四フっ化樹脂

外観

白色の粉末

定義

本品は、テトラフルオロエチレンの重合体であり、次の化学式で表される。

溶解性

水にほとんど溶けない。

解説

ポリ(テトラフルオロエチレン)略称PTFE．デュポン(DuPont)社の製品名“テフロン”で広く知られている．白色のろう状の熱可塑性樹脂で，市販成形用ポリマーは分子量が大きく(400万～1000万)高い溶融粘度を示し，融点(327 ℃)も高いため，通常の成形が困難である．したがって，常温で粉末を圧縮固形化し，それを融点以上で焼結する粉末成形法およびペースト押出法が用いられる．－100 ℃ から260 ℃ までの広範囲の温度で使用でき，溶融アルカリ金属ならびに高温下フッ素ガス以外のすべての酸，アルカリ，溶剤に耐え，また電気特性もすぐれている．
森北出版「化学辞典（第2版）

用途

乾性潤滑剤、樹脂の表面改質剤。

化粧品の成分用途

滑沢剤、増量剤

効能

補綴補助 (人工血管, 眼窩底インプラント)

応用

ポリ(テトラフルオロエチレン)略称PTFE,は腐食性化学物質に使用できます，有機溶剤用のシール，パッキング，パイプをはじめ，ジェット機，航空機，無線機器などの電気絶縁材料などに使用される．

特長

Polytetrafluoroethylene (PTFE) particles provided in dry powder form. These particles require far less added dispersant than traditional PTFE particles to form stable dispersions.Microdispers particles are useful for many applications including coatings, gloss reducers, and coating additives that impact water pickup or surface energy.With good powder flow properties, these particles are easily compounded in a number of thermoplastic matrices with appropriate heat/shear mixing. Mean Particle Size: 3000nm (<10% of particle size distribution is above 10μm) (-CF2-CF2-)nWhite powderMolecular Weight: 20000mp 320-325ｰCSurface Area: 2平方メートル/g (BET surface area measurement)Surfactant Demand: Lower than traditional PTFE particles

説明

Tetrafl uoroethylene (TFE), also known as perfl uoroethylene, is a colorless, fl ammable, toxic gas. It is the monomer used for polytetrafl uoroethylene (PTFE), which is sold under the DuPont tradename of Tefl on. TFE is co-polymerized with other compounds to produce a variety of Tefl ons. TFE is produced by heating chlorodifl uoromethane (CHClF2, Freon-22) or trifl uoromethane (CHF3, Freon-23). TFE is used almost exclusively as a monomer in the production of PTFE. PTFE is a vinyl polymer, which means it is made from a monomer with carbon-carbon double bonds. PTFE is made from TFE by free radical polymerization.
PTFE’s unique physical properties are due to its chemical structure. PTFE consists of long chains of carbon atoms surrounded by fluorine atoms. The fluorine atoms act as a protective barrier that shields the carbon-carbon bond from chemical attack. The fluorine atoms repel other atoms, making it diffi cult for anything to stick to PTFE. PTFE resins have very low coeffi cients of friction (< 0.1). The strong fluorine-to-carbon bonds and high electronegativity of fluorine make PTFE very stable. The long chains of PTFE pack closely together to give a dense crystalline solid. The packing, which can be compared to stacking boards, produces little cross-linking.

化学的特性

white powder, or white solid with a slippery feel

来歴

The polymerized form of TFE was discovered accidentally by researchers at DuPont in 1938. During the mid-1930s, DuPont was investigating the development of new chlorofl uorocarbons (CFCs) for use as refrigerants. DuPont joined with General Motors to form a company called Kinetic Chemicals to combine their efforts in this area. Plunkett examined the properties of the substance. He discovered that the substance was inert to other chemicals, had a high melting point, and was very slippery. Plunkett also worked on duplicating the conditions necessary to produce it from TFE. He applied for a patent for polytetrafl uoroethylene polymers in 1939, which was granted in 1941 (U.S. Patent 2230654). He assigned the patent to Kinetic Chemicals. DuPont registered the term Tefl on in 1945 and introduced Tefl on products the next year.
Teflon is best known for its use in cookware, but its use in this area followed original industrial applications in gaskets, sealers, tape, and electrical insulation. Th ese applications were a direct result of the use of PTFE for military purposes during World War II.

使用

Poly(tetrafluoroethylene) is used in hundreds of applications in addition to cookware. Poly(tetrafluoroethylene) is used in inks, plastics, coatings, and lubricants.Poly(tetrafluoroethylene) can be molded into gaskets, seals, bearings, gears, and other machine parts. Poly(tetrafluoroethylene) is used as liners, insulation, membranes, and adhesives. Tefl on tape is commonly used in plumbing work. Poly(tetrafluoroethylene) is used to produce rainproof garments.

定義

ChEBI: A polymer composed of repeating tetrafluoroethyl groups.

製造方法

The preferred commercial method of preparation of polytetrafluoroethylene (PTFE) is by suspension polymerization. The details of the procedures employed have not been disclosed but it appears that two main processes are in use. In the first process, the conventional techniques of suspension polymerization are used to produce a granular product suitable for moulding and extrusion. The tetrafluoroethylene is polymerized under pressure in stainless steel autoclaves with a free radical initiator such as ammonium persulphate. The reaction is rapid and exothermic and requires careful control. The polymer granules are collected, washed and dried. In the second process, conditions are adjusted to give a dispersion of polymer of much finer particle size and lower molecular weight. The product may be stabilized and employed in latex form in such uses as film casting, coating and impregnation of fibres. Alternatively, the product may be coagulated to give a powder (often called 'dispersion polymer') used mainly for the extrusion of thin flexible sections.

調製方法

Polytetrafluoroethylene is generally made from tetrafluoroethylene gas by free-radical polymerization under pressure with oxygen, peroxides, or peroxydisulfates. The “granular resins” have medium-size particles that range from 30 to 600 mm. Colloidal aqueous dispersions, made by a different process, are concentrated to about 60% by weight of the polymer and have particles that average about 0.2 mm. Coagulated dispersions with agglomerates that average 450mm are also available .
The use of PTFE as a release agent in coatings and certain other food contact applications is permitted under FDA regulations .

一般的な説明

Poly(tetrafluoroethylene) is a fluoropolymer that is commercially known as PTFE. Its properties include high thermal stability, excellent chemical resistance, low dielectric constant and low surface energy. It is a hydrophobic polymer that is majorly used as a protective coating on the metal surface.

危険性

Evolves toxic fumes on heating. Question- able carcinogen.

健康ハザード

Fumes of heated polytetrafluoroethylene (PTFE) cause polymer fume fever, an influenza-like syndrome.

使用用途

PTFEは耐摩耗性、非粘着性、耐薬品性、耐熱性など様々な特徴を有する樹脂です。身近な用途としてはフライパンなどの調理器具のコーティングが挙げられます。一般的に「フッ素コート」と呼ばれるものは表面にPTFEがコーティングされています。

その他、工業的な用途としては高温環境下、腐食性の高い薬品を使用する環境下などの過酷な環境で用いられるホース、パッキン、チューブ、などが挙げられます。一方でPTFEは溶融粘度が非常に高いため、延伸、射出成形が難しく成形方法が限られており、他のフッ素系樹脂に比べて加工性は劣ります。

構造と樹脂製造方法

PTFEの化学構造はポリエチレンの水素がすべてフッ素に置き換わったものです。炭素とフッ素の結合は非常に強く、容易に分解することはありません。この性質がPTFEの耐熱性、耐薬品性の源となっています。

一方でPTFEは他のフッ素樹脂に比べて成形、加工性に劣ります。PFAなどの一般的なフッ素樹脂は加熱することで溶融し、流動性を示します。そのため、射出成形などの方法で整形することができます。一方でPTFEは融点を超えても非常に高粘度なままで、流動性を示しません。そのため、PTFEは粉末を圧縮成形し、融点以上の温度で焼成処理を行うことで成形します。

とテフロン違い

PTFEと混同されやすいフッ素樹脂として「テフロン」が挙げられます。テフロンとはアメリカの化学メーカーであるデュポン社の登録商標です。デュポン社がPTFEをテフロンという名前で商品化したため、PTFEとテフロンが同一と見なされがちになったという背景があります。

しかし、現在ではテフロンというのは様々なフッ素樹脂を総称する商品名であり、PTFE単独を指しているわけではありません。例えばFEP、PFAなどのフッ素樹脂や変性フッ素樹脂もテフロンとして販売されています。これらのフッ素樹脂は構造によって接着力や絶縁性、耐薬品性などが異なるため、用途に応じたフッ素樹脂を選定する必要があります。

耐熱温度と分解物安全性

PTFE自体は経口摂取に関する健康影響の報告は無く、調理器具から剥がれたコーティングの薄片を飲み込んだとしても影響が無いと考えられています。しかし、350℃以上の過加熱の状態になるとPTFEが熱分解して有害な化合物を生成する可能性があります。例えば鍋に火を掛けたまま寝てしまい、4時間から7時間後に呼吸器系の障害を発症したという例が報告されています。また、研究者が実験器具のを誤って過加熱してチューブが燃焼、発生した煙を吸い込んで喉の痛みを発症したという事例もあります。

通常の使用の範囲では人体に影響がないものの、長時間直接火に当たり続けたり、過加熱の状態が続くことで有害な分解物が発生する可能性はあるため、使用環境には十分な注意が必要です。

参考文献

工業用途

The polymer is insoluble, resistant to heat (upto 275°C) and chemical attack, and, in addition,has the lowest coefficient of friction of any solid.Because of its resistance to heat, the fabricationof polytetrafluoroethylene requires modificationof conventional methods. After molding thepowdered polymer using a cold press, the moldingsare sintered at 360 to 400°C by proceduressimilar to those used in powder metallurgy. Thesintered product can be machined or punched.Extrusion is possible if the powder is compoundedwith a lubricating material. Aqueoussuspensions of the polymer can also be used forcoating various articles. However, special surfacetreatments are required to ensure adhesionbecause polytetrafluoroethylene does not adherewell to anything.
Polytetrafluoroethylene (TFE resin) is usefulfor applications under extreme conditions ofheat and chemical activity. Polytetrafluoroethylenebearings, valve seats, packings, gaskets,coatings, and tubing can withstand relativelysevere conditions. Fillers such as carbon, inorganicfibers, and metal powders may be incorporatedto modify the mechanical and thermalproperties.
Because of its excellent electrical properties,polytetrafluoroethylene is useful when adielectric material is required for service at ahigh temperature. The nonadhesive quality isoften turned to advantage in the use of polytetrafluoroethyleneto coat articles such as rollsand cookware to which materials might otherwiseadhere.

安全性プロファイル

The finished polymerized compound is inert under ordinary condtions. There have been reports of “polymer fume fever” in humansexposed to pyrolysis products, whch also are irritants. Smohng should be prohibited in areas where ths material is being fabricated or, in general, where there may be dust from it. Exposure to pyrolysis or decomposition products appears to be the chief health-related problem. Questionable carcinogen with experimental tumorigenic data by implant. Incompatible with fluorine, sodmm potassium alloy. Under the proper conditions it undergoes hazardous reactions with boron, magnesium, or titanium. When heated to above 750°F it decomposes to yield highly toxic fumes of F-.

発がん性

Animal studies have not demonstrated that this polymer is carcinogenic. No data are available in humans. The polymer is not classifiable as to its human carcinogenicity. However, the EPA found that perfluorooctanoic acid (PFOA), a chemical used to produce PTEE is a “likely carcinogen.

環境運命予測

PTFE is the most stable of all TFE polymers and under physiological conditions does not release any components (IARC Monograph 74, 1999). PTFE is very inert chemically; only alkali metals and fluorine under pressure attack PTFE (Hazardous Substances Data Bank (HSDB)). There are no known ecotoxicological effects for PTFE (DuPont MSDS, 2011).