Polyester resin composition and molded article made by molding the same

Abstract

To provide a resin composition having superior abrasion resistance and rigidity, having high melt viscosity suitable for solid extrusion molding applications, and also exhibiting superior stability during residence; and a molded article made by molding the composition.SOLUTION: A polyester resin composition comprises: (A) 100 pts.wt. of a thermoplastic polyester resin (component A); (B) 10 to 70 pts.wt. of wollastonite (component B); and (C) 0.05 to 2 pts.wt. of a carbodiimide compound (component C) having a 5% weight loss temperature of 370°C or higher.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition having excellent abrasion resistance, rigidity, a high melt viscosity suitable for use in solidification extrusion molding applications, and excellent retention stability thereof, and a molded article formed by molding the same.

Background Art

[0002] Conventionally, thermoplastic polyester resins have been widely used in applications such as electric and electronic parts, household appliances, and automotive parts because of their excellent low water absorption, little change in mechanical properties and dimensional changes due to environmental changes, and stable performance. In addition, due to the characteristics of high surface hardness and excellent abrasion resistance, it is expected to be applied to mechanical element parts such as various gears and bearings.

[0003] Since there are various shapes and thicknesses of mechanical element parts, in addition to the injection molding method with excellent economy, a solidification extrusion molding method is used to create round bars and thick plate-shaped molded articles, and then cutting is performed. Means are taken to finish into the desired product shape. In solidification extrusion molding, when the resin that enters the mold from the die of the extruder is cooled and shrinks, a large strain occurs, so a resin material with a high viscosity that can withstand this is required. In addition, in order to suppress the generated strain, the extrusion speed needs to be as low as possible, and the resin material stays in the extruder in a molten state, so a property that can maintain a high melt viscosity even in such an environment is required.

[0004] In addition, the resin material used for mechanical element parts is required to have rigidity in order to reduce power transmission loss and support the loads of other parts.

[0005] Patent Document 1 discloses a resin composition for extrusion molding comprising a high-viscosity polybutylene terephthalate resin, a polymer type antistatic agent and a polyolefin resin, and Patent Document 2 discloses a resin composition comprising a polybutylene naphthalate resin and a modified ultra-high molecular weight polyethylene resin. However, since they do not contain a filler, they are insufficient in rigidity and abrasion resistance. Furthermore, there is no description regarding the melt viscosity and its retention stability. Patent Document 3 discloses a resin composition comprising a thermoplastic polyester resin, a non-fibrous inorganic filler and a compound reactive with the thermoplastic polyester resin. However, the rigidity is insufficient and there is no description regarding the abrasion resistance, melt viscosity and its retention stability.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a resin composition having excellent abrasion resistance and rigidity, having a high melt viscosity suitable for use in solidification extrusion molding applications and excellent in its retention stability, and a molded article formed therefrom.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by blending a thermoplastic polyester resin, wollastonite and a specific carbodiimide compound in a specific ratio, and thus have arrived at the present invention.

[0009] That is, the present invention is as follows. 1. A polyester resin composition containing 10 to 70 parts by weight of wollastonite (component B) and 0.05 to 2 parts by weight of a carbodiimide compound (component C) having a 5% weight loss temperature of 370°C or higher with respect to 100 parts by weight of a thermoplastic polyester resin (component A). 2. The resin composition according to item 1 above, containing 0.01 to 2 parts by weight of a silane coupling agent (component D) having one or more functional groups reactive with a thermoplastic polyester resin in the molecule with respect to 100 parts by weight of component A. 3. The resin composition according to item 2 above, wherein component D is a silane coupling agent having an epoxy group. 4. The resin composition according to any one of items 1 to 3 above, wherein component C is a cyclic carbodiimide compound represented by the following formula (1).

[0010]

Chemical formula

Chemical formula

[0011] 5. The resin composition according to any one of items 1 to 4 above, wherein component A is a polybutylene naphthalate resin having a terminal carboxyl group concentration of 40 eq / 10 3 kg or less. 6. The resin composition according to any one of items 1 to 5 above, containing 0.005 to 0.5 parts by weight of at least one phosphorus compound (component E) selected from the group consisting of phosphate esters and phosphonate esters with respect to 100 parts by weight of component A. 7. The resin composition according to any one of items 1 to 6 above, which is used for solidification extrusion molding. 8. A molded article formed by molding the resin composition according to any one of items 1 to 7 above.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a resin composition having excellent abrasion resistance, rigidity, a high melt viscosity suitable for use in solidification extrusion molding applications, and excellent retention stability, and a molded article formed by molding the same. The molded article obtained from the resin composition of the present invention can be suitably used for, for example, mechanical component parts, sliding members, gears, bearings, rollers, rails, guides, retainers, housings, covers, cams, links, ball screw members, racks, motor parts, and cases used in the fields of electric and electronic, semiconductor, automobile, industrial machinery, food, OA equipment, and architecture.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the details of the present invention will be further described.

[0014] <Regarding Component A> The thermoplastic polyester resin which is Component A of the present invention can be produced using a dicarboxylic acid component mainly composed of a dicarboxylic acid and / or an ester-forming derivative of a dicarboxylic acid and a glycol component mainly composed of a diol.

[0015] Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and diphenylether-4,4'-dicarboxylic acid; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, and oxalic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. One or more of these may be used, and they can be arbitrarily selected according to the purpose. When using two or more dicarboxylic acids, the amount of the main component dicarboxylic acid used is preferably 70 mol% or more, more preferably 80 mol% or more, based on the total acid component. Examples of the ester-forming derivative of the dicarboxylic acid include lower dialkyl esters of aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and diphenylether-4,4'-dicarboxylic acid; lower dialkyl esters of alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and lower dialkyl esters of aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, and oxalic acid. One or more of these may be used, and they can be arbitrarily selected according to the purpose. When using two or more ester-forming derivatives of the dicarboxylic acid, the amount of the main component ester-forming derivative of the dicarboxylic acid used is preferably 70 mol% or more, more preferably 80 mol% or more, based on the total ester-forming derivative component of the dicarboxylic acid.

[0016] In addition, a trifunctional or higher-functional dicarboxylic acid component such as a small amount of trimellitic acid may be used, and a small amount of an acid anhydride such as trimellitic anhydride may also be used. Further, a small amount of a hydroxycarboxylic acid such as lactic acid or glycolic acid or its alkyl ester may be used, and it can be arbitrarily selected according to the purpose.

[0017] As the glycol component, for example, one or more alkylene glycols such as ethylene glycol, 1,4 - butanediol, 1,3 - propylene glycol, 1,2 - propylene glycol, neopentylene glycol, hexamethylene glycol, decamethylene glycol, cyclohexanedimethanol, diethylene glycol, triethylene glycol, poly(oxy)ethylene glycol, poly(oxy)tetramethylene glycol, poly(oxy)methylene glycol may be used, and it can be arbitrarily selected according to the purpose. Further, a small amount of a polyhydric alcohol component such as glycerin may be used. The amount of the glycol component as the main component is preferably 70 mol% or more, more preferably 80 mol% or more based on the total glycol components.

[0018] The amount of such glycol component used is preferably 1.1 to 1.4 times the molar amount of the dicarboxylic acid or the ester - forming derivative of the dicarboxylic acid. When the amount of the glycol component used is less than 1.1 times the molar amount, the esterification or transesterification reaction may not proceed sufficiently. Also, when it exceeds 1.4 times the molar amount, although the reason is not clear, the reaction rate becomes slow, and the amount of by - products such as tetrahydrofuran generated from the excess glycol component may increase.

[0019] In the production of a thermoplastic polyester resin, known polymerization catalysts can be used. Examples include titanium compounds, antimony compounds, germanium compounds, manganese compounds, aluminum compounds, etc. Among them, titanium compounds are preferred. As the titanium compound used as the polymerization catalyst, tetraalkyl titanate is preferred. Specifically, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-sec-butyl titanate, tetra-t-butyl titanate, tetra-n-hexyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, etc. can be mentioned, and these can also be used as mixed titanates. Among these titanium compounds, tetra-n-propyl titanate, tetraisopropyl titanate, and tetra-n-butyl titanate are particularly preferred, and tetra-n-butyl titanate is most preferred. The addition amount of the titanium compound is preferably 10 ppm or more and 60 ppm or less in terms of the titanium atom content in the produced thermoplastic polyester resin, and more preferably 15 ppm or more and 30 ppm or less. When the titanium atom content in the produced thermoplastic polyester resin exceeds 60 ppm, the color tone and thermal stability of the resin composition of the present invention may deteriorate. On the other hand, when the titanium atom content is less than 10 ppm, good polymerization activity cannot be obtained, and it may not be possible to obtain a thermoplastic polyester resin with a sufficiently high intrinsic viscosity. The thermoplastic polyester resin of the present invention is preferably produced via an esterification or transesterification reaction step of a dicarboxylic acid component mainly composed of a dicarboxylic acid and / or its ester-forming derivative and a glycol component in the presence of a polymerization catalyst, followed by a polycondensation reaction step. However, the temperature at the end of the esterification or transesterification reaction is preferably in the range of 180°C or more and 230°C or less, and more preferably 180°C or more and 220°C or less. When the temperature at the end of the esterification reaction or transesterification reaction exceeds 230°C, the reaction rate increases, but the amount of by-products such as tetrahydrofuran may increase. Also, when it is less than 180°C, the reaction may not proceed.The reaction product (bisglycol ether and / or its oligomer) obtained by the esterification or transesterification reaction is preferably polycondensed at a temperature between the melting point of the thermoplastic polyester resin and 290° C. under reduced pressure of 0.4 kPa (3 Torr) or less. If the polycondensation reaction temperature exceeds 290° C., the reaction rate may decrease and coloring may become significant.

[0020] Thermoplastic polyester resins may be used in one or more types, and can be selected arbitrarily depending on the purpose. When two or more types are used, the supply method is not particularly limited, but examples include a method in which pellet-shaped or powder-shaped thermoplastic polyester resins are mixed well in a blender in advance and then supplied to an extruder, and a method in which each is supplied independently. By using a thermoplastic polyester resin, it is possible to improve the long-term low wear and low friction coefficient of the molded body. Representative thermoplastic polyester resins include, for example, polybutylene naphthalate, polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, and copolymers thereof, and the above-mentioned dicarboxylic acid component and glycol component can be used as the copolymerization component, but polybutylene naphthalate resin, copolymers of polybutylene naphthalate resin, and mixtures of polybutylene naphthalate resin and other thermoplastic polyester resins are preferred, and polybutylene naphthalate resin is more preferred. By using these preferred thermoplastic polyester resins, the wear resistance may be further improved.

[0021] When a polybutylene naphthalate resin is used as component A of the present invention, the terminal carboxyl group concentration is 40 eq / 10 3 kg or less, and 30eq / 10 3 It is more preferable that the terminal carboxyl group concentration is 40 eq / 10 kg or less. 3 If it exceeds 1 kg, the retention stability of the melt viscosity may decrease.

[0022] <B成分について> The wollastonite used as component B of the present invention is not particularly limited as long as it is generally called wollastonite, and those known per se can be used. By using wollastonite as component B, abrasion resistance, high melt viscosity, and retention stability of the melt viscosity can be effectively imparted to the thermoplastic polyester resin composition.

[0023] Wollastonite is generally the name of a natural white mineral having acicular crystals mainly composed of calcium silicate, and is also called by the alias wollastonite. Its specific gravity is 2.80 to 2.95, and its melting point is 1400 to 1600 °C. Its chemical composition is substantially represented by the chemical formula CaSiO3, usually 47 to 52% by weight of SiO2 and 44 to 52% by weight of CaO, and contains other trace components such as Fe2O3, Al2O3, MgO, MnO, TiO2, K2O, and Na2O. Such purified, pulverized, and classified natural minerals can be preferably used, and artificially synthesized ones can also be used.

[0024] The shape of wollastonite is not particularly limited, but the average particle size measured by the laser diffraction scattering method defined in JIS Z8825-1 is preferably 0.5 to 15 μm, more preferably 1 to 10 μm. Examples of such suitable wollastonite include "SH-1250" and "SH-1800" manufactured by Kinsai Matec Co., Ltd., "KGP-H40" manufactured by Kansai Matec Co., Ltd., "NYGLOS4" manufactured by NYCO Co., Ltd., and the like.

[0025] In addition, wollastonite that has been surface-treated with a normal surface treatment agent, such as a coupling agent such as a silane-based coupling agent or a titanate-based coupling agent, may be used.

[0026] The content of component B is 10 to 70 parts by weight, preferably 15 to 65 parts by weight, more preferably 20 to 60 parts by weight, based on 100 parts by weight of component A. When the content is less than 10 parts by weight, the rigidity, abrasion resistance, melt viscosity, and retention stability of the melt viscosity decrease. When it exceeds 70 parts by weight, it becomes difficult to disperse the filler during kneading, and stable extrusion becomes difficult.

[0027] <Regarding Component C> The carbodiimide compound which is Component C of the present invention is a compound having one or more carbodiimide groups (-N = C = N-) in the molecule, and those known per se can be used. At least one carbodiimide compound selected from the group consisting of compounds having two or more carbodiimide groups is preferred, and at least one carbodiimide compound selected from the group consisting of compounds having two carbodiimide groups is more preferred. When having two carbodiimide groups, the melt viscosity may be increased by connecting polyester molecular chains to both ends of the carbodiimide group.

[0028] The 5% weight loss temperature of the carbodiimide compound is 370 °C or higher, preferably 380 °C or higher, more preferably 390 °C or higher. When the 5% weight loss temperature is less than 370 °C, the retention stability of the melt viscosity decreases. The reason for this is not clear, but it is presumed that the decomposition of the thermoplastic polyester resin is promoted by the decomposition products generated from the carbodiimide compound staying in the high temperature state or the radicals generated by the decomposition. The 5% weight loss temperature referred to here means the temperature at which the weight decreases by 5% based on the weight at the start of measurement when the temperature is raised from room temperature at a rate of 20 °C / min under nitrogen purge using a differential thermal balance (TGA). Although the upper limit of the 5% weight loss temperature is not particularly limited, it is preferably 500 °C. Specific examples of the carbodiimide compound having a 5% weight loss temperature of 370 °C or higher include cyclic carbodiimide compounds. In addition to the possibility of improving heat resistance due to being cyclic, the generation of isocyanate gas can be suppressed, and the working environment can be improved.

[0029] Examples of the cyclic carbodiimide compound include compounds represented by the following formula (1).

Chemical formula

Chemical formula

[0030] Examples of the alkyl group having 1 to 6 carbon atoms as the substituent include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

[0031] The cyclic carbodiimide compound has a cyclic structure. The cyclic structure has one carbodiimide group (-N = C = N-), and its first nitrogen and second nitrogen are bonded by a bonding group. One cyclic structure has only one carbodiimide group. The molecular weight of the cyclic carbodiimide compound is preferably 100 to 1,000. If the molecular weight is less than 100, there may be problems with the structural stability and volatility of the cyclic carbodiimide compound. Also, if the molecular weight is greater than 1,000, synthesis in a dilution system may be required in the production of cyclic carbodiimide, or the yield may decrease, which may cause problems in terms of cost. From this perspective, the molecular weight is more preferably 100 to 750, and even more preferably 250 to 750.

[0032] Specific examples of the cyclic carbodiimide compound include the following compounds including the compound represented by the above formula (1).

[0033]

Chemical formula

[0034]

Chemical formula

[0035]

Chemical formula

[0036] Moreover, these cyclic carbodiimide compounds can be produced by methods well-known in various documents and patent gazettes (for example, the method described in the pamphlet of International Publication WO10 / 071213).

[0037] The content of Component C is 0.05 to 2 parts by weight, preferably 0.05 to 1 part by weight, more preferably 0.1 to 0.6 part by weight, based on 100 parts by weight of Component A. When the content is less than 0.05 part by weight, the melt viscosity and the retention stability of the melt viscosity decrease. When it exceeds 2 parts by weight, coarse gel-like substances are generated during kneading, the strands are cleaved, and continuous extrusion becomes difficult.

[0038] <Regarding Component D> The present invention may contain a silane coupling agent having one or more functional groups reactive with a thermoplastic polyester resin in the molecule as Component D. By containing the above silane coupling agent, the rigidity, melt viscosity, and retention stability of the melt viscosity may be improved.

[0039] The silane coupling agent having one or more functional groups reactive with a thermoplastic polyester resin in the molecule in the present invention refers to a silane coupling agent having one or more functional groups capable of chemically reacting with the end groups of the thermoplastic polyester resin in the molecule. The functional group is not particularly limited as long as it is reactive with a carboxy group or a hydroxyl group which is an end group of the thermoplastic polyester resin. Examples thereof include an epoxy group, an amino group, an isocyanate group, a carboxylic anhydride group, a carbodiimide group, an oxazoline group, etc., and among them, an epoxy group is preferable.

[0040] Specific examples of the above silane coupling agent include epoxy group-containing alkoxysilane compounds such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane; amino group-containing alkoxysilane compounds such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane; isocyanate group-containing alkoxysilane compounds such as 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropylmethyldiethoxysilane, 3-isocyanatopropylethyldimethoxysilane, 3-isocyanatopropylethyldiethoxysilane, 3-isocyanatopropyltrichlorosilane, etc. Among them, epoxy group-containing alkoxysilane compounds are preferred.

[0041] The content of component D is preferably 0.01 to 2 parts by weight, more preferably 0.05 to 1.5 parts by weight, and still more preferably 0.1 to 1 part by weight, based on 100 parts by weight of component A. If the content is less than 0.01 part by weight, the melt viscosity and the retention stability of the melt viscosity may decrease. If it exceeds 2 parts by weight, the abrasion resistance may deteriorate.

[0042] <Regarding component E> The present invention may contain at least one phosphorus compound selected from the group consisting of phosphate esters and phosphonate esters as component E. By containing the above phosphorus compound, the catalytic activity in the thermoplastic polyester resin can be suppressed, and the melt viscosity and the retention stability of the melt viscosity may be improved.

[0043] Specific examples of the phosphorus compound include phosphate ester compounds such as trimethyl phosphate, triethyl phosphate, and triphenyl phosphate; phosphonate ester compounds such as dimethyl methylphosphonate, diethyl methylphosphonate, dimethyl ethylphosphonate, diethyl ethylphosphonate, dimethyl phenylphosphonate, diethyl phenylphosphonate, diphenyl phenylphosphonate, dimethyl benzylphosphonate, diethyl benzylphosphonate, diphenyl benzylphosphonate, lithium (ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate), sodium (ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate), magnesium bis(ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate), calcium bis(ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate), diethyl phosphonoacetic acid, methyl diethyl phosphonoacetate, and ethyl diethyl phosphonoacetate. Among them, trimethyl phosphate and ethyl diethyl phosphonoacetate are preferred.

[0044] The content of Component E is preferably 0.005 to 0.5 parts by weight, more preferably 0.01 to 0.3 parts by weight, and still more preferably 0.02 to 0.2 parts by weight, based on 100 parts by weight of Component A. If the content is less than 0.005 parts by weight, the melt viscosity and the retention stability of the melt viscosity may decrease; if it exceeds 0.5 parts by weight, the wear resistance may deteriorate.

[0045] <Other Components> The resin composition of the present invention may be blended with other thermoplastic resins within a range not contrary to the spirit of the present invention, and may contain various additives such as antioxidants, impact modifiers, plasticizers, organic and inorganic fillers other than Component B, flame retardants, colorants, light stabilizers, heat stabilizers other than Component E, antistatic agents, antiblocking agents, lubricants, dispersants, flow modifiers, and crystal nucleating agents, as necessary.

[0046] <Method for Producing Resin Composition> To produce the resin composition of the present invention, any method can be adopted. For example, a method of preliminarily mixing each component and optionally other components, then melt-kneading and pelletizing can be mentioned. As means for preliminary mixing, a Nauta mixer, V-type blender, Henschel mixer, mechanochemical apparatus, extrusion mixer, etc. can be mentioned. In preliminary mixing, granulation can also be carried out by an extrusion granulator or briquetting machine, etc. in some cases. After preliminary mixing, melt-kneading is carried out with a melt-kneading machine typified by a vented twin-screw extruder, and pelletizing is carried out with equipment such as a pelletizer. Other melt-kneading machines include a Banbury mixer, kneading rolls, a constant-temperature stirring vessel, etc., but a vented twin-screw extruder is preferred. Alternatively, a method can also be adopted in which each component and optionally other components are independently supplied to a melt-kneading machine typified by a twin-screw extruder without preliminary mixing.

[0047] <Regarding the molded article> The molded article obtained by using the resin composition of the present invention can be obtained by molding the pellets produced as described above. Preferably, it is obtained by injection molding or solidification extrusion molding. As injection molding, not only ordinary molding methods but also injection compression molding, injection press molding, gas-assisted injection molding, foam molding (including the method of injecting a supercritical fluid), insert molding, in-mold coating molding, heat-insulating mold molding, rapid heating and cooling mold molding, two-color molding, multi-color molding, sandwich molding, and ultra-high-speed injection molding, etc. can be mentioned. Also, either a cold runner system or a hot runner system can be selected for molding. As solidification extrusion molding, methods such as obtaining a molded article by solidification extrusion molding of a round bar and then cutting it into a disc shape, or obtaining a molded article by solidification extrusion molding of a thick sheet and then punching it into a predetermined shape can be mentioned.

Examples

[0048] Hereinafter, embodiments for carrying out the present invention will be described by way of examples, but the present invention is not limited thereto. Also, the evaluation of various physical properties was carried out by the following methods.

[0049] [Evaluation of Resin Composition] (1) Rigidity Using the pellets obtained by the following method, the flexural modulus was measured in accordance with JIS K 7171. The test was conducted three times, and the average value thereof was used as an index of the rigidity of the composition. It is necessary that the rigidity be 4 GPa or more. (2) Abrasion Resistance After drying the pellets obtained by the following method at 120 °C for 6 hours, injection molding was performed using an injection molding machine (EC130SXII-4Y manufactured by Toshiba Machine Co., Ltd.) under the conditions of a cylinder temperature of 280 °C and a mold temperature of 120 °C to obtain a plate-shaped test piece with a thickness of 2 mm, a width of 50 mm, and a length of 50 mm. Using this test piece, a sliding test was conducted using a reciprocating friction tester (Tribogear TYPE-40, manufactured by Shinto Kagaku Co., Ltd.) under the conditions of a surface pressure of 140 MPa, a speed of 100 mm / s, and 7,000 reciprocations, with a SUJ2 metal ball with a diameter of 3 mm as the indenter. For the sliding surface after the test, a cross-sectional curve was measured in a direction perpendicular to the sliding direction using a surface roughness shape measuring machine (SURFCOM NEX001 SD2-12, manufactured by Tokyo Seimitsu Co., Ltd.) to obtain the depth of wear by the sliding test. The test was conducted three times, and the average value thereof was used as an index of the abrasion resistance of the composition. It is necessary that the wear depth be 3 μm or less. (3) Melt Viscosity Using the pellets obtained by the following method, the melt volume flow rate (MVR) at 280 °C and 2.16 kg was measured in accordance with JIS K 7210. At this time, the preheating time after filling the sample was 4 minutes. The test was conducted three times, and the average value thereof was used as an index of the melt viscosity of the composition. Note that MVR refers to the amount of resin extruded in 10 minutes under predetermined conditions, and the smaller the value of MVR, the higher the melt viscosity. The MVR is 7 cm 3 / 10 min or less is necessary. (4) Residence Stability of Melt Viscosity Using the pellets obtained by the following method, the melt volume flow rate (MVR) at 280 °C and 2.16 kg was measured in accordance with JIS K 7210. At this time, the preheating time after filling the sample was 14 minutes. The test was conducted three times, and the average value thereof was used as an index of the residence stability of the melt viscosity of the composition. The MVR is 15 cm3 It is necessary to be less than 10 min.

[0050] [Examples 1-11, Comparative Examples 1-6] According to the addition amounts shown in Table 1, Component A, Component C, Component D, and Component E were separately supplied to a twin-screw extruder from the first supply port. Here, the first supply port refers to the supply port at the base. Component B was separately supplied using a side feeder from the second supply port. Extrusion was carried out using a vented twin-screw extruder with a diameter of 30 mm Φ (manufactured by Japan Steel Works, Ltd.: TEX30α-31.5BW-2V), at a discharge rate of 20 kg / h, an extrusion temperature of 280 °C, and a vacuum degree of 3 kPa at the vent to obtain pellets. In Comparative Example 2, undispersed Component B scattered from the vent port during kneading, resulting in frequent strand breakage and inability to obtain pellets. Also, in Comparative Example 4, large gel-like substances were generated during kneading, causing strand cracking and the screw torque exceeding the upper limit, so pellets could not be obtained.

[0051] The above evaluation was carried out using the pellets. The results are shown in Table 1.

[0052] (Component A) A-1: Polybutylene naphthalate resin obtained in Production Example I <Production Example I> 315.0 parts of dimethyl 2,6-naphthalenedicarboxylate, 200.0 parts of 1,4-butanediol, and 0.062 part of tetra-n-butyl titanate were placed in a transesterification reaction vessel, and the transesterification reaction was carried out for 150 minutes while raising the temperature so that the transesterification reaction vessel reached 210°C. Subsequently, the obtained reaction product was transferred to a polycondensation reaction vessel to initiate the polycondensation reaction. The polycondensation reaction gradually reduced the pressure inside the polycondensation reaction layer from normal pressure to 0.13 kPa (1 torr) or less over 40 minutes, and at the same time, the temperature was raised to a predetermined reaction temperature of 260°C. Thereafter, the polycondensation reaction was carried out for 140 minutes while maintaining the polycondensation reaction temperature at 260°C and the pressure at 0.13 kPa (1 torr). When 140 minutes had elapsed, the polycondensation reaction was terminated, and the polybutylene naphthalate resin was extruded in a strand shape and cut into chips using a cutter while being water-cooled. Next, the obtained polybutylene naphthalate resin was subjected to solid-phase polymerization for 8 hours under the conditions of a temperature of 213°C and a pressure of 0.13 kPa (1 Torr) or less, and a polybutylene naphthalate resin having a terminal carboxy group concentration of 30 eq / 10 3 kg was obtained. A-2: Polybutylene naphthalate resin obtained in Production Example II <Production Example II> A polymerization reaction was carried out in the same manner as in Production Example I except that the addition amount of tetra-n-butyl titanate was 0.083 part, and a polybutylene naphthalate resin having a terminal carboxy group concentration of 41 eq / 10 3 kg was obtained.

[0053] (Component B) B-1: Wollastonite (manufactured by Kansai Mateck Co., Ltd., KGP-H40 (product name), average particle diameter 4 μm) B-2 (Comparative Example): Talc (manufactured by Shoko Yamakyo Co., Ltd., Victolite TK-RC (product name), average particle diameter 5 μm)

[0054] (Component C) C-1: Cyclic carbodiimide compound obtained in Production Example III In addition, each value in the production examples was determined by the following method. (1) Identification of cyclic carbodiimide structure by NMR Identification by NMR was performed using JNREX270 manufactured by JEOL Ltd., 1 1H-NMR, 13 and confirmed by 13C-NMR. Chloroform-d was used as the solvent. (2) Identification of the carbodiimide skeleton by IR Identification of the carbodiimide skeleton was performed using Magna-750 manufactured by Nicolet Corporation, and the absorption peak at 2100 - 2200 cm -1 characteristic of carbodiimide was confirmed by FT-IR. (3) Measurement of the 5% weight loss temperature of the carbodiimide compound Using TG8121 manufactured by Rigaku, 5 - 10 mg of the carbodiimide compound was heated from room temperature at a rate of 20 °C / min under nitrogen purge, and the temperature at which the weight decreased by 5% based on the weight at the start of the measurement was determined. <Production Example III> o-Nitrophenol (0.11 mol), pentaerythritol tetrabromide (0.025 mol), potassium carbonate (0.33 mol), and 200 ml of N,N-dimethylformamide were charged into a reaction apparatus equipped with a stirrer and a heating device under a nitrogen atmosphere. After reacting at 130 °C for 12 hours, DMF was removed under reduced pressure. The resulting solid was dissolved in 200 ml of dichloromethane, and liquid separation was performed three times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and dichloromethane was removed under reduced pressure to obtain intermediate product F (nitro form). Next, intermediate product F (0.1 mol), 5% palladium on carbon (Pd / C) (2 g), and 400 ml of ethanol / dichloromethane (70 / 30) were charged into a reaction apparatus equipped with a stirrer. Hydrogen substitution was performed five times, and the reaction was carried out at 25 °C with a continuous supply of hydrogen. The reaction was terminated when the decrease in hydrogen ceased. Pd / C was recovered, and the mixed solvent was removed to obtain intermediate product G (amine form). Next, into a reaction apparatus equipped with a stirrer, a heating device, and a dropping funnel, triphenylphosphine dibromide (0.11 mol) and 150 ml of 1,2-dichloroethane were charged and stirred under a nitrogen atmosphere. A solution prepared by dissolving intermediate product G (0.025 mol) and triethylamine (0.25 mol) in 50 ml of 1,2-dichloroethane was gradually added dropwise thereto at 25 °C. After the addition was completed, the reaction was carried out at 70 °C for 5 hours. Thereafter, the reaction solution was filtered, and the filtrate was subjected to liquid separation five times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and 1,2-dichloroethane was removed under reduced pressure to obtain intermediate product H (triphenylphosphine form). Next, into a reaction apparatus equipped with a stirrer and a dropping funnel, di-tert-butyl dicarbonate (0.11 mol), N,N-dimethyl-4-aminopyridine (0.055 mol), and 150 ml of dichloromethane were charged and stirred under a nitrogen atmosphere. 100 ml of dichloromethane in which intermediate product H (0.025 mol) was dissolved at 25 °C was slowly added dropwise thereto. After the addition, the reaction was carried out for 12 hours. Thereafter, dichloromethane was removed, and the resulting solid was purified to obtain component C-1 represented by the following formula. The structure of component C-1 was confirmed by NMR and IR. The 5% weight loss temperature of component C-1 was 415 °C.

[0055] [Chemical formula]

[0056] C-2 (Comparative Example): Aliphatic polycarbodiimide compound (manufactured by Nisshinbo Industries, Inc., Carbodilite HMV-8CA (product name), 5% weight loss temperature 320 °C)

[0057] (Component D) D-1: Epoxy group-containing alkoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403 (product name), 3-glycidoxypropyltrimethoxysilane)

[0058] (Component E) E-I: Phosphonate ester (manufactured by Johoku Chemical Industry Co., Ltd., JC-224 (product name), ethyl diethylphosphonoacetate)

[0059] (Other components) F-1: Silane coupling agent having no functional group reactive with thermoplastic polyester resin (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-3103 (product name), decyltrimethoxysilane)

[0060]

Table 1

[0061] <Examples 1 to 11> Since it is a resin composition within the scope of the claims, it had a high melt viscosity and excellent wear resistance, rigidity, and retention stability of melt viscosity. <Comparative Example 1> Since the content of Component B was less than the lower limit, the results were inferior in terms of rigidity, wear resistance, melt viscosity, and retention stability of melt viscosity. <Comparative Example 2> Since the content of Component B exceeded the upper limit, undispersed Component B scattered from the vent port during kneading, and strand breakage occurred frequently, making it impossible to obtain pellets. <Comparative Example 3> Since the content of Component C was less than the lower limit, the melt viscosity and the retention stability of the melt viscosity were poor. <Comparative Example 4> Since the content of Component C exceeded the upper limit, coarse gel-like substances were generated during kneading, the strands were cleaved, and the torque of the screw exceeded the upper value, so pellets could not be obtained. <Comparative Example 5> Since the 5% weight loss temperature of Component C was less than the lower limit, the retention stability of the melt viscosity was poor. <Comparative Example 6> Since Component B was other than wollastonite, the abrasion resistance, the melt viscosity, and the retention stability of the melt viscosity were poor.

Claims

1. (A) A polyester resin composition containing 10 to 70 parts by weight of wollastonite (Component B) and 0.05 to 2 parts by weight of a carbodiimide compound (Component C) having a 5% weight loss temperature of 370°C or higher with respect to 100 parts by weight of a thermoplastic polyester resin (Component A).

2. The resin composition according to Claim 1, containing 0.01 to 2 parts by weight of a silane coupling agent (Component D) having one or more functional groups reactive with a thermoplastic polyester resin in the molecule with respect to 100 parts by weight of Component A.

3. The resin composition according to Claim 2, wherein Component D is a silane coupling agent having an epoxy group.

4. The resin composition according to Claim 1 or 2, wherein Component C is a cyclic carbodiimide compound represented by the following formula (1). 【Chemical 1】 In formula (1), X is a tetravalent group represented by the following formula (2), and Ar １ ~Ar ４ each independently represents an o-phenylene group or a 1,2-naphthalene-diyl group, which may be substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group. [Chemical 2]

5. Component A is a polybutylene naphthalate resin having a terminal carboxy group concentration of 40 eq / 10 ３ kg or less, and the resin composition according to claim 1 or 3

6. The resin composition according to Claim 1 or 3, containing 0.005 to 0.5 parts by weight of at least one phosphorus compound (Component E) selected from the group consisting of phosphate esters and phosphonate esters with respect to 100 parts by weight of Component A.

7. The resin composition according to Claim 1 or 3, which is used for solidification extrusion molding.

8. A molded article formed by molding the resin composition according to Claim 1 or 3.

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