JPH089258B2 - Marking method - Google Patents

Description

Detailed Description of the Invention

The present invention relates to a marking method for marking the surface of a heat resistant substrate by an ink jet printing method.

[0002]

2. Description of the Related Art In recent years, heat resistant base materials such as ceramics, metals and glass have been widely used, and the base materials are often marked. By the way, as a marking method, a screen printing method, a spray printing method and the like are widely adopted, but there is a problem that it is difficult to mark a precise pattern. Therefore, an ink jet printing method capable of performing a precise pattern marking. Is getting more and more attention.

However, when marking is carried out by the ink jet printing method, the ink droplets ejected from the nozzles of the ink jet printer are minute and therefore the surface of the base material has a liquid absorbing property, or the surface of the base material and the ink have similar colors. In that case, there was a problem that the visibility of the marking film was poor. Furthermore, since the dye that is a constituent of the ink used in the ink jet printing method is usually an organic dye, the "annealing" of the base material, that is, the removal of internal flaws of the base material (molded product) and the crystal structure For the purpose of adjustment, heating is usually performed at a temperature of about 400 ° C. or higher and gradually cooled, but at that time, the organic dye is decomposed, the marking film disappears, or the visibility is deteriorated. There was also.

In order to solve the former problem, it is conceivable to apply a coating film of a different color from the ink on the surface of the substrate in advance. Therefore, there is a problem in that printing cannot be performed unless the coating film is dried, resulting in a complicated process.

[0005]

In view of the above situation, the present inventors have taken advantage of the above-mentioned characteristics of the ink jet printing method and have good visibility of the marking film, and further "anneal" the substrate. The present invention has been achieved as a result of earnest research on a marking method that can obtain a marking film that does not disappear in steps and does not cause bleeding in a small number of steps.

[0006]

That is, the present invention is to apply a heat-resistant coating to the surface of a heat-resistant substrate to form an uncured colored coating film, and then to the surface of the coating film, a solvent-soluble metal-containing dye. And a solvent-soluble heat-resistant binder as a main component, which has a specific gravity and a surface tension smaller than that of the above-mentioned paint, and ejects an ink of a different color from the above-mentioned paint by an ink jet printing method to form a marking film, and then the obtained marking The present invention relates to a marking method for simultaneously curing a film and the coating film.

The present invention will be described in detail below. As the heat-resistant paint used in the present invention, as long as it is a colored paint having heat resistance such that the coating film is not damaged at the "annealing" temperature (usually 400 ° C. or higher) of the heat-resistant substrate, Known paints can be applied without particular limitation, and examples thereof include inorganic paints having an alkali silicate, aluminum phosphate or the like as a binder, and organic paints having a silicone resin or a titanate resin as a binder. . However, the heat-resistant paint used must be different in color from the ink to be described later, because it is applied in order to make the marking film visible. It is needless to say that the "different color" is included not only in the difference in hue but also in the same hue if the visibility is improved due to the difference in brightness and saturation. The ink used in the present invention is an ink containing a solvent-soluble metal-containing dye and a solvent-soluble binder that is heat-resistant and can withstand the temperature of "annealing" as a main component.

The solvent-soluble metal-containing dye is preferably an organometallic chelate dye of a metal having a valency of 2 or more and having a coloring property of cobalt, iron, nickel, manganese, antimony, etc. Specifically, Solvent Black 6 , Solvent Blue
53, Solvent Brown 34, Solvent Yellow 89, Solvent
Violet 1, Solvent Red 9, Solvent Black 2 and the like can be mentioned as typical ones, but any metal-containing dye that is soluble in a solvent and has a coloring property even after “annealing” can be used without particular limitation.

As the above-mentioned binder, any conventionally known binder can be used as long as it is a solvent-soluble binder and has heat resistance that does not decompose or deteriorate at the "annealing" temperature. Specifically, a resin represented by a silicone resin or the like has a phosphorus atom in the molecule, and in the presence of a polymerization initiator,
Oligomer capable of radical polymerization by heating, for example

[0010]

[Chemical 1]

An oligomer represented by the formula [a commercially available product is "phosphazene coat PC" (trade name of Idemitsu Petrochemical Co., Ltd.), etc., and the like. The ink used in the present invention includes the above dyes, binders and solvents for dissolving them, further curing catalysts, polymerization initiators, modified resins, ordinary dyes, conductivity adjusters, surfactants, etc. It is composed of

As the solvent, alcohols such as methanol, ethanol and isopropanol, hydrocarbons such as xylene and toluene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, Typical examples include carbitols such as ethylene glycol monobutyl ether and aliphatic esters such as ethyl acetate and butyl acetate.

The amount of the metal-containing dye compounded in the ink used in the present invention is preferably 2 to 60% by weight in the ink in view of the visibility of color development and the stability of the ink. Further, the compounding amount of the binder is preferably 1 to 40% by weight. Moreover, the compounding amount of the solvent is preferably 10 to 80% by weight. The ink is
Naturally, the properties suitable for ink jet printing are necessary,
Therefore, the viscosity of the ink should be adjusted to 1 to 10 CPS / 20 ° C., the specific resistance to 200 to 3000 Ωcm, the specific gravity to 0.8 to 1.2, and the surface tension to 20 to 60 dyne / cm. More importantly, the specific gravity and surface tension of the ink are higher than those of the heat-resistant paint immediately after applying the heat-resistant paint so that bleeding does not occur immediately when the ink is ink-jet printed in the wet state. You must use the smaller one.

An ink having such a composition and properties is used as an ink for ink jet printing by mixing and stirring each component, filtering and purifying with a pore size 1.0 μ membrane filter. Next, the marking method of the present invention will be described. As the base material applied in the present invention, any material having various heat resistance such as ceramics, metal and glass can be used without particular limitation, and these base materials may be surface-treated or ground-treated if necessary. Good.

A heat resistant paint is applied to the surface of such a substrate by means of spray coating, roll coating, dip coating, flow coater coating, brush coating and the like. The coating amount can be arbitrarily set depending on the purpose of use of the base material, etc., but it is usually suitable that the dry film thickness is 20 to 100 μm. After the colored coating film is applied to the surface of the substrate in this manner, the ink is discharged by the ink jet printing method while the coating film is uncured, preferably within a few seconds to a few minutes to form a marking film. As a printer used in the ink jet printing method, a conventionally known printer can be applied, and specifically, for example, a charge control method, an ink-on-demand method, or a method of ejecting ink by a thermal head is typical. As. After thus forming the marking film on the uncured colored coating film, both coating films are simultaneously cured at room temperature or by baking. Note that these curing steps are not special and may be cured by heating in "annealing".

[0016]

According to the marking method of the present invention, a marking film having excellent visibility is obtained, and even if a marking film is formed on an uncured colored coating film by an ink jet printing method, no blurring occurs. Therefore, it can be said that the marking method has a high practical value because the step of curing the colored coating film can be omitted and the step can be shortened.

[0017]

EXAMPLES The present invention will now be described in more detail with reference to examples. In the examples, "parts" and "%" are shown by weight. Example 1 A silicone resin white paint ["Pyrosin FX518" (trade name, manufactured by Oshima Kogyo Co., Ltd., surface tension 34.5 dynes / cm, specific gravity 1.39) is dried to a thickness of 30 µm on the surface of an aluminum casting substrate. Spray-painted and then immediately filtered with a pore size 1.0μ membrane filter consisting of the following composition and purified yellow ink (surface tension 29.5
Dyne / cm, specific gravity 0.96) was discharged by an ink jet printer and printed. Immediately thereafter, the marked substrate was placed in a furnace heated to 520 ° C. and “annealed”.

Ink composition Silicone resin Note 1) 10 parts Methyl ethyl ketone 50 parts Ethyl alcohol 10 parts CI Solvent Yellow 89 30 parts (cobalt chelate dye) Note 1) “Pelgan D” (trade name of Dow Corning) Viscosity 150 CPS (25 C), nonvolatile content 42% Comparative Example 1 CI Solvent Y was used as a dye for ink in Example 1.
Metal-free dye CI Solvent instead of ellow 89
A silicone resin-based white paint was applied in the same manner except that Black 3 was used, followed by marking by the ink jet printing method, and the substrate was "annealed".

Comparative Example 2 A silicone resin white paint was applied in the same manner as in Example 1 except that the following silicone resin platinum paint (surface tension 28.2 dyne / cm, specific gravity 1.00) was used, followed by ink jet printing. The substrate was "annealed" by marking according to the method. Coating composition Silicone resin Note 1) 10 parts Xylene 55 parts Toluene 5 parts Methyl ethyl ketone 18 parts Oxidation titanium 10 parts Additives 2 parts Example 2 Tension 38.9 dynes / cm, specific gravity 1.46) and black ink (surface tension 28.7c)
m, specific gravity of 0.97) was applied in the same manner except that the substrate was "annealed" by marking with the ink jet printing method.

Coating composition Sodium silicate 45 parts Colloidal silica 5 parts Lead sinter 10 parts Water 40 parts Ink composition Acrylic modified silicone resin Note 2) 15 parts Ethyl alcohol 60 parts Ethyl alcohol 5 parts CI Solvent Black 2 20 parts ( Iron-containing chelate dye) Note 2) “RX-915” (trade name of Nippon Carbide Industries Co., Ltd.) Viscosity 5000 CPS (25 ° C.), non-volatile content 60% Comparative Example 3 In Example 1, the white paint was not applied and the aluminum casting base was directly applied. The substrate was "annealed" in the same manner except that the material surface was marked by the ink jet printing method.

Regarding the "annealed" marking substrates obtained from Examples 1 and 2 and Comparative Examples 1 to 3, the visibility of the marking film (visual judgment), the bleeding property of the printing (visual judgment) and the marking film The results of examining the adhesion (cellophane tape peeling test) are shown in Table 1. ────────────────────── Table 1 Actual Examples Comparison ──────────────────── ─── 1 2 1 2 3 3 ──────────────────────────────── Visuality Good Good Good Good Bad Good Good Bad ──────────────────────────────── Nijimi no no no no yes no ───────── ─────────────────────── Adhesiveness Not peeled off Not peeled off ─ ─ ──────────────── ───────────────── As is clear from Table 1, the marking film obtained by the method of the present invention is visible, has no bleeding, and further adheres. There was also a nature. On the other hand, Comparative Example 1 using an organic dye other than the metal-containing dye as the ink had good visibility before "annealing", but had no visibility after "annealing".

In Comparative Example 2 in which a paint having a surface tension smaller than that of the ink was used, it was found that a marking film was applied, but bleeding occurred and it was of no commercial value. Comparative Example 3 in which the marking film is directly applied to the base material is
The marking film had poor visibility and was of no commercial value.

Continuation of the front page (56) Reference JP-A-63-283981 (JP, A) Actual development 61-168963 (JP, U) JP-B 48-18333 (JP, B1) JP-B 55-34712 (JP , B2) JP-B-56-46441 (JP, B2)

Claims (1)

[Claims] 1. A heat-resistant paint is applied on the surface of a heat-resistant substrate to form an uncured colored coating film, and then a solvent-soluble metal-containing dye and a solvent-soluble heat-resistant binder are mainly formed on the surface of the coating film. As a component, an ink having a specific gravity and a surface tension smaller than that of the coating material and having a color different from that of the coating material is discharged by an ink jet printing method to form a marking film, and then the obtained marking film and the coating film are simultaneously cured. Marking method characterized by.