JP2000071320A - Plastic container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily prevent a container from breaking even under a severe falling condition only by changing the shape of a label without thickening the wall of the container by a method wherein the under surface of the edge part of the in-mold label to be made into an integral body with the container is made into a curved surface. SOLUTION: When a molding, in which an in-mold label is used, is carried out, the under surface side (a container side) of the edge part of the label to the side to weld is formed to be a curved surface. Concretely, the in-mold label 1 having the thickness B is made into an integral body with a plastic container 2 having the thickness A and the under surface side of the edge part of the in-mold label is made into a curved surface having its corner with a radius of curvature R. As a result, the direction of the edge face, to which a stress works strongly becomes the tangent direction of a circle having the radius of R and oblique to a container main body. Actually, the preferable radium of curvature R satisfies an inequality B<=R<=2B. Further, when R>=0.1 mm is employed, and enough strength can be obtained under the condition that the thickness of the label is 1/5 or less of the wall thickness of the container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic container in which a label is integrated at the same time as blow molding, and more particularly to a plastic container in which the edge of the label is not peeled off even under a severe condition.

[0002]

2. Description of the Related Art As a method of attaching a label to a plastic container, a method of attaching a label to the plastic container by applying a paste to the back of the label, a method of attaching a seal-like label with an adhesive, and a method of forming a plastic container At the same time, there is a method using an in-mold label in which a label is inserted and integrally molded. By the way, the method using the in-mold label is used for a plastic container used for so-called water around a humid place such as a bath or a toilet, or a plastic container for contents used with water such as a car shampoo, The demand is extremely high because there is no peeling of labels due to. In addition, since this type of container has a single-piece label, it prevents damage to the label due to external impact, is less likely to be degraded by the environment of the label itself, and has a clear appearance. There is. However, depending on the plastic material used for the container, cracking may occur under severe drop conditions.

[0003] In the method using the in-mold label, the label covers a large part of the surface of the plastic, which limits the thickness of the container itself. Moreover, since there is no adhesive layer between the label end surface and the container surface, sufficient adhesive strength cannot be obtained. Therefore, the drop strength of the formed plastic container is weak as a method of bonding a label to the surface of the container, and the disadvantage that the container is damaged when dropped under severe drop conditions is still recognized.

[0004] Due to this disadvantage, particularly in the case of a label having a complicated shape, the container sometimes bends considerably locally when it is dropped, and it is difficult to use an in-mold label for a plastic container with high strength. And
Even if there is a desire to increase the label surface in appearance, there is a problem that the area and position with respect to the in-mold label are limited. In order to solve this, there is a method of increasing the thickness of the container, but there are cases where molding is difficult, and the content of the container is reduced and it is not economical.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a plastic container of an in-mold label system, which is capable of labeling without increasing the thickness of the container. An object of the present invention is to provide a plastic container having a label suitable for an in-mold label system which is not easily damaged even under severe drop conditions only by changing the shape.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the invention of claim 1 is a plastic container for integrating a label simultaneously with blow molding. The plastic container is characterized in that the lower surface of the edge of the mold label is curved.

According to a second aspect of the present invention, there is provided a plastic container for integrating a label simultaneously with blow molding,
2. The plastic container according to claim 1, wherein B≤ (1/5) A, where B is the thickness of the label and A is the thickness of the body of the plastic container. .

According to a third aspect of the present invention, there is provided a plastic container for integrating a label simultaneously with blow molding.
The plastic container according to claim 1 or 2, wherein when the edge of the in-mold label integrated with the container has a radius of curvature R, the range is B ≦ R ≦ 2B. is there.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention did not use a label whose bottom surface (container side) at the edge of the label had a right angle when performing molding using an in-mold label, that is, on the side to be bonded. It has been found that by forming the lower surface side (container side) of the edge of the label as a curved surface (predetermined curvature R), it is possible to mold a plastic container that can withstand a drop under severe conditions. Further, regarding the relationship with the thickness of the plastic container, it has been found that a container having sufficient performance can be obtained if the thickness of the label is about 1/5 or less of the thickness of the container.

[0010] By changing the label shape of the in-mold method, the drop test can be cleared for a bottle having a complicated shape, which could not clear the conventional drop test. Since there is basically no adhesive layer between the edge of the label and the surface of the plastic container, the adhesive strength between the plastic container and the edge of the label is weak. If the bottle suddenly receives an impact due to dropping or the like, stress concentrates on the end surface, and the container easily cracks and breaks along the label when the strength exceeds the limit.

FIG. 1 is a conceptual explanatory view showing a cross section of a plastic container having an in-mold label of the present invention. An in-mold label 1 having a thickness B is integrated with a plastic container 2 having a thickness A. If the lower surface of the in-mold label edge is curved and the corner has a radius of curvature R, the direction of the end of the end surface where the stress acts strongly becomes the tangential direction of the circle having the R and acts obliquely on the container body. (Or the stress component perpendicular to the vessel wall is reduced). In principle, it is sufficient to take R as large as possible, but it is impossible to take R infinitely due to the limitation of the technology for producing a label, and the problem that the non-contact surface of the label end face increases if R becomes extremely large. Actually, it has been found that R should satisfy B ≦ R ≦ 2B.

In addition, actually, not only the radius of curvature of the edge of the label but also the thickness of the label material on which the stress acts and the label material measured from the end face of the plastic container are important. Ideally, a label having a minimum thickness is used. Is good. Also, if the material is harder and harder to deform than the bottle material (high rigidity), a phenomenon occurs in which strain concentrates on the label side and cracks occur. Actually, since there is a need to provide an adhesive layer for inserting the label into the mold and bonding the container, there is a restriction on manufacturing to reduce the thickness of the label, but when R ≧ 0.1 mm ,
It has been found that sufficient strength can be obtained if the thickness of the label is 1/5 or less of the thickness of the container.

[0013]

Next, specific embodiments of the present invention will be described in detail below.

<Embodiment 1> In a drop test of a container as shown in FIG. 2, erect → front left side → front right side → surface →
Table 1 shows the results of a drop test using a label having a rectangular cross section and a label having a changed curvature radius R of the curved surface on the lower surface side of the edge when the cycle of the back surface is performed 10 times from an altitude of 2 m. Show.

[0015]

[Table 1]

According to this embodiment, the radius of curvature R is 0.07 to
It can be seen that good results are obtained when 0.1 mm, that is, B ≦ R ≦ 2B.

<Embodiment 2> In a drop test of a container as shown in FIG. 2, erecting → front left side → front right side → surface →
Table 2 shows the results of a drop test in which the thickness of the bottle was changed when the cycle of the back surface was performed 10 times from an altitude of 2 m. Bottle material HDPE Label material CPP / PE

[0018]

[Table 2]

According to this embodiment, the thickness of the container is 0.35 mm.
It can be seen that good results are obtained when B ≦ (Ｂ) A.

[0020]

Since the plastic container of the present invention has the above-described functions, it is a plastic container having an in-mold label, and the thickness of the lower surface of the edge of the label can be reduced without increasing the thickness of the container. It is possible to easily provide a plastic container having an in-mold label that is not damaged even under severe drop conditions by only changing the above.

[Brief description of the drawings]

FIG. 1 is a partial cross section of a plastic container of the present invention.

FIG. 2 is an overall side view showing one embodiment of the plastic container of the present invention.

[Explanation of symbols]

 1 Label 2 Plastic container

Claims (3)

[Claims] 1. A plastic container for integrating a label simultaneously with blow molding, wherein the lower surface of an edge of an in-mold label integrated with the container is curved. 2. A plastic container in which a label is integrated at the same time as blow molding, wherein B is the thickness of the label and A is the thickness of the body of the plastic container.
5) The plastic container according to claim 1, wherein the plastic container is A. 3. A plastic container in which a label is integrated at the same time as blow molding, wherein B ≦ R ≦ 2 when an edge of the in-mold label integrated with the container has a radius of curvature R.
The plastic container according to claim 1, wherein the range is B. 4.