JP6645755B2 - Polyester resin composition and molded article obtained using the same - Google Patents

Description

  The present invention relates to a polyester resin composition containing a polyester resin and a carbodiimide compound.

  Molded articles molded from polyester resins such as polyethylene terephthalate films (PET films) and polyethylene terephthalate bottles (PET bottles) are used in various packaging and industrial applications because of their excellent transparency and heat resistance. In order to suppress the hydrolysis of the polyester resin, a carbodiimide compound has been widely used as an additive of the polyester resin.

  As the carbodiimide compound used as an additive, a carbodiimide compound that has been compacted into a pellet has been used in order to enhance handling properties. However, the carbodiimide compound is inferior in dispersibility and affinity for the polyester resin and consequently incompatible with each other.Therefore, the polyester resin molded article obtained by adding the carbodiimide compound may have impaired transparency, The hydrolysis resistance could not be sufficiently increased. In the production of a PET film, the film may be broken at the time of stretching, or in the produced PET bottle, the carbodiimide compound may cause a gel or granular unmelted material.

In order to improve the compatibility of the carbodiimide compound, there is a method of preparing a masterbatch in which a carbodiimide compound is contained in a thermoplastic resin at a high concentration and adding the masterbatch at the time of melt-molding a polyester resin (for example, see Patent Document 1).
Also in the production of PET films and the like, masterbatch pellets containing a carbodiimide compound may be used in order to increase the durability against hydrolysis. The carbodiimide compound has been used in the form of pellets in order to enhance the handleability. However, the carbodiimide compound alone has poor dispersibility and affinity for polyethylene terephthalate, and as a result, it is incompatible with each other, impairing transparency and failing to sufficiently enhance hydrolysis resistance. In addition, a polyester film may be broken at the time of stretching, and a polyester bottle may have defects such as gels and bumps.

  To improve compatibility, a masterbatch composed of polyethylene terephthalate and carbodiimide is also being studied. However, the melting point of polyethylene terephthalate used as a matrix is 254 ° C, and the temperature is raised to about 260 ° C during melt processing of the masterbatch. Therefore, there is a concern that hydrolysis of the polyester may occur during the melt processing. Since the carbodiimide compound reacts with the end of the polyester after hydrolysis, the originally intended molded article after addition of the master batch could not sufficiently exhibit hydrolysis resistance.

  In order to reduce hydrolysis during melt processing, the melting point of the resin used as the matrix is also considered to be 220 ° C. or less, but since the carbodiimide concentration in the master batch obtained by the reaction increases, When added to a resin composition constituting a molded article such as a polyethylene terephthalate film or a polyethylene terephthalate bottle, a carbodiimide group reacts with a carboxyl group in the resin composition constituting the molded article, thereby increasing the viscosity of the resin composition. In some cases, the polyester film was broken at the time of stretching, and the polyester bottle sometimes became a defect such as gel or lumps.

JP 2013-49790 A

  The present invention solves the above-mentioned problems, and increases dispersibility and affinity for a polyester resin composition constituting a molded article, without deactivating a carbodiimide compound, and suppressing thickening. It is an object of the present invention to provide a polyester resin composition capable of producing a molded article having excellent quality.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention.
That is, the gist of the present invention is as follows.
(1) A polyester resin composition containing a polyester resin (A), a polyester resin (B) and a carbodiimide compound (C), wherein the polyester resin (B) has a melting point and a melting point of 220 ° C. or less, The resin (A) is an amorphous polyester resin having a glass transition temperature of 20 to 130 ° C., and the mass ratio (A / C) of the polyester resin (A) to the carbodiimide compound (C) is 10/90 to 85/15. And a polyester resin composition comprising 50 to 300 parts by mass of the polyester resin (B) based on 100 parts by mass of the total of the polyester resin (A) and the carbodiimide compound (C).
(2) The polyester resin (A) contains 0.05% of an organic sulfonate compound as a copolymer component.
The polyester resin composition according to (1), which contains 10 to 10 mol%.
(3) The polyester resin composition according to (1) or (2), wherein the polyester resin (B) contains 0.1 to 20 mol% of a metal salt of an organic sulfonic acid as a copolymerization component.
(4) A resin pellet containing the polyester resin composition according to any one of (1) to (3).
(5) A molded article characterized in that the resin pellet according to (4) is contained in a thermoplastic resin and melt-molded.

  The polyester resin composition of the present invention, because the carbodiimide compound is uniformly dispersed, excellent in dispersibility and affinity to the polyester resin composition constituting the molded article, and, without deactivating the carbodiimide compound, Thickening can be suppressed. For this reason, when the polyester resin composition of the present invention is used, it is possible to obtain a molded article having excellent quality and excellent hydrolysis resistance.

Hereinafter, the present invention will be described in detail.
The polyester resin composition of the present invention contains a polyester resin (A), a polyester resin (B) and a carbodiimide compound (C), and a resin pellet containing the resin composition is made of a thermoplastic resin such as a polyester resin. When a resin (hereinafter, sometimes referred to as a matrix resin) is molded, it can be added as a masterbatch of a carbodiimide compound to improve the hydrolysis resistance of the molded body.

<Polyester resin (A)>
The polyester resin (A) constituting the polyester resin composition of the present invention is mainly composed of a dicarboxylic acid component and a glycol component, and includes modified products thereof.

  Examples of the dicarboxylic acid component constituting the polyester resin (A) include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, and 3-tert-butylisophthalic acid Acids, aromatic dicarboxylic acids such as diphenic acid, oxalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dodecane diacid, eicosane diacid, saturated aliphatic dicarboxylic acids such as hydrogenated dimer acid, Unsaturated aliphatic dicarboxylic acids such as fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, dimer acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid , 1,2-cyclohexanedicarboxylic acid, 2,5-norbornene dica Alicyclic dicarboxylic acids such as boric acid and its anhydride, tetrahydrophthalic acid and its anhydride, trimellitic acid, benzophenonetetracarboxylic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, benzophenonetetracarboxylic anhydride , Trimesic acid, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimellitate), and polyvalent carboxylic acids such as 1,2,3,4-butanetetracarboxylic acid. These dicarboxylic acid components can be used alone or in combination of two or more.

  Among the dicarboxylic acids described above, it is preferable to use terephthalic acid or isophthalic acid as the dicarboxylic acid component, and the content of terephthalic acid or isophthalic acid in the dicarboxylic acid component is preferably 30 mol% or more. Alternatively, the total content of both is more preferably 50 mol% or more, and further preferably 70 mol% or more.

  Examples of the glycol component constituting the polyester resin (A) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, Aliphatic glycols such as 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and 2-ethyl-2-butylpropanediol Alicyclic glycols such as 1,4-cyclohexanedimethanol and 1,3-cyclobutanedimethanol; ether bond-containing glycols such as diethylene glycol, triethylene glycol, dipropylene glycol, polytetramethylene glycol, polyethylene glycol and polypropylene glycol; Alkylene oxide adducts of bisphenols (bisphenol A) such as 2,2-bis [4- (hydroxyethoxy) phenyl] propane and bisphenols (bisphenol S) such as bis [4- (hydroxyethoxy) phenyl] sulfone Alkylene oxide adducts and the like can also be used.

  Among the glycol components described above, ethylene glycol, 1,2-propanediol, neopentyl glycol, tricyclodecane dimethanol, isosorbide, and the like are preferable, and among them, ethylene glycol and neopentyl glycol are preferable. The content of one or both of them is more preferably at least 50 mol%, and further preferably at least 70 mol%.

  In the present invention, the polyester resin (A) is preferably such that the dicarboxylic acid component is composed of two or more dicarboxylic acids, or the glycol component is composed of two or more glycols. Both components may each be composed of two or more.

In the present invention, the polyester resin (A) preferably contains an organic sulfonate compound as a copolymer component. By using a polyester resin composition containing a copolymerized polyester resin containing an organic sulfonate compound as a copolymerization component, an increase in the viscosity of the resin composition constituting the molded article can be suppressed.
Examples of the organic sulfonate compound include a dicarboxylic acid having a sulfonate and a glycol having a sulfonate.

  The copolymerization amount of the organic sulfonate compound is preferably 0.05 to 10 mol% of the polyester resin (A), more preferably 0.15 to 7.5 mol%, and more preferably 0.25 to 7.5 mol%. More preferably, it is 5 mol%. When the content of the organic sulfonate compound is less than 0.05 mol%, the effect of suppressing the increase in viscosity of the molded product is not sufficient. On the other hand, when the content of the organic sulfonate compound exceeds 10 mol%, the resulting molding Hydrolysis resistance of the body may decrease.

  Raw materials used for copolymerizing the organic sulfonate compound with the polyester resin (A) include, for example, 5-sodium sulfoisophthalic acid, 5-sodium sulfoterephthalic acid, 5-potassium sulfoisophthalic acid, 5-potassium sulfoterephthalate Acid, 5-lithium sulfoisophthalic acid, 5-lithium sulfoterephthalic acid and the like. Also, sodium 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate, sodium 2,5-di (carbo-β-hydroxyethoxy) benzenesulfonate obtained by adding ethylene glycol or the like to the above dicarboxylic acid, 3 Diglycol esters such as potassium 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate, lithium 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate, and methanol or the like are added to the above dicarboxylic acid. Esters of dicarboxylic acids such as dimethyl 5-sodium sulfoisophthalate, dimethyl 5-sodium sulfoterephthalate, dimethyl 5-potassium sulfoisophthalate, and dimethyl 5-lithium sulfoisophthalate.

In addition to the above, metal salt compounds of glycols such as 2-sulfo-1,4-butanediol and 2,5-dimethyl-3-sulfo-2,5-hexanediol are exemplified.
Among these, 5-sodium sulfoisophthalic acid, dimethyl 5-sodium sulfoisophthalate, diglycol 5-sodium sulfoisophthalate, and the like are used as raw materials in terms of a good balance between the effect of suppressing viscosity increase and imparting hydrolysis resistance. It is particularly preferable to use 5-sodium sulfoisophthalic acid as a raw material from the viewpoint that suppression of increase in viscosity can be effectively provided.

The polyester resin (A) may be copolymerized with a hydroxycarboxylic acid, if necessary. Examples of hydroxycarboxylic acids include lactic acid, glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxyvaleric acid, and 3-hydroxybutyric acid. Hydroxycarboxylic acids such as valeric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 10-hydroxystearic acid, 4- (β-hydroxy) ethoxybenzoic acid, β-propiolactone, β -Butyrolactone, γ-butyrolactone, δ-valerolactone, and aliphatic lactones such as ε-caprolactone.
When the hydroxycarboxylic acid is copolymerized, the copolymerization amount is preferably 20 mol% or less of the total dicarboxylic acid component.

If the polyester resin (A) is in a small amount, it may be copolymerized with a trifunctional or higher functional carboxylic acid, a trifunctional or higher functional alcohol, a monocarboxylic acid, or a monoalcohol.
Examples of trifunctional or higher carboxylic acids include trimellitic acid, trimellitic anhydride, trimesic acid, pyromellitic acid, pyromellitic anhydride, benzophenonetetracarboxylic acid, benzophenonetetracarboxylic anhydride, ethylene glycol bis (anhydrotrimellitate). ), Glycerol tris (anhydrotrimellitate), 1,2,3,4-butanetetracarboxylic acid and the like. Examples of the trifunctional or higher alcohol include trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, α-methylglucose, mannitol, and sorbitol.

  When a trifunctional or higher functional carboxylic acid or a trifunctional or higher functional alcohol is copolymerized, the copolymerization amount is preferably 5 mol% or less, preferably 4 mol% or less, based on all dicarboxylic acid components and all glycol components. Is more preferable, and it is still more preferable that it is 3 mol% or less. When the copolymerization amount of a trifunctional or higher functional carboxylic acid or a trifunctional or higher functional alcohol exceeds 5 mol%, processability such as stretchability may be impaired when the obtained masterbatch is processed into a molded product. .

  Examples of the monocarboxylic acid copolymerized with the polyester resin (A) include benzoic acid, phenylacetic acid, lauric acid, palmitic acid, stearic acid, and oleic acid. Monoalcohols include cetyl alcohol, decyl alcohol, and lauryl alcohol. , Myristyl alcohol, octyl alcohol, stearyl alcohol and the like. When a monocarboxylic acid and a monoalcohol are copolymerized, the copolymerization amount is preferably 0.2 to 20 mol% with respect to all dicarboxylic acid components and all glycol components.

  The polyester resin (A) is an amorphous polyester resin and needs to have a glass transition temperature of 20 to 130 ° C., preferably a glass transition temperature of 30 to 120, and more preferably 40 to 120. Preferably it is 110 ° C. If the glass transition temperature is lower than 20 ° C., there is a concern that the resin composition obtained may be blocked when handled as a master batch, and the workability may be reduced. Further, when the glass transition temperature exceeds 130 ° C., not only the melt viscosity during melt-kneading is high but the workability is lowered, but also the kneading temperature becomes unnecessarily high due to shear heat, so that hydrolysis of the polyester resin occurs. There is a growing concern that the carbodiimide compound will be deactivated.

  The glass transition temperature of the polyester resin can be controlled in the above range by appropriately selecting monomers to be copolymerized.

  The number average molecular weight of the polyester resin (A) is preferably from 1,000 to 20,000, more preferably from 1,500 to 15,000, still more preferably from 2,000 to 10,000, and most preferably from 2,500 to 5,000. If the number average molecular weight of the polyester resin (A) is less than 1,000, the resulting polyester resin composition may have insufficient compatibility when used as a master batch, and may impair the transparency of the molded article. On the other hand, when the number average molecular weight of the polyester resin (A) exceeds 20,000, the melt viscosity at the time of mixing with the carbodiimide compound and melt-kneading becomes high, and not only the workability decreases, but also the kneading temperature becomes unnecessarily high due to shear heat generation. Is increased, hydrolysis of the polyester resin (A) occurs, and as described above, there is an increased concern that a part of the carbodiimide compound reacts. In addition, when the number average molecular weight is high, the ester group concentration in the polyester resin composition increases, so that the hydrolysis resistance tends to decrease.

  As a method of controlling the number average molecular weight of the polyester resin (A), a method of terminating the polymerization of a polyester melt at the time of polymerization with a predetermined viscosity, a method of producing a polyester having a high molecular weight, and then adding a depolymerizing agent to reduce the molecular weight. Control method, a method of adding a monoalcohol or a monocarboxylic acid, and the like. Among them, a method of terminating the polymerization at a predetermined viscosity is preferable.

  The polyester resin (A) in the present invention may contain a modified polyester resin. Examples of the modified polyester resin include a polyester polyurethane resin, a polyetherester, and an acryl-modified polyester resin. From the viewpoint of improving the hydrolysis resistance of the obtained molded product, a polyester polyurethane resin modified with an organic diisocyanate component is preferred. When a polyester polyurethane resin is used, the crosslinked density by the carbodiimide compound is increased, so that the obtained molded article has improved hydrolysis resistance as described above, but a film is produced using polyethylene terephthalate as a thermoplastic resin. When the film is formed, the compatibility with polyethylene terephthalate is reduced and the stretchability may be poor.

The polyester polyurethane resin used in the present invention can be obtained by adding an organic diisocyanate component to a polyester resin composed of the above components.
Known isocyanates can be used as the organic diisocyanate component. Specifically, 1,6-hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate, tetramethylene diisocyanate, 3,3 ′ -Dimethoxy-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-diisocyanate, 4,4'-diisocyanate diphenyl ether, 1,5 -Xylylene diisocyanate, 1,3-diisocyanatomethylcyclohexane, 1,4-diisocyanatomethylcyclohexane, 4,4'-diisocyanatocyclohexane, 4,4'-diisocy Sulfonates cyclohexyl methane include isocyanates such as isophorone diisocyanate. Among them, 1,6-hexamethylene diisocyanate is preferably used from the viewpoints of reactivity, weather resistance, and the like.
These organic diisocyanates may be used as a mixture of two or more.

  The content of the polyester resin component in the polyester polyurethane resin is preferably 40% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more. When the content of the polyester resin component in the polyester polyurethane resin is small, the effect of improving the hydrolysis resistance in the obtained molded product may not be sufficient.

  The polyester polyurethane resin can be manufactured by a known method. For example, there is a method in which a copolymerized polyester resin and an organic diisocyanate are solution-polymerized in a solvent. In the solution polymerization, after a previously obtained copolymerized polyester resin is dissolved in a general-purpose solvent such as toluene, an organic diisocyanate component and a urethanization catalyst are charged and reacted at 40 to 80 ° C. to obtain a polyester polyurethane resin. . In order to increase the reactivity of urethanization, dimethylolpropionic acid, dimethylolbutanoic acid, bis- (2-hydroxyethyl) propionic acid, and bis- (2-hydroxyethyl) butane are used for the copolymerized polyester resin. Preferably, an acid or the like is copolymerized. Examples of the urethane-forming catalyst include organic tin compounds such as dibutyltin dilaurate and tin octylate, and amine-based catalysts such as triethylenediamine.

<Polyester resin (B)>
The polyester resin (B) used in the present invention is mainly composed of a dicarboxylic acid component and a glycol component, and includes modified products thereof.

  Examples of the dicarboxylic acid component constituting the polyester resin (B) include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, and 3-tert-butyl isophthalic acid Acids, aromatic dicarboxylic acids such as diphenic acid, oxalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dodecane diacid, eicosane diacid, saturated aliphatic dicarboxylic acids such as hydrogenated dimer acid, Unsaturated aliphatic dicarboxylic acids such as fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, dimer acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid , 1,2-cyclohexanedicarboxylic acid, 2,5-norbornene dica Alicyclic dicarboxylic acids such as boric acid and its anhydride, tetrahydrophthalic acid and its anhydride, trimellitic acid, benzophenonetetracarboxylic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, benzophenonetetracarboxylic anhydride , Trimesic acid, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimellitate), and polyvalent carboxylic acids such as 1,2,3,4-butanetetracarboxylic acid. These polybasic acid components can be used alone or in combination of two or more.

  Among the above dicarboxylic acids, it is preferable to use terephthalic acid as the dicarboxylic acid component, and the content of terephthalic acid in the dicarboxylic acid component is preferably at least 50 mol%, more preferably at least 60 mol%. More preferably, it is 70 mol% or more.

And it is preferable to contain an organic sulfonate compound as a copolymer component similarly to the polyester resin (A). By using a polyester resin composition containing a polyester resin (B) containing an organic sulfonate compound as a copolymerization component, it is possible to suppress an increase in the viscosity of the resin composition constituting the molded article.
As the organic sulfonate compound, it is preferable to use the same one as the polyester resin (A) described above. The copolymerization amount of the organic sulfonate compound is preferably 0.1 to 20 mol%, more preferably 0.3 to 10 mol%, and more preferably 0.5 to 5 mol% of the polyester resin (B). % Is more preferable.

  Examples of the glycol component constituting the polyester resin (B) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, Aliphatic glycols such as 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and 2-ethyl-2-butylpropanediol Alicyclic glycols such as 1,4-cyclohexanedimethanol and 1,3-cyclobutanedimethanol, ether bond-containing glycols such as diethylene glycol, triethylene glycol, dipropylene glycol, polytetramethylene glycol, polyethylene glycol and polypropylene glycol; Glycerin, trimethylol ethane, trimethylol propane, trifunctional or higher alcohols such as pentaerythritol, and the like. Further, an alkylene oxide adduct of bisphenols (bisphenol A) such as 2,2-bis [4- (hydroxyethoxy) phenyl] propane and bisphenols (bisphenol such as bis [4- (hydroxyethoxy) phenyl] sulfone An alkylene oxide adduct of S) can also be used. These polyhydric alcohol components can be used alone or in combination of two or more.

  Among the above-mentioned glycol components, ethylene glycol, 1,4-butanediol and the like are preferable, and the content of either or both is preferably 50 mol% or more, and more preferably 60 mol% or more. Preferably, there is.

  Further, the polyester resin (B) may be copolymerized with a hydroxycarboxylic acid, if necessary. Examples of hydroxycarboxylic acids include lactic acid, glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxyvaleric acid, and 3-hydroxybutyric acid. Hydroxycarboxylic acids such as valeric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 10-hydroxystearic acid, 4- (β-hydroxy) ethoxybenzoic acid, β-propiolactone, β -Butyrolactone, γ-butyrolactone, δ-valerolactone, and aliphatic lactones such as ε-caprolactone. When a hydroxycarboxylic acid is copolymerized, the amount of the hydroxycarboxylic acid to be copolymerized is preferably 20 mol% or less based on all dicarboxylic acid components.

  The polyester resin (B) may be copolymerized with a monocarboxylic acid, a monoalcohol, a trifunctional or higher carboxylic acid, and a trifunctional or higher functional alcohol in a small amount. Examples of trifunctional or higher carboxylic acids include trimellitic acid, trimesic acid, and pyromellitic acid. Examples of trifunctional or higher functional alcohols include trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, α-methylglucose, Manitol and sorbitol. However, when a tribasic or higher polybasic acid is used, it is preferably 5 mol% or less, more preferably 4 mol% or less, and more preferably 3 mol% or less in the polybasic acid component of the copolymerized polyester resin. It is more preferred that there be. When the content of the trifunctional or higher functional carboxylic acid and the trifunctional or higher functional alcohol exceeds 5 mol%, the processability such as the stretchability when processing the molded body using the obtained master batch may be impaired.

  Monocarboxylic acids include benzoic acid, phenylacetic acid, lauric acid, palmitic acid, stearic acid, oleic acid, and the like.Monoalcohols include cetyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, octyl alcohol, stearyl alcohol. And the like. When a monocarboxylic acid and a monoalcohol are copolymerized, the amount of each copolymer is preferably from 0.2 to 20 mol% based on all dicarboxylic acid components and all glycol components.

The polyester resin (B), Ri crystalline polyester resin der having a melting point, it is necessary inter alia a melting point of 220 ° C. or less.

Polyester resin (B) has a melting point Ri der 220 ° C. or less, good Mashiku to be thirty to two hundred ten ° C., more preferably from 40 to 200 ° C., more preferably from fifty to one hundred ninety-five ° C.. When the melting point exceeds 220 ° C., the kneading temperature during melt mixing with the carbodiimide compound becomes too high, and hydrolysis of the polyester resin (B) occurs, and there is a high possibility that a part of the carbodiimide compound reacts. Further, when the melting point is lower than 30 ° C., there is a risk of blocking when handling the obtained master batch, and the workability may be reduced.

  The number average molecular weight of the polyester resin (B) is preferably from 3,000 to 20,000, more preferably from 4,000 to 18,000, and still more preferably from 5,000 to 16,000. When the number average molecular weight of the polyester resin (B) is less than 3,000, the molecular weight of the obtained polyester resin composition is low, and the resin composition cannot be obtained in the form of pellets. On the other hand, when the number average molecular weight of the polyester resin (B) exceeds 20,000, the melt viscosity at the time of mixing with the carbodiimide compound and melt-kneading becomes high, and not only the workability is lowered, but also the kneading temperature is increased more than necessary due to shear heat generation. Is increased, the polyester resin (B) is hydrolyzed, and as described above, there is a high possibility that a part of the carbodiimide compound reacts. In addition, when the number average molecular weight is high, the ester group concentration in the polyester resin composition increases, so that the hydrolysis resistance tends to decrease.

  As a method of controlling the number average molecular weight of the polyester resin (B), there are a method of terminating the polymerization of a polyester melt at the time of polymerization with a predetermined viscosity, a method of producing a polyester resin having a high molecular weight, and then adding a depolymerizing agent to the molecular weight. , A method of adding a monoalcohol or a monocarboxylic acid, and the like. Among them, a method of terminating the polymerization at a predetermined viscosity is preferable.

The production method for obtaining the polyester resin (A) and the polyester resin (B) used in the present invention includes known production methods such as a direct esterification method and a transesterification method. Examples of the direct esterification method include a method in which a necessary monomer material is injected into a reaction vessel, an esterification reaction is performed, and then a polycondensation reaction is performed. In the esterification reaction, the mixture is heated and melted at a temperature of 180 ° C. or more for 4 hours or more in a nitrogen atmosphere to cause a reaction. In the polycondensation reaction, the polycondensation reaction proceeds at a temperature of 220 to 280 ° C. under a reduced pressure of 130 Pa or less until a desired molecular weight is reached. In the esterification reaction and the polycondensation reaction, a catalyst may be used. Examples of the catalyst include titanium compounds such as tetrabutyl titanate; metal acetates such as zinc acetate, magnesium acetate and aluminum compounds; and organic tin compounds such as antimony trioxide, hydroxybutyltin oxide and tin octylate. The use amount of the catalyst is preferably 0.1 × 10 ^{−4 to} 100 × 10 ⁻⁴ mol per 1 mol of the acid component.

<Carbodiimide compound (C)>
The carbodiimide compound (C) constituting the polyester resin composition of the present invention is a compound having a carbodiimide group (-N = C = N-) in a molecule. According to the number of carbodiimide groups in the molecule, monocarbodiimide, Classified as polycarbodiimide.

  Examples of the monocarbodiimide having one carbodiimide group in the molecule include N, N'-di-2,6-diisopropylphenylcarbodiimide, N, N'-diphenylcarbodiimide, and N, N'-di-2,6. -Dimethylphenylcarbodiimide, N, N'-di-2,6-di-tert-butylphenylcarbodiimide, N-tolyl-N'-phenylcarbodiimide, N, N'-di-p-nitrophenylcarbodiimide, N, N '-Di-p-aminophenylcarbodiimide, N, N'-di-p-hydroxyphenylcarbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N, N'-di- o-ethylphenylcarbodiimide, N, N'-di-p-ethylphenylcarbodiimide N, N'-di-o-isopropylphenylcarbodiimide, N, N'-di-p-isopropylphenylcarbodiimide, N, N'-di-o-isobutylphenylcarbodiimide, N, N'-di-p-isobutylphenyl Carbodiimide, N, N'-di-2,6-diethylphenylcarbodiimide, N, N'-di-2-ethyl-6-isopropylphenylcarbodiimide, N, N'-di-2-isobutyl-6-isopropylphenylcarbodiimide N, N'-di-2,4,6-trimethylphenylcarbodiimide, N, N'-di-2,4,6-triisopropylphenylcarbodiimide, N, N'-di-2,4,6-tri Isobutylphenylcarbodiimide, di-β-naphthylcarbodiimide, N, N′-di-o-tolylcarbodiimide, N -Tolyl-N'-cyclohexylcarbodiimide, N, N'-di-p-tolylcarbodiimide, N, N'-benzylcarbodiimide, N-octadecyl-N'-tolylcarbodiimide, N-cyclohexyl-N'-tolylcarbodiimide, N Aromatic carbodiimides such as -benzyl-N'-tolylcarbodiimide, N, N'-dioctyldecylcarbodiimide, N, N'-di-cyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropyl Examples thereof include aliphatic and / or alicyclic monocarbodiimides such as carbodiimide and di-t-butylcarbodiimide.

  Examples of the polycarbodiimide having two or more carbodiimide groups in the same molecule include poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (4,4'-diphenylmethanecarbodiimide), and poly (methyl-methylcarbodiimide). Diisopropylphenylenecarbodiimide), poly (triisopropylphenylenecarbodiimide), poly (triylcarbodiimide), poly (diisopropylphenylenecarbodiimide), p-phenylene-bis-di-o-tolylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, ethylene -Bis-diphenylcarbodiimide, hexamethylene-bis-dicyclohexylcarbodiimide and the like.

  Polycarbodiimide can be produced by polymerizing the above-mentioned monocarbodiimide, or a commercially available product can be used. Commercially available polycarbodiimides include, for example, aromatic polycarbodiimides such as Starbucksol P manufactured by Rhinehemie, Starbucksol P-100 manufactured by Rhinehemy, and Starbucksol P-400 manufactured by Rhinehemie; LA- manufactured by Nisshinbo Chemical Inc. 1, aliphatic and / or alicyclic polycarbodiimides such as HMV-15CA manufactured by Nisshinbo Chemical Inc.

  As a method for producing polycarbodiimide, a method using an organic diisocyanate may be used in addition to the above method. As the organic diisocyanate, for example, various organic diisocyanates such as aromatic diisocyanate, aliphatic diisocyanate and alicyclic diisocyanate, and mixtures thereof can be used.

  Examples of the organic diisocyanate include 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and 2,4- Tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, methylcyclohexane diisocyanate, tetramethyl xylylene diisocyanate, 2,6-diisopropylphenyl isocyanate, 1,3,5-triisopropylbenzene-2,4-diiso Aneto, methylenebis (4,1-cyclohexylene) = can be mentioned diisocyanate. These may be used alone or in combination of two or more. Among these organic diisocyanates, dicyclohexylmethane-4,4-diisocyanate and methylenebis (4,1-cyclohexylene) = diisocyanate are preferred.

  In order to block the terminal of the carbodiimide compound and control the degree of polymerization, a terminal blocking agent such as monoisocyanate can be used. Examples of the monoisocyanate include phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, and naphthyl isocyanate. These may be used alone or in combination of two or more.

  As a terminal blocking agent for the carbodiimide compound, an active hydrogen compound that can react with isocyanate may be used in addition to the monoisocyanate. Examples of the active hydrogen compound include aliphatic, aromatic, and alicyclic compounds, alcohols such as methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, polyethylene glycol monomethyl ether, and polypropylene glycol monomethyl ether, and diethylamine. Secondary amines such as dicyclohexylamine, primary amines such as butylamine and cyclohexylamine, carboxylic acids such as succinic acid, benzoic acid and dichlorohexanecarboxylic acid, thiols and epoxy groups such as ethyl mercaptan, allyl mercaptan and thiophenol. And the like. These may be used alone or in combination of two or more.

In the present invention, the carbodiimide compound (C) preferably contains an isocyanate group at the terminal in order to increase the reactivity with the polyester resin. Therefore, even when the terminal isocyanate of polycarbodiimide is blocked by using the terminal blocking agent as described above, it is preferable that an isocyanate group is appropriately left at the terminal. Specifically, the content of the terminal isocyanate in the carbodiimide compound is preferably more than 0% by mass and less than 15% by mass, more preferably 0.1 to 12% by mass, and more preferably 0.5 to 10% by mass. % Is more preferable.
In a carbodiimide compound having a terminal isocyanate group content of 0% by mass, no reaction occurs between the terminal hydroxyl group of the polyester resin and the isocyanate group. Therefore, when this carbodiimide compound is used for the masterbatch, the compatibility and dispersibility with the matrix resin are reduced, so that the obtained molded product may be non-uniform and have reduced strength.
On the other hand, in a carbodiimide compound having a terminal isocyanate group of 15% by mass or more, the terminal hydroxyl group of the polyester resin (A) and the isocyanate group excessively react with each other to increase the crosslink density. In the case where is used, the dispersibility in the matrix resin may be reduced, and the stretchability or the like during the film formation may be reduced.

  In the present invention, the molecular weight of the polycarbodiimide compound is preferably from 1,000 to 10,000, more preferably from 1,000 to 9000, and even more preferably from 1,000 to 8,000. Since the polycarbodiimide compound having a molecular weight of 1,000 or less has a low carbodiimide group concentration, it must be added to the polyester resin composition in a large amount, and the compatibility with the matrix resin is reduced, and the obtained molded product has reduced strength. Sometimes. On the other hand, if the molecular weight of the polycarbodiimide compound exceeds 10,000, the compatibility and dispersibility with the matrix resin will be reduced, so that the resulting molded article will be non-uniform and the strength may be reduced.

  In the polycarbodiimide compound, the number of carbodiimide groups in the molecule is preferably 2 to 100, more preferably 2 to 80, and still more preferably 2 to 60. In the case of a monocarbodiimide having less than 2 carbodiimide groups, the effect of trapping a carboxyl group generated when a matrix resin having an ester bond such as a polyester resin is hydrolyzed is reduced, and the obtained molded article has a hydrolysis resistance. May drop. On the other hand, if the number of carbodiimide groups exceeds 100, the crosslink density of the polycarbodiimide compound may be too high, and the resulting polyester resin composition may be non-uniform or gelled. When a PET film or the like is formed as a master batch, the stretchability is reduced and the film may be broken.

The number of carbodiimide groups, which is the number of carbodiimides in a polycarbodiimide molecule, corresponds to (degree of polymerization −1) in the case of a polycarbodiimide obtained from a diisocyanate compound. For example, a polycarbodiimide obtained by connecting 21 diisocyanate compounds in a chain has a polymerization degree of 21, and the number of carbodiimide groups in the molecular chain is 20. Usually, polycarbodiimide is a mixture of molecules having various degrees of polymerization, and the number of carbodiimide groups is represented by an average value. The number of carbodiimide groups can be measured by ¹³ C-NMR, IR, GPC, titration or a combination thereof, and can be grasped as the number of carbodiimide groups. Note that peaks can be observed at 130 to 142 ppm in ¹³ C-NMR and at 2130 to 2140 cm ⁻¹ in IR.

<Polyester resin composition>
In the polyester resin composition of the present invention, the mass ratio (A / C) of the polyester resin (A) to the carbodiimide compound (C) needs to be 10/90 to 85/15, and is 20/80 to 80/80. / 20, more preferably 30/70 to 75/25. When the mass ratio of both is within the above range, the dispersibility of the carbodiimide compound in the polyester resin composition can be improved. When the content of the polyester resin (A) is less than 10, the content of the carbodiimide compound (C) becomes excessive, so that the dispersibility of the carbodiimide compound (C) becomes poor, and the obtained polyester resin composition is contained. A molded article formed by containing resin pellets is inferior in workability such as stretchability, and may have a reduced hydrolysis resistance. On the other hand, when the content of the polyester resin (A) exceeds 85, the content of the carbodiimide compound (C) becomes too small, so that sufficient hydrolysis resistance cannot be imparted to the molded article.

  And it is necessary to contain 50-300 mass parts of polyester resin (B) with respect to 100 mass parts of polyester resin (A) and carbodiimide compound (C) in total, especially 70-200 mass%. And more preferably 90 to 150% by mass. When the content of the polyester resin (B) is less than 50 parts by mass, the carbodiimide concentration in the resin composition increases, so that when the polyester resin (B) is added to a molded product such as a polyethylene terephthalate film or a polyethylene terephthalate bottle, a carbodiimide group is added. When the carboxyl group in the resin composition constituting the molded article reacts to increase the viscosity of the resin, the polyester film may be broken at the time of stretching, or a polyester bottle may have defects such as gels and lumps. When the content of the polyester resin (B) is more than 300 parts by mass, the effective carbodiimide group concentration in the resin composition becomes low, so that the polyester resin (B) increases in the polyester resin composition constituting the molded article. As a result, the resulting molded article may be non-uniform or the strength of the molded article may be reduced.

  The polyester resin composition of the present invention is obtained by melt-kneading a polyester resin (A) and a carbodiimide compound (C) to prepare a polyester resin composition (1) containing both of them in a predetermined amount. It is preferable to melt-knead 1) and the polyester resin (B) to prepare a polyester resin composition (2) containing respective components in a predetermined amount.

  The polyester resin composition of the present invention may contain additives as long as the effects of the present invention are not impaired. Additives include crosslinking agents, antioxidants, viscosity modifiers, extenders, dyes, pigments, UV absorbers, void formers, lubricants, radical scavengers, heat stabilizers, flame retardants, inhibitors, and anti-blocking agents Agents, surface active agents, slip aids, gloss improvers, decomposition accelerators, viscosity modifiers, dispersion stabilizers and the like.

<Resin pellets>
The resin pellet of the present invention contains the above-described polyester resin composition of the present invention. After melt-kneading using the twin-screw kneading extruder or the like, it can be manufactured by drawing in a strand shape from a die of a die, cooling, and pelletizing.
The kneading temperature in the case of performing the melt kneading is preferably 220 ° C. or lower. Even if the kneading temperature is set to 220 ° C. or lower, the resin temperature may exceed 220 ° C. due to shear heating during melt kneading, so that the resin temperature does not exceed 220 ° C. It is preferable to perform the melt kneading by controlling the screw rotation speed and the discharge amount. Further, by using a polyester resin (A) having a low melting point or a low glass transition temperature, it is possible to reduce shear heat generation during melt kneading.
The obtained resin pellets can be used as a master batch. The masterbatch may be subjected to a heat treatment such as drying if necessary.

<Thermoplastic resin>
The above resin pellets can be formed into a molded article by mixing with various thermoplastic resins (matrix resins) such as polyester resin and then melt-molding. Since the resin pellets of the present invention use the polyester resins (A) and (B), they can be used particularly preferably for polyester matrix resins such as polyethylene terephthalate. However, the present invention is not limited to this, and can be used in a wide range as long as there is no problem such as compatibility.
The acid value of the matrix resin is preferably 10 mgKOH / g or less, more preferably 8 mgKOH / g or less, and even more preferably 6 mgKOH / g or less. When the acid value of the matrix resin exceeds 10 mgKOH / g, the carbodiimide group in the master batch to be mixed reacts, and the effective carbodiimide group concentration contributing to the hydrolysis resistance decreases, and the expected hydrolysis resistance is reduced. May not be obtained.

<Molded body>
The molded article of the present invention is obtained by melt-molding a thermoplastic resin used as a matrix resin with resin pellets contained therein. The carbodiimide compound contained in the resin pellets has excellent hydrolysis resistance.
Such an effect is particularly effectively exhibited when the matrix resin is a polyester resin. In order to further improve the hydrolysis resistance, the amount of the resin pellets to be added depends on the ester group concentration (a equivalent / ton) of the polyester resin of the matrix resin and the ester group concentration (b) of the polyester resin (A) constituting the master batch. The ratio (c / (a + b)) of the carbodiimide compound (B) to the carbodiimide group concentration (c equivalent / ton) with respect to the total of (equivalents / ton) is preferably 0.1 to 1.5, and 0.1 to 1.5. It is more preferably from 2 to 1.3, further preferably from 0.3 to 1.1, and most preferably from 0.5 to 1.0. If the ratio (c / (a + b)) is less than 0.1, the expected hydrolysis resistance cannot be obtained, and if it exceeds 1.5, the carbodiimide group in the molded article excessively reacts and the thermal stability decreases. Or gelation may occur, and when the film is formed, the stretchability may be reduced or the film may be broken.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by these examples.

The measuring methods used for evaluating the polyester resins obtained in the examples and comparative examples are as follows.
1. Evaluation method (1) Number average molecular weight of polyester resin GPC analysis using a liquid sending unit (“LC-10ADvp type” manufactured by Shimadzu Corporation) and an ultraviolet-visible spectrophotometer (“SPD-6AV type” manufactured by Shimadzu Corporation) Determined by The analysis conditions were as follows: the detection wavelength was 254 nm, tetrahydrofuran was used as the solvent, and the polystyrene conversion was used.

(2) Composition of polyester resin ¹ H-NMR measurement was performed using an NMR measurement device (“JNM-LA400” manufactured by JEOL Ltd.) to determine the composition of each copolymer component. Note that deuterated trifluoroacetic acid was used as a measurement solvent.

(3) Glass transition temperature (Tg), melting point (Tm) of polyester resin
According to JIS-K 7121, a glass transition temperature (Tg) was obtained from a chart in which the temperature was raised from 20 ° C. to 300 ° C. at 10 ° C./min using an input-compensated differential scanning calorimeter (Diamond DSC manufactured by Perkin Elmer). ) And melting point (Tm).

(4) Compatibility between resin pellets and polyester resin (matrix resin) The appearance of the films obtained in Examples and Comparative Examples was visually observed. The judgment was made based on the following evaluation criteria.
〇: Excellent in transparency.
Δ: Although transparent, the dispersion of the mixed master batch is non-uniform and has a feeling of fluctuation.
×: Opaque or turbid.

(5) Stretchability In Examples and Comparative Examples, the stretchability was evaluated by the operability in producing a film.
〇: A film having a uniform thickness can be obtained without any operational problems.
Δ: Stretching is possible, but the film thickness and the like of the obtained film are not uniform.
×: Stretching is not possible due to breakage or the like.

(6) Hydrolysis resistance The obtained film was treated under the conditions of 85 ° C and 85% RH for 2000 hours. For the films before and after the treatment, the tensile strength at break was measured, the tensile strength retention was calculated from the following equation, and the hydrolysis resistance was judged according to the following criteria. The evaluation result is preferably ◎ or ○, particularly preferably ◎.
The film was cut into a strip having a width of 10 mm and a length of 150 mm and used as a measurement sample. The tensile strength at break was measured at 23 ° C. × 50% RH at a tensile speed of 10 mm / min.
Tensile strength retention (%) = (Tensile rupture strength of film after treatment) / (Tensile rupture strength of film before treatment) × 100
A: Tensile strength retention is 95% or more.
〇: The tensile strength retention is 80% or more and less than 95%.
Δ: Tensile strength retention is 70% or more and less than 80%.
X: Tensile strength retention is less than 70%.

(7) Change in viscosity The obtained film was dissolved in an equal mass mixture of phenol and ethane tetrachloride as a solvent, and the intrinsic viscosity (η) was measured under the conditions of a sample concentration of 0.5% by mass and a temperature of 20 ° C. .
Since the intrinsic viscosity of the polyester resin used as the matrix resin at the time of film production was 0.60, the viscosity change rate was calculated from the following formula in comparison with this, and the viscosity change rate was evaluated according to the following criteria. The evaluation result is preferably ◎ or ○, particularly preferably ◎.
Viscosity change rate (%) = η / 0.60 × 100
◎: less than 110% ：: 110% or more, less than 115% Δ: 115% or more, less than 120% ×: 120% or more

2. Raw material (1) Carbodiimide compound (C)
C1: Aromatic polycarbodiimide (“Stabacsol P” manufactured by Rhine Chemie, poly (1,3,5-triisopropylbenzene) carbodiimide, number average molecular weight: about 700)
C2: alicyclic polycarbodiimide ("LA-1" manufactured by Nisshinbo Chemical Inc., average degree of polymerization 15, terminal isocyanate group)
C3: Aromatic monopolycarbodiimide (“Stabaczol I” manufactured by Rhine Chemie, N, N′-di-2,6-diisopropylphenylcarbodiimide)
C4: alicyclic polycarbodiimide ("HV-15CA" manufactured by Nisshinbo Industries, average degree of polymerization 15, no terminal isocyanate group)

(2) Compounds other than carbodiimide compounds (epoxy compounds)
X: EGMA (ethylene-glycidyl methacrylate copolymer) -g (graft) -AS (acrylonitrile styrene) copolymer (“MODIPA A4400” manufactured by NOF Corporation, EGMA / AS = 70/30 (mass ratio), E / GMA = 85/15 (mass ratio)

(3) Polyester resin used as matrix resin Polyethylene terephthalate resin manufactured by Unitika (Intrinsic viscosity: 0.60, acid value: 2 mgKOH / g)

<Preparation of polyester resin (A)>
Preparation Example 1
50 mol% of terephthalic acid, 48 mol% of isophthalic acid, 2 mol% of 5-sodium sulfoisophthalic acid, 75 mol% of ethylene glycol, 60 mol% of neopentyl glycol and 0.1 g of tetrabutyl titanate as a polymerization catalyst were charged into a reactor. The system was replaced with nitrogen. Then, while stirring these raw materials at 1000 rpm, the reactor was heated at 245 ° C. and melted. After the temperature in the reactor reached 245 ° C., the esterification reaction was allowed to proceed for 0.5 hour. After a lapse of 0.5 hours, the temperature in the system was raised to 240 ° C., and the pressure in the system was reduced. After the inside of the system reached a high vacuum (pressure: 0.1 to ^10-5 Pa), a polymerization reaction was further performed for 0.4 hours to obtain a polyester resin (A1). Table 1 shows the results.

Preparation Examples 2 to 11
Polyester resins (A2) to (A11) were obtained in the same manner as in Preparation Example 1, except that the type of monomer used, its composition, and the polymerization reaction time were changed as shown in Table 1.

<Preparation of polyester polyurethane resin>
Preparation Example 12
The polyester polyurethane resin (A12) was obtained by adding an organic diisocyanate component to the polyester resin (A2) obtained in Preparation Example 2. Specifically, the same amount of toluene was charged to the polyester resin (A2), and the resin was dissolved at 100 ° C. Thereafter, the temperature was increased to 130 ° C., and 30% by weight of the total amount of the polyester resin and toluene was distilled to dehydrate the reaction system. Thereafter, the inside of the system was cooled to 60 ° C., and 40% by weight of methyl ethyl ketone and 9% by weight of dimethylolbutanoic acid were charged based on the amount of the polyester resin, followed by stirring at 60 ° C. for 30 minutes. Thereafter, 6% by weight of 1,6-hexamethylene diisocyanate was charged, and the mixture was stirred at 60 ° C. for 30 minutes. Subsequently, dibutyltin dilaurate was added as a catalyst, the temperature was raised to 80 ° C., and the reaction was performed. The concentration was adjusted to 30% to obtain the desired polyester polyurethane (A12).

  Table 1 shows the charged composition, polymerization reaction time, and final composition of the polyester resins (A1) to (A12) obtained in Preparation Examples 1 to 12.

<Preparation of polyester resin (B)>
Preparation Example 13
80 mol% of terephthalic acid, 18 mol% of isophthalic acid, 2 mol% of 5-sodium sulfoisophthalic acid, 135 mol% of ethylene glycol and 0.1 g of tetrabutyl titanate as a polymerization catalyst were charged into a reactor, and the system was replaced with nitrogen. . Then, while stirring these raw materials at 1000 rpm, the reactor was heated at 245 ° C. and melted. After the temperature in the reactor reached 245 ° C., the esterification reaction was allowed to proceed for 0.5 hour. After a lapse of 0.5 hours, the temperature in the system was raised to 240 ° C., and the pressure in the system was reduced. After the inside of the system reached a high vacuum (pressure: 0.1 to ^10-5 Pa), a polymerization reaction was further performed for 0.5 hour to obtain a polyester resin (B1). Table 1 shows the results.

Preparation Examples 14 to 23
Polyester resins (B2) to (B11) were obtained in the same manner as in Preparation Example 13, except that the type of monomer used, its composition, and the polymerization reaction time were changed as shown in Table 1.

  Table 1 shows the charged composition, polymerization reaction time, and final composition of the polyester resins (B1) to (B11) obtained in Preparation Examples 13 to 23.

In addition, the abbreviation in Table 1 shows the following, respectively.
TPA: terephthalic acid IPA: isophthalic acid SEA: sebacic acid ADA: adipic acid SIPA: 5-sodium sulfoisophthalic acid EG: ethylene glycol PG: propanediol BD: 1,4-butanediol NPG: neopentyl glycol TCD: tricyclode Candimethanol ISB: isosorbide HDI: 1,6-hexamethylene diisocyanate

Example 1
After uniformly mixing 30 parts by mass of the polyester resin (A) and 70 parts by mass of the carbodiimide compound (C1), a total charged amount of 3 kg was measured using a loss-in-weight continuous continuous quantitative supply device (CE-W-1 type manufactured by Kubota Corporation). And supplied to the main supply port of a twin-screw extruder having a screw diameter of 26 mm (Model TEM26SS manufactured by Toshiba Machine Co., Ltd.) to perform melt kneading. On the way, deaeration was performed at a degree of vent pressure reduction of -0.099 MPa (gauge pressure), the strand was taken out from a die, cooled and solidified in a water tank, cut with a pelletizer, and then a polyester resin composition (1) pellet was obtained. Melt kneading was performed under the conditions of a barrel temperature setting of an extruder of 150 ° C., a discharge rate of 20 kg / h, and a screw rotation speed of 300 rpm.
After sufficiently drying the polyester resin composition (1) pellets obtained by the above-mentioned melt-kneading, the polyester resin (B) becomes 150 parts by mass with respect to 100 parts by mass of the polyester resin composition pellets (1). After a uniform mixing, a total of 3 kg was fed into a twin-screw extruder with a screw diameter of 26 mm (Toshiba Machine TEM26SS) using a loss-in-weight continuous continuous feeder (Kubota CE-W-1). And melted and kneaded. On the way, deaeration was performed at a degree of vent pressure reduction of -0.099 MPa (gauge pressure), the strand was taken out of a die in a strand shape, cooled and solidified in a water tank, cut with a pelletizer, and then a polyester resin composition (2) pellet was obtained. Melt kneading was performed under the conditions of a barrel temperature setting of an extruder of 200 ° C., a discharge rate of 20 kg / h, and a screw rotation speed of 300 rpm.
The matrix resin (polyester resin) and the obtained polyester resin composition (2) pellets were sufficiently dried and then mixed. At this time, the polyester resin composition (2) pellets were mixed so as to be 1% by mass, kneaded at a temperature of 280 ° C., and extruded from a T-die. This was closely attached to a cooling drum adjusted to a temperature of 35 ° C. by an electrostatic application method and rapidly cooled to obtain a sheet having a thickness of 260 μm. The sheet was stretched three times in the machine direction at 90 ° C., stretched 4.0 times in the transverse direction at 120 ° C., and subsequently heat-treated at 230 ° C. for 5 seconds to obtain a polyester film having a thickness of 25 μm. .

Examples 2 to 35, Comparative Examples 1 to 5
Example 1 was the same as Example 1 except that the kind of the polyester resin (A) and the kind and the compounding ratio of the carbodiimide compound (C) and the kind and the compounding ratio of the polyester resin (B) were changed as shown in Tables 2 and 3. By performing the same operation, pellets of the polyester resin composition (2) of Examples 2 to 35 and Comparative Examples 1 to 5 were obtained.
Then, in the same manner as in Example 1, a polyester film having a thickness of 25 μm was obtained using the obtained pellets of the polyester resin composition (2) and the matrix resin (polyester resin).

  The polyester films obtained in Examples 1 to 35 and Comparative Examples 1 to 5 were evaluated for compatibility, change in viscosity, stretchability, and hydrolysis resistance. The results are shown in Tables 2 and 3.

  The polyester resin compositions [polyester resin composition pellets (2)] obtained in Examples 1 to 35 are excellent in handling as a masterbatch, and the polyester film obtained using the same has compatibility, change in viscosity, and stretching. It was excellent in both evaluation of the property and hydrolysis resistance.

  In Comparative Example 1, since the content of the polyester resin (A) in the polyester resin composition (1) was less than the predetermined amount, the carbodiimide compound (C) was not uniformly dispersed, and thus a molded article was obtained. In this case, the stretchability was poor, and the obtained molded article was also poor in hydrolysis resistance.

  In Comparative Example 2, since the content of the polyester resin (A) in the polyester resin composition (1) was larger than the predetermined amount and the content of the carbodiimide compound (C) was small, the obtained molded article was resistant to hydrolysis. It was inferior.

  In Comparative Example 3, since the content of the polyester resin (B) in the polyester resin composition (2) was less than the predetermined amount, the rate of change in viscosity was large, and the degree of viscosity increase when obtaining a molded article was large. .

  In Comparative Example 4, since the content of the polyester resin (B) in the polyester resin composition (2) was larger than the predetermined amount, the stretchability in obtaining a molded article was poor.

In Comparative Example 5, since no carbodiimide compound was used in the polyester resin composition, stretchability in obtaining a molded article was poor, and the obtained molded article was poor in hydrolysis resistance.

Claims (5)

A polyester resin composition containing a polyester resin (A), a polyester resin (B) and a carbodiimide compound (C), wherein the polyester resin (A) has a glass transition temperature of 2
A non-crystalline polyester resin having a melting point of 0 to 130 ° C., a melting point of 220 ° C. or less, and a mass ratio (A / C) of the polyester resin (A) and the carbodiimide compound (C). ) Is 10/90 to 85/15, and the polyester resin (B) is contained in an amount of 50 to 300 parts by mass with respect to a total of 100 parts by mass of the polyester resin (A) and the carbodiimide compound (C). Polyester resin composition. The polyester resin (A) contains an organic sulfonate compound as a copolymer component in an amount of 0.05 to 10%.
The polyester resin composition according to claim 1, wherein the composition contains mol%. The polyester resin (B) contains 0.1 parts of an organic sulfonic acid metal salt compound as a copolymerization component.
3. The polyester resin composition according to claim 1, wherein the content of the polyester resin is from about 20 mol%. A resin pellet comprising the polyester resin composition according to claim 1. A molded article obtained by melting and molding the resin pellet according to claim 4 in a thermoplastic resin.