JP2009119847A - Electric heating pressure-molding mold and injection molding mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate deformation work by locally heating the surface of a molding mold to heat and soften a workpiece or to facilitate pressure working or making the flow of synthetic resin smooth by heating the surface of an injection molding mold. <P>SOLUTION: The electric heating pressure-molding mold is provided with an electric heating layer on one or both surfaces of an upper mold and a lower mold in the molding mold for pressure-molding a woven fabric or a sheet material. The injection molding mold for molding and solidifying molten synthetic resin is provided with a planar electric heating layer on or in proximity to one or both surfaces of an upper mold and a lower mold, an injection means for molten synthetic resin, and a cooling means at one or both of the upper and lower molds. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  According to the present invention, an electric heating layer is provided on a part or all of the surface of a molding die, and a part or all of the surface of the molding die is instantaneously heated to mold a workpiece smoothly and accurately. Heating the raw material injected into the mold by providing an electric heating layer on part or all of the surface of the target electric heating and pressure molding mold or the mold, and providing cooling means within the thickness of the mold And an injection mold for the purpose of cooling.

  Conventionally, a technique of providing an electrothermal layer on the wall or bottom of a vaporizer is known. In addition, a constant temperature type electric heating sheet using carbon particles (or carbon fibers) as a heat generating layer has been proposed.

Next, a technique for embedding an electric heater in the thickness of the mold body is known as a heating and pressing mold.
Utility model registration No. 3124014 Japanese Patent No. 3216911 JP 2000-823 A

  Conventional molds used when molding plastic containers and other plastic products have an electrothermal layer embedded in the mold (Patent Document 3). When the mold is heated, the entire mold is heated to the same temperature, In addition to consuming wasteful heat, it was impossible to bring the mold surface to a predetermined temperature by instantaneous heating (for example, 2 to 5 seconds) and to cool it immediately after molten plastic injection molding. Therefore, there is a problem that the processing speed cannot be increased.

  In addition, the processing mold for processing a film or the like can achieve the purpose by heating only a portion with a high degree of processing. However, if an electrothermal layer is embedded in the mold, the entire mold is heated as a result. Therefore, there is a problem that partial heating and partial molding are difficult.

  The injection mold is a technique for injecting a molten synthetic resin and molding a synthetic resin container or a molded sheet at a high speed. However, when the injection mold is cooled, the molten synthetic resin is flowing. Since the fluidity deteriorates due to cooling, there is a problem that not only a high-pressure pressurized flow is required but also the production of a homogeneous product becomes difficult. Further, if not cooled, the solidification may be delayed and the molding efficiency may be impaired. Therefore, it has been difficult to repeat the process of heating instantaneously and cooling quickly.

  In the present invention, by providing an electrothermal heating layer on the surface of the mold, only the portion is instantaneously heated to solve the problems of the conventional pressure mold.

  That is, the present invention relates to an electric heating characterized in that an electrothermal heating layer is provided in the molding die for press-molding a woven fabric or a sheet material in the vicinity of one or both surfaces of the upper die or the lower die. It is a pressure molding die, and the electrothermal heating layer is provided on the entire surface of the contact surface of the workpiece of the molding die with uniform density or non-uniform density, and the electrothermal heating layer is provided on the curved surface of the molding die. .

  In another invention, the electrothermal heating layer is an insulating layer provided on the surface of a metal mold, an electrothermal layer is provided thereon, and an insulating layer is provided thereon. An electric heating layer is sandwiched, a heat-resistant insulating film is attached to the surface of a mold, a carbon electric heating layer made of carbon particles or carbon fibers is provided on the upper surface of the insulating film, and the upper surface of the carbon electric heating layer A heat-resistant insulating film is applied, and an alumina insulating layer, a nickel-chromium electrothermal layer, and an alumina insulating layer are sequentially deposited on the surface of the mold by plasma spraying.

  In another aspect of the invention, the conventional problem is solved by providing an electrothermal heating layer in the vicinity of the surface of the molding die or by providing a cooling means for the die. In short, the heating layer heats the portion where the injected molten synthetic resin is easy to cool due to the structure of the mold, and ensures a smooth flow of the molten synthetic resin.

  In the above, when a layer having sufficient strength is provided on the surface of the electrothermal layer (for example, when the metal or alumina layer is the surface), it can be provided on the surface of the mold, but the surface of the electrothermal layer is an insulating film. Since there is no strength, it is necessary to provide a protective layer such as a thin metal plate. Therefore, an electrothermal heating layer is provided on the surface or in the vicinity of the surface. The protective layer is preferably a material that can withstand the flow of the molten material and the molding pressure and has good heat conduction.

  In addition, when a minute uneven portion is provided on the inner wall surface of the mold (for example, when a minute uneven portion is provided on the surface of a product, a minute uneven portion is provided on the inner wall surface of the mold), a surface covering plate is required as a protective layer. The electrothermal layer is provided close to the surface of the mold.

  In other words, the present invention provides an injection mold for molding and solidifying a molten synthetic resin, an electrothermal heating layer is provided in the vicinity of one or both surfaces of the upper mold or the lower mold, and an injection means for the molten synthetic resin (known in the art) And an injection mold characterized in that the upper mold and lower mold cooling means are provided, and the electrothermal heating layer is sprayed with an insulating material on the mold surface. An insulating layer formed by spraying an electric heating material, and an insulating layer formed by spraying an insulating material are sequentially deposited. The electric heating layer insulates the carbon electric heating layer. It is sandwiched between layers.

  In another aspect of the invention, the electrothermal heating layer is provided with a recessed portion (or without a recessed portion) in the molding die, and an insulating layer is provided by applying a ceramic material from below the recessed portion. An electric heating layer is formed by applying carbon particles on the top, a ceramic material is applied on the electric heating layer to provide an insulating layer, an electroless plating layer is provided on the inner surface of the mold, and the inner surface of the mold is It is an electric heating mold characterized by a series of flat surfaces, and the cooling means is a laying flow pipe of cooling fluid (for example, cold water).

  In the above, the insulating material (for example, ceramic material) carbon particles are applied by spraying or electrostatic coating. When spraying the insulating material, thinner is used as a diluent, and the dilution rate is 5 to 15 wt% by spraying and 10 to 50 wt% by electrostatic coating. However, it varies depending on the particle size of the insulating material. According to the material).

The standard film thickness of the coating is 20 to 40 μm, but varies depending on the material and purpose. For example, the carbon layer for heat generation varies depending on the required temperature. Therefore, the number of times of painting is also set to 1 to 2 times. From the above specifications, the standard usage amount is 200 g / m ² / time, but the usage amount depends on the coating film. In particular, in the case of a carbon layer for heat generation, a large difference occurs depending on the required temperature. If it coats by the above, after pre-drying at 80-160 degreeC for 5 minutes-15 minutes and then drying at 200-400 degreeC for 10 minutes-20 minutes, electroless plating is given.

  The carbon layer needs to be heated to 150 ° C. to 200 ° C. within 0.5 seconds to 2 seconds (the above conditions are preferable from the viewpoint of mold availability).

  Next, another invention is an injection mold for molding and solidifying a molten synthetic resin. Heating / cooling in which an electrothermal heating layer and a cooling means are set in proximity to one or both surfaces of the upper mold or the lower mold. The injection mold is characterized in that the unit is embedded, and the heating / cooling unit is a set of an electric heating layer and a cooling pipe.

  In the above, the electrothermal heating layer on the surface of the mold is heated to a predetermined temperature (eg, 150 ° C.) instantaneously (within about 1 second) and cooled instantaneously (eg, within 1 second) (cooled to the solidification temperature of the synthetic resin) .

  In the above, since the mold main body is cooled with water, for example, it can be cooled instantaneously. On the other hand, since it is a kind of surface heater in heating, it is instantaneously heated to a set temperature (for example, 150 ° C.). In the above, the cooling may be slowed down to cool the entire mold, so a cooling pipe may be laid on the surface to speed up the cooling.

  Since the electrothermal heating layer of the present invention is a very thin layer having a thickness of, for example, about 1 to 2 mm, the layer can be freely and accurately deposited even if the mold surface is curved.

  Further, since only the surface of the mold is heated, the work side rather than the mold surface is heated, and both heating and cooling are quick (for example, within 1 second).

  When carbon particles are deposited as the electrothermal layer, an electrothermal heating mold for automatic constant temperature can be obtained by selecting the density of the carbon particles. Moreover, in the case of the woven sheet | seat by carbon fiber, an electrothermal temperature can be adjusted (for example, the preset temperature between 100 degreeC-300 degreeC can be selected).

  Furthermore, if an electrothermal heating layer in which a nickel-chromium layer is sandwiched by an alumina insulating layer by plasma spraying is used, the durability is high and it can withstand long-term continuous use.

  Since the material to be molded of the present invention is, for example, a woven fabric or a film of organic fibers or inorganic fibers, processing time can be shortened and molding accuracy can be improved by heating at an appropriate temperature. In addition, a conventionally known synthetic resin can be used as a molding material for an injection mold, but fluidity can be ensured by heating the mold, so a high pressure of several hundred kg or more is required. Not. For example, it can be quickly filled with a pressure of about 100 kg.

  In the present invention, since the electrothermal heating layer is provided on the surface of the upper mold, the lower mold, or both upper and lower molds for press-forming a work such as a woven fabric or a sheet material, the processing surface is directly heated. , Instantaneous heating and cooling (0.5 seconds to 3 seconds) are effective.

  Further, if a high-density electrothermal heating layer is provided on a surface with a high degree of processing, there is an effect that the workpiece can be formed rationally and efficiently.

  Furthermore, by thermoforming, the processing speed can be increased (for example, twice the normal speed), and there are various effects such as high precision and fine finishing.

  In addition, in the injection mold, since the mold is heated at the time of material injection, the flow of the material is good, there is no need to make it high pressure, and even in a large size, the material is heated and cooled evenly by temperature control. There is an effect that the product becomes uniform, and the molding and releasing speed can be increased (high efficiency). In short, there is an effect that the machining efficiency can be improved and the product accuracy can be kept high even at a relatively low inflow pressure.

  According to the present invention, the heating and pressing mold is configured such that the electrothermal heating layer is densely arranged in the non-planar portion in the surface of the upper mold of the molding die, and the electrothermal heating layer is sparse or absent in the plane portion.

  In addition, in the vicinity of the upper and lower mold surfaces of the injection mold, a planar electrothermal heating layer is provided, and a cooling means is provided to keep the heat from solidifying by heating at the time of material injection, and to melt the synthetic resin. An injection mold was constructed that cooled to the solidification temperature and achieved its rationalization.

  An embodiment of the present invention will be described with reference to FIG. 1. In a molding die 5 in which a workpiece 3 such as a sheet is curvedly formed by an upper die 1 and a lower die 2, the thickness of the electrothermal heating layer 4 is formed on the inner surface of the lower die 2. The groove 6 having the same depth is provided, and the electrothermal heating layer 4 is fitted and fixed in the groove 6 so that the processed surface is formed flush. The electrothermal heating layer 4 is obtained by sandwiching an electrothermal layer 4b with insulating layers 4a and 4a.

  The electrothermal heating layer 4 is arranged roughly according to the degree of processing of a workpiece such as a sheet. The electric heating layers 4 and 4 are provided with lead wires 7 and 7, respectively. Connect to 8.

  For example, if a hole for the cord 8 is provided in the upper die 1 and the cord 8 is inserted into the hole and then connected to a power source near the shaft, there is no electrical problem even if the upper die moves continuously and quickly.

  According to the said Example, the objective can be achieved by making the electrothermal heating layer 4 into arbitrary set temperature of 100 to 200 degreeC by supplying with electricity through the code | cord | chord 8, for example. In the above embodiment, the electrothermal heating layer 4 is embedded in the groove 6, but it can also be deposited on the mold surface.

  As the electrothermal heating layer 4 described above, a conventionally known layer can be used (whether the heat transfer material and the insulating material are each formed by thermal spraying or molding using a carbon electrothermal layer).

  The present invention utilizes the material or characteristics of the electrothermal heating layer, and does not itself have the technology of the invention, but is characterized by providing the electrothermal heating layer in a metal mold.

  2A, the electrothermal heating layer 4 is densely provided on the surface of the inner surface of the upper mold 1 having a high degree of processing.

  Also in this embodiment, since the electrothermal heating layer 4 is fitted and installed in the groove of the upper mold 1, the processed surface of the upper mold 1 is flush.

  Referring to FIG. 2B, another embodiment of the present invention will be described. A groove having the same depth as the thickness of the electrothermal heating layer 4 is provided on the surface of each of the upper mold 1 and the lower mold 2, and each groove is provided. The electrothermal heating layer 4 is inserted and installed. Therefore, the surfaces of the upper mold and the lower mold are both flush with each other, and the workpiece is heated from both sides to facilitate molding. In the above, when the strength of the outer surface of the electrothermal heating layer 4 is insufficient, it may be covered and reinforced with a protective plate.

  If another embodiment of the present invention is described with reference to FIG. 3, electrothermal heating layers 4 and 4 are provided on the surfaces of the upper mold 11 and the lower mold 12. In the electrothermal heating layers 4 and 4, a strip-shaped electrothermal layer 4b (for example, nickel chrome) is sandwiched between insulating layers 4a and 4a (for example, an alumina insulating layer), and the electrothermal layer 4b is connected to lead wires 7 and 7 and the like. , Cords 8 and 8 are connected.

  The strip-shaped electrothermal layer 4b is heated instantaneously (about 0.5 seconds) when energized and cooled quickly when shut off. Therefore, the strip-shaped electrothermal layer 4b is heated when pouring the resin melt and cooled immediately after the pouring is completed. be able to. Therefore, it can be heated at the time of injection molding of the synthetic resin material, and can be cooled immediately after filling.

  If this mold is used, the material is quickly filled at the time of injection and cooled quickly.

  Referring to FIGS. 5 and 6, another embodiment of the present invention will be described. The partition plates 13 and 13 are erected on a metal box 9 having the same quality as the injection mold (the plane shape is similar to the bottom of the mold). The electrothermal heating layers 4, 4 and the cooling pipes 14, 14 were alternately laid between the partition plates 13, 13, and the metal plate 9 was covered with the lid plate 15 to constitute the cooling / heating unit 10. The cooling / heating unit 10 is similar to the shape of the bottom surface 12a of the lower mold 12, and is accommodated in a recess 16 provided in the bottom of the lower mold 12, and the peripheral edge of the cover plate 15 is the bottom surface of the lower mold 12 Molded to the same level. A head pipe 17 and a feed pipe 18 connected to the head pipe 17 are provided on one side of the lower mold 12. In the figure, 21 is an injection hole.

  In the above embodiment, if the electrothermal heating layer 4 is energized, it is heated to a set temperature (for example, 150 ° C.), so that the injected synthetic resin flows smoothly without being cooled, and is filled in the mold space. The Then, if the refrigerant (cooling air, cooling water, etc.) is fed to the feed pipe 18 as indicated by arrow 19, the refrigerant enters the cooling pipe in the mold 12, cools the bottom of the mold, and the arrow 20 Thus, the injected molten synthetic resin is instantly cooled and solidified.

  As described above, at the time of injection of the synthetic resin, the mold is heated to prevent solidification or increase in viscosity, thereby smoothening the flow of the molten synthetic resin and preventing deterioration, and then cooling to solidify.

  Since the conventional type is not heated, there is a possibility that the melted synthetic resin may become highly viscous or deteriorated (partially solidified), and there is a problem that high pressure is required to flow at high speed when it is narrow or thin. . However, as described above, if the synthetic resin used is appropriately heated, there is no risk of deterioration, and there is an advantage that high pressure is not required. For example, since the feeding pressure can be reduced to 1/10 or less, the method of use and the equipment used can be greatly improved.

  In the above, when an injection mold is used, since a large number of products must be molded in a short time, heating and cooling must be instantaneously changed. Therefore, the purpose was achieved by arranging a refrigerant feeding pipe and feeding the refrigerant during cooling.

  That is, since the calorific value and the calorie to be cooled are known, the purpose of instantaneous heating and cooling can be achieved by providing an electrothermal heating layer or feeding a necessary amount of refrigerant to satisfy this. .

  In the above embodiment, since the cooling / heating unit 10 is adopted, a necessary recess 16 is provided in a conventional mold, and the cooling / heating unit 10 is set in the recess 16, so that the mold is formed. There is no risk of requiring special labor and technology for manufacturing.

  Next, another embodiment will be described with reference to FIG. 5 (b). Partition plates 13 and 13 are provided in the recess 16 provided in the bottom surface portion of the lower mold 12, and an electrothermal heating layer is provided between the partition plates 13 and 13. 4 and the cooling pipe 14 were alternately installed, and the cover plate 15 was crowned on the upper part to constitute the cold / hot part of the present invention.

  In the above embodiment, since the cold / heat unit 10 is not used, it is set when the mold is formed. Therefore, according to the shape of the mold, it is possible to provide a cold / hot layer having the ability to correspond to the target heating temperature (or degree of cooling).

  According to the embodiment, since the surface of the mold can be appropriately heated and cooled, the injection molding can be advanced in a thermoeconomic manner.

  7 and 8, the insulating layer 23, the electrothermal layer 24, and the insulating layer 23 are sequentially provided on the inner surface of the mold 21 to form an electrothermal layer, and the plating layer 25 is formed on the upper insulating layer. (When there is no recessed portion, FIG. 7A). Moreover, the recessed part 22 is provided in the arbitrary positions of the inner surface of the type | mold 21, The insulating layer 23 (thickness 0.2m-0.5mm) by ceramic powder coating is provided in this recessed part 22, and this insulating layer 23 is provided. An electric heating layer 24 (thickness 0.5 mm) made of carbon particles is provided on the upper surface of the electrode, and an insulating layer 23 (thickness 0.2 mm to 0.5 mm) made of ceramic powder paint is provided on the upper surface of the electric heating layer 24. A plating layer 25 (thickness 0.4 mm to 0.8 mm) is provided on the upper surface of the insulating layer 23 and the upper surface of the mold 21.

  The insulating layer 23 may be replaced with ceramic powder, and a heat-resistant synthetic resin film (for example, Teflon (registered trademark), silicon film) may be used.

  The diluent is usually thinner, but in the case of carbon particles, an electrically conductive adhesive may be used.

  The carbon layer and the insulating layer are dried after coating (spraying), respectively, and then move to the next step. For example, after providing an insulating layer (ceramic powder), it is preliminarily dried at 150 ° C. for 10 minutes, and then dried at 380 ° C. for 15 minutes.

  After the treatment is completed and it is confirmed that the insulating layer has a predetermined thickness and a predetermined flatness, the conductive layer is provided by spraying carbon particles. Next, preliminary drying is performed at 150 ° C. for 10 minutes, and main drying is performed at 350 ° C. for 15 minutes to 20 minutes. An insulating layer is provided on the upper surface of the carbon layer in the same manner as described above.

  An electroless plating layer is provided on the insulating layer. When the film formation is insufficient in relation to the insulating layer, a material having an affinity for electroless plating (for example, nickel plating) as a pretreatment ( In some cases, a known material is applied.

  In the above, the electrothermal layer is applied to a thin layer (for example, 0.5 mm) with a mixed material obtained by mixing carbon particles with an electrically conductive diluent. Moreover, an insulating layer (thickness 0.2 mm-0.5 mm) mixes a diluent (for example, thinner) with ceramic powder, and applies this mixed material.

  Therefore, even if an electrothermal layer and two insulating layers are laminated, the thickness is 2 mm or less. The thickness of each of the layers is an example, and may be further increased. Further, an electroless plating layer (thickness 0.5 mm to 1 mm) is provided over the entire surface of the mold, and a fine uneven portion is provided on the surface of the molding object by providing a fine uneven portion on the surface of the plated layer.

  In the embodiment, silver foils 26 and 26a are deposited on both sides of the upper surface of the electrothermal layer 24 in FIG. 8, lead wires 27 and 27a are connected to the silver foils 26 and 26a, respectively, and the lead wires 27 and 27a, the silver foil 26, A heat generating circuit can be constituted by 26 a and the electrothermal layer (carbon particles) 24.

  The plating layer is an electroless plating layer, for example, nickel plating.

  The electroless plating is performed by a known method, but is provided to make the surface of the shape a uniform surface and to provide minute uneven portions. Further, the plating layer can achieve uniformity in heating and cooling temperatures, and can achieve uniformity in the quality of a product (for example, a synthetic resin sheet).

Regarding the electroless plating described above, an example of Ni plating is as follows. The surface of the metal serves as a catalyst, and a dehydrogenation reaction of hypophosphite ion occurs, and becomes atomic hydrogen H and metaphosphite ion PO ₂ ^— .

[H ₂ PO ₂ ] ⁻ → [PO ₂ ] ⁻ + 2H (cat) (1)

  Therefore, metaphosphite ions are combined with water to become phosphite ions.

[PO ₂ ] ⁻ + H ₂ O → [H ₂ PO ₃ ] (2)

  Part of atomic hydrogen H is directly bonded to form hydrogen gas, part becomes a reducing agent for nickel ions, deposits nickel, part reduces hypophosphorous acid to form phosphorus, Make an alloy.

2H (cat) → H ₂ ↑ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (3)

Ni ²⁺ + 2H (cat) → NiO + 2H ⁺ (4)

[H ₂ PO ₂ ] ⁻ + H (cat) → PO + DH ⁻ + H ₂ O (5)

  Since the reaction of formula (3) proceeds at a reaction rate twice that of formula (4), the utilization efficiency of hypophosphite in a convenient plating state is about 33% in the case of an acid bath. That is, 3 moles of hypophosphorous acid are required for 1 mole of nickel plating.

  The electroless plating Ni-P plating film has the following characteristics.

Chemical composition: Ni: 90% to 96%, P: 4% to 10%
Crystal structure ... The precipitation state is amorphous, but it is formed by heat treatment.
It becomes crystalline.
Specific gravity: 7.9 in the precipitated state and 7.8 in the heat treatment.
Hardness ... Vickers hardness (HV) 500-700,
The lower the phosphorus content, the higher the hardness. Heat at 400 ° C
If processed, it becomes HV950 or more.
Electrical resistance ... ・ By performing heat treatment at 60μΩ / cm in the deposited state
1/3.
Thermal expansion coefficient: 13.0 to 14.5 μm / m ³ C

  The electroless nickel plating can be a composite plating as follows.

Abrasion-resistant coating: Silicon carbide (SiC), aluminum oxide (Al ₂ O
₃ ), B ₄ C diamond can be co-deposited
wear.
Corrosion-resistant coating: Co-depositing metal powders such as Cr, Mo, W, Ti
You can also.

(A) The front view which carried out the cross section of a part of Example of the press-molding die of this invention, (b) The same partially expanded sectional view, (c) Explanatory drawing which similarly shows the electrical connection of each electrothermal heating layer. (A) Partial sectional view of another embodiment, (b) Partial sectional view of another embodiment. (A) The perspective view which abbreviate | omitted and partially cut the injection mold, (b) The same partially expanded sectional view. Explanatory drawing which similarly shows the electrical connection example of the electrothermal heating layer in FIG. (A) Partial cross-sectional enlarged view of the heating / cooling unit, and (b) Partial cross-sectional enlarged view in which heating / cooling means are embedded in the surface of the mold. (A) The perspective view of the Example of a lower mold | type similarly, (b) The top view which was also partially cross-sectioned. (A) The cross-sectional enlarged view which abbreviate | omitted a part of other Example similarly, (b) The cross-sectional enlarged view which abbreviate | omitted a part of the other Example similarly. (A) The top view which abbreviate | omitted a part of other Example similarly, (b) The AA cross-sectional enlarged view which abbreviate | omitted a part in figure (a).

Explanation of symbols

1 Upper mold 2 Lower mold 3 Work 4 Electric heating layer 5 Mold 6 Groove 7 Lead wire 8 Cord 9 Metal box 10 Cooling / heating unit 11 Partition plate 12 Lower mold 13 Partition plate 14 Cooling pipe 15 Cover plate 16 Recess 17 Head pipe 18 Feeding pipe 23 Insulating layer 24 Electric heating layer 25 Plating layer 26 Silver foil

Claims (14)

  An electric heating and pressing mold characterized in that an electrothermal heating layer is provided in the vicinity of one or both of the upper mold and the lower mold or a surface in a molding mold for press molding a woven fabric or a sheet material.   2. The electric heating and pressing mold according to claim 1, wherein the electrothermal heating layer is provided with a uniform density or a non-uniform density over the entire contact surface of the workpiece of the mold.   2. The electric heating and pressing mold according to claim 1, wherein the electrothermal heating layer is provided on a curved surface of the mold.   2. The electric heating and pressing mold according to claim 1, wherein the electrothermal heating layer is provided with an insulating layer on the surface of the molding die, an electrothermal layer provided thereon, and an insulating layer provided thereon.   2. The electric heating and pressing mold according to claim 1, wherein the electric heating layer is a carbon particle electric heating layer sandwiched between insulating sheets.   In an injection mold for molding and solidifying a molten synthetic resin, a planar electrothermal heating layer is provided in the vicinity of one or both surfaces of the upper mold or the lower mold, and an injection means for the molten synthetic resin and the upper mold Alternatively, an injection mold characterized in that a cooling means is provided on one or both of the lower molds.   The electrothermal heating layer is provided with a recessed portion in the injection mold, and an insulating layer is formed by applying a ceramic material from below the recessed portion, and an electrically heated layer is formed on the insulating layer with carbon particles or carbon fibers. 7. The injection mold according to claim 6, wherein a ceramic material is applied on the electrothermal layer to provide an insulating layer, and an electroless plating layer is provided on the inner surface of the mold to form a series of flat surfaces.   A heat-resistant insulating film is attached to the surface of the injection mold, a carbon electric heating layer made of carbon particles or carbon fibers is provided on the upper surface of the insulating film, and a heat-resistant insulating film is attached to the upper surface of the carbon electric heating layer. 7. An injection mold according to claim 6, wherein a protective plate is deposited on the insulating film.   The injection mold according to claim 6, wherein an alumina insulating layer, a nickel-chromium electrothermal layer, and an alumina insulating layer are sequentially deposited on the surface of the injection mold by plasma spraying.   The electric heating layer was formed by sequentially depositing an insulating layer formed by spraying an insulating material on the surface of the mold, an electric heating layer formed by spraying the electric heating material, and an insulating layer formed by spraying the insulating material. The injection mold according to claim 6.   The injection mold according to claim 6, wherein the electrothermal heating layer includes a carbon electrothermal layer sandwiched between insulating layers.   7. The injection mold according to claim 6, wherein the cooling means has a cooling fluid flow pipe embedded in the mold.   In an injection mold for molding and solidifying a molten synthetic resin, a heating / cooling unit in which an electrothermal heating layer and a cooling means are set is embedded in the vicinity of one or both of the upper mold and the lower mold. An injection mold.   The injection mold according to claim 13, wherein the heating / cooling unit is set with an electrothermal layer and a cooling pipe.

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