GB/T 41943-2022Natural rubber in bales - Determination of the amount of bale coating (English PDF)

3.2.7 of ISO 1434.2016;

--- 6.1 corresponds to Chapter 4 of ISO 1434.2016, adding 6.2;

---7.1 corresponds to Chapter 5 of ISO 1434.2016, adding 7.2;

---Appendix A corresponds to Appendix B of ISO 1434.2016, and Appendix B corresponds to Appendix A of ISO 1434.2016.

Compared with ISO 1434.2016, this document has many technical differences, and the vertical single

Lines (|) are marked. The technical differences and their reasons are as follows.

---Changed the scope expression and deleted the "ashing method is the preferred method" (see Chapter 1, Chapter 1 of ISO 1434.2016), because the gray

The precision of the chemical method is not much different from that of the brush or scrape method;

--- Changed the sample preparation regulations (see 4.2, 2.2 of ISO 1434.2016) to simplify the requirements;

--- Changed the principle of the ashing method (see 5.1, 3.1 of ISO 1434.2016) to make the expression more reasonable;

---Changed the volume of the crucible (see 5.2.2, 3.2.2 of ISO 1434.2016) to comply with commercially available specifications;

--- Changed the accuracy of the analytical balance (see 5.2.3, 3.2.3 of ISO 1434.2016) to meet the requirements of the test procedure;

--- Deleted "Bunsen burner" (see 3.2.4 of ISO 1434.2016) and "dryer" (see ISO 1434.2016) in "instrument"

3.2.5), adding a balance with an accuracy of 0.1g (see 5.2.4) to adapt to the change of the test procedure;

---Changed the test procedure (see 5.3, 3.3 of ISO 1434.2016) to enhance operability and facilitate the application of this document;

--- The normative reference document GB/T 4498.1-2013 (see 5.3) has been added to refer to the ready-made method in the test procedure;

--- Added a test procedure (see 6.2) and result presentation (see 7.2) of a brushing or scraping method for selection;

--- Increase the rounding off requirements of test results (see Chapter 7) to improve the operability of judgment;

--- Delete the allowable difference (see Chapter 5 of ISO 1434.2016) to conform to the actual situation in our country.

Please note that some contents of this document may refer to patents. The issuing agency of this document assumes no responsibility for identifying patents.

4.1 General

The larger the number of samples taken, the more representative of the batch of goods.

In most cases, reasonable limits should be set according to the actual situation.

The number of plastic bales randomly selected shall be agreed upon by the supplier and the purchaser.

NOTE. When applicable, statistical sampling plans selected from ISO 3951-2 can be used.

4.2 Sample preparation

Randomly select the film for wrapping from any three adjacent sides of the plastic bag, one film for each side, and then use the sample punching die

(5.2.1) Punch out three test pieces of 50mmx50mm respectively.

If the ashing method is used, the thickness of the sample should not exceed 4mm.