Manufacturing method for resin molded products

Abstract

To provide a method for manufacturing a resin molded product, which solves molding defects such as increased cycle time, mold release failure, deformation and burrs that occur when PET such as recycled PET resin is used for injection molding.SOLUTION: A method for manufacturing a resin molded product includes a step of obtaining a resin molded product by injection molding a polyphenylene ether-based resin composition. The polyphenylene ether-based resin composition contains polyphenylene ether, polyethylene terephthalate, and an inorganic filler. A crystallization heat value of the polyphenylene ether-based resin composition at a first temperature lowering time measured by a differential scanning calorimetry (DSC) is 23 J / g or more and 45 J / g or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a resin molded product.

Background Art

[0002] Conventionally, polyethylene terephthalate (hereinafter sometimes referred to as PET) has been widely used as beverage bottles and food containers because it is inexpensive, has excellent transparency, has design properties, and has high gas barrier properties. In recent years, due to its high versatility and extensive use, the disposal of containers has not caught up worldwide. There is a global social concern about how to effectively utilize waste PET bottles as resources, such as the problem of some becoming floating plastics that pollute the ocean. In order to improve various physical properties such as physical properties, moldability, and flame retardancy when recycling waste PET bottles, for example, a method of alloying with polyphenylene ether (hereinafter sometimes referred to as PPE) (Patent Document 1), a method of adding another polyester resin such as a lactone polymer (Patent Document 2), and a method of containing a phosphorus element (Patent Document 3) are known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] One of the technical challenges in considering the effective utilization of discarded PET bottles is the difficulty in repurposing them as resin for injection molding. The PET used in bottle containers is a high-molecular-weight type intended for blow molding, and when used in injection molding, it exhibits poor release properties during molding, requiring longer cooling times. Furthermore, some molded parts may stick together when ejected after mold opening. In addition, shrinkage due to cooling after molding and dimensional changes during reheating can be significant. As a result, problems such as decreased productivity due to longer cycle times and an increase in defective products due to deformation of the molded parts occur, and these phenomena are particularly pronounced in flat molded bodies with a large surface area relative to their thickness. Thus, discarded PET bottles are unsuitable materials for injection molding. Furthermore, even when using the methods disclosed in the aforementioned Patent Documents 1 to 3, the methods were still insufficient to solve the problems of release properties and molding defects when using PET such as recycled PET resin as injection molded products.

[0005] This invention has been made in view of the above circumstances, and its objective is to provide a method for manufacturing resin molded products that solves problems such as increased cycle time, poor release, deformation, and burrs that occur when PET, such as recycled PET resin, is used for injection molding. [Means for solving the problem]

[0006] As a result of diligent research to solve the above problems, the present inventors have found that it is possible to provide a method for manufacturing resin molded products that does not result in increased cycle time, poor release, warping, or burrs, even when using high molecular weight PET such as recycled PET resin to manufacture molded products with a large surface area relative to their thickness by injection molding, and have completed the present invention.

[0007] In other words, the present invention is as follows: [1] A method for producing a resin molded product, comprising the step of injection molding a polyphenylene ether-based resin composition to obtain a resin molded product, The polyphenylene ether-based resin composition comprises polyphenylene ether, polyethylene terephthalate, and an inorganic filler. A method for manufacturing a resin molded product, characterized in that the amount of crystallization heat during the first cooling of the first cycle, measured by differential scanning thermal analysis (DSC) of the polyphenylene ether resin composition, is 23 J / g or more and 45 J / g or less, after raising the temperature from 23°C to 350°C at a heating rate of 20°C / min, holding at 350°C for 3 minutes, and then cooling down to 80°C at 20°C / min. [2] The ratio of the surface area A to the thickness T of the aforementioned resin molded product (A / T) is 125 cm². 2 A method for manufacturing a resin molded product of [1] that is 1 cm or larger. [3] A method for manufacturing a resin molded product according to [1] or [2], wherein the amount of warpage of the resin molded product is 2.3 mm or less. [4] A method for producing a resin molded article according to any of [1] to [3], wherein the total content of polyphenylene ether, polyethylene terephthalate, and inorganic filler is 99 to 100% by mass, based on 100% by mass of the polyphenylene ether-based resin composition. [5] A method for producing a resin molded article according to any of [1] to [4], wherein the weight-average molecular weight of the polyethylene terephthalate is 80,000 or more. [6] A method for producing a resin molded article according to any of [1] to [5], wherein the weight-average molecular weight of the polyphenylene ether resin composition is 50,000 or more. [7] A method for producing a resin molded article according to any one of [1] to [6], wherein the polyphenylene ether-based resin composition has a mass ratio of 30 to 90 parts by mass of polyethylene terephthalate relative to 100 parts by mass of the total mass of the polyphenylene ether and the polyethylene terephthalate. [8] The aforementioned polyethylene terephthalate is used as part of a resin molded product manufacturing method, which involves recovering and crushing a finished resin molded product. (1) to (7) [9] A method for manufacturing a resin molded product according to any one of [1] to [8], which contains 20 to 60% by mass of the inorganic filler with respect to 100% by mass of the polyphenylene ether-based resin composition.

[10] A method for manufacturing a resin molded product according to any one of [1] to [9], wherein the transmittance of the polyphenylene ether-based resin composition at 940 nm and 2 mmt is 30% or more and 100% or less.

[11] A method for manufacturing a resin molded product according to any one of [1] to

[10] , wherein the coefficient of friction of the surface of the resin molded product is 0.2 or less.

[12] A method for manufacturing a resin molded product according to any one of [1] to

[11] , wherein the heat deflection temperature (ISO75) of the resin molded product is 140°C or higher. 13 A polyphenylene ether-based resin composition containing polyphenylene ether, polyethylene terephthalate, and an inorganic filler, The crystallization heat generation amount during the first cooling in the 1st cycle, which is measured by differential scanning calorimetry (DSC), raised from 23°C to 350°C at a heating rate of 20°C / min, held at 350°C for 3 minutes, and then cooled to 80°C at a rate of 20°C / min, is 23 J / g or more and 45 J / g or less. thing.

Advantages of the Invention

[0008] According to the present invention, even when a molded product with a large surface area relative to its thickness is manufactured by injection molding using PET for blow molding such as recycled PET resin, a method for manufacturing a resin molded product can be provided that has good mold release properties, little deformation due to warpage after molding, and does not generate burrs, which is one of the molding defects.

Embodiments for Carrying Out the Invention

[0009] ​​Hereinafter, embodiments for implementing the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The following present embodiment is an exemplification for explaining the present invention, and the present invention is not limited to the following embodiments. Further, the present invention can be implemented with appropriate modifications within the scope of its gist.

[0010] <Method for manufacturing resin molded product> The method for manufacturing a resin molded product of the present embodiment is a method for manufacturing a resin molded product including a step of obtaining a resin molded product by injection molding a polyphenylene ether-based resin composition, wherein the polyphenylene ether-based resin composition contains polyphenylene ether, polyethylene terephthalate, and an inorganic filler, and the heat of crystallization during the first temperature drop measured by differential scanning calorimetry (DSC) of the polyphenylene ether-based resin composition is 23 J / g or more and 45 J / g or less. According to the above manufacturing method, even when high molecular weight PET such as recycled PET resin is used for injection molding, it tends to be possible to prevent an increase in cycle time, poor mold release, molding defects such as deformation and burrs.

[0011] Hereinafter, the polyphenylene ether-based resin composition and the like used in the manufacturing method of the present embodiment will be described in detail.

[0012] <Polyphenylene ether-based resin composition> The polyphenylene ether-based resin composition contains polyphenylene ether, polyethylene terephthalate, and an inorganic filler, and the heat of crystallization during the first temperature drop measured by differential scanning calorimetry (DSC) of the polyphenylene ether-based resin composition is 23 J / g or more and 45 J / g or less. The heat of crystallization during the first temperature drop is preferably 25 J / g or more and 45 J / g or less. The polyphenylene ether-based resin composition may further contain an emulsifying dispersant, a compatibilizer, a flame retardant, an additive, and the like. The polyphenylene ether-based resin composition may be a composition consisting only of the polyphenylene ether, the polyethylene terephthalate, the inorganic filler, and the emulsifying dispersant.

[0013] The PET contained in the above-mentioned polyphenylene ether resin composition, due to its chemical structure, requires a much slower crystallization time compared to other crystalline polyester resins. Furthermore, PET with a higher molecular weight tends to require an even slower crystallization time. However, by setting the amount of crystallization heat generated during the initial cooling, as measured by DSC, within the above range, molding defects due to slow crystallization can be effectively prevented.

[0014] The weight-average molecular weight of the above polyphenylene ether resin composition is preferably 40,000 or more, more preferably 50,000 or more, and even more preferably 60,000 or more. The upper limit of the weight-average molecular weight is not particularly limited, but it can be 150,000 or less, and preferably 120,000 or less. Having a weight-average molecular weight of 40,000 or more allows for adjustment of fluidity within a suitable range, which tends to effectively prevent burrs, a type of molding defect. The weight-average molecular weight of the polyphenylene ether resin composition can be measured by GPC, specifically by the method described in the examples.

[0015] The amount of heat generated during crystallization at the initial cooling stage of the above polyphenylene ether resin composition, as measured by DSC (Differential Scanning Thermal Analysis), is 23 J / g or more and 45 J / g or less, preferably 25 J / g or more and 42 J / g or less, more preferably 27 J / g or more and 39 J / g or less, and even more preferably 30 J / g or more and 37 J / g or less. Having the amount of heat generated during crystallization within this range means that the degree of crystallization of the polyphenylene ether resin composition is within an appropriate range, resulting in a moderately fast solidification rate. Therefore, adhesion to the mold during demolding and mold opening can be prevented, and there is no difference between parts that are pushed out and parts that are not by the ejector pins, thus tending to prevent warping. Since the amount of heat generated during crystallization varies depending on the type and mass ratio of the resin and the mass ratio of the inorganic filler, it is particularly desirable to adjust the mass ratio of PPE and PET, the mass ratio of the inorganic filler, and the weight-average molecular weight of PET in the resin composition to an appropriate range. Specifically, increasing the mass proportion of inorganic fillers (for example, setting the mass proportion of inorganic fillers to a suitable range as described later) tends to reduce the heat of crystallization. Also, adding a small amount of PPE to PET (for example, setting the mass ratio of PET to the total mass of PPE and PET to a suitable range as described later) tends to increase the heat of crystallization, but if the ratio of PPE becomes too high (for example, if it falls below the suitable range for the mass ratio of PET to the total mass of PPE and PET as described later), the heat of crystallization tends to decrease. Furthermore, the higher the weight-average molecular weight of PET, the lower the heat of crystallization tends to be.

[0016] The total mass ratio of the polyphenylene ether, polyethylene terephthalate, and inorganic filler to 100% by mass of the polyphenylene ether resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 80% by mass or more. The total mass ratio may also be 100% by mass. Furthermore, in embodiments including an emulsifying dispersant and / or a phase solvent, the total mass ratio of the polyphenylene ether, polyethylene terephthalate, inorganic filler, emulsifying dispersant, and phase solvent to 100% by mass of the polyphenylene ether resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 80% by mass or more. The total mass ratio may also be 100% by mass. Satisfying the above range tends to allow the effects of this embodiment to be expressed more favorably.

[0017] (Polyphenylene ether) The structure of the polyphenylene ether described above is not particularly limited, but it is preferably a homopolymer and / or copolymer polyphenylene ether consisting of repeating units represented by the following bonding unit formula (1), and having an intrinsic viscosity of 0.16 to 0.36 dL / g, more preferably 0.20 to 0.34 dL / g, as measured in chloroform at 30°C. [ka] (Here, R1, R2, R3, and R4 are each selected from the group consisting of hydrogen, halogen, primary or secondary lower alkyl group having 1 to 7 carbon atoms, phenyl group, haloalkyl group, aminoalkyl group, hydrocarbon oxy group, or halohydrocarbon oxy group in which at least two carbon atoms separate the halogen atom and the oxygen atom, and may be the same or different from each other. Also, n is an integer of 1 or more.)

[0018] By setting the intrinsic viscosity of the polyphenylene ether resin to 0.16 dL / g or higher, a good balance between mechanical properties, fluidity, and mold release properties can be achieved. By setting it to 0.36 dL / g or lower, fluidity (e.g., SFD properties at 0.5 mm) and flame retardancy can be enhanced, especially in the high-sheave range.

[0019] Specific examples of the above PPE include, for example, poly(2,6-dimethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2-methyl-6-phenyl-1,4-phenylene ether), poly(2,6-dichloro-1,4-phenylene ether), and polyphenylene ether copolymers such as copolymers of 2,6-dimethylphenol with other phenols (e.g., 2,3,6-trimethylphenol and 2-methyl-6-butylphenol). Among these, poly(2,6-dimethyl-1,4-phenylene ether) and copolymers of 2,6-dimethylphenol and 2,3,6-trimethylphenol are preferred, and poly(2,6-dimethyl-1,4-phenylene ether) is even more preferred.

[0020] The method for producing the above-mentioned PPE is not particularly limited. For example, it can be easily produced by using a complex of cuprous salt and amine by Hay as described in U.S. Patent No. 3,306,874 as a catalyst and oxidative polymerization of, for example, 2,6-xylenol. It can also be easily produced by adjusting the intrinsic viscosity using methods described in U.S. Patent No. 3,306,875, U.S. Patent No. 3,257,357, U.S. Patent No. 3,257,358, Japanese Patent Publication No. 52-17880, Japanese Unexamined Patent Publication No. 50-51197, and Japanese Unexamined Patent Publication No. 63-152628, etc.

[0021] As mentioned above, polyphenylene ether is preferably 100% by weight of PPE component, but when used as a polymer alloy, a polymer alloy with a PPE content of 1 to 99% by weight can also be used. When polyphenylene ether is used as the polymer alloy described above, polystyrene and the like can be used as resins together with the polyphenylene ether. Examples of polystyrene include homopolymers of styrene compounds, copolymers of two or more styrene compounds, and high-impact polystyrene such as rubber-modified styrene in which a rubbery polymer is dispersed in particulate form in a matrix of polymers of styrene compounds. Examples of styrene compounds that yield these polymers include styrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, α-methylstyrene, ethylstyrene, α-methyl-p-methylstyrene, 2,4-dimethylstyrene, monochlorostyrene, and p-tert-butylstyrene. Among these, polystyrene obtained by polymerization using styrene alone is preferred. Furthermore, polystyrene resins having a stereoregular structure, such as atactic polystyrene and syndiotactic polystyrene, can be effectively used as polyphenylene ether resins.

[0022] The mass ratio of the polyphenylene ether to 100% by mass of the above polyphenylene ether-based resin composition is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and even more preferably 13 to 30% by mass, from the viewpoint of further reducing the occurrence of molding defects such as poor release, warping, and burrs during injection molding.

[0023] (Polyethylene terephthalate) The above-mentioned PET preferably has a weight-average molecular weight of 80,000 or more, more preferably 90,000 or more, and even more preferably 100,000 or more. A weight-average molecular weight of 80,000 or more tends to suppress the increase in brittleness and increase impact strength. In addition, low molecular weight components have the effect of increasing fluidity, which may make it easier to produce burrs, one of the molding defects. There is no particular upper limit to the weight-average molecular weight, but it may be 150,000 or less, and preferably 120,000 or less. The weight-average molecular weight of PET can be measured by GPC, specifically by the method described in the examples. When measuring the weight-average molecular weight of PET from a polyphenylene ether resin composition, PET and PPE can be separated by known methods, such as Soxhlet extraction or other solvent reprecipitation methods, and the weight-average molecular weight of PET can be measured after extraction.

[0024] PET is widely used in bottles and films. Given the growing social demand for environmental considerations, it is desirable to use waste materials that would otherwise be discarded, such as containers used in general households or commercial settings, or waste materials cut during processing in their industrial production. Crushed PET chips are preferred, and more preferably, processed into granular pellets. For the crushed PET raw material, materials with a consistent shape are preferable due to processing and handling during mixing.

[0025] In the above polyphenylene ether resin composition, the mass ratio of PET and PPE to 100 parts by mass of the total mass of PET and PPE is preferably in the range of 30 to 90 parts by mass of PET and 10 to 70 parts by mass of PPE. More preferably, it is in the range of 50 to 87 parts by mass of PET and 13 to 50 parts by mass of PPE, and even more preferably, it is in the range of 55 to 85 parts by mass of PET and 15 to 45 parts by mass of PPE. A mass ratio of PET and PPE within this range is preferable from the viewpoint of release properties, dimensional stability, chemical resistance, heat resistance, and mechanical properties.

[0026] -Recycling methods for polyethylene terephthalate- From a recycling perspective, it is preferable to use crushed polyethylene terephthalate collected from manufactured resin molded products as part of the raw material, or the entire amount may be crushed polyethylene terephthalate. According to the manufacturing method of this embodiment, by using a composition containing polyphenylene ether, inorganic fillers, etc., in specific proportions, it is possible to prevent problems such as release properties and molding defects during injection molding, even when using crushed polyethylene terephthalate. The above polyethylene terephthalate recycling method involves a step of collecting manufactured resin molded products, crushing them, and using the resulting polyethylene terephthalate as part of the raw materials, then kneading the resulting polyethylene terephthalate with raw materials containing polyphenylene ether and inorganic fillers to obtain a polyphenylene ether-based resin composition. A method for recycling polyethylene terephthalate, comprising the step of injection molding the above-mentioned polyphenylene ether-based resin composition to obtain a resin molded product, The above polyphenylene ether-based resin composition has a crystallization exothermic amount of 23 J / g or more and 45 J / g or less during the initial cooling, as measured by differential scanning thermal analysis (DSC).

[0027] By recycling polyethylene terephthalate using the method described above, it is possible to recycle flat molded bodies, especially those with a large surface area relative to their thickness, such as those with a surface area A to thickness T ratio (A / T) of 125 cm². 2Even when injection molding molded parts with a thickness of 1 / cm or more, it tends to effectively prevent increased cycle time, poor release, deformation, and molding defects such as burrs.

[0028] The mass ratio of polyethylene terephthalate to 100% by mass of the above polyphenylene ether resin composition is preferably 20 to 75% by mass, more preferably 30 to 65% by mass, and even more preferably 40 to 60% by mass, from the viewpoint of further reducing the occurrence of molding defects such as poor release, warping, and burrs during injection molding. Furthermore, the mass ratio of the PET to 100 parts by mass of the total mass of the PPE and the inorganic filler is preferably 50 to 150 parts by mass, more preferably 60 to 135 parts by mass, and even more preferably 70 to 120 parts by mass, from the viewpoint of further reducing the occurrence of molding defects such as poor release, warping, and burrs during injection molding.

[0029] (Inorganic filler) The above polyphenylene ether resin composition contains an inorganic filler. The inorganic filler is not particularly limited, but it is preferably one or more selected from the group consisting of fibrous inorganic fillers and flaky inorganic fillers.

[0030] The inorganic filler mentioned above may be treated with a surface treatment agent such as a silane-based coupling agent, a titanate-based coupling agent, or an aliphatic metal salt, or it may be treated with a resin such as urethane resin or epoxy resin as a binder.

[0031] The mass percentage of the inorganic filler in the above polyphenylene ether resin composition is not particularly limited, but it is preferably 20 to 60% by mass relative to 100% by mass of the polyphenylene ether resin composition. A value of 20% by mass or more tends to improve mechanical strength, while a value of 60% by mass or less tends to ensure higher surface smoothness.

[0032] The fibrous inorganic filler described above is not particularly limited as long as it is fibrous, but it is preferable that its average length is 50 to 170 μm. A length of 50 μm or more tends to improve mechanical strength, while a length of 170 μm or less tends to improve surface smoothness. It is presumed that using a short inorganic filler with an average length of 170 μm or less suppresses the protrusion of the inorganic filler onto the surface of the resin molded product, thereby preventing the boundary between the inorganic filler and the resin from appearing on the surface and thus ensuring surface smoothness. The average length of the fibrous inorganic filler is preferably 80 to 165 μm, and more preferably 120 to 160 μm. The average length of the fibrous inorganic filler can be measured by the following method.

[0033] As the fibrous inorganic filler mentioned above, at least one selected from the group consisting of glass fibers, carbon fibers, carbon nanotubes, cellulose fibers, silicon carbide fibers, ceramic fibers, aramid fibers, alumina fibers, gypsum fibers, metal fibers, calcium titanate whiskers, calcium carbonate whiskers, and wollastonite can be used. Among these, glass fibers are preferred from the viewpoint of heat resistance and adhesion to the resin.

[0034] The above-mentioned flake-shaped inorganic filler is not particularly limited as long as it is flake-shaped, but its average major diameter is preferably 1000 μm or less, more preferably 1 to 500 μm, and even more preferably 1 to 200 μm. Furthermore, its average minor diameter is preferably 1000 μm or less, more preferably 1 to 500 μm, and even more preferably 1 to 200 μm. In addition, the aspect ratio (L1 / L2) of the average major diameter L1 to the average minor diameter L2 of the flake-shaped inorganic filler is preferably 3 or less, more preferably 2 or less, and even more preferably 1.6 or less.

[0035] The flake-shaped inorganic filler is preferably one in which the average aspect ratio (L1 / T) of the average major diameter L1 to the average thickness T is greater than 5, more preferably 10 or more, and even more preferably 30 or more. The average major diameter, average minor diameter, and thickness of the flake-shaped inorganic filler can be measured by the following method. Examples of flake-like inorganic fillers include glass flakes and mica.

[0036] The average length, average major axis, average minor axis, and thickness of the inorganic filler can be measured as follows. First, the resin molded product manufactured by the method of this embodiment is placed, for example, in an electric furnace to incinerate the molded body, and the inorganic filler is collected from the residue (ash). When collecting the inorganic filler from the residue, if the resin molded product contains fillers other than the inorganic filler, the residue derived from the non-inorganic filler and the residue derived from the inorganic filler can be separated by dispersing all the residue in water or another solvent and allowing it to settle. Furthermore, the method for measuring the average length, average major diameter, average minor diameter, and thickness of the inorganic filler is not particularly limited as long as an image processing device is capable of observing the inorganic filler with a microscope and binarizing the obtained image. The measured value can be the arithmetic mean of the values ​​obtained from a sufficient number (for example, 100) randomly sampled.

[0037] The mass ratio of the inorganic filler to 100 parts by mass of the polyphenylene ether is preferably 50 to 350 parts by mass, more preferably 65 to 300 parts by mass, and even more preferably 80 to 250 parts by mass, from the viewpoint of further reducing the occurrence of molding defects such as poor release, warping, and burrs during injection molding.

[0038] (Emulsifying dispersant, phase solvent) The above polyphenylene ether resin composition preferably further contains an emulsifying dispersant and / or a phase solvent, and more preferably contains an emulsifying dispersant. Using an emulsifying dispersant is more preferable from the viewpoint of finely dispersing the islands in the sea-island structure.

[0039] Examples of the emulsifying dispersants mentioned above include (1) epoxy resins, (2) silane coupling agents, and (3) copolymers containing epoxy groups and / or oxazolyl groups. Among these, copolymers of an unsaturated monomer having epoxy groups and / or oxazolyl groups and a monomer mainly composed of styrene are more preferably used.

[0040] The above monomer, which has styrene as its main component, is acceptable if the styrene component is 100% by weight. However, if other monomers copolymerizable with styrene are present, the copolymer chain preferably contains 65% to 100% by weight of styrene monomer, more preferably 75% to 95% by weight, from the viewpoint of maintaining miscibility with polyphenylene ether. Specific examples of compounds containing epoxy groups and / or copolymers containing oxazolyl groups include copolymers of an unsaturated monomer having an epoxy group and / or oxazolyl group with a styrene monomer, and copolymers of an unsaturated monomer having an epoxy group and / or oxazolyl group with styrene / acrylonitrile = 90-75% by weight / 10-25% by weight.

[0041] Examples of epoxy group-containing unsaturated monomers include glycidyl methacrylate, glycidyl acrylate, vinyl glycidyl ether, glycidyl ether of hydroxyalkyl (meth)acrylate, glycidyl ether of polyalkylene glycol (meth)acrylate, and glycidyl itaconate, with glycidyl methacrylate being the preferred choice. Furthermore, 2-isopropenyl-2-oxazoline is industrially available and preferably used as the oxazolyl group-containing unsaturated monomer mentioned above.

[0042] Other unsaturated monomers copolymerized with these unsaturated monomers having epoxy and / or oxazolyl groups include vinyl aromatic compounds such as styrene, which are essential components, as well as vinyl cyanide monomers such as acrylonitrile, vinyl acetate, (meth)acrylic acid esters, etc., as copolymerization components. The copolymer containing the epoxy group and / or oxazolyl group preferably contains at least 65% by mass of styrene monomer in the component excluding the unsaturated monomer having epoxy and / or oxazolyl groups. Furthermore, it is preferable that the unsaturated monomer having epoxy and / or oxazolyl groups is contained in this copolymer at 0.3 to 20% by mass, preferably 1 to 15% by mass, and more preferably 3 to 10% by mass.

[0043] The amount of unsaturated monomers having epoxy groups and / or oxazolyl groups in the copolymer of the above emulsifying dispersant component is preferably 0.3% by mass or more, and if it is 20% by mass or less, the miscibility between PET and PPE is good, and this can greatly suppress the generation of burrs in resin molded products molded using the resulting polyphenylene ether resin composition, as well as providing an excellent balance between toughness (impact strength) and rigidity.

[0044] Examples of copolymers of emulsifying and dispersing agent components obtained by copolymerizing copolymerizable unsaturated monomers include, for example, styrene-glycidyl methacrylate copolymer, styrene-glycidyl methacrylate-methyl methacrylate copolymer, styrene-glycidyl methacrylate-acrylonitrile copolymer, styrene-vinyl oxazoline copolymer, and styrene-vinyl oxazoline-acrylonitrile copolymer.

[0045] The mass ratio of the emulsifying dispersant is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of the total of the PET and PPE. If the amount is 1 part by mass or more, the effect of improving the miscibility between PET and PPE tends to be greater, and if it is 20 parts by mass or less, the generation of burrs in the resin molded product formed using the obtained polyphenylene ether resin composition can be greatly suppressed, and the balance between toughness (impact strength) and rigidity tends to be excellent.

[0046] Examples of the above-mentioned phase solvents include hydrogenated styrene-based thermoplastic elastomers, and known ones can be used.

[0047] (Flame retardant) The above polyphenylene ether resin composition may further contain a flame retardant. To improve flame retardancy, a flame retardant commonly added to thermoplastic resins can be used, but it is preferable to add a halogen-free organophosphorus flame retardant. The organophosphorus flame retardant may be used alone or in combination of two or more types.

[0048] Examples of organophosphorus-based flame retardants include phosphate ester compounds and phosphazene compounds. Phosphate ester compounds are added to improve flame retardancy, and any organophosphorus ester commonly used as a flame retardant can be used.

[0049] Specific examples of phosphate ester compounds include, but are not limited to, triphenyl phosphate, trisnonylphenyl phosphate, resorcinol bis(diphenyl phosphate), resorcinol bis[di(2,6-dimethylphenyl) phosphate], 2,2-bis{4-[bis(phenoxy)phosphoryloxy]phenyl}propane, and 2,2-bis{4-[bis(methylphenoxy)phosphoryloxy]phenyl}propane. In addition to the above, phosphorus-based flame retardants include, for example, phosphate ester flame retardants such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, tricresyl phosphate, cresylphenyl phosphate, octyldiphenyl phosphate, and diisopropylphenyl phosphate, as well as diphenyl-4-hydroxy-2,3,5,6-tetrabromobenzyl phosphate, dimethyl-4-hydroxy-3,5-dibromobenzyl phosphate, and diphenyl-4-hydroxy-3,5-dibromo Examples include benzyl phosphate, tris(chloroethyl) phosphate, tris(dichloropropyl) phosphate, tris(chloropropyl) phosphate, bis(2,3-dibromopropyl)-2,3-dichloropropyl phosphate, tris(2,3-dibromopropyl) phosphate, and monophosphate ester compounds such as bis(chloropropyl) monooctyl phosphate hydroquinonyldiphenyl phosphate, phenylnonylphenyl hydroquinonyl phosphate, and phenyldinonylphenyl phosphate, as well as aromatic condensed phosphate ester compounds. Among these, aromatic condensed phosphate ester compounds are preferred because they generate less gas during processing and have excellent thermal stability.

[0050] Preferred flame retardants are phosphate ester compounds (condensed phosphate esters) represented by the following general formula (I) or general formula (II). Particularly preferred are phosphate ester compounds (condensed phosphate esters) represented by the following general formula (I). [ka] [ka] (In general formulas (I) and (II), Q1, Q2, Q3, and Q4 are substituents, each independently representing an alkyl group having 1 to 6 carbon atoms; R11 and R12 each represent a methyl group; R13 and R14 each independently represent a hydrogen atom or a methyl group; n is an integer of 1 or more; n1 and n2 each independently represent an integer from 0 to 2; and m1, m2, m3, and m4 each independently represent an integer from 0 to 3.)

[0051] In the condensed phosphate esters represented by the above general formulas (I) and (II), in each molecule, n is an integer of 1 or more, preferably an integer from 1 to 3.

[0052] In the condensed phosphate esters represented by the above general formulas (I) and (II), preferred condensed phosphate esters are those in formula (I) where m1, m2, m3, m4, n1, and n2 are zero and R13 and R14 are methyl groups, or those in formula (I) where Q1, Q2, Q3, Q4, R13, and R14 are methyl groups, n1, and n2 are zero and m1, m2, m3, and m4 are integers from 1 to 3, and which contain 50% by mass or more of a phosphate ester in which the range of n is an integer from 1 to 3, particularly n is 1.

[0053] These aromatic condensed phosphate ester compounds are generally commercially available, and examples include CR741, CR733S, and PX200 from Daihachi Chemical Industry Co., Ltd., and FP600, FP700, and FP800 from ADEKA Corporation.

[0054] Of these aromatic condensed phosphate ester compounds, those with an acid value of 0.1 or less (a value obtained in accordance with JIS K2501) are particularly preferred from the viewpoint of thermal stability.

[0055] Furthermore, as the phosphazene compound, phenoxyphosphazene and its crosslinked derivatives are preferred, and particularly preferred are phenoxyphosphazene compounds having an acid value of 0.1 or less (a value obtained in accordance with JIS K2501) from the viewpoint of thermal stability.

[0056] The amount of flame retardant varies depending on the required level of flame retardancy, but is preferably in the range of 1 to 30 parts by mass, and more preferably in the range of 5 to 25 parts by mass, per 100 parts by mass of the total resin components contained in the polyphenylene ether resin composition. When the amount of flame retardant is 1 part by mass or more, the fluidity and flame retardancy of the polyphenylene ether resin composition are improved, when it is 30 parts by mass or less, the flame retardancy of the polyphenylene ether resin composition is sufficient, and when it is 30 parts by mass or less, the balance between fluidity, release properties, and burr suppression is improved.

[0057] (Other additives) In addition to the various materials mentioned above, the polyphenylene ether resin composition may also contain, as needed, other thermoplastic resins, various additives commonly added to thermoplastic resins, such as heat stabilizers, antioxidants, UV absorbers and other stabilizers, conductivity imparters, antistatic agents, colorants such as pigments and dyes, and mold release agents. Examples of thermoplastic resins used as additives include polystyrene, high-impact polystyrene, polyamide, and polyolefin. Note that the thermoplastic resins used as additives are resins other than the polyphenylene ether and polyethylene terephthalate mentioned above.

[0058] The specific preferred amounts of other additive components are preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less, when the entire polyphenylene ether resin composition is considered to be 100% by mass. Furthermore, the total amount of other additive components is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, when the entire polyphenylene ether resin composition is considered to be 100% by mass.

[0059] (Crystallizing agent) The above polyphenylene ether resin composition may contain a nucleating agent. By including a nucleating agent for PET, the release properties can be further improved when PET is used as the crystalline resin, and the dimensional accuracy of the thin-walled portion can also be improved. As a nucleating agent for PET crystals, there are no particular limitations as long as it is an additive that increases the rate of PET crystal nuclei formation, but examples include inorganic nucleating agents such as silica, kaolin, talc, Hytron, and boron nitride; organic nucleating agents derived from rosin-modified materials; organic carboxylic acid metal salts such as calcium stearate, aluminum stearate, dipotassium succinate, calcium benzoate, disodium phthalate, trisodium trimellitate, and tetrapotassium pyromellitate; and high-melting-point polymers such as polyphenylene sulfide ketone, nylon 46, and polybutylene terephthalate (PBT). Among these, inorganic nucleating agents are preferred, and talc is more preferred. More specifically, talc can be a plate-like crystal with an average particle size of 1 to 50 μm, mainly composed of hydrated magnesium silicate (SiO2: 58 to 64%, MgO: 28 to 32%, Al2O3: 0.5 to 5%, Fe2O3: 0.3 to 5%). The average particle size of the talc is more preferably 10 to 40 μm, and even more preferably 20 to 35 μm. The shape of the PET crystal nucleating agent can be measured in the same way as the measurement of the average length of the inorganic filler described above. Surface treatment may be applied using silane coupling agents, titanate coupling agents, aliphatic metal salts, etc. Organic treatment may be applied using ammonium salts, etc. by intercalation method. Binder treatment may be applied using resins such as urethane resin and epoxy resin.

[0060] The appropriate content of the nucleating agent is not particularly limited, as it is generally determined by the resin and type of nucleating agent used. However, it is usually used in the range of 0.1% to 3% relative to the weight of the crystalline resin (e.g., PET).

[0061] <Resin molded products> The above-mentioned resin molded product is not particularly limited, but it is preferable that its shape and physical properties satisfy the following conditions.

[0062] The manufacturing method of this embodiment is less prone to molding defects. Molding defects are more likely to occur in resin molded products where the projected area is large relative to the thickness, and are particularly likely to occur in resin molded products where the surface area is large relative to the thickness. According to the manufacturing method of this embodiment, molding defects are less likely to occur even in resin molded products where the surface area is large relative to the thickness. The manufacturing method of this embodiment is preferable because it is less likely to cause molding defects even when the shape of the resin molded product is such that X = 125 or more in the formula defined below. (Ratio of surface area A to thickness T: X) (cm²) 2 / cm)=Surface area A(cm 2 ) / Thickness T (cm)

[0063] The coefficient of friction of the surface of the above-mentioned resin molded product is preferably 0.2 or less. The applications of the resin molded product manufactured in this embodiment are not particularly limited, but it can be used in a wide variety of everyday products. A coefficient of friction of 0.2 or less results in good surface smoothness and visual texture, which improves the design of the product and the user's feel during use, and tends to increase the product's value.

[0064] The above-mentioned resin molded product preferably has a certain level of heat resistance to prevent product defects. It is also preferable that the heat deflection temperature (1.8 MPa load) of the resin molded product be 140°C or higher. A high heat deflection temperature prevents deformation of the molded product during long-term use, even in power supply peripheral components and products exposed to heat cycles, and tends to make it suitable for use as internal components in electrical products and the like. [Examples]

[0065] The embodiment will be described below with reference to specific examples and comparative examples. However, this embodiment is not limited to these.

[0066] The raw materials and methods for measuring physical properties used in the examples and comparative examples are shown below.

[0067] <Ingredients> (Shredded PET) Used PET beverage bottles from households were collected and thoroughly washed with water. After drying the bottles completely, they were crushed using a crusher to a size of approximately 10-20 mm square. For use in mixing, the crushed PET material 1 was used after being dried at 100°C for 3 hours. Additionally, PET beverage bottles collected from another household were crushed and dried in the same manner as PET crushed product 1, and used as PET crushed product 2. (PPE) Polyphenylene ether (PPE) obtained by oxidative polymerization of 2,6-xylenol (intrinsic viscosity 0.54 dL / g (chloroform solution, measured at 30°C)). (Inorganic filler) Glass fiber (average diameter 30 μm, average length 3 mm) Glass flakes (average plate diameter 600 μm, average minor diameter 100 μm, average major diameter 300 μm, aspect ratio of average major diameter L1 to average minor diameter L2 (L1 / L2) 3, average aspect ratio of average major diameter L1 to average thickness T (L1 / T) 10) (Emulsifying and dispersing agent) Styrene-glycidyl methacrylate copolymer (monomer ratio of copolymer: styrene 95% by mass, glycidyl methacrylate 5% by mass, weight-average molecular weight 110,000).

[0068] <Method for measuring physical properties> (Weight average molecular weight) The weight-average molecular weight of the raw materials, PET and polyphenylene ether-based resin compositions, was measured by the following method. The sample was weighed into a 30 mL vial, and HFIP (hexafluoro-2-propanol) was added to prepare a 0.1 w / w% solution. The HFIP solution was filtered through a 0.2 μm membrane filter and subjected to GPC measurement (60 μl). A calibration curve was created using PMMA particles as a standard substance for weight-average molecular weight, and the molecular weight was measured.

[0069] (Exothermic reaction during DSC crystallization) A device consisting of a TA Instruments DSC2500 connected to a cooling unit was used. 0.01 to 0.03 mg of the polyphenylene ether resin composition to be measured was weighed into a designated aluminum pan, covered with an aluminum lid, sealed with a designated press, and then set in the measurement unit. An aluminum pan without resin and a pressed aluminum lid were set in the reference unit. The temperature was raised from 23°C to 350°C at a heating rate of 20°C / min, held at 350°C for 3 minutes, and then cooled to 80°C at 20°C / min. The amount of heat generated during crystallization at the first cooling stage (J / g) was determined from the area value of the exothermic peak that appeared during the first cycle.

[0070] (Coefficient of friction) Using an Okura Industry DFT-1 dynamic friction tester and a Shibaura Machine Industry (Toshiba Machine) EC100-SXII injection molding machine, a 4mm thick ISO-A dumbbell was injection molded with a resin temperature of 280°C and a mold temperature of 80°C. The frictional force generated between the flow direction of the 4mm thick ISO-A dumbbell and a 0.5mm diameter SUS ball was evaluated. The ISO-A dumbbell was fixed to a sliding stage using a screw-in jig. A metal jig was used to fix a metal SUS ball to the sliding part, and after adjusting the load to 0N, a load of 500g was applied for measurement. The sliding was performed 5000 times under conditions of 30mm / sec and 20mm, and the average value was used as the measurement value.

[0071] (940nm light transmittance) Under injection molding conditions equivalent to those used for the friction coefficient measurement sample described above, strip-shaped test pieces were injection molded in a 60 × 20 × 2 mm thick mold. Using a JASCO V650 spectrophotometer, the measurement light wavelength was set to 940 nm, and the light transmittance was confirmed using an ISV-722 transmission unit via an integrating sphere.

[0072] (Temperature of deflection under load) The polyphenylene ether resin compositions obtained in each example were used to form 4mm thick ISO-A dumbbells under injection molding conditions equivalent to those used for the friction coefficient measurement samples. Strips cut to 80 × 10 × 4mm thick were then annealed at 100°C for 8 hours in a dryer. After that, the strips were placed in a load deflection temperature measuring device (manufactured by Yasuda Seiki Co., Ltd.), and the temperature at which deformation occurred under a load of 1.80 MPa was measured using a method compliant with ISO 75.

[0073] <Examples 1-9, Comparative Examples 1-3> (Manufacturing of each polyphenylene ether resin composition) For each example and comparative example, the polyphenylene ether-based resin compositions and resin molded articles were obtained by weighing the above raw materials according to the mixing ratio (parts by mass) shown in Table 1, and then melt-extruding them using a Japan Steel Works Ltd. TEX65 twin-screw extruder at a screw rotation speed of 471 rpm and a set temperature of 300°C. In the above melt-extrusion, raw materials other than the inorganic filler were fed from a hopper into the twin-screw extruder, and the inorganic filler was fed in through a vent port via side feed. The obtained polyphenylene ether-based resin composition pellets were dried at 100°C for 3 hours and then subjected to injection molding.

[0074] (Injection molding of polyphenylene ether-based resin compositions) Using the polyphenylene ether-based resin composition described above, the resulting resin composition pellets were supplied to a screw-in-line injection molding machine (manufactured by Toshiba Machine Co., Ltd., product name "EC75SXII injection molding machine"), and molded at a cylinder temperature of 270°C and a mold temperature of 60°C, with a thickness of 50 × 50 × 2 mmt (as shown in Table 1, the ratio of surface area A to thickness T of the resin molded product (A / T) was 125 cm²). 2 Examples / comparative examples of / cm), 60×60×2mmt (In Table 1, the ratio of surface area A to thickness T of the resin molded product (A / T) is 180cm²) 2 Examples / comparative examples of / cm), 100×100×2mmt (In Table 1, the ratio of surface area A to thickness T of the resin molded product (A / T) is 500cm²) 2Examples / comparative examples of / cm), 150×150×2mmt (In Table 1, the ratio of surface area A to thickness T of the resin molded product (A / T) is 1125cm² 2 Test specimens of the examples / comparative cases (in cm) were injection molded.

[0075] <Rating> (Evaluation of cooling time and release properties) During the manufacturing of the above-mentioned molded product, the injection speed was set to 100 mm / second, the holding pressure applied after resin injection to 80 MPa, the holding time to 5 seconds, and the cooling time while the screw was retracted for metering to 60 seconds. Ten sacrificial shots were performed. Subsequently, when the cooling time was set to 60 seconds, 120 seconds, 180 seconds, 240 seconds, and 300 seconds, the presence or absence of adhesion to the mold was checked during mold opening and ejection.

[0076] (Checking the amount of warping deformation) The resulting resin molded product was deformed (mm) using a Mitsutoyo Crysta-Apex V2000.

[0077] (Bali's evaluation) The obtained resin molded product was evaluated by visually observing the upper part of the flat plate, the side opposite the flow tip, and the gate side, and checking whether burrs could be observed in the area corresponding to the edge of the mold.

[0078] [Table 1]

[0079] <Overall Judgment> The results are shown in Table 1. In all of the examples, molding was possible within 180 seconds without sticking or burrs during demolding, and the amount of warpage was kept to a minimum. The 940nm light transmittance, friction coefficient, and load deflection temperature were also within a favorable range, resulting in good quality resin molded products. However, in the comparative examples, defects such as molding defects or insufficient heat resistance occurred under one or more conditions. This demonstrates the effectiveness of this embodiment.

Claims

1. A method for producing a resin molded product, comprising the step of injection molding a polyphenylene ether-based resin composition to obtain a resin molded product, The polyphenylene ether-based resin composition comprises polyphenylene ether, polyethylene terephthalate, and an inorganic filler. A method for manufacturing a resin molded product, characterized in that the amount of crystallization heat during the first cooling of the first cycle, measured by differential scanning thermal analysis (DSC) of the polyphenylene ether resin composition, is 23 J / g or more and 45 J / g or less, after raising the temperature from 23°C to 350°C at a heating rate of 20°C / min, holding at 350°C for 3 minutes, and then cooling down to 80°C at 20°C / min.

2. The ratio of the surface area A to the thickness T of the aforementioned resin molded product (A / T) is 125 cm². ２ A method for manufacturing a resin molded article according to claim 1, wherein the length is 1 cm or more.

3. The method for manufacturing a resin molded product according to claim 1 or 2, wherein the amount of warpage deformation of the resin molded product is 2.3 mm or less.

4. A method for producing a resin molded article according to any one of claims 1 to 3, wherein the total content of polyphenylene ether, polyethylene terephthalate, and inorganic filler is 99 to 100% by mass, based on 100% by mass of the polyphenylene ether-based resin composition.

5. A method for producing a resin molded article according to any one of claims 1 to 4, wherein the weight-average molecular weight of the polyethylene terephthalate is 80,000 or more.

6. A method for producing a resin molded article according to any one of claims 1 to 5, wherein the weight-average molecular weight of the polyphenylene ether resin composition is 50,000 or more.

7. A method for producing a resin molded article according to any one of claims 1 to 6, wherein the mass ratio of polyethylene terephthalate to 100 parts by mass of the total mass of the polyphenylene ether and the polyethylene terephthalate in the polyphenylene ether resin composition is 30 to 90 parts by mass.

8. The method for manufacturing a resin molded article according to any one of claims 1 to 7, wherein the polyethylene terephthalate is obtained by recovering and crushing a finished resin molded article as part of the raw material.

9. A method for producing a resin molded article according to any one of claims 1 to 8, wherein the inorganic filler is contained in an amount of 20 to 60% by mass with respect to 100% by mass of the polyphenylene ether resin composition.

10. A method for producing a resin molded article according to any one of claims 1 to 9, wherein the transmittance of the polyphenylene ether resin composition at 2 mmt and 940 nm is 30% or more and 100% or less.

11. A method for manufacturing a resin molded article according to any one of claims 1 to 10, wherein the coefficient of friction of the surface of the resin molded article is 0.2 or less.

12. A method for manufacturing a resin molded article according to any one of claims 1 to 11, wherein the temperature of deflection under load (ISO 75) of the resin molded article is 140°C or higher.

13. It contains polyphenylene ether, polyethylene terephthalate, and inorganic fillers. A polyphenylene ether-based resin composition characterized by having a crystallization exothermic amount of 23 J / g or more and 45 J / g or less during the first cooling cycle of the first cycle, which is measured by differential scanning thermal analysis (DSC) in which the temperature is raised from 23°C to 350°C at a heating rate of 20°C / min, held at 350°C for 3 minutes, and then cooled to 80°C at 20°C / min.

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