JP7821226B2 - Film forming method and laminate - Google Patents

Description

The present invention relates to a novel coating formation method.

Conventionally, the surfaces of buildings, civil engineering structures, and the like have sometimes been coated with urethane resin coating materials containing plasticizers ("plasticizer-containing coating materials"). Such plasticizer-containing coating materials contain a polyol component, a polyisocyanate component, and a plasticizer. Furthermore, a coating material may be laminated onto the surface of this plasticizer-containing coating material for protection, design, etc. However, plasticizers can migrate into the coating material over time, and contaminants may adhere to the coating material surface, resulting in a decrease in aesthetics and adhesion.

In response to this, for example, Patent Document 1 proposes a non-migratory polymer plasticizer, which is described as not migrating to the surface due to its high molecular weight.

Japanese Patent Application Laid-Open No. 2001-226442

However, currently, low-molecular-weight plasticizers are commonly used in plasticizer-containing coating materials, and there is a need to develop a coating formation method that can be applied to such plasticizer-containing coating materials.

To solve these problems, the inventors discovered that by forming a coating by applying a second coating material containing a specific polyol component (A) to the surface of a first coating material containing a polyol component, a polyisocyanate component, and a plasticizer, it is possible to form a coating that is excellent at preventing plasticizer migration and has excellent adhesion, leading to the completion of the present invention.

That is, the present invention has the following features.
1. A coating formation method in which a first coating material is applied and dried, and then a second coating material is applied to the surface of the coating (first coating),
the first coating material contains a plasticizer,
The first coating material and the second coating material each contain a polyol component (A) and a polyisocyanate component (B) as resin components,
the second coating material contains a polyol component (A2) having a hydroxyl value greater than that of the polyol component (A1) of the first coating material,
The method for forming a coating film, wherein the second coating material contains a polyether polyol (Ax2) and an acrylic polyol (Ay2) as the polyol component (A2).
2. The first coating material contains a polyether polyol (Ax1) as the polyol component (A),
1. The method for forming a coating according to 1., wherein the second coating material contains a polyether polyol (Ax2) having a hydroxyl value greater than that of the polyether polyol (Ax1) of the first coating material.
3. The method for forming a coating according to 1., wherein the polyether polyol (Ax2) contains a polyether polyol having a hydroxyl value of 50 mg KOH/g or more.
4. The method for forming a coating according to 1., wherein the weight ratio (solid content) of the polyether polyol (Ax2) to the acrylic polyol (Ay2) is 90:10 to 10:90.
5. The coating forming method according to 1., further characterized in that a topcoat material is applied.
6. A laminate having a second coating formed from a second coating material on a surface of a first coating formed from a first coating material,
the first coating material contains a plasticizer,
The first coating material and the second coating material each contain a polyol component (A) and a polyisocyanate component (B) as resin components,
the second coating material contains a polyol component (A2) having a hydroxyl value greater than that of the polyol component (A1) of the first coating material,
The second coating material is a laminate comprising a polyether polyol (Ax2) and an acrylic polyol (Ay2) as the polyol component (A2).

The present invention relates to a coating formation method for applying a first coating material and a second coating material, wherein the first coating material contains a plasticizer, the first coating material and the second coating material contain polyol component (A) and polyisocyanate component (B) as resin components, and the second coating material contains polyol component (A2) having a higher hydroxyl value than the polyol component (A1) of the first coating material, thereby enabling the formation of a coating that is excellent in preventing plasticizer migration and has excellent adhesion.

The present invention will be described in detail below based on its embodiments.

The present invention relates to a coating formation method in which a first coating material and a second coating material are applied in that order. Both the first coating material and the second coating material in the present invention contain a polyol component (A) and a polyisocyanate component (B) as resin components. The second coating material contains a polyol component (A2) that has a higher hydroxyl value than the polyol component (A1) of the first coating material. We will first explain the common features of these first and second coating materials (hereinafter, both will be collectively referred to simply as "coating materials").

The coating material of the present invention contains a polyol component (A) and a polyisocyanate component (B), which react to form a coating.

Examples of the polyol component (A) (hereinafter also referred to as "component (A)") of the present invention include polyether polyols, polyester polyols, castor oil, castor oil-modified polyols, epoxy-modified polyols, silicone-modified polyols, fluorine-modified polyols, acrylic polyols, polycarbonate polyols, polylactone polyols, polybutadiene polyols, and polypentadiene polyols. The coating material of the present invention preferably contains one or more polyether polyols and acrylic polyols. These polyols are preferably liquid at 20°C and can be used in forms such as solvent-soluble and nonaqueous dispersion (NAD) types.

Polyether polyol (Ax) (hereinafter also referred to as "component (Ax)") is obtained by addition polymerization of polyhydric alcohols such as trimethylolpropane, glycerin, hexanetriol, pentaerythritol derivatives, sorbitol, and neopentyl glycol with alkylene oxides such as ethylene oxide and propylene oxide. In the present invention, polymers obtained by addition polymerization of the above polyhydric alcohols with ethylene oxide and/or propylene oxide are preferred, and those with ethylene oxide and/or propylene oxide attached to the terminals can also be used. Furthermore, in the present invention, it is preferable that component (Ax) contains a polyether polyol having three or more functional groups (hydroxyl groups) containing active hydrogen atoms (functionality of three or more). In this case, the crosslinking density of the formed coating can be increased, allowing the effects of the present invention to be fully exerted.

The acrylic polyol (Ay) (hereinafter also referred to as "component (Ay)") contains as constituent components an alkyl (meth)acrylate ester, a hydroxyl group-containing monomer, and, if necessary, other monomers, and a polymer of these can be used. An alkyl (meth)acrylate ester is a compound having a (meth)acryloyl group and an alkyl group. In the present invention, alkyl acrylate ester and alkyl methacrylate ester are collectively referred to as alkyl (meth)acrylate ester. A monomer is a general term for a compound having a polymerizable unsaturated double bond.

Examples of such (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, t-pentyl (meth)acrylate, 1-ethylpropyl (meth)acrylate, 2-methylbutyl (meth)acrylate, and (meth) Examples include 3-methylbutyl acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, 2-methylpentyl (meth)acrylate, 4-methylpentyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate, and n-lauryl (meth)acrylate. These can be used alone or in combination.

Examples of the hydroxyl group-containing monomer include (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. These can be used alone or in combination of two or more.

Examples of the other monomers include aromatic monomers, carboxyl group-containing monomers, amino group-containing monomers, pyridine-based monomers, nitrile group-containing monomers, amide group-containing monomers, epoxy group-containing monomers, carbonyl group-containing monomers, alkoxysilyl group-containing monomers, fluorine-containing monomers, ultraviolet absorbing group-containing monomers, and photostable group-containing monomers. These can be used alone or in combination of two or more.

Furthermore, in the present invention, a polyester-containing acrylic polyol containing an acrylic polyol and a polyester can also be used as component (Ay). The polyester-containing acrylic polyol can be obtained, for example, by reacting a polyester resin having a polymerizable unsaturated group with a (meth)acrylic acid alkyl ester, a hydroxyl group-containing monomer, and, if necessary, other polymerizable monomers.

Polyester resins having polymerizable unsaturated groups can be obtained by using a polybasic acid and/or polyhydric alcohol that has a polymerizable unsaturated group when a polyester resin is obtained by condensation reacting a polybasic acid with a polyhydric alcohol. Polyester resins having polymerizable unsaturated groups can also be obtained by reacting a polyester resin with a monomer that can react with the hydroxyl or carboxyl groups in the polyester resin, specifically maleic acid, (meth)acrylic acid, glycidyl (meth)acrylate, etc.

The hydroxyl value of the above-mentioned component (A) is preferably 1 to 1,000 mg KOH/g (more preferably 3 to 900 mg KOH/g). By including such a component (A), the effects of the present invention can be fully achieved. Note that the hydroxyl value referred to here is the value expressed in mg of potassium hydroxide equivalent to the moles of hydroxyl groups contained in 1 g of solids (KOH mg/g). Furthermore, in the present invention, "α to β" is synonymous with "α or more and β or less."

The polyisocyanate component (B) (hereinafter also referred to as "component (B)") in the coating material of the present invention is a component that undergoes a curing reaction with the above-mentioned component (A). In the present invention, this curing reaction provides sufficient effects in terms of adhesion, prevention of plasticizer migration, etc.

Examples of component (B) include toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (pure-MDI), polymeric MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), hydrogenated XDI, hydrogenated MDI, etc., as well as derivatives thereof that have been allophanated, biurated, dimerized (uretidione), trimerized (isocyanurated), adducted, or carbodiimided; and blocked isocyanates obtained by blocking these with alcohols, phenols, ε-caprolactam, oximes, active methylene compounds, etc., and one or more selected from these can be used.

In the present invention, it is preferable that component (B) contains hexamethylene diisocyanate (HMDI) and/or its derivatives (hereinafter also referred to as "HMDIs"). The content of the HMDIs is preferably 90% by weight or more (more preferably 95% by weight or more) of the total amount (solid content) of component (B). A suitable embodiment is also one in which component (B) consists solely of HMDIs. Furthermore, a biuret derivative is suitable as the derivative. In such a case, the formed coating has excellent curing properties and can improve adhesion, plasticizer migration prevention, etc.

The NCO content of component (B) is preferably 10 to 35% by weight (more preferably 13 to 32% by weight, and even more preferably 15 to 30% by weight). In such cases, adhesion can be improved. Note that the NCO content refers to the weight percentage of NCO contained in component (B).

Component (A) and component (B) are mixed in such a ratio that the NCO/OH equivalent ratio of component (A) to component (B) is preferably 0.6 to 3.5 (more preferably 1 to 3.0, and even more preferably 1.1 to 2.5). In such cases, the resulting composition exhibits excellent curability and the full effects of the present invention.

In the present invention, a curing catalyst that promotes the reaction between components (A) and (B) can be used in combination. A curing catalyst is a substance that promotes the reaction and curing of isocyanate groups. Examples of curing catalysts include amine catalysts, organometallic catalysts, and inorganic catalysts. Examples of amine catalysts include ethylenediamine, triethylenediamine, triethylamine, ethanolamine, diethanolamine, and hexamethylenediamine, or their derivatives or mixtures with solvents. Examples of organometallic catalysts include organometallic compounds such as dibutyltin dilaurate and dibutyltin diacetate; and organometallic salts such as potassium acetate, zinc stearate, calcium stearate, lead stearate, aluminum stearate, and tin octoate. Examples of inorganic catalysts include tin chloride. These can be used alone or in combination, or mixed with a solvent. In the present invention, the inclusion of an organometallic catalyst is particularly preferred. In this case, curing is accelerated and sufficient effects are achieved in terms of adhesion, prevention of plasticizer migration, etc. from the early stages of film formation.

In addition to the components mentioned above, the coating material of the present invention can also contain various other components, as long as they do not significantly impair the effects of the present invention. Examples of such components include color pigments, extender pigments, flame retardants, foaming agents, carbonizing agents, thickeners, plasticizers, preservatives, antifungal agents, anti-algae agents, defoaming agents, leveling agents, pigment dispersants, anti-skinning agents, driers, matting agents, UV absorbers, light stabilizers, antioxidants, anti-fouling agents, and catalysts.

In the present invention, a coating is formed by applying (painting) such coating materials (first coating material and second coating material) to a substrate. In the present invention, it is desirable to apply the first coating material to the substrate, allow the coating (first coating) to dry, and then apply the second coating material. The substrate constitutes the surface of a building, civil engineering structure, etc. Specifically, it can be applied to various substrates such as walls, pillars, floors, beams, roofs, stairs, ceilings, and doors. Applicable substrates include, for example, concrete, mortar, siding board, extruded board, gypsum board, perlite board, brick, plastic, wood, metal, steel frame (steel), glass, and porcelain tile. These substrates may already have a coating formed on their surface, may have undergone some kind of surface treatment (rust prevention treatment, flame retardant treatment, etc.), or may have wallpaper applied.

The second coating material can be applied directly to the first coating, or via some other layer (e.g., a primer layer, an intermediate coating layer, etc.). In the present invention, it is preferable to apply it directly to the first coating. This allows for sufficient effects in terms of preventing plasticizer migration and adhesion. Such a second coating material is effective as a coating material for preventing plasticizer migration.

Next, the characteristics of the first coating material and the second coating material will be described.
The first and second coating materials each contain the polyol component (A) as a resin component. Furthermore, the present invention is characterized in that the second coating material contains a polyol (A2) having a higher hydroxyl value than the polyol component (A1) of the first coating material. That is, the first coating material contains the polyol component (A1) having a relatively low hydroxyl value, and the second coating material contains the polyol component (A2) having a relatively high hydroxyl value. By using the first and second coating materials of this type in the present invention, excellent plasticizer migration prevention properties and sufficient adhesion can be achieved.

In the present invention, the difference in hydroxyl value between the polyol component (A1) and the polyol component (A2) is preferably 5 mgKOH/g or more (more preferably 10 mgKOH/g or more, even more preferably 50 mgKOH/g or more, particularly preferably 100 mgKOH/g or more, and most preferably 150 mgKOH/g or more). In such cases, excellent plasticizer migration prevention properties can be exhibited. Specifically, the hydroxyl value of the polyol component (A1) is preferably 1 to 200 mgKOH/g (more preferably 3 to 150 mgKOH/g). Furthermore, the hydroxyl value of the polyol component (A2) is preferably 30 to 1000 mgKOH/g (more preferably 35 to 900 mgKOH/g). If either or both of the first and second coating materials contain multiple polyol components, it is sufficient that at least one polyol component (A1) in the first coating material and at least one polyol component (A2) in the second coating material satisfy the above conditions.

Furthermore, the first and second coating materials preferably contain a polyether polyol (Ax) as the polyol component (A), and the second coating material preferably contains a polyether polyol (Ax2) having a higher hydroxyl value than the polyether polyol (Ax1) of the first coating material. Specifically, the hydroxyl value of the polyether polyol component (Ax1) contained in the first coating material is preferably 1 to 200 mgKOH/g (more preferably 3 to 180 mgKOH/g, even more preferably 5 to 150 mgKOH/g, particularly preferably 8 to 100 mgKOH/g, and most preferably 10 to 35 mgKOH/g). The hydroxyl value of the polyether polyol (Ax2) contained in the second coating material is preferably 50 mgKOH/g or higher (more preferably 100 mgKOH/g or higher, even more preferably 150 mgKOH/g or higher, particularly preferably 200 mgKOH/g or higher, and most preferably 250 mgKOH/g or higher). There is no particular upper limit, but it is preferably 1000 mg KOH/g or less (more preferably 800 mg KOH/g or less). In such cases, the effects of the present invention can be further enhanced.

Furthermore, it is preferable that the second coating material contains a polyether polyol (Ax2) having a smaller molecular weight than the polyether polyol (Ax1) of the first coating material. That is, it is preferable that the first coating material contains a polyether polyol (Ax1) having a relatively large molecular weight, and the second coating material contains a polyether polyol (Ax2) having a relatively small molecular weight. This can further improve plasticizer migration prevention and adhesion.

The difference in molecular weight between the polyether polyol (Ax1) and the polyether polyol (Ax2) is preferably 2,000 or more (more preferably 3,000 or more, even more preferably 4,000 or more, particularly preferably 6,000 or more, and most preferably 6,500 or more). In such cases, excellent plasticizer migration prevention properties can be achieved. Specifically, the molecular weight of polyether polyol (Ax1) is preferably 1,000 or more (more preferably 3,000 or more, even more preferably 5,000 or more, particularly preferably 6,000 or more, and most preferably 6,500 or more), with the upper limit being preferably 18,000 or less (more preferably 15,000 or less, and even more preferably 12,000 or less). The molecular weight of polyether polyol (Ax2) is preferably 4,000 or less (more preferably 2,000 or less, even more preferably 1,000 or less, particularly preferably 900 or less, and most preferably 600 or less), with the lower limit being preferably 50 or more (more preferably 100 or more, and even more preferably 150 or more). Use of such an (Ax2) component can enhance plasticizer migration prevention. Note that the molecular weight of the polyol component in the present invention is the number average molecular weight (Mn), which is the so-called polystyrene-equivalent molecular weight determined by gel permeation chromatography using a polystyrene polymer as a reference.

Note that when either or both of the first coating material and the second coating material contain multiple polyether polyols (Ax), it is sufficient that at least one polyether polyol component (Ax1) of the first coating material and at least one polyether polyol component (Ax2) of the second coating material satisfy the above conditions. It is more preferable that all polyether polyols (Ax2) of the second coating material satisfy the above conditions for all polyether polyols (Ax1) of the first coating material.

In the first coating material, the solid content of the polyether polyol (Ax1) in the solid content of the component (A1) is preferably 50% by weight or more (more preferably 80% by weight or more, and even more preferably 90% by weight or more). There is no particular upper limit, and the component (A1) may consist solely of the polyether polyol (Ax1). In such cases, the effects of the present invention can be fully achieved.

Meanwhile, the second coating material preferably further contains an acrylic polyol (Ay2) as the polyol component (A2). In this case, the hydroxyl value of the acrylic polyol (Ay2) is preferably 1 to 200 KOH mg/g (more preferably 3 to 100 KOH mg/g, and even more preferably 5 to 80 KOH mg/g). A hydroxyl value of the acrylic polyol (Ay2) within this range provides excellent plasticizer migration prevention and is advantageous in terms of improved adhesion. Furthermore, the weight ratio (solids content) of the polyether polyol (Ax2) to the acrylic polyol (Ay2) is preferably 90:10 to 10:90 (more preferably 80:20 to 20:80, and even more preferably 70:30 to 50:50). In such a case, excellent plasticizer migration prevention and improved adhesion are advantageous.

Furthermore, in the present invention, the solid content (total) of the polyether polyol (Ax2) and the acrylic polyol (Ay2) in the solid content of the component (A2) is preferably 50% by weight or more (more preferably 80% by weight or more, and even more preferably 90% by weight or more). There is no particular upper limit, and the component (A2) may consist only of the polyether polyol (Ax2) and the acrylic polyol (Ay2). In such cases, the effects of the present invention can be fully exerted.

The first coating material of the present invention contains a plasticizer as an essential component in addition to the resin component. Such a first coating material is not particularly limited as long as it is a material containing a plasticizer in the resin component, but examples include coating materials, sheets, sealants, plastisols, etc., which may have various functionalities (e.g., waterproofing, flame retardancy, heat resistance, etc.).

Plasticizers are not particularly limited, but examples include phthalate ester compounds such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, dihexyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, and butyl benzyl phthalate; diethyl adipate, dibutyl adipate, diisobutyl adipate, dihexyl adipate, di-2-ethylhexyl adipate, dioctyl adipate, diisononyl adipate, diisodecyl adipate, and Aliphatic dibasic acid ester compounds such as bis(butyl diglycol) dipicate, diethyl sebacate, dibutyl sebacate, dihexyl sebacate, and di-2-ethylhexyl sebacate; adipic acid polyester compounds such as 1,3-butylene glycol adipic acid polyester and 1,2-propylene glycol adipic acid polyester; maleic acid ester compounds such as dimethyl maleate, diethyl maleate, dibutyl maleate, dihexyl maleate, di-2-ethylhexyl maleate, diisononyl maleate, and diisodecyl maleate;

Phosphate ester compounds such as triethyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, and 2-ethylhexyl diphenyl phosphate; trimellitic acid ester compounds such as tris-2-ethylhexyl trimellitate; ricinoleic acid ester compounds such as methyl acetyl risinoleate; epoxy ester compounds such as di-2-ethylhexyl epoxyhexahydrophthalate, diepoxystearyl epoxyhexahydrophthalate, epoxidized fatty acid butyl, epoxidized fatty acid 2-ethylhexyl, epoxidized soybean oil, and epoxidized linseed oil; benzoic acid ester compounds such as benzoic acid glycol ester; chlorinated paraffins; aromatic hydrocarbon compounds such as 1-phenyl-1-xylylethane and 1-phenyl-1-ethylphenylethane; lactones such as γ-butyrolactone; and mixtures of petroleum resins (polymers of aromatic hydrocarbon fractions having 8 to 10 carbon atoms) and styrylxylene. These may contain one or more types.

In the present invention, it is preferable that the first coating material contains one or more compounds selected from the group consisting of phthalate ester compounds, aliphatic dibasic acid ester compounds, phosphate ester compounds, and chlorinated paraffins. In this case, the effects of the present invention can be fully achieved. Furthermore, in the present invention, the effects of the present invention can be fully achieved even when the first coating material contains a relatively low-molecular-weight plasticizer with a molecular weight of 1,000 or less (preferably 100 to 800). The molecular weight of the plasticizer is a value calculated from the molecular formula.

The content of plasticizer in the first coating material is preferably 5 to 200 parts by weight (more preferably 10 to 150 parts by weight) per 100 parts by weight of the total solid content of the polyol component (A1) and the polyisocyanate component (B1) (hereinafter also referred to as the "resin component (solid content)"). Even when a relatively large amount of plasticizer is included, the coating formation method of the present invention can still achieve sufficient effects in terms of preventing plasticizer migration and adhesion.

Furthermore, the first coating material may contain functional powders to impart various functions. Examples of functional powders that can be used include powders that provide desired functions, such as heat insulation powders, heat resistance powders, UV blocking powders, and infrared blocking powders. By including such functional powders, the coating can be given desired performance. Examples of such functional powders include heat insulation powders, heat resistance powders, and UV blocking powders. These can be used alone or in combination of two or more types.

The first coating material of the present invention preferably contains a heat-resistance-imparting powder as the functionality-imparting powder. Such a first coating material is suitable as an intumescent fire-resistant coating material to be applied to the surface coating of structures such as buildings and civil engineering structures. The heat-resistance-imparting powder may be any powder that exhibits at least one of the following effects at high temperatures: dehydration and cooling effect, non-flammable gas generation effect, binder carbonization promotion effect, carbonized insulation layer formation effect, and the like, and has the effect of suppressing combustion. Examples of such powders include foaming agents, carbonizing agents, and flame retardants.

Specific examples of foaming agents include melamine and its derivatives, dicyandiamide and its derivatives, azobistetrazole and its derivatives, azodicarbonamide, urea, and thiourea. These can be used alone or in combination of two or more. The content of the foaming agent is preferably 10 to 200 parts by weight (more preferably 20 to 150 parts by weight) per 100 parts by weight of the resin component (solid content). The foaming agent of the present invention imparts a foaming action to the coating when the temperature rises during a fire, etc.; specifically, it imparts a foaming action when the temperature of the coating surface preferably reaches 200°C or higher.

Examples of carbonizing agents include pentaerythritol, dipentaerythritol, trimethylolpropane, starch, and casein. These can be used alone or in combination of two or more. In the present invention, pentaerythritol and dipentaerythritol are particularly preferred due to their excellent dehydration and cooling effects and ability to form a carbonized insulation layer. The content of the carbonizing agent is preferably 10 to 200 parts by weight (more preferably 20 to 120 parts by weight) per 100 parts by weight of the resin component (solid content). The carbonizing agent of the present invention dehydrates and carbonizes the resin component in response to a temperature rise, such as during a fire, thereby forming a carbonized insulation layer.

Flame retardants include, for example, organic phosphorus compounds such as tricresyl phosphate and diphenyl cresyl phosphate; chlorine compounds such as chlorinated polyphenyls, chlorinated polyethylene, diphenyl chloride, triphenyl chloride, chlorinated paraffins, pentachlorinated fatty acid esters, perchloropentacyclodecane, chlorinated naphthalene, and tetrachlorophthalic anhydride; antimony compounds such as antimony trioxide and antimony pentachloride; phosphorus compounds such as phosphorus trichloride, phosphorus pentachloride, ammonium phosphate, ammonium polyphosphate, melamine phosphate, melam polyphosphate, boron phosphate, boron polyphosphate, aluminum phosphate, and aluminum polyphosphate; and inorganic compounds such as zinc borate and sodium borate. These can be used alone or in combination. The content of the flame retardant is preferably 100 to 1,000 parts by weight (more preferably 200 to 800 parts by weight) per 100 parts by weight of the resin component (solid content).

Furthermore, the first coating material may contain fillers, fibers, etc. Examples of fillers include talc, calcium carbonate, sodium carbonate, aluminum oxide (alumina), titanium oxide, zinc oxide, silica, clay, shirasu, mica, silica sand, silica stone powder, quartz powder, barium sulfate, aluminum hydroxide, magnesium hydroxide, etc. These may be used alone or in combination of two or more. Examples of fibers include organic fibers such as acrylic fiber, acetate fiber, aramid fiber, cuprammonium fiber (cupra), nylon fiber, novoloid fiber, pulp fiber, viscose rayon, vinylidene fiber, polyester fiber, polyethylene fiber, polyvinyl chloride fiber, polychlor fiber, boronosic fiber, polypropylene fiber, and cellulose fiber; and inorganic fibers such as carbon fiber, rock wool fiber, glass fiber, silica fiber, alumina fiber, silica-alumina fiber, slag wool fiber, ceramic fiber, carbon fiber, and silicon carbide fiber. These may be used alone or in combination of two or more.

The second coating material of the present invention preferably contains, in addition to the resin component, a powder component such as a color pigment or an extender pigment. This increases the cohesive force during coating formation, resulting in superior effects in terms of adhesion, etc. To achieve this effect, it is desirable for the powder component to be contained in an amount of 1 to 200 parts by weight (preferably 5 to 150 parts by weight) per 100 parts by weight of the total solids content of the polyol component (A2) and the polyisocyanate component (B2). Examples of color pigments include titanium oxide, zinc oxide, carbon black, graphite, black iron oxide, iron-manganese composite oxide, iron-copper-manganese composite oxide, iron-chromium composite oxide, iron-chromium-cobalt composite oxide, copper-chromium composite oxide, copper-manganese-chromium composite oxide, copper-magnesium composite oxide, bismuth-manganese composite oxide, red iron oxide, molybdate orange, permanent red, permanent carmine, anthraquinone red, perylene red, quinacridone red, yellow iron oxide, titanium yellow, fast yellow, benzimidazolone yellow, chrome green, cobalt green, phthalocyanine green, ultramarine blue, Prussian blue, cobalt blue, phthalocyanine blue, quinacridone violet, dioxazine violet, aluminum pigments, and pearl pigments. These can be used alone or in combination. Examples of extender pigments include heavy calcium carbonate, clay, kaolin, talc, precipitated barium sulfate, barium carbonate, white carbon, and diatomaceous earth.

The coating material of the present invention can be applied by mixing a base agent containing a polyol component (A) with a curing agent containing a polyisocyanate component (B) immediately before application. The solvent can be contained in either the base agent, the curing agent, or both. Furthermore, in the present invention, a solvent can be mixed as a diluent during application, separate from the base agent and curing agent. In particular, the solvent content of the second coating material is preferably 5 to 500 parts by weight (preferably 10 to 400 parts by weight, more preferably 20 to 300 parts by weight) per 100 parts by weight of the total solids content of components (A) and (B). A solvent content within this range is advantageous in terms of preventing plasticizer migration and the finish quality of the topcoat material. In particular, it is desirable for the solids content of the coating material of the present invention after dilution to be 25 to 90% by weight (preferably 30 to 85% by weight). Within this range, the above-mentioned effects can be further enhanced.

The coating material of the present invention can be applied using various methods, such as brush coating, roller coating, and spray coating. The amount of coating and the number of coats of the first coating material when applied may be determined according to the functionality of the coating material. The amount of coating of the first coating material when applied is preferably 0.5 to 5.0 kg/m ² (more preferably 0.8 to 3.0 kg/m ² ). The number of coats of the first coating material is preferably 1 to 2.
On the other hand, the amount of the second coating material applied is preferably 30 to 500 g/m ² (more preferably 50 to 300 g/m ² ). The number of coats of the second coating material can be determined appropriately depending on the surface condition of the coating formed by the first coating material, but is preferably 1 to 2 coats. Note that the coating material of the present invention can sufficiently prevent plasticizer migration even with a single coat.

In the present invention, a topcoat can be applied as needed to protect the coating formed by the coating materials (first and second coating materials). Such a topcoat can be formed by applying a known topcoat. Topcoats can be, for example, clear or colored, glossy or matte, hard or elastic, thin or thick. They can also be water-based or solvent-based, and can be selected appropriately depending on the desired purpose.

The topcoat material of the present invention preferably contains a resin component. Examples of such resin forms include solvent-soluble resins, non-aqueous dispersion resins, solventless resins, aqueous dispersion resins, and water-soluble resins. Examples of resin types include acrylic resins, urethane resins, epoxy resins, vinyl chloride resins, vinyl acetate resins, acrylic silicone resins, fluororesins, silicone resins, polyvinyl alcohol, cellulose derivatives, and composites of these. These can be used alone or in combination of two or more. In the present invention, it is particularly preferable to include one or more resins selected from urethane resins, epoxy resins, acrylic resins, acrylic silicone resins, and fluororesins.

Furthermore, the resin component may be crosslinkable. When the resin component is a crosslinkable resin, the water resistance, durability, and adhesion of the formed coating are enhanced, and swelling and peeling of the coating due to rainfall, condensation, etc. can be suppressed. Furthermore, when the first coating material contains a functional powder, various functionalities (e.g., heat resistance, etc.) can be stably maintained. Such crosslinkable resins may undergo crosslinking reactions themselves or may undergo crosslinking reactions when a crosslinking agent is added separately. Such crosslinking reactivity can be imparted by combining reactive functional groups, such as hydroxyl groups and isocyanate groups, carbonyl groups and hydrazide groups, epoxy groups and amino groups, aldo groups and semicarbazide groups, keto groups and semicarbazide groups, alkoxyl groups, carboxyl groups and metal ions, carboxyl groups and carbodiimide groups, carboxyl groups and epoxy groups, carboxyl groups and aziridine groups, and carboxyl groups and oxazoline groups. Among these, it is preferable to use a crosslinking reaction type resin that undergoes a crosslinking reaction between one or more groups selected from the group consisting of a hydroxyl group and an isocyanate group, a carbonyl group and a hydrazide group, and an epoxy group and an amino group.

In addition to the resin component of the topcoat material, other components such as color pigments, extender pigments, and aggregates can be mixed. By appropriately blending these components, the desired color and texture can be achieved. There are no particular restrictions on the amount of color pigments, extender pigments, aggregates, etc. mixed in, as long as it does not impair the effects of the coating material. However, the amount is preferably 1 to 2,000 parts by weight (more preferably 5 to 1,000 parts by weight) per 100 parts by weight of the solids of the resin component.

In the present invention, it is particularly preferable to use pigments that are infrared reflective and/or infrared transparent as the color pigments and extender pigments. This can further enhance the durability of the formed coating.

Examples of infrared-reflective pigments include aluminum flakes, titanium oxide, barium sulfate, zinc oxide, iron oxide, calcium carbonate, silicon oxide, magnesium oxide, zirconium oxide, yttrium oxide, indium oxide, alumina, iron-chromium composite oxide, manganese-bismuth composite oxide, manganese-yttrium composite oxide, black iron oxide, iron-manganese composite oxide, iron-copper-manganese composite oxide, iron-chromium-cobalt composite oxide, copper-chromium composite oxide, and copper-manganese-chromium composite oxide, and one or more of these can be used.

Examples of pigments that are infrared transparent include perylene pigments, azo pigments, yellow lead, titanium red, cadmium red, quinacridone red, isoindolinone, benzimidazolone, phthalocyanine green, phthalocyanine blue, cobalt blue, indanthrene blue, ultramarine, and Prussian blue, and one or more of these can be used.

Furthermore, topcoat materials can also be blended with various other additives that can be used in regular paints. Examples of such additives include thickeners, film-forming aids, leveling agents, wetting agents, plasticizers, antifreeze agents, pH adjusters, preservatives, antifungal agents, anti-algae agents, antibacterial agents, dispersants, antifoaming agents, adsorbents, UV absorbers, light stabilizers, antioxidants, fibers, anti-fouling agents, hydrophilizing agents, water repellents, coupling agents, catalysts, etc.

The topcoat material can be applied according to a known application method, for example, by using various methods such as brush coating, roller coating, and spray coating. The amount of coating is preferably 30 to 5000 g/m ² (more preferably 50 to 3000 g/m ² ). The number of coats of the topcoat material can be set appropriately, but is preferably 1 to 2 times. In addition, drying is preferably performed at room temperature.

The present invention provides a laminate having a first coating formed from the first coating material and a second coating formed from the second coating material. The laminate of the present invention exhibits excellent plasticizer migration prevention properties and excellent adhesion. Furthermore, by having a top coat layer formed from a top coat material on the second coating, the laminate of the present invention exhibits excellent plasticizer migration prevention properties, excellent adhesion, and improved aesthetics and weather resistance.

The following examples will clarify the features of the present invention. However, the present invention is not limited to these scopes.

<Coating material>
(Main ingredients 1 to 15)
According to the formulation shown in Table 1, component (A), color pigment, curing catalyst, and additives were mixed in a conventional manner to prepare a base resin.
The following raw materials were used:

Polyol (A)
Polyether polyol (Ax)
(Ax-1) Polyether polyol (hydroxyl value 17 mg KOH/g, number of functional groups 3, number average molecular weight 10,000, solid content 100% by weight)
(Ax-2) Polyether polyol (hydroxyl value 24 mg KOH/g, number of functional groups 3, number average molecular weight 7000, solid content 100% by weight)
(Ax-3) Polyether polyol (hydroxyl value 55 mg KOH/g, number of functional groups 3, number average molecular weight 3000, solid content 100% by weight)
(Ax-4) Polyether polyol (hydroxyl value 160 mg KOH/g, number of functional groups 3, number average molecular weight 1000, solid content 100% by weight)
(Ax-5) Polyether polyol (hydroxyl value 230 mg KOH/g, number of functional groups 3, number average molecular weight 700, solid content 100% by weight)
(Ax-6) Polyether polyol (hydroxyl value 400 mg KOH/g, number of functional groups 3, number average molecular weight 400, solid content 100% by weight)
Acrylic polyol (Ay)
(Ay-1) Acrylic polyol (hydroxyl value 40 KOH mg/g, solid content 50 wt %, medium: aromatic hydrocarbon compound, ester compound)
(Ay-2) Polyester-containing acrylic polyol (hydroxyl value 40 KOH mg/g, polyester ratio 10 wt%, solid content 50 wt%, medium: aromatic hydrocarbon compound, ester compound)
The component (A) is a liquid at 20°C.

Plasticizer 1: Diisononyl phthalate (molecular weight 419)
Plasticizer 2: Diisononyl adipate (molecular weight 399)
Functional powders: flame retardants, foaming agents, carbonizing agents, etc. Coloring pigments: titanium oxide, average particle size 0.3 μm
Curing catalyst: organometallic catalyst Additive 1: dispersant, defoamer, etc. Additive 2: diluent (aromatic hydrocarbon)

(Curing agent 1)
A curing agent was prepared by mixing 80 parts by weight of polyisocyanate (B) (biuret type hexamethylene diisocyanate, NCO content 23.5%) and 20 parts by weight of a dilution solvent (aromatic hydrocarbon).

(Preparation of Coating Material)
The base materials 1 to 15 shown in Table 1 and the curing agent were mixed so that the NCO/OH equivalent ratio of the polyol component and the polyisocyanate component was 1.2, to obtain coating materials 1 to 15.

<Top coating material>
Acrylic polyol (hydroxyl value 20 KOH mg / g, solid content 50 wt%, medium: aliphatic hydrocarbon compound) 100 parts by weight, titanium dioxide 40 parts by weight, additives (thickener, antifoaming agent) 10 parts by weight were uniformly mixed and stirred in a conventional manner to prepare the base material. Next, 50 parts by weight of polyisocyanate (adduct type hexamethylene diisocyanate, NCO content 12%) and 50 parts by weight of dilution solvent (aliphatic hydrocarbon) were mixed to prepare the curing agent. The base material and the curing agent were mixed so that the NCO / OH equivalent ratio of the polyol component and the polyisocyanate component was 1.0, respectively, to prepare the topcoat material.

(Examples 1 to 12, Comparative Examples 1 to 3)
The following evaluations were carried out for each coating material, and the results are shown in Table 2.

Preparation of Test Specimen [I]: The first coating material was sprayed onto a 150 mm x 70 mm steel plate at 1.5 kg/ ^m² and cured for 7 days. Next, the second coating material was brushed on at a coating amount of 100 g/ ^m² and cured for 24 hours to prepare Test Specimen [I]. The combinations of the first and second coating materials are shown in Table 2. The painting, curing, etc. were all carried out under standard conditions (temperature 23°C, relative humidity 50%).
<Evaluation of plasticizer migration prevention ability>
The prepared specimen [I] was left in an incubator at 50°C or 80°C for one week. The specimen was removed from the incubator, placed horizontally, and black silica sand was sprinkled on it. The specimen was then immediately stood upright and the black silica sand was allowed to fall naturally. The extent of the adhered black silica sand was visually confirmed to evaluate the plasticizer migration prevention property.
The evaluation was made on a four-point scale (A>B>C>D), with "A" indicating that almost no black silica sand had adhered and "D" indicating that significant black silica sand had adhered.

<Adhesion Evaluation 1>
The prepared specimen [I] was evaluated for adhesion to the surface of the plasticizer-containing material by the cross-cut tape method in accordance with JIS K 5600-5-6. The evaluation criteria were as follows:
A: The area of the defective portion is less than 10%. B: The area of the defective portion is 10% or more but less than 25%. C: The area of the defective portion is 25% or more but less than 50%. D: The area of the defective portion is 50% or more.

In Examples 1 to 12, good plasticizer migration prevention properties were obtained and a coating with good adhesion was formed. In particular, Examples 6 to 11 demonstrated excellent plasticizer migration prevention properties, and furthermore, Examples 5 to 11 were able to form a coating with excellent adhesion.

Next, the following evaluations were carried out for Examples 6 to 11. The results are shown in Table 2.
Preparation of Test Specimen [II]: The first coating material was sprayed onto a 150 mm x 70 mm steel plate at 1.5 kg/ ^m² and cured for 7 days. Next, the second coating material was brushed onto the plate at a coating amount of 100 g/ ^m² and cured for 24 hours. The combinations of the first and second coating materials are shown in Table 2.
Next, the topcoat material was spray-painted at a coating amount of 0.3 kg/m ² and cured for 72 hours to prepare a test specimen. All painting, curing, etc. were performed under standard conditions (temperature 23 ° C., relative humidity 50%).

<Adhesion Evaluation 2>
The prepared specimen [II] was evaluated for adhesion to the coating material and topcoat material by the cross-cut tape method according to JIS K 5600-5-6. The evaluation criteria are the same as those in Adhesion Evaluation 1 above.

<Heat resistance protection evaluation>
The prepared specimen [II] was left in an incubator at 80°C for one week, and then the resulting specimen was subjected to radiant heat of 50 kW/m² on the surface of the specimen for 15 minutes using an electric heater (CONE III, manufactured by Toyo Seiki Co., Ltd.) according to ISO 5660-1 cone calorimeter method, and the expansion ratio and the backside temperature of the steel plate were measured. The evaluation criteria were as follows. The results are shown in Table 2.
(Expansion ratio)
AA: Expansion ratio greater than 35 times A: Expansion ratio greater than 25 times and less than 35 times B: Expansion ratio greater than 20 times and less than 25 times C: Expansion ratio greater than 15 times and less than 20 times D: Expansion ratio less than 15 times (rear surface temperature)
AA: Less than 430°C A: 430°C or higher and lower than 470°C B: 470°C or higher and lower than 500°C C: 500°C or higher and lower than 550°C D: 550°C or higher

In Examples 6 to 11, a carbonized heat insulating layer was formed with excellent foaming properties, and heat-resistant protection of the substrate was achieved.

Claims (6)

A coating formation method comprising applying a first coating material and drying it, and then applying a second coating material to the surface of the coating (first coating),
the first coating material contains a plasticizer,
The first coating material and the second coating material each contain a polyol component (A) and a polyisocyanate component (B) as resin components,
the second coating material contains a polyol component (A2) having a hydroxyl value greater than that of the polyol component (A1) of the first coating material,
The method for forming a coating film, wherein the second coating material contains a polyether polyol (Ax2) and an acrylic polyol (Ay2) as the polyol component (A2). the first coating material contains a polyether polyol (Ax1) as the polyol component (A),
2. The coating method according to claim 1, wherein the second coating material contains a polyether polyol (Ax2) having a hydroxyl value greater than that of the polyether polyol (Ax1) of the first coating material. 2. The method for forming a coating film according to claim 1, wherein the polyether polyol (Ax2) contains a polyether polyol having a hydroxyl value of 50 mg KOH/g or more. The coating formation method described in claim 1, characterized in that the weight ratio (solid content) of the polyether polyol (Ax2) to the acrylic polyol (Ay2) is 90:10 to 10:90. The coating formation method described in claim 1, further comprising applying a topcoat material. A laminate having a second coating formed from a second coating material on a surface of a first coating formed from a first coating material,
the first coating material contains a plasticizer,
The first coating material and the second coating material each contain a polyol component (A) and a polyisocyanate component (B) as resin components,
the second coating material contains a polyol component (A2) having a hydroxyl value greater than that of the polyol component (A1) of the first coating material,
The second coating material is a laminate comprising a polyether polyol (Ax2) and an acrylic polyol (Ay2) as the polyol component (A2).