Method for producing a polycarbonate layered composite

Abstract

The invention relates to a method for making a structure with at least a first polymer layer and a second polymer layer, each made from a polycarbonate polymer based on bisphenol A, and in between the first polymer layer and the second polymer layer an intermediate layer being arranged, comprising the following steps: a) the intermediate layer is applied at least on a partial region of the first polymer layer, b) optionally the intermediate layer is dried, c) the first polymer layer is coated on the side, on which the intermediate layer is arranged, with a liquid preparation comprising a solvent or a mixture of solvents and a polycarbonate derivative based on a geminally disubstituted dihydroxydiphenyl cycloalkane, the preparation covering the intermediate layer, d) optionally a drying step is made after step c), e) after step c) or step d), the second polymer layer is placed on the first polymer layer, covering the intermediate layer, f) the first polymer layer and the second polymer layer are laminated with each other under pressure, at a temperature from 120° C. to 230° C. and for a defined time.

1 . A method for making a structure with at least one first polymer layer ( 1 ) and a second polymer layer ( 2 ), each said layer is made from a polycarbonate polymer based on bisphenol A, and in between the first polymer layer ( 1 ) and the second polymer layer ( 2 ) is an intermediate layer ( 3 ) being arranged, comprising the following steps:
 a) applying the intermediate layer ( 3 ) at least on a partial region of the first polymer layer ( 1 ),   b) optionally, drying the intermediate layer ( 3 ),   c) coating the first polymer layer ( 1 ) on the side, on which the intermediate layer ( 3 ) is arranged, with a liquid preparation comprising a solvent or a mixture of solvents and a polycarbonate derivative based on a geminally disubstituted dihydroxydiphenyl cycloalkane, the preparation covers the intermediate layer ( 3 ),   d) optionally, drying after step c),   e) after step c) or step d), placing the second polymer layer ( 2 ) on the first polymer layer ( 1 )-covering the intermediate layer ( 2 ), and   f) laminating the first polymer layer ( 1 ) and the second polymer layer ( 2 ) with each other under pressure, at a temperature from 120° C. to 230° C. and for a defined time.   
     
     
         2 . A method according to  claim 1 , wherein the intermediate layer ( 3 ) is a printing layer, in particular comprising a security printing element and/or a printed photographic representation, a photographic emulsion, and/or a film, in particular a diffractive security film. 
     
     
         3 . The method according to  claim 1 , wherein the polycarbonate derivative has an average molecular weight (mean weight) of at least 10,000, preferably from 20,000 to 300,000. 
     
     
         4 . The method according to  claim 1 , wherein the polycarbonate derivative comprises functional carbonate structure units of formula (I), 
       
         
           
           
               
               
           
         
       
       wherein 
       R 1  and R 2  are independently from each other hydrogen, halogen, preferably chlorine or bromine, C 1 -C 8  alkyl, C 5 -C 6  cycloalkyl, C 6 -C 10  aryl, preferably phenyl, and C 7 -C 12  aralkyl, preferably phenyl-C 1 -C 4  alkyl, in particular benzyl, 
       m is an integer from 4 to 7, preferably 4 or 5, 
       R 3  and R 4  can be individually selected for each X, and independently represent hydrogen or C 1 -C 6  alkyl 
       X is carbon and 
       n is an integer greater than 20, 
       with the proviso that at least one atom X, R 3  and R 4  are both alkyl. 
     
     
         5 . The method according to  claim 4 , wherein at 1 to 2 atoms X, in particular at only one atom X, R 3  and R 4  are both alkyl. 
     
     
         6 . The method according to  claim 4 , wherein R 3  and R 4  are methyl. 
     
     
         7 . The method according to  claim 4 , wherein the X atoms in the alpha position to the diphenyl-substituted C atom (C1) are not dialkyl-substituted. 
     
     
         8 . The method according to  claim 4 , wherein the X atoms in the beta position to C1 are disubstituted with alkyl. 
     
     
         9 . The method according to  claim 4 , wherein m is 4 or 5. 
     
     
         10 . The method according to  claim 4 , wherein the polycarbonate derivative is based on
 4,4′-(3,3,5-timethyl cyclohexane-1,1-diyl) diphenol,   4,4′-(3,3-dimethyl cyclohexane-1,1-diyl) diphenol, or   4,4′-(2,4,4-trimethyl cyclopentane-1,1-diyl) diphenol.   
     
     
         11 . The method according to  claim 1 , wherein the polycarbonate derivative comprises a copolymer in particular consisting of monomer units M1 based on formula (Ib) and monomer units M2 based on the geminally disubstituted dihydroxydiphenyl cycloalkane, preferably of the 4,4′-(3,3,5-trimethyl cyclohexane-1,1-diyl) diphenol, wherein the molar ratio M2/M1 preferably is greater than 0.3, in particular greater than 0.4, preferably greater than 0.5. 
     
     
         12 . The method according to  claim 1 , wherein the temperature in step f) is in the range from 140° C. to 200° C., in particular in the range from 150° C. to 180° C. 
     
     
         13 . The method according to  claim 1 , wherein the first polycarbonate layer ( 1 ) and the second polycarbonate layer ( 2 ) have a glass temperature Tg of more than 145° C. 
     
     
         14 . The method according to  claim 1 , wherein the thickness of the first polycarbonate layer ( 1 ) and of the second polycarbonate layer ( 2 ) is identically or different in the range from 10 to 1,000 μm, in particular from 20 to 200 μm. 
     
     
         15 . The method according to  claim 1 , wherein the thickness, measured in directions orthogonal to a main face of a polycarbonate layer ( 1 ,  2 ), of the intermediate layer ( 3 ) is in the range from 0.1 to 1,000 μm, in particular from 1 to 50 μm. 
     
     
         16 . A structure obtainable with a method according to  claim 1 . 
     
     
         17 . A structure comprising at least one first polycarbonate layer ( 1 ), a second polycarbonate layer ( 2 ), an intermediate layer ( 3 ) arranged between the first polycarbonate layer ( 1 ) and the second polycarbonate layer ( 2 ) and a preparation layer ( 4 ) connecting the intermediate layer ( 3 ) with the second polycarbonate layer ( 2 ) and comprising a polycarbonate derivative based on a geminally disubstituted dihydroxydiphenyl cycloalkane. 
     
     
         18 . The use of a method according to  claim 1  for making a security and/or value document, wherein optionally simultaneously with, before or after the production of the structure, the first polycarbonate layer ( 1 ) and/or the second polycarbonate layer ( 2 ) are directly or indirectly connected with at least one additional layer, for instance a carrier layer. 
     
     
         19 . The security and/or value document obtainable according to  claim 18 . 
     
     
         20 . The security and/or value document comprising a structure according to  claim 16 .