Strengthened composite products and methods for making and using same

Abstract

The disclosure provides strengthened products, including strengthened fibrous composite products and methods for making and using same and strengthened particulates, such as particulate fertilizer products, and methods for making and using same. The fibrous composite product can include a plurality of fibers and an at least partially cured strengthening resin. The fertilizer composition can include a particulate core that can include a plant nutrient, at least one coating layer of the strengthening resin, and at least one coating layer of a water insoluble material. The strengthening resin can include one or more aldehyde-based resins and one or more crosslinked resins. The crosslinked resin can include one or more polyamines at least partially crosslinked by one or more symmetric crosslinks and can include one or more azetidinium functional groups.

What is claimed is: 
     
         1 . A fertilizer composition comprising:
 a particulate core comprising a plant nutrient;   at least one coating layer of a strengthening resin comprising an aldehyde-based resin and a crosslinked resin; and   at least one coating layer of a water insoluble material.   
     
     
         2 . The fertilizer composition of  claim 1 , wherein the aldehyde-based resin is a urea-formaldehyde resin. 
     
     
         3 . The fertilizer composition of  claim 1 , wherein the strengthening resin comprises the aldehyde-based resin blended with a crosslinked resin comprising a polyamidoamine backbone. 
     
     
         4 . The fertilizer composition of  claim 3 , wherein the crosslinked resin comprises a polyamidoamine-epihalohydrin. 
     
     
         5 . The fertilizer composition of  claim 1 , wherein the strengthening resin is present in an amount of about 1% to about 50% by weight relative to the weight of the plant nutrient core. 
     
     
         6 . The fertilizer composition of  claim 1 , wherein the strengthening resin is present in an amount of about 2% to about 15% by weight relative to the weight of the plant nutrient core. 
     
     
         7 . The fertilizer composition of  claim 1 , wherein the strengthening resin and the water insoluble material are present in a weight ratio of 1:5 to about 20:1. 
     
     
         8 . The fertilizer composition of  claim 1 , comprising at least two coating layers of the strengthening resin and at least one coating layer of the water insoluble material, and wherein the coating layers alternate. 
     
     
         9 . The fertilizer composition of  claim 1 , wherein the water insoluble material is selected from the group consisting of waxes, fatty acids, fatty acid esters, C9 or greater alcohols, and combinations thereof. 
     
     
         10 . The fertilizer composition of  claim 1 , comprising at least three coating layers of the strengthening resin. 
     
     
         11 . The fertilizer composition of  claim 1 , wherein the composition comprises the following layers in order from inner most to outer most:
 the particulate core comprising the plant nutrient;   at least one layer of the strengthening resin;   at least one layer of the water insoluble material;   at least one further layer of the strengthening resin; and   at least one further layer of the water insoluble material.   
     
     
         12 . The fertilizer composition of  claim 10 , further comprising a layer of the strengthening resin as the outer most layer. 
     
     
         13 . The fertilizer composition of  claim 1 , wherein the water insoluble material is present in an amount of about 0.01% to about 5° % by weight relative to the weight of the plant nutrient core. 
     
     
         14 . A method for making a fertilizer composition comprising:
 providing particles of a plant nutrient;   applying to the plant nutrient particles at least one coating layer of a strengthening resin comprising an aldehyde-based resin and a crosslinked resin;   optionally applying to the plant nutrient particles at least one coating layer of a water insoluble material; and   curing the fertilizer composition.   
     
     
         15 . The method of  claim 14 , comprising applying at least two coating layers of the strengthening resin and at least one coating layer of the water insoluble material. 
     
     
         16 . The method of  claim 15 , wherein the coating layers are applied in an alternating fashion. 
     
     
         17 . The method of  claim 14 , comprising applying at least three coating layers of the strengthening resin. 
     
     
         18 . The method of  claim 14 , comprising:
 applying to the plant nutrient particles at least one coating layer of the strengthening resin at a temperature of about 50° C. to about 200° C.;   curing the at least one coating layer of the strengthening resin at a temperature of about 50° C. to about 200° C. for a time of about 1 minute to about 20 minutes;   applying at least one coating layer of the water insoluble material; and   further curing the composition.   
     
     
         19 . A fibrous composite product, comprising:
 a plurality of fibers; and   an at least partially cured strengthening resin, wherein, prior to curing, the strengthening resin comprises about 85% to about 99.5% of an aldehyde-based resin and about 0.5% to about 15% of a crosslinked resin, based on a combined solids weight of the aldehyde based resin and the crosslinked resin,   wherein the crosslinked resin comprises a polyamine at least partially crosslinked by a symmetric crosslink and has azetidinium functional groups, and   wherein the fibrous composite product comprises about 10% to about 40% of the at least partially cured strengthening resin, based on a combined solids weight of the plurality of fibers and the at least partially cured strengthening resin.   
     
     
         20 . The fibrous composite product of  claim 19 , wherein the fibrous composite product is a fiber web and has an average dry tensile strength of about 38.6 kg/7.62 cm to about 90.7 kg/7.62 cm, as measured according to TAPPI/ANSI T 1009 om-10. 
     
     
         21 . The fibrous composite product of  claim 19 , wherein the polyamine at least partially crosslinked by the symmetric crosslink is also at least partially crosslinked by an epihalohydrin crosslink. 
     
     
         22 . The fibrous composite product of  claim 21 , wherein the symmetric crosslink is derived from N,N′-methylenebisacrylamide, and wherein the epihalohydrin crosslink is derived from epichlorohydrin. 
     
     
         23 . The fibrous composite product of  claim 19 , wherein the symmetric crosslink is derived from a compound selected from the group consisting of: a diacrylate, a bis(acrylamide), a bis(methacrylamide), a diepoxide, a polyazetidinium compound, a diisocyanate, a 1,3-dialkyldiazetidine-2,4-dione, a dianhydride, a diacyl halide, a dienone, a dialkyl halide, and a dialdehyde. 
     
     
         24 . The fibrous composite product of  claim 19 , wherein the fibrous composite product is a fiber web and has an average Elmendorf tear strength of about 400 gf to about 800 gf, as measured according to T 1006 sp-15. 
     
     
         25 . The fibrous composite product of  claim 19 , wherein the fibrous composite product has a basis weight of about 0.73 kg/9.29 m 2  to about 0.82 kg/9.29 m 2 . 
     
     
         26 . The fibrous composite product of  claim 19 , wherein the fibrous composite product comprises about 10% to about 25% of the at least partially cured strengthening resin, based on the combined solids weight of the plurality of fibers and the at least partially cured strengthening resin. 
     
     
         27 . The fibrous composite product of  claim 19 , wherein the crosslinked resin has a charge density of about 1 mEq/g of solids to about 4 mEq/g of solids. 
     
     
         28 . The fibrous composite product of  claim 19 , wherein the strengthening resin comprise about 90% to about 99.5% of the aldehyde-based resin, based on the combined solids weight of the aldehyde-based resin and the crosslinked resin. 
     
     
         29 . The fibrous composite product of  claim 19 , wherein the crosslinked resin comprises a reaction product of a crosslinked intermediate compound and an epihalohydrin, and wherein the crosslinked intermediate compound comprises a reaction product of a polyamidoamine and a bisacrylamide. 
     
     
         30 . The fibrous composite product of  claim 19 , wherein the aldehyde-based resin comprises a urea-formaldehyde resin, a phenol-formaldehyde resin, a resorcinol-formaldehyde resin, a phenol-resorcinol-formaldehyde resin, a phenol-urea-formaldehyde resin, a melamine-formaldehyde resin, a melamine-urea-formaldehyde resin, a phenol-melamine-formaldehyde resin, or any mixture thereof. 
     
     
         31 . The fibrous composite product of  claim 19 , wherein the plurality of fibers comprises glass fibers, mineral fibers, synthetic fibers, or any mixture thereof. 
     
     
         32 . A fibrous composite product, comprising:
 a fiber web; and   an at least partially cured strengthening resin, wherein prior to curing, the strengthening resin comprises about 85% to about 99.5% of a urea-formaldehyde resin and about 0.5% to about 15% of a crosslinked resin, based on a combined solids weight of the urea-formaldehyde resin and the crosslinked resin,   wherein the crosslinked resin comprises a polyamidoamine at least partially crosslinked by a symmetric crosslink and has azetidinium functional groups, and   wherein the fibrous composite product comprises about 10% to about 20% of the at least partially cured strengthening resin, based on a combined solids weight of the plurality of fibers and the at least partially cured strengthening resin.   
     
     
         33 . The fibrous composite product of  claim 32 , wherein the symmetric crosslink comprises a reaction product of the polyamidoamine and N,N′-methylenebisacrylamide. 
     
     
         34 . The fibrous composite product of  claim 33 , wherein the polyamidoamine at least partially crosslinked by the symmetric crosslink is also at least partially crosslinked by an epihalohydrin crosslink. 
     
     
         35 . A method for making a fibrous composite product, comprising:
 contacting a plurality of fibers with a strengthening resin, wherein the strengthening resin comprises about 85% to about 99.5% of an aldehyde-based resin and about 0.5% to about 15% of a crosslinked resin, based on a combined solids weight of the aldehyde-based resin and the crosslinked resin, and wherein the crosslinked resin comprises a polyamine at least partially crosslinked by a symmetric crosslink and has azetidinium functional groups; and   at least partially curing the strengthening resin in contact with the plurality of fibers to produce the fibrous composite product, wherein the fibrous composite product comprises about 10% to about 40% of the at least partially cured strengthening resin, based on a combined solids weight of the plurality of fibers and the at least partially cured strengthening resin.   
     
     
         36 . The method of  claim 35 , wherein the fibrous composite product is a fiber web and has at least one of: an average Elmendorf tear strength of about 400 gf to about 800 gf, as measured according to T 1006 sp-15, and an average dry tensile strength of about 38.6 kg/7.62 cm to about 90.7 kg/7.62 cm, as measured according to TAPPI/ANSI T 1009 om-10. 
     
     
         37 . The method of  claim 35 , wherein the strengthening resin in contact with the plurality of fibers is cured by heating the strengthening resin to a temperature of about 100° C. to about 350° C. for about 1 second to about 5 minutes. 
     
     
         38 . The method of  claim 35 , wherein the symmetric crosslink comprises a reaction product of the polyamine and N,N′-methylenebisacrylamide.