PVC Additives

There are a lot of great minds here, and I'm sure that someone with more recent experience than I, can trouble shoot your problems, but, your material supplier is the best source for information on fillers for their products.

If a product that you are molding with their resins fails to meet specification, that could be bad reflection on their material. Believe me, he wants you to be successful.

I do know that fillers bring their own set of problems with molding parameters, fill, burning (you may have to add vents to control this), surface finish and the list goes on and on..................

Good Luck

Thanks for replying. Unfortunately, the part molder is in China and it has been difficult to get meaningful dialog going on options for additives and to get clear & complete understanding of the likely outcome. The quality of the technical literature from the resin supplier is poor (close to non-existent). So, my strategy is to collect opinions & make a best choice from what I can learn from US sources.

A more pointed question, at the risk of looking at this too narrowly . . . Does anyone have successful experience in adding talc or other mineral filler (e.g. calcium carbonate) to PVC for the express purpose of stopping deformation in a pressure vessel? THANKS

Good luck! You will need it.

You may be just discovering the down side to long distance relationships.

If your molder in China is seeing a drop in business, like everyone else on the planet, he may become more responsive to you. Same with his material supplier.

I don't believe you will see too many US molders jumping in to help you solve problems for a Chinese molder.

The road to success is shortened by each failure

Chinese are good listerners when you mandate it. You use the Good ettiqates they fall behind.

Fiber glass stranding could be incorporated in a secondary layer on top of a primary seal layer but will increase number of operations and cost. This might keep your moulding to present dimensions, otherwise you are looking at a much thicker construction. Talc and other fillers will not help , your resin formulation must otherwise be strengthened to resist creep distortion . You must seek this information from chemical companys.

One good place to start is www.solvay-fluor.com who manufacture Hostalit brand rigid PVC resins. They have a huge amount of information on rigid PVC behaviour under steady tensile stress, under varying stress at different rates of change, fatigue behaviour, and more. The creep behaviour in tension at elevated temperatures is probably what you need to investigate. Rigid PVC is a very early polymer so there are decades of history recorded for such applications.

Again, Hostalit is a good keyword for your web searches and

www.solvay-fluor.com are good people to ask, perhaps guiding you to a specific grade of Hostalit, tailored to meet your design stresses, rates, temperatures.

Mark Bingham
Relativity PL