JP5020351B2 - Molding method of carbon powder composite resin - Google Patents

Description

  The present invention relates to a method for molding a carbon powder composite resin used in a rice cooker capable of electromagnetic induction heating. It is characterized by a mold structure used for injection molding of a carbon powder composite resin mainly composed of carbon powder and a binder that is a high carbon-containing substance.

  The mainstream of stoves and rice cookers using electromagnetic induction heating by eddy currents of induction heating coils is a clad material formed by laminating a high heat conductive metal such as aluminum or copper on a magnetic metal. However, the clad material has a problem that it is difficult to process into a shape such as a pan or a kettle, and it is easy to peel off at the interface with a heat-resistant resin coating surface such as a fluororesin.

  For this reason, it has been proposed to use a carbon aggregate having excellent conductivity and conductivity in place of the conventional electromagnetic induction heating material (see, for example, Patent Document 1).

  Also obtained by pressing a mixture of carbon particles such as coke and a high carbon content such as phenol or pitch, which is a binder, into a cylindrical shape and heating at 1000 to 3000 ° C. in an oxygen-free atmosphere. It has been disclosed that a carbon agglomerated body, which is cut into a cooking utensil such as a rice cooker, is effective as a cooking utensil at a high temperature (see, for example, Patent Document 2).

  According to the above-described method for manufacturing a cooking utensil, there is a problem that the material in the hollow portion of the concave container, which occupies most of the cutting of the carbon sintered body, is largely discarded and the number of processing steps is large. Furthermore, it is difficult to detect the presence of defects in the carbon compression body in advance, and the design and strength are adversely affected by being exposed by cutting.

  As a means to solve these problems, a molding material, which is a mixture of carbon particles and a binder material such as a phenol resin raw material liquid and tar pitch, is injected into a mold, pressed, and molded. Means for obtaining a carbon aggregate formed into a pan-like shape by firing the formed product has been proposed (see, for example, Patent Document 3).

  However, in order to obtain a carbon agglomerated molded product with excellent strength, electrical conduction, and heat conduction necessary for use as a cooking utensil capable of electromagnetic induction heating, the phenolic resin content of the molding material must be reduced. It is essential to reduce it. On the other hand, the carbon powder surface does not have sufficient wettability, so it easily aggregates, the apparent viscosity is improved and the fluidity is lowered, and the weld part where the flow ends merge is designed as a rigid streak. Defects were observed, and there was a problem that the homogeneity as the wall surface of the molded product was easily lost as the strength decreased.

JP-A-9-75211 JP-A-9-70352 JP 2007-44257 A

  As mentioned above, in order to form a rice cooker by injection molding without forming a weld, it is important to secure a flow form in which the molding material reaches the outer periphery of the flange at the top of the rice cooker at the same time. Most preferably, a gate is provided at the center of the bottom of the product. However, the molding material discharged from the gate collides with the surface of the inner mold that forms the inner wall surface of the molded product facing the gate to generate turbulent flow, thereby modulating the color and gloss of the portion of the molded product. In addition, when a large-diameter gate that reduces the collision speed is provided, it takes a lot of work to process the gate cutting part, and cracks occur in the molded product wall due to the gate cutting load in the mold. This causes the problem of

  In addition, in the central part of the bottom surface where the gate is located, the final filling material stays in the local area where the molding material that is in a molten state lower than the mold temperature collides with the lower mold and cools, so that the reaction occurs from the peripheral part. There was a problem that the tensile stress generated by the cure shrinkage was delayed and the internal stress was accumulated, leading to the generation of cracks and the extreme deterioration of physical properties.

The present invention has been made in order to solve the above-described problems, and provides a method for molding a carbon particle composite resin for the purpose described below.
(1) On the inner mold surface corresponding to the center of the bottom surface of the pot-shaped molded product of the injection mold, deterioration of design properties due to fixation of graphite particles and wear of the mold, generation of cracks and physical properties in the molded product layer Avoid degradation.
(2) Suppression of crack generation and impact strength reduction due to residual stress due to reaction delay in the vicinity of the gate.

In the method for molding a carbon particle composite resin according to the present invention, a discharge pipe provided with a gate at the contact position of the outer wall near the top dead center of an internal rod is disposed on a corresponding portion of the bottom central outer wall of the pot-shaped molded product. It is a shaping method by heating and pressurizing by using a mold, injecting molding material mainly composed of carbon particles and phenol resin,
Immediately after injection, the rod is lowered and pressurized, and then the pressure is released and further recovered.

  In the molding method of the carbon particle composite resin according to the present invention, the pressure is released and further recovered after the rod is lowered and pressurized immediately after injection. The resulting low-temperature molding material was dispersed, and the occurrence of tensile strain in the surface direction was reduced by applying compressive stress to the shrinkage behavior of the part. As a result, crack generation and impact strength reduction are suppressed, and the deformation at the contact part between graphite particles of the injection molded product is restored to its original shape, ensuring a dense filling state and homogenizing the molded product. I was able to achieve it.

FIG. 3 is a conceptual cross-sectional view of a molding die 10 showing the first embodiment. The figure which shows Embodiment 1 and the figure which shows the comparison result of the falling ball impact strength in the bottom face center part of a rice cooker. It is a figure shown for a comparison and is a conceptual diagram of the conventional molding die 110 (the gate 101 vicinity).

Embodiment 1 FIG.
Hereinafter, an example of an embodiment for carrying out the present invention will be described. The present embodiment relates to a method for molding a carbon powder composite resin (a structure of an injection molded gate having a gate blocking and compression function). First, an outline of the first embodiment will be described.

  When injection molding of a thin molded product having a large L / T using a mixture with a phenol resin having a high content of graphite particles, the viscosity of the molding material as the mixture is extremely high and the fluidity is poor. There is a problem that the density distribution of the molded product is large. In particular, in a pot-shaped molded product such as a rice cooker, in addition to reducing the strength of the weld and suppressing excessive residual stress, the design of the molded product appearance due to secondary flow depending on the pressure distribution after filling the mold In order to suppress property loss, flow control of the molding material in the mold is essential. For this reason, the molding material has a suitable reaction rate that can suppress an excessive increase in the fluid viscosity due to retention in the molding machine (molding die).

  However, because the rice cooker has a large L / T and is a thin-walled molded product, it is necessary to adopt a molding means that injects from the gate installed at the center of the bottom so that the molding material reaches the entire circumference of the flange that does not form a weld. Required. However, in the conventional gate shape, since the discharged molding material collides with the opposing inner wall surface and locally generates turbulence, the surface roughness of the portion is modulated to deteriorate the appearance design. In order to avoid this, the application of a gate with an enlarged gate diameter causes cracks in the inner layer of the molded product that received an excessive load when the gate is cut in the mold, and is often used for removing traces. This causes a problem of requiring labor.

  In addition, L / T has a plane part having a constant thickness, the thickness of the plane part is T, and the distance between the end of the plane part farthest from the gate and the gate is L. Say ratio.

  In addition, in the center of the bottom surface where the gate is located, the bottom center inner surface where the molding material having a temperature lower than the mold temperature collides is locally cooled and the final filling stays. There was a problem that the tensile stress of curing shrinkage was concentrated and the tensile stress was concentrated, leading to the generation of cracks and extreme deterioration of physical properties.

  In a molding die for obtaining a carbon condensation molded product with high heat generation efficiency of dielectric heating obtained by baking an injection molded product using a molding material in which graphite powder is mixed with phenol resin at a high content rate, discharging the molding material The above problem is solved by providing a gate having the following structure at a position corresponding to the center of the bottom of the molded product corresponding to the position.

  In other words, when filling the mold cavity with the molding material at a low speed, the mold cavity is temporarily held and heated to approximate the mold temperature, and this is allowed to flow so that the molding material at the final filling position is removed from the bottom center position. Exclude. Furthermore, an improvement in strength is achieved by pressurizing around this portion.

  In order to achieve the above object, an injection mold is provided with a cylindrical discharge pipe having a built-in rod in the center of the bottom surface where a molding material starts filling the mold, and a discharge pipe contact at the top of the discharge pipe. The molding material was discharged from the gate provided at the position so as to go around the inner wall of the discharge pipe, and the mold cavity was filled through the discharge pipe. As a result, the inflow speed from the discharge pipe into the cavity is greatly suppressed, and the molding material remaining and heated after the completion of the discharge is pushed out to the mold cavity by lowering the rod to the bottom center position. A certain low temperature molding material was excluded and pressure was applied to the molded product.

  Furthermore, in the pressure application step described above, the pressure is repeatedly applied to and released from the rod, and the edges of the graphite particles having a high content are kept from coming into contact with each other and being held in an excessively distorted state. did.

  As described above, from the completion of injection of the molding material including a series of mold drives to the completion of curing, the mold and the discharge pipe maintain the holding pressure and temperature, and after this stage is completed, the mold is opened and the injection molded product is taken out. It will be.

  In the portion corresponding to the inner center of the rice cooker, the design of the inner mold (lower mold) is fixed by graphite particles and the design is deteriorated due to wear of the mold, the crack is generated by releasing the remaining strain, or the residue is based on the strain. It was possible to avoid deterioration of physical properties due to stress.

  On the other hand, since the molding material was discharged while repeating the pressurization and release of the discharge pipe held at a high temperature immediately after injection, the reaction was delayed at a relatively low temperature compared with other parts at the part, causing the shrinkage to cure. Since the molding materials that tend to concentrate the strain are eliminated and dispersed, the generation of cracks and impact strength reduction are suppressed, and the contact of the sharp corners of the graphite particles of the injection molded product is avoided, resulting in a stable contact state. Since it is ensured and a dense filling state is ensured, homogenization of the molded product can be achieved.

  Inner pot molding of a rice cooker, which is a means for obtaining a pot-shaped molded article by injection molding, which is a pot-shaped molded article using a mixture of graphite powder and a phenol resin as a binder as a raw material The manufacturing method of the electromagnetic induction heating cooker obtained by baking the product in an oxygen-free atmosphere will be described in detail below.

  The molding material is graphite powder obtained by calcining petroleum coke at an oxygen-free high temperature (3000 ° C) and pulverizing to 0.1 mm or less, phenol diluted with water, quaternary ammonium salt type cationic activity as a surfactant. An agent is added and formaldehyde is added and polymerized while stirring so that the graphite particles are uniformly dispersed at an arbitrary temperature.

  A semi-cured phenol resin having an arbitrary degree of polymerization by adjusting the temperature and time during the reaction is such that the surface of the carbon powder has a coating amount of 25 wt%, and the obtained molding material A is 40 ° C. A vacuum drying treatment was performed at the following low temperature.

  As the surfactant, for example, a surfactant which exhibits a polymer electrolyte behavior and forms a polyion complex with a phenol resin in a polymerization process is used.

  Note that the molding material may be a mixture of organic fibers having a decomposition start temperature lower than that of the phenol resin and a low carbon residual ratio in the firing stage.

  The uncured phenol resin obtained by the above method was polymerized in a state where the surface of the carbon particle was always wet with the raw material liquid for polymerizing the phenol resin, so that it was held as a film on the outer peripheral surface of the carbon particle. A granular raw material for molding was obtained.

  Moreover, what mixed the mixture of the above-mentioned graphite particle and a novolak-type phenol resin in the ratio of 75:25 was used as a comparative example. As the mixture, a molding material B obtained by dissolving a phenol resin in alcohol or the like, kneading while spraying on graphite in a kneader, and then drying was used.

  In addition, the graphite powder contains a lot of fine powder, and since the sharp edges formed by crushing are in contact with each other and stick easily, the graphite powder is agglomerated when kneaded in the groove of the rotating screw in the injection molding machine. Then, it stays in the screw and falls into a difficult situation. For this reason, the above-mentioned problem can be solved by using graphite powder having a particle diameter of 100 to 300 μm.

  Next, the molding material (molding material A and molding material B) is provided on the outer peripheral surface of the mold under injection molding conditions of a cylinder temperature of 60 ° C., a nozzle temperature of 110 ° C., and a mold temperature of 165 ° C. The molded product (this embodiment, comparative example) was obtained by injecting from the (gate), pressurizing, demolding after holding as a curing time of 3 minutes.

  At this time, the injection pressure of the molding material B mixed with the low-melting phenol resin was 10.5 Mpa, whereas the molding material A according to the present embodiment filled the mold at a low pressure of 7.5 MPa. Completed. This is because when the molding material A flows in the mold, the sharp edges formed by crushing the graphite particles are rounded by coating the surface of the graphite particles with an uncured phenol resin. This is because fluidity is improved because the phenol resin is difficult to agglomerate due to the pressure accompanying flow as the phenol resin melts.

  FIG. 3 is a view for comparison, and is a conceptual diagram of a conventional molding die 110 (near the gate 101). The molding material melted in the injection molding machine (molding mold) fills the mold cavity for shaping the inner pot molded product. At this time, the structure of the conventional molding die 110 at the bottom center position where the molding material for molding the rice cooker inner pot is filled in the die cavity is as shown in FIG.

  The conventional molding die 110 has a structure in which the gate 101 is disposed on the surface of the upper die 107 and is discharged, but the molding material discharged from the gate 101 collides with the lower die inner wall surface 106a of the lower die 106 at a high speed. After that, it flows in the mold cavity 103.

  Therefore, in the conventional molding die 110, the molding material discharged from the gate 101 collides with the lower mold inner wall surface 106 a that forms the molded product inner wall surface facing the gate 101, thereby generating a turbulent flow. Modulates the color and gloss of the part.

  In addition, in the central portion of the bottom surface where the gate 101 is located, the final filling material stays in the local portion where the molding material that is in a molten state lower than the mold temperature collides with the lower mold 106 and is cooled. There was a problem that the reaction was delayed and the tensile stress generated by the curing shrinkage concentrated to accumulate the internal stress, resulting in the generation of cracks and the extreme deterioration of physical properties.

  FIG. 1 shows the first embodiment, and is a conceptual cross-sectional view of a molding die 10. The molding die 10 (injection molding die) is a cylindrical discharge pipe 4 (top dead center of the rod 5, which contains a rod 5 that can be moved back and forth at the center of the bottom surface where the molding material starts filling the die. A discharge pipe provided with a gate 1 at the contact position of the outer wall in the vicinity) is provided in the upper mold 7, and the molding material is discharged from the gate 1 provided on the upper part of the discharge pipe 4 so as to go around the inner wall of the discharge pipe, After filling the inside of the discharge pipe 4, the inside of the mold cavity 3 (between the upper mold 7 and the lower mold 6) was filled. The gate 1 provided in the discharge pipe 4 is preferably configured to discharge the molding material obliquely upward along the outer periphery of the discharge pipe 4.

  The molding material discharged from the gate 1 having the structure shown in the conceptual cross-sectional view of the molding die 10 of FIG. 1 based on the present embodiment is one of the present inventions. “The gate provided on the discharge pipe is molded. As the material is discharged obliquely upward along the outer periphery of the discharge pipe, the material rises while rotating along the inner wall of the discharge pipe 4. By obtaining this discharge mode, it is possible to avoid the phenomenon that the molding material discharged at high speed collides with the wall surface in the discharge pipe 4 to cause turbulent flow, so that bubbles can be mixed into the mold cavity 3. Since it flows in and avoids remaining in the molded product, the occurrence of blisters and cracks can be suppressed in the subsequent firing stage.

  Furthermore, since the molding material fills the inside of the discharge pipe 4 and then flows into the inner mold at a position corresponding to the center of the bottom of the rice cooker at a very low speed, the mold cavity 3 is filled. Generated turbulence by colliding with the inner wall surface 106a of the lower mold forming the inner wall surface of the molded product opposite to the gate 101, which has occurred in the gate 101, resulting in modulation of the color and gloss of the portion of the molded product. Can be avoided.

  When the injection of the molding material is completed, the rod 5 in the discharge pipe 4 is lowered to push out the molding material remaining in the discharge pipe 4. When the rod 5 in the discharge pipe 4 is lowered by applying a constant pressure, there are many portions where the sharp edges provided in the powder particles obtained by pulverizing graphite receive high discharge pressure and come into contact. It exists and the part retains a large compressive strain. As a result, the obtained molded article exhibits an expansion behavior that releases strain because the holding power of the phenol resin as a binder is reduced in a high-temperature atmosphere that is received during the firing process or the like. Since the expansion behavior is concentrated in a limited area around the graphite particles, fine cracks are likely to occur, and water vapor and unreacted low-molecular-weight raw material residues, which are by-products during polymerization of the phenol resin, are present. Concentrating on the fine cracks creates a problem of generating bubbles by forming bubbles.

  As a means for solving the above-mentioned problem, one of the present inventions is “after the recovery and release of the mold with the primary holding pressure by the rod are repeated until just before the molding material is gelled, the secondary pressure is applied. It is a means based on "maintaining until the mold is opened by taking out the product", and can be solved by repeatedly releasing and recovering the holding pressure before the molding material starts to gel. In other words, the compression deformation at the part where the edges of the graphite particles abut upon receiving the discharge pressure is eliminated by releasing the mold holding pressure to enable the fine movement of the graphite particles, and stable by the recovery of the holding pressure. A minute movement is performed to a position where the contact state is obtained.

  This minute movement is caused by the injection pressure at which the rod 5 is slightly lowered from the completion of the discharge, which is close to 85 seconds of the gelation time in which the viscosity of the molding material suddenly increases in an atmosphere of a molding temperature of 165 ° C., until 70 seconds have elapsed. After applying a higher 10 MPa pressure (primary holding pressure) to the rod 5 and holding it for 1 to 2 seconds, one of the present inventions is “Release of the primary holding pressure after the rod descending in the discharge pipe”. Is performed in a state in which the rod is not driven ", and a step of holding only for 1 to 2 seconds by removing only the hydraulic pressure so that the outside of the rod 5 does not enter and the inside of the molded product wall is not transformed by raising the rod 5 is performed. Repeatedly.

  After releasing the primary holding pressure, the graphite particles can be moved minutely, and by restoring the holding pressure, the graphite particles can have a stable contact state with each other. A state can be secured. As a result, the strain that occurs when the phenol resin as the binder causes a significant decrease in strength in a high-temperature atmosphere such as a baking process in which the heating temperature exceeds the glass transition temperature (Tg) or a heat treatment after molding. It was possible to suppress the generation of fine cracks due to the release behavior and the occurrence of blisters caused by gas concentration in the fine cracks.

  Further, the phenol resin as a binder undergoes curing shrinkage due to gelation, and a tensile stress is applied to the phenol resin to remain inside. This residual stress has a behavior of generating cracks on the wall surface of the molded product and releasing it under a high temperature atmosphere such as a baking process in which a heating temperature equal to or higher than the glass transition temperature (Tg) of the phenol resin is passed or a heat treatment after molding. It will be.

  In particular, immediately below the discharge pipe 4 where the molding material changes its flow direction abruptly, the molding material having a temperature sufficiently lower than that of the mold always flows in a concentrated manner. For example, the temperature of the injected molding material is about 110 ° C., and the temperature of the mold material heated to 165 ° C. is lowered. Compared to the temperature of the molding material in the mold, it will stay without being heated from the mold during the flow, so that the reaction of the molding material in that part will be delayed from other parts. In addition to creating a state where stress accompanying shrinkage tends to concentrate, strain remains, and fine cracks may occur.

  However, one of the present invention after the above-described rod lowering and pressure release is repeated, the 35 MPa applied to the rod 5 based on “maintaining the application of the secondary holding pressure until the mold is released by removing the product”. The pressure holding supplements the stress generated in the wall of the molded product immediately below the discharge pipe 4 where the flow direction of the molding material changes abruptly, and contributes to the suppression of cracking.

  In addition, the molding material which is provided with the discharge pipe 4 and is pushed out as the rod 5 provided inside is lowered is heated during the time until the completion of the injection, and the molding material staying directly under the discharge pipe 4 is excluded. Therefore, it is possible to suppress the delay of the reaction and suppress the concentration of stress generated along with the curing shrinkage.

  The obtained molded product is left in an oxygen-free atmosphere at 1000 ° C. to carbonize the phenol resin to obtain a carbon aggregate molded product. At this time, the decomposition of the phenol resin is activated and the weight is rapidly reduced so that the decomposition gas of the phenol resin generated by the baking treatment is smoothly diffused from the inside of the molded product. The temperature rises and is maintained in the vicinity of. In the present embodiment, the temperature is raised to 300 ° C. at 0.5 ° C./min and then held for 5 hours, and further 5 ° C./hr is 450 ° C., 1 ° C./hr is reached at 500 ° C. and then held for 5 hours. After reaching 750 ° C. at 5 ° C./hr and up to 800 ° C. at 2 ° C./hr, holding for 3 hours, and then reaching 1000 ° C. at 0.5 ° C./min for 2 hours. Thereafter, the mixture was cooled to room temperature at a rate of 5 ° C./min or less to obtain a molded product of a rice cooker.

  At this time, when using a molding material that has a high phenol resin content and fills the voids formed between the particles, organic fibers such as acryl are used by mixing with an extremely small amount of carbon remaining after firing. Is effective. Since these fibers start to be thermally decomposed prior to the phenol resin, innumerable pores are formed, and the gas resulting from the decomposition is easily released. In addition, since the temperature rise rate during the firing process can be accelerated, the cracked gas stays in a small space inside the molded product and expands, and it is effective in suppressing the formation of cracks that break the surface of the molded product in a scaly manner. The temperature rise and holding time can be greatly reduced. Specifically, up to 750 ° C. at 5 ° C./hr, and up to 800 ° C. at 2 ° C./hr, hold for 3 hours, and then at 1000 ° C. at 0.5 ° C./min, hold for 2 hours. In addition, the firing time was shortened by about 2 days without generating defects.

  Next, for use as a rice cooker, silicone resin with excellent wear resistance and heat resistance is blown on the outer surface of the molded product, and fluororesin is blown on the inner surface to prevent adhesion of cooking utensils. I applied and painted. The paint sprayed on the surface provides strong coating film adhesion due to the anchor effect by impregnation filling the voids formed between the particles of the aggregate.

  FIG. 2 is a diagram illustrating the first embodiment, and is a diagram illustrating a comparison result of falling ball impact strength at the bottom center portion of the rice cooker. A maximum of 150 g of steel balls can be dropped to the center of the bottom surface in the vicinity of the discharge pipe 4 or gate 1 of the carbon aggregate molded product of the rice cooker obtained by the above-described means of the present embodiment, without causing cracks. It was confirmed from the measurement result of the falling ball impact strength shown in FIG. 2 that it had the effect of suppressing the extreme decrease in the impact strength indicated by the height.

As shown in FIG. 2, the samples used for measuring the falling ball impact strength are two types (# 1, # 2) for the comparative example and four types (# 1 to # 4) for the present embodiment. The measurement results of other samples will be described with reference to # 4 of the present embodiment, which is the most excellent (no cracking after firing, and no falling ball impact strength is 50 cm).
(1) Since # 1 of the comparative example is different from # 4 of the present embodiment (# 1 of the comparative example is molding material B, # 4 of the present embodiment is molding material A), A crack was generated after firing in the carbon aggregate molded article), and the falling ball impact strength was already cracked at 10 cm.
(2) In the comparative example # 2, the molding material is the molding material A, but no pressure is applied by the discharge pipe 4. Therefore, cracks occurred after baking in the rice cooker (carbon aggregate molded product), and the falling ball impact strength was already cracked at 10 cm.
(3) Compared with # 4 of this embodiment, # 1 of this embodiment does not release and recover pressure. However, cracking did not occur in the rice cooker (carbon aggregate molded product) after firing, and the falling ball impact strength was cracked at 30 cm, but not cracked at 25 cm. It can be seen that it is superior to the comparative examples (# 1, # 2).
(4) Compared with # 4 of the present embodiment, # 2 of the present embodiment has a behavior of additionally charging the molding material driven by the rod 5 at the time of pressure release into the mold. It will not continue until just before conversion. Although # 2 of the present embodiment is effective, the characteristics are the worst among the present embodiments. It can be seen that the rod 5 is not driven when the pressure is released, and that the above-described behavior is performed immediately before the gelation.
(5) Compared to # 4 of the present embodiment, # 3 of the present embodiment does not perform pressurization maintenance after gelation. The falling ball impact strength was 50 cm (the maximum value at which cracking was not possible) of # 4 of the present embodiment, whereas # 3 of this embodiment was 25 cm (maximum value at which it was not cracked).

  The rice cooker obtained through the above steps is built into the rice cooker and has sufficient resistance to the load when it is used for rice cooking with proper control of dielectric heating, for example, the impact strength assuming the dropping of the cooking utensil As well as achieving a significant reduction in the number of man-hours compared to cutting products from conventional graphite blocks, it also made it possible to ensure stable production and quality.

  In the present embodiment, the gate 1 structure provided in the discharge pipe 4 is one of the present inventions such that “the molding material is discharged obliquely upward along the outer periphery of the discharge pipe”. However, instead of this, a means for discharging the molding material upward from the opposing gate 1 may be used. However, it is important to consider that the molding material discharged from the facing position collides to cancel the mutual flow velocity and suppress the mixing of bubbles.

  1 Gate, 3 Mold cavity, 4 Discharge pipe, 5 Rod, 6 Lower mold, 7 Upper mold, 8 Discharge pipe side runner, 9 Mold side runner, 10 Mold, 101 Gate, 103 Mold cavity, 106 Lower mold, 106a Lower mold inner wall surface, 107 Upper mold, 110 Mold.

Claims (8)

Using a die with a discharge pipe with a gate at the contact point on the outer wall near the top dead center of the inner rod located on a substantial portion of the bottom center outer wall of the pot-shaped molded product, mainly composed of carbon powder and phenol resin It is a shaping method by injecting molding material and heating and pressurizing,
A method for molding a carbon particle composite resin, wherein the rod is lowered and pressurized immediately after injection, and then the pressure is released and further recovered.   The method for molding a carbon particle composite resin according to claim 1, wherein the gate provided in the discharge pipe discharges the molding material in an obliquely upward direction along the outer periphery of the discharge pipe.   The method for molding a carbon particle composite resin according to claim 1, wherein release of the primary holding pressure after the rod descending in the discharge pipe is performed in a state where the rod is not driven.   The recovery and release at the primary holding pressure of the mold by the rod is repeated until just before the molding material is gelled, and then the addition of the secondary holding pressure is maintained until the mold is opened by taking out the product. A method for molding a carbon particle composite resin according to any one of claims 1 to 3.   5. The carbon powder composite according to claim 4, wherein the primary holding pressure is higher than the injection pressure and sufficiently lower than the secondary holding pressure, and is accompanied by a compression behavior due to the lowering of the rod. Resin molding method.   The molding material comprises a carbon particle coated with an uncured phenol resin obtained by polymerizing a compound containing a phenol group and a compound containing an aldehyde group in water in the presence of a surfactant, and a phenol resin that forms a liquid at a molding temperature. A method for molding a carbon particle composite resin according to any one of claims 1 to 5, wherein a mixture of   The method for molding a carbon particle composite resin according to claim 6, wherein the surfactant exhibits a polymer electrolyte behavior and forms a polyion complex with a phenol resin in a polymerization process.   The method for molding a carbon particle composite resin according to claim 6, wherein the molding material is used by mixing organic fibers having a decomposition start temperature lower than that of a phenol resin and a low carbon residual ratio in the firing stage.

Images