JP7483260B2 - Coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating - Google Patents

Description

The present invention relates to a coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating.

Paints are required to not only have excellent performance after the paint film is applied, but also to have excellent workability. For example, even if the quality of the paint film after application is excellent, if the paint workability is poor, such as requiring a lot of labor to apply or being difficult to apply, the value of the paint will be greatly reduced.

One of the important aspects of painting workability is the minimum amount of paint splatter (also known as spatter). When spray painting, for example, if the area to be painted and the area not to be painted are continuous on the surface of the workpiece, the non-painted area is masked with adhesive tape or similar to prevent paint from being applied to the non-painted area. Sheets are also installed to prevent paint from splattering in unintended directions and contaminating the surrounding area, but the time required for these steps can take up more than half of the total painting process. Furthermore, if there is a lot of paint splatter, the work efficiency of the painter decreases and the painting process can be delayed. In addition, paint that splatters on areas other than the target area is wasted, which increases the cost of paint.

For example, Patent Document 1 discloses a coating method in which paint is discharged from a nozzle head in the form of a liquid film or liquid column and applied to an object to be coated, with the aim of preventing atomized paint from scattering. However, while Patent Document 1 discloses that paint is applied to an object to be coated within a transition zone where the paint transitions from a liquid film or liquid column state to an atomized state, it does not disclose anything about the paint itself that can prevent paint from scattering.

Furthermore, Patent Document 1 points out the problem with spray painting, in that atomized paint particles are dispersed by air currents such as accompanying air currents. Thus, in spray painting, the paint that is sprayed is atomized and spreads out, so manual masking with appropriate force is required to ensure there are no gaps, and even if an automatic painting device is used, it is not very effective in shortening the painting process.

Therefore, preventing or reducing paint splashing can significantly shorten the process and reduce painting costs, thereby increasing the value of the paint.

JP 2015-107474 A

In addition, unlike painting with a roller or brush, when spray painting, there is a distance between the spray nozzle of the painting device and the object to be painted, so not only is it possible to prevent paint from scattering, but it is also important to be able to paint the desired area of the object with precision in order to increase the value of the paint.

The present invention aims to provide a paint composition for extrusion painting that suppresses or reduces paint scattering and has good painting accuracy.

The coating composition according to the present invention comprises:
A coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating,
The coating composition has a viscosity η1 of 40 Pa s or less when subjected to shear deformation at a shear rate of 1000 s ^-1 at 23°C for 30 seconds and then to shear deformation at a shear rate of 0.01 s ^-1 for 5 seconds;
The storage modulus of the coating composition at 23°C is 50 Pa or more, and
The coating composition has a steady-state viscosity η2 of 50 Pa s or more when measured by steady flow measurement of shear deformation at 23 ° C. and a shear rate of 0.01 ^s-1 .
The coating composition is for liquid film jet coating, liquid column jet coating, or liquid droplet jet coating. This makes it possible to suppress or reduce paint scattering in liquid film jet coating, liquid column jet coating, and liquid droplet jet coating, and to achieve good coating precision.

In one embodiment of the coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to the present invention, the steady-state viscosity value η2 is 50 to 500 Pa·s.

In one embodiment of the coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to the present invention, the viscosity η1 is 3 to 40 Pa·s.

In one embodiment of the coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to the present invention, the storage modulus is 50 to 400 Pa.

In one embodiment of the coating composition for liquid film discharge coating, liquid column discharge coating, or liquid droplet discharge coating according to the present invention, the coating composition for liquid film discharge coating, liquid column discharge coating, or liquid droplet discharge coating contains a resin component and a viscosity adjuster,
The viscosity modifier is at least one selected from the group consisting of alkali swelling type viscosity modifiers, urethane association type viscosity modifiers, and cellulose-based viscosity modifiers.

In one embodiment of the coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to the present invention, it is used for buildings.

The present invention provides a paint composition for extrusion coating that suppresses or reduces paint scattering and has good coating accuracy.

FIG. 1A is a schematic diagram showing how small droplets are formed during coating using a conventional liquid column ejection method. FIG. 1B is a schematic diagram showing how small droplets are formed during coating using a conventional liquid column ejection coating method. FIG. 1C is a schematic diagram showing how small droplets are formed during liquid column ejection coating using a conventional paint. FIG. 1D is a schematic diagram showing how small droplets are formed during liquid column ejection coating using a conventional paint.

The following describes embodiments of the present invention. These descriptions are intended to be illustrative of the present invention and are not intended to limit the present invention in any way.

In the present invention, two or more embodiments may be combined in any manner.

In the present invention, the paint and the paint composition can be used interchangeably.

In this specification, numerical ranges are intended to include the upper and lower limits of the range unless otherwise specified. For example, 50 to 500 Pa·s means 50 Pa·s or more and 500 Pa·s or less.

In the present invention, the viscosity η1 of the coating composition when it is subjected to shear deformation at a shear rate of 1000 s ⁻¹ for 30 seconds at 23° C. and then immediately thereafter to shear deformation at a shear rate of 0.01 s ⁻¹ for 5 seconds is determined by the method described in the Examples.

In the present invention, the storage modulus of the coating composition at 23°C is determined by the method described in the examples.

In the present invention, the steady-state viscosity value η2 of the coating composition in steady-state flow measurement of shear deformation at 23° C. and a shear rate of 0.01 s ⁻¹ is determined by the method described in the Examples.

In the present invention, the term "liquid film" refers to a coating composition in the form of a film or a surface. In the present invention, the term "liquid column" refers to a coating composition in the form of a column, line, or rod.

In the present invention, the term "liquid film ejection coating" refers to coating in which the coating composition is ejected in the form of a liquid film from an ejection port. In the present invention, the term "liquid column ejection coating" refers to coating in which the coating composition is ejected in the form of a liquid column from an ejection port. In the present invention, the term "droplet ejection coating" refers to coating in which a liquid film or liquid column of the coating composition is broken into droplets by turning the ejection on and off, and the droplets are applied while controlling the direction of each droplet.

Hereinafter, each of liquid film ejection coating, liquid column ejection coating, and liquid droplet ejection coating, or all three together, may be referred to simply as "ejection coating."

Hereinafter, the coating composition for ejection coating according to the present invention may be simply referred to as the "coating composition."

The drawings in this invention are drawn with a view to prioritizing understanding of the invention, and the dimensions, ratios, and distances of each component in the drawings are not accurate.

(Paint composition)
The coating composition according to the present invention comprises:
A coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating,
The coating composition has a viscosity η1 of 40 Pa s or less when subjected to shear deformation at a shear rate of 1000 s ^-1 at 23°C for 30 seconds and then to shear deformation at a shear rate of 0.01 s ^-1 for 5 seconds;
The storage modulus of the coating composition at 23°C is 50 Pa or more, and
The coating composition has a steady-state viscosity η2 of 50 Pa s or more when measured by steady flow measurement of shear deformation at 23 ° C. and a shear rate of 0.01 ^s-1 .
The coating composition is for liquid film discharge coating, liquid column discharge coating, or liquid droplet discharge coating.

Figures 1A to 1D are schematic diagrams showing how small droplets are formed during conventional liquid column spray painting using paint. Just before spraying, the spray outlet 1 is filled with paint 2 (Figure 1A). As the paint column (liquid column) 3 is sprayed, a paint thread 4 is formed between the sprayed paint column 3 and the paint 2 at the spray outlet (the paint remaining at the spray outlet or the paint filled in the spray outlet for the next spray) (Figure 1B). When the paint column 3 is sprayed further, the paint thread 4 breaks and the paint column 3 separates (Figure 1C). The broken paint thread 4 then breaks again, becoming small droplets 5 that fly off (Figure 1D).

For this reason, the inventors initially considered that by lowering the viscosity in steady flow measurement of shear deformation at a shear rate of 0.01 s ^-1 , which corresponds to the viscosity of the paint composition before discharge, and promoting the integration of the paint thread with the paint at the discharge port, the paint thread would not stretch in the discharge direction and the formation of small droplets could be suppressed. However, it was found that lowering the viscosity in the steady flow measurement makes it easier for the paint thread to integrate with the paint at the discharge port, but also reduces the viscosity of the paint at the discharge port, making the paint more likely to drip from the discharge port and causing the dripped paint to scatter.

Based on these results, the inventors next speculated that the following (1) and (2) would promote the integration of the paint thread with the paint at the discharge port, and the following (3) would be effective in suppressing the dripping of the paint from the discharge port:
(1) Reduce the viscosity of the paint thread.
(2) Increase the storage modulus of the paint yarn.
(3) Increase the viscosity of the paint at the outlet, not the viscosity of the paint thread.

Regarding the above (1), it is considered that the paint thread at the time of discharge is different from the paint before discharge, and the microstructure is broken, such as the entanglement of the paint molecular chains is reduced due to a shear rate of a certain level or more at the time of discharge. Therefore, assuming the viscosity of the paint thread in this state, the inventors set the viscosity η1 (hereinafter, sometimes simply referred to as "viscosity η1") when the paint composition is subjected to shear deformation at a shear rate of 1000 s ^{- 1} for 30 seconds at 23 ° C. and then to shear deformation at a shear rate of 0.01 s-1 for 5 seconds. By subjecting the paint to shear deformation at a shear rate of 1000 s ^-1 for 30 seconds, the paint becomes in the state of a broken paint thread at the time of discharge, and by further subjecting the paint composition to shear deformation at a shear rate of 0.01 s ^-1 for 5 seconds immediately after this 30 seconds (starting shear deformation at a shear rate of 0.01 s ^-1 at the time when the 30 seconds have elapsed), it is considered that the state of the paint thread immediately after the breakage can be reproduced or approximated. Then, by lowering the viscosity η1 which is assumed to be the viscosity of the paint thread immediately after the breakage, the integration of the paint thread with the paint at the discharge port is promoted.

Regarding (2) above, the paint thread during painting can be considered to be a viscoelastic body having an elastic component and a viscous component, and it is believed that increasing the elastic component (storage modulus) reduces the elongation of the paint thread. Increasing the storage modulus of this paint composition promotes the integration of the paint thread with the paint at the discharge port.

The inventors have discovered that by setting the viscosity η1 of the paint composition to 40 Pa·s or less and the storage modulus of the paint composition at 23°C (hereinafter, "storage modulus" refers to the value at 23°C unless otherwise specified) to 50 Pa or more, the paint at the discharge port and the paint thread become more easily integrated.

Regarding the above (3), since the sagging of the coating composition from the discharge port is the movement of the coating composition at the discharge port in the direction of gravity, it is believed that the sagging of the coating composition can be suppressed by increasing the viscosity of the coating composition that is stable with almost no shear deformation before and after discharge, rather than the viscosity of the coating thread immediately after breakage. The present inventors have found that the viscosity of the coating composition that is stable before and after discharge can be expressed as the viscosity when the viscosity reaches a steady value after more time has passed than the above viscosity η1, and that sagging of the coating composition can be suppressed by setting the steady value η2 of the viscosity in a steady flow measurement of shear deformation of the coating composition at 23°C and a shear rate of ^0.01 s-1 to 50 Pa·s or more.

The viscosity η1 of the coating composition of the present invention is 40 Pa·s or less. If the viscosity η1 is higher than 40 Pa·s, the coating at the discharge port and the coating thread cannot be integrated, and scattering of the coating cannot be suppressed or reduced. The viscosity η1 of the coating composition of the present invention is, for example, 1 to 40 Pa·s. In one embodiment of the coating composition of the present invention, the viscosity η1 is 40 Pa·s or less, 35 Pa·s or less, 30 Pa·s or less, 25 Pa·s or less, 20 Pa·s or less, 15 Pa·s or less, 10 Pa·s or less, 7 Pa·s or less, 5 Pa·s or less, or 3 Pa·s or less. In another embodiment of the coating composition of the present invention, the viscosity η1 is 1 Pa·s or more, 3 Pa·s or more, 5 Pa·s or more, 7 Pa·s or more, 10 Pa·s or more, 15 Pa·s or more, 20 Pa·s or more, 25 Pa·s or more, 30 Pa·s or more, or 35 Pa·s or more. In yet another embodiment of the coating composition of the present invention, the viscosity η1 is 5 to 40 Pa·s.

In one embodiment of the coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to the present invention, the viscosity η1 is 3 to 40 Pa·s.

In order to lower the viscosity η1 of the coating composition of the present invention, for example, a method of using a viscosity modifier with a small molecular weight, as described below, can be mentioned. Examples of viscosity modifiers with a small molecular weight include the UH series such as UH-140S, UH-752, UH-420, and UH-472 manufactured by ADEKA Corporation; and urethane association type viscosity modifiers such as SN Thickener 612 manufactured by San Nopco.

The storage modulus of the coating composition of the present invention is 50 Pa or more. If the storage modulus is less than 50 Pa, the coating at the discharge port and the coating thread cannot be integrated, and scattering of the coating cannot be suppressed or reduced. The storage modulus of the coating composition of the present invention is, for example, 50 to 700 Pa. In one embodiment of the coating composition of the present invention, the storage modulus is 50 Pa or more, 60 Pa or more, 70 Pa or more, 80 Pa or more, 90 Pa or more, 100 Pa or more, 130 Pa or more, 150 Pa or more, 170 Pa or more, 200 Pa or more, 230 Pa or more, 250 Pa or more, 300 Pa or more, 350 Pa or more, 400 Pa or more, 450 Pa or more, 500 Pa or more, 550 Pa or more, 600 Pa or more, 650 Pa or more, or 700 Pa or more. In another embodiment of the coating composition of the present invention, the storage modulus is 700 Pa or less, 650 Pa or less, 600 Pa or less, 550 Pa or less, 500 Pa or less, 450 Pa or less, 400 Pa or less, 350 Pa or less, 300 Pa or less, 250 Pa or less, 230 Pa or less, 200 Pa or less, 170 Pa or less, 150 Pa or less, 130 Pa or less, 100 Pa or less, 90 Pa or less, 80 Pa or less, 70 Pa or less, or 60 Pa or less. In yet another embodiment of the coating composition of the present invention, the storage modulus is 70 to 500 Pa.

In one embodiment of the coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to the present invention, the storage modulus is 50 to 400 Pa.

In order to increase the storage modulus of the coating composition of the present invention, for example, a method of using a viscosity modifier having a large molecular weight or a hard structure as described below can be mentioned. Examples of such viscosity modifiers include alkali swelling type viscosity modifiers such as SN Thickener 630 and 636 manufactured by San Nopco, Banster S100A manufactured by Chubu Saiden, Primal ASE-60 Thickener manufactured by Dow Chemical, and cellulose-based viscosity modifiers such as Cellosize QP4400 and 52000H manufactured by Dow Chemical. When increasing the storage modulus, cellulose-based viscosity modifiers are easier to increase the storage modulus than alkali swelling type viscosity modifiers.

The steady-state viscosity value η2 of the coating composition of the present invention is 50 Pa·s or more. If the steady-state viscosity value η2 is less than 50 Pa·s, sagging of the coating composition cannot be sufficiently suppressed, and splashing of the coating cannot be suppressed or reduced. The steady-state viscosity value η2 of the coating composition of the present invention is, for example, 50 to 1000 Pa·s. In one embodiment of the coating composition of the present invention, the steady-state viscosity value η2 is 50 Pa·s or more, 60 Pa·s or more, 70 Pa·s or more, 80 Pa·s or more, 90 Pa·s or more, 100 Pa·s or more, 150 Pa·s or more, 200 Pa·s or more, 250 Pa·s or more, 300 Pa·s or more, 350 Pa·s or more, 400 Pa·s or more, 450 Pa·s or more, 500 Pa·s or more, 550 Pa·s or more, 600 Pa·s or more, 650 Pa·s or more, 700 Pa·s or more, 750 Pa·s or more, 800 Pa·s or more, 850 Pa·s or more, 900 Pa·s or more, 950 Pa·s or more, or 1000 Pa·s or more. In another embodiment of the coating composition of the present invention, the steady-state viscosity value η2 is 1000 Pa·s or less, 950 Pa·s or less, 900 Pa·s or less, 850 Pa·s or less, 800 Pa·s or less, 750 Pa·s or less, 700 Pa·s or less, 650 Pa·s or less, 600 Pa·s or less, 550 Pa·s or less, 500 Pa·s or less, 450 Pa·s or less, 400 Pa·s or less, 350 Pa·s or less, 300 Pa·s or less, 250 Pa·s or less, 200 Pa·s or less, 150 Pa·s or less, 100 Pa·s or less, 90 Pa·s or less, 80 Pa·s or less, 70 Pa·s or less, or 60 Pa·s or less. In yet another embodiment of the coating composition of the present invention, the steady-state viscosity value η2 is 80 to 400 Pa·s.

In one embodiment of the coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to the present invention, the steady-state viscosity value η2 is 50 to 500 Pa·s.

In order to increase the steady-state viscosity value η2 of the coating composition of the present invention, for example, a method of using a viscosity modifier with a large molecular weight, as described below, can be mentioned. Examples of viscosity modifiers with a large molecular weight include alkali swelling type viscosity modifiers such as SN Thickener 630 and 636 manufactured by San Nopco, Banster S100A manufactured by Chubu Saiden, and Primal ASE-60 Thickener manufactured by Dow Chemical; and cellulose-based viscosity modifiers such as Cellosize QP4400 and 52000H manufactured by Dow Chemical.

In one preferred embodiment of the coating composition of the present invention, the viscosity η1 is 0.1 to 10 Pa·s, the storage modulus is 200 to 500 Pa, and the steady-state viscosity value η2 is 200 to 400 Pa·s. In another preferred embodiment of the coating composition of the present invention, the viscosity η1 is 5 to 40 Pa·s, the storage modulus is 70 to 500 Pa, and the steady-state viscosity value η2 is 80 to 400 Pa·s.

The coating composition of the present invention typically contains a resin component, a viscosity modifier, a pigment, and water and/or a solvent. The coating composition may also contain a crosslinker and other components.

Resin component The resin component functions as a coating film forming element. As the resin component, a resin component of a conventionally known coating composition can be used. As the resin component, for example, acrylic resin, polyester resin, alkyd resin, fluororesin, epoxy resin, polyurethane resin, polyether resin, etc. can be mentioned. In addition, as the resin component, for example, a polymer compound containing an inorganic component or consisting of an inorganic component, such as a silicone resin or an alkoxysilane condensate, can also be used. The resin component may be used alone or in combination of two or more kinds.

The resin component may be in an organic solvent form, an aqueous form (water-soluble, water-dispersible or emulsion), or a non-aqueous dispersion form.

The coating composition using the resin component may be, for example, a one-component type, a two-component mixture type consisting of a base agent and a curing agent, or a multi-component mixture type of three or more components.

The resin component can undergo a curing reaction by heating or at room temperature.

The amount of the resin component is not particularly limited and may be adjusted as appropriate. In one embodiment, the solid content of the resin component is 10 to 90 parts by mass or 10 to 60 parts by mass per 100 parts by mass of the total of the solid content of the resin component and the solid content of the pigment.

Viscosity Adjuster In the present invention, a known viscosity adjuster may be used to adjust the viscosity η1, storage modulus and steady-state viscosity value η2 of the coating composition. Examples of the viscosity adjuster include alkali swelling type viscosity adjuster, urethane association type viscosity adjuster, cellulose-based viscosity adjuster, amide-based viscosity adjuster, inorganic layered compound-based viscosity adjuster and aminoplast-based viscosity adjuster.

Examples of alkali swelling viscosity modifiers include polycarboxylic acid viscosity modifiers, polysulfonic acid viscosity modifiers, and polyphosphoric acid viscosity modifiers.

Commercially available alkali swelling viscosity modifiers include, for example, the SN Thickener series, such as SN Thickener 615, 630, 636, and 640 manufactured by San Nopco; the Primal series, such as Primal ASE-60 Thickener manufactured by Dow Chemical; and Banstar S100A manufactured by Chubu Saiden Co., Ltd. In one embodiment, the alkali swelling viscosity modifier is one or more selected from the group consisting of SN Thickener 630, 636, Banstar S100A, and Primal ASE-60 Thickener.

Examples of urethane association type viscosity modifiers include urethane modified polyether type viscosity modifiers.

Commercially available urethane associative viscosity modifiers include, for example, ADEKA Corporation's ADEKA NOL (registered trademark) UH series, such as ADEKA NOL (registered trademark) UH-140S, 420, 450, 472, 526, 540, 550, and 752; and SAN NOPCO's SN Thickener 612 and 665T. In one embodiment, the urethane associative viscosity modifier is one or more selected from the group consisting of ADEKA NOL (registered trademark) UH-140S, 420, 472, 752, and SN Thickener 612.

Examples of cellulose-based viscosity modifiers include crystalline cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.

Commercially available cellulose-based viscosity modifiers include, for example, the Ceolus® series, such as the Ceolus® RC series manufactured by Asahi Kasei Corporation; and the Cellosize series, such as Cellosize QP 4400 and 52000H manufactured by The Dow Chemical Company. In one embodiment, the cellulose-based viscosity modifier is one or more selected from the group consisting of Cellosize QP 4400 and Cellosize QP 52000H.

Examples of amide-based viscosity modifiers include fatty acid amides, polyamides, acrylamides, long-chain polyaminoamides, aminoamides, and salts thereof (e.g., phosphates).

Examples of inorganic layered compound viscosity adjusters include layered compounds such as montmorillonite, bentonite, and clay.

Examples of aminoplast viscosity modifiers include hydrophobically modified ethoxylate aminoplast associative viscosity modifiers.

The viscosity adjusters may be used alone or in combination of two or more.

In one embodiment of the coating composition according to the present invention, the viscosity modifier is one or more selected from the group consisting of alkali swelling type viscosity modifiers, urethane association type viscosity modifiers, and cellulose-based viscosity modifiers.

In one embodiment of the coating composition for liquid film discharge coating, liquid column discharge coating, or liquid droplet discharge coating according to the present invention, the coating composition for liquid film discharge coating, liquid column discharge coating, or liquid droplet discharge coating contains a resin component and a viscosity adjuster,
The viscosity modifier is at least one selected from the group consisting of alkali swelling type viscosity modifiers, urethane association type viscosity modifiers, and cellulose-based viscosity modifiers.

The content of the viscosity modifier in the coating composition of the present invention is not particularly limited and may be adjusted as appropriate.

The solid content of the viscosity modifier in the coating composition of the present invention is, for example, 0.1 to 3.0 parts by mass or 0.5 to 2.0 parts by mass per 100 parts by mass of the coating composition. In one embodiment of the coating composition of the present invention, the solid content of the viscosity modifier is 0.1 parts by mass or more, 0.3 parts by mass or more, 0.5 parts by mass or more, 0.6 parts by mass or more, 0.7 parts by mass or more, 0.8 parts by mass or more, 0.9 parts by mass or more, 1.0 parts by mass or more, 1.2 parts by mass or more, 1.4 parts by mass or more, 1.6 parts by mass or more, 1.8 parts by mass or more, 2.0 parts by mass or more, 2.2 parts by mass or more, 2.4 parts by mass or more, 2.6 parts by mass or more, 2.8 parts by mass or more, or 3.0 parts by mass or more per 100 parts by mass of the coating composition. In another embodiment of the coating composition of the present invention, the solid content of the viscosity modifier is 3.0 parts by mass or less, 2.8 parts by mass or less, 2.6 parts by mass or less, 2.4 parts by mass or less, 2.2 parts by mass or less, 2.0 parts by mass or less, 1.8 parts by mass or less, 1.6 parts by mass or less, 1.4 parts by mass or less, 1.2 parts by mass or less, 1.0 parts by mass or less, 0.9 parts by mass or less, 0.8 parts by mass or less, 0.7 parts by mass or less, 0.6 parts by mass or less, 0.5 parts by mass or less, or 0.3 parts by mass or less, relative to 100 parts by mass of the coating composition. In addition to the solid content of the resin component, pigment component, viscosity modifier, etc., the dispersion medium thereof; water and/or solvent are included. In the present invention, "100 parts by mass of the coating composition" means 100 parts by mass of the entire coating composition including these dispersion mediums; water and/or solvents.

Crosslinking agent The coating composition may contain a crosslinking agent. The crosslinking agent may be selected according to the curable functional group of the resin component. For example, the crosslinking agent may be a carbodiimide compound, a hydrazine compound, an amino resin, a (blocked) polyisocyanate compound, an amine compound, a polyamide compound, or a polycarboxylic acid compound. The crosslinking agent may be used alone or in combination of two or more kinds.

Pigments The pigment is not particularly limited, and known paint pigments can be used. Examples of pigments include color pigments such as titanium dioxide, carbon black, red iron oxide, and phthalocyanine blue; extender pigments such as calcium carbonate, talc, and mica; and rust-preventive pigments. The pigments may be used alone or in combination of two or more.

The coating composition of the present invention may be either an aqueous coating composition or a solvent-based coating composition. In one embodiment, the coating composition of the present invention is an aqueous coating composition. In another embodiment, the coating composition is a coating composition that satisfies the requirements of JIS A 6909.

In the present invention, a coating composition in which the dispersion medium contained in the greatest amount is water is called an aqueous coating composition. In the present invention, a coating composition in which the dispersion medium contained in the greatest amount is a solvent is called a solvent-based coating composition.

The total amount of paint solids in the coating composition of the present invention may be adjusted as appropriate and is not particularly limited. For example, the total amount of paint solids is 20 to 80 parts by mass relative to 100 parts by mass of the coating composition. In one embodiment of the coating composition of the present invention, the total amount of paint solids is 20 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, 50 parts by mass or more, 60 parts by mass or more, 70 parts by mass or more, or 80 parts by mass or more relative to 100 parts by mass of the coating composition. In another embodiment of the coating composition of the present invention, the total amount of paint solids is 80 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less relative to 100 parts by mass of the coating composition.

Water When water is used, conventionally known water can be appropriately selected and used. Examples of water include tap water, distilled water, deionized water, and purified water.

When water is used, the water content of the coating composition may be adjusted as appropriate. The water content of the coating composition is, for example, 20 to 80 parts by mass per 100 parts by mass of the coating composition. In one embodiment of the coating composition of the present invention, the water content is 20 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, 50 parts by mass or more, 60 parts by mass or more, 70 parts by mass or more, or 80 parts by mass or more per 100 parts by mass of the coating composition. In one embodiment of the coating composition of the present invention, the water content is 80 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less per 100 parts by mass of the coating composition.

Solvent When a solvent is used, it can be appropriately selected from solvents for conventionally known coating compositions. Examples of the solvent include alcohols such as methanol, ethanol, 2-propanol, and 1-butanol; esters such as ethyl acetate, butyl acetate, isobutyl acetate, ethyl propionate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; ethers such as diethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, dioxane, and tetrahydrofuran (THF); ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and the like. Examples of the solvent include glycols such as ethyl acetate, 1,3-butylene glycol, pentamethylene glycol, and 1,3-octylene glycol; amides such as formamide, N-methylformamide, dimethylformamide (DMF), dimethylacetamide, dimethylsulfoxide (DMSO), and N-methylpyrrolidone (NMP); ketones such as acetone, methyl ethyl ketone (MEK), methyl propyl ketone, methyl isobutyl ketone, acetylacetone, and cyclohexanone; aliphatic hydrocarbons such as mineral spirits and kerosene; aromatic hydrocarbons such as toluene, xylene, mesitylene, and dodecylbenzene; and halogenated solvents such as chloroform and dichloromethylene. The solvents may be used alone or in combination of two or more.

The coating composition of the present invention may be of the room temperature drying type or the heat drying type. In one embodiment, the coating composition of the present invention is of the room temperature drying type.

The coating composition of the present invention may be a one-component type or a two-component type.

When the coating composition is an aqueous coating composition, the content of the solvent may be adjusted as appropriate. For example, it is 0 to 15 parts by mass, preferably 0 to 10 parts by mass, per 100 parts by mass of the coating composition. In this case, for example, alcohols can be used as the solvent.

Other Components In addition to the above-mentioned components, the coating composition of the present invention may contain other components such as dispersants, film-forming assistants, antifreezing agents, crosslinking accelerators, curing agents, leveling agents, surface conditioners, defoamers, plasticizers, preservatives, antifungal agents, UV stabilizers, etc. Each of these other components may be used alone or in combination of two or more.

Uses of the coating composition The coating composition according to the present invention is a coating composition for at least one of liquid film discharge coating, liquid column discharge coating, and droplet discharge coating, i.e., liquid film discharge coating, liquid column discharge coating, and droplet discharge coating. In one embodiment, liquid film discharge coating does not include curtain flow coating. As described above, droplet discharge coating is a coating in which a coating composition of a liquid film or liquid column is broken into droplets by on and off of discharge, and the droplets are applied in a state in which the direction of each droplet is controlled. In contrast, spray coating and electrostatic coating are coating in which the coating composition is not on and off of discharge, but is broken by shear with air or centrifugal force, and the droplets are applied in a state in which the direction of each droplet is not controlled. Therefore, spray coating and electrostatic coating are not included in the "droplet discharge coating" of the present invention. In another embodiment, the coating composition according to the present invention is a coating composition for liquid film discharge coating or liquid column discharge coating.

As described above, the coating composition of the present invention suppresses or reduces paint scattering and has good coating accuracy, so it can be suitably used for coating with an automatic coating device such as a robot without masking, particularly for coating large objects such as buildings, objects to be coated outdoors, and objects to which electrostatic coating cannot be applied. With an automatic coating device such as a robot, the object to be coated and the coating pattern can be programmed in advance, and a coating material with good coating accuracy and no paint scattering can be used, so that coating can be easily performed with high accuracy even without masking, and a high-quality coating film can be formed, which has a great effect of shortening the coating process and reducing coating costs.

In one embodiment of the coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to the present invention, it is used for buildings.

In one embodiment, the coating composition of the present invention is for interior use. In another embodiment, the coating composition of the present invention is for exterior use.

- Method for preparing coating composition The method for preparing the coating composition is not particularly limited as long as the viscosity η1, storage modulus, and steady-state viscosity value η2 are within the specified ranges, and the coating composition can be prepared by mixing the above-mentioned resin components, pigments, viscosity modifiers, etc., by a conventionally known method. Also, a viscosity modifier or the like may be added to a commercially available coating material containing a resin component and a pigment to adjust the viscosity η1, storage modulus, and steady-state viscosity value η2 to within the specified ranges, to prepare the coating composition of the present invention.

- Method for preparing a coating film The method for preparing a coating film is not particularly limited, except that the coating composition of the present invention is applied using a discharge coating method. For example, a coating film can be prepared by applying the coating composition of the present invention by liquid film discharge coating, liquid column discharge coating, or liquid droplet discharge coating using a discharge coating device, jet dispenser, or the like described in Patent Document 1. The drying temperature after applying the coating composition may be appropriately adjusted depending on the solvent, etc. For example, when drying is required in a short time such as 10 seconds to 30 minutes, the temperature may be 60 to 200°C, and 80 to 160°C is preferable. When drying is not required in a short time, drying may be performed, for example, at room temperature.

Examples of coating devices capable of ejection coating include the ejection coating device of Patent Document 1; EcoPaintJet (registered trademark) manufactured by Durr; and jet dispensers. Jet dispensers include piezo jet dispensers that control ejection using a piezo element, and electromagnetic jet dispensers that control ejection using an electromagnetic valve. Examples of piezo jet dispensers include the Stream Jet E series manufactured by SSI JAPAN. Examples of electromagnetic jet dispensers include NOVADOT and JETTY manufactured by Sanei Tech Co., Ltd.

In the case of ejection coating in which the coating composition of the present invention is applied, the number of ejection ports of the coating device is not particularly limited, and may be, for example, one or two or more. The shape of the ejection port of the coating device is not particularly limited. For example, the cross-sectional shape of the ejection port may be a circle, an ellipse, a polygon (triangle, square, pentagon, hexagon, heptagon, octagon, etc.), a convex shape, a concave shape, or a combination of these.

The dimensions of the liquid film and liquid column when the coating composition is discharged as a liquid film or liquid column are not particularly limited, and may be adjusted appropriately depending on the movement speed of the discharge port, the distance between the discharge port and the substrate, the thickness of the coating film to be formed, etc.

The object on which a coating film is formed using the coating composition of the present invention is not particularly limited and can be selected appropriately. For example, the object includes the interior and exterior of the body of a vehicle such as an automobile or a railroad car, the body of an aircraft, the hull and superstructure (rigging) of a ship; the interior, exterior and roof of a building; furniture, fittings; window glass of a vehicle, an aircraft, a ship, a building, etc.; cases, containers, resin plates, films; housings and glass parts of electrical appliances such as displays, monitors, and refrigerators; coatings applied thereto; inorganic building materials such as various cements, ceramic building materials, lightweight foamed concrete, mortar, slate boards, roofs, tiles, and ALC; wood; various types of glass; metal substrates such as steel plates, aluminum, and stainless steel; and the like. As described above, in a preferred embodiment, the object on which a coating film is formed using the coating composition of the present invention is a building.

Thus, examples of articles having a coating film formed using the coating composition of the present invention include vehicles such as automobiles and railroad cars, aircraft, ships, buildings, furniture, fixtures, window glass, transparent bodies (including cases, containers, resin plates and films), electrical appliances, etc. In a preferred embodiment, the article having a coating film formed using the coating composition of the present invention is a building.

The present invention will be described in more detail below with reference to examples. However, these examples are intended to illustrate the present invention and are not intended to limit the present invention in any way.

The viscosity η1 of the coating composition was measured using a stress-controlled rheometer "MCR302" manufactured by Anton Paar, with a 50 mm cone plate, a gap of 0.1 mm, a measurement temperature of 23°C, and a shear deformation at a shear rate of 1000 s ^-1 for 30 seconds, followed immediately by a steady flow measurement at a shear deformation at a shear rate of ^0.01-1 for 5 seconds.

The storage modulus of the coating composition was measured using a stress-controlled rheometer "MCR302" manufactured by Anton Paar under the conditions of a 50 mm cone plate, a gap of 0.1 mm, a measurement temperature of 23°C, a linear strain, and an angular frequency of 100 s ^-1 .

The steady-state value η2 of the coating composition was measured using a stress-controlled rheometer "MCR302" manufactured by Anton Paar, with a 50 mm cone plate, a gap of 0.1 mm, a measurement temperature of 23°C, and a shear rate of ^0.01-1 .

Details of each component of the coating composition used in the examples are as follows.
Water: Tap water Resin component: Acrylic emulsion prepared in the Preparation Example described below White pigment: Titanium dioxide (solid content: 100%)
Extender pigment: calcium carbonate (solid content: 100%)
Additives: dispersant (manufactured by BYK Japan under the trade name "DISPERBYK-190"), defoamer (manufactured by Kyoeisha Chemical under the trade name "Aqualene 8020"), film-forming aid (manufactured by JNC under the trade name "CS-12"), and surface conditioner (manufactured by Kyoeisha Chemical under the trade name "Polyflow KL-100"). In Table 1, the dispersant, defoamer, film-forming aid, and surface conditioner are collectively referred to as additives. The solid content of the additives is 50%.
Viscosity modifier 1 (urethane association type viscosity modifier): Trade name "ADEKA NOL (registered trademark) UH-140S" manufactured by ADEKA Corporation (solid content: 30%, indicated as UH140S in Table 1)
Viscosity modifier 2 (urethane association type viscosity modifier): Trade name "ADEKA NOL (registered trademark) UH-752" manufactured by ADEKA Corporation (solid content: 30%, indicated as UH752 in Table 1)
Viscosity modifier 3 (urethane association type viscosity modifier): Trade name "ADEKA NOL (registered trademark) UH-420" manufactured by ADEKA Corporation (solid content: 30%, indicated as UH420 in Table 1)
Viscosity modifier 4 (urethane association type viscosity modifier): Trade name "ADEKA NOL (registered trademark) UH-472" manufactured by ADEKA Corporation (solid content: 30%, indicated as UH472 in Table 1)
Viscosity modifier 5 (urethane association type viscosity modifier): Trade name "SN Thickener 612" manufactured by San Nopco (solid content: 40%, indicated as SN612 in Table 1)
Viscosity modifier 6 (alkali swelling type viscosity modifier): Trade name "SN Thickener 630" manufactured by San Nopco (solid content: 30%, indicated as SN630 in Table 1)
Viscosity modifier 7 (alkali swelling type viscosity modifier): Trade name "Banstar S100A" manufactured by Chubu Saiden Co., Ltd. (solid content: 28%, indicated as S100A in Table 1)
Viscosity modifier 8 (alkali swelling type viscosity modifier): Trade name "SN Thickener 636" manufactured by San Nopco (solid content: 30%, indicated as SN636 in Table 1)
Viscosity modifier 9 (alkali swelling type viscosity modifier): Trade name "Primal ASE-60 Thickener" manufactured by Dow Chemical Company (solid content: 28%, indicated as ASE 60 in Table 1)
Viscosity modifier 10 (cellulose-based viscosity modifier): Trade name "Cellosize QP 4400" manufactured by The Dow Chemical Company (solid content: 100%, referred to as QP 4400 in Table 1)
Viscosity modifier 11 (cellulose-based viscosity modifier): Trade name "Cellosize QP 52000H" manufactured by The Dow Chemical Company (solid content: 100%, indicated as QP 52000H in Table 1)

As the ejection coating device, a piezo-jet coating device (Stream Jet E series) manufactured by SSI JAPAN was used.
The object to be painted was Maruman colored drawing paper Mitant 361-667P.

(Acrylic emulsion preparation example)
In accordance with the preparation of an acrylic emulsion described in paragraph [0078] of WO 2018/079212, an emulsion resin having a solid content of 49% by mass and a volume average particle size of 0.12 μm was obtained as a product. In Table 1, this is referred to as AcEm.

(Examples 1 to 7 and Comparative Examples 1 to 3)
A coating composition was prepared by mixing the components in the proportions (parts by mass) shown in Table 1. The viscosity η1, storage modulus, and steady-state viscosity value η2 of the coating composition were measured. The results are shown in Table 1.

(Evaluation of paint scattering and painting accuracy)
Each prepared coating composition was filled into a cartridge of a discharge coating device. The discharge nozzle of the coating device was arranged perpendicular to the paper surface to be coated. The distance between the discharge nozzle and the paper surface was set to 10 mm. Then, while moving the discharge nozzle in one direction parallel to the paper surface, liquid columns were discharged to coat the coating material at intervals of 0.6 mm, and 10 straight lines 100 mm in length were coated. The straight lines immediately after coating were visually observed, and the scattering of the coating material and coating accuracy were evaluated according to the following criteria.
・Paint scattering evaluation criteria Passed: Little or slight paint scattering was observed in areas other than the painted straight lines Failed: Paint scattering was observed or was significantly observed in areas other than the painted straight lines ・Paint painting accuracy evaluation criteria Passed: Little or slight jaggedness was observed on the painted straight line outline Failed: Jaggedness was observed or was significantly observed on the painted straight line outline

As shown in Table 1, the present invention provides a paint composition for extrusion coating that suppresses or reduces paint scattering and has good coating accuracy.

The present invention provides a paint composition for extrusion coating that suppresses or reduces paint scattering and has good coating accuracy.

1: Outlet 2: Paint 3: Paint column 4: Paint thread 5: Small droplet

Claims (6)

A coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating,
The coating composition has a viscosity η1 of 40 Pa s or less when subjected to shear deformation at a shear rate of 1000 s ^-1 at 23°C for 30 seconds and then to shear deformation at a shear rate of 0.01 s ^-1 for 5 seconds;
The storage modulus of the coating composition at 23°C is 50 Pa or more, and
The coating composition has a steady-state viscosity η2 of 50 Pa s or more when measured by steady flow measurement of shear deformation at 23 ° C. and a shear rate of 0.01 ^s-1 .
A coating composition for liquid film discharge coating, liquid column discharge coating, or liquid droplet discharge coating. The coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to claim 1, wherein the steady-state viscosity value η2 is 50 to 500 Pa·s. The coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to claim 1 or 2, wherein the viscosity η1 is 3 to 40 Pa·s. The coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to any one of claims 1 to 3, wherein the storage modulus is 50 to 400 Pa. Contains a resin component and a viscosity modifier,
The coating composition for liquid film discharge coating, liquid column discharge coating, or liquid droplet discharge coating according to any one of claims 1 to 4, wherein the viscosity modifier is one or more selected from the group consisting of an alkali swelling type viscosity modifier, a urethane association type viscosity modifier, and a cellulose-based viscosity modifier. A coating composition for liquid film ejection coating, liquid column ejection coating, or liquid droplet ejection coating according to any one of claims 1 to 5, which is for use on buildings.

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