Moulded cellulose pulp product
A molded cellulose pulp product using eucalyptus Kraft chemical fiber with additives and a thermoplastic coating addresses the inadequacies of existing products, providing enhanced mechanical strength and barrier properties for food packaging.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-10-02
- Publication Date
- 2026-04-09
AI Technical Summary
Existing molded cellulose pulp products struggle to replace single-use plastics in food packaging due to inadequate mechanical properties and barrier capabilities against water, oils, and fats, while using eucalyptus Kraft chemical fiber as a dominant fiber has been challenging.
A molded cellulose pulp product comprising 70-100% eucalyptus Kraft chemical fiber with hydrophobic and oleophobic additives, and a thermoplastic polymer coating, produced through wet thermoforming and drying processes, achieving uniformity and mechanical strength.
The product exhibits superior mechanical properties and resistance to water, oils, and greases, making it suitable for rigid food packaging applications with reduced production cycles.
Smart Images
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Abstract
Description
[0001] DESCRIPTION TITLE OF THE INVENTION MOLDED CELLULOSE PULP PRODUCT TECHNICAL FIELD The present invention relates to molded cellulose pulp products. Additionally, the invention relates to a process for producing the molded cellulose pulp product. The invention has application in the paper and packaging industries. PRIOR ART Pollution from non-compostable fossil-based plastics is currently one of the most pressing environmental issues, with the mass production and use of petroleum-derived plastic packaging contributing significantly to this increase in the accumulation of plastics and microplastics in the environment. This pollution has harmed the human ecological environment, namely the oceans and freshwater resources of the planet. One type of plastic-based product is single-use packaging, which has been subject to increasingly restrictive measures regarding its application and use.Molded cellulose pulp packaging, also known as molded cellulose or molded pulp products, represents an alternative to products made from fossil-based plastics. In fact, these products have a long history of use in applications such as egg trays and fruit packaging, and are commonly produced using fibers obtained from recycled paper and cardboard, or fibers from sugarcane bagasse, bamboo, or straw. The production of these products essentially involves a simple process: a mixture of water and paper, usually from cardboard, newspaper, or a mixture of both, is subjected to disintegration, molding, pressing, and drying processes. Various efforts have been made to develop new production processes for this type of product with optimized resulting properties according to the intended application and in different sectors.Specifically in the food sector, the need to replace single-use packaging leads to the development of advanced alternatives based on molded cellulose products that can be applied not only to the transport and packaging of foods with low handling requirements, such as fruits and vegetables, but also to the packaging of ready-to-eat foods and meals. In this case, the developed products, in addition to exhibiting adequate mechanical resistance, must demonstrate barrier capacity against water, oils, and fats, maintaining food safety and preventing leaks or staining of surfaces or objects.Patent application EP3947191 A1 discloses a molded cellulose article that incorporates an alkyl ketene dimer (AKD), an aqueous emulsion based on fossil waxes, and a coating formulation consisting of a vinyl acetate and vinyl alcohol polymer, isothiazolinone, polyalkylene glycol, or a combination thereof, wherein the article exhibits grease and water resistance properties without the need for a fluorinated compound in its composition. Examples of fiber pulp types for use in the invention of patent application EP3947191 A1 include sugarcane fiber, bagasse, bamboo, wheat straw, and miscanthus. Patent JP7528636 B2 discloses a molded pulp article consisting of at least 50% by mass, or even entirely, of non-wood fibers. These fibers can be chosen from cotton, linen, hemp, straw, sisal hemp, jute, flax, bamboo, bagasse, among others.When not entirely composed of non-wood fibers, the article may also include wood pulp from softwoods and hardwoods, such as, for example, fir and pine; and acacia, eucalyptus, beech and poplar, respectively. The fiber composition described in the patent allows for the incorporation of oil and water resistance into the article even if the amount of additives commonly added for this purpose is reduced or even not added. Patent application JP2003147700 A discloses a molded cellulose product with water and moisture resistance properties that, by incorporating a water-repellent additive (an emulsion of a wax, or an emulsion of a resin, used alone or in combination) into the cellulose pulp, requires a smaller amount of a surface coating of an additive that promotes resistance to water absorption (also a composition based on waxes and resins) to obtain this resistance property.The fiber pulp is made from recycled paper. The urgent need to replace single-use plastics of fossil origin, and of these, in particular, non-compostable plastics that dominate the food packaging sector, leads to the constant search for and development of new molded cellulose product solutions that incorporate other and new types of fibers, thus leading to the development of new product ranges that help to urgently replace packaging based on fossil-based plastics. SUMMARY OF THE INVENTION The present invention relates to a molded cellulose pulp product characterized by comprising a fibrous composition and a non-fibrous composition, wherein said fibrous composition comprises 70% to 100% by weight of eucalyptus Kraft chemical fiber.In a preferred embodiment of the invention, the product comprises up to 30% by weight of fibers selected from the group consisting of softwood fibers, hardwood fibers, and non-wood fibers in its fibrous composition. In a preferred embodiment of the invention, the product comprises 100% by weight of eucalyptus Kraft chemical fiber in its fibrous composition. In a preferred embodiment of the invention, the eucalyptus Kraft chemical fiber is a bleached Kraft pulp, or a semi-bleached pulp, or an unbleached pulp, or a high-yield Kraft pulp. In a preferred embodiment of the invention, the product comprises in its non-fibrous composition at least one chemical additive consisting of hydrophobic additives, oleophobic additives, or mixtures thereof.In a preferred embodiment of the invention, the product comprises in its non-fibrous composition at least one chemical additive consisting of oxygen-resistant agents, wet and / or dry mechanical strength agents, retention agents, drainage aids, or mixtures thereof. In a preferred embodiment of the invention, the hydrophobic additives are at least one alkyl ketene dimer. In a preferred embodiment of the invention, the product further comprises a surface coating comprising additives selected from hydrophobic additives, oleophobic additives, oxygen-resistant agents, and mixtures thereof. In a preferred embodiment of the invention, the product further comprises a surface coating comprising at least one thermoplastic polymer. In a preferred embodiment of the invention, the product is a rigid food packaging. In a preferred embodiment of the invention, the product is a rigid food packaging such as trays, bowls, plates, and cups.The present invention also relates to a process for producing molded cellulose pulp product comprising the following steps: a) preparation of a pulp suspension with a fibrous composition comprising 70% to 100% by weight of eucalyptus Kraft chemical fiber to a consistency between 1.0% and 6.0%; b) formation of the molded cellulose pulp product by wet thermoforming of the suspension resulting from step a); c) drying of the product resulting from step b) to a dryness content of 1% to 5%. In a preferred embodiment of the invention, the process further comprises the following steps after step a) and before step b): i. refining to a ºSR of 20% to 40% of the suspension resulting from step a); ii. dilution of the suspension resulting from step i) to a consistency between 0.1% and 0.8%. In a preferred embodiment of the invention, the pulp suspension is prepared in step a) to a consistency between 3.0% and 4.0%.In a preferred embodiment of the invention, the dilution of the suspension in step ii) is to a consistency between 0.3 and 0.6%. In a preferred embodiment of the invention, the dilution of the suspension in step ii) is to a consistency between 0.3 and 0.4%. In a preferred embodiment of the invention, the fibrous composition of the suspension in step a) is 100% by weight of eucalyptus Kraft chemical fiber. In a preferred embodiment of the invention, the process further comprises an additional step of adding to the suspension, at any stage of the production process, chemical additives selected from hydrophobic additives, oleophobic additives and mixtures thereof. In a preferred embodiment of the invention, the hydrophobic additives are at least one alkyl ketene dimer.In a preferred embodiment of the invention, the process further comprises an additional step of adding to the suspension, at any stage of the production process, chemical additives selected from oxygen-resistant agents, wet and / or dry mechanical strength agents, retention agents, drainage aids and mixtures thereof. In a preferred embodiment of the invention, the process further comprises, after step c), a step of applying a coating to its surface comprising chemical additives selected from hydrophobic additives, oleophobic additives, oxygen-resistant agents, and mixtures thereof. In a preferred embodiment of the invention, the process further comprises, after step c), a step of applying a coating to its surface of at least one thermoplastic polymer.BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows the bursting index values for boards made up of: A - 100% by weight of bleached sugarcane bagasse fibers; B - 100% by weight of bleached eucalyptus Kraft chemical fibers; C - 80% by weight of bleached eucalyptus Kraft chemical fibers + 20% by weight of a mixture of bleached pine and fir Kraft chemical fibers; D - 100% mixture of pine and fir fibers. Figure 2 shows the tensile index values for boards made up of: A - 100% by weight of bleached sugarcane bagasse fibers; B - 100% by weight of bleached eucalyptus Kraft chemical fibers; C - 80% by weight of bleached eucalyptus Kraft chemical fibers + 20% by weight of a mixture of bleached pine and fir Kraft chemical fibers; D - 100% mixture of pine and fir fibers.Figure 3 shows the tear index values for boards made up of: A - 100% by weight of bleached sugarcane bagasse fibers; B - 100% by weight of bleached eucalyptus Kraft chemical fibers; C - 80% by weight of bleached eucalyptus Kraft chemical fibers + 20% by weight of a mixture of bleached pine and fir Kraft chemical fibers; D - 100% mixture of pine and fir fibers. Figure 4 shows the tensile stiffness values for boards made up of: A - 100% by weight of bleached sugarcane bagasse fibers; B - 100% by weight of bleached eucalyptus Kraft chemical fibers; C - 80% by weight of bleached eucalyptus Kraft chemical fibers + 20% by weight of a mixture of bleached pine and fir Kraft chemical fibers; D - 100% mixture of pine and fir fibers.Figure 5 shows the bending stiffness values for boards made up of: A - 100% by weight bleached sugarcane bagasse fibers; B - 100% by weight bleached eucalyptus Kraft chemical fibers; C - 80% by weight bleached eucalyptus Kraft chemical fibers + 20% by weight of a mixture of bleached pine and fir Kraft chemical fibers; D - 100% mixture of pine and fir fibers. Figure 6 shows the tear index values for boards made up of: A - 100% by weight unbleached eucalyptus Kraft chemical fibers; B - 100% by weight high-yield eucalyptus Kraft chemical fibers. Figure 7 represents the tensile index values for boards made of A - 100% by weight of unbleached eucalyptus Kraft chemical fibers; B - 100% by weight of high-yield eucalyptus Kraft chemical fibers.Figure 8 represents the tear index values for boards made up of A - 100% by weight of unbleached eucalyptus Kraft chemical fibers; B - 100% by weight of high-yield eucalyptus Kraft chemical fibers. DETAILED DESCRIPTION OF THE INVENTION A molded cellulose pulp product comprising mainly eucalyptus Kraft chemical fiber is described herein. It is common in the art to also refer to these products as molded cellulose products or molded pulp products, as mentioned, for example, by the International Molded Fiber Association (IMFA, https: / / www.imfa.org / ). In fact, this type of designation is consensual in the art and among the various stakeholders globally.A molded cellulose pulp product, within the scope of the present invention, relates to a product consisting of cellulose fibers, produced from a suspension of cellulose fiber pulp that is subjected to different molding, pressing, and drying processes in order to form any three-dimensional shape for packaging solid and / or liquid foods. These products need to exhibit specific weights, thicknesses, densities, and mechanical strength properties, such as bursting, tensile, tear, and bending resistance, to remain intact during food packaging, both during storage until consumption and during consumption in the case of fast food.Therefore, they should not be confused with other cellulose fiber-based products such as, for example, papers used for hygienic and sanitary purposes, whether in domestic or public environments (tissue papers), printing papers, and packaging papers and cardboards. In the case of packaging papers and cardboards, these have a completely different structure from that of the three-dimensional cellulose products of the present invention. Examples of these packaging papers include papers used as liners (board), which correspond to the paper commonly used to make boxes, constituting the outer layer(s) of a corrugated cardboard sheet. These are usually two-layer products, a top layer and a bottom layer. There is also the fluting between two or more liners, which is called fluting paper (or corrugated medium).Examples of molded pulp products, or molded cellulose products, or molded paste products, within the scope of the present invention include, but are not limited to, trays, cups, plates, and bowls. Eucalyptus Kraft chemical fiber is commonly used for the specific purpose of producing printing and writing papers, due to its biometric properties that confer homogeneity and smoothness to the paper produced. It has not, until now, been used as the dominant fiber in the fibrous composition in the production of molded cellulose products for food applications.In fact, prior benchmarking, based on technical, scientific, and market information, established the general idea that experts in the field would find it difficult to produce molded cellulose materials from eucalyptus Kraft fiber with good performance that could compete with existing products on the market, commonly produced using recycled paper or cardboard fibers, or fibers from bagasse, sugarcane, bamboo, or straw. Thus, surprisingly, it was found that the molded cellulose pulp product according to the present invention, consisting mainly of eucalyptus Kraft chemical fiber, constitutes an alternative for the production of molded cellulose packaging to replace single-use packaging for food applications, with performance suitable for that application in terms of its mechanical properties.In fact, it was surprisingly observed that a "short" cellulose fiber, such as eucalyptus fibers are considered in the art field (smaller fiber dimensions compared to softwood cellulose fibers), allowed molded pulp products with the ability to form the molded pulp product, stable maintenance of the required three-dimensionality, product homogeneity, and mechanical properties necessary for such products, which, until now, would only be expected for molded pulp products made of "long" cellulose fibers, such as pine and fir wood fibers, or fibers from non-woody materials, such as bagasse, sugarcane, bamboo, or straw fibers.Contrary to expectations, molded pulp products made primarily from eucalyptus Kraft chemical fiber exhibit highly uniform formation and an absence of defects, in contrast to molded pulp products made from softwood Kraft chemical fibers which, under identical production conditions, showed non-uniform fiber density. Furthermore, shorter production cycles were observed with eucalyptus Kraft chemical fibers compared to softwood Kraft chemical fibers and sugarcane bagasse fibers. Thus, eucalyptus Kraft chemical fibers demonstrate remarkable suitability for the production of molded pulp products.Within the scope of the present invention, a molded cellulose pulp product, also referred to in the art as a molded cellulose product or a molded pulp product, refers to a cellulose fiber-based product of any three-dimensional shape, produced through any process in which a suspension of a cellulose fiber pulp is subjected to different molding, pressing, and drying processes until the molded cellulose product is formed with the desired three-dimensional shape. Within the scope of the present invention, the term "mostly eucalyptus Kraft chemical fiber" refers to 70% to 100% by weight of eucalyptus Kraft chemical fiber based on its fibrous composition, with respect to the fibrous composition of the molded cellulose product.In one embodiment, the remaining fibrous composition consists of softwood fibers, hardwood fibers, and non-wood fibers. Within the scope of the present invention, softwood fibers refer to cellulosic fibers from, but not limited to, pine, fir, and mixtures thereof. Within the scope of the present invention, hardwood fibers refer to cellulosic fibers from, but not limited to, eucalyptus, birch, and mixtures thereof. Within the scope of the present invention, non-wood fibers refer to fibers from materials such as, for example, but not limited to, bamboo, wheat straw, sugarcane bagasse, and mixtures thereof.In one embodiment, the wood fibers from softwoods, hardwoods, and non-wood materials are derived from Kraft chemical pulps, high-yield Kraft chemical pulps, sulfite chemical pulps, mechanical pulps, thermomechanical pulps, chemical-mechanical pulps, and chemical-thermomechanical pulps. In one embodiment, these pulps are further bleached, semi-bleached, and unbleached pulps. Within the scope of the present invention, the non-fibrous composition refers to the constitution of the molded cellulose pulp product with additives such as, but not limited to, hydrophobic additives, oleophobic additives, oxygen resistance agents, wet and / or dry mechanical resistance agents, retention agents, and drainage aids. Within the scope of the present invention, hydrophobic additives are additives that incorporate hydrophobic properties into the product for resistance to water and moisture.Within the scope of the present invention, oleophobic additives are additives that incorporate oil and grease resistance properties into the product. In one embodiment, hydrophobic additives are used, i.e., used to incorporate water and moisture resistance properties into the product of the present invention, such as, but not limited to, alkyl ketene dimers (AKD), alkenyl succinic anhydrides (ASA), or rosin derivatives. In another embodiment, oleophobic additives are used, i.e., used to incorporate oil and grease resistance properties into the product of the present invention, such as, but not limited to, waxes, polyvinyl alcohol derivatives, and polyfluoroalkyl substances. In one embodiment, the additives and their mixtures are added to the fiber suspension during the product production process or to the surface of the molded cellulose pulp product, in this case as a coating.In one embodiment, the method of applying the product to the surface consists of applying it in an aqueous solution by spraying. Additionally, the person skilled in the art has at their disposal various other techniques and means to promote the application of the aforementioned additives to the surface. In one embodiment, the additives described above and their mixtures can be added to the fiber suspension at any time during the production of the molded cellulose product of the present invention. In one embodiment, at least one alkyl ketene dimer (AKD) is added. In another embodiment, the non-fibrous composition further comprises additives that are applied as coatings to the surface of the molded cellulose pulp product, such as, but not limited to, at least one thermoplastic polymer of fossil origin, of bio-based origin, or mixtures thereof.In one embodiment, additives are used, such as, but not limited to, oxygen-resistant agents, wet and / or dry mechanical strength agents, and retention and drainage aids. Within the scope of the present invention, a thermoplastic polymer refers to polymeric compounds that, upon heating, soften and melt, flowing as a viscous liquid, and solidify again after cooling. This is a reversible physical transformation. These additives can be applied by lamination or extrusion. Additionally, the skilled craftsman has at his disposal various other techniques and means to promote the surface application of the aforementioned additives. In one embodiment, all these additives are applied in whatever quantities are necessary to promote in the molded cellulose pulp product of the present invention water and moisture resistance properties and oil and grease resistance properties.Within the scope of the present invention, wet thermoforming refers to a process for producing molded cellulose products in which a suction tool dips into the fiber pulp suspension and aspirates it, leaving the fibers in the form of a filter cake in the tool. The suction tool is mounted on a device that transfers the component from station to station. It then moves to a flexible mold in the pre-pressing station before transferring the component to a hot press. Product formation occurs by molding due to the effect of pressure, temperature, and vacuum. Within the scope of the present invention, the suction time refers to the time the suction tool is in the headbox aspirating fibers.Within the scope of the present invention, pre-pressing refers to a step in the wet thermoforming process in which a product pre-formed in the suction tool is pre-pressed and dehydrated by a silicone (actuated by compressed air) and by pressing with an electric cylinder. Within the scope of the present invention, hot pressing refers to a step in the wet thermoforming process in which a pre-pressed product is subjected to pressure, exerted by an electric cylinder, and heated by tools for this purpose. The times of the pre-pressing and hot pressing steps are crucial for the production cycles of a molded pulp product, and the shortest possible times are desirable for the most efficient production of the products discussed in the present invention.Within the scope of the present invention, chemical cellulose fiber pulp corresponds to cellulose pulp produced exclusively through any chemical process that causes the dissolution of lignin in the wood in order to release the fibers from the matrix. Within the scope of the present invention, hot press (section 4, Figure 34): the pre-pressed article is released in the lower tool, and then subjected to pressure, exerted by an electric cylinder, and heated by the upper and lower tools (Figure 38). The applied temperature varies between 200 and 240 ºC and the highest achievable pressure is about 20 kN. The time of the hot pressing phase can also be controlled. The adjustment of all these settings depends on the furnace. Within the scope of the present invention, Kraft refers to Kraft cooking, or sulfate cooking.This chemical process consists of cooking the wood in a cooking liquor usually composed of sodium hydroxide and sodium sulfide, at temperatures of approximately 140 to 180 °C. Within the scope of the present invention, Kraft pulp refers to pulp obtained by Kraft cooking. Within the scope of the present invention, eucalyptus Kraft chemical fiber refers to a fiber obtained within the scope of a Kraft cooking chemical process of eucalyptus wood. Within the scope of the present invention, high yield corresponds to yields ≥ 60% within the scope of a Kraft cooking chemical process. Within the scope of the present invention, high-yield Kraft pulp refers to a Kraft pulp produced through a Kraft cooking chemical process with a yield greater than 60%.Within the scope of the present invention, the cooking yield is calculated using the following formula: pulp mass / wood mass ^ 100 (weights on an absolutely dry basis). Within the scope of the present invention, and according to the definition of the Confederation of European Paper Industries (CEPI) (Pulp and Paper Industry - Definitions and Concepts, CEPI – January 2021), a mechanical pulp corresponds to a pulp of cellulosic fibers produced through mechanical processes that separate and defibrate the wood until the pulp is formed. Chemical pretreatments may also be included in the production of mechanical pulps. Mechanical pulps are thus designated according to their production method and inclusion, or not, of pretreatments, as mechanical pulp, thermomechanical pulp (TMP), chemical-mechanical pulp (CMP) and chemical-thermomechanical pulp (CTMP).Mechanical pulp corresponds to pulp obtained by mechanical means of wood processing; thermomechanical pulp corresponds to pulp obtained by mechanical means with a pre-treatment at high temperatures and pressures; and chemical-mechanical and chemical-thermomechanical pulps correspond to pulps obtained by mechanical means preceded by chemical pre-treatments. Within the scope of the present invention, unbleached pulp corresponds to pulp of cellulosic fibers that is not subjected to any bleaching process, that is, any process of removing residual lignin and contaminants from the cellulosic pulp after cooking. Within the scope of the present invention, bleached pulp corresponds to pulp of cellulosic fibers that is subjected to at least one bleaching process until it reaches an ISO (ISO 2470) whiteness of ≥ 90%.Within the scope of the present invention, a semi-bleached pulp corresponds to a cellulose pulp that is subjected to at least one bleaching process until it reaches an ISO whiteness (ISO 2470) between that of unbleached pulp and that of bleached pulp. Within the scope of the present invention, basis weight means the quotient between the mass and the area of a sample. It is defined as the mass per unit area of paper. Measured according to ISO 536. Within the scope of the present invention, the Shopper-Riegler degree measurement corresponds to an empirical measure of pulp refining, in which a quantity of 1000 mL corresponds to 0°SR, while a zero quantity of drained liquid corresponds to 100°SR. Within the scope of the present invention, thickness corresponds to the perpendicular distance between the two faces of a sheet of paper determined under the conditions of the standard test method (100 kPa pressure and 200 mm). 2(area). Measured according to ISO 534. In the context of the present invention, density consists of the ratio between basis weight (quotient between the mass and the area of a sample, defined as the mass per unit area of paper) and thickness (perpendicular distance between the two faces of a sheet of paper). Measured according to ISO 534. In the context of the present invention, thickness corresponds to the perpendicular distance between the two faces of a sheet of paper determined under the conditions of the standardized test method (100 kPa pressure and 200 mm). 2(of area). Measured according to ISO 534. Within the scope of the present invention, bursting index means the ratio between the bursting strength (maximum uniform pressure supported by a paper test specimen in an area of 30.5 mm in diameter) and the basis weight. Measured according to ISO 2758. Within the scope of the present invention, tear index means the ratio between the tear strength (average force required to tear a sheet of paper in which an initial tear has been made) and the basis weight. Measured according to ISO 1974. Within the scope of the present invention, tensile strength refers to the force required to break a sheet of paper 15 mm wide when subjected to tension exerted at its ends under the conditions indicated in the test. Measured according to ISO 1924-2. Within the scope of the present invention, bending strength is the measure of resistance when the product is subjected to bending. Measured according to ISO 5270:2022 standard.Within the scope of the present invention, the tensile index corresponds to the ratio between tensile strength and basis weight. Measured according to ISO 1924-2. Within the scope of the present invention, pulp consistency refers to the ratio between the dry mass of the filterable material from a sample of the aqueous pulp suspension and the mass of the unfiltered sample. Consistency is expressed as a mass percentage (% m / m). Measured according to ISO 4119. Within the scope of the present invention, the dryness of the molded cellulose products is measured on a moisture analyzer balance immediately after the products are removed from the thermoforming equipment. The product described in the present invention thus consists of a molded cellulose product "mostly of eucalyptus Kraft fiber", that is, including from 70% to 100% by weight of eucalyptus Kraft chemical fiber based on the fibrous composition of the molded cellulose product.Another aspect of the present invention relates to the production process of the molded cellulose pulp product of the present invention, which comprises the following steps: a) preparation of a pulp suspension with a fibrous composition comprising 70% to 100% by weight of eucalyptus Kraft chemical fiber at a consistency between 1.0 and 6.0%; b) formation of the molded cellulose pulp product by wet thermoforming of the suspension resulting from step a); c) drying of the product resulting from step b). Dryness content of 1 to 5%. In a preferred embodiment, the process further comprises the following steps after step a) and before step b): i. refining the suspension resulting from step a) to a ºSR of 20 to 40; ii. diluting the suspension resulting from step i) to a consistency between 0.1-0.8%. In one embodiment, the paste suspension is prepared in step a) to a consistency between 3.0 and 4.0%. In one embodiment, the paste suspension is prepared in step a) to a consistency between 1.0 and 1.7%. In one embodiment, the paste suspension is prepared in step a) to a consistency between 4.5 and 6.0%. In one embodiment, the suspension in step ii) is diluted to a consistency between 0.3 and 0.6%. In one embodiment, the suspension in step ii) is diluted to a consistency between 0.3 and 0.4%.
[0002] Examples Example 1 A pulp suspension was made with 100% by weight of bleached eucalyptus Kraft chemical fibers, with respect to fibrous composition and a consistency of 1.5%. The resulting suspension was treated in a mechanical refining process at a °SR of 25. The resulting pulp was diluted to a consistency of 0.6%. The molded cellulose product, a tray, was formed by wet thermoforming. Finally, the final product was formed by pressure drying between two "male-female" molds to a dryness content of 1%. Example 2 Similarly to example 1, a pulp suspension was made with 80% by weight of bleached eucalyptus Kraft chemical fibers and 20% by weight of a mixture of bleached pine and fir Kraft chemical fibers, with respect to fibrous composition and a consistency of 1.5%. The resulting suspension was treated in a mechanical refining process to an ºSR of 35.The resulting pulp was diluted to a consistency of 0.6%. The molded cellulose product, a tray, was formed by wet thermoforming. Finally, the final product was formed by pressure drying between two male-female molds to a dryness of 1%. Example 3 Similarly to the previous examples, a pulp suspension was made with 70% by weight of bleached eucalyptus Kraft chemical fibers and 30% by weight of a mixture of bleached pine and fir Kraft chemical fibers, with respect to fiber composition and a consistency of 1.5%. The resulting suspension was treated in a mechanical refining process at an SR of 20. The resulting pulp was diluted to a consistency of 0.6%. The molded cellulose product, a tray, was formed by wet thermoforming. Finally, the final product was formed by pressure drying between two male-female molds until a dryness of 1% was achieved.Example 4: Similar to the previous examples, a pulp suspension was created with 100% by weight of bleached eucalyptus Kraft chemical fibers, with respect to fibrous composition and a consistency of 3%. The resulting suspension was treated in a mechanical refining process at a °SR of 20. The resulting pulp was diluted to a consistency of 0.3%. The molded cellulose product, a tray, was formed by wet thermoforming. Finally, the final product was formed by pressure drying between two "male-female" molds to a dryness of 3%. Example 5: Similar to the previous examples, a pulp suspension was created with 100% by weight of bleached eucalyptus Kraft chemical fibers, with respect to fibrous composition and a consistency of 5%. The resulting suspension was treated in a mechanical refining process at a ºSR of 40. The resulting pulp was diluted to a consistency of 0.45%.The molded cellulose product, a tray, was formed by wet thermoforming. Finally, the final product was formed by pressure drying between two "male-female" molds to a dryness content of 5%. Example 6 Similarly to the previous examples, a pulp suspension was made with 100% by weight of unbleached eucalyptus Kraft chemical fibers, with respect to fibrous composition and a consistency of 5%. The resulting suspension was treated in a mechanical refining process at an SR of 40. The resulting pulp was diluted to a consistency of 0.45%. The molded cellulose product, a tray, was formed by wet thermoforming. Finally, the final product was formed by pressure drying between two "male-female" molds to a dryness content of 5%.Example 7: Similar to the previous examples, a pulp suspension was made with 100% high-yield eucalyptus Kraft chemical fibers, with respect to fibrous composition and a consistency of 1.5%. The resulting suspension was treated in a mechanical refining process at a 25°SR and a 35°SR. The resulting pulp was diluted to a consistency of 0.6%. The molded cellulose product, a tray, was formed by wet thermoforming. Finally, the final product was formed by pressure drying between two "male-female" molds to a dryness content of 1%. Example 8: Similar to the previous examples, a pulp suspension was made with 100% by weight of bleached sugarcane bagasse fibers, with respect to fibrous composition and a consistency of 1.5%. The resulting suspension was treated in a mechanical refining process to an ºSR of 35. The resulting pulp was diluted to a consistency of 0.6%.The molded cellulose product, a tray, was formed by wet thermoforming. Finally, the final product was formed by pressure drying between two "male-female" molds to a dryness content of 1%. Example 9 Similarly to the previous examples, a pulp suspension was made with 100% by weight of softwood fibers, a mixture of bleached Kraft chemical fibers of pine and fir, with respect to fibrous composition and a consistency of 1.5%. The resulting suspension was treated in a mechanical refining process at an SR of 35. The resulting pulp was diluted to a consistency of 0.6%. The molded cellulose product, a tray, was formed by wet thermoforming. Finally, the final product was formed by pressure drying between two "male-female" molds to a dryness content of 1%.Results: Product Formation Times Table 1 – Values for suction times, pre-pressing times, and hot pressing times for the different fibers considered. Considering that increasing the time in each section negatively impacts the formation cycles, i.e., the time it takes to produce a molded cellulose pulp product and start a new production cycle, bleached Kraft chemical fiber pulp from pine and fir showed the worst performance compared to the other fibers. Bleached sugarcane bagasse fiber pulp showed intermediate behavior, with suction times similar to those of bleached Kraft chemical fiber pulp from eucalyptus (which had short times), but pre-pressing and hot pressing times in line with those observed for bleached Kraft chemical fiber pulp from pine and fir (which had long times).Conversely, among all the pulps analyzed, the bleached eucalyptus Kraft chemical fiber pulp presents the best balance in terms of time required in all sections, which has a positive impact on productivity (Table 1). Homogeneity All boards, produced with the different pulps, were carefully evaluated for visual inspection. The corresponding backlit images are shown in Table 2. By analyzing the images, it was possible to detect the formation of critical irregularities when using bleached pine and fir Kraft chemical fiber pulp, but not visible when bleached pine and fir Kraft chemical fiber pulp was mixed with bleached eucalyptus Kraft chemical fiber pulp. In the case of bleached sugarcane bagasse fiber pulp, some areas with lower fiber density were observed.However, the fiber distribution was more homogeneous than for bleached Kraft chemical fiber pulp from pine and fir. Trays produced with 100% bleached Kraft chemical fiber pulp from eucalyptus stand out for their very homogeneous formation and absence of defects. Table 2 – Images of trays produced with different pulps, observed against the light. Mechanical Properties: Mechanical properties were measured for the products produced as described in Examples 1 to 7, and also for products 5 consisting of 100% sugarcane fibers and 100% softwood fibers, a mixture of pine and fir fibers, produced as described in Examples 8 and 9. These three types of fibers represent the most commonly used fibers for the production of this type of product. Mechanical properties were also measured for a commercial product consisting of sugarcane fibers, which also serves as a reference. Grammage, Thickness and Density: Table 3 – Grammage, thickness and density values for the molded pulp products considered.Grammage Thickness Density Product (g / m²) (μm) (g / cm²) Commercial plate 326 495 0.66 100% fiber Without 372 597 0.623 bleached bagasse sugarcane refining 35 °SR 383 585 0.655 Without 100% chemical fiber 372 633 0.59 bleached Kraft refining 25 °SR 366 596 0.62 eucalyptus 35 °SR 370 552 0.67 80% chemical fiber Without 373 626 0.6 bleached Kraft refining eucalyptus + 20% 25 °SR 351 590 0.6 mixture of chemical fibers bleached Kraft pine and 35 °SR 378 595 0.638 of fir Without 100% chemical fiber 377 669 0.56 refining Bleached Kraft of 25 °SR 370 610 0.61 pine and fir 35 °SR 389 575 0.68 It was verified (Table 3) that the produced boards have the same basis weight on both the underside and the sides, allowing us to conclude the uniformity and suitability of the eucalyptus fiber pulps considered in this invention to a molded cellulose production process, similarly to other pulps commonly used in molded cellulose products.Values also in agreement with those verified for the commercial sample used here as a reference. Homogeneity of thickness and density values was also observed between the values obtained for formulations with eucalyptus fiber, only with sugarcane fiber, and only with resinous fibers. Values also in agreement with those verified for the commercial sample used here as a reference. Bursting Index Quite satisfactory values were observed (Figure 1) for the bursting index of products made with eucalyptus fiber, demonstrating their suitability for the production of molded cellulose products. A very similar behavior was observed for the bursting index of boards made with eucalyptus fiber compared to the values observed for products made only with sugarcane pulp.Higher values were even observed for a 35 ºSR refinement for products made from eucalyptus fiber compared to the values observed for products made only from sugarcane pulp. The values for products made from eucalyptus fiber are also comparable to those observed for the commercial product. Tensile Index Quite satisfactory values were observed (Figure 2) for the tensile index of products made from eucalyptus fiber, demonstrating their suitability for the production of molded cellulose products. A very similar behavior was observed for the tensile index of products made from eucalyptus fiber compared to the values observed for products made only from sugarcane fiber or only from softwood fibers.The values for products made from eucalyptus fiber are also in line with those observed for the commercial product. For example, products made with 100% BEKP and 80% BEKP + 20% BSKP, refined to 35°SR, show tensile indices very close to the commercial sample. Tear Index Quite satisfactory values were observed (Figure 3) for the burst index of products made from eucalyptus fiber, even exceeding the selected commercial reference, demonstrating their suitability for the production of molded cellulose products. A very similar behavior was observed for the tear index of products made from eucalyptus fiber compared to the values observed for products made only from sugarcane fiber or only from softwood fibers.Tensile stiffness: Quite satisfactory values were observed (Figure 4) for the tensile stiffness of products made from eucalyptus fiber, demonstrating their suitability for the production of molded cellulose products. A very similar behavior was observed for the tensile stiffness of products made from eucalyptus fiber compared to the values observed for products made only from sugarcane fiber or only from softwood fibers. For example, products made with 100% sugarcane, 100% BEKP, and 80% BEKP + 20% BSKP, refined to 35°SR, show values similar to the commercial reference. Bending stiffness: Quite satisfactory values were observed (Figure 5) for the bending stiffness of products made from eucalyptus fiber, demonstrating their suitability for the production of molded cellulose products.A very similar behavior was observed for the bending stiffness of products made from eucalyptus fiber compared to the values observed for products made only from sugarcane fiber or only from softwood fibers. In fact, all formulations tested showed values higher than the commercial reference. Results for these mechanical properties were obtained for the product made up of 70% by weight of bleached eucalyptus Kraft chemical fiber and 30% by weight of a mixture of bleached pine and fir Kraft chemical fiber, in line with those observed for the properties of products with 100% by weight of bleached eucalyptus Kraft chemical fiber and with 80% by weight of bleached eucalyptus Kraft chemical fiber and 20% by weight of a mixture of bleached pine and fir Kraft chemical fiber, with respect to the fibrous composition of the molded cellulose product.The same behavior was observed for the product with 100% by weight of unbleached Kraft eucalyptus chemical fiber. The products resulting from Examples 4 and 5 also demonstrated mechanical properties in line with those observed in the remaining examples; that is, the different mechanical properties showed very similar behavior to that observed for products consisting only of sugarcane bagasse fiber or only of resinous fibers, and for the commercial product considered. Regarding Example 7, Table 4 shows that there was also homogeneity in the values of basis weight, thickness, and density between the values obtained for the formulations with eucalyptus fiber, including the high-yield ones, compared to the formulations with only sugarcane fiber and the commercial sample used here as a reference. Table 4 - Basis weight, thickness, and density values for the molded pulp products considered.Grammage Thickness Density Product (g / m2) (μm) (g / cm3) Plate 326 495 0.66 commercial 100% fiber Without 372 597 0.62 bleached sugarcane bagasse refining 35 °SR 383 585 0.66 100% fiber Without 368 680 0.54 chemical refining Kraft non-bleached 25 °SR 379 611 0.62 35 °SR 369 553 0.67 eucalyptus 100% fiber Without 362 641 0.57 chemical refining eucalyptus 25 °SR 382 595 0.64 high yield 35 °SR 371 556 0.67 The Figures Examples 6, 7, and 8 demonstrated mechanical properties in line with those observed in the remaining examples; that is, the different mechanical properties showed a behavior very similar to that observed for the product with 100% high-yield eucalyptus Kraft chemical fiber, and for the products made up of 100% eucalyptus Kraft chemical fiber, and for the products made up only of sugarcane fiber, and for the commercial product considered.Oil and Grease Resistance: For products made with 100% bleached eucalyptus Kraft chemical fiber, their resistance to oils and greases was evaluated when: a) oleophobic additives were added to the fiber suspension during production, b) by spraying to create a coating with these additives, and c) by lamination also to create a coating with these additives. The Cobb-Unger method was applied for this evaluation. This method consists of measuring the oil absorption capacity of paper samples by weighing test specimens under controlled temperature and humidity conditions, before and after contact with a specific volume of castor oil for 30 seconds.The procedure described involves the use of a cylinder used in the classic Cobb test (conventionally used to determine water absorption in paper and cardboard samples) and has been adapted to comply with the relevant regulatory requirements for oil testing, as described by the SCAN-P 37:77 standard. The process begins with cutting the test specimens, which must have one circular end and one quadrangular end. Next, the apparatus is prepared by placing a lid on the cylinder to ensure the system is watertight. 62.5 mL of castor oil is poured into the central orifice of the cylinder, opening it using a metal clamp. It is important to clean any excess oil from the edges of the orifice. The test specimen is weighed and its initial mass recorded. The specimen is then placed in the cylinder, with the face to be tested facing the oil reservoir, aligning the circular part over the ends of the orifice and orienting the quadrangular part towards the user.A rubber shoe is placed on the test specimen to maintain its position. The stopwatch is started, and the cylinder is inverted to promote contact between the oil and the test specimen. At 25 seconds, the cylinder is returned to its initial position. At 28 seconds, the test specimen is removed from the cylinder and placed on a sheet of blotting paper, with the oil-exposed side facing upwards. At 30 seconds, excess oil is removed from the surface by pressing and wiping with absorbent paper. This action ends at 32 seconds, at which point the test specimen is weighed again, recording the final mass. Finally, the oil absorption is calculated by subtracting the initial mass of the test specimen from the final mass and dividing the result by the area of the cylinder orifice used. In case a) for a formulation consisting of 3% by weight of a commercial PFA and 1% by weight of a commercial AKD and 0.5% by weight, a Cobb-Unger value (g / m) was observed. 2) of 13.7. This value is lower than the corresponding value for the commercial sample plate considered, which is 18 g / m². 2 It was thus possible to verify the existence of oil and grease resistance properties in the product considered in option a). In case b), for the spray application of an aqueous solution of a commercial oleophobic additive, resulting in a coating of this solution of 7 g / m². 2, a Cobb-Unger value (g / m³) was observed 2 ) of 13. This value is lower than the corresponding value for the commercial sample plate considered, which is 18 g / m². 2 It was thus possible to verify the existence of oil and grease resistance properties in the product considered in option b). In case c), for the application by lamination of an aqueous solution of a commercial oleophobic additive, resulting in a coating of this solution of 7 g / m². 2, a Cobb-Unger value (g / m³) was observed 2) of 2.5. This value is lower than the corresponding value for the commercial sample plate considered, which is 18 g / m². 2 It was thus possible to verify the existence of oil and grease resistance properties in the product considered in option c).
Claims
CLAIMS 1. Molded cellulose pulp product characterized by comprising a fibrous composition and a non-fibrous composition, wherein said fibrous composition comprises 70% to 100% by weight of eucalyptus Kraft chemical fiber.
2. Molded cellulose pulp product according to claim 1 characterized by comprising up to 30% by weight of fibers selected from the group consisting of softwood fibers, hardwood fibers and non-wood fibers in its fibrous composition.
3. Molded cellulose pulp product according to claim 1 characterized by comprising 100% by weight of eucalyptus Kraft chemical fiber in its fibrous composition.
4. Molded cellulose pulp product according to any one of claims 1 to 3, characterized in that the eucalyptus Kraft chemical fiber is selected from the group consisting of bleached, semi-bleached, unbleached Kraft pulp and high-yield Kraft pulp. 5.A molded cellulose pulp product according to any one of claims 1 to 4, characterized in that the product comprises in its non-fibrous composition at least one chemical additive selected from the group consisting of hydrophobic additives, oleophobic additives and mixtures thereof.
6. Molded cellulose pulp product according to claim 5, characterized in that the hydrophobic additives are at least one alkyl ketene dimer.
7. Molded cellulose pulp product according to any one of claims 1 to 6, characterized in that the product comprises in its non-fibrous composition at least one chemical additive selected from the group consisting of oxygen-resistant agents, wet and / or dry mechanical strength agents, retention agents and drainage aids and mixtures thereof.
8. Molded cellulose pulp product according to any one of claims 1 to 7, characterized further by comprising a surface coating comprising additives selected from the group consisting of hydrophobic additives, oleophobic additives, oxygen-resistant agents and mixtures thereof. 9.Molded cellulose pulp product according to any one of claims 1 to 8, characterized by further comprising a surface coating comprising at least one thermoplastic polymer.
10. Molded cellulose pulp product according to any one of claims 1 to 9, characterized by being a rigid food packaging.
11. Molded cellulose pulp product according to claim 10, characterized by the packaging.
11. Rigid food waste to be selected from the group consisting of trays, bowls, plates and cups.
12. Process for producing the molded cellulose pulp product claimed in claims 1 to 11, characterized by comprising the following steps: d) preparation of a pulp suspension with a fibrous composition comprising 70% to 100% by weight of eucalyptus Kraft chemical fiber to a consistency between 1.0 and 6.0%; e) forming the molded cellulose pulp product by wet thermoforming of the suspension resulting from step a); f) drying the product resulting from step b) to a dryness content of 1 to 5%.
13. Process according to claim 12, characterized by further comprising the following steps after step a) and before step b): i. refining to a ºSR of 20 to 40 of the suspension resulting from step a); ii. dilution of the suspension resulting from step i) to a consistency between 0.1-0.8%. 14.Process according to any one of claims 12 to 13, characterized in that the paste suspension is prepared in step a) to a consistency between 3.0 and 4.0%.
15. Process according to any one of claims 12 to 14, characterized by the dilution.
15. Process according to any one of claims 12 to 15, characterized in that the dilution of the suspension from step ii) is to a consistency between 0.3 and 0.6%.
16. Process according to any one of claims 12 to 15, characterized in that the dilution of the suspension from step ii) is to a consistency between 0.3 and 0.4%.
17. Process according to any one of claims 12 to 16, characterized in that the fibrous composition of the suspension from step a) is 100% by weight of eucalyptus Kraft chemical fiber.
18. Process according to any one of the preceding claims 12 to 17, characterized in that it further comprises an additional step of adding to the suspension, at any time during the production process, chemical additives selected from the group consisting of hydrophobic additives, oleophobic additives and mixtures thereof.
19. Production process according to claim 18 characterized in that the hydrophobic additives are at least one alkyl ketene dimer. 20.A process according to any one of the preceding claims 12 to 19, characterized by further comprising an additional step of adding to the suspension, at any time during the production process, chemical additives selected from the group consisting of oxygen-resistant agents, wet mechanical strength agents and / or a.
20. Production process according to any one of claims 12 to 20 characterized by further comprising, after step c), a step of applying a coating to its surface comprising chemical additives selected from the group consisting of hydrophobic additives, oleophobic additives, oxygen resistance agents and mixtures thereof.
21. Production process according to any one of claims 12 to 20 characterized by further comprising, after step c), a step of applying a coating to its surface of at least one thermoplastic polymer.