JP2011102365A - Polyester elastomer resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester elastomer resin composition which is excellent in crystallinity though it has a low melting point, has flexibility, is easily fabricated into a binder fiber or a molded article and can be suitably used in various adhesive applications. <P>SOLUTION: The polyester elastomer resin composition contains a polyester which includes a dicarboxylic acid component mainly composed of terephthalic acid and a diol component mainly composed of 1, 6-hexanediol, as a hard segment and polyalkylene glycol having 500-5,000 average molecular weight, as a soft segment. The polyester elastomer resin composition contains 5-50 mass% soft segment, has 100-150°C melting point, contains 0.01-3.0 mass% crystal nucleating agent and has 20-60 Shore hardness. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyester elastomer resin composition that has high crystallinity despite its low melting point, has flexibility, and is excellent in operability and productivity.

  Polyester elastomer has thermoplastic properties in addition to excellent mechanical properties such as flexibility, elastic recovery, strength, impact resistance, etc., and can be easily molded. Widely used in automotive parts, electrical parts, molded products, films and fibers.

  However, polybutylene terephthalate is used for the hard segment, which is generally used as a polyester elastomer, and an aliphatic polyether unit such as poly (alkylene oxide) glycol and / or an aliphatic polyester unit such as polylactone is used for the soft segment. Since the polyester elastomer (Patent Document 1) using the material has a low melting point of 160 ° C., which is higher than the melting point of polyethylene, which is the most common as a molding material, is 130 ° C., an excessive energy cost is required for molding. Become.

  In addition, polyester elastomers that use aliphatic polyether units such as poly (alkylene oxide) glycol and / or aliphatic polyester units such as polylactone in the soft segment generally have a significant viscosity decrease due to thermal decomposition. The provision of thermal stability is one of the problems.

  In addition, polyester resins have a high demand for those having a low melting point, and are used for binder fibers, adhesives, and the like. For such applications, a copolyester is generally used. For example, Patent Document 2 shows a binder polymer having a low melting point near 130 ° C. and excellent dimensional stability as a suitable polymer. Copolyesters that enable this have been proposed.

  However, since these polymers lack flexibility, when used as binder fibers or adhesives, the strength at the bonding point is low, and the adhesive strength may be inferior.

Japanese Patent Laid-Open No. 06-329888 JP 2008-248218 A

  The present invention solves the above-mentioned problems and has excellent crystallinity despite its low melting point, excellent flexibility and thermal stability, and can be easily processed into a binder fiber or a molded product. Therefore, an object of the present invention is to provide a polyester elastomer resin composition that can be suitably used for various adhesive applications.

The present inventor has reached the present invention as a result of studies to solve the above-mentioned problems.
That is, the present invention comprises a hard segment comprising a dicarboxylic acid component comprising terephthalic acid as a main component and a diol component comprising 1,6-hexanediol as a main component, and a polyalkylene glycol having an average molecular weight of 500 to 5000 as a soft segment A polyester elastomer resin composition having a soft segment content of 5 to 50% by mass, a melting point of 100 to 150 ° C., a crystal nucleating agent of 0.01 to 3.0% by mass, and a Shore hardness of The gist of the polyester elastomer resin composition is 20 to 60.

  The polyester elastomer resin composition of the present invention is excellent in crystallinity and thermal stability despite its low melting point, and therefore has excellent moldability and cost performance as a molding material, and can be obtained with good operability. It is. Furthermore, since it has a softness | flexibility, when it uses as a binder fiber or an adhesive agent, the strength at an adhesion point becomes high and can be used suitably for various adhesion | attachment uses.

It is an example of the DSC curve which shows the temperature-fall crystallization calculated | required from DSC of the polyester elastomer resin composition in this invention.

Hereinafter, the present invention will be described in detail.
The polyester elastomer resin composition of the present invention comprises a polyester hard segment and a polyalkylene glycol soft segment.

  In the hard segment polyester, the dicarboxylic acid component has terephthalic acid as the main component, and the diol component has 1,6-hexanediol as the main component.

  As the dicarboxylic acid component, terephthalic acid (TPA) is preferably 60 mol% or more, and more preferably 80 mol% or more. If the TPA is less than 60 mol%, the melting point of the polymer falls outside the range of the present invention, and the crystallinity tends to decrease, which is not preferable.

  In addition, as a copolymerization component other than TPA, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid are within the range that does not impair the effect. Acid, saturated aliphatic dicarboxylic acid exemplified by 1,4-cyclohexanedicarboxylic acid, dimer acid and the like, or ester-forming derivatives thereof, unsaturated aliphatic dicarboxylic acid exemplified by fumaric acid, maleic acid, itaconic acid and the like Aromatic dicarboxylic acids exemplified by these ester-forming derivatives, phthalic acid, isophthalic acid, 5- (alkali metal) sulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like These ester-forming derivatives are mentioned. Examples of polyvalent carboxylic acids other than dicarboxylic acids include butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, 3,4,3 ′, 4′-biphenyltetracarboxylic acid, and ester-forming derivatives thereof. Can be mentioned.

Examples of the hydroxycarboxylic acid include lactic acid, citric acid, malic acid, hydroxyacetic acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, and ester-forming derivatives thereof.
Examples of ester-forming derivatives of polyvalent carboxylic acids or hydroxycarboxylic acids include these alkyl esters, acid chlorides, acid anhydrides, and the like.

  As the diol component, 1,6-hexanediol (hereinafter referred to as HD) is preferably 60 mol% or more, and more preferably 80 mol% or more. When the HD is less than 60 mol%, the melting point of the polymer is outside the range of the present invention, and the crystallinity tends to be lowered, which is not preferable.

  In addition, as a copolymer component other than HD, the diol component includes ethylene glycol (hereinafter referred to as EG), 1,4-butanediol (hereinafter referred to as BD), and 1 as long as the characteristics are not impaired. , 2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanediol, 1, Aliphatic glycols exemplified by 4-cyclohexanedimethanol, polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol and the like, hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy) benzene, Bisphenol A 2,5-naphthalene diol, an aromatic glycol exemplified such as glycol ethylene oxide is added to these glycols.

Examples of the polyhydric alcohol other than glycol include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol, hexanetriol and the like.
Examples of the cyclic ester include ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolide, and lactide.

  As the polyalkylene glycol of the soft segment, a polyalkylene glycol having a molecular weight of 500 to 5000, preferably 1000 to 3000 is used, and among them, polytetramethylene glycol (PTMG) and polyethylene glycol (PEG) are preferably used.

  When the average molecular weight of the polyalkylene glycol is less than 500, sufficient elastic properties cannot be obtained and the Shore hardness is high. On the other hand, if it exceeds 5000, the compatibility with the polyester forming the hard segment will be poor, a uniform polymer will not be obtained, and the elastic properties will also deteriorate.

  The proportion of the soft segment is 5 to 50% by mass, preferably 10 to 40% by mass, and more preferably 15 to 35% by mass. When the proportion of the soft segment is less than 5% by mass, sufficient adhesion and elastic properties cannot be obtained, and the Shore hardness is high. On the other hand, if it exceeds 50% by mass, some of the hard segments cannot be completely copolymerized and the polymer has a low melt viscosity, resulting in poor workability in the polymer dispensing step and subsequent processing steps.

  The polyester elastomer resin composition of the present invention contains 0.1 to 2 hindered phenolic antioxidants in order to improve thermal stability over time, which is a problem when polyalkylene glycol is used as a soft segment. The content is preferably 0.0% by mass, and more preferably 0.2 to 1.0% by mass. When the content of the hindered phenolic antioxidant is less than 0.1% by mass, the thermal stability of the polyester elastomer resin composition is not improved, and after a long period of time, the intrinsic viscosity is lowered and the color tone after molding is likely to occur. Become. On the other hand, if the content exceeds 2.0% by mass, the polycondensation reaction rate decreases and the color tone and transparency of the polyester elastomer resin composition tend to deteriorate.

  As the hindered phenol antioxidant, 2,6-di-t-butyl-4-methylphenol, n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) Propionate, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 4, 4′-butylidenebis- (3-methyl-6-tert-butylphenol), triethylene glycol-bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 3,9-bis { 2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1′-dimethylethyl} -2,4 , 10-tetraoxaspiro [5,5] undecane, etc. are used, but tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane in terms of effect and cost Is preferred.

  The melting point of the polyester elastomer resin composition of the present invention is 100 to 150 ° C, preferably 110 to 140 ° C, more preferably 115 to 135 ° C. When the melting point of the polyester elastomer resin composition is less than 100 ° C., the thermal stability is deteriorated, so that the operability and productivity are also lowered. On the other hand, if the melting point exceeds 150 ° C., heat treatment at a high temperature is required when used for molding and bonding, which is disadvantageous in cost.

The polyester elastomer resin composition of the present invention has a Shore hardness of 20 to 60, and preferably 30 to 55. If the Shore hardness is less than 20, the mechanical strength of the resulting molded product or fiber product will be low, while if it exceeds 60, the flexibility will be inferior.
The Shore hardness in the present invention is measured using a type D durometer according to ASTM D-2240.

  The polyester elastomer resin composition of the present invention has crystallinity due to the composition as described above, but improves the crystallization rate during cooling by containing a crystal nucleating agent. Can do. And it is preferable to satisfy the formula (1) described later.

  The polyester elastomer resin composition of the present invention contains 0.01 to 3.0% by mass of a crystal nucleating agent, preferably 0.1 to 1.0% by mass. When the content of the crystal nucleating agent in the polyester elastomer resin composition is less than 0.01% by mass, the crystallization rate at the time of cooling cannot be improved, and the polyester elastomer resin composition is described later in formula (1). It becomes difficult to satisfy. On the other hand, when the content exceeds 3.0% by mass, the content of the crystal nucleating agent is excessively increased, and the polymerizability and workability are deteriorated. It will make it worse.

As the crystal nucleating agent, organic fine particles, organic compounds composed of polyolefin, sulfates, and the like can be used. Of these, organic compounds composed of polyolefin are preferred. As the inorganic fine particles, those mainly composed of silicon oxide such as talc are preferable, and inorganic fine particles having an average particle size of 3.0 μm or less or a specific surface area of 15 m ² / g or more are preferably used.

  In addition, the organic compound comprising polyolefin is not particularly limited in shape because it melts in the reaction system. For example, a chip-like one having a particle size of about 2 mm or a wax-like one having a particle size of several μm is used. Can be mentioned. Of these, wax-like ones are preferred.

Examples of polyolefins include olefin homopolymers such as polyethylene, polypropylene, poly-1-butene, polymethylpentene, and polymethylbutene, and propylene / ethylene random copolymers. Polyethylene, polypropylene, poly-1- Butene and propylene / ethylene random copolymers are particularly preferred. When the polyolefin is a polyolefin obtained from an olefin having 3 or more carbon atoms, it may be an isotactic polymer or a syndiotactic polymer.
The polyolefin may be obtained by any production method and catalyst. For example, not only polyolefin obtained by a conventional Ziegler-Natta type catalyst but also polyolefin obtained by a metallocene catalyst is suitable. Can be used for Such polyolefin may be used independently and may be used in combination of 2 or more type.

  Examples of the sulfate contained as a crystal nucleating agent include lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, barium sulfate, calcium sulfate, and aluminum sulfate. Sodium and magnesium sulfate are preferred.

In the polyester elastomer resin composition of the present invention, the DSC curve indicating the temperature-falling crystallization obtained from DSC preferably satisfies the following formula (1), and it is particularly preferable that b / a ≧ 0.05. On the other hand, the larger b / a, the better the crystallinity when the temperature is lowered. However, in order to achieve the intended effect of the present invention, b / a is preferably 0.5 or less.
b / a ≧ 0.03 (mW / mg · ° C.) (1)

  The DSC curve showing the temperature drop crystallization determined from the melting point of the polyester elastomer resin composition and DSC in the present invention is a temperature range of −20 ° C. in a nitrogen stream using a Perkin Elmer differential scanning calorimeter (Diamond DSC). It is measured at ˜250 ° C., temperature rising (falling temperature) rate of 20 ° C./min, sample amount of 2 mg.

  Said b / a is calculated | required from the DSC curve which shows the temperature-fall crystallization calculated | required from DSC. As shown in FIG. 1, a is the temperature A1 (° C.) of the intersection of the tangent line and the base line with the maximum inclination in the DSC curve indicating the temperature-falling crystallization, the tangent line and the base line with the minimum inclination. Is the difference (A1−A2) from the temperature A2 (° C.) at the intersection of the two, and b is the difference (B1−B2) between the baseline heat amount B1 (mW) and the peak top heat amount B2 (mW) at the peak top temperature. ) Divided by the sample amount (mg).

  b / a is an index representing the crystallinity when the temperature is lowered, and the higher the b / a value, the faster the crystallization rate, and vice versa, the closer to 0, the slower the crystallization rate. When b / a is less than 0.03 (mW / mg · ° C.), the crystallization rate is slow, and therefore, blocking tends to occur in polyester chip formation, storage / transport, and drying steps. Further, when the fiber is made, if the heat treatment temperature in the drawing / heat treatment step is raised, the fiber is melted and glued.

  Said b / a can be set to the range prescribed | regulated by this invention by adjusting the copolymerization composition of a polyester elastomer resin composition, and content of a crystal nucleating agent.

  Moreover, it is preferable that the polyester elastomer resin composition of the present invention contains 0.05 to 1.0% by mass of a phosphorus-based antioxidant, and more preferably 0.07 to 0.7% by mass. Is preferred. It is preferable to use a phosphorus-based antioxidant together with the above-mentioned hindered phenol-based antioxidant because the thermal stability of the resin composition can be further improved. When the content of the phosphorus-based antioxidant is less than 0.05% by mass of the resin composition, the effect of improving the thermal stability becomes poor. On the other hand, when the content exceeds 1.0% by mass, it is not preferable because it tends to cause a decrease in the polycondensation reaction rate and coloring of the polyester elastomer resin composition.

  Examples of phosphorus antioxidants include triphenyl phosphite, trioctadecyl phosphite, trisnonylphenyl phosphite, trilauryl trithiophosphite, bis (2,4-di-t-butylphenyl) pentaerythritol- Diphosphite, bis (3-methyl-1,5-di-t-butylphenyl) pentaerythritol-diphosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-t- Phosphite antioxidants such as butylphenyl) pentaerythritol-diphenylphosphite and diethyl [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, bis (3,5- And phosphonic acid ester-based antioxidants such as di-t-butyl-4-hydroxybenzylphosphonic acid ethyl) calcium.

  The polyester elastomer resin composition of the present invention preferably has an intrinsic viscosity of 0.5 or more. When the intrinsic viscosity is less than 0.5, various physical, mechanical, and chemical properties are inferior, and spinnability is impaired when the fiber is used. On the other hand, even if the intrinsic viscosity is too high, the melt viscosity becomes high, making extrusion difficult, and when making fibers, if the spinning temperature is raised to lower the melt viscosity, the thermal decomposition of the polyester becomes significant. Since spinning becomes difficult, it is preferable that it is 1.5 or less practically.

  In the polyester elastomer resin composition of the present invention, a color tone improver such as a cobalt compound, a fluorescent whitening agent, a dye, a matting agent such as titanium dioxide, a plasticizer, a pigment, Various additives such as antistatic agents, flame retardants, and dyeing agents may be added alone or in combination of two or more.

Next, the manufacturing method of the polyester elastomer resin composition of this invention is demonstrated using an example. The polyester elastomer resin composition of the present invention is produced by subjecting a dicarboxylic acid component, a diol component, and a polyalkylene glycol to an esterification reaction or a transesterification reaction, and performing a polycondensation reaction to produce the polyester elastomer resin composition of the present invention. Can do.
Specifically, the polycondensation reaction is usually performed under a reduced pressure of about 0.01 to 10 hPa at a temperature of 220 to 280 ° C. until a product having a predetermined intrinsic viscosity is obtained. The polycondensation reaction is carried out in the presence of a catalyst. As a catalyst, conventionally used metals such as antimony, germanium, tin, titanium, zinc, aluminum, magnesium, potassium, calcium, sodium, manganese and cobalt are commonly used. In addition to the compounds, organic sulfonic acid compounds such as sulfosalicylic acid and o-sulfobenzoic anhydride can be used.
The crystal nucleating agent and various additives (which can be used within a range not impairing the effects of the present invention) may be added at any stage during the production of the polyester in the form of powder or diol slurry. For example, it may be added at the time of esterification or transesterification, or may be added at the stage of polycondensation reaction.
When the polyester reaches a predetermined intrinsic viscosity in the polycondensation reaction, it is discharged into a strand shape, cooled, and cut into chips.

Next, the present invention will be specifically described using examples.
The measurement and evaluation methods for various characteristic values in the examples are as follows.
(A) Intrinsic viscosity [η]
Measurement was carried out based on a conventional method under the conditions of a sample concentration of 0.5% by mass and a temperature of 20 ° C. using an equal mass mixture of phenol and ethane tetrachloride as a solvent.
(B) Melting point, DSC curve showing cooling crystallization determined from DSC Measured by the method described above.
(C) Polymer composition The obtained polyester elastomer resin composition was dissolved in a mixed solvent having a volume ratio of 1/20 of deuterated hexafluoroisopropanol and deuterated chloroform, and the mixture was applied to an LA-400 type NMR apparatus manufactured by JEOL Ltd. 1H-NMR was measured and obtained from the integral intensity of the proton peak of each copolymer component in the obtained chart.
(D) Shore hardness It measured by the said method.
(E) Thermal stability The obtained polyester elastomer resin composition was treated under nitrogen at 250 ° C. for 1 hour, and the difference in intrinsic viscosity before and after the treatment was within 0.05, and over 0.05 X.
(F) Operability [chip conversion]
When a polyester elastomer resin composition is made into chips with an AUTOMATIK USG-600 type cutter, due to the occurrence of a fusion of two or more chips due to winding of polyester around a feed roller or cutter blade or fusion between strands, etc. If the operation of the cutter is interrupted x, problems such as fusing will occur, and if it is interrupted from time to time, it will be △, if there is a problem such as fusing, insert without interrupting the operation of the cutter The case where it was able to be made into a chip without causing a problem due to fusion was marked as ◎.
[Chip blocking]
When the chip storage / transport and drying process produces a block-like lump that does not collapse or a fused product on the wall surface, there is a block-like lump or deposit on the wall surface, and direct impact is applied with a hammer, etc. △ When it is resolved by a certain amount of force, there is a block-like lump or deposit on the wall, but it can be resolved by touching with a hand or applying an impact to the wall with a hammer etc. ○, when no block lump or fusion to the wall surface occurred at all.

Example 1
To the esterification can, 23 kg of TPA, 22 kg of HD, 15 kg of PTMG with an average molecular weight of 1000, 15 g of polyethylene wax, 10 g of monobutyltin hydroxyoxide are supplied, and the reaction is made transparent at a temperature of 250 ° C. and normal pressure. An esterification reaction product was obtained. This reaction product was transferred to a polycondensation reaction vessel, and 1.1 kg of EG solution containing 4% by mass of tetrabutyl titanate as a polycondensation catalyst was charged into the polycondensation reaction vessel, and the pressure in the reactor was adjusted to a temperature of 250 ° C. The amount was gradually decreased, and after 70 minutes, the pressure was reduced to 1.2 hPa or less. The polycondensation reaction was carried out for about 8 hours with stirring under these conditions, and the strands were discharged in a conventional manner to form chips.

Example 2
A polycondensation reaction was carried out in the same manner as in Example 1 except that the content of PTMG in the resin composition was variously changed as shown in Table 1, and was discharged into a strand by a conventional method to form chips.

Example 3
In an esterification reaction can, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane (Irganox-1010 manufactured by Ciba Specialty Inc.) as a hindered phenolic antioxidant A polycondensation reaction was carried out in the same manner as in Example 1 except that 100 g was supplied, and the strands were discharged in a conventional manner to form chips.

Examples 4-7, Comparative Examples 1-6
The polycondensation reaction was performed in the same manner as in Example 3 except that the content of PTMG, the content of crystal nucleating agent, and the content of antioxidant in the resin composition were changed to the values shown in Table 1. Then, it was discharged into a strand shape by a conventional method to form a chip.

Example 8
To the esterification reactor, 22.3 kg of TPA, 0.7 kg of IPA, 22 kg of HD, 15 kg of PTMG with an average molecular weight of 1000, 15 g of polyethylene wax, 10 g of monobutyltin hydroxyoxide, temperature 250 ° C., normal pressure The esterification reaction product was obtained by making the reaction transparent under the conditions of This reaction product was transferred to a polycondensation reaction vessel, and 1.1 kg of EG solution containing 4% by mass of tetrabutyl titanate as a polycondensation catalyst was charged into the polycondensation reaction vessel, and the pressure in the reactor was adjusted to a temperature of 250 ° C. The amount was gradually decreased, and after 70 minutes, the pressure was reduced to 1.2 hPa or less. The polycondensation reaction was carried out for about 8 hours with stirring under these conditions, and the strands were discharged in a conventional manner to form chips.

Example 9
To the esterification can, 23 kg of TPA, 22 kg of HD, 1 kg of EG, 15 kg of PTMG with an average molecular weight of 1000, 15 g of polyethylene wax, 10 g of monobutyltin hydroxyoxide are supplied, and the reaction is conducted at a temperature of 250 ° C. and normal pressure Thus, a clarified esterification reaction product was obtained. This reaction product was transferred to a polycondensation reaction vessel, and 1.1 kg of EG solution containing 4% by mass of tetrabutyl titanate as a polycondensation catalyst was charged into the polycondensation reaction vessel, and the pressure in the reactor was adjusted to a temperature of 250 ° C. The amount was gradually decreased, and after 70 minutes, the pressure was reduced to 1.2 hPa or less. The polycondensation reaction was carried out for about 8 hours with stirring under these conditions, and the strands were discharged in a conventional manner to form chips.

Comparative Example 7
A polycondensation reaction was performed in the same manner as in Example 8 except that the amount of TPA and IP supplied to the esterification reactor was changed to 11.5 kg of TPA and 11.5 kg of IPA. did.

Comparative Example 8
A polycondensation reaction was carried out in the same manner as in Example 9 except that HD and EG supplied to the esterification reactor were changed to HD 10 kg and EG 6.5 kg.

  Table 1 shows the characteristic values of the resin compositions obtained in Examples 1 to 9 and Comparative Examples 1 to 8 and the evaluation results of the operability during chip formation.

As is clear from Table 1, the polyester elastomer resin compositions of Examples 1 to 9 had a low melting point, excellent flexibility and crystallinity, and good operability in the chip forming process. Among them, the polyester elastomer resin compositions of Examples 3 to 9 were excellent in thermal stability.
Since the resin composition of Comparative Example 1 had a low molecular weight of polyalkylene glycol, the resin composition of Comparative Example 3 had a high hardness and poor flexibility due to a low content of polyalkylene glycol. . Since the resin composition of Comparative Example 2 had a high molecular weight of polyalkylene glycol, the resin composition of Comparative Example 4 had a high polyalkylene glycol content, so both were poorly compatible and b / a was low. The resin composition of Comparative Example 4 had an even lower melting point and was inferior in operability in the chip forming process. Since the resin composition of Comparative Example 5 did not have a crystal nucleating agent, b / a was low, and the operability in the chip-forming step was poor. Since the resin composition of Comparative Example 6 contained too much content of the crystal nucleating agent, the polymerizability was poor and the operability in the chip forming process was poor. Since the resin compositions of Comparative Examples 7 and 8 were amorphous, had no melting point, and had a low glass transition point, solidification at room temperature was difficult, and the operability in the chip forming process was poor. there were.

Claims (3)

Polyester elastomer resin composition comprising a hard segment made of a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing 1,6-hexanediol as a main component, and a polyalkylene glycol having an average molecular weight of 500 to 5000 as a soft segment. The soft segment occupies 5 to 50% by mass, the melting point is 100 to 150 ° C., the crystal nucleating agent is 0.01 to 3.0% by mass, and the Shore hardness is 20 to 60. A polyester elastomer resin composition. The polyester elastomer resin composition according to claim 1, wherein a DSC curve showing temperature-fall crystallization determined from DSC satisfies the following formula (1).
b / a ≧ 0.03 (mW / mg · ° C.) (1)
Note that a is the temperature A1 (° C.) of the intersection between the tangent line and the baseline having the maximum inclination in the DSC curve indicating the temperature-falling crystallization, and the temperature A2 (° C.) of the intersection of the tangent line and the baseline having the minimum inclination. B) is the difference (B1-B2) between the baseline heat quantity B1 (mW) and the peak top heat quantity B2 (mW) at the peak top temperature (mg) The value divided by. The polyester elastomer resin composition of Claim 1 or 2 which contains 0.1-2.0 mass% of hindered phenolic antioxidant in a resin composition.