Pearlescent Metallic Effect Paper Material With High Lightfastness And Related Manufacturing Method

Abstract

The paper material comprises a base support, made up of a mixture of cellulose fibres containing at least one polymeric substance, which is adapted to give the mixture of fibres mechanical strength, and an inorganic filler, said base support having at least one surface treated with at least one surface adhesive and at least one coating applied on said treated surface, the coating comprising at least pearlescent pigments of high lightfastness.

1 . A paper material comprising a base support, made up of a mixture of cellulose fibres comprising at least one polymeric substance, which is adapted to give the mixture of fibres mechanical strength, and an inorganic filler, said base support having at least one coating applied on said treated surface, wherein said coating comprises at least pearlescent pigments of high lightfastness. 
     
     
         2 . The paper material according to  claim 1 , wherein said pearlescent pigments are of various colours, particle sizes and shapes. 
     
     
         3 . The paper material according to  claim 1 , wherein said coating comprises one or more binder polymers or waxes, in a mixture with said pearlescent pigments. 
     
     
         4 . The paper material according to  claim 1 , wherein said coating comprises one or more binder polymers or waxes, in a mixture with said pearlescent pigments and with magnetic or diamagnetic metallic pigments. 
     
     
         5 . The paper material according to  claim 1 , wherein said pearlescent pigments are borosilicates or aluminosilicates. 
     
     
         6 . The paper material according to  claim 5 , wherein said pearlescent pigments are transparent borosilicates or aluminosilicates coated with metal oxides. 
     
     
         7 . The paper material according to  claim 1 , wherein the polymeric substance included in the base support comprises one or more colophony-based, alkyl-ketene-dimer-based, acetylsuccinic-acid-based, or epochlorohydrin-based resins, or modified starches. 
     
     
         8 . The paper material according to  claim 1 , wherein the inorganic filler is a mineral filler comprising one or more substances selected from the group consisting of carbonates, kaolins, talc and mixtures thereof. 
     
     
         9 . The paper material according to  claim 1 , wherein the surface adhesive is an adhesive based on starch, polyvinyl alcohol, acrylic, polyurethane or styrene-butadiene polymers. 
     
     
         10 . The paper material according to  claim 3 , wherein the binder polymers comprise at least one of polyurethane-, acrylic-, polyvinyl alcohol-, styrene-butadiene or silicone based polymers. 
     
     
         11 . A method for manufacturing a paper material, comprising the steps of:
 preparing an aqueous pulp of cellulose fibres, comprising at least one polymeric substance adapted to give the fibres mechanical strength, and an inorganic filler;   removing water from the pulp so as to form a base support of the paper material;   treating at least one surface of the base support with at least one surface adhesive;   performing a smoothing process on the treated surface of the base support; and   applying a coating comprising at least pearlescent pigments of high lightfastness to the smoothed treated surface.   
     
     
         12 . The method according to  claim 11 , wherein the treated surface is smoothed up to Bendsten ISO 2494 roughness values of less than approximately 450 ml/min., preferably of less than approximately 400 ml/min. and approximately around 350 ml/min. 
     
     
         13 . The method according to  claim 11 , wherein the coating applied to the treated surface comprises, in a mixture, said pearlescent pigments, magnetic or diamagnetic metallic pigments, and one or more binder polymers or waxes. 
     
     
         14 . The method according to  claim 11 , wherein the step of applying the coating takes place by spreading with an air knife or a smooth blade. 
     
     
         15 . The method according to  claim 11 , further comprising a step of drying the coating, carried out in an infrared and/or hot-air oven at a temperature within the range of 100° C. approximately to 180° C. approximately and with an oven time ranging between 0.5 and 4 minutes. 
     
     
         16 . The method according to  claim 15 , wherein, after drying the coating, a step of mechanically treating the surface provided with the coating is performed, particularly a smoothing step or an embossing step.