Expansion agents for paper-based materials

Abstract

Compositions and methods of producing paper-based materials are disclosed. The techniques can utilize an amine-containing polymer, such as chitosan, to functionalize one or more components of a mixture used to form materials such as paper-based materials. Such components can include the fibers of a pulp and/or filler particles. Techniques and compositions are also described to further improve the qualities of a paper material by utilizing a complementary polymer which can couple with the amine-containing polymer. Other compositions and methods are directed to forming paper-based materials that are expandable.

1 . An expandable paper product, comprising:
 paper pulp comprising fibers;   a plurality of expansion particles configured to increase the volume of the expanded paper product; and   a plurality of linker agents configured to be attached to the plurality of expansion particles, and to interact with the fibers to increase retention of the plurality of expansion particles in the expanded paper product.   
     
     
         2 . The expandable paper product of  claim 1 , wherein the expansion particles comprise at least one of blowing agents, encapsulated propellants, and elastomer-based particles. 
     
     
         3 . The expandable paper product of  claim 2 , wherein the expansion particles are encapsulated propellants, the encapsulated propellants comprising a polymeric shell encapsulating an expandable material. 
     
     
         4 . The expandable paper product of  claim 1 , wherein the expansion particles comprise hydrophobic particles. 
     
     
         5 . The expandable paper product of  claim 1 , wherein the plurality of linker agents impart a net positive charge to a surface of the plurality of expansion particles. 
     
     
         6 . The expandable paper product of  claim 1 , wherein the fibers exhibit a net negative charge. 
     
     
         7 . The expandable paper product of  claim 1 , wherein the plurality of linker agents comprise at least one of a coupling agent, a crosslinking agent, and a polymer. 
     
     
         8 . The expandable paper product of  claim 7 , wherein the plurality of linker agents are polymers, the polymers comprising at least one of a cationic polymer, a polymer exhibiting lower critical solution temperature behavior, a pH sensitive polymer, and an amphiphilic polymer. 
     
     
         9 . The expandable paper product of  claim 8 , wherein the polymers are amine-containing polymers. 
     
     
         10 . The expandable paper product of  claim 9 , wherein the amine-containing polymers comprise at least one of polyetheramine, chitosan, polyvinyl amine, polyalkyleneimine, polyallyl amine, and polydiallyl amine. 
     
     
         11 . The expandable paper product of  claim 7 , wherein the crosslinking agent comprises functional groups, the functional groups comprising at least one of an aldehyde, an isocyanate, and an epoxide. 
     
     
         12 . The expandable paper product of  claim 7 , wherein the coupling agent is a multifunctional silane coupling agent. 
     
     
         13 . The expandable paper product of  claim 1 , wherein the plurality of linker agents are covalently attached to the plurality of expansion particles. 
     
     
         14 . The expandable paper product of  claim 1 , wherein the plurality of linker agents are non-covalently attached to the plurality of expansion particles. 
     
     
         15 . A method for producing an expandable paper product, comprising:
 using a linker agent to attach expansion particles to fibers of a paper pulp to thereby increasing retention of the expansion particles; and   activating the expansion particles to produce the expandable paper product.   
     
     
         16 . The method of  claim 15 , wherein the step of activating the expansion particles comprises elevating the temperature of the expansion particles to cause an increase in volume in the expandable paper product. 
     
     
         17 . The method of  claim 15 , wherein the step of using the linker agent comprises using the linker agent to impart a net positive charge to a surface of at least a portion of the expansion particles. 
     
     
         18 . The method of  claim 17 , wherein the at least a portion of the expansion particles are attracted to a net negatively charged fiber in the paper pulp. 
     
     
         19 . The method of  claim 15 , wherein the step of using the linker agent comprises:
 introducing hydroxyl groups on a surface of the expansion particles; and   exposing the expansion particles to a silane-containing fluid, the silane-containing fluid attaching to at least a portion of the hydroxyl groups.   
     
     
         20 . The method of  claim 15 , wherein the step of using the linker agent comprises:
 providing a polymer exhibiting a lower critical solution temperature as the linker agent; and   contacting the expansion particles with the polymer at a high enough temperature to cause precipitation of the polymer onto a surface of the expansion particles.   
     
     
         21 . The method of  claim 15 , wherein the step of using the linker agent comprises:
 contacting the expansion particles with a polymer at a high enough pH to cause precipitation of the polymer onto a surface of the expansion particles.   
     
     
         22 . The method of  claim 15 , wherein the step of using the linker agent comprises:
 crosslinking the expansion particles with the fibers of the paper pulp.   
     
     
         23 . The method of  claim 15 , wherein the step of using the linker agent comprises:
 at least one of covalently attaching and non-covalently attaching the expansion particles to the linker agent.