Overview
EN ISO 11468:1999 titled "Plastics - Preparation of PVC pastes for test purposes - Dissolver method (ISO 11468:1997)" is an international standard developed by the International Organization for Standardization (ISO) and adopted by CEN. It specifies a standardized methodology for preparing polyvinyl chloride (PVC) pastes using a dissolver apparatus, primarily for testing and characterizing PVC resin properties. This standard ensures consistent preparation of PVC pastes, critical for reliable rheological testing, quality control, and resin identification.
PVC pastes, or plastisols, are dispersions of PVC resin in plasticizer liquids. Proper preparation of these pastes using the dissolver method leads to uniform pastes suitable for rheological property analysis and comparison between different PVC resin batches. This method is essential for manufacturers, testing laboratories, and quality assurance professionals in the plastics and materials industry.
Key Topics
-
Scope and Purpose
EN ISO 11468:1999 applies a controlled process for preparing PVC pastes to standardize resin testing and characterization. It covers paste preparation from polymerized vinyl chloride resin employing a specific dissolver apparatus.
-
Dissolver Apparatus Design
The standard outlines a dissolver with a cylindrical, preferably double-walled mixing vessel, equipped with a motor-driven spindle attached to a toothed horizontal dissolver disc. The disc's design and spindle speed are specified to ensure consistent energy transfer to the paste, promoting homogeneous mixing.
-
Mixing Parameters
Variables such as disc diameter, number of teeth, spindle speed, mixing vessel size, and mixing time are established to optimize paste preparation. The standard provides tables detailing these parameters to accommodate different paste volumes.
-
Temperature Control
To prevent overheating (maximum 35°C during mixing), an external cooling system, such as a water-cooled double-walled vessel, is required. Maintaining the paste temperature within limits is critical to preserving paste properties.
-
Sample Conditioning and Preparation
PVC resin samples should be free of agglomerates and conditioned under specified standard atmospheric conditions (23°C, 50% relative humidity) to maintain moisture equilibrium prior to mixing.
-
Paste Composition
The standard allows preparation of standard pastes (e.g., paste A or B as referenced in ISO 1060-2) for resin designation. It also mentions preparations with other additives possible but not suitable for resin designation.
-
Deaeration
For viscosity measurements, the paste should be deaerated under partial vacuum to remove entrapped air, thus ensuring accurate rheological testing.
-
Reporting Requirements
A detailed paste-preparation report must document the procedures, formulations, paste temperature, resin identification, date, and any deviations to ensure traceability and repeatability.
Applications
-
PVC Resin Characterization and Quality Control
The dissolver method standardized in EN ISO 11468:1999 enables laboratories to prepare PVC pastes with reproducible properties. This is vital for evaluating resin rheology, comparing polymer batches, and verifying material consistency.
-
Research and Development
Formulators use this standard preparation technique to assess the effects of additives such as stabilizers or plasticizers on PVC paste properties and processing behavior.
-
Material Certification and Compliance Testing
Certification bodies and manufacturers can rely on this method to prepare test samples that comply with international requirements for PVC resin evaluation.
-
Production Process Optimization
Industrial mixers and process engineers may adapt parameters from this dissolver method for scaling up paste preparation, improving manufacturing consistency.
Related Standards
-
ISO 291:1997 - Plastics: Standard Atmospheres for Conditioning and Testing
Defines environmental conditioning used prior to PVC sample preparation.
-
ISO 1060-2: Plastics - Homopolymer and Copolymer Resins of Vinyl Chloride
Describes preparation of test specimens and property determination, including reference paste formulations related to this standard.
-
Additional Industry Standards on PVC Testing
Other ISO, CEN, or ASTM standards complement this method by covering rheological testing, thermal analysis, and physical property measurement of PVC materials.
Keywords: EN ISO 11468, PVC paste preparation, dissolver method, polyvinyl chloride paste, plastisol, PVC resin testing, plastics standard, rheological properties, PVC quality control, polymer testing method, PVC plastisol preparation, ISO PVC standard.
