KR102229068B1 - wrap film of multi layer - Google Patents

Abstract

The present invention relates to a multi-layer antibacterial film for packaging and, more specifically, to an antibacterial film of a multi-layer structure used for packaging various articles such as foods and having antibacterial properties. The multi-layer antibacterial film for packaging of the present invention comprises: an inner layer having thickness of 5 to 15 μm formed by mixing linear low-density polyethylene (LLDPE) and nano-copper particles; a middle layer formed on the inner layer and with thickness of 20 to 40 μm formed of the LLDPE; and an outer layer formed on the middle layer and with 10 to 20 μm in thickness formed by mixing the LLDPE and the nano-copper particles, wherein the inner layer is formed by further mixing a corn extract.

Description

Wrap film of multi layer}

The present invention relates to a multilayer antibacterial film for packaging, and more particularly, to an antimicrobial film having a multilayer structure having antibacterial properties and used for packaging various articles such as food.

With the development of the industry, the demand for films using synthetic resins is increasing rapidly, and they are used in many parts of daily life.

Currently, films used for packaging are widely used in general homes, restaurants, and distribution packaging of various fruits, vegetables, growth, and processed foods. These films have a variety of uses, but in addition to the basic purpose of preventing the introduction of foreign substances, they have a function of maintaining freshness due to a moisture-permeable blocking effect, and it is difficult to prevent decay due to germs.

Accordingly, many studies have been conducted to impart antimicrobial properties to packaging films.

Antimicrobial agents can be largely divided into organic antibacterial agents and inorganic antibacterial agents. Organic antibacterial agents are easy to decompose and have problems in heat resistance, so their use is limited, and inorganic antibacterial agents are excellent in stability and heat resistance and have no volatility and elution, so the antibacterial activity lasts a long time. As a result, it has the advantage that its use and range of use are diverse.

Therefore, many attempts have been made to introduce antibacterial agents into various plastic products using inorganic antibacterial agents, and some commercialization has also been made.

If an antibacterial film containing an antibacterial agent is used in the packaging material, it can also have the effect of inhibiting the passage of bacteria on one side and inhibiting the proliferation of bacteria in the internal foods in contact with the antibacterial film.

Korean Patent Registration No. 10-1004027 discloses an antimicrobial food packaging film, but there is a problem in that the antimicrobial property is weak and the functionality is low as a single layer structure.

Republic of Korea Patent Registration No. 10-1004027: Antibacterial food packaging film

The present invention has been created to improve the above problems, and an object thereof is to provide an antimicrobial film having a multilayer structure having excellent antimicrobial properties.

The multilayer antibacterial film for packaging of the present invention for achieving the above object comprises: an inner layer having a thickness of 5 to 15 μm formed by mixing linear low-density polyethylene (LLDPE) and nano copper particles; An intermediate layer formed on the inner layer and formed of linear low-density polyethylene (LLDPE) and having a thickness of 20 to 40 μm; And an outer layer having a thickness of 10 to 20 μm formed by mixing linear low-density polyethylene (LLDPE) and nano copper particles and formed on the upper portion of the intermediate layer. The inner layer is formed by further mixing corn extract.

A coating layer formed on top of the outer layer; further comprising, wherein the coating layer is an acrylic solution, calcined starfish powder, ethylene tetrafluoroethylene, (3,3,3-trifluoropropyl) trimethoxysilane, fluorine alcohol, copper It is formed by coating with a coating liquid mixed with colloids.

As described above, the present invention has excellent antibacterial activity, so when used as a food packaging film, the freshness of food can be maintained and spoilage can be suppressed.

1 is a cross-sectional view of a multilayer antibacterial film for packaging according to an example of the present invention,
2 is a cross-sectional view of a multilayer antibacterial film for packaging according to another example of the present invention.

Hereinafter, a multilayer antibacterial film for packaging according to a preferred embodiment of the present invention will be described in detail.

Referring to FIG. 1, a multilayer antibacterial film 10 for packaging according to an example of the present invention is formed in a three-layer structure consisting of an inner layer 11, a middle layer 13, and an outer layer 15.

The inner layer 11 is formed by mixing nano-copper particles with a polyethylene resin. The thickness of the inner layer may be 5 to 15 μm.

Linear low density polyethylene (LLDPE) can be used as the polyethylene resin. Linear low density polyethylene may be a copolymer of ethylene and α-olefin. For example, it may be a copolymer of 80 to 90% by weight of ethylene and 10 to 20% by weight of α-olefin. Here, the α-olefin is a comonomer, and may be any one or a mixture of two or more of propylene, butene, pentene, hexene, octene, nocene, decene, and the like.

The linear low-density polyethylene is preferably polymerized using a metallocene catalyst rather than a Ziegler-Natta catalyst. Polyethylene polymerized using a metallocene catalyst has a more uniform structure than polyethylene polymerized using a Ziegler-Natta catalyst, and can increase elongation and tensile strength.

The nano copper particles may have a size of 10 to 100 nm. These nano-copper particles impart antibacterial properties to the inner layer.

The inner layer may be formed by extrusion molding by mixing 99 to 99.9% by weight of a polyethylene resin and 0.1 to 1% by weight of nano copper particles. In addition, it goes without saying that conventional additives such as an appropriate amount of plasticizer, dispersant, stabilizer, and pigment may be added in consideration of moldability, functionality and physical properties.

In addition, the inner layer may be formed by further mixing corn extract. For example, 94 to 98% by weight of a polyethylene resin, 0.1 to 1% by weight of nano copper particles, and 0.5 to 5% by weight of corn extract may be mixed and formed by extrusion molding.

The intermediate layer 13 is formed on the inner layer 11. The thickness of the intermediate layer may be 20 to 40 μm. The middle layer occupies the thickest part in the multilayer antibacterial film for packaging of the present invention.

The intermediate layer can be formed by extrusion molding a polyethylene resin. Linear low density polyethylene (LLDPE) can be used as the polyethylene resin. This linear low-density polyethylene is the same as that applied to the inner layer described above. In addition to the polyethylene resin, the intermediate layer may include an appropriate amount of conventional additives such as plasticizers, dispersants, stabilizers, and pigments in consideration of moldability, functionality, and physical properties.

Cellulose nanofibers (CNF) may be added to the intermediate layer to impart gas barrier properties. For example, 95 to 99% by weight of polyethylene resin and 1 to 5% by weight of cellulose nanofibers may be mixed and extruded to form an intermediate layer.

Cellulose nanofibers (CNF) refer to nano- or micrometer-sized rod-shaped particles or fibers in which cellulose chains are bound to form a bundle. Cellulose nanofibers may have a diameter of 5 to 100 nm and a length of 10 to 100 μm.

The outer layer 15 is formed on the middle layer 13. The thickness of the outer layer may be 10 to 20 μm. The outer layer is formed by mixing nano-copper particles with polyethylene resin.

Linear low density polyethylene (LLDPE) can be used as the polyethylene resin. This linear low-density polyethylene is the same as that applied to the inner layer described above.

The nano copper particles may have a size of 10 to 100 nm. These nano copper particles impart antibacterial properties to the outer layer.

The outer layer may be formed by extrusion molding by mixing 99 to 99.9% by weight of a polyethylene resin and 0.1 to 1% by weight of nano copper particles. In addition, it goes without saying that conventional additives such as an appropriate amount of plasticizer, dispersant, stabilizer, and pigment may be added in consideration of moldability, functionality and physical properties.

The multilayer antibacterial film 10 for packaging of the present invention described above can be manufactured by coextrusion. For example, while extruding each melted resin from three extruders through a T-die, three layers can be laminated to prepare an antibacterial film having a three-layer structure.

Meanwhile, in the present invention, a coating layer may be further formed as another example.

2, the multilayer antibacterial film 20 for packaging of the present invention has a coating layer 17 formed on the outer layer 15. The thickness of the coating layer may be 4 to 10 μm.

The coating layer is formed by coating with a coating solution in which an acrylic solution, fired starfish powder, ethylenetetrafluoroethylene, (3,3,3-trifluoropropyl)trimethoxysilane, fluorine alcohol, and copper colloid are mixed. The coating solution is 1 to 6 parts by weight of calcined starfish powder, 0.5 to 5 parts by weight of ethylene tetrafluoroethylene, 0.5 to 5 parts by weight of (3,3,3-trifluoropropyl) trimethoxysilane based on 100 parts by weight of the acrylic solution. , 2 to 8 parts by weight of fluorine alcohol, and 0.1 to 2 parts by weight of copper colloid may be mixed to form a composition.

An acrylic emulsion can be used as an acrylic solution. The fired starfish powder means that the starfish is fired at a high temperature (700 to 900°C) and then pulverized to a size of micrometers or nanometers. The fired starfish powder has a porous structure in which countless pores are formed on the surface and inside. The fired starfish powder having such a porous structure improves the releasability of the film and increases gas barrier properties.

Ethylene Tetra Fluoro Ethylene is a fluorine-bonded resin. Ethylene tetrafluoroethylene has a very low surface energy by relatively lowering contact with a material such as water droplets because no hydrogen bonds are formed. For this reason, the antifouling property can be improved, and the non-adhesive property and the releasability can be greatly improved. And (3,3,3-trifluoropropyl) trimethoxysilane (Trimethoxy (3,3,3-trifluoropropyl) silane) is a kind of fluorine silane, and serves to increase the bonding strength with the fired starfish powder particles. Since (3,3,3-trifluoropropyl)trimethoxysilane is a fluorine compound such as ethylenetetrafluoroethylene, fired starfish powder by addition of (3,3,3-trifluoropropyl)trimethoxysilane It binds strongly with ethylenetetrafluoroethylene between the particles.

As for fluorine alcohol, fluorine alcohol improves antifouling properties. tetrafluoro-1-propanol) can be used.

Copper colloid is a solution in which nano-copper particles are dispersed in a dispersion medium such as distilled water or alcohol. Copper colloids have an antibacterial role.

The coating solution can be coated on the surface of the outer layer by various methods such as evaporation coating, immersion coating, spin coating, and application.

Hereinafter, the present invention will be described through the following examples. However, the following examples are for explaining the present invention in detail, and are not intended to limit the scope of the present invention to the following examples.

(Example 1)

Each layer was configured as shown in Table 1 to prepare a three-layered film having a total thickness of 55 μm. The three-layer structured film was prepared using a 3-layer T-die cast extrustionn method.

division Furtherance thickness Outer layer LLDPE 99.5wt%, nano copper particles 0.5wt% 15㎛ Middle floor LLDPE 100wt% 30㎛ Inner layer LLDPE 99.5wt%, nano copper particles 0.5wt% 10㎛

(Example 2)

A coating solution of 8 μm was formed by applying a coating solution on the outer layer of the film of Example 1. The coating solution is acrylic emulsion 87wt%, calcined anthracite powder 3.5wt%, ethylene tetrafluoroethylene 2.5wt%, (3,3,3-trifluoropropyl) trimethoxysil 2.0wt%, trifluoroethanol 4.5wt% , 0.5wt% copper colloid was mixed to form a composition. The coating solution was applied using a spin coating method.

(Comparative example)

As a comparative example, linear low-density polyethylene (LLDPE) was extruded to prepare a single layer film having a thickness of 55 μm.

<Antibacterial test>

The films of Examples 1 and 2 and Comparative Examples were tested for antimicrobial against Escherichia coli and Staphylococcus aureus. The specimens of Examples 1 and 2 and Comparative Examples were cut to a size of 5 cm x 5 cm.

After placing the specimen on a sterilized standard film (sterilized polypropylene film), 0.1 ml of the strain culture was applied. After applying the culture medium, it was compressed with the same standard film, and the antimicrobial activity was measured after 48 hours. Antibacterial activity (%) was calculated by the following equation, and the results are shown in Table 2 below.

Antimicrobial activity (%) = {(number of bacteria in standard film after 48 hours-number of bacteria in specimen after 48 hours) / number of bacteria in standard film after 48 hours} × 100

division Antibacterial activity (%) Escherichia coli Staphylococcus aureus Example 1 99.9 99.9 Example 2 99.9 99.9 Comparative example 0 0

Referring to the results of Table 2, it was found that both Example 1 and Example 2 had excellent antimicrobial activity.

<physical property test>

Physical properties were tested for the films of Examples 1 and 2 and Comparative Examples in the following manner.

-Tensile strength: measured according to ASTM D882 standard.

-OTR Barrier property: In accordance with the standard measurement method of ASTM D3985, oxygen permeability (cc/m ² ·day · atm) at 0% relative humidity was measured using an air permeability meter, which was added over time after 90 days. Evaluated as.

-Roll unwindability: When the film is wound in a roll state and unwound by hand, it is evaluated as good if it is unwound without noise, and the degree of noise generated during unwinding is evaluated as normal or inferior. Evaluated.

(2) Experiment result

The experimental results are shown in Table 3 below.

division Example 1 Example 2 Comparative example The tensile strength
(gf/mm ² ) 269 315 227 OTR Barrier
(cc/m ² ·day·atm) 300~400 20-50 1000 or more After 90 days of OTR Barrier
(cc/m ² ·day·atm) 600~800 20-50 1000 or more Roll unwindability usually Good Thirteen

Referring to the results of Table 3, Examples 1 and 2 were superior to the comparative examples in elongation. This appears to be due to the multilayered structure. In particular, in the case of Example 2, it was found that the tensile strength was greatly improved as the coating layer was further formed.

The gas barrier property was the best in Example 2. Example 2 was found to continue to maintain excellent gas barrier properties even after 90 days. And it was found that only Example 2 was good in roll unwindability. In the case of Example 2, it appears to be the result of increasing the releasability by the coating layer.

In the above, the present invention has been described with reference to an embodiment, but this is only exemplary, and those of ordinary skill in the art will understand that various modifications and equivalent embodiments are possible therefrom. Therefore, the true scope of protection of the present invention should be determined only by the appended claims.

11: inner floor 13: middle floor
15: outer layer 17: coating layer

Claims (3)

An inner layer having a thickness of 5 to 15 μm formed by mixing 99 to 99.9% by weight of linear low-density polyethylene (LLDPE) and 0.1 to 1% by weight of nano copper particles;
An intermediate layer formed on the inner layer and formed of linear low-density polyethylene (LLDPE) and having a thickness of 20 to 40 μm;
An outer layer having a thickness of 10 to 20 μm formed by mixing 99 to 99.9% by weight of linear low-density polyethylene (LLDPE) and 0.1 to 1% by weight of nano copper particles, which is formed on the middle layer;
And a coating layer having a thickness of 4 to 10 μm to increase releasability and gas barrier properties by being formed on the outer layer,
The coating layer is 1 to 6 parts by weight of calcined starfish powder, 0.5 to 5 parts by weight of ethylenetetrafluoroethylene, 0.5 to 5 parts by weight of (3,3,3-trifluoropropyl)trimethoxysilane based on 100 parts by weight of the acrylic solution Part, a multi-layer antibacterial film for packaging, characterized in that formed by coating with a coating solution in which 2 to 8 parts by weight of trifluoroethanol and 0.1 to 2 parts by weight of copper colloid are mixed as fluorine alcohol. The multilayer antibacterial film for packaging according to claim 1, wherein the inner layer is formed by further mixing corn extract. delete

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