Stanyl®, a high-heat polyamide 4,6 (PA46) resin from DSM Engineering
Plastics, is adding a new market segment, fibre and film, to its existing
broad portfolio of injection moulded, high-tech and high-heat engineered
applications. As with injection moulded designs, Stanyl-based fibre and film
benefit from the material’s unusually high crystallinity and resulting
extraordinary mechanical properties, as well as its high melting point. In
fibre and film, Stanyl adds a new side: it can be soft and supple.
“Stanyl brings new potential for designers by offering a family of materials
that offers high performance, high temperature resistance and high wear and
abrasion resistance,” said Dan Bishop, Stanyl global marketing manager. “It
provides mechanical properties beyond those of such standard engineering
materials as PA 6 and PA66. And it does so at lower cost than more exotic
materials, such as PPS, PEEK, aramid and fluorinated polymers.”
Processing of Stanyl into filament or sheet can be accomplished with standard
equipment running at temperatures slightly higher than conventional materials.
Because Stanyl does not cross-link under heat, the material presents
processing advantages as well. It does not gel or build up in equipment
internals, even when subjected to long dwell times in mixers, injection screws
and extrusion dies. In fact, the viscosity of Stanyl becomes lower with heat
ageing, making it in effect self-cleaning, avoiding the periodic line stoppage
and tear-down required to clean out gels formed by other PA types.
Fibre applications include staple for felted products – its affinity to water
makes it ideal for papermaking blankets – as well as industrial yarns for
airbag seam thread, abrasion-resistant garments and protective composite
fabrications.
Filament uses include such diverse applications as professional hairbrushes,
and as rubber reinforcement for v-belts, automotive hose and tire tread and
carcass uses. It has shown excellent performance as automotive air-bag thread,
a highly demanding application. During inflation of the airbag, seams are
severely stressed by the explosion. The stitch holes in the seam open, and the
hot inflation gasses flow out, causing intensive short-term heating of the
sewing thread.
A high tenacity multifilament yarn has been commercially available since 1996
from Polyamide High Performance GmbH (Wuppertal, Germany) under the trade name
Stanylenka™ yarn
Film applications include a range of high-heat products, from gaskets to
stamped bearing surfaces, to dielectric and solderable sheet for electronics,
all of which take advantage of the material’s heat or abrasion resistance.
Stanyl film additionally provides an excellent barrier to chemical permeation.
“The high crystallinity of Stanyl provides high performance for all properties
that correlate with crystallinity,” said Jippe van Ruiten, global research &
technology application development technical service manager, Stanyl Fibre &
Film. “This includes abrasion resistance, friction, modulus, creep, resilience
and resistance to hydrolysis.”
Stanyl’s high amide content gives the material a higher affinity for moisture
than other PAs. Overall there is a balance between a higher tendency to pick
up moisture and a lower volume of the amorphous phase due to higher
crystallinity. In textile applications this results in significant enhancement
of tactile properties and moisture management. It also permits streak-free
dyeing and decoration with intense colours.
