Resin composition, method for manufacturing the resin composition, and molded article

Abstract

The purpose of the present invention is to provide: a resin composition from which a molded article having excellent mechanical properties and high elasticity can be produced; and a molded article produced form the resin composition.　Provided is a resin composition comprising a fluororesin that can be melted and molded and inorganic fibers, in which the content ratio of the fluororesin relative to the total amount of the fluororesin and the inorganic fibers is 60 to 95% by mass, the inorganic fibers are inorganic fibers in which at least a portion of the surface thereof has been subjected to a sizing treatment with a sizing agent, and the mass decrease rate after the inorganic fibers are heated at 400°C for 60 minutes is 3% or less. Also provided are: a method for producing the resin composition; and a molded article produced by molding the resin composition.

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a method for producing a resin composition, and a molded article of the resin composition. [Background technology]

[0002] Fluoropolymers are used in a wide range of applications, such as corrosion-resistant piping materials for chemical plants, materials for agricultural greenhouses, release coating materials for kitchen equipment, and insulation materials for electric wires, due to their excellent heat resistance, flame retardancy, chemical resistance, weather resistance, non-stick properties, low friction, and low dielectric properties. On the other hand, fluoropolymers may be inferior to general engineering plastics in terms of strength properties such as tensile strength and flexural strength. To improve the strength and physical properties of fluororesins, fillers are sometimes added to them (for example, Patent Document 1). The resin composition described in Patent Document 1 is characterized by comprising a crystalline resin having a melting point of 290°C or higher, graphite filaments (A) with a crystallite size of 30.0 Å or less in the c-axis direction, and graphite filaments (B) with a crystallite size of more than 100.0 Å in the c-axis direction. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-203125 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, in the case of the resin composition described in Patent Document 1, the strength properties of the molded article decrease when the temperature during melt molding increases, resulting in insufficient mechanical properties depending on the application. In addition, high elasticity is sometimes required for molded articles made of fluororesin. The present invention provides a resin composition that yields molded articles with excellent mechanical properties and high elasticity, and a molded article obtained from such a resin composition. [Means for solving the problem]

[0005] The present invention encompasses the following embodiments. [1] A resin composition comprising a melt-mold fluororesin and inorganic fibers, wherein the ratio of the fluororesin to the total of the fluororesin and inorganic fibers is 60 to 95% by mass, and the inorganic fibers are inorganic fibers in which at least a portion of their surface has been sized with a sizing agent. A resin composition wherein the mass loss rate of the inorganic fibers, calculated by the following method, is 3% or less. Method for calculating the mass loss rate: The inorganic fibers are heated at 400°C for 60 minutes in the presence of air, and the mass loss rate is calculated based on the following formula (I). Mass reduction rate (%) = ((Mass of inorganic fiber before heating [g]) - (Mass of inorganic fiber after heating [g])) / (Mass of inorganic fiber before heating [g]) × 100 ... (I)

[0006] [2] The resin composition of [1], wherein the composition further comprises components other than the fluororesin and the inorganic fibers, and the content of such components is 20% by mass or less relative to the resin composition. [3] The resin composition of [1] or [2], wherein the inorganic fiber is a glass fiber or a carbon fiber. [4] A resin composition according to any of [1] to [3], wherein the average fiber length of the inorganic fibers is 100 μm to 30 mm. [5] The fluororesin is a resin composition according to any one of [1] to [4], wherein the fluororesin has a functional group selected from the group consisting of a carbonyl group-containing group, a hydroxyl group, an epoxy group, an amide group, an amino group, and an isocyanate group.

[0007] [6] A resin composition according to any of [1] to [5], wherein the fluororesin is a polymer having units based on tetrafluoroethylene, a copolymer having units based on tetrafluoroethylene and units based on ethylene, a copolymer having units based on chlorotrifluoroethylene and units based on ethylene, a copolymer having units based on tetrafluoroethylene and units based on hexafluoropropylene, a copolymer having units based on tetrafluoroethylene and units based on a compound represented by the following formula (1), or a copolymer having units based on tetrafluoroethylene, units based on a compound represented by the following formula (2), and units based on ethylene. CF2 = CFOR f1 ...(1) CH2=CX 1 (CF2) p X 2 ...(2) however, In formula (1), R f1 This is a perfluoroalkyl group having 1 to 10 carbon atoms, which may contain etheric oxygen atoms between carbon atoms. In formula (2), X 1 is a hydrogen atom or a fluorine atom, p is an integer between 2 and 10, and X 2 This is either a hydrogen atom or a fluorine atom.

[0008] [7] The resin composition of [6] wherein the fluororesin is a copolymer having units based on tetrafluoroethylene and units based on ethylene, a copolymer having units based on tetrafluoroethylene and units based on a compound represented by formula (1), or a copolymer having units based on tetrafluoroethylene, units based on a compound represented by formula (2), and units based on ethylene. [8] The resin composition of [6] or [7], wherein the fluororesin is further a polymer having units based on monomers having functional groups selected from the group consisting of carbonyl group-containing groups, hydroxyl groups, epoxy groups, amide groups, amino groups and isocyanate groups. [9] The resin composition of [8], wherein the polymer having a unit based on the monomer having the functional group is a polymer having a unit based on a monomer having a carboxy group, an acid anhydride group, a hydroxy group or an epoxy group.

[10] A production method of the resin composition according to any one of [1] to [9], which comprises melt-kneading the fluororesin and the inorganic fiber.

[11] A molded article obtained by molding the resin composition according to any one of [1] to [9]. [Advantages of the Invention]

[0009] According to the present invention, there is provided a resin composition from which a molded article having excellent mechanical properties and high elasticity can be obtained, and a molded article having excellent mechanical properties and high elasticity can be obtained from such a resin composition. [Embodiments for Carrying Out the Invention]

[0010] The meanings of the following terms in this specification are as follows. The compound represented by formula (n) is referred to as "compound (n)". Here, n is a natural number. "Monomer" means a compound having a polymerizable carbon-carbon double bond. "Unit based on a monomer" is a general term for an atomic group directly formed by polymerization of one molecule of a monomer and an atomic group obtained by chemically converting a part of the atomic group after polymerization. The unit based on a monomer is also simply referred to as "monomer unit". "Capable of melt molding" means exhibiting melt fluidity. "Exhibiting melt fluidity" means that there exists a temperature at which the melt flow rate is 0.1 to 1000 g / 10 min at a temperature 20°C or higher than the melting point of the resin under the condition of a load of 49 N. "Melting point" is the temperature corresponding to the maximum value of the melting peak measured by the differential scanning calorimetry (DSC) method. "Melt flow rate" is the melt mass flow rate (MFR) defined in JIS K 7210:1999 (ISO 1133:1997).

[0011] <Resin Composition> The resin composition of the present invention contains a fluororesin capable of melt molding and inorganic fibers. The resin composition may further contain components other than the fluororesin and the inorganic fibers (hereinafter also referred to as "other components") as long as the effects of the invention are not impaired.

[0012] (Fluororesin) The fluororesin is a fluoropolymer having a fluorine-containing monomer unit, and is not particularly limited as long as it can be melt molded. The fluorine-containing monomer is not particularly limited as long as it is a fluorine-containing compound having one polymerizable carbon-carbon double bond. Examples of the fluorine-containing monomer include, for example, fluoroolefin, a fluorine-containing compound having a ring structure, compound (1) (hereinafter also referred to as "PAVE"), compound (2) (hereinafter also referred to as "FAE"), compound (3), compound (4), and compound (5). However, the fluorine-containing monomer is not limited to these examples. Further, two or more kinds of fluorine-containing monomers may be used in combination.

[0013] CF2=CFOR f1 ···(1) CH2=CX 1 (CF2) p X 2 ···(2) CF2=CFOR f2 SO2X 3 ···(3) CF2=CFOR f3 CO2X 4 ···(4) CF2=CF(CF2) q OCF=CF2···(5) However, in formula (1), R f1 is a perfluoroalkyl group having 1 to 10 carbon atoms which may contain an etheric oxygen atom between carbon atoms, in formula (2), X 1 is a hydrogen atom or a fluorine atom, p is an integer of 2 to 10, and X 2 is a hydrogen atom or a fluorine atom, in formula (3), R f2X is a perfluoroalkylene group having 1 to 10 carbon atoms, which may contain etheric oxygen atoms between carbon atoms, 3 is a halogen atom or a hydroxyl group, In formula (4), R f3 X is a perfluoroalkylene group having 1 to 10 carbon atoms, which may contain etheric oxygen atoms between carbon atoms, 4 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In equation (5), q is either 1 or 2.

[0014] Examples of fluorine-containing compounds having a ring structure include perfluoro(2,2-dimethyl-1,3-dioxol), 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxol, and perfluoro(2-methylene-4-methyl-1,3-dioxolane).

[0015] From the viewpoint of mechanical properties, fluoroolefins, PAVE, and FAE are preferred as fluorine-containing monomers, with fluoroolefins and PAVE being preferred.

[0016] Examples of fluoroolefins include tetrafluoroethylene (hereinafter also referred to as "TFE"), vinyl fluoride, vinylidene fluoride (hereinafter also referred to as "VdF"), trifluoroethylene, chlorotrifluoroethylene (hereinafter also referred to as "CTFE"), hexafluoropropylene (hereinafter also referred to as "HFP"), and hexafluoroisobutylene. Among these, TFE and HFP are preferred in terms of moldability and mechanical properties, with TFE being more preferred.

[0017] Examples of PAVE include CF2=CFOCF2CF3, CF2=CFOCF2CF2CF3, CF2=CFOCF2CF2CF2CF3, and CF2=CFO(CF2)6F. Among these, CF2=CFOCF2CF2CF3 (hereinafter also referred to as "PPVE") is preferred in terms of mechanical properties.

[0018] For example, FAEs include CH2=CF(CF2)2F, CH2=CF(CF2)3F, CH2=CF(CF2)4F, CH2=CF(CF2)5F, CH2=CF(CF2)6F, CH2=CF(CF2)2H, CH2=CF(CF2)3H, CH2=CF(CF2)4H, CH2=CF(CF2)5H, CH2=CF(CF2)6H, and CH2=CH(CF2)2F. Examples include CH2=CH(CF2)3F, CH2=CH(CF2)4F (hereinafter also referred to as "PFBE"), CH2=CH(CF2)5F, CH2=CH(CF2)6F, CH2=CH(CF2)2H, CH2=CH(CF2)3H, CH2=CH(CF2)4H, CH2=CH(CF2)5H, CH2=CH(CF2)6H, etc.

[0019] As the FAE, compound (2-1) is preferred. CH2=CH(CF2) p1 X 2 ...(2-1) However, in formula (2-1), p1 is 2 to 6, preferably 2 to 4, and X 2 This is either a hydrogen atom or a fluorine atom.

[0020] As compound (2-1), PFEE, CH2=CH(CF2)3F, PFBE, CH2=CF(CF2)3H, and CH2=CF(CF2)4H are preferred, with PFBE and PFEE being more preferred.

[0021] Fluororesins may further contain non-fluorine monomer units in addition to fluorine-containing monomer units. The non-fluorine monomers are not particularly limited as long as they do not contain fluorine atoms. Examples include olefins such as ethylene, propylene, and 1-butene, vinyl esters such as vinyl acetate, and monomers having the functional group f described later. When a fluororesin contains non-fluorinated monomer units, two or more non-fluorinated monomers may be used in combination. From the viewpoint of excellent mechanical properties of the molded article, ethylene, propylene, and 1-butene are preferred as non-fluorinated monomers, with ethylene being particularly preferred.

[0022] The fluororesin may be a single polymer having fluorine-containing monomer units, a copolymer having two or more types of fluorine-containing monomer units, or a copolymer having one or more types of fluorine-containing monomer units and one or more types of non-fluorine monomer units. Furthermore, the resin composition of the present invention may contain two or more of these homopolymers or copolymers as fluororesins.

[0023] When the fluororesin is a copolymer having fluorine-containing monomer units and non-fluorine monomer units, the proportion of fluorine-containing monomer units is preferably 40.0 to 99.5 mol%, and more preferably 45 to 99 mol%, relative to the total of fluorine-containing monomer units and non-fluorine monomer units. If the proportion of fluorine-containing monomer units is above the lower limit of the above range, the fluororesin exhibits even greater flame retardancy, chemical resistance, and moldability. If the proportion of fluorine-containing monomer units is below the upper limit of the above range, the molded article exhibits excellent mechanical properties and is more likely to be highly elastic.

[0024] Examples of homopolymer fluororesins include polytetrafluoroethylene, polyvinylidene fluoride, polychlorotrifluoroethylene, and polyhexafluoropropylene. Examples of copolymer fluororesins include copolymers having TFE units and ethylene units, copolymers having CTFE units and ethylene units, copolymers having TFE units and HFP units, copolymers having TFE units and PAVE units, and copolymers having TFE units, FAE units and ethylene units. Among these, copolymers having TFE units and ethylene units, copolymers having TFE units, FAE units and ethylene units, and copolymers having TFE units and PAVE units are preferred in terms of mechanical properties and high elasticity. Furthermore, the fluororesin is not limited to these examples, as long as it is melt-moldable, and may also be various other homopolymers and copolymers.

[0025] When the fluororesin is a copolymer having TFE units and ethylene units, the TFE units are preferably 30 to 70 mol%, and more preferably 40 to 60 mol%, relative to the total monomer units of the copolymer. When the fluororesin is a copolymer having TFE units, FAE units, and ethylene units, it is preferable that the TFE units are 40-64 mol%, the FAE units are 1-5 mol%, and the ethylene units are 35-59 mol%, relative to the total monomer units of the copolymer, and more preferably that the TFE units are 45-59 mol%, the FAE units are 1-4 mol%, and the ethylene units are 40-54 mol%. When the fluororesin is a copolymer having TFE units and PAVE units, the TFE units are preferably 80.0 to 99.5 mol%, and more preferably 90 to 95 mol%, relative to the total monomer units of the copolymer.

[0026] The melting point of the fluororesin is preferably 100 to 325°C, and more preferably 150 to 260°C. If the melting point of the fluororesin is above the lower limit of the above range, the molded article will have excellent heat resistance. If the melting point of the fluororesin is below the upper limit of the above range, general-purpose equipment can be used when manufacturing the molded article. In addition, it is easier to obtain a molded article with excellent mechanical properties. Furthermore, if further improvement in heat resistance is required, the melting point of the fluororesin is preferably 260 to 330°C, and more preferably 270 to 325°C.

[0027] The melt flow rate of the fluororesin is preferably 0.1 to 100 g / 10 min, more preferably 0.5 to 80 g / 10 min, and even more preferably 1 to 50 g / 10 min. If the melt flow rate is above the lower limit of the above range, the fluororesin exhibits excellent moldability. If the melt flow rate is below the upper limit of the above range, a molded article with excellent mechanical properties is easily obtained.

[0028] As the fluororesin, a fluororesin having a functional group selected from the group consisting of carbonyl group-containing groups, hydroxyl groups, epoxy groups, amide groups, amino groups, and isocyanate groups (hereinafter referred to as "functional group f") is preferred (hereinafter referred to as "fluororesin A"). Fluororesin A may have two or more functional groups f. The resin composition of the present invention may contain fluororesin A and a fluororesin that does not have functional group f. Fluororesin A has adhesive functional groups f, resulting in excellent adhesion to inorganic fibers. As a result, it becomes easier to obtain molded articles with even better mechanical properties. Furthermore, it becomes easier to obtain molded articles with excellent impact resistance. From the viewpoint of adhesion to inorganic fibers, it is preferable that the functional group f is present in at least one of the terminal groups and pendant groups of the main chain of fluororesin A.

[0029] From the viewpoint of adhesion to inorganic fibers, it is preferable that fluororesin A has at least a carbonyl group-containing group as a functional group f. Examples of carbonyl group-containing groups include groups having carbonyl groups between carbon atoms of a hydrocarbon group, carbonate groups, carboxyl groups, haloformyl groups, alkoxycarbonyl groups, and acid anhydride groups.

[0030] Examples of hydrocarbon groups having carbonyl groups between carbon atoms include alkylene groups having 2 to 8 carbon atoms. Here, the number of carbon atoms in the alkylene group is the number of carbon atoms in the state excluding the carbon atoms that make up the carbonyl group. The alkylene group may be linear or branched. A haloformyl group is represented as -C(=O)-X (where X is a halogen atom). Examples of halogen atoms in a haloformyl group include fluorine atoms and chlorine atoms, with fluorine atoms being preferred. In other words, a fluoroformyl group (also called a carbonyl fluoride group) is preferred as the haloformyl group. The alkoxy group in the alkoxycarbonyl group may be linear or branched. Preferably, the alkoxy group in the alkoxycarbonyl group has 1 to 8 carbon atoms, with methoxy and ethoxy groups being particularly preferred.

[0031] The content of functional group f in fluororesin A is equal to the carbon number of the main chain of fluororesin A, which is 1 × 10 6 The amount of functional group f per unit is preferably 10 to 60,000, more preferably 100 to 50,000, even more preferably 100 to 10,000, and particularly preferably 300 to 5,000. If the content of functional group f is above the lower limit of the above range, the adhesion to inorganic fibers is remarkably excellent. If the content of functional group f is below the upper limit of the above range, the adhesion to inorganic fibers is excellent even when the temperature during melt molding is low.

[0032] The content of functional group f can be measured by methods such as nuclear magnetic resonance (NMR) analysis and infrared absorption spectroscopy. For example, as described in Japanese Patent Publication No. 2007-314720, the proportion (mol%) of units containing functional group f among all units constituting fluororesin A can be determined using methods such as infrared absorption spectroscopy, and the content of functional group f can be calculated from the proportion (mol%) of units.

[0033] Using fluororesin A, which has a relatively low melting point, allows for a lower temperature during melt molding, resulting in excellent adhesion to inorganic fibers. Therefore, from the viewpoint of adhesion to inorganic fibers, the melting point of fluororesin A is preferably 120 to 220°C, and more preferably 120 to 200°C. Using fluororesin A, which has a relatively high melting point, makes it easier to obtain molded articles with high heat resistance. Therefore, from the viewpoint of heat resistance, the melting point of fluororesin A is preferably 260 to 330°C, and more preferably 280 to 325°C. The melting point of fluororesin A can be adjusted by the type and proportion of units that make up fluororesin A, the molecular weight of fluororesin A, etc. For example, the melting point tends to increase as the proportion of unit u1 (described later) increases.

[0034] Examples of fluororesin A include the following, depending on the manufacturing method: Fluororesin A1: A fluorine-containing polymer having a functional group f derived from at least one selected from the group consisting of monomers, chain transfer agents, and polymerization initiators used in the production of the polymer (hereinafter also referred to as "fluorine-containing polymer A1"). Fluororesin A2: A fluororesin in which functional groups f are introduced into a fluororesin that does not have functional groups f by surface treatment such as corona discharge treatment or plasma treatment. Fluororesin A3: A fluororesin obtained by graft polymerization of a monomer having a functional group f onto a fluororesin that does not have a functional group f.

[0035] For the following reasons, fluorine-containing Polymer A1 is preferred as the fluororesin A. In fluorine-containing polymer A1, functional group f is present on at least one of the terminal groups and pendant groups of the main chain, resulting in remarkably excellent adhesion to inorganic fibers. The functional group f in fluororesin A2 is unstable because it was formed by surface treatment, and it tends to disappear over time.

[0036] If the functional group f in fluorine-containing polymer A1 originates from the monomer used in the production of fluorine-containing polymer A1, then fluorine-containing polymer A1 can be produced by the following method (1). In this case, the functional group f is present in the monomer unit formed by the polymerization of monomers during production. Method (1): When producing fluorine-containing polymer A1 by polymerization of fluorine-containing monomers, monomers having a functional group f are copolymerized.

[0037] If the functional group f in fluorine-containing polymer A1 originates from the chain transfer agent used in the production of fluorine-containing polymer A1, then fluorine-containing polymer A1 can be produced by the following method (2). In this case, the functional group f exists as a terminal group of the main chain of fluorine-containing polymer A1. Method (2): A fluorine-containing polymer A1 is produced by polymerization of a fluorine-containing monomer in the presence of a chain transfer agent having a functional group f. Examples of chain transfer agents having a functional group f include acetic acid, acetic anhydride, methyl acetate, ethylene glycol, and propylene glycol.

[0038] If the functional group f in fluorine-containing polymer A1 originates from the polymerization initiator used in the production of fluorine-containing polymer A1, then fluorine-containing polymer A1 can be produced by the following method (3). In this case, the functional group f exists as a terminal group of the main chain of fluorine-containing polymer A1. Method (3): A fluorine-containing polymer A1 is produced by polymerization of a fluorine-containing monomer in the presence of a polymerization initiator such as a radical polymerization initiator having a functional group f. Examples of radical polymerization initiators having a functional group f include di-n-propyl peroxydicarbonate, diisopropyl peroxycarbonate, tert-butyl peroxyisopropyl carbonate, bis(4-tert-butylcyclohexyl) peroxydicarbonate, and di-2-ethylhexyl peroxydicarbonate.

[0039] If the functional group f in the fluorine-containing polymer A1 is derived from two or more of the monomers, chain transfer agents, and polymerization initiators used in the production of the fluorine-containing polymer A1, the fluorine-containing polymer A1 can be produced by using two or more of the above methods (1) to (3) in combination.

[0040] As the fluorine-containing polymer A1, the fluorine-containing polymer A1 having a monomer-derived functional group f, produced by method (1), is preferred because it is easy to control the content of the functional group f and easy to adjust the adhesion to inorganic fibers.

[0041] Preferred monomers having a functional group f include monomers having a carboxyl group, monomers having an acid anhydride group, monomers having a hydroxyl group, and monomers having an epoxy group. Furthermore, these monomers having a functional group f are preferably non-fluorine monomers. Examples of monomers having a carboxyl group include maleic acid, itaconic acid, citraconic acid, and undecylenic acid. Monomers having an acid anhydride group include itaconic anhydride (hereinafter also referred to as "IAH"), citraconic anhydride (hereinafter also referred to as "CAH"), 5-norbornene-2,3-dicarboxylic acid anhydride (hereinafter also referred to as "NAH"), and maleic anhydride. Examples of monomers having a hydroxyl group include hydroxybutyl vinyl ether, and examples of monomers having an epoxy group include glycidyl vinyl ether. However, monomers having the functional group f are not limited to these examples. Furthermore, two or more monomers having the functional group f may be used in combination.

[0042] As a fluorine-containing polymer A1 having a functional group f derived from a monomer, the following fluorine-containing polymer A11 is particularly preferred due to its remarkably excellent adhesion to inorganic fibers. Fluorine-containing polymer A11: A fluorine-containing copolymer having units based on TFE or CTFE (hereinafter also referred to as "unit u1"), units based on cyclic hydrocarbon monomers having acid anhydride groups (hereinafter also referred to as "acid anhydride group-containing cyclic hydrocarbon monomers") (hereinafter also referred to as "unit u2"), and units based on fluorine-containing monomers (excluding TFE and CTFE) (hereinafter also referred to as "unit u3"). Here, the acid anhydride group of unit u2 corresponds to the functional group f.

[0043] Examples of acid anhydride group-containing cyclic hydrocarbon monomers constituting unit u2 include IAH, CAH, NAH, and maleic anhydride. Two or more acid anhydride group-containing cyclic hydrocarbon monomers may be used in combination.

[0044] Preferred cyclic hydrocarbon monomers containing acid anhydride groups are IAH, CAH, and NAH. Using IAH, CAH, or NAH allows for the easy production of fluorine-containing copolymer A11 having acid anhydride groups without requiring the special polymerization method necessary when using maleic anhydride (see Japanese Patent Publication No. 11-193312). As acid anhydride group-containing cyclic hydrocarbon monomers, IAH and NAH are preferred due to their remarkably excellent adhesion to inorganic fibers.

[0045] Examples of fluorine-containing monomers that constitute unit u3 include fluoroolefins (excluding TFE and CTFE), fluorine-containing compounds having a ring structure, PAVE, FAE, compound (3), compound (4), and compound (5). As fluorine-containing monomers constituting unit u3, examples include fluoroolefins, fluorine-containing compounds having a ring structure, PAVE, FAE, compound (3), compound (4), and compound (5), which are the same compounds as those exemplified above as fluorine-containing monomers constituting fluororesins. The same applies to preferred embodiments. PAVE and FAE are preferred as fluorine-containing monomers constituting unit u3, from the viewpoint of mechanical properties, high elasticity, and moldability.

[0046] The preferred proportions of each unit in the fluorine-containing polymer A11 are as follows. The proportion of unit u1 is preferably 90 to 99.89 mol%, more preferably 95 to 99.47 mol%, and even more preferably 96 to 98.95 mol%, relative to the sum of units u1, u2, and u3. The proportion of unit u2 is preferably 0.01 to 3 mol%, more preferably 0.03 to 2 mol%, and even more preferably 0.05 to 1 mol%, relative to the sum of units u1, u2, and u3. The proportion of unit u3 is preferably 0.1 to 9.99 mol%, more preferably 0.5 to 9.97 mol%, and even more preferably 1 to 9.95 mol%, relative to the sum of units u1, u2, and u3.

[0047] In addition to units u1 to u3, the fluorine-containing polymer A11 may also have units based on non-fluorine monomers (excluding cyclic hydrocarbon monomers containing acid anhydride groups) (hereinafter also referred to as "unit u4"). The preferred proportions of each unit when unit u4 is an ethylene unit are as follows: The proportion of unit u1 is preferably 25 to 80 mol%, more preferably 40 to 65 mol%, and even more preferably 45 to 63 mol%, relative to the sum of units u1, u2, u3, and u4. The proportion of unit u2 is preferably 0.01 to 5 mol%, more preferably 0.03 to 3 mol%, and even more preferably 0.05 to 1 mol%, relative to the sum of units u1, u2, u3, and u4. The proportion of unit u3 is preferably 0.2 to 20 mol%, more preferably 0.5 to 15 mol%, and even more preferably 1 to 12 mol%, relative to the sum of units u1, u2, u3, and u4. The proportion of unit u4, i.e., ethylene units, is preferably 20 to 75 mol%, more preferably 35 to 50 mol%, and even more preferably 37 to 55 mol%, relative to the sum of units u1, u2, u3, and u4.

[0048] If the proportion of unit u1 is within the aforementioned range, the flame retardancy, chemical resistance, etc. of the molded article will be remarkably excellent. If the proportion of unit u2 is within the aforementioned range, the amount of acid anhydride groups becomes appropriate, resulting in significantly superior adhesion to inorganic fibers. If the proportion of unit u3 is within the aforementioned range, the moldability is remarkably excellent. The proportion of each unit can be calculated by melt NMR analysis, fluorine content analysis, infrared absorption spectroscopy, etc., of the fluorine-containing polymer A11.

[0049] In fluorine-containing polymer A11, some of the acid anhydride groups in unit u2 undergo hydrolysis, resulting in the inclusion of units based on dicarboxylic acids (such as itaconic acid, citraconic acid, 5-norbornene-2,3-dicarboxylic acid, and maleic acid) corresponding to acid anhydride group-containing cyclic hydrocarbon monomers. In this case, the proportion of units based on dicarboxylic acids corresponding to acid anhydride group-containing cyclic hydrocarbon monomers shall be included in the proportion of unit u2.

[0050] Examples of fluorine-containing copolymer A11 include copolymers having TFE units, NAH units and PPVE units, copolymers having TFE units, IAH units and PPVE units, copolymers having TFE units, CAH units and PPVE units, copolymers having TFE units, IAH units and HFP units, copolymers having TFE units, CAH units and HFP units, copolymers having TFE units, IAH units, PFBE units and ethylene units, copolymers having TFE units, CAH units, PFBE units and ethylene units, copolymers having TFE units, IAH units, PFEE units and ethylene units, copolymers having TFE units, CAH units, PFEE units and ethylene units, copolymers having TFE units, IAH units, HFP units, PFBE units and ethylene units, and the like.

[0051] Fluororesins can be manufactured by conventional methods. For example, fluororesins can be produced by polymerization of monomer components containing at least a fluorine-containing monomer. The monomer components may further contain non-fluorine monomers and monomers having a functional group f, as needed. Polymerization methods include bulk polymerization, solution polymerization using organic solvents (fluorinated hydrocarbons, chlorinated hydrocarbons, fluorinated chlorinated hydrocarbons, alcohols, hydrocarbons, etc.), suspension polymerization using an aqueous medium and, if necessary, a suitable organic solvent, and emulsion polymerization using an aqueous medium and an emulsifier, with solution polymerization being preferred.

[0052] (Inorganic fibers) The inorganic fibers contained in the resin composition of the present invention have at least a portion of their surface treated with a sizing agent. Therefore, the inorganic fibers have advantages such as being easily mixed with fluororesin during the manufacturing of the resin composition. The sizing treatment may be applied to the entire surface of the inorganic fibers, or to only a portion of the surface.

[0053] The sizing agent contains a resin such as a thermosetting resin or a thermoplastic resin, and may optionally contain components such as a curing agent, solvent, dispersant, or silane coupling agent. The resin contained in the sizing agent is not particularly limited. Examples of resins with heat resistance include phenolic resins, melamine resins, bismaleimide resins, unsaturated polyester resins, epoxy resins, polyimide resins, and fluororesins. Among these, bismaleimide resins, epoxy resins, polyimide resins, and fluororesins are preferred, with polyimide resins being more preferred.

[0054] When the resin contained in the sizing agent is a curable resin such as a thermosetting resin, the inorganic fibers sized with the sizing agent usually contain cured resin material on their sized surface. When the resin contained in the sizing agent is a thermoplastic resin, the inorganic fibers sized with the sizing agent usually contain thermoplastic resin on their sized surface. The mass loss of inorganic fibers due to heat treatment is thought to be mainly due to the disappearance of the cured resin material or thermoplastic resin on the surface of the inorganic fibers.

[0055] The mass loss rate of the inorganic fiber, calculated by the following method, is 3% or less, preferably 2.5% or less, and more preferably 2.0% or less. If the mass loss rate is below the upper limit of the above range, the heat resistance of the inorganic fiber will be excellent and the mechanical properties will be good. A smaller mass loss rate is preferable, and there is no particular limit to the lower limit of the mass loss rate.

[0056] Method for calculating the mass loss rate: Inorganic fibers are heated in the presence of air at 400°C for 60 minutes, and the mass loss rate is calculated based on the following formula (I). (Mass reduction rate) = ((Mass of inorganic fiber before heating [g]) - (Mass of inorganic fiber after heating [g])) / (Mass of inorganic fiber before heating [g]) × 100 ... (I)

[0057] Examples of inorganic fibers include carbon fibers, graphite fibers, glass fibers, silicon carbide fibers, silicon nitride fibers, alumina fibers, silicon carbide fibers, boron fibers, and metal fibers. Examples of metal fibers include aluminum fibers, brass fibers, and stainless steel fibers. Among the inorganic fibers, glass fibers and carbon fibers are preferred from the viewpoint of mechanical properties. Inorganic fibers may be used in combination of two or more types.

[0058] The type of carbon fiber is not particularly limited. Examples include pitch-based carbon fiber and polyacrylonitrile-based carbon fiber (PAN-based carbon fiber). Pitch-based carbon fiber may be isotropic or anisotropic. In addition, carbon fibers described in International Publication No. 2013 / 129169 may be used. Furthermore, the method for producing the carbon fiber may be the method described in paragraphs 0028-0033 of International Publication No. 2013 / 129169. The type of glass fiber is not particularly limited. For example, flat glass fibers with an irregular cross-section may be used, or glass fibers with a low dielectric constant may be used from the viewpoint of electrical properties.

[0059] The form of the inorganic fiber is not particularly limited; it may be a short fiber such as milled fiber or chopped fiber, or a long fiber. Furthermore, the cross-sectional shape of the inorganic fiber is not particularly limited. The cross-section may be circular, elliptical, polygonal, or irregular. The form and cross-sectional shape of the inorganic fiber can be appropriately selected according to the desired physical properties.

[0060] The average fiber length of the inorganic fibers is preferably 100 μm to 30 mm, more preferably 150 μm to 25 mm, and even more preferably 200 μm to 20 mm. If the average fiber length of the inorganic fibers is above the lower limit of the above range, it is easier to obtain a molded article with excellent mechanical properties. If the average fiber length of the inorganic fibers is below the upper limit of the above range, it is easier to ensure fluidity during molding.

[0061] The diameter of the inorganic fibers is not particularly limited. Preferably, the diameter of the inorganic fibers is 1 to 15 μm, more preferably 3 to 13 μm, and particularly preferably 5 to 10 μm. If the diameter of the inorganic fibers is above the lower limit of the above range, a molded article with excellent mechanical properties is likely to be obtained. If the diameter of the inorganic fibers is below the upper limit of the above range, the dispersibility of the inorganic fibers is likely to improve.

[0062] The aspect ratio of the fiber length to the diameter of the inorganic fiber is not particularly limited. The aspect ratio is preferably 2 to 1500, more preferably 5 to 1200, and particularly preferably 10 to 100. If the aspect ratio of the fiber length to the diameter of the inorganic fiber is above the lower limit of the above range, a molded article with excellent mechanical properties is more likely to be obtained. If the aspect ratio of the fiber length to the diameter of the inorganic fiber is below the upper limit of the above range, the dispersibility of the inorganic fiber is more likely to improve.

[0063] (Other ingredients) Other components include, but are not limited to, inorganic fillers (excluding inorganic fibers), metal soaps, surfactants, UV absorbers, lubricants, and silane coupling agents.

[0064] (Percentage of each component) In the resin composition of the present invention, the proportion of fluororesin to the total of fluororesin and inorganic fibers is 60 to 95% by mass, preferably 65 to 90% by mass, and more preferably 70 to 85% by mass. If the proportion of fluororesin is above the lower limit of the above range, flame retardancy and chemical resistance are excellent. If the proportion of fluororesin is below the upper limit of the above range, a molded article with excellent mechanical properties and high elasticity can be obtained.

[0065] If the resin composition of the present invention contains other components, it is easier to impart new properties derived from the other components if their proportion is 1% by mass or more relative to the resin composition. The proportion of other components relative to the resin composition is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. If the proportion of other components is below the upper limit of the above range, the effects of the present invention are less likely to be impaired.

[0066] (Method for manufacturing resin compositions) The resin composition can be manufactured by melt-kneading a fluororesin, inorganic fibers, and other components as needed. Alternatively, the resin composition containing the molten fluororesin and inorganic fibers may be extruded into strands, and the strands may be cut with a pelletizer to form pellets.

[0067] The melting and kneading apparatus is not particularly limited. The melting and kneading apparatus may be equipped with a screw that provides a high kneading effect. A single-screw extruder or a twin-screw extruder is preferred, a twin-screw extruder is more preferred, and a twin-screw extruder equipped with a screw that provides a high kneading effect is particularly preferred. For a screw with high mixing efficiency, one can select one that provides sufficient mixing without applying excessive shear force. Examples of melting and mixing equipment include the Laboplast Mill mixer (manufactured by Toyo Seiki Seisakusho Co., Ltd.) and the KZW series twin-screw compounding extruder (manufactured by Technovel Co., Ltd.).

[0068] As for the method of supplying inorganic fibers to the melt-mixing apparatus, the inorganic fibers may be added before melt-mixing the fluororesin, or they may be added after melt-mixing the fluororesin. However, from the viewpoint of mechanical properties, it is preferable to add them after melt-mixing the fluororesin. When other components are to be included in the resin composition, these components may be added before melting and kneading the fluororesin, or they may be added after melting and kneading the fluororesin.

[0069] The temperature during the melting and kneading of the fluororesin should be above the melting point of the fluororesin, preferably between the melting point of the fluororesin + 5°C and the melting point of the fluororesin + 100°C. The extrusion shear rate during melt-kneading of fluororesin and the residence time of the fluororesin in the melt-kneading apparatus are not particularly limited, and known conditions can be appropriately adopted. The extrusion shear rate is preferably set according to the melt viscosity of the fluororesin at the melt-kneading temperature.

[0070] (Mechanism of action) In the resin composition described above, the mass change rate of the inorganic fibers measured under specific conditions is 3% or less, so the inorganic fibers have excellent heat resistance. Therefore, even when melt-molded at high temperatures where the fluororesin exhibits fluidity, the inorganic fibers do not deteriorate easily, and the strength properties and elastic modulus of the molded article are increased. Consequently, a molded article with excellent mechanical properties and high elasticity can be obtained.

[0071] (Application) The resin composition can be used, for example, as a raw material for molded articles. Molded articles made from the resin composition of the present invention have excellent mechanical properties and high elasticity, and are therefore preferably used in applications where these properties are required. Examples of applications for molded products are listed below, but these are just examples, and the applications of molded products are not limited to those listed below.

[0072] Applications of the molded articles include housings for portable electronic devices, coupling members for portable electronic devices, sliding members, three-dimensional circuit components, gears, actuators, pistons, bearings, aircraft interior materials, bushings, tubes (for fuel, etc.), hoses, tanks, seals, wires, insulating coatings for electric wires (wires, cables, etc.), films, sheets, bottles, and fibers. In particular, portable electronic devices are held in the hand and are prone to being contaminated with liquids such as oils contained in food and cosmetics, beverages, sweat, and sebum. The molded articles of the present invention are resistant to discoloration and deterioration from these contaminants, making them suitable for use as housings and coupling members for portable electronic devices. Examples of portable electronic devices include mobile phones, mobile terminals, laptop computers, tablet computers, radios, cameras, camera accessories, watches, calculators, music players, global positioning system receivers, portable games, hard drives, portable storage devices, portable playback devices, and portable radio receivers.

[0073] Examples of the casing form of a portable electronic device include a back cover, front cover, antenna housing, frame, and backbone. The casing may be a component made of a single component of the molded body of the present invention, or a component made of multiple components. Here, the backbone is a component to which components of the portable electronic device, such as electronics, a microprocessor, a screen, a keyboard, a keypad, an antenna, and a battery socket, are attached. When the housing is located inside a portable electronic device, the housing may not be visible from the outside of the portable electronic device, or it may be partially visible from the outside of the portable electronic device. Housings such as covers for protecting and supporting the internal structure may be exposed to the outside of the portable electronic device.

[0074] Examples of coupling members for portable electronic devices include snap-type connectors between the circuit board, microphone, speaker, display, battery, cover, electrical connector, electronic connector, hinge, antenna, switch, and switch pad of the portable electronic device. The coupling members can be suitably applied to portable electronic devices such as mobile phones, personal digital assistants (PDAs), music storage devices, listening devices, portable DVD players, electric multimeters, portable electronic game consoles, and portable personal computers (e.g., notebook computers).

[0075] Three-dimensional circuit components are parts in which a circuit pattern is formed on the surface of a resin part molded into a three-dimensional shape, and are used as antenna components for portable electronic devices and components for automotive electronic equipment. The method used for forming the circuit pattern is laser direct structuring (LDS), which involves etching the circuit pattern with a laser followed by a plating process. The molded body of the present invention exhibits excellent low dielectric properties and is suitably applicable to three-dimensional circuit components.

[0076] Applications of tubes, hoses, tanks, seals, and wires include those described in International Publication No. 2015 / 182702. Furthermore, applications of tubes and hoses include those for drilling energy resources such as petroleum, natural gas, and shale oil. Among these, tubes for petroleum extraction are preferred. Other preferred applications of tubes include medical catheters equipped with tubes, wire insulation, and piping for analytical instruments.

[0077] Applications of insulating coatings for electric wires include insulating coatings for electric wires or flat copper wires for motor coils, and particularly for flat conductors in drive motors for hybrid electric vehicles (HEVs) and electric vehicles (EVs). A film form is preferred for insulating coatings for flat conductors. Other applications of insulating coatings for electric wires include insulating coatings for downhole cables used in energy resource (petroleum, natural gas, shale oil, etc.) drilling. Among these, insulating coatings for downhole cables used in oil extraction are particularly preferred.

[0078] Applications of the film and sheet include speaker diaphragms, plates for trauma and fractures, insulating paper for various electrical insulating adhesive tapes (such as insulating paper for motors), sealing tapes for petroleum and natural gas pipes, and release films for molding thermosetting and thermoplastic composite materials. Particularly preferred applications of the film include speaker diaphragms equipped with the film, films for wire insulation, flexible printed circuit boards, heat-resistant rolls for office automation equipment, and films for impregnating other fiber composite materials. The film thickness is preferably 1 to 100 μm, more preferably 2 to 80 μm, and even more preferably 5 to 50 μm. If the film thickness is above the lower limit of the above range, the strength of the film is improved. If the film thickness is below the upper limit of the above range, the handling of the film in the next process is excellent. Applications of the fibers include protective clothing and various filters.

[0079] Examples of molding methods include injection molding, extrusion molding, co-extrusion molding, blow molding, compression molding, transfer molding, and film molding. However, the molding method is not limited to these examples. [Examples]

[0080] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description. Examples 3, 4, 7 8 is an example, Examples 1 and 5 are for reference only. Examples 2 and 6 are comparative examples.

[0081] <Measurement method> (Content of functional group f) The proportion of monomer units containing the functional group f in the fluororesin was determined by the infrared absorption spectroscopy analysis described below. A 200 μm film was obtained by press molding of fluororesin. In the infrared absorption spectrum of the film, the absorbance of the absorption peak originating from monomer units having the functional group f in the fluororesin was measured, and the proportion (mol%) of monomer units having the functional group f was determined. In the infrared absorption spectrum, the absorption peaks for both IAH and NAH units in fluororesin are 1778 cm⁻¹. -1 It appears there. The absorbance of this absorption peak was measured, and the molar extinction coefficients of IAH and NAH were 20810 mol. -1 ·l·cm -1 The proportion (mol%) of IAH units or NAH units was determined using the formula. If the above proportion is a (mol%), then the main chain carbon number is 1 × 10 6 The number of functional groups f (acid anhydride groups) per individual is [a × 10 6 It is calculated as [ / 100] units.

[0082] (Melting point) Using a differential scanning calorimeter (DSC device, manufactured by Seiko Instruments), the melting peak was recorded when the polymer was heated at a rate of 10°C / min, and the temperature corresponding to the maximum value was defined as the melting point.

[0083] (Melting flow rate) Using a melt indexer (manufactured by Technoseven Co., Ltd.), the mass of polymer flowing out of a nozzle with a diameter of 2 mm and a length of 8 mm over 10 minutes under conditions of 297°C and a load of 49 N was measured.

[0084] (mass reduction rate) Using a Seiko Instruments TGDTA7200, 12 mg of inorganic fiber was placed in an aluminum pan, and the temperature was raised to 400°C at a rate of 10°C / min in an air atmosphere, and then held at 400°C for 60 minutes. The mass after heating at 400°C for 60 minutes was measured, and the mass loss rate was calculated using the following formula I. Mass reduction rate [%] = ((Mass of inorganic fiber before heating [g]) - (Mass of inorganic fiber after heating [g])) / (Mass of inorganic fiber before heating [g]) × 100 ... Equation I

[0085] (Preparation of injection-molded parts for evaluation) Using an injection molding machine (FANUC ROBOSHOT α-50C), the resin composition was injection molded at a mold temperature of 100°C to obtain an evaluation injection-molded body with a thickness of 4.0 mm. The cylinder temperature of the injection molding machine was set to 340°C in Examples 1-4 and to 290°C in Examples 5-8.

[0086] (Tensile test) For the injection-molded parts used for evaluation, tensile strength [MPa] and tensile elongation [%] were measured using TENSILON (manufactured by A&D Company, Limited, model: RTF-1350) in accordance with JIS K7161, with a load cell rating of 10kN, a chuck distance of 115mm, and a speed of 50mm / min.

[0087] (Bending test) A test specimen measuring 80 mm in length and 10 mm in width was cut from the evaluation injection-molded body. The bending strength [MPa] and flexural modulus [GPa] of the test specimen were measured using a TENSILON (A&D, RTF-1350) in accordance with JIS K7171, with a load cell rating of 10 kN, a support distance of 64 mm, and a speed of 2 mm / min.

[0088] (Impact resistance) A test specimen measuring 80 mm in length and 10 mm in width was cut from the evaluation injection-molded body. A notch was made at a height of 40 mm in the evaluation injection-molded body to obtain the test specimen. The Izod impact strength [J / m] of the test specimen was measured using an Izod test apparatus (manufactured by Toyo Seiki Seisakusho Co., Ltd.) under the following conditions: hammer capacity 2.75 J, hammer load 13.97 N, distance from axis to center of gravity 10.54 cm, and distance from axis to point of impact 33.5 cm. The measurement was performed at 23°C.

[0089] <Raw materials> (Fluororesin 1) A fluororesin 1 lacking functional group f was purchased and used. Fluororesin 1 contained TFE units and PPVE units, with TFE units / PPVE units = 98 / 2 (mol%). The melting point of fluororesin 1 was 305°C, and the melt flow rate was 36 g / 10 min.

[0090] (Fluororesin 2) Fluororesin 2 was obtained by synthesis in the same manner as in Example 5 of International Publication No. 2015 / 182702. Fluororesin 2 contained TFE units, PPVE units, and NAH units, with TFE units / PPVE units / NAH units = 97.9 / 2.0 / 0.1 (mol%). The melting point of fluororesin 2 was 300°C, and the melt flow rate was 22 g / 10 min. Furthermore, the content of functional group f was found to be 1 × 10¹⁶ carbon atoms in the main chain of fluororesin 2. 6 There were 1000 for each individual.

[0091] (Fluororesin 3) A fluororesin 3 lacking functional group f was purchased and used. Fluororesin 3 contained TFE units, ethylene units, and PFBE units, with a molar ratio of TFE units / ethylene units / PFBE units = 54 / 46 / 2. The melting point of fluororesin 3 was 260°C, and the melt flow velocity was 28.8 g / 10 min.

[0092] (Fluororesin 4) Fluororesin 4 was obtained by synthesis in the same manner as in Example 4 of International Publication No. 2015 / 182702. Fluororesin 4 contained TFE units, ethylene units, PFEE units, and IAH units, with a molar ratio of TFE units / ethylene units / PFEE units / IAH units = 60 / 40 / 2.2 / 0.5. The melting point of fluororesin 4 was 240°C, and the melt flow rate was 17 g / 10 min. Furthermore, the content of functional group f was such that the main chain carbon number of fluororesin 4 was 1 × 10⁶. 6 There were 1000 for each individual.

[0093] (Carbon fiber 1) ZOLTEC We purchased the company's "PXCA0250-83" and used it as carbon fiber 1. The fiber length of carbon fiber 1 was 5.5 mm, and the mass change rate when heated at 400°C for 60 minutes was 0.1%.

[0094] (Carbon fiber 2) We purchased ZOLTEK's "PXCA0250-45" and used it as carbon fiber 2. The fiber length of carbon fiber 2 was 5.5 mm, and the mass change rate when heated at 400°C for 60 minutes was 3.9%.

[0095] <Examples 1-4> Fluororesin was fed into the base of the screw of a twin-screw extruder (Technovel Co., Ltd., KZW15TW-45MG-NH(-1100), screw diameter: 15mmΦ, L / D: 45) using a feeder, and carbon fiber was fed into the middle of the twin-screw extruder barrel using a side feeder, according to the mixing ratios shown in Table 1. The mixture was kneaded under the following conditions: feed rate of 1.5 kg / hour, screw rotation speed: 100 rpm, cylinder, die, and head set temperatures: C1=300℃, C2=320℃, C3=340℃, C4=340℃, C5=340℃, C6=340℃, D=340℃. The strands extruded from the die tip were cooled in a water bath and cut with a pelletizer to obtain pellets of the resin composition. The measurement results for each example are shown in Table 1.

[0096] <Examples 5-8> Except for the set temperatures of the cylinder, die, and head: C1=285°C, C2=285°C, C3=285°C, C4=285°C, C5=285°C, C6=285°C, and D=290°C, pellets of resin compositions with the blending ratios shown in Table 1 were obtained in the same manner as in Examples 1 to 4. The measurement results for each example are shown in Table 1.

[0097] [Table 1]

[0098] The molded articles of the resin compositions in Examples 1, 3, and 4 exhibited higher tensile strength and flexural strength, and superior mechanical properties compared to Example 2. Furthermore, their flexural modulus was also higher than that of Example 2, resulting in highly elastic molded articles. Similarly, the molded articles of the resin compositions in Examples 5, 7, and 8 exhibited superior mechanical properties and high elasticity compared to Example 6. In Examples 3 and 4, which used fluororesin 2 having functional group f, molded articles were obtained that had even higher tensile strength and flexural strength and even better mechanical properties compared to Example 1. Furthermore, in Examples 3 and 4, molded articles were obtained that had higher Izod impact strength and better impact resistance compared to Example 1. In Examples 7 and 8, which used fluororesin 4 having functional group f, molded articles were obtained that had higher Izod impact strength and superior impact resistance compared to Example 6. [Industrial applicability]

[0099] According to the present invention, a resin composition that yields a molded article with excellent mechanical properties and high elasticity is provided, as well as a molded article with excellent mechanical properties and high elasticity. Furthermore, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2021-116990, filed on July 15, 2021, are incorporated herein by reference as disclosure of the present invention.

Claims

1. A resin composition comprising a melt-mold fluororesin and inorganic fibers, The ratio of the fluororesin to the total of the fluororesin and the inorganic fibers is 60 to 95% by mass. The fluororesin has a functional group selected from the group consisting of a carbonyl group-containing group, a hydroxyl group, an epoxy group, an amide group, an amino group, and an isocyanate group. The inorganic fiber is an inorganic fiber in which at least a portion of its surface has been treated with a sizing agent. A resin composition wherein the mass loss rate of the inorganic fiber, calculated by the following method, is 3% or less. Method for calculating the mass loss rate: Inorganic fibers are heated in the presence of air at 400°C for 60 minutes, and the mass loss rate is calculated based on the following formula (I). Mass reduction rate (%) = ((Mass of inorganic fiber before heating [g]) - (Mass of inorganic fiber after heating [g])) / (Mass of inorganic fiber before heating [g]) × 100 ... (I)

2. The resin composition according to claim 1, wherein the resin composition further comprises components other than the fluororesin and the inorganic fibers, and the content of such components is 20% by mass or less relative to the resin composition.

3. The resin composition according to claim 1, wherein the inorganic fiber is a glass fiber or a carbon fiber.

4. The resin composition according to claim 1, wherein the average fiber length of the inorganic fibers is 100 μm to 30 mm.

5. The resin composition according to claim 1, wherein the fluororesin is a polymer having units based on tetrafluoroethylene, a copolymer having units based on tetrafluoroethylene and units based on ethylene, a copolymer having units based on chlorotrifluoroethylene and units based on ethylene, a copolymer having units based on tetrafluoroethylene and units based on hexafluoropropylene, a copolymer having units based on tetrafluoroethylene and units based on a compound represented by the following formula (1), or a copolymer having units based on tetrafluoroethylene, units based on a compound represented by the following formula (2), and units based on ethylene. CF ２ =CFOR ｆ１ ・・・(1) CH ２ =CX １ (CF ２ ) ｐ X ２ ・・・(2) however, In formula (1), R ｆ１ This is a perfluoroalkyl group having 1 to 10 carbon atoms, which may contain etheric oxygen atoms between carbon atoms. In formula (2), X １ is a hydrogen atom or a fluorine atom, p is an integer from 2 to 10, and X ２ is a hydrogen atom or a fluorine atom.

6. The resin composition according to claim 5, wherein the fluororesin is a copolymer having units based on tetrafluoroethylene and units based on ethylene, a copolymer having units based on tetrafluoroethylene and units based on a compound represented by formula (1), or a copolymer having units based on tetrafluoroethylene, units based on a compound represented by formula (2), and units based on ethylene.

7. The resin composition according to claim 5, wherein the fluororesin is further a polymer having units based on monomers having functional groups selected from the group consisting of carbonyl group-containing groups, hydroxyl groups, epoxy groups, amide groups, amino groups, and isocyanate groups.

8. The resin composition according to claim 7, wherein the polymer having units based on the monomer having the functional group is a polymer having units based on a monomer having a carboxyl group, an acid anhydride group, a hydroxyl group, or an epoxy group.

9. A method for producing the resin composition according to any one of claims 1 to 8, A manufacturing method comprising melt-kneading the fluororesin and the inorganic fibers.

10. A molded article obtained by molding a resin composition according to any one of claims 1 to 8.

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