JPH06122145A - Synthetic resin container - Google Patents

Abstract

(57) [Summary] [Structure] A synthetic resin container comprising a neck portion, a body portion and a bottom portion obtained by biaxial stretch blow molding of a parison obtained by multi-layer molding of two or more kinds of synthetic resins. The body has three or more layers in which the inner layer and the outer layer are made of polycarbonate resin and the middle layer is made of polyethylene terephthalate resin (preferably, polycarbonate / polyethylene terephthalate = 99.8 / 0.2 to 50/50 (weight ratio)). A synthetic resin container having a multi-layer structure. [Effect] The synthetic resin container of the present invention has excellent gas barrier properties and good heat resistance, that is, it does not shrink or deform due to hot filling of the contents without prior heat setting treatment, and can be further stretched. Since whitening is unlikely to occur, it has good transparency and an excellent appearance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biaxially stretch blow molded synthetic resin container, and more particularly to a transparent biaxially stretched blow container having excellent gas barrier properties and heat resistance.

[0002]

2. Description of the Related Art A synthetic resin container obtained by blow molding a polycarbonate resin has heat resistance practically sufficient for filling contents such as foods, and is often subjected to hot water sterilization. Used in bottles, etc. However, containers made of polycarbonate resin generally have poor gas barrier properties,
It is not used for filling contents such as fruit juice drinks that require gas barrier properties.

On the other hand, a synthetic resin container made of a polyester resin such as polyethylene terephthalate resin and obtained by biaxially stretch-blowing a parison has a body of the container biaxially oriented in a molecular orientation in a gas barrier property and transparency. , It has come to be widely used as a lightweight synthetic resin container. However, in a synthetic resin container obtained by biaxially stretch blow molding this polyethylene terephthalate resin,
When the contents are hot-filled in order to store the contents in a sterilized state, there is a problem that the container contracts or the container is deformed.

In order to solve such a problem, generally, a so-called heat setting treatment is carried out in which heat treatment is carried out in a state in which the body of the container in which the molecular orientation in the biaxial direction is generated is molecularly oriented. As a method for imparting heat resistance to a synthetic resin container without performing a complicated heat setting treatment, multi-layer molding using a polyethylene terephthalate resin and a heat resistant resin has been studied.

[0005]

Among the multi-layer moldings,
In the multilayer molding using the polycarbonate resin as the heat resistant resin, the polycarbonate resin has been used as the intermediate layer in the related art, so that it has been difficult during blow molding. That is, since the biaxial stretch blow molding is performed at a temperature lower than the temperature suitable for stretching the polycarbonate resin and suitable for stretching the polyethylene terephthalate resin, the polycarbonate resin in the intermediate layer is in a cold stretched state, resulting in significant whitening. Therefore, there is a problem that the transparency is impaired and the aesthetics of the container is impaired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a transparent synthetic resin container having gas barrier properties and heat resistance without performing complicated processing such as heat setting. That is, the gist of the present invention is (1) a synthetic resin container comprising a neck portion, a body portion and a bottom portion obtained by biaxial stretch blow molding of a parison obtained by multilayer molding of two or more kinds of synthetic resins, The present invention resides in a synthetic resin container characterized in that the body has a multilayer structure of three or more layers in which the inner layer and the outer layer are made of polycarbonate resin and the intermediate layer is made of polyethylene terephthalate resin.

The present invention will be described in detail below. The polycarbonate resin used as the synthetic resin container of the present invention is, for example, one or more dihydric phenols represented by the following general formula [I] or [II].

[0008]

[Chemical 1]

(However, R ¹ and R ² each independently represent an alkyl group having 1 to 6 carbon atoms or a phenyl group, and R ³ is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms. Show.)

[0010]

[Chemical 2]

[Wherein R ⁴ and R ⁵ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group or a phenyl group, X is a single bond,

[0012]

[Chemical 3]

(However, R ⁶ and R ⁷ are hydrogen and have 1 to 1 carbon atoms.
6 represents an alkyl group or a phenyl group of 6), or

[0014]

[Chemical 4]

(Where n is an integer of 4 to 8)] and a carbonic acid ester-forming compound. Specific examples of the dihydric phenol represented by the general formula [I] include, for example, 1-phenyl-
1,1-bis (2-isopropyl-5-methyl-4-hydroxyphenyl) methane, 1-phenyl-1,1-bis (2-methyl-5-isopropyl-4-hydroxyphenyl) methane, 1-phenyl- 1,1-bis (2,5
-Dimethyl-4-hydroxyphenyl) methane, 1-
(2-methylphenyl) -1,1-bis (2-methyl-
5-isopropyl-4-hydroxyphenyl) methane,
1- (2-methylphenyl) -1,1-bis (2-isopropyl-5-methyl-4-hydroxyphenyl) methane, 1- (4-cyanophenyl) -1,1-bis (2,2
5-dimethyl-4-hydroxyphenyl) methane, 1-
(4-phenylphenyl) -1,1-bis (2-methyl-5-isopropyl-4-hydroxyphenyl) methane, 1-phenyl-1,1-bis (2-tert-butyl-5-methyl-4-) Hydroxyphenyl) methane,
1,1-bis (2-butyl-5-methyl-4-hydroxyphenyl) butane, 1,1-bis (2-tert-butyl-5-methyl-4-hydroxyphenyl) propane, 1,1-bis ( 2-tert-butyl-5-methyl-4-hydroxyphenyl) butane, 1,1-bis (2
Examples include -tert-butyl-5-methyl-4-hydroxyphenyl) isobutane, 1,1-bis (2-tert-butyl-5-methyl-4-hydroxyphenyl) heptane, and the like.

Specific examples of the dihydric phenol represented by the above general formula [II] include, for example, 2,2-bis (3
-Methyl-4-hydroxyphenyl) propane, 1,1
-Bis (3-phenyl-4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) methane,
2,2-bis (4-hydroxyphenyl) propane,
3,3-bis (4-hydroxyphenyl) heptane, bis (3-methyl-4-hydroxyphenyl) methane,
2,2-bis (3-methyl-4-hydroxyphenyl)
Butane, 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane, 2- (3-methyl-4-hydroxyphenyl) -2- (4-hydroxyphenyl) -2-phenylethane, bis (3- Methyl-4-hydroxyphenyl) diphenylmethane, 4,4′-dihydroxybiphenyl, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl)
Cyclohexane, 1,1-bis (3-methyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (3-
Examples thereof include cyclohexyl-4-hydroxyphenyl) cyclohexane.

The most preferred of these is 2,2
-Bis (4-hydroxyphenyl) propane (bisphenol A). On the other hand, examples of the carbonic acid ester forming compound include phosgene, diphenyl carbonate,
Examples thereof include bisaryl carbonates such as di-p-tolylcarbonate, phenyl-p-tolylcarbonate, di-p-chlorophenylcarbonate, dinaphthylcarbonate, and dialkylcarbonates such as dimethylcarbonate. The average molecular weight of the obtained polycarbonate is not particularly limited, but is preferably 14,000 to 30,000.

On the other hand, the polyethylene terephthalate resin used in the synthetic resin container of the present invention contains a homopolymer of polyethylene terephthalate as a main component. Aromatic dicarboxylic acids such as diphenoxyethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, aliphatic compounds such as adipic acid, sebacic acid and azelaic acid It may be substituted with a dicarboxylic acid, a bifunctional carboxylic acid such as an oxy acid such as P-β-hydroxyethoxybenzoic acid, or the like. In addition, a part of the ethylene glycol component is, for example, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentyl glycol, diethylene glycol, 1,1-cyclohexane dimethylol, 1,4-cyclohexane dimethylol, 2 , 2-bis (4'-β-hydroxyethoxyphenyl) propane, bis (4'-β-hydroxyethoxyphenyl) sulfonic acid, and other glycols and their functional derivatives substituted with polyfunctional compounds. May be. The substitution ratios of these bifunctional carboxylic acid component and glycol component are usually 15 mol% or less, preferably 5 mol% or less.

The intrinsic viscosity of the polyester resin is usually selected from the range of 0.4 to 2.0, preferably 0.5 to 1.2 from the viewpoint of moldability. In the present invention, first, a parison is obtained by multilayer molding of two or more kinds of synthetic resins. Here, as the two or more kinds of synthetic resins, in addition to the above-mentioned polycarbonate resin and polyethylene terephthalate resin, an adhesive layer is formed. As the resin, polyolefin, ethylene-vinyl acetate copolymer, olefin polymer such as polyvinyl alcohol, and as the resin forming the gas barrier layer, nylon-6, nylon-
Polyamide resin such as 66 may be used.

For the multi-layer molding of the parison, methods well known to those skilled in the art such as coextrusion molding and injection molding are adopted. The synthetic resin container of the present invention is obtained by biaxially stretching the parison thus obtained by a method well known in the art, and comprises a neck portion, a body portion and a bottom portion, of which at least the body portion is multilayered. Must be a structure. Only the body part may have a multi-layer structure, but the neck part and the bottom part may also have a multi-layer structure.

Here, the multi-layer structure is a structure of three or more layers in which the innermost layer and the outermost layer are made of the above-mentioned polycarbonate resin, and at least one of the intermediate layers is made of the above-mentioned polyethylene terephthalate resin. As another intermediate layer, for example, a five-layer structure, a seven-layer structure, or the like can be formed by including an adhesive layer made of the above-mentioned polyolefin resin or the like and a gas barrier layer made of polyamide or the like.

However, the weight ratio of at least the polycarbonate resin and the polyethylene terephthalate resin forming the body is polycarbonate resin / polyethylene terephthalate resin = 99.8 / 0.2 to 50/50, preferably 99.5 / 0.5. It is preferably ˜80 / 20 (weight ratio). When the weight ratio of the polyethylene terephthalate resin in the body of the synthetic resin container is 0.2% or less, the gas barrier property is not significantly improved as compared with the case of the polycarbonate resin container. On the other hand, when the weight ratio of the polyethylene terephthalate resin is 50% or more, whitening due to crystallization of the polyethylene terephthalate resin forming the intermediate layer is remarkable and the transparency of the container is impaired.

The thickness of the multi-layer structure of the synthetic resin container of the present invention is not particularly limited as long as the weight ratio of the polycarbonate resin and the polyethylene terephthalate resin satisfies the above-mentioned conditions, and can be arbitrarily selected. .

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples without departing from the gist thereof. Various physical properties in this example were measured by the following methods. Polycarbonate / polyethylene terephthalate weight ratio Polycarbonate / polyethylene terephthalate weight ratio is Shimadzu's specific gravity measuring device SMG-210U-
01, the synthetic resin container obtained in the example (multilayer molded product)
The density was measured using a calibration curve obtained from the respective densities of the polycarbonate and polyethylene terephthalate, which were measured in advance. Oxygen transmission rate MODERN CONTROLS, INC, OX-
Using TRAN 10-50A, temperature 23 ° C, humidity 10
It was measured at 0%. The oxygen permeability in this example is a value measured in an air atmosphere and converted to a value in an oxygen (O ₂ ) atmosphere. Made by Haze Suga Test Machine, SM color computer MODEL
The haze of the container body was measured using SM-5.

Example 1 Bisphenol A type polycarbonate resin having an average molecular weight of 22000 (Novarex 702, manufactured by Mitsubishi Kasei Co., Ltd.)
2A; Novarex is a registered trademark) and an intrinsic viscosity of 0.75
Using the homopolyethylene terephthalate resin of, the inner and outer layers are made of polycarbonate resin, and the middle layer is made of polyethylene terephthalate resin. After adjusting the surface temperature to about 155 to 160 ° C, biaxial stretch blow molding is performed using a blow mold at room temperature, and the height is about 225 mm and the outer diameter of the body is about 44 m.
A synthetic resin container of m was obtained. Both injection molding and blow molding are ASB-50TH manufactured by Nissei ASB Machine Co., Ltd.
Was used.

The obtained synthetic resin container had a polyethylene terephthalate resin content of 6.3 wt%, and was filled with hot water at 90 ° C., which was carried out as a heat resistance test, to the neck of the container.
No deformation of the container was observed after standing at room temperature for 30 minutes. The oxygen permeability of the container is 0.52 cc / pg · d
The haze of the body of the container was 1.4%. The haze of the container body was practically no different from the haze of the synthetic resin container body shown in Comparative Example-1.

Example-2 A polycarbonate resin having an average molecular weight of 22,000 and a homopolyethylene terephthalate resin having an intrinsic viscosity of 0.75 similar to those in Example-1 were used in the same manner as in Example-1 to obtain a height of about 225 mm and a body portion. A synthetic resin container having an outer diameter of about 44 mm was obtained. The content of polyethylene terephthalate resin in the obtained synthetic resin container was 5.2 wt%, and the container was deformed after the hot water of 90 ° C., which was used as a heat resistance test, was filled up to the neck of the container and left for 30 minutes. There wasn't. The oxygen permeability of the container was 0.79 cc / pkg · day, and the haze of the body of the container was 1.1%. The haze of the container body was practically no different from the haze of the synthetic resin container body shown in Comparative Example-1.

Example-3 Polycarbonate resin having an average molecular weight of 22000 used in Example-1 and isophthalic acid 3.3 m having an intrinsic viscosity of 0.84
Using ol% copolymerized polyethylene terephthalate resin, a synthetic resin container having a height of about 225 mm and a barrel outer diameter of about 44 mm was obtained in the same manner as in Example-1. The content of polyethylene terephthalate resin in the obtained synthetic resin container was 4.3w.
It was t%, and no deformation of the container was observed after the container was filled with 90 ° C. hot water, which was used as a heat resistance test, and left for 30 minutes. The oxygen permeability of the container is 0.56c
c / pgkg · day, haze of container body is 0.6%
Met. The haze of the container body was not different from the haze of the synthetic resin container body shown in Comparative Example-1.

Comparative Example-1 Using the polycarbonate resin having an average molecular weight of 22,000 used in Example-1, a height of about 145 mm and an outer diameter of the body of about 2
After injection molding an 8 mm parison and adjusting the surface temperature of this parison to about 155 to 160 ° C, biaxial stretch blow molding was performed using a blow mold at room temperature, and the height was about 225 mm, outside the barrel. A synthetic resin container having a diameter of about 44 mm was obtained. No deformation of the container was observed after filling the container neck with hot water at 90 ° C., which was carried out as a heat resistance test of the obtained synthetic resin container, and allowed to stand for 30 minutes. The oxygen permeability of the container was 2.09 cc / pkg · day, and the haze of the body of the container was 0.6%. The physical properties of the synthetic resin containers used in Examples and Comparative Examples are shown in Table 1.

[0030]

[Table 1]

[0031]

INDUSTRIAL APPLICABILITY The synthetic resin container of the present invention has excellent gas barrier properties and good heat resistance, that is, it does not shrink or deform due to hot filling of the contents without prior heat setting treatment, and Since whitening due to stretching hardly occurs, it has good transparency and an excellent appearance.

Claims (2)

[Claims] 1. A synthetic resin container comprising a neck, a body and a bottom obtained by biaxial stretch blow molding of a parison obtained by multi-layer molding of two or more kinds of synthetic resins, wherein at least the body is A synthetic resin container having a multilayer structure of three or more layers, wherein the inner layer and the outer layer are made of polycarbonate resin and the intermediate layer is made of polyethylene terephthalate resin. 2. The weight ratio of the polycarbonate resin and the polyethylene terephthalate resin forming the body is polycarbonate resin / polyethylene terephthalate resin = 9.
It is 9.8 / 0.2-50 / 50, The synthetic resin container of Claim 1 characterized by the above-mentioned.