JP5419016B2 - Thermoplastic polyester elastomer resin composition and molded article comprising the same - Google Patents

Description

  The present invention relates to a thermoplastic elastomer resin composition that is flexible, elastic, excellent in bending fatigue, and excellent in injection molding, extrusion molding, and blow molding, and a molded body comprising the same.

  Thermoplastic polyester elastomers have excellent mechanical properties such as strength, impact resistance, elastic recovery, flexibility, and low and high temperature properties, and are thermoplastic and easy to mold. Widely used in fields such as parts and consumer goods.

  Injection molding, extrusion molding, blow molding, and the like are used as molding methods for thermoplastic polyester elastomers, but different material properties are given due to differences in each molding processing method. For example, in injection molding, the molding cycle is shortened and the dimensional accuracy is improved by rapid solidification. In extrusion molding and blow molding, in consideration of the formability at the time of melting, material design is performed in which the melt elasticity is increased and the solidification rate is decreased.

  For example, blow molding and extrusion molding are used for molded articles such as cover boots, air ducts, and fuel tubes of constant velocity joint driving devices. Among them, a cover boot of a constant velocity joint drive device for an automobile is an application in which a thermoplastic polyester elastomer is widely used, and press blow molding is generally used. However, in addition to press blow molding, injection blow molding, which has both injection molding and blow molding methods, is being studied, but because the material design is different due to the difference in the molding process described above, injection molding and blow molding are used. There is a problem that there is no material having suitable characteristics and a material satisfying moldability cannot be obtained.

  Accordingly, various studies have been made in order to improve moldability. For example, a modification for a polyester resin containing a reactive compound containing a glycidyl group and / or an isocyanate group and having a weight average molecular weight of 200 to 500,000. Of a modified polyester resin containing a small amount of a polyolefin resin or a polyamide resin in a polyester resin by bringing a granule of the polyester resin into contact with the polyolefin resin or the polyamide resin under flow conditions (for example, see Patent Document 1) A thermoplastic elastomer resin composition comprising a production method (for example, see Patent Document 2), and a thermoplastic elastomer having a melting point of 180 to 220 ° C and a thermoplastic elastomer having a melting point 20 to 55 ° C lower than the melting point of the thermoplastic elastomer ( For example, see Patent Document 3).

  However, with these conventional technologies, the molding technology has not been sufficiently improved, and it is difficult to achieve both shrinkage during injection molding, blow moldability during blow molding, and bending fatigue properties. Met.

JP 2005-272680 A JP 2006-152315 A JP 2010-18697 A

  An object of the present invention is to solve the above-described problems in the prior art, and the object of the present invention is to be flexible, elastic, excellent in bending fatigue, and excellent in injection molding, extrusion molding, and blow molding. Another object of the present invention is to provide a thermoplastic polyester elastomer resin composition and a molded body using the same.

  As a result of diligent studies to achieve the above object, the present inventors have formulated a thermoplastic polyester elastomer in combination with a polyolefin resin, a glycidyl group-modified polyolefin resin, and a crystal nucleating agent, and a melt flow at a predetermined temperature. The inventors have found that the above object can be effectively achieved by making the rate satisfy a specific range, and have reached the present invention.

That is, in order to achieve the above object, according to the present invention, 0.1 to 25 parts by weight of polyethylene (B) with respect to 100 parts by weight of thermoplastic polyester elastomer (A) subjected to solid-phase polycondensation after melt polycondensation. And 0.1 to 15 parts by weight of a glycidyl group-modified polyolefin resin (C) and 0.01 to 5.0 parts by weight of a crystal nucleating agent (D), and a temperature determined by the following formula (1) A thermoplastic polyester elastomer resin having a melt flow rate of 1.0 g / 10 min or more and 8.0 g / 10 min or less in accordance with ASTM D-1238 at To (° C.) in accordance with ASTM D-1238 a composition, a crystal nucleating agent (D) is talc, or a thermoplastic polyester elastomer resin composition is calcium carbonate.
To = R _(Tm) +20 (1)
(However, Tm is defined as the melting point of the thermoplastic polyester elastomer (A), and R _(Tm) is defined as a value obtained by rounding up Tm to 10)

In the thermoplastic polyester elastomer resin composition of the present invention,
The thermoplastic polyester elastomer (A) comprises 20 to 70% by weight of a high-melting crystalline polymer segment composed of crystalline aromatic polyester units, and 80 to 30% by weight of a low-melting polymer segment composed of aliphatic polyether units. A polyester block copolymer having as a main component,
The glycidyl group-modified polyolefin resin (C) is a terpolymer comprising an α-olefin, an α, β-unsaturated acid and a glycidyl ester of an α, β-unsaturated acid ,
Before Symbol melt flow rate is 1. 0 g / 10 min or more and 5.0 g / 10 min or less,
However, both are preferable conditions, and by applying these conditions, it can be expected to obtain a more excellent effect.

  The molded article of the present invention is characterized in that the thermoplastic polyester elastomer resin composition is molded.

  According to the present invention, there is provided a thermoplastic polyester elastomer resin composition that is flexible and elastic, has excellent bending fatigue properties, and has excellent processability in various molding methods such as injection molding, extrusion molding and blow molding, and the like. A molded body can be obtained.

  Hereinafter, the present invention will be described in detail.

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

  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. Acid, diphenoxyethane dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 5-sulfoisophthalic acid, sodium 3-sulfoisophthalate and the like. 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.

  Specific examples of the diol include diols having a molecular weight of 400 or less, such as aliphatic diols such as 1,4-butanediol, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, Alicyclic diols such as 1,1-cyclohexanedimethanol, 1,4-dicyclohexanedimethanol, 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) phenyl] Cyclohex Aromatic diols such as 4,4′-dihydroxy-p-terphenyl and 4,4′-dihydroxy-p-quarterphenyl are preferred, and such diols are ester-forming derivatives such as acetylated, alkali metal salts. It can also be used in the form of

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

  A preferred example of such a high melting crystalline polymer segment is one comprising terephthalic acid or dimethyl terephthalate and polybutylene terephthalate units derived from 1,4-butanediol. The copolymerization amount of the high-melting crystalline polymer segment is usually 20 to 80% by weight, preferably 30 to 75% by weight.

  As the low-melting polymer segment 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 of the thermoplastic polyester elastomer (A) used in the present invention is usually 80 to 20% by weight, preferably 70 to 25% by weight.

  The thermoplastic polyester elastomer (A) used in the present invention is obtained by melt polycondensation. The melt polycondensation can be carried out by a known method. For example, a method in which 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 are transesterified in the presence of a catalyst and the resulting reaction product is polycondensed, an excess amount of the dicarboxylic acid A method in which the glycol and low-melting-point polymer segment components are esterified in the presence of a catalyst and the resulting reaction product is polycondensed, and a high-melting-point crystalline segment is prepared in advance, and a low-melting-point segment component is added to this. Then, any method such as a method of randomizing by transesterification may be used.

  The thermoplastic polyester elastomer (A) obtained by melt polycondensation is then finely divided. Fine graining may be performed by a cold cut method in which the thermoplastic polyester elastomer (A) taken out in a gut shape or a sheet shape is pelletized by a cutter, or by a hot cut method in which pelletization is performed without forming a gut shape or a sheet shape. . Moreover, you may grind | pulverize the thermoplastic polyester elastomer (A) taken out in the lump shape.

Molten thermoplastic polyester elastomer obtained in polycondensation (A) is then subjected to solid phase polycondensation. The solid phase polycondensation is carried out at a temperature at which the thermoplastic polyester elastomer (A) finely divided after melt polycondensation does not fuse, 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.

Polyolefin resin (B) used in the present invention is a port Riechiren. The compounding quantity of polyethylene (B) is 0.1-25 weight part with respect to 100 weight part of thermoplastic polyester elastomers (A), Preferably it is 0.5-20 weight part. If the amount is less than 0.1 parts by weight, the desired degree of improvement of the effect is small. If the amount exceeds 25 parts by weight, not only does the thermoplastic polyester elastomer (A) phase separate and the bending fatigue resistance deteriorates, but also the surface of the molded product is deteriorated. It causes delamination and impairs the appearance of the molded product.

The glycidyl group-modified polyolefin resin (C) used in the present invention is preferably a terpolymer comprising an α-olefin, an α, β-unsaturated acid and a glycidyl ester of an α, β-unsaturated acid. Examples of the α-olefin include ethylene, propylene, and butene-1, and among these, ethylene is preferably used. Examples of the α, β-unsaturated acid include vinyl esters such as vinyl ethers, vinyl acetate, and vinyl propionate, esters of acrylic acid and methacrylic acid such as methyl, ethyl, propyl, and butyl, acrylonitrile, and styrene. Among them, butyl acrylate and methyl methacrylate are preferably used. Furthermore, examples of the glycidyl ester of α, β-unsaturated acid include acrylic acid glycidyl ester, methacrylic acid glycidyl ester, and ethacrylic acid glycidyl ester. Among them, methacrylic acid glycidyl ester is preferably used. The blending amount of the glycidyl group-modified polyolefin resin (C) is 0.000 parts by weight with respect to 100 parts by weight of the thermoplastic polyester elastomer (A) . 1 to 15 parts by weight, preferably 1 to 10 parts by weight. Small improvement degree of the desired effect is less than 0.1 part by weight, it may turn bad if it exceeds 15 parts by weight oil resistance and grease resistance bending fatigue strength.

Crystal nucleating agent used in the present invention (D) is a non-melted during melt processing are those obtained for the cooling process becomes a crystal nucleus, talc, was or is calcium carbonate. The compounding amount of the crystal nucleating agent (D) is 0.01 to 5.0 parts by weight with respect to 100 parts by weight of the thermoplastic polyester elastomer (A). If the amount is less than 0.01 part by weight, the degree of improvement of the intended effect is small, and if it exceeds 5.0 parts by weight, the bending fatigue property is deteriorated.

The thermoplastic polyester elastomer resin composition in the present invention is
To = R _(Tm) +20 (1)
(However, Tm is defined as the melting point of the thermoplastic polyester elastomer (A), and R _(Tm) is defined as a value obtained by rounding up Tm to 10)
In temperature To determined by, in accordance with ASTM D-1238, melt flow rate measured under a load 2160g is, 1.0 g / 10 min or more, 8.0 g / 10 minutes or less, the good Mashiku 1.0 g / 10 min As mentioned above, it is important that it is 5.0 g / 10min or less .

  Furthermore, the thermoplastic elastomer resin composition of the present invention includes hindered phenol-based, phosphorus-based, sulfur-based, aromatic amine-based antioxidants, ultraviolet absorbers, and the like as long as the purpose is not impaired. Light stabilizers such as HALS, antistatic agents, lubricants such as metal soaps and fatty acid amides, polyethers such as poly (tetramethylene oxide) glycol and lubricants such as liquid polybutadiene, plasticizers, dyes, pigments, flame retardants, release agents Additives such as molds and reinforcing materials such as mica, glass flakes, clay, barium sulfate, glass beads, glass fibers, and carbon fibers can be added.

  The thermoplastic polyester elastomer resin composition of the present invention is flexible, rich in elasticity and excellent in bending fatigue, and can be applied to different molding methods such as injection molding, extrusion molding and blow molding. It is suitable for a molding method that combines a plurality of molding techniques such as injection blow molding that combines molding and blow molding.

  The effects of the present invention will be described below with reference to examples. 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)]
Measured according to JIS K7215 durometer D hardness.

[Melting point and crystallization temperature]
DSC Q100 manufactured by TA Instruments Inc. was used, and the melting point was measured by heating from room temperature to 240 ° C. at a rate of temperature increase of 10 ° C./min. Further, after holding at 240 ° C. for 3 minutes, the solution was cooled to 40 ° C. at a temperature decreasing rate of 10 ° C./min, and the crystallization temperature was measured.

[Bending fatigue]
From the sheet of 2 mm thickness obtained by press-molding each pellet of the resin composition for evaluation dried at 80 ° C. for 5 hours at a temperature of 250 ° C., a strip of length 80 mm × width 20 mm × thickness 2 mm was cut out. Using a dima bending fatigue testing machine manufactured by Seiki Seisakusho, the number of bendings until a crack was generated by measuring a stroke between 25 mm and 5 mm between chucks was measured in an atmosphere of 120 ° C.

[Melt flow rate]
From the melting point of the thermoplastic polyester elastomer (A), it was measured at a load To of 2160 g in accordance with ASTM D-1238 at the temperature To defined by the formula (1).
To = R _(Tm) +20 (1)
(However, Tm is defined as the melting point of the thermoplastic polyester elastomer (A), and R _(Tm) is defined as a value obtained by rounding up Tm to 10)

[Injection moldability]
As the injection moldability, a JIS No. 2 dumbbell test piece, a square plate of 75 mm length × 125 mm width × 2 mm thickness, a cylinder temperature of 240 ° C. and gold in each pellet of the resin composition for evaluation dried at 80 ° C. for 5 hours. Molding was performed at a mold temperature of 50 ° C., and the lower limit pressure at which the resin filled the mold was examined. The case where the lower limit pressure was less than 50 MPa was rated as ◯, and the case where the lower limit pressure was 50 MPa or more was rated as x.

[Blow moldability]
As the blow moldability, each pellet of the resin composition for evaluation dried at 80 ° C. for 5 hours was used by using a press blow molding machine manufactured by Osberger Co., Ltd., weight 70 g, peak outer diameter φ75 mm, valley outer diameter φ65 mm. A hollow pipe having a bellows portion of five ridges and four valleys with a wall thickness of 1.5 mm is molded at a temperature of 250 ° C., and the degree of formation of the edge shape of the ridge portion and the valley portion is visually observed. The case where the edge was not formed according to the dimensions of the mold or the case where the parison was deformed and the resin in the bellows part was folded was indicated as x.

[Reference Example 1]
[Method for producing thermoplastic polyester elastomer (A-1)]
44.4 parts of terephthalic acid, 38.6 parts of 1,4-butanediol and 43.9 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400, 0.04 part of titanium tetrabutoxide and mono-n-butyl -An esterification reaction was performed while charging 0.02 part of monohydroxytin oxide and a reaction vessel equipped with a helical ribbon type stirring blade, heating at 190 to 225 ° C for 3 hours, and allowing reaction water to flow out of the system. 0.2 part of tetra-n-butyl titanate was added to the reaction mixture, 0.05 part of “Irganox” 1098 (hindered phenol antioxidant manufactured by Ciba Geigy) was added, and the temperature was raised to 245 ° C. Then, the pressure in the system was reduced to 27 Pa over 50 minutes, and polymerization was performed for 1 hour and 50 minutes under the conditions. The obtained polymer was discharged into water in the form of strands and pelletized by cutting. The obtained thermoplastic polyester elastomer (A-1) had a hardness of 50D, a melting point of 203 ° C., and a melt flow rate of 18 g / 10 min.

[Method for producing thermoplastic polyester elastomer (A-2)]
The pellets of the thermoplastic polyester elastomer (A-1) were charged into a rotatable reaction vessel, the pressure in the system was reduced to 27 Pa, and heating was performed while rotating at 170 to 180 ° C. for 48 hours to perform solid phase polycondensation. . The obtained thermoplastic polyester elastomer (A-2) had a hardness of 50D, a melting point of 203 ° C., and a melt flow rate of 2.0 g / 10 min.

[Method for producing thermoplastic polyester elastomer (A-3)]
The pellets of thermoplastic polyester elastomer (A-1) were charged into a rotatable reaction vessel, the pressure in the system was reduced to 27 Pa, and heating was performed while rotating at 170 to 180 ° C. for 72 hours to perform solid phase polycondensation. . The obtained thermoplastic polyester elastomer (A-3) had a hardness of 50D, a melting point of 203 ° C., and a melt flow rate of 0.5 g / 10 min.

  The results of evaluating the physical properties of the melting point, crystallization temperature, flexural fatigue property, and melt flow rate of these thermoplastic polyester elastomer pellets A-1 to A-3 are shown in Table 1 as Reference Examples 1 to 3.

  Moreover, the following were prepared as polyolefin resin (B), glycidyl group modified polyolefin resin (C), and crystal nucleating agent (D).

[Polyolefin resin (B)]
The polyolefin resins used in the examples are as follows.
B-1: Novatec LF585M manufactured by Nippon Polyethylene
B-2: Hi-Zex 7000F manufactured by Prime Polymer

[Glycidyl group-modified polyolefin resin (C)]
C-1: Sumitomo Chemical Bond First 7M

[Crystal nucleating agent (D-1)]
Talc made by Takehara Chemical Industry

[Examples 1 to 4]
The thermoplastic polyester elastomer obtained in the Reference Example was mixed with a polyolefin resin, a glycidyl group-modified polyolefin resin, and a crystal nucleating agent using a V-blender at a blending ratio (parts by weight) shown in Table 1, and the diameter was 45 mm. Using a twin screw extruder having a triple thread type screw, it was melt-kneaded at 250 ° C. and pelletized.

[Comparative Examples 1-5]
The pellets of Comparative Examples 1 to 5 were obtained in the same manner as in Examples 1 to 4 with the blending ratio shown in Table 1.

  Using the pellets obtained in the above Examples and Comparative Examples, the melting point, the crystallization temperature, the bending fatigue property, and the physical properties of the melt flow rate were evaluated. As moldability, injection moldability and blow moldability were evaluated. The results are shown in Table 1.

  Based on the above results, the thermoplastic polyester elastomer resin compositions of the present invention shown in Examples 1 to 4 were flexible and elastic, excellent in bending fatigue resistance, and excellent in injection moldability and extrusion moldability. It was. On the other hand, the thermoplastic polyester elastomer resin composition of the comparative example does not satisfy all of them, whereas the comparative examples 1 and 4 having a large melt flow rate have poor bending fatigue properties and poor blow moldability. . On the other hand, Comparative Example 2 having a small melt flow rate has poor injection moldability. In Comparative Example 3 in which the olefin resin and the crystal nucleating agent were not blended, although blow molding was possible, it was necessary to increase the molding lower limit pressure for injection molding, and the injection moldability was poor. In Comparative Example 5 in which the olefin resin is not blended, the bending fatigue property is poor and the injection moldability is poor.

  The thermoplastic polyester elastomer resin composition of the present invention can be used as various molded articles for automobiles, electronic / electrical equipment, precision equipment, and general consumer goods, taking advantage of the above-described excellent properties, such as injection molding, extrusion molding, It is suitable for applications using a molding method that combines various molding methods such as blow molding.

Claims (5)

After melt polycondensation, solid phase polycondensation of thermoplastic polyester elastomer (A) 100 parts by weight, polyethylene (B) 0.1-25 parts by weight, glycidyl group-modified polyolefin resin (C) 0.1-15 parts by weight Parts, and 0.01 to 5.0 parts by weight of the crystal nucleating agent (D) at a temperature To (° C.) defined by the following formula (1), in accordance with ASTM D-1238, a load of 2160 g A thermoplastic polyester elastomer resin composition characterized in that the melt flow rate measured in (1) is 1.0 g / 10 min or more and 8.0 g / 10 min or less, wherein the crystal nucleating agent (D) is talc , Also, the thermoplastic polyester elastomer resin composition is calcium carbonate.
To = R _(Tm) +20 (1)
(However, Tm is defined as the melting point of the thermoplastic polyester elastomer (A), and R _(Tm) is defined as a value obtained by rounding up Tm to 10) The thermoplastic polyester elastomer (A) comprises 20 to 70% by weight of a high-melting crystalline polymer segment composed of crystalline aromatic polyester units, and 80 to 30% by weight of a low-melting polymer segment composed of aliphatic polyether units. The thermoplastic polyester elastomer resin composition according to claim 1, wherein the thermoplastic polyester elastomer resin composition is a polyester block copolymer having as a main component. The glycidyl group-modified polyolefin resin (C) is a terpolymer comprising an α-olefin, an α, β-unsaturated acid and a glycidyl ester of an α, β-unsaturated acid. 3. The thermoplastic polyester elastomer resin composition according to 2. The thermoplastic polyester elastomer resin composition according to any one of claims 1 to 3 , wherein the melt flow rate is 1.0 g / 10 min or more and 5.0 g / 10 min or less. A molded article obtained by molding the thermoplastic polyester elastomer resin composition according to any one of claims 1 to 4 .