JP5225326B2 - 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.

  As mentioned above, in order to form a rice cooker by injection molding without forming a weld, it is important to make the molding material flow at the same time to reach the outer periphery of the flange at the top of the rice cooker. Most preferably, a gate is provided at the center of the bottom of the product.

  However, since the molding material discharged from the gate collides with the opposing inner wall surface and locally generates turbulence, the color and gloss of the part of the molded product are modulated. In addition, when a large-diameter gate that reduces the collision speed is provided, a lot of work is required to process the gate, and cracks occur in the molded product layer due to the gate cutting load in the mold. This causes the problem of

  Also, at the center of the bottom surface where the gate is located, the lower mold that collides with the molding material melted at a temperature lower than the mold temperature is locally cooled and the final filling convects. There was a problem that the tensile stress of hardening shrinkage accompanying the delay was concentrated and the internal stress was accumulated, leading to generation of cracks and extreme deterioration of physical properties.

  As a means of raising the temperature of the molding material to be concentrated and charged at a specific position so as to approximate the mold temperature, for example, when injection molding the molding material, the sprue and runner temperature is higher than the normal sprue and runner temperature. By further increasing the ratio, the reaction proceeds before the molding material containing the melamine resin enters the cavity, the heat generation in the gate is increased, and a means for shortening the curing time is disclosed (for example, patent document) 4).

  In addition, after filling the mold cavity with resin, the injection pressure is continuously increased, so there are no burrs or sink marks on the surface of the molded product, air bubbles inside the molded product, stress unevenness, etc. Means for obtaining the molded article is disclosed (for example, see Patent Document 5).

JP-A-9-75211 JP-A-9-70352 JP 2007-44257 A JP 07-164470 A Japanese Patent Laid-Open No. 61-227010

  However, in the case of the injection disclosed on the premise of the melting temperature of the molding material in view of the fact that the sprue of the molding material and the passage time of the runner are assumed to be very short from the injection time. It is difficult to expect a sufficient temperature rise that can approximate the temperature of the mold to the mold temperature, and the nozzle in contact with the mold in order to suppress the backflow of the molding material from the mold, The problem is that the molding material remaining inside hardens and prevents the next discharge. In addition, what is disclosed in Patent Document 5 described above is an internal structure based on deformation of a portion where the fillers abut when the filling pressure in the molding of the composite material in which the irregular fillers are mixed is maintained. Residual stress causes a problem of inducing defects such as cracks as the stress is released in a temperature range equal to or higher than the glass transition point of the resin.

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.

Method of forming carbon powder particle composite resin according to the present invention is a molding die of the pot-shaped molded article, in positions corresponding to the outer bottom center of the pot-shaped molded article, the gate has a rod on the inner side upward the molding die provided with a discharge pipe that is distribution to the inner circumferential surface, a compound comprising a compound and an aldehyde group containing phenolic groups is surface by existing phenolic resin uncured material polymerized in water of the surfactant coated and a carbon powder particles, a method of forming carbon powder particle composite resin for shaping Ri by the heat and pressure of the mixture der Ru molding material injected into the phenolic resin forms a liquid at the molding temperature, from the gate immediately after injection of the molding material lowers the rods, after temporarily releasing the holding pressure of the mold after lowering of the rod, it is the also Ru restored the holding pressure of the forming metal mold.

  The method for molding the carbon particle composite resin according to the present invention is such that, on the inner mold surface of the portion corresponding to the center of the inner surface of the pot-shaped molded article of the molding die, the deterioration of the design due to the fixation of the graphite particles and the wear of the mold, It was possible to suppress the occurrence of cracks and deterioration of physical properties in the molded product layer.

  In addition, 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 end portion in the portion where the end portion having an acute shape of graphite particles contacted was deformed and compressed. From the state where stress remains, a dense filling state where a stable flat surface abuts is secured to prevent deformation when the molded product is heated, and the part where the low-temperature raw material is concentrated on the part is diffused. As a result, it was possible to suppress the occurrence of cracks and a decrease in impact strength due to residual stress due to reaction delay.

FIG. 3 is a diagram showing the first embodiment, and is a conceptual cross-sectional view of a molding die 10 (a die structure of a gate 1 and a discharge pipe 4 portion). FIG. 3 is a diagram illustrating the first embodiment and is a conceptual cross-sectional view in the vicinity of the gate 1; 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, in order to ensure the appearance design of the molded product, after uneven distribution of density distribution and mold filling It is necessary to control the flow of the molding material in the mold so that the secondary flow depending on the distribution of the injection pressure does not occur. For this reason, the molding material has a working time required for holding in the molding machine and a suitable reaction rate that can suppress an excessive increase in fluid viscosity. In the case of a rice cooker, L / T is large and thin molding is performed. Because it is a product, it is difficult to control the flow.

  Note that L / T has a flat portion having a constant thickness, the thickness of the flat portion being T, and the ratio between the end of the flat portion furthest away from the gate and the distance between the gate is L. Say.

  Further, in order to obtain a flow form that does not form a weld, the molding means for injecting from the gate installed at the center of the bottom surface so that the molding material reaches the entire circumference of the flange at the same time, the molding material discharged from the gate, It collides with the opposing inner wall surface and locally generates turbulence. For this reason, the gate diameter expansion to avoid the modulation and color tone and gloss of the part requires a lot of labor to process the gate part of the molded product, and gate cutting in the mold In this case, there is a problem that cracks occur in the inner layer portion of the molded product that receives an excessive load.

  Also, at the center of the bottom surface where the gate is located, the part where the molding material lower than the mold temperature collides is locally cooled and the final filling stays. There was a problem that tensile stress was concentrated and internal stress was concentrated, leading to generation of cracks and extreme deterioration of physical properties.

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

  That is, by filling the mold cavity with the molding material temporarily held and heated in the discharge pipe, the mold temperature is approximated, and the molding material at the final filling position is made to flow at a low speed so that the bottom Excluded from the central position. Thereafter, the strength was improved by pressurization centered on the molding material retained in the center of the bottom surface.

  The mold for injection molding that enables this behavior consists of a cylindrical discharge pipe in which a molding material is filled into a mold with a rod built in, and the molding material discharged from the gate provided above the discharge pipe is the discharge pipe. After that, the inside of the mold cavity was filled. At this time, the discharge pipe having a diameter larger than that of the gate is filled to reduce the inflow speed into the cavity, and the molding material remaining inside is pushed into the mold cavity to apply pressure to the molded product. I did it.

  Further, by repeatedly applying and releasing pressure to the rod in the pressure application stage of the discharge pipe, it is possible to avoid excessively holding the distortion by contacting the edges of the graphite grains having a high content rate. I made it.

  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.

  By configuring in this way, it is possible to avoid deterioration of design properties due to adhesion of graphite powder particles on the inner mold surface and wear of the mold, crack generation in the local area and deterioration of physical properties at a portion corresponding to the inner central portion of the rice cooker. It was.

  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, cracking and reduction in impact strength due to residual tensile stress accompanying the delay of the reaction of the part were suppressed, injection molding Since the dense filling state is ensured while returning the deformation due to the contact between the graphite particles of the product to the original shape, homogenization of the molded product was achieved.

  This is a means of obtaining a pot-shaped molded product by injection molding, which uses a molding material consisting of graphite powder and a phenolic resin as a binder to mold an inner pot of a rice cooker that is a pot-shaped molded product. A method for molding a carbon powder composite resin (a method for producing an electromagnetic induction heating cooker), which is a coagulated product obtained by baking at a high temperature in an oxygen atmosphere, will be described in detail below.

  The molding material is phenol, quaternary, which is obtained by calcining petroleum coke at an oxygen-free high temperature (3000 ° C.) and then pulverizing the graphite lump to 0.1 mm or less into graphite granules. An ammonium salt type cationic activator is added as a surfactant, and formaldehyde is added and polymerized while stirring so as to uniformly disperse graphite powder while heating to 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 graphite powder has a coating amount of 25 wt%, and the obtained molding material A is 40 ° C. or less. The low-pressure drying treatment was performed at a 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 used by mixing organic fibers having a lower decomposition start temperature 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 is in a state in which the surface of the graphite powder is always wet with the raw material liquid for polymerizing the phenol resin, so that a resin thin film is formed on the outer surface of the graphite powder, It was obtained as a forming raw material held as a binder for the graphite powder.

  In addition, the molding material B used as a comparative example includes a mixture of graphite powder obtained by pulverizing a lump of petroleum coke fired at an oxygen-free high temperature (3000 ° C.) and a novolac phenol resin. : A mixture with a ratio of 25 was used. The mixture was obtained by dissolving a phenol resin in alcohol and the like, kneading while spraying on graphite in a kneader, and then drying.

  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 said subject can be eliminated by using the molding material pressure granulated to about 1-3 mm.

  Next, the molding material (molding material A, 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 was obtained by injecting and pressurizing, demolding after holding as a curing time of 3 minutes, and obtaining.

  At this time, the pressure at the time of injection of the molding material B which is a mixture of an uncured phenolic resin having a low melting point and graphite particles was 10.5 Mpa, whereas the molding material A according to the present embodiment is Filling in the mold was completed at a low pressure of 7.5 MPa. This is because when the molding material A fills the mold, graphite powder particles coated with uncured phenol resin on the surface have rounded sharp edges formed by crushing. This is due to the fact that it is difficult to agglomerate due to the pressure accompanying flow with melting.

  1 and 2 are diagrams showing the first embodiment. FIG. 1 is a conceptual cross-sectional view of a molding die 10 (mold structure of a gate 1 and a discharge pipe 4 portion), and FIG. FIG.

  As shown in FIG. 1, the molding material melted in the injection molding machine (molding mold 10) is filled into a mold cavity 3 that is shaped into an inner hook shape from a gate 1 through a discharge pipe 4. The mold cavity 3 is formed between the inner mold 6 and the outer mold 7. Although not shown, the mold cavity 3 has a rice cooker shape. The discharge pipe 4 is located in the substantially center part of the bottom outer surface of the rice cooker. The discharge pipe 4 includes a rod 5 that can freely move forward and backward. The inner periphery of the discharge pipe 4 is defined as a discharge pipe inner wall surface 4a.

  FIG. 4 is a view for comparison, and is a conceptual diagram of a conventional molding die 110 (near the gate 101). As shown in FIG. 4, the mold structure at the center of the bottom surface where the molding material in the conventional molding die 110 is filled into the mold cavity 103 is formed from the gate 101 disposed on the bottom outer surface (outer die 107). It was the structure discharged toward the inner surface (inner mold inner wall surface 106a of the inner mold 106). For this reason, the molding material discharged from the gate 101 flows into the mold cavity 103 after colliding with the inner mold 106 at a high speed.

  That is, in the conventional molding die 110 shown in FIG. 4, since it is essential to flow from the bottom center of the rice cooker toward the flange portion, the gate installed at the position opposite to the corresponding portion at the center of the rice cooker inner surface. Since the molding material discharged at a high speed from 101 collides with the inner mold inner wall surface 106a, there is a problem that it is easy to cause deterioration in designability and damage to the mold due to adhesion of graphite particles and wear due to wear on the mold surface. Have

  On the other hand, if the gate 1 of the molding die 10 according to the present embodiment is used, as shown in FIG. 1, the molding material discharged at a high speed from the gate 1 is discharged after colliding with the inner wall surface 4a of the discharge pipe. Since the speed is drastically decreased and the inside of the mold cavity 3 is filled, the above-mentioned problem does not occur.

  As shown in FIGS. 1 and 2, the molding die 10 according to the present embodiment is such that the molding material discharged from the gate 1 formed on the side surface of the discharge pipe 4 is the molding material injected from the gate 1. 4 is discharged. Then, the molding material collides with the inner wall surface 4a of the discharge pipe and fills the inside to reach the inner mold 6 at a position corresponding to the center of the bottom of the rice cooker at a very low speed, and the mold cavity 3 is slightly unfilled. It is filled leaving a part. Next, immediately after the completion of the injection, the rod 5 in the discharge pipe 4 is lowered, the molding material remaining inside is poured into the mold cavity 3, and then the curing is completed to shape the rice cooker. To do.

  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 is in a state of holding a large compressive strain. As a result, the obtained molded article exhibits an expansion behavior that releases strain at a temperature higher than the glass transition temperature at which the holding power as a binder is reduced in a high temperature state that is received during the firing process.

  The expansion behavior is uneven and concentrates in a limited area around the graphite particles, so that fine cracks are likely to occur. As a result, water vapor, which is a by-product during polymerization of the phenol resin, and the residue of unreacted low molecular weight raw materials concentrate on the fine cracks, forming bubbles and expanding the cracks to generate blisters. Create challenges.

  As a means for solving the above-mentioned problems, the present invention “recovers and releases the mold by the primary holding pressure by the rod repeatedly until just before the molding material gels, and then adds the secondary holding pressure to the mold by removing the product. This can be solved by repeatedly releasing and recovering the holding pressure before the start of gelation of the molding material, based on "Maintaining until mold opening".

  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 less than the injection pressure at which the rod slightly drops from the completion of discharge, which is close to 85 seconds of the gelation time in which the viscosity of the molding material rapidly rises in an atmosphere of a molding temperature of 165 ° C., after 70 seconds. After applying a high 10 MPa pressure (primary holding pressure) to the rod 5 and holding it for 1 to 2 seconds, the release of the primary holding pressure after the rod descending in the discharge pipe of the present invention does not drive the rod. Based on “Perform in a state”, the step of holding only for 1 to 2 seconds by removing only the hydraulic pressure was repeatedly performed so that the outside of the rod 5 would not enter and the inside of the molded product wall would not be transformed.

  After enabling the fine movement of the graphite particles when releasing the primary holding pressure, the recovery of the primary holding pressure enables the graphite powder particles to have a stable contact state with each other. The contact state can be secured. According to the present invention, “the recovery and release of the mold with the primary holding pressure 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”. As a result of performing the process based on the condition, 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 of the strain generated in the above 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, 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 stays without being heated from the mold during the flow, so that the reaction of the molding material in the part is delayed from the other part. As a result, the stress caused by the shrinkage tends to concentrate, and the strain remains, and the occurrence of fine cracks may occur.

  However, after the above-described repeated lowering of the rod 5 and release of the pressure, “recovery and release of the mold at the primary holding pressure by the rod is repeated until just before the molding material is gelled, and then the secondary holding. Maintaining the pressure of 35 MPa on the rod 5 based on “maintaining the pressure application until the mold is opened by taking out the product” means that the stress generated in the molded product wall immediately under the discharge pipe where the flow direction of the molding material changes rapidly. Supplement and contribute to the prevention of cracks.

  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 becomes active 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 at 450 ° C. at 5 ° C./hr and at 500 ° C. at 1 ° C./hr 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 begin to thermally decompose prior to the phenolic resin, they can form numerous pores, facilitating the release of gas resulting from the decomposition of the resin, and the rate of temperature rise during the firing process can be accelerated. The cracked gas stays in a small space inside the product and expands, and it is effective in suppressing the formation of cracks that destroy the surface of the molded product. In addition, the conventional 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. 3 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. 3 that it had the effect of suppressing the extreme decrease in impact strength indicated by the height.

As shown in FIG. 3, the samples used for measuring the falling ball impact strength are two types (# 1, # 2) for the comparative example and four types (# 1- # 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 of 55 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, cracks did not occur after firing in the rice cooker (carbon aggregate molded product), and the falling ball impact strength was cracked at 35 cm, but not cracked at 30 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 driving of the rod 5 at the time of pressure release and the continuous execution until just before the gelation of the above behavior are effective.
(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 55 cm (maximum value that does not break) of # 4 of this embodiment, and # 3 of this embodiment was 30 cm (maximum value that does not crack).

  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.

  According to the present embodiment, on the inner mold surface corresponding to the center of the inner surface of the rice cooker of the injection mold, deterioration of designability due to fixation of graphite particles and wear of the mold, generation of cracks in the molded product layer And physical property deterioration could be avoided.

  In addition, since the molding material was discharged while repeating the pressurization and release of the discharge pipe held at a high temperature immediately after the injection, the end portion at the portion where the end portion having an acute shape between the graphite particles contacted was deformed. From the state in which compressive stress remains, a dense filling state where a stable flat surface abuts is secured to prevent deformation of the molded product during heating, and the portion where the low-temperature raw material is concentrated and diffused in that part is diffused As a result, it was possible to suppress the occurrence of cracks due to residual stress due to reaction delay and the reduction in impact strength.

  1 gate, 3 mold cavity, 4 discharge pipe, 4a discharge pipe inner wall surface, 5 rod, 6 inner mold, 7 outer mold, 10 molding mold, 101 gate, 103 mold cavity, 106 inner mold, 106a inner mold inner wall surface 107 Outer mold, 110 Mold.

Claims (4)

A molding die of the pot-shaped molded article, in positions corresponding to the outer bottom center of the pan-shaped molded article, comprising a discharge pipe having a gate having the inner side above was distribution on the inner peripheral surface of the rod shaped the mold, phenolic compound comprising a compound and an aldehyde group containing phenolic groups is formed between the carbon powder particles whose surface is covered by existing phenolic resin uncured material polymerized in water of the surfactant, the liquid at the molding temperature in the molding method of a carbon powder particle composite resin for shaping Ri by the heat and pressure of the mixture der Ru molding material injected into the resin,
It said rod lowering the immediately injection of the molding material from the gate, after temporarily releasing the holding pressure of the molding die after lowering of the rod, to restore the holding pressure of the previous SL molding die Turkey And a method for molding a carbon powder composite resin. When temporarily release the holding pressure of the molding die after drop before Symbol rod, forming the carbon powder particle composite resin according to claim 1, characterized in that to maintain the state not to increase the rod Method. Lowering the said rod, after temporarily releasing the coercive Ji圧of the molding die after lowering of the rod, the step of restoring the holding pressure of the molding die, repeated until gelation immediately before the molding material and then, according to claim 1 or claim and maintains the state by adding a predetermined holding pressure to the molding die, until the molding die opening of Sutame Eject the pot-shaped molded article 2. A molding method of the carbon particle composite resin according to 2. The method for molding a carbon particle composite resin according to claim 3 , wherein a holding pressure of the molding die in the step is higher than an injection pressure of the molding material and lower than the predetermined holding pressure.

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