Lightfast polyurethane compositions

Patent metadata

Field	Value
Publication number	US-9718916-B2
Application number	US-201615008504-A
Country	US
Kind code	B2
Filing date	Jan 28, 2016
Priority date	Apr 23, 2012
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

The present invention relates to a composition comprising 10 to 50 wt.-% of at least one polyisocyanate a-1) based on hexamethylene diisocyanate, comprising at least one oligomeric polyisocyanate based on hexamethylene diisocyanate and optionally monomeric hexamethylene diisocyanate and 50 to 90 wt.-% of at least one polyisocyanate a-2) based on isophorone diisocyanate, comprising at least one oligomeric polyisocyanate based on isophorone diisocyanate and optionally monomeric isophorone diisocyanate, with the proviso that at least one of the components a-1) and a-2) additionally comprises monomeric isocyanate of the named kind, as well as at least one sulfur-containing component. It has been shown that the above mentioned mixture of the specific isocyanate group containing components improves the thermal and mechanical properties of a cured composition. Thus prepared molded articles are particularly suitable for the preparation of spectacle lenses, inter alia due to these properties.

First claim

The invention claimed is:

1. A method for preparing an optical lens, the method comprising
providing a composition, comprising
component A)
10 to 30 wt.-% of at least one polyisocyanate a-1) based on hexamethylene diisocyanate, comprising at least one oligomeric polyisocyante based on hexamethylene diisocyanate and optionally monomeric hexamethylene diisocyanate, and
70 to 90 wt.-% of at least one polyisocyanate a-2) based on isophorone diisocyanate, comprising at least one oligomeric polyisocyanate based on isophorone diisocyanate and optionally monomeric isophorone diisocyanate, and the amount of isocyanate groups of component A) is in a range from 25 to 34 wt-%, based on the total weight of component A),
with the proviso that,

the polyisocyanate a-1) comprises monomeric hexamethylene diisocyanate, or the polyisocyanate a-2) comprises monomeric isophorone diisocyanate, or
the polyisocyanate a-1) comprises monomeric hexamethylene diisocyanate and
the polyisocyanate a-2) comprises monomeric isophorone diisocyanate,
wherein the %-data relate to the sum of components a-1) and a-2),

component B)
at least one sulfur-containing component; and optionally

component C)
one or more auxiliaries and/or additives;

pouring the composition into a mold; and
allowing the poured composition of isocyanate groups of component A) with the isocyanate-reactive groups of component B), and optionally component C to cure, and thereby, form the optical lens.

2. The method according to claim 1 , wherein the optical lens is a spectacle lens.

3. The method according to claim 1 , wherein the sulfur-containing component is selected from the group consisting of polythiols, sulfur containing hydroxy compounds, and mixtures thereof.

4. The method according to claim 1 , wherein the sulfur-containing component has a molecular weight of 78 to 1000 g/mol.

5. The method according to claim 1 , wherein the at least one auxiliary and/or additive is selected from the group consisting of UV-stabilizers, catalysts, antioxidants, mold release agents, dyes, and mixtures thereof.

6. The method according to claim 1 , wherein the at least one oligomeric polyisocyanate of a-1) is obtained by reacting only hexamethylene diisocyanate as diisocyanate unit, and the at least one oligomeric polyisocyanate of a-2) is obtained by reacting only isophorone diisocyanate as diisocyanate unit.

7. The method according to claim 1 , wherein the at least one sulfur-containing component is selected from the group consisting of polythiols, sulfur containing hydroxy compounds, and mixtures thereof, and has a molecular weight of 140 to 800 g/mol.

8. The method according to claim 7 , wherein the sulfur-containing component has at least two thiol-groups per molecule.

9. The method according to claim 1 , wherein the component A) has a viscosity of 100 to 3000 mPas at 23° C.

10. The method according to claim 1 , wherein the amount of isocyanate groups of component A) is in a range from 26 to 30 wt-%.

11. The method according to claim 7 , wherein the amount of isocyanate groups of component A) is in a range from 26 to 30 wt-%.

12. The method according to claim 1 , wherein the pouring of the composition includes pouring into a non-heated mold at room temperature.

13. The method according to claim 1 , wherein the optical lens has a thickness of at least 1 mm.

14. A method for preparing an optical lens, the method comprising:
providing a composition comprising a component A), and a component B), wherein component A) comprises
10 to 30 wt.-% of at least one polyisocyanate a-1) based on hexamethylene diisocyanate, and comprising at least one oligomeric polyisocyante that is obtained by reacting only hexamethylene diisocyanate as diisocyanate unit, and 90 to 70 wt.-% of at least one polyisocyanate a-2) based on isophorone diisocyanate, and comprising at least one oligomeric polyisocyanate that is obtained by reacting only isophorone diisocyanate as diisocyanate unit, wherein the %-data are based on the sum of components a-1) and a-2), and the amount of isocyanate groups of component A) is in a range from 25 to 34 wt-%, based on the total weight of component A),
with the proviso that the polyisocyanate a-1) comprises monomeric hexamethylene diisocyanate, or the polyisocyanate a-2) comprises monomeric isophorone diisocyanate, or the polyisocyanate a-1) comprises monomeric hexamethylene diisocyanate and the polyisocyanate a-2) comprises monomeric isophorone diisocyanate, and

component B) comprises one sulfur-containing component selected from the group consisting of polythiols, sulfur containing hydroxy compounds, and mixtures thereof, and the sulfur-containing component has a molecular weight of 78 to 1000 g/mol;
pouring the composition into a mold; and
allowing the poured composition of isocyanate groups of component A) with the isocyanate-reactive groups of component B), and optionally component C to cure, and thereby, form the optical lens with a refractive index in a range of 1.541 to 1.587.

15. The method according to claim 14 , wherein the at least one sulfur-containing component has a molecular weight of 140 to 800 g/mol, and at least two thiol groups.

16. The method according to claim 14 , wherein the optical lens has a low optical dispersion characterized by high Abbe-numbers of from 40 to 49.

17. The method according to claim 14 , wherein the amount of isocyanate groups of component A) is in a range from 26 to 30 wt-%.

18. The method according to claim 1 , wherein the optical lens has a refractive index in a range of 1.541 to 1.587, and a low optical dispersion characterized by high Abbe-numbers of from 40 to 49.

Assignees

• Covestro Deutschland Ag

Inventors

• Greszta-Franz Dorota
• Krause Jens
• Laas Hans-Josef

Classifications

• C08G18/73

  acyclic · CPC title

• G02B1/04

  made of organic materials, e.g. plastics (G02B1/08 takes precedence) · CPC title

• C08L75/04

  Polyurethanes · CPC title

• C08G18/792

  formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates · CPC title

• C08G18/7887

  having two nitrogen atoms in the ring · CPC title