Surface protecting film for painted surfaces, comprising polyurethane-based pressure-sensitive composition
View Patent ↗A self-adhesive surface protective film, particularly for automobile paint surfaces, having a backing layer and a self-adhesive layer based on a crosslinked polyurethane, characterized in that the loss angle tan δ of the polyurethane at room temperature in the frequency interval from 10 −1 to 10 2 rad/sec rises or remains at the same level.
1. A method of protecting a painted surface of an automobile or an automobile part from damage during assembly or transit, said method comprising applying to said painted surface a self-adhesive protective film comprising a backing layer and a self-adhesive layer comprising a crosslinked polyurethane, wherein the loss angle tan δ of the polyurethane at room temperature in the frequency interval from 10 −1 to 10 2 rad/sec rises or remains at the same level.
2. The method according to claim 1 , wherein the backing layer comprises a thermoplastic polyolefin sheet which is unoriented.
3. The method according to claim 1 , wherein the backing layer comprises at least one polyolefin from the group of the polyethylenes and/or the group of the polypropylenes.
4. The method according to claim 1 , wherein the backing layer comprises at least one light stabilizer and/or one UV stabilizer.
5. The method according to claim 1 , wherein the UV permeability of the surface protective film in the wavelength range from 290 to 360 nm is less than 1%.
6. The method according to claim 1 , wherein the thickness of the backing layer is between 20 and 80 μm.
7. The method according to claim 1 , wherein aliphatic isocyanates are used in forming the polyurethane of the self-adhesive composition.
8. The method according to claim 1 , wherein the polyurethane of the self-adhesive composition is formed using as polyol component polypropylene glycols, polyethylene glycols, hydrogenated hydroxyl-functionalized polyisoprenes, hydroxyl-functionalized polyisobutylenes or hydroxyl-functionalized polyolefins.
9. The method according to claim 1 , wherein fillers, pigments, rheological additives, additives for improving the adhesion, plasticizers, resins (tackifiers), elastomers, aging inhibitors (antioxidants), light stabilizers, UV absorbers, and/or other auxiliaries and additives are added to the self-adhesive composition.
10. The method according to claim 4 , wherein the backing layer comprises the at least one light stabilizer and/or one UV stabilizer in an amount of at least 0.15% by weight.
11. The method according to claim 4 , which comprises an adhesion promoter layer arranged between the backing layer and the adhesive layer.