Novel material for infrared laser ablated engraved flexographic printing plates

Abstract

A non-photosensitive flexographic liquid or paste precursor comprising a mixture of acrylate oligomers and acrylic or methacrylate monomers, infrared absorbing material, fillers and heat decomposable peroxide, which when heated forms a non-thermoplastic elastomeric solid material in the form of a flexographic printing blank engraveable by infrared laser ablation.

1 . A non-photosensitive flexographic liquid or paste precursor comprising:
 a mixture of acrylate oligomers and acrylate or methacrylate monomers wherein this mixture has a viscosity of less than 2000 cps;   an infrared absorbing material;   a filler; and   a heat decomposable peroxide,   which flexographic liquid or paste precursor, when heated, forms a non-thermoplastic elastomeric solid material in the form of a flexographic printing blank that is directly engraveable by infrared laser ablation.   
     
     
         2 .- 5 . (canceled) 
     
     
         6 . The flexographic liquid or paste precursor of  claim 1 , wherein the infrared absorbing material comprises carbon black, nigrosine, or iron oxide. 
     
     
         7 - 9 . (canceled) 
     
     
         10 . The flexographic liquid or paste precursor of  claim 1 , additionally comprising anti-ozone additives. 
     
     
         11 . The flexographic liquid or paste precursor of  claim 1 , wherein the amount of infrared absorbing material comprises 4% to 20% by weight of the total flexographic liquid or paste precursor. 
     
     
         12 . (canceled) 
     
     
         13 . The flexographic liquid or paste precursor of  claim 1 , wherein the amount of heat decomposable peroxide comprises 1% to 12% by weight of the total flexographic liquid or paste precursor. 
     
     
         14 . (canceled) 
     
     
         15 . The flexographic liquid or paste precursor of  claim 1 , wherein the filler comprises a material that reduces the overall density of the resultant flexographic blank after heat curing. 
     
     
         16 . The flexographic liquid or paste precursor of  claim 1  wherein the filler is selected from the group comprising hollow plastic microspheres, filled plastic microspheres and poly(acrylonitrile-co-methyl acrylonitrile) microspheres. 
     
     
         17 . (canceled) 
     
     
         18 . The flexographic liquid or paste precursor of  claim 1 , wherein filler is an inert filler that is selected from the group comprising fumed silica, bentonite, glass microspheres and sodium pyrophosphate. 
     
     
         19 . The flexographic liquid or paste precursor of  claim 1 , wherein the mixture of acrylate oligomers and acrylate or methacrylate monomers comprises at least one urethane oligomer. 
     
     
         20 . The flexographic liquid or paste precursor of  claim 19 , wherein the at least one urethane oligomer comprises two acrylate groups per molecule. 
     
     
         21 . The flexographic liquid or paste precursor of  claim 1 , wherein the mixture of acrylate oligomers and acrylate or methacrylate monomers comprises at least 80% urethane diacrylate oligomer. 
     
     
         22 . (canceled) 
     
     
         23 . The flexographic liquid or paste precursor of  claim 1 , wherein the amount of acrylate oligomers is between 15% and 40% by weight of the total acrylate oligomers and acrylate or methacrylate monomer mixture. 
     
     
         24 - 28 . (canceled) 
     
     
         29 . The flexographic liquid or paste precursor of  claim 1 , wherein at least 80% by weight of the acrylate oligomers and acrylate or methacrylate monomer mixture is either mono-acrylate or mono-methacrylates and not di, tri, tetra, penta or more acrylate groups per molecule. 
     
     
         30 .- 31 . (canceled) 
     
     
         32 . The flexographic liquid or paste precursor of  claim 1 , wherein the acrylate oligomer and acrylate or methacrylate monomer mixture includes isobornyl acrylate or methacrylate. 
     
     
         33 . The flexographic liquid or paste precursor of  claim 1  that additionally comprises solvents in amounts below 5% by weight of the total precursor. 
     
     
         34 .- 46 . (canceled) 
     
     
         47 . A method of producing a non-photosensitive solid flexographic printing plate blank or sleeve blank for imaging by infrared ablation, comprising the steps of:
 providing a formulation mixture comprising:
 a mixture of acrylate oligomers and acrylate or methacrylate monomers wherein this mixture has a viscosity of less than 2000 cps; 
 an infrared absorbing material; 
 a filler; and 
 a heat decomposing peroxide; 
   filling a mold with the formulation mixture; and   heating the formulation mixture to cross-link it.   
     
     
         48 . The method of  claim 47 , additionally comprising the step of removing the air in the material by vacuum, before the step of heating. 
     
     
         49 . (canceled) 
     
     
         50 . A method of producing a non-photosensitive solid flexographic printing plate or sleeve, comprising the steps of:
 producing a non-photosensitive solid flexographic printing plate blank or sleeve blank by:   providing a formulation mixture comprising:
 a mixture of acrylate oligomers and acrylate or methacrylate monomers wherein this mixture has a viscosity of less than 2000 cps; 
 an infrared absorbing material; 
 a filler; and 
 a heat decomposing peroxide; 
   treating the mixture with vacuum to remove all occluded air;   filling a mold with the formulation mixture;   heating the formulation mixture to cross-link it;
 thereby forming a flexographic printing plate blank or sleeve blank, and 
   imaging the flexographic printing plate blank or sleeve blank by ablating with a high powered infrared laser.   
     
     
         51 . A method of producing a non-photosensitive solid flexographic printing plate or sleeve, comprising the steps of:
 producing a non-photosensitive solid flexographic printing plate blank or sleeve blank by:
 providing a formulation mixture comprising:
 a mixture of acrylate oligomers and acrylate or methacrylate monomers wherein this mixture has a viscosity of less than 2000 cps; 
 an infrared absorbing material; 
 a filler; and 
 a heat decomposing peroxide; 
 
 filling a mold with the formulation mixture; 
 heating the formulation mixture to cross-link it;
 thereby forming a flexographic printing plate blank or sleeve blank, and 
 
 imaging the flexographic printing plate blank or sleeve blank by ablating with a high powered infrared laser. 
   
     
     
         52 . (canceled)