GB/T 8293-2019Rubber latex, natural, concentrate - Determination of sludge content (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 8293-2008 "Determination of the content of concentrated natural rubber latex residue", compared with GB/T 8293-2008, the main

The technical changes are as follows.

--- The scope of Chapter 1 adds "natural latex that does not necessarily apply to other sources; does not apply to latex or vulcanized latex";

--- Change the ISO /T R9272 in the normative reference in Chapter 2 to the reference (see References, No. 2 of the.2008 edition)

chapter);

--- Change "12000m/s2, equipped with two 50mL conical centrifuge tubes" to "12000m/s2 (1200g), equipped with two

50mL conical centrifuge tube or round centrifuge tube" (see 5.1,.2008 version 5.1);

--- Change the "pipette" to "pipette or pipette" (see 5.2, 5.2 of the.2008 edition);

--- Increased requirements for "oven" and "balance" (see 5.3, 5.4);

--- "Dry at 70 °C +/- 2 °C, until the weight loss is less than 1mg in 30min" to "more than 70 °C +/- 5 °C temperature

Dry until the mass is reduced by less than 1 mg" (see Chapter 7, Chapter 7 of the.2008 edition);

--- Revised the representation method of the residue content calculation formula (see Chapter 8, Chapter 8 of the.2008 edition);

--- Change the precision clause to informative Appendix A "Precision" and update the precision data (see Chapter 9 and Appendix)

A, Chapter 9 of the.2008 edition).

This standard uses the redrafting method to modify the ISO .2005.2014 "Determination of the content of concentrated natural rubber latex residue".

The technical differences between this standard and ISO .2005.2014 and their reasons are as follows.

--- Regarding the normative reference documents, this standard has made technical adjustments to adapt to the technical conditions of China. Adjustment

The situation is reflected in Chapter 2, "Regulatory Citations", and the specific adjustments are as follows.

* Replace ISO 123 with GB/T 8290 modified to international standards (see Chapter 6).

--- Added "warning" to comply with the provisions of GB/T 20001.4-2015.

--- Change the "pipette" to "pipette or pipette", because the pipette is also a common instrument (see 5.2, ISO .2005..2014 5.2).

--- Increased requirements for "oven" and "balance" to better standardize test conditions (see 5.3, 5.4).

--- Modified the residue formula calculation formula to meet the requirements of GB/T 1.1-2009 (see Chapter 8).

--- Added "The test results are expressed as the average of the results of duplicate measurements" to facilitate the use of this standard (see Chapter 8).

This standard was proposed by the China Petroleum and Chemical Industry Federation.

This standard is under the jurisdiction of the National Rubber and Rubber Products Standardization Technical Committee (SAC/TC35).

This standard was drafted. Agricultural Products Processing Institute of China Academy of Tropical Agricultural Sciences, Hainan Natural Rubber Quality Inspection Station, Guangdong Inspection

Quarantine Technology Center, Hainan Natural Rubber Industry Group Co., Ltd.

1 Scope

This standard specifies the method for determining the content of concentrated natural latex residue.

This standard applies to natural rubber latex from Brazilian trefoil trees and may not be suitable for natural latex from other sources.

This standard does not apply to latex or vulcanized latex.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article.

Pieces. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 8290 concentrated natural latex sampling (GB/T 8290-2008, ISO 123.2001, MOD)

3 Principle

The sample was centrifuged, and the resulting residue was repeatedly washed with an ammonia-ethanol solution and then dried to a constant mass.

4 reagents

Use only validated analytical reagents, distilled water or water of equivalent purity.

5 instruments

Laboratory routine instruments and the following instruments.

5.1 centrifuge, producing an average acceleration of about 12000m/s2 (1200g), equipped with two 50mL conical centrifuge tubes or round

Heart tube.

5.2 Pipette or straw, the capacity is appropriate, the diameter of the lower mouth is about 2mm.

6 sampling

Sampling according to the method specified in GB/T 8290.