KR20240078952A - Ink composition - Google Patents

Abstract

The present invention relates to an ink composition applicable to the inkjet method.

Description

Ink composition {INK COMPOSITION}

The present invention relates to an ink composition applicable to the inkjet method.

Gravure printing is mainly used as a printing method for manufacturing interior films, and various technologies for manufacturing interior films using this method have been proposed. For example, Patent Publication No. 2021-0077834 discloses an adhesive layer containing an acrylic copolymer, water, a tackifier, and an additive; A base layer containing a heat stabilizer and PVC resin; and an interior film including a printed layer containing a solvent having a boiling point of 120° C. or lower, and a method for manufacturing the same.

High-speed mass production is possible when using the gravure printing method, but it requires a lot of cost and time to produce copper plates for design changes, has limitations in expressing images vividly, and increases the time required to change processes and the possibility of safety accidents. there is a problem.

To solve this problem, a method of using a digital printer is being attempted. However, conventional ink compositions have problems such as insufficient compatibility with film materials, printing resolution, and adhesion strength.

The present invention provides an ink composition that has excellent compatibility with film materials (e.g., PVC, PET, etc.) and printing resolution, and exhibits adhesion strength capable of thermal lamination.

The present invention provides an ink composition including a pigment dispersion (A) including a pigment, a dispersant, and a solvent, a binder resin (B), and a solvent (C).

The present invention provides an ink composition that has excellent compatibility with film materials (e.g., PVC, PET, etc.) and printing resolution, and exhibits adhesion strength capable of thermal lamination. The ink composition according to the present invention is applicable to digital inkjet printing and can be used to manufacture interior films using a high-speed inkjet method, allowing interior films to be manufactured in a method with excellent efficiency and workability.

Additionally, the present invention provides a printing method using the above ink composition. By applying the print head and control system according to the present invention, excellent ink jetting properties can be secured, and products can be manufactured stably without affecting drying and smoothness when winding the material. The printing method of the present invention is applicable to interior films, wallpaper, glass, etc.

Hereinafter, the present invention will be described in detail. However, it is not limited to the following content, and each component may be variously modified or selectively mixed as needed. Accordingly, it should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

The “weight average molecular weight” used in this specification is measured by a common method known in the art, and can be measured, for example, by a GPC (gel permeation chromatograph) method. “Glass transition temperature” is measured by a common method known in the art, and can be measured, for example, by thermomechanical analysis (TMA) or differential scanning calorimetry (DSC). Functional values such as “acid value” are measured by common methods known in the art and can be measured, for example, by titration. “Particle size (volume average)” is measured by a common method known in the art and can be measured, for example, by laser light scattering (LLS). “Viscosity” is measured by a common method known in the art, and can be measured, for example, using a Brookfield viscometer (rotating spindle viscometer) at room temperature (25°C).

<Ink composition>

The ink composition of the present invention includes a pigment dispersion (A) containing a pigment, a dispersant, and a solvent, a binder resin (B), and a solvent (C).

Pigment dispersion (A)

The ink composition of the present invention includes a pigment dispersion (A) containing a pigment, a dispersant, and a solvent.

The pigment is not particularly limited, and both organic and inorganic pigments can be used, and pigments of any color can be used. For example, Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48(Ca), 48(Mn), 57(Ca), 57:1, 88, 112, 114, 122, 123, 144, 146, 149, 150 , 166, 168, 170, 171, 175, 176, 178, 179, 184, 185, 187, 202, 219, 245, Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50, etc. MAGENTA) Pigment; CYAN pigments such as Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:34, 15:4, 16, 18, 22, 25, 60, 65, 66 ; Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 167, YELLOW pigments such as 172 and 180; Pigment Black 7, carbon black, such as MCF88, No.2300, 2200 B, 900, 33, 40, 45, 52, MA7, 8, 100, etc. (Mitsubishi Chemical Company), Raven 5750, 5250, 5000, 3500 , 1255, 700, etc. (Colombia Carbon), Regal 400 R, 330 R, 660 R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, etc. (Cabot), Color Black FW1, BLACK pigments such as FW2, FW2V, FW18, FW200, S15, S160, S170, Printex 35, U, V, 140 U, Specual Black 6, 5, 4A, 4 (Degutsa) can be used. . These pigments can be used individually or in mixture of two or more types.

The pigment may be included in an amount of 1 to 15% by weight, for example, 3 to 7% by weight, based on the total amount of the ink composition.

The particle size (volume average) of the pigment in the pigment dispersion (A) may be 10 to 300 nm, for example, 50 to 200 nm. If the particle size of the pigment is less than the above-mentioned range, re-agglomeration between particles may occur or hiding power may be reduced, and if it exceeds the above-mentioned range, coloring power and discharge stability may be reduced.

For example, the pigment has a light resistance of grade 6 or higher, for example, grade 6 to 8, a heat resistance of 180 ° C. or higher, for example, 180 to 250 ° C., and a color difference change amount (△E) after an accelerated weathering test (QUV 1,000 hours) ) may be 1 to 5 or less, for example 1 to 3 or less. If the light fastness of the pigment is less than grade 6 or the amount of color difference exceeds the above-mentioned range, it may cause color changes depending on the indoor/outdoor exposure time of interior films and other decorative products, and if the heat resistance is less than 180 ℃, the transparent layer of the PVC upper body and the heat Lamination may cause color changes in the image.

In the present invention, the pigment is dispersed in a solvent using a polymer dispersant. The polymer dispersant serves to adsorb the pigment and stably disperse it in the solvent.

The dispersant may have an amine value of 1 to 100 mgKOH/g, for example, 1 to 50 mgKOH/g, and an acid value of 1 to 100 mgKOH/g, for example, 1 to 50 mgKOH/g. If the amine value and acid value of the dispersant are within the above-mentioned ranges, when dispersing the pigment, the dispersant may well adsorb to the surface of the pigment, thereby reducing the average particle size in the pigment dispersion and narrowing the distribution. Additionally, by providing electrostatic repulsion between particles, the storage stability of the dispersion is further improved. If the amine value and acid value of the dispersant are outside the above-mentioned range, the pigment adsorption of the dispersant decreases, the dispersibility decreases, the viscosity of the pigment dispersion increases, it becomes difficult to prepare a dispersion of the desired particle size, and the resistance of the ink film may decrease. there is.

The dispersant may have a weight average molecular weight of 1,000 to 60,000 g/mol, for example, 2,000 to 40,000 g/mol, and in another example, 2,000 to 30,000 g/mol. When the weight average molecular weight of the dispersant is within the above-mentioned range, compatibility with the dispersion solvent can improve and the stability of the pigment dispersion can be improved.

The dispersant may be a commercially available dispersant, such as a structured copolymer with a pigment-affinic group, such as BYKJET-9131; High molecular weight block copolymer with pigment-affinic group, such as DISPERBYK-161; High molecular weight polymers, such as BYKJET-9133, DISPERBYK-2200, 2205, TEGO Dispers 670, 685, Solsperse 13940, 32550, etc. can be used, and they can be used alone or in a mixture of two or more types. You can.

The solvents include propylene glycol methyl ether acetate (PMA), ethylene glycol n-butyl ether acetate (BGAc), ethylene glycol monobutyl ether (BGA), diethylene glycol diethyl ether (DEDG), and diethylene glycol methyl ethyl ether ( MEDG) etc. can be used. The solvent may be used alone or in combination of two or more types.

Based on the total amount of the pigment dispersion (A), 1 to 30% by weight of the pigment, for example 10 to 20% by weight, 1 to 30% by weight of the dispersant, for example 5 to 15% by weight, and the remaining amount of solvent. can do. If the content of the pigment is less than the above-mentioned range, the pigment content may be low and color development may be insufficient during coloring, and if it is more than the above-mentioned range, it may be difficult to prepare a stable nano-dispersion.

The mixing ratio of the pigment and the dispersant may be 1:0.2 to 1 weight ratio, for example, 1:0.4 to 0.8 weight ratio. If the mixing ratio of the dispersant to the pigment is less than the above-mentioned range, the dispersion time may increase and stability over time may be reduced due to the insufficient amount of dispersant adsorbed on the pigment, and if it exceeds the above-mentioned range, the viscosity of the dispersion increases. If a large amount of excess dispersant is generated, phase separation may occur and stability over time may deteriorate.

The pigment dispersion (A) may have a viscosity (25°C) of 5 to 50 cps, for example, 5 to 30 cps. If the viscosity of the pigment dispersion (A) exceeds the above-mentioned range, the viscosity may increase after manufacturing the ink, making it difficult to eject from the inkjet head.

The pigment dispersion (A) of the present invention has excellent stability over time. The pigment dispersion (A) may have a particle size change over time (room temperature, 2 weeks at 60°C) of less than ±20% of the initial value, and a change in viscosity over time (room temperature, 2 weeks at 60°C) of less than ±20% of the initial value.

The ink composition of the present invention may include 10 to 35% by weight, for example, 15 to 25% by weight of the pigment dispersion (A), based on the total weight of the ink composition. If the content of the pigment dispersion (A) is less than the above-mentioned range, color development after printing may be insufficient due to insufficient pigment content, and if it exceeds the above-mentioned range, it may cause an increase in ink viscosity and a decrease in aging stability.

Binder Resin (B)

The ink composition of the present invention includes a binder resin (B). The binder resin (B) is dried after printing to provide cohesion between pigments and increase adhesion to the printing paper. As the binder resin (B), polyester-modified polyurethane resin, polyether-modified polyurethane resin, polycarbonate-modified polyurethane resin, unsaturated polyester resin, etc. can be used. The above resins can be used alone or in combination of two or more types.

The polyester-modified polyurethane resin may be a polyester-modified aliphatic or aromatic polyurethane resin. For example, the polyester-modified polyurethane resin may be a polyester-modified aliphatic polyurethane resin. By including a polyurethane structure with a soft polymer nature, melting characteristics are improved, making it easier to penetrate into the uneven areas of the material layer during thermal lamination, improving adhesion, and improving the flexibility and elongation of the product. In addition, inclusion of a polyester structure inhibits intramolecular rotation, which makes the resin non-crystalline and improves sufficient adhesion to the substrate. In particular, when polyester-modified aliphatic polyurethane resin is used, the yellowing phenomenon is reduced and the weather resistance and color development of printed materials can be further improved.

The weight average molecular weight of the polyester-modified polyurethane resin is 50,000 to 100,000 g/mol, for example, 60,000 to 90,000 g/mol, and the glass transition temperature is -40 to 130 ℃, for example, -20 to 100 ℃, The hydroxyl value (OH value) may be 10 to 150 mgKOH/g, for example, 10 to 120 mgKOH/g. If the weight average molecular weight of the polyester-modified polyurethane resin is less than the above-mentioned range, the bonding strength may be weakened due to insufficient crosslinking, and the adhesion of the pigment to the printing paper (e.g., PVC) and the adhesion to the transparent layer (e.g., PVC) may be reduced. , if it exceeds the above-mentioned range, the resin density increases due to excessive crosslinking, which may cause an increase in the viscosity of the ink and head clogging. If the glass transition temperature of the polyester-modified polyurethane resin is below the above-mentioned range, resistance to scratches may be lowered and wear resistance may be reduced, and if it is above the above-mentioned range, flexibility may be reduced and pigment adhesion to printing paper (e.g., PVC) may be reduced. And the adhesion to the transparent layer (eg, PVC) may be reduced. If the hydroxyl value of the polyester-modified polyurethane resin is less than the above-mentioned range, the chemical bonding strength with the ink layer may be reduced, and if it is above the above-mentioned range, water resistance may be reduced.

The glass transition temperature of the unsaturated polyester resin is -20 to 100°C, for example, 0 to 80°C, and the hydroxyl value (OH value) is 10 to 150 mgKOH/g, for example, 10 to 120 mgKOH/g, The weight average molecular weight may be 50,000 to 100,000 g/mol, for example, 60,000 to 90,000 g/mol. If the glass transition temperature of the unsaturated polyester resin is below the above-mentioned range, the mechanical properties may be reduced, and if it is above the above-mentioned range, the penetration power of the resin into the ink layer may be reduced and the interlayer peeling power may be reduced, and the hydroxyl value may be reduced. If it is less than the above-mentioned range, the chemical bonding strength with the ink layer may be reduced, and if it is more than the above-mentioned range, water resistance may be reduced. If the weight average molecular weight of the unsaturated polyester resin is less than the above-mentioned range, the interlayer peeling force may be reduced, and if it is more than the above-mentioned range, the viscosity of the ink may be excessively high.

The ink composition of the present invention may include 1 to 10% by weight, for example, 1 to 5% by weight of the binder resin (B), based on the total weight of the ink composition. If the content of the binder resin (B) is less than the above-mentioned range, the amount of resin may be small and the bonding strength between the transparent upper layer (e.g., PVC) and the ink layer after thermal lamination may be weak, which may lower the peel strength, and if it exceeds the above-mentioned range, the ink viscosity may be low. may become too high, making it difficult to discharge from the head nozzle.

The mixing ratio of the binder resin (B) and the pigment dispersion (A) may be 1:2.5 to 5 weight ratio, for example, 1:3 to 4.5 weight ratio. If the mixing ratio of the pigment dispersion (A) to the binder resin (B) is less than the above-mentioned range, the amount of binder resin (B) capable of spreading the pigment dispersion (A) is insufficient, resulting in poor adhesion between the ink layer and the material. This decreases and peeling may easily occur, and if it exceeds the above-mentioned range, the viscosity of the pigment dispersion (A) increases, and if the viscosity range of the ink that can be printed is exceeded, the printability decreases and excessive binder resin (B) occurs. This may cause nozzle clogging.

Solvent (C)

The ink composition of the present invention includes a solvent (C). The solvent (C) includes ethylene glycol diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, (poly)ethylene glycol dialkyl ethers such as triethylene glycol diethyl ether and tetraethylene glycol dimethyl ether; (poly)propylene glycol dialkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and tetrapropylene glycol dimethyl ether; (poly)propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether; (poly)propylene such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, and dipropylene glycol monobutyl ether acetate. glycol monoalkyl ether monoalkyl ester; Ethylene Glycol Monomethyl Ether, Ethylene Glycol Monoethyl Ether, Ethylene Glycol Monobutyl Ether, Diethylene Glycol Monomethyl Ether, Diethylene Glycol Monoethyl Ether, Diethylene Glycol Monobutyl Ether, Triethylene Glycol Monomethyl Ether, Triethylene Glycol Mono (poly)ethylene glycol monoethers such as ethyl ether, triethylene glycol monobutyl ether, and tetraethylene glycol monobutyl ether; (poly)ethylene glycol monoesters such as ethylene glycol monomethyl acetate, ethylene glycol monoethyl acetate, ethylene glycol monobutyl acetate, diethylene glycol monomethyl acetate, and triethylene glycol monomethyl acetate; (poly)ethylene glycol diesters such as ethylene glycol diacetate, diethylene glycol diacetate, and triethylene glycol diacetate; Ethylene Glycol Monomethyl Ether Acetate, Ethylene Glycol Monoethyl Ether Acetate, Ethylene Glycol Monobutyl Ether Acetate, Diethylene Glycol Monomethyl Ether Acetate, Diethylene Glycol Monoethyl Ether Acetate, Diethylene Glycol Monobutyl Ether Acetate, Diethylene Glycol Propyl Ether (poly)ethylene glycol monoether monoesters such as acetate, triethylene glycol monobutyl ether, triethylene glycol ethyl ether acetate, and triethylene glycol butyl ether acetate; Butyl acetate (BA), etc. can be used. The solvent (C) may be used alone or in combination of two or more types.

The solvent (C) may be included in an amount satisfying 100% by weight of the total amount of the ink composition of the present invention. For example, based on the total weight of the ink composition, the solvent (C) may be included in an amount of 50 to 80% by weight, for example, 70 to 80% by weight. If the content of the solvent (C) is less than the above-mentioned range, it may become difficult to control the viscosity of the ink and dissolve the binder resin (B).

<Printing method>

The present invention provides a printing method using the above-described ink composition.

The printing may be an inkjet method, for example, a single-pass high-speed inkjet method. The single-pass high-speed inkjet method is a system in which the head of a digital printer is fixed and ink jetting occurs as the printed material passes.

The material to be printed may be interior film, wallpaper, glass, etc., and the material of the interior film may be vinyl media such as polyvinyl chloride (PVC) and polyethylene terephthalate (PET).

The nozzle size of the head of the digital printer may be 10 to 50 μm in diameter, and the frequency of the head may be 20 to 70 kHz. If the nozzle size of the head is less than the above-mentioned range, the shape of the ink drop may not be maintained consistently and a blowing phenomenon may occur, which may deteriorate printing quality and cause nozzle clogging. The frequency of the head affects the size of the ink droplet falling from the head nozzle. If the frequency is less than the above-mentioned range, the printing resolution may not be maintained and unprinted areas may occur. On the other hand, if the frequency exceeds the above-mentioned range, the size of the ink droplet increases, reducing printing reality, and adversely affecting the ink compatibility with the material, which may reduce the effect of inkjet implementation.

The printing method is controlled through an infeed and outfeed control system. The control system controls the unwinder and rewinder of the material to be printed, and as a result, the drying of the ink and the smoothness of the material can be maintained excellently.

For example, by installing an Edge Position Control (EPC) system in the unwinder and rewinder units to maintain fabric tension and prevent torquing, the smoothness of the material can be maintained during the printing process and coating process. For example, the unwinder can be equipped with an accumulator roll, dancer roll, and tension controller, and the smoothness of the printed material can be maintained through an EPC system that controls them. In addition, the rewinder is equipped with an accumulator roll, dancer roll, tension controller, and air-cooled and water-cooled cooler rollers, and the EPC system that controls them ensures drying of ink and material. Smoothness can be maintained.

For example, an interior film can be manufactured by printing the above-described ink composition using a single-pass high-speed inkjet method. The interior film may further include a primer layer on the ink layer. When a primer layer is coated on the ink layer, adhesion can be improved during subsequent embossing layer and lamination.

The primer composition forming the primer layer includes a primer resin and a solvent. The primer composition may be a one-component type or a two-component type containing a curing agent.

The primer resin may be vinyl copolymer resin, polyester resin, acrylic resin, polyurethane resin, etc., and the primer resin may be used alone or in a mixture of two or more types. For example, the primer resin may be a vinyl chloride-vinyl acetate copolymer containing 70 to 99% by weight of vinyl chloride and 1 to 30% by weight of vinyl acetate. The primer resin may have a weight average molecular weight of 3,000 to 200,000 g/mol and a glass transition temperature of -30 to 130°C.

The solvents include propylene glycol methyl ether acetate (PMA), ethylene glycol n-butyl ether acetate (BGAc), ethylene glycol monobutyl ether (BGA), gamma butyrolactone (G-BL), and diethylene glycol diethyl ether ( DEDG), diethylene glycol methyl ethyl ether (MEDG), ethyl acetate (EA), butyl acetate (BA), acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), toluene, alcohol, etc. there is. The solvent may be used alone or in combination of two or more types.

The primer composition may include 1 to 40% by weight and the remaining amount of solvent, based on the total amount of the primer composition.

The present invention will be described in more detail through examples below. However, the following examples are only intended to aid understanding of the present invention, and the scope of the present invention is not limited to the examples in any way.

[Manufacture example: Pigment dispersion (A) preparation]

Each component was mixed according to the composition shown in Table 1 below, the mixture was dispersed using a bead mill, and then filtered to prepare the pigment dispersion (A) of each preparation example.

Pigment: Magenta pigment (Hostaperm Pink E02, Clariant)

Dispersant: SOLSPERSE 32550, Lubrizol (amine value 10 mgKOH/g, acid value 7.75 mgKOH/g, Mw 2,600 g/mol)

Solvent: n-butyl ether acetate (BGAc)

[Physical property evaluation]

The physical properties of the pigment dispersion (A) of each preparation example were measured according to the method below, and the results are shown in Table 2 below.

dispersibility

The point at which particle size no longer decreases was measured and the dispersion time was evaluated.

average particle size

The average particle size immediately after dispersion was measured using laser light scattering (LLS).

stability over time

After the pigment dispersion (A) of each preparation example was left at room temperature and 60°C for two weeks, the average particle size was measured and the rate of change was calculated compared to immediately after dispersion.

As shown in Table 2, the pigment dispersion (A) of Preparation Example 1 according to the present invention had a short dispersion time and excellent stability over time. On the other hand, in the case of the pigment dispersion (A) of Preparation Example 2 in which the ratio of dispersant to pigment was less than the range of the present invention, the amount of dispersant was too small, so the average particle size after dispersion was large and stability over time was poor. On the other hand, the pigment dispersion (A) of Preparation Example 3, in which the ratio of dispersant to pigment exceeds the range of the present invention, had an excessive amount of dispersant, so the average particle size after dispersion was good, but stability over time was poor.

[Experimental example: Preparation of ink composition]

Ink compositions for each experimental example were prepared according to the compositions shown in Tables 3 and 4 below.

Pigment dispersion: Pigment dispersion of Preparation Example 1 (pigment concentration: 15%)

Binder Resin 1: Polyester modified aliphatic polyurethane resin (Mw 70,000 g/mol, Tg 25°C, OHv 90 mgKOH/g)

Binder Resin 2: Polyester modified aliphatic polyurethane resin (Mw 85,000 g/mol, Tg 50°C, OHv 50 mgKOH/g)

Binder Resin 3: Polyester modified aliphatic polyurethane resin (Mw 21,500 g/mol, Tg -24°C, OHv 100 mgKOH/g)

Binder Resin 4: Polyester modified aliphatic polyurethane resin (Mw 65,000 g/mol, Tg -19°C, OHv 170 mgKOH/g)

Binder Resin 5: Polyester modified aliphatic polyurethane resin (Mw 130,000 g/mol, Tg -20°C, OHv 73 mgKOH/g)

Binder Resin 6: Polyester modified aliphatic polyurethane resin (Mw 130,000 g/mol, Tg -45°C, OHv 0 mgKOH/g)

Binder Resin 7: Polyacrylic resin (Mw 26,000 g/mol, Tg 153 °C, OHv 90 mgKOH/g)

[Physical property evaluation]

The physical properties of the ink composition prepared according to each experimental example were evaluated by the following method. In addition, after printing using the ink composition of each experimental example, the physical properties were evaluated by the following method. The evaluation results are shown in Tables 5 and 6 below.

average particle size

The average particle size was measured using laser light scattering (LLS).

viscosity

It was measured using a viscometer (Brookfield Spindle Viscometer) at room temperature (25°C).

Printability

Using the ink composition of each experimental example, the print was printed at a width of 1,400 mm long for 1 hour, and the average nozzle dropout value of all heads (21 heads) corresponding to a single color unit was checked to evaluate print performance.

A: Average nozzle missing: 0-3

B: Average of 4-7 nozzles missing

C: Average of 8-11 nozzles missing

D: More than 12 nozzles missing on average

Specimen manufacturing (manufacturing of printed materials)

The ink composition of each experimental example was filled into a single-pass digital printer (Dimatix SG600 head, CMYK*2 rows, total of 172 heads, printing width 1,400 mm), and continuous beta was applied to the printed material (colored, PVC fabric with a thickness of 80,150 ㎛). A printout of each specimen was produced by printing (gray scale, 3-level output mode, frequency 45 kHz, single-pass continuous printing, productivity 50 m/min).

Adhesion (Cross cut Taping test )

Each printed specimen was subjected to a cross-cut test according to the ASTM D3359 international standard to confirm the adhesion between the ink and the material according to the binder resin.

water resistance

After exposing each printed specimen to a chamber with a temperature of 38 ℃ (±2 ℃) and 100% humidity for 24 hours, the condition of the specimen was observed with the naked eye to check whether blisters had occurred. Afterwards, adhesion was tested by cross cutting, and water resistance was evaluated according to the following standards.

[Evaluation standard]

○: No blister, adhesion 5B-4B

△: No blister, adhesion 3B

X: Blister generation and adhesion 2B-1B

Adhesion (peel strength)

Each printed specimen was covered with a PVC transparent top and thermally laminated at 170°C, and then the 180° peel strength between the printed layer and PVC was measured using a tensile tester.

As shown in Tables 5 and 6, the ink compositions of Experimental Examples 1-5 according to the present invention showed excellent physical properties in all measurement items. On the other hand, in Experimental Example 6, which used a binder resin outside the physical property range according to the present invention, adhesion, water resistance, and peel strength were reduced due to the low molecular weight of the binder resin (binder resin 3), and in Experimental Example 7, the binder resin (binder resin 4) was used. ) had low water resistance and peel strength due to its high hydroxyl value. On the other hand, in Experimental Example 8 using a high molecular weight binder resin (Binder Resin 5), the output properties decreased, and in Experimental Example 9 using a binder resin (Binder Resin 6) whose physical properties were all outside the scope of the present invention, the overall physical properties decreased. It was confirmed that it does.

In addition, the ink composition of Experimental Example 10 using a polyacrylic type binder resin (binder resin 7) instead of the binder resin of the present invention showed good printability, but the thermal lamination characteristics were deteriorated due to the high glass transition temperature of the binder resin. As a result, adhesion, water resistance, and peel strength were low. On the other hand, the ink composition of Experimental Example 11 without the addition of binder resin was found to have poor adhesion to the material and water resistance, and weak bonding strength with the transparent PVC upper paper, resulting in low peel strength after thermal lamination.

Claims (7)

An ink composition comprising a pigment dispersion (A) containing a pigment, a dispersant, and a solvent, a binder resin (B), and a solvent (C),
The mixing ratio of the pigment and dispersant in the pigment dispersion (A) is 1:0.2 to 1 weight ratio,
The binder resin (B) is a polyester-modified polyurethane resin, an unsaturated polyester resin, or a mixture thereof,
The polyester-modified polyurethane resin has a weight average molecular weight of 50,000 to 100,000 g/mol, a glass transition temperature of -40 to 130 ℃, and a hydroxyl value of 10 to 150 mgKOH/g,
An ink composition wherein the unsaturated polyester resin has a glass transition temperature of -20 to 100° C., a hydroxyl value of 10 to 150 mgKOH/g, and a weight average molecular weight of 50,000 to 100,000 g/mol. The ink composition according to claim 1, wherein the mixing ratio of the binder resin (B) and the pigment dispersion (A) is 1:2.5 to 5 by weight. The method of claim 1, wherein the pigment dispersion (A) has a particle size (volume average) of 10 to 300 nm, light resistance of grade 6 or higher, heat resistance of 180° C. or higher, and accelerated weathering test (QUV 1,000 hours). An ink composition having a color difference change (ΔE) of 1 to 5 or less. 2. The method of claim 1, wherein the dispersant comprises a structured copolymer having a pigment affinity group, a high molecular weight block copolymer having a pigment affinity group, a high molecular weight polymer, or a mixture thereof,
An ink composition wherein the dispersant has an amine value of 1 to 100 mgKOH/g, an acid value of 1 to 100 mgKOH/g, and a weight average molecular weight of 1,000 to 60,000 g/mol. The method of claim 1, wherein the viscosity (25°C) of the pigment dispersion (A) is 5 to 50 cps, the change in particle size over time (room temperature, 2 weeks at 60°C) is less than ±20% compared to the initial time, and the change in viscosity over time ( An ink composition that is less than ±20% of the initial value (2 weeks at room temperature, 60°C). The ink composition according to claim 1, comprising 1 to 30% by weight of the pigment, 1 to 30% by weight of the dispersant, and the remaining amount of solvent, based on the total amount of the pigment dispersion (A). The ink composition according to claim 1, comprising 10 to 35% by weight of the pigment dispersion (A), 1 to 10% by weight of the binder resin (B), and the remaining amount of solvent (C), based on the total amount of the ink composition.