Copolymerized polyester resin and molded articles thereof

Abstract

The present invention provides a copolymer polyester resin mainly composed of polybutylene adipate terephthalate, which does not contain urethane bonds in its main chain, has high melt viscosity, and is easy to manufacture. [Solution] A copolymerized polyester resin that satisfies the following (1) to (4). (1) Of the 100 mol% dicarboxylic acid components, 20 to 80 mol% are derived from adipic acid and 20 to 80 mol% are derived from terephthalic acid. (2) Of the 100 mol% of the diol component, 1 to 20 mol% are derived from ethylene glycol and 80 to 99 mol% are derived from 1,4-butanediol. (3) Contains aluminum atoms and phosphorus atoms (4) The reduced viscosity is 1.0 dl / g or higher.

Description

[Technical Field]

[0001] The present invention relates to copolymerized polyester resins and molded articles thereof, as well as to a method for producing copolymerized polyester resins. [Background technology]

[0002] Polybutylene terephthalate (PBT), manufactured from terephthalic acid and 1,4-butanediol, has excellent chemical and physical properties and is used in a wide range of applications such as containers, films, sheets, and fibers.

[0003] Patent Document 1 discloses a copolymerized polyester resin (hereinafter sometimes referred to as PBAT) obtained by copolymerizing terephthalic acid and adipic acid with 1,4-butanediol as a crystalline PBT-based resin. Patent Document 2 first describes polymerizing a low molecular weight polyester composed of terephthalic acid, adipic acid, 1,4-butanediol, and a small amount of glycerin, and then extending the chain length of this with hexamethylene diisocyanate to obtain a high viscosity polyester-polyurethane polymer that appears to have a branched structure. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International release WO2023 / 243609 [Patent Document 2] Special Publication 2011-516709 [Overview of the project] [Problems that the invention aims to solve]

[0005] In Patent Document 1, a mixture of an aluminum compound and a phosphorus compound is used as a polymerization catalyst. However, the low solubility of the aluminum compound and phosphorus compound in the reaction system reduces the efficiency of the reaction by the catalyst, making it difficult to obtain PBAT with a reduction viscosity of 1.0 dL / g or higher. As a result, there were problems such as poor processing suitability for food trays and fibers that require high melt viscosity during molding, and difficulty in melt-mixing with resins that have high melt viscosity, such as polylactic acid. Furthermore, the resin in Patent Document 2 is thought to have room for improvement in terms of its complicated manufacturing process, and because it has urethane bonds in the main chain, hydrolysis gradually progresses even at room temperature, and its long-term durability is not necessarily good.

[0006] The object of the present invention is to provide a copolymer polyester resin mainly composed of polybutylene adipate terephthalate that does not contain urethane bonds in the main chain, has high melt viscosity, and is easy to manufacture. [Means for solving the problem]

[0007] As a result of diligent research to solve the above-mentioned problems, the inventors have found that by using adipic acid and terephthalic acid in predetermined proportions as dicarboxylic acid components, 1,4-butanediol and ethylene glycol as essential diol components, and using aluminum compounds and phosphorus compounds as catalysts during polymerization, the reducing viscosity of copolymerized polyester resin can be increased without performing chain length extension reactions that involve the formation of urethane bonds such as diisocyanates, and without introducing branched structures into the main chain.

[0008] In other words, the present invention includes the following inventions. Section 1. A copolymerized polyester resin that satisfies the following conditions (1) to (4). (1) Of the 100 mol% dicarboxylic acid components, 20 to 80 mol% are derived from adipic acid and 20 to 80 mol% are derived from terephthalic acid. (2) Of the 100 mol% of the diol component, 1 to 20 mol% are derived from ethylene glycol and 80 to 99 mol% are derived from 1,4-butanediol. (3) Contains aluminum atoms and phosphorus atoms (4) The reduced viscosity is 1.0 dl / g or higher. Section 2. The copolymer polyester resin according to item 1, wherein the copolymer polyester resin contains 10 to 100 ppm by mass of aluminum atoms and 20 to 250 ppm by mass of phosphorus atoms. Section 3. A copolymer polyester resin according to item 1 or 2, wherein the color b value is 8 or less. Section 4. A copolymer polyester resin according to any one of claims 1 to 3, wherein the melting point is 50°C or higher. Section 5. A modified copolymer polyester resin as described in any of items 1 to 4. Section 6. A copolymerized polyester resin composition comprising an additive in the copolymerized polyester resin and / or a modified product thereof described in any of items 1 to 4. Section 7. A molded article containing a copolymerized polyester resin as described in any of items 1 to 4. Section 8. A molded article containing the modified substance described in item 5. Section 9. A molded article comprising the copolymerized polyester resin composition described in item 6. [Effects of the Invention]

[0009] The copolymerized polyester resin of the present invention has a reduced viscosity of 1.0 dl / g or higher and possesses high melt viscosity. Therefore, it can be widely used as a material for various molded products such as films, sheets, hollow molded containers, food trays, engineering plastics, and fibers. In this specification, a reduced viscosity of 1.0 dL / g or higher may simply be referred to as "high reduced viscosity."

[0010] The copolymerized polyester resin of the present invention may have suppressed coloration in some cases. Further, the copolymerized polyester resin of the present invention may be excellent in biodegradability in some cases. Resins excellent in biodegradability and / or having suppressed coloration are particularly preferable as materials for various molded articles such as films, sheets, hollow molded containers, trays for food use, engineering plastics, and fibers. Mode for Carrying Out the Invention

[0011] The copolymerized polyester resin of the present invention is typically a resin having a chemical structure obtained by polycondensing a dicarboxylic acid component and a diol component.

[0012] The copolymerized polyester resin of the present invention preferably contains 20 to 80 mol% of adipic acid-derived units, and preferably contains 20 to 80 mol% of terephthalic acid-derived units, based on 100 mol% of the dicarboxylic acid component. It is more preferable to contain 30 to 70 mol% of adipic acid-derived units, and it is even more preferable to contain 40 to 60 mol% of the same. Further, it is more preferable to contain 30 to 70 mol% of terephthalic acid-derived units, and it is even more preferable to contain 40 to 60 mol% of the same. The term "100 mol% of dicarboxylic acid component" means that the total amount of all dicarboxylic acid-derived units is taken as 100 mol%, and the same applies to components other than dicarboxylic acid (diol component, total carboxylic acid component, etc.).

[0013] Based on 100 mol% in total of adipic acid-derived units and terephthalic acid-derived units, it is preferable to contain 20 to 80 mol% of adipic acid-derived units, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%. In other words, based on 100 mol% in total of adipic acid-derived units and terephthalic acid-derived units, it is preferable to contain 20 to 80 mol% of terephthalic acid-derived units, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%.

[0014] Of the total carboxylic acid components at 100 mol%, the units derived from adipic acid and terephthalic acid are preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, particularly preferably 97 mol% or more, most preferably 99 mol% or more, and may be 100 mol%.

[0015] The copolymerized polyester resin of the present invention may contain dicarboxylic acids other than adipic acid and terephthalic acid (hereinafter sometimes referred to as "other dicarboxylic acids"). Other dicarboxylic acids include saturated aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, dimer acid, etc.; and others such as fumaric acid, maleic acid, itaconic acid, etc. Examples include unsaturated aliphatic dicarboxylic acids; orthophthalic acid, isophthalic acid, 5-(alkali metal) sulfoisophthalic acid, diphenic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-biphenylsulfondicarboxylic acid, 4,4'-biphenyletherdicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, pamoic acid, anthracenedicarboxylic acid, and other aromatic dicarboxylic acids. It is preferable that units derived from other dicarboxylic acids constitute 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, particularly preferably 5 mol% or less, most preferably 1 mol% or less, and may even be 0 mol%. When two or more other dicarboxylic acids are used, the proportion of "units derived from other dicarboxylic acids" refers to the total mol% of the other dicarboxylic acids.

[0016] Of the total aromatic dicarboxylic acid components, the units derived from terephthalic acid are preferably 60 mol% or more, more preferably 75 mol% or more, even more preferably 90 mol% or more, particularly preferably 95 mol% or more, most preferably 98 mol% or more, and may also be 100 mol%.

[0017] Of the total aliphatic dicarboxylic acid components, the units derived from adipic acid are preferably 60 mol% or more, more preferably 75 mol% or more, even more preferably 90 mol% or more, particularly preferably 95 mol% or more, most preferably 98 mol% or more, and may be 100 mol%.

[0018] The copolymerized polyester resin of the present invention may contain units derived from carboxylic acid components other than dicarboxylic acid components in small amounts. The carboxylic acids other than dicarboxylic acids may include trivalent or higher polycarboxylic acids, hydroxycarboxylic acids, and cyclic compounds having a structure formed by the dehydration condensation of hydroxycarboxylic acids. The trivalent or higher polycarboxylic acids are preferably trivalent to tetravalent polycarboxylic acids.

[0019] Examples of polycarboxylic acids with a valency of 3 or higher include ethanetricarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, and 3,4,3',4'-biphenyltetracarboxylic acid. It is preferable that units derived from polycarboxylic acids with a valency of 3 or higher are 10 mol% or less, more preferably 5 mol% or less, even more preferably 2 mol% or less, and may even be 0 mol%. When two or more polycarboxylic acids with a valency of 3 or higher are used, the proportion of "units derived from polycarboxylic acids with a valency of 3 or higher" refers to the total mol% of all polycarboxylic acids with a valency of 3 or higher.

[0020] Examples of hydroxycarboxylic acids include lactic acid, citric acid, malic acid, tartaric acid, hydroxyacetic acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and 4-hydroxycyclohexanecarboxylic acid. Examples of cyclic compounds having a structure formed by the dehydration condensation of hydroxycarboxylic acids include lactones such as ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, and δ-valerolactone, as well as glycosides and lactides. Of 100 mol% of the total carboxylic acid components, units derived from hydroxycarboxylic acids and cyclic compounds having a structure formed by the dehydration condensation of hydroxycarboxylic acids are preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 2 mol% or less, and may be 0 mol%. When two or more hydroxycarboxylic acids and cyclic compounds having a structure formed by the dehydration condensation of hydroxycarboxylic acids are used, the proportion of "units derived from hydroxycarboxylic acids" means the mol% of the total of all hydroxycarboxylic acids.

[0021] Dicarboxylic acids, polycarboxylic acids with three or more valent values, and hydroxycarboxylic acids may be used as ester-forming derivatives thereof, such as alkyl esters, acid chlorides, and acid anhydrides. In this specification, "units derived from acid" includes not only units derived from the acid itself but also units derived from the ester-forming derivatives of the acid.

[0022] The copolymerized polyester resin of the present invention preferably contains 80 to 99 mol% of units derived from 1,4-butanediol in 100 mol% of the diol component.

[0023] The copolymerized polyester resin of the present invention contains 1 to 20 mol% of ethylene glycol-derived units per 100 mol% of the diol component. By including ethylene glycol as one of the essential components, high reductive viscosity of the copolymerized polyester can be achieved. This is thought to be because the presence of ethylene glycol in the reaction system improves the solubility of the phosphorus compound and aluminum compound, which are polymerization catalysts, thereby improving the efficiency of the catalytic reaction.

[0024] The diol component (glycol component) may include diols other than 1,4-butanediol and ethylene glycol (hereinafter sometimes referred to as "other diols"). Examples of other diols include alkylene glycols such as 1,2-propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,10-decamethylene glycol, 1,12-dodecanediol, etc.; and oligoalkylene ether glycols such as diethylene glycol and triethylene glycol, etc. Examples of polyalkylene ether glycols include polyethylene glycol, polytrimethylene glycol, and polytetramethylene glycol; and diols having aromatic groups, such as hydroquinone, 4,4'-dihydroxybisphenol, 1,4-bis(β-hydroxyethoxy)benzene, 1,4-bis(β-hydroxyethoxyphenyl)sulfone, bis(p-hydroxyphenyl)ether, bis(p-hydroxyphenyl)sulfone, bis(p-hydroxyphenyl)methane, 1,2-bis(p-hydroxyphenyl)ethane, bisphenol A, bisphenol C, 2,5-naphthalenediol, and glycols having a structure in which an alkylene oxide such as ethylene oxide is added to these glycols.

[0025] Of the total 100 mol% of diol components, units derived from other diols are preferably 19 mol% or less, more preferably 10 mol% or less, even more preferably 5 mol% or less, and may even be 0 mol%. When two or more other diols are used, the proportion of "units derived from other diols" refers to the total mol% of the other diols.

[0026] The copolymerized polyester resin of the present invention may contain units derived from polyhydric alcohol components other than the diol component in small amounts. That is, a polyhydric alcohol of trivalent or higher may be used in combination as the polyhydric alcohol component other than the diol component. Preferably, the polyhydric alcohol of trivalent or higher is a polyhydric alcohol of tetravalent or higher. Examples of polyhydric alcohols of trivalent or higher include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol, and hexanetriol.

[0027] Of the total 100 mol% of polyhydric alcohol components, units derived from trihydric or higher polyhydric alcohols are preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 2 mol% or less, and may even be 0 mol%. When two or more trihydric or higher polyhydric alcohols are used, the proportion of "units derived from trihydric or higher polyhydric alcohols" refers to the total mol% of all trihydric or higher polyhydric alcohols.

[0028] 1,4-butanediol, ethylene glycol, other diols, and polyhydric alcohols of trivalent or higher can be used as ester-forming derivatives of these diols. In this specification, "units derived from 1,4-butanediol and ethylene glycol" includes not only units derived from 1,4-butanediol and ethylene glycol, but also units derived from ester-forming derivatives of 1,4-butanediol and ethylene glycol. The same applies to other diols and polyhydric alcohols of trivalent or higher.

[0029] The amount of units derived from cyclic esters is preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 2 mol% or less, and may even be 0 mol%, relative to 100 mol% of the total amount of carboxylic acid components and polyhydric alcohol components. When two or more cyclic esters are used, the proportion of "units derived from cyclic esters" refers to the mol% of the total amount of all cyclic esters.

[0030] [Polymerization catalyst] The copolymerized polyester resin of the present invention is manufactured using a polymerization catalyst consisting of an aluminum compound and a phosphorus compound. As a result, the copolymerized polyester resin of the present invention contains catalytic amounts of components derived from the aluminum compound and the phosphorus compound. In other words, the copolymerized polyester resin of the present invention contains aluminum atoms and phosphorus atoms.

[0031] <Aluminum compounds> The aluminum compound constituting the polymerization catalyst described above is not limited as long as it is soluble in the solvent, and any known aluminum compound can be used without limitation. Examples of aluminum compounds include carboxylates such as aluminum formate, aluminum acetate, basic aluminum acetate, aluminum propionate, aluminum oxalate, aluminum acrylate, aluminum laurate, aluminum stearate, aluminum benzoate, aluminum trichloroacetate, aluminum lactate, aluminum citrate, aluminum tartrate, and aluminum salicylate; inorganic salts such as aluminum chloride, aluminum hydroxide, aluminum chloride hydroxide, aluminum nitrate, aluminum sulfate, aluminum carbonate, aluminum phosphate, and aluminum phosphonate; aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, and aluminum i Examples include aluminum alkoxides such as sopropoxide, aluminum n-butoxide, and aluminum t-butoxide; chelate compounds such as aluminum acetylacetonate, aluminum ethylacetoacetate, and aluminum ethylacetoacetate diiso-propoxide; organoaluminum compounds such as trimethylaluminum and triethylaluminum and their partial hydrolysates; reaction products consisting of aluminum alkoxides or aluminum chelate compounds with hydroxycarboxylic acids; aluminum oxide, ultrafine particle aluminum oxide, aluminum silicate, and composite oxides of aluminum with titanium, silicon, zirconium, alkali metals, alkaline earth metals, etc. Of these, at least one selected from carboxylates, inorganic acid salts, and chelate compounds is preferred, and among these, at least one selected from aluminum acetate, basic aluminum acetate, aluminum chloride, aluminum hydroxide, aluminum chloride hydroxide, and aluminum acetylacetonate is more preferred, at least one selected from aluminum acetate and basic aluminum acetate is particularly preferred, and basic aluminum acetate is most preferred.

[0032] The above aluminum compound is preferably an aluminum compound that dissolves in water or glycol. Examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, trimethylene glycol, ditrimethylene glycol, tetramethylene glycol, ditetramethylene glycol, and neopentyl glycol. Butanediol or ethylene glycol is preferred. It is preferable to use a solution in which the aluminum compound is dissolved in water or butanediol or ethylene glycol, as this allows the effects of the present invention to be clearly expressed. The amount of aluminum compound to be added will be described later.

[0033] <Phosphorus compounds> The phosphorus compound constituting the polymerization catalyst of the present invention is not particularly limited, but phosphonic acid compounds and / or phosphinic acid compounds are preferred because they greatly improve catalytic activity, and among these, phosphonic acid compounds are more preferred because they particularly greatly improve catalytic activity.

[0034] As the above phosphorus compound, a phosphorus compound having both a phosphorus element and a phenol structure within the same molecule is preferred. While there are no particular limitations as long as the phosphorus compound has both a phosphorus element and a phenol structure within the same molecule, using one or more compounds selected from the group consisting of phosphonic acid compounds having both a phosphorus element and a phenol structure within the same molecule, and phosphinic acid compounds having both a phosphorus element and a phenol structure within the same molecule, is more preferable as it enhances catalytic activity more significantly, and using one or more phosphonic acid compounds having both a phosphorus element and a phenol structure within the same molecule is even more preferable as it enhances catalytic activity even more significantly.

[0035] Furthermore, as a phosphorus compound having both a phosphorus element and a phenol structure within the same molecule, P(=O)R 1 (OR 2 )(OR 3 ) and P(=O)R 1 R 4 (OR2 ) represented by the formula, and the like. R 1 represents a substituent having 6 to 50 carbon atoms containing a phenol structure, or a substituent having 6 to 50 carbon atoms containing a phenol structure and further containing a substituent that is a hydroxyl group, a halogen group, an alkoxy group or an amino group. R 4 represents hydrogen, an alkyl group having 1 to 50 carbon atoms, a hydroxyl group, a halogen group or an amino group; or a substituent having 1 to 50 carbon atoms containing one or more substituents that are a hydroxyl group, a halogen group, an alkoxy group and / or an amino group. R 2 , R 3 each independently represent hydrogen, an alkyl group having 1 to 50 carbon atoms, a hydroxyl group, a halogen group, an amino group, or an alkoxy group; or a substituent having 1 to 50 carbon atoms containing one or more substituents that are a hydroxyl group, a halogen group, an alkoxy group and / or an amino group. Provided that the hydrocarbon group may contain a branched structure, an alicyclic structure such as cyclohexyl, or an aromatic ring structure such as phenyl or naphthyl. The terminals of R2 and R4 may be bonded to each other.

[0036] Examples of the phosphorus compound having a phosphorus element and a phenol structure in the same molecule include p-hydroxyphenylphosphonic acid, dimethyl p-hydroxyphenylphosphonate, diethyl p-hydroxyphenylphosphonate, diphenyl p-hydroxyphenylphosphonate, bis(p-hydroxyphenyl)phosphinic acid, methyl bis(p-hydroxyphenyl)phosphinate, phenyl bis(p-hydroxyphenyl)phosphinate, p-hydroxyphenylphosphinic acid, methyl p-hydroxyphenylphosphinate, phenyl p-hydroxyphenylphosphinate, and dialkyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate represented by the following (Chemical Formula 1). The phosphorus compound having a phosphorus element and a phenol structure in the same molecule is particularly preferably a phosphorus compound having a hindered phenol structure, and among these, dialkyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate shown in the following (Chemical Formula 1) is preferred.

[0037] [Chemical formula] (In (Formula 1), X 1 , X 2 (These represent hydrogen and an alkyl group with 1 to 4 carbon atoms, respectively.)

[0038] The above X 1 and X 2 The alkyl group preferably has 1 to 4 carbon atoms, and more preferably 1 to 2 carbon atoms. In particular, the above X 1 and X 2 Diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, an ethyl ester derivative with two carbon atoms in the alkyl group, is also preferable because it is readily available and commercially sold by BASF as Irganox1222.

[0039] In this invention, the phosphorus compound is preferably the 3,5-di-tert-butyl-4-hydroxybenzylphosphonate dialkyl shown in (Chemical Formula 1) above, but it also includes modified forms of 3,5-di-tert-butyl-4-hydroxybenzylphosphonate dialkyl represented by the following nine chemical formulas. The modified forms will be described below.

[0040] When using the 3,5-di-tert-butyl-4-hydroxybenzylphosphonate dialkyl shown in (Chemical Formula 1) above as the phosphorus compound, a portion of the 3,5-di-tert-butyl-4-hydroxybenzylphosphonate dialkyl shown in (Chemical Formula 1) undergoes a structural change during the heat treatment described above. For example, the t-butyl group is removed, the ethyl ester group is hydrolyzed, and the structure changes to a hydroxyethyl transesterification structure (a transesterification structure with ethylene glycol). Therefore, in the present invention, the phosphorus compound includes not only the 3,5-di-tert-butyl-4-hydroxybenzylphosphonate dialkyl shown in (Chemical Formula 1) but also other phosphorus compounds that have undergone structural changes. Note that the removal of the t-butyl group occurs significantly at the high temperatures of the polymerization process.

[0041] The following describes nine phosphorus compounds in which a portion of 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl has undergone a structural change. The amount of each structurally altered phosphorus compound in the glycol solution can be quantified by P-NMR spectroscopy of the solution. The amount of phosphorus compound added will be discussed later.

[0042] [ka]

[0043] <Catalysts other than aluminum compounds and phosphorus compounds> Furthermore, in addition to the aluminum and phosphorus compounds described above, other polymerization catalysts such as antimony compounds, germanium compounds, and titanium compounds may be used in combination in the present invention, to the extent that they do not cause problems with the properties, processability, color tone, or other characteristics of the copolymerized polyester resin of the present invention.

[0044] The content of antimony in the copolymerized polyester resin of the present invention is preferably 100 ppm by mass or less, more preferably 50 ppm by mass or less, and even more preferably 20 ppm by mass or less. The content of germanium in the copolymerized polyester resin of the present invention is preferably 40 ppm by mass or less, more preferably 20 ppm by mass or less. The content of titanium in the copolymerized polyester resin of the present invention is preferably 10 ppm by mass or less, and more preferably 5 ppm by mass or less. In this specification, ppm by mass means 10 -4 This represents a percentage of mass.

[0045] [Method for producing copolymerized polyester resin] The method for producing the copolymerized polyester resin of the present invention can be carried out by a known method, except that terephthalic acid, adipic acid, ethylene glycol, and 1,4-butanediol are used as monomers in predetermined proportions, and a polyester polymerization catalyst consisting of an aluminum compound and a phosphorus compound is used as a catalyst.

[0046] An example of a method for producing the copolymer polyester resin of the present invention is a method comprising: a first step of esterifying and / or transesterifying a dicarboxylic acid (dicarboxylic acid component) containing 20-80 mol% terephthalic acid and 20-80 mol% adipic acid with a diol (diol component) containing 80-99 mol% 1,4-butanediol and 1-20 mol% ethylene glycol; and a second step of polycondensing the reactant obtained in the first step.

[0047] Examples of esterification reactions include a direct esterification method in which adipic acid, terephthalic acid, 1,4-butanediol, ethylene glycol, and optionally other copolymer components are directly reacted, water is removed by distillation to esterify, and then polycondensation is carried out under atmospheric or reduced pressure. Examples of transesterification reactions include a production method in which ester-forming derivatives such as dimethyl terephthalate and adipine dimethyl, 1,4-butanediol, ethylene glycol, and optionally other copolymer components are reacted, methyl alcohol is removed by distillation to transesterify, and then polycondensation is carried out under atmospheric or reduced pressure. Furthermore, solid-phase polymerization may be carried out as needed to increase the reducing viscosity and melt viscosity.

[0048] In any of these methods, the esterification or transesterification reaction may be carried out in one step or in multiple steps. The polycondensation in the second step may be carried out in one step or in multiple steps. Furthermore, the polycondensation in the second step may be carried out solely by melt polymerization, or the copolymerized polyester resin produced by melt polymerization may be further polymerized by solid-phase polymerization.

[0049] In order to shorten the time required for the first and second steps, it is necessary to add the aluminum compound and phosphorus compound as polymerization catalysts no later than the completion of the first step.

[0050] In reactions using 1,4-butanediol as a raw material, a side reaction in which tetrahydrofuran is produced is likely to occur. To suppress this side reaction, it is preferable to carry out the esterification or transesterification reaction at the lowest possible temperature. For this reason, it is preferable to add the aluminum compound and the phosphorus compound before or during the first step, and it is more preferable to add the aluminum compound and the phosphorus compound before the first step. The above-mentioned "before the first step" includes the point in time when the production of the copolymerized polyester resin begins.

[0051] The aluminum compound and phosphorus compound as polymerization catalysts may be added in their entirety at once or continuously. "Continuous addition" means continuing the addition at a constant rate, and includes continuing to add a constant amount with periods of pause between additions. When adding continuously, it is preferable that the addition of the aluminum compound and phosphorus compound as polymerization catalysts be completed by the end of the first step at the latest, more preferably completed during the first step, and even more preferably completed before the start of the first step.

[0052] As for the method of adding aluminum compounds and phosphorus compounds as catalysts, it is preferable to add them in slurry or solution form, more preferably in a solvent such as water or glycol, even more preferably in a glycol, and most preferably in a 1,4-butanediol and / or ethylene glycol. By using the above addition method, catalytically active complexes are functionally formed in the polymerization system, and sufficient polymerization activity can be exhibited.

[0053] As a method for adding aluminum compounds and phosphorus compounds as catalysts, it is preferable to add a solution containing the aluminum compound and a solution containing the phosphorus compound simultaneously. More preferably, the aluminum compound solution and the phosphorus compound solution are mixed beforehand to prepare a mixed solution so that the ratio of aluminum and phosphorus elements is a predetermined ratio described later, and then the liquefied mixed solution is added. Methods for pre-liquefying the solutions include mixing each solution in a tank, or merging the piping for catalyst addition midway and mixing the solutions. By simultaneously adding the aluminum compound solution and the phosphorus compound solution, a complex formation reaction occurs between the aluminum compound and the phosphorus compound, and a complex of aluminum and phosphorus compounds that provides polymerization activity can be quickly and efficiently produced. As a result, it is preferable because it is possible to maintain a state that is favorable for both improving polymerization activity and suppressing the amount of foreign matter. If the aluminum compound and the phosphorus compound are added separately, a complex of aluminum and phosphorus compounds that provides polymerization activity may not be sufficiently produced, and as a result, the amount of foreign matter in the resulting resin may not be sufficiently suppressed.

[0054] <Amount and content of aluminum and phosphorus atoms added> The copolymerized polyester resin of the present invention preferably contains 10 to 100 ppm by mass of aluminum, more preferably 20 to 80 ppm by mass, and even more preferably 30 to 70 ppm by mass. If the aluminum content is 10 ppm by mass or more, sufficient polymerization activity is exhibited. On the other hand, if it is 100 ppm by mass or less, catalyst costs can be suppressed.

[0055] The aluminum element in the aluminum compound that functions as a catalyst remains in the copolymerized polyester resin produced by polymerization, even when the copolymerized polyester resin is subjected to a reduced pressure environment, with almost 100% of the amount initially added to the system as a catalyst remaining in the copolymerized polyester resin. In other words, since the amount of aluminum compound does not change significantly before and after polycondensation, it is preferable to add 10 to 100 ppm by mass of aluminum element to the resulting copolymerized polyester resin, more preferably 20 to 80 ppm by mass, and even more preferably 30 to 70 ppm by mass. As mentioned above, the amount of "the copolymerized polyester resin produced" can be calculated from the amount of monomers such as adipic acid and terephthalic acid charged.

[0056] The copolymerized polyester resin of the present invention preferably contains 20 to 250 ppm by mass of phosphorus, more preferably 30 to 200 ppm by mass, even more preferably 40 to 150 ppm by mass, and particularly preferably 60 to 140 ppm by mass. If the phosphorus content is 20 ppm by mass or more, polymerization activity is sufficiently exhibited and the amount of foreign matter can be suppressed. On the other hand, if it is 250 ppm by mass or less, catalyst costs can be suppressed.

[0057] In copolymerized polyester resins, the content ratio of phosphorus elements to aluminum elements is preferably 1.1 to 2.1, more preferably 1.2 to 1.9, and even more preferably 1.3 to 1.8. As described above, the aluminum and phosphorus elements in the copolymerized polyester resin originate from the aluminum compound and phosphorus compound used as polymerization catalysts for the copolymerized polyester resin, respectively. By using these aluminum and phosphorus compounds in a specific ratio, a catalytically active complex is functionally formed in the polymerization system, allowing for sufficient polymerization activity. If the content ratio of phosphorus elements to aluminum elements is 1.1 or higher, sufficient thermal stability and thermal oxidation stability are achieved, and the amount of foreign matter can be suppressed. On the other hand, if the content ratio of phosphorus atoms to aluminum atoms is 2.1 or lower, the catalyst cost due to increased addition of phosphorus compounds can be suppressed.

[0058] When phosphorus compounds are added to a copolymerized polyester resin under reduced pressure during polymerization, a portion of the initial amount (approximately 10-40%) is typically removed from the system. Therefore, it is advisable to adjust the amount added to account for this removal.

[0059] [Resins other than polyester resins] The copolymerized polyester resin of the present invention may contain resins other than polyester resin, as long as they do not hinder the objectives of the present invention. The resins other than polyester resin are not particularly limited, but examples include polyolefin resins, polyamide resins, polyacetal resins, and acrylic resins. The content of resins other than polyester resin in the copolymerized polyester resin is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, particularly preferably 3% by mass or less, and most preferably 1% by mass or less. The method of blending the above resins with the polyester resin is not particularly limited, and examples include adding the resins during the manufacturing process of the polyester resin, dry blending with the polyester resin after manufacturing, and other methods that allow for uniform mixing.

[0060] [Modified polyester resins] Modified copolymer polyester resins can be produced by modifying the copolymer polyester resin of the present invention using various chemical reactions. For example, epoxy-modified copolymer polyester resins can be obtained by epoxy modification using epoxy compounds.

[0061] Epoxy modification can be synthesized by known methods, such as adding an acid anhydride like trimellitic anhydride or phthalic anhydride to the terminal hydroxyl groups of a polyester resin to perform terminal carboxyl modification, and then epoxy-modifying the epoxy resin with these carboxyl groups in the presence of a catalyst such as triphenylphosphine. Alternatively, carboxyl groups may be introduced by using a carboxyl group-containing glycol such as dimethylolpropionic acid as a chain extender.

[0062] The epoxy resin-derived units are preferably 5 mol% or less, more preferably 4 mol% or less, and even more preferably 3 mol% or less, relative to 100 mol% of the total carboxylic acid and polyhydric alcohol components. When two or more epoxy resins are used, the proportion of "epoxy-derived units" refers to the mol% of the total of all epoxy resins.

[0063] [Additives] The copolymerized polyester resin of the present invention may be a resin composition that appropriately contains various known additives, as long as they do not hinder the objectives of the present invention. Examples of additives include leveling agents, defoaming agents, fine particle dispersants, antioxidants, bluing agents, antistatic agents, light stabilizers, weather resistance imparters, and colorants.

[0064] <Leveling agent> Leveling agents may be added to obtain smoothness in molded articles obtained from copolymerized polyesters. Examples of leveling agents include silicone-based leveling agents, fluorine-based leveling agents, acrylic-based leveling agents, vinyl-based leveling agents, and leveling agents that are composites of fluorine-based and acrylic-based agents, and can be used depending on the purpose. By adding a leveling agent, the leveling agent functions on the surface of the coating film and can reduce the surface tension. When the purpose is to reduce surface tension, it is preferable to use a silicone-based leveling agent or a fluorine-based leveling agent, and when the purpose is to reduce the occurrence of wetting defects, it is preferable to use an acrylic-based leveling agent or a vinyl-based leveling agent.

[0065] As silicone-based leveling agents, for example, copolymers of polyoxyalkylene and polydimethylsiloxane can be used. Commercially available silicone-based leveling agents include FZ-2118, FZ-77, FZ-2161, etc. from Toray Dow Corning; KP321, KP323, KP324, KP326, KP340, KP341, etc. from Shin-Etsu Chemical Co., Ltd.; TSF4440, TSF4441, TSF4445, TSF4450, TSF4446, TSF4452, TSF4453, TSF4460, etc. from Momentive Performance Materials Japan LLC; and BYK from BIC Chemie Japan. Examples include polyether-modified silicone oils (polyoxyalkylene-modified silicone oils) such as -300, BYK-302, BYK-306, BYK-307, BYK-320, BYK-325, BYK-330, BYK-331, BYK-333, BYK-337, BYK-341, BYK-344, BYK-345, BYK-346, BYK-348, BYK-377, BYK-378, BYK-UV3500, BYK-3510, and BYK-3570.

[0066] Furthermore, when heat resistance of 150°C or higher is required, polyester-modified silicone oil or aralkyl-modified silicone oil containing a benzene ring is suitable as a leveling agent. Commercially available polyester-modified silicone oils include BYK-310, BYK-315, and BYK-370 from BIC Chemie Japan. Commercially available aralkyl-modified silicone oils containing a benzene ring include BYK-322 and BYK-323 from BIC Chemie Japan.

[0067] As a fluorine-based leveling agent, for example, a copolymer of polyoxyalkylene and fluorocarbon can be used. Commercially available fluorine-based leveling agents include the MEGAFAC series from DIC Corporation and the FC series from Sumitomo 3M Corporation.

[0068] Commercially available vinyl leveling agents can be used as acrylic leveling agents. Examples of commercially available acrylic leveling agents include BYK-350, BYK-352, BYK-354, BYK-355, BYK358N, BYK-361N, BYK-380N, BYK-381, BYK-392, etc. from BIC Chemie Japan, as well as BYK-340 which contains fluorine, and No. 90 from Kyoeisha Chemical.

[0069] Commercially available vinyl leveling agents can be used as vinyl leveling agents. Examples of commercially available vinyl leveling agents include the Disparon series manufactured by Kusumoto Kasei Co., Ltd.

[0070] By incorporating such a leveling agent, the finished appearance of the molded article is improved, and it can be applied uniformly even as a thin film. The amount of leveling agent used is preferably 0.01 to 10% by mass, more preferably 0.02 to 5% by mass, based on the total amount of the composition.

[0071] The leveling agent may be incorporated when preparing the composition for creating the molded body, or it may be incorporated into the composition immediately before forming the molded body, or it may be incorporated at both stages: the preparation of the composition for creating the molded body and immediately before forming the molded body.

[0072] [Physical properties of copolymerized polyester resins] The copolymerized polyester resin of the present invention preferably has a reduced viscosity of 1.0 dL / g or more, more preferably 1.1 dL / g or more, and even more preferably 1.3 dL / g. Details of the method for measuring the reduced viscosity will be described later, but it is a measurement method in accordance with JIS K7367-5:2000. When the reduced viscosity of the copolymerized polyester resin is within the above range, it can be melt-mixed with resins having a high melt viscosity, such as polylactic acid.

[0073] The copolymerized polyester resin of the present invention preferably has an acid value of 3 to 80 eq / ton, more preferably 5 to 60 eq / ton, and even more preferably 8 to 40 eq / ton. Details of the method for measuring the acid value will be described later, but it is a measurement method in accordance with the neutralization titration method of JIS K0070-1992.

[0074] In this invention, the b-value of the copolymer polyester resin pellets is preferably 8 or less, more preferably 6 or less, even more preferably 4 or less, and particularly preferably 3 or less. The b-value of the pellets is shown in yellow / blue coordinates, where positive values ​​indicate yellow and negative values ​​indicate blue. The b-value of the pellets is closely related to the appearance defects caused by the yellowing of the molded product. By setting the b-value of the pellets to 8 or less, the yellowing of the molded product can be suppressed. The lower limit is not particularly limited, but for example it is 0 or more, and preferably 1 or more. Details of the method for measuring the b-value of the pellets will be described later, but it is a measurement method in accordance with JIS Z8722:2009 and JIS Z8781-4:2013.

[0075] The copolymerized polyester resin of the present invention preferably has a melting point, more preferably 50°C or higher, even more preferably 70-180°C, and particularly preferably 90-150°C, from the viewpoint of increasing the mechanical strength of the molded product obtained from the resin. Details of the method for measuring the melting point will be described later, but it is a measurement method in accordance with JIS K7121. [Examples]

[0076] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The evaluation methods used in each example and comparative example are as follows, and copolymerized polyester resin may be simply referred to as "resin".

[0077] <Resin composition> 20 mg of a polyester resin was dissolved in 0.6 mL of a mixed solvent of trifluoroacetic acid / deuterated dichloromethane (15 / 85 by volume), followed by centrifugation. Thereafter, the supernatant was collected, subjected to ¹H-NMR measurement, and the resin composition was identified from the NMR spectrum. ¹H-NMR measurement was carried out with the following apparatus and conditions. • Apparatus: Fourier transform nuclear magnetic resonance spectrometer (manufactured by BRUKER, AVANCE NEO600) • 1 ¹H resonance frequency: 600.13 MHz • Lock solvent: deuterated dichloromethane • Flip angle: 30° • Data acquisition time: 4 seconds • Delay time: 30 seconds • Measurement temperature: 30°C

[0078] <Reduced viscosity> 0.1 g of a resin was dissolved in 25 mL of a mixed solvent of phenol and tetrachloroethane at a mass ratio of 60:40 to prepare a solution. The falling time of the above solution and the above mixed solvent was measured using an Ubbelohde viscometer temperature-controlled at 30°C, and the reduced viscosity was determined.

[0079] <Acid value> 0.2 g of a resin was dissolved in 40 mL of chloroform and titrated with a 0.01 N potassium hydroxide ethanol solution, and the equivalent per ton of polyester (eq / ton) was determined. Phenolphthalein was used as an indicator.

[0080] Approximately 50 g of resin pellets were filled into a measurement cell, measurement was carried out while rotating the cell, the tristimulus values X, Y and Z representing the fundamental stimulus quantities of color were measured, and the b value of the pellets was calculated with reference to JIS Z8781-4:2013. A higher value indicates a stronger yellow tint. Apparatus: Precision spectrophotometric colorimeter TC-1500SX, manufactured by Tokyo Denshoku Co., Ltd. Measurement method: In accordance with JIS Z8722, transmitted light, 0 degree, -0 degree method Detection element: silicon photodiode array Light source: Halogen lamp 12V 100W 2000H Measurement area: Transmission 25mmφ Humidity temperature condition: 25℃, RH50% Measuring cell: φ35mm, height 25mm, rotary type (pellet) Measurement details: X, Y, Z3 stimulus values ​​CIE chromaticity coordinates x=X / (X+Y+Z), y=Y / (X+Y+Z)

[0081] <Melting point> 5.0 mg of resin was added to an aluminum pan, sealed by holding down the lid, and measured using a differential scanning calorimetry analyzer (DSC7020, Hitachi High-Tech Science Corporation) under the following conditions: The temperature was increased from 20°C to 220°C at a rate of 20°C / min, and held for 3 minutes to completely melt the sample. Next, it was cooled to -150°C at a rate of 50°C / min, held for 3 minutes, and then heated again to 220°C at a rate of 20°C / min. The temperature of the endothermic peak in the thermogram curve obtained during the second heating was defined as the melting point.

[0082] (Example 1) In a 5L stainless steel autoclave equipped with a stirrer, 592.6g of high-purity terephthalic acid, 521.4g of adipic acid, 900.2g of 1,4-butanediol, and 52.3g of ethylene glycol were added together. A mixture of aluminum-containing ethylene glycol solution and phosphorus-containing ethylene glycol solution was then added, and the mixture was heated to 265°C under a nitrogen atmosphere, continuing the reaction until it became clear. After it became clear, the temperature was lowered to 240°C to obtain a polyester oligomer. Basic aluminum acetate was used as the aluminum compound and Irganox 1222 (3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl) manufactured by BASF Corporation was used as the phosphorus compound in the preparation of the above mixture. Furthermore, the above mixture was prepared so that the aluminum and phosphorus elements were present in concentrations of 45 ppm and 84 ppm by mass, respectively, relative to the mass of the polyester oligomer. The amount of copolymerized polyester resin produced can be calculated from the amount of terephthalic acid and adipic acid added. In this example, the above mixture was added to 1500 g of copolymerized polyester resin so that the aluminum atoms were 45 ppm by mass and the phosphorus atoms were 84 ppm by mass. Subsequently, the pressure of the system was gradually reduced to 0.15 Pa over 1 hour, and the polycondensation reaction was carried out under these conditions to obtain a copolymerized polyester resin with a reduced viscosity of 1.34 dL / g and an acid value of 39 eq / ton. The b value of the copolymerized polyester resin solution was 0.2, and the melting point was 124°C.

[0083] (Examples 2-3, Comparative Example 1) Copolymerized polyester resins were prepared in the same manner as in Example 1, except that the catalyst added to the aromatic dicarboxylic acid, aliphatic dicarboxylic acid, diol, and oligomer, and the type and amount of the catalyst added were changed to those listed in Table 1.

[0084] (Comparative Example 2) The results of Example 1 from International Publication WO2023 / 243609 are transcribed in Table 1. The description of the method for producing the polyester resin in Example 1 of International Publication WO2023 / 243609 is transcribed below. In a 2L stainless steel autoclave equipped with a stirrer, 197.8g of high-purity terephthalic acid, 173.8g of adipic acid, and 385.8g of 1,4-butanediol were added together. A mixture of aluminum-containing butanediol solution and phosphorus-containing butanediol solution was then added to the autoclave. The mixture was heated to 260°C under a nitrogen atmosphere and the reaction was continued until it became clear. After it became clear, the temperature was lowered to 250°C to obtain a polyester oligomer. In preparing the above mixture, basic aluminum acetate was used as the aluminum compound, and Irganox 1222 (3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl) manufactured by BASF was used as the phosphorus compound. The mixture was prepared so that the aluminum atoms and phosphorus atoms were 50 ppm by mass and 110 ppm by mass, respectively, relative to the mass of the polyester oligomer. The amount of copolymerized polyester resin produced can be calculated from the amount of terephthalic acid and adipic acid added. In this example, the above mixture was added so that the aluminum atoms were 50 ppm by mass and the phosphorus atoms were 110 ppm by mass for 500 g of copolymerized polyester resin produced. Subsequently, the pressure of the system was gradually reduced to 0.15 Pa over 1 hour, and a polycondensation reaction was carried out under these conditions to obtain a copolymerized polyester resin with a reduced viscosity of 0.91 dl / g and an acid value of 10 eq / ton. The copolymerized polyester resin contained 50 ppm by mass of aluminum atoms and 88 ppm by mass of phosphorus atoms. The b-value of the copolymerized polyester resin solution was 2.2, the amount of foreign matter with a particle size of 0.3-0.5 μm was 3000 particles / mL, the melting point was 126°C, and the mass loss rate was 89%.

[0085] (Comparative Example 3) In the twin-screw kneader prepared in Comparative Example 1, 12.0 g of the copolymerized polyester prepared in Comparative Example 1 and 36 mg of hexamethylene diisocyanate (HDI) were added. The mixture was heated to 245°C under a nitrogen atmosphere and reacted for 5 minutes to obtain a copolymerized polyester with a reduced viscosity of 1.8 dL / g.

[0086] Table 1 shows the physical properties of the copolymerized polyester resins obtained in Examples 1-3 and Comparative Examples 1-3. In Table 1, cases where the catalyst is added before the esterification reaction are referred to as "pre-added catalyst," and cases where the catalyst is added after the esterification reaction but before polycondensation are referred to as "post-added catalyst." Aluminum atoms are denoted as Al, phosphorus atoms as P, and titanium atoms as Ti.

[0087] When the b-values ​​of the pellets were measured for Examples 1-3 and Comparative Example 1, the b-values ​​of the copolymer polyester resin pellets in Examples 1-3 were 1 or less, while the b-value of the copolymer polyester resin pellets in Comparative Example 1, which used a titanium compound as a catalyst, was 13.3. It is thought that the b-value in Comparative Example 1 was higher due to the generation of foreign matter originating from the titanium compound.

[0088] When comparing the reduced viscosity of Example 1 and Comparative Example 2, Example 1, which contains ethylene glycol in its copolymerized polyester resin composition, had a reduced viscosity of 1.3 dl / g, while Comparative Example 2, which does not contain ethylene glycol, had a reduced viscosity of 0.9 dl / g. It is thought that in Example 1, the presence of ethylene glycol in the reaction system improved the solubility of the aluminum compound and phosphorus compound, which are polymerization catalysts, thereby improving the efficiency of the catalytic reaction and resulting in a higher reduced viscosity.

[0089] Comparative Example 3 exhibits high reducing viscosity, which is thought to be due to the introduction of urethane bonds derived from isocyanate, resulting in a higher molecular weight. The addition of isocyanate requires an additional step compared to the case without isocyanate, and is therefore undesirable from the standpoint of cost and energy efficiency.

[0090] [Table 1] [Industrial applicability]

[0091] The copolymerized polyester resin of the present invention has a reduced viscosity of 1.0 dl / g or higher and a high melt viscosity. Therefore, it can be widely used as a material for various molded products such as films, sheets, hollow molded containers, food trays, engineering plastics, and fibers.

[0092] The copolymerized polyester resin of the present invention may exhibit suppressed discoloration. Furthermore, the copolymerized polyester resin of the present invention may exhibit excellent biodegradability. Resins that exhibit excellent biodegradability and / or suppressed discoloration are particularly preferred as materials for various molded products such as films, sheets, hollow molded containers, food trays, engineering plastics, and fibers.

Claims

1. A copolymerized polyester resin that satisfies the following conditions (1) to (4). (1) The dicarboxylic acid component contains 20 to 80 mol% of adipic acid units and 20 to 80 mol% of terephthalic acid units per 100 mol%. (2) The diol component contains 1 to 20 mol% of units derived from ethylene glycol and 80 to 99 mol% of units derived from 1,4-butanediol in 100 mol% of the total diol component. (3) containing aluminum atoms and phosphorus atoms (4) Reduced viscosity of 1.0 dl / g or higher.

2. The copolymer polyester resin according to claim 1, wherein the copolymer polyester resin contains 10 to 100 ppm by mass of aluminum atoms and 20 to 250 ppm by mass of phosphorus atoms.

3. The copolymer polyester resin according to claim 1, wherein the color b value is 8 or less.

4. The copolymerized polyester resin according to claim 1, wherein the melting point is 50°C or higher.

5. A modified copolymer polyester resin according to any one of claims 1 to 4.

6. A copolymerized polyester resin composition comprising an additive in the copolymerized polyester resin and / or a modified product thereof according to any one of claims 1 to 4.

7. A molded article comprising the copolymerized polyester resin according to any one of claims 1 to 4.

8. A molded article comprising the modified substance described in claim 5.

9. A molded article comprising the copolymerized polyester resin composition described in claim 6.

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