Page 312 - Engineering Plastics Handbook

272 Engineering Plastics

Powder grades Compounded grades
AI-10 4203L
AI-30 4301
AI-50 4275
4000T 4435
4000TF 5030
7130

Torlon powders
Torlon AI-10 polyamide-imide is roughly 50% imidized and has a molecu-
lar weight optimal for specialty coating formulations. It is utilized in an
extensive number of high-performance and high-temperature coatings
and adhesives. Many of these are electrical and wire coatings, corrosion-
resistant coatings, ablative coatings, nonstick cookware, and a variety of
other industrial coatings. The use in these markets is due to its high glass
transition temperature, adhesive strength, and thermal stability.
Depending on the polymer solids level, its relatively low molecular weight
provides a very usable solution viscosity and it may be dissolved in a
number of solvents.
With the aid of a tertiary amine, Torlon AI-30 becomes the water-
soluble analog of Torlon AI-10. The wet powder consists of 35% polymer
solids, 63% water, and 2% NMP. It is made water-soluble by forming an
ammonium salt with the amic acid groups on the polymer backbone.
Torlon AI-30 aqueous-based solutions are environmentally friendly and
allow the formulator to produce a high-performance coating or adhesive
without needing a dipolar aprotic solvent such as NMP.
Both Torlon AI-10 and Torlon AI-30 are synthesized by using MDA as
the primary diamine. Due to potential health consequences of exposure
to MDA, OSHA has strict regulations concerning its handling and mon-
itoring in the workplace. Because of their low molecular weights the
residual levels of MDA in Torlon AI-10 and Torlon AI-30 are just above
the OSHA threshold of 0.1 wt%, requiring these PAI powders to have
the same environmental and monitoring controls. Recently Solvay
Advanced Polymers, LLC, has introduced a new polyamide-imide
powder grade based on MDA and TMAC, but without the OSHA han-
dling and monitoring restrictions, due to its reduced residual MDA level.
It has the same performance attributes as Torlon AI-10 and similar
specifications.
Torlon AI-50 is another water-soluble polyamide-imide similar to
Torlon AI-30 in solids composition and coating performance. Because of
a slightly different polymer backbone, it also does not have the MDA
handling restrictions, plus it has a lower viscosity at the same solids level
compared to AI-30.