TAPPI T458

Introducing TAPPI T 458 - Industrial Physics

TAPPI T 458 is a global TAPPI standard method that’s used to measure the contact angle between air and liquid on a paper surface. This is taken as a measure of the resistance of the paper surface to wetting by the liquid.

So why are tests like the TAPPI T 458 method important? Essentially, it's because it helps you to understand the characteristics and quality of paper types.

Understanding the ruling and writing qualities of paper are particularly important for drafting and writing. These papers must accept ink (ruling quality) without feathering (writing quality). In order to measure these, knowing certain ranges of contact angle will help.

The initial angle of contact - known as the wettability - gives you a measure of the ruling quality of the paper. Whereas the rate of change in the wettability is considered to be a measure of the writing quality.

A wettability test can also be helpful for people who seek to understand the quality of a paper - for example when testing adhesives. However, you’d have to modify the TAPPI T 458 approach considerably to achieve this and therefore the procedure is restricted to ruling and writing purposes.

The TAPPI T 458 testing process

First a small drop of liquid is placed on the paper surface. Next you magnify and measure the contact angle of the drop. These measurements are taken both on contact and then after a minute.

You can use a range of methods to magnify and measure the contact angle. These include projection, photography, and microscopic goniometry. All you need to ensure is that the contact angle can be accurately determined to the nearest degree. A goniometer from Industrial Physics is the ideal solution!

TAPPI T 458 testing devices

So, how can Industrial Physics improve your TAPPI T 458 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.

Your global test and inspection partner for TAPPI T 458