JPWO2019087846A1 - Molded insulation with surface layer and its manufacturing method - Google Patents

Molded insulation with surface layer and its manufacturing method Download PDF

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JPWO2019087846A1
JPWO2019087846A1 JP2019551119A JP2019551119A JPWO2019087846A1 JP WO2019087846 A1 JPWO2019087846 A1 JP WO2019087846A1 JP 2019551119 A JP2019551119 A JP 2019551119A JP 2019551119 A JP2019551119 A JP 2019551119A JP WO2019087846 A1 JPWO2019087846 A1 JP WO2019087846A1
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carbon fiber
sheet
heat insulating
insulating material
expanded graphite
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JP7198215B2 (en
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敬一 竹内
敬一 竹内
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Osaka Gas Chemicals Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/71—Ceramic products containing macroscopic reinforcing agents
    • C04B35/78—Ceramic products containing macroscopic reinforcing agents containing non-metallic materials
    • C04B35/80—Fibres, filaments, whiskers, platelets, or the like
    • C04B35/83—Carbon fibres in a carbon matrix
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L59/00—Thermal insulation in general
    • F16L59/02—Shape or form of insulating materials, with or without coverings integral with the insulating materials

Abstract

ガスによる断熱性能の低下を抑制し得た長寿命な表面層付き成形断熱材を低コストで提供する。炭素繊維系成形断熱材と、前記炭素繊維系成形断熱材に積層された膨張黒鉛シートと、前記膨張黒鉛シートに接して積層された炭素繊維シート保護層と、を備え、前記炭素繊維シート保護層は、炭素繊維を交絡させた炭素繊維不織布シートと炭素繊維不織布シートの炭素繊維表面を被覆する炭素質からなるマトリックスと、を有する表面層付き成形断熱材。Provided at low cost a molded heat insulating material with a surface layer having a long life that can suppress the deterioration of heat insulating performance due to gas. The carbon fiber sheet protective layer includes a carbon fiber-based molded heat insulating material, an expanded graphite sheet laminated on the carbon fiber-based molded heat insulating material, and a carbon fiber sheet protective layer laminated in contact with the expanded graphite sheet. Is a molded heat insulating material with a surface layer having a carbon fiber non-woven fabric sheet in which carbon fibers are entangled and a matrix made of carbon material that coats the carbon fiber surface of the carbon fiber non-woven fabric sheet.

Description

本発明は炭素繊維を用いた成形断熱材に関し、詳しくは耐久性を高めるための表面層が設けられた成形断熱材に関する。 The present invention relates to a molded heat insulating material using carbon fibers, and more particularly to a molded heat insulating material provided with a surface layer for enhancing durability.

炭素繊維系の断熱材は、熱的安定性や断熱性能に優れ且つ軽量であることから、種々の用途で使用されている。このような断熱材には、炭素繊維を交絡してなる炭素繊維フェルトや、炭素繊維と樹脂材料の炭素化物とを含んだ炭素繊維系成形断熱材がある。炭素繊維フェルトは、可とう性に優れるという長所を有し、炭素繊維系成形断熱材は、形状安定性に優れ、微細な加工が可能であるという長所を有する。 Carbon fiber-based heat insulating materials are used in various applications because they are excellent in thermal stability and heat insulating performance and are lightweight. Such heat insulating materials include carbon fiber felt formed by entwining carbon fibers and carbon fiber-based molded heat insulating material containing carbon fibers and carbonized resin material. The carbon fiber felt has an advantage of being excellent in flexibility, and the carbon fiber-based molded heat insulating material has an advantage of being excellent in shape stability and capable of fine processing.

炭素繊維を用いた成形断熱材には、炭素繊維を交絡してなる炭素繊維フェルトに樹脂材料を含浸させ炭素化させたフェルト系の成形断熱材や、湿式法あるいは乾式法で炭素繊維ミルド（短繊維）を合成樹脂とともに成形し炭素化させたショートファイバー系の成形断熱材がある。 Molded heat insulating materials using carbon fibers include felt-based molded heat insulating materials in which carbon fiber felt made by entwining carbon fibers is impregnated with a resin material and carbonized, and carbon fiber milled (short) by a wet method or a dry method. There is a short fiber type molded heat insulating material obtained by molding (fiber) together with a synthetic resin and carbonizing it.

何れの断熱材を使用するかは、使用目的や用途に応じて適宜選択される。炭素繊維系成形断熱材は、熱的安定性、断熱性能に優れ且つ形状安定性に優れることから、シリコン、サファイア、炭化ケイ素などの結晶成長炉、金属やセラミックスの焼結に用いられる熱処理炉や熱間等方圧加圧炉（ＨＩＰ炉）、真空蒸着炉等の高温炉の断熱材として使用されている。 Which heat insulating material is used is appropriately selected according to the purpose of use and application. Since carbon fiber-based molded heat insulating materials have excellent thermal stability, heat insulating performance, and shape stability, they are used in crystal growth furnaces for silicon, sapphire, silicon carbide, etc., and heat treatment furnaces used for sintering metals and ceramics. It is used as a heat insulating material for high temperature furnaces such as hot isotropic pressure pressurizing furnaces (HIP furnaces) and vacuum deposition furnaces.

ところが、高温炉内では、酸素ガスなどの酸化性のガスが製造雰囲気に混入したりする。酸素ガスは活性（反応性）が高く、炭素繊維系成形断熱材と酸素ガスとが反応して炭素酸化物（一酸化炭素、二酸化炭素等）が生じる。これにより特に炭素繊維が劣化し、炭素繊維により構成される骨格構造が崩れ、当該骨格構造が多数の空間を形成することにより得られる断熱作用が低下する。また、この劣化により特に炭素繊維が粉化して炉内雰囲気中に放出されて、製品品質を低下させるというおそれもある。 However, in the high temperature furnace, oxidizing gas such as oxygen gas is mixed in the manufacturing atmosphere. Oxygen gas has high activity (reactivity), and carbon fiber-based molded heat insulating material reacts with oxygen gas to generate carbon oxides (carbon monoxide, carbon dioxide, etc.). As a result, the carbon fibers are particularly deteriorated, the skeletal structure composed of the carbon fibers is destroyed, and the heat insulating effect obtained by the skeletal structure forming a large number of spaces is lowered. Further, due to this deterioration, carbon fibers may be particularly pulverized and released into the atmosphere inside the furnace, which may deteriorate the product quality.

特に、炉内を常圧付近又は高圧にしたり、アルゴンガスや窒素ガスを流したりする熱処理炉やＨＩＰ炉では、気流や圧力差によって成形断熱材内部に酸化性ガスが浸透しやすく、上記問題が顕著に現れることになる。 In particular, in heat treatment furnaces and HIP furnaces in which the inside of the furnace is set to near normal pressure or high pressure, or argon gas or nitrogen gas is flowed, the oxidizing gas easily permeates into the molded heat insulating material due to the air flow or pressure difference, which causes the above problem. It will appear prominently.

この問題を解決するため、特許文献１は、膨張黒鉛を圧延して得られる膨張黒鉛シートを成形断熱材の表面に接着する技術を提案している。 In order to solve this problem, Patent Document 1 proposes a technique of adhering an expanded graphite sheet obtained by rolling expanded graphite to the surface of a molded heat insulating material.

特開２００５−１３３０３２号公報Japanese Unexamined Patent Publication No. 2005-133032.

この技術によると、実質的にガス不浸透である膨張黒鉛シートが、成形断熱材の内部へのガスの浸透を防止し、成形断熱材の劣化を防止できるとされる。 According to this technique, the expanded graphite sheet, which is substantially impermeable to gas, can prevent gas from penetrating into the molded heat insulating material and prevent deterioration of the molded heat insulating material.

本発明者が上記特許文献１の技術を検討したところ、次のような問題点があることを知った。膨張黒鉛シートは、膨張黒鉛を圧延してシート状にしているものであり、黒鉛の層と層との間を結着させるバインダー成分は存在していない。このため、膨張黒鉛シートは、反応性ガス雰囲気下で長期間使用したり、酸化損耗が起きやすい環境で使用したりすると、表面に解離などの劣化が目立つようになるとともに、黒鉛層の剥離等が進行してガス浸透防止機能を失ってしまい、成形断熱材の長寿命化を図れなくなるという課題がある。 When the present inventor examined the technique of Patent Document 1, it was found that there are the following problems. The expanded graphite sheet is made by rolling expanded graphite into a sheet, and there is no binder component that binds the graphite layers to each other. For this reason, when the expanded graphite sheet is used for a long period of time in a reactive gas atmosphere or in an environment where oxidative wear is likely to occur, deterioration such as dissociation becomes conspicuous on the surface, and the graphite layer is peeled off. However, there is a problem that the gas permeation prevention function is lost and the life of the molded heat insulating material cannot be extended.

本発明は、上記の課題を解決するためになされたものであり、断熱作用の低下や無用なコスト高を招くことなく、成形断熱材内部へのガスの浸透を長期間にわたって抑制し得た成形断熱材を提供することを目的とする。 The present invention has been made to solve the above problems, and molding can suppress the permeation of gas into the molding heat insulating material for a long period of time without incurring a decrease in heat insulating action and an unnecessary increase in cost. The purpose is to provide insulation.

上記課題を解決するための成形断熱材に係る本発明は、次のように構成されている。
炭素繊維系成形断熱材と、前記炭素繊維系成形断熱材に積層された膨張黒鉛シートと、前記膨張黒鉛シートに接して積層された炭素繊維シート保護層と、を備え、前記炭素繊維シート保護層は、炭素繊維を交絡させた炭素繊維不織布シートと炭素繊維不織布シートの炭素繊維表面を被覆する炭素質からなるマトリックスと、を有する表面層付き成形断熱材。The present invention relating to a molded heat insulating material for solving the above problems is configured as follows.
The carbon fiber sheet protective layer includes a carbon fiber-based molded heat insulating material, an expanded graphite sheet laminated on the carbon fiber-based molded heat insulating material, and a carbon fiber sheet protective layer laminated in contact with the expanded graphite sheet. Is a molded heat insulating material with a surface layer having a carbon fiber non-woven fabric sheet in which carbon fibers are entangled and a matrix made of carbon material that coats the carbon fiber surface of the carbon fiber non-woven fabric sheet.

上記本発明では、炭素繊維系成形断熱材上に、膨張黒鉛シートと、炭素繊維シート保護層と、が順に積層されている。ここで、膨張黒鉛シートは、成形断熱材内部へのガスの浸透を防止するように作用する。また、炭素繊維シート保護層は、酸化性ガスが発生した場合に、膨張黒鉛シートに先んじて酸化性ガスと反応するため、膨張黒鉛シートの早期の劣化が防止される。この結果、膨張黒鉛シートによるガス浸透防止効果を長期間にわたって得ることができる。つまり、膨張黒鉛シートおよび炭素繊維シート保護層からなる表面層は、ガスの成形断熱材内部への浸透を長期間にわたって防止するように作用する。 In the present invention, the expanded graphite sheet and the carbon fiber sheet protective layer are laminated in this order on the carbon fiber-based molded heat insulating material. Here, the expanded graphite sheet acts to prevent gas from penetrating into the molded heat insulating material. Further, since the carbon fiber sheet protective layer reacts with the oxidizing gas prior to the expanded graphite sheet when the oxidizing gas is generated, early deterioration of the expanded graphite sheet is prevented. As a result, the gas permeation prevention effect of the expanded graphite sheet can be obtained for a long period of time. That is, the surface layer composed of the expanded graphite sheet and the carbon fiber sheet protective layer acts to prevent the permeation of gas into the molded heat insulating material for a long period of time.

ここで、炭素繊維系成形断熱材は、市販のものを使用することができ、たとえば上述したフェルト系の成形断熱材や、ショートファイバー系の成形断熱材を使用できる。また、膨張黒鉛シートは、市販のものを使用することができる。また、炭素繊維不織布シートとしては、市販のものを用いることができ、たとえば炭素繊維シート、炭素繊維ペーパーや炭素繊維フェルトを用いることができる。 Here, as the carbon fiber-based molded heat insulating material, a commercially available one can be used, and for example, the felt-based molded heat insulating material described above or the short fiber-based molded heat insulating material can be used. Further, as the expanded graphite sheet, a commercially available one can be used. Further, as the carbon fiber non-woven fabric sheet, a commercially available one can be used, and for example, a carbon fiber sheet, a carbon fiber paper or a carbon fiber felt can be used.

また、炭素質からなるマトリックスは、炭素繊維表面を被覆するとともに、炭素繊維シート保護層と膨張黒鉛シートとを結着する。マトリックスは炭素質であれば特に限定はされないが、熱硬化性樹脂の炭素化物であることがより好ましい。 In addition, the matrix made of carbonaceous material covers the surface of carbon fibers and binds the carbon fiber sheet protective layer and the expanded graphite sheet. The matrix is not particularly limited as long as it is carbonaceous, but it is more preferably a carbonized product of a thermosetting resin.

また、膨張黒鉛シートは、炭素繊維系成形断熱材に接して積層されていてもよく、両者の間に接着性を高める層が介在していてもよい。膨張黒鉛シートを成形断熱材に接して積層する場合には、熱硬化性樹脂などの接着樹脂が炭素化してなる炭素化物が、両者の界面近傍に存在している構成とすることが好ましい。また、膨張黒鉛シートを２層以上積層するとコスト高になるため、膨張黒鉛シートは１層であることが好ましい。 Further, the expanded graphite sheet may be laminated in contact with the carbon fiber-based molded heat insulating material, or a layer for enhancing adhesiveness may be interposed between the two. When the expanded graphite sheet is laminated in contact with the molded heat insulating material, it is preferable that a carbonized product obtained by carbonizing an adhesive resin such as a thermosetting resin is present in the vicinity of the interface between the two. Further, it is preferable that the expanded graphite sheet has one layer because the cost increases when two or more layers of the expanded graphite sheet are laminated.

この一方、炭素繊維シート保護層は、膨張黒鉛シートに直接接している。炭素繊維シート保護層は、所望の厚みとするために２枚以上積層された構成としてもよい。 On the other hand, the carbon fiber sheet protective layer is in direct contact with the expanded graphite sheet. The carbon fiber sheet protective layer may be configured by laminating two or more sheets in order to obtain a desired thickness.

上記構成において、炭素繊維シート保護層は、かさ密度が０．１〜０．５ｇ／ｃｍ３であり、厚みが０．３〜３ｍｍであることが好ましい。In the above configuration, the carbon fiber sheet protective layer preferably has a bulk density of 0.1 to 0.5 g / cm 3 and a thickness of 0.3 to 3 mm.

炭素繊維シート保護層のかさ密度が小さくなるに伴い、膨張黒鉛シートの保護効果が小さくなる。他方、炭素繊維シート保護層のかさ密度が大きくなるに伴い、膨張黒鉛シートとの接着が難しくなる。両者のバランスから、炭素繊維シート保護層のかさ密度は、０．１〜０．５ｇ／ｃｍ３であることが好ましく、０．２〜０．４ｇ／ｃｍ３であることがより好ましく、０．２〜０．３ｇ／ｃｍ３であることがさらに好ましい。As the bulk density of the carbon fiber sheet protective layer decreases, the protective effect of the expanded graphite sheet decreases. On the other hand, as the bulk density of the carbon fiber sheet protective layer increases, it becomes difficult to adhere to the expanded graphite sheet. The balance of both, the bulk density of the carbon fiber sheet protective layer is preferably from 0.1 to 0.5 g / cm 3, more preferably 0.2~0.4g / cm 3, 0. It is more preferably 2 to 0.3 g / cm 3 .

また、炭素繊維シート保護層の厚みが小さくなるに伴い、膨張黒鉛シートの保護効果が小さくなる。他方、炭素繊維シート保護層の厚みが大きくなると、その分コスト高になる。両者のバランスから、炭素繊維シート保護層の厚みは、０．３〜３ｍｍであることが好ましく、０．４〜２．０ｍｍであることがより好ましく、０．５〜１．５ｍｍであることがさらに好ましい。 Further, as the thickness of the carbon fiber sheet protective layer becomes smaller, the protective effect of the expanded graphite sheet becomes smaller. On the other hand, as the thickness of the carbon fiber sheet protective layer increases, the cost increases accordingly. From the balance between the two, the thickness of the carbon fiber sheet protective layer is preferably 0.3 to 3 mm, more preferably 0.4 to 2.0 mm, and preferably 0.5 to 1.5 mm. More preferred.

上記構成において、炭素繊維シート保護層を構成する炭素繊維が、等方性ピッチ系炭素繊維であるであることが好ましい。 In the above configuration, the carbon fibers constituting the carbon fiber sheet protective layer are preferably isotropic pitch-based carbon fibers.

等方性ピッチ系炭素繊維は、柔らかく膨張黒鉛シートに損傷を与えにくいとともに、膨張黒鉛シートとの接着性が良好であるため、好ましい。 The isotropic pitch-based carbon fiber is preferable because it is soft and does not easily damage the expanded graphite sheet, and has good adhesion to the expanded graphite sheet.

上記課題を解決するための成形断熱材の製造方法に係る第１の本発明は、次のように構成されている。
炭素繊維不織布シートに熱硬化前の熱硬化性樹脂を含浸させる樹脂含浸炭素繊維不織布シート作製ステップと、膨張黒鉛シートが表面に取り付けられた炭素繊維系成形断熱材の前記膨張黒鉛シート表面に、前記炭素繊維不織布シートを少なくとも１つ積層して積層体となす積層ステップと、前記積層体を加圧しつつ前記熱硬化性樹脂の熱硬化温度以上に加熱して、前記炭素繊維不織布シートを前記膨張黒鉛シート表面に結着する結着ステップと、結着された前記積層体を不活性ガス雰囲気下で熱処理して、前記熱硬化性樹脂を炭素化させる炭素化ステップと、を有する表面層付き成形断熱材の製造方法。The first invention relating to the method for manufacturing a molded heat insulating material for solving the above-mentioned problems is configured as follows.
A resin-impregnated carbon fiber non-woven sheet sheet manufacturing step of impregnating a carbon fiber non-woven sheet with a thermosetting resin before thermosetting, and the expanded graphite sheet surface of the carbon fiber-based molded heat insulating material to which the expanded graphite sheet is attached to the surface, said A laminating step of laminating at least one carbon fiber non-woven sheet to form a laminated body, and heating the laminated body to a temperature higher than the thermosetting temperature of the thermosetting resin while pressurizing the laminated body to make the carbon fiber non-woven sheet into the expanded graphite. Molded insulation with a surface layer having a binding step of binding to the sheet surface and a carbonization step of heat-treating the bonded laminate in an inert gas atmosphere to carbonize the thermosetting resin. Material manufacturing method.

上記課題を解決するための成形断熱材の製造方法に係る第２の本発明は、次のように構成されている。
炭素繊維が交絡された炭素繊維構造体に熱硬化前の熱硬化性樹脂を含浸させてプリプレグとなすプリプレグ作製ステップと、炭素繊維不織布シートに熱硬化前の熱硬化性樹脂を含浸させる樹脂含浸炭素繊維不織布シート作製ステップと、前記プリプレグ上に膨張黒鉛シートを積層し、さらに前記膨張黒鉛シート表面に前記樹脂含浸炭素繊維不織布シートを少なくとも１つ積層して積層体となす積層ステップと、前記積層体を加圧しつつ前記熱硬化性樹脂の熱硬化温度以上に加熱して、前記プリプレグ、前記膨張黒鉛シート、および前記炭素繊維不織布シートを結着する結着ステップと、結着された前記積層体を不活性ガス雰囲気下で熱処理して、前記熱硬化性樹脂を炭素化させる炭素化ステップと、を有する表面層付き成形断熱材の製造方法。A second invention relating to a method for producing a molded heat insulating material for solving the above problems is configured as follows.
A prepreg production step of impregnating a carbon fiber structure in which carbon fibers are entangled with a thermosetting resin before thermosetting to form a prepreg, and a resin-impregnated carbon impregnating a carbon fiber non-woven sheet with a thermosetting resin before thermosetting. A fiber non-woven sheet manufacturing step, a laminating step of laminating an expanded graphite sheet on the prepreg, and further laminating at least one resin-impregnated carbon fiber non-woven sheet on the surface of the expanded graphite sheet to form a laminated body, and the laminated body. The binding step of binding the prepreg, the expanded graphite sheet, and the carbon fiber non-woven sheet by heating the thermosetting resin to a thermosetting temperature or higher while pressurizing the carbon fiber sheet, and the bonded laminate. A method for producing a molded heat insulating material with a surface layer, which comprises a carbonization step of carbonizing the thermosetting resin by heat treatment in an inert gas atmosphere.

上記２つの製造方法の相違点は、樹脂含浸炭素繊維不織布シートを積層する際に、成形断熱材部分がすでに炭素化しているか（第１の本発明製造方法）、炭素化していないのか（第２の本発明製造方法）という点である。これらのいずれかを採用することにより、簡便で低コストな手法で、本発明に係る表面層付き成形断熱材を製造することができる。炭素繊維が交絡された炭素繊維構造体は、フェルト系、ショートファイバー系のいずれでもよい。 The difference between the above two manufacturing methods is whether the molded heat insulating material portion is already carbonized (first manufacturing method of the present invention) or not carbonized (second) when the resin-impregnated carbon fiber non-woven fabric sheet is laminated. The present invention manufacturing method). By adopting any of these, the molded heat insulating material with a surface layer according to the present invention can be manufactured by a simple and low-cost method. The carbon fiber structure in which the carbon fibers are entangled may be either a felt type or a short fiber type.

以上に説明したように、本発明によると、低コストでもってガスの浸透を抑制し得た長寿命な表面層付き炭素繊維系成形断熱材を実現することができる。 As described above, according to the present invention, it is possible to realize a carbon fiber-based molded heat insulating material with a surface layer having a long life that can suppress the permeation of gas at low cost.

図１は、本発明に係る表面層付き成形断熱材の表面近傍の断面顕微鏡写真である。FIG. 1 is a cross-sectional micrograph of the molded heat insulating material with a surface layer according to the present invention in the vicinity of the surface.

図２は、比較例１に係る表面層付き成形断熱材の耐久性試験２後の膨張黒鉛シート表面の状態を示す顕微鏡写真である。FIG. 2 is a photomicrograph showing the state of the surface of the expanded graphite sheet after the durability test 2 of the molded heat insulating material with a surface layer according to Comparative Example 1.

（実施の形態）
本発明に係る表面層付き成形断熱材は、炭素繊維系成形断熱材と、炭素繊維系成形断熱材に積層された膨張黒鉛シートと、膨張黒鉛シートに接して積層された炭素繊維シート保護層と、を備えている。ここで、炭素繊維シート保護層は、炭素繊維を交絡させた炭素繊維不織布シートと炭素繊維不織布シートの炭素繊維表面を被覆する炭素質からなるマトリックスと、を有している。つまり、本発明に係る表面層付き成形断熱材は、炭素繊維系成形断熱材の上に、膨張黒鉛シートと炭素繊維シート保護層とからなる表面層が設けられている構成であり、このうちの炭素繊維シート保護層が最表層となる。(Embodiment)
The molded heat insulating material with a surface layer according to the present invention includes a carbon fiber-based molded heat insulating material, an expanded graphite sheet laminated on the carbon fiber-based molded heat insulating material, and a carbon fiber sheet protective layer laminated in contact with the expanded graphite sheet. , Is equipped. Here, the carbon fiber sheet protective layer has a carbon fiber non-woven fabric sheet in which carbon fibers are entangled and a matrix made of carbonaceous material that coats the carbon fiber surface of the carbon fiber non-woven fabric sheet. That is, the molded heat insulating material with a surface layer according to the present invention has a configuration in which a surface layer composed of an expanded graphite sheet and a carbon fiber sheet protective layer is provided on the carbon fiber-based molded heat insulating material. The carbon fiber sheet protective layer is the outermost layer.

上記構成では、膨張黒鉛シートが成形断熱材内部へのガスの浸透を防止するように作用する。また、炭素繊維シート保護層は、酸化性ガスが発生した場合に、膨張黒鉛シートに先んじて酸化性ガスと反応するため、膨張黒鉛シートの早期の損耗が防止される。この結果、膨張黒鉛シートによるガス浸透防止効果を長期間にわたって得ることができる。すなわち、膨張黒鉛シートと炭素繊維シート保護層との二層構造の表面層は、ガスの成形断熱材内部への浸透を長期間にわたって防止するように作用する。 In the above configuration, the expanded graphite sheet acts to prevent gas from penetrating into the molded heat insulating material. Further, since the carbon fiber sheet protective layer reacts with the oxidizing gas prior to the expanded graphite sheet when the oxidizing gas is generated, early wear of the expanded graphite sheet is prevented. As a result, the gas permeation prevention effect of the expanded graphite sheet can be obtained for a long period of time. That is, the surface layer having a two-layer structure of the expanded graphite sheet and the carbon fiber sheet protective layer acts to prevent the permeation of gas into the molded heat insulating material for a long period of time.

ここで、炭素繊維系成形断熱材と膨張黒鉛シートとの間に、両者の接着性を高める層（接着層）が設けられていてもよい。この層は、たとえば、熱硬化性樹脂が含浸された炭素繊維不織布シートを炭素化してなるものとすることができる。接着層なしでも両者を強固に接着できる場合には、接着層は設けなくてもよい。 Here, a layer (adhesive layer) for enhancing the adhesiveness between the carbon fiber-based molded heat insulating material and the expanded graphite sheet may be provided. This layer can be made by carbonizing, for example, a carbon fiber non-woven fabric sheet impregnated with a thermosetting resin. If the two can be firmly adhered without the adhesive layer, the adhesive layer may not be provided.

ここで、炭素繊維系成形断熱材、接着層、炭素繊維シート保護層などを構成する炭素繊維としては、特に限定されることはなく、例えば石炭又は石油由来の異方性又は等方性ピッチ系、ポリアクリロニトリル（ＰＡＮ）系、レーヨン系、フェノール系、セルロース系等の炭素繊維を、単一種又は複数種混合して用いることができる。中でも、等方性ピッチ系炭素繊維が、柔らかく黒鉛シートに損傷を与えにくく、黒鉛シートとの接着性が良好であるため、好ましい。 Here, the carbon fibers constituting the carbon fiber-based molded heat insulating material, the adhesive layer, the carbon fiber sheet protective layer and the like are not particularly limited, and for example, an anisotropic or isotropic pitch system derived from coal or petroleum. , Polyacrylonitrile (PAN) -based, rayon-based, phenol-based, cellulose-based and other carbon fibers can be used alone or in admixture of a plurality of types. Of these, isotropic pitch-based carbon fibers are preferable because they are soft and do not easily damage the graphite sheet, and have good adhesion to the graphite sheet.

いずれの炭素繊維も、その微視的な構造としては特に限定されず、形状（巻縮型、直線型、直径、長さ等）が同一のもののみを用いてもよく、また異なる構造のものが混合されていてもよい。ただし、炭素繊維の種類やその微視的構造は、製造される表面層付き成形断熱材の物性に影響を与えるので、用途に応じて適宜選択するのがよい。 The microscopic structure of any of the carbon fibers is not particularly limited, and only those having the same shape (curvature type, linear type, diameter, length, etc.) may be used, or carbon fibers having different structures may be used. May be mixed. However, since the type of carbon fiber and its microscopic structure affect the physical properties of the molded heat insulating material with a surface layer to be produced, it is preferable to appropriately select it according to the application.

炭素繊維系成形断熱材としては、特に限定されることはなく、市販のものを適宜使用できる。例えば、厚みが３〜１５ｍｍ程度の炭素繊維シートが複数積層されたものを用いることができる。また、長さや幅は特に限定されることはない。また、炭素繊維の微視的構造としては、ランダムな方向に配向した炭素繊維が複雑に交わっているものを用いることが好ましい。 The carbon fiber-based molded heat insulating material is not particularly limited, and a commercially available material can be appropriately used. For example, a carbon fiber sheet having a thickness of about 3 to 15 mm in which a plurality of carbon fiber sheets are laminated can be used. Moreover, the length and width are not particularly limited. Further, as the microscopic structure of the carbon fibers, it is preferable to use one in which carbon fibers oriented in random directions are intricately intersected.

膨張黒鉛シートとしては、特に限定されることはなく、市販のものを適宜使用できる。 The expanded graphite sheet is not particularly limited, and a commercially available one can be appropriately used.

炭素繊維シート保護層を構成する炭素繊維不織布シートとしては、特に限定されることはなく、例えば厚みが０．３〜３ｍｍ程度のものを用いることができる。また、長さや幅は特に限定されることはない。また、炭素繊維不織布シートの微視的構造としては、最次元的に、あるいは面方向にランダムな方向に配向した炭素繊維が複雑に交わっているものを用いることが好ましい。 The carbon fiber non-woven fabric sheet constituting the carbon fiber sheet protective layer is not particularly limited, and for example, a carbon fiber non-woven fabric sheet having a thickness of about 0.3 to 3 mm can be used. Moreover, the length and width are not particularly limited. Further, as the microscopic structure of the carbon fiber non-woven fabric sheet, it is preferable to use one in which carbon fibers oriented in the most dimensional or random directions in the plane direction are intricately intersected.

また、これらの材料は、長尺や長幅なものを用いて表面層付き成形断熱材を作製後に切断等してもよく、表面層付き成形断熱材のサイズにあらかじめ切断してもよい。 Further, these materials may be cut or the like after producing the molded heat insulating material with a surface layer using a long or long material, or may be cut in advance to the size of the molded heat insulating material with a surface layer.

マトリックスは、炭素繊維の表面全部、あるいは、炭素繊維の表面の一部を被覆し、あるいは炭素繊維相互間を埋めるように存在しているものである。また、炭素マトリックスは炭素質であればよく、その由来となる化合物は特に限定されることはない。なかでも、炭素繊維不織布シートに含浸可能な樹脂材料の炭素化物であることが好ましい。炭素繊維系成形断熱材と膨張黒鉛シートとの間に接着層を設ける場合には、接着層、炭素繊維不織布シートに含浸させる熱硬化性樹脂が同一の材料であることが好ましい。このような樹脂材料としては、フェノール樹脂、フラン樹脂、ポリイミド樹脂、エポキシ樹脂等の熱硬化性樹脂が好ましい。熱硬化性樹脂を用いると、膨張黒鉛シートと炭素繊維不織布シートとを熱硬化により簡便かつ強固に結着させることができる。 The matrix is present so as to cover the entire surface of the carbon fibers or a part of the surface of the carbon fibers, or fill the spaces between the carbon fibers. Further, the carbon matrix may be carbonaceous, and the compound from which it is derived is not particularly limited. Of these, a carbonized resin material that can be impregnated into the carbon fiber non-woven fabric sheet is preferable. When an adhesive layer is provided between the carbon fiber-based molded heat insulating material and the expanded graphite sheet, it is preferable that the adhesive layer and the thermosetting resin impregnated in the carbon fiber non-woven fabric sheet are the same material. As such a resin material, a thermosetting resin such as a phenol resin, a furan resin, a polyimide resin, or an epoxy resin is preferable. When a thermosetting resin is used, the expanded graphite sheet and the carbon fiber non-woven fabric sheet can be easily and firmly bonded by thermosetting.

ここで、熱硬化性樹脂は１種のみを用いてもよく、２種以上を混合して用いてもよい。また、熱硬化性樹脂は、そのまま炭素繊維不織布シートに含ませてもよく、溶剤で希釈して含ませてもよい。溶剤としては、メチルアルコール、エチルアルコール等のアルコールを用いることができる。 Here, only one type of thermosetting resin may be used, or two or more types may be mixed and used. Further, the thermosetting resin may be contained in the carbon fiber non-woven fabric sheet as it is, or may be diluted with a solvent and contained. As the solvent, alcohols such as methyl alcohol and ethyl alcohol can be used.

また、成形断熱材のかさ密度は、０．１０〜０．３０ｇ／ｃｍ３とすることが好ましく、０．１２〜０．２０ｇ／ｃｍ３であることがより好ましく、０．１３〜０．１６ｇ／ｃｍ３であることがさらに好ましい。成形断熱材の厚みは、目的とする断熱性能などに応じて適宜設定すればよい。The bulk density of the molded heat insulating material is preferably in a 0.10~0.30g / cm 3, more preferably 0.12~0.20g / cm 3, 0.13~0.16g further preferably / cm 3. The thickness of the molded heat insulating material may be appropriately set according to the desired heat insulating performance and the like.

また、膨張黒鉛シートのかさ密度は、０．５〜１．５ｇ／ｃｍ３とすることが好ましく、０．６〜１．３ｇ／ｃｍ３であることがより好ましく、０．８〜１．１ｇ／ｃｍ３であることがさらに好ましい。また、膨張黒鉛シートの厚みは、０．１〜１．５ｍｍであることが好ましく、０．２〜１．０ｍｍであることがより好ましく、０．３〜０．５ｍｍであることがさらに好ましい。The bulk density of the expanded graphite sheet is preferably set to 0.5 to 1.5 g / cm 3, more preferably 0.6~1.3g / cm 3, 0.8~1.1g further preferably / cm 3. The thickness of the expanded graphite sheet is preferably 0.1 to 1.5 mm, more preferably 0.2 to 1.0 mm, and even more preferably 0.3 to 0.5 mm.

次に、成形断熱材の製造方法について説明する。 Next, a method for manufacturing the molded heat insulating material will be described.

（第１の製造方法）
（膨張黒鉛シートが貼りつけられた成形断熱材の準備）
市販の黒鉛シートが接着された成形断熱材を使用することができる。また、熱硬化性樹脂などを用いて、成形断熱材に膨張黒鉛シートを貼りつけ、その後熱硬化、炭素化を行って両者を接着してもよい。このとき、成形断熱材と膨張黒鉛シートとの間に、熱硬化性樹脂を含浸させた炭素繊維ペーパーなどを介在させたり、熱硬化性樹脂などの接着剤液を膨張黒鉛シート表面および／または成形断熱材表面に塗布したりして、両者の密着性を高める構成としてもよい。熱硬化や炭素化は、公知の手法を採用できる。熱硬化性樹脂は、そのまま用いてもよく、メタノール、エタノールなどのアルコール溶媒に溶解させて用いてもよく、炭素質の粒子や短繊維がさらに含まれている構成としてもよい。(First manufacturing method)
(Preparation of molded heat insulating material to which expanded graphite sheet is attached)
A molded heat insulating material to which a commercially available graphite sheet is adhered can be used. Further, the expanded graphite sheet may be attached to the molded heat insulating material using a thermosetting resin or the like, and then thermosetting and carbonization may be performed to bond the two. At this time, a carbon fiber paper impregnated with a thermosetting resin or the like is interposed between the molded heat insulating material and the expanded graphite sheet, or an adhesive liquid such as a thermosetting resin is applied to the surface of the expanded graphite sheet and / or molding. It may be applied to the surface of the heat insulating material to improve the adhesion between the two. Known methods can be adopted for thermosetting and carbonization. The thermosetting resin may be used as it is, may be used by dissolving it in an alcohol solvent such as methanol or ethanol, or may be configured to further contain carbonaceous particles and short fibers.

ここで、成形断熱材の形状は特に限定されるものではなく、たとえば直方体や円筒状などであればよい。 Here, the shape of the molded heat insulating material is not particularly limited, and may be, for example, a rectangular parallelepiped or a cylindrical shape.

（樹脂含浸炭素繊維不織布シート作製ステップ）
炭素繊維不織布シートは、市販のものを用いることができる。炭素繊維不織布シートに、熱硬化性樹脂溶液を塗布やスプレーにより含浸させて、樹脂含浸炭素繊維不織布シートとなす。(Resin-impregnated carbon fiber non-woven fabric sheet manufacturing step)
As the carbon fiber non-woven fabric sheet, a commercially available one can be used. The carbon fiber non-woven fabric sheet is impregnated with a thermosetting resin solution by coating or spraying to form a resin-impregnated carbon fiber non-woven fabric sheet.

（積層ステップ）
膨張黒鉛シートが接着された成形断熱材の膨張黒鉛シート上に接して、樹脂含浸炭素繊維不織布シートを積層して積層体となす。樹脂含浸炭素繊維不織布シートは、２枚以上積層してもよい。(Laminating step)
The expanded graphite sheet is in contact with the expanded graphite sheet of the molded heat insulating material to which the expanded graphite sheet is adhered, and the resin-impregnated carbon fiber non-woven fabric sheet is laminated to form a laminate. Two or more resin-impregnated carbon fiber non-woven fabric sheets may be laminated.

（結着ステップ）
上記積層体を目的の厚みとなるようにプレス機を用いて加圧しつつ、熱硬化性樹脂の硬化温度以上の温度に加熱し、所定の時間（例えば、１〜１０時間）保持して、積層体を結着する。(Binding step)
While pressurizing the laminate to the desired thickness using a press machine, the laminate is heated to a temperature equal to or higher than the curing temperature of the thermosetting resin, held for a predetermined time (for example, 1 to 10 hours), and then laminated. Tie the body together.

（炭素化ステップ）
結着された積層体を、不活性雰囲気で１０００〜２５００℃で所定の時間（例えば、１〜２０時間）加熱し、熱硬化性樹脂を炭素化させて、表面層付きの成形断熱材を得る。この炭素化によって、膨張黒鉛シート上に積層された樹脂含浸炭素繊維不織布シートは、炭素繊維シート保護層となる。また、膨張黒鉛シートと成形断熱材との間に樹脂含浸炭素繊維不織布シートを配置した場合、この層は炭素化によって接着層となる。(Carbonization step)
The bonded laminate is heated in an inert atmosphere at 1000 to 2500 ° C. for a predetermined time (for example, 1 to 20 hours) to carbonize the thermosetting resin to obtain a molded heat insulating material with a surface layer. .. By this carbonization, the resin-impregnated carbon fiber non-woven fabric sheet laminated on the expanded graphite sheet becomes a carbon fiber sheet protective layer. Further, when a resin-impregnated carbon fiber non-woven fabric sheet is arranged between the expanded graphite sheet and the molded heat insulating material, this layer becomes an adhesive layer by carbonization.

（第２の製造方法）
第２の製造方法では、成形断熱材として炭素化されていないものを用いる点で上記第１の製造方法と異なっている。ここで、樹脂含浸炭素繊維不織布シート作製ステップ、結着ステップ、炭素化ステップは、上記第１の製造方法と同様であるため、これらについての詳細な説明は省略する。(Second manufacturing method)
The second manufacturing method is different from the first manufacturing method in that a non-carbonized material is used as the molded heat insulating material. Here, since the resin-impregnated carbon fiber non-woven fabric sheet manufacturing step, the binding step, and the carbonization step are the same as those in the first manufacturing method, detailed description thereof will be omitted.

（プリプレグ作製ステップ）
炭素繊維が交絡された炭素繊維構造体に熱硬化前の熱硬化性樹脂を含浸させてプリプレグとなす。炭素繊維構造体としては、フェルト系のものやショートファイバー系のものを用いることができる。好ましくは炭素繊維が三次元的にランダムに交絡されたものを用いる。熱硬化性樹脂は、炭素繊維不織布シートに含浸させるものと同様でよく、溶媒に溶解した状態で含浸させてもよい。(Prepreg production step)
A carbon fiber structure in which carbon fibers are entangled is impregnated with a thermosetting resin before thermosetting to form a prepreg. As the carbon fiber structure, a felt type structure or a short fiber type structure can be used. Preferably, carbon fibers are randomly entangled three-dimensionally. The thermosetting resin may be the same as that impregnated in the carbon fiber non-woven fabric sheet, and may be impregnated in a state of being dissolved in a solvent.

（樹脂含浸炭素繊維不織布シート作製ステップ）
上記第１の製造方法と同様にして、炭素繊維不織布シートに熱硬化前の熱硬化性樹脂を含浸させて樹脂含浸炭素繊維不織布シート作製する。(Resin-impregnated carbon fiber non-woven fabric sheet manufacturing step)
A resin-impregnated non-woven fabric sheet is produced by impregnating a carbon fiber non-woven fabric sheet with a thermosetting resin before thermosetting in the same manner as in the first manufacturing method.

（積層ステップ）
プリプレグ上に膨張黒鉛シートを積層し、さらに膨張黒鉛シート表面に樹脂含浸炭素繊維不織布シートを少なくとも１つ積層して積層体となす。このとき、所望とする断熱性能を得るために、プリプレグを２以上積層する構成としてもよい。(Laminating step)
An expanded graphite sheet is laminated on the prepreg, and at least one resin-impregnated carbon fiber non-woven fabric sheet is further laminated on the surface of the expanded graphite sheet to form a laminate. At this time, in order to obtain the desired heat insulating performance, two or more prepregs may be laminated.

また、上記第１の製造方法と同様に、熱硬化性樹脂を含浸させた炭素繊維ペーパーを、プリプレグと膨張黒鉛シートとの間に介在させたり、熱硬化性樹脂などの接着剤液を膨張黒鉛シート表面および／または成形断熱材表面に塗布したりしてもよい。また、結着ステップで加圧している際に、十分な量の熱硬化性樹脂が膨張黒鉛シートとの界面に存在する場合には、このような手段を講じなくともよい。さらに、熱硬化性樹脂を含浸させた炭素繊維ペーパーとしては、上記樹脂含浸炭素繊維不織布シートと同一のものを用いることもできる。 Further, as in the first manufacturing method, a carbon fiber paper impregnated with a thermosetting resin is interposed between the prepreg and the expanded graphite sheet, or an adhesive liquid such as a thermosetting resin is applied to the expanded graphite. It may be applied to the surface of the sheet and / or the surface of the molded heat insulating material. Further, when a sufficient amount of thermosetting resin is present at the interface with the expanded graphite sheet during pressurization in the binding step, it is not necessary to take such measures. Further, as the carbon fiber paper impregnated with the thermosetting resin, the same material as the resin-impregnated carbon fiber non-woven fabric sheet can also be used.

この後、上記第１の製造方法と同様にして、結着ステップおよび炭素化ステップを行う。この炭素化によって、プリプレグは炭素繊維系成形断熱材となり、樹脂含浸炭素繊維不織布シートは炭素繊維シート保護層となる。 After that, the binding step and the carbonization step are carried out in the same manner as in the first manufacturing method. By this carbonization, the prepreg becomes a carbon fiber-based molded heat insulating material, and the resin-impregnated carbon fiber non-woven fabric sheet becomes a carbon fiber sheet protective layer.

ここで、特に２０００℃以上の温度で熱処理する場合、炭素繊維やマトリックスなどの黒鉛構造が発展する場合もあるが、本発明においては、全ての炭素質材料は、非晶質炭素からなる構造、黒鉛質炭素からなる構造、両者が混在した構造全てを含むものを意味する。 Here, especially when heat-treated at a temperature of 2000 ° C. or higher, a graphite structure such as carbon fibers or a matrix may develop, but in the present invention, all carbonaceous materials have a structure composed of amorphous carbon. It means a structure made of graphitic carbon and a structure in which both are mixed.

実施例に基づいて、本発明をさらに詳細に説明する。 The present invention will be described in more detail based on examples.

（実施例１）
成形断熱材（表面層が設けられていないもの）としては、市販のピッチ系炭素繊維からなるフェルト系成形断熱材（大阪ガスケミカル製ＤＯＮ−１０００−Ｒ 形状：厚み３０ｍｍ、幅１ｍ、長さ１．５ｍの平板、かさ密度：０．１３ｇ／ｃｍ３）を用いた。(Example 1)
As the molded heat insulating material (those without a surface layer), a felt-based molded heat insulating material made of commercially available pitch-based carbon fiber (DON-1000-R manufactured by Osaka Gas Chemical Co., Ltd. Shape: thickness 30 mm, width 1 m, length 1) A .5 m flat plate, bulk density: 0.13 g / cm 3 ) was used.

市販のピッチ系炭素繊維からなるカーボンペーパー（大阪ガスケミカル製ドナカーボペーパー Ｓ−２５５ＡＨ 厚み２．４ｍｍ、幅１ｍ、長さ１．５ｍ、目付：７５ｇ／ｍ2）３０重量部に、レゾール系フェノール樹脂７０重量部を均一含浸させ熱硬化性樹脂が含浸された炭素繊維不織布シートを作製した。Commercially available carbon paper made of pitch-based carbon fiber (Donna Carbo Paper S-255AH manufactured by Osaka Gas Chemical Co., Ltd., thickness 2.4 mm, width 1 m, length 1.5 m, grain: 75 g / m 2 ) 30 parts by weight of resin-based phenol A carbon fiber non-woven fabric sheet impregnated with a thermosetting resin was produced by uniformly impregnating 70 parts by weight of the resin.

上記成形断熱材に、上記熱硬化性樹脂含浸炭素繊維不織布シートを乗せ、その上に同じ幅及び長さの膨張黒鉛シート(東洋炭素製 パーマフォイルＰＦ−３８ 形状：厚み０．３８ｍｍ)を乗せ、さらに膨張黒鉛シートの上に上記熱硬化性樹脂含浸炭素繊維不織布シートを１枚乗せて、積層体となした。この後、当該積層体を、加熱圧縮プレスを用いて、面圧０．０５ＭＰａ、加熱温度２００℃で３０分間保持し、熱硬化性樹脂を熱硬化させて、当該積層体を接着した。 The thermosetting resin-impregnated carbon fiber non-woven fabric sheet is placed on the molded heat insulating material, and an expanded graphite sheet (Toyo Tanso Permafoil PF-38 shape: thickness 0.38 mm) having the same width and length is placed on the molded heat insulating material. Further, one sheet of the above-mentioned thermosetting resin-impregnated carbon fiber non-woven fabric sheet was placed on the expanded graphite sheet to form a laminated body. After that, the laminate was held for 30 minutes at a surface pressure of 0.05 MPa and a heating temperature of 200 ° C. using a heat compression press, and the thermosetting resin was thermally cured to bond the laminate.

熱硬化後の積層体を熱処理炉に入れ、不活性雰囲気下、２０００℃で５時間保持する熱処理を行って、熱硬化性樹脂を炭素化し、膨張黒鉛シートと炭素繊維シート保護層とからなる表面層が設けられた成形断熱材を得た。このとき、炭素繊維シート保護層のかさ密度が０．２４ｇ／ｃｍ３であり、厚みが０．６ｍｍであった。The heat-cured laminate is placed in a heat treatment furnace and heat-treated at 2000 ° C. for 5 hours in an inert atmosphere to carbonize the thermosetting resin, and a surface composed of an expanded graphite sheet and a carbon fiber sheet protective layer. A molded heat insulating material provided with a layer was obtained. At this time, the bulk density of the carbon fiber sheet protective layer was 0.24 g / cm 3 , and the thickness was 0.6 mm.

（比較例１）
膨張黒鉛シート上に熱硬化性樹脂含浸炭素繊維不織布シートを積層しなかったこと以外は、実施例１と同様な方法で黒鉛シートが接着された成形断熱材を得た。(Comparative Example 1)
A molded heat insulating material to which the graphite sheet was adhered was obtained by the same method as in Example 1 except that the thermosetting resin-impregnated carbon fiber non-woven fabric sheet was not laminated on the expanded graphite sheet.

上記実施例１及び比較例１に係る表面層付き成形断熱材について、以下の条件で耐久性、剥離性を測定した。 The durability and peelability of the molded heat insulating material with a surface layer according to Example 1 and Comparative Example 1 were measured under the following conditions.

（耐久性試験１）
上記実施例１及び比較例１に係る表面層付き成形断熱材を、５０ｍｍ×５０ｍｍ×３０ｍｍの直方体に切り出し、温度７００℃、空気流量２Ｌ／ｍｉｎに設定された空気雰囲気の電気炉に保持し、表面層の剥離状態を観察した。この結果、実施例１にかかる成形断熱材は試験開始から３時間後に表面層の消耗が見られたものの、この時点で膨張黒鉛シートには剥離は見られなかった。他方、比較例１にかかる成形断熱材は、試験開始から３時間後に膨張黒鉛シートの剥離が見られた。(Durability test 1)
The molded heat insulating material with a surface layer according to Example 1 and Comparative Example 1 was cut into a rectangular parallelepiped of 50 mm × 50 mm × 30 mm and held in an electric furnace having an air atmosphere set at a temperature of 700 ° C. and an air flow rate of 2 L / min. The peeled state of the surface layer was observed. As a result, although the surface layer of the molded heat insulating material according to Example 1 was consumed 3 hours after the start of the test, no peeling was observed on the expanded graphite sheet at this time. On the other hand, in the molded heat insulating material according to Comparative Example 1, peeling of the expanded graphite sheet was observed 3 hours after the start of the test.

（耐久性試験２）
上記実施例１及び比較例１に係る表面層付き成形断熱材を、５０ｍｍ×５０ｍｍ×３０ｍｍの直方体に切り出し、温度７００℃、空気流量２Ｌ／ｍｉｎに設定された空気雰囲気の電気炉に４時間保持した。試験後の断熱材の表面を走査型電子顕微鏡で観察したところ、実施例１では、炭素繊維保護層の劣化は見られたものの膨張黒鉛シートの劣化が殆ど確認されなかった。図２は、比較例１に係る表面層付き成形断熱材の耐久性試験２後の膨張黒鉛シート表面の状態を示す顕微鏡写真である。比較例１では、図２に示すように、膨張黒鉛シートに解離などの劣化が見られた。(Durability test 2)
The molded heat insulating material with a surface layer according to Example 1 and Comparative Example 1 was cut into a rectangular parallelepiped of 50 mm × 50 mm × 30 mm and held in an electric furnace having an air atmosphere set at a temperature of 700 ° C. and an air flow rate of 2 L / min for 4 hours. did. When the surface of the heat insulating material after the test was observed with a scanning electron microscope, in Example 1, deterioration of the carbon fiber protective layer was observed, but deterioration of the expanded graphite sheet was hardly confirmed. FIG. 2 is a photomicrograph showing the state of the surface of the expanded graphite sheet after the durability test 2 of the molded heat insulating material with a surface layer according to Comparative Example 1. In Comparative Example 1, as shown in FIG. 2, deterioration such as dissociation was observed in the expanded graphite sheet.

（耐久性試験３）
上記実施例１及び比較例１に係る表面層付き成形断熱材を、５０ｍｍ×５０ｍｍ×３０ｍｍの直方体に切り出し、温度７００℃、空気流量２Ｌ／ｍｉｎに設定された空気雰囲気の電気炉に保持した。このとき、表面層の剥離状態を観察するとともに、酸化消耗による表面層付き成形断熱材の質量変化を測定した。この際、表面層のみ空気が触れるように治具にて表面層以外（膨張黒鉛シートと炭素繊維シート保護層以外）を保護した。この結果、実施例１にかかる成形断熱材は、試験開始から６時間後の消耗率（表面層付きの成形断熱材の質量減少率）が１８．８％であり、この時点で膨張黒鉛シートの剥離は見られなかった。他方、比較例１にかかる成形断熱材は、試験開始から６時間後の消耗率が２６．３％であり、この時点で膨張黒鉛シートの剥離が見られた。(Durability test 3)
The molded heat insulating material with a surface layer according to Example 1 and Comparative Example 1 was cut into a rectangular parallelepiped of 50 mm × 50 mm × 30 mm and held in an electric furnace having an air atmosphere set at a temperature of 700 ° C. and an air flow rate of 2 L / min. At this time, the peeled state of the surface layer was observed, and the mass change of the molded heat insulating material with the surface layer due to oxidative consumption was measured. At this time, other than the surface layer (other than the expanded graphite sheet and the carbon fiber sheet protective layer) was protected with a jig so that only the surface layer was exposed to air. As a result, the molded heat insulating material according to Example 1 had a consumption rate (mass reduction rate of the molded heat insulating material with a surface layer) of 18.8% 6 hours after the start of the test, and at this point, the expanded graphite sheet had a consumption rate of 18.8%. No peeling was seen. On the other hand, the molded heat insulating material according to Comparative Example 1 had a consumption rate of 26.3% 6 hours after the start of the test, and at this point, peeling of the expanded graphite sheet was observed.

（剥離試験）
上記実施例１にかかる成形断熱材を４ｃｍ×４ｃｍ×３ｃｍの直方体に切り出し、試験片とした。２液性接着剤を用いて、この試験片の積層方向（厚さ方向）上下面に剥離試験治具を接着し、エー・アンド・デイ製テンシロン万能材料試験機（ＲＴＣ−１２１０）を用いて、クロスヘッドスピード１ｍｍ／ｍｉｎで厚さ方向に引っ張った。この結果、成形断熱材部分の破壊が膨張黒鉛シートや炭素繊維シート保護層の破壊や剥離よりも先に起こった。このことから、炭素繊維シート保護層と黒鉛シートとの接着強度は成形断熱材部分よりも高く、十分なものであることが確認された。(Peeling test)
The molded heat insulating material according to Example 1 was cut into a rectangular parallelepiped of 4 cm × 4 cm × 3 cm and used as a test piece. Using a two-component adhesive, attach a peeling test jig to the upper and lower surfaces of the test pieces in the stacking direction (thickness direction), and use an A & D Tencilon universal material tester (RTC-1210). , Pulled in the thickness direction at a cross head speed of 1 mm / min. As a result, the fracture of the molded heat insulating material portion occurred before the fracture or peeling of the expanded graphite sheet or the carbon fiber sheet protective layer. From this, it was confirmed that the adhesive strength between the carbon fiber sheet protective layer and the graphite sheet was higher than that of the molded heat insulating material portion, which was sufficient.

以上のことから、本発明によると、膨張黒鉛シートおよび炭素繊維シート保護層の２層構造の表面層を設けるという簡便な手法で、成形断熱材のガスによる劣化を長期間に抑制し得た表面層付き成形断熱材を実現できることが分かる。 From the above, according to the present invention, a surface that can suppress deterioration of the molded heat insulating material due to gas for a long period of time by a simple method of providing a surface layer having a two-layer structure of an expanded graphite sheet and a carbon fiber sheet protective layer. It can be seen that a layered molded heat insulating material can be realized.

図１に、実施例１に係る表面層付き成形断熱材の表面層近傍の断面顕微鏡写真を示す。この写真からわかるように、炭素繊維間の空隙が多い成形断熱材４上に、炭素繊維間の空隙が成形断熱材４よりも少ない接着シート３、緻密な構造の膨張黒鉛シート２、接着シート３とほぼ同様の炭素繊維シート保護層１、が順に積層されていることが分かる。 FIG. 1 shows a cross-sectional micrograph of the molded heat insulating material with a surface layer according to Example 1 in the vicinity of the surface layer. As can be seen from this photograph, on the molded heat insulating material 4 having many voids between carbon fibers, an adhesive sheet 3 having fewer gaps between carbon fibers than the molded heat insulating material 4, an expanded graphite sheet 2 having a dense structure, and an adhesive sheet 3 It can be seen that the carbon fiber sheet protective layers 1 and the like are laminated in this order.

なお、上記実施例では、本発明にかかる第１の製造方法を採用したが、第２の製造方法を採用しても同様の効果が得られる。 In the above embodiment, the first manufacturing method according to the present invention is adopted, but the same effect can be obtained by adopting the second manufacturing method.

上記で説明したように、本発明によると、大幅なコスト上昇を伴うことなく、ガスによる断熱性能の低下を抑制し得た長寿命な表面層付き成形断熱材を実現できるので、その産業上の利用可能性は大きい。 As described above, according to the present invention, it is possible to realize a long-life molded heat insulating material with a surface layer that can suppress a deterioration in heat insulating performance due to gas without significantly increasing the cost. Great availability.

１ 炭素繊維シート保護層
２ 膨張黒鉛シート
３ 接着シート
４ 成形断熱材1 Carbon fiber sheet protective layer 2 Expanded graphite sheet 3 Adhesive sheet 4 Molded heat insulating material

Claims (5)

炭素繊維系成形断熱材と、
前記炭素繊維系成形断熱材に積層された膨張黒鉛シートと、
前記膨張黒鉛シートに接して積層された炭素繊維シート保護層と、を備え、
前記炭素繊維シート保護層は、炭素繊維を交絡させた炭素繊維不織布シートと炭素繊維不織布シートの炭素繊維表面を被覆する炭素質からなるマトリックスと、を有する、
表面層付き成形断熱材。Carbon fiber molded insulation and
The expanded graphite sheet laminated on the carbon fiber-based molded heat insulating material and
A carbon fiber sheet protective layer laminated in contact with the expanded graphite sheet is provided.
The carbon fiber sheet protective layer has a carbon fiber non-woven fabric sheet in which carbon fibers are entangled and a matrix made of carbonaceous material that covers the carbon fiber surface of the carbon fiber non-woven fabric sheet.
Molded insulation with surface layer. 前記炭素繊維シート保護層は、かさ密度が０．１〜０．５ｇ／ｃｍ３であり、厚みが０．３〜３ｍｍである、
ことを特徴とする請求項１に記載の表面層付き成形断熱材。The carbon fiber sheet protective layer has a bulk density of 0.1 to 0.5 g / cm 3 and a thickness of 0.3 to 3 mm.
The molded heat insulating material with a surface layer according to claim 1. 前記炭素繊維シート保護層を構成する炭素繊維が、等方性ピッチ系炭素繊維である、
ことを特徴とする請求項１又は２に記載の表面層付き成形断熱材。The carbon fibers constituting the carbon fiber sheet protective layer are isotropic pitch carbon fibers.
The molded heat insulating material with a surface layer according to claim 1 or 2. 炭素繊維不織布シートに熱硬化前の熱硬化性樹脂を含浸させる樹脂含浸炭素繊維不織布シート作製ステップと、
膨張黒鉛シートが表面に取り付けられた炭素繊維系成形断熱材の前記膨張黒鉛シート表面に、前記炭素繊維不織布シートを少なくとも１つ積層して積層体となす積層ステップと、
前記積層体を加圧しつつ前記熱硬化性樹脂の熱硬化温度以上に加熱して、前記炭素繊維不織布シートを前記膨張黒鉛シート表面に結着する結着ステップと、
結着された前記積層体を不活性ガス雰囲気下で熱処理して、前記熱硬化性樹脂を炭素化させる炭素化ステップと、
を有する表面層付き成形断熱材の製造方法。A resin-impregnated non-woven fabric sheet manufacturing step of impregnating a carbon fiber non-woven fabric sheet with a thermosetting resin before thermosetting,
A laminating step of laminating at least one carbon fiber non-woven fabric sheet on the surface of the expanded graphite sheet of the carbon fiber-based molded heat insulating material to which the expanded graphite sheet is attached to form a laminate.
A binding step of heating the laminate to a temperature higher than the thermosetting temperature of the thermosetting resin while pressurizing the laminate to bind the carbon fiber non-woven fabric sheet to the surface of the expanded graphite sheet.
A carbonization step of heat-treating the bound laminate in an inert gas atmosphere to carbonize the thermosetting resin, and
A method for manufacturing a molded heat insulating material with a surface layer having. 炭素繊維が交絡された炭素繊維構造体に熱硬化前の熱硬化性樹脂を含浸させてプリプレグとなすプリプレグ作製ステップと、
炭素繊維不織布シートに熱硬化前の熱硬化性樹脂を含浸させる樹脂含浸炭素繊維不織布シート作製ステップと、
前記プリプレグ上に膨張黒鉛シートを積層し、さらに前記膨張黒鉛シート表面に前記樹脂含浸炭素繊維不織布シートを少なくとも１つ積層して積層体となす積層ステップと、
前記積層体を加圧しつつ前記熱硬化性樹脂の熱硬化温度以上に加熱して、前記プリプレグ、前記膨張黒鉛シート、および前記炭素繊維不織布シートを結着する結着ステップと、
結着された前記積層体を不活性ガス雰囲気下で熱処理して、前記熱硬化性樹脂を炭素化させる炭素化ステップと、
を有する表面層付き成形断熱材の製造方法。A prepreg production step in which a carbon fiber structure in which carbon fibers are entangled is impregnated with a thermosetting resin before thermosetting to form a prepreg.
A resin-impregnated non-woven fabric sheet manufacturing step of impregnating a carbon fiber non-woven fabric sheet with a thermosetting resin before thermosetting,
A laminating step of laminating an expanded graphite sheet on the prepreg and further laminating at least one resin-impregnated carbon fiber non-woven fabric sheet on the surface of the expanded graphite sheet to form a laminate.
A binding step of binding the prepreg, the expanded graphite sheet, and the carbon fiber non-woven fabric sheet by heating the laminate to a temperature higher than the thermosetting temperature of the thermosetting resin while pressurizing the laminate.
A carbonization step of heat-treating the bound laminate in an inert gas atmosphere to carbonize the thermosetting resin, and
A method for manufacturing a molded heat insulating material with a surface layer having.
JP2019551119A 2017-10-30 2018-10-22 Molded heat insulating material with surface layer and method for manufacturing the same Active JP7198215B2 (en)

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