ASTM D 6576 – 07: Standard Specification for Flexible Cellular Rubber Chemically Blown

This is an ASTM International standard specification that establishes requirements for chemically blown cellular rubber materials used in miscellaneous applications. The standard covers two primary types of cellular rubber: Type I (open cell/sponge rubber) and Type II (closed cell/expanded rubber), each available in three grades (A, B, and C) based on oil and flame resistance requirements. Grade A offers oil and flame resistance; Grade B requires no oil or flame resistance; Grade C provides low-temperature resistance without oil resistance. Each type and grade is further divided into six compression deflection conditions ranging from super soft to firm, with specific compression deflection ranges measured in kPa and psi.

The specification establishes comprehensive physical property requirements detailed in Table 1, including compression deflection at 25% deflection, low-temperature flex resistance (ranging from -40°C to -55°C depending on grade), accelerated aging retention of at least 20% to 30%, recovery minimum of 60% to 90%, flame resistance, shrinkage, water absorption (Type II only), and oil aging resistance. Table 2 outlines optional requirements that can be added via suffix letters for flexing, color, density, and sulfur content. Dimension and tolerance requirements for sheet and strip forms, as well as molded or special shapes, are specified in Table 3, with separate parameters for sponge rubber and expanded rubber. The specification mandates compliance with referenced ASTM test methods (D 297, D 471, D 573, D 635, D 883, D 1056, D 3575) and includes mandatory government requirements for marking, age controls, quality assurance, sampling procedures, visual inspection, dimensional inspection, physical properties testing, packaging inspection, and packaging standards per MIL specifications. The specification explicitly states it does not address all safety concerns and places responsibility on users to establish appropriate safety and health practices.