JP2004099432A - Inkjet printing method on inorganic base material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of providing a product free from stain on an image and having excellent light resistance, adhesive property and durability even when an inorganic base material is colored by inkjet printing. <P>SOLUTION: In a method of inkjet printing on the inorganic base material using ink composed of an inorganic pigment, a dispersing medium and preferably, glass frit, after an ink receiving layer having non-fired glass frit is provided on a ceramic base material, the inkjet print is carried out and the ceramic base material is fired. <P>COPYRIGHT: (C)2004,JPO

Description

{Circle over (2)} The present invention relates to an image forming method using an ink jet system, and more particularly to a method for ink jet printing on an inorganic base material such as a ceramic.

2. Description of the Related Art A recording method using an ink-jet printing technique has been widely used.
2. Description of the Related Art In recent years, a medium used as a recording medium is not limited to paper, and image recording is performed on various materials such as films, plastics, ceramics, metals, and fabrics.

Dyes are used for various purposes as colorants for ink jet printing, but the dyes cannot sufficiently satisfy light resistance.
In order to satisfy light resistance, a pigment having excellent light resistance may be selected from pigments made of organic substances and used as a coloring material. In this case, the light resistance is remarkably improved as compared with the dye, but it is hardly sufficient as a coloring material for inorganic base materials such as ceramics having durability and light resistance.

As a method for solving the above problem, a method has been proposed in which an inorganic pigment having excellent light resistance is used as a coloring material, and an image is formed on a recording surface of a recording medium using an ink containing glass frit as a binder thereof. ing.
In this method, after printing an image on a recording medium, baking is performed to fuse the ink and the recording medium.
By using such a technique, decoration on an inorganic base material such as ceramics, enamel, glass and metal is performed by screen printing, brush writing (hereinafter, handwriting) or the like.

However, the number of colors and reproducibility are limited in the case of screens and handwriting, and the current situation is that screens cannot be used for only one point product such as a personal order.

Therefore, a coloring method using an inorganic pigment and an ink jet method has been recently studied.
By using the ink jet system, it is possible to improve the number of colors and reproducibility that can be expressed and to respond to personal orders.
However, the biggest disadvantage of the ink jet system is that the concentration range of the ink-containing component is narrow. That is, it is desirable that the ink has a high fluidity due to the structural properties of the ink jet head. In such a case, the components that can be contained in the ink and the amount thereof are often limited.

In the conventional silk-screening or hand-painting on an inorganic base material, a large amount of upper paint is mixed with a high-viscosity solvent, kneaded in a mortar or the like to prepare a high-viscosity dispersion, and then painted.
Therefore, the dispersion does not cause bleeding due to the low fluidity of the dispersion on the inorganic base material, and when the volatile components in the dispersion have volatilized, the dispersions of other colors are superimposed. Is also possible.

However, in the ink jet method, since the ink is a low-viscosity liquid, a bleeding phenomenon occurs on the inorganic base material when ejected and landed.

As a method to solve such bleeding phenomenon,
Has proposed an inorganic pigment ink jet printing method using a heat-fusible substance. In this method, the image after printing does not generate bleeding because the heat-fusible substance solidifies after discharge and landing, but the heat-fusible ink is re-melted because heat is applied to the base material during the firing step. There is a concern that bleeding will occur.

Furthermore, as a method of eliminating nozzle clogging,
Has proposed an ink obtained by adding a volatile material to an aqueous ink. However, while considering the volatility on the inorganic base material, there is a concern that ink drying on the surface of the printer head becomes a problem and the ejection stability is lacking. JP 2001-39008 A JP 2001-81363 A

The present invention provides an image forming method using an ink-jet method, which provides an image forming method on an inorganic base material that can form an image having good adhesion to a base material without blurring of the formed image. Is what you do.

Thus, the present inventors have conducted intensive studies on such a background of the problem, and as a result, using an inorganic pigment inkjet ink containing an inorganic pigment and a dispersion medium as essential components, providing an ink receiving layer having an unfired glass frit. By performing inkjet recording using the ink on the inorganic base material, no bleeding occurs even after printing and after firing, and a strong fired film is obtained, and the adhesion between the fired film and the base material is improved. It has been found that a remarkable effect of being excellent can be obtained.

Accordingly, the present invention provides an ink-receiving layer comprising an inorganic base and an unsintered glass frit as an essential component when performing ink-jet printing on an inorganic base using an ink containing an inorganic pigment and a dispersion medium (dispersion medium) as essential components. Is provided, followed by ink-jet printing, followed by baking, which is an ink-jet printing method for an inorganic substrate.
The ink receiving layer of the present invention contains glass frit as an essential component, but a layer containing an organic binder is more preferably used.
The ink used in the present invention contains an inorganic pigment and a dispersion medium as essential components, but an ink in which glass frit coexists is more preferably used.

Hereinafter, embodiments of the present invention will be described.
The substrate to which the method of the present invention is applied is an inorganic substrate, and specific examples thereof include glass, ceramics, enamel, tile, and metal. There is no particular limitation as long as the substrate is made of an inorganic material.
In the present invention, such an inorganic substrate is provided with an ink receiving layer containing unfired glass frit as an essential component. The particle size of the glass frit used as the ink receiving agent is not particularly limited, and any size can be used. used. Although the thickness of the ink receiving layer is not particularly limited, it is usually preferably about 1 to 1000 μm, and is usually adjusted according to the type of the ink or the inorganic base material.

Glass frit components used in the ink receiving layer include alkali metal compounds such as lithium carbonate, sodium carbonate, potassium carbonate, lead oxide and bismuth oxide, and alkaline earth metals such as barium carbonate, strontium carbonate, calcium carbonate and magnesium carbonate. , Zinc oxide, etc., neutral components include aluminum oxide and aluminum hydroxide, and acidic components include silicon oxide, boric acid, zirconium oxide, titanium oxide, and the like. In addition, mixed natural products such as feldspar, silica stone, borax, and kaolin These materials can be used alone or in the form of a composite to be dissolved and used as a frit.

In the ink receiving layer of the present invention, in addition to the unfired glass frit, if necessary, a dispersant, a heat stabilizer, an antioxidant, an antioxidant, a preservative, a pH adjuster, a defoamer, a wetting agent, Additives such as adhesives and penetrants, and water can be added to increase fluidity.

It is particularly preferable that the glass frit is attached to the inorganic substrate using an organic binder to form an ink receiving layer. By using a small amount of an organic binder to form an ink receiving layer with glass frit adhered to each other, a synergistic effect between subsequent ink-jet printing and baking allows the formed image to be free from bleeding and excellent in adhesion to a substrate. A quality image can be formed.

水溶 As the organic binder, a water-soluble or water-dispersible organic polymer is preferable, and particularly, a polymer having no metal atom in the molecular structure is preferable. This is because the metal atoms may be oxidized at the time of firing and the transparency of the ink receiving layer may be impaired.

Specific examples of these organic binders include starch, natural gum, vegetable protein, seaweed, casein, gelatin, and other natural polymers, ether-type cellulose, ester-type cellulose, ether-type starch, ester-type starch, and processed natural. Semi-synthetic polymers such as gums, polyvinyl alcohol, polyethylene glycol, polyvinyl acetate, polyvinyl butyrate resin, polyvinyl acrylate resin, polyvinyl methyl resin, cross-linked polyacrylic acid, sodium polyacrylate, polyacrylate, polyacrylamide, Examples include synthetic polymers such as sodium methacrylate, polybutadiene, polyurethane, polyester, and polylactic acid. These may be used alone or in combination of two or more.
These organic binders are preferably used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the glass frit.

As a method for forming the unfired glass frit ink receiving layer, any method can be adopted, and specific examples include a coating method, a laminating method, a spray method, and an ink jet method, and a method capable of forming a uniform continuous layer. preferable.
When the glass frit and the organic binder are used as an aqueous dispersion, the water-soluble concentration is set to 50 to 80%, and the viscosity is adjusted to 100 to 20,000 cps. This is preferable because the coatability when the frit ink receiving layer is formed is improved.

The applied amount of the ink receiving layer is preferably 2 to 10 times, particularly 2.5 to 4.5 times the maximum applied amount of the ink. When the applied amount of the ink receiving layer is less than twice the maximum applied amount of ink, bleeding may occur in the printed image, and when the applied amount of the ink receiving layer is more than 10 times the maximum applied amount of the ink. , There is a tendency that cracks easily occur in the glass film after firing.
Here, the application amount of the ink receiving layer refers to the weight (dry solid content) in a dry state in which 100% of water is evaporated. In addition, the maximum applied amount of ink is an applied amount of ink in a portion where the applied amount of ink per unit area is the largest because the applied amount of ink per unit area changes depending on the image to be printed. The liquid weight of the ink.

イ ン ク The ink composition used in the present invention contains an inorganic pigment and a dispersion medium as essential components, but it is preferable that a glass frit is also present.

As the inorganic pigment component used in the present invention, titanium oxide, zinc sulfide, black iron oxide, black copper oxide, black chromium oxide, yellow iron oxide, yellow nickel titanium, cadmium sulfide, selenium, selenide Cadmium, lead chromate, lead molybdate, red iron oxide, cobalt oxide, hydrated chromium oxide, chromium oxide, gold, lead antimony, nickel oxide, manganese oxide, neodymium oxide, erbium oxide, cerium oxide, aluminum oxide, aluminum, bronze , Mica, carbon black, calcium carbonate, barium sulfate, zinc oxide, antimony trioxide, cadmium mercury sulfide, navy blue, ultramarine blue, and the like. These can be used as a single product, a mixture, a double salt, or a complex salt.

In a preferred embodiment of the present invention, the glass frit used in the ink is, similarly to the glass frit component used in the ink receiving layer, an alkali metal compound such as lithium carbonate, sodium carbonate, potassium carbonate, lead oxide, bismuth oxide and the like. Alkaline earth metals include barium carbonate, strontium carbonate, calcium carbonate, magnesium carbonate, and zinc oxide. Neutral components include aluminum oxide and aluminum hydroxide, and acidic components include silicon oxide, boric acid, zirconium oxide, and titanium oxide. And feldspar, silica stone, borax, kaolin and the like, which are natural products composed of a mixed system. These materials can be dissolved alone or in a composite form and used as a frit.
Of course, it is also possible to use overpaints made from inorganic pigments and glass frit.

The medium in which the inorganic pigment and the glass frit in the ink composition used in the present invention are dispersed includes water, an organic solvent, a wax, or a mixture thereof, but is not limited thereto.
Further, when dispersing the inorganic pigment and the glass frit or the overpaint in the ink in the dispersion medium, various dispersants and surfactants can be used singly or in a mixed form.
Examples thereof include, as anionic surfactants, fatty acid soaps, alkyl succinates, alkyl benzene sulfonic acid sodium salts, alkyl naphthalene sulfonic acid sodium salts, alkyl sulfate sodium salts, polyoxyethylene alkyl ether sulfate sodium salts, dialkyl sulfo acids. Succinate sodium salt, sodium alkyl phosphate, polycarboxylic acid type polymer surfactant, alkyltrimethylammonium chloride, alkyldimethylbenzylammonium chloride as cationic surfactant, polyoxyethylene alkyl ether as nonionic surfactant, polyoxyethylene alkylether Oxyethylene alkyl allyl ethers, sorbitan fatty acid esters, and amphoteric surfactants include alkyl betaines and amido betaines. Here, as the anionic surfactant, not only a sodium salt but also any metal salt or ammonium salt can be used.
As a dispersant for a solid ink such as a hot-melt ink, a wax may be used as a dispersant in addition to the above-described dispersants.
Further, any other materials that exhibit a dispersing effect can be used.
It is also possible to add additives such as a heat stabilizer, an antioxidant, an anti-reduction agent, a preservative, a pH adjuster, an antifoaming agent, a wetting agent and a penetrant as needed.

The ink used in the present invention can be obtained by mixing the above materials, further dispersing the mixture using a disperser such as a roll mill, a ball mill, a colloid mill, a jet mill, a bead mill, and then performing filtration.
The ink of the present invention can be employed irrespective of a liquid ink, a solid ink such as a heat-meltable ink, or a photo-curable ink as long as it contains an inorganic pigment and a medium to be dispersed.

The inkjet printing apparatus used in the inkjet printing method of the present invention is not particularly limited.
By providing an ink receiving layer made of unfired glass frit on an inorganic base material according to the present invention, an image free from bleeding can be formed even after printing and firing.
One of the reasons is that the unfired glass frit is in the state of particles, so that in a layer formed by depositing them, a receiving layer having voids between the particles is formed, and therefore, even when the liquid ink is ejected and landed. And that the liquid component is efficiently absorbed by the receiving layer.
Further, by using the glass frit as the receiving layer, the glass frit in the ink and the glass frit in the receiving layer in a preferred embodiment are melt-mixed, so that a glass film having excellent adhesiveness can be formed.

In a preferred embodiment, the glass frit used in the ink and the glass frit used in the ink receiving layer are selected from substances having an appropriate coefficient of thermal expansion and a softening point depending on the base material to be colored. At the same temperature.
For example, when a glass having a softening point near 600 ° C. is used as the substrate, it is preferable to select a frit in the ink and a frit in the ink receiving layer having a softening point near or below 600 ° C. In this case, the firing temperature is preferably set to about 600 ± 100 ° C.
On the other hand, if the coefficient of thermal expansion of the frit is significantly different from that of the base material, cracks may occur in the glass melt layer after firing, or phenomena such as no adhesion may be observed, so care must be taken.

Regardless of the type of ink, the unfired glass frit ink receiving layer softens when it reaches the firing temperature after the low-boiling-point ink components are evaporated or burned by heat, and adheres to the substrate.
The glass frit ink receiving layer and the glass frit in the ink in the preferred embodiment hardly flow even when softened, so no bleeding phenomenon is observed, and the image obtained after firing has good adhesion to the substrate while maintaining sharpness. Thus, a strong glass film can be obtained.

Next, the present invention will be described with reference to examples, but the present invention is not necessarily limited to the examples.

A glass frit 12-3699 (softening temperature: 779 ° C., manufactured by Nippon Fellow) was used as an ink receiving layer, and dry dispersion was performed using a ball mill to an average particle size of about 10 μm. To 100 parts by weight of the glass frit powder, 10 parts by weight of hydroxypropylcellulose (organic binder: KLUCEL M, 10% aq product, manufactured by Aqualon (USA)) and 30 parts by weight of pure water were added, and kneaded in a mortar. After coating the tile (ceramics: glazed) using a screen, drying was performed at 110 ° C. for 10 minutes. The viscosity of the coating liquid was 8200 cps, and the applied amount (dry solid content) of the ink receiving layer was 32.7 g / m ² .
As ink Inorganic pigment and glass frit SUNSHINE AZURE (Cobalt oxide-based metal oxide + frit: Celdec)
20 parts by weight Dispersant Cariblon B (polycarboxylic acid type activator: Sanyo Chemical) 1 part by weight Wetting agent Polyethylene glycol 400 (Nippon Oil & Fat) 10 parts by weight After mixing 69 parts by weight of pure water, dispersing using a ball mill, and filtration. The impurities were removed to produce a homogeneous blue ink.
A recorded matter was obtained by using an inkjet printer as a method of applying the created ink to the tile provided with the ink receiving layer.
The printing conditions are as follows. The maximum application amount of the ink was 10 g / m ² .
After printing, firing was performed at 830 ° C. using an electric furnace for ceramics.
There was no bleeding in both the image after printing and the image after firing, and an image of a glass coating having good adhesion to the tile was formed.

(Printing conditions)
B) Nozzle diameter: 70 (μm)
B) Applied voltage: 50 (V)
C) Pulse width: 20 (μs)
D) Driving frequency: 1 (kHz)
E) Resolution: 180 (dpi)

〔Evaluation test〕
A) Bleeding: visual • No sharpness is maintained after printing and firing, and a sharp image is maintained.
・ Some bleeding has occurred after printing and firing. ・ （△）
・ Bleeding after printing and firing was so severe that no image was maintained at all (×)
I) Scratch resistance: JIS K5400 (8.4.2 Hand scratching method)
No damage at 2H hardness or more
No damage due to H hardness ・ ・ ・ ・ ・ ・ ○
No damage due to HB hardness ...
HB hardness or less and scratches ... ×
C) Peeling resistance: A cellophane tape was applied to the cured film, the tape was peeled off, and the state afterwards was checked.
The cured film does not peel off from the substrate ...
Cracks in the cured film or bubbles enter between the substrate and the cured film ...
The cured film is completely peeled off ... ×

Using a glass frit 12-3619 (softening temperature: 571 ° C., manufactured by Nippon Fellow) as an ink receiving layer, dry dispersion was carried out using a ball mill to an average particle size of about 10 μm. To 100 parts by weight of the glass frit powder, 10 parts by weight of polyethylene glycol 2000 (organic binder: PEG # 2000, manufactured by Nippon Oil & Fats) and 30 parts by weight of pure water were added, and the mixture was kneaded in a mortar, and glass (plate glass) was used with a screen. After the coating was performed, drying was performed at 110 ° C. for 10 minutes. The viscosity of the coating liquid was 30 cps, and the applied amount (dry solid content) of the ink receiving layer was 14.3 g / m ² .
As an ink Inorganic pigment TAROX R-516-L (iron oxide-based metal oxide: titanium industry)
5 parts by weight Frit 12-3619 15 parts by weight Dispersant Cariblon B (polycarboxylic acid type activator: Sanyo Kasei) 1 part by weight Wetting agent Polyethylene glycol 400 (Nippon Yushi) 10 parts by weight After mixing 69 parts by weight of pure water, a ball mill After the dispersion, the mixture was filtered to remove impurities to produce a homogeneous red ink.
A recorded matter was obtained by using an ink jet printer as a method of applying the prepared ink to the glass provided with the ink receiving layer.
The printing conditions are the same as in the first embodiment. The maximum application amount of the ink was 5 g / m ² .
After printing, firing was performed at 600 ° C. using an electric furnace for ceramics.

Using glass frit 01-4303 (softening temperature: 459 ° C., manufactured by Nippon Fellow) as an ink receiving layer, dry dispersion was carried out using a ball mill to an average particle size of about 10 μm. To 100 parts by weight of the glass frit powder, 2 parts by weight of carboxymethyl cellulose (organic binder: cellogen PR, 10% aq product, manufactured by Daiichi Kogyo Seiyaku) and 30 parts by weight of pure water were added, and the mixture was kneaded in a mortar, and the screen was screened. After performing coating on the aluminum plate used, drying was performed at 110 ° C. for 10 minutes. Incidentally, the viscosity of the coating liquid was 3400 cps, and the applied amount (dry solid content) of the ink receiving layer was 92.0 g / m ² .
As ink Inorganic pigment 42-701A (Cobalt oxide-based metal oxide: Nippon Fellow) 5 parts by weight Dispersant Cariblon B (polycarboxylic acid type activator: Sanyo Chemical) 1 part by weight Wetting agent Polyethylene glycol 400 (Nippon Yushi) 10 parts by weight After mixing 84 parts by weight of pure water, the mixture was dispersed using a ball mill, and then filtered to remove impurities to produce a homogeneous black ink.
A recorded matter was obtained by using an ink jet printer as a method of applying the prepared ink to an aluminum plate provided with an ink receiving layer.
The printing conditions are the same as in the first embodiment. The maximum amount of ink applied was 30 g / m ² .
After printing, firing was performed at 550 ° C. using an electric furnace for ceramics.

Comparative Example 1

Using the ink used in Example 1, a recorded matter was formed on an untreated tile in the same manner as in Example 1.
At that time, bleeding of the image occurred during the printing, and after the printing, baking was performed at 830 ° C. using an electric furnace for ceramics.

The ink-jet printing method of the present invention is an ink-jet printing method capable of providing a product which is free from image bleeding, has excellent light resistance, and is excellent in adhesion and durability when coloring an inorganic base material.

Claims (2)

When inkjet printing an inorganic substrate using an ink having an inorganic pigment and a dispersion medium as an essential component, after providing an ink receiving layer having an unfired glass frit as an essential component, the inkjet printing is performed. An ink-jet printing method on an inorganic substrate, characterized by further firing. The method according to claim 1, wherein the ink receiving layer contains an organic binder.