JP2013181152A - Polyester block copolymer resin composition and molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester block copolymer resin composition excellent in moldability and impact resistance.SOLUTION: A resin composition includes 50-80 wt.% of polyester block copolymer (A) comprising a high melting point crystalline polymer segment (a1) composed of crystalline aromatic polyester; and a low melting point polymer segment (a2) comprising an aliphatic polyether unit and/or aliphatic polyester unit; and 20-50 wt.% of hard resin (B). This polyester block copolymer resin composition further satisfies the following conditions (1)-(4): (1) the viscosity (Pa s) is 40 or less, (2) the isothermal crystallization time is 1.0 min or less, (3) the ductile breaking is shown under the conditions of test speed 10 m/s, striker diameter 1/2 inch, and test temperature -30°C, and the breaking energy is 20J or more, as measured by the high-speed surface impact test according to ASTM D3763, and (4) the bending modulus measured at 23°C according to ASTM D256 is 400 MPa or more.

Description

  The present invention provides a polyester block copolymer resin composition that has high molding processability suitable for thin wall molding, has excellent durability at low temperatures, and can maintain stable characteristics against environmental changes, and It relates to a molded body.

  Thermoplastic polyester resins represented by polyethylene terephthalate and polybutylene terephthalate are excellent in mechanical properties, fluid processability, chemical resistance, electrical properties, etc., and are widely used in electrical / electronic parts and OA equipment parts. However, its use is considerably limited because of its low impact resistance.

  On the other hand, 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 or an aliphatic polyester unit such as polylactone as a soft segment is molded. It has many advantages such as mechanical properties such as heat resistance, impact resistance, elastic recovery, and flexibility, high temperature characteristics, low temperature characteristics, and adhesiveness, and its uses are for industrial materials such as sheets, films, and fibers, and automobiles. And has expanded to electrical and electronic parts.

  Although it is a polyester block copolymer having such excellent characteristics, many of the characteristics depend on the ratio of the hard segment and the soft segment, which are the copolymer segments to constitute. Therefore, mechanical strength is reduced when the soft segment ratio is increased to exhibit better impact resistance under low temperature conditions, and conversely, the hard segment ratio is increased to exhibit excellent rigidity. However, since the impact resistance under low temperature conditions decreases, there is a limit to achieving both rigidity and impact resistance with the polyester block copolymer alone.

  Therefore, there is an attempt to achieve a balance between rigidity and impact resistance by blending a hard polyester resin and a polyester block copolymer (see, for example, Patent Document 1). According to this attempt, although the characteristics that cannot be achieved with a hard polyester resin or polyester block copolymer alone have been obtained, the impact resistance at low temperature is insufficient because the hard resin is the main component. there were.

  Further, thermoplastic polyamide resins are widely used as thermoplastic polyester resins as resins having both excellent rigidity and toughness, but there is a problem that the rigidity is reduced by water absorption.

  Therefore, an attempt to improve rigidity reduction due to water absorption by introducing an aromatic ring into the structure (for example, see Patent Document 2), or an attempt to suppress rigidity reduction during water absorption by blending an inorganic filler (for example, patents) Document 3) is known. However, according to the former, the introduction of an aromatic ring into the structure can suppress the decrease in rigidity at the time of water absorption, but the impact resistance decreases because the molecule becomes rigid. By blending the agent, it is possible to suppress a decrease in rigidity at the time of water absorption, but the addition of an inorganic filler has a problem that it causes a significant decrease in impact resistance at low temperatures and brittle fracture.

  Further, polyamides 11 and 12 and polyamide elastomers are known as low water-absorbing polyamides. However, the rigidity reduction due to water absorption is still greater than that of polyester resins.

  Furthermore, in recent years, in the fields of electronic and electrical equipment and automobiles, there has been an increasing demand for larger, lighter and thinner resin parts from the viewpoints of higher functionality, cost reduction, and environmental impact reduction. ing. When trying to obtain such a molded body by injection molding, high temperature, high speed, and high pressure conditions are required, and therefore high molding processability is required for the resin material.

  Further, since the rigidity and impact strength of the molded product are reduced due to the thinning, the material is required to have higher rigidity and impact resistance than the conventional molded product. In order to obtain such high moldability, the use of a low molecular weight, low viscosity resin or the addition of a plasticizer can be considered, but in both cases the mechanical properties and impact resistance are reduced. There was a problem.

  Therefore, in the prior art, it is possible to obtain a resin and a molded body that have high moldability suitable for thin-wall molding, have excellent durability at low temperatures, and can maintain stable characteristics against environmental changes. It was difficult.

JP-A-9-3309 JP-A-4-149234 JP 2007-77309 A

  The present invention has been achieved as a result of studying the solution of the problems in the prior art described above as an issue.

  An object of the present invention is a polyester block copolymer resin that has high molding processability suitable for thin-wall molding, has excellent impact resistance at low temperatures, and can maintain stable characteristics against environmental changes. It is in providing a composition and a molded object.

  As a result of sincere studies to achieve the above object, the present inventors have found that the above object can be achieved for the first time by blending a specific amount of a specific hard resin into a specific polyester block copolymer. The invention has been reached.

The present invention comprises as constituent components a high-melting-point crystalline polymer segment (a1) composed of a crystalline aromatic polyester and a low-melting-point polymer segment (a2) composed of an aliphatic polyether unit and / or an aliphatic polyester unit. A resin comprising 50 to 80% by weight of a polyester block copolymer (A) in which the proportion of the low melting point polymer segment (a2) is 25 to 70% by weight and 20 to 50% by weight of a hard resin (B) Viscosity (Pa · s) measured at a measurement temperature of 260 ° C. and a shear rate of 20000 sec ⁻¹ measured according to the following conditions (1) to (4) according to (1) JIS K7199 method: 40 or less (2) Isothermal crystallization time is 1.0 min. (3) In a high-speed surface impact test measured according to the ASTM D3763 method, it shows ductile fracture under the conditions of a test speed of 10 m / s, a striker diameter of 1/2 inch, a test temperature of −30 ° C., and a fracture energy of 20 J or more (4 ) A polyester block copolymer resin composition having a bending elastic modulus at 23 ° C. measured in accordance with ASTM D256 of 400 MPa or more.

  According to the present invention, by blending a specific amount of a specific hard resin with a specific polyester block copolymer resin composition, it has high moldability suitable for thin-wall molding, but also has impact resistance at low temperatures. It is possible to provide a polyester block copolymer resin composition and a molded article that are excellent in the properties and can maintain stable characteristics against environmental changes.

  The polyester block copolymer resin composition and molded product of the present invention are made of an excellent characteristic, and are particularly thin and require high temperature impact resistance at low temperatures. Housings such as battery packs, binding bands, etc. It is most suitable for connector parts and sports applications such as shuttlecocks that require high-speed impact resistance.

  Hereinafter, the present invention will be described in detail.

  The high melting point crystalline polymer segment (a1) of the polyester block copolymer (A) used in the present invention is a polyester formed from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. It is.

  Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, anthracene dicarboxylic acid, diphenyl-4,4′-dicarboxylic acid. , Diphenoxyethane dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 5-sulfoisophthalic acid, sodium 3-sulfoisophthalate, and the like. If necessary, the high melting crystalline polymer segment (a1) may be obtained by converting a part of the aromatic dicarboxylic acid into 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.

  Ester-forming derivatives of dicarboxylic acids, such as lower alkyl esters such as dimethyl esters, diethyl esters, dipropyl esters, dibutyl esters, aryl esters, carbonates, and acid halides, should be used in the same manner as aromatic dicarboxylic acids. it can.

  As the diol, a diol having a molecular weight of 400 or less, for example, an aliphatic diol such as 1,4-butanediol, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, 1,1- Cycloaliphatic diols such as cyclohexanedimethanol, 1,4-dicyclohexanedimethanol, tricyclodecane dimethanol, xylylene glycol, bis (p-hydroxy) diphenyl, bis (p-hydroxyphenyl) propane, 2,2- Bis [4- (2-hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane, 4,4′- Dihydroxy Aromatic diols such as p-terphenyl and 4,4'-dihydroxy-p-quarterphenyl are preferred. The diol can also be used in the form of an ester-forming derivative such as an acetyl form or an alkali metal salt.

  Two or more of these aromatic dicarboxylic acids and derivatives or diol components or ester-forming derivatives thereof may be used in combination.

  Examples of preferred high-melting crystalline polymer segments (a1) are polybutylene terephthalate derived from terephthalic acid and / or dimethyl terephthalate and 1,4-butanediol, naphthalene-2,6-dicarboxylic acid and / or 2, It is polybutylene naphthalate derived from 6-dimethyl naphthalene dicarboxylic acid and 1,4-butanediol, and more preferably exhibits the best effect when polybutylene terephthalate is used.

  The low melting point polymer segment (a2) of the polyester block copolymer (A) used in the present invention is an aliphatic polyether and / or an aliphatic polyester.

  Aliphatic polyethers include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, poly (trimethylene oxide) glycol, and a combination of ethylene oxide and propylene oxide. Examples thereof include a polymer, an ethylene oxide adduct of poly (propylene oxide) glycol, and a copolymer of ethylene oxide and tetrahydrofuran. Examples of the aliphatic polyester include poly (ε-caprolactone), polyenantlactone, polycaprylolactone, and polybutylene adipate. From the elastic properties of the polyester block copolymers obtained from these aliphatic polyethers and / or aliphatic polyesters, poly (tetramethylene oxide) glycol, poly (propylene oxide) glycol ethylene oxide adduct, poly (ε- Caprolactone), polybutylene adipate and the like are preferable, and among these, the best effect is exhibited particularly when poly (tetramethylene oxide) glycol is used.

  The copolymerization amount of the low-melting point polymer segment (a2) of the polyester block copolymer (A) used in the present invention is 25 to 70% by weight of the entire polyester block copolymer (A), preferably 30 to 65% by weight, more preferably 35-60% by weight. When the copolymerization amount of the low melting point polymer segment (a2) is less than 25% by weight, there are problems of insufficient impact resistance and poor compatibility particularly at low temperatures. When the copolymerization amount exceeds 80% by weight, the resin composition and molding Insufficient body rigidity.

  In the present invention, two or more kinds of polyester block copolymers having different compositions may be used in combination.

  The polyester block copolymer (A) used in the present invention can be produced by a known method. For example, a method in which a lower alcohol diester of dicarboxylic acid, an excessive amount of low molecular weight glycol, and a low melting point polymer segment component are transesterified in the presence of a catalyst and the resulting reaction product is polycondensed, or an excess amount of dicarboxylic acid A method of subjecting the resulting glycol and low melting point polymer segment component to an esterification reaction in the presence of a catalyst and polycondensing the resulting reaction product, or preparing a high melting point crystalline segment in advance, A method of adding and randomizing by transesterification, a method of linking a high melting point crystalline segment and a low melting point polymer segment with a chain linking agent, and a poly (ε-caprolactone) in the low melting point polymer segment Addition reaction of ε-caprolactone monomer to melting point crystalline segment Any method such as a method may be used.

  The hard resin (B) used in the present invention is for improving the rigidity of the material. For example, polycarbonate, acrylic resin, styrene resin such as ABS resin and polystyrene, polyester resin, polyamide resin, polyvinyl chloride, When at least one hard resin selected from the group of modified polyphenylene ethers is used, polyester resins are used from the viewpoint of compatibility, and more preferable when polybutylene terephthalate and / or polybutylene naphthalate is used. Demonstrate the effect.

  The blending ratio of the polyester block copolymer (A) and the hard resin (B) in the present invention is such that the total weight of the polyester block copolymer (A) and the hard resin (B) is 100% by weight. The blend (A) is 50 to 80% by weight, and the hard resin (B) is 20 to 50% by weight, preferably, the polyester block copolymer (A) is 55 to 75% by weight, and the hard resin (B) is 25 to 45% by weight. It is. If the polyester block copolymer (A) is less than 50% by weight, the impact resistance at low temperature may be insufficient, and if it exceeds 80% by weight, the resin composition and the molded body may have insufficient rigidity. There is.

In the polyester block copolymer resin composition of the present invention, the viscosity (Pa · s) measured at a measurement temperature of 260 ° C. and a shear rate of 20000 sec ⁻¹ measured according to JIS K7199 method is 40 or less, preferably 25 to 30.

If the viscosity (X) measured at a measurement temperature of 260 ° C. and a shear rate of 20000 sec ⁻¹ is greater than 40, it is difficult to form a thin molded product.

In the polyester block copolymer composition of the present invention, the isothermal crystallization time from the melted state at 250 ° C. is 1.0 min. Or less, preferably 0.5 to 0.75 min. The isothermal crystallization time can be measured by a differential scanning calorimeter (DSC) by the following method. Using a differential scanning calorimeter, 10 mg of a sample is heated and melted at 40 ° C. to 250 ° C. at a temperature rising rate of 50 ° C./min. After holding for 3 minutes, it is rapidly cooled to 160 ° C. at a set temperature drop rate of 200 ° C./min, and the isothermal crystallization time is measured. Here, the isothermal crystallization time is defined as the crystallization time from the temperature drop until the endothermic peak of crystallization appears. Therefore, it can be determined that the shorter the isothermal crystallization time, the faster the crystallization. Isothermal crystallization time is 1.0 min. If it exceeds, burrs are likely to appear on the molded product, the appearance of the molded product is deteriorated, and cracks due to burrs are caused.

  The polyester block copolymer composition of the present invention exhibits ductile fracture under the conditions of a test speed of 10 m / s, a striker diameter of 1/2 inch, and a test temperature of −30 ° C. in a high-speed surface impact test measured according to ASTM D3763 method. The destruction energy is 20J or more. The breaking energy is preferably 25 J or more. If the fracture mode is brittle fracture or the fracture energy is less than 20 J, there is a problem in the impact resistance of the resin composition and the molded body in a low temperature environment.

  The polyester block copolymer composition of the present invention has a flexural modulus at 23 ° C. measured according to ASTM D256 of 400 MPa or more, preferably 500 MPa or more, more preferably 600 MPa or more. When the flexural modulus is less than 400 MPa, the resin composition and the thin molded article have insufficient rigidity.

  In addition, the polyester block copolymer resin composition and molded product of the present invention may be oxidized to a known hindered phenol-based, phosphite-based, thioether-based, amine-based or the like as long as the object of the present invention is not impaired. Anti-blocking agents such as inhibitor, benzophenone, benzotriazole, hindered amine, anti-blocking agent such as polyolefin wax, aliphatic amide compound, aliphatic ester compound, fatty acid metal salt, crystallization nucleating agent such as calcium carbonate and talc , Colorants such as dyes and pigments, UV blockers such as titanium oxide and carbon black, reinforcing agents such as glass fibers and carbon fibers, potassium titanate whiskers, flame retardants, foaming agents, adhesives, adhesion aids, fluorescent agents , A crosslinking agent, a surfactant and the like can be optionally contained.

  The polyester block copolymer resin composition and molded product of the present invention are effective for various molded products for automobiles, electronic / electric equipment, precision equipment, and general consumer goods, taking advantage of the above-described excellent properties, High-speed impact resistance is required for automotive interiors and exteriors that are particularly thin and require impact resistance at low temperatures, and for electronics and electricity, housings such as battery packs, cable ties, connector parts, and thin molded products. Ideal for sports applications such as shuttlecocks.

  The effects of the present invention will be described below with reference to examples. All percentages and parts in the examples are based on weight unless otherwise specified. The physical properties shown in the examples were measured as follows.

[Melt viscosity]
It measured according to JIS K7199 method. The measurement was performed at 260 ° C. and a shear rate of 20000 sec ⁻¹ using an orifice having a pore diameter of 0.5 mm and a flow path length of 5 mm using a capillograph manufactured by Toyo Seiki Co., Ltd.

[Isothermal crystallization time]
About 10 mg of the obtained polyester composition was put into a measurement container, and a differential scanning calorimeter “Q100” manufactured by TA Instruments Co., Ltd. was used, and a nitrogen gas flow rate was 50 mL / min, and a heating rate was 50 ° C./min. To 250 ° C. and hold at 250 ° C. for 3 minutes. Thereafter, the temperature was rapidly lowered to 160 ° C. at 200 ° C./min and held, and the time from when the temperature was lowered until the endothermic peak of crystallization appeared was defined as the crystallization time.

[Bending elastic modulus]
It measured using the test piece produced using the electric injection molding machine NEX-1000 (made by Nissei Plastic Industry Co., Ltd.) according to ASTM D256.

[High-speed surface impact test]
The test piece was obtained by cutting out a 6 mm square from a 2 mm thick press sheet produced under the condition of 240 ° C. The surface impact test value of this molded piece was measured according to ASTM D3763 using a high-speed impact tester, Shimadzu HITS (manufactured by Shimadzu Corporation) under the conditions of a test speed of 10 m / s, a striker diameter of 1/2 inch, and a test temperature of -30 ° C. The breaking energy was measured. In addition, as described below, the fracture mode is ductile: no fracture or breakage occurs, and plastic deformation occurs before fracture. Brittleness: The fracture type is broken and cracks are broken sharply and the flexibility is not seen. did.

[Formability]
Using an electric injection molding machine NEX-1000 (manufactured by Nissei Plastic Industries Co., Ltd.) and a molded product mold having a thinnest portion of 0.2 mm thickness, a flow length of 50 mm, and a number of stitch structures, a molding temperature of 260 ° C., Injection molding is performed under the conditions of an injection speed of 300 mm / sec and a mold temperature of 85 ° C., and the following criteria are: ○ Extremely good △ Slight burrs can be confirmed, but there are no problems X Burr is severe and problematic − Viscosity at melting The moldability, which was high and could not be molded, was evaluated.

[Environmental stability]
A JIS K7113 dumbbell injection test piece (2 mm thickness) molded under the conditions of a molding temperature of 240 ° C., a mold temperature of 50 ° C., and an injection speed of 30 mm / sec was dried in an 80 ° C. vacuum dryer for 24 hours and completely dried. The test piece weight and tensile modulus (JIS K7113) were measured. Subsequently, water was absorbed in a high-temperature and high-humidity tank at 40 ° C. and 80 Rh%, and the weight of the test piece in saturation and the tensile elastic modulus (JIS K7113) were measured, and the rate of change in water absorption and tensile elastic modulus before and after treatment was calculated. In addition, the storage elastic modulus at 0 ° C. and 40 ° C. measured at a frequency of 10 Hz and a heating rate of 10 ° C./min was measured using RS instruments manufactured by TA instruments, and the change rate was calculated.

[Reference example]
[Production of Polyether Ester Block Copolymer (A-1)]
902 parts of terephthalic acid, 758 parts of 1,4-butanediol and 637 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400, together with 3 parts of titanium tetrabutoxide and 3 parts of trimellitic anhydride, a helical ribbon stirring blade Was charged at 225 ° C. for 2 hours and 30 minutes, and 95% of the theoretical amount of methanol was distilled out of the system. After adding 0.5 parts of “Irganox” 1330 (Hindered Phenolic Antioxidant manufactured by Ciba Geigy) to the reaction mixture, the temperature was raised to 245 ° C., and then the pressure in the system was increased to 27 Pa over 50 minutes. The polymerization was carried out for 1 hour and 50 minutes under the reduced pressure. The obtained polymer was discharged into water in the form of strands and pelletized by cutting. The obtained pellets were charged into a rotatable reaction vessel, the pressure inside the system was reduced to 27 Pa, and heated while rotating at 170 to 180 ° C. to carry out solid phase polycondensation. The obtained polyetherester block copolymer (A-1) had a hardness of 55D, a melting point of 208 ° C., and a melt flow rate of 230 g at 8.0 g / 10 min.

[Production of Polyether Ester Block Copolymer (A-2)]
902 parts of terephthalic acid, 758 parts of 1,4-butanediol and 637 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400, together with 3 parts of titanium tetrabutoxide and 3 parts of trimellitic anhydride, a helical ribbon stirring blade Was charged at 225 ° C. for 2 hours and 30 minutes, and 95% of the theoretical amount of methanol was distilled out of the system. After adding 0.5 parts of “Irganox” 1330 (Hindered Phenolic Antioxidant manufactured by Ciba Geigy Co.) to the reaction mixture, the temperature was raised to 245 ° C., and then the pressure in the system was increased to 27 Pa over 50 minutes. The polymerization was carried out for 1 hour and 50 minutes under the reduced pressure. The obtained polymer was discharged into water in the form of strands and pelletized by cutting. The obtained pellets were charged into a rotatable reaction vessel, the pressure inside the system was reduced to 27 Pa, and heated while rotating at 170 to 180 ° C. to carry out solid phase polycondensation. The obtained thermoplastic polyester block copolymer (A-2) had a hardness of 53D, a melting point of 203 ° C., and a melt flow rate of 230 g at 1.8 g / 10 min.

[Production of Polyether Ester Block Copolymer (A-3)]
1061 parts of terephthalic acid, 920 parts of 1,4-butanediol and 415 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400 together with 3 parts of titanium tetrabutoxide and 3 parts of trimellitic anhydride and a helical ribbon stirring blade Was charged at 225 ° C. for 2 hours and 30 minutes, and 95% of the theoretical amount of methanol was distilled out of the system. After adding 0.5 parts of “Irganox” 1330 (Hindered Phenolic Antioxidant manufactured by Ciba Geigy Co.) to the reaction mixture, the temperature was raised to 245 ° C., and then the pressure in the system was increased to 27 Pa over 50 minutes. The polymerization was carried out for 1 hour and 50 minutes under the reduced pressure. The obtained polymer was discharged into water in the form of strands and pelletized by cutting. The obtained pellets were charged into a rotatable reaction vessel, the pressure inside the system was reduced to 27 Pa, and heated while rotating at 170 to 180 ° C. to carry out solid phase polycondensation. The obtained polyetherester block copolymer (A-3) had a hardness of 63D, a melting point of 215 ° C., and a melt flow rate of 1.5 g / 10 min at 240 ° C.

[Production of Polyether Ester Block Copolymer (A-4)]
A helical ribbon impeller with 1149 parts of terephthalic acid, 966 parts of 1,4-butanediol and 297 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1000 together with 3 parts of titanium tetrabutoxide and 3 parts of trimellitic anhydride Was charged at 225 ° C. for 2 hours and 30 minutes, and 95% of the theoretical amount of methanol was distilled out of the system. After adding 0.5 parts of “Irganox” 1330 (Hindered Phenolic Antioxidant manufactured by Ciba Geigy Co.) to the reaction mixture, the temperature was raised to 245 ° C., and then the pressure in the system was increased to 27 Pa over 50 minutes. The polymerization was carried out for 1 hour and 50 minutes under the reduced pressure. The obtained polymer was discharged into water in the form of strands and pelletized by cutting. The obtained pellets were charged into a rotatable reaction vessel, the pressure inside the system was reduced to 27 Pa, and heated while rotating at 170 to 180 ° C. to carry out solid phase polycondensation. The resulting polyether ester block copolymer (A-4) had a hardness of 72D, a melting point of 216 ° C., and a melt flow rate of 14.0 g / 10 min at 240 ° C.

[Reinforcing agent (B-1)]
Polybutylene terephthalate resin, intrinsic viscosity 0.85, PBT resin “Toraycon” 1100S manufactured by Toray Industries, Inc. was used.
[Reinforcing agent (B-2)]
Polybutylene terephthalate resin, intrinsic viscosity 1.74, PBT resin “Toraycon” 1400S manufactured by Toray Industries, Inc. was used.
[Reinforcing agent (B-3)]
Polybutylene naphthalate resin, intrinsic viscosity 0.80, glass-filled PBT resin “Toraycon” 1101G30 manufactured by Toray Industries, Inc. was used.
[Reinforcing agent (B-4)]
Polybutylene naphthalate resin, intrinsic viscosity 0.80, PBN resin “TQB-OT” manufactured by Teijin Chemicals Ltd. was used.

  For comparison, polyamide 11 resin and polyamide 11 resin “Rilsan BMNO” manufactured by Arkema Co., Ltd. were used.

[Examples 1-7]
To the polyester block copolymers (A-1), (A-2), (A-3) and (A-4) obtained in Reference Examples, reinforcing agents (B-1), (B-2), (B-3) and (B-4) were mixed using a V-blender at the blending ratio (% by weight) shown in Table 1, and a twin screw extruder having a diameter of 45 mm and a triple thread type screw was used. The mixture was melt kneaded at 240 ° C. and pelletized.

  Table 1 shows the results of evaluating the isothermal crystallization time, the high-speed surface impact test, the melt viscosity, and the flexural modulus using these pellets.

  Table 1 also shows the results of molding from the above pellets using an injection molding machine and evaluating moldability and environmental stability.

[Comparative Examples 1 to 7]
At the blending ratio (% by weight) shown in Table 1, it was melt-kneaded and pelletized in the same manner as in Examples 1-7. The results of evaluating physical properties in the same manner as in Examples 1 to 7 are also shown in Table 1.

  As can be seen from the results in Table 1, the polyester block copolymer alone has a low flexural modulus (Comparative Examples 1-2). In addition, when the proportion of the polyester block copolymer is low or when the polyester block copolymer having a low proportion of the low-melting polymer segment is used, a high flexural modulus can be obtained, but the impact resistance at low temperature is improved. Inferior (Comparative Examples 3 to 6). On the other hand, polyamide 11 is excellent in flexural modulus, moldability, and impact resistance at low temperature, but has a large change in physical properties due to water absorption and temperature, and lacks environmental stability (Comparative Example). 7).

  Based on the above results, the polyester block copolymer resin compositions (Examples 1 to 7) comprising the composition of the present invention have moldability / rigidity (flexural modulus), impact resistance at low temperatures, and environmental stability. It turns out that it is excellent in.

  The polyester block copolymer resin composition and molded product of the present invention are effective for various molded products for automobiles, electronic / electric equipment, precision equipment, and general consumer goods, taking advantage of the above-described excellent properties, It is particularly suitable for automobile interiors and exteriors that require surface impact properties due to its thin thickness, and for electronic and electrical applications such as housings such as battery packs, binding bands, connector parts, and sports applications (for example, resin shuttlecocks, etc.).

Claims (3)

The low-melting-point crystalline polymer segment (a1) composed of crystalline aromatic polyester and the low-melting-point polymer segment (a2) composed of aliphatic polyether unit and / or aliphatic polyester unit, A resin composition comprising 50 to 80% by weight of a polyester block copolymer (A) having a polymer segment (a2) occupying 25 to 70% by weight and 20 to 50% by weight of a hard resin (B). In addition, a polyester block copolymer resin composition that further satisfies all the following conditions (1) to (4).
(1) Viscosity (Pa · s) measured at a measurement temperature of 260 ° C. and a shear rate of 20000 sec ⁻¹ measured according to JIS K7199 method is 40 or less. (2) Isothermal crystallization time is 1.0 min. (3) In a high-speed surface impact test measured according to the ASTM D3763 method, it shows ductile fracture under the conditions of a test speed of 10 m / s, a striker diameter of 1/2 inch, a test temperature of −30 ° C., and a fracture energy of 20 J or more (4 ) Bending elastic modulus at 23 ° C. measured according to ASTM D256 is 400 MPa or more The polyester block copolymer resin composition according to claim 1, wherein the hard resin (B) is polybutylene terephthalate and / or polybutylene naphthalate. The molded object formed by injection-molding the polyester block copolymer resin composition in any one of Claims 1-2.