Polarizing structure comprising a glyoxal adhesive system and polarized lens comprising it
A polarizing structure comprising a polarizing film, a protective film provided on at least one face of the polarizing film with an adhesive layer which is a glyoxal-based adhesive or a water based polymer adhesive such as a PVOH-based adhesive layer, and wherein at least one face of said protective film oriented towards said polarizing film further comprises an adhesion primer structure. The adhesive avoids delamination of the polarizing structure, which withstands edging processing conditions, and which also show excellent dry peel force. Other aspects of the invention relates to a method for manufacturing such a polarizing structure, and a polarized ophthalmic lens comprising such polarizing structure.
1. A polarizing structure comprising:
a polarizing film having faces; and
a protective film provided on both faces of the polarizing film with an adhesive layer;
wherein the adhesive layer is a glyoxal-based adhesive obtained from a glyoxal water solution comprising:
about 5% by weight of glyoxal; and
about 5% by weight of polyvinyl alcohol (PVOH) polymer
at least one of the protective films comprises PC or PMMA; and
wherein a first face of the at least one protective film is oriented towards the polarizing film and further comprises an adhesion primer structure.
2. The polarizing structure of claim 1 , wherein the polarizing film is a light-polarizing polyvinyl alcohol-based layer (PVA), and the second protective film comprises at least one polycellulosic, polycarbonate, polyester, poly(meth)acrylic, polycyclic olefin copolymer, polyolefinic, thermal plastic polyurethane, polythiourethane, polyvinyl, polystyrene, polyamide, polyimide, polysulfone, polyether sulfone, poly ether ether ketone, polyphenylene sulfide, polyoxymethylene, polyurethane, and/or epoxy.
3. The polarizing structure of claim 1 , wherein the polarizing film is a light-polarizing polyvinyl alcohol-based layer (PVA), and the second protective film comprises one triacetyl cellulose-base layer (TAC), polycarbonate layer (PC), poly(ethylene terephthalate) (PET), poly(methyl methacrylate) PMMA, polystyrene (PS), polyamide (PA), and/or cellulose acetate butyrate (CAB).
4. The polarizing structure of claim 1 , wherein the adhesion primer structure is a mono- or multi-layered structure further defined as comprising a hot melt adhesive layer and/or a latex adhesive layer.
5. The polarizing structure of claim 1 , which comprises one protective film chosen from PC or PMMA, and one TAC protective film.
6. A method for manufacturing a polarizing structure of claim 1 , comprising the following steps:
providing a polarizing film;
providing a protective film on at least one face of the polarizing film;
deposing an adhesion primer structure on at least one face of the protective film oriented towards the polarizing film;
deposing a water based polymer adhesive solution, or a glyoxal-based adhesive solution between the polarizing film and the protective film;
pressing the protective film against the polarizing film to form a polarizing structure; and
curing the assembly at a temperature between 60° C.-100° C. for 5-30 min.
7. The method of claim 6 , wherein the water based polymer adhesive solution is a PVOH-based adhesive solution.
8. The method of claim 6 , wherein prior to deposing a water based polymer adhesive solution or a glyoxal-based adhesive solution, the method further includes a step of surface treating of the protective film with at least a caustic treatment or washing.
9. The method of claim 6 , wherein deposing a water based polymer adhesive solution or a glyoxal-based adhesive solution comprises rod coating or roll coating the adhesive layer 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.