JP2016153452A - Thermoplastic resin composition excellent in barrier property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition capable of achieving both of high barrier property and high flexibility, good in injection moldability and extrusion processability and excellent in melting retention stability of the resin composition.SOLUTION: There is provided a thermoplastic resin composition containing (A) a polyester block copolymer having melt flow rate (ASTM D1238) of 0.1 to 10 g/10 min. (210°C, load 2160 g), (B) an ethylene vinyl alcohol copolymer and (C) a modified ethylene-vinyl-based monomer copolymer having at least one kind of a carboxylic acid group, a carboxylic acid anhydride group and a hydroxyl group with the following mass ratios: (A)/(B)=10/90 to 90/10; [(A)+(B)]/(C)=100/0.1 to 100/10.SELECTED DRAWING: None

Description

  TECHNICAL FIELD The present invention relates to a thermoplastic resin composition having improved barrier properties and improved compatibility of a compounded resin composition of a hydrophobic thermoplastic resin and a hydrophilic thermoplastic resin. Specifically, when a film, a film, or the like is formed In particular, the present invention relates to a thermoplastic resin composition having excellent barrier properties against gases, aromatic organic compounds and the like, and excellent in flexibility, moldability, stretchability, melt stability, and the like.

  In general, an ethylene-vinyl alcohol copolymer resin (hereinafter referred to as “EVOH resin”) is a thermoplastic resin that has excellent gas barrier properties such as oxygen impermeability and is easy to be molded. It is used in many applications such as container materials and pipes. However, EVOH resin is poor in flexibility, inferior in impact resistance and inferior in moisture resistance, etc. Therefore, hydrophobic resin such as flexible polyolefin is added to EVOH resin to increase the stretchability and flexibility of the molded product. Attempts have been made to improve (see, for example, Patent Documents 1 and 2). However, such a resin composition is not sufficiently compatible with EVOH resin and polyolefin, so the physical properties and appearance do not appear with good reproducibility, the moldability is poor, and the gas barrier property is also lower than that of EVOH resin. It ’s not good enough.

  On the other hand, since the polyester block copolymer has flexibility, it is widely used as a substitute for vulcanized rubber, is easy to mold, has excellent low and high temperature characteristics, but has no oxygen permeability. The gas barrier property such as the property is insufficient, and the barrier property against the aromatic organic compound such as the styrene monomer is remarkably inferior, and improvement is desired.

  Then, although mixing | blending of EVOH resin and a polyester block copolymer is considered, both compatibility is worse than the case of EVOH resin and polyolefin. As a resin composition with improved compatibility, a method using a polyester block copolymer modified with an unsaturated carboxylic acid or a derivative thereof has been proposed (Patent Document 3). However, in the method of Patent Document 3, the stability of the extruded strand is poor and the productivity is poor, the flexibility is insufficient, and there is room for improvement in the melt stability and the like.

Japanese Patent Laid-Open No. 5-98084 JP 2000-219792 A JP 2004-2791 A

  The present invention has been made in order to solve the above-mentioned problems, compensates for the disadvantages of both EVOH resin and polyester block copolymer, and can achieve both high barrier properties and high flexibility. It is possible to provide a thermoplastic resin composition that has good moldability and extrudability and is excellent in melt residence stability of the resin composition.

The present inventors diligently studied and came to propose the following invention. That is, the present invention is as follows.
[1] Polyester block copolymer (A), ethylene vinyl alcohol copolymer (B) having a melt flow rate (ASTM D1238) of 0.1 to 10 g / 10 min (210 ° C., load 2160 g), and carboxylic acid A thermoplastic resin composition comprising a modified ethylene-vinyl monomer copolymer (C) having at least one of a group, a carboxylic acid anhydride group, and a hydroxyl group in the following mass ratio: .
(A) / (B) = 10/90 to 90/10
[(A) + (B)] / (C) = 100 / 0.1-100 / 10

[2] The thermoplastic resin composition according to [1], wherein the polyester block copolymer (A) contains a poly (alkylene oxide) glycol segment as a soft segment component.
[3] The thermoplastic resin composition according to [2], wherein the content of the poly (alkylene oxide) glycol segment in the polyester block copolymer (A) is 10 to 80% by mass.
[4] The thermoplastic resin composition according to any one of [1] to [3], wherein the polyester block copolymer (A) is a modified polyester block copolymer obtained by modification with an epoxy compound.
[5] The modified ethylene-vinyl monomer copolymer (C) is an ethylene-vinyl monomer copolymer obtained by copolymerizing an unsaturated carboxylic acid, and a partially saponified ethylene-vinyl acetate copolymer. The thermoplastic resin composition according to any one of [1] to [4], which is at least one of the coalescence.
[6] Graft polymer in which the modified ethylene-vinyl monomer copolymer (C) has an ethylene-acrylic acid ester-maleic anhydride copolymer as a main chain and an acrylonitrile-styrene copolymer as a side chain. The thermoplastic resin composition according to any one of [1] to [4].
[7] The thermoplastic resin composition according to any one of [1] to [6], wherein the polyester block copolymer (A) is dispersed in an average dispersed particle diameter of 2 μm or less in the thermoplastic resin composition.

  The thermoplastic resin composition of the present invention can achieve both high barrier properties and high flexibility, is excellent in injection moldability and extrusion processability, and is excellent in melt residence stability of the resin composition. It is a resin composition.

[Polyester block copolymer (A)]
The polyester block copolymer (A) used in the present invention is a polyester block copolymer having a hard segment component and a soft segment component. The hard segment component is preferably a polyester formed from an aromatic dicarboxylic acid or an ester-forming derivative thereof and an aliphatic diol or an ester-forming derivative thereof. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, and diphenoxyethanedicarboxylic acid. Acid, 5-sulfoisophthalic acid, and the like, and ester-forming derivatives thereof. If the amount is small, in addition to the aromatic dicarboxylic acid, an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid may be used in combination. The aliphatic diol is preferably a diol having a molecular weight of 300 or less. Examples of such diols include aliphatic diols such as 1,4-butanediol, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, and decamethylene glycol. If the amount is small, in addition to the aliphatic diol, alicyclic diols such as 1,1-cyclohexanedimethanol, 1,4-dicyclohexanedimethanol, tricyclodecane dimethanol, xylylene glycol, bis (p-hydroxy) ) Diphenyl, bis (p-hydroxyphenyl) propane, 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxy) phenyl] sulfone, 1,1-bis [4 An aromatic diol such as-(2-hydroxyethoxy) phenyl] cyclohexane may be used in combination. It may be a copolyester in which two or more dicarboxylic acid components and / or diol components are used in combination.
As a component constituting the polyester of the hard segment component, those comprising a butylene terephthalate unit or a butylene naphthalate unit are preferable from the viewpoint of physical properties, moldability, and cost performance. In the case of naphthalate units, 2,6 are preferable. These units are preferably 60 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more of the polyester of the hard segment component. Hereinafter, unless otherwise specified, butylene terephthalate refers to a unit composed of 1,4-butanediol and terephthalic acid, and butylene naphthalate refers to a unit composed of 1,4-butanediol and 2,6-naphthalenedicarboxylic acid. Point to.

The soft segment component of the polyester block copolymer (A) used in the present invention is preferably at least one of aliphatic polyether, aliphatic polyester, and aliphatic polycarbonate.
Aliphatic polyether components include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, copolymers of ethylene oxide and propylene oxide, poly (propylene oxide) And poly (alkylene oxide) glycols such as ethylene oxide addition polymer of glycol and a copolymer of ethylene oxide and tetrahydrofuran.
Examples of the aliphatic polyester component include polycaprolactone, polyenanthlactone, polycaprylolactone, polybutylene adipate, ε-caprolactone, enanthlactone, and caprylolactone.
The aliphatic polycarbonate is composed of an aliphatic diol residue having 2 to 12 carbon atoms and a carbonate bond. Examples of the aliphatic diol residue include ethylene glycol, 1,3-propylene glycol, 1,4- Butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2, Residues such as 4-diethyl-1,5-pentanediol, 1,9-nonanediol, and 2-methyl-1,8-octanediol are exemplified. In particular, an aliphatic diol residue having 5 to 12 carbon atoms is preferable from the viewpoint of flexibility and low temperature characteristics of the obtained thermoplastic polyester elastomer. These components may be used independently and may use 2 or more types together as needed.
In the polyester block copolymer (A), the copolymerization amount of the soft segment component is preferably 10% by mass or more from the viewpoint of flexibility and rubber elasticity, and preferably 80% by mass or less from the viewpoint of crystallinity and moldability. It is preferably contained in the range of 15 to 80% by mass.
The soft segment component of the polyester block copolymer (A) is preferably a poly (alkylene oxide) glycol segment that is an aliphatic polyether. The content is preferably 10 to 80% by mass, more preferably 30 to 80% by mass, and still more preferably 40 to 80% by mass in the polyester block copolymer (A). The poly (alkylene oxide) glycol is preferably poly (tetramethylene oxide) glycol.

  The polyester block copolymer (A) used in the present invention can be produced by a known method. For example, a method in which a lower alcohol diester of a dicarboxylic acid, an excess amount of a low molecular weight glycol, and a soft segment component are transesterified in the presence of a catalyst and the resulting reaction product is polycondensed, a dicarboxylic acid and an excess amount of glycol and a soft A method in which the segment component is esterified in the presence of a catalyst and the resulting reaction product is polycondensed, a high-melting crystalline segment is prepared in advance, and a soft segment component is added to this to randomize by transesterification. Method, a method of linking a hard segment and a soft segment with a chain linking agent, and a method of adding an ε-caprolactone monomer to the hard segment when poly (ε-caprolactone) is used for the soft segment. .

The melt flow rate of the polyester block copolymer (A) used in the present invention needs to be 0.1 to 10 g / 10 min. The melt flow rate is measured under the conditions of a temperature of 210 ° C. and a load of 2160 g in accordance with ASTM D1238. The melt flow rate is preferably 0.1 to 9 g / 10 minutes (210 ° C., load 2160 g), more preferably 0.1 to 6 g / 10 minutes (210 ° C., load 2160 g). When the melt flow rate exceeds 10 g / 10 min, the kneadability with the ethylene vinyl alcohol copolymer (B) (EVOH resin) deteriorates and the gas barrier property decreases. When the melt flow rate is less than 0.1 g / 10 min, the polyester block copolymer The amount of the gelled product in the polymer (A) increases, which may impair the quality of the resin composition.
The method for making this melt flow rate is not particularly limited. If the polyester block copolymer (A) obtained by melt polymerization satisfies the melt flow rate, it can be used as it is. When the viscosity of the polyester block copolymer (A) obtained by melt polymerization is insufficient (when the melt flow rate exceeds 10 g / 10 minutes), a method of solid-phase polymerization after melt polymerization, an epoxy compound, an isocyanate compound, Examples thereof include a method of adding a compound capable of developing a thickening effect such as a carbodiimide compound, an oxazoline compound, and an acid anhydride and melt-kneading.

  The polyester block copolymer (A) is preferably a modified polyester block copolymer obtained by modification with an epoxy compound. An epoxy compound is preferable from the viewpoint of handleability as a compound that exhibits a thickening effect. Epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, resorcin type epoxy compounds, novolac type epoxy compounds, alicyclic compound type diepoxy compounds, glycidyl ethers, glycidyl esters, triazine skeleton-containing trifunctional epoxy compounds, Examples include epoxy group-containing acrylic polymers. These are epoxy compounds having a glycidyl group in the molecule, and the number of glycidyl groups in the molecule is preferably 2 or more on average.

Specific examples of the glycidyl ethers include diglycidyl ethers such as neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, propylene glycol diglycidyl ether, and bisphenol A diglycidyl ether.
Examples of the glycidyl esters include diglycidyl esters such as adipic acid diglycidyl ester, terephthalic acid diglycidyl ester, and orthophthalic acid diglycidyl ester.
These epoxy compounds preferably have good compatibility with the polyester block copolymer (A). For example, diethylene glycol diglycidyl ether, triazine skeleton-containing trifunctional epoxy compound, epoxy group-containing acrylic polymer, and the like are preferable.
The number average molecular weight of the epoxy compound is preferably 450 to 40000.

  As for content of an epoxy compound, 0.01-6 mass parts is preferable with respect to 100 mass parts of polyester block copolymers (A), and in order to express a thickening effect, it is contained 0.1 mass part or more. More preferred. When the content is more than 6 parts by mass, crosslinking may proceed and fluidity during molding may be deteriorated. It is particularly preferable to contain 0.2 to 3 parts by mass with respect to 100 parts by mass of the polyester block copolymer (A).

  The reduced viscosity of the polyester block copolymer (A) before thickening is preferably about 0.5 dl / g to 3.0 dl / g when measured by the measurement method described later.

[Ethylene vinyl alcohol copolymer (B)]
The ethylene vinyl alcohol copolymer (B) used in the present invention is obtained by saponifying an ethylene-vinyl ester copolymer. The ethylene content in the ethylene vinyl alcohol copolymer (B) is preferably 15 to 70 mol%, more preferably 20 to 65 mol%, still more preferably 25 to 60 mol%. The saponification degree of the vinyl ester component in the ethylene vinyl alcohol copolymer (B) is preferably 85% or more, and more preferably 90% or more. When the ethylene content is less than 15 mol%, the flexibility is poor, and the water resistance and hot water resistance tend to decrease. On the other hand, when it exceeds 70 mol%, the barrier property tends to be insufficient. On the other hand, if the degree of saponification is less than 85%, the barrier property and thermal stability may be deteriorated.

[Modified ethylene-vinyl monomer copolymer (C)]
The modified ethylene-vinyl monomer copolymer (C) used in the present invention is copolymerization, graft polymerization, post-treatment, etc., and the ethylene-vinyl copolymer has a carboxylic acid group, a carboxylic acid anhydride group, and This is an ethylene-vinyl monomer copolymer (C) modified so as to have at least one of hydroxyl groups. Examples of vinyl monomers include styrene, vinyl toluene, acrylonitrile, methacrylonitrile, vinyl acetate, methyl methacrylate, and ethyl acrylate.
The modified ethylene-vinyl monomer copolymer (C) has good compatibility with the polyester block copolymer (A) and the ethylene vinyl alcohol copolymer (B), and the stabilization of the phase structure, that is, At least one of an ethylene-vinyl monomer copolymer copolymerized with an unsaturated carboxylic acid and a partially saponified ethylene-vinyl acetate copolymer for reasons of improving the melt residence stability It is preferable that Here, the partially saponified ethylene-vinyl acetate copolymer is different from the component (B) in the saponification degree of the vinyl ester component, and the saponification degree is 20 to 60%.
Specifically, an ethylene-vinyl monomer copolymer obtained by copolymerizing an unsaturated carboxylic acid includes an ethylene-vinyl acetate-maleic anhydride terpolymer, an ethylene-ethyl acrylate-maleic anhydride ternary. Examples of the copolymer include copolymers such as an ethylene-ethyl acrylate copolymer-maleic anhydride graft copolymer and an ethylene-ethyl acrylate-maleic anhydride copolymer-acrylonitrile-styrene graft copolymer.
The modified ethylene-vinyl monomer copolymer (C) is a graft polymer having an ethylene-acrylic acid ester-maleic anhydride copolymer as a main chain and an acrylonitrile-styrene copolymer as a side chain. Is particularly preferred.

  The mass ratio of the polyester block copolymer (A) and the ethylene vinyl alcohol copolymer (B) in the present invention is (A) / (B) = 10/90 to 90/10, preferably (A ) / (B) = 10/90 to 70/30, more preferably (A) / (B) = 10/90 to 40/60. If the content of the polyester block copolymer (A) is less than 10% by mass, the resin composition may not be a flexible molded product, and the content of the polyester block copolymer (A) is 90% by mass. If it exceeds, there is a risk that sufficient barrier properties cannot be secured.

  The blending ratio of the modified ethylene-vinyl monomer copolymer (C) in the present invention to the total amount of the polyester block copolymer (A) and the ethylene vinyl alcohol copolymer (B) is [( A) + (B)] / (C) = 100 / 0.1-100 / 10, preferably [(A) + (B)] / (C) = 100 / 0.5-100 / 5, More preferably, [(A) + (B)] / (C) = 100 / 0.5 to 100/2. The modified ethylene-vinyl monomer copolymer (C) is 0.1 parts by mass with respect to 100 parts by mass of the total amount of the polyester block copolymer (A) and the ethylene vinyl alcohol copolymer (B). If the ratio is less than 10 parts by mass, the stability of the extruded strand is difficult to obtain, and the fine dispersion of the polyester block copolymer (A) tends to hardly occur.

  The flexural modulus of the thermoplastic resin composition of the present invention is preferably 2.5 GPa or less, more preferably 2.0 GPa or less, and particularly preferably 1.5 GPa or less. The lower the flexural modulus is, the more flexible the molded product or coating layer can be produced than the molded product or coating layer of EVOH resin alone, the more applicable products, and the greater the contribution to the industry.

  The polyester block copolymer (A) contained in the thermoplastic resin composition of the present invention is preferably dispersed with an average dispersed particle diameter of 2 μm or less. More preferably, it is 1 micrometer or less, Most preferably, it is 0.5 micrometer or less. When the average dispersed particle size exceeds 2 μm, the barrier property tends to decrease. The average dispersed particle size of the polyester block copolymer (A) contained in the thermoplastic resin composition is measured by the method described later.

  When the thermoplastic resin composition of the present invention is an extruded film (thickness of less than 2) having a thickness of 200 μm, the styrene monomer permeation rate of the film is 10 mg / hour or less. The styrene monomer permeation rate is preferably 5 mg / hour or less, more preferably 2.5 mg / hour or less.

The styrene monomer permeation rate (mg / hour) was determined by filling a cup device with a predetermined amount of styrene (10 g) in “moisture-proof packaging material moisture permeability test method (cup method)” of JIS Z 0208, and having a 48 mm diameter cup mouth ( A measuring film is attached and sealed in a permeation area of 18.1 cm ² ), and the cup device is placed in a predetermined temperature (60 ° C.) environment so that the measuring film side is the bottom surface and the measuring film is always in contact with styrene. From the mass of the initial cup apparatus and the mass difference of the cup apparatus after 72 hours, the transmission mass of the styrene monomer is obtained, and the styrene monomer transmission rate (mg / hour) is calculated.

  The thermoplastic resin composition of the present invention is also excellent in melt residence stability. The same extrusion comprising a thermoplastic resin composition obtained by melt residence (20 minutes at 260 ° C.) of the thermoplastic resin composition of the present invention. Even if it is a molded film, the styrene monomer permeation rate of the film is 10 mg / hour or less. Also in this case, the styrene monomer permeation rate is preferably 5 mg / hour or less, more preferably 2.5 mg / hour or less.

  The thermoplastic resin composition of the present invention includes known hindered phenol-based, phosphite-based, thioether-based, amine-based antioxidants, benzophenone-based, hindered amine-based, etc., as long as the characteristics of the present invention are not impaired. Weathering agent, fluorine-containing polymer, silicone oil, stearic acid metal salt, montanic acid metal salt, montanic acid ester wax, polyethylene wax and other anti-blocking agents, dyes and pigments and other colorants, titanium oxide, carbon black and other ultraviolet rays Blocking agent, reinforcing agent such as glass fiber, carbon fiber, potassium titanate fiber, filler such as silica, clay, calcium carbonate, calcium sulfate, glass beads, nucleating agent such as talc, silane coupling agent, flame retardant, plastic Optional additives, adhesives, adhesion aids, etc. It is possible. However, the thermoplastic resin composition of the present invention comprises the polyester block copolymer (A), the ethylene vinyl alcohol copolymer (B), and the modified ethylene-vinyl monomer copolymer (C). It is preferable to occupy 70% by mass or more in total, more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

  As a method for producing the thermoplastic resin composition of the present invention, components such as a polyester block copolymer, an ethylene vinyl alcohol copolymer, and a modified ethylene-vinyl copolymer in the present invention were mixed in a predetermined blending ratio. It may be melted and kneaded later. For mixing, a Henschel mixer, a ribbon blender, a V-type blender, or the like can be used. For melt kneading, a Banbury mixer, a kneader-type heater, a single or twin screw melt kneading extruder, or the like can be used.

  In order to describe the present invention in more detail, examples are given below, but the present invention is not limited to the examples. In addition, each measured value described in the Example is measured by the following method.

[Melting point]:
Using a differential scanning calorimeter “DSC220” manufactured by Seiko Denshi Kogyo Co., Ltd., put 5 mg of measurement sample into an aluminum pan, seal it with a lid, and hold it at 250 ° C. for 5 minutes to completely melt the sample. Then, it was quenched with liquid nitrogen, and then measured from -150 ° C. to 250 ° C. at a rate of temperature increase of 20 ° C./min. The endothermic peak of the obtained curve was taken as the melting point.

[Reduced viscosity]:
0.02 g of sufficiently dried polyester resin was dissolved in 10 ml of a mixed solvent of phenol / tetrachloroethane (mass ratio 6/4) and measured at 30 ° C. with an Ostwald viscometer.

[Melt flow rate (MFR)]:
Based on ASTM D1238, the measurement was performed under conditions of a temperature of 210 ° C. and a load of 2.16 kg.

[Extruded strand stability]
The stability of the extruded strand during melt kneading with a twin screw extruder was evaluated according to the following criteria.
(Double-circle): Strand breakage does not generate | occur | produce at all and it extrudes stably.
◯: Variation in thickness is recognized although strands are not broken.
Δ: Strand breakage sometimes occurs.
X: Strand breakage frequently occurs, and continuous take-up is difficult.

[Dispersed particle size]
It cut out so that a cross section perpendicular | vertical with respect to the flow direction of an extruded film could be observed, and the frozen section | slice was produced with the cryomicrotome. The prepared section was dyed in RuO ₄ vapor for 30 minutes, and subjected to carbon deposition to prepare a sample for observation of the dispersed particle size. A JEM transmission electron microscope manufactured by JEOL Ltd. was used at an acceleration voltage of 200 kV and observed directly at a magnification of 600 times to measure the dispersed particle size. The dispersed particle size was observed.
○: Only dispersed particles having a particle diameter of 2 μm or less are observed.
Δ: Dispersed particles having a particle diameter exceeding 2 μm are observed, but the number thereof is less than half.
X: More than half of the dispersed particles having a particle diameter exceeding 2 μm are observed.

[Flexural modulus]
Measured according to ASTM D256.

[Styrene barrier properties]
As a measurement sample, an extruded film having a thickness of 200 μm (stretch ratio of 2 or less) was prepared. Next, a cup device in “moisture-proof packaging material moisture permeability test method (cup method)” of JIS Z 0208 is filled with a predetermined amount of styrene monomer (10 g), and a 48 mm diameter cup mouth (permeation area 18.1 cm ² ) is filled. A measuring film is attached and sealed, and the cup device is placed in an environment of 60 ° C. so that the measuring film side is always on the bottom surface and the measuring film is in contact with the styrene monomer. From the mass difference of the cup apparatus after 72 hours, the transmission mass of the styrene monomer was determined, and the styrene monomer transmission rate (mg / hour) was calculated.
Moreover, after making a resin composition retain in an extruder at 260 degreeC for 20 minute (s), the extrusion film similar to the above was created, and styrene barrier property was evaluated similarly.
As reference data, the styrene barrier properties (temperature 60 ° C.) of resin components and the like used in the following examples according to this measurement method are as follows.
Polyester block copolymer A1: 3400 mg / hour Polyester block copolymer A3: 3900 mg / hour Polyamide 12 (AESN TL (manufactured by Arkema)): 10 mg / hour Ethylene vinyl alcohol copolymer B1: Less than 0.1 mg / hour

(Polyester block copolymer A1)
The polyester block copolymer A1 was polymerized according to a conventional method.
A1 is a polyether ester block copolymer having polybutylene naphthalate as a hard segment and poly (tetramethylene oxide) glycol having a number average molecular weight of 1000 as a soft segment, and the content of poly (tetramethylene oxide) glycol They were 50 mass%, melting point 189 ° C., reduced viscosity 1.8 dl / g, flexural modulus 56 MPa, melt flow rate 12 g / 10 min (210 ° C., load 2160 g).

(Polyester block copolymer A2)
0.3 parts by mass of triazine skeleton-containing trifunctional epoxy compound (TEPIC-S, manufactured by Nissan Chemical Industries, Ltd.) with respect to 100 parts by mass of the pellets of the polyester block copolymer A1, 0.4% of sodium stearate as a catalyst After mixing the mass parts, melt and knead the mixture at a temperature of 220-240 ° C in a twin screw extruder TEM-35B (manufactured by TOSHIBA MACHINERY CO., LTD.), Then discharge it into water as a strand, pelletize with a pelletizer, and polyester block Copolymer A2 was obtained. The melt flow rate was 5 g / 10 min (210 ° C., load 2160 g).

(Polyester block copolymer A3)
The polyester block copolymer A3 was polymerized according to a conventional method.
A3 is a polyetherester block copolymer having polybutylene terephthalate as a hard segment and poly (tetramethylene oxide) glycol having a number average molecular weight of 1000 as a soft segment, and having a poly (tetramethylene oxide) glycol content of 78 The mass%, the melting point was 160 ° C., the reduced viscosity was 2.7 dl / g, the flexural modulus was 15 MPa, and the melt flow rate was 14 g / 10 minutes (190 ° C., load 2160 g).

(Polyester block copolymer A4)
3 parts by mass of an epoxy group-containing acrylic polymer (UG-4050, manufactured by Toagosei Co., Ltd.) is mixed with 100 parts by mass of the pellets of the polyester block copolymer A3, and in a twin screw extruder TEM-35B. After melt-kneading the mixture at a temperature of 220 to 240 ° C., the mixture was discharged into water as a strand and pelletized with a pelletizer to obtain a polyester block copolymer A4. The melt flow rate was 2 g / 10 min (210 ° C., load 2160 g).

(Polyester block copolymer A5)
The polyester block copolymer A3 pellets are charged into a rotatable reaction vessel, the pressure in the system is reduced to 28 Pa, and heated at 130 to 150 ° C. to perform solid phase polymerization, and the polyester block copolymer A5 is obtained. Obtained. The melt flow rate was 8 g / 10 min (190 ° C., load 2160 g).

(Ethylene vinyl alcohol copolymer)
B1: EVAL (registered trademark) F104B (manufactured by Kuraray Co., Ltd .; ethylene content 32 mol%, saponification degree of vinyl ester component almost 100%)
B2: EVAL (registered trademark) G156 (manufactured by Kuraray Co., Ltd .; ethylene content 48 mol%, saponification degree of vinyl ester component almost 100%)

(Modified ethylene-vinyl copolymer)
C1: Modiper A8400 (manufactured by NOF Corporation; graft polymer having ethylene-ethyl acrylate-maleic anhydride copolymer as the main chain and acrylonitrile-styrene copolymer as the side chain)
C2: Mersen H6410M (manufactured by Tosoh Corporation; partially saponified ethylene-vinyl acetate copolymer (saponification degree 40%))
C3: Bond First 7M (manufactured by Sumitomo Chemical Co., Ltd .; ethylene-methyl acrylate-glycidyl methacrylate copolymer)

Examples 1-10, Comparative Examples 1-7
After mixing each component such as the above-mentioned polyester block copolymer, ethylene vinyl alcohol copolymer, modified ethylene-vinyl copolymer in the blending ratio shown in Table 1, the kneading zone was set at a set temperature of 235 ° C. It melt-kneaded with a twin screw extruder (TEM-35B) owned by 3 units, extruded into a strand, cooled with water, and pelletized with a pelletizer. Said evaluation was performed using this pellet. The results are shown in Table 1.

As shown in Example 1 to Example 10 in Table 1, the resin composition of the present invention has good barrier properties and good melt residence stability.
On the other hand, the resin compositions shown in Comparative Examples 1 to 3 do not have sufficient barrier properties. In addition, the resin compositions shown in Comparative Examples 4 to 7 have poor melt residence stability as compared with Examples 1 to 10.

  The resin composition of the present invention has flexibility, good barrier properties, and melt retention stability, and can produce molded products and coating layers that are more flexible than extruded products and coating layers of EVOH resin alone. In addition, the barrier property is superior to that of the polyamide 12 having the same flexibility. Therefore, it can be suitably used for many applications such as films, sheets, container materials, pipes, etc., and has significant industrial significance.

Claims (7)

Polyester block copolymer (A), ethylene vinyl alcohol copolymer (B) having a melt flow rate (ASTM D1238) of 0.1 to 10 g / 10 min (210 ° C., load 2160 g), carboxylic acid group, carvone A thermoplastic resin composition comprising a modified ethylene-vinyl monomer copolymer (C) having at least one of an acid anhydride group and a hydroxyl group in the following mass ratio.
(A) / (B) = 10/90 to 90/10
[(A) + (B)] / (C) = 100 / 0.1-100 / 10   The thermoplastic resin composition according to claim 1, wherein the polyester block copolymer (A) contains a poly (alkylene oxide) glycol segment as a soft segment component.   The thermoplastic resin composition according to claim 2, wherein the content of the poly (alkylene oxide) glycol segment in the polyester block copolymer (A) is 10 to 80% by mass.   The thermoplastic resin composition according to any one of claims 1 to 3, wherein the polyester block copolymer (A) is a modified polyester block copolymer obtained by modification with an epoxy compound.   Of the modified ethylene-vinyl monomer copolymer (C), an ethylene-vinyl monomer copolymer obtained by copolymerizing an unsaturated carboxylic acid, and a partially saponified ethylene-vinyl acetate copolymer. The thermoplastic resin composition according to any one of claims 1 to 4, which is at least one of the following.   The modified ethylene-vinyl monomer copolymer (C) is a graft polymer having an ethylene-acrylic acid ester-maleic anhydride copolymer as a main chain and an acrylonitrile-styrene copolymer as a side chain. Item 5. The thermoplastic resin composition according to any one of Items 1 to 4.   The thermoplastic resin composition according to any one of claims 1 to 6, wherein the polyester block copolymer (A) is dispersed in an average dispersed particle diameter of 2 µm or less in the thermoplastic resin composition.