Rubber Process Analyzer (RPA)

ASTM D6204 and ASTM D6601

The rubber process analyzer is an extremely important tool for product research and development across every industry that uses rubber materials. The RPA measures the viscoelastic properties of both polymers and elastomeric compounds. Data is gathered before and after cure.

This test method informs production decisions by providing precise information about your sample, like its processability, cure characteristics and speed, and after-cure behavior.

ACE’s rubber process analyzer uses standard test methods from the American Society for Testing and Materials (ASTM) to deliver consistent, credible results that are consistent across all standards.

When you understand your materials’ processing characteristics, you can streamline your methods for the most efficient rubber processing possible. ACE’s rubber industry experts are available and ready to analyze this data. Together, we can increase the quality of your product while increasing production efficiency.

Rubber Process Analyzer Test Methods

ACE’s RPA can be used to characterize a wide range of materials, including polymers, raw materials, basic, finished, and cured compounds, making it a versatile tool that can be used across industries. Its testing capabilities and the data drawn from those tests are also versatile. Working with our responsive and expert staff members, you can design a course of testing that is tailored to your distinct goals and challenges.

ACE’s rubber process analyzer is capable of a wide variety of test methods, including the popular ASTM D6204 and ASTM D6601 test methods.

ASTM D6204

This test method measures the viscoelastic properties of both raw rubber and uncured rubber compounds.

To measure these properties, ASTM D6204 involves the use of a rotorless oscillating shear rheometer, which measures the flow properties of raw rubber and unvulcanized rubber compounds.

Your rubber sample will be held at an elevated temperature and exposed to strain in order to test the sample’s viscoelastic qualities. We can measure these qualities with a frequency sweep, a strain sweep, a temperature sweep, or with a timed test.

    • Frequency sweep: frequency changes in steady steps while temperature remains the same
    • Strain sweep: strain changes in steady steps while frequency and temperature remain the same
    • Temperature sweep: temperature increases or decreases in steady steps while frequency and strain remain the same
    • Timed test: strain is applied for a predetermined period of time while strain amplitude, frequency, and temperature remain the same

The best course of testing for your sample will depend on your material’s unique needs. ACE can also perform multiple sweeps to gain an even greater understanding of your raw or unvulcanized rubber’s viscoelastic qualities.

These flow properties are important to understand for factory processing purposes.

ASTM D6204 Applications

This test method reveals the viscoelastic and flow properties of raw rubber and unvulcanized rubber compounds. These properties relate to a material’s processing behavior in a factory, making them important to understand if you are looking to streamline your factory processing methods.

This method may also be used for quality control and research and development. For example, with ASTM D6204, ACE can evaluate the compound differences that occur when using different compounding materials in your rubber product.

ASTM D6601

ASTM D6601, like ASTM D6204, uses the RPA’s rotorless oscillating shear rheometer, this time measuring cure dynamic properties at a predetermined temperature below the cure temperature. Measurements may be taken at multiple temperatures to produce a range of characteristic data. The method also covers specified cure conditions comparable to static cure in order to minimize effects on the dynamic properties of cured rubber compounds.

This test method is used to determine the vulcanization characteristics of rubber compounds. This determination occurs under selected test conditions designed to simulate the manufacturing process, which will depend on your material, your manufacturing process, and the goals of testing. The test conditions will not affect the cured dynamic properties of your sample, therefore ensuring test results are consistent and applicable to real-life use.

ASTM D6601 first measures the viscoelastic properties of a sample at an elevated cure temperature, measuring its properties as the material cures. This first sweep measures strain softening and material interactions.

After a predetermined cure time, the test method then also measures the dynamic properties of the vulcanizate at a temperature significantly lower than the cure temperature. This second sweep determines the breakdown of polymers and fillers caused by the first sweep.

Measurements taken at these low temperatures during the second sweep effectively relate to rubber product end-use service conditions, and are therefore useful for research and development. The temperature conditions during testing can be tailored to produce results most relevant to your industry, product development goals, and product end-use.

ASTM D6601 Applications

Like ASTM D6204, this test method is often used for quality control and research and development. ASTM D6601 is appropriate for rubber compounds containing curatives.

This method is also useful if you are interested in evaluating the differences in cure and dynamic properties when using different compounding ingredients.

ASTM D6601 is not recommended for compounds based on silicone or fluoroelastomers, which due to high levels of thermal contraction or poor adhesion may slip during parts of the testing process. This slippage causes results to be unreliable, so an alternative course of testing is recommended.

Research and Development Analysis from Rubber Experts at ACE

At ACE Laboratories, we understand that the research and development and quality control processes can be daunting. Our industry experts are committed to helping you maximize your production efficiency with high quality, repeatable, and accurate rubber testing. Our ISO/IEC 17025 independent accredited laboratory ensures that your testing results are credible and widely accepted.

Reach out and contact us today to take your products and manufacturing processes to the next level.

ACE is an ISO/IEC 17025 Accredited Independent Laboratory

ANAB is an internationally recognized accrediting organization that assures technical expertise and global acceptance of ISO/IEC 17025 accredited laboratories’ test reports for the purposes of free trade and regulatory acceptance.