JPH02180137A - Cosmetic container and its manufacture method - Google Patents

Abstract

PURPOSE:To provide a cosmetic container composed of a resin only, having glossy surface, free from the exposed glass fiber and air bubbles by using the metal dies employed in the molding of the container with their shaping surfaces preheated to a temperature higher than the deformation-causing temperature of thermoplastic resins. CONSTITUTION:A high-frequency oscillator 5 produces high-frequency current to generate eddy current on the shaping surfaces of metal dies in order to heat the same. The oscillator 5 of 50 - 70KW is employed which is capable of heating the shaping surfaces preheated to 60 - 80 deg.C by a heater to 100 - 130 deg.C with the oscillation time set at 5 - 10sec. After heating the shaping surfaces at least to 100 deg.C in this way, a cylinder 4 is actuated to remove a heater coil 3 from between metal dies 1 and 2 and, at the same time, the dies are closed. The thermoplastic resins (containing glass fiber or air bubbles due to foaming agent) heated at 180 - 260 deg.C into a molten state is injected into the dies from an injection device 6 and allowed to stand for predetermined hours for cooling. The dies are thereafter opened to take out the molded container.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a cosmetic container having a glossy appearance and a method for manufacturing the same.

[Prior Art] Recently, thermoplastic resin molded products have been widely used as cosmetic containers such as compacts, milky lotions, and cream containers. Such a resin cosmetic container is usually obtained by injection molding each container component (for example, the main body 2M, the inner lid, etc.) and then integrally combining them. In the above injection molding, first the resin material is
It is heated to about 80 to 260°C to make it fluid, and in this state it is injected into a predetermined mold. Then, after the whole is cooled and the resin is solidified within the mold, the mold is opened and the molded product is taken out. Therefore, the purpose of the mold is to cool the resin material, and the temperature is usually adjusted to about 60 to 70°C so as not to exceed the heating deformation temperature of the thermoplastic resin.

[Problem that the invention seeks to solve]

By the way, such cosmetic containers are not only required to have chemical resistance and fragrance retention, but also to be lightweight.
The important points are that it has excellent mechanical strength and is highly decorative.

For example, for a portable compact, it is desirable to have thin walls, be lightweight, and be difficult to break.However, if the wall thickness is made too thin, the mechanical strength of a simple thermoplastic phase molded product will be insufficient. , the overall result is a thick container. Therefore, in order to supplement the rigidity of the resin, it has been proposed to add glass fiber to the resin. However, when glass fiber is added, the mold temperature is low on the surface that comes into contact with the mold during molding (i.e., the surface of the molded product), so the fluidity of the resin that approaches the mold decreases rapidly, causing the resin to mix with the glass fibers. A situation occurs in which the fluid does not flow sufficiently between the fibers. Therefore, the glass fibers are exposed on the surface of the resulting molded product, resulting in a rough surface and a glossy and beautiful appearance cannot be obtained. In addition, cream containers and the like are desired to have a rich volume and are elaborately decorated, and foaming agents are added to thermoplastic resin to foam the resin and then molded. In this case, similarly to the above, the fluidity of the resin deteriorates around the mold surface and bubbles due to foaming are exposed on the surface of the molded product, making it impossible to obtain a glossy and beautiful appearance. As described above, the reality is that a glossy and aesthetically pleasing container has not been obtained as a container that has excellent rigidity or a container that has volume through foaming.

The present invention was made in view of the above circumstances, and provides a cosmetic container that is made of glass fiber for increased rigidity or foamed with a foaming agent, and that has a glossy surface and is aesthetically pleasing. The purpose is to provide the manufacturing method.

[Means for solving problems]

To achieve the above object, the present invention provides a cosmetic container made of a thermoplastic resin containing dispersed fillers such as glass fibers or blowing agents, wherein the surface layer of the container is filled with glass fibers or blowing agents. The first gist is a cosmetic container that is formed of a thermoplastic resin layer that does not contain any additives and whose surface is made glossy by contact heating, and the thermoplastic resin containing fillers such as glass fiber or foaming agents is heated. A method for manufacturing a cosmetic container in which the cosmetic container is introduced into a mold in a fluidized state, cooled, and shaped into a predetermined shape, the shaping surface of the mold being heated in advance to a temperature higher than the heating deformation temperature of the thermoplastic resin. The second gist is a method for manufacturing cosmetic containers using a material.

(Function) That is, the present invention uses a mold used for molding a cosmetic container, the molding surface of which has been previously heated to a temperature higher than the heating deformation temperature of the thermoplastic resin. The thermoplastic resin that has come into contact with the mold forming surface further increases its fluidity and flows sufficiently between glass fibers or between air bubbles generated by the blowing agent, and as a result, the mold forming surface is improved. A thin resin film is formed inside the shaped surface, and the surface of the resulting molded product has a glossy surface made only of resin without exposing glass fibers or air bubbles.

Next, the present invention will be explained in detail.

First, the object of the present invention is a cosmetic container made of a thermoplastic resin containing glass fiber or air bubbles dispersed therein. Examples of such containers include compacts, portable pallets, etc., which need to be reinforced with glass fibers and molded into a thin shape, and cream containers, which are made voluminous by foaming bubbles.

The thermoplastic resin used for the container is not particularly limited, and polystyrene, styrene-acrylonitrile copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), and polyethylene, which are commonly used as container forming materials, can be used.

Examples include polypropylene.

As the glass fiber contained in the thermoplastic resin, it is preferable to use one having a length of about 0.3 to 6 m. However, the glass fiber has a 5% content with respect to the thermoplastic resin.
In order to increase the rigidity of the resin, it is preferable to contain the glass in a range of 60% by weight (hereinafter abbreviated as "%"). In addition to the fibers, additives such as talc, potassium titanate, calcium aluminum carbonate powder, and various pigments can be appropriately blended.

In addition, the foaming agent contained in the thermoplastic resin is used to cause foaming within the resin by reaction with an auxiliary agent or by heating at the stage where the resin is heated to give fluidity, and examples include azodicarbonamide. . These blowing agents may be used alone or in combination of two or more. The amount used depends on how much volume the resin molded product has, but it is usually 0.1% of the thermoplastic resin.
It is suitable to use within the range of ~5%.

The cosmetic container of the present invention can be manufactured using the above raw materials, for example, in the following manner. In other words, first
Prepare a molding device as shown in the figure. 1.2 is a set of upper and lower molds capable of forming the shape of the intended cosmetic container, and is incorporated into a normal injection molding machine. 3 is 6m in diameter
The heat coil is made of a copper pipe with a diameter of about 1.5 m, and is processed from above when the mold is opened before molding, and is placed at an intermediate position between the molds 1 and 2. 4 is the above heat coil 3
It is a cylinder that moves up and down. 5 is a high frequency oscillation device for generating a high frequency magnetic field in the heating coil. In the above arrangement, a high frequency current is oscillated from the high frequency oscillator 5 to generate a magnetic field in the heating coil 3, thereby generating an eddy current on the mold forming surface to heat the mold forming surface. By the way, the output of the high frequency oscillator 5 is 50~
By using a 70KW and setting the oscillation time to 5 to 10 seconds, the forming surface of the mold, which was previously heated to 60 to 80 °C by the temperature controller, can be heated to 100 to 130 °C. can. After the mold forming surface is heated to 100° C. or higher by high-frequency induction heating in this manner, the cylinder 4 is activated to take out the heating coil 3 upwardly from between the molds 1 and 2, and simultaneously close the mold.

Then, the thermoplastic resin (containing air bubbles caused by glass fiber or foaming agent) that has been heated to 180 to 260"C and is in a fluid state is injected into the mold from the injection device 6, and is left to cool for a predetermined period of time. After that, the mold is opened and the molded product is taken out.

When the molded product thus obtained contains glass fibers, the surface is formed only of the thermoplastic resin 10 and the glass fibers 11 are not exposed, as shown in FIG. It has a glossy surface. Furthermore, even in the case where a foaming agent is pre-contained in a thermoplastic resin and bubbles are dispersed and generated within the resin by heating, the surface is formed only by the thermoplastic resin 10, as shown in FIG. Since the bubbles 12 are not exposed, it has a smooth glossy surface.

In this way, the cosmetic container obtained by this molding method has a molding surface that looks as if a thin, uniform resin film has been formed along the molding surface, so even if it contains glass fibers or air bubbles, , appearance defects such as weld lines and silver streaks do not occur. Therefore, there is no need to further apply a coating treatment to the surface of the container, and the container has a beautiful appearance as it is.

In addition, if a fine uneven pattern such as grain processing or hairline processing is applied to the mold forming surface in advance, this uneven pattern will be directly transferred to the resin film part, so that it can be applied to the surface of the cosmetic container according to the purpose. It has the advantage of being able to create finely textured textures and expanding the range of designs.

In the above manufacturing method, the shaping surfaces of the molds 1 and 2 may be heated not by high-frequency induction heating but by infrared heating by irradiation from a halogen lamp or the like.

Also, before heating the shaping surface, heat this surface to 500 to 520
It has been found that if the mold is nitrided and colored black at a temperature of about °C, the heating efficiency improves and the time required to raise the temperature of the mold forming surface to the desired temperature can be shortened.

Next, examples will be described together with comparative examples.

[Example 1] A compact main body 15 having the shape shown in FIG. 116 was molded according to the manufacturing method described above. In addition, the heating temperature of the mold shaping surface by high frequency induction heating was 100-170 degreeC.

The surface of the thus obtained molded product had no exposed glass fibers and had a very glossy surface. In this molded product, both the main body 15 and 116 have a wall thickness of 0.6~
At 0.8 mm, it is much thinner than conventional resin containers, but because it contains glass fiber, it has excellent impact resistance and can withstand practical use.

[Comparative Example 1] Using the same material as in Example 1 above, a compact having the same shape as above was molded using a normal mold that does not perform high-frequency induction heating. The surface of the obtained molded article was a rough surface with poor gloss due to exposed glass fibers.

[Comparative Example 2] A compact having the same shape as above was molded in the same manner as Comparative Example 1 using ABS resin that does not contain glass fiber. Although the surface of the obtained molded product was glossy, it had poor impact resistance due to its thin wall thickness, making it unsuitable for practical use.

[Application example]

A compact having the same shape as in Example 1 was molded in the same manner as in Example 1 using ABS resin containing 0.5% of Burl pigment and 1.0% of aluminum powder. However, the heating temperature of the mold shaping surface by high-frequency induction heating is 100 to 1
The temperature was 20°C.

The molded surface thus obtained had a shiny metallic appearance.

[Comparative Example 3] Using the same material as in the above application example, a compact having the same shape as above was molded by a normal method. The surface of the obtained molded product was glossy (and had almost no metallic feel).

[Example 2] Using ABS resin containing 0.1% of a foaming agent (Celmark GE, manufactured by Sankyo Kasei Co., Ltd.), the main body 17 and cap 8 of a cream container having the shape shown in FIG. It was molded in the same manner. However, the heating temperature of the mold shaping surface by high-frequency induction heating was 100 to 120°C.

The surface of the molded article thus obtained had no exposed air bubbles and had a glossy surface as if it were made only of resin.

[Comparative Example 4] Using the same materials as in Example 2 above, a cream container having the same shape as above was molded in a conventional manner. The surface of the obtained molded product had exposed air bubbles and fine irregularities, and was not aesthetically pleasing.

[Example 3] A compact having the same shape as in Example 1 was molded using the same material as in Example 1 above. At this time, the mold forming surface is
Irradiate with an infrared lamp for 15 seconds and heat to 100-120'C.
heated to.

The molded article obtained in this way was good as in Example 1.

(Example 4) A compact having the same shape as in Example 1 was molded using the same material as in Example 1 above. At this time, the mold forming surface is
Prior to heating, the material was nitrided at 500 to 520°C and colored black. This mold forming surface is heated by high frequency induction heating.
．． Heating from OO to 120'C took 3-7 seconds. Furthermore, it took 10 seconds to heat the sample to the above temperature using an infrared lamp. The required heating time was about 2/3 of that without nitriding.

The molded article obtained in this way was good as in Example 1.

〔Effect of the invention〕

As described above, according to the present invention, even if a cosmetic container is molded using a thermoplastic resin containing glass fibers, a blowing agent, etc. dispersed therein, no glass fibers or air bubbles are exposed on the surface, and it is as if only the resin is used. You can get a shiny and beautiful surface that looks like it was molded with. Therefore, it is possible to obtain containers that have unprecedented beauty, such as thin compacts that have sufficient strength due to glass fibers and foam containers that are voluminous and smooth.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a configuration diagram showing the main parts of a molding apparatus used for carrying out the present invention, FIG. 2 is a schematic sectional view showing a glass fiber-containing molded product obtained by the present invention, and FIG. FIG. 3 is a schematic cross-sectional view showing a bubble-containing molded article obtained according to the present invention, FIG. 4 is a longitudinal cross-sectional view showing the shape of a cosmetic container obtained according to an embodiment of the present invention, and FIG. FIG. 7 is a longitudinal cross-sectional view showing the shape of a cosmetic container obtained in another example. 1.2... Mold 3... Heat coil 5... High frequency oscillator 10... Thermoplastic resin 11... Glass fiber 12-- Cell patent applicant Kii Sangyo Co., Ltd. agent Patent attorney Nishi Yukihiko Embryo

Claims (2)

[Claims] (1) A cosmetic container made of a thermoplastic resin containing dispersed fillers such as glass fibers or blowing agents, wherein the surface layer of the container is a thermoplastic resin layer that does not contain fillers such as glass fibers or blowing agents. A cosmetic container characterized in that the surface thereof is formed into a glossy surface by contact heating. (2) A method for manufacturing cosmetic containers in which a thermoplastic resin containing a filler such as glass fiber or a foaming agent is introduced into a mold in a heated and fluidized state, cooled, and shaped into a predetermined shape, which is used as a mold. A method for producing a cosmetic container, characterized in that the shaped surface thereof is heated in advance to a temperature higher than the heat deformation temperature of the thermoplastic resin.