Packaging materials

Abstract

Polymer substrates containing or composed of polymer components, and A barrier coating layer formed on one or both sides of the substrate. Includes, The polymer component is selected from the group consisting of polyhydroxyalkanoate polymers or copolymers, polybutylene succinate or its copolymers, polylactic acid, polybutylene adipate terephthalate, and mixtures thereof. The barrier coating layer 51-99% by weight, preferably 90-99% by weight, more preferably 95-98% by weight, of polymer components selected from the group consisting of polyhydroxyalkanoate polymers or copolymers, milk or leguminous plant-derived proteins, polylactic acid, polybutylene succinate or its copolymers, starch, chitosan, carrageenan, pectin, alginate, lipids, polyacrylic polymers, polyurethanes, cellulose or chemically modified cellulose and mixtures thereof, and A filler selected from the group consisting of layered double hydroxides, nanocellulose, silicates, clay, and mixtures thereof, in an amount of 49-1% by weight, preferably 1-10% by weight, and more preferably 2-5% by weight. A multilayer packaging material containing (weight percentage is based on 100 parts by weight of polymer components and fillers).

Description

[Technical Field]

[0001] The present invention relates to a multilayer packaging material comprising a polymer substrate and at least one barrier layer, and more particularly to a multilayer packaging material used for packaging confectionery products. [Background technology]

[0002] In food packaging, barrier coatings are necessary and widely used to preserve the sensory properties of food. Barrier properties in packaging materials, particularly those for confectionery products, include low permeability to oxygen (O2) and water vapor, as well as low permeability to volatile aromatic compounds and low light transmission. Specifically, for packaging materials used for confectionery products, a barrier permeability of 100 cc / m³ was measured under conditions of 23°C and 0% relative humidity. 2 Less than 24 hours, or preferably 0.1 cc / m³ 2 • Oxygen permeability (OTR) of less than 24 hours, and 10 g / m² at 38°C and 90% RH. 2 Less than 24 hours, or preferably 0.1 g / m 2 It is desirable to achieve a water vapor transmission rate (WVTR) of less than 24 hours.

[0003] There is a demand for packaging materials that are environmentally sustainable, compostable in diverse environments, and easily recyclable. The objective of this invention is to provide multi-layer packaging using multiple materials, which maintain biodegradability and compostability while ensuring a high level of protection currently lacking in bio-based and biodegradable materials. This goal is achieved by adding all natural additives / materials so that no harmful substances remain in the soil or compost during the biodegradation process.

[0004] Furthermore, there is a need for packaging materials that possess the necessary barrier properties and environmental sustainability, as well as mechanical properties that enable use with modern high-speed packaging machines such as flow pack / flow wrap machines and twist-wrap machines. Particularly desirable mechanical properties include tensile strength and puncture resistance.

[0005] The object of the present invention is to provide a multilayer packaging material that meets the above requirements. [Overview of the Initiative]

[0006] In view of the above objectives, the subject of the present invention is a multilayer packaging material as defined in the appended claims.

[0007] The dependent claims relate to preferred embodiments of the present invention.

[0008] Further features and advantages of the packaging material of the present invention will become apparent from the following detailed description with reference to the accompanying drawings, which are provided as non-limiting examples. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing the layer arrangements of several embodiments (a) to (f) of a packaging material in which the multilayer surface layer has heat-sealing properties. [Figure 2] This is a schematic cross-sectional view showing the layer arrangement in embodiments (a) to (c) of the present invention. This multilayer structure includes a surface layer having cold-seal properties. [Figure 3] A preferred example of a composite co-extruded substrate is shown. [Figure 4] A preferred example of a composite co-extruded substrate is shown. [Figure 5] A preferred example of a composite co-extruded substrate is shown. [Figure 6] A preferred example of a composite co-extruded substrate is shown. [Figure 7] A preferred example of a composite co-extruded substrate is shown. [Figure 8] A preferred example of a composite co-extruded substrate is shown. [Figure 9] Further, more specific embodiments are shown. [Figure 10] Further, more specific embodiments are shown. [Modes for carrying out the invention]

[0010] The present invention relates to a packaging material having a multilayer structure and includes a base material 1. The base material 1 is a film or sheet made of a (bio)degradable polymer or a blend of (bio)degradable polymers.

[0011] (Bio)degradable polymers are selected from the group consisting of polyhydroxyalkanoates or their copolymers, polybutylene succinate or its copolymers, polylactic acid, polybutylene adipate terephthalate, and mixtures thereof.

[0012] The reference to a sheet includes a thermoformed or thermoformable sheet.

[0013] The polyhydroxyalkanoate (PHA) used as the base material 1 includes medium-chain PHA having 6 to 14 carbon atoms in the monomer unit, is soft and elastomeric, and has a low melting point (typically 50 to 170 °C, preferably 100 to 160 °C). However, the term PHA also includes short-chain PHA, long-chain PHA, and / or mixtures thereof.

[0014] Examples of poly(hydroxyalkanoate) polyesters that can be used within the scope of the present invention include poly(3-hydroxybutyrate) (3HB), poly(4-hydroxybutyrate) (4HB), and poly(3-hydroxyvalerate) (3HV). Particularly preferred are copolymers of hydroxybutyrate and hydroxyvalerate or hydroxyhexanoate, having a melting point of 120 to 160 °C, including poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBH), poly(3-hydroxy-co-4-hydroxybutyrate), and their copolymers. PHBH and PHBV are preferred.

[0015] Also included are PHA blends containing PHA (preferably poly(3-hydroxybutyrate-co-4-hydroxybutyrate)) and a biodegradable polymer selected from cellulose, starch or starch acetate, poly(lactic acid), and polycaprolactone.

[0016] The polybutylene succinate (PBS) copolymers include poly(1,4-butylene succinate-co-adipate), poly(1,4-butylene succinate 1,4-butylene azelate), poly(1,4-butylene succinate 1,4-butylene terephthalate), poly(1,4-butylene succinate-co-1,4-1,4-butylene sebacate 1,4-butylene terephthalate), poly(1,4-butylene adipate-co-1,4-butylene succinate-co-1,4-butylene terephthalate), and poly(1,4-butylene azelate 1,4-butylene succinate-co-1,4-butylene terephthalate). Polyhydroxyalkanoate-polybutylene succinate copolymers are also included.

[0017] References to films or sheets of (bio)degradable polymers do not exclude the presence of additives conventionally included in commercially available films or sheets, such as plasticizers, antioxidants, fillers, etc., within the film or sheet.

[0018] In particular, and optionally, the substrate 1 can include particulate fillers that improve barrier properties, such as layered double hydroxides (LDH), particularly hydrotalcite or hydrotalcite-like minerals, clay, nanocellulose, and mixtures thereof. When contained in the substrate, these fillers are dispersed in the polymer matrix and are usually contained in an amount of 0.5 to 10% by weight relative to the polymer matrix.

[0019] In one embodiment, the polymer component of the substrate consists of a polyhydroxyalkanoate polymer or copolymer, polybutylene succinate, or a blend of polyhydroxyalkanoate and polybutylene succinate. The blend preferably contains 50-70% by weight of polyhydroxyalkanoate and 30-50% by weight of polybutylene succinate per 100 parts by weight of the polymer component, and more preferably the substrate further contains 10% by weight or less of a filler per 100 parts by weight of the polymer component, the filler being selected from the group consisting of layered double hydroxides (LDHs), particularly hydrotalcite or hydrotalcite-like minerals, clay, nanocellulose, starch, and mixtures thereof.

[0020] In one embodiment, the substrate 1 is a co-extruded composite film or sheet comprising a core layer 3 and a skin layer 5 that is thinner than the core layer and disposed on one or preferably both sides of the core layer. In this embodiment, the core layer is preferably a polymer film or sheet made of a polyhydroxyalkanoate polymer or copolymer, preferably PHBH or PHBV, or polybutylene succinate or mixtures thereof.

[0021] The core layer of a co-extruded film or sheet, or the substrate as a single-layer film, may be a blend of PHA with polylactic acid up to 40% by weight of PHA to improve the torsional strength of the substrate. A blend of PHBH and PBS can be used to improve the stretchability of the PHBH film.

[0022] In embodiments of the co-extruded composite film, the core layer 3 comprises a filler dispersed in a polymer matrix, the filler being selected from layered double hydroxides, particularly hydrotalcite or hydrotalcite-like minerals, preferably in an amount of 0.5 to 10% by weight relative to the polymer matrix, and also comprising cellulose nanocrystals, preferably in an amount of 0.5 to 3% by weight. The coating layer is a co-extruded coating mainly composed of, or substantially composed of, polymer components selected from polyhydroxyalkanoate polymers or copolymers, polybutylene succinate and its copolymers, and mixtures thereof. The surface layer prevents or limits the potential migration of additives from the core layer. The polymer of the surface layer may be the same as or different from the polymer of the core layer.

[0023] The aforementioned co-extruded composite films or sheets are intermediate products suitable for further processing to be coated with a barrier layer or other layer, as described herein, and these are included within the scope of the present invention.

[0024] Figures 3 to 8 show non-limiting examples of co-extruded composite substrates used according to the present invention.

[0025] Depending on the melting point of the polymer used, the substrate can be heat-sealed.

[0026] The packaging material of the present invention comprises a barrier layer 7 on one or both sides of the base material.

[0027] As used herein, the term “barrier layer” refers to a structural layer that provides a barrier against water vapor, oxygen, odor, or carbon dioxide. It may also provide grease resistance, moisture resistance, and / or water absorption resistance. The barrier layers described herein with reference to the substrates employed in the present invention have also been found to improve the mechanical properties of the material (e.g., tensile strength, tear strength, impact strength, or burst strength). In some embodiments, the disclosed barrier layers impart torsional deformation retention, cold-formability, and thermoformability to the packaging material while maintaining the intrinsic material properties of the substrate.

[0028] In some embodiments, the barrier layer is heat-sealable by employing a low-seal-temperature polymer / blend (PHA, PBS, milk protein, legume protein, carrageenan).

[0029] If the barrier layer is an outer layer and a cold seal layer or heat seal layer (e.g., those shown in Figures 1(c), 2(a), (b), and (c)) is not applied, then a barrier layer with heat seal properties (such as those shown in Figures 1(b) and (d)) is employed or required.

[0030] The barrier layer 7 may be applied by extrusion coating, lamination, or by coating the substrate layer as a dispersion or solution in water or an organic solvent and then drying.

[0031] The barrier layer is applied to one or both sides of the substrate, preferably Polymer components selected from 51-99% by weight, preferably 90-99% by weight, more preferably 95-98% by weight, of polyhydroxyalkanoate polymers or copolymers, milk-derived or plant-derived proteins such as legumes, polylactic acid, polybutylene succinate or its copolymers, starch, chitosan, carrageenan, pectin, alginate, lipids, polyacrylic polymers, polyurethanes, cellulose or chemically modified cellulose, and mixtures thereof, as well as 51-99% by weight, preferably 90-99% by weight, more preferably 95-98% by weight, of polyhydroxyalkanoate polymers or copolymers, milk-derived or plant-derived proteins such as legumes, polylactic acid, polybutylene succinate or its copolymers, starch, chitosan, carrageenan, pectin, alginate, lipids, polyacrylic polymers, polyurethanes, cellulose or chemically modified cellulose, and mixtures thereof, and The material contains 49 to 1% by weight, preferably 1 to 10% by weight, more preferably 2 to 5% by weight, of a filler selected from layered double hydroxides, particularly hydrotalcite or hydrotalcite-like minerals, nanocellulose, silicates, clay, and mixtures thereof (the weight percentages are based on 100 parts by weight of the polymer component and the filler).

[0032] In another embodiment, the barrier coating layer is obtained by applying and drying a lacquer containing the polymer and the aforementioned filler or one or a blend of fillers in water or an organic solvent medium. A suitable aqueous dispersion typically contains 5 to 70% by weight, preferably 20 to 60% by weight, of solids (polymer and filler). Suitable organic solvents include ethanol or ethyl acetate containing 5 to 70% by weight, preferably 20 to 60% by weight, of solids (polymer and filler).

[0033] In one embodiment, the barrier layer may be obtained from lacquer and provided on both sides of the substrate (Figure 1(d)).

[0034] In another embodiment, the multilayer structure may include a barrier coating layer extruded or laminated onto a substrate and a heat-sealable barrier layer obtained from lacquer on the opposite side of the substrate (Figure 1(d)).

[0035] In another embodiment, the multilayer structure may be such that the barrier coating layer obtained from lacquer is placed on top of the barrier layer which is extruded or laminated onto the substrate layer, or, if the barrier layer is extruded or laminated on both sides of the substrate, the barrier coating layer obtained from lacquer can be placed on both extruded or laminated layers.

[0036] If the barrier layer is not heat-sealable, a heat-sealable layer 9 obtained from a heat-sealable lacquer may be applied as an outer layer (Figure 1(c)). The polymer for the heat-sealable lacquer is the same low-melting-point polymer as disclosed for the barrier layer, but this layer 9 does not contain fillers.

[0037] The polyhydroxyalkanoate (PHA) used in the barrier layer may be the same as that used for the substrate as described above.

[0038] The polybutylene succinate (PBS) copolymer used in the barrier layer may be the same as that used for the substrate as described above.

[0039] Plant-based proteins include proteins derived from legumes such as peas and lentils, or proteins derived from fungi.

[0040] Suitable polymer components for the barrier layer include polylactic acid, thermoplastic blends of starch and aliphatic polyesters, chitosan, carrageenan, and pectin.

[0041] The fillers used in the barrier layer of the present invention are selected from layered double hydroxides (LDHs), nanocellulose, natural or synthetic layered silicates, and mixtures thereof. Preferred LDHs include hydrotalcite and hydrotalcite-like minerals.

[0042] Preferred nanocellulose materials include cellulose nanofibers (CNF), nanocrystalline cellulose (CNC), or bacterial nanocellulose (BNC). The term nanocellulose also includes nanocellulose modified by esterification, amidation, etherification, etc.

[0043] Preferred layered silicates include montmorillonite, bentonite, hectorite, smectite, and mica. The fillers used typically have particle sizes with the following characteristics: One direction: 1~40μm Other direction: 1nm~2μm Aspect ratio: 1.20~20,000

[0044] The barrier layer typically contains 0.5-10 g / m². 2 Preferably 1-5 g / m 2 , comfortably 1-3 g / m 2 It is applied within the following weight range.

[0045] In a preferred embodiment of the present invention, the laminated or extruded coated barrier layer is heat-sealable, in which case the polymer components are preferably polyhydroxyalkanoates (as described above), polybutylene succinates, polybutylene adipate terephthalates, and polylactic acid, which are combined with fillers preferably selected from layered double hydroxides and nanocellulose.

[0046] Furthermore, in embodiments that enable obtaining a heat-sealable barrier layer as a surface layer of a multilayer material, the polymer component is selected from the group consisting of protein materials, preferably proteins derived from milk, fungi, peas, and gelatin.

[0047] The multilayer packaging material may further include one or more primer layers (not shown) applied to one or both sides of the substrate layer between the surface of the substrate layer and the barrier coating layer. The primer layers may be used to improve the spreading and adhesion of the subsequent coating.

[0048] Primers for the purposes of the present invention are selected from the group consisting of acrylic acid copolymers, polyesters, polyhydroxyalkanoates, natural and chemically modified starches, xylan and chemically modified xylans, polyvinylidene chloride, polyvinyl alcohol, ethylene vinyl alcohol, vinyl acetate, ethylene vinyl acetate, cellulose nitrate, silane, polyurethane, or combinations thereof.

[0049] If the multilayer packaging material of the present invention does not include a heat-sealable surface layer, the cold seal layer 11 (Figures 2(a), (b), and (c)) can be applied as a surface coating to a limited area of ​​the packaging material as needed.

[0050] The cold seal layer 11 is typically prepared from latex or a non-allergenic latex suspension. Alternatively, aqueous acrylic or synthetic latex systems may be used. Additives or pigments may be included in the cold seal layer (e.g., 0.1–5% by weight relative to the resin).

[0051] Typically, the multilayer structure includes a surface printing layer 13 applied using conventional printing inks, natural inks, and conventional printing techniques such as offset printing or gravure printing.

[0052] The printed layer may be further coated with a protective varnish. A protective varnish is applied to prevent damage to the ink or coating during the lifespan of the packaging. Damage can occur due to attacks by moisture or solvents, or due to mechanical stress or abrasion. The protective varnish is applied using the same technique as the printing ink.

[0053] Protective varnishes typically contain resin, additives / stabilizers / modifiers, and solvents. Suitable solvents include water, ethanol, and ethyl acetate. Resins can be selected from nitrocellulose or other modified celluloses, acrylic polymers, and polyurethanes.

[0054] In particular, in embodiments in which the multilayer structure includes a cold-sealable surface layer 11, a release coating layer 15 covering the printed layer can be applied to the surface of the multilayer structure opposite to the cold-sealable layer in order to provide release properties.

[0055] Release varnishes are applied to facilitate the unwinding of print reels and to prevent cold seals from adhering to other parts of the packaging structure. The release varnishes under consideration have the same components as protective varnishes but include additional slip agents or release agents. The slip agents or release agents can be selected from silicone-containing compounds, fatty acids or fatty acid esters, vegetable oils or other plant-derived oils, carnauba wax or other bio-based waxes, and paraffin waxes.

[0056] A preferred embodiment of the present invention includes a multilayer packaging material, wherein the barrier layer of the multilayer packaging material is heat-sealable. 50-70% by weight of PHA with a melting point of 60-170°C, 20-40% by weight of PBS, and 0.5 to 3% by weight of nanocellulose (preferably CNC) and 9.5% by weight or less of additives and / or fillers selected from the aforementioned additives and / or fillers other than nanocellulose (where the total weight percentage is 100%), or: 90% by weight of PHA, preferably PHBH, Dispersed CNC with 0.5-3% by weight, 7-9.5% by weight of non-CNC additives / fillers (where the total percentage is 100%) or: 90% by weight of PHA, preferably PHBH, 0.5 to 3% by weight of dispersed LDH, preferably hydrotalcite. 7-9.5% by weight of additives / fillers other than LDH (where the total percentage is 100%) Includes.

[0057] In a more preferred embodiment, the barrier layer is heat-sealable, laminated, or extruded coated, and the barrier layer is 50-60% by weight of PHA with a melting point of 60-170°C, 20-30% by weight of PBS, 0.5-10% by weight of dispersed layered double hydroxide, and 5-9.5% by weight of additives / fillers (excluding LDH) (Here, the sum of the percentages is 100%) Includes. [Examples]

[0058] Examples 1 to 6 relate to embodiments of composite co-extruded substrates that can be used to provide the packaging material of the present invention as a flexible film or a thermoformable sheet.

[0059] In Examples 1 to 6, the core layer and skin layer used to provide the flexible film preferably have a thickness of 12 to 45 μm (in total), more preferably about 20 μm, and the core layer and skin layer used to provide the thermoformable sheet generally have a thickness of 500 to 1500 μm.

[0060] (Example 1; Figure 3) Core layer 3: PHA (preferably PHBH) containing 0.5 to 10% by weight of clay (preferably hydrotalcite) dispersed in a polymer matrix. Skin layer 5: Both are PBS

[0061] (Example 2; Figure 4) Core layer 3: PBS containing 0.5–10% by weight of clay (preferably hydrotalcite) dispersed in a polymer matrix. Skin layer 5: Both are PHA (preferably PHBH).

[0062] (Example 3; Figure 5) Core layer 3: PHA (preferably PHBH) containing 0.5 to 3% by weight of nanocellulose (preferably CNC) dispersed in a polymer matrix. Skin layer 5: Both are PBS.

[0063] (Example 4; Figure 6) Core layer 3: PHA (preferably PHBH) containing 0.5 to 3% by weight of nanocellulose (preferably CNC) dispersed in a polymer matrix. Surface layer 5: Both are PHA (preferably PHBH).

[0064] (Example 5; Figure 7) Core layer 3: PBS containing 0.5-3% by weight of nanocellulose (preferably CNC) dispersed in a polymer matrix. Skin layer 5: Both are PHA (preferably PHBV).

[0065] (Example 6; Figure 8) Core layer 3: PBS containing 0.5 to 3% by weight of nanocellulose (preferably CNC) dispersed in a polymer matrix. Skin layer 5: Both are PBS.

[0066] The coextruded composite substrates shown in Examples 1 to 6 may be used according to the layouts of FIGS. 1 and 2.

[0067] Examples 9 to 11 relate to preferred embodiments of flexible films especially for flow pack and pouch packaging applications:

[0068] (Example 9) External printing layer: Preferably 1 g / m by weight 2 、 Coextruded composite layer according to Example 5 (FIG. 7) or Example 3 (FIG. 5), thickness: 20 μm, (Extrusion coated or laminated) barrier layer (weight: about 10 g / m 2 ) consisting of 50 to 60% by weight of heat-sealable PHA with a melting temperature of 60 to 170 °C, 20 to 30% by weight of PBS, 0.5 to 10% by weight of dispersed layered double hydroxide, and 5 to 9.5% by weight of conventional additives (the sum of the above percentages is 100%) Barrier layer containing Multilayer flexible film having a structure comprising or consisting of.

[0069] Oxygen barrier property measured at 23 °C and 40 to 50% RH: (about 300 to about 0.5 cc / m 2 ·24 h.

[0070] By adding a clay-based or metal oxide-based additional layer, the moisture barrier property can be further improved to a value of less than 20 g / m 2 ·24 h at 38 °C and 90% RH.

[0071] (Example 10) External printing layer: Preferably about 1 g / m by weight 2 、 Co-extruded composite layer according to Example 5 (Figure 7) or Example 3 (Figure 5), thickness: 20-40 μm (preferably 20 μm), (Extruded or laminated) barrier layer (Weight: approx. 10g / m²) 2 ) and Heat-sealable PHA with a melting point of 60-170°C and a concentration of 50-60% by weight. 20-30% by weight of PBS, 0.5-10% by weight of dispersed layered double hydroxide, and Conventional additives in amounts of 5-9.5% by weight (the sum of the above percentages is 100%) barrier layer A multilayer flexible film having a structure that includes or consists of The barrier layer is coated with a PBS film (15 μm thick) which is useful for preventing or reducing peeling of the barrier layer.

[0072] (Example 11) A multilayer flexible film having the structure shown in Figure 9. The barrier layer is made of PHA (thickness: 3-8 μm, weight: approximately 10 g / m²). 2 It consists of nanocellulose (preferably 0.5-3% by weight of CNC) or hydrotalcite (0.5-10% by weight) and is sandwiched between two PHA films (12 μm and 20 μm). The PHA layer opposite the printed layer is selected to have heat-seal properties.

[0073] Examples 12 and 13 relate to preferred embodiments of thermoformable sheets. (Example 12) An extruded coating or laminated barrier layer of a proteinaceous material (milk-derived protein) having a thickness of 10 μm, containing nanocellulose (preferably 0.5 to 3% by weight of CNC) or hydrotalcite (0.5 to 10% by weight), is sandwiched between two PHA sheets or co-extruded composite layers having a thickness of 250 to 500 μm.

[0074] (Example 13) An extruded coating or laminated barrier layer of a proteinaceous material (milk-derived protein) having a thickness of 10 μm, containing nanocellulose (preferably 0.5-3 wt% CNC) or hydrotalcite (0.5-10 wt%), is sandwiched between PBS films (10 μm thick) with a thickness of 10 μm. An extruded coating or laminated barrier layer having a thickness of 10 μm, containing (preferably CNC, 0.5-3 wt%) or hydrotalcite (0.5-10 wt%), is sandwiched between a PBS film (15 μm) and a composite co-extruded sheet having a thickness of 500-1500 μm and having one of the structures of Examples 1-6 (see Figure 10).

[0075] The multilayer structure of packaging materials includes the following additional layers: A wax coating layer that functions as a moisture barrier (for example, 5-15 g / m² obtained from an aqueous wax-based dispersion). 2 (wax layer), A hydrotalcite layer (for example, 4-5 g / m² of substantially pure hydrotalcite, preferably obtained from a 30-60 wt% hydrotalcite aqueous dispersion) provides improved barrier and mechanical properties. 2 layer), A nanocellulose (preferably CNC) layer is used to improve oxygen barrier properties and mechanical properties (for example, 1 to 5 g / m² of substantially pure CNC obtained from an aqueous dispersion containing 20 to 40% by weight solids). 2 layer. ) It is understood that it may include [Explanation of Symbols]

[0076] 1. Polymer substrate (single-layer film or sheet, or co-extruded composite film or sheet) 3. Interlayer of co-extruded composite film or sheet 5. Surface layer of co-extruded composite film or sheet 7… Barrier layer 9. Any layer obtained by applying heat-sealable lacquer. 11 … Any continuous or discontinuous cold-sealable layer 13 … Any continuous or discontinuous printing layer 15 … Any layer obtained from the stripped varnish

Claims

1. Polymer substrates containing or composed of polymer components, and A barrier coating layer formed on one or both sides of the substrate. Includes, The polymer component is selected from the group consisting of polyhydroxyalkanoate polymers or copolymers, polybutylene succinate or its copolymers, polylactic acid, polybutylene adipate terephthalate, and mixtures thereof. The barrier coating layer 51 to 99% by weight, preferably 90 to 99% by weight, more preferably 95 to 98% by weight, of polymer components selected from the group consisting of polyhydroxyalkanoate polymers or copolymers, milk or leguminous plant-derived proteins, polylactic acid, polybutylene succinate or its copolymers, starch, chitosan, carrageenan, pectin, alginate, lipids, polyacrylic polymers, polyurethanes, cellulose or chemically modified cellulose and mixtures thereof, and A filler selected from the group consisting of layered double hydroxides, nanocellulose, silicates, clay, and mixtures thereof, in an amount of 49 to 1% by weight, preferably 1 to 10% by weight, and more preferably 2 to 5% by weight. A multilayer packaging material containing (weight percent is based on 100 parts by weight of polymer components and fillers).

2. The multilayer packaging material according to claim 1, wherein the polyhydroxyalkanoate (PHA) for the substrate or barrier layer comprises a medium-chain PHA having 6 to 14 carbon atoms in the monomer unit, typically having a melting point of 50 to 170°C, preferably 100 to 160°C.

3. The multilayer packaging material according to claim 1 or 2, wherein the polyhydroxyalkanoate of the substrate or barrier coating is selected from the group consisting of poly(3-hydroxybutyrate) (3HB), poly(4-hydroxybutyrate) (4HB), poly(3-hydroxyvalerate) (3HV), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(hydroxybutyrate-co-hydroxyhexanoate), poly(3-hydroxy-co-4-hydroxybutyrate), copolymers thereof, and mixtures thereof.

4. In the aforementioned substrate, the polymer component consists of a polyhydroxyalkanoate polymer or copolymer, polybutylene succinate, or a blend of polyhydroxyalkanoate and polybutylene succinate. The aforementioned blend contains 50 to 70% by weight of polyhydroxyalkanoate and 30 to 50% by weight of polybutylene succinate, based on 100 parts by weight of the polymer component. The aforementioned substrate further contains a filler in an amount of 10% by weight or less, based on 100 parts by weight of the polymer component. The multilayer packaging material according to claim 1, 2, or 3, wherein the filler is selected from the group consisting of layered double hydroxide (LDH), clay, nanocellulose, starch, and mixtures thereof.

5. The multilayer packaging material according to claim 4, wherein the base material further comprises 0.5 to 3% by weight of cellulose nanocrystals (CNC) per 100 parts by weight of the polymer component.

6. The multilayer packaging material according to claim 4, wherein the substrate each contains 0.5 to 10% by weight of dispersed layered double hydroxide (LDH) and 7 to 9.5% by weight of the filler other than LDH, based on 100 parts by weight of the polymer component.

7. The substrate is a composite co-extruded film or sheet comprising a core layer and a skin layer thinner than the core layer, formed on one or both sides of the core layer. The multilayer packaging material according to any one of claims 1 to 6, wherein the core layer is a polymer film formed from a polyhydroxyalkanoate or polybutylene succinate, or a mixture thereof, and comprises a filler dispersed in a polymer matrix, the filler being selected from layered double hydroxides and preferably contained in an amount of 0.5 to 10% by weight relative to the polymer matrix, and cellulose nanocrystals, preferably contained in an amount of 0.5 to 3% by weight relative to the polymer matrix, and the skin layer is a co-extruded coating comprising polymer components selected from polyhydroxyalkanoate, polybutylene succinate, and mixtures thereof.

8. The multilayer packaging material according to any one of claims 1 to 7, wherein the barrier coating is a heat-sealable layer of the packaging material, and the polymer component of the barrier coating consists of a polymer selected from polyhydroxyalkanoate, polybutylene succinate, milk protein, vegetable protein, carrageenan, or a mixture thereof, and the heat-seal temperature is 60 to 170°C.

9. The multilayer packaging material according to any one of claims 1 to 8, wherein the barrier layer is a heat-sealable surface layer of the packaging material, the polymer component of the barrier layer is a polyhydroxyalkanoate or a blend of polyhydroxyalkanoates, and the heat-seal temperature is 60 to 170°C.

10. The multilayer packaging material according to claim 1, wherein the barrier layer is obtained by applying and drying a lacquer containing the polymer component and filler in water or a solvent medium.

11. A multilayer packaging material according to any one of claims 1 to 7, further comprising a heat-sealable surface layer obtained from a lacquer that contains a heat-sealable polymer component and does not contain fillers.

12. The multilayer packaging material according to any one of claims 1 to 11, further comprising a surface protective coating on the side opposite to the barrier layer relative to the core, obtained from a varnish containing a liquid medium selected from water, ethanol, and ethyl acetate, and a polymer selected from nitrocellulose or chemically modified cellulose, polyacrylic polymers, and polyurethanes.

13. A multilayer packaging material according to any one of claims 1 to 12, further comprising a surface release coating containing a slip agent or release agent selected from the group consisting of silicone-containing compounds, fatty acids or fatty acid esters, vegetable oils, carnauba wax, and paraffin wax.

14. The multilayer packaging material according to any one of claims 1 to 13, further comprising a primer layer applied to one or both sides of the substrate between the surface of the substrate layer and the barrier coating layer.

15. The packaging material according to any one of claims 1 to 14, further comprising an ink-printed layer.

16. The multilayer packaging material according to claim 1, comprising a cold-sealable layer formed from a latex suspension as a surface layer, and optionally comprising additives or pigments.

17. A composite co-extruded film or sheet comprising a core layer and a skin layer thinner than the core layer formed on one or both sides of the core layer, wherein the core layer is a polymer film comprising polyhydroxyalkanoate or polybutylene succinate and mixtures thereof containing a filler dispersed in a polymer matrix, the filler being selected from layered double hydroxides and preferably contained in an amount of 0.5 to 10% by weight relative to the polymer matrix, and cellulose nanocrystals, preferably contained in an amount of 0.5 to 3% by weight relative to the polymer matrix, and the skin layer is a co-extruded coating comprising polymer components selected from polyhydroxyalkanoate, polybutylene succinate and mixtures thereof.

18. A composite co-extruded sheet according to claim 17, which is thermoformable and has a thickness of 500 to 1500 μm.

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