Oil-based ink composition

Abstract

The oil-based ink composition of the present invention is an oil-based ink composition containing: propylene glycol monomethyl ether, a resin, a hydroxy acid ester having a boiling point of 150°C or higher, an auxiliary solvent, and a floating type evaporation aluminum pigment, and the aforementioned auxiliary solvent is capable of dissolving the aforementioned resin and has a higher boiling point than the aforementioned hydroxy acid ester.

Description

Technical Field

[0001] This invention relates to oil-based ink compositions. Background Technology

[0002] In the past, ink compositions utilizing aluminum pigments have been used for decorative purposes in fields such as painting. Ink films using the aforementioned ink compositions can have an appearance that is both metallic in sheen (metallic color) and excellent gloss like a mirror (mirror finish).

[0003] Patent document 1 discloses an ethanol-based metallic color ink composition containing aluminum powder, ethanol, and ethanol-soluble rosin-modified maleic acid resin.

[0004] Patent document 2 discloses a glossy ink composition for writing, characterized in that it is formulated as a mixture with a thickness of 0.01 to 10% by weight relative to the total ink amount. It is obtained by vapor-deposited aluminum flake powder with an average particle size of less than 50 μm.

[0005] In addition, it is known from patent documents 3 to 6 that, in order to suppress the whitening of the ink coating, the ink contains benzyl alcohol.

[0006] Furthermore, in fields such as drawing, airbrushes are used that disperse ink into a mist and blow this mist of ink onto paper or other materials to perform drawing. More specifically, various airbrushes have been proposed that attach writing instruments, spray air into the nib of a pen, and cause the ink seeping from the nib to disperse into a mist, which is then blown onto paper or other materials to perform drawing.

[0007] Patent document 7 discloses a spray gun unit comprising a spray gun and a writing instrument, which sprays an aqueous ink composition by means of air ejected from the spray gun. The writing instrument contains the aqueous ink composition, and the aqueous ink composition contains opacifying pigments and has a shear viscosity reduction index of 0.4 to 0.8 at a shear rate of 9.6 to 76.6 / s.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 4-342775

[0011] Patent Document 2: Japanese Patent Application Publication No. 2004-51673

[0012] Patent Document 3: Japanese Patent Application Publication No. 61-14271

[0013] Patent Document 4: Japanese Patent Application Publication No. 2006-308664

[0014] Patent Document 5: Japanese Patent No. 3864115

[0015] Patent Document 6: Japanese Patent No. 4118093

[0016] Patent Document 7: Japanese Patent Application Publication No. 2019-189671 Summary of the Invention

[0017] The problem the invention aims to solve

[0018] In this invention, a novel oil-based ink composition is provided that can produce a coating with high mirror-like finish.

[0019] Solution for solving the problem

[0020] The inventors conducted in-depth research and discovered that the above-mentioned problems can be solved by the following solution, thus completing the present invention. That is, the present invention is as follows:

[0021] <Scheme 1> An oil-based ink composition comprising: propylene glycol monomethyl ether, resin, hydroxy acid ester with a boiling point above 150°C, auxiliary solvent, and floating-type vapor-deposited aluminum pigment, and

[0022] The aforementioned auxiliary solvent can dissolve the aforementioned resin and has a boiling point higher than the aforementioned hydroxy ester.

[0023] <Scheme 2> The oil-based ink composition according to Scheme 1, wherein the aforementioned hydroxy ester is a lactate.

[0024] <Scheme 3> The oil-based ink composition according to Scheme 2, wherein the aforementioned lactate is ethyl lactate.

[0025] <Scheme 4> The oil-based ink composition according to any one of Schemes 1 to 3 further contains an alcohol with a boiling point below 100°C.

[0026] <Scheme 5> An oil-based ink composition according to any one of Schemes 1 to 4, wherein the aforementioned resin is at least one resin selected from the group consisting of rosin and ketone resin.

[0027] <Scheme 6> An oil-based ink composition according to any one of Schemes 1 to 5, wherein the aforementioned auxiliary solvent is benzyl alcohol.

[0028] <Scheme 7> A writing instrument filled with any one of the oil-based ink compositions described in Schemes 1 to 6.

[0029] <Solution 8> A spray gun unit comprising: the writing instrument described in Solution 7, and a spray gun,

[0030] The spray gun unit, by means of air ejected from the spray gun, enables the aforementioned oil-based ink composition of the aforementioned writing instrument to be dispersed.

[0031] The effects of the invention

[0032] According to the present invention, a novel oil-based ink composition can be provided that yields a coating with high mirror-like finish. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of an airbrush unit that incorporates a marker pen. Detailed Implementation

[0034] Oil-based ink compositions

[0035] The oil-based ink composition of the present invention is an oil-based ink composition containing: propylene glycol monomethyl ether, resin, hydroxy acid ester with a boiling point of 150°C or higher, auxiliary solvent, and floating-type vapor-deposited aluminum pigment, wherein the aforementioned auxiliary solvent can dissolve the aforementioned resin and has a boiling point higher than the aforementioned hydroxy acid ester.

[0036] Traditionally, inks using floating-type vapor-deposited aluminum pigments typically use propylene glycol monomethyl ether (PGM) as a solvent to dissolve the resin and benzyl alcohol as a slow-drying agent. However, in this process, the ink absorbs moisture from the atmosphere during drying. This moisture disperses in the ink's organic solvent, causing the resin in the ink to precipitate (become insoluble), which sometimes compromises the mirror-like finish. Furthermore, depending on the humidity level, the amount of moisture absorbed by the ink may increase, or the water may become less volatile, which can further facilitate resin precipitation.

[0037] In response to this, the inventors discovered that by using a hydrophilic hydroxy acid ester with a boiling point of 150°C or higher and a boiling point lower than that of the auxiliary solvent, a coating film with high mirror-like finish can be obtained. Specifically, the hydroxy acid ester has an affinity for the water remaining in the ink after PGM volatilization, thereby suppressing resin precipitation.

[0038] Furthermore, the aforementioned auxiliary solvents are substances with low volatility and that dissolve resins; therefore, even after PGM evaporates, residues remain, causing further resin dissolution. Based on this, water evaporates slowly before the auxiliary solvents evaporate, allowing the ink to dry in a water-free state, thus suppressing resin precipitation. This results in a higher mirror finish.

[0039] The oil-based ink composition of the present invention preferably further contains an alcohol with a boiling point below 100°C. Such an alcohol, with a boiling point below that of water, evaporates along with the water, further reducing the water content in the ink. As a result, resin precipitation is further suppressed, resulting in a higher mirror finish.

[0040] The technical features of the present invention will be described below.

[0041] Propylene glycol monomethyl ether

[0042] As a propylene glycol monomethyl ether (PGM), it can be used from commercially available sources.

[0043] The content of propylene glycol monomethyl ether can be 40% or more by mass, 45% or more by mass, 50% or more by mass, 55% or more by mass, or 60% or more by mass. Alternatively, it can be less than 95% by mass, less than 90% by mass, less than 85% by mass, less than 80% by mass, less than 75% by mass, less than 70% by mass, or less than 65% by mass.

[0044] <Resin>

[0045] As resins, polar resins such as ketone resins, maleic acid resins, terpene resins, terpene phenol resins, ester gums, alkyd resins, phenolic resins, rosin, polyvinylpyrrolidone, polyvinyl butyral, polyvinyl alcohol, and acrylic resins, as well as non-polar resins such as melamine resins, xylene resins, sulfonamide resins, nitrocellulose resins, and urea resins, and their derivatives can be used. They can be used alone or in combination.

[0046] In particular, when the oil-based ink composition of the present invention contains alcohols with boiling points below 100°C, polar resins, especially ketone resins and rosin, are preferably used. These resins are readily soluble in the aforementioned alcohols due to their polarity, and as a result, they are not easily affected by water; that is, water is unlikely to precipitate even if it is present. Consequently, a high mirror-like finish can be achieved even if trace amounts of water remain in the ink.

[0047] From the viewpoint of obtaining sufficient adhesion, the resin content in the oil-based ink of the present invention is preferably 1% or more by mass, 2% or more by mass, 3% or more by mass, or 5% or more by mass. In addition, from the viewpoint of preventing the ink viscosity from becoming excessively high, so as not to impair the writeability or the ejection properties of the airbrush, it is preferably 50% or less by mass, 45% or less by mass, 40% or less by mass, 35% or less by mass, 30% or less by mass, 25% or less by mass, 20% or less by mass, 15% or less by mass, 10% or less by mass, or 7% or less by mass.

[0048] Hydroxy esters

[0049] As hydroxy acid esters, hydroxy acid esters with a boiling point above 150°C and a boiling point lower than that of the auxiliary solvent can be used. Their boiling points can be below 190°C, below 180°C, below 170°C, or below 160°C. Because the boiling point of such hydroxy acid esters is lower than that of the auxiliary solvent, they evaporate faster than the auxiliary solvent during ink drying. Since the boiling point of hydroxy acid esters is higher than that of water, they evaporate even slower than water, thus allowing residual water to be removed from the ink.

[0050] As hydroxy acid esters, examples include glycolates, lactates, tartrates, glycerides, and hydroxybutyrates. Among these, lactates are preferred from a mirror-like perspective.

[0051] There are no particular limitations on lactic esters as long as their boiling point is lower than that of the auxiliary solvent. Examples of such lactic esters include ethyl lactate (boiling point 154°C), propyl lactate (boiling point 169°C), butyl lactate (boiling point 170°C), pentyl lactate (boiling point 226°C), and hexyl lactate (boiling point 245°C). From the viewpoint of mirror appearance, ethyl lactate is preferred.

[0052] From the viewpoint of achieving good mirror finish, the preferred content of hydroxy acid esters is 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.7% by mass or more, 1% by mass or more, 3% by mass or more, or 4% by mass or more. This content can also be 25% by mass or less, 20% by mass or less, or 15% by mass or less, 10% by mass or less, 7% by mass or less, or 5% by mass or less.

[0053] <Auxiliary Solvent>

[0054] As an auxiliary solvent, a solvent capable of dissolving the above-mentioned resin and having a boiling point higher than that of the above-mentioned hydroxy acid ester can be used. Here, "capable of dissolving the resin" means that the amount of resin dissolved relative to 100 ml of auxiliary solvent is, for example, 5 g or more, 10 g or more, 15 g or more, 20 g or more, 30 g or more, 40 g or more, 50 g or more, 70 g or more, 80 g or more, or 100 g or more.

[0055] Such auxiliary solvents are often used as slow-drying agents. The presence of these auxiliary solvents suppresses whitening of the coating film, thereby improving its mirror-like appearance.

[0056] Examples of solvents that can be used include 3-methoxy-1-butanol (boiling point 158°C), 3-methoxy-3-methyl-1-butanol (boiling point 174°C), benzyl alcohol (boiling point 205°C), phenylpropanediol (boiling point 243°C), diethylene glycol monophenyl ether (boiling point 245°C), 2-phenoxyethanol (boiling point 247°C), and benzyl glycol (boiling point 256°C). These are also commercially available.

[0057] From the viewpoint of achieving good mirror finish, the content of the auxiliary solvent in the oil-based ink of the present invention is preferably 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.7% by mass or more, 1% by mass or more, 3% by mass or more, or 4% by mass or more. This content may also be 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 7% by mass or less, or 5% by mass or less.

[0058] The difference in boiling point between the auxiliary solvent and the hydroxy acid ester can be above 10°C, above 20°C, above 30°C, above 40°C, or above 50°C. Alternatively, it can be below 150°C, below 130°C, below 110°C, below 100°C, below 90°C, below 80°C, below 70°C, or below 60°C.

[0059] <Aluminum Pigment>

[0060] The aluminum pigment is a floating-type vapor-deposited aluminum pigment. Here, in this invention, "floating-type aluminum pigment" refers to aluminum pigment arranged on the surface of the coated ink film. Furthermore, "vapor-deposited aluminum pigment" refers to aluminum pigment with a thickness of approximately 100 nm or less, obtained by peeling the vapor-deposited aluminum from the plastic film and then crushing the aluminum film to deposit it onto a plastic film, etc. This thickness can be 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, or 25 μm or more; and can be 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, or 35 μm or less.

[0061] It should be noted that this thickness refers to the value below 50% of the specified thickness in the cumulative degree distribution known as the cumulative pass curve, which is the average thickness referred to as h50. This average thickness can be measured, for example, using a scanning electron microscope.

[0062] As the aforementioned aluminum pigment, commercially available aluminum pigments that are floatable "evaporated aluminum pigments" can be used appropriately.

[0063] The average particle size of the aluminum pigment can be 100 nm or more, 200 nm or more, 300 nm or more, 500 nm or more, 700 nm or more, 1 μm or more, 2 μm or more, 3 μm or more, 5 μm or more, 7 μm or more, or 10 μm or more. Alternatively, it can be less than 30 μm, less than 25 μm, less than 20 μm, less than 15 μm, less than 10 μm, or less than 7 μm. Here, the average particle size used in this specification is appropriately selected based on the size of the aluminum pigment being targeted. For particles approximately less than 1 μm, the average particle size (D50) is based on the histogram of the scattering intensity distribution determined by dynamic light scattering. For particles 1 μm or more, the median particle size (D50) calculated from a volume reference using laser diffraction is used. Measurements based on dynamic light scattering can be performed, for example, using a DelsaMax CORE (Beckman Coulter). Laser diffraction-based determinations can be performed, for example, using a particle size distribution measuring device MT3300II (MicrotracBEL Corp.).

[0064] As commercially available aluminum pigments for use in oil-based inks, aluminum pigments in a form dispersed in a solvent can be used. The solvent can be propylene glycol monomethyl ether, alcohols with a boiling point below 100°C, auxiliary solvents, or solvents commonly used in coatings, such as mineral oils, toluene, xylene, and solvent naphtha.

[0065] From the viewpoint of achieving a good metallic luster, the content of the solid component of aluminum pigment in the oil-based ink of the present invention is preferably 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.7% by mass or more, 1% by mass or more, or 3% by mass or more. Furthermore, from the viewpoint of suppressing the clogging of the oil-based ink in the writing part of the writing instrument and suppressing the unevenness of the coating film, thereby achieving a good mirror effect, it is preferably 10% by mass or less, 7% by mass or less, 5% by mass or less, 3% by mass or less, 1% by mass or less, or 0.5% by mass or less.

[0066] <alcohol>

[0067] Alcohols are alcohols with a boiling point below 100°C. Their boiling points can be below 90°C, below 88°C, below 85°C, or below 83°C, and can be above 60°C, above 70°C, or above 75°C.

[0068] As the aforementioned alcohol, methanol (boiling point 64.7℃), ethanol (boiling point 78.4℃), isopropanol (boiling point 82.5℃), propanol (boiling point 97-98℃), sec-butanol (boiling point 99℃), tert-butanol (boiling point 82.4℃), etc., can be used, among which ethanol or isopropanol are preferred. Using these alcohols, due to their low boiling points, allows for good drying of the lines and provides a good mirror finish.

[0069] From the viewpoint of obtaining sufficient adhesion, the content of the alcohol in the oil-based ink composition of the present invention is preferably 1% or more by mass, 2% or more by mass, 3% or more by mass, 5% or more by mass, or 7% or more by mass. In addition, from the viewpoint of suppressing excessive increase in ink viscosity, so as not to impair writeability and spray gun ejection, it is preferably 50% or less by mass, 45% or less by mass, 40% or less by mass, 35% or less by mass, 30% or less by mass, 25% or less by mass, 20% or less by mass, 15% or less by mass, or 10% or less by mass.

[0070] <Other Ingredients>

[0071] Oil-based inks can contain various additives, such as antioxidants, fixatives, and non-drying agents. For example, tocopherol acetate can be used as an antioxidant.

[0072] Writing Tools

[0073] The writing instrument contains oil-based ink. The writing instrument may have an ink storage section, a writing section, and a holding section, in which case the oil-based ink may also be stored in the ink storage section.

[0074] The writing instrument may be a marker pen. Here, in this specification, "marker pen" means a pen having a mechanism that supplies ink stored in an ink reservoir to a resin writing part by means of capillary action, and also includes pens referred to as "signature pens" by those skilled in the art.

[0075] From the viewpoint of achieving good ink flow, the writing instrument of the present invention is preferably a valve-type marker pen that also has a valve between the ink storage part and the writing part.

[0076] Spray Gun Unit

[0077] The spray gun unit of the present invention includes: the writing instrument described above, and a spray gun.

[0078] The spray gun unit can disperse the aforementioned oil-based ink composition of the aforementioned writing instrument by means of air ejected from the aforementioned spray gun.

[0079] The spray gun unit 100, on which a writing instrument is mounted, may have any connecting member 130 for connecting the spray gun 110 and the writing instrument 120.

[0080] Spray gun unit 100, for example Figure 1 As indicated by the white blank arrow, air is sprayed from nozzle 112 toward the writing section 122 of the writing instrument 120, which can make the ink adhering to the writing section 122... Figure 1 The five arrows indicate that the writing extends from the writing section 122.

[0081] <spray gun>

[0082] like Figure 1 As shown, the spray gun 110 may include a nozzle 112 and a gas supply member 114. The nozzle 112 and the gas supply member 114 may be formed as a single unit, or they may be connected to each other by means of a hollow member such as a hose.

[0083] There are no particular limitations on the nozzle as long as it is a nozzle capable of spraying high-pressure gas onto the writing part of the writing instrument.

[0084] There are no particular limitations on the gas supply component, as long as it is a component capable of supplying high-pressure gas to the nozzle. The gas supply component can be the following: a component that sprays air by blowing air in from the mouth; a component that generates high-pressure gas by compressing and deforming the elastic part of a blower by hand; a component that reciprocates the piston of a pump formed by a piston and a barrel by hand; a component that uses a spray can filled with liquefied gas; a component that generates compressed air electrically; or a component that is formed by a high-pressure gas generating device, such as a high-pressure gas generating device consisting of an electric motor and a diaphragm connected to the electric motor by means of a mechanism that converts rotary motion into reciprocating motion, and that supplies high-pressure gas from the high-pressure air generating device to the nozzle.

[0085] <Connecting Components>

[0086] The connecting component is any component that connects the spray gun and the writing instrument. There are no particular restrictions on the connecting component as long as it is a component that physically connects the spray gun and the writing instrument.

[0087] Example

[0088] The present invention will be specifically described with reference to embodiments and comparative examples, but the present invention is not limited thereto.

[0089] The Making of Ink

[0090] <Example 1>

[0091] Using 1.2 parts by weight of floating-type vapor-deposited aluminum pigment (average particle size 12 μm, average thickness 30 nm), 20 parts by weight of ketone resin (Ketone resin K90, Arakawa Chemical Industry Co., Ltd.), 3.0 parts by weight of ethyl lactate (boiling point 154°C) as a hydroxy acid ester, 10.0 parts by weight of ethanol (boiling point 78.4°C), 5.0 parts by weight of benzyl alcohol (boiling point 205°C) as an auxiliary solvent, 0.5 parts by weight of tocopherol acetate (Riken E acetate 960, RIKEN VITAMIN CO.,LTD.), and 60.3 parts by weight of propylene glycol monomethyl ether (PGM, Dowanol PM) as an organic solvent, 100 parts by weight of oil-based ink of Example 1 were prepared.

[0092] <Examples 2-9 and Comparative Examples 1-8>

[0093] As shown in Tables 1-3, the types and contents of each component were changed. Otherwise, the oil-based ink compositions of Examples 2-9 and Comparative Examples 1-8 were prepared in the same manner as in Example 1.

[0094] Details of the other components mentioned in Table 1 are as follows:

[0095] Floating flake aluminum pigment: 0870MS (Toyo Aluminum Co., Ltd., 70% solids, average particle size 10μm)

[0096] Rosin: PINECRYSTAL KE-604 (Arakawa Chemical Industry Co., Ltd.)

[0097] Evaluation of Mirror Imagery

[0098] The prepared oil-based ink composition of Example 1 was filled into the ink reservoir of a valve-type marker (PC-3M, Mitsubishi Pencil Co., Ltd.). Using this marker, writing was performed on a polystyrene plastic plate at a temperature of 25°C and humidity of 70%. The appearance of the lines was visually evaluated.

[0099] The oil-based ink compositions of Examples 2-9 and Comparative Examples 1-8 were also evaluated in the same manner.

[0100] The evaluation criteria are as follows:

[0101] A: The coating exhibits a strong mirror-like effect.

[0102] B: The coating gives a mirror-like appearance.

[0103] C: The coating is slightly darker, and the mirror effect is weaker.

[0104] D: The coating is significantly darker, and the mirror effect becomes quite weak.

[0105] E: No mirror effect in the coating.

[0106] The components and evaluation results of the embodiments and comparative examples are shown in Tables 1 to 3.

[0107] [Table 1]

[0108] Table 1

[0109]

[0110] [Table 2]

[0111] Table 2

[0112]

[0113] [Table 3]

[0114]

[0115] As can be understood from Tables 1-3, the oil-based ink composition of Example 1, which contains resin, hydroxy acid ester with a boiling point of 150°C or higher, auxiliary solvent, and floating-type vapor-deposited aluminum pigment, achieved a good mirror finish. The oil-based ink compositions of Examples 1 and 4, which also contain ethanol and use rosin or ketone resin as a polar resin, exhibit particularly good mirror finishes.

[0116] Explanation of reference numerals in the attached figures

[0117] 100 spray gun units

[0118] 110 spray gun

[0119] 112 nozzles

[0120] 114 Gas Supply Components

[0121] 120 writing instruments

[0122] 122 Writing Department

[0123] 130 connecting components

Claims

1. An oil-based ink composition comprising: propylene glycol monomethyl ether, resin, hydroxy acid ester with a boiling point above 150°C, auxiliary solvent, and floating-type vapor-deposited aluminum pigment. The auxiliary solvent can dissolve the resin and has a boiling point higher than that of the hydroxy ester. The auxiliary solvent has a content of 0.1% by mass or more and 25% by mass or less, and The content of the hydroxy ester is more than 0.1% by mass and less than 25% by mass.

2. The oil-based ink composition according to claim 1, wherein, The hydroxy ester is a lactate.

3. The oil-based ink composition according to claim 2, wherein, The lactate ester is ethyl lactate.

4. The oil-based ink composition according to claim 1 or 2, further comprising an alcohol with a boiling point below 100°C.

5. The oil-based ink composition according to claim 1 or 2, wherein, The resin is at least one resin selected from the group consisting of rosin and ketone resin.

6. The oil-based ink composition according to claim 1 or 2, wherein, The auxiliary solvent is benzyl alcohol.

7. A writing instrument filled with the oil-based ink composition according to any one of claims 1 to 6.

8. A spray gun unit comprising: the writing instrument as claimed in claim 7, and a spray gun. The spray gun unit, using air ejected from the spray gun, enables the oil-based ink composition of the writing instrument to scatter.

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