JP2000143824A - Blow molding made from copolymer polyethylene naphthalate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a blow molding made from an easily moldable copolymer polyethylene naphthalate and having improved heat resistance, gas barrier properties, impact resistance, and light resistance by using a copolymer polyethylene naphthalate prepared by copolymerizing a polyethylene naphthalate with 2,6-decalindicarboxylic acid. SOLUTION: Naphthalenedicarboxylic acid and/or its lower alkyl ester and 1-10 mol% 2,6-decalindicarboxylic acid of the formula and/or its lower alkyl ester are polycondensed with ethylene glycol under heating to obtain a copolyethylenenaphthalate having an intrinsic viscosity of 0.60 or above, desirably, 0.65 or above. A preform obtained by injection-molding the copolymer polyethylene naphthalate is placed in a specified mold and oriented and blow- molded at a temperature higher than the secondary transition point of the polymer by 10-70 deg.C to obtain a blow molding having a failure rate of 10% or below (in a drop impact test), a color change of 8 or below in terms of a b value (in a light resistance test), an acetaldehyde content of 30 ppm or below, a haze of 5% (in a test on the body), and a body thickness of 200-500 μm. In the formula, R is H or a lower alkyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow molded article made of copolymerized polyethylene naphthalate, and more particularly to a hollow molded article made of copolymerized polyethylene naphthalate having excellent heat resistance, gas barrier properties, impact resistance and light resistance. About.

[0002]

2. Description of the Related Art Polyethylene terephthalate is widely used as a container for beverages because of its excellent properties, but is not sufficient in terms of heat resistance and gas barrier properties.

[0003] In recent years, polyethylene naphthalate has attracted attention as a material for hollow molded articles because of its excellent properties such as heat resistance, gas barrier properties, and ultraviolet absorption, and many proposals have been made by blending with polyethylene terephthalate or using it alone. ing. However, polyethylene naphthalate is not necessarily sufficient in terms of high cost and light resistance due to impact resistance and ultraviolet absorption. For example, when polyethylene naphthalate is used alone as a homopolymer, problems specific to polyethylene naphthalate may include delamination and damage due to falling of the container due to low impact resistance. Polyethylene naphthalate has the advantage of preventing its contents from being deteriorated by ultraviolet rays due to its excellent ultraviolet absorption, but also causes undesirable problems such as deterioration of hue and strength due to deterioration of the polymer itself at the same time. .

[0004] In order to solve these problems, modification by various copolymerizations, addition of an ultraviolet absorber, and the like have been studied. However, since the properties inherent in polyethylene naphthalate are deteriorated and the hue is deteriorated, It was not always enough.

[0005]

The inventor of the present invention has made intensive studies to solve these problems, and as a result, a specific ratio of 2,6-
The present inventors have found that a hollow molded article made of a polyethylene naphthalate copolymer obtained by copolymerizing a decalin dicarboxylic acid component has excellent properties and can solve the above problems, and have reached the present invention.

An object of the present invention is to provide heat resistance, gas barrier properties,
An object of the present invention is to provide a copolymerized polyethylene naphthalate hollow molded article excellent in impact resistance, light resistance, and moldability. Another object of the present invention is to provide a copolymerized polyethylene naphthalate hollow molded article having excellent heat resistance, gas barrier properties, impact resistance, light resistance, moldability, and low aldehyde content.

[0007]

According to the present invention, a 2,6-decalin dicarboxylic acid component is contained in an amount of 1 to 1 per total dicarboxylic acid component.
It is a hollow molded article made of a copolymerized polyethylene naphthalate having an intrinsic viscosity of 0.60 or more copolymerized with 0 mol%. As a preferred embodiment, the change rate of the color b value (Δ) in the light resistance test defined below is 10% or less in the drop impact test defined below.
b) is 8 or less, and the acetaldehyde content is 30 p
pm or less, and / or the haze of the hollow molded body body is 5% or less.

The naphthalenedicarboxylic acid component constituting the main acid component of the copolymerized polyethylene naphthalate in the present invention includes 2,6-naphthalenedicarboxylic acid,
Examples include 2,7-naphthalenedicarboxylic acid and 1,5-naphthalenedicarboxylic acid. Among them, 2,6-
Naphthalenedicarboxylic acid is preferred.

The naphthalenedicarboxylic acid component is obtained by using naphthalenedicarboxylic acid and / or an ester-forming derivative thereof, particularly a lower alkyl ester, in the production reaction of the copolymerized polyester. Preferred examples of the lower alkyl ester include dimethyl ester, diethyl ester, and dipropyl ester. Among them, dimethyl ester is preferably used.

In the copolymerized polyethylene naphthalate of the present invention, 2,6-decalin dicarboxylic acid component is copolymerized as a copolymer component in an amount of 1 to 10 mol%, preferably 2 to 8 mol%, based on all dicarboxylic acid components. It is necessary to be. The decalin dicarboxylic acid component is copolymerized by using a compound represented by the following formula (1) in the production reaction of the copolymerized polyester.

[0011]

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(In the formula, R is hydrogen or a lower alkyl group.) In the above formula (1), R is hydrogen or a lower alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group.

When the copolymerization amount of the 2,6-decalin dicarboxylic acid component is less than 1 mol% based on the total dicarboxylic acid components, the impact resistance of the hollow molded article is not sufficiently improved, and conversely, 10 mol% If it exceeds, when the copolymerized polyethylene naphthalate is treated in the drying step and the solid-state polymerization step due to the decrease in the crystallinity of the polymer, the handleability is deteriorated, and the moldability when molding into a hollow molded article is further reduced. It is not preferable because it is inferior and uneven thickness occurs.

The compound represented by the formula (1) includes 2,
Preferred examples include 6-decalin dicarboxylic acid and 2,6-decalin dicarboxylic acid dimethyl ester.

The copolymerized polyethylene naphthalate of the present invention may contain other dicarboxylic acid components in an amount not to impair the effects of the present invention, for example, 10 mol% or less, preferably 5 mol% or less of the total amount of all dicarboxylic acid components. May be copolymerized.

Other dicarboxylic acid components include, for example, terephthalic acid, isophthalic acid, phthalic acid, diphenyldicarboxylic acid, benzophenonedicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenyletherdicarboxylic acid, phenylindanedicarboxylic acid and the like. Aromatic dicarboxylic acids, oxalic acid, adipic acid, sebacic acid, malonic acid, succinic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, glycolic acid, oxyacids such as p-oxybenzoic acid, and teleralin dicarboxylic acid. can give. These may be used alone or in combination of two or more.

In the present invention, the glycol component of the copolymerized polyethylene naphthalate is mainly composed of ethylene glycol, but the proportion is preferably at least 90 mol%, more preferably at least 95 mol%.

In the copolymerized polyethylene naphthalate of the present invention, other glycol components are copolymerized within a range that does not impair the effects of the present invention, for example, less than 10 mol%, preferably less than 5 mol% of the total glycol components. You may. Other glycol components include, for example, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol, cyclohexanediol, and cyclohexanedimethanol. Glycol, o, m, p-xylylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, 4,4′-bis (2-hydroxyethoxy) biphenyl, 2,2-bis [4- (2- [Hydroxyethoxy) phenyl] propane, 1,3-bis (2-hydroxyethoxy) benzene, 1,2-bis (2-hydroxyethoxy) benzene, 4,4′-bis (hydroxyethoxy) diphenylsulfo And diphenols such as aromatic glycols such as bisphenol A, hydroquinone, catechol, dihydroxynaphthalene, dihydroxybiphenyl and dihydroxydiphenylsulfone. These may be used alone or in combination of two or more.

Although the copolymerized polyethylene naphthalate of the present invention is substantially linear, it is 2 mol% or less, preferably 1 mol%, based on the total acid components within a range not to impair the effects of the present invention.
A polycarboxylic acid or polyhydroxy compound having three or more functional groups may be copolymerized within the range of mol% or less. Specific examples of the polycarboxylic acid and polyhydroxy compound include trimellitic acid and pentaerythritol.

In the present invention, the copolymerized polyethylene naphthalate has a total amount of 15 mol% of a copolymerized acid component including 2,6-decalin dicarboxylic acid and a copolymerized glycol component.
Is preferably not exceeded.

In the present invention, it is preferred that the hollow molded article made of the copolymerized polyethylene naphthalate, such as a container or a bottle, has a breakage rate of 10% or less in a drop impact test defined below.

In the drop impact test, after copolymerized polyethylene naphthalate was injection-molded and oriented blow-molded to form a hollow molded body having an internal volume of 1.55 liter, a carbon dioxide having a gas generating capacity of 4 times the volume at room temperature was obtained. Fill with water, 1m
It is carried out by dropping from a height of 30 m onto concrete with a slope of 30 degrees. The breakage rate at that time is determined by counting the number of carbonated water contents leaking due to breakage of the bottom of the hollow molded body. Note that the number of n in the test is 30.

If the breakage rate exceeds 10%, the impact resistance of the hollow molded article cannot be sufficiently improved, which is not preferable.

The hollow molded article made of the copolymerized polyethylene naphthalate according to the present invention has, as light resistance properties, a change in color b value (Δb) in a light resistance test defined below.
Is preferably 8 or less.

Change in color b value in light fastness test (Δ
In b), the preform of the hollow molded article or the mouth of the hollow molded article was pulverized and subjected to crystallization treatment at 170 ° C. for 3 hours, and then the color b1 value was measured using Z- # 80 manufactured by Nippon Denshoku Industries Co., Ltd. Further, the preform of the same hollow molded body or the mouth of the hollow molded body was exposed to ultraviolet light for 20 hours with a sunshine weather meter S80 manufactured by Suga Test Instruments Co., Ltd., and the irradiated part was pulverized. After the conversion treatment, the color b2 value was measured in the same manner, and the change in the color b value (Δb) [= b2−
b1] is obtained and evaluated for light resistance.

Change in color b value in light fastness test (Δ
When b) exceeds 8, the copolymerized polyethylene naphthalate hollow molded article is not preferable because it is greatly colored by light, impairing the appearance and reducing the commercial value, as well as lowering the mechanical strength.

The copolymerized polyethylene naphthalate in the present invention can be produced according to a method known as a method for producing polyester. For example, naphthalene dicarboxylic acid and / or a lower alkyl ester thereof and 2,6-decalin dicarboxylic acid represented by the formula (1) and / or
Alternatively, it can be produced by a polycondensation reaction between the lower alkyl ester and ethylene glycol under heating. The production method differs depending on whether a dicarboxylic acid or a lower alkyl ester of a dicarboxylic acid is used. When a lower alkyl ester is used, it is a method called a transesterification method, and it can be obtained by subjecting a monomer obtained by a transesterification reaction to a polycondensation reaction under a high temperature and a high vacuum. On the other hand, when using a dicarboxylic acid is a method called direct esterification method,
After the esterification reaction, it can be obtained by performing a polycondensation reaction under high temperature and high vacuum. The catalyst used in either the transesterification method or the direct esterification method is not particularly limited. When produced by the transesterification method, a transesterification catalyst is required in addition to the polycondensation catalyst. As the catalyst, a manganese compound, a calcium compound, a magnesium compound, a titanium compound generally known widely as a polyester catalyst are used. Examples include metal compounds such as compounds, zinc compounds, sodium compounds, potassium compounds, cerium compounds, and lithium compounds, and a cobalt compound that also acts as a color adjuster may be optionally added. Regardless of the production method, germanium compounds and antimony compounds are preferably used as the polycondensation catalyst.

In either case of the transesterification method and / or the direct esterification method, it is preferable to add a phosphorus compound as a stabilizer. As the phosphorus compound, orthophosphoric acid, phosphorous acid, phosphate ester and the like are used. .

The copolymer polyethylene naphthalate hollow molded article of the present invention has an acetaldehyde content of 30 pp.
m or less. When the acetaldehyde content exceeds 30 ppm, when the beverage is filled into the copolymerized polyethylene naphthalate hollow molded article, the flavor property is inferior.

The acetaldehyde content is 30 ppm
This can be achieved by melt-polycondensing the raw material polymer, copolymerized polyethylene naphthalate, before molding the hollow molded article, and then performing solid phase polymerization to sufficiently reduce the amount of acetaldehyde contained. In addition, the copolymerized polyethylene naphthalate obtained by solid-phase polymerization has a lower melting point and lower melt viscosity than polyethylene naphthalate homopolymer, and can suppress the molding temperature or shear heat when molding a hollow molded body. This has the advantage that the amount of acetaldehyde by-produced by decomposition can be suppressed.

The solid-phase polymerization of the copolymerized polyethylene naphthalate is preferably carried out at 170 ° C. or higher. When the solid phase polymerization is performed at a temperature lower than 170 ° C., the content of acetaldehyde is not sufficiently reduced, and as a result, it is difficult to suppress the acetaldehyde content to 30 ppm or less when molded into a hollow molded article, which is not preferable.

Thus, the solid phase polymerization temperature is preferably 170 ° C. or higher, but the upper limit is preferably 220 ° C. or lower. When the solid phase polymerization is carried out at a temperature exceeding 220 ° C., the content of acetaldehyde can be sufficiently reduced, and the copolymerized polyester obtained by melt polycondensation can be efficiently polymerized. This is not preferable because a problem of fusion resulting from a decrease in crystallinity occurs.

The copolymer polyethylene naphthalate hollow molded article of the present invention has an intrinsic viscosity of 0.60 or more, preferably 0.65 or more. When the intrinsic viscosity is less than 0.60, not only is the strength of the obtained copolymerized polyethylene naphthalate hollow molded article reduced, but also the moldability is inferior at the time of blow molding.

In the present invention, the copolymer polyethylene naphthalate hollow molded article preferably has a body haze of 5% or less. When the body haze is higher than 5%, the transparency of the hollow molded article is low, which is not preferable in terms of commercial value. The thickness of the body of the hollow molded body varies depending on its capacity and use, but is usually from 200 μm to 500 μm.

The hollow molded article made of the copolymerized polyethylene naphthalate according to the present invention may contain various additives such as an antioxidant, an ultraviolet absorber, an antistatic agent, a dye and a pigment, if necessary. .

The hollow molded article of the present invention includes a container,
Bottles are preferred, but these can be manufactured according to conventionally known manufacturing methods. For example, a transparent preform is formed by injection-molding a copolymerized polyethylene naphthalate, and then the preform is placed in a predetermined mold, at a temperature higher by 10 to 70 ° C. than the secondary transition point of the polymer, and further by 20 to Bottles can be manufactured by orientation blow molding at a temperature 50 ° C. higher.

[0037]

The present invention will be described in more detail with reference to the following examples. The present invention is not limited by the embodiment. Various characteristics were measured as follows.

(1) Intrinsic viscosity Calculated from the solution viscosity measured at 35 ° C. using a phenol / tetrachloroethane = 6/4 (weight ratio) mixed solvent.

(2) Drop impact test After filling the hollow molded body with carbonated water having a gas generating capacity of 4 times the volume, the hollow molded body was dropped from a height of 1 m onto concrete having an inclination of 30 degrees, and the contents leaked. From the number of pieces. The number n is 30.

(3) Light Resistance Test After drying the polymer at 160 ° C. for 5 hours, 55 g of a preform was prepared at a molding temperature of 305 ° C. using an injection molding machine 100DM manufactured by Meiki Seisakusho Co., Ltd. After crushing the preform as a precursor, crystallization treatment was performed at 170 ° C. for 3 hours, and the color b1 value was measured using Z- # 80 manufactured by Nippon Denshoku Industries Co., Ltd. The preform was exposed to ultraviolet light for 20 hours using a sunshine weather meter S80 manufactured by Suga Test Instruments Co., Ltd., and the irradiated portion was pulverized. After crystallization treatment at 170 ° C. for 3 hours, the color b2 value was measured in the same manner. The change in the color b value before and after the sunshine weather meter treatment (Δb) [= b2−b1] was evaluated as the light fastness.

(4) Haze After drying the polymer at 160 ° C. for 5 hours, a preform of 55 g was molded at a molding temperature of 305 ° C. using an injection molding machine 100DM manufactured by Meiki Seisakusho, and blow-stretched.
A hollow molded body having an inner volume of 1.55 liter and a body thickness of 300 μm was obtained. The body of the hollow molded body was cut out and measured with a turbidity meter manufactured by Nippon Denshoku Industries Co., Ltd.

(5) Acetaldehyde content The polymer was freeze-pulverized and measured by HS-GC manufactured by Hitachi, Ltd.

Example 1 99.0 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester, 1.0 part by weight of 2,6-decalin dicarboxylic acid dimethyl ester and 50.7 parts by weight of ethylene glycol were mixed with manganese acetate tetrahydrate. In the presence of 0.030 parts by weight (30 mmol%) of the hydrate and 0.010 parts by weight (10 mmol%) of cobalt acetate tetrahydrate, a transesterification reaction was carried out by a conventional method. 0.018 parts by weight of antimony (15
Mmol), and 0.020 parts by weight (50 mmol%) of orthophosphoric acid was added before the end of the transesterification reaction.
Next, a polycondensation reaction was performed at 295 ° C. under a high vacuum of 1 mmHg or less to obtain a copolymerized polyethylene naphthalate having an intrinsic viscosity of 0.52. The obtained polymer was further heated at 215 ° C, 1
Solid phase polymerization was performed for 5 hours to obtain a polymer having an intrinsic viscosity of 0.68.

After the obtained copolymerized polyethylene naphthalate was dried at 160 ° C. for 5 hours, a preform of 55 g was molded at a molding temperature of 305 ° C. using an injection molding machine 100DM manufactured by Meiki Seisakusho, and this was blown. It was stretched to form a hollow molded body having an inner volume of 1.55 liter and a body thickness of 300 μm. The physical properties of the obtained copolymerized polyethylene naphthalate hollow molded article, such as the intrinsic viscosity, the change in color b value (Δb) in the light resistance test, the breakage rate in the drop impact test, and the acetaldehyde content, are as shown in Table 1. there were.

Example 2 94.3 parts by weight of 2,6-naphthalenedicarboxylic acid, 5.7 parts by weight of 2,6-decalin dicarboxylic acid and 57.3 parts by weight of ethylene glycol were slurried at room temperature and placed in an autoclave equipped with a stirrer. The esterification reaction was carried out under a pressure of 3 kg / cm ^{2 in} the presence of 0.011 part by weight (10 mmol%) of cobalt acetate tetrahydrate, and when the amount of distilled water reached 15.0 parts by weight, The pressure was released, and the reaction was carried out at normal pressure.
The reaction was terminated by adding 4 parts by weight (30 mmol%). Subsequently, 0.020 parts by weight of antimony trioxide (15
(Mol%), and a polycondensation reaction was performed at 295 ° C. under a high vacuum of 1 mmHg or less to obtain a copolymerized polyethylene naphthalate having an intrinsic viscosity of 0.58.

The obtained polymer was further subjected to solid-state polymerization at 205 ° C. to obtain a polymer having an intrinsic viscosity of 0.71. The obtained copolymerized polyethylene naphthalate was molded in the same manner as in Example 1 to obtain a hollow molded body. Table 1 shows the physical properties of the obtained hollow molded article.

Comparative Example 1 85.5 parts by weight of 2,6-naphthalenedicarboxylic acid dimethyl ester, 14.5 parts by weight of 2,6-decalin dicarboxylic acid dimethyl ester and 50.5 parts by weight of ethylene glycol were mixed with manganese acetate tetrahydrate. In the presence of 0.030 parts by weight (30 mmol%) of the hydrate and 0.010 parts by weight (10 mmol%) of cobalt acetate tetrahydrate, a transesterification reaction was carried out by a conventional method. 0.018 parts by weight of antimony (15
Mmol), and 0.020 parts by weight (50 mmol%) of orthophosphoric acid was added before the end of the transesterification reaction.
Next, a polycondensation reaction was performed at 295 ° C. under a high vacuum of 1 mmHg or less to obtain a copolymerized polyethylene naphthalate having an intrinsic viscosity of 0.60.

The obtained polymer was further subjected to solid-state polymerization at 195 ° C. to obtain a polymer having an intrinsic viscosity of 0.78. The obtained copolymerized polyethylene naphthalate was molded in the same manner as in Example 1 to obtain a hollow molded body. The physical properties of the obtained copolymerized polyethylene naphthalate hollow molded article are as shown in Table 1. Due to uneven stretching of the hollow molded article due to uneven thickness, the breakage rate in a drop impact test is high and the improvement effect is low.

[Examples 3 and 4] The same as Example 1 except that the proportions of 2,6-naphthalenedicarboxylic acid dimethyl ester and 2,6-decalin dicarboxylic acid dimethyl ester were changed as shown in Table 1. The solid-phase polymerization temperature in Example 4 was 205 ° C.) to obtain a copolymerized polyethylene naphthalate hollow molded article. Table 1 shows the physical properties of the obtained hollow molded article.
As described.

Comparative Examples 2 and 3 The same as in Example 1 except that the proportions of 2,6-naphthalenedicarboxylic acid dimethyl ester and decalin dicarboxylic acid dimethyl ester were as shown in Table 1, except that the solid content of Comparative Example 3 was Layer polymerization temperature is 205
C) to obtain a copolymerized polyethylene naphthalate hollow molded article. Table 1 shows the physical properties of the obtained hollow molded article.

[0051]

[Table 1]

[0052]

The hollow molded article comprising the copolymerized polyethylene naphthalate of the present invention is excellent in heat resistance, gas barrier resistance, impact resistance, light resistance, moldability, etc., and has a high commercial value in food packaging applications. Can be widely used as bottles.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ryoji Tsukamoto 77 Kitayoshida-cho, Matsuyama-shi, Ehime Prefecture Teijin Limited Matsuyama Office F-term (reference) 4F071 AA45 AA88 AF07 AF23 AF45 AF57 AH05 BB13 BC04 4J029 AA03 AB07 AC02 AD01 AD10 AE01 BA03 CC05A CC06A CD07 HA01 HB01 HB03A

Claims (6)

[Claims] 1. A hollow molded article comprising a copolymerized polyethylene naphthalate having an intrinsic viscosity of 0.60 or more obtained by copolymerizing a 2,6-decalin dicarboxylic acid component in an amount of 1 to 10 mol% based on all dicarboxylic acid components. 2. The hollow molded article according to claim 1, wherein a breakage rate in a drop impact test defined in this specification is 10% or less. 3. The hollow molded article according to claim 1, wherein a change (Δb) in a color b value in a light resistance test defined in the present specification is 8 or less. 4. The hollow molded article according to claim 1, wherein the acetaldehyde content is 30 ppm or less. 5. The hollow molded article according to claim 4, which is obtained by molding a copolymerized polyethylene naphthalate solid-phase polymerized at a temperature of 170 ° C. or higher. 6. The hollow molded body according to claim 1, wherein the haze of the body of the hollow molded body is 5% or less.