Coating for ski running surface of sintered ldpe and finer additive - giving high ratio of static to kinetic friction, useful for nordic ski

摘要

Coating for the running surface of skis, based on a sintered mixt. contg. LDPE with an average particle size of 100-500 microns, contains up to 5 wt.% of an additive (I) with an average particle size smaller than that of the LDPE by a factor of 10 to 10 power 4. (I) is present in the interstices between the LDPE granules and hence reduces the intergranular strength in comparison with unmodified LDPE. The LDPE is a high mol. or ultra-high mol. LDPE with an average mol.wt. of 0.5 x 10 power6 to 8 x 10 power 6. (I) is a plastics powder, pref. PTFE with a particle size of ca. 5 microns; or an inorg. powder, pref. SiO2 and/or Al2O3 with a particle size of 0.1-5 microns. The average particle size of (I) is a factor of max. 2000, pref. max. 1000 and min. 50, pref. min. 100 smaller than that of the LDPE. USE/ADVANTAGE -The coating increases the coefft. of static friction but hardly increases or even reduces the coefft. of kinetic friction, giving a very high static/kinetic friction ratio, as required for Nordic skis.