JP2017002253A - Polyester resin composition and molded body obtained by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin composition capable of providing a molded body having enhanced compatibility or process stretchability and excellent in hydrolysis resistance and impact resistance.SOLUTION: There is provided a polyester resin composition containing a copolymer polyester resin (A) and a carbodiimide compound (B), where acid value of the copolymer polyester resin (A) is 10 to 70 mgKOH/g and mass ratio of the polymer polyester resin (A) and the carbodiimide compound (B) (A/B) is 10/90 to 85/15.SELECTED DRAWING: None

Description

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

  Molded articles formed from a polyester resin such as a polyethylene terephthalate film (PET film) and a polyethylene terephthalate bottle (PET bottle) are excellent in transparency and heat resistance, and thus are used in various packaging and industrial applications. In order to suppress hydrolysis of the polyester resin, carbodiimide compounds have been widely used as additives for polyester resins.

  The carbodiimide compound used as an additive has been used which has been pressed into a pellet to improve handling. However, since the carbodiimide compound is inferior in dispersibility and affinity to the polyester resin and is not compatible as a result, the polyester resin molded product obtained by adding the carbodiimide compound may lose transparency. The hydrolysis resistance could not be sufficiently improved. In the production of a PET film, the film may be broken during processing and stretching, and in the produced PET bottle, the carbodiimide compound may cause gels or granular unmelted materials.

In order to improve the compatibility of the carbodiimide compound, there is a method in which a master batch in which a carbodiimide compound is contained in a thermoplastic resin at a high concentration is prepared and added at the time of melt molding of a polyester resin (for example, patent document). 1).
In the production of PET films and the like, master batch pellets containing a carbodiimide compound may be used in order to increase the durability against hydrolysis.

JP 2013-49790 A

In the production of PET films and the like, in order to further improve the compatibility of the carbodiimide compound, it has been studied to use polyethylene terephthalate as a thermoplastic resin constituting the masterbatch. However, since polyethylene terephthalate has a melting point of about 250 ° C., it needs to be melt-processed at a temperature of 260 ° C. or higher when preparing a masterbatch using it, and may be hydrolyzed during this melt-processing. It was. As a result, a part of the carbodiimide compound may be consumed by reacting with the end of the polyethylene terephthalate after hydrolysis. Therefore, even if a master batch containing polyethylene terephthalate as a thermoplastic resin is added and molded, the content of the reactive carbodiimide compound is reduced and the reactivity is lowered. Hydrolyzability may not be improved sufficiently.
Moreover, when the masterbatch which made the polyester resin contain the carbodiimide compound was used, the obtained molded object may be inferior to impact resistance.

  An object of this invention is to provide the polyester resin composition which can obtain the molded object which was improved in compatibility and work stretchability, and was excellent in hydrolysis resistance and impact resistance.

The inventor of the present invention has reached the present invention as a result of intensive studies in order to solve the above problems.
That is, the gist of the present invention is as follows.
(1) A polyester resin composition containing a copolyester resin (A) and a carbodiimide compound (B), wherein the copolyester resin (A) has an acid value of 10 to 70 mgKOH / g, A polyester resin composition, wherein the mass ratio (A / B) of (A) to the carbodiimide compound (B) is 10/90 to 85/15.
(2) The polyester according to (1), wherein the copolyester resin (A) is a crystalline polyester resin having a melting point of 220 ° C. or lower and / or an amorphous polyester resin having a glass transition temperature of 50 ° C. or higher. Resin composition.
(3) A resin pellet comprising the polyester resin composition described in (1) or (2) above.
(4) A method for producing resin pellets as described in (3) above, wherein the copolymer polyester resin (A) and the carbodiimide compound (B) are melt-kneaded at a temperature of 230 ° C. or lower. Pellet manufacturing method.
(5) A molded article obtained by melt-kneading and molding the resin pellets of the above (3) and a thermoplastic resin.

  According to the present invention, a polyester resin composition containing a carbodiimide compound in a copolyester resin can be obtained without reducing the reactivity. Resin pellets obtained from the polyester resin composition of the present invention have improved dispersibility and affinity of the carbodiimide compound in the copolyester resin, improved compatibility, and as a master batch of the carbodiimide compound, polyester resin, etc. It can be used by adding to the thermoplastic resin, and a molded article with sufficiently improved hydrolysis resistance and impact resistance can be formed.

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

<Copolymerized polyester resin (A)>
The copolymerized 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 those modified products.

  The dicarboxylic acid component constituting the copolymerized polyester resin (A) is not particularly limited, and examples thereof include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, and 5-sodium sulfoisophthalic acid. Acids, aromatic dicarboxylic acids such as 3-tert-butylisophthalic acid and diphenic acid; oxalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, aicosane diacid, hydrogenated dimer acid Saturated aliphatic dicarboxylic acids such as fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, dimer acid and the like; 1,4-cyclohexanedicarboxylic acid 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, , 5-norbornene dicarboxylic acids and their anhydrides, alicyclic dicarboxylic acids such as tetrahydrophthalic acid and its anhydride.

  Among the dicarboxylic acids described above, terephthalic acid is preferably used as the dicarboxylic acid component, and the content of terephthalic acid in the dicarboxylic acid component is preferably 30 to 99.9 mol%, and 45 to 99.9 mol. % Is more preferable, and 60 to 99.9 mol% is still more preferable.

  The glycol component constituting the copolyester resin (A) is not particularly limited, and examples thereof include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and 2-methyl. -1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2- Aliphatic glycols such as butylpropanediol; Alicyclic glycols such as 1,4-cyclohexanedimethanol and 1,3-cyclobutanedimethanol; Diethylene glycol, triethylene glycol, dipropylene glycol, polytetramethylene glycol, polyethylene glycol, polypropylene A such as glycol Glycol containing glycol; alkylene oxide adducts of bisphenols (bisphenol A) such as 2,2-bis [4- (hydroxyethoxy) phenyl] propane and bisphenols such as bis [4- (hydroxyethoxy) phenyl] sulfone An alkylene oxide adduct of bisphenol S (bisphenol S) can also be used.

  In the present invention, the copolyester resin (A) must have the dicarboxylic acid component composed of two or more dicarboxylic acids or the glycol component composed of two or more glycols. Each of the glycol components may be composed of two or more.

The copolymerized polyester resin (A) may be copolymerized with a hydroxycarboxylic acid as necessary. 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, 3-hydroxy 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 And aliphatic lactones such as -butyrolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone.
When copolymerizing hydroxycarboxylic acid, the copolymerization amount is preferably 20 mol% or less of the total dicarboxylic acid component.

Further, the copolymerized polyester resin (A) may be copolymerized with a trifunctional or higher functional carboxylic acid, a trifunctional or higher functional alcohol, a monocarboxylic acid, or a monoalcohol as long as the amount is small.
Trifunctional or higher carboxylic acids include trimellitic acid, trimellitic anhydride, trimesic acid, pyromellitic acid, pyromellitic anhydride, benzophenone tetracarboxylic acid, benzophenone tetracarboxylic anhydride, ethylene glycol bis (anhydro trimellitate) ), Glycerol tris (anhydro trimellitate), 1,2,3,4-butanetetracarboxylic acid and the like. Examples of the tri- or higher functional alcohol include trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, α-methylglucose, mannitol, and sorbitol.
When copolymerizing a trifunctional or higher functional carboxylic acid or a trifunctional or higher functional alcohol, the copolymerization amount is preferably 5 mol% or less, and preferably 4 mol% or less, based on the total dicarboxylic acid component or total glycol component, respectively. It is 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 processing into a molded body using the obtained master batch. .

  Examples of the monocarboxylic acid copolymerized with the copolymerized polyester resin (A) include benzoic acid, phenylacetic acid, lauric acid, palmitic acid, stearic acid, oleic acid and the like, and monoalcohols include cetyl alcohol, decyl alcohol, Examples include lauryl alcohol, myristyl alcohol, octyl alcohol, stearyl alcohol, and the like. When copolymerizing monocarboxylic acid and monoalcohol, the copolymerization amount is preferably 0.2 to 20 mol% with respect to the total dicarboxylic acid component and the total glycol component, respectively.

The acid value of the copolyester resin (A) needs to be 10 to 70 mgKOH / g, preferably 13 to 65 mgKOH / g, and more preferably 15 to 60 mgKOH / g. When the acid value of the copolyester resin (A) is in the above range, a polyester resin composition having a certain degree of crosslinked structure with the carbodiimide compound (B) described later can be obtained, and molding using this as a master batch The body has excellent impact resistance as well as hydrolysis resistance and processability. When the acid value of the copolymerized polyester resin (A) is less than 10 mgKOH / g, the molded article has poor impact resistance. When the acid value exceeds 70 mgKOH / g, the molded article has hydrolysis resistance and processability. It will be inferior.
Examples of the method for controlling the acid value of the copolyester resin (A) include a method of adding a depolymerizer and a method of adding an acid anhydride after producing a polyester resin having a high molecular weight. In the present invention, since both the acid value of the copolyester resin (A) and the number average molecular weight described later can be controlled in a well-balanced manner, a depolymerizer is added after producing a polyester resin having a high molecular weight, A method of controlling the valence and number average molecular weight is preferred.
As the depolymerizing agent, isophthalic acid, adipic acid, sebacic acid and the like are preferable, and as the acid anhydride, pyromellitic anhydride and the like are preferable.

  The copolyester resin (A) is preferably a crystalline polyester resin having a melting point of 220 ° C. or lower, an amorphous polyester resin having a glass transition temperature of 50 ° C. or higher, or a mixture thereof. The amorphous property of the copolyester resin (A) is such that the heat of crystal fusion corresponding to the melting point, measured using a differential scanning calorimeter at a heating rate of 10 ° C./min, is less than 0.25 cal / g. It is defined as a thing.

  The crystalline polyester resin preferably has a melting point of 220 ° C. or lower, more preferably 30 to 220 ° C., further preferably 40 to 200 ° C., and most preferably 50 to 190 ° C. When the melting point exceeds 220 ° C., the kneading temperature at the time of melt mixing with the carbodiimide compound becomes too high, the copolymerized polyester resin (A) is hydrolyzed, and there is a concern that a part of the carbodiimide compound reacts. Further, when the melting point is less than 30 ° C., there is a concern such as blocking when handling the obtained master batch, and workability may be lowered. Note that the crystalline polyester resin having a melting point higher than 220 ° C. does not hinder the use of the crystalline polyester resin because the expected effect can be expressed by devising the processing conditions. For example, a crystalline polyester resin having a melting point exceeding 220 ° C. can be kneaded using shearing heat generation even if the kneading temperature is less than 220 ° C., and the kneading temperature exceeds 230 ° C. Even if there is, the carbodiimide compound (B) is introduced from the upstream side of the extruder, the crystalline polyester resin having a melting point exceeding 220 ° C. is supplied on the downstream side of the extruder, and melt mixing is performed in a short time. It is possible to prepare a resin composition.

  The amorphous polyester resin preferably has a glass transition temperature of 50 ° C or higher, more preferably 55 ° C or higher, further preferably 60 ° C or higher, and most preferably 65 ° C or higher. When the glass transition temperature is less than 50 ° C., there is a concern such as blocking when handling the obtained master batch, and workability may be lowered. The glass transition temperature of the polyester resin can be controlled within the above range by appropriately selecting a monomer to be copolymerized.

  In the present invention, the use of a crystalline polyester resin rather than an amorphous polyester resin as the copolyester resin (A) reduces problems such as blocking when handling a masterbatch, and improves workability. Is particularly preferable.

The number average molecular weight of the copolyester resin (A) is preferably 1,000 to 20,000, more preferably 1,500 to 15,000, and preferably 2,000 to 10,000. More preferred is 2,500 to 5,000. When the number average molecular weight of the copolymerized polyester resin (A) is less than 1,000, the resulting polyester resin composition lacks compatibility when used as a masterbatch and impairs the transparency of the molded article. There is. On the other hand, when the number average molecular weight of the copolyester resin (A) exceeds 20,000, the melt viscosity at the time of mixing and melt-kneading with the carbodiimide compound increases, and not only the workability decreases, but also necessary due to shearing heat generation. When the kneading temperature is increased as described above, the copolymerized polyester resin (A) is hydrolyzed, and as described above, a concern that a part of the carbodiimide compound reacts increases. Moreover, since ester group density | concentration in a polyester resin composition will increase when a number average molecular weight is high, there exists a tendency for hydrolysis resistance to fall.
As a method for controlling the number average molecular weight of the copolymerized polyester resin (A), a method of terminating the polymerization of the polyester melt during polymerization at a predetermined viscosity, a depolymerizer is added after producing a polyester resin having a high molecular weight. And a method of controlling the molecular weight and a method of adding a monoalcohol or a monocarboxylic acid.

In the present invention, examples of the method for producing the copolyester resin (A) include 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 raw material is injected into a reaction vessel, an esterification reaction is performed, and then a polycondensation reaction is performed. In the esterification reaction, the reaction is performed by heating and melting at a temperature of 180 ° C. or higher for 4 hours or longer in a nitrogen atmosphere. In the polycondensation reaction, the polycondensation reaction proceeds under a reduced pressure of 130 Pa or less until a desired molecular weight is reached at a temperature of 220 to 280 ° C. A catalyst may be used in the esterification reaction and polycondensation reaction. 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 amount of the catalyst, the acid component per mol, preferably in a 0.1 × ^{10 -4} ~100 × ¹⁰ -4 mol.

  The copolyester resin (A) constituting the polyester resin composition of the present invention may contain a modified polyester resin. Examples of the modified polyester resin include a polyester polyurethane resin, a polyether ester, and an acrylic modified polyester resin. From the viewpoint of improving the hydrolysis resistance of the resulting molded article, a polyester polyurethane resin modified with an organic diisocyanate component is preferred. When polyester polyurethane resin is used, the crosslink density due to the carbodiimide compound increases, so that the resulting molded article has improved hydrolysis resistance as described above, but a film is produced using polyethylene terephthalate as the thermoplastic resin. When the film is formed, the compatibility with polyethylene terephthalate is lowered and the stretchability may be inferior.

The polyester polyurethane resin used in the present invention is obtained by adding an organic diisocyanate component to a polyester resin composed of the above components.
A known isocyanate 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-diisocyanate methylcyclohexane, 1,4-diisocyanate methylcyclohexane, 4,4'-diisocyanate cyclohexane, 4,4'-diisocyanate Sulfonates cyclohexyl methane include isocyanates such as isophorone diisocyanate. Of these, 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 polyester resin component content in the polyester polyurethane resin is preferably 40% by mass or more, more preferably 60% by mass or more, and further preferably 80% by mass or more. When there is little content of the polyester resin component in a polyester polyurethane resin, the hydrolysis resistance improvement effect may not be enough in the molded object obtained.

  The polyester polyurethane resin can be produced by a known method. For example, a solution polymerization method of a copolymerized polyester resin and an organic diisocyanate in a solvent can be used. In solution polymerization, a copolyester resin obtained in advance is dissolved in a general-purpose solvent such as toluene, and then an organic diisocyanate component and a urethanization catalyst are charged and reacted at 40 to 80 ° C. to obtain a polyester polyurethane resin. . Further, in order to increase the reactivity of urethanization, dimethylolpropionic acid, dimethylolbutanoic acid, bis- (2-hydroxyethyl) propionic acid, bis- (2-hydroxyethyl) butane is used with respect to the copolyester resin. It is preferable to copolymerize an acid or the like. Examples of the urethanization catalyst include organotin compounds such as dibutyltin dilaurate and tin octylate, and amine-based compounds such as triethylenediamine.

<Carbodiimide compound (B)>
The carbodiimide compound (B) constituting the polyester resin composition of the present invention is a compound having a carbodiimide group (—N═C═N—) in the molecule, and depending on 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 monocarbodiimide such as benzyl-N'-tolylcarbodiimide, N, N'-dioctyldecylcarbodiimide, N, N'-di-cyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropyl Aliphatic / or alicyclic monocarbodiimides such as carbodiimide and di-t-butylcarbodiimide are exemplified.

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- 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, and a commercially available product can also be used. Examples of commercially available products of polycarbodiimide include aromatic polycarbodiimides such as Stavacsol P manufactured by Rheinhemy, Stavacsol P-100 manufactured by Rheinhemy, Stavacsol P-400 manufactured by Rheinhemy, and LA- manufactured by Nisshinbo Chemical Co., Ltd. 1. An aliphatic / or alicyclic polycarbodiimide such as HMV-15CA manufactured by Nisshinbo Chemical Co., Ltd. can be mentioned.

  As a method for producing polycarbodiimide, in addition to the above method, a method for producing using organic diisocyanate may be mentioned. As the organic diisocyanate, 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, 2,4- Tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene 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 individually by 1 type and may be used in combination of 2 or more type. Among these organic diisocyanates, dicyclohexylmethane-4,4-diisocyanate and methylenebis (4,1-cyclohexylene) = diisocyanate are preferable.

  In order to seal 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 individually by 1 type and may be used in combination of 2 or more type.

  In addition to the monoisocyanate, an active hydrogen compound capable of reacting with isocyanate may be used as a terminal blocker for the carbodiimide compound. Active hydrogen compounds include aliphatic, aromatic and alicyclic compounds such as methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether and other alcohols, 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 such as ethyl mercaptan, allyl mercaptan, thiophenol, and epoxy groups And the like. These may be used individually by 1 type and may be used in combination of 2 or more type.

In the present invention, the carbodiimide compound (B) preferably contains an isocyanate group at the end in order to increase the reactivity with the polyester resin. For this reason, it is preferable to leave an isocyanate group appropriately at the terminal even when the terminal isocyanate of the polycarbodiimide is sealed using the terminal blocking agent as described above. 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 the carbodiimide compound in which the content of the terminal isocyanate group is 0% by mass, the reaction between the terminal hydroxyl group of the copolymerized polyester resin (A) and the isocyanate group does not occur. Therefore, when this carbodiimide compound is used for the master batch, the compatibility with the matrix resin and the dispersibility are lowered, so that the obtained molded product is uneven and the strength may be lowered.
On the other hand, in a carbodiimide compound having a terminal isocyanate group of 15% by mass or more, the terminal hydroxyl group and the isocyanate group of the copolyester resin (A) are excessively reacted to increase the crosslinking density. When a carbodiimide compound is used, the dispersibility into the matrix resin may decrease, and the stretchability may decrease during film formation.

  In the present invention, the molecular weight of the polycarbodiimide compound is preferably 1,000 to 10,000, preferably 1,000 to 9,000, and more preferably 1,000 to 8,000. . A polycarbodiimide compound having a molecular weight of 1,000 or less has a low carbodiimide group concentration, so it must be added in a large amount to the polyester resin composition, resulting in a decrease in compatibility with the matrix resin and a decrease in workability. The molded product obtained may be degraded in hydrolysis resistance, impact resistance and the like. On the other hand, when the molecular weight of the polycarbodiimide compound exceeds 10,000, the compatibility with the matrix resin and the dispersibility are lowered, so that the obtained molded product becomes non-uniform and the strength may be lowered.

In the polycarbodiimide compound, the number of carbodiimide groups in the molecule is preferably 2 to 100, more preferably 2 to 80, and even more preferably 2 to 60.
In the case of monocarbodiimide having less than 2 carbodiimide groups, the effect of trapping carboxyl groups generated when a matrix resin having an ester bond such as a polyester resin is hydrolyzed is reduced. Impact resistance may be reduced.
On the other hand, when the number of carbodiimide groups in the polycarbodiimide compound exceeds 100, the crosslinking density may increase excessively, and the resulting polyester resin composition may become non-uniform or gel. When this polyester resin composition is used as a master batch to form a PET film or the like, stretchability may be reduced and the film may break. In addition, the obtained molded product may have a reduced impact resistance.
The number of carbodiimide groups, which is the number of carbodiimides in the polycarbodiimide molecule, corresponds to (polymerization degree -1) if it is a polycarbodiimide obtained from a diisocyanate compound. For example, the degree of polymerization of polycarbodiimide obtained by connecting 21 diisocyanate compounds in a chain is 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 method or a combination thereof, and can be grasped as the number of carbodiimide groups. It is possible to observe a peak at 130 to 142 ppm in ¹³ C-NMR and 2130 to 2140 cm ⁻¹ in IR.

<Polyester resin composition>
In the polyester resin composition of the present invention, the mass ratio (A / B) of the copolymerized polyester resin (A) and the carbodiimide compound (B) needs to be 10/90 to 85/15, and 20/80 It is preferably ˜80 / 20, more preferably 30/70 to 75/25. When the content of the copolymerized polyester resin (A) is less than 10% by mass, the molded product formed by including a master batch containing the obtained polyester resin composition has insufficient compatibility and transparency. It will be damaged. On the other hand, when the content of the copolymerized polyester resin (A) exceeds 85% by mass, sufficient hydrolysis resistance cannot be imparted to the molded body.

  The polyester resin composition of the present invention may contain an additive as long as the effects of the invention are not impaired. Additives include cross-linking agents, antioxidants, viscosity modifiers, extenders, dyes, pigments, UV absorbers, void forming agents, lubricants, radical scavengers, thermal stabilizers, flame retardants, inhibitors, and antiblocking agents. Agents, surfactants, slip aids, gloss improvers, degradation accelerators, viscosity modifiers, dispersion stabilizers, and the like.

  The polyester resin composition of the present invention can be produced by mixing a copolymer polyester resin (A) and a carbodiimide compound (B). The method is not particularly limited. For example, a method of melt kneading using a twin screw kneading extruder or the like is the simplest and most efficient.

<Resin pellets>
The resin pellets of the present invention can be produced by melt-kneading using the above-described biaxial kneader-extruder or the like, then taking them into a strand shape from a die die, cooling, and pelletizing.
The kneading temperature for melt kneading is preferably 230 ° C. or lower. Even if the kneading temperature is set to 230 ° C. or lower, the resin temperature may exceed 230 ° C. due to shear heat generation during melt kneading, so while monitoring the resin temperature so that the resin temperature does not exceed 230 ° C., It is preferable to perform melt-kneading by controlling the screw rotation speed and the discharge amount. Further, by using a copolymer polyester resin (A) having a low melting point or glass transition temperature, it is possible to reduce shearing heat generation during melt-kneading.
The obtained resin pellet can be used as a master batch. The master batch may be subjected to heat treatment such as drying as necessary.

<Thermoplastic resin>
The said resin pellet can be made into a molded object by melt-molding, after mixing with various thermoplastic resins (matrix resin), such as a polyester resin. In addition, since the resin pellet of the present invention uses the copolyester resin (A), it can be particularly suitably used for polyester matrix resins such as polyethylene terephthalate, polybutylene terephthalate, polycyclohexane terephthalate, and the like. However, it is not particularly limited to polyester matrix resins, and can be used in a wide range as long as no problem occurs 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 further 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 to reduce the effective carbodiimide group concentration contributing to hydrolysis resistance, and the expected hydrolysis resistance. It may not be obtained.

<Molded body>
The molded body of the present invention is obtained by melt-kneading and molding a thermoplastic resin used as a matrix resin and resin pellets, and has excellent hydrolysis resistance and impact resistance due to the carbodiimide compound contained in the resin pellets. It will have.
Such an effect is effectively exhibited especially when the matrix resin is a polyester resin. In order to further improve hydrolysis resistance and impact resistance, the amount of resin pellets added depends on the ester group concentration (a equivalent / ton) of the polyester resin of the matrix resin and the copolymer 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 the ester group concentration (b equivalent / ton) is 0.1 to 1.5. It is preferably 0.2 to 1.3, more preferably 0.3 to 1.1, and most preferably 0.5 to 1.0. If the ratio (c / (a + b)) is less than 0.1, the expected hydrolysis resistance and impact resistance cannot be obtained. If the ratio (c / (a + b)) exceeds 1.5, the carbodiimide group in the molded body is excessively reacted, In some cases, the stability may be reduced, or gelation may occur. 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 to these examples.

  The measuring method used for evaluation of the copolyester resin (A) used in Examples and Comparative Examples is as follows.

1. Evaluation Method (1) Number Average Molecular Weight of Copolyester Resin (A) Liquid-feeding unit ("LC-10ADvp type" manufactured by Shimadzu Corporation) and UV-visible spectrophotometer ("SPD-6AV type" manufactured by Shimadzu Corporation)) Was obtained by GPC analysis. The analysis conditions were a detection wavelength of 254 nm, tetrahydrofuran was used as a solvent, and the measurement was performed in terms of polystyrene.

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

(3) Glass transition temperature (Tg) and melting point (Tm) of the copolyester resin (A)
In accordance with JIS-K 7121, a glass transition temperature (Tg) was calculated from a chart heated at 10 ° C./min from 20 ° C. to 300 ° C. using an input-compensated differential scanning calorimeter (“Diamond DSC” manufactured by PerkinElmer). ), And the melting point (Tm) was read.

(4) Acid value of copolymerized polyester resin (A) 150 mg of copolymerized polyester resin (A) was precisely weighed into a test tube, 5 mL of benzyl alcohol was added and dissolved by heating, and the mixture was transferred to a Meyer flask containing 10 mL of chloroform. The used test tube was heated and washed with 5 mL of benzyl alcohol, and the washing solution was also transferred to a Meyer flask. The solution of the obtained copolyester resin (A) was titrated with 0.1N KOH benzyl alcohol solution using phenol red as an indicator. From the difference from the titration of the blank test, the copolyester resin (A) The acid value (mgKOH / g) was determined.

(5) Compatibility of resin pellets and polyester resin (matrix resin) The appearance of the films obtained in Examples and Comparative Examples was visually observed, and the compatibility was evaluated according to the following criteria.
◯: Excellent transparency.
(Triangle | delta): Although it is transparent, the dispersion | distribution of the mixed masterbatch is non-uniform | heterogenous and has a feeling of fluctuation.
X: Opaque or cloudy.

(6) Extensibility In Examples and Comparative Examples, extensibility was evaluated by operability when producing films.
○: There is no problem in operation.
(Triangle | delta): Although it can extend | stretch, a film thickness etc. are nonuniform.
X: It cannot extend | stretch with a fracture | rupture etc.

(7) Hydrolysis resistance The obtained film was treated for 2000 hours under the condition of 85 ° C. × 85% RH. About the film before and behind a process, the tensile breaking strength was measured, the tensile strength retention was computed from the following formula, and the hydrolysis resistance was evaluated by the following reference | standard. The evaluation result is preferably ◎ or ○, particularly preferably ◎.
The film was cut into a strip shape having a width of 10 mm and a length of 150 mm, and used as a measurement sample. The tensile breaking strength was measured under the conditions of 23 ° C. × 50% RH and a tensile speed of 10 mm / min.
Tensile strength retention (%) = (Tensile rupture strength of the film after treatment) / (Tensile rupture strength of the film before treatment) × 100
A: Tensile strength retention is 95% or more.
A: Tensile strength retention is 90% or more and less than 95%.
Δ: Tensile strength retention is 70% or more and less than 90%.
X: Tensile strength retention is less than 70%.

(8) Impact resistance The test pieces obtained in the examples and comparative examples are installed in a DuPont type drop impact tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the weight is dropped under conditions of a drop weight of 300 g and a height of 300 mm. The test piece after dropping was visually observed, and those that were not cracked or cracked were regarded as “pass”. Five test pieces were tested, and the impact resistance was evaluated by the number of passed test pieces.
A: All 5 pieces passed.
A: Four pieces were passed.
Δ: Three pieces passed.
X: The number of the test pieces which passed was two or less.

2. Raw material (1) Carbodiimide compound (B)
B1: Aromatic polycarbodiimide (Rhein Chemie's “Stabbackzol P”, poly (1,3,5-triisopropylbenzene) carbodiimide, number average molecular weight of about 700)
B2: Alicyclic polycarbodiimide ("LA-1" manufactured by Nisshinbo Chemical Co., Ltd., poly (4,4'-dicyclohexylmethanecarbodiimide), average polymerization degree 15, with terminal isocyanate group)
B3: Aromatic monopolycarbodiimide (Rhein Chemie's “Stabbackzol I”, N, N′-di-2,6-diisopropylphenylcarbodiimide)

(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) Preparation Preparation Example 1 of Copolymerized Polyester Resin (A)
70 mol% terephthalic acid, 30 mol% sebacic acid, 135 mol% ethylene glycol and a polymerization catalyst, tetrabutyl titanate in an amount of 3 x ^10-4 mol per mol of acid component were charged into the reactor, and the system was filled with nitrogen Replaced with And while stirring these raw materials at 1000 rpm, the reactor was heated to 245 ° C. and melted. After the reactor temperature reached 245 ° C., the esterification reaction was allowed to proceed for 0.5 hour. After 0.5 hours, the temperature in the system was set 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.
After the completion of the polymerization reaction, the system is brought to atmospheric pressure with nitrogen gas, the temperature of the system is lowered, and when the temperature reaches 220 ° C., 1.0 mol% of sebacic acid as a depolymerization component is further added and stirred at 220 ° C. for 2 hours. Thus, a copolyester resin (A1) was obtained.

Preparation Examples 2-8, 10-11, 13-14
The copolymerized polyester resins (A2) to (A8) and (A10) were prepared in the same manner as in Preparation Example 1 except that the types and amounts of the monomer components and depolymerization components used and the polymerization reaction time were changed as shown in Table 1. To (A11) and (A13) to (A14) were obtained. In addition, about the preparation example in which the depolymerization component is not described in Table 1, what completed the polymerization reaction was made into copolyester resin.

Preparation Example 9
In Preparation Example 1, after the polymerization reaction was completed, the system was brought to atmospheric pressure with nitrogen gas, the temperature of the system was lowered, and when the temperature reached 200 ° C., an acid anhydride (pyromellitic dianhydride) was added as an additional component. The mixture was stirred at 170 ° C. for 2 hours to obtain a copolyester resin (A9).

Preparation Example 12 (Preparation of polyester polyurethane resin)
A polyester polyurethane resin (A12) was obtained by adding organic diisocyanate (1,6-hexamethylene diisocyanate) as a modifying component to the copolyester resin (A1) obtained in Preparation Example 1.
Specifically, the same amount of toluene was charged into the copolymerized polyester resin (A1), and the resin was dissolved at 100 ° C. Thereafter, the temperature was raised to 130 ° C., 30% by mass of the total amount of the copolyester resin (A1) and toluene was distilled, and the reaction system was dehydrated. Thereafter, the system was cooled to 60 ° C., 40% by mass of methyl ethyl ketone and 9% by mass of dimethylolbutanoic acid were added to the copolymerized polyester resin (A1), and the mixture was stirred at 60 ° C. for 30 minutes. Then, 6 mass% of 1,6-hexamethylene diisocyanate was added, 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., the reaction was performed, and then the solvent was removed. Thus, a polyester polyurethane resin (A12) was obtained.

  Tables 1 and 2 show the monomer charge composition, polymerization reaction time, and characteristics of the copolyester resins obtained in Preparation Examples 1 to 14.

In addition, the abbreviation in Tables 1-2 shows the following each.
TPA: terephthalic acid IPA: isophthalic acid SEA: sebacic acid ADA: adipic acid EG: ethylene glycol PG: propanediol BD: 1,4-butanediol TCD: tricyclodecane dimethanol ISB: isosorbide PMDA: pyromellitic dianhydride PMA: pyromellitic acid HDI: 1,6-hexamethylene diisocyanate

Example 1
After uniformly mixing 35 parts by mass of the copolymerized polyester resin (A1) and 65 parts by mass of the carbodiimide compound (B1), a total charge of 3 kg is supplied with a loss-in-weight continuous quantitative supply device (CE-W-1 type manufactured by Kubota Corporation). It was used for melt kneading by supplying it to the main supply port of a twin screw extruder (TEM26SS type manufactured by Toshiba Machine Co., Ltd.) having a screw diameter of 26 mm. In the middle, deaeration was performed at a vent pressure reduction of -0.099 MPa (gauge pressure), the strands were taken out in a strand shape, cooled and solidified in a water tank, and cut with a pelletizer, to obtain resin pellets made of a polyester resin composition. The melt kneading was performed under the conditions of an extruder barrel temperature setting of 200 ° C., a discharge rate of 20 kg / h, and a screw rotation speed of 300 rpm.

(Film forming)
After the obtained resin pellets are sufficiently dried, the resin pellet content is 1 mass with respect to polyethylene terephthalate resin (unitika Co., Ltd. PET resin, intrinsic viscosity 0.60, acid value 2 mgKOH / g) as a matrix resin. %, And then kneaded at a temperature of 280 ° C. and extruded from a T-die. The sheet was brought into close contact with a cooling drum whose temperature was adjusted to 35 ° C. by an electrostatic application method and rapidly cooled to obtain a sheet having a thickness of 260 μm. The sheet was stretched 3 times in the machine direction at 90 ° C., and stretched 4.0 times in the transverse direction at 120 ° C., followed by heat treatment at 230 ° C. for 5 seconds to form a polyethylene terephthalate having a thickness of 25 μm. A film was obtained.

(Specimen molding)
Similarly to the film molding, after mixing so that the content of the resin pellets is 1% by mass with respect to the polyethylene terephthalate resin as the matrix resin, using a FANUC injection molding machine (S2000i-100B type), A test piece (50 mm × 90 mm × 2 mm) was molded under the conditions of a cylinder temperature of 280 ° C., a mold temperature of 30 ° C., an injection speed of 100 mm / second, and a cooling time of 20 seconds.

Examples 2-20, Comparative Examples 1-6
Except having changed the kind and mass ratio of the copolymerization polyester resin and carbodiimide compound to be used as shown in Table 3, the same operation as in Example 1 was performed to obtain resin pellets made of the polyester resin composition.
A film and a test piece were molded in the same manner as in Example 1 using the obtained resin pellets.

  The films obtained in Examples 1 to 20 and Comparative Examples 1 to 6 were evaluated for compatibility, stretchability, and hydrolysis resistance. The test pieces were evaluated for impact resistance. Shown in

  The polyester resin compositions obtained in Examples 1 to 20 are excellent in handling as a masterbatch, those mixed with a matrix resin are excellent in stretchability at the time of molding, and the obtained molded products are compatible and resistant. It was excellent in hydrolyzability and impact resistance.

In Comparative Example 1, since the carbodiimide compound was added directly to the matrix resin without adding the resin pellet of the polyester resin composition containing the copolyester resin and the carbodiimide compound, the compatibility and the stretchability were inferior. It was.
In Comparative Example 2, since the acid value of the copolyester resin (A) was lower than the amount specified in the present invention, the obtained molded article was inferior in impact resistance. In Comparative Example 3, since the acid value of the copolyester resin (A) is higher than the amount specified in the present invention, the stretchability at the time of molding is low, and the obtained molded product is inferior in hydrolysis resistance. It was.
In Comparative Example 4, the content of the copolyester resin (A) in the polyester resin composition was less than the amount specified in the present invention, so that the compatibility was poor. In Comparative Example 5, since the content of the carbodiimide compound (B) in the polyester resin composition was less than the amount specified in the present invention, the hydrolysis resistance of the molded product could not be sufficiently improved.
In Comparative Example 6, since a resin composition containing a carbodiimide compound was not used, the hydrolysis resistance of the molded article was low, and the stretchability was inferior.

Claims (5)

  A polyester resin composition comprising a copolyester resin (A) and a carbodiimide compound (B), wherein the copolyester resin (A) has an acid value of 10 to 70 mgKOH / g, and the copolyester resin (A) And a carbodiimide compound (B) having a mass ratio (A / B) of 10/90 to 85/15.   The polyester resin composition according to claim 1, wherein the copolyester resin (A) is a crystalline polyester resin having a melting point of 220 ° C or lower and / or an amorphous polyester resin having a glass transition temperature of 50 ° C or higher. .   A resin pellet comprising the polyester resin composition according to claim 1.   It is a method for manufacturing the resin pellet of Claim 3, Comprising: Copolyester resin (A) and a carbodiimide compound (B) are melt-kneaded at the temperature of 230 degrees C or less, The manufacturing method of the resin pellet characterized by the above-mentioned. . A molded article obtained by melt-kneading and molding the resin pellets of claim 3 and a thermoplastic resin.