JP2008194910A - Resin molding apparatus and resin molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin molding apparatus capable of selectively heating a thermoplastic resin in the cavity in comparison with a rubber-made molding die and restraining the deformation of the molding die and to provide a resin molding method. <P>SOLUTION: The resin molding apparatus 1 has the rubber-made molding die 2, the electromagnetic wave generating means 4 that emits the electromagnetic wave having wavelengths of 0.78-4 μm, the glass-made filter 52 for reducing the penetration amount of the electromagnetic wave that exceeds 2 μm in wavelength and the rubber-made filter 51 that absorbs the electromagnetic wave of the wavelength region absorbed in the molding die 2 out of the electromagnetic wave that penetrates the glass-made filter 52. In packing the molten thermoplastic resin 3 into the cavity 21 the resin molding apparatus 1 allows the electromagnetic wave emitted from the electromagnetic wave generating means 4 to penetrate the glass-made filter 52 and the rubber-made filter 51, irradiates the penetrating electromagnetic wave, which has been allowed to penetrate the glass-made filter 52 and the rubber-made filter 51, onto the thermoplastic resin 3 through the molding die 2, and heats the thermoplastic resin 3 to a temperature higher than that of the molding die 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin molding apparatus and a resin molding method for obtaining a resin molded product from a thermoplastic resin.

Thermoplastic resins are molded by various molding methods and used after being formed into molded products. Various molding methods such as injection molding, blow molding, extrusion molding, and press molding have been put into practical use in accordance with the crystallinity, amorphousness, or melt viscosity level, and further in accordance with the shape of the molded product.
By the way, depending on the type of the thermoplastic resin and the shape of the molded product, the temperature of the thermoplastic resin is lowered during molding, so that the melt viscosity becomes high, and it may be difficult to obtain the intended molded product. Therefore, in order to improve this, a method of heating a molding die (mold) for molding a molded product with a heater or the like is known.

  Further, for example, in the resin molding method of Patent Document 1, a molten thermoplastic resin is injected into a cavity of a molding die made of silicone rubber, and then the thermoplastic resin is cooled to obtain an injection molded product. Is disclosed. Then, the composition of the silicone rubber mold is devised for the purpose of easily producing a resin molded product having good surface accuracy and surface gloss.

However, in the conventional resin molding method described above, the temperature of the thermoplastic resin to be molded may decrease and the viscosity of the thermoplastic resin may increase, particularly at the end of the cavity filled with the thermoplastic resin. In this case, there is a risk of poor filling of the thermoplastic resin in the cavity of the mold.
In Patent Document 1, the heat resistant temperature of silicone rubber is, for example, about 200 ° C. If the heating temperature of a heater or the like is increased in order to prevent the temperature of the resin from being lowered, the silicone rubber mold is deteriorated. There is a possibility that the surface appearance of the molded product molded by the molding die is lowered.

  Further, for example, in the method and apparatus for producing a resin molded article of Patent Document 2, when obtaining a molded product by introducing granular or powdery metal aggregate and thermoplastic resin into a mold, a metal aggregate is used. A metal heating means that can be heated in a spot manner is used. In this manufacturing method, the metal aggregate in the mold is irradiated with microwaves or electromagnetic waves from the metal heating means to generate heat, and the heat generated from the metal aggregate is used to generate heat in the mold. After the thermoplastic resin is softened or dissolved, the resin molded product is pressure-molded.

  However, the technique of Patent Document 2 is a technique that selectively heats the metal aggregate, and is not a technique that can heat the thermoplastic resin itself. Further, when the metal aggregate is heated by the metal heating means, the mold is also heated at the same time. Therefore, it is not possible to selectively heat the thermoplastic resin without heating the formwork too much.

JP-A-7-178754 Japanese Patent Laid-Open No. 10-193370

  The present invention has been made in view of such conventional problems, and can selectively heat the thermoplastic resin in the cavity with respect to the rubber mold, thereby suppressing deformation of the mold. An object of the present invention is to provide a resin molding apparatus and a resin molding method that can be used.

According to a first aspect of the present invention, there is provided a rubber mold having a cavity for filling a thermoplastic resin,
An electromagnetic wave generating means for emitting an electromagnetic wave having a wavelength of 0.78 to 2 μm;
Between the electromagnetic wave generating means and the mold, a predetermined gap is formed with respect to the mold, and the wavelength region of the electromagnetic waves emitted from the electromagnetic wave generating means is absorbed by the mold. And having a rubber filter that absorbs at least the peak electromagnetic wave in the wavelength region,
When the thermoplastic resin is filled in the cavity, the electromagnetic wave emitted from the electromagnetic wave generating means is transmitted through the rubber filter, and the transmitted electromagnetic wave after passing through the rubber filter is converted into the molding. The resin molding apparatus is configured to irradiate the thermoplastic resin through a mold (claim 1).

  The resin molding apparatus of the present invention is an apparatus for molding a resin molded product made of a thermoplastic resin using a rubber mold, and can selectively heat the thermoplastic resin to the mold. Device. That is, the resin molding apparatus of the present invention includes a rubber mold, an electromagnetic wave generating unit that emits an electromagnetic wave having a wavelength of 0.78 to 2 μm, and a mold among the electromagnetic waves emitted from the electromagnetic wave generating unit. And a rubber filter that absorbs at least a peak electromagnetic wave in the wavelength region to be absorbed.

When the thermoplastic resin is filled into the cavity of the rubber mold, an electromagnetic wave having a wavelength of 0.78 to 2 μm is emitted from the electromagnetic wave generating means and transmitted through the rubber filter. The thermoplastic resin is irradiated through a mold. At this time, due to the difference in physical properties between the rubber and the thermoplastic resin constituting the mold, the thermoplastic resin can be greatly heated as compared with the rubber mold. Thereby, the temperature of the thermoplastic resin in the cavity can be maintained higher than the temperature of the mold until the filling of the thermoplastic resin into the cavity is completed.
Therefore, it is possible to prevent poor filling of the thermoplastic resin in the cavity and obtain a good resin molded product.

  By the way, the electromagnetic wave having a wavelength of 0.78 to 2 μm emitted from the electromagnetic wave generating means includes an electromagnetic wave in a wavelength region that is absorbed by the rubber constituting the mold. And, if an electromagnetic wave having a wavelength of 0.78 to 2 μm is directly irradiated on the mold, the electromagnetic wave is absorbed from the surface side in the mold, so that the electromagnetic wave is compared with the inner side forming the cavity. The surface side that is directly irradiated is heated more, and the temperature on the surface side becomes higher than the inner side. Thereby, there exists a possibility that a shaping | molding die may deform | transform.

  On the other hand, in the present invention, the rubber filter is disposed between the electromagnetic wave generating means and the mold so as to form a predetermined gap with respect to the mold. Of the electromagnetic waves emitted from the electromagnetic wave generating means, the electromagnetic wave having a wavelength region that is absorbed by the rubber constituting the mold and at least the peak of this wavelength region can be absorbed by the rubber filter.

  Thereby, in this invention, while the rubber filter is heated, the ratio by which a shaping | molding die is heated can be decreased. In addition, since there is a predetermined gap between the rubber filter and the mold, heat generated in the rubber filter is transferred to the surface side of the mold (the side to which the transmitted electromagnetic wave is irradiated). Can be suppressed.

And while the temperature rise on the surface side of a shaping | molding die can be suppressed, the temperature difference of the surface side of a shaping | molding die and an internal side (side which forms a cavity) can be made small.
Therefore, it can suppress that a shaping | molding deform | transforms, and it can suppress that the dimensional accuracy of the resin molded product to shape | mold falls with this deformation | transformation. In addition, the durability of the mold can be improved.

  Therefore, according to the resin molding apparatus of the present invention, the thermoplastic resin in the cavity can be selectively heated with respect to the rubber mold, and the durability of the mold can be improved.

The reason why the thermoplastic resin can be selectively heated by the transmitted electromagnetic wave as compared to the rubber mold is considered as follows.
That is, it is considered that the transmitted electromagnetic wave irradiated on the surface of the rubber mold has a high ratio of being reflected by the surface of the mold or being transmitted through the mold, whereas it is absorbed by the thermoplastic resin. Therefore, it is considered that the energy of light by the transmitted electromagnetic wave is preferentially absorbed by the thermoplastic resin, and the thermoplastic resin can be selectively heated.

According to a second aspect of the present invention, there is provided a rubber mold that forms a cavity for filling a thermoplastic resin,
An electromagnetic wave generating means for emitting an electromagnetic wave having a wavelength of 0.78 to 4 μm;
A glass filter which is disposed between the electromagnetic wave generating means and the mold and reduces the amount of electromagnetic waves having a wavelength exceeding 2 μm;
Between the glass filter and the mold, a predetermined gap is formed with respect to the mold, and the electromagnetic wave transmitted through the glass filter has a wavelength region that is absorbed by the mold. And having a rubber filter that absorbs at least the peak electromagnetic wave in the wavelength region,
When filling the cavity with the thermoplastic resin, the electromagnetic wave emitted from the electromagnetic wave generating means is transmitted through the glass filter and the rubber filter, and is transmitted through the glass filter and the rubber filter. The resin molding apparatus is configured to irradiate the thermoplastic resin through the molding die after being transmitted (claim 2).

  The resin molding apparatus of the present invention is also an apparatus that can selectively heat a thermoplastic resin with respect to a mold. In addition to the rubber mold, the electromagnetic wave generating means, and the rubber filter, the resin molding apparatus of the present invention has a glass filter that reduces the amount of electromagnetic waves transmitted with the wavelength exceeding 2 μm. Yes.

Also in the present invention, as in the first aspect of the invention, the thermoplastic resin can be greatly heated compared to the rubber mold, and a good resin molded product can be obtained.
Also in the present invention, by using the rubber filter, as in the first invention, the temperature difference between the surface side and the inner side of the mold can be reduced, and the durability of the mold can be improved. Can be improved.

  Furthermore, in the present invention, the thermoplastic resin can be effectively heated by disposing the glass filter between the electromagnetic wave generating means and the mold. That is, the electromagnetic wave emitted from the electromagnetic wave generating means includes an electromagnetic wave having a wavelength exceeding 2 μm, but by using a glass filter, the electromagnetic wave having a wavelength exceeding 2 μm is not irradiated to the mold as much as possible. Can be. As a result, the thermoplastic resin filled in the cavity of the mold can be effectively irradiated with an electromagnetic wave having a wavelength of 2 μm or less. Therefore, the thermoplastic resin can be effectively heated by an electromagnetic wave having a wavelength of 2 μm or less without heating the mold very much.

  And in this invention, the electromagnetic wave after permeate | transmitting a glass filter is irradiated to a rubber filter. Thereby, it is possible to prevent the electromagnetic wave having a wavelength exceeding 2 μm from being irradiated to the rubber filter as much as possible, and to reduce the heating amount of the rubber filter. Therefore, the durability of the rubber filter can be improved.

Therefore, according to the resin molding apparatus of the present invention, the thermoplastic resin in the cavity can be selectively heated with respect to the rubber mold, and the durability of the mold and the rubber filter can be improved. Can do.
The reason why the thermoplastic resin can be selectively heated by the transmitted electromagnetic wave as compared with the rubber mold is considered as in the first invention.

A third invention is a resin molding method for obtaining a resin molded product by filling a thermoplastic resin into a cavity of a rubber mold and cooling the thermoplastic resin,
When the thermoplastic resin is filled in the cavity, an electromagnetic wave generating means for emitting an electromagnetic wave having a wavelength of 0.78 to 2 μm, and between the electromagnetic wave generating means and the mold, with respect to the mold A rubber filter that is arranged to form a predetermined gap and that absorbs at least the peak electromagnetic wave in the wavelength region of the electromagnetic wave emitted from the electromagnetic wave generating means and absorbed by the mold. Use
The electromagnetic wave emitted from the electromagnetic wave generating means is transmitted through the rubber filter, and the electromagnetic wave transmitted through the rubber filter is irradiated onto the thermoplastic resin through the molding die to thereby generate the heat. A resin molding method is characterized in that the plastic resin is heated.

According to the resin molding method of the present invention, by molding a resin molded product using the rubber mold, the electromagnetic wave generating means, and the rubber filter, a good resin is obtained as in the first invention. A molded product can be obtained.
Also in the resin molding method of the present invention, by using the rubber filter, as in the first invention, the temperature difference between the surface side and the inner side of the molding die can be reduced. The durability of can be improved. Moreover, according to the resin molding method of the present invention, a resin molded product having excellent dimensional accuracy can be obtained.

Therefore, according to the resin molding method of the present invention, the thermoplastic resin in the cavity can be selectively heated with respect to the rubber mold, and the durability of the mold can be improved.
The reason why the thermoplastic resin can be selectively heated by the transmitted electromagnetic wave as compared with the rubber mold is considered as in the first invention.

A fourth invention is a resin molding method in which a thermoplastic resin is filled in a cavity of a rubber mold, and the thermoplastic resin is cooled to obtain a resin molded product,
When the thermoplastic resin is filled in the cavity, an electromagnetic wave generating means for emitting an electromagnetic wave having a wavelength of 0.78 to 4 μm is disposed between the electromagnetic wave generating means and the mold, and the wavelength is set to 2 μm. A glass filter that reduces the amount of transmission of electromagnetic waves exceeding, and an electromagnetic wave that is disposed between the glass filter and the mold so as to form a predetermined gap with respect to the mold and is transmitted through the glass filter. Among them, using a rubber filter that absorbs electromagnetic waves at least in the wavelength region of the wavelength region that is absorbed by the mold,
The electromagnetic wave emitted from the electromagnetic wave generating means is transmitted through the glass filter and the rubber filter, and the transmitted electromagnetic wave after passing through the glass filter and the rubber filter is transmitted through the mold. The resin molding method is characterized by heating the thermoplastic resin by irradiating the thermoplastic resin.

According to the resin molding method of the present invention, a resin molded product is molded by using the rubber mold, the electromagnetic wave generating means, the glass filter, and the rubber filter, and the same as in the first invention. In addition, a good resin molded product can be obtained.
Also in the resin molding method of the present invention, by using the rubber filter, as in the first invention, the temperature difference between the surface side and the inner side of the molding die can be reduced. The durability of can be improved. Also, a resin molded product having excellent dimensional accuracy can be obtained by the resin molding method of the present invention.
Furthermore, in the resin molding method of the present invention, the durability of the rubber filter can be improved by using the glass filter, as in the second invention.

Therefore, according to the resin molding method of the present invention, the thermoplastic resin in the cavity can be selectively heated with respect to the rubber mold, and the durability of the mold and the rubber filter can be improved. Can do.
The reason why the thermoplastic resin can be selectively heated by the transmitted electromagnetic wave as compared with the rubber mold is considered as in the first invention.

A preferred embodiment in the first to fourth inventions described above will be described.
In the first to fourth inventions, the transmitted electromagnetic wave irradiated to the thermoplastic resin through the molding die includes not only an electromagnetic wave having a wavelength of 0.78 to 2 μm but also an electromagnetic wave of other area. It may be. In this case, it is preferable that the transmitted electromagnetic wave irradiated to the thermoplastic resin through the mold includes more electromagnetic waves in the region having a wavelength of 0.78 to 2 μm than electromagnetic waves in the entire other region.

The reason why the electromagnetic wave having a wavelength of 0.78 to 2 μm is used for heating the thermoplastic resin is that the electromagnetic wave having a wavelength of this wavelength is easily transmitted through a rubber mold. This is because the resin is easily absorbed.
Further, not only one electromagnetic wave generating means but also a plurality of electromagnetic wave generating means can be used. The mold can be irradiated with the transmitted electromagnetic wave not only from one direction but also from multiple directions.

In the second and fourth inventions, the glass filter is preferably made of quartz glass that reduces the transmission of electromagnetic waves having a wavelength exceeding 2 μm.
The glass filter may be made of a material other than quartz glass as long as it has a property of reducing the amount of transmission of electromagnetic waves having a wavelength exceeding 2 μm. For example, as a glass filter, in addition to quartz glass, porous glass (for example, Vycor (registered trademark) glass), silicoborate glass (for example, Pyrex (registered trademark) glass), and the like are used. Can be used.

In the first to fourth inventions, it is preferable that the rubber filter is made of the same material as that of the mold (claims 4 and 11).
In this case, the absorbance of the rubber filter (a measure indicating the absorption intensity with respect to light (electromagnetic waves) of a specific wavelength) can be matched with the absorbance of the rubber mold. Thereby, most of the electromagnetic waves in the wavelength region absorbed by the rubber constituting the mold among the electromagnetic waves emitted from the electromagnetic wave generating means can be absorbed by the rubber filter. Therefore, the durability of the mold can be further improved.
Note that the material of the rubber filter and the mold may not necessarily match completely as long as the light absorption characteristics such as absorbance are similar (for example, even if there is a slight difference in composition, structure, etc.). Good.

The mold and the rubber filter are preferably made of silicone rubber.
In this case, it is easy to produce the mold and the rubber filter, and the thermoplastic resin can be selectively heated by the transmitted electromagnetic wave with little heating of the mold.
Moreover, it is preferable that the hardness of a silicone rubber is 25-80 in a JIS-A standard measurement.

The mold is placed in a pressure vessel that can be depressurized and increased, and the pressure vessel is provided with a vacuum pump that evacuates the pressure vessel. Before the injection of the thermoplastic resin, it is preferable that the pressure is reduced to a vacuum state by the vacuum pump, and after the injection, the pressure is increased to a pressure state higher than the atmospheric pressure (Claims 6 and 13).
In this case, after injecting the molten thermoplastic resin into the vacuum cavity, the pressure inside the pressure vessel is increased so that the thermoplastic resin injected into the cavity is spread over the entire narrow gap in the cavity. Can be fully distributed.
Note that the vacuum state does not mean only an absolute vacuum state, but a vacuum state including a reduced pressure state as long as a thermoplastic resin can be filled.

  In the first to fourth inventions, when the molding die is disposed in the pressure vessel, the electromagnetic wave generating means may be disposed either inside the pressure vessel or outside the pressure vessel. In particular, the electromagnetic wave generating means is preferably arranged outside the pressure vessel. In this case, the generated electromagnetic wave generating means can be efficiently cooled.

  In the first to fourth inventions, when the electromagnetic wave generating means is disposed outside the pressure vessel, the rubber filter is disposed in the pressure vessel, while the glass filter is disposed in the pressure vessel or It may be arranged outside the pressure vessel. Moreover, the glass filter can be provided as a wall constituting the pressure vessel. In particular, in this case, the glass filter can be provided as a window for allowing electromagnetic waves to enter the pressure vessel.

The electromagnetic wave generating means preferably emits an electromagnetic wave having an intensity peak in a wavelength region of 0.78 to 2 μm (claims 7 and 14).
In this case, a halogen heater, an infrared lamp, or the like having a predetermined distribution characteristic for the wavelength of the emitted electromagnetic wave can be used as the electromagnetic wave generating means.

Further, when the thermoplastic resin is heated by the electromagnetic wave generating means, it is preferable to heat the thermoplastic resin to a temperature higher than that of the mold.
In this case, it is possible to more effectively prevent the filling failure of the thermoplastic resin in the cavity.

Moreover, it is preferable to prevent the viscosity of the thermoplastic resin from becoming 5000 poise or higher by heating the thermoplastic resin.
In this case, an increase in the melt viscosity of the thermoplastic resin can be suppressed, and it is possible to more easily prevent the filling failure of the thermoplastic resin in the mold cavity.

In addition, when the relationship between the melt viscosity of the thermoplastic resin and the temperature is known in advance, the temperature of the thermoplastic resin becomes a temperature at which the melt viscosity becomes 5000 poise or more by irradiating the mold with a transmitted electromagnetic wave. Therefore, it is possible to fill the cavity with the thermoplastic resin.
In addition, when the viscosity of the molten thermoplastic resin in the cavity becomes 5000 poise or more, poor filling of the thermoplastic resin in the cavity may occur.

  The viscosity of the molten thermoplastic resin in the cavity is preferably as small as possible. That is, it is more preferable to prevent the thermoplastic resin from having a viscosity of 1000 poise or more by irradiating the mold with transmitted electromagnetic waves, and it is particularly preferable to prevent the viscosity of the thermoplastic resin from being 500 poise or more.

The thermoplastic resin is preferably an amorphous thermoplastic resin.
By the way, in the said 1st-4th invention, the cooling rate of a thermoplastic resin is often made comparatively slow. Therefore, the crystallinity of the thermoplastic resin may increase during cooling, which may reduce the dimensional accuracy of the resin molded product or the impact resistance of the resin molded product. On the other hand, by making the thermoplastic resin an amorphous thermoplastic resin, it is possible to prevent a decrease in dimensional accuracy and a decrease in impact resistance of the resin molded product.

  Examples of amorphous thermoplastic resins include styrene resins such as styrene / acrylonitrile copolymers, styrene / maleic anhydride copolymers, styrene / methyl methacrylate copolymers, and ABS resins (acrylonitrile / butadiene / styrene resins). ), AES resin (acrylonitrile / ethylene-propylene-diene / styrene resin), ASA resin (acrylate / styrene / acrylonitrile resin), or other rubber-modified thermoplastic resin, or polymethyl methacrylate, polycarbonate resin (PC), PC / rubber A modified thermoplastic resin alloy or the like can be used. Among these, it is particularly preferable to use a rubber-modified thermoplastic resin, and it is more preferable to use an ABS resin.

The thermoplastic resin is preferably a rubber-modified thermoplastic resin.
The rubber-modified thermoplastic resin is not particularly limited, but is preferably one containing one or more polymers obtained by graft polymerization of vinyl monomers in the presence of a rubbery polymer.
The rubbery polymer is not particularly limited, but polybutadiene, butadiene / styrene copolymer, butadiene / acrylonitrile copolymer, ethylene / propylene copolymer, ethylene / propylene / non-conjugated diene copolymer, ethylene / butene. -1 copolymer, ethylene / butene-1 / non-conjugated diene copolymer, acrylic rubber, silicone rubber and the like. These may be used alone or in combination of two or more.

  As the rubber polymer, polybutadiene, butadiene / styrene copolymer, ethylene / propylene copolymer, ethylene / propylene / nonconjugated diene copolymer, acrylic rubber is preferably used, and the rubber-modified thermoplastic is used. As the resin, for example, ABS resin, AES resin, ASA resin or the like can be used. Among these, it is more preferable to use an ABS resin.

Hereinafter, embodiments of the resin molding apparatus and the resin molding method of the present invention will be described with reference to the drawings.
(Example 1)
As shown in FIG. 1, the resin molding apparatus 1 of this example fills a molten thermoplastic resin 3 into a cavity 21 of a rubber mold 2 and cools the thermoplastic resin 3 to obtain a resin molded product. It is a device to obtain. The resin molding apparatus 1 includes a rubber mold 2 formed with a cavity 21 for filling a thermoplastic resin 3, an electromagnetic wave generating means 4 for emitting an electromagnetic wave having a wavelength of 0.78 to 4 μm, and a wavelength. A glass filter 52 that reduces the amount of electromagnetic waves that exceed 2 μm, and a rubber that absorbs electromagnetic waves having a wavelength region that is absorbed by the mold 2 and that is at least a peak in the wavelength region, among electromagnetic waves transmitted through the glass filter 52. The filter 51 is made.

Further, as shown in the figure, the glass filter 52 is disposed between the electromagnetic wave generating means 4 and the mold 2, and the rubber filter 51 is disposed between the glass filter 52 and the mold 2. A predetermined gap 210 is formed with respect to the mold 2.
When the resin molding apparatus 1 fills the cavity 21 with the molten thermoplastic resin 3, the electromagnetic wave emitted from the electromagnetic wave generating means 4 is transmitted through the glass filter 52 and the rubber filter 51, and the glass The transmission electromagnetic wave after passing through the filter 52 and the rubber filter 51 is irradiated to the thermoplastic resin 3 through the mold 2. According to the resin molding apparatus 1, the thermoplastic resin 3 can be heated to a temperature higher than that of the mold 2.

Hereinafter, the resin molding apparatus and resin molding method of this example will be described in detail with reference to FIGS.
In this example, an ABS resin (acrylonitrile butadiene styrene resin) which is an amorphous thermoplastic resin and a rubber-modified thermoplastic resin is used as the thermoplastic resin 3. The mold 2 of this example is made of silicone rubber, and the hardness of the silicone rubber is set to 25 to 80 in the JIS-A standard measurement. Silicone rubber has a property of transmitting most of near infrared rays, which are electromagnetic waves having a wavelength of 0.78 to 2 μm, and is suitable as the mold 2.
Further, the mold 2 is obtained by placing a master model (handmade actual product) of a resin molded product to be molded in a liquid silicone rubber, curing the silicone rubber, and taking out the master model from the cured silicone rubber. Can be produced.

  In addition, the absorbance for electromagnetic waves (light) having a wavelength of 0.78 to 2 μm (a measure indicating the absorption intensity with respect to light of a specific wavelength) is the ABS resin used as the thermoplastic resin 3 as the rubber mold 2. It is larger than the silicone rubber used. The absorbance can be measured using, for example, Shimadzu UV3100.

As shown in FIG. 1, the electromagnetic wave generation means 4 of this example includes a generation source 41 of electromagnetic waves (light) and a reflector 42 (reflecting plate) for guiding the electromagnetic waves generated by the generation source 41 toward the mold 2. Yes. The reflector 42 is disposed behind the electromagnetic wave generation source 41 (the direction opposite to the direction in which the mold 2 is disposed) and has a curved reflecting surface 421. The electromagnetic wave generation means 4 of this example is configured to guide most of the electromagnetic waves emitted from the electromagnetic wave generation source 41 in the direction of the mold 2 by the reflector 42.
The electromagnetic wave generating means 4 of this example is a near-infrared halogen heater, and a near-infrared halogen lamp having a light intensity peak in the vicinity of about 1.2 μm in the near-infrared region is used as the electromagnetic wave generation source 41. .

Further, the glass filter 52 of this example is quartz glass that reduces the amount of transmission of electromagnetic waves having a wavelength exceeding 2 μm. The rubber filter 51 of this example is made of silicone rubber, which is the same material as the mold 2. Then, the absorbance of the rubber filter 51 (a measure indicating the absorption intensity with respect to light (electromagnetic waves) of a specific wavelength) and the absorbance of the rubber mold 2 can be matched.
Further, in the resin molding apparatus 1 of this example, the molten thermoplastic resin 3 is injected into the cavity 21 of the mold 2 and the molded mold 2 is irradiated with the transmitted electromagnetic wave, whereby the molten thermoplastic resin is melted. The viscosity of 3 is prevented from becoming 5000 poise or more, and a resin molded product is molded.

Next, the method for molding a resin molded product using the resin molding apparatus 1 and the effects in this example will be described in detail.
In this example, when the molten thermoplastic resin 3 is filled in the cavity 21 of the rubber mold 2, a light intensity peak near the wavelength of about 1.2 μm from the electromagnetic wave generating means 4 is obtained. Infrared rays (electromagnetic waves) are emitted, and the electromagnetic waves transmitted through the rubber filter 51 are irradiated to the thermoplastic resin 3 through the mold 2.

At this time, due to the difference in physical properties between the rubber (silicone rubber) and the thermoplastic resin 3 (ABS resin) constituting the mold 2, it is possible to heat the thermoplastic resin 3 to a greater extent than the rubber mold 2. it can. Thereby, the temperature of the thermoplastic resin 3 in the cavity 21 can be maintained higher than the temperature of the mold 2 until the filling of the thermoplastic resin 3 into the cavity 21 is completed.
Therefore, it is possible to prevent poor filling of the thermoplastic resin 3 in the cavity 21 and obtain a good resin molded product.

  By the way, near-infrared rays having a light intensity peak near the wavelength of about 1.2 μm emitted from the electromagnetic wave generating means 4 include electromagnetic waves in the wavelength region absorbed by the rubber constituting the mold 2. Yes. If the electromagnetic wave is directly irradiated from the electromagnetic wave generating means 4 to the mold 2, the mold 21 absorbs the electromagnetic wave from the surface 201 side (the side to which the electromagnetic wave is irradiated). Compared to the inner 202 side to be formed, the surface 201 side directly irradiated with electromagnetic waves is heated more, and the temperature on the front surface 201 side becomes higher than the inner 202 side. Thereby, there exists a possibility that the shaping | molding die 2 may deform | transform.

  On the other hand, as shown in FIG. 1, in this example, a rubber filter 51 made of the same material as the rubber constituting the mold 2 is placed between the electromagnetic wave generating means 4 and the mold 2. A predetermined gap 210 is formed and arranged. Of the electromagnetic waves emitted from the electromagnetic wave generating means 4 and transmitted through the glass filter 52, most of the electromagnetic waves in the wavelength region absorbed by the rubber constituting the mold 2 are absorbed by the rubber filter 51. be able to.

  Thereby, in this example, while the rubber filter 51 is heated, the ratio by which the shaping | molding die 2 is heated can be decreased. In addition, since the predetermined gap 210 exists between the rubber filter 51 and the mold 2, the heat generated in the rubber filter 51 is directed to the surface 201 side (the side to which transmitted electromagnetic waves are irradiated) of the mold 2. It is possible to suppress the transmission.

And while the temperature rise by the surface 201 side of the shaping | molding die 2 can be suppressed, the temperature difference of the surface 201 side of the shaping | molding die 2 and the inside 202 side (side which forms the cavity 21) can be made small.
Therefore, it can suppress that a deformation | transformation arises in the shaping | molding die 2, and it can suppress that the dimensional accuracy of the resin molded product to shape | mold falls with this deformation | transformation. Moreover, the durability of the mold 2 can be improved.

  Furthermore, in this example, the thermoplastic resin 3 can be more effectively heated by disposing the glass filter 52 between the electromagnetic wave generating means 4 and the mold 2. That is, the electromagnetic wave emitted from the electromagnetic wave generating means 4 includes an electromagnetic wave having a wavelength exceeding 2 μm, but by using the glass filter 52, the electromagnetic wave having a wavelength exceeding 2 μm is applied to the mold 2. It is possible to avoid irradiation as much as possible. Thereby, the thermoplastic resin 3 filled in the cavity 21 of the mold 2 can be effectively irradiated with an electromagnetic wave having a wavelength of 2 μm or less. Therefore, the thermoplastic resin 3 can be heated more effectively.

  In this example, the electromagnetic wave after passing through the glass filter 52 is irradiated to the rubber filter 51. Thereby, it is possible to prevent the rubber filter 51 from being irradiated with electromagnetic waves having a wavelength exceeding 2 μm as much as possible, and to reduce the heating amount of the rubber filter 51. Therefore, deformation of the rubber filter 51 can be suppressed, and the durability of the rubber filter 51 can be improved.

  Therefore, according to the resin molding apparatus 1 and the resin molding method of this example, the thermoplastic resin 3 in the cavity 21 can be selectively heated with respect to the rubber mold 2, and the mold 2 and the rubber The durability of the filter 51 can be improved.

  In this example, an ABS resin was used as the thermoplastic resin 3. As the thermoplastic resin 3, various other heats that can absorb the transmitted electromagnetic wave that is not absorbed in the mold 2 when the surface 201 of the mold 2 is irradiated with the transmitted electromagnetic wave. A plastic resin 3 can be used.

  FIG. 2 shows an example of light transmittance of each silicone rubber, with the horizontal axis representing wavelength (nm) and the vertical axis representing light transmittance (%) for transparent silicone rubber and translucent silicone rubber. It is a graph which shows. In the figure, it can be seen that each silicone rubber transmits light having a wavelength between 200 and 2200 (nm). Therefore, when the electromagnetic wave (light) in this wavelength region is irradiated onto the surface 201 of the silicone rubber mold 2, most of the electromagnetic wave can be transmitted through the mold 2 and absorbed by the thermoplastic resin 3. .

In the same figure, it means that the light that does not pass through the silicone rubber is absorbed by the silicone rubber. In particular, it can be seen that electromagnetic waves having a wavelength of around 1700 (nm) or the like are largely absorbed by the silicone rubber. Therefore, in this example, by irradiating the mold 2 with the transmitted electromagnetic wave after passing through the rubber filter 51 made of silicone rubber, the electromagnetic filter having a wavelength of around 1700 (nm) in particular is applied to the rubber filter. 51 can be absorbed.
Thereby, the heat_generation | fever of the shaping | molding die 2 can be suppressed as much as possible, and it can suppress that the shaping | molding die 2 thermally deteriorates as much as possible.

(Example 2)
This example shows a more specific configuration of the resin molding apparatus 1 as shown in FIGS. 3 to 6 and shows an example in which the thermoplastic resin 3 is filled in the cavity 21 of the molding die 2 in a vacuum state.
As shown in FIGS. 3 and 4, the mold 2 of this example is disposed in a pressure vessel 61 that can be depressurized and increased, and the pressure vessel 61 is evacuated. A vacuum pump 62 is provided. The pressure vessel 61 is configured to be depressurized to a vacuum state by the vacuum pump 62 before the injection of the thermoplastic resin 3 into the cavity 21 and to be increased to a pressure state higher than the atmospheric pressure after the injection. It is.

  The mold 2 of this example forms a cavity 21 between the upper and lower mold components 22, and the upper and lower mold components 22 are clamped by a pair of glass plates 63 (upper and lower mold components). The part 22 is tightened so as not to open. The lower glass plate 63 </ b> B is provided on an elevating platform 64 that can be raised and lowered, and the upper glass plate 63 </ b> A is fixed in the pressure vessel 61. Then, the upper and lower mold components 22 placed on the lower glass plate 63B are pressed against the upper glass plate 63A by the lifting platform 64, thereby clamping the upper and lower mold components 22 (molding die 2). It can be performed.

Further, as shown in FIGS. 3 and 4, the electromagnetic wave generating means 4 of this example is disposed above the outside of the pressure vessel 61, and the glass filter 52 of this example is provided on the upper wall of the pressure vessel 61. It is provided as a transparent window part constituting a part. Further, the rubber filter 51 of the present example is provided corresponding to the location where the cavity 21 is formed on the upper surface 201 of the upper mold component 22A. The rubber filter 51 is disposed on the upper mold component 22A via a spacer 511, thereby forming a predetermined gap 210 between the rubber filter 51 and the upper surface 201 of the upper mold component 22A.
Further, the mold 2 is formed with an injection port 23 for guiding the molten thermoplastic resin 3 to the cavity 21.

As shown in FIGS. 4 and 5, the thermoplastic resin 3 before filling into the cavity 21 is formed as a resin solid body 31 formed to have a capacity larger than that for filling the cavity 21. A stocker 65 for storing a plurality of resin solid bodies 31 is disposed in the pressure vessel 61, and a holding portion 66 for heat-melting and holding the resin solid bodies 31 is disposed adjacent to the stocker 65. It is.
As shown in FIG. 3, the holding unit 66 is provided with a heater 661 such as a band heater, and the heater 661 heats and melts the resin solid body 31 transferred from the stocker 65 into the holding unit 66. be able to. Further, at the time of this heat-melting, the electromagnetic wave can be irradiated from the electromagnetic wave generating means 4 to the resin solid body 31.

  As shown in the figure, the holding part 66 injects the molten thermoplastic resin 3 into a position below the electromagnetic wave generating means 4 (position to heat and melt) and an position above the injection port 23 of the mold 2 (injection port 23). The position is moved between the position and the position. The stocker 65 and the holding part 66 are arranged on a moving plate 67, and a guide part 68 for guiding the movement of the moving plate 67 is provided in the pressure vessel 61.

Next, a method for molding a resin molded product using the resin molding apparatus 1A of this example will be described in detail.
In this example, a resin molded product is obtained from the thermoplastic resin 3 by performing the following vacuum process, preheating process, filling process, and cooling extraction process.
In molding a resin molded product, first, as a vacuum process, the vacuum pump 62 is used to evacuate the pressure vessel 61 so that the cavity 21 of the rubber mold 2 is evacuated.

As shown in FIGS. 3 and 4, as a preheating step, one of the resin solid bodies 31 stored in the stocker 65 is transferred into the holding unit 66, and this resin solid body 31 is transferred to the heater 661 and electromagnetic wave generation. It is heated and melted using means 4. At this time, the resin discharge port 663 formed at the bottom of the holding portion 66 is closed by the shutter 662.
Next, as shown in FIG. 6, as a filling step, the holding portion 66 is moved from the lower position of the electromagnetic wave generating means 4 to the upper position with respect to the injection port 23 of the mold 2 by the moving plate 67, and the shutter 662 is opened to hold the holding portion. The thermoplastic resin 3 in 66 is injected into the cavity 21 through the injection port 23 in the mold 2. This injection can be performed by utilizing the weight of the thermoplastic resin 3.

Further, in this example, when performing the preheating step and the filling step, emission of electromagnetic waves by the electromagnetic wave generating means 4 is continued, and the mold 2 is transmitted through the glass filter 52 and the rubber filter 51. Irradiate later transmitted electromagnetic waves.
While the cavity 21 is filled with the thermoplastic resin 3, the thermoplastic resin 3 can be selectively heated compared to the mold 2, and the molten thermoplastic injected from the holding portion 66. The temperature of the resin 3 can be prevented from decreasing.

Next, after injecting the thermoplastic resin 3 into the cavity 21, evacuation by the vacuum pump 62 is stopped and the pressure vessel 61 is opened to the atmosphere so that the pressure vessel 61 is brought into an atmospheric pressure state. Thereby, the thermoplastic resin 3 injected into the cavity 21 can be sufficiently spread over the entire narrow gap or the like in the cavity 21. In this way, the molten thermoplastic resin 3 is filled into the cavity 21.
Thereafter, as a cooling extraction step, the thermoplastic resin 3 in the cavity 21 is cooled to form a resin molded product, and then the molding die 2 is opened, and the molded resin molded product is taken out from the cavity 21.

Further, in this example, the molded resin molded product is cooled by air cooling in the cavity 21 and then taken out from the cavity 21. At this time, since the thermoplastic resin 3 can be selectively heated as described above, the temperature of the mold 2 can be kept lower than the temperature of the thermoplastic resin 3, and cooling required for cooling the resin molded product. Time can be shortened.
Also in this example, other configurations are the same as those of the first embodiment, and the same effects as those of the first embodiment can be obtained.

(Confirmation test)
In this confirmation test, the thermoplastic resin 3 is placed in the cavity 21 for the resin molding apparatus 1 (invention) provided with the rubber filter 51 and the resin molding apparatus (comparative product) not provided with the rubber filter 51. The temperature difference between the temperature of the upper surface 201 (surface on the side irradiated with the electromagnetic wave) of the mold 2 and the temperature of the interior 202 (part of the cavity 21) was measured.
In this confirmation test, the mold 2 and the rubber filter 51 were made of translucent silicone rubber, and the glass filter 52 was made of heat-resistant glass. The electromagnetic wave generating means 4 includes a near-infrared halogen lamp having a light intensity peak in the vicinity of about 1.2 μm in the near-infrared region (irradiation distance to the upper surface 201 of the mold 2; 200 mm, applied voltage; 80V) did. The thermoplastic resin 3 was an AES resin (black).

The thickness of the upper mold component 22A of the mold 2 (the distance from the upper surface 201 irradiated with electromagnetic waves in the mold 2 to the wall surface of the cavity 21) is 10 mm, and the thickness of the glass filter 52 is 10 mm. did. Further, the mold 2 was placed in the pressure vessel 61, and the cavity 21 in a vacuum state was filled with the thermoplastic resin 3.
In this confirmation test, when filling the thermoplastic resin 3 in the cavity 21, the temperature of the thermoplastic resin 3, the temperature of the upper surface 201 of the mold 2 and the temperature of the interior 202 of the mold 2 were measured. It shows in FIG. 7, FIG. FIG. 7 shows the results for the inventive product, and FIG. 8 shows the results for the comparative product.

In both figures, the horizontal axis represents the electromagnetic wave irradiation time (minutes), the vertical axis represents the temperature (° C.), and the temperature of the thermoplastic resin 3 after the heating by the electromagnetic wave generating means 4 is started. 2 shows the state of changes in the temperature of the upper surface 201 of 2 and the temperature of the inside 202 of the mold 2.
From FIG. 8, it can be seen that for the comparative product, the temperature of the upper surface 201 of the mold 2 rises to 165 ° C. or higher, while the temperature of the interior 202 of the mold 2 rises to about 110 ° C. It can be seen that there is a temperature difference of about 55 ° C. between the temperature of the upper surface 201 and the temperature of the interior 202. On the other hand, from FIG. 7, it can be seen that the temperature of the upper surface 201 of the mold 2 rises to about 120 ° C. and the temperature of the inside 202 of the mold 2 rises to about 95 ° C. for the invention. It can be seen that the temperature difference between the temperature of the upper surface 201 and the temperature of the interior 202 is about 25 ° C.

  From these results, according to the invention (resin molding apparatus 1 provided with the rubber filter 51), the temperature difference between the surface 201 side and the inside 202 side of the mold 2 can be reduced, which is caused by the temperature difference. It was found that the deformation of the mold 2 to be performed can be suppressed. Further, according to the invention, it was found that the temperature rise of the entire mold 2 can be suppressed, and the durability of the mold 2 can be further improved.

FIG. 3 is an explanatory view showing a resin molding apparatus in Example 1. In Example 1, the wavelength (nm) is taken on a horizontal axis | shaft and the light transmittance (%) is taken on the vertical axis | shaft, and the graph which shows the light transmittance about transparent silicone rubber and translucent silicone rubber. Sectional explanatory drawing which shows the resin molding apparatus in Example 2 before filling the cavity with the thermoplastic resin in the state seen from the front. Sectional explanatory drawing which shows the resin molding apparatus in Example 2 before filling a cavity with a thermoplastic resin in the state seen from the side. Sectional explanatory drawing which shows the resin molding apparatus in Example 2 in the state seen from upper direction. Sectional explanatory drawing which shows the state which looked at the resin molding apparatus in the state filled with the thermoplastic resin in Example 2 from the front in Example 2. FIG. Regarding the invention of the confirmation test, the horizontal axis represents the electromagnetic wave irradiation time (minutes), the vertical axis represents the temperature (° C.), and the temperature of the thermoplastic resin after the heating by the electromagnetic wave generating means is started. The graph which shows the state of the change of the temperature of an upper surface, and the temperature inside a shaping | molding die. For the comparative product in the confirmation test, the horizontal axis represents the electromagnetic wave irradiation time (minutes), the vertical axis represents the temperature (° C.), and the temperature of the thermoplastic resin after the heating by the electromagnetic wave generating means is started. The graph which shows the state of the change of the temperature of an upper surface, and the temperature inside a shaping | molding die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin molding apparatus 2 Mold 201 Surface 202 Inside 21 Cavity 210 Gap 3 Thermoplastic resin 4 Electromagnetic wave generation means 51 Rubber filter 52 Glass filter 61 Pressure vessel 62 Vacuum pump

Claims (16)

A rubber molding die formed with a cavity for filling a thermoplastic resin;
An electromagnetic wave generating means for emitting an electromagnetic wave having a wavelength of 0.78 to 2 μm;
Between the electromagnetic wave generating means and the mold, a predetermined gap is formed with respect to the mold, and the wavelength region of the electromagnetic waves emitted from the electromagnetic wave generating means is absorbed by the mold. And having a rubber filter that absorbs at least the peak electromagnetic wave in the wavelength region,
When the thermoplastic resin is filled in the cavity, the electromagnetic wave emitted from the electromagnetic wave generating means is transmitted through the rubber filter, and the transmitted electromagnetic wave after passing through the rubber filter is converted into the molding. A resin molding apparatus configured to irradiate the thermoplastic resin through a mold. A rubber molding die formed with a cavity for filling a thermoplastic resin;
An electromagnetic wave generating means for emitting an electromagnetic wave having a wavelength of 0.78 to 4 μm;
A glass filter which is disposed between the electromagnetic wave generating means and the mold and reduces the amount of electromagnetic waves having a wavelength exceeding 2 μm;
Between the glass filter and the mold, a predetermined gap is formed with respect to the mold, and the electromagnetic wave transmitted through the glass filter has a wavelength region that is absorbed by the mold. And having a rubber filter that absorbs at least the peak electromagnetic wave in the wavelength region,
When filling the cavity with the thermoplastic resin, the electromagnetic wave emitted from the electromagnetic wave generating means is transmitted through the glass filter and the rubber filter, and is transmitted through the glass filter and the rubber filter. A resin molding apparatus configured to irradiate the thermoplastic resin through the molding die with the transmitted electromagnetic wave after being formed.   3. The resin molding apparatus according to claim 2, wherein the glass filter is quartz glass that reduces the amount of electromagnetic waves transmitted with a wavelength exceeding 2 μm.   The resin molding apparatus according to claim 1, wherein the rubber filter is made of the same material as the molding die.   5. The resin molding apparatus according to claim 4, wherein the molding die and the rubber filter are made of silicone rubber. 6. The vacuum pump according to claim 1, wherein the molding die is disposed in a pressure vessel capable of depressurization and pressure increase, and the pressure vessel includes a vacuum pump that evacuates the pressure vessel. Is provided,
The inside of the pressure vessel is configured to be depressurized to a vacuum state by the vacuum pump before the injection of the thermoplastic resin into the cavity, and to be increased to a pressure state higher than the atmospheric pressure after the injection. The resin molding apparatus characterized by the above-mentioned.   The resin molding apparatus according to claim 1, wherein the electromagnetic wave generating unit emits an electromagnetic wave having an intensity peak in a wavelength region of 0.78 to 2 μm. A resin molding method for filling a thermoplastic resin into a cavity of a rubber mold and cooling the thermoplastic resin to obtain a resin molded product,
When the thermoplastic resin is filled in the cavity, an electromagnetic wave generating means for emitting an electromagnetic wave having a wavelength of 0.78 to 2 μm, and between the electromagnetic wave generating means and the mold, with respect to the mold A rubber filter that is arranged to form a predetermined gap and that absorbs at least the peak electromagnetic wave in the wavelength region of the electromagnetic wave emitted from the electromagnetic wave generating means and absorbed by the mold. Use
The electromagnetic wave emitted from the electromagnetic wave generating means is transmitted through the rubber filter, and the electromagnetic wave transmitted through the rubber filter is irradiated onto the thermoplastic resin through the molding die to thereby generate the heat. A resin molding method comprising heating a plastic resin. A resin molding method for filling a thermoplastic resin into a cavity of a rubber mold and cooling the thermoplastic resin to obtain a resin molded product,
When the thermoplastic resin is filled in the cavity, an electromagnetic wave generating means for emitting an electromagnetic wave having a wavelength of 0.78 to 4 μm is disposed between the electromagnetic wave generating means and the mold, and the wavelength is set to 2 μm. A glass filter that reduces the amount of transmission of electromagnetic waves exceeding, and an electromagnetic wave that is disposed between the glass filter and the mold so as to form a predetermined gap with respect to the mold and is transmitted through the glass filter. Among them, using a rubber filter that absorbs electromagnetic waves at least in the wavelength region of the wavelength region that is absorbed by the mold,
The electromagnetic wave emitted from the electromagnetic wave generating means is transmitted through the glass filter and the rubber filter, and the transmitted electromagnetic wave after passing through the glass filter and the rubber filter is transmitted through the mold. A resin molding method comprising irradiating a thermoplastic resin to heat the thermoplastic resin.   10. The resin molding method according to claim 9, wherein the glass filter is quartz glass that reduces the amount of electromagnetic waves transmitted with a wavelength exceeding 2 μm.   11. The resin molding method according to claim 8, wherein the rubber filter is made of the same material as the molding die.   12. The resin molding method according to claim 11, wherein the molding die and the rubber filter are made of silicone rubber. The vacuum pump according to any one of claims 8 to 12, wherein the molding die is arranged in a pressure vessel capable of depressurization and pressure increase, and the pressure vessel includes a vacuum state in the pressure vessel. Is provided,
Before the injection of the thermoplastic resin into the cavity, the pressure inside the pressure vessel is reduced to a vacuum state by the vacuum pump, and after the injection, the inside of the pressure vessel is increased to a pressure state higher than atmospheric pressure. A resin molding method characterized by pressing.   14. The resin molding method according to claim 8, wherein the electromagnetic wave generating means emits an electromagnetic wave having an intensity peak in a wavelength region of 0.78 to 2 μm.   The resin molding method according to any one of claims 8 to 14, wherein the thermoplastic resin is heated to a temperature higher than that of the molding die.   The resin molding method according to any one of claims 8 to 15, wherein the thermoplastic resin is heated to prevent the viscosity of the thermoplastic resin from reaching 5000 poise or more.

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