Hi, Big Thud;
I think the high molecular weight phthalate, DINP, is more of a recent development, but according to the owner of the UK-based PVC fetishwear and raincoat company, PVC-U-Like (PUL), DINP has (I quote) superior PVC-softening qualities. Because DINP is a phthalate with a higher molecular weight, it is considered to not have the supposed health risks associated with the low molecular weight phthalates.
I have copied-and-pasted some useful information from the Rainwear Central Forum:
Quote:
"The EU have what is called the REACH document. Contained in that document are over 250 chemicals which the EU have deemed potential health hazards and have restricted their use in manufactured products.
For many years from the 50's to the 80's a plasticiser called DEHP or DOP was used to soften PVC sheeting. It was very effective and cheap and did give PVC that soft rubbery feeling we love. Unfortuanetly DOP is listed on the REACH doc as having potential carcinogenic and endocrine potential so it was banned from Kids toys and placed on the REACH doc as a precaution. The fact is that the amount of DOP you would have to be exposed to to cause any effect is almost impossible to achieve and the body is very good at eliminating any DOP in your body through urine. In fact the majority of Blood bags made worldwide are still made using DEHP because of its superior plasticing qualities.
More recently there has been the development of DINP which is a
superior Plasticiser, but due to its high molecular weight has been demonstrated to be safe to Humans. At PUL we have been using DINP for many years now. However
in China there is
no restriction on DOP and because its
cheap its use is widespread and I'm afraid to say it but in China sometimes profit overides safety.
(Unquote).
So, Big Thud, referring to the last paragraph above (quote: "However in China there is no restriction on DOP and because its cheap its use is widespread and I'm afraid to say it but in China sometimes profit overides safety" unquote), it looks like you could potentially ask the China-based manufacturer to use DEHP or DOP in your Custom-Made inflatable. In all honesty, I'd happily come into contact with PVC rainwear or inflatables that have been softened with low molecular weight phthalates like DEHP or DOP. I believe the supposed health risks are exaggerated and taken out of perspective (what happens in a laboratory to the poor little rats/mice/Guinea pigs under the controlled and exacting scientific conditions does not neccessarily mean the same occurs in us humans in the real world).
Failing that, it looks like that DINP is a good alternative. The PVC products (raincoats, bedding, total enclosure inflatable body suit) I've purchased from PUL are all softened with DINP, and I am very pleased with their softness.