Polyurethane urea-containing compositions and optical articles and methods for preparing them
A composition for the preparation of a transparent, non-elastomeric optical article is provided, the composition including: (1) a polyisocyanate component containing one or more different polyisocyanates; and (2) a component that is reactive with isocyanates, including: (a) optionally at least one polyol having a number average molecular weight greater than 500; (b) (i) at least one polyol and/or polythiol and (ii) at least one compound containing both amine and hydroxyl functional groups, wherein the compound (ii) has a number average molecular weight less than 500; and optionally (3) a urethanation catalyst. Multi-step and one-pot methods of preparing a cured, non-elastomeric polyurethane-containing optical article are also provided.
1. A method of preparing a transparent, non-elastomeric optical article comprising:
(1) combining to form a reaction mixture:
(a) a polyisocyanate component comprising one or more different polyisocyanates; and
(b) an active hydrogen component comprising:
(b1) a first component that is free of amino groups comprising at least one first polyol; and
(b2) a second component comprising,
at least one second polyol and/or at least one polythiol, and
at least one compound containing both amine and hydroxyl functional groups and has the structure H 2 N-L-OH, wherein L is a linear or branched alkyl, aryl, aralkyl, or alkaryl chain optionally containing hetero atoms,
wherein the at least one second polyol has a number average molecular weight of 60 to 450;
(2) introducing the reaction mixture to a mold at a temperature and for a time sufficient to form a thermoset polymerizate; and
(3) releasing the polymerizate from the mold to yield a transparent optical article.
2. The method of claim 1 , wherein less than 40 percent by weight of the first polyols, based on total weight of first polyols in the first component (b1), have a number average molecular weight greater than 450.
3. The method of claim 2 , wherein less than 35 percent by weight of the first polyols, based on total weight of first polyols in the first component (b1), have a number average molecular weight greater than 450.
4. The method of claim 3 , wherein less than 30 percent by weight of the first polyols, based on total weight of first polyols in the first component (b1), have a number average molecular weight greater than 450.
5. The method of claim 1 wherein the polyisocyanate component comprises isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, diphenylmethane-4,4′-diisocyanate, meta-tetramethylxylene diisocyanate (1,3-bis(1-isocyanato-1-methylethyl)-benzene), and/or meta-xylylene diisocyanate.
6. The method of claim 1 wherein the compound containing both amine and hydroxyl functional groups has a number average molecular weight of 60 to 450.
7. The method of claim 1 wherein the compound containing both amine and hydroxyl functional groups has the structure:
wherein R is H or a C 1 to C 4 alkyl group and n is an integer from 1 to 10.
8. The method of claim 1 wherein the compound containing both amine and hydroxyl functional groups comprises ethanolamine, amino-2-propanol, 2-amino-1-methyl-1-propanol, 2-amino-1-butanol and/or diethylene glycolamine.
9. The method of claim 1 wherein the reaction mixture is free of polyamines.
10. The method of claim 1 wherein the reaction mixture is free of compounds containing both amino and aromatic functional groups.
11. The method of claim 1 wherein the reaction mixture is free of polyols containing aromatic groups.
12. The method of claim 1 wherein (b2), of the active hydrogen component (b), comprises at least one polythiol.
13. The method of claim 1 wherein the transparent optical article demonstrates a refractive index of at least 1.52.
14. A method of preparing a transparent, non-elastomeric optical article comprising:
(1) combining to form a reaction mixture:
(a) a polyisocyanate component comprising one or more different polyisocyanates; and
(b) at least one first polyol, wherein the polyisocyanate component is present in stoichiometric excess relative to hydroxyl functional groups;
(2) allowing the components to react at a temperature and for a time sufficient to consume all of the hydroxyl functional groups and form an intermediate product comprising a polyurethane prepolymer having isocyanate functional groups in admixture with excess polyisocyanate;
(3) mixing the intermediate product formed in step (2) with
at least one compound containing both amine and hydroxyl functional groups, wherein the compound containing both amine and hydroxyl functional groups has the structure H 2 N-L-OH, wherein L is a linear or branched alkyl, aryl, aralkyl, or alkaryl chain optionally containing hetero atoms, and
optionally an active hydrogen component comprising at least one second polyol and/or at least one polythiol,
to form a second reaction mixture;
(4) introducing the second reaction mixture formed in step (3) via injection to a mold at a temperature and for a time sufficient to form a thermoset polymerizate; and
(5) releasing the polymerizate from the mold to yield a transparent optical article.