JPH0227147B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a decorative metal plate using electron beam irradiation.

Conventionally, the industrial methods for manufacturing decorative metal plates that form various patterns on metal plates include baking the primer layer and top coating layer at high temperatures, and the pattern forming method includes gravure off. There are a set method, a transfer method, and a decorative film lamination method in which decorative film is baked at a high temperature using a heat-curing adhesive.

However, with the gravure offset method, fogging occurs (a phenomenon in which the edges of the printed pattern become unclear due to the ink transferred from the plate shifting from the same position on the rubber plate and due to poor cleaning of the rubber plate). There are few problems with wood grains that allow for this, but it cannot be applied to abstract patterns or patterns that require clear edges. The transfer method has problems such as high price and poor productivity due to limitations on transfer speed. In the decorative film lamination method, there are problems such as energy saving, resource saving, and volatilization of solvent into the atmosphere because it uses heat curing.

For this reason, there is an increasing demand for solvent-free, energy-saving, high-speed processing, etc., and methods of using primers or overcoating paints that are crosslinked and cured by electron beam irradiation are being studied.

The present invention was completed as a result of intensive research in view of the above-mentioned current situation, and its main points are, firstly, the application of electron beam irradiation, and secondly, the application of electron beam irradiation, and secondly, the application of electron beam irradiation. The purpose is to apply a decorative material layer.

That is, in the present invention, on a treated or untreated metal plate, a decorative material layer impregnated with an electron beam crosslinkable compound and having a desired printed pattern, an electron beam crosslinkable transparent paint layer, and, if necessary, a transparent resin film layer are formed. The present invention relates to a method for producing a decorative metal sheet, which comprises applying an electron beam to the paint layer or film layer to cure the compound and paint.

The advantages of the above manufacturing method are: (1) Since printing is not limited to the gravure offset method, precise printing such as gravure printing and offset printing can be easily performed even in multicolor printing, and beautiful pattern printing is possible. , (2) Since the cosmetic agent is impregnated with an electron beam crosslinkable compound, it is cured together with the paint layer by electron beam irradiation, resulting in a decorative metal plate with good resistance to various types of electron beams. By applying radiation irradiation, it becomes possible to use no solvent, which is advantageous in terms of working environment, high-speed processing, and energy saving.

The present invention will be explained in more detail below.

The metal plates used in the present invention include steel plates, aluminum plates, copper plates, alloy plates, metal plates whose surfaces have been subjected to plating treatment, chemical conversion treatment, etc., or electron beam crosslinking compounds or paints. A metal plate treated with a primer is used to improve adhesion to the metal plate and to prevent rust, and may be in the form of a cut plate or wound (coil).

Another embodiment of the present invention is that when an electron beam cross-linked primer is used as the primer in an uncured state, the adhesion is improved, and the primer is simultaneously cured by electron beam irradiation in the final step. It is industrially most preferable because it allows

The base material for the decorative material used in the present invention may be any material that is sufficiently impregnated with the electron beam curable compound and that is easy to print on, but thin paper or titanium paper is usually used. It is preferable to use

As an electron beam crosslinkable compound, a curable prepolymer and/or monomer having unsaturated bonds are essential components, and other additives such as resins, pigments, preservatives, etc. that do not have unsaturated group bonds are added as necessary. It is made by blending.

Curable prepolymers include epoxy resin (meth)acrylate, alkyd resin (meth)
Acrylate type, OH-containing petroleum resin (meth)acrylate type, unsaturated polyester type, urethane type in which OH-containing resin and OH-containing (meth)acrylate are bonded through a diisocyanate compound, etc. can be used.

Monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol(meth)acrylate Acrylate, alkyl (meth)acrylate (alkyl group having 1 to 18 carbon atoms),
Usable examples include monohydric phenol or polyhydric phenol with alkylene oxide added to the hydroxyl group and esterified with acrylic acid or methacrylic acid, styrene, allyl alcohol ester, glycidyl (meth)acrylate, and the like.

There are methods known per se to impregnate decorative materials with the electron beam crosslinkable compound, such as dipping, roll coating, and spraying methods, but electron beam crosslinkable transparent paints applied on decorative materials also have almost the same composition. Therefore, a decorative material with a desired printed pattern that is not impregnated with an electron beam crosslinkable compound is placed on a metal plate, and then an electron beam crosslinkable transparent paint is applied. It is industrially advantageous to carry out the step of impregnating the decorative material with the electron beam crosslinkable compound by allowing it to stand for a sufficient time to partially impregnate the decorative material, at the same time as the step of applying the electron beam crosslinkable transparent paint. This is a great method.

In the present invention, as the method of printing on the decorative material, it is preferable to use sophisticated and high printing speed methods such as gravure printing and offset printing, but screen printing,
Any method such as gravure offset printing can also be used. Any printing ink can be used, such as a thermosetting type, a radiation curing type, a solvent volatilization type, and a permeation drying type. However, printing inks whose printed patterns are dissolved in electron beam crosslinkable compounds or monomers in transparent coatings must of course be avoided.

The electron beam crosslinkable transparent coating used in the present invention is mainly composed of the curable prepolymer and/or monomer used in the electron beam crosslinkable compound described above, and depending on the purpose, resins without unsaturated bonds can be used. Additives such as pigments, matting agents, etc. can be added to the extent that they do not impede transparency. This paint is applied onto the decorative material layer by a method known per se, such as a roll coating method,
As mentioned above, if a decorative material is not impregnated with an electron beam crosslinkable compound or is impregnated with an insufficient amount of the electron beam crosslinkable compound, the paint will be able to become Functions as all or part of a linearly crosslinked compound.

In the present invention, after applying the electron beam crosslinkable transparent paint, a transparent resin film layer may be further applied thereon if necessary. This resin film has the effect of suppressing polymerization inhibition caused by the presence of oxygen when a paint or the like is cured by electron beam irradiation.
This film may be peeled off after the paint has hardened, or it may be left in close contact with the film. It is preferable that the film is treated with an appropriate release agent when it is to be peeled off, and that it is treated with an appropriate release agent when it is to be kept in close contact. As this transparent resin film, films of polyester, polyolefin, polyvinyl chloride, polycarbonate, polyamide, etc. are used.

In the present invention, a known electron beam irradiation device can be used to irradiate the electron beam,
For industrial purposes, it is best to use a capacitor with a capacity of 100 kilovolts to several megavolts. In addition to using a transparent resin film as described above, in order to avoid polymerization inhibition due to oxygen, it is also possible to irradiate electron beams in an atmosphere in which the air is replaced with an inert gas such as nitrogen gas or carbon dioxide gas. preferable.

The present invention will be explained in more detail below using Examples. The part in the example indicates the polymerized part.

Example 1 On a galvanized steel sheet, 50 parts of a urethane prepolymer prepared by reacting 2-hydroxyacrylate with a polyester polyol via a diisocyanate, 50 parts of 1,6-hexanediol diacrylate, 3 parts of zinc yellow, and rutile were placed on a galvanized steel sheet. Three parts of the mold titanium white were sufficiently kneaded using a ball mill, and a rust-preventing white primer was uniformly applied using a gravure offset printing machine to a film thickness of 5 μm.

On the other hand, an abstract pattern was printed in multiple colors on thin paper using an offset printing machine using FD ink (ultraviolet curable printing ink, product name manufactured by Toyo Ink Manufacturing Co., Ltd.), and the ink was cured by irradiation with ultraviolet rays. The obtained decorative material having a printed pattern is dipped in a mixture of 60 parts of the above urethane prepolymer and 40 parts of 1,6-hexanediol diacrylate to impregnate it, and then passed between two rolls. Excess impregnating liquid was removed.

The impregnated decorative paper was placed on the steel plate coated with the above primer, and a transparent paint with the following formulation was applied with a roll coater to a thickness of 15μ, and irradiated with an electron beam in a nitrogen gas atmosphere. A decorative steel sheet with excellent durability was obtained by crosslinking and curing the coating, impregnation layer, and primer layer.

Transparent paint formulation 65 parts of the above urethane prepolymer 1,6-hexanediol diacrylate
40 copies Example 2 The same operations as in Example 2 were repeated except that a paint containing 100 parts of transparent paint and 3 parts of a matting agent was used to obtain a decorative metal plate with a matte surface. Ta.

Claims (1)

[Scope of Claims] 1. An electron beam crosslinkable primer is applied on a metal plate, and the uncured primer is impregnated with an electron beam crosslinkable compound to form a cosmetic layer having a desired printed pattern, and an electron beam crosslinkable primer. 1. A method for producing a decorative metal sheet, which comprises applying a transparent paint layer and curing the primer and compound by irradiating electron beams from the side of the paint layer. 2. A transparent resin film layer is applied on the electron beam crosslinkable transparent paint layer, and the transparent resin film is peeled off after the primer and compound are cured by irradiating the electron beam from the side of the film layer. A method for manufacturing a decorative metal plate according to claim 1.