Multi-ply paper containing used paper fibers and additional fibers

Abstract

A paper formed of at least two layers of different compositions couched together. A first layer forms a carrier layer. A second layer forms a cover layer. The paper contains waste paper fibers and additional fibers in the form of fibers other than waste paper fibers. The additional fibers contain a proportion of fibers from the cup plant ( Silphium perfoliatum ). fibers from fruits and/or the barks of trees of the baobab genus ( Adansonia ), fibers from plants of the genus Cannabis, and/or fibers originating from residues of biogas facilities. The carrier layer has a proportion of additional fibers equal to 0 to 75 wt %. The cover layer has a minimum proportion of additional fibers equal to about 8 wt % and a maximum proportion equal to about 80 wt %. The additional fibers in the cover layer is higher than the additional fibers content in the carrier layer.

1 . Paper comprising:
 at least two layers of different composition which are couched together;   wherein a first layer of the at least two layers forms a carrier layer;   wherein a second layer of the at least two layers forms a cover layer;   wherein the paper contains waste paper fibers and additional fibers in the form of fibers other than waste paper fibers;   wherein the additional fibers contain a proportion of fibers from one or more of the following:
 a cup plant ( Silphium perfoliatum ); 
 either a fruit or a tree bark of the baobab genus ( Adansonia ) 
 at least one plant of the genus  Cannabis ; and 
 fibers originating from a residue of biogas; 
   wherein a proportion of additional fibers of 0 to 75 wt % is contained in the carrier layer;   wherein a minimum proportion of additional fibers of 8 wt % and a maximum proportion of additional fibers of 80 wt % are contained in the cover layer; and   wherein a proportion of additional fibers in the cover layer is higher than the proportion of additional fibers in the carrier layer.   
     
     
         2 . The paper according to  claim 1 , wherein the proportion of additional fibers in the cover layer is at least 5 wt %; higher than the proportion of additional fibers in the carrier layer. 
     
     
         3 . The paper according to  claim 2 , wherein the additional fibers are also contained in the carrier layer. 
     
     
         4 . The paper according to  claim 1 , wherein the proportion of additional fibers in the carrier layer is at most 80 wt %. 
     
     
         5 . The paper according to  claim 1 , wherein the proportion of additional fibers in the cover layer is 20 to 70 wt %. 
     
     
         6 . The paper according to  claim 1 , wherein the minimum proportion of additional fibers in the cover layer is 25 wt %. 
     
     
         7 . The paper according to  claim 1 , wherein the carrier layer has a minimum proportion of waste paper fibers of 20 wt %. 
     
     
         8 . The paper according to  claim 1 , wherein the additional fibers also contain a proportion of fresh fibers and/or a proportion of grass fibers; wherein the grass fibers are in the form of fibers of sweet grass, sorrel, seagrass, or algae. 
     
     
         9 . The paper according to  claim 1 , wherein the proportion of fibers of the cup plant ( Silphium perfoliatum ), of fibers obtained from fruits and/or the bark of trees of the baobab genus ( Adansonia ), of fibers originating from plants of the genus  Cannabis,  or originating from the residue of the biogas facilities, in a fiber composition of the cover layer makes up at least 5 wt %, relative to a dry weight of the fibers introduced overall into the cover layer. 
     
     
         10 . The paper according to  claim 9 , wherein the paper contains no fresh fibers. 
     
     
         11 . The paper according to  claim 1 , wherein the carrier layer contains at least one type of waste paper fibers not contained within the cover layer. 
     
     
         12 . The paper according to  claim 11 , wherein waste paper fibers obtained from a white waste paper are contained in the cover layer, and a brown waste paper fibers are contained in the carrier layer. 
     
     
         13 . The paper according to  claim 11 , wherein waste paper fibers of a craft paper or a craft cardboard are contained in the carrier layer. 
     
     
         14 . The paper according to  claim 1 , wherein the paper has a basis weight of 80 to 200 g/m 2 . 
     
     
         15 . The paper according to  claim 14 , wherein the carrier layer has a basis weight of 60 to 170 g/m 2 . 
     
     
         16 . The paper according to  claim 14 , wherein the cover layer has a basis weight of 30 to 50 g/m 2 . 
     
     
         17 . The paper according to  claim 16 , wherein an interlaminar strength determined according to the International Scott Bond Test according to DIN ISO 16260 is equal to about 180 to 300 J/m 2 . 
     
     
         18 . The paper according to  claim 17 , wherein a Cobb 60  value of the cover layer according to DIN EN ISO 535 is equal to at most 40 g/m 2 . 
     
     
         19 . A method for producing a paper comprising the following steps performed in a paper machine:
 applying a first web of a first fibrous material composition containing water and waste paper fibers relative to a dry mass on a first screen;   applying a second web of a second fibrous material composition containing water, waste paper fibers in a maximum proportion of 80 wt %, relative to the dry mass, and additional fibers in the form of fibers other than waste paper fibers in a minimum proportion of 20 wt %, relative to the dry mass on a second screen, wherein the second fibrous material composition has a higher proportion of additional fibers than the first fibrous material composition;   couching the first web and the second web formed on the first screen and the second screen to form an at least two-layer paper web;   drying the at least two-layer paper web; and   wherein the additional fibers contain a proportion of fibers from any of the following: of a cup plant ( Silphium perfoliatum ), of fibers obtained from fruits and/or the bark of trees of the baobab genus ( Adansonia ), of fibers obtained from plants of the genus  Cannabis,  and/or of fibers originating from a residue of biogas facilities.   
     
     
         20 . The method according to  claim 19 , wherein the first web further comprises additional fibers in the form of fibers other than waste paper fibers in a maximum proportion of 50 wt % or less relative to the dry mass.