GB/T 5577-2022Specification for the codification of synthetic rubber (English PDF)

4.1 General

The codification of synthetic rubber is composed of three character groups: synthetic rubber code, main features, and additional features added as needed. Each character group is separated by a space. The codification is constructed based on the following pattern: Character group 1: Synthetic rubber code (see 4.2).

Character group 2: Feature information, represented by three or four Arabic numerals (see 4.3).

Character group 3: Optional additional information for further classification purposes (see 4.4).

4.2 Character group 1

In this character group, the synthetic rubber code shall comply with the provisions in GB/T 5576.

For modified products of synthetic rubber and other synthetic materials, the code shall be composed of the code of synthetic rubber and the code of other synthetic materials.

The code of each material is separated by a symbol "/". Fox example, the code of nitrile rubber/polyvinyl chloride co-precipitated rubber is "NBR/PVC".

For liquid rubber, add L before the rubber code and separate with "-", such as "L-NBR".

For powder rubber, add P before the rubber code and separate with "-", such as "P- NBR".

4.3 Character group 2

In this character group, the main features of synthetic rubber are represented by feature information. Each feature information can be represented by one or two numbers. The main feature information of different kinds of synthetic rubber shall comply with the provisions of Appendix A. Further provisions for the main feature information shall be in accordance with Appendix B.

4.4 Character group 3

This character group is optional. Add relevant additional information as needed, such as purpose, appearance, etc.

B.4 Ethylene-propylene copolymer (EPM)

The first and second digits of EPM character group 2 represent the median Mooney viscosity. The third and fourth digits represent the first two digits of the median vinyl content. For example, an ethylene-propylene copolymer, its Mooney viscosity is 20; the mass fraction of ethylene content is 50%; its codification is EPM 2050.

B.5 Isobutylene-isoprene rubber (IIR)

The first and second digits of IIR character group 2 represent the first two digits of the median unsaturation value. The third and fourth digits represent the median Mooney viscosity. For example, an isobutylene-isoprene rubber; the mole fraction of degree of unsaturation is 1.7%; its Mooney viscosity is 51; its codification is IIR 1751.

B.6 Halogenated isobutylene-isoprene rubber (BIIR or CIIR)

The first and second digits of BIIR or CIIR character group 2 represent the first two digits of halogen content. The third and fourth digits represent the median Mooney viscosity. For example, a brominated isobutylene-isoprene rubber; the mass fraction of its bromine content is 2.0%; its Mooney viscosity is 32; its codification is BIIR 2032.

B.7 Acrylonitrile-butadiene rubber (NBR)

The first and second digits of NBR character group 2 represent the first two digits of the median value of bound acrylonitrile content. The third and fourth digits represent the median Mooney viscosity. For example, a nitrile rubber, the mass fraction of bound acrylonitrile content is 33%; the Mooney viscosity is 45; its codification is NBR 3345.