KR102190252B1 - Antimicrobial Film Having Nano ZnO Particle, Method of Making the Same and Food Packing Products - Google Patents

Abstract

A synthetic resin antibacterial film comprising 0.05% to 0.5% by weight of nano zinc oxide having an average particle diameter of 1 to 50 nm is disclosed. This antimicrobial film is a multi-layered or multi-layered synthetic resin layer containing a high concentration of nano zinc oxide and a low concentration synthetic resin layer containing no or low concentration of nano zinc oxide so as to increase antibacterial efficiency while reducing the content of nano zinc oxide. It can be made of a single layer of a high-concentration synthetic resin layer, and can be produced by a coextrusion multilayer film blow method. According to the present invention, an antibacterial film is produced and supplied using nano-zinc oxide, which is known to be harmless to the human body, so that there is no problem of harmfulness to the human body, and an antibacterial film that can be economically and technically competitive by realizing excellent antibacterial activity even with a small amount of addition. And food packaging products based on it can be supplied.

Description

Antimicrobial Film Using Nano Zinc Oxide, Its Manufacturing Method, and Food Packaging Products {Antimicrobial Film Having Nano ZnO Particle, Method of Making the Same and Food Packing Products}

The present invention relates to an antibacterial film, a manufacturing method thereof, and a food packaging product using the same, and more particularly, to an antibacterial film containing nano zinc oxide, a manufacturing method thereof, and a food packaging product using the same.

With the development of the industry, the demand for films using synthetic resins is rapidly increasing, and is used in many parts of daily life. Also. There is a growing demand for films with functionality, not general films, and recently, as interest in health increases, products with antibacterial properties with resistance to bacteria and bacteria have been developed and released.

In the case of food packaging materials, since food has a close relationship with health, the packaging material must first be one that does not elute harmful ingredients to the human body, and it is required that the internal food covered with the packaging material can be stored as long as possible without deterioration.

It is possible to think of spoilage in which biological factors are the main factor and simple spoilage in which chemical factors are the main factors that change food. Since these may have mutual effects, there is a limit to strict distinction between them.

In general, as one of the representative methods to prevent simple deterioration, it is a method of sealing food with food packaging and preventing spoilage or deterioration due to biological factors, preventing bacteria from passing through food packaging, and rapidly proliferating bacteria that have already entered the inside. Methods that prevent them from doing can be used. When an antibacterial film containing an antimicrobial substance is used in food packaging materials, it can suppress the passage of bacteria on one side and also have the effect of inhibiting the growth of bacteria in internal foods in contact with the antibacterial film.Therefore, many antibacterial films have been developed as food packaging materials. Is being used.

Recently, products using various antibacterial agents have been released. Organic antimicrobial agents are widely used as antibacterial agents, but there is a movement to refrain from using organic antibacterial agents due to increased tolerance and harmfulness to the human body due to their basic characteristics. Inorganic antibacterial agents and natural antimicrobial agents are used to replace organic antibacterial agents, but natural antibacterial agents have a problem that the antibacterial activity is expressed and the antibacterial persistence is lowered only when the cost is high and the amount added is large. In the case of inorganic antibacterial agents, the antibacterial persistence is good, but there is a problem of harm to the human body.

For example, due to the discovery of antimicrobial properties of silver nanoparticles, antibacterial synthetic resin products containing silver nanoparticles have been launched in various fields. In recent years, due to the problem of the harmfulness of the silver nano to the human body, the silver nano fever blew and disappeared suddenly in home appliances, and due to this situation, regulations on harmful substances are becoming stricter in both domestic and foreign countries.

Therefore, by fusion of nanotechnology with inorganic antibacterial agents with good antibacterial persistence, the amount of antibacterial activity is at least good, and the development of antibacterial agents that are harmless to the human body is underway.

Korean Patent Registration No. 10-1334283 Korean Patent Publication No. 10-2018-0071601

The present invention is to overcome the limitations of the above-described existing antibacterial film and food packaging material using the same, and its manufacturing, and is harmless to the human body, and an antimicrobial film that can be economically and technically competitive by implementing excellent antibacterial activity even with a small amount of addition, Its purpose is to provide a manufacturing method and a food packaging product using the same.

The antimicrobial film of the present invention to achieve the above object contains 0.05% by weight to 0.5% by weight based on the mass of nano-zinc oxide having an average particle diameter of 1 to 50 nm. In addition, the purity of nano zinc oxide is 99.9% or more.

In particular, in the present invention, in order to increase the antibacterial efficiency while reducing the content of nano zinc oxide, a plurality of high concentration synthetic resin layers containing nano zinc oxide in a high concentration and a low concentration synthetic resin layer containing nano zinc oxide in a low concentration The high-concentration synthetic resin layer may contain 0.05% by weight or more and 0.5% by weight or less of nano zinc oxide, and the low-concentration synthetic resin layer may include 0% by weight or more and 0.1% by weight or less of nano-zinc oxide. It is constructed so that the nano-zinc oxide content of the synthetic resin layer is higher than that of the low-concentration synthetic resin layer.

The antimicrobial film manufacturing method of the present invention for achieving the above object is characterized in that in the production of the antibacterial film of the present invention, a multilayer film blowing method by coextrusion of a high-concentration synthetic resin raw material and a low-concentration synthetic resin raw material.

In the present invention, the multilayer film constituting the antibacterial film may be a three-layer film in which a high-concentration synthetic resin layer is positioned on the outer layer, or may be simply composed of two layers, and may consist of only a high-concentration synthetic resin layer as one layer. It is preferable that the high-concentration synthetic resin layer is formed thinner than the low-concentration synthetic resin layer in order to increase the concentration of nano-zinc oxide.

In the case of forming the multilayer film into two layers in the present invention, the multilayer film is coextruded, expanded, and spread with a roller in the multilayer film blow method, and then cut at both ends in the width direction, and the inner layer film overlaps. It can be made by separating the center into two two-layer films using an interlayer slitter.

In the production of a high-concentration synthetic resin layer in the present invention, a raw material resin and a high-concentration master batch may be mixed and used, and a relatively low-concentration master batch itself may be used without mixing. Nano zinc oxide has good dispersibility when added in the form of a master batch (including 10% to 30% by mass), and 0.05% to 0.5% by mass is mixed with the resin in the form of one nanozinc oxide. It can also be used.

In the present invention, when the film is produced by the coextrusion blow method, the process can be proceeded by supplying a release material to the inside of the cylinder made of the inner synthetic resin layer, and the two separated when the center is separated from the rolled state in the form of a film. It is possible to use a method of simply pulling the part in a different direction, or at the same time making the center of the multilayer film easier to divide by using an interlayer slitter.

The food packaging product of the present invention may be made by processing the antibacterial film of the present invention, and may include various forms such as zipper bags, roll bags, sanitary bags, sanitary gloves, and wraps.

According to the present invention, an antibacterial film is produced and supplied using nano-zinc oxide, which is known to be harmless to the human body, so that there is no problem of harmfulness to the human body, and an antibacterial film that can be economically and technically competitive by realizing excellent antibacterial activity even with a small amount of addition. And food packaging products based on it can be supplied.

According to the method of the present invention, the antibacterial film of the present invention can be efficiently produced and supplied.

1, 2A and 2B are conceptual cross-sectional views showing a layer structure of a multilayer antibacterial film according to an embodiment of the present invention,
3A to 3D are process cross-sectional views schematically showing an intermediate step of the method of the present invention,
Figure 4 is a table showing one of the antibacterial test and anti-fungal test results conducted while varying the nano zinc oxide content,
5 is a photograph comparing before and after the test in which the antibacterial film of the present invention was applied to Staphylococcus aureus-resistant bacteria in the antibacterial test of the FITI Test Institute
6 and 7 are photographs comparing before and after the test to which the antibacterial film of the present invention was applied to each strain in the KOTITI Test Institute antibacterial test and antifungal test.
8 is an exemplary diagram of a test report for food container bonding of SGS (SGS).
9 is an exemplary diagram for the result of testing the content of SGS (SGS) bisphenol A (BPA).
10 is a photograph for explaining a food packaging product manufactured using the antibacterial film of the present invention.

Hereinafter, the present invention will be described in more detail through specific embodiments of the present invention with reference to the drawings.

1, 2A and 2B are cross-sectional views showing the antimicrobial film layer structure of the present invention.

In FIG. 1, the antimicrobial film 10 has a three-layer structure, and the relatively thick layer 11 in the middle is a low-concentration synthetic resin layer, which is a synthetic resin layer having a thickness of 40 micrometers (mic) made of polyethylene that does not contain any nano zinc oxide. , The thin layer 13 on both outer surfaces is a high-concentration synthetic resin layer, and is a synthetic resin layer of about 10 micrometers thick made of polyethylene containing 0.06% by weight of nano-zinc oxide.

In this case, when calculated as the total antibacterial film, it can be seen as an antibacterial film having approximately 0.02% by weight of nano-zinc oxide by mass. In this case, nano zinc oxide is used having a particle diameter of 1 to 50 nm and a purity of 99.9%.

Nano zinc oxide having such a particle size has been known to be harmless to humans through various existing experiments, and is semi-permanent due to the nature of inorganic substances and has excellent antibacterial persistence. In addition, nano-zinc oxide is known to have effects such as UV protection, retardation of resin degradation, and deodorization when used in a synthetic resin film.

Synthetic resin raw materials used as the base of the antibacterial film include polyolefin-based synthetic resins such as polyethylene (LDPE, LLDPE, HDPE, MDPE) or polypropylene (PP), polyethylene terephthalate (PET), ethylenyl vinyl acetate (EVA), and polyvinyl chloride ( PVC) or polyamide (PA) can be used.

In Figure 2a, the antibacterial film 20 has a simple two-layer structure, and the relatively thick layer 21 is a low-concentration synthetic resin layer, and is a 50-micrometer-thick synthetic resin layer made of polyethylene that does not contain any nano zinc oxide. , The remaining thin layer 23 is a synthetic resin layer having a thickness of 10 mic made of polyethylene containing 0.063% by weight of nano-zinc oxide as a high-concentration synthetic resin layer.

Even in this case, when calculated as the total antibacterial film, it can be seen as an antimicrobial film having approximately 0.01% by weight of nano zinc oxide by mass. At this time, nano-zinc oxide is used having a particle diameter of 1 to 50 nm and a purity of 99.9% or more.

Referring to Figure 2b, the antibacterial film 30 may have a simple one-layer structure, and is a thick high-concentration synthetic resin layer 31, in particular, as a synthetic resin layer made of polyethylene containing nano-zinc oxide, containing 0.06% by weight of nano-zinc oxide. It may be a synthetic resin layer having a thickness of 60 mic included.

Even in this case, when calculated as the total antibacterial film, it can be seen as an antimicrobial film having approximately 0.06% by weight of nano zinc oxide by mass. At this time, nano-zinc oxide has a particle diameter of 1 to 50 nm and a purity of 99.9% or more.

3A to 3D are cross-sectional views conceptually and schematically showing a method of manufacturing the multilayer antibacterial film as described above by a coextrusion blow method.

3A shows a front cross-section in which a high-concentration synthetic resin material melt layer 13' on the outside and a low-concentration synthetic resin material melt layer 11' on the inside are extruded in a concentric circle through coextrusion in a synthetic resin film extruder jig.

In the blow method, high-temperature air is blown into an empty space in the middle of the extruder jig to expand the synthetic resin material forming a concentric circle before it hardens, thereby increasing the width of the synthetic resin film to be made by this method.

3B shows a step of flattening two concentric circles made to have an approximately constant diameter through FIG. 3A to form a multilayer film. At this time, the coextruded product in the form of two concentric circles may have a shape as shown in FIG. 3B while passing between the rollers.

Since the two layers are integrated, the layer 11 is of the same material, so when the inner concentric circle is not solidified, it can be recognized as a single layer by being stuck to each other under pressure between passing through the rollers. The thin layers 13 on both sides of the middle layer 11 are connected to each other at both ends in the width direction, but form separate layers substantially spaced apart from each other.

If the antimicrobial film to be made has a layer structure as shown in FIG. 1, the multilayer film is sufficiently hardened in this state, and then it is wrapped around a storage roll for storage.

3C shows a state in which both sides in the width direction connecting the upper layers and the lower layers to each other in the width direction are removed by a slitter or the like as a next step additionally performed to make a simple two-layer film as in FIG. 2. In the step of Fig. 3c, the temperature of the low-concentration synthetic resin material layer forming a small concentric circle is sufficiently lowered and the surface is sufficiently hardened so that the two inner layers do not adhere well to each other even when passing between the rollers.

3D shows that both ends in the width direction of the multilayer film 20' are removed with a slitter, etc., and then the upper layers and the lower layers are separately pulled and wound on a roll to separate them. It is a side view showing a state in which the film 20 is made.

Here, not only the multilayer film is pulled separately from the top and bottom to separate each other, but also an interlayer slitter is installed between the upper and lower layers, even if the original two layers forming the center layer are slightly attached to each other, the interlayer slitter ( 40), so that separation can be done well.

On the other hand, in order to make a high-concentration synthetic resin material melt layer for the film extruder, a base synthetic resin material and nano zinc oxide must be prepared.In this case, instead of mixing directly in an extruder that prepares nano zinc oxide to be mixed with the base synthetic resin in powder form, it is first nano-oxidized. It is convenient to use a solidified masterbatch by uniformly mixing zinc fine powder and a small amount of base synthetic resin.

Therefore, in the extruder, the pellets of the base synthetic resin component and the master batch pellets are accurately supplied in a weight ratio according to the calculated content, mixed in a film extruder through heating and stirring, and extruded through an extruder jig under appropriate temperature and pressure conditions.

In the present invention, a multilayer antibacterial film of three or more layers may be used to impart various functions. To impart functionality, a functional material may be included in at least one of several layers. The functional material may be included in the form of an additive. In this case, in the form of adding additives, the base resin and additives are mixed in the form of a master batch or powder, and ZnO is used if necessary.

As additives, antistatic agents, dispersants, antioxidants, UV stabilizers, heat stabilizers, flame retardants, repellents, anti-drop agents, fillers, reinforcing agents, plasticizers, coloring agents, impact resistant agents, crosslinking agents, optical brighteners, anti-blocking agents, and slip agents are widely used. According to the use, there are slip agents, anti-blocking agents, dispersants, plasticizers, fillers, and antistatic agents to improve workability. To impart product functionality, there are flame retardants, repellents, anti-drop agents, antioxidants, biodegradants, etc., and for realizing product properties, antioxidants, UV stabilizers, heat stabilizers, antistatic agents, colorants, pigments, dyes, optical brighteners, reinforcing agents, And impact resistance.

In the case of a food packaging product in close contact with the antimicrobial film of the present invention, additives may be added to enhance the use or workability thereof. For example, for the efficiency of packaging work, a slip agent is used to improve when a problem occurs during work, and when blocking occurs, an anti-blocking agent is added, and when dispersion is difficult, a dispersant is prescribed to make the work well.

Recently, as a functional product, biodegradable substances are added to allow decomposition after use, antioxidants are added to improve long-term storage, and antifogging agents are added to prevent fogging to make the product visible.

In some cases, additives are used to realize the desired physical properties, such as prescribing a colorant when the product needs color in terms of the required properties, or adding an ultraviolet (UV) stabilizer when the content is sensitive to UV or is vulnerable to UV.

The content of the additives as described above can be variously adjusted according to the material properties and the use of the film to be made, and the weight ratio is generally in the range of 0.1 to 10%. If it is too much, it may cause problems in production and processability as a film, and if it is too little, it becomes difficult to realize the functionality that is the purpose of adding an additive.

The thickness of the antibacterial film can be manufactured differently depending on the use, but is usually manufactured in 10 mic to 150 mic.

Looking more at the manufacturing method of this embodiment, for the convenience of controlling the content, nano zinc oxide uses a master batch instead of powder, and a co-extrusion dry blow or BLOWN method is used in an extruder for film extrusion.

First, the nano zinc oxide masterbatch and the base resin pellets according to the purpose of the product to be made are placed in the mixing space in the extruder and heated and mixed. The nano-zinc oxide content of the master batch is preferably 10 to 30%, and 10% by weight of nano-zinc oxide is used here.

When making high- and low-concentration synthetic resin materials, they are sufficiently kneaded with synthetic resin raw materials and blown extrusion is performed through a coextrusion jig when the temperature reaches 150°C to 300°C, which is a suitable temperature for extrusion. Blow speed is usually 300 ~ 2000RPM, here the work was done at 600 ~ 1000RPM. Antibacterial films of various thicknesses were produced by controlling conditions such as extrusion jig temperature, blow speed, and air pressure.

The antibacterial film thus produced is processed by each processing machine to produce food packaging products (zipper bag 54, roll bag 51, sanitary bag 55, sanitary gloves 53, wrap 52) as shown in Table 1 below. I did. At this time, there was no problem with the product, such as workability, transmittance, and adhesion to the sealing part.

product SPEC Machinability (workability) Checklist Zipper bag SIZE: Width 25cm(30cm)*Length 30cm
Thickness: 60micro/mic
Zipper (color double zipper)
Material: LDPE
Nano ZnO content: 6000PPM (0.06%) good
(No problem) For the transmittance by using a small amount
No big change.
No problem when sealing. Rollback SIZE: Width 25cm(35cm)*Length 35cm
Thickness: 15~20mic
Material: HDPE
Nano ZnO content: 6000PPM (0.06%) good
(No problem) No problem when sealing Plastic bag SIZE: Width 25cm*Length 35cm
Thickness: 10~15mic
*M character
Material: HDPE
Nano ZnO content: 6000PPM(0.06%) good
(No problem) No problem when sealing Vinyl gloves SIZE: Width 22.5cm*Length 27.5cm
Thickness: 27~28mic
Material: LDPE
Nano ZnO content: 6000PPM (0.06%) good
(No problem) No problem when sealing lab Nano ZnO content: 6000PPM (0.06%) good
(No problem) For the transmittance by using a small amount
No big change

On the other hand, as a result of the antibacterial evaluation for each sample of the antimicrobial film obtained by varying the amount of the preparation method as described above, the results shown in the table of Fig. 4 and the photographs of Figs.

It can be seen that even though the content of 0.05% to 0.5%, which is lower than the conventionally used content, is applied, it has an antibacterial effect without problems in product use. In the antibacterial test of Figure 4, JIS Z 2801 film adhesion method, Escherichia coil ATCC 2692 for E. coli strain, Staphylococcus aureus ATCC 6538 for Staphylococcus aureus strain, and Klebsiella pneumoniae ATCC 4352 for pneumococcal strain were remarkable in all cases. It showed a reduction rate. Chaetomium globosum was used as a fungus in the ASTM G21 anti-mold test for the anti-fungal test of FIG. 4, and the mold did not grow at all contents.

5 is a photograph comparing before and after the test of the 0.06% antibacterial film of the present invention using MRSA Staphylococcus aureus ATCC33591 as a strain of Staphylococcus aureus resistant bacteria by the ASTM E2149 shake flask method in the antibacterial test of the FITI Test Institute. , 99.9% of antibacterial activity was recorded.

Figure 6 is the present invention using the E. coli strain Escherichia coil ATCC 2692, Staphylococcus aureus ATCC 6538 for Staphylococcus aureus strain, and Klebsiella pneumoniae ATCC 4352 as the pneumococcal strain in the antibacterial test of KOTITI This is a picture comparing before and after the test of 0.06% antibacterial film of, and the test result recorded 99.9% of antibacterial activity in all cases.

7 is a picture comparing before and after the test of the 0.06% antibacterial film of the present invention, using Chaetomium globosum as a fungus of the ASTM G21 anti-mold test in the anti-fungal test of KOTITI Test Institute, it was found that the mold did not grow.

FIG. 8 is a report of a food container conjugation test of SGS (SGS), and shows the results suitable for all standards required by the Ministry of Food and Drug Safety.

9 is a result of testing the content of SGS (SGS) bisphenol A (BPA), N.D. (Not found) The results are shown. It can be viewed as BPA Free.

10 illustrates food packaging products produced using the developed antibacterial film, that is, a zipper bag 54, a roll bag 51, a sanitary bag 55, a sanitary glove 53, and a wrap 52.

From the above results, in the case of manufacturing by applying nano zinc oxide to an antibacterial film, other antibacterial agents such as organic antibacterial agents have a problem of generating antibacterial activity at a high temperature of extrusion processing, but nano zinc oxide has a high melting point as an inorganic substance. Also, because it maintains the antibacterial activity in the state of nanoparticles, extrusion processing and film production were possible.

It was confirmed that there was no difficulty in manufacturing the film by adding a small amount, and in the case of the prepared antibacterial film, excellent results were obtained in antibacterial and antifungal tests. And, in manufacturing a food packaging film, the processability and transparency were good, and it was good for food packaging purposes, and the film surface condition was also very good.

In the above, the present invention has been described through limited embodiments, but this has been illustratively described to aid understanding of the present invention, and the present invention is not limited to these specific embodiments. Therefore, those of ordinary skill in the field to which the present invention belongs can implement various changes or application examples based on the present invention, and it is natural that such modifications or application examples belong to the appended claims.

10, 20, 30: antibacterial film
40: interlayer slitter

Claims (7)

A low-concentration synthetic resin layer made of synthetic resin raw materials;
Including two high-concentration synthetic resin layers made of 0.05% to 0.5% by weight of nano zinc oxide and the synthetic resin raw material,
The nano zinc oxide has a particle diameter of 1 nm to 50 nm,
The synthetic resin raw material is any one of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), ethylene vinyl acetate (EVA), polyvinyl chloride (PVC), and polyamide (PA),
The low-concentration synthetic resin layer is a synthetic resin antibacterial film disposed between the two high-concentration synthetic resin layers.
delete The method of claim 1,
The synthetic resin antibacterial film, characterized in that the thickness of the high-concentration synthetic resin layer is thinner than that of the low-concentration synthetic resin layer. A low-concentration synthetic resin layer made of synthetic resin raw materials;
Including two high-concentration synthetic resin layers made of 0.05% to 0.5% by weight of nano zinc oxide and the synthetic resin raw material,
The nano zinc oxide has a particle diameter of 1 nm to 50 nm,
The synthetic resin raw material is any one of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), ethylene vinyl acetate (EVA), polyvinyl chloride (PVC), and polyamide (PA). ,
Co-extruding the low-concentration synthetic resin layer into an inner layer film, and coextruding the high-concentration synthetic resin layer into an outer layer film;
Expanding the synthetic resin raw material before hardening;
Passing the low-concentration synthetic resin layer and the high-concentration synthetic resin layer through a roller;
Removing both sides in the width direction from the low-concentration synthetic resin layer and the high-concentration synthetic resin layer;
Separating the low-concentration synthetic resin layer into two synthetic resin antibacterial films using an interlayer slitter
Synthetic resin antibacterial film manufacturing method comprising a.
delete As a food packaging product made by processing the synthetic resin antibacterial film of claim 1 or 3,
A product for food packaging using an antibacterial film, characterized in that it is any one of a zipper bag, roll bag, sanitary bag, sanitary gloves, and wrap.
The method of claim 1,
The low-concentration synthetic resin layer or the high-concentration synthetic resin layer,
A synthetic resin antibacterial film containing 0.1% to 10% of one or more of an antioxidant, a repellent, an anti-drop agent, a plasticizer, a colorant, a crosslinking agent, an optical brightener, and a biodegradant.

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