Polyurethane based adhesive for polarizing structure and polarized lens

Patent metadata

Field	Value
Publication number	US-2016108298-A1
Application number	US-201314778215-A
Country	US
Kind code	A1
Filing date	Mar 20, 2013
Priority date	Mar 20, 2013
Publication date	Apr 21, 2016
Grant date	—

Abstract

A polyurethane based adhesive containing one polyol compound derived from caprolactone monomer having a number average molecular weight between 200 and 1000 combined with a polyisocyanate compound. The functionality of the polycaprolactone polyol is between 1 and 4. Other aspects include a polarizing layered structure, a polarized lens and a method for manufacturing same all of which include the polyurethane based adhesive. The adhesive avoids delamination and is useful in optical applications where it will be in contact with water, for example during surfacing or edging process.

First claim

1 . A polyurethane based adhesive obtained by reacting at least one polyisocyanate compound with at least one polyol compound derived from caprolactone monomer having a number average molecular weight more than 200 and less than 1000.

2 . The Polyurethane based adhesive according to claim 1 , wherein the two components are mixed at a ratio NCO:QH in a range of 1:1-3:1 and preferably 3:1 and said caprolactone monomer has a number average molecular weight more than 200 and less than 300.

3 . The polyurethane based adhesive according to claim 1 , wherein the polyisocyanate compound is selected from an aliphatic diisocyanate such as hexamethylene diisocyanate.

4 . The polyurethane based adhesive according to claim 1 , wherein the functionality of the polycaprolactone polyol is more than 1 and less than 4, and preferably in a range between 2.3 and 2.5.

5 . A polarizing structure comprising:
a polarizing film; a protective film provided on at least one face of the polarizing film with an adhesive layer, wherein said adhesive layer is a layer of the polyurethane based adhesive of claim 1 .

6 . The Polarizing structure according to claim 5 , wherein two protective films are placed on each side of the polarizing film.

7 . The Polarizing structure according to claim 6 , wherein the polarizing film is a light-polarizing polyvinyl alcohol-based layer (PVA), and each of said protective films are independently selected from the group consisting of polycellulosics, polycarbonates, polyesters, poly(meth)acrylics, polycyclic olefin copolymers, polyolefinics, thermal plastic polyurethanes, polythiourethanes, polyvinyls, polystyrenes, polyamides, polyimides, polysulfones, polyether sulfones, poly ether ether ketones, polyphenylene sulfides, polyoxymethylenes, polyurethanes, epoxys or blend thereof.

8 . The polarizing structure according to claim 7 , wherein the polarizing film is a light-polarizing polyvinyl alcohol-based layer (PVA), and each of said, protective films are independently selected from the group consisting of triacetyl cellulose-base layers (TAC), polycarbonate layers (PC), polyethylene terephthalate) (PET), poly(methyl methacrylate) PMMA, polystyrene (PS), and cellulose acetate butyrate (CAB).

9 . A method for manufacturing a polarizing structure according to claim 5 comprising the following steps:
providing a polarizing film;
providing a protective film on at least one face of the polarizing;
deposing a layer of polyurethane based adhesive obtained by reacting at least one polyisocyanate compound with at least one polyol compound derived from caprolactone monomer having a number average molecular weight more than 200 and less than 1000 between said polarizing film and said protective film;
pressing the protective film against the polarizing film to form a polarizing structure; and
curing the assembly at a temperature between 40° C.-90° C. for about 16 hours.

10 . The method of claim 9 , wherein prior to said, deposing a layer of polyurethane based adhesive, the method further includes a step of surface treating of the protective film with at least a caustic treatment.

11 . The method of claim 9 , wherein said deposing a layer of polyurethane based adhesive comprises spin coating or roll coating the adhesive either onto one face of the polarizing film or one face of the protective film, or one face of the polarizing film and one face of the protective film.

12 . A polarized optical element comprising:
an optical base element; a polarizing structure; and. an adhesive structure placed between one surface of the optical base element and the polarizing structure so as to permanently retain said polarizing structure on the surface of the optical base element, wherein the polarizing structure comprises a polarizing film and a protective layer provided on at least one face of the polarizing film with a polyurethane based adhesive of claim 1 .

13 . The element according to claim 12 , wherein said adhesive structure includes a tri-layer adhesive structure which comprises a layer of hot melt adhesive layer sandwiched between two latex layers.

14 . The element according to claim 12 , wherein said adhesive structure includes a pressure sensitive adhesive.

15 . The element according to claim 12 , which further includes at least one functional coating placed on the protective film on the opposite side of said protective film from the polarizing film, said coating selected from the group consisting of hard coating, anti-reflective coating, photochromic coating, tinted coating, anti-fog coating and anti-smudge coating.

Assignees

• Essilor Int

Inventors

• Berzon Ronald A
• Jallouli Aref

Classifications

• B32B37/10

  characterised by the pressing technique, e.g. using action of vacuum or fluid pressure · CPC title

• C09J175/06 Primary

  from polyesters · CPC title

• B32B2551/00

  Optical elements · CPC title

• B32B27/306

  comprising vinyl acetate or vinyl alcohol (co)polymers · CPC title

• B32B2037/1215

  Hot-melt adhesive · CPC title