ASTM D5946

Introducing ASTM D5946 – Industrial Physics

ASTM D5946 is a global ASTM standard test method to inspect corona-treated polymer films using water contact angle measurements. 

If you need confidence that your polymer films will retain inks, coatings or adhesives, you’ll want to know all you can about the character of their surfaces. The good news is that the surface can be improved by one of several surface-treating techniques.  

Plastic corona treatment is a surface modification technique that uses a low temperature corona discharge plasma to impart changes to the properties of the surface. This has been found to increase the wetting tension of a polymer film.  

This ASTM D5946 test method covers measurement of the contact angle of water droplets on corona-treated polymer film surfaces. You can achieve highly accurate results following this ASTM approach and using a trusty goniometer from Industrial Physics.

The stronger the corona treatment, the more actively the surface will react with various polar interfaces. If you follow the ASTM D5946 test method closely, it’s possible to relate the contact angle of a polymer film surface to its ability to accept and retain inks, coatings and adhesives.  

The wetting tension of a polymer film belongs to a group of physical parameters for which no standard of accuracy exists. The wetting tension of a polymer cannot be measured directly because solids do not change shape measurably in reaction to surface energy.  

Although the level of surface treatment of polymer films has been traditionally defined by industry in terms of dynes/cm (mN/m), these values are derived from a subjective interpretation of the observed test liquid behavior. 

ASTM D5946 water contact angle measurements

Within ASTM D5946 the following ranges of water contact angle values are listed. These can be used as a guide for defining the level of surface treatment of polyolefins and many other polymer films: 

• Marginal or no treatment (>90°) 
• Low treatment (85 to 90°) 
• Medium treatment (78 to 84°) 
• High treatment (71 to 77°) 
• Very high treatment (<71°). 

ASTM D5946 testing equipment

So, how can Industrial Physics improve your ASTM D5946 testing?  

TQC Sheen Fibro PGX+ Pocket Goniometer 

Our innovative pocket goniometer checks surface properties for contamination, adhesion and the printability of metals, polymers, glass, paper, board…and much more! 

This pocket goniometer defines several surface properties for quality control. It uses a camera which can take up to 80 pictures per second. The technology allows it to measure both the static and the dynamic contact angle of the droplet.  

Our goniometer provides a mini test environment and can be placed directly onto the sample surface. It can even be used to measure surface tension and surface free energy. 

TQC Sheen PGX Dosing Unit PG1010 

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We’ve been making inks and coatings testing equipment for many years. We like to share our knowledge and experience with our customers and the wider industry.

Across the knowledgebase section of our website, you’ll find blogs that explore all manner of paint testing subjects. To start off, why not have a look at this article that demonstrates how to perform a viscosity test? Then maybe read this one that investigates the impact of additives in paint and coatings. 

If you have any questions about ASTM D5946 and how we can help you with any aspect of your paint testing, then just get in touch!  

Your global test and measurement partner for ASTM D5946