JP2007270141A - Method for producing polyester resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for a film, a sheet and a thin hollow container having excellent gas-barrier properties, transparency, hue and mechanical properties, comprising an aromatic polyester resin and a polyamide resin; and to provide a molded article and the like obtained by molding the composition. <P>SOLUTION: The polyester resin composition is obtained by melt-kneading a polyamide resin composed of a constituent unit mainly derived from meta-xylylenediamine and adipic acid, and a polyester resin composed of a constituent unit mainly derived from an aromatic dicarboxylic acid and an aliphatic diol, and a polycarboxylic acid compound selected from specific aromatic or alicyclic compounds, at a specified ratio by a specific procedure. The method for producing the composition is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a polyester resin composition obtained by melt-kneading a polyamide resin, a polyester resin, and a polyvalent carboxylic acid compound having specific properties in a specific ratio and procedure, and a method for producing the same.

A polyester resin (hereinafter, sometimes referred to as “aromatic polyester resin”) having an aromatic dicarboxylic acid as a main dicarboxylic acid component and an aliphatic diol as a main diol component, represented by polyethylene terephthalate (PET), is mechanical. It has features such as excellent performance, melt stability, solvent resistance, aroma retention, and recyclability. Therefore, aromatic polyester resins are widely used for packaging materials such as films, sheets, and hollow containers. However, since gas barrier properties such as oxygen and carbon dioxide gas are not always good, there is a limit to use in applications that require high gas barrier properties. As means for imparting gas barrier properties to the aromatic polyester resin, there are means such as laminating a metal foil such as aluminum, applying or laminating other resin having high gas barrier properties, vapor deposition of aluminum or silicon, etc. However, there are problems that transparency is impaired, a complicated manufacturing process is required, and mechanical performance is impaired.

As a means for imparting a high gas barrier property without requiring a complicated manufacturing process, there is a method of mixing another resin having a high gas barrier property. Polyamide resins typified by nylon 6, nylon 66, etc. are examples of resins having high gas barrier properties. Particularly, polyamide resins obtained by polymerizing metaxylylenediamine and adipic acid (hereinafter referred to as “polyamide MXD6”). Is excellent in gas barrier properties. On the other hand, there is an ethylene-polyvinyl alcohol copolymer resin as a gas barrier resin other than the polyamide resin, but since the ethylene-polyvinyl alcohol copolymer resin is poorly compatible with the aromatic polyester resin, both compositions are cloudy, Since the crystallinity is high, there are problems such as impairing the stretchability of the aromatic polyester resin and inferior thermal stability.

On the other hand, polyamide MXD6 has a high gas barrier property, and is close to the glass transition temperature, melting point and crystallinity of aromatic polyester resin, particularly polyethylene terephthalate, and is excellent in thermal stability during melting. Therefore, there exists an advantage that high gas-barrier property expresses, without impairing the mechanical performance and stretchability of an aromatic polyester resin, which can be easily melt-mixed with the aromatic polyester resin.

However, a composition of an aromatic polyester resin and a polyamide resin such as polyamide MXD6 causes pearly glare depending on the dispersion state and concentration of the constituent composition, and particularly, glare becomes noticeable due to thermoforming such as stretching, and transparency is high. There is a tendency to decrease. Thus, since the composition of an aromatic polyester resin and a polyamide resin such as polyamide MXD6 is not sufficiently transparent, its use is limited in applications where high transparency is required.

Patent Document 1 proposes a composition obtained by adding tetracarboxylic dianhydride to a mixture composed of a polyamide resin and a polyester resin. However, although the said patent document 1 has description regarding the improvement of the mechanical property of the molded article used as engineering plastics, the description regarding the resin composition for films, sheets, and thin-walled hollow containers with improved transparency Is not at all. Patent Document 2 proposes a compound having an epoxy group and an acid anhydride group as one type of compatibilizing agent for a composition of a thermoplastic polyester resin and a polyamide resin having a metaxylylene group in the main chain. However, this compound is clearly different from the compound of the present invention.

Patent Document 3 proposes a composition obtained by adding tetracarboxylic dianhydride to a mixture composed of a polyamide resin and a polyester resin. However, since tetracarboxylic dianhydride has reactivity with the polyester resin and polyamide resin to be mixed, it causes an excessive increase in viscosity of the resin composition at the time of mixing and molding processing, resulting in film, sheet and thin hollow container. There is a problem that the molding process may be difficult, and the addition causes a yellow to brown coloration, which impairs the appearance of the molded product.

In Patent Literature 4, a polyvalent carboxylic acid compound having three or more carboxyl groups in one molecule and a polyvalent carboxylic acid compound having an acid anhydride group are added to a mixture composed of a polyamide resin and a polyester resin. Compositions have been proposed. However, since the polycarboxylic acid anhydride has reactivity with the polyester resin and the polyamide resin to be mixed as in the above reason, it causes an excessive increase in the viscosity of the resin composition during the mixing and molding process, and the film, sheet In addition, there is a possibility that the molding process into a thin-walled hollow container may be difficult, and the addition causes a yellow to brown coloration, thereby impairing the appearance of the molded product. As described above, development of a polyester resin composition having high gas barrier performance and excellent transparency without requiring a complicated production process is desired.
JP-A-1-272660 Japanese Patent Laid-Open No. 62-201963 JP 2000-34357 A JP 2000-302952 A

An object of the present invention is to provide a method for producing a resin composition containing an aromatic polyester resin and a polyamide resin, which is excellent in gas barrier properties, transparency and mechanical performance, and is difficult to be colored.

As a result of intensive studies, the present inventors have found that the above problems can be solved by melt-kneading a polyamide resin having a specific property, a polyvalent carboxylic acid compound, and a polyester resin in a specific ratio and procedure. The present invention has been completed.

That is, in the present invention, a polyamide resin (A) of 10 to 40% by weight, dicarboxylic acid having 70 mol% or more of diamine structural units derived from metaxylylenediamine and 70 mol% or more of dicarboxylic acid structural units derived from adipic acid. 70 to 89.95% by weight of polyester resin (B) in which 70 mol% or more of the acid structural unit is derived from an aromatic dicarboxylic acid and 70 mol% or more of the diol structural unit is derived from an aliphatic diol, and aromatic 3 At least one polycarboxylic acid compound selected from the group consisting of monovalent carboxylic acids, alicyclic trivalent carboxylic acids, aromatic divalent carboxylic acids, alicyclic divalent carboxylic acids, and acid anhydrides of said carboxylic acids (C) After obtaining a master batch (D) in which 0.05 to 1% by weight (the total of the weight% is 100% by weight) is previously melt-kneaded, the master Melting and kneading a batch (D) and a polyester resin (E) in which 70 mol% or more of dicarboxylic acid structural units are derived from aromatic dicarboxylic acid and 70 mol% or more of diol structural units are derived from aliphatic diol Thus, the polyamide resin (A) is 2 to 30% by weight, the polyester resins (B) and (E) are 69.5 to 99.99% by weight, and the polyvalent carboxylic acid compound (C) is 0.01 to 0.00. A method for producing a polyester resin composition comprising 5% by weight (total of 100% by weight is 100% by weight),
The following formulas (1) to (2):
100 ≦ a ≦ 250 (1)
0.1 ≦ a / b ≦ 0.5 (2)
(In the above formula, a and b are as follows.
a is the melt viscosity (Pa · sec) of the master batch (D) measured under the conditions of 280 ° C. and a shear rate of 100 / sec; b is the melt viscosity (Pa · sec) of the polyester resin (E) measured under the above conditions. is there)
It is related with the manufacturing method of the polyester resin composition characterized by satisfying.

The present invention also relates to a resin composition obtained by the production method, and molded articles such as films, sheets and hollow containers obtained by molding the resin composition.
The polyester resin composition of the present invention can be used for films, sheets, and hollow containers, and is obtained by a T-die method, a coextrusion method or the like, a non-stretched or low-magnification single-layer sheet and a multilayer sheet, and a film obtained by stretching them. And deep drawing containers with low draw ratio, and high transparency such as thin hollow containers with a wall thickness of 0.1 to 2 mm obtained by direct blow molding and stretch blow molding, which are unstretched after molding It can be used as a material for packaging molded bodies that require high performance.

The polyester resin composition of the present invention is a non-stretched or low-magnification single-layer sheet or multilayer sheet obtained by a T-die method, a co-extrusion method, etc., a film obtained by stretching them, a deep-drawing container with a low stretch ratio, Is excellent in moldability while maintaining the gas barrier properties of the obtained film, sheet and thin-walled hollow container. Transparency, hue, and mechanical performance can be imparted.

In the present invention, at least one kind of polyamide resin (A), at least one kind of polyester resin (B), at least one kind of polyester resin (E), and at least one kind of polycarboxylic acid compound (C) are contained in a predetermined ratio. It is the method of manufacturing the polyester resin composition contained in. Hereinafter, each component will be described in detail.

The polyamide resin (A) is obtained by polycondensation of diamine and dicarboxylic acid. In the polyamide resin (A), 70 mol% or more of the diamine structural unit (structural unit derived from diamine) is derived from metaxylylenediamine, and 70 mol% of the dicarboxylic acid structural unit (structural unit derived from dicarboxylic acid). The above is the polyamide resin derived from adipic acid. The structural unit derived from metaxylylenediamine needs to be 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more. If the structural unit derived from metaxylylenediamine is less than 70 mol%, the excellent gas barrier property of the polyamide resin becomes insufficient. Moreover, the structural unit derived from adipic acid needs to be 70 mol% or more, Preferably it is 80 mol% or more, More preferably, it is 90 mol% or more. When the structural unit derived from adipic acid is less than 70 mol%, the gas barrier property is lowered and the crystallinity is excessively lowered. Particularly preferred as the polyamide resin (A) is polymetaxylylene adipamide. The polyamide resin having the monomer composition and the structural unit as described above is advantageous because it does not impair the processability of the polyester resin composition because the moldability is similar to that of a polyester resin such as a polyethylene terephthalate resin.

As diamines that can be used in addition to metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, Examples include 2-methyl-1,5-pentanediamine, but are not limited thereto.
Examples of dicarboxylic acids that can be used in addition to adipic acid include suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, but are not limited thereto. It is not something.
In addition, a small amount of monoamine or monocarboxylic acid may be added as a molecular weight regulator during the polycondensation for producing the polyamide resin (A).

The polyamide resin (A) is preferably produced by a polycondensation reaction in a molten state (hereinafter sometimes referred to as “melt polycondensation”). For example, it is preferable to produce a nylon salt composed of metaxylylenediamine and adipic acid by heating in the presence of water by a pressure method and polymerizing in a molten state while removing added water and condensed water. Alternatively, it may be produced by a method in which metaxylylenediamine is directly added to molten adipic acid and polycondensed under normal pressure. In this case, in order to keep the reaction system in a uniform liquid state, metaxylylenediamine is continuously added to adipic acid, and during that time, the reaction system is set so that the reaction temperature does not fall below the melting point of the generated oligoamide and polyamide. It is preferable to advance polycondensation while raising the temperature. The polyamide obtained by melt polycondensation may be further solid-phase polymerized to increase the molecular weight. The solid phase polymerized polyamide thus obtained may be used as the polyamide resin (A).

The concentration of the polyamide resin (A) in the polyester resin composition is 2 to 2 with respect to the total weight of the polyamide resin (A) and the polyester resin (B), the polyvalent carboxylic acid compound (C) and the polyester resin (E). It is 30% by weight, preferably 2 to 20% by weight, more preferably 2 to 15% by weight, still more preferably 2 to 10% by weight, and particularly preferably 2 to 5% by weight. If it is less than 2% by weight, good gas barrier performance cannot be obtained. If it exceeds 30% by weight, the gas barrier performance is good, but the transparency of the resulting packaging molded article is lowered, and the mechanical performance is also lowered, resulting in a low commercial value.

The relative viscosity of polyamide resin (A) (value obtained by dissolving 1 g of polyamide resin in 100 ml of 96% sulfuric acid and measuring at 25 ° C.) is preferably 1.83 to 4.20, more preferably 2.02 to 4.20. More preferably, it is 2.30-4.20. When the relative viscosity is within the above range, when molding a film, sheet, hollow container or the like comprising the polyester resin composition of the present invention, the fluidity of the molten resin is good and die swell and melting unevenness are reduced, and the moldability is good. become. Further, the transparency of the molded product is improved, and a decrease in transparency due to whitening under a high humidity atmosphere can be suppressed.

The polyamide resin (A) having a relative viscosity of 2.30 or more can be easily obtained by continuing the reaction until a predetermined relative viscosity is reached during melt polymerization. However, if the reaction is continued to a predetermined relative viscosity by melt polymerization, the time for maintaining the molten state (reaction time) becomes longer, the polyamide molecules are damaged, or abnormal reactions such as non-linear molecular growth (3 Dimensional polymerization) occurs, and gels and fish eyes are generated. A molded product made of a polyester resin composition using a polyamide resin having a large amount of gel or fish eyes may generate fish eyes and reduce productivity.

  Polyamide resin (A) having a relative viscosity of 2.30 or more is produced by producing a melt-polymerized polyamide resin so that the relative viscosity is 2.28 or less. Then, it is preferably produced by a method of making the relative viscosity 2.30 or more by solid-phase polymerization of the melt-polymerized polyamide resin. In solid-phase polymerization, pellets or powder of a melt-polymerized polyamide resin having a relative viscosity of 1.83 to 2.28 is heated to a temperature in the range of 120 ° C. or higher and lower than the melting point of the polyamide resin under reduced pressure or in an inert gas atmosphere. It is carried out by doing. The relative viscosity of the solid phase polymerized polyamide resin obtained by solid phase polymerization is preferably 2.30 to 4.20.

The polyester resin composition using the polyamide resin (A) whose relative viscosity is increased to 2.30 or more by solid phase polymerization has very good moldability to a molded body such as a film, a sheet, and a hollow container. Moreover, since there are few fish eyes in a solid-phase-polymerized polyamide resin, it is reduced that the fish eye resulting from a polyamide resin generate | occur | produces in a molded object, and productivity improves remarkably.

The polyamide resin (A) preferably has a melt viscosity of 100 to 2000 Pa · sec under the conditions of 280 ° C. and a shear rate of 100 / sec. By using the polyamide (A) having an appropriate viscosity in the above range, the dispersibility in the polyester resin is improved, and a polyester resin composition having excellent transparency and mechanical performance of the molded product is obtained.

The moisture content of the polyamide resin (A) is preferably 0.15% by weight or less, more preferably 0.1% by weight or less. When the moisture content is 0.15% by weight or less, hydrolysis of the polyester resin (B) caused by moisture generated from the polyamide resin (A) during melt mixing with the polyester resin (B) can be suppressed. In this case, the polyamide resin may be dried and used as the moisture content. The polyamide resin can be dried by a conventionally known method. For example, when a polyamide resin is melt-extruded with a vented extruder, the moisture in the polymer is removed by depressurizing the vent hole, and the polyamide resin is charged in a tumbler (rotary vacuum tank) Although the method etc. which heat and dry at the temperature below the melting point of a polyamide resin are mentioned, it is not limited to this.

The polyamide resin (A) may contain a phosphorus compound in order to improve processing stability during melt molding or to prevent the polyamide resin from being colored. As the phosphorus compound, a phosphorus compound containing an alkali metal or an alkaline earth metal is preferably used. Examples thereof include phosphates such as sodium, magnesium and calcium, hypophosphites and phosphites, and alkali metals. Alternatively, a material using an alkaline earth metal hypophosphite is preferably used because it is particularly excellent in the anti-coloring effect of the polyamide. The concentration of the phosphorus compound in the polyamide resin (A) is preferably 200 ppm or less, more preferably 160 ppm or less, and still more preferably 100 ppm or less as a phosphorus atom. When the phosphorus atom concentration in the polyamide resin (A) is 200 ppm or less, the antimony catalyst slightly remaining in the polyester resin can be reduced when melt mixed with the polyester resin produced using the antimony catalyst. The darkening caused is prevented. In addition to the above phosphorus compounds, the polyamide resin (A) includes lubricants, matting agents, heat stabilizers, weather stabilizers, ultraviolet absorbers, nucleating agents, plasticizers, flame retardants as long as the effects of the present invention are not impaired. In addition, an antistatic agent, an anti-coloring agent, an anti-gelling agent, and other additives can be added.

The polyester resins (B) and (E) are obtained by polymerizing a dicarboxylic acid and a diol, and 70 mol% or more of the dicarboxylic acid structural unit (the structural unit derived from the dicarboxylic acid) is derived from the aromatic dicarboxylic acid, And 70 mol% or more of a diol structural unit (structural unit derived from diol) originates in aliphatic diol. The proportion of the structural unit derived from the aromatic dicarboxylic acid is 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more. The proportion of the structural unit derived from the aliphatic diol is 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more. In addition, (B) and (E) may have the same composition and properties, or may have different compositions and properties.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, naphthalenedicarboxylic acid such as 2,7-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. 3,4′-biphenyldicarboxylic acid and the like, and ester-forming derivatives thereof. As the polyester resin (B) or (E), an aliphatic dicarboxylic acid such as adipic acid, azelaic acid or sebacic acid, or a monocarboxylic acid such as benzoic acid, propionic acid or butyric acid may be used as long as the object of the present invention is not impaired. Can do.
Examples of the aliphatic diol include ethylene glycol, 1,3-propylene diol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, and the like, and ester-forming derivatives thereof. Polyester resins (B) or (E) may contain monoalcohols such as butyl alcohol, hexyl alcohol and octyl alcohol, and polyhydric alcohols such as trimethylolpropane, glycerin and pentaerythritol, as long as the object of the present invention is not impaired. It can also be used.

For the production of the polyester resin (B) or (E), a direct esterification method or a transesterification method, which are known methods, can be applied. Polycondensation catalysts used in the production of the polyester resin (B) or (E) include known antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds such as germanium oxide, titanium compounds such as titanium acetate, and aluminum chloride. Examples thereof include, but are not limited to, aluminum compounds.

Preferred polyester resins (B) or (E) include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polyethylene-2,6-naphthalene dicarboxylate. Chelate resin, polyethylene-2,6-naphthalene dicarboxylate-terephthalate copolymer resin, polyethylene-terephthalate-4,4′-biphenyldicarboxylate resin, poly-1,3-propylene-terephthalate resin, polybutylene terephthalate resin, Examples include polybutylene-2,6-naphthalenedicarboxylate resin. More preferable polyester resins (B) or (E) include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polybutylene terephthalate resin, and polyethylene-2. , 6-naphthalenedicarboxylate resin.

The polyester resins (B) and (E) preferably have a moisture content of 200 ppm or less, more preferably 100 ppm or less. In this case, the polyester resin may be dried and used as the moisture content. When the moisture content is within the above range, the polyester does not hydrolyze in the melt mixing step and the molecular weight does not extremely decrease.

The intrinsic viscosity (value measured at 25 ° C. in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 60/40 weight ratio) of the polyester resins (B) and (E) is 0.5-2. 0 dl / g is preferable, More preferably, it is 0.7-1.5 dl / g. When the intrinsic viscosity is within the above range, the polyester resin has a sufficiently high molecular weight, and a molded product having mechanical properties necessary for each application can be obtained.

In the present invention, the total concentration of the polyester resins (B) and (E) in the polyester resin composition is the polyamide resin (A) and the polyester resin (B), the polyvalent carboxylic acid compound (C), and the polyester resin (E). 69.5 to 99.99% by weight, preferably 79.6 to 99.99% by weight, more preferably 84.7 to 99.99% by weight, and 90 to 99.99% by weight. % Is more preferable, and 95 to 99.99% by weight is particularly preferable. By setting it as the above range, excellent gas barrier performance, transparency, and mechanical performance can be imparted.

The polycarboxylic acid compound (C) is an aromatic or alicyclic compound having 2 to 3 carboxyl groups in one molecule, or two of the carboxyl groups form an acid anhydride group. (Having 0 to 1 carboxyl group and 1 acid anhydride group). That is, the polyvalent carboxylic acid compound (C) is at least selected from an aromatic trivalent carboxylic acid, an alicyclic trivalent carboxylic acid, an aromatic divalent carboxylic acid, an alicyclic divalent carboxylic acid, and the acid anhydride. It consists of one kind of polyvalent carboxylic acid compound. The acid anhydride is an intramolecular acid anhydride.

Examples of the polyvalent carboxylic acid compound (C) include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid (including positional isomers) and anhydrides thereof, and anthracene dicarboxylic acid (including positional isomers). ) And its anhydride, biphenyldicarboxylic acid (including positional isomer) and its anhydride, benzophenone dicarboxylic acid (including positional isomer) and its anhydride, cyclohexanedicarboxylic acid (including positional isomer) and its anhydride , Trimellitic acid, trimellitic anhydride, hemimellitic acid and its anhydride, trimesic acid, 1,2,4-cyclohexanetricarboxylic acid and its anhydride, 1,2,3-cyclohexanetricarboxylic acid and its anhydride, 1 , 3,5-cyclohexanetricarboxylic acid, naphthalenetricarbo Acids (including positional isomers) and anhydrides, anthracentricarboxylic acids (including positional isomers) and anhydrides, biphenyltricarboxylic acids (including positional isomers) and anhydrides, benzophenone tricarboxylic acids (positional isomers) And the anhydrides thereof.
Of these, phthalic acid, phthalic anhydride, trimellitic acid and trimellitic anhydride are preferred, phthalic anhydride, trimellitic acid and trimellitic anhydride are more preferred, phthalic anhydride and trimellitic anhydride are more preferred, and trimellitic anhydride is preferred. Mellitic acid is particularly preferred.

The concentration of the polyvalent carboxylic acid compound (C) in the polyester resin composition is based on the total weight of the polyamide resin (A), the polyester resin (B), the polyvalent carboxylic acid compound (C), and the polyester resin (E). 0.01 to 0.5% by weight, preferably 0.01 to 0.4% by weight, and more preferably 0.01 to 0.3% by weight. By setting it as the above range, excellent gas barrier performance, transparency, and mechanical performance can be obtained.

The (melt viscosity of the polyamide resin (A)) / (melt viscosity of the polyester resin (B)) is preferably 0.3 to 1.2. The melt viscosity is measured at an apparent shear rate of 100 / sec at 270 ° C. When it is in the above range, a molded article having further excellent transparency can be obtained.

The process for producing the polyester resin composition of the present invention is as follows. After the polyamide resin (A), the polyester resin (B) and the polyvalent carboxylic acid compound (C) are melt-kneaded to obtain a master batch (D), the polyester resin is further produced. A polyester resin composition is obtained by melt-kneading with (E). The composition of the masterbatch (D) in the present invention is 10 to 40% by weight of the polyamide resin (A), 89.95 to 59.00% by weight of the polyester resin (B), 0.05 to 1% by weight of the polyvalent carboxylic acid compound. It is.
Moreover, the following relational expressions (1) to (2) are satisfied.
100 ≦ a ≦ 250 (1)
0.1 ≦ a / b ≦ 0.5 (2)
Here, a and b are as follows.
a: Melt viscosity (Pa · sec) of the master batch (D)
b: Melt viscosity (Pa · sec) of polyester resin (E)
Measurement conditions for a and b: 280 ° C., shear rate 100 / sec
Since the master batch (D) has an appropriate viscosity by satisfying the formula (1), the polyamide resin (A) can be further finely dispersed when melt-kneaded with the polyester resin (E), and the resulting molding is obtained. Body transparency and mechanical performance are improved. In order to obtain a masterbatch (D) satisfying the formula (1), selection of the polyamide resin (A) and polyester resin (B) to be used, drying conditions, kneading conditions, and composition ratio with the polyvalent carboxylic acid compound (C) It is necessary to adjust. In addition, by using the polyester resin (E) that satisfies the formula (2), not only can fine dispersion be more suitable at the time of melt kneading, but also deterioration and coloring of the resin can be reduced by excessive heat generation during kneading. It becomes possible.

The polyester resin composition of the present invention can be produced by a conventionally known method and apparatus. For example, a polyamide resin (A), a polyester resin (B), and a polyvalent carboxylic acid compound (C) are dry blended with a tumbler, V-type blender, Henschel mixer, etc. Using master batch (D) melt-mixed at least once with a screw extruder, kneader, etc., and further solid-phase polymerizing master batch (D) under high vacuum or inert gas atmosphere as necessary Among these, among these, the melt kneading method using a twin screw extruder is a preferred method in the present invention.

  In the present invention, when the master batch (D) is produced by melt-kneading the polyamide resin (A), the polyester resin (B) and the polyvalent carboxylic acid compound (C) using a twin screw extruder, The melt kneading temperature is preferably 200 to 300 ° C, more preferably 220 to 290 ° C. In addition, when a combination of parts such as a reverse screw element and a kneading disk is used in the screw mixing section in the extruder, the screw can be efficiently dispersed.

Since a molded article having good transparency can be obtained, it is preferable that the polyamide resin (A) is finely dispersed in the polyester resin composition of the present invention. For example, in a molded body before secondary processing such as stretch thermoforming such as a parison, an unstretched sheet, and a nonstretched film, the average dispersed particle size of the polyamide resin (A) is preferably 0.35 μm or less, and 0.05 to 0 .35 μm is more preferable.

The polyester resin composition of the present invention includes other resins, pigments, dyes, carbon black, lubricants, matting agents, heat stabilizers, weather stabilizers, UV absorbers, as long as the effects of the present invention are not impaired. In addition, fluorescent whitening agents, nucleating agents, plasticizers, flame retardants, antistatic agents, alkali compounds that prevent gelation of polyamide resins, and the like may be included. The amount of the other resin is preferably 20% by weight or less with respect to the total amount of the polyester resin composition, and the total amount of additives is preferably 5% by weight or less. Examples of other resins include polyester resins such as polyethylene naphthalate resin and polybutylene terephthalate resin; polyamide resins such as nylon 6, nylon-6IT and nylon 66; and polyolefins such as polyethylene and polypropylene.

Further, the polyester resin composition of the present invention includes a polyethylene terephthalate product recovered product, a modified polyethylene terephthalate product recovered containing a small amount of isophthalic acid component units, a polyamide product recovered product, and a material that does not substantially change its properties. It is also possible to add scraps at the time of manufacturing the molded article and polyester and / or polyamide resin recovered material such as non-standard products.

  The polyester resin composition of the present invention can be used as a material for a molded body that requires high transparency. Examples of the molded body include a non-stretched or low-stretch ratio single-layer sheet and multilayer sheet obtained by a T-die method, a co-extrusion method, etc., a film obtained by stretching the sheet, and a low-stretch ratio depth obtained from the sheet. Examples thereof include a non-stretched or stretched thin-walled hollow container having a barrel wall thickness of 0.1 to 2 mm obtained by a drawn container, direct blow molding and stretch blow molding. These molded articles can be used as packaging materials for foods, beverages, medicines, electronic parts and the like.

The molded article of the present invention has excellent gas barrier performance, transparency, and mechanical performance.
For example, in a 500 mL bottle, the oxygen permeability at 23 ° C. and 60% RH is 0.035 cc / bottle · day · 0.21 atm or less, the haze is 8% (thickness 300 μm) or less, and the yellowness (YI) is 12 It becomes as follows.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to a following example. In addition, the evaluation method employ | adopted by the present Example and the comparative example is as follows.

(1) 1 g of relative viscosity polyamide resin was precisely weighed and dissolved in 100 ml of 96% sulfuric acid with stirring at 20-30 ° C. After completely dissolving, 5 cc of the solution was quickly taken into a Cannon Fenceke viscometer, and allowed to stand in a constant temperature bath at 25 ° C. for 10 minutes, and then the dropping speed (t) was measured. Further, the dropping speed (t0) of 96% sulfuric acid itself was measured in the same manner. The relative viscosity was calculated from t and t0 by the following formula (A).
Relative viscosity = t / t0 (A)

(2) Intrinsic viscosity of polyester resin 0.5 g of polyester resin is precisely weighed and dissolved in 100 ml of a phenol / 1,1,2,2-tetrachloroethane (= 6/4 weight ratio) mixed solvent at 120 ° C. with stirring and dissolved. A solution of 0.5 g / dl was obtained. After cooling, the stock solution was diluted with the same solvent to obtain a 1/2 diluted solution (concentration 0.25 g / dl) and a 1/5 diluted solution (concentration 0.1 g / dl). Thereafter, the dropping time of each solution at 25 ° C .: tc and the dropping time to of the solvent were measured with an automatic viscosity measuring device (SS-600-L1 manufactured by Shibayama Scientific Instruments), and the specific viscosity ηsp and concentration C Ratio: The intrinsic viscosity was determined by searching the concentration of ηsp / C to zero.
Specific viscosity ηsp = (tc / to) −1
Intrinsic viscosity [η] = lim _{C → 0} (ηsp / C)

(3) Moisture content (wt%)
The moisture content is measured using a Karl Fischer trace moisture analyzer (CA-05 type) and a vaporizer (VA-05 type) manufactured by Mitsubishi Chemical Corporation. The moisture content was determined.

(4) Yellowness: YI
According to JIS K-7105. As the measuring device, a cloudiness value measuring device (model: COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd. was used.

(5) Haze value: Haze
According to JIS K-7105. As the measuring device, a cloudiness value measuring device (model: COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd. was used.

(6) Oxygen permeability According to ASTM D3985. A measuring device manufactured by Modern Controls (model: OX-TRAN 2/21) was used. The measurement conditions are a temperature of 23 ° C., a relative humidity of 50% outside the bottle, and 100% inside the bottle.

(7) As a melt viscosity measuring apparatus, Capillograph D-1 manufactured by Toyo Seiki Co., Ltd. was used, and measurement was performed under conditions of a die: 1 mmφ × 10 mm length, a shear rate of 100 / sec, and a measurement temperature of 280 ° C.

(8) Dispersion particle size measurement (transmission electron microscope observation)
Using an ultramicrotome (CR-X Power Tome XL manufactured by Boeckler Instruments), an ultrathin film for observation having a thickness of about 0.1 μm was cut out from the bottle (parison) body vertically to the MD (vertical) direction. The polyamide was dyed with ruthenium chloride vapor and then observed with an electron microscope on a copper mesh.
Observation conditions Electron microscope: manufactured by Hitachi, surface observation type electron microscope S4800
Acceleration voltage: 30 kV
Current: 10mA
Measurement magnification: 25,000 times Measurement mode: TEM
The dispersion state was observed based on the density of the dyed polyamide, and the average dispersed particle size was determined.

<Example 1>
The following polyester resin (B), polyamide resin (A) and polyvalent carboxylic acid compound (C) are mixed with a tumbler, and an extrusion temperature of 280 using a twin screw extruder (screw diameter: 20 mmφ, L / D: 25). The mixture was melt-kneaded while reducing the pressure inside the extruder cylinder with a vacuum pump under the conditions of ℃ and extrusion rate of 15 kg / h, and the extruded strand was pelletized to obtain pellets.

Polyester resin (B): Polyethylene terephthalate resin (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT553C, intrinsic viscosity 0.84 dl / g, melt viscosity 500 Pa · sec, moisture 110 ppm) 79.8 parts by weight Polyamide Resin (A): Polyamide MXD6 (Mitsubishi Gas Chemical Co., Ltd. MX nylon, grade: S6007, relative viscosity 2.65, melt viscosity 500 Pa · sec, moisture 300 ppm) 20 parts by weight Polycarboxylic acid compound (C): anhydrous Trimellitic acid (Mitsubishi Gas Chemical Co., Ltd., hereinafter abbreviated as TMAn) 0.2 parts by weight

The obtained pellets were vacuum-dried at 150 ° C. for 6 hours to obtain a master batch (D) pellet of a polyethylene terephthalate resin composition. The masterbatch (D) has a melt viscosity of 130 Pa · sec and a water content of 130 ppm. The masterbatch (D) pellets are 25% by weight and the polyester resin (E) is a polyethylene terephthalate resin (manufactured by Nippon Unipet Co., Ltd., trade name). : UNIPET, grade: RT553C, intrinsic viscosity 0.84 dl / g, melt viscosity 500 Pa · sec, moisture 90 ppm) was dry blended with a tumbler, and the mixture was injection-molded (M200PDM, manufactured by Meiki Seisakusho Co., Ltd.). MJ) to obtain a parison having a length of 96 mm, a wall thickness of 4.0 mm, an outer diameter of 22.5 mm, and a weight of 27 g. Injection molding was performed under the conditions of a resin temperature of 280 ° C., a mold temperature of 15 ° C., and a screw rotation speed of 150 rpm.
The body part of the obtained parison was observed with an electron microscope, and the dispersed particle diameter of the polyamide resin (A) in a cross-sectional area of about 19 square μm was measured. As a result, the average dispersed particle size was 0.18 μm.
The obtained parison was biaxially stretched and blow molded by a blow molding apparatus (EFB1000ET manufactured by Frontier Co., Ltd.) to obtain a biaxially stretched blow bottle having a height of 223 mm, a body diameter of 65 mm, a capacity of 500 mL, and an average thickness of about 300 μm. It was. The obtained bottle has a barrel Haze of 5.5% / 300 μm, YI 8.7, oxygen permeability of 0.020 cc / bottle · day · 0.21 atm, little coloration, good transparency, gas barrier performance Met. The results are shown in Table 1.

<Example 2>
Except for using polyethylene terephthalate resin (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT580CA (inherent viscosity 1.17 dl / g, melt viscosity 650 Pa · sec, moisture 150 ppm)) as the polyester resin (E). Under the same conditions as in Example 1, a parison and a stretch blow bottle were obtained. The average dispersion particle diameter of the polyamide resin (A) in the parison body is 0.15 μm, the obtained bottle has a haze of 5.2% / 300 μm, YI 8.4, and an oxygen transmission rate of 0.019 cc. /Bottle·day·0.21 atm. The obtained bottle was less colored and had good transparency and gas barrier performance. The results are shown in Table 1.

<Example 3>
The same as Example 1 except that polyamide MXD6 (Mitsubishi Gas Chemical Co., Ltd. MX nylon, grade: 6000, relative viscosity 2.10, melt viscosity 200 Pa · sec, moisture 400 ppm) was used as the polyamide resin (A). Under the conditions, a parison and a stretch blow bottle were obtained. The average dispersion particle diameter of the polyamide resin (A) at the parison body is 0.19 μm, the obtained bottle is Haze 6.6% / 300 μm, YI 9.3, and the oxygen permeability is 0.020 cc. /Bottle·day·0.21 atm. The obtained bottle was less colored and had good transparency and gas barrier performance. The results are shown in Table 1.

<Example 4>
Polyester terephthalate resin (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT580CA (inherent viscosity 1.17 dl / g, melt viscosity 650 Pa · sec, moisture 150 ppm)) as polyester resins (B) and (E) A parison and a stretch blow bottle were obtained under the same conditions as in Example 1 except that they were used. The average dispersion particle diameter of the polyamide resin (A) in the parison body is 0.13 μm, the obtained bottle is Haze 4.8% / 300 μm, YI 8.6 in the body, and the oxygen permeability is 0.019 cc. /Bottle·day·0.21 atm. The obtained bottle was less colored and had good transparency and gas barrier performance. The results are shown in Table 1.

<Example 5>
Except for using a polyethylene terephthalate resin (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT580CA (inherent viscosity 1.17 dl / g, melt viscosity 650 Pa · sec, moisture 150 ppm)) as the polyester resin (B). Under the same conditions as in Example 1, a parison and a stretch blow bottle were obtained. The average dispersion particle size of the polyamide resin (A) in the parison body is 0.19 μm, the obtained bottle is Haze 5.3% / 300 μm, YI 9.5 in the body, and the oxygen permeability is 0.020 cc. /Bottle·day·0.21 atm. The obtained bottle was less colored and had good transparency and gas barrier performance. The results are shown in Table 1.

<Example 6>
The same as Example 1 except that polyamide MXD6 (Mitsubishi Gas Chemical Co., Ltd. MX nylon, grade: S6121, relative viscosity 3.48, melt viscosity 1400 Pa · sec, moisture 200 ppm) was used as the polyamide resin (A). Under the conditions, a parison and a stretch blow bottle were obtained. The average dispersion particle diameter of the polyamide resin (A) in the parison body is 0.26 μm, the obtained bottle is Haze 7.8% / 300 μm, YI 9.8 in the body, and the oxygen permeability is 0.021 cc. /Bottle·day·0.21 atm. The obtained bottle was less colored and had good transparency and gas barrier performance. The results are shown in Table 1.

<Example 7>
Except for using polyethylene terephthalate resin (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT523C (inherent viscosity 0.72 dl / g, melt viscosity 200 Pa · sec, moisture 150 ppm)) as the polyester resin (B). Under the same conditions as in Example 1, a parison and a stretch blow bottle were obtained. The average dispersion particle size of the polyamide resin (A) in the parison body is 0.28 μm, the obtained bottle has a haze of 6.8% / 300 μm, YI 9.7, and an oxygen permeability of 0.021 cc. /Bottle·day·0.21 atm. The obtained bottle was less colored and had good transparency and gas barrier performance. The results are shown in Table 1.

<Example 8>
The composition ratio of the master batch (D) was set to polyamide resin (A) / polyester resin (B) / polycarboxylic acid compound (C) = 30 / 69.7 / 0.3% by weight. A parison and a stretch blow bottle were obtained under the same conditions as in Example 1 except that the composition ratio was 7% by weight and 83.3% by weight of the polyester resin (E). The average dispersion particle diameter of the polyamide resin (A) in the parison body is 0.24 μm, the obtained bottle is Haze 6.2% / 300 μm, YI 9.2 in the body, and the oxygen permeability is 0.020 cc. /Bottle·day·0.21 atm. The obtained bottle was less colored and had good transparency and gas barrier performance. The results are shown in Table 1.

<Comparative Example 1>
Polyamide resin (A) / polyester resin (B) / polycarboxylic acid compound (C) = 5 / 94.95 / 0.05% by weight of dry blend, and parison under the same conditions as in Example 1. A stretch blow bottle was obtained. The average dispersion particle size of the polyamide resin (A) in the obtained parison barrel is 0.40 μm, the obtained bottle is Haze 13.4% / 300 μm, YI 13.9 in the barrel, and the oxygen permeability is 0.020 cc / bottle · day · 0.21 atm. The results are shown in Table 2.

<Comparative example 2>
Except for using a polyethylene terephthalate resin (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT523C (inherent viscosity 0.72 dl / g, melt viscosity 200 Pa · sec, moisture 150 ppm)) as the polyester resin (E). Under the same conditions as in Example 1, a parison and a stretch blow bottle were obtained. The average dispersion particle diameter of the polyamide resin (A) in the parison body is 0.39 μm, the obtained bottle has a haze of 13.0% / 300 μm, YI of 10.8, and an oxygen transmission rate of 0.020 cc. /Bottle·day·0.21 atm. The results are shown in Table 2.

<Comparative Example 3>
Polyester terephthalate resin (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT523C (intrinsic viscosity 0.72 dl / g, melt viscosity 200 Pa · sec, moisture 150 ppm)) as polyester resins (B) and (E) A parison and a stretch blow bottle were obtained under the same conditions as in Example 1 except that they were used. The average dispersion particle size of the polyamide resin (A) in the parison body is 0.44 μm, the obtained bottle has a haze of 13.8% / 300 μm, YI 11.2, and an oxygen permeability of 0.020 cc. /Bottle·day·0.21 atm. The results are shown in Table 2.

<Comparative example 4>
Polyamide resin (B) and (E) using polyamide MXD6 (Mitsubishi Gas Chemical Co., Ltd. MX nylon, grade: 6000, relative viscosity 2.10, melt viscosity 200 Pa · sec, moisture 400 ppm) as the polyamide resin (A) Example 1 except that polyethylene terephthalate resin (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT523C (inherent viscosity 0.72 dl / g, melt viscosity 200 Pa · sec, moisture 150 ppm)) was used. A parison and a stretch blow bottle were obtained under the same conditions. The average dispersion particle size of the polyamide resin (A) at the parison body is 0.53 μm, the obtained bottle has a haze of 14.7% / 300 μm, YI13.2, and an oxygen permeability of 0.020 cc. /Bottle·day·0.21 atm. The results are shown in Table 2.

<Comparative Example 5>
The composition ratio of the master batch (D) is polyamide resin (A) / polyester resin (B) / polycarboxylic acid compound (C) = 50 / 49.5 / 0.5 wt%, and the master batch (D) is 10 wt. % And a polyester resin (E) 90 wt%, except that the parison and stretch blow bottle were obtained under the same conditions as in Example 1. The average dispersion particle size of the polyamide resin (A) in the parison body is 0.42 μm, and the obtained bottle has a haze of 12.6% / 300 μm, YI12.4, and an oxygen permeability of 0.022 cc. /Bottle·day·0.21 atm. The results are shown in Table 2.

<Comparative Example 6>
The composition ratio of the master batch (D) is polyamide resin (A) / polyester resin (B) / polycarboxylic acid compound (C) = 80 / 19.2 / 0.8% by weight. A parison and a stretch blow bottle were obtained under the same conditions as in Example 1 except that the composition ratio was 25% by weight and the polyester resin (E) 93.75% by weight. The average dispersion particle size of the polyamide resin (A) in the parison body is 0.39 μm, the obtained bottle has a haze of 13.1% / 300 μm, YI of 13.5, and an oxygen transmission rate of 0.021 cc. /Bottle·day·0.21 atm. The results are shown in Table 2.

  The molded body using the polyester resin composition of the present invention is excellent in appearance and mechanical properties such as gas barrier properties and transparency, and is very useful as a packaging material for foods, beverages, chemicals, electronic parts and the like. And its industrial value is high.

Claims (12)

Polyamide resin (A) in which 70 mol% or more of the diamine structural unit is derived from metaxylylenediamine and 70 mol% or more of the dicarboxylic acid structural unit is derived from adipic acid, 70 to 70% of the dicarboxylic acid structural unit 59 to 89.95% by weight of a polyester resin (B) in which mol% or more is derived from an aromatic dicarboxylic acid and 70 mol% or more of the diol constituent unit is derived from an aliphatic diol, and aromatic trivalent carboxylic acid and fat At least one polyvalent carboxylic acid compound (C) selected from the group consisting of a cyclic trivalent carboxylic acid, an aromatic divalent carboxylic acid, an alicyclic divalent carboxylic acid, and an acid anhydride of the carboxylic acid; After obtaining a master batch (D) in which 05 to 1 wt% (the total of wt% is 100 wt%) is previously melt-kneaded, the master batch (D), By melting and kneading the polyester resin (E) in which 70 mol% or more of the carboxylic acid structural unit is derived from the aromatic dicarboxylic acid and 70 mol% or more of the diol structural unit is derived from the aliphatic diol, a polyamide resin (A ) 2 to 30% by weight, polyester resins (B) and (E) in total 69.5 to 99.99% by weight, and polyvalent carboxylic acid compound (C) 0.01 to 0.5% by weight (% by weight) Is a method of producing a polyester resin composition comprising:
The following formulas (1) to (2):
100 ≦ a ≦ 250 (1)
0.1 ≦ a / b ≦ 0.5 (2)
(In the above formula, a and b are as follows.
a is the melt viscosity (Pa · sec) of the master batch (D) measured under the conditions of 280 ° C. and a shear rate of 100 / sec; b is the melt viscosity (Pa · sec) of the polyester resin (E) measured under the above conditions. is there)
The manufacturing method of the polyester resin composition characterized by satisfy | filling. The polyamide resin (A) was obtained by further solid-phase polymerization of a melt-polymerized polyamide resin having a relative viscosity of 1.83 to 2.28 obtained from diamine and dicarboxylic acid, and having a relative viscosity of 2.30 to 4. 2. The polyester resin composition according to claim 1, wherein the polyester resin composition is a 20 solid phase polymerization polyamide resin. The method for producing a polyester resin composition according to claim 1 or 2, wherein the polyamide resin (A) has a melt viscosity of 100 to 2000 Pa · sec under conditions of 280 ° C and a shear rate of 100 / sec. The method for producing a polyester resin composition according to any one of claims 1 to 3, wherein the melt viscosity of the polyamide resin (A) / the melt viscosity of the polyester resin (B) is 0.3 to 1.2. The method for producing a polyester resin composition according to any one of claims 1 to 4, wherein the polyamide resin (A) is polymetaxylylene adipamide. The intrinsic viscosity (value measured at 25 ° C. in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 60/40 weight ratio) of the polyester resin (B) is 0.5 to 2.0 dl / g. The manufacturing method of the polyester resin composition in any one of Claims 1-5. The intrinsic viscosity of the polyester resin (E) (phenol / 1,1,2,2-tetrachloroethane = a value measured at 25 ° C. in a 60/40 weight ratio mixed solvent) is 0.5 to 2.0 dl / g. The manufacturing method of the polyester resin composition in any one of Claims 1-6. Polyester resin (B) is polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polybutylene terephthalate resin and polyethylene-2,6-naphthalene dicarboxylate resin The method for producing a polyester resin composition according to claim 1, wherein the polyester resin composition is one or more selected from the group consisting of: Polyester resin (E) is polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polybutylene terephthalate resin and polyethylene-2,6-naphthalene dicarboxylate resin The method for producing a polyester resin composition according to claim 1, wherein the polyester resin composition is one or more selected from the group consisting of: The polyester resin composition according to any one of claims 1 to 9, wherein the polyvalent carboxylic acid compound (C) is at least one selected from phthalic acid, phthalic anhydride, trimellitic acid and trimellitic anhydride. Law. The polyester resin composition obtained by the manufacturing method in any one of Claims 1-10. The molded object obtained by shape | molding the polyester resin composition of Claim 11.