KR102670930B1 - Eco-friendly ink composition and manufacturing method of packaging material using the same - Google Patents

Abstract

The manufacturing method of packaging materials using the eco-friendly ink composition according to the present invention is environmentally friendly and improves human safety by minimizing the amount of volatile organic compounds used, while drying is improved compared to conventional alcohol-based ink compositions and has excellent printing speed and working speed when printing. It works. In addition, the packaging material manufactured by the manufacturing method according to the present invention has the effect of having a high-quality printing layer with excellent color development and peel strength while minimizing the amount of volatile organic compounds used.

Description

Eco-friendly ink composition and manufacturing method of packaging material using the same {Eco-friendly ink composition and manufacturing method of packaging material using the same}

The present invention relates to an eco-friendly ink composition and a method of manufacturing packaging materials using the same. In detail, the present invention relates to an eco-friendly ink composition that can minimize the content of total volatile organic compounds (TVOC) and is safe for workers, and an eco-friendly ink composition using the same. It relates to a manufacturing method of packaging materials.

The word eco-friendly is currently becoming a trend in all industries. This is accelerating as the social responsibility of companies and investors for sustainable social development becomes more important, and it is a major trend that can no longer be ignored for the survival of companies.

Likewise, in the past, price and product quality were factors of competitiveness in the flexible packaging industry, but now, as safety and environmental issues have become more important, the flexible packaging industry is also required to actively introduce eco-friendly elements. Generally, packaging used for food, etc. uses flexible packaging technology, and a printing layer exists on the surface of the packaging material to create an attractive appearance to effectively express the image of the product and company. This printing layer is formed by printing an ink composition on a base film using a roll-to-roll gravure printing process. Gravure printing is a highly productive printing method that utilizes the quick-drying properties of solvents. It is a printing method that has about 30% of the domestic printing ink market, and the ink composition used here basically includes pigments, binder resins, and solvents.

Conventional ink compositions used in these gravure printing processes cause environmental pollution as VOC-regulated substances are used, and because more than 50% of volatile organic compounds are used as solvents in composition, they have a harmful effect on the human body and make the working environment poor. , there are problems such as causing environmental pollution. Specifically, until now, the solvent used was VOC-regulated substances such as toluene, methyl ethyl ketone (MEK), ethyl acetate (EA), and isopropyl alcohol (IPA). Harmful volatile organic compounds (VOC) were mainly used. However, these types of solvents are hazardous substances subject to industrial safety and health standards, and ink compositions containing them have a high content of total volatile organic compounds (TVOC), which not only causes environmental pollution but is also harmful to the human body. As a result, there is a problem in that the working environment becomes poor during the printing process. In particular, as safety and environmental issues have become more important recently, eco-friendly factors to minimize the use of volatile organic compounds are essential.

However, if the volatile organic compound is not used or the amount used is reduced, the volatility, which is a characteristic of the volatile organic compound, decreases, which reduces the drying efficiency and printing speed of the ink composition, and also reduces the color development power. Therefore, not only can high-quality printed matter not be manufactured, but there is a disadvantage in that the cost of the hot air process required for drying and drying equipment for this increases.

To solve this problem, Korean Patent Publication No. 10-2465827 discloses ‘a method of manufacturing packaging materials using ethanol-based ink and packaging materials manufactured therefrom.’ However, the ink composition of the above patent still has poor drying efficiency and color development, so the overall printing speed has to be adjusted slowly, and problems arise such as deterioration in process efficiency and printing quality.

In addition, packaging materials are items that come into frequent contact with the human body, especially with hands, so not only do bacteria and viruses survive on the surface and cause infection in the human body, but they also easily attract foreign substances, which reduces antibacterial and contamination resistance and makes them particularly vulnerable to ultraviolet rays. there is. In addition, to improve the durability and weather resistance of the printing layer printed on the packaging material, the packaging material is manufactured by laminating one more layer of transparent polymer film on the printing layer as the outermost layer. However, if this external film is damaged, the initial quality of the printing layer cannot be expected, and even if it is not damaged, it is vulnerable to color fading due to ultraviolet rays, and weather resistance is significantly reduced.

Accordingly, research is needed on an eco-friendly ink composition that reduces the amount of volatile organic compounds used, improves human safety, has excellent drying and color development, and has excellent durability and weather resistance compared to conventional ink compositions, as well as a method of manufacturing packaging materials using the same.

Korean Patent Publication No. 10-2465827 (2022.11.07)

The purpose of the present invention is to provide a method of manufacturing packaging materials using an eco-friendly ink composition that minimizes the amount of volatile organic compounds used, is environmentally friendly, improves human safety, improves drying properties compared to conventional alcohol-based ink compositions, and has printing and working speeds. .

Another object of the present invention relates to a method of manufacturing packaging materials using an eco-friendly ink composition that can form a high-quality printing layer with excellent color development and peel strength while minimizing the amount of volatile organic compounds used.

Another object of the present invention relates to a method of manufacturing packaging materials using an eco-friendly ink composition suitable for food packaging materials by preventing the problem of solvent remaining in the printing layer after printing and drying.

Another object of the present invention relates to a method of manufacturing a packaging material using an eco-friendly ink composition that has excellent durability and weather resistance, and has excellent antibacterial and ultraviolet ray blocking properties.

The method of manufacturing a packaging material using an eco-friendly ink composition according to the present invention includes a printing step of printing an eco-friendly ink composition on a first base layer using a roll-to-roll gravure printing process and drying it to form a print layer, and forming a print layer on the print layer. It includes an adhesion step of applying and drying an adhesive to form an adhesive layer, and a lamination step of laminating a second base layer on the adhesive layer and heat-compressing the first base layer and the second base layer.

In one example of the present invention, the eco-friendly ink composition may include a pigment, a binder resin, and a solvent, and the solvent may include an alcohol-based solvent and methyl acetate.

In an example of the present invention, in the solvent, the weight ratio of the alcohol-based solvent and the methyl acetate may be 100:25 to 150.

In one example of the present invention, the alcohol-based solvent may include ethanol.

In one example of the present invention, the adhesive may include an adhesive solution and a diluting solvent.

In one example of the present invention, the adhesive may include 100 to 1,000 parts by weight of the diluting solvent based on 100 parts by weight of the adhesive stock solution.

In one example of the present invention, the adhesive may be a polyurethane-based adhesive or a polyimine-based adhesive.

In one example of the present invention, the diluting solvent may include ethanol and methyl acetate.

In an example of the present invention, in the diluting solvent, the weight ratio of the ethanol and the methyl acetate may be 100:3 to 30.

In one example of the present invention, the eco-friendly ink composition may include 5 to 30% by weight of the pigment, 10 to 40% by weight of the binder resin, and 30 to 70% by weight of the solvent.

In one example of the present invention, the binder resin may include polyurethane resin.

In one example of the present invention, the polyurethane resin may be an alcohol-soluble polyurethane resin.

In one example of the present invention, the binder resin may further include polyvinyl butyral resin.

In an example of the present invention, in the binder resin, the weight ratio of the polyurethane resin and the polyvinyl butyral resin may be 100:25 to 500.

In one example of the present invention, the eco-friendly ink composition may further include copper particles surface-treated with polylysine.

In one example of the present invention, the copper particles surface-treated with polylysine include a) a mixing step of mixing the copper particles and polylysine in an aqueous medium, and b) the polylysine being adsorbed on the surface of the copper particle. It can be prepared including a drying step of evaporating the aqueous medium.

In an example of the present invention, in step a), the mixing weight ratio of the copper particles and the polylysine may be 100:0.01 to 10.

In one example of the present invention, step b) may include obtaining the copper particles from the aqueous medium and then drying them at a high temperature of 70 to 150°C.

In one example of the present invention, the polylysine may include any one or two or more selected from poly-L-lysine, poly-D-lysine, ε-poly-L-lysine, and ε-poly-D-lysine. You can.

In one example of the present invention, the eco-friendly ink composition may include 0.1 to 3% by weight of copper particles surface-treated with polylysine.

In one example of the present invention, the average particle diameter of the copper particles surface-treated with polylysine may be 10 to 200 nm.

In one example of the present invention, the copper particles surface-treated with polylysine may include first copper particles having a first average particle diameter and second copper particles having a second average particle diameter, and the first average particle diameter is may be 5 to 40 nm, and the second average particle diameter may be 50 to 150 nm.

In an example of the present invention, the weight ratio of the first copper particles and the second copper particles may be 1:0.5 to 2.

The method of manufacturing a packaging material according to an example of the present invention may further include a coating step of forming a protective layer by applying a coating composition on the printing layer between the printing step and the adhesion step.

In one example of the present invention, the coating composition may include copper nitrate, a UV-blocking organic compound, a polyurethane resin, and an alcohol-based solvent.

In an example of the present invention, in the coating step, the application may be performed by spraying the coating composition onto the printing layer.

In one example of the present invention, the UV-blocking organic compound may include one or two or more selected from avobenzone, oxybenzone, octyl methoxycinnamate, etc.

In one example of the present invention, the alcohol-based solvent is one or two selected from ethanol, propanol, butanol, pentanol, hexanol, 2-methoxyethanol, 2-butoxyethanol, propylene glycol, diethylene glycol, etc. It may include more.

In one example of the present invention, the coating composition contains 0.01 to 3% by weight of the copper nitrate, 0.5 to 5% by weight of the UV-blocking organic compound, 1 to 15% by weight of the polyurethane resin, and 80 to 95% by weight of the alcohol-based solvent. may include.

In one example of the present invention, the average thickness of the protective layer may be 10 to 100 ㎛.

In one example of the present invention, the pigment is an inorganic pigment containing one or two or more selected from oxides, hydroxides, sulfides, ferrocyanides, chromates, silicates, sulfates, carbonates, phosphates, carbon compounds, etc.; Organic pigments containing one or two or more selected from azo-based pigments, phthalocyanine-based pigments, nitroso-based pigments, alizarin-based pigments, aniline-based pigments, and condensed polycyclic pigments; It may include one or more selected from among.

In one example of the present invention, the pigment may have an average particle diameter of 1 to 10 ㎛.

In one example of the present invention, drying in the printing step may be performed at 50 to 80° C. for 0.5 to 10 minutes.

In one example of the present invention, the drying of the adhesion step may be performed at 10 to 40° C. for 0.5 to 10 hours.

A packaging material using the eco-friendly ink composition according to the present invention includes a first base layer; a printed layer formed by printing on the first base layer; An adhesive layer laminated on the printing layer; and a second base layer laminated on the adhesive layer.

The manufacturing method of the packaging material according to the present invention minimizes the amount of volatile organic compounds used by using an eco-friendly ink composition, which is environmentally friendly and improves human safety, while providing excellent drying properties and excellent printing and working speeds compared to conventional alcohol-based ink compositions. There is.

In addition, the method for manufacturing packaging materials according to the present invention is effective in preventing the problem of solvent remaining in the printing layer after printing and drying, making it suitable for use as food packaging materials.

In addition, packaging materials using the eco-friendly ink composition according to the present invention have the effect of having a high-quality printing layer with excellent color development and peel strength while minimizing the amount of volatile organic compounds used during printing.

In addition, the packaging material using the eco-friendly ink composition according to the present invention has excellent durability and weather resistance, and has excellent antibacterial and ultraviolet ray blocking properties.

Hereinafter, a method for manufacturing packaging materials using the eco-friendly ink composition according to the present invention will be described in detail.

Unless there is another definition in the technical and scientific terms used in this specification, they have meanings commonly understood by those skilled in the art to which this invention pertains, and the gist of the present invention is not unnecessarily explained in the following description. Descriptions of known functions and configurations that may be unclear are omitted.

In some cases in this specification, in order to avoid ambiguity of the concept of the present invention, well-known structures and devices may be omitted or may be shown in block diagram form focusing on the core functions of each structure and device.

'Include' mentioned in this specification is an open description that has the same meaning as expressions such as 'comprises', 'contains', 'has', 'characterized by', etc., and includes elements that are not additionally listed, Does not exclude materials or processes.

The singular form of the terms used in this specification may be interpreted to also include the plural form unless otherwise specified.

Numerical ranges used herein include lower and upper limits and all values within that range, increments logically derived from the shape and width of the range being defined, all doubly defined values, and upper and lower limits of numerical ranges defined in different forms. Includes all possible combinations of Additionally, unless specifically defined in the specification of the present invention, values outside the numerical range that may occur due to experimental error or rounding of values are also included in the defined numerical range.

The unit of ‘%’ used without special mention in this specification means ‘% by weight’ unless otherwise defined.

Generally, ink compositions are largely composed of pigments, binder resins, and solvents. Conventional eco-friendly ink compositions have the advantage of improved safety to the human body and eco-friendliness by using alcohol-based solvents instead of solvents of volatile organic compounds, but have the advantage of being drying. Because of this, printing speed and work speed were not good. In addition, the binder resin in the ink composition has poor miscibility with the alcohol-based solvent and has poor solubility and dispersibility, so it cannot maintain strong adhesive strength when printing on film. The pigment in the composition also has poor miscibility with the solvent, resulting in poor color development. There was a limitation that the printing quality was significantly deteriorated.

Accordingly, the eco-friendly packaging material manufactured by the method according to the present invention contains the ingredients described below in the alcohol-based eco-friendly ink composition to be printed, so that the volatile organic organic substances subject to regulation notified in Ministry of Environment Notice No. 2015-181 (2015.9.11.) Since it does not contain compounds, it is highly safe to the human body and is environmentally friendly, and has the effect of forming a printing layer with higher drying properties compared to conventional alcohol-based ink compositions. In particular, even though an alcohol-based solvent is used, the miscibility of the binder resin with the solvent is excellent, and even though an ink composition with excellent drying properties is used, it has the effect of having high adhesive strength and high color development power. Therefore, during the printing process, a printing layer that is more environmentally friendly and has higher printing quality than the conventional case can be formed on the packaging material. In addition, the eco-friendly packaging material manufactured by the method according to the present invention has excellent durability and weather resistance, antibacterial properties, and UV blocking properties, so that fading of the printed layer can be minimized, and even if the film is damaged, it has an excellent effect on inactivating bacteria and viruses. there is.

The method of manufacturing a packaging material using an eco-friendly ink composition according to the present invention includes a printing step of printing an eco-friendly ink composition on a first base layer using a roll-to-roll gravure printing process and drying it to form a print layer, and forming a print layer on the print layer. It includes an adhesion step of applying and drying an adhesive to form an adhesive layer, and a lamination step of laminating a second base layer on the adhesive layer and heat-compressing the first base layer and the second base layer. Therefore, the packaging material according to the present invention includes: a first base layer; a printing layer formed by printing the eco-friendly ink composition on the first base layer; An adhesive layer laminated on the printing layer; and a second base layer laminated on the adhesive layer.

The printing step is a step of printing an eco-friendly ink composition on a base layer and then drying it to form a print layer. In the printing step, the eco-friendly ink composition according to the present invention can be applied to various printing processes and printed, but is applied to the gravure printing process, specifically the roll-to-roll gravure printing process. It is desirable. The packaging material according to the present invention uses the eco-friendly ink composition described later in the roll-to-roll gravure printing process, enabling large-scale printing processes and minimizing changes in ink concentration due to evaporation from the ink receiving equipment even during the continuous printing process. , it is possible to form a printing layer of excellent and consistent quality.

In the gravure printing process, an eco-friendly ink composition is applied to the surface of a cylindrical copper plate, and then the copper plate is rotated while the surface of the copper plate is in contact with a substrate to load the ink composition onto the substrate. The surface of the copper plate is engraved into the desired shape to form halftone dots so that a desired printed matter can be output, and an ink composition is accommodated inside the halftone dots. Then, the ink composition is removed using a doctor blade so that the ink composition does not exist in the background area outside the halftone dots, and then the copper plate rotates and contacts the substrate to load the ink composition on the surface of the substrate and print. Preferably, the copper plate may be a low-depth laser copper plate on which halftone dots are formed by a laser.

As a preferred example, the copper plate may have a bow of 160 to 250 lines, specifically 170 to 230 lines, and a piece depth of 10 to 20 ㎛ may be used. If this is satisfied, the process cost can be lowered by reducing the amount of ink composition used, workability and productivity can be excellent, and printing quality can be improved. When a doctor blade is used so that the ink composition does not exist in the background area of the copper plate, the angle of the doctor blade with respect to the copper plate may be sufficient to allow the ink composition to be well removed, for example, 30 to 70 degrees, specifically 35 degrees. It may be from 65 degrees.

The printing step includes a composition loading step of printing the eco-friendly ink composition on the surface of the first base layer and a drying step of drying the ink composition printed and loaded on the surface of the first base layer to form a print layer. It can be included.

The composition loading step is a step of loading an ink composition on the surface of the first base layer by drying the ink composition printed and loaded on the surface of the first base layer.

The drying step is a step of forming a printed layer on the first base layer by drying the ink composition printed and loaded on the surface of the first base layer. The drying can be performed in various ways, for example It may be hot air drying. As heat energy can be continuously supplied after printing, the solvent can be easily evaporated and removed. In particular, since the ink composition contains copper particles surface-treated with polylysine, which will be described later, the solvent can be effectively evaporated, resulting in high dryness. You can expect it. The drying temperature may be, for example, 50 to 100°C, specifically 60 to 90°C. Since the drying time varies depending on environmental conditions such as humidity, temperature, and wind volume, it can be appropriately adjusted as the time for complete drying to suit each environment, for example, 3 to 24 hours, specifically, 3 to 12 hours. You can.

In the printing step, the eco-friendly ink composition includes a pigment, a binder resin, and a solvent, and the solvent includes alcohol and methyl acetate. At this time, the weight ratio of the alcohol-based solvent and the methyl acetate may be, for example, 100:25 to 150 in that the above-mentioned effects such as dispersibility, color development, and drying property can be further improved.

The alcohol-based solvent includes ethanol, and by using ethanol and methyl acetate as solvents, the content of total volatile organic compounds (TVOC) can be minimized, and in the packaging material manufacturing process, conventional It can provide a relatively safer environment for preparedness workers.

In the eco-friendly ink composition according to the present invention, the solvent includes an alcohol-based solvent and methyl acetate, so that the dispersibility, solubility, and miscibility of other components in solvents are improved compared to the case where methyl acetate is not used and only the alcohol-based solvent is used. Not only can it improve, but drying properties and coloring power can also be improved.

The composition ratio of the pigment, the binder resin, and the solvent may include, for example, 5 to 30% by weight of the pigment, 10 to 40% by weight of the binder resin, and 30 to 70% by weight of the solvent. This may be desirable in terms of maximizing the above-mentioned effects.

The pigment may be appropriately selected and used from various types of pigments known in the art to achieve the required color, for example, oxide, hydroxide, sulfide, ferrocyanide, chromate, silicate, sulfate, carbonate, phosphate. , an inorganic pigment containing any one or two or more selected from carbon compounds, etc.; and organic pigments containing one or two or more selected from azo-based pigments, phthalocyanine-based pigments, nitroso-based pigments, alizarin-based pigments, aniline-based pigments, and condensed polycyclic pigments; It may include one or more selected from among. The average particle diameter of the pigment is sufficient to be well dispersed in the ink composition and achieve the required color development, and may be, for example, 1 to 10 ㎛.

The binder resin may include at least one selected from polyurethane (PU) resin and polyvinyl butyral (PVB) resin. Specifically, it is preferable that polyurethane resin is used as the binder resin, and it is more preferable that polyurethane resin and polyvinyl butyral resin are used together. When the polyurethane resin and the polyvinyl butyral resin are used together, their weight ratio may be preferably, for example, 100:25 to 500 in order to better achieve the above-mentioned effects, such as improved adhesion.

The polyurethane resin is preferably an alcohol-soluble polyurethane resin so that it can dissolve well in alcohol-based solvents. The alcohol-soluble polyurethane resin may be a commercially available, known resin. Likewise, the polyvinyl butyral resin may be a commercially available, known resin.

The weight average molecular weight of the polyurethane resin or the polyvinyl butyral resin is sufficient to have good miscibility with the alcohol-based solvent and adequate adhesion to a substrate such as a film, for example, 3,000 to 100,000 g/mol. , specifically, 5,000 to 50,000 g/mol, more specifically 5,000 to 20,000 g/mol.

The solvent used in the eco-friendly ink composition may further include water. The ink composition according to the present invention may be an aqueous ink composition, and when water is further included as a solvent, the amount of water used is such that each component can be well dispersed, for example, water per 100 parts by weight of the alcohol-based solvent. This can be adjusted to be included in the ink composition at 50 to 300 parts by weight. Through this, the risk of fire can be reduced by increasing the flash point, and the manufacturing cost of the ink composition can be lowered.

The eco-friendly ink composition according to an example of the present invention may further include additives in terms of improving physical properties, processability, workability, and storage stability. When the ink composition further includes additives, they may be included in an amount of, for example, 0.1 to 5% by weight to implement the function of each additive. Types of the above additives include printability improvement aids, storage stability improvers, processability improvers, viscosity regulators, drying regulators, oxidizing agents, anti-foaming agents, plasticizers, light stabilizers, anti-friction agents, anti-staining agents, anti-scratch agents, dispersants, film reinforcers, and anti-blocking agents. , one or more selected from anti-static agents, adhesion reinforcing agents, heat-resisting reinforcing agents, and transferability improving agents, etc. may be used. Specific examples of printability improvement aids or storage stability improvers include rosin-modified resin, and specific examples of processability improvers include wax and the like. Commercially available products may be used. Specific examples of the wax include various synthetic waxes such as paraffin wax, montan wax, Sasol wax, polyethylene wax, polypropylene wax, Fischer-Trow wax, opium wax, and microcrystalline wax, petroleum wax, hydrocarbon wax, and Miri. It may include any one or two or more selected from fatty acids such as stick acid, palmitic acid, and stearic acid and their derivatives, mineral wax, carnauba wax, candela wax, and beeswax wax.

As the packaging material according to the present invention uses the above-mentioned eco-friendly ink composition to form a printing layer, the miscibility and drying properties of the pigment and binder resin of the ink composition are improved, and the physical properties such as color development and adhesive strength of the formed printing layer are improved. It has excellent effects. In particular, it is possible to prevent the problem of a decrease in the transfer ability of the ink to the substrate by partially drying quickly. In detail, the eco-friendly ink composition according to the present invention forms a printing layer through a roll-to-roll gravure printing process, so a copper plate is used at this time. After the ink composition is applied to the surface of the copper plate, the copper plate is rotated while the surface portion of the copper plate is in contact with the substrate to form a printing layer on the substrate. The area where the ink is applied is partially dried first on the surface of the copper plate. This may cause plate brittleness, which may result in poor printing. However, when the ink composition according to the present invention has the composition and/or composition ratio described above, high drying power is secured to the extent that the plate brittleness does not occur. There is an effect that can be done.

Typically, the gravure printing process is an environment in which heat energy required for vaporization of the solvent can be sufficiently supplied as hot air drying is performed during or after printing, but even if the environment is maintained continuously, heat energy can be quickly transferred to the ink composition. If not done, drying properties may decrease. In addition, commonly used packaging materials have poor heat resistance, so the drying temperature cannot be maintained high, resulting in slow drying speed and limitations in working speed. However, the ink composition according to the present invention can alleviate this problem by having the above-described composition and/or composition ratio, and when it further contains copper particles surface-treated with polylysine, which will be described later, the ink composition can be infiltrated through the surrounding air. Heat energy can be transferred more quickly to the solvent. Therefore, it can be expected that drying properties will be improved over conventional ink compositions using volatile organic compound-based solvents.

That is, preferably, the eco-friendly ink composition according to the present invention may further include copper particles surface-treated with polylysine. Since the copper particles have high thermal conductivity, surrounding heat (since drying facilities such as hot air drying are generally provided) can be better transmitted to the solvent of the ink composition. Furthermore, by bonding polylysine to the surface of the copper particle and treating the surface, it can have a hydrophilic surface and greatly improve dispersibility and miscibility in solvents including alcohol-based solvents and methyl acetate. The surface of copper particles is generally hydrophobic, so it has the disadvantage of not being well dispersed in alcohol-based solvents, especially when it has a nanoscale particle size. However, when the surface is treated with polylysine, it has a dispersible miscibility in the ink composition according to the present invention. It can be greatly improved. Therefore, even when particles other than pigments are used, the dispersion power of the particles in the solvent is improved, and drying properties can be significantly improved without a significant decrease in color development power.

In addition, since cationic polylysine particles are bonded to the anionic surface of the copper particles, dispersibility is improved by inter-particle repulsion in the solvent, and the viscosity of the solvent is reduced, allowing ink to be applied during the printing step through the roll-to-roll gravure printing process. This can minimize the problem of plate nicking due to the ink settling in the grooves of the copper plate drying too quickly.

In particular, since copper particles exist inside the printed layer attached to the substrate after drying, the adhesion of the copper particles to the substrate may decrease. When copper particles surface-treated with polylysine are used, polylysine, which has many NH groups, is alcohol soluble. By chemically bonding with polyurethane, it adheres more firmly and peel strength can be further improved.

When the eco-friendly ink composition includes copper particles surface-treated with polylysine, it may contain 0.1 to 3% by weight, thereby minimizing the decrease in color development and the adhesive strength of the printing layer, and significantly improving drying properties. The aforementioned effects can be better implemented.

The average particle diameter of the copper particles surface-treated with polylysine may be preferably, for example, 10 to 200 nm so that heat can be efficiently transferred to the solvent and well dispersed in the solvent. Preferably, the copper particles may include first copper particles having a first average particle diameter and second copper particles having a second average particle diameter. At this time, the first average particle diameter may be 5 to 40 nm, and the second average particle diameter may be 50 to 150 nm. In this way, when particles with an average particle diameter in a different range of 2 or more are used, the particles can exist in a denser and higher density state when forming the printing layer, thereby forming a printing layer with higher adhesive strength and lowering the color development power. It has the effect of minimizing. The weight ratio of the first thermally conductive particles and the second thermally conductive particles is sufficient to realize the above effect, and may be, for example, 1:0.5 to 2.

In a preferred example, the copper particles surface-treated with polylysine include a) a mixing step of mixing copper particles and polylysine in an aqueous medium, and b) evaporating the aqueous medium so that the polylysine is adsorbed on the surface of the copper particle. It can be manufactured including a drying step.

In step a), the mixing weight ratio of the copper particles and the polylysine is preferably such that the polylysine is well adsorbed on the entire surface of the copper particles, and may be, for example, 100:0.001 to 10.

The drying step of step b) is sufficient to ensure that the polylysine is well attached to the surface of the copper particles, and may include, for example, a process of drying the copper particles after obtaining them from the aqueous medium. At this time, drying may be performed at a high temperature of 70 to 150°C.

The polylysine may be of various isomers of polylysine, for example, any one selected from poly-L-lysine, poly-D-lysine, ε-poly-L-lysine, and ε-poly-D-lysine, etc. It may contain two or more.

In this way, by applying the above-described eco-friendly ink composition to the gravure printing method in the printing step, packaging materials on which desired letters, pictures, etc. are printed can be manufactured.

The method of manufacturing a packaging material according to a preferred example may further include a coating step of forming a protective layer by applying a coating composition on the printing layer between the printing step and the adhesion step. Here, the coating composition includes copper nitrate, a UV-blocking organic compound, a polyurethane resin, and an alcohol-based solvent. Therefore, antibacterial properties are improved and fading of the printed layer caused by ultraviolet rays can be minimized. Since packaging materials are items that frequently come into contact with the human body, especially with hands, bacteria and viruses can survive on the surface for a long time, causing infection in the human body, and can easily cause physical damage to the second base material layer. However, the packaging material according to the present invention forms a protective layer of a specific composition and/or composition ratio on the printing layer, thereby minimizing color fading due to ultraviolet rays and maintaining the initial quality of the printing layer for a long period of time even when the second base layer is damaged. There is an effect.

The copper nitrate is an ingredient that imparts antibacterial properties, and together with the copper particles surface-treated with polylysine of the printing layer, it imparts antibacterial properties. While the antibacterial performance of the copper particles in the printed layer may be reduced as the surface is treated with polylysine, copper nitrate has high solubility in alcohol-based compounds, so the coating composition is absorbed by alcohol-based solvents in the process of forming a protective layer. Dissolved copper nitrate precipitates inside the protective layer as copper nitrate particles, greatly improving the antibacterial effect. In particular, copper nitrate dissolved in an ionic state in an alcohol-based solvent precipitates by evaporation of the solvent, and as it precipitates to the upper side of the polyurethane resin, the probability of copper nitrate particles being formed on the surface of the protective layer greatly increases. In addition, copper nitrate particles have a specific gravity about 3 times smaller than copper metal particles, so they increase the probability of precipitation on the top of the polyurethane resin relative to copper metal particles. Therefore, since the copper nitrate particles have a relatively higher density at the surface than at the bottom of the protective layer of the polyurethane matrix, the antibacterial performance may be more active at the surface of the packaging material. Since bacteria and viruses are introduced from the outside of the packaging material due to damage to the second base layer, etc., if the copper nitrate particles are present at a high density on the surface of the protective layer, the antibacterial effect can be effectively implemented for a long period of time.

The UV-blocking organic compound may be a known organic compound, and may include, for example, one or two or more selected from avobenzone, oxybenzone, and octyl methoxycinnamate. You can.

The polyurethane resin is preferably an alcohol-soluble polyurethane resin so that it can dissolve well in alcohol-based solvents. The alcohol-soluble polyurethane resin may be a commercially available, known resin. Likewise, the polyvinyl butyral resin may be a commercially available, known resin.

The weight average molecular weight of the polyurethane resin is sufficient to have good miscibility with the alcohol-based solvent and adequate adhesion to a substrate such as a film, for example, 3,000 to 100,000 g/mol, specifically 5,000 to 50,000. It may be g/mol, more specifically 5,000 to 20,000 g/mol.

The alcohol-based solvent is, for example, one or two or more alcohol-based solvents selected from ethanol, propanol, butanol, pentanol, hexanol, 2-methoxyethanol, 2-butoxyethanol, propylene glycol, and diethylene glycol. It may be included, and it is preferable to use ethanol in terms of excellent mutual stability with the printing layer due to the alcohol-based solvent remaining in the printing layer below.

The coating composition includes 0.01 to 3% by weight of the copper nitrate, 0.5 to 5% by weight of the UV-blocking organic compound, 1 to 15% by weight of the polyurethane resin, and 80 to 95% by weight of the solvent to effectively achieve the above-mentioned effects. This may be desirable.

In the coating step, the application may be preferably performed by spraying the coating composition onto the printing layer. The spraying amount can be adjusted to an amount that ensures that the average thickness of the protective layer can well protect the printing layer. For example, it may be desirable to spray so that the average thickness of the protective layer is 10 to 100 ㎛. .

The adhesion step is a step of forming an adhesive layer by applying and drying an adhesive on the printed layer formed on the first base layer in the printing step, and then in the lamination step, the second base layer is attached to the first base layer and the printed layer. Ensure that it is well heat-compressed to form a sturdy laminated film.

In the adhesion step, the adhesive may include an adhesive solution and a diluting solvent. If this is satisfied, the durability of the packaging material and the peel strength of the printed layer can be improved by increasing the adhesion (curing) time of the adhesive applied on the printed layer when forming an adhesive layer and lamination.

The adhesive solution may be a solvent-free polymer composition that does not contain a solvent or contains 5% by weight or less of the total weight of the adhesive solution. The adhesive solution is used in the field of packaging materials, and any type suitable for adhesion to the base layer material may be used. For example, polyurethane-based adhesives, polyimine-based adhesives, etc. may be used. As a specific example, a solvent-free polyurethane adhesive solution may be used as the polyurethane-based adhesive. As a specific example, the polyimine-based adhesive may be an imine-based water-based anchor coating and can improve adhesion between base layers. Additionally, the adhesive solution may be a two-component type consisting of a base material and a hardener. The curing agent may be an isocyanate-based curing agent, and for example, an aliphatic isocyanate-based compound including toluene diisocyanate (TDI) may be used. When a hardener is used, it can be used in an amount of 1 to 20 parts by weight per 100 parts by weight of the main material in order to better achieve the above-mentioned effects, such as durability of the packaging material and peel strength of the printed layer.

The diluting solvent may contain components of the solvent of the above-described eco-friendly ink composition, and for example, it preferably contains ethanol and methyl acetate, which have the same composition as the solvent of the eco-friendly ink composition forming the printing layer. If this is satisfied, the interconnectivity and mutual stability with the already formed printed layer are improved, so that the peel strength can be further improved. When ethanol and methyl acetate are used as the diluting solvent, their weight ratio may be sufficient to achieve the above-described effect, and may be, for example, 100:3 to 30.

The weight ratio of the adhesive stock solution and the diluting solvent can be appropriately adjusted as long as it can achieve the above-mentioned effect. For example, the adhesive may include 100 to 1,000 parts by weight of the diluting solvent based on 100 parts by weight of the adhesive stock solution. You can.

The lamination step is a step of lamination of the first base layer and the second base layer by thermal compression. Specifically, in the lamination step, heat compression may be performed after the second base layer is laminated on the first base layer. The compression may be performed by a pressure roll, and the diameter of the pressure roll used at this time may be 200 to 240 mm, specifically 215 to 225 mm, and the contact distance between the pressure roll and the base layer may be 1450 to 1600 mm. . Through this, the pressing effect can be increased and the contact force can be improved. The pressing temperature in the lamination step may be sufficient to allow the first and second substrate layers to be sufficiently laminated to form a durable laminate, and may be, for example, 80 to 150°C.

The method of manufacturing a packaging material according to the present invention may further include a cooling step of drying the laminated packaging material after the lamination step, through which it is possible to manufacture a packaging material with excellent durability. The drying can be performed by a pressure roll, and of course, a pressure roll within the range of the diameter of the pressure roll and the contact distance between the pressure roll and the base layer can be used. The cooling temperature may be, for example, in the room temperature range, specifically 10 to 30°C. The cooling time may be sufficient as long as the base layers are sufficiently bonded to form a durable laminate, and may be appropriately adjusted depending on the cooling temperature.

The second base layer may be formed in plurality, and each of the plurality of second base layers may have different materials.

The material of the base layer may be any commonly used packaging material. For example, the base layer may be a film layer. Specifically, the first base layer and the second base layer may be a first film layer and a second base layer, respectively. There may be 2 film layers. Specific examples of the base layer include one or two or more selected from polyethylene, polypropylene, polyethylene terephthalate, polyvinylidene chloride (PVDC), and nylon. It can be included. Specific examples of polyethylene or polypropylene include oriented polypropylene, vapor-deposited non-oriented polypropylene, non-oriented polypropylene, and linear low-density polyethylene. In addition, of course, the base layer may be made of various materials, such as metal foil such as aluminum deposited on the above-described polymer base.

The packaging material according to the present invention is preferably used, for example, as a packaging material made of a polymer film, especially as a food packaging material. In particular, packaging materials manufactured with the eco-friendly ink composition according to the present invention have very low residual solvents and are more human-friendly than conventional products, so they can minimize problems that may negatively affect the human body, making them suitable for use as food packaging materials.

Hereinafter, the present invention will be described in detail through examples. However, these are intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to the following examples.

<Ink composition manufacturing process>

Pigment (Black N-220, Red 5702 or Blue 39580S or Yellow 1444, Chemtech Commerce) 15 kg, alcohol-soluble polyurethane resin (PU-3300B, iSuo Chem) 10 kg, polyvinyl butyral resin (B06HX, Kelley Associates) 15 kg and 60 kg of solvent were mixed and thoroughly mixed to prepare an ink composition. The solvent included an alcohol-based solvent including ethanol and methyl acetate, and the weight ratio of the alcohol-based solvent and the methyl acetate was 5:2.

<Packaging material manufacturing process>

The ink composition was printed on an stretched polypropylene (OPP) base layer using a roll-to-roll gravure printing process and dried with hot air at 70°C for 1 minute to form a printed layer. The copper plate used in the gravure printing process was one with 190 lines and an engraving depth of 14 ㎛. Next, an adhesive was applied on the printed layer, non-stretched polypropylene (CPP) was laminated, and then heat-compressed to prepare a packaging material with a thickness of 50 ㎛.

The adhesive used was a mixture of adhesive stock solution and diluted solvent at a weight ratio of 1:5. The adhesive stock solution consists of the main two-part polyurethane adhesive (HIPOL 880ET, HICHEM) and a curing agent (880H, HICHEM), and the curing agent was used in an amount of 10 parts by weight based on 100 parts by weight of the main agent. The diluting solvent used was a mixture of ethanol and methyl acetate in a ratio of 100:10.

A packaging material was manufactured in the same manner as in Example 1, except that an ink composition was prepared by further mixing 0.7 kg of copper particles with an average particle diameter of 30 nm in the ink composition manufacturing process of Example 1.

Packaging material in the same manner as in Example 1, except that an ink composition was prepared by further mixing 0.7 kg of copper particles surface-treated with polylysine prepared in the surface-treated copper particle manufacturing process below in the ink composition manufacturing process of Example 1. was manufactured.

<Surface treated copper particle manufacturing process>

Copper particles with an average particle diameter of 30 nm were added to an aqueous polylysine solution (poly-L-lysine, weight average molecular weight: 150,000~300,000, concentration: 0.1% by weight) (P8920, Sigma Aldrich) and incubated slowly at 25°C for 1 hour. After stirring at high speed, the mixture was sufficiently dried at 80°C to prepare copper particles surface-treated with polylysine. At this time, the weight ratio of the copper particles and the polylysine aqueous solution was set to 1:10.

Except that after forming the printing layer in the packaging material manufacturing process of Example 3, the coating composition prepared in the coating composition manufacturing process below was spray-applied onto it and dried at 25°C for 4 hours to form a protective layer with an average thickness of 30 ㎛. A packaging material was manufactured in the same manner as in Example 3 (after forming a protective layer, a packaging material was manufactured through adhesive application and heat compression in the same manner as in Example 3).

<Coating composition manufacturing process>

Mix 1% by weight of copper metal nanoparticles (average particle diameter: 70 nm), 2% by weight of oxybenzone, 8% by weight of alcohol-soluble polyurethane resin (PU-3300B, iSuo Chem), and 89% by weight of ethanol and mix thoroughly to form a coating composition. was manufactured.

A packaging material was prepared in the same manner as in Example 4, except that in the coating composition manufacturing process of Example 4, copper nitrate particles were used instead of copper metal nanoparticles to prepare a coating composition in which copper nitrate was dissolved in ethanol.

[Experimental Example 1] Total volatile organic compounds test

The total amount of volatile organic compounds generated during the process of the ink composition and coating composition prepared in Examples 1 to 5 was measured. Specifically, the ink composition was gravure printed and dried on stretched polypropylene (OPP) to form an ink layer, and then the coating composition was sprayed and dried on the ink layer to produce a specimen in which a protective layer was formed. At this time, the total amount of volatile organic compounds generated during the total production time of the specimen was measured. The volatile organic compounds are regulated compounds notified in Ministry of Environment Notice No. 2015-181 (September 11, 2015). In addition, during the gravure printing, a copper plate with 190 lines and an engraving depth of 14 ㎛ was used.

As a result, the total volatile organic compounds were measured to be less than 0.003 mg/m ² h for both the ink composition and the coating composition of Examples 1 to 5, indicating that virtually no volatile organic compounds are generated within the error range. Confirmed.

[Experimental Example 2] Color development test

Color development was measured during gravure printing using the ink compositions prepared in Examples 1 to 3. Specifically, the ink composition was gravure printed on stretched polypropylene (OPP) using a gravure printing equipment to form an ink layer, and then dried with hot air for 9 hours to produce a specimen. Then, the CIELAB color space was measured for the specimen using X-Rite's eXactTM device, and the results are shown in Table 1 below. Here, color coordinates are expressed as L*, a*, b*, where L* is the brightness, a* is the three-dimensional coordinate that represents the degree of red and green, and b* is the degree of yellow and blue. In addition, during the gravure printing, a copper plate with 190 lines and an engraving depth of 14 ㎛ was used.

[Experimental Example 3] Dry laminate strength test

The dry laminate strength was measured on specimens obtained by gravure printing the ink compositions prepared in Examples 1 to 3 on films. Specifically, the ink composition was printed on stretched polypropylene (OPP) using a gravure printing facility and dried with hot air at 60°C for 1 minute to form a printed layer. During the gravure printing, a copper plate with 190 lines and an engraving depth of 14 ㎛ was used. Then, the adhesive used in Example 1 was applied on the printed layer, non-stretched polypropylene (CPP) was laminated, and then heat treated in an oven at 60° C. for 12 hours to produce a specimen. At this time, the specimen was cut to a size of 15 mm in width, and the T-type peel strength of each cut film was measured at a speed of 300 mm/min using a universal testing machine. The results are shown in Table 1 below.

[Experimental Example 4] Drying performance test

After gravure printing the ink compositions prepared in Examples 1 to 5 on a film, the time taken for complete drying and the maximum printing speed without problems were measured. Specifically, the ink composition was printed on stretched polypropylene (OPP) using gravure printing equipment and dried with hot air at 60°C to form a printed layer. And the time it took for it to dry completely was measured. At this time, the standard for complete drying was to ensure that the print layer did not smear when wiped with another film. Divide the print layer into several zones to form multiple print layers, and repeat the amount of smudge by wiping the print layer in each zone with the film at 5-second intervals. Measured.

[Experimental Example 4] Antibacterial test

An antibacterial test was performed according to the test standards of KS K 0693 using the packaging materials prepared in Examples 1 to 5 as specimens. At this time, the specimen was used by damaging the CPP film of the outermost base layer with a knife to expose the printing layer or protective layer, and then leaving it in an environment of 30°C and 80% relative humidity for 2 weeks. For these specimens, the antibacterial properties were tested using Staphylococcus aureus ATCC 6538 and Klebisiella pneumoniae ATCC 4352 as test bacteria. As a control, a packaging material was manufactured in the same manner as in Example 1, except for the printing process using the ink composition, and a packaging material without a printing layer and a protective layer was used. And the results are shown in Table 1 below.

[Experimental Example 5] Discoloration resistance test by ultraviolet rays

The UV blocking performance of the packaging materials prepared in Examples 1 to 5 was evaluated. Specifically, the printing layer and the protective layer of the packaging material were irradiated with ultraviolet rays using an ultraviolet irradiation device for 20 days, and then the color development power before and after ultraviolet irradiation was measured and compared in the same manner as in Experimental Example 2, and the results are shown in Table 1 below. . At this time, the result was expressed as ‘no change’ if the discoloration was less than 1%, and as ‘discoloration’ if the discoloration exceeded 1%.

composition Example One 2 3 4 5 Copper particles in ink composition Surface treatment X O O O untreated O coating composition copper metal nanoparticles X X X O copper nitrate particles O Color development black L* 6.60 5.96 6.48 - - a* 1.86 1.82 1.78 - - b* 2.23 2.03 2.18 - - off-white L* 89.63 82.45 85.15 - - a* 3.12 3.09 3.10 - - b* 21.92 18.16 20.99 - - Dry laminate strength (g/mm) 180 172 193 - - Drying time (seconds) 45 35 35 - - Antibacterial properties (bacteria reduction rate compared to control group) below 10 55% 73% 81% More than 99% Resistance to discoloration by UV rays discoloration discoloration discoloration no change no change

Claims (6)

A printing step of printing an eco-friendly ink composition on the first base layer using a roll-to-roll gravure printing process and drying it to form a print layer.
An adhesion step of applying adhesive on the printing layer and drying to form an adhesive layer, and
A laminating step of laminating a second base layer on the adhesive layer and heat-compressing the first base layer and the second base layer,
The eco-friendly ink composition includes pigment, binder resin, copper particles surface-treated with polylysine, and a solvent,
The binder resin includes polyurethane resin,
A method of manufacturing a packaging material using an eco-friendly ink composition, wherein the solvent includes an alcohol-based solvent and methyl acetate. delete According to paragraph 1,
The adhesive includes an adhesive stock solution and a diluting solvent, and includes 100 to 1,000 parts by weight of the diluting solvent based on 100 parts by weight of the adhesive stock solution,
The adhesive is a polyurethane-based adhesive or a polyimine-based adhesive,
The diluting solvent includes ethanol and methyl acetate, and the weight ratio of the ethanol and the methyl acetate is 100:3 to 30. delete According to paragraph 1,
The copper particles surface-treated with polylysine,
a) a mixing step of mixing copper particles and polylysine in an aqueous medium, and
b) a drying step of evaporating the aqueous medium so that the polylysine is adsorbed on the surface of the copper particles. delete