Materials | technology STYRENICS Tubing switches from PVC
Microspec has replaced PVC with Styrolution’s styrene butadiene block copolymers, in a range of flexible multi-lumen tubing.
The tubing makes it
possible to administer different medications from one access point. The new material offers better clarity than PVC, low drug absorption and unique processability, says Styrolution. Because lumens vary in
shape, number, symmetry, and diameter, Microspec needed a material that could create intricate tube structures. It chose Styroflex and Styrolux for several reasons: high processability enables the production of a more complex lumen structure – optional tube stabilisation was possible
MEDICAL
PPSU helps create tubing with variable flexibility
RiverTech Medical has developed medical tubing that has variable flexibility. The micro-tubing has two to three different stiffnesses and flexibilities along its length, and is aimed at catheter-based procedures such as angioplasty and stent placements. The tubing includes a layer of Radel
polyphenylsulfone (PPSU) resin from Solvay Specialty Polymers.
The tubing is made with RiverTech Medical’s
proprietary film cast technique which gives small-diameter, thin-walled parts with tight tolerances. The film cast process offers advantages over traditional extrusion by achieving inside diameters down to 0.004in (0.01016cm), outside diameter tolerances as
www.pipeandprofile.com
tight as ±0.0003in, and wall thicknesses as small as 0.0005in (0.00127cm). This tubing comprises multiple layers of
different polymers and a layer of woven wire material to provide reinforcement for the tubing wall. A fluoropolymer-based material is used for the inner tubing liner to produce a low-friction surface, and a softer thermoplas- tic is interspersed among the wire reinforce- ments for flexibility. Radel PPSU provides strength and stiffness as the 0.002in (0.00508cm) thick top layer. The medical-grade polymer delivers strength and melt processability that is comparable to materials like polyimide. ❙
www.solvayspecialtypolymers.com
by inserting guide wires or rigid tubes; a low yellowness index; higher clarity than PVC; increased run rates; and elimination of plasticiser migration. “Styrolution gave us the flexibility to create a more
complex, multi-lumen structure for our product and also to meet industry medical tubing requirements to replace PVC and eliminate plasticiser migration,” said Microspec’s Tim Steele. ❙
www.styrolution.com
TPEs
TPEs use styrenic chemistry
Teknor Apex has expanded its range of Sarlink thermoplas- tic elastomers (TPEs) for automotive applications, including two for extrusion. They are the first Sarlink
products to be based on styrenic TPE (TPE-S) chemistry. “Unlike the widely used
TPV automotive compounds, with which the Sarlink brand has been identified, the TPE-S compounds are not affected by variations in the price of EPDM rubber, a key ingredi- ent in TPV manufacture,” said Ger Vroomen, senior marketing manager for automotive at Teknor Apex. While standard TPVs are
restricted in colour to natural and black, TPE-S compounds are available in a variety of custom-matched colours. However, TPVs exhibit better resistance to hydrocarbon fluids such as oil and grease and have a higher service temperature than TPE-S compounds. The new high-performance
extrusion compounds, for functional parts such as sealing systems, have hardnesses ranging from 55 to 75 Shore A. At the same time, a range of general- purpose extrusion compounds is aimed at non-functional parts such as semi-rigid supporting components for sealing system backbones. Hardnesses range from 40 Shore A to 50 Shore D. ❙
www.teknorapex.com
March/April 2014 | PIPE & PROFILE EXTRUSION 47
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58