Composite paper pulp composition and method of making

Abstract

Composite pulp compositions for making paper are disclosed that include agricultural residue fibers, softwood fibers, and water. The composite pulp compositions are made by blending an agricultural residue with softwood chips and simultaneously and mechanically pulping the mixture of agricultural residue and softwood in one or more TMP and/or RMP operations. The agricultural residue is present in an amount in a range from about 1% to about 30% of the oven dry weight of the composite pulp composition. Co-pulping the agricultural residue with the softwood improves the tear strength properties of the composite pulp composition. Blended pulp compositions are also disclosed that include a chemical pulp or chemi-mechanical pulp blended with the composite pulp compositions having agricultural residue fibers and softwood fibers. Paper products made from the composite pulp compositions and blended pulp compositions are also disclosed herein.

What is claimed is: 
     
         1 . A process for making a composite pulp composition comprising:
 providing an agricultural residue;   providing a softwood;   combining the agricultural residue with the softwood to form a composite mixture; and   subjecting the composite mixture to one or more TMP operations and/or one or more RMP operations.   
     
     
         2 . The process of  claim 1 , wherein the composite mixture is subjected to one or more TMP operations and one or more RMP operations. 
     
     
         3 . The process of  claim 1 , further comprising:
 subjecting the composite mixture to a TMP operation to produce a first intermediate pulp;   subjecting the first intermediate pulp to a first RMP operation to produce a second intermediate pulp; and   subjecting the second intermediate pulp to a second RMP operation to produce the composite pulp composition.   
     
     
         4 . The process of  claim 3 , wherein the first RMP operation utilizes a disc refiner having plates spaced apart by a first distance, and the second RMP operation utilizes a disc refiner having plates spaced apart a second distance, wherein the second distance is the same as or less than the first distance. 
     
     
         5 . The process of  claim 1 , further comprising collecting the composite pulp composition for use in a paper-making process. 
     
     
         6 . The process of  claim 1 , wherein co-pulping of the agricultural residue with the softwood causes hemicelluloses in the agricultural residue to deposit on surfaces of one or more softwood fibers. 
     
     
         7 . The process of  claim 1 , wherein the agricultural residue is one or more of a corn stover, wheat straw, oat straw, canola straw, barley residue, flax straw, rice straw, sugar cane bagasse, abaca, hemp, kenaf, switchgrass, or combinations thereof. 
     
     
         8 . The process of  claim 1 , further comprising size-reducing the agricultural residue. 
     
     
         9 . The process of  claim 8 , wherein size-reducing the agricultural residue includes one or more of grinding, chopping, or milling the agricultural residue into a plurality of discrete pieces. 
     
     
         10 . The process of  claim 1 , further comprising screening the agricultural residue to provide a consistently-sized agricultural residue to the TMP operation. 
     
     
         11 . The process of  claim 1 , wherein an amount of the agricultural residue in the composite mixture is in a range of about 1% to about 30% per oven dry weight of the composite mixture. 
     
     
         12 . The process of  claim 1 , wherein the agricultural residue comprises a mixture of a first agricultural residue and a second agricultural residue different than the first agricultural residue, wherein an amount of the first agricultural residue is in a range of about 1% to about 50% of the oven dry weight of the mixture, the balance of the mixture being the second agricultural residue. 
     
     
         13 . The process of  claim 1 , wherein one or more of the TMP operation or RMP operation utilizes a disc refiner having a first plate and a second plate rotating relative to the first plate. 
     
     
         14 . The process of  claim 13 , wherein a distance between the first plate and the second plate is in a range of about 0.005 to about 0.012 inches. 
     
     
         15 . The process of  claim 1 , further comprising bleaching the composite pulp composition. 
     
     
         16 . The process of  claim 15 , wherein the bleaching includes contacting the composite pulp composition with hydrogen peroxide. 
     
     
         17 . The process of  claim 1 , further comprising adding a chemical pulp or chemi-mechanical pulp to the composite pulp composition to make a blended composite pulp composition. 
     
     
         18 . A composite pulp composition manufactured by the process of  claim 1 . 
     
     
         19 . A paper product made from the composite pulp composition of  claim 18 . 
     
     
         20 . The paper product of  claim 19 , further comprising a secondary pulp composition, wherein the secondary pulp composition is made from one or more of a chemical or chemi-mechanical process. 
     
     
         21 . A process for making a composite pulp composition for making paper products, the process comprising:
 providing an agricultural residue;   providing a softwood;   combining the agricultural residue with the softwood to form a composite mixture;   subjecting the composite mixture to a TMP operation to produce a first intermediate pulp;   subjecting the first intermediate pulp to a first RMP operation to produce a second intermediate pulp; and   subjecting the second intermediate pulp to a second RMP operation to produce the composite pulp composition.   
     
     
         22 . A composite pulp composition for making a paper product, the pulp composition comprising:
 agricultural residue fibers;   softwood fibers; and   water;   wherein an agricultural residue and softwood chips are mixed together and simultaneously and mechanically pulped in one or more of a TMP or RMP operation such that hemicellulose from the agricultural residue fibers is deposited on the softwood fibers to impart additional strength to the composite pulp composition.   
     
     
         23 . A composite pulp composition for making a paper product, the composite pulp composition manufactured by a process comprising the steps of:
 providing an agricultural residue;   providing a softwood;   co-pulping the agricultural residue and the softwood in one or more of a TMP or RMP operation.   
     
     
         24 . The composite pulp composition of  claim 23 , wherein an amount of agricultural residue fibers from the agricultural residue is in a range of about 1% to about 30% of the oven dry weight of the composite pulp composition. 
     
     
         25 . The composite pulp composition of  claim 24 , wherein the agricultural residue comprises a first agricultural residue and a second agricultural residue, wherein an amount of the first agricultural residue is in a range of about 1% to about 50% of the oven dry weight of the agricultural residue in the composite pulp composition. 
     
     
         26 . A composite pulp composition for making paper, the composite pulp composition comprising:
 agricultural residue fibers, wherein a portion of the agricultural residue fibers comprises hemicellulose;   softwood fibers; and   water;   wherein at least a portion of the hemicellulose is partially or fully deposited on the softwood fibers and a content of the agricultural residue fibers is in a range of about 1% to about 30% of the oven dry weight of the composite pulp composition.   
     
     
         27 . A paper composition comprising:
 chemical-processed pulp fibers or chemi-mechanical-processed pulp fibers in an amount in a range of about 1% to about 25% of the oven dry weight of the paper composition; and   agricultural residue fibers; and   softwood fibers;   wherein the agricultural residue fibers and the softwood fibers have been co-pulped in one or more TMP or RMP operations, wherein an amount of the agricultural residue fibers is in a range of about 0.1% to about 30% per oven dry weight of the agricultural residue fibers and the softwood fibers, and wherein hemicellulose from the agricultural residue fibers is deposited on the softwood fibers.