Polyester resin composition, film and method for producing polyester resin composition

Abstract

To provide a polyester resin composition with a low content of foreign matter derived from catalyst elements, and a method for producing the same.MEANS FOR ACHIEVING THE PURPOSE: A polyester resin composition includes an organic germanium compound with Ge-C bonds and Ge-O bonds.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polyester resin composition, a film, and a method for producing a polyester resin composition. [Background technology]

[0002] Polyesters have excellent mechanical properties, thermal properties, chemical resistance, electrical properties, and moldability, and are used in a variety of applications. Among polyesters, polyethylene terephthalate (hereinafter referred to as PET) in particular has excellent transparency and processability, and is therefore widely used in applications that require high quality, such as optical films and release films.

[0003] In general, a polyester resin composition, particularly PET, is produced by producing an esterification reaction product from a dicarboxylic acid such as terephthalic acid or an ester-forming derivative thereof and ethylene glycol or a glycol mainly composed of ethylene glycol, and then polycondensing the esterification reaction product at high temperature and high vacuum in the presence of a polycondensation catalyst.

[0004] Germanium compounds, titanium compounds, antimony compounds, etc. have been used as polycondensation catalysts in the production of polyester resin compositions, but antimony compounds, which are inexpensive and have excellent catalytic activity, are most widely used. However, when antimony compounds are used as polycondensation catalysts, they tend to precipitate as insoluble metal particles during the production stage of PET, which causes defects when the final PET is molded. In recent years, the quality requirements for optical films and release films have become increasingly high, and a technology is desired that suppresses the above-mentioned defects while maintaining mechanical and thermal properties. In light of the above background, polyesters with low or no antimony content are required. In response to these issues, studies have been conducted as shown in the following documents.

[0005] Patent Document 1 discloses a technique for suppressing the production of metallic antimony by reducing the amount of antimony compound added.

[0006] Patent Document 2 discloses a method for producing polyester in which specific amounts of a manganese compound, an alkali metal compound, a phosphorus compound, and an organotitanium compound are used to suppress the formation of insoluble foreign matter in the polymer.

[0007] Patent Document 3 discloses a technique for improving the transparency and crystallinity of polyester by using a magnesium compound and a phosphorus compound in the presence of a germanium compound as a catalyst. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 3-146707 [Patent Document 2] Japanese Patent Application Publication No. 63-278927 [Patent Document 3] JP 2003-137992 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, although Patent Document 1 reduced the generation of metallic antimony, it was impossible to completely eliminate it because it contained an antimony compound. Patent Document 2 had a problem that the titanium compound was highly active, and changed and aggregated during the polyester polymerization reaction, generating foreign matter. Patent Document 3 had a problem that if a metal compound or phosphorus compound suitable for the germanium compound was not added, the decomposition of the polyester was promoted and the heat resistance was deteriorated. As described above, it was difficult to obtain a polyester in which foreign matter was reduced to the utmost while maintaining heat resistance. In addition, germanium dioxide, which is generally used as a germanium compound, has low solubility, so that the storage stability as a catalyst solution is low and precipitation occurs, leading to the generation of foreign matter.

[0010] An object of the present invention is to provide a polyester resin composition containing little foreign matter derived from catalytic elements, and a method for producing the same. [Means for solving the problem]

[0011] As a result of investigations aimed at solving the above problems, the present inventors discovered a polyester resin composition which uses an organogermanium compound as a catalyst and which has less foreign matter derived from the catalyst element, and a method for producing the same, thereby arriving at the present invention.

[0012] The object of the present invention is achieved by the following means. (1) A polyester resin composition containing an organogermanium compound having a Ge-C bond and a Ge-O bond. (2) The polyester resin composition according to claim 1, wherein the organogermanium compound has a structure represented by Chemical Formula 1.

[0013] [ka]

[0014] R1 is a functional group bonded to a Ge element via a C element, and may include an alkyl group, a carboxyl group, a hydroxyl group, or an alkoxy group. R2 is a functional group bonded to an O element via an element selected from a C element, a Ge element, an O element, and an H element. (3) The polyester resin composition according to (1), wherein the organogermanium compound has a structure represented by Chemical Formula 2.

[0015] [ka]

[0016] R3 and R4 are functional groups bonded to the Ge element via the C element, and may include an alkyl group, a carboxyl group, a hydroxyl group, or an alkoxy group. (4) The polyester resin composition according to (1), wherein the content of germanium element in the polyester resin composition is 3 ppm by mass or more and 100 ppm by mass or less. (5) The polyester resin composition according to (1), wherein the content of phosphorus element is 5 ppm by mass or more and 200 ppm by mass or less based on the polyester resin composition. (6) The polyester resin composition according to (1), wherein the organogermanium compound is bis[2-carboxyethylgermanium(IV)]sesquioxide. (7) The polyester resin composition according to claim 1, wherein the polyester is polyethylene terephthalate. (8) A polyester film comprising the polyester resin composition of (1). (9) A release polyester film comprising the polyester resin composition of (1). (10) A release film comprising the polyester resin composition of (1) used as a film for a dry film resist support. (11) A method for producing a polyester resin composition, comprising carrying out an esterification reaction between a dicarboxylic acid component and a diol component, or an ester exchange reaction between a dicarboxylic acid ester-forming derivative component and a diol component, followed by a polycondensation reaction to produce a polyester, and adding an organogermanium compound having a Ge-C bond and a Ge-O bond when the IV (intrinsic viscosity) of the polyester is 0.4 or less. (12) The method for producing a polyester resin composition according to (11), wherein the organogermanium compound has a structure represented by Chemical Formula 1.

[0017] [ka]

[0018] (13) The method for producing a polyester resin composition according to (11), wherein the organogermanium compound has a structure of (Chemical Formula 2).

[0019] [ka]

[0020] (14) The method for producing a polyester resin composition according to (11), wherein the content of germanium element in the polyester resin composition is 3 ppm by mass or more and 100 ppm by mass or less. (15) The method for producing a polyester resin composition according to (11), wherein the content of phosphorus element in the polyester resin composition is 5 ppm by mass or more and 200 ppm by mass or less. (16) The method for producing a polyester resin composition according to (11), wherein the organogermanium compound is bis[2-carboxyethylgermanium(IV)]sesquioxide. (17) The method for producing a polyester resin composition according to (11), wherein the polyester is polyethylene terephthalate. Effect of the Invention

[0021] The present invention provides a polyester resin composition containing little foreign matter derived from catalytic elements, a film, and a method for producing the polyester resin composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present invention will be described in detail below. In the present invention, the term "element" may be used synonymously with the term "atom."

[0023] The polyester resin composition in the present invention refers to a polyester resin obtained by polycondensation of a dicarboxylic acid component and a diol component.

[0024] As the dicarboxylic acid component in the present invention, various dicarboxylic acid components such as aromatic dicarboxylic acid, linear aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, etc. can be used. Among them, aromatic dicarboxylic acid and its ester-forming derivative components are preferable from the viewpoint of mechanical properties, heat resistance, and hydrolysis resistance of the polyester resin composition. In particular, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and their ester-forming derivative components are preferable from the viewpoint of polymerizability and mechanical properties.

[0025] As the diol component in the present invention, various diols can be used. For example, aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, and neopentyl glycol, and alicyclic diols such as cyclohexanedimethanol and cyclohexanediethanol, and aromatic diols such as bisphenol A, bisphenol S, styrene glycol, 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, and 9,9'-bis(4-hydroxyphenyl)fluorene can be used. In addition to diols, polyfunctional alcohols such as trimethylolpropane and pentaerythritol can also be used.

[0026] Among these, diols having a boiling point of 230° C. or less are preferred because they can be easily distilled out of the polymerization reaction system, and aliphatic diols are more preferred because they are low cost and highly reactive. Furthermore, ethylene glycol is particularly preferred from the viewpoint of mechanical properties. In addition, other dicarboxylic acid components, hydroxycarboxylic acid derivatives, and diol components may be copolymerized to the extent that the effect of the present invention is not impaired.

[0027] The polyester resin composition of the present invention must contain an organogermanium compound having a Ge-C bond and a Ge-O bond. It is preferable that the organogermanium compound has the structure shown in Chemical Formula 1.

[0028] [ka]

[0029] R1 is a functional group bonded to a Ge element via a C element, and may include an alkyl group, a carboxyl group, a hydroxyl group, or an alkoxy group. R2 is a functional group bonded to an O element via an element selected from a C element, a Ge element, an O element, and an H element.

[0030] More preferably, the compound is an organogermanium compound having the structure shown in Chemical Formula 2.

[0031] [ka]

[0032] R3 and R4 are functional groups bonded to the Ge element via the C element, and may include an alkyl group, a carboxyl group, a hydroxyl group, or an alkoxy group.

[0033] Specifically, bis[2-carboxyethylgermanium(IV)]sesquioxide, trimethylgermanium methoxide, dimethylgermanium diacetate, etc. can be mentioned, but are not limited to these. These compounds have superior solubility in solvents compared to inorganic germanium such as germanium dioxide, and therefore have a foreign matter suppression effect. In addition, bis[2-carboxyethylgermanium(IV)]sesquioxide is the most preferable because it has sufficient polymerization activity and can produce a polymer with excellent color tone.

[0034] The polyester resin composition of the present invention preferably contains germanium element in an amount of 3 ppm by mass or more and 100 ppm by mass or less based on the weight of the polyester resin composition. The lower limit is preferably 5 ppm by mass or more. The upper limit is preferably 70 ppm by mass or less, more preferably 50 ppm by mass or less. The germanium compound is used as a polymerization catalyst for polyester, and by making the amount equal to or more than the lower limit, it is possible to proceed with the polycondensation reaction without delay. In addition, the germanium element has excellent catalytic activity, and if it is present in excess, it contributes to the thermal decomposition, oxidative decomposition, and hydrolysis of polyester. Therefore, by satisfying the amount of germanium element equal to or less than the upper limit, it is possible to suppress various decompositions.

[0035] In addition, the polyester resin composition of the present invention preferably contains phosphorus element in an amount of 5 ppm by mass or more and 200 ppm by mass or less based on the weight of the polyester resin composition. The lower limit is preferably 7 ppm by mass or more, more preferably 10 ppm by mass or more. The upper limit is preferably 150 ppm by mass or less, more preferably 100 ppm by mass or less. By setting it in the above range, it is possible to improve heat resistance without impairing polymerization reactivity.

[0036] The polyester constituting the polyester resin composition of the present invention is preferably PET in terms of sufficient heat resistance, and may contain a copolymerization component within a range that does not impair the effects of the present invention.

[0037] Next, a method for producing the polyester resin composition of the present invention will be described. The polyester resin composition of the present invention can be obtained by carrying out an esterification reaction between a dicarboxylic acid component and a diol component, or an ester exchange reaction between a dicarboxylic acid ester-forming derivative component and a diol component, followed by a polycondensation reaction to produce a polyester, and adding an organogermanium compound having a Ge-C bond and a Ge-O bond at a stage when the IV (intrinsic viscosity) of the polyester is 0.4 or less.

[0038] In the production method of the present invention, the esterification reaction step is a step of esterifying dicarboxylic acid and diol at a predetermined temperature until a predetermined amount of water is distilled to obtain a low polymer. When obtaining a low polymer by esterification reaction, the molar ratio of dicarboxylic acid and diol (diol / dicarboxylic acid) before the start of esterification reaction is preferably in the range of 1.05 to 1.40 from the viewpoint of esterification reactivity and heat resistance. More preferably, it is in the range of 1.05 to 1.30, and even more preferably, it is in the range of 1.05 to 1.20. By setting it in the above range, it has good reactivity, can suppress the generation of by-products such as dimers of diol, and can improve heat resistance.

[0039] The transesterification reaction step is a step of transesterifying a dicarboxylic acid alkyl ester with a diol, and carrying out the reaction until a predetermined amount of alcohol is distilled off to obtain a low polymer. When obtaining a low polymer by transesterification, the molar ratio of the dicarboxylic acid alkyl ester to the diol (diol / dicarboxylic acid alkyl ester) is preferably in the range of 1.7 to 2.3 from the viewpoints of reactivity and heat resistance. By setting the ratio in the above range, the transesterification reaction can be efficiently progressed and the by-production of a dimer of the diol can be suppressed, so that the heat resistance can be improved.

[0040] The polycondensation reaction is a process for obtaining a polyester resin composition from a low polymer obtained by an esterification reaction or an ester exchange reaction.

[0041] The production method of the present invention can be applied to batch polymerization, semi-continuous polymerization, and continuous polymerization.

[0042] In the method for producing the polyester resin composition of the present invention, the catalyst used in the esterification reaction may be a compound such as manganese, cobalt, zinc, titanium, or calcium, but it is preferable to carry out the esterification reaction without a catalyst from the viewpoint of thermal decomposition and generation of foreign matter in the polycondensation reaction stage. Here, the esterification reaction proceeds sufficiently even without a catalyst due to the self-catalytic action of the carboxylic acid. In addition, a known transesterification catalyst can be used as a catalyst used in the transesterification reaction. Examples of the transesterification catalyst include organic manganese compounds, organic magnesium compounds, organic calcium compounds, organic cobalt compounds, and organic lithium compounds, and specific examples thereof include carbonates, acetates, and benzoates, and further include oxides and hydroxides, but are not limited thereto.

[0043] In the method for producing the polyester resin composition of the present invention, it is necessary to add an organogermanium compound having a Ge-C bond and a Ge-O bond. It is preferable to add an organogermanium compound having the structure of (Chemical Formula 1).

[0044] [ka]

[0045] R1 is a functional group bonded to a Ge element via a C element, and may include an alkyl group, a carboxyl group, a hydroxyl group, or an alkoxy group. R2 is a functional group bonded to an O element via an element selected from a C element, a Ge element, an O element, and an H element.

[0046] More preferably, an organogermanium compound having the structure of (Chemical Formula 2) is added.

[0047] [ka]

[0048] R3 and R4 are functional groups bonded to the Ge element via the C element, and may include an alkyl group, a carboxyl group, a hydroxyl group, or an alkoxy group.

[0049] Specifically, bis[2-carboxyethylgermanium(IV)]sesquioxide, trimethylgermanium methoxide, dimethylgermanium diacetate, etc. are included, but are not limited thereto. These compounds have superior solubility in solvents compared to inorganic germanium such as germanium dioxide, and therefore have a foreign matter suppression effect. In addition, bis[2-carboxyethylgermanium(IV)]sesquioxide is the most preferable because it has sufficient polymerization activity and can produce a polymer with excellent color tone. To identify the type of germanium compound contained in the polyester resin composition, it is sufficient to measure the distance between Ge-O elements and Ge-C elements by XAFS or perform Ge NMR measurement.

[0050] In the method for producing a polyester resin composition of the present invention, it is preferable to add germanium element so that the content is 3 ppm by mass or more and 100 ppm by mass or less relative to the weight of the polyester resin composition. The lower limit is preferably 5 ppm by mass or more. The upper limit is preferably 70 ppm by mass or less, more preferably 50 ppm by mass or less. The germanium compound is used as a polymerization catalyst for polyester, and by making it equal to or more than the above lower limit, it is possible to proceed with the polycondensation reaction without delay. In addition, the germanium element has excellent catalytic activity, and if it is present in excess, it contributes to the thermal decomposition, oxidative decomposition, and hydrolysis of polyester. Therefore, by satisfying the amount of germanium element equal to or less than the above upper limit, it is possible to suppress various decompositions of polyester.

[0051] The organic germanium compound having the Ge-C bond and Ge-O bond may be added in the form of powder, slurry, or solution, and is preferably added as a solution from the viewpoint of suppressing foreign matter. The solvent used in this case is preferably the same as the diol component of the polyester resin composition, and in the case of polyethylene terephthalate, ethylene glycol is preferably used. If the compound does not dissolve in ethylene glycol alone, it is recommended to dissolve the compound in an alkaline aqueous solution and then add ethylene glycol. There is no limitation to the alkaline aqueous solution, but a tetraethylammonium hydroxide aqueous solution or a potassium hydroxide aqueous solution can be used.

[0052] In addition, the slurry or solution concentration is preferably 20% by mass or less, more preferably 13% by mass or less, and even more preferably 8% by mass or less, as the concentration of the organogermanium compound having Ge-C bonds and Ge-O bonds in the solution, from the viewpoint of solubility. In addition, the polyester resin composition of the present invention is preferably added with phosphorus element so that the content is 5 ppm by mass or more and 200 ppm by mass or less relative to the weight of the polyester resin composition. The lower limit is preferably 7 ppm by mass or more, more preferably 10 ppm by mass or more. The upper limit is preferably 150 ppm by mass or less, more preferably 100 ppm by mass or less. By setting it in the above range, heat resistance can be imparted to the polyester.

[0053] Examples of compounds containing phosphorus include, but are not limited to, phosphoric acid, phosphoric esters, phosphorous acid, and diethylphosphonoethyl acetate. From the viewpoint of the color tone of the polymer, phosphoric acid is the most preferable. The compound containing phosphorus may be added in the form of a powder, a slurry, or a solution, and is preferably added as a solution from the viewpoint of dispersibility. The solvent used in this case is preferably the same as that of the diol component of the polyester resin composition, and in the case of polyethylene terephthalate, ethylene glycol is preferably used.

[0054] In addition, since the germanium compound and the phosphorus compound are distilled off together with the glycol component during polymerization, it is necessary to adjust the amount added taking into consideration the amount distilled off so as to obtain a preferred content.

[0055] In addition, in the method for producing the polyester resin composition of the present invention, solid-phase polymerization may be performed to obtain a polyester resin composition having a high molecular weight. The solid-phase polymerization is performed by heating the polyester resin composition under an inert gas atmosphere or under reduced pressure, although the apparatus and method are not particularly limited. The inert gas may be any gas inert to the polyester resin composition, such as nitrogen, helium, and carbon dioxide, but nitrogen is preferably used from the viewpoint of economy. In addition, under reduced pressure conditions, it is advantageous to achieve a higher vacuum because it shortens the time required for the solid-phase polymerization reaction, and specifically, it is preferable to maintain the pressure at 110 Pa or less. In addition, when performing a deactivation treatment of the catalyst remaining in the polyester resin, it is preferable to perform the deactivation treatment after the solid-phase polymerization in order to efficiently perform the solid-phase polymerization.

[0056] When the polyester resin composition of the present invention is processed into various products, one or more of various additives, for example, colorants including pigments and dyes, lubricants, antistatic agents, flame retardants, ultraviolet absorbers, antibacterial agents, nucleating agents, plasticizers, release agents, antioxidants, and the like, may be added within a range that does not impair the effects of the present invention.

[0057] Specific examples of the method for producing the polyester resin composition of the present invention will be given below, but the present invention is not limited thereto. A slurry of terephthalic acid and ethylene glycol (1.15 times the molar amount of terephthalic acid) is gradually added to an esterification reactor containing dissolved bishydroxyethyl terephthalate (BHT) at 250°C to allow the esterification reaction to proceed. The temperature in the reaction system is controlled to be 245-250°C, and the esterification reaction is terminated when the reaction rate reaches 95%.

[0058] The esterification product thus obtained at 255°C is transferred to a polymerization apparatus, and a manganese compound, an organogermanium compound having a Ge-C bond and a Ge-O bond are added. Then, phosphoric acid is added. During these operations, it is preferable to keep the temperature in the system at 240 to 255°C so that the esterification product does not solidify.

[0059] Thereafter, the temperature inside the polymerization apparatus is gradually raised to 290° C., while the pressure inside the polymerization apparatus is gradually reduced from normal pressure to 133 Pa or less to distill off ethylene glycol. The reaction is terminated when a predetermined stirring torque is reached, the pressure inside the reaction system is returned to normal pressure with nitrogen gas, and the molten polyester is discharged into cold water in the form of strands and cut to obtain a polyester resin composition.

[0060] The method for producing the film is described below, but is not limited thereto. The polyester resin composition obtained by the above method is vacuum dried at 180°C for 3 hours and fed to an extruder under a nitrogen atmosphere. It is extruded from a T-die at an extrusion temperature of 280°C, quenched on a casting drum (20°C), and sheeted by an electrostatic application method. This sheet is stretched at a longitudinal stretching temperature of 90°C, a longitudinal stretching ratio of 3.6 times, a transverse stretching temperature of 110°C, and a transverse stretching ratio of 3.6 times, and heat-treated at 210°C for 3 seconds to obtain a film with a thickness of about 40 μm.

[0061] The polyester resin composition of the present invention generates little catalyst-derived foreign matter during melt molding or processing, and can therefore be suitably used for various applications such as films, fibers, bottles, and injection molded products, and can be particularly used for high-quality films such as optical films and release films.

[0062] The film may be a single film made of the polyester resin composition of the present invention, or a laminate film having at least one layer of the polyester resin composition of the present invention. EXAMPLES

[0063] The present invention will be described in more detail below with reference to examples. The physical properties in the examples were measured by the following methods. The methods described below are for the single component polyester resin composition of the present invention. However, in the case of a molded product made of multiple resins such as a laminated film, the resins of each layer are isolated by, for example, scraping, and then analyzed.

[0064] (1) Determination of germanium in polyester resin composition (unit: mass ppm) Take 5 g of the sample in a platinum dish, melt and carbonize it with an electric heater, and then completely ash it in an electric furnace (700 °C) over 1.5 hours. Next, dissolve the ash in 5 mL of concentrated hydrochloric acid, add pure water to make a 10% hydrochloric acid aqueous solution, and use it as the measurement sample. Using the above solution as the measurement sample, quantification was performed by atomic absorption spectrometry (flame: acetylene-nitrous oxide). Note that an atomic absorption spectrophotometer "ZA-3300" manufactured by Hitachi High-Tech Science Corporation was used.

[0065] (2) Quantification of phosphorus element in the polyester resin composition (unit: mass ppm) The polyester resin composition was molded into a cylindrical shape with a melt press machine and measured using a fluorescence X-ray analyzer (model number: 3270) manufactured by Rigaku Corporation.

[0066] (3) Color tone of the polyester resin composition The polyester resin composition chips were measured and judged as Hunter value (b value) using a color difference meter (SM Color Computer model SM-T45 manufactured by Suga Test Instruments Co., Ltd.). The smaller this value, the less yellowing and the better the color tone. Judgment was made according to the following criteria, and × was regarded as unqualified. ◎: 0 ≤ b value ≤ 5 〇: 5 < b value ≤ 8 △: 8 < b value ≤ 10 ×: 10 < b value

[0067] (4) Foreign matter evaluation in the polyester resin composition Take 0.1 mg of the polyester resin composition and sandwich it between two cover glasses on a hot plate heated to 290 °C to melt it and create a prepared slide on which a polymer thin film is formed. Observe this prepared slide with an optical microscope (manufactured by Olympus Corporation: BX53-FL, 400 times magnification, bright field), and count all observable foreign matter defects. Then, irradiate with fluorescence and observe at the same magnification, and count the observed light spots. The light spots observed with the fluorescence microscope are derived from gels, and the number of particulate matters derived from the catalyst was obtained by subtracting the number of foreign matters observed with the optical microscope. Judgment was made as follows based on the number, and × was regarded as unqualified. ◎: 0 - 2 pieces / 0.1 mg 〇: 3 - 5 pieces / 0.1 mg △:6~8 pieces / 0.1mg ×: 9 or more pieces / 0.1 mg.

[0068] (5) Evaluation of internal foreign matter in film The obtained polyester resin composition was vacuum dried at 180°C for 3 hours and fed to an extruder under a nitrogen atmosphere. It was discharged from a T-die at an extrusion temperature of 280°C, quenched on a casting drum (20°C), and sheeted by an electrostatic application method. This sheet was stretched at a longitudinal stretching temperature of 90°C, a longitudinal stretching ratio of 3.6 times, a transverse stretching temperature of 110°C, and a transverse stretching ratio of 3.6 times, and heat-treated at 210°C for 3 seconds to obtain a film with a thickness of about 40 μm.

[0069] A 10cm square marking was made on this film sample, and 10 random locations within the marking were measured using a polarizing microscope at 50x magnification to measure the size of the core of the foreign matter defect, where the film around the foreign matter appears iridescent and distorted in polarized light, and the number of particles with a long diameter of 1μm or more was counted. The marked area was then confirmed using a fluorescent microscope, and the light spots were deemed to be internal foreign matter, with the average number of particles calculated and a judgment made based on this number. The internal foreign matter was mainly polymer degradation (gel, etc.), and an "X" was deemed a failure. ◎:0~15 pieces / mm 2 〇:16~20 pieces / mm 2 △:21~30 pieces / mm 2 ×: 31 or more pieces / mm 2 .

[0070] Furthermore, foreign matter defects that do not glow under a fluorescent microscope are mainly foreign matter derived from the catalyst. It is possible to identify the metal type of the foreign matter by performing elemental analysis of the catalyst-derived foreign matter using SEM-EDX.

[0071] Example 1 A slurry consisting of 86 parts by weight of terephthalic acid and 37 parts by weight of ethylene glycol (1.15 times the molar amount relative to terephthalic acid) was gradually added to an esterification reactor charged with 105 parts by weight of bishydroxyethyl terephthalate (hereinafter referred to as BHT) melted at 250°C, and the esterification reaction was allowed to proceed. The temperature in the reaction system was controlled to be 245 to 250°C, and the esterification reaction was terminated when the reaction rate calculated from the amount of water distilled reached 95%.

[0072] 105 parts by weight (corresponding to 100 parts by weight of PET) of BHT was charged in a molten state from the esterification reactor into the polymerization apparatus, and the temperature was set to 255°C. An ethylene glycol solution of manganese acetate tetrahydrate (23 ppm by mass as manganese element relative to the weight of the polyester resin composition) and bis[2-carboxyethylgermanium(IV)]sesquioxide (45 ppm by mass as germanium element relative to the weight of the polyester resin composition) were added. Then, an ethylene glycol solution of phosphoric acid (38 ppm by mass as phosphorus element relative to the weight of the polyester resin composition) was added. For the bis[2-carboxyethylgermanium(IV)]sesquioxide, an ethylene glycol solution was used in which 1 part by weight of bis[2-carboxyethylgermanium(IV)]sesquioxide was completely dissolved in 3.75 parts by weight of a 20% aqueous solution of tetraethylammonium hydroxide, and then ethylene glycol was added.

[0073] Thereafter, the temperature in the polymerization apparatus was gradually increased to 290°C, and the pressure was reduced from normal pressure to 133 Pa or less, and the polymerization reaction was carried out until a predetermined stirring torque was observed at 290°C. After the polymerization reaction was completed, the reaction system was returned to normal pressure with nitrogen gas, and the molten polyester in the polymerization apparatus was discharged in the form of strands into a water tank, cooled, and then cut to obtain a polyester resin composition in the form of pellets. The properties of the obtained polyester resin composition are shown in Table 1.

[0074] The polyester resin composition obtained in Example 1 had little foreign matter, a good color tone, and physical properties suitable for a release film.

[0075] (Examples 2 to 8) A polyester resin composition was obtained in the same manner as in Example 1, except that the amount of the germanium compound added was changed so that the germanium element content was as shown in Table 1. The properties of the obtained polyester resin composition are shown in Table 1.

[0076] In the polyester resin composition obtained in Example 2, the amount of germanium compound added was relatively small, and therefore the polymerization time was somewhat long, resulting in a slight increase in the amount of internal foreign matter in the film and a slight deterioration in color tone.

[0077] The polyester resin compositions obtained in Examples 3 and 4 had little foreign matter, good color tone, and physical properties suitable for a release film.

[0078] The polyester resin composition obtained in Example 5 had little foreign matter, but the color tone was slightly deteriorated.

[0079] The polyester resin composition obtained in Example 6 had a relatively large amount of germanium compound added, and therefore tended to have a slightly deteriorated heat resistance, resulting in the generation of foreign matter and a deterioration in color tone.

[0080] In the polyester resin composition obtained in Example 7, the amount of germanium compound added was small, so the polymerization time was long, and the amount of internal foreign matter generated in the film and the color tone were somewhat deteriorated.

[0081] The polyester resin composition obtained in Example 8 had a large amount of germanium compound added, and thus the amount of foreign matter generated increased and the color tone deteriorated slightly.

[0082] [Table 1]

[0083] (Examples 9 and 10) A polyester resin composition was obtained in the same manner as in Example 1, except that the type of phosphorus compound was changed as shown in Table 2. The properties of the obtained polyester resin composition are shown in Table 2. The polyester resin compositions obtained in Examples 9 and 10 had little foreign matter, good color tone, and physical properties suitable for release films.

[0084] (Examples 11 and 12) A polyester resin composition was obtained in the same manner as in Example 1, except that the type of germanium compound was changed as shown in Table 2. The properties of the obtained polyester resin composition are shown in Table 2. The polyester resin compositions obtained in Examples 11 and 12 had little foreign matter, good color tone, and physical properties suitable for release films.

[0085] Comparative Example 1 A polyester resin composition was obtained in the same manner as in Example 1, except that an ethylene glycol solution of tetra-n-butoxytitanium (10 ppm by mass as titanium element relative to the weight of the polyester resin composition) was added instead of bis[2-carboxyethylgermanium(IV)]sesquioxide. The properties of the obtained polyester resin composition are shown in Table 2. The polyester resin composition obtained in Comparative Example 1 generated a large amount of foreign matter, and the chips were strongly yellowed, so that it was unacceptable.

[0086] Comparative Example 2 A polyester resin composition was obtained in the same manner as in Example 1, except that an ethylene glycol slurry of diantimony trioxide (70 ppm by mass as antimony element relative to the weight of the polyester resin composition) was added instead of bis[2-carboxyethylgermanium(IV)]sesquioxide. The properties of the obtained polyester resin composition are shown in Table 2. The polyester resin composition obtained in Comparative Example 2 was unacceptable because it generated a large amount of foreign matter due to the addition of an antimony compound that is easily converted into foreign matter.

[0087] (Comparative Examples 3 to 6) A polyester resin composition was obtained in the same manner as in Example 1, except that bis[2-carboxyethylgermanium(IV)]sesquioxide was replaced with another germanium compound as shown in Table 2. The properties of the obtained polyester resin composition are shown in Table 2.

[0088] The polyester resin composition obtained in Comparative Example 3 required a longer polymerization time due to the low solubility of the germanium catalyst solution, and was prone to precipitation and generation of foreign matter due to the low solubility of the germanium catalyst solution, and therefore failed.

[0089] The polyester resin compositions obtained in Comparative Examples 4 to 6 generated a large amount of foreign matter and had a slightly yellowish color, and were therefore unacceptable.

[0090] [Table 2]

[0091] (Examples 13 to 21) A polyester resin composition was obtained in the same manner as in Example 1, except that the amount of phosphoric acid added was changed so that the phosphorus element content was as shown in Table 3. The properties of the obtained polyester resin composition are shown in Table 3.

[0092] The polyester resin composition obtained in Example 13 generated a small amount of foreign matter, but because the amount of phosphoric acid added was relatively small, the heat resistance was slightly poor, and the chips turned yellow and the amount of foreign matter inside the film increased.

[0093] The polyester resin compositions obtained in Examples 14 to 17 had low amounts of foreign matter generated, good color tones, and other physical properties suitable for release films.

[0094] The polyester resin composition obtained in Example 18 generated a small amount of foreign matter, but had a slightly long polymerization time due to the relatively large amount of phosphoric acid added, and was slightly yellowish.

[0095] The polyester resin composition obtained in Example 19 had a relatively large amount of phosphoric acid added, and therefore the polymerization time was long, so it had a slight yellowish tinge and the amount of internal foreign matter in the film increased slightly.

[0096] The polyester resin composition obtained in Example 20 had a small amount of phosphoric acid added, which resulted in poor heat resistance, an increase in foreign matter, and a slight deterioration in color tone.

[0097] The polyester resin composition obtained in Example 21 had a long polymerization time due to the large amount of phosphoric acid added, and was somewhat yellowish and had an increased amount of foreign matter.

[0098] [Table 3]

Claims

1. A polyester resin composition comprising an organogermanium compound having a Ge-C bond and a Ge-O bond.

2. 2. The polyester resin composition according to claim 1, wherein the organogermanium compound has the structure shown below. 【Chemistry 1】 R １ is a functional group bonded to a Ge element via a C element, and may include an alkyl group, a carboxyl group, a hydroxyl group, or an alkoxy group. ２ is a functional group bonded to an O element via an element selected from a C element, a Ge element, an O element, and an H element.

3. 2. The polyester resin composition according to claim 1, wherein the organogermanium compound has the structure shown below. 【Chemistry 2】 R ３ , R ４ is a functional group bonded to a Ge element via a C element, and may include an alkyl group, a carboxyl group, a hydroxyl group, or an alkoxy group.

4. 2. The polyester resin composition according to claim 1, wherein the content of germanium element in the polyester resin composition is 3 ppm by mass or more and 100 ppm by mass or less.

5. 2. The polyester resin composition according to claim 1, wherein the content of phosphorus element is 5 ppm by mass or more and 200 ppm by mass or less based on the polyester resin composition.

6. 2. The polyester resin composition according to claim 1, wherein the organogermanium compound is bis[2-carboxyethylgermanium(IV)]sesquioxide.

7. 2. The polyester resin composition according to claim 1, wherein the polyester is polyethylene terephthalate.

8. A polyester film comprising the polyester resin composition of claim 1.

9. A release polyester film comprising the polyester resin composition of claim 1.

10. A release film comprising the polyester resin composition of claim 1 which is used as a film for a dry film resist support.

11. A method for producing a polyester resin composition, comprising carrying out an esterification reaction between a dicarboxylic acid component and a diol component, or an ester exchange reaction between a dicarboxylic acid ester-forming derivative component and a diol component, followed by a polycondensation reaction to produce a polyester, and adding an organogermanium compound having a Ge-C bond and a Ge-O bond at a stage when the IV (intrinsic viscosity) of the polyester is 0.4 or less.

12. The method for producing a polyester resin composition according to claim 11, wherein the organogermanium compound has a structure represented by the formula (1). 【Chemistry 3】

13. The method for producing a polyester resin composition according to claim 11, wherein the organogermanium compound has a structure represented by the formula (2). 【Chemistry 4】

14. The method for producing a polyester resin composition according to claim 11, wherein the content of germanium element in the polyester resin composition is 3 ppm by mass or more and 100 ppm by mass or less.

15. The method for producing a polyester resin composition according to claim 11, wherein the content of phosphorus element in the polyester resin composition is 5 ppm by mass or more and 200 ppm by mass or less.

16. The method for producing a polyester resin composition according to claim 11, wherein the organogermanium compound is bis[2-carboxyethylgermanium(IV)]sesquioxide.

17. The method for producing a polyester resin composition according to claim 11, wherein the polyester is polyethylene terephthalate.

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