Packaging material and method for producing such material

Abstract

The present invention relates to an expandable granule comprising a lignocellulosic material and one or more expandable and / or pre-expanded particles, and optionally lightweight particles, and optionally one or more binders. The expandable granules have a density of about 0.05 to about 0.8 g / cm. 3 and is suitable for packaging applications. The invention also relates to a method for producing said granules and to the use of said granules, for example in packaging applications.

Description

[Technical Field]

[0001] The present invention relates to granules suitable for use in packaging, to methods for their production and to the use of said granules, for example in packaging applications. [Background technology]

[0002] The use of expanded polystyrene (EPS) or expanded polypropylene (EPP) for packaging and their manufacturing methods have been described previously, however these foams and / or moldings are still based on raw materials derived from fossil resources, such as petroleum.

[0003] Additionally, EPS can be used as packaging and / or packaging material, and in disposable products such as disposable cups. Annual production of EPS reaches millions of tons worldwide, with approximately 60% of it used in packaging and disposable products. Only a small fraction of these products are recycled, and some estimates suggest that some landfills may contain 25-35% EPS by weight.

[0004] European Patent Application Publication No. 0752444 describes a moldable pulp material useful for producing environmentally friendly cushioning packaging for electrical equipment as an alternative to polystyrene foam packaging. In this process, 1-5% by weight of thermally expandable hollow particles is mixed with pulp and a starch binder in water. The mixture is then filled into a mold assembly and compressed and heated to produce a molded pulp product.

[0005] WO 0154988 describes a low-density paperboard article useful as an insulating container that does not use EPS. The method includes providing a papermaking stock containing cellulose fibers and about 0.25 to about 10 weight percent expandable microspheres on a dry basis, preferably about 5 to about 7 weight percent, and forming a paperboard web from the papermaking stock on a papermaking machine. The density is described as being 6.0 to about 10 pounds per 3 MSF per mil.

[0006] Therefore, the use of fossil resources in the raw materials is minimized, it is recyclable, and at the same time, it is a material that is easy to handle and mold, and at the same time, it has a density of about 0.05 to about 0.8 g / cm 3 There is a need for a material useful for packaging that provides a reasonable density. Summary of the Invention

[0007] The present invention, according to a first aspect, solves / mitigates one or more of the above-mentioned problems by providing an expandable granule comprising lignocellulosic material, one or more expandable particles and / or pre-expanded particles, optionally lightweight particles, and optionally also one or more binders, wherein the expandable granule has a density of from about 0.05 to about 0.8 g / cm 3 , preferably about 0.1 to about 0.8 g / cm 3 The expandable granules may comprise 95% or more by weight of biopolymer material (including lignocellulosic material).

[0008] The present invention also provides, according to a second aspect, a method for producing expandable granules, comprising the steps of: a) providing a lignocellulosic material, preferably cellulose fibers; and b) providing expandable particles and / or lightweight particles, and mixing said lignocellulosic material with said particles (preferably including the additional step of adding a binder), thereby providing a granule.

[0009] The present invention also provides, according to a third aspect, a granule obtainable by the method according to the second aspect.

[0010] The present invention also provides, according to a fourth aspect, the use of granules according to the first or third aspect in the manufacture of a foam material, such as a cushioning material, or in an insulating material for building structures, or in an insulating material for keeping hot or cold food or ingredients warm, for example as an environmentally friendly cushioning packaging material that can be recycled together with paperboard.

[0011] The present invention also provides, according to a fifth aspect, a method for producing a foamed product, preferably comprising less than about 5% fossil-derived polymer, comprising the steps of: i) providing one or more granules according to the first aspect, or one or more granules obtained by a method according to the second aspect, or one or more granules according to the third aspect; ii) loading the granules into a mold assembly and heating the material (preferably to about 50 to about 150°C, more preferably to about 50 to about 120°C, and most preferably to about 60 to about 100°C), thereby providing an expanded foamed product. Heating can also be performed, for example, in an oven or an autoclave, or a combination thereof.

[0012] The present invention also provides, according to a sixth aspect, a foamed product obtainable by a method according to the fifth aspect. [Brief explanation of the drawings]

[0013] [Figure 1-1] Figure 1a) shows a test on short fibres (birch fibres) for producing inflatable granules of the invention. Figure 1b) shows a test on long fibres (pine fibres) for producing inflatable granules of the invention. [Figure 1-2] Figure 1c) shows in a filling test expandable granules of the invention made with different types of fibre (birch in Figure 1c1), eucalyptus in Figure 1c2) and pine in Figure 1c3). [Figure 1-3] Figure 1d) shows expandable granules containing different types of binders. Figure 1e) shows photographs of expandable granules of the present invention before and after different pulp refiner (PFI) milling processes. Figure 1f) shows a method for combining wet wood fiber flakes and expandable microspheres, optionally with a binding agent ("binder"), to produce expandable granules. [Figure 2a] Figure 2a) shows a schematic diagram of a preferred embodiment of the expandable granules of the present invention. [Figure 2b]Figure 2b) shows a micrograph of a preferred embodiment of the expandable granules of the present invention. [Figure 3] Figure 3a) shows a photograph of the granulation of expandable granules in a high shear mixer. Figure 3b) shows a photograph of the drying of the granulated expandable granules in a fluidized bed dryer. Figure 3c) shows a photograph of the filling of the expandable granules into a mould before the filled mould is placed in an oven. Figure 3d) shows a photograph of the moulded material after 15 minutes in the oven. Figure 3e) shows the product obtained when the material is poured into a different, i.e. cylindrical, mould. [Figure 4] Figure 4a) shows the application of the expandable granules of the present invention at full scale, and Figure 4b) shows the removal of the molded (and expanded) product from the mold in a full scale test. [Figure 5] Figure 5a) shows a molded product made from an expandable granule of the present invention containing recycled fibers, while Figures 5b) and 5c) show molded products made from an expandable granule of the present invention containing rejected fibers. DETAILED DESCRIPTION OF THE INVENTION

[0014] According to a first aspect, the present invention provides an expandable granular material comprising lignocellulosic material, one or more expandable particles and / or pre-expanded particles, optionally other lightweight particles, and optionally one or more binders, wherein the expandable granular material has a density of about 0.05 to about 0.8 g / cm. 3 , preferably about 0.1 to about 0.8 g / cm 3 and preferably the fossil-derived polymer is present in an amount of less than 5% by weight.

[0015] It has surprisingly been found that such expandable granules are suitable for the production of foamable and expanded products, such as cushioning or insulating materials (e.g. for building structures or for keeping hot or cold food or ingredients warm).

[0016] The expanded granules can be placed in a mold of any suitable shape and heated to form a unit. During the application of heat, the expanded granules expand and simultaneously form into a unit. Due to the inclusion of lignocellulosic material, the resulting product can be recycled together with paperboard after use. The lignocellulosic material is also biodegradable and recyclable. Thus, the granules according to the first aspect provide a sustainable and recyclable packaging material that can further help society move toward building a circular bioeconomy.

[0017] The granules also allow packaging to be made using EPS molding equipment by substituting the granules for PS that is expanded into molded EPS. Therefore, costly adjustments to the equipment are not required when the granules are used in place of PS (e.g., (expanded) PS spheres). Furthermore, the size and bulk density of the expandable granules can be adjusted as needed, and the density of the resulting molded product can be adjusted as well.

[0018] The expandable granules according to the first embodiment comprise lignocellulosic material. The lignocellulosic material can be, in principle, any type of lignocellulosic material known to those skilled in the art. The term "lignocellulosic material" refers to the dry matter of plants, also known as lignocellulosic biomass. Lignocellulosic material is typically composed of two types of carbohydrate polymers (cellulose and hemicellulose) and an aromatic-rich polymer called lignin.

[0019] Preferably, the lignocellulosic material is cellulose fiber. The lignocellulosic material can be virgin material, or material that has already been recycled (e.g., recycled fiber), or reject material (e.g., reject fiber) (i.e., virgin material that has not passed a specific quality control process for other uses), or a combination thereof. It is preferred that the lignocellulosic material contains at least some recycled or reject material, and preferably is primarily (e.g., more than 50%, 70%, 80%, or 90% by weight) composed of recycled or reject material. Most preferably, the lignocellulosic material consists essentially of recycled or reject material.

[0020] According to a preferred embodiment of the first aspect, the cellulose fibers may be derived from hardwoods or softwoods, or a combination thereof, preferably hardwoods, such as birch or eucalyptus, or a combination thereof, and most preferably obtained by a chemical process. The cellulose fibers may be derived from groundwood pulp (grinding pulp), chemi-thermomechanical pulp (CTMP), such as BCTMP (i.e., bleached CTMP), thermo-mechanical pulp (TMP), kraft pulp, sulfate pulp, sulfite pulp, non-wood pulp, recycled pulp material (recycled fiber), paper and board pulp, and / or cardboard pulp, or a combination thereof. Most preferably, the cellulose fibers are obtained by a chemical process, such as in the production of CTMP or BCTMP. The cellulose fibers may be derived from bleached or unbleached pulp, or a combination thereof. The cellulose fibers may be derived from hardwoods (e.g., eucalyptus, beech, oak, birch) or softwoods (e.g., pine or spruce), or combinations thereof. Straw, reed, bamboo, and bagasse, or combinations thereof, are also viable raw materials in this context. Preferred sources are hardwoods, as mentioned above, with birch or eucalyptus, or combinations thereof, being particularly preferred.

[0021] The expandable granules according to the first embodiment further comprise one or more expandable particles and / or pre-expanded particles.

[0022] Throughout this specification, the terms "expandable particles" and / or "pre-expanded particles" are intended to encompass any expandable particle useful in the context of the present invention. Such particles can be any expandable particle that increases in volume when heated, for example. Such particles can be, for example, expandable microspheres. Examples of such expandable microspheres include those sold by Nouryon under the trade name Expancel® Microspheres.

[0023] These particles may be pre-expanded particles, i.e., expandable particles that are already partially expanded but not yet fully expanded and will expand further upon exposure to heat, e.g., hot gas, e.g., steam. The expandable and / or pre-expanded particles comprise a polymeric shell and a hollow core containing a blowing agent. Upon heating, the blowing agent within the expandable and / or pre-expanded particles increases its pressure, thereby expanding the polymeric shell and resulting in an expanded particle.

[0024] The expandable particles and / or pre-expanded particles are discrete particles, i.e., single particles separate from one another, having a single hollow core surrounded by a polymeric shell.

[0025] All known expandable microspheres, in particular all known expandable thermoplastic microspheres, such as those sold under the trademark Expancel®, as mentioned above, can be used in the granules of the present invention. The expandable thermoplastic microspheres can consist of fossil- or bio-based polymeric materials.

[0026] Useful expandable microspheres are disclosed in the literature, e.g., U.S. Pat. Nos. 3,615,972, 3,945,956, 4,287,308, 5,536,756, 6,235,800, 6,235,394, 6,509,384, 6,617,363, and 6,984,347; U.S. Patent Application Publication Nos. 2004 / 0176486 and 2005 / 0079352; European Patent Application Publication No. 4860 80, 1230975, 1288272, 1598-405, 1811007 and 1964903, WO 2002 / 096635, WO 2004 / 072160, WO 2007 / 091960, WO 2007 / 091961 and WO 2007 / 142593, and Japanese Patent Application Publication Nos. 1987-286534 and 2005-272633.

[0027] Suitable expandable thermoplastic microspheres typically have a thermoplastic shell made from a polymer or copolymer obtained by polymerizing various ethylenically unsaturated monomers. These monomers may be nitrile-containing monomers such as acrylonitrile, methacrylonitrile, alpha-chloroacrylonitrile, alpha-ethoxyacrylonitrile, fumaronitrile, or crotononitrile; acrylic acid esters such as methyl acrylate or ethyl acrylate; methacrylic acid esters such as methyl methacrylate, isobornyl methacrylate, or ethyl methacrylate; vinyl halides such as vinyl chloride; vinylidene halides such as vinylidene chloride; vinyl acetates such as vinyl acetate; styrenes such as styrene, halogenated styrenes, or alpha-methylstyrene; dienes such as butadiene, isoprene, and chloroprene; or other types of monomers such as vinylpyridine. Suitable monomers may be obtained from renewable sources and thus biobased, such as lactone-based monomers (e.g., WO 2019 / 043235), itaconic acid dialkyl ester monomers (e.g., WO 2019 / 101749), or tetrahydrofurfuryl (meth)acrylate monomers (e.g., WO 2021 / 198487 and WO 2021 / 198492). Mixtures of any of the above monomers may also be used.

[0028] In some embodiments, it is preferred that the expandable particles and / or pre-expanded particles include monomers derived from renewable sources.

[0029] The monomer for the polymer shell may be a crosslinked polyfunctional monomer, such as divinylbenzene, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 15 pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, It may be desirable to include one or more of the following crosslinking monomers: acrylate, pentaerythritol hexa(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, triallyl formal tri(meth)acrylate, allyl methacrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane triacrylate, tributanediol di(meth)acrylate, PEG#200 di(meth)acrylate, PEG#400 di(meth)acrylate, PEG#600 di(meth)acrylate, 3-acryloyloxyglycol monoacrylate, triacryl formal, or triallyl isocyanate, triallyl isocyanurate, etc. If present, such crosslinking monomers preferably constitute 0.1 to 1 wt. % and most preferably 0.2 to 0.5 wt. % of the total amount of monomers for the polymer shell.

[0030] Preferably, the polymer shell comprises 60 to 95 wt %, most preferably 70 to 85 wt %, of the total weight of the entire microsphere.

[0031] The softening temperature of the polymer shell usually corresponds to its glass transition temperature (Tg), and is preferably within the range of 50 to 250°C, or 70 to 230°C.

[0032] The blowing agent encapsulated within the microspheres is typically a liquid with a boiling point below the softening temperature of the thermoplastic polymer shell. The blowing agent, also known as a blowing agent or propellant, can be at least one hydrocarbon, such as n-pentane, isopentane, neopentane, n-butane, isobutane, n-hexane, isohexane, neohexane, n-heptane, isoheptane, n-octane, and isooctane, or any mixture thereof. Other hydrocarbon types, such as petroleum ether, and chlorinated or fluorinated hydrocarbons, such as methyl chloride, methylene chloride, dichloroethane, dichloroethylene, trichloroethane, trichloroethylene, and trichlorofluoromethane, can also be used. Particularly preferred blowing agents include at least one of isobutane, isopentane, isohexane, cyclohexane, isooctane, isododecane, and mixtures thereof.

[0033] The blowing agent suitably constitutes 5 to 40 wt. % of the total weight of the microspheres. The boiling point of the blowing agent at atmospheric pressure may be within a wide range, preferably -20 to 200°C, most preferably -20 to 150°C, and most preferably -20 to 100°C. The heat-expandable thermoplastic microspheres are heated to promote their expansion. The temperature at which the microspheres begin to expand is T Start The temperature at which maximum expansion occurs is called T max These are all determined at a temperature ramp rate of 20°C / min.

[0034] The heat-expandable microspheres used in the present invention are preferably heated to a T of 50 to 200°C, more preferably 70 to 180°C, and most preferably 70 to 150°C. Start The heat-expandable microspheres used in the present invention have a T of 70 to 300°C, preferably 80 to 250°C, and most preferably 100 to 200°C. max The expandable microspheres preferably have a volume average diameter of 1 to 500 μm, more preferably 5 to 100 μm, and most preferably 10 to 70 μm, measured using a laser light scattering method on a wet sample with a Malvern Mastersizer Hydro 2000 SM instrument.

[0035] T max By heating the microspheres to a temperature exceeding this range, it is usually possible to expand the microspheres to 2 to 5 times or more of their original diameter, and preferably to 3 to 5 times their original diameter. Pre-expanded particles can be produced from any of the expandable particles described above.

[0036] The presence of expandable particles and / or pre-expanded particles ensures that the expandable granules of the first aspect of the invention are expandable. According to a preferred embodiment, the expandable particles are heat-expandable thermoplastic microspheres or pre-expanded heat-expandable thermoplastic microspheres, or a combination thereof.

[0037] The granules themselves can, in principle, have any granular shape. However, it is preferred that the granules are essentially spherical. The size of the expandable granules themselves is also not limited in principle. However, considering their processability, it is desirable that the expandable granules have an average diameter of less than 10 mm, preferably less than 5 mm, more preferably less than 3 mm, and most preferably less than 2 mm. In some embodiments, the expandable granules have an average diameter of more than 0.01 mm, for example, more than 0.05 mm or more than 0.1 mm.

[0038] The average diameter of a granule can be determined by one skilled in the art using commonly known techniques, such as image analysis, e.g., microscopy. The average diameter of a plurality of granules can also be determined by one skilled in the art using commonly known techniques, such as image analysis, e.g., microscopy using a Malvern Mastersizer 2000, or dynamic light scattering.

[0039] In some embodiments, the expandable granules comprise less than 12 wt.%, preferably less than 10 wt.%, such as less than 8 wt.% or less than 7 wt.%, more preferably less than 5 wt.%, such as less than 4 wt.% or less than 3 wt.%, of one or more expandable particles and / or pre-expanded particles, the weight percentages being based on the total weight of the expandable granules.

[0040] In some embodiments, the expandable granules comprise more than 0.01 wt.%, preferably more than 0.1 wt.%, such as more than 0.2 wt.% or more than 0.5 wt.%, more preferably more than 1 wt.%, such as more than 1.5 wt.%, of one or more expandable particles and / or pre-expanded particles, the weight percentages being based on the total weight of the expandable granules.

[0041] Thus, in some embodiments, the amount of one or more expandable particles and / or pre-expanded particles in the expandable granule is 0.01 to 12 wt%, for example 0.1 to 10 wt%, preferably 0.5 to 7 wt%, more preferably 1 to 5 wt%, for example 1.5 to 4 wt%, the weight percentage being based on the total weight of the expandable granule.

[0042] In some embodiments, the expandable granules comprise 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, such as 85% by weight or more, most preferably 90% by weight or more, such as 92% by weight or more, or even 95% by weight or more, of lignocellulosic material, based on the total weight of the expandable granules.

[0043] In some embodiments, the expandable granules comprise 99.99% by weight or less, preferably 99.9% by weight or less, more preferably 99.5% by weight or less, such as 99% by weight or less or 98% by weight or less, and most preferably 97% by weight or less, such as 95% by weight or less, 92% by weight or less, or 90% by weight or less, of lignocellulosic material, based on the total weight of the expandable granules.

[0044] Thus, in some embodiments, the amount of lignocellulosic material in the expandable granules is 50 to 99.99 wt%, for example 70 to 99.9 wt% or 80 to 99 wt%, preferably 85 to 98 wt%, more preferably 90 to 97 wt%, the weight percentage being based on the total weight of the expandable granules.

[0045] In some embodiments, the weight ratio of lignocellulosic material to one or more expandable particles and / or pre-expanded particles in the expandable granules of the first aspect is preferably from 99.99 / 0.01 to 88 / 12, for example from 99.9 / 0.1 to 90 / 10, or from 99 / 1 to 90 / 10, or from 98 / 2 to 90 / 10, or from 95 / 5 to 90 / 10.

[0046] In some embodiments, it is preferred that the relative amount by weight of lignocellulosic material to one or more expandable particles and / or pre-expanded particles in the expandable granules is 5 / 1 (wt / wt) or more, preferably 7 / 1 (wt / wt) or more, more preferably 8 / 1 or more, and even more preferably 10 / 1 (wt / wt) or more.

[0047] In some embodiments, the relative amounts by weight of lignocellulosic material to one or more expandable particles and / or pre-expanded particles in the expandable granules is 100 / 1 (wt / wt) or less, preferably 90 / 1 (wt / wt) or less, more preferably 80 / 1 or less, and even more preferably 70 / 1 (wt / wt) or less.

[0048] The expandable granules may further include a binding agent (also referred to herein as a "binder"), which is typically a polymer and may improve the stability of the expandable granules, typically by providing additional adhesion between the lignocellulosic material and the one or more expandable and / or pre-expanded particles.

[0049] In principle, any known binder can be used, preferred are binders that are one or more polymers capable of forming hydrogen bonds with lignocellulosic materials (e.g., cellulose fibers).

[0050] In some embodiments, the binder is a naturally occurring polymer, preferably selected from the group consisting of starch (such as cold swelling starch), chitosan, lignin, and cellulose (such as carboxymethyl cellulose (CMC)), and any combination thereof, more preferably starch, and particularly preferably cationic starch, such as cold swelling cationic starch.

[0051] The CMC-based binder may have a mass of 1 to 1000 kDa, for example, 5 to 500 kDa or 10 to 200 kDa. The amount of the binder itself in the expandable granules is not limited. However, in some preferred embodiments, the amount of the binder in the expandable granules is 5 wt. % or less, for example, 4 wt. % or less, or 3 wt. % or less, preferably 2 wt. % or less, based on the total weight of the expandable granules.

[0052] In some preferred embodiments, the amount of binder in the expandable granules is 0.1 wt. % or more, such as 0.2 wt. % or more, or 0.5 wt. % or more, preferably 1 wt. % or more, based on the total weight of the expandable granules.

[0053] Thus, in some embodiments, the amount of binder in the expandable granules is 0.1 to 5 wt. %, for example 0.2 to 4 wt. %, preferably 0.5 to 3 wt. %, most preferably 1 to 2 wt. %, based on the total weight of the expandable granules.

[0054] The presence of at least some binder in the expandable granules of the present invention has the advantage of reducing dust formation during the manufacture, handling, and storage of the expandable granule aggregates. Furthermore, the binder may reduce the tendency of the expandable granule aggregates to stick together, for example, when stored for a period of time. Thus, the binder may improve the flowability and handling properties of the expandable granule aggregate (e.g., when filled into a mold). The binder may also improve the adhesion properties of the expandable granule aggregate when it is molded.

[0055] The expandable granules may further comprise lightweight particles. The lightweight particles are not limited, and in principle, any lightweight particles generally known to those skilled in the art may be included in the expandable granules of the present invention.

[0056] In some embodiments, the lightweight particles are lightweight fillers such as fumed silica, aerogel, fly ash and other porous ceramics, porous aluminum hydroxide or aluminum silicate, porous polymer beads, already fully expanded microspheres (such as fully expanded thermoplastic microspheres), or combinations thereof.

[0057] Lightweight particles are, for example, 0.5 g / cm 3 less than 0.3 g / cm 3 less than 0.15 g / cm 3 Lightweight particles have a density of less than 0.001 g / cm 3 , e.g., 0.005 g / cm 3 or 0.01g / cm 3 may have a minimum density of

[0058] The amount of lightweight particles themselves in the expandable granules is not limited, however, in some preferred embodiments, the amount of lightweight particles in the expandable granules is 10% by weight or less, for example 8% by weight or less, or 7% by weight or less, preferably 5% by weight or less, for example 3% by weight or less, based on the total weight of the expandable granules.

[0059] In some preferred embodiments, the amount of lightweight particles in the expandable granules is 0.1 wt. % or more, such as 0.2 wt. % or more, or 0.5 wt. % or more, preferably 1 wt. % or more, based on the total weight of the expandable granules.

[0060] Thus, in some embodiments, the amount of lightweight particles in the expandable granules is 0.1 to 10 wt. %, for example 0.2 to 8 wt. %, preferably 0.5 to 5 wt. %, and most preferably 1 to 3 wt. %, based on the total weight of the expandable granules.

[0061] The lightweight particles serve to reduce the average bulk density of the expandable granules and can be used to adjust the average bulk density of the expandable granules to a particular desired average bulk density.

[0062] The expandable granules may further contain gas traps, e.g., air traps, different from the gas (i.e., blowing agent) contained in the expandable or pre-expanded microspheres. These traps may further reduce the density of the expandable granules. Such additional gas traps, e.g., air traps, may be present in an amount of 50% by volume or less, e.g., 30% by volume or less, or 20% by volume or less, or 10% by volume or less, based on the total volume of the expandable granules.

[0063] In some embodiments, such additional gas traps, e.g., air traps, may be present in an amount of 0.01 to 50% by volume, e.g., 0.1 to 50% by volume, or 0.5 to 50% by volume, preferably 0.1 to 30% by volume, 1 to 30% by volume, or 2 to 20% by volume, based on the total volume of the expandable granular body.

[0064] Gas traps, eg, air traps, can be the result of the presence of pre-expanded or lightweight particles, as well as the result of the manufacturing process for the expandable particles.

[0065] For example, the expandable granules may include: (i) Lignocellulosic material in an amount of 50% by weight or more, preferably 70% by weight or more. (ii) one or more expandable particles and / or pre-expanded particles in an amount of 0.01 to 12% by weight, preferably 0.1 to 10% by weight. (iii) An optional binder in an amount of 5% by weight or less, preferably 4% by weight or less. (iv) optional lightweight particles in an amount of 10% by weight or less, preferably 8% by weight or less. Here, the total weight of the expandable granular material, preferably the sum of components (i) to (iv), is 100% by weight.

[0066] In a preferred embodiment, the expandable granules may include: (i) Lignocellulosic material in an amount of 70 to 98% by weight, preferably 80 to 95% by weight. (ii) one or more expandable particles and / or pre-expanded particles in an amount of 1 to 7% by weight, preferably 0.1 to 5% by weight. (iii) a binder in an amount of 0.1 to 5% by weight, preferably 0.2 to 4% by weight or less. (iv) optional lightweight particles in an amount of 10% by weight or less, preferably 8% by weight or less. Here, the total weight of the expandable granular material, preferably the sum of components (i) to (iv), is 100% by weight.

[0067] In a more preferred embodiment, the expandable granules may include: (i) Lignocellulosic material in an amount of 85 to 98% by weight, preferably 90 to 95% by weight. (ii) one or more expandable particles and / or pre-expanded particles in an amount of 1 to 7% by weight, preferably 1 to 5% by weight. (iii) An optional binder in an amount of 4% by weight or less, preferably 3% by weight or less. (iv) optional lightweight particles in an amount of 5% by weight or less, preferably 3% by weight or less. Here, the total weight of the expandable granular material, preferably the sum of components (i) to (iv), is 100% by weight.

[0068] In a particularly preferred embodiment, the expandable granules may comprise: (i) Lignocellulosic material in an amount of 85 to 98% by weight, preferably 90 to 95% by weight. (ii) one or more expandable particles and / or pre-expanded particles in an amount of 1 to 7% by weight, preferably 1 to 5% by weight. (iii) A binder, preferably starch, in an amount of 0.01 to 4% by weight, preferably 0.01 to 3% by weight. (iv) optional lightweight particles in an amount of 5% by weight or less, preferably 3% by weight or less. Here, the total weight of the expandable granular material, preferably the sum of components (i) to (iv), is 100% by weight.

[0069] The expandable granules may further comprise at least one coating on at least a portion of their surface. Preferably, the expandable granules are completely coated with at least one coating. In some embodiments, the expandable granules may further comprise at least two coatings, e.g., at least three coatings, on at least a portion of their surface. In some embodiments, the expandable granules are completely coated with at least two coatings, e.g., at least three coatings. Preferably, the expandable granules comprise two coatings, more preferably three coatings, on their surface.

[0070] The type of coating itself is not limited, and in principle, any suitable coating known to those skilled in the art can be used. In some embodiments, the coating is selected from any of the binders defined above and / or any of the expandable or pre-expanded microspheres defined above.

[0071] Any of the at least one coatings may individually be applied to an average thickness of from 1 μm to 3 mm, such as from 2 μm to 2 mm, or from 2 μm to 1 mm.

[0072] The expandable granules of the present invention have a density of about 0.05 to about 0.8 g / cm 3 , preferably about 0.1 to about 0.8 g / cm 3 , more preferably 0.1 to 0.7 g / cm 3 , for example, 0.1 to 0.6 g / cm 3 or 0.1 to 0.5 g / cm 3 It has a bulk density of

[0073] In some embodiments, the expandable granules comprise less than 10% by weight, preferably less than 5% by weight, even more preferably less than 3% by weight, and most preferably less than 2% by weight of one or more fossil-derived polymers. In some embodiments, the expandable granules are completely free of fossil-derived polymers.

[0074] According to a second aspect, the present invention provides a method for producing expandable granules, comprising the steps of: a) providing a lignocellulosic material, preferably cellulose fibers; and b) providing one or more expandable particles and / or pre-expanded particles, and optionally lightweight particles, and mixing said lignocellulosic material with said particles (preferably including the additional step of adding a binder).

[0075] The method according to the second aspect may produce an expandable granule according to the first aspect. Thus, the expandable granule and its physical characteristics (e.g., bulk density and average size), as well as its components (e.g., lignocellulosic material, one or more expandable particles and / or pre-expanded particles, optional binder, optional lightweight filler, and optional coating) may be the same as those described herein above in the context of the first aspect.

[0076] The method according to the second aspect comprises providing a lignocellulosic material and further providing one or more expandable particles and / or pre-expanded particles. The lignocellulosic material, as already described above in the context of the first aspect, preferably the lignocellulosic material, may be provided in any form, such as in dry or wet form.

[0077] According to a further preferred embodiment of the second aspect, the expandable particles and / or pre-expanded particles already described above in the context of the first aspect are provided as a dry or wet powder, or as particles in the form of a slurry, or in the form of a stable paint-like formulation or gel.

[0078] After providing the components, lignocellulosic material and one or more expandable particles and / or pre-expanded particles, the components are mixed. Mixing can be performed in any suitable mixing device that ensures uniform mixing of the components.

[0079] As a further step, the mixed components may be granulated, for example using any suitable granulator, to form granules. Typically, granulators use a certain pressure (optionally at a temperature above room temperature) to form the granules. However, it is possible that the bulk density of the resulting expandable granules may be higher than the maximum value that may be desired, for example 0.8 g / cm. 3 Care should be taken that the pressure used in the granulator is not too high, so as not to exceed T. Furthermore, when using high temperatures for granulation, care should also be taken that the temperature is not too high, so that the one or more expandable particles and / or pre-expanded particles do not begin to expand, or even completely expand, during the process of forming the granules. Thus, any high temperatures that may be used should be considered in accordance with the expansion properties (particularly T) of the particular one or more expandable particles and / or pre-expanded particles used. Start ) needs to be adjusted accordingly.

[0080] In some embodiments, the granulation is carried out using a high shear mixer. In some embodiments, the resulting granules after granulation are dried, for example in a fluidized bed dryer.

[0081] The method according to the second aspect may include the additional step of adding a binder, such as those described above in the context of the first aspect. The binder may be added to the mixture of lignocellulosic material and one or more expandable particles and / or pre-expanded particles, which are already mixed components. However, all three components (including the binder) may also be provided separately and then mixed together.

[0082] The method according to the second aspect may include the additional step of adding lightweight particles, such as those described above in the context of the first aspect. The lightweight particles may be added to the mixture of already mixed components, lignocellulosic material and one or more expandable particles and / or pre-expanded particles (optionally already including a binder). However, all three components (including the lightweight particles), or all four components (including the binder and the lightweight particles) may also be provided separately and then mixed together.

[0083] The weight ratio in which the lignocellulosic material and one or more expandable particles and / or pre-expanded particles, and optional binder and / or optional lightweight particles are provided and mixed is not, per se, limited. In some embodiments, the weight ratio of the lignocellulosic material and one or more expandable particles and / or pre-expanded particles is as described above in the context of the first aspect of the invention. In some embodiments, the absolute weight range in which the lignocellulosic material and one or more expandable particles and / or pre-expanded particles, and optional binder and / or optional lightweight particles are provided and mixed, based on the total weight of the expandable granules, is as described above in the context of the first aspect.

[0084] According to a preferred embodiment of the second aspect, the method for producing granules also comprises the additional step d) of adding a coating agent, which may be any of the coating agents already described above in the context of the first aspect of the invention and may be used in any amount.

[0085] According to a further preferred embodiment of the second aspect, the step d) of adding the coating agent is subdivided into at least two separate, consecutive steps: d1) of adding a first coating agent and d2) of adding a second coating agent. Of course, further steps may also be carried out, such as d3) of adding a third coating agent and, optionally, d4) of adding a fourth coating agent.

[0086] In each of the at least two coating agent addition steps, the added coating agent may be the same or different, and each coating agent addition step may form a different layer that can be cured individually or together.

[0087] d1) A first step of adding a first coating agent forms a first layer directly on the surface of the granules, then d2) A second step of adding a second coating agent forms a second layer on the first layer, then d3) A third step of adding a third coating agent forms a third layer on the second layer, etc. Preferably, at least three layers are formed on the granules.

[0088] According to a further preferred embodiment of the second aspect, the method for producing granules also comprises the additional step e) of drying the granules obtained using the previous step, for which any suitable drying device can be used, such as a fluidized bed dryer.

[0089] The present invention also provides, according to a third aspect, a granule obtainable by the method according to the second aspect.

[0090] The present invention also provides, according to a fourth aspect, the use of granules according to the first or third aspect in the manufacture of a foam material, such as a cushioning material, or in an insulating material for building structures, or in an insulating material for keeping hot or cold food or ingredients warm, for example as an environmentally friendly cushioning packaging material that can be recycled together with paperboard.

[0091] The present invention also provides, according to a fifth aspect, a method for producing a foamed product, preferably comprising less than about 5% by weight of a fossil-derived polymer, comprising the steps of: (i) providing one or more granules according to the first aspect, or one or more granules obtained by a method according to the second aspect, or one or more granules according to the third aspect; (ii) loading the granules into a mold assembly and heating the material (preferably to about 50-150°C, more preferably about 55-130°C, and most preferably about 60-120°C), thereby providing an expanded foamed product.

[0092] Heating can also be performed, for example, in an oven or an autoclave, or a combination thereof.

[0093] According to a preferred embodiment of the fifth aspect, in step (ii) hot steam is applied to expand the granules.

[0094] According to a preferred embodiment of the fifth aspect, the density of the final foamed product is from about 0.01 to about 0.5 g / cm 3 , preferably about 0.025 to about 0.5 g / cm 3 , for example, about 0.05 to about 0.5 g / cm 3 , or about 0.05 to about 0.3 g / cm 3 is.

[0095] According to a preferred embodiment, the product obtained in step (ii) may be subjected to a sintering process (iii). During such a sintering process, the product obtained in step (ii) is kept at a temperature of 50-150°C for a period of time, such as at least 1 minute, or at least 5 minutes, or at least 10 minutes, and up to 2 hours, or up to 1 hour. The sintering process may improve the stability and / or homogeneity of the product.

[0096] The present invention also provides, according to a sixth aspect, a foamed product obtainable by a method according to the fifth aspect.

[0097] With regard to the fourth aspect, i.e., the use of the granules according to the first or third aspect in the manufacture of foam materials, such as cushioning materials, or in insulating materials for building structures, or in insulating materials for keeping hot or cold food or ingredients warm, the cushioning material can be part of a helmet or other safety equipment. When used in the manufacture of insulating materials for keeping hot or cold food or ingredients warm, it can be part of a cooler box for keeping fish and / or other seafood (lobster, crayfish, shrimp, etc.) fresh. It can also be used as a tray for keeping fresh vegetables and fruits. When used as a material for building structures, it can be part of a building (such as a house) or furniture.

[0098] Preferred features of each aspect of the invention apply mutatis mutandis to the features of each other aspect.

[0099] The prior art documents described herein are incorporated to the fullest extent permitted by law.

[0100] The present invention will be further illustrated by the accompanying drawings in conjunction with the following examples, which are not intended to limit the scope of the invention in any way.

[0101] Embodiments of the present invention will now be described in more detail with the help of examples of embodiments and in conjunction with the accompanying drawings, whose sole purpose is to illustrate the invention and is not intended to limit its scope.

[0102] drawing

[0103] Figure 1 shows in Figures 1a) and 1b) tests on short and long fibers for producing the inflatable granules of the present invention. Figure 1b) shows that wet fibers from pine needles tend to clump together, as the longer fibers cause clumping. The length of the fibers is twice that of birch (see Figure 1a), which does not tend to clump together. Nevertheless, clumping is not harmful in itself to the inflatable granules of the present invention.

[0104] Figure 1c) shows expandable granules of the present invention made with different types of fibers (birch (Figure 1c1), eucalyptus (Figure 1c2), or pine (Figure 1c3)) in a packing test (the funnel represents the potential shape of a fairly specific mold). It can be seen that the birch- and eucalyptus-based expandable granules have better packing properties than the pine-derived expandable granules. These granules contain 93% by weight of the respective fiber, 5% by weight of expandable microspheres (available under the trade name Expancel (031DU40)), and 2% by weight of starch as a binder.

[0105] Figure 1d) shows expandable granules containing different types of binders, namely starch and different types of carboxymethylcellulose (CMC), namely cold water soluble starch, CMC 40 kDa, CMC 100 kDa, and CMC 250 kDa.

[0106] Figure 1e) shows photographs of the expandable granules of the present invention before and after different laboratory pulp refiner (PFI) mill treatments: reference (before treatment), after PFI 500 RPM (revolution per minute) (approximately 40 kWh / ton), after PFI 5000 RPM (approximately 400 kWh / ton), and after PFI 10000 RPM (approximately 800 kWh / ton), respectively.

[0107] Figure 1f) shows how wet wood fiber flakes (2-5 mm in size, 20-30 wt. % solids content based on the total weight of the wet wood fiber flakes) are combined (in the form of a wet paste) with expandable microspheres (available under the trade name Expancel 031WUF40), optionally with the addition of a binding agent ("binder"), to obtain a granule.

[0108] FIG. 2 shows a schematic diagram (FIG. 2a) and a micrograph (FIG. 2b) of a preferred embodiment of the expandable granules of the present invention (also referred to herein as "Granuler+"). FIG. 2a) depicts a core (1) comprising lignocellulosic fibers (10), expandable microspheres (11) and / or pre-expanded microspheres (12), lightweight filler (13), and optionally a binder, and a coating layer (2) comprising expandable microspheres (21) and / or pre-expanded microspheres (22), and a coating (23). The coating can be, for example, a binder as described above. FIG. 2b) shows a micrograph of such a Granuler+.

[0109] Figure 3 shows how the expandable granules of the present invention can be applied in the production of molded articles, such as packaging materials. This is further highlighted by Figure 3a) showing the granulation of the expandable granules in a high-shear mixer, Figure 3b) showing the drying of the granulated expandable granules in a fluidized-bed dryer, Figure 3c) showing the filling of the expandable granules into a mold before placing the filled mold in a 150°C oven, and Figure 3d) showing the molded material after 15 minutes in the oven. Figure 3e) shows the product obtained when the material (i.e., the expandable granules) is poured into a different mold, i.e., a cylindrical mold, after compacting and sintering.

[0110] Figure 4 shows in Figure 4a) the application of the expandable granules of the present invention at full scale, and in Figure 4b) the removal of the molded (and expanded) product from the mold in a full scale test.

[0111] FIG. 5 shows molded products made from expandable granules of the present invention containing recycled fibers (FIG. 5a) and rejected fibers (FIGS. 5b and 5c), respectively. [Example]

[0112] Example 1

[0113] Example 1a 92.5 wt% pine fiber (bleached kraft pulp), 5 wt% expandable microspheres (available as 031WUF40 from Nouryon), and 2.5 wt% CMC (available as Finnfix 30F from Nouryon, added as an aqueous solution) were mixed in a kitchen mixer with additional water to achieve a total solids content of 25 wt%.

[0114] The mixture was formed into granules using a high-shear granulator (Diosna P1-6 Laboratory Mixer, Figure 3a) as shown in the schematic diagram of Figure 1f). The granules were dried in a fluidized bed (module MINILAB RC, Diosna, Figure 3b) to 45% solids and analyzed by visual inspection, microscopy, and packing tests for flowability.

[0115] It was concluded that the long fibers from pine produced "hairy" non-spherical granules. Such non-spherical granules may be less suitable for certain complex mold shapes, such as those shown in Figure 3c. However, such non-spherical granules are, of course, still suitable for use in less complex mold shapes, such as bricks or cylinders. The granules produced in this example are shown in Figures 1b and 1c3.

[0116] Example 1b 92.5 wt% birch fiber (bleached kraft pulp), 5 wt% expandable microspheres (available as 031WUF40 from Nouryon), and 2.5 wt% CMC (available as Finnfix 30F from Nouryon, added as an aqueous solution) were mixed in a kitchen mixer with additional water to achieve a total solids content of 25 wt%.

[0117] The mixture was formed into granules using a high-shear granulator (Diosna, P1-6 Laboratory Mixer, Figure 3a) as shown in the schematic diagram of Figure 1f). The granules were dried in a fluidized bed (module MINILAB RC, Diosna, Figure 3b) to 45% solids and analyzed by visual inspection, microscopy, and packing tests for flowability.

[0118] It was concluded that birch-derived short fibers produced spherical granules with fairly smooth surfaces that could be filled into certain complex mold shapes for the production of molded EPS products. The granules produced in this example are shown in Figures 1a) and 1c3).

[0119] The granulate was filled into a mold (Figure 3c) which was then heated to about 150°C for 15 minutes. Figure 3d) also shows the resulting fused (or molded) material.

[0120] Example 1c 92.5 wt% eucalyptus fiber (bleached kraft pulp), 5 wt% expandable microspheres (available as 031WUF40 from Nouryon), and 2.5 wt% CMC (available as Finnfix 30F from Nouryon, added as an aqueous solution) were mixed in a kitchen mixer with additional water to achieve a total solids content of 25 wt%.

[0121] The mixture was formed into granules using a high-shear granulator (Diosna P1-6 Laboratory Mixer, Figure 3a) as shown in the schematic diagram of Figure 1f). The granules were dried in a fluidized bed (module MINILAB RC, Diosna, Figure 3b) to 45% solids and analyzed by visual inspection, microscopy, and packing tests for flowability.

[0122] It was concluded that eucalyptus-derived short fibers produced spherical granules with fairly smooth surfaces that could be filled into certain complex mold shapes for the production of molded EPS products. The granules produced in this example are shown in Figure 1c2).

[0123] Example 1d 94 wt. % birch fiber (bleached kraft pulp), 5 wt. % expandable microspheres (available as 031WUF40 from Nouryon), and 1 wt. % cold water soluble starch (available as Solbond PC 65L from SOLAM, added as an aqueous solution) were mixed in a kitchen mixer with additional water to achieve a total solids content of 25 wt. %.

[0124] The mixture was formed into granules using a high-shear granulator (Diosna, Figure 3a) as shown schematically in Figure 1f. The granules were dried in a fluidized bed (Diosna, Figure 3b) to 45% solids and analyzed by visual inspection, microscopy, and packing tests for flowability.

[0125] It was concluded that in this system, starch also acts as a binder, producing spherical granules from birch fiber (bleached kraft pulp) with fairly smooth surfaces that can be filled into certain complex mold shapes for the production of molded EPS products.

[0126] Example 1e 94 wt. % recycled pulp (i.e., recycled fiber), 5 wt. % expandable microspheres (available as 031WUF40 from Nouryon), and 1 wt. % cold water soluble starch (available as Solbond PC 65L from SOLAM, added as an aqueous solution) were mixed in a kitchen mixer with additional water to achieve a total solids content of 25 wt. %.

[0127] The mixture was formed into granules using a high-shear granulator (Diosna, Figure 3a) as shown schematically in Figure 1f. The granules were dried in a fluidized bed (Diosna, Figure 3b) to 45% solids and analyzed by visual inspection, microscopy, and packing tests for flowability.

[0128] It was concluded that recycled pulp produced spherical granules with fairly smooth surfaces that could be filled into certain complex mold shapes for the production of molded EPS products. Figure 5a) shows a molded part made from recycled pulp granules.

[0129] Example 1f 94 wt. % of rejected pulp (i.e., rejected fiber), 5 wt. % of expandable microspheres (available as 031WUF40 from Nouryon), and 1 wt. % of cold water soluble starch (available as Solbond PC 65L from SOLAM, added as an aqueous solution) were mixed in a kitchen mixer with additional water to achieve a total solids content of 25 wt. %.

[0130] The mixture was formed into granules using a high-shear granulator (Diosna, Figure 3a) as shown schematically in Figure 1f. The granules were dried to 45% dryness in a fluidized bed (Diosna, Figure 3b) and analyzed by visual inspection, microscopy, and packing tests for flowability.

[0131] It was concluded that the rejected pulp produced spherical granules with smooth surfaces that could be filled into certain complex mold shapes for the production of molded EPS products. Figures 5b and 5c show molded products made from the rejected pulp granules.

[0132] Example 2 Various CMCs (available as Finnfix products from Nouryon) with different morphologies and different molecular weights (40 kDa, 100 kDa, and 250 kDa) were investigated as potential binders and compared with cold-water soluble starch as a binder. The resulting granules, produced as described in Examples 1b and 1d above, exhibit different shapes, as can be seen in Figure 1d). The results indicate that the type of binder and its molecular weight influence the final morphology of the granules. The 100 kDa CMC (Finnfix 30F) has the best binding performance.

[0133] Example 3 Tests were conducted to grind birch fibers to different grades. Granules produced from birch fibers with different degrees of grinding are shown in Figure 1e. Even short birch fibers show some tendency to produce "hairy" granules. Grinding the fibers in a wet state (in an Escher Wyss lab grinder) allows for modification of the fiber length and surface, which in turn affects the granule morphology. Grinding birch fibers at 5000 rpm appears to have the best effect in producing granules with a spherical, smooth surface, which perform well in packing tests.

[0134] Example 4 The granules of Example 1c were spray-coated with a thin layer of 2.5 wt. % aqueous CMC solution without using a high-speed chopper in the granulator tool. Expandable microspheres (available as Expancel 031WUF40 from Nouryon) were then added while the granules were moving. Excessive microspheres were added to achieve a visible effect. The expandable microspheres were adsorbed onto the surface of the granules by the wet, sticky CMC, creating a core-shell granulation product with a coating of expandable microspheres on the surface. Figure 2a) shows a schematic representation of the core-shell principle, and Figure 2b) shows an SEM image of a cross section of such a core-shell granule.

[0135] Example 5 A recipe from a combination of Examples 1b, 2, and 3 was used to test larger-scale molding using equipment typically used to manufacture molded EPS. Full-scale testing in an EPS molding machine showed that the granules filled the mold and were well fused by the steam used to heat the material in the mold (Figures 4a and 4b). The following was confirmed: The material, i.e. the expandable granules of the invention, behaves in a similar manner to the way EPS is produced. This material can be filled into molds of various shapes. The granules expand and fuse together to form a single molded product. The molded product can be removed from the mold.

[0136] One or more release agents may also be involved to allow for relatively easy removal of the fused material from the tool (which may otherwise stick to the mold). The tool was filled with the expandable granules of the present invention (approximately 30-35 liters) and subsequently heated with hot steam, causing the granules to expand within the mold and fuse together into a molded article. Thus, a foamed product was produced from the expandable granules in a mold for producing molded EPS, according to the above-described process according to the fourth aspect of the present invention.

[0137] While various embodiments of the present invention have been described above, those skilled in the art will recognize additional minor modifications that fall within the scope of the present invention. The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. For example, any of the granules / compositions or methods listed above can be combined with other known methods. Other aspects, advantages, and modifications within the scope of the present invention will be apparent to those skilled in the art to which the present invention pertains.

Claims

1. 1. An expandable granule comprising a lignocellulosic material, one or more expandable particles and / or pre-expanded particles, optionally lightweight particles, and optionally also one or more binders, wherein the expandable granule has a density of from about 0.05 to about 0.8 g / cm ３ , preferably about 0.1 to about 0.8 g / cm ３ An expandable granular material characterized by having a bulk density of

2. 2. The expandable granule according to claim 1, wherein the expandable granule comprises less than 12% by weight, preferably less than 10% by weight, more preferably less than 5% by weight of the one or more expandable particles and / or pre-expanded particles.

3. 3. The expandable granules according to claim 1 or 2, wherein the expandable granules comprise at least 50% by weight of the lignocellulosic material, preferably at least 70% by weight, more preferably at least 80% by weight, and most preferably at least 90% by weight.

4. 4. Expandable granules according to any one of claims 1 to 3, wherein the weight ratio of the lignocellulosic material to the one or more expandable particles and / or pre-expanded particles is from 99.99 / 0.01 to 88 / 12.

5. 1. A method for producing expandable granules, comprising the steps of: a) providing a lignocellulosic material, preferably cellulose fibers; and b) providing one or more expandable particles and / or pre-expanded particles, and optionally lightweight particles, and mixing said lignocellulosic material with said particles (preferably including the additional step of adding a binder);

6. 6. The method for producing expandable granules according to claim 5, wherein the weight ratio of the lignocellulosic material to the one or more expandable particles and / or pre-expanded particles is from 99.99 / 0.01 to 88 / 12.

7. 7. A method for producing expandable granules according to claim 5 or 6, wherein the expandable particles are provided as a dry or wet powder, or as particles in the form of a slurry or gel.

8. 8. A method for producing expandable granules according to any one of claims 5 to 7, wherein the expandable particles are thermally expandable thermoplastic microspheres or thermally pre-expanded microspheres, or a combination thereof.

9. 9. A method for producing a granule according to any one of claims 5 to 8, wherein the binder of the additional step in step b) is one or more polymers capable of forming hydrogen bonds with cellulose fibres, preferably selected from the group consisting of starch, chitosan, carboxymethylcellulose and any combination thereof, most preferably starch, said polymer being added in an amount particularly preferably present in an amount of not more than about 2% by weight.

10. moreover, c) the additional step of adding a coating agent; and / or d) an additional step of drying the granulate obtained using the previous step; A method for producing the granules according to any one of claims 5 to 7, further comprising:

11. 11. A method for producing a granule according to any one of claims 5 to 10, further comprising the step of forming at least two layers, preferably at least three layers, on the granule.

12. The bulk density of the expandable granules is about 0.05 to about 0.8 g / cm ３ , preferably about 0.1 to about 0.8 g / cm ３ A method for producing a granular material according to any one of claims 5 to 11, wherein

13. 13. A method for producing granules according to any one of claims 5 to 12, wherein the granules are made essentially spherical.

14. 14. A method for producing granules according to any one of claims 5 to 13, wherein the cellulose fibres are derived from softwoods or hardwoods or a combination thereof, preferably hardwoods such as birch or eucalyptus, or a combination thereof, and most preferably obtained by a chemical process.

15. 15. A method for producing a granule according to any one of claims 5 to 14, wherein the granule comprises less than 5% by weight of one or more fossil-derived polymers.

16. Granules obtainable by the method according to any one of claims 5 to 15.

17. Use of the granules according to claim 1 or 16 in the manufacture of foam materials, such as cushioning materials, or insulating materials for building structures, or insulating materials for keeping hot or cold food or ingredients warm, for example environmentally friendly cushioning packaging materials that can be recycled together with paperboard.

18. 1. A method for producing a foamed product, preferably comprising less than about 5% by weight of a fossil-derived polymer, comprising the steps of: (i) providing one or more granules according to any one of claims 1 to 4, or one or more granules obtained by a method according to any one of claims 5 to 15, or one or more granules according to claim 16; (ii) loading the granules into a mold assembly and heating the material (preferably to about 50-150°C, more preferably to about 55-130°C, and most preferably to about 60-120°C), thereby providing an expanded foamed product.

19. 20. The method of claim 18, wherein in step (ii) steam is applied to expand the granules.

20. The density of the final foamed product is from about 0.025 to about 0.5 g / cm ３ , preferably about 0.025 to about 0.3 g / cm ３ 20. The method of claim 18 or 19, wherein

21. A foamed product obtainable by the method according to any one of claims 18 to 20.

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