KR20200045601A - Antimicrobial Film Having Nano ZnO Particle, Method of Making the Same and Food Packing Products - Google Patents

Abstract

Disclosed is a synthetic resin antibacterial film comprising 0.05 to 0.5 wt% of nano-zinc oxide having an average particle size of 1 to 50 nm. To enhance antibacterial efficiency while reducing the content of nano-zinc oxide, the antibacterial film is composed of a multilayer having a high concentration synthetic resin layer including high concentrations of nano-zinc oxide and a low concentration synthetic resin layer including no or low concentrations of nano-zinc oxide and is composed of a single layer which is a synthetic resin layer of high concentrations, and is produced by a co-extrusion multilayer film blow method. According to the present invention, an antibacterial film and a food packaging product based thereon can be provided, wherein the antibacterial film is produced and supplied by using nano-zinc oxide, which is known to be harmless to a human body, not to have a problem of harmfulness to a human body, and exhibits excellent antibacterial power even with a small addition to secure economical and technical competitiveness.

Description

Antibacterial film using nano zinc oxide, its manufacturing method and food packaging product {Antimicrobial Film Having Nano ZnO Particle, Method of Making the Same and Food Packing Products}

The present invention relates to an antibacterial film, a method for manufacturing the same, and a food packaging product using the same, and more particularly, to an antibacterial film containing nano zinc oxide, a method for manufacturing the same, 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. In addition. There is an increasing demand for films that impart functionality rather than general films, and recently, as interest in health has increased, products with antimicrobial resistance to bacteria and bacteria have been developed and released.

In the case of food packaging materials, since foods have a close relationship with health, the packaging materials must first be that the components that are harmful to the human body do not elute, and it is required that the internal food covered with the packaging material can be stored for a long time in a state that does not change as much as possible.

Changing food can be thought of as the main decay of biological factors and the simple deterioration of chemical factors, but since they can affect each other, there is a limit to stricting these divisions.

Usually, as one of the representative methods for preventing simple deterioration, the food is sealed with food packaging material, and the bacteria are prevented from passing through the food packaging material by preventing decay or deterioration caused by biological factors. A method to prevent this can be used. The use of antimicrobial films containing antimicrobial substances in food packaging materials can also inhibit the passage of bacteria on one side, and also have the effect of inhibiting the growth of bacteria in the internal food that comes into contact with the antibacterial film, so many antibacterial films have recently been developed as food packaging materials. Has been used.

Recently, products using various antibacterial agents have been released. Although organic antibacterial agents are frequently used as antibacterial agents, organic antibacterial agents have a movement to refrain from use due to increased resistance and harmful effects to the human body. In order to replace the organic antibacterial agent, an inorganic antibacterial agent and a natural antibacterial agent are used, but the natural antibacterial agent has a problem that the antimicrobial activity is exhibited and the antimicrobial persistence is lowered only when the unit price is high and the amount added is large. In the case of inorganic antimicrobial agents, the antimicrobial persistence is good, but there is a problem in human health.

For example, due to the discovery of the antibacterial properties of silver nanoparticles, antibacterial synthetic resin products containing silver nanoparticles have been released in various fields. In recent years, as the human body's harmfulness has been a problem, silver nano fever has blown to household appliances, and suddenly disappeared. Due to this situation, regulations on hazardous substances in countries around the world have become strict.

 Therefore, by adding nano-technology to inorganic antibacterial agents with good antimicrobial persistence, the added amount is at least good for antimicrobial activity, and development of a harmless antimicrobial agent is in progress.

Republic of Korea Patent Registration No. 10-1334283 Republic of Korea Patent Publication No. 10-2018-0071601

The present invention is to overcome the limitations of the existing antimicrobial film and food packaging material using the same and the manufacturing of the above, it is harmless to the human body, antimicrobial film that can be economically and technically competitive by realizing excellent antibacterial power even with a small amount added, It is an object of the present invention to provide a food packaging product using the manufacturing method.

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

Particularly, in the present invention, a plurality having a high concentration synthetic resin layer containing high concentrations of nano-zinc oxide and a low concentration synthetic resin layer not containing nano-zinc oxide or containing low concentrations to increase the antibacterial efficiency while reducing the content of nano zinc oxide. It may be made of a layer, the high-concentration synthetic resin layer may be made of nano-zinc oxide containing 0.05% by weight or more and 0.5% by weight or less, and the low-concentration synthetic resin layer may contain nano-zinc oxide by 0% by weight or more and 0.1% by weight or less, and high concentration It is configured such that the content of nano zinc oxide in the synthetic resin layer is higher than that of nano zinc oxide in the low concentration synthetic resin layer.

The method for producing an antimicrobial film of the present invention for achieving the above object is characterized in that, in the production of the antimicrobial film of the present invention, a multi-layer film blow method is performed by coextrusion of a high-concentration synthetic resin raw material and a low-concentration synthetic resin raw material.

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

In the case of forming a multi-layer film in two layers in the present invention, the multi-layer film is co-extruded with an inner layer film and an outer layer film in a multi-layer film blow method, expanded, and then spread with a roller, and then cut 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 resin and a high-concentration masterbatch may be used in combination, and a relatively low-concentration masterbatch itself may be used without mixing. Nano-zinc oxide is good to disperse in the form of masterbatch (including 10% to 30% by weight), and nano-zinc oxide is mixed with resin in a particle size of 0.05% to 0.5% by weight. It can also be used.

In the present invention, when the film is produced by the coextrusion blow method, a release material can be supplied to the inside of a cylinder made of an inner synthetic resin layer, and the two separated when the center is separated in the state of being stretched in the form of a film through a roller. It is possible to use a method of easily pulling a portion in a different direction, or at the same time, to easily divide the center of a multi-layer film 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 a zipper bag, a roll bag, a sanitary bag, a sanitary glove, and a wrap.

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 food packaging products based on the same.

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 multi-layered antibacterial film according to an embodiment of the present invention,
3A to 3D are process cross-sectional views schematically showing intermediate steps of the method of the present invention,
Figure 4 is a table showing one of the results of antibacterial and antifungal tests conducted while varying the nano zinc oxide content,
5 is a photograph comparing the before and after the test of applying the antimicrobial film of the present invention to Staphylococcus aureus resistant bacteria in the antibacterial test of the FITI Testing Institute
6 and 7 are pictures comparing the before and after the test of applying the antibacterial film of the present invention to each strain in the antibacterial test and antifungal test of the KOTITI Research Institute.
8 is an exemplary view of a test report of SGS (SGS) food container adhesion test.
9 is an exemplary view of the results of SGS (SGS) bis wasteol A (BPA) content test.
10 is a picture for explaining a food packaging product produced 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 layer structure of the antimicrobial film of the present invention.

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

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

Nano zinc oxide having such a particle size is known to be harmless to the human body through various experiments, and is semi-permanent in nature and has excellent antibacterial persistence. In addition, nano zinc oxide is known to have effects such as UV protection, resin deterioration delay, and deodorization when used in synthetic resin films.

The raw materials for synthetic resins that are the base of antimicrobial films include polyolefin-based synthetic resins such as polyethylene (LDPE, LLDPE, HDPE, MDPE) or polypropylene (PP), polyethylene terephthalate (PET), ethylene vinyl acetate (EVA), and polyvinyl chloride ( PVC) or polyamide (PA).

In FIG. 2A, the antimicrobial film 20 has a simple two-layer structure, and the relatively thick layer 21 is a low-concentration synthetic resin layer and is a synthetic resin layer having a thickness of 50 micrometers (mic) made of polyethylene that does not contain nano zinc oxide at all. , The remaining thin layer 23 is a high concentration synthetic resin layer and is a synthetic resin layer having a thickness of 10 mic of a polyethylene material containing 0.063% by weight of nano zinc oxide.

Even in this case, when calculated as the total antibacterial film, it can be regarded as an antibacterial film having nano zinc oxide of about 0.01% by weight. At this time, the nano-zinc oxide particles having a particle size of 1 to 50 nm and a purity of 99.9% or more are used.

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

Even in this case, when calculated as the total antibacterial film, it can be regarded as an antibacterial film having approximately 0.06% by weight of nano zinc oxide on a mass basis. At this time, the nano-zinc oxide particles having a particle size of 1-50 nm and a purity of 99.9% or more are used.

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

Figure 3a shows a cross-section of the high-density synthetic resin material melt layer 13 'and the low-density synthetic resin material melt layer 11' on the inside are extruded together in a concentric form through co-extrusion in a synthetic resin film extruder jig.

In the blow method, the extruder jig serves to increase the width of the synthetic resin film to be produced in this way by expanding the synthetic resin material constituting concentric circles by blowing hot air into the empty space in the middle.

Figure 3b shows the step of processing into a multi-layer film form by flattening two concentric circles made to have a substantially constant diameter through Figure 3a. At this time, the co-extruded product in the form of two concentric circles may have the shape shown in FIG. 3B while passing between rollers.

Since the two layers are integrated, the layer 11 is made of the same material, and can be recognized as one layer by being pressed against each other while passing through the roller when the inner concentric circles are not solid. The thin layers 13 on both sides of the middle layer 11 form mutually separate but substantially separate layers at both ends in the width direction.

If the antimicrobial film to be made has a layer structure as shown in FIG. 1, in this state, the multilayer film is sufficiently hardened, and the roll may be stored in a storage roll.

FIG. 3C shows a state in which both sides in the width direction connecting the upper layers and the lower layers are removed by slitters as a next step additionally performed to make a simple two-layer film as shown in FIG. 2. In the step of FIG. 3C, the low concentration synthetic resin material layer constituting a small concentric circle is sufficiently low in temperature and sufficiently hardened to prevent the two inner layers from sticking together even when passing between rollers.

Figure 3d is a multi-layer film 20 ', as shown in Figure 3c, both ends in the width direction are removed by a slitter, etc., while pulling the upper layers and lower layers separately while winding and separating them into two layers of upper and lower antibacterial It is a side view showing the state in which the film 20 is made.

Here, the multi-layer film is pulled separately to the upper and lower portions to separate them from each other, and even if the original two layers constituting the central layer are weakly attached to each other by installing an interlayer slitter between the upper and lower layers, the interlayer slitter ( With the help of 40), separation can be done well.

On the other hand, in order to make a high-concentration synthetic resin material melt layer for a film extruder, a base synthetic resin material and nano zinc oxide must be prepared. Instead, nano zinc oxide to be mixed with the base synthetic resin is directly mixed in a powder extruder instead of being directly mixed in a nano oxidation. It is convenient to use a masterbatch that is uniformly mixed with zinc fine powder and a small amount of base synthetic resin.

Therefore, the extruder accurately feeds the pellets of the base synthetic resin component and the masterbatch pellets in a weight ratio according to the calculated content, mixes them in a film extruder through heating and stirring, and extrudes them through an extruder jig under suitable temperature and pressure conditions.

In the present invention, a multi-layer antibacterial film having three or more layers may be used to impart various functionalities. For imparting functionality, a functional material may be included in at least one of several layers. Functional materials can be included in the form of additives. In this case, in the form of adding additives, the base resin and additives in the form of a masterbatch or powder are mixed with ZnO as necessary.

As additives, anti-static agents, dispersants, antioxidants, UV stabilizers, heat stabilizers, flame retardants, repellents, inert agents, fillers, reinforcing agents, plasticizers, colorants, impact resistance agents, crosslinking agents, fluorescent whitening agents, anti-blocking agents, slip agents, etc. are frequently used. , When classified according to the use, there are slip agents, antiblocking agents, dispersants, plasticizers, fillers, antistatic agents, etc. for improving workability. Flame retardants, repellents, anti-dropping agents, antioxidants, biodegradants, etc. are used to impart product functionality, and antioxidants, UV stabilizers, heat stabilizers, antistatic agents, colorants, pigments, dyes, fluorescent brighteners, reinforcing agents, etc. And shockproof agents.

In the case of food packaging products close to the antimicrobial film of the present invention, additives may be added to increase its use or workability. For example, in order to improve packaging work efficiency, slip agents are used to improve when problems occur during work, antiblocking agents are added when blocking occurs, and dispersing agents are prescribed by dispersing agent to ensure good work.

In recent years, as a functional-improving product, biodegradable materials are added so that they can be decomposed after use, antioxidants are added to improve long-term storage, and anti-fogging agents are added to prevent fogging.

Additives may be used to achieve desired properties, such as prescribing a colorant when the product requires color in the physical properties required, or adding an ultraviolet (UV) stabilizer when the content is vulnerable to UV or the contents are sensitive to UV.

The additives as described above can be variously adjusted according to the material properties and the purpose of the film to be made, and a weight ratio of 0.1 to 10% is suitable. Too much can cause problems with production and processability as a film, and too little will make it difficult to realize the functionality that is the purpose of adding additives.

The thickness of the antimicrobial film can be prepared differently depending on the application, but is usually produced in 10mic to 150mic.

Looking at the manufacturing method of this embodiment a little more, for the convenience of control of the content, nano zinc oxide uses a master batch instead of a powder, and uses a coextrusion dry blow or blow (BLOWN) method in an extruder for film extrusion.

First, the nano-zinc oxide master batch and the base resin pellet according to the application of the product to be produced are placed in a mixing space in the extruder and heated and mixed and transferred. The nano-zinc oxide content of the master batch is 10 to 30%, and the nano-zinc oxide content of 10% by weight is used.

When making synthetic resin materials of high and low concentrations, when the synthetic resin raw materials are sufficiently kneaded and the temperature suitable for extrusion is 150 ° C to 300 ° C, blow extrusion is performed through a coextrusion jig. Blow speed is usually 300 ~ 2000RPM, the work was done here 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 produced in this way is processed by each processing machine to produce food packaging products (zip bags 54, roll bags 51, sanitary bags 55, sanitary gloves 53, wraps 52) as shown in Table 1 below. Did. At this time, there were no problems with the product such as processability, permeability, and sealing part adhesion.

product SPEC Processability (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 small amount use, permeability
No big change.
No problem when sealing. Roll back 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 letter
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 small amount use, permeability
No big change

On the other hand, as a result of antibacterial evaluation of each antimicrobial film sample obtained by varying the content in the above-described manufacturing method, the results as shown in the table of Figure 4 and Figures 5 to 9 were obtained.

It can be seen that even when a content of 0.05% to 0.5%, which is lower than the content normally used, is applied, it has an antimicrobial effect without problem in using the product. In the antibacterial test of Figure 4, the results of experiments using JIS Z 2801 film adhesion method, Escherichia coil ATCC 2692 for E. coli strains, Staphylococcus aureus ATCC 6538 for Staphylococcus aureus strains, and Klebsiella pneumoniae ATCC 4352 for pneumococcal strains are remarkable in all cases The reduction rate was shown. Chaetomium globosum was used as a fungus in the ASTM G21 anti-microbial test for the antifungal test of FIG. 4 and the fungus did not grow at all contents.

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

Figure 6 is the present invention using the ASTM E2149 shake flask method in the antimicrobial test of the KOTITI Research Institute E. coli strain Escherichia coil ATCC 2692, Staphylococcus aureus strain Staphylococcus aureus ATCC 6538, pneumococcal strain Klebsiella pneumoniae ATCC 4352 It is a picture comparing 0.06% of the antibacterial film before and after the test, and the results of the experiment recorded 99.9% of the antibacterial activity in all cases.

FIG. 7 is a photograph comparing Chaetomium globosum as a fungus of ASTM G21 anti-microbial test in the anti-fungal test of the KOTITI Research Institute, and before and after the test of the 0.06% antimicrobial film of the present invention, showing that the fungus cannot grow.

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

9 is a test result of SGS (SGS) bis wasteol A (BPA) content, N.D. (Not found) The results were shown. It can be viewed as BPA free.

10 illustrates a food packaging product manufactured 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.

In view of 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 in the case of nano zinc oxide, it has a high melting point as an inorganic substance and high temperature. Even 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 the film for food packaging, it has good processability and transparency, and was good for food packaging applications, and the surface condition of the film was also very good.

In the above, the present invention has been described through limited embodiments, but the present invention is not limited to these specific embodiments, which are merely illustratively described to help understanding of the present invention. Therefore, a person having ordinary knowledge in the field to which the present invention pertains may make various modifications or application examples based on the present invention, and it is obvious that such modifications and application examples belong to the appended claims.

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

Claims (6)

The synthetic resin raw material contains 0.05 to 0.5% by weight of nano zinc oxide having a particle diameter of 1nm to 50nm, based on mass.
The synthetic resin raw material is polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), ethylene vinyl acetate (EVA), polyvinyl chloride (PVC), polyamide (PA) synthetic resin characterized in that it is made of any one of Antibacterial film. According to claim 1,
It consists of a single layer consisting of only a high-density synthetic resin layer containing high concentrations of nano-zinc oxide and multiple layers with low-concentration synthetic resin layers containing no or low concentrations of nano-zinc oxide.
The high-concentration synthetic resin layer contains nano zinc oxide in an amount of 0.05 wt% to 0.5 wt% or less, and the low-concentration synthetic resin layer contains nano zinc oxide in an amount of 0 wt% or more and 0.1 wt% or less. Synthetic resin antibacterial film, characterized in that the content of nano zinc oxide in the synthetic resin layer is higher than that of the low concentration synthetic zinc oxide. According to claim 2,
The thickness of the high concentration synthetic resin layer is a synthetic resin antibacterial film, characterized in that thinner than the thickness of the low concentration synthetic resin layer. In preparing the synthetic resin antibacterial film of any one of claims 1 to 3,
A method of manufacturing a synthetic resin antimicrobial film, characterized in that it is produced by a multi-layer film blow method by coextrusion of a raw material of a high concentration synthetic resin layer with a relatively high content of nano zinc oxide and a raw material of a low concentration synthetic resin layer with a relatively low content of nano zinc oxide. The method of claim 4,
The multi-layer film produced by the multi-layer film blow method is composed of a two-layer or three-layer film, and the multi-layer film blow method coextrudes the inner layer film and the outer layer film, expands it, expands it with a roller, and cuts both ends in the width direction. And, the method of manufacturing a synthetic resin antibacterial film, characterized in that made by separating the center of the inner layer film into two two-layer film using an interlayer slitter. A food packaging product made by processing the antibacterial film of any one of claims 1 to 3,
Product for food packaging using antibacterial film, characterized in that it is one of a zipper bag, a roll bag, a sanitary bag, a sanitary glove, and a wrap.

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