WO2020152671A1 - Compostable packaging material - Google Patents

Abstract

Provided herein is compostable and thermoformable laminate, comprising stretchable paper and regenerated cellulose film, and fully compostable packaging material and products made therefrom.

Description

COMPOSTABLE PACKAGING MATERIAL

RELATED APPLICATION

This application claims the benefit of priority of U.S. Provisional Patent Application No. 62/796,104 filed 24 January 2019, the contents of which are incorporated herein by reference in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to a fully compostable packaging material, and more particularly, but not exclusively, to a thermoformable and airtight compostable blank suitable for food packaging and the like.

In an attempt to conform to the global trends in bio-sustainability, sound environmental conduct and community health, the food industry seeks solutions for packaging materials having a limited or nullify carbon footprint and waste load. Biodegradability has been the starting point for most environmentally-aware manufacturers of plastics, however, biodegradable plastic waste still leaves much to be desired, as biodegradable plastic may have the ability to break down into small bits so that microorganisms can consume it, given enough time, but plastic take much longer. Evidently, since the production of plastic, there has been no evidence that plastic completely disappears back into our soil or waters. Moreover, breaking up to small bits is why many animals ingest small biodegradable plastic pieces.

Compostable materials, given composting conditions, will leave essentially no discemable trace in the soil, and their non-gaseous breakdown products can serve as plant/bacteria/fungi food, without toxication. While some compostable materials have been used for food packaging, the mechanical and physical demands of modern packaging techniques pose a difficult challenges, stemming from the limited strength and thermoformability, and high moisture and oxygen permeability of compostable materials.

U.S. Patent Application Publication No. 2016/0288978 provides a package and a method of producing the package adapted to be sealed, comprising arranging a sheet of stretchable paper on a cavity; applying a pressure to the sheet such that a nip is obtained at the rim of the cavity; applying a force to the sheet such that the sheet partly slides into the cavity and partly extends within the cavity to form a package having a body portion and a rim portion formed at the nip; and coating a surface of the rim portion to form a surface for gas-tight sealing.

U.S. Patent No. 10,086,585 provides paper laminate comprising a first stretchable paper layer, a second stretchable paper layer and an intermediate paper layer arranged between the first and the second stretchable paper layer, characterized in that the stretchability (ISO 1924/3) of the first and the second stretchable paper layer is at least 5% in both the machine direction (MD) and the cross direction (CD) and the stretchability (ISO 1924/3) of the intermediate paper layer is less than 4% in the MD and/or the CD.

Regenerated cellulose film, as disclosed in U.S. Patent Nos. 1,961,316 and 2,451,768, has been known and used in the food industry for decades. U.S. Patent No. 9,539,794, teaches a coated film comprising a substantially biodegradable substrate having a biodegradable coating thereon at a coat weight of not more than 12 g/m², as well as useful articles sealed inside a package at least partly comprising such a film, and also a process for producing a coated film comprising providing a substantially biodegradable film substrate and applying a biodegradable coating to the substrate at a coat weight of less than 12 g/m² by means of a hot melt coating step.

Additional background art includes EP2963178, EP3211135, U.S. Patent Nos. 4,681,797, 4,847,148, 5,972,447, 6,177,159, 6,503,588, 6,998,157 and 10,065,779, and U.S. Patent Application Publication Nos. 2010/0003457 and 2016/0340069, and WO 2016/001028.

SUMMARY OF THE INVENTION

Aspects of the present invention are drawn to compostable and thermoformable laminate, comprising stretchable paper and regenerated cellulose film, and fully compostable packaging material and products made therefrom.

According to an aspect of some embodiments of the present invention there is provided a laminate that includes at least a first layer and a second layer, wherein the first layer includes a stretchable cellulosic pulp sheet (e.g., stretchable paper), the second layer includes a regenerated cellulose film (e.g., cellophane); at least one of the layers is coated on at least one side thereof with an substantially impermeable coating, wherein the coating is substantially impermeable to water and oxygen; wherein the laminate is characterized by a thermoforming coefficient of at least 0.15, whereas the thermoforming coefficient being a ratio of a deepest depth to a shortest width of a curved depression made in the laminate without rendering the laminate permeable to water and oxygen; and the laminate is compostable according to at least one of EN 13432 and ASTM D6400.

In some embodiments, the laminate further includes a third layer, the third layer includes a stretchable cellulosic pulp sheet, and the second layer is interposed between the first and the third layer.

In some embodiments, the laminate further includes a fourth layer, the fourth layer includes a regenerated cellulose film, and positioned over the third layer. In some embodiments, any one of the third layer and the fourth layer is coated on at least one side thereof with the substantially impermeable coating.

In some embodiments, the laminate further includes a lamination adhesive between each two adjacent layers.

In some embodiments, the grammage of the lamination adhesive ranges 1-5 g/m².

In some embodiments, the stretchable cellulosic pulp sheet (e.g., stretchable paper) is characterized by a stretchability (ISO 1924/3) of at least 5 % in both the machine direction (MD) and the cross direction (CD).

In some embodiments, the grammage of the first layer and the third layer if present, each independently ranges 50-300 g/m².

In some embodiments, the grammage of the second layer and the fourth layer if present, each independently ranges 20-80 g/m².

In some embodiments, the grammage of the substantially impermeable coating ranges 0.5-10 g/m².

According to another aspect of some embodiments of the present invention there is provided a container formed from the laminate presented herein.

In some embodiments, the container is formed by a thermoforming process.

In some embodiments, the container exhibits a flanged rim and further includes a removable (e.g., peelable) cover, the cover is affixed to the flanged rim and seals the container by heat or adhesion.

In some embodiments, removable cover is coated on at least the inner surface thereof with a substantially impermeable coating.

In some embodiments, the removable cover is compostable according to at least one of EN 13432 and ASTM D6400.

In some embodiments, the removable cover includes regenerated cellulose film.

In some embodiments, the container further includes a single or a plurality of objects packaged therein.

In some embodiments, the object is selected from the group consisting of a foodstuff and a drug.

In some embodiments, the container further includes a modified atmosphere enclosed therein.

According to yet another aspect of some embodiments of the present invention there is provided a roll of the laminate provided herein.

In some embodiments, the roll further includes a core cylinder. In some embodiments, the core cylinder is compostable according to at least one of EN 13432 and ASTM D6400.

In some embodiments, the roll is wrapped in a sheath.

In some embodiments, the sheath is compostable according to at least one of EN 13432 and ASTM D6400.

Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.

In the drawings:

FIGs. 1A-D present schematic illustrations of a side-view (side-cut) of the laminate, according to some embodiments of the present invention, wherein FIG. 1A shows laminate 10 having first layer 11 made of STP, second layer 12 made of RCF placed on top of layer 11, and optional lamination adhesive 13 affixing the layers to one another, FIG. IB shows laminate 10 having first and third layers 11 made of STP, second layer 12 made of RCF interposed between first and third layers 11, and optional lamination adhesive 13 affixing the layers to one another, FIG. 1C shows laminate 10 having first and third layers 11 made of STP, second and fourth layers 12 made of RCF interposed between first and third layers 11 and on top of third layer 11, and optional lamination adhesive 13 affixing the layers to one another, and FIG. 1C shows laminate 10 as in FIG. 1C, with an additional lacquer coating, whereas at least one of each of the layers further includes a substantially impermeable coating on at least one face thereof (not shown in FIGs 1A-D); FIG. 2 presents a schematic illustration of a packaging tray made from the laminate in a standard thermoforming operation, according to some embodiments of the present invention, wherein tray 20 is show in a top-view on the left, and a side-view on the right, noting packaging depth 21, length of shortest side of the packaging 22, and flanged rim 23, whereas the thermoforming coefficient is a ratio between packaging depth 21 and length of shortest side of the packaging 22;

FIG. 3 presents a schematic illustration of roll 30, wherein laminate 31, corresponding to the laminate presented herein, is wound around core 32 (protective sheath not shown); and

FIG. 4 presents a schematic illustration of an individual sealable container 40, according to some embodiments of the present invention, which is manufactured by conventional packaging operations, having peelable heat sealed cover 41 with pull tab 42, heat-sealable on flanged rim 43 that formed a part of tray 44.

DESCRIPTION OF SOME SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to a fully compostable packaging material, and more particularly, but not exclusively, to a thermoformable and airtight compostable blank suitable for food packaging and the like.

The principles and operation of the present invention may be better understood with reference to the figures and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

More and more consumers and manufacturers are looking for ways to avoid using plastic products and adding to the growing amount of plastic waste ending up in landfill and the oceans. While some are going the zero waste route, others are looking for eco-friendly plastic alternatives for everyday products. One of those alternatives is products made out of biodegradable or compostable materials. Although biodegradable plastics and compostable plastics are not new alternatives to traditional petroleum-based plastics, there still seems to be some confusion surrounding“greener” plastic products, particularly the confusion between biodegradable plastic and compostable plastic.

Biodegradable refers to a material breaking down with the help of microorganisms. To be labelled a biodegradable plastic, there is no time limit set on when the product breaks down and whether these plastics leave toxic residue behind. In the context of embodiments of the present invention, the term“compostable” is distinguished from the term“biodegradable” and refers to a material capable of breaking down, at the same rate as cellulose, into carbon dioxide, water, and biomass, given compost conditions. Compostable material is characterized in that it disintegrates and becomes indistinguishable in compost and leave no toxic material behind. Alternatively, in the context embodiments of the of the present invention, a compostable material is such that conforms to the internationally acceptable standards, such as the EN 13432 and ASTM D6400 standards for compostability.

Presently known laminates (a sheet of material made by bonding two or more sheets or layers) that are thermoformable and thus useful for packaging, are known to comprise non- compostable elements; even laminates that are based on compostable paper include plastic plies, added to confer thermoformability, mechanical strength, impermeability and seal. Despite their relatively small non-compostable plastic content, such as PE or PET, these known laminates do not conform to any of the internationally acceptable standards for compostable materials, and are therefore considered as non-compostable materials. While conceiving the present invention, the inventor has contemplated a thermoformable laminate that would conform to the internationally acceptable standards, and still be thermoformable, namely mechanically suitable and safe for use for food packaging.

Compostable and thermoformable laminate:

While reducing the present invention to practice, the present inventor has surprisingly found that interposing a ply of a regenerated cellulose film, also known in its generic name as cellophane or as a line of products under the trademarked name Cellophane™, between two layers of stretchable and thermoformable paper, affords a fully compostable and yet also thermoformable laminate, which can be used to manufacture containers for food and other products. The finding is surprising since until the time of the invention, all thermoformable laminates were made with thermoformable materials, which are also non-compostable materials, such as polyethylene (PE) or polyethylene terephthalate (PET), while Cellophane™, or regenerated cellulose film, is known to be thermoset and not thermoplastic, thus it is not thermoformable. Nevertheless, the laminate having two layers of stretchable paper, sandwiching a ply of cellophane, was found to be suitable for thermoforming processes.

Thus, according to an aspect of embodiments of the present invention, there is provided a laminate that includes at least a first layer and a second layer, wherein:

the first layer is made substantially from a stretchable paper, as this type of material is described hereinbelow, and referred to as“STP”; the second layer is made substantially from a regenerated cellulose film, referred to herein as“RCF”, as this type of material is described hereinbelow;

at least one of the layers is coated on at least one side thereof with a substantially impermeable coating, the coating is substantially impermeable to water and oxygen, as this property of the material is described hereinbelow;

the laminate is characterized by a thermoforming coefficient of at least 0.15, the thermoforming coefficient being a ratio of a deepest depth to a shortest width of a curved depression made in the laminate without rendering the laminate permeable to water and oxygen, as described in details hereinbelow; and

the laminate is compostable in the sense of at least one of EN 13432 and ASTM D6400, which are the most internationally acceptable standards for compostability.

As used herein, the term“thermoformable” refers to the capacity of the laminate to undergo industrial shape forming processes, which include any process that is known in the art for turning a two dimensional laminate (sheet; blank) into a three dimensional object, as these are known in the art, without limitation, as thermoforming, thermo-and-stamp forming, deep draw, press form and vacuum forming. Some of these processes are known by other names and may be construed as equivalent and encompassed under the term“thermoformable” to describe the input material for any of these processes.

In some embodiments of the present invention, the laminate further includes a third layer, which is also made substantially from the stretchable paper. In such embodiments, the second layer of RCF is interposed between the first layer (STP) and the third layer (STP).

In some embodiments of the present invention, the laminate further includes a fourth layer, which is also made substantially from RCF, and positioned over the third layer (STP).

In embodiments in which the laminate includes more than the first layer and the second later, also any one of the third layer and fourth layer may be coated on at least one side thereof with the substantially impermeable coating.

As described hereinbelow, the laminate may further include a lamination adhesive between each of the layers.

FIGs. 1A-D present schematic illustrations of a side-view (side-cut) of the laminate, according to some embodiments of the present invention, wherein FIG. 1A shows laminate 10 having first layer 11 made of STP, second layer 12 made of RCF placed on top of layer 11, and optional lamination adhesive 13 affixing the layers to one another, FIG. IB shows laminate 10 having first and third layers 11 made of STP, second layer 12 made of RCF interposed between first and third layers 11, and optional lamination adhesive 13 affixing the layers to one another, FIG. 1C shows laminate 10 having first and third layers 11 made of STP, second and fourth layers 12 made of RCF interposed between first and third layers 11 and on top of third layer 11, and optional lamination adhesive 13 affixing the layers to one another, and FIG. 1C shows laminate 10 as in FIG. 1C, with an additional lacquer coating, whereas at least one of each of the layers further includes a substantially impermeable coating on at least one face thereof (not shown in FIGs 1A-D).

According to embodiments of the present invention, the laminates presented herein and products, such as containers produced therefrom, are essentially devoid of a non-compostable materials, namely contains less than 10 % non-compostable materials, less than 5 %, less than 2 %, less than 1 %, or less than 0.5 % non-compostable materials by weight of the total weight of the laminate or a product produced therefrom. Specifically, the laminates presented herein and products, such as containers produced therefrom, are essentially devoid of PE and/or PET.

Stretchable cellulosic pulp sheet:

According to embodiments of the present invention, the thermoformable and compostable laminate comprises at least two layers (plies) of a stretchable sheet made of a cellulosic pulp. For the sake of brevity, the term“cellulosic pulp sheet” is referred to herein as “paper”, and the two terms are used interchangeably. This form of paper contributes to both the thermoformability and compostability of the laminate and any product prepared therefrom, and its physico-mechanical properties essentially determines the thermoformability and compostability of the laminate and a product prepared therefrom, while the other plies and coating present in the laminate contribute, and essentially determine other properties of the laminate and a product prepared therefrom, such as permeability.

Stretchable cellulosic pulp sheet (paper) has been introduced to the food packaging industry decades ago, in publications that include U.S. Patent Nos. 2,169,505, 2,245,014, 2,267,320, and 3,483,071. More recently, stretchable paper has been further developed to a level where it can be used as a thermoformable material (hence stretchable and thermoformable paper, or STP), as disclosed by the firm BillerudKorsnas AB of Sweden, in, for example, WO 2018/185216, WO 2013/135215, WO 2018/185213, WO 2018/178070, WO 2017/148921, WO 2016156454, WO 2016/130071, WO 2015/189130, WO 2015/117954, WO 2015/117954 and WO 2015/082268, and U.S. Patent No. 10,086,585, each of which is incorporated herein by reference.

In the context of embodiments of the present invention, the stretchable paper used for at least two layers (plies), separated by an airtight ply of RCF in the laminate provided herein, is characterized by the ability to thermoform into 3D-shapes in a standard thermoforming process. In general, the ability to thermoform can be defined in physico-mechanical terms per given thickness of the material. For example, the stretchable paper that is used in the laminate provided herein confers the ability to process the laminate into 3D packaging products using machine feeders that feed the laminate into the thermoforming line fitted with pressure and heating plates, with or without an air pressure and/or vacuum fittings, while the machine settings depend on the forming die design and the laminate composition and thickness.

The stretchable and thermoformable paper (STP) essentially determines the formability of the laminate. According to some embodiments, the STP is characterized by about 15 % elongation in the machine direction, and about 10 % elongation in the cross direction, whereas the size of the packaging being manufactured from a laminate that includes the STP determines the achievable depth, and the length on the shortest side of the packaging determines the maximal possible depth. In some embodiments, the packaging depth (PD; mm) versus the length of shortest side of the packaging (SS; mm) with a curved bottom can be calculated according to the linear formula PD = a · SS, wherein“a”, referred to herein as the thermoforming coefficient, is at least 0.15, and typically ranges 0.15-0.50, 0.15-0.30 or 0.15-0.20; hence, the larger formed area (footprint), the higher depth can be achieved. Maximum depth is reached using a curved bottom shape, whereas a flat bottom of the packaging will reduce the achievable packaging depth, and the extent of the depth reduction is determined by the bottom area. This thermoforming coefficient corresponds to the Draw Ratio discussed hereinbelow.

FIG. 2 presents a schematic illustration of a packaging tray made from the laminate in a standard thermoforming operation, according to some embodiments of the present invention, wherein tray 20 is show in a top-view on the left, and a side-view on the right, noting packaging depth 21, length of shortest side of the packaging 22, and flanged rim 23, whereas the thermoforming coefficient is a ratio between packaging depth 21 and length of shortest side of the packaging 22.

A stretchable paper, according to embodiments of the present invention, is selected to exhibit a grammage of 50-300 g/m² according to ISO 536, or 50-140 g/m², 70-140 g/m², or 80- 140 g/m², or 90-140 g/m², or 70-130 g/m², or 80-130 g/m², or 90-130 g/m², or 100-130 g/m², 100-150 g/m², 100-180 g/m², 100-200 g/m², or 100-200 g/m²; wherein“grammage” is an art- recognized term that refers to the amount of a material coating a surface, as well as a correlation to the thickness of a substantially homogeneously thick sheet of a material. The paper is also characterized by a stretchability (according to ISO 1924/3) in the machine direction (MD) of above 5 %, 6 %, 7 %, 8 %, 9 %, 10 %, 11 %, 12 %, or above 15 %. The stretchability (according to ISO 1924/3) in the cross direction (CD) of the paper is typically above 5 %, 6 %, 7 %, 8 %, 9 % or above 10 %. The tensile energy absorption (TEA) is often considered to be a paper property that best represents the relevant strength of the paper wall, whereas the tensile strength is the maximum force that a paper will withstand before breaking. In the standard test ISO 1924/3, a stripe having a width of 15 mm and a length of 100 mm is used with a constant rate of elongation. The TEA of the paper used in the laminate provided herein, according to ISO 1924/3 in the MD of the paper, may be, for example at least 300 J/m², such as at least 330 J/m², such as at least 350 J/m². Further, the TEA index according to ISO 1924/3 in the MD of the paper may be, for example at least 3.4 J/g, such as at least 3.5 J/g. The TEA index according to ISO 1924/3 in the CD of the stretchable paper of the laminate aspect may be, for example, at least 2.4 J/g, such as at least 2.6 J/g. The stretchable paper of the laminate aspect may be bleached, which means that its brightness may be least 78 % or at least 80 % according to ISO 2470-1; preferably, the brightness of a bleached stretchable paper of the laminate aspect is at least 83 %.

In some embodiments of the present invention, the stretchable paper is a paper as described in EP 3211135, the contents of which is incorporated herein by reference.

As presented herein, although the laminate comprises at least one ply of regenerated cellulose film, which is known for being thermoset, and thus non-thermoformable, the stretchable and thermoformable paper, or STP, surprisingly confers essentially the same thermoformability to the laminate prepared therewith, wherein said thermoformability is governed substantially by the total thickness of the laminate, the breadth and depth of the cavity that it is depressed into, the heat and/or pressure (direct die press or by vacuum) that the laminate is exposed thereto during the thermoforming process, and other machine related variable.

In the context of embodiments of the present invention, the stretchable paper is used in its pristine form, namely uncoated and not comprising any additional reinforcement elements, plies or structural additives, and is referred to as stretchable and thermoformable paper (STP).

Regenerated cellulose film:

According to some embodiments of an aspect of the present invention, the term “regenerated cellulose film”, or RCF, refers to a polymeric cellulose film made from the cellulose from wood, cotton, hemp, or other sources. The raw material of choice is called dissolving pulp, or regenerated cellulose, which is white like cotton and contains about 92-98% cellulose. The cellulose is dissolved in alkali in a process known as mercerization. It is aged several days, and treated with carbon disulfide to make an orange solution called viscose, or cellulose xanthate. The viscose solution is then extruded through a slit into a bath of dilute sulfuric acid and sodium sulfate to reconvert the viscose back into cellulose. The film is then passed through several more baths, one to remove sulfur, one to bleach the film, and one to add glycerin to prevent the film from becoming brittle. Typical RCF has a CAS number of 9005-81- 6. RCF may further include a coat of another substance, such as PVDC, nitrocellulose or wax to make it impermeable to air and/or water vapor. It may also be coated with other materials to make it heat sealable for automated wrapping machines.

Manufacturers and trademarks of RCF include Innovia, the owner of the trademark Cellophane™, and the manufactures of cellulosic film for applications that include tapes and labels, photographic film, coatings for paper, glass, and plastic. Several Innovia Cellophane™ products include Cellophane™ P00 - uncoated regenerated cellulose film (RCF) with no softeners incorporated; Cellophane P25 - uncoated RCF with high mechanical strength; Cellophane™ DM/DMS - RCF with one side coated with nitrocellulose by a solvent process; Cellophane LST - RCF with both sides coated with nitrocellulose by a solvent process; and Cellophane™ XSB - RCF with both sides coated with polyvinylidene chloride (PVDC) by a solvent process.

As widely known in the plastic and wrapping/packaging, while RCF may be suitable for many packaging applications, it is not thermoplastic, but rather thermoset, and thus its use for thermoformable blanks and/or thermoformable laminates has not been implemented or considered hitherto. It is noted herein that the addition of an RCF ply to an already thermoformed product, or its use as a lid for a thermoformed product, is not considered as being part of a thermoformable laminate, at least in the context of embodiments of the present invention.

In the context of embodiments of the present invention, the RCF can be used as a RCF pristine ply, or as a pre-coated ply. The coating may be for adding advantageous property to the thermoformed product made from the presently claimed laminate - for example, a coat selected to add oxygen impermeability, moisture impermeability, physico-mechanical strength, adhesion and tackiness, and glossy finish.

According to some embodiments of the present invention, the RCF is a ply (layer) that is interposed between two plies of STP. In some embodiments the interposed RCF layer comprises coated RCF. In some embodiments the interposed coated RCF layer is coated on one side/face thereof, in some embodiments it is coated on both sides thereof, in some embodiments it is coated on both sides thereof by two different coating materials.

It is noted herein that in order to maintain the compostability of the laminate provided herein, it is made from compostable materials, hence, non-compostable forms of cellulose are not used for the interposed layer of RCF. For example, in some embodiments, cellulose esters, such as cellulose acetate (CAc), the co-esters cellulose acetate -propionate (CAP), and cellulose acetate-butyrate (CAB) are excluded from the scope of the RCF layer. Like cellophane cellulose esters are made from cellulose but have very different properties. Unlike cellophane, cellulose esters are thermoplastic, that is, they will soften and melt when heated. Similarly excluded is nitrocellulose (NC), also called cellulose nitrate, which is the oldest thermoplastic commercialized under the trademarks Parkesine, Xylonite and Celluloid.

The RCF, according to embodiments of the present invention, is selected to exhibit a grammage of 20-80 g/m², or 50-140 g/m², 30-80 g/m², or 40-80 g/m², or 50-80 g/m², or 60-80 g/m², or 70-80 g/m², or 20-30 g/m², or 20-40 g/m², 20-50 g/m², 20-60 g/m², or 20-70 g/m².

In some embodiments of the present invention, the RCF, the STP or both, is coated with an oxygen/moisture impermeable material.

Barrier coating:

In the context of some embodiments of the present invention, the term“substantially impermeable” refers to a material characterized by the ability to substantially block the passage of another substance therethrough, as measured or determined by a widely-accepted standard. For example, in some embodiments, the thermoformable and compostable laminate presented herein is substantially impermeable to oxygen and moisture (water vapor). Such impermeability can be afforded by using a barrier coating, as described below. The substantially impermeable coating is also referred to herein and in the industry as“barrier”, as in“oxygen barrier” and/or “water vapor barrier”.

For example, oxygen transmission rate, or OTR of the presently provided laminate can be determined using the ASTM D3985-17 set of standards. OTR is a widely used determinant of the packaging protection afforded by barrier materials. It is not, however, the sole determinant, and additional tests, based on experience, may also be used to correlate packaging performance with OTR. It is suitable as a referee method of testing, provided that the purchaser and the seller have agreed on sampling procedures, standardization procedures, test conditions, and acceptance criteria. This test method covers a procedure for determination of the steady-state rate of transmission of oxygen gas through plastics in the form of film, sheeting, laminates, coextrusions, or plastic-coated papers or fabrics. It provides for the determination of (i) oxygen gas transmission rate (OTR), (ii) the permeability (permeance) of the laminate or film to oxygen gas (PO2), and (iii) oxygen permeability coefficient (RΌ2) in the case of homogeneous materials. ASTM standards that are relevant in the context of gas permeability, include D1434, a test method for determining gas permeability characteristics of plastic film and sheeting; D1898, practice for sampling of plastics; E691, practice for conducting an interlaboratory study to determine the precision of a test method; and ASTM F1927, a test method for determination of oxygen gas transmission rate, permeability and permeance at controlled relative humidity through barrier materials using a coulometric detector.

ASTM F3136-15 is a standard test method for oxygen gas transmission rate through plastic film and sheeting using a dynamic accumulation method. OTR is determined hereby as a determinant of packaging functionality afforded by packaging materials for a wide variety of packaged products including food, pharmaceuticals and medical devices. In some applications, sufficient oxygen must be allowed to permeate into the package, while in others, the oxygen ingress must be minimized to maintain product quality. Other ASTM standard methods to measure the oxygen transmission rate are described in Standard Test Method D3985 and Standard Test Method F2622, as these test methods cover a procedure for determination of the transmission rate of oxygen gas through plastics in the form of film, sheeting, laminates, coextmsions, coated or uncoated papers or fabrics: D3985 is a test method for oxygen gas transmission rate through plastic film and sheeting using a coulometric sensor; E177 is a practice for use of the terms precision and bias in ASTM test methods; E691 is a practice for conducting an interlaboratory study to determine the precision of a test method; F2622 is a test method for oxygen gas transmission rate through plastic film and sheeting using various sensors; and F2714 is a test method for oxygen headspace analysis of packages using fluorescent decay.

According to embodiments of the present invention, the substantially impermeable coating is substantially impermeable to oxygen according to ASTM D3985-17, and/or ASTM D1434, and/or ASTM D1898, and/or ASTM E691, and/or ASTM F1927, and/or ASTM, and/or ASTM F3136-15, and/or ASTM D3985, and/or ASTM F2622, and/or ASTM D3985, and/or ASTM E177, and/or ASTM E691, and/or ASTM F2714.

Another key property of the laminate provided herein is its moisture impermeability, or water vapor transmission rate (WVTR). ASTM D1653-13 is a set of standard test methods for water vapor transmission of organic coating films. One of the factors affecting the performance provided by a coating is its capability of resisting or aiding the passage of water vapor. In some services, for example, exterior wood and masonry, the coating has to allow moderate amounts of water vapor to pass through the film without damage to it. Hence, the water vapor transmission characteristics of coatings are important in assessing their performance in practical use. The purpose of these test methods is to obtain values of water vapor transfer through coatings that range in permeability from high to low. These values are also for use in design, manufacture, and marketing the presently disclosed laminate. The water vapor transmission is not a linear function of film thickness, temperature or relative humidity. Values of water vapor transmission rate (WVT) and water vapor permeance (WVP) can be used in the relative rating of coatings only if the coatings are tested under the same closely controlled conditions of temperature and relative humidity, and if their thicknesses are equal. Test Method A, or the Dry Cup Method, is the preferred test method for obtaining values that relate to conventional dwellings where high relative humidity is not anticipated, while Test Method B, or the Wet Cup Method, is the preferred test method for obtaining values that relate to applications where high relative humidity is anticipated in the vicinity of the barrier material. In general, the more permeable a coating is to the passage of moisture as is typical of many water-reducible coatings, the greater its affinity for water and the greater the increase in transmission when tested in and exposed to high humidity. Absorption of water may make a coating less dense, thus allowing moisture to diffuse easily and cause a much higher moisture vapor transmission rate (WVTR), than would occur in drier environments. These test methods cover the determination of the rate at which water vapor passes through films of paint, varnish, lacquer, and other organic coatings. The films may be free films or they may be applied to porous substrates. A similar, but more generally applicable test method is Test Methods ASTM E96 which should be considered when other materials are involved. Agreement should not be expected between results obtained by different methods or test conditions. The method that most closely approaches the conditions of use should be selected. There are instruments on the market that purport to measure water vapor transmission of films more easily and rapidly than the methods described in Test Methods D1653 and E96. They run essentially the same kinds of tests as in the ASTM methods, but do so instmmentally. However, it appears that no side-by-side tests have been run comparing results from measurements with such instruments to these ASTM methods for precision and accuracy. The ASTM standards include: ASTM D823, practices for producing films of uniform thickness of paint, varnish, and related products on test panels; ASTM D1005, test method for measurement of dry-film thickness of organic coatings using micrometers; ASTM D1193, specification for reagent water; ASTM D4708, practice for preparation of uniform free films of organic coatings; ASTM E96, test methods for water vapor transmission of materials; and ASTM E104, practice for maintaining constant relative humidity by means of aqueous solutions.

According to embodiments of the present invention, the substantially impermeable coating is substantially impermeable to water vapor according to ASTM D1653-13, and/or ASTM E96, and/or ASTM D1653, and/or ASTM D823, and/or ASTM D1005, and/or ASTM D1193, and/or ASTM D4708, and/or ASTM E104.

According to embodiments of the present invention, the substantially impermeable coating is selected to be suitable for coming in contact with dry or moist food, and/or drugs, and/or any oxygen- and/or moisture- sensitive substance, as this coating is preferably the only element in the laminate presented herein, that comes in contact with the food, drug, sensitive substance, according to some embodiments of the invention. Hence, according to some embodiments of the present invention, at least one side of the laminate presented herein, preferably the side that comes in contact with food, is coated with a substantially impermeable coating (barrier), and preferably, the substantially impermeable coating is selected from suitable food contact materials, and more preferably, selected from materials that comply with the framework Regulation No. 1935/2004(EC), and/or the Code of Federal Legislation (CFR): 21 CFR 174 - 21 CFR 190 (USA).

Additional information regarding packaging material with substance barrier properties can be found in the literature, e.g. in a review article by Valentina Siracusa [Siracusa, V.,“ Food Packaging Permeability Behaviour: A Report”, International Journal of Polymer Science, 2012, Article ID 302029, DOI: 10.1155/2012/302029]

As there are several industrial standards available for the user, the present invention is directed at the impermeability property which is suitable and/or required from the product being produced from the presently provided laminate, as such suitability and/or requirement can be achieved by an appropriately selected coating material, and application thereof in the appropriate amount/thickness that affords the suitable and/or required impermeability level.

In the context of embodiments of the present invention, the thermoformable and compostable laminate provided herein is characterized by an OTR that ranges from 1.0 to 200 cm³/m² in 24 hours at 0 % relative humidity, as determined by, e.g., the ASTM F1927 standard.

In the context of embodiments of the present invention, the thermoformable and compostable laminate provided herein is characterized by a WVTR that ranges from 0 to 40 g/m² in 24 hours at 38 °C and 90 % relative humidity, as determined by, e.g., the ASTM E96 standard.

In the context of some embodiments of the present invention, the laminate presented herein includes at least one layer having a substantially impermeable coating having a grammage that ranges 0.5-10 g/m², or 1-5 g/m², or 1-3 g/m², or 2-4 g/m².

According to some embodiments of the present invention, the laminate presented herein further includes an exterior substantially impermeable coating, referred to herein as“lacquer”, having a grammage that ranges 0.2-7 g/m², particularly in the context of a container comprising the same.

The abovementioned OTR and WVTR values are obtainable by using organic coatings in an amount and composition that would not diminish the composability of the laminate or products produced therefrom. For example, the abovementioned OTR and WVTR values are obtainable by using PVDC coating at a grammage (an amount) that ranges 0.1-5 g/m². It is noted herein that oxygen impermeability typically encompasses water vapor impermeability; thus, in the context of embodiments of the present invention, the optional oxygen barrier materials are also considered as water vapor barrier materials. Exemplary barrier materials may include non-compostable substances, however, their use in the presently disclosed compostable laminates is limited to such amounts that are well within the allowable margins of the standards acceptable in the art. Alternative barrier materials, which are contemplated in some embodiments of the present invention, include, without limitation, silica-coated PET, dry ethylene vinyl alcohol (EVOH), typical coextmsion EVOH, liquid crystal polymer, extruded or coated PVDC, dry MXD6 nylon, coextmsion of MXD6 nylon, polyacrylonitrile, polyethylene naphthalate (PEN) polyester, wet amorphous nylon, dry amorphous nylon, dry nylon 6 or 66, wet nylon 6 or 66, 25-45% crystallinity PET, and amorphous PET, provided that the non-compostable materials are present in the laminate in an amount that complies with the acceptable standards for compostability, as discussed herein.

Alternative barrier materials, which are contemplated in some embodiments of the present invention, are presented, without limitation, in Table 1 below, listing the materials and their oxygen and water vapor permeability.

Table 1

Additional information pertaining to barrier materials for packaging can be found in, for example, Lange, J. et al., Recent innovations in barrier technologies for plastic packaging - A Review: Packaging Technology and Science, 2003, 16(4), pp. 149-158, doi:10.1002/pts.621, which is incorporated herein by reference.

Lamella adhesion:

The manufacture of laminates is a relatively simple continuous process of coating and bonding. Specific processes differ primarily by how the adhesive is applied and converted from a liquid to a solid. There are several laminating processes that can be easily adapted to production. These are generally classified as either wet or dry laminating processes.

According to some embodiments of the present invention, adhesion of the various lamella to each other can be achieved, optionally, by using a lamination adhesive. Lamination adhesive can be classified by application type, namely solvent borne, solventless (100 % solids), aqueous-based, and radiation curable (100 % solids or combination with solvent).

According to embodiments of the present invention, the lamination adhesive can be a one-part or a two-part lamination adhesive composition, and further can be a solvent-based, an aqueous-based or a solventless lamination adhesive composition, and further can be suitable for a wet- or a dry- laminating process.

Lamination adhesive can also be classified by performance level or chemistry, namely polyether urethane (aqueous, solvent, and solventless), polyester (solvent based), polyester urethane (aqueous, solvent, and solventless), and acrylic (aqueous or solvent).

Briefly, in dry bond laminating, a liquid adhesive is coated on a substrate, dried with heat and air flow, and then laminated to a second substrate via a heated compression nip. Suitable adhesive types include, without limitation, polyurethane solutions, dispersions and emulsions, acrylic solutions, dispersions and emulsions, water-based polyvinyl alcohol, ethylene vinyl acetate copolymers, and silicone-based solutions, dispersions and emulsions. In the hot melt seal coating approach, low viscosity hot melt adhesives are applied to substrate, and then laminated to a second substrate via a heated compression nip. Suitable adhesive types include, without limitation, ethylene vinyl acetate, modified polyolefin, and polyesters solutions, dispersions and emulsions. In the cold seal approach, a liquid adhesive is applied, dried with heat and air, and then bonded only with slight pressure (formulated so that tack to non-cold seal surfaces is minimized). Suitable adhesive types include, without limitation, synthetic rubber, acrylic and natural rubber.

Briefly, in dry bond laminating, the adhesive is applied to one substrate, usually by roller coating or air knife. The coated substrate is then nipped with another substrate, and the resulting laminate may then be left to air dry or passed through a heated oven to remove solvent and build bond strength. The types of adhesive used for wet lamination include, without limitation, waterborne natural products, such as starch and dextrin or waterborne synthetic latex products, such as polyvinyl acetate, acrylic, etc., and reactive liquids, such as polyurethanes or polyesters. Wet lamination via waterborne or solvent based adhesives is typically used for applications where at least one substrate is porous (e.g., paper, cardboard, textiles) to facilitate drying. Once cured, bond strength is generally high enough to cause failure or tearing of the porous substrate. Most often, waterborne synthetic latex adhesives are utilized for wet bonding because of their high initial strength and fast drying characteristics when applied to porous substrates.

Additional information regarding lamination adhesive and processes of using the same is widely available and understood by a person with average skills in the art of producing laminates.

Commercially available lamination adhesives include, without limitation, SunLam™ NS- 2033A/HA-306, Herberts lk-LF 190 X#, and Mydrin k -LF-194.

The grammage of the lamination adhesive is present between two layers in an amount (grammage) that ranges 1-5 g/m², or 2-4 g/m², or 2-3 g/m². The amount of the lamination adhesive is typically determined by the manufacturer thereof and by the particular application and intended use of the laminate, as would be appreciated by any person of ordinary skills in the art.

A roll of laminate:

Aspects of some embodiments of the present invention include a form of providing the laminate disclosed herein to a user in a machine-read form, such as a roll. The roll comprises a core (typically a cylindrical tube), a laminate sheet of a given fixed width, corresponding to, and typically equal or shorter than the length of the core, and length of a few to tens of meters, wound (wrap) around the core. In some embodiments, the core of the roll is compostable. The roll may further include a protective sheath, wherein the sheath may also be compostable, according to some embodiments of the present invention.

FIG. 3 presents a schematic illustration of roll 30, wherein laminate 31, corresponding to the laminate presented herein, is wound around core 32 (protective sheath not shown).

The roll of the laminate presented herein can be mounted on an automatic thermoforming machine as the input feed of packaging material to be turned into 3-dimensional objects, such as trays, contained and the likes.

3D containers:

While the laminate provided herein is essentially two-dimensional sheet-like structure, it is highly suitable for manufacturing three-dimensional objects, such as containers and packaging products, particularly for the food and other sensitive product industries. As a fully compostable product, a container made from the presently provided laminate can be composted without harming the environments, as well as contributing to the effort of minimizing the carbon footprint of the related industry.

According to some aspects of embodiments of the present invention, there is provided a container made entirely or substantially from the laminate presented herein.

In yet another aspect of embodiments of the present, there is provided a sealed container, wherein the container is made entirely or substantially from the laminate presented herein, and it cover, or seal, is made from any suitable material, or alternatively, the cover is also made from compostable material. Since the cover can easily be separated from the container, the cover can be recycled or discard separately from the container, while in embodiments where the cover and the container are both compostable, both can be handled together, e.g., composted after use.

Depending on the application and intended use of the container, the laminate may comprise more than two layers of STP and RCF. For example, in typical applications for the food industry, the laminate may comprise four layers of alternating paper/RCF, each affixed to the other using any suitable lamination adhesive, having the outwards-facing (bottom) paper layer coated with lacquer or any other form of protective finish, and at least the inwards-facing (top) RCF layer coated with a barrier coating (see, for example, FIG. ID).

In general, any container produced from the laminate provided herein, can further include a cover, a seal or a lid; the cover is for providing a sealed environment entrapped therein during the manufacturing and filling the container with any intended contents, afforded by adhesion of the cover to flanged rim of the container. Typically, the cover is made from a film having at least one side thereof coated with the substantially impermeable coating, as described hereinabove. Further typically, the cover is peelable and can be affixed to the flanged rim by heat (heat seal) and/or by an adhesive. Additional information pertaining to the manufacturing of thermoformed containers and sealed containers is widely available to the skilled artisan of the field, and can be found, for example, in U.S. Patent Nos. 4,771,935, 5,062,569, 5,393,032 and 6,032,800 and U.S. Patent Application Publication Nos. 2004/0251161, 20150021338 which are incorporated by reference as if fully set forth herein.

FIG. 4 presents a schematic illustration of an individual sealable container 40, according to some embodiments of the present invention, which is manufactured by conventional packaging operations, having peelable heat sealed cover 41 with pull tab 42, heat-sealable on flanged rim 43 that formed a part of tray 44.

The ability to manufacture 3-dimensional objects, such as containers and trays, from the laminates presented herein, depends primarily on the stretchability and thermoformability of the laminate, which stems substantially from the stretchability and thermoformability of the STP used therein. The deeper or taller the object is, the heavier the starting thickness (grammage; gauge) of laminate is required. Allowing the object, or any feature therein, to be narrower than it is tall will thin the laminate at a much steeper rate.

The draw ratio of an object made from the laminate presented herein is a key parameter in any thermoforming process. The object has a finite amount of surface area that needs to be covered by a flat two-dimensional laminate. When the laminate is heated and forced over or into a mold, it must stretch to conform to that shape. As the laminate stretches it thins out, and local design features on the mold may cause the sheet to thin at a greater rate than in adjacent areas. Thus, the draw ratio can be described numerically if the surface area can be calculated. The formula for expressing the draw ratio is as follows:

Draw Ratio = the surface area of the finished object / the footprint of the finished object. For example, for a tray of 10 cm x 12 cm x 2 cm deep, the Draw Ratio will be:

Surface Area = 2(10 cm x 2 cm) + 2(12 cm x2 cm) + 10 cm x 12cm = 40 cm + 48 cm + 120 cm = 208 cm;

Footprint = 10 cm x 12 cm = 120 cm; and

Draw Ratio = 208 cm/120 cm = 1.7.

If the desired ending wall thickness of the tray is 0.1 cm, the draw ratio is used as follows to estimate the starting thickness of the sheet:

Draw Ratio x Desired Finished Gauge = Minimum Starting Gauge; or

1.7 x 0.1 cm =0.17 cm assuming perfect material distribution.

The above example ignores the effect that a specific features on the mold (i.e.. a localized severe draw like a sharp comer) may have on the thinning of the laminate, however, the draw ratio is designed to allow the designer to come“in the ball park” when calculating the necessary starting gauge.

It is generally advantageous to avoid a sharp three-sided corner by using a radius or chamfer. The radius at the bottom of the draw is most critical. The deeper the object, the larger the radius or chamfer required. The key to good object design in thermoforming is understanding the need for a proper size radius or chamfer. These features are typically needed to allow for object’s strength, retention of material thickness, and/or esthetics. One of the most difficult features in thermoforming is a three-sided sharp comer in a female mold. This feature accentuates the draw ratio because it forces the material to over the three walls as it is pushed into the corner. The laminate appears to stretch and thin out at a geometric rate, usually causing the material to either thin to an unacceptable ending gauge or actually tear and create a hole in the object. A common design solution is to use radii and/or a chamfers on the object, preventing the laminate from having to continue deeper into the comer, thus arresting the thinning that would normally occur. The other advantage of radii and chamfers is that they distribute stress over a larger area than a sharp 90 degree comer. A chamfer does not distribute the stress as well as a radius, but it gives the designer the option of sharp comers at the transition points of the chamfer. Where a three-sided comer does occur, one large radius with a chamfer or smaller radius on the other edges is often sufficient to solve the thinning and strength problems that occur. As the draw ratio gets larger the radii will almost always have to be increased.

There are many thermoforming techniques and mold designs used to help the laminate stretch as uniformly as possible. A skilled and competent artisan of the field (a thermoformer) will be able to implement them in a project with any reasonable draw ratio.

The process for which the presently disclosed laminates are suitable for, include any thermoforming process, including, without limitation, vacuum forming, pressure forming, twin- sheet pressure forming and the likes.

Vacuum forming, as this term is referred to herein, is a process of evacuating air from the sealed space between the heated laminate and the mold, thus allowing atmospheric pressure to force the laminate to conform to the contour of the mold. This process is typically used for containers and trays, and non-critical appearance products.

Pressure forming, as this term is referred to herein, is a process of applying compressed air (20-120 p.s.i.) to the heated laminate, thus forcing it to conform to the contour of the mold; evacuation of the air between the sheet and the mold is required. This process is typically used for containers and trays, and high appearance products.

Twin-sheet pressure forming, as this term is referred to herein, is a process of injecting compressed air (20-120 p.s.i.) between two hot sheets, thus forcing it to conform to the contour of each of two molds mounted opposed to each other. Evacuation of the air between the sheet and the mold is required.

Aspects of some embodiments of the present invention include a sealed container having packaged therein an article, a foodstuff, a drug, or any other single or plurality of objects, wherein the container is formed from the laminate provided herein. It is typical to form and fill the packaging, made from the laminate provided herein, at the same manufacturing process, namely the container is thermoformed, then the contents is placed therein, and thereafter the container is sealed with the cover, with or without modifying the atmosphere in the container.

Accordingly, aspects of some embodiments of the present invention include a sealed container having, e.g., a foodstuff, a drug or a substance, single or plurality of objects, that is/are sensitive to ambient atmosphere, contained therein, and further comprising a modified atmosphere enclosed therein; wherein the foodstuff is advantageously engulfed in the modified atmosphere for a time period that depends, inter alia, on the substantial impermeability of the cover seal and the container. Modified atmosphere is the practice of modifying the composition of the internal atmosphere of a package (commonly food packages, drugs, etc.) in order to improve the shelf life. The need for this technology for food arises from the short shelf life of food products such as meat, fish, poultry, and dairy in the presence of oxygen. In food, oxygen is readily available for lipid oxidation reactions. Oxygen also helps maintain high respiration rates of fresh produce, which contribute to shortened shelf life. From a microbiological aspect, oxygen encourages the growth of aerobic spoilage microorganisms. Therefore, the reduction of oxygen and its replacement with other gases can reduce or delay oxidation reactions and microbiological spoilage. Oxygen scavengers may also be used to reduce browning due to lipid oxidation by halting the auto-oxidative chemical process. The modification process generally lowers the amount of oxygen (O2) in the headspace of the package. Oxygen can be replaced with nitrogen (N2), a comparatively inert gas, or carbon dioxide (CO2). A stable atmosphere of gases inside the packaging can be achieved using active techniques, such as gas flushing and compensated vacuum, or passively by designing“breathable” films, or selective semi-permeable barriers.

The laminate provided herein is suitable for printing over its exposed surfaces before and/or after the packaging operation (thermoforming, filling and sealing), by selecting an exterior coating receptive to ink, or by selecting ink suitable for printing thereon. Thus, aspects of some embodiments of the present invention include printable compostable and thermoformable laminates.

It is expected that during the life of a patent maturing from this application many relevant compostable and thermoformable laminates will be developed and the scope of the phrase “compostable and thermoformable laminate” is intended to include all such new technologies a priori.

As used herein the term“about” refers to ± 10 %.

The terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to".

The term“consisting of’ means“including and limited to”.

The term "consisting essentially of" means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure. As used herein, the phrases "substantially devoid of" and/or "essentially devoid of" in the context of a certain substance, refer to a composition that is totally devoid of this substance or includes less than about 5, 1, 0.5 or 0.1 percent of the substance by total weight or volume of the composition. Alternatively, the phrases "substantially devoid of" and/or "essentially devoid of" in the context of a process, a method, a property or a characteristic, refer to a process, a composition, a structure or an article that is totally devoid of a certain process/method step, or a certain property or a certain characteristic, or a process/method wherein the certain process/method step is effected at less than about 5, 1, 0.5 or 0.1 percent compared to a given standard process/method, or property or a characteristic characterized by less than about 5, 1, 0.5 or 0.1 percent of the property or characteristic, compared to a given standard.

The term“exemplary” is used herein to mean“serving as an example, instance or illustration”. Any embodiment described as“exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments.

The words“optionally” or“alternatively” are used herein to mean“is provided in some embodiments and not provided in other embodiments”. Any particular embodiment of the invention may include a plurality of“optional” features unless such features conflict.

As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases“ranging/ranges between” a first indicate number and a second indicate number and“ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween. As used herein the terms“process” and "method" refer to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, material, mechanical, computational and digital arts.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below find experimental and/or calculated support in the following examples.

EXAMPLES

Reference is now made to the following examples, which together with the above descriptions illustrate some embodiments of the invention in a non limiting fashion.

Example 1

A compostable laminate

A proof of concept of some embodiments of the present invention was carried out by preparing a four-layer laminate having alternating plies of STP and RCF, wherein the bottom layer of the laminate is seen as the outwards-facing side in the context of a container formed therefrom, and the top layer of the laminate is seen as the inwards-facing side in the context of the container.

42 cm wide stretchable and thermoformable paper (STP) was purchased from BillerudKorsnas AB, Sweden; Product type uncoated FibreForm®. The FibreForm® line of products is characterized by high stretchability and thermoformability, and meets the EN 13432 and ASTM D6400 composting norms. Grammage for the bottom layer was about 150 g/m², and the grammage for the third layer was also about 150 g/m².

42 cm wide PVDC-coated cellophane (PVDC-coated RCF) was purchased from Futamura, Japan (formerly Innovia, England); Product type NatureFlex™ NK Matt, made of 97 percent renewable content (ASTM D6866 Carbon Testing) and meets the EN 13432 and ASTM D6400 composting norms. Grammage for the second layer was about 30 g/m², and the grammage for the top (fourth) layer was also about 30 g/m².

The lamination adhesive that was selected for affixing the lamella is a commonly used two-part solventless adhesive, used in an amount of about 4 g/m².

The lacquer that was selected for sealing the out-facing side of the laminate is a commonly used PVDC-based lacquer, used in an amount of about 1 g/m².

Machine for forming the laminate is a LAMIFLEX™ lamination machine by Soma Spol. S.R.O., Czech Republic.

The procedure for forming the 4-layers laminate was conducted sequentially, wherein the substrate for the first run is the first layer, the substrate for the second run was a laminate comprising the first layer and the second layer, and so on.

Example 2

A food packaging

The laminate described in Example 1 was used to form a lidded food packaging container in the shape of a tray. The lid was cut from the same PVDC-coated RCF that was used for the interposed layer and the inwards-facing layer of the laminate.

The laminate was loaded as a 42 cm wide roll on a Multivac™ automatic tray sealer machine (Model R535) as well as a roll of impermeable barrier-coated RCF (about 30 g/m²) to be used as a peelable heat sealed cover (lid) for the tray.

Procedure for forming and filling the trays followed standard Multivac™ user manuals.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

All publications, patents, patent applications and standards mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting. In addition, any priority document(s) of this application is/are hereby incorporated herein by reference in its/their entirety.

Claims

WHAT IS CLAIMED IS:

1. A laminate comprising at least a first layer and a second layer, wherein:

said first layer comprises a stretchable cellulosic pulp sheet;

said second layer comprises a regenerated cellulose film;

at least one of said layers is coated on at least one side thereof with an substantially impermeable coating, said coating is substantially impermeable to water and oxygen;

the laminate is characterized by a thermoforming coefficient of at least 0.15, said thermoforming coefficient being a ratio of a deepest depth to a shortest width of a curved depression made in the laminate without rendering the laminate permeable to water and oxygen; and

the laminate is compostable according to at least one of EN 13432 and ASTM D6400.

2. The laminate of claim 1, further comprising a third layer, said third layer comprises said stretchable cellulosic pulp sheet, and said second layer is interposed between said first and said third layer.

3. The laminate of claim 2, further comprising a fourth layer, said fourth layer comprises said regenerated cellulose film, and positioned over said third layer.

4. The laminate of any one of claims 2-3, wherein any one of said third layer and said fourth layer is coated on at least one side thereof with said substantially impermeable coating.

5. The laminate of any one of claims 1-4, further comprising a lamination adhesive between each two adjacent layers.

6. The laminate of claim 5, wherein a grammage of said lamination adhesive ranges 1-5 g/m².

7. The laminate of any one of claims 1-6, wherein said stretchable cellulosic pulp sheet is characterized by a stretchability (ISO 1924/3) of at least 5 % in both the machine direction (MD) and the cross direction (CD).

8. The laminate of any one of claims 1-7, wherein a grammage of said first layer and said third layer if present, each independently ranges 50-300 g/m².

9. The laminate of any one of claims 1-7, wherein a grammage of said second layer and said fourth layer if present, each independently ranges 20-80 g/m².

10. The laminate of any one of claims 1-7, wherein a grammage of said substantially impermeable coating ranges 0.5-10 g/m².

11. A container formed from the laminate of any one of claims 1-10.

12. The container of claim 11, formed by a thermoforming process.

13. The container of any one of claims 11-12, exhibiting a flanged rim and further comprising a removable cover, said cover seals the container by adhesion to said flanged rim.

14. The container of claim 13, wherein said removable cover is coated on at least the inner surface thereof with a substantially impermeable coating.

15. The container of claim 13, wherein said removable cover is compostable according to at least one of EN 13432 and ASTM D6400.

16. The container of claim 13, wherein said removable cover comprises regenerated cellulose film.

17. The container of any one of claims 11-16, further comprising a single object or a plurality of objects packaged therein.

18. The container of claim 17, wherein the object is selected from the group consisting of a foodstuff and a drug.

19. The container of any one of claims 11-18, further comprising a modified atmosphere enclosed therein.

20. A roll of the laminate of any one of claims 1-10.

21. The roll of claim 20, further comprising a core cylinder.

22. The roll of claim 20, wherein said core cylinder is compostable according to at least one of EN 13432 and ASTM D6400.

23. The roll of claim 20, being wrapped in a sheath.

24. The roll of claim 20, wherein said sheath is compostable according to at least one of EN 13432 and ASTM D6400.