Lightweight cardboard and paper articles

Abstract

Wet laid products such as cardboard, paperboard, and packaging and container board can be light-weighted or made thicker, while retaining Gurley stiffness. The wet laid products contain co-refined CE staple fibers that have: i. a denier per filament (DPF) of less than 3, or ii. a cut length of less than 6 mm, or iii. crimping, or iv. a combination of any two or more of (i)-(iv).

What we claim is: 
     
         1 . A wet laid product having a basis weight and thickness, said wet laid product comprising cellulose fibers and cellulose ester (CE) staple fibers, said CE staple fibers having:
 i. a denier per filament (DPF) of less than 3, or   ii. a cut length of less than 6 mm, or   iii. crimping, or   iv. a combination of any two or more of (i)-(iv); and   wherein the wet laid product has either:
 a) a basis weight that is lower than, or 
 b) a basis weight that is lower and a Gurley stiffness that is the same as, higher, or reduced by not more than 5%, 
   in each case measured relative to the same wet laid product obtained with a 100% cellulose comparative composition and the thickness of the wet laid product is within +/−5% the thickness of comparative wet laid product.   
     
     
         2 . The wet laid product of  claim 1 , wherein:
 a. the opacity of the wet laid product is maintained or increased, relative the opacity of a wet laid product obtained with a 100% cellulose comparative composition at within +/−5% equivalent thickness, or   b. the air permeability of the wet laid product is maintained or increased, relative the air permeability of a wet laid product obtained with a 100% cellulose comparative composition at within +/−5% equivalent thickness, or   c. both   
     
     
         3 . The wet laid product of  claim 1 , wherein said wet laid product comprises a paper having a basis weight of at least 80 g/m2. 
     
     
         4 . The wet laid product of  claim 1 , wherein the Gurley stiffness of the wet laid product is maintained or increased, relative to a comparative wet laid product. 
     
     
         5 . The wet laid product of  claim 1 , wherein said wet laid product is sanitary, toweling, packaging/container board or paperboard, or Kraft paper. 
     
     
         6 . The wet laid product of  claim 1 , wherein the cellulose fibers comprise waste/recycle cellulose fibers in an amount of at least 25 wt. %, based on the weight of all cellulose fibers present in the wet laid product. 
     
     
         7 . The wet laid product of  claim 1 , wherein the web has a Gurley stiffness, in mg force per microns thickness, of at least 1.15 mg force/microns thickness. 
     
     
         8 . The wet laid product of any of  claim 1 , wherein the CE staple fibers are co-refined. 
     
     
         9 . The wet laid product of  claim 1 , wherein the composition contains no plasticizer or not more than 0.3 wt. % plasticizer, based on the weight of the CE staple fibers. 
     
     
         10 . The wet laid product of  claim 1 , wherein the amount of CE staple fibers present in the wet laid products are:
 a. within a range of 0.75 wt. % to 20 wt. %, based on weight percent of all fibers in the wet laid products, or alternatively, based on the weight of CE staple fibers and cellulose fibers in the wet laid products, or   b. the weight ratio of cellulose fibers to CE staple fibers is at least 3:1.   
     
     
         11 . Paperboard comprising cellulose fibers and cellulose ester (CE) staple fibers, said CE staple fibers having:
 i. a denier per filament (DPF) of less than 3, or   ii. a cut length of less than 6 mm, or   iii. crimping, or   iv. a combination of any two or more of (i)-(iv); and   wherein the paperboard has:
 a) a higher thickness relative to the same paperboard obtained from a 100% cellulose comparative composition, or 
 b) a lower density relative to the same paperboard obtained from a 100% cellulose comparative composition, or 
 c) a basis weight of at least 80 g/m 2 . 
   
     
     
         12 . Paperboard obtained from a composition comprising co-refined cellulose fibers and cellulose ester (CE) staple fibers, wherein the paperboard has the same, higher, or not more than a 5% reduction in Gurley stiffness, and a lower density, in each case relative to the same paperboard obtained from a 100% cellulose comparative composition. 
     
     
         13 . A process for light-weighting a wet laid product made in a wet laid process, comprising:
 a. making a first wet laid product with a first composition, said first wet laid product having a basis weight and a first thickness,   b. making a second wet laid product with a second composition, said second wet laid product having a second basis weight and a second thickness, said second composition comprising cellulose fibers and cellulose ester (CE) staple fibers,   wherein the second basis weight is less than the first basis weight, and the second thickness is within +/−5% of the first thickness.   
     
     
         14 . The process of  claim 13 , comprising:
 a. making a first paperboard with a first composition, said first paperboard having a first density and a first stiffness,   b. making a second paperboard with a second composition, said second paperboard having a second density and a second stiffness, said second composition comprising cellulose fibers and cellulose ester (CE) staple fibers,
 wherein the second paperboard has both a lower density relative to the first paperboard and the same, higher, or not more than a 5% reduction in Gurley stiffness relative to the first paperboard. 
   
     
     
         15 . The process of  claim 14 , comprising:
 a. making a first wet laid product with a first composition, said first wet laid product having a first basis weight and a first thickness and a first Gurley stiffness,   b. making a second wet laid product with a second composition, said second wet laid product having a second basis weight and a second thickness and a second Gurley stiffness, said second composition comprising cellulose fibers and cellulose ester (CE) staple fibers,   wherein the second basis weight is less than the first basis weight, and the second thickness does not drop below 5%, or is within +/−5% of the first thickness, or is thicker than the first thickness, and the second Gurley stiffness is the same as, higher, or reduced by not more than 5% of the first Gurley stiffness, and the CE staple fibers have:
 i. a denier per filament (DPF) of less than 3, or 
 ii. a cut length of less than 6 mm, or 
 iii. crimping, or 
 iv. a combination of any two or more of (i)-(iv). 
   
     
     
         16 . The process of  claim 13 , wherein the air permeability of the second wet laid product is maintained or increased, relative the air permeability of the first wet laid product. 
     
     
         17 . The process of  claim 13 , wherein said wet laid products comprise paperboard having a basis weight of at least 100 g/m2. 
     
     
         18 . The process of  claim 13 , wherein said wet laid product is packaging/container board or paperboard, or Kraft paper. 
     
     
         19 . The process of  claim 13 , wherein the cellulose fibers comprise waste/recycle cellulose fibers in an amount of at least 25 wt. %, based on the weight of all cellulose fibers present in the wet laid product. 
     
     
         20 . The process of  claim 13 , wherein the CE staple fibers are co-refined.