Oligocarbonate polyols obtained from dianhydrohexitol dialkylcarbonate or a dimer of dianhydrohexitol carbonate, method for the production thereof and uses thereof

A process for the preparation of a polycarbonate-urethane, wherein an oligocarbonate polyol is reacted with a polyisocyanate, wherein the oligocarbonate polyol is obtained by a second process comprising the steps of:

• a stage (1) of introduction, into a reactor:
• of a monomer of formula (A1):
• in which R1 and R2 are identical or different alkyl groups, or of a dimer of formula (A2):
• in which R3 and R4 are identical or different alkyl groups, or of a mixture of (A1) and (A2);
• a stage (2) of introduction, into the reactor, of a diol monomer (B1) or of a triol monomer (B2) or of a mixture of (B1) and (B2), (B1) and (B2) both being different from (A1) and (A2);
• the molar ratio in the reactor of (A1) and (A2) with respect to (B1) and (B2) corresponding to the following formula:
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• a subsequent stage (3) of polycondensation by transesterification of the monomers and dimers (A1), (A2), (B1) and (B2) in order to obtain an oligocarbonate polyol having a molar mass of less than 5000 g/mol and two or more hydroxyl chain end groups, and
• a stage (4) of recovery of the oligocarbonate polyol;
• wherein the diol monomer (B1) is chosen from ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol or 1,10-decanediol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, 1,3-pentanediol, 1,4-hexanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol or 2-methyl-1,3-propanediol or from the following cyclic diols:
• cyclohexanedimethanols;
• tricyclodecanedimethanols;
• pentacyclopentanedimethanols;
• decalindimethanols;
• norbornanedimethanols;
• adamantanedimethanols,
• cyclohexanediols,
• tricyclodecanediols,
• pentacyclopentadecanediols,
• decalindiols,
• norbornanediols,
• adamantanediols,
• spiroglycol,
• 2,2,4,4-tetramethyl-1,3-cyclobutanediol;
• di-O-methylene-D-glucitol and dimethyl di-O-methylene-D-glucarate.