Representative Examples of The Polyoxymethylene Are > 자유게시판

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The tetrafluoroethylene-hexafluoropropylene copolymer is prescribed in ASTM D 2116, and has four sorts, i.e. Type I to Type IV. The tetrafluoroethylene-perfluoroalkylvinyl ether copolymer is prescribed in ASTM D 3307, and has two types, i.e. Type I and type II. The tetrafluoroethylene perfluoroalkylvinyl ether copolymer and the tetrafluoroethylenepentafluoroproylene copolymer will be employed in an extrusion molding by heating to melt. Among them, polytetrafluoroethylene, tetrafluoroethyleneperfluoroalkylvinyl ether copolymer and tetrafluoroethylene-hexafluoroethylene copolymer, particularly, polytetrafluoroethylene are preferably used as a result of they are wonderful in thermal resistance, load efficiency and flexibility. The polybutylene terephthalate additionally has a characteristic that the distinction of the preliminary load efficiency and the load effectivity after the management cable is operated for a long period of time is small. The high density polyethylene has wonderful physical properties equivalent to high load efficiency. They purchase them by the pallet load heaps, maybe 40-eighty pallets per lot and as many as a dozen heaps or extra in anyone public sale.

The polyoxymethylene also has properties such as low stickslip below a high load and improves the operationability of a control cable. When the melt index of the polyoxymethylene is less than 0.5 g/10 minutes, moldability deteriorates because there is a necessity to heat the polyoxymethylene to close by a temperature of the thermal decomposition. The cut up graphite rings in the channels present thermal contact with the graphite bricks of the stack. The polybutylene terephthalate is excellent in thermal resistance, oil resistance and abrasion resistance, and has a low coefficient of friction. It is preferable to use the sort III and sort IV as a result of the kind I and kind II having a small polymerization diploma are poor in stress-cracking resistance. The kind II has a polymerization degree higher than the sort I, and is superb in stress-cracking resistance. The smaller the melt index of the polybutylene terephthalate is, the greater the durability reminiscent of abrasion resistance and stress-cracking resistance is, however it tends to be difficult for carrying out the extrusion molding. Because the polyphenylene sulfide is generally poor in elongation and adaptability as it's, it is preferable to make use of a polyphenylene sulfide containing 5 to 40% by weight of an elastomer.

It's preferable that the elastomer has an capability to be modified so that a softened polyphenylene sulfide, which is prepared by mixing with the elastomer and kneading them with melting, has a flexural modulus of at most 30000 (ASTM D 790) and a tensile elongation at break of at the least 5% (ASTM D 638). Representative examples of such an elastomer are, as an illustration, an olefin copolymer containing an epoxy group (ethylene content material: 88% by weight, glycidyl methacrylate content material: 12% y weight), a hydrogenated styrenebutadience copolymer (TUFTEC M 1913 commercially available from Asahi Chemical Industry Co., Ltd.), an ethylene-propylene copolymer (TAFMER PO 680 commercially obtainable from MITSUI PETRO CHEMICAL INDUSTRIES, LTD.), and the like. Examples of the thermoplastic resin are, for example, polybutylene terephthalate, excessive density polyethylene, polyoxymethylene, a fluorocarbon resin represented by polytetrafluoroethylene, a polyamide represented by 6,6-nylon, polyphenylene sulfide, and the like, but the present invention is just not limited by the exemplified ones. Representative examples of the polyamide are, for example; 6,6-nylon, 6-nylon, 11-nylon, 12-nylon, and the like. As the examples of the polybutylene terephthalate, ones used in the liner might be exemplified. For kids, the effects could be expected at half these dose levels.

Rad: Or, Radiation Absorbed Dose acknowledges that completely different materials that obtain the same publicity might not absorb the identical quantity of power. For gamma rays and beta particles, 1 rad of publicity ends in 1 rem of dose. The R/hr in the ranges indicated below refers to Roentgen per hour publicity price. Since most Americans do not know what size of radiation doses would incapacitate or kill them, and do not even know that a milliroentgen is 1/1000 of a roentgen, some folks buy instruments which can be capable of measuring most dose rates of only one roentgen or less per hour. Also, when the melt index is too massive, the polybutylene terephthalate lacks toughness and cracks are generated within the inside coat, and the liner is usually damaged when the internal coat is rapidly bent within the assembling technique of a management cable. Among them, polyoxymethylene is ideally utilized in the current invention as a result of a stickslip is hardly generated when polyoxymethylene is used.