KR20240138399A - Water-soluble primer composition, and interior film comprising primer-layer formed therefrom - Google Patents

Abstract

The present invention relates to an aqueous primer composition comprising a polyurethane aqueous dispersion, a polyolefin imine aqueous solution, and water, wherein the polyurethane aqueous dispersion has a glass transition temperature of -25 to 30°C, and the polyolefin imine aqueous solution has a weight average molecular weight of 1,000 to 90,000 g/mol based on solid content, and an interior film comprising the same.

Description

WATER-SOLUBLE PRIMER COMPOSITION, AND INTERIOR FILM COMPRISING PRIMER-LAYER FORMED THEREFROM

The present invention relates to a water-based primer composition having excellent storage stability, transfer rate to a substrate layer, and printability, and an interior film comprising a primer layer formed therefrom.

Various printing methods, such as flexo printing, gravure printing, inkjet printing, and screen printing, are utilized as a method of applying a specific color or forming a pattern on various types of substrates. In particular, gravure printing and flexo printing are widely used because they can be mass-produced at high speeds. However, gravure printing and flexo printing have limitations in that they require additional costs and time, such as producing a copper plate, for design changes, and the resolution of the image after printing is insufficient. In addition, solvent-based inks containing organic solvents are typically used in conventional printing methods, but such solvent-based inks cause environmental problems by emitting a large amount of volatile organic compounds (VOCs) due to the organic solvents contained in the ink.

As an alternative to this, digital printer printing and the use of water-based ink have been proposed. When using a digital printer printing method, for example, a primer layer is formed on a release film including a release layer, a printed layer is formed on the primer layer by a digital printer, the primer layer and the printed layer are transferred onto a substrate film, and then the release film is peeled off to manufacture a laminate in which the substrate film, the printed layer, and the primer layer are laminated in that order, and then a surface protection layer can be formed on the laminate. For example, Korean Patent No. 1798683 (Patent Document 1) discloses a method for manufacturing a decorative sheet, which includes the steps of: forming a primer layer on a release film having a smooth surface; forming a design layer on the primer layer; transferring the primer layer and the design layer onto a substrate; peeling the release film on the substrate; laminating an ionizing radiation curable resin composition on the primer layer formed on the substrate; and crosslinking and curing the ionizing radiation curable resin composition to form a surface protection layer. However, as described above, when using a conventional digital printer printing method, there was a problem of poor printability due to the difference in surface tension between the ink and the printing layer.

Therefore, there is a need for research and development on a water-based primer composition that has excellent storage stability, transfer rate to a substrate layer, and printability, and is applicable to digital printing.

Korean Patent No. 1798683 (Published on October 21, 2013)

The present invention seeks to provide an interior film including an aqueous primer composition having excellent storage stability, transfer rate to a substrate layer, and printability and applicable to a digital printing method, and an ink layer formed therefrom.

The present invention comprises a polyurethane aqueous dispersion, a polyolefin imine aqueous solution and water,

The above polyurethane aqueous dispersion has a glass transition temperature of -25 to 30°C.

The above polyolefin imine aqueous solution provides an aqueous primer composition having a weight average molecular weight of 1,000 to 90,000 g/mol based on solid content.

In addition, the present invention comprises a substrate layer;

An ink layer formed on the above substrate layer;

A primer layer formed on the ink layer and formed from the aqueous primer composition; and

An interior film is provided, comprising a transparent protective layer formed on the primer layer.

The water-based primer composition according to the present invention has excellent storage stability, transfer rate to a substrate layer, and printability, is suitable for digital printing, and is environmentally friendly because it is water-based and has a low VOC content.

In addition, the interior film according to the present invention including a primer layer formed from the above-described water-based primer composition has excellent image resolution of the ink layer and excellent adhesion between each layer, thereby achieving excellent productivity.

The present invention is described in detail below.

In this specification, when a part is said to "include" a certain component, this does not mean that other components are excluded, but rather that other components may be included, unless otherwise specifically stated.

Additionally, in this specification, when it is said that a layer is located "on" another layer, this includes not only cases where the layer is in contact with the other layer, but also cases where another layer exists between the two layers.

Furthermore, in the present specification, the “glass transition temperature” of the resin is measured by a conventional method known in the art, and can be measured by, for example, differential scanning calorimetry (DSC).

Additionally, the “weight average molecular weight” can be measured by a method well known in the art, and can represent a value measured by, for example, a GPC (gel permeation chromatograph) method.

The equivalent or functional group content, such as "amine value", can be measured by methods well known in the art, and can represent a value measured by, for example, a titration method.

The "average particle size" is measured by a conventional method known in the art, and can be measured by, for example, laser light scattering (LLS), and the "average particle size" can be an average value of particle diameters of 10% (D ₁₀ ) to 90% (D ₉₀ ) of the cumulative distribution in the particle size distribution measured as described above.

Additionally, “viscosity” is measured by a conventional method known in the art, and can be measured, for example, using a Brookfield viscometer (rotating spindle viscometer) at room temperature (25°C).

Mercury primer composition

The water-based primer composition according to the present invention comprises a polyurethane aqueous dispersion, a polyolefin imine aqueous solution, and water.

Polyurethane aqueous dispersion

Polyurethane aqueous dispersion plays a role in providing adhesion to the primer layer during the manufacture of interior films.

The above polyurethane aqueous dispersion has a glass transition temperature (Tg) of -25 to 30°C. Specifically, the polyurethane aqueous dispersion may have a glass transition temperature (Tg) of -20 to 25°C. At this time, when the glass transition temperature of the polyurethane aqueous dispersion is within the above range, the adhesion to the PVC material is good, so that the interlayer adhesion after heat lamination is excellent. On the other hand, when the glass transition temperature of the polyurethane aqueous dispersion is below the above range, the surface of the manufactured primer layer may be tacky, which may cause blocking when the film is dried, and when it exceeds the above range, the brittle nature of polyurethane may cause a problem of non-adhesion with the transparent protective layer during heat lamination.

In addition, the polyurethane aqueous dispersion may be a polyurethane aqueous dispersion in which, for example, a polycarbonate-based polyurethane manufactured by reacting a polycarbonate with an isocyanate, or a polyether-based polyurethane manufactured by reacting a polyether polyol with an isocyanate, is dispersed in water. Since polycarbonate-based polyurethanes and polyether-based polyurethanes do not undergo hydrolysis, they can exhibit the adhesive properties inherent to the polyurethane structure even after heat lamination. Specifically, the polyurethane aqueous dispersion may be a polycarbonate-based polyurethane dispersed in water.

The above polyurethane aqueous dispersion may have a viscosity of 10 to 3,000 cps or 30 to 2,500 cps at 25°C. If the viscosity of the polyurethane aqueous dispersion at 25°C is less than the above range, the viscosity of the primer composition is too low, causing problems such as bleeding during coating. If it exceeds the above range, the viscosity of the primer composition is high, causing surface unevenness in the manufactured primer layer when coating at high speed.

The above polyurethane aqueous dispersion is in the form of a polyurethane aqueous dispersion in which polyurethane is dispersed in water, and may be a polyurethane aqueous dispersion having an average particle size of the dispersed particles of 80 to 110 nm, or 90 to 100 nm. If the average particle size of the dispersed particles in the polyurethane aqueous dispersion deviates from the above, the manufactured primer layer may become cloudy, causing a problem in which optical properties deteriorate.

For example, the polyurethane aqueous dispersion may have a solid content (NV) of 30 to 40 wt%, or 30 to 35 wt%, based on the total weight. When the solid content of the polyurethane aqueous dispersion is within the above range, the polyurethane aqueous dispersion has excellent storage stability and can be stored in a high solid content form without particle aggregation or precipitation. In addition, when the solid content of the polyurethane aqueous dispersion is less than the above range, there is a problem in that the amount of other compositions that can be used is limited due to the low solid content concentration and high water content, and when it exceeds the above range, workability such as weighing and storage stability may be deteriorated due to the high viscosity.

The above-mentioned water-based primer composition may contain 14 to 21 wt%, or 16 to 20 wt%, of a polyurethane aqueous dispersion based on the total weight of the primer composition. If the content of the polyurethane aqueous dispersion is less than the above range, there may be a problem of low adhesion due to insufficient binder amount, and if it exceeds the above range, the viscosity of the primer composition may be high, resulting in poor coating. At this time, the content of the polyurethane aqueous dispersion may be a content based on solid content.

In addition, the primer composition may include a polyurethane aqueous dispersion and a polyolefin imine aqueous solution in a weight ratio of 7:1 to 11:1, or 7.5:1 to 10:1. When the content of the polyurethane aqueous dispersion is less than the above range based on the content of the polyolefin imine aqueous solution, there may be a problem that the adhesion of the primer layer is insufficient due to insufficient polyurethane content, and when it exceeds the above range, there may be a problem that the ink suitability and ink fixation are deteriorated due to insufficient cationicity on the surface of the primer layer. At this time, the weight ratio of the polyurethane aqueous dispersion and the polyolefin imine aqueous solution may be a weight ratio based on the solid content of each component.

Polyolefin imine aqueous solution

The polyolefin imine aqueous solution acts as an auxiliary resin in a composition containing the same, and improves the adhesion of a primer layer manufactured from the same.

The above polyolefin imine has a cationic polar group and a hydrophobic group such as an olefin group, so it has a high bonding force with substances having different polarities, and particularly excellent adhesion to plastic materials. Accordingly, the present invention includes a cationic polyolefin imine as an auxiliary resin, so that it has the effect of improving the fixation of ink having an anion and the adhesion of other layers and the primer layer.

Specifically, the polyolefin imine aqueous solution has the main purpose of fixing pigments by utilizing cationic properties, and does not directly react with OH (hydroxyl group) or COOH (carboxyl group) contained in polyurethane, pigment dispersants, etc., but through the addition of an additional cross-linking agent such as an isocyanate compound, the amine group of the polyolefin imine can cross-link with the isocyanate group and the hydroxyl group or carboxyl group to increase the bonding strength between each layer.

Additionally, the polyolefin imine aqueous solution may be in the form of an aqueous solution in which polyolefin imine is dissolved in water.

For example, the polyolefin imine aqueous solution may have a solid content (NV) of 5 to 20 wt%, or 7 to 15 wt%, based on the total weight of the aqueous solution. When the solid content of the polyolefin imine aqueous solution is within the above range, the storage stability of the primer composition may be improved and workability may be excellent. In addition, when the solid content of the polyolefin imine aqueous solution is less than the above range, the viscosity of the composition may be excessively low, which may cause a problem in that the workability of the composition may be insufficient, and when it exceeds the above range, the viscosity of the composition may be excessively high, which may result in poor stability during the reaction and poor dispersion stability, which may cause coagulation over time.

The above polyolefin imine is a polymer of olefin imine, and may be an olefin imine having 2 to 5 carbon atoms, or a polymer of an olefin imine having 2 to 3 carbon atoms. Specifically, the polyolefin imine may be polyethylene imine.

In addition, the polyolefin imine may have a total content of secondary amine and tertiary amine of 60 to 80 wt%, or 65 to 75 wt%, based on the total amine content of primary amine, secondary amine, and tertiary amine. When the total content of secondary amine and tertiary amine is within the above range, the polyolefin imine has many branched forms, so that cationic charges are evenly distributed, thereby improving ink fixation and further enhancing the adhesion of the primer composition. In addition, when the total content of secondary amine and tertiary amine is less than the above range, there is a problem that the heat resistance of a primer layer manufactured therefrom is lowered, and when it exceeds the above range, the branched forms are large, so that the gelation property of the polyolefin imine is high.

The above polyolefin imine aqueous solution has a weight average molecular weight (Mw) of 1,000 to 90,000 g/mol on a solid basis. Specifically, the polyolefin imine aqueous solution may have a weight average molecular weight (Mw) of 5,000 to 80,000 g/mol, or 10,000 to 70,000 g/mol on a solid basis. When the weight average molecular weight on a solid basis of the polyolefin imine aqueous solution is within the above range, the adhesion between the primer layer and the transparent protective layer is excellent. In addition, when the weight average molecular weight on a solid basis of the polyolefin imine aqueous solution is less than the above range, the interlayer adhesion may be reduced, and when it exceeds the above range, the viscosity of the primer composition may be increased, which may cause coating defects.

In addition, the polyolefin imine aqueous solution may have a viscosity at 25°C of 30 to 150 cps, 30 to 100 cps, or 40 to 80 cps. If the viscosity of the polyolefin imine aqueous solution at 25°C is below the above range, there is a problem in that it does not exhibit appropriate adhesiveness as an auxiliary resin, and if it exceeds the above range, the viscosity of the primer composition is high, which may cause coating defects during gravure coating.

The above polyolefin imine may have an amine value of 17 to 20 mmol/g, or 18 to 19 mmol/g. When the amine value of the polyolefin imine is within the above range, the ink has an excellent effect of fixing to the manufactured primer layer. In addition, when the amine value of the polyolefin imine is below the above range, there is a problem that the ink suitability is low or the crosslinking site is insufficient due to insufficient cationicity, and when it exceeds the above range, on the contrary, the cationicity is too high and the pH is acidic, so that coagulation may occur when mixed with a polyurethane aqueous dispersion.

In addition, the polyolefin imine aqueous solution may have a pH of 7 to 13 or 10 to 12. If the pH of the polyolefin imine aqueous solution is below the above range, a shocking (coagulation) problem may occur with the anionic polyurethane aqueous dispersion when mixed with the polyurethane aqueous dispersion, and if it exceeds the above range, a problem of reduced ink fixation may occur.

The above-mentioned water-based primer composition may contain 1.6 to 2.4 wt%, 1.7 to 2.4 wt%, or 1.8 to 2.3 wt% of a polyolefin imine aqueous solution based on the total weight of the primer composition. If the content of the polyolefin imine aqueous solution is less than the above range, sufficient cationicity may not be provided to the surface of the primer layer, resulting in a problem of poor ink suitability, and if it exceeds the above range, the adhesive properties of the polyurethane may be inhibited, resulting in a problem of insufficient interlayer adhesiveness. At this time, the content of the polyurethane aqueous dispersion may be a content based on solid content.

water

The above water serves to control the viscosity of the primer composition and reduce the content of volatile organic compounds (VOCs) in the composition.

Additionally, the water may be, for example, ion-exchange water, deionized water, pure water, ultrapure water, distilled water, etc.

The content of the water can be appropriately adjusted in consideration of the fluidity, viscosity, etc. of the composition. Specifically, the water can be a residual amount satisfying 100 wt% based on the total weight of the aqueous primer composition. Specifically, the water can be included in an amount of 40 wt% or less, 10 to 40 wt%, or 20 to 30 wt% based on the total weight of the primer composition. When the content of the water in the composition is less than the above range, the coating workability of the primer composition at high speed is insufficient, resulting in a problem of uneven coating, and when it exceeds the above range, problems such as bleeding during coating may occur due to an excessive amount of water.

Additives

The above-mentioned aqueous ink composition may also contain additives that are typically applicable to primer compositions, such as surfactants and preservatives.

The above-described aqueous primer composition may have a solid content (NV) of 10 to 30 wt%, or 15 to 25 wt%, based on the total weight. When the solid content of the aqueous primer composition is within the above range, it is suitable for a high-speed gravure coating process, can form a primer layer of an appropriate thickness, and has an excellent adhesion effect. In addition, when the solid content of the aqueous primer composition is less than the above range, the adhesion is insufficient due to an insufficient amount of resin, and when it exceeds the above range, the coating thickness may be thick, which may cause a problem of lowering the optical properties of the printed layer.

The water-based primer composition according to the present invention as described above has excellent storage stability, transfer rate to a substrate layer, and printability, is suitable for digital printing, and is environmentally friendly because it is water-based and has a low VOC content.

Interior Film

In addition, an interior film according to the present invention includes a substrate layer; an ink layer formed on the substrate layer; a primer layer formed on the ink layer and formed from the water-based primer composition; and a transparent protective layer formed on the primer layer.

Substrate layer

The above-mentioned substrate layer can be used without any special restrictions as long as it is generally applicable to interior films or decorative films, and may include, for example, a vinyl chloride-based resin.

The above vinyl chloride resin may be at least one selected from the group consisting of polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), and vinyl chloride and a vinyl chloride copolymer containing a monomer copolymerized therewith.

The above-mentioned substrate layer may be a commercially available product that is typically applicable to interior films or decorative films, and may have, for example, an average thickness of 30 to 200 ㎛, or 50 to 150 ㎛.

Ink layer

The ink layer can be used without any special restrictions as long as it is a pigment ink composition that can be normally applied to interior films or decorative films.

The ink layer may be formed by a digital printing method. For example, the ink layer may be formed by printing on a primer layer by a digital printing method.

warrior film

A separate transfer film may be used to print the ink composition of the ink layer. At this time, the transfer film may include polyethylene terephthalate (PET) having excellent heat resistance and deformation rate.

When printing using a transfer film made of PET, the ink composition can be dried at a high temperature, thereby increasing the printing speed.

For example, the interior film can be manufactured by forming a primer layer on a transfer film using the water-based primer composition by a gravure or micro gravure method, forming an ink layer on the primer layer by a digital printing method, thermally transferring a first laminate including the transfer film, the primer layer, and the ink layer onto a substrate layer, removing the transfer film to manufacture a second laminate including the substrate layer, the ink layer, and the primer layer, and laminating a transparent protective layer on the primer layer of the second laminate.

Primer layer

The primer layer is formed from the water-based primer composition described above. The primer layer according to the present invention can increase the printability for water-based ink and provide high adhesion when laminating with a transparent protective layer after thermal transfer.

The above primer layer can be formed by a method generally applicable to interior films or decorative films, and can be formed by, for example, a gravure or micro gravure coating method.

In addition, the primer layer can be applied without any special limitation as long as it has a thickness that can be normally applied to interior films or decorative films, and for example, the average thickness can be 1 to 20 ㎛, or 2 to 10 ㎛. If the average thickness of the primer layer is outside the above range, the adhesive strength may be weakened, or the color development of the printed layer may be adversely affected due to the thick primer layer.

Transparent protective layer

The transparent protective layer can be used without any special restrictions as long as it is generally applicable to interior films or decorative films, and may include, for example, a vinyl chloride-based resin.

The above vinyl chloride resin may be at least one selected from the group consisting of polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), and vinyl chloride and a vinyl chloride copolymer containing a monomer copolymerized therewith.

The above transparent protective layer can be formed by a method that is typically applicable to interior films or decorative films, and for example, can be formed by a method of laminating on the primer layer. At this time, the lamination can be performed at 150 to 200° C. or 160 to 180° C., but is not limited thereto.

In addition, the transparent protective layer may use a commercially available product that is typically applicable to interior films or decorative films, and may have an average thickness of, for example, 50 to 200 ㎛, or 80 to 130 ㎛. If the average thickness of the transparent protective layer is outside the above range, a problem may occur in which the texture deteriorates because a deep embossing effect cannot be implemented, or the film price becomes high due to the thick thickness, resulting in poor economic feasibility.

The above interior film may have a 180° peel strength between the ink layer and the transparent protective layer of 1.5 to 3.0 kgf/inch, or 1.6 to 2.5 kgf/inch, as measured by a tensile tester.

The interior film according to the present invention as described above has excellent image resolution of the ink layer, excellent ink adhesion to the primer layer, and excellent interlayer adhesive strength, thereby achieving excellent productivity.

Hereinafter, the present invention will be described more specifically through examples. However, these examples are only intended to help understanding of the present invention, and the scope of the present invention is not limited to these examples in any way.

[Example]

Experimental examples 1 to 18. Preparation of water-based primer composition

A water-based primer composition was prepared by adjusting the composition as described in Tables 1 to 4.

Composition (weight%) Experimental Example 1 Experimental example 2 Experimental Example 3 Experimental example 4 Experimental Example 5 Polyurethane water dispersion-1 56.25 52.5 59.4 56.25 56.25 Polyurethane water dispersion-2 　 　 　 　 　 Polyurethane water dispersion-3 　 　 　 　 　 Polyurethane water dispersion-4 　 　 　 　 　 Polyurethane water dispersion-5 　 　 　 　 　 Polyacrylate emulsion 　 　 　 　 　 Polyethyleneimine aqueous solution-1 20 20 20 18 23 Polyethyleneimine aqueous solution-2 　 　 　 　 　 Polyethyleneimine aqueous solution-3 　 　 　 　 　 Polyethyleneimine aqueous solution-4 　 　 　 　 　 Cationic acrylic emulsion 　 　 　 　 　 cationic metal salt 　 　 　 　 　 Distilled water (D/W) 23.75 27.5 20.6 25.75 20.75 total 100.00 100.00 100.00 100.00 100.00 Polyurethane content (based on solids, weight%) 18.00 16.80 19.01 18.00 18.00 Polyethyleneimine content (based on solid content, weight%) 2.00 2.00 2.00 1.80 2.30

Composition (weight%) Experimental example 6 Experimental example 7 Experimental Example 8 Experimental Example 9 Experimental Example 10 Polyurethane water dispersion-1 　 56.25 43.12 70 62.5 Polyurethane water dispersion-2 60 　 　 　 　 Polyurethane water dispersion-3 　 　 　 　 　 Polyurethane water dispersion-4 　 　 　 　 　 Polyurethane water dispersion-5 　 　 　 　 　 Polyacrylate emulsion 　 　 　 　 　 Polyethyleneimine aqueous solution-1 20 　 15.3 24.8 　 Polyethyleneimine aqueous solution-2 　 20 　 　 　 Polyethyleneimine aqueous solution-3 　 　 　 　 　 Polyethyleneimine aqueous solution-4 　 　 　 　 　 Cationic acrylic emulsion 　 　 　 　 　 cationic metal salt 　 　 　 　 　 Distilled water (D/W) 20 23.75 41.58 5.2 37.5 total 100.00 100.00 100.00 100.00 100.00 Polyurethane content (based on solids, weight%) 18.00 18.00 13.80 22.40 20.00 Polyethyleneimine content (based on solid content, weight%) 2.00 2.00 1.53 2.48 0.00

Composition (weight%) Experimental Example 11 Experimental Example 12 Experimental Example 13 Experimental Example 14 Experimental Example 15 Polyurethane water dispersion-1 　 　 　 56.25 56.25 Polyurethane water dispersion-2 　 　 　 　 　 Polyurethane water dispersion-3 51.43 　 　 　 　 Polyurethane water dispersion-4 　 60 　 　 　 Polyurethane water dispersion-5 　 　 72 　 　 Polyacrylate emulsion 　 　 　 　 　 Polyethyleneimine aqueous solution-1 20 20 20 　 　 Polyethyleneimine aqueous solution-2 　 　 　 　 　 Polyethyleneimine aqueous solution-3 　 　 　 20 　 Polyethyleneimine aqueous solution-4 　 　 　 　 20 Cationic acrylic emulsion 　 　 　 　 　 cationic metal salt 　 　 　 　 　 Distilled water (D/W) 28.57 20 8 23.75 23.75 total 100.00 100.00 100.00 100.00 100.00 Polyurethane content (based on solids, weight%) 18.00 18.00 18.00 18.00 18.00 Polyethyleneimine content (based on solid content, weight%) 2.00 2.00 2.00 2.00 2.00

Composition (weight%) Experimental Example 16 Experimental Example 17 Experimental Example 18 Polyurethane water dispersion-1 　 56.25 56.25 Polyurethane water dispersion-2 　 　 　 Polyurethane water dispersion-3 　 　 　 Polyurethane water dispersion-4 　 　 　 Polyurethane water dispersion-5 　 　 　 Polyacrylate emulsion 39.13 　 　 Polyethyleneimine aqueous solution-1 20 　 　 Polyethyleneimine aqueous solution-2 　 　 　 Polyethyleneimine aqueous solution-3 　 　 　 Polyethyleneimine aqueous solution-4 　 　 　 Cationic acrylic emulsion 　 5 　 cationic metal salt 　 　 20 Distilled water (D/W) 40.87 38.75 23.75 total 100.00 100.00 100.00 Polyurethane content (based on solids, weight%) 18.00 18.00 18.00 Polyethyleneimine content (based on solid content, weight%) 2.00 2.00 2.00

The manufacturer, product name, and other characteristics of each component used in the above experimental examples are shown in Table 5 below. Mw is the weight average molecular weight, and Tg is the glass transition temperature.

ingredient note Polyurethane water dispersion-1 Polycarbonate type (solid content: 32 wt%, Tg: -20℃, average particle size of dispersed particles: 90 nm, viscosity (25℃): 2,500 cps) Polyurethane water dispersion-2 Polyether type (solid content: 30 wt%, Tg: 25℃, average particle size of dispersed particles: 100 nm, viscosity (25℃): 30 cps) Polyurethane water dispersion-3 Polyether type (solid content: 35 wt%, Tg: 70℃, average particle size of dispersed particles: 30 nm, viscosity (25℃): 300 cps) Polyurethane water dispersion-4 Polycarbonate type (solid content: 30 wt%, Tg: 90℃, average particle size of dispersed particles: 60 nm, viscosity (25℃): 30 cps) Polyurethane water dispersion-5 Polyether type (solid content: 25 wt%, Tg: -40℃, average particle size of dispersed particles: 130 nm, viscosity (25℃): 1,200 cps) Polyacrylate emulsion Solid content: 46 wt%, Tg: 17℃, Average particle size of dispersed particles: 150 nm, Viscosity (25℃): 1,900 cps Polyethyleneimine aqueous solution-1 Mw: 70,000 g/mol, viscosity (25℃): 60 cps, solid content: 10 wt%, amine value: 18 mmol/g, pH: 10 Polyethyleneimine aqueous solution-2 Mw: 10,000 g/mol, viscosity (25℃): 50 cps, solid content: 10 wt%, amine value: 18 mmol/g, pH: 11 Polyethyleneimine aqueous solution-3 Mw: 100,000 g/mol, viscosity (25℃): 200 cps, solid content: 10 wt%, amine value: 16 mmol/g, pH: 8 Polyethyleneimine aqueous solution-4 MW: 300 g/mol, Viscosity (25°C): 10 cps, Solid content: 10 wt%, Amine value: 21 mmol/g, pH: 13 Cationic acrylic emulsion Mw: 48,000 g/mol, Viscosity (25℃): 25 cps, Solid content: 40 wt%, Acid value: 130 mg KOH/g, Tg: 10℃, pH: 6.0 cationic metal salt CaCl ₂ aqueous solution (solid content: 10 wt%, pH: 6.9)

Test Example: Characteristic Evaluation

The properties of the aqueous primer composition of the experimental example were measured using the following methods, and the results are shown in Table 6.

(1) Primer layer appearance

The manufactured water-based primer composition was coated on a polyethylene terephthalate (PET) film (manufacturer: Toray Advanced Materials, product name: XG210, thickness: 50 ㎛) using a printing gravure corrector set to a #170 mesh gravure plate, and then dried at 120°C for 1 minute to manufacture a primer layer. Thereafter, the primer layer (thickness: 2 to 4 ㎛) was visually observed to evaluate coating defects such as bleeding, stains, and streaks.

(2) PVC transferability

After manufacturing a primer layer by the same coating method as in item (1), a water-based ink (manufacturer: Sanyo Chemical, product name: water-based pigment ink) was printed on the primer layer using a digital printer to form an ink layer. Thereafter, a colored PVC substrate film (manufacturer: Geumgang Enterprise, product name: KKP PRINT, thickness: 80 μm) was laminated on the ink layer and pressed using a hot press heated to 130°C, and then the PET film, which is a transfer film, was removed. Thereafter, the ink layer remaining on the PET film, which is a transfer film, was confirmed to evaluate the PVC transferability.

At this time, if the ink layer was completely transferred to the substrate layer, it was evaluated as good, and if the ink layer remained on the transfer film, it was evaluated as bad.

(3) Storage stability

After storing the water-based primer composition at 60°C for one week, the precipitation within the composition and the viscosity at 25°C were measured, and the storage stability was evaluated based on the following criteria.

Specifically, if there was no precipitation in the composition after storage and the viscosity at 25°C did not increase, it was evaluated as good, and if precipitation occurred in the composition or the viscosity at 25°C increased, it was evaluated as bad.

(4) Printing aptitude

In the same manner as in item (2), the ink layer printed with a digital printer was magnified and observed under a microscope to measure the diameter of the ink droplets that were deposited. At this time, if the diameter of the ink droplet was 30 to 50 ㎛, the printability was judged to be good, and if the diameter of the ink droplet was small or large, it was evaluated as poor.

(5) Peel strength

In item (2), a PVC transparent protective layer (manufacturer: Geumgang Enterprise, product name: KKP DECO, thickness: 110 ㎛) was laminated on a printed matter specimen transferred from a transfer film to a colored PVC substrate film, and a hot press was used to heat laminate at 170° C. to manufacture an interior film sample. Thereafter, the interior film sample was subjected to 180° peeling between the ink layer and the PVC transparent protective layer using a tensile tester (Universal Testing Machine, manufacturer: SALT, model name: ST-1003) to measure the strength.

　 appearance PVC transferability Printability Peel strength
(kgf/inch) Storage stability Experimental Example 1 Good Good Good 2 Good Experimental example 2 Good Good Good 1.6 Good Experimental Example 3 Good Good Good 2.1 Good Experimental example 4 Good Good Good 1.9 Good Experimental Example 5 Good Good Good 2 Good Experimental example 6 Good Good Good 1.6 Good Experimental example 7 Good Good Good 2.1 Good Experimental Example 8 Good Good error 1.1 Good Experimental Example 9 Defective (coating line occurs) Good Good 2.2 Bad (thickening) Experimental Example 10 Good Good Defective (ink shrinkage) Unmeasured
(Printing error) Good Experimental Example 11 Good error Good 0.1 Good Experimental Example 12 Good error Good 0.1 Good Experimental Example 13 Good error Good 0.3 Good Experimental Example 14 Defective (coating line occurs) error error 1.3 Good Experimental Example 15 Defective (bleeding) Good Good 0.1 Bad (thickening) Experimental Example 16 Good error error 0.1 Good Experimental Example 17 Defective (uneven) error error 0.4 Defective (sedimentation) Experimental Example 18 Defective (uneven) error Good 1.3 Defective (sedimentation)

As shown in Table 6, the compositions of Experimental Examples 1 to 7 had excellent storage stability, and the appearance of the primer layer manufactured therefrom, transferability to a PVC film, and printability of ink were excellent, and the interlayer adhesion was excellent, resulting in excellent peel strength.

On the other hand, Experimental Example 8, which contained a small amount of polyolefin imine aqueous solution, had very poor printability.

In addition, Experimental Example 9 including an excessive amount of polyurethane aqueous dispersion, Experimental Example 15 including an aqueous polyethyleneimine solution-4 having a small weight average molecular weight, and Experimental Examples 17 and 18 including a cationic acrylic emulsion or a cationic metal salt instead of a polyolefin imine aqueous solution had poor appearance of the primer layer, poor storage stability, increased viscosity, and poor workability. In particular, Experimental Example 15 had poor peel strength, Experimental Example 17 had poor PVC transferability, printability, and peel strength, and Experimental Example 18 had poor PVC transferability.

Experimental example 10, which did not include a polyolefin imine solution, had poor printability and peel strength.

In addition, Experimental Examples 11 and 12 including polyurethane aqueous dispersion-3 or polyurethane aqueous dispersion-4 having a high glass transition temperature and Experimental Example 13 including polyurethane aqueous dispersion-5 having a low glass transition temperature had insufficient PVC transferability.

Experimental Example 14, which included a polyethyleneimine aqueous solution-3 having a large weight average molecular weight, had poor appearance characteristics due to the formation of a coating line in the primer layer formed by the high viscosity of the primer composition, and poor PVC transferability and printability.

In addition, Experimental Example 16, which included a polyacrylate emulsion instead of a polyurethane aqueous dispersion, had poor PVC transferability, printability, and peel strength.

Claims (6)

Containing a polyurethane aqueous dispersion, a polyolefin imine aqueous solution and water,
The above polyurethane aqueous dispersion has a glass transition temperature of -25 to 30°C.
The above polyolefin imine aqueous solution is an aqueous primer composition having a weight average molecular weight of 1,000 to 90,000 g/mol based on solid content. In claim 1,
An aqueous primer composition wherein the polyurethane aqueous dispersion has a viscosity of 10 to 3,000 cps at 25°C and an average particle size of the dispersed particles of 80 to 110 nm. In claim 1,
An aqueous primer composition wherein the polyolefin imine aqueous solution has a viscosity of 30 to 150 cps at 25°C, a pH of 7 to 13, and an amine value of 17 to 20 mmol/g. In claim 1,
An aqueous primer composition comprising a polyurethane aqueous dispersion and a polyolefin imine aqueous solution in a weight ratio of 7:1 to 11:1 based on the solid content. substrate layer;
An ink layer formed on the above substrate layer;
A primer layer formed on the ink layer and formed from a water-based primer composition according to any one of claims 1 to 4; and
An interior film comprising a transparent protective layer formed on the primer layer. In claim 5,
The above primer layer has an average thickness of 1 to 20 ㎛,
The interior film above is an interior film having a 180° peel strength of 1.5 to 3.0 kgf/inch between the ink layer and the transparent protective layer using a tensile tester.