Materials for high density optical recording media

Abstract

Materials for optical recording media are disclosed. Specifically, the materials are metal chelate compounds of azo dyes, which are formed from sulfamoylated m-diaminobenzene compounds and benzene ring-containing azo compounds. Further, the invention provides an optical recording medium, characterized in that said metal chelate compounds of azo dyes are employed onto the optical recording medium to form a recording layer. The invention also discloses a process for the production of an optical recording medium.

1 . A process for the preparation of high density optical recording media, comprising a recording layer and a reflective layer formed on a substrate in order, characterized in that the recording layer is coated with an azo metal chelate compound of formula (I): 
       
         
           
           
               
               
           
         
       
       in which
 R 1  represents C 1-6 alkyl, phenyl or C 1-6 alkyl-substituted phenyl; 
 R 2  and R 3 , independently of each other, represent the same or different C 1-6 alkyl, optionally substituted by C 1-6 alkyl; 
 W represents hydrogen, C 1-6 alkyl, C 1-6 alkoxy or halogen; 
 X represents hydrogen, C 1-6  alkyl, C 1-6 alkoxy or halogen; 
 Y represents hydrogen or an amino derivative; 
 Z represents hydrogen, C 1-6 alkyl, C 1-6 alkoxy or halogen; 
 M represents a divalent metal selected from Group IB, IIB or VIIIB in Periodic Table, comprising the steps of: 
 1) preparing a round polymer substrate having an outer diameter of 120 mm, an inner diameter of 15 mm, a thickness of 0.6 mm by an infection molding machine and forming continuous spiral grooves having a depth of 150 to 180 nm, a half-height width of 340 to 380 nm, a bottom width of 260 to 280 nm thereon by printing with a stamper, 
 2) dissolving the materials according to any one of  claims 1  to  4  in solvents to form a 1.5% solution of azo metal chelate compounds, followed by spin coating the substrate with the dye solution, 
 3) obtaining an absorption at the maximal absorption wavelength in a range of 0.7 to 0.8 after coating the recording layer with the dye solution, determined by UV-Visible Spectroscopy, 
 4) baking the coating at a temperature of 60 to 80° C. for 10 to 20 minutes to evaporate off solvents, 
 5) forming an about 120 nm gold film as a reflective layer on the recording layer containing a dye by a sputtering machine, then spin coating said substrate with a lacquer and curing it to form a protective layer, and 
 6) coating the protective layer with a layer of adhesive by screen printing or spin coating, on which a transparent polymer substrate having a thickness of 0.6 mm and an outer diameter of 120 mm is attached, to obtain a recordable optical recording medium with a thickness of 1.2 to 1.25 mm and an outer diameter of 120 mm. 
 
     
     
         2 . A process for the preparation of high density optical recording media according to  claim 1 , wherein R 1  is selected from the group consisting of methyl, phenyl or methylphenyl; R 2  and R 3 , independently of each other, represent identical or different methyl or ethyl comprising the steps of:
 1) preparing a round polymer substrate having an outer diameter of 120 mm, an inner diameter of 15 mm, a thickness of 0.6 mm by an infection molding machine and forming continuous spiral grooves having a depth of 150 to 180 nm, a half-height width of 340 to 380 nm, a bottom width of 260 to 280 nm thereon by printing with a stamper,   2) dissolving the materials according to any one of  claims 1  to  4  in solvents to form a 1.5% solution of azo metal chelate compounds, followed by spin coating the substrate with the dye solution,   3) obtaining an absorption at the maximal absorption wavelength in a range of 0.7 to 0.8 after coating the recording layer with the dye solution, determined by UV-Visible Spectroscopy,   4) baking the coating at a temperature of 60 to 80° C. for 10 to 20 minutes to evaporate off solvents,   5) forming an about 120 nm gold film as a reflective layer on the recording layer containing a dye by a sputtering machine, then spin coating said substrate with a lacquer and curing it to form a protective layer, and   6) coating the protective layer with a layer of adhesive by screen printing or spin coating, on which a transparent polymer substrate having a thickness of 0.6 mm and an outer diameter of 120 mm is attached, to obtain a recordable optical recording medium with a thickness of 1.2 to 1.25 mm and an outer diameter of 120 mm.   
     
     
         3 . A process for the preparation of high density optical recording media according to  claim 1 , wherein W represents hydrogen, methyl, methoxy or chloro; X represents hydrogen, methyl or methoxy; Y represents hydrogen or benzamido (NBz); Z represents hydrogen, methyl or methoxy comprising the steps of:
 1) preparing a round polymer substrate having an outer diameter of 120 mm, an inner diameter of 15 mm, a thickness of 0.6 mm by an infection molding machine and forming continuous spiral grooves having a depth of 150 to 180 nm, a half-height width of 340 to 380 nm, a bottom width of 260 to 280 nm thereon by printing with a stamper,   2) dissolving the materials according to any one of  claims 1  to  4  in solvents to form a 1.5% solution of azo metal chelate compounds, followed by spin coating the substrate with the dye solution,   3) obtaining an absorption at the maximal absorption wavelength in a range of 0.7 to 0.8 after coating the recording layer with the dye solution, determined by UV-Visible Spectroscopy,   4) baking the coating at a temperature of 60 to 80° C. for 10 to 20 minutes to evaporate off solvents,   5) forming an about 120 nm gold film as a reflective layer on the recording layer containing a dye by a sputtering machine, then spin coating said substrate with a lacquer and curing it to form a protective layer, and   6) coating the protective layer with a layer of adhesive by screen printing or spin coating, on which a transparent polymer substrate having a thickness of 0.6 mm and an outer diameter of 120 mm is attached, to obtain a recordable optical recording medium with a thickness of 1.2 to 1.25 mm and an outer diameter of 120 mm.   
     
     
         4 . A process for the preparation of high density optical recording media according to  claim 1 , wherein the divalent metal M represents Ni, Cu or Zn comprising the steps of:
 1) preparing a round polymer substrate having an outer diameter of 120 mm, an inner diameter of 15 mm, a thickness of 0.6 mm by an infection molding machine and forming continuous spiral grooves having a depth of 150 to 180 nm, a half-height width of 340 to 380 nm, a bottom width of 260 to 280 nm thereon by printing with a stamper,   2) dissolving the materials according to any one of  claims 1  to  4  in solvents to form a 1.5% solution of azo metal chelate compounds, followed by spin coating the substrate with the dye solution,   3) obtaining an absorption at the maximal absorption wavelength in a range of 0.7 to 0.8 after coating the recording layer with the dye solution, determined by UV-Visible Spectroscopy,   4) baking the coating at a temperature of 60 to 80° C. for 10 to 20 minutes to evaporate off solvents,   5) forming an about 120 nm gold film as a reflective layer on the recording layer containing a dye by a sputtering machine, then spin coating said substrate with a lacquer and curing it to form a protective layer, and   6) coating the protective layer with a layer of adhesive by screen printing or spin coating, on which a transparent polymer substrate having a thickness of 0.6 mm and an outer diameter of 120 mm is attached, to obtain a recordable optical recording medium with a thickness of 1.2 to 1.25 mm and an outer diameter of 120 mm.   
     
     
         5 . The process according to  claim 1 , wherein the substrate is polycarbonate. 
     
     
         6 . The process according to  claim 2 , wherein the substrate is polycarbonate. 
     
     
         7 . The process according to  claim 3 , wherein the substrate is polycarbonate. 
     
     
         8 . The process according to  claim 4 , wherein the substrate is polycarbonate.