Anti-scratch additives

Suppliers have also been busy developing special anti-scratch additives, or new combinations of additives, which do not have these disadvantages this is because additives are potentially the lowest-cost approach for providing saatch resistance. [Note Some of these additives have proprietary compositions, but the section below will present useful details about their composition when possible) [17-2, 17-3, 17-6, 17-8]. 

Formulation developers have reported positive results from these tests when evaluating POs containing various additives or co-additives. These additive approaches could be seen as alternative to the approaches described above a few are summarized below  

Compounds with more finely micronized talc particles show less tendency to be visibly scratched than compounds with standard, coarser talcs. Talc particles can also be surface-treated to improve a compound s scratch resistance. Both of these factors can also improve the performance of anti-scratch additives [17-6]. 

Alternative slip agents optimized for common TPOs For example, compared with erucamide agents, Ciba s Irgasurf SR 100 reportedly improves scratch performance and impact resistance, when used optimally at about l%-3% loading in TPO compositions containing 20%-30% elastomer content and 10%-20% talc [17-5]. 

Advanced reactor polymerization processes Single-site metallocene catalyzed POs reportedly can produce PP with a fine, homogeneous dispersion of rubber regions and a soft, saatch-resistant surface. For example, LyondellBasell s Catalloy process and its Softell PP is said to provide improved saatch resistance and lower gloss, compared with standard TPO, and it can be compounded with glass fiber rather than talc [17-7]. 

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M. A. Frolov, I. V. Molyavko, A. I. Spivak, D. L. Rakhmankulov, V. R. Rakhmatullin, and N. A. Romanov. Lubricant for friction pairs working under heavy loads—contains mineral oil and additive in form of 2,4,8,10-tetra-oxaspiro-(5,5)-undecane, to improve anti-wear and anti-scratch properties. Patent SU 1817788-A, 1993. 

In plastics, the addition of talc improves their heat distortion temperature, dimensional stability, scratch resistance, impact resistance, and reduces the process cycle due to nucleation. Other important properties include high brightness, blocking of infrared in agricultural film, anti-blocking properties, and low absorption of packaged components. 

The first approaches proposed in the literature [54,55] consisted of the addition of alumina or silica particles to improve the mechanical properties of the silane coating. The addition of these particles increased the impact, scratch and wear resistance. The corrosion resistance of aluminium alloys also seemed to increase with controlled amounts of particles [54]. This effect was attributed to the formation of silicate species that delayed corrosion activity. Silane films containing silica and formed under applied potential also revealed improved anti-corrosion behaviour when applied to aluminium substrates. In this case, critical silica contents were proposed [55]. 

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