Significance and Use

The particulate size distribution of vulcanizate particulate rubber is used for the purpose of assigning a product mesh or average particle size designation.

The product designation for mesh size for the Ro-tap method (Method A, as follows) is based on the size designation screen which allows a range for the upper limit retained of maximum 5 % for up to 850 ? m (20 mesh) particles, maximum 10 % for 600 to 150 ? m (30 to 100 mesh), and maximum 15 % for 128 to 75 ? m (120 to 200 mesh). No rubber particles shall be retained on the zero screen (see Table 1, Classification D5603 ).

For Method A, the weight percent retained on a specific screen is noted whereas in Method B (ultrasonic technique), the number of particles at a particular size is counted.

Method B addresses problems that may be caused by tackiness and static electrical forces that recycled rubber particles exert on each other to form agglomerates, especially for 80 mesh or finer particles. This method eliminates agglomerate formation by ultrasonically dispersing the particles.

Both methods can be used as a quality control tool.

1. Scope

1.1 These test methods describe the procedures for determining average particle size distribution of recycled vulcanizate particulate.

1.2 Method A describes the Ro-tap sieve test method for 60 mesh or coarser particles.

1.3 Method B describes the ultrasonic technique combined with optical microscope especially suitable for 80 mesh or finer particles. This procedure is based on Test Method D3849 .

1.4 The values stated in SI units are to be regarded as the standard.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D297 Test Methods for Rubber Products--Chemical Analysis

D1416 Test Methods for Rubber from Synthetic Sources--Chemical Analysis

D1566 Terminology Relating to Rubber

D3182 Practice for Rubber--Materials, Equipment, and Procedures for Mixing Standard Compounds and Preparing Standard Vulcanized Sheets

D3191 Test Methods for Carbon Black in SBR (Styrene-Butadiene Rubber)--Recipe and Evaluation Procedures

D3192 Test Methods for Carbon Black Evaluation in NR (Natural Rubber)

D3849 Test Method for Carbon Black--Morphological Characterization of Carbon Black Using Electron Microscopy

D5603 Classification for Rubber Compounding Materials--Recycled Vulcanizate Particulate Rubber

E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves

E105 Practice for Probability Sampling of Materials

Keywords

particle size distribution; recycled vulcanizate particulate rubber; ultrasonic light optical microscopic technique; Particle analysis--rubber materials; Rubber compounding materials; Vulcanized rubbers;

ICS Code

ICS Number Code 83.060 (Rubber)

DOI: 10.1520/D5644-01R08E01

ASTM International is a member of CrossRef.

ASTM D5644