Polyester resin composition

Abstract

To provide a polyester resin composition that has a high crystallization rate of polyester resin and excellent molding cycle, the polyester resin composition capable of forming a molding having excellent mechanical properties such as heat resistance and rigidity.SOLUTION: A polyester resin composition comprises a polyester resin, a filler, and a filler dispersant and / or a filler binder. In the polyester resin composition, the content of the filler is 20 wt.% to 70 wt.%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyester resin composition. [Background technology]

[0002] Conventionally, resin compositions containing polyester-based resins (polyester-based resin compositions) have been known as one type of resin material. Polyester-based resins can have a slow crystallization rate, and the solidification rate after melting a resin composition containing such a resin is slow, making pelletizing difficult. Furthermore, after pelletizing or during the drying process of the pellets, the pellets may fuse together, causing blocking. In addition, injection molding poses the problem of a long molding cycle. Furthermore, sheet molding, extrusion molding, and other processes can only be performed in an amorphous state, resulting in problems such as reduced heat resistance.

[0003] To address this issue, a known method involves blending a filler that can act as a crystallization nucleating agent with a polyester resin to increase the crystallinity of the polyester resin. Polyester resins with increased crystallinity offer various advantages, such as shorter molding cycles, improved heat resistance, and improved modulus of elasticity (rigidity). Increasing the frequency of crystal nucleation is an effective way to increase the crystallinity of polyester resins. To increase the crystallinity of polyester resin compositions, particularly polyester resins with a significantly slow crystal growth rate, such as polyethylene terephthalate, requires increasing the filler particle concentration and shortening the inter-filler distance by increasing the filler content and / or reducing the particle size. However, powdered fillers generally have low bulk density and poor powder flowability, making it difficult to accurately feed high-concentration fillers into melt-kneading devices such as extruders at high feed rates. This can lead to problems such as difficulty in producing resin compositions with sufficiently high filler particle concentrations with stable compositional accuracy and high throughput.

[0004] Furthermore, when a polyester resin composition contains a high concentration of filler, there is a problem in that impurities contained in the filler (e.g., Fe2O3, CaO, Al2O3 impurities) and / or moisture adhering to the filler may promote hydrolysis of the polyester resin. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a polyester-based resin composition that has a fast crystallization rate of the polyester-based resin and an excellent molding cycle, and that can form a molded article that is excellent in mechanical properties such as heat resistance and rigidity. [Means for solving the problem]

[0006] The polyester-based resin composition of the present invention is a polyester-based resin composition comprising a polyester-based resin, a filler, and a filler dispersant and / or a filler binder, and the content of the filler in the polyester-based resin composition is 20% by weight to 70% by weight. In one embodiment, the filler dispersing agent is at least one selected from the group consisting of polyhydric alcohol fatty acid esters, fatty acid amides, polyglycerin fatty acid esters, condensed hydroxy fatty acids, and alcohol esters of condensed hydroxy fatty acids. In one embodiment, the filler binder is at least one selected from the group consisting of polyolefin-based resins, polyvinyl alcohol-based resins, polyalkylene glycol-based resins, polyvinylpyrrolidone-based resins, polyamide-based resins, acrylic-based resins, urethane-based resins, and epoxy-based resins. In one embodiment, the filler binder is a polyolefin resin. In one embodiment, the total content of the filler dispersant and the filler binder in the polyester resin composition is 0.1% by weight to 10% by weight. In one embodiment, the polyester resin composition contains talc and / or mica as the filler. In one embodiment, the polyester resin composition further comprises an impact modifier. In one embodiment, the polyester resin composition further comprises a hydrolysis resistance improver, and the hydrolysis resistance improver is a compound having at least one functional group selected from the group consisting of a carbodiimide group, an oxazoline group, and an epoxy group. In one embodiment, the polyester resin composition has a flexural modulus at 23°C of 3,000 MPa or more. In one embodiment, the polyester resin composition has a deflection temperature under load of 150° C. or higher. According to another aspect of the present invention, there is provided a method for producing a polyester-based resin composition, comprising melt-kneading the polyester-based resin and a filler granule, the filler granule containing the filler and the filler dispersant and / or filler binder, and the filler content in the filler granule is 80 to 99.9 parts by weight per 100 parts by weight of the filler granule. According to yet another aspect of the present invention, there is provided an injection-molded article formed from the polyester resin composition. According to yet another aspect of the present invention, there is provided an extrusion molded article formed from the above polyester resin composition. According to yet another aspect of the present invention, there is provided a sheet-like shaped article formed from the polyester resin composition. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a polyester-based resin composition that has a fast crystallization rate of the polyester-based resin and an excellent molding cycle, and that can form a molded article that has excellent mechanical properties such as heat resistance and rigidity. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. Polyester resin composition A-1. Overview of polyester resin compositions The polyester resin composition of the present invention contains a polyester resin, a filler, and a filler dispersant and / or a filler binder. The content of the filler in the polyester resin composition is 20% by weight to 70% by weight. The "filler content," as well as the content of each component in the "polyester resin content," "filler content," "filler dispersant content," and "filler binder content" described below, are each weight percentages based on the total solid content in the polyester resin composition.

[0009] The polyester resin composition of the present invention can contain a high concentration of filler, resulting in a fast crystallization rate of the polyester resin and an excellent molding cycle. Furthermore, the polyester resin composition can favorably possess properties inherent to the polyester resin, and can form molded articles with excellent mechanical properties, such as heat resistance and rigidity. Furthermore, by including a filler together with a filler dispersant and / or a filler binder, the effects of adding the filler (e.g., functioning as a crystallization nucleating agent) can be more effectively achieved than before.

[0010] Furthermore, the polyester resin composition of the present invention contains a filler dispersant and / or a filler binder, which can suppress hydrolysis of the polyester resin. Such a polyester resin composition has a high degree of freedom in filler selection and is advantageous from the viewpoint of improving the molding cycle.

[0011] In one embodiment, the filler and filler dispersant and / or filler binder are added in the form of filler granules. In this embodiment, a filler granule containing the filler and filler dispersant and / or filler binder is formed, and then the filler granules are mixed with a polyester resin (e.g., by melt kneading), thereby obtaining the polyester resin. By employing such a production method, the workability of filler addition (feed characteristics (supply amount and stability)) and filler dispersibility are significantly improved, making it possible to incorporate a high filler content with good productivity.

[0012] The deflection temperature under load of the polyester resin composition is preferably 150° C. or higher, more preferably 160° C. to 250° C., and even more preferably 170° C. to 240° C. The deflection temperature under load of the polyester resin composition is measured using a predetermined sample formed using the polyester resin composition. The method for measuring the deflection temperature under load will be described later.

[0013] The Charpy impact strength of the polyester resin composition at 23°C is preferably 1.0 kJ / m 2 More preferably, 1.5 kJ / m 2 More preferably, it is 2.0 kJ / m or more. 2 The higher the Charpy impact strength, the better, but the upper limit is, for example, 10.0 kJ / m 2 The Charpy impact strength of the polyester resin composition at 23°C is measured using a predetermined sample formed using the polyester resin composition. The method for measuring the Charpy impact strength will be described later.

[0014] The flexural modulus of the polyester resin composition at 23°C is preferably 3,000 MPa or more, more preferably 4,000 MPa or more, and even more preferably 5,000 MPa or more. The higher the flexural modulus, the better, but the upper limit is, for example, 20,000 MPa. The flexural modulus of the polyester resin composition at 23°C is measured using a predetermined sample formed using the polyester resin composition. The method for measuring the flexural modulus will be described later.

[0015] The flexural strength of the polyester resin composition at 23°C is preferably 50 MPa or more, more preferably 60 MPa or more, and even more preferably 70 MPa or more. The higher the flexural strength, the better, but the upper limit is, for example, 200 MPa. The flexural strength of the polyester resin composition at 23°C is measured using a predetermined sample formed using the polyester resin composition. The method for measuring the flexural strength will be described later.

[0016] A-2. Polyester resin The polyester resin can be obtained by polycondensation of a dicarboxylic acid and a diol, and any suitable method can be used as the production method.

[0017] Any suitable dicarboxylic acid may be used, such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, diphenylcarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracenedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, azelaic acid, dimer acid, sebacic acid, suberic acid, and dodecadicarboxylic acid.

[0018] Any suitable diol may be used, such as ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis(4-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)sulfone.

[0019] The dicarboxylic acid component and diol component constituting the polyester-based resin may each be used alone or in combination of two or more. The polyester-based resin may also contain other acid components such as trimellitic acid, other hydroxyl group components such as trimethylolpropane, etc. Polyester-based resins such as polyethylene terephthalate copolymerized with isophthalic acid as the dicarboxylic acid and / or 1,4-cyclohexanedimethanol as the diol within a range that provides crystallinity can also be used.

[0020] Any appropriate polyester resin can be used as the polyester resin, such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene naphthalate, and polybutylene naphthalate.

[0021] The intrinsic viscosity of the polyester resin is preferably 0.3 to 1.5, more preferably 0.4 to 1.2, and even more preferably 0.5 to 1.0. Within these ranges, a polyester resin composition having desirable properties and excellent moldability can be obtained. The intrinsic viscosity can be measured according to JIS K7367.

[0022] The content of the polyester resin in the polyester resin composition is preferably 30 to 80% by weight, more preferably 40 to 70% by weight. Within this range, the effect of adding the filler (for example, function as a crystallization nucleating agent) is preferably exhibited, and a polyester resin composition can be obtained that can preferably exhibit the properties inherent to the polyester resin.

[0023] The polyester resin may contain a polyester resin that can act to bind the filler.

[0024] A-3. Filler As the filler, any appropriate filler can be used depending on the properties required for the polyester resin composition and / or the molded article obtained from the polyester resin composition. Only one type of filler may be used, or two or more types may be used in combination.

[0025] Preferably, talc and / or mica are used as the filler. These fillers can function favorably as crystallization nucleating agents that promote the crystallization of resins in polyester-based resin compositions. In the present invention, talc and / or mica can be contained in high concentrations, which is advantageous in that the crystallization rate and degree of crystallization of the polyester-based resin are increased.

[0026] Talc and mica have a layered structure and weak interlayer bonding strength, making them prone to peeling. Fine particles are often used as compounding agents for plastics, improving heat resistance, dimensional stability, etc. The impurity content varies depending on the source, but those made from high-quality ores with few impurities are preferred, and it is preferable for the total amount of metal impurities, such as aluminum oxide and iron oxide, to be less than 1%.

[0027] The number average particle size of the filler can be any appropriate particle size. The number average particle size of the filler is preferably 0.1 μm to 40 μm, more preferably 0.5 μm to 10 μm, and even more preferably 1 μm to 8 μm. When the filler functions as a crystallization nucleating agent, the particle size of the filler is preferably small. When the filler functions as a crystallization nucleating agent (for example, when talc and / or mica is used), the number average particle size of the filler is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 5 μm or less. The size of the filler can be determined by laser diffraction.

[0028] As described above, the content of the filler in the polyester resin composition is 20% by weight to 70% by weight. The content of the filler in the polyester resin composition is preferably 20% by weight to 60% by weight, and more preferably 30% by weight to 55% by weight. Within this range, the effects of the present invention become more pronounced.

[0029] A-4. Filler dispersant A surfactant is preferably used as the filler dispersant. The hydrophilic / hydrophobic balance of the filler dispersant (surfactant) can be controlled by adjusting the degree of esterification of the compound that becomes the filler dispersant, the type of fatty acid (presence or absence of hydroxyl groups, saturated or unsaturated fatty acid, alkyl chain length), and the degree of polymerization. The filler dispersant acts as a surfactant, thereby enhancing the dispersibility of the filler.

[0030] Examples of the filler dispersant include fatty acids, fatty acid metal salts, fatty acid sulfonates, fatty acid amides, acrylamides, polyhydric alcohol fatty acid esters, polyglycerin fatty acid esters, etc. One type of filler dispersant may be used alone, or two or more types may be used in combination.

[0031] In one embodiment, the filler dispersing agent is at least one selected from the group consisting of polyhydric alcohol fatty acid esters, fatty acid amides, polyglycerin fatty acid esters, condensed hydroxy fatty acids, and alcohol esters of condensed hydroxy fatty acids.

[0032] The polyhydric alcohol fatty acid ester is an ester compound composed of a polyhydric alcohol and a fatty acid. Examples of the polyhydric alcohol fatty acid ester include esters of polyhydric alcohols such as pentaerythritol and glycerin with fatty acids having 8 or more carbon atoms (preferably 8 to 24 carbon atoms, more preferably 10 to 22 carbon atoms).

[0033] The fatty acid amide is a compound having a structure formed by dehydration condensation of a fatty acid with ammonia or a primary or secondary amine. Examples of the fatty acid amide include saturated fatty acid monoamides such as lauric acid amide, palmitic acid amide, stearic acid amide, and behenic acid amide.

[0034] The polyglycerol fatty acid ester is an ester compound composed of polyglycerol and a fatty acid, and examples of the polyglycerol fatty acid ester include diglycerol palmitate, diglycerol stearate, diglycerol oleate, decaglycerol palmitate, decaglycerol stearate, and decaglycerol oleate.

[0035] The content of the filler dispersant in the polyester resin composition is preferably 0.1 to 10% by weight, more preferably 1 to 8% by weight, and even more preferably 1 to 5% by weight. Within this range, the effect of adding the filler (for example, function as a crystallization nucleating agent) is preferably exhibited, and a polyester resin composition can be obtained that can preferably exhibit the properties inherent to the polyester resin.

[0036] The total content of the filler dispersant and filler binder in the polyester resin composition is preferably 0.1 to 10% by weight, more preferably 1 to 8% by weight, and even more preferably 1 to 5% by weight. Within this range, the effect of the filler addition (for example, its function as a crystallization nucleating agent) can be favorably exhibited, and a polyester resin composition can be obtained that favorably exhibits the properties inherent in the polyester resin. Note that the "total content of the filler dispersant and filler binder" refers to the content of the filler binder when the polyester resin composition does not contain a filler dispersant, and refers to the content of the filler dispersant when the polyester resin composition does not contain a filler binder.

[0037] A-5. Filler binder The filler binder can have the function of binding fillers together. Furthermore, the use of the filler binder can improve the dispersibility of the filler. Furthermore, the filler binder can exhibit the effect of suppressing the hydrolysis of the polyester resin. Furthermore, when the filler is added in the form of filler granules, the filler binder is used for the purpose of obtaining granules having appropriate bulk density and disintegration strength. Furthermore, by selecting a suitable filler binder, the productivity of the filler granules can be improved.

[0038] Resins are preferably used as the filler binder, and water-soluble or water-dispersible resins are particularly preferred, but polysaccharides, clay minerals, and the like can also be used. The filler binder can be at least one selected from the group consisting of polyolefin-based resins, polyvinyl alcohol-based resins, polyalkylene glycol-based resins, polyvinylpyrrolidone-based resins, polyamide-based resins, acrylic-based resins, urethane-based resins, and epoxy-based resins. Polyolefin-based resins are particularly preferred. As the polyolefin-based resin, polyethylene-based resins and / or polypropylene-based resins can be preferably used.

[0039] Specific examples of the polyethylene resin used as a filler binder include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyolefin elastomers (POE), polyolefin copolymers (e.g., ethylene-butene, ethylene-octene, etc.), modified polyolefins (e.g., modified products of maleic anhydride, acrylic acid, etc.), and functional polyolefin copolymers including polyolefin-based ionomers.

[0040] Specific examples of the polypropylene resin used as a filler binder include homopolypropylene (h-PP), block polypropylene (b-PP), random polypropylene (r-PP), polypropylene copolymer, and modified polypropylene (e.g., modified with maleic anhydride, acrylic acid, etc.).

[0041] Specific examples of the polyvinyl alcohol resin used as a filler binder include ethylene-vinyl alcohol copolymer (EVOH; EVAL (registered trademark) manufactured by Kuraray Co., Ltd.), butenediol-vinyl alcohol copolymer (BVOH; Nichigo G Polymer (registered trademark) manufactured by Mitsubishi Chemical Corporation), etc.

[0042] Commercially available filler binders may be used. Examples of commercially available binders include Chemipearl (registered trademark) manufactured by Mitsui Chemicals, Inc., HYPOD (registered trademark) manufactured by Dow Chemical Company, AQUACER (registered trademark) manufactured by BYK Japan, ZAIKXEN, SEPOLJON, and SEPOLEX (registered trademark) manufactured by Sumitomo Seika Chemicals, Michem (registered trademark) manufactured by Michelman Japan, Bondic (registered trademark) manufactured by DIC Corporation, and Saivinol and Saiden Glue (registered trademark) manufactured by Saiden Chemical Industries, Ltd. Other preferred examples include ethylene-vinyl alcohol copolymer (EVOH; EVAL (registered trademark) manufactured by Kuraray Co., Ltd.) and butenediol-vinyl alcohol copolymer (BVOH; Nichigo G-Polymer (registered trademark) manufactured by Mitsubishi Chemical Corporation). Other preferred examples include aqueous sulfopolyester dispersions sold under the trademark Eastman AQ® by Eastman Chemical Company, and the salt of hexane-1,6-diamine and adipic acid (AH salt) sold by Ascend Performance, which is diluted with water to form an aqueous polymer dispersion.

[0043] The content of the filler binder in the polyester resin composition is preferably 0.1 to 10% by weight, more preferably 1 to 8% by weight, and even more preferably 1 to 5% by weight.

[0044] A-6. Other ingredients The polyester resin composition may further contain any other appropriate components (additives) as needed, such as antioxidants, light stabilizers, foaming agents, ultraviolet absorbers, antiblocking agents, heat stabilizers, impact modifiers, antibacterial agents, compatibilizers, plasticizers, tackifiers, processing aids, lubricants, coupling agents, flame retardants, oxygen absorbers, colorants, lubricants, release agents, antistatic agents, antifogging agents, and flowability improvers.

[0045] In one embodiment, the polyester resin composition includes an impact modifier. Any appropriate resin can be used as the impact modifier. Examples of impact modifiers include butadiene resins, acrylic resins, silicone-acrylic core-shell rubbers, and styrene elastomers. The content of the impact modifier in the polyester resin composition is preferably 5% by weight to 30% by weight, and more preferably 10% by weight to 20% by weight.

[0046] In one embodiment, the polyester resin composition includes a hydrolysis resistance improver. The hydrolysis resistance improver refers to an additive that inhibits hydrolysis of the polyester resin by removing substances that promote hydrolysis by reacting with active hydrogen groups generated by decomposition of the ester resin in the presence of acid, heat, or water. The hydrolysis resistance improver may be, for example, a compound having at least one functional group selected from the group consisting of a carbodiimide group, an oxazoline group, and an epoxy group. Commercially available hydrolysis resistance improvers may be used, and examples include Carbodilite LA-1 and HMV-5CA-LC (registered trademark) manufactured by Nisshinbo Chemical Inc. The content of the hydrolysis resistance improver in the polyester resin composition is preferably 0.05% by weight to 5% by weight, and more preferably 0.1% by weight to 2% by weight.

[0047] B. Method for producing polyester resin composition The polyester resin composition can be produced by any appropriate method. In one embodiment, the polyester resin composition can be obtained by melt-kneading a polyester resin, a filler, and a filler dispersant and / or a filler binder. Preferably, the polyester resin composition can be obtained by melt-kneading the polyester resin and a filler granule (a granule containing the filler, the filler dispersant and / or the filler binder). Any appropriate method can be used for melt-kneading. For example, a kneader, a Banbury mixer, a roll, or a single-screw or multi-screw extruder having two or more screws can be used. Preferably, a twin-screw extruder is used. The melt-kneaded composition can be pelletized.

[0048] In one embodiment, the polyester resin composition is obtained by melt-kneading the filler granules containing the filler, a filler dispersant, and / or a filler binder with the polyester resin. This manufacturing method significantly improves the workability of filler addition and filler dispersion, enabling a high filler content. More specifically, the filler granules exhibit excellent stability when introduced into an extruder or other device, eliminating feed necks. Therefore, the use of the filler granules can dramatically improve the productivity of polyester resin compositions (compound processing rate per hour, discharge rate (unit: kg / Hr)). Furthermore, the use of the filler granules improves filler dispersion and molding processability (fluidity), allowing polyester resin compositions obtained using the filler granules to contain the filler at a high concentration and with high dispersion. As a result, a polyester resin composition can be obtained in which the effects of the filler addition (function as a crystallization nucleating agent) can be effectively imparted.

[0049] (Filler granules) The filler granules can be produced by any appropriate method. The filler granules can be obtained, for example, by subjecting a mixture containing the filler, the filler dispersant, and / or the filler binder to a semi-wet granulation method. It is more preferable to use a filler dispersant and a filler binder in combination. That is, the filler granules can be obtained by subjecting a mixture containing the filler, the filler dispersant, and the filler binder to a semi-wet granulation method. The filler, filler dispersant, and filler binder described in Section A can be used. The filler binder can function as a binder.

[0050] The content of the filler in the filler granules is preferably 80 to 99.9 parts by weight, more preferably 82 to 99 parts by weight, even more preferably 85 to 98 parts by weight, particularly preferably 87 to 97 parts by weight, and most preferably 90 to 96 parts by weight, relative to 100 parts by weight of the total solid content of the filler granules.

[0051] In one embodiment, the filler binder is mixed in the form of an aqueous solution or dispersion containing the filler binder.

[0052] In one embodiment, the method for producing the filler granules includes a mixing step of mixing the filler binder and the filler dispersant, a granulation step of granulating the mixture obtained through the mixing step to obtain a granule precursor, and a drying step of drying the granule precursor.

[0053] In the mixing step, water may be further mixed in. The water to be added is not particularly limited, and examples thereof include tap water, distilled water, ion-exchanged water, hard water, and soft water.

[0054] The amount of water mixed is usually 1 to 30 parts by weight, preferably 3 to 25 parts by weight, and more preferably 5 to 20 parts by weight, relative to 100 parts by weight of the filler in the filler granules.

[0055] In the mixing step, the components are preferably blended at room temperature and homogenized using any suitable mixer, such as a Henschel mixer, a powder kneader (KDH, KDA, CKD, CPM) (Dalton), a Spartan mixer (SPM) (Dalton), or an SP granulator (SPG) (Dalton).

[0056] The mixing time in the mixing step can be any appropriate time depending on the type of components, the type of mixer, the component blending ratio, etc. The mixing time in the mixing step is set so that each component is uniformly dispersed. A high-speed mixer such as a Henschel mixer or a Spartan mixer can be used for processing in 1 to 10 minutes. On the other hand, a powder kneader may require processing times of several minutes to 60 minutes.

[0057] In the granulation step, a compression granulation method is preferably used. Also, in the granulation step, a semi-wet granulation method can be preferably used. Examples of the compression granulation method / semi-wet granulation method include a disk pelleting method, a tableting method, and a briquetting method. From the viewpoint of the balance between productivity and the quality of the resulting filler granules, the disc pelletizer method is preferably employed.

[0058] The basic structure of a disc pelletizer includes one or two discs with numerous 2-30 mm holes and a roller for pressure-feeding raw materials through the holes in the disc. The raw materials supplied between the disc and roller, or between two discs, are forced into the holes in the disc as the roller rotates, forming a cylindrical extrudate. The disc holes are tapered, and compressive stress is applied from the outer periphery of the die hole as the filler mixture passes through the holes. The length of this tapered hole is called the effective length. The extruded granule precursor is cut by a cutter or the like on the back surface of the disc to obtain pellet-shaped filler granules. The length of the granule precursor (and thus the filler granules) can be adjusted by adjusting the distance between the back surface of the disc and the cutter and the rotation speed of the roller. The distance between the back surface of the disc and the cutter can be any appropriate value depending on the type of filler, and is typically in the range of 1 mm to 30 mm.

[0059] More specifically, disc pelleting methods include roller-disc die methods, roller-ring die methods, double die methods, flat die methods, etc. Commercially available disc pelleting machines include the Disc Pelletter F Series manufactured by Dalton.

[0060] Any suitable drying method can be used in the drying step. After the drying step, a filler granule from which fine powder has been removed can be obtained using a vibrating sieve or the like. Any suitable drying equipment can be used in the drying step. For example, a vibrating fluidized bed dryer is preferred because it can dry efficiently in a short time, and examples of such equipment include the VDF series vibrating fluidized bed dryers manufactured by Dalton.

[0061] Various molded articles can be produced using the polyester resin composition. For example, injection molded articles, extrusion molded articles, sheets, etc. can be produced. Furthermore, shaped articles (vacuum molded articles, press molded articles, sheet-like shaped articles, etc.) can be obtained from the sheets. Methods for producing molded articles from polyester resin compositions include, for example, injection molding, injection compression molding, profile extrusion molding, foam molding, ram extrusion molding, solidification extrusion, pipe molding, tube molding, heterogeneous molded article coating molding, injection blow molding, direct blow molding, T-die sheet or film molding, stretch molding, inflation molding, calendar molding, press molding, rotational molding, vacuum molding, pressure molding, melt spinning, etc. [Example]

[0062] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Parts and percentages are by weight unless otherwise specified.

[0063] [Production Example 1] Production of filler granules A powder kneader (Dalton, trade name "KDHJ-10"; processing capacity: 6 L) was charged with 100 parts by weight of filler (talc, Asada Flour Milling Co., Ltd., trade name "JM300"; bulk density: 0.17, average particle size: 4.7 μm; "B-1" in the table) and a filler binder (polyolefin dispersion (aqueous PE dispersion); Mitsui Chemicals, Inc., trade name "Chemipearl A100"; polyolefin solids concentration: 40 wt %; polyolefin particle density: 0.89 g / cm). 3 18 parts by weight (solids: 7.2 parts by weight) of polyolefin particles with an average particle size of 4 μm (referred to as "D-1" in the table) and 3.75 parts by weight of a filler dispersant (polyglycerin condensed hydroxy fatty acid ester, manufactured by Taiyo Kagaku Co., Ltd., trade name "Chirabazole H818" (referred to as "C-1" in the table) were added, and the mixture was stirred for 6 minutes at 30 rpm, yielding mixture A. This mixture A was charged into a disc pelleter (manufactured by Dalton, product name "Disc Pelleter F-5 / 11-175") to obtain a pellet-like talc granule precursor. The obtained granule precursor was dried at 140°C for 4 hours using a hot air circulation dryer to obtain filler granule MB-1.

[0064] [Production Example 2] Production of filler granules Filler granules B-2 were obtained in the same manner as in Production Example 1, except that the filler binder "D-1" was changed to 21 parts by weight (solid content: 3.1 parts by weight) of a 15 wt% aqueous solution of butenediol-vinyl alcohol copolymer (BVOH; manufactured by Mitsubishi Chemical Corporation, product name "Nichigo G Polymer AZF8035Q"; "D-2" in the table).

[0065] <Evaluation> The filler granules obtained in Production Examples 1 and 2 were subjected to the following evaluations. The results are shown in Table 1. In Table 1, the weight parts of the filler, filler dispersant, and filler binder are calculated from the charge composition of each component, and are shown as parts when the total amount of these solid contents is 100 weight parts. (1) Moisture content The amount of moisture remaining in the filler granules was measured using an infrared moisture meter FD-660 (manufactured by Kett Electric Laboratory) (unit: weight %). (2) Collapse strength measurement The disintegration stress of the dried filler granules was measured using a Kiya hardness tester WFP1600-B (manufactured by Shiro Sangyo Co., Ltd.). The measured value was the average value of 25 filler granules (unit: kg). (3) Bulk density The dried filler granules were allowed to fall naturally into a 1-liter measure, filled to the brim, and weighed to an exact volume of 1 liter, and the bulk density of the filler granules was calculated by measuring the weight (unit: kg / L).

[0066] [Table 1]

[0067] [Example 1] 70 parts by weight of a polyester resin (manufactured by Shinko Gosei Fibers Co., Ltd., product name "SHINPET 5522W", IV value: 0.79; in the table, "A-1") and 30 parts by weight of the filler granules (MB-1) obtained in Production Example 1 were charged into a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., product name "TEM37SS", cylinder set temperature: 260°C) and continuously melt-kneaded to produce pellets of a polyester resin composition.

[0068] [Examples 2 to 8] Pellets of a polyester resin composition were obtained in the same manner as in Example 1, except that the polyester resin and granulated filler were used in the amounts shown in Table 2. Details of the components used are shown in Table 3.

[0069] [Comparative Example 1] Pellets of polyester resin (A-1) were prepared.

[0070] Comparative Example 2 70 parts by weight of polyester resin (A-1) and 30 parts by weight of filler (JM300; B-1) were charged into a twin-screw extruder in the same manner as in Example 1 and melt-kneaded to obtain pellets of a polyester resin composition.

[0071] Comparative Example 3 45 parts by weight of polyester resin (A-1) and 55 parts by weight of filler (JM300; B-1) were charged into a twin-screw extruder in the same manner as in Example 1 and melt-kneaded to obtain pellets of a polyester resin composition.

[0072] Comparative Example 4 Pellets of a polyester resin composition were obtained in the same manner as in Example 1, except that the polyester resin and granulated filler were used in the amounts shown in Table 2.

[0073] [Table 2]

[0074] [Table 3]

[0075] <Evaluation> The polyester resin compositions obtained in Examples 1 to 8 and Comparative Examples 1 to 4 were subjected to the following evaluations. The results are shown in Table 4. The test pieces used in the load deflection measurement, bending measurement, and Charpy impact strength measurement were prepared by molding a polyester resin composition at a molding temperature of 270°C using an injection molding machine (manufactured by Toyo Machinery & Metal Co., Ltd., product name "SI-80IV-D150B" 200t) to obtain test pieces conforming to JIS K 7141. The obtained test pieces were conditioned in a constant temperature and humidity chamber for 24 hours to obtain evaluation sample A.

[0076] (1) MFR Measurements were taken using a melt indexer (manufactured by Takara Kogyo Co., Ltd.) in accordance with JIS K7210 (under conditions of 270°C and a load of 2.16 kg). (Unit: g / 10 min) (2) Deflection temperature under load The above evaluation sample A was measured using an HDT Tester 6M-2 (manufactured by Toyo Seiki Seisakusho Co., Ltd.) under JIS K7191 (load 0.45 MPa, heating rate 2°C / min) starting from a temperature of 30°C (unit: °C). (3) Bending strength The above evaluation sample A was measured using a STROGRAPH VG20-E (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K7171. The measurement temperature was 23°C (unit: MPa). (4) Flexural modulus The above evaluation sample A was measured using a STROGRAPH VG20-E (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K7171. The measurement temperature was 23°C (unit: MPa). (5) Charpy impact strength The above evaluation sample A was measured in accordance with JIS K7111 using a DIGITAL IMPACT TESTER DG-CB (manufactured by Toyo Seiki Seisakusho Co., Ltd.). The measurement temperature was 23°C. In preparing the test specimen for the Charpy impact test, the notch tip radius (R) was 0.25 mm. The hammer capacity was 2 J (unit: kJ / m 2 ) (6) DSC 5 to 10 mg of pellets of the polyester resin composition were used as a measurement sample, and the temperature was raised from an initial temperature of 30°C to 300°C at a heating rate of 10°C / min using a measuring device DSC6220 (manufactured by Seiko Instruments Inc.), and the presence or absence of a recrystallization peak was measured. The observation of an exothermic peak of recrystallization during the heating process indicates that the polyester resin composition was not sufficiently crystallized and contained many amorphous regions. (7) Injection molding Using an injection molding machine (manufactured by Toyo Machinery & Metal Co., Ltd., product name "SI-80IV-D150B" 200t), the molding temperature was 270°C, the mold temperature was 90°C, and the cooling time was 60 seconds, and an evaluation was made as to whether or not a test piece conforming to JIS K 7141 could be taken out. In the table, cases where the test piece could be taken out are indicated by ◯, and cases where it could not be taken out are indicated by ×.

[0077] [Table 4]

[0078] As is clear from the DSC evaluation results shown in Table 4 for Examples 1 to 4 and 8, polyester resin compositions of the present invention having a high filler concentration exhibit an excellent crystallization rate. They also exhibit excellent rigidity (flexural modulus). Furthermore, as is clear from the evaluation results for deflection temperature under load, polyester resin compositions of the present invention having a high filler concentration exhibit excellent heat resistance. Examples 5 to 7 are examples in which a hydrolysis resistance improver was incorporated, and a decrease in MFR was observed, suppressing hydrolysis of the polyester resin composition. As is clear from the Charpy impact strength evaluation results for Example 8, the addition of an impact improver improves Charpy impact strength. In Comparative Example 1, the crystallization rate was so slow that a molded sample for test evaluation could not be obtained. In Comparative Examples 2 and 3, the polyester resin hydrolyzed, making it impossible to obtain a molded sample for test evaluation. In Comparative Example 4, the filler concentration was outside the range of the present invention, but a recrystallization peak was observed, and the polyester resin was insufficiently crystallized, resulting in poor heat resistance (DTUL).

Claims

1. A polyester resin composition obtained by melt-kneading polyethylene terephthalate and a filler granule, The filler granules contain a filler and a filler binder, the filler binder is a polyolefin resin, the content of the filler in the polyester resin composition is 20% by weight to 70% by weight, The content of the filler in the filler granules is 82 parts by weight to 99.9 parts by weight based on 100 parts by weight of the total solid content of the filler granules. Polyester resin composition.

2. The polyester resin composition according to claim 1 , wherein the filler granules further contain a filler dispersant.

3. 3. The polyester resin composition according to claim 2, wherein the filler dispersing agent is at least one selected from the group consisting of polyhydric alcohol fatty acid esters, fatty acid amides, polyglycerin fatty acid esters, condensed hydroxy fatty acids, and alcohol esters of condensed hydroxy fatty acids.

4. 4. The polyester-based resin composition according to claim 2, wherein the total content of the filler dispersant and the filler binder in the polyester-based resin composition is 0.1% by weight to 10% by weight.

5. The polyester resin composition according to claim 1 , wherein the filler comprises talc.

6. The polyester resin composition according to claim 1 , further comprising an impact modifier.

7. further comprising a hydrolysis resistance improver; the hydrolysis resistance improver is a compound having at least one functional group selected from the group consisting of a carbodiimide group, an oxazoline group, and an epoxy group; The polyester resin composition according to any one of claims 1 to 6.

8. 8. The polyester resin composition according to claim 1, which has a flexural modulus at 23°C of 3,000 MPa or more.

9. The polyester resin composition according to claim 1 , which has a deflection temperature under load of 150° C. or higher.

10. A method for producing a polyester-based resin composition, comprising melt-kneading the polyethylene terephthalate and a filler granule, the filler granules contain the filler, the filler dispersant, and the filler binder, the filler binder is a polyolefin resin, The content of the filler in the filler granules is 82 parts by weight to 99.9 parts by weight per 100 parts by weight of the filler granules. A method for producing the polyester resin composition according to any one of claims 2 to 9.

11. An injection-molded article formed from the polyester resin composition according to any one of claims 1 to 9.

12. An extrusion molded article formed from the polyester resin composition according to any one of claims 1 to 9.

13. A sheet-like shaped product formed from the polyester resin composition according to any one of claims 1 to 9.

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