BS 3412:1992 pdf download.General purpose polyethylene materials for moulding and extrusion.
2.1 Designation
2.1.1 The system given in 2.1.2 shall be used. The ethylene homopolymer and copolymer materials are classified according to their method of processing, their designatory properties, i.e. conventional density and melt flow rate, and supplementary information. The designation system is only intended to indicate a broad classification and in most circumstances specific values of the designatory properties and other characteristics will be required (see 2.2.2).
2.1.2 The designation shall consist of the following coded information, given in the following order and separated by a comma: a) the number and date of this British Standard, i.e. BS 3412:1992; b) identification of the plastics material, i.e. PE (polyethylene); c) the code as given in Table 1 corresponding to the intended application and method of processing; d) the code as given in Table 2 corresponding to additives and other supplementary information; e) designatory properties as coded in Table 3 and Table 4 separated by a hyphen. NOTE Figure 1 gives an example of a complete designation.
2.2.2 Additional properties Other properties to be selected will be determined by the characteristics required for processing and the characteristics required of the processed article. NOTE The purchaser should establish his own correlation between the properties of the processed article and the material properties required for their achievement. Typical additional properties to be measured and the test methods to be used are listed in Table 6.
2.3 Carbon black content The carbon black content of weather resistant material shall be not less than 2.0 % (m/m) and not more than 3.0 % (m/m) when determined by BS 2782:Method 452B.
2.4 Dispersion ofcarbon black and pigment 2.4.1 Carbon black The microscopic dispersion of carbon black shall be determined in accordance with BS 2782:Method 823A. The numerical rating shall be 5 or less and the uniformity of appearance in respect of smears and streaks shall be at least equal to photomicrograph A of Figure 1 of BS 2782:Method 823A:1978.
2.5.2 Contact with foodstuffs If the polyethylene is used in contact with foodstuffs, the antioxidants used therein shall be approved by the British Plastics Federation (BPF) and listed in the British Industrial Biological Research Association (BIBRA) Code of Practice as approved for use in contact with foodstuffs 1) .
2.5.3 Contact with water intended for human consumption Where polyethylene based products are used in contact with water intended for human consumption in applications covered by a British Standard, its requirements with respect to polyethylene based materials shall be met. If no standard exists, the material used in the application shall comply with BS 6920-1:1990, when tested by the methods contained therein.BS 3412 pdf download.