K 2010 Trade press conference
June 22 and 23, 2010in Frankenthal, Germany
Re-inventing the color orange
New BASF pigment for high-performance plastics
Presentation byMario Dittes
TechnicalCenter Plastic Additives
BASF SE, Ludwigshafen,Germany
The color orange has a cheerful and refreshing, warm and dynamic effect. At the same time, this color tone sends a strong signal. When it comes to engineering plastics for use in demanding applications, however, useful orange pigments are few and far between. With its Sicopal® Orange K 2430, BASF is remedying this state of affairs. This new, extraordinarily stable inorganic mixed oxide is well-suited for areas of application in which many organic pigments fail, including those where high UVresistance and weathering resistance are required or where there is a need to withstand aggressive chemicals and high temperatures. But even aside from these high-end applications, this intensely colored, brilliant BASF pigment, with its very good covering capacity, can bridge existing gaps since this product expands the palette of warm, thermally stable orange shades into a new dimension.
Pigment selection can be difficult
Nowadays, anyone who would like to make a plastic product in an attractive color can choose from a broad spectrum of colorants. Especially organic pigments have proven to be exceptionally multi-faceted. BASF today is the industry leader in organic as well as inorganic pigments.
Nevertheless, there are areas where the search for the right colorant can be quite challenging for designers. Particularly in plastics processing technology, there is a demand for not only color intensity and brilliance but also for a number of other properties, one example being temperature resistance. For most organic pigments, the typical processing temperatures of some polymers (e.g. more than 300 degrees Celsius [572 degrees Fahrenheit] for polyamide) cause rapid degradation. At certain temperatures, even the inorganic alternatives undergo phase transformations that substantially affect the color impression. Such pigments are not suitable for use in plastics at high processing temperatures.
Intensely colored – heat-resistant – easy to process
These limitations are responsible for the fact that, for certain colors, there are by far not as many pigment choices as colorists would like. In spite of the strong psychological significance of this color shade, orange pigments are scarce when it comes to demanding areas of application. Many of the pigments currently available exhibit insufficient brilliance and low color intensity, which is why not all segments of the orange color spectrum are adequately covered.
Sicopal Orange K2430 sets new standards in numerous aspects. The pigment is suitable for use in a wide array of technically relevant plastics, ranging from polyolefins to PVC and PS all the way to ABS, PC, PET, PBT and PA. In particular, it is stable even at temperatures above 320 degrees Celsius [608 degrees Fahrenheit], and is thus resistant under the processing conditions of all known plastics. Moreover, it can replace often employed products containing cadmium and lead.
This pigment is also very attractive from the standpoint of processing technology: it is easy to disperse, that is to say, it can be distributed very evenly and quickly throughout the polymeric matrix. This is conducive to the production of films and fibers that are free of gel particles. Thin-walled molded parts such as housings and covers come out of the mold without displaying any warpage, in other words, with high dimensional stability. Furthermore, Sicopal Orange K2430 does not exhibit any tendency to migrate and has been approved in the European Union for food packaging and for use in toys; an application for FDA approval has been submitted.
Newly catalogued color shade
With the color it offers, Sicopal Orange K2430 has also bridged a gap that had existed until now. It is much redder than chromium titanates such as Sicotan® Yellow K2001 and Sicotan Yellow K2112 – two BASF pigments that had been employed up to now in the production of orange pigments for special applications. Other inorganic pigments are less favorable in terms of their coloration or else they lack sufficient depth of color. Sicopal Orange K2430 is one of the few new pigment developments of recent years to be given its own color index (C.I.) by the Society of Dyers and Colorists. It now bears the designation Pigment Orange 82 in technical circles.
This material can also add coloristic strength to pigment mixtures. Organic colorants such as, for example, Cromophthal® Orange GP or BASF’s Paliogen®Red K 3580 only acquire greater covering capacity and are more brilliant that conventional mixtures when combined with Sicopal Orange. It also entails advantages in combination with other inorganic pigments; for example, it serves to expand the color space of chromium titanates far into the orange range.
Pigment for outdoor applications
The outstanding UV-resistance and weathering resistance of this pigment accounts for constant and high levels of fastness, even at low concentrations and in mixtures with titanium oxide. Color-matching tests confirm that pigment formulations containing Sicopal Orange retain their defined color practically indefinitely when exposed to weathering. Comparable levels of fastness cannot be achieved through a combination with organic pigments.
This weathering resistance means that the pigment lends itself for co-extruded or laminated Luran® S films in outdoor applications. Even deep-dyed solid plastic objects such as garden tools or patio furniture, fence posts, playground equipment or car body parts all benefit from the excellent sturdiness of this new mixed oxide. Its migration behavior and good dispersability also make it a suitable candidate for dyeing self-adhesive films used outdoors.