Resin composition, method for producing the same and resin molded body

Abstract

To provide: a resin composition comprising a crystalline polyamide resin and an amorphous polyarylate resin in which the crystallization rate is suppressed and the productivity of a resin molded product can be improved; a method for producing the same; and a resin molded body obtained from the resin composition.SOLUTION: There is provided a resin composition comprising a crystalline polyamide resin and an amorphous polyarylate resin, wherein the cooling crystallization temperature difference (ΔT) calculated from the following expression is 5°C or more. The cooling crystallization temperature difference=(the cooling crystallization temperature of the crystalline polyamide resin)-(the cooling crystallization temperature of the resin composition) (1)SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition containing a crystalline polyamide resin and an amorphous polyarylate resin, which has a suppressed crystallization rate and can improve the productivity of resin molded articles, a method for producing the same, and a resin molded article obtained from the resin composition. [Background technology]

[0002] Resin compositions containing polyamide resins and polyarylate resins are used primarily in the electrical and electronic fields as metal substitutes due to their excellent chemical resistance and moldability. Furthermore, resin materials containing reinforcing materials such as glass fibers are known to improve the mechanical properties of resin materials.

[0003] For example, Patent Document 1 discloses a glass fiber reinforced resin composition comprising 30 to 70 mass% of a mixed resin comprising 10 to 90 mass% of (A) polyarylate resin and 90 to 10 mass% of (B) polyamide resin, further blended with 2 to 30 mass% of (C) glass balloons and 30 to 70 mass% of (D) glass fiber, wherein 70% or more (by mass) of the blended (C) glass balloons are crushed in the glass fiber reinforced resin composition. The document also discloses that the glass fiber reinforced resin composition has excellent mechanical properties and exhibits little deterioration in performance under specific operating temperature and humidity conditions.

[0004] Patent Document 2 discloses a resin composition containing a polyarylate resin (A) and an aliphatic polyamide resin (B), wherein the melting point of the aliphatic polyamide resin (B) is less than 225°C and the mass ratio (A / B) of the polyarylate resin (A) to the aliphatic polyamide resin (B) is 80 / 20 to 20 / 80. The document describes that the resin composition has low water absorption and excellent weather resistance and chemical resistance.

[0005] Furthermore, Patent Documents 3 and 4 describe that a polyamide resin composition containing a semi-aromatic polyamide resin, a polyarylate resin, and a fibrous reinforcing material has excellent creep deformation resistance in a high-temperature environment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-174064 [Patent Document 2] Japanese Patent Publication No. 2020-111672 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-12795 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-15532 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the resin compositions described in Patent Documents 1 to 4 have room for improvement in terms of crystallization rate. Specifically, conventional resin compositions containing a polyamide resin and a polyarylate resin have a high crystallization rate, which causes a problem of easily generating voids in resin molded articles obtained by injection molding or the like. Conventionally, a mold has been adjusted to a high temperature in order to suppress the crystallization rate of the resin composition and prevent voids from being generated in the resin molded article. However, when the mold is heated to a high temperature, it takes a long time to cool, which lengthens the production cycle time of the resin molded article, resulting in a problem of poor productivity of the resin molded article.

[0008] The present invention is intended to solve the above-mentioned problems, and aims to provide a resin composition containing a crystalline polyamide resin and an amorphous polyarylate resin, which has a suppressed crystallization rate and can improve the productivity of resin molded articles, a method for producing the same, and a resin molded article obtained from the resin composition. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above-mentioned problems and have found that the problems can be solved by adjusting the temperature-lowering crystallization temperature of a resin composition containing a crystalline polyamide resin and an amorphous polyarylate resin to be 5°C or more lower than the temperature-lowering crystallization temperature of the crystalline polyamide resin. The present invention was completed through further research based on this finding.

[0010] That is, the present invention provides the following aspects. <1> A resin composition containing a crystalline polyamide resin and an amorphous polyarylate resin, wherein the temperature-lowering crystallization temperature difference (ΔT) calculated by the following formula (1) is 5°C or more. Temperature-reducing crystallization temperature difference = (temperature-reducing crystallization temperature of crystalline polyamide resin) - (temperature-reducing crystallization temperature of resin composition) (1) <2> The crystalline polyamide resin has an endothermic heat (ΔH) resulting from crystallization upon temperature decrease of 10 mJ / mg or more. <1> The resin composition according to claim 1. <3> a mass ratio of the crystalline polyamide resin to the amorphous polyarylate resin (crystalline polyamide resin / amorphous polyarylate resin) of 98 / 2 to 35 / 65; <1> or <2> The resin composition according to claim 1. <4> The crystalline polyamide resin is an aromatic polyamide resin. <1> ~ <3> The resin composition according to any one of the preceding claims. <5> The amorphous polyarylate resin has a carboxyl value of 12 equivalents / ton or more. <1> ~ <4> The resin composition according to any one of the preceding claims. <6> <1> ~ <5> A resin molded article obtained from the resin composition according to any one of the preceding items. <7> The method includes a step of kneading at least the crystalline polyamide resin and the amorphous polyarylate resin so that the temperature-lowering crystallization temperature difference (ΔT) calculated by the formula (1) is 5°C or more. <1> ~ <5> 10. A method for producing the resin composition according to any one of the preceding claims. [Effects of the Invention]

[0011] The resin composition containing the crystalline polyamide resin and amorphous polyarylate resin of the present invention has a slower crystallization rate than conventional resin compositions containing these resins, and therefore, when producing a resin molded article by injection molding or the like, it is possible to suppress the generation of voids in the resin molded article without raising the mold temperature as in the conventional method. As a result, it is possible to produce high-quality resin molded articles and also shorten the production cycle time of resin molded articles, thereby improving the productivity of resin molded articles. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing a method for testing the chemical resistance of a resin molded body. DETAILED DESCRIPTION OF THE INVENTION

[0013] <Resin composition> The resin composition of the present invention is characterized by containing a crystalline polyamide resin and an amorphous polyarylate resin, and having a temperature-lowering crystallization temperature difference (ΔT) calculated by the following formula (1) of 5° C. or more. Temperature-reducing crystallization temperature difference = (temperature-reducing crystallization temperature of crystalline polyamide resin) - (temperature-reducing crystallization temperature of resin composition) (1) The resin composition of the present invention will be described in detail below.

[0014] [Crystalline polyamide resin] The crystalline polyamide resin used in the present invention is not particularly limited as long as it is a crystalline polyamide resin. In the present invention, the term "crystalline polyamide resin" refers to a polyamide resin having a melting point.

[0015] Examples of crystalline polyamide resins include (a) polyamide resins obtained by ring-opening polymerization of lactams such as pyrrolidone, caprolactam, undecalactam, and dodecalactam, (b) polyamide resins obtained by self-condensation of ω-aminocarboxylic acids, and (c) polyamide resins obtained by condensing diamines such as linear saturated aliphatic diamines having 2 to 20 carbon atoms and branched saturated aliphatic diamines having 3 to 20 carbon atoms with dicarboxylic acids such as aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids, as well as copolymers thereof. These crystalline polyamide resins may be used alone or in combination of two or more.

[0016] From the viewpoints of reducing the molding shrinkage rate of the resin molded article and of the chemical resistance of the resin molded article, the crystalline polyamide resin is preferably a crystalline polyamide resin having an endothermic heat (ΔH) resulting from crystallization upon cooling of 10 mJ / mg or more, more preferably a crystalline polyamide resin having an endothermic heat (ΔH) of 30 mJ / mg or more, and even more preferably a crystalline polyamide resin having an endothermic heat (ΔH) of 50 mJ / mg or more. The upper limit of the endothermic heat (ΔH) is not particularly limited, but is usually 150 mJ / mg or less, preferably 110 mJ / mg or less, more preferably 80 mJ / mg or less, and even more preferably 70 mJ / mg or less. In the present invention, the endothermic heat (ΔH) resulting from the crystallization of a crystalline polyamide resin upon cooling means the peak area of ​​the exothermic peak measured using a differential scanning calorimeter (DSC) when the crystalline polyamide resin is heated to 360°C at a heating rate of 30°C / min to melt it, then held at 360°C for 5 minutes, and then cooled to 30°C at a cooling rate of 20°C / min.

[0017] Examples of the crystalline polyamide resin having the endothermic value (ΔH) include polycaproamide (polyamide 6), polytetramethylene adipamide (polyamide 46), polypentamethylene adipamide (polyamide 56), polyhexamethylene adipamide (polyamide 66), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polypentamethylene sebacamide (polyamide 510), polyundecamethylene adipamide (polyamide 116), polyundecamethylene (polyamide 11), polydodecamide (polyamide 12), polybis(4- Examples of suitable terephthalamides include poly(3-methyl-4-aminocyclohexyl)methandodecamide (polyamide PACM12), polybis(3-methyl-4-aminocyclohexyl)methandodecamide (polyamide dimethyl PACM12), polymetaxylylene adipamide (polyamide MXD6), polymetaxylylene sebacamide (polyamide MXD10), polynonamethylene terephthalamide (polyamide 9T), polydecamethylene terephthalamide (polyamide 10T), polyundecamethylene terephthalamide (polyamide 11T), and polyundecamethylene hexahydroterephthalamide (polyamide 11T(H)). Further, examples of copolymers include polyamide 66 / 6, polyamide 6T / 6, polyamide 6T / 12, polyamide 6T / 46, polyamide 6T / 66, polyamide 6T / 610, polyamide 6T / 612, polyamide 6T / 6I, polyamide 6T / 6I / 66, polyamide 6T / M5T (M5: methylpentadiamine), polyamide 6T / TM6T (TM6: 2,2,4- or 2,4,4-trimethylhexamethylenediamine), and polyamide 6T / MMCT (MMC: 4,4'-methylenebis(2-methylcyclohexylamine)). These crystalline polyamide resins may be used alone or in combination of two or more.Of these, from the viewpoint of reducing the molding shrinkage rate of the resin molded body and from the viewpoint of the chemical resistance of the resin molded body, it is preferable to use at least one selected from the group consisting of polyamide 6 (ΔH: 74.6 mJ / mg), polyamide 46 (ΔH: 103.4 mJ / mg), polyamide 9T (ΔH: 56.2 mJ / mg), and polyamide 10T (ΔH: 66.2 mJ / mg), it is more preferable to use at least one selected from the group consisting of polyamide 46, polyamide 9T, and polyamide 10T, and it is even more preferable to use at least one selected from the group consisting of polyamide 9T and polyamide 10T.

[0018] In the resin composition of the present invention, the content of the crystalline polyamide resin is usually 40 to 99 mass %, and from the viewpoint of facilitating the production of a resin composition having a temperature-decreasing crystallization temperature difference (ΔT) of 5°C or more, from the viewpoint of reducing the molding shrinkage rate of a resin molded article, and from the viewpoint of the chemical resistance of the resin molded article, it is preferably 45 to 95 mass %, more preferably 50 to 90 mass %.

[0019] [Amorphous polyarylate resin] The amorphous polyarylate resin used in the present invention is not particularly limited as long as it is an amorphous polyarylate resin. In the present invention, the term "amorphous polyarylate resin" refers to a polyarylate resin that does not exhibit an endothermic peak due to the latent heat of fusion of crystals or an exothermic peak due to the latent heat of crystallization when measured using a differential scanning calorimeter. However, the amorphous polyarylate resin used in the present invention does not include so-called liquid crystal polymers having mesogenic groups.

[0020] Examples of amorphous polyarylate resins include those containing an aromatic dicarboxylic acid component and a dihydric phenol component as constituent components.

[0021] Examples of aromatic dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, chlorophthalic acid, nitrophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, methyl terephthalic acid, 4,4'-biphenyldicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenylisopropylidenedicarboxylic acid, 1,2-bis(4-carboxyphenoxy)ethane, and 5-sodium sulfoisophthalic acid. These aromatic dicarboxylic acid components may be used alone or in combination of two or more. Among these, from the viewpoints of obtaining a resin composition having excellent moldability, obtaining a resin molded article having excellent mechanical properties and chemical resistance, and reducing the molding shrinkage rate of the resin molded article, it is preferable to use at least one selected from the group consisting of terephthalic acid and isophthalic acid, and it is more preferable to use terephthalic acid and isophthalic acid in combination. When terephthalic acid and isophthalic acid are used in combination, the mixing molar ratio of terephthalic acid to isophthalic acid (terephthalic acid / isophthalic acid) is preferably 80 / 20 to 20 / 80 (mol%), more preferably 70 / 30 to 25 / 75 (mol%), and even more preferably 60 / 40 to 30 / 70 (mol%).

[0022] Examples of dihydric phenol components include resorcinol, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-(4-hydroxyphenyl)butane, 2,2-(4-hydroxyphenyl)-4-methylpentane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'- Examples of the dihydric phenol component include dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenylmethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 3,3,5-trimethyl-1,1-bis(4-hydroxyphenyl)cyclohexane. These dihydric phenol components may be used alone or in combination of two or more. Among these, 2,2-bis(4-hydroxyphenyl)propane is preferred from the viewpoints of obtaining a resin composition having excellent moldability, obtaining a resin molded article having excellent mechanical properties and chemical resistance, and reducing the mold shrinkage of the resin molded article.

[0023] The inherent viscosity of the amorphous polyarylate resin is not particularly limited, but from the viewpoint of obtaining a resin molded article having good mechanical properties, it is preferably 0.45 or more, more preferably 0.45 to 0.75, and even more preferably 0.45 to 0.65. In the present invention, the inherent viscosity of the amorphous polyarylate resin is a value calculated from the following formula by measuring the falling speed of a sample solution of the amorphous polyarylate resin dissolved in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 60 / 40 (mass ratio) at a concentration of 1 g / dL and the mixed solvent using an Ubbelohde viscometer at a temperature of 25°C. Inherent viscosity = ln [(drop time of sample solution / drop time of mixed solvent) / resin concentration of sample solution (g / dL)]

[0024] The carboxyl value of the amorphous polyarylate resin is not particularly limited, but is preferably 12 equivalents / ton or more, more preferably 15 to 200 equivalents / ton, from the viewpoint of suppressing deterioration of the mechanical properties of the resin molded article. The carboxyl value of the amorphous polyarylate resin is derived from the terminal carboxylic acid and the carboxylic anhydride bond generated by a side reaction. In the present invention, the carboxyl value of the amorphous polyarylate resin is a value obtained by the following measurement method. 0.30 g of the amorphous polyarylate resin is dissolved in 20 mL of methylene chloride, and phenol red is further added as an indicator to obtain a sample solution. While stirring the obtained sample solution, 0.1 N KOH (ethanol-benzyl alcohol) solution is added dropwise to the sample solution, and the carboxyl value is determined by neutralization titration.

[0025] The method for producing the amorphous polyarylate resin is not particularly limited, and the resin can be produced by known polymerization methods such as solution polymerization, melt polymerization, interfacial polymerization, etc. Among these, the solution polymerization method and the interfacial polymerization method are preferred because they facilitate high molecular weight production and can prevent discoloration due to heat.

[0026] An example of a solution polymerization method is to dissolve a dihydric phenol and an aromatic dicarboxylic acid dihalide in an organic solvent, stir the mixture, and react the mixture at 2 to 80°C. An example of a melt polymerization method is to react a dihydric phenol with an organic carboxylic acid anhydride such as acetic anhydride at 100 to 200°C to obtain a diesterified product of the dihydric phenol, and then heat the mixture to 300 to 360°C under reduced pressure while stirring with the aromatic dicarboxylic acid to carry out an ester exchange reaction, while simultaneously distilling off the organic carboxylic acid by-product. An example of an interfacial polymerization method is to mix an aqueous alkali solution of a dihydric phenol with an organic solvent solution of an aromatic dicarboxylic acid dihalide in the presence of a polymerization catalyst, and stir the mixture at 2 to 80°C.

[0027] In the resin composition of the present invention, the content of the amorphous polyarylate resin is usually 1 to 60 mass %, and from the viewpoint of facilitating the production of a resin composition having a temperature-decreasing crystallization temperature difference (ΔT) of 5°C or more, from the viewpoint of reducing the molding shrinkage rate of a resin molded article, and from the viewpoint of the chemical resistance of the resin molded article, it is preferably 5 to 55 mass %, and more preferably 10 to 50 mass %.

[0028] [Mass ratio of crystalline polyamide resin to amorphous polyarylate resin] The mass ratio of the crystalline polyamide resin to the amorphous polyarylate resin (crystalline polyamide resin / amorphous polyarylate resin) is not particularly limited, but is preferably 98 / 2 to 35 / 65, more preferably 95 / 5 to 40 / 60, and even more preferably 90 / 10 to 50 / 50. By setting the mass ratio of the crystalline polyamide resin to 98% by mass or less, it becomes easier to produce a resin composition having a temperature-decreasing crystallization temperature difference (ΔT) of 5°C or more, and also to obtain a resin molded product with a small molding shrinkage rate. Furthermore, by setting the mass ratio of the crystalline polyamide resin to 35% by mass or more, the crystallization characteristics of the resin composition make it easier to suppress a decrease in the chemical resistance of the resin molded product.

[0029] [Other ingredients] The resin composition of the present invention may contain other resins besides the crystalline polyamide resin and the amorphous polyarylate resin, but preferably does not contain any other resins. The other resins are not particularly limited, but examples include polycarbonate resins, polyester resins, polyphenylene ether resins, polystyrene resins, acrylonitrile-butadiene-styrene resins, and liquid crystal polymers. The polyester resin refers to polyester resins other than the amorphous polyarylate resin.

[0030] The resin composition of the present invention may contain additives such as fillers and stabilizers. Examples of additives include fillers such as glass fiber, talc, swellable clay minerals, silica, alumina, glass beads, and graphite; pigments such as titanium oxide and carbon black; antioxidants, antistatic agents, flame retardants, flame retardant assistants, and compatibilizers. These additives may be contained alone or in combination of two or more. These additives may be added as desired during melt-kneading of the resin composition.

[0031] [Physical properties of resin composition] The resin composition of the present invention has a temperature-decreasing crystallization temperature difference (ΔT) calculated by the following formula (1) of 5° C. or more, and from the viewpoint of further suppressing the crystallization rate of the resin composition, it is preferably 20° C. or more, more preferably 30° C. or more, and even more preferably 50° C. or more. The upper limit of the temperature-decreasing crystallization temperature difference (ΔT) is not particularly limited, but is usually 350° C. or less, preferably 300° C. or less, more preferably 200° C. or less, and even more preferably 100° C. or less. Temperature-reducing crystallization temperature difference = (temperature-reducing crystallization temperature of crystalline polyamide resin) - (temperature-reducing crystallization temperature of resin composition) (1) In the present invention, the temperature-lowering crystallization temperature of a crystalline polyamide resin means the top temperature of the exothermic peak when the crystalline polyamide resin is heated to 360°C at a heating rate of 30°C / min using a differential scanning calorimeter (DSC) to melt it, then held at 360°C for 5 minutes, and then cooled to 30°C at a cooling rate of 20°C / min. In the present invention, the temperature-lowering crystallization temperature of the resin composition means the top temperature of the exothermic peak when the resin composition is heated to 360°C at a heating rate of 30°C / min using a differential scanning calorimeter (DSC) to melt it, then held at 360°C for 5 minutes, and then cooled to 30°C at a cooling rate of 20°C / min.

[0032] [Method of producing resin composition] The method for producing a resin composition of the present invention includes a step of kneading at least a crystalline polyamide resin and an amorphous polyarylate resin so that the temperature-lowering crystallization temperature difference (ΔT) is 5°C or more. The kneading is preferably melt kneading using a twin-screw kneader. The kneading temperature is not particularly limited and may be adjusted appropriately depending on the type of crystalline polyamide resin. For example, when the crystalline polyamide resin is an aliphatic polyamide resin, the kneading temperature is preferably equal to or higher than the melting point (Tm) of the aliphatic polyamide resin, and preferably lower than (Tm + 100°C). If the kneading temperature is lower than the melting point of the aliphatic polyamide resin, the load on the kneader increases, which may result in problems such as venting. Furthermore, when the crystalline polyamide resin is a semi-aromatic polyamide resin (meaning a polyamide resin whose constituent components are an aromatic dicarboxylic acid and an aliphatic diamine), the kneading temperature is not particularly limited as long as it is a temperature at which the semi-aromatic polyamide resin melts but does not decompose, but if the kneading temperature is too high, the semi-aromatic polyamide resin is prone to decomposition, so the kneading temperature is preferably at least (the melting point of the semi-aromatic polyamide resin -20°C) and not more than (the melting point of the semi-aromatic polyamide resin +40°C). Note that if the kneading temperature is too high, the crystalline polyamide resin may discolor due to heat.

[0033] When producing the resin composition of the present invention by melt-kneading using a twin-screw kneader, in order to obtain a resin composition having a temperature-decreasing crystallization temperature difference (ΔT) of 5°C or more, it is necessary to maintain the degree of kneading (Q / Ns: Q = discharge rate of kneaded resin composition (kg / hour), Ns = screw rotation speed (rpm)) at 0.10 or less. Because excessive kneading of a resin composition can easily cause decomposition and discoloration due to heat, melt-kneading has traditionally been performed at a degree of kneading of approximately 0.15. The present inventors have discovered that conventional melt-kneading at a degree of kneading of approximately 0.15 cannot produce a resin composition having a temperature-decreasing crystallization temperature difference (ΔT) of 5°C or more, and therefore cannot suppress the crystallization rate of the resin composition. However, by adjusting the degree of kneading to 0.10 or less, which was previously unanticipated, it is surprisingly possible to obtain a resin composition having a temperature-decreasing crystallization temperature difference (ΔT) of 5°C or more, thereby suppressing the crystallization rate of the resin composition. The degree of kneading must be appropriately adjusted depending on the shape of the screw used, within the range of 0.10 or less. The screw can be any screw commonly used for melt-kneading resins without any particular limitations. The degree of kneading is preferably 0.07 or less, more preferably 0.05 or less, from the viewpoint of further suppressing the crystallization rate of the resin composition. The method for extracting the obtained resin composition is not particularly limited, but in consideration of subsequent molding, it is preferable to melt-knead the resin composition in a twin-screw kneader, draw it out in the form of a strand, cool it to solidify it, and then pelletize it to obtain resin composition pellets.

[0034] [Resin molding] The resin composition of the present invention is preferably used as a raw material for a resin molded article. The resin molded article of the present invention can be produced using the resin composition of the present invention by a conventional molding method. Since the resin molded article of the present invention is molded using the resin composition of the present invention, it has a low mold shrinkage rate and excellent chemical resistance. Examples of molding methods include injection molding, extrusion molding, blow molding, and sinter molding. Among these, injection molding is preferred because it can sufficiently improve mechanical properties and moldability. The injection molding machine is not particularly limited, but examples include a screw in-line injection molding machine and a plunger injection molding machine. The resin composition heated and melted in the cylinder of the injection molding machine is measured for each shot, injected into a mold in a molten state, cooled and solidified into a predetermined shape, and then removed from the mold as a molded article. The resin temperature during injection molding is preferably equal to or higher than the Tm of the resin composition but lower than (Tm + 100°C). When molding the resin composition of the present invention, it is preferable to use resin composition pellets that have been thoroughly dried. If the moisture content is high, the resin may foam in the cylinder of the injection molding machine, making it difficult to obtain an optimal resin molded product. Furthermore, the amorphous polyarylate resin may hydrolyze to lower its molecular weight, resulting in reduced mechanical properties. The moisture content of the resin composition pellets used in injection molding is preferably less than 0.05% by mass, more preferably less than 0.03% by mass, based on 100% by mass of the resin composition. The mold temperature during injection molding must be maintained below the glass transition temperature (Tg) of the amorphous polyarylate resin, preferably below (Tg - 30°C), more preferably below (Tg - 50°C). If the mold temperature exceeds the Tg of the amorphous polyarylate resin, the resin composition may not be sufficiently solidified when the resin molded product is released from the mold, resulting in deformation. The mold temperature refers to the actual temperature of the mold parting surface, and is adjusted using a mold temperature controller so that this temperature is within the above temperature range. If necessary, a refrigerant may be circulated within the mold.

[0035] [Uses of resin composition and resin molded article] The resin composition and resin molded article of the present invention can be used in a wide range of applications, such as automobile parts, electric and electronic parts, miscellaneous goods, and civil engineering and construction supplies.

[0036] Examples of automotive parts include engine peripheral parts such as engine covers, air intake manifolds, throttle bodies, air intake pipes, radiator tanks, radiator supports, radiator hoses, radiator grills, timing belt covers, water pump receptacles, water pump outlets, cooling fans, fan shrouds, and engine mounts; mechanical parts such as propeller shafts, stabilizer bar linkage rods, accelerator pedals, pedal modules, seal rings, bearing retainers, and gears; oil pans, oil filter housings, oil filter caps, oil level gauges, fuel tanks, fuel tubes, fuel cut-off valves, canisters, and fuel delivery systems. These include fuel and piping parts such as barry pipes, fuel filler necks, fuel sender modules, and fuel piping fittings; electrical parts such as wire harnesses, relay blocks, sensor housings, encapsulations, ignition coils, distributors, thermostat housings, quick connectors, lamp reflectors, lamp housings, lamp extensions, and lamp sockets; and various interior and exterior parts such as rear spoilers, wheel covers, hubcaps, cowl vent grilles, air outlet louvers, air scoops, hood bulges, fenders, tailgates, shift lever housings, window regulators, door locks, door handles, and outside door mirror stays.

[0037] Examples of the electric and electronic components include connectors, LED reflectors, switches, sensors, sockets, capacitors, jacks, fuse holders, relays, coil bobbins, resistors, ICs, LEDs, and housings.

[0038] Examples of miscellaneous items include watch cases, fasteners, and screws. [Example]

[0039] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Measurements of physical properties and the like were carried out by the following methods.

[0040] 1.Measurement method (1) The amount of heat absorbed (ΔH) due to the crystallization of the crystalline polyamide resin upon cooling, the crystallization temperature of the crystalline polyamide resin upon cooling, the crystallization temperature of the resin composition upon cooling, the melting point of the crystalline polyamide resin, and the crystallization temperature difference upon cooling (ΔT) Using a differential scanning calorimeter (Hitachi High-Tech Science Corporation, DSC7000 series), a crystalline polyamide resin was heated to 360 ° C at a heating rate of 30 ° C / min to melt, then held at 360 ° C for 5 minutes, and then cooled to 30 ° C at a cooling rate of 20 ° C / min. The temperature at the top of the exothermic peak was taken as the temperature-cooling crystallization temperature ( ° C) of the crystalline polyamide resin, and the peak area of ​​the exothermic peak was taken as the endothermic amount (ΔH) (mJ / mg) resulting from the temperature-cooling crystallization of the crystalline polyamide resin. After cooling to 30 ° C, the sample was held at 30 ° C for another 5 minutes, and then heated again at a heating rate of 30 ° C / min. The temperature at the top of the endothermic peak was taken as the melting point ( ° C). Using the differential scanning calorimeter, the prepared resin composition was heated to 360°C at a heating rate of 30°C / min to melt it, then held at 360°C for 5 minutes, and then cooled to 30°C at a cooling rate of 20°C / min. The top temperature of the exothermic peak when the temperature was lowered was taken as the cooling crystallization temperature (°C) of the prepared resin composition. Then, the temperature-lowering crystallization temperature difference (ΔT) (° C.) was calculated using the following formula (1). Temperature-reducing crystallization temperature difference = (temperature-reducing crystallization temperature of crystalline polyamide resin) - (temperature-reducing crystallization temperature of resin composition) (1)

[0041] (2) Inherent viscosity of amorphous polyarylate resin A sample solution with a concentration of 1 g / dL was prepared by dissolving an amorphous polyarylate resin in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 60 / 40 (mass ratio). Then, using an Ubbelohde viscometer, the falling speed of the prepared sample solution and the mixed solvent was measured at a temperature of 25°C. The inherent viscosity of the amorphous polyarylate resin was calculated using the following formula. Inherent viscosity = ln [(drop time of sample solution / drop time of mixed solvent) / resin concentration of sample solution (g / dL)]

[0042] (3) Carboxyl value of amorphous polyarylate resin 0.30 g of amorphous polyarylate resin was dissolved in 20 mL of methylene chloride, and phenol red was added as an indicator to obtain a sample solution. While stirring the obtained sample solution, 0.1 N KOH (ethanol-benzyl alcohol) solution was added dropwise to the sample solution, and the carboxyl value (equivalents / ton) was determined by neutralization titration.

[0043] (4) Presence or absence of voids in the resin molded body The resin composition pellets produced in the examples and comparative examples were injection-molded using an injection molding machine (Toshiba Machine Co., Ltd., EC100) and a mold to prepare test pieces (resin molded bodies) measuring 127 mm in length, 12.7 mm in width, and 3.2 mm in thickness. The test pieces were cut in the thickness direction at a position 63.5 mm in length, and the cross sections were visually inspected for the presence of voids of 800 μm or more. In Examples 1 to 8, 10 to 13, and Comparative Examples 1 to 6, the cylinder temperature was 340°C and the mold temperature was 130°C. In Example 9, the cylinder temperature was 270°C and the mold temperature was 100°C.

[0044] (5) Mold shrinkage rate The resin composition pellets produced in the examples and comparative examples were injection molded using an injection molding machine (Toshiba Machine Co., Ltd., EC100) and a mold (width 60 mm, length 60 mm, thickness 3 mm) to prepare test specimens (resin molded articles). In Examples 1 to 8, 10 to 13 and Comparative Examples 1 to 6, the cylinder temperature was 340°C and the mold temperature was 130°C. In Example 9, the cylinder temperature was 270°C and the mold temperature was 100°C. The width (mm) of the obtained test specimens was measured using a digital caliper (Mitutoyo Corporation, CD-20AX), and the mold shrinkage (%) was calculated using the following formula. The mold shrinkage is preferably 1.0% or less, and more preferably 0.8% or less. Mold shrinkage rate = [(mold width - test piece width) / mold width] x 100

[0045] (6) Chemical resistance The resin composition pellets produced in the examples and comparative examples were injection-molded using an injection molding machine (Toshiba Machine Co., Ltd., EC100) and a mold to prepare test pieces (resin molded articles) measuring 127 mm in length, 12.7 mm in width, and 3.2 mm in thickness. In Examples 1 to 8, 10 to 13, and Comparative Examples 1 to 6, the cylinder temperature was 340°C and the mold temperature was 130°C. In Example 9, the cylinder temperature was 270°C and the mold temperature was 100°C. As shown in FIG. 1(A), test piece 1 (thickness: h) was fixed in a bent state between cylindrical support 2 and cylindrical support 3, and the distance L between the two cylindrical support parts 3 was measured. The height y from the center of the test piece in contact with cylindrical support 2 to the center of the test piece in contact with cylindrical support part 3 was also measured. The strain rate (%) was calculated using the following formula, and the strain rate was adjusted to 1%. Distortion rate (ε) = 6hy / L 2 1(B), absorbent cotton 4 (20 mm × 20 mm) sufficiently soaked in cutting oil (Yushiro Chemical Co., Ltd., Yushiroken) was placed on the test piece, and the test piece was then placed in a constant-temperature hot air oven at 80°C for 3 hours for heat treatment. After the heat treatment, the cylindrical supports 2 and 3 were removed, and the surface of the test piece on which the absorbent cotton 4 was placed was visually observed and evaluated according to the following criteria. [Evaluation criteria] ◎: No change 〇: 3 or less cracks ×: 4 or more cracks or cracks

[0046] 2.Raw materials The raw materials used in the examples and comparative examples are shown below. (1) Polyamide resin (A-1) Polyamide 10T (Unitika, XP500): Crystallization temperature: 289°C, melting point: 315°C (A-2) Polyamide 9T (Kuraray Co., Ltd., N1000A): Crystallization temperature: 270°C, Melting point: 300°C (A-3) Polyamide 46 (manufactured by DSM, TW341): Crystallization temperature on cooling: 252°C, Melting point: 295°C (A-4) Polyamide 6 (Unitika Ltd., A1030BRL): Crystallization temperature on cooling: 163°C, Melting point: 225°C (A-5) Amorphous polyamide (EMS, G21)

[0047] (2) Polyarylate resin (B-1) Amorphous polyarylate (Unitika Ltd., U Powder C type): inherent viscosity 0.55 dL / g, carboxyl value: 46 equivalents / ton (B-2) Amorphous polyarylate (Unitika Ltd., U Powder R type): inherent viscosity 0.52 dL / g, carboxyl value: 8 equivalents / ton

[0048] (3) Glass fiber (C-1) Chopped strand (manufactured by Nippon Electric Glass Co., Ltd., ECS03T-262H)

[0049] (4) Antioxidants (D-1) Phosphorus-based antioxidant (ADEKA Corporation, ADK STAB PEP-36)

[0050] (5) Compatibilizer (E-1) Ethylene-glycidyl methacrylate copolymer (Sumitomo Chemical Co., Ltd., BF-E)

[0051] Example 1 Ninety parts by weight of crystalline polyamide resin (A-1) and 10 parts by weight of amorphous polyarylate resin (B-1) were weighed using a loss-in-weight continuous metering feeder (KUBOTA, Model CE-W-1) and fed into the main feed port of a co-rotating twin-screw extruder (Toshiba Machine, Model TEM37BS) with a screw diameter of 37 mm and an L / D ratio of 40°C, where they were melt-kneaded. After being drawn through the die in the form of a strand, the strand was passed through a water bath to cool and solidify, and then cut into pellets using a pelletizer to obtain resin composition pellets. The barrel temperature of the extruder was set to 320°C to 340°C, the screw rotation speed was 700 rpm, and the output rate was 35 kg / h. The degree of kneading (output rate / screw rotation speed) was 0.05.

[0052] Examples 2 to 8, 10 to 13, Comparative Examples 1 to 6 Resin composition pellets were obtained in the same manner as in Example 1, except that the type and blending ratio of the resin, the presence or absence of glass fiber, the presence or absence of an antioxidant, the presence or absence of a compatibilizer, and the screw rotation speed were changed.

[0053] Example 9 Resin composition pellets were obtained in the same manner as in Example 1, except that the type of resin was changed and the barrel temperature of the extruder was set to 270°C.

[0054] The composition and properties of the obtained resin composition, as well as the physical properties of the resin molded product, are shown in Tables 1 and 2.

[0055] [Table 1]

[0056] [Table 2]

[0057] As shown in Table 1, the resin compositions (Examples 1 to 13) containing a crystalline polyamide resin and an amorphous polyarylate resin and having a temperature-decreasing crystallization temperature difference (ΔT) of 5°C or more had a suppressed crystallization rate, and therefore were able to effectively suppress the generation of voids in the resin molded article without raising the mold temperature. Furthermore, the obtained resin molded article had excellent chemical resistance.

[0058] On the other hand, as shown in Table 2, in the resin composition containing an amorphous polyamide resin and an amorphous polyarylate resin (Comparative Example 1), when only an amorphous polyarylate resin was used (Comparative Example 3), and when the content of the amorphous polyarylate resin was high (Comparative Example 4), voids did not occur in the resin molded body even without heating the mold to a high temperature because an amorphous resin was used, but the resulting resin molded body had poor chemical resistance. When only a crystalline polyamide resin was used (Comparative Example 2), voids occurred in the resin molded body because the crystallization rate could not be suppressed. In the resin compositions (Comparative Examples 5 and 6) in which the temperature-lowering crystallization temperature difference (ΔT) was 0°C due to a high degree of kneading, voids occurred in the resin molded body because the crystallization rate could not be suppressed. [Explanation of symbols]

[0059] 1 Test piece (resin molded body) 2 Cylindrical support part (inside) 3 Cylindrical support part (outside) 4. Absorbent cotton soaked in cutting oil

Claims

1. A resin composition containing a crystalline polyamide resin and an amorphous polyarylate resin, wherein the temperature-lowering crystallization temperature difference (ΔT) calculated by the following formula (1) is 5°C or more. Temperature-reducing crystallization temperature difference = (temperature-reducing crystallization temperature of crystalline polyamide resin) - (temperature-reducing crystallization temperature of resin composition) (1)

2. The resin composition according to claim 1, wherein the crystalline polyamide resin has an endothermic heat (ΔH) resulting from crystallization upon cooling of 10 mJ / mg or more.

3. The resin composition according to claim 1, wherein the mass ratio of the crystalline polyamide resin to the amorphous polyarylate resin (crystalline polyamide resin / amorphous polyarylate resin) is 98 / 2 to 35 / 65.

4. The resin composition according to claim 1 , wherein the crystalline polyamide resin is an aromatic polyamide resin.

5. The resin composition according to claim 1 , wherein the amorphous polyarylate resin has a carboxyl value of 12 equivalents / ton or more.

6. A resin molded article obtained from the resin composition according to any one of claims 1 to 5.

7. The method for producing a resin composition according to any one of claims 1 to 5, comprising a step of kneading at least the crystalline polyamide resin and the amorphous polyarylate resin so that the temperature-lowering crystallization temperature difference (ΔT) calculated by the formula (1) is 5 ° C. or more.

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