After one year long research on this topic I can finally say that it works.
I've successfully bought small amount of one of the possible phthalate-free plasticizer for PVC Acetyl-tributyl-citrate (ATBC in abbreviation). It's an colorless and odorless oily liquid very stable in the condition of a room temperature. The difference is that unlike other oils ATBC doesn't harm flexible PVC but it soaks into and makes it softer.
It works in the condition of a room temperature which is the most important information ever.
How
it works:
Normally the
plasticizer is mixed with PVC pellets, heated into a liquid state,
mixed together and sprayed on a moving layer to make a plastic foil.
The plasticizer remains inside the material and makes it soft.
There
is about 30 to 50% of plasticizer inside the material.
The
plasticizer inside the material is in liquid state. It's like an oil.
It has melting point about -50°C and boiling point about 360°C. The
plasticizer can leach out of the material. It was the reason why
plasticizers based on phthalic acid
were banned in the year 2005. Those were replaced with new ones safe
to people. They're used in children's toys for example.
As
for my small experiments:
At
first I've tested methods how the plasticizer can be removed from the
material. It's easy.
I've
tested it on pieces of thin PVC foil. I just put it into a degreaser,
pure ethanol for example. After 2 hours the material lost its
softness and after 24 hours it was hard and brittle as a general rigid
plastic.
I've
almost lost the hope it would be possible to make it soft again.
After
half a year I was lucky to find one of few possible non-toxic
plasticizers. Acetyl-tributyl-citrate ATBC in abbreviation and I've
tested it on previously damaged material.
It
can simply soaks into the material and makes it soft again.
It
works in the condition of a room temperature which is the most
important information. It's the information you can't find anywhere.
Usually 24
hours after the application the material is soft and flexible again.
That's
how it works. It's right after the application.
The plasticizer is soaking into the green one. It's like a wave because the liquid started to soaks from the top layer firstly.
The
bigger one is pure ATBC, the smaller one is made by German collector of
inflatable toys allowing to I had been able to go this way. (Now you can use the Sculpey Clay Softener which is pure ATBC too)
Comparison: One
hard and brittle and the other soft and flexible
Another comparison
Comparison between original on the left hand side and soft pieces with
ATBC soaked inside. You can see those are more flexible than the original. It
means there is more plasticizer inside than in the original.
This
method is useful for restoration vintage stuff made of flexible PVC
which looses its flexibility and becoming brittle and easy to crack
over the years.
I'm
a collector of inflatable toys that's why I had to done this
research.
Using on a toy:
All tested pieces was stable for three months so I've decided to use ATBC on a toy.
Results:
It works. The main point is to apply the plasticizer from the inside of the toy. It prevents the damage of the paint as it soaks through it.
I've tested it on a toy which had been suffering from plasticizer loss because I've spent too much time in contact with the material last two years without knowing about that such thing like plasticizer loss might happen so quickly.
I've applied the plasticizer inside the toy through the valve into desired place when the toy was inflated. Right after that I've deflated the toy quickly using electric pump and then rubbed sides of the toy against each other to spread the liquid plasticizer inside over the desired place. I've then inflated the toy again and left it in the room. The plasticizer inside is like an oil so it holds in thin layer on the vinyl sides until it soaks.
It's important to avoid single drops inside the toy because they will make recognizable crater-like structure on the outside of the toy. But it's also fixable, just deflate the toy right after you realize such thing happened and try to spread remaining drops into wider area. After few days those craters will disappear as the plasticizer soaks wider into the material.
I've applied cca 0,5ml of plasticizer per square decimeter of 0,3mm thick vinyl.
troubles with the paint
two "rivers" of the plasticizer inside which successfully disappeared after few days
Now, after using cca 10ml of ATBC one of my favourite dragon toy is on the most places
soft again like originally was.
References:
