【国外标准】 Standard Specification for Polyethylene Plastics Extrusion Materials for Wire and Cable

This specification provides for the identification of polyethylene plastics extrusion materials for wire and cable in such a manner that the seller and the purchaser can agree on the acceptability of different commercial lots or shipments. The polyethylene plastics are identified primarily on the basis of two characteristics, namely, density and flow rate (previously identified as melt index). The former is the criterion for assignment as to type which are as follows: Type 0,Type I, Type II, Type III, and Type IV, the latter for designation as to category which are: Category 1,Category 2, Category 3,Category 4, and Category 5. Other attributes important for certain applications are covered by three general classes and by specifying in greater detail, by grades, a minimum number of key characteristics covered too broadly or not at all by the type, class, and category designations. Each of five types and categories is subdivided into four classes according to composition and use as follows: Class A, Class B, Class C, and Class D. In addition, the materials can be classified into different grades namely Grade E1, Grade E2, Grade E3, Grade E4, Grade E5, Grade E6, Grade E7, Grade E8, Grade E9, and Grade E10. The extrusion material for wire and cable shall be polyethylene plastic in the form of powder, granules, or pellets. The extrusion materials for wire and cable shall be as uniform in composition and size and as free of contamination as can be achieved by good manufacturing practice. Different tests shall be conducted in order to determine the following physical properties of extrusion materials: tensile stress, elongation, brittleness temperature, environmental stress-crack resistance, thermal stress-crack resistance without cracking, dissipation factor before and after milling, dielectric constant, volume resistivity, water immersion stability, absorption coefficient, weatherability for colored materials, and carbon content.1.1 This specification provides for the identification of polyethylene plastics extrusion materials for wire and cable in such a manner that the seller and the purchaser can agree on the acceptability of different commercial lots or shipments. The tests involved in this specification are intended to provide information for identifying materials according to the types, classes, categories, and grades covered. It is not the function of this specification to provide specific engineering data for design purposes.1.2 This specification does not allow for the use of recycled plastics (see Note 3).1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.1.4 The following safety hazards caveat pertains only to the test method portion, Section 12, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.NOTE 1: There is no known ISO equivalent to this standard.NOTE 2: This standard has undergone major revision from the reapproval of 1989 and now covers only polyethylene for wire and cable applications. For information regarding molding and extrusion materials, see Specification D4976. For information regarding plastic pipe materials, see Specification D3350.NOTE 3: See Guide D7209and 3.1.2 of this standard for information and definitions related to recycled plastics.