JP5154992B2 - Method for producing injection molded body with hole for compact container and injection molded body with hole for compact container obtained thereby - Google Patents

Description

The present invention includes a method of compact case for the hole-injection molded body, to a compact container for the hole-injection-molded article obtained thereby.

  Many plastic products such as compact containers and lipstick containers are molded by injection molding. In such an injection-molded body, in order to perform hole processing, (1) a method of forming a hole at the same time as the injection molding using a mold, and (2) machining the molded body after injection molding. And a method of forming holes by water jet processing.

  However, in the method (1) of forming a hole using a mold, in general, it is difficult to make a fine hole having a diameter of less than 1.0 mm. In addition, since the resin material does not easily circulate around the periphery, there is a problem that welds are generated on the opposite side of the gate and the appearance is deteriorated, and the strength of the molded body is reduced. In addition, the method (2) of forming a hole in an injection molded body by post-processing has a problem that it takes time and production efficiency is poor. Moreover, in general, when an injection molded body with a relatively thin wall thickness (usually about 0.1 to 0.8 mm) is drilled later, scratches and cracks occur in the peripheral edge of the hole, resulting in many defective products. There is also the problem of doing.

In view of this, for example, an apparatus has been proposed in which a punch member that can be inserted into a cavity is provided in a mold, and injection molding can be performed while the hole is drilled by the punch member after injection filling (see Patent Document 1). ).
Japanese Patent Application Laid-Open No. 7-100879

  However, the above apparatus has a merit that holes can be simultaneously drilled at the time of injection molding, but there is a problem that the mold structure becomes complicated and it takes time to assemble and adjust the mold and the equipment cost is high. Further, since the punch member is removed from the hole while vibrating the hole after drilling, there is a problem that the inner peripheral surface of the hole is inevitably rough, and a separate finishing process is required for a beautiful finish.

The present invention has been made in view of such circumstances, and it is possible to easily and beautifully perform hole processing on an injection molded body for a compact container at low cost regardless of the size of the hole. The object is to provide an excellent injection molding product with a hole for a compact container that does not require a finishing treatment after molding, and to provide an injection molding product with a hole for a compact container obtained thereby.

In order to achieve the above object, the present invention is an injection molding method for obtaining a molded body having a plate-like portion with a thickness of 0.5 to 5.0 mm by injection molding a resin material using a predetermined mold. And a drilling step of forming a through hole by irradiating the plate-like portion of the molded body with a CO ₂ laser, and in the injection molding process, using the mold, the resulting molded body is penetrated. In the hole formation planned portion, a recess whose thinnest part is 0.1 to 0.8 mm is formed, and in the drilling step, the laser is directed toward the recess formed in the through hole formation planned portion. The first gist is a method for producing an injection molded body with a hole for a compact container in which a through hole is formed by completely removing the bottom surface portion of the recess by irradiation.

Further, the present invention is an injection-molded body with holes for a compact container obtained by the above-mentioned manufacturing method, and has a plate-like portion having a thickness of 0.5 to 5.0 mm, and a CO ₂ laser is provided on the plate-like portion. The injection molded body with holes for compact containers provided with through holes formed by irradiation is a second gist, and in particular, the injection molded body with holes for compact containers is a container body of a compact container. An injection molded body with a hole for a compact container having a recess for housing a cosmetic sponge, and a plurality of through holes formed by CO ₂ laser irradiation on the bottom surface of the recess as vent holes. This is the third gist.

And, among them, in particular, the injection molded body with a hole for a compact container is a container body of a compact container, and has a recess for accommodating an inner dish filled with cosmetics, For a compact container in which a through hole formed by CO ₂ laser irradiation is provided on the bottom surface of the concave portion as a hole for removing the middle pan in the concave portion by inserting the middle pan removing tool from the back side of the container body . The injection molded body with holes is a fourth gist, and the injection molded body with holes for compact containers in which the through holes formed by the CO ₂ laser irradiation are formed obliquely with respect to the thickness direction of the molded body. The gist of

In the production method of the present invention, in order to obtain an injection molded body with a hole for a compact container (hereinafter simply referred to as “injection molded body with a hole”) , first, through-hole formation is scheduled at the same time as injection molding for shaping the outer shape. A through-hole is formed by forming a very thin recess in the part, and after removing the mold, irradiating the CO ₂ laser toward the recess. According to this method, since the resin is melted and vaporized by the heat of the CO ₂ laser, the bottom surface portion of the recess is completely removed to form the through hole, so that the periphery of the through hole and the inner peripheral surface thereof are smooth. The appearance will be beautiful. Therefore, a finishing process such as that drilled by machining is unnecessary, and the production efficiency is high. Moreover, regardless of the diameter of the through-hole, there is an advantage that it is possible to easily drill a hole according to its size.

According to the manufacturing method of the present invention, since a very thin concave portion is formed in advance in the through hole formation planned portion by a mold, the time required for CO ₂ laser irradiation to the injection molded body can be reduced. Also, production efficiency is good. Moreover, at the time of molding the mold, the resin material flows around the portion for forming the concave portion, and the flow stagnate as in the case of forming a complete through hole. Therefore, no weld is generated, and the appearance and physical properties are not impaired.

  Moreover, the injection molded body with holes obtained by these manufacturing methods has a very beautiful appearance because the periphery and the inner peripheral surface of the formed through hole are smooth and no weld is generated. And since a distortion | strain etc. do not arise in a molded object with a drilling process, it has the stable intensity | strength as a whole, and can be used favorably over a long period of time.

  Note that, among the injection molded products with holes of the present invention, in particular, those in which the through holes are formed obliquely with respect to the thickness direction of the molded product are conventionally formed by a mold or in a mold. It is a shape that cannot be obtained by drilling with an incorporated punch member, and meets the design and functional requirements easily and at low cost.

  Next, the best mode for carrying out the present invention will be described. However, the present invention is not limited to the following embodiments.

  1A and 1B show an example in which the present invention is applied to a method of manufacturing a cover plate 6 (see FIG. 2) having a through hole 3 in the center. That is, first, by performing injection molding using a resin material and a mold, and removing the mold, a molded body 1 having a shape as shown in FIG. 1A is obtained. At this time, the thin recessed portion 2 is formed in the planned formation portion of the through hole 3 simultaneously with the shaping of the outer shape.

Next, as shown by an arrow P toward the concave portion 2 of the molded body 1, CO ₂ laser irradiation is performed, and the resin constituting the bottom surface of the concave portion 2 is melted and vaporized to be removed. As shown in b), the through hole 3 is formed. Thus, the target cover plate 6 can be obtained.

  As shown in FIG. 2, the molded body 1 (= cover plate 6) with the through hole 3 is overlaid on the upper surface of the lid body 5 having a protrusion 4 at the center, and the protrusion 4 is fitted into the through hole 3. It is integrated in the state which was made, and the lid | cover 7 of a compact container is comprised. The lid body 5 is provided with a connecting portion for hinge-connecting with the container body side of the compact container and an engaging portion with the container body (not shown).

  The lid 7 obtained in this way is interesting in terms of design, as the projection 4 of the lid body 5 can be seen through the central through hole 3.

According to the above manufacturing method, since the through hole 3 is formed in one place of the molded body 1 obtained by injection molding by the removal processing by the heat of the CO ₂ laser, finishing processing is performed by machining or the like after drilling. Despite not being applied, the periphery of the through-hole 3 and the inner peripheral surface thereof are smooth, and can be smoothly fitted with the protrusion 4 inserted through the inside.

Further, prior to the drilling step by the CO ₂ laser irradiation, since the thin concave portion 2 is formed by the mold in the portion where the through hole 3 is to be formed, CO ₂ to the molded body 1 is formed in the drilling step. The laser irradiation time is short and the production efficiency is good.

  In addition, when molding the mold, since the resin material flows around the portion for shaping the concave portion 2 at the bottom portion, a complete through hole is shaped in the mold. Thus, the flow is not stagnated and welds are not generated, and the appearance and physical properties are not impaired.

  In the above example, the resin material for obtaining the molded body 1 by injection molding is not particularly limited as long as it is conventionally used for injection molding, and may be appropriately selected depending on the shape, application, etc. These resin materials can be selected and used. For example, polyethylene (PE), polypropylene (PE), polystyrene (PS), acrylonitrile-styrene resin (AS), acrylonitrile-butadiene-styrene resin (ABS), methacrylic resin (PMMA), vinyl chloride resin (PVC), polyamide ( Thermoplastic resins such as PA), polyacetal (POM), polyethylene terephthalate (PET), polyether ether ketone (PEEK), polycarbonate (PC), polytetrafluoroethylene (PTFE), phenol resin (PF), melamine resin ( Examples thereof include thermosetting resins such as MF) and epoxy resin (EP). Among these, it is preferable to use a thermoplastic resin.

  And as for the molded object 1 in this invention, the part which forms the through-hole 3 must be a plate-shaped part with a thickness of 0.5-5.0 mm. That is, if the thickness is less than 0.5 mm, even if the through hole 3 is formed in that portion, the peripheral portion of the through hole 3 is too thin, the strength is weak, and damage is likely to occur. On the contrary, if the thickness exceeds 5.0 mm, the deep concave portion 2 must be formed as a pilot hole in the portion at the time of injection molding, and the resin is uniform around the concave portion 2 at the time of shaping. However, the welds are generated and the appearance is deteriorated and the strength becomes a problem. Moreover, since the thing with sufficient thickness is hard to damage when drilling by machining etc., the merit which applies this invention is small.

  However, in the present invention, the plate-like portion forming the through hole 3 does not necessarily have to be a flat surface, and may be bent or bent.

Further, in the above example, in the injection molding process, is to form a recess 2 on the formation planned section of the through hole 3, when the drilling performed CO ₂ laser irradiation at a later in this section, the irradiation time This is for shortening and performing hole drilling efficiently. Therefore, it is necessary to set the thinnest portion of the portion where the concave portion 2 is formed to be 0.1 to 0.8 mm, and in particular, 0.3 to 0.6 mm. It is preferable to set. That is, if the concave portion 2 is too shallow (the thickness of the portion is too thick), it takes time to irradiate the CO ₂ laser, and the production efficiency is lowered. Conversely, the concave portion 2 is too deep (the thickness of the portion is too thin). ) And the flow of the resin material around the concave portion 2 at the time of injection molding.

  And it is desirable that the shape of the recess 2 is such that the resin material flows smoothly around and around the back during injection molding. Of course, as shown in FIG. 1A, there is no problem even if the bottom surface of the recess 2 is flat. More preferably, for example, as shown in FIG. 3A, the bottom surface is conical or pyramidal. 3 (b), the bottom surface is recessed in a circular arc shape as shown in FIG. 3 (b), and the bottom surface is polygonal as shown in FIG. 3 (c). It is to set to the shape etc. which were dented.

  Furthermore, in the above example, the molded body 1 in which the through-hole 3 is formed becomes the lid 7 of the compact container in combination with the lid body 5, but the injection molded body with a hole of the present invention is not necessarily It is not necessary to use in combination with other members, and the molded body 1 itself with the through holes 3 formed therein may be used as a product. Therefore, the through hole 3 may be used for fitting with other members as in the above example, or may remain open. And the hole diameter and hole shape can also be set suitably according to the use and purpose.

  Further, the through hole 3 does not need to be formed straight in the thickness direction. For example, as shown in FIG. 4A, the through hole 3 is oblique to the thickness direction of the portion of the molded body 1 where the through hole 3 is formed. It may be formed. Conventionally, it is difficult to form the through holes 3 obliquely as in this example by shaping with a mold or punching with a punch member incorporated in the mold. When necessary for design or functional reasons, this can be obtained easily and at low cost by the production method of the present invention, and thus has great practical value.

Then, in order to form the through hole 3 in the oblique direction as described above, for example, as shown in FIG. 4B, in the injection molding process, one side is opposite to the part to be formed of the through hole 3 with an inclined surface. It is preferable to form the recess 2a having a vertical surface, and to form a recess 2b having an inclined surface that supplements the vertical surface of the recess 2a from the surface opposite to the surface on which the recess 2a is formed. If such a shape is preliminarily shaped, the portion to be removed to form the through-hole 3 becomes a thin-walled portion (indicated by a fine oblique line Q in the figure), so in the drilling step after demolding, By performing the CO ₂ laser irradiation from the oblique direction indicated by the arrow P, it is possible to open a clean through hole 3 in a short time.

Further, in the same manner as in the above example, as shown in FIG. 5, for example, in the container main body 10 of the compact container provided with the recess 11 for accommodating the inner dish filled with the cosmetic, the bottom surface of the recess 11 is provided. The through hole 3 ′ can be formed by CO ₂ laser irradiation after the injection molding of the container body 10. The through-hole 3 ′ is a recess formed by inserting an intermediate dish (not shown) attached in the recess 11 through an adhesive or the like from the back side of the container body 10 with an intermediate dish takeout tool such as a rod-shaped body. 11 is a hole for taking out the inner dish. When this through hole 3 'is formed by CO ₂ laser irradiation, the periphery of the through hole 3' and the inner peripheral surface thereof are smooth. Therefore, even if the hole diameter of the through hole 3 'is small, a rod-like body inserted through this portion. The slide is good and the inner plate can be removed smoothly. The appearance from the back side of the container body 10 is also good. The through hole 3 ′ can have an appropriate opening shape (for example, a long hole) according to the shape of the intermediate dish removing tool.

Further, as shown in FIG. 5, in the container body 10 of the compact container provided with the recess 12 for accommodating the cosmetic sponge, a plurality of through holes 3 ″ serving as vent holes are formed on the bottom surface of the recess 12. In the same manner as in the above example, it can be formed by CO ₂ laser irradiation after the injection molding of the container body 10. In this case, too, a lot of very small hole diameters can be obtained easily and beautifully, Is preferred.

Furthermore, the present invention can be used for removing gate marks in normal injection molding. That is, as shown in FIG. 6, in normal injection molding, the portion 20 where the gate mark remains is intentionally formed thin, and after demolding, in this portion 20, as in the above example, By forming the through hole by CO ₂ laser irradiation, the gate trace can be removed. In this case, a beautiful through-hole is formed in the portion where the gate mark should originally remain, and an appearance having no sense of incongruity can be obtained.

In addition, for example, in the case where a cylindrical body having a relatively large opening 30 on the top surface as shown in FIG. 7A is directly obtained by injection molding using a normal gate, the cylindrical circumferential direction is obtained. In order to form the opening 30 as shown in FIG. 7B, the resin material is difficult to flow, so that a weld is generated on the opposite side of the gate and the portion is easily broken. After performing injection molding using a fan gate having an annular recess 31, the residual strain is reduced by irradiating the annular recess 31 with a CO ₂ laser as indicated by an arrow in the same manner as in the above example. A high-quality molded body with openings 30 can be obtained. In this case, the opening 30 is the “through hole” of the present invention. According to this method, even when a hard resin is used, the remaining fan gate portion can be easily removed by CO ₂ laser irradiation to form the opening 30, so that a relatively high strength is required. Ideal for obtaining plugs and the like.

Note that the hole-injection-molded article of applying the present invention is not limited to the above example, Ru can be applied to injection molded articles for various compact container.

(A), (b) is explanatory drawing of the drilling process in one Example of this invention. It is explanatory drawing of the usage condition of the injection molded object of the said Example. (A)-(c) is explanatory drawing of the modification of the recessed part shape in the drilling process of the said Example, all. (A) is explanatory drawing of the hole shape in the other Example of this invention, (b) is explanatory drawing of the drilling process. It is explanatory drawing of other Example of this invention. It is explanatory drawing of the example of application of this invention. (A) is explanatory drawing of the further another Example of this invention, (b) is explanatory drawing of the drilling process.

Explanation of symbols

1 Molded body 2 Recessed part 3 Through hole

Claims (5)

An injection molding step of obtaining a molded body having a plate-shaped portion having a thickness of 0.5 to 5.0 mm by injection molding a resin material using a predetermined mold, and CO in the plate-shaped portion of the molded body _{2 A} drilling step of forming a through-hole by irradiating a laser, and in the injection molding step, using the mold, the through-hole formation scheduled portion of the molded product is thinnest. The portion forms a recess having a thickness of 0.1 to 0.8 mm, and in the drilling step, laser irradiation is performed toward the recess formed in the through-hole formation planned portion, thereby reducing the bottom surface of the recess. A method for producing an injection-molded body with a hole for a compact container, wherein the hole is completely removed to form a through hole. An injection-molded body with holes for a compact container obtained by the manufacturing method according to claim 1, comprising a plate-like portion having a thickness of 0.5 to 5.0 mm, and the plate-like portion is irradiated with CO ₂ laser. An injection molded body with a hole for a compact container, wherein the formed through hole is provided. The injection molded body with holes for a compact container is a container body of a compact container, and has a recess for accommodating a cosmetic sponge, and a plurality of through holes formed by CO ₂ laser irradiation are formed on the bottom of the recess. The injection molded body with holes for a compact container according to claim 2, which is provided as a vent hole. The injection molded body with a hole for a compact container is a container body of a compact container, and has a concave portion for accommodating an inner dish filled with cosmetics, and is formed on the bottom surface of the concave portion by CO ₂ laser irradiation. The injection molded body with a hole for a compact container according to claim 2 or 3, wherein the through hole is provided as a hole for inserting the intermediate dish removing tool from the back side of the container body to remove the intermediate dish in the recess. The injection molded body with a hole for a compact container according to any one of claims 2 to 4, wherein the through hole formed by the CO ₂ laser irradiation is formed obliquely with respect to the thickness direction of the molded body.

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