Pitch-Polyurethane Coatings

Like pitch-epoxy coatings, pitch-polyurethane coatings are excellent materials for use under very corrosive conditions such as for sewage work, marine and port installations, chemical works and power stations. Particular applications are for ... 

Pitch-polyurethane coatings are two-component materials containing polyol as the base resin and an isocyanate curing agent. They cure satisfactorily at temperatures as low as 0°C (BSC, undated). 

Pitch-polyurethane coatings should not be used without obtaining specific recommendations from the manufacturer for the particular apph-cation being considered. 

Crystic Kollerdur. [Scott Bader] One-pack polyurethane resins for primers, sealers, coatings, or formulatimis such as aggregate-filled floors, pitch-ex-tend roofing systems. 

Coal tar pitches are less readily available than they used to be their content of polynuclear aromatic hydrocarbons makes their safe use suspect. They have been replaced to some extent by the less effective petroleum bitumens whose mechanical properties are improved by combination with poly(vinyl chloride) and other chlorinated polymers as one-pack, nonconvertible coatings, or by combination with epoxy or polyurethanes in high-performance two-pack convertible coatings. Similar materials are preferred for coating ballast spaces and double bottoms in vessels, where economical systems are required that do not have to be attended throughout the lifetime of the vessel (15-25 years). Multiple coats with a total thickness of 250-400 pm are usually employed. 

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