Method for manufacturing 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] This 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 among the most familiar materials in our daily lives due to their excellent strength, transparency, and processability. For example, they are used in food containers, primarily PET bottles, and in textile materials such as fleece. In industrial applications, they are used in tapes and films, and when made into glass fiber reinforced resins, they are also used in electrical and electronic components and automotive parts.

[0003] Polyester resins undergo high-temperature conditions at every step of their lifecycle, including the synthesis process, subsequent extrusion steps and thermoforming, blow molding, or injection molding in a molten state, as well as compounding and recycling processes.

[0004] Under such high-temperature conditions, particularly during compounding and recycling processes, hydrolysis leads to a decrease in the molecular weight of the polyester resin, affecting the mechanical, thermal, and rheological properties of the polyester resin composition. For example, a decrease in the intrinsic viscosity (IV value), which indicates the viscosity of the polyester resin composition, occurs.

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

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

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

[0009] ). However, it has been found that depending on the processing conditions of the polyester resin composition, the chain extender may decompose, causing foaming due to the gas generated, resulting in defects in the appearance of molded polyester resin products such as films.

[0008] Furthermore, chain extenders that have epoxy groups as functional groups are highly reactive, and in high-temperature environments such as polyethylene terephthalate, where the processing temperature is 240-300°C, the chain extender supplied to the extruder may begin to react before it is properly dispersed. This can lead to an uneven reaction and localized crosslinking, resulting in surface roughness or defects called "bumps" in molded polyester resin compositions, where the crosslinked material appears as foreign matter.

[0009] As a conventional technique to improve localized crosslinking by such chain extenders, for example, Patent Document 2 reports a resin composition (paragraph

[0023] ) that uses acrylonitrile-butadiene-styrene copolymer or polycarbonate as a carrier resin to improve the dispersibility of the chain extender.

[0010] However, since this technique uses a non-reactive resin different from polyester resins as a carrier resin, it has a great influence on the composition of the polyester resin composition, and the applications of the polyester resin composition obtained by this technique have been limited.

Prior Art Document

Patent Document

[0011]

Patent Document 1

Patent Document 2

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, in which the decrease in intrinsic viscosity of the polyester resin composition is suppressed, and poor appearance of a molded article formed therefrom is improved.

Means for Solving the Problem

[0013] The inventors of the present invention have conducted intensive studies to solve the above problem, and as a result, found that in the production of a polyester resin composition, adding monohydric or dihydric alcohol, or aliphatic carboxylic acid or aliphatic dicarboxylic acid can suppress unnecessary crosslinking caused by a chain extender, and thus the above problem can be solved. The inventors of the present invention have conducted further studies based on these findings and have completed the present invention.

[0014] That is, the present invention consists of the following (1) to (4). (1) A method for producing a polyester resin composition, comprising a step of heat-kneading the following components (A), (B) and (C-1), wherein the ratio of the number of epoxy groups of component (B) to the number of hydroxyl groups of component (C-1) used in the step [(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 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 carboxyl groups in component (D-1) used in the 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) to the number of hydroxyl groups in component (C-2) used in the step [(B):(C-2)] is 1:0.15 to 1:1.1. (A) Polyester resin (B) Epoxy group-containing acrylic polymer (C-2) Dihydric alcohols with 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) and the number of carboxyl groups in component (D-2) used in the 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 acids with a number-average molecular weight of 800 or more [Effects of the Invention]

[0015] The method for producing the polyester resin composition of the present invention improves the reduction in the intrinsic viscosity of the polyester resin composition and improves the appearance defects of the molded product. [Modes for carrying out the invention]

[0016] [(A) Polyester resin] There are no particular restrictions on the polyester resin used as component (A) in the present invention, and any polymer consisting of a diol, dicarboxylic acid, or 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, and 4-hydroxycyclohexanecarboxylic acid. Furthermore, examples of cyclic condensates include ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolide, and lactide.

[0017] Examples of polyester resins suitably used in the present invention include polyethylene terephthalate (PET), polyethylene succinate, polybutylene terephthalate, polybutylene succinate, polycaprolactone, poly-L-lactic acid, and polyglycolic acid. Furthermore, the polyester resin may be not only a homopolymer of a single monomer, but also a copolymer using monomers in combination to produce the desired physical properties and characteristics. 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 viewpoint of processability and cost. These polyester resins may be used individually or in any combination of two or more types.

[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 that uses epoxy groups as crosslinking points and 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, as well as glycidyl esters such as methyl methacrylate / glycidyl methacrylate / styrene copolymer. Among these components (B), methyl methacrylate / glycidyl methacrylate / styrene copolymer is preferred from the viewpoint of reaction stability.

[0020] For example, component (B) includes JoncrylADR-4300 and JoncrylADR-4468 (trade names; methyl methacrylate / glycidyl methacrylate / styrene copolymer; manufactured by BASF), which are commercially manufactured and sold, 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, and oleyl alcohol. Among these components (C-1), myristyl alcohol and stearyl alcohol are preferred from the viewpoint of processing stability during the heating and kneading process.

[0022] [(D-1) Aliphatic Carboxylates] The aliphatic carboxylic acid used as component (D-1) in this invention may be any compound having an aliphatic chain and a carboxylic acid structure, for example, it may be 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 components (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, and 2-(4,4-dimethylpentan-2-yl)-5,7 This includes 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 from the viewpoint of processing stability in the heating and kneading process, with stearic acid being particularly preferred.

[0024] [(C-2) Dihydric alcohols with a number-average molecular weight of 800 or more] Examples of dihydric alcohols with a number average molecular weight of 800 or more used as component (C-2) in this invention include polyethylene glycol and polypropylene glycol, both with a number average molecular weight of 800 or more. Among these components (C-2), polyethylene glycol with 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 groups of component (C-2) and the epoxy groups of component (B) during the heating and kneading process. 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] Herein, in this specification, the number-average molecular weight is defined as the number-average molecular weight on a polystyrene basis, determined by size exclusion chromatography (SEC) using tetrahydrofuran (THF) as the solvent.

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

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

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

[0029] [Method 1] In the step of heat-kneading components (A), (B) and (C-1), the charging amounts of components (B) and (C-1) are adjusted such that the ratio of the number of epoxy groups in component (B) to the number of hydroxyl groups in component (C-1) [(B):(C-1)] falls within 1:0.03 to 1:0.28 (preferably 1:0.05 to 1:0.25). By setting the ratio within this range, the hydroxyl groups of component (C-1) react with the epoxy groups of component (B), so that the number of epoxy groups of component (B) that react with component (A) is appropriately reduced. As a result, the reaction between component (A) and component (B) becomes moderate, which can suppress unnecessary crosslinking caused by component (B) functioning as a chain extender, and this is considered to improve poor appearance of molded articles formed from the polyester resin composition.

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

[0031] Furthermore, in Method 1, more specifically, a method of heat-kneading components (A), (B) and (C-1) simultaneously, or a method of adding a heat-kneaded product of components (B) and (C-1) to molten component (A) and then performing heat-kneading can be carried out.

[0032] [Method 2] In the process of heating and kneading components (A), (B), and (D-1), the amounts of components (B) and (D-1) added are adjusted so that the ratio of the number of epoxy groups in component (B) to the number of carboxyl groups in 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 within this range, the carboxyl groups of component (D-1) react with the epoxy groups of component (B), and the number of epoxy groups of component (B) that react with component (A) is appropriately reduced. As a result, the reaction between components (A) and (B) becomes slower, which suppresses unwanted crosslinking by component (B) that functions as a chain extender, and is thought to improve the appearance defects of molded articles of the polyester resin composition.

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

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

[0035] [Method 3] In the process of heating and kneading components (A), (B), and (C-2), the amounts of components (B) and (C-2) added are adjusted so that the ratio of the number of epoxy groups in component (B) to the number of hydroxyl groups in 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 within this range, the hydroxyl groups of component (C-2) react with the epoxy groups of component (B), and the number of epoxy groups of component (B) that react with component (A) is appropriately reduced. As a result, the reaction between components (A) and (B) becomes slower, which suppresses unwanted crosslinking by component (B) that functions as a chain extender, and is thought to improve the appearance defects of molded articles of the polyester resin composition.

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

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

[0038] [Method 4] In the process of heating and kneading components (A), (B), and (D-2), the amounts of components (B) and (D-2) added are adjusted so that the ratio of the number of epoxy groups in component (B) to the number of carboxyl groups in 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 within this range, the carboxyl groups of component (D-2) react with the epoxy groups of component (B), and the number of epoxy groups of component (B) that react with component (A) is appropriately reduced. As a result, the reaction between components (A) and (B) becomes slower, which suppresses unwanted crosslinking by component (B) that functions as a chain extender, and is thought to improve the appearance defects of molded articles of the polyester resin composition.

[0039] Here, the number of carboxyl groups C in component (D-2) per epoxy group of component (B) E This can be calculated according to the following formula (4), based on the amounts of components (B) and (D-2) used, as well as the epoxy group equivalent of component (B) (molecular weight per epoxy group) and the carboxyl group equivalent of component (D-2) (molecular weight per carboxyl group). C E =(W D-2 / E D-2 ) / (W B / E B )···(4) W B : Amount of ingredient (B) added [g] W D-2 : Amount of ingredient (D-2) added [g] E B : Epoxy group equivalent of component (B) [g / eq] E D-2 :Carboxylate group equivalent of component (D-2) [g / eq]

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

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

[0042] For example, from the viewpoint of facilitating molding into films, sheets, etc., it is preferable to produce a polyester resin composition by heating and kneading each of the above components according to the conditions of methods 1 to 4 above, processing the resulting polyester resin composition into a masterbatch, and then blending the masterbatch with polyester resin.

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

[0044] For the heating and mixing process, various types of kneaders can be used, such as Banbury mixers, kneaders, single-screw extruders, and twin-screw extruders. Among these, twin-screw extruders are preferred when considering productivity and kneading power. Twin-screw extruders include twin-screw non-meshing extruders with opposite rotations, twin-screw meshing extruders with opposite rotations, twin-screw non-meshing extruders with coaxial rotations, and twin-screw meshing extruders with coaxial rotations. While any of these can be used, it is preferable to use a twin-screw meshing extruder with coaxial rotations from the viewpoint of kneading power and productivity.

[0045] The heating temperature in the heating and kneading process should be above the melting temperature of component (A) and within a range that does not cause excessive degradation of component (A) and the other components, for example, 200 to 290°C. The heating and kneading time varies depending on the kneader used, heating conditions, etc., but for example, when a twin-screw extruder is used as the kneader, it is 30 seconds to 10 minutes, preferably 1 to 5 minutes.

[0046] The polyester resin composition obtained by the manufacturing method of the present invention may contain other substances commonly used in polyester resins, as long as they do not impair the effects of the present invention. Examples of such additives include antistatic agents, antioxidants, neutralizing agents, nucleating agents, weathering agents, ultraviolet absorbers, and antiblocking agents.

[0047] A molded article can be obtained by molding a polyester resin composition obtained by the manufacturing method of the present invention using a known molding method. Examples include molded articles produced by injection molding methods such as injection molding, injection blow molding, injection compression molding, and foam molding; molded articles produced by extrusion molding methods such as T-die method, inflation method, and lamination, such as pipes and tubes, shaped products, wire coatings, multilayer or single-layer films and sheets, monofilaments, multifilaments, and core-sheath structure fibers; molded articles produced by blow molding, vacuum molding, calendering, compression molding, and pulverization.

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

[0049] [Masterbatch preparation] (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; manufactured by Nacalai Tesque) 3-2) Stearyl alcohol (hydroxyl group equivalent 270.5 g / eq; manufactured by Nacalai Tesque) 4) Component (D-1): Aliphatic carboxylic acid 4-1) Stearic acid (carboxyl group equivalent 284 g / eq; manufactured by Wako Pure Chemical Industries, Ltd.) 4-2) Palmitic acid (carboxyl group equivalent 256 g / eq; manufactured by Wako Pure Chemical Industries, Ltd.) 4-3) Lauric acid (carboxyl group equivalent 200 g / eq; manufactured by Wako Pure Chemical Industries, Ltd.) 5) Component (C-2): A dihydric alcohol with a number-average molecular weight of 800 or more. 5-1) Polyethylene glycol 1 (Product name: PEG-1000; Number average molecular weight 1000; Hydroxyl group equivalent 500 g / eq; Manufactured by Toho Chemical Co., Ltd.) 5-2) Polyethylene glycol 2 (Product name: PEG-1540; Number average molecular weight 1540; Hydroxyl group equivalent 770 g / eq; Manufactured by Toho Chemical Co., Ltd.) 6) Component (D-2): Aliphatic dicarboxylic acid with 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 with a number-average molecular weight of less than 800 7-1) Polyethylene glycol 3 (Product name: PEG-500; Number average molecular weight 500; Hydroxyl group equivalent 250 g / eq; Manufactured by Toho Chemical Co., Ltd.) 8) Component (C-4): Trihydric alcohol 8-1) Glycerin (hydroxyl group equivalent 30.7g / eq; manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 9) Component (D-3): Aliphatic dicarboxylic acid with a number-average molecular weight of less than 800 9-1) Adipic acid (number-average molecular weight 146; carboxyl group equivalent 73 g / eq; manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 10) Component (D-4): Aliphatic tricarboxylic acid 10-1) Trimesic acid (carboxyl group equivalent 70 g / eq; manufactured by Tokyo Chemical Industry Co., Ltd.)

[0050] (2) Masterbatch formulation Tables 1 to 11 show the formulations of the masterbatches prepared using the above raw materials. 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)] (these ratios are hereinafter 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) Method for manufacturing a masterbatch The raw materials listed in Tables 1-11 were weighed to a total of 1000g. Using a twin-screw co-rotating meshing extruder (model: KZW15TW-45MG-NH; ​​screw diameter = 15; L / D = 45; manufactured by Technovel Co., Ltd.), the materials were heated and kneaded at a barrel temperature (C1-C6, H / D) of 180-200°C (C1 = 180°C; C2-C6 = 200°C) and a screw rotation speed of 300 rpm to extrude the polyester resin composition. The extruded polyester resin composition was cut in a pelletizer to produce cylindrical masterbatches (MB1-49) with a diameter of 3mm and a length of 3mm. When all raw materials were in solid form, component (A) was fed into the main feeder of the extruder, and all other raw materials were simultaneously fed into the side feeder of the extruder. Furthermore, when liquid raw materials were available, component (A) was added through the main feeder of the extruder, component (B) through the side feeder of the extruder, and the remaining raw materials were added through the liquid addition line of the extruder.

[0063] [Fabrication and evaluation of polyester resin films] (1) Raw materials 1) Component (A): Polyester resin 1-1) PET (Product name: TRN-8550FF; IV value 0.77 g / dL; manufactured by Teijin Corporation) 2) Masterbatch (MB1~49)

[0064] (2) Formulation of polyester resin film Tables 12-15 show the formulations of polyester resin films made using the above raw materials.

[0065] [Table 12]

[0066] [Table 13]

[0067] [Table 14]

[0068] [Table 15]

[0069] (3) Preparation of polyester resin film Ten times the amount of raw materials listed in Tables 12-15 were kneaded in a single-screw extruder (φ20mm screw L / D=20; cylinder temperature: 280℃), and polyester resin films 1-50 with a film thickness of 50μm were produced by the T-die method.

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

[0071] <Evaluation Criteria> The film surface is smooth and free of roughness: ◎ The film surface has a slight roughness and some visible bumps: ○ The film surface is slightly rough overall, and some imperfections are visible: △ The film surface is generally very rough and has many imperfections: ×

[0072] (5) Measurement of intrinsic viscosity The intrinsic viscosity (IV value) of the fabricated polyester resin films 1-49 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 in Tables 16 and 17, the polyester resin films 1 to 24 obtained by the manufacturing method of the embodiment of the present invention had a film surface condition of "○" or better, and their IV values ​​were higher than those of the control polyester resin film 50 manufactured using only component (A), indicating an improvement in the reduction of the IV value. In contrast, the polyester resin films 25 to 49 obtained by the manufacturing method of the comparative example had a film surface condition of "△" or worse, or their IV values ​​were similar to those of the control polyester resin film 50 manufactured using only component (A), indicating inferiority compared to the present invention.

Claims

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) used in the step [(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 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 carboxyl groups in component (D-1) used in the 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 (D-2), wherein the ratio of the number of epoxy groups in component (B) and the number of carboxyl groups in component (D-2) used in the 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 acids with a number-average molecular weight of 800 or more

Images