A material useful for a package and a method for making such material

Abstract

The present invention relates to a method for making granule suitable for use in a package or similar, and use of said granule e.g. in package applications.

Description

[0001] A material useful for a package and a method for making such material

[0002] Field of the invention

[0003] The present invention relates to a method for making a granule, suitable for making a package or similar, and usage thereof and its end product.

[0004] Background

[0005] The application and manufacture of expanded PS (expanded polystyrene, EPS) or PP (expanded polypropylene, EPP) for use in packages and in various construction applications have previously been described. However, these foamed and / or molded products are still based upon raw material emanating from fossil resources, e.g. oil. The production of EPS yearly embraces millions of tonnes worldwide, and only a fraction of said products are recycled and some even estimate that some landfills may comprise from 25 - 35 wt % of EPS.

[0006] Through EP0752444-A1 there is described a moldable pulp material useful for the production of environmentally friendly shock absorbing packaging for electric appliances as a substitute for polystyrene foam packaging. In the method, 1 to 5 weight % thermally expandable hollow particles are mixed with a pulp, comprised of strips of paper, and a starch binder in water.

[0007] The mixture is filled into a mold assembly and compressed under heat to produce a molded pulp product.

[0008] Through WO0154988-A2 there is described a low-density paperboard article useful as insulated container instead of using EPS. The method includes providing a papermaking furnish containing cellulosic fibers, and from about 0.25 to about 10 % by weight dry basis expandable microspheres, preferably from about 5 to about 7 wt. %, forming a paperboard web from the papermaking furnish on a papermaking machine. The density is mentioned to be 6.0 to about 10 lb / 3MSF / mil.

[0009] Through US2018072860A1 there is disclosed thermoplastic expandable microspheres glued onto cellulose fibers. These are not granules, not at all free-flowing light-weight granules of cellulose fibers and expandable microspheres. Thus, these will not fill a mold.

[0010] Through DE3444264A1 it is described dewatering of a slurry of lignocellulosic material and expandable microspheres by filtering or pressing and expanding the microspheres by providing heat. However, said method does not provide for a method that may make flexible foamed and molded products at virtually any shape. There is thus a need for material useful in packages that are minimizing the usage of fossil resources for their raw material, at the same time also providing an easy to handle material, and at the same time providing a reasonable density such as a density from about 0.05 to about 0.8 g / cm3. There is a strong benefit also if the new material can be recycled in the established recycle streams (curb side) for paper and board. In addition, said new material may also be used drop-in in existing equipment for producing EPS.

[0011] Summary of the invention

[0012] The present invention solves / alleviates one or more of the above problems by providing according to a first aspect a method for manufacturing lightweight granules, which may be used for flexible, molded foamed packaging materials, from >95% lignocellulose base, comprising the following steps: a) providing lignocellulosic material, preferably cellulosic fibers, in a pumpable aqueous suspension and b) optionally, adding a debonding agent, and / or a plasticizer, and optionally; which is preferred, applying a high shear defibrillation step (grinding) to increase the surface area in the system, and c) providing one or more expandable particles and / or pre-expanded particles and optionally light weight particles, and mixing said lignocellulosic material with said particles, and d) adding a binding agent and / or a polymeric flocculation agent, and e) dewatering the mix, thus providing a homogeneous matrix, preferably to a solid content of from about 20 to about 40%, most preferred using centrifugation and / or a press filter, and f) granulating, thus providing granules, preferably whereby charging the wet fiber-based material mix into a high shear granulator to make granules or conveying said material onto a fluid bed to make granules, optionally followed by drying said granules.

[0013] According to a second aspect of the present invention there is provided a granule obtainable by a method according to the first aspect.

[0014] According to a third aspect of the present invention there is provided use of the granule according to the second aspect in flexible, in molded foamed packaging materials, a container or a package, wherein said container may be a disposable drinking cup or dairy product carton or auto-clave package or a tray, or a plate for eating or keeping food, or a box for keeping fruit or fish or shell fish, or in the manufacturing of a chock absorbing material, or an insulation material for building constructions or an isolation material for keeping warm or cold food or food ingredients, or in an environmentally friendly shock absorbing packaging material which may be recyclable with paper board.

[0015] Also provided according to a fourth aspect of the present invention is a method for manufacturing of a foamed product, preferably comprising less than about 5 % of a fossilbased polymer or plastic material, comprising the following steps: i) providing one or more granules obtained by a process according to the first aspect, or one or more granules according to the second aspect, ii) filling said granules into a mold assembly and heating said material from about 50 to about 150° C, preferably from about 50 to about 120° C, most preferred from about 60 to about 100° C, thus providing a dry content of from about 60 to about 90% and thus providing an expanded foamed product, especially preferred wherein steam is applied during step ii) for expanding said granules.

[0016] Thus, steam is a preferred means for expansion (and thus providing an expanded foamed product) during step ii) of the fourth aspect.

[0017] Also provided according to a fifth aspect of the present invention is a foamed product obtainable by a method according to the fourth aspect. In said fourth aspect a preferable way of transferring heat, and thus heating said material, is to use hot steam.

[0018] The method according to the first aspect of the present invention also prevents dusting issues upon drying and loss of material in subsequent treatment steps (which could be drying, packing or charging). Also, difficulties with filling the granules with enough light-weight fillers to reach low granule densities (<150 g / L) may also be alleviated.

[0019] Detailed description of the invention

[0020] It is intended throughout the present description that the expressions “expandable particles” and / or “pre-expanded particles” embraces any expandable particle useful in the context of the present invention. Such particles may be any particle which is expandable, i.e. which increases its volume for instance when being heated. Such particles may e.g. be expandable microspheres. Examples of such expandable microspheres are microspheres marketed under the name Expancel ® Microspheres by Nouryon. These particles may also be preexpanded particles, i.e. expandable particles, which have already been partially but not yet fully expanded, and which upon exposure to heat, e.g. by means of hot gases, such as steam, will expand further. 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 its pressure and hence expands the polymeric shell resulting in an expanded particle. Expandable particles and / or pre-expanded particles are discrete particles, i.e. single particles which are separated from each other, with one single hollow core which is enclosed by the polymeric shell.

[0021] 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 invention, such as those marketed under the trademark Expancel® as said above. The expandable thermoplastic microspheres can be of fossil based or bio-based polymer material. Useful expandable microspheres are described in the literature, for example in U.S. Pat. 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 US Patent Applications 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 JP Laid Open No. 1987-286534 and 2005-272633. Suitable expandable thermoplastic microspheres typically have a thermoplastic shell made from polymers or copolymers obtainable by polymerizing various ethylenically unsaturated monomers, which can be nitrile containing monomers, such as acrylonitrile, methacrylonitrile, alpha chloroacrylonitrile, alphaethoxyacrylonitrile, fumaronitrile or crotonitrile; acrylic esters such as methylacrylate 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 styrenes or alphamethyl styrene; dienes such as butadiene, isoprene and chloroprene; or other kinds of monomers such as vinyl pyridine. Suitable monomers might also be those which have been obtained from renewable sources and, hence, are bio-based, such as for instance lactone based monomers (e.g. in WO 2019 / 043235 A1), itaconate dialkylester monomers (e.g. in WO 2019 / 101749 A1), or tetrahydrofurfuryl (meth)acrylate monomers (e.g. in WO 2021 / 198487 A1 and WO2021 / 198492 A1). Any mixtures of the abovementioned monomers may also be used. In some embodiments, it is preferable that the expandable particles and / or pre-expanded particles comprise monomers from renewable sources. It may sometimes be desirable that the monomers for the polymer shell also comprise crosslinking multifunctional monomers, such as one or more of 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, pentaerythritol hexa(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, triallylformal tri(meth)acrylate, allyl methacrylate, trimethylol propane tri(meth)acrylate, trimethylol propane 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 from 0.1 to 1 wt.%, most preferably from 0.2 to 0.5 wt.% of the total amounts of monomers for the polymer shell. Preferably, the polymer shell constitutes from 60 to 95 wt.%, most preferably from 70 to 85 wt.%, of the total microsphere. The softening temperature of the polymer shell, normally corresponding to its glass transition temperature (Tg), is preferably within the range of from 50 to 250° C., or from 70 to 230° C. The foaming agent encapsulated by the polymer shell in a microsphere is normally a liquid having a boiling temperature not higher than the softening temperature of the thermoplastic polymer shell. The foaming agent, also referred to as blowing agent or propellant, may 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. Also, other hydrocarbon types may be used, such as petroleum ether, and chlorinated or fluorinated hydrocarbons, such as methyl chloride, methylene chloride, dichloro ethane, dichloroethylene, trichloroethane, trichloroethylene, trichlorofluoromethane, etc. Particularly preferred foaming agents comprise at least one of isobutane, isopentane, isohexane, cyclohexane, isooctane, isododecane, and mixtures thereof. The foaming agent suitably makes up from 5 to 40 wt.% of the total weight of the microsphere. The boiling point of the foaming agent at atmospheric pressure may be within a wide range, preferably from - 20 to 200° C., most preferably from -20 to 150° C., and most preferably -20 to 100° C. The thermally expandable thermoplastic microspheres are heated to effect expansion thereof. The temperature at which the expansion of the microspheres starts is called TStart while the temperature at which maximum expansion is reached is called Tmax , both determined at a temperature increase rate of 20° C. per minute. The thermally expandable microspheres used in the present invention suitably have a TStart of from 50 to 200° C., preferably from 70 to 180° C., most preferably from 70 to 150° C. The thermally expandable microspheres used in the present invention suitably have a Tmax of from 70 to 300° C., preferably from 80 to 250° C., most preferred from 100 to 200° C. The expandable microspheres preferably have a volume median diameter of 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 Master sizer Hydro 2000 SM apparatus on wet samples. By heating to a temperature above Tmax, it is normally possible to expand the microspheres from 2 to 5 times their original diameter or more, preferably from 3 to 5 times their original diameter. Preexpanded particles can be prepared from any of the above-described expandable particles.

[0022] The expressions “mold” or “mould” may be used interchangeably in the present specification and would have the same meaning. This also pertains the expressions “fiber” or fibre” mutatis mutandis.

[0023] When it comes to debonders, they may affect (interfere with) hydrogen bonding within a system of cellulose fibers (biopolymer system) and can also affect surface tension and capillary suction upon drying such system. Together these effects may help make a lower density material with higher flexibility and resiliency after drying. Non-limiting examples of debonders are cationic surfactants, nonionic surfactants and amphiphilic surfactants. Quaternary ammonium compounds having one or two fatty alkyl chains may traditionally be used for the making of soft tissue products, but non-toxic, biobased and biodegradable surfactants may be preferred for environmental reasons. The hydrophobic tail may also have a steric effect and therefore act as a lubricant between fibers, for enhanced flexibility.

[0024] When it comes to plasticizers for cellulose fiber systems (biopolymer systems) they may affect / interfere with hydrogen bonding within the system and make material with higher flexibility and resiliency after drying. Plasticizers effective for these systems may typically be low molecular weight molecules with hydrogen bonding capabilities, preferably non-toxic and biobased. Non-limiting examples of plasticizers are glycerol and sorbitol.

[0025] The expandable granule comprises 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 and is also called lignocellulosic biomass. Lignocellulosic material is normally composed of two kinds of carbohydrate polymers, cellulose and hemicellulose, and an aromatic-rich polymer called lignin. Preferably, the lignocellulosic material is cellulosic fibers. The lignocellulosic material may be virgin material or already recycled material, such as recycled fibers, or rejected material, such as rejected fibers, (i.e. material which is virgin material, but which has not passed certain quality control steps for other applications), or a combination thereof. It may be preferred that the lignocellulosic material comprises at least some recycled or rejected material, and preferably mainly (such as more than 50 wt.%, more than 70 wt.%, more than 80 wt.-% or more than 90 wt.%) comprises recycled or rejected material. It may also be so that, the lignocellulosic material essentially consists of recycled or rejected material, which also may be preferred. According to a preferred embodiment of the first aspect, said cellulosic fibers may emanate from softwood or hardwood or a combination thereof, preferably hardwood, such as birch or eucalyptus, or a combination thereof, most preferred obtained through a chemical process. Said cellulosic fibers may emanate from ground wood (grinding pulp), chemi-thermo- mechanical pulp (CTMP), such as BCTMP, i.e. bleached CTMP, thermomechanical pulp (TMP), sulphate pulp, such as Kraft pulp, sulfite pulp, non-wood pulp, recycled pulp material (recycled fibers), rejected pulp material, pulp for paper and board and / or for carton or combinations thereof. Most preferred said cellulosic fibers are obtained through a chemical process as when manufacturing e.g. CTMP or BCTMP. The cellulosic fibers may emanate from bleached or non-bleached pulp, or a combination thereof. The cellulosic fibers may emanate from hardwood (such as eucalyptus, beech, oak, birch) or softwood (such as pine or spruce), or a combination thereof. Straw, reed, bamboo and bagasse or a combination thereof are also feasible raw material also in said context. Preferred source is as said, hardwood; especially preferred birch or eucalyptus, or a combination thereof.

[0026] According to a preferred embodiment of the first aspect, said lignocellulosic material emanates from chemical thermomechanical pulp (CTMP), thermomechanical pulp (TMP), sulfate pulp, such as Kraft pulp, sulfite pulp, non-wood pulp, recycled pulp material (recycled fibers), rejected pulp material, pulp for paper and board and / or for carton, or a combination thereof.

[0027] According to a preferred embodiment of the first aspect, said lignocellulosic material emanates from bleached or non-bleached pulp, or a combination thereof

[0028] According to a preferred embodiment of the first aspect, said lignocellulosic material emanates from hardwood (such as eucalyptus, beech, oak, birch) or softwood (such as pine or spruce), bagasse, reed, bamboo, algae or straw or a combination thereof. When it comes to hardwood, as said, eucalyptus, birch or a combination thereof is especially preferred.

[0029] According to a preferred embodiment of the first aspect, said drying of step f) is performed to achieve from about 70 to about 100% dryness through using one or more of the following processes: through fluid bed drying using hot air, or using InfraRed radiation (IR) or using hot air without using fluid bed, preferably wherein the drying temperature is below 100 °C.

[0030] Said granule of the second aspect may comprise less than 5 wt % of one or more fossil based polymers and less than 5 wt% of plastic materials. According to a preferred embodiment of the fourth aspect the density of said finalized foamed product is from about 0.025 to about 0.5 g / cm3, preferably from about 0.05 to about 0.5 g / cm3.

[0031] The granule according to a second aspect of the present invention obtainable by a method according to the first aspect may be an expandable granule comprising lignocellulosic material and one or more expandable particles, pre-expanded particles or other light weight particles, optionally also containing one or more binding agents, having a bulk density from about 0.05 to about 0.8 g / cm3preferably about 0.1 to about 0.8 g / cm3, preferably wherein the expandable particles are present in an amount of below 5 wt%. Said expandable granule comprises biopolymeric materials (incl. lignocellulosic material) of at least 95 wt%.

[0032] By proper mixing of the components (in water) before charging to the granulator as set above for the method according to the first aspect of the present invention, particles and chemical additives may be well distributed and embedded in the fiber matrix. This way, (fine) particles are more efficiently retained in the fiber matrix and dusting and loss of material is minimized. Said method also allows for higher additions of expandable microspheres and light-weight fillers, which in turn allows for the making of granules and foamed materials of lower density and higher flexibility (spongy properties).

[0033] With no debonding agent, surface tension of water pulls cellulose fibers close to each other by capillary forces when the water volume decreases upon evaporation (drying). This results in rather dense granules with many fiber-fiber contacts (hydrogen bonds). This dense product (granule) may be challenging to transfer to a mold and challenging also to make to expand in a mold. Hydrogen bonds counteract expansion of the fiber network, even in the presence of steam (water molecules) that usually compete for the fiber-fiber and fiber- polymer hydrogen bonds. The addition of a debonding agent may modify surface tension of the water-based system so that the cellulose network remains relatively loosely connected upon drying. Low-density granules may thus be formed which are easily transferred to the mold and expands nicely in the mold. The use of a plasticizer may also help reduce the effect of hydrogen bonds, leading to a foamed material that is more elastic, more flexible and formable. The method according to the first aspect of the present invention provides means to make lightweight granules which in turn enables making low-density flexible, molded foamed packaging materials from >95% lignocellulose base (as set out for the fourth and fifth aspect of the present invention). In addition, as EPS beads need to be stored in a prefoamed condition during a certain time, e.g. up to 4 months, before final forming, in order to release pentane and reach target density, this delay (and storage time) may be avoided when using granules made according the first aspect of the present invention or granules of the second aspect of the present invention when making e.g. package material. The usage of one or more additional storage silos may also be avoided as there will be no need for storing pre-foamed EPS.

[0034] The expandable granule may further comprise light weight particles. The light weight particles are not limited and in principle any light weight particles commonly known by the skilled person can be comprised in the expandable granule of the present invention. In some embodiment, the light weight particles are lightweight fillers, such as fumed silica, aerogels, fly ash and other porous ceramics, porous aluminium hydroxides or aluminium silicates, porous polymer beads, already expanded microspheres, such as expanded thermoplastic microspheres, or a combination thereof.

[0035] A light weight particle has for instance a density of below 0.5 g / cm3, preferably below 0.3 g / cm3, and more preferably below 0.15 g / cm3. A light weight particle may have a minimum density of 0.001 g / cm3, such as a minimum density of 0.005 g / cm3 or a minimum density of 0.01 g / cm3. The amount of the light weight particles as such in the expandable granule is not limited. However, in some preferred embodiments, the amount of the light weight particles in the expandable granule is up to 10 wt.%, such as up to 8 wt.%, or up to 7 wt.%, and preferably up to 5 wt.%, such as up to 3 wt.%, the wt.% being based on the total weight of the expandable granule. In some preferred embodiments, the amount of the light weight particles in the expandable granule 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 granule. Hence, in some embodiments, the amount of the light weight particles in the expandable granule is from, 0.1 to 10 wt.%, such as from 0.2 to 8 wt.%, preferably from 0.5 to 5 wt.%, and most preferably from 1 to 3 wt.%, the wt.% being based on the total weight of the expandable granule. The light weight particles may help to reduce the average bulk density of the expandable granule and can be used to adjust the average bulk density of the expandable granule to a certain desired average bulk density.

[0036] One of more benefits with the present invention is that the granules set out above may be used in existing molding equipment for production of molded EPS, using e.g. steam as the heating media.

[0037] When it comes to said third aspect viz. use of a granule according to the second aspect, it may be used in molded foamed packaging materials, a container or a package, wherein said container may be a disposable drinking cup or dairy product carton or auto-clave package or a tray, or a plate for eating or keeping food, or in a box for keeping fruit or fish or shell fish, or in the manufacturing of a chock absorbing material, or in an insulation material for building constructions or an isolation material for keeping warm or cold food or food ingredients, or in an environmentally friendly shock absorbing packaging material which may be recyclable with paper board, wherein said use of said granule may also be in the manufacturing of a foamed material, such as a chock absorbing material, or in an insulation material for building constructions or in an isolation material for keeping warm or cold food or food ingredients, the chock absorbing material may be a part of a helmet or other safety equipment. When it comes the usage in the manufacture of an isolation material for keeping warm or cold food or food ingredients, it may be part of a cooling box for keeping fish and / or other see food (lobsters, cray fish, shrimps and similar) fresh. It may also be used in trays for keeping fresh vegetables or fruit. When used as a material for building constructions this maybe part of a building (house and such) or a furniture.

[0038] Preferred features of each aspect of the invention are as for each of the other aspects mutatis mutandis. The prior art document (s) mentioned herein are incorporated to the fullest extent permitted by law. The invention is further described in the following example, which do not limit the scope of the invention in any way.

[0039] Embodiments of the present invention are described as mentioned in more detail with the aid of examples of embodiments, the only purpose of which is to illustrate the invention and are in no way intended to limit its extent.

[0040] Example

[0041] The granules should, according to the present invention, comprise of more than 95 wt% of lignocellulosic materials and less than 5 wt% of one or more fossil based polymers and less than 5 wt% of plastic materials. However, to efficiently evaluate the solution to the identified dusting problems, the recipe used in the examples below was modified to contain higher amounts of expandable microspheres and pre-expanded microspheres. Previous trials have helped identify the expandable microspheres, pre-expanded microspheres and any other light weight filler to be the main contributors to the dust. By adding more than 5 wt% of expandable and pre-expanded microspheres and thereby add less than 95 wt% material of lignocellulosic base in the making of the granules, it was easier to evaluate the effect of the present invention on reducing the formation of dust in sub-sequent processing steps. Dusting is a major problem when the components are dry-mixed before charging to the granulator or dry-mixed in the granulator. This becomes obvious upon sub-sequent drying of the granules in a fluid-bed dryer. It was concluded that a large volume fraction of the dust was low-density pre-expanded microspheres that escaped the granules.

[0042] The composition of the granules in the reference trial was: 150 parts cellulose pulp, 22 parts CMC, 4 parts expandable microspheres, 6 parts pre-expanded microspheres. Dry cellulose fibers (bleached birch) were mixed with the microspheres before CMC solution (4% in water) was sprayed onto the dry mix in the granulator. After granulating at 25% solids, the granules were transferred to a fluid-bed dryer and dried to 80% solid content. Severe dusting was observed and the air filters cleaning the exhaust air were covered in fine dust after drying one 190 g batch.

[0043] By proper mixing of the components in a concentrated water-based slurry before charging to the granulator, light weight pre-expanded microspheres, expandable microspheres and chemical additives could be well distributed and embedded in the fiber matrix. This way, fine particles could be more efficiently retained in the fiber matrix and dusting and loss of material is minimized.

[0044] The composition of the granules in this comparing trial was the same as in the reference above: 150 parts cellulose pulp, 22 parts CMC, 4 parts expandable microspheres, 6 parts pre-expanded microspheres. Dry cellulose fibers (bleached birch) were mixed with water in a tank with stirrer, and adding the microspheres and CMC solution (4% in water) while mixing. When the components were well mixed after a few minutes, the slurry was transferred to a centrifuge and excess water was removed. The wet cake (25% solids) was charged to the granulator for granulation. The granules were then transferred to a fluid-bed dryer and dried to 80% solid content. Now dusting was reduced to a minimum and the air filters cleaning the exhaust air stayed substantially free from fine dust after drying one 190 g batch.

[0045] Various embodiments of the present invention have been described above but a person skilled in the art realizes further minor alterations that would fall into 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 above-noted granules / compositions or methods may be combined with other known methods. Other aspects, advantages- and modifications within the scope of the invention will be apparent to those skilled in the art to which the invention pertains.

Claims

Claims1 . A method for manufacturing lightweight granules, which may be used for flexible, molded foamed packaging materials, from >95% lignocellulose base, comprising the following steps: a) providing lignocellulosic material, preferably cellulosic fibers, in a pumpable aqueous suspension and b) optionally, adding a debonding agent, and / or a plasticizer, and optionally, which is preferred, applying a high shear defibrillation step to increase the surface area in the system, and c) providing one or more expandable particles and / or pre-expanded particles and optionally light weight particles, and mixing said lignocellulosic material with said particles, d) adding a binding agent and / or a polymeric flocculation agent, and e) dewatering the mix, thus providing a homogeneous matrix, preferably to a solid content of from about 20 to about 40%, most preferred using centrifugation and / or a press filter, and f) granulating thus providing granules, preferably whereby charging the wet fiber-based material mix into a high shear granulator to make granules or conveying said material onto a fluid bed to make granules, optionally followed by drying said granules.

2. A method according to claim 1 wherein the lignocellulosic material emanates from chemical thermomechanical pulp, thermomechanical pulp, sulfate pulp, such as Kraft pulp, sulfite pulp, recycled pulp material, rejected pulp material, board or carton, or a combination thereof.

3. A method according to claim 1 wherein the lignocellulosic material emanates from bleached or non-bleached pulp, or a combination thereof.

4. A method according to claim 1 wherein the lignocellulosic material emanates from hardwood or softwood, bagasse, algae or straw or a combination thereof.

5. A method according to claim 1 wherein said drying of step f) is performed to achieve from about 70 to about 100% dryness through using one or more of the following processes: through fluid bed drying using hot air, or using InfraRed radiation, or using hot air without using fluid bed, preferably wherein the drying temperature is below about 100 °C.

6. A granule obtainable by a method according to any one of claims 1 - 5.

7. Use of a granule according to claim 6 in flexible, molded foamed packaging materials, a container or a package, wherein said container may be a disposable drinking cup or dairy product carton or auto-clave package or a tray, or a plate for eating or keeping food, or a box for keeping fruit or fish or shell fish, or in the manufacturing of a chock absorbing material, or an insulation material for building constructions or an isolation material for keeping warm or cold food or food ingredients, or in an environmentally friendly shock absorbing packaging material, preferably recyclable with paper board.

8. A method for manufacturing of a foamed product, preferably comprising less than about 5 % of a fossil-based polymer or plastic material, comprising the following steps: i) providing one or more granules obtained by a process according to any one of claims 1 - 5, or one or more granules according to claim 6, ii) filling said granules into a mold assembly and heating said material from about 50 to about 150° C, preferably from about 50 to about 120° C, most preferred from about 60 to about 100° C, thus providing a dry content of from about 60 to about 90% and thus providing an expanded foamed product, especially preferred wherein steam is applied during step ii) for expanding said granules.

9. A method according to claim 8 wherein the density of said finalized foamed product is from about 0.025 to about 0.5 g / cm3, preferably from about 0.05 to about 0.5 g / cm3.

10. A foamed molded product obtainable by a method according to any one of the claims 8 - 9.