# US 10,501,890 B2 · Flexible microfibrillated film formation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,890 B2 - Document ID: US10501890B2 - Status: Granted - Kind: B2 - Application number: 15/754,692 - Filed: 2016-09-16 - Published: 2018-08-30 - Granted: 2019-12-10 - Earliest claimed: 2015-09-17 - Assignees: Stora Enso OYJ - Applicants: Stora Enso OYJ - Inventors: Isto Heiskanen; Kaj Backfolk; Katja Lyytikainen - Web page: https://patentgrep.com/patent/US10501890B2 ## CPC - D21H 11/18: Highly hydrated, swollen or fibrillatable fibres - D21H 27/30: Multi-ply (for surface covering D21H27/18; making on paper-making machines D21F9/00, D21F11/00) - 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 ## Abstract A method of manufacturing a film comprising microfibrillated cellulose, wherein the method comprises the steps of: providing a first suspension comprising microfibrillated cellulose, having a dry content of from 0.2 to 2.0%, wherein the first suspension has a first Schopper-Riegler (SR) value; forming a first web of said suspension; at least partly dewatering said first web; applying a second suspension comprising microfibrillated cellulose, and/or fines and/or fibers onto a surface of said formed and at least partially dried first web, wherein the second suspension has a second Schopper-Riegler value which is higher than said first Schopper-Riegler value, thereby forming a film. ## Claims ### Claim 1 A method of manufacturing a film comprising microfibrillated cellulose, wherein the method comprises the steps of: providing a first suspension comprising microfibrillated cellulose in an amount of at least 50 weight % based on the total weight of solids of the suspension, having a dry content of from 0.2 to 2.0%, wherein the first suspension has a first Schopper-Riegler (SR) value; forming a first web of said suspension; at least partly dewatering said first web; applying a second suspension comprising microfibrillated cellulose onto a surface of said formed and at least partially dewatered first web, wherein the second suspension has a second Schopper-Riegler value which is higher than said first Schopper-Riegler value; and, forming a film after the second suspension has been applied to said formed and at least partially dewatered first web. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein said first suspension further comprises a filler material in an amount of from 3 to 40 weight %, based on the total weight of solids of the suspension. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein said first suspension further comprises fibers in an amount from 5-50 weight %, based on the total weight of solids of the suspension. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein said first suspension has a SR value in the range of from 40 to 90. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein said second suspension further comprises at least one from a group consisting of: fines, fibers, fillers materials, retention chemicals, flocculation additives, deflocculating additives, wet strength chemicals, dry strength additives, softeners, or mixtures thereof. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein said second suspension is provided to the surface of the first web in a head-box. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein said second suspension is provided to the surface of the first web by a size press. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein said second SR value is from 5% to 30% higher than said first SR value. ### Claim 9 (depends on 1) The method as claimed in claim 1, wherein said second suspension has less dry content than the first suspension. ### Claim 10 (depends on 1) The method as claimed in claim 1, wherein said second suspension is applied to the surface of the first web in the form of foam. ### Claim 11 (depends on 1) The method as claimed in claim 1, wherein the method further comprises the step of dewatering the formed film. ### Claim 12 (depends on 11) The method as claimed in claim 11, wherein the dewatering is performed by vacuum. ### Claim 13 (depends on 11) The method as claimed claim 11, wherein the dewatering is performed by mechanical pressure. ### Claim 14 (depends on 1) A film obtained by the method as claimed in claim 1, wherein the film has an oxygen transmission rate (OTR) of less than 500 ml/m2/24 h. ### Claim 15 (depends on 1) A film obtained by the method as claimed in claim 1, wherein the film has a basis weight of less than 50 g/m2. ### Claim 16 (depends on 1) The method as claimed in claim 1, wherein said first suspension further comprises a filler material in an amount of from 5 to 15 weight %, based on the total weight of solids of the suspension. ### Claim 17 (depends on 1) The method as claimed in claim 1, wherein said first suspension further comprises long fibers in an amount of from 5 to 15 weight %, based on the total weight of solids of the suspension. ### Claim 18 (depends on 1) The method as claimed in claim 1, wherein said first suspension has a SR value in the range of from 60 to 85. ### Claim 19 (depends on 1) A film obtained by the method as claimed in claim 1, wherein the film has an oxygen transmission rate (OTR) of less than 50 ml/m2/24 h. ### Claim 20 (depends on 1) A film obtained by the method as claimed in claim 1, wherein the film has an oxygen transmission rate (OTR) of less than 1 ml/m2/24 h. ### Claim 21 (depends on 1) A film obtained by the method as claimed in claim 1, wherein the film has a basis weight of less than 35 g/m2. ### Claim 22 (depends on 1) A film obtained by the method as claimed in claim 1, wherein the film has a basis weight of less than 20 g/m2.