Is There Such a Thing as PVC-Free Plastisol?

Manufacturer: Some of our products are made from PVC plastisol including household gloves. Our customers are now requesting us to switch to non-PVC plastisol. Is there such a thing and what are the main concerns over PVC?

John Woon (Senior Latex Consultant): We have all heard about many markets moving away from all things made from PVC for the following reasons:

1) Generation of chlorine during processing and aging sometimes in the form of HCl which not only corrodes the equipment but is also a health hazard. (The Japanese car companies like Toyota, Nissan and Honda have eliminated PVC in their car interiors since 2007)

2) Carcinogenicity of residual monomer i.e. vinyl chloride.

3) Emission of Dioxins when PVC is burnt or incinerated. Dioxins which are a group of polyhalogenated compounds are considered as toxic environmental pollutants that are health hazards.

4) There is of course the issue with phthalate plasticizers but this is a different problem which I've dealt with earlier in this "Forum".

But is there a possibility of making plastisols without using PVC? The answer is “Yes”. PVC could in fact be replaced with a “core-shell” structured acrylics resin (also in powder form). The price of this acrylic powder could be more expensive but  it can be gelled in shorter time and at lower temperatures than PVC (i.e. less than 120C vs 140C) meaning it would save energy cost for the users.

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The list of potential suppliers have been sent to you separately.

Freeze-Thaw Stability of Latex Compounds

Manufacturer: We are manufacturing synthetic latex based coating compounds for EU markets. Recently we have had complaints about the Freeze-Thaw stability of our products. Can you please suggest a good but easy method to measure this? Would appreciate if you could advise us on how to improve freeze-thaw stability.

John Woon (Senior Latex Consultant): You can use the following method:

1) Fill up a glass bottle (of capacity of about 250 gram) with the latex compound to three-quarter full.
2) Subject the bottle to 10 cycles of 18 hours freezing at - 20°C followed by 6 hours thawing at room temperature.
3) Examine the sample for signs of gelling and precipitation (coagulation).

If the test confirms that the compound has poor resistance to freeze/thaw, proceed to do the following:

1) Add ethylene glycol at 1 to 2% into a fresh sample of the latex compound and stir gently for 1 hour.
2) Repeat the freeze-thaw test.

If ethylene glycol cannot work, please let me know and I would suggest other alternatives.