JPH02284676A - Formation of finely rugged coating film - Google Patents

Abstract

PURPOSE:To improve interfacial adhesion by laminating a top coat having a specified compsn. on a base coat having a specified compsn. formed on the surface of a substrate, pressing a specified finely embossed sheet on the top coat while the top coat has flowability and curing the top coat. CONSTITUTION:An anticorrosive colored base coat contg. methoxymethylol melamine as a cross-linking agent is formed on the surface of a substrate made of an inorg. material such as a metal or glass or an org. material such as plastics, wood or fiber. A top coat of paint curable with active energy beams is formed on the base coat and a finely embossed sheet of polyethylene terephthalate, PVA, etc., is pressed on the top coat while the top coat has flowability. The top coat is then cured by irradiation with active energy beams and the finely embossed sheet is stripped. A finely rugged coating film is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for forming a high-quality matte finely uneven coating film on the surface of a base material such as metal, plastic, wood, paper, or the like. Furthermore, the present invention provides a method for forming a coating film with minute irregularities that is useful when applied to pre-coated steel plates such as roofs, indoor walls, partition materials, metal containers, and outer panels of electrical appliances.

[Conventional technology]

As a means of forming a matte coating film on the base material surface of various materials,
BACKGROUND ART A method has long been known in which materials such as silicon oxide fine particles, extender pigments, or organic resin fine powders are mixed into paint components to create an uneven pattern on the surface of the paint film. However, this method has the disadvantage that the particle material settles in the coating state, and the formed coating film has poor leveling properties, making it difficult to obtain a desired uneven pattern uniformly and continuously.

As a technique for forming a matte uneven coating film without such defects, an uncured UV-curable resin coating film is created on the base material surface, C. , a method has been proposed in which the sheet is cured by passing through the sheet with light, radiation, etc. (Japanese Unexamined Patent Publications No. 61-200878, No. 62-14478).
No. 3, JP-A No. 64-51174, etc.), and
JP-A-64-58373 discloses a method for producing a matte synthetic resin molded product by transferring C.i. made of an ionizing radiation curable resin onto a peeling surface having minute irregularities.

In these prior art techniques, the original purpose of irradiating active energy rays through the pressure bonding surface of the transparent sheet is to improve the curability of active energy ray-curable paints. That is, the pressure bonding of the sheet in this case is carried out in order to block the presence of oxygen, which reduces the curability of the active energy ray-curable coating material.

In addition, in the prior art, the resin was formed only with a coating film that was cured by irradiation with active energy rays, so the resin cured within an extremely short period of time through radical polymerization. However, curing is completed in about 60 seconds. It is well known that curing in such a short period of time results in large shrinkage during curing, which impairs adhesion to the substrate.

Another point to consider is that the curing of the entire coating film will not progress smoothly unless the active energy rays are transmitted through it, and for this reason, active energy ray-cured paints according to the prior art are generally transparent or formed with a rear coating film. Currently, white coatings are only used on some cans. Therefore, colored coatings containing pigments or other materials that are difficult for active energy rays to pass through are considered unsuitable. ing.

However, in reality, the mainstream is the formation of colored coatings for the purposes of decoration, corrosion protection, etc., and if these coatings cannot be cured with active energy rays, they are not suitable as a manufacturing means.

Therefore, the object of the present invention is to form an active energy ray-cured coating film on the base coated coating surface with anticorrosive coloring and methoxylated methylolmelamine as a crosslinking agent as an entire coating system, thereby effectively promoting micro-irregularities F! ! The present invention provides a method for forming a film.

However, a problem in forming an active energy ray-cured coating film on an anticorrosive colored coating film lies in the adhesion of the interface. Normally, active energy ray-curable resins cure for a short time, resulting in large volume shrinkage during curing and poor wettability to the surface of the coated object before curing, making it difficult to obtain sufficient interfacial adhesion.

Another object of the present invention is to improve the adhesion between the base coat and the active energy ray-cured paint.

[Means to solve the problem]

In order to achieve the above object, the method for forming a finely uneven coating film according to the present invention involves forming a base coat with an anti-corrosive color on the base material surface using methoxylated methylolmelamine as a crosslinking agent, and then a top coat with an active energy ray-curable paint. After forming, while the top coat maintains its fluidity, a micro-convex sheet made of one or more of polyethylene terephthalate, polyvinyl alcohol, and nitrocellulose is bonded,
The structural feature is that after the top coat is cured by irradiation with active energy rays, the minute convex sheet is peeled off.

The base materials of the present invention include metals such as iron, zinc, zinc alloy plated steel sheets, stainless steel, copper, or alloys thereof, inorganic materials such as glass, cement, and concrete, FRP, polyethylene resin, polypropylene resin, and ethylene. - Plastics such as vinyl acetate copolymer resins, polyamide resins, polyacrylic resins, polyester resins, ethylene-polyvinyl alcohol copolymer resins, vinyl chloride resins, vinylidene chloride resins, polycarbonate resins, polyurethane resins, and organic materials such as wood and fibers. Various materials such as materials or materials with coating layers are targeted.

Chemical conversion treatments (zinc phosphate treatment,
It is used after being appropriately subjected to surface treatments such as chromate treatment, silane treatment), plasma treatment, plating treatment, and undercoating including rust prevention treatment.

For the base coat formed on the surface of these substrates, an anti-corrosive coloring thermosetting resin or thermoplastic resin coating having processability and weather resistance depending on the application is used.

Preferred base coat resins include the following polyester or acrylic resins.

Raw materials for polyester resin include polyhydric alcohols such as ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, neopentyl glycol, 1,2-11,8.2.3-11,4-, and butane. Diol, 1.5-bentanediol, 1.6-hexanediol, hydrogenated bisphenol A1 hydroxyalkylated bisphenol A11.4-cyclohexane dimetatool, 2.2-dimethyl 3-hydroxypropyl-
2,2-dimethyl-3-hydroxypropione-1-(
BASHPN), N, If-bis-(2-hydroxyethyl)dimethylhydantoin, polytetramethylene ether glycol, polycaprolactone polyol, glycerin, sorbitol, annitol, trimethylolethane, ]-limethylolpropane, trimethylolbutane, hexanediol , pentaerythritol, dipentaerythritol, tris-(hydroxyethyl)isocyanate, and the like can also be used in combination.

In addition, as polybasic, phthalic acid, phthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, methyltetrahydrophthalic acid, methyltetrahydrophthalic anhydride,
Himic anhydride, trimellitic acid, trimellitic anhydride, pyromellitic acid, anhydride and romellitic acid, isophthalic acid, terephthalic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, Succinic acid, succinic anhydride, lactic acid, dodecenyl succinic acid, dodecenyl succinic anhydride, cyclohexane-1,
It is also possible to use a combination of one or more polybasic acids such as 4-dicarboxylic acid and endo-acid anhydride.

If necessary, an alkyd resin to which flexibility is imparted by adding up to about 30% of oil or fat or fatty acid can be used in combination with the resin.

The acrylic resin can be polymerized, for example, from the following monomers by a conventional method.

(1) Ethylene monomers having a nohydroxyl group such as hydroxylmethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and N-methylolacrylamine (2) ) Ethylene monomers having a carboxyl group such as (meth)acrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, (3)
Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-acrylate - Said monomers such as (meth)acrylic acid alkyl esters such as octyl and n-dodecyl acrylate (1
) and (2) and copolymerizable ethylenic monomers, (meth)acrylonitrile, styrene, etc. are used.

As the crosslinking agent, methoxylated methylolmelamine resin is used. Among the melamine-formaldehyde resins that are commonly used melamine resins, methoxylated methylol melamine resins represented by the following structural formula function effectively to provide adhesion to active energy ray-cured coatings.

In the structural formula F, n is O-4, R is -11, CH
, OH1~C1l! OCH, and -H is O
~1.5, the ratio of C11zOH/-C11xOCH+ is 1
72 to 076 are particularly effective, and resins having these ratios can be easily obtained by a method of synthesizing methoxylated methylolmelamine resin.

In this case, if n exceeds 5, the molecular weight of the resin will be too large and the physical performance of the cured coating will deteriorate, and if -H exceeds 1.5, the adhesion to the active energy cured coating will deteriorate. Moreover, if the ratio of -CHzOH/-CHxOCHs exceeds 1/2, the self-crosslinking reaction of the methoxylated methylolmelamine resin will proceed, resulting in deterioration of the performance of the cured coating film.

The blending ratio of polyester resin or acrylic resin/methoxylated methylolmelamine resin is 100 in terms of solid content weight ratio.
/40-5, preferably 100/30-15. If the compounding ratio of methoxylated methylol melamine resin exceeds 40 parts, curing will progress too much and 5M blueness and processability will be inhibited, while if it exceeds 5 parts by weight, curing will not be achieved and sufficient coating performance will not be achieved. difficult to obtain.

The base coat resin used in the present invention includes olefin resins such as polyethylene and polypropylene that are commonly used in the paint field, vinyl monochloride, vinyl acetate, vinylidene chloride, vinyl resins copolymerized with these, and cellulose resins. Thermoplastic resins such as acetal resins, alkyd resins, and chlorinated rubber resins can also be used.

Pigments used to form colored coatings include titanium dioxide, phthalocyanine blue, phthalocyanine green, quinacridone, indanthrone, isoindolinone, perylene, anthrapyrimidine, carbon black, benzimidacylon, graphite, and yellow. iron oxide,
Coloring pigments such as red iron oxide, and in some cases extender pigments such as barium sulfate and aluminum silicate, mica pigments, and/or aluminum foil, bronze foil, tin foil, gold foil, silver foil,
1 selected from bright pigments such as titanium metal foil, stainless steel foil, alloy foil such as NiCu, metal foil coated with plastic, metal foil such as foil-like phthalocyanine blue, etc.
Use more than one species. These pigment components are desirably blended in an amount of 2 to 150 parts by weight based on 100 parts by weight of the resin.

As organic solvents there may be mentioned any organic liquids or liquid mixtures customarily used in paints, for example aromatic hydrocarbons such as toluene or xylene, aliphatic hydrocarbons such as n-hexane or heptane. Petroleum fractions of various boiling point ranges consisting primarily of aliphatic hydrocarbons and containing some aromatic hydrocarbons, esters such as butyl acetate, ethylene glycol diacetate, 2-ethoxyethyl acetate, acetate and methyl isobutyl ketone. Ketones and alcohols such as butyl alcohol are used.

Other additives include curing catalysts such as dodecylbenzenesulfonic acid, ultraviolet absorbers such as benzophenol, antioxidants such as phenol and sulfide, surface conditioners such as silicone and organic polymers, anti-sagging agents, It is desirable to use additives such as thickeners in an amount of 0.1 to 5% in the paint, as this is effective in improving paint performance and coating film performance.

The anticorrosive colored base coat paint of the present invention is a fluid material obtained by blending the above-mentioned components according to ordinary paint manufacturing techniques.

To coat the above paint, usual methods such as brushing, squeezing, dipping, and spraying can be used.The viscosity required for the composition differs depending on the coating method, but the selection and combination of each component can be used. It can be adjusted by matching. Furthermore, if particularly necessary, the viscosity of the composition may be adjusted using an organic solvent such as acetate or xylene.

The dry film thickness of the base coat formed is 8-200μ,
Preferably it is in the range of 10 to 100 μm. Specifically, when the base material is a pre-coated steel plate, the base material is 10 to 20μ, 20 to 50μ for a post-coated steel plate, and 20μ for a plastic material.
For ~50n1 paper, it is desirable to set it to 10~201M.

A top coat made of active energy ray-curable paint is formed on the base coat surface thus formed.

Active energy ray-curable paints are: - For boat fishing, the main components are polymers, oligomers, and nitrates that have radically polymerizable double bonds in their structure as film-forming components.
It also contains non-reactive polymers, organic solvents, wanks, and other additives as necessary.

Preferred for the purpose of the present invention are those in which the coating film-forming resin has an acrylate-based functional tmM, such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins,
Oligomers or prepolymers such as spiroacetal resins, polybutadiene resins, polythiol polyene resins, (meth)acrylates of polyfunctional compounds such as polyhydric alcohols, and ethyl (meth)acrylate as a reactive diluent.
Monofunctional monomers such as ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidine, etc., as well as polyfunctional monomers such as trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, Tribrobylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ■, 6-hexine diol di(meth)acrylate, neopentyl glycol It contains a relatively large amount of di(meth)acrylate and the like.

By using such a polyfunctional (meth)acrylate active energy curable paint, it is possible to finally form a cured resin layer with excellent surface hardness, transparency, abrasion resistance, scratch resistance, etc. Furthermore, if such a cured resin layer is required to have high flexibility or shrinkage resistance, an appropriate amount of thermoplastic resin such as non-reactive acrylic resin or various types of Wanx may be added to the above-mentioned curable paint. These demands can be met by adding .

In order to make the above-mentioned curable paint into an ultraviolet curable paint, acetophenones, benzophenone, Michler benzoyl benzoate, α-
Amyloxime ester, tetramethylthiuram monosulfide, thioxanthone, and a photosensitizer such as dobutylamine, triethylamine, tri-n-butylphosphine, etc. can be used in combination.

Various grades of ionizing radiation curable coatings such as electron beam or ultraviolet ray curable coatings as described above are known, and any of them can be easily obtained from the market and used in the present invention.

These active energy ray-curable paints include, for example, plate coating method, gravure coating method, drawer coating method, knife coating method, reverse roll coach ink method, sub-no coating method, offset gravure coating method, kiss coating method, etc. The above synthetic resin film can be coated by any coating method, but gravure coating methods, reverse roll coating methods, offset gravure coating methods, etc., which are particularly excellent in coating thickness accuracy, coating surface smoothness, etc., are suitable. .

As a reactive diluent, one type or 21 or more monofunctional compounds having one polymerizable unsaturated group in the molecule that causes a reaction with active energy rays can be used together with the above polyfunctional compounds, if necessary. . Although monofunctional compounds are effective in adjusting the viscosity of coating compositions, they tend to reduce curability, so when used in combination, it is necessary to consider the amount ratio with polyfunctional compounds. Preferably a polyfunctional compound:
It is preferable to use the monofunctional compounds in a weight ratio of 1:3 to 2:1.

Specific examples of monofunctional compounds include the above-mentioned acrylic acid alkyl esters, methacrylic acid alkyl esters, addition reaction products of fatty acids and acrylic acid or methacrylic acid ester monomers having an oxirane structure (for example, stearic acid and glycidyl methacrylate-1. (addition reaction product), addition reaction product of an oxirane compound containing an alkyl group having 8 or more carbon atoms and acrylic acid or methacrylic acid (for example, those described in Japanese Patent Nos. 583185 and 609322), styrene, α-methylstyrene, 0-methylstyrene, [methylstyrene, p-methylstyrene, p-t
ert-butylstyrene, benzyl acrylate, hensyl methacrylate, hydroxyalkyl acrylate (hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, etc.), hydroxyalkyl methacrylate (hydroxymethyl methacrylate, hydroxyethyl methacrylate, methacrylate) hydroxypropyl methacrylate, hydroxybutyl methacrylate, etc.), tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentyl acrylate, Cyclopentyl methacrylate-1, dicyclopentyloxyethyl acrylate, 2-methoxyethyl acrylate, 2-methoxyethyl methacrylate-1, 2
-Ethoxyethyl acrylate, 2-ethoxyethyl methacrylate, dipropylene glycol monomethyl ether monoacrylate, dipropylene glycol monomethyl monomethacrylate, diethylene glycol monomethyl ether monoacrylate, diethylene glycol monomethyl ether monoacrylate, triethylene glycol monomethyl ether monoacrylate, triethylene glycol Examples include monomethyl ether monomethacrylate.

The compounding ratio of the compound having a polymerizable unsaturated group that causes a reaction with the coating film-forming resin by active energy rays is 10 by weight.
:9Q to 40:60 is desirable.

In addition to the above essential ingredients, if necessary, photosensitizers, colorants, antifoaming agents, anti-sagging agents, surface conditioners, rust preventives, fillers, solvents, etc. may be added to the extent that they do not adversely affect curability or anticorrosion properties. It may be blended with A photosensitizer is used when ultraviolet rays are used as active energy rays. Specific examples include benzoin, benzoin methyl ether, benzoin ethyl ether, henzoin isopropyl ether, benzoin isobutyl ether, benzyl, benzophenone, 2.2″-jethoxyace[phenone, 2-methylanthraquinone, and 2-ethylanthraquinone. One or more types of such sensitizers can be used, and the amount added is 0.11 to 10% by weight based on the compound having a polymerizable unsaturated group in the coating composition. is preferable.

The top coat composition of the present invention can be obtained by mixing the above-mentioned components by any method used in ordinary coating manufacturing, and the viscosity thereof is 300 to 5000 at 25°C.
cps is preferable. The coating composition thus obtained is applied to a substrate and immediately thereafter cured by irradiation with active energy rays.

A suitable dry film thickness is 5-251. As a coating method, brush coating, spraying, roll coating, curtain flow coating, etc. are used.

A sheet having minute convex surfaces is then pressure-bonded to the top coat formed as described above while the top coat layer resin is in a semi-cured state and maintains fluidity.

The micro-convex sheet is composed of one or more of polyethylene terephthalate, polyvinyl alcohol, and nitrocellulose in terms of releasability from the active energy ray-cured coating film after curing.

The thickness of the sheet is preferably set to 40 to 300 pm. If this thickness is less than 40!1, the sheet and active energy rays will harden when pasting! ! ! Air is likely to be trapped at the interface of the film, and there is a risk of creating a partially uneven pattern. However, even sheets of less than 40 mm are suitable for the principles of the present invention, and the above phenomenon can be sufficiently eliminated by improving equipment such as sheet pasting jigs. On the other hand, if the sheet thickness exceeds 300 mm, the transmittance of active energy rays will deteriorate, making it impractical.

In addition, in order to form a uniform and regular uneven pattern on the top coat surface, the contact surface must be Ra (center line average roughness).
An important requirement is to use a sheet having minute convexities of 0.2 to 50 nm, preferably 0.5 to 10 nm. A sheet with such a convex pattern surface is produced by using a T-die in the sheet extrusion process, and after the sheet is cooled, the desired pattern is formed by applying a desired embossing roll at a temperature near the melting point of the resin and above the glass transition point (Tg). Transfer method or smooth sheet extruded with T-die to its glass transition point (Tg)
It can be produced by using a method of reheating to near the melting point and transferring a pattern using a desired embossing roll.

By using the above-mentioned convex sheet, it is possible to form a concavo-convex coating film with a deep, soft, matte appearance.

In addition, you can also use the
．． It is also effective to use a convex pattern with a constant diagonal spacing of 1 ft by irradiating with a laser at 5 to 500-degree intervals, and when this sheet is used, it exhibits a polarizing matte uneven appearance.

As the pattern of the convex sheet, various convex shapes such as a screen type, a lattice type, a diagonal line type, a vertical line stripe, and a horizontal line stripe can be formed.

To press the sheet, a top coat of active energy ray-curable paint is formed on the base coat, and then the sheet is adhered with a film laminator so that the transfer surface is in contact with the top coat, and the sheet is pressed with an embosser. At this time, it is necessary to set conditions so that air bubbles are not caught between the sheet and the coating film.

Next, active energy rays are irradiated from above the pressed microconvex sheet.

Examples of sources of active energy rays include high-pressure mercury lamps, low-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, ultraviolet generators such as xenon, electron beam accelerators, γ-ray sources such as Co1°, and X-ray generators. In cases where short-time curing is required, it is desirable to use ultraviolet rays or electron beams. The time required for curing varies depending on the type and intensity of active energy rays, but for example,
With a 2KH high-pressure mercury lamp (leaf type) having an input of W, curing can be achieved by irradiating for 1 to 10 seconds on the condensing surface.

After the formed coating film is completely cured in this way, the minute convex sheet is peeled off. The sheet can be peeled off immediately after curing, or it can be applied as a guard film and then peeled off.

(Function) According to the above-described structure of the present invention, the base coat functions effectively to improve the adhesion of the active energy ray-cured paint to the top coat, and also provides pressure bonding of micro-convex sheets, curing of the energy ray-curable paint, Due to the peeling action of the micro-convex sheet, it is possible to develop a soft matte appearance with regular, precise roughness and depth on the entire surface or in the required areas.Moreover, it is possible to develop an anti-corrosive coloring by irradiation with active energy rays. Since the hardening of the hair coat layer can proceed smoothly, it can be used in a wider range of applications than in the prior art.

〔Example〕

Hereinafter, the present invention will be explained based on examples.

Examples 1 to 9, Comparative Examples 1 to 8 A hot-dip galvanized steel sheet was used as the base material, and after surface treatment with zinc phosphate [manufactured by Nippon Paint ■, Granodin Z5-900], the conditions were changed to apply brimer hair coat and A top coat film was formed. The base coat had the composition shown in Table 1. Base coat is Tsurubenz 1
The viscosity was adjusted to 80 to 100 seconds using a 14 force cup using a solvent of 50-butyl cellosolve = 1/1 (weight ratio). Then, while the top coat had fluidity, micro-convex sheets of various properties were pressure-bonded, and the coating layer was completely cured by irradiation with active energy rays using a high-pressure mercury lamp or an electron beam accelerator. After curing, the micro-convex sheet was peeled off to form a concavo-convex pattern on the top coat surface.

The appearance, adhesion, corrosion resistance, workability, etc. of each coating film thus obtained were evaluated, and the results are shown in Table 2 in comparison with the application conditions.

Note that the performance evaluation was based on the following measurement method and evaluation criteria.

(1) Appearance The appearance of the uneven surface was visually evaluated.

(2) Adhesion Measured in accordance with JIS 5400 6.15 and expressed according to the following criteria. (Number of squares remaining after test/number of squares) 100/100...0 50/100 or less...× (3) Corrosion resistance Measured in accordance with JIS 5400 7.8. , displayed according to the following criteria.

Rust surface score: 0%・・・・・・◎ 1-5%・・・・・・0 6-20%・・・Δ 21% or more・・・× (4) Workability JIS 5400 It was displayed.

3R# No IM cracks...○ Measured in accordance with 6.16, following standard 5R...Δ 5R peeling cracks present...× [Effects of the invention] Above As described above, according to the present invention, it is possible to efficiently form a high-grade, matte, finely uneven coating film on the surface of a base material such as metal, plastic, wood, paper, etc.

In particular, when applied to painted steel sheets for construction such as roofs and walls, or painted steel sheets for electrical appliances such as refrigerators and washing machines, it has performance and durability equal to or higher than conventional coatings, and is superior to conventional painted steel sheets. It is possible to give a soft appearance with depth that is hard to see.

Patent applicant: Nippon Paint Co., Ltd. Agent: Patent Attorney Masaya Takahata

Claims (1)

[Claims] 1. Form a base coat with anti-corrosion coloring on the base material surface using methoxylated methylolmelamine as a crosslinking agent, then form a top coat of active energy ray-curable paint, and while the top coat maintains fluidity, polyethylene terephthalate, Formation of a micro-irregular coating film, characterized in that a micro-projection sheet made of one or more of polyvinyl alcohol and nitrocellulose is pressure-bonded, the top coat is cured by irradiation with active energy rays, and then the micro-projection sheet is peeled off. Method.