ASTM D7050-04
Standard Practice for Rubber from Natural Sources-Sampling and Sorting Bales Based on Predicted Processing Properties

Standard No.

ASTM D7050-04

Release Date

2004

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D7050-04(2009)

Latest

ASTM D7050-04(2019)

Scope

In accordance with Specification D 2227, shipments of TSR10 and TSR20 must meet a minimum initial Wallace plasticity (Po) of 30 to be accepted. However, even with this minimum restriction, the uncured viscoelastic or “processability” properties are allowed to vary greatly. This variation in properties can significantly affect the quality and efficiency of a factory operation.

Bales of TSR10 or TSR20 which are lower in their uncured elastic quality (“soft” rubber) in some cases may impart better processing properties to tire innerliners, cushion gums, and sidewalls. “Soft” bales sometimes impart better building tack, better mold flow, and lower extrusion die swell with better dimensional stability. Also, these “soft” rubber bales may dissolve faster in solvents for adhesion dipping.

Bales of TSR10 or TSR20 that are higher in their uncured elastic quality (“hard” rubber) in some cases generate greater shearing during the initial stages of a factory mix, which result in a faster breakdown and a shorter mix cycle.

Therefore, in a factory operation, sometimes segregating TSR10 or TSR20 shipments into “soft” and “hard” categories can improve the efficiency and quality of a factory operation.

1.1 This practice covers the sorting of natural rubber bales of TSR10 or TSR20 in the factory according to their predicted processing performance based on differences in viscoelastic properties.

1.2 This practice determines which bales should be used in factory compounds which benefit from using "soft" natural rubber versus which work better with "hard" natural rubber.

ASTM D7050-04 Referenced Document

• ASTM D1485 Standard Test Methods for Rubber from Natural Sources-Sampling and Sample Preparation
• ASTM D2227 Standard Specification for Natural Rubber (NR) Technical Grades*， 2024-04-19 Update
• ASTM D3194 Standard Test Method for Rubber From Natural Sources-Plasticity Retention Index (PRI)
• ASTM D6204 Standard Test Method for Rubber8212;Measurement of Unvulcanized Rheological Properties Using Rotorless Shear Rheometers

ASTM D7050-04 history

• 2019 ASTM D7050-04(2019) Standard Practice for Rubber from Natural Sources—Sampling and Sorting Bales Based on Predicted Processing Properties
• 2004 ASTM D7050-04(2014) Standard Practice for Rubber from Natural Sourcesmdash;Sampling and Sorting Bales Based on Predicted Processing Properties
• 2004 ASTM D7050-04(2009) Standard Practice for Rubber from Natural Sources-Sampling and Sorting Bales Based on Predicted Processing Properties
• 2004 ASTM D7050-04 Standard Practice for Rubber from Natural Sources-Sampling and Sorting Bales Based on Predicted Processing Properties