ASTM D1823 Standard Test Method for Apparent Viscosity of Plastisols and Organosols at High Shear Rates by Extrusion Viscometer

Get Certified ASTM D1823 Testing for Reliable Plastisol Viscosity Assessment

Viscosity directly influences the processing properties of plastisols and organosols. ASTM D1823 testing confirms that these materials fall within the viscosity range required for coating, molding, and sealing. Accurate and reproducible data for quality control, formulation development, or process optimization are available with qualified laboratory testing. This testing is useful for manufacturing consistency and for keeping industries consistent in product performance for vinyl coatings, sealants, and automotive use.

The scope of ASTM D1823 includes:

• Material type: ASTM D1823 applies to plastisols and organosols, which consist of dispersions of vinyl chloride resins in plasticizers, whether volatile organic liquids are present or not.
• Purpose: ASTM D1823 measures the apparent viscosity of plastisols and organosols at shear rates that occur in processing operations like spreading, coating, and molding. 
• Property measured: The test measures apparent viscosity, based on the pressure required to extrude the product, orifice size, and flow rate, and is usually expressed in poise or pascal-seconds.
• Method: The method is an ASTM D1823 extrusion viscometer in which the product is extruded through a calibrated orifice under specific pressure and temperature conditions.
• Result: The testing laboratory obtains apparent viscosity values from the materials it tests.
• Test Limitations: Apparent viscosity is measured at one shear rate; values may not apply to the flow behavior over all processing conditions.
• Environmental conditions: The test is conducted under controlled temperature conditions as specified in the standard.
• Applications: Engineers apply ASTM D1823 for quality control, formulation development, and process optimization in coatings, sealants, and vinyl product manufacturing. 

What are the Uses of ASTM D1823 Testing?

ASTM D1823 testing provides results that help labs obtain accurate viscosity data for plastisol and organosol quality control. These results are important to manufacturers and engineers for formulation development, quality control, and process optimization.

This standard has applications in-

• The evaluation of the flow behavior of plastisols under high shear rates.
• Assisting with quality control of the vinyl coating and molding process
• Evaluating viscosity differences across formulations.
• Helping to optimize processes in spreading, coating, and molding
• Communicating information for product design and material choice.
• Monitoring batch-to-batch consistency in plastisol production. 

Which materials can be tested under ASTM D1823?

ASTM D1823 covers plastisols and organosols, which are fluid dispersions of vinyl chloride resins in plasticizers, with or without volatile organic liquids. The test method is used for materials such as coatings, sealants, molded products, and automotive applications. The test is used to assess a material flowing through a calibrated orifice under controlled conditions of pressure and temperature. 

Why is ASTM D1823 Important?

ASTM D1823 gives a standard test method for measuring the apparent viscosity of plastisols and organosols at elevated shear rates. This test method is especially helpful in establishing the viscosity properties of these materials under simulated processing conditions like spreading, coating, and molding. Viscosity influences the flow properties, coating thickness, and final product properties of plastisols. This standard facilitates quality control, aids in formulation development, and aids in the maintenance of consistent processing behavior between production batches. 

ASTM D1823 Testing Process and Data Collection

The testing process starts with preconditioning the plastisol or organosol sample at the test temperature. The analyst places a conditioned sample in the extrusion viscometer reservoir. The analyst forces the material through the calibrated opening under controlled pressure. Technicians measure the extrusion rate or the time required to extrude a given amount of material. The data acquisition system is used to store the extrusion pressure, flow rate, and test temperature. Apparent viscosity is calculated from the extrusion pressure, orifice size, and flow rate. The laboratory reports the viscosity values for quality control and formulation evaluation.

Common Challenges and Troubleshooting in ASTM D1823

Proper sample conditioning and consistent orifice conditions are essential to obtain ASTM D1823 results. Common problems include maintaining a constant test temperature, preventing air from being trapped in the samples, and keeping the calibrated orifice clean and clear. Viscosity results vary depending on sample preparation and conditioning. Laboratories ensure that they obtain reliable data by maintaining proper sample conditioning, regularly calibrating equipment, controlling the testing environment, and having trained technicians who conduct tests in a standard manner.

• The laboratory reports apparent viscosity in poises or pascal-seconds, based on the pressure exerted during extrusion, the geometry of the orifice, and the flow rate.
• The analyst records test conditions such as temperature, pressure, and orifice size.
• Laboratory records flow rate and extrusion time.
• The results show the flow characteristics of the plastisols at high shear rates that are used in processes.
• The higher the viscosity number, the more resistance the material exhibits to flowing; the lower the viscosity number, the easier the material flows.
• ASTM D1823 is used to test the viscosity of coatings, sealants, and vinyl products for quality control, formulation development, and process optimization.

Link to ASTM D1823