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

Molding method of carbon powder composite resin Download PDF

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JP5020351B2
JP5020351B2 JP2010114992A JP2010114992A JP5020351B2 JP 5020351 B2 JP5020351 B2 JP 5020351B2 JP 2010114992 A JP2010114992 A JP 2010114992A JP 2010114992 A JP2010114992 A JP 2010114992A JP 5020351 B2 JP5020351 B2 JP 5020351B2
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芳夫 西本
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Description

本発明は、電磁誘導加熱が可能な炊飯釜などに使用するカーボン粉粒複合樹脂の成形方法に関する。カーボン粉粒と高炭素含有物質である結合材を主体とするカーボン粉粒複合樹脂の射出成形に用いる金型構造に特徴があるものである。   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.

誘導加熱コイルの渦電流による電磁誘導加熱を利用したコンロや炊飯器は、磁性金属にアルミニウムや銅などの高熱伝導金属を積層したクラッド材の成形品が主流である。しかし、クラッド材は、鍋や釜などの形状に加工することが困難であるうえ、フッ素樹脂などの耐熱樹脂塗装面との界面で剥離し易いという課題があった。   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.

このため、従来の電磁誘導加熱の素材に代えて、優れた導電性と伝導度を有するカーボン凝結体の使用することが提案されている(例えば、特許文献1参照)。   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).

また、コークスなどのカーボン粉粒と結合材であるフェノールやピッチなどの高炭素含有物との混合物を棒柱状に加圧して成型したものを無酸素雰囲気下の1000〜3000℃で加熱して得たカーボン凝結体とし、これを炊飯釜などの調理器具に切削加工したものが、高温での調理器具として有効であることが開示されている(例えば、特許文献2参照)。   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).

上述の調理器具の製造方法によれば、カーボン焼結体を切削加工の大半を占める凹状容器の中空部分にある素材の廃棄が多く、加工工数も大きい、という課題があった。さらに、カーボン圧縮体の欠陥の内在を事前に検知することが困難なうえ、切削によって露出するなどによって意匠および強度などに悪影響を及ぼし、使用できないこともあった。   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.

これらの課題を解決する手段として、カーボンの粉粒とフェノール樹脂の原料液やタールピッチなどの結合材との混合物である成形材料を金型内に注入して加圧して賦型した後、得られた成形品を焼成処理することにより、鍋状に成形されたカーボン凝結体を得る手段が提案されている(例えば、特許文献3参照)。   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).

しかし、電磁誘導加熱が可能な調理器具として使用するうえで必要な強度、電気伝導、熱伝導に優れた特性を備えたカーボン凝結体成形品を得るためには、成形材料のフェノール樹脂含有量を少なくすることが必須である。反面、カーボン粉粒表面が十分な濡れを有しないために凝集し易く、見掛けの粘度が向上して流動性が低下すると共に、流動の先端が合流するウエルド部分は剛直な筋状として意匠上の欠陥が認められ、強度の低下とともに成形品の壁面としての均質性が喪失し易いという課題があった。   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.

特開平9−75211号公報JP-A-9-75211 特開平9−70352号公報JP-A-9-70352 特開2007−44257号公報JP 2007-44257 A

上述の如く、ウエルドを形成することなしに射出成形による炊飯釜の成形を行うには、炊飯釜の上部にあるフランジの外周に成形材料が同時に到達する流動形態を確保することが肝要で、成形品の底面中央部分にゲートを設けることが最も好適である。しかし、ゲートから吐出した成形材料は、ゲートに相対する成形品内壁面を形成する内金型表面に衝突して乱流を生じ、成形品の当該部分の色や光沢に変調を来す。また、衝突速度を緩和する大口径のゲートを設けた場合には、ゲート切断部分の処理に多くの手間を要するほか、金型内でのゲート切断の負荷を受けて成形品壁内に亀裂発生を来す、という不具合を生じる。   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

また、ゲートが位置する底面中央部では、金型温度より低温度の溶融状態を成す成形材料が下金型に衝突して冷却した局部に最終の充填物が滞留するので、周辺部より反応が遅延して硬化収縮によって発生する引張応力が集中して内部応力を蓄積し、クラックの発生や物性の極端な低下を招く、という課題を有していた。   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.

この発明は、上記のような課題を解決するためになされたもので、以下に示す事項を目的とするカーボン粉粒複合樹脂の成形方法を提供する。
(1)射出成形金型の鍋状成形品の底面中央に相当する部位の内型表面において、黒鉛粉粒の固着や金型の摩耗による意匠性の低下、成形品層内におけるクラック発生や物性低下を回避する。
(2)ゲート近傍における反応遅延に起因する応力残留に伴うクラック発生や衝撃強度の低下を抑止する。
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.

この発明に係るカーボン粉粒複合樹脂の成形方法は、内在するロッドの上死点近傍外壁の接点位置にゲートを設けた吐出管を、鍋状成形品の底面中央外壁の相当部分に配した金型を用い、カーボン粉粒とフェノール樹脂を主体として成る成形材料を注入して加熱・加圧による賦形方法であって、
射出直後にロッドを降下させて加圧させた後、圧力を解放、さらに回復させるようにしたことを特徴とする。
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.

この発明に係るカーボン粉粒複合樹脂の成形方法は、射出直後にロッドを降下させて加圧させた後、圧力を解放、さらに回復させるようにしたので、成形品の底面中央部における反応遅延に起因した低温の成形材料を分散するとともに、当該部分の収縮挙動を圧縮応力の付加によって面方向の引っ張り歪みの発生が低減した。それにより、クラック発生や衝撃強度の低下を抑止して、射出成形品の黒鉛粒子同士の当接部分における変形が本来の形状に戻されながら密な充填状態を確保して成形品の均質化を達成できた。   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.

実施の形態1を示す図で、成形金型10の概念断面図。FIG. 3 is a conceptual cross-sectional view of a molding die 10 showing the first embodiment. 実施の形態1を示す図で、炊飯釜の底面中央部における落球衝撃強度の比較結果を示す図。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. 比較のために示す図で、従来の成形金型110(ゲート101近傍)の概念図。It is a figure shown for a comparison and is a conceptual diagram of the conventional molding die 110 (the gate 101 vicinity).

実施の形態1.
以下、この発明を実施するための形態の一例を説明する。本実施の形態は、カーボン粉粒複合樹脂の成形方法(ゲート遮断と圧縮機能を備えた射出成形ゲートの構造)に関する。先ず、実施の形態1の概要について説明する。
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.

黒鉛粉粒の含有率が高いフェノール樹脂との混合物を用いてL/Tの大きな薄肉成形品の射出成形を行う際に、前記混合物である成形材料の粘度が極めて高く、流動性に劣るために成形品の密度分布が大きい、という課題を有する。特に、炊飯釜のような鍋状の成形品では、ウエルド部分の強度低下と過度な残留応力の抑制に加え、金型充填後の圧力分布に依存した二次流動に起因する成形品外観の意匠性損失を抑止するために、成形材料の金型内における流動制御が必須である。このため、成形材料には成形機(成形金型)内で滞留による流動粘度の過度な上昇を抑制しうる好適な反応速度を備える。   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).

しかし、炊飯釜はL/Tが大きいうえに薄肉成形品であるため、ウエルドを形成しないフランジ全周に成形材料が同時に到達するよう、底面中央部に設置したゲートから射出する成形手段の採用が必須となる。しかし、従来のゲート形状では、吐出した成形材料が相対する内壁面に衝突して局部的に乱流を生じさせるため、当該部分の表面粗度に変調を来して外観意匠を悪化させる。これを避けるためのゲート口径を拡大したゲートの適用は、金型内でのゲート切断の際に過度な負荷を受けた成形品の内層部分に亀裂が発生するほか、残痕除去処理に多くの手間を要するという不具合を生じる。   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.

尚、L/Tは、一定の厚みの平面部を有し、この平面部の厚みをTとし、ゲートから最も離れた該平面部の末端と該ゲート間の距離をLとしたときの両者の比を言う。   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.

また、ゲートが位置する底面中央部では、金型温度より低温の成形材料が衝突する底部中央内面部分が局部的に冷却されるとともに最終の充填物が滞留するので、周辺各部より反応遅延に伴う硬化収縮の引張応力が集中して引っ張り応力が集中し、クラックの発生や物性の極端な低下を招く、という課題を有していた。   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.

フェノール樹脂に黒鉛粉粒を高い含有率で混合した成形材料を用いた射出成形品を焼成処理して得る誘電加熱の発熱効率が高いカーボン凝結成形品を得る成形金型において、前記成形材料の吐出位置に相当する成形品の底部中央相当位置に、以下に示す構造を備えたゲートを設けて上記課題を解消する。   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.

つまり、金型キャビティに成形材料を低速で充填すると供に一時的に保持して加温することによって金型温度に近似させ、これを流入させて最終充填位置にある成形材料を底部中央位置から排除する。さらに、該部分を中心に加圧することによって強度の向上を達成させるようにした。   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.

上記目的を達成させるため、射出成形用金型は、成形材料が金型に充填を開始する底面中央部分にロッドを内蔵する円筒状の吐出管を設けて成り、前記吐出管上部の吐出管接点位置に設けたゲートから成形材料を吐出管内壁を周回するように吐出して、吐出管を経て金型キャビティ内を充填するようにした。この結果、吐出管からキャビティ内への流入速度を大幅に抑制すると共に、吐出完了後に残留して加温された前記成形材料を、ロッドを降下させることによって金型キャビティに押し出して底部中央位置にある低温の成形材料を排除するとともに、成形品に圧力を付加するようにした。   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.

さらに、上述の圧力付加段階で、ロッドには圧力の付加と解放を繰り返して、高い含有率を備えた黒鉛粒の端辺同士が当接して過度に歪みを備えた状態で保持することを回避した。   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.

以上、一連の金型駆動を含む成形材料の射出完了から硬化完了まで、金型と吐出管は保持圧と温度を保持し、この段階が完了した後に金型を開放して射出成形品を取り出すことになる。   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.

炊飯釜内面中央部に相当する部位で内金型(下金型)面における黒鉛粉粒の固着や金型の摩耗による意匠性の低下、残存する歪みの解放によるクラック発生または前記歪みに基づく残留応力による物性低下を回避できた。   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.

一方、射出直後に高温保持した吐出管の加圧と解放を繰り返しながら成形材料を排出したので当該部分に滞留している比較的低温で他の部位に比較して反応が遅延して硬化収縮に伴う歪みが集中し易い成形材料を排除、分散させたので、クラックの発生や衝撃強度低下を抑制し、射出成形品の黒鉛粒子の鋭角な角の当接を回避して安定した当接状態を確保して密な充填状態を確保するので、成形品の均質化を達成することができた。   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.

射出成形によって鍋状の成形品を得る手段であって、黒鉛粉粒と結合材であるフェノール樹脂との混合物が原料である成形材料を用いた鍋状の成形品である炊飯器の内釜成形品を、無酸素雰囲気下で焼成処理して得る電磁誘導加熱調理器の製造方法について、以下に詳述する。   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.

成形材料は、石油コークスを無酸素状態の高温(3000℃)で焼成処理して0.1mm以下に粉砕した黒鉛粉粒、水で希釈したフェノール、界面活性剤として第四級アンモニウム塩型カチオン活性剤を加え、任意温度下で黒鉛粉粒が均一分散するように撹拌しながらホルムアルデヒドを添加して重合させたものである。   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.

反応時の温度と時間を調整して任意重合度を成す半硬化フェノール樹脂が、カーボン粉粒物の表面に25wt%の被覆量になるようしたものであり、得られた成形材料Aは40℃以下の低温で減圧乾燥処理を行った。   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.

界面活性剤には、例えば、高分子電解質挙動を示して重合過程のフェノール樹脂とポリイオンコンプレックスを形成したものを用いる。   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.

尚、成形材料は、フェノール樹脂より分解開始温度が低く、焼成段階でカーボン残存率が少ない有機繊維を混合して用いるものでもよい。   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.

以上の方法によって得られた未硬化状態のフェノール樹脂は、カーボン粉粒物の表面がフェノール樹脂を重合する原料液で常に濡れた状態で重合したので、カーボン粉粒の外周面に膜として保持されて成る粒状の成形用原料として得た。   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.

また、比較例として、上述の黒鉛粉粒とノボラック系フェノール樹脂との混合物を、75:25の割合で混合したものを用いた。混合物は、フェノール樹脂をアルコールなどに溶かし、混練機内で黒鉛に噴霧しながら混練した後、乾燥することによって得た成形材料Bを用いた。   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.

また、黒鉛粉粒には多くの微粉末を含んでいるうえ、破砕によって形成した鋭角な端辺が当接して固着し易いので、射出成形機内の回転するスクリューの溝内で混練する際に凝集してスクリュー内に滞留し、計量が困難な状況に陥る。このため、黒鉛粉粒は、100〜300μmに粒径を揃えたものを用いることにより、前記課題の解消が可能となる。   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.

次に、該成形用原料(成形材料A並びに成形材料B)をシリンダー温度が60℃、ノズル温度が110℃、金型温度が165℃の射出成形条件にて金型外周面に設けたゲート部(ゲート)から射出して加圧し、3分間の硬化時間として保持後に脱型して、成形品(本実施の形態、比較例)を得た。   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.

このとき、低融点のフェノール樹脂と混合した成形材料Bの射出時圧力が10.5Mpaであったのに対し、本実施の形態に係る成形材料Aは、7.5MPaの低圧で金型充填を完了した。これは、成形材料Aが金型内を流動する際に、黒鉛粉粒表面に未硬化のフェノール樹脂を被覆したことによって、黒鉛粉粒が破砕により形成した鋭角な端辺が丸みを帯びて、前記フェノール樹脂の溶融とともに流動に伴う圧力によって凝集し難いので、流動性が向上したことによる。   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.

図3は比較のために示す図で、従来の成形金型110(ゲート101近傍)の概念図である。射出成形機(成形金型)内で溶融した成形材料は、内釜成形品を賦形する金型キャビティ内を充填する。このとき、炊飯器内釜を成形する成形材料を金型キャビティ内に充填する底面中央位置における従来の成形金型110の構造は、図3に示すとおりである。   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.

従来の成形金型110は、上金型107表面にゲート101を配して吐出する構造であるが、ゲート101から吐出した成形材料は高速で下金型106の下金型内壁面106aに衝突した後、金型キャビティ103内を流動することになる。   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.

そのため、従来の成形金型110では、ゲート101から吐出した成形材料は、ゲート101に相対する成形品内壁面を形成する下金型内壁面106aに衝突して乱流を生じ、成形品の当該部分の色や光沢に変調を来す。   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.

また、ゲート101が位置する底面中央部では、金型温度より低温度の溶融状態を成す成形材料が下金型106に衝突して冷却した局部に最終の充填物が滞留するので、周辺部より反応が遅延して硬化収縮によって発生する引張応力が集中して内部応力を蓄積し、クラックの発生や物性の極端な低下を招く、という課題を有していた。   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.

図1は実施の形態1を示す図で、成形金型10の概念断面図である。成形金型10(射出成形用金型)は、成形材料が金型に充填を開始する底面中央部分に進退自在なロッド5を内蔵する円筒状の吐出管4(内在するロッド5の上死点近傍外壁の接点位置にゲート1を設けた吐出管)を上金型7に設けて成り、吐出管4上部に設けたゲート1から成形材料を吐出管内壁を周回するようにして吐出して、吐出管4内部を充填した後に金型キャビティ3(上金型7と下金型6との間)内を充填するようにした。尚、吐出管4に設けたゲート1は、成形材料を吐出管4の外周に沿って斜め上方向に吐出する構成であることが好ましい。   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.

本実施の形態に基づく図1の成形金型10の概念断面図で示す構造を成したゲート1から吐出する成形材料は、本発明の一つである、「吐出管に設けたゲートが、成形材料を吐出管の外周に沿って斜め上方向に成形材料を吐出する」に基づいて、吐出管4の内壁に沿って回転しながら上昇する。この吐出の態様を得たことにより、高速で吐出した成形材料が吐出管4内で壁面に衝突して乱流を来す現象が回避できるので、気泡を混入した状態で金型キャビティ3内へ流入して成形品内への残留を回避するので、後段の焼成段階でフクレや亀裂の発生を抑止することができる。   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.

さらに、成形材料は吐出管4内を埋めた後、炊飯釜の底面中央部に相当する位置の内型に極めて遅い速度で流入して金型キャビティ3内を充填することになるので、従来のゲート101で発生していた「ゲート101に相対する成形品内壁面を形成する下金型内壁面106aに衝突して乱流を生じ、成形品の当該部分の色や光沢に変調を来す」という課題を回避することができる。   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.

成形材料の射出が完了した段階で、吐出管4内のロッド5を降下させて、吐出管4内に残留する成形材料を押し出す。この吐出管4内にあるロッド5の降下は、定圧を付与して降下させた場合、黒鉛を粉砕して得た粉粒が備える鋭角な端辺が高い吐出圧を受けて当接する部位が多く存在して、該部分が大きな圧縮歪みを保持することになる。この結果、得られた成形品は、焼成過程などで受ける高温雰囲気で結合材であるフェノール樹脂の保持力が低下するので、ひずみを解放する膨張挙動を来す。前記膨張挙動は、黒鉛粉粒周辺の限られた部位に集中するので、微細な亀裂が発生しやすく、フェノール樹脂の重合時の副生成物である水蒸気や未反応の低分子量原料の残留物が前記微細亀裂に集中して、気泡を形成してフクレを発生させる、という課題を生む。   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.

前記課題を解決する手段として、本発明の一つである、「ロッドによる金型の一次保持圧での回復と解放が、成形材料のゲル化直前まで繰り返し行った後、二次圧の付加を製品取り出しによる金型開放時まで維持する」に基づいた手段であって、成形材料のゲル化開始以前に保持圧の解放と回復を繰り返し行うことにより解消できる。つまり、吐出圧を受けて黒鉛粒子の端辺が当接する部位の圧縮変形を、金型保持圧の解放によって解消して黒鉛粉粒の微小移動が可能な状態とし、保持圧の回復によって安定した当接状態が得られる位置に微小移動を行う。   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.

この微小移動は、成形温度の165℃の雰囲気下で成形材料の粘度が急激に上昇するゲル化時間の85秒に近い吐出完了から70秒経過後まで、ロッド5が僅かに降下する射出圧力よりも高い10MPa加圧力(一次保持圧)をロッド5に付与して1〜2秒間の保持をした後、本発明の一つである、「吐出管に内在したロッド降下後の一次保持圧の解放が、ロッドを駆動させない状態で行う」に基づいて、ロッド5を上昇による外気侵入や成形品壁内が変態することのないよう、油圧のみを排除して1〜2秒間の保持を行う工程を繰り返し行った。   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.

この一次保持圧の解放時に黒鉛粒子の微小な移動を可能とした後、前記保持圧の回復によって黒鉛粉粒が相互に安定した当接状態を備えることを可能とし、この繰り返しによって安定した当接状態が確保できるものである。この結果、結合材であるフェノール樹脂がガラス転移温度(Tg)以上の加熱温度を経過する焼成過程や成形後の加熱処理などの高温雰囲気下における強度の大幅な低下を来す状態で発生する歪みの解放挙動に起因した微細な亀裂発生と、前記微細亀裂にガスが集中して生じるフクレの発生を抑制することができた。   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.

さらに、結合材であるフェノール樹脂がゲル化に伴う硬化収縮を来たし、前記フェノール樹脂に引っ張り応力を付与して内部に残留する。この残留応力は、フェノール樹脂のガラス転移温度(Tg)以上の加熱温度を経過する焼成過程や成形後の加熱処理などの高温雰囲気下で、成形品壁面に亀裂を発生させて解放する挙動を備えることになる。   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.

特に、成形材料が急激に流動方向を変化させる吐出管4直下では、常に金型よりも十分に低い温度の成形材料が集中して流入する。例えば、射出された成形材料の温度は110℃程度であって、165℃に加温した金型表面温度を低下させるうえ、最後に流入した成形材料の温度は、他の部位、例えば側壁部などにある成形材料の温度に比較して、流動中に金型からの加温されること無しに滞留することになるので、当該部位における成形材料の反応は、他の部位より遅延することになり、収縮に伴う応力が集中しやすい状態を醸し出して歪みが残留するほか、微細クラックの発生を来すこともあった。   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.

しかし、上述したロッドの降下と圧力の解放の繰り返し後の本発明の一つである、「二次保持圧の付加を製品取り出しによる金型解放時まで維持する」に基づくロッド5への35MPaの圧力保持は、成形材料の流動方向が急激に変化する吐出管4直下で成形品壁内に発生する応力を補足し、亀裂発生の抑止に寄与する。   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.

また、吐出管4を設けて、内部に備えるロッド5の降下に伴って押し出された成形材料は、射出完了降下までの時間に加温され、吐出管4直下に滞留した成形材料を排除して置き換わるので、反応の遅延を抑制して硬化収縮に伴って発生する応力の集中を抑制することができる。   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.

得られた成形品は、無酸素状態で1000℃の雰囲気下に放置してフェノール樹脂を炭化させ、カーボン凝結体の成形品を得る。このとき、焼成処理によって発生するフェノール樹脂の分解ガスが当該成形品の内部から円滑に放散するよう、フェノール樹脂の分解が活発になって急激な重量減少を来す350℃と500℃、800℃の近傍で緩い温度上昇と保持を行う。本実施の形態では、300℃迄を0.5℃/minで昇温した後に5時間保持し、さらに5℃/hr で450℃、1℃/hrで500℃に到達後に5時間の保持、750℃迄を5℃/hr、800℃迄を2℃/hrで到達後に3時間の保持、その後、0.5℃/minで1000℃に到達させて2時間の保持を行った。その後、室温まで5℃/min以下の速度で冷却し、炊飯釜の凝結体成形品を得た。   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.

このとき、フェノール樹脂の含有率が高く、粒子間に形成された空隙内を充填する成形材料を使用する場合は、焼成処理によってカーボンの残存が極めて少ないアクリルなどの有機繊維を混合して用いることが有効である。これら繊維は、フェノール樹脂に先行して熱分解が開始するので、無数の気孔を形成して、樹脂に分解起因したガスの放出が容易となる。また焼成処理時の昇温速度を促進できるので、成形品内部に分解ガスが僅かな空隙に滞留して膨張、成形品の表面を鱗片状に破壊する亀裂の形成抑止に有効であるほか、従来の昇温と保持時間を大幅に縮減することができる。具体的には、750℃迄を5℃/hr、800℃迄を2℃/hrで到達後に3時間保持、その後、0.5℃/minで1000℃に到達後に2時間保持、で行っても欠陥の発生を生じることなく、約2日間の焼成時間短縮を達成した。   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.

次に、炊飯釜としての使用には、凝結体成形品の外面には耐摩耗性と耐熱性に優れるシリコーン樹脂を、内面には調理具材の密着防止を目的にフッ素樹脂を、各々、吹付けて塗装を施した。表面に吹付けた塗料は、凝結体の粒子間で形成された空隙内を充填する含浸によるアンカー効果によって、強固な塗膜密着性が得られる。   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.

図2は実施の形態1を示す図で、炊飯釜の底面中央部における落球衝撃強度の比較結果を示す図である。本実施の形態の上述手段によって得た炊飯釜のカーボン凝結体成形品の吐出管4またはゲート1近傍である底面中央に150gの鋼球を落下して、クラックを発生することなしに耐えうる最大高さで示した衝撃強度の極端な低下の抑止効果を備えたことが、図2に示す落球衝撃強度の測定結果から確認できた。   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.

図2に示すように、落球衝撃強度の測定に供した試料は、比較例が二種類(#1、#2)、本実施の形態が四種類(#1〜#4)である。最も優れた本実施の形態の#4(焼成後にクラックの発生がなく、落球衝撃強度が50cmでも割れないもの)を基準にして、他の試料の測定結果を説明する。
(1)比較例の#1は、成形材料が本実施の形態の#4と異なるため(比較例の#1は成形材料B、本実施の形態の#4は成形材料A)、炊飯釜(カーボン凝結体成形品)に焼成後にクラックが発生するとともに、落球衝撃強度が、10cmで既に割れた。
(2)比較例の#2は、成形材料は成形材料Aであるが、吐出管4による加圧を行わないものである。そのため、炊飯釜(カーボン凝結体成形品)に焼成後にクラックが発生するとともに、落球衝撃強度が、10cmで既に割れた。
(3)本実施の形態の#1は、本実施の形態の#4と比較すると、圧力の解放と回復を行わないものである。しかし、炊飯釜(カーボン凝結体成形品)に焼成後にクラックが発生することなく、落球衝撃強度が、30cmでは割れたが、25cmでは割れなかった。比較例(#1、#2)に対して、優れていることが解る。
(4)本実施の形態の#2は、本実施の形態の#4と比較すると、圧力解放時のロッド5駆動による成形材料を金型内に追加投入する挙動が有で、上記挙動のゲル化直前迄の継続実施を行わないものである。本実施の形態の#2は、効果はあるものの、本実施の形態の中では最も特性が悪い。圧力解放時にロッド5駆動を行わないこと、上記挙動のゲル化直前迄の継続実施が効果を奏していることが解る。
(5)本実施の形態の#3は、本実施の形態の#4と比較すると、ゲル化後の加圧維持を行わないものである。落球衝撃強度が、本実施の形態の#4の50cm(割れない最大値)に対して、本実施の形態の#3は25cm(割れない最大値)であった。
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).

以上の工程を経て得た炊飯釜は、炊飯器に内蔵され、誘電加熱の適正制御を得て炊飯に供する際に係る負荷、例えば、調理道具の落下を想定した衝撃強度などに十分耐えうる耐性を保持するとともに、従来の黒鉛ブロックからの切削加工品に比較して大幅な工数短縮を達成するとともに、安定した製造と品質の確保を可能とした。   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.

なお、本実施の形態では吐出管4内に設けたゲート1構造を、本発明の一つである、「成形材料を吐出管の外周に沿った斜め上方向に成形材料を吐出する」ようにしたが、これに替えて、対向するゲート1から成形材料を上方に向けて吐出する手段を用いてもよい。しかし、対向位置から吐出した成形材料を衝突させて相互の流速を相殺して気泡の混入を抑制するように配慮することが肝要となる。   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 ゲート、3 金型キャビティ、4 吐出管、5 ロッド、6 下金型、7 上金型、8 吐出管側ランナー、9 金型側ランナー、10 成形金型、101 ゲート、103 金型キャビティ、106 下金型、106a 下金型内壁面、107 上金型、110 成形金型。   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)

内在するロッドの上死点近傍外壁の接点位置にゲートを設けた吐出管を、鍋状成形品の底面中央外壁の相当部分に配した金型を用い、カーボン粉粒とフェノール樹脂を主体として成る成形材料を注入して加熱・加圧による賦形方法であって、
射出直後に前記ロッドを降下させて加圧させた後、前記圧力を解放、さらに回復させるようにしたことを特徴とするカーボン粉粒複合樹脂の成形方法。
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.
前記吐出管に設けた前記ゲートが、成形材料を前記吐出管の外周に沿った斜め上方向に成形材料を吐出することを特徴とする請求項1に記載のカーボン粉粒複合樹脂の成形方法。   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. 前記吐出管に内在した前記ロッド降下後の一次保持圧の解放が、前記ロッドを駆動させない状態で行うことを特徴とする請求項1に記載のカーボン粉粒複合樹脂の成形方法。   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. 前記ロッドによる金型の一次保持圧での回復と解放が、成形材料のゲル化直前まで繰り返し行った後、二次保持圧の付加を製品取り出しによる金型開放時まで維持することを特徴とする請求項1乃至3のいずれかに記載のカーボン粉粒複合樹脂の成形方法。   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. 前記一次保持圧が射出圧力よりも高く、前記二次保持圧よりも十分に低い状態で前記ロッドの降下による圧縮挙動を伴う状態で行うことを特徴とする請求項4に記載のカーボン粉粒複合樹脂の成形方法。   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. 前記成形材料が、フェノール基を含む化合物とアルデヒド基を含む化合物を界面活性剤の存在下の水中で重合したフェノール樹脂未硬化物を被覆したカーボン粉粒と、成形温度で液状を成すフェノール樹脂と、の混合物を用いることを特徴とする請求項1乃至5のいずれかに記載のカーボン粉粒複合樹脂の成形方法。   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 前記界面活性剤が、高分子電解質挙動を示して重合過程のフェノール樹脂とポリイオンコンプレックスを形成したものを用いることを特徴とする請求項6に記載のカーボン粉粒複合樹脂の成形方法。   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. 前記成形材料が、フェノール樹脂より分解開始温度が低く、焼成段階でカーボン残存率が少ない有機繊維を混合して用いることを特徴とする請求項6に記載のカーボン粉粒複合樹脂の成形方法。   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.
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