JP2002347735A - PET two-layer stretch blow molded container - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Even if PET waste is reused as a molding material,
Provided is a PET two-layer stretch blow-molded container which has no risk of harm to the human body, does not have an adverse effect on the contents, such as an unpleasant odor, and has a good appearance. An outer layer shell is brought into close contact with a cavity surface of a female mold of an injection mold for a preform, and fixed in advance.
A PET biaxially stretch blow-molded container in which an inner shell is integrally molded inside an outer shell to produce a two-layer preform, and the two-layer preform is biaxially stretch blow-molded. The material is a virgin molding material, the molding material of the outer shell 100 is a recycled molding material, and the two-layer preform 10 has an average thickness of the outer shell D1 and an average thickness of the inner shell. To D2
, D1: D2 = 5.5: 0.8-
0.8: 3.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PET two-layer stretch blow-molded container in which PET waste is reused as a molding material.

[0002]

2. Description of the Related Art Conventionally, PET bottles obtained by biaxially stretch-blow-molding polyethylene terephthalate (PET) for foods such as natural water, fruit drinks, soft drinks, edible oils and sauces have been used in a wide range of food fields. This PE
The T bottle was generally a single-layer bottle obtained by biaxially stretch-blowing an injection-molded single-layer preform (test tubular preform).

[0003]

However, from the standpoint of environmental protection, the full enforcement of the Containers and Packaging Recycling Law is 2,000.
With the implementation in April 2000, companies were obliged to recycle. However, a single-layer PET bottle formed by pulverizing or pelletizing PET waste to produce a reclaimed molding material and biaxially stretch blow-molded using the reclaimed molding material is used for the human body in the reclaimed molding material. There was a possibility that foreign substances that could cause harm, and substances that give off-flavors or discomfort were mixed. For this reason, the recycled molding material could not be conventionally used for a bottle for food use. Therefore, a two-layer PET bottle using a recycled molding material for the outer shell and a virgin molding material for the inner shell is in the trial production research stage. However, whitening may occur in the shell during molding. The phenomenon has a problem that the appearance of the bottle is significantly impaired.

The present invention solves the above-mentioned conventional problems in the recycling of PET waste. Even if PET waste is reused as a molding material, there is no danger of harm to the human body. An object of the present invention is to provide a PET two-layer stretch blow-molded container which does not have an adverse effect on the contents, such as an unpleasant odor or deterioration, and has good appearance.

[0005]

That is, the first aspect of the present invention is as follows.
According to the invention, a two-layered preform is prepared by bringing an outer shell into close contact with a cavity surface of a female mold of an injection molding die for a preform, and integrally injection-molding an inner shell inside the outer shell. A biaxially stretch blow-molded PET container obtained by biaxially stretch-blow-molding the two-layer preform, wherein the molding material of the outer shell is a recycled molding material, and the molding material of the inner shell is virgin. The two-layer preform is a molding material, and the average thickness of the outer shell is D1, and the average thickness of the inner shell is D2.
Wherein PET: D2: 5.5: 0.8 to 0.8: 3.5.

Next, a second invention of the present invention is to
The outer shell is closely adhered to the cavity surface of the female mold of the injection mold for the preform, and the inner shell is integrally molded inside the outer shell to produce a two-layer preform. Biaxially stretch blow molded P
ET biaxially stretch blow molded container, wherein the molding material of the outer shell is a molding material obtained by mixing a recycled molding material and a virgin molding material, and the molding material of the inner shell is only a virgin molding material. And when the two-layer preform has an average thickness of the outer shell of D1 and an average thickness of the inner shell of D2, D1: D2 = 5.5: 0.8 to 0.8. : 3.5 It is a PET two-layer stretch blow-molded container characterized by the following.

Next, a third invention of the present invention is the PET double layer according to the first or second invention, wherein the recycled molding material is a pulverized material obtained by pulverizing PET waste. It is a stretch blow molded container.

Next, a fourth invention of the present invention is the PET bilayer according to the first or second invention, wherein the recycled molding material is a pulverized material obtained by pulverizing PET waste. It is a stretch blow molded container.

A fifth invention of the present invention is the PET double-layer stretch blow according to the third or fourth invention, wherein the recycled molding material has an intrinsic viscosity increased by solid-state polymerization. It is a molded container.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A PET two-layer stretch blow-molded container according to one embodiment of the present invention first has a through hole (1) for a gate formed at the bottom of a test tube shown in FIG.
The outer shell (100) having the above (10) is fixed to the cavity surface of the female mold of the injection mold for the preform in advance by closely contacting with the inner shell (20).
0) is integrally injection-molded with a virgin (virgin, new molding material) molding material to form a two-layer preform (1).
0), and then biaxially stretch blow molded using this two-layer preform. The gate (11) of the two-layer preform (10) is located at the inner shell (2).
00) at the bottom center.

Next, a PET double-layer stretch blow-molded container according to another embodiment of the present invention is manufactured by injection molding a molding material obtained by mixing a recycled molding material and a virgin molding material, as shown in FIG. An outer shell (100) having a through hole (110) for a gate at the bottom of a tubular shape is fixed to the cavity surface of the female mold of the injection mold for a preform in advance by tightly contacting the inner shell. (200) is integrally injection-molded with a virgin molding material to produce a two-layer preform (10), and then biaxially stretch blow-molded using this two-layer preform.

In the two-layer preform, the average thickness of the outer shell is D1 and the average thickness of the inner shell is D2.
, D1: D2 = 5.5: 0.8-
The product is designed within the range of 0.8: 3.5.
According to the knowledge obtained from the prototype test of the inventors, the maximum average thickness that does not cause whitening during injection molding of a single-layer PET preform is 5.5 mm,
When the outer shell is inserted in advance into the injection mold for preform and the inner shell is integrally formed by injection molding, the maximum average thickness of the inner shell which does not cause whitening phenomenon is 3.5 m.
m. The minimum average thickness of the PET resin that can flow in the cavity of the mold (the space between the female mold and the male mold) was 0.8 mm.

The molding material for regenerating the outer shell is a pulverized material obtained by pulverizing PET waste, or a pellet obtained by pulverizing the pulverized material of PET waste (pellet,
Small-lumped molding material). Furthermore, the intrinsic viscosity of these regenerated molding materials is increased by solid-phase polymerization (a method of polymerizing while maintaining the solid phase). In this solid-phase polymerization, the regenerated molding material is heated under a nitrogen atmosphere at a constant temperature for a certain period of time so that the intrinsic viscosity (Intrinsic viscosity) of the regenerated molding material is increased.
c Viscosity). In addition, the recycled molding material subjected to solid-state polymerization has a uniform intrinsic viscosity, stable moldability, and stable quality such as rigidity of the molded product.
Prevents whitening. At the same time, it is also possible to remove residual volatile components that cause an unpleasant odor in the recycled molding material.

Since the PET double-layer stretch blow-molded container of the present invention uses a molding material regenerated from PET waste for the outer shell and a virgin PET molding material for the inner shell, the content is reduced. Has no contact with the outer shell using the recycled molding material. Therefore, the PET two-layer stretch blow-molded container of the present invention does not have a risk of causing harm to the human body due to the recycled molding material, and does not affect the contents such as an unusual odor or deterioration. In addition, since the outer shell and the inner shell are made of PET as a molding material, when the inner shell is injection-molded,
The inner shell is integrally heat-sealed to the inner surface of the outer shell. In the two-layer preform, the average thickness of the outer shell is D1.
And when the average thickness of the inner shell is D2,
Since D1: D2 = 5.5: 0.8 to 0.8: 3.5, the moldability is good, and no whitening phenomenon occurs in the shell.

[0015]

The PET double-layer stretch blow-molded container of the present invention is manufactured by regulating the ratio of the average thickness of the outer shell to the average thickness of the inner shell when manufacturing a two-layer preform. Therefore, the moldability is good, and no whitening phenomenon occurs in the shell. Therefore, the appearance is good.

Further, in the PET two-layer stretch blow molding of the present invention, the outer layer shell which does not come into contact with the contents uses a molding resin regenerated from PET waste, and the inner layer shell which comes into contact with the contents contains PET. Since virgin molding resin is used, there is no danger of harm to the human body and no adverse odor or deterioration of the contents.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the structure of an example of a two-layer preform.

[Explanation of symbols]

 10 Double-layer preform 11 Gate 100 Outer shell 110 Gate through hole 200 Inner shell

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) // B29K 67:00 B29L 9:00 105: 26 22:00 B29L 9:00 B65D 1/00 BRFB 22: 00 BSF (72) Inventor Takekuni Seki 1-5-1, Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd. (72) Inventor Kiyoshi Wada 1-5-1, Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd. F term (reference) 3E033 AA01 BA18 BB08 DA04 FA02 FA03 GA02 4F208 AA24 AA50 AG03 AG07 AH55 AR12 LA02 LA04 LB22 LG26 LG28

Claims (5)

[Claims] 1. The method according to claim 1, wherein the outer layer shell is brought into close contact with the cavity surface of the female mold of the injection mold for the preform, and is fixed.
A PET biaxially stretch blow-molded container in which an inner shell is integrally injection-molded inside the outer shell to produce a two-layer preform, and the two-layer preform is biaxially stretch blow-molded. The molding material is a recycled molding material, the molding material of the inner shell is a molding material of virgin, and the two-layer preform has an average thickness of the outer shell of D1, and an average thickness of the inner shell. Thickness D
2. A PET two-layer stretch blow-molded container, wherein D1: D2 = 5.5: 0.8 to 0.8: 3.5. 2. The method according to claim 1, wherein the outer layer shell is fixed to the cavity surface of the female mold of the injection mold for the preform in advance.
A PET biaxially stretched blow-molded container in which an inner shell is integrally injection-molded inside the outer shell to produce a two-layer preform, and the two-layer preform is biaxially stretch blow-molded. The molding material is a molding material obtained by mixing a recycled molding material and a virgin molding material, the molding material of the inner shell is only the virgin molding material, and the two-layer preform is formed of the outer shell. When the average thickness is D1 and the average thickness of the inner shell is D2, D1: D2 = 5.5: 0.8 to 0.8: 3.5. PET double-layer stretching. Blow molded container. 3. The PET double-layer stretch blow molded container according to claim 1, wherein the recycled molding material is a pulverized material obtained by pulverizing PET waste. 4. The PET double-layer stretch blow-molded container according to claim 1, wherein the recycled molding material is a pellet obtained by pelletizing a pulverized material of PET waste. 5. The PET two-layer stretch blow molded container according to claim 3, wherein the recycled molding material has an intrinsic viscosity increased by solid-state polymerization.