JPS6035194B2 - Coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a coating method for improving the adhesion between a substrate and an ultraviolet curable composition when coating or printing an ultraviolet curable composition such as an ultraviolet curable paint or printing ink onto a substrate. Regarding.

Conventionally, when applying or printing an ultraviolet curable composition onto a substrate such as a metal plate, the adhesion of the ultraviolet curable composition to an untreated substrate is extremely poor. It was being processed.

However, the resins that can be used for size coaching and white coating are limited, and in particular, those treated with coating agents using acrylic resins or vinyl resins only show low adhesion to the level of coating or printing on untreated metal plates. . In addition, size coaching and white coating treatments require a long time or a large heat dryer, such as 18030 heat drying for 10 minutes, resulting in high running costs. In order to save labor, there is a need to establish a coating method that does not cause problems in adhesion even when size coating and white coating are omitted. The present inventors uniformly coated a metal alcoholate or its chelate compound diluted with a low boiling point solvent such as methanol to form a thin film, and after scattering the solvent, applied an ultraviolet curable composition on top of the thin film. It was discovered that when an object is coated or printed and cured by irradiation with ultraviolet rays, a remarkable improvement in adhesion can be obtained, and the cost is also significantly lower than before.
The present invention was achieved by establishing a coating method that saves labor in the process.

That is, the present invention provides a substrate with a thin film layer of one or more metal organic compounds selected from metal alcoholates or their chelate compounds, then coats or prints an ultraviolet curable composition, and irradiates the substrate with an ultraviolet curable composition. The present invention also relates to a coating method characterized by curing the composition.

The substrate in the present invention is a bare tin plate, TFS (T
In-Free-Steel) plates, untreated metal plates such as aluminum plates, treated metal plates treated with size coaching, white coating, etc. using acrylic or vinyl resins, plastic plates, and glass. Various materials such as plates can be used.

Next, as the metal alcoholate or its chelate compound in the present invention, the metal is preferably aluminum, zirconium, cobalt, titanium, etc. Other metals are also effective, but there are problems in use from the viewpoint of cost and toxicity. .

Alcoholates include ethylate, propylate, butyrate, etc. Metal alcoholates that are industrially easily available are aluminum isopropylate and titanium isof.
Examples include lopilate, zirconium ester, and sialbutyrate. In addition, as the chelate compound, these metal alcoholates are reacted with commonly known chelating agents such as acetylacetone, 3-ethylacetylacetone, 3-phenylacetylacetone, 3-methoxyacetylacetone, dibenzoylacetone, and methoxycarbonium acetone. It is obtained by doing. The method of applying these metal alcoholates or their chelate compounds to a substrate is to make a dilute solution of the metal alcoholate or its chelate compound using a low boiling point solvent such as methanol, acetone, or ethyl acetate, and to apply a general method such as a spray method or a roll coaster method. A uniform coating of the metal alcoholate and its chelate compound can be obtained by applying it by a typical coating method and drying it at room temperature or by heating. A desired coating amount is selected by changing the concentration of the metal alcoholate or its chelate compound in a low boiling point solvent, and is preferably on the order of 9/100 of 1 to 10. This coating method requires only a very short drying time of 1 to 5 seconds, so it is very advantageous in terms of process compared to the drying method used in conventional size coating processes. This system can be incorporated into. That is, it is possible to attach it to the current feeder, coating machine, or conveying unit to the printing machine. The ultraviolet curable composition used in the present invention is one that has been conventionally used, and contains a prepolymer and/or monomer having a radically crosslinkable ethylenically unsaturated double bond and a photosensitizer as essential components, and can be used for other purposes. Colorants, stabilizers, waxes, etc. can be added.

Examples of prepolymers include epoxy resins esterified with acrylic acid or methacrylic acid, alkyd resins having hydroxyl groups esterified with acrylic acid or methacrylic acid, and polyol ester compounds of alkyd or polyester and acrylic acid. Examples of monomers include acrylic acid or methacrylic acid esters of polyhydric alcohols such as ethylene glycol, polyethylene glycol, trimethylolpropane, and bentaerythritol. Generally known photosensitizers can be used, such as penzoin-based ones such as penzoin, benzoin, ethyl ether, and benzoin normal butyl ether, and ketone-based ones such as benzophenone and P-chlorobenzophenone. It is. Next, reference examples, examples, and comparative examples are shown.

Example "Central part" refers to parts by weight. Reference Example 1 71.7 parts of Epikot 828 (bisphenol type epoxy resin manufactured by Shell Chemical Co., Ltd.), 28.3 parts of acrylic acid, 0.1 part of hydroquinone, 0.3 part of triethylenediamine, and a reflux tube and a stirrer. The mixture is charged into a neck flask and reacted for 15 to 20 hours at a temperature of 900 to 12,000 while blowing air, and then pumped out with an acid value of 1 or less.

This was used as Prepolymer A. Using this Prepolymer A, an ultraviolet curable composition was prepared according to the following formulation. Carmine Kyokuhi (red pigment manufactured by Toyo Ink Manufacturing Co., Ltd.) 17.0 parts Prepolymer A 60. Ikarigun 4,4'-bisdiethylaminobenzophenone
1. Ikari-gun Penzophenon 10
．． Ikaribe Pentaerythritol Triacrylate
12. Foundation part 100 - Part ○ Example 1 3 of tetraline propyl titanate on a bare tin plate
3/9 of the weight% methanol diluted solution using a roll coater.
After coating with a coating amount of 100 lumps and drying at room temperature, the ultraviolet curable composition of Reference Example 1 was rated at 9/10 of 30 using an RI tester.
Print on the above-treated metal plate with a coating amount of 0c bridge, and immediately after that, apply 20cm at about 10cm below the Fox W high pressure mercury lamp.
Pass-curing was carried out at a speed of m/min.

Example 2 A 1% by weight acetone diluted solution of ethyl acetoacetate aluminum diisopropylate was applied on a TFS plate using a roll coater at a coating amount of 9/100 of 10, and after drying at room temperature, it was exposed to the ultraviolet rays of Reference Example 1 using an RI tester. The curable composition was printed on the above-treated metal plate at a coating weight of 30:9/100, and immediately after that, it was heated under a 2KW high-pressure mercury lamp for about 1 hour.
Pass-curing was carried out on the 0c twin at a rate of 20/min.

Example 3 Tetrainbutylzirconium 1 on an aluminum plate
．． Apply a 5% by weight diluted ethyl acetate solution with a roll coater at a coating amount of 5 pieces/100cm, dry at room temperature, and then apply RI.
Using a tester, test the ultraviolet curable composition of Reference Example 1 at 9/30.
The above-treated metal plate was printed with a coating weight of 100 centimeters and immediately cured by passing about 10 skins under a 2KW high-pressure mercury lamp at a rate of 20 skins/min.

Example 4 Aluminum sofa on a bare tin plate.

A 0.5 wt% methanol diluted solution of ropyrate was applied at a coating amount of 9/100 of 1 with a roll coater, and after drying at room temperature, the ultraviolet curable composition of Reference Example 1 was coated with a RI tester at a coating amount of 9/100 of 30. Printing was carried out on the above-treated metal plate with a coating weight of the base, and immediately thereafter it was cured by passing it through a 2KW high-pressure mercury lamp about 10 skins below at a speed of 20 m/min.
Example 5 A 1% by weight methanol diluted solution of tetraline propyl titanate was applied using a roll coater onto a tin plate that had been sized with a vinyl resin (9/100 cm of 10) and baked at 18,000 for 10 minutes. 9/100 of 10
After drying at room temperature, the ultraviolet curable composition of Reference Example 1 was printed on the above-treated metal plate using an RI tester at a coating amount of 30 Sakaki no 100, and immediately after that, 2KW high pressure was applied. Pass curing was carried out at a speed of 20 m/min at about 10 cm below the mercury lamp.

Example 6 A 3% methanol diluted solution of tetranepropyl titanate was coated on a glass plate with a roll coater.
/100c Hiiragi coating amount, dried at room temperature, and applied the ultraviolet curable composition of Reference Example 1 with a coating roll at 30 female/10.
Coat the above glass plate with a coating amount of 0, and immediately after that apply
Curing was carried out under a high-pressure mercury lamp at a speed of 20 m/min about 10 skins.

Example 7 Tetraine butyl zirconium 1 was applied to a polyethylene plate.
．． A 5% by weight diluted ethyl acetate solution was applied with a roll coater at a coating amount of 5 mm/100 cm, and after drying at room temperature, the ultraviolet curable composition of Reference Example 1 was coated with a coating roll at a coating amount of 30 mm/10 cm.
It was coated on the above polyethylene plate at a coating weight of 0 c cedar, and immediately thereafter cured by passing about 10 skins under a 2 KW high pressure mercury lamp at a speed of 20 min.

Comparative Example 1 The ultraviolet curable composition of Reference Example 1 was printed on a naked tin plate using an RI tester at a coating amount of 9/100 of 30, and immediately after that, about 10 skin areas were printed under a 2KW high-pressure mercury lamp for 20 minutes.
Pass-curing was carried out at a speed of m/min.

Comparative example 2 Vinyl resin size 1 is placed on a bare tin plate
Immediately after printing the ultraviolet curable composition of Reference Example 1 using an RI tester on a board that had been coated at a coating weight of 9/100c cedar and baked at 1800° for 10 minutes. Curing was carried out approximately 10 cm below a 2 MW high-pressure mercury lamp at a speed of 20 m/min.

Comparative Example 3 Instead of applying the vinyl resin size in Example 2, an acrylic resin white coating agent was applied, and printing was performed and cured in the same manner as in Comparative Example 2 except for the coating.

The curing and drying properties of the ultraviolet curable compositions on the substrates of Examples 1 to 7 and Comparative Examples 1 to 3 were all good, and no difference was observed.

Further, the adhesion of the ultraviolet curable composition was tested using a cellophane tape peeling cross-cut method. The results of this adhesion test are shown in Table 1. Table I

Claims (1)

[Scope of Claims] 1. After applying a thin film layer of one or more metal organic compounds selected from metal alcoholates or their chelate compounds to a substrate, an ultraviolet curable composition is coated or printed, and ultraviolet rays are applied. A coating method characterized in that the composition is cured by irradiation. 2. The coating method according to claim 1, wherein the substrate is an untreated metal plate. 3. Claim 1, wherein the metal alcoholate or chelate compound thereof is a metal alcoholate or a chelate compound thereof of one or more metals selected from aluminum, zirconium, cobalt, and titanium.
The coating method according to items 1 to 2.