Thermoplastic polyester elastomer, resin composition containing the same, and molded article obtained therefrom

Abstract

A thermoplastic polyester elastomer is provided, particularly exhibiting excellent extrudability and extrusion stability, and capable of stably producing hollow and elongated molded articles with uniform thickness through extrusion molding over extended periods. A polyester elastomer is composed of hard segments and soft segments bonded together, wherein the hard segments are composed of polyesters consisting of aromatic dicarboxylic acids and aliphatic or alicyclic diols, and the soft segments are composed of aliphatic polycarbonate. At least a portion of the terminal groups of the polyester elastomer are capped with a reactive compound containing polycarbodiimide. The acid value of the polyester elastomer is 15 eq / ton or less, and at 230°C, (i) the melt viscosity at a preheating time of 5 minutes and a shear rate of 10 / s is 1800 Pa·s or more, and the melt viscosity at a preheating time of 5 minutes and a shear rate of 1000 / s is 800 Pa·s or less; and (ii) the ratio of the melt viscosity at a shear rate of 10 / s measured at preheating times of 5 minutes and 25 minutes is 0.7 to 1.3.

Description

Technical Field

[0001] This invention relates to a thermoplastic polyester elastomer that exhibits excellent heat resistance, weather resistance, heat aging resistance, water resistance, and low-temperature properties, as well as excellent processability, particularly extrusion molding properties and extrusion molding stability. The invention also relates to a resin composition containing this elastomer and molded articles obtained therefrom. Background Technology

[0002] In recent years, the materials used for automotive and home appliance components such as cables and hoses have been shifting from metals or rubber to thermoplastic resins. Furthermore, with the increasing performance of automobiles and home appliances, multiple components are being installed in close proximity, increasing the likelihood of resin components being exposed to unprecedentedly high temperatures. Therefore, there is a strong demand to develop a resin that combines heat aging resistance, flame retardancy, and water resistance.

[0003] To date, the resins used to make cables have mainly included vinyl chloride resins, olefin resins, and polyester resins. However, vinyl chloride and olefin resins suffer from low melting points and poor heat resistance. Furthermore, while polyester resins have relatively high melting points, their poor hydrolysis resistance poses problems for outdoor and vehicle applications. To address these issues, some have proposed using thermoplastic polyester elastomers as the constituent resin for cables.

[0004] The aforementioned thermoplastic polyester elastomers are traditionally known to have products with crystalline polyesters, such as polybutylene terephthalate (PBT) and polybutylene naphthalate (PBN), as hard segments, and polyesters such as polytetramethylene glycol (PTMG) and / or polycaprolactone (PCL) and polybutylene adipate (PBA) as soft segments, and have been put into practical use (for example, see Patent Documents 1 and 2).

[0005] As shown in Patent Document 1, polyester-polyether elastomers using polyoxymethylene glycol in the soft chain segment have excellent water resistance and low-temperature properties, but poor heat aging resistance. In addition, as shown in Patent Document 2, polyester-polyester elastomers using polyester in the soft chain segment have excellent heat aging resistance, but poor water resistance and low-temperature properties, neither of which can meet the market requirements in recent years.

[0006] To address these issues, a thermoplastic polyester elastomer with improved heat resistance and water resistance was proposed by using aliphatic polycarbonate in the soft chain segment (see Patent Document 3).

[0007] However, because the thermoplastic polyester elastomer in Patent Document 3 is prone to viscosity increase during extrusion molding, and the melt viscosity is very difficult to control, it is difficult to stably produce hollow and long-sized molded articles such as cables or hoses with uniform thickness through extrusion molding for a long time. [Existing Technical Documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 10-17657 [Patent Document 2] Japanese Patent Application Publication No. 2003-192778 [Patent Document 3] Japanese Patent No. 4244067 Summary of the Invention [The problem the invention aims to solve]

[0009] This invention was developed to overcome the problems of conventional thermoplastic polyester elastomers. Its purpose is to provide a thermoplastic polyester elastomer that not only has excellent heat resistance, weather resistance, heat aging resistance, water resistance, and low-temperature properties, but also excellent extrusion molding properties and extrusion molding stability. Furthermore, it can stably produce hollow and long molded products such as cables or hoses with uniform thickness through extrusion molding over a long period of time. [Technical means to solve the problem]

[0010] To achieve the aforementioned objectives, the inventors conducted in-depth research on methods to prevent viscosity increases during extrusion molding of conventional thermoplastic polyester elastomers using aliphatic carbonates in the soft chain segments. The results showed that by appropriately controlling the acid value, melt viscosity at low shear rates, and melt viscosity at high shear rates of the thermoplastic polyester elastomer within specific ranges, extrudability can be improved. Simultaneously, by appropriately controlling the change in melt viscosity over time at low shear rates (retention stability) within a specific range, viscosity increases during long-term extrusion molding can be suppressed, thus improving extrusion molding stability. Furthermore, it was found that to control melt viscosity and retention stability within specific ranges, it is important to end-group the thermoplastic polyester elastomer with reactive compounds possessing reactive functional groups. This allows for the increase of molecular weight / branching of the thermoplastic polyester elastomer, thereby reducing the acid value of the thermoplastic polyester elastomer to a specific range.

[0011] The present invention is based on the above findings and has the following (1) to (5) configurations. (1) A thermoplastic polyester elastomer, characterized in that it is composed of hard segments and soft segments bonded together, wherein the hard segments are composed of polyester consisting of aromatic dicarboxylic acids and aliphatic or alicyclic diols, and the soft segments are mainly composed of aliphatic polycarbonate, wherein at least a portion of the terminal groups of the thermoplastic polyester elastomer are capped by a reactive compound containing polycarbodiimide. The acid value of the thermoplastic polyester elastomer is below 15 eq / ton. According to JIS K7199, when the melt viscosity of the thermoplastic polyester elastomer is measured at 230°C, the following conditions (i) and (ii) must be met: (i) The melt viscosity is above 1800 Pa·s when the preheating time is 5 minutes and the shear rate is 10 / second, and the melt viscosity is below 800 Pa·s when the preheating time is 5 minutes and the shear rate is 1000 / second; (ii) The ratio of melt viscosity at a shear rate of 10 / s, measured at preheating times of 5 minutes and 25 minutes, is 0.7 to 1.3. (2) The thermoplastic polyester elastomer according to (1) is characterized in that it further contains a reactive compound having at least one functional group selected from glycidyl group, anhydride group and isocyanate group as a reactive compound. (3) A resin composition, characterized in that it contains the thermoplastic polyester elastomer described in (1) or (2) and a flame retardant. (4) A molded article, characterized in that it is obtained by extrusion molding of the thermoplastic polyester elastomer described in (1) or (2) or the resin composition described in (3). (5) The molded article according to (4) is characterized in that the molded article is a cable or a hose. [The effects of the invention]

[0012] The thermoplastic polyester elastomer of the present invention not only meets the basic performance requirements for automotive and home appliance components, such as heat resistance, weather resistance, heat aging resistance, and low temperature characteristics, but also has excellent extrusion moldability and extrusion molding stability, thus enabling the stable production of hollow and long-sized molded products such as cables or hoses with uniform thickness through extrusion molding over a long period of time. Detailed Implementation

[0013] The thermoplastic polyester elastomer of the present invention is characterized by being based on a thermoplastic polyester elastomer composed of hard segments and soft segments bonded together, wherein the hard segments are composed of polyesters consisting of aromatic dicarboxylic acids and aliphatic or alicyclic diols, and the soft segments are mainly composed of aliphatic polycarbonate; at least a portion of the terminal groups of the thermoplastic polyester elastomer are capped with a reactive compound containing polycarbodiimide; it has a specific range of acid values, and thus a specific range of melt viscosity at low shear rates and melt viscosity at high shear rates, as well as a specific range of melt viscosity at low shear rates that varies over time (retention stability).

[0014] First, the hard segment of the thermoplastic polyester elastomer will be explained. This hard segment is composed of polyester consisting of aromatic dicarboxylic acids and aliphatic or alicyclic diols.

[0015] In the hard-chain polyester components of thermoplastic polyester elastomers, conventional aromatic dicarboxylic acids are widely used as aromatic dicarboxylic acids, without particular limitation, but terephthalic acid or naphthalenedicarboxylic acid are preferred. Other acid components include aromatic dicarboxylic acids such as biphenyl phthalic acid, isophthalic acid, and sodium isophthalate-5-sulfonate; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and tetrahydrophthalic anhydride; and aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanoic acid, dimer acid, and hydrogenated dimer acid. These should be used within a range that does not excessively lower the melting point of the resin, and the amount used is preferably less than 30 mol% of the total acid content, more preferably less than 20 mol%.

[0016] Furthermore, in the hard-chain polyester components of thermoplastic polyester elastomers, conventional aliphatic or alicyclic diols are widely used as constituents, without particular limitation, but alkylene diols with 2 to 8 carbon atoms are primarily preferred. Specifically, examples include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and 1,4-cyclohexanediethanol. Among these, 1,4-butanediol and 1,4-cyclohexanediethanol are most preferred.

[0017] Specifically, from the perspective of physical properties, formability, and cost-effectiveness, the components of the hard chain segment of the thermoplastic polyester elastomer are preferably composed of butylene terephthalate units or butylene dinaphthalate units.

[0018] The polyester constituting the hard segments of the thermoplastic polyester elastomer can be obtained according to conventional polyester preparation methods. The polyester is preferably a substance with a number average molecular weight of 10,000 to 40,000.

[0019] Next, the soft segment of the thermoplastic polyester elastomer will be described. This soft segment is mainly composed of aliphatic polycarbonate. Here, "mainly" means that aliphatic polycarbonate accounts for more than 60% by mass of the soft segment, preferably more than 80% by mass, and more preferably more than 90% by mass.

[0020] The aliphatic polycarbonate constituting the soft segments of the thermoplastic polyester elastomer is preferably composed mainly of aliphatic diol residues having 2 to 12 carbon atoms. Examples of such aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,9-nonanediol, and 2-methyl-1,8-octanediol. From the perspective of the softness and low-temperature properties of the resulting polyester elastomer resin composition, aliphatic diols having 5 to 12 carbon atoms are particularly preferred. These components can be used alone or in combination of two or more as needed.

[0021] Aliphatic polycarbonate diols, which are soft segments constituting thermoplastic polyester elastomers and possess good low-temperature properties, are preferably those with low melting points (e.g., below 70°C) and low glass transition temperatures. Generally, aliphatic polycarbonate diols composed of 1,6-hexanediol, the soft segment used to form thermoplastic polyester elastomers, have glass transition temperatures as low as -60°C and melting points of around 50°C, thus exhibiting good low-temperature properties. Other aliphatic polycarbonate diols mentioned above, such as those obtained by copolymerizing 3-methyl-1,5-pentanediol in appropriate amounts, although having slightly higher glass transition temperatures than the original aliphatic polycarbonate diols, are equivalent to aliphatic polycarbonate diols with good low-temperature properties due to their lower melting points or amorphous nature. In addition, for example, aliphatic polycarbonate diols composed of 1,9-nonanediol and 2-methyl-1,8-octanediol have a melting point of about 30°C and a glass transition temperature of about -70°C, which are very low and are equivalent to aliphatic polycarbonate diols with good low-temperature properties.

[0022] The aforementioned aliphatic polycarbonate diols are not limited to polycarbonate components; they can also be copolymerized in small amounts with other diols, dicarboxylic acids, ester compounds, or ether compounds. Examples of copolymer components include diols such as dimer glycols, hydrogenated dimer glycols and their modifications; dicarboxylic acids such as dimer acids and hydrogenated dimer acids; polyesters or oligoesters composed of aliphatic, aromatic, or alicyclic dicarboxylic acids and diols; polyesters or oligoesters composed of ε-caprolactone, etc.; and polyalkylene glycols or oligoalkylene glycols such as polytetramethylene glycol and polyoxyethylene glycol.

[0023] The amount of the aforementioned copolymer component should be within a range that will not substantially cause the aliphatic polycarbonate segments to lose their effect. Specifically, it should be 40 parts by weight or less, preferably 30 parts by weight or less, and more preferably 20 parts by weight or less, relative to 100 parts by weight of aliphatic polycarbonate segments. Excessive amounts of the copolymer component will deteriorate the heat aging resistance and water resistance of the resulting polyester elastomer resin composition.

[0024] In thermoplastic polyester elastomers, the mass ratio of polyester constituting the hard segment to aliphatic polycarbonate constituting the soft segment and copolymer components added as needed is typically hard segment: soft segment = 30:70 to 95:5, preferably 40:60 to 90:10, more preferably 45:55 to 87:13, and most preferably in the range of 50:50 to 85:15.

[0025] Thermoplastic polyester elastomers are formed by bonding hard segments and soft segments. The hard segments are composed of polyesters consisting of aromatic dicarboxylic acids and aliphatic or alicyclic diols, as described above, while the soft segments are mainly composed of aliphatic polycarbonates. Here, "bonded" does not mean that the hard and soft segments are bonded by chain extenders such as isocyanate compounds, but rather preferably that the units constituting the hard and soft segments are directly bonded by ester or carbonate bonds. To obtain such a state, for example, it is preferable to subject the polyester constituting the hard segments, the polycarbonate constituting the soft segments, and any copolymer components added as needed to a molten state through repeated transesterification and depolymerization end-capping reactions for a period of time to obtain the thermoplastic polyester elastomer.

[0026] The aforementioned end-capping reaction is preferably carried out at a temperature within the range of the melting point of the polyester constituting the hard segment to +30°C. In this reaction, the concentration of the active catalyst in the system can be arbitrarily set according to the reaction temperature. That is, since the transesterification and depolymerization reactions proceed rapidly at higher reaction temperatures, a lower concentration of the active catalyst in the system is preferred; furthermore, at lower reaction temperatures, a certain concentration of the active catalyst is preferred.

[0027] The catalyst can be any conventionally used substance, such as one or more titanium compounds like tetrabutoxytitanium and potassium titanium oxalate, or tin compounds like dibutyltin oxide and monohydroxybutyltin oxide. The catalyst can be pre-existing in the polyester or polycarbonate, in which case it does not need to be added again. Furthermore, the catalyst in the polyester or polycarbonate can be pre-deactivated partially or substantially completely by any method. For example, when tetrabutoxytitanium is used as the catalyst, deactivation can be achieved by adding phosphoric acid, phosphoric acid, triphenyl phosphate, tris(triethylene glycol) phosphate, orthophosphoric acid, diethyl ethoxycarbonylmethylphosphonate, triphenyl phosphite, trimethyl phosphate, trimethyl phosphite, etc., but this is not a limitation.

[0028] The above reaction can be carried out under any determined combination of reaction temperature, catalyst concentration, and reaction time. That is, the reaction conditions can be varied according to various factors such as the type and ratio of hard and soft segments used, the shape of the apparatus used, and the stirring conditions, and the optimal values ​​can be appropriately adopted.

[0029] The optimal values ​​for the above reaction conditions exist, for example, when the melting point of the resulting chain-grown polymer differs from that of the polyester used for the hard segment by 2°C to 60°C. When the melting point difference is less than 2°C, the two segments cannot mix and / or react, resulting in a polymer with poor elastic properties. On the other hand, when the melting point difference is greater than 60°C, the transesterification reaction proceeds significantly, leading to reduced end-capping properties of the resulting polymer and deterioration in crystallinity and elastic properties.

[0030] The residual catalyst in the molten mixture obtained by the above reaction should preferably be deactivated as completely as possible using conventionally known methods. If more than necessary catalyst remains, the transesterification reaction will continue during mixing and molding, and the physical properties of the resulting polymer will change.

[0031] The deactivation reaction can be carried out by, for example, the method described above, namely by adding phosphorous compounds such as phosphorous acid, phosphoric acid, triphenyl phosphate, tri(triethylene glycol) phosphate, orthophosphoric acid, diethyl ethoxycarbonylmethylphosphonate, triphenyl phosphite, trimethyl phosphate, and trimethyl phosphite, but is not limited to these methods.

[0032] Thermoplastic polyester elastomers may also contain limited amounts of trifunctional or higher polycarboxylic acids and polyols. Examples include trimellitic anhydride, benzophenone tetracarboxylic acid, trimethylolpropane, and glycerol.

[0033] In this invention, the thermoplastic polyester elastomer is in a state where at least a portion of its terminal groups are capped with a reactive compound. Hereinafter, the thermoplastic polyester elastomer in this state may be referred to as a "terminus-capped thermoplastic polyester elastomer." By capping at least a portion of the terminal groups of the thermoplastic polyester elastomer with a reactive compound, the thermoplastic polyester elastomer can be increased in molecular weight / branched, etc., and the acid value of the thermoplastic polyester elastomer can be effectively reduced, thereby improving the melt viscosity characteristics and retention stability of the thermoplastic polyester elastomer.

[0034] Furthermore, in this invention, "at least a portion of the terminal groups of the thermoplastic polyester elastomer are capped by the reactive compound" means that it is not required that "all" of the terminal groups of the thermoplastic polyester elastomer are capped by the reactive compound. In this invention, it is anticipated that "most" of the terminal groups of the thermoplastic polyester elastomer are capped by the reactive compound, including compositions in which free reactive compounds are mixed. This is because even with excessive addition of the reactive compound and the following improvements to the addition method, it is difficult to ensure that "all" of the terminal groups of the thermoplastic polyester elastomer are capped by the reactive compound. The capping ratio of the terminal groups of the thermoplastic polyester elastomer is difficult to determine directly, but can be estimated using the acid value of the thermoplastic polyester elastomer as a standard. As the terminal groups of the thermoplastic polyester elastomer are capped, the acid value of the thermoplastic polyester elastomer will decrease compared to the original acid value.

[0035] In this invention, the reactive compound, by end-capping the terminal groups of the thermoplastic polyester elastomer, can induce branching in the elastomer and increase its molecular weight, thereby controlling the melt viscosity characteristics at both low and high shear rates within a suitable range. End-capping the terminal groups also reduces the acid value and improves the retention stability of the melt viscosity. In this invention, the reactive compound is not particularly limited as long as it possesses functional groups capable of reacting with the terminal groups (hydroxyl or carboxyl groups) of the thermoplastic polyester elastomer, but it must contain at least polycarbodiimide. Polycarbodiimide, in particular, excels in reducing the acid value of the thermoplastic polyester elastomer, thus greatly contributing to improving the retention stability of the melt viscosity. The polycarbodiimide used in this invention can be any polycarbodiimide having two or more carbodiimide groups (-N=C=N- structure) within one molecule. Examples include aliphatic polycarbodiimides, alicyclic polycarbodiimides, aromatic polycarbodiimides, and copolymers thereof. Aliphatic or alicyclic polycarbodiimides are preferred.

[0036] Polycarbodiimide can be obtained, for example, through the decarboxylation reaction of diisocyanate compounds. Examples of diisocyanate compounds used herein include 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate, phenylenedimethyl diisocyanate, isophorone diisocyanate, methylcyclohexane diisocyanate, tetramethylphenyldimethyl diisocyanate, and 1,3,5-triisopropylphenylene-2,4-diisocyanate. These can be used alone or in copolymerization of two or more compounds. In addition, branched structures can be introduced, or functional groups other than carbodiimide groups or isocyanate groups can be introduced through copolymerization. Furthermore, the terminal isocyanate groups can be used directly, or the degree of polymerization can be controlled by reacting the terminal isocyanate groups, or a portion of the terminal isocyanate can be capped.

[0037] From the perspective of stability and processability, polycarbodiimide preferably contains isocyanate groups at the end, and the content of isocyanate groups is 0.5% to 4% by mass. More preferably, the content of isocyanate groups is 1% to 3% by mass. Polycarbodiimide derived from dicyclohexylmethane diisocyanate and isophorone diisocyanate is particularly preferred, and the content of isocyanate groups is within the above range. In addition, the content of isocyanate groups can be determined by conventional methods (back titration with hydrochloric acid after dissolving in amine).

[0038] From the perspective of stability and processability, polycarbodiimide preferably contains 2 to 50 carbodiimide groups per molecule. More preferably, it contains 5 to 30 carbodiimide groups per molecule. As long as the polycarbodiimide is obtained from a diisocyanate compound, the number of carbodiimide groups (i.e., the number of carbodiimide groups) in the polycarbodiimide molecule corresponds to the degree of polymerization. For example, the degree of polymerization of polycarbodiimide obtained by chain bonding of 21 diisocyanate compounds is 20, and the number of carbodiimide groups in the molecular chain is 20. Typically, polycarbodiimide is a mixture of molecules of various lengths, and the number of carbodiimide groups is expressed as an average value. A uniform number of carbodiimide groups within the above range, when solid near room temperature, can be powdered, exhibits excellent workability and compatibility when mixed with the following thermoplastic polyester elastomers, and is also preferred in terms of uniform reactivity and resistance to exudation. Furthermore, the number of carbodiimide groups can be determined by, for example, conventional methods (back titration with hydrochloric acid after dissolution in an amine).

[0039] The reactive compound used in this invention can be any polycarbodiimide, and may further contain a reactive compound having at least one functional group selected from glycidyl (epoxy), anhydride, and isocyanate groups, as needed. The reactive compound contains at least two functional groups per molecule. As described above, polycarbodiimide is excellent at lowering the acid value of thermoplastic polyester elastomers, but due to its spatial structure, it is less effective at branching thermoplastic polyester elastomers. Therefore, by further containing a reactive compound having at least one functional group selected from glycidyl (epoxy), anhydride, and isocyanate groups, the weaknesses of polycarbodiimide can be overcome.

[0040] When the reactive compound is a compound containing an epoxy group (glycidyl group), it is preferably a polyfunctional glycidyl compound with two or more glycidyl groups. Examples include 1,6-dihydroxynaphthalene diglycidyl ether and 1,3-benzenediol diglycidyl ether with two glycidyl groups; 1,3,5-triglycidyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione and dipropylene glycol triglycidyl ether with three glycidyl groups; and 1-chloro-2,3-epoxypropane·formaldehyde·2,7-naphthalenediol condensate and pentaerythritol glycidyl ether with four glycidyl groups. Among these, polyfunctional epoxy compounds with a heat-resistant skeleton are preferred. Particularly preferred are difunctional or tetrafunctional epoxy compounds with a naphthalene skeleton, or trifunctional epoxy compounds with a triazine skeleton. Considering the increase in viscosity of thermoplastic polyester elastomer solutions, the effect of effectively reducing the acid value of thermoplastic polyester elastomers, and the degree of gelation caused by the coagulation and curing of epoxy itself, difunctional or trifunctional epoxy compounds are preferred.

[0041] In addition, the following copolymers can be listed: each molecule contains more than two glycidyl groups, the weight average molecular weight is 4,000 to 25,000, and is composed of (X) 20 to 99% by mass of vinyl aromatic monomers, (Y) 1 to 80% by mass of glycidyl methacrylate, and (Z) 0 to 79% by mass of vinyl monomers other than (X) without epoxy groups.

[0042] When the reactive compound is a compound containing an anhydride group, compounds containing 2 to 4 anhydride groups per molecule are preferred from the perspective of stability and processability. Examples of such compounds include phthalic anhydride, trimellitic anhydride, and pyromellitic anhydride.

[0043] When the reactive compound is a compound having an isocyanate group, isocyanate compounds that serve as raw materials for the aforementioned polycarbodiimide can be listed.

[0044] Next, the method for capping end groups using a reactive compound will be explained. To cap the end groups of a thermoplastic polyester elastomer with a reactive compound, simply mix the thermoplastic polyester elastomer and the reactive compound, bringing them into contact. Through this contact, the reactive functional groups in the reactive compound react with the end groups of the thermoplastic polyester elastomer, thus capping the end groups. Although the reaction between the end groups of the thermoplastic polyester elastomer and the reactive functional groups in the reactive compound can occur without a catalyst, it is preferable to use a catalyst to promote the reaction. Amines, imidazoles, etc., are generally preferred catalysts.

[0045] When the reactive compound is polycarbodiimide, its mixing amount is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, relative to 100 parts by mass of thermoplastic polyester elastomer. When the amount exceeds the upper limit, the softness is impaired, and the mechanical properties, heat resistance, and melt viscosity may sometimes decrease. Furthermore, when the amount is below the lower limit, the amount of -N=C=N- in the thermoplastic polyester elastomer decreases, and the improvement effect on hydrolysis resistance and extrusion moldability may sometimes be worse. On the other hand, when the reactive compound is a reactive compound containing at least one functional group selected from glycidyl (epoxy), anhydride, and isocyanate groups, its mixing amount is preferably 0.1 to 4.5 parts by mass, more preferably 0.1 to 4 parts by mass, relative to 100 parts by mass of thermoplastic polyester elastomer. When the amount exceeds the upper limit, the thickening effect is excessive, which may sometimes adversely affect the moldability and mechanical properties of the molded article. Furthermore, when the amount is below the lower limit, the target effect of generating branches or growing molecular chains may sometimes be insufficient.

[0046] Furthermore, to ensure that the mixed reactive compound can contact and react with the end groups of the thermoplastic polyester elastomer, it is preferable to design the order in which the reactive compound is added to the thermoplastic polyester elastomer. For example, instead of simultaneously mixing the thermoplastic polyester elastomer with the reactive compound and additives such as flame retardants that can be mixed as desired, as is the case in the past, the reactive compound is pre-added to a portion of the thermoplastic polyester elastomer. On the other hand, the remaining thermoplastic polyester elastomer and additives are pre-mixed and melted. When the thermoplastic polyester elastomer with the added reactive compound is added to this melt, the reactive compound can be uniformly melted and mixed, ensuring that the reactive mixture contacts and reacts with the end groups of the thermoplastic polyester elastomer. If the reactive compound is not uniformly melted and mixed, the end groups of the thermoplastic polyester elastomer will not be adequately capped, and unreacted reactive compounds will remain in the composition, causing adverse effects during extrusion molding. Specifically, if unreacted reactive compounds are present, they are prone to thermal decomposition or hydrolysis due to prolonged retention during extrusion molding, which may lead to a decrease in molecular weight or melt viscosity. In addition, if unreacted reactive compounds are present, gelation may occur, and the melt viscosity may easily increase.

[0047] The thermoplastic polyester elastomer with end-capped groups obtained by this method has a lower acid value compared to the original thermoplastic polyester elastomer due to the end-capping of its acid groups. Specifically, it can achieve a low acid value of less than 15 eq / ton, preferably less than 10 eq / ton, and more preferably less than 5 eq / ton. There is no particular limitation on the lower limit of the acid value; for example, it can be 0 eq / ton. When the acid value is within the above range, the retention stability of the melt viscosity during molding increases, and the thickness uniformity is improved when extruding hollow, long-dimensional products such as cables and hoses. Furthermore, the acid value also contributes to heat resistance, heat aging resistance, and hydrolysis resistance; when the acid value is within the above range, these properties are excellent.

[0048] The following provides a detailed description of the melt viscosity characteristics. The thermoplastic polyester elastomer with end-group capping of the present invention is characterized in that, when the melt viscosity is measured at 230°C according to JIS K7199, it satisfies the following (i) and (ii): (i) The melt viscosity at a preheating time of 5 minutes and a shear rate of 10 / second is 1800 Pa·s or more, preferably 2500 Pa·s or more, and the melt viscosity at a preheating time of 5 minutes and a shear rate of 1000 / second is 800 Pa·s or less, preferably 700 Pa·s or less. (ii) The ratio of melt viscosity at a shear rate of 10 / second, measured at a preheating time of 5 minutes and a preheating time of 25 minutes, is 0.7 to 1.3, preferably 0.8 to 1.2. Furthermore, there is no particular limit to the upper limit of the melt viscosity at a preheating time of 5 minutes and a shear rate of 10 / second, for example, 50000 Pa·s; and there is no particular limit to the lower limit of the melt viscosity at a preheating time of 5 minutes and a shear rate of 1000 / second, for example, 150 Pa·s.

[0049] Excellent extrudability can be provided by keeping the melt viscosity within the range specified in (i). Specifically, when extruding thermoplastic polyester elastomers or resin compositions containing them with end groups, due to their sufficient shape retention and sufficient flowability for obtaining extruded articles of films or small shapes, it is possible to perform highly complex shape designs such as those requiring hollow, long, and uniformly thick molded articles.

[0050] The means to satisfy (i) above are not particularly limited. For example, as described above, by end-capping the terminal groups of the thermoplastic polyester elastomer with a reactive compound, the thermoplastic polyester elastomer can be branched, and the molecular weight of the thermoplastic polyester elastomer can be increased. Furthermore, by copolymerizing the thermoplastic polyester elastomer with trimethylolpropane during polymerization, branching of the thermoplastic polyester elastomer can be achieved. Further examples include mixing a branched / high molecular weight thermoplastic polyester elastomer into the thermoplastic polyester elastomer. Through these branching or high molecular weight increases, the entanglement of polymer chains increases in the low shear rate range, the melt viscosity increases, and it becomes less deformable (enhanced shape stability). On the other hand, in the high shear rate range, the entanglement of molecular chains becomes less severe, and it flows more easily, reducing the aforementioned thickening effect. It can be considered that this phenomenon can improve the thickness uniformity during extrusion molding.

[0051] On the other hand, by keeping the melt viscosity within the range of (ii), sufficient retention stability can be achieved, making long-term stable production possible. The means to satisfy (ii) are not particularly limited; for example, as mentioned above, reducing the acid value of the thermoplastic polyester elastomer by capping the end groups with a reactive compound. In this case, it is important to carefully control the presence of acid group residue at the ends of the thermoplastic polyester elastomer. Furthermore, it is also important to minimize the presence of unreacted reactive compounds. If uncapped thermoplastic polyester elastomer is present, thermal decomposition or hydrolysis is likely to occur due to retention during long-term extrusion molding, potentially leading to a decrease in molecular weight and melt viscosity. Furthermore, the presence of unreacted reactive compounds may cause gelation, easily increasing the melt viscosity.

[0052] In this invention, although the end-group-terminated thermoplastic polyester elastomer can be used alone as a molding material, it can also be used in combination with a flame retardant in the form of a resin composition, which is advantageous in improving the flame retardancy of the resulting molded article. The flame retardant can be halogenated or non-halogenated flame retardants, flame retardant additives, which can be used alone or in combination. Examples of flame retardants include, for instance, triazine compounds and / or their derivatives, phosphorus compounds, bromine compounds, antimony compounds, etc. The resin composition may contain 1 to 40% by weight of the flame retardant.

[0053] Examples of triazine compounds and / or their derivatives include melamine, melamine cyanurate, melamine phosphate, and guanidine aminosulfonate. Examples of phosphorus compounds include red phosphorus compounds and ammonium polyphosphates. Examples of bromine compounds include brominated phenoxy resins, brominated epoxy resins, brominated epoxy oligomers, TBA carbonate oligomers, ethylene bis(tetrabromophthalimide), hexabromobenzene, and decabromodiphenyl ether. Examples of flame retardants include antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonophosphate pyroantimonate, tin dioxide, zinc metaborate, aluminum hydroxide, magnesium hydroxide, zirconium oxide, molybdenum oxide, red phosphorus compounds, ammonium polyphosphates, melamine cyanurate, and tetrafluoroethylene.

[0054] Furthermore, the resin composition of the present invention can be mixed with various additives according to the purpose. Examples of additives include known hindered phenolic, sulfur-based, phosphorus-based, and amine-based antioxidants; hindered amine, triazole, benzophenone, benzoate, nickel-based, and salicylic acid-based light stabilizers; antistatic agents; lubricants; peroxides and other molecular modifiers; compounds having reactive groups with epoxy compounds, carbodiimide compounds, etc.; metal passivators; organic and inorganic nucleating agents; neutralizing agents; acid resistant agents; antibacterial agents; fluorescent whitening agents; fillers; organic and inorganic pigments, etc. When these additives are mixed, the total amount of these additives is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, in the resin composition.

[0055] These additives can be mixed using mixers such as heated roll mills, extruders, and Banbury mills. Additionally, they can be added to or mixed with oligomers prior to transesterification or polycondensation reactions during the manufacture of thermoplastic polyester elastomers.

[0056] The resin composition of the present invention can be manufactured by mixing the above-mentioned components and, as needed, various stabilizers, pigments, etc., through melt mixing. The melt mixing method can be any method known to those skilled in the art, and can also use a single-screw extruder, a twin-screw extruder, a pressure kneader, a Banbury mixer, etc. A twin-screw extruder is preferred.

[0057] Furthermore, as described above, to ensure that reactive compounds such as polycarbodiimide come into contact with and react with the end groups of the thermoplastic polyester elastomer, it is preferable not to mix all components simultaneously, but to pre-add the reactive compounds to a portion of the thermoplastic polyester elastomer. On the other hand, the remaining thermoplastic polyester elastomer is pre-mixed and melted with additives, and the thermoplastic polyester elastomer containing the reactive mixture is fed into this melt via a side feeder. Using this feeding method, the reactive compounds do not adhere to the manufacturing apparatus, and loss of the reactive compounds during feeding is also prevented.

[0058] The thermoplastic polyester elastomer with end groups capped in this invention and the resin composition containing therein are composed as described above. They not only have excellent heat resistance, weather resistance, heat aging resistance, water resistance, and low temperature characteristics, but also excellent extrusion molding properties and extrusion molding stability. Therefore, hollow molded products with uniform length dimensions, such as cables and hoses, can be produced stably and for a long time through extrusion molding with uniform thickness.

Example

[0059] The present invention will be specifically described below with reference to examples and comparative examples. The present invention is not limited to the following examples, and may be modified within the appropriate scope depending on the context, all of which are included within the technical scope of the present invention. Furthermore, the various measurements in this specification are performed according to the following methods.

[0060] (1) Melting point (Tm) of thermoplastic polyester elastomer Thermoplastic polyester elastomers dried under reduced pressure at 50°C for 15 hours were heated from room temperature to the melting point (Tm) using a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation) at a rate of 20°C / min. The endothermic peak temperature was measured. Additionally, 10 mg of a sample (manufactured by Ta Instruments, product number 900793.901) was weighed into an aluminum dish, sealed with an aluminum cap (manufactured by Ta Instruments, product number 900794.901), and measured under an argon atmosphere.

[0061] (2) Reduced viscosity of thermoplastic polyester elastomer 0.05 g of thermoplastic polyester elastomer was dissolved in 25 mL of mixed solvent (phenol / tetrachloroethane = 60 / 40), and the reduced viscosity was measured at 30 °C using an Orstau viscometer.

[0062] (3) Acid value Dissolve 0.5 g of thermoplastic polyester elastomer in 100 mL of benzyl alcohol / chloroform (mass ratio 50 / 50), and determine the acid value by titration with an ethanolic solution of KOH. Phenol red is used as the indicator. The acid value is expressed as equivalents (eq / ton) in 1 ton of resin.

[0063] (4) Melt viscosity The melt viscosity of the thermoplastic polyester elastomer was measured using a "Capilograph 1D" manufactured by Toyo Seiki Co., Ltd. Specifically, the melt viscosity was measured at shear rates of 10 / s and 1000 / s after a preheating time of 5 minutes under conditions of a capillary diameter of 1.0 mm, a length of 40 mm, a barrel diameter of 9.55 mm, and a temperature of 230°C.

[0064] (5) Retention stability of melt viscosity Similar to the melt viscosity determination, the melt viscosity was measured after a preheating time of 5 minutes at a shear rate of 10 / second, denoted as η5. Furthermore, the melt viscosity was measured after a preheating time of 25 minutes at a shear rate of 10 / second, denoted as η25. The ratio η5 / η25 was calculated as the retention stability of the melt viscosity. The closer this ratio is to 1, the better the retention stability.

[0065] (6) Extrusion molding properties Extrusion formability is evaluated from the aspects of variation in discharge volume and thickness uniformity. [Extrusion Formability (Variation in Discharge)] The granules, melt-blended using a twin-screw extruder, are then extruded again from a die using a single-screw extruder, producing 3mm diameter strands. Based on this condition, the extrusion formability (variation in discharge volume) is evaluated according to the following criteria. ○: The discharge volume remained unchanged, and the extrudability remained stable. △: When the tractor pulls at a constant speed, it is stable, but when it sags due to its own weight, a slight change in the discharge volume can be observed. ×: The discharge volume varies greatly and cannot be towed.

[0066] Extrusion molding properties (thickness uniformity) The granules, melt-blended using a twin-screw extruder, were extruded again through a T-die using a single-screw extruder to produce sheet-like products with a thickness of 0.2 mm. The thickness uniformity of this sheet-like product was measured using a micrometer (Model: ID-C125B, probe: ultra-hard Carbide (M2.5×0.45) with a spherical bottom) manufactured by Mitutoyo Corporation at a compressed air pressure of 0.1 MPa. The measurement points were 20 grids spaced 90 mm apart in a 450 mm × 450 mm area at the center of the sheet. Thickness uniformity was measured in two ways: initial and over time. Initial thickness uniformity was measured at 20 points on the sheet at the 5-minute mark of extrusion, and the maximum and minimum values ​​were calculated using the following formula. Furthermore, the thickness uniformity over time was calculated using the average maximum and average minimum values ​​of the 20 thicknesses at 5, 30, and 60 minutes after the start of extrusion, using the following formula. Evaluation was conducted according to the following criteria. Furthermore, the thickness uniformity over time is specifically referred to as "extrusion molding stability". Thickness uniformity = (maximum value - minimum value) / {(maximum value + minimum value) / 2} × 100 (%) ○: Thickness uniformity is less than 1%. △: Thickness uniformity is 1% to less than 3%. ×: Thickness uniformity is above 3%.

[0067] (7) Flame retardancy A flame-retardant polyester elastomer resin composition was obtained by mixing 0.5% by weight of pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.3% by weight of pentaerythritol tetra(3-lauryl thiopropionate), 0.5% by weight of 2-(3-tert-butyl-5-methyl-2-hydroxyphenyl)benzotriazole, 0.5% by weight of bisphenol A, and 0.3% by weight of triphenylphosphine into a thermoplastic polyester elastomer that had been dried under reduced pressure at 100°C for 8 hours. The above-mentioned thermoplastic polyester elastomer composition was injection molded into 1 / 32-foot test pieces according to UL-94 standard using an injection molding machine (manufactured by Yamashiro Seiki Co., Ltd., model-SAV) at a cylinder temperature (Tm+20°C). The flame retardancy of the test pieces obtained by the above method was evaluated according to UL-94. The burning time was the sum of the burning times of each of the five samples after two ignitions.

[0068] (8) Heat resistance and heat aging resistance After placing dumbbell-shaped No. 3 test pieces at 170°C for any given time, they were removed and their tensile elongation at break was determined according to JIS K6251:2010. The retention rate of tensile elongation at break was calculated using the following formula, and the time it took for this retention rate to reach 50% (tensile elongation half-life) was used as an indicator of heat resistance and heat aging resistance. Furthermore, the initial tensile elongation at break is the tensile elongation at break before the heat resistance and heat aging resistance tests. Tensile elongation at break retention rate (%) = Tensile elongation at break after heat resistance and heat aging tests / Initial tensile elongation at break × 100 ○: Tensile elongation half-life is over 800 hours △: Tensile elongation half-life is 400 to less than 800 hours ×: Tensile elongation half-life less than 400hr Furthermore, the aforementioned dumbbell-shaped No. 3 test piece was made by injection molding a resin (manufactured by Yamashiro Seiki Co., Ltd., model-SAV) that had been dried under reduced pressure at 100°C for 8 hours, at a cylinder temperature of (Tm+20°C) and a metal mold temperature of 30°C, into a flat plate of 100mm×100mm×2mm, and then punching out the dumbbell-shaped No. 3 test piece from this flat plate.

[0069] The mixed raw materials used in the examples and comparative examples are as follows. Thermoplastic polyester elastomer Friday's thermoplastic polyester elastomer is used to manufacture the following four products, A-1 to A-4. Thermoplastic polyester elastomer A-1: 100 parts by mass of aliphatic polycarbonate diol (UH-CARB200 carbonate diol manufactured by Ube Industries, Inc., number average molecular weight 2000, 1,6-hexanediol type) and 8.6 parts by mass of diphenyl carbonate were added separately and reacted at 205°C and 130 Pa. After 2 hours, the contents were cooled to obtain aliphatic polycarbonate diol with increased molecular weight (number average molecular weight 10000). 43 parts by mass of this aliphatic polycarbonate diol (PCD) and 57 parts by mass of polybutylene terephthalate (PBT) with a number average molecular weight of 30000 were stirred at 230°C–245°C and 130 Pa for 1 hour until the resin became transparent. The contents were then removed, cooled, and thermoplastic polyester elastomer A-1 was obtained. The thermoplastic polyester elastomer A-1 has a melting point of 207°C, a reducing viscosity of 1.21 dl / g, and an acid value of 44 eq / ton. The composition and properties of the obtained thermoplastic polyester elastomer A-1 are shown in Table 1.

[0070] Thermoplastic polyester elastomer A-2: In addition to its use in the copolymerization of trimethylolpropane for branching, thermoplastic polyester elastomer A-2 was synthesized in the same manner as thermoplastic polyester elastomer A-1. Specifically, 100 parts by mass of aliphatic polycarbonate diol (UH-CARB200 carbonate diol manufactured by Ube Industries, Inc., number average molecular weight 2000, 1,6-hexanediol type) and 8.6 parts by mass of diphenyl carbonate were separately added and reacted at 205°C and 130 Pa. After 2 hours, the contents were cooled to obtain aliphatic polycarbonate diol with increased molecular weight (number average molecular weight 10000). 43 parts by mass of the aliphatic polycarbonate diol (PCD), 57 parts by mass of polybutylene terephthalate (PBT) with a number-average molecular weight of 30,000, and 0.0005 parts by mass of trimethylolpropane for branching were stirred at 230°C–245°C and 130 Pa for 1 hour until the resin became transparent. The contents were then removed and cooled to obtain thermoplastic polyester elastomer A-2. Thermoplastic polyester elastomer A-2 has a melting point of 214°C, a reducing viscosity of 1.38 dl / g, and an acid value of 39 eq / ton. The composition and properties of the obtained thermoplastic polyester elastomer A-2 are shown in Table 1.

[0071] Thermoplastic polyester elastomer A-3: For comparative purposes, a thermoplastic polyester elastomer A-3 was synthesized, whose soft segment was not an aliphatic polycarbonate diol but an aliphatic polyether. Specifically, using the same method as described above, a thermoplastic polyester elastomer A-3 was obtained with a hard segment (polybutylene terephthalate) / soft segment (PTMG) ratio of 56 / 44 (wt%), consisting of terephthalic acid, 1,4-butanediol, and polyoxytetramethylene glycol (PTMG; number average molecular weight 1000). This thermoplastic polyester elastomer A-3 had a melting point of 203°C, a reducing viscosity of 1.75 dl / g, and an acid value of 50 eq / ton. The composition and properties of the obtained thermoplastic polyester elastomer A-3 are shown in Table 1.

[0072] Thermoplastic polyester elastomer A-4: In addition to increasing the molecular weight of aliphatic polycarbonate diol, thermoplastic polyester elastomer A-4 was synthesized using the same method as thermoplastic polyester elastomer A-1. Specifically, 100 parts by mass of aliphatic polycarbonate diol (UH-CARB200 carbonate diol manufactured by Ube Industries, Inc., number average molecular weight 2000, 1,6-hexanediol type) and 9.6 parts by mass of diphenyl carbonate were separately added and reacted at 205°C and 130 Pa. After 2 hours, the contents were cooled to obtain aliphatic polycarbonate diol with increased molecular weight (number average molecular weight 20000). 43 parts by mass of this aliphatic polycarbonate diol (PCD) and 57 parts by mass of polybutylene terephthalate (PBT) with a number average molecular weight of 30000 were stirred at 230°C–245°C and 130 Pa for 1 hour. After confirming that the resin had become transparent, the contents were removed, cooled, and thermoplastic polyester elastomer A-4 was obtained. The thermoplastic polyester elastomer A-4 has a melting point of 207℃, a reduced viscosity of 1.25 dl / g, and an acid value of 49 eq / ton. The composition and physical properties of the obtained thermoplastic polyester elastomer A-4 are shown in Table 1.

[0073] Table 1 PBT: Polybutylene terephthalate PTMG: Polyoxytetramethylene Diol PCD: Aliphatic polycarbonate diol

[0074] [Reactive compounds] B-1: Alicyclic polycarbodiimide (CARBODILITE HMV-15CA, manufactured by Nisshinbo Chemical Co., Ltd.) B-2: Triglycidyl isocyanurate (TEPIC-S, manufactured by Nissan Chemical Co., Ltd., epoxy valence (average number of epoxy groups per molecule): 3) B-3: Styrene / glycidyl acrylate copolymer (ARUFON UG-4050, manufactured by Dong-A Synthetic Co., Ltd., Mw: 8500, epoxy value: 670 equivalents / 1×10 6 g) B-4: An olefin copolymer containing epoxy groups (BONDFAST BF-7M, manufactured by Sumitomo Chemical Co., Ltd., epoxy value: 0.4 meq / g)

[0075] Flame retardants C-1: Brominated polystyrene (PDBS-80, manufactured by Lanxess). C-2: Antimony trioxide (PATOX MK, manufactured by Nippon Minerals Co., Ltd.)

[0076] Other additives D-1: Release agent LICOWAX E (manufactured by AZ Electronic Materials (Japan) Co., Ltd.), 0.2 parts by weight D-2: Hindered phenolic antioxidant Irganox 1010 (manufactured by BASF), 0.5 parts by weight D-3: Hindered phenolic antioxidant Irganox 1098 (manufactured by BASF), 0.2 parts by weight D-4: Aromatic amine antioxidant Nonflex DCD (manufactured by Seiko Chemical Co., Ltd.), 0.8 parts by weight D-5: Lasumit LG, a sulfur-based antioxidant (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), 0.2 parts by weight

[0077] [Examples 1-10, Comparative Examples 1-7] The aforementioned thermoplastic polyester elastomer, reactive compound, flame retardant, and other additives were mixed according to the mixing ratios and reactive compound addition methods shown in Table 2 to obtain a thermoplastic polyester elastomer resin composition. Furthermore, in Table 2, the resin proportions representing the mixing ratios refer to parts by weight. The properties of the obtained thermoplastic polyester elastomer resin composition were evaluated. The results are shown in Table 2. The detailed methods for adding the reactive compound (Method A and Method B) in Table 2 are described below. Method A: Add 3 parts by weight of a reactive compound to the thermoplastic polyester elastomer and feed it into the molten resin composition from a side feeder. Method B: The reactive compound is premixed with other ingredients and fed into the hopper together.

[0078] Table 2

[0079] As shown in Table 2, in any of Examples 1 to 10 that meet the conditions of the present invention, the variation in discharge amount during extrusion molding is small, the initial thickness uniformity is excellent, and the extrusion moldability is excellent. Furthermore, the thickness uniformity over time is also excellent, and the extrusion molding stability is also excellent. In addition, the heat resistance and heat aging resistance, which are essential properties for thermoplastic polyester elastomers, are also excellent. In particular, Example 9, despite the addition of a flame retardant, still exhibits stable extrusion moldability, extrusion molding stability, heat resistance, and heat aging resistance. In Comparative Example 1, the mixing ratio of the reactive compound was the same as in Example 1. However, because the reactive compound was added along with other components, the end groups of the thermoplastic polyester elastomer were not sufficiently capped by the reactive compound, thus failing to adequately reduce the acid value and resulting in poor retention stability of its melt viscosity. Consequently, it increased in viscosity over time, and its thickness varied, leading to poor extrusion molding stability. Furthermore, its heat resistance and heat aging resistance were also poor. In Comparative Example 2, due to the excessive mixing of reactive compounds, unreacted reactive compounds remained, leading to gelation and increased viscosity. This resulted in unstable melt viscosity and unstable extrusion formability at the initial stage of molding. Furthermore, the inclusion of reactive compounds alongside other components easily caused localized thickening, deteriorating melt viscosity retention stability. Consequently, the mixture thickened over time, exhibited variations in thickness, and exhibited poor extrusion stability. In Comparative Example 3, the reactive compound, lacking the highly effective polycarbodiimide (B-1) for reducing acid value, failed to adequately lower the acid value, resulting in poor heat resistance and heat aging resistance. Furthermore, the glycidyl-based compound (B-3) used as the reactive compound caused viscosity increases over time, which offset the deterioration in melt viscosity retention stability due to the high acid value. The melt viscosity retention stability was close to 1. Although the apparent variation in melt viscosity was small, the thickness changed over time, leading to poor extrusion molding stability. In Comparative Example 4, since the reactive compound, polycarbodiimide (B-1), which has an excellent effect on reducing acid value, was almost absent, although other aspects were the same as in Example 1, it could not sufficiently reduce the acid value, resulting in poor heat resistance and heat aging resistance. Furthermore, the glycidyl-based compound (B-2) used as the reactive compound caused viscosity increase over time, which offset the deterioration in melt viscosity retention stability caused by the high acid value. The melt viscosity retention stability was close to 1. Although the change in melt viscosity appeared small, the thickness changed over time, resulting in poor extrusion molding stability. In Comparative Example 5, due to the large amount of polyfunctional epoxy compound (B-3) added, a thermoplastic polyester elastomer with high molecular weight and multiple branches was obtained. It had high melt viscosity at high shear rates and poor thickness uniformity in the early stage of molding. In Comparative Example 6, although a non-branched thermoplastic polyester elastomer was used in the same way as in Example 3, unlike in Example 3, due to the absence of the trifunctional epoxy compound (B-2), the melt viscosity at low shear rates was low, the shape retention was poor, the thickness was unstable over time, and the extrusion molding properties were poor. In Comparative Example 7, since the soft segment is not an aliphatic polycarbonate but an aliphatic polyether, although other aspects are the same as in Example 1, the heat resistance and heat aging resistance are poor. [Industry Applicability]

[0080] The thermoplastic polyester elastomer of this invention not only meets the basic performance requirements for automotive and home appliance components, such as heat resistance, weather resistance, heat aging resistance, and low-temperature characteristics, but also, due to its excellent extrusion moldability and stability, can stably produce hollow and long-sized molded products such as cables or hoses with uniform thickness over long periods of time through extrusion molding. Therefore, this invention greatly contributes to the industry.

Claims

1. A thermoplastic polyester elastomer, characterized in that, It is composed of hard segments and soft segments bonded together. The hard segments are composed of polyesters consisting of aromatic dicarboxylic acids and aliphatic or alicyclic diols, and the soft segments are mainly composed of aliphatic polycarbonate. At least a portion of the terminal groups of the thermoplastic polyester elastomer are capped by a reactive compound, which contains 0.3, 0.5 to 5 parts by mass of polycarbodiimide relative to 100 parts by mass of the thermoplastic polyester elastomer. Relative to 100 parts by weight of thermoplastic polyester elastomer, the compound contains 0 to 4.5 parts by weight of a reactive compound having at least one functional group selected from glycidyl groups, anhydride groups, and isocyanate groups as a reactive compound. The thermoplastic polyester elastomer is manufactured by pre-adding reactive compounds to a portion of the thermoplastic polyester elastomer; The acid value of the thermoplastic polyester elastomer is below 15 eq / ton. According to JIS K7199, when the melt viscosity of the thermoplastic polyester elastomer is measured at 230°C, the following conditions (i) and (ii) must be met: (i) The melt viscosity is above 1800 Pa·s when the preheating time is 5 minutes and the shear rate is 10 / second, and the melt viscosity is below 800 Pa·s when the preheating time is 5 minutes and the shear rate is 1000 / second; (ii) The ratio of melt viscosity at a shear rate of 10 / s, measured at preheating times of 5 minutes and 25 minutes, is 0.7 to 1.

3.

2. The thermoplastic polyester elastomer according to claim 1, characterized in that, The reactive compound contains 0.5 to 1.2 parts by mass of polycarbodiimide relative to 100 parts by mass of thermoplastic polyester elastomer.

3. The thermoplastic polyester elastomer according to claim 1, characterized in that, The reactive compound comprises, relative to 100 parts by weight of thermoplastic polyester elastomer, 0.1 to 3 parts by weight of a reactive compound having at least one functional group selected from glycidyl group, acid anhydride group and isocyanate group.

4. A resin composition, characterized in that, It contains the thermoplastic polyester elastomer and flame retardant as described in any one of claims 1 to 3.

5. A molded article, characterized in that, It is obtained by extrusion molding of the thermoplastic polyester elastomer according to any one of claims 1 to 3 or the resin composition according to claim 4.

6. The molded article according to claim 5, characterized in that, The molded product is a cable or hose.

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