JPH02164482A - Method for forming multi-hue pattern film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention has a soft feel and can be applied to coating methods that are subjected to shearing force such as roll coater or screen printing, thereby forming a uniform multi-colored coating film. The present invention relates to a method for forming a multicolored pattern coating film using an ultraviolet curable paint.

[Prior art and problems to be solved] Conventionally, there has been a method of forming a multi-colored pattern coating film by spray painting a multi-colored pattern forming paint containing dispersed colorant particles. It is known as a typical example.

However, with this method, although a uniform multicolored pattern coating film is obtained, the unevenness of the colorant particles on the surface of the coating film gives it a rough feel and is soft to the touch. There were problems in that the feel to the touch was poor, and because the outline of the pattern created by the colorant particles was clear, the contrast was strong and the product felt hard.

In addition, since spray painting was used, there was a lot of paint scattering, which not only created a poor painting work environment, but also caused waste due to paint loss.

Therefore, a method of forming a multi-colored paint film using a roll coater, screen printing, etc., which causes less paint loss and can be painted in a factory, is considered.

However, roll coaters, screen printing, etc. apply a high shearing force during coating, which causes the colorant particles to shift due to movement, resulting in a problem that the resulting multicolored pattern coating film tends to be non-uniform. Therefore, the current situation is that one-coat painting is rarely used. In addition, as a method for forming a two-color, multi-colored pattern paint film by roll coater painting, a certain colored paint is applied to the entire surface of the uneven base material or the uneven paint film, and then a paint of a different color from the colored paint is applied only to the convex parts. A coating method is known, but this method has problems such as the resulting multicolored pattern has clear outlines, lacks a soft appearance, and requires double coating.

Furthermore, the paints used for these are dried at room temperature, forced drying or baked drying, and it usually takes several tens of minutes to several days to obtain a cured film, resulting in poor productivity.

On the other hand, in recent years, with social demands such as pollution-free and resource saving,
The development of paints that are solvent-free or contain a small amount of organic solvents is desired.

Therefore, it is conceivable to use an ultraviolet curable paint that has a short curing time of several tens of seconds or less and is solvent-free or has a small amount of solvent as a paint for forming multicolored patterns.

However, when colorant particles to form a multi-colored paint film are included in an ultraviolet curable paint, the colorant particles absorb or block ultraviolet rays, preventing the ultraviolet rays from reaching the inside of the paint film, causing the inside of the paint film to harden. Therefore, ultraviolet curing paints containing colorant particles have not been put to practical use as paints for forming multicolored patterns.

In view of the current situation, the inventors of the present invention have made extensive studies to solve the above problems, and have found that the present inventors have created a product that has a soft appearance and feel, and can be coated in one coat using a roll coater, screen printing, or other means. The inventors have discovered a method for forming a coating film with a uniform multicolored pattern that can be cured in a short time after irradiation with ultraviolet rays, leading to the present invention.

<Means for Solving the Problems> The present invention provides an ultraviolet curable coating material, in which colorant particles and hollow particles not impregnated with liquid are dispersed, and which contains an acylphosphine oxide compound as a photoreaction initiator, on the surface of a substrate. The present invention relates to a method for forming a multi-colored pattern coating film, in which the coating film is cured by applying ultraviolet rays.

The present invention will be explained below.

The ultraviolet curable paint for forming multicolored patterns used in the present invention contains an ultraviolet polymerizable vehicle, a photoreaction initiator, colorant particles, and hollow particles that are not impregnable with liquid as essential components.
Furthermore, additives such as coloring dyes and pigments, extender pigments, solvents, thickeners, dispersants, antifoaming agents, and film-forming aids are blended as necessary.

As the vehicle component, a compound having an unsaturated double bond capable of radical polymerization in the molecule can be used. Specifically, we use unsaturated polyester resins, unsaturated acrylic resins (removal resin, unsaturated urethane resins, unsaturated epoxy resins, unsaturated polyamide resins, or combinations of these resins) that are used in ordinary UV-curable paints. A typical example is a mixture with a reactive diluent having an ethylenically unsaturated group, but it is especially good for adhesion to substrates, weather resistance, and curability under a wide range of ultraviolet irradiation conditions (quick drying). The following excellent vehicles are preferred.

The vehicle has an acrylic urethane oligomer as a main component, and the acrylic urethane oligomer has a urethane bond in the molecule and an unsaturated double bond capable of radical polymerization, and has an average molecular weight of several hundred to about 1000 yen. 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, inphorone diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, their isomers or excess polyisocyanate and polyester boronopepolyoxymethylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, Cabrolactone Borionope A combination of a polyisocyanate (particularly preferably a non-yellowing type polyisocyanate), such as a compound having an isocyanate end, which is a reaction product with trimethylolpropane, pentaerythritol, etc., and a compound having a hydroxyl group and an unsaturated group. Examples include reaction products. The compounds having a hydroxyl group and an unsaturated group include hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate,
Hydroxyethyl (meth)acrylate, glycidyl (
Typical examples include 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
Representative examples include (meth)acrylate, ditrimethylolbrohannetaacrylate, dipentaerythritol hexaacrylate, vinylacetate N-vinylpyrrolidone, dimethyl(meth)acrylamide, vinyltoluene, divinylbenzene, etc., and these reaction dilutions The agent is preferably blended in an amount of 10 to 100 parts by weight per 100 parts by weight of the acrylic urethane oligomer.

As the photoreaction initiator, an acylphosphine oxide compound is used.

It should be noted that if UV-curable paints contain components that absorb or block UV rays, such as colorant particles, the UV rays will not reach the inside of the paint film, resulting in poor curing inside the paint film. It was unexpectedly discovered that among certain photoreaction initiators, the use of the acylphosphine oxide compound as a photoreaction initiator results in sufficient curing. This acylphosphine oxide compound is a compound represented by the following general formula.

[In the formula, R1 is a linear or branched alkyl group having 1 to 6 carbon atoms, and a cyclohexyl group having 6 to 12 carbon atoms.
, cyclopentyl-, arylhalogen-, alkyl-
, alkoxy-substituted aryl group, or an S- or N-containing 5- or 6-membered heterocyclic group (containing other carbon atoms), R2 has the meaning of R1, and R1 and R2 may be the same or different, or an alkoxy group having 1 to 6 carbon atoms or a total carbon number of 6 to 1
or R1 and R2 together with the phosphorus atom to which they are bonded form a ring moiety having 2 to 12 carbon atoms; and R3 represents an aryloxy or arylalkoxy group having 2 to 2 carbon atoms; a linear or branched alkyl group having ~18 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, a phenyl group or a naphthyl group, or S-10-
or represents an N-containing 5- or 6-membered heterocyclic group (containing other carbon atoms), in which the R group has one or more substituents,
or a group in which R1 and R2 are as defined above, and X represents a phenylene group or an aliphatic or cycloaliphatic divalent group having 2 to 6 carbon atoms, and R1- One or more of R3 may be olefinically unsaturated. ] The acylphosphine oxide compound is suitably blended in an amount of 0.1 to 5 parts by weight, particularly preferably 0.2 to 3 parts by weight, per 100 parts by weight of the vehicle component.

Optionally α,α-dimethyl-α-hydroxyacetophenone, hydroxycyclohexylacetophenone, benzyldimethyl ketal, α,α-dimethyl-α-morpholineaceto p-methylthiophenone, α,α-diethyl-α-dimethylaminoaceto-p-morpho It is also possible to use a common photoreaction initiator such as linophenone.

Typical examples of the colorant particles include hard or soft colorant particles such as powder coatings, colored plastic particles, microcapsules containing colored liquid m1, etc., but they do not dissolve in the paint. , it can be used without particular restrictions as long as it is stably dispersed.

In particular, soft or flexible colorant particles in the presence of hollow particles, which will be described later, will only deform even if a crushing force is applied during painting, and will be difficult to move along with the forward movement of the paint sprayer. Therefore, it is desirable because it will be uniformly distributed in the coating film and a uniform multicolored pattern will be easily obtained.

The particle size of the colorant particles should be approximately 20 to 20 mm, considering stability in the paint, ease of pattern recognition, ease of curing of the paint film, etc.
Appropriately, the thickness is about 500μ, preferably about 30 to 200μ.

The hollow particles function as a buffer material, suppress the movement of the colorant particles as the coating machine advances, and compensate for the poor mechanical stability of the colorant particles.
It is also used by coating means such as screen printing because it enables the formation of a uniform multi-colored coating film.

In addition, since hollow particles are hollow, their specific gravity is small (for example, true specific gravity is 0.5 or less, preferably 0.2 or less). Therefore, after painting, while the paint film is in a wet state, It floats and is mainly distributed on the surface of the coating film, and the resulting coating film has no roughness and has a soft touch feeling when touched with the hand.

Furthermore, if the hollow particles are transparent, there is a difference in refractive index between the internal gas of the hollow particles and the outer wall, and if the particles are colored, the outer wall film is thin and the scavenging power is small, so that The color clarity of the colorant particles visible through the distributed hollow particles is moderated, and therefore the resulting multicolored pattern has a soft tone, resulting in a coating film with a soft appearance.

As mentioned above, hollow particles must not be impregnated with liquid in order to be able to float on the surface of the paint film.For example, porous particles such as Shirasu balloons absorb liquid and have a specific gravity similar to that of paint. It is not suitable because it becomes difficult to float.

Typical examples of such hollow particles include hollow particles of vinylidene chloride-acrylonitrile copolymer, acrylic acid ester-styrene copolymer, etc., and hollow glass beads. The shape of the hollow particles is
Spherical particles are preferable, and the particle size is 200 μm from the viewpoint of coating film appearance, buffering material function, coating stability, and coating workability.
Hereinafter, preferably about 10 to 100 microns is suitable.

The blending amount of the colorant particles in the ultraviolet curable paint is 0.5
A suitable amount is 40% by weight (based on solid content), preferably 5 to 30% by weight, and within this range, a coating film with an appropriate multicolored pattern can be obtained, and the stability of the coating material is good.

Further, the blending amount of the hollow particles is 0.01 to 15% by weight.
(in terms of solid content), preferably 0.1 to 10% by weight, and within this range a soft, textured, uniform multicolored pattern coating film can be obtained.

The above-mentioned colored dyes and pigments do not necessarily need to be blended, but can be used for the purpose of adjusting the color of the coating film or improving the design.

Coloring dyes and pigments include organic dyes and pigments such as phthalocyanine, anthraquinone, perylene, azo, isoindolinone, and quinacridone, inorganic pigments such as carbon black and transparent iron oxide, aluminum powder, mica powder, etc. Typical examples include metallic pigments.

The extender pigments are used to improve coating performance or as extenders, and specifically include silica sand, silicates, talc, kaolin, barium sulfate, calcium carbonate,
Typical examples include powdered, flaky, and fibrous glass, and resinous powders such as polyurethane, polyethylene, and polystyrene.

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

Next, a method for forming a multicolored pattern coating film using the ultraviolet curable paint of the present invention will be explained.

The coating film can be formed on various substrates such as metal, wood, plastic, glass, ceramics, concrete, and paper.

The ultraviolet curable paint used in the present invention not only has a soft feel, design, heat insulation, and soundproofing properties, but also has the characteristics of a radically polymerizable cured coating film, such as abrasion resistance, scratch resistance, water resistance, Since a coating film with excellent chemical resistance etc. can be obtained, it can be particularly suitably used for the interior and exterior of buildings. These substrates may be subjected to a surface treatment such as sealing treatment, polishing treatment, coloring treatment, etc. as necessary, and may also have an uneven surface.

Conventional spray painting, etc., is naturally possible on the surface of such substrates, but roll coaters, flow coaters, knife coaters, brushes,
Even with coating (printing) methods that apply shearing force, such as gravure, offset, offset gravure, and screen, a uniform multicolored pattern can be formed in one coat.

It is appropriate to apply the film to a thickness of 50 to 500 μm (dry film thickness).

Next, the multicolored pattern coating film is cured by irradiation with ultraviolet rays.

Note that 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.

Further, in the case of a film thickness (for example, 100 to 500 μm), the input is 80 W/CIn or more, preferably 120 W/Cm or more, and the metal halide lamp is particularly suitable as the light source.

<Effects of the Invention> Since the ultraviolet curable paint for forming multicolored patterns used in the present invention contains hollow particles, the hollow particles can be used to buffer even coating methods that apply shearing force such as roll coaters and screen printing. It acts as a material, provides a multi-colored paint film in which dispersed colorant particles are uniformly distributed, and also has good coating workability due to its low specific gravity.

In addition, after painting, hollow particles with low specific gravity float to the surface of the paint film, so the resulting paint film has a soft appearance and feel, and has excellent heat retention, heat insulation, and sound insulation properties. It will be done.

Furthermore, since an acylphosphine oxide compound is used as a photoreaction initiator, there is little decrease in the intensity of light energy even though there is scattering, diffusion, and absorption of light energy incident from the surface layer of the paint film, and therefore the lower layer of the paint film It is possible to obtain a cured coating film that cannot be obtained with conventional photoreaction initiators that are commonly used.

The multicolored pattern of the present invention is the color of the ultraviolet curable paint (which may be clear), the color of the colorant particles (the colorant particles may be a combination of two or more colors), or the color of the hollow particles. By combining these, a multi-colored coating film with various color combinations can be obtained.

<Examples> Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, "parts" in the examples are based on weight.

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

[Preparation of acrylic urethane olicomer (II)] 1.
2.1 moles of 6-hexanediol, 1 mole of ethylene glycol, and 2.4 moles of adipic acid were subjected to a condensation reaction to produce a polyester having a molecular weight of 1000. 1 mol of said polyester, 2 monobenzate of isophorone diifcyanate 2-
A polyester type acryl urethane oligomer (I[) having an average molecular weight of 1,700 was prepared by addition reaction with 2 moles of hydroxyethyl acrylate in a conventional manner.

[Preparation of acrylic urethane oligomer (IID)] Bisphenol A-type jepoxy compound [trade name "Ebiko" 828J, manufactured by Yuka Shell Epoxy Co., Ltd., molecular weight approximately 380] 1 mole and 2 moles of acrylic acid were subjected to an addition reaction in a conventional manner to obtain an acid value of 20. Acrylic epoxy oligomer (III) was prepared.

[Preparation of yellow colorant particle dispersion (A>)] Lead chromate
20 parts calcium carbonate 10 parts tol
en 10 evil note 1
) Manufactured by Dainippon Ink Chemical Industry Co., Ltd. Product name: Acrylic 80
1" Add 40 parts of yellow organic solvent-based paint of the above formulation to 50 parts of water.
10.3 parts of dispersant [Demol PJ (trade name manufactured by Kao Corporation) and thickener [
0.3 part of Natrazol 250MRJ (trade name, manufactured by Harkiniles) was added to prepare a dispersion (A) of yellow colorant particles having an average particle size of about 80 μm.

Example 1 Acrylic urethane oligomer (1) 60 parts Yellow colorant particle dispersion (A) 20x2) Matsumoto Yushi Pharmaceutical Co., Ltd., trade name "Microsphere-F-80E"
DJ (polyvinylidene chloride system; particle size 20 to 80μ; true specific gravity 0.02) A dry film of ultraviolet curable paint consisting of the above formulation was coated on a hard vinyl chloride resin plate using a sponge roll coater.
Apply the coating so that it becomes μ, flash it off with hot air at 60°C for 3 minutes, and then heat it with a metal halide lamp (manpower: 120 W/cm).
) below 100[+1111 position, passing speed 5
The coating film was cured by ultraviolet light, which was passed through the film at a speed of m/min.

Example 2 Acrylic urethane oligomer (II) 60 parts N
- 40 parts of vinyl pyrrolidone 40 parts of vinyl acetate An ultraviolet curable paint consisting of the above formulation was applied with a knife coater to a dry film thickness of 120 μm, and after flashing off with hot air at 60°C for 1 minute, the same procedure as in Example 1 was applied. The coating was cured.

Example 3 Acrylic epoxy oligomer (In) 609
Note 3) Product name rQ=C manufactured by Philadelphia Quartz Co.
EL300J (particle size 10-180μ, true specific gravity 0.21) A UV-curable paint consisting of the above formulation was applied in a pattern to a metal plate using screen printing to give a dry film thickness of 100μ, and after setting for 3 minutes, Metal halide lamp (input 120
The coating film was cured by ultraviolet irradiation by passing the coating film from a position 10010+11 below W/c+++ at a passing speed of 7 m/min.

Comparative Example 1 A coating film was formed in the same manner as in Example 2 except that the hollow resin particles were removed using the same ultraviolet curable paint.

Comparative Example 2 The same ultraviolet curable paint as in Example 2 was used except that Shirasu balloons were used instead of the hollow resin particles.
A coating film was formed in the same manner.

Comparative Example 3 Same ultraviolet curing type as in Example 2 except that 3 parts of α,α-dimethyl-α-hydroxyacetophenone was used instead of 2,4゜6-drimethylbenzoyldiphenylphosphine oxide as a photoreaction initiator. A coating film was formed in the same manner using a paint.

Comparative Example 4 A coating film was formed in the same manner as in Comparative Example 3, except that 10 parts of α,α-dimethyl-α-hydroxyacetophenone was used, using the same UV-curable paint.

The pattern form, pattern uniformity, soft feel, and adhesion to the substrate of the coating films obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were as shown in Table 1.

As is clear from Table 1, the coating films obtained in Examples 1 to 3 of the present invention had a spotted multicolored pattern in which colorant particles were uniformly distributed, and the color of the colorant particles was relaxed and soft. It had a deep color and soft texture, and also had good adhesion to the base material.

On the other hand, the coating films obtained in Comparative Example 1, in which no hollow particles were used, and in Comparative Example 2, in which liquid-impregnable Shirasu balloons were used instead of hollow particles without liquid-impregnable properties, both had a distribution of colorant particles. The coating was uneven and had a variegated pattern, and colorant particles were visible on the surface of the coating, giving it a lack of soft feel. Furthermore, in all of the coating films obtained in Comparative Examples 3 and 4 in which a photoreaction initiator other than the acylphosphine oxide compound was used, the lower layer of the coating film showed insufficient curing and poor adhesion.

Claims (1)

[Claims] An ultraviolet curable paint in which colorant particles and hollow particles that cannot be impregnated with liquid are dispersed and contains an acylphosphine oxide compound as a photoreaction initiator is applied to the surface of the substrate, and a coating film is formed by irradiating it with ultraviolet rays. A method for forming a multi-colored paint film that is cured.