JP2006187975A - Reactive injection mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactive injection mold having long life at a low cost. <P>SOLUTION: The reactive injection mold is constituted so as to form a cavity 3 between a first mold 1 and a second mold 2 by superposing the first and second molds 1 and 2 one upon another. The contact regions with a product in at least one of the first and second molds 1 and 2 comprises resin layers 7 and 12 of a silicone rubber. Metal reticulated bodies 8 and 13 are arranged to the backup parts 5 and 10 of the resin layers 7 and 12. The thickness of each of the resin layers 7 and 12 of the silicone rubber is 1-20 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reaction injection mold.

  Reaction injection molding (RIM) is generally performed by mixing a liquid resin at room temperature with a catalyst that causes a polymerization reaction to form a molding material, and then injecting the molding material into a mold to polymerize the reaction. The mold used for the molding is a reaction injection mold (for example, see Patent Document 1). That is, the reaction injection mold can be configured as shown in FIGS.

  The mold shown in FIG. 4 includes an upper mold (core mold) 51 and a lower mold (cavity mold) 52. The upper mold 51 is, for example, an aluminum casting mold, and the lower mold 52 is, for example, an electric mold. That is, the lower mold 52 includes a backup portion 53 such as cement, a frame body (iron frame) 54 surrounding the backup portion 53, and a Ni electroformed layer 55. In the backup portion 53, a cooling pipe 56 is disposed along the Ni electroformed layer 55 on the Ni electroformed layer 55 side. The upper mold 51 is also provided with a cooling pipe 57. When the upper mold 51 and the lower mold 52 thus configured are overlapped, a cavity 58 for forming a product is formed between the upper mold 51 and the lower mold 52.

The mold shown in FIG. 5 is a so-called resin mold. In this case, the upper mold 60 includes a backup part 61 made of cinnabar grains and an epoxy resin, a frame body 62 surrounding the backup part 61, an epoxy layer 63, and between the epoxy layer 63 and the backup part 61. And a laminated body 64 to be disposed. The laminate 64 is a laminate of glass wool cloth and epoxy resin. In the backup unit 61, a cooling pipe 65 is disposed along the stacked body 64 on the stacked body 64 side. Further, like the upper mold 60, the lower mold 67 is disposed between the backup unit 68, the frame 69 surrounding the backup unit 68, the epoxy layer 70, and the epoxy layer 70 and the backup unit 71. The laminated body 72 is provided. In addition, a cooling pipe 73 is disposed along the multilayer body 72 on the multilayer body 72 side in the backup unit 68. When the upper mold 60 and the lower mold 67 configured as described above are overlapped, a cavity 74 for forming a product is formed between the upper mold 60 and the lower mold 67.
JP 11-31242 A

  However, in the case shown in FIG. 4, the cost increases when the number of moldings is small. Further, in the case shown in FIG. 5 that can be reduced in cost by using a resin mold, since it is poor in flexibility and weak against thermal shock, “cracking” occurs due to thermal expansion during molding, and the epoxy layer Since the heat resistance limit of 63 is about 80 ° C. to 100 ° C., it cannot be said that the heat resistance is excellent. Therefore, when the temperature at the time of molding is about 150 ° C. to 180 ° C., it cannot be handled and the service life is short. For this reason, there has been a demand for a reaction injection mold that can be provided at a low cost and has a long life.

  The present invention has been made to solve the above-mentioned conventional drawbacks, and an object thereof is to provide a reaction injection mold that can be provided at a low cost and has a long life.

  Accordingly, the reaction injection molding die according to claim 1 is characterized in that the portion in contact with the product is a resin layer 7 of silicon rubber.

  The reaction injection molding die according to claim 2 is a reaction injection in which a cavity 3 is formed between the first die 1 and the second die 2 by superposing at least the first die 1 and the second die 2. The molding die is characterized in that in at least one of the first mold 1 and the second mold 2, the portions in contact with the product are the resin layers 7 and 12 of silicon rubber.

  The reaction injection mold according to claim 3 is characterized in that the resin layers 7 and 12 of the silicon rubber have a thickness of 1 mm to 20 mm.

  The reaction injection mold according to claim 4 is characterized in that the metal nets 8 and 13 are arranged in the backup portions 5 and 10 of the resin layers 7 and 12.

  According to the reaction injection mold of claim 1, since the part that comes into contact with the product is a resin layer of silicon rubber, the resin layer is excellent in heat resistance and has flexibility and relaxation against thermal shock. Excellent in properties. For this reason, this reaction injection mold can stably prevent “cracking” due to thermal expansion and has excellent durability. That is, in such a reaction injection mold, the use of silicon rubber having excellent heat resistance and flexibility at the site in contact with the product has resulted in a long life that could not be exhibited by conventional resin layers. Can be achieved, and the number of formation can be dramatically increased to reduce the cost. Further, when the resin layer is damaged, the resin layer can be peeled off to form a new silicone rubber resin layer again. Thus, by forming a new resin layer, this mold can be used further, and the lifetime as a mold can be greatly extended.

  According to the reaction injection mold of claim 2, since at least one of the first mold and the second mold is in contact with the product as a silicon rubber resin layer, the resin layer is excellent in heat resistance. And it has flexibility and is excellent in the ease with respect to a thermal shock. For this reason, “cracking” due to thermal expansion can be stably prevented, the service life of the mold can be extended, and the number of moldings by this reaction injection mold can be dramatically increased to reduce costs. Can do. Further, when the resin layer of the mold is damaged, the life as a reaction injection mold can be greatly extended by replacing the resin layer with a new one.

  According to the reaction injection mold of claim 3, since the thickness of the resin layer is 1 mm to 20 mm, the formed resin layer is hardly broken and the shape of the molded product can be stabilized. That is, if the thickness of the resin layer is less than 1 mm, the resin layer is too thin and the resin layer is easily broken. Conversely, if the thickness of the resin layer exceeds 20 mm, the shape of the molded product is not stable.

  According to the reaction injection molding die of claim 4, since the metal network is disposed in the backup portion of the resin layer, the thermal shock to the resin layer can be more reliably mitigated by the metal network, Further extension can be achieved. In addition, when replacing with a new resin layer, there is an advantage that the resin layer can be easily peeled off and a new reaction injection mold can be easily manufactured.

  Next, specific embodiments of the reaction injection mold of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a simplified diagram of a reaction injection mold, which is composed of a first mold (upper mold) 1 and a second mold (lower mold) 2, and includes a first mold 1 and a second mold 2. By overlapping, a cavity 3 is formed between the first mold 1 and the second mold 2. The first mold 1 includes a backup unit 5, a frame 6 that surrounds the backup unit 5, a resin layer 7 that is disposed in contact with the product, and a metal that is disposed on the back side of the resin layer 7. A net-like body 8.

  The backup unit 5 is composed of refractory grains such as cinnabar grains and epoxy resin. Note that a urethane resin, a phenol resin, a urea resin, a melamine resin, a silicone resin, a polyurethane resin, an unsaturated polyester resin, or the like may be used instead of the epoxy resin. The frame 6 is made of a metal such as aluminum or iron. Further, the resin layer 7 is made of silicon rubber. In this case, the thickness of the resin layer 7 is about 1 mm to 20 mm. More preferably, it is about 2 mm to 4 mm. This is because the resin layer 7 is preferably thicker than 1 mm in order not to be broken, and is preferably thinner than 20 mm in order to stabilize the shape of the molded product. Moreover, the metal net-like body 8 is a so-called metal net consisting of, for example, a plurality of longitudinal members made of metal linear bodies and a plurality of lateral members made of metal linear bodies. In addition, the 2nd type | mold 2 is also the 1st type | mold 1 and the backup part 10, the frame 11 surrounding this backup part 10, the resin layer 12 arrange | positioned in the site | part which contacts a product, and this resin layer 12 The metal net-like body 13 is provided on the back side.

  Next, a method for manufacturing the reaction injection mold will be described. In this case, the second mold 2 will be described. First, as shown in FIG. 2 (a), a mold 16 is set on the frame 15, and as shown in FIG. 2 (b), the surface of this mold 16 is built up with clay, wax sheet or the like, and a release layer is formed. 17 is formed, and the frame 15 is filled with refractory grains and the epoxy resin constituting the backup unit 10. At this time, the epoxy resin is mixed with the curing agent, and further filled with a mixture of refractory particles such as cinnabar sand particles. Thereby, the backup unit 10 to be formed is cured. Next, the mold is removed and the release layer is removed to obtain the state shown in FIG. Thereafter, the mold 16 is set again, and the resin layer 12 is formed by filling silicon rubber. At this time, the resin layer 12 to be formed is cured by pouring a mixture of silicon rubber and its curing agent. By the way, in this embodiment, as shown in FIG. 3B, a mixture of silicon rubber and its curing agent is press-fitted using a pressure press 18, but without using the processing press 18, the vacuum The pump may be used to perform so-called “evacuation” or simply flow the mixture. Thus, the second mold 2 as shown in FIG. 3C is formed by performing the steps as described above.

  By the way, since the metal net 13 is arranged in the backup part 10 of the second mold 2, when filling the refractory grains and the epoxy resin as shown in FIG. 2 (b), the metal net 13 And the metal net 13 is provided on the rear side (back side) of the resin layer 12. The first mold 1 can also be manufactured by the manufacturing method shown in FIGS.

  According to the reaction injection mold described above, the parts that come into contact with the product are the resin layers 7 and 12 of silicon rubber. Therefore, the resin layers 7 and 12 are excellent in heat resistance and have flexibility and heat. Excellent relaxation against impact. For this reason, “cracking” due to thermal expansion can be stably prevented, and the service life of the first mold 1 and the second mold 2 can be extended. That is, in such a reaction injection mold, the use of silicon rubber having excellent heat resistance and flexibility at the site in contact with the product has resulted in a long life that could not be exhibited by conventional resin layers. Can be achieved, and the number of formation can be dramatically increased to reduce the cost. In particular, the resin layers 7 and 12 formed of silicon rubber are excellent in heat resistance up to about 200 ° C. Therefore, in the conventional mold having an epoxy layer as shown in FIG. 5, the number of molding is about 50 to 100 at most, but in the reaction injection mold of the present invention, about 1000 to 5000. And improved dramatically. Further, when the resin layers 7 and 12 are damaged, the resin layers 7 and 12 can be peeled off to form new silicon rubber resin layers 7 and 12 again. Thus, by forming the resin layers 7 and 12, this mold can be used further, and the lifetime as a mold can be greatly extended. Specifically, by exchanging the resin layers 7 and 12, it was possible to extend the number of moldings to 1000 to 5000 as in the new model.

  Further, since the metal nets 8 and 13 are arranged in the backup portions 5 and 10 of the resin layers 7 and 12, the thermal shock to the resin layers 7 and 12 can be more reliably mitigated by the metal nets 8 and 13. Further, the service life can be further extended. Moreover, when the resin layers 7 and 12 are replaced with new ones, there is an advantage that the resin layers 7 and 12 are easily peeled off and a new reaction injection mold can be easily manufactured.

  By the way, although the cooling pipe for temperature control is not arranged in the above-mentioned embodiment, like the conventional reaction injection mold shown in FIG. 4 and FIG. You may make it arrange | position the cooling pipe for temperature control in the backup part 10. FIG. Thus, the mold temperature is preferably maintained at about 50 ° C. When the temperature is higher than 50 ° C., the dimensional accuracy of the product is deteriorated due to expansion. On the other hand, when the temperature is lower than 50 ° C., the reaction is insufficient and the gloss of the surface of the product is deteriorated. Because there is a fear.

  Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, either one of the first mold 1 and the second mold 2 may be configured with a conventional epoxy resin layer as a resin layer, or may be configured with a mold. Further, as the metal nets 8 and 13, the longitudinal member and the transverse member may be orthogonal to each other, or may be inclined at a predetermined angle. The outer diameter can also be set arbitrarily. Further, the first mold 1 and the second mold 2 may not have the metal nets 8 and 13.

It is a simplified sectional view showing an embodiment of a reaction injection mold of this invention. It is sectional drawing which shows the manufacturing method of the said reaction injection mold. It is sectional drawing which shows the manufacturing method of the said reaction injection mold. It is sectional drawing of the conventional die for reaction injection molding. It is sectional drawing of the other conventional mold for reaction injection molding.

Explanation of symbols

  1 ··· 1st type 2 ··· 2nd type 3 · · Cavity 5, 10 · · · Backup part, 7, 12 · · Resin layer, 8, 13 · · · Metal network

Claims (4)

  A reaction injection mold characterized in that the part in contact with the product is a resin layer (7) of silicon rubber.   Reaction injection molding in which a cavity (3) is formed between the first mold (1) and the second mold (2) by superposing at least the first mold (1) and the second mold (2). A mold for use in which at least one of the first mold (1) and the second mold (2) is in contact with a product, the silicon rubber resin layer (7) (12). A reaction injection mold.   The reaction injection molding die according to claim 1 or 2, wherein a thickness of the resin layer (7) (12) of the silicon rubber is 1 mm to 20 mm. 4. The reaction injection molding according to any one of claims 1 to 3, wherein a metal net (8) (13) is disposed in the backup part (5) (10) of the resin layer (7) (12). Type.