KR940003185B1 - Polyester resin composition and hollow molded articles thereof - Google Patents

Abstract

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Description

Polyester blow molding

The present invention relates to a polyester hollow molded article having excellent gas barrier properties and transparency.

More specifically, the present invention relates to a polyester hollow molded article having excellent gas barrier properties and transparency by blending a thermoplastic polyester resin, a metha xylene group-containing polyamide resin, and a compatibilizer linking the two components.

Conventionally, thermoplastic polyester resin mainly composed of polyethylene terephthalate is made of various containers, films, sheets, etc. by paying attention to the excellent mechanical properties, gas barrier properties, chemical resistance, compensatory properties, transparency, hygiene, and safety of the material. It has been widely used as a packaging material. In particular, in recent years, due to the improvement of blow molding technology, in particular, biaxial stretch blow molding technology, the use as a hollow container such as a bottle or a can is remarkable.

However, a biaxially oriented container composed of a thermoplastic polyester resin mainly composed of polyethylene terephthalate does not have perfect performance, and in particular, a container such as a food or a medicine for which the contents to be filled require high gas barrier properties. It was unsuitable for lack of gas barrier to oxygen.

Conventionally, in order to improve the gas barrier property of a plastic container, resin which is excellent in gas barrier property, such as polyvinyl alcohol (Japanese Unexamined-Japanese-Patent No. 54-114572), and vinylidene chloride-type resin (Japanese Unexamined-Japanese-Patent No. 56-155759) The container which laminated | stacked or coated the ethylene vinyl alcohol resin (the Unexamined-Japanese-Patent No. 56-77143) is known. However, the interlayer adhesion is weak due to lack of compatibility with the polyester resin, the bonding strength, the reaction force, and the like, the mechanical strength is insufficient as the container, or permeate gas is retained between the layers. In addition, it has disadvantages such as weak water resistance and gas barrier durability. In addition, attempts have been made to obtain a container having excellent gas barrier properties by mixing gas barrier resins with thermoplastics. As gas barrier resins, ethylene-vinyl acetate copolymer saponification, styrene-acrylonitrile copolymers, and the like are known. In this case, too, water resistance is poor, or stretchability is insufficient, the pulsator is devitrified, lacks transparency, gas barrier properties are insufficient, etc., and the results are not yet satisfactory.

In addition, attempts have been made to improve gas barrier properties by mixing methacrylic group-containing polyamide resins with thermoplastic polyester resins (see Japanese Patent Application Laid-Open No. 52-73966), but due to poor compatibility, they lack transparency. It has a problem that the drawability is deficient and the barrier property is greatly reduced at the time of moisture absorption, and its use is limited.

The present inventors have diligently studied to solve the above problems, and as a result, they do not impair the excellent mechanical properties of the thermoplastic polyester resin at all, and do not impair the transparency even when mixed with each other. It has been found that the hollow molded article having no transparency is affected by the moisture component is obtained by the addition of a specific modified copolymerized polyester as a methacrylic group-containing polyamide resin and a compatibilizer, and finally the present invention has been completed. That is, the present invention relates to a thermoplastic polyester (A) in which at least one layer has a main repeating unit of ethylene terephthalate in a hollow molded product consisting of a single layer or a multilayer, a methacrylic group-containing polyamide (B) and an aliphatic dicarboxylic acid. Modified copolymerized polyester (C) obtained by grafting unsaturated carboxylic acid or derivatives thereof to a co-polyester having at least one selected from cyclohexanedimethanol and hydrogenated dimethyl terephthalate as one component. It is a polyester hollow molded object characterized in that it contains.

Thermoplastic polyester which is (A) component of this invention is a terephthalic acid, an isophthalic acid, diphenyl ether 4, 4'- dicarboxylic acid, naphthalene 1, 4- or 2, 6- dicarboxylic acid, adi, as an acid component. Finic acid, sebacic acid, decane 1, 10-dicarboxylic acid, hexahydroterephthalic acid, ethylene glycol, propylene glycol, 1, 4-butanediol, neopentylglycol, diethylene glycol, cyclohexanedimethanol, 2, 2 as glycol components '-Bis (4-hydroxyphenyl) propane, 2,2'-bis (4-hydroxyethoxyphenyl) propane or oxy acid is obtained as P-oxybenzoic acid, P-hydroethoxy benzoic acid, etc. In the present invention, a polyolefin having a main repeating unit of ethylene terephthalate having 80 mol% or more of the acid component, preferably 90 mol% or more, is terephthalic acid and 80 mol% or more, preferably 90 mol% or more, of the glycol component is ethylene glycol. Ester is preferred.

The intrinsic viscosity of the thermoplastic polyester of the present invention is a value of 0.55 or more, more preferably 0.65 to 1.4. If the intrinsic viscosity is less than 0.55, parison, which is a precursor of the container, is difficult to obtain in a transparent amorphous state, and the mechanical strength of the obtained container is also insufficient.

Moreover, the metaxylylene group containing polyamide which is (B) component used for this invention is a mixed xylyl containing methaxylylenediamine or methaxylylenediamine and 30% or less of paraxylylenediamine in whole quantity. And polymers containing at least 70 mol% in the molecular chain of the rediamine and a structural unit produced from α, ω-aliphatic dicarboxylic acid having 4 to 10 carbon atoms.

Examples of these polymers include homopolymers such as polymethacrylyleneadipamide, polymethaxylylene sebacamide, polymethaxylylenesuberamide and the like and methacrylic / paraxylylene adipamide copolymers, methaks Copolymers such as silylene / paraxylylenepimeramide copolymers, metaxylylene / paraxylyleneazeramide copolymers and components of homopolymers or copolymers thereof and aliphatic diamines such as hexamethylenediamine, pipera Alicyclic diamines such as dean, aromatic diamines such as para-bis (2-aminoethyl) benzene, aromatic dicarboxylic acids such as terephthalic acid, lactams such as ε-caprolactam, ω-aminocarboxes such as r-aminoheptanoic acid The copolymer which copolymerized the acid, aromatic aminocarboxylic acid, such as para-aminomethyl benzoic acid, etc. are mentioned.

In the copolymer, paraxylylenediamine is 30% or less with respect to all xylylenediamine, and the structural units formed from xylylenediamine and aliphatic dicarboxylic acid are at least 70 mol% or more in the molecular chain. to be.

The metha xylylene group-containing polyamide (hereinafter abbreviated as MXD ₆ resin) itself is inherently vulnerable in an amorphous state, so the relative viscosity usually needs to be 1.5 or more, preferably 2.0 to 4.0.

The modified co-polyester of the component (C) in the present invention has molecular compatibility with the thermoplastic polyester to finely disperse the MXD ₆ resin, and significantly improves the transparency of the molded article obtained from the polyester resin composition. Specifically, 60 mol% or more of the acid component, preferably 70 mol% or more, is terephthalic acid, and 30 mol% or more, preferably 50 mol% or more, of the glycol component has 2 to 12 carbon atoms, preferably 2 to 4 carbon atoms. It is an alkylene glycol, and is unsaturated carbon in co-polyester which has at least 1 sort (s) of compound chosen from aliphatic dicarboxylic acid, such as sebacic acid, adipic acid, dodecanedioic acid, or cyclohexane dimethanol, or hydrogenated dimethyl terephthalate as one component. It is obtained by grafting an acid or a derivative thereof.

In addition, the aliphatic dicarboxylic acid, which is the copolymerization component, is preferably 5 to 50 mol%, particularly 10 to 30 mol%, based on the total acid component, and the hydrogenated dimethyl terephthalate is 5 to 60 mol%, particularly 10 to 10% based on the total acid component. 40 mol% is preferable, and cyclohexane dimethanol is 5 to 70 mol%, especially 20-50 mol% with respect to all the glycol components. The intrinsic viscosity of the obtained copolyester is preferably 0.40 or more, and more preferably 0.50 to 1.4.

Moreover, maleic acid, maleic anhydride, fumaric acid, itaconic acid, acrylic acid, crotonic acid, etc., and its anhydride etc. can be mentioned as unsaturated carboxylic acid or its derivative graft | grafted to a copolyester.

In addition, the said molecular compatibility means that the kneaded composition is mixed by molecular order and the glass transition point obtained by DSC or viscoelasticity measurement is substantially one.

Although the compounding quantity of (B) and (C) component in (A) component in this invention differs according to the kind of (C) component, the compounding quantity of (C) component is (B) The component is 1 to 100 parts by weight, preferably 5 to 60 parts by weight, and the mixing of the component (B) and the component (C) is 95: 5 to 5:95, particularly 70:30 to 40:60 Do.

In the present invention, additives such as antioxidants, ultraviolet absorbers, antistatic agents and transparent coloring agents can be added as necessary.

Next, the method of mixing the above-mentioned (A) to (C) component is not specifically limited, It is performed by arbitrary methods. For example, each component is obtained by mechanically kneading with an extruder, a roll mill, a Benbury mixer, or the like. Also after mixing the pre-modified and the MXD ₆ resin polymerized polyester may be a multi-stage kneading, such as to blending the thermoplastic polyester component.

As a method for obtaining the gas barrier hollow molded product of the present invention, a method of forming dry mixture of the above-mentioned concentrations (A) to (C), and directly molding the hollow body molding machine, or melt-kneading each component in an extruder to produce a mixed composition pellet And the method of molding the pellets with a blow molding machine.

The molding by the blow molding machine can be carried out without any other difference from the blow molding of the conventional polyester resin. For example, extrusion blow molding or injection blow molding, commonly referred to as direct blow, is a method in which a parison is blow molded by a press body while not sufficiently cooled after injection molding, or a molding called biaxial stretch blow molding. After making the user opening parison by injection molding or extrusion molding, the parison is stretched by a drawing blower to adjust the temperature to an appropriate temperature, for example, 70 to 150 ° C, and the axial stretching by the stretching rod, and the compressor body. The blow molding of the circumferential direction by the simultaneous or in turn is used.

In the hollow molded product of the present invention, (A) thermoplastic polyester and (C) modified copolyester have molecular compatibility, and the orientation by stretching when the Tg of each component of (A), (B) and (C) is almost the same. Since crystallization is sufficiently organic, it is possible to remarkably improve oxygen gas barrier properties without any damage to the excellent mechanical properties of the thermoplastic polyester.

EXAMPLE

Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited by this.

And the measuring method of the main characteristic measured by this invention is shown below. However, oxygen permeation was carried out with the bottle, and other items were carried out using test pieces cut from the main eastern part of the bottle.

(1) intrinsic viscosity (η) of polyester; It measured at 30 degreeC using the phenol / tetrachloroethane = 6/4 (weight ratio) mixed solvent.

(2) ηrel of MXD ₆ resin; Relative viscosity measured at 25 ° C by dissolving 1 g of resin in 100 ml of 96 wt% sulfuric acid.

(3) transparency and haze; Using Haze-Meta MODEL TC-H III manufactured by Tokko Denshokusha Co., Ltd., the following formula was calculated according to JIS-K6714.

Transparency = T ₂ / T ₁ × 100 (%)

×100(%)Haze =

× 100 (%)

T ₁ : incident light amount

T ₂ : total light transmittance

T ₃ : amount of scattered light by the device

T ₄ : amount of scattered light by the device and sample

(4) oxygen permeation amount; It measured at 20 degreeC as the permeation amount per 1000 cc bottle by the oxygen permeation measuring device OX-TRAM 100 by the US MODERN CONTROLS company.

(5) saddle characteristics; Tensile, manufactured by Toyo Bouldwin, Inc., was used for thin, roughly shaped specimens of 10 mm in width, and the tensile strength and elongation at break were applied under conditions of 50 mm between the chuck and 50 mm / min of tensile speed. It measured (23 degreeC).

[Examples 1 to 6 and Comparative Examples 1 to 3]

(C) As a component, 0.5 parts by weight of maleic anhydride and 0.2 parts by weight of dichmiyl phosphate are mixed with 100 parts by weight of copolyester (terephthalic acid / ethylene glycol / cyclohexanedimethanol = 100/65/35), followed by 240 under a nitrogen atmosphere. Melt kneading was carried out with a 30 nm φ biaxial extruder at 占 폚, and pelletized after extrusion cooling to obtain a modified copolymerized polyester having a graft ratio of maleic anhydride of 1.5 mol%.

Next, a polyethylene terephthalate (abbreviated as PET) of (η) = 0.80 is used as the polyester (A) component, and polymethacrylylene adipamide of ηrel = 2.2 is used as the MXD ₆ resin of the component (B). Each component was kneaded with the modified (C) -modified copolyester in the proportions shown in Tables 1 and 2 to obtain pellets, and the injection molding machine of M-100 type manufactured by Meiki Seisakusho Co., Ltd. was used. The user parison of 25 mm in outside diameter, 130 mm in length, and 4 mm in thickness was formed, respectively. The parison is inserted into a parison fitting end with a bicycle driving device, and heated until the surface temperature of the parison reaches 110 ° C while rotating in an open with a far infrared heater. It was. After this, the parison was transferred into the blow mold, and blow molded under the conditions of the movement speed of the stretching rod 22 cm / sec and the compressor body pressure 20 kg / cm 2. A hollow bottle in the shape of a beer bottle was obtained. The performance of these containers is shown in Tables 1 and 2.

TABLE 1

As apparent from Table 1, it can be seen that the hollow molded product of the present invention significantly improved transparency and further improved gas barrier properties. In addition, the haze value is 15, and the apparent transparency of the bottle changes significantly.

TABLE 2

As apparent from Table 2, it can be seen that the hollow molded product of the present invention has greatly improved the gas barrier and transparency at the time of moisture absorption.

[Examples 7 to 9 and Comparative Examples 4 to 6]

In Example 3, the molded object was obtained like Example 3 except having used the thing of the composition shown in Table 3 as (C) modified copolyester. The results are written together in Table 3.

TABLE 3

TPA: terephthalic acid AA: adipic acid,

IPA: isophthalic acid EG: ethylene glycol

H ₆ -DMT: Hydrogenated dimethyl terephthalic acid CHDM: Cyclohexanedimethanol

As apparent from Table 3, it can be seen that the transparency and the haze are considerably lowered when using a component (C) which is not modified with maleic anhydride.

As described above, the hollow molded article of the present invention having such a structure is excellent in transparency, gas barrier properties, and mechanical properties, and has a very high durability as a container which is hardly affected by moisture (water) as the effect is demonstrated in the examples. will be.

Claims (1)

In the hollow molded product consisting of a single layer or a multilayer, a methacrylic group-containing polyamide (B) and an aliphatic dicarboxylic acid and cyclohexane dimethanol are contained in a thermoplastic polyester (A) in which at least one layer has a main repeating unit of ethylene terephthalate. And a modified copolyester (C) grafted with unsaturated carboxylic acid or derivatives thereof in a copolyester having at least one selected from hydrogenated dimethyl terephthalate as one component. Molded body.