JP2017172794A - Thermoplastic polyester elastomer resin composition for resin belt material and resin belt molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester elastomer resin composition for resin belt material which has high resin strength and is excellent in bending fatigue resistance and moldability.SOLUTION: A thermoplastic polyester elastomer resin composition for resin belt material includes a thermoplastic polyester elastomer (A) as the thermoplastic polyester elastomer resin composition having a melting point of 190 to 225°C of 80 to 92.99 wt.%, glass fiber (B) of 7 to 15 wt.% and crystal nucleus agent (C) of 0.01 to 5.0 wt.% and has a difference between the melting point and crystallization temperature of 25°C or less.SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic polyester elastomer resin composition for resin belt materials and a resin belt molded article having excellent bending resistance, high resin strength, and excellent moldability.

  A polyester block copolymer having a crystalline aromatic polyester unit as a hard segment and an aliphatic polyether unit such as poly (alkylene oxide) glycol and / or an aliphatic polyester unit such as polylactone as a soft segment has a strength, Excellent mechanical properties such as impact resistance, elastic recovery, and flexibility, low temperature and high temperature characteristics, and thermoplasticity makes it easy to mold, so it can be used in fields such as automobiles, electrical / electronic parts, and consumer goods. Widely used.

  Among these characteristics, it is excellent in strength, flexibility and bending resistance, and is easy to be molded, so it is used as a resin belt material. An example of a resin belt is a toothed belt, which has a structure in which teeth are meshed with a gear and the belt slides by rotation of the gear. Since sliding operation is repeated during use, belt strength and bending fatigue resistance are particularly important in this method of use.

  However, in general, when the resin strength is increased, the bending fatigue resistance is decreased, and when the resin strength is increased, the resin strength is decreased. Therefore, there is a method (for example, Patent Document 1) in which the molecular weight is increased to improve the bending fatigue resistance of the resin, and the strength is compensated by covering the belt with a canvas. Further, a method for increasing the resin strength by adding glass fiber to a thermoplastic elastomer is known (Patent Document 2).

JP 2006-206791 A JP-A-8-169894

  However, in the case of the method of Patent Document 2, there is a concern that the bending fatigue resistance is lowered. Further, since the belt strength is affected by the dimensions of the belt molded product, it is an important issue to prevent sink marks during molding.

  Accordingly, an object of the present invention is to solve the above-mentioned problems in the prior art, to improve the bending fatigue resistance while maintaining the resin strength, and to be excellent in moldability thermoplastic polyester elastomer resin composition for resin belt materials and It is an object of the present invention to provide a resin belt molded body made of them.

  In order to solve the above problems, the present invention employs the following means. That is, the thermoplastic polyester elastomer resin composition for a resin belt material of the present invention is a thermoplastic polyester elastomer resin composition having a melting point of 190 to 225 ° C., and 80 to 99.99 weight of the thermoplastic polyester elastomer (A). %, Glass fiber (B) 7 to 15% by weight, crystal nucleating agent (C) 0.01 to 5.0% by weight, and the difference between the melting point and the crystallization temperature is 25 ° C. or less. Preferably, the thermoplastic polyester elastomer (A) is a low melting point polymer segment comprising 50 to 85% by weight of a high melting point crystalline polymer segment (a1) comprising a crystalline aromatic polyester unit and an aliphatic polyether unit. (A2) A polyester block copolymer containing 15 to 50% by weight.

  More preferably, the melt flow rate at a temperature 20 ° C. higher than the melting point of the thermoplastic polyester elastomer resin composition is 1 to 10 g / 10 min.

  Moreover, the resin belt molded body of the present invention is characterized by comprising such a thermoplastic polyester elastomer resin composition for a resin belt material.

  According to the present invention, as described below, a polyester elastomer resin composition for a resin belt material having high resin strength and excellent bending fatigue resistance and moldability can be obtained.

  The present invention will be described below.

  The thermoplastic polyester elastomer (A) used in the present invention comprises a high melting point crystalline polymer segment (a1) mainly composed of crystalline aromatic polyester units and a low melting point segment (a2) mainly composed of aliphatic polyether units. The high-melting crystalline polymer segment is a polyester formed mainly from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof.

  Examples of the aromatic dicarboxylic acid or its ester-forming derivative include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, anthracene dicarboxylic acid, diphenyl-4,4. Examples include '-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 5-sulfoisophthalic acid, and sodium 3-sulfoisophthalate. In the present invention, the aromatic dicarboxylic acid is mainly used. A part of the aromatic dicarboxylic acid is an alicyclic ring such as 1,4-cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, or 4,4′-dicyclohexyldicarboxylic acid. Or aliphatic dicarboxylic acids such as adipic acid, succinic acid, oxalic acid, sebacic acid, dodecanedioic acid, and dimer acid. Furthermore, ester-forming derivatives of dicarboxylic acids such as lower alkyl esters, aryl esters, carbonates, and acid halides can of course be used equally.

  As the dicarboxylic acid component, the aromatic dicarboxylic acid or an ester-forming derivative thereof is preferably terephthalic acid or dimethyl terephthalate, and more preferably terephthalic acid.

  Examples of the diol or ester-forming derivatives thereof include diols having a molecular weight of 400 or less, such as 1,4-butanediol, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol and the like. Diols, 1,1-cyclohexanedimethanol, 1,4-dicyclohexanedimethanol, alicyclic diols such as tricyclodecane dimethanol, and xylylene glycol, bis (p-hydroxy) diphenyl, bis (p-hydroxy) ) Diphenylpropane, 2,2′-bis [4- (2-hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxyethoxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxyethoxy) Aromatic diols such as phenyl] cyclohexane, 4,4′-dihydroxy-p-terphenyl, and 4,4′-dihydroxy-p-quarterphenyl are preferred, and such diols are ester-forming derivatives such as acetyl, alkali It can also be used in the form of a metal salt or the like.

  Two or more of these dicarboxylic acids, derivatives thereof, diol components and derivatives thereof may be used in combination.

  Preferred examples of such a high-melting crystalline polymer segment (a1) include polybutylene terephthalate units derived from terephthalic acid or dimethyl terephthalate and 1,4-butanediol, isophthalic acid or dimethyl isophthalate and 1,4-butane. Those composed of polybutylene isophthalate units derived from diol are preferably used. The copolymerization amount of the high-melting crystalline polymer segment (a1) is usually 50 to 85% by weight, preferably 60 to 80% by weight.

  As the low-melting polymer segment (a2) used in the thermoplastic polyester elastomer (A) used in the present invention, an aliphatic polyether can be used as necessary.

  Specific examples of such aliphatic polyethers include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (trimethylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, ethylene oxide and Examples include a copolymer of propylene oxide, an ethylene oxide adduct of poly (propylene oxide) glycol, and a copolymer of ethylene oxide and tetrahydrofuran. Of these, poly (tetramethylene oxide) glycol and / or poly (propylene oxide) glycol ethylene oxide adducts and / or copolymers of ethylene oxide and tetrahydrofuran are preferably used.

  The copolymerization amount of the low-melting polymer segment (a2) of the (A) thermoplastic polyester elastomer used in the present invention is usually 15 to 50% by weight, preferably 20 to 40% by weight.

  The thermoplastic polyester elastomer (A) used in the present invention can be produced by a known method. Specific examples thereof include, for example, a method of subjecting a lower alcohol diester of a dicarboxylic acid, an excessive amount of a low molecular weight glycol and a low melting point polymer segment component to a transesterification reaction in the presence of a catalyst, and subjecting the resulting reaction product to melt polycondensation. In addition, any method may be employed such as a method in which an esterification reaction is performed between a dicarboxylic acid, an excess amount of glycol, and a low melting point polymer segment component in the presence of a catalyst, and the resulting reaction product is melt polycondensed.

  The thermoplastic polyester elastomer (A) obtained by polycondensation may then be subjected to solid phase polycondensation. The solid phase polycondensation is carried out at a temperature at which the thermoplastic polyester elastomer (A) pelletized after the melt polycondensation is not fused, but is usually carried out in a temperature range of 140 ° C to 220 ° C. Prior to solid phase polycondensation, it is desirable to go through a precrystallization and drying step. The solid phase polycondensation is carried out under high vacuum or under an inert air stream. In the case of high vacuum, it is preferably performed under a reduced pressure of 665 Pa or less, more preferably 133 Pa or less. In the case of an inert air stream, it is typically preferable to carry out under a nitrogen stream, and the pressure is not particularly limited, but atmospheric pressure is preferred. As the reaction vessel, it is preferable to use a rotatable vacuum dryer or a tower dryer capable of flowing an inert gas.

  The glass fiber (B) used in the present invention is a chopped strand type or roving type glass fiber, such as a silane coupling agent such as an aminosilane compound or an epoxysilane compound and / or a bisphenol A diglycidyl ether or a novolac epoxy compound. Glass fibers treated with a sizing agent containing one or more epoxy compounds are preferably used.

  The average fiber diameter of the glass fiber (B) is preferably 5 to 20 μm. Although there is no restriction | limiting in particular in the average fiber length of glass fiber (B), 0.1-20 mm is preferable and 0.1-5 mm is more preferable.

  The compounding quantity of glass fiber (B) is 7 to 15 weight% with respect to 100 weight part of thermoplastic elastomers (A).

  The crystal nucleating agent (C) used in the present invention is not particularly limited as long as it is unmelted at the time of melt processing and can become a crystal nucleus in the cooling process, but is preferably an inorganic substance, and in particular a plate-like filler. A granular filler is preferably used. Specific examples of the plate-like filler include talc, mica, and glass flakes, and specific examples of the granular filler include calcium carbonate, clay, barium sulfate, and glass beads.

  The compounding amount of the crystal nucleating agent (C) is 0.01 to 5% by weight with respect to 100 parts by weight of the thermoplastic elastomer (A).

  Further, the belt strength can be improved by further adding a polyester resin (D) to the thermoplastic polyester elastomer resin composition for a resin belt material of the present invention.

  The polyester resin (D) used in the present invention is at least one acid component selected from terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, etc., ethylene glycol, propylene glycol, butylene glycol, hexylene. It is obtained by polycondensation with at least one diol component selected from glycol and the like, and specifically, polybutylene terephthalate (PBT), polypropylene terephthalate (PPT), polyethylene terephthalate (PET), polyhexylene terephthalate (PHT), polyethylene naphthalate, polybutylene naphthalate (PBN), polycyclohexane-1,4-dimethylol terephthalate, polyethylene isophthalate / terephthalate (PET / I), poly , And the like styrene (terephthalate isophthalate) (PET / I) copolymerized polyesters such as. Among these polyester resins, polyethylene terephthalate, polybutylene terephthalate, polybutylene naphthalate, and polybutylene (terephthalate / isophthalate) are preferable, and polybutylene terephthalate is more preferable.

  The compounding quantity of a polyester resin (D) is 5-25 weight% with respect to 100 weight part of thermoplastic elastomers (A).

  In addition, the polyester elastomer resin composition of the present invention includes an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a lubricant, a dye, a pigment, a plasticizer, a difficulty agent, and the like as long as the purpose is not impaired. Additives such as a flame retardant, a release agent, and silicone oil can be added.

  The effects of the present invention will be described below with reference to examples. The present invention can be implemented with appropriate modifications within the scope of the gist of the present invention. In the examples, “%” and “parts” are based on weight unless otherwise specified. The physical properties shown in the examples are measured by the following measuring methods.

[Hardness (Durometer D)]
Pellets dried in hot air at 90 ° C for 3 hours or more using an injection molding machine (NEX-1000 manufactured by Nissei Plastic Industries) under the conditions of a cylinder temperature of 240 ° C and a mold temperature of 50 ° C, length 120 x width 75 x thickness 2mm A thick square plate was molded and measured according to JIS K7215 durometer D hardness.

[Melting point and crystallization temperature]
Using DSC Q100 manufactured by TA Instruments Inc., heated from 40 ° C. to 250 ° C. at a heating rate of 20 ° C./min in a nitrogen atmosphere, held at 250 ° C. for 3 minutes, and then 10 ° C./min. It cooled to 40 degreeC with the temperature-fall rate, and measured crystallization temperature.
Furthermore, the top temperature of the melting peak when heated to 250 ° C. at a rate of temperature increase of 10 ° C./min was measured.

[Melt flow rate]
According to ASTM D1238, the temperature was 20 ° C. higher than the melting point of the pellets, and the load was 2160 g.

[Tensile breaking strength, tensile breaking elongation]
JISK7112 dumbbell specimens were molded from hot-dried pellets at 90 ° C for 3 hours or more using an injection molding machine (NEX-1000 manufactured by Nissei Plastic Industries) under the molding conditions of cylinder temperature 240 ° C and mold temperature 50 ° C. Molded and measured according to JIS K7113 (1995 edition).

[Bending fatigue]
Pellets dried with hot air at 90 ° C. for 3 hours or more using an injection molding machine (NEX-1000 manufactured by Nissei Plastic Industries) under molding conditions of cylinder temperature 240 ° C. and mold temperature 50 ° C. 120 × 75 × From a 2 mm thick square, a strip of 50 x 6 x 2 mm is cut out and stroked at a distance between chucks of 30 mm to 20 mm in a 23 ° C atmosphere using a demature bending fatigue tester, leading to breakage. The number of bends up to was measured.

[Extrudability]
A pellet was dried with hot air at 90 ° C. for 3 hours or more, and a resin belt was molded at a temperature of 220 to 250 ° C. using a single screw extruder. Measure the external dimensions of the belt,
◯: Evaluation was made with a rank of 1% or less in the belt center, and x: more than 1% in the belt center.

[Production of Polyester Elastomer (A-1)]
593 parts of terephthalic acid as the high melting crystalline polymer segment (a1), 537 parts of 1,4-butanediol and 229 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400 as the low melting polymer segment (a2) , Charged in a reaction vessel equipped with a helical ribbon type stirring blade together with 0.3 part of titanium tetrabutoxide and 0.2 part of mono-n-butyl-monohydroxytin oxide, and heated at 190-225 ° C. for 3 hours to give reaction water. The esterification reaction was carried out while distilling out of the system. To the reaction mixture, 2.0 parts of titanium tetrabutoxide was added, 0.5 parts of “Irganox” 1098 (hindered phenol antioxidant manufactured by Ciba Geigy Co.) was added, the temperature was raised to 245 ° C., and then 50 parts. The pressure in the system was reduced to 0.2 mmHg over a period of time, and melt polycondensation was performed for 2 hours and 45 minutes under the conditions. The obtained polyester elastomer (A-1) was discharged in the form of strands into water, and was cut into pellets. The weight percentage of the high-melting crystalline polymer segment (a1) was 75, and the weight percentage of the low-melting polymer segment (a2) was 25.

[Production of polyester elastomer (A-2)]
638 parts of terephthalic acid as the high melting crystalline polymer segment (a1), 586 parts of 1,4-butanediol and 165 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400 as the low melting point polymer segment (a2) , Charged in a reaction vessel equipped with a helical ribbon type stirring blade together with 0.3 part of titanium tetrabutoxide and 0.2 part of mono-n-butyl-monohydroxytin oxide, and heated at 190-225 ° C. for 3 hours to give reaction water. The esterification reaction was carried out while distilling out of the system. After adding 2.0 parts of titanium tetrabutoxide to the reaction mixture and adding 0.5 parts of “Irganox” 1098 (Hindered Phenolic Antioxidant manufactured by Ciba Geigy), the temperature was raised to 245 ° C., Subsequently, the pressure in the system was reduced to 0.2 mmHg over 50 minutes, and melt polycondensation was performed for 2 hours and 45 minutes under the conditions. The obtained polyester elastomer (A-2) was discharged into water in the form of a strand and cut into pellets. The weight percentage of the high-melting crystalline polymer segment (a1) was 82, and the weight percentage of the low-melting polymer segment (a2) was 18.

[Production of Polyester Elastomer (A-3)]
505 parts of terephthalic acid as the high melting crystalline polymer segment (a1), 438 parts of 1,4-butanediol and 354 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400 as the low melting polymer segment (a2) , Charged in a reaction vessel equipped with a helical ribbon type stirring blade together with 0.3 part of titanium tetrabutoxide and 0.2 part of mono-n-butyl-monohydroxytin oxide, and heated at 190-225 ° C. for 3 hours to give reaction water. The esterification reaction was carried out while distilling out of the system. After adding 2.0 parts of titanium tetrabutoxide to the reaction mixture and adding 0.5 parts of “Irganox” 1098 (Hindered Phenolic Antioxidant manufactured by Ciba Geigy), the temperature was raised to 245 ° C., Subsequently, the pressure in the system was reduced to 0.2 mmHg over 50 minutes, and melt polycondensation was performed for 2 hours and 45 minutes under the conditions. The obtained polyester elastomer (A-3) was discharged into water in the form of a strand and cut into pellets. The weight percentage of the high-melting crystalline polymer segment (a1) was 61, and the weight percentage of the low-melting polymer segment (a2) was 39.

[Production method of polyester elastomer (A-4)]
Polyester elastomer (A-1) pellets were charged into a rotatable reaction vessel, the pressure in the system was reduced to 27 Pa, and heating was carried out at 170 to 180 ° C. for 48 hours to perform solid phase polycondensation. The melt flow rate of the obtained polyester elastomer (A-4) pellets was 2 g / 10 minutes as measured at 240 ° C. under a load of 2160 g.

[Glass fiber (B)]
Nittobo Co., Ltd. chopped strand glass fiber CS3J948 was used. Fiber diameter is about 10 μm.

[Crystal nucleus material (C)]
Hytron (hydrous magnesium silicate) manufactured by Takehara Chemical Industry Co., Ltd. was used. The average particle size is 4 μm.

[Polyester resin (D)]
Toraycon 1100S (manufactured by Toray Industries, Inc.), which is a polybutylene terephthalate (PBT) resin, was used.

[Examples 1 to 6]
Using a twin screw extruder having a 45 mm diameter screw, the polyester elastomers (A-1), (A-2), (A-3), (A-4) shown in the reference examples and crystals as necessary The core material (C) and the polyester resin (D) were mixed with the composition shown in Table 1 and added from the original filling portion. Moreover, the side feeder was installed in the middle of the original containing part and the vent part, and glass fiber (B) was added by the addition amount shown in Table 1 similarly to the above. A thermoplastic polyester elastomer resin composition for a resin belt material was obtained by melt mixing under extrusion conditions of 250 ° C. and screw rotation of 150 rpm, discharging into a strand, passing through a cooling bath, and pelletized by a strand cutter.

  The obtained pellets are dried at 80 ° C. for 5 hours and then injection-molded under conditions of a cylinder temperature of 230 ° C. to 250 ° C. and a mold temperature of 50 ° C. for hardness, tensile rupture strength, tensile rupture elongation, and bending fatigue resistance test. The test piece was obtained. Various tests were carried out using the obtained test pieces instead of the resin belt molded body. The test results are shown in Table 1.

  As is clear from the results in Table 1, the resin belt molded bodies obtained from the thermoplastic polyester elastomer resin compositions for resin belt materials shown in Examples 1 to 4 exhibit excellent bending fatigue properties and high resin strength. Indicated. Furthermore, the extrudability was good and no shrinkage was observed in the obtained product. Moreover, the resin belt molded object obtained from the thermoplastic polyester elastomer resin composition for resin belt materials shown in Examples 5-6 showed the further outstanding bending fatigue property.

[Comparative Examples 1-4]
Using a twin screw extruder having a 45 mm diameter screw, the polyester elastomers (A-1), (A-2), (A-3) shown in the reference examples and, if necessary, the crystal nucleus (C) The polyester resin (D) was mixed with the composition shown in Table 1 and added from the original filling portion. Moreover, the side feeder was installed in the middle of the original containing part and the vent part, and glass fiber (B) was added by the addition amount shown in Table 1 similarly to the above. A thermoplastic polyester elastomer resin composition was obtained by melt mixing under heating conditions of 250 ° C. and screw rotation of 150 rpm, discharging into a strand, passing through a cooling bath, and pelletized by a strand cutter.

  The obtained pellets are dried at 80 ° C. for 5 hours and then injection-molded under conditions of a cylinder temperature of 230 ° C. to 250 ° C. and a mold temperature of 50 ° C. for hardness, tensile rupture strength, tensile rupture elongation, and bending fatigue resistance test. The test piece was obtained. Various tests were carried out using the obtained test pieces instead of the resin belt molded body. The test results are shown in Table 2.

As is apparent from the results in Table 2, the resin belt molded body obtained from the thermoplastic polyester elastomer resin composition of Comparative Examples 1 to 4 that does not satisfy the conditions of the present invention is the thermoplastic polyester for resin belt material of the present invention. Compared to the resin belt molded body obtained from the elastomer resin composition, any of tensile rupture strength, bending fatigue resistance, and extrusion moldability is inferior. In Comparative Example 1, the resin strength was insufficient, and in Comparative Example 2, the bending fatigue property was inferior. Further, in Comparative Examples 3 and 4, since the time until crystallization becomes long, shrinkage occurred in the obtained product, and the dimensional standard could not be satisfied.

Claims (6)

A thermoplastic polyester elastomer resin composition having a melting point of 190 to 225 ° C, wherein the thermoplastic polyester elastomer (A) is 80 to 99.99% by weight, the glass fiber (B) is 7 to 15% by weight, a crystal nucleating agent ( C) A thermoplastic polyester elastomer resin composition for resin belt materials, comprising 0.01 to 5.0% by weight and having a difference between the melting point and the crystallization temperature of 25 ° C. or less. The thermoplastic polyester elastomer (A) comprises 50 to 85% by weight of a high melting point crystalline polymer segment (a1) composed of a crystalline aromatic polyester unit and a low melting point polymer segment (a2) composed of an aliphatic polyether unit. The thermoplastic polyester elastomer resin composition for a resin belt material according to claim 1, which is a polyester block copolymer containing 15 to 50% by weight. The thermoplastic polyester elastomer resin composition for resin belt materials according to claim 1 or 2, further comprising 5 to 25% by weight of a polyester resin (D) with respect to the thermoplastic polyester elastomer resin composition. The thermoplastic polyester elastomer resin composition for a resin belt material according to any one of claims 1 to 3, wherein the crystal nucleating agent (C) is an inorganic substance. The heat for a resin belt material according to any one of claims 1 to 4, wherein a melt flow rate at a temperature 20 ° C higher than the melting point of the thermoplastic polyester elastomer resin composition is 1 to 10 g / 10 min. A plastic polyester elastomer resin composition. A resin belt molded article, wherein the thermoplastic polyester elastomer resin composition for a resin belt material according to any one of claims 1 to 5 is molded.