Process for applying a coating onto a surface of a lens substrate

Abstract

The present invention provides a method for applying a coated or uncoated film onto at least one surface of a lens substrate. The method can be performed without the use of an adhesive during the application process. The film can be a coated film having one surface bearing a coating or a coating stack which is transferred from the film to the lens substrate main surface at the end of the application step, after withdrawal of the film.

1 . A process for applying a coated or uncoated film onto at least one surface of a lens substrate which comprises the steps of: 
 (a) providing a lens substrate having main surfaces;    (b) providing a coated or uncoated film;    (c) forming, on either a surface of the coated or uncoated film or one of the said surfaces of the lens substrate, a layer of a dry latex;    (d) despositing at least one drop of an aqueous solvent on either the said main surface of the lens substrate, a surface of the coated or uncoated film or an exposed surface of the dry latex layer;    (e) moving relatively to each other the coated or uncoated film and the lens substrate and applying a sufficient force to the coated or uncoated film to spread the aqueous solvent and form a thin pellicule of the aqueous solvent between the dry latex layer and either the lens substrate or the coated or uncoated film;    (f) heating the thin pellicle of aqueous solvent and the dry latex layer;    (g) releasing the applied force; and    (h) recovering the lens substrate with the coated or uncoated film adhered to the lens substrate main surface.    
   
   
       2 . The process of  claim 1 , wherein the aqueous solvent is selected from water and mixtures of water and at least one organic solvent.  
   
   
       3 . The process of  claim 2 , wherein the organic solvent is an alkanol or a mixture of alkanols.  
   
   
       4 . The process of  claim 1 , wherein the aqueous solvent is deionized water.  
   
   
       5 . The process of  claim 1 , wherein the dry latex layer is made of a latex selected from poly(meth) acrylic latex, polyurethane latex, polyester latex and mixtures thereof.  
   
   
       6 . The process of  claim 1 , wherein the lens substrate is made of a thermoplastic or thermosetting organic material.  
   
   
       7 . The process of  claim 6 , wherein the lens substrate is made of polycarbonate, thermoplastic or thermosetting polyurethanes, polythiourethanes, polyepoxides, polyepisulfides, poly(meth) acrylates, polythio(meth)acrylates, diethyleneglycol bis allylcarbonate copolymers and blends thereof.  
   
   
       8 . The process of  claim 1 , wherein the lens substrate main surface is chemically or physically pretreated.  
   
   
       9 . The process of  claim 8 , wherein the lens substrate main surface is pretreated by a corona discharge treatment.  
   
   
       10 . The process of  claim 1 , wherein the force applied on the coated or uncoated film in step (e) is obtained by application of a pressure or of a vacuum on the coated or uncoated film.  
   
   
       11 . The process of  claim 1 , wherein heating step (f) comprises heating at a temperature of 60 to 120° C.  
   
   
       12 . The process of  claim 1 , wherein the film is a coated film comprising a flexible carrier, a surface of which bears at least one coating.  
   
   
       13 . The process of  claim 12 , wherein the coating or coatings are selected from the group of functional coatings consisting of a hydrophobic top coat, an anti-reflective coating, an abrasion and/or scratch-resistant coating and an impact-resistant primer coating.  
   
   
       14 . The process of  claim 12 , further comprising a step (i) of withdrawal of the flexible carrier, whereby at the completion of the process the coating or coatings are transferred from the flexible carrier to the lens substrate main surface.  
   
   
       15 . The process of  claim 14 , wherein the coated film comprises in the indicated order, starting from the flexible carrier surface, a hydrophobic top coat, an anti-reflective coating, an abrasion and/or scratch-resistant coating and optionally an impact-resistant primer coating.  
   
   
       16 . The process of  claim 12 , wherein the coating or coatings are selected from the group of functional coatings consisting of a photochromic coating, a dye comprising coating, a polarized coating and a microstructured coating.  
   
   
       17 . The process of  claim 12 , wherein the coated film comprises at least one of topcoat, antireflective coating, abrasion resistant coating, and the dry latex forms an impact resistant coating on the coated lens substrate.  
   
   
       18 . The process of  claim 12 , wherein the dry latex layer is formed either on a main surface of the lens substrate, on an uncoated surface of the coated film, or on the at least one coating.  
   
   
       19 . The process of  claim 18 , wherein the dry latex layer is formed on the coating or coatings or on a lens substrate main surface.  
   
   
       20 . The process of  claim 12 , wherein the aqueous solvent is selected from water and mixtures of water with at least one organic solvent.  
   
   
       21 . The process of  claim 12 , wherein the aqueous solvent is deionized water.  
   
   
       22 . The process of  claim 12 , wherein the dry latex layer is made of a latex selected from poly(meth) acrylic latex, polyurethane latex, polyester latex or mixtures thereof.  
   
   
       23 . The process of  claim 12 , wherein the lens substrate is made of polycarbonate, thermoplastic or thermosetting polymethanes, polythiomethanes, polyepoxides, polyepisulfides, poly(meth), acrylates, diethyleneglycol bis allylcarbonate capolymers and blends thereof.  
   
   
       24 . The process of  claim 12 , wherein the lens substrate is pretreated by a corona discharge treatment.  
   
   
       25 . The process of  claim 12 , wherein the flexible carrier is made of thermoplastic material.  
   
   
       26 . The process of  claim 25 , wherein the thermoplastic material is made of polycarbonate.  
   
   
       27 . The process of  claim 12 , wherein the flexible carrier has a thickness of 0.2 to 5 mm.  
   
   
       28 . The process of  claim 12 , wherein the force applied on the coated film is obtained by application of an air pressure.  
   
   
       29 . The process of  claim 12 , wherein the carrier has a spheric shape and the lens substrate has a rear(concave) spheric, toric or progressive surface.  
   
   
       30 . The process of  claim 12 , wherein the carrier has a spheric shape and a convex surface bearing coating(s) to be transferred, and the lens substrate has a rear(concave) spheric, toric or progressive surface on which the coatings are to be transferred.  
   
   
       31 . The process of  claim 12 , wherein the lens substrate is polished or only fined without being polished.  
   
   
       32 . The process of  claim 1 , wherein the film is an uncoated film selected from the group consisting of a polarizing film, a coloured film, a photochromic film, an optical-electronical film, an electric-photochromic coating and a printed layer.  
   
   
       33 . The process of  claim 32 , wherein the dry latex is formed on a lens substrate main surface.  
   
   
       34 . The process of  claim 32 , wherein the dry latex layer is made of a latex selected from poly(meth) acrylic latex, polyurethane latex, polyester latex and mixtures thereof.  
   
   
       35 . The process of  claim 32 , wherein the lens substrate is made of polycarbonate, thermoplastic or thermosetting polyurethanes, polythiourethanes, polyepoxides, polyepisulfides, poly(meth) acrylates, diethyleneglycol bis allylcarbonate copolymers and blends thereof. +PG.30  
   
   
       36 . The process of  claim 32 , wherein the lens substrate main surface is pretreated by a corona discharge treatment.  
   
   
       37 . The process of  claim 32 , wherein the aqueous solvent is deionized water.  
   
   
       38 . The process of  claim 32 , wherein the force applied on the uncoated film is obtained by application of a vacuum.