JP4368640B2 - Inkjet printing method on inorganic substrate - Google Patents

Description

  The present invention relates to an image forming method using an ink jet method, and more particularly to a method of ink jet printing on an inorganic substrate such as ceramic.

2. Description of the Related Art Conventionally, a recording method using ink jet printing technology has been widespread.
In recent years, media used as recording media are not limited to paper, and image recording has been performed on various materials such as films, plastics, ceramics, metals, and fabrics.

As a coloring material for ink jet printing, a dye is used for various purposes, but the dye cannot sufficiently satisfy light resistance.
In order to satisfy light resistance, an organic pigment having excellent light resistance may be selected and used as a coloring material. In that case, the light resistance is remarkably improved as compared with the dye, but it is not sufficient as a coloring material for inorganic base materials such as ceramics having durability and light resistance.

As a method for solving the above problems, there has been proposed a method of forming an image on the recording surface of a recording medium using an inorganic pigment having excellent light resistance as a coloring material and further using ink containing glass frit as a binder thereof. ing.
In this method, after printing an image on a recording medium, the ink and the recording medium are fused by firing.
Using such a technique, decoration on an inorganic base material such as ceramics, enamel, glass or metal is carried out by screen printing, brush writing (hereinafter, handwritten) or the like.

  However, the number of colors and reproducibility are limited for screens and handwriting, and the current situation is that one-point products such as personal orders cannot be used for screens.

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

In the past painting on an inorganic base material by silk screen or handwriting, a large amount of upper paint is blended with a high-viscosity solvent and kneaded in a mortar to prepare a high-viscosity dispersion, followed by painting.
Therefore, the dispersion liquid does not generate a bleeding phenomenon due to its low fluidity on the inorganic base material, and when the volatile components in the dispersion liquid volatilize, the dispersion liquids of other colors are superimposed. Is also possible.

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

As a method of solving such bleeding phenomenon,
Has proposed an inorganic pigment ink jet printing method using a hot-melt material. In this method, since the heat-meltable substance is solidified after the discharge and landing, the image after printing does not cause bleeding, but since the heat is applied to the base material at the firing stage, the heat-meltable ink is remelted and the image is reheated. There is a concern that it will bleed.

In addition, as a method to eliminate nozzle clogging,
Has proposed an ink in which a volatile material is added to a water-based 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 ejection stability is lacking. JP 2001-39008 A JP 2001-81363 A

  The present invention provides an image forming method using an ink jet system, which is free from bleeding of the formed image and can form an image having good adhesiveness on the base material. To do.

Thus, as a result of intensive research on the background of such problems, the present inventor has used an inorganic pigment inkjet ink having an inorganic pigment , a glass frit powder, and a dispersion medium as essential components, and has an unfired glass frit. By performing inkjet recording using the ink on an inorganic base material provided with a receiving layer, there is no occurrence of bleeding after printing and after firing, and a strong fired film is obtained. It has been found that a remarkable effect of excellent adhesion can be obtained.

Therefore, the present invention provides an inorganic substrate with an ink receiving layer containing unsintered glass frit as an essential component, and then performs ink jet printing using an ink containing an inorganic pigment, glass frit powder and a dispersion medium as essential components. An ink-jet printing method on an inorganic base material characterized by firing.

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, tiles and metals. If it is a base material which consists of inorganic materials, it will not specifically limit.
In the present invention, such an inorganic base material 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 an arbitrary size can be used. However, the particle size preferably falls within the range of 1 to 30 microns from the viewpoint of liquid absorption and coating properties. used. The thickness of the ink receiving layer is not particularly limited, but is usually preferably about 1 to 1000 microns, and is usually adjusted according to the type of ink or inorganic substrate.

  Glass frit components used in the ink-receiving layer include lithium carbonate, sodium carbonate, potassium carbonate, lead oxide, bismuth oxide, etc. for alkali metal compounds, and barium carbonate, strontium carbonate, calcium carbonate, magnesium carbonate for alkaline earth metals. Zinc oxide, etc., neutral components such as aluminum oxide and aluminum hydroxide, acidic components include silicon oxide, boric acid, zirconium oxide, titanium oxide, and other natural products such as feldspar, silica, borax, kaolin These materials can be used as frit by dissolving these materials alone or in combination.

  In addition to the unfired glass frit, the ink receiving layer of the present invention includes a dispersant, a heat stabilizer, an antioxidant, an anti-reducing agent, an antiseptic, a pH adjuster, an antifoaming agent, a wetting agent, as necessary. Additives such as adhesives and penetrants and water can be added to increase fluidity.

  The glass frit is particularly preferably deposited on an inorganic substrate using an organic binder to form an ink receiving layer. By using a small amount of organic binder to form an ink-receiving layer with glass frit attached to each other, the synergistic effect of subsequent inkjet printing and baking prevents the formed image from bleeding and has excellent adhesion to the substrate. A quality image can be formed.

  As the organic binder, water-soluble or water-dispersible organic polymers are preferable, and those having no metal atom in the molecular structure are particularly preferable. This is because metal atoms may be oxidized during firing to impair the transparency of the ink receiving layer.

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, processed natural Semi-synthetic polymers such as gum, polyvinyl alcohol, polyethylene glycol, polyvinyl acetate, polyvinyl butyrate resin, polyvinyl acrylate resin, polyvinyl methyl resin, cross-linked polyacrylic acid, polyacrylic acid soda, polyacrylic acid ester, 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 with respect to 100 parts by weight of the glass frit.

Any method can be adopted as a method for forming the unfired glass frit ink receiving layer, and specific examples include a coating method, a laminate method, a spray method, an ink jet method, and the like, but there is a method capable of forming a uniform continuous layer. preferable.
When the glass frit and organic binder are used as an aqueous dispersion, the water-soluble concentration is 50 to 80%, and the viscosity is adjusted to 100 to 20,000 cps. This is preferable because the coating property when a 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 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 image after printing, and when the applied amount of the ink receiving layer is more than 10 times the maximum applied amount of ink There is a tendency that cracks are likely to occur in the fired glass film.
Here, the applied amount of the ink receiving layer refers to a weight (dry solid content) in a dry state in which water is evaporated by 100%. In addition, the maximum amount of ink applied is the amount of ink applied in a portion where the amount of ink applied per unit area is the largest because the amount of ink applied per unit area varies depending on the image to be printed. It is the liquid weight of the ink.

As the ink composition used in the present invention, an ink composition containing glass frit as an essential component together with an inorganic pigment and a dispersion medium is used.

  Examples of inorganic pigment components used in the present invention include titanium oxide, zinc sulfide, black iron oxide, black copper oxide, black chromium oxide, yellow iron oxide, yellow nickel titanium, cadmium sulfide, selenium, and selenization. Cadmium, lead chromate, lead molybdate, red iron oxide, cobalt oxide, hydrous 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, mercury cadmium sulfide, bitumen, ultramarine, and the like, but are not limited thereto and can be used. These can be used as a single product, a mixture, a double salt, or a complex salt.

In the preferred embodiment of the present invention, the glass frit used in the ink is an alkali metal compound such as lithium carbonate, sodium carbonate, potassium carbonate, lead oxide, bismuth oxide, etc., in the same manner as the glass frit component used in the ink receiving layer. Barium carbonate, strontium carbonate, calcium carbonate, magnesium carbonate, zinc oxide, etc. for alkaline earth metals, aluminum oxide, aluminum hydroxide for neutral components, silicon oxide, boric acid, zirconium oxide, titanium oxide, etc. for acidic components Further, natural materials such as feldspar, quartzite, borax, kaolin and the like, which are mixed systems, can be used, but these materials can be dissolved alone or in combination to be used as a frit.
Of course, it is also possible to use an overpaint made from an inorganic pigment and glass frit.

The medium for dispersing the inorganic pigment and the glass frit in the ink composition used in the present invention includes water, an organic solvent, a wax, or a mixture thereof, but is not limited to these.
Furthermore, when dispersing an inorganic pigment and glass frit or an upper paint in the above-mentioned dispersion medium in the ink, various dispersants / surfactants can be arbitrarily used alone or in a mixed form.
Examples of such anionic surfactants include fatty acid soaps, alkyl succinates, alkylbenzene sulfonic acid sodium salts, alkyl naphthalene sulfonic acid sodium salts, alkyl sulfate ester sodium salts, polyoxyethylene alkyl ether sulfate sodium salts, dialkyl sulfone salts. Succinate sodium salt, sodium alkyl phosphate, polycarboxylic acid type polymer surfactant, alkyltrimethylammonium chloride as cationic surfactant, alkyldimethylbenzylammonium chloride, polyoxyethylene alkyl ether as nonionic surfactant, poly Examples of the oxyethylene alkyl allyl ether, sorbitan fatty acid ester, and amphoteric surfactant include alkyl betaines and amide betaines. Here, as the anionic surfactant, not only a sodium salt but also any metal salt or ammonium salt can be used.
In addition to the above-mentioned dispersants, waxes can also be used as dispersants for solid inks such as hot melt inks.
Further, any material other than these that exhibits a dispersion effect can be used.
Moreover, it is naturally possible to add additives such as a heat stabilizer, an antioxidant, a reduction inhibitor, an antiseptic, a pH adjuster, an antifoaming agent, a wetting agent, and a penetrating agent as necessary.

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

The inkjet printing apparatus used for 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 substrate according to the present invention, an image having no bleeding phenomenon after printing and after firing can be formed.
One reason for this is that unfired glass frit consists of particles, so that in the layer where they are deposited, a receiving layer with voids between the particles is formed, so even if liquid ink is ejected and landed. The liquid component is efficiently absorbed in the receiving layer.
Further, by using glass frit as the receiving layer, it is possible to form a glass film having excellent adhesiveness by melting and mixing the glass frit in the ink and the glass frit in the receiving layer in a preferred embodiment.

In the preferred embodiment, the glass frit used in the ink and the glass frit used in the ink receiving layer are selected from materials having appropriate thermal expansion coefficient and softening point depending on the base material to be colored. It can be fired at a temperature of
For example, when 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 of about 600 ° C. or lower. In this case, the firing temperature is preferably set to about 600 ± 100 ° C.
On the other hand, if the thermal expansion coefficients of the base material and each frit are remarkably different, it should be noted that cracks are generated in the glass melt layer after firing or no adhesion occurs at all.

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

  Next, although an Example is given and this invention is demonstrated, this invention is not necessarily limited to the Example.

A glass frit 12-3699 (softening temperature: 779 ° C., manufactured by Nippon Fellow) was used as the ink receiving layer, and a ball mill was used for dry dispersion to an average particle size of about 10 microns. To 100 parts by weight of the glass frit powder, 10 parts by weight of hydroxypropyl cellulose (organic binder: KLUCEL M, 10% aq product, 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 an ink, inorganic pigment and glass frit SUNSHINE AZURE (cobalt oxide-based metal oxide + frit: Seldeck)
20 parts by weight Dispersant Carribbon B (polycarboxylic acid type activator: Sanyo Kasei) 1 part by weight Wetting agent Polyethylene glycol 400 (Nippon Yushi) 10 parts by weight Pure water 69 parts by weight After mixing with a ball mill, filtration The impurities were removed to produce a homogeneous blue ink.
A recorded matter was obtained by using an ink jet printer as a method of applying the prepared ink to a tile provided with an ink receiving layer.
The printing conditions are as follows. The maximum amount of ink applied was 10 g / m ² .
After printing, firing was performed at 830 ° C. using an electric furnace for ceramics.
The image after printing and after baking had no bleeding, and an image of a glass film 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) Drive frequency: 1 (kHz)
E) Resolution: 180 (dpi)

〔Evaluation test〕
A) Bleeding: Visual ・ Sharp images are maintained without bleeding after printing and firing. (○)
・ Some blurring occurs after printing and firing. (△)
・ Images are not preserved at all after printing and burning, and (×)
I) Scratch resistance: JIS K5400 (8.4.2 Hand-scratch method)
2H hardness or higher and no damage ... ◎
No damage with H hardness ...
No damage due to HB hardness ・ ・ ・ ・ ・ ・ △
Damaged below HB hardness ・ ・ ・ ×
C) Peel resistance: A cellophane tape is applied to the cured film, the tape is peeled off, and the subsequent state is confirmed.
The cured film does not peel from the substrate ...
Cracks in the cured film and bubbles enter between the substrate and the cured film ...
The cured film is completely peeled off ...

A glass frit 12-3619 (softening temperature: 571 ° C., manufactured by Nihon Fellow) was used as the ink receiving layer, and dry dispersion was carried out to a mean particle size of about 10 microns using a ball mill. To 100 parts by weight of the glass frit powder, 10 parts by weight of polyethylene glycol 2000 (organic binder: PEG # 2000, manufactured by NOF Corporation) and 30 parts by weight of pure water are added, kneaded in a mortar, and glass (plate glass) using a screen. After coating, the film was dried 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 metal oxide: Titanium industry)
5 parts by weight Frit 12-3619 15 parts by weight Dispersant Carribon B (polycarboxylic acid type activator: Sanyo Kasei) 1 part by weight Wetting agent Polyethylene glycol 400 (Nippon Yushi) 10 parts by weight Pure water 69 parts by weight After dispersion using, filtration was performed to remove impurities, and a homogeneous red ink was prepared.
A recorded matter was obtained by using an ink jet printer as a method for applying the prepared ink to the glass provided with the ink receiving layer.
The printing conditions are the same as those in the first embodiment. The maximum amount of ink applied was 5 g / m ² .
After printing, firing was performed at 600 ° C. using an electric furnace for ceramics.

A glass frit 01-4303 (softening temperature: 459 ° C., manufactured by Nippon Fellow) was used as the ink receiving layer, and dry dispersion was performed to an average particle size of about 10 microns using a ball mill. To 100 parts by weight of the glass frit powder, 2 parts by weight of carboxymethyl cellulose (organic binder: Serogen PR, 10% aq product, Daiichi Kogyo Seiyaku Co., Ltd.) and 30 parts by weight of pure water are added and kneaded in a mortar. The aluminum plate used was coated and then dried at 110 ° C. for 10 minutes. 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 .
Ink Inorganic pigment 42-701A (Cobalt oxide-based metal oxide: Nippon Fellow) 5 parts by weight Dispersant Carribon B (polycarboxylic acid type activator: Sanyo Kasei) 1 part by weight Wetting agent Polyethylene glycol 400 (Nippon Yushi) 10 parts by weight Part 84 parts by weight of pure water was blended, dispersed using a ball mill, filtered to remove impurities, and a homogeneous black ink was prepared.
A recorded matter was obtained 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 those 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, recorded matter was created 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, firing was performed at 830 ° C. using an electric furnace for ceramics, but bleeding was also confirmed in the image after baking.

The ink-jet printing method of the present invention is an ink-jet printing method that can provide a product having no blur of image, excellent light resistance, and excellent adhesion and durability when colored on an inorganic substrate.

Claims (2)

An ink receiving layer containing an unfired glass frit as an essential component is provided on an inorganic substrate, and then inkjet printing is performed using the ink containing an inorganic pigment, a glass frit powder, and a dispersion medium as essential components, followed by firing. An inkjet printing method for an inorganic substrate. The method according to claim 1 , wherein the ink contains polyethylene glycol and the ink receiving layer contains an organic binder.