KR102220356B1 - Single-layer Antimicrobial Shrinkable Film - Google Patents

Abstract

The present invention relates to a single-layer antibacterial shrinkable film obtained by mixing 70.0-88.0 wt% of linear low-density polyethylene (LLDPE), 10.0-20.0 wt% of low-density polyethylene (LDPE), and 2.0-10.0 wt% of an antibacterial copper masterbatch (M/B) containing a mixture of 70.0-90 wt% of low density polyethylene (LDPE), 5.0-15.0 wt% of antibacterial copper including spherical copper oxide having an average diameter of 1-6 micrometers and 5.0-15.0 wt% of spherical calcium oxide having an average diameter of 1-6 micrometers. The single-layer antibacterial shrinkable film realizes antibacterial properties and shrinking at the same time, exhibits antibacterial activities at both surfaces of the film to inhibit proliferation of microorganisms throughout the film and to maintain the freshness of packaged food for a long time. In addition, the single-layer antibacterial shrinkable film has a specific compositional ratio of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), and thus uniform shrinking occurs upon the integrated packaging, no wrinkle is generated on the shrunk film, shrinking is performed with a suitable balance in the machine direction (MD) and the transverse direction (TD), and has a single-layer structure to provide improved productivity and a small thickness.

Description

Single-layer Antimicrobial Shrinkable Film}

The present invention relates to a single antibacterial shrink film, and more specifically, a composition ratio of polyethylene (PE)-based resin is specified, and the antimicrobial copper obtained by master batch (MB) is mixed to package food by shrinkage, and the antibacterial activity of the antibacterial copper is applied to both sides of the film. It relates to a single antimicrobial shrinking film that can be expressed in, suppress the growth of microorganisms and maintain the freshness of packaged food for a long time.

In general, antibacterial copper is a natural material that is very effective in preventing infectious diseases and cross-infection by acting on bacteria and viruses such as Escherichia coli and food poisoning bacteria as it naturally generates antibacterial activity as copper or a copper alloy with a copper content of more than 60%. It is a human-friendly antibacterial material.

The antibacterial copper has little variation in antibacterial activity regardless of the particle size, and does not generate resistant bacteria over time, so it is far superior to silver (nano) or ceramic materials, and the antibacterial activity is not affected by external environment such as heat or humidity, It is a semi-permanent, natural antibacterial material that is harmless to the human body and environment, and does not require any chemical addition due to the antimicrobial properties of copper itself.

Looking at the antibacterial film of the prior art using the antibacterial copper, Korean Patent Publication No. 10-1997000 antibacterial film (October 01, 2019) is the first LLDPE composed of Linear Low Density Polyethtlene (LLDPE). layer; A second LLDPE layer composed of linear low-density polyethylene; And an antimicrobial copper layer comprising at least 8% by weight of an antibacterial copper-containing additive, wherein the antimicrobial copper-containing additive comprises 75% by weight of LDPE and 25% by weight of Antimicrobial Copper, wherein the antibacterial The copper-containing additive contains 75% by weight LDPE and 25% by weight Antimicrobial Copper, and the antimicrobial copper-containing additive is injection-molded by master batch blending or compounding blending, but low density polyethylene (Low Density Polyethylene). Polyethtlene; LDPE) is mixed with an antibacterial copper powder as a raw material, and a dispersant based on an ester compound and a desiccant based on calcium oxide are mixed, and the antibacterial copper powder comprises 70% by weight of a spherical powder obtained by processing antibacterial copper into a powder. , It is a composition in which 30% by weight of flake-type powder processed into powder is mixed.

The antimicrobial film of the prior art is a multilayer film, so that the antibacterial activity of the antibacterial copper is not expressed from the antibacterial copper layer to the first layer, so bacteria and viruses live on the outer surface of the packaged antibacterial film, and the film becomes unnecessarily thick due to the multilayer, thereby increasing productivity. There is a problem of deterioration.

In addition, the antibacterial film does not shrink and thus cannot be used for shrink packaging for various containers such as PET beverage bottles, glass containers, beverages and alcohol cans.

In addition, when the antibacterial film is composed of only an antibacterial copper layer, the base is composed of only low-density polyethylene (LDPE), so that the strength and elongation are higher than that of the base antibacterial film of linear low-density polyethylene (LLDPE) or high-density polyethylene (HDPE). There is a small problem.

In general, shrink film refers to a film used for packaging products by inducing shrinkage of the film in one or both directions by heat at a constant temperature. PET beverage bottles, glass containers, beverages using the shrinking property of shrinkage by heating And various containers such as alcohol cans, such as shrink packaging, shrink label, cap-seal, battery packaging, etc. It is widely used for ease of identification and convenience of manual and automatic transfer.

In general, shrink films are manufactured by blown film molding, and are stretched in the machine direction (MD: Machine Direction) and transverse direction (TD: Transverse Direction) when the film is manufactured, cooled with stress, and manufactured by shrink wrapping. After packaging the product used in the process, it induces stress relief through heat treatment, resulting in shrinkage.

Shrink films of the prior art are using polyvinyl chloride (PVC), polystyrene (PS), polyethylene (PE), polyester (PET), and the like.

Looking at the polyethylene (PE)-based shrink film of the prior art, the triple polyethylene-based heat-shrinkable film (October 14, 2013) of Korean Patent Publication No. 10-1317856 is a triple layer consisting of a surface layer, an intermediate layer, and an inner layer. In the shrink film, the surface layer contains 7 to 55% by weight of low density polyethylene (LDPE) resin, 15 to 87% by weight of linear low density polyethylene (LLDPE) resin, and 3 to 45% by weight of metallocene linear low density polyethylene (mLLDPE) resin. %, high-density polyethylene (HDPE) resin contains 2 to 12% by weight, anti-blocking agent (ab) 0.5 to 1.5% by weight, antistatic agent (as) 0.5 to 1.5% by weight; The intermediate layer contains 5 to 45% by weight of a low density polyethylene (LDPE) resin, 20 to 89% by weight of a linear low density polyethylene (LLDPE) resin, 3 to 40% by weight of a metallocene linear low density polyethylene (mLLDPE) resin, and a high density polyethylene ( HDPE) resin comprises 3 to 7% by weight; The inner layer contains 7 to 45% by weight of low density polyethylene (LDPE) resin, 20 to 83% by weight of linear low density polyethylene (LLDPE) resin, 3 to 33% by weight of metallocene linear low density polyethylene (mLLDPE) resin, medium density Polyethylene (MDPE) resin contains 3 to 30% by weight, high density polyethylene (HDPE) resin contains 3 to 12% by weight, anti-blocking agent (ab) 0.5 to 1.5% by weight, antistatic agent (as) 0.5 to 1.5% by weight So; It is composed of a triple polyethylene-based heat-shrinkable film with a shrinkage of 67 to 82% in the longitudinal direction (MD) and 4 to 53% in the transverse direction (TD).

The prior art triple polyethylene-based heat-shrinkable film has a problem in that the freshness of the package cannot be maintained for a long time because bacteria and viruses inhabit the inner and outer surfaces of the packaged film because the antibacterial agent is not provided inside the film.

The triple polyethylene-based heat-shrinkable film has a problem in that productivity decreases as the film becomes unnecessarily thick due to the multilayer.

The present invention is the above Conceived to solve the problems of the prior art, it is a single shrink film that is a mixture of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), but the composition ratio is specified to compensate for the disadvantages of the composition, and the master batch (MB) Antibacterial substance The antimicrobial copper powder and calcium absorbing moisture due to the fine condensation of the antibacterial copper powder are mixed to wrap the food by shrinkage, and the antibacterial activity of the antibacterial copper, that is, copper ions, is expressed on both sides of the film, thereby preventing the growth of microorganisms throughout the film. It is to provide a single antibacterial shrink film with good productivity and can maintain the freshness of packaged food for a long time by suppressing it.

Compensating for the disadvantages of stiffness, elongation, and transparency of linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) and using the advantages, linear low density polyethylene (LLDPE) 70.0 to 88.0 wt%, low density polyethylene (LDPE) 10.0 to 20.0 weight Percent shrinkage is given, and antimicrobial properties are given by mixing 2.0 to 10.0% by weight of an antimicrobial copper master batch (M/B: Master Batch) mixed with copper oxide (Copper Oxide) and calcium oxide (CaO). It is made with a single shrinking film that is always productive.

The present invention has the effect of simultaneously performing antimicrobial and contraction.

In addition, the present invention has an effect of preventing the growth of microorganisms throughout the film and maintaining the freshness of the packaged food for a long time because antibacterial copper is configured in a single-layer film, that is, copper ions are expressed on both sides of the film.

In addition, in the present invention, the composition ratio of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) is specified, so that uniform shrinkage occurs during integrated packaging, and wrinkles do not occur in the shrink film, and the longitudinal direction (MD) and the transverse direction ( TD) has the effect of shrinking to an appropriate balance.

In addition, the present invention has the effect of improving productivity and thinning the thickness due to the matrix having a single-layer structure.

In addition, the present invention has the effect that the antibacterial copper is a powder of copper oxide, so that the distribution in the matrix is good and the antibacterial activity is relatively evenly expressed.

Figure 1: A graph of the results of a comparative experiment in an American hospital.
Figure 2: Enlarged photograph of the present invention antibacterial copper 10,000 times.
Figure 3: Antibacterial test report of the present invention single antibacterial shrink film.
Figure 4: Antibacterial test results for each test item of the antibacterial test report of the present invention single antibacterial shrink film.
Figure 5: A photograph of the results of an antibacterial test of E. Coli conducted by the Korea Institute of Chemical Convergence Testing (KTR) for the single antibacterial shrinkage film of the present invention.
Figure 6: A photograph of the results of the antibacterial test of S. aureus conducted by the Korea Institute of Chemical Convergence Testing (KTR) for the single antibacterial shrinkage film of the present invention.
Figure 7: A photograph of the results of the antibacterial test of P. aeruginosa conducted by the Korea Institute of Chemical Convergence Testing (KTR) for the single antibacterial shrinkage film of the present invention.
Figure 8: A photograph of the results of the antimicrobial test of K. pneumoniae conducted by the Korea Institute of Chemical Convergence Testing (KTR) for the single antibacterial shrinkage film of the present invention.

Hereinafter, a preferred embodiment of the single antibacterial shrink film of the present invention will be described with reference to the accompanying drawings.

Polyethylene (PE: Polyethylene) is ethylene that divides crude oil from petroleum, separates the naphtha part (outflow part from 100 to 200℃) and decomposes it to fractionate about 25%. It is made by polymerization, and is composed of the following molecular structural formula, and there are some side chains, and the less the side chain, the higher the density and the higher the density, the stronger the strength.

CH2=CH2→... -CH2-CH2-CH2-CH2-...

In general, polyethylene (PE) has a difference in density depending on the polymerization method, and depending on the plastic density, VLDPE (Very Low Density Polyethylene), Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE: Linear) Low Density Polyethylene), Medium Density Polyethylene (MDPE), High Density Polyethylene (HDPE), Metallocene-catalyzed Linear Low Density Polyethylene (mLLDPE), Crosslinked Polyethylene (XLPE: Cross) Linking Polyethylene).

The low-density polyethylene (LDPE) polymerization is carried out under high pressure, whereas the linear low-density polyethylene (LLDPE) is also called low-pressure polyethylene because polymerization is carried out under a lower pressure using a catalyst, and is more rigid than low-density polyethylene (LDPE). It is also called hard polyethylene because of its high level.

The low-density polyethylene (LDPE) is strong because it has a low melting point (Tm: Melting point) of 105~115℃, but its tensile strength is not strong, so it has excellent workability, flexibility, and transparency, and the vicat softening point is 80~90℃. It cannot maintain its physical properties at high temperatures, and it compensates for weak heat resistance through a crosslinking method.

On the other hand, the linear low-density polyethylene (LLDPE) has a relatively high melting point of 110 to 125°C, so that it exhibits different crystallization behavior from that of low-density polyethylene (LDPE), so it has stronger physical properties than low-density polyethylene (LDPE) as well as low-density polyethylene. It is known that it is not compatible with (LDPE), but linear low density polyethylene (LLDPE) does not have a large difference in melting point and crystallization temperature, so if the cooling rate is fast, phase separation does not occur from each other even in the solid state.

One of the advantages of the low density polyethylene (LDPE) over linear low density polyethylene (LLDPE) is its viscous behavior in a molten state, high melt tension, and high viscosity at a low shear rate compared to linear low density polyethylene (LLDPE). Show.

In addition, since the low-density polyethylene (LDPE) has more long-chain branches than the linear low-density polyethylene (LLDPE), the melt tension is relatively high, so it has the stability of the bubble when extruding the blown film, and the viscosity change according to the temperature change due to the large activation energy Is big.

The low-density polyethylene (LDPE) and the linear low-density polyethylene (LLDPE) are both low-density due to the large number of side chains, but the low-density polyethylene (LDPE) has a network structure, whereas the linear low-density polyethylene (LLDPE) is linear.

The linear low-density polyethylene (LLDPE) has not as many side branches as low-density polyethylene (LDPE), but in terms of strength, it is higher than that of low-density polyethylene (LDPE), but its elongation is about 30% higher than that of low-density polyethylene (LDPE), and other characteristics are similar to that of low-density polyethylene (LDPE). Do.

The present invention uses the characteristics of antibacterial copper, linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) to form a single base layer, but shrinks and retains antimicrobial properties, such as food packaging, such as beverage PET bottles and beverage cans. Provides a resin composition of a polyethylene (PE)-based heat-shrinkable film having a sufficient shrinkage rate so that it can be packaged in bundles by integrated packaging of several pieces, but it can suppress the growth of microorganisms on the surface of packages and films and maintain the freshness of packaged foods for a long time. The productivity is good and the thickness becomes thin.

The present invention is mixed with linear low density polyethylene (LLDPE) 70.0 to 88.0 wt%, low density polyethylene (LDPE) 10.0 to 20.0 wt%, and antimicrobial copper master batch (M/B: Master Batch) 2.0 to 10.0 wt%, preferably linear Low-density polyethylene (LLDPE) is 75.0 to 84.0% by weight, low-density polyethylene (LDPE) is 12.0 to 18.0% by weight, and antimicrobial copper master batch (M/B) is mixed at 4.0 to 7.0% by weight.

Current status of melted resin and density of polyethylene resin used in the present invention Resin name Melt index
(MI: g/10min) density
(g/cm3) Remark Linear Low Density Polyethylene (LLDPE) 0.7 to 1.0 0.910 ~ 0.925 Low density polyethylene (LDPE) 0.3 to 0.8 0.910 ~ 0.925

The melt index was measured at 190° C. and 2.16 kg under the conditions of ASTM D1238, and the density was measured in a Density Gradient Column by ASTM D1505 method.

For reference, as a result of self-investigation, the linear low density polyethylene (LLDPE) is molded and contracted to 0.017 to 0.04 mm/mm when the density is 0.910 to 0.925 g/cm2, and the density of low density polyethylene (LDPE) is 0.910 to 0.925 g/cm2. In this case, it was molded and shrunk to 0.020 to 0.05 mm/mm. Using this mold shrinkage, linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) were appropriately mixed to specify the single antibacterial shrinking film of the present invention.

The melt index of the linear low-density polyethylene (LLDPE) is preferably 0.7 to 1.0 g/10 minutes, and if the melt index is 0.7 g/10 minutes or less, uniform shrinkage cannot be obtained, and if the melt index is 1.0 g/10 minutes or more, high temperature during blending Is required, and the density of linear low density polyethylene (LLDPE) is preferably 0.910 to 0.925 g/cm 3, and if the density is 0.910 g/cm 3 or less, excessive stretching causes problems in processing, and if it is 0.925 g/cm 3 or more, elasticity decreases. do.

It is preferable that the melt index of the low-density polyethylene (LDPE) is 0.3 to 0.8 g/10 minutes, and if the melt index is 0.3 g/10 minutes or less, processing is somewhat difficult, but the tensile strength is improved and the impact resistance is slightly lower if it is 0.8 g/10 minutes or more. However, transparency is improved, and the density of low-density polyethylene (LDPE) is preferably 0.910 to 0.925 g/cm 3, and if the density is 0.910 g/cm 3 or less, excessive stretching causes problems in processing, and if it is 0.925 g/cm 3 or more, the elasticity is Is lowered.

When the linear low-density polyethylene (LLDPE) is less than 70.0% by weight, the mechanical properties are adequate, but when the shrinkage in the longitudinal direction (MD) is insufficient, and when it exceeds 88.0% by weight, the mechanical properties are excellent, but the transverse direction (TD) is more than necessary. Contraction occurs.

When the low density polyethylene (LDPE) is less than 10.0% by weight, shrinkage and uniformity in the longitudinal direction (MD) is insufficient, and when it exceeds 20.0% by weight, the contraction and uniformity in the longitudinal direction (MD) is good, but mechanical properties This becomes lower.

The linear low-density polyethylene (LLDPE) has excellent mechanical properties, but since it has a short-sided chain, longitudinal (MD) shrinkage does not occur, and only transverse (TD) shrinkage occurs excessively, and low-density polyethylene (LDPE) is long-sided. Since the shrinkage ratio in the longitudinal direction (MD) and the transverse direction (TD) is balanced, the mechanical strength is weak and the frequency of hole generation during the shrinking process increases. LLDPE) and low-density polyethylene (LDPE) are properly blended so that the shrinkage rates in the longitudinal direction (MD) and the transverse direction (TD) are properly balanced, resulting in uniform shrinkage during integrated packaging and no wrinkles in the film.

The present invention has a single-layered structure of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), thereby improving productivity compared to a multi-layered structure.

The antibacterial copper master batch (MB: Master Batch) is a mixture of low-density polyethylene (LDPE) with antibacterial copper and calcium (Ca), and is 4.0~ for the total weight including linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) base. It is mixed at 7.0% by weight.

According to data from the US Environmental Protection Agency (EPA), in a comparative experiment on antibacterial performance of representative inorganic materials, 99.9% antibacterial activity was confirmed within 2 hours in copper alone, and more than 90% of super bacteria were reported to disappear within 30 minutes. In a comparative experiment in a hospital, no more than 90% pathogen/bacteria reduction super bacteria Methicillin Nesistant Staphylococcus Aureus (MRSA) and Vancomycin-resistant Enterococci (VRE) were detected on the surface of copper products. There are experimental results.

Briefly explaining the antimicrobial mechanism of copper: ① Bacteria recognizes copper ions on the surface of copper as essential nutrients, and absorbs copper ions into the body ⇒ Copper ions penetrate through bacterial cells ② Copper ions that enter the body Unstable disturbance of internal and external potential difference ⇒ Loss of vital nutrients and water inside cells ⇒ Cell membrane destruction ③ Copper ions attract external reactive oxygen species ⇒ Accelerate cell damage ④ Copper ions interfere with cellular respiration and metabolism ⇒ Genome and plasmids ( Plasmid) DNA degradation ⇒ Performed by blocking cell replication and self-proliferation.

The antimicrobial copper is the only touch surface material registered with the Environmental Protection Agency of the United States, and includes copper or a copper alloy having a copper content of 60% or more. The antimicrobial copper is a natural antibacterial property of copper itself, and is effective in preventing infectious infections such as cross-contamination, and exhibits uniform antibacterial activity regardless of humidity or particle size, and has excellent human safety and no resistance to bacteria.

The antimicrobial copper master batch (MB) affects the composition ratio of low-density polyethylene (LDPE), so if it is less than 4.0% by weight, shrinkage and uniformity in the longitudinal direction (MD) is insufficient, and if it exceeds 7.0% by weight, it has antibacterial properties. , Shrinkage and uniformity in the longitudinal direction (MD) are good, but mechanical properties are low.

The antimicrobial copper master batch (MB) is composed of 70.0 to 90% by weight of low density polyethylene (LDPE), 5.0 to 15.0% by weight of antibacterial copper, and 5.0 to 15.0% by weight of calcium (Ca), and is composed of antibacterial copper and calcium Ca) low density polyethylene (LDPE). ) Powder and sufficiently stirred and mixed, then melted, extruded, and cut into pellets.

When the antimicrobial copper in the master batch (M/B) is less than 5.0% by weight, the transparency is good, but when the antibacterial property is lowered and exceeds 15.0% by weight, the antibacterial property is good, but the transparency is lowered, and the calcium (Ca) is 5.0% by weight. If it is less than %, the antimicrobial copper is not completely dry. If it exceeds 15.0% by weight, condensation does not occur in the antibacterial copper, and one or more amounts are mixed.

When manufacturing the single antibacterial shrink film, low-density polyethylene (LDPE) chips, low-density polyethylene (LDPE) chips, and antibacterial copper master batch (MB) are simultaneously supplied to the hopper of the extruder, and the synthetic resin chips and the antibacterial are performed at 160-220℃ by a heater. After melting and melting the copper master batch (MB), the melt is extruded with a cylinder or extrusion screw to flow out to the blown film forming device, discharged from the blown film forming device to the outside, and blown air of the air ring by the blown film forming device. The tube-type single antibacterial shrink film, which is expanded by the inside of it, is cooled by the blown wind and rises into a cylindrical shape to become a tube-type single antibacterial shrink film. The tubular antibacterial shrink film is passed between a pair of rollers, and both sides are folded and folded. Finally, it is wound on a rotating reel to form a roll-shaped single antibacterial shrink film.

In the manufacture of the single antibacterial shrink film, antibacterial copper powder and calcium (Ca) powder are not sufficiently mixed with low-density polyethylene (LDPE) and low-density polyethylene (LDPE) resins. ) To prepare a master batch (MB) made of pellets of LDPE mixed with powder, and to prepare a single antibacterial shrink film, the low-density polyethylene (LDPE) chips and the low-density polyethylene (LDPE) chips were placed in the hopper. The same time Supply.

When preparing the single antibacterial shrink film, after mixing linear low density polyethylene (LLDPE) chips and low density polyethylene (LDPE) chips and master batch (MB) according to the composition ratio in advance, put them in the hopper of the extruder and melt them. Powder) and calcium (Ca) powder are evenly distributed in linear low density polyethylene (LLDPE) and low density polyethylene (LDPE).

The antimicrobial copper is composed of spherical powder of copper oxide (Copper Oxide: Cu2O) having an average diameter of 1 to 6 μm, and calcium Ca) is composed of spherical powder of calcium oxide (CaO: Calcium Oxide) having an average diameter of 1 to 6 μm. do.

When the average diameter of the copper oxide is less than 1 μm, an oxidation process is added to obtain a fine powder, which increases the manufacturing cost, and when the average diameter exceeds 6 μm, the antibacterial property is good, but the single antibacterial effect of the finished product The surface of the shrink film becomes rough, and when the average diameter of calcium oxide (CaO) is less than 1 μm, an oxidation process is added to obtain a fine powder, increasing the manufacturing cost, and when the average diameter exceeds 6 μm, antibacterial copper There is no condensation on the surface, but the surface of the single antibacterial shrink film of the finished product is rough.

When preparing the master batch (MB), chips of LDPE, copper oxide powder, and calcium oxide (CaO) powder were mixed with a rotary evaporate, a tumbler mixer, and a super mixer ( Super mixer), Hensxhel mixer, etc., and when stirred for a certain period of time, low density polyethylene (LDPE) chips, antibacterial copper powder, and calcium (Ca) powder are mixed.

The reason why the antimicrobial copper and calcium (Ca) are used as oxides is that the oxide is obtained by heating or oxidizing, that is, it is obtained by heating and vaporizing a metal or substance and burning it with air or burning it. This is because is fine and the particle size is relatively even.

The calcium oxide (CaO: Calcium Oxide): a compound of oxygen and calcium. Lime or quicklime is called lime or quicklime. When left in the air as white crystals, it absorbs moisture and carbon dioxide and decomposes into calcium hydroxide (slaked lime) and calcium carbonate. It is mass-produced through pyrolysis by heating limestone, calcium or calcium carbonate above about 900℃. It is widely used for various purposes such as, cement and bleach, but it is harmful to the human body because it has strong alkalinity and has a specific gravity of 3.0-3.4.

The antimicrobial copper master batch (M/B) is The distribution of linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) within the matrix is good, so that antibacterial copper and calcium (Ca) are distributed relatively evenly, so that the antibacterial activity of antibacterial copper, that is, copper ions, is expressed on both sides of the film and becomes spherical. As a result, the surface area per unit volume is large, so that antibacterial activity is expressed, and calcium (Ca) absorbs moisture and condensation does not occur in the antibacterial copper.

In order to constantly control the content of antibacterial copper and calcium (Ca) for the evaluation of the present invention, the input rate of low-density polyethylene (LDPE) chips and copper oxide and calcium oxide (CaO) was measured in three feeders. After proceeding, the low-density polyethylene (LDPE) chip has a melt index of 0.5 (MI: g/10min) and a density of 0.920g/cm3, low-density polyethylene (LDPE), an average diameter of 3 to 5㎛ spherical copper oxide) and an average diameter A master batch (M/B) was prepared using 3 to 5 μm spherical calcium oxide (CaO).

The low-density polyethylene (LDPE) chip, copper oxide, and calcium oxide (CaO) are supplied at a temperature of 108 to 111°C, and the feed rate (Hz) and screw rotation speed (rpm) are 1.0 Hz, 480 rpm, and copper oxide. And calcium oxide (CaO) are put into a simultaneous rotary three-screw extruder under conditions of 0.5 Hz and 130 rpm, respectively, and then the extrudate from the screw is pelletized using a pelletizer (speed of 4.3 Hz), and the master batch (M/B) Was manufactured.

Linear low density polyethylene (LLDPE) the master batch for the antibacterial film prepared above A single antibacterial shrink film having a thickness of 0.04 to 0.06 mm was prepared by mixing pellets and low density polyethylene (LDPE) pellets, and separate test pieces having different thicknesses were prepared for the impact strength test.

To analyze the content of linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), copper oxide and calcium oxide (CaO) in the manufactured single antibacterial shrink film, using the Q500 TA equipment, 25℃ at a rate of 10℃/min in a nitrogen atmosphere. Thermogravimetric analysis (TGA) was performed from to 700°C.

The composition for the single antibacterial shrink film of the present invention is shown in Table 2 below.

Composition status (% by weight) division Ref Example 1 Example 2 Example 3 Example 4 Example 5 LLDPE - 86.1 82.4 77.8 75.6 72.1 LDPE - 9.2 9.6 10.0 10.3 11.1 Antibacterial copper - 2.2 4.1 5.9 7.1 8.5 calcium - 2.5 3.9 6.3 7,0 8.3

In the present invention, the physical properties and antibacterial tests for the single antibacterial shrink film (Examples 1 to 5) were evaluated by the following method.

1. Physical property test

end. Shrinkage rate

It was carried out by the test method specified on the KS A1511 shrink packaging film, and from the prepared single antibacterial shrink film, a 100mm*100mm square sample parallel to the MD of one side film was collected, and an ethylene glycol solution in a thermostatic bath at 120℃ After immersing in a bathtub of 20 seconds, it was taken out, cooled at room temperature for 5 seconds, and the lengths in the longitudinal direction (MD) and the transverse direction (TD) were measured, and the shrinkage rate was calculated by the following equation.

Shrinkage (%) = 100-(Lo-Lt)/Lo

Lo: Length before contraction.

Lt: length after contraction.

I. Turbidity (Haze)

The haze of the film was measured by the ASTM D 1004 method.

All. Impact strength

Izod impact strength was measured using an impact tester (Model 863, Ueshima Seisakusho Co., Ltd.) according to the JIS K7110 standard on a rectangular test piece (63 mm x 12 mm x 5 mm).

la. Film appearance after shrinkage

After making the shrink film so that it can be used as a label on the shoulder of a 1.5 PET bottle container, it was placed in the container, and then contracted in an air oven at 150°C for 30 seconds, and the appearance condition was repeated 10 times to determine the average number of defects. If the number is less than 10, it is marked as good (0), if it is less than 5 (△), and if it exceeds 5, it is marked as bad (x). In addition, the number of defects in appearance was determined by labels for shrinkage, wrinkles, curling of the upper and lower ends, and distortion of the print shape.

The Ref is a heat-shrinkable film sold in the general market and used in integrated packaging PET beverage bottles, and the present invention is the shrinkage rate, friction coefficient, turbidity, impact strength, and appearance after shrinkage by mixing the composition according to Examples 1 to 5 The state was evaluated by the above evaluation method.

The results of the physical property test of Ref to Example 5 are shown in Table 3 below.

division Ref Example 1 Example 2 Example 3 Example 4 Example 5 Shrinkage rate
(%) Longitudinal 69 74 73 73 73 72 Transverse 19 23 25 26 26 23 Haze value (%) 58.7 67.6 89.9 90.5 93.8 94.7 Impact strength (J/m) 61 68 70 73 78 80 Film appearance after shrinkage Good Good Good Good Good Good

From the above evaluation results, the present invention has a longitudinal contraction rate of 72 to 74%, a transverse contraction rate of 23 to 26%, an impact strength of 68 to 80 (J/m), and the longitudinal direction (MD) and the transverse direction (TD) are appropriate. The shrinkage was balanced in a balanced manner and no wrinkles occurred in the shrinking film, so it was generally better than the Ref for evaluation.

2. Antibacterial test

3 is an antibacterial test report conducted by the Korea Institute of Chemical Convergence Testing (KTR) for a single antibacterial shrink film of the present invention, and FIG. 4 is a report of an antibacterial test conducted by the Korea Institute of Chemical Convergence Testing (KTR) for a single antibacterial shrink film of the present invention. The results of the antibacterial test for each test item are shown, and FIG. 5 is a photograph of the test results of the antimicrobial test conducted by the Korea Research Institute of Chemical Convergence (KTR) on the single antibacterial shrink film of the present invention. E. Coli unprocessed test piece after 24 hours, the right photo is an antibacterial processed test piece of E. Coli after 24 hours, and FIG. 6 is an antibacterial test conducted by the Korea Chemical Convergence Testing Institute (KTR) for the single antibacterial shrink film of the present invention. As a result of the test, the photo on the left is an unprocessed test piece of S. aureus after 24 hours, and the photo on the right is an antimicrobial processed test piece of S. aureus after 24 hours, and FIG. 7 is the Korea Chemical Convergence Test Institute for the single antibacterial shrinkage film of the present invention ( KTR) is a photo of the test result of the antibacterial test conducted by the left photo is an unprocessed test piece of P. aeruginosa after 24 hours, and the photo on the right is an antibacterial processed test piece of P. aeruginosa after 24 hours. On the other hand, the photo of the test result of the antibacterial test conducted by the Korea Institute of Chemical Convergence Testing (KTR). The left photo is an unprocessed test piece of K. pneumoniae after 24 hours, and the photo on the right is an antibacterial processed test piece of K. pneumoniae after 24 hours.

end. In the antibacterial test, Example 3 was used as a sample, and the antibacterial effect of the sample was evaluated in accordance with the test method of JIS Z 2801:2012 in the Korea Institute of Chemical Convergence Testing (KTR). Test monarchs were E. coli (Gram negative), S. aureus (Gram positive), K. pneumoniae (Gram negative) and P. aeruginosa (Gram negative), and the test strain was inoculated into the specimen and 35±1℃, After incubating for 24±1 hours at a relative humidity of 90% or more, the number of viable cells was measured by recovering the bacteria from each specimen, and after 24 hours, the antibacterial activity value was calculated by comparing with the number of control viable cells of the unprocessed specimen.

I. Pre-cultivation of test bacteria and preparation of test bacteria solution

Inoculate the strain on the slope medium from the preserved strain, pre-incubate the test strain for 16-20 hours at 35±1℃, and add 2.5-10 CFU/mL to the nutrient broth (1/500 NB) diluted 500 times. It was suspended as possible and used as an inoculum solution.

All. Inoculation and culture of test bacteria solution

Inoculate 0.4 mL of the prepared test bacteria solution on the test pieces of each specimen placed in the Petri dish, and cover the film to spread the test bacteria solution evenly over each specimen. Close the Petri dish cap and under conditions of 35±1°C and 90% relative humidity. Incubated for 24±1 hours.

la. Collection and measurement of test bacteria

Using 10 mL of SCD broth, bacteria were recovered from the unprocessed specimen immediately after inoculation, the antibacterial specimen after 24 hours incubation, and the unprocessed specimen after 24 hours incubation, and the recovered bacteria solution was 35±1°C using a plate count agar. After incubation for 40 to 48 hours, the number of viable cells was measured.

hemp. Calculate the result

(1) Count viable cells

N = (C × D × V)A

N: number of viable cells (per test piece)

C: Number of colonies (average value of the number of colonies of two)

D: Dilution factor (dilution factor of diluent)

V: The amount of the SCDLP medium used for bacterial solution recovery (mL)

A: Surface area of coating film (㎠)

(2) Calculation of antibacterial activity

R = (U _t- U _O ) _-( A _t- U _O ) = U _t- A _t

R: Antibacterial activity value

U _t : Average log value of viable cell count after 24 hours of unprocessed specimen

U _O : Average log value of the number of viable cells immediately after inoculation of the unprocessed specimen

A _t : Average log value of the number of viable cells after 24 hours of the antibacterial processed test piece

bar. Test result

(1) The results of the antibacterial test for E. coli are shown in Table 4 below.

Number of repetitions Early Unprocessed test piece (after 24 hours) Antibacterial processed test piece (after 24 hours) CFU/㎠ log value CFU/㎠ log value CFU/㎠ log value One 1.4 × 10 ⁴ 4.15 4.1 × 10 ⁴ 4.61 <0.63 -0.20 2 1.4 × 10 ⁴ 4.15 4.7 × 10 ⁴ 4.67 <0.63 -0.20 3 1.4 × 10 ⁴ 4.15 4.9 × 10 ⁴ 4.69 <0.63 -0.20

The average log value of the number of viable cells immediately after inoculation of the unprocessed test piece (U _O ) is 4.1, the average of the log value of the number of viable cells after 24 hours of the unprocessed test piece (U _t ) is 4.6, and the number of viable cells after 24 hours of the unprocessed test piece The average log value (A _t ) is -0.2 and the antimicrobial activity value (R) is 4.8, indicating that the single antibacterial shrink film of the present invention has antibacterial properties against E. coli bacteria.

(2) The results of the antibacterial test for S. aureus are shown in Table 5 below.

Number of repetitions Early Unprocessed test piece (after 24 hours) Antibacterial processed test piece (after 24 hours) CFU/㎠ log value CFU/㎠ log value CFU/㎠ log value One 2.0 × 10 ⁴ 4.30 7.8 × 10 ⁴ 4.89 <0.63 -0.20 2 2,0 × 10 ⁴ 4.32 7.9 × 10 ⁴ 4.90 <0.63 -0.20 3 1.9 × 10 ⁴ 4.28 8.3 × 10 ⁴ 4.92 <0.63 -0.20

The average log value of the number of viable cells immediately after inoculation of the unprocessed test piece (U _O ) is 4.3, the average of the log value of the number of viable cells after 24 hours of the unprocessed test piece (U _t ) is 4.9, the number of viable cells after 24 hours of the unprocessed test piece The average log value (A _t ) is -0.2 and the antimicrobial activity value (R) is 5.1, so that the single antibacterial shrink film of the present invention has antimicrobial properties against S. aureus bacteria.

(3) The results of the antibacterial test for P. aeruginosa are shown in Table 6 below.

Number of repetitions Early Unprocessed test piece (after 24 hours) Antibacterial processed test piece (after 24 hours) CFU/㎠ log value CFU/㎠ log value CFU/㎠ log value One 2.0 × 10 ⁴ 4.30 2.4 × 10 ⁵ 5.38 <0.63 -0.20 2 2,1 × 10 ⁴ 4.32 2,8 × 10 ⁵ 5.45 <0.63 -0.20 3 1.9 × 10 ⁴ 4.28 3.0 × 10 ⁵ 5.48 <0.63 -0.20

The average log value of the number of viable cells immediately after inoculation of the unprocessed test piece (U _O ) is 4.3, the average of the log value of the number of viable cells after 24 hours of the unprocessed test piece (U _t ) is 5.4, the number of viable cells after 24 hours of the unprocessed test piece The average log value (A _t ) is -0.2, and the antimicrobial activity value (R) is 5.6, so that the single antibacterial shrink film of the present invention has antibacterial properties against P. aeruginosa bacteria.

(4) The results of the antibacterial test for K. pneumoniae are shown in Table 7 below.

Number of repetitions Early Unprocessed test piece (after 24 hours) Antibacterial processed test piece (after 24 hours) CFU/㎠ log value CFU/㎠ log value CFU/㎠ log value One 2.0 × 10 ⁴ 4.30 2.1 × 10 ⁵ 5.32 <0.63 -0.20 2 2,1 × 10 ⁴ 4.32 2,0 × 10 ⁵ 5.30 <0.63 -0.20 3 2.2 × 10 ⁴ 4.34 2.4 × 10 ⁵ 5.38 <0.63 -0.20

The average log value of the number of viable cells immediately after inoculation of the unprocessed test piece (U _O ) is 4.3, the average of the log value of the number of viable cells after 24 hours of the unprocessed test piece (U _t ) is 5.3, the number of viable cells after 24 hours of the unprocessed test piece The average log value (A _t ) is -0.2 and the antimicrobial activity value (R) is 5.5, so that the single antibacterial shrink film of the present invention has antibacterial properties against K. pneumoniae bacteria.

(5) The overall results of the antibacterial test are shown in Table 8 below.

Test strain U _O (log) U _t (log) A _t (log) R(log) E. coli 4.1 4,6 -0.2 4.8 S. aureus 4.3 4.9 -0.2 5.1 P. aeruginosa 4.3 5,4 -0.2 5.6 K. pneumoniae 4.3 5.3 -0.2 5.5

As a result of the test, the antimicrobial activity (R) was 4.8 in E. coli, 5.1 in S. aureus, 5.6 in P. aeruginosa, and 5.5 in K. pneumoniae, so that the single antimicrobial shrinking film of the present invention has excellent antibacterial performance.

The terms or words used in the specification and claims of the present invention are not limited to a conventional or dictionary meaning, and the inventor can appropriately define the concept of terms in order to describe his own invention in the best way. Based on the point, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention.

Therefore, since the embodiments described in the detailed description of the present invention and the configuration shown in the drawings are only the most preferred embodiment of the present invention, the scope of the present invention is limited to the described embodiments and should not be determined, but at the time of filing of the present invention. It should be understood that variations are possible or may exist, and should be determined by the claims and equivalents.

Claims (5)

delete In a single antibacterial shrink film,
The single antibacterial shrinkage film includes 75.0 to 84.0 wt% of linear low density polyethylene (LLDPE), 12.0 to 18.0 wt% of low density polyethylene (LDPE), 70.0 to 90 wt% of low density polyethylene (LDPE) and 5.0 to 15.0 wt% of antibacterial copper. An antimicrobial copper master batch (M/B: Master Batch) mixed with 5.0 to 15.0% by weight of calcium (Ca) is mixed at 4.0 to 7.0% by weight, the longitudinal shrinkage is 72-74%, and the transverse shrinkage is 23-26 Single antibacterial shrink film, characterized in that %.
delete The method of claim 2,
The antibacterial copper is a single antibacterial shrink film, characterized in that the average diameter of 1 ~ 6㎛ spherical copper oxide (Copper Oxide).
The method of claim 4,
The calcium (Ca) is a single antimicrobial shrinking film, characterized in that the average diameter of 1 ~ 6㎛ spherical calcium oxide (CaO).

Images