Polyester elastomer resin and blow moldings

Abstract

The present invention is a polyester elastomer resin which can suppress inner surface roughness of a blow molded product caused by melt fracture during blow molding, and can achieve a balance between shape stabilization of a parison and a molded article and good molding properties such as reducing the degree of uneven thickness. The polyester elastomer resin contains, as constituent components, an acid component that includes an aromatic dicarboxylic acid and an alcohol component that contains an aliphatic and / or alicyclic diol and a polyalkylene glycol, and contains one or more types of trifunctional or higher component as a copolymer component at a quantity of 0-1.0 mol% relative to 100 mol% of all acid components or 100 mol% of all alcohol components. The polyalkylene glycol is a copolymer and has a number average molecular weight of 1000-4000. The polyester elastomer resin has a specific melt viscosity.

Description

[Technical field]

[0001] The present invention relates to a polyester elastomer resin suitable for blow molding, and more particularly to a polyester elastomer resin that has good shear rate dependency of melt viscosity characteristics and can achieve both inner surface smoothness and good moldability of a blow molded product. [Background technology]

[0002] Polyester elastomer blow moldings have been widely used as air duct products for automobiles to reduce weight compared to metal ducts. Recently, the demands on the shape of air duct products have been increasing in line with the trend to save space in engine rooms, and air duct products are being actively made to have more complex shapes, thinner walls, and longer lengths.

[0003] On the other hand, in order to reduce the number of parts and labor, quick connectors with a crimped structure are being used at the connections between air duct products and peripheral parts, and from the standpoint of sealing the connections, the smoothness of the inner surface of the molded product is an extremely important requirement.

[0004] As the shape of air duct products changes as mentioned above, it is becoming more difficult to ensure the smoothness of the inner surface of the molded product. In some cases, special blow molding methods such as 3D blow molding to create 3D shapes and suction blow molding, which uses forced suction to make the parison conform to the shape before blow molding, are used.

[0005] One of the reasons why good inner surface smoothness cannot be obtained is the melt fracture phenomenon that occurs due to the excessively high melt viscosity characteristics when passing through the die of the blow molding machine. The melt fracture phenomenon is caused by the disturbance of the resin flow due to the high shear stress applied to the molten resin. Therefore, in order to suppress the melt fracture phenomenon, it is necessary to reduce the melt viscosity when high shear stress is applied. In order to ensure inner surface smoothness, it is effective to increase the molding temperature or use a material with low viscosity, but on the other hand, molding defects such as drawdown of the parison, unstable shape during blowing, and tearing occur.

[0006] In view of the above, it is believed that a molding material that can be used for various blow moldings is suitable and preferable to have a high melt viscosity in the low shear rate region, which provides excellent resistance to drawdown and shape stability during blowing, and a low melt viscosity in the high shear rate region, i.e., a material whose melt viscosity has a high shear rate dependency.

[0007] Various attempts have been made to improve the melt viscosity characteristics of polyester elastomers, but there have been few effective studies on the shear rate dependency of melt viscosity. For example, Patent Document 1 discusses molding stability in blow molding of complex shapes, but does not go so far as to deeply discuss melt viscosity characteristics. Furthermore, Patent Document 2 considers resins that have excellent moldability not only for blow molding but also for injection blow molding, extrusion molding, and injection molding. However, it does not consider the shear rate dependency of melt viscosity, and it is believed that poor appearance (melt fracture phenomenon) occurs when high shear rates are applied. Furthermore, in Patent Document 3, the melt viscosity characteristics are improved by using a glycidyl group-modified olefin resin composition, but since the chain is extended by reaction with the polyester elastomer resin composition, it is considered that the shear rate dependency of the melt viscosity is small. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5066822 [Patent Document 2] JP 2017-043687 A [Patent Document 3] Patent No. 5786256 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a polyester elastomer resin which can suppress inner surface roughness of a blow-molded article caused by the melt fracture phenomenon in blow molding, which requires molding technology, and which can simultaneously achieve good moldability such as shape stabilization of the parison and molded article and reduction of thickness deviation. [Means for solving the problem]

[0010] The inventors have discovered that by appropriately combining tri- or higher functional components and block copolymers with number average molecular weights of 1,000 to 4,000, the melt viscosity can be effectively increased, and excellent melt viscosity characteristics that exhibit shear rate dependency that is suitable for various types of blow molding can be achieved, thereby arriving at the present invention. That is, the present invention is as follows. [1] A polyester elastomer resin comprising, as constituent components, an acid component containing an aromatic dicarboxylic acid, an aliphatic and / or alicyclic diol, and an alcohol component containing a polyalkylene glycol, the polyester elastomer resin contains, as a copolymerization component, 0 to 1.0 mol% of one or more trifunctional or higher functional components when the total acid components are 100 mol% and the total alcohol components are 100 mol%, the polyalkylene glycol is a block copolymer and has a number average molecular weight of 1,000 to 4,000; The melt viscosity characteristics measured with a capillary rheometer are 20°C higher than the melting point of the polyester elastomer resin and at a shear rate of 60-80 sec -1 The melt viscosity was measured at a temperature of 120 Pa·s at a shear rate of 6.08 sec -1A polyester elastomer resin having a melt viscosity of 6000 Pa·s or more. [2] The polyester elastomer resin according to [1], wherein the polyalkylene glycol is polyoxyethylene polyoxypropylene glycol. [3] The polyester elastomer resin according to [1], wherein the polyalkylene glycol is a block copolymer having a polyethylene glycol (PEG)-polypropylene glycol (PPG)-polyethylene glycol (PEG) structure. [4] The polyester elastomer resin according to [2] or [3], wherein the propylene glycol component contained in the polyester elastomer resin is 18 mass% or more in the polyester elastomer resin. [5] The polyester elastomer resin according to any one of [1] to [4], wherein the tri- or higher functional component is an acid component. [6] The polyester elastomer resin according to any one of [1] to [5], wherein the tri- or higher functional component is trimellitic acid. [7] A blow molded product comprising the polyester elastomer resin according to any one of [1] to [6]. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The polyester elastomer resin of the present invention is a polyester elastomer resin comprising an acid component containing an aromatic dicarboxylic acid, an aliphatic and / or alicyclic diol, and an alcohol component containing a polyalkylene glycol as constituent components, and is a resin comprising 0 to 1.0 mol % of one or more trifunctional or higher components as copolymerization components when the total acid components are 100 mol % and the total alcohol components are 100 mol %. The polyester elastomer resin of the present invention is a block copolymer in which a hard segment made of a polyester comprising an aromatic dicarboxylic acid and an aliphatic and / or alicyclic diol as constituent components is bonded to a soft segment comprising a polyalkylene glycol as a constituent component.

[0012] In the polyester elastomer resin of the present invention, the aromatic dicarboxylic acid is not particularly limited, but the main aromatic dicarboxylic acid is terephthalic acid, and other aromatic dicarboxylic acids are isophthalic acid, naphthalene-2,6-dicarboxylic acid, etc. Two or more of these acid components may be copolymerized. When the total acid components constituting the polyester elastomer resin is taken as 100 mol %, the aromatic dicarboxylic acid is preferably 70 mol % or more, more preferably 80 mol % or more, and even more preferably 90 mol % or more.

[0013] When the total acid components constituting the polyester elastomer resin are taken as 100 mol%, terephthalic acid is preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 85 mol% or more. In this case, it is also a preferred embodiment to contain 2 to 15 mol% of an aromatic dicarboxylic acid other than terephthalic acid, particularly isophthalic acid, from the viewpoint of melt viscosity characteristics. As the acid component constituting the polyester elastomer resin, an aliphatic dicarboxylic acid and / or an alicyclic dicarboxylic acid may also be used so long as it is 30 mol % or less.

[0014] In the polyester elastomer resin of the present invention, the aliphatic and / or alicyclic diol is not particularly limited, but is preferably an alkylene glycol having 2 to 8 carbon atoms. Specific examples include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, etc. Among these, in order to impart heat resistance, either ethylene glycol or 1,4-butanediol is preferable, and 1,4-butanediol is more preferable.

[0015] When the total alcohol components constituting the polyester elastomer resin is taken as 100 mol%, the aliphatic and / or alicyclic diols preferably account for 70 mol% or more and 98 mol% or less in total, more preferably 80 mol% or more and 97 mol% or less, and even more preferably 85 mol% or more and 97 mol% or less.

[0016] In the polyester elastomer resin of the present invention, the polyalkylene glycol has a number average molecular weight between 1000 and 4000. If the number average molecular weight is less than 1000, the blocking property of the polyester elastomer resin is low, and the low temperature characteristics required for a duct product are not satisfied. On the other hand, if it exceeds 4000, the compatibility of the hard segment and the soft segment is reduced, and the physical properties are deteriorated. A more preferable range of the number average molecular weight is 1000 to 3600, and even more preferably 1000 to 3500.

[0017] Furthermore, in the present invention, the polyalkylene glycol is a block copolymer. Common polyalkylene glycols include polyethylene glycol (PEG), polypropylene glycol (PEG), polytetramethylene glycol, polyhexamethylene oxide glycol, polyneopentyl glycol, etc. On the other hand, common block copolymers include polyoxyethylene polyoxypropylene glycol (copolymer of polyethylene glycol and polypropylene glycol), copolymer of polyneopentyl glycol and polyethylene glycol, and ethylene oxide addition polymer to polypropylene glycol terminal. These copolymers have the characteristics of each of the polyalkylene glycols that constitute them, and can obtain a composite effect that compensates for the shortcomings of each glycol.

[0018] For example, among polyoxyethylene polyoxypropylene glycols, those called Pluronic (registered trademark) type are common, and those having a polyethylene glycol (PEG)-polypropylene glycol (PPG)-polyethylene glycol (PEG) structure (including the above-mentioned ethylene oxide addition polymer to the polypropylene glycol terminal) are preferably used. By adopting a structure in which PEG exists at both ends of PPG, which has a methyl group in the side chain and a rigidified resin skeleton, it is possible to increase the reaction efficiency by compensating for the low reactivity of the secondary hydroxyl group terminal, which is a drawback of PPG, in addition to the shear rate-dependent effect of the melt viscosity due to the rigidification, which is a characteristic of PPG. A preferred block copolymer is polyoxyethylene polyoxypropylene glycol because of its availability, and a more preferred block copolymer is one having a polyethylene glycol (PEG)-polypropylene glycol (PPG)-polyethylene glycol (PEG) structure.

[0019] The propylene glycol component (oxypropylene unit) contained (copolymerized) in the polyester elastomer resin of the present invention is preferably 18% by mass or more in the polyester elastomer resin, more preferably 20% by mass or more. It is considered that the shear rate dependency of the melt viscosity is expressed due to the rigidification of the resin skeleton caused by the methyl group of propylene glycol, so the higher the propylene glycol content, the better the shear rate dependency of the melt viscosity. If the content is less than 18% by mass, the contribution to the melt viscosity is small, and good moldability may not be achieved. The propylene glycol component contained in the polyester elastomer resin is preferably less than 40% by mass in the polyester elastomer resin, more preferably 35% by mass or less.

[0020] When the total alcohol components constituting the polyester elastomer resin is taken as 100 mol %, the polyalkylene glycol is preferably 2 mol % or more and 30 mol % or less, more preferably 3 mol % or more and 20 mol % or less, and even more preferably 3 mol % or more and 15 mol % or less.

[0021] The polyester elastomer resin of the present invention preferably contains one or more trifunctional or higher functional components as copolymerization components. By copolymerizing a trifunctional or higher functional component into the polyester elastomer resin, a branch is introduced into the polyester elastomer resin skeleton, and the shear rate dependency of the melt viscosity can be improved, but the trifunctional or higher functional component is not particularly limited. The component may be either an acid component or an alcohol component, and two or more components may be copolymerized.

[0022] Examples of tri- or higher functional acid components include 1,1,2,2-ethanetetracarboxylic acid, citric acid, 3-hydroxyglutaric acid, dihydroxyglutaric acid, trimellitic acid, trimesic acid, and pyromellitic acid.

[0023] Examples of trifunctional or higher alcohol components include triols such as glycerin, trimethylolethane, trimethylolpropane, trimethylolbutane, and 2-hydroxy-2-methyl-1,4-butanediol, tetraols such as ditrimethylolpropane and pentaerythritol, dipentaerythritol, polyglycerin, and the like, as well as trimethylolpropane ethylene oxide adduct, trimethylolpropane propylene oxide adduct, trimethylolpropane tetrahydrofuran adduct, trimethylolpropane caprolactone adduct, pentaerythritol ethylene oxide adduct, pentaerythritol propylene oxide adduct, pentaerythritol tetrahydrofuran adduct, pentaerythritol caprolactone adduct, dipentaerythritol ethylene oxide adduct, dipentaerythritol propylene oxide adduct, dipentaerythritol tetrahydrofuran adduct, and dipentaerythritol caprolactone adduct.

[0024] The trifunctional or higher alcohol component may be a polyalkylene glycol. For example, polyethylene glycol or polypropylene glycol having a trifunctional or higher polyol such as glycerin added to its terminal may be used. The combination of the added component and the polyether component is not particularly limited.

[0025] As the trifunctional or higher functional component, an acid component is preferable, and with a trifunctional or higher functional acid component, branches can be effectively introduced into both the hard segment and the soft segment. Furthermore, a trifunctional acid component is more preferable, and trimellitic acid is particularly preferable. If the number of functional groups is large, the continuous production stability during polymerization of the polyester elastomer decreases, so a trifunctional acid component is more preferable, and among them, trimellitic acid, which has a highly heat-resistant aromatic ring as a skeleton and is inexpensive, is particularly preferable. As a raw material for polymerizing the polyester elastomer resin, trimellitic anhydride and a methyl ester of trimellitic acid can also be used.

[0026] The blending (copolymerization) amount of trifunctional or higher components is 0 to 1.0 mol%, more preferably 0 to 0.7 mol%, when the total acid components and the total alcohol components, which are the constituent components of the polyester elastomer resin, are 100 mol% and 100 mol%, respectively. If the copolymerization amount exceeds 1.0 mol%, gelation occurs in batch polymerization, making it necessary to clean the machine, and the polymerization yield and continuous productivity decrease. The copolymerization amount of trifunctional or higher components may be 0 mol% by appropriately selecting a polyalkylene glycol that is effective for improving the melt viscosity, such as PEG-PPG-PEG, which has a large PPG content. In order to further exert the effects of the present invention, it is preferable to copolymerize trifunctional or higher components, and in that case, it is preferable that the copolymerization amount is 0.05 to 0.7 mol%, and more preferably 0.1 to 0.5 mol%.

[0027] The hardness of the polyester elastomer resin of the present invention, in Shore D hardness, is preferably from 40 to 60, more preferably from 46 to 55. If the hardness is less than 40, the hardness is too low and there is a risk of tearing when repeatedly pressed, while if the hardness exceeds 60, the hardness is too high, reducing the elongation of the product and causing cracks when repeatedly pressed.

[0028] The polyester elastomer resin of the present invention has high shear rate dependency in melt viscosity. The inventors of the present invention have found the following through their intensive research: No melt fracture phenomenon occurs and good smoothness of the inner surface of a blow molded product can be obtained at a shear rate of 60-80 sec.sup.2 measured by a capillary rheometer. -1 The melt viscosity (a) of the polymer was 120 Pa·s or less. Therefore, the shear rate dependency is good when the shear rate is 60-80 sec -1 The shear rate is 6.08 sec at the measurement temperature where the melt viscosity (a) is 120 Pa s. -1 In this case, the melt viscosity (b) is large. In general, when (b) is 6000 Pa·s or more, drawdown does not occur during molding, and good moldability that allows continuous molding is shown. The larger (b) is, the better the moldability is, and (b) is more preferably 8000 Pa·s or more, and even more preferably 9000 Pa·s or more. There is no particular upper limit for (b), but it is preferably 16000 Pa·s or less. In addition, the melt viscosity is measured using a capillary rheometer. However, in actual blow molding, the temperature is set to be at least 20°C higher than the melting point of the resin, taking into account the load on the molding machine. Therefore, the measurement temperature is set to be at least 20°C higher than the melting point, just like in the actual molding.

[0029] The polyester elastomer resin of the present invention can be polymerized by a general method for producing a polyester elastomer, and the catalyst used in the polymerization is not particularly limited, and general catalysts can be used.

[0030] The reduced viscosity of polyester elastomer resin is not specified, but it is set at a shear rate of 6.08 sec -1In order to achieve a melt viscosity (b) of 6000 Pa·s or more at a shear rate of 6080 sec, the reduced viscosity is preferably 2.0 dl / g or more, and more preferably 2.2 dl / g or more. -1 The measurement temperature for achieving a melt viscosity (a) of 120 Pa s exceeds 270°C, and as the molding temperature of the polyester elastomer resin, the contribution of the decomposition behavior of the resin becomes large, so the reduced viscosity is preferably 2.2 dl / g to 3.0 dl / g.

[0031] The method for increasing the reduced viscosity (thickening) of the polyester elastomer resin is not particularly limited. Melt polycondensation, solid-phase polymerization, and a kneading extrusion method utilizing a reaction between an end group of the polyester elastomer and a thickener, for example, a reaction between an acid end group and a glycidyl-based thickener, can also be applied.

[0032] The polyester elastomer resin of the present invention can also be used as a resin composition by blending various additives described below. It is preferable to blend a general-purpose antioxidant such as an aromatic amine-based, hindered phenol-based, phosphorus-based, sulfur-based, etc., in the polyester elastomer resin of the present invention. The antioxidant may be blended in the polymerization stage, or may be blended by kneading extrusion after the polyester elastomer resin is obtained.

[0033] The polyester elastomer resin of the present invention may contain various other additives, such as resins other than those of the present invention, inorganic fillers, stabilizers, and antioxidants, within the range that does not impair the characteristics of the present invention.

[0034] Other additives that may be added include release agents, color pigments, inorganic and organic fillers, coupling agents, tackiness improvers, quenchers, stabilizers such as metal deactivators, and flame retardants. EXAMPLES

[0035] In order to explain the present invention in more detail, examples are given below, but the present invention is not limited to these examples. The measured values ​​described in the examples were measured by the following methods.

[0036] Melt Viscosity: Using a capillary rheometer (Toyo Seiki F-1), the shear rate was set to 0.5 mm / min (6.08 sec -1 ) to 500mm / min (6080sec -1 The melt viscosity was measured when the temperature was changed from 60 to 80 sec. The measurement temperature was 20°C higher than the melting point of the polyester elastomer resin and 60 to 80 sec. -1 The temperature at which the melt viscosity at a shear rate of 60-80 sec -1 Melt viscosity: Melt viscosity (a), shear rate 6.08 sec -1 Melt viscosity of: Melt viscosity (b) The nozzle shape was: capillary diameter: 1.0 mm, capillary length: 10 mm.

[0037] Blow moldability evaluation: The cylinder temperature of the direct blow molding machine (single screw extruder: L / D=25, full flight screw, screw diameter 65 mm) was set to the measurement temperature of the melt viscosity, and a direct blow molding bottle was produced. A parison forming die lip was attached to the tip of the cylinder, and blow air was sealed in the mold to mold a bottle. The parison retention state at this time was evaluated. ⊚: No drawdown was observed and the shape was maintained. ◯: Drawdown is small and shape is maintained. △: Drawdown is large and the shape tends to collapse, but blow molding is possible. ×: Drawdown is so large that the shape is distorted and blow molding is impossible.

[0038] Melting Point: In accordance with the test method described in JIS K7121, a DuPont V4.0B2000 differential scanning calorimeter was used in an argon atmosphere with a sample mass of 10 mg, a heating start temperature of 30°C, and a heating rate of 20°C / min. The endothermic peak temperature was taken as the melting point.

[0039] Surface hardness: The surface hardness was measured in an environment of 23°C according to the test method (Shore D) described in ASTM D2240. Three injection molded products (width 100mm, length 100mm, thickness 2.0mm) made with a cylinder temperature of 20°C above the melting point of the resin and a mold temperature of 50°C were stacked on top of each other, and the surface hardness was measured by reading the instantaneous value of Shore D when a needle tip was dropped onto them.

[0040] Reduced Viscosity: 0.02 g of the thoroughly dried polyester elastomer resin was dissolved in 10 ml of a mixed solvent of phenol / tetrachloroethane (mass ratio 6 / 4), and the viscosity was measured at 30° C. using an Ubbelohse viscometer.

[0041] Resin compatibility: After the resin was produced, the compatibility between the hard segment and the soft segment was evaluated by visually inspecting the appearance of the resin when molten. ◯: The molten resin is transparent and has sufficient compatibility. △: The molten resin is semi-transparent (slightly cloudy) and the compatibility is low. ×: The molten resin was cloudy and the compatibility was extremely low.

[0042] Tensile elongation: The cylinder temperature was 20°C above the melting point of the resin, and the mold temperature was 50°C. The injection molded product (width 100 mm, length 100 mm, thickness 2.0 mm) was punched perpendicular to the direction of resin flow to prepare a JIS No. 3 dumbbell-shaped test piece. The tensile elongation (elongation at break) was then measured according to JIS K6251:2010.

[0043] Example of a method for producing polyester elastomer resin Example 1: According to the method described in JP-A-9-59491, a polyester elastomer resin with terephthalic acid / trimellitic acid / 1,4-butanediol / PPG-PEG#3000 of 99.9 / 0.1 / / 96 / 4 (mol%) was produced. Then, solid-phase polymerization was carried out to increase the reduced viscosity. The melting point of this polyester elastomer resin was 218°C, and the reduced viscosity was 2.4 dl / g.

[0044] In the same manner, Examples 2 to 7 (Example 6 is a reference example) Thus, polyester elastomer resins of Comparative Examples 1 to 6 were produced. The raw materials used, compositions, and evaluation results are shown in Table 1. The polyalkylene glycols used are as follows. PPG-PEG#2900: PEG-PPG-PEG block copolymer (number average molecular weight 2900, PG / EG=60 / 40 (mass%), Sanyo Chemical Industries, Ltd., Newpol PE-64) PPG-PEG#1100: PEG-PPG-PEG block copolymer (number average molecular weight 1100, PG / EG=90 / 10 (mass%), ADEKA Adeka Pluronic L-31) PPG-PEG#4200: PEG-PPG-PEG block copolymer (number average molecular weight 4200, PG / EG=50 / 50 (mass%), NOF Corp. Poloxamer 185) PEG#1000: Polyethylene glycol (number average molecular weight 1000, NOF Corp.) PPG#3000: Polypropylene glycol (number average molecular weight 3000, Sannix PP-3000 manufactured by Sanyo Chemical Industries) PTMG#1000: Polytetramethylene glycol (number average molecular weight 1000, manufactured by Mitsubishi Chemical) PTMG#3000: Polytetramethylene glycol (number average molecular weight 3000, Mitsubishi Chemical (Manufacturer)

[0045] The number average molecular weight of each polyalkylene glycol was measured as follows: 16 mg of polyalkylene glycol was weighed out and dissolved in 8 ml of chloroform, and the solution was filtered through a 0.2 μm membrane filter to obtain a sample solution, which was then subjected to gel permeation chromatography. The molecular weight was calculated based on standard polystyrene. The apparatus used was a TOSOH HLC-8320GPC, and the solvent was a mixed solvent of chloroform / hexafluoroisopropanol = 98 / 2 (volume ratio). Measurements were performed under conditions of a flow rate of 0.6 ml / min, a concentration of 0.2%, an injection volume of 20 ml, and a temperature of 40°C.

[0046] Examples 1 to 7 are examples where (b) is 8000 Pa·s or more at the measurement temperature where the melt viscosity (a) is 120 Pa·s. Examples 1 to 3 show that increasing the amount of trifunctional or higher functional components increases the melt viscosity (b), and moldability can be improved. Examples 4 and 5 show that sufficient melt viscosity characteristics can be achieved even when different acid components are copolymerized. Moreover, Example 6 shows that the propylene glycol content in the polyoxyethylene polyoxypropylene glycol is high, and sufficient melt viscosity characteristics for good moldability can be obtained even without trifunctional or higher functional components.

[0047] Comparative Examples 1 to 6 show examples in which blow moldability and product properties are not sufficient. In Comparative Example 1, the melt viscosity was low, drawdown occurred, and moldability was poor. In Comparative Example 2, the number average molecular weight of polyoxyethylene polyoxypropylene glycol is large, and the resin compatibility is poor. Although an apparent increase in melt viscosity due to low compatibility is observed, sufficient elongation properties are not satisfied. In Comparative Example 3, the polyalkylene glycol is polyethylene glycol, not a block copolymer with polypropylene glycol, and the melt viscosity is low, resulting in poor moldability, and the crystallinity is high, resulting in insufficient elongation properties. In Comparative Example 4, the polyalkylene glycol is polypropylene glycol, and due to the presence of terminal secondary hydroxyl groups, the degree of polymerization and reduced viscosity are difficult to increase, sufficient melt viscosity characteristics are not exhibited, and the elongation characteristics are also insufficient. In Comparative Example 5, the polyalkylene glycol is polytetramethylene glycol, which is not a block copolymer with polypropylene glycol or the like, and does not satisfy sufficient melt viscosity characteristics. In Comparative Example 6, the polyalkylene glycol is polytetramethylene glycol, and the number average molecular weight is large, so that the resin compatibility is low, the moldability is poor, and the tensile elongation property is not sufficient.

[0048] [Table 1] [Industrial Applicability]

[0049] The polyester elastomer resin of the present invention is a resin that can be applied to a wide range of blow molding techniques and can accommodate the increasing length and complexity of blow molded products that will be required in the future to reduce the weight of automobiles, and it will make an extremely significant contribution to the industrial world.

Claims

1. The polyester elastomer resin comprises an acid component including an aromatic dicarboxylic acid, an aliphatic and / or alicyclic diol, and an alcohol component including a polyalkylene glycol as constituent components. When the total acid components are 100 mol % and the total alcohol components are 100 mol %, the copolymerization component contains 0.05 to 1.0 mol % of one or more trifunctional or higher functional components, the polyalkylene glycol is a block copolymer and has a number average molecular weight of 1,000 to 4,000; the polyalkylene glycol is polyoxyethylene polyoxypropylene glycol, The propylene glycol component contained in the polyester elastomer resin is 18 to 35% by mass in the polyester elastomer resin, The melt viscosity characteristics measured by a capillary rheometer are 20°C higher than the melting point of the polyester elastomer resin and at a shear rate of 6080 sec. －１ The shear rate was measured at a temperature at which the melt viscosity of the mixture was 120 Pa·s. －１ 2. A polyester elastomer resin for blow molding, characterized in that the melt viscosity of said polyester elastomer resin for blow molding is 6000 Pa·s or more.

2. 2. The polyester elastomer resin for blow molding according to claim 1, wherein the polyalkylene glycol is a block copolymer having a polyethylene glycol (PEG)-polypropylene glycol (PPG)-polyethylene glycol (PEG) structure.

3. 3. The polyester elastomer resin for blow molding according to claim 1, wherein the tri- or higher functional component is an acid component.

4. 4. The polyester elastomer resin for blow molding according to claim 1, wherein the tri- or higher functional component is trimellitic acid.

5. A blow molded article comprising the polyester elastomer resin according to any one of claims 1 to 4.

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