The thermoplastic resin includes a first resin having a limiting oxygen index of 30 or more and a second resin having a limiting oxygen index of 27 or less. In the present invention, the adhesiveness with other members can be enhanced by using such resins having different limiting oxygen indexes. Moreover, the intensity | strength of the base material for fiber reinforced plastic moldings before shaping | molding can fully be raised.

  Examples of the first resin having a limiting oxygen index of 30 or more include resins formed from polyetherimide (PEI), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyphenylene sulfide (PPS), and the like. can do. The limiting oxygen index (LOI) of polyetherimide is 47, the limiting oxygen index (LOI) of polyetheretherketone is 43, the limiting oxygen index (LOI) of polyetherketoneketone is 47, and polyphenylene. The limit oxygen index (LOI) of sulfide is 33. Among these, the first resin is preferably at least one selected from polyetherimide and polyphenylene sulfide.

  As the second resin having a limiting oxygen index of 27 or less, a resin formed from polycarbonate (PC), acrylic, polyethylene (PE), polypropylene (PP), polyester, polyamideimide (PAI), polyamide (PA), etc. It can be illustrated. These resins can be selected according to the application. The limiting oxygen index (LOI) of polycarbonate is 26, the limiting oxygen index (LOI) of acrylic is 19, the limiting oxygen index (LOI) of polyethylene is 17, and the limiting oxygen index (LOI) of polypropylene is The limiting oxygen index (LOI) of the polyester is 18, and the limiting oxygen index (LOI) of the polyamide is 24. Among these, from the viewpoint of impact resistance, the second resin is preferably at least one selected from polycarbonate, polyester, and polyamide, and more preferably polycarbonate. As the polyamide, nylon 6 can be preferably exemplified from the viewpoint of strength. In the wet papermaking method, core-sheath binder fibers of polyethylene terephthalate and modified polyethylene terephthalate are also preferably used.

  In the present invention, the “limit oxygen index” represents an oxygen concentration necessary for continuing combustion, and is a numerical value measured by a method described in JIS K7201. The critical oxygen index of 20 or less is a numerical value indicating that combustion is performed in normal air.

  The glass transition temperatures of the first resin and the second resin are preferably 140 ° C. or higher. The first resin and the second resin are required to be sufficiently fluid under temperature conditions of 300 ° C. to 400 ° C. when forming a fiber-reinforced plastic molded body. In addition, even if it is the 1st resin (super engineering plastic resin) whose glass transition temperature is less than 140 degreeC like PPS resin, if the super engineering plastic whose resin deflection temperature becomes 190 degreeC or more is fiberized It can be used.

  The first resin and the second resin are preferably fibrous. The mass average fiber lengths of the first resin fiber and the second resin fiber are each preferably 2 to 100 mm, more preferably 2 to 50 mm, still more preferably 5 to 50 mm. More preferably, it is -40 mm, and it is especially preferable that it is 10-25 mm. By setting the mass average fiber length of the thermoplastic resin fiber within the above range, it is possible to prevent the thermoplastic resin fiber from dropping off from the substrate for the fiber reinforced plastic molded article, and the fiber reinforced plastic excellent in handling property. A substrate for a molded body can be obtained. Moreover, since the dispersibility of a thermoplastic resin fiber can be made favorable by making mass average fiber length into the said range, it becomes possible to form the fiber reinforced plastic molding excellent in intensity | strength. Thereby, the fiber reinforced plastic molding after heat-press molding has good strength and appearance.

  In this invention, content of 2nd resin can be 3-20 mass% with respect to the total mass of the base material for fiber reinforced plastic moldings, and can also be 5-18 mass%. By making content of 2nd resin in the said range, flame retardance can be improved, improving adhesiveness with another member.

  In the base material for a fiber-reinforced plastic molded body of the present invention, the mass ratio of the first resin and the second resin can be 50:50 to 99: 1, or can be 50:50 to 90:10. it can. By setting the mass ratio of the first resin and the second resin within the above range, the flame retardancy can be improved while improving the adhesion to other members.

  In the base material for a fiber-reinforced plastic molded body of the present invention, it is preferable that the thermoplastic resin is in a fiber form, whereby voids can be present in the base material. Thus, since the thermoplastic resin maintains the fiber form before heat-press molding, the base material itself is flexible and draped before forming the fiber-reinforced plastic molded body. For this reason, it is possible to store and transport the substrate for fiber-reinforced plastic molded body in the form of winding, and it is characterized by excellent handling properties.

(Blend ratio of reinforcing fiber and thermoplastic resin)
In the base material for a fiber-reinforced plastic molded body of the present invention, the mass ratio of the reinforcing fiber and the thermoplastic resin is preferably 10:90 to 80:20, more preferably 20:80 to 70:30, More preferably, it is 30: 70-70: 30. By setting the mass ratio of the reinforcing fiber and the thermoplastic resin within the above range, a lightweight and high-strength fiber-reinforced plastic molded body can be obtained.

(Binder component)
It is preferable that the base material for fiber-reinforced plastic molded bodies of the present invention further includes a binder component. The binder component is preferably contained in an amount of 0.1 to 10% by mass, more preferably 0.3 to 9% by mass, based on the total mass of the substrate for fiber-reinforced plastic molded body. More preferably, it is 0.4-8 mass%, and it is especially preferable that it is 0.5-7 mass%. By making content of a binder component into the said range, the intensity | strength in a manufacturing process can be raised and handling property can be improved. Note that as the amount of the binder component increases, both the surface strength and the interlayer strength increase, but conversely, the problem of odor during heat forming tends to occur. However, in the above-mentioned range, the problem of odor hardly occurs, and a substrate for a fiber-reinforced plastic molded body that does not cause delamination even after repeated cutting steps can be obtained. The acrylic polymer described above may function as a binder component. However, in the present invention, the content of the binder component refers to the content of the binder component excluding the acrylic polymer described above.

  As binder components, polyester resins such as polyethylene terephthalate and modified polyethylene terephthalate, which are generally used for the production of nonwoven fabrics, styrene- (meth) acrylate copolymer resins, urethane resins, PVA resins, various starches, cellulose derivatives , Polyacrylic acid soda, polyacrylamide, polyvinylpyrrolidone, acrylamide-acrylic acid ester-methacrylic acid ester copolymer, styrene-maleic anhydride copolymer alkali salt, isobutylene-maleic anhydride copolymer alkali salt, polyvinyl acetate Resins, styrene-butadiene copolymers, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate copolymers, styrene-butadiene- (meth) acrylate copolymers, and the like can be used.

Preferred binder components in the present invention include polyester resins and modified polyester resins. As the polyester resin, polyethylene terephthalate (PET) is particularly preferable. The modified polyester resin is not particularly limited as long as the melting point is lowered by modifying the polyester resin, but modified polyethylene terephthalate is preferable. As the modified polyethylene terephthalate, copolymerized polyethylene terephthalate (coPET) is preferable, and examples thereof include urethane-modified copolymerized polyethylene terephthalate. The polyester resin is preferably used because it is compatible with the thermoplastic resin at the time of heat-melting, and thus it is difficult to impair the function of heat and resin even after cooling.
The copolymerized polyethylene terephthalate preferably has a melting point of 140 ° C. or lower, more preferably 120 ° C. or lower. Moreover, you may use the modified polyester resin as described in Japanese Patent Publication No. 1-30926. As a specific example of the modified polyester resin, “Melty 4000 (trade name)” (a fiber in which all fibers are copolymerized polyethylene terephthalate) manufactured by Unitika Co., Ltd. is particularly preferable. As the core-sheath-structured binder fiber, “Melty 4080 (trade name)” manufactured by Unitika Ltd., “N-720 (trade name)” manufactured by Kuraray Co., Ltd. and the like can be suitably used.

  In the present invention, the resin used as the binder component may have a critical oxygen index of 27 or less. In general, a resin used as a binder component has a low critical oxygen index. However, the binder can be unevenly distributed in the surface layer region by applying an emulsion liquid or an aqueous solution (PVA or the like) of the binder by spraying or dipping and rapidly drying one surface using a Yankee dryer or the like. By setting it as such a structure, a flame retardance can be improved more effectively.

  The substrate for fiber-reinforced plastic molded body of the present invention preferably further contains a binder component, but since it contains an acrylic polymer, the handling property can be improved without adding the binder component. Moreover, since the base material for fiber-reinforced plastic molded articles of the present invention contains an acrylic polymer, the amount of other binder components added can be suppressed more than usual.

(Fiber shape)
In the present invention, the thermoplastic resin fibers and the reinforcing fibers are preferably chopped strands cut to a certain length. The binder fiber is also preferably chopped strand. By setting it as such a form, various fibers can be mixed uniformly in the base material for fiber reinforced plastic moldings. Moreover, the cross-sectional shape of the fiber is not limited to a circular shape, and an elliptical shape or a modified cross-sectional shape can also be used.

(Manufacturing method of base material for fiber reinforced plastic molding)
The process for producing a substrate for fiber-reinforced plastic molded body of the present invention includes a step of mixing a reinforcing fiber and a thermoplastic resin fiber and forming a substrate for fiber-reinforced plastic molded body by a wet papermaking method or a dry papermaking method. . The wet papermaking method is a method in which chopped strands of thermoplastic resin fibers and reinforcing fibers are dispersed in a solvent, and then the solvent is removed to form a web. The dry papermaking method is a method in which reinforcing fibers and thermoplastic resin fibers are mixed in a gas and then captured on a net to obtain a mat. Such a method is sometimes called airlaid.

  In the process of forming the substrate for fiber reinforced plastic molded body, in addition to the reinforced fiber and the thermoplastic resin fiber, an acrylic polymer is mixed, and the substrate for fiber reinforced plastic molded body is formed by a wet papermaking method or a dry papermaking method. It may be a step of forming. In this case, the acrylic polymer is preferably an acrylic fiber. In the above step, a binder fiber may be further mixed to make paper.

  In addition, when an acrylic polymer is mixed with an emulsion liquid or an aqueous solution and applied to a fiber reinforced plastic molded body substrate by spraying or dipping, the acrylic polymer is further added after the step of forming the fiber reinforced plastic molded body substrate. You may include the process of mixing with the emulsion liquid or aqueous solution containing a polymer, and spraying or dipping. In this case, the binder fiber may be mixed in the step of forming the substrate for fiber-reinforced plastic molded body, and the binder component may be mixed in the emulsion liquid or the aqueous solution.

  Preferably, the step of producing the substrate for fiber-reinforced plastic molded body includes a step of internally adding, applying or impregnating a nonwoven fabric with a solution containing a binder component or an emulsion containing a binder component, followed by heating and drying. That is, the step of forming the substrate for fiber-reinforced plastic molded body includes the step of manufacturing the substrate for fiber-reinforced plastic molded body by a wet papermaking method, and internally adding, applying or impregnating a solution containing a binder component to the nonwoven fabric. It is preferable to include a process. Further, after the internal addition, coating or impregnation, a step of drying by heating is included. By providing such a process, it is possible to suppress the scattering, fluffing and dropping off of the surface fibers of the substrate for fiber reinforced plastic molding, and to obtain a substrate for fiber reinforced plastic molding having excellent handling properties. it can.

  In addition, after the solution containing the binder component or the emulsion containing the binder component is internally added, applied or impregnated to the fiber reinforced plastic molded body substrate, the fiber reinforced plastic molded body substrate may be rapidly heated. preferable. By providing such a heating step, the solution containing the binder component or the emulsion containing the binder component can be transferred to the surface layer region of the substrate for fiber-reinforced plastic molded body. In addition, the binder component can be localized in the form of a water scraping film.

  When making a substrate for a fiber reinforced plastic molded body by a wet papermaking method, it is preferable to make a paper using a circular net paper machine, a long net paper machine, or an inclined type paper machine.

(Fiber reinforced plastic molding)
The present invention also relates to a fiber reinforced plastic molded article containing a reinforced fiber, a thermoplastic resin, and an acrylic polymer. The thermoplastic resin fiber contained in the fiber-reinforced plastic molded article of the present invention includes a first resin having a limiting oxygen index of 30 or more and a second resin having a limiting oxygen index of 27 or less. The acrylic polymer is preferably a polymer containing an acrylonitrile unit, and more preferably a polymer containing an acrylonitrile unit and a (meth) acrylate unit.

  Moreover, the fiber-reinforced plastic molded body of the present invention has excellent flame retardancy. Specifically, in the UL94 test (20 mm vertical combustion test), V-1 evaluation or V-0 evaluation is preferable, and V-0 evaluation is more preferable. In addition, the upper end of the fiber reinforced plastic molded body (width 13 mm, length 125 mm) is vertically attached to the clamp, and 6-inch flame is contacted twice at the center of the lower end (side in the width direction). When the combustion time is measured, the combustion time is preferably within 15 seconds, more preferably within 12 seconds, further preferably within 10 seconds, and particularly preferably within 8 seconds. The total burning time of the five fiber reinforced plastic moldings is preferably 55 seconds or less, more preferably 50 seconds or less, further preferably 45 seconds or less, and 40 seconds or less. It is particularly preferred.

  The thickness of the fiber-reinforced plastic molded body is preferably 1 mm or less, more preferably 0.7 mm or less, and further preferably 0.5 mm or less. The fiber-reinforced plastic molded body of the present invention is thinned as described above, and can exhibit excellent flame retardancy.

  The fiber reinforced plastic molded article of the present invention may have a single layer structure or a multilayer structure. For example, the fiber-reinforced plastic molded body preferably has a multilayer structure including a first layer and a second layer. In such a case, the first layer includes reinforcing fibers and a first resin having a limiting oxygen index of 30 or more, and the second layer includes reinforcing fibers and a first resin having a limiting oxygen index of 30 or more. And a second resin having a critical oxygen index of 27 or less. When the first layer contains the second resin, the content of the second resin contained in the second layer is preferably higher than the content of the second resin contained in the first layer. . By setting it as such a structure, the flame retardance of a fiber reinforced plastic molding can be improved more effectively. Moreover, it becomes possible to improve adhesiveness with another member.

  In this invention, content of 2nd resin can be 3-20 mass% with respect to the total mass of a fiber reinforced plastic molding, and can also be 5-18 mass%. By making content of 2nd resin in the said range, flame retardance can be improved, improving adhesiveness with another member.

  In the fiber-reinforced plastic molded article of the present invention, the mass ratio of the first resin and the second resin can be 50:50 to 99: 1, and can also be 50:50 to 90:10. By setting the mass ratio of the first resin and the second resin within the above range, the flame retardancy can be improved while improving the adhesion to other members.

(Molding method of fiber reinforced plastic molding)
The fiber-reinforced plastic molded article of the present invention is molded by subjecting the above-mentioned fiber-reinforced plastic molded article substrate to heat-press molding. The base material for a fiber reinforced plastic molded body can be processed into an arbitrary shape according to the target shape and molding method. The fiber-reinforced plastic molded body is a gold-reinforced plastic molded body that is either a single sheet or a laminate that has a desired thickness and is heated and pressed by hot pressing, or preheated with an infrared heater or the like in advance. It is molded by heating and pressing with a mold. When the fiber reinforced plastic molded body has a multilayer structure, other types of fiber reinforced plastic molded body substrates can be laminated and heated and pressed by hot pressing. The fiber-reinforced plastic molded body of the present invention is processed using a general method for heating and pressing a substrate for fiber-reinforced plastic molded bodies.

  Among the various press forming methods, the press molding method includes an autoclave method that is often used when forming a molded body member such as a large aircraft, and a die press method in which the process is relatively simple. Preferably mentioned. The autoclave method is preferred from the viewpoint of obtaining a high-quality molded product with few voids. On the other hand, from the viewpoint of energy consumption in equipment and molding process, simplification of jigs and auxiliary materials to be used, molding pressure, and flexibility of temperature, the metal mold is made using a metal mold. It is preferable to use a mold press method, and these can be selected according to the application.

  For the die pressing method, a heat and cool method or a stamping molding method can be employed. In the heat and cool method, a substrate for a fiber reinforced plastic molded body is placed in a mold in advance, pressurized and heated together with the mold clamping, and then the mold is cooled while the mold is cooled. This is a method for obtaining a molded body by cooling. In the stamping molding method, the base material is previously heated by a heating device such as a far-infrared heater, a heating plate, a high-temperature oven, and dielectric heating, and the thermoplastic resin is melted and softened, and then placed inside the molded body mold. Next, the mold is closed, the mold is clamped, and then the pressure is cooled. Moreover, when the temperature at the time of shaping | molding is comparatively low, such as when obtaining a low density molded object, a hot press method can also be employ | adopted.

  Molds for molding are roughly classified into two types, one is a sealed mold used for casting or injection molding, and the other is an open mold used for press molding or forging. When the base material for a fiber-reinforced plastic molded body of the present invention is used, any mold can be used depending on the application. An open mold is preferable from the viewpoint of eliminating decomposition gas and mixed air from the mold during molding, but in order to suppress excessive resin flow, the number of open parts should be reduced as much as possible during the molding process. It is also preferable to adopt a shape that suppresses outflow from the mold.

  Furthermore, the metal mold | die which has at least 1 type selected from a punching mechanism and a tapping mechanism can be used for a metal mold | die. It is also possible to punch the formed body continuously after hot pressing by means such as using a two-stage press mechanism. In addition, depending on the purpose of use, the molded body can be provided with a pattern for the purpose of reinforcing strength such as ribs and bosses, forming projections and screw holes for processing, and imparting design properties.

  When the fiber reinforced plastic molded body has a multilayer structure, other types of fiber reinforced plastic molded body substrates can be laminated and heat-press molded by hot pressing. It is also possible to bond more complicated shaped members by outsert molding or insert molding at the same time as or after molding the fiber-reinforced plastic molded body.

  When molding a fiber reinforced plastic molded body from a fiber reinforced plastic molded body substrate, specifically, it is preferable to heat and pressure mold the fiber reinforced plastic molded body substrate at a temperature of 150 to 600 ° C. . The heating temperature is preferably a temperature range in which the thermoplastic resin fibers flow and the reinforcing fibers do not melt.

  As a pressure at the time of shape | molding a fiber reinforced plastic molding, 5-20 Mpa is preferable. Further, the rate of temperature rise until reaching the desired holding temperature is preferably 3 to 20 ° C./min. The holding time at the desired hot press temperature is 1 to 30 minutes, and then the temperature at which the molded body is taken out (200 ° C. It is preferable to set it as a cooling rate of 3-20 degree-C / min, maintaining a pressure until below. Furthermore, although the production efficiency is slightly lowered, it is also preferable from the viewpoint of improving the strength to cool slowly by air cooling from the holding temperature of the hot press to the glass transition temperature of the thermoplastic resin at 0.1 to 3 ° C./min. It is also possible to perform hot press molding using rapid heating and rapid cooling (heat and cool) molding, in which case the temperature rise and cooling rate are 30 to 500 ° C./min, respectively. Furthermore, in the case of using an infrared heater, the temperature is 150 to 600 ° C., preferably 200 to 500 ° C., for 1 to 30 minutes, and then molded at a pressure of 30 to 150 MPa.

(Surface layer containing fiber reinforced plastic molding)
The fiber-reinforced plastic molded body of the present invention may further have a surface layer. As described above, when the fiber-reinforced plastic molded body has the first layer and the second layer, it is preferable to provide a surface layer on the surface of the first layer.

  The surface layer should just contain 50 mass% or more of at least 1 sort (s) selected from polyolefin, polyetherimide, polyphenylene sulfide, nylon, polystyrene, and polyphenylene ether. The surface layer preferably contains at least one selected from polyolefin, polyetherimide, polyphenylene sulfide, nylon, polystyrene, and polyphenylene ether in an amount of 80% by mass or more, more preferably 90% by mass or more, and 95% by mass. % Or more is more preferable, and 99% by mass or more is particularly preferable. Among these, the surface layer is particularly preferably a layer made of at least one selected from polyolefin, polyetherimide, polyphenylene sulfide, nylon, polystyrene, and polyphenylene ether. In addition, a surface layer may be comprised only from said 1 type, and may be comprised from the mixture of said resin. Moreover, resins other than the above resins may be used in combination.

  A fiber-reinforced plastic molded body having a surface layer has high coating suitability, and it is possible to apply a uniform coating on the surface layer. Thereby, the fiber reinforced plastic molding with high designability can be obtained.

(Applications of fiber-reinforced plastic moldings)
Examples of the use of the fiber-reinforced plastic molded body of the present invention include: “OA devices, mobile phones, smartphones, personal digital assistants, tablet PCs, digital video cameras and other portable electronic devices, air conditioners and other housings for home appliances, and the like. Reinforcing materials such as ribs to be attached to the housing, civil engineering such as "posts, panels, reinforcing materials", building material parts, "various frames, various wheel bearings, various beams, doors, trunk lids, side panels, upper back panels , Front body, underbody, various pillars, various frames, various beams, various supports, etc. or body parts and reinforcements thereof, “interior parts such as instrument panels and seat frames”, or “gasoline tanks, Fuel systems such as various pipes and various valves, exhaust systems, or intake system parts ”,“ Automotive parts such as engine cooling water joints, thermostat bases for air conditioners, headlamp supports, pedal housings, aircraft parts such as winglets and spoilers, seat parts for rail vehicles, outer panels , Reinforcement materials to be affixed to the outer panel, ceiling panels, jet outlets for air conditioners, etc., “Reinforcement for molded products made of resin (thermosetting resin, thermoplastic resin), resin and reinforcement Reinforcing materials for molded products made of fibers, and materials such as plant-derived sheets (craft paper, cardboard, oil-resistant paper, insulating paper, conductive paper, release paper, impregnated paper, glassine paper, cellulose nanofiber sheet, etc.) Etc. are preferably used. Furthermore, since the fiber-reinforced plastic molded article of the present invention is excellent in flame retardancy even when thin, it can be suitably used as a substrate for electrical insulation by using glass fibers having high electrical insulation as the reinforcing fibers.
As described above, the fiber-reinforced plastic molded body of the present invention has high strength and has excellent flame retardancy, so it has high safety. Therefore, the housing for electric and electronic devices, structural parts for automobiles, and aircraft It is preferably used for various parts, civil engineering, building material panels, and other various applications.

(Outsert molded product)
An outsert molded member may be attached and fixed to the surface of the fiber-reinforced plastic molded body of the present invention to form an outsert molded body. The outsert molded member is preferably molded by the outsert injection molding method on the surface of the fiber-reinforced plastic molded body. In addition, as mentioned above, when a fiber reinforced plastic molding has a 1st layer and a 2nd layer, it is preferable to provide an outsert molding member on the surface of a 2nd layer.

  The outsert molded member preferably contains injection reinforcing fibers and injection thermoplastic resin. Here, it is preferable that at least a part of the thermoplastic resin and the thermoplastic resin for injection contained in the second layer of the fiber reinforced plastic molded body is the same type of resin. Furthermore, it is more preferable that the second resin contained in the second layer has a critical oxygen index of 27 or less and at least a part of the injection thermoplastic resin is the same type. For example, when the second resin contained in the second layer is polycarbonate, the injection thermoplastic resin preferably contains polycarbonate. By including such a resin, the second resin contained in the second layer and the thermoplastic resin for injection are compatible with each other, so that the bondability between the outsert molded member and the fiber-reinforced plastic molded body is improved. be able to.

  Examples of reinforcing fibers for injection include reinforcing fibers that can be used for fiber-reinforced plastic molded articles. Examples of the thermoplastic resin for injection include thermoplastic resins such as polycarbonate resin, polyamide, and polypropylene, and the second resin can be exemplified as a preferred resin.

  The outsert molded member can have a complicated shape and a fine structure. For this reason, the outsert molded body includes a personal computer, a display, an OA device, a mobile phone, a portable information terminal, a facsimile, a compact disc, a portable MD, a portable radio cassette, a PDA (a portable information terminal such as an electronic notebook), a video camera, It is preferably used for electrical and electronic equipment parts such as a casing, tray, chassis, interior member, or case of a digital video camera, optical equipment, audio, air conditioner, lighting equipment, entertainment goods, toy goods, and other household appliances.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

<Example 1>
(Preparation of nonwoven fabric for first layer)
Carbon fiber having a fiber length of 12 mm (manufactured by Taiwan Plastic Co., Ltd., CS815) was introduced into water so that the slurry concentration became 0.5%, and Emanon (registered trademark) 3199V (manufactured by Kao Corporation) was used as a dispersant. It added so that it might become 1 mass part with respect to a mass part. In addition, Emanon 3199V was dissolved in water and added in advance so as to obtain an aqueous solution having a concentration of 0.5%. Thereafter, initial dispersion was carried out by stirring for 30 seconds using a waste paper disaggregating pulper, and then diluted with water to a slurry concentration of 0.15% (carbon fiber slurry).

  In a separate container, a 0.1% aqueous solution of “Sumifloc”, a powdered anionic polymer polyacrylamide thickener, was prepared. This was added to the carbon fiber slurry so that the solid content of the thickener was 60 ppm with respect to the entire liquid. Then, it stirred and disperse | distributed until carbon fiber became monofilament almost completely.

  Subsequently, a polyetherimide fiber having a thickness of 2.2 dtex and a fiber length of 15 mm was weighed so as to have a blending ratio shown in Table 2. This was poured into water separated into a separate container so that the slurry concentration was 10% to obtain a polyetherimide fiber slurry. In addition, since the polyetherimide fiber had good dispersibility, it was sufficiently dispersed without any particular treatment such as stirring.

  Furthermore, acrylonitrile pulp (manufactured by Mitsubishi Rayon Co., Ltd., C300HS) was introduced into water so as to have a slurry concentration of 2.0%, and disaggregated with a waste paper disaggregating pulper for 3 minutes to obtain acrylonitrile pulp slurry.

The polyetherimide fiber slurry and the acrylonitrile pulp slurry were charged into the carbon fiber slurry so as to have the blending ratio described in the first layer of Table 2 (first raw material slurry).
And this 1st raw material slurry was continuously supplied to the inclination wire type paper machine, and papermaking was carried out at the speed of 5.5 L / min, and the nonwoven fabric for 1st layers of width 50cm and basic weight 250g / m ² was obtained. .

(Preparation of second layer nonwoven fabric)
A 0.15% concentration carbon fiber slurry was prepared in the same manner as the first layer nonwoven fabric preparation procedure. Then, the polyetherimide fiber and the polycarbonate fiber (Daiwabo Co., Ltd., fiber diameter 30 μm, fiber length 15 mm) are lightened so as to have the mixing ratio of the second layer in Table 2, and the polyetherimide fiber slurry for the first layer A polyetherimide fiber and a polycarbonate fiber slurry were obtained in the same manner as described above. Moreover, the acrylonitrile pulp slurry was produced by the method similar to the 1st layer. Polyetherimide fiber, polycarbonate fiber slurry, and acrylonitrile pulp slurry were added to the carbon fiber slurry so as to have the mixing ratio of the second layer in Table 2 (raw material slurry for the second layer). Then, the second raw material slurry is continuously supplied to the inclined wire type paper machine, and paper making is performed at a speed of 5.5 L / min to obtain a nonwoven fabric for the second layer having a width of 50 cm and a basis weight of 100 g / m ² . It was.

  Two obtained nonwoven fabrics for the first layer were laminated, and one nonwoven fabric for the second layer was further laminated thereon to produce a substrate for a fiber reinforced plastic molded body. The substrate for fiber reinforced plastic molded body was pressed at a press pressure of 10 MPa and a heating temperature of 300 ° C. for 5 minutes, and cooled to 70 ° C. to obtain a fiber reinforced plastic molded body. In addition, the compounding ratio of the fiber of each layer of a fiber reinforced plastic molding is the same as the compounding ratio of each layer of the base material for fiber reinforced plastic moldings.

<Example 2>
A fiber-reinforced plastic molded article was obtained in the same manner as in Example 1 except that the blending ratio of the first layer nonwoven fabric and the second layer nonwoven fabric was changed so as to achieve the blending ratio shown in Table 2.

<Example 3>
A fiber-reinforced plastic molded article was obtained in the same manner as in Example 1 except that the blending ratio of the first layer nonwoven fabric and the second layer nonwoven fabric was changed so as to achieve the blending ratio shown in Table 2.

<Example 4>
PVA fiber (manufactured by Kuraray Co., Ltd., VPB-105-1) was poured into water dispensed into a container so as to be a 1% slurry, and stirred. This was added to the carbon fiber slurry so that the blending ratio shown in Table 2 was obtained. Further, a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the fiber blending ratio of the first layer nonwoven fabric and the second layer nonwoven fabric was changed as shown in Table 2.

<Example 5>
Para-aramid pulp (manufactured by Teijin Ltd., Twaron 1094) was added to a waste paper pulper so as to form a 2% slurry. This was added to the carbon fiber slurry so that the blending ratio shown in Table 2 was obtained. Further, a fiber-reinforced plastic molded body was obtained in the same manner as in Example 1 except that the fiber blending ratio of the first layer nonwoven fabric and the second layer nonwoven fabric was changed as shown in Table 2.

<Example 6>
A fiber-reinforced plastic molded article was obtained in the same manner as in Example 1 except that the blending ratio of the first layer nonwoven fabric and the blending ratio of the second layer nonwoven fabric were changed as shown in Table 2. In addition, PET (PET-modified PET core-sheath binder fiber, manufactured by Kuraray Co., Ltd., N-720) and PVA fiber (manufactured by Kuraray Co., Ltd., VPB-105-1) are weighed so as to have a blending ratio shown in Table 2. The slurry was poured into water to a slurry concentration of 1%, stirred and dispersed, and then poured into the carbon fiber slurry liquid for forming the second layer nonwoven fabric.

<Example 7>
A fiber-reinforced plastic molded article was obtained in the same manner as in Example 6 except that the blending ratio of the first layer nonwoven fabric was changed as shown in Table 2. In addition, the acrylic emulsion (Dainippon Ink Co., Ltd., GM-4) was diluted to a solid content concentration of 6% and added by spraying before the dryer.

<Examples 8 and 9>
A fiber-reinforced plastic molded article was obtained in the same manner as in Example 5 except that the blending ratio of the first layer nonwoven fabric and the blending ratio of the second layer nonwoven fabric were changed as shown in Table 2.

<Comparative Examples 1-5>
A fiber-reinforced plastic molded article was obtained in the same manner as in Example 6 except that the blending ratio of the first layer nonwoven fabric was changed as shown in Table 3.

<Comparative Example 6>
Except for changing the blending ratio of the first layer nonwoven fabric and the second layer nonwoven fabric as shown in Table 3 and changing the paper machine to a 25 cm square square handsheet as defined in JIS P8222. A fiber-reinforced plastic molded body was obtained in the same manner as in Example 1.

<Evaluation>
(Flammability test)
The flame retardancy of the fiber reinforced plastic moldings obtained in Examples and Comparative Examples was evaluated by UL94 test (20 mm vertical combustion test). Specifically, the upper end of a fiber reinforced plastic molded body (width 13 mm, length 125 mm) is vertically attached to the clamp, and 6-inch flame is contacted twice at the center of the lower end (side in the width direction), followed by fiber reinforced plastic. The burning time of the compact was measured. Immediately after the fire was extinguished, the flame was removed again for 20 seconds. The above-mentioned combustion test was conducted with five fiber reinforced plastic moldings, and the burning time of each fiber reinforced plastic molding and the total burning time of the five were recorded.

Subsequently, the flame retardancy was evaluated according to the criteria shown in Table 1 below. Specifically, the time (growing time) in which the fiber-reinforced plastic molded body was in a smoking state after flame contact was measured. Further, it was examined whether or not the fiber-reinforced plastic molded body burned up to the clamp portion. Furthermore, when the fiber-reinforced plastic molded body was burned, the presence or absence of ignition of surgical absorbent cotton placed under 12 inches was recorded.
The evaluation criteria for flame retardancy are as shown in Table 1 below. V-0 has the highest flame retardancy, and the flame retardancy decreases in the order of V-1 and V-2.
In the present invention, the one that has achieved the V-1 level and the total burning time of the five test pieces is 50 seconds or less is regarded as the acceptable level.

  Compared with the comparative example, in the example, it can be seen that the combustion time of the molded body is shortened and the flame retardancy is improved. In the examples, it can be seen that the flame retardancy is improved even when the ratio of the resin having a critical oxygen index of 27 or less is high.

Claims (14)

Including reinforcing fibers, thermoplastic resins, and acrylic polymers,
The base material for a fiber-reinforced plastic molded article, wherein the thermoplastic resin includes a first resin having a critical oxygen index of 30 or more and a second resin having a critical oxygen index of 27 or less.   The base material for a fiber-reinforced plastic molded body according to claim 1, wherein the acrylic polymer is an acrylic fiber.   The base material for a fiber-reinforced plastic molded body according to claim 1 or 2, wherein the acrylic polymer includes an acrylonitrile unit.   The base material for a fiber-reinforced plastic molded body according to any one of claims 1 to 3, wherein the acrylic polymer is an acrylic pulp containing an acrylonitrile unit and a (meth) acrylate unit.   The fiber-reinforced plastic molding according to any one of claims 1 to 4, wherein a content of the acrylic polymer is 0.5 to 20% by mass with respect to a total mass of the base material for the fiber-reinforced plastic molded body. Body substrate.   The substrate for fiber-reinforced plastic molded bodies according to any one of claims 1 to 5, wherein the reinforcing fibers are carbon fibers.   7. The fiber-reinforced plastic molded body according to claim 1, wherein the content of the reinforcing fiber is 30 to 70% by mass with respect to the total mass of the base material for the fiber-reinforced plastic molded body. Base material.   Furthermore, the base material for fiber reinforced plastic moldings of any one of Claims 1-7 containing a binder component. Including reinforcing fibers, thermoplastic resins, and acrylic polymers,
The thermoplastic resin is a fiber-reinforced plastic molded article including a first resin having a limiting oxygen index of 30 or more and a second resin having a limiting oxygen index of 27 or less.   The fiber-reinforced plastic molded article according to claim 9, wherein the acrylic polymer includes an acrylonitrile unit.   The fiber-reinforced plastic molded article according to claim 9 or 10, wherein the acrylic polymer includes an acrylonitrile unit and a (meth) acrylate unit.   The fiber-reinforced plastic molded body according to any one of claims 9 to 11, having a thickness of 1 mm or less.   The fiber-reinforced plastic molded article according to any one of claims 9 to 12, which has a thickness of 0.5 mm or less. The fiber-reinforced plastic molded body includes a first layer and a second layer,
The first layer includes the reinforcing fiber and the first resin,
The second layer includes the reinforcing fiber, the first resin, and the second resin,
When the first layer contains a second resin, the content of the second resin contained in the second layer is higher than the content of the second resin contained in the first layer. The fiber-reinforced plastic molded body according to any one of 9 to 13.