Blocked isocyanate diols and preparation thereof
AssigneeNational Starch and Chemical Corporation
InventorsHenry Stanley, Dilip K. Ray-Chaudhuri
Life of this patent
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Abstract
Copolymerizable blocked isocyanate diols are prepared by reacting a blocking agent with an isocyanate group of an organic diisocyanate under controlled conditions, thereby forming a blocked isocyanate group, and reacting the second isocyanate group in a subsequent step with the amine portion of a selected amine diol under anhydrous conditions. The resultant products are used to prepare self-crosslinkable, linear polyurethanes of high molecular weight.
Claims7
A blocked isocyanate diol consisting of an organic diisocyanate containing one isocyanate group which has been reacted with a blocking agent containing a hydroxyl group, and a second isocyanate group which has been reacted with the amine portion of an amine diol of one of the general formulae:
- NH(DOH).sub.2 or NHRD'(OH).sub.2
- wherein
- D is an alkylene (C.sub.2 -C.sub.20) or aralkylene (C.sub.7 -C.sub.20) radical in which the hydroxyl group is attached to an aliphatic carbon atom,
- D' is an alkylene (C.sub.2 -C.sub.20) or aralkylene (C.sub.8 -C.sub.20) radical in which each of the hydroxyl groups is attached to a different aliphatic carbon atom, and
- R is hydrogen or an unsubstituted or substituted alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, alkaryl, or aralkyl radical which is not reactive with active hydrogen atoms or isocyanate groups.
A process for preparing a blocked isocyanate diol comprising the steps of:
- a. reacting a blocking agent which contains a hydroxyl group with an organic diisocyanate at a temperature of 25.degree.-100.degree. C. for 1-8 hours for aromatic diisocyanates and at 50.degree.-120.degree. C. for 3-10 hours for aliphatic diisocyanates, wherein the ratio of blocking agent to diisocyanate is from 0.8:1.0 to 1.2:1.0, to obtain a blocked adduct;
- b. reacting the blocked adduct with an amine diol of one of the general formulae:
- NH(DOH).sub.2 or NHRD'(OH).sub.2
- wherein
- D is an alkylene (C.sub.2 -C.sub.20) or aralkylene (C.sub.7 -C.sub.20) radical in which the hydroxyl group is attached to an aliphatic carbon atom,
- D' is an alkylene (C.sub.2 -C.sub.20) or aralkylene (C.sub.8 -C.sub.20) radical in which each of the hydroxyl groups is attached to a different aliphatic carbon atom, and
- R is hydrogen or an unsubstituted or substituted alkyl, alkenyl, cycloalkyl, cycloalkenyl aryl, alkaryl, or aralkyl radical which is not reactive with active hydrogen atoms or isocyanate groups,
- wherein the ratio of blocked adduct to amine diol is from 0.8:1.0 to 1.1:1.0, said reaction being carried out at a temperature of 0.degree.-100.degree. C. for 1-8 hours under anhydrous conditions;
- and
- c. isolating the resultant product.
Dependencies are inferred from the claim text.