| 摘要 |
<p>#CMT# #/CMT# Primer comprises (wt.%): binder (15-40), additives (0.5-3), pigments, fillers and corrosion inhibitors (10-40), crosslinker (3-13) and solvent (30-55). #CMT# : #/CMT# An independent claim is also included for a metal substrate coated with an alloy, optionally an adhesion promoter, a primer as above and optionally a topcoat paint. #CMT#USE : #/CMT# The primer is useful for coating metal substrates, preferably in the building industry, especially facades, roofing boards, snow fences, trapezoidal profiles and metal coffers (claimed). #CMT#ADVANTAGE : #/CMT# The primer is flexible enough to cover cracks during deformation of zinc alloy coatings on steel. #CMT#METALLURGY : #/CMT# Preferred Alloy: This is a alloy of zinc and iron, aluminum, magnesium, chromium or nickel. #CMT#POLYMERS : #/CMT# Preferrred Primer: This comprises (wt.%): branched polyester (25-47.5), linear polyester (25-35), crosslinker (25-32.5) and auxiliary binder (2.5-5). The crosslinker is a blocked isocyanate, especially hexamethylene diisocyanate or isophorone diisocyanate. The additives are wetting agents, antifoams and catalysts, especially polycarboxylate esters (1-5%), silicone-free polymeric antifoam (0.1-1.5%) and acid catalyst (0.25-1.75%). The primer also includes 5-20 wt.% pigments, especially titanium dioxide and a calcium-modified silica anticorrosion pigment. Preferred Adhesion Promoter: This is a polycarboxylate ester, silicone, epoxy-functional phosphate ester or carboxy-functional polyester. #CMT#EXAMPLE : #/CMT# Typical primer comprises (wt.%): branched polyester (12.5), linear polyester (6.4), hexamethoxymethyl melamine (5.25), hexamethylene diisocyanate (1.875), Byk P104 wetting agent (0.25), Byk 055 antifoam (0.25), Nacure 1419 catalyst (0.75), pigments (29), butyl diglycol acetate (10) and Solvesso 150 ND (33.725).</p> |
