| 摘要 |
Curable (per)fluoropolyether polyurethanes obtained by reaction in a first step of a) (per)fluoropolyether diols having a number average molecular weight from 2,000 to 5,000; with b) diisocyanates of formula <?in-line-formulae description="In-line Formulae" end="lead"?>OCN-R-NCO (VIA)<?in-line-formulae description="In-line Formulae" end="tail"?> wherein R is a hydrogenated and/or fluorinated radical; in a second step with the compound c) saturated or unsaturated aliphatic hydrogenated diols, (alkyl)cycloaliphatic, aromatic; oligomers or polymers of butadiene with a number average molecular weight from 500 to 4,000 having end hydroxyl groups; provided that: when the diisocyanate b) is used and the radical R in formula (VIA) is: -Ph-CH<SUB>2</SUB>-Ph-, the hydrogenated diols c) are optional; when the radical R has a meaning different from that above mentioned, at least one of the used hydrogenated diols c) is selected from those belonging to the c<SUP>2</SUP>)-c<SUP>6</SUP>) groups; the sum of the equivalents of the compounds a) and c) being equal to the equivalents of the compound b).
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