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SE2050888A1 - 3D shaped packaging product - Google Patents

3D shaped packaging product Download PDF

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Publication number
SE2050888A1
SE2050888A1 SE2050888A SE2050888A SE2050888A1 SE 2050888 A1 SE2050888 A1 SE 2050888A1 SE 2050888 A SE2050888 A SE 2050888A SE 2050888 A SE2050888 A SE 2050888A SE 2050888 A1 SE2050888 A1 SE 2050888A1
Authority
SE
Sweden
Prior art keywords
air
shaped packaging
packaging product
laid
blank
Prior art date
Application number
SE2050888A
Other versions
SE545542C2 (en
Inventor
Malmqvist Martin
Törnblom Maria
Original Assignee
Stora Enso Oyj
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Stora Enso Oyj filed Critical Stora Enso Oyj
Priority to CA3186351A priority Critical patent/CA3186351A1/en
Priority to US18/004,503 priority patent/US20230249890A1/en
Priority to CN202180048805.1A priority patent/CN115803266A/en
Priority to EP21837461.9A priority patent/EP4178876A4/en
Priority to PCT/IB2021/056120 priority patent/WO2022009129A1/en
Publication of SE2050888A1 publication Critical patent/SE2050888A1/en
Publication of SE545542C2 publication Critical patent/SE545542C2/en

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Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H27/00Special paper not otherwise provided for, e.g. made by multi-step processes
    • D21H27/10Packing paper
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C51/00Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D65/00Wrappers or flexible covers; Packaging materials of special type or form
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B31MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31BMAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B50/00Making rigid or semi-rigid containers, e.g. boxes or cartons
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B31MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31FMECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31F1/00Mechanical deformation without removing material, e.g. in combination with laminating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00Rigid or semi-rigid containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material or by deep-drawing operations performed on sheet material
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W90/00Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
    • Y02W90/10Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Buffer Packaging (AREA)
  • Nonwoven Fabrics (AREA)

Abstract

A 3D shaped packaging product (20) for cushioning and/or thermal insulation of packaged goods is formed by hot pressing of an air-laid blank (10) comprising natural fibers at a concentration of at least 70 % by weight of the air-laid blank (10) and a thermoplastic polymer binder at a concentration selected within an interval of from 4 up to 30 % by weight of the air-laid blank (10). The 3D shaped packaging product (20) has a density that is less than four times a density of the air-laid blank (10). The 3D shaped packaging product (20) maintains at least a significant portion of the porosity of the air-laid blank (10) even after hot pressing and therefore provides excellent shock absorbing and damping properties and thermal insulation.

Description

3D SHAPED PACKAGING PRODUCT TECHNICAL FIELDThe present embodiments generally relate to three dimensional (3D) shaped packaging products, and inparticular to such 3D shaped packaging products adapted for cushioning and/or thermal insulation ofpackaged goods, and methods of producing such 3D shaped packaging products.
BACKGROUNDWith growing awareness for the environment and humanly induced climate change, the use of single useplastic items and products has come more and more into question. However, despite this concern theuse of these items and products has grown vastly with new trends in lifestyles and consumer habits ofthe last decade. One reason for this is that more and more goods are transported around the globe andthese goods need protection against impact or shock and/or extreme temperatures. A common way ofprotecting the goods is to include cushioning and/or insulating elements or products, such as inserts ofsuitable form into the packaging. These can be made from different materials but are typically made froma foamed polymer, of which expanded polystyrene (EPS) is by far cheapest and most common. ln somecases, the entire packaging can be made out of EPS. One example is transport boxes for food that haveto be kept within specified temperature intervals, such as cold food, e.g., fish, or hot food, e.g., readymeals. EPS is, however, one of the most questioned plastic materials and many brand owners are lookingfor more sustainable solutions for these packaging applications. Many countries have also begun to takelegislative actions against single use plastic items and products, which increases the pressure to find alternative solutions.
More sustainable alternatives to polymer products exist today, such as inserts made by a process knownas pulp molding, where a fiber suspension is sucked against a wire mold by vacuum. Another techniquefor forming such inserts are described in U.S. patent application no. 2010/0190020 and European patentno. 1 446 286, which both concern hot pressing of porous fiber mats produced by the process called air-laying into 3D structures with matched rigid molds or by membrane molding.
The above exemplified methods, however, give products with a limited ability for shock protection andthermal insulation. There is therefore a demand in the market for 3D shaped packaging products forcushioning and/or thermal insulation of packaged goods and that can be manufactured using moreenvironmentally friendly materials than EPS.
SUMMARY lt is an objective to provide 3D shaped packaging products for cushioning and/or therma| insulation ofpackaged goods and methods for production of such 3D shaped packaging products. lt is a particular objective to provide such 3D shaped packaging products that can be manufactured fromnatural fibers.
These and other objectives are met by embodiments of the present invention.
The present invention is defined in the independent c|aims. Further embodiments of the invention aredefined in the dependent c|aims.
An aspect of the invention re|ates to a 3D shaped packaging product for cushioning and/or therma|insulation of packaged goods. The 3D shaped packaging product is formed by hot pressing of an air-laidblank comprising natural fibers at a concentration of at least 70 % by weight of the air-laid blank and athermoplastic polymer binder at a concentration selected within an interval of from 4 up to 30 % by weightof the air-laid blank. The 3D shaped packaging product has a density that is less than four times a densityof the air-laid blank.
Another aspect of the invention re|ates to a method for manufacturing a 3D shaped packaging productfor cushioning and/or therma| insulation of packaged goods. The method comprises hot pressing of amale tool into an air-laid blank comprising natural fibers at a concentration of at least 70 % by weight ofthe air-laid blank and a thermoplastic polymer binder at a concentration selected within an interval of from4 up to 30 % by weight of the air-laid blank to form the 3D shaped packaging product having a 3D shapeat least partly defined by the male tool. The 3D shaped packaging product has a density that is less thanfour times a density of the air-laid blank.
The present invention re|ates to 3D shaped packaging products that maintain at least a significant portionof the porosity of the air-laid blank even after hot pressing. This means that the 3D shaped packagingproducts are highly suitable for cushioning of packaged goods providing excellent shock absorbing anddamping properties. The porosity of the 3D shaped packaging products also give these 3D shapedpackaging products thermally insulating properties and, therefore, they can be used for storage and/ortransport of tempered, such as cold or hot, goods, such as provisions and foodstuff. The 3D shapedpackaging products suitable for cushioning and/or therma| protection are additionally made of environmentally friendly natural fibers in clear contrast to prior art foamed inserts made of polystyreneand other polymers.
BRIEF DESCRIPTION OF THE DRAWINGS The embodiments, together with further objects and advantages thereof, may best be understood bymaking reference to the following description taken together with the accompanying drawings, in which: Fig. 1 is an illustrative embodiment of a cross sectional of 3D shaped packaging product; Fig. 2 schematically illustrates the 3D shaped packaging product in Fig. 1 with different densities indifferent portions of the 3D shaped packaging product; Fig. 3 schematically illustrates hot pressing of an air-laid blank to form the 3D shaped packaging product shown in Fig. 1 prior to a male tool engaging the air-laid blank to produce a cavity; Fig. 4 schematically illustrates hot pressing of an air-laid blank to form the 3D shaped packaging productshown in Fig. 1 when a male tool engages the air-laid blank; Fig. 5 is a schematic illustration of a male tool and a female tool configured to be used in hot pressing ofan air-laid blank to form a 3D shaped packaging product according to an embodiment; Fig. 6 is an illustration and close-up of a male tool that can be used in hot pressing and cutting of an air-laid blank to form a 3D shaped packaging product; Fig. 7 is a flow chart illustrating a method for manufacturing a 3D shaped packaging product forcushioning and/or thermal insulation of packaged goods according to an embodiment; and Fig. 8 is a flow chart illustrating an additional, optional step of the method shown in Fig. 7.
DETAILED DESCRIPTION The present embodiments generally relate to three dimensional (3D) shaped packaging products, and inparticular to such 3D shaped packaging products that are adapted for cushioning and/or thermalinsulation of packaged goods, and methods of producing such 3D shaped packaging products. 3D shaped packaging products of the present embodiments are useful as environmentally more friendlyreplacements to corresponding 3D shaped packaging products made of or from foamed polymers, forinstance expanded polystyrene (EPS). More sustainable alternatives to polymer products have beenproposed in U.S. patent application no. 2010/0190020 and European patent no. 1 446 286, which bothconcern hot pressing of porous fiber mats produced by the process called air-laying into 3D structureswith matched rigid molds or by membrane molding. The 3D shaped packaging products produced in theabove mentioned documents are, however, dense with thin cross sections and have therefore limitedshock absorbing or damping ability and comparatively poor thermal insulation.
The 3D shaped packaging products of the present embodiments are formed by hot pressing of an air-laid blank comprising natural fibers and a binder. An air-laid blank, sometimes also referred to as dry-laidblank, air-laid mat, dry-laid mat, air-laid web or dry-laid web, is formed by a process known as air-laying,in which natural fibers and binders are mixed with air to form a porous fiber mixture. This fiber mixtureconstituting an air-laid blank is characterized by being porous, having the character of an open cell foamand being produced in a so-called dry production method, i.e., no addition of water. The air-laying processwas initially described in U.S. patent no. 3,575,749. The air-laid blank may be in the form as produced inthe air-laying process. Alternatively, the air-laid blank may be in an at least partly processed form, such as by being cut into a given form prior to hot pressing. ln clear contrast to U.S. patent application no. 2010/0190020 and European patent no. 1 446 286, the3D shaped packaging products of the present embodiments formed from air-laid blanks retaincharacteristics of the air-laid blanks even after hot pressing and, therefore, have excellent shockabsorbing and thermally insulating properties. The 3D packaging products could thereby be produced tohave geometries, i.e., 3D shapes, suitable for protection of goods during transport and/or storage. Thepreservation of the porous character of the air-laid blank starting material means that the 3D shapedpackaging products could be used to protect not only consumer goods and products but also heavyequipment against impact. Furthermore, the porous 3D shaped packaging products of the embodimentshave improved thermally insulating properties as compared to compact and dense 3D shaped packagingproducts with thin cross sections. This means that the 3D shaped packaging products can also, oralternatively, be used for storage and/or transport of goods that need to be kept cold, such as cold provisions, or need to be kept hot or warm, such as ready meals.
An aspect of the invention relates to a 3D shaped packaging product 20 for cushioning and/or thermalinsulation of packaged goods, see Fig. 1. The 3D shaped packaging product 20 is formed by hot pressing of an air-laid blank 10, see Figs. 3 and 4, comprising natural fibers at a concentration of at least 70 % byweight of the air-laid blank 10 and a thermoplastic polymer binder at a concentration selected with in aninterval of from 4 up to 30 % by weight of the air-laid blank 10. The 3D shaped packaging product 20 hasa density that is less than four times a density of the air-laid blank 10.
The 3D shaped packaging product 20 of the present embodiments is produced from the air-laid blank 10in a hot pressing process that preserves at least some of the porosity of the air-laid blank 10. Hence, thedensity of the 3D shaped packaging product 20 is less than four times the density of the air-laid blank 10.The prior art hot pressing processes that produce dense 3D shaped packaging products with thin crosssections typically increase the density of the 3D shaped packaging products with several tens of thedensity of the air-laid blank, such as 10 to 50 times. The significant increase in density of the prior art 3Dshaped packaging products means that most of the porosity of the air-laid blank is lost resulting in adense and compact fiber structure. The comparatively lower increase in density according to the inventionin clear contrast preserves the porous structure of the air-laid blank 10 also in the formed 3D shapedpackaging product 20.
The density of the 3D shaped packaging product 20 as used herein is the average or mean density ofthe 3D shaped packaging product 20. This means that the 3D shaped packaging product 20 may containportions or parts 25A, 25B, 25C, 25D, 25E, see Fig. 2, with different porosity and thereby differentdensities. This is due to hot pressing different parts of the air-laid blank 10 at different levels or amountsdue to the shape of a male tool 30 employed in the hot pressing, see Figs. 3 and 4. The different densitiesin the different parts 25A, 25B, 25C, 25D, 25E of the 3D shaped packaging product 20 are schematicallyshown with different gray scale patterns in Fig. 2. For instance, the parts of the air-laid blank 10 alignedwith the protruding structures 32 of the male tool 30 will be pressed and compacted harder as comparedto other parts of the air-laid blank 10. As a consequence, the parts 25C, 25E of the 3D shaped packagingproduct 20 aligned with the protruding structures 32 of the male tool 30 will have higher densities ascompared to other parts 25A, 25B, 25D of the 3D shaped packaging product. The density of the 3Dshaped packaging product 20 is, however, the average or mean density rather than densities of differentparts thereof, and represents the total mass of the 3D shaped packaging product 20 divided by the volumeof the 3D shaped packaging product 20 excluding any cavities 26 in the 3D shaped packaging product20 formed during the hot pressing by the male tool 30 possibly combined with a female tool 50, see Fig.
Hot pressing as used herein indicates that the air-laid blank 10 is exposed to pressure exerted by pressinga male tool 30 or a male tool 30 and a female tool 50 into the air-laid blank 10 while the air-laid blank 10is heated or exposed to heat. Hence, hot pressing implies that the pressing is done at a temperatureabove room temperature, preferably at a temperature at which the thermoplastic polymer binder ismalleable. Hot pressing using heated tools 30, 50 and/or heated air-laid blanks 10 is further describedherein in connection with Figs. 7 and 8. ln an embodiment, the natural fibers are wood fibers. ln a particular embodiment, the natural fibers arecellulose and/or lignocellulose fibers. Hence, in an embodiment, the natural fibers contain cellulose, suchas in the form of cellulose and/or lignocellulose, i.e., a mixture of cellulose and lignin. The natural fibersmay also contain lignin, such as in the form of lignocellulose. The natural fibers may additionally containhemicellulose. ln a particular embodiment, the natural fibers are cellulose and/or lignocellulose pulp fibersproduced by chemical, mechanical and/or chemo-mechanical pulping of softvvood and/or hardwood. Forinstance, the cellulose and/or lignocellulose pulp fibers are in a form selected from the group consistingof sulfate pulp, sulfite pulp, thermomechanical pulp (TMP), high temperature thermomechanical pulp(HTMP), mechanical fiber intended for medium density fiberboard (MDF-fiber), chemo-thermomechanicalpulp (CTMP), high temperature chemo-thermomechanical pulp (HTCTMP), and a combination thereof.
The natural fibers can also be produced by other pulping methods and/or from other cellulosic orlignocellulosic raw materials, such as flax, jute, hemp, kenaf, bagasse, cotton, bamboo, straw or ricehusk.
The air-laid blank 10 comprises the natural fibers in a concentration of at least 70 % by weight of the air-laid blank 10. ln a preferred embodiment, the air-laid blank 10 comprises the natural fibers in aconcentration of at least 72.5 %, more preferably at least 75 %, such as at least 77.5 %, at least 80 %,at least 82.5 %, at least 85 % by weight of the air-laid blank 10. ln some applications, even higherconcentrations of the natural fibers may be used, such as at least 87.5 %, or at least 90 %, at least 92.5%, at least 95 % or at least 96 % by weight of the air-laid blank 10.
The thermoplastic polymer binder is included in the air-laid blank 10 as binder that binds the air-laid blank10 together and preserves its form and structure during use, handling and storage. The thermoplasticpolymer binder may also assist in building up the foam-like structure of the air-laid blank 10. Thethermoplastic polymer binder is intermingled with the natural fibers during the air-laying process forminga fiber mixture. The thermoplastic polymer binder may be added in the form of a powder, but are more often in the form of fibers that are intermingled with the natural fibers in the air-laying process.Alternatively, or in addition, the thermoplastic polymer binder may be added as solution, emulsion ordispersion into and onto the air-laid blank 10 during the air-laying process. This latter technique is most suitable for thin air-laid blanks 10. ln a particular embodiment, the thermoplastic polymer binder is selected from the group consisting of athermoplastic polymer powder, thermoplastic polymer fibers and a combination thereof. ln an embodiment, the thermoplastic polymer binder has a softening point not exceeding a degradationtemperature of the natural fibers. Hence, the thermoplastic polymer binder thereby becomes softened ata process temperature during the hot pressing that does not exceed the degradation temperature of thenatural fibers. This means that the thermoplastic polymer binder becomes malleable and maintain the atleast partly porous structure of the 3D shaped packaging product 20 at a temperature that does not degrade the natural fibers in the air-laid blank 10. ln an embodiment, the thermoplastic polymer binder is or comprises thermoplastic polymer fibers cut ata fixed length, which are typically referred to as staple fibers. lt is generally preferred for the mixing in theair-laying process and, thereby, for the properties of the formed air-laid blank 10 if the length of thethermoplastic polymer fibers is of the same order of magnitude as the length of the natural fibers. Lengthof the thermoplastic polymer fibers and the natural fibers as referred to herein is length weighted averagefiber length. Length weighted average fiber length is calculated as the sum of individual fiber lengthssquared divided by the sum of the individual fiber lengths. ln an embodiment, the thermoplastic polymer binder is or comprises thermoplastic polymer fibers havinga length weighted average fiber length that is selected within an interval of from 75 % up to 300 %,preferably from 80 % up to 250 %, and more preferably from 90 % up to 220 %, such as from 95 % up to200 % of a length weighted average fiber length of the natural fibers. ln a particular embodiment, thethermoplastic polymer fibers have a length weighted average fiber length within an interval of from 1 upto 10 mm, preferably within an interval of from 2 up to 8 mm and more preferably within an interval of from 2 up to 6 mm.
The length weighted average fiber length of the natural fibers is dependent on the source of the naturalfibers, such as tree species they are derived from, and the pulping process. A typical interval of lengthweighted average fiber length of wood pulp fibers is from about 0.8 mm up to about 5 mm. ln an embodiment, the thermoplastic polymer binder is or comprises mono-component and/or bi-component thermoplastic polymer fibers. Bi-component thermoplastic polymer fibers, also known as bicofibers, comprise a core and sheath structure, where the core is made from a first polymer, copolymerand/or polymer mixture and the sheath is made from a second, different polymer, copolymer and/or polymer mixture. ln an embodiment, the thermoplastic polymer binder is or comprises, such as consists of, mono-component thermoplastic polymer fibers made of a material selected from the group consisting ofpolyethylene (PE), ethylene acryiic acid copolymer (EAA), ethyiene-vinyl acetate (EVA), polypropylene(PP), polystyrene (PS), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS),polylactic acid (PLA), polyethylene terephthalate (PET), polycaprolactone (PCL) and copolymers and/ormixtures thereof. ln another embodiment, the thermoplastic polymer binder is or comprises, such asconsists of, bi-component thermoplastic polymer fibers having a core and/or sheath made of a materialor materials selected from the group consisting of PE, EAA, EVA, PP, PS, PBAT, PBS, PLA, PET, PCLand copolymers and/or mixtures thereof. ln a further embodiment, the thermoplastic polymer binder is orcomprises, such as consists of, a combination or mixture of mono-component thermoplastic polymerfibers made of a material selected from the group consisting of PE, EAA, EVA, PP, PS, PBAT, PBS, PLA,PET, PCL and copolymers and/or mixtures thereof and bi-component thermoplastic polymer fibers havinga core and/or sheath made of a material or materials selected from the group consisting of PE, EAA,EVA, PP, PS, PBAT, PBS, PLA, PET, PCL and copolymers and/or mixtures thereof. ln an embodiment, the thermoplastic polymer binder is or comprises a thermoplastic polymer powdermade of a material selected from the group consisting of PE, EAA, EVA, PP, PS, PBAT, PBS, PLA, PET,PCL and copolymers and/or mixtures thereof.
Particular examples of material for the thermoplastic polymer binder that could be used according to thepresent embodiments include PBAT, PBS, PLA, PCL, and copolymers and/or mixtures thereof. ln sucha case, the thermoplastic polymer binder made of these materials is compostable under industrial conditions.
The thermoplastic polymer binder could be made of a single type of thermoplastic polymer fibers, i.e.,made of a same material in the case of mono-component thermoplastic polymer fibers or made of thesame material or materials in the case of bi-component thermoplastic polymer fibers. However, it is also possible to use a thermoplastic polymer binder made of multiple different mono-component thermoplasticpolymer fibers made of different materials and/or multiple different bi-component thermoplastic polymer fibers made of different materials.
Generally, air-laid blanks and 3D shaped packaging products made there from can be recycled if theycan be disintegrated in an opener for this specific purpose and run through the air-laying process againwith the possible addition of additional binder. This is in reality only possible for edge trim and otherprocess rejects that are recycled in-house within the production facility. For consumers and other endusers, this is not an option since there is no air-laying process in existing recycling schemes. A muchbetter option would be if the products produced by or from air-laying could be sorted into one of theexisting recycling fractions, for which there are already functioning collection and recycling systems.Since the majority of the material is made up of wood fibers that could go into a paper or board makingprocess these would be the natural, existing, fractions to collect the air-laid blanks and 3D shapedpackaging products with. With printing papers sensitive to impurities that can cause faults in the printingprocess or dark specs in the paper, the board fraction would typically be the better option. Recycled boardis often used for mid-plies in box boards with several layers or fluting in corrugated board. These are lesssensitive to impurities, even those that decrease the strength of the recycled material.
A prerequisite for a material to be recyclable as board is that it is repulpable i.e., that most of it willdisintegrate into separate fibers when sheared with water in a repulping process and, thus, pass thefollowing screening to give a good yield of usable pulp. The conventional thermoplastic binders used forair-laid blanks attach too well to the cellulose and/or lignocellulose fibers. Hence, these thermoplasticpolymer binders prevent disintegration to a degree that makes the yield of the repulping process far too low to be economically useful.
The thermoplastic polymer materials with high tackiness and low melting points that are often used formono-component fibers and the sheath of bi-component fibers present an additional problem in boardrecycling. These may turn into stickies and render the material classified as unsuitable for recycling inthe repulping process. One way to solve both these problems would be to use a binder that will dissolvein the water of the repulping process i.e., is water soluble at the repulping temperature. At the same timethe binder would need to be thermoplastic with a melting point that does not exceed the degradationtemperature of the natural fibers and it should have a very good adhesion to the natural fibers after beingheated and cooled again. Furthermore, the binder should not have detrimental effects in the board- making process. lt is also an advantage if they are safe to use in food contact applications.
"Repulpability" and "recyclability" in paper or board processes are most widely tested using the PTS-method PTS-RH 021/97 from the German Papiertechnische Stiftung. For board products, the PTS-method tests the recyclability in two steps, where the first is a repulpability test. ln the repulpability test,50 g of material is disintegrated in a standard disintegrator for 20 min at conditions as specified in PTS-method PTS-RH 021/97. The undispersed residue is screened out and its weight is determined. lf theweight of this undispersed residue corresponds to less than 20% of the original weight (50 g), the materialis classified as "recyclable". lf the weight of the undispersed residue is 20-50% of the original weight, thematerial is classified as "recyclable but worthy of product design improvement". The second part of thePTS-method PTS-RH 021/97 for board products is a test for impurities, especially substances thatbecome extremely tacky when heated, in the test to 130°C. ln the board making process, such sticky ortacky substances can attach to machine fabrics and other essential parts of the board machine and causerunability problems and the need for extended, costly, cleaning stoppages. ln the paper and boardindustry, this type of impurities is usually called "stickies". The presence of such stickies in theunscreened, disintegrated sample render the material classified as "non-recyclable due to stickies". Thepresence of other impurities can restrict the usability of the recycled pulp acquired from the material butis not considered totally detrimental.
Hence, in an embodiment, the thermoplastic polymer binder, or at least a part thereof, is water soluble ata repulping temperature selected for repulping the 3D shaped packaging product 20. ln such a case, the3D shaped packaging product 20 could be recycled in a repulping process as mentioned above. Watersoluble as used herein implies that the thermoplastic polymer binder dissolves or disperses in waterduring the repulping process. For instance, the thermoplastic polymer binder may dissolve or disperse inwater at the repulping temperature of the repulping process, i.e., forms a solution or colloidal dispersion,in which the thermoplastic polymer binder exists as single molecules and/or form colloidal aggregates.Water soluble as used herein implies, in an embodiment, a solubility of more than 0.5 g thermoplasticpolymer binder per 100 mL water, preferably at least 1 g thermoplastic polymer binder per 100 mL water,and more preferably at least 5 g thermoplastic polymer binder per 100 mL water, such as at least 10 gthermoplastic polymer binder per 100 mL water. Hence, in an embodiment, the at least a part of thethermoplastic polymer binder that is water soluble preferably has water solubility in accordance withabove.
Examples of such water soluble thermoplastic polymer binders are mono-component and/or bi-component thermoplastic polymer fibers made of a material selected from the group consisting of 11 polyvinyl alcohol (PVA), polyethylene glycol (PEG), poly(2-ethyl-2-oxazoline) (PEOX), polyvinyl ether(PVE), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polymethacrylic acid (PMAA) and copolymersand/or mixtures thereof. ln an embodiment, the thermoplastic polymer binder is or comprises, such as consists of, mono-component thermoplastic polymer fibers made of a material selected from the group consisting of PVA,PEG, PEOX, PVE, PVP, PAA, PMAA and copolymers and/or mixtures thereof. ln another embodiment,the thermoplastic polymer binder is or comprises, such as consists of, bi-component thermoplasticpolymer fibers having a sheath or a sheath and core made of a material or materials selected from thegroup consisting of PVA, PEG, PEOX, PVE, PVP, PAA, PMMA and copolymers and/or mixtures thereof.ln a particular embodiment, at least the sheath of the bi-component thermoplastic polymer fibers is madeof a material selected from the group consisting of PVA, PEG, PEOX, PVE, PVP, PAA, PMAA andcopolymers and/or mixtures thereof. ln such a particular embodiment, also the material of the core of thebi-component thermoplastic polymer fibers could be selected from this group. However, if the core of thebi-component thermoplastic polymer fibers does not soften to become tacky and attach to the naturalfibers in the hot pressing the core may actually be made of a material that are not necessarily watersoluble at the repulping temperature. This means that the core could be made of the previously mentionedthermoplastic polymer materials. Hence, in this particular embodiment, the bi-component thermoplasticpolymer fibers comprise a core component made of a material selected from the group consisting ofpolyethylene PE, EAA, EVA, PP, PS, PBAT, PBS, PLA, PET, PCL and copolymers and/or mixturesthereof and a sheath component made of a material selected from the group consisting of PVA, PEG,PEOX, PVE, PVP, PAA, PMAA and copolymers and/or mixtures thereof. ln a further embodiment, thethermoplastic polymer binder is or comprises, such as consists of, a combination of mono-componentthermoplastic polymer fibers made of a material selected from the group consisting of PVA, PEG, PEOX,PVE, PVP, PAA, PMAA and copolymers and/or mixtures thereof and bi-component thermoplasticpolymer fibers having a core and/or sheath made of a material or materials selected from the groupconsisting of PVA, PEG, PEOX, PVE, PVP, PAA, PMAA and copolymers and/or mixtures thereof. ln an embodiment, the thermoplastic polymer binder is or comprises a thermoplastic polymer powdermade of a material selected from the group consisting of PVA, PEG, PEOX, PVE, PVP, PAA, PMAA andcopolymers and/or mixtures thereof. ln a particular embodiment, the air-laid blank 10 and preferably the 3D shaped packaging product 20 isrepulpable or recyclable preferably as defined according to the PTS-method PTS-RH 021/97 from the 12 German Papiertechnische Stiftung. Hence, in a particular embodiment, the air-laid blank 10 andpreferably the 3D shaped packaging product 20 results in less than 50 % (w/w), preferably less than 20% (w/w) of undispersed residue following disintegration of 50 g of the air-laid blank 10 or 3D shapedpackaging product 20 in a standard disintegrator for a 20 min at conditions as specified in PTS-methodPTS-RH 021/97. ln more detail, the PTS-method PTS-RH 021/97 comprises disintegrating the specimens in line with DINEN ISO 5263-1:2004-12, but using tap water of 40°C. The dilution water is poured over the samplematerial, which are placed in the disintegrator (Standard disintegrator to DIN EN ISO 5263-1:2004-12)without pre-swelling. The sample material is disintegrated at a consistency of 2.5 % o.d. correspondingto a weighed-in amount of 50 g o.d. and a slurry volume of 2 L. The disintegration period is 20 min (60,000revolutions). After disintegrating, the pulp (total stock) is completely transferred to a standard distributor(Standard distributor to ZELLCHEMING Technical Information Sheet ZM V/6/61) and diluted with tapwater to a total volume of 10 L, which corresponds to 0.5 % consistency. The screening is conducted inline with ZELLCHEMING Technical Information Sheet ZM V/18/62 using a perforated plate of 0.7 mmhole diameter. The test device is set to the "low stroke" mode. A test portion of the slurry correspondingto 2 g o.d. (400 ml) is taken out of the distributor and diluted to a total volume of 1000 mL, which is filledinto the fractionator during 30 s and screened for 5 min at a washing water pressure of 0.3 bar. After 5min, the water supply and the membrane displacement motor are cut off. The valve on the retaining ringis opened to drain the water which has gathered below the test chamber. The locking screw is loosenedand the test chamber is tilted upwards. The rear nozzles are covered with one hand to prevent water fromdripping onto the unprotected perforated plate with the residue on it. All residue from the perforated plateis washed into a 2 L tank and dewatered through a filter inserted in a Büchner funnel. The filter is foldedonce and placed in the dryer to dry at 105 °C up to weight constancy. Products are rated as "recyclable"if the disintegration residue does not exceed 20 % in relation to the input and rated as "recyclable, butworthy of product design improvement" if the disintegration residue is from 20 % to 50 % of the input. ln an embodiment, the air-laid blank 10 comprises the thermoplastic polymer binder at a concentrationselected within an interval of from 10 up to 30 %, such as from 15 up to 30 % by weight of the air-laidblank 10. ln a particular embodiment, the air-laid blank 10 comprises more than 15 % but no more than30 % by weight of the thermoplastic polymer binder. For instance, the air-laid blank 10 comprises thethermoplastic polymer binder at a concentration selected within an interval of from 15 or 17.5 up to 30 %by weight of the air-laid blank 10. ln a particular embodiment, the air-laid blank 10 comprises the 13 thermoplastic polymer binder at a concentration selected within an interval of from 15 or 17.5 up to 25 %,such as from 20 up to 25 % by weight of the air-laid blank 10. ln some applications, it may be advantageous to have a comparatively higher concentration of thethermoplastic polymer binder, such as more than 15 % by weight of the air-laid blank 10, in order topreserve the integrity and foam-like structure of the air-laid blank 10 even when not pressing the air-laidblank 10 that hard to get the porous 3D shaped packaging product 20. Thus, if too low concentration ofthermoplastic polymer binder is included, i.e., below 4 % by weight of the air-laid blank 10, the formed3D shaped packaging product 20 may unintentionally disintegrate or fall apart since the combination oftoo low concentration of the thermoplastic polymer binder and a "soft" hot pressing of the air-laid blank10 is not sufficient to keep the structure of the 3D shaped packaging product 20. ln some embodiments, the air-laid blank 10 comprises the thermoplastic polymer binder at aconcentration selected within an interval of from 4 up to 15 % by weight of the air-laid blank 10, preferablywithin an interval of from 5 up to 15 % by weight or the air-laid blank 10, or within an interval of from 7.5up to 15 % by weight of the air-laid blank 10, and more preferably within an interval of from 10 up to 15% by weight of the air-laid blank 10. These embodiments are, in particular, suitable for usage withthermoplastic polymer binders that are water soluble at a repulping temperature selected for repulpingthe 3D shaped packaging product, e.g., for usage with thermoplastic polymer fibers made from a materialor materials selected from the group consisting of PVA, PEG, PEOX, PVE, PVP, PAA, PMAA andcopolymers and/or mixtures thereof. ln an embodiment, the density of the 3D shaped packaging product 20 is equal to or less than three timesthe density of the air-laid blank 10. ln a particular embodiment, the density of the 3D shaped packagingproduct 20 is equal to or less than twice the density of the air-laid blank 10.
Hence, according to the invention the hot pressing of the air-laid blank 10 leads to an increase in densityof the 3D shaped packaging product 20 as compared to the density of the air-laid blank 10 of no morethan 300 %, preferably no more than 250 %, and more preferably no more than 200 %, 150 % or mostpreferably of no more than 100 %.
The hot pressing, however, preferably causes an increase in the density of the 3D shaped packagingproduct 20 as compared to the density of the air-laid blank 10 due to hot pressing of the male tool 30 orthe male tool 30 and the female tool 50 into the air-laid blank 10. The increase in density caused by the 14 hot pressing is preferably at least 10 %, such as at least 12.5 %, at least 15 %, at least 17.5 %, at least20 %, at least 22.5 %, at least 25%, or even higher, such as at least 30 %, at least 40 %, at least 50 %,at least 60 %, at least 70 %, at least 80 %, at least 90 % or at least 100 %. ln various embodiments, the increase in density caused by the hot pressing is at least 12.5 % but nomore than 300 %, such as at least 15 % but no more than 275 %, at least 17.5 % but no more than 250%, at least 20 % but no more than 225 %, such at least 22.5 % but no more than 200 %. ln a particular embodiment, no part of the 3D shaped packaging product 20 formed by hot pressing ofthe air-laid blank 10 has a high density. Hence, the cushioning and/or thermal insulation properties arepreferably achieved for all parts of the 3D shaped packaging product 20. ln an embodiment, no part ofthe 3D shaped packaging product 20 has a density that is more than ten times, preferably more than ninetimes, such as more than eight times, seven times, six times, or five times, and more preferably more than four times, such as three times, or twice, the average density of the air-laid blank 10. ln an embodiment, the density of the air-laid blank 10 is selected within an interval of from 10 to 60 kg/m3.ln an embodiment, the density of the 3D shaped packaging product 20 is selected within an interval offrom 15 to 240 kg/m3. ln an embodiment, the air-laid blank 10 has a thickness of at least 20 mm, preferably at least 30 mm andmore preferably at least 40 mm. Hence, the present embodiments preferably use rather thick air-laidblanks 10 to get 3D shaped packaging products 20 suitable for cushioning and/or thermal insulation evenafter hot pressing. The thickness of the air-laid blank 10 may be selected based on the particular use ofthe resulting 3D shaped packaging product 20, such as based on the cushioning and/or isolationrequirements for the 3D shaped packaging product 20 and/or based on the geometries of the packagedgoods that are to be protected by the 3D shaped packaging product 20. ln an embodiment, the 3D shaped packaging product 20 is configured to protect the packaged goodsfrom electrostatic discharge (ESD). ln such an embodiment, the air-laid blank 10 is electrically conductingor semiconducting. For instance, the air-laid blank 10 could comprise an electrically conducting polymeror electrically conducting fibers to make the air-laid blank 10 and, thereby, the 3D shaped packagingproduct 20 formed by hot pressing the air-laid blank 10, electrically conducting or semiconducting. lnsuch a case, the air laid blank 10 preferably comprises the electrically conducting polymer or fibers at aconcentration of no more than 10 % by weight of the air-laid blank 10, and more preferably of no more than 5 % by weight of the air-laid blank 10. ln an embodiment, a portion of the natural fibers may bereplaced with electrically conducting polymer or fibers. ln another embodiment, the binder is made of, orcomprises, an electrically conducting polymer. ln a further embodiment, these two embodiments arecombined. ln a particular embodiment, the electrically conducting polymer or fibers are carbon fibers.lnstead of, or as a complement to, having electrically conducting polymer or fibers, the air-laid blank 10could comprise an electrically conducting or semiconducting filler, such as carbon black, which, forinstance, could be in the form of an additive to the binder. ln some applications, it may be desirable to seal some or all of the surfaces of the 3D shaped packagingproduct 20, such as by heat, to prevent linting from the surface(s) onto the packaged goods. Surfacesthat are processed with heat in the hot pressing will be sealed and do not need any additional (heat)sealing. The at least one surface to be sealed can be sealed, such as by heat, before or after the hotpressing operation. Hence, in an embodiment, the 3D shaped packaging product 20 comprises at leastone surface 21, 23 that is heat sealed to inhibit linting from the at least one surface 21,23. Fig. 1 illustratesa 3D shaped packaging product 20 having an upper surface 22, a bottom surface 24 and two end surfaces21, 23. A 3D shaped cavity 26 is formed in the upper surface 22 in the hot pressing to thereby impart a3D shape of the 3D shaped packaging product 20. The end surfaces 21, 23 may then be unprocessedfrom the air-laid blank 10 or may have been produced by sawing, cutting or stamping the air-laid blank10 to produce these end surfaces 21, 23. ln such a case, it may be preferred to heat seal these surfaces21 , 23 to prevent or at least suppress or inhibit linting. The upper surface 22, or at least a portion thereof,has been hot pressed so no heat sealing thereof is generally needed. Heat sealing of the bottom surface24 may be applied depending on whether the bottom surface of the air-laid blank 10 has been exposed to any heat during the hot pressing. ln some applications, the 3D shaped packaging product 20, or at least a portion thereof, can be laminatedwith a surface layer, such as a thermoplastic polymer film or non-woven textile. This can both preventlinting and add additional functions to the surface, such as moisture barriers, haptic properties, color anddesigns. The film or non-woven could be made from any common thermoplastic polymer. Examplesinclude the previously mentioned thermoplastic polymer materials for usage as thermoplastic polymerbinders. This layer could be heat laminated or extruded to the air-laid blank 10 and/or laminated directlyonto the 3D shaped packaging product 20. ln an embodiment, the film laminated to at least one surface,or a portion thereof, of the 3D shaped packaging product 20 is electrically conducting or semiconductingto provide ESD protection of the packaged goods. 16 Hence, in an embodiment, the 3D shaped packaging product 20 comprises at least one surface coatedwith a surface layer selected from the group consisting of a linting inhibiting layer, a moisture barrier layer,a haptic layer and a colored layer.
The film, textile or surface layer may be attached to the air-laid blank 10 or the 3D shaped packagingproduct 20 by help of a thin layer of a hotmelt glue, by an additional adhesive film or by its own havingbecome semi-melted and tacky during the heat lamination process. This operation can be performedbefore, after or simultaneously with the hot pressing operation. lf the lamination is performed on at leastone surface of the air-laid blank 10, which is later to be processed by hot pressing, the softening point ofthe surface laminate should not exceed the degradation temperature of the natural fibers of the air-laidblank 10. ln further embodiments, it is possible to apply the surface layer by spraying it onto surface(s) of the 3Dshaped packaging product 20 or the air-laid blank 10. The layer may then contain any substances thatcan be prepared as solutions, emulsions or dispersions, such as thermoplastic polymers; naturalpolymers, such as starch, agar, guar gum or locust bean gum, microfibrillar or nanofibrillar cellulose orlignocellulose or mixtures thereof. The surface layer may in addition comprise other substances, such asemulsifying agents, stabilizing agents, electrically conductive agents, etc. that provide additionalfunctionalities to the surface layer and the 3D shaped packaging product 20.
Any hot pressing operation performed after providing a surface layer should preferably be performed ata temperature where the surface layer is in a semi-melted or malleable state but not in a melted stage. lfthe hot pressing is conducted at a too high temperature at which the surface layer is in a melted stage,the surface layer might delaminate from the surface and the natural fibers may in addition start to degradeif the temperature exceeds their degradation temperature(s).
Another aspect of the embodiments relates to a method for manufacturing a 3D shaped packagingproduct 20 for cushioning and/or thermal insulation of packaged goods, see Figs. 3 to 8. The methodcomprises hot pressing, in step S1, of a male tool 30 into an air-laid blank 10 comprising natural fibers ata concentration of at least 70 % by weight of the air-laid blank 10 and a thermoplastic polymer binder ata concentration selected within an interval of from 4 up to 30 % by weight of the air-laid blank 10 to formthe 3D shaped packaging product 20 having a 3D shape at least partly defined by the male tool 30. The3D shaped packaging product 20 has a density that is less than four times a density of the air-laid blank10. 17 ln an embodiment, step S1 in Fig. 7 comprises hot pressing of a heated male tool 30 into the air-laidblank 10. ln this embodiment, the heated male tool 30 is preferably heated to a temperature selectedwithin an interval of from 120°C up to 210°C, preferably within an interval of from 120°C up to 190°C.Hence, in this embodiment, the heating of the air-laid blank 10 is achieved by usage of a heated maletool 30. The male tool 30 may then comprise heating elements 38 that are preferably controllable heatingelements 38 to heat the male tool 30 to a desired temperature for hot pressing. The temperature of themale tool 30 typically depends on the type of natural fibers and the thermoplastic polymer binder in theair-laid blank 10 and the cycle time of the hot pressing in step S1. However, the above presented interval is suitable for most combinations of natural fibers, thermoplastic polymer binders and cycle times. ln an embodiment, the air-laid blank 10 is positioned on a base platen 40 as shown in Figs. 3 and 4. lnan embodiment, step S1 in Fig. 7 comprises hot pressing of the heated male tool 30 into the air-laid blank positioned on a base platen 40 having a temperature equal to or below ambient temperature. ln these embodiments, the heating of the air-laid blank 10 is achieved by the male tool 30, whereas thebase platen 40 is at ambient temperature, typically room temperature, or may even be cooled. Having abase platen 40 at ambient temperature or even cooled may reduce the risk of heating the air-laid blank10 too much during the hot pressing in step S1, which othen/vise may have negative consequences ofdegrading the natural fibers, melting the thermoplastic polymer binder and destroying the porous structureof the air-laid blank 10 and the formed 3D shaped packaging product 20. lt is, though, possible to have the air-laid blank 10 positioned on a heated base platen 40 during the hotpressing in step S1 even in combination with a heated male tool 30. ln such a case, also the undersideof the air-laid blank 10 facing the heated base platen 40 will be heat sealed during the hot pressing. ln another embodiment, see Fig. 5, step S1 comprises hot pressing of the heated male tool 30 and aheated female tool 50 into the air-laid blank 10 positioned in between the heated male tool 30 and theheated female tool 50 to form the 3D shaped packaging product 20 having the 3D shape at least partlydefined by the male tool 30 and the female tool 50. ln this embodiment, the male tool 30 forms a 3Dshaped cavity 26 in the formed 3D shaped packaging product 20, whereas the female tool 50 comprisesa 3D shaped cavity 52 that defines the outer geometry and 3D shape of the 3D shaped packaging product20. 18 ln an embodiment, both the male tool 30 and the female tool 50 are heated, preferably to a temperatureselected within an interval of from 120°C up to 210°C, preferably within an interval of from 120°C up to190°C. The male tool 30 and the female tool 50 may be heated to the same temperature or to differenttemperatures. ln another embodiment, one of the male tool 30 and the female tool 50 is heated, while the other is at ambient temperature. ln the above presented embodiments, at least one of the tools 30, 50 used in the hot pressing in step S1is heated. ln another embodiment, the method comprises an additional step S10 as shown in Fig. 8. Thisstep S10 comprises heating at least a portion of the air-laid blank 10 prior to hot pressing, in step S1 inFig. 7, of the male tool 30 into the air-laid blank 10.
Hence, rather than heating the male tool 30 and/or any female tool 50, the air-laid blank 10 is heated,preferably prior to the hot pressing operation. The air-laid blank 10 is then preferably heated to atemperature where the thermoplastic polymer binder is in a malleable but not melted state. For mostthermoplastic polymer binders this temperature is within an interval of from 80°C up to 180°C, such asfrom 100°C up to 180°C or from 120°C up to 160°C. Hence, in an embodiment, the air-laid blank 10 is preferably heated to a temperature within the interval of from 80°C up to 180°C. ln this embodiment, the male tool 30 and the base platen 40 or female tool 50 may independently be at ambient temperature, such as room temperature, or cooled.
Alternatively, the embodiment shown in Fig. 8, i.e., heating of the air-laid blank 10, could be combined with usage of a heated male tool 30 or a heated male tool 30 and/or a heated female tool 50. ln an embodiment particularly suitable for producing deep cavities or steep walls, step S1 comprises hotpressing of the male tool 30 comprising at least one cavity-defining structure 32 having a cutting edge 34into the air-laid blank 10, see Fig. 6. ln this embodiment, at least one edge of at least one cavity-definingor protruding structure 32 of the male tool 30 comprises a cutting edge 34. This means that when themale tool 30 is pressed into the air-laid blank 10 in step S1 the at least one cutting edge 34 cuts into theair-laid blank 10. Hence, a simultaneous cutting and pressing operation is achieved. The at least onecutting edge 34 of the at least one cavity-defining structure 32 facilitates forming a well-defined 3D shapedcavity 26 in the formed 3D shaped packaging product 20 and where the cavity 26 is shaped to a desired form, such as to fit a packaged goods in the cavity 26. 19 The hot pressing in step S1 results in 3D shaped packaging products 20 with substantially preservedporosity to be suitable for cushioning and/or thermal insulation. Accordingly, the male tool 30 cannot bepressed too hard into the air-laid blank 10, which othen/vise would lead to too compact and dense 3Dshaped packaging products 20. The shape of the cavity 26 in the 3D shaped packaging product 20 canbe more accurately well-defined if the male tool 30 not only presses into the air-laid blank 10 but alsoperforms a cutting action simultaneously with the hot pressing.
The cutting edge(s) 34 can be achieved by having sharp edges of the one cavity-defining structure(s) 32that act similar to the knives or knife edges, whereas the main surface 36 of the at least one cavity-defining structure(s) 32 presses into the air-laid blank 10. ln an embodiment, each edge 34 of all cavity-defining structures 32 of the male tool 30 are in the form of cutting edges 34, or at least a portion thereof.
The overall 3D shape of the 3D shaped packaging product 20 is at least partly defined by the male tool30 creating at least one cavity 26 within the 3D shaped packaging product 20 and by the optional femaletool 50 that defines at least partly the outer shape of the 3D shaped packaging product 20. The 3D shapeand geometries of the 3D shaped packaging product 20 are at least partly selected based on the shapeof the packaged goods that should be protected by the 3D shaped packaging product 20 or by theintended use of the 3D shaped packaging product 20, such as in the form of a food container, etc. ln an embodiment, step S1 comprises hot pressing of the male tool 30 into the air-laid blank 10 at anaverage pressure equal to or below 200 kPa. ln a particular embodiment, the male tool 30 is hot pressedinto the air-laid blank 10 at a pressure equal to or below 175 kPa, and more preferably equal to or below150 kPa. ln an embodiment, the average pressure is defined as the applied force divided by the area ofthe air-laid blank 10 during hot pressing.
The method may also comprise an additional step of cutting the air-laid blank 10 and/or the 3D shapedpackaging product 20 into a desired shape, such as by a saw, a cutter, or stamping die. This cuttingoperation may be performed prior to the hot pressing, simultaneously with the hot pressing and/or afterthe hot pressing. ln an embodiment, step S1 of Fig. 7 is performed without water. Hence, no water is added during the hotpressing operation. The air-laid blank 10 is preferably at ambient equiiibrium moisture content.
The method described above and shown in Figs. 7 and 8 is suitable to form a 3D shaped packagingproduct 20 according to the present invention.
The embodiments described above are to be understood as a few illustrative examples of the presentinvention. lt will be understood by those skilled in the art that various modifications, combinations andchanges may be made to the embodiments without departing from the scope of the present invention.ln particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible.

Claims (28)

1. 1. A three-dimensional (3D) shaped packaging product (20) for cushioning and/or thermal insulationof packaged goods, wherein the 3D shaped packaging product (20) is formed by hot pressing of an air-laid blank (10) comprisingnatural fibers at a concentration of at least 70 % by weight of the air-laid blank (10) and a thermoplasticpolymer binder at a concentration selected within an interval of from 4 up to 30 % by weight of the air-laid blank (10); and the 3D shaped packaging product (20) has a density that is less than four times a density of theair-laid blank (10).
2. The 3D shaped packaging product according to claim 1, wherein the natural fibers are wood fibers,preferably cellulose and/or lignocellulose fibers, and more preferably cellulose and/or lignocellulose pulpfibers produced by chemical, mechanical and/or chemo-mechanical pulping of softvvood and/orhardwood.
3. The 3D shaped packaging product according to claim 2, wherein the natural fibers are celluloseand/or lignocellulose pulp fibers in a form selected from the group consisting of sulfate pulp, sulfite pulp,thermomechanical pulp (TMP), high temperature thermomechanical pulp (HTMP), mechanical fiberintended for medium density fiberboard (MDF-fiber), chemo-thermomechanical pulp (CTMP), hightemperature chemo-thermomechanical pulp (HTCTMP), and a combination thereof.
4. The 3D shaped packaging product according to any one of claims 1 to 3, wherein the density ofthe 3D shaped packaging product (20) is equal to or less than three times the density of the air-laid blank(10), preferably equal to or less than tvvice the density of the air-laid blank (10).
5. The 3D shaped packaging product according to any one of claims 1 to 4, wherein the density ofthe 3D shaped packaging product (20) is selected within an interval of from 15 to 240 kg/m3.
6. The 3D shaped packaging product according to any one of claims 1 to 5, wherein the density ofthe air-laid blank (10) is selected within an interval of from 10 to 60 kg/m3.
7. The 3D shaped packaging product according to any one of claims 1 to 6, wherein the air-laid blank(10) comprises the thermoplastic polymer binder at a concentration selected within an interval of from 15up to 30 % by weight of the air-laid blank (10), preferably within an interval of from 17.5 up to 30 % by 22 weight of the air-laid blank (10), and more preferably within an interval of from 17.5 up to 25 % by weightof the air-laid blank (10).
8. The 3D shaped packaging product according to any one of claims 1 to 7, wherein the thermoplasticpolymer binder is a thermoplastic polymer binder with a softening point not exceeding a degradationtemperature of the natural fibers.
9. The 3D shaped packaging product according to any one of claims 1 to 8, wherein the thermoplasticpolymer binder is or comprises mono-component thermoplastic polymer fibers made from a materialselected from the group consisting of polyethylene (PE), ethylene acrylic acid copolymer (EAA), ethylene-vinyl acetate (EVA), polypropylene (PP), polystyrene (PS), polybutylene adipate terephthalate (PBAT),polybutylene succinate (PBS), polylactic acid (PLA), polyethylene terephthalate (PET), polycaprolactone(PCL) and copolymers and/or mixtures thereof.
10. The 3D shaped packaging product according to any one of claims 1 to 9, wherein the thermoplasticpolymer binder is or comprises bi-component thermoplastic polymer fibers having a core componentand/or sheath component made from a material or materials selected from the group consisting ofpolyethylene (PE), ethylene acrylic acid copolymer (EAA), ethylene-vinyl acetate (EVA), polypropylene(PP), polystyrene (PS), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS),polylactic acid (PLA), polyethylene terephthalate (PET), polycaprolactone (PCL) and copolymers and/ormixtures thereof.
11. The 3D shaped packaging product according to any one of claims 1 to 8, wherein at least a partof the thermoplastic polymer binder is water soluble at a repulping temperature selected for repulping the3D shaped packaging product (20).
12. The 3D shaped packaging product according to any one of claims 1 to 11, wherein thethermoplastic polymer binder is or comprises mono-component thermoplastic polymer fibers made froma material selected from the group consisting of polyvinyl alcohol (PVA), polyethylene glycol (PEG),poly(2-ethyl-2-oxazoline) (PEOX), polyvinyl ether (PVE), polyvinylpyrrolidone (PVP), polyacrylic acid(PAA), polymethacrylic acid (PMAA) and copolymers and/or mixtures thereof.
13. The 3D shaped packaging product according to any one of claims 1 to 12, wherein thethermoplastic polymer binder is or comprises bi-component thermoplastic polymer fibers having a core 23 component and/or a sheath component made from a material or materials selected from the groupconsisting of polyvinyl alcohol (PVA), polyethylene glycol (PEG), poly(2-ethyl-2-oxazoline) (PEOX),polyvinyl ether (PVE), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polymethacrylic acid (PMAA)and copolymers and/or mixtures thereof.
14. The 3D shaped packaging product according to any one of claims 1 to 13, wherein thethermoplastic polymer binder is or comprises bi-component thermoplastic polymer fibers comprising: a core component made from a material selected from the group consisting of polyethylene (PE),ethylene acrylic acid copolymer (EAA), ethylene-vinyl acetate (EVA), polypropylene (PP), polystyrene(PS), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polylactic acid (PLA),polyethylene terephthalate (PET), polycaprolactone (PCL) and copolymers and/or mixtures thereof; and a sheath component made from a material selected from the group consisting of polyvinyl alcohol(PVA), polyethylene glycol (PEG), poly(2-ethyl-2-oxazoline) (PEOX), polyvinyl ether (PVE),polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polymethacrylic acid (PMAA) and copolymers and/ormixtures thereof.
15. The 3D shaped packaging product according to any one of claims 1 to 14, wherein thethermoplastic polymer binder is or comprises thermoplastic polymer fibers having a length weightedaverage fiber length that is selected within an interval of from 75 % up to 300 %, preferably from 80 % upto 250 %, and more preferably from 90 % up to 220 %, such as from 95 % up to 200 %, of a lengthweighted average fiber length of the natural fibers.
16. The 3D shaped packaging product according to any one of claims 1 to 15, wherein thethermoplastic polymer binder is or comprises thermoplastic polymer fibers having a length weightedaverage fiber length that is selected within an interval of from 1 up to 10 mm, preferably within an intervalof from 2 up to 8 mm, and more preferably within an interval of from 2 up to 6 mm.
17. The 3D shaped packaging product according to any one of claims 1 to 16, wherein the air-laidblank (10) has a thickness of at least 20 mm, preferably at least 30 mm and more preferably at least 40 mm.
18. The 3D shaped packaging product according to any one of claims 1 to 17, wherein the 3D shapedpackaging product (20) comprises at least one surface (21, 23) that is heat sealed to inhibit linting fromthe at least one surface (21, 23). 24
19. The 3D shaped packaging product according to any one of claims 1 to 18, wherein the 3D shapedpackaging product (20) comprises at least one surface coated with a surface layer selected from thegroup consisting of a linting inhibiting layer, a moisture barrier layer, a haptic layer and a colored layer.
20. The 3D shaped packaging product according to claim 19, wherein the surface layer is attached tothe at least one surface of the 3D shaped packaging product (20) by a hotmelt glue and/or by an adhesive film.
21. A method for manufacturing a three-dimensional (3D) shaped packaging product (20) forcushioning and/or thermal insulation of packaged goods, the method comprising hot pressing (S1) of amale tool (30) into an air-laid blank (10) comprising natural fibers at a concentration of at least 70 % byweight of the air-laid blank (10) and a thermoplastic polymer binder at a concentration selected within aninterval of from 4 up to 30 % by weight of the air-laid blank (10) to form the 3D shaped packaging product(20) having a 3D shape at least partly defined by the male tool (30), wherein the 3D shaped packagingproduct (20) has a density that is less than four times a density of the air-laid blank (10).
22. The method according to claim 21, wherein hot pressing (S1) of the male tool (30) comprises hotpressing (S1) of a heated male tool (30) into the air-laid blank (10), the heated male tool (30) is preferably heated to a temperature selected within an interval of from 120°C up to 210°C.
23. The method according to claim 22, wherein hot pressing (S1) of the heated male tool (30)comprises hot pressing (S1) of the heated male tool (30) into the air-laid blank (10) positioned on a baseplaten (40) having a temperature equal to or below ambient temperature.
24. The method according to claim 21, wherein hot pressing (S1) of the male tool (30) comprises hotpressing (S1) of the male tool (30) and a female tool (50) into the air-laid blank (10) positioned in betweenthe male tool (30) and the female tool (50) to form the 3D shaped packaging product (20) having the 3Dshape at least partly defined by the male tool (30) and the female tool (50), at least one of the male tool(30) and the female tool (50) is heated, preferably heated to a temperature selected within an interval offrom 120°C up to 210°C.
25. The method according to claim 21 to 24, further comprising heating (S10) at least a portion of theair-laid blank (10) prior to hot pressing (S1) of the male tool (30) into the air-laid blank (10), preferably heating the air-laid blank (10) to a temperature selected within an interval of from 80°C up to 180°C.
26. The method according to any one of claims 21 to 25, wherein hot pressing (S1) of the male tool(30) comprises hot pressing (S1) of the male tool (30) comprising at least one cavity-defining structure(32) having a cutting edge (34) into the air-laid blank (10).
27. The method according to any one of claims 21 to 26, wherein hot pressing (S1) of the male tool(30) comprises hot pressing (S1) of the male tool (30) into the air-laid blank (10) at an average pressureequal to or below 200 kPa, preferably equal to or below 175 kPa, and more preferably equal to or below150 kPa.
28. The method according to any one of claims 21 to 27, wherein hot pressing (S1) of the male tool(30) comprises hot pressing (S1) of the male tool (30) into the air-laid blank (10) to form the 3D shapedpackaging product (20) as defined in any one of claims 1 to 20.
SE2050888A 2020-07-09 2020-07-14 3D shaped packaging product for cushioning and/or thermal insulation of packaged goods SE545542C2 (en)

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CA3186351A CA3186351A1 (en) 2020-07-09 2021-07-08 3d shaped packaging product from an air-laid blank
US18/004,503 US20230249890A1 (en) 2020-07-09 2021-07-08 3d shaped packaging product from an air-laid blank
CN202180048805.1A CN115803266A (en) 2020-07-09 2021-07-08 3D-shaped packaged products from air laid blanks
EP21837461.9A EP4178876A4 (en) 2020-07-09 2021-07-08 3d shaped packaging product from an air-laid blank
PCT/IB2021/056120 WO2022009129A1 (en) 2020-07-09 2021-07-08 3d shaped packaging product from an air-laid blank

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