Resin composition and molded article

Abstract

Provided are a resin composition capable of producing a molded article having enhanced durability, and a molded article including the resin composition.SOLUTION: The resin composition contains a semi-aromatic polyamide having a structural unit represented by formula (1), a glass fiber having a flat cross-sectional shape, and a carbodiimide. In Formula (1), Ar1 represents a phenylene or naphthylene group, and a plurality of Ar1 contained in the semi-aromatic polyamide may be the same as or different from each other. P is an integer of 4 to 12. [Chemical Formula 1] SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a resin composition and a molded article. [Background technology]

[0002] Polyamides have excellent abrasion resistance and strength and are widely used as molding materials for various components such as machine parts. Patent Document 1 discloses a resin composition for engine support members, which contains two types of polyamide resins with different crystallinity, a fibrous filler, and a heat stabilizer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-2205 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a demand for further improvement in the durability of molded articles containing conventional resin compositions containing polyamide resin and glass fiber. The present disclosure has been made in consideration of the above circumstances, and aims to provide a resin composition that can be used to produce a molded article with improved durability, and a molded article containing this resin composition. [Means for solving the problem]

[0005] In order to solve the above problems, the present disclosure includes the following aspects.

[0006] [1] A resin composition comprising a semi-aromatic polyamide having a structural unit represented by the following formula (1), glass fibers having a flat cross-sectional shape, and a carbodiimide:

[0007] [ka] [In formula (1), Ar 1 represents a phenylene group or a naphthylene group, and the plurality of Ar 1 may be the same or different, and p is an integer of 4 to 12.

[0008] [2] The resin composition according to [1], wherein the aspect ratio of the cross section perpendicular to the length direction of the flat glass fiber is 1.3 / 1 or more and 20 / 1 or less.

[0009] [3] The resin composition according to [1] or [2], wherein the carbodiimide is a water-soluble carbodiimide.

[0010] [4] The semi-aromatic polyamide is Ar 1 The resin composition according to any one of [1] to [3], which is a semi-aromatic polyamide having a structural unit represented by formula (1) in which represents a 1,4-phenylene group and p is 9 or 10.

[0011] [5] The resin composition according to any one of [1] to [4], wherein the content of the carbodiimide is 0.03 mass % or more and 20 mass % or less relative to the total mass of the resin composition. [6] The content of the glass fiber having a flat cross section relative to the total mass of the resin composition 5 The resin composition according to any one of [1] to [5], wherein the content is from 100% by mass to 60% by mass. [7] The resin composition according to any one of [1] to [6], which is a resin composition for molding gears.

[0012] [8] A molded article comprising the resin composition according to any one of [1] to [7]. [9] The molded article according to [8], which is a gear. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to provide a resin composition that can be used to produce a molded article with improved durability, and a molded article that includes this resin composition. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a schematic diagram showing an example of a glass fiber having a flat cross-sectional shape. [Figure 2] FIG. 1 is a photographed plan view of an example of a gear manufactured in an example. DETAILED DESCRIPTION OF THE INVENTION

[0015] (Resin composition) One embodiment of the resin composition contains a semi-aromatic polyamide having a structural unit represented by formula (1), glass fibers having a flat cross-sectional shape, and carbodiimide.

[0016] <Semi-aromatic polyamide> The semi-aromatic polyamide in this embodiment has a structural unit represented by the following formula (1).

[0017] [ka] [In formula (1), Ar 1 represents a phenylene group or a naphthylene group, and the plurality of Ar 1 may be the same or different, and p is an integer of 4 to 12.

[0018] The semi-aromatic polyamide is a polycondensation product of an aliphatic diamine and an aromatic dicarboxylic acid. The aliphatic diamine may be an aliphatic diamine having 4 to 12 carbon atoms. Examples of aliphatic diamines having 4 to 12 carbon atoms include 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine. The aliphatic diamines may be used alone or in combination of two or more. Examples of aromatic dicarboxylic acids include terephthalic acid, phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, etc. The aromatic dicarboxylic acids may be used alone or in combination of two or more.

[0019] From the viewpoint of excellent durability and heat resistance of the resulting molded article, Ar 1 represents a phenylene group or a naphthylene group, and the plurality of Ar 1 may be the same or different, and p may be 9 or 10 from the viewpoint of being more excellent in low water absorbency.

[0020] From the viewpoint of obtaining a molded article with superior durability and heat resistance, Ar 1 represents a phenylene group or a naphthylene group, and the plurality of Ar 1 may be the same or different, and p may be 10 from the viewpoint of achieving a more excellent effect of improving durability by adding a water-soluble carbodiimide and a more excellent low water absorption.

[0021] The Ar 1 The phenylene group in Ar may be a 1,4-phenylene group or a 1,3-phenylene group. 1 The naphthylene group includes a 2,6-naphthylene group and a 2,7-naphthylene group.

[0022] Preferably, in the formula (1), Ar 1 represents a 1,4-phenylene group, and p may be an integer of 4 to 12. More preferably, in the formula (1), Ar 1 represents a 1,4-phenylene group, and p may be 9 or 10. Particularly preferably, in the formula (1), Ar 1 represents a 1,4-phenylene group, and p may be 10.

[0023] In the semi-aromatic polyamide, the content of the structural unit represented by the formula (1) is preferably 40% or more, more preferably 80% or more, and even more preferably 90% or more, relative to the total number of all structural units in the semi-aromatic polyamide (100%).

[0024] In the semi-aromatic polyamide, the structural unit represented by the formula (1) is Ar 1 represents a phenylene group or a naphthylene group, and the plurality of Ar groups contained in the semi-aromatic polyamide 1 may be the same or different, and the content of structural units in which p is 9 or 10 is preferably 40% or more, more preferably 80% or more, and even more preferably 90% or more, relative to the total number of all structural units in the semi-aromatic polyamide (100%).

[0025] In the semi-aromatic polyamide, the structural unit represented by the formula (1) is Ar 1 The content of structural units in which represents a 1,4-phenylene group and p is 9 or 10 is preferably 40% or more, more preferably 80% or more, and even more preferably 90% or more, relative to the total number of all structural units (100%) in the semi-aromatic polyamide.

[0026] In the semi-aromatic polyamide, the structural unit represented by the formula (1) is Ar 1 The content of structural units in which represents a 1,4-phenylene group and p is 10 is preferably 40% or more, more preferably 80% or more, and even more preferably 90% or more, relative to the total number of all structural units (100%) in the semi-aromatic polyamide.

[0027] The melt mass flow rate (MFR) of the semi-aromatic polyamide, measured in accordance with JIS K 7210 at a test temperature of 330°C and a load of 2160 g, is preferably 150 g / 10 min or less, more preferably 125 g / 10 min or less, and even more preferably 100 g / 10 min or less. In another aspect, the MFR of the semi-aromatic polyamide, measured in accordance with JIS K 7210 at a test temperature of 330°C and a load of 2160 g, is preferably 80 g / 10 min or less, more preferably 50 g / 10 min or less, and even more preferably 30 g / 10 min or less. A resin composition containing a semi-aromatic polyamide having an MFR equal to or less than the above upper limit can produce a molded article having even better durability.

[0028] The MFR of the semi-aromatic polyamide measured in accordance with JIS K 7210 at a test temperature of 330°C and a load of 2160 g may be 5 g / 10 min or more, 10 g / 10 min or more, or 15 g / 10 min or more.

[0029] The upper and lower limits of the MFR of the semi-aromatic polyamides exemplified above can be freely combined.

[0030] The MFR of the semi-aromatic polyamide, measured in accordance with JIS K 7210 at a test temperature of 330°C and a load of 2160 g, may be, for example, 5 g / 10 min or more and 150 g / 10 min or less, 10 g / 10 min or more and 125 g / 10 min or less, or 15 g / 10 min or more and 100 g / 10 min or less. In another aspect, the MFR of the semi-aromatic polyamide, measured in accordance with JIS K 7210 at a test temperature of 330°C and a load of 2160 g, may be, for example, 5 g / 10 min or more and 80 g / 10 min or less, 10 g / 10 min or more and 50 g / 10 min or less, or 15 g / 10 min or more and 30 g / 10 min or less.

[0031] The MFR of the semi-aromatic polyamide can be controlled by appropriately adjusting conditions related to the reaction efficiency of the polycondensation reaction, such as the raw material monomer, catalyst, and reaction time.

[0032] The resin composition of the present embodiment may contain one type of semi-aromatic polyamide, or may contain two or more types of semi-aromatic polyamides. In the resin composition of this embodiment, the content of the semi-aromatic polyamide is, for example, 40% by mass or more, or may be 40% by mass or more and 95% by mass or less, or 50% by mass or more and 90% by mass or less, or 60% by mass or more and 85% by mass or less, relative to the total mass of the resin composition.

[0033] <Glass fiber with a flat cross section> In this embodiment, glass fibers having a flat cross section (hereinafter sometimes abbreviated as flat glass fibers) refer to glass fibers having a non-circular cross section perpendicular to the length direction, such as an ellipse or an egg shape.

[0034] The flat glass fibers can be E-glass, A-glass, C-glass, D-glass, AR-glass, R-glass, S-glass, or a mixture thereof. The glass fibers may be treated with a coupling agent such as a silane-based coupling agent or a titanium-based coupling agent, if necessary. The flat glass fibers may be coated with a thermoplastic resin such as a polyamide resin, a urethane resin, an acrylic resin, or an ethylene / vinyl acetate copolymer, or a thermosetting resin such as an epoxy resin. The glass fibers may be treated with a sizing agent.

[0035] The aspect ratio (major axis / minor axis) of the cross section perpendicular to the longitudinal direction of the flat glass fiber is preferably in the range of 1.3 / 1 or more and 20 / 1 or less, more preferably 2 / 1 or more and 10 / 1 or less, even more preferably 2.2 / 1 or more and 8 / 1 or less, and particularly preferably 2.2 / 1 or more and 6 / 1 or less. The major axis here refers to the longest diameter of the cross section, and the minor axis refers to the shortest diameter of the cross section.

[0036] When the aspect ratio of the cross section is equal to or greater than the lower limit of the preferred range, the flat glass fibers efficiently reinforce the semi-aromatic polyamide. Therefore, excellent mechanical strength can be imparted to a molded article obtained by molding the resin composition. On the other hand, when the aspect ratio of the cross section is equal to or less than the upper limit of the preferred range, the flat glass fibers are easily dispersed in the semi-aromatic polyamide. Furthermore, the flat glass fibers are easy to handle during the production of the resin composition.

[0037] The flat glass fibers are observed under a scanning electron microscope (1000x magnification) and the number average values ​​of the measured values ​​for 50 flat glass fibers are used as the major axis and minor axis of the cross section. The major axis of the cross section is preferably 16 μm or more and 60 μm or less, more preferably 20 μm or more and 40 μm or less, and the minor axis of the cross section is preferably 4 μm or more and 20 μm or less, more preferably 5 μm or more and 15 μm or less.

[0038] The major and minor diameters of the cross section of the flat glass fiber in the resin composition or molded article are hardly changed by melt-kneading, and are usually the same as the major and minor diameters of the cross section of the flat glass fiber before melt-kneading.

[0039] FIG. 1 is a schematic diagram showing an example of a flat glass fiber. 1, the flat glass fiber 10 is defined by a fiber length L, a cross section S perpendicular to the length direction, and a major axis a and a minor axis b of the cross section S. The shape of the cross section S is elliptical.

[0040] The weight average fiber length of the flat glass fibers in the resin composition may be 300 μm or more and 700 μm or less, or 400 μm or more and 600 μm or less. When the weight-average fiber length of the flat glass fibers is equal to or greater than the above-mentioned lower limit, the durability of the molded article obtained by molding the resin composition is likely to be improved. On the other hand, when the weight-average fiber length of the flat glass fibers is equal to or less than the above-mentioned upper limit, the reinforcement of the semi-aromatic polyamide by the flat glass fibers is efficiently carried out.

[0041] [Method for measuring weight average fiber length of glass fibers in resin composition] The resin composition is heated in an air atmosphere to remove the resin components, obtaining an ashing residue containing glass fibers. The ashing residue is mixed with ethylene glycol to obtain a sample solution. Next, a particle shape image analyzer is used to image each glass fiber in a solution obtained by diluting the sample solution five times with ethylene glycol. The imaged glass fibers are observed, and their longitudinal lengths are read as the fiber lengths. The fiber lengths of 10,000 glass fibers are measured, and the arithmetic mean value of the fiber lengths obtained is calculated. This value is used as the weight-average fiber length of the glass fibers.

[0042] The resin composition of the present embodiment may contain one type of flat glass fiber, or may contain two or more types of flat glass fibers. In the resin composition of this embodiment, the content of the flat glass fibers is, for example, 5% by mass or more, or may be 5% by mass or more and 60% by mass or less, or 10% by mass or more and 50% by mass or less, or 15% by mass or more and 40% by mass or less, relative to the total mass of the resin composition.

[0043] <Carbodiimide> The carbodiimide in this embodiment may be any carbodiimide having a carbodiimide group (-N=C=N-) in the molecule, and may be a monocarbodiimide having one carbodiimide group in the molecule, or a polycarbodiimide having two or more carbodiimide groups in the molecule.

[0044] The carbodiimide may be an aromatic carbodiimide or an aliphatic carbodiimide, or may be an aromatic monocarbodiimide or an aliphatic monocarbodiimide, or may be an aromatic polycarbodiimide or an aliphatic polycarbodiimide.

[0045] The aromatic polycarbodiimide may be a polymer having a repeating unit composed of a carbodiimide group and an aromatic hydrocarbon in the main chain, and the aliphatic polycarbodiimide may be a polymer having a repeating unit composed of a carbodiimide group and a non-aromatic hydrocarbon in the main chain.

[0046] The repeating structure composed of carbodiimide groups and aromatic hydrocarbons may contain a divalent aromatic hydrocarbon group. Examples of the divalent aromatic hydrocarbon group include divalent aryl groups such as phenylene, naphthylene, and biphenylene, and a divalent aromatic hydrocarbon group having 6 to 14 carbon atoms is preferred. One or more hydrogen atoms in the aromatic hydrocarbon group may be substituted, independently of one another, with a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

[0047] The repeating structure composed of carbodiimide groups and non-aromatic hydrocarbons may contain a divalent aliphatic hydrocarbon group. The divalent aliphatic hydrocarbon group may have any of a linear, branched, or cyclic structure. Examples of the divalent aliphatic hydrocarbon group include divalent saturated aliphatic hydrocarbon groups such as alkylene groups and divalent alicyclic hydrocarbon groups such as cycloalkylene groups, and the group may contain a combination of these structures. The divalent saturated aliphatic hydrocarbon group is preferably a divalent saturated aliphatic hydrocarbon group having 1 to 20 carbon atoms. The divalent alicyclic hydrocarbon group is preferably a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, etc. Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, etc. From the viewpoint of achieving a more excellent effect of improving durability by adding a carbodiimide, the aliphatic polycarbodiimide is preferably linear or branched.

[0048] The carbodiimide group (—N═C═N—) equivalent of the carbodiimide in this embodiment may be 100 g / mol or more and 1000 g / mol or less.

[0049] The carbodiimide may also be a water-soluble carbodiimide that is soluble in water.

[0050] <Water-soluble carbodiimide> A water-soluble carbodiimide is a carbodiimide compound that has a carbodiimide group (-N=C=N-) and a hydrophilic segment in the molecule and is soluble in water. The term "water-soluble compound" used herein refers to a compound that can be dissolved in water at 25° C. at a concentration of 10% by mass or more. As the water-soluble carbodiimide, a carbodiimide compound that can be dissolved in water at 25° C. at a concentration of preferably 20% by mass or more, more preferably 35% by mass or more, is used. Examples of the hydrophilic segment include a structure containing at least one selected from the group consisting of an oxyalkylene group, an acetal structure, an imino group, a hydroxy group, an amino group, an epoxy group, and a carboxy group. The water-soluble carbodiimide may be a monocarbodiimide or a polycarbodiimide, and from the viewpoint of having high reactivity with the semi-aromatic polyamide, the water-soluble carbodiimide is preferably a polycarbodiimide.

[0051] The carbodiimide group (-N=C=N-) equivalent of the water-soluble carbodiimide is preferably 300 g / mol or more, and may be 300 g / mol or more and 600 g / mol or less, or 350 g / mol or more and 500 g / mol or less.

[0052] The carbodiimide used in this embodiment may be a known carbodiimide or a commercially available product, such as Carbodilite (registered trademark) V-02, V-02-L2, SV-02, V-04, or V-10 (all manufactured by Nisshinbo Chemical Inc.), which is a water-soluble type of the Carbodilite (registered trademark) series.

[0053] The resin composition of the present embodiment may contain one type of carbodiimide, or may contain two or more types of carbodiimides. Among the above carbodiimides, it is preferable to use a water-soluble carbodiimide, since it has high reactivity with the semi-aromatic polyamide and water can be used as a medium. In the resin composition of this embodiment, the content of the carbodiimide is, for example, 0.03 mass% or more, or may be 0.03 mass% or more and 2 mass% or less, or 0.05 mass% or more and 1.8 mass% or less, or 0.05 mass% or more and 1 mass% or less, relative to the total mass of the resin composition.

[0054] <Other ingredients> The resin composition of the present embodiment may contain other components that do not fall under any of the above-mentioned semi-aromatic polyamides, flat glass fibers, and carbodiimides, as long as the effects of the present disclosure are not impaired. Examples of other components include fillers other than glass fibers, additives, and resins that do not fall under the category of semi-aromatic polyamides (hereinafter sometimes referred to as "other resins"). The other components may be used alone or in combination of two or more.

[0055] The filler other than the glass fiber may be a fibrous filler or a granular filler, and may be an inorganic filler or an organic filler. Examples of the additives include stabilizers, release agents, antioxidants, heat stabilizers, ultraviolet absorbers, antistatic agents, surfactants, flame retardants, and colorants. Examples of other resins include thermoplastic resins such as polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyphenylene ether, polyetherimide, and fluororesin; and thermosetting resins such as phenolic resin, epoxy resin, polyimide resin, and cyanate resin.

[0056] In the resin composition of this embodiment, the semi-aromatic polyamide having the structural unit represented by the above formula (1), the flat glass fiber, the carbodiimide, and other components are contained so that the total content (mass %) of these components is 100 mass %.

[0057] As described above, in the resin composition of this embodiment, a semi-aromatic polyamide having a structural unit represented by the above-mentioned formula (1) is used in combination with flat glass fibers and a carbodiimide. The carbodiimide has a functional group that can react with the semi-aromatic polyamide. The coexistence of this carbodiimide strengthens the adhesion between the flat glass fibers and the semi-aromatic polyamide at their interfaces. In addition, by employing flat glass fibers, the cross-sectional area of ​​the glass fibers is larger than that of a perfectly circular glass fiber, making the glass fibers less likely to break when a load is applied to a molded body. Furthermore, by employing flat glass fibers, the glass fibers have a long fiber length in the longitudinal direction, making the glass fibers less likely to be pulled out of the molded body when a load is applied to the molded body. Therefore, it is believed that the resin composition of this embodiment improves the durability of the molded body.

[0058] The resin composition of the present embodiment is suitable as a molding material for machine parts such as gears, and is particularly suitable as a resin composition for molding gears, because it can enhance the durability of molded articles.

[0059] The durability of the molded article can be evaluated, for example, using the total number of rotations until the gear breaks in the below-described [Durability Test] as an index. [Durability test] A metal master gear as a driving gear is meshed with the gear to be tested and set in a power absorption gear running test machine specified in JIS B 1759. The test machine is operated under the following conditions: load torque on the gear is 8 N·m, rotation speed is 1000 rpm, no lubrication, temperature is 23°C, and relative humidity is 50% RH, and the total number of rotations until the gear breaks is measured. In this durability test, "breakage" of the gear refers to a state in which power cannot be transmitted from the metal master gear to the gear due to breakage of the gear teeth or the like.

[0060] [Method of producing resin composition] The resin composition of the above-described embodiment can be produced by mixing a semi-aromatic polyamide having a structural unit represented by formula (1), flat glass fibers, a carbodiimide, and, if necessary, other components, such that the total content (% by mass) of the semi-aromatic polyamide, flat glass fibers, carbodiimide, and, if necessary, other components in the target resin composition is 100% by mass.

[0061] One embodiment of the method for producing such a resin composition is a production method including a step (S) of mixing a semi-aromatic polyamide having a structural unit represented by the formula (1), flat glass fibers, and a water-soluble carbodiimide. A suitable method for producing the resin composition of this embodiment is a production method including a step (S1) of selecting a water-soluble carbodiimide as the carbodiimide, pre-mixing flat glass fibers with the water-soluble carbodiimide to prepare a mixture (M) of the flat glass fibers and the water-soluble carbodiimide, and a step (S2) of mixing the mixture (M) with a semi-aromatic polyamide having a structural unit represented by the formula (1).

[0062] In one embodiment of step (S1), an aqueous solution of a water-soluble carbodiimide is mixed with flat glass fibers, and then the mixture is heated to remove water, thereby preparing a mixture (M) of the flat glass fibers and the water-soluble carbodiimide. The concentration of the water-soluble carbodiimide in the aqueous solution of the water-soluble carbodiimide is, for example, 30 to 50 mass %. The mixture (M) is in a solid form, such as a powder form.

[0063] In one embodiment of step (S2), the semi-aromatic polyamide and the mixture (M) prepared in step (S1) are fed into a twin-screw extruder and melt-kneaded to produce a resin composition in a desired shape, such as pellets.

[0064] According to the manufacturing method including the above-mentioned steps (S1) and (S2), a resin composition capable of producing a molded article with improved durability can be easily produced. This is because, in the step (S1), an aqueous solution of a water-soluble carbodiimide is mixed with the flat glass fibers in advance, so that the carbodiimide can be strongly bonded to the surface of the glass fibers. This is thought to further strengthen the adhesion at the interface between the glass fibers to which the carbodiimide is strongly bonded and the semi-aromatic polyamide, thereby further improving the durability of the molded article.

[0065] In another aspect, the present disclosure further includes the following embodiments.

[0066]

[10] A resin composition containing a semi-aromatic polyamide having a structural unit represented by the following formula (1), a glass fiber having a flat cross-sectional shape, and a carbodiimide, Relative to the total mass of the resin composition the content of the semi-aromatic polyamide is 40% by mass or more and 95% by mass or less, preferably 50% by mass or more and 90% by mass or less, and more preferably 60% by mass or more and 85% by mass or less, the content of the glass fibers having a flat cross section is 5% by mass or more and 60% by mass or less, preferably 10% by mass or more and 50% by mass or less, and more preferably 15% by mass or more and 40% by mass or less, A resin composition having a carbodiimide content of 0.03% by mass or more and 2% by mass or less, preferably 0.05% by mass or more and 1.8% by mass or less, and more preferably 0.05% by mass or more and 1% by mass or less.

[0067] [ka] [In formula (1), Ar 1 represents a phenylene group or a naphthylene group, and the plurality of Ar 1 may be the same or different, and p is an integer of 4 to 12.

[0068]

[11] A resin composition containing a semi-aromatic polyamide having a structural unit represented by the following formula (1), a glass fiber having a flat cross-sectional shape, and a carbodiimide, Relative to 100 parts by mass of the semi-aromatic polyamide content, the content of the glass fiber having a flat cross section is 5 parts by mass or more and 160 parts by mass or less, preferably 25 parts by mass or more and 75 parts by mass or less, and more preferably 35 parts by mass or more and 50 parts by mass or less, The resin composition has a carbodiimide content of 0.03 parts by mass or more and 5 parts by mass or less, preferably 0.05 parts by mass or more and 3.5 parts by mass or less, and more preferably 0.1 parts by mass or more and 2 parts by mass or less.

[0069] [ka] [In formula (1), Ar 1 represents a phenylene group or a naphthylene group, and the plurality of Ar 1 may be the same or different, and p is an integer of 4 to 12.

[0070]

[12] The resin composition according to

[10] or

[11] , wherein the mass ratio of the glass fiber having a flat cross section to the carbodiimide is 2.5 / 1 to 2000 / 1, preferably 5 / 1 to 1000 / 1, and more preferably 10 / 1 to 200 / 1.

[0071]

[13] The semi-aromatic polyamide is Ar 1 is a semi-aromatic polyamide having a structural unit represented by formula (1) in which represents a 1,4-phenylene group and p is 9 or 10; the aspect ratio of the cross section perpendicular to the longitudinal direction of the glass fiber having a flat cross section is 1.3 / 1 or more and 20 / 1 or less, preferably 2 / 1 or more and 10 / 1 or less, more preferably 2.2 / 1 or more and 8 / 1 or less, and particularly preferably 2.2 / 1 or more and 6 / 1 or less, The carbodiimide is a water-soluble carbodiimide compound that can be dissolved in water at 25°C at a concentration of 10% by mass or more; It has a carbodiimide group (-N=C=N-) and a hydrophilic segment in the molecule, the hydrophilic segment has a structure containing at least one selected from the group consisting of an oxyalkylene group, an acetal structure, an imino group, a hydroxy group, an amino group, an epoxy group, and a carboxy group, The resin composition according to any one of

[10] to

[12] , which is a polycarbodiimide having a carbodiimide group (—N═C═N—) equivalent of 300 g / mol or more and 600 g / mol or less.

[0072]

[14] The resin composition according to

[13] , wherein the major axis of the cross section perpendicular to the longitudinal direction of the glass fiber having a flat cross section is 16 μm or more and 60 μm or less, preferably 20 μm or more and 40 μm or less.

[15] The resin composition according to any one of

[10] to

[14] , wherein the weight average fiber length of the flat glass fibers in the resin composition is 300 μm or more and 700 μm or less.

[0073] (Molded body) One embodiment of the molded article includes the resin composition of the above-described embodiment. An example of the molded article of this embodiment is a molded article containing the resin composition of the above-described embodiment.

[0074] The method for molding the resin composition into a molded article is not particularly limited, but melt molding is preferred, and examples include extrusion molding, T-die molding, blow molding, and injection molding, and the molding method can be selected depending on the shape of the molded article, etc.

[0075] The molded article of this embodiment can be used in any application to which a resin composition can generally be applied. Examples of the molded article of this embodiment include electrical and electronic components such as connectors, sockets, relay parts, coil bobbins, optical pickups, oscillators, printed wiring boards, circuit boards, semiconductor packages, and computer-related parts; semiconductor manufacturing process-related parts such as IC trays and wafer carriers; home electrical appliance parts such as VTRs, televisions, irons, air conditioners, stereos, vacuum cleaners, refrigerators, rice cookers, and lighting fixtures; lighting fixture parts such as lamp reflectors and lamp holders; audio product parts such as compact discs, laser discs (registered trademark), and speakers; communication equipment parts such as ferrules for optical cables, telephone parts, facsimile parts, and modems; separation claws and heater holders. copier and printer related parts; mechanical parts such as impellers, fan gears, gears, bearings, motor parts and cases; automotive parts such as automotive mechanism parts, engine parts, engine room parts, electrical parts, and interior parts, cooking utensils such as microwave cooking pots and heat-resistant tableware; heat insulation and soundproofing materials such as flooring and wall materials, supporting materials such as beams and pillars, building materials such as roofing materials, civil engineering and construction materials; aircraft, spacecraft, and space equipment parts; radiation facility components such as nuclear reactors, marine facility components, cleaning jigs, optical equipment parts, valves, pipes, nozzles, filters, membranes, medical equipment parts and medical materials, sensor parts, sanitary equipment, sporting goods, leisure goods, and cable ties.

[0076] The molded article of the present embodiment contains the resin composition of the above-described embodiment, and therefore has improved durability. Therefore, the molded article of the present embodiment is particularly suitable for sliding applications, and is particularly suitable for use as a mechanical part such as a gear, and is particularly suitable for use as a gear. Types of gears include spur gears, helical gears, racks, internal gears, worm gears, worm wheel gears, bevel gears, hypoid gears, and the like. [Example]

[0077] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited to the following examples.

[0078] <Production of Resin Composition> The semi-aromatic polyamide, glass fiber, and carbodiimide used were as follows:

[0079] Semi-aromatic polyamide Semi-aromatic polyamide (P1): Ar 1 A semi-aromatic polyamide having a structural unit represented by formula (1), in which is a 1,4-phenylene group and p is 10. Melt mass-flow rate (MFR) 24 g / 10 min. Semi-aromatic polyamide (P2): Ar 1 A semi-aromatic polyamide having a structural unit represented by formula (1), in which is a 1,4-phenylene group and p is 9. MFR: 20 g / 10 min. The MFR of the semi-aromatic polyamide was measured in accordance with JIS K 7210 at a test temperature of 330°C and a load of 2160 g.

[0080] Glass fiber Glass fiber with a flat cross section (flat glass fiber): "CSG3PA-820S" manufactured by Nitto Boseki Co., Ltd., major axis 28 μm, minor axis 7 μm, aspect ratio (major axis / minor axis) 4 / 1, average fiber length 3 mm, silane surface treatment Glass fiber with a circular cross section (circular glass fiber): "T-275H" manufactured by Nippon Electric Glass Co., Ltd., fiber diameter 10 μm, average fiber length 3 mm

[0081] Carbodiimide Carbodiimide (1): Aqueous solution of water-soluble carbodiimide, "Carbodilite SV-02" manufactured by Nisshinbo Chemical Co., Ltd., non-volatile content 40% by mass, carbodiimide group equivalent weight 430 g / mol

[0082] [Method for measuring weight average fiber length of glass fibers in a resin composition in pellet form] Five grams of pellets were heated in a muffle furnace (Yamato Scientific Co., Ltd., FP410) under an air atmosphere at 600°C for six hours to remove the resin, yielding an ashing residue containing glass fibers. 0.3 g of the ashing residue was mixed with 50 mL of ethylene glycol, and the resulting mixture was irradiated with ultrasound for five minutes using an ultrasonic cleaner (VELVO-CLEAR, model number: VS-25) to obtain a sample solution. 5 mL of the sample solution was diluted five-fold with ethylene glycol, and images of individual glass fibers in the solution were taken using a particle shape image analyzer (Beckman Coulter, Inc., "Rapid VUE"). The imaged glass fibers were observed, and their longitudinal lengths were recorded as the fiber lengths. The fiber lengths of 10,000 glass fibers were measured, and the arithmetic mean value of the fiber lengths was calculated. This value was used as the weight-average fiber length of the glass fibers.

[0083] Example 1 After mixing 1.25 parts by mass of carbodiimide (1) with 30 parts by mass of flat glass fibers, the mixture was heated to 120°C to remove water, and 30.5 parts by mass of a mixture (Ma) of flat glass fibers and water-soluble carbodiimide was obtained. 30.5 parts by mass of the resulting mixture (Ma) and 69.5 parts by mass of the semi-aromatic polyamide (P1) were placed in a twin-screw extruder (PCM-30, manufactured by Ikegai Corporation) and melt-kneaded while degassing under conditions of a barrel temperature of 320-350°C, a screw rotation speed of 150 rpm, and a discharge rate of 5 kg / min. The mixture was discharged in the form of strands through a circular nozzle (discharge port), passed through a water-cooled belt conveyor, and pelletized with a strand cutter to obtain a resin composition in the form of pellets. The weight-average fiber length of the glass fibers in the resulting pellets was 448 μm.

[0084] (Comparative Example 1) A pellet-shaped resin composition was obtained in the same manner as in Example 1, except that 30 parts by mass of flat glass fibers alone were used instead of 30.5 parts by mass of the mixture (Ma) and the amount of semi-aromatic polyamide (P1) was changed to 70 parts by mass. The weight average fiber length of the glass fibers in the obtained pellets was 444 μm.

[0085] (Comparative Example 2) Except for changing 30 parts by mass of flat glass fibers to 30 parts by mass of circular glass fibers, a resin composition in pellet form was obtained in the same manner as in Example 1. The weight average fiber length of the glass fibers in the obtained pellets was 408 μm.

[0086] Example 2 Except for changing 69.5 parts by mass of the semi-aromatic polyamide (P2) to 69.5 parts by mass of the semi-aromatic polyamide (P1), a pellet-shaped resin composition was obtained in the same manner as in Example 1. The weight average fiber length of the glass fibers in the obtained pellets was 448 μm.

[0087] (Comparative Example 3) A pellet-shaped resin composition was obtained in the same manner as in Example 2, except that 30 parts by mass of flat glass fibers alone were used instead of 30.5 parts by mass of the mixture (Ma) and the amount of semi-aromatic polyamide (P2) was changed to 70 parts by mass. The weight average fiber length of the glass fibers in the obtained pellets was 444 μm.

[0088] <Gear manufacturing example> The pellet-shaped resin composition was placed in an injection molding machine and injection molded to produce a gear under the following injection conditions: barrel temperature 320-340°C, mold temperature 120°C, back pressure 6 MPa, screw rotation speed 100 rpm, injection pressure 100 MPa, injection speed 30 mm / sec, injection time 6 seconds, dwell pressure 90 MPa, and cooling time 25 seconds. The gear was manufactured to have the following shape: spur gear, module 1, number of teeth 48, pressure angle 20°, reference diameter 48 mm, tip diameter 50 mm, root diameter 45.5 mm, face width 8 mm, transition coefficient 0, and spanning tooth thickness 16.909 (number of spanning teeth 6). An example of the manufactured gear is shown in Figure 2.

[0089] <Evaluation> The manufactured gears were subjected to the following durability test. [Durability test] A metal master gear [material: SCM420 carburized, quenched, and tempered (surface hardened), quench-hardened layer depth 0.8 to 1.2, hardness HRC 55 to 60, gear shape: spur gear, module 1, number of teeth 67, pressure angle 20°, reference circle diameter 67 mm, tip circle diameter 69 mm, root circle diameter 64.5 mm, face width 15 mm, transition coefficient 0, and spanning tooth thickness 23.079 (number of spanning teeth 8)] was installed as the drive gear in a power absorption gear operation test machine specified in JIS B 1759, and the manufactured gear was meshed with it. The manufactured gear was subjected to a load torque of 8 N m, a rotational speed of 1000 rpm, no lubrication, a temperature of 23°C, a relative humidity of 50% RH, and a normal backlash of 0.1 mm. The total number of rotations until the gear broke was measured. The results are shown in Table 1. The "destruction" of the gear refers to a state in which power cannot be transmitted from the metal master gear to the gear due to breakage of the gear teeth or the like.

[0090] [Table 1]

[0091] According to the results of the durability test, Example 1 containing flat glass fibers had improved gear durability compared to Comparative Example 2 containing round glass fibers.

[0092] The durability tests were conducted under high-load conditions with a load torque of 8 N m, demonstrating that the pellet-shaped resin compositions of Examples 1 and 2 are useful molding materials that can be used to produce gears with excellent durability under high-load conditions.

[0093] The configurations and combinations thereof in each embodiment are merely examples, and modifications such as addition, omission, and substitution of configurations are possible within the scope of the spirit of this disclosure. Furthermore, this disclosure is not limited to each embodiment, but is limited only by the claims. [Explanation of symbols]

[0094] 10. Glass fiber

Claims

1. A semi-aromatic polyamide having a structural unit represented by the following formula (1): Glass fibers having a flat cross-sectional shape; Carbodiimide and A resin composition comprising: 【Chemistry 1】 [In formula (1), Ar １ represents a phenylene group or a naphthylene group, and the plurality of Ar groups contained in the semi-aromatic polyamide １ may be the same or different, and p is an integer of 4 to 12.

2. The resin composition according to claim 1, wherein the aspect ratio of the cross section perpendicular to the length direction of the flat glass fiber is 1.3 / 1 or more and 20 / 1 or less.

3. The resin composition according to claim 1 , wherein the carbodiimide is a water-soluble carbodiimide.

4. The semi-aromatic polyamide is a polyamide represented by the formula (1) １ The resin composition according to claim 1, which is a semi-aromatic polyamide having a structural unit in which represents a 1,4-phenylene group and p is 9 or 10.

5. The resin composition according to claim 1, wherein the content of the carbodiimide is 0.03 mass % or more and 20 mass % or less with respect to the total mass of the resin composition.

6. The resin composition according to claim 1, wherein the content of the glass fiber having a flat cross section is 5% by mass or more and 60% by mass or less with respect to the total mass of the resin composition.

7. The resin composition according to claim 1, which is a resin composition for molding gears.

8. A molded article comprising the resin composition according to any one of claims 1 to 7.

9. The molded article according to claim 8, which is a gear.

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