SE545416C2

SE545416C2 - Composite products

Info

Publication number: SE545416C2
Application number: SE2151587A
Authority: SE
Inventors: Martin Malmqvist
Original assignee: Stora Enso Oyj
Priority date: 2021-12-22
Filing date: 2021-12-22
Publication date: 2023-09-05
Also published as: SE2151587A1; WO2023119003A1

Abstract

A composite product (10) comprises a cellulose and/or lignocellulose fiber matrix (20) and at least one polymerized fatty acid, or an oil or oil mixture comprising at least one polymerized fatty acid. The at least one polymerized fatty acid or the oil or oil mixture is distributed within at least a portion (22, 24) of the cellulose and/or lignocellulose fiber matrix (20). The composite product (10) is capable to be in contact with moisture and liquid and still significantly restricts absorption of such moisture or liquid into the cellulose and/or lignocellulose material of the composite product (20).

Description

COMPOSITE PRODUCTS TECHNICAL FIELD The present invention generally relates to composite products and substrates, and in particular to such composite products resistant against absorption of moisture, liquids and grease.

BACKGROUND With growing awareness for the environment and humanly induced climate change, the use of plastic items and products has come more and more into question. However, despite this concern the use of these items and products has grown vastly with new trends in lifestyles and consumer habits of the last decade. There is therefore a need to provide cost-effective composite materials that are derived from renewable feedstock. An example of such environmentally friendly composite material is cellulosic composites comprising cellulose and/or lignocellulose ﬁbers.

A common disadvantage of cellulosic composites is that they may be sensitive to exposure to moisture, liquids and/or grease. ln more detail, the cellulosic composite may absorb moisture, liquids and/or grease when in contact with moist or greasy goods or articles, or when exposed to, in particular, moisture or liquids from the surroundings. Such absorption may cause a deformation of the product made from the cellulosic composite and possible even a weakening of the structural integrity of the product.

There is therefore a need for composite substrates comprising cellulose and/or lignocellulose fibers and composite products and articles made therefrom that are resistant against absorption of moisture, liquids and grease.

SUMMARY lt is a general objective to provide composite substrates comprising cellulose and/or lignocellulose fibers and composite products made therefrom that are resistant against absorption of moisture, liquids and grease.

This and other objectives are met by embodiments of the present invention.

The present invention is deﬁned in the independent claims. Further embodiments of the invention are deﬁned in the dependent claims.

An aspect of the invention relates to a composite product comprising a cellulose and/or Iignocellulose fiber matrix oss: :m eﬁrê »a and at least one polymerized fatty acid or an oil or oil mixture comprising at least one polymerized fatty acid. The at least one polymerized fatty acid or the oil or oil mixture is distributed within at least a portion of the cellulose and/or Iignocellulose fiber matrix. The at least a portion of the cellulose and/or Iignocellulose ﬁber matrix extends from a first surface of the cellulose and/or Iignocellulose fiber matrix to a second, opposite surface of the cellulose and/or Iignocellulose ﬁber matrix.

Another aspect of the invention relates to a composite åjçﬁgsubstrate comprising a cellulose and/or Iignocellulose ﬁber matrix and at least one polymerizable fatty acid or an oil or oil mixture comprising at least one polymerizable fatty acid. The at least one polymerizable fatty acid or the oil or oil mixture is distributed within at least a portion of the cellulose and/or Iignocellulose fiber matrix. The at least a portion of the cellulose and/or Iignocellulose ﬁber matrix extends from a first surface of the cellulose and/or Iignocellulose fiber matrix to a second, opposite surface of the cellulose and/or Iignocellulose fiber matrix.

The composite products of the present invention are capable to be in contact with moisture and liquid and still signiﬁcantly restrict absorption of such moisture or liquid into the cellulose and/or Iignocellulose material of the composite products.

BRIEF DESCRIPTION OF THE DRAWINGS The embodiments, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which: Fig. 1 is a cross-sectional view of a composite product according to an embodiment; and Fig. 2 is a cross-sectional view of a composite product according to another embodiment. DETAILED DESCRIPTION The present invention generally relates to composite products and composite substrates comprising cellulose and/or Iignocellulose fibers, and in particular to such composite products resistant against absorption of moisture, liquids and grease.

Products comprising cellulose and/or lignocellulose fibers have become more and more popular as environmentally friendly replacements of plastic products, such as made of polystyrene or other plastic materials. Alternatives to plastics are needed, however, from environmental and sustainability point of view and due to possible health hazards associated with plastic materials with chemicals leakage from the plastic materials.

The present invention uses polymerized fatty acids and/or oils or oil mixtures comprising such polymerized fatty acids to form a composite product that is resistant against environmental conditions, such as moisture, liquid and grease. Hence, the polymerized fatty acids and/or oils or oil mixtures effectively prevent or at least restrict absorption of moisture, liquid and grease from the ambient environment or goods into the composite product. lt is known in the art to use an aqueous solution or emulsion of so-called hydrophobation and grease barrier agents, typically an aqueous solution or emulsion of starches. The prior art aqueous hydrophobation and grease barrier agents need to be applied to a cellulose and/or lignocellulose substrate prior to forming the cellulose and/or lignocellulose substrate into a final product since the cellulose material will absorb water from the aqueous hydrophobation and grease barrier agent causing undesired swelling and deformation of the cellulose material. This swelling and deformation can be compensated for during the forming process, for instance, by pressing, thermoforming or molding the swelled and deformed cellulose and/or lignocellulose substrate. However, such a swelling and deformation cannot be compensated for if it occurs in the formed ﬁnal product. Hence, the prior art aqueous hydrophobation and grease barrier agents need to be applied to the cellulose and/or lignocellulose substrate prior to forming.

The present invention applies at least one polymerizable fatty acid or an oil or oil mixture comprising at least one polymerizable fatty acid to a cellulose and/or lignocellulose fiber matrix and then polymerizes the at least one polymerizable fatty acid to obtain at least one polymerized fatty acid distributed within at least a portion of the cellulose and/or lignocellulose ﬁber matrix. The polymerizable fatty acids or the oils or oil mixtures of the invention do not cause the same degree of swelling and deformation of the cellulose and/or lignocellulose material as the aqueous solutions or emulsions. Hence, the need for compensating for any swelling and deformation is generally lower for the present invention as compared to using aqueous hydrophobation and grease barrier agents.---.

The present invention can achieve hydrophobation and grease prooﬁng effect also for cut edges in the composite product. The polymerized fatty acids or the oils or oil mixtures of the invention are distributed within the bulk of the cellulose and/or lignocellulose fiber matrix of the composite product to proof or impregnate the cellulose and/or lignocellulose ﬁber matrix or at least a thick portion thereof with the polymerized fatty acids or the oils or oil mixtures. Hence, also edges exposed when cutting the cellulose product will thereby present hydrophobation and grease prooﬁng effect and restrict absorption of moisture, liquids and grease.

An aspect of the invention therefore relates to a composite product comprising a cellulose and/or lignocellulose ﬁber matrix än and at least one polymerized fatty acid or an oil or oil mixture comprising at least one polymerized fatty acid. According to the invention, the at least one polymerized fatty acid or the oil or oil mixture is distributed within at least a portion of the cellulose and/or lignocellulose fiber matrix. The at least a portion of the cellulose and/or lignocellulose ﬁber matrix extends from a ﬁrst surface of the cellulose and/or lignocellulose fiber matrix to a second, opposite surface of the cellulose and/or lignocellulose ﬁber matrix.

The composite product of the invention, also referred to as composite article, could be regarded as a composite, and in particular a biocomposite, since it comprises a cellulose and/or lignocellulose ﬁber matrix and additionally comprises at least one polymerized fatty acid or an oil or oil mixture comprising at least one such polymerized fatty acid. The at least one polymerized fatty acid or the oil or oil mixture is then distributed within at least a portion of the cellulose and/or lignocellulose fiber matrix. This means that at least a portion of the composite product is thereby a composite betvveen a cellulose and/or lignocellulose material and at least one polymerized fatty acid or the oil or oil mixture. The at least one polymerized fatty acid or the oil or oil mixture is preferably in at least partly solid state within the at least a portion of the cellulose and/or lignocellulose ﬁber matrix. For instance, at least one polymerizable fatty acid or an oil or oil mixture comprising at least one polymerizable fatty acid could be distributed within the at least a portion of the cellulose and/or lignocellulose fiber matrix, which is further described herein. The at least one polymerizable fatty acid or the oil or oil mixture comprising the at least one polymerizable fatty acid is then in a liquid form. The at least one polymerizable fatty acid is then polymerized to form the at least one polymerized fatty acid or the oil or oil mixture comprising the at least one polymerized fatty acid distributed within the at least a portion of the cellulose and/or lignocellulose ﬁber matrix. The polymerization of the at least one polymerizable fatty acid causes the at least one polymerizable fatty acid to solidify forming a composite or biocomposite together with the cellulose and/or lignocellulose material of the cellulose and/or lignocellulose ﬁber matrix.

The at least one polymerized fatty acid or the oil or oil mixture distributed within at least a portion of the cellulose and/or Iignocellulose matrix protects the composite product or at least a portion thereof from ambient conditions, such as moisture, liquids or grease, which may come into contact with the composite product and its cellulose and/or Iignocellulose matrix. Thus, by distributing the at least one polymerized fatty acid or the oil or oil mixture within at least a portion of the cellulose and/or Iignocellulose matrix that at least a portion of the cellulose and/or Iignocellulose matrix is impregnated with the at least one polymerized fatty acid or the oil or oil mixture to obtain a hydrophobation and grease prooﬁng effect.

The at least one polymerized fatty acid or the oil or oil mixture is distributed within at least a portion 22, 24 of the cellulose and/or Iignocellulose ﬁber matrix 20, see Figs. 1 and 2. This at least a portion 22, 24 extends from a first surface 21 of the cellulose and/or Iignocellulose ﬁber matrix 20 to a second, opposite surface 23 of the cellulose and/or Iignocellulose ﬁber matrix Fig. 1 schematically illustrates a composite product 10 comprising a cellulose and/or Iignocellulose ﬁber matrix 20. ln the embodiment illustrated in Fig. 1, the at least one polymerized fatty acid or the oil or oil mixture is distributed within the cellulose and/or Iignocellulose fiber matrix 20 of the composite product 10. Hence, the at least one polymerized fatty acid or the oil or oil mixture is, in the embodiment shown in Fig. 1, distributed within and throughout the complete cellulose and/or Iignocellulose ﬁber matrix 20 and not merely within a portion thereof.

Fig. 2 illustrates another embodiment of a composite product 10 that has been processed in terms of compressed during manufacture. Hence, the composite product 10 shown in Fig. 2 comprises portions 22 that are hard pressed and portions 24 that are not pressed or only slightly pressed. ln an embodiment, the at least one polymerized fatty acid or the oil or oil mixture is distributed within the portions 22 of the cellulose and/or Iignocellulose ﬁber matrix 20 and thereby of the composite product 10 that have been hard pressed. ln another embodiment, the at least one polymerized fatty acid or the oil or oil mixture is distributed within the portions 24 of the cellulose and/or Iignocellulose fiber matrix 20 and thereby of the composite product 10 that have not been pressed or only pressed slightly. The portions 22, 24 of the cellulose and/or Iignocellulose ﬁber matrix 20 extends from a first surface 21 of the cellulose and/or Iignocellulose ﬁber matrix 20 to a second, opposite surface 23 of the cellulose and/or Iignocellulose fiber matrix 20 as shown in Fig. 2. This means that if merely one or multiple portions 22, 24 of the cellulose and/or Iignocellulose ﬁber matrix 20 comprises the at least one polymerized fatty acid or the oil or oil mixture that portion 22, 24 or those portions 22, 24 extends or extend through the whole cellulose and/or Iignocellulose ﬁber matrix 20, i.e., between opposite surfaces 21, 23 or sides of the cellulose and/or Iignocellulose ﬁber matrix The two opposite surfaces 21, 23 of the cellulose and/or Iignocellulose fiber matrix 20 could be substantially parallel to each other as shown in Fig. 2 but do not necessary have to be parallel to each other. The cellulose and/or Iignocellulose fiber matrix 20 could in turn extend through the complete thickness of the composite product 10. ln such a case, the tvvo opposite surfaces 21, 23 could also be regarded as ﬁrst and second, opposite surfaces of the composite product 10. However, in some applications, the composite product 10 could comprise additional material besides the cellulose and/or Iignocellulose fiber matrix 20, such as a surface layer of some other type of material. ln such a case, the at least a portion 22, 24 of the cellulose and/or lignocellulose ﬁber matrix 20 comprising the at least one polymerized fatty acid or the oil or oil mixture extends between opposite surfaces 21, 23 of the cellulose and/or Iignocellulose fiber matrix 20 but not between opposite surfaces of the cellulose product ln an embodiment, the at least one polymerized fatty acid or the oil or oil mixture is distributed within a complete thickness of the at least a portion 22, 24 of the cellulose and/or Iignocellulose fiber matrix 20. This means that the at least one polymerized fatty acid or the oil or oil mixture is distributed throughout the whole of the at least a portion 22, 24 of the cellulose and/or Iignocellulose ﬁber matrix 20 and not merely provided as a surface layer or coating. ln clear contrast, the at least one polymerized fatty acid or the oil or oil mixture is provided in and distributed throughout the complete thickness of the at least a portion of the cellulose and/or Iignocellulose fiber matrix With reference to Fig. 1, the at least one polymerized fatty acid or the oil or oil mixture is distributed within a complete thickness T of the cellulose and/or Iignocellulose fiber matrix 20, i.e., from a first or upper surface 21 of the cellulose and/or Iignocellulose ﬁber matrix 20 and of the composite product 10 to a second or lower surface 23 of the cellulose and/or Iignocellulose fiber matrix 20 and of the composite product ln Fig. 2, the hard pressed portions 22 of the cellulose and/or Iignocellulose ﬁber matrix 20 have a thickness T1. Hence, in a preferred embodiment, the at least one polymerized fatty acid or the oil or oil mixture is distributed within a complete thickness T1 of the hard pressed portions 22 of the cellulose and/or Iignocellulose fiber matrix 20. Correspondingly, the non-pressed or slightly pressed portionsof the cellulose and/or Iignocellulose fiber matrix 20 have a thickness T2 as shown in Fig. 2. Hence, in a preferred embodiment, the at least one polymerized fatty acid or the oil or oil mixture is distributed within a complete thickness T2 of the non-pressed or slightly pressed portions 24 of the cellulose and/or Iignocellulose ﬁber matrix ln an embodiment, the at least one polymerized fatty acid or the oil or oil mixture is homogenously distributed within the at least a portion of the cellulose and/or Iignocellulose fiber matrix. Thus, it is generally preferred if the at least one polymerized fatty acid or the oil or oil mixture is at least fairly homogenously distributed throughout the at least a portion of the cellulose and/or Iignocellulose fiber matrix so that the concentration of the at least one polymerized fatty acid or the oil or oil mixture is substantially the same throughout the at least a portion of the cellulose and/or Iignocellulose ﬁber matrix. ln an embodiment, the at least a portion of the cellulose and/or Iignocellulose fiber matrix is gsæsfëšysaturated with the at least one polymerized fatty acid or the oil or oil mixture. Thus, the at least a portion of the cellulose and/or Iignocellulose ﬁber matrix preferably comprises a sufficient amount of polymerized fatty acid(s) or oil or oil mixture to be f* š:::t::* ;;tf::r*ï?'.:' ;:*:*':.::f~::*:tff. saturatedf; with the at least one polymerized fatty acid or the oil or oil mixture. The at least one polymerized fatty acid or the oil or oil mixture will then provide an efficient hydrophobation or grease proofing effect to the at least a portion of the cellulose and/or Iignocellulose ﬁber matrix.

As mentioned in the foregoing and illustrated in Fig. 1, in an embodiment, the at least one polymerized fatty acid or the oil or oil mixture is distributed within the .g-gﬂcellulose and/or Iignocellulose ﬁber matrix 20. Hence, in this embodiment, not only a single portion or multiple, i.e., at least tvvo, separate portions of the cellulose and/or Iignocellulose ﬁber matrix 20 is or are treated with the at least one polymerized fatty acid or the oil or oil mixture. ln clear contrast, the at least one polymerized fatty acid or the oil or oil mixture is preferably distributed within the complete cellulose and/or Iignocellulose fiber matrix 20 and thereby preferably throughout the complete composite product 10 or the portion(s) thereof made of or comprising the cellulose and/or Iignocellulose fiber matrix ln an embodiment, the composite product comprises cellulose and/or Iignocellulose fibers forming the cellulose and/or Iignocellulose fiber matrix. Hence, in an embodiment, the composite product comprises cellulose, such as in the form of cellulose and/or Iignocellulose, i.e., a mixture of cellulose and lignin.

The fibers may contain lignin, such as in the form of Iignocellulose. The ﬁbers may additionally contain hemicellulose. ln a particular embodiment, the cellulose and/or Iignocellulose ﬁber matrix comprises cellulose and/or Iignocellulose pulp ﬁbers produced by chemical, mechanical and/or chemi-mechanical pulping of softvvood and/or hardwood. For instance, the cellulose and/or Iignocellulose pulp ﬁbers are in a form selected from the group consisting of sulfate pulp, sulfite pulp, dissolving pulp, thermomechanical pulp (TMP), high temperature thermomechanical pulp (HTMP), mechanical fiber intended for medium density ﬁberboard (MDF-ﬁber), chemi-thermomechanical pulp (CTMP), high temperature chemi- thermomechanical pulp (HTCTMP), and a combination thereof.

The cellulose and/or Iignocellulose ﬁbers can also be produced by other pulping methods and/or from other cellulosic or lignocellulosic raw materials, such as ﬂax, jute, hemp, kenaf, bagasse, cotton, bamboo, straw or rice husk. lt is also possible to use cellulose and/or Iignocellulose ﬁbers that are a mixture of fibers from different raw materials, such as a mixture of wood and any of the materials mentioned above. ln an embodiment, a single polymerized fatty acid is distributed within the at least a portion of the cellulose and/or Iignocellulose ﬁber matrix. ln another embodiment, a mixture of multiple different polymerized fatty acids is distributed within the at least a portion of the cellulose and/or Iignocellulose fiber matrix. lllustrative, but non-limiting, examples of such polymerized fatty acids that can be used include unsaturated fatty acids including monounsaturated fatty acids, such as oleic acid, elaidic acid and palmitoleic acid, and/or polyunsaturated fatty acids, such as linoleic acid and linolenic acid, including mixtures thereof, which have been polymerized. ln a preferred embodiment, the polymerized fatty acids are polyunsaturated fatty acids, a mixture of different polyunsaturated fatty acids or a mixture of at least one polyunsaturated fatty acid and at least one monounsaturated fatty acid, which have been polymerized. ln another embodiment, an oil comprising at least one polymerized fatty acid, including a mixture of different polymerized fatty acids, is distributed within the at least a portion of the cellulose and/or Iignocellulose ﬁber matrix. ln an embodiment, the oil is a vegetable oil or the oil mixture is a mixture of vegetable oils. ln a particular embodiment, the vegetable oil is selected from the group consisting of ﬂaxseed oil, avocado oil, sesame oil, safflower oil, sunflower oil, grapeseed oil, rapeseed oil, linseed oil and rosehip seed oil. ln a preferred embodiment, the vegetable oil is selected from the group consisting of rapeseed oil, sunflower oil and linseed oil, preferably selected from the group consisting of sunflower oil and linseed oil. A particular illustrative example of a vegetable oil that could be used according to the invention is linseed oil. Another particular example of a vegetable oil that could be used according to the invention is sunflower oil.

The oil, such as vegetable oil, could be a processed oil. For instance, the oil could be a fractionated oil. ln such a case, the processing, such as fractionation, of the oil could be done to remove fractions that may othen/vise become rancid. ln another embodiment, a mixture of multiple oils comprising at least one polymerized fatty acid is distributed within the at least a portion of the cellulose and/or lignocellulose ﬁber matrix. ln this embodiment, the multiple oils can be selected among the above mentioned examples. ln an embodiment, the cellulose and/or lignocellulose fiber matrix also comprises at least one binder, preferably at least one polymer binder and more preferably at least one thermoplastic polymer binder. Such a binder may then be included to bind the cellulose and/or lignocellulose fibers together to form the cellulose and/or lignocellulose ﬁber matrix. ln an embodiment, the binder may also assist in building up the foam-like structure of the cellulose and/or lignocellulose ﬁber matrix.

The binder, in particular polymer binders, such as thermoplastic polymer binders, may be intermingled with the cellulose and/or lignocellulose ﬁbers air-lying process to form the cellulose and/or lignocellulose ﬁber matrix. The binder may be added in the form of a powder, but is more often added in the form of ﬁbers that are intermingled with the cellulose and/or lignocellulose fibers in the air-laying process. Alternatively, or in addition, the binder may be added as solution, emulsion or dispersion into and onto the cellulose and/or lignocellulose ﬁber matrix.

The binder could be a natural or synthetic polymer binder, or a mixture of natural polymer binders, a mixture of synthetic polymer binders, or a mixture of natural and synthetic polymer binders, but is preferably a thermoplastic polymer binder. ln an embodiment, the binder is made from i) a material selected from the group consisting of polyethylene (PE), ethylene acrylic acid copolymer (EAA), ethylene-vinyl acetate (EVA), polypropylene (PP), polystyrene (PS), such as styrene-butadiene rubber (SBR) or styrene acrylate copolymer, polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polylactic acid (PLA), polyethylene terephthalate (PET), polycaprolactone (PCL), polyvinyl alcohol (PVA), polyethylene glycol (PEG), poly(2-ethyl-2-oxazoline) (PEOX), polyvinyl ether (PVE), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyvinyl acetate (PVAc), polyurethane (PU) and copolymers thereof and/or mixtures thereof, and ii) optionally one or more additives. ln an embodiment, the binder is a thermoplastic polymer binder and preferably selected from the group consisting of a thermoplastic polymer powder, thermoplastic polymer ﬁbers and a combination thereof. ~s.\.\=\,.\¿.\ . _ u u p t \\ . mo Q Qåw um.- _.

An air-laid substrate or material, such as in the form of an air-laid blank, sometimes also referred to as, dry-laid blank, air-laid mat, dry-laid mat, air-laid web or dry-laid web, is formed by a process known as air-laying, in which cellulose and/or lignocellulose fibers, and optionally a binder, such as a polymer binder, are mixed with air to form a porous ﬁber mixture deposited onto a support and consolidated or bonded by heating or thermoforming. This air-laid substrate is characterized by being porous, having the character of an open cell foam and being produced in a so-called dry forming method, i.e., generally without addition of water. The air-laying process was initially described in U.S. patent no. 3,575,749. The air-laid substrate may be in the form as produced in the air-laying process.

An example of an air-laid substrate that can be used according to the invention is such substrates made from a ﬂuff pulp material in an air-laying process.

The :I-air-laid substrate may be in the form of a single-layer cellulose and/or lignocellulose substrate or may be in the form of a multi-layer cellulose and/or lignocellulose substrate comprising lzsmultiple layers of cellulose and/or Iignocellulose materials, such as multiple layers of air-laid substrates.

The composite product of the present invention ﬁnds uses in many different applications where there is a need for an environmentally friendly composite that is resistant against absorption of moisture, liquid and/or grease. lllustrative, but non-limiting examples, include various three-dimensional (3D) construction elements, parts used in the automotive industry, such as instrument panels, interior elements in vehicles, door panels, etc., furniture, among others.

Another aspect of the invention relates to a composite jçigsubstrate comprising a cellulose and/or Iignocellulose ﬁber matrix and at least one polymerizable fatty acid or an oil or oil mixture comprising at least one polymerizable fatty acid. ln this aspect, the at least one polymerizable fatty acid or the oil or oil mixture is distributed within at least a portion of the cellulose and/or Iignocellulose ﬁber matrix. The at least a portion of the cellulose and/or Iignocellulose ﬁber matrix extends from a first surface of the cellulose and/or Iignocellulose fiber matrix to a second, opposite surface of the cellulose and/or Iignocellulose ﬁber matrix.

The composite product of the invention can be formed by polymerizing the at least one polymerizable fatty acid or the oil or oil mixture comprising the at least one polymerizable fatty acid distributed within rä the at least a portion of the cellulose and/or Iignocellulose ﬁber matrix of the composite gt substrate to obtain the at least one polymerized fatty acid or the oil or oil mixture comprising the at least one polymerized fatty acid distributed within at least a portion of the cellulose and/or Iignocellulose fiber matrix of the composite product. ln an embodiment, the composite "íwsubstrate may be subject to a forming operation prior to polymerizing the at least one polymerizable fatty acid. lllustrative, but non-limiting, examples of such forming operations include cutting, pressing, folding, thermoforming, wet molding and/or dry molding.

The composite substrate according to this aspect comprising at least one polymerizable fatty acid or an oil or oil mixture comprising at least one polymerizable fatty acid distributed within at least a portion of the composite substrate can be used to produce a composite product according to the present invention by exposing the composite "substrate or at least the portion thereof comprising the at least one polymerizable fatty acid or an oil or oil mixture to polymerizing conditions to form atleast one polymerized fatty acid or an oil or oil mixture comprising at least one polymerized fatty acid distributed within at least a portion of the so formed composite product. ln an embodiment, the at least one polymerizable fatty acid or the oil or oil mixture is distributed within a complete thickness of the at least a portion of the cellulose and/or lignocellulose fiber matrix of the compositegggi ïsubstrate. ln an embodiment, the at least one polymerizable fatty acid or the oil or oil mixture is homogenously distributed within the at least a portion of the cellulose and/or lignocellulose fiber matrix of the composite ïcsubstrate. ln an embodiment, the at least a portion of the cellulose and/or lignocellulose fiber matrix of the compositengggš " substrate is at least partly saturated with the at least one polymerizable fatty acid or the oil or oil mixture. ln an embodiment, the at least one polymerizable fatty acid or the oil or oil mixture is distributed within the cellulose and/or lignocellulose fiber matrix of the composite substrate. ln an embodiment, the cellulose and/or lignocellulose fibers are cellulose and/or lignocellulose pulp fibers produced by chemical, mechanical and/or chemi-mechanical pulping of softvvood and/or hardwood. ln a particular embodiment, the cellulose and/or lignocellulose fibers are cellulose and/or lignocellulose pulp fibers in a form selected from the group consisting of sulfate pulp, sulﬁte pulp, dissolving pulp, TMP, HTMP, MDF-ﬁber, CTMP, HTCTMP, and a combination thereof. ln an embodiment, the oil is a vegetable oil or the oil mixture is a mixture of vegetable oils. ln a particular embodiment, the vegetable oil is preferably selected from the group consisting of ﬂaxseed oil, avocado oil, sesame oil, safﬂower oil, sunﬂower oil, grapeseed oil, rapeseed oil, linseed oil and rosehip seed oil. For instance, the oil is linseed oil or the oil mixture is a mixture of linseed oil and at least one other vegetable oil. ln an embodiment, the composite gígjgsubstrate further comprises at least one binder, preferably at least one polymer binder and more preferably at least one thermoplastic polymer binder.ln a particular embodiment, the binder is made from i) a material selected from the group consisting of PE, EAA, EVA, PP, PS, such as SBR or styrene acrylate copolymer, PBAT, PBS, PLA, PET, PCL, PVA, PEG, PEOX, PVE, PVP, PAA, PMAA, PVAc, PU and copolymers thereof and/or mixtures thereof, and ii) optionally one or more additives.

The composite product and substrate 20 may optionally comprise one or more additives traditionally employed when manufacturing ce||u|ose and/or |ignoce||u|ose ﬁber matrices. These additives should then be compatible with the at least one polymerizable fatty acid or the oil or oil mixture and should preferably not signiﬁcantly interfere with polymerization of the at least one polymerizable fatty acid.

The composite product of the invention can be formed from the composite åjgmsubstrate by polymerizing the at least one polymerizable fatty acid to form the composite product comprising at least one polymerized fatty acid or an oil or oil mixture comprising at least one polymerized fatty acid distributed within at least a portion of the ce||u|ose and/or |ignoce||u|ose fiber matrix of the composite product.

The result of the polymerization is fatty acid based polymers, including fatty acid dimers, fatty acid trimers and/or longer fatty acid based polymers. lf multiple different polymerizable fatty acids are distributed within at least a portion of the ce||u|ose and/or |ignoce||u|ose fiber matrix of the composite n gjïwsubstrate, such as in the form of a mixture of polymerizable fatty acids or an oil or oil mixture, the resulting fatty acid based polymers may be in the form of co-polymers of different fatty acid monomers. The at least one polymerizable fatty acid or the oil or oil mixture becomes hardened during the polymerization and forms a solid hydrophobation and grease protection within the at least a portion of the ce||u|ose and/or |ignoce||u|ose fiber matrix of the composite product.

Polymerization of the at least one polymerizable fatty acid may, in an embodiment, take place in an oxygen containing atmosphere. The at least one polymerizable fatty acid can thereby be polymerized in ambient air without any particular treatment. However, such a polymerization generally takes quite a long time and would be most suited if the polymerization is allowed to proceed while the ce||u|ose product is stored, i.e., during its shelf life, or transport of the composite product. lt is, however, generally preferred to accelerate the polymerization of the at least one polymerizable fatty acid by treating thecomposite ï___substrate or at least a portion thereof. Illustrative, but non-Iimiting examples, of such polymerization accelerating treatments include heat treatment, ultraviolet (UV) light treatment, oxygen treatment (partial pressure of oxygen above 0.21 bar) and using polymerization catalysts. These various polymerization accelerating treatments may also be combined.

The heat treatment applied to the composite gšggïlwsubstrate or at least a portion thereof preferably involves heating the composite §5ç§__substrate or at least a portion thereof at a sufﬁcient temperature to accelerate the polymerization but not at too high temperature to degrade the composite substrate. As an illustrative, but non-Iimiting example, the composite substrate or at least a portion thereof could be heated to a temperature up to but not exceeding 210°C, preferably up to but not exceeding 190°C.

Illustrative, but non-Iimiting, examples of polymerization catalysts that could be used according to the invention include cobalt(ll) 2-ethylhexanoate and oil drying agent, also referred to as siccatives.

The polymerization of the at least one polymerizable fatty acid or the oil or oil mixture does not necessarily have to be in the form of a so-called oxypolymerization but could instead be in the form of condensation polymerization or radical polymerization of the at least one polymerizable fatty acid or the oil or oil mixture.

The at least one polymerizable fatty acid or the oil or oil mixture comprising at least one polymerizable fatty acid may be applied to the cellulose and/or lignocellulose ﬁber matrix of the composite ' substrate or a portion thereof according to various embodiments.

For instance, the at least one polymerizable fatty acid or the oil or oil mixture could be sprayed onto the cellulose and/or lignocellulose ﬁber matrix, or a portion thereof. ln such a case, a sufficient amount of the at least one polymerizable fatty acid or the oil or oil mixture is preferably sprayed onto the cellulose and/or lignocellulose fiber matrix or the portion thereof to allow the at least one polymerizable fatty acid or the oil or oil mixture to penetrate into the cellulose and/or lignocellulose fiber matrix sand thereby become distributed within the cellulose and/or lignocellulose fiber matrix or the portion thereof. ln another example, the at least one polymerizable fatty acid or the oil or oil mixture could be poured onto the cellulose and/or lignocellulose ﬁber matrix or the portion thereof. A further example is to immerse at least a portion of the cellulose and/or lignocellulose ﬁber matrix into the least one polymerizable fatty acid or the oil or oil mixture. Hence, in this embodiment, the cellulose and/or lignocellulose ﬁber matrix or the portion thereof is immersed in a bath of the at least one polymerizable fatty acid or the oil or oil mixture to soak the cellulose and/or lignocellulose ﬁber matrix or the portion thereof with the at least one polymerizable fatty acid or the oil or oil mixture. lt is also possible to combine two or more of the above described examples of applying the at least one polymerizable fatty acid or the oil or oil mixture.

The at least one polymerizable fatty acid or the oil or oil mixture is preferably applied in a sufficient quantity to the cellulose and/or lignocellulose fiber matrix to achieve a hydrogçggšobation and grease proofing effect for at least a portion of the cellulose and/or lignocellulose fiber matrix following polymerization.

The amount of polymerizable fatty acid or oil or oil mixture applied depends, among others, on the volume of the at least a portion of the cellulose and/or lignocellulose ﬁber matrix, to which the at least one polymerizable fatty acid or the oil or oil mixture is to be applied, the type of polymerizable fatty acid or oil or oil mixture, the type of material of the cellulose and/or lignocellulose ﬁber matrix, whether any processing has been applied to the polymerizable fatty acid or oil or oil mixture prior to application and whether any forming operations have been applied to the cellulose and/or lignocellulose ﬁber matrix prior to application.

The embodiments described above are to be understood as a few illustrative examples of the present invention. lt will be understood by those skilled in the art that various modiﬁcations, combinations and changes may be made to the embodiments without departing from the scope of the present invention. ln particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible.

Claims

1. A composite product (10) comprising a cellulose and/or Iignocellulose fiber matrix (20) in the form of an air-laid material and at least one polymerized fatty acid or an oil or oil mixture comprising at least one polymerized fatty acid, wherein the at least one polymerized fatty acid or the oil or oil mixture is distributed within at least a portion (22, 24) of the cellulose and/or Iignocellulose fiber matrix (20), wherein the at least a portion (22, 24) of the cellulose and/or Iignocellulose fiber matrix (20) extends from a first surface (21) of the cellulose and/or Iignocellulose fiber matrix (20) to a second, opposite surface (23) of the cellulose and/or Iignocellulose fiber matrix (20).

2. The composite product of claim 1, wherein the at least one polymerized fatty acid or the oil or oil mixture is distributed within a complete thickness (T, T1, T2) of the at least a portion (22, 24) of the cellulose and/or Iignocellulose ﬁber matrix (20).

3. The composite product of claim 1 or 2, wherein the at least one polymerized fatty acid or the oil or oil mixture is homogenously distributed within the at least a portion (22, 24) of the cellulose and/or Iignocellulose ﬁber matrix (20).

4. The composite product of any one of claims 1 to 3, wherein the at least a portion (22, 24) of the cellulose and/or Iignocellulose ﬁber matrix (20) is saturated with the at least one polymerized fatty acid or the oil or oil mixture.

5. The composite product of any one of claims 1 to 4, wherein the at least one polymerized fatty acid or the oil or oil mixture is distributed within the complete cellulose and/or Iignocellulose ﬁber matrix (20).

6. The composite product of any one of claims 1 to 5, wherein the cellulose and/or Iignocellulose matrix (20) comprises cellulose and/or Iignocellulose pulp fibers produced by chemical, mechanical and/or chemi-mechanical pulping of softvvood and/or hardwood.

7. The composite product of claim 6, wherein the cellulose and/or Iignocellulose pulp ﬁbers are cellulose and/or Iignocellulose pulp ﬁbers in a form selected from the group consisting of sulfate pulp, sulﬁte pulp, dissolving pulp, thermomechanical pulp (TMP), high temperature thermomechanical pulp (HTMP), mechanical ﬁber intended for medium density fiberboard (MDF-fiber), chemi-thermomechanical pulp (CTMP), high temperature chemi-thermomechanical pulp (HTCTMP), and a combination thereof.

8. The composite product of any one of claims 1 to 7, wherein the oil is a vegetable oil or the oil mixture is a mixture of vegetable oils; and the vegetable oil is preferably selected from the group consisting of flaxseed oil, avocado oil, sesame oil, safﬂower oil, sunﬂower oil, grapeseed oil, rapeseed oil, linseed oil and rosehip seed oil.

9. The composite product of claim 8, wherein the oil is linseed oil or the oil mixture is a mixture of linseed oil and at least one other vegetable oil.

10. The composite product of any one of claims 1 to 9, wherein the cellulose and/or lignocellulose fiber matrix (20) comprises at least one binder, preferably at least one polymer binder and more preferably at least one thermoplastic polymer binder.

11. The composite product of claim;;;--_\10, wherein the binder is made from i) a material selected from the group consisting of polyethylene (PE), ethylene acrylic acid copolymer (EAA), ethylene-vinyl acetate (EVA), polypropylene (PP), polystyrene (PS), such as styrene-butadiene rubber (SBR) or styrene acrylate copolymer, polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polylactic acid (PLA), polyethylene terephthalate (PET), polycaprolactone (PCL), polyvinyl alcohol (PVA), polyethylene glycol (PEG), poly(2-ethyl-2-oxazoline) (PEOX), polyvinyl ether (PVE), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyvinyl acetate (PVAc), polyurethane (PU) and copolymers thereof and/or mixtures thereof, and ii) optionally one or more additives.

12. A composite air-laid substrate f àsgggcomprising a cellulose and/or lignocellulose fiber matrix and at least one polymerizable fatty acid, or an oil or oil mixture comprising at least one polymerizable fatty acid, wherein the at least one polymerizable fatty acid or the oil or oil mixture is distributed within at least a portion of the cellulose and/or lignocellulose ﬁber matrix wherein the at least a portion of the cellulose and/or lignocellulose fiber matrix extends from a first surface of the cellulose and/or lignocellulose fiber matrix to a second, opposite surface of the cellulose and/or lignocellulose fiber matrix.