JP2005335237A - Method for producing solid resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a solid resin molding which can suppress troubles such as a sink and a void in a molding process and produce a product of high quality. <P>SOLUTION: The method for producing the solid resin molding whose thickness changes includes a resin piece housing process for housing one of resin pieces 10a-10e in a mold 2 having a molding space corresponding to the shape of the solid resin molding, a resin raw material injection process for injecting a monomer of the same kind of resin as the raw material of the resin pieces 10a-10e, and a curing process in which the monomer is reacted and cured. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a solid resin molded product having a thickness change in the thickness direction.

  Conventionally, for example, there is a resin product obtained by molding a resin material such as acrylic or urethane into a predetermined shape. In manufacturing such a resin product, for example, a resin product may be manufactured by injecting a molten resin material into a sealed molding space by combining molding dies (see, for example, Patent Document 1).

  However, the conventional method for producing a solid resin molded product has the following problems. That is, when trying to produce a solid resin molded product with a large thickness by injection molding as described above, in the process where the injected molten resin raw material is cured, There is a risk that voids in the resin material (bubbles due to gas in the resin material) or the like may occur. In particular, for example, in the case of a transparent body such as a resin lens, sink marks and voids are particularly noticeable. Therefore, it is necessary to suppress these troubles as much as possible.

JP 2004-17627 A

  The present invention has been made in view of the above-mentioned conventional problems, and can provide a method for producing a solid resin molded product that can suppress problems such as sink marks and voids in the molding process and can produce a high-quality product. It is what.

The present invention is a method for producing a solid resin molded product having a thickness change in the thickness direction,
A resin piece containing step of containing one piece or two or more pieces of resin in a mold having a molding space corresponding to the shape of the solid resin molded product;
A resin raw material injection step of injecting a monomer of the same resin as the raw material of the resin piece into the mold,
A solid resin molded product manufacturing method characterized by performing a curing step of reacting and curing the monomer.

  The method for producing a solid resin molded product according to the present invention includes housing a resin piece containing at least one or two or more resin pieces in a mold having a molding space corresponding to the shape of the solid resin molded product. A process, a resin raw material injection process for injecting a monomer of the same resin as the raw material for the resin piece into the mold, and a curing process for reacting and curing the monomer.

  In this method for producing a solid resin molded product, the resin piece is accommodated in the mold in the resin piece accommodation step. Therefore, compared with the volume of the cavity, the amount of the monomer to be injected in the resin raw material injection step can be suppressed. Therefore, compared with the volume of the solid resin molded product to be molded, the volume for curing the monomer in the curing step can be suppressed. Therefore, compared with the case where a solid resin molded product is produced without using the resin piece, the occurrence of sink marks and voids can be remarkably suppressed in the curing step.

  As described above, according to the method for manufacturing a solid resin molded product of the present invention, it is possible to obtain a high-quality product while suppressing troubles in the molding process.

In the present invention, it is preferable that the resin piece accommodation step and the resin raw material injection step are alternately and repeatedly performed, and then the curing step is performed (claim 2).
In this case, the resin piece containing step and the resin raw material injection step are alternately and repeatedly performed, so that the amount of the resin piece charged per time and the amount of the monomer injected per time can be reduced. can do. Thereby, the malfunction which may occur by throwing in the said resin piece in a comparatively large quantity or inject | pouring the said monomer can be suppressed. For example, the mold can be filled with the resin piece and the monomer without leaving air or the like in the molding space.

  In addition, when there is no possibility that a malfunction will arise, it cannot be overemphasized that the said resin piece accommodation process and the said resin raw material injection | pouring process can be performed only once. Furthermore, the resin piece accommodation step may be performed prior to the resin material injection step, or the resin material injection step may be performed prior to the resin piece accommodation step.

  In the resin piece accommodation step, at least a part of the resin piece is one piece or two shaped so as to be along the cavity surface of the mold or the surface of the resin piece already contained in the mold. It is preferable to use one or more substantially plate-like resin pieces (claim 3).

  In this case, if a substantially plate-shaped resin piece is used and the resin piece is accurately laminated in the mold, the gap between the resin pieces laminated adjacent to each other can be further suppressed. In this case, the capacity of the monomer to be cured in the curing step can be further suppressed, and the quality of the solid resin molded product to be manufactured can be further improved.

  In addition, when using the substantially plate-shaped resin piece, the resin piece accommodation and the monomer injection are repeated, so that a single amount is provided in the gap between the adjacent resin pieces. It is preferable to laminate the resin pieces in a mold while filling the body. In this case, the monomer can be easily and reliably disposed between adjacent resin pieces.

Moreover, it is preferable to use the granular resin piece as at least one part of the said resin piece at the said resin piece accommodation process (Claim 4).
In this case, the volume of the resin raw material injected in the resin raw material injection step can be suppressed by accommodating the granular resin pieces in the mold. And by suppressing the volume of the monomer to be cured in the curing step, a high-quality solid resin molded product can be manufactured while suppressing the occurrence of sink marks and voids.

In particular, in the molding space that accommodates the granular resin pieces, voids formed between adjacent resin pieces communicate with each other. Therefore, in the resin raw material injecting step, the monomer can be efficiently poured into a gap excluding the space occupied by the resin piece in the molding space.
Furthermore, since the resin piece is granular, it can be used for various types of molds, the shape of the solid resin molded product can be easily changed, and it can be used for various types of small-scale production. Easy. In addition, as said resin piece, it is also possible to use both the plate-shaped thing mentioned above and a granular thing.

Moreover, it is preferable to implement the immersion swelling process which immerses the said resin piece in the said resin raw material prior to implementation of the said resin piece accommodation process (Claim 5).
In this case, the surface can be swollen by immersing the resin piece in the resin raw material. The swollen surface of the resin piece has good affinity with the monomer injected in the resin raw material injection step in the subsequent step. Therefore, in the manufactured solid resin molded product, the boundary between the resin piece and the portion where the injected monomer is newly cured can be made inconspicuous.

The solid resin molded product is preferably made of acrylic or urethane.
In the case of acrylic or urethane, sinks and the like due to thick molding are likely to occur, and therefore the method for producing a solid resin molded product of the present invention is particularly effective.

Moreover, it is preferable that the said solid resin molded product is transparent (Claim 7).
In this case, the influence of troubles such as sink marks and voids generated in the molding process of the solid resin molded product is easily manifested. Therefore, the effect of the present invention is particularly effective.

(Example 1)
This example is an example relating to a method for manufacturing a solid resin molded product 1 made of acrylic. This content will be described with reference to FIGS.
This example relates to a method of manufacturing a solid resin molded product 1 (FIG. 3) having a thickness change in the thickness direction.
As shown in FIGS. 1 and 2, the method for manufacturing the solid resin molded product 1 includes a single resin piece 10 a to 10 e in a mold 2 having a molding space corresponding to the shape of the solid resin molded product 1. A resin piece containing step for containing any of the above, a resin raw material injecting step for injecting a monomer of the same kind of resin as the raw material of the resin pieces 10a to 10e, and a curing step for reacting and curing the monomer And do.
This content will be described in detail below.

  The solid resin molded product 1 manufactured in this example is a resin block having a thickness change in the thickness direction as shown in FIG. In forming the solid resin molded product 1, a mold 2 (FIG. 1) having a molding space corresponding to the shape of the solid resin molded product 1 is used. The molding die 2 is composed of a combination of an upper die 2b and a lower die 2a which are divided into upper and lower parts, and a molding space corresponding to the shape of the solid resin molded product 1 is formed inside the molding die 2. is there.

Next, the manufacturing method of the solid resin molded product 1 of this example will be described step by step.
In carrying out this manufacturing method, a substantially plate-shaped resin member (hereinafter, appropriately described as resin members 10a to 10e) as the resin pieces 10a to 10e is prepared in advance. The resin member 10a has a substantially plate shape along the molding surface 20a which corresponds to the bottom surface of the lower mold 2a of the molding die 2. In addition, as shown in FIG. 1, the lower mold 2a of the mold 2 of this example has a ridge-like protrusion 21a at a substantially central portion. Therefore, the resin member 10a of this example is provided with a bent portion corresponding to the protruding portion 21a, as shown in FIG. The bent portion may be formed without a gap from the protruding portion 21a, or may be formed with a gap from the protruding portion 21a.

  Further, as shown in FIG. 1, the resin member 10 b is substantially plate-shaped along the surface shape of the resin member 10 a on the upper mold 20 b side. The resin member 10c has a substantially plate shape along the surface shape of the resin member 10b on the upper mold 20b side. The resin member 10d has a substantially plate shape along the surface shape of the resin member 10c on the upper mold 20b side. The resin member 10e has a substantially plate shape that has a surface shape corresponding to the molding surface 20b of the upper mold 2b while being along the surface shape of the resin member 10d on the upper mold 20b side. In this example, these resin members 10a to 10e were produced by injection molding. Each resin member 10a-10e can also be produced by methods other than injection molding, for example, extrusion molding, cutting, or the like.

  And in the manufacturing method of this example, first, the resin piece accommodation process which accommodates the resin members 10a-10e in the lower mold | type 2a, and the 1st resin raw material injection | pouring process which inject | pours a monomer in the lower mold | type 2a are carried out. This was repeated for each resin member 10a to 10e. Then, the 2nd resin raw material injection | pouring process which inject | pours a monomer in the sealing mold 2 was implemented, and as shown in FIG. 2, the hardening process was implemented as shown in FIG. This procedure will be described below.

  First, the resin piece accommodation process which accommodates the resin member 10a in the lower mold | type 2a is implemented. Here, the resin member 10a is accommodated along the molding surface 20a of the lower mold 2a. And the said 1st resin raw material injection | pouring process is implemented, and a monomer is poured in in the lower mold | type 2a which accommodated the resin member 10a. In the first resin material injection step, as shown in FIG. 4, an amount of monomer was poured so that the surface of the resin member 10 a was covered with the monomer 16. In this example, the first resin material injection step was performed in a room temperature environment (approximately 20 degrees).

Next, the resin piece accommodating step is performed again, and the resin member 10b is accommodated in the lower mold 2a. Here, the resin member 10b is accommodated along the surface of the resin member 10a in the lower mold 2a. Then, the first resin raw material injection step is performed, and the monomer is injected into the lower mold 2a containing the resin members 10a and 10b. In the first resin raw material injection step, as shown in FIG. 5, the monomer was poured in such an amount that the surface of the resin member 10 b was covered with the monomer 16.
In this example, the same procedure as that performed for the resin member 10a or 10b is repeated for the resin members 10c to 10e. Thereby, in the lower mold | type 2a, the resin members 10a-10e can be laminated | stacked via a monomer (refer FIG. 1).

  In this example, prior to housing the resin members 10a to 10e in the lower mold 2a, the resin members 10a to 10e are immersed in the same liquid monomer used in the resin raw material injection step. It was. In this example, the immersion of the resin members 10a to 10e was performed for about 24 hours under a room temperature environment (approximately 20 degrees). Thereby, the surface of resin member 10a-10e can be swollen, and the boundary of resin member 10a-10e and the area | region which newly hardened the monomer by the said hardening process in the produced solid resin molded product 1 Can be made inconspicuous.

  After that, as shown in FIG. 2, the lower mold 2a and the upper mold 2b are combined to seal the molding space. Then, in this state, the second resin material injection step for injecting the monomer into the gap in the mold 2 is performed. Thereby, the molding space formed in the mold 2 was filled with the resin members 10a to 10e which are resin pieces and the monomer. In this example, the second resin material injection step was performed under a room temperature environment (approximately 20 degrees).

  Thereafter, the pressure inside the mold 2 is reduced with the cavity sealed. In this example, a vacuum apparatus (not shown) was used, and the above-mentioned pressure reduction was performed by communicating the suction pipe with the cavity. In this way, by reducing the pressure inside the mold 2, bubbles contained in the liquid monomer, mixed gas, etc. can be excluded, and bubbles are generated inside the solid resin molded product 1 to be produced. The risk of doing this is suppressed.

  Next, a curing step for reacting and curing the monomer in the mold 2 is performed. In this example, prior to carrying out the curing step, the mold 2 was filled with nitrogen gas. By filling the nitrogen gas, it is possible to prevent the monomer from being exposed to oxygen, water, or the like in the air and to suppress the generation of bubbles.

  In the curing step, the mold 2 was left in a room temperature environment (approximately 20 degrees) to react and cure the monomer. In this example, the above-described curing step was performed while reducing the pressure inside the mold 2 (reduced pressure to about 10 kPa) so that bubbles generated with the reaction of the monomer can be discharged. In place of this, the above curing step is performed while pressurizing the inside of the mold 2 at about 1.0 MPa to 1.5 MPa so that the generation of bubbles accompanying the reaction of the monomer can be suppressed. You can also.

  In this example, after a certain period of time, the cured solid resin molded product 1 (FIG. 2) was taken out from the mold 2. In addition, although this fixed time is based also on the compounding quantity of the hardening | curing agent mix | blended in a monomer, in this example, it was 3 hours. This fixed time is preferably set according to the shape of the hollow resin molded product 1 to be manufactured, the number of laminated resin members 10a to 10e laminated in the mold 2, and the like. Furthermore, when the reaction of the monomer in the curing step is insufficient, after curing from the mold 2, for example, post-cure (at a temperature of 80 ° C. for about 60 minutes) is performed using an oven. Also good.

(Example 2)
This example is an example in which the granular resin piece 11 is changed based on the first embodiment. This will be described with reference to FIG.
In the resin piece accommodation step in the manufacturing method of the solid resin molded product 1 of this example, a large number of resin pieces 11 are collectively accommodated in the mold 2. And the resin raw material injection | pouring process is implemented in the state which sealed the shaping | molding space, and the monomer 16 is inject | poured in the shaping | molding die 2. FIG. That is, in this example, unlike the first example, the resin raw material injection step is performed only once.
Then, the hardening process which hardens | cures a monomer was implemented by the procedure similar to Example 1. FIG.

Other configurations and operational effects are the same as those in the first embodiment.
Furthermore, in the manufacturing method of the solid resin molded product 1 of this example, for example, it may be effective to accommodate the resin piece 11 in the mold 2 without swelling the surface. For example, if each resin piece 11 is formed in a predetermined shape, the outline of the resin piece 11 having the predetermined shape can be positively revealed in the manufactured solid resin molded product 1.

  Moreover, as the shape of the resin piece 11, for example, when the resin pieces 11 having various sizes are combined, the total volume of the gap excluding the resin piece 11 in the cavity can be suppressed. In this case, the volume of the monomer reacted in the curing step can be suppressed, and the workability of the curing step can be further improved.

Sectional drawing which shows a mode that the resin piece (resin member) was laminated | stacked within the shaping | molding die in Example 1. FIG. Sectional drawing which shows the solid resin molded product shape | molded in the shaping | molding die in Example 1. FIG. Sectional drawing which shows the solid resin molded product in Example 1. FIG. Sectional drawing which shows the state which accommodated the resin piece in the lower mold | type in Example 1. FIG. Sectional drawing which shows the state which accommodated the resin piece in the lower mold | type in Example 1. FIG. Sectional drawing which shows the production process of the solid resin molded product in Example 2. FIG.

Explanation of symbols

1 Solid resin molded product 10a-e Resin piece (resin member)
11 Resin member 16 Monomer 2 Mold 2a Lower mold 2b Upper mold

Claims (7)

A method for producing a solid resin molded product having a thickness change in the thickness direction,
A resin piece containing step of containing one piece or two or more pieces of resin in a mold having a molding space corresponding to the shape of the solid resin molded product;
A resin raw material injection step of injecting a monomer of the same resin as the raw material of the resin piece into the mold,
A method for producing a solid resin molded article, comprising performing a curing step of reacting and curing the monomer.   2. The method for producing a solid resin molded product according to claim 1, wherein the resin piece accommodation step and the resin raw material injection step are alternately and repeatedly performed, and then the curing step is performed.   3. The resin piece accommodation step according to claim 1 or 2, wherein at least part of the resin piece is molded along the cavity surface of the mold or the surface of the resin piece already contained in the mold. A method for producing a solid resin molded product, wherein one or two or more substantially plate-like resin pieces are used.   The method for producing a solid resin molded product according to any one of claims 1 to 3, wherein in the resin piece housing step, a granular resin piece is used as at least a part of the resin piece.   The solid resin molding according to any one of claims 1 to 4, wherein an immersion swelling step of immersing the resin piece in the resin raw material is performed prior to the resin piece accommodation step. Product manufacturing method.   The method for producing a solid resin molded product according to any one of claims 1 to 5, wherein the solid resin molded product is made of acrylic or urethane.   The method for producing a solid resin molded product according to any one of claims 1 to 6, wherein the solid resin molded product is transparent.

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