JPH11217427A - Polyethylene naphthalate resin particulate matter, molded article and bottle comprising same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin particulate matter and molded article excellent in hue, especially resistance to discoloration when receiving ray. SOLUTION: A polyethylene naphthalate resin particulate matter comprises a naphthalene dicarboxylic acid as a main acid component and ethylene glycol as a main glycol component and the resin particulate matter does not have a surface layer or the surface layer is 20 μm or less if the resin particulate matter has the surface layer. The resin particulate matter is preferably prepared by crystallizing a polyethylene naphthalate resin in an amorphous state by the amount of received UV ray with wavelengths of 220-300 nm reaches 3,000 mJ/cm<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene naphthalene dicarboxylate (hereinafter sometimes abbreviated as polyethylene naphthalate or PEN) resin used for molding packaging materials such as bottles and sheets. The present invention relates to a PEN resin having good moldability and excellent moldability.

[0002]

2. Description of the Related Art PEN has higher heat resistance than polyethylene terephthalate (hereinafter sometimes abbreviated as PET).
Because of its excellent basic properties such as gas barrier properties, chemical resistance and strength, it is useful for packaging materials such as bottles (containers) and sheet materials, and for films. However,
Amorphous PEN has a problem that a change in hue is large in long-term storage as compared with PET. PEN is PE
Compared with T, there is a problem that the transparency of the stretched molded product is lowered and the appearance is liable to be deteriorated when forming a bottle, a film or the like.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of PEN and to provide resin granules and moldings which are excellent in hue and moldability, and particularly excellent in discoloration resistance upon receiving light. Is to do. Furthermore, an object of the present invention is to obtain a resin granule having the above-mentioned properties suitable as a beverage bottle.

[0004]

That is, the present invention relates to a polyethylene naphthalate resin granule containing naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component. A particulate polyethylene naphthalate resin having an excellent hue, characterized in that it does not have a surface layer to be defined or has a surface layer of 20 μm or less even if it has one.

Hereinafter, the present invention will be described in detail. In the present invention, “main” means that it exceeds 70 mol%, preferably exceeds 80 mol%. Therefore, less than 30 mol% of other components may be contained as a copolymer or a mixture.

The polyethylene naphthalate resin containing naphthalenedicarboxylic acid as the main acid component and ethylene glycol as the main glycol component in the present invention is mainly intended for a homopolymer of polyethylene-2,6-naphthalenedicarboxylate. A portion (less than 30 mol%, preferably less than 20 mol%) of the 6,6-naphthalenedicarboxylic acid component may be replaced by another dicarboxylic acid component. As other dicarboxylic acid components, 2,7-, 1,5
-Or an aromatic dicarboxylic acid such as 1,7-naphthalenedicarboxylic acid or an isomer thereof, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, or the like; Alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid; adipic acid;
Aliphatic dicarboxylic acids such as sebacic acid and azelaic acid; and oxy acids such as p-β-hydroxyethoxybenzoic acid and ε-oxycaproic acid.

Further, a part of the ethylene glycol component (3
(Less than 0 mol%, preferably less than 20 mol%) may be replaced by other diol components. Other diol components include trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol,
Examples thereof include 2,2-bis (4′-β-hydroxyphenyl) propane and bis (4′-β-hydroxyethoxyphenyl) sulfonic acid.

In the present invention, the polyethylene naphthalate resin containing naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component contains 30 mol%, preferably up to 20 mol%, of the dicarboxylic acid component and the diol component, respectively. Allow the presence of polymerization components.

[0009] The polyethylene naphthalate resin of the present invention can be obtained by carrying out an esterification or transesterification reaction basically in the same manner as PET. The transesterification catalyst includes cobalt, manganese,
It is preferred to use calcium or magnesium compounds. More preferably, a prepolymer is obtained by performing a polycondensation reaction in the presence of a germanium catalyst and / or an antimony catalyst and a phosphorus compound, following the esterification or transesterification reaction. It is preferable that the amount of the germanium catalyst or the antimony catalyst is substantially in the range of 5 to 50 mmol% from the viewpoint of productivity and thermal stability.

Preferably, in the present invention, the obtained polyethylene naphthalate resin is crystallized at 170 to 230 ° C. in the form of amorphous resin granules, and is further solid-phased at a temperature lower than the melting temperature. Obtained by polymerization. The crystallization step is preferably performed before the thickness of the surface layer of the amorphous chip exceeds 20 μm. If the thickness of the surface layer is not more than 20 μm, little change in the hue of the resin after crystallization and solid phase polymerization is observed, and a good hue during production can be maintained during long-term storage.

Incidentally, the surface layer in the present invention is a layer which has changed color to yellow and is present near the surface of the resin granules. This surface layer mainly consists of the polymer itself degraded.
In the present invention, resin particles and chips are synonymous.

In the present invention, the crystallization of polyethylene naphthalate resin, in particular, the crystallization followed by solid phase polymerization,
It is preferred that the polyethylene naphthalate resin in an amorphous state to be subjected to the crystallization step has a light receiving amount of ultraviolet rays at 220 to 300 nm before reaching 3000 mJ / cm ² .
The polyethylene naphthalate resin of the present invention can be obtained by performing crystallization, particularly crystallization and solid phase polymerization, while satisfying these conditions. 220-300 nm
When the amount of ultraviolet ray received reaches 3,000 mJ / cm ² , the colored layer exceeds 20 μm, and it becomes impossible to maintain a good hue during production. The amount of received ultraviolet light is a measured value in the range of 220 to 300 nm, and the peak wavelength is 250 ± 10 nm.

The amount of acetaldehyde contained in the crystallized polyethylene naphthalate is preferably 10 ppm or less. If it exceeds 10 ppm, the amount of acetaldehyde in the total obtained by adjusting the amount of acetaldehyde to be regenerated when the molded article is formed is large, which undesirably gives an odor to the filling of the molded article.

The degree of crystallinity of the polyethylene naphthalate resin in the present invention is preferably 20% or more and 50% or less. When the degree of crystallinity is less than 20%, crystallization is insufficient and a change in hue during long-term storage cannot be suppressed. If the degree of crystallinity exceeds 50%, melting in ordinary injection molding and film molding is insufficient, and undissolved components remain, thereby impairing the appearance of the molded article.

The diethylene glycol unit contained in the polyethylene naphthalate resin of the present invention is 0.8 w
It is preferable that the content is not less than t% and not more than 3.0 wt%. When the content of the diethylene glycol component is less than 0.8 wt%, transparency is reduced due to crystallization in a stretching step such as bottle molding, and when it exceeds 3.0 wt%, thermal stability is reduced.

In the production process, the content of diethylene glycol is adjusted by adding the product produced in the production process and diethylene glycol. The time of the addition is preferably at the beginning of the transesterification reaction.

[0017]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. (1) Intrinsic viscosity (IV): Measured at 35 ° C. as a mixed solvent of tetrachloroethane: phenol = 4: 6.

(2) Col-b (hue): The amorphous polymer was heat-treated in a drier at 170 ° C. for 3 hours to be crystallized, and the crystalline polymer was left as it was without any pretreatment. The hue was measured with a CM-7500 color machine manufactured by Akihabara.

(3) Haze (transparency): 16
After drying at 0 ° C for 5 hours, injection molding machine 1 manufactured by Meiki Seisakusho
Using 00DM, a preform of 63 g was molded at a molding temperature of 305 ° C. and a molding cycle of 40 seconds, and was blow-stretched to obtain a bottle having an inner volume of 1.0 l and a body thickness of 400 μm.
The haze of the bottle body was measured with a turbidity meter manufactured by Nippon Denshoku Industries Co., Ltd.

(4) Diethylene glycol component content:
2 g of the polymer was decomposed with 10 ml of hydrazine and measured by gas chromatography.

(5) Crystallinity: The crystallinity of the resin particles was measured using a density gradient tube made of calcium nitrate.

(6) Measurement of the amount of ultraviolet rays: Measured with an ultraviolet intensity meter UM-10 manufactured by Minolta. The light receiving unit used was UM-250. The measurement wavelength is 220 to 300 nm, and the peak wavelength is 250 ± 10 nm.

(7) Acetaldehyde content: A chip or a molded product was freeze-pulverized and measured by a head space gas chromatograph.

(8) Thickness of Surface Layer The surface layer of the resin granules was measured by photographing a cut surface of the resin granules with a microscope.

Example 1 100 parts of 2,6-naphthalenedicarboxylic acid dimethyl ester (hereinafter, part by weight is abbreviated as part) and ethylene glycol (abbreviated as EG) 51
And 0.003 part of cobalt acetate tetrahydrate (0.012 m
mol), 0.014 parts (0.04 parts) of calcium acetate monohydrate.
8 mmol) and 0.044 parts (0.205 mmol) of magnesium acetate tetrahydrate were subjected to transesterification according to a conventional method using a transesterification catalyst.
l) After addition, trimethyl phosphate 0.05
7 parts (0.41 mmol) were added to terminate the transesterification reaction. Next, a polycondensation reaction was continuously performed under a high temperature and a high vacuum as usual, and then a strand type resin particulate (chip) was obtained. The intrinsic viscosity of the obtained polymer is 0.1.
5, Col-L / b = 83 / -3.0, diethylene glycol content was 1.5 wt%, and polymerization time was 70 minutes. No colored layer was observed by microscopic observation.

The obtained chip was exposed to sunlight for 4 hours. At this time, the amount of received ultraviolet light at 250 nm was 1600 mJ / cm.
^{Was 2} . When the chip after the treatment was observed with a microscope, the thickness of the colored layer was 2 μm, and Col-L / b = 83 / −2.
Nine.

Further, this prepolymer was crystallized by a conventional method and then subjected to solid-phase polymerization. The intrinsic viscosity of the obtained polymer is 0.65, the crystallinity is 37%, Col-L / b = 84.
/-2.0, the amount of acetaldehyde was 5 ppm.

The obtained chip was exposed to sunlight for 3 days. At this time, the amount of received ultraviolet light at 250 nm was 12,000 mJ / c.
m ² . When the chip after the treatment was observed with a microscope, the thickness of the colored layer was 10 μm, and Col-L / b = 84.1.
/-1.9.

Next, a preform was molded from the chip at a cylinder temperature of 300 ° C. using an injection molding machine. The hue of the preform was Col-L / b = 80 / -0.3.

From this preform, a bottle was formed by a blow molding machine. The haze of the bottle was 1%, no unmelted material.

Example 2 93 parts of 2,6-naphthalenedicarboxylic acid dimethyl ester, 6 parts of dimethyl terephthalate, 51 parts of ethylene glycol (abbreviated as EG) and 0.7 part of diethylene glycol were prepared by adding 0.1 part of cobalt acetate tetrahydrate. Using 0.1 part (0.04 mmol) and 0.03 part (0.12 mmol) of manganese acetate tetrahydrate as a transesterification catalyst, a transesterification reaction was carried out according to a conventional method, and 1.2 parts of an EG 1% solution of antimony trioxide (0 part .041mm
ol) and 0.016 parts (0.16 parts) of orthophosphoric acid
(4 mmol) was added to terminate the transesterification reaction. Next, a polycondensation reaction was continuously performed under high temperature and high vacuum as usual, and then a strand type chip was obtained. The intrinsic viscosity of the obtained polymer is 0.48, Col-L / b = 80 /
-2.0, diethylene glycol content is 2.0wt
% And the polymerization time was 90 minutes. No colored layer was observed by microscopic observation.

The obtained chip was exposed to sunlight for 5 hours. At this time, the amount of received ultraviolet light at 250 nm was 2500 mJ / c.
m ² . When the chip after the treatment was observed with a microscope, the thickness of the colored layer was 10 μm, and Col-L / b = 81 /
-1.5.

Further, this prepolymer was crystallized and solid-phase polymerized by a conventional method. The intrinsic viscosity of the obtained polymer is 0.70, the crystallinity is 37%, Col-L / b = 81.
/-0.5, the amount of acetaldehyde was 3 ppm.

The obtained chip was exposed to sunlight for 3 days. At this time, the amount of ultraviolet light received at 250 nm was 12000 mJ / c.
m ² . When the chip after the treatment was observed with a microscope, the thickness of the colored layer was 18 μm, and Col-L / b = 81 /
0.

Next, a preform was formed from the chip at a cylinder temperature of 300 ° C. using an injection molding machine. The preform hue was Col-L / b = 78 / 1.3. From this preform, a bottle was formed by a blow molding machine. The haze of the bottle was 1%, no unmelted material.

Comparative Example 1 The polymer obtained in Example 1 (intrinsic viscosity: 0.5, Col-L / b = 83 / -3,
The diethylene glycol content was 0.7 wt%, and no colored layer was observed by microscopic observation. ) Was used to perform an ultraviolet irradiation test.

The obtained chip was exposed to sunlight for 16 hours,
At this time, the amount of ultraviolet light received at 250 nm is 8,000 mJ / c.
m ² . When the chip after the treatment was observed with a microscope, the thickness of the colored layer was 50 μm, and Col-L / b = 83 /
0.

Further, this prepolymer was crystallized by a conventional method. Crystallinity 15%, Col-L / b = 84 /
1.0, the amount of acetaldehyde was 20 ppm.

The obtained chip was exposed to sunlight for 3 days. At this time, the amount of ultraviolet light received at 250 nm was 12,000 mJ / c.
m ² . When the chip after the treatment was observed under a microscope, the thickness of the colored layer was 70 μm, and Col-L / b = 84 /
3.0.

Next, a preform was formed from the chip at a cylinder temperature of 300 ° C. using an injection molding machine. The hue of the preform was Col-L / b = 77 / 5.3.

From this preform, a bottle was molded by a blow molding machine. The haze of the bottle was 4%, with no unmelted material.

Comparative Example 2 Intrinsic viscosity: 0.4, Col-
An amorphous polymer having an L / b of 83 / -3 and a diethylene glycol content of 3.2% by weight was obtained, and no colored layer was observed under a microscope.

The obtained chip was exposed to sunlight for 29 hours,
At this time, the amount of received ultraviolet light at 250 nm is 12000 mJ /
cm ² . When the chip after the treatment was observed with a microscope, the thickness of the colored layer was 100 μm, and Col-L / b = 8.
3/0.

Further, this prepolymer was crystallized by a conventional method, and solid phase polymerization was carried out. Crystallinity 52%, Col
-L / b = 85 / 1.0.

The obtained chip was exposed to sunlight for 3 days. At this time, the amount of received ultraviolet light at 250 nm was 12,000 mJ / c.
m ² . When the chip after the treatment was observed with a microscope, the thickness of the colored layer was 140 μm, and Col-L / b = 85 /
3.4.

Next, a preform was molded from the chip at a cylinder temperature of 300 ° C. using an injection molding machine. The hue of the preform was Col-L / b = 77 / 6.1.

A bottle was formed from this preform by a blow molding machine. The haze of the bottle was 3%, and the amount of unmelted material was large.

[0048]

According to the present invention, it is possible to provide resin granules and molded products having excellent hue and excellent resistance to discoloration upon receiving light. The resin granules of the present invention are particularly preferably used as beverage bottles.

Claims (9)

[Claims] Claims: 1. A polyethylene naphthalate resin granule containing naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component, wherein the resin granule does not have a surface layer as defined in the present invention, Alternatively, the surface layer having a thickness of not more than 20 μm, even if it has, is a polyethylene naphthalate resin granule excellent in hue. 2. An amorphous polyethylene naphthalate resin having an ultraviolet ray receiving amount of
2. The polyethylene naphthalate resin granule according to claim 1, which is produced by crystallizing before reaching 0 mJ / cm ² . 3. The polyethylene naphthalate resin granule according to claim 2, which is produced by solid phase polymerization after crystallization. 4. The method according to claim 2, wherein the amount of acetaldehyde contained in the resin particles is 10 ppm or less, and the diethylene glycol unit in the polyethylene naphthalate resin constituting the resin particles is 0.8 wt% or more and 3.0 wt% or less.
Or a particulate polyethylene naphthalate resin according to item 3. 5. The degree of crystallinity in the form of resin granules is 20%.
4. The particulate polyethylene naphthalate resin according to claim 2, which is at least 50%. 6. The polyethylene naphthalate resin granule according to claim 4, which contains a germanium compound and / or an antimony compound as a compound derived from the polymerization catalyst. 7. The polyethylene naphthalate resin granule according to claim 1, wherein the surface layer is a colored layer. 8. A molded article molded from the particulate polyethylene naphthalate resin according to claim 1. 9. A bottle formed from the polyethylene naphthalate resin granules according to claim 1.