Method for producing polyester resin composition

Abstract

To provide a method for producing a polyester resin composition that exhibits improved resistance to a decrease in intrinsic viscosity and also demonstrates reduced appearance defects in molded products.SOLUTION: A method for producing a polyester resin composition includes the steps for melt-kneading components (A), (B), and (C-1), wherein the ratio of the number of epoxy groups in component (B) to the number of hydroxyl groups in component (C-1) employed in the step is from 1:0.03 to 1:0.28. (A) Polyester resin. (B) Epoxy group-containing acrylic polymer. (C-1) Monohydric alcohol.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Polyester resins such as polyethylene terephthalate (PET) and glycol-modified polyethylene terephthalate (PETG) are used in our daily lives because of their excellent strength, transparency and processability, for example, in food containers such as PET bottles and fiber materials such as fleece. In industry, they are also used for tapes and films, and when made into glass fiber reinforced resins, they are used in electrical and electronic parts and automotive parts.

[0003] Polyester resins undergo high temperature conditions throughout all steps of their life cycle, including the synthesis process, the subsequent extrusion steps and thermoforming, blow molding or injection molding in the molten state, as well as the compounding and recycling processes.

[0004] Under such high temperature conditions, especially during compounding and recycling processes, the molecular weight of the polyester resin is degraded by hydrolysis, which affects the mechanical, thermal and rheological properties of the polyester resin composition, such as a decrease in the intrinsic viscosity (IV value) of the polyester resin composition.

[0005] PET bottles are required to have the highest IV value among molded products of polyester resin compositions, but most of the recycled PET bottles are used for films and other low-cost applications because the IV value decreases during the recycling process, etc. Therefore, if the decrease in the IV value of polyester resin compositions can be improved, it is possible to expand the applications of recycled polyester resin compositions, for example.

[0006] A known conventional technique for improving the IV value reduction of polyester resin compositions is to use a crosslinking agent called a "chain extender" as a processing aid when melt processing polyester resins. Chain extenders usually have two or more functional groups, which crosslink and "recombine" chain fragments generated by depolymerization of polyester resins, thereby suppressing the reduction in molecular weight of the polyester resin and improving the IV value reduction.

[0007] As the chain extender, for example, as disclosed in Patent Document 1, carboxyl group reactive end blocking agents such as epoxy compounds, oxazoline compounds, oxazine compounds, carbodiimide compounds, and isocyanate compounds have been used (paragraph

[0009] ). However, it is known that depending on the processing conditions of the polyester resin composition, the chain extender decomposes, and foaming occurs due to the generated gas, causing poor appearance of polyester resin composition molded products such as films.

[0008] In addition, chain extenders having epoxy groups as functional groups are very reactive, and in the case of polyethylene terephthalate, where the processing temperature is in a high temperature environment of 240 to 300°C, the chain extender supplied to the extruder may start to react before being adequately dispersed. This causes the reaction to proceed unevenly, resulting in local crosslinking, which may lead to surface roughness in molded products of the polyester resin composition or defects known as "lumps" in which the crosslinked product looks like a foreign object.

[0009] As a conventional technique for improving local crosslinking caused by such chain extenders, for example, Patent Document 2 reports a resin composition using an acrylonitrile-butadiene-styrene copolymer or polycarbonate as a carrier resin in order to improve the dispersibility of the chain extender (paragraph

[0023] ).

[0010] However, this technique uses a non-reactive resin different from polyester resin as a carrier resin, and therefore has a large effect on the composition of the polyester resin composition, so that the applications of the polyester resin composition obtained by this technique are limited. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] JP 2008-150598 A [Patent Document 2] Special Publication No. 2017-532427 Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a method for producing a polyester resin composition which improves the decrease in intrinsic viscosity of the polyester resin composition and improves the appearance defects of molded articles produced from the composition. [Means for solving the problem]

[0013] As a result of intensive research to solve the above problems, the present inventors have found that, in the production of a polyester resin composition, unnecessary crosslinking caused by a chain extender can be suppressed by adding a monohydric or dihydric alcohol, or an aliphatic carboxylic acid or an aliphatic dicarboxylic acid, thereby solving the above problems. Based on these findings, the present inventors have further researched and completed the present invention.

[0014] That is, the present invention comprises the following (1) to (4). (1) A method for producing a polyester resin composition, comprising the step of heating and kneading the following components (A), (B) and (C-1), wherein the ratio of the number of epoxy groups in component (B) to the number of hydroxyl groups in component (C-1) [(B):(C-1)] used in said step is 1:0.03 to 1:0.28: (A) Polyester resin (B) Epoxy group-containing acrylic polymer (C-1) Monohydric alcohol (2) A method for producing a polyester resin composition, comprising the step of heating and kneading the following components (A), (B) and (D-1), wherein the ratio of the number of epoxy groups in component (B) to the number of carboxy groups in component (D-1) used in said step [(B):(D-1)] is 1:0.03 to 1:0.28. (A) Polyester resin (B) Epoxy group-containing acrylic polymer (D-1) Aliphatic carboxylic acid (3) A method for producing a polyester resin composition, comprising the step of heating and kneading the following components (A), (B) and (C-2), wherein the ratio of the number of epoxy groups in component (B) used in said step to the number of hydroxyl groups in component (C-2) [(B):(C-2)] is 1:0.15 to 1:1.1: (A) Polyester resin (B) Epoxy group-containing acrylic polymer (C-2) Dihydric alcohol having a number average molecular weight of 800 or more (4) A method for producing a polyester resin composition, comprising the step of heating and kneading the following components (A), (B) and (D-2), wherein the ratio of the number of epoxy groups in component (B) to the number of carboxy groups in component (D-2) used in said step [(B):(D-2)] is 1:0.15 to 1:1.1. (A) Polyester resin (B) Epoxy group-containing acrylic polymer (D-2) Aliphatic dicarboxylic acid having a number average molecular weight of 800 or more Effect of the Invention

[0015] According to the method for producing a polyester resin composition of the present invention, the decrease in the intrinsic viscosity of the polyester resin composition is improved, and the appearance defects of the molded products thereof are improved. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [(A) Polyester resin] The polyester resin used as component (A) in the present invention is not particularly limited, and any polymer made of diol, dicarboxylic acid, and hydroxycarboxylic acid can be used. Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, neopentyl glycol, and 1,4-cyclohexanedimethanol. Examples of dicarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, malonic acid, maleic acid, fumaric acid, succinic acid, adipic acid, and sebacic acid. Examples of hydroxycarboxylic acids include lactic acid, glycolic acid, citric acid, malic acid, tartaric acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, 4-hydroxycyclohexanecarboxylic acid, and the like. Examples of cyclic condensates include ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolide, lactide, and the like.

[0017] Examples of polyester resins suitable for use in the present invention include polyethylene terephthalate (PET), polyethylene succinate, polybutylene terephthalate, polybutylene succinate, polycaprolactone, poly-L-lactic acid, and polyglycolic acid. The polyester resin may be not only a homopolymer of a single monomer, but also a copolymer in which a monomer that exhibits the desired physical properties and characteristics is used in combination. Examples of such resins include glycol-modified polyethylene terephthalate (PETG), such as a copolymer of terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol. Among these polyester resins, PET and PETG are preferred from the viewpoints of processability and cost. These polyester resins may be used alone or in any combination of two or more.

[0018] [(B) Epoxy group-containing acrylic polymer] The epoxy group-containing acrylic polymer used as component (B) in the present invention is not particularly limited as long as it is a chain extender having epoxy groups as crosslinking points, which is used in the production of polyester resin compositions.

[0019] Examples of such component (B) include glycidyl ether compounds such as polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, and polypropylene glycol diglycidyl ether, and glycidyl esters such as methyl methacrylate-glycidyl methacrylate-styrene copolymer, etc. Among these components (B), methyl methacrylate-glycidyl methacrylate-styrene copolymer is preferred from the viewpoint of reaction stability.

[0020] Examples of component (B) that can be commercially manufactured and sold include Joncryl ADR-4300 and Joncryl ADR-4468 (product names: methyl methacrylate-glycidyl methacrylate-styrene copolymer; manufactured by BASF), and these can be used in the present invention.

[0021] [(C-1) Monohydric alcohol] Examples of monohydric alcohols used as component (C-1) in the present invention include methanol, ethanol, n-propanol, isopropanol, n-butanol, amyl alcohol, benzyl alcohol, cyclohexanol, diacetone alcohol, isobutanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, isostearyl alcohol, cetostearyl alcohol, oleyl alcohol, etc. Among these components (C-1), myristyl alcohol and stearyl alcohol are preferred from the viewpoint of processing stability in the heat-kneading step.

[0022] [(D-1) Aliphatic carboxylic acid] The aliphatic carboxylic acid used as component (D-1) in the present invention may be any compound having an aliphatic chain and a carboxylic acid structure, and may be, for example, a saturated fatty acid or an unsaturated fatty acid. The aliphatic chain of component (D-1) may be linear or branched. The number of carbon atoms constituting component (D-1) is preferably 8 to 30, more preferably 10 to 22. The molecular weight of component (D-1) is preferably 144 to 452, more preferably 172 to 340.

[0023] Examples of the component (D-1) include butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, 2-hexyldecanoic acid, palmitoleic acid, margaric acid, stearic acid, 2-octyldecanoic acid, 2-(4-methylhexyl)-8-methyldecanoic acid, 2-(4,4-dimethylpentan-2-yl)-5,7 ,7-trimethyloctanoic acid, 12-hydroxystearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15)-linolenic acid, (6,9,12)-linolenic acid, eleostearic acid, arachidic acid, 2-(6-methylpentan-2-yl)-5,9-dimethyldecanoic acid, arachidonic acid, behenic acid, lignoceric acid, nervonic acid, cerotic acid, montanic acid, melissic acid, etc. Among these, palmitic acid, stearic acid, and lauric acid are preferred, and stearic acid is particularly preferred, from the viewpoint of processing stability in the heating and kneading step.

[0024] [(C-2) Dihydric alcohol having a number average molecular weight of 800 or more] Examples of the dihydric alcohol having a number average molecular weight of 800 or more used as component (C-2) in the present invention include polyethylene glycol having a number average molecular weight of 800 or more, and polypropylene glycol having a number average molecular weight of 800 or more. Among these components (C-2), polyethylene glycol having a number average molecular weight of 800 or more is preferred from the viewpoint of stabilizing the crosslinked structure formed by the reaction of the hydroxyl group of component (C-2) with the epoxy group of component (B) in the heating and kneading step. There is no particular upper limit to the number average molecular weight of component (C-2), but it can be, for example, 20,000.

[0025] In this specification, the number average molecular weight is defined as a polystyrene-equivalent number average molecular weight determined by size exclusion chromatography (SEC) using tetrahydrofuran (THF) as a solvent.

[0026] [(D-2) Aliphatic dicarboxylic acid having a number average molecular weight of 800 or more] The aliphatic dicarboxylic acid having a number average molecular weight of 800 or more used as component (D-2) in the present invention may be a compound having an aliphatic chain and a dicarboxylic acid structure, and may be, for example, a saturated fatty acid or an unsaturated fatty acid, as long as it has a number average molecular weight of 800 or more. In addition, the aliphatic chain of component (D-2) may be linear or branched. There is no particular limit to the upper limit of the number average molecular weight of component (D-2), but it may be, for example, 20,000.

[0027] Examples of the component (D-2) include polyethylene glycol derivatives (PEG derivatives) in which the hydroxyl groups at both ends of polyethylene glycol are substituted with carboxyl groups and have a number average molecular weight of 800 or more.

[0028] In the method for producing the polyester resin composition of the present invention, the above-mentioned components (A) and (B) and (C-1), (D-1), (C-2) or (D-2) are used to carry out any one of the following methods 1 to 4.

[0029] [Method 1] In the process of heating and kneading the components (A), (B) and (C-1), the amounts of the components (B) and (C-1) are adjusted so that the ratio of the number of epoxy groups in the component (B) to the number of hydroxyl groups in the component (C-1) [(B):(C-1)] is 1:0.03 to 1:0.28 (preferably 1:0.05 to 1:0.25). By setting the ratio in this range, the hydroxyl groups in the component (C-1) react with the epoxy groups in the component (B), and the number of epoxy groups in the component (B) that react with the component (A) is appropriately reduced. As a result, the reaction between the components (A) and (B) becomes gentle, which can suppress unnecessary crosslinking by the component (B) that functions as a chain extender, and it is believed that the appearance defect of the molded product of the polyester resin composition is improved.

[0030] Here, the number of hydroxyl groups H of component (C-1) per epoxy group of component (B) is E can be calculated according to the following formula (1) from the charged amounts of components (B) and (C-1), the epoxy group equivalent (molecular weight per epoxy group) of component (B), and the hydroxyl group equivalent (molecular weight per hydroxyl group) of component (C-1). H E =(W C-1 / E C-1 ) / (W B / E B ) · · · (1) W B : Amount of component (B) [g] W C-1 : Amount of ingredient (C-1) [g] E B : Epoxy group equivalent of component (B) [g / eq] E C-1 : Hydroxyl equivalent of component (C-1) [g / eq]

[0031] In Method 1, more specifically, a method in which components (A), (B), and (C-1) are simultaneously heated and kneaded, or a method in which components (B) and (C-1) are heated and kneaded and then added to molten component (A) and heated and kneaded, can be carried out.

[0032] [Method 2] In the process of heating and kneading the components (A), (B) and (D-1), the amounts of the components (B) and (D-1) are adjusted so that the ratio of the number of epoxy groups in the component (B) to the number of carboxy groups in the component (D-1) [(B):(D-1)] is 1:0.03 to 1:0.28 (preferably 1:0.05 to 1:0.25). By setting the ratio in this range, the carboxy groups in the component (D-1) react with the epoxy groups in the component (B), and the number of epoxy groups in the component (B) that react with the component (A) is appropriately reduced. As a result, the reaction between the components (A) and (B) becomes gentle, which can suppress unnecessary crosslinking by the component (B) that functions as a chain extender, and it is believed that the appearance defect of the molded product of the polyester resin composition is improved.

[0033] Here, the number of carboxy groups in component (D-1) per epoxy group in component (B) is C E can be calculated according to the following formula (2) from the charged amounts of components (B) and (D-1), the epoxy group equivalent (molecular weight per epoxy group) of component (B), and the carboxy group equivalent (molecular weight per carboxy group) of component (D-1). C E =(W D-1 / E D-1 ) / (W B / E B ) · · · (2) W B : Amount of component (B) [g] W D-1 : Amount of ingredient (D-1) [g] E B : Epoxy group equivalent of component (B) [g / eq] E D-1 : Carboxy group equivalent of component (D-1) [g / eq]

[0034] In Method 2, more specifically, a method in which components (A), (B) and (D-1) are simultaneously heated and kneaded, or a method in which components (B) and (D-1) are heated and kneaded and then added to molten component (A) and heated and kneaded, can be carried out.

[0035] [Method 3] In the process of heating and kneading the components (A), (B) and (C-2), the amounts of the components (B) and (C-2) are adjusted so that the ratio of the number of epoxy groups in the component (B) to the number of hydroxyl groups in the component (C-2) [(B):(C-2)] is 1:0.15 to 1:1.1 (preferably 1:0.2 to 1:1). By setting the ratio in this range, the hydroxyl groups in the component (C-2) react with the epoxy groups in the component (B), and the number of epoxy groups in the component (B) that react with the component (A) is appropriately reduced. As a result, the reaction between the components (A) and (B) becomes gentle, which can suppress unnecessary crosslinking caused by the component (B) that functions as a chain extender, and it is believed that the appearance defect of the molded product of the polyester resin composition is improved.

[0036] Here, the number of hydroxyl groups H of component (C-2) per epoxy group of component (B) is E can be calculated according to the following formula (3) from the charged amounts of components (B) and (C-2), the epoxy group equivalent (molecular weight per epoxy group) of component (B), and the hydroxyl group equivalent (molecular weight per hydroxyl group) of component (C-2). H E =(W C-2 / E C-2 ) / (W B / E B ) · · · (3) W B : Amount of component (B) [g] W C-2 : Amount of ingredient (C-2) [g] E B : Epoxy group equivalent of component (B) [g / eq] E C-2 : Hydroxyl equivalent of component (C-2) [g / eq]

[0037] In Method 3, more specifically, a method in which components (A), (B), and (C-2) are simultaneously heated and kneaded, or a method in which components (B) and (C-1) are heated and kneaded and then added to molten component (A) and heated and kneaded, can be carried out.

[0038] [Method 4] In the process of heating and kneading the components (A), (B) and (D-2), the amounts of the components (B) and (D-2) are adjusted so that the ratio of the number of epoxy groups in the component (B) to the number of carboxy groups in the component (D-2) [(B):(D-2)] is 1:0.15 to 1:1.1 (preferably 1:0.2 to 1:1). By setting the ratio in this range, the carboxy groups in the component (D-2) react with the epoxy groups in the component (B), and the number of epoxy groups in the component (B) that react with the component (A) is appropriately reduced. As a result, the reaction between the components (A) and (B) becomes gentle, which can suppress unnecessary crosslinking by the component (B) that functions as a chain extender, and it is believed that the appearance defect of the molded product of the polyester resin composition is improved.

[0039] Here, the number of carboxyl groups in component (D-2) per epoxy group in component (B) is C E can be calculated according to the following formula (4) from the charged amounts of components (B) and (D-2), the epoxy group equivalent (molecular weight per epoxy group) of component (B), and the carboxy group equivalent (molecular weight per carboxy group) of component (D-2). C E =(W D-2 / E D-2 ) / (W B / E B ) · · · (4) W B : Amount of component (B) [g] W D-2 : Amount of ingredient (D-2) [g] E B : Epoxy group equivalent of component (B) [g / eq] E D-2 : Carboxylic group equivalent of component (D-2) [g / eq]

[0040] In Method 4, more specifically, a method in which components (A), (B) and (D-2) are simultaneously heated and kneaded, or a method in which components (B) and (D-1) are heated and kneaded and then added to molten component (A) and heated and kneaded, can be carried out.

[0041] The method for producing the polyester resin composition of the present invention is not particularly limited except for carrying out the above-mentioned methods 1 to 4, and can be carried out according to a known method.

[0042] For example, from the viewpoint of facilitating molding into films, sheets, etc., a preferred method is to process the polyester resin composition obtained by heating and kneading the above-mentioned components according to the conditions of the above-mentioned methods 1 to 4 into a masterbatch, and then blend the masterbatch with a polyester resin to produce the polyester resin composition.

[0043] When the master batch is prepared according to the conditions of the above method 1, the total amount of the components (B) and (C-1) added to 100 parts by mass of the component (A) is 9 to 15 parts by mass, preferably 10 to 14 parts by mass. When the master batch is prepared according to the conditions of the above method 2, the total amount of the components (B) and (D-1) added to 100 parts by mass of the component (A) is 9 to 16 parts by mass, preferably 10 to 15 parts by mass. When the master batch is prepared according to the conditions of the above method 3, the total amount of the components (B) and (C-2) added to 100 parts by mass of the component (A) is 14 to 70 parts by mass, preferably 15 to 60 parts by mass. When the master batch is prepared according to the conditions of the above method 4, the total amount of the components (B) and (D-2) added to 100 parts by mass of the component (A) is 10 to 16 parts by mass, preferably 9 to 15 parts by mass.

[0044] As the kneader used in the heat kneading step, for example, a Banbury mixer, a kneader, a single screw extruder, a twin screw extruder, etc. can be used. Among them, in consideration of productivity, kneading power, etc., a twin screw extruder is preferable. Twin screw extruders include twin screw counter-rotating non-intermeshing extruders, twin screw counter-rotating intermeshing extruders, twin screw co-rotating non-intermeshing extruders, twin screw co-rotating intermeshing extruders, etc., and any of them can be used, but it is preferable to use a twin screw co-rotating intermeshing extruder from the viewpoint of kneading power and productivity.

[0045] The heating temperature in the heat-kneading step may be equal to or higher than the temperature at which component (A) melts and within a range in which component (A) and other components do not deteriorate excessively, for example, 200 to 290° C. The heat-kneading time varies depending on the kneader used, heating conditions, etc., but is, for example, 30 seconds to 10 minutes, and preferably 1 to 5 minutes, when a twin-screw extruder is used as the kneader.

[0046] The polyester resin composition obtained by the production method of the present invention may contain other substances that are usually used in polyester resins, as long as the effects of the present invention are not impaired. Examples of such additives include antistatic agents, antioxidants, neutralizing agents, nucleating agents, weather resistance agents, ultraviolet absorbers, and antiblocking agents.

[0047] The polyester resin composition obtained by the production method of the present invention is molded by a known molding method to obtain a molded product. For example, molded products by injection molding methods such as injection molding, injection blow molding, injection compression molding, and foam molding; molded products such as pipes and tubes, irregular shapes, electric wire coatings, multi-layer or single-layer films and sheets, monofilaments, multifilaments, and core-sheath fibers by extrusion molding methods such as T-die method, inflation method, and lamination; molded products by blow molding, vacuum molding, calendar molding, compression molding, and powder or granules by pulverization.

[0048] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. EXAMPLES

[0049] [Masterbatch production] (1) Raw materials 1) Component (A): Polyester resin 1-1) PETG (product name: SK2008; manufactured by SK Chemicals) 2) Component (B): Epoxy group-containing acrylic polymer 2-1) Methyl methacrylate-glycidyl methacrylate-styrene copolymer (product name: Joncryl ADR-4468; epoxy group equivalent: 310 g / eq; manufactured by BASF) 3) Component (C-1): Monohydric alcohol 3-1) Myristyl alcohol (hydroxyl equivalent: 214.4 g / eq; Nacalai Tesque) 3-2) Stearyl alcohol (hydroxyl equivalent weight 270.5 g / eq; Nacalai Tesque) 4) Component (D-1): Aliphatic carboxylic acid 4-1) Stearic acid (carboxy group equivalent: 284 g / eq; Wako Pure Chemical Industries, Ltd.) 4-2) Palmitic acid (carboxy group equivalent: 256 g / eq; Wako Pure Chemical Industries, Ltd.) 4-3) Lauric acid (carboxy group equivalent: 200 g / eq; Wako Pure Chemical Industries, Ltd.) 5) Component (C-2): Dihydric alcohol with a number average molecular weight of 800 or more 5-1) Polyethylene glycol 1 (trade name: PEG-1000; number average molecular weight 1000; hydroxyl equivalent 500 g / eq; manufactured by Toho Chemical Industry Co., Ltd.) 5-2) Polyethylene glycol 2 (trade name: PEG-1540; number average molecular weight 1540; hydroxyl equivalent 770 g / eq; manufactured by Toho Chemical Industry Co., Ltd.) 6) Component (D-2): Aliphatic dicarboxylic acid having a number average molecular weight of 800 or more 6-1) PEG derivative (Product name: Catalog No. SCHEM03431; Number average molecular weight 1000; Carboxy group equivalent 500g / eq; Manufactured by Shinsei Chemical Co., Ltd.) 7) Component (C-3): Dihydric alcohol having a number average molecular weight of less than 800 7-1) Polyethylene glycol 3 (trade name: PEG-500; number average molecular weight 500; hydroxyl equivalent 250 g / eq; manufactured by Toho Chemical Industry Co., Ltd.) 8) Component (C-4): Trihydric alcohol 8-1) Glycerin (hydroxyl equivalent: 30.7 g / eq; Fujifilm Wako Pure Chemical Industries, Ltd.) 9) Component (D-3): Aliphatic dicarboxylic acid having a number average molecular weight of less than 800 9-1) Adipic acid (number average molecular weight 146; carboxyl group equivalent 73 g / eq; Fujifilm Wako Pure Chemical Industries, Ltd.) 10) Component (D-4): Aliphatic tricarboxylic acid 10-1) Trimesic acid (carboxy group equivalent: 70 g / eq; manufactured by Tokyo Chemical Industry Co., Ltd.)

[0050] (2) Masterbatch compounding The formulations of the masterbatches prepared using the above raw materials are shown in Tables 1 to 11. These tables also show the ratio of the number of epoxy groups in component (B) to the number of hydroxyl groups in component (C-1) [(B):(C-1)], the ratio of the number of epoxy groups in component (B) to the number of carboxyl groups in component (D-1) [(B):(D-1)], the ratio of the number of epoxy groups in component (B) to the number of hydroxyl groups in component (C-2) [(B):(C-2)], and the ratio of the number of epoxy groups in component (B) to the number of carboxyl groups in component (D-2) [(B):(D-2)] (hereinafter, these ratios are referred to as "reaction point ratios").

[0051] [Table 1]

[0052] [Table 2]

[0053] [Table 3]

[0054] [Table 4]

[0055] [Table 5]

[0056] [Table 6]

[0057] [Table 7]

[0058] [Table 8]

[0059] [Table 9]

[0060] [Table 10]

[0061] [Table 11]

[0062] (3) Manufacturing method of master batch The raw materials shown in Tables 1 to 11 were weighed out so that the total amount was 1000 g, and were heated and kneaded using a twin-screw co-rotating intermeshing extruder (model: KZW15TW-45MG-NH; ​​screw diameter = 15; L / D = 45; manufactured by Technobel Co., Ltd.) at a barrel (C1 to C6, H / D) temperature of 180 to 200 ° C (C1 = 180 ° C; C2 to C6 = 200 ° C) and a screw rotation speed of 300 rpm, to extrude and mold a polyester resin composition. The polyester resin composition extruded in a strand shape was cut with a pelletizer to produce cylindrical (diameter 3 mm; length 3 mm) master batches (MB1 to 49). When all raw materials were solid, component (A) was fed into the main feeder of the extruder, and all raw materials other than component (A) were fed simultaneously into the side feeder of the extruder. In addition, when liquid raw materials were present, component (A) was fed into the main feeder of the extruder, component (B) was fed into the side feeder of the extruder, and the other raw materials were fed into the liquid addition line of the extruder.

[0063] [Preparation and evaluation of polyester resin film] (1) Raw materials 1) Component (A): Polyester resin 1-1) PET (product name: TRN-8550FF; IV value 0.77 g / dL; manufactured by Teijin Ltd.) 2) Master batches (MB1-49)

[0064] (2) Polyester resin film composition Tables 12 to 15 show the compositions of the polyester resin films produced using the above raw materials.

[0065] [Table 12]

[0066] [Table 13]

[0067] [Table 14]

[0068] [Table 15]

[0069] (3) Preparation of polyester resin film The raw materials shown in Tables 12 to 15 were kneaded in an amount 10 times that of the raw materials in Tables 12 to 15 in a single screw extruder (φ20 mm screw L / D=20; cylinder temperature: 280° C.), and polyester resin films 1 to 50 having a thickness of 50 μm were produced by the T-die method.

[0070] (4) Evaluation of film surface condition The surface state of the produced polyester resin films 1 to 50 was evaluated using a microscope under the following observation conditions. The results were coded according to the following evaluation criteria. The results are shown in Tables 16 and 17. <Observation conditions> Observation equipment: Microscope VHF-950F (Keyence) Lens: VH-Z100 Observation magnification: 300x

[0071] <Evaluation criteria> The film surface is smooth and not rough. The film surface is slightly rough and has some bumps: The film surface is slightly rough overall and has some bumps: △ The film surface is very rough overall, with many bumps visible: ×

[0072] (5) Measurement of intrinsic viscosity The intrinsic viscosity (IV value) of the prepared polyester resin films 1 to 49 was measured using an Ubbelohde viscometer in accordance with JIS K 7367-5. The solvent used was phenol / 1,1,2,2-tetrachloroethane = 60 / 40. The results are shown in Tables 16 and 17.

[0073] [Table 16]

[0074] [Table 17]

[0075] As is clear from the results of Tables 16 and 17, polyester resin films 1 to 24 obtained by the manufacturing methods of the examples of the present invention had film surface conditions of "○" or better, and also had higher IV values ​​than the control polyester resin film 50 produced using only component (A), and the decrease in IV value was improved. In contrast, polyester resin films 25 to 49 obtained by the manufacturing methods of the comparative examples had film surface conditions of "△" or worse, or had IV values ​​that were comparable to the control polyester resin film 50 produced using only component (A), and were inferior to those of the present invention.

Claims

1. A method for producing a polyester resin composition, comprising the step of heat-kneading the following components (A), (B), and (C-1), wherein the ratio of the number of epoxy groups in component (B) used in said step to the number of hydroxyl groups in component (C-1) [(B):(C-1)] is 1:0.03 to 1:0.28: (A) Polyester resin (B) Epoxy group-containing acrylic polymer (C-1) Monohydric alcohol

2. A method for producing a polyester resin composition, comprising a step of heating and kneading the following components (A), (B) and (D-1), wherein the ratio of the number of epoxy groups in component (B) used in said step to the number of carboxy groups in component (D-1) [(B):(D-1)] is 1:0.03 to 1:0.

28. (A) Polyester resin (B) Epoxy group-containing acrylic polymer (D-1) Aliphatic carboxylic acid

3. A method for producing a polyester resin composition, comprising the step of heat-kneading the following components (A), (B), and (C-2), wherein the ratio of the number of epoxy groups in component (B) used in said step to the number of hydroxyl groups in component (C-2) [(B):(C-2)] is 1:0.15 to 1:1.1: (A) Polyester resin (B) Epoxy group-containing acrylic polymer (C-2) Dihydric alcohol having a number average molecular weight of 800 or more

4. A method for producing a polyester resin composition, comprising the step of heat-kneading the following components (A), (B) and (D-2), wherein the ratio of the number of epoxy groups in component (B) used in said step to the number of carboxy groups in component (D-2) [(B):(D-2)] is 1:0.15 to 1:1.

1. (A) Polyester resin (B) Epoxy group-containing acrylic polymer (D-2) Aliphatic dicarboxylic acid having a number average molecular weight of 800 or more

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