JP3097004B2 - Multilayer blow molded bottle made of synthetic resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin multilayer blow-molded bottle blow-molded from a multi-layer parison.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 53-15432 is known as a prior art of a synthetic resin multilayer blow molded bottle. In this prior art, the joint formed by pinch-off on the bottom of a bottle blow-molded from a multi-layer tubular parison is formed as a tapered ridge projecting outward, so that each layer is joined at the joint. It is substantially continuous.

[0003]

However, in the above-mentioned prior art, the inner layer and the outer layer can be made continuous and the outer side of the inner layer can be covered with the outer layer at the joint. The thickness of the outer layer covering the continuous inner layer is extremely thin, so that the inner layer is made a dark color such as opaque black for the purpose of shading the contents, and the outer layer is a light color such as opaque white to improve the product image. In such a case, the dark color of the inner layer is visually recognized as a line on the end face of the projecting portion, and there is a problem that the appearance of a bottle as a product is significantly deteriorated.

Accordingly, the present invention has been made to solve the above-mentioned problems in the prior art, and it is an object of the present invention to position an inner layer sufficiently inside an outer layer at a joint formed by pinch-off. It is a technical object of the present invention to prevent the appearance of the appearance from being deteriorated due to the appearance of the dark color of the inner layer on the outer surface formed by the bright color of the outer layer at the projecting tip of the joint.

[0005]

According to the present invention, there is provided a bottle blow-molded from a tubular parison having an inner layer of opaque dark color and an outer layer of opaque light color. The joint formed in the shape of a ridge on the outer surface of the bottom by pinch-off of the bottle is a ridge having a substantially trapezoidal cross section. The thickness should be approximately equal to the thickness, the tip thickness should be approximately half the thickness of the parison, the base thickness should be approximately two-thirds the thickness of the parison, A certain relief angle is in the range of approximately 8 to 15 °.

[0006]

The joint formed on the outer surface of the bottom of the bottle in a ridge shape by pinch-off has a thickness of about two thirds or less of the thickness of the parison, that is, a flat crushed state. Since it is set to less than about one third of the thickness of the parison,
At the time of forming the joint, approximately two-thirds of the softened resin material of the parison part formed at the joint is extruded from the part formed at the joint.

[0007] As described above, in the joint portion which is pressed and formed in a ridge shape by pinch-off, approximately two-thirds of the softened resin material of the parison portion formed in the joint portion is formed in an adjacent portion other than the joint portion. Although it is extruded, the front and rear surfaces of the joining portion have a cross-sectional shape that is widened toward the base end side at a relief angle of about 8 to 15 °, so that the release direction of the softened resin material generated by pressing, that is, the flow displacement The direction is substantially restricted to the proximal direction of the joint.

Since the flow displacement of the softened resin material at the time of press-molding the joint is generated by pressing the cooled mold, the resin material portion in contact with the mold surface, that is, the outer layer portion is formed by the mold. Due to the decrease in fluidity due to the temperature decrease due to contact with the mold and the contact resistance of the mold, the flow displacement is difficult, and the resin material part located inside, that is, the inner layer part, maintains high fluidity. It will receive the pushing force in the state where it did.

For this reason, in the joint, substantially all of the inner layer is pushed out toward the base end of the joint, and the inner layer is located largely inside from the distal end surface of the joint.

The reason why the relief angle of both the front and rear surfaces of the joint is set to 8 to 15 ° is that if the relief angle is less than 8 °, it is not possible to give a sufficient flow movement force by pressing against the softening resin material. If the relief angle is 15 ° or more, it is not possible to obtain a sufficient flow movement distance due to the pressing of the softening resin material.

[0011] Further, by making the height width of the joint substantially equal to the thickness of the parison, the thickness of the joint in the range of the relief angle on both the front and rear surfaces of the joint and the thickness of the parison can be reduced. Within the ratio range, the retreat amount of the inner layer caused by the pressing can be set to a sufficient value.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a front view of a bottle 1 according to the present invention. In the bottle 1, a bottom 3 is continuously provided at a lower end of a cylindrical body 2 having a mouthpiece integrally connected to an upper end thereof. The bottom part 3 is provided with a bottom wall 4 which is recessed inside the body part 2.
And a leg wall 5 which is located around the bottom wall 4 to form a "seat", and a joint 6 formed by pinch-off in the form of a lateral ridge at the center of the outer surface (lower surface) of the bottom wall 4. Have been.

The bottle 1 has a multilayer structure (see FIG. 2) having an inner layer 8 and an outer layer 9 on the wall, and the inner layer 8 is formed of an opaque black colored virgin PP material on the inner surface. The inner layer 8a includes an inner layer 8b formed of a recycled PP material colored opaque black, and the outer layer 9 includes:
An outer surface outer layer 9a formed of a transparent PP material and a middle outer layer 9b formed of an opaque white colored PP material in order to exhibit excellent gloss on the surface of the bottle 1. I have.

The thickness of the middle and outer layers 9b is 0.584.
mm, and the outer surface outer layer 9a has a thickness of the middle outer layer 9b.
Is less than half of 0.27 mm, and the layer thickness of the inner layer 8 is a value (specifically, 62
The parison has a wall thickness of 1.483.
mm.

With respect to the thickness of each layer, the dimensions of each part of the joint 6 are such that the height h is 1.5 mm, which is slightly larger than the thickness of the parison, and the tip thickness w1 is the thickness of the parison. Is 0.7 mm, which is half or less of the above, the base end portion thickness w2 is 0.9 mm, and the relief angle θ is 10 °.

As can be seen from FIG. 4, in the joint 6, the projecting end of the inner layer 8 has a sufficient value from the tip of the joint 6 to the inside (approximately equal to the thickness w1 of the tip of the joint 6). ), The black color of the inner layer 8 passes through the white color of the outer layer 9 and is not visible from the outside of the bottle 1 at the joint 6.

As shown in FIGS. 2 and 3, a portion of the leg wall 5 which is located on the extension of the joint 6 is removed so that the escape groove 7 is formed.
Is formed by setting the height h of the joint 6 to the height
In order to be able to be formed equally over the entire length of the sheet.

[0018]

Since the present invention has the above-described structure, the following effects can be obtained. Since the inner layer at the joint can be located sufficiently inside, the dark color of the inner layer does not penetrate through the outer layer and is visible on the distal end surface of the joint, so that the color of the inner layer changes to the outer surface of the bottle. As a result, the appearance can be completely prevented from being deteriorated.

Since the flow displacement of the inner layer at the joint is necessarily achieved by pinch-off in ordinary blow molding, it can be accurately and reliably achieved by a conventional molding method without employing a special molding method. can do.

[Brief description of the drawings]

FIG. 1 is an overall front view showing an embodiment of the present invention.

FIG. 2 is a partially enlarged bottom side view of the embodiment shown in FIG. 1;

FIG. 3 is a bottom view of the embodiment shown in FIG. 1;

FIG. 4 is an enlarged vertical sectional side view of a joint in the embodiment shown in FIG. 1;

[Explanation of symbols]

1; bottle 2; trunk 3
Bottom 4; bottom wall 5; leg wall 6
Joining part w1; tip part thickness w2; base part part thickness h.
Height width θ; relief angle 7; relief groove 8
Inner layer 8a; inner surface inner layer 8b; middle inner layer 9;
Outer layer 9a; outer surface outer layer 9b; middle outer layer

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65D 1/09

Claims (1)

(57) [Claims] 1. A bottle (1) blow-molded from a tubular parison having an inner layer (8) of an opaque dark color and an outer layer (9) of an opaque light color. Connect the joint (6) shaped like a ridge to the height and width (h).
Is approximately equal to the thickness of the parison, the tip thickness (w1) is approximately half of the thickness of the parison, the proximal thickness (w2) is approximately two-thirds of the thickness of the parison, and A synthetic resin multilayer blow-molded bottle in the form of a ridge having a substantially trapezoidal cross section, wherein the relief angle (θ), which is the angle of inclination of the front and rear surfaces, is in the range of approximately 8 to 15 °.