Materials testing is a vital component throughout the PVC industry. An understanding of the commonly used tests can help give you a competitive edge and ensure a quality end product.

1. FLEXIBLE PVC
TESTING FOR ANALYSIS AND QUALITY ASSURANCE

2. MATERIALS TESTING OVERVIEW
 Vital throughout the PVC Industry
 Ensures the PVC supplier that the compound performs as intended and will be
consistent across production runs.
 Designers base their selection of materials for new products on the results of
standard tests.
 Plastics manufacturers use test results to help establish process parameters
and quality control personnel use standard tests as a benchmark to be sure
products are meeting customers' requirements.
An understanding of the commonly used tests can help give you a
competitive edge and ensure a quality end product.

3. TESTING & EVALUATION METHODS
 The most commonly used tests for flexible pvc can be broken into the
following categories.
 Physical Property Testing
 Thermal Property Testing
 Electrical Property Testing
 Flammability Testing
 Rheology Testing
 Color Testing
 Accelerated Weathering Testing

4. TESTING AGENCIES
Several national and international agencies establish and publish testing
specifications for industrial materials.
 ASTM International
 International Organization for Standardization (ISO)

5. PHYSICAL PROPERTY TESTING
Physical property tests measure the molecular structure of the material which can often effect the
physical properties. The most important properties for measurement include:
 Specific Gravity (ASTM D792) - The ratio of the density of a liquid or solid mass to the density of
water at a specific temperature.
 Hardness (ASTM D2240) - The resistance of a plastic material to indentation. It is measured on a
Durometer machine which led to the industry to call hardness "Duro." Normal specification is
plus or minus 3 and three scales are used: Shore A for flexible, Shore C for semi rigid and Shore
D for rigid. Usually a delayed reading of 10 or 15 seconds is used.
 Tensile Strength (ASTM D638) - The maximum nominal stress sustained by a test specimen being
pulled from both ends, at a specific temperature and a specific rate of stretching. Specification is
a minimum amount in PSI.
 Elongation (ASTM D638) - The amount of increased length of a material until breakage.
Specification is a minimum percentage.
 Tear Strength (ASTM D1004) - The force required to tear a plastic material, usually expressed in
pounds per inch. Specification is a minimum number.

6. THERMAL PROPERTY TESTING
Thermal analysis provides material characteristics data in relation to temperature and time.
 Melt Temperature - The temperature required for the material to process.
 Maximum Continuous Operating Temperature (ASTM D794) - Accelerated tests essentially
used for the wire and cable industry to determine the resistance of the compound to
elevated use temperatures. The ratings are based on the maximum continuous operating
temperatures that wire insulation can withstand without degrading enough to fail in
service.
 Brittleness Temperature (ASTM D746) - The temperature at which 50% of the tested
specimens exhibit brittle failure at specified impact conditions. The lower the brittleness
point, the better the low temperature properties.

7. ELECTRICAL PROPERTY TESTING
Electrical tests, in general, are measurements of the resistance, conductivity or charge
storage either on the surface or throughout the PVC material.
 Volume Resistivity - (ASTM D257)- The resistance to leakage current through the body of
an insulating material.
 Surface Resistivity (ASTM D257)- The resistance to leakage current along the surface of
an insulating material.
 Insulation Resistivity (ASTM D257) - The resistance between two conductors of a circuit
or between a conductor and the ground when they are separated by an insulator.
Expressed in ohm-centimeters.
 Dielectric strength (ASTM D149)- The measurement of electrical voltage required to
break down or arc through a plastics material. The units are reported as volts per
millimeter of thickness.
 Dissipation (power) factor (ASTM D150) - The measure of the power (watts) lost in the
plastics insulator. Measurements are made at one million hertz.

8. RHEOLOGICAL TESTING
Rheology is the study of flow and deformation of materials under applied
forces. Put simply, it indicates how a material will process. A rheometer is
typically used for accurate measurement.
 Melt flow rate (ASTM D1238 or D3364) - The number one indication of
the materials viscosity in the melt phase. It is defined as the mass of
polymer in grams flowing per 10 minutes through a capillary of specific
diameter and length by a pressure applied via a range of standard
weights at specified temperature.

9. COLOR TESTING
Color's basic structure (visual light waves) can be measured with a
Spectrophotometer which assigns numerical values which act as names or
identities for specific colors.
This device uses three different sources of light including
 Daylight
 Incandescent light
 Flourescent light
The resulting set of color values is then compared to stored color standards.

10. FLAMMABILITY TESTING
Flammability, also called flame resistance measures the ability of a material to
support combustion.
 A term used with flammability testing is "self-extinguishing" which indicates the
material will not continue to burn once a flame has been removed.
 There are numerous flammability specifications that a material can meet. It is not
always convenient to conduct the actual flame test on every production run. There
is a test however called Oxygen Index that can be done to show the consistency of
lot to lot flammability properties.
 Oxygen Index (ASTM D2863) - The minimum concentration of oxygen in a flowing mixture
of oxygen and nitrogen that will just support flaming combustion of a plastic specimen.

11. ACCELERATED WEATHERING TESTING
Accelerated Weathering Testing is necessary to ensure that materials and products meet
their expected functionality and lifetime. An array of variables exist that ensure that the
effects of aging and weathering are hard to predict and as such can cause problems in the
future which may reflect back upon the product and your business in a negative way.
Weathering tests include the following:
 Ultraviolet Resistance (ASTM D4329, ASTM D 4587, ISO 4892) - Measures resistance to
the effects of direct sunlight or artificial weathering devices. UV radiation when
combined with water and other environmental factors may cause material degradation.
 Permeability (ASTM D1434) - The volume or mass of gas or vapor penetrating an area of
the material in 24 hours.
 Biochemical Resistance (ASTM G21) - PVC is inherently resistant to bacteria and fungi
but depending on the application, antimicrobial additives may be required.
 Chemical Resistance (ASTM D543) - Tests resistance to chemical reagents by simulating
performance in potential end use environments.

12. CONTACT US
Our experienced technical team can
perform these as well as other quality
assurance evaluations.
If you would like more information about
flexible PVC material testing methods,
please contact us at 800.462.4781 or
info@sylvin.com.