JPH1190962A - Resin molding method and mold for resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin molding method and a resin molding die thereof for absorbing properly the generation of sink marks and molding resin with high accuracy. SOLUTION: A cavity 8 is formed of molds 2 and 3, cavity pieces 4 and 5, a transfer face 6a of the cavity piece 6 and a transfer face 7a of the cavity piece 7 in an injection molding die 1, and molten resin 9 is filled from a resin introduction line into the cavity 8. Then the resin 9 is bonded on the transfer faces 6a and 7a of the transfer pieces 6 and 7, and then the resin 9 is cooled to lower than the softening temperature, and at that time, a filling material 12 is introduced between a part of the whole of a face on the side of a cavity 8 of the cavity piece 4 having no transfer face and the resin 9 in the cavity 8 through a filling material introduction line 11. When the filling material 12 is introduced between the cavity piece 4 and the resin 9, the cooling rate of the resin 9 on a section bonded with the filling material 12 is slower than those of other sections and movable more easily to absorb the shrinkage of resin 9 by cooling by the filling material 12 and also by a section whereon the resin 9 is brought into contact with the filling material 12 and improve the transfer accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding method and a resin molding die, and more particularly, to a laser type digital copying machine, an optical scanning system of a laser printer or a facsimile apparatus, an optical apparatus such as a video camera, and the like. The present invention relates to a resin molding method for a plastic molded product applied to an optical disk or the like and a resin molding die.

[0002]

2. Description of the Related Art As a method of performing plastic molding (resin molding), there are an injection molding method and an injection compression molding method. In this injection molding method, a molten resin is injected and filled into a cavity of a fixed volume of a mold while the mold temperature is set to be lower than a softening temperature of a molding resin. This is a method of opening the mold and taking out the molded product. In the injection compression molding method, a transfer piece that forms a transfer surface in a mold is movable, and molten resin is injected into a cavity having a predetermined volume while the mold temperature is lower than the softening temperature of the molding resin. Filling,
When gradually cooling while controlling the holding pressure, slide the transfer piece in response to the volume contraction of the resin during cooling, apply pressure to the resin, and form the shape of the molded product with higher precision How to

In these molding methods, it is generally desirable that the resin pressure and the resin temperature in the mold become uniform when the resin is cooled and solidified, in order to secure a desired shape accuracy in a molded product. .

[0004]

However, such a plastic molding method has heretofore had the following problems.

That is, in the injection molding method, when the molded article has an uneven thickness having a thick portion and a thin portion, the resin temperature becomes uneven at the thick portion and the thin portion during cooling, and the resin remains at the thin portion. There was a problem that pressure was generated and sinks were generated in a thick portion. Further, in a thick-walled molded product, sink occurs easily due to a large amount of volume shrinkage in the process of cooling the resin. Therefore, when the filling pressure is increased to prevent sink marks, there is a disadvantage that the residual strain increases, and a highly accurate molded product cannot be obtained.

[0006] In addition, the injection compression molding method can perform molding at a lower filling pressure than the injection molding method. However, when the molded article has an uneven thickness, a difference in shrinkage occurs due to the thickness of the molded article. Since the transfer piece cannot follow the shrinkage of the resin and cannot apply a uniform pressure, there is a problem that sinks occur in a portion where the pressure is low and the shape accuracy is reduced.

In such a case, a method is employed in which the temperature of the mold is increased to a temperature higher than the softening temperature of the resin during molding, and each part of the molded article is gradually cooled in the cooling process so as to be as constant as possible.
Although the above-mentioned problem is solved, a new problem that the molding time is long and the cost is high occurs.

Conventionally, in an injection molding method, a molten resin is introduced into a cavity of a molding die in which a porous member communicating with a compressed gas source is provided on at least a part of a die surface in contact with a non-optical surface of a molded product. And pressurizing the non-optical surface of the molded article with the gas flowing through the compressed gas source and the porous member during the cooling process from the holding pressure, thereby increasing the height of the plastic lens that solves the above-mentioned problems. A precision molding method and a molding apparatus therefor have been proposed (JP-A-2-1751).
No. 15).

However, this technique has a problem that it can be applied only to injection molding and cannot be applied to injection compression molding. In addition, the porous member is mainly made of ceramics, and is easier to maintain (durable) than steel, which is a commonly used cavity member.
There was a problem that it was inferior. In addition, this prior art
By injecting compressed gas, the thermal conductivity is lower than other molding surfaces including the transfer surface, and cooling is delayed,
Since the transfer accuracy of the transfer surface is improved by the pressure propagation received from the compressed gas, when the heat capacity of the cavity member or the molded product changes, the temperature distribution in the cavity changes,
There is a problem that it is difficult to reliably induce sink marks, and the reproducibility of repetition deteriorates.

Therefore, according to the present invention, at least one cavity is defined by at least one cavity piece having a transfer surface and at least one cavity piece having no transfer surface. Using a pair of molds, filling the cavity with the molten resin heated above the softening temperature, transferring the transfer surface to the resin, and cooling the resin below the softening temperature has a transfer surface A predetermined filling substance is interposed between at least one of the cavity pieces that are not filled and the resin, and sinks generated in the resin at the time of cooling are absorbed by a portion in contact with the filling substance of the resin, thereby filling the resin. The resin is pressed more appropriately by the transfer surface with the substance, and the resin and the cavity piece are separated by the filler substance, so that the cooling rate of the portion in contact with the resin filler substance is reduced. To reduce the shrinkage of the other part of the resin at the part in contact with the filling material of the resin, to prevent sinking of the resin molded product and to improve the transfer accuracy. It is an object of the present invention to provide a resin molding method that can be used.

According to a second aspect of the present invention, at least one cavity is defined by at least one cavity piece having a transfer surface and at least one cavity piece having no transfer surface. Using a pair of molds, filling the cavity with molten resin heated to a temperature equal to or higher than the softening temperature, transferring the transfer surface to the resin, and cooling the resin below the softening temperature, does not have a transfer surface A predetermined filling substance is interposed between at least one of the cavity pieces among the cavity pieces and the resin, and sinks generated in the resin at the time of cooling are absorbed by a portion in contact with the filling substance of the resin, whereby the filling substance is used. The resin is more appropriately pressed against the transfer surface, and the resin is separated from the cavity piece by the filler material. A resin that absorbs the shrinkage of other parts of the resin at the part in contact with the filler material of the resin, thereby preventing sink marks of the resin molded product and improving transfer accuracy. It is intended to provide a molding die.

According to a third aspect of the present invention, a filling material introducing passage communicating between the inside of the cavity and the outside of the mold is formed in the cavity piece having no transfer surface, and an evaporating foaming agent is used as the filling material. Then, the evaporation type foaming agent is heated and evaporated by a heating means provided outside the mold, and has a transfer surface in the cavity as a foaming gas from the heating means through a gas introduction pipe and a filling substance introduction passage. By introducing the foaming gas into the cavity at a free timing and in a free amount while simplifying the mold structure by introducing it between the cavity piece and the resin which is not inexpensive, An object of the present invention is to provide a resin molding method and a resin molding die having good transfer accuracy.

According to a fourth aspect of the present invention, in a cavity piece having no transfer surface, a filling material introduction passage communicating between the inside of the cavity and the outside of the mold is formed, and a liquid evaporative foam is used as the filling material. Using an agent, the liquid evaporative foaming agent is passed through a liquid introduction pipe and a filling substance introduction passage from a pressurizing means provided outside the mold, and a cavity piece having no transfer surface in the cavity and a resin. By reacting with the temperature of the molten resin to generate a foaming gas,
Without using a heat source, an evaporating foaming agent is introduced into the cavity at a free timing and in a free amount. It is intended to provide.

According to a fifth aspect of the present invention, a filling material introduction passage communicating between the inside of the cavity and the outside of the mold is formed in the cavity piece having no transfer surface, and a reactive foaming agent is used as the filling material. Then, the reaction type foaming agent is reacted by a reaction means provided outside the mold, and as a foaming gas, a cavity piece having no transfer surface in the cavity and a resin are passed through a gas introduction pipe and a filler introduction path. By introducing the foaming gas into the cavity at a free timing and in a free amount without using a special device such as a heat source or a pressure source, the cost can be further reduced and An object of the present invention is to provide a resin molding method and a resin molding die having good transfer accuracy.

According to a sixth aspect of the present invention, the resin filled in the cavity is formed by forming at least the end of the filling material introduction passage formed in the cavity piece that opens into the cavity to a size of 0.1 mm or less. Prevents clogging the filling substance introduction passage and blocking the filling substance introduction passage,
It is an object of the present invention to provide a resin molding method and a resin molding die having good usability and good transfer accuracy.

[0016] The invention according to claim 7 is characterized in that:
By using a decomposition type foaming agent and arranging it on the surface facing the cavity of the cavity piece without a transfer surface in the cavity before filling the resin into the cavity, if only injection molding and injection compression molding Transfer molding (transfer molding), casting (casting)
And RIM (reaction injection molding: reaction injection molding), etc., and there is no need to provide a special device for supplying the filling material into the cavity or to provide a filling material introduction passage in the cavity. It is an object of the present invention to provide a resin molding method and a resin molding die with better transferability and better transfer accuracy at a lower cost.

The invention according to claim 8 is characterized in that the decomposition type foaming agent comprises
A resin molding method and a resin molding die that are easy to handle the decomposable foaming agent by coating with a predetermined film, are more usable, and are more inexpensive with good transfer accuracy. It is intended to be.

The invention according to claim 9 is characterized in that the decomposition type foaming agent is
By being coated on the carrier in a state of being mixed with a predetermined carrier, the handling of the decomposable foaming agent is facilitated, the utilization is more favorable, and the transfer accuracy is better at a lower cost. It is an object of the present invention to provide a resin molding method and a resin molding die.

According to a tenth aspect of the present invention, by using a decomposable foaming agent that melts at a predetermined foaming temperature, the decomposable foaming agent adheres to a resin molded product after the resin is molded, It is an object of the present invention to provide a resin molding method and a resin molding die that can be easily taken out of a mold, are more usable, and have better transfer accuracy at a lower cost.

The eleventh aspect of the present invention is to provide a decomposable foaming agent that is softened or changes into a rubbery state at the foaming temperature of the decomposable foaming agent as a coating or a carrier for coating the decomposable foaming agent. In addition to facilitating handling and improving the applicability, the decomposition type foaming agent is prevented from sticking to the resin molded product after the resin is molded, and can be easily removed from the mold. It is an object of the present invention to provide a resin molding method and a resin molding die that are more usable and more excellent in transfer accuracy at a lower cost.

According to a twelfth aspect of the present invention, in the state where the decomposable foaming agent is mixed with the carrier coated with the coating or the carrier, the foaming agent coated with the carrier has a predetermined size and a predetermined size. At least one protrusion
One or more of the cavity pieces that are formed and have no transfer surface by the projections are arranged on the surface of at least one of the cavity pieces, so that the split-type foaming agent can be reliably separated from the cavity surface. It is an object of the present invention to provide a resin molding method and a resin molding die which can be held at a higher temperature, are more usable, and have a better transfer accuracy at a lower cost.

According to a thirteenth aspect of the present invention, a non-volatile gas is filled in a predetermined coating which softens or changes into a rubbery state at a temperature lower than a molding temperature of a resin as a filling substance. It is possible to increase and decrease the volume of the filling material by a change in temperature, to secure the reusability of the filling material, to make the resin molding method and the resin molding metal more inexpensive and more excellent in transfer accuracy. It is intended to provide a type.

According to a fourteenth aspect of the present invention, at least one of the cavity pieces having no transfer surface is provided so as to be movable by a predetermined amount in a direction in which the volume of the cavity is increased in accordance with the pressure in the cavity filled with the resin. By moving the cavity piece, it is possible to prevent the pressure in the cavity from being excessive due to the filling material, thereby preventing unnecessary distortion from occurring in the resin molded product, and further improving the molding quality. It is an object of the present invention to provide a resin molding method and a resin molding die.

According to a fifteenth aspect of the present invention, the pressure in the cavity is increased by the filling substance by moving the cavity piece by a hydraulic cylinder or the like which is attached to the outside of the mold for moving the mold. The excess is prevented by moving the cavity piece at low cost, preventing unnecessary distortion from occurring in the resin molded product at low cost, and further reducing the cost.
Further, it is an object of the present invention to provide a resin molding method and a resin molding die having better molding quality.

According to a sixteenth aspect of the present invention, the cavity piece is moved by the pressure generated by the filling material in the cavity, so that the pressure in the cavity becomes excessive due to the filling material. The present invention provides a resin molding method and a resin molding die that can prevent unnecessary distortion from occurring in a resin molded product at a low cost, and that are more inexpensive and have better molding quality. It is intended to be.

According to a seventeenth aspect of the present invention, at least one of the cavity pieces having no transfer surface is provided with a predetermined elastic body between the cavity plate and the cavity piece provided on the back surface of the cavity piece. Then, the elastic body is pressed by the pressure generated by the filling material in the cavity, and is disposed so as to be movable in a direction to increase the volume of the cavity. Move the cavity piece to prevent it,
An object of the present invention is to provide a resin molding method and a resin molding die that prevent unnecessary distortion from occurring in a resin molded product at a low cost, and that are more inexpensive and have higher molding quality.

[0027]

According to a first aspect of the present invention, there is provided a resin molding method comprising at least one cavity piece having a transfer surface and at least one cavity piece having no transfer surface. A resin molding method for transferring the transfer surface to a resin filled in a cavity using a pair of molds in which one or more cavities are defined, wherein the cavity is heated to a softening temperature or higher. After filling the molten resin, the resin is brought into close contact with the transfer surface by the resin pressure generated in the cavity, and the transfer surface is transferred to the resin, and then the resin is cooled below the softening temperature. At this time, a predetermined filling material is interposed between at least one of the cavity pieces having no transfer surface and the resin, and the cooling is performed. The shrinkage that occurs in the resin by absorbing at a portion in contact with the filler material of the resin to have achieved the above objects.

According to the above arrangement, at least one cavity piece having a transfer surface and at least one cavity piece having no transfer surface have at least one cavity piece.
Using a pair of molds in which one or more cavities are defined, filling the cavities with molten resin heated above the softening temperature, transferring the transfer surface to the resin, and cooling the resin below the softening temperature In this case, a predetermined filling material is interposed between at least one of the cavity pieces having no transfer surface and the resin, and a sink which occurs in the resin at the time of cooling is brought into contact with the filling material of the resin. The resin can be more appropriately pressed against the transfer surface by the filling material, and the resin is separated from the cavity piece by the filling material, so that the cooling rate of the portion in contact with the resin filling material can be reduced by another. When it is slower than the part, the shrinkage of the other part of the resin can be absorbed by the part in contact with the filling material of the resin, and the occurrence of sink in the resin molded product can be prevented. Moni, thereby improving the transfer accuracy.

According to the second aspect of the present invention, at least one cavity has at least one cavity piece having at least one cavity piece having a transfer surface and at least one cavity piece having no transfer surface. The cavity is filled with a molten resin heated to a temperature equal to or higher than the softening temperature, and the resin is brought into close contact with the transfer surface by a resin pressure generated in the cavity to transfer the transfer surface to the resin. Then, the resin molding die to cool the resin below the softening temperature, between the resin and at least one or more of the cavity pieces of the cavity pieces not having the transfer surface, The above object is achieved by interposing a predetermined filling material and absorbing sink marks generated in the resin at the time of the cooling at a portion of the resin in contact with the filling material. That.

According to the above arrangement, at least one cavity piece having a transfer surface and at least one cavity piece having no transfer surface have at least one cavity piece.
Using a pair of molds in which one or more cavities are defined, filling the cavities with molten resin heated above the softening temperature, transferring the transfer surface to the resin, and cooling the resin below the softening temperature In this case, a predetermined filling material is interposed between at least one of the cavity pieces having no transfer surface and the resin, and a sink which occurs in the resin at the time of cooling is brought into contact with the filling material of the resin. The resin can be more appropriately pressed against the transfer surface by the filling material, and the resin is separated from the cavity piece by the filling material, so that the cooling rate of the portion in contact with the resin filling material can be reduced by another. When it is slower than the part, the shrinkage of the other part of the resin can be absorbed by the part in contact with the filling material of the resin, and the occurrence of sink in the resin molded product can be prevented. Moni, thereby improving the transfer accuracy.

In each of the above cases, for example, as described in claim 3, in the cavity piece having no transfer surface, a filling material introduction passage communicating between the inside of the cavity and the outside of the mold is formed. The filling material is an evaporating foaming agent, and is heated and evaporated by heating means provided outside the mold, and as a foaming gas, a gas introduction pipe connecting the heating means and the filling material introduction passage, and The resin may be introduced between the cavity piece having no transfer surface in the cavity and the resin through the filling material introduction passage.

According to the above construction, a filling material introduction passage communicating between the inside of the cavity and the outside of the mold is formed in the cavity piece having no transfer surface, and an evaporating foaming agent is used as the filling material. The evaporating foaming agent is heated and evaporated by a heating means provided outside the mold, and has no transfer surface in the cavity as a foaming gas from the heating means through a gas introduction pipe and a filling substance introduction passage. Since it is introduced between the cavity piece and the resin, the foaming gas can be supplied into the cavity at a free timing and in a free amount while simplifying the mold structure, and the resin molding can be performed at low cost. And the transfer accuracy can be improved.

Further, for example, in the cavity piece having no transfer surface, a filling material introduction passage communicating between the inside of the cavity and the outside of the mold is formed, and The filling substance is a liquid evaporative foaming agent, and is passed through a liquid introduction pipe and the filling substance introduction passage connecting the pressurizing means and the filling substance introduction passage by a pressure means arranged outside the mold. The resin may be introduced between the cavity piece having no transfer surface in the cavity and the resin and react with the temperature of the molten resin to generate a foaming gas.

According to the above construction, a filling substance introduction passage communicating between the inside of the cavity and the outside of the mold is formed in the cavity piece having no transfer surface, and a liquid evaporating foaming agent is used as the filling substance. The liquid evaporating foaming agent is used to press the resin between the cavity piece having no transfer surface in the cavity and the resin through the liquid introduction pipe and the filling substance introduction passage from the pressurizing means disposed outside the mold. In between, the foamed gas is generated by reacting with the temperature of the molten resin to generate a foaming gas, so that the evaporating foaming agent can be introduced into the cavity by a free amount at any time without using a heat source, Can be formed at a lower cost, and the transfer accuracy can be further improved.

Further, for example, as described in claim 5, in the cavity piece having no transfer surface, a filling substance introduction passage communicating between the inside of the cavity and the outside of the mold is formed, The filling substance is a reactive foaming agent, and is reacted by a reaction means provided outside the mold, and as a foaming gas, a gas introduction pipe connecting the reaction means and the filling substance introduction passage and the filling substance introduction path. Through the passage
The resin may be introduced between the cavity piece having no transfer surface in the cavity and the resin.

According to the above-described structure, a filling material introduction passage communicating between the inside of the cavity and the outside of the mold is formed in the cavity piece having no transfer surface, and a reactive foaming agent is used as the filling material. The reaction type foaming agent is caused to react by a reaction means disposed outside the mold, and as a foaming gas, the gas passes through the gas introduction pipe and the filling material introduction passage, and the cavity piece having no transfer surface in the cavity and the resin. Since it is introduced in the middle, the foaming gas can be introduced into the cavity at any time and at any time without using a special device such as a heat source or a pressure source, and the resin can be molded at a lower cost. And the transfer accuracy can be further improved.

Further, for example, as set forth in claim 6, the filler introduction passage formed in the cavity piece has at least an end opening to the cavity,
It may be formed in a size of 0.1 mm or less.

According to the above configuration, since at least the end of the filler introduction passage formed in the cavity piece that opens into the cavity is formed to have a size of 0.1 mm or less, the resin filled in the cavity can be filled with resin. It is possible to prevent clogging of the filling material introduction passage and blocking of the filling material introduction passage, so that the resin molding method and the resin molding die have good availability and good transfer accuracy. it can.

Further, for example, as described in claim 7, the filling material is a decomposable foaming agent, and has the transfer surface in the cavity before the resin is filled in the cavity. It may be arranged on the surface of the cavity piece not facing the cavity.

According to the above construction, a decomposable foaming agent is used as a filling material, and before the resin is filled into the cavity, the resin is arranged on the surface of the cavity piece having no transfer surface in the cavity facing the cavity. It can be applied not only to injection molding and injection compression molding, but also to transfer molding (casting), RIM (reaction injection molding), etc. It is possible to eliminate the need for a special device for supplying the filling substance into the cavity or to provide a filling substance introduction passage in the cavity, so that the resin molding method and the resin molding die can be used even more favorably. In addition, the transfer accuracy can be improved more inexpensively.

Further, for example, as described in claim 8, the decomposition type foaming agent may be covered with a predetermined film.

According to the above configuration, since the decomposable foaming agent is covered with the predetermined coating, the handling of the decomposable foaming agent can be facilitated, and the resin molding method and the resin molding die can be improved. The transferability can be further improved and the transfer accuracy can be improved more inexpensively.

Further, for example, as described in claim 9, the decomposition-type foaming agent may be coated on the carrier in a state of being mixed with a predetermined carrier.

According to the above configuration, the decomposition-type foaming agent is coated on the carrier in a state of being mixed with a predetermined carrier, so that the handling of the decomposition-type foaming agent can be facilitated, and The molding method and the resin molding die can be made more usable, more inexpensive, and more excellent in transfer accuracy.

Further, for example, the decomposition type foaming agent may be one that melts at a predetermined foaming temperature.

According to the above configuration, as the decomposable foaming agent,
Since a resin that melts at a predetermined foaming temperature is used, the decomposition-type foaming agent can be stuck to the resin molded product after the resin is molded, and can be easily removed from the mold. It is possible to make the mold more easily usable, more inexpensively, and more excellent in transfer accuracy.

Further, for example, as described in claim 11, the coating or the carrier covering the decomposable foaming agent softens or changes into a rubbery state at the foaming temperature of the decomposable foaming agent. You may.

According to the above configuration, as the coating or carrier covering the decomposable foaming agent, one that softens or changes into a rubbery state at the foaming temperature of the decomposable foaming agent is used. And it is possible to improve the usability even more, and it is possible to prevent the decomposable foaming agent from sticking to the resin molded product after the resin is molded, and to easily take it out of the mold. Thus, the resin molding method and the resin molding die can be made more usable, more inexpensive, and more excellent in transfer accuracy.

Further, for example, as described in claim 12, in a state where the decomposable foaming agent is mixed with the filling material covered with the coating or the carrier, the filling material covered with the carrier is At least one protrusion having a predetermined size, which is protruded by a predetermined amount, is formed on the surface of at least one cavity piece among the cavity pieces having no transfer surface by the protrusion. There may be.

[0050] According to the above structure, the decomposable foaming agent is mixed with the filler or the carrier coated with the coating, and as the filler coated with the carrier, the protrusions of a predetermined size projecting by a predetermined amount are formed. Since at least one or more of the cavity pieces having no transfer surface are formed by the projections and arranged on the surface of at least one of the cavity pieces, the split-type foaming agent is separated from the cavity surface. Can be securely held,
The resin molding method and the resin molding die can be made more usable, more inexpensive, and more excellent in transfer accuracy.

Further, for example, as described in claim 13, the non-volatile gas is filled in the predetermined coating material which softens or changes into a rubbery state at a temperature lower than the molding temperature of the resin. It may be something.

According to the above-described structure, since the non-volatile gas is filled in a predetermined film which softens or changes into a rubbery state at a temperature lower than the molding temperature of the resin, the filling material is used. The material can be increased and decreased in volume by a change in temperature, ensuring the reusability of the filling material, making the resin molding method and the resin molding die more inexpensive, and having a higher transfer accuracy. It can be good.

Further, for example, at least one of the cavity pieces not having the transfer surface has a volume of the cavity in accordance with a pressure in the cavity filled with the resin. May be arranged so as to be movable by a predetermined amount in the direction in which the image is spread.

According to the above arrangement, at least one of the cavity pieces having no transfer surface is provided so as to be movable by a predetermined amount in a direction of increasing the volume of the cavity in accordance with the pressure in the cavity filled with the resin. By moving the cavity piece, it is possible to prevent the pressure inside the cavity from being excessive due to the filling material, and to prevent unnecessary distortion from occurring in the resin molded product. It can be further improved.

Further, for example, as described in claim 15, the cavity piece is moved by a hydraulic cylinder or the like which is attached to the mold for movement and disposed outside the mold. There may be.

According to the above configuration, since the cavity piece is moved by the hydraulic cylinder or the like which is provided outside the mold while being attached to the mold, the pressure in the cavity becomes excessive due to the filling material. By moving the cavity piece inexpensively, it is possible to prevent unnecessary distortion from occurring in the resin molded product at a low cost, and the resin molding method and the resin molding die are further reduced in cost. In addition, the molding quality can be further improved.

Further, for example, the cavity piece may be moved by a pressure generated by the filling material in the cavity.

According to the above construction, since the cavity piece is moved by the pressure generated by the filling material in the cavity, the excessive pressure in the cavity due to the filling material is prevented by moving the cavity piece at low cost. Then, it is possible to inexpensively prevent the occurrence of unnecessary distortion in the resin molded product, and to use a resin molding method and a resin molding die that are more inexpensive and have better molding quality. It can be.

Further, for example, as set forth in claim 17, at least one of the cavity pieces not having the transfer surface is provided between a cavity plate provided on the back surface of the cavity piece and the cavity piece. A predetermined elastic body may be provided, and the elastic body may be arranged so as to be movable in a direction of expanding the volume of the cavity by pressing the elastic body by a pressure generated by the filling substance in the cavity.

According to the above arrangement, at least one of the cavity pieces having no transfer surface is provided with a predetermined elastic body between the cavity plate and the cavity piece provided on the back surface of the cavity piece, Since the elastic body is pressed by the pressure generated by the filling material in the cavity, it is arranged so as to be movable in the direction of expanding the volume of the cavity,
Excessive pressure in the cavity due to the filling material can be prevented by moving the cavity piece inexpensively, and unnecessary distortion can be prevented from occurring in the resin molded product at low cost. In addition, the resin molding die can be made more inexpensive and have better molding quality.

[0061]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIG. 1 to FIG. 6 are views showing a first embodiment of the resin molding method and the resin molding die of the present invention.

FIG. 1 is a front sectional view of an injection molding die 1 to which the first embodiment of the resin molding method and the resin molding die of the present invention is applied, and FIG. FIG. 2 is a side sectional view of the molding die 1.

In FIGS. 1 and 2, the injection mold 1
Has a pair of dies 2 and dies 3, and the lower dies 2 and the upper dies 3 are arranged so that at least one of them can move away from the other. The lower mold 2 has cavity pieces 4 and 5 having no transfer surface, and also has a cavity piece 6, and the cavity piece 6 has a transfer surface 6a. The upper mold 3 includes a cavity piece 7, on which a transfer surface 7 a is formed. In the injection molding die 1, a cavity 8 is defined by the dies 2, 3, the cavity piece 4, the cavity piece 5, the transfer surface 6a of the cavity piece 6, and the transfer surface 7a of the cavity piece 7.

As shown in FIG. 1, the cavity piece 5 has a resin introduction path 10 for introducing the resin 9 (see FIGS. 3 and 4) into the cavity 8.

As shown in FIG. 2, a filling substance introduction passage 11 is formed in the cavity piece 4, and at least an end of the filling substance introduction passage 11 on the cavity 8 side has a diameter of 0.1 mm or less. It is formed in the size of.

The filling substance introduction path 11 is provided in the injection mold 1.
Filling material 1 such as liquid or gaseous foaming agent, foaming gas, or non-volatile gas is placed in cavity 8 from outside.
2 (see FIG. 4) is introduced.

Next, the operation of the present embodiment will be described. In the injection molding die 1, a cavity 8 is defined by the dies 2, 3, the cavity piece 4, the cavity piece 5, the transfer surface 6a of the cavity piece 6, and the transfer surface 7a of the cavity piece 7. To mold a plastic molded product using the mold 1, first, the dies 2, 3, the cavity piece 4, the cavity piece 5, the cavity piece 6, and the cavity piece 7 are heated to a temperature lower than the softening temperature of the resin 9. As shown in FIGS. 3 and 4, the molten resin 9 heated to a softening temperature or higher is injected and filled into the cavity 8 from the resin introduction path 10. This resin 9 may be either a thermoplastic resin or a thermosetting resin.

Next, a resin pressure is generated on the transfer surface 6a of the transfer piece 6 and the transfer surface 7a of the transfer piece 7 to bring the resin 9 into close contact with the transfer surfaces 6a, 7a. Cooling.

At this time, as shown in FIG. 4, a predetermined amount of the filling material 12 is supplied through the filling material introduction path 11 to the surface of the cavity piece 4 having no transfer surface on the cavity 8 side (the transfer surface 6a and the transfer surface 6a). It is introduced between a part or all of the surface (other than the surface 7 a) and the resin 9 in the cavity 8. When the filling substance 12 is introduced between the cavity piece 4 and the resin 9,
The portion of the resin 9 in contact with the filling material 12 is more easily moved than the other portions, and the shrinkage of the resin 9 caused by cooling is reduced by the filling material 12 and the portion of the resin 9 facing (contacting) the filling material 12. Move, absorb, transfer surface 6 of resin 9
a and the portion facing the transfer surface 7a can be prevented from sinking.

That is, the cavity 9 is filled with the resin 9 by injection filling to generate an internal pressure of the resin 9, and thereafter, a skin layer for solidifying a surface layer portion of the resin 9 in contact with the inner surface of the cavity 8 is formed. . In this state, a distribution of a temperature difference of the resin 9 occurs due to a difference in cooling rate between a thin portion and a thick portion of the resin 9, and a distribution of an internal pressure difference of the resin 9 due to the distribution of the temperature difference or injection filling. The distribution of the internal pressure difference of the resin 9 due to the difference in the amount of heat generated by shearing at the time exists.

Thereafter, as described above, the filling substance introduction path 1
1, a predetermined amount of the filling material 12 is introduced between a part or all of the cavity 8 side surface of the cavity piece 4 having no transfer surface and the resin 9 in the cavity 8. The contact with the cavity piece 4 is cut off by the filling substance 12, and the thermal conductivity of the portion of the resin 9 facing the filling substance 12 is reduced.

When the resin 9 is cooled in this state, the resin 9
The cooling rate of the portion facing the filling substance 12 of the resin 9
The cooling rate of the other parts is lower than that of the other parts. The part of the resin 9 facing the filling material 12 absorbs the shrinkage of the resin 9 by the cooling, and the distortion generated inside the resin 9 is reduced. 9
Is concentrated on the portion facing the filling substance 12 of the above. Further, the filling material 12 presses the portion of the resin 9 facing the filling material 12, so that the resin 9 is transferred to the transfer surface 6a and the transfer surface 7a.
a, and transfer accuracy can be improved.

Then, as shown in FIGS. 5 and 6, at least one of the dies 2 and 3, for example, the lower die 2 is moved downward, and the cavity pieces 4 and 5 are moved in the opening direction. Then, the resin 9 of the molded product is taken out.

As described above, according to this embodiment, at least one or more cavities are formed by at least one or more cavity pieces having a transfer surface and at least one or more cavity pieces having no transfer surface. Using a pair of defined molds, filling the cavity with molten resin heated to a temperature equal to or higher than the softening temperature, transferring the transfer surface to the resin, and cooling the resin to a temperature lower than the softening temperature. A predetermined filling substance 12 is interposed between at least one cavity piece 4 among the cavity pieces 4 and 5 not having the resin and the resin 9.
, And sinks generated in the resin 9 at the time of cooling can be absorbed by a portion of the resin 9 in contact with the filling material 12. Therefore, the resin 9 is transferred to the transfer surface 6a with the filling material 12,
7a can be pressed more appropriately,
The resin 9 and the cavity piece 4 are separated from each other by the filling substance 12, the cooling rate of the portion of the resin 9 in contact with the filling substance 12 is made slower than that of the other parts, and the shrinkage of other parts of the resin 9 is reduced by the resin 9. Can be absorbed at the portion in contact with the filling material 12, and the sink of the resin molded article 9 can be prevented, and the transfer accuracy can be improved.

FIG. 7 is a view showing a second embodiment of the resin molding method and the resin molding die according to the present invention.

FIG. 7 is a side sectional view of an injection molding die 20 to which the second embodiment of the resin molding method and the resin molding die of the present invention is applied.

In this embodiment, an evaporative foaming agent is used as a filling material in the injection molding die 1 of the first embodiment, and the evaporative foaming agent is supplied by a foam vaporizer outside the mold. In the description of this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. .

In FIG. 7, an injection mold 20 has a foaming agent vaporizer 21 disposed outside the molds 2 and 3, and the foaming agent vaporizer and (heating means) 21 A foaming agent vaporizing chamber 21a in which the mold foaming agent 22 is stored and a vaporizing mechanism (not shown) for heating and vaporizing the evaporative foaming agent 22 in the foaming agent vaporizing chamber 21a are provided. This blowing agent vaporizer 2
1 may be any device as long as it can control the temperature suitable for vaporizing the evaporative foaming agent 22 by the vaporizing mechanism.

The blowing agent vaporizing chamber 21a of the blowing agent vaporizing device 21
The gas supply pipe 11 formed in the cavity piece 4 is in communication with the gas introduction pipe 23, and the foaming gas 24 of the evaporative foaming agent 22 vaporized in the foaming agent vaporizing chamber 21 a of the foaming agent vaporizer 21. Is introduced into the cavity 8 through the gas introduction pipe 23 and the filling substance introduction path 11.

The evaporative foaming agent 22 includes aliphatic hydrocarbons such as pentane, neopentane, hexane, isohexane, heptane and isoheptane; aliphatic chlorinated hydrocarbons such as methyl chloride and methyl dichloride; and Freon 11, Freon 12, freon 21, freon 114, freon 1
An aliphatic fluorinated hydrocarbon such as 13 can be used, but the evaporative foaming agent 22 is not limited to these, and any solvent having a low boiling point can be used. .

The injection molding die 20 of the present embodiment passes through the resin introduction path 10 (not shown in FIG.
Is filled in the cavity 8 and then cooled and solidified, the evaporating foaming agent 22 is vaporized in the foaming agent vaporizing chamber 21a of the foaming agent vaporizer 21 and the generated foaming gas 24 is supplied to the gas introduction pipe 23 and the cavity piece. 4 through the filling material introduction path 11 between the resin 9 in the cavity 8 and part or all of the surface of the cavity piece 4 having no transfer surface on the cavity 8 side. The foamed gas 24 introduced between a part or all of the surface of the cavity piece 4 having no transfer surface on the cavity 8 side and the resin 9 in the cavity 8 is filled with the resin 9 filled in the cavity 8. The corresponding cavity piece 4
Is pressed, the contact between the resin 9 and the cavity piece 4 is cut off by the foaming gas 24, and the thermal conductivity of the portion of the resin 9 facing the foaming gas 24 is reduced.

When the resin 9 is cooled in this state, the resin 9
The cooling rate of the portion facing the foam gas 24 of the resin 9
The portion of the resin 9 facing the foam gas 24 preferentially absorbs the shrinkage of the resin 9 due to cooling, and the strain generated inside the resin 9 is reduced. 9
Is concentrated on the portion facing the foam gas 24. Further, the foaming gas 24 presses the portion of the resin 9 facing the foaming gas 24, so that the resin 9 is transferred to the transfer surface 6a and the transfer surface 7a.
a, and transfer accuracy can be improved.

Then, at least one of the molds 2 and 3, for example, the lower mold 2 is moved downward, and the cavity pieces 4 and 5 are moved in the opening direction, so that the resin 9 of the molded product is moved.
Take out.

Since at least the end of the filling substance introduction passage 11 on the side of the cavity 8 is formed to have a diameter of 0.1 mm or less, the molten resin 9 injected and filled into the cavity 8 is filled. It is possible to prevent the substance introduction passage 11 from being blocked.

As described above, according to the present embodiment, the filling material introducing passage, which is a filling material introducing passage for communicating the inside of the cavity 8 with the outside of the molds 2 and 3, to the cavity piece 4 having no transfer surface. A passage 11 is formed, and the evaporative foaming agent 22 is used as a filling substance.
It is heated and evaporated by a foaming agent vaporizer 21 which is a heating means provided outside, and the foaming agent vaporizer 2
1 through the gas introduction pipe 23 and the filling substance introduction path 11, the gas is introduced between the cavity piece 4 having no transfer surface in the cavity 8 and the resin 9. Therefore, the foaming gas 24 can be supplied into the cavity 8 at a free timing and in a free amount while simplifying the mold structure, and the molding of the resin 9 can be performed at low cost, and the transfer accuracy can be improved. Can be improved.

FIG. 8 is a view showing a third embodiment of the resin molding method and the resin molding die according to the present invention.

FIG. 8 is a side sectional view of an injection molding die 30 to which the third embodiment of the resin molding method and the resin molding die according to the present invention is applied.

In the present embodiment, a liquid evaporating foaming agent is used as the filling material in the injection molding die 1 of the first embodiment, and the injection molding die 1 is formed by a pressure applying device outside the die. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Is omitted.

In FIG. 8, the injection molding die 30 is provided with a pressure applying device 31 outside the mold 2 and the mold 3, and the pressure applying device (pressurizing means) 31 is provided in a liquid state. A pressure chamber 31a in which the evaporative foaming agent 32 is stored and a pressure applying mechanism (not shown) for applying pressure to the liquid evaporative foaming agent 32 in the pressure chamber 31a are provided. This pressure applying device 31
May be any as long as pressure control suitable for applying appropriate pressure to the liquid evaporative foaming agent 32 is possible.

The pressure chamber 31a of the pressure applying device 31 and the filling substance introduction path 11 formed in the cavity piece 4 are communicated by a liquid introduction pipe 33, and the liquid vaporized in the pressure chamber 31a of the pressure applying device 31. The evaporative foaming agent 32 is introduced into the cavity 8 through the liquid introduction pipe 33 and the filling substance introduction path 11.

The injection molding die 30 of the present embodiment passes through the resin introduction passage 10 (not shown in FIG.
Is filled in the cavity 8 and then cooled and solidified, the liquid evaporating foaming agent 32 in the pressure chamber 31a of the pressure applying device 31 is applied with pressure by the pressure applying device 31 to thereby form a liquid introduction pipe. 33 and the cavity piece 4 having no transfer surface through the filling material introduction path 11 of the cavity piece 4.
Part or all of the surface of the cavity 8 on the side of the cavity 8
And between the resin 9 inside. The liquid evaporative foaming agent 32 introduced between a part or all of the surface of the cavity piece 4 having no transfer surface on the cavity 8 side and the resin 9 in the cavity 8 is heated at the temperature of the resin 9. After foaming, the portion of the resin 9 filled in the cavity 8 facing the cavity piece 4 is pressed, and the contact between the resin 9 and the cavity piece 4 is cut off by the evaporative foaming agent 32. The thermal conductivity of the portion facing the evaporative foaming agent 32 is reduced.

When the resin 9 is cooled in this state, the resin 9
The cooling rate of the portion of the resin 9 facing the evaporative foaming agent 32 becomes slower than the cooling speed of the other portions of the resin 9, and the resin 9 shrinks by cooling to face the evaporative foaming agent 32. The part which absorbs preferentially absorbs and concentrates the strain generated inside the resin 9 on the part of the resin 9 facing the evaporative foaming agent 32. Further, since the evaporative foaming agent 32 presses the portion of the resin 9 facing the evaporative foaming agent 32, the resin 9 can be pressed against the transfer surface 6a and the transfer surface 7a, and the transfer accuracy is improved. Can be done.

Then, at least one of the dies 2 and 3, for example, the lower die 2 is moved downward, and the cavity pieces 4 and 5 are moved in the opening direction so that the resin 9 of the molded product is moved.
Take out.

Since at least the end of the filling substance introduction passage 11 on the side of the cavity 8 is formed to have a diameter of 0.1 mm or less, the cavity 8 is filled with the molten resin 9 injected and filled. It is possible to prevent the substance introduction passage 11 from being blocked.

As described above, according to the present embodiment, the filling material introduction path 11 for communicating the inside of the cavity 8 with the outside of the molds 2 and 3 is formed in the cavity piece 4 having no transfer surface. A liquid evaporative foaming agent 32 is used as a filling substance, and the liquid evaporative foaming agent 32 is supplied from a pressure applying device 31 which is a pressurizing means provided outside the dies 2 and 3 to a liquid introduction pipe. 33 and the filling substance introduction channel 11, the cavity 8
It is introduced between the cavity piece 4 having no transfer surface and the resin 9 and reacts with the temperature of the molten resin 9 to generate a foaming gas. Therefore, the evaporating foaming agent 32 can be introduced into the cavity 8 at a free timing and in a free amount without using a heat source, and the molding of the resin 9 can be performed at lower cost, and the transfer accuracy can be improved. Can be further improved.

In the case of the second embodiment shown in FIG. 7 and the third embodiment shown in FIG. 8, a reactive foaming agent may be used instead of the evaporative foaming agent.

In this case, the blowing agent vaporizer 2 shown in FIG.
It is not necessary to use a device having a temperature control mechanism and a pressure control mechanism like the pressure applying device 31 shown in FIG. 1 or FIG. By providing only the introduction pipe connecting the filling substance introduction path 11 that has been described, the same effect as that of the second and third embodiments can be obtained with a simpler configuration and at a lower cost. Can be obtained.

In this case, as the reactive foaming agent, a reactive foaming agent which generates carbon dioxide (CO ₂ ) by the reaction of water or the like utilizing the activity of the sissocyanate group, or CO ₂ , N ₂ , A reactive foaming agent that generates an inert gas at normal temperature and normal pressure, such as H ₂ O (g), can be used.

FIG. 9 is a view showing a fourth embodiment of the resin molding method and the resin molding die according to the present invention.

FIG. 9 is a side sectional view of an injection molding die 40 to which the fourth embodiment of the resin molding method and the resin molding die of the present invention is applied.

In this embodiment, a decomposable foaming agent is used as a filling material, and after the decomposable foaming agent is installed in a cavity of a mold, a resin is filled in the cavity.

In FIG. 9, an injection mold 40 includes a pair of dies 41, 42, cavity pieces 43, 44, 45, a cavity piece 46, and the like.
Nos. 4 and 45 have no transfer surface,
6 has a transfer surface 46a. Injection mold 40
Are cavity pieces 43, 44, 4 having no transfer surface.
A cavity 47 is defined by a cavity piece 46 having a transfer surface 5 and a transfer surface 46 a, and a resin introduction path (not shown) for injecting a resin 48 into the cavity 47 is formed in the injection mold 40. . Note that the injection material mold 40 is not formed with the filling material introduction path as shown in FIGS. 7 and 8.

The injection molding die 40 according to the present embodiment includes the transfer surface 4 of the cavity pieces 43 to 46 facing the cavity 47 before the resin 48 is injected into the cavity 47.
The decomposition foaming agent 49 is arranged on an appropriate surface of the cavity pieces 43 to 45 not provided with 6a, for example, as shown in FIG. The installation of the resin 48 in the cavity 47 is performed by using the cavity pieces 43 and 44 for installing the resin 48.
A concave portion or the like for installation is formed on the surface of
8 or a cavity piece 43,
44 may be installed without forming a concave portion or the like, or by adhering to the formed concave portion with a predetermined adhesive or the like.

Examples of the decomposable foaming agent 49 include sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, ammonium nitrite, azide compounds (CaN ₆ , BaN ₆ ),
Uses inorganic blowing agents such as sodium borate, benzene, p-toluenesulfonylhydrazine and the like, and high-temperature blowing agents such as trihydrazinotriazine, p, p-oxybisbenzenesulfonyl semicarbazide and barium azodicarboxylate. Other than these, any decomposable foaming agent that chemically decomposes when heated can be used. In order to make the decomposition temperature of the decomposable foaming agent 49 compatible with the melting temperature of the resin 48, foaming aids such as urea, borax, ethanolamine, zinc oxide, and carbonate may be used. Can also be added.

Before injection of the resin 48 into the cavity 47, the injection mold 40 according to the present embodiment includes the transfer surface 4 of the cavity pieces 43 to 46 facing the cavity 47.
The decomposition type foaming agent 49 is arranged on an appropriate surface of the cavity pieces 43 to 45 not provided with 6a, for example, as shown in FIG. A molten resin 48 is injected into the cavity 47 from a resin introduction path (not shown).

When the molten resin 48 is supplied into the cavity 47, the heat of the molten resin 48 is transmitted to the cavity piece 43 and the decomposition-type foaming agent 49 previously set on the surface of the cavity piece 44 facing the cavity 47. , Decomposition type blowing agent 49
Decomposes to generate foaming gas.

Next, the resin 48 is cooled from the melting temperature to a temperature lower than the softening temperature. At this time, the foaming gas generated by the decomposition of the decomposable foaming agent 49 causes the surfaces of the cavity pieces 43 and 44 to be in contact with the resin 48. Between the cavity piece 43 and the cavity piece 44, which is not the transfer surface of the resin 48, and presses a surface of the cavity piece 43 facing the cavity 47, and heat conduction to the cavity piece 43 and the cavity piece 44 of the surface. Decrease rate.

Therefore, the resin 48 can be appropriately pressed against the transfer surface 46a of the cavity piece 46 with a simpler structure, and the transfer accuracy of the transfer surface 46a can be improved at a lower cost.

In the above embodiment, the case where the present invention is applied to the injection molding die 40 has been described. However, the injection compression molding die, the transfer molding die, and the casting. Mold and R
The present invention can be similarly applied to an IM (reaction injection molding: reactive injection molding) mold and the like.

The decomposition-type foaming agent 49 may be covered with a predetermined coating 50 as shown in FIG. 10, or may be mixed with a predetermined carrier 51 as shown in FIG. It may be solidified while being covered with 51.

When the coating 50 and the carrier 51 are formed of a material that melts at the foaming temperature of the decomposable foaming agent 49, they are set in the cavity pieces 43 and 44 having no transfer surface in the cavity 47, When the molten resin 48 is injected into the inside, the coating 50 and the carrier 51 are melted at the foaming temperature of the decomposable foaming agent 49, and the decomposable foaming agent 49 is foamed. A gap is formed between the portion facing 44 and a part and all of the cavity piece 43 and the cavity piece 44, and the resin 49 is pressed. Therefore, the handleability of the decomposable foaming agent 49 can be improved, sink marks can be absorbed, the molding quality can be improved, and the transfer accuracy can be improved.

The coating 50 and the carrier 51 may be formed of a material which becomes soft or rubbery at the foaming temperature of the decomposition type foaming agent 49. In this case, when the cavity piece 43 and the cavity piece 44 having no transfer surface in the cavity 47 are installed and the molten resin 48 is injected into the cavity 47,
At the foaming temperature of the decomposable foaming agent 49, the coating 50 and the carrier 51 become soft or rubber-like, and the decomposable foaming agent 49 foams and faces the cavity pieces 43 and 44 of the resin 49 in the same manner as described above. Part and cavity piece 43
A gap is formed between the cavity piece 44 and part and all of the cavity piece 44, and the resin 49 is pressed. Therefore, the handleability of the decomposable foaming agent 49 can be improved, sink marks can be absorbed, the molding quality can be improved, and the transfer accuracy can be improved. Further, when the decomposition type foaming agent 49 is decomposed and foamed, the decomposition type foaming agent 4
9 is covered with the rubbery or softened coating 50 or the carrier 51, the foamed gas does not directly contact the resin 49, the resin molded product can be kept normal, and the foamed gas can be kept in the cavity 47. Since it does not directly contact the inner surface of the cavity 47, corrosion of the cavity 47 can be prevented.

Further, the decomposable foaming agent 49 is covered with a predetermined coating 50 or mixed with a predetermined carrier 51 to be solidified, and has at least one projection for installation on the cavity pieces 43, 44 and the like. You may. For example, as shown in FIG.
And one or more projections 52 are formed on the coating 50.

In this case, a concave portion is formed in the cavity pieces 43, 44 and the like in which the decomposable foaming agent 49 is installed, and the projection 52 is inserted into the concave portion, and the decomposable foaming agent 49 covered with the coating 50 is installed. In this case, too, the cavity piece 4
Instead of forming recesses on the bases 3, 44, etc., a decomposable foaming agent 49 covered with the coating 50 may be provided by applying an adhesive or the like to the projections 52 and bonding them to the cavity pieces 43, 44, etc. In this way, the decomposable foaming agent 49 can be installed in a state where it is separated from the wall surface of the cavity 47, particularly the surfaces of the cavity pieces 43, 44 and the like.

In FIG. 12, the decomposition type foaming agent 49 is coated with the coating 50.
Although the description has been given of the case where the decomposition foaming agent 49 is dispersed and mixed in the carrier 51, the same can be applied.

Further, in the case of coating with the film 50, the material to be coated is not limited to the decomposition type foaming agent 49. For example, as shown in FIG.
A non-volatile gas harmless to humans or animals, such as nitrogen, argon, or carbon dioxide, may be injected into the coating 50. Also in this case, the projections 52 may be formed on the coating 50, and the coating 50 is made of a material that softens or becomes rubbery at the molding temperature of the resin 48 or lower.

Thus, the non-volatile gas 53
Before filling the cavity 47 with the resin 48,
Cavity piece 43 having no transfer surface in cavity 47
And the cavity piece 44, and then the cavity 4
When the molten resin 48 is injected into the inside 7, the non-volatile gas 53 in the coating 50 rises, and the non-volatile gas 53 pushes the coating 50 to increase the volume. A space is formed between the portion facing the piece 44 and a part and all of the cavity piece 43 and the cavity piece 44, and the resin 49 is pressed. Therefore, the handleability of the decomposable foaming agent 49 can be improved, sink marks can be absorbed, the molding quality can be improved, and the transfer accuracy can be improved. Furthermore, when the temperature decreases, the volume decreases, and again,
It can be used, has high reusability, and can be made even cheaper.

FIG. 14 is a view showing a resin molding method and a resin molding die according to a fifth embodiment of the present invention.

FIG. 14 is a side sectional view of an injection molding die 60 to which the fifth embodiment of the resin molding method and the resin molding die of the present invention is applied.

In the present embodiment, the cavity piece having no transfer surface can be moved in the cavity direction and in the opposite direction.

In FIG. 14, a mold 60 for injection molding comprises:
Molds 61, 62, cavity pieces 63, 64, 65, and cavity pieces 66 are provided.
5 has no transfer surface, but the cavity piece 66
A transfer surface 66a is provided. The injection molding die 60 has a cavity 67 formed by cavity pieces 63, 64, and 65 having no transfer surface and a cavity piece 66 having a transfer surface 66a. However, a resin introduction path for injecting the resin 68 into the cavity 67 is formed. The cavity piece 64 has
The filling material 69 is transferred to the cavity piece 64 of the cavity 67.
Filling material introduction path 70 for injecting into the surface of
The end of the side is formed to have a size of 0.1 mm or less.

On the surface of the cavity piece 63 having no transfer surface on the side opposite to the cavity 67, that is, the surface on the side of the cavity plate (not shown), a predetermined elastic body 71 is arranged between the cavity plate and the cavity plate. Has been established. Therefore, the cavity piece 63 is
When the elastic body 71 contracts, the elastic body 71 moves in a direction to expand the cavity 67 indicated by an arrow in FIG.

In the injection mold 60 of the present embodiment, when the resin 68 is injected into the cavity 67 and the resin 68 is cooled from a melting temperature to a temperature lower than the softening temperature, a predetermined amount is passed through the filling material introduction path 70. The gaseous or liquid filling material (evaporating foaming agent or reactive foaming agent, etc.) 69 is partially or entirely provided on the cavity 67 side of the cavity piece 64 having no transfer surface and inside the cavity 67. Introduced between the resin 68. When the filling material 68 is introduced between the cavity piece 64 and the resin 68, the portion of the resin 68 in contact with the filling material 69 becomes easier to move than other portions, and the contraction of the resin 68 caused by cooling causes the filling material 69 and The portion of the resin 68 facing the filling material 69 moves and absorbs, and the sink of the portion of the resin 68 facing the transfer surface 66a can be prevented. Further, when the pressure in the cavity 67 becomes excessive due to the filling material 69, the elastic body 71 is contracted in accordance with the excessive pressure, and the cavity piece 63 having no transfer surface expands the cavity 67 (FIG. 14). (In the direction indicated by the middle arrow), and unnecessary distortion of the resin 68 can be prevented. As a result, the molding accuracy of the resin molded product can be further improved.

In this embodiment, the elastic member 71 is provided between the cavity piece 63 having no transfer surface and the cavity plate, so that the cavity piece 6
3, the method of moving the cavity piece 63 is not limited to the method of disposing the elastic body 71. For example, the method of disposing the cavity piece 63 attached to the injection mold 60 is provided. The movement may be performed using a hydraulic cylinder or a pneumatic cylinder which is provided. In this way, the cavity piece 63 can be moved without having a special device.

In this embodiment, the cavity piece 63 is moved. However, the cavity piece to be moved is not limited to this, and has little influence on the shape of the molded product. Can be adjusted, and any cavity piece having no transfer surface formed thereon may be used.

Although the invention made by the inventor has been specifically described based on the preferred embodiments, the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the gist of the invention. It goes without saying that it is possible.

[0128]

According to the resin molding method of the present invention, at least one cavity piece having a transfer surface and at least one cavity piece having no transfer surface has at least one cavity piece. Using a pair of molds in which the above cavities are defined, filling the cavities with molten resin heated above the softening temperature, transferring the transfer surface to the resin, and cooling the resin below the softening temperature A predetermined filling material is interposed between at least one or more of the cavity pieces having no transfer surface and the resin, and sinks generated in the resin at the time of cooling are formed at a portion in contact with the filling material of the resin. Because it is absorbed, the resin can be more appropriately pressed against the transfer surface with the filling material, and the resin and the cavity piece are separated by the filling material,
The cooling rate of the portion in contact with the resin filling material is made slower than the other portions, so that the shrinkage of the other portion of the resin can be absorbed by the portion in contact with the resin filling material, and the resin molded product Can prevent the occurrence of sinking,
Transfer accuracy can be improved.

According to the resin molding die of claim 2,
At least one or more cavity pieces having a transfer surface;
At least one or more cavity pieces having no transfer surface, and using a pair of molds in which at least one or more cavities are defined, filling the cavity with a molten resin heated to a softening temperature or higher, When transferring the transfer surface to the resin and cooling the resin to a temperature lower than the softening temperature, a predetermined filling material is interposed between at least one or more cavity pieces having no transfer surface and the resin. Since the sink generated in the resin at the time of cooling is absorbed in a portion in contact with the filling material of the resin, the filling material can more appropriately press the resin on the transfer surface, and the filling material allows the resin and the cavity piece to be pressed. , The cooling rate of the portion in contact with the resin filling material is made slower than the other portion, and the shrinkage of the other portion of the resin is reduced in the portion in contact with the filling material of the resin. In can be absorbed, it is possible to prevent the occurrence of the resin molded article sinkage, thereby improving the transfer accuracy.

According to the resin molding method and the resin molding die of the third aspect, a filling material introduction passage communicating between the inside of the cavity and the outside of the mold is formed in the cavity piece having no transfer surface, Using an evaporating foaming agent as a filling material, the evaporating foaming agent is heated and evaporated by a heating means provided outside the mold, and a gas introduction pipe and a filling substance introduction passage are formed from the heating means as a foaming gas. Through the cavity between the resin and the cavity piece that does not have a transfer surface in the cavity, thus simplifying the mold structure and supplying the foaming gas into the cavity at any time and in a free amount while simplifying the mold structure. Thus, resin molding can be performed at low cost, and transfer accuracy can be improved.

According to the resin molding method and the resin molding die of the fourth aspect, a filling material introduction passage communicating between the inside of the cavity and the outside of the mold is formed in the cavity piece having no transfer surface, A liquid evaporative foaming agent is used as the filling substance, and the liquid evaporative foaming agent is transferred from the pressurizing means provided outside the mold through the liquid introducing pipe and the filling substance introducing passage into the cavity. Since it is introduced between the cavity piece that does not have a surface and the resin and reacts with the temperature of the molten resin to generate a foaming gas, the evaporating foaming agent can be freely used at any time without using a heat source. The amount can be introduced into the cavity, so that the resin can be molded more inexpensively and the transfer accuracy can be further improved.

According to the resin molding method and the resin molding die of the fifth aspect, a filling material introduction passage communicating between the inside of the cavity and the outside of the mold is formed in the cavity piece having no transfer surface, Using a reactive foaming agent as the filling material,
The reaction type foaming agent is caused to react by a reaction means disposed outside the mold, and as a foaming gas, the gas passes through the gas introduction pipe and the filling material introduction passage, and the cavity piece having no transfer surface in the cavity and the resin. Since it is introduced in the middle, the foaming gas can be introduced into the cavity at any time and at any time without using a special device such as a heat source or a pressure source, and the resin can be molded at a lower cost. And the transfer accuracy can be further improved.

According to the resin molding method and the resin molding die of the sixth aspect, at least the end of the filling material introduction passage formed in the cavity piece, which is open to the cavity, is set to 0.1 mm.
Since it is formed to a size of 1 mm or less, it is possible to prevent the resin filled in the cavity from clogging the filling substance introduction passage and to block the filling substance introduction passage, and to provide a resin molding method and a resin molding die. Can be used with good transfer accuracy.

According to the resin molding method and the resin molding die of the seventh aspect, a decomposable foaming agent is used as a filling material, and the transfer surface in the cavity is provided before the resin is filled in the cavity. Since it is arranged on the surface of the cavity piece that is not facing the cavity, it can be applied not only to injection molding and injection compression molding, but also to transfer molding, casting, RIM, etc. It is possible to eliminate the necessity of providing a special device or a filling material introduction passage in the cavity for supplying the resin to the resin molding method and the resin molding die with better utilization and at a lower cost. Good accuracy can be achieved.

According to the resin molding method and the resin molding die of the eighth aspect, since the decomposable foaming agent is covered with the predetermined film, the handling of the decomposable foaming agent can be facilitated. In addition, the resin molding method and the resin molding die can be made more usable, and the transfer accuracy can be made more favorable at a lower cost.

According to the resin molding method and the resin molding die of the ninth aspect, since the decomposition type foaming agent is coated on the carrier in a state of being mixed with the predetermined carrier, the decomposition type foaming agent is formed. Agent can be handled easily,
The resin molding method and the resin molding die can be made more usable, more inexpensive, and more excellent in transfer accuracy.

According to the resin molding method and the resin molding die of the tenth aspect, since the decomposable foaming agent that is melted at a predetermined foaming temperature is used, the decomposable foaming agent is used for the resin. After molding, it can be easily removed from the mold by sticking to the resin molded product, and the resin molding method and the resin molding mold are more usable, more inexpensive, and have better transfer accuracy. It can be.

According to the resin molding method and the resin molding die of the eleventh aspect, as the coating or the carrier for coating the decomposable foaming agent, one that softens or changes into a rubbery state at the foaming temperature of the decomposable foaming agent is used. Since it is used, the handling of the decomposable foaming agent can be facilitated and the usability can be further improved, and the decomposable foaming agent adheres to the resin molded product after the resin is molded. Thus, the resin molding method and the resin molding die can be more easily used, more inexpensive, and have higher transfer accuracy.

According to the resin molding method and the resin molding die of the twelfth aspect, the decomposable foaming agent is mixed with the carrier or the carrier coated with the carrier in a state of being mixed with the carrier. Since at least one or more protrusions of a predetermined size projecting by a predetermined amount are formed, and the protrusions are arranged on the surface of at least one of the cavity pieces having no transfer surface, The divided foaming agent can be reliably held in a state of being separated from the cavity surface, and the resin molding method and the resin molding die are more easily available, and the transfer accuracy is better at a lower cost. Things.

According to the resin molding method and the resin molding die according to the thirteenth aspect, as the filling material, the non-volatile gas is filled in the predetermined film which softens or changes into a rubbery state at a temperature lower than the molding temperature of the resin. Since it is used, the filling material can be made to increase and decrease in volume by a change in temperature, ensuring the reusability of the filling material, the resin molding method and the resin molding die, The transfer cost can be further reduced and the transfer accuracy can be further improved.

According to the resin molding method and the resin molding die of the present invention, at least one of the cavity pieces having no transfer surface is made to have a volume corresponding to the pressure in the cavity filled with the resin. Since it is arranged so as to be movable by a predetermined amount in the direction of spreading, it is possible to prevent the pressure in the cavity from being excessive due to the filling material by moving the cavity piece to generate unnecessary distortion in the resin molded product. Can be prevented, and the molding quality of the resin can be further improved.

According to the resin molding method and the resin molding die according to the fifteenth aspect, the cavity piece is moved by the hydraulic cylinder or the like which is attached to the mold for movement and disposed outside the die. It is possible to prevent the pressure in the cavity from being excessive due to the filling substance by moving the cavity piece inexpensively, and to prevent unnecessary distortion from occurring in the resin molded product at low cost. The method and the resin molding die can be made more inexpensive and have better molding quality.

According to the resin molding method and the resin molding die of the sixteenth aspect, since the cavity piece is moved by the pressure generated by the filling material in the cavity, the pressure in the cavity becomes excessive due to the filling material. By moving the cavity piece inexpensively, it is possible to prevent unnecessary distortion from occurring in the resin molded product at a low cost, and the resin molding method and the resin molding die are further reduced in cost. In addition, the molding quality can be further improved.

According to the resin molding method and the resin molding die according to the seventeenth aspect, at least one of the cavity pieces having no transfer surface is connected to the cavity plate and the cavity piece provided on the back surface of the cavity piece. A predetermined elastic body is disposed between them, and the elastic body is pressed by the pressure generated by the filling material in the cavity, and is arranged so as to be movable in a direction to expand the volume of the cavity. Excessive internal pressure can be prevented by moving the cavity piece inexpensively, and unnecessary distortion can be prevented from occurring in the resin molded product at low cost. Molds are cheaper and
The molding quality can be further improved.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an injection molding die to which a resin molding method and a resin molding die according to a first embodiment of the present invention are applied.

FIG. 2 is a side sectional view of the injection mold of FIG. 1;

FIG. 3 is a front sectional view showing a state where a resin is filled in a cavity of the injection mold of FIG. 1;

FIG. 4 is a side sectional view of the injection mold of FIG. 3;

FIG. 5 is a front sectional view showing a state in which the injection molding die of FIG. 1 is opened and a molded resin product is taken out.

FIG. 6 is a side cross-sectional view of the injection mold of FIG. 5;

FIG. 7 is a side sectional view of an injection molding die to which a resin molding method and a resin molding die according to a second embodiment of the present invention are applied.

FIG. 8 is a side sectional view of an injection molding die to which a third embodiment of the resin molding method and the resin molding die of the present invention is applied.

FIG. 9 is a front sectional view of an injection molding die to which a resin molding method and a resin molding die according to a fourth embodiment of the present invention are applied.

10 is a front sectional view showing a state in which a decomposition type foaming agent applied to the injection mold of FIG. 9 is covered with a film.

11 is a front sectional view showing a state in which a decomposition type foaming agent applied to the injection mold of FIG. 9 is mixed and supported on a carrier.

FIG. 12 is a front sectional view of a state in which a decomposition-type foaming agent applied to the injection mold of FIG. 9 is covered with a film having protrusions.

FIG. 13 is a front sectional view showing a state in which a non-volatile gas is wrapped in a coating having projections as a filling material applied to the injection mold of FIG. 9;

FIG. 14 is a front sectional view of an injection molding die to which a resin molding method and a resin molding die according to a fifth embodiment of the present invention are applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection molding die 2, 3 Mold 4, 5, 6 Cavity piece 6a Transfer surface 7 Cavity piece 7a Transfer surface 8 Cavity 9 Resin 10 Resin introduction path 11 Filling substance introduction path 12 Filling substance 20 Injection molding mold 21 Blowing agent vaporizer 21a Blowing agent vaporizer 22 Evaporating foaming agent 23 Gas introduction tube 24 Bubbling gas 30 Injection molding die 31 Pressure applying device 31a Pressure chamber 32 Evaporation type foaming agent 33 Liquid introduction tube 40 Injection molding die 41 , 42 Mold 43, 44, 45 Cavity piece 46 Cavity piece 46a Transfer surface 47 Cavity 48 Resin 49 Decomposition type foaming agent 50 Coating 51 Carrier 52 Projection 53 Non-volatile gas 60 Injection mold 61, 62 Mold 63, 64 , 65 cavity piece 66 cavity piece 66a transfer surface 67 cavity 68 resin 69 filling material 70 filling Filling material introduction path 71 Elastic body

Claims (17)

[Claims] 1. A pair of molds having at least one cavity defined by at least one cavity piece having a transfer surface and at least one cavity piece having no transfer surface. A resin molding method for transferring the transfer surface to a resin filled in the cavity, wherein the molten resin heated to a softening temperature or higher is filled in the cavity, and the resin generated in the cavity is filled. After the resin is brought into close contact with the transfer surface by pressure to transfer the transfer surface to the resin, when the resin is cooled below the softening temperature, at least one of the cavity pieces having no transfer surface is used. A predetermined filling material is interposed between one or more of the cavity pieces and the resin, and sinks generated in the resin at the time of the cooling are formed with the filling material of the resin. Resin molding method, characterized in that to absorb at a portion. 2. At least one or more cavities are defined by at least one or more cavity pieces having a transfer surface and at least one or more cavity pieces having no transfer surface, and a softening temperature is defined in the cavities. After the molten resin heated above is filled, the resin is brought into close contact with the transfer surface by the resin pressure generated in the cavity, and the transfer surface is transferred to the resin. A resin filling mold, wherein a predetermined filling material is interposed between at least one of the cavity pieces having no transfer surface and the resin, and the cooling is performed. A mold for resin molding, wherein sinks sometimes generated in the resin are absorbed by a portion of the resin in contact with the filling material. 3. The cavity piece having no transfer surface has a filler introduction passage communicating between the inside of the cavity and the outside of the mold, and the filler is an evaporative foaming agent. The transfer surface in the cavity is heated and evaporated by a heating means provided outside the mold, passes through the gas introduction pipe connecting the heating means and the filling substance introduction passage as the foaming gas, and the filling substance introduction passage. 3. The resin molding method according to claim 1, wherein the resin is introduced between the cavity piece having no resin and the resin. 4. The cavity piece having no transfer surface is provided with a filling substance introduction passage communicating between the inside of the cavity and the outside of the mold, and the filling substance is a liquid evaporative foaming agent. Having the transfer surface in the cavity through a liquid introducing pipe connecting the pressurizing means and the filling substance introduction passage by the pressurizing means disposed outside the mold and the filling substance introduction passage. 3. The resin molding method according to claim 1, wherein said resin is introduced between said cavity piece and said resin, and reacts with the temperature of said molten resin to generate a foaming gas. Mold. 5. The cavity piece having no transfer surface is provided with a filler introduction passage communicating between the inside of the cavity and the outside of the mold, and the filler is a reactive foaming agent. The transfer surface in the cavity is reacted as a foaming gas through the gas introduction pipe and the filler introduction passage connecting the reaction means and the filler introduction passage as a foaming gas. 3. The resin molding method according to claim 1, wherein the resin is introduced between the cavity piece not having the resin and the resin. 6. The filling material introduction passage formed in the cavity piece, wherein at least an end opening to the cavity is formed to have a size of 0.1 mm or less. A resin molding method or a resin molding die according to claim 5. 7. The filling material is a decomposable foaming agent, and faces the cavity of the cavity piece having no transfer surface in the cavity before the resin is filled in the cavity. The resin molding method or the resin molding die according to claim 1, wherein the resin molding method is disposed on a surface. 8. The resin molding method or resin molding die according to claim 7, wherein said decomposition type foaming agent is covered with a predetermined film. 9. The resin molding method or resin molding die according to claim 7, wherein the decomposition type foaming agent is coated on the carrier in a state of being mixed with a predetermined carrier. 10. The resin molding method or resin molding die according to claim 7, wherein the decomposition type foaming agent is melted at a predetermined foaming temperature. 11. The method according to claim 8, wherein said coating or said carrier covering said decomposable foaming agent softens or changes into a rubbery state at the foaming temperature of said decomposable foaming agent. A resin molding method or a resin mold according to any one of the above. 12. The filling material covered with the carrier in a state in which the decomposition type foaming agent is mixed with the filling material covered with the coating or the carrier, the protrusion having a predetermined size and projecting by a predetermined amount. 12. The device according to claim 8, wherein at least one or more is formed, and the projection is disposed on a surface of at least one or more of the cavity pieces out of the cavity pieces not having the transfer surface. The resin molding method or resin molding die according to any one of the above. 13. The non-volatile gas is filled in a predetermined coating film which softens or changes into a rubbery state at a temperature lower than a molding temperature of the resin. 2. The resin molding method or resin molding die according to 2. 14. At least one of the cavity pieces having no transfer surface is provided so as to be movable by a predetermined amount in a direction to increase the volume of the cavity in accordance with the pressure in the cavity filled with the resin. The resin molding method or the resin molding die according to any one of claims 1 to 13, wherein: 15. The resin molding method according to claim 14, wherein the cavity piece is moved by a hydraulic cylinder or the like which is attached to the outside of the mold so as to move the mold. Or a mold for resin molding. 16. The resin molding method or resin molding die according to claim 14, wherein said cavity piece is moved by a pressure generated by said filling material in said cavity. 17. At least one of the cavity pieces having no transfer surface is provided with a predetermined elastic body between a cavity plate and a cavity piece provided on a back surface of the cavity piece. By pressing the elastic body by the pressure generated by the filling material in the cavity,
14. The resin molding method or resin molding die according to claim 1, wherein the resin molding method and the resin molding die are arranged so as to be movable in a direction in which the volume of the cavity is increased.