ポリ（オキシメチレン） 化学特性,用途語,生産方法
解説
ポリ(オキシメチレン)略称POM．ポリホルムアルデヒド，アセタール樹脂ともよばれ，
の一般式で示される化合物．合成法は古くから知られていたが，熱安定性に欠けるため，実用化されていなかった．しかし，原料であるホルムアルデヒドをよく精製し，末端基をヘミアセタール形の-OH基から，
にかえて安定化させることによって実用化に成功し，フィルムなどとして製品化されている．ホルムアルデヒドのかわりに，精製が容易なトリオキサン(ホルムアルデヒドの三量体)を用いることもある．合成法は，ホルムアルデヒドあるいはトリオキサンと0.003～0.1重量％ 程度の三フッ化ホウ素を，30 min～5 h，50～90 ℃ で反応させ，その後，無水酢酸中でピリジンなどを触媒として，エステル化する．性質としては，耐油，耐水，耐化学薬品性がすぐれているばかりではなく，強靭で，熱変形温度も高く，数々のすぐれた特長をもっている．
化学的特性
Polyoxymethylene (POM), also known as acetal or polyacetal, is a high-performance engineering thermoplastic valued for its strength, stiffness, and low friction. This semi-crystalline polymer offers excellent dimensional stability and wear resistance, making it ideal for precision parts in mechanical and automotive applications.
Thermal stability: POM possesses an excellent thermal stability, which can endure temperature changes without significant loss of physical properties. This stability makes it ideal for parts requiring high precision and dimensional stability.
Chemical resistance: The material is resistant to a wide variety of solvents and chemicals, including neutral chemicals, aliphatic hydrocarbons, and most oils and greases.
Ultimate Tensile Strength 69 - 83 MPa
Yield Tensile Strength 65 - 69 MPa
Ultimate Compressive Strength 110 MPa
Young’s Modulus (E) 2.9 - 3.2 GPa
Flexural Modulus 2.41 - 3.10 GPa
Elongation at Break 40 - 75%
Rockwell Hardness (R) 120
Melting Point 175 °C
Thermal Conductivity 0.37 W/m·K
Specific Heat Capacity (Cp) 1464 J/kg·K
Coefficient of Thermal Expansion (αL) 8.5×10-5 1/°C
Relative Permittivity (@1 MHz) (εr) 3.8
Electrical Resistivity 1015 Ω·cm
Dielectric Field Strength (Ed) 200 kV/cm
使用
Acetal resins, also known as polyoxymethylene and polyformaldehyde, are polymers of pure formaldehyde with unusually good mechanical properties. They are resistant to elongation and impact and replace light metals in many uses. The finished polymer has not been related to adverse health effects in humans or animals. They can be thermally degraded, for example, in an overheated molding machine, to produce formaldehyde gas, with its well-recognized irritant and sensitizing properties.
定義
ChEBI: A poly(alkylene oxide) macromolecule, composed of repeating methyleneoxy units.
工業用途
Polyoxymethylene, or polyacetal, resins arepolymers of formaldehyde. With high molecularweights and high degrees of crystallinity, theyare strong and tough and are established in thegeneral class of engineering thermoplastics.
Although somewhat similar to polyethylenein general molecular structure, polyacetal moleculespack more closely, and attract each otherto a much greater extent, so that the polymer isharder and higher-melting than polyethylene.Polyacetals are typically strong and tough,resistant to fatigue, creep, organic chemicals(but not strong acids or bases), and have lowcoefficients of friction. Electrical properties arealso good. Improved properties for particularapplication may be attained by reinforcementwith fibers of glass or polytetrafluoroethylene.
The combination of properties has led tomany uses such as plumbing fittings, pump andvalve components, bearings and gears, computerhardware, automobile body parts, andappliance housings. Other aldehydes may bepolymerized in a similar way.
ポリ（オキシメチレン） 上流と下流の製品情報
原材料
準備製品