JPH03234531A - Manufacture of coated plate - Google Patents

Abstract

PURPOSE:To manufacture a coated plate where peelability of a transparent plastic film is favorable and curing properties of a coating is favorable, by a method wherein an ultraviolet curing type coating composition containing transparent glass powder where a difference between a refractive index of an ultraviolet polymerizable vehicle ingredient and that of a curing clear coating of a vehicle ingredient is specified is applied to the surface of a board. CONSTITUTION:An ultraviolet-curing-type coating composition containing transparent glass powder where a difference between a refractive index of an ultraviolet polymerizable ingredient and that of a curing clear coating of a vehicle ingredient is within 0.3 is applied to the surface of a base. Then after the coated surface is covered by a transparent plastic film, a cured coating is formed by applying ultraviolet rays to the transparent plastic film. The ultraviolet curing type coating composition to be used is constituted essentially of an ultraviolet polymerizable vehicle, optical reaction initiator and the transparent glass powder and the same is obtained by compounding the same with a coloring pigment or an extender pigment or an organic solvent or an additive agent at need. With this construction a coated plate where curing properties of the coating is favorable and peelability of the transparent plastic film is favorable can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a coated plate capable of forming any coating such as a mirror finish, a matte finish, or a textured finish.

<Prior art and problems to be solved> In recent years, ultraviolet curable coating compositions with short curing times of several seconds to several tens of seconds have been applied to metal plates, plastic plates, inorganic plates, wooden plates, etc.
Coated plates with good production efficiency are widely manufactured.

By the way, in order to prevent curing failure due to the influence of oxygen after applying an ultraviolet curable coating composition and before irradiation with ultraviolet rays, a method has been known in which a transparent plastic film is covered immediately after application and irradiated with ultraviolet rays. ing.

However, the method of covering a transparent plastic film is to irradiate it with ultraviolet rays to form a hardened film and then remove the film, but it adheres to the film, making it difficult to remove and damaging the film. There are problems that often occur.

Furthermore, although a transparent film is used, it absorbs some of the ultraviolet rays, so if the T coating is thick, several hundred micrometers long, the lower layers will not be cured sufficiently if the UV irradiation time is short, and even if the N coating is used, it will become discolored. In the case of a film, there were problems such as that it rarely hardened.

In view of the current situation, the present inventors conducted intensive studies to solve the above problems, and as a result, they discovered a method for manufacturing a coated plate with good releasability of the transparent plastic film and good hardening of the coating, and have arrived at the present invention. This is what happened.

<Means for Solving the Problems> That is, the present invention provides an ultraviolet polymerizable vehicle component and
The difference in refractive index between the vehicle component and the cured clear coating is 0.
．． The method is characterized by applying an ultraviolet curable coating composition containing a transparent glass powder having a particle size of 3 or less to the surface of a substrate, then covering the coated surface with a transparent plastic film, and then irradiating it with ultraviolet rays to form a cured film. The present invention relates to a method for manufacturing a coated plate.

The present invention will be explained in detail below.

The ultraviolet curable coating composition used in the present invention is
It contains an ultraviolet polymerizable photoreaction initiator and transparent glass powder as essential components, and further contains coloring pigments, extender pigments, organic solvents, additives, etc. as necessary.

As the vehicle component, a compound having an unsaturated double bond capable of radical polymerization in the molecule can be used. Specifically, unsaturated polyester resins, unsaturated acrylic resins, unsaturated urethane resins, unsaturated epoxy resins, unsaturated polyamide resins, or these resins and ethylenic resins are used in ordinary UV-curable paints. A typical example is a mixture with a reactive diluent having an unsaturated group. In particular, the following vehicles having excellent weather resistance, flexibility, adhesion, etc. are suitable.

The vehicle has 1. The main component is an acrylic urethane oligomer, which has a urethane bond in its molecule and an unsaturated double bond that can be radically polymerized. This includes a wide range of substances that are viscous at room temperature.

For example, polyisocyanate and hydroxyl group-containing (meth)
In addition to oligomers obtained by reaction with acrylic esters, polyether-based acrylic urethane oligomers,
Also included are polyester-based acrylic urethane oligomers, polybutadiene-based acrylic urethane oligomers, and the like.

Specifically, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, quinoles diisocyanate, their isomers or excess polyisocyanate, polyester polyol, polyoxymethylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, etc. Caprolactone polyonope A compound having a polyincyanate (preferably a non-yellowing type polyisocyanate), a hydroxyl group, and an unsaturated group, such as a compound having an incyanate end, which is a reaction product of trimethylolpropane or pentaerythritol with a polyhydric alcohol. Examples include reaction products with. The compounds having a hydroxyl group and an unsaturated group include hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyethyl (meth)acrylate,
Typical examples include glycidyl (meth)acrylate.

The vehicle consists of these acrylic urethane oligomers and a reactive diluent. As reactive diluents, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (
meth)acrylate, inbornyl(meth)acrylate, tripropylene glycol diacrylate, 1,6
-Hexanediol diacrylate, tetraethylene glycol diacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(
Typical examples include meth)acrylate, ditrimethylolpropane pentaacrylate, dipentaerythl-hexaacrylate, vinyl acetate, N-vinylpyrrolidone, dimethyl(meth)acrylamide, vinyltoluene, divinylbenzene, etc., and these reaction diluents is 1 for 100 parts by weight of acrylic urethane oligomer.
It is suitable to blend 0 to 100 parts by weight.

As the photoreaction initiator, commonly used carbonyl compounds such as benzoin, benzophenone or their esters, benzoyl peroxide, acetophenone,
Jetoxyacetophenone, diphenyl disulfide, N-methyljetanolamine, 2,5-jethoxy-4-(p-tolylthio)benzenediazonium hexafluorophosphate, etc. can be used as representative examples, but opaque substances containing color pigments can be used. When applied to UV-curable coating compositions, the following acylphosphine oxide compounds with good curability or a combination thereof with the above-mentioned conventional photoreaction initiators are preferred. The acylphosphine oxide compound is a compound represented by the following general formula.

= p-c-r (1) 2 [wherein R1 is a linear or branched alkyl group having 1 to 6 carbon atoms, cyclohexyl having a total of 6 to 12 carbon atoms,
cyclopentyl-, aryl-, halogen-, alkyl-1 or alkoxy-substituted aryl group, or S- or N
- represents a 5- or 6-membered heterocyclic group (containing other carbon atoms); R2 has the same meaning as R1, and R1 and R2 may be the same or different, or have 1 carbon atom
represents an alkoxy group having ~6 carbon atoms, an aryloxy group or an arylalkoxy group having a total carbon number of 6 to 12, or R1 and R2 together with the phosphorus atom represent an alkoxy group having a total carbon number of 6 to 12;
and R3 has 2 carbon atoms.
Linear or branched alkyl group having ~18 carbon atoms, 3 to 1 carbon atoms
represents an alicyclic group having 0, a phenyl group or a naphthyl group, or an S-1O-1 or N-containing 5- or 6-membered heterocyclic group (containing other carbon atoms), and the R3 group is 1 or more a substituent or group: (wherein R1 and R2 are as defined above), and X is a phenylene group or a group having 2 carbon atoms.
represents an aliphatic or alicyclic divalent group having ~6, R1
-One or more of R3 may be olefinically unsaturated]
Specifically, 2,2-dimethylpropioyldiphenylphosphine oxide, 2,2-dimethylpentanoyldiphenylphosphine oxide, 2,2-dimethyloctanoyldiphenylphosphine oxide, methyl 2,2-dimethyloctanoyl phenylphosphine finate, 2-methyl-2-ethylhexanoyldiphenylphosphine oxide, 2.6-dimethylbenzoyldiphenylphosphine oxide, 2.6-simethoxybenzoyldiphenylphosphine oxide, 2.
6-cyclopenzoyldiphenylphosphine oxide, 2.4.6-) lyntylbenzoyldiphenylphosphine oxide, methyl 2.4.6-)'J methylbenzoylphenylphosphine oxide, 2,3.6-
Dolimethylbenzoyldiphenylphosphine oxide, 2゜4.6-Dorimethoxybenzoyldiphenylphosphine oxide, 2,4.6-Dolichlorobenzoyldiphenylphosphine oxide, 2゜4.6-
) IJ methylbenzoylnaphthyl phosphonate and the like are representative examples.

The acylphosphine oxide compound is suitably blended in an amount of 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight, per 100 parts by weight of the vehicle component.

The transparent glass powder propagates light energy into the coating, improves the curing properties of the coating, and imparts wear resistance to the resulting coating.Furthermore, the coating surface partially forms minute convexities, making it difficult to use transparent plastic. It has properties such as improved film releasability.

In order for the transparent glass powder to have the above-mentioned function, the difference between the refractive index of the transparent glass powder and the refractive index of the cured clear coating of the vehicle component must be within 0.3. In addition,
If the difference in refractive index exceeds 0.3, the light energy for curing the film will be significantly attenuated in the deep part of the film, resulting in poor curing, so is this appropriate? >Yes.

In addition, the shape of the glass powder is preferably spherical or a mixture of spherical and irregular shapes when forming a thick film of several hundred μm, whereas it is amorphous when forming a thin film of several tens of μm. Good too.

Further, the particle size of the glass powder is suitably a median particle size of 100 μm or less, preferably 0.5 to 60 μm. In addition, 100μ
When the thickness exceeds m, physical properties such as tensile strength decrease, while when the thickness decreases below 0.5 μm, the transmittance tends to decrease.

The transparent glass powder used in the present invention can be used without particular limitations as long as it satisfies the above conditions.

Usually, the refractive index N of a clear coating of a vehicle component used in an ultraviolet curable coating composition. is about 1.4 to 1.6, so soda lime glass, soda lime/lead glass, potash/lead glass, potash/lead glass, potash/soda/lead glass with a refractive index N of around 1.5 , borosilicate glass,
Specific examples include high alumina glass and potash/soda/barium glass, but it is obvious that the glass is not limited to these.

The appropriate amount of glass powder is 20 to 80% by weight in the resulting film.

In the present invention, as the coloring pigments that may be blended as necessary, ordinary inorganic/organic pigments and dyes can be used. Specifically, titanium oxide, zinc sulfide, zinc white, lead white,
Typical examples include lithopone, carbon black, oil smoke, navy blue, phthalocyanine blue, ultramarine blue, carmine FB, yellow lead, zinc yellow, hand yellow ocher, red iron, insoluble metal-containing azo dye metallic pigments, and bar pigments.

Typical extender pigments include silica sand, silicates, talc, kaolin, barium sulfate, calcium carbonate, flaky, fibrous, or hollow glass, and resin powders such as polyurethane, polyester, polyethylene, and polystyrene. It will be done.

The solvent is used to appropriately adjust the viscosity of coating or printing, and representative examples include toluene, xylene, acetone, methyl ethyl ketone, and ethyl acetate.

The colored ultraviolet curable coating composition used in the present invention consists of the components described above.

Next, the method for manufacturing the coated plate of the present invention will be explained.

First, the surface of the substrate is subjected to pretreatment such as degreasing, polishing, and plugging, or a brimer, etc., as necessary, and then an ultraviolet curable coating composition is applied (or printed) using ordinary coating means or printing means. do. A transparent plastic film is then placed over the coating. If the ultraviolet curable coating composition contains a solvent, it is desirable to cover it with a transparent plastic film after flashing off.

The transparent plastic film to be used can be used without particular limitation as long as it is made of ordinary polyethylene terephthalate, polyethylene, polyester, acrylic resin, fluororesin, etc., and the film thickness is 30 to 100 mm.
A thickness of about 0 μm is suitable, but it is not limited to this.

For the surface of the transparent plastic film that comes into contact with the coating, if you want the resulting coating to have a smooth mirror finish, a matte finish, or an uneven pattern finish, use a film with a smooth surface or a fine uneven surface, respectively. It is sufficient to use a film having a rough surface or a pattern-like uneven surface, and it is possible to manufacture a coated plate having an arbitrary coating depending on the surface morphology of the film. After covering with a transparent plastic film, the film is cured by irradiation with ultraviolet light.

As a light source used for irradiating ultraviolet rays, a low pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, a carbon arc lamp, a xenon lamp, a chemical lamp, etc. are used.

<Effects of the Invention> As described above, since the ultraviolet curable coating composition used in the present invention uses a specific glass powder, after the transparent plastic film covered on the surface of the coating is irradiated with ultraviolet rays,
It is possible to easily peel and remove the film, and therefore, it is possible to manufacture a coated plate having any coating such as mirror finish, matte finish, uneven pattern finish, etc. depending on the surface form of the transparent plastic film with high production efficiency.

In addition, since the glass powder is used, it is not affected by the ultraviolet absorption of transparent plastic films, etc.
It is now possible to sufficiently cure even a (semi-)transparent film with a thickness of several hundred μm, and when an acylphosphine oxide compound is also used as a photoreaction initiator, an opaque colored film and a thick film of several hundred μm can be obtained. However, it can be sufficiently cured and has great practical value.

<Examples> Hereinafter, the present invention will be explained in more detail with reference to Examples. In the examples, "parts" and "%" are expressed on a weight basis.

[Preparation of Acrylic Urethane Oligomer (I)] Acrylic urethane oligomer (I) having an average molecular weight of about 500 was prepared by adding 1 mol of isophorone diisocyanate and 2 mol of 2-hydroxyethyl acrylate in a conventional manner.

[Preparation of acrylic urethane olicomer (n)] 1, 6
-Hexanediol 2.1 mono to ethylene glycol 1
mol and 2.4 mol of adipic acid were subjected to a condensation reaction to produce a polyester having a molecular weight of about 1000, and the polyester was subjected to an addition reaction with 2-hydroxyethyl acrylate to 2-monoisophorone diisonoanate by a conventional method. A polyester type acrylic urethane oligomer (II) having an average molecular weight of about 1,700 was prepared.

[Preparation of acrylic epoxy oligomer (I)] 1 mole of bisphenol A type jepoxy compound (manufactured by Yuka Shell Epoxy Co., Ltd., trade name [Epicote 828J, molecular weight approximately 380]) and 2 moles of acrylic acid were subjected to an addition reaction using a conventional method to obtain an acid value of 20. Example 1 An ultraviolet curable coating composition consisting of the following formulation was applied to a black hard vinyl chloride resin plate using a 10 mil applicator, and an acrylic epoxy oligomer (I) was prepared.
The entire surface was covered with a transparent polyethylene terephthalate film (50 μm thick) with a smooth surface. Then 120W/am
The film was cured by irradiating ultraviolet rays for 2 seconds from a distance of 15 cm using a Fe-3N halide lamp.

Next, the film was peeled off by hand to produce a coated plate. The obtained coated plate had a glossy mirror finish film formed on it. Table 1 shows the results of a performance test on the obtained film and the ease of peeling the film. Note that the refractive index Nl) of the clear film obtained by excluding the soda glass powder and zinc sulfide pigment from the following formulation was 1.5.

<Composition> Acrylic urethane oligomer (I) 22 parts N-
Vinylpyrrolidone 68 soda glass powder Note 1) 50 parts zinc sulfide pigment
14 parts Note 1) Refractive index No. = 1.
52. Comparative example 1 of transparent amorphous powder with a center particle size of 5 μm In Example 1, instead of soda glass powder, refractive index ND
A coated plate was produced in the same manner as in Example 1 except that transparent amorphous lead glass powder having a particle size of 2.2 and a center particle size of 5 μm was used. Table 1 shows the results of a performance test on the obtained film and the ease of peeling the film.

Comparative Example 2 A coated plate was produced in the same manner as in Example 1 except that calcium carbonate was used instead of glass powder.

Table 1 shows the results of a performance test on the obtained film and the ease of peeling the film.

Comparative Example 3 Example 1 except that Calciramula carbonate was used instead of the glass powder and an acetophenone photoreaction initiator was used instead of 2.4.6-)limethylbenziyldiphenylphosphine oxide. A coated plate was produced in the same manner.

Table 1 shows the results of a performance test on the obtained film and the ease of peeling the film.

Example 2 In Example 1, 2,4,6-1-IJ methylbenzoyldiphenylphosphine oxide was replaced with 2,6-
A coated plate was produced in the same manner as in Example 1 except that cymethoxybenzoyldiphenylphosphine oxide was used. Table 1 shows the results of a performance test on the obtained film and the ease of peeling the film.

Example 3 In Example 1, acrylic urethane oligomer (II) was used instead of (I), and 2.4.6-)lyntylbenzoyldiphenylphosphine oxide was used instead of 2.4.6-)lyntylbenzoyldiphenylphosphine oxide.
A coated plate was produced in the same manner as in Example 1 except that 6-cyclopenzoyldiphenylphosphine oxide was used.

Table 1 shows the results of a performance test on the obtained film and the ease of peeling the film.

Note 2) Goban adhesion test Note 3) Test by immersing the coated plate in water for one week. Property 4) O: Can be peeled off by hand without resistance.

×: There was considerable resistance to peeling off by hand, and some parts of the film were damaged.As is clear from Table 1, the film obtained by the method of the present invention has good adhesion and water resistance, and the film is easy to peel. there were.

On the other hand, Comparative Example 1, which used glass powder with a refractive index difference of 0.4 or more from the clear coating film, and Comparative Examples 2 and 3, which did not contain glass powder, both had poor adhesion and water resistance, and the film did not peel. Sexuality was also poor.

Example 4 An ultraviolet curable coating composition having the following formulation was applied to a white metal plate using a 15 mil applicator, and the entire surface was covered with a transparent polyethylene terephthalate film (thickness: 200 μm) having a finely roughened surface. Then 120W/
The coating was cured by irradiating ultraviolet rays for 2 seconds from a distance of 15 cm using a 1.5 cm Fe-3N halide lamp.

Next, the film was peeled off by hand to produce a coated plate. The resulting coated plate was formed with a matte finish coating.

Table 2 shows the results of a performance test on the obtained film and the ease of peeling the film.

The refractive index N of the clear coating was 1.5 except for the following blended soda glass powder and extender pigment.

<Composition> Acrylic epoxy oligomer III 25fE
Trimethylolpropane triacrylate 7 parts Acetophenone photoinitiator 1 part Soda lime glass beads Note 5) 53aE precipitated barium sulfate 14 parts Note 4) Refractive index ND = 1.53
, transparent spherical powder with a center particle size of 50 μm Comparative Example 4 A coated plate was obtained in the same manner as in Example 4, except that lead glass beads with a refractive index ND of 2.2 were used instead of soda lime glass beads. .

Table 2 shows the results of a performance test on the obtained film and the ease of peeling the film.

Comparative Example 5 A coated plate was obtained in the same manner as in Example 4 except that calcium carbonate was used instead of soda lime glass beads.

Table 2 shows the results of a performance test on the obtained film and the ease of peeling the film.

As is clear from Table 2, the coating obtained by the method of the present invention had good adhesion and water resistance, and the film was easily peeled off.

On the other hand, both Comparative Example 4, which used glass beads with a refractive index difference of 0.4 or more from the clear film, and Comparative Example 5, which did not contain glass beads, had poor adhesion and water resistance, and also had poor film releasability. Met.

Claims (2)

[Claims] (1) An ultraviolet curable coating composition containing an ultraviolet ray polymerizable vehicle component and a transparent glass powder whose refractive index difference between the vehicle component and the cured clear coating is within 0.3 is applied to the substrate surface, and then A method for producing a coated plate, which comprises covering the coated surface with a transparent plastic film and then irradiating the coated surface with ultraviolet rays to form a cured film. (2) The ultraviolet curable coating composition is a colored ultraviolet curable coating composition that uses an acylphosphine oxide compound as a photoreaction initiator and contains a colored pigment. A method for manufacturing painted plates.