Photochromic coating process

Abstract

The present invention provides a method for manufacturing a photochromic article having a photochromic compound containing layer. The method includes the step of coating a casting face of at least one mould section with a photochromic host layer. The photochromic host layer is treated to minimise damage during subsequent steps, and a mould is then assembled so that it includes the mould section having the photochromic host layer. The mould is then filled with a photochromic article monomer composition and the monomer composition is subsequently cured to form a photochromic article substrate adhered to the photochromic host layer. The photochromic compound is introduced into the photochromic host layer.

1 - 45 . (canceled)  
     
     
         46 . A method for manufacturing a photochromic article, the method including the steps of: 
 forming a photochromic host layer on the casting face of at least one mould section,    treating the photochromic host layer to minimise damage during subsequent steps,    filling an assembled mould that includes the mould section having the photochromic host layer with a substrate monomer composition,    curing the substrate monomer composition to form a solid article that includes the photochromic host layer, and    introducing a photochromic compound into the photochromic host layer to form the photochromic article.    
     
     
         47 . A method as in  claim 46  wherein the photochromic host layer has a thickness of between 10 and 150 microns.  
     
     
         48 . A method as in  claim 46  wherein the photochromic host layer has a thickness of between 25 and 60 microns.  
     
     
         49 . A method as in  claim 46  wherein the photochromic host layer has a thickness of between 30 and 50 microns.  
     
     
         50 . A method as in  claim 47  wherein the photochromic compound is introduced into the photochromic host layer after the solid article has been removed from the mould.  
     
     
         51 . A method as in  claim 46  wherein the photochromic host layer is at least partially cured and/or solvent is evaporated from the photochromic host layer in order to minimise damage to the photochromic host layer during subsequent steps.  
     
     
         52 . A method as in  claim 50  wherein the photochromic host layer is at least partially cured to minimise damage during subsequent steps and it is subsequently completely cured either during or after the photochromic compound has been introduced into the photochromic host layer.  
     
     
         53 . A method as in  claim 46  wherein the photochromic host layer is formed from a coating monomer composition that forms a relatively non-polar polymer.  
     
     
         54 . A method as in  claim 46  wherein the photochromic article is formed with a photochromic host layer having a Tg of at least 40° Celsius.  
     
     
         55 . A method as in  claim 46  wherein the photochromic host layer is formed from a host layer monomer composition that contains any one or more of: alkylene mono- or poly(meth)acrylates; poly(alkyleneoxide) mono- or poly(meth)acrylates; urethane mono- or poly(meth)acrylates and allyl compounds.  
     
     
         56 . A method as in  claim 55  wherein the poly(alkyleneoxide) poly(meth)acrylate is a monomer containing a major portion of nonaethylene glycol dimethacrylate.  
     
     
         57 . A method as in  claim 55  wherein the poly(alkyleneoxide) poly (meth)acrylate is a monomer containing a major portion of quatdecaethylene glycol dimethacrylate.  
     
     
         58 . A method as in  claim 55  wherein the poly(alkyleneoxide) poly (meth)acrylate is a polytetramethylene glycol monomer.  
     
     
         59 . A method as in  claim 46  wherein the photochromic host layer is formed from a host layer monomer composition that contains an ethoxylated bisphenol-A dimethacrylate monomer having between 1 and 20 ethoxy groups per molecule.  
     
     
         60 . A method as in  claim 56  wherein the host layer monomer composition includes a minor proportion of a hardening monomer that provides rigidity when cured.  
     
     
         61 . A method as in  claim 60  wherein the hardening monomer is a urethane acrylate, an ethoxylated bisphenol-A dimethacrylate monomer having between 1 and 20 ethoxy groups per molecule or an isocyanurate based poly(meth)acrylate.  
     
     
         62 . A method as in  claim 61  wherein the hardening monomer is added in amount of 1 to 35% by weight of the host layer monomer composition.  
     
     
         63 . A method as in  claim 61  wherein the hardening monomer is added in amount of 5 to 15% by weight of the host layer monomer composition.  
     
     
         64 . A method as in  claim 62  wherein the nanoindentation depth of the photochromic host layer is between about 9000 nm and about 2500 nm.  
     
     
         65 . A method as in  claim 46  wherein the photochromic article is an ophthalmic lens.  
     
     
         66 . A method for manufacturing a photochromic article, the method including the steps of: 
 forming a photochromic host layer on the casting face of at least one mould section,    treating the photochromic host layer to minimise damage during subsequent steps,    applying a barrier layer to the photochromic host layer,    filling an assembled mould that includes the mould section having the photochromic host layer with a substrate monomer composition,    curing the substrate monomer composition to form a solid article that includes the photochromic host layer, and    introducing a photochromic compound into the photochromic host layer either before or after the step of curing the substrate monomer composition.    
     
     
         67 . A method as in  claim 66  wherein the barrier layer minimises penetration of the substrate monomer composition into the photochromic host layer.  
     
     
         68 . A method as in  claim 67  wherein the photochromic host layer has a thickness of between 10 and 150 microns.  
     
     
         69 . A method as in  claim 67  wherein the photochromic host layer has a thickness of between 25 and 60 microns.  
     
     
         70 . A method as in  claim 67  wherein the photochromic host layer has a thickness of between 30 and 50 microns.  
     
     
         71 . A method as in  claim 67  wherein the barrier layer is formed by polymersing a mixture that includes a compound containing double bonds and a compound containing thiol groups.  
     
     
         72 . A method as in  claim 67  wherein the barrier layer is formed by polymersing a mixture that includes a compound containing isocyanate groups and a compound containing thiol, hydroxy or aromatic amine groups.  
     
     
         73 . A method as in  claim 67  wherein the photochromic host layer is at least partially cured and/or solvent is evaporated from the photochromic host layer in order to minimise damage to the photochromic host layer.  
     
     
         74 . A method as in  claim 73  wherein the photochromic compound is introduced into the photochromic host layer after the solid article has been removed from the mould.  
     
     
         75 . A method as in  claim 67  wherein the photochromic host layer is formed from a host layer monomer composition that contains any one or more of: alkylene mono- or poly(meth)acrylates; poly(alkyleneoxide) mono- or poly(meth)acrylates; urethane mono- or poly(meth)acrylates; and allyl compounds.  
     
     
         76 . A method as in  claim 75  wherein the poly(alkyleneoxide) poly(meth)acrylate is a monomer containing a major portion of nonaethylene glycol dimethacrylate.  
     
     
         77 . A method as in  claim 75  wherein the poly(alkyleneoxide) di(meth)acrylate is a monomer containing a major portion of quatdecaethylene glycol dimethacrylate.  
     
     
         78 . A method as in  claim 75  wherein the poly(alkyleneoxide) di(meth)acrylate is a polytetramethylene glycol monomer.  
     
     
         79 . A method as in  claim 67  wherein the photochromic host layer is formed from a coating monomer composition that contains an ethoxylated bisphenol-A dimethacrylate monomer having between 1 and 20 ethoxy groups per molecule.  
     
     
         80 . A photochromic article prepared by the method of  claim 46 .  
     
     
         81 . A method for manufacturing a photochromic article wherein physical and/or chemical properties of a photochromic host layer can be adjusted to alter the transition time of photochromic compounds contained in that layer, the method including the step of adjusting one or more of the polarity and/or the local rigidity of the photochromic host layer to either increase or decrease the transition time of the photochromic compounds.  
     
     
         82 . A method as in  claim 81  wherein the transition time of the photochromic compound is controlled by including a hardening monomer in the photochromic host layer.  
     
     
         83 . A method as in  claim 82  wherein the hardening monomer is a urethane acrylate, an ethoxylated bisphenol-A dimethacrylate monomer having between 1 and 20 ethoxy groups per molecule or an isocyanurate based poly(meth)acrylate.  
     
     
         84 . A method as in  claim 83  wherein the urethane acrylate is U-4HA or U-6HA.  
     
     
         85 . A method as in  claim 84  wherein the photochromic host layer is formed from a coating monomer composition that contains nonaethyleneglycol dimethacrylate.  
     
     
         86 . A method as in  claim 84  wherein the hardening monomer is present in an amount of 1 to 35%.  
     
     
         87 . A method as in  claim 84  wherein the hardening monomer is present in an amount of 5 to 15%.