KR101072884B1 - Photocatalyst coating composition comprising nano titanium dioxide, manufacturing method thereof, packaging film for soybean sprouts and manufacturing method thereof - Google Patents

Abstract

Provided are a photocatalyst coating composition comprising nano titanium dioxide, a method for preparing the same, a film for packaging bean sprouts, and a method for preparing the same.

The photocatalytic coating composition according to the invention is characterized in that it comprises nano titanium dioxide and a coating binder. The photocatalytic coating composition according to the present invention improves the coagulation phenomenon generated when coating nano titanium dioxide on a food packaging film, which is a problem of the prior art, so that the photocatalytic material titanium dioxide can be applied to a food packaging film, and The bean sprouts packaging film is produced by the method of directly mixing nano titanium dioxide with food packaging materials to alleviate the blue phenomena inevitably generated when packaging bean sprouts, and to improve the storage and distribution of bean sprouts by photolysis of off-flavor components. However, the production of food packaging films by coating nano titanium dioxide will provide significant industrial benefits to the food packaging sector by increasing the efficiency of the production process and overcoming the application limitations to applicable food packaging films.

Description

Photocatalyst coating composition comprising nano titanium dioxide, manufacturing method, packaging film for soybean sprouts and manufacturing method

The present invention relates to a photocatalyst coating composition comprising nano titanium dioxide, a method for manufacturing the same, a film for packaging bean sprouts, and a method for preparing the same, and more particularly, to nanoparticles having excellent photodegradability and UV blocking effect while maintaining transparency of the bean sprout packaging film. It relates to a photocatalyst coating composition comprising titanium dioxide, a method for preparing the same, a film for packaging bean sprouts, and a method for producing the same.

Soybean sprouts sprouted from soybeans are traditional Korean foods that have been used since the Goryeo Dynasty. The average daily intake of Korean adults (20g) is the second highest after Chinese cabbage and radish. The annual output is 650,000 tons and the production value is 400 billion won. Soybean sprouts can be grown in soil-free, short growing period of about 5 days, and can be grown year-round without the need for special facilities. In addition, the price is low, the consumption is gradually increasing worldwide. Soybean sprouts are known to have a high nutritional value, such as 300% more vitamin A and 500-600% higher vitamin C than soybean seeds. However, since soybeans, which are not just quantitative but quality, are given higher value in their functionality than any other crops, the safety of the product is required along with the development of higher functional varieties.

Agricultural products such as bean sprouts continue to breathe during distribution after harvest. Respiration is the action of carbohydrates in living organisms to produce carbon dioxide, water and energy. Under anaerobic conditions that lack oxygen, glucose is broken down into pyruvic acid and carbon dioxide is lost to acetaldehyde. This is then reduced, leading to anaerobic respiration, where ethanol is produced. A variety of metabolites resulting from anaerobic respiration have been reported as a cause of off-flavor occurring during the distribution of various horticultural products, such as bean sprouts and broccoli, which are distributed in packaging.

Distribution of bean sprouts was conventionally cultivated in a cultivation container and marketed as a cultivation container and sold to consumers. However, recently, harvested bean sprouts are washed and sorted, such as polyethylene (PE) or polypropylene (PP). It is packaged and sold in 300g to 500g units in transparent plastic film packaging. As the small package distribution of soybean sprouts increases, development of packaging materials for maintaining the freshness of the bean sprouts is required, but there is no conventional technique for integrated management of post-harvest management techniques such as pre-cooling, packaging, storage, and freshness maintenance of bean sprouts.

Polyethylene (PE), polypropylene (PP), cast polypropylene (CPP), and stretched polypropylene (OPP) are currently used as bean sprout packaging films, but bean sprout packaging such as film type, thickness, and punching ratio is still suitable for bean sprout packaging. Overall research on the situation is insufficient.

The bean sprouts packaging material currently on sale uses a transparent film so that consumers can check the quality of the contents. As a result, light penetrates and the cotyledon of green bean sprouts is recorded as described above, and odors are caused by anaerobic conditions inside the package. There is a problem. Qualitative and quantitative analysis of substances causing odor generated during distribution and research on bluing, such as quantitative measurement methods to evaluate the degree of sorghum phenomena during distribution and storage , The influence of temperature and gaseous environmental factors, odor removal method, etc. have not been studied.

Nanotechnology, meanwhile, is a technology that manipulates and controls the phenomena, structures, and elements of atoms and molecules by applying new physical, chemical, and optical properties that materials have at the nanometer (10 ^-9 m) level.

Nanotechnology controlled at the ultra-fine level is widely used as a key core technology in all industries, including the fine chemical industry, the electronic information business, the environmental industry, the biotechnology industry, the food and pharmaceutical industry, and the automotive industry. In particular, the application of nanotechnology, such as nanomaterials, ultra-fine processing to packaging is called nano-packaging. Among the packaging fields, the food packaging field has a high potential for nanopackaging applications, and one of the nanopackaging technologies applied is polymer nanocomposites.

Nanocomposite refers to a composite material in which a polymer for packaging material is reinforced with nanometer-sized particles having a plate, fibrous or particulate structure. The nanocomposite formed by uniformly dispersing nanoparticles has the characteristics of increasing physical strength, unusual thermal and optical properties, and decreasing gas permeability compared to pure polymers by adding less than 5% of nanomaterials. It is known as a packaging material having excellent physical properties.

Currently, interest in titanium dioxide (TiO ₂ ) among nanomaterials used in nanocomposites has increased. In particular, interest in titanium dioxide as a photocatalyst is increasing. Photocatalyst is a compound word of light (Photo = Light) + catalyst. When nano-sized particles receive light, they generate strong oxides (OH radicals, superoxides) on the surface of the particles, decomposing harmful substances in the air into harmless substances (H ₂ O, CO ₂ , O ₂ ).

As such a photocatalyst, a semiconductor metal oxide or a sulfur compound is used. In addition to titanium dioxide (TiO ₂ ), materials currently being studied as photocatalysts include cadmium selenide (CdSe), zinc oxide (ZnO), cadmium sulfide (CdS), strontium titanate (SrTiO ₃ ; perovskite), There are various substances such as potassium niobate (KNbO ₃ ), but since they are water-soluble substances or heavy metal substances that are easily dissolved in water, they are harmful to the human body and are physically and chemically unstable. Titanium dioxide, however, is harmless to the human body as a food additive, is a chemically and physically stable substance, and its photoactivity is superior to other compounds.

Titanium dioxide used in the photocatalytic reaction is generally rutile (Rutile) and anatase (Anatase) have a different crystal structure.

Rutile is the most common of the two crystalline forms, the same form as tin dioxide (SnO ₂ ) and has a slightly wide rectangular structure. It is a white solid and is mainly used as a raw material for pigments and paints. Rutile has a band gap energy of about 3.02 eV and consists of a line contact structure between crystals.

Anatase is the most widely used crystal structure as a photocatalyst because it has a larger band gap energy (about 3.2 eV) than rutile. It has a vertically elongated rectangular shape and is automatically converted into a rutile structure at a high temperature of about 915 ° C. The crystal structure is almost the same as that of rutile in hardness, density, color, gloss, and a point contact structure between crystals.

In terms of the efficiency of photoreaction, anatase has a slightly higher band energy (3.23 eV and 3.02 eV) than rutile, so anatase is often used as a photocatalyst material.

1 is a schematic diagram showing photoexitation inside titanium dioxide.

Referring to FIG. 1, the photocatalyst titanium dioxide semiconductor has an empty energy region, so that the conduction band from the conduction band to the valence band of the region is called a band gap. When the semiconductor absorbs energy above the band gap, electrons are excited to cause an electron transition from the valence band to the conduction band, and the generated electron and hole pairs move to the semiconductor surface as shown in FIG. 1.

The electron-hole pair thus formed is subjected to one of the following processes.

1) Oxidation & Reduction → Reactant and Photochemical Reaction

2) Surface Recombination → Electron / Hole pair recombine itself

3) Volume Recombination → Reaction that decomposes catalyst by reacting with active catalyst separated by electron / hole, not catalyst

Since most electron-hole pairs recombine themselves rather than participate in actual reactions, the longer the semiconductor material is separated into electrons / holes, the higher the probability of reaction.

Photoexcitation of such semiconductors is a step in which light energy is converted into electricity or chemical energy. Like semiconductors, metals can absorb light and be excited, but the recombination of electrons and holes is so fast that there is no time for the absorbed light energy to be converted into other forms of energy. Therefore, when electrons and holes recombine, extra energy is emitted back to light or converted into thermal energy of lattice vibration. The electrons and holes thus formed participate in oxidation and reduction reactions, respectively.

Food packaging refers to a packaging technology that protects the value and status of foods in the distribution process and at the same time provides convenience and sales promotion.

If the packaging is not suitable, food is discolored under the influence of moisture, oxygen and light during distribution, various microorganisms grow, and fat and important vitamins are oxidized, resulting in the destruction of properties, odor, and rapid decay. Therefore, suitable food packaging technology to prevent this is indispensable in the food industry.

The photodegradation and UV-protection properties of the above-described titanium dioxide (TiO ₂ ) to suppress the blue phenomena of soybean sprout cotyledon and the off-flavor odor in the packaging material and to increase the shelf life of soybean sprouts. There is a need for the development of endowed functional packaging.

However, titanium dioxide used as the photocatalyst is excellent UV protection unlike other materials. Despite the VOCs and antimicrobial effects, it is difficult to manufacture a coroutine solution, that is, a photocatalyst coating composition, which cannot be used by a packaging company, and thus there is a problem in commercialization.

One example of the prior art relates to a food preservation bag including a photocatalyst, but not a coating method, but a method of impregnating a photocatalyst in a synthetic resin film. When using a nanoscale photocatalyst, a nano-sized photocatalyst in a synthetic film is used. There is a limit to evenly distributed, there is a difficult handling in production.

Therefore, the first problem to be solved by the present invention is to provide a photocatalyst coating composition that can effectively reduce the bluening phenomenon and off-flavor components of bean sprouts.

The second problem to be solved by the present invention is to provide a bean sprouts packaging film coated with the photocatalyst coating composition.

The third problem to be solved by the present invention is to provide a method for producing the photocatalyst coating composition.

The fourth problem to be solved by the present invention is to provide a method for producing a film for packaging bean sprouts coated with the photocatalyst coating composition.

In order to achieve the first object of the present invention,

It provides a photocatalyst coating composition comprising nano titanium dioxide and a coating binder.

According to one embodiment of the present invention, the average particle size of the nano titanium dioxide may be 10 ~ 30nm.

According to another embodiment of the present invention, the coating binder may be any one selected from polyurethane or polyvinyl butyral-cellulose.

According to another embodiment of the present invention, the content of the nano titanium dioxide may be 3 to 5% by volume and the content of the binder may be 3 to 5% by volume.

In order to achieve the second object of the present invention,

The photocatalyst coating composition provides a film for food packaging, characterized in that the coating on one or both sides of the synthetic resin film.

According to one embodiment of the invention, the synthetic resin film may be any one or more selected from the group consisting of polyethylene (PE), polypropylene (PP), cast polypropylene (CPP) and stretched polypropylene (OPP).

The present invention to achieve the third object,

It provides a method for producing a photocatalyst coating composition comprising the step of mixing nano titanium dioxide and a binder.

According to one embodiment of the present invention, the crystal structure of the nano titanium dioxide is an anatase crystal structure, the average particle size may be 10 ~ 30nm.

According to another exemplary embodiment of the present invention, the coating binder may be any one selected from polyurethane or polyvinyl butyral-cellulose.

According to another embodiment of the present invention, the content of the nano titanium dioxide may be 3 to 5% by volume and the content of the binder may be 3 to 5% by volume.

In order to achieve the fourth object of the present invention,

It provides a method for producing a food packaging material comprising coating the photocatalyst coating composition on one or both sides of the synthetic resin film.

According to an embodiment of the present invention, the coating may be to use a bar coater.

According to another embodiment of the present invention, the linear velocity of the bar coater may be 50 ~ 100m / s.

The photocatalytic coating composition according to the present invention improves the coagulation phenomenon generated when coating nano titanium dioxide on a food packaging film, which is a problem of the prior art, so that it is possible to effectively coat titanium dioxide on a food packaging film, which is harmless to a human body, which is a representative photocatalyst material. Titanium dioxide can be applied to food packaging films. The bean sprouts packaging film according to the present invention is a transparent food packaging film, so that the greening phenomenon and odor component inevitably occurs when packaging bean sprouts packaging film coated with a photocatalytic coating composition containing titanium dioxide to blue The food packaging film is manufactured by coating nano-titanium dioxide rather than by directly mixing nano-titanium dioxide with food packaging materials to improve the storage and distribution of bean sprouts by alleviating the phenomenon and photolyzing the odor components. This will provide significant industrial benefits to the food packaging sector by increasing the efficiency of the production process and overcoming the limitations of application to applicable food packaging films.

The present invention is coated with a colloidal nano TiO ₂ on a transparent film currently used for bean sprouts packaging foods that can see the decomposition effect of volatile organic compounds (VOCs) due to the UV blocking effect and photocatalytic effect of TiO ₂ itself It is about packaging materials. The TiO ₂ UV blocking effect can prevent the bluening phenomenon of the cotyledon part, and by removing the odor component and antibacterial due to the photocatalytic effect can prevent the problems occurring during distribution, storage of bean sprouts.

The photocatalyst coating composition according to the present invention comprises nano titanium dioxide and a coating binder. The nano titanium dioxide is preferably any one selected from anatase titanium dioxide or rutile titanium dioxide, and more preferably anatase structure of titanium dioxide having a higher photocatalytic activity, but the structure of the titanium dioxide is not particularly limited. Does not.

According to the present invention, the average particle size of the titanium dioxide is preferably 10 to 30 nm, and the reason is that when the average particle size of the titanium dioxide is 10 nm or less, the specific surface area is increased to disperse when mixed with the binder. This is because there is a problem and the specific surface area is reduced in the case of more than 30nm, the photocatalytic efficiency is reduced due to mixing with the binder.

According to the present invention, the coating binder is preferably used any one selected from polyurethane (PU) or polyvinyl butyral-cellulose (PVB), the coating binder is harmless to food packaging The binder is not particularly limited and may be selected and used according to the substrate to which the photocatalyst coating composition is applied.

The PU is currently the binder most commonly used for film coating, and the PVB is a binder having a UV blocking effect currently used as a binder for vehicle glass.

Referring to the following surface analysis test example of the nano-TiO ₂ coating film to test the compatibility of the binder and TiO ₂ , the phenomenon of aggregation of the film surface is caused by the concentration difference between TiO ₂ and each binder PU and PVB. . Agglomeration occurs because TiO ₂ particles themselves are nano-sized, so the specific surface area increases and the attraction between each other increases, causing agglomeration.

In addition, the difference in surface analysis results not only in the concentration difference of TiO ₂ but also in the type of binder. When the concentration of the coating binder was 3%, the PU showed a more uniform surface dispersion than the PVB. When the concentration of the coating binder was 5%, the PVB covered the TiO ₂ surface and dispersed well as the concentration of the coating binder increased. Not done.

As a result, it can be seen that the coating binder is better in terms of coating than PVB when the TiO ₂ film is coated.

Referring to the following test example analyzing the UV blocking ability of the nano TiO ₂ coating film, it can be seen that the binder itself affects the UV blocking ability in addition to the concentration difference of TiO ₂ . Therefore, since PVB is a UV-blocking binder, it is more preferable to use a PVB binder that can exert a synergy effect on UV blocking by using PVB having UV blocking ability in order to correspond to a region blocked by TiO ₂ .

According to the above, it can be seen that PU is advantageous in terms of coating and PVB is advantageous in terms of UV protection. Therefore, the use of a binder mixed with PU and PVB may be considered. However, when the binder mixed with PU and PVB is used, discoloration occurs during drying due to chemical bonding between the two binders, and a characteristic smell is not preferable. .

The nano photocatalyst coating composition is characterized by comprising 3 to 5% by volume of nano titanium dioxide and 3 to 5% by volume of the binder.

The volume fraction of the nano-titanium dioxide is preferably 3 to 5% by volume, because the effect of the photocatalyst is inadequate when less than 3% by volume, and when the content exceeds 5% by volume, the viscosity of the coating composition is increased and the coating operation is performed. This is because the efficiency decreases.

The volume fraction of the binder is preferably 3 to 5% by volume, because if the content is less than 3% by volume, the effect of the binder is insufficient, resulting in a drop in adhesive strength. This is because phase separation occurs when mixed with titanium dioxide.

Food packaging film according to the invention is characterized in that the photocatalyst coating composition is coated on one side or both sides of the synthetic resin film.

In the case of coating on one side of the food packaging film, the photocatalyst coating composition is coated only on one surface corresponding to the inside of the food packaging paper, but if necessary, the photocatalyst coating composition may be coated on both sides of the food packaging film.

The synthetic resin film is preferably at least one selected from the group consisting of polyethylene (PE), polypropylene (PP), cast polypropylene (CPP) and stretched polypropylene (OPP), and is particularly limited as long as it is transparent as a food packaging film. It doesn't work. The reason why the food packaging film should be transparent is that the consumer should visually observe the freshness of the contents.

Method for producing a photocatalyst coating composition of the present invention is characterized in that it comprises the step of mixing the nano titanium dioxide and the binder.

Hereinafter, the method for preparing the photocatalyst coating composition of the present invention will be described in more detail.

First, the nano-colloidal TiO ₂ in solid form is diluted with alcohol to dilute to the required concentration. Next, the binder is diluted with alcohol to the required concentration. TiO ₂ and the binder prepared as described above are dispersed using a particle disperser.

The nano titanium dioxide is preferably any one selected from titanium dioxide having an anatase structure or titanium dioxide having a rutile structure, and more preferably titanium dioxide having an anatase structure with greater photocatalytic activity.

The average particle size of the titanium dioxide is preferably 10 to 30 nm, and the reason is as described above.

According to the present invention, the coating binder is preferably used any one selected from polyurethane (PU) or polyvinyl butyral-cellulose (PVB), the coating binder is harmless to food packaging The binder is not particularly limited and may be selected and used according to the substrate to which the photocatalyst coating composition is applied.

The nano photocatalyst coating composition is characterized by comprising 3 to 5% by volume of nano titanium dioxide and 3 to 5% by volume of the binder. As such, the reason for limiting the range of the volume% of the nano titanium dioxide and the binder is as described above.

The method for producing a food packaging film according to the present invention includes the step of coating the photocatalyst coating composition on one side or both sides of the synthetic resin film.

In the case of coating on one side of the food packaging film, the photocatalyst coating composition is coated only on one surface corresponding to the inside of the food packaging paper, but if necessary, the photocatalyst coating composition may be coated on both sides of the food packaging film.

The synthetic resin film is preferably at least one selected from the group consisting of polyethylene (PE), polypropylene (PP), cast polypropylene (CPP) and stretched polypropylene (OPP), and is not particularly limited as long as it is transparent as a food packaging film. Do not. The reason why the food packaging film should be transparent is that the consumer should visually observe the freshness of the contents.

The coating step is preferably a bar coater, but is not particularly limited as long as it is a coating method commonly used in food packaging.

In one embodiment of the present invention, after fixing the synthetic resin film to the automatic coating machine, the prepared photocatalyst coating composition was applied to the film with a dropper and then coated at an appropriate speed using a bar coater (bar coater). The prepared film was placed in a dry oven, dried at a constant temperature and for a predetermined time, and then dried at room temperature for a predetermined time.

It is preferable that the linear velocity of the bar coater is 50 to 100 m / s. The reason is that when the linear velocity is less than 20 m / s, the phenomenon of TiO ₂ agglomeration occurs in the middle of the film, and even when the linear velocity exceeds 100 m / s. This is because TiO ₂ agglomeration occurs in the middle of the film.

Hereinafter, the present invention will be described in more detail with reference to Examples and Test Examples. However, these Examples and Test Examples are intended to illustrate the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these Examples and Test Examples. .

Example

Material preparation

Nano Colloidal TiO ₂

In one embodiment of the present invention, 10% of the nano-colloidal TiO ₂ of the solid content dispersed in water and 2-methoxy ethyl alcohol was used, the nano colloidal TiO ₂ is nano (NTS-20-04, Korea) ) And the average particle size of the nano TiO ₂ was 20 to 30nm.

Binder

The binder was 10% solids of PU and 28% solids of PVB. The PU was purchased from Sunggo Chemical (Korea), and the PVB was purchased from Chengdu Chemical (Korea).

Photocatalyst  Solvents for Diluting Coating Compositions

To dilute the nano TiO ₂ and the binder, ethyl alcohol having a purity of 99.9% was purchased from Duksan Co., Ltd.

Packing material

The packaging material used in the embodiment of the present invention used a stretched polypropylene (oriented poly propylene, OPP) film having a thickness of 30㎛ widely used as bean sprouts packaging material. The OPP film was purchased from Ju Won P & B (Korea).

Bean sprouts

Bean sprouts were purchased from Pulmuone Co., Ltd., and the average length of the bean sprouts was 12 ± 0.5 cm and the weight was 1.5 ± 0.4 g.

Methylene blue ( Methylene Blue )

Methylene blue (C ₁₆ H ₁₈ N ₃ SCl ₃ H ₂ O) used in the photolysis test was purchased from Samcheon (Korea), and the solvent used in preparing the methylene blue solution was Human power, Human Co., Secondary distilled water purchased from Korea) was used.

Acetaldehyde ( Acetaldehyde ) And acetone ( Acetone )

Acetaldehyde, a major component of off-flavor components used in the GC test for identification of off-flavor components, was purchased from Kanto, Japan, and the purity was 85%. Acetone for acetaldehyde dilution to prepare a standard calibration curve was purchased from Duksan Co., Ltd. and the purity was 99.5%.

Example  One

Photocatalyst  Coating composition

Figure 2 is a schematic diagram showing the manufacturing process of the photocatalyst coating composition.

Referring to FIG. 2, solid 10% nano colloidal TiO ₂ was diluted with ethyl alcohol and diluted to 3% (v / v) and 5% (v / v), and the binder PU and PVB were diluted with ethyl alcohol. It was. Each of the diluted nano colloidal TiO ₂ and the binder were mixed by 100 mL, and dispersed by stirring at 7000 rpm for 1 hour using a particle disperser (EUROSTAR power control-visc, Ika-werke, Germany).

Table 1 shows an example of the photocatalyst coating composition according to the concentration (vol%) prepared by the above method.

TiO ₂ concentration (% by volume) Binder type Binder Concentration (% Volume) Example 1- (1) 3 PU 3 Example 1- (2) 3 PU 5 Example 1- (3) 3 PVB 3 Example 1- (4) 3 PVB 5 Example 1- (5) 5 PU 3 Example 1- (6) 5 PU 5 Example 1- (7) 5 PVB 3 Example 1- (8) 5 PVB 5

Example  2

Nano TiO ₂  Coating film manufacturers

Each concentration of photocatalyst coating composition (Examples 1- (1) to 1- (8)) prepared in Example 1 was coated on an OPP film 250 × 300 mm. The coating method is to fix a film specimen cut in advance in an automatic coating machine (Comate TM 3000, kipae, Co., Hawsung, Korea), and then apply 3mL of the prepared coating solution to the film with a dropper to have a cell size of 22.9㎛. The coater was coated at a speed of 100 mm / s using a coater (kipae, Co., Hawsung, Korea). The prepared coating film was dried again at room temperature for 3 days after drying for 2 hours in a drying oven (Hanback Co., Ansan, Korea) at 50 ℃.

Table 2 shows an example of the nano-TiO ₂ coating film prepared by the above method.

TiO ₂ concentration (% by volume) Binder type Binder Concentration (% Volume) Example 2- (1) 3 PU 3 Example 2- (2) 3 PU 5 Example 2- (3) 3 PVB 3 Example 2- (4) 3 PVB 5 Example 2- (5) 5 PU 3 Example 2- (6) 5 PU 5 Example 2- (7) 5 PVB 3 Example 2- (8) 5 PVB 5

Comparative Example 1

OPP film not coated with nano TiO ₂ was set as Comparative Example 1.

Comparative example  2- (1)

Coating only 3% PU binder to the OPP film was made as Comparative Example 2- (1).

Comparative Example 2- (2)

A coating of only 5% PU binder on the OPP film was made as Comparative Example 2- (1).

Comparative example  3- (1)

Coating only 3% PVB binder to the OPP film was made as Comparative Example 3- (1).

Comparative example  3- (2)

Coating only 5% PVB binder to the OPP film was made as Comparative Example 3- (2).

Test Example  One

Nano TiO ₂  Mechanical Characterization of Coating Films

In order to understand the mechanical properties of the nano-TiO ₂ coating film, the tensile strength, elongation rate and thermal adhesive strength of the film were measured. Tensile strength and elongation test was measured by cutting the specimen according to KS A 1055 using UTM (Daekyeung Co., DTU-900MH, Korea). Specimens for the test were each of Examples 2- (1) to 2- (8), Comparative Examples 2- (1) to 2- (2) and Comparative Examples 3- (1) to 3- (2). After taking three samples from the Examples and Comparative Examples, the mark was drawn at a position of 20 mm from the center of the test piece to both sides, and the test piece was fitted to the crimp of the tester. The thickness of the specimen was then measured and the maximum cutting load of the specimen was measured. Tensile velocity was 15 ± 0.5 mm / min, the tensile strength was calculated and the elongation was calculated by measuring the gage distance.

Thermal adhesive strength of the nano TiO ₂ coating of Examples 2- (1) to 2- (8), Comparative Examples 2- (1) to 2- (2) and Comparative Examples 3- (1) to 3- (2) Cut the film into 50 × 150mm and fold it in half so that the coating surface comes to the inner surface. Using a semi-automatic adhesive machine (KumKang Co., G1 300 5/2, Seoul Korea), the sealing time is 5 seconds and the cooling time. Each specimen was prepared with a cooling time of 4 seconds. In the measuring method, after fixing both surfaces of the bonded film to the clump, respectively, the maximum peeling load was measured (tension rate: 15 ± 0.5 mm / min).

3 shows the results of measuring tensile strengths of Comparative Examples 2- (1), 2- (2), Examples 2- (1), 2- (2), 2- (5), and 2- (6). It is shown.

4 shows the results of measuring tensile strengths of Comparative Examples 3- (1), 3- (2), Examples 2- (3), 2- (4), 2- (7) and 2- (8). It is shown.

3 and 4, it can be seen that the tensile strength of Example 2 is higher than that of Comparative Examples 2 to 3. Since the surface of the film is covered with TiO ₂ , which is a highly rigid inorganic material, it is considered that the maximum load when the film is broken is higher than that of the comparative example.

5 shows the results of measuring elongation rates of Comparative Examples 2- (1), 2- (2), Examples 2- (1), 2- (2), 2- (5) and 2- (6). will be.

6 shows the results of measuring the growth rates of Comparative Examples 3- (1), 3- (2), Examples 2- (3), 2- (4), 2- (7) and 2- (8). It is shown.

5 and 6, the elongation rate is inferior in flexibility and fluidity due to the inherent properties of the inorganic material, it can be seen that the comparative examples 2 to 3 more than the example 2 as opposed to the maximum load.

7 is a result of measuring the thermal adhesive strength of Comparative Examples 2- (1), 2- (2), Examples 2- (1), 2- (2), 2- (5) and 2- (6) It is shown.

8 is a result of measuring the thermal adhesive strength of Comparative Examples 3- (1), 3- (2), Examples 2- (3), 2- (4), 2- (7) and 2- (8) It is shown.

7 and 8, it can be seen that the thermal adhesive strength of Example 2 is much reduced compared to Comparative Examples 2 to 3.

From these results, it is considered that the adhesion strength is somewhat lowered because of the heat resistance against the existing adhesion temperature due to the improvement of the hardness of the film itself through the coating and the high heat resistance of the TiO ₂ itself. In addition, the film coated with the PU binder is less thermal adhesive strength than the film using the PVB binder,

In conclusion, the nano-TiO ₂ coating film of Example 2 can be seen that the maximum load, the elongation rate and the thermal adhesive strength is lower than the comparative examples 2 to 3 in terms of mechanical properties.

Test Example  2

Nano TiO ₂  Surface Analysis of Coating Films

Surface analysis of the nano TiO ₂ coating film was performed to determine the dispersion state of the nano TiO ₂ and the binder prepared by concentration on the coating film surface. Each sample was taken and subjected to pretreatment and measured using FESEM (S-4300, Hitachi, Co., Japen).

9 (a) to 9 (d) show FESEM photographs of Examples 2- (1) to 2- (4).

10 (a) to 10 (d) show FESEM photographs of Examples 2- (5) to 2- (6).

9A to 10D, the surface analysis of the nano-TiO ₂ coating film may reveal the occurrence of aggregation phenomenon on the surface of the film due to the difference in concentration between TiO ₂ and each binder PU and PVB. The reason for the aggregation phenomenon is that since TiO ₂ particles themselves are nano-size, specific surface area is increased and the attraction force is turned on, so that aggregation phenomenon occurs. In addition, the differences between a, b, c, and d in FIGS. 9a to 9d and 10a to 10d show that the difference in surface analysis results not only in TiO ₂ and concentration but also in the type of binder.

TiO ₂ In 3%, it was confirmed in FIG. 9a to 9d that PU had more uniform surface dispersion than PVB, and TiO ₂ In 5%, as the concentration of PVB increases, PVB covers TiO ₂ surface, and thus dispersion is not performed well in FIGS. 10 (a) to 10 (d).

As a result, when TiO ₂ is coated on the film, it can be seen that the PU binder is superior in terms of coating than the PVB binder.

Test Example  3

Nano TiO ₂  UV light of coating film Breaking force

UV / vis (Spectrophotometer Optizen 2120 UV & Optizen III, Seoul, Korea) was measured to measure the UV blocking ability of the nano TiO ₂ coating film. In Examples 2- (1) to 2- (8) and Comparative Examples 1 to 3, samples (10 × 50 mm) were taken and UV blocking power was measured at 200 to 700 nm, which is a range from ultraviolet to visible light. The step was measured at 10 nm.

11 shows the UV blocking effect of Comparative Examples 1 to 3.

Referring to FIG. 11, it can be seen that in addition to the difference in TiO ₂ concentration, the binder itself affects the UV blocking ability.

12 shows the UV blocking effect of Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4).

Figure 13 shows the UV blocking effect of Comparative Example 1, Examples 2- (5), 2- (6), 2- (7) and 2- (8).

12 and 13, the UV blocking ability of the nano TiO ₂ coating film showed a large difference depending on the TiO ₂ concentration, for example, it was confirmed that the UV blocking ability is excellent at 5% TiO ₂ than 3% TiO ₂ .

Furthermore, it can be seen that the UV blocking ability of the film coated with the photocatalytic coating composition to which the PVB binder is added is better than the film coated with the photocatalyst coating composition to which the PU binder is added.

From the results of this test example, it can be seen that the packaging materials of foods that are greatly affected by UV exposure show a large difference in UV blocking ability depending on the presence or absence of nano TiO ₂ coating, nano TiO ₂ concentration, and the type of binder.

Test Example  4

Bean sprouts Cotyledon  Color change measurement

The bean sprout cotyledon color change was measured three times at 6 hours intervals, after storing a total of 216 samples and storing them for 48 hours at room temperature. Thereafter, UV-lamp (Sankyo Denki Co. Japan) was examined in a box manufactured directly.

14 is a schematic diagram of the color change measurement test of the bean sprouts cotyledon.

Referring to FIG. 14, one 40 W fluorescent lamp emitting light having a dominant wavelength band of 365 nm was used as a UV-lamp, and light was irradiated from the upper part of the specimen about 20 cm away from the specimen. The internal temperature in the box was kept constant at about 25 ° C., and L, a and b values were measured using a color difference meter (CR-10, KONICA MINOLTA, Japan).

Sprouts cotyledon is a process in which the color of cotyledon is gradually changed from yellow to green. When measuring the bean sprouts cotyledon with the color difference meter, each L, a, b value comes out, L value represents the brightness of color, a value represents the color range from red to green, b value Represents the color gamut from Yellow to Blue.

Figure 15 shows the change in L value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4).

Figure 16 shows the change in L value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8).

Figure 17 shows the change in a value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4).

Figure 18 shows the change in a value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8).

Figure 19 shows the change of b value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4).

FIG. 20 shows the change of b value among the cotyledon color changes of the bean sprouts packaged with Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8).

15 to 20, the sprout value of Comparative Example 1 gradually decreased the L value after 12 hours, in the case of Example 2 it was confirmed that the color of the cotyledon part gradually changes after 24 hours. As a result, since the brightness was darkened by ultraviolet rays, the L value gradually decreased as shown in FIGS. 15 to 16, and the a value of FIGS. 17 to 18 also decreased from red to green color, indicating that the result value gradually decreased. Can be. It can be seen that the value of b of FIGS. 19 to 20 also changes from yellow color to blue color.

From the results of this test example, due to the UV-blocking effect of the nano-TiO ₂ coating film it was possible to prevent the greening phenomenon of the cotyledons of the bean sprouts, it can be seen that it is effective in maintaining the freshness of the bean sprouts.

Test Example  5

Nano TiO ₂  Of coating film Photodegradable  Measure

Photodegradability was measured using methylene blue (C ₁₆ H ₁₈ N ₃ SCl.3H ₂ O) to measure the photodegradability of the nano TiO ₂ coating film. Methylene blue used for the photolysis test was mixed with distilled water to form a liquid phase, 10 ppm was used as a quantitative measure. In order to maintain a uniform concentration of the liquid phase, the magnetic bar was stirred for 30 minutes with a stirrer (MTOPS, Co., Korea), and 20 mL of methylene blue solution was added to a Petri dish. After cutting the films prepared in Example 1, Examples 2- (1) to 2- (8) to a size of 50 × 50 mm, respectively, the specimens were prepared, and each specimen was immersed in methylene blue solution.

21 is a schematic diagram of a test method for measuring photodegradability of nano TiO ₂ coated film.

Referring to FIG. 21, the test apparatus is a device manufactured directly by the inventor for the test. In the device, a UV-lamp (Sankyo Denki Co., Japan) was irradiated and one 40W fluorescent lamp was used to irradiate light having a dominant wavelength band of 365 nm with the UV-lamp. The light was irradiated. The color change of the methylene blue solution was measured by using a color difference meter (CR-10, Konica Minolta, Japan) to measure the L value and the b value of the methylene blue solution color for 3 hours every 30 minutes.

The methylene blue is a basic dye of blue gloss having a thiazine skeleton and is tetramethylthionine chloride, and is most frequently used as a decomposing material in photodegradation experiments among TiO ₂ photocatalyst properties.

Fig. 22 shows changes in L values of methylene blue in which Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4) are immersed.

FIG. 23 shows changes in L values of methylene blue in which Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8) are immersed.

Fig. 24 shows changes in the b value of methylene blue in which Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4) are immersed.

Fig. 25 shows changes in the b value of methylene blue in which Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8) are immersed.

Referring to FIGS. 22 to 25, it can be explained that the color has changed since the nano TiO ₂ that performs the photocatalytic reaction is coated on the OPP film. When TiO ₂ receives light, OH radicals and super oxides, which are strong oxides, are generated on the surface of particles, decomposing harmful substances, and L and b values gradually increase. The amount of TiO ₂ used in the test was very small but it can be seen that MB decomposed in a short time.

Test Example  6

Nano TiO ₂  Of coating film Odor  Ingredient removal

The off-flavor component removal of the nano TiO ₂ coating film was performed by gas chromatography (Gs chromatography, GC) (Agilent Technologies, 6890, Co., USA) as a test to remove acetaldehyde, a off-flavor component generated in the bean sprouts.

26 is a schematic view showing a test method for removing off-flavor components of nano TiO ₂ coating film.

Referring to FIG. 26, the specimens prepared in Comparative Example 1 and Examples 2- (1) to 2- (8) were cut into sizes of 250 × 100 mm, respectively, to prepare specimens. The jar was put in a jar and 150g of bean sprouts were put again, and then UV-lamp was irradiated in a box manufactured directly, and the internal temperature was kept constant at 25 ° C. One 40W fluorescent lamp was used to irradiate light having a wavelength of 365 nm with a UV-lamp, and light was irradiated from the upper part of the specimen about 20 cm away from the specimen.

 The column used for GC is DB-1 (30m × 0.53mm, ID. 1.5㎛ J & W Scientific, USA), and the injector temperature is 230 ° C. Ionization Detactor, FID) was used, the temperature of the FID was 250 ℃, the initial temperature of the oven used for GC was 40 ℃, after maintaining for 5 minutes at this temperature, the temperature of the oven 10 ℃ / min It heated up to 210 degreeC by the ratio of, and maintained for 3 minutes.

Carrier gas (nitrogen) was used as the carrier gas (flow rate) was 20mL / min. The test was conducted for 8 days, and every 24 hours, 1000 μl of gas in the upper head space was collected using a gas tight syringe (Hamilon Co., Reno NV, USA). The rate of reduction of the amount of acetaldehyde, a bean sprout off-flavor component in the jar, was measured by injecting the injector portion of the.

27 is a standard calibration curve of acetaldehyde.

FIG. 27 shows a standard calibration curve with a GC instrument to measure the amount of acetaldehyde due to TiO ₂ photolysis in bean sprout packaging material.

28 shows the effect of Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4) on the concentration of acetaldehyde.

29 shows the effect of Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8) on the concentration of acetaldehyde.

Referring to FIGS. 28 and 29, the amount of acetaldehyde reduction, which is an off-flavor component generated in the bean sprouts by the nano-TiO ₂ coating film, was measured. As a result, acetaldehyde was detected from the test start date to the third day. It was confirmed that acetaldehyde occurred in each jar containing bean sprouts and Comparative Example 1 and Example 2, but the acetaldehyde concentration was significantly reduced in Example 2 compared to that of Comparative Example 1 in the amount generated. It was.

An average of 5.85 ppm of acetaldehyde was detected in bottles containing Comparative Example 1, and 5.27 ppm in bottles containing Examples 2- (1) to 2- (4), Examples 2- (5) to 2- (8) ), 5.08 ppm was detected.

In view of the above results, it can be seen that the amount of acetaldehyde generated decreases as the concentration of nano TiO ₂ increases, and as a result, it is judged that the film to which nano TiO ₂ is applied decomposes odor component effectively. Therefore, as a result of applying the TiO ₂ coating film to the bean sprouts and testing, it can be seen that the freshness of the bean sprouts can be maintained for a longer time by photodegrading acetaldehyde which is a odor component.

1 is a schematic diagram showing photoexitation inside titanium dioxide.

Figure 2 is a schematic diagram showing the manufacturing process of the photocatalyst coating composition.

3 shows the results of measuring tensile strengths of Comparative Examples 2- (1), 2- (2), Examples 2- (1), 2- (2), 2- (5), and 2- (6). It is shown.

4 shows the results of measuring tensile strengths of Comparative Examples 3- (1), 3- (2), Examples 2- (3), 2- (4), 2- (7), and 2- (8). It is shown.

5 shows the results of measuring the elongation rates of Comparative Examples 2- (1), 2- (2), Examples 2- (1), 2- (2), 2- (5) and 2- (6). will be.

6 shows the results of measuring the elongation rates of Comparative Examples 3- (1), 3- (2), Examples 2- (3), 2- (4), 2- (7) and 2- (8). will be.

7 is a result of measuring the thermal adhesive strength of Comparative Examples 2- (1), 2- (2), Examples 2- (1), 2- (2), 2- (5) and 2- (6) It is shown.

8 is a result of measuring the thermal adhesive strength of Comparative Examples 3- (1), 3- (2), Examples 2- (3), 2- (4), 2- (7) and 2- (8) It is shown.

9 (a) to 9 (d) show FESEM photographs of Examples 2- (1) to 2- (4).

10 (a) to 10 (d) show FESEM photographs of Examples 2- (5) to 2- (6).

11 shows the UV blocking effect of Comparative Examples 1 to 3.

12 shows the UV blocking effect of Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4).

Figure 13 shows the UV blocking effect of Comparative Example 1, Examples 2- (5), 2- (6), 2- (7) and 2- (8).

14 is a schematic diagram of the color change measurement test of the bean sprouts cotyledon.

Figure 15 shows the change in L value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4).

Figure 16 shows the change in L value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8).

Figure 17 shows the change in a value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4).

Figure 18 shows the change in a value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8).

Figure 19 shows the change of b value of the cotyledon color change of the bean sprouts packaged in Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4).

FIG. 20 shows the change of b value among the cotyledon color changes of the bean sprouts packaged with Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8).

21 is a schematic diagram of a test method for measuring photodegradability of nano TiO ₂ coated film.

Fig. 22 shows changes in L values of methylene blue in which Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4) are immersed.

FIG. 23 shows changes in L values of methylene blue in which Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8) are immersed.

Fig. 24 shows changes in the b value of methylene blue in which Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4) are immersed.

Fig. 25 shows changes in the b value of methylene blue in which Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8) are immersed.

26 is a schematic view showing a test method for removing off-flavor components of nano TiO ₂ coating film.

27 is a standard calibration curve of acetaldehyde.

28 shows the effect of Comparative Example 1, Example 2- (1), 2- (2), 2- (3) and 2- (4) on the concentration of acetaldehyde.

29 shows the effect of Comparative Example 1, Example 2- (5), 2- (6), 2- (7) and 2- (8) on the concentration of acetaldehyde.

Claims (13)

delete delete delete delete delete delete delete delete delete delete The photocatalyst coating composition was prepared by mixing 3-5% by volume of nano titanium dioxide having an anatase crystal structure with an average particle size of 10-30 nm and 3-5% by volume of a binder selected from polyurethane or polyvinylbutyral-cellulose. Manufacturing; And And coating the photocatalyst coating composition on one or both sides of the synthetic resin film, wherein the coating uses a bar coater. delete 12. The method of claim 11, wherein the linear velocity of the bar coater is 50 to 100 m / s.

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