JPH0539917U - Clamp structure of resin mold - Google Patents

Abstract

(57) [Abstract] [Purpose] A resin molding die is made of different materials and has a clamp structure that absorbs the difference in thermal expansion. By
The time required for curing the resin material is shortened to improve the production efficiency. [Structure] One side of a resin molding die is formed of a metal plate and the other side is formed of a resin plate, and a form frame is interposed between both plate materials at the peripheral edge, and both plate materials are individually formed. Attached to. Then, a flow path for a heat medium such as hot water is formed between both plate materials. [Operation] A heat medium such as hot water uniformly transfers heat to the entire surface of the molding die. Moreover, since the mold material is a thin plate, it has excellent thermal conductivity. As a result, the curing time of the resin material can be greatly shortened. Although the metal plate and the resin plate of the mold material have different thermal expansion coefficients, the difference is absorbed by the mold and the mold itself is not deformed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention uses a metal plate on one side of a mold and a resin plate on the other side of the mold to form a fluid flow path between them, and a clamp structure between the metal plate and the resin plate of a resin molding mold. Related to.

[0002]

[Prior Art]

 For example, in the case of manufacturing a resin molded product having a very large cross-section wall thickness such as a bathtub, it is usual to use upper and lower molds for male and female fitting. This is to improve the shape accuracy of the product by holding the resin raw material with the upper mold and the lower mold until the resin raw material is sufficiently cured.

The conventional upper and lower molds are roughly classified into a resin mold (FRP type) 1 shown in FIG. 10, an electric mold 2 shown in FIG. 11, and a mold 3 shown in FIG. It should be noted that each of the drawings partially shows one of the upper and lower molds. The resin mold 1 is formed by forming a back-up material 4 with an unsaturated polyester resin reinforced by fibers such as glass, coating the surface of the same with an unsaturated polyester resin to form a surface material 5, and molding the mold. There is. In molding a resin product, the upper mold and the lower mold are matched with each other, a resin raw material is poured into a molding space between the two, and the resin is cured to obtain a molded product. In the natural curing, however, it takes a considerable amount of time to cure to such an extent that the shape retention property is not lost even after demolding, and there is a drawback that productivity is poor. Therefore, in this conventional resin mold 1, the temperature of the external atmosphere is raised and heat is applied to the resin raw material by utilizing the heat conduction of the resin mold 1 to cure the resin raw material.

In the electroforming mold 2, a material in which an epoxy resin and sand are mixed is used as a backup material 6, and a steel pipe is embedded in a meandering shape when the backup material 6 is formed to provide a heat medium passage 7. Then, Cu plating 8 and Ni plating 9 are alternately repeated on the surface side of the backup material 6 to obtain a surface material 10 having a multilayer structure, and a mold is formed. In this electroforming mold 2, a heating medium such as hot water can be circulated into the flow path 7 to heat the resin raw material, and it is possible to cure the resin raw material in a shorter time than the resin mold 1 described above.

On the other hand, the mold 3 is formed by casting a metal material to form the backup material 11, and the backup material 11 is subjected to a boring process to form a flow path 12 for the heat medium. Then, the surface side of the backup material 11 is plated with Cr to form the surface material 13, and the die is molded. Also in the case of this mold 3, since the heat medium can be circulated to the flow path 12 to heat and cure the raw material resin, it is extremely excellent in production efficiency.

[0006]

[Problems to be solved by the device]

 However, in the conventional resin mold 1, as described above, the temperature of the external atmosphere is raised, and the heat conduction of the resin mold 1 is used to heat and cure the resin raw material. Therefore, the heat transfer coefficient is extremely low, and it takes about 60 minutes just to apply the gel coat layer to the molding surface of the resin mold 1 (the surface of the surface material 5) for manufacturing the bath to cure it. Further, it takes more than 2 hours to cure the resin raw material for molding the product, and a long time of 5 hours is required as a whole. Moreover, since the surface material 5 of the resin mold 1 is molded with a resin material such as unsaturated polyester, there is a drawback that the molding surface is easily scratched and the surface quality of the product is adversely affected. Furthermore, the resin mold 1 is subject to a change with time that the dimensions thereof are reduced during repeated heating and cooling. Therefore, there is also a drawback that the life of the resin mold 1 is hundreds of times, which is extremely short.

Further, in the conventional electroforming mold 2, it is necessary to arrange the steel pipe in the backup material 6 in a meandering manner to form the flow path 7 for the heat medium, which requires time and labor for its production. There was a flaw. Moreover, in this electroforming mold 2, since the heat medium in the flow paths 7 arranged at the predetermined intervals serves as a heat source, the heat conduction to the molding surface becomes non-uniform with partial strength and weakness, and resin molding is performed. There was a fatal defect as a resin molded product such as cracking of the product and deterioration of boiling performance. In addition to this, this electroforming mold 2 has a drawback that it requires a lot of labor and a high cost because the surface material 10 must be formed by repeating Cu plating 8 and Ni plating 9. It was.

Furthermore, in the conventional mold 3, since the backup material 11 is a cast product, even a type of bathtub manufacturing type has an extremely heavy weight of 15 tons, which is inconvenient to handle. there were. Further, in order to form the flow path 12 of the heat medium in the backup material 11, it is necessary to perform boring processing, and since it is a heavy material, there is a drawback that it takes time to process it. Moreover, in the case of this mold 3 as well, since the flow paths 12 are arranged at predetermined intervals, as in the case of the electroforming mold 2, cracks are generated in the formed product, or the boiling performance is reduced. There was a drawback to

[0009]

[Means for Solving the Problems]

 SUMMARY OF THE INVENTION The present invention has been made by improving and removing the conventional problem described above, and has a clamp structure in which the front surface side and the back surface side of a mold are formed of different materials to absorb the difference in thermal expansion in the peripheral portion. By doing so, it is intended to provide a resin molding die that can make the entire inside of the die a flow path and dramatically improve the heat transfer efficiency.

Therefore, the means adopted by the present invention to solve the above-mentioned problem is that a mold for resin molding in which a flow path for a heat medium such as hot water is provided inside the mold, In addition to molding with a metal plate, the other side of the mold is molded with a resin plate, and a mold is placed between the metal plate and the resin plate at the peripheral edge of the mold to separate the metal plate and the resin plate. Each of them is individually bolted to the formwork.

[0011]

[Action]

 In the resin molding die of the present invention, one side of the molding die is molded with a metal plate, the other side is molded with a resin plate, and each plate material is individually formed by interposing a mold frame at the peripheral edge of both plate materials. It is fixed to the formwork. As a result, it is possible to absorb the difference in thermal expansion generated in both plate materials, and the entire space between both plate materials can be used as a flow path for a heat medium such as hot water. Therefore, heat can be uniformly and efficiently transferred to the entire molding surface, and it is possible to significantly shorten the curing time of the resin material and prevent cracks from occurring.

[0012]

【Example】

 Hereinafter, the configuration of the present invention will be described with reference to the drawings based on an embodiment applied to a molding die for molding a bathtub.

1 to 3 show an upper mold 14 for resin molding according to an embodiment of the present invention. FIG. 1 is a cross-sectional plan view of the upper mold 14, and FIG. FIG. 3 is a right side view of the upper mold 14 in a vertical cross section. As shown in the figure, this upper mold 14 is provided with a chamber through which hot water is passed inside the mold, and the whole is divided into eight chambers A to H. Further, each of the chambers A to H is provided with a rib 15 having both a rectifying function and a reinforcing function. The ribs 15 form flow paths 16 in which hot water flows evenly in the chambers A to H.

As shown in FIG. 4, the upper mold 14 is manufactured by integrally forming a rib 15 on a resin plate 17 such as an FRP resin material, and disposing an FRP plate 18 on the rib 15. The flow channel 16 is formed, and finally the FRP resin material 19 is overlaid. As another method of manufacturing the upper mold 14, as shown in FIG. 5, a rib 15 is formed by placing an aluminum frame or the like having an H-shaped cross section on a resin plate 17 made of an FRP resin material or the like, and then, as shown in FIG. Similar to the case shown in FIG. 4, the FRP plate 18 is disposed on the rib 15 to form the flow path 16, and finally the FRP resin material 19 is overlaid.

On the other hand, as shown in FIGS. 6 and 7, the lower mold 20 is divided into three chambers J 1, K, and L in the vertical direction, and in each of the divided chambers, the above-described upper mold 14 is used. Similarly to the above, the rib 15 is provided, and the flow path 16 is formed so that the hot water evenly flows through each chamber. Thus, as shown in FIGS. 6 and 8, the lower mold 20 has one surface (molding surface side) molded with a metal plate 21 such as an aluminum alloy and the other surface side with a resin plate 22 such as FRP. It is molded with. The lower die 20 may be molded in the same manner as the resin plate 17 shown in FIGS. 4 and 5 instead of the metal plate 21. The reason why the molding surface side is molded with the metal plate 21 is that the heat conduction is better than in the case of molding with a resin plate, and it is possible to shorten the curing time of the resin material for manufacturing a molded product. In addition, the surface quality of the molded product should be good because the surface is very dense and is a smooth surface close to a mirror surface. Further, it has many advantages such as a longer life than a mold formed of a resin plate.

Thus, when the lower die 20 is molded with different materials of the metal plate 21 and the resin plate 22 in this way, the thermal expansion coefficient of both materials differs depending on the heat medium such as hot water flowing in the flow path 16. The lower mold 20 itself may be deformed. Therefore, in this embodiment, the clamp structure as shown in FIG. 8 is adopted in order to absorb the difference in thermal expansion between the different materials. That is, a part of the mold 23, which is placed on the conveyor and moves on the production line, is interposed between both the metal plate 21 of the lower mold 20 and the peripheral edge of the resin plate 22. Then, the metal plate 21 and the resin plate 22 are fixed to the frame 23 via seal packings 24 and 25 with separate bolts 26 and 27, respectively. Accordingly, even if there is a difference in thermal expansion between the metal plate 21 and the resin plate 22, since the metal plate 21 and the resin plate 22 are not directly connected and fixed, the difference in thermal expansion between the metal plate 21 and the resin plate 22 is between that of the mold 23. Will be absorbed and relaxed. In FIG. 8, 28 is a mold for attaching the upper mold 14.

Next, a method of manufacturing a bathtub using the upper mold 14 and the lower mold 20 configured as described above will be described with reference to FIG. First, the mold release material 29 is applied to the molding surface of the lower mold 20, and the entire lower mold 20 is preheated at a temperature of 65 ° C. Subsequently, the gel coat material 30 is applied. On the other hand, in the lower mold 14, a mold release material 29 is applied to its molding surface. Then, in this embodiment, these upper and lower molds 14 and 20 are matched with each other and clamped in the manner shown in FIG. 8, and the resin concrete 31 is injected into the molding space formed between the upper and lower molds. There is. This injection can be done at very low pressure. Therefore, it is possible to reduce the thickness of the upper and lower molds 14 and 20.

After injecting the resin concrete 31, hot water (heat medium) of 85 ° C. is injected into each of the divided chambers A to H or J to L of the upper mold 14 and the lower mold 20 and circulated in each chamber. ing. The hot water at 85 ° C. injected into each of the chambers A to H or J to L is rectified so as to flow evenly in each chamber by the rib 15 which also has a reinforcing effect. At this time, in each chamber, the division of each chamber and the formation of the flow paths are performed so that the temperature difference between the inflow side and the outflow side of the hot water is within the range of ± 5 ° C. In other words, consideration is given so that the temperature of the hot water on the outflow side of each room does not fall below 80 ° C. The hot water of 85 ° C. supplied to each chamber is uniformly moved around each chamber by the ribs 15, and heat is exchanged with the molding surface. Moreover, since the heat exchange in this case is performed by using hot water in each chamber of the upper and lower molds 14 and 20, that is, the entire surface of each chamber, that is, the entire molding surface side of the upper and lower molds 14 and 20. A uniform heat exchange will be carried out at. By this heating, the resin concrete 31 poured into the molding space is heated and hardened.

The heating of the resin concrete 31 by the heat exchange with the hot water is carried out by the upper mold 14 through the extremely thin resin plate 13 shown in FIGS. 4 and 5. It is performed by heat conduction, and in the lower die 20, heat conduction is performed through a metal plate 21 which is a single thin plate such as an aluminum alloy. Therefore, the heat transfer efficiency can be remarkably improved as compared with the conventional type shown in FIGS. 10 to 12, and the curing time of the resin concrete 31 can be greatly shortened.

By the way, when the resin concrete 31 begins to harden due to the heating, the resin concrete 31 itself also exhibits a heat generating action. In this case, when the temperature rises, for example, above 100 ° C., the thermal expansion and contraction becomes large, and there is a manufacturing problem that cracks occur. However, in the upper and lower molds 14 and 20 of the present embodiment which are heated by the hot water of 85 ° C., on the contrary, when the resin concrete 31 becomes too hot, it has the effect of cooling it. Therefore, in the upper and lower molds 14 and 20 of this embodiment, it is possible to prevent the generation of cracks due to the heat generated by the resin concrete 31 itself.

After the resin concrete 31 is hardened by heat exchange with warm water, the upper and lower molds 14 and 20 are demolded and the molded product is taken out. Then, a back-up material 32 such as FRP is provided on the back surface side by spray coating or the like. Next, this may be placed in a curing oven and heated at, for example, 40 ° C. to cure the backup material 32.

As described above, by using the upper and lower molds 14 and 20 and heating the resin material that is the main resin molded product with the hot water flowing through the molds, conventionally, it takes 5 hours to mold one bath. However, in this embodiment, the bath 33 can be formed in 1 hour and 30 minutes.

By the way, the present invention is not limited to the above-described embodiments, but can be appropriately modified. For example, the case where the backup material 32 such as FRP is formed by laying up on the back surface side of the molded product taken out from the upper and lower molds 14 and 20 by spray coating or the like has been described. It is also possible to form. On the other hand, in the lower mold 20, a glass mat may be arranged on the gel coat material 30 and a transparent FRP layer may be formed between the gel coat material 30 and the resin concrete 31. It is possible. The present invention can also be applied to other resin molded products such as wash counters and kitchen counters other than bathtubs. In that case, in each mold, the number of compartments in the chamber, the number of ribs installed, the installation pattern, the flow path pattern, and the like may be set according to the shape and type of the product, the properties of the resin, and the like. Furthermore, the lower surface side (molding surface side) of the upper mold 14 shown in FIGS. 4 and 5 can be molded with a metal plate such as an aluminum material.

[0024]

[Effect of the device]

 As described above, according to the present invention, one side of the resin molding die is molded with a metal plate and the other side is molded with a resin plate, and a mold is interposed between both plate materials at the peripheral edge. Since both plate members are individually attached to the mold, the mold can absorb the difference in thermal expansion between different materials due to the heat medium such as hot water formed between the plate members. Therefore, a mold can be molded using a thin metal plate, and a resin molding mold excellent in heat conduction can be provided. As a result, the time required for thermosetting the resin material can be significantly shortened and excellent production efficiency can be obtained. Further, in the process of curing the resin material, it may generate heat by itself and cause cracks. However, in the resin molding die of the present invention, the hot water flowing in the die also has the effect of cooling the resin material. It is possible to prevent the occurrence of cracks.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of an upper die according to the present invention.

FIG. 2 is a vertical sectional front view of an upper die according to the present invention.

FIG. 3 is a right side view in vertical section of the upper die according to the present invention.

FIG. 4 is a vertical sectional view showing a molding procedure of an upper mold according to the present invention.

FIG. 5 is a vertical cross-sectional view for explaining another forming procedure of the upper mold according to the present invention.

FIG. 6 is a vertical sectional view of a lower mold according to the present invention.

FIG. 7 is a plan view of a lower mold according to the present invention.

FIG. 8 is a partially enlarged vertical sectional view showing a lower clamp structure according to the present invention.

FIG. 9 is a view showing a manufacturing process of a bath according to the present invention.

FIG. 10 is a partial vertical sectional view showing a conventional resin mold.

FIG. 11 is a partial vertical sectional view showing a conventional electroforming mold.

FIG. 12 is a partial vertical sectional view showing a conventional mold.

[Explanation of symbols]

 14 ... Upper mold 15 ... Rib 16 ... Resin plate 20 ... Lower mold 21 ... Metal plate 22 ... Resin plate 30 ... Gel coat 31 ... Resin concrete 32 ... Backup material 33 ... Bathtub

Claims (1)

[Scope of utility model registration request] 1. In a mold for resin molding in which a flow path for a heat medium such as hot water is provided inside the mold, one side of the mold is molded with a metal plate and the other side of the mold is molded with a resin plate. Then, a mold is arranged between the metal plate and the resin plate at the peripheral edge of the mold, and the metal plate and the resin plate are individually attached to the mold by bolts. Clamp structure for resin mold.