JP2011116385A - Synthetic resin-made double container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin-made double container which has a container wall, etc., that is thickened to offer fine texture, well maintains the quality of a content article, and suppresses a whitening phenomenon to offer fine appearance. <P>SOLUTION: An inner container portion (8) is formed by injection molding using a crystalline synthetic resin material, such as PET resin, as a molding material. An outer container portion (9) is formed on the outer surface of the inner container portion (8) by injection molding using a noncrystalline synthetic resin material, such as cyclohexanedimethanol-based polyester resin, as a molding material. The inner container portion (8) comprises a fitting portion (7) fitted with a lid. The outer container portion (9) is attached integrally to the outer surface of the part of inner container portion (8) not including the fitting portion (7). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a synthetic resin double container for storing cosmetics and the like. More specifically, the container wall and the like can be formed thick to improve the texture, and the quality of the container can be maintained well, and the whitening phenomenon can be prevented. The present invention relates to a synthetic resin double container capable of suppressing generation and obtaining a good appearance.

  Containers for storing cosmetics and the like are required to have excellent chemical resistance so that the stored items do not change in quality, and also have good aesthetics and texture. For this reason, glass containers have been frequently used, but in recent years, synthetic resin containers have also been used because of their ease of color and decoration. In order to create a profound feeling, it is desirable to thicken the container wall and bottom of these synthetic resin containers. However, if the container wall is thick, it takes cooling time to form by injection molding, etc. There is a problem that productivity cannot be easily improved.

  Conventionally, in order to solve the above problems and efficiently produce, after forming the inner container part by injection molding, a method of integrally molding the outer container part outside the inner container part has been proposed (for example, (See Patent Document 1, hereinafter referred to as the prior art). That is, in this prior art, two general type injection molding machines are used. Then, after the inner container part is first formed by one injection molding machine, the inner container part is mounted on the core mold of the other injection molding machine, and the outer container part is integrally formed outside the inner container part. It is formed.

Registered Utility Model No. 3114093

  In the above prior art, the same resin material is used so that the outer surface of the inner container part and the inner surface of the outer container part are fused and integrated with each other. However, for example, when formed of a crystalline synthetic resin material such as polyethylene terephthalate resin (hereinafter also referred to as PET resin), crystallization proceeds during cooling, and, for example, clouding occurs around a gate from an injection molding machine. There was a problem that a whitening phenomenon occurred and the appearance was poor.

  The technical problem of the present invention is to solve the above-mentioned problems, to obtain a good texture by forming a thick container wall and the like, to maintain a good quality of the contents, and to suppress the occurrence of whitening phenomenon. An object of the present invention is to provide a double container made of synthetic resin, which can have a good appearance.

In order to solve the above problems, the present invention will be described as follows, for example, based on FIGS. 1 and 2 showing an embodiment of the present invention.
That is, the present invention relates to a synthetic resin double container, and an amorphous synthetic resin material is used as a molding material on the outer surface of the inner container portion (8) formed by injection molding using a crystalline synthetic resin material as a molding material. The outer container part (9) is formed integrally with the inner container part (8) by injection molding.

  Since the outer container part is formed by injection molding, the outer container part can be well integrated with the inner container part, and the container wall and bottom as a whole are made thick and heavy. At this time, since the inner container portion is formed of a crystalline synthetic resin material, the portion exposed on the inner surface of the container is excellent in chemical resistance. However, the crystalline synthetic resin material may be crystallized during the cooling of the injection molding and may cause a whitening phenomenon around the gate. However, the gate portion is provided on the outer surface of the inner container portion, and the outer container portion is formed on the outer surface by injection molding. Therefore, the above whitening phenomenon occurs on the outer surface of the inner container portion. Even so, during the injection molding, the outer container part is heated with the molten resin, and the whitening phenomenon is eliminated. On the other hand, since the outer container portion is formed of an amorphous synthetic resin material, there is no possibility of causing a whitening phenomenon at the time of cooling regardless of the cooling conditions at the time of molding, and a good appearance can be obtained.

  The above-mentioned crystalline synthetic resin material and non-crystalline synthetic resin material are not limited to specific synthetic resin materials, but a combination with good compatibility between them is preferable. For example, when the crystalline synthetic resin is a PET resin and the non-crystalline synthetic resin is a cyclohexane dimethanol-based polyester resin, the cyclohexane dimethanol-based polyester resin is excellent in compatibility with the PET resin. The above injection molding is preferable because it can be satisfactorily integrated. Moreover, the PET resin and cyclohexanedimethanol-based polyester resin have the advantage that the gloss, brightness, and transparency of the container surface can be approximated to those made of glass, and a better texture can be obtained. .

  The cyclohexanedimethanol-based polyester resin is, for example, a polyester composed of a terephthalic acid unit, an ethylene glycol unit, and a cyclohexanedimethanol unit, and the molar ratio of the ethylene glycol unit is greater than the molar ratio of the cyclohexanedimethanol unit. A large PETG resin, a polyester comprising a terephthalic acid unit, an ethylene glycol unit and a cyclohexanedimethanol unit, wherein the molar ratio of the ethylene glycol unit is smaller than the molar ratio of the cyclohexanedimethanol unit, PCTA resins composed of isophthalic acid units and cyclohexanedimethanol units are included and are available from Eastman Chemical Company.

  The inner container portion and the outer container portion are not limited to those having a specific shape, but the inner container portion is formed with a mounting portion with a lid, and the outer container is formed on the outer surface excluding the mounting portion. If the parts are integrated, the mounting part can be easily formed into an arbitrary shape, for example, a shape having a male screw part on the outer peripheral surface, and the inner container part and the outer container part can be integrated well. It is preferable.

  In this case, if an undercut portion having a smaller diameter than the outer diameter of the mounting portion is formed between the mounting portion and the upper surface of the outer container portion, the outer container portion is attached to the outer surface of the inner container portion. When injection molding, the inner container part can be held in the core side mold by using this undercut part, and therefore, the synthetic resin double container after molding can be easily taken out from the mold.

  The crystalline synthetic resin material and the non-crystalline synthetic resin material can be arbitrarily set in coloring, transparency, and the like. However, if at least one of these materials is composed of a colored or colorless transparent material and a diffusing material is mixed, the light transmitted through the container wall and the like is diffused, so mat processing, blast processing, etc. can be applied to the container surface Without applying, it is possible to make a frosted glass-like container, and it is preferable that a high-quality container can be obtained at low cost. Specific examples of the diffusing material include calcium carbonate, polymer fine particles such as a crosslinked polymethyl methacrylate resin and a crosslinked polystyrene resin, and the like, as long as it can scatter light. It is not limited.

  Since the synthetic resin double container of the present invention is configured and operates as described above, the following effects can be obtained.

(1) Since the inner container part and the outer container part are integrated with each other, the container wall and the bottom part can be formed thick as a whole, and the texture can be improved by giving a sense of weight and giving a high-class feeling.
(2) Since the inner surface of the container is formed of the crystalline synthetic resin material of the inner container part, it has excellent chemical resistance, and can prevent the possibility that the contents such as cosmetics are altered by the molding material of the container, The quality of the contents can be maintained well.
(3) Since the inner container part is formed of a crystalline synthetic resin material, there is a risk of whitening phenomenon during cooling, but since the outer container part is heated and melted during injection molding, the whitening phenomenon can be eliminated. In addition, since the outer container portion is formed of a non-crystalline synthetic resin material, there is no possibility of causing a whitening phenomenon during cooling regardless of the cooling conditions during molding. As a result, a good appearance can be obtained.

It is a partially broken front view of the synthetic resin double container showing an embodiment of the present invention. It is the partially broken figure which expanded the mounting part vicinity of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, this synthetic resin double container (1) has a housing part (2) in which cosmetics and the like are housed, and a container wall (3 ) And a bottom (4), and is formed in a wide-mouthed container shape with a wide opening (5) opened on the top surface. A mounting portion (7) having a male screw (6) on the outer peripheral surface is formed around the opening (5), and a lid (not shown) is screwed to the mounting portion (7).

  As shown in the sectional view of FIG. 1, the synthetic resin double container (1) includes an inner container part (8) and an outer container part (9) outside the inner container part. The inner container part (8) is provided with a container wall part (8a) and a bottom part (8b) so as to surround the housing part (2), and the mounting part is located above the container wall part (8a). Part (7). The inner container portion (8) is formed by injection molding using, for example, a crystalline synthetic resin material such as PET resin as a molding material, and is translucent colored in a predetermined color, for example.

  On the other hand, the outer container part (9) is an outer surface of the inner container part (8) excluding the mounting part (7), that is, the container wall part (8a). It is formed by injection molding so as to be fused and integrated with the outer peripheral surface and the lower surface of the bottom portion (8b). The outer container part (9) is made of a non-crystalline synthetic resin material. Specifically, for example, cyclohexane dimethanol-based polyester resins such as PETG resin, PCTG resin, and PCTA resin are used. A diffusing material is blended with a colored transparent molding material.

  The above-mentioned synthetic resin double container (1) has a high-class appearance because the inner container part (8) is viewed through the polished glass-like outer container part (9) when viewed from the outside. Since both are integrated, the container wall (3) and the bottom (4) are formed thick, and there is a feeling of weight. Furthermore, although this double container (1) is made of synthetic resin, it does not cause whitening around the gate (10) of the outer container part (9) and has a good appearance.

  In this embodiment, the inner container part (8) is made of a colored translucent material, and the outer container part (9) is made of a colorless and transparent material mixed with a diffusing material. However, in the present invention, the inner container portion (8) and the outer container portion (9) may be formed of materials colored in the same color or materials colored in arbitrary colors. One or both may be formed of a colorless or colored transparent material. The above diffusing material may be blended in either or both of the inner and outer container parts (8, 9), or the blending of the diffusing material may be omitted.

The synthetic resin double container (1) is manufactured by using two injection molding machines, for example, by the following procedure.
First, after molding the inner container part (8) using the above crystalline synthetic resin material as a molding material by one injection molding machine, the mold of the injection molding machine is opened and the inner container part (8 ). Next, the inner container part (8) is attached to the core mold of the other injection molding machine, and the above amorphous synthetic resin material is used as a molding material on the outer surface of the inner container part (8). The outer container part (9) is molded. At this time, the outer surface of the inner container (8) is heated with the molten molding material of the outer container part (9). For this reason, even if a whitening phenomenon occurs on the outer surface of the inner container (8) when it is molded, the outer surface may be whitened by the above heating during the molding of the outer container part (9). It will be resolved. On the other hand, since the molding material is an amorphous synthetic resin material around the gate (10) of the outer container portion (9), there is no possibility of whitening during cooling.

  As shown in FIG. 2, an undercut portion (11) having a smaller diameter than the outer diameter of the mounting portion (7) is provided between the mounting portion (7) and the upper surface of the outer container portion (9). It is formed in a shape. When molding the outer container part (9), the inner container part (8) is securely held by the core side mold (12) by the undercut part (11). When the container is opened, the molded synthetic resin double container (1) is easily released from the cavity side mold (13) and taken out.

  The synthetic resin double container described in the above embodiment is illustrated to embody the technical idea of the present invention, and the shape, dimensions, structure, etc. of each part are limited to those of this embodiment. Instead, various modifications can be made within the scope of the claims of the present invention.

  For example, in the above embodiment, the outer container part is formed so as to surround the container wall part of the inner container part, which is preferable because the outer container part and the inner container part can be integrated well. However, in the present invention, the inner container portion and the outer container portion are not limited to those of this embodiment, and can be formed in an arbitrary shape. For example, it is preferable that the container wall has a substantially uniform thickness in the circumferential direction because distortion at the time of molding is suppressed, but the outer circumferential surface is formed in an arbitrary shape such as a polygonal shape, and is uniform in the circumferential direction. Any thickness may be used. The mounting portion can be formed in the outer container portion.

  In the above embodiment, the inner container portion is formed of PET resin, and the outer container portion is formed of PETG resin, PCTG resin, PCTA resin, or the like. However, in this invention, you may form an inner container part and an outer container part with another crystalline synthetic resin material. Needless to say, the items to be accommodated in the accommodation unit are not limited to cosmetics.

  The synthetic resin double container of the present invention can be formed with a thick container wall and the like to have a good texture, maintain the quality of the contained material well, and suppress the occurrence of the whitening phenomenon to obtain a good appearance. Therefore, it is particularly suitable for containers for storing cosmetics and the like, but is also suitable for containers for storing other items.

DESCRIPTION OF SYMBOLS 1 ... Synthetic resin double container 7 ... Mounting part 8 ... Inner container part 9 ... Outer container part
11 ... Undercut part

Claims (5)

  On the outer surface of the inner container portion (8) formed by injection molding using a crystalline synthetic resin material as a molding material, the outer container portion (9) using an amorphous synthetic resin material as a molding material is formed by injection molding. A synthetic resin double container characterized by being formed integrally with the inner container part (8).   The double container made of synthetic resin according to claim 1, wherein the crystalline synthetic resin is a polyethylene terephthalate resin and the non-crystalline synthetic resin is a cyclohexanedimethanol-based polyester resin.   The inner container part (8) includes a mounting part (7) with a lid, and the outer container part (9) is integrated with an outer surface excluding the mounting part (7). The synthetic resin double container according to claim 2.   The undercut portion (11) having a smaller diameter than the outer diameter of the mounting portion (7) is formed between the mounting portion (7) and the upper surface of the outer container portion (9). Synthetic resin double container.   5. The structure according to claim 1, wherein at least one of the crystalline synthetic resin material and the non-crystalline synthetic resin material is formed of a colored or colorless transparent material and a diffusing material is blended. Double container made of synthetic resin.

Images