Biodegradable film for tobacco packaging

Abstract

Provided is a biodegradable film for packaging tobacco, comprising a first film layer applied with one side facing a tobacco product, a third film layer applied with one side exposed to the outside, and a second film layer positioned between the first film layer and the third film layer. In the biodegradable film, the first film layer, the second film layer, and the third film layer each have a different composition, and at least one layer among the first film layer, the second film layer, and the third film layer contains a biodegradable material. The biodegradable film has a biodegradation rate of 90% or more after 60 days, and a heat shrinkage rate of 4.0% or more.

Description

Technical Field

[0001] The present invention relates to a biodegradable film for tobacco packaging.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0180288 filed on December 16, 2021, and Korean Patent Application No. 10-2022-0175881 filed on December 15, 2022, and incorporates all the contents disclosed in the corresponding Korean patent applications as part of this specification.

Background Art

[0003] Synthetic plastics are widely used as packaging materials that require excellent physical properties, low cost, light weight, etc. Examples of such synthetic plastics include polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc. Despite their excellent physical properties, many harmful substances are generated during manufacturing or incineration, and due to their chemical and biological stability, they are hardly decomposed and accumulate, causing environmental pollution problems. Recently, with the emergence of environmental issues, interest in environmentally friendly biodegradable materials that can replace the synthetic plastics has been increasing.

[0004] Currently, the main material used for tobacco packaging is a paper packaging material in the form of an open box as a container for holding tobacco products, and a film is used outside the paper packaging material for sealing and packaging to maintain the quality of the products against moisture and oxidation reduction. Currently, OPP film is mainly used for the commercially available external sealing packaging material. The OPP film is a petroleum-based plastic material and is mostly discharged as general waste because it is not a target for separate discharge. The OPP film also has an environmental pollution problem in that it has low biodegradability, and research on alternative materials with high biodegradability while maintaining functionality like the OPP film is actively being conducted in the relevant technical field.

[0005] The inventor of the present invention recognized the technical problems with the packaging material for externally sealing tobacco products described above, and after continuous research on materials that can replace OPP films, completed the present invention.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In a biodegradable film for tobacco packaging, in order to replace the existing OPP film with a biodegradable material, it is intended to provide a biodegradable film that can complement the functionality other than biodegradability of the biodegradable material and improve workability as well as heat adhesiveness and barrier properties.

Means for Solving the Problems

[0008] According to a first aspect of the present invention, the present invention provides a biodegradable film for tobacco packaging, including a first film layer applied so that one side faces a tobacco product, a third film layer applied so that one side is exposed to the outside, and a second film layer located between the first film layer and the third film layer.

[0009] According to a specific example of the present invention, the first film layer, the second film layer, and the third film layer are each composed of a different composition, and one or more of the first film layer, the second film layer, and the third film layer contain a biodegradable substance.

[0010] According to a specific example of the present invention, the biodegradable film has a biodegradation rate of 90% or more after 60 days and a heat shrinkage rate of 4.0% or more.

[0011] According to a specific example of the present invention, the biodegradable film has a difference in thermal shrinkage rate between the longitudinal direction and the width direction of less than 1%.

[0012] According to a specific example of the present invention, the biodegradable film has an oxygen permeability of 1000 cc / (m 2 ·day·atm) or less.

[0013] According to a specific example of the present invention, the biodegradable film has a moisture permeability of 50 g / (m 2 ·day·atm) or less.

[0014] According to a specific example of the present invention, the biodegradable film has a gas density of 50 ml / sec or less.

[0015] According to a specific example of the present invention, the biodegradable film has a haze of 6.0% or less.

[0016] According to a specific example of the present invention, the biodegradable substance is selected from the group consisting of polylactic acid, polyhydroxyalkanoic acid, starch, cellulose-based substances, polyvinyl alcohol, polycaprolactone, polybutylene adipate terephthalate, polyethylene succinate, polybutylene succinate, polyglycolic acid, and combinations thereof.

[0017] According to a specific example of the present invention, the layer containing the most biodegradable substance among the first film layer, the second film layer, and the third film layer is the second film layer.

[0018] According to a specific example of the present invention, the second film layer is 80% by volume or more of the biodegradable film.

[0019] According to a specific example of the present invention, the first film layer or the third film layer contains a biodegradable substance having physical properties different from those of the second film layer.

[0020] According to a specific example of the present invention, the first film layer or the third film layer contains a vinyl-based compound, an ethylene-vinyl alcohol copolymer, an acrylic-based compound, a sealant compound, an OP coating-based compound, a urethane-based compound, a silicone-based compound, an epoxy-based compound, nanocellulose, an inorganic substance, or a combination thereof.

[0021] According to a specific example of the present invention, the second film layer contains semi-crystalline polylactic acid, and the first film layer or the third film layer contains amorphous polylactic acid.

[0022] According to a specific example of the present invention, the first film layer or the third film layer contains polyvinyl alcohol, polyvinyl chloride, or polyvinylidene chloride.

[0023] According to a specific example of the present invention, the second film layer has a thickness of 5 μm to 30 μm, and the first film layer and the third film layer each have a thickness of 0.1 μm to 10 μm.

Advantages of the Invention

[0024] The biodegradable film according to a specific example of the present invention is a three-layer biodegradable film including a film layer such as a heat-sealing layer or a barrier coating layer centered on a biodegradable base material layer containing a biodegradable substance, and has excellent functionality in terms of biodegradation rate, heat shrinkage rate, oxygen permeability, moisture permeability, airtightness, haze, etc., and can replace the existing OPP film for tobacco packaging.

Brief Description of the Drawings

[0025]

Figure 1

Embodiments for Carrying Out the Invention

[0026] The following will be described in detail through exemplary drawings. When assigning reference numerals to the components of each drawing, it should be noted that for the same components, as much as possible, the same numerals are used even if they are shown on other drawings. Also, when explaining a specific example, if it is determined that a detailed explanation of such a known configuration or function will interfere with the understanding of the specific example, the detailed explanation will be omitted.

[0027] Also, when explaining the components of a specific example, terms such as first, second, A, B, (a), (b), etc. can be used. Such terms are only for distinguishing the components from other components, and the essence, order, or procedure of the corresponding components are not limited by such terms. When a certain component is described as being "connected", "coupled", or "joined" to another component, it should be understood that the component can be directly connected or joined to the other component, but other components can also be "connected", "coupled", or "joined" between the components.

[0028] Components included in any one of the specific examples and components having a common function will be described using the same name in other specific examples. Unless otherwise stated, the explanations described in any one of the specific examples can also be applied to other embodiments, and specific explanations within the overlapping range will be omitted.

[0029] The present invention relates to a biodegradable film for tobacco packaging, and more specifically, to a biodegradable film for sealing and packaging the outside of a paper packaging material directly containing a tobacco product. FIG. 1 provides a drawing showing a schematic configuration of a biodegradable film for tobacco packaging according to a specific example of the present invention. As shown in FIG. 1, the biodegradable film according to a specific example of the present invention includes a first film layer 10, a second film layer 20, and a third film layer 30. Since the biodegradable film is divided into a surface facing the tobacco product and a surface exposed to the outside when packaging the tobacco product, each film layer is divided and shown as the first film layer 10, the second film layer 20, the third film layer 30, etc. One side of the first film layer 10 faces the tobacco product when packaging the tobacco product. Here, the tobacco product can also mean a state packaged with a paper packaging material or the like. One side of the third film layer 30 is exposed to the outside when packaging the tobacco product. The second film layer 20 is located between the first film layer 10 and the third film layer 30. One or more additional film layers can be applied between the first film layer 10 and the third film layer 30 as needed in addition to the second film layer 20.

[0030] The biodegradable film according to a specific example of the present invention has excellent functionality so that it can replace the existing OPP film. According to a specific example of the present invention, the biodegradable film has a biodegradation rate of 90% or more after 60 days. The biodegradation rate was measured by applying the ISO 14855-1 soil biodegradation degree measurement test standard and measuring the amount of carbon dioxide generated by biodegradating a film specimen under controlled composting and aerobic conditions. Generally, when it is decomposed by 90% or more with respect to a reference substance (cellulose), it is recognized as a biodegradable material. Although the biodegradable film is a film with a multi-layer structure, it can show a high biodegradation rate even in a short period of 60 days.

[0031] The biodegradable film according to a specific example of the present invention has excellent barrier properties so that while having high biodegradability, the quality of the internal tobacco products does not deteriorate. Generally, since biodegradable materials have biodegradability above a certain level, they are often vulnerable to the external environment such as moisture and air. Therefore, in order to manufacture a biodegradable film for tobacco packaging using a biodegradable material, a functional film layer capable of blocking the external environment such as moisture and air is required, and such a functional film layer is also included in other layers other than the film layer containing the biodegradable material in the multilayer biodegradable film according to a specific example of the present invention.

[0032] According to a specific example of the present invention, the biodegradable film has an oxygen permeability of 1000 cc / (m 2 ·day·atm) or less. Specifically, the oxygen permeability is 1000 cc / (m 2 ·day·atm) or less, 900 cc / (m 2 ·day·atm) or less, 800 cc / (m 2 ·day·atm) or less, 700 cc / (m 2 ·day·atm) or less, 600 cc / (m 2 ·day·atm) or less, 500 cc / (m 2 ·day·atm) or less, 400 cc / (m 2 ·day·atm) or less, 300 cc / (m 2 ·day·atm) or less, 200 cc / (m 2 ·day·atm) or less, 100 cc / (m 2 ·day·atm) or less, 50 cc / (m 2 ·day·atm) or less may also be acceptable. The oxygen permeability may be a value measured at 23°C and 0 RH% by the ASTM D 3985 (Method M, Pressure Method) method. For example, it can be measured using a measuring device such as a Gas Transmission Rate Tester (OX-TRAN 702 product manufactured by Mocon, USA).

[0033] According to a specific example of the present invention, the biodegradable film has a moisture permeability of 50 g / (m 2·day·atm) or less. Specifically, the moisture permeability is 50 g / (m 2 ·day·atm) or less, 45 g / (m 2 ·day·atm) or less, 40 g / (m 2 ·day·atm) or less, 35 g / (m 2 ·day·atm) or less, 30 g / (m 2 ·day·atm) or less, 25 g / (m 2 ·day·atm) or less, 20 g / (m 2 ·day·atm) or less, 15 g / (m 2 ·day·atm) or less, 10 g / (m 2 ·day·atm) or less may be sufficient. The moisture permeability may be a value measured at 38°C and 100% RH. For example, it can be measured using a measuring device such as a moisture permeability measuring device (PERMATRAN-W700 product manufactured by MOCON, USA).

[0034] According to one specific example of the present invention, the biodegradable film has an air density of 50 ml / sec or less. Specifically, the air density may be 50 ml / sec or less, 45 ml / sec or less, 40 ml / sec or less, 35 ml / sec or less, 30 ml / sec or less, 25 ml / sec or less, 20 ml / sec or less, 15 ml / sec or less, 10 ml / sec or less. The air density was measured using a device for measuring the air leakage of an OPP film for a cigarette box. The relevant air density is to measure the sealed state and air leakage state of the film using the air pressure. This can be measured using a measuring device such as an air density measuring machine (KARDIEN ALT-2 product manufactured by KADIEN, Korea).

[0035] A machine for wrapping a film around products such as cigarette boxes is a high-speed packaging machine capable of producing approximately 500 boxes per minute. The film is generally supplied in the form of a long roll and is cut to the required length for wrapping the products. During such a series of processes, the film must maintain the functionality related to biodegradability and barrier properties as described above, and also maintain excellent workability or productivity such as reducing the defective rate of packaging even within a high-speed packaging machine. In relation to this, heat adhesiveness is required so that the film to be applied can adhere well to the product, or heat shrinkability is required so that the film adheres well to the outer surface of the product without a bumpy surface after the packaging operation. Also, as described above, in order for a large number of products to be manufactured without defects in a continuous packaging process that proceeds at high speed, the coefficient of friction of the film surface is important. The biodegradable film according to a specific example of the present invention has high processability without defects in products even in a high-speed packaging machine for wrapping products such as cigarette boxes.

[0036] In the workability or processability of products, heat shrinkability can also be an important factor. By adding a coating layer to ensure functionality in a film base fabric made of a biodegradable material, the heat shrinkability can be reduced. After wrapping products such as cigarette boxes, if the film is adhered to the surface of the box, not only is the transfer easy, but the bumpy surface on the outer surface can be reduced, improving the beauty of the packaging appearance. Therefore, in order to increase the adhesion strength of the film after packaging, heat shrinkability above a certain level is required in the characteristics of the biodegradable film. According to a specific example of the present invention, the biodegradable film has a heat shrinkage rate of 4.0% or more, specifically 4.5% or more, and more specifically 5.0% or more. The heat shrinkage rate shall be applied mutatis mutandis to KS M ISO 17555. Specifically, a specimen with a width of about 20 mm and a length of about 150 mm is prepared (the MD and TD directions are the same), a reference point is marked at a distance of about 100 mm from the center, and it is placed in a hot air oven maintained at a temperature of 120°C. After heat treatment for 15 minutes, the length is measured and calculated by the following formula (Equation 1).

[0037] [Equation 1] Heat shrinkage rate (%) = (L i −L t) / L i ×100

[0038] In the formula (number 1), L i means the distance between reference points before heat treatment, and L t means the distance between reference points after heat treatment. The above length is the value selected as the lower value among the longitudinal direction or the machine direction (Machine Direction, MD direction) during material supply and the width direction or the machine perpendicular direction (Cross Direction, CD direction) during material supply, considering all of them. Since the lower value of the thermal shrinkage rates in the longitudinal and width directions is considered, the biodegradable film according to a specific example of the present invention can ensure a thermal shrinkage rate equal to or higher than the above numerical value in all directions. According to a specific example of the present invention, the difference in the thermal shrinkage rates in the longitudinal and width directions of the biodegradable film is less than 1%. The difference in the thermal shrinkage rate is calculated based on the larger value among the thermal shrinkage rates in the longitudinal and width directions. Specifically, the difference in the thermal shrinkage rate may be less than 1%, less than 0.9%, less than 0.8%, less than 0.7%, less than 0.6%, or less than 0.5%.

[0039] When functional properties such as the above-mentioned barrier property, heat adhesiveness, and coefficient of kinetic friction are imparted to the biodegradable material, the transparency of the film may be significantly reduced. Considering that information about tobacco products is mainly displayed on cigarette boxes, etc., the higher the transparency of the biodegradable film used as a packaging material for covering such cigarette boxes, etc., the greater its usability. According to a specific example of the present invention, the haze of the biodegradable film is 6.0% or less, specifically 5.5% or less, and more specifically 5.0% or less. The haze was measured with Haze gard-2 of Toyoseiki Co., Ltd. The biodegradable film according to a specific example of the present invention has a low haze value and can ensure a transparency of a certain level or higher, and has excellent adhesiveness to cigarette boxes and high visibility for the internal packaging target.

[0040] The biodegradable film according to a specific example of the present invention having the above-described functionality includes a first film layer, a second film layer, and a third film layer. The first film layer, the second film layer, and the third film layer are each separate layers, and are not only spatially separated as described above, but are also separated by the constituent components forming the film layer or by this composition. According to a specific example of the present invention, the first film layer, the second film layer, and the third film layer are each composed of different compositions, and one or more of the first film layer, the second film layer, and the third film layer contain biodegradable substances. The film layer containing the most of the biodegradable substances can basically become a support film layer, and other film layers can be introduced by coating around the corresponding film layer. Therefore, in this specification, the film layer containing the most of the biodegradable substances is also expressed as a biodegradable base material layer.

[0041] The biodegradable material can be a material with a high biodegradation rate while having durability above a certain level during film formation, and broadly, biodegradable biomass materials, biodegradable plastic materials, etc. can be used. According to one specific example of the present invention, the biodegradable material is selected from the group consisting of polylactic acid (PLA), polyhydroxyalkanoate (PHA), starch, cellulose-based substances, polyvinyl alcohol (PVA), polycaprolactone (PCL), polybutylene adipate terephthalate (PBAT), polyethylene succinate (PES), polybutylene succinate (PBS), polyglycolic acid (PGA), and combinations thereof. Here, the cellulose-based substance may be cellulose, a cellulose derivative, or regenerated cellulose. According to one specific example of the present invention, the support film layer or the biodegradable base material layer can contain 70% by weight or more, specifically 80% by weight or more, and more specifically 90% by weight or more of the biodegradable material based on the total weight of the layer.

[0042] According to one specific example of the present invention, the other coating layers except the support film layer or the biodegradable base material layer may contain biodegradable substances with other properties or add further functionality, and thus contain polyvinyl compounds, ethylene vinyl alcohol copolymers (EVOH), acrylic compounds, sealant compounds, OP coating compounds, urethane compounds, silicone compounds, epoxy compounds, nano-cellulose, inorganic compounds, or a combination thereof. These substances compensate for the insufficient functionality of the biodegradable base material layer.

[0043] The biodegradable substances introduced into the coating layer can have physical properties different from those of the support film layer or the biodegradable base material layer. According to one specific example of the present invention, the support film layer or the biodegradable base material layer contains semi-crystalline biodegradable polymers (for example, semi-crystalline polylactic acid), and the coating layer contains amorphous biodegradable polymers (for example, amorphous polylactic acid). Here, "amorphous" means that there is no regularity in the atomic arrangement among the atoms constituting the polymer substance, and "semi-crystalline" means that there is regularity in the atomic arrangement among some of the atoms constituting the polymer substance. Due to the characteristics of the polymer substance, biodegradable polymers can be semi-crystalline rather than amorphous in that it is difficult to have 100% crystallinity.

[0044] The above-mentioned substance can be functionally classified into a thermal adhesive layer and a barrier coating layer. The biodegradable film according to a specific example of the present invention simultaneously includes a thermal adhesive layer and a barrier coating layer together with a biodegradable base material layer. The biodegradable base material layer, the thermal adhesive layer, and the barrier coating layer can be arranged so as not to overlap in the first film layer, the second film layer, and the third film layer, respectively. Specifically, the second film layer can be the biodegradable base material layer, and the first film layer or the third film layer can be the thermal adhesive layer or the barrier coating layer. More specifically, the first film layer can be the thermal adhesive layer, the second film layer can be the biodegradable base material layer, and the third film layer can be the barrier coating layer. According to a specific example of the present invention, the thermal adhesive layer or the barrier coating layer can also contain a biodegradable substance, but it is not contained in a larger amount than the biodegradable base material layer.

[0045] The thermal adhesive layer contains a vinyl-based compound, an ethylene vinyl alcohol copolymer, an acrylic-based compound, a sealant-based compound, an OP coating-based compound, or a combination thereof. The barrier coating layer contains a vinyl-based compound, an ethylene vinyl alcohol copolymer, an acrylic-based compound, a urethane-based compound, a silicone-based compound, an epoxy-based compound, nanocellulose, an inorganic substance, or a combination thereof. When the materials of the thermal adhesive layer or the barrier coating layer are used in combination, they can be used by mixing them in one layer, or they can be separated into two or more layers and configured with different compositions for each layer. For example, when one layer of the barrier coating layer is formed by vapor deposition of an inorganic substance, a further barrier coating layer can be formed through the remaining components on the inorganic substance layer. The compounds contained in the thermal adhesive layer or the barrier coating layer are not particularly limited as long as they are substances generally used in the relevant technical field. The inorganic substance is, for example, Al 2 O 3 , SiO 2 , ZnO, ZrO 2 , BaTiO 3 , TiO 2 , Ta 2 O 5 , Ti 3 O 5, ITO, IZO, ATO, ZnO-Al, Nb 2 O 3 , SnO, MgO, etc. can be used, and there is no particular limitation as long as it is a substance generally used in the relevant technical field.

[0046] The polyvinyl-based compound includes a compound in which a hydroxyl group or a halogen group is substituted in the polyvinyl-based compound. Examples of the polyvinyl-based compound include compounds such as polyvinyl alcohol, polyvinyl chloride, and polyvinylidene chloride.

[0047] The acrylic-based compound can be an acrylic-based resin, etc., and there is no particular limitation as long as it is a substance generally used in the relevant technical field. The acrylic-based resin can be a water-dispersed emulsion-type acrylic-based resin, and an acrylic-based resin containing at least one functional group selected from the group consisting of a hydroxy group, a carboxyl group, an N-methylol group, an alkoxymethylol group, an acrylate group, and an acryloyl group can be used. For example, the acrylic-based resin can be obtained by polymerizing a (meth)acrylic-based monomer alone or copolymerizing a (meth)acrylic-based monomer and one or more copolymerizable monomers copolymerizable therewith.

[0048] The (meth)acrylic monomer includes, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, allyl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, etc. These can be used alone or in combination of two or more.

[0049] The copolymerizable monomer includes, for example, carboxyl group-containing ethylenically unsaturated monomers such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid; vinyl monomers such as acrylamide, acrylonitrile, vinyl acetate, ethylene, propylene, isobutylene, butadiene, isoprene, chloroprene; epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, allyl glycidyl ether, 3,4-epoxycyclohexylmethyl (meth)acrylate; and hydroxyl group-containing ethylenically unsaturated monomers such as hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate. These can be used alone or in combination of two or more. According to one specific example of the present invention, carboxyl group-containing ethylenically unsaturated monomers such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid can be used as the copolymerizable monomer.

[0050] The above-described compounds contained in the heat-sealing layer or the barrier coating layer can be contained in an appropriate amount in order for each film layer to obtain the intended functionality. According to a specific example of the present invention, 20% to 70% by weight of the above-described components can be contained in the film layer containing the same.

[0051] The biodegradable film can be adjusted to an appropriate thickness for use in tobacco packaging while ensuring the above-described functionality. According to a specific example of the present invention, the biodegradable film has a thickness of 10 μm to 50 μm. Specifically, the thickness of the biodegradable film may be 10 μm or more, 11 μm or more, 12 μm or more, 13 μm or more, 14 μm or more, 15 μm or more, and 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less. The thickness of each film layer can be adjusted as follows by the biodegradable base layer, the heat-sealing layer, or the barrier coating layer. According to a specific example of the present invention, the biodegradable base layer has a thickness of 5 μm to 30 μm, 10 μm to 30 μm, 15 μm to 25 μm, and the other coating layers excluding the biodegradable base layer have a thickness of 0.1 μm to 10 μm, 0.3 μm to 5 μm, 0.5 μm to 2 μm.

[0052] According to a specific example of the present invention, 80% by volume or more, 85% by volume or more, 90% by volume or more of the support film layer or the biodegradable base layer can be contained in the biodegradable film. The area of each film layer may be substantially the same, and the volume ratio can be proportional to the ratio of the thickness of each film layer. When there are two other coating layers excluding the biodegradable base layer, each of the remaining coating layers can account for 10% by volume or less, 9% by volume or less, 8% by volume or less, 7% by volume or less, 6% by volume or less, 5% by volume or less in the biodegradable film.

[0053] According to a specific example of the present invention, the support film layer or the biodegradable base material layer is a second film layer. By using the second film layer located in the center of the biodegradable film as the biodegradable base material layer, the proportion of the biodegradable base material layer can be increased. According to a specific example of the present invention, the second film layer is 80% by volume or more of the biodegradable film. According to a specific example of the present invention, the first film layer or the third film layer contains a biodegradable substance having physical properties different from those of the second film layer. According to a specific example of the present invention, the first film layer or the third film layer contains a vinyl-based compound, an ethylene vinyl alcohol copolymer, an acrylic-based compound, a sealant compound, an OP coating-based compound, a urethane-based compound, a silicone-based compound, an epoxy-based compound, nanocellulose, an inorganic substance, or a combination thereof. According to a specific example of the present invention, the second film layer contains semi-crystalline polylactic acid, and the first film layer or the third film layer contains amorphous polylactic acid. According to a specific example of the present invention, the first film layer or the third film layer contains polyvinyl alcohol, polyvinyl chloride, or polyvinylidene chloride. According to a specific example of the present invention, the first film layer contains amorphous polylactic acid, and the third film layer contains polyvinyl alcohol, polyvinyl chloride, or polyvinylidene chloride. In a specific example of the present invention, the second film layer has a thickness of 5 μm to 30 μm, and the first film layer and the third film layer each have a thickness of 0.1 μm to 10 μm.

[0054] Hereinafter, the configuration of the present invention and the effects thereof will be described in more detail through examples and comparative examples. However, these examples are for more specifically explaining the present invention, and the scope of the present invention is not limited to these examples.

Examples

[0055] [Example 1] A semi-crystalline polylactic acid film (product TE90C of SKC) with a thickness of about 21 μm was prepared for the second film layer. In order to form a first film layer on the second film layer that is applied so that one side faces the tobacco product, an amorphous polylactic acid (product of SKC) with a thickness of about 1 μm was coated on the second film layer. In order to form a third film layer on the second film layer that is applied so that one side is exposed to the outside, polyvinylidene chloride (product of Yulchon) with a thickness of about 1 μm was coated on the other side of the second film layer that was not coated with the first film layer. The manufactured three-layer biodegradable film was used for a tobacco packaging machine to package tobacco products by the heat seal method. The biodegradable film contained a polylactic acid film with a high biodegradation rate of about 90% by volume or more to ensure its functionality as a biodegradable film.

[0056] [Comparative Example 1] A two-layer biodegradable film was manufactured in the same manner as in Example 1, except that the first film layer was not coated on the second film layer, and about 1 μm thick amorphous polylactic acid (product of SKC) was coated on the third film layer.

[0057] [Comparative Example 2] A three-layer biodegradable film was manufactured in the same manner as in Example 1, except that about 1 μm thick OP coating system compound (product ECOBY-OPP of Yulchon) was coated on the third film layer.

[0058] [Experimental Example] In order to evaluate whether the biodegradable films manufactured in Example 1 and Comparative Examples 1 and 2 have physical properties suitable for tobacco packaging, the heat shrinkage rate, oxygen permeability, moisture permeability, airtightness, and haze were measured and are shown in Table 1 below. The method for measuring each physical property basically follows the general methods in the relevant technical field, and specifically, it was measured by the method specified in the above-mentioned content.

[0059]

Table 1

[0060] *The heat shrinkage rate selects a low value among the heat shrinkage rates in the longitudinal direction and the width direction, and the difference in the heat shrinkage rate is the value obtained by subtracting the low value from the high value among the heat shrinkage rates in the longitudinal direction and the width direction.

[0061] According to Table 1 above, even if the biodegradable film is charged at about 90% by volume or more in the second film layer, the tobacco product can be packaged by introducing the first film layer and the third film layer with appropriate materials, and it can be confirmed that a biodegradable film having suitable physical properties can be manufactured as in Example 1. In addition, a biodegradable film having such physical properties is difficult to achieve without either the first film layer or the third film layer as in Comparative Example 1, and it is also difficult to achieve even if a coating substance well known in the coating field is coated as in Comparative Example 2.

[0062] As described above, the specific examples have been described by way of limited specific examples and drawings, but those having ordinary knowledge in the relevant technical field can make various modifications and variations from the above description. For example, whether the described technology is carried out in a procedure different from the described method, and / or whether the components such as the described system, structure, device, circuit, etc. are combined or combined in a form different from the described method, or are opposed or replaced by other components or equivalents, appropriate results can be achieved.

Explanation of Reference Numerals

[0063] 100: Biodegradable film for tobacco packaging 10: First film layer 20: Second film layer 30: Third film layer

Claims

1. As a biodegradable film for cigarette packaging, a first film layer applied so that one side faces the cigarette product, a third film layer applied so that one side is exposed to the outside, and a second film layer positioned between the first film layer and the third film layer, wherein the first film layer, the second film layer, and the third film layer are each composed of a different composition, and one or more of the first film layer, the second film layer, and the third film layer contain a biodegradable polymer, the biodegradable film for cigarette packaging has a biodegradation rate of 90% or more after 60 days, a heat shrinkage rate of 4.0% or more, a haze of 6.0% or less, and the second film layer is 90% by volume or more of the biodegradable film for cigarette packaging.

2. The biodegradable film for cigarette packaging according to Claim 1, wherein the difference in heat shrinkage rate between the longitudinal direction and the width direction is less than 1%.

3. The oxygen permeability is 1000 cc / (m ２ ·day·atm) or less, the biodegradable film for tobacco packaging according to claim 1 or 2.

4. The moisture permeability is 50 g / (m ２ ·day·atm) or less, the biodegradable film for tobacco packaging according to claim 1 or 2.

5. The biodegradable film for cigarette packaging according to Claim 1 or 2, having an air permeability of 50 ml / sec or less.

6. The biodegradable film for cigarette packaging according to Claim 1 or 2, wherein the biodegradable polymer is selected from the group consisting of polylactic acid, polyhydroxyalkanoic acid, starch, cellulose-based substances, polyvinyl alcohol, polycaprolactone, polybutylene adipate terephthalate, polyethylene succinate, polybutylene succinate, polyglycolic acid, and combinations thereof.

7. The biodegradable film for cigarette packaging according to Claim 1 or 2, wherein the layer containing the most biodegradable substance among the first film layer, the second film layer, and the third film layer is the second film layer.

8. The biodegradable film for cigarette packaging according to Claim 7, wherein the first film layer or the third film layer contains a biodegradable substance having physical properties different from those of the second film layer.

9. The biodegradable film for cigarette packaging according to Claim 7, wherein the first film layer or the third film layer contains a polyvinyl-based compound, an ethylene vinyl alcohol copolymer, an acrylic-based compound, a sealant compound, a urethane-based compound, a silicone-based compound, an epoxy-based compound, nanocellulose, an inorganic substance, or a combination thereof.

10. The second film layer contains semi-crystalline polylactic acid, The biodegradable film for tobacco packaging according to claim 7, wherein the first film layer or the third film layer contains amorphous polylactic acid.

11. The biodegradable film for tobacco packaging according to claim 9, wherein the first film layer or the third film layer contains polyvinyl alcohol, polyvinyl chloride or polyvinylidene chloride.

12. The second film layer has a thickness of 5 μm to 30 μm, The biodegradable film for tobacco packaging according to claim 7, wherein the first film layer and the third film layer each have a thickness of 0.1 μm to 10 μm.

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