Two-part sizing composition for reinforcement fibers

Abstract

A two-part sizing formulation that imparts improved strength of reinforced composites including a size composition and a binder composition is provided. The size composition may include one or more coupling agents and one or more film forming agents. The binder composition includes a high acid number copolymer formed from the polymerization of maleic anhydride or maleic acid and at least one other desired monomer and/or a high acid number polycarboxylic acid. In a preferred embodiment, the binder composition includes an ethylene-maleic acid copolymer formed by the hydrolysis of an ethylene-maleic anhydride copolymer. The size composition may be applied to a reinforcing fiber material before the binder size material is applied. The two-part size composition may be applied to a reinforcing fiber material to form a reinforcing fiber product which may then be densified or compacted to form a densified reinforcing fiber product, such as a pellet.

1 . A two-part sizing formulation for sizing a reinforcing fiber used to form a composite product when combined with a polymer that includes a di-cation or a higher valency cation, said two-part sizing formulation comprising: 
 a size composition; and    a binder composition including at least one high acid number polyacid containing acid moieties, said acid moieties being present in an amount that is greater than the amount of said di-cation or said higher valency cation present in said polymer.    
   
   
       2 . The two-part sizing formulation of  claim 1 , wherein said amount of said acid moieties is sufficient to retain at least a portion of said acid moieties after interacting with said di-cation or said higher valency cation when forming said composite material.  
   
   
       3 . The two-part sizing formulation of  claim 1 , wherein said at least one high acid number polyacid is present on said reinforcing fiber in an amount sufficient to provide a loss-on-ignition up to about 2.0%.  
   
   
       4 . The two-part sizing formulation of  claim 1 , wherein said at least one high acid number polyacid is a polyacid selected from a high acid number copolymer formed from the polymerization of maleic anhydride and at least one other monomer copolymerized therewith, a copolymer formed from the polymerization of maleic acid and at least one other monomer copolymerized therewith, and a high acid number polycarboxylic acid.  
   
   
       5 . The two-part sizing formulation of  claim 4 , wherein said at least one high acid number polyacid is an ethylene-maleic acid copolymer.  
   
   
       6 . The two-part sizing formulation of  claim 1 , wherein said high acid number is from about 300 to about 950.  
   
   
       7 . The two-part sizing formulation of  claim 1 , wherein said size composition comprises a coupling agent and a first film forming agent.  
   
   
       8 . The two-part sizing composition of  claim 1 , wherein said binder composition further comprises a second film forming agent, said first and second film forming agents being the same as or different from each other.  
   
   
       9 . The two part sizing formulation of  claim 8 , wherein at least one of said first and second film forming agents is a polyurethane film forming agent based on a non-blocked isocyanate.  
   
   
       10 . A two-part sizing formulation for sizing a reinforcing fiber used to form a composite material when combined with a polymer that includes a di-cation or a higher valency cation, said two-part sizing formulation comprising: 
 a size composition containing a first film former; and    a binder composition including at least one high acid number polyacid selected from a copolymer formed from the polymerization of maleic anhydride and at least one other monomer copolymerized therewith, a copolymer formed from the polymerization of maleic acid and at least one other monomer copolymerized therewith, and a high acid number polycarboxylic acid.    
   
   
       11 . The two-part sizing formulation of  claim 10 , wherein said at least one high acid number polyacid contains acid moieties, said acid moieties being present in an amount that is greater than the amount of said di-cation or said higher valency cation present in said polymer.  
   
   
       12 . The two-part sizing formulation of  claim 1   1 , wherein said high acid number is from about 300 to about 950.  
   
   
       13 . The two-part sizing formulation of  claim 10 , wherein said high acid number polyacid is present on said reinforcing fiber in an amount sufficient to provide a loss-on-ignition up to about 2.0%.  
   
   
       14 . The two-part sizing formulation of  claim 13 , wherein said binder composition further comprises a second film forming agent, said first and second film forming agents being the same as or different from each other.  
   
   
       15 . The two-part sizing formulation of  claim 14 , wherein at least one of said first and second film forming agents is a polyurethane film forming agent based on a non-blocked isocyanate.  
   
   
       16 . A reinforced composite product comprising: 
 a polymer matrix containing a di-cation or a higher valency cation; and    a plurality of strands of a reinforcing fiber, the strands including: 
 an inner coating of a size composition; and  
 an outer coating of a binder composition including at least one high acid number polyacid containing acid moieties, said acid moieties being present in an amount that is greater than the amount of said di-cation or said higher valency cation present in said polymer matrix.  
   
   
   
       17 . The reinforced composite product of  claim 16 , wherein said at least one high acid number polyacid is a polyacid selected from a copolymer formed from the polymerization of maleic anhydride and at least one other monomer copolymerized therewith, a copolymer formed from the polymerization of maleic acid and at least one other monomer copolymerized therewith, and a polycarboxylic acid.  
   
   
       18 . The reinforced composite product of  claim 17 , wherein said at least one high acid number polyacid is present on said reinforcing fiber in an amount sufficient to provide a loss-on-ignition up to about 2.0%.  
   
   
       19 . The reinforced composite product of  claim 18 , wherein said at least one high acid number polyacid is an ethylene-maleic acid copolymer.  
   
   
       20 . The reinforced composite product of  claim 16 , wherein said at least one high acid number is from about 300 to about 950.  
   
   
       21 . The reinforced composite product of  claim 16 , wherein said size composition comprises a first film forming agent.  
   
   
       22 . The reinforced composite product of  claim 21 , wherein said binder composition further comprises a second film forming agent, said second film forming agent being the same as or different from said first film forming agent.  
   
   
       23 . The reinforced composite product of  claim 22 , wherein at least one of said first and second film forming agents is a polyurethane film forming agent based on a non-blocked isocyanate.  
   
   
       24 . A sized reinforcing fiber used to form a composite product when combined with a polymer that includes a di-cation or a higher valency cation, said sized reinforcing fiber comprising: 
 a reinforcing fiber at least partially coated with a two-part sizing formulation, said two-part sizing formulation including: 
 a size composition; and  
 a binder composition including at least one high acid number polyacid containing acid moieties, said acid moieties being present in an amount that is greater than the amount of said di-cation or said higher valency cation present in said polymer.  
   
   
   
       25 . The sized reinforcing fiber of  claim 24 , wherein said amount of said acid moieties is sufficient to retain at least a portion of said acid moieties after interacting with said di-cation or said higher valency cation when forming said composite material.  
   
   
       26 . The sized reinforcing fiber of  claim 24 , wherein said at least one high acid number polyacid is present on said reinforcing fiber in an amount sufficient to provide a loss-on-ignition up to about 2.0%.  
   
   
       27 . The sized reinforcing fiber of  claim 24 , wherein said high acid number is from about 300 to about 950.  
   
   
       28 . The sized reinforcing fiber of  claim 24 , wherein said size composition comprises a coupling agent and a first film forming agent.  
   
   
       29 . The sized reinforcing fiber of  claim 28 , wherein said binder composition further comprises a second film forming agent, said first and second film forming agents being the same as or different from each other.  
   
   
       30 . The sized reinforcing fiber of  claim 28 , wherein at least one of said first and second film forming agents is a polyurethane film forming agent based on a non-blocked isocyanate.  
   
   
       31 . The sized reinforcing fiber of  claim 24 , wherein said at least one high acid number polyacid is a polyacid selected from a high acid number copolymer formed from the polymerization of maleic anhydride and at least one other monomer copolymerized therewith, a copolymer formed from the polymerization of maleic acid and at least one other monomer copolymerized therewith, and a high acid number polycarboxylic acid.  
   
   
       32 . A sized reinforcing fiber comprising: 
 a reinforcing fiber at least partially coated with a two-part sizing formulation, said two-part sizing formulation including: 
 a size composition containing a first film former; and  
 a binder composition including at least one high acid number polyacid selected from a copolymer formed from the polymerization of maleic anhydride and at least one other monomer copolymerized therewith, a copolymer formed from the polymerization of maleic acid and at least one other monomer copolymerized therewith, and a high acid number polycarboxylic acid.  
   
   
   
       33 . The sized reinforcing fiber of  claim 32 , wherein said high acid number is from about 300 to about 950.  
   
   
       34 . The sized reinforcing fiber of  claim 32 , wherein said high acid number polyacid is present on said reinforcing fiber in an amount sufficient to provide a loss-on-ignition up to about 2.0%.  
   
   
       35 . The sized reinforcing fiber of  claim 32 , wherein said binder composition further comprises a second film forming agent, said first and second film forming agents being the same as or different from each other.  
   
   
       36 . The sized reinforcing fiber of  claim 32 , wherein at least one of said first and second film forming agents is a polyurethane film forming agent based on a non-blocked isocyanate.  
   
   
       37 . A method of preparing a sized reinforcing fiber for reinforcing a composite article that contains a di-cation or higher valency cation comprising: 
 applying a size composition to at least a portion of a reinforcing fiber to form a coated reinforced fiber material; and    applying a binder composition to said coated reinforced fiber material, said binder composition including at least one high acid number polyacid containing acid moieties, said acid moieties being present in an amount that is greater than the amount of said di-cation or said higher valency cation in said composite article.    
   
   
       38 . The method of  claim 37 , wherein said size composition comprises a film forming agent.  
   
   
       39 . The method of  claim 38 , wherein said amount of said acid moieties is sufficient to retain at least a portion of said acid moieties after interacting with said di-cation or said higher valency cation.  
   
   
       40 . The method of  claim 37 , wherein said at least one high acid number polyacid is present on said reinforcing fiber in an amount sufficient to provide a loss-on-ignition up to about 2.0%.  
   
   
       41 . A method of forming reinforcing fiber pellets comprising: 
 at least partially coating reinforcing fibers with a size composition to form coated reinforcing fibers, said size composition including a first film forming agent;    chopping the coated reinforcing fibers to produce reduced length coated reinforcing fibers;    at least partially coating said reduced length coated reinforcement fibers with a binder composition to form binder-coated reduced length reinforcement fibers, said binder composition including at least one high acid number polyacid selected from a copolymer formed from the polymerization of maleic anhydride and at least one other monomer copolymerized therewith, a copolymer formed from the polymerization of maleic acid and at least one other monomer copolymerized therewith, and a high acid number polycarboxylic acid; and    pelletizing the binder-coated reduced length reinforcement fibers to form reinforcing fiber pellets.    
   
   
       42 . The method of  claim 41 , further comprising: 
 densifying said reinforcing fiber pellets.    
   
   
       43 . The method of  claim 42 , wherein said at least one high acid number polyacid is present on said binder-coated reduced length reinforcement fibers in an amount sufficient to provide a loss-on-ignition up to about 2.0%.  
   
   
       44 . The method of  claim 43 , wherein said binder composition further comprises a second film forming agent, said first and second film forming agents being the same as or different from each other.  
   
   
       45 . The sized reinforcing fiber of  claim 44 , wherein at least one of said first and second film forming agents is a polyurethane film forming agent based on a non-blocked isocyanate.