# US 5,707,491 A · Paper strengthened with solubilized collagen and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,707,491 A - Document ID: US5707491A - Status: Granted - Kind: A - Application number: 08/482,968 - Filed: 1995-06-07 - Granted: 1998-01-13 - Earliest claimed: 1993-06-16 - Assignees: Ranpak Corp. - Inventors: Kenneth E. Hughes; David C. Masterson; David J. Fink; Barbara A. Metz; Gordon E. Pickett; Paul M. Gemmer; Richard S. Brody - Web page: https://patentgrep.com/patent/US5707491A ## CPC - C07K 14/78: Connective tissue peptides, e.g. collagen, elastin, laminin, fibronectin, vitronectin or cold insoluble globulin [CIG] - D21H 17/22: Proteins - A61K 38/00: Medicinal preparations containing peptides (peptides containing beta-lactam rings A61K31/00; cyclic dipeptides not having in their molecule any other peptide link than those which form their ring, e.g. piperazine-2,5-diones, A61K31/00; ergot alkaloids of the cyclic peptide type A61K31/48; containing macromolecular compounds having statistically distributed amino acid units A61K31/74; medicinal preparations containing antigens or antibodies A61K39/00; medicinal preparations characterised by the non-active ingredients, e.g. peptides as drug carriers, A61K47/00) - D21H 11/14: Secondary fibres (working-up waste paper D21C5/02) - D21H 21/18: Reinforcing agents - C07K: PEPTIDES (peptides in foodstuffs A23; obtaining protein compositions for foodstuffs, working-up proteins for foodstuffs A23J; preparations for medicinal purposes A61K; peptides containing beta-lactam rings C07D; cyclic dipeptides not having in their molecule any other peptide link than those which form their ring, e.g. piperazine-2,5-diones, C07D; ergot alkaloids of the cyclic peptide type C07D519/02; macromolecular compounds having statistically distributed amino acid units in their molecules, i.e. when the preparation does not provide for a specific; but for a random sequence of the amino acid units, homopolyamides and block copolyamides derived from amino acids C08G69/00; macromolecular products derived from proteins C08H1/00; preparation of glue or gelatine C09H; single cell proteins, enzymes C12N; genetic engineering processes for obtaining peptides C12N15/00; compositions for measuring or testing processes involving enzymes C12Q; investigation or analysis of biological material G01N33/00) - D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR - A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D) ## Abstract A method for making a collagen strengthened cellulosic sheet by providing a cellulosic pulp slurry; adding solubilized collagen to the pulp slurry, and mixing for a time effective for interaction of the cellulosic pulp slurry and solubilized collagen; forming the interacted cellulosic pulp slurry and solubilized collagen into a sheet; and drying the sheet; also, a method for using solubilized collagen for strengthening paper by mixing the solubilized collagen with a cellulosic pulp slurry; and making a cellulosic pulp product from the mixture and drying. ## Claims ### Claim 1 A method for using soluble collagen in a paper-making process comprising the steps of: a. reacting insoluble collagen with a proteolytic enzyme to produce a solution including soluble collagen having a number average molecular weight of above about 300,000 daltons; b. withdrawing the soluble collagen as product; and c. using said soluble collagen in a paper-making process. ### Claim 2 (depends on 1) A method as set forth in claim 1, wherein said insoluble collagen is provided as an aqueous ground slurry. ### Claim 3 (depends on 2) A method as set forth in claim 2, further comprising adjusting the water or solid content of said slurry whereby said insoluble collagen is at a concentration that promotes substantially maximum soluble collagen concentration and molecular weight in a final product. ### Claim 4 (depends on 2) A method as set forth in claim 2, further comprising adjusting the pH of said slurry to obtain activity for a proteolytic enzyme, prior to reacting said insoluble collagen with said proteolytic enzyme. ### Claim 5 (depends on 1) A method as set forth in claim 1, further comprising controlling said reaction of Step a to obtain a high degree of conversion of insoluble collagen to soluble collagen and to maximize the molecular weight of said soluble collagen. ### Claim 6 (depends on 5) A method as set forth in claim 5, further comprising simultaneously measuring the concentration of soluble collagen and the molecular weight of said soluble collagen, whereby said reaction is complete when said molecular weight and said concentration are substantially maximized. ### Claim 7 (depends on 1) A method as set forth in claim 1, whereby said reaction of Step a is at a temperature, T, and a time, t, effective for forming a solution of soluble collagen from said insoluble collagen. ### Claim 8 (depends on 1) A method as set forth in claim 1, further comprising: after the soluble collagen is withdrawn as product, returning any remaining insoluble collagen to Step a, whereby at least a portion of the proteolytic enzyme is recycled. ### Claim 9 (depends on 1) A method as set forth in claim 1, further comprising: a. adding additional insoluble collagen, with or without the addition of water and/or additional proteolytic enzyme, to the solution of soluble collagen produced in step a, whereby the proteolytic enzyme reacts with the additional insoluble collagen to produce soluble collagen having a number average molecular weight of above about 300,000 daltons; b. separating at least some of the soluble collagen from the insoluble collagen; and c. returning the separated insoluble collagen to step a, whereby at least a portion of said proteolytic enzyme is recycled. ### Claim 10 (depends on 1) A method as set forth in claim 1, further comprising mixing the soluble collagen of Step b with a cellulosic pulp slurry. ### Claim 11 (depends on 10) A method as set forth in claim 10, wherein said cellulosic pulp slurry is prepared by a method comprising: a. mixing cellulosic material selected from the group consisting of virgin paper pulp, broke, reclaimed newsprint, reclaimed carton container, or a mixture thereof, with a solution comprising water, or water and caustic; and b. pulping said mixture until a cellulosic pulp slurry is formed having a consistency of about 3 wt % to about 6 wt % based on dry pulp solids. ### Claim 12 (depends on 11) A method as set forth in claim 11, further comprising diluting said cellulosic pulp slurry of Step b to a consistency of about 1 wt % to about 3 wt % based on dry pulp solids and adjusting pH to about 3.5 to about 7.0, prior to mixing with said soluble collagen. ### Claim 13 (depends on 10) A method as set forth in claim 10, wherein said mixing is at a shear rate and a time effective for interaction of said dilute pulp slurry and said soluble collagen, whereby at least a substantial portion of said soluble collagen is bound to said paper pulp to form a collagen/pulp slurry. ### Claim 14 (depends on 13) A method as set forth in claim 13, wherein said collagen/pulp slurry is further diluted to between about 0.1 dry wt % and 1 dry wt % consistency. ### Claim 15 (depends on 14) A method as set forth in claim 14, further comprising using said diluted collagen/pulp slurry to form a sheet and drying said sheet. ### Claim 16 (depends on 1) The method of claim 1 wherein the soluble collagen formed in step a has a number average molecular weight above 1,000,000 daltons.