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US-12618199-B2 - Method for obtaining reinforced packaging paper

US12618199B2US 12618199 B2US12618199 B2US 12618199B2US-12618199-B2

Abstract

A method for obtaining a reinforced packaging paper includes applying a residual liquor from the pretreatment of lignocellulosic waste with a water-alcohol mixture to a packaging paper and subsequently drying the paper. The residual liquor has a solid fraction in suspension of 1-70% by weight/volume relative to the total, with lignin and lignin-carbohydrate complexes. The liquor also has a liquid fraction of 30-99% by weight/volume relative to the total, containing glucose between 0.04 and 2.07 g/L, xylose between 0.31 and 14.57 g/L, arabinose between 0.09 and 3.46 g/L, acetic acid between 0.083 and 12.40 g/L, and furfural between 0.004 and 8.73 g/L.

Inventors

  • Nuria GOMEZ HERNANDEZ
  • Priscilla Valeska VERGARA ALARCON
  • JUAN CARLOS VILLAR GUTIERREZ

Assignees

  • CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS (CSIC)

Dates

Publication Date
20260505
Application Date
20211027
Priority Date
20201218

Claims (14)

  1. 1 . A procedure for obtaining a reinforced packaging paper comprising: a) applying a residual liquor obtained from alcohol-water pretreatment of lignocellulosic residues on a packaging paper, wherein said residual liquor comprises: a solid fraction in suspension of 1-70% by weight/volume with respect to the total, comprising lignin and lignin-carbohydrate complexes and no sulphur degradation compounds; and a liquid fraction of 30-99% by weight/volume with respect to the total, containing glucose between 0.04 and 2.07 g/L, xylose between 0.31 and 14.57 g/L, arabinose between 0.09 and 3.46 g/L, acetic acid between 0.083 and 12.40 g/L, furfural between 0.004 and 8.73 g/L and b) drying the packaging paper obtained in step a), to obtain the reinforced packaging paper; wherein, prior to step a), the pretreatment of lignocellulosic residues comprises the steps of: (i) pretreating the lignocellulosic residues in a mixture of alcohol and water in the presence of an acid that acts as a catalyst to obtain a liquor and the solid pre-treated residues; (ii) separating the liquor of (i) from the solid pre-treated residues; and (iii) concentrating the liquor of (ii) to recover the alcohol and to obtain the residual liquor applied in step a).
  2. 2 . The procedure according to claim 1 , wherein the alcohol-water pretreatment is an ethanol-water pretreatment.
  3. 3 . The procedure according to claim 1 , wherein the glucose concentration is between 0.37 and 2.07 g/L.
  4. 4 . The procedure according to claim 3 , wherein the glucose concentration is between 0.37 and 0.62 g/L.
  5. 5 . The procedure according to claim 1 , wherein the xylose concentration is between 3 and 14.57 g/L.
  6. 6 . The procedure according to claim 5 , wherein the xylose concentration is between 3 and 4.37 g/L.
  7. 7 . The procedure according to claim 5 , wherein the xylose concentration is between 3.41 and 4.37 g/L.
  8. 8 . The procedure according to claim 1 , wherein the suspended solid fraction contains solids in a percentage between 1 and 10% with respect to the total weight of the residual liquor.
  9. 9 . The procedure according to claim 1 , wherein the application in step a) is between 4 and 34 g/m 2 of residual liquor.
  10. 10 . The procedure according to claim 9 , wherein the application in step a) is between 5 and 30 g/m 2 of residual liquor.
  11. 11 . The procedure according to claim 9 , wherein the application in step a) is between 15-25 g/m 2 , with a residual liquor containing between 1 and 3% solids in suspension.
  12. 12 . The procedure according to claim 11 , wherein the application in step a) is 20 g/m 2 , with a residual liquor containing 1% solids in suspension.
  13. 13 . The procedure according to claim 9 , wherein the application in step a) is between 20-30 g/m 2 with residual liquor containing between 3 and 10% suspended solids.
  14. 14 . The procedure according to claim 13 , wherein the application in step a) is between 20-30 g/m 2 with a residual liquor containing 5% suspended solids.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a 371 of PCT/ES2021/070778, filed Oct. 27, 2021, which claims the benefit of Spanish Patent Application No. P202031267, filed Dec. 18, 2020, each of which are incorporated herein by reference. TECHNICAL SECTOR The present invention corresponds to the paper industry sector, specifically in the manufacture of packaging paper. BACKGROUND OF THE INVENTION The main functions of packaging and packaging paper are to protect the product and absorb the stresses generated during its commissioning. Therefore, the main requirement for these papers is mechanical resistance. Component papers for corrugated cardboard represent the largest percentage of all papers produced in the packaging and packaging sector. This is because it is capable of withstanding high mechanical stress, which allows for great versatility and many other advantages over other materials, such as a very favorable utility/price ratio and sustainability. The current technique tends to reduce the grammage of the paper that constitutes the corrugated cardboard container. In this way, lighter boxes are obtained, reducing the amount of waste generated. However, this negatively affects the mechanical resistance of the paper, which is proportional to the grammage—that is, to the amount of fiber that makes it up. Therefore, it is necessary to develop strategies that provide resistance to the paper with a lower amount of fiber and keep its performance intact. In the case of papers made from recycled fibers the problem of lack of resistance in low grammage papers is even more serious because the resistance gradually decreases with the number of recycling cycles of the fibers. To increase resistance, some attempts have been made by adding synthetic polymers of fossil origin or chemicals. The most common additives are starch, polyacrylamides, alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA) and polyvinyl alcohol (PVA). However, petroleum derivatives come from non-renewable sources and present environmental problems that need to be avoided. An alternative to the petroleum-based chemicals used to increase the resistance of paper is the addition of bio-products of lignocellulosic origin to the fiber suspension with which the paper sheet is made or to the finished fibrous product. In this sense, the use of nanocrystalline cellulose (NCC) or nanofibrillated cellulose (NFC) mixed with a wide range of paper pulp has been tested. This combination is capable of obtaining interesting increases in tensile strength and compressive strength index (SCT), although the doses in which they must be incorporated make them unsuitable for an industrial process. The addition of other compounds such as hemicelluloses (xylan and arabinogalactan and galactoglucomannans) obtained from the treatment of lignocellulosic matter requires additional steps in the process, which increase costs. Other processes directly incorporate lignin or a lignin derivative. Previously, a lignin suspension together with other additives that aim to improve resistance or facilitate the application of lignin. Kopacic added precipitated lignin (lignosulfonates and Kraft lignin) to the surface of paper and board with subsequent heat treatment to achieve 10-20% compressive strength (SCT) improvements (Kopacic, S. et al. “Technical Lignins and Their Utilization in the Surface Sizing of Paperboard”; (2018) Industrial & Engineering Chemistry Research). Zhongming incorporated methacryloxyethyltimethylammonium chloride (DMC), acrylic acid (AA) and acrylamide (AM) monomers into Kraft lignins from pine pastes to prepare different copolymers, which when added to the paste improved tensile strength and tearing of laboratory sheets by almost 50% (Zhongming, L. et al. “Preparation and Characterization of Softwood Kraft Lignin Copolymers as a Paper Strength Additive”. (2018) Polymers 10(7):743). Patent AU2018202592 B2 improves the water resistance of paper and cardboard by preparing a total or partial solution of solid lignin in an alkaline solvent such as ammonia with which the paper is coated (Size-Press treatment). Subsequently, a heat or acid treatment is carried out. US2002084045 (A1) treats paper with a composition made from a lignin derivative and an organic solvent such as alcohol. This mixture can be applied in a very diverse way. WO2006027632 (A2) describes a method of surface treatment of paper using a mixture of solid lignin (lignosulfonate) with starch for treatment in Size-Press, or the use of lignosulfonate sprayed on the surface of the paper. CN102182112 (B) describes a process that includes the production of ethanol paste, to obtain a solution of hydroxymethyl-lignin to which acrylamide is added. Apart from the fact that the improvements in the mechanical resistance properties of these processes are limited, it must be noted that the solid lignin is predominantly in the form of lignosulphates. This implies that a sulfur compound is being adde