Polyester elastomer resin composition

Abstract

The present invention is a polyester elastomer resin composition that has excellent extrusion moldability and surface smoothness even in a thin shape while maintaining mechanical properties and has excellent flame retardancy and heat aging resistance / hydrolysis resistance without containing a halogen, wherein the polyester elastomer resin composition contains a polyester elastomer (A) and a phosphorus flame retardant (B), the polyester elastomer (A) consists of a hard segment comprising a polyester and at least one soft segment selected from an aliphatic polyether, an aliphatic polyester, and an aliphatic polycarbonate, the surface hardness is Shore D 55 or lower, the phosphorus flame retardant (B) has an average particle size D50 of 20 μm or lower and a phosphorus concentration of 15 mass% or higher, and the polyester elastomer resin composition contains 5-50 mass parts of the phosphorus flame retardant (B) and, if needed, a predetermined amount of an acid end capping agent (C) relative to 100 mass parts of the polyester elastomer (A), and has an acid value of 10 eq / ton or lower.

Description

[Technical field]

[0001] The present invention relates to a polyester elastomer composition that has excellent extrusion moldability and surface smoothness even in a thin-walled shape while maintaining mechanical properties, and that is halogen-free and has excellent flame retardancy, heat aging resistance, and hydrolysis resistance. [Background technology]

[0002] In recent years, the replacement of metal and rubber parts with thermoplastic resins has been promoted in automobiles and home appliances. In addition, as automobiles and home appliances become more powerful, the distance between parts is getting closer, and the opportunities for resin parts to be exposed to ultra-high temperatures are increasing. Due to these development trends, there is a strong demand for the development of resin compositions that are both heat-resistant and flame-retardant.

[0003] To meet these demands, thermoplastic polyester elastomers such as polyether ester type, polyester ester type, and polycarbonate ester type are known to have excellent heat aging resistance and mechanical properties.

[0004] The most popular method for improving the flame retardancy of thermoplastic resins, including thermoplastic polyester elastomers, is to add halogen-based flame retardants. However, because such thermoplastic polyester elastomers using halogen compounds generate toxic gases when burned, the use of halogen compounds has been restricted in recent years from the viewpoint of environmental protection. Therefore, it is considered ideal to improve the flame retardancy of thermoplastic polyester elastomers without using halogen-based flame retardants.

[0005] In order to meet these demands, a method has recently been proposed in which a specific metal hydrate is blended as an inorganic flame retardant, which can suppress the combustion of the resin by undergoing decomposition and dehydration reactions through endothermic reactions at the combustion temperature of the resin. However, the metal hydrate used in this method has an extremely weak flame retardant effect, so it is necessary to blend a large amount of it in order to achieve a flame retardant effect. As a result, problems such as a decrease in the molding processability of the resulting flame-retardant resin composition and a decrease in the mechanical strength of the resulting molded product arise.

[0006] In recent years, in order to meet the above demands, methods have been proposed that use specific phosphorus compounds, such as a fire prevention material that combines ethylenediamine phosphate with a salt of melamine and / or a cyanuric acid derivative, such as melamine phosphate (Patent Document 1), and a flame-retardant thermoplastic resin composition that contains a phosphate such as an alkyldiamine phosphate as a flame retardant (Patent Document 2).

[0007] Intumescent flame retardants have also been disclosed, which form a surface intumescent layer during combustion and suppress the diffusion and heat transfer of decomposition products, thereby exerting flame retardancy (Patent Document 3). However, these phosphorus-based flame retardants are poor in flame retardancy-imparting effect compared to halogen-based flame retardants, and require the addition of large amounts, so that in polyester elastomers, they are still not sufficient in terms of achieving both high flame retardancy and other properties (mechanical properties, heat aging resistance, and hydrolysis resistance).

[0008] Furthermore, in applications such as tubes and wire coating, where extrusion molding is unavoidable, there have been occasional problems with the addition of large amounts of flame retardants, resulting in poor appearance of the molded product, and there have also been issues with balancing with product quality. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 50-107044 [Patent Document 2] Japanese Patent Publication No. 50-109946 [Patent Document 3] Japanese Patent Application Publication No. 59-47285 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been devised in view of the current state of the prior art, and its object is to provide a flame-retardant polyester elastomer composition which has excellent extrusion moldability and surface smoothness even in a thin-walled shape while maintaining mechanical properties, and which is halogen-free and has excellent flame retardancy, heat aging resistance, and hydrolysis resistance. [Means for solving the problem]

[0011] In order to achieve the above object, the present inventors have conducted extensive research into flame-retardant polyester elastomer compositions that do not contain halogen compounds, and have finally completed the present invention.

[0012] That is, the present invention is as follows. [1] A polyester elastomer resin composition containing a polyester elastomer (A) and a phosphorus-based flame retardant (B), The polyester elastomer (A) is composed of a hard segment made of a polyester having an aromatic dicarboxylic acid and an aliphatic or alicyclic diol as constituent components, and at least one soft segment selected from an aliphatic polyether, an aliphatic polyester, and an aliphatic polycarbonate, and has a surface hardness of Shore D55 or less; The phosphorus-based flame retardant (B) has an average particle size D50 of 20 μm or less and a phosphorus concentration of 15 mass% or more, A polyester elastomer resin composition having an acid value of 10 eq / ton or less, comprising 5 to 50 parts by mass of the phosphorus-based flame retardant (B) relative to 100 parts by mass of the polyester elastomer (A), and further comprising, as an acid end-blocking agent (C), 0 to 5 parts by mass of an epoxy compound (C-1) or 0 to 1.5 parts by mass of a carbodiimide compound (C-2).

[0013] [2] The polyester elastomer resin composition according to [1], wherein the hard segment of the polyester elastomer (A) is a polyester having terephthalic acid and 1,4-butanediol as constituent components, the soft segment is an aliphatic polycarbonate diol, and the polyester elastomer (A) has a melting point of 150 to 230°C.

[0014] [3] The polyester elastomer resin composition according to [1] or [2], wherein the phosphorus-based flame retardant (B) is a metal phosphinate, a (poly)phosphate, or both.

[0015] [4] The polyester elastomer resin composition according to any one of [1] to [3], further comprising 0.1 to 3 parts by mass of an amide-based lubricant (D) per 100 parts by mass of the polyester elastomer (A).

[0016] [5] The polyester elastomer resin composition according to any one of [1] to [4], which is for use in cable coating. Effect of the Invention

[0017] The flame-retardant polyester elastomer resin composition of the present invention has excellent extrusion moldability and surface smoothness even in thin-walled shapes while maintaining mechanical properties, and is halogen-free and can achieve both excellent flame retardancy and heat aging resistance / hydrolysis resistance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] [Polyester elastomer (A)] The polyester elastomer (A) used in the present invention is composed of a hard segment and a soft segment. The hard segment is composed of a polyester. The aromatic dicarboxylic acid constituting the polyester of the hard segment is not particularly limited, and is generally a typical aromatic dicarboxylic acid. However, it is preferable that the main aromatic dicarboxylic acid is terephthalic acid or naphthalenedicarboxylic acid (among isomers, 2,6-naphthalenedicarboxylic acid is preferable). Of all dicarboxylic acids constituting the polyester of the hard segment, terephthalic acid or naphthalenedicarboxylic acid is preferably 70 mol% or more, more preferably 80 mol% or more. Examples of other dicarboxylic acid components include aromatic dicarboxylic acids such as diphenyldicarboxylic acid, isophthalic acid, and 5-sodium sulfoisophthalic acid, 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, dodecanedioic acid, dimer acid, and hydrogenated dimer acid. These are used in an amount that does not significantly lower the melting point of the resin, and the amount is preferably 30 mol % or less, more preferably 20 mol % or less, of the total acid components.

[0019] In the polyester elastomer (A) used in the present invention, the aliphatic or alicyclic diol constituting the polyester of the hard segment is generally aliphatic or alicyclic diol, and 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, and 1,4-cyclohexanedimethanol. Among these, ethylene glycol or 1,4-butanediol is preferable in terms of imparting heat resistance.

[0020] As the component constituting the polyester of the above hard segment, a butylene terephthalate unit (a unit consisting of terephthalic acid and 1,4-butanediol) or a butylene naphthalate unit (a unit consisting of 2,6-naphthalenedicarboxylic acid and 1,4-butanediol) is preferred from the viewpoints of physical properties, moldability, and cost performance.

[0021] In addition, when an aromatic polyester suitable as a polyester constituting a hard segment in the polyester elastomer (A) used in the present invention is produced in advance and then copolymerized with a soft segment component, the aromatic polyester can be easily obtained according to a normal polyester production method. In addition, such a polyester preferably has a number average molecular weight of 10,000 to 40,000.

[0022] The soft segment of the polyester elastomer (A) used in the present invention is at least one selected from aliphatic polyethers, aliphatic polyesters, and aliphatic polycarbonates. Examples of aliphatic polyethers include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, poly(trimethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, ethylene oxide adducts of poly(propylene oxide) glycol, copolymers of ethylene oxide and tetrahydrofuran, etc. Among these, poly(tetramethylene oxide) glycol and ethylene oxide adducts of poly(propylene oxide) glycol are preferred in terms of elasticity properties.

[0023] Examples of aliphatic polyesters include poly(ε-caprolactone), polyenantholactone, polycaprylolactone, polybutylene adipate, etc. Among these, poly(ε-caprolactone) and polybutylene adipate are preferred in terms of elasticity characteristics.

[0024] The aliphatic polycarbonate is preferably composed mainly of an aliphatic diol residue having 2 to 12 carbon atoms. Examples of these aliphatic diols include ethylene glycol, 1,3-propylene glycol, 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. In particular, aliphatic diols having 5 to 12 carbon atoms are preferred in terms of flexibility and low-temperature properties of the resulting thermoplastic polyester elastomer. These components may be used alone or in combination of two or more kinds as necessary, based on the examples described below.

[0025] The aliphatic polycarbonate diol having good low-temperature properties and constituting the soft segment of the polyester elastomer in the present invention preferably has a low melting point (for example, 70°C or less) and a low glass transition temperature. In general, the aliphatic polycarbonate diol made of 1,6-hexanediol used to form the soft segment of the polyester elastomer has a low glass transition temperature of about -60°C and a melting point of about 50°C, so that it has good low-temperature properties. In addition, an aliphatic polycarbonate diol obtained by copolymerizing, for example, an appropriate amount of 3-methyl-1,5-pentanediol with the above aliphatic polycarbonate diol has a slightly higher glass transition point than the original aliphatic polycarbonate diol, but has a lower melting point or is amorphous, so that it corresponds to an aliphatic polycarbonate diol having good low-temperature properties. For example, an aliphatic polycarbonate diol made of 1,9-nonanediol and 2-methyl-1,8-octanediol has a melting point of about 30° C. and a glass transition temperature of about −70° C., which are sufficiently low, and therefore corresponds to an aliphatic polycarbonate diol with good low-temperature properties.

[0026] As the soft segment of the polyester elastomer (A), an aliphatic polycarbonate diol is preferred from the viewpoint of heat aging resistance of the polyester elastomer resin composition.

[0027] It is an absolute requirement that the polyester elastomer (A) used in the present invention has a Shore D hardness of 55D or less. Therefore, the mass ratio of hard segments to soft segments (hard segment:soft segment) is generally preferably in the range of 10:90 to 75:25, more preferably 15:85 to 70:30, even more preferably 20:80 to 65:35, particularly preferably 40:60 to 65:35, and most preferably 45:55 to 60:40.

[0028] Generally, in thermoplastic polyester elastomers, the higher the hard segment ratio, the better the flame retardancy, but on the other hand, a high hard segment ratio is synonymous with having a high material hardness, and if the material hardness is too high, the mechanical properties and durability will be significantly reduced due to the addition of a flame retardant. Therefore, the mass ratio of hard segments to soft segments in the polyester elastomer is preferably within the above-mentioned range, and the Shore D hardness must be 55D or less. The Shore D hardness is preferably 53D or less, and more preferably 51D or less. There is no particular limit to the lower limit of the Shore D hardness, but it is preferably 30D or more.

[0029] The reduced viscosity of the polyester elastomer (A) used in the present invention is preferably from 1.0 to 2.5 dl / g, and more preferably from 1.0 to 2.0 dl / g.

[0030] The polyester elastomer (A) used in the present invention can be produced by a known method, for example, a method of transesterifying a lower alcohol diester of a dicarboxylic acid, an excess amount of a low molecular weight glycol, and a soft segment component in the presence of a catalyst, and polycondensing the resulting reaction product, a method of esterifying a dicarboxylic acid, an excess amount of a glycol, and a soft segment component in the presence of a catalyst, and polycondensing the resulting reaction product, a method of preparing a hard segment polyester in advance, adding a soft segment component to the polyester, and randomizing the polyester by transesterification, a method of connecting a hard segment and a soft segment with a chain linking agent, and further, when poly(ε-caprolactone) is used for the soft segment, an addition reaction of an ε-caprolactone monomer to the hard segment, or any other method may be used.

[0031] [Phosphorus-based flame retardants (B)] Generally, phosphorus-based flame retardants include organic phosphorus compounds and inorganic phosphorus compounds. The phosphorus-based flame retardant (B) used in the present invention is roughly divided into organic phosphorus compounds and inorganic phosphorus compounds. Examples of organic phosphorus compounds include phosphates, phosphonates, phosphinates, and phosphites, specifically trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, octyl diphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, triphenyl phosphate, trixylenyl phosphate, tris-isopropylphenyl phosphate, diethyl-N,N-bis(2-hydroxyethyl)aminomethylphosphonate, and bis(1,3-phenylenediphenyl)phosphate. Among them, from the viewpoint of flame retardancy, metal phosphinate is preferred, and aluminum phosphinate is particularly preferred. Examples of inorganic phosphorus compounds include red phosphorus compounds and inorganic phosphate compounds such as ammonium (poly)phosphate, melamine (poly)phosphate, and piperazine (poly)phosphate. In some industries, organic phosphorus compounds may be restricted, and in such cases, inorganic phosphorus compounds must be used. Among inorganic phosphorus compounds, polyphosphate compounds are preferred. Types of polyphosphate compounds include orthophosphate, which is a monomer, and condensed phosphates in which orthophosphate is polymerized by dehydration reaction. Condensed phosphates include pyrophosphate, metaphosphate, and polyphosphate. In other words, the term "polyphosphate compound" refers to one or more compounds selected from orthophosphate compounds, pyrophosphate compounds, metaphosphate compounds, and polyphosphate compounds. Any of the (poly)phosphate compounds may be used, but from the viewpoint of exhibiting high flame retardancy, a lower molecular weight compound is more preferred, and from the viewpoint of suppressing the bleeding out of phosphorus-based flame retardants and dissolution during immersion in water, a higher molecular weight compound is more preferred. Therefore, among the (poly)phosphate compounds, pyrophosphate compounds are preferred. The (poly)phosphate compound may be a single (poly)phosphate compound or a composite flame retardant containing two or more (poly)phosphate compounds.The properties (flame retardancy and thermal stability) of the (poly)phosphate compound are derived from the chemical structure of its counter ion, and each counter ion has its own unique features. For example, (poly)ammonium phosphate has excellent flame retardancy but poor processing stability, whereas (poly)melamine phosphate has excellent processing stability but poor flame retardancy. By using a composite flame retardant containing two or more (poly)phosphate compounds, a composition having a good balance of multiple properties such as flame retardancy and processing stability can be obtained. In particular, using a composite flame retardant consisting of (poly)melamine phosphate and (poly)piperazine phosphate as the phosphorus-based flame retardant (B) is a preferred embodiment, since it can provide a composition having a better balance of flame retardancy and processing stability (i.e., mechanical properties). Using a composite flame retardant consisting of melamine pyrophosphate and piperazine pyrophosphate as the phosphorus-based flame retardant (B) is a more preferred embodiment.

[0032] As the phosphorus-based flame retardant (B), a phosphorus-based flame retardant having an average particle size D50 of 20 μm or less and a phosphorus concentration of 15 mass% or more can be used. Regarding the average particle size D50, if a large particle size is used, the surface smoothness of the extrusion molded product tends to deteriorate. Regarding the phosphorus concentration, a flame retardant with a low phosphorus concentration tends to have a poor flame retardant effect, so a large amount must be added, making it difficult to achieve both flame retardancy and other properties. The average particle size D50 can be measured and analyzed using a laser diffraction particle size distribution meter, and the phosphorus concentration can be measured (calculated) using ICP emission spectrometry. The average particle size D50 is preferably 16 μm or less, more preferably 12 μm or less. The lower limit of the average particle size D50 is not particularly limited, but is preferably 0.1 μm or more. The phosphorus concentration is preferably 18 mass% or more, more preferably 20 mass% or more. The upper limit of the phosphorus concentration is not particularly limited, but is preferably 30 mass% or less.

[0033] The content of the phosphorus-based flame retardant (B) is 5 to 50 parts by mass, preferably 8 to 40 parts by mass, more preferably 10 to 35 parts by mass, and particularly preferably 15 to 30 parts by mass, relative to 100 parts by mass of the polyester elastomer (A). If the content of the phosphorus-based flame retardant (B) is less than 5 parts by mass, the flame retardancy is insufficient, whereas if the content exceeds 50 parts by mass, problems such as a decrease in mechanical properties arise.

[0034] The polyester elastomer resin composition of the present invention may contain a non-halogen flame retardant other than the phosphorus-based flame retardant as necessary. Examples of the non-halogen flame retardant other than the phosphorus-based flame retardant include nitrogen-based flame retardants, silicon-based flame retardants, metal hydroxides, and metal borates.

[0035] [Acid end-capping agent (C)] The acid end-capping agent (C) used in the present invention is a compound having a functional group capable of reacting with the terminal carboxyl group of the polyester elastomer (A). Examples of the functional group capable of reacting with the terminal carboxyl group of the polyester elastomer (A) include an epoxy group, a hydroxyl group, a carbodiimide group, and an oxazoline group. Among these, the functional group of the acid end-capping agent (C) is preferably an epoxy group or a carbodiimide group in view of the change in melt viscosity during melt retention and the reactivity with the terminal carboxyl group of the polyester elastomer. Therefore, the acid end-capping agent (C) is preferably an epoxy compound (C-1) and / or a carbodiimide compound (C-2). Note that, as described later, the acid end-capping agent (C) does not necessarily need to be blended as long as the acid value of the polyester elastomer resin composition satisfies 10 eq / ton or less, and the blending amount (content) may be 0.

[0036] Examples of the epoxy compound (C-1) include aliphatic epoxy compounds such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and diglycerin tetraglycidyl ether; dicyclopentadiene dioxide; and epoxycyclohexene carbamide. Examples of epoxy compounds include alicyclic epoxy compounds such as ethylene glycol diepoxy esters of polyphenols, 3,4-epoxycyclohexenylmethyl-3'-4'-epoxycyclohexenecarboxylate and 1,2:8,9-diepoxylimonene, bisphenol F diepoxy compounds, epoxy compounds obtained by reacting polyphenol compounds with epichlorohydrin and hydrogenated compounds thereof, aromatic or heterocyclic epoxy compounds such as diglycidyl phthalate and triglycidyl isocyanurate, compounds having an epoxy group at the terminal of a silicone oil, and compounds having an alkoxysilane and an epoxy group.

[0037] As the epoxy compound (C-1), a diepoxy compound is preferable from the viewpoint of reaction control and extrusion moldability. Monoepoxy compounds do not have the effect of chain extension and are poor in the effect of imparting extrusion moldability. In addition, many of them have a low volatilization temperature, and gas during molding may become a problem. In addition, epoxy compounds with three or more functionalities may have a large effect of imparting melt viscosity, but may be difficult to control the reaction and maintain fluidity.

[0038] As the epoxy compound (C-1), a bisphenol F diepoxy compound is preferred. Compared with other epoxy compounds, bisphenol F epoxy compounds have an excellent balance between epoxy equivalent and low volatility, so that they are less likely to cause problems such as decomposition gas and associated poor appearance while maintaining reactivity with the terminal carboxyl group of the polyester elastomer. Furthermore, for those that are liquid under normal temperature and pressure conditions, they have the advantage that they easily exhibit bending fatigue while maintaining fluidity because they simultaneously exhibit a plasticizing effect while producing a chain extension effect, and it is preferable to use these compounds. As such epoxy compounds, Epicron 830 manufactured by DIC Corporation, jER4004P, jER4005P, jER4010P manufactured by Mitsubishi Chemical Corporation, and the like can be used.

[0039] The content of the epoxy compound (C-1) is 0 to 5 parts by mass per 100 parts by mass of the polyester elastomer (A). When the epoxy compound (C-1) is added to the polyester elastomer (A), the content is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the polyester elastomer (A). This component is added for the purpose of improving hydrolysis resistance and improving flex fatigue resistance by chain extension, but if it is less than 0.1 part by mass, the improving effects are insufficient, while if it exceeds 5 parts by mass, there are cases in which a decrease in flame retardancy or a decrease in mechanical properties due to a foreign matter effect occurs.

[0040] The carbodiimide compound (C-2) used in the present invention is a compound having at least one carbodiimide group represented by (-N=C=N-) in the molecule, and capable of reacting with the terminal group of a polyester elastomer.

[0041] Examples of the carbodiimide compound (C-2) include diphenylcarbodiimide, di-cyclohexylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, diisopropylcarbodiimide, dioctyldecylcarbodiimide, di-o-toluylcarbodiimide, di-p-toluylcarbodiimide, di-p-nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, di-p-hydroxyphenylcarbodiimide, di-p-chlorophenylcarbodiimide, di-o-chlorophenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, nylcarbodiimide, di-2,5-dichlorophenylcarbodiimide, p-phenylene-bis-o-toluylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, p-phenylene-bis-di-p-chlorophenylcarbodiimide, 2,6,2',6'-tetraisopropyldiphenylcarbodiimide, hexamethylene-bis-cyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, ethylene-bis-dicyclohexylcarbodiimide, N,N'-di-o-toluylcarbodiimide, N,N'-diphenyl N,N'-dioctyldecylcarbodiimide, N,N'-di-2,6-dimethylphenylcarbodiimide, N-toluyl-N'-cyclohexylcarbodiimide, N,N'-di-2,6-diisopropylphenylcarbodiimide, N,N'-di-2,6-di-tert-butylphenylcarbodiimide, N-toluyl-N'-phenylcarbodiimide, N,N'-di-p-nitrophenylcarbodiimide, N,N'-di-p-aminophenylcarbodiimide, N,N'-di-p-hydroxyphenylcarbodiimide, N,N '-Di-cyclohexylcarbodiimide, N,N'-di-p-toluylcarbodiimide, N,N'-benzylcarbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N-octadecyl-N'-toluylcarbodiimide, N-cyclohexyl-N'-toluylcarbodiimide, N-phenyl-N'-toluylcarbodiimide, N-benzyl-N'-toluylcarbodiimide, N,N'-di-o-ethylphenylcarbodiimide, N,N'-di-p-ethylphenylcarbodiimide, N,Mono- or dicarbodiimide compounds such as N'-di-o-isopropylphenylcarbodiimide, N,N'-di-p-isopropylphenylcarbodiimide, N,N'-di-o-isobutylphenylcarbodiimide, N,N'-di-p-isobutylphenylcarbodiimide, N,N'-di-2,6-diethylphenylcarbodiimide, N,N'-di-2-ethyl-6-isopropylphenylcarbodiimide, N,N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, N,N'-di-2,4,6-trimethylphenylcarbodiimide, N,N'-di-2,4,6-triisopropylphenylcarbodiimide, and N,N'-di-2,4,6-triisobutylphenylcarbodiimide; poly(1,6-hexamethylenecarbodiimide); diimide), poly(4,4'-methylenebiscyclohexylcarbodiimide), poly(1,3-cyclohexylenecarbodiimide), poly(1,4-cyclohexylenecarbodiimide), poly(4,4'-diphenylmethanecarbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(toluylcarbodiimide), poly(diisopropylcarbodiimide), poly(methyl-diisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), and the like. Among these, N,N'-di-2,6-diisopropylphenylcarbodiimide, 2,6,2',6'-tetraisopropyldiphenylcarbodiimide, and polycarbodiimide are preferred, and more preferred are poly(1,6-hexamethylenecarbodiimide), poly(4,4'-methylenebiscyclohexylcarbodiimide), poly(1,3-cyclohexylenecarbodiimide), poly(1,4-cyclohexylenecarbodiimide), poly(4,4'-diphenylmethanecarbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(toluylcarbodiimide), poly(diisopropylcarbodiimide), poly(methyl-diisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), and other polycarbodiimides, with poly(1,4-cyclohexylenecarbodiimide) and poly(triisopropylphenylenecarbodiimide) being particularly preferred.

[0042] The content of the carbodiimide compound (C-2) is 0 to 1.5 parts by mass per 100 parts by mass of the polyester elastomer (A). When the carbodiimide compound (C-2) is added to the polyester elastomer (A), the content is preferably 0.1 to 1.5 parts by mass, more preferably 0.3 to 1.2 parts by mass, and even more preferably 0.5 to 1.0 parts by mass per 100 parts by mass of the polyester elastomer (A). If it is less than 0.1 part by mass, the hydrolysis resistance may be insufficient, and in some cases where a large amount of flame retardant is contained, problems such as low tensile elongation may occur. If it exceeds 1.5 parts by mass, a large amount of decomposition gas such as an isocyanate component is generated from the carbodiimide itself, which tends to impair the appearance of the extrusion molded product.

[0043] As the acid end blocking agent (C), either the epoxy compound (C-1) or the carbodiimide compound (C-2) may be used. In addition, as the acid end blocking agent (C), the epoxy compound (C-1) and the carbodiimide compound (C-2) may be used in combination, and in that case, the upper limit of each content is the content proportionally divided according to the content ratio of the epoxy compound (C-1) and the carbodiimide compound (C-2). For example, when the epoxy compound (C-1) and the carbodiimide compound (C-2) are used in a mass ratio of 50:50, the upper limit of the epoxy compound (C-1) is 2.5 parts by mass, and the upper limit of the carbodiimide compound (C-2) is 0.75 parts by mass.

[0044] [Amide-based lubricants (D)] The amide-based lubricant (D), one of the components used in the present invention, is an aliphatic compound having an amide group in its chemical structure, and is added to suppress the amount of eye mucus generated during extrusion molding. Specific examples include aliphatic monoamide compounds such as oleyl oleic acid amide, stearyl oleic acid amide, and oleyl stearic acid amide, aliphatic bisamide compounds such as methylene bisstearic acid amide, ethylene bisstearic acid amide, methylene bisoleic acid amide, ethylene bispalmitic acid amide, ethylene bispalmitic acid amide, methylene oleic acid stearic acid diamide, ethylene oleic acid stearic acid diamide, methylene oleic acid palmitic acid diamide, ethylene oleic acid palmitic acid diamide, methylene stearic acid palmitic acid diamide, and ethylene stearic acid palmitic acid diamide, and fatty acid amide-based wax obtained by reacting a mixture of aliphatic monocarboxylic acid and polybasic acid with a diamine. Such a fatty acid amide wax is obtained by a dehydration reaction between a mixture of an aliphatic monocarboxylic acid and a polybasic acid and a diamine. As the aliphatic monocarboxylic acid, saturated aliphatic monocarboxylic acid and hydroxycarboxylic acid are preferable, for example, palmitic acid, stearic acid, behenic acid, montanic acid, 12-hydroxystearic acid, etc. As the polybasic acid, dibasic or higher carboxylic acid, for example, aliphatic dicarboxylic acid such as malonic acid, succinic acid, adipic acid, sebacic acid, pimelic acid, azelaic acid, etc., aromatic dicarboxylic acid such as phthalic acid, terephthalic acid, etc., and alicyclic dicarboxylic acid such as cyclohexane dicarboxylic acid, cyclohexyl succinic acid, etc. As the diamine compound, for example, ethylene diamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylene diamine, meta xylylene diamine, tolylene diamine, para xylylene diamine, phenylene diamine, isophorone diamine, etc. are mentioned. These amide-based lubricants (D) are ideally in a molten state only during extrusion molding, and therefore preferably have a softening temperature within a range of 0 to 30° C. above the melting point of the polyester elastomer (A).If the softening temperature is higher than the processing temperature, the effect of preventing eye discharge during extrusion molding is not sufficiently exhibited, whereas if the softening temperature is too low, bleeding out in the molded product tends to become prominent.

[0045] The amide-based lubricant (D) is an optional component. When contained, the content of the amide-based lubricant (D) is preferably 0.1 to 3 parts by mass, more preferably 0.1 to 2 parts by mass, and even more preferably 0.3 to 1 part by mass, per 100 parts by mass of the polyester elastomer (A).

[0046] [Other additives] The polyester elastomer resin composition of the present invention may contain a general-purpose antioxidant such as an aromatic amine-based, hindered phenol-based, phosphorus-based or sulfur-based antioxidant, if necessary.

[0047] Furthermore, when weather resistance is required for the polyester elastomer resin composition of the present invention, it is preferable to add an ultraviolet absorber and / or a hindered amine compound. For example, benzophenone-based, benzotriazole-based, triazole-based, nickel-based, and salicylic acid-based light stabilizers can be used. Specifically, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, pt-butylphenyl salicylate, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t-amyl-phenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis( α,α-dimethylbenzylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenazotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzothiazole, 2,5-bis-[5'-t-butylbenzoxazolyl-(2)]-thiophene, bis(3,5-di-t-butyl-4-hydroxybenzyl phosphate monoethyl ester)nickel salt, 2-ethoxy-5- Mixture of 85-90% t-butyl-2'-ethyl oxalic acid bis-anilide and 10-15% 2-ethoxy-5-t-butyl-2'-ethyl-4'-t-butyl oxalic acid bis-anilide, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-ethoxy-2'-ethyl oxalic acid bis-anilide, 2-[2'-hydroxy-5'-methyl-3'-(3'',4'',5' Examples of light stabilizers include bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 2-hydroxy-4-i-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, and phenyl salicylate.The content is preferably 0.1% by mass or more and 5% by mass or less based on the mass of the polyester elastomer resin composition.

[0048] The polyester elastomer resin composition of the present invention may contain various other additives. As additives, resins other than polyester elastomers, inorganic fillers, stabilizers, and antiaging agents may be added within a range that does not impair the characteristics of the present invention. In addition, as other additives, color pigments, inorganic and organic fillers, coupling agents, tackiness improvers, quenchers, stabilizers such as metal deactivators, flame retardants, etc. may also be added. In the polyester elastomer resin composition of the present invention, the total of the polyester elastomer (A), the phosphorus-based flame retardant (B), the acid end-capping agent (C), and the amide-based lubricant (D) (the acid end-capping agent (C) and the amide-based lubricant (D) are optional components) preferably accounts for 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0049] [Polyester elastomer resin composition] The acid value of the polyester elastomer resin composition of the present invention is 10 eq / ton or less. The lower limit of the acid value of the polyester elastomer resin composition is not particularly limited, but it is preferably 0 eq / ton. By having the acid value of the polyester elastomer resin composition be 10 eq / ton or less, there are fewer carboxyl terminals that promote hydrolysis of the polyester, and it is preferable that the composition can exhibit better hydrolysis resistance.

[0050] The polyester elastomer resin composition obtained by the present invention has excellent flame retardancy and mechanical properties, and furthermore, can retain the inherent flexibility, moldability, heat resistance, chemical resistance, flex fatigue resistance, abrasion resistance, electrical properties, and other properties of polyester elastomers, and can therefore be used in a wide range of applications, such as various parts of electrical products, hoses, tubes, and cable coating materials. In particular, it is useful to develop it for cable coatings. In addition to these, the polyester elastomer resin composition obtained by the present invention can be shaped into various molded products by injection molding, extrusion molding, transfer molding, blow molding, and the like. EXAMPLES

[0051] 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.

[0052] [Melting point] Using a differential scanning calorimeter "DSC220" manufactured by Seiko Denshi Kogyo Co., Ltd., 5 mg of the measurement sample was placed in an aluminum pan, the lid was pressed down to seal it, and the sample was held at 250°C for 5 minutes to completely melt the sample, then quenched with liquid nitrogen, and then measured at a heating rate of 20°C / min from -150°C to 250°C. The endothermic peak temperature of the obtained thermogram curve was taken as the melting point.

[0053] [Reduced viscosity] 0.05 g of the resin was dissolved in 25 mL of a mixed solvent (phenol / tetrachloroethane=60 / 40 (mass ratio)), and the viscosity was measured at 30° C. using an Ostwald viscometer.

[0054] [Acid value] The acid value (eq / ton) of polyester elastomer (A) was determined by dissolving 200 mg of a thoroughly dried sample (polyester elastomer) in 10 mL of hot benzyl alcohol, cooling the resulting solution, adding 10 mL of chloroform and phenol red, and titrating with a 1 / 25 N potassium alcohol solution (a solution of KOH in methanol). The acid value of the polyester elastomer resin composition was also determined by the same method.

[0055] [Shore D hardness] The hardness was measured using a type D durometer in accordance with JIS K6253:2012. The value was read 15 seconds after the pressure plate was brought into contact with the test piece.

[0056] The components used in the examples are as follows: [Polyester elastomer (A)] (Polyester elastomer A-1) 100 parts by mass of aliphatic polycarbonate diol (carbonate diol UH-CARB200 manufactured by Ube Industries, molecular weight 2000, 1,6-hexanediol type) and 8.6 parts by mass of diphenyl carbonate were charged and reacted at a temperature of 205°C and 130 Pa. After 2 hours, the contents were cooled to obtain aliphatic polycarbonate diol (number average molecular weight 10000). 43 parts by mass of this aliphatic polycarbonate diol (PCD) and 57 parts by mass of polybutylene terephthalate (PBT) having a number average molecular weight of 30000 were stirred at 230°C to 245°C and 130 Pa for 1 hour, and it was confirmed that the resin became transparent, and the contents were taken out and cooled to produce a polyester elastomer. The melting point of this polyester elastomer (A-1) was 207°C, the reduced viscosity was 1.21 dl / g, and the acid value was 44 eq / ton.

[0057] (Polyester elastomer A-2) 100 parts by mass of aliphatic polycarbonate diol (carbonate diol UH-CARB200 manufactured by Ube Industries, molecular weight 2000, 1,6-hexanediol type) and 8.6 parts by mass of diphenyl carbonate were charged and reacted at a temperature of 205°C and 130 Pa. After 1 hour, the contents were cooled to obtain aliphatic polycarbonate diol (number average molecular weight 5000). 43 parts by mass of this aliphatic polycarbonate diol (PCD) and 57 parts by mass of polybutylene terephthalate (PBT) having a number average molecular weight of 30000 were stirred at 230°C to 245°C and 130 Pa for 1 hour, and after confirming that the resin became transparent, the contents were taken out. The pellets taken out were heated at 170 to 180°C and subjected to solid-phase polycondensation to produce a polyester elastomer. This polyester elastomer (A-2) had a melting point of 208° C., a reduced viscosity of 1.21 dl / g, and an acid value of 7 eq / ton.

[0058] (Polyester elastomer A-3) A polyester elastomer was produced using terephthalic acid, 1,4-butanediol, and poly(tetramethylene oxide) glycol (PTMG; number average molecular weight 1000) as the constituent components, with a hard segment (polybutylene terephthalate) / soft segment (PTMG) ratio of 64 / 36 (mass%). The melting point of this polyester elastomer (A-3) was 203°C, the reduced viscosity was 1.75 dl / g, and the acid value was 50 eq / ton.

[0059] (Polyester elastomer A-4) 100 parts by mass of aliphatic polycarbonate diol (carbonate diol UH-CARB200 manufactured by Ube Industries, molecular weight 2000, 1,6-hexanediol type) and 8.6 parts by mass of diphenyl carbonate were charged and reacted at a temperature of 205°C and 130 Pa. After 2 hours, the contents were cooled to obtain aliphatic polycarbonate diol (number average molecular weight 10000). 30 parts by mass of this aliphatic polycarbonate diol (PCD) and 70 parts by mass of polybutylene terephthalate (PBT) having a number average molecular weight of 30000 were stirred at 230°C to 245°C and 130 Pa for 1 hour, and it was confirmed that the resin became transparent, and the contents were taken out and cooled to produce a polyester elastomer. The melting point of this polyester elastomer (A-4) was 212°C, the reduced viscosity was 1.20 dl / g, and the acid value was 41 eq / ton. The physical properties of each polyester elastomer are shown in Table 1.

[0060] [Table 1]

[0061] [Phosphorus-based flame retardants (B)] (B-1) Adeka STAB FP-2200S (a composite flame retardant of melamine pyrophosphate / piperazine pyrophosphate, D50: 10 μm, phosphorus concentration: 19% by mass, manufactured by ADEKA Corporation) (B-2) EXOLIT OP930 (aluminum diethylphosphinate, D50: 4 μm, phosphorus concentration: 23 mass%, manufactured by Clariant Co., Ltd.) (B-3) EXOLIT OP1230 (aluminum diethylphosphinate, D50: 30 μm, phosphorus concentration: 23 mass%, manufactured by Clariant Co., Ltd.) (B-4) BUDIT 3141 (melamine polyphosphate, D50: 8 μm, phosphorus concentration: 10 mass%, manufactured by Budenheim Chemical Factory) The average particle diameter D50 is a value measured by a laser diffraction particle size distribution analyzer, and the phosphorus concentration is a value measured (calculated) by ICP emission spectrometry.

[0062] [Acid end-capping agent (C)] (C-1) Carbodilite HMV-15CA (alicyclic polycarbodiimide, manufactured by Nisshinbo Chemical Inc.) (C-2) Epicron 830 (bisphenol F type diepoxy compound, manufactured by DIC Corporation)

[0063] [Amide-based lubricants (D)] (D-1) Light Amide WH-215 (softening temperature 215°C, manufactured by Kyoeisha Chemical Co., Ltd.)

[0064] Examples 1 to 7, Comparative Examples 1 to 7 100 parts by mass of the polyester elastomer (A) was mixed with the phosphorus-based flame retardant (B), the acid end-capping agent (C) and the amide-based lubricant (D) in the ratios shown in Table 2 and pelletized in a twin-screw extruder. The pellets of this polyester elastomer resin composition were used to carry out the following evaluations. The results are shown in Table 2.

[0065] [Tensile strength and elongation at break] The tensile strength and elongation at break of the composition were measured in accordance with JIS K6251: 2010. Test pieces were prepared by injection molding the resin composition dried under reduced pressure at 100°C for 8 hours into a 100 mm x 100 mm x 2 mm flat plate using an injection molding machine (Yamashiro Seiki Co., Ltd., model-SAV) at a cylinder temperature (Tm+20°C) and a mold temperature of 30°C, and then punching out a dumbbell-shaped No. 3 test piece from the flat plate.

[0066] [Heat and water resistance treatment: Heat and water resistance elongation half-life] The dumbbell-shaped No. 3 test pieces were left for a specified time in air environments at 140°C and 170°C, and in a boiling water environment at 100°C, then removed and the tensile elongation at break was measured in accordance with JIS K6251:2010 as above. The tensile elongation retention at break was calculated using the following formula, and the time at which this value reached 50% (tensile elongation half-life) was used as an index of heat resistance and water resistance. The initial tensile elongation at break is the tensile elongation at break before heat and water resistance treatment. Tensile breaking elongation retention rate (%) = Tensile breaking elongation after each treatment / Initial tensile breaking elongation × 100

[0067] [Extrusion molded product appearance] The pellets melt-kneaded in the twin-screw extruder were extruded again from a T-die in a single-screw extruder to produce a sheet molded product with a thickness of 0.2 mm. The appearance of the extrusion molded product was evaluated based on the appearance of the sheet according to the following criteria. ◯: No roughness or bubbles are observed, and the sheet appearance and surface smoothness are good. ⊚: The sheet appearance and surface smoothness are good as with ◯, and the amount of die deposits is significantly small. ×: The flame retardant caused unevenness and foaming in the sheet, and the sheet appearance was poor.

[0068] [Limiting Oxygen Index] The limiting oxygen index was measured in accordance with JIS K7201-2. The limiting oxygen index is the maximum oxygen concentration that satisfies the measurement criteria for the oxygen index, which are a burning time of 180 seconds or less and a burning distance of 50 mm or less.

[0069] [Table 2]

[0070] As is clear from the results in Table 2, the polyester elastomer resin compositions of the present invention, which are obtained by blending a phosphorus-based flame retardant, an acid end-capping agent, and an amide-based lubricant with a polyester elastomer as shown in Examples 1 to 7, have excellent mechanical properties, heat aging resistance, and water resistance, and also have a high flame retardancy with a limiting oxygen index of 26% or more. In addition, the results are good in all Examples with respect to the appearance of the extrusion molded products, and in particular, a comparison between Example 2 and the other Examples shows that the addition of the amide-based lubricant (D) component further improves the extrusion moldability. A comparison between Examples 1 to 5 and Examples 6 to 7 shows that, compared to Examples 6 to 7 in which the soft segment is PTMG, Examples 1 to 5 in which the soft segment is made of polycarbonate diol tend to exhibit higher flame retardancy, heat resistance, and water resistance. On the other hand, the compositions of Comparative Examples 1 to 7, which do not satisfy the conditions of the present invention, are inferior in any one of tensile elongation at break, appearance of the extrusion molded product, flame retardancy, heat resistance, and water resistance, compared to the compositions of the present invention.

[0071] In Comparative Example 1, in which a polyester elastomer with high surface hardness is used, the mechanical properties are significantly decreased by the heat- and water-resistant treatment, and as a result, the heat resistance and water resistance are poor. In Comparative Example 2, in which no phosphorus-based flame retardant is added, the limit oxygen index LOI is naturally less than 26%, and the flame retardancy is poor. In contrast to Comparative Example 2, in Comparative Example 3, in which an excessive amount of phosphorus-based flame retardant is added, the limit oxygen index LOI is high, but the tensile breaking elongation (mechanical properties) and the appearance of the extrusion molded product are poor. Since the tensile breaking elongation is insufficient at the initial stage, the evaluation of heat resistance and water resistance based on the elongation half-life is considered inappropriate, and no measurement is performed. In Comparative Example 4, in which a phosphorus-based flame retardant with a large particle size D50 is used, the mechanical properties, flame retardancy, heat resistance, and water resistance are excellent, but the extrusion molded product has significant unevenness and is poor in extrusion moldability. Comparative Example 5, in which the amount of the acid end-capping agent, the carbodiimide compound, is excessive, also has excellent mechanical properties, flame retardancy, heat resistance, and water resistance, but foaming behavior is observed in the extrusion molded product, resulting in poor extrusion moldability. In contrast to Comparative Example 5, Comparative Example 6, in which the amount of the acid end-capping agent is small and the terminal acid value is high, has poor water resistance. Comparative Example 7, in which a phosphorus-based flame retardant with a low phosphorus concentration is used, has poor flame retardancy. [Industrial Applicability]

[0072] Thus, the flame-retardant polyester elastomer resin composition of the present invention can provide a flame-retardant polyester elastomer composition that has excellent extrusion moldability and surface smoothness even in a thin-walled shape while maintaining mechanical properties, and is halogen-free and has excellent flame retardancy, heat aging resistance, and hydrolysis resistance. Therefore, it can be used in a wide range of applications, such as various parts of electrical products, hoses, tubes, and cable covering materials. In addition, the resin composition obtained by the present invention can be molded into various molded products by injection molding, extrusion molding, transfer molding, blow molding, etc.

Claims

1. A polyester elastomer resin composition containing a polyester elastomer (A) and a phosphorus-based flame retardant (B), The polyester elastomer (A) is composed of a hard segment made of a polyester having an aromatic dicarboxylic acid and an aliphatic or alicyclic diol as constituent components, and at least one soft segment selected from an aliphatic polyether, an aliphatic polyester, and an aliphatic polycarbonate, and has a surface hardness of Shore D55 or less; The phosphorus-based flame retardant (B) has an average particle size D50 of 20 μm or less and a phosphorus concentration of 15 mass% or more, The polyester elastomer resin composition has an acid value of 10 eq / ton or less, and contains, relative to 100 parts by mass of the polyester elastomer (A), 5 to 50 parts by mass of the phosphorus-based flame retardant (B), and further contains, as an acid end-blocking agent (C), 0 to 5 parts by mass of an epoxy compound (C-1) or 0 to 1.5 parts by mass of a carbodiimide compound (C-2).

2. The polyester elastomer resin composition according to claim 1, wherein the hard segment of the polyester elastomer (A) is a polyester having terephthalic acid and 1,4-butanediol as constituent components, the soft segment is an aliphatic polycarbonate diol, and the melting point of the polyester elastomer (A) is 150 to 230°C.

3. 3. The polyester elastomer resin composition according to claim 1, wherein the phosphorus-based flame retardant (B) is a metal phosphinate, a (poly)phosphate, or both.

4. The polyester elastomer resin composition according to any one of claims 1 to 3, further comprising 0.1 to 3 parts by mass of an amide-based lubricant (D) per 100 parts by mass of the polyester elastomer (A).

5. The polyester elastomer resin composition according to any one of claims 1 to 4, which is used for cable coating.

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