JPS5843308B2 - Biaxially stretched container - Google Patents

Description

[Detailed description of the invention] The present invention 11 relates to a biaxially stretched container made of synthetic resin.

, Conventional containers made of synthetic resin generally have letters, patterns, etc. attached to them by printing means using ink, but containers with letters, patterns, etc. attached to them by means using ink, including the above-mentioned printing means. Conventionally, there has been no satisfactory container for displaying letters, patterns, etc., as the letters, patterns, etc., tend to peel off or disappear, and there are also pollution problems due to the solvent in the ink.

Therefore, the present invention IJ was developed as a result of studies in view of the above-mentioned difficulties, and instead of using thermoplastic resins such as transparent polyethylene terephthalate, the parison is molded in the circumferential direction (in this case, the peripheral wall is formed into irregular thickness such as uneven stripes). By rapidly cooling one of the inner and outer peripheries and slowly cooling the other, a whitening phenomenon is caused in the thick inner part, and the parison formed in this way is biaxially stretched to create a striped pattern etc. on the peripheral wall. The purpose is to make effective use of the properties of crystalline resin to create a non-polluting material that can be easily molded to create a striped pattern that is clear and never peels off. The purpose is to provide a biaxially stretched container.

Hereinafter, the present invention will be explained in detail with reference to the drawings showing one embodiment.

Container A of the present invention is molded from a thermoplastic crystalline synthetic resin such as transparent polyethylene terephthalate, which has high tensile strength, high toughness, and high transparency.

As a molding means, the parison 1, which has been molded in advance by injection molding means as a pre-molding step, is placed in the mold 2 and cavity 3 of a blow molding machine, and compressed air is blown into the parison from the mandrel 4. Similar to conventional biaxially stretched containers, the parison is stretched biaxially and formed into a desired shape that follows the inner shape of the container.
In accordance with the present invention, the following parison is used.

As illustrated in FIGS. 2 and 3, the parison 1 has a bottomed shape with a circular cross-sectional outer circumferential shape and an inner wall surface 5.
1. Approximately V-shaped irregularities 6, 7, . Molded thickly.

This parison is formed by rapidly cooling the outer wall surface and slowly cooling the inner wall surface.By changing the cooling mode of the inner and outer walls, the peripheral wall 8 of varying thickness can be formed by thinner portions 9. The thick part 10 is cooled before the thick inner part 10, and since the inner wall surface of the thick part 10 is slowly cooled, the forming heating temperature (J remaining in the core part) is gradually dissipated and finally the thick part 10 is completely cooled.

However, the difference in the cooling rate between the thin wall portion 9 and the thick inner portion 10 (thus, when the thin wall portion is cooled, the thick inner portion, which still has a residual thermal temperature, has a residual temperature (this means that it is substantially heated). Therefore, due to some heat, the segments of disordered long chain molecules of the high polymer form a crystalline arrangement, and as a result, the physical properties change, that is, a whitening phenomenon occurs, and each thick portion 10... ... Inside is whitening 11 ...
··do.

Also, since the uneven stripes 6, 7& on the inner wall of the parison are arranged vertically, and as a result, the thick portions 10 are arranged vertically, the whitening phenomenon naturally occurs in the vertical direction. It appears as shown in Figure 2.

Therefore, by biaxially stretching and molding the pre-formed parison in this way using blow molding means in a mold as shown in Figure 4, the whitened 11 area can also be stretched at the same ratio as the other parts. Therefore, a container A with a striped pattern 12 appearing on the peripheral wall a as shown in FIG. 1 is obtained.

In addition, the parison 1 is formed by forming the peripheral wall 8 into a modified thickness, rapidly cooling the outer wall,
By slowly cooling the inner wall, a whitening phenomenon can be obtained in the thick part, and it can be easily molded without adding any special molding means. The container A is biaxially stretched by blow molding means of
can be molded.

The whitening 11 to reveal the stripe pattern 12 above is
Since it is made to appear by utilizing the characteristics of crystalline resin, it will never peel off or disappear due to chemical changes caused by the contents or the like.

In addition, the parison in the illustrated example has an uneven stripe on the inner wall surface and a modified thickness on the peripheral wall, but on the other hand, it is also possible to make the outer surface of the peripheral wall have uneven stripes, the inner shape is circular, and the peripheral wall has a modified thickness. , the inner wall is rapidly cooled, and the outer wall (1) is slowly cooled.

Further, the container of the present invention (1) may have a cylindrical shape with a constant body diameter as shown in the illustrated example, but it goes without saying that it may have an irregular body diameter and be deformed.

As is clear from the above, the biaxially stretched container 1 of the present invention has a whitening phenomenon obtained by utilizing the properties of the crystalline resin of polyethylene terephthalate, and a property of high transparency of polyethylene terephthalate (therefore, it is clear and peelable). , has the advantage of providing a container with a swim-like striped pattern that never disappears.

Furthermore, in the container of the present invention, the peripheral wall of the parison is formed into a modified thickness as a pre-process of biaxial stretching, and the cooling means for the inner and outer peripheries is rapid cooling and slow cooling, thereby preventing the whitening phenomenon in the thick portion. The formed parison can be formed by a known biaxial stretching method without using any special equipment or means, making it easy to form and mass-produce (it can be produced at low cost and is suitable for this purpose).
Since the striped pattern is a phenomenon caused by crystallization of the resin, it is a beneficial invention as it does not require any additives or solvents and is non-polluting.

[Brief explanation of the drawing]

The attached drawings show actual cases of the present invention, and FIG. 1 is a partially cutaway front view of a biaxially stretched container of the present invention, and FIG. FIG. 3 is a cross-sectional view taken along the line DI-1 in FIG. 2, and FIG. 4 is a cross-sectional view showing a mode in which the container of the present invention is biaxially stretched and molded. 1... ...Parison, 8...Peripheral wall of parison, 10...Thick wall portion, 11...Whitened portion, 12...Stripe pattern.

Claims (1)

[Claims] 1 A parison 1 is made of a thermo-q plastic resin such as transparent polyethylene terephthalate and is formed as a pre-process before being stretched on two wheels.A peripheral wall 8 is formed to have a variable thickness in the circumferential direction, and one of the inner and outer peripheries (1) is rapidly cooled. However, by slowly cooling the other side, a whitening phenomenon is caused in the thick wall portion 10, and such a parison is biaxially stretched to form a striped pattern 12, etc. on the peripheral wall portion t. A biaxially stretched container.