Method for manufacturing a cellulose fiber-based article and cellulose fiber-based article manufactured thereby

Abstract

The present invention relates to a manufacturing method of a cellulose fiber-based article and a cellulose fiber-based article manufactured thereby. The manufacturing method 10 essentially comprises the following steps: mixing 12 a dry substance with water, wherein the dry substance comprises at least between 80% to 99%, preferably between 90% to 99%, of cellulose fibers, and between 1% to 20%, preferably between 1% to 10%, of a water-soluble polymer or water-retention additive, preferably natural, to obtain a cellulose fiber-based slurry having a dry substance concentration essentially between 10% to 70%, preferably between 20% to 50%, by weight; shaping 14 the slurry in a mold of the article to be manufactured without drying; and drying 16 the slurry shaped in the mold by heat compression.

Description

Technical Field

[0001] This invention relates to the manufacture of cellulose fiber-based articles, particularly three-dimensional articles. More specifically, this invention relates to a method for manufacturing cellulose fiber-based articles and the cellulose fiber-based articles thus manufactured. Background Technology

[0002] In response to environmental problems and the proliferation of plastic packaging waste, new regulations are being introduced globally for single-use packaging, particularly in Europe, where a European directive on the subject came into effect in 2018.

[0003] Therefore, new solutions are needed to replace plastics, and these solutions must not only be equally efficient but also recyclable, biomass-derived, and biodegradable. Only cellulose possesses all three of these characteristics. However, progress is still needed in the molding and performance of cellulose materials. For example, complex lids, tableware, or containers are currently manufactured using plastic injection molding processes; this invention aims to provide a cellulose fiber-based alternative.

[0004] Cellulose fibers are widely used in the packaging industry. Besides paper and paperboard, a wet molding process for cellulose, which has existed for many years, uses a highly diluted fiber suspension (0.1-1 wt%). This process requires a compression / sucking step to remove some of the moisture from the fiber padding. In addition, a dry molding process has emerged in recent years, which can create simple three-dimensional articles from a roll of paper using airflow forming. However, like the molded cellulose process, complex shapes requiring right angles, closed angles, or solid objects cannot be achieved using these cellulose-based processes. Furthermore, articles produced using dry molding cellulose currently cannot exceed 3 cm in depth.

[0005] Companies like Nissha® or Paperfoam® offer cellulose injection molding solutions, which are essentially cellulose composites containing 20% ​​to 60% cellulose, along with a polymer matrix such as starch or polyvinyl alcohol (PVOH) and various additives.

[0006] There is an urgent need for cellulose fiber-based packaging products that are recyclable, reusable, biodegradable, and manufactured in a more environmentally friendly manner. This invention aims to at least partially meet this need. Summary of the Invention

[0007] To achieve this goal, according to a first aspect of the present invention, a method for manufacturing an article based on cellulose fibers is provided, comprising the following steps: - A dry matter is mixed with water, the dry matter comprising at least 80% to 99%, preferably 90% to 99% cellulose fibers, and 1% to 20%, preferably 1% to 10% water-soluble polymer (preferably natural and cold-soluble, more preferably long-chain) or water-retaining polymer, to obtain a cellulose fiber-based slurry having a dry matter concentration substantially between 10% and 70% by weight, preferably between 20% and 50%, more preferably between 20% and 30%; - Without drying, the slurry is molded into a 2D or 3D shape in a mold for the item to be manufactured. - The slurry formed in the mold is dried by thermal compression.

[0008] According to a second aspect of the invention, an article based on cellulose fibers is provided, comprising or consisting of the following components: - Cellulose fibers with a dry matter concentration of 80% to 99% by weight, preferably between 90% and 99%, and - A water-soluble polymer (preferably natural and cold-soluble, more preferably long-chain) or a water-retaining polymer and / or additives with a dry matter concentration of between 1% and 20% by weight, preferably between 1% and 10%.

[0009] Articles constructed according to the second aspect of the invention, for example, three-dimensional packaging, are advantageously free of starch and / or polyvinyl alcohol (PVOH). Attached Figure Description

[0010] The object, features, and advantages of the present invention will become clearer from a detailed description of one embodiment thereof, illustrated in the following figures, wherein: Figure 1 A flowchart of an embodiment of a manufacturing method according to the first aspect of the present invention is shown.

[0011] Figure 2 A cross-section of an embodiment of a cellulose fiber-based article according to a second aspect of the invention is schematically shown, the article being container-shaped, more specifically, yogurt jar-shaped.

[0012] The accompanying drawings are merely illustrative and do not limit the scope of the invention. They are schematic diagrams intended to facilitate understanding of the invention and are not necessarily drawn to scale for actual applications. Detailed Implementation

[0013] Before beginning a detailed review of the embodiments of the present invention, some optional features will be described below, which can be used in combination or individually: According to one embodiment of the first aspect of the invention, the mixing is carried out in a twin-screw extruder.

[0014] According to one embodiment of the first aspect of the present invention, the slurry molding step is performed at room temperature.

[0015] According to an embodiment of the first aspect of the invention, the dry matter to be mixed further comprises cellulose nanocrystals, nanofibrils, or microfibrils at a concentration between 0.01% and 50% by weight of the dry matter, preferably between 1% and 20%.

[0016] According to one embodiment of the first aspect of the invention, the dry matter to be mixed further comprises at least one surfactant-type foaming agent with a concentration between 0.01% and 10% by weight of the dry matter. Advantageously, the foaming agent makes the resulting article lighter, dries it faster, and stabilizes the dimensions of the article.

[0017] According to one embodiment of the first aspect of the present invention, the slurry forming step is performed by injection molding.

[0018] According to an alternative embodiment of the foregoing embodiments, the slurry forming step is performed by transfer molding.

[0019] According to one embodiment of the first aspect of the invention, the cellulose fibers to be mixed are derived from pulp.

[0020] According to the foregoing embodiments, the water-soluble polymer (preferably natural) or water-retaining additive may be selected from: - Cellulose ethers (HPMC, HEC, HPC, CMC) - Synthetic polymers (e.g., polyethylene glycol, polyvinyl alcohol). - Guar gum, carob gum, or xanthan gum, - Alginate, agar, carrageenan, - Pectin or hemicellulose, - Functionalized or unfunctionalized cellulose nanocrystals or nanofibers, and - A mixture of them.

[0021] According to one embodiment, at least one conventional additive used in the papermaking and molded cellulose fields may be added to the formulation, such additive being selected, for example, from: - Mineral fillers, - Hydrophobic additives, such as waxes, drying oils, or polymer emulsions. - Cellulose fiber functionalizing additives, such as AKD (alkyl ketene dimer), rosin resin or ASA (alkenyl succinic anhydride). - Wet strength agent, and - A mixture of them.

[0022] According to one embodiment of the first aspect of the invention, the thermal compression drying step is carried out at a temperature substantially between 100 and 200°C, preferably substantially between 120 and 180°C, and / or at a pressure substantially between 1 and 40 MPa.

[0023] According to one embodiment of the first aspect of the invention, the hot compression drying step is carried out using a hot press by opening and closing the hot press at least once, so that moisture is discharged in the form of water vapor.

[0024] According to alternative or supplementary embodiments of the foregoing embodiments, the hot compression drying step is carried out using a hot press having at least one perforated element, so that water is discharged in the form of steam through the perforation of the at least one element.

[0025] According to one embodiment of the first aspect of the present invention, the slurry to be formed does not contain starch and / or polyvinyl alcohol (PVOH).

[0026] A slurry based on material A should be understood as a slurry that includes material A and may include other materials.

[0027] For a parameter that is “substantially equal to / greater than / less than” a given value, it should be understood that the parameter is equal to / greater than / less than the given value, and the deviation from the value is within 20% or 10%. For a parameter that is “substantially between” two given values, it should be understood that the parameter is at least equal to the given lowest value (within 20% or 10% tolerance of that value) and at most equal to the given highest value (within 20% or 10% tolerance of that value).

[0028] The following reference Figure 1 The first aspect of the invention is described, which relates to a method 10 for manufacturing an article 1 based on cellulose fibers.

[0029] This method basically includes the following steps: - Mix dry matter with water 12, the dry matter comprising at least 80% to 99%, preferably 90% to 99% cellulose fibers, and 1% to 20%, preferably 1% to 10% water-soluble polymer (preferably natural polymer) or water-retaining additive, to obtain a cellulose fiber-based slurry having a dry matter concentration substantially between 10% and 70%, preferably between 20% and 50%, more preferably between 20% and 30% by weight. - Without drying, the slurry is molded in a mold for the article to be manufactured 14. - The slurry formed in the mold is dried by thermal compression 16.

[0030] The purpose of using preferred natural water-soluble polymers or water-retaining additives is to enable the slurry derived from Mixture 12 to be injection molded or transfer molded.

[0031] Mixing 12 is preferably carried out in a twin-screw extruder to ensure good uniformity of the slurry.

[0032] The slurry molding step 14 is advantageously carried out at room temperature (typically 20 to 30°C), thereby limiting the thermal balance during the manufacturing process.

[0033] The fiber network strength of the manufactured article 10 can be enhanced by adding cellulose nanocrystals, nanofibrils, or microfibrils at a concentration of 0.01% to 50% by dry matter weight to the dry matter to be mixed 12. More specifically, a cellulose nanofibril or microfibril slurry at a concentration of 0.01% to 50% by dry matter weight can be added at the inlet of a twin-screw extruder, for example, during the second pass of the slurry to be mixed 12 in the twin-screw extruder.

[0034] Alternatively, the dry matter to be mixed 12 may also contain at least one surfactant-type foaming agent at a concentration between 0.01% and 10% by weight of the dry matter. Advantageously, this foaming agent can make the produced articles lighter, dry them faster, and stabilize their dimensions.

[0035] The slurry forming step 14 can be performed by injection molding or transfer molding, i.e., by an injection molding system, similar to a twin-screw extruder, which is already present in industry. Injection molding or transfer molding of concentrated cellulose slurry can yield a wider range of articles compared to existing methods. In a non-limiting manner, the manufactured article 10 can, for example, constitute a pre-formed cellulose container, such as a plate or yogurt jar (see...). Figure 2 ); pre-formed cellulose tableware, such as flatware; and pre-formed cellulose stoppers, including threaded stoppers. More specifically, mixture 12 can be injected into a die at the exit of a twin-screw extruder, or subsequently via pass molding.

[0036] Advantageously, the cellulose fibers to be mixed 12 can be derived from pulp or any other cellulose source, particularly biological sources, such as various types of coniferous wood, hardwood, bleached or unbleached pulp, annual plant fibers such as flax, hemp, straw, and agricultural waste such as algae fiber, beet pulp, coffee grounds and / or mixtures thereof.

[0037] Advantageously, the water-soluble polymer is natural and water-retaining. More specifically, it can be a natural water-retaining additive with lubricating properties. It can be derived from natural and renewable resources, or even from waste.

[0038] More specifically, the preferred natural water-soluble polymer or water-retaining additive may be selected from: - Cellulose ethers (HPMC, HEC, HPC, CMC). - Synthetic polymers (e.g., polyethylene glycol, polyvinyl alcohol). - Guar gum, carob gum, or xanthan gum, - Alginate, agar, carrageenan, - Pectin or hemicellulose, - Functionalized or unfunctionalized cellulose nanocrystals or nanofibers - Mineral fillers, such as water-retaining fillers, - Hydrophobic additives, such as waxes, drying oils, or polymer emulsions, etc. - Cellulose fiber functionalizing additives, such as AKD (alkyl ketene dimer), rosin resin, or ASA (alkenyl succinic anhydride), and - A mixture of them.

[0039] When performing heat compression drying, it may be necessary to use specific molds and / or use these molds in a specific manner.

[0040] For example, the hot compression drying step 16 can be performed using a hot press by opening the hot press at least once and then closing it again, so that the moisture is discharged in the form of water vapor.

[0041] As an alternative or supplement, the hot compression drying step 16 can be carried out using a hot press with at least one perforated element, so that water is discharged in the form of steam through the perforation of the at least one element.

[0042] Fine-tuning of the hot compression parameters may also be required. More specifically, the hot compression drying step 16 is carried out at a temperature substantially between 100 and 200°C, preferably substantially between 120 and 180°C, and / or at a pressure substantially between 1 and 40 MPa.

[0043] As can be clearly seen from the above, the manufactured article 1 can advantageously be entirely biological, biodegradable, recyclable, and reusable in the paper / paperboard sector.

[0044] The present invention is not limited to the embodiments previously described, but extends to all embodiments covered by the present invention.

Claims

1. A method (10) for manufacturing an article (1) based on cellulose fibers, comprising the following steps: • The dry matter is mixed with water (12), the dry matter comprising at least 80% to 99%, preferably 90% to 99%, of cellulose fibers, and 1% to 20%, preferably 1% to 10%, of a water-soluble polymer or water-retaining polymer, the water-soluble polymer preferably being natural and cold-soluble, more preferably having long molecular chains, to obtain a cellulose fiber-based slurry, the dry matter concentration of which is substantially between 10% and 70% by weight, preferably between 20% and 50%, more preferably between 20% and 30%. • Without drying, the slurry is molded into a 2D or 3D shape in a mold of the article to be manufactured (14). • The slurry formed in the mold is dried by thermal compression (16).

2. The manufacturing method (10) according to the preceding claim, wherein the mixing (12) is carried out in a twin-screw extruder.

3. The manufacturing method (10) according to any of the preceding claims, wherein the slurry forming step (14) is carried out at room temperature.

4. The manufacturing method (10) according to any of the preceding claims, wherein the dry matter to be mixed (12) further comprises cellulose nanocrystals, nanofibrils or microfibrils at a concentration between 0.01% and 50% by weight of dry matter, preferably between 1% and 20%.

5. The manufacturing method (10) according to any of the preceding claims, wherein the dry matter to be mixed (12) further comprises at least one foaming agent of the surfactant type with a concentration between 0.01% and 10% by weight of the dry matter.

6. The manufacturing method (10) according to any of the preceding claims, wherein the molding step (14) of the slurry is performed by injection molding.

7. The manufacturing method (10) according to any one of claims 1 to 5, wherein the slurry forming step (14) is performed by transfer molding.

8. The manufacturing method (10) according to any of the preceding claims, wherein the cellulose fibers (12) to be mixed are derived from pulp.

9. The manufacturing method (10) according to any of the preceding claims, wherein the water-soluble polymer is natural and has water-retaining properties.

10. The manufacturing method (10) according to the preceding claim, wherein the preferably natural water-soluble polymer or water-retaining additive may be selected from: • Cellulose ethers (HPMC, HEC, HPC, CMC). • Synthetic polymers (e.g., polyethylene glycol, polyvinyl alcohol). • Guar gum, carob gum, or xanthan gum, • Alginate, agar, carrageenan, • Pectin or hemicellulose, • Functionalized or unfunctionalized cellulose nanocrystals or nanofibers, and • Its mixture.

11. The manufacturing method (10) according to any of the preceding claims, wherein the thermal compression drying step (16) is carried out at a temperature substantially between 100 and 200°C, preferably between 120 and 180°C, and / or at a pressure substantially between 1 and 40 MPa.

12. The manufacturing method (10) according to any of the preceding claims, wherein the hot compression drying step (16) is carried out using a hot press by opening and closing the hot press at least once to allow water to be discharged in the form of water vapor.

13. The manufacturing method (10) according to any of the preceding claims, wherein, The hot compression drying step (16) is carried out by using a hot press with at least one perforated element, so that water is discharged in the form of steam through the perforation of at least one of the elements.

14. An article based on cellulose fibers (1) that comprises or consists of the following components: • Cellulose fibers with a dry matter concentration of 80% to 99% by weight, preferably between 90% and 99%, and • A water-soluble polymer, or a water-retaining polymer and / or additive with a dry matter concentration of between 1% and 20% by weight, preferably between 1% and 10%, wherein the water-soluble polymer is preferably natural and cold-soluble.

15. The article (1) according to the preceding claim constitutes a three-dimensional package.

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