# US 8,465,581 B2 · Stable acid denatured soy/urea adhesives and methods of making same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,581 B2 - Document ID: US8465581B2 - Status: Granted - Kind: B2 - Application number: 12/869,848 - Filed: 2010-08-27 - Published: 2011-03-03 - Granted: 2013-06-18 - Earliest claimed: 2009-08-28 - Assignees: Hercules Incorporated - Applicants: James M. Wescott; Michael J. Birkeland - Inventors: James M. Wescott; Michael J. Birkeland - Web page: https://patentgrep.com/patent/US8465581B2 ## CPC - C09J 189/00: Adhesives based on proteins; Adhesives based on derivatives thereof - C08L 23/0853: Ethylene vinyl acetate copolymers - C08L 2666/02: Organic macromolecular compounds, natural resins, waxes or and bituminous materials - C08L 2666/06: Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof - C08L 2666/20: Macromolecular compounds having nitrogen in the main chain according to C08L75/00 - C08L79/00; Derivatives thereof - C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) ## Abstract The present invention provides an improved method of producing a stable acid denatured soy/urea adhesive having improved wet and dry strengths, with more efficient production and lower production costs. The method comprises combining urea with soy flour that has been acid treated until denatured and substantially free from urease activity. The soy flour is preferably lowered to a pH of 2.0 to 4.0 for at least 1 minute. Optionally, the method may also include adding a crosslinking agent, diluent or both to the soy flour/urea adhesive and/or adding an emulsified or dispersed polymer. Adhesives and dispersions prepared according to the methods of this invention offer increased stability and strength properties. ## Claims ### Claim 1 A stable adhesive composition comprised of urea and soy flour in water wherein the urease present in the soy flour has been deactivated by an acid treatment, wherein the acid treatment comprises lowering the pH of the dispersed soy flour to less than 4.5 and greater than 2.0 for a period of at least 1 minute prior to combining it with urea; wherein the urea is present in the composition in an amount equivalent to at most five pails urea by weight for every one part by weight soy flour. ### Claim 2 (depends on 1) The composition of claim 1 further comprising a crosslinking agent. ### Claim 3 (depends on 2) The composition of claim 2 wherein the amount of the crosslinking agent in the composition is 0.1 to 80% solids based on the dry weight of total adhesive. ### Claim 4 (depends on 2) The composition of claim 2 wherein the crosslinking agent comprises a formaldehyde-free crosslinking agent selected from the group consisting of isocyanate, polyamine epichlorohydrin resin, polyamidoamine-epichlorohydrin resin, polyalkylene polyamine-epichlorohydrin, amine polymer-epichlorohydrin resin epoxy, aldehyde, aldehyde starch, dialdehyde starch, glyoxal, urea glyoxal, urea-aldehyde resin and mixtures thereof. ### Claim 5 (depends on 2) The composition of claim 2 wherein the crosslinking agent comprises an isocyanate. ### Claim 6 (depends on 2) The composition of claim 2 wherein the crosslinking agent comprises a polyamidoamine-epichlorohydrin resin. ### Claim 7 (depends on 2) The composition of claim 2 wherein the crosslinking agent comprises a formaldehyde-containing crosslinking agent selected from the group consisting of formaldehyde, phenol formaldehyde, melamine formaldehyde, urea formaldehyde, melamine urea formaldehyde, phenol resorcinol formaldehyde and any combination thereof. ### Claim 8 (depends on 1) The composition of claim 1 further comprising an emulsion polymer. ### Claim 9 (depends on 8) The composition of claim 8 wherein the amount of the emulsion polymer in the composition is from 0.1 to 80% by dry weight based on the dry weight of total adhesive. ### Claim 10 (depends on 8) The composition of claim 8 wherein the emulsion polymer comprises a polyvinyl acetate (PVAc). ### Claim 11 (depends on 1) The composition of claim 1 further comprising a diluent. ### Claim 12 (depends on 1) The composition of claim 1, wherein the diluent is selected from the group consisting of glycerol, ethylene glycol, propylene glycol, neopentyl glycol and polymeric versions thereof. ### Claim 13 (depends on 1) A method of making the stable adhesive of claim 1, the method comprising the steps of a) dispersing soy flour in water b) lowering the pH of the dispersed soy flour to at least 4.5, but greater than 2.0 for a period of at least 1 minute to deactivate the urease, c) contacting the dispersed soy flour with urea, and wherein the urea is added to the soy flour in an amount equivalent to at most five parts urea for every one part soy flour. ### Claim 14 (depends on 13) The method of claim 13 wherein the urea is added to the soy flour after the soy flour is substantially free of urease. ### Claim 15 (depends on 13) The method of claim 13 further comprising the step of adding an emulsion polymer. ### Claim 16 (depends on 13) The method of claim 13 wherein the amount of the emulsion polymer added is from 0.1 to 80% by dry weight based on the dry weight of total adhesive. ### Claim 17 (depends on 13) The method of claim 13 further comprising the step of adding a diluent. ### Claim 18 (depends on 13) The method of claim 13 further comprising the step of adding a crosslinking agent.