JPH02209981A - Radiation curing type coating composition for precoated metal and laminated and precoated metal using the same - Google Patents

Abstract

PURPOSE:To obtain the subject composition, containing a urethane-based resin, having a specific molecular weight and (meth)acryloyl groups and containing hydrophilic polar groups and capable of forming transparent films excellent in adhesion and providing a laminated and precoated metal. CONSTITUTION:The objective composition containing a urethane-based resin, having 1000-50000 molecular weight and at least >=1 acryloyl groups and/or methacryloyl groups in one molecular chain and containing 5-2000 equiv./10<6>g hydrophilic polar groups [preferably -COOM1 (M1 is H, alkali metal, tetraalkylammonium or tetraalkylphosphonium), formula I or II, -R3 (R1 to R3 are H, 1-8C alkyl, aryl or aralkyl), formula III, -SO3M1, etc.]. Furthermore, a laminated and precoated metal is formed from the composition as a topcoating layer, an intercoating layer and, as necessary, an undercoating layer.

Description

Detailed Description of the Invention (Field of Industrial Application) The detailed description of the present invention relates to a coating composition that is cured by radiation such as electron beams or ultraviolet rays to form a transparent film with excellent adhesion useful as a pre-coated metal. The present invention relates to a coating composition with excellent pigment dispersibility for forming colored coating films.

Furthermore, the present invention relates to a laminated precoated metal having excellent aesthetic appearance and performance.

(Prior art) Pre-coated metal is a steel plate that has been coated in advance, and by forming and processing it, it can be used for household appliances such as refrigerators and washing machines, office equipment, indoor products such as interior building materials, and roofing materials. Products for outdoor use such as walls and side walls of houses are made. If you use this pre-coated metal,
The demand for pre-coated metal has increased significantly in recent years due to its numerous benefits, including streamlining processes, reducing costs, and eliminating pollution.

The most common manufacturing method for pre-coated metal is to coat a surface-treated metal plate with a thermosetting paint using an appropriate method.
A method of heating and curing is used. Radiation curing methods are being developed as a process that saves resources, saves energy, and produces high-performance films.

However, in radiation curing, internal distortion due to rapid curing and thermal adhesion/wetting cannot be expected, so
It had the disadvantage of poor adhesion to the base.

In addition, in recent years, there has been an increasing demand for dispersibility of pigments, especially in view of the importance of design for indoor utensils and the like.

Conventional radiation-curable resins contain many unsaturated bonds and do not necessarily compatibility with the highly polar pigment surface.As a result, the dispersibility of the pigment is not sufficient (in the coating film formed from these paints, However, various problems arise such as a decrease in gloss, sharpness, color separation, etc., and it is not only impossible to bring out a high level of design, but also poor adhesion, processability,
There was a problem in that the properties such as stain resistance also deteriorated.

In addition, among the pre-coated metals using thermosetting paints that are currently widely used, baking with various pigments is used to form a colored layer on the outermost layer, especially for indoor utensils, because design is important. However, these methods have limitations in performance and aesthetic appearance. For this reason, it is desired to develop a pre-coated metal that overcomes the various performance and aesthetic limitations of the current pre-coated metal.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and its purpose is to provide a radiation-curable coating composition that has excellent glabella adhesion. Another object of the present invention is to provide a radiation-curable coating composition for precoated metal in which pigments are highly dispersed and which exhibits excellent dispersion stability. Furthermore, pre-coated metals obtained using these coating compositions not only exhibit excellent aesthetics, but also have excellent adhesion and
The aim is to exhibit excellent properties in terms of hardness, workability, and stain resistance.

In addition, the present invention provides a laminated precoated metal with excellent aesthetic appearance and performance that cannot be obtained with conventional precoated metals.

(Means for Solving the Problems) The present inventors have proposed a method that has a molecular weight of 1,000 to 50,000, has at least one acryloyl group and/or methacryloyl group in one molecular chain, and has a hydrophilic polar group. 5-2
．． It has been discovered that a resin composition containing a urethane resin containing 0OOeq/106g has excellent adhesion between the eyebrows, and that a coating composition prepared by dispersing a pigment in the urethane resin has excellent pigment dispersibility and dispersion stability. I found it to be excellent.

Furthermore, it has been discovered that a precoated metal obtained by curing this coating composition with radiation has excellent appearance, adhesion, hardness, workability, and stain resistance, leading to the present invention.

That is, the present invention has a molecular weight of 1.000 to 50.000, has at least one acryloyl group and/or methacryloyl group in one molecular chain, and has a hydrophilic polar group of 5 to 2.000 sq/
A radiation-curable pre-coated metal coating composition characterized by containing 106g of urethane resin,
Furthermore, (^) the molecular weight is 1,000 to 50,000, has at least one acryloyl group and/or methacryloyl group in one molecular chain, and has a hydrophilic polar group of 5 to 2,000.
It also includes a radiation-curable coating composition for precoated metal characterized by containing a urethane resin containing 0 eq/106 g and a (B)R agent.

In the present invention, the hydrophilic polar group is R.

(In the formula, H1 represents a hydrogen atom, an alkali metal, a tetraalkylammonium, a tetraalkylphosphonium,
h is a hydrogen atom, an alkali metal atom, a monovalent hydrocarbon group,
Represents an amino group, R1-R3 are hydrogen atoms, carbon number 1-
) representing alkyl, aryl or aralkyl of 8 is preferred.

Furthermore, the urethane resin in the present invention includes (a) a copolymerized polyester polyol, (b) a polyisocyanate compound, (C) a compound having an acryloyl group and/or methacryloyl group and an active hydrogen group in the molecule, and optionally (b) It is a reaction product of a polyol and/or polyamine other than Ia), and (a) and/or (d) preferably contain a hydrophilic polar group.

The above-mentioned copolymerized polyester polyol (a) mainly consists of a dicarboxylic acid component and a glycol component.

Examples of dicarboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and 1,5-naphthalic acid; aromatic oxycarboxylic acids such as p-oxybenzoic acid and p-(hydroxyethoxy)benzoic acid; acids, succinic acid, adipic acid, azelaic acid, sebacic acid,
These include aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, unsaturated aliphatic and alicyclic dicarboxylic acids such as fumaric acid, maleic acid, itaconic acid, hexahydrophthalic acid, and tetrahydrophthalic acid. If necessary, a small amount of tri- and tetracarboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid may be included.

Glycol components include, for example, ethylene glycol, propylene glycol, 1.3-propanediol, 1.
4-butanediol, 1.5-bentanediol, 1.
6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2.
4-) Dimethyl-1,3-bentanediol, 1.4
-Cyclohexane dimetatool, spiroglycol, 1
．． 4-phenylene glycol, ethylene oxide adduct of 1,4-phenylene glycol, bisphenol A
Examples include ethylene oxide adducts and propylene oxide adducts of hydrogenated bisphenol A, ethylene oxide adducts and propylene oxide adducts of hydrogenated bisphenol A, and diols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. If necessary, a small amount of triol and tetraol such as trimethylolethane, trimethylolpropane, glycerin, and pentaerythritol may be included.

In order to obtain a copolymerized polyester polyol from such a dicarboxylic acid component and a glycol component, it is sufficient to synthesize the glycol raw material in excess of the dicarboxylic acid raw material. It is desirable to synthesize it so that it is less than 1G''g.If it is more than 50eq/106g, there will be too many inert terminals in the reaction with the diisocyanate compound when synthesizing the urethane resin described below, and the desired urethane type Resin cannot be obtained and radiation curability decreases.

Other examples of polyester polyols include lactone-based polyester polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone.

As the polyisocyanate compound (b), for example, 2
．． 4-tolylene diisocyanate, 2.6-)lylene diisocyanate, p-phenylene diisocyanate,
diphenylmethane diisocyanate, m-phenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, 3.31-dimethoxy 4.4'-biphenylene diisocyanate, 2,4-naphthalene diisocyanate, 3.3'-dimethyl-4,
4°-biphenylene diisocyanate, 4.4°-diphenylene diisocyanate, anate, 4.4'-diisocyanate-diphenyl ether, 1.5-naphthalene diisocyanate, P-xylylene diisocyanate, m-xylylene diisocyanate, 1.3- Diisocyanate compounds such as diisocyanate methyl cyclohexane, 1,4-diisocyanate methyl cyclohexane, 4.4°-diisocyanate dicyclohexane, 4,4'-diisocyanate dicyclohexylmethane, isophorone diisocyanate, or 7 mol% or less of the total isocyanate groups. .4-) Triisocyanate compounds such as a trimer of lylene diisocyanate and a dimer of hexamethylene diisocyanate can be mentioned.

Compounds (C) having an acryloyl group and/or methacryloyl group and active hydrogen in the molecule include glycol mono(meth)acrylates such as ethylene glycol, diethylene glycol, and hexamethylene glycol, trimethylolpropane, glycerin, and trimethylolethane. Mono(meth)acrylates and di(meth)acrylates of triol compounds such as, mono(meth)acrylates and di(meth)acrylates of polyols with a valence of 4 or more such as pentaerythritol and dipentaerythritol,
Examples include acrylic compounds containing a droxyl group such as tri(meth)acrylate, glycerin monoallyl ether, and glycerin diallyl ether, and acrylic compounds containing an amino group such as (meth)acrylamide and monomethylol(meth)acrylamide. Acrylate and methacrylate were collectively referred to as (meth)acrylate, and acrylamide and methacrylamide were collectively referred to as (meth)acrylamide.

In addition, the polyols and/or polyamines other than the copolymerized polyester polyol (a) that may be used as necessary include glycols, monoethanolamine, N- Examples include amino alcohols such as methylethanolamine, diamines such as ethylene diamine, hexamethylene diamine, isophorone diamine, piperazine, 4,4'-diaminodiphenylmethane, and water.

The urethane resin of the present invention needs to contain a hydrophilic polar group, and the method for containing the hydrophilic polar group is as follows: as the dicarboxylic acid component and/or glycol component of the copolyester polyol (a) Copolymerized polyester polyol (a) when copolymerizing a compound containing a hydrophilic polar group or producing a polyurethane resin
What is necessary is just to copolymerize a polyol and/or polyamine containing a polar group in part or all of the polyol and/or polyamine (d) other than the above.

As a hydrophilic polar group, R.

Oxycarboxylic acids such as propionic acid, N,N-jetanolglycine and hydroxyethyloxybenzoic acid, aminocarboxylic acids such as diaminopropionic acid and diaminobenzoic acid, and derivatives thereof.

R3 (the bond in the formula represents a hydrogen atom, an alkali metal, a tetraalkylammonium, a tetraalkylphosphonium,
Ml represents a hydrogen atom, an alkali metal atom, a monovalent hydrocarbon group, or an amino group, and R1-R3 are hydrogen atoms and have a carbon number of 1
~ represents alkyl, aryl, aralkyl of B).

The polar group-containing compounds used to introduce polar groups into the resin are as follows.

(1) -COOM Polycarboxylic acid, glyceric acid, dimethylol 13 N-methyljetanolamine, 2-methyl-2-dimethylaminomethyl-1,3-propanol, 2, which is the acid component of the above-mentioned polyester polyol (2) -Nitrogen-containing alcohols such as methyl-2-dimethylamino-1,3-propanediol and derivatives thereof.

picolinic acid, dipicolinic acid, aminopyridine, diaminopyridine, hydroxypyridine, dihydroxypyridine, aminohydroxypyridine, pyridine dimetatool,
Pyridine ring-containing compounds and derivatives thereof, such as pyridine propanediol and pyridine ethanol.

(4) -S O2 Polycarboxylic acids and derivatives such as 5-sodium sulfoisophthalate, 5-tetrabutylphosphonium, sulfoisophthalic acid, sodium sulfosuccinate, sodium sulfohydroquinone and alkylene oxide adducts, sodium sulfobisphenol A and Alkylene oxide adducts, etc.

The molecular weight of the present invention is 1,000 to 50,000, at least one acryloyl group and/or methacryloyl group in one molecular chain, and 5 to 2,000 hydrophilic polar groups.
The urethane resin containing 00aq/10''g was added to the copolymerized polyester polyol (a
), polyisocyanate compound (b), compound (e) having an acryloyl group and/or methacryloyl group and active hydrogen in the molecule, and if necessary, polyol and/or polyamine (d) other than (a) in a solvent. , or by reacting in a solvent-free environment.

When the molecular weight is less than t, ooo, the distance between crosslinking points after radiation curing becomes too short, and the processability and adhesion of the resulting precoated metal deteriorate. Also, the molecular weight is so, ooo
If it exceeds the viscosity, the viscosity will already be too high before the pigment is added.
A large amount of solvent, reactive diluent, etc. are required, and when a reactive diluent, which will be described later, is used, the compatibility decreases and image clarity deteriorates.

In addition, the urethane resin of the present invention has an acryloyl group and/or
Alternatively, it is necessary to have at least one methacryloyl group in one molecular chain. If one acryloyl group and/or methacryloyl group is at one end in one molecular chain, there will be a molecule that cannot participate in radiation curing, resulting in poor hardness and stain resistance of the cured coating film.

The polar group concentration in the urethane resin is 5 eq/1G'
If it is less than g, not only will the effect of the present invention regarding adhesion not be sufficiently exhibited, but also the polar group concentration in the urethane resin will be less than 5 eq/10 in coating compositions using pigments.
If the polar group concentration is less than 2.000 eq/10 g, the dispersibility and dispersion stability of the pigment will deteriorate, and the desired effect of the present invention cannot be obtained.If the polar group concentration exceeds 2.000 eq/10 g, the hydrophilicity will deteriorate. If it becomes too high, the water resistance of the coating film will deteriorate.

The pigments used in the coating composition of the present invention are usually
Various inorganic and organic pigments used in the color material industry are used. Inorganic pigments include palite powder, precipitated barium sulfate, heavy calcium carbonate, precipitated calcium carbonate,
Extender pigments such as talc, clay, alumina white, and white carbon, white pigments such as lead white, zinc white, zinc sulfide, lithopone, and titanium dioxide, blue pigments such as ultramarine blue, navy blue, and cobalt blue, chromium oxide, viridian, and chrome green. Green pigments such as yellow lead, molybdate orange, cadmium pigments, titanium yellow, yellow iron oxide, yellow to orange to red pigments such as iron oxide, black pigments such as iron black and carbon black, metals such as aluminum powder, bronze powder, etc. powder pigment,
Examples include anticorrosive pigments such as red lead, zinc oxide powder, lead cyanamide, MIO, zinc chromate, strontium chromate, zinc powder, and cuprous oxide, and antifouling pigments. Further, examples of organic pigments include azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, bat pigments, and dyed lake pigments.

An organic solvent and/or a reactive diluent can be added to the radiation-curable coating composition of the present invention.

Organic solvents are limited to volatile ones, and most or all of them need to be volatilized by heat drying or the like before radiation curing. Usable solvents include acetone and methylethyl!
Esters such as reketone, methylisobutylketonetyl, and ethyl acetate; ethers such as tetrahydrofuran, dioxane, and ethylene glycol monoethyl ether; aromatic hydrocarbons such as benzene, toluene, and xylene; and aliphatic hydrocarbons such as hexane and heptane. The reaction solvent used in the synthesis of the urethane resin A of the present invention, such as alcohols such as methanol, ethanol, and isopropyl alcohol, or mixtures thereof, can also be used as is.

The reactive diluent is incorporated into the crosslinked MR after radiation curing, and is used to adjust the crosslinking density. Specific compounds include 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, and cyclohexyl (meth)acrylate. Acrylate, butoxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, glycidyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, isobornyl (meth)acrylate, ethylene Monomers such as oxide-modified phosphoric acid (meth)acrylate, N-methylvinylpyrrolidone, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, (meth)acryloxyethyl succinate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, etc. Acrylate compound, ethylene glycol di(meth)acrylate, 1
．． 6-hexanethiol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate,
Dicyclopentanyl di(meth)acrylate, bisphenol A di(meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, polyethylene glycol di(meth)acrylate, etc. Acrylate compound, trinotyolpropane tri(meth)
Triacrylate compounds such as acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, propionic acid modified dipentaerythritol Examples include tetraacrylate compounds such as tetra(meth)acrylate, and tetrafunctional or higher functional acrylate compounds such as dipentaerythrimerhexaacrylate.

These reactive diluents may be used as necessary within the scope of the invention. Generally, as the amount added increases, internal strain during curing increases and adhesion with the substrate deteriorates, but since the coating composition of the present invention inherently has good adhesion, its tolerance increases, and various is effectively used to adjust the performance of

In addition to the above-mentioned components, other components can be included in the radiation-curable coating composition of the present invention.

Such ingredients include various additives, catalysts, antioxidants, UV absorbers, antistatic agents, defoamers, plasticizers, desiccants, leveling agents, wetting and penetrating agents, photoinitiators, and stabilizers. and so on. These components may be used as necessary within the scope of the invention.

The radiation-curable coating composition containing the pigment of the present invention has a molecular weight of 1,000 to 50,000, has at least one acryloyl group and/or methacryloyl group in one molecular chain, and has a hydrophilic polar group of 50,000 to 50,000. ~2,000eq/106g
The pigment (B) is obtained by dispersing the pigment (B) in the urethane resin (A) contained in the resin (A) and, if necessary, the other components mentioned above.As the dispersion method, a conventional known method is used.As the dispersion machine, Shikizai Kogyo Co., Ltd. Dispersing machines commonly used in the field, such as sand grind mills, ball mills, roll mills, attritors, day silvers, etc., can be optionally used.

The radiation-curable coating composition of the present invention thus obtained has excellent pigment dispersibility and dispersion stability.

This radiation-curable coating composition is applied to a material used for precoat metal to form a cured coating. Examples of the above-mentioned materials include galvanized steel sheets, cold-rolled steel sheets, electrogalvanized mesh sheets, aluminum plating mesh sheets, steel sheets such as tinplate, tin-free steel, and stainless flIFI, and aluminum sheets. In order to impart paint adhesion and corrosion resistance, these materials are also used after undergoing pretreatments such as crystalline phosphate treatment, amorphous chromemate treatment, and composite oxide film treatment.

The coating structure formed on the above material using the present composition may be a single layer structure made of one type of composition, or a multilayer structure of two or more layers made of different compositions.
Further, the present composition may be applied directly onto the material, or a primer may be applied onto the material and the present composition may be applied thereon.

When painting using this composition, various conventionally known methods are possible. Examples include spray roller coat, curtain flow coat, and knife coat.

The coating film is cured by irradiation with radiation.

Radiation used in the present invention includes ultraviolet rays, electron beams, r-rays, neutron beams, and the like. When using ultraviolet radiation, it is desirable to add a photoinitiator to the radiation-curable coating composition.

Photoinitiators include acetophenone, benzophenone,
benzoin ethyl ether, benzyl methyl ketal,
Benzyl ethyl ketal, benzoin isobutyl ketone, hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2,2-jethoxyacetophenone, Michler's ketone, 2-hydroxy-2-methylpropiophenone, benzyl, diethylthioxanthone , 2-chlorothioxanthone, benzoylethoxyphosphine oxide, 1-)limethylbenzoyldiphenylphosphine oxide, and the like can be used.

Also, if necessary, photosensitizers such as n-butylamine, dibutylamine triethylamine, etc. may be used.

The scanning method or curtain beam method is used as the electron beam irradiation machine, and the absorbed dose is 1 to 20 Mra.
d Preferably 2 to 15 Mrad, the absorbed dose is IM
If the curing reaction is less than 20 Mrad, the curing reaction is insufficient.
Exceeding this is not preferable because the energy efficiency used for curing may decrease or excessive crosslinking may proceed.

The laminated precoated metal of the present invention includes (1) a top coat layer (2) an intermediate coat layer (3) using the above-mentioned radiation-curable coating composition.
It consists of an undercoat layer if necessary.

The resin used in the intermediate coating layer is appropriately selected from conventionally known thermosetting resins and radiation curable resins. Examples of thermosetting resins include amine alkyd, oil-free polyester, vinyl-modified alkyd, solution type vinyl,
Examples include organosol, plastisol, epoxy, epoxy ester, baking type acrylic, silicone alkyd, silicone acrylic, silicone polyester, polyvinyl fluoride, polyvinylidene fluoride, and the like.

Examples of radiation-curable resins include polyester acrylate, epoxy acrylate, polyurethane acrylate, polyether acrylate, oligoacrylate, alkyd acrylate, and polyol acrylate.

The radiation-curable coating composition of the present invention may also be used.

The intermediate coating layer consists of the above resin and, if necessary, pigments and various additives.

As the pigment, those used in the various color material industries mentioned above are used. These blending ratios and dispersion methods may be conventionally known amounts and methods.

The undercoat layer, which is used as necessary, is mainly used to impart rust prevention properties. There are no particular restrictions on the resin as long as it achieves this purpose, but examples include acrylic resins, polyester resins with excellent processability, and epoxy resins with excellent rust prevention and chemical resistance. can give.

The laminated precoat metal of the present invention is produced by forming an undercoat layer, if necessary, on the material used for the precoat and metal, and then applying, drying, and curing the above colored intermediate coat paint by a conventionally known method to form a colored intermediate coat layer. to form. After that, the radiation-curable coating composition of the present invention may be applied on the colored intermediate coating layer, thereby providing excellent aesthetic appearance, hardness, workability, and stain resistance that cannot be obtained with conventional precoated metals. Pre-coated metal is obtained. The adhesion between the top coat and intermediate coat is also very good.

(Function) The radiation-curable resin composition and coating composition of the present invention can improve the wettability of the interface due to the hydrophilic polar groups contained in the urethane resin, so that it is possible to obtain one with excellent glabellar adhesion. Can be done. Further, the pigment contained therein has excellent dispersibility and dispersion stability.

Furthermore, it has radiation curability due to the acryloyl group and/or methacryloyl group. Therefore, the pre-coated metal produced using this radiation-curable coating composition not only has excellent adhesion between the eyebrows, but also reduces the coloring power and causes color separation in the coating when pigments are used. Therefore, the precoated metal obtained has an appearance with excellent gloss and sharpness. Furthermore, it is possible to obtain a material that fully satisfies other performance requirements for precoated metal, such as hardness, workability, and stain resistance.

Furthermore, a new type of laminated precoat metal can be obtained which has the above-mentioned excellent properties not found in conventional precoat metals and is also excellent in aesthetics and design.

(Example) Examples of the present invention will be described below. In the examples, parts simply indicate parts by weight.

(]) Production example of copolymerized polyester polyol In an autoclave equipped with a thermometer and a stirrer, 256 parts of dimethyl terephthalate, 256 parts of dimethyl isophthalate, 409 parts of ethylene glycote, 458 parts of neopentyl glycol, and 0.68 parts of trabutoxy titanate. 292 parts of adipic acid and 65 parts of 5-sodium sulfoisophthalic acid were added and heated at 150 to 230°C for 120 minutes to carry out a transesterification reaction.
The reaction system was further reacted at 220 to 230°C for 1 hour, then heated to 250°C in 30 minutes, the pressure of the system was gradually reduced to 10 m It g after 45 minutes, and the reaction was continued for another 60 minutes. continued. The molecular weight of the obtained copolymerized polyester polyol A was 2000, and the acid value was 10 eq/10.
”g, and the sulfonic acid metal base in the resin is 200 eq.
/io'g.

Copolymerized polyester polyols B and C obtained by a similar manufacturing method are shown in Table 1.

The amounts of the sulfonate metal base and the phosphonate metal base were determined by measuring the sulfur concentration and phosphorus concentration, respectively, in the copolymerized polyester polyol.

Table 1 (2) Production example of urethane resin In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser,
Copolymerized polyester polyol 510 obtained in (1)
0 parts and 100 parts of cyclohexanone were charged, and the copolymerized polyester polyol was melted. Furthermore, 2.4-
) Add 19 parts of lylene diisocyanate and react at 70 to 80 °C for 3 hours to obtain an isocyanate-terminated prepolymer. Cool the reaction vessel to 60 °C, add 30 parts of pentaerythritol triacrylate, and react at 70 to 80 °C. ℃
The mixture was reacted for 6 hours to obtain a solution of urethane resin A having a solid content concentration of 60% by weight. The molecular weight of urethane resin A is 29
00, and the sulfonic acid metal base in the resin is 140 eq.
/lo'g.

Copolymerized polyester polyols A and B by the same method
, C to obtain urethane resin B-H.

The obtained urethane resins are shown in Table 2.

Below is a blank space (3) Example of manufacturing a paint Add 6 parts of titanium oxide to 100 parts of the solution of the above urethane resin A.
0 parts and 50 parts of pentaerythritol tetraacrylate
A white paint composition A was prepared using 10 parts of Tsurupetz 915040 and a paint conditioner.

Urethane resin B-
A white paint composition B-H was obtained from H.

(4) Example 1, Comparative Example 1 The white paint composition shown in Table 3 was applied on a 0.6 m thick electrogalvanized net plate coated with a polyester primer to a thickness of 3 μm and heat cured (melamine cured). A-H was coated using a bar coater so that the thickness after drying was 15 μm. After drying in a hot air dryer at 140°C for 2 minutes,
Accelerating voltage 165KV, @current 5m^, absorbed dose 10Mr
Ad electron beam irradiation was performed to cure the coating film to obtain a pre-coated metal.

This operation was performed on the above-mentioned white coating compositions A-H immediately after production and on those left standing for 24 hours, and the performance was evaluated for each.

An overview of the performance evaluation is shown below.

■ Variable angle gloss meter GLO5S METER made by Glossy Tokyo Heavy Color ■
MO mouth 11! Using L TC-1080, 60° and 2
Specular reflectance at 0° was measured.

■ Portable sharpness gloss meter manufactured by Japan Color Research Institute <PGD
Gd by the appearance of the image of the test pattern using type IV
The value was determined. The average value of 5 repeated measurements was taken as the measured value. The larger the value, the better the image clarity.

0 Pencil Hardness Tested using Mitsubishi Pencil Uni, and expressed as the hardness one rank below the lowest hardness that causes scratches.

＠ Bending the pre-coated metal 180° using a paint film bending tester manufactured by Tenyu Equipment. At this time, the minimum diameter of the mandrel without causing cracks or peeling on the painted surface was indicated.

0 Base grain adhesion Using Tenyu Kijitsu ■'s base grain test ruler, create 100 base grains of 1 × 1 square on the coating film with a cutter knife, apply Sellotape N11405 manufactured by Nichiban ■, and peel it off. I did it. At this time, the number of base lines in which the coating film adhered without peeling was evaluated.

Φ Stain Resistance A line was drawn on the painted surface using three colored marker inks of red, blue and black, and after being left for 24 hours, it was wiped off with gauze soaked in ethanol and the trace of the line was evaluated.

O: No marks left Δ: Slight marks left ×: Marks clearly left The performance evaluation results obtained in this way are shown in Tables 3 and 4.
Shown in the table.

Example 2, Comparative Example 2 50 parts of pentaerythritol tetraacrylate was further added to the white paints A, G, and H2CO parts used in Example 1 to produce white paints A', G', and H'. Example 1 except that a 0.6-thick electrolytic galvanized steel plate coated with epoxy primer to a thickness of 3μ and heat-cured was used.
A precoated metal was produced in the same manner as in Comparative Example 1, and its performance was evaluated. The results are shown in Tables 5 and 6.

Below are margins Example 3, Comparative Example 3 A cyclohexanone solution of the urethane resins A to H shown in Table 2 was applied to a galvanized steel plate with a thickness of 0.5 mm1 so that the thickness after drying was lOμ-. .

After drying in a hot air dryer at 140°C for 2 minutes to remove the solvent, the accelerating voltage was 165 V, the current was 5-^, and the absorbed dose was 10 M.
rad electron beam irradiation was performed. The resulting cured coating film was evaluated for pencil hardness, workability, and adhesion to the substrate. The results are shown in Table 7, and the evaluation was performed using the following method.

Below is a margin Table 7 Example 4 100 parts of Vylon RV600 (copolymerized polyester resin manufactured by Toyobo Co., Ltd.), 25 parts of melamine resin, and 100 parts of titanium oxide were placed on a galvanized iron plate on which a thermosetting epoxy primer was formed with a thickness of 5μ steel. A white paint consisting of 0.25 parts of P-toluenesulfonic acid solution as a catalyst, 0.5 parts of Polyflow S (manufactured by Kyoeisha Yushi ■) as a surface smoothing agent, cyclohexanone as a solvent, and 15,150 parts of Tsurupera Acupoint was applied with a bar coater and cured by baking. and the thickness is 20tI11
A white intermediate coating layer was formed. The performance of this pre-coated metal was good, with a pencil hardness of H1 and workability of 2 φ, and an adhesion to the substrate of 100/100.
degree) 85, image sharpness 0.20, stain resistance x, and aesthetic appearance were not satisfactory.

Using the white paint A used in the example, a white top coat layer was formed on the white intermediate coat layer in the same manner as in Example 2. The performance of this laminated pre-coated mesh board has a pencil hardness of 2H1
It has good workability with 2mm diameter, adhesion to the substrate of 100/100, gloss (60") 95, and sharpness 0.70.
It also had stain resistance O and excellent aesthetic appearance.

(Effects of the Invention) The radiation-curable coating composition of the present invention has excellent pigment dispersibility, and therefore exhibits an excellent aesthetic appearance when used as a pre-coated metal. Excellent in sex.

Furthermore, this coating composition shows excellent dispersion stability of the pigment, and the obtained pre-coated metal coating film has excellent properties such as no decrease in gloss, decrease in image clarity, decrease in tinting power, or color separation. It is.

In addition, it is possible to obtain a product with excellent glabella adhesion, so it can be usefully used for single-layer or laminated pre-coated steel sheets.In addition to the above properties, various designs can be created by changing the presence or absence of pigments and the type of pigment. It is possible to obtain coated laminated pre-coated steel sheets.

Patent Applicant: Toyobo Co., Ltd. Procedural Amendment (Method) Description of the Case 1999 Patent Application No. 180453 Name of the Invention: Radiation-curable coating composition for pre-coated metal and correction of laminated pre-coated metal using the same. Relationship between patent applicant 2-2-8-5 Dojimahama, Kita-ku, Osaka City, ``Title of the invention column'' of the specification subject to amendment a Contents of the amendment (1) The ``title of the invention'' in the description is as follows: Correct.

"Radiation-curable coating composition for pre-coated metal and laminated pre-coated metal using the same" September 14, 1999

Claims (1)

[Scope of Claims] 1. A molecular weight of 1,000 to 50,000, having at least one acryloyl group and/or methacryloyl group in one molecular chain, and 5 to 2,000 eq of hydrophilic polar groups.
1. A radiation-curable coating composition for pre-coated metal, characterized in that it contains a urethane resin containing: /10^6g. 2. A laminated precoated metal comprising (1) a top coat layer using the radiation-curable coating composition according to claim 1, (2) an intermediate coat layer, and optionally (3) an undercoat layer.