Packaging material and manufacturing method thereof

Abstract

The present invention relates to expandable pellets comprising a lignocellulosic material and one or more expandable and / or pre-expanded pellets, and optionally lightweight pellets, optionally further comprising one or more binders wherein the expandable pellets have a bulk density of from about 0.05 to about 0.8 g / cm3, which expandable pellets are suitable for use in packages. The invention further relates to a method for producing said pellets and to the use of said pellets, for example in packaging applications.

Description

TECHNICAL FIELD

[0001] The present invention relates to a granulate suitable for packaging, a method for its manufacture and the use of said granulate, for example in packaging applications. BACKGROUND

[0002] The use and manufacture of expanded polystyrene (EPS) or expanded polypropylene (EPP) for packaging has been described previously. However, these foamed and / or moulded packaging still are based on raw materials originating from fossil resources, such as oil.

[0003] Furthermore, EPS can be used as a wrapping and / or packaging material and also for disposable products, such as disposable cups. The global annual production of EPS amounts to millions of tons, of which about 60% is used for packaging and disposable products. Only a small fraction of said products is recycled, and some even estimate that EPS can account for 25-35 wt.% in certain landfills.

[0004] EP 0752444 A1 describes a mouldable pulp material which can be used to produce environmentally friendly shock absorbing packaging as a replacement for polystyrene foam packaging for electrical appliances. In this method, 1 to 5 wt.% of heat expandable hollow particles are mixed with paper pulp and a starch binder in water. The mixture is filled into a mould assembly, compressed and heated to produce a moulded pulp product.

[0005] WO 0154988 A2 describes a low density paperboard article which does not use EPS, which can be used as an insulating container. The method comprises providing a papermaking furnish containing cellulosic fibres and about 0.25 to about 10% (preferably about 5 to about 7 wt.% on a dry basis) of expandable microspheres, and forming a paperboard web from the papermaking furnish on a papermaking machine. A density of 6.0 to about 10 lb / 3MSF / mil (pounds per 3 million square feet / mil) is mentioned.

[0006] Therefore, there is a need for a material which can be used for packaging, which can minimise the use of fossil resources for its raw materials, which can be recycled, while also providing a material which is easy to handle and mould, and which at the same time provides a reasonable density, such as a density of about 0.05 to about 0.8 g / cm 3 . SUMMARY

[0007] The present invention solves / relieves one or more of the above problems by providing an expandable granulate according to a first aspect, the granulate comprising a lignocellulosic material and one or more expandable particles and / or pre-expanded particles, and optionally lightweight particles, optionally further comprising one or more binders, wherein the bulk density of the expandable granulate is about 0.05 to about 0.8 g / cm 3 , preferably about 0.1 to about 0.8 g / cm .3 The expandable pellets can comprise at least 95 wt.% of biopolymer material (including lignocellulosic material).

[0008] The present invention also provides according to a second aspect a method of manufacturing expandable pellets, comprising the steps of:

[0009] a) providing a lignocellulosic material, preferably cellulosic fibres, and

[0010] b) providing expandable particles and / or lightweight particles and mixing the lignocellulosic material with the particles, preferably including an additional step of adding a binder, thereby obtaining pellets.

[0011] The present invention also provides according to a third aspect a pellet obtainable by the method of the second aspect.

[0012] The present invention also provides according to a fourth aspect the use of the pellets of the first or third aspect in the manufacture of a foamed material (e.g. a shock absorbing material), or an insulation material for a building structure, or an insulation material for insulating or cooling food or food ingredients (e.g. an environmentally friendly shock absorbing packaging material that can be recycled together with paperboard).

[0013] The present invention also provides according to a fifth aspect a method of manufacturing a foamed product, preferably comprising less than about 5 wt.% of fossil-based polymers, the method comprising the steps of:

[0014] i) providing one or more pellets according to the first aspect, or pellets obtained by the method of the second aspect, or one or more pellets according to the third aspect,

[0015] ii) filling the pellets into a mould assembly and heating the material, preferably to about 50 to about 150 °C, more preferably to about 50 to about 120 °C, most preferably to about 60 to about 100 °C, thereby providing an expanded foamed product.

[0016] The heating can further be performed, for example, in an oven or an autoclave or a combination thereof.

[0017] The present invention also provides according to a sixth aspect a foamed product obtainable by the method of the fifth aspect. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 a) shows tests using short fibres (birch fibres) for preparing the expandable pellets of the present invention.

[0019] Figure 1 b) shows tests using long fibres (pine fibres) for preparing the expandable pellets of the present invention.

[0020] Figure 1c) shows expandable granules of the invention prepared using different fibre types in a filling test; Figure 1 c1) birch wood in, Figure 1 c2) eucalyptus wood in, Figure 1 c3) pine wood in.

[0021] Figure 1 d) shows expandable granules comprising different types of binder.

[0022] Figure 1 e) shows pictures of expandable granules of the invention before and after being subjected to different laboratory pulp refiner (PFI) grinding processes.

[0023] Figure 1 f) shows a scheme for preparing expandable granules by combining wet wood fibre flakes with expandable microspheres and optionally a binder ("binder").

[0024] Figure 2 a) shows a schematic representation of a preferred embodiment of expandable granules of the invention, Figure 2 b) shows a micrograph thereof.

[0025] Figure 3 a) shows pictures of expandable granules being granulated in a high-shear mixer.

[0026] Figure 3 b) shows pictures of expandable granules being dried in a fluid bed dryer after granulation.

[0027] Figure 3 c) shows pictures of expandable granules being filled into a mould (before the filled mould is put into an oven).

[0028] Figure 3 d) shows pictures of the moulding material after 15 minutes of treatment in an oven.

[0029] Figure 3 e) shows the products obtained when the material is cast in different moulds (i.e. cylindrical moulds).

[0030] Figure 4 a) shows the application of expandable granules of the present application in full-scale application.

[0031] Figure 4 b) shows the release of the moulded (and expanded) product from the mould in a full-scale test.

[0032] Figure 5 a) shows a moulded product made from expandable granules of the invention, wherein the expandable granules comprise recycled fibres.

[0033] Figure 5 b) and Figure 5 c) shows a molded product made from the expandable pellets of the present invention, wherein the expandable pellets comprise rejected fibers. DETAILED DESCRIPTION

[0034] The present invention provides according to a first aspect an expandable pellet comprising lignocellulosic material and one or more expandable and / or pre-expanded particles, and optionally further lightweight particles, optionally further comprising one or more binders, wherein the bulk density of the expandable pellet is from about 0.05 to about 0.8 g / cm3 3 , preferably from about 0.1 to about 0.8 g / cm3 3 , preferably wherein the fossil-based polymers are present in an amount lower than 5 wt%.

[0035] It was surprisingly found that such expandable pellets are suitable for making foamable and foamed products, such as shock absorbing or insulating materials, for example for use in building structures or for use in insulating or cooling food or food ingredients. An amount of expandable pellets can be placed in a mold, which can have any suitable shape, and molded together by applying heat to form a molded product. During the application of heat, the expandable pellets expand and at the same time are molded together. Due to its content of lignocellulosic material, the resulting product can be recycled together with paperboard after use. The lignocellulosic material is further biodegradable and recyclable. Thus, the pellets according to the first aspect provide a sustainable and recyclable packaging material, which can contribute to society further moving towards creating a circular bioeconomy. Furthermore, the pellets enable the use of EPS forming equipment to manufacture packaging, wherein the pellets are used instead of polystyrene (PS), which is expanded into molded EPS. Thus, when using the pellets instead of PS (e.g. (expanded) PS beads), no expensive adjustments of the equipment are necessary. Furthermore, the size and bulk density of the expandable pellets and the density of the molded product obtained therefrom can be customized as desired.

[0036] The expandable pellets according to the first aspect comprise a lignocellulosic material. In principle, the lignocellulosic material can be any type of lignocellulosic material well known to the skilled person. The term “lignocellulosic material” refers to plant dry matter, also known as lignocellulosic biomass. Lignocellulosic material is typically composed of two carbohydrate polymers (cellulose and hemicellulose) and one aromatic-rich polymer called lignin. Preferably, the lignocellulosic material is a cellulose fiber. The lignocellulosic material can be virgin material or recycled material, such as recycled fiber, or waste material, such as waste fiber (i.e. material that is virgin but has not passed certain quality control steps by other applications), or a combination thereof. It is preferred that the lignocellulosic material comprises at least some recycled or waste material, and preferably comprises predominantly (e.g. more than 50 wt.%, more than 70 wt.%, more than 80 wt.-%, or more than 90 wt.%) recycled or waste material. Most preferably, the lignocellulosic material consists essentially of recycled or waste material.

[0037] According to a preferred embodiment of the first aspect, the cellulose fibers can be derived from softwood or hardwood or a combination thereof, preferably hardwood, such as birch or eucalyptus or a combination thereof, most preferably obtained by chemical means. The cellulose fibers can be derived from groundwood (groundwood pulp), chemi-thermo-mechanical pulp (CTMP) (e.g. BCTMP, i.e. bleached CTMP), thermomechanical pulp (TMP), kraft pulp, sulphate pulp, sulphite pulp, non-wood pulp, recycled pulp material (recycled fiber), pulp for paper and paperboard and / or for carton, or a combination thereof. Most preferably, the cellulose fibers are obtained by chemical means, such as when manufacturing CTMP or BCTMP. The cellulose fibers can be derived from bleached or unbleached pulp, or a combination thereof. The cellulose fibers can be derived from hardwood (e.g. eucalyptus, beech, oak, birch) or softwood (e.g. pine or spruce), or a combination thereof. Rice straw, reed, bamboo and sugar cane bagasse or a combination thereof are also feasible raw materials in this context. As mentioned above, a preferred source is hardwood; particularly preferred is birch or eucalyptus or a combination thereof.

[0038] The expandable pellets according to the first aspect further comprise one or more expandable particles and / or pre-expanded particles.

[0039] In this specification, the expressions “expandable particles” and / or “pre- expanded particles” are intended to encompass any expandable particles useful in the context of the present application. Such particles can be any expandable particles, i.e. particles whose volume increases upon heating, for example. Such particles can be, for example, expandable microspheres. An example of such expandable microspheres are Nouryon expandable microspheres under the trade name Expancel®. The expandable particles can be present in the expandable pellets according to the first aspect in an amount of 0.1 to 20 wt.-%, preferably 0.5 to 15 wt.-%, more preferably 1 to 10 wt.-%, most preferably 2 to 5 wt.-%, based on the total weight of the expandable pellets. Microspheres Microspheres sells microspheres. These particles can also be pre-expanded particles, i.e. expandable particles that have been partially expanded but not yet fully expanded, and that further expand upon being heated, e.g. by a hot gas such as steam. The expandable particles and / or pre-expanded particles comprise a polymeric shell and a hollow core containing a blowing agent. Upon heating, the blowing agent in the expandable particles and / or pre-expanded particles increases in pressure, causing the polymeric shell to expand, forming expanded particles. The expandable particles and / or pre-expanded particles are discrete particles, i.e. individual particles that are separate from one another, having a single hollow core surrounded by a polymeric shell.

[0040] All known kinds of expandable microspheres, in particular all known types of expandable thermoplastic microspheres, can be used in the granules according to the present application, for example the expandable microspheres sold under the trademark those sold. The expandable thermoplastic microspheres can be fossil-based or bio-based polymeric materials. Useful expandable microspheres are described in the literature, for example in U.S. Patent Nos. 3,615,972, 3,945,956, 4,287,308, 5,536,756, 6,235,800, 6,235,394, and 6,509,384, 6,617,363, and 6,984,347, in U.S. Patent Application Publications US 2004 / 0176486 and 2005 / 0079352, in EP 486080, EP 1230975, EP 1288272, EP 1598-405, EP 1811007, and EP 1964903, in WO 2002 / 096635, WO 2004 / 072160, WO 2007 / 091960, WO 2007 / 091961, and WO 2007 / 142593, and in Japanese Laid-Open Patent Publication Nos. 1987-286534 and 2005-272633. Suitable expandable thermoplastic microspheres generally have a thermoplastic shell made from a polymer or copolymer obtainable by polymerizing various ethylenically unsaturated monomers, which can be nitrile-containing monomers such as acrylonitrile, methacrylonitrile, a-chloroacrylonitrile, a-ethoxyacrylonitrile, fumaronitrile, or crotononitrile; acrylic esters such as methyl acrylate or ethyl acrylate; methacrylic esters such as methyl methacrylate, isobornyl methacrylate, or ethyl methacrylate; vinyl halides such as vinyl chloride; vinylidene halides such as vinylidene chloride; vinyl esters such as vinyl acetate; styrenes such as styrene, halogenated styrene, or a-methylstyrene; dienes such as butadiene, isoprene, and chlorobutadiene; or other types of monomers such as vinylpyridine. Suitable monomers can also be those that have been obtained from renewable sources and are thus bio-based, such as lactone-based monomers (e.g., in WO 2019 / 043235 Al), dialkyl itaconate monomers (e.g., in WO 2019 / 101749 Al), or tetrahydrofurfuryl (meth)acrylate monomers (e.g., in WO 2021 / 198487 Al and WO 2021 / 198492 Al). Any mixtures of the above monomers can also be used. In some embodiments, it is preferred that the expandable particles and / or pre-expanded particles comprise monomers from renewable sources.Sometimes, it can be desirable for the monomers of the polymer shell to further comprise a crosslinking multifunctional monomer, such as one or more of divinyl benzene, 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, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol hexa(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, triallyl formal tri(meth)acrylate, allyl methacrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane triacrylate, tributylene glycol di(meth)acrylate, PEG #200 di(meth)acrylate, PEG #400 di(meth)acrylate, PEG #600 di(meth)acrylate, 3-acryloyloxy ethylene glycol monoacrylate, tripropylene formal, or triallyl isocyanate, triallyl isocyanurate, and the like. If present, such crosslinking monomers preferably comprise 0.1 to 1 wt.%, most preferably 0.2 to 0.5 wt.% of the total amount of monomers of the polymer shell. Preferably, the polymer shell comprises 60 to 95 wt.%, most preferably 70 to 85 wt.% of the total weight of the microspheres. The softening temperature of the polymer shell (which generally corresponds to its glass transition temperature (Tg)) is preferably in the range of 50 to 250 °C, or in the range of 70 to 230 °C. The blowing agent encapsulated within the polymer shell in the microspheres is typically a liquid having a boiling point not higher than 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, isohexane, n-octane, and isooctane, or any mixture thereof. In addition, other types of hydrocarbons can also be used, such as petroleum ether, as well as chlorinated or fluorinated hydrocarbons, such as chloromethane, dichloromethane, dichloroethane, dichloroethylene, trichloroethane, trichloroethylene, trichlorofluoromethane, and the like. Particularly preferred blowing agents comprise at least one of isobutane, isopentane, isohexane, cyclohexane, isooctane, isododecane, and mixtures thereof. The blowing agent suitably comprises 5 to 40 wt.% of the total weight of the microspheres. The blowing agent can have a boiling point at atmospheric pressure in 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 cause them to expand. The temperature at which the microspheres start to expand is referred to as T 开始 , and the temperature at which maximum expansion is reached is referred to as T max , both determined at a temperature ramping rate of 20 °C per minute. The T 开始Suitably from 50 to 200°C, preferably from 70 to 180°C, most preferably from 70 to 150°C. The T max Suitably from 70 to 300°C, preferably from 80 to 250°C, most preferably from 100 to 200°C. The volume median diameter of the expandable microspheres is preferably from 1 to 500 pm, more preferably from 5 to 100 pm, most preferably from 10 to 70 pm, as determined by laser light scattering on a Malvern Mastersizer Hydro 2000SM instrument on a wet sample. By heating to a temperature above the T max The microspheres can typically be expanded to 2 to 5 times or more, preferably 3 to 5 times their original diameter by heating to a temperature above the T

[0041] The presence of expandable particles and / or pre-expanded particles ensures that the expandable granules of the first aspect of the present application are expandable. According to a preferred embodiment, the expandable granules are thermally expandable thermoplastic microspheres or pre-expanded thermally expandable thermoplastic microspheres, or a combination thereof.

[0042] The granules can in principle have any granule form. However, it is preferred that the granules are substantially spherical. The size of the expandable granules in itself is also not limited in principle. However, taking into account their processability, it is desirable that the average diameter of the expandable granules is 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 average diameter of the expandable granules is greater than 0.01 mm, for example greater than 0.05 mm or greater than 0.1 mm. The average diameter of a granule can be determined by the person skilled in the art using common techniques, for example image analysis, such as microscopy. The average diameter of a plurality of granules can also be determined by the person skilled in the art using common techniques, for example image analysis, such as microscopy, or dynamic light scattering methods, for example using a Malvern Mastersizer 2000.

[0043] In some embodiments, the expandable pellets comprise less than 12 wt.%, preferably less than 10 wt.%, such as less than 8 wt.% or less than 7 wt.%, and more preferably less than 5 wt.%, such as less than 4 wt.% or less than 3 wt.% of the one or more expandable particles and / or pre-expanded particles, the wt.% based on the total weight of the expandable pellets. In some embodiments, the expandable pellets 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.%, and more preferably more than 1 wt.%, such as more than 1.5 wt.% of the one or more expandable particles and / or pre-expanded particles, the wt.% based on the total weight of the expandable pellets. Thus, in some embodiments, the amount of one or more expandable particles and / or pre-expanded particles in the expandable pellets is from 0.01 to 12 wt.%, such as from 0.1 to 10 wt.%, preferably from 0.5 to 7 wt.%, and more preferably from 1 to 5 wt.%, such as from 1.5 to 4 wt.%; the wt.% based on the total weight of the expandable pellets.

[0044] In some embodiments, the expandable pellets comprise 50 wt.% or more, preferably 70 wt.% or more, more preferably 80 wt.% or more, such as 85 wt.% or more, and most preferably 90 wt.% or more, such as 92 wt.% or more or even 95 wt.% or more of the lignocellulosic material, the wt.% based on the total weight of the expandable pellets. In some embodiments, the expandable pellets comprise 99.99 wt.% or less, preferably 99.9 wt.% or less, more preferably 99.5 wt.% or less, such as 99 wt.% or less or 98 wt.% or less, and most preferably 97 wt.% or less, such as 95 wt.% or less, 92 wt.% or less or 90 wt.% or less of the lignocellulosic material, the wt.% based on the total weight of the expandable pellets. Thus, in some embodiments, the amount of lignocellulosic material in the expandable pellets is from 50 to 99.99 wt.%, such as from 70 to 99.9 wt.% or from 80 to 99 wt.%; preferably from 85 to 98 wt.%, and more preferably from 90 to 97 wt.%, the wt.% based on the total weight of the expandable pellets.

[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 from 99.99 / 0.01 to 88 / 12, such as 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. In some embodiments, it is preferred that the relative weight ratio of lignocellulosic material to one or more expandable particles and / or pre-expanded particles in the expandable granules is 5 / 1 (wt. / wt.) or higher, preferably 7 / 1 (wt. / wt.) or higher, more preferably 8 / 1 or higher, and even more preferably 10 / 1 (wt. / wt.) or higher. In some embodiments, the relative weight ratio of lignocellulosic material to one or more expandable particles and / or pre-expanded particles in the expandable granules is 100 / 1 (wt. / wt.) or lower, preferably 90 / 1 (wt. / wt.) or lower, more preferably 80 / 1 or lower, and even more preferably 70 / 1 (wt. / wt.) or lower.

[0046] The expandable granules can further comprise a binder (also referred to herein as a "bonding agent"). The binder is typically a polymer, and can improve the stability of the expandable granules by providing additional adhesion between the lignocellulosic material and the one or more expandable particles and / or pre-expanded particles. In principle any known binder can be used. Preferred binders are one or more polymers capable of forming hydrogen bonds with the lignocellulosic material, such as cellulose fibres.

[0047] In some embodiments, the binder is a polymer of natural origin, and is preferably selected from the group consisting of starch (such as cold-swell starch), chitosan, lignin, and cellulose (such as carboxymethyl cellulose (CMC)), and any combination thereof, more preferably is starch, and particularly preferably is cationic starch, such as cold-swell cationic starch. The CMC-based binder can have a mass of from 1 to 1000 kDa, such as from 5 to 500 kDa or from 10 to 200 kDa.

[0048] The amount of binder in the expandable granules is not limited. However, in some preferred embodiments, the amount of binder in the expandable granules is at most 5 wt.%, such as at most 4 wt.% or at most 3 wt.%, and preferably at most 2 wt.%, the wt.% being based on the total weight of the expandable granules. 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, and preferably 1 wt.% or more, the wt.% being based on the total weight of the expandable granules. Thus, in some embodiments, the amount of binder in the expandable granules is 0.1 to 5 wt.%, such as 0.2 to 4 wt.%, preferably 0.5 to 3 wt.%, and most preferably 1 to 2 wt.%, the wt.% being based on the total weight of the expandable granules.

[0049] The presence of at least some binder in the expandable granules of the present application has the advantage that potential dust formation during production, handling and storage of a quantity of expandable granules can be reduced. Furthermore, the binder can reduce the tendency of a quantity of expandable granules to stick together, for example after storage for a period of time. Thus, the binder can improve the flowability and handleability of a quantity of expandable granules, for example when filling into a mould. Furthermore, the binder can improve the fusion performance of a quantity of expandable granules when moulded.

[0050] The expandable granules can further comprise lightweight particles. The lightweight particles are not limited, and in principle any lightweight particle known to the person skilled in the art can be comprised in the expandable granules of the present application. In some embodiments, the lightweight particles are lightweight fillers, such as fumed silica, aerogels, fly ash and other porous ceramics, porous aluminium or aluminium silicate hydroxide, porous polymer beads, microspheres that have been fully expanded, such as fully expanded thermoplastic microspheres, or combinations thereof. The lightweight particles can have a density of, for example, less than 0.5 g / cm3, preferably less than 0.3 g / cm3, and more preferably less than 0.15 g / cm3. The lightweight particles can have a minimum density of, for example, 0.001 g / cm3, such as a minimum density of 0.005 g / cm3or a minimum density of 0.01 g / cm3. 3 3 3 The lightweight particles can have a minimum density of, for example, 0.001 g / cm3, such as a minimum density of 0.005 g / cm3or a minimum density of 0.01 g / cm3. 3 3 3

[0051] ​​​​​The amount of lightweight particles in the expandable granules per se is not limited. However, in some preferred embodiments, the amount of lightweight particles in the expandable granules is at most 10 wt.%, such as at most 8 wt.% or at most 7 wt.%, and preferably at most 5 wt.%, such as at most 3 wt.%, the wt.% being based on the total weight of the expandable granules. 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, and preferably 1 wt.% or more, the wt.% being based on the total weight of the expandable granules. Thus, in some embodiments, the amount of lightweight particles in the expandable granules is 0.1 to 10 wt.%, such as 0.2 to 8 wt.%, preferably 0.5 to 5 wt.%, and most preferably 1 to 3 wt.%, the wt.% being based on the total weight of the expandable granules.

[0052] The lightweight particles can help 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 certain desired average bulk density.

[0053] The expandable granules can further comprise gas entrapments, such as air entrapments, which are different from the gas (i.e. blowing agent) comprised in the expandable or pre-expanded microspheres. These entrapments can further reduce the density of the expandable granules. Such additional gas entrapments, such as air entrapments, can be present in an amount of at most 50 vol.%, such as at most 30 vol.% or at most 20 vol.%, or at most 10 vol.%, based on the total volume of the expandable granules. In some embodiments, such additional gas entrapments, such as air entrapments, can be present in an amount of 0.01 to 50 vol.%, such as 0.1 to 50 vol.% or 0.5 to 50 vol.%, preferably 0.1 to 30 vol.%, 1 to 30 vol.% or 2 to 20 vol.%, based on the total volume of the expandable granules. The gas entrapments, such as air entrapments, can be due to the presence of pre-expanded particles or lightweight particles, but can also be due to the manufacturing process of the expandable granules.

[0054] For example, the expandable granules can comprise:

[0055] (i) lignocellulosic material in an amount of 50 wt.% or more, preferably 70 wt.% or more;

[0056] (ii) one or more expandable particles and / or pre-expanded particles in an amount of 0.01 to 12 wt.%, preferably 0.1 to 10 wt.%;

[0057] (iii) optionally a binder in an amount of 5 wt.% or less, preferably 4 wt.% or less;

[0058] (iv) Optional lightweight particles, in an amount of 10 wt.% or less, preferably 8 wt.% or less.

[0059] The total weight of the expandable granules (preferably components (i)-(iv)) is 100 wt.%.

[0060] In a preferred embodiment, the expandable granules may comprise:

[0061] (i) a lignocellulose material, in an amount of 70-98 wt.%, preferably 80-95 wt.%;

[0062] (ii) One or more expandable particles and / or pre-expanded particles, in an amount of 1-7 wt.%, preferably 0.1-5 wt.%;

[0063] (iii) an adhesive, in an amount of 0.1-5 wt.%, preferably 0.2-4 wt.% or less;

[0064] (iv) Optional lightweight particles, in an amount of 10 wt.% or less, preferably 8 wt.% or less.

[0065] The total weight of the expandable granules (preferably components (i)-(iv)) is 100 wt.%.

[0066] In a more preferred embodiment, the expandable granules may comprise:

[0067] (i) a lignocellulose material, in an amount of 85-98 wt.%, preferably 90-95 wt.%;

[0068] (ii) One or more expandable particles and / or pre-expanded particles, in an amount of 1-7 wt.%, preferably 1-5 wt.%;

[0069] (iii) An optional adhesive, in an amount of 4 wt.% or less, preferably 3 wt.% or less;

[0070] (iv) Optional lightweight particles, in an amount of 5 wt.% or less, preferably 3 wt.% or less.

[0071] The total weight of the expandable granules (preferably components (i)-(iv)) is 100 wt.%.

[0072] In a particularly preferred embodiment, the expandable granules may comprise:

[0073] (i) a lignocellulose material, in an amount of 85-98 wt.%, preferably 90-95 wt.%;

[0074] (ii) one or more expandable particles and / or pre-expanded particles in an amount of 1-7 wt.%, preferably 1-5 wt.%;

[0075] (iii) a binder (preferably starch) in an amount of 0.01 to 4 wt.%, preferably 0.01 to 3 wt.%;

[0076] (iv) optionally light-weight particles in an amount of 5 wt.% or less, preferably 3 wt.% or less,

[0077] The sum of the total weight of the expandable granules (preferably components (i)-(iv)) is 100 wt.%.

[0078] The expandable granules can further comprise at least one coating on at least a portion of their surface. Preferably, the expandable granules are completely coated by at least one coating. In some embodiments, the expandable granules can further comprise at least two coatings, for example at least three coatings, on at least a portion of their surface. In some embodiments, the expandable granules are completely coated by at least two coatings, for example at least three coatings. Preferably, the expandable granules comprise two coatings on their surface, more preferably, the expandable granules comprise three coatings on their surface.

[0079] The type of the coating is not limited per se and in principle any suitable coating known to the person skilled in the art can be used. In some embodiments, the coating is selected from any binder as defined above and / or expandable microspheres or pre-expanded microspheres as defined above. Any of the at least one coating can independently be applied in an average thickness of 1 pm to 3 mm, for example in an average thickness of 2 pm to 2 mm or 2 pm to 1 mm.

[0080] The bulk density of the expandable granules of the present application is about 0.05 to about 0.8 g / cm3 3 , preferably about 0.1 to about 0.8 g / cm3 3 , more preferably 0.1 to 0.7 g / cm3 3 , for example 0.1 to 0.6 g / cm3 3 or 0.1 to 0.5 g / cm3 3 .

[0081] In some embodiments, the expandable granules comprise less than 10 wt.%, preferably less than 5 wt.%, even more preferably less than 3 wt.% and most preferably less than 2 wt.% of one or more fossil-based polymers. In some embodiments, the expandable granules are completely free of fossil-based polymers.

[0082] The present application provides according to a second aspect a method for manufacturing expandable granules comprising the following steps:

[0083] a) providing a lignocellulosic material (preferably cellulosic fibers); and b) providing one or more expandable particles and / or pre-expanded particles, and optionally lightweight particles, and mixing the lignocellulosic material with the particles, preferably including the additional step of adding a binder.

[0084] The method according to the second aspect can produce the expandable granules according to the first aspect. Thus, the expandable granules and their physical properties (e.g. bulk density and average size) and their components (e.g. lignocellulosic material, one or more expandable particles and / or pre-expanded particles, optionally a binder, optionally a lightweight filler, and optionally a coating) can be the same as described above in the context of the first aspect of the application.

[0085] 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 (preferably the lignocellulosic material already described above in the context of the first aspect) can be provided in any form, e.g. in dry or wet form. According to further preferred embodiments of the second aspect, the expandable particles and / or pre-expanded particles (which can be the expandable particles and / or pre-expanded particles already described above in the context of the first aspect) are provided in dry or wet powder form, or in the form of particles in a slurry, or in the form of a stabilized paint-like formulation or gel.

[0086] 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, as long as the mixing device ensures a uniform mixing of the components. In a further step, the mixed components can be granulated in a step of forming granules, e.g. using any suitable granulator. Typically, the granulator uses a certain pressure, optionally at elevated temperature (compared to room temperature), to form the granules. However, it has to be noted that the pressure used in the granulator cannot be too high, so that the bulk density of the obtained expandable granules does not exceed a potential desired maximum value, e.g. 0.8 g / cm3. 3 Furthermore, if elevated temperature is used for granulation, it also has to be noted that the temperature cannot be too high, so that the one or more expandable particles and / or pre-expanded particles start to expand or even fully expand during the step of forming granules. Thus, any elevated temperature that can be used needs to be adjusted according to the expansion properties (in particular the T 开始 ) of the particular one or more expandable particles and / or pre-expanded particles used. In some embodiments, the granulation is performed using a high-shear mixer. In some embodiments, the granules obtained after granulation are dried, e.g. in a fluidized bed dryer.

[0087] The method according to the second aspect can comprise an additional step of adding a binder, e.g. a binder as described above in the context of the first aspect. The binder can be added to the mixture of already mixed lignocellulosic material and one or more expandable particles and / or pre-expanded particles. However, all three components (including the binder) can also be provided separately and then mixed together.

[0088] The method according to the second aspect can comprise an additional step of adding lightweight particles, e.g. lightweight particles as described above in the context of the first aspect. The lightweight particles can be added to the mixture of already mixed lignocellulosic material and one or more expandable particles and / or pre-expanded particles, optionally also already comprising a binder. However, all three components (including the lightweight particles), or all four components (including the binder and the lightweight particles) can also be provided separately and then mixed together.

[0089] The weight ratio of the lignocellulosic material and the one or more expandable particles and / or pre-expanded particles, and optionally the binder and / or the optional lightweight particles, provided and mixed together is not as such limited. In some embodiments, the weight ratio of the lignocellulosic material and the one or more expandable particles and / or pre-expanded particles is as defined above in the context of the first aspect of the application.

[0090] In some embodiments, the absolute weight range (based on the total weight of the expandable granules) of the lignocellulosic material and the one or more expandable particles and / or pre-expanded particles, and optionally the binder and / or the optional lightweight particles, provided and mixed together is as described above in the context of the first aspect.

[0091] According to a preferred embodiment of the second aspect, the method of manufacturing granules further comprises an additional step d) of adding a coating agent. The coating agent can be any coating agent and can be used in any amount, as already described above in the context of the first aspect of the application. According to a further preferred embodiment of the second aspect, the step d) of adding a coating agent is subdivided into at least two separate and consecutive steps: dl) adding a first coating agent and d2) adding a second coating agent. Of course, further steps can also be performed, e.g. d3) adding a third coating agent, and optionally d4) adding a fourth coating agent. In each of the at least two steps of adding a coating agent, the coating agent added can be the same or different. Each step of adding a coating agent can form a different layer, which can be cured separately or together. The first step dl) of adding a first coating agent forms a first layer directly on the surface of the granules. The second step d2) of adding a second coating agent then forms a second layer on the first layer. The third step d3) of adding a third coating agent then forms a third layer on the second layer, and so on. Preferably, at least three layers are formed on the granules.

[0092] According to a further preferred embodiment of the second aspect, the method of manufacturing granules further comprises an additional step e) drying the granules obtained using the previous steps. Any suitable drying equipment can be used for this step, such as a fluidized bed dryer.

[0093] The present application also provides, according to a third aspect, granules obtainable by the method according to the second aspect.

[0094] The present application also provides, according to a fourth aspect, the use of the granules according to the first or third aspect in the manufacture of a foamed material, such as a shock absorbing material, or an insulation material for a building structure, or an insulating material for insulating or cooling food or food ingredients, such as an environmentally friendly shock absorbing packaging material that can be recycled together with paperboard.

[0095] The present application also provides, according to a fifth aspect, a method for manufacturing a foamed product, preferably comprising less than about 5 wt.% of fossil-based polymers, the method comprising the steps of:

[0096] i) providing one or more granules according to the first aspect, or granules obtained by the method according to the second aspect, or one or more granules according to the third aspect;

[0097] ii) filling the granules into a mould assembly and heating the material, preferably to about 50 to about 150 °C, more preferably to about 55 to about 130 °C, most preferably to about 60 to about 120 °C, thereby providing an expanded foamed product.

[0098] The heating can further be performed, for example, in an oven or in an autoclave, or in a combination thereof.

[0099] According to preferred embodiments of the fifth aspect, heat steam is applied to expand the granules during step ii). According to preferred embodiments of the fifth aspect, the density of the final foamed product is about 0.01 to about 0.5 g / cm3, preferably about 0.025 to about 0.5 g / cm3, such as about 0.05 to about 0.5 g / cm3, or about 0.05 to about 0.3 g / cm3. 3 3 3 3

[0100] According to preferred embodiments, the product obtained in step (ii) can be subjected to a sintering treatment (iii). During such a sintering step, the product obtained in step (ii) is held 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 for example up to 2 hours or up to 1 hour. The sintering step can improve the stability and / or homogeneity of the product.

[0101] ​​​​The present invention also provides according to a sixth aspect a foamed product obtainable by the method according to the fifth aspect.

[0102] When referring to the fourth aspect, i.e. the use of the granulate according to the first or third aspect in the manufacture of a foamed material, e.g. a shock absorbing material, or an insulation material for a building structure, or an insulating material for keeping food or food ingredients warm or cold, the shock absorbing material can be part of a helmet or other safety equipment. When used in the manufacture of an insulating material for keeping food or food ingredients warm or cold, it can be part of a cooling box for keeping fish and / or other seafood (lobster, crayfish, shrimps and the like) fresh. It can also be used in trays for keeping fresh vegetables or fruits. When used as a material for a building structure, it can be part of a building (house, etc.) or furniture.

[0103] Preferred features of each aspect of the present invention apply mutatis mutandis to each of the other aspects. The prior art documents mentioned herein are incorporated herein to the maximum extent legally permissible. The present invention will be further described in the following examples in conjunction with the appended figures, which examples and figures are not intended to limit the scope of the present invention in any way.

[0104] Embodiments of the present invention will be described in greater detail by way of examples of embodiments and with reference to the accompanying drawings, the sole purpose of which is to illustrate the present invention, not to limit its scope in any way.

[0105] Drawings

[0106] Figure 1 of Figure 1 a) and Figure 1 b) show tests regarding the short and long fibers used to prepare the expandable granulate of the present invention. Figure 1 b) shows that the wet fibers from pine needles have a tendency to clump, as these fibers are longer fibers that cause clumping. The length of the fibers is twice the length of birch fibers, which do not have this tendency to clump (see Figure 1 a). Nonetheless, the clumping itself is not detrimental to the expandable granulate of the present invention.

[0107] Figure 1 c) shows expandable granulates of the present invention prepared by using different fiber types in a filling test (the funnel represents a potential form of a very specific mold). The granulates contain 93 wt.% of the respective fiber (birch ( Figure 1 c1)), eucalyptus ( Figure 1 c2)) or pine ( Figure 1 c3)), 5 wt.% of expandable microspheres (available under the trade name Expancel (031 DU40)) and 2 wt.% of starch as a binder. It can be seen that the expandable granulates based on birch and eucalyptus have better filling properties than the expandable granulate derived from pine.

[0108] Figure 1 d) shows expandable granules comprising different types of binders (i.e. starch and different types of carboxymethylcellulose (CMC), i.e. cold water soluble starch, CMC 40 kDa, CMC 100 kDa and CMC 250 kDa).

[0109] Figure 1 e) shows pictures of the expandable granules of the present application before and after different laboratory Pulp Refiner (PFI) grinding treatments, i.e. reference (before treatment), PFI 500 RPM (revolutions per minute) (about 40 kWh / ton) after treatment, PFI 5000 RPM (about 400 kWh / ton) after treatment and PFI 10000 RPM (about 800 kWh / ton) after treatment, respectively.

[0110] Figure 1 f) shows how wet wood fiber pieces (size 2-5 mm, solid content 20-30 wt.%, based on the total weight of the wet wood fiber pieces) are combined with expandable microspheres (obtained under the trade name Expancel 031 WUF 40) (in wet paste form) to obtain granules by optionally adding a binder (“binder”).

[0111] Figure 2 shows a schematic drawing of a preferred embodiment of the expandable granules of the present application (also referred to herein as “Granuler+” Figure 2 a)) and a micrograph thereof Figure 2 b)). In Figure 2 a), a core (1) comprising lignocellulosic fibers (10), expandable microspheres (11) and / or pre-expanded microspheres (12), a lightweight filler (13) and optionally a binder, and a coating (2) comprising expandable microspheres (21) and / or pre-expanded microspheres (22) and a coating (23) are depicted. The coating can for example be a binder, as described above. Figure 2 b) shows a micrograph of such Granuler+.

[0112] Figure 3 shows how the expandable granules of the present application are applied when manufacturing a molded article (e.g. a packaging piece). This is further highlighted in Figure 3 a) (i.e. the step of granulating the expandable granules in a high shear mixer), Figure 3 b) (i.e. the step of drying the granulated expandable granules in a fluidized bed dryer), Figure 3 c) (i.e. the step of filling the expandable granules into a mold before putting the filled mold into an oven at 150°C), and Figure 3 d) (i.e. the molded material after 15 minutes of treatment in the oven).Figure 3 e) shows the product obtained after moulding and sintering after pouring the material (i.e. expandable granules) in a different mould (i.e. cylindrical mould).

[0113] Figure 4 of Figure 4 a) shows the application of the expandable granules of the present application in full size application. Figure 4 b) shows the demoulding of the moulded (and expanded) product from the mould in full size testing.

[0114] Figure 5 shows moulded products made from expandable granules of the present application, wherein the expandable granules comprise respectively recycled fibres Figure 5 a) and waste fibres Figure 5 b and Figure 5 c).

[0115] Example

[0116] Example 1

[0117] Example 1a

[0118] 92.5 wt.% pine fibres (bleached kraft pulp), 5 wt.% expandable microspheres (obtained as Expandex® 031 WUF40 from Nouryon) and 2.5 wt.% CMC (obtained as Finnfix 30F from Nouryon, added as an aqueous solution) were mixed in a kitchen blender with additional water to a total solids content of 25 wt.%.

[0119] The mixture was granulated into granules using a high shear granulator (Diosna P1-6 laboratory mixer, Figure 3 a)), following the method as Figure 1 f) schematically described. The granules were dried to 45% (solids content) in a fluid bed (module MINILAB RC, Diosna, Figure 3 b)) and the granules were analysed by visual inspection, microscopic inspection and flowability fill test.

[0120] It was concluded that the long fibres from pine produced “hairy”, non-spherical granules. Such non-spherical granules can be less suitable for specific complex mould shapes as shown in Figure 3 c). However, such non-spherical granules are still suitable for less complex mould shapes, such as bricks or cylinders. Figure 1 b) and Figure 1 c3) shows the granules made in the present example.

[0121] Example 1b

[0122] 92.5 wt.% birch fiber (bleached sulfate pulp), 5 wt.% expandable microspheres (obtained from Nouryon as 031WUF40), and 2.5 wt.% CMC (obtained from Nouryon as Finnfix 30F, added as an aqueous solution) were mixed with additional water in a kitchen mixer to a total solids content of 25 wt.%. The mixture was then granulated using a high-shear granulator (Diosna, P1-6 laboratory mixer). Figure 3 a)), according to as follows Figure 1 f) The method illustrated herein is used to prepare the mixture into granules. In a fluidized bed (module MINILAB RC, Diosna), Figure 3 In step b), the granules are dried to 45% (solid content) and analyzed by visual inspection, microscopic inspection and flowability test.

[0123] The conclusion is that short fibers from birch can be used to create spherical pellets with a fairly smooth surface, which can be filled into specific complex mold shapes for the production of molded EPS products. Figure 1 a) and Figure 1 c3) shows the granules produced in this embodiment.

[0124] These granules are filled into a mold. Figure 3 c)) Then heat it to about 150°C for 15 minutes. Figure 3 d) also shows the resulting fused (or molded) material.

[0125] Example 1c

[0126] 92.5 wt.% eucalyptus fiber (bleached sulfate pulp), 5 wt.% expandable microspheres (obtained from Nouryon as 031WUF40), and 2.5 wt.% CMC (obtained from Nouryon as Finnfix 30F, added as an aqueous solution) were mixed with additional water in a kitchen mixer to a total solids content of 25 wt.%. The mixture was then granulated using a high-shear granulator (Diosna P1-6 laboratory mixer). Figure 3 a)), according to Figure 1 f) The method illustrated herein is used to prepare the mixture into granules. In a fluidized bed (module MINILAB RC, Diosna), Figure 3 In step b), the granules are dried to 45% (solid content) and analyzed by visual inspection, microscopic inspection and flowability test.

[0127] The conclusion is that short fibers from eucalyptus can be used to create spherical pellets with a fairly smooth surface, which can be filled into specific complex mold shapes for the production of molded EPS products. Figure 1c2) shows the pellets made in this example.

[0128] Example 1 d

[0129] 94 wt.% birch fibres (bleached kraft pulp), 5 wt.% expandable microspheres (obtained as 031 WUF 40 from Nouryon) and 1 wt.% cold water soluble starch (obtained as Solbond PC 65L from SOLAM; added as an aqueous solution) were mixed in a kitchen blender with additional water to a total solids content of 25 wt.%. A high shear pelletizer (Diosna, type C 300) was used to make the mixture into pellets. The pellets were dried in a fluid bed (Diosna, type C 300) to 45% (solids content) and analyzed by visual inspection, microscopic inspection and flowability fill test. Figure 3 a)) according to the method as Figure 1 f) described. The mixture was made into pellets. The pellets were dried in a fluid bed (Diosna, Figure 3 b)) to 45% (solids content) and analyzed by visual inspection, microscopic inspection and flowability fill test.

[0130] It was concluded that the starch also acts as a binder in this system, making it possible to make spherical pellets with birch fibres (bleached kraft pulp) with a rather smooth surface, which can also be filled into specific complex mould shapes for the production of moulded EPS articles.

[0131] Example 1 e

[0132] 94 wt.% recycled paper pulp (i.e. recycled fibres), 5 wt.% expandable microspheres (obtained as 031 WUF 40 from Nouryon) and 1 wt.% cold water soluble starch (obtained as Solbond PC 65L from SOLAM, type; added as an aqueous solution) were mixed in a kitchen blender with additional water to a total solids content of 25 wt.%. A high shear pelletizer (Diosna, type C 300) was used to make the mixture into pellets. The pellets were dried in a fluid bed (Diosna, Figure 3 a)) according to the method as Figure 1 f) described. The mixture was made into pellets. The pellets were dried in a fluid bed (Diosna, Figure 3 b)) to 45% (solids content) and analyzed by visual inspection, microscopic inspection and flowability fill test.

[0133] It was concluded that the recycled paper pulp made it possible to make spherical pellets with a rather smooth surface, which can be filled into specific complex mould shapes for the production of moulded EPS articles. Figure 5 a) shows a moulded article made from recycled paper pulp pellets.

[0134] Example 1 f

[0135] A waste paper pulp (i.e. waste fibres) of 94 wt.%, expandable microspheres (obtained as Expandex® 031 WUF40 from Nouryon) of 5 wt.% and cold water soluble starch (obtained as Solbond PC 65L from SOLAM; added as an aqueous solution) of 1 wt.% were mixed in a kitchen blender with additional water to a total solids content of 25 wt.%.

[0136] A high shear granulator (Diosna, Granulator 25 / 50) was used to produce the granules. Figure 3 a)) according to the method described in Example 1 b) and 1 d) above. Figure 1 f) The mixture was granulated according to the method described schematically in Figure 1. The granules were dried to 45% (solids content) in a fluid bed (Diosna, Fluid Bed Dryer 25 / 50) and analysed by visual inspection, microscopic examination and flowability fill tests. Figure 3 b)) according to the method described in Example 1 b) and 1 d) above.

[0137] It was concluded that waste paper pulp produced spherical granules with smooth surfaces that could be filled into specific complex mould shapes for the production of moulded EPS articles. Figure 5 b) and Figure 5 c) shows a moulded article made from waste paper pulp granules.

[0138] Example 2

[0139] Various CMCs (obtained as Finnfix products from Nouryon, types 30F, 40F and 100F) of different forms and different molecular weights (40 kDa, 100 kDa and 250 kDa) were investigated as potential binders and compared to cold water soluble starch as a binder. The final granules produced according to the method described in Example 1 b) and 1 d) above presented different shapes as shown in Figure 1 d). The results showed that the type of binder and its molecular weight influenced the final morphology of the granules. The 100 kDa CMC (Finnfix 30F) had the best binding properties.

[0140] Example 3

[0141] Experiments were carried out to grind birch fibres to different levels. The granules produced from birch fibres of different grinding levels are shown in Figure 1 e. Even short birch fibres showed some tendency to produce "hairy" granules. By grinding the fibres in the wet state (Escher Wyss lab grinder), the length and surface of the fibres could be changed, which in turn influenced the morphology of the granules. Grinding the birch fibres at 5000 rpm seemed to work best to produce granules with a spherical and smooth surface, which performed well in the fill tests.

[0142] Example 4

[0143] The pellets of example 1 c were sprayed in the pelletizing tool with a 2.5 wt.% solution of CMC in water forming a thin layer, without using a high speed chopper. Subsequently expandable microspheres (obtained as Expancel 031 WUF40 from Nouryon) were added while the pellets were in motion. An excess of microspheres was added to create a visual effect. The expandable microspheres were adsorbed on the surface of the pellets by wetting the sticky CMC, resulting in a core-shell pellet product with a surface coating of expandable microspheres. Figure 2 a) illustrates the core-shell principle schematically, Figure 2 b) shows an SEM image of a cross section of such a core-shell pellet.

[0144] Example 5

[0145] A larger scale molding was tested using the formulation of the combination of examples 1 b, 2 and 3, with equipment commonly used for manufacturing molded EPS. Full scale trials on an EPS molding machine showed that the pellets filled the mold and fused together very well by the steam used to heat the material in the mold (see figures 4a and 4b). Figure 4 a) and 4b)).

[0146] · It can be demonstrated that:

[0147] · The material, i.e. the expandable pellets of the invention, behaves in a similar way as when manufacturing EPS.

[0148] · The material can be filled into molds of different shapes.

[0149] · The pellets expand and fuse into a molded article.

[0150] · The molded article can be demolded from the mold.

[0151] It can also involve one or more demolding agents to enable the fused material to be relatively easily demolded from the tool (which can stick to the tool, i.e. the mold). The tool is filled with the expandable pellets of the invention (about 30-35 liters), which are subsequently heated with hot steam, causing the pellets to expand and fuse together in the mold, forming a shaped article. Thus, according to the fourth aspect of the invention, the aforementioned steps, a foamed product is manufactured from the expandable pellets in a mold used for producing molded EPS.

[0152] Various embodiments of the application have been described above, but those skilled in the art will recognize that further modifications can be made thereto without departing from the scope of the application. The breadth and scope of the present application 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 above-described pellets / compositions or methods can be combined with other known methods. Other aspects, advantages and modifications within the scope of the application will be apparent to those skilled in the art.

Claims

1. Expandable pellets comprising lignocellulosic material and one or more expandable and / or pre-expanded particles, and optionally lightweight particles, optionally further comprising one or more binders, wherein the bulk density of the expandable pellets is from about 0.05 to about 0.8 g / cm3 3 , preferably from about 0.1 to about 0.8 g / cm3 3 .

2. Expandable pellets according to claim 1, wherein the expandable pellets comprise less than 12 wt.%, preferably less than 10 wt.% and more preferably less than 5 wt.% of the one or more expandable particles and / or pre-expanded particles.

3. Expandable pellets according to claim 1 or 2, wherein the expandable pellets comprise 50 wt.% or more, preferably 70 wt.% or more, more preferably 80 wt.% or more and most preferably 90 wt.% or more of the lignocellulosic material.

4. Expandable pellets 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. Method of manufacturing expandable pellets 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 the lignocellulosic material with the particles, preferably comprising the additional step of adding a binder.

6. Method of manufacturing expandable pellets 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. Method of manufacturing expandable pellets according to claim 5 or 6, wherein the expandable particles are provided in the form of dry or wet powders, or in the form of particles in a slurry or in the form of a gel.

8. Method of manufacturing expandable pellets according to any one of claims 5 to 7, wherein the expandable particles are heat-expandable thermoplastic microspheres or heat- pre-expanded microspheres, or a combination thereof.

9. Method of manufacturing pellets 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 fibers, preferably selected from the group consisting of starch, chitosan, carboxymethyl cellulose and any combination thereof, most preferably starch, wherein it is particularly preferred that the polymer is added in an amount of at most about 2 wt.%.

10. Method of manufacturing pellets according to any one of claims 5 to 7, further comprising the additional step c) adding a coating agent; and / or further comprising the additional step d) drying the pellets obtained using the preceding steps.

11. Method of manufacturing pellets 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 pellets.

12. The method of manufacturing pellets according to any one of claims 5 to 11, wherein the bulk density of the expandable pellets is from about 0.05 to about 0.8 g / cm 3 , preferably from about 0.1 to about 0.8 g / cm 3 .

13. Method of manufacturing pellets according to any one of claims 5 to 12, wherein the pellets are made into a substantially spherical shape.

14. Method of manufacturing pellets according to any one of claims 5 to 13, wherein the cellulose fibers are derived from softwood or hardwood or a combination thereof, preferably hardwood, such as birch or eucalyptus or a combination thereof, most preferably obtained by chemical methods.

15. Method of manufacturing pellets according to any one of the preceding claims 5 to 14, wherein the pellets comprise less than 5 wt.% of one or more fossil-based polymers.

16. A pellet obtainable by the method of any one of claims 5 to 15.

17. Use of the pellet of claim 1 or 16 in the manufacture of a foamed material, such as a shock absorbing material, or an insulating material for a building structure, or an insulating material for insulating or cooling food or food ingredients, for example in the manufacture of an environmentally friendly shock absorbing packaging material that can be recycled with paperboard.

18. A method of manufacturing a foamed product, preferably comprising less than about 5 wt.% of fossil-based polymers, the method comprising the steps of: i) providing one or more pellets of any one of claims 1 to 4, or pellets obtained by the method of any one of claims 5 to 15, or one or more pellets of claim 16; and ii) filling the pellets into a mould assembly and heating the material, preferably to about 50-150 °C, more preferably to about 55-130 °C, most preferably to about 60-120 °C, thereby providing an expanded foamed product.

19. The method of claim 18, wherein steam is applied to expand the pellets during step ii).

20. The method according to claim 18 or 19, wherein the density of the final foamed product is from about 0.025 to about 0.5 g / cm³. 3 Preferably, it is about 0.025 to about 0.3 g / cm³. 3 .

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

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