JPH06172549A - Thermoplastic polyester resin composition and production of ultraviolet-barrier container - Google Patents

Abstract

PURPOSE:To provide a plastic container which is excellent in transparency, ultraviolet-barrier properties, and surface smoothness and contains a reduced amt. of a residual aldehyde. CONSTITUTION:A thermoplastic polyester resin compsn. is obtd. by blending a thermoplastic polyester (A) which is obtd. from a dicarboxylic acid component contg. at least 75mol% 2,6-naphthalenedicarboxylic acid and a diol component contg. at least 75mol% ethylene glycol and in which the sum of dicarboxylic acid units other than 2,6-naphthalenedicarboxylic acid units and glycol units other than ethylene glycol units is 5-30mol% with a thermoplastic polyester (B) which is obtd. from a dicarboxylic acid component contg. at least 80mol% terephthtalic acid and a diol component contg. at least 80mol% ethylene glycol in such a ratio of A to B that 2,6-naphthalenedicarboxylic acid units account for 0.1-20mol% of the total amt. of the dicarboxylic acid units. The compsn. is blow-molded under monoaxial stretching to give an ultraviolet-barrier container.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plastic container which is excellent in transparency, UV barrier property, surface smoothness of a container, and has a reduced amount of residual aldehyde, and a thermoplastic polyester resin as a raw material for the container. It relates to a formulation.

[0002]

2. Description of the Related Art Polyethylene naphthalate (PEN) has attracted attention as a plastic material having transparency and an excellent barrier property against ultraviolet rays. PEN can block ultraviolet rays in the 320 to 380 nm region, which cannot be blocked by polyethylene terephthalate (PET), and is also a material excellent in barrier properties against gases such as oxygen and water vapor.

It is well known that PEN has an ultraviolet barrier property, and for example, JP-A-50-122549 also discloses that PET has PEN.
Of 0.1 to 10% by weight of polyester film having excellent weather resistance is described. In addition, PEN copolymer, PE
Containers using N blends are also known, for example, RESE
ARCH DISCLOSURE, 29410, 714-719 (1988) and RESEARCH
DISCLOSURE, 29484, 807-814 (1988) and the like describe containers with various copolymerization amounts and blending amounts. In the manufacture of an ultraviolet barrier plastic container using such PEN, the wavelength of the ultraviolet rays to be blocked differs slightly depending on the content of the PEN unit as shown below, and the wavelength range of the ultraviolet rays to be blocked also depends on the type of contents. Since it will be different, P depending on the type of contents during molding
It is most convenient if containers with different EN contents can be produced, and in that respect, it can be said that blending PET with a necessary amount of PEN is preferable to using a copolymer. Then, in order to cope with the production of a wide range of containers having different PEN contents, it is preferable to use a polymer having a high PEN content as the polymer to be blended.

(Example) PET-PEN copolymer PEN content 1 mol% ... blocks UV light of 360 nm or less 10 mol% ... blocks UV light of 370 nm or less 100 mol% ... blocks UV light of 380 nm or less When PEN is blended with a thermoplastic polyester resin whose unit is PET in a hopper at the time of molding without pre-kneading, it is difficult for PEN crystals to completely melt, and the smoothness of the surface of the molded body is impaired.

Further, when a thermoplastic polyester having an amorphous composition is selected as a component to be blended, the surface smoothness of the molded article can be maintained, but since it is amorphous, solid-phase polymerization cannot be adopted during the production of the resin, and the There has been a problem that the amount of residual aldehyde slightly increases, and when used as a material for food containers, the odor and taste of the contents are adversely affected.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a 2,6-naphthalenedicarboxylic acid component and an ethylene glycol component are contained in a specific amount or more and other acid components are included. And a thermoplastic polyester (A) in which the sum of the diol components is specified within a specific range, and a thermoplastic polyester (B) containing a terephthalic acid component and an ethylene glycol component in a specific amount or more at a specific ratio. Using a plastic polyester resin blend,
It has been found that a plastic container having excellent transparency, UV barrier property, surface smoothness of the container, and reduced residual aldehyde content can be obtained by stretch blow molding in at least one axial direction, thus completing the present invention. . That is, in the present invention, 75 mol% or more of the dicarboxylic acid component is 2,6-naphthalenedicarboxylic acid, 75 mol% or more of the diol component is ethylene glycol, and
When the mol% of acid components other than 2,6-naphthalenedicarboxylic acid is a% and the mol% of diol components other than ethylene glycol in the diol component is b%, the sum of a and b is
(1) 5 ≦ a + b ≦ 30 A thermoplastic polyester (A) in a range satisfying (1), and 80 mol% or more of dicarboxylic acid component is terephthalic acid,
A thermoplastic polyester (B) in which 80 mol% or more of the diol component is ethylene glycol, and the 2,6-naphthalenedicarboxylic acid component is 0.1 to 20 mol% of the total dicarboxylic acid component.
To provide a thermoplastic polyester resin blend prepared by blending so as to obtain a thermoplastic resin composition, and a method for producing an ultraviolet barrier container characterized by stretch blow-molding the thermoplastic polyester resin blend in at least one axial direction. is there.

Thermoplastic polyester (A) used in the present invention
Is at least 75 mol% of the dicarboxylic acid component is 2,6-naphthalenedicarboxylic acid, at least 75 mol% of the diol component is ethylene glycol, and the dicarboxylic acid component is 2,6
-Mole% of acid components other than naphthalene dicarboxylic acid
%, And the mol% of the diol component other than ethylene glycol in the diol component is b%, the sum of a and b is
(1) 5 ≦ a + b ≦ 30 (1) A thermoplastic polyester in the range. a
If + b is less than 5, unmelted crystals are likely to be contained in the molded product during container molding, resulting in poor surface smoothness.
When it exceeds 30, the crystallinity is considerably impaired and it becomes difficult to reduce the residual aldehyde by solid-state polymerization.

As the dicarboxylic acid component of the thermoplastic polyester (A) other than 2,6-naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, 1,5-, 1,6-, 1,7-,
2,7-Naphthalenedicarboxylic acid, phthalic acid, cyclohexanedicarboxylic acid, dibromoisophthalic acid, sodium-sulfoisophthalic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketonedicarboxylic acid, diphenoxyethanedicarboxylic acid, phenyl Aromatic dicarboxylic acid such as dioxydiacetic acid, adipic acid, sebacic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, undecadioic acid, dodecadioic acid, etc. A mixture may be mentioned.

The diol components other than ethylene glycol of the thermoplastic polyester (A) include trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, propylene glycol and neopentyl. Aliphatic glycols such as glycol, diethylene glycol and polyethylene glycol, alicyclic glycols such as cyclohexanedimethanol, o, m, p-xylylene glycol, 2,2-bis (4
Aromatic glycols such as -hydroxyethoxyphenyl) propane, ethylene oxide adduct of 2,2-bis (4-hydroxyethoxyphenyl) propane, and propylene oxide adduct are used alone or as a mixture of two or more kinds.

The thermoplastic polyester (B) used in the present invention is 80 mol% or more of the dicarboxylic acid component, preferably
90 mole% or more is terephthalic acid and 80% of diol component
Ethylene glycol is at least mol%, preferably at least 90 mol%.

The dicarboxylic acid component other than terephthalic acid of the thermoplastic polyester (B) includes isophthalic acid, 1,5
-, 1,6-, 1,7-, 2,6-, 2,7-naphthalenedicarboxylic acid, phthalic acid, cyclohexanedicarboxylic acid, dibromoisophthalic acid, sodium-sulfoisophthalic acid,
Diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, diphenoxyethane dicarboxylic acid,
Aromatic dicarboxylic acids such as phenylenedioxydiacetic acid, adipic acid, sebacic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, undecadioic acid,
Aliphatic dicarboxylic acid such as dodecadioic acid or two
Mixtures of more than one species are mentioned.

Examples of the diol component other than ethylene glycol of the thermoplastic polyester (B) include trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, propylene glycol and neopentyl. Aliphatic glycols such as glycol, diethylene glycol and polyethylene glycol, alicyclic glycols such as cyclohexanedimethanol, o, m, p-xylylene glycol, 2,2-bis (4
-Hydroxyethoxyphenyl) propane, an ethylene glycol adduct of 2,2-bis (4-hydroxyethoxyphenyl) propane, a propylene oxide adduct, and the like, alone or in a mixture of two or more kinds.

Thermoplastic polyester (A) in the present invention
And (B) are each prepared by a known production method such as a polycondensation reaction with the dicarboxylic acid component and the diol component or a transesterification reaction using the short chain alkyl ester (dimethyl ester etc.) of the dicarboxylic acid component and the diol component. Obtainable. Further, in addition to the above dicarboxylic acid component and diol component, a hydroxycarboxylic acid such as glycolic acid, hydroxybenzoic acid or hydroxynaphthoic acid, or a diphenol such as hydroquinone, resorcinol, dihydroxydiphenyl or dihydroxydiphenyl ether may be copolymerized.

The thermoplastic polyester resin composition of the present invention comprises the above-mentioned thermoplastic polyester (A) and thermoplastic polyester (B), wherein the 2,6-naphthalenedicarboxylic acid component is 0.1 to 20% of the total dicarboxylic acid component. It is blended so as to be mol%. If the content of 2,6-naphthalenedicarboxylic acid component in the total dicarboxylic acid component of the thermoplastic polyester resin compound is less than 0.1 mol%, the effect of UV barrier property is small, and if it is 20 mol%, the effect of UV barrier property is small. It is enough.

Thermoplastic polyester used in the present invention
Both (A) and thermoplastic polyester (B) are at 25 ° C in a mixed solvent of phenol / tetrachloroethane (weight ratio 6/4).
It is preferable that the intrinsic viscosity measured in step 1 is 0.5 dl / g or more. When the intrinsic viscosity is less than 0.5 dl / g, the mechanical properties of the obtained container are deteriorated, which is not preferable. Both the thermoplastic polyester (A) and the thermoplastic polyester (B) used in the present invention are preferably subjected to solid-state polymerization at the time of production for the purpose of reducing the amount of residual aldehyde.

In the present invention, the container is preferably formed by stretch blow molding in at least one axial direction, usually P.
Biaxial stretch blow molding used when manufacturing ET containers can be utilized. In addition, a method called a cold parison method in which a preform (preformed body) is once taken out and then stretch blow molded in a separate step, and a method called a hot parison method in which a preform making step and a stretch blow molding step are continuous Any of the methods can be employed. Further, various additives such as a colorant, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant and the like can be added to the polyester resin composition of the present invention as required.

[0017]

The present invention is described in detail below with reference to examples, but these examples do not limit the present invention in any way. The test methods used in Examples and Comparative Examples are as follows. -UV blocking property A part of the sample was cut out from the container, and the wavelength of the transmitted light was measured using a spectrophotometer UV-265FW manufactured by Shimadzu Corporation to evaluate the blocking property. -Amount of residual aldehyde A part of the sample was cut out from the container, cooled with liquid nitrogen, finely ground, and the powder was put in a gas chromatograph to determine the amount of acetaldehyde released. -Surface smoothness The surface smoothness of the container was evaluated according to the following three grades. ○: No unevenness is observed. Δ: Slight unevenness is recognized. X: Unmelted resin is clearly observed and unevenness is also observed.

Examples 1 to 3 Polyethylene terephthalate-polyethylene naphthalate (molar ratio 1: 9) copolymer (intrinsic viscosity) which was solid-phase polymerized as a thermoplastic polyester (A) at 230 ° C. under reduced pressure for 15 hours.
0.73 dl / g, residual aldehyde content 2.3 ppm), and polyethylene terephthalate homopolymer (thermoplastic polyester (B) solid-state polymerized under reduced pressure for 15 hours at 230 ° C. (intrinsic viscosity 0.79 dl / g, residual aldehyde content 1.8 ppm)) To 1: 1
Compounded in a molar ratio of 0, 1:20, 1: 100, outer diameter 27mm,
A preform having a length of 115 mm and a wall thickness of 3 mm was molded by an injection molding method. The molding condition at that time is that the setting value of the cylinder temperature is
The temperature was set to 260 to 280 ℃, and the mold temperature was set to 20 to 40 ℃. Biaxially stretch blow molding was carried out at 110 ℃, and the volume was 600ml.
A cylindrical container having a body diameter of 60 mm, a height of 220 mm and a mouth diameter of 27 mm was molded. The molding machine is Nissei ASB Machine Co., Ltd.
An injection blow molding machine was used. The resulting container was evaluated for UV blocking property, residual aldehyde amount and surface smoothness. The composition of the used thermoplastic polyester resin compound is shown in Table 1, and the evaluation results are shown in Table 2.

Example 4 As a thermoplastic polyester (A), a polyethylene terephthalate-polyethylene naphthalate (molar ratio 1: 4) copolymer (intrinsic viscosity) which was solid-state polymerized at 210 ° C. under reduced pressure for 15 hours.
Molding was carried out in the same manner as in Example 1 except that 0.70 dl / g and residual aldehyde amount of 3.5 ppm) were used, and the resulting container was evaluated for UV blocking property, residual aldehyde amount and surface smoothness. The composition of the thermoplastic polyester resin compound used is shown in Table 1.
The evaluation results are shown in Table 2.

Comparative Examples 1 to 3 Polyethylene naphthalate homopolymer (intrinsic viscosity 0.78 dl / g, residual aldehyde amount 1.5 ppm) solid-phase polymerized under reduced pressure at 240 ° C. for 15 hours was used as the thermoplastic polyester (A). Molding was performed in the same manner as in Examples 1 to 3. However,
The cylinder temperature was 270 to 290 ° C. The resulting container was evaluated for UV blocking property, residual aldehyde amount and surface smoothness. The composition of the used thermoplastic polyester resin compound is shown in Table 1, and the evaluation results are shown in Table 2.

Comparative Example 4 As a thermoplastic polyester (A), a polyethylene terephthalate-polyethylene naphthalate (molar ratio 1: 1) copolymer (intrinsic viscosity 0.70 dl / g, residual aldehyde amount 22.1 pp)
Molding was performed in the same manner as in Example 1 except that m) was used. Since this copolymer is amorphous, the amount of aldehyde could not be reduced by solid phase polymerization. The resulting container was evaluated for UV blocking property, residual aldehyde amount and surface smoothness. The composition of the used thermoplastic polyester resin compound is shown in Table 1, and the evaluation results are shown in Table 2.

[0022]

[Table 1]

[0023]

[Table 2]

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Claims (2)

[Claims] 1. 75 mol% or more of the dicarboxylic acid component is 2,6
-Naphthalenedicarboxylic acid, 75 mol% or more of the diol component is ethylene glycol, and a mol% of the acid component other than 2,6-naphthalenedicarboxylic acid in the dicarboxylic acid component is a%, and other than ethylene glycol in the diol component is When the mol% of the diol component is b%, the thermoplastic polyester (A) having a sum of a and b within the range of the following formula (1) 5 ≦ a + b ≦ 30 (1) and 80% of the dicarboxylic acid component More than mol% is terephthalic acid,
A thermoplastic polyester (B) in which 80 mol% or more of the diol component is ethylene glycol, and the 2,6-naphthalenedicarboxylic acid component is 0.1 to 20 mol% of the total dicarboxylic acid component.
A thermoplastic polyester resin compound prepared by blending so that 2. A method for producing a UV barrier container, which comprises subjecting the thermoplastic polyester resin composition according to claim 1 to stretch blow molding in at least one axial direction.