JP2015183163A - polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin composition excellent in heat resistance and chemical resistance.SOLUTION: Provided is a polyester resin composition satisfying the following requirements (1) to (4): (1) that the polyester resin composition contains a phosphorous element, and, provided that the phosphorous element contained in te polyester resin composition is defined as P(mol/t), the following formula (i) is satisfied: 2.5≤P≤17.5; (2) that the polyester resin composition contains a sulfur element, and provided that the sulfur element contained in the polyester resin composition is defined as S(mol/t), the following formula (ii) is satisfied: (ii) 4.0≤P+S≤28.5; (3) that the polyester resin composition includes bivalent metals, and the total of the bivalent metal elements in the polyester resin composition is defied as M(mol/t), the following formula (iii) is satisfied: 0.03≤M/(P+S)≤1.30; and (4) that the weight loss in a chemical resisting test is 1.0 wt.% or lower.

Description

  The present invention relates to a polyester resin composition excellent in heat resistance and chemical resistance.

  Polyester is excellent in mechanical properties, thermal properties, chemical resistance, electrical properties, and moldability, and is used in various applications.

  The polyester film made from the polyester is used for solar cell back sheets, water heater motors, car air conditioner motors and drive motors used in hybrid vehicles because of its mechanical and electrical characteristics. It is used as various industrial materials such as electrical insulating materials, magnetic recording materials, capacitor materials, packaging materials, building materials, photographic applications, graphic applications, and thermal transfer applications.

  Among these applications, electrical insulating materials are often used in harsh environments for a long period of time. Polyesters are mechanically brittle due to a decrease in molecular weight and an increase in crystallinity due to oxidative degradation and hydrolysis. Since physical properties and the like deteriorate, when used in a harsh environment for a long period of time, improvement in heat resistance and moist heat resistance is required.

  In particular, among electrical insulating materials, an insulating film for an air conditioner is indispensable for heat resistance and chemical resistance because it is used in an environment exposed to high-temperature and high-pressure refrigerant gas and oil for a long time. Furthermore, it has been regarded as a problem that HCFC (hydrochlorofluorocarbon), which has been used as a refrigerant, has a high global warming potential, and switching to HFC (hydrofluorocarbon), which has a lower global warming potential than HCFC, is progressing. Refrigerant R32 represented by HFC has been pointed out that the operating environment temperature of the compressor is higher than before due to its thermal characteristics, and the heat resistance and chemical resistance to the film used for the compressor motor application of the air conditioner. The demand for sex is increasing.

  As a polyester resin composition used for electrical material applications and solar cell applications, a polyester resin composition is disclosed in which the heat resistance is improved by setting the ratio of the phosphorus compound and the metal compound within a specific range (Patent Document 1). 2).

  In addition, as a means for improving the heat resistance of the polyester resin composition, a phosphorus compound, a phenolic antioxidant, or a sulfurous antioxidant is added during polymerization of the polyester, resulting in the catalyst used during the polymerization. The polyester resin composition which suppresses a thermal decomposition reaction is disclosed (patent documents 3 to 6).

International Publication No. 2010/103945 Pamphlet JP2013-129820A JP 2009-67944 A JP 2011-12200 A Japanese Patent Laid-Open No. 11-60971 JP 2012-41520 A

  However, although the polyester resin composition obtained by the methods described in Patent Documents 1 and 2 has a certain heat resistance improvement effect, it has a problem that the heat resistance is low because the effect of suppressing oxidative degradation is not sufficient. Become.

  Patent Documents 3, 4, 5, and 6 are examples in which the polyester resin composition is in contact with an organic solvent when the ratio of the phosphorus compound, the phenolic antioxidant, and the sulfurous antioxidant is large with respect to the polymerization reaction catalyst. When used, the phosphorus compound, the phenolic antioxidant, and the sulfurous antioxidant are eluted into the organic solvent, resulting in a problem that the chemical resistance is low. Moreover, as a result of the phosphorus compound, the phenolic antioxidant and the sulfurous antioxidant being eluted into the organic solvent, there is a problem that the heat resistance is deteriorated.

  Then, in view of said subject, the objective of this invention is providing the polyester resin composition excellent in heat resistance and chemical resistance.

In order to solve the above problems, the present invention has the following configuration. That is,
[I] A polyester resin composition that satisfies the following requirements (1) to (4).
(1) When the polyester resin composition contains phosphorus element and the phosphorus element contained in the polyester resin composition is P (mol / t), the following formula (i) is satisfied.

(I) 2.5 ≦ P ≦ 17.5
(2) The polyester resin composition further contains a sulfur element, and when the sulfur element contained in the polyester resin composition is S (mol / t), the following formula (ii) is satisfied.

(Ii) 4.0 ≦ P + S ≦ 28.5
(3) The polyester resin composition contains a divalent metal, and satisfies the following formula (iii) when the amount of the divalent metal element in the polyester resin composition is M (mol / t).

(Iii) 0.03 ≦ M / (P + S) ≦ 1.30
(4) The weight reduction rate in the chemical resistance test is 1.0% by weight or less.
[II] The polyester resin composition according to [I], which satisfies the following requirements (5) to (6):
(5) The polyester resin composition is a polyester resin composition obtained by adding a phosphorus-based antioxidant and a sulfur-based antioxidant.
(6) The divalent metal element contained in the polyester resin composition is at least one selected from Ca element and Mn element.
[III] The polyester resin composition according to [II], wherein the phosphorus antioxidant is a phosphite antioxidant.
[IV] The polyester resin composition is a polyester resin composition obtained by adding a phenolic antioxidant, and when the addition amount of the phenolic antioxidant is PH (mol / t), the following (iv The polyester resin composition according to any one of [I] to [III], which satisfies the formula:

(Iv) 1.8 ≦ PH ≦ 9.0
[V] The polyester resin composition according to [IV], wherein the phenolic antioxidant is a hindered phenolic antioxidant.
[VI] The polyester resin composition according to [IV] or [V], which satisfies the following formula (v):

(V) 0.02 ≦ M / (P + S + PH) ≦ 0.87
[VII] The polyester resin composition according to any one of [I] to [VI], wherein the intrinsic viscosity is in the range of 0.6 dl / g to 1.0 dl / g.
[VIII] The polyester resin composition according to any one of [I] to [VII], wherein the carboxyl group terminal amount is 20 eq / ton or less.
[IX] The polyester resin composition according to any one of [I] to [VIII], wherein a thermal decomposition weight reduction rate at 300 ° C. in thermogravimetry is 0.5% by weight or less.
[X] A biaxially oriented polyester film using the polyester resin composition according to any one of [I] to [IX].
[XI] The biaxially oriented polyester film according to [X], wherein the time required for the strength retention to be 50% or less in a 180 ° C. dry heat test is 450 hours or more.
[XII] The biaxially oriented polyester film according to [X] or [XI], which is used for electrical insulation.

  According to the present invention, a polyester resin composition having excellent heat resistance and chemical resistance can be provided. Moreover, by using the polyester resin composition of the present invention as a biaxially stretched film, it is suitable for uses such as magnetic materials, solar cells, and packaging, especially for electrical insulation that requires heat resistance and chemical resistance. Can be obtained.

  The polyester used in the present invention is obtained by polycondensation of a dicarboxylic acid component and a diol component. In addition, in this specification, a structural component shows the minimum unit which can be obtained by hydrolyzing polyester.

  Examples of the dicarboxylic acid component constituting the polyester include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, eicosandioic acid, pimelic acid, azelaic acid, methylmalon. Aliphatic dicarboxylic acids such as acid, ethylmalonic acid and the like, adamantane dicarboxylic acid, norbornene dicarboxylic acid, isosorbide, cyclohexanedicarboxylic acid, decalin dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4 -Naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenylether dicarboxylic acid, 5-sodium Sulfoiso Tal acid, phenyl ene boys carboxylic acid, anthracene dicarboxylic acid, phenanthrene carboxylic acid, 9,9'-bis (4-carboxyphenyl) dicarboxylic acids such as fluorene acids and aromatic dicarboxylic acids, or include an ester derivative thereof.

  Examples of the diol component constituting the polyester include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, and 1,3-butanediol. Aliphatic diols such as cyclohexanedimethanol, spiroglycol and isosorbide, bisphenol A, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 9,9′-bis (4 Examples include -hydroxyphenyl) fluorene, diols such as aromatic diols, and a series of a plurality of the above diols.

  The polyester of the present invention may be copolymerized with a monofunctional compound such as lauryl alcohol or phenyl isocyanate, or trimellitic acid, pyromellitic acid, glycerol, pentaerythritol and 2,4-dioxybenzoic acid. Trifunctional compounds and the like may be copolymerized within a range in which the polymer is substantially linear without excessive branching or crosslinking. Furthermore, in addition to the acid component and the diol component, aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid, m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, and p-aminophenol and p-aminobenzoic acid, The copolymer can be further copolymerized as long as the effect of the present invention is not impaired. As the polyester, polyethylene terephthalate and polyethylene naphthalate are preferably used. The polyester may be a copolymer or a modified product thereof. From the viewpoint of crystallinity, polyethylene terephthalate and polyethylene naphthalate are preferably the main components, and particularly preferably 90% or more is polyethylene terephthalate and polyethylene naphthalate.

  In the polyester resin composition of the present invention, containing a phosphorus element is important from the viewpoint of heat resistance, and when the phosphorus element contained in the polyester resin composition is P (mol / t), the following (i) It is necessary to satisfy the formula.

(I) 2.5 ≦ P ≦ 17.5
P is more preferably 3.3 mol / t or more and 14.0 mol / t or less. More preferably, they are 3.3 mol / t or more and 12.3 mol / t or less.

  The polycondensation catalyst present in the polyester resin composition is active in thermal decomposition reactions and oxidative decomposition reactions, but the phosphorus element must be present in the polyester resin composition within the range satisfying the above formula (i). Thus, the activity of the polycondensation catalyst can be extremely suppressed. As a result, it is possible to obtain a polyester resin composition excellent in heat resistance in which the increase amount of carboxyl end groups and the decrease amount of intrinsic viscosity of the polyester resin are remarkably small even under high temperature conditions.

  On the other hand, if the content of the phosphorus element is less than 2.5 mol / t, a reverse reaction of the remaining polymerization reaction catalyst occurs and heat resistance is reduced or foreign matter is generated. On the other hand, if it exceeds 17.5 mol / t, the polycondensation reaction is deactivated, the polymerization reaction is delayed, the reaction does not proceed to the target degree of polymerization, or foreign matters derived from phosphorus compounds are generated. Occur.

  In addition, it is preferable that the polyester resin composition containing the phosphorus element of the present invention is obtained by adding a phosphorus compound at any point of time when the polyester resin composition is synthesized. Moreover, it is preferable that a phosphorus compound is a phosphorus antioxidant. In addition, the antioxidant as used in the field of this invention refers to the compound which has the effect which suppresses the oxidative decomposition reaction of polyester by having radical scavenging ability and peroxide resolution | decomposability. Examples of the phosphorus compound include phosphite compounds, phosphate compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphonous acid compounds, phosphinic acid compounds, and phosphine compounds.

  Specific examples of the phosphite compound include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4 -Di-t-butylphenyl) phosphite, tris (2-t-butyl-4-methylphenyl) phosphite, tris (cyclohexylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butyl) Phenyl) octyl phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10-dihydro -9-oxa-10-phosphaphenanthrene-10-oxide, 0-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl phosphite), 4, 4'-isopropylidene-bis (phenyl-di-alkyl (C12-C15) phosphite), 4,4'-isopropylidene-bis (diphenylmonoalkyl (C12-C15) phosphite), 1,1,3- Tris (2-methyl-4-di-tridecyl phosphite-5-t-butylphenyl) butane, tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene diphosphite, cyclic Neopentanetetrayl bis (octadecyl phosphite), cyclic neopentane tetrayl bis (isodecyl phosphite) Cyclic neopentanetetrayl bis (nonylphenyl phosphite), cyclic neopentanetetrayl bis (2,4-di-t-butylphenyl phosphite), cyclic neopentanetetrayl bis (2,4-dimethylphenyl) Phosphite), cyclic neopentanetetraylbis (2,6-di-t-butylphenylphosphite), 2,2′-bis (2,6-di-t-butyl-4-methylphenoxy) -5 , 5'-spirobi [1,3,2-dioxaphosphorinane].

  Phosphate compounds include phosphoric acid, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate , Tripotassium phosphate, lithium dihydrogen phosphate, dilithium hydrogen phosphate, and trilithium phosphate.

  Phosphonic acid compounds include methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, isopropylphosphonic acid, butylphosphonic acid, phenylphosphonic acid, benzylphosphonic acid, tolylphosphonic acid, xylylphosphonic acid, biphenylphosphonic acid, naphthylphosphonic acid Anthrylphosphonic acid, 2-carboxyphenylphosphonic acid, 3-carboxyphenylphosphonic acid, 4-carboxyphenylphosphonic acid, 2,3-dicarboxyphenylphosphonic acid, 2,4-dicarboxyphenylphosphonic acid, 2,5 -Dicarboxyphenylphosphonic acid, 2,6-dicarboxyphenylphosphonic acid, 3,4-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid, 2,3,4-tricarboxyphenylphosphonic acid, 2 , 3, 5 Tricarboxyphenylphosphonic acid, 2,3,6-tricarboxyphenylphosphonic acid, 2,4,5-tricarboxyphenylphosphonic acid, 2,4,6-tricarboxyphenylphosphonic acid, methylphosphonic acid dimethyl ester, methylphosphonic acid diethyl Ester, ethylphosphonic acid dimethyl ester, ethylphosphonic acid diethyl ester, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, phenylphosphonic acid diphenyl ester, benzylphosphonic acid dimethyl ester, benzylphosphonic acid diethyl ester, benzylphosphonic acid diphenyl ester, Lithium (ethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate), sodium (3,5-di-tert-butyl-4-hydroxy) Ethyl benzylphosphonate), magnesium bis (3,5-di-tert-butyl-4-hydroxybenzylphosphonate), calcium bis (3,5-di-tert-butyl-4-hydroxybenzylphosphonate), Examples include diethylphosphonoacetic acid, methyl diethylphosphonoacetate, and ethyl diethylphosphonoacetate.

  Phosphinic acid compounds include hypophosphorous acid, sodium hypophosphite, methylphosphinic acid, ethylphosphinic acid, propylphosphinic acid, isopropylphosphinic acid, butylphosphinic acid, phenylphosphinic acid, tolylphosphinic acid, xylylphosphinic acid , Biphenylylphosphinic acid, diphenylphosphinic acid, dimethylphosphinic acid, diethylphosphinic acid, dipropylphosphinic acid, diisopropylphosphinic acid, dibutylphosphinic acid, ditolylphosphinic acid, dixylphosphinic acid, dibiphenylylphosphinic acid, naphthylphosphinic acid Anthrylphosphinic acid, 2-carboxyphenylphosphinic acid, 3-carboxyphenylphosphinic acid, 4-carboxyphenylphosphinic acid, 2,3-dicarboxyphenylphosphine Acid, 2,4-dicarboxyphenylphosphinic acid, 2,5-dicarboxyphenylphosphinic acid, 2,6-dicarboxyphenylphosphinic acid, 3,4-dicarboxyphenylphosphinic acid, 3,5-dicarboxyphenyl Phosphinic acid, 2,3,4-tricarboxyphenylphosphinic acid, 2,3,5-tricarboxyphenylphosphinic acid, 2,3,6-tricarboxyphenylphosphinic acid, 2,4,5-tricarboxyphenylphosphinic acid 2,4,6-tricarboxyphenylphosphinic acid, bis (2-carboxyphenyl) phosphinic acid, bis (3-carboxyphenyl) phosphinic acid, bis (4-carboxyphenyl) phosphinic acid, bis (2,3-di Carboxyphenyl) phosphinic acid, bis (2,4-dicarboxy) Enyl) phosphinic acid, bis (2,5-dicarboxyphenyl) phosphinic acid, bis (2,6-dicarboxyphenyl) phosphinic acid, bis (3,4-dicarboxyphenyl) phosphinic acid, bis (3,5- Dicarboxyphenyl) phosphinic acid, bis (2,3,4-tricarboxyphenyl) phosphinic acid, bis (2,3,5-tricarboxyphenyl) phosphinic acid, bis (2,3,6-tricarboxyphenyl) phosphine Acid, bis (2,4,5-tricarboxyphenyl) phosphinic acid, and bis (2,4,6-tricarboxyphenyl) phosphinic acid, methylphosphinic acid methyl ester, dimethylphosphinic acid methyl ester, methylphosphinic acid ethyl ester Dimethyl phosphinic acid ethyl ester, ethyl phosphinic acid Chill ester, diethylphosphinic acid methyl ester, ethylphosphinic acid ethyl ester, diethylphosphinic acid ethyl ester, phenylphosphinic acid methyl ester, phenylphosphinic acid ethyl ester, phenylphosphinic acid phenyl ester, diphenylphosphinic acid methyl ester, diphenylphosphinic acid ethyl ester, Examples thereof include diphenylphosphinic acid phenyl ester, benzylphosphinic acid methyl ester, benzylphosphinic acid ethyl ester, benzylphosphinic acid phenyl ester, bisbenzylphosphinic acid methyl ester, bisbenzylphosphinic acid ethyl ester, and bisbenzylphosphinic acid phenyl ester.

  Examples of the phosphine oxide compound include trimethylphosphine oxide, triethylphosphine oxide, tripropylphosphine oxide, triisopropylphosphine oxide, tributylphosphine oxide, triphenylphosphine oxide, and the like.

  Examples of the phosphonous acid compound include methylphosphonous acid, ethylphosphonous acid, propylphosphonous acid, isopropylphosphonous acid, butylphosphonous acid, and phenylphosphonous acid.

  Phosphinic acid compounds include methylphosphinic acid, ethylphosphinic acid, propylphosphinic acid, isopropylphosphinic acid, butylphosphinic acid, phenylphosphinic acid, dimethylphosphinic acid, diethylphosphinic acid, dipropylphosphinic acid. Examples include phosphinic acid, diisopropylphosphinic acid, dibutylphosphinic acid, diphenylphosphinic acid, and the like.

  Examples of the phosphine compound include methylphosphine, dimethylphosphine, trimethylphosphine, melephosphine, diethylphosphine, triethylphosphine, phenylphosphine, diphenylphosphine, and triphenylphosphine.

  The phosphorus compound is preferably any one or two of these. A phosphorus antioxidant is preferable, and a phosphite antioxidant is more preferable.

  As a method of adding phosphorus element to the polyester resin composition of the present invention, the pressure in the reactor is reduced and the polycondensation reaction is started until the polymerization is substantially completed, or the polyester resin composition is melt-kneaded. The method of doing is mentioned. Preferably, it is a method of adding at the time of polyester polymerization from the viewpoint of suppressing thermal deterioration. Further, when the intrinsic viscosity of the polyester resin composition is 40 to 99% of the intended intrinsic viscosity, it is preferable because side reactions can be suppressed with very little deactivation of the polycondensation catalyst. Preferably it is between 50 and 98%, and particularly preferably between 75 and 98%. The intrinsic viscosity of the polyester at the time when the phosphorus element is added may be calculated by directly sampling and measuring the viscosity by the method described later, or may be calculated from the torque load applied to the stirring blade of the reactor. The phosphorus element of the present invention may be added in several portions, or may be continuously added with a feeder or the like. When adding phosphorus element, phosphorus element may be added alone, dissolved or dispersed in a diol component such as ethylene glycol, or a master pellet containing phosphorus element at a high concentration May be added. However, if a diol component such as ethylene glycol is brought in and added in a large amount, depolymerization (polyester main chain cleavage reaction) of the polyester resin composition proceeds. Therefore, it is preferable to add a phosphorus element alone. .

Moreover, it is important that the polyester resin composition of the present invention contains a sulfur element together with a phosphorus element. It is important from the viewpoint of heat resistance that the phosphorus element and sulfur element of the polyester resin composition are in a specific range. When the sulfur element contained in the polyester resin composition is S (mol / t), the following ( ii) It is necessary to satisfy the equation.
(Ii) 4.0 ≦ P + S ≦ 28.5
P + S is more preferably 6.7 mol / t or more and 21.0 mol / t or less. More preferably, it is 6.7 mol / t or more and 17.5 mol / t or less. The presence of the sulfur element in the polyester resin composition improves the heat resistance and the strength elongation retention in the tensile test. Furthermore, the presence of the phosphorus element and the sulfur element in the polyester resin composition within the range satisfying the above formula (ii) has the effect of adding the heat resistance improvement effect by the phosphorus element and the heat resistance improvement effect by the sulfur element. A polyester resin composition having a superior synergistic effect and excellent heat resistance can be obtained.

  When P + S is less than 4.0 mol / t, a reverse reaction of the remaining polymerization reaction catalyst occurs and the heat resistance is lowered. When P + S exceeds 28.5 mol / t, the polycondensation reaction is deactivated and the polymerization reaction is caused. Problems such as delay, reaction does not proceed to the target degree of polymerization, and foreign substances derived from phosphorus compounds and sulfur compounds occur.

  In addition, it is preferable that the polyester resin composition containing the sulfur element of the present invention is obtained by adding a sulfur compound at any time when the polyester resin composition is synthesized. The sulfur compound is preferably a sulfur-based antioxidant. Specific examples of the sulfur antioxidant include dilauryl 3,3′-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3′-thiodipropionate, lauryl stearyl 3 , 3′-thiodipropionate, pentaerythritol-tetrakis- (β-lauryl-thio-propionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5 , 5] Undecane. Of these, pentaerythritol-tetrakis- (β-lauryl-thio-propionate) is particularly preferable.

  As a method for adding the sulfur element to the polyester resin composition of the present invention, the pressure in the reactor is reduced and the polycondensation reaction is started until the polymerization is substantially completed, or the polyester resin composition is melt-kneaded. The method of doing is mentioned. Preferably, it is a method of adding at the time of polyester polymerization from the viewpoint of suppressing thermal deterioration. Further, when the intrinsic viscosity of the polyester resin composition is 40 to 99% of the intended intrinsic viscosity, it is preferable because side reactions can be suppressed with very little deactivation of the polycondensation catalyst. Preferably it is between 50 and 98%, and particularly preferably between 75 and 98%. The intrinsic viscosity of the polyester at the time of adding sulfur may be calculated by directly sampling and measuring the viscosity by the method described later, or may be calculated from the torque load applied to the stirring blade of the reactor. The sulfur element of the present invention may be added in several divided portions, or may be continuously added with a feeder or the like. When adding a sulfur element, the sulfur element may be added alone, or may be added in a state dissolved or dispersed in a diol component such as ethylene glycol, or a master pellet containing a high concentration of sulfur element. May be added. However, if a diol component such as ethylene glycol is brought in and added in a large amount, depolymerization (polyester main chain cleavage reaction) of the polyester resin composition proceeds, so it is preferable to add a sulfur element alone. . Moreover, the method of melt-kneading with a polyester resin composition is mentioned. Preferably, it is a method of adding at the time of polyester polymerization from the viewpoint of suppressing thermal deterioration.

  The polyester resin composition of the present invention needs to contain a divalent metal element from the viewpoint of suppressing the elution of phosphorus element and sulfur element and improving chemical resistance. Examples of the divalent metal element include Mg element, Ca element, Mn element, Co element, Sr element, Ba element, Zn element, Zr element, Ti element and the like, and it is necessary to include one or more of these divalent metal elements. There is.

Further, when the sum of divalent metal elements contained in the polyester resin composition is M (mol / t), the following formula (iii) must be satisfied in order to improve heat resistance and chemical resistance.
(Iii) 0.03 ≦ M / (P + S) ≦ 1.30
M / (P + S) is more preferably 0.04 or more and 0.57 or less. More preferably, it is 0.05 or more and 0.37 or less.

  The presence of the divalent metal element in the polyester resin composition improves the heat and moisture resistance and imparts electrostatic application characteristics during film formation. Furthermore, by including a phosphorus element, a sulfur element, and a divalent metal element in the polyester resin composition within a range satisfying the above (iii), an anion of the phosphorus element and the sulfur element and a cation of the divalent metal element can be obtained. Attracting by electrical interaction, phosphorus element and sulfur element can suppress elution from the polyester resin composition, and chemical resistance is improved. In addition, when the divalent metal element, the phosphorus element, and the sulfur element interact electrically, a reverse reaction caused by the catalytic action of the divalent metal element is suppressed, and heat resistance is improved.

  When M / (P + S) is less than 0.03, the chemical resistance is lowered, and when it exceeds 1.30, the reverse reaction of the transesterification reaction cannot be suppressed and the heat resistance is lowered or foreign matter is likely to be generated. Become.

  The divalent metal element is preferably at least one selected from Ca element and Mn element from the viewpoint of affinity with phosphorus element and sulfur element.

  The polyester resin composition of the present invention needs to have a weight reduction rate of 1.0% by weight or less in a chemical resistance test. The chemical resistance test in the present invention refers to an immersion treatment with xylene, and the weight reduction rate in the chemical resistance test is determined as follows.

(Weight reduction rate in chemical resistance test)
The polyester resin composition is formed into a film having a thickness of 1.0 mm and cut out to have a size of 10 cm × 10 cm. The number of samples is n = 3.

And based on JIS-K7114 (2001),
Measure the weight of the cut sample before the chemical resistance test. An average value of the weights of the samples is obtained, and the weight of the average value is M0.

  Next, the film sample is immersed in 500 mL of xylene and treated for 16 hours in a nitrogen atmosphere at a temperature of 140 ° C.

After completion of the immersion treatment, the film is dried in a vacuum dryer at a temperature of 180 ° C. for 4 hours, and then the weight of the film sample is measured. An average value of the weights of the film samples is obtained, and the average value is defined as a weight M1 after the chemical resistance test.
Using the obtained weight M0 before the chemical resistance test and weight M1 after the chemical resistance test, the weight reduction rate is calculated by the following equation (a).
(A) Weight reduction rate (%) = (M0−M1) / M1 × 100
The weight reduction rate is more preferably 0.7% by weight or less, and further preferably 0.5% by weight or less.

  When the weight reduction rate exceeds 1.0% by weight, when the polyester resin composition is used in a form in contact with the organic solvent, the phosphorus compound and the sulfur-based antioxidant are eluted into the organic solvent. As a result, the decrease in intrinsic viscosity under high temperature conditions and the increase in the amount of terminal carboxyl groups become remarkable, and the heat resistance deteriorates. In addition, when the polyester resin composition of the present invention is used for electrical insulation applications such as for air conditioner compressor motors, phosphorus compounds and sulfur-based antioxidants are eluted in the refrigerant, which is an organic solvent, to reduce the refrigerant function. This is not preferable.

  The polyester resin composition of the present invention preferably has a haze change amount of 10% or less in a chemical resistance test from the viewpoint of chemical resistance. The chemical resistance test in the present invention refers to an immersion treatment with xylene, and the amount of change in haze in the chemical resistance test is determined as follows.

(Haze change in chemical resistance test)
The polyester resin composition is formed into a film having a thickness of 1.0 mm and cut out to have a size of 10 cm × 10 cm. The number of samples is n = 3. And based on JIS-K7105 (1981), it measures using fully automatic direct reading haze computer HGM-2DP (made by Suga Test Instruments Co., Ltd.). This is repeated 10 points at random. The average value of the haze values of the samples is obtained, and the haze value of the average value is defined as H0. Next, based on JIS-K7114 (2001), the said film sample is immersed in 500 mL of xylene, and it processes for 16 hours by temperature 140 degreeC and nitrogen atmosphere.

After the immersion treatment, the haze value after the immersion is measured. This is repeated 10 points at random. The average value of the haze values of the samples is obtained, and the haze value of the average value is defined as H1.
Using the obtained haze value H0 before immersion and haze value H1 after immersion, the haze value change amount ΔH is calculated by the following equation (b).

(B) ΔH (%) = H1−H0
The amount of change in haze is more preferably 5% or less, and still more preferably 2% or less. When the amount of change in haze exceeds 10%, the phosphorus compound and the sulfur-based antioxidant become foreign matters and precipitate as oligomers, resulting in a decrease in chemical resistance.

The polyester resin composition of the present invention is a polyester resin composition obtained by adding a phenolic antioxidant, and the amount of the phenolic antioxidant added to the polyester resin composition is PH (mol). / T), the following formula (iv) is preferably satisfied.
(Iv) 1.8 ≦ PH ≦ 9.0
More preferably, it is 2.8 mol / t or more and 8.5 mol / t or less. More preferably, they are 3.8 mol / t or more and 5.0 mol / t or less.

  By adding a phenolic antioxidant to the polyester resin composition, oxidative degradation of the polyester resin composition is suppressed and heat resistance is improved.

  As the phenolic antioxidant used in the present invention, conventionally known ones can be used. Preferably, the hindered phenolic antioxidant, which is a hindered phenolic antioxidant, is, for example, triethylene glycol- Bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, pentaerythrityl tetrakis [3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl) 4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,5-di-t-butyl) -4-hydroxy-hydrocinnamamide), 3,5-di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris (3,3 5-di-t-butyl-4-hydroxybenzyl) benzene, bis (3,5-di-t-butyl-4-hydroxybenzylphosphonate ethyl) calcium, tris- (3,5-di-t-butyl- 4-hydroxybenzyl) -isocyanurate, isooctyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,9-bis [2- { - (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-spiro [5.5], and undecane. More preferably, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 3,9-bis [2- {3- (3 -t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane.

  If the amount of the phenolic antioxidant added is 1.8 mol / t or less, the heat resistance may be insufficiently improved, and if it exceeds 9.0 mol / t, bleeding out occurs and the moldability is reduced. May decrease.

  Examples of the method for adding the phenolic antioxidant include polyester polymerization and melt kneading with a polyester resin composition. Preferably, it is a method of adding at the time of polyester polymerization from the viewpoint of suppressing thermal deterioration.

Further, the polyester resin composition of the present invention preferably satisfies the following formula (v) from the viewpoint of further improving heat resistance and chemical resistance: (v) 0.02 ≦ M / (P + S + PH) ≦ 0.87
The polyester resin composition of the present invention contains phosphorus element, sulfur element and divalent metal element in a range satisfying (i) to (iii), and then a phenolic antioxidant in a range satisfying (v). By adding it, the heat resistance can be drastically improved by the synergistic effect of phosphorus element, sulfur element and phenolic antioxidant, and the phosphorus element and sulfur from the polyester resin composition by interaction with the divalent metal. Elution of elements and phenolic antioxidants can be suppressed.

  M / (P + S + PH) is more preferably 0.03 or more and 0.4 or less, and further preferably 0.04 or more and 0.23 or less. If M / (P + S + PH) is less than 0.02, the chemical resistance improvement effect may not be sufficiently exhibited. If it exceeds 0.87, the effect of improving heat resistance may not be sufficiently obtained. Foreign matter may be easily generated.

  The polyester resin composition of the present invention preferably has an intrinsic viscosity of 0.6 dl / g or more and 1.0 dl / g or less from the viewpoint of mechanical properties. Furthermore, it is preferably from 0.7 dl / g to 0.9 dl / g from the viewpoint of heat resistance.

  The polyester resin composition of the present invention has a terminal carboxyl group amount of 20 eq. / Ton or less is preferable from the viewpoint of heat resistance. More preferably, 15 eq. / Ton or less.

  From the viewpoint of heat resistance, the polyester resin composition of the present invention preferably has a thermal decomposition reduction amount at 300 ° C. of 0.5% by weight or less in thermogravimetry. More preferably, it is 0.4 weight%, More preferably, it is 0.3 weight% or less. If the thermal decomposition reduction amount is 0.5% by weight or more, bleed out may occur during extrusion and the moldability may deteriorate.

  The amount of thermal decomposition reduction can be reduced by increasing the content of phosphorus element and sulfur element in the polyester resin composition or increasing the amount of phenolic antioxidant added, but it is contained in the polyester resin composition. If the divalent metal element is excessively present, the thermal decomposition reduction tends to increase. In addition, even when the amount of the divalent metal element contained in the polyester resin composition is excessive with respect to the phosphorus element or sulfur element, the divalent metal element formed as a foreign substance is precipitated as an oligomer, thereby causing thermal decomposition. Decrease increases. Therefore, the amount of phosphorus element, sulfur element and divalent metal element contained in the polyester composition, and the addition amount of the phenolic antioxidant are within the above-mentioned preferable ranges, thereby reducing the thermal decomposition reduction. be able to.

  The polyester resin composition of the present invention may contain a metal element other than a divalent metal element. For example, Sb element which has polycondensation reaction catalytic ability, Ge element, and Na element and K element which are alkali metal elements are mentioned.

  On the other hand, if the metal element is excessively present in the polyester resin composition, the crystallization speed of the polyester resin composition is increased, and the heat resistance and chemical resistance may be lowered. That is, the content of the metal element other than the divalent metal element and the divalent metal element is preferably as small as possible, specifically 1000 ppm or less. More preferably, the content of divalent metal elements and metal elements other than divalent metals is preferably 500 ppm or less. The content of a divalent metal element or a metal element other than a divalent metal here refers to a metal element that is soluble in a polyester composition, and is insoluble in a polyester composition such as titanium oxide or barium sulfate. The content derived from the metal compound is not included.

  Below, the manufacturing method of the polyester resin composition of this invention is demonstrated. Although the example of a polyethylene terephthalate is described as a specific example, it is not limited to this.

  The polyester resin composition of the present invention is a polyester resin composition comprising an aromatic dicarboxylic acid or an ester-forming derivative of an aromatic dicarboxylic acid and a linear alkylene glycol having 2 to 4 carbon atoms. It can be obtained through a step of obtaining a coalescence (first step) and a step of raising the degree of polymerization (second step) by subjecting the polyester low polymer obtained in the first step to a polymerization reaction. You may add the 3rd process which performs solid-phase polymerization reaction as needed.

  In the first step, for example, terephthalic acid or dimethyl terephthalate and ethylene glycol can be used for esterification or transesterification by a known method. For example, when performing the transesterification reaction, a transesterification catalyst such as magnesium acetate, calcium acetate, manganese acetate, and cobalt acetate can be used, and antimony trioxide as a polymerization catalyst may be added. By adding several ppm of an alkali metal such as potassium hydroxide during the esterification reaction, diethylene glycol by-product is suppressed.

In the second step, after the esterification reaction or transesterification reaction is substantially completed,
This is a step of starting the polymerization reaction by reducing the pressure in the reactor and then adding the polycondensation catalyst to substantially complete the polymerization.

  As the polymerization catalyst, an ethylene glycol solution of germanium dioxide, antimony trioxide, titanium alkoxide, a titanium chelate compound, or the like can be used.

  The phosphorus element, the sulfur element, the divalent metal element, and the phenolic antioxidant may be contained in any of the steps for producing the polyester resin composition.

  The divalent metal element may be added before the first step as long as the element has a transesterification catalytic ability. Moreover, if it is an element which has a polymerization reaction catalytic ability, you may add before the 1st or 2nd process.

  As a method of incorporating a phosphorus element and a sulfur element into a polyester resin composition, a phosphorus compound and a sulfur compound are dissolved in ethylene glycol in advance, mixed, and added before the first or second step. Is preferable from the viewpoint of heat resistance and suppression of foreign matter generation. The kind of the solvent and dispersion medium at this time is the same as the alkylene glycol same as the C2-C4 linear alkylene glycol contained in the polyester resin composition of the present invention. To preferred. If different types of alkylene glycol are used, they may be copolymerized and heat resistance may be reduced.

  In particular, it is preferable to adjust the pH of the mixed liquid of the phosphorus compound and the sulfur compound to an acidity of 2.0 or more and 6.0 or less from the viewpoint of suppressing foreign matter formation. More preferably, it is 4.0 or more and 6.0 or less.

  In the case where the phosphorus compound and sulfur compound are added before the second step, it is preferable from the viewpoint of polymerization reactivity that these phosphorus compound and sulfur compound are added with an addition interval of 5 minutes or more from the polymerization catalyst. As long as the polymerization catalyst is added at an interval of 5 minutes or more, the phosphorus compound and the sulfur compound may be added after or before the addition of the polymerization catalyst.

  On the other hand, various particles may be added to add film slipperiness, or internal precipitation particles using a catalyst may be included.

  The polymerization reaction can be performed by a known method. Furthermore, in order to reduce the amount of terminal carboxyl groups, the polymerization reaction temperature is preferably set to the melting point of the polyester resin composition + 30 ° C. or lower. In addition, the second step is effected by once completing the chip at a stage where the intrinsic viscosity of the polyester resin is 0.5 dl / g or more and 0.6 dl / g or less, and performing solid phase polymerization as the third step. Is.

  In the third step, it is preferable to perform the solid phase polymerization reaction at a solid phase polymerization temperature of the polyester resin composition having a melting point of −60 ° C. or higher and a melting point of −30 ° C. or lower and a vacuum of 0.3 Torr or lower.

The polyester resin composition of the present invention is a heat-resistant stabilizer, ultraviolet absorber, ultraviolet stabilizer, organic / inorganic lubricant, organic / inorganic system as long as the effects of the present invention are not impaired as necessary. Additives such as fine particles, fillers, nucleating agents, dispersing agents and coupling agents may be blended.
The polyester resin composition of the present invention is preferably used as a biaxially oriented polyester film from the viewpoints of orientation and heat resistance and chemical resistance.

  Next, the manufacturing method of the film which uses the polyester composition of this invention is demonstrated. In order to obtain a polyester film having a high intrinsic viscosity and a low amount of terminal carboxyl groups, it is preferable to have the following fourth step after the third step.

  The fourth step is a step of obtaining a film using the polyester resin composition.

  When the film of the present invention has a single film structure, a dried raw material (polyester composition, etc.) is heated and melted in an extruder as needed, and extruded from a die cooled onto a cast drum (melting method). Cast method) can be used. As another method, the raw material is dissolved in a solvent, and the solution is extruded from a die onto a support such as a cast drum or an endless belt to form a film, and then the solvent is dried and removed from the film layer to form a sheet. A method (solution casting method) or the like can also be used.

  Moreover, you may use the polyester resin composition of this invention, the polyester resin composition different from it, etc. as a raw material thrown into an extruder. In the latter case, different polyester resin compositions are melt-kneaded in the extruder, and the melt-kneaded body becomes the polyester composition resin composition of the present invention. And the polyester resin composition of this invention shape | molded in the sheet form can be obtained by extruding this by said method.

  When the film is produced by the melt casting method, the dried raw material is melt-extruded from the die into a sheet using an extruder, and solidified by cooling and solidifying by static electricity on a drum cooled to a surface temperature of 10 ° C. or more and 60 ° C. or less, An unstretched sheet is produced. A biaxially oriented film of the polyester resin composition of the present invention can be obtained by biaxially stretching this unstretched sheet.

  When performing melt extrusion in an extruder, it is better that the time from melting in a nitrogen atmosphere to supplying chips to the extruder and extruding with a die is as short as possible. As a guideline, it is 30 minutes or less, more preferably 15 minutes. In the following, it is more preferable to set it to 5 minutes or less from the viewpoint of suppressing increase in the amount of terminal carboxyl groups.

  The obtained unstretched sheet is biaxially stretched at a temperature equal to or higher than Tg of the polyester resin composition. As a biaxial stretching method, in addition to a sequential biaxial stretching method in which stretching in the longitudinal direction of the film and stretching in the width direction of the film (direction perpendicular to the longitudinal direction of the film) is performed, Examples thereof include a simultaneous biaxial stretching method in which stretching is performed simultaneously.

  In order to complete the crystal orientation of the obtained biaxially stretched film and to impart flatness and dimensional stability, heat treatment is performed for 1 second to 30 seconds at a temperature of Tg or more and less than Tm, and after uniform annealing By cooling to room temperature, a biaxially oriented polyester film is obtained.

  The polyester film of the present invention is preferably produced by a method including the following fifth step and sixth step in this order from the viewpoint of mechanical properties and heat and moisture resistance.

  The fifth step is a step of sequentially biaxially stretching the polyester composition molded into a sheet shape at a temperature of Tg or more and Tg + 40 ° C. or less at an area magnification of 12 times or more (where Tg is obtained by differential scanning calorimetry). The glass transition temperature (° C.) of the polyester composition)).

The sixth step is a step of obtaining a biaxially oriented film of the polyester resin composition by performing heat treatment within the range satisfying the following formula (a) after the fifth step.
(A) 20 ° C. ≦ Tm−Th ≦ 90 ° C.
(Here, Tm is the melting point (° C.) of the polyester composition obtained by differential scanning calorimetry, and Th is the heat treatment temperature (° C.)).

  When the stretching temperature is Tg or less, stretching cannot be performed. Moreover, since it cannot align a film when it exceeds Tg + 40 degreeC, it is unpreferable. If the surface magnification is less than 12 times, the orientation is not sufficient and the heat and moisture resistance is poor. If the heat treatment temperature is high and the formula (a) is not satisfied, the crystallization degree becomes high, the crystallization in a moist heat atmosphere is promoted, and the heat and humidity resistance is poor. If the heat treatment temperature is low and the formula (a) is not satisfied, the thermal dimensional stability is poor. The film of this invention can be made into the biaxially oriented film excellent in heat-and-moisture resistance by manufacturing with the method which contains the said 5th and 6th process in this order.

  In the biaxially oriented polyester film of the present invention, it is preferable from the viewpoint of heat resistance that the time required for the strength retention in the 180 ° C. dry heat test to be 50% or less is 450 hours or more. More preferably, it is 500 hours or more, More preferably, it is 550 hours or more, Especially preferably, it is 600 hours or more. When it is less than 450 hours, when used for electrical insulation applications such as motor parts, the film is rapidly deteriorated and there may be a problem in durability.

The biaxially oriented polyester film of the present invention can be preferably used for electrical insulation from the viewpoint of excellent heat resistance and chemical resistance.
[Characteristic measurement method and effect evaluation method]
A. Chemical resistance (A-1) Weight reduction rate in chemical resistance test The polyester resin composition was molded into a film having a thickness of 1.0 mm and cut into a size of 10 cm × 10 cm. The number of samples was n = 3.

  Based on JIS-K7114 (2001), the weight of the cut sample before the chemical resistance test was measured. The average value of the weights of the samples was determined, and the weight of the average value was M0.

  Next, the film sample was immersed in 500 mL of xylene and treated for 16 hours at a temperature of 140 ° C. in a nitrogen atmosphere.

After completion of the immersion treatment, the film was dried in a vacuum dryer at a temperature of 180 ° C. for 4 hours, and then the weight of the film sample was measured. The average value of the weights of the film samples was determined, and the average value was defined as the weight M1 after the chemical resistance test.
Using the obtained weight M0 before the chemical resistance test and weight M1 after the chemical resistance test, the weight reduction rate was calculated by the following equation (a).
(A) Weight reduction rate (%) = (M0−M1) / M1 × 100
(A-2) Haze change amount in chemical resistance test The polyester resin composition was molded into a film having a thickness of 1.0 mm and cut into a size of 10 cm × 10 cm. The number of samples was n = 3. And based on JIS-K7105 (1981), it measured using fully automatic direct reading haze computer HGM-2DP (made by Suga Test Instruments Co., Ltd.). This was repeated 10 times at random. The average value of the haze values of the samples was determined, and the haze value of the average value was defined as H0. Next, based on JIS-K7114 (2001), the said film sample was immersed in 500 mL of xylene, and the process was performed for 16 hours under temperature 140 degreeC and nitrogen atmosphere.

  After the immersion treatment, the haze value after the immersion was measured. This was repeated 10 times at random. The average value of the haze values of the samples was determined, and the haze value of the average value was defined as H1.

  Using the obtained haze value H0 before immersion and haze value H1 after immersion, the haze value change amount ΔH was calculated by the following equation (b).

(B) ΔH (%) = H1−H0
From the obtained haze value change amount ΔH, the chemical resistance of the film was determined as follows.

Haze value change amount ΔH is 2% or less: A
Haze value change amount ΔH is more than 2% and not more than 5%: B
Haze value change amount ΔH is more than 5% and 10% or less: C
Haze value change amount ΔH exceeds 10%: D
A to C are good, and A is the best among them.

B. Phosphorus element, sulfur element and metal element (excluding alkali metal element) contained in the polyester resin composition Measured using a fluorescent X-ray analyzer (model number: 3270) manufactured by Rigaku Corporation.

C. Content of alkali metal element of polyester composition Measured by an atomic absorption analysis method (manufactured by Tatetsu Seisakusho: Polarized Zeeman atomic absorption photometer 180-80, frame: acetylene-air).

D. Intrinsic viscosity of polyester resin IV
The polyester resin composition is dissolved in 100 ml of orthochlorophenol (solution concentration C = 1.2 g / dl), and the viscosity of the solution at 25 ° C. is measured using an Ostwald viscometer. Similarly, the viscosity of the solvent is measured. Using the obtained solution viscosity and solvent viscosity, [η] (dl / g) is calculated by the following formula (c), and the obtained value is used as the intrinsic viscosity (IV).
(C) ηsp / C = [η] + K [η] ² · C (where ηsp = (solution viscosity (dl / g) / solvent viscosity (dl / g)) − 1, and K is a Huggins constant (0. 343)).

E. The amount of terminal carboxyl groups of the polyester composition is measured under the following conditions in accordance with the method of Malice (document MJ Malice, F. Huizinga, Anal. Chim. Acta, 22 363 (1960)). 2 g of the polyester composition was dissolved in 50 mL of o-cresol / chloroform (weight ratio 7/3) at a temperature of 150 ° C., titrated with a 0.05N KOH / methanol solution, the amount of terminal carboxyl groups was measured, eq. / Indicated by the value of polyester 1t. In addition, the indicator at the time of titration uses phenol red, and the place where it changed from yellowish green to light red is set as the end point of titration.

F. Thermal decomposition weight reduction rate at 300 ° C in thermogravimetry (heat resistance)
In an environment of 25 ° C. and a relative humidity of 65% RH, 15.00 mg of the polyester film was allowed to stand for 24 hours.

Next, using a TGA apparatus (TGA-50, manufactured by Shimadzu Corporation), a thermal load of the film was applied under the following conditions, and the weight reduction rate of the polyester film before and after the test was measured.
Gas: Nitrogen gas Flow rate: 20 ml / min Starting temperature: 25 ° C.
End temperature: 300 ° C
Temperature rising rate: 10 ° C./min End temperature holding time: 30 minutes Weight G (mg) after the test was weighed, and the thermal decomposition weight reduction rate T (mass%) at 300 ° C. in thermogravimetry was calculated as follows: Calculated by equation (d).
(D) T (mass%) = (15−G) × 100/15
G. Heat resistance of polyester film The film is cut into a size of 1 cm x 20 cm and the long side is parallel to the longitudinal direction and the width direction of the film, respectively. Based on ASTM-D882 (1997), 5 cm between chucks, pulling speed The breaking strength when pulled at 300 mm / min is measured. The number of samples is n = 5, and after measuring in the longitudinal direction and the width direction of the film, the average value thereof is obtained, and this is set as the breaking strength E0 of the film.

Next, the film cut in the same manner is subjected to a dry heat treatment under a high temperature condition of 180 ° C. in a gear oven manufactured by Tabai Espec Co., Ltd., and then the breaking strength is measured. In addition, it is set as n = 5 and it measures about each of the longitudinal direction of a film, and the width direction, and let the average value be breaking strength E1. Using the obtained breaking strengths E0 and E1, the strength retention is calculated by the following equation (e). The treatment time was changed by 1 hour, and the time required for the strength retention to be 50% or less was determined.
(E) Strength retention (%) = E1 / E0 × 100
From the time required for the obtained strength retention to be 50% or less, the heat resistance of the film was determined as follows.
When the time required for the strength retention to be 50% or less is 600 hours or more: A
When the time required for the strength retention to be 50% or less is 550 hours or more and less than 600 hours: B
When the time required for the strength retention to be 50% or less is 500 hours or more and less than 550 hours: C
When the time required for the strength retention to be 50% or less is 450 hours or more and less than 500 hours: D
When the time required for the strength retention to be 50% or less is less than 450 hours: E
A to C are good, and A is the best among them.

  When the longitudinal direction and the width direction of the film are not known, the direction having the maximum refractive index in the film is regarded as the longitudinal direction, and the direction perpendicular to the longitudinal direction is regarded as the width direction. In addition, the direction of the maximum refractive index in the film may be obtained by measuring the refractive index in all directions of the film with an Abbe refractometer, for example, by using a phase difference measuring device (birefringence measuring device) or the like. You may obtain | require by determining an axial direction.

H. Glass transition temperature (Tg)
In accordance with JIS K7121 (1999), a differential scanning calorimeter “Robot DSC-RDC220” manufactured by Seiko Denshi Kogyo Co., Ltd. was used, and a disk session “SSC / 5200” was used for data analysis. Perform the measurement.

  5 mg of a sample is weighed in a sample pan, and the sample is heated from 25 ° C. to 300 ° C. at a heating rate of 20 ° C./min (1stRUN), held in that state for 5 minutes, and then rapidly cooled to 25 ° C. or lower. Immediately thereafter, the temperature was increased again from 25 ° C. to 300 ° C. at a rate of temperature increase of 20 ° C./minute, and a 2ndRUN differential scanning calorimetry chart (the vertical axis represents thermal energy and the horizontal axis represents temperature) Get. In the 2ndRUN differential scanning calorimetry chart, in the step change portion of the glass transition, a straight line that is equidistant from the extended straight line of each base line in the vertical axis direction and a curve of the step change portion of the glass transition are Find from the point of intersection. When two or more stepwise changes in glass transition are observed, the glass transition temperature is obtained for each, and the average of these temperatures is taken as the glass transition temperature (Tg) (° C.) of the sample.

I. Melting point (Tm)
In accordance with JIS K7121 (1999), a differential scanning calorimeter “Robot DSC-RDC220” manufactured by Seiko Denshi Kogyo Co., Ltd. was used, and a disk session “SSC / 5200” was used for data analysis. Perform the measurement.

  5 mg of a sample is weighed in a sample pan, and the sample is heated from 25 ° C. to 300 ° C. at a heating rate of 20 ° C./min (1stRUN), held in that state for 5 minutes, and then rapidly cooled to 25 ° C. or lower. Immediately thereafter, the temperature is raised again from 25 ° C. to 300 ° C. at a rate of temperature increase of 20 ° C./min to obtain a 2ndRUN differential scanning calorimetry chart (vertical axis is thermal energy and horizontal axis is temperature). In the differential scanning calorimetry chart of 2ndRun, the temperature of the peak top at the crystal melting peak, which is the endothermic peak, is obtained, and this is defined as Tm (° C.). When two or more crystal melting peaks are observed, the temperature of the peak top having the lowest temperature is defined as Tm (° C.).

J. et al. Crystallization temperature (Tc)
In accordance with JIS K7121 (1999), a differential scanning calorimeter “Robot DSC-RDC220” manufactured by Seiko Denshi Kogyo Co., Ltd. was used, and a disk session “SSC / 5200” was used for data analysis. Perform the measurement.

  5 mg of a sample is weighed in a sample pan, and the sample is heated from 25 ° C. to 300 ° C. at a heating rate of 20 ° C./min (1stRUN), held in that state for 5 minutes, and then rapidly cooled to 25 ° C. or lower. Immediately thereafter, the temperature is raised again from 25 ° C. to 300 ° C. at a rate of temperature increase of 20 ° C./min to obtain a 2ndRUN differential scanning calorimetry chart (vertical axis is thermal energy and horizontal axis is temperature). From the differential scanning calorimetry chart of 2ndRUN, the temperature is obtained as the peak top temperature of the crystallization peak, which is an exothermic peak at the time of temperature rise, and this is defined as the crystallization temperature (Tc) (° C.). When two or more crystallization peaks are observed, the crystallization temperature is obtained from the peak top temperature of each peak, and the average of these temperatures is taken as the crystallization temperature (Tc) (° C.) of the sample.

K. Polymerization suitability
The polymerization reaction is started at a polymerization reaction start temperature of 230 ° C., and the temperature is raised to a final polymerization reaction temperature of 285 ° C. at a degree of vacuum of 0.1 Torr, a stirring speed of 30 rpm / min, and a temperature increase rate of 0.5 ° C./min. Polymerization suitability was determined by the time required for the intrinsic viscosity to reach 0.52 dl / g.
The time for the intrinsic viscosity in the polymerization reaction to reach 0.52 dl / g is 2 hours or less: A
The time for the intrinsic viscosity in the polymerization reaction to reach 0.52 dl / g is more than 2 hours and not more than 2 hours 30 minutes: B
The time for the intrinsic viscosity in the polymerization reaction to reach 0.52 dl / g is more than 2 hours 30 minutes but not more than 3 hours: C
The time for the intrinsic viscosity in the polymerization reaction to reach 0.52 dl / g exceeds 3 hours: D
A to C are good, and A is the best among them.

  The present invention will be described more specifically based on examples. However, the present invention is not limited to the following examples.

Example 1
First step: 100 parts by mass of dimethyl terephthalate, 57.5 parts by mass of ethylene glycol, and 0.0147 parts by mass of manganese acetate tetrahydrate were melted at 150 ° C. in a nitrogen atmosphere. While stirring this melt, the temperature was raised to 230 ° C. over 3 hours to distill methanol, thereby completing the transesterification reaction.
Second step: After the transesterification reaction, tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene diphosphite (manufactured by Clariant, Hostanox P-EPQ), which is a phosphorus antioxidant 0.47 parts by mass (phosphorus element equivalent: 5.8 mol / t) and sulfur-based antioxidant pentaerythritol-tetrakis- (β-lauryl-thio-propionate) (manufactured by ADEKA, AO-412S) 183 parts by mass (4.0 mol / t in terms of sulfur element) and 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4 as a phenolic antioxidant) -Hydroxybenzyl) benzene (manufactured by ADEKA, AO-330) was added in an amount of 0.2 parts by mass (4.9 mol / t in terms of hindered phenol structure), and after 5 minutes. A mixture of 0.03 parts by mass of antimony trioxide in 1.6 parts by mass of ethylene glycol was added to the mixture. Polymerization was started at a polymerization reaction starting temperature of 230 ° C. and a degree of vacuum of 0.1 Torr. The obtained polyester resin composition had an intrinsic viscosity of 0.52 dl / g and a terminal carboxyl group amount of 15 eq. / Ton.
Third step: The polyester resin composition obtained in the previous step was placed under vacuum at 160 ° C. for 6 hours to dry and crystallize the polyester resin composition. Thereafter, this was placed under vacuum at 220 ° C. for 8 hours for solid phase polymerization to obtain a polyester resin composition. The obtained polyester resin composition had an intrinsic viscosity of 0.69 dl / g and a terminal carboxyl group amount of 15 eq. / Ton.

  The polyethylene resin composition after the third step (solid phase polymerization) was supplied to an extruder under a nitrogen atmosphere. It was discharged from a T die at an extrusion temperature of 280 ° C., quenched with a casting drum (20 ° C.), and formed into a sheet by an electrostatic application method. This sheet was longitudinally stretched at a longitudinal stretching temperature of 90 ° C. and a longitudinal stretching ratio of 3.6 times, and then stretched at a transverse stretching temperature of 110 ° C. and a transverse stretching ratio of 3.6 times. A stretched polyester film was obtained.

At this time, a 400-mesh wire mesh was used as the filter of the extruder. Further, the residence time was about 5 minutes from the supply of the polymer to the discharge from the T die.

  The characteristics of the obtained polyester resin composition (polyester resin composition biaxially oriented film) are shown in the table.

(Example 2-27 Comparative example 1-32)
A polyester resin composition (polyester resin composition) in the same manner as in Example 1 except that the amount of phosphorus element contained in the polyester resin composition, the amount of sulfur element, the amount of phenolic antioxidant added, and the type were changed. Biaxially oriented film) was obtained. The characteristics of the obtained polyester resin composition (polyester resin composition biaxially oriented film) are shown in the table.

(Examples 28-31)
A polyester resin composition (polyester resin composition biaxially oriented film) was prepared in the same manner as in Example 1 except that the phosphorus element amount, sulfur element amount and manganese acetate contained in the polyester resin composition were changed to calcium acetate. Obtained. However, as the raw material, the polyester resin composition was not used as it was, but a raw material adjusted so that the composition of the finally obtained polyester resin composition was as shown in the table was used. For example, in the example in which Ca element is contained in the film, calcium acetate was used in place of all or part of manganese acetate used as a raw material in the production of the polyester resin composition. Moreover, in the Example which changed content of each component in a polyester resin composition, the addition amount of each raw material used in the case of manufacture of a polyester resin composition was adjusted.

(Example 32)
First step: 100 parts by mass of dimethyl terephthalate, 57.5 parts by mass of ethylene glycol, and 0.0147 parts by mass of manganese acetate tetrahydrate were melted at 150 ° C. in a nitrogen atmosphere. While stirring this melt, the temperature was raised to 230 ° C. over 3 hours to distill methanol, thereby completing the transesterification reaction.
Second step: After completion of the transesterification reaction, a mixture of 0.03 parts by mass of antimony trioxide in 1.6 parts by mass of ethylene glycol was added. The polymerization conditions in the second step were as follows: polymerization was started at a polymerization reaction start temperature of 230 ° C., the degree of vacuum was 0.1 Torr, the stirring speed was 30 rpm / min, the temperature increase rate was 0.5 ° C./min, and the final temperature of the polymerization reaction was 285. C. The obtained polyester resin composition had an intrinsic viscosity of 0.52 dl / g and a terminal carboxyl group amount of 15 eq. / Ton.
Third step: The polyester resin composition obtained in the previous step was placed under vacuum at 160 ° C. for 6 hours to dry and crystallize the polyester resin composition. Thereafter, this was placed under vacuum at 220 ° C. for 8 hours for solid phase polymerization to obtain a polyester resin composition. The obtained polyester resin composition had an intrinsic viscosity of 0.69 dl / g and a terminal carboxyl group content of 15 eq. / Ton.
Fourth step: The polyester resin composition obtained in the previous step and tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene diphosphite (manufactured by Clariant, 0.47 parts by mass (Hostanox P-EPQ) (5.8 mol / t in terms of phosphorus element) and pentaerythritol-tetrakis- (β-lauryl-thio-propionate) which is a sulfur-based antioxidant (manufactured by ADEKA, AO -412S) in 0.183 parts by mass (4.0 mol / t in terms of sulfur element) and 1,3,5-trimethyl-2,4,6-tris (3,5-di-) as a phenolic antioxidant. 0.2 part by mass (4.9 mol / t in terms of hindered phenol structure) of t-butyl-4-hydroxybenzyl) benzene (manufactured by ADEKA, AO-330) Was put into an extruder. A polyester resin composition was obtained by melt-kneading at an extruder temperature of 280 ° C.
The polyester resin composition after the fourth step was supplied to the extruder under a nitrogen atmosphere. It was discharged from a T die at an extrusion temperature of 280 ° C., quenched with a casting drum (20 ° C.), and formed into a sheet by an electrostatic application method. This sheet was longitudinally stretched at a longitudinal stretching temperature of 90 ° C. and a longitudinal stretching ratio of 3.6 times, and then stretched at a transverse stretching temperature of 110 ° C. and a transverse stretching ratio of 3.6 times. A stretched film was obtained.

At this time, a 400-mesh wire mesh was used as the filter of the extruder. Further, the residence time was about 5 minutes from the supply of the polymer to the discharge from the T die.
The characteristics of the obtained polyester resin composition (polyester resin composition biaxially oriented film) are shown in the table.

In the table, the following compounds are described as a to f in the terms of phosphorus-based antioxidant, sulfur-based antioxidant, and phenol-based antioxidant.
(Phosphorus antioxidant)
a: Tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene diphosphite (manufactured by Clariant, Hostanox P-EPQ)
b: 2,2′-bis (2,6-di-t-butyl-4-methylphenoxy) -5,5′-spirobi [1,3,2-dioxaphosphorinane] (manufactured by ADEKA, PEP- 36)
c: Tris (2,4-di-t-butylphenyl) phosphite (manufactured by ADEKA, 2112)
(Sulfur-based antioxidant)
d: Pentaerythritol-tetrakis- (β-lauryl-thio-propionate) (manufactured by ADEKA, AO-412S)
(Phenolic antioxidant)
e: 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (manufactured by ADEKA, AO-330)
f: 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetra Oxaspiro [5.5] Undecane (Sumitomo Chemical Co., Ltd., SUMILIZER GA-80)

The polyester resin composition of the present invention is excellent in heat resistance and chemical resistance. In addition, the biaxially stretched film of the polyester resin composition of the present invention is suitable for applications such as magnetic materials, solar cells, and packaging, especially for electrical insulation that requires heat resistance and chemical resistance. Can be used for

Claims (12)

A polyester resin composition that satisfies the following requirements (1) to (4).
(1) When the polyester resin composition contains phosphorus element and the phosphorus element contained in the polyester resin composition is P (mol / t), the following formula (i) is satisfied.
(I) 2.5 ≦ P ≦ 17.5
(2) The polyester resin composition further contains a sulfur element, and when the sulfur element contained in the polyester resin composition is S (mol / t), the following formula (ii) is satisfied.
(Ii) 4.0 ≦ P + S ≦ 28.5
(3) The polyester resin composition contains a divalent metal element, and satisfies the following formula (iii) when the amount of the divalent metal element in the polyester resin composition is M (mol / t). .
(Iii) 0.03 ≦ M / (P + S) ≦ 1.30
(4) The weight reduction rate in the chemical resistance test is 1.0% by weight or less. The polyester resin composition according to claim 1, wherein the following requirements (5) to (6) are satisfied.
(5) The polyester resin composition is a polyester resin composition obtained by adding a phosphorus-based antioxidant and a sulfur-based antioxidant.
(6) The divalent metal element contained in the polyester resin composition is at least one selected from Ca element and Mn element. The polyester resin composition according to claim 2, wherein the phosphorus antioxidant is a phosphite antioxidant. When the polyester resin composition is a polyester resin composition obtained by adding a phenolic antioxidant and the amount of the phenolic antioxidant added is PH (mol / t), the following formula (iv) The polyester resin composition according to claim 1, wherein the polyester resin composition is satisfied.
(Iv) 1.8 ≦ PH ≦ 9.0 The polyester resin composition according to claim 4, wherein the phenolic antioxidant is a hindered phenolic antioxidant. The polyester resin composition according to claim 4 or 5, wherein the following formula (v) is satisfied.
(V) 0.02 ≦ M / (P + S + PH) ≦ 0.87 The polyester resin composition according to any one of claims 1 to 6, wherein the intrinsic viscosity is in a range of 0.6 dl / g or more and 1.0 dl / g or less. The amount of terminal carboxyl groups is 20 eq / ton or less, The polyester resin composition in any one of Claims 1-7 characterized by the above-mentioned. The polyester resin composition according to any one of claims 1 to 8, wherein a thermal decomposition weight reduction rate at 300 ° C in thermogravimetry is 0.5% by weight or less. The biaxially-oriented polyester film using the polyester resin composition in any one of Claims 1-9. The biaxially oriented polyester film according to claim 10, wherein the time required for the strength retention to be 50% or less in a 180 ° C dry heat test is 450 hours or more. The biaxially oriented polyester film according to claim 10 or 11, which is used for electrical insulation.