Laser-markable paper and board products

Abstract

The present invention relates to laser-markable paper and board products, characerized in that they comprise, as absorber material, inorganic platelet-form substrates having a particle size of from 1 to 60 μm.

1 . A laser-markable product comprising a single layer comprising pulp fibers and an absorber material, wherein the absorber material comprises inorganic platelet-form substrates with a particle size consisting of 1 μm-60 μm, wherein the inorganic platelet-form substrates comprise a mixture of different inorganic platelet-form substrates, comprising mica, a pearl luster pigment, and an electrically conductive pigment, and the product comprises 1% to 5% by weight of the absorber material based on the product.  
   
   
       2 . A laser-markable product according to  claim 1 , further comprising color pigments.  
   
   
       3 . A laser-markable product according to  claim 1 , further comprising light-sensitive pigments.  
   
   
       4 . A process for producing a laser-markable product according to  claim 1 , comprising stirring absorber material into pulp fibers and/or into a coating material during a papermaking process.  
   
   
       5 . A laser-markable product according to  claim 1 , wherein the product is a paper or board product.  
   
   
       6 . A laser-markable product comprising pulp fibers and an absorber coating of a thickness suitable for laser marking having a pale intrinsic color and comprising inorganic platelet-form substrates.  
   
   
       7 . A method of marking a laser-markable product, comprising exposing to laser radiation a laser-markable product comprising a single layer, comprising pulp fibers and an absorber material having a pale intrinsic color and, in turn, comprising inorganic platelet-form substrates with a particle size of 1 μm-60 μm.  
   
   
       8 . A method of marking a laser-markable product comprising exposing to laser radiation the laser-markable product according to  claim 1 .  
   
   
       9 . A packaging material, a security document, a security paper or a graphic product markable by or marked with a laser, comprising a laser-markable product according to  claim 1 .  
   
   
       10 . A laser-markable product according to  claim 1  comprising a homogenous distribution of pulp fibers and inorganic platelet-form substrates.  
   
   
       11 . A laser-markable product according to  claim 10 , wherein the product consists of a single layer.  
   
   
       12 . A laser-markable product according to  claim 6 , wherein the product is a paper or board product.