JP2013194176A - Thermoplastic polyester resin composition for epicyclic gear, and epicyclic gear using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic polyester resin for epicyclic gear, which has a combination of excellent slidability, fatigue characteristics, impact resistance and heat resistance, and an epicyclic gear using the same.SOLUTION: This thermoplastic polyester resin for epicyclic gear contains, relative to 100 pts. wt of a thermoplastic polyester resin composed of (A) 50-95 pts.wt. of a polybutylene naphthalate resin (component A) and (B) 50-5 pts.wt. of a polybutylene terephthalate resin having terminal carboxy group concentration of 18 eq/ton or less and inherent viscosity of 0.7-1.1 dL/g, (C) 0.001-5 pts.wt. of at least one antioxidant (component C) selected from the group consisting of phosphite-based compounds, phosphate-based compounds, phosphonite-based compounds and hindered phenol-based compounds; and (D) 1-10 pts.wt. of an impact modifier (component D).

Description

  The present invention relates to a thermoplastic polyester resin composition for planetary gears and a planetary gear using the same. More specifically, by blending polybutylene terephthalate resin, antioxidant, impact modifier, etc. with polybutylene naphthalate resin, a planet that has excellent slidability, fatigue characteristics, impact resistance, and heat resistance. The present invention relates to a thermoplastic polyester resin composition for gears and a planetary gear using the same.

  Conventionally, resin gears have been used in a wide range of fields such as home appliance parts, OA parts, and automobile parts because they are excellent in lightness, self-lubrication, low noise, corrosion resistance, and mass productivity. As the resin used for the gear, there are various types such as polybutylene terephthalate resin (PBT resin), polyacetal resin (POM resin), polyamide resin (PA resin) and the like. In recent years, gear mechanisms have become highly functional and complex, and one of them is a planetary gear mechanism that has a sun gear at the center, a planetary gear around it, and an internal gear around the planetary gear. Due to problems with dimensional stability, fatigue characteristics, and slidability, polybutylene terephthalate resin is often used for sun gears, polyacetal resin is used for internal gears, and vice versa, and planetary gears rotate and revolve around sun gears. There are many cases. Therefore, a planetary gear is required to have a resin that has good slidability, fatigue characteristics, impact resistance, and heat resistance with respect to both polybutylene terephthalate resin and polyacetal resin.

  As a method for improving the slidability of the thermoplastic resin, a method of adding a silicone oil, rubber, polymer or the like is known. For example, a composition in which silicone oil and silicone graft polyester are added to a synthetic resin has been proposed. (Refer patent document 1) Moreover, the composition which added the composite rubber-type graft copolymer which consists of a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate component to the thermoplastic resin is proposed. (Refer patent document 2) Moreover, the composition which added the modified silicone elastomer to the polyester-type thermoplastic elastomer is proposed. However, these silicone-based resin compositions may cause contact defects such as relays and switches of electrical / electronic equipment components due to volatilization of low-molecular siloxane during use. Moreover, there is no description regarding fatigue characteristics, and it cannot be said that the resin composition can satisfy the characteristics of the planetary gear.

  Also, hydrocarbons such as liquid paraffin and polyethylene wax, higher fatty acids, oxy fatty acids, fatty acid amides, esters of fatty acids and alcohols, fatty acids such as metal soaps using fatty acids as raw materials, alcohols such as polyglycols and polyhydric alcohols A method for improving the slidability by adding a lubricant such as a system is known. For example, a composition obtained by blending a higher alcohol fatty acid ester and a fatty acid metal salt with a thermoplastic polyester resin has been proposed. (Refer patent document 4) Moreover, the composition which consists of a high-density polyethylene resin and an acid-modified polyethylene resin in polybutylene naphthalate resin is proposed. However, these compositions have insufficient improvement in slidability, and a large amount of addition is required to improve sufficient slidability, resulting in mold deposits and peeling problems. It is easy to produce. Moreover, there is no description regarding fatigue characteristics, and it cannot be said that the resin composition can satisfy the characteristics of the planetary gear.

  As a method for improving the fatigue characteristics of a thermoplastic resin, for example, a composition in which a layered silicate is blended with a thermoplastic polyester has been proposed. (Refer patent document 6) Moreover, the composition which mix | blended liquid crystalline resin with the thermoplastic resin is proposed. Although these resin compositions are excellent in fatigue characteristics, there is no description regarding slidability, and it cannot be said that these resin compositions can satisfy the characteristics of a planetary gear.

As a method for improving the impact resistance of a thermoplastic resin, for example, a composition in which a saturated polyester resin is blended with rubber-reinforced styrene and dipentaerythritol fatty acid ester has been proposed. (Refer to patent document 8) Although this resin composition is excellent in impact resistance, there is no description regarding slidability and fatigue characteristics, and it cannot be said that the resin composition can satisfy the characteristics of the planetary gear.
As described above, there is no resin composition suitable for a planetary gear, and a resin composition having excellent slidability, fatigue characteristics, impact resistance, and heat resistance is desired.

JP-A-8-3454 Japanese Patent Laid-Open No. 10-237266 JP-A-8-283552 Japanese Patent Laid-Open No. 11-71506 JP 2010-1111759 A JP 2000-212294 A JP 2001-192518 A Japanese Patent No. 3575152

  An object of the present invention is to provide a thermoplastic polyester resin composition for a planetary gear having excellent slidability, fatigue characteristics, impact resistance, and heat resistance necessary for the planetary gear.

  As a result of repeated studies on good slidability, fatigue properties, impact resistance, and heat resistance for both polybutylene terephthalate resins and polyacetal resins, the present inventors have determined that specific terminal carboxyls in polybutylene naphthalate resins. By blending a polybutylene terephthalate resin having a base concentration and an intrinsic viscosity, a specific antioxidant, and an impact modifier, good slidability, fatigue properties, resistance to both polybutylene terephthalate resin and polyacetal resin The present inventors have found that it has both impact resistance and heat resistance, and have reached the present invention.

According to the present invention, (1) (A) polybutylene naphthalate resin (component A) 50 to 95 parts by weight and (B) the terminal carboxyl group concentration is 18 eq / ton or less, and the intrinsic viscosity is 0.7 to (C) Phosphite compound, phosphate compound, phosphonite compound and hindert with respect to 100 parts by weight of thermoplastic polyester resin comprising 50 to 5 parts by weight of polybutylene terephthalate resin (component B) of 1.1 dl / g For planetary gears containing 0.001 to 5 parts by weight of at least one antioxidant (C component) selected from the group consisting of phenolic compounds and (D) impact modifier (D component) 1 to 10 parts by weight A thermoplastic polyester resin composition is provided.
One of the preferred embodiments of the present invention is (1) wherein the D component is selected from the group consisting of an aromatic vinyl monomer, a vinyl cyanide monomer, and an alkyl (meth) acrylate monomer as a rubber component. It is a thermoplastic polyester resin composition for planetary gears of the above constitution (1), characterized in that it is a rubber-modified polymer obtained by polymerizing more than one species.
One of the preferred embodiments of the present invention is a planetary gear comprising (3) the thermoplastic polyester resin composition for planetary gears of the above constitution (1) or (2).

Hereinafter, the details of the present invention will be described.
(Component A: polybutylene naphthalate resin)
The polybutylene naphthalate resin (hereinafter may be abbreviated as “PBN”), which is the component A of the present invention, comprises a dicarboxylic acid component mainly composed of naphthalene dicarboxylic acid and / or an ester-forming derivative of naphthalene dicarboxylic acid, and 1 , 4-butanediol can be used as a main component.

  As the naphthalenedicarboxylic acid component, 2,6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid are the main components, but other dicarboxylic acids can be used in combination as long as the characteristics are not impaired. Examples of other carboxylic acids include terephthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, diphenoxyethane-4,4′-dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid, diphenyl ether-4, Aromatic dicarboxylic acids such as 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, etc. Two or more kinds may be used and can be arbitrarily selected according to the purpose. The amount of other carboxylic acid used is preferably 30 mol% or less, more preferably 20 mol% or less, based on the total acid component. As ester-forming derivatives of naphthalenedicarboxylic acid, dimethyl 2,6-naphthalenedicarboxylate and dimethyl 2,7-naphthalenedicarboxylate are the main components, but other dicarboxylic acid esters as long as the characteristics are not impaired. Formable derivatives can be used in combination. Examples of ester-forming derivatives of other dicarboxylic acids include terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid. Acids, lower dialkyl esters of aromatic dicarboxylic acids such as diphenyl ether-4,4'-dicarboxylic acid, lower dialkyl esters of alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, adipic acid, sebacic acid, succinic acid, oxalic acid, etc. The lower dialkyl ester of aliphatic dicarboxylic acid etc. are mentioned, These 1 type (s) or 2 or more types may be used, and it can select arbitrarily according to the objective. The amount of other dicarboxylic acid ester-forming derivatives used is preferably 30 mol% or less, more preferably 20 mol% or less, based on the total dicarboxylic acid ester-forming derivative component.

  Further, a tri- or higher functional carboxylic 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 be used. Further, a small amount of hydroxycarboxylic acid such as lactic acid or glycolic acid or an alkyl ester thereof may be used and can be arbitrarily selected depending on the purpose.

  Although 1,4-butanediol is the main component of the glycol component, other glycol components can be used in combination as long as the characteristics are not impaired. Examples of other glycol components include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, neopentylene glycol, hexamethylene glycol, decamethylene glycol, cyclohexane dimethanol, diethylene glycol, triethylene glycol, polyethylene glycol, One or more alkylene glycols such as (oxy) ethylene glycol, poly (oxy) tetramethylene glycol and poly (oxy) methylene glycol may be used, and can be arbitrarily selected according to the purpose. Furthermore, a small amount of a polyhydric alcohol component such as glycerin may be used. A small amount of an epoxy compound may be used. The amount of other glycol components used is preferably 30 mol% or less, more preferably 20 mol% or less, based on the total glycol components.

  The amount of the glycol component used is preferably 1.1 mol times or more and 1.4 mol times or less with respect to the dicarboxylic acid or the ester-forming derivative of dicarboxylic acid. When the amount of the glycol component used is less than 1.1 mole times, the esterification or transesterification reaction does not proceed sufficiently, which is not preferable. Further, when the amount exceeds 1.4 mol times, the reason is not clear, but the reaction rate becomes slow, and the amount of by-products such as tetrahydrofuran from the excessive glycol component increases, which is not preferable.

  In the production of PBN, a titanium compound is used as a polymerization catalyst. As a titanium compound used as a polymerization catalyst, tetraalkyl titanate is preferable, and 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 and the like may be mentioned, and these may be used as mixed titanates. Among these titanium compounds, tetra-n-propyl titanate, tetraisopropyl titanate, and tetra-n-butyl titanate are particularly preferable, and tetra-n-butyl titanate is most preferable. The addition amount of the titanium compound is preferably 10 ppm or more and 60 ppm or less, more preferably 15 ppm or more and 30 ppm or less as the titanium atom content in the produced PBN. When the titanium atom content in the produced PBN exceeds 60 ppm, the color tone and thermal stability of the thermoplastic polyester resin composition of the present invention are not preferred. On the other hand, when the titanium atom content is less than 10 ppm, good polymerization activity cannot be obtained, and a sufficiently high intrinsic viscosity PBN cannot be obtained. The PBN of the present invention is obtained by esterifying or esterifying a dicarboxylic acid component mainly composed of naphthalenedicarboxylic acid and / or an ester-forming derivative thereof and a glycol component mainly composed of 1,4-butanediol in the presence of a titanium compound. It is preferably produced via an exchange reaction step and a subsequent polycondensation reaction step, but the temperature at the end of esterification or transesterification reaction is preferably in the range of 180 ° C. or more and 220 ° C. or less, More preferably, it is 180 ° C. or higher and 210 ° C. or lower. When the temperature at the end of the esterification reaction or transesterification reaction exceeds 220 ° C., the reaction rate increases, but it is not preferable because by-products such as tetrahydrofuran increase. On the other hand, if the temperature is less than 180 ° C., the reaction does not proceed. The reaction product (bisglycol ether and / or its low polymer) obtained by esterification or transesterification is reduced to 0.4 kPa (3 Torr) or less at a temperature not lower than the melting point of PBN and not higher than 270 ° C. Preference is given to polycondensation below. If the polycondensation reaction temperature exceeds 270 ° C., the reaction rate is rather lowered, and coloring is increased, which is not preferable.

  The content of PBN is 50 to 95 parts by weight, preferably 55 to 90 parts by weight, more preferably 100 parts by weight in total of 100 parts by weight of PBN and polybutylene terephthalate (hereinafter sometimes abbreviated as “PBT”). 60 to 85 parts by weight. When the content is less than 50 parts by weight, the slidability is lowered, and when it exceeds 95 parts by weight, the heat resistance is undesirably lowered.

(B component: polybutylene terephthalate resin)
The polybutylene terephthalate resin as component B of the present invention is a resin obtained by polycondensation reaction from terephthalic acid or a derivative thereof and 1,4-butanediol or a derivative thereof, but does not impair the purpose of the present invention. It is possible to copolymerize other dicarboxylic acids and glycols.

  Examples of copolymerizable dicarboxylic acids include isophthalic acid, 2-chloroterephthalic acid, 2,5-dichloroterephthalic acid, 2-methylterephthalic acid, 4,4-stilbene dicarboxylic acid, 4,4-biphenyldicarboxylic acid, and orthophthalic acid. Aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, bisbenzoic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4-diphenyl ether dicarboxylic acid, 4,4-diphenoxyethanedicarboxylic acid, Mention may be made of aliphatic and alicyclic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid. These copolymerizable dicarboxylic acids can be used alone or in admixture of two or more.

  Examples of copolymerizable glycols include 1,2-propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, trans- or cis-2,2,4,4-tetramethyl. -1,3-cyclobutanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, decamethylene glycol, cyclohexanediol, p -Xylene diol, bisphenol A, etc. can be mentioned. If the amount is even smaller, one or more long-chain diols having a molecular weight of 400 to 6,000, that is, polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, and the like may be copolymerized. These copolymerizable glycols can be used alone or in combination of two or more.

  The PBT of the present invention can be branched by introducing a small amount of a branching agent. Although there is no restriction | limiting in the kind of branching agent, A trimesic acid, a trimellitic acid, a trimethylol ethane, a trimethylol propane, a pentaerythritol, etc. are mentioned.

  About the manufacturing method of PBT of this invention, according to a conventional method, the dicarboxylic acid component and the said diol component are superposed | polymerized in the presence of the polycondensation catalyst containing titanium, germanium, antimony, etc., and water byproduced. Alternatively, the lower alcohol is discharged out of the system. For example, germanium-based polymerization catalysts include germanium oxides, hydroxides, halides, alcoholates, phenolates, and the like. More specifically, germanium oxide, germanium hydroxide, germanium tetrachloride, tetramethoxygermanium, etc. Can be illustrated.

  Further, in the present invention, compounds such as manganese, zinc, calcium, magnesium, etc., which are used in a transesterification reaction that is a prior stage of a conventionally known polycondensation, can be used in combination, and phosphoric acid or phosphorous after completion of the transesterification reaction. Such a catalyst can be deactivated and polycondensed with an acid compound or the like.

The terminal group structure of the obtained PBT has a terminal carboxyl group concentration in the range of 18 eq / ton or less, more preferably 16 eq / ton or less, and further preferably 14 eq / ton or less. The smaller the terminal carboxyl group concentration, the better the thermal stability of the polyester resin and the better the impact resistance. In addition to the case where the ratio of the hydroxyl group and the carboxyl group in the terminal group is substantially the same, it may be the case where the ratio of one is large. Moreover, those terminal groups may be sealed by reacting a compound having reactivity with such terminal groups. The terminal carboxyl group concentration was obtained by dissolving 0.4 g of resin in 100 ml of benzyl alcohol at room temperature, and titrating the obtained resin solution with 0.1 N NaOH using an automatic titrator GT-100 (manufactured by Mitsubishi Chemical). Value, equivalent concentration of terminal carboxyl groups per 1 × 10 ⁶ g.

  The intrinsic viscosity (IV) of PBT is in the range of 0.7 to 1.1 dl / g, more preferably 0.75 to 1.05 dl / g, and still more preferably 0.8 to 1.0 dl / g. When the intrinsic viscosity is less than 0.7 dl / g, the impact resistance is lowered, and when it exceeds 1.05 dl / g, the heat resistance is lowered. Intrinsic viscosity is obtained by dissolving 0.6 g of resin in 50 ml of orthochlorophenol by heating and then cooling to room temperature, and measuring the viscosity of the resulting resin solution at 35 ° C. using an Ostwald type viscosity tube. The intrinsic viscosity (IV) of the resin is calculated from the obtained solution viscosity data.

  The content of PBT is 5 to 50 parts by weight, preferably 10 to 45 parts by weight, more preferably 15 to 40 parts by weight, in a total of 100 parts by weight of PBN and PBT. When the content is less than 5 parts by weight, the heat resistance decreases, and when it exceeds 50 parts by weight, the slidability decreases, which is not preferable.

(C component: antioxidant)
The antioxidant used as the component C in the present invention is at least one antioxidant selected from the group consisting of phosphite compounds, phosphate compounds, phosphonite compounds and hindered phenol compounds.

  Examples of such phosphite compounds include triphenyl phosphite, tris (nonylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite. , Diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, tris (diethylphenyl) ) Phosphite, Tris (di-iso-propylphenyl) phosphite, Tris (di-n-butylphenyl) phosphite, Tris (2,4-di-tert-butylphenyl) Phosphite, tris (2,6-di-tert-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-ethylphenyl) pentaerythritol diphosphite, bis {2,4-bis ( 1-methyl-1-phenylethyl) phenyl} pentaerythritol diphosphite, phenylbisphenol A pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, dicyclohexyl pentaerythritol diphosphite, etc. It is below. Further, as other phosphite compounds, those which react with dihydric phenols and have a cyclic structure can be used. For example, 2,2′-methylenebis (4,6-di-tert-butylphenyl) (2,4-di-tert-butylphenyl) phosphite, 2,2′-methylenebis (4,6-di-tert- Examples include butylphenyl) (2-tert-butyl-4-methylphenyl) phosphite, 2,2′-methylenebis (4-methyl-6-tert-butylphenyl) octyl phosphite, and the like.

  Examples of such phosphate compounds include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorthoxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl Examples thereof include phosphate and diisopropyl phosphate, and triphenyl phosphate and trimethyl phosphate are preferable.

  Examples of such phosphonite compounds include tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,3′-. Biphenylene diphosphonite, tetrakis (2,4-di-tert-butylphenyl) -3,3'-biphenylenediphosphonite, tetrakis (2,6-di-tert-butylphenyl) -4,4'-biphenylenedi Phosphonite, tetrakis (2,6-di-tert-butylphenyl) -4,3′-biphenylene diphosphonite, tetrakis (2,6-di-tert-butylphenyl) -3,3′-biphenylene diphosphonite Bis (2,4-di-tert-butylphenyl) -4-phenyl-phenylphosphonite, bis (2 4-di-tert-butylphenyl) -3-phenyl-phenylphosphonite, bis (2,6-di-n-butylphenyl) -3-phenyl-phenylphosphonite, bis (2,6-di-tert- Butylphenyl) -4-phenyl-phenylphosphonite, bis (2,6-di-tert-butylphenyl) -3-phenyl-phenylphosphonite, and the like, and tetrakis (di-tert-butylphenyl) -biphenyl Range phosphonite, bis (di-tert-butylphenyl) -phenyl-phenylphosphonite are preferred, tetrakis (2,4-di-tert-butylphenyl) -biphenylenediphosphonite, and bis (2,4-di-) Tert-butylphenyl) -phenyl-phenylphosphonite is more preferred. Such a phosphonite compound is preferable because it can be used in combination with a phosphite compound having an aryl group in which two or more alkyl groups are substituted.

  Examples of such hindered phenol compounds include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2- tert-Butyl-6- (3′-tert-butyl-5′-methyl-2′-hydroxybenzyl) -4-methylphenyl acrylate, 2,6-di-tert-butyl-4- (N, N-dimethyl) Aminomethyl) phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4- Ethyl-6-tert-butylphenol), 4,4'-methylenebi (2,6-di-tert-butylphenol), 2,2′-methylenebis (4-methyl-6-cyclohexylphenol), 2,2′-dimethylene-bis (6-α-methyl-benzyl-p-cresol) 2,2′-ethylidene-bis (4,6-di-tert-butylphenol), 2,2′-butylidene-bis (4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl) -6-tert-butylphenol), triethylene glycol-N-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, 1,6-hexanediol bis [3- (3 5-di-tert-butyl-4-hydroxyphenyl) propionate], bis [2-tert-butyl-4-methyl 6- (3 tert-butyl-5-methyl-2-hydroxybenzyl) phenyl] terephthalate, 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1, 1, -dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane, 4,4′-thiobis (6-tert-butyl-m-cresol), 4,4′-thiobis ( 3-methyl-6-tert-butylphenol), 2,2′-thiobis (4-methyl-6-tert-butylphenol), bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 4, 4′-di-thiobis (2,6-di-tert-butylphenol), 4,4′-tri-thiobis (2,6-di-tert-butylphenol) ), 2,2-thiodiethylenebis- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis (n-octylthio) -6- (4-hydroxy-) 3,5-di-tert-butylanilino) -1,3,5-triazine, N, N′-hexamethylenebis- (3,5-di-tert-butyl-4-hydroxyhydrocinnamide), N, N '-Bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-tert-butyl-4- Hydroxyphenyl) isocyanurate, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) ) Isocyanurate, 1,3,5-tris 2 [3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl isocyanurate, and tetrakis [methylene-3- (3,5-di -Tert-butyl-4-hydroxyphenyl) propionate] methane and the like. Among these, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (CIBA SPECILITY CHEMICALS: Irganox 1076 (trade name)) is preferable as a typical commercial product.

All of the above antioxidants are easily available, and these can be used alone or in combination of two or more.
The content of the antioxidant (component C) is 0.001 to 5 parts by weight, preferably 0.003 to 3 parts by weight, based on 100 parts by weight of the thermoplastic polyester resin composed of PBT and PBN. Preferably it is 0.005-1 weight part. If the content is less than 0.001 part by weight, there is no effect of improving the thermal stability, and if it exceeds 5 parts by weight, the thermal stability is deteriorated. Needless to say, when the thermal stability is deteriorated, the impact resistance is lowered and the gear is easily damaged.

(D component: impact modifier)
The impact modifier as component D of the present invention is preferably at least one selected from the group consisting of a rubber-modified polymer, a reactive olefin copolymer, and a mixture thereof. It is particularly preferred.
The rubber-modified polymer is obtained by polymerizing a rubber component with at least one selected from the group consisting of an aromatic vinyl monomer, a vinyl cyanide monomer, and an alkyl (meth) acrylate monomer. It is a polymer.

  The rubber component is a polymer having rubber elasticity which becomes a base of a rubbery polymer. Examples of such rubber components include polybutadiene, polyisoprene, and diene copolymers (for example, random and block copolymers of styrene / butadiene, acrylonitrile / butadiene copolymers, and acrylic / butadiene rubbers (alkyl acrylates). Ester or methacrylic acid alkyl ester and butadiene copolymer), copolymers of ethylene and α-olefin (eg, ethylene / propylene random copolymers and block copolymers, ethylene / butene random copolymers). And block copolymers), copolymers of ethylene and unsaturated carboxylic acid esters (such as ethylene / methacrylate copolymers and ethylene / butyl acrylate copolymers), copolymers of ethylene and aliphatic vinyl (For example, Ethylene / vinyl acetate copolymer), ethylene / propylene and non-conjugated diene terpolymer (eg, ethylene / propylene / hexadiene copolymer), acrylic rubber (eg, polybutyl acrylate, poly (2-ethylhexyl acrylate), And a copolymer of butyl acrylate and 2-ethylhexyl acrylate), and silicone rubber (for example, polyorganosiloxane rubber, IPN type rubber comprising a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate rubber component; And rubber having a structure in which the two rubber components are entangled with each other so that they cannot be separated, and an IPN type rubber composed of a polyorganosiloxane rubber component and a polyisobutylene rubber component. Still other rubber components include urethane rubber, amide rubber, phosphazene rubber, and fluorine rubber. The glass transition temperature of the rubber component is preferably 10 ° C. or lower, more preferably −10 ° C. or lower, and further preferably −30 ° C. or lower.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, and methoxystyrene. In particular, styrene is preferable. These may be used alone or in combination of two or more.
Examples of the vinyl cyanide monomer include acrylonitrile and methacrylonitrile, and acrylonitrile is particularly preferable. These may be used alone or in combination of two or more.

  Specific examples of the alkyl (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and amyl (meth). Acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) An acrylate etc. can be mentioned. The notation of (meth) acrylate indicates that both methacrylate and acrylate are included.

  Specifically, the rubber-modified polymer in the present invention includes SB (styrene-butadiene) polymer, ABS (acrylonitrile-butadiene-styrene) polymer, MBS (methyl methacrylate-butadiene-styrene) polymer, MABS (methyl methacrylate). -Acrylonitrile-butadiene-styrene polymer, MB (methyl methacrylate-butadiene) polymer, ASA (acrylonitrile-styrene-acrylic rubber) polymer, AES (acrylonitrile-ethylenepropylene rubber-styrene) polymer, MA (methyl methacrylate-) Acrylic rubber) polymer, MAS (methyl methacrylate-acrylic rubber-styrene) polymer, methyl methacrylate-acrylic butadiene rubber copolymer, methyl methacrylate-acrylic butadiene rubber- Styrene copolymer, methyl methacrylate - and the like (acrylic silicone IPN rubber) polymer. The rubbery polymer is not particularly limited in its structure, but a graft polymer and a block polymer are generally used, and a graft polymer is more preferable. These are widely known as impact modifiers for thermoplastic resins.

  The rubber-modified polymer of the present invention may be produced by any polymerization method including bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization, and the copolymerization method may be a single-stage graft or a multi-stage graft. There is no problem. Moreover, the mixture with the copolymer of only the graft component byproduced in the case of manufacture may be sufficient. Furthermore, examples of the polymerization method include a general emulsion polymerization method, a soap-free polymerization method using an initiator such as potassium persulfate, a seed polymerization method, and a two-stage swelling polymerization method. In the suspension polymerization method, the aqueous phase and the monomer phase are individually maintained, both are accurately supplied to the continuous disperser, and the particle diameter is controlled by the rotation speed of the disperser, and the continuous production is performed. In the method, a method may be used in which the monomer phase is supplied by passing it through a fine orifice having a diameter of several to several tens of μm or a porous filter in an aqueous liquid having dispersibility to control the particle size. In the case of a core-shell type graft polymer, the reaction may be one stage or multistage for both the core and the shell.

As the rubber-modified polymer of the present invention, ABS resin and MBS resin are preferably used.
The ratio of the graft polymerization component grafted to the rubber component of the rubber-modified polymer in the ABS resin and MBS resin (the ratio of the weight of the graft component to the weight of the diene rubber component), that is, the graft ratio (% by weight) is 20 to 200% is preferable, and more preferably 20 to 80%.
Such ABS resin and MBS resin may be produced by any method such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. The copolymerization method may be copolymerized in a single stage or in multiple stages.

  The rubber particle diameter of the rubbery polymer in the ABS resin or MBS resin is preferably 0.05 to 5 μm, more preferably 0.1 to 2.0 μm, and still more preferably 0.2 to 1.5 μm in weight average particle diameter. As the distribution of the rubber particle diameter, either a single distribution or a rubber particle having two or more peaks can be used, and the rubber particles form a single phase in the morphology. Alternatively, it may have a salami structure by containing an occluded phase around the rubber particles.

  The content of the impact modifier (component D) is 1 to 10 parts by weight, preferably 2 to 9 parts by weight, more preferably 3 to 8 parts by weight, based on 100 parts by weight of the thermoplastic polyester resin composed of PBT and PBN. Part. When the content is less than 1 part by weight, the impact resistance and fatigue characteristics are insufficient, and when it exceeds 10 parts by weight, the fatigue characteristics and heat resistance are undesirably lowered.

(Other additives)
The thermoplastic polyester resin composition for planetary gears of the present invention is blended with other thermoplastic resins as long as the effects of the invention are not impaired, and if necessary, a plasticizer, inorganic filler, non-halogen flame retardant, additive Sulfur (crosslinking) agents, pigments, light stabilizers, antistatic agents, antiblocking agents, lubricants, dispersants, fluidity improvers, mold release agents, nucleating agents, neutralizing agents and the like can be added.

(Planetary gear manufacturing method)
Next, an embodiment of a method for manufacturing a planetary gear according to the present invention will be described.
Arbitrary methods are employ | adopted in order to manufacture the thermoplastic polyester resin composition for planetary gears of this invention. For example, each component and optionally other components can be premixed and then melt-kneaded and pelletized. Examples of the premixing means include a Nauter mixer, a V-type blender, a Henschel mixer, a mechanochemical apparatus, and an extrusion mixer. In the preliminary mixing, granulation can be performed by an extrusion granulator or a briquetting machine depending on the case. After the preliminary mixing, the mixture is melt-kneaded by a melt-kneader represented by a vent type twin-screw extruder and pelletized by a device such as a pelletizer. Other examples of the melt kneader include a Banbury mixer, a kneading roll, and a constant-temperature stirring vessel, but a vent type twin screw extruder is preferred. In addition, each component and optionally other components can be independently supplied to a melt-kneader represented by a twin-screw extruder without being premixed.

  A known method can be used for the production method of the planetary gear of the present invention. For example, various planetary gears can be obtained by injection-molding the thermoplastic polyester resin composition for a planetary gear produced as described above to obtain a molded product. Can be manufactured. In such injection molding, not only ordinary molding methods but also injection compression molding, injection press molding, gas assist injection molding, foam molding (including a method of injecting a supercritical fluid), insert molding, in-mold coating molding, heat insulation Examples thereof include mold molding, rapid heating / cooling mold molding, two-color molding, sandwich molding, and ultra-high speed injection molding. In addition, either a cold runner method or a hot runner method can be selected for molding.

Furthermore, the planetary gear of the present invention can be provided with a solid lubricant such as fluorine-based or molybdenum disulfide on the surface of the planetary gear in order to improve low-frequency performance.
The planetary gear of the embodiment described above has excellent slidability, fatigue characteristics, impact resistance, and heat resistance, and is suitable for planetary gears used for home appliance parts, OA parts, and automobile parts, for example.

  The thermoplastic polyester resin composition for planetary gears of the present invention has excellent slidability, fatigue characteristics, impact resistance, and heat resistance, and is therefore suitable as a resin for planetary gears, and the effects thereof are extremely high. It ’s big.

It is the pin-shaped test piece used for evaluation of slidability. It is the planetary gear created in the Example.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Modes for carrying out the present invention will be described below. However, the embodiments are exemplarily shown, and various modifications can be made without departing from the technical idea of the present invention.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these. Various physical properties were measured by the following methods.

1. Evaluation of Resin Composition (1) Impact Resistance After drying the composition pellets at 120 ° C. for 5 hours, an injection molding machine (manufactured by Mitsubishi Heavy Industries, Ltd .: 80MSP-5) at a cylinder temperature of 280 ° C. and a mold temperature of 90 ° C. A test piece was molded and Charpy impact strength with a notch was measured according to ISO179. The Charpy impact strength needs to be 6 or more.

(2) Fatigue properties After the composition pellets were dried at 120 ° C for 5 hours, a test piece was molded at an injection molding machine (Mitsubishi Heavy Industries, Ltd .: 80MSP-5) at a cylinder temperature of 280 ° C and a mold temperature of 90 ° C. A bending fatigue test was performed according to ASTM D671, and the repeated stress at the time of 10 million repetitions was obtained. The stress needs to be 12 MPa or more.

(3) Heat resistance After the composition pellets were dried at 120 ° C for 5 hours, a test piece was molded at an injection molding machine (Mitsubishi Heavy Industries, Ltd .: 80MSP-5) at a cylinder temperature of 280 ° C and a mold temperature of 90 ° C. According to ISO75-1 and 2, the deflection temperature under load was measured with a load of 0.45 MPa. The deflection temperature under load needs to be 90 ° C. or higher.

(4) Sliding property After drying the composition pellets at 120 ° C. for 5 hours, the injection temperature (Mitsubishi Heavy Industries, Ltd .: 80MSP-5) was used, and the cylinder temperature was 280 ° C., the mold temperature was 90 ° C., and the length was 150 mm × width. A plate-like test piece of 150 mm × thickness 2 mm (a gate is a fin gate having a width 40 mm × thickness 1 mm from one end of the side) was prepared by injection molding. Next, the center part of the test piece was cut to a length of 50 mm and a width of 100 mm, and the cut test piece was fixed on a base that reciprocates. Moreover, the pin-shaped test piece shown in FIG. 1 is produced by injection molding using the mating material, and the tip spherical surface portion of the pin-shaped test piece is placed on the flat surface portion of the cutting test piece of the flat plate-shaped test piece. It contacted in the state which applied 1 kg of load loads in the state where the cylinder axis direction and the plane normal direction of a flat-plate-shaped test piece become parallel. In this contact state, in an atmosphere of 23 ° C. and relative humidity of 50% RH, a reciprocating wear friction tester (manufactured by Orientec Co., Ltd .: AFT-15M) was used to reciprocate 1000 times at a test speed of 20 mm / sec and a stroke width of 20 mm. Made it work. The coefficient of dynamic friction after 1000 operations was determined from the friction force after 1000 operations. The smaller the coefficient of dynamic friction, the better the slidability, and 0.7 or less is required. In addition, two types, PBT-1 and POM, were used as the counterpart material.

[Examples 1 to 4, Comparative Examples 1 to 11]
Components A, B, C, and D described in Table 1 were mixed with a V-type blender to prepare a mixture. Using a vent type twin screw extruder with a screw diameter of 30 mm [Nippon Steel Works TEX-30XSST], the mixture mixed in the V-type blender was measured at a predetermined ratio from the first input port at the end with a meter. Then, it was melt-extruded at a cylinder temperature of 290 ° C. under a vacuum of 3 kPa using a vacuum pump, and pelletized. The obtained pellets were dried with a hot air circulation dryer at a drying temperature of 120 ° C. for 6 hours and evaluated with an injection molding machine [Mitsubishi Heavy Industries, Ltd .: 80MSP-5] at a cylinder temperature of 280 ° C. and a mold temperature of 90 ° C. The test piece for this was created and evaluated by said evaluation method.
The POM of the comparative example had a drying temperature of 90 ° C., a cylinder temperature of 210 ° C., and a mold temperature of 90 ° C.
The results are shown in Table 1.

In addition, the detail of each used component is as follows.
(Component A: polybutylene naphthalate resin)
PBN-1: Polybutylene naphthalate resin <Production example>
2,5-naphthalenedicarboxylic acid dimethyl ester (315.0 parts), 1.4-butanediol (200, 0 parts) and tetra-n-butyl titanate (0.062 parts) were placed in a transesterification reaction vessel. The ester exchange reaction was carried out for 150 minutes while raising the temperature. Subsequently, the obtained reaction product was transferred to a polycondensation reaction tank to start a polycondensation reaction. In the polycondensation reaction, the pressure in the polycondensation reaction layer is gradually reduced from normal pressure to 0.13 kPa (1 Torr) or less over 40 minutes, and the temperature is simultaneously raised to a predetermined reaction temperature of 260 ° C. Thereafter, the polycondensation reaction temperature is 260 ° C. The polycondensation reaction was carried out for 140 minutes while maintaining the temperature of 0.1 ° C. and the pressure of 0.13 kPa (1 Torr). When 140 minutes had elapsed, the polycondensation reaction was completed, PBN was extracted in a strand shape, and cut into chips using a cutter while cooling with water. Next, the obtained PBN 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. The obtained PBN (PBN-1) had an intrinsic viscosity of 1.10 dl / g and a terminal carboxyl group concentration of 16 eq / ton.

(B component: polybutylene terephthalate resin)
PBT-1: manufactured by Polyplastics Co., Ltd. Product name: 500FP EF201R (IV = 0.86 dl / g terminal carboxyl group concentration 12 eq / ton)
PBT-2: manufactured by Polyplastics Co., Ltd. Product name: 300FP EF201R (IV = 0.66 dl / g terminal carboxyl group concentration 20 eq / ton)
PBT-3: manufactured by Polyplastics Co., Ltd. Product name: 700FP EF201R (IV = 1.14 dl / g terminal carboxyl group concentration 9 eq / ton)
PBT-4: manufactured by Polyplastics Co., Ltd. Trade name: 500FP EF202X (IV = 0.87 dl / g terminal carboxyl group concentration 50 eq / ton)
PBT-5: Polybutylene terephthalate resin prepared by the following production method (IV = 0.67 dl / g, terminal carboxyl group concentration 16 eq / ton)
<Manufacturing Method> 35.0 parts of dimethyl terephthalate, 22.9 parts of 1.4-butanediol, 0.026 part of tetra-n-butyl titanate are placed in a transesterification reaction tank, and the transesterification reaction tank is 170 ° C. The ester exchange reaction was carried out for 180 minutes while raising the temperature. Subsequently, the obtained reaction product was transferred to a polycondensation reaction tank to start a polycondensation reaction. In the polycondensation reaction, the pressure in the polycondensation reaction layer is gradually reduced from normal pressure to 0.13 kPa (1 Torr) or less over 40 minutes, and the temperature is raised to a predetermined reaction temperature of 240 ° C. The polycondensation reaction was carried out for 140 minutes while maintaining the state of 0.13 kPa (1 Torr) at 0 ° C. When 170 minutes passed, the polycondensation reaction was completed, and PBT was extracted in a strand shape, and cut into chips using a cutter while cooling with water.

(C component: antioxidant)
C-1: IRGANOX 1076 (hindered phenol antioxidant) manufactured by Ciba Specialty Chemicals Co., Ltd.
C-2: ADK STAB PEP-24G (phosphite antioxidant) manufactured by Asahi Denka Kogyo Co., Ltd.
(D component: impact modifier)
D-1: Rohm and Haas Co., Ltd., trade name: Paraloid EXL-2620 (MBS resin)
(Other ingredients)
CB: Koshigaya Kasei Co., Ltd., trade name: ROYALBLACK904S (carbon black master: carbon black 40% by weight, PS resin 60% by weight)
POM: manufactured by Polyplastics Co., Ltd., trade name: M90-44 (polyacetal resin)

  In Table 1, Examples 1-4 in which a specific antioxidant and an impact modifier are blended with a polybutylene naphthalate resin and a polybutylene terephthalate resin having a specific range of terminal carboxyl group concentration and intrinsic viscosity are impact resistant. It is found that the present invention is an industrially useful and excellent thermoplastic polyester resin composition for planetary gears because it has properties, fatigue properties, heat resistance, and slidability.

  In Table 1, Comparative Example 1 is inferior in slidability with polybutylene terephthalate because PBN is less than the scope of the present invention and PBT is greater than the scope of the present invention. Since the comparative example 2 has more PBN than the range of this invention and PBT less than the range of this invention, it is inferior to heat resistance. Since the comparative example 3 used PBT whose terminal carboxyl group density | concentration is higher than this invention range and whose intrinsic viscosity is lower than this invention range, it is inferior to impact resistance. Since the comparative example 4 used PBT whose intrinsic viscosity is higher than the range of this invention, it is inferior to heat resistance. Since the comparative example 5 used PBT whose terminal carboxyl group density | concentration is higher than the range of this invention, it is inferior to impact resistance. Since Comparative Example 6 has less antioxidant than the range of the present invention, the impact resistance and fatigue characteristics are inferior. Since Comparative Example 7 has more antioxidants than the range of the present invention, the impact resistance and fatigue characteristics are inferior. Comparative Example 8 is inferior in impact resistance and fatigue characteristics because the impact modifier is less than the range of the present invention. Since Comparative Example 9 has more impact modifiers than the range of the present invention, it is inferior in fatigue characteristics and heat resistance. Since the comparative example 10 is a polyacetal, it is inferior in slidability with the polyacetal which is the same kind material. Since the comparative example 11 used PBT whose intrinsic viscosity is lower than the range of this invention, it is inferior to impact resistance.

  Furthermore, the planetary gear shown in FIG. 2 (outer diameter: 19.2 mm, thickness: 1.8 mm, number of teeth: 30) was created by injection molding the resin composition described in Example 1. This gear was used in a gear mechanism having a sun gear made of polybutylene terephthalate resin at the center and an internal gear made of polyacetal around the planetary gear, but there was no problem in operation.

DESCRIPTION OF SYMBOLS 1 Gate 2 Sun gear 3 made from polybutylene terephthalate resin Planetary gear 4 which consists of resin composition as described in this Example 4 Internal gear made from polyacetal

Claims (3)

  (A) Polybutylene naphthalate resin (component A) 50 to 95 parts by weight and (B) a terminal carboxyl group concentration of 18 eq / ton or less and an intrinsic viscosity of 0.7 to 1.1 dl / g Selected from the group consisting of (C) a phosphite compound, a phosphate compound, a phosphonite compound and a hindered phenol compound for 100 parts by weight of a thermoplastic polyester resin comprising 50 to 5 parts by weight of a terephthalate resin (component B) A thermoplastic polyester resin composition for planetary gears containing 0.001 to 5 parts by weight of at least one antioxidant (C component) and 1 to 10 parts by weight of (D) impact modifier (D component).   The D component is a rubber-modified polymer obtained by polymerizing at least one selected from the group consisting of an aromatic vinyl monomer, a vinyl cyanide monomer, and an alkyl (meth) acrylate monomer on a rubber component. The thermoplastic polyester resin composition for planetary gears according to claim 1.   A planetary gear comprising the thermoplastic polyester resin composition for a planetary gear according to claim 1 or 2.

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