Overview
ASTM D1823-24: Standard Test Method for Apparent Viscosity of Plastisols and Organosols at High Shear Rates by Extrusion Viscometer establishes a method to accurately measure the apparent viscosity of plastisol and organosol dispersions under high shear conditions. Plastisols and organosols, which are suspensions of finely divided polymers in plasticizers and solvents, are widely used in manufacturing processes such as coating, molding, and spraying. Understanding their viscosity at high shear rates is essential for determining material suitability for specific processing methods, ensuring optimal product performance and consistent quality.
Key Topics
- High Shear Rate Measurement: The test method utilizes an extrusion viscometer to determine the flow properties of plastisols and organosols when subjected to high shear rates, simulating conditions encountered during industrial processing.
- Material Applicability: Primarily used for poly(vinyl chloride) (PVC) plastisols and organosols, but applicable to other dispersion resins requiring viscosity assessment under extrusion or similar processing.
- Process Relevance: Viscosity measurements are directly relevant to mixing, pumping, knife coating, roller coating, spray applications, and other high-shear manufacturing processes.
- Test Conditions: Includes steps for sample conditioning, apparatus setup, pressure application, collection of extrudate, and cleaning, ensuring standardized and repeatable results.
- Data Reporting: The method defines requirements for reporting sample identification, test temperatures, conditioning details, and resulting viscosity data at specified pressures and shear rates.
Applications
The ASTM D1823-24 test method is crucial for industries that manufacture, process, or utilize plastisols and organosols, especially those based on PVC resins. Key practical applications include:
- Quality Control: Ensures incoming raw materials and final formulations meet viscosity specifications for reliable processing and end-use performance.
- Formulation Development: Assists in optimizing resin, plasticizer, and additive ratios for targeted viscosity and flow properties, enhancing product consistency.
- Process Optimization: Provides insights into how materials will behave in high shear environments, supporting decision-making for equipment selection and processing parameters.
- Troubleshooting: Detects inconsistencies or deviations in material behavior that can indicate batch variation, equipment issues, or formulation problems.
- Regulatory and Contract Compliance: Delivers standardized data for technical documentation and meets quality assurance requirements in global trade and procurement.
Related Standards
The following standards are commonly referenced alongside or compared to ASTM D1823-24 for apparent viscosity measurement and related material property evaluations:
- ASTM D1824: Covers the measurement of apparent viscosity of plastisols and organosols at low shear rates.
- ASTM D883: Terminology relating to plastics, supporting consistent interpretation of test results across standards.
- ASTM D1475: Standard Test Method for Density of Liquid Coatings, Inks, and Related Products, relevant for calculating viscosity.
- ASTM D1755: Specification for Poly(Vinyl Chloride) Resins, providing guidance on material preparation.
- ISO 4575:2007: Poly(vinyl chloride) pastes - Determination of apparent viscosity using the Severs rheometer; addresses the same subject matter as this ASTM standard, but with differing technical content.
- ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method.
- ASTM E2935: Practice for Evaluating Equivalence of Two Testing Processes, relevant for cross-laboratory comparisons.
ASTM D1823-24 delivers a reliable protocol for high shear viscosity testing of plastisols and organosols, underpinning material development, process engineering, and quality assurance activities in the plastics and coatings industries.