 |
| |
The new Styrolux® 3G 33 – not just for injection moulding |
Design – Aesthetics – Packaging
The new Styrolux® 3G 33 – not just for injection moulding
Presented by Dr. Daniel Wagner, Marketing Styrolux®
Trade Press Conference K 2004, June 22, 2004, Ludwigshafen, Germany
|
 |
For many years now Styrolux, a styrene/butadiene/styrene block copolymer (SBS) from BASF, has been used in a vast range of applications, enabling processors to manufacture optically appealing products with very good service properties. Thanks to a greater understanding of the relationships between polymer structure and properties, BASF’s researchers have now succeeded in achieving further properties improvements over conventional SBS grades in the form of Styrolux 3G 33.
Apart from their characteristic combination of transparency, brilliance and toughness, Styrolux grades share an ability to be processed easily and cheaply on all conventional extrusion, thermoforming and injection-moulding equipment. Good miscibility with general-purpose polystyrene means Styrolux can be used to produce rigid, transparent food and industrial packaging at a competitive price. In recent years Styrolux has also established a presence in the market for flexible, tough shrink wrap and labelling film. And thanks to its great clarity, excellent surface gloss and good melt rheology, Styrolux fulfils the prerequisites for producing complex mouldings with high optical appeal (figure 1).
|
|
The clearest Styrolux grade
Another third-generation addition to the Styrolux range is Styrolux 3G 33 – like the tough extrusion grade 3G 55 presented three years ago at K 2001. Styrolux 3G 33 is characterized by even better clarity and a very good combination of toughness and stiffness. Particularly worth noting is its excellent compatibility with general-purpose polystyrene (PS), which results in only a slight increase in haze.. In other words, Styrolux’s crystal clear transparency is largely retained in blends with PS (figure 2).
A comparison with Styrolux 656 C, a typical injection moulding grade, makes the advantages of 3G 33 obvious. Although the two grades have roughly similar stiffness, the new Styrolux 3G 33 is significantly more ductile and resistant to impact, and is visibly more transparent too.
The advantages for processors are obvious: On the one hand, blending with PS improves the moulding’s stiffness – and with it its heat distortion resistance – as well as enabling reduced material costs; on the other hand, no compromise has to be made as regards loss in transparency. Higher output is possible through faster moulding cycles thanks to good melt flow and easy demoulding. Styrolux 3G 33’s ductility also allows features such as integral hinges and snap-fits. With such a set of properties it really goes without saying that the new Styrolux grade is intended for injection moulding applications – in the segments: office equipment, toys and household, housing covers, as well as cosmetics packaging (figure 3).
|
|
Extruders also appreciate the improvements
The new product is positioned between the common injection products and the tougher extrusion grades. Viewed from both sides, the improved transparency of Styrolux 3G 33 makes it an attractive choice in other segments; indeed, the grade has also been proven in a number of extrusion applications (figure 4).
Thick thermoformable sheet extruded from Styrolux 3G 33 + PS blends, for example, is used for items for product present and display technology, where, apart from durability, crystal-clear appearance is paramount (figure 5).
However, in blends with PS, Styrolux 3G 33 does not achieve the same level of ductility as typical extrusion grades such Styrolux 648 D. This is clear from the plot of strain (or elongation) at break versus the blend’s PS content. Because of this, for extrusion applications, the PS content in blends with Styrolux is usually limited to less than 40 percent (figure 6).
BASF’s new third-generation Styrolux grade rounds off the company’s styrene block copolymer range, and have proved equally at home in both the injection-moulding and extrusion sectors. Thanks to its high clarity and toughness, there are certainly opportunities for Styrolux 3G 33 in competition with other transparent plastics – PET, PVC or the acrylics which occupy segments which until recently appeared barred to an SBS (figure 7).
|
|
|
|
|
|
