What is Hand?
Leigh Ann Green
Director, Technical
Mississippi Polymers, Inc.
April 7, 2017
As with every other industry, the vinyl (PVC) film industry has its own “language”. Many of the terms we use and assume are common knowledge are, in fact, sources of confusion for those with a different background. One such term is hand. What exactly is hand, and how is it measured?
Let’s start with what hand is not:
- Hand is not Handle. Handle is a quantitative measure of the combined effects of a film’s surface friction and flexibility and requires the use of a handle-o-meter.
- Hand is not Shore Hardness. Shore Hardness is measured quantitatively using a gauge (much like a tire gauge).
- Hand is not PHR (parts per hundred of resin). PHR is the amount of plasticizer in a film per one hundred parts of resin. However, the PHR of a film will directly correlate with the hand (see more below).
Hand refers to a subjective, relative property of vinyl film and cannot be described quantitatively.
- Hand is subjective. It is measured solely by feeling a sample of the film through crushing it, “wadding” it up, pushing on it with the fingers.
- Hand is relative. A “soft hand” film at a facility where mostly rigid films are produced could be deemed to have a “firm hand” at a flexible film facility.
**Note – as mentioned above, PHR has a direct correlation to hand.
- The higher the PHR of plasticizer in a film, the softer the film.
- The type of plasticizer will also affect hand. Not all plasticizers “plasticize” equally.
What are the advantages of measuring hand?
- Hand is a quick, qualitative test used in the manufacturing and converting process.
- For those with experience, film does not necessarily have to normalize before testing the hand. But, experience is important and it does matter to the result.
- No special equipment is needed to measure hand – only hands!