Two-component curing coating agent and multi-layer film

Abstract

To provide a two-liquid curable coating agent capable of forming a surface protective layer excellent in weatherability, acid resistance, antifouling property and extensibility and to provide a multilayer film having a surface protective layer which is a cured film of the two-liquid curable coating agent.SOLUTION: There is provided a two-liquid curable coating agent which comprises a main agent containing a polyol including an acrylic polyol having a hydroxyl value of 36 mgKOH / g or more and 125 mgKOH / g or less and containing an alicyclic structure and an alkyl polyol and a curing agent containing a polyisocyanate. Further, there is provided a multilayer film containing a substrate layer and a surface protective layer which is integrally laminated on a first surface of the substrate layer and is a cured film of the two-liquid curable coating agent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a two-component curing coating agent capable of forming a surface protective layer that is excellent in weather resistance, acid resistance, antifouling properties, and elongation, and to a multilayer film having a surface protective layer that is a cured film of the two-component curing coating agent. [Background technology]

[0002] Conventionally, surface treatments have been performed on articles such as automobiles, vehicles, aircraft, glass, buildings, and signs to protect their surfaces from dirt and scratches and maintain their appearance. Such surface treatments are performed by applying a surface protective layer to the surface of the article. Examples of surface treatment methods include (1) a method in which a coating agent is applied to the surface of the article to form a surface protective layer, and (2) a method in which a multilayer film having a surface protective layer and an adhesive layer is attached to the surface of the article.

[0003] The surface protective layer contains polyurethane obtained by reacting an acrylic polymer having hydroxyl groups with a polyisocyanate. For example, Patent Document 1 discloses a coating agent containing a urethane-modified acrylic resin. Patent Document 1 also discloses that the urethane-modified acrylic resin is obtained by a urethane reaction of an acrylic polyol (A) having an alicyclic skeleton, a hydroxyl value of 5 to 35 mgKOH / g, and a weight-average molecular weight of 5,000 to 30,000, a polyol (B) having an alicyclic skeleton other than the acrylic polyol, and an organic diisocyanate (C). Patent Document 1 limits the hydroxyl value of the acrylic polyol (A) to 5 to 35 mgKOH / g, excluding hydroxyl values ​​exceeding 35 mgKOH / g due to gelation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-153204 Summary of the Invention [Problem to be solved by the invention]

[0005] Surface-treated articles are often used outdoors. Therefore, surface-treated articles are exposed to wind, rain, and high-humidity environments, or are exposed to light, including ultraviolet light, for long periods of time. In such cases, unevenness or discoloration may occur in the surface protective layer. Specifically, unevenness may first occur in a portion of the surface of the surface protective layer. Over time, the unevenness gradually spreads across the surface of the surface protective layer, resulting in discoloration of the surface protective layer to yellow, white, or other colors. Eventually, the unevenness may spread across the entire surface of the surface protective layer, resulting in the entire surface protective layer discoloring to yellow, white, or other colors. The occurrence of such unevenness or discoloration in the surface protective layer is thought to be due to degradation of components contained in the surface protective layer due to light, or the adhesion of solutes contained in rain or moisture in the air to the surface of the surface protective layer. The occurrence of unevenness or discoloration in the surface protective layer leads to poor appearance of the surface protective layer. Therefore, the surface protective layer is required to have excellent weather resistance.

[0006] Furthermore, when the surface of a surface-treated article comes into contact with acid rain due to rainfall, the surface protective layer may whiten, resulting in poor appearance. Therefore, the surface protective layer is also required to have excellent acid resistance.

[0007] Furthermore, adhesion of oily stains such as fingerprints to the surface protective layer can also cause poor appearance, and therefore the surface protective layer is required to have excellent antifouling properties so that even if oily stains adhere to the surface protective layer, they can be easily wiped off.

[0008] Furthermore, a tensile force may be applied to the surface protective layer when the surface protective layer is attached to the surface of an article or when a surface-treated article is molded. However, if the surface protective layer has low elongation, the surface protective layer may not be able to withstand the tensile force and may crack or break. Therefore, the surface protective layer is also required to have excellent elongation.

[0009] As mentioned above, Patent Document 1 discloses a coating agent containing a urethane-modified acrylic resin, but the surface protective layer formed using this coating agent has problems such as poor weather resistance, acid resistance, and stain resistance.

[0010] Therefore, an object of the present invention is to provide a two-component curing coating agent capable of forming a surface protective layer that is excellent in weather resistance, acid resistance, antifouling properties, and elongation, and a multilayer film having a surface protective layer that is a cured film of the two-component curing coating agent. [Means for solving the problem]

[0011] <Two-component curing coating agent> The two-component curing coating agent of the present invention is characterized by comprising a base agent containing an acrylic polyol having a hydroxyl value of 36 mgKOH / g or more and 125 mgKOH / g or less and containing an alicyclic structure, and a polyol containing an alkyl polyol, and a curing agent containing a polyisocyanate.

[0012] In the two-component curing coating agent of the present invention, a surface protective layer can be formed by reacting the polyol contained in the base agent with the polyisocyanate contained in the curing agent to form polyurethane, thereby curing the two-component curing coating agent. In the two-component curing coating agent of the present invention, the base polyol contains an acrylic polyol having a hydroxyl value of 36 mgKOH / g or more and 125 mgKOH / g or less and containing an alicyclic structure, thereby forming a surface protective layer with excellent acid resistance, weather resistance, and antifouling properties. On the other hand, the alicyclic structure of the acrylic polyol can reduce the elongation of the surface protective layer. However, in the two-component curing coating agent of the present invention, the base polyol further contains an alkyl polyol, thereby forming a surface protective layer with excellent elongation despite the use of the above-mentioned acrylic polyol. Furthermore, the alkyl polyol can also improve the antifouling properties of the surface protective layer.

[0013] As described above, in the two-component curing coating agent of the present invention, by using a combination of a specific acrylic polyol and an alkyl polyol as the polyol contained in the main agent, it is possible to form a surface protective layer that is excellent in weather resistance, acid resistance, antifouling properties, and elongation.

[0014] [Main ingredient] The two-component curing coating agent of the present invention includes a base agent containing a polyol. The polyol contained in the base agent includes an acrylic polyol and an alkyl polyol.

[0015] (acrylic polyol) The polyol contained in the base material of the two-component curing coating agent of the present invention includes an acrylic polyol having a hydroxyl value of 36 mg KOH / g or more and 125 mg KOH / g or less and containing an alicyclic structure.

[0016] In the present invention, the term "alicyclic structure" refers to a structure in which carbon atoms are bonded in a ring shape and which does not have aromaticity. Furthermore, "aromaticity" refers to a ring structure that conforms to the Hückel rule and has (4n+2) π electrons (n ​​is a natural number).

[0017] Examples of the alicyclic structure in the acrylic polyol include cycloalkane structures such as cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane structure, cyclooctane structure, and cyclodecane structure, tetrahydrodicyclopentadiene structure, adamantane structure, and isobornyl structure. The alicyclic structure is preferably a cycloalkane structure. The acrylic polyol may contain one type of alicyclic structure or two or more types of alicyclic structures.

[0018] Acrylic polyol is an acrylic polymer obtained by polymerizing a (meth)acrylic monomer and having a hydroxyl group at the end or in the side chain. The acrylic polyol can be obtained by polymerizing a (meth)acrylic monomer in the presence of a radical polymerization initiator using a conventional method for producing an acrylic polymer.

[0019] Here, (meth)acrylic means acrylic or methacrylic, and (meth)acrylate means acrylate or methacrylate.

[0020] (Hydroxyl group-containing (meth)acrylic monomer) The acrylic polyol preferably contains a hydroxyl group-containing (meth)acrylic monomer component, that is, the acrylic polyol is preferably a polymer of a (meth)acrylic monomer containing a hydroxyl group-containing (meth)acrylic monomer.

[0021] Examples of hydroxyl group-containing (meth)acrylic monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate. Among these, 2-hydroxyethyl (meth)acrylate is preferred. The hydroxyl group-containing (meth)acrylic monomers may be used alone or in combination of two or more.

[0022] The content of the hydroxyl group-containing (meth)acrylic monomer component in the acrylic polyol is preferably 8% by mass or more, more preferably 9% by mass or more, and particularly preferably 10% by mass or more. The content of the hydroxyl group-containing (meth)acrylic monomer component in the acrylic polyol is preferably 27% by mass or less, more preferably 26% by mass or less, and particularly preferably 25% by mass or less. When the content of the hydroxyl group-containing (meth)acrylic monomer component is 8% by mass or more, the hydroxyl value of the acrylic polyol can be easily adjusted to 36 mgKOH / g or more. This makes it possible to form a surface protective layer that has excellent acid resistance, weather resistance, and antifouling properties. When the content of the hydroxyl group-containing (meth)acrylic monomer component is 27% by mass or less, the surface protective layer can maintain excellent elongation.

[0023] ((Meth)acrylic monomer having an alicyclic structure) The acrylic polyol preferably further contains a (meth)acrylic monomer component having an alicyclic structure. Therefore, the acrylic polyol preferably contains a hydroxyl group-containing (meth)acrylic monomer component and a (meth)acrylic monomer component having an alicyclic structure. That is, the acrylic polyol is preferably a polymer of a (meth)acrylic monomer containing a hydroxyl group-containing (meth)acrylic monomer and a (meth)acrylic monomer having an alicyclic structure.

[0024] By using a (meth)acrylic monomer having an alicyclic structure, an acrylic polyol having an alicyclic structure can be easily obtained, and such an acrylic polyol can form a surface protective layer having excellent acid resistance, weather resistance, and antifouling properties.

[0025] In addition, the (meth)acrylic monomer having an alicyclic structure preferably does not have a hydroxyl group.

[0026] Examples of the alicyclic structure in the (meth)acrylic monomer having an alicyclic structure include cycloalkane structures such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cyclooctane structure, and a cyclodecane structure, a tetrahydrodicyclopentadiene structure, an adamantane structure, an isobornyl structure, etc. As the alicyclic structure, a cycloalkane structure is preferred.

[0027] Specific examples of (meth)acrylic monomers having an alicyclic structure include isobornyl acrylate, isobornyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, dicyclopentanyl acrylate, 1,4-cyclohexanedimethanol monoacrylate, 1-ethylcyclohexyl acrylate, 1-ethylcyclooctyl acrylate, 2-methyl-2-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, and adamantyloxymethyl methacrylate. The (meth)acrylic monomers having an alicyclic structure may be used alone or in combination of two or more.

[0028] Among these, as the (meth)acrylic monomer having an alicyclic structure, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, and isobornyl methacrylate are preferred, cyclohexyl acrylate and cyclohexyl methacrylate are more preferred, and cyclohexyl methacrylate is even more preferred.

[0029] In the acrylic polyol, the content of the (meth)acrylic monomer component having an alicyclic structure is preferably 10% by mass or more, more preferably 15% by mass or more, and particularly preferably 20% by mass or more. In the acrylic polyol, the content of the (meth)acrylic monomer component having an alicyclic structure is preferably 50% by mass or less, more preferably 45% by mass or less, and particularly preferably 42% by mass or less. When the content of the (meth)acrylic monomer component having an alicyclic structure is 10% by mass or more, a surface protective layer having excellent acid resistance, weather resistance, antifouling properties, and elongation can be formed. When the content of the (meth)acrylic monomer component having an alicyclic structure is 50% by mass or less, the surface protective layer can maintain excellent elongation.

[0030] (Alkyl (meth)acrylate) The acrylic polyol preferably further contains an alkyl (meth)acrylate component. Therefore, the acrylic polyol preferably contains a hydroxyl group-containing (meth)acrylic monomer component, a (meth)acrylic monomer component having an alicyclic structure, and an alkyl (meth)acrylate component. That is, the acrylic polyol is preferably a polymer of a hydroxyl group-containing (meth)acrylic monomer, a (meth)acrylic monomer having an alicyclic structure, and a (meth)acrylic monomer containing an alkyl (meth)acrylate. The acrylic polyol is more preferably a copolymer of a hydroxyl group-containing (meth)acrylic monomer, a (meth)acrylic monomer having an alicyclic structure, and an alkyl (meth)acrylate.

[0031] The alkyl(meth)acrylate preferably does not have an alicyclic structure, and the alkyl(meth)acrylate preferably does not have a hydroxyl group.

[0032] The alkyl group in the alkyl (meth)acrylate is -C n H 2n+1 (n is a natural number), and a linear or branched alkyl group is preferred.

[0033] Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and myristyl (meth)acrylate. The alkyl (meth)acrylates may be used alone or in combination of two or more.

[0034] Of these, as the alkyl(meth)acrylate, butyl(meth)acrylate, lauryl(meth)acrylate, and myristyl(meth)acrylate are preferred, and butyl(meth)acrylate and lauryl(meth)acrylate are more preferred.

[0035] The content of the alkyl (meth)acrylate component in the acrylic polyol is preferably 30% by mass or more, more preferably 35% by mass or more, and particularly preferably 42% by mass or more. The content of the alkyl (meth)acrylate component in the acrylic polyol is preferably 80% by mass or less, more preferably 70% by mass or less, and particularly preferably 66% by mass or less. When the content of the alkyl (meth)acrylate component is 30% by mass or more, the surface protective layer can be imparted with excellent elongation. When the content of the alkyl (meth)acrylate component is 80% by mass or less, the surface protective layer can be imparted with excellent acid resistance.

[0036] As a method for polymerizing acrylic polyol, a conventionally known method can be used. For example, a method of polymerizing the above-mentioned monomer in the presence of a radical polymerization initiator can be used. For example, a method of supplying the above-mentioned monomer, polymerization initiator, and polymerization solvent into a reactor and heating at a temperature of 60 to 80°C for 4 to 48 hours to radically polymerize the monomer can be used.

[0037] The hydroxyl value of the acrylic polyol is 36 mgKOH / g or more, preferably 54 mgKOH / g or more, and more preferably 68 mgKOH / g or more. The hydroxyl value of the acrylic polyol is 125 mgKOH / g or less, preferably 90 mgKOH / g or less, and more preferably 70 mgKOH / g or less. When the hydroxyl value of the acrylic polyol is 36 mgKOH / g or more, a surface protective layer having excellent weather resistance, acid resistance, antifouling properties, and elongation can be formed. When the hydroxyl value of the acrylic polyol is 125 mgKOH / g or less, the surface protective layer can maintain excellent elongation.

[0038] The hydroxyl value of the acrylic polyol refers to the value measured in accordance with 4.2 Method B of JIS K 1557-1:2007 (ISO 14900:2001) "Plastics - Test methods for polyurethane raw polyols - Part 1: Determination of hydroxyl value."

[0039] The glass transition temperature of the acrylic polyol is preferably -60°C or higher, more preferably -50°C or higher, and particularly preferably -42°C or higher. The glass transition temperature of the acrylic polyol is preferably 0°C or lower, more preferably -1°C or lower, and particularly preferably -2°C or lower. When the glass transition temperature of the acrylic polyol is -60°C or higher, the acid resistance and stain resistance of the surface protective layer can be improved. When the glass transition temperature of the acrylic polyol is 0°C or lower, the elongation of the surface protective layer can be improved.

[0040] The glass transition temperature of the acrylic polyol can be calculated from the Fox equation shown in the following formula (1) using the content ratio (weight fraction) of each monomer constituting the acrylic polyol and the glass transition temperature of each monomer.

[0041]

number

[0042] The "glass transition temperature of monomer i" refers to the glass transition temperature of a homopolymer obtained by homopolymerizing monomer i. The glass transition temperature of the homopolymer of monomer i is measured by differential scanning calorimetry (DSC) in accordance with JIS K7121 (1987), and the measured value thus obtained is referred to as the "glass transition temperature of monomer i."

[0043] The weight-average molecular weight of the acrylic polyol is preferably 8,000 or more, more preferably 9,000 or more, and particularly preferably 10,000 or more. The weight-average molecular weight of the acrylic polyol is preferably 120,000 or less, more preferably 110,000 or less, and particularly preferably 100,000 or less. When the weight-average molecular weight of the acrylic polyol is 8,000 or more, the acid resistance and weather resistance of the surface protective layer can be improved. When the weight-average molecular weight of the acrylic polyol is 120,000 or less, the excellent elongation of the surface protective layer can be maintained, and the antifouling properties of the surface protective layer can also be improved.

[0044] The weight-average molecular weight of the acrylic polyol refers to a value obtained by converting the molecular weight measured by gel permeation chromatography (GPC) into polystyrene equivalent. For example, it can be measured under the following measurement conditions.

[0045] Acrylic polyol is dissolved in tetrahydrofuran to obtain a measurement sample with an acrylic polyol concentration of 2.0 g / L. Using this measurement sample, the weight-average molecular weight of the acrylic polyol is measured using a gel permeation chromatograph (GPC) equipped with a refractive index detector (RID). The weight-average molecular weight of the acrylic polyol can be measured using the following measurement device and measurement conditions. Measuring device: Tosoh Corporation, product name "HLC-8320GPC" Refractive index detector: RI detector built into the above measurement device Column: Two "TSKgel SuperHZM-H" columns manufactured by Tosoh Corporation Mobile phase: tetrahydrofuran Column flow rate: 0.35 mL / min Sample concentration: 2.0 g / L Injection volume: 10μL Measurement temperature: 40℃ Molecular weight marker: Standard polystyrene (Polymer Laboratories Ltd. standard material) (POLYSTYRENE-MEDIUM MOLECULAR WEIGHT CALIBRATION KIT)

[0046] In the two-component curing coating agent of the present invention, the content of the acrylic polyol in the polyol contained in the base agent is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, and particularly preferably 35 parts by mass or more, per 100 parts by mass of the total amount of the acrylic polyol and alkyl polyol. The content of the acrylic polyol in the polyol contained in the base agent is preferably 98 parts by mass or less, more preferably 94 parts by mass or less, and particularly preferably 90 parts by mass or less, per 100 parts by mass of the total amount of the acrylic polyol and alkyl polyol. When the content of the acrylic polyol is 25 parts by mass or more, a surface protective layer having excellent weather resistance, acid resistance, antifouling properties, and elongation can be formed. When the content of the acrylic polyol is 98 parts by mass or less, a surface protective layer having excellent weather resistance, acid resistance, antifouling properties, and elongation can be formed.

[0047] (Alkyl polyol) The polyol contained in the base material of the two-component curing coating agent of the present invention includes alkyl polyols in addition to the above-mentioned acrylic polyols.

[0048] In the present invention, "alkyl polyol" refers to a saturated hydrocarbon having a chain or saturated alicyclic structure, in which at least two hydrogen atoms in one molecule have been substituted with hydroxyl groups (-OH).

[0049] A chain saturated hydrocarbon in which at least two hydrogen atoms in one molecule are substituted with hydroxyl groups (-OH) is called a "chain alkyl polyol."

[0050] A saturated hydrocarbon having a saturated alicyclic structure in which at least two hydrogen atoms in one molecule are replaced with hydroxyl groups (-OH) is called a "cycloalkyl polyol."

[0051] The term "saturated alicyclic structure" refers to an alicyclic structure that does not contain unsaturated bonds such as carbon-carbon double bonds or carbon-carbon triple bonds. Examples of saturated alicyclic structures include cycloalkane structures such as cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane structure, cyclooctane structure, and cyclodecane structure, tetrahydrodicyclopentadiene structure, and adamantane structure. Examples of saturated hydrocarbons having a saturated alicyclic structure include dimethylcyclohexane, diethylcyclohexane, adamantane, tetrahydrodicyclopentadiene, and tetramethylcyclobutane.

[0052] The alkyl polyol has two or more hydroxyl groups per molecule. The alkyl polyol has preferably five or less hydroxyl groups per molecule, more preferably three or less hydroxyl groups per molecule. The alkyl polyol particularly preferably has two hydroxyl groups per molecule.

[0053] Specific examples of alkyl polyols include: Propanediol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,4-diethyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 2-methyl-1,6-hexanediol, 2-methyl-2-ethyl-1,3-propanediol linear alkyl polyols such as 2-methyl-2-propyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 1,3,5-trimethyl-1,3-pentanediol, and 2,2,4-trimethyl-1,6-hexanediol; and Examples of the alkyl polyol include cyclohexane dimethanols such as 1,2-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, and 1,4-cyclohexane dimethanol, cyclohexane diethanols such as 1,2-cyclohexane diethanol, 1,3-cyclohexane diethanol, and 1,4-cyclohexane diethanol, and cycloalkyl polyols such as tricyclodecane dimethanol, adamantane diol, and 2,2,4,4-tetramethyl-1,3-cyclobutane diol. The alkyl polyols may be used alone or in combination of two or more.

[0054] Among these, the alkyl polyol is preferably a cycloalkyl polyol, more preferably cyclohexanedimethanol or cyclohexanediethanol, and more preferably cyclohexanedimethanol. By using a cycloalkyl polyol, the antifouling properties of the surface protective layer can be further improved.

[0055] The content of cycloalkyl polyol in the alkyl polyol is preferably 75% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass. It is particularly preferable that the alkyl polyol consists solely of cycloalkyl polyol. When the content of cycloalkyl polyol is 75% by mass or more, the antifouling properties of the surface protective layer can be improved.

[0056] In the two-component curing coating agent of the present invention, the content of alkyl polyol in the polyol contained in the base agent is preferably 2 parts by mass or more, more preferably 6 parts by mass or more, and particularly preferably 10 parts by mass or more, per 100 parts by mass of the total amount of acrylic polyol and alkyl polyol. The content of alkyl polyol in the polyol contained in the base agent is preferably 75 parts by mass or less, more preferably 70 parts by mass or less, and particularly preferably 65 parts by mass or less, per 100 parts by mass of the total amount of acrylic polyol and alkyl polyol. When the content of alkyl polyol is 2 parts by mass or more, the antifouling properties of the surface protective layer can be improved. When the content of alkyl polyol is 75 parts by mass or less, the surface protective layer can be imparted with excellent elongation and can also maintain excellent acid resistance.

[0057] The main component of the two-component curing coating agent may contain a curing catalyst. Examples of the curing catalyst include organometallic compounds such as dibutyltin oxide, tin 2-ethylcaproate, tin octoate, and dibutyltin dilaurate. The curing catalyst may be used alone or in combination.

[0058] [Hardening agent] The two-component curing coating agent of the present invention contains a curing agent containing polyisocyanate. The polyisocyanate has two or more isocyanate groups (-NCO) per molecule, preferably three or more. Polyisocyanate having three or more isocyanate groups per molecule can improve the stain resistance of the surface protective layer.

[0059] Examples of polyisocyanates include aliphatic polyisocyanates and polyisocyanates having an alicyclic structure. The polyisocyanates may be used alone or in combination of two or more.

[0060] Examples of aliphatic polyisocyanates include acyclic aliphatic polyisocyanates such as ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate. Of these, hexamethylene diisocyanate is preferred.

[0061] Examples of polyisocyanates having an alicyclic structure include 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), isophorone diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), and 1,3-bis(isocyanatomethyl)cyclohexane (hydrogenated m-XDI).

[0062] Examples of polyisocyanates include modified polyisocyanates. Modified polyisocyanates include isocyanurates, biurets, and adducts of polyisocyanates. Three molecules of polyisocyanate can form an isocyanurate or biuret. Furthermore, a trimer adduct is formed by reacting three molecules of polyisocyanate with trimethylolpropane.

[0063] Examples of modified polyisocyanates include: Biuret and isocyanurate derivatives of aliphatic polyisocyanates such as ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, and dodecamethylene diisocyanate; Biuret and isocyanurate derivatives of polyisocyanates with alicyclic structures, such as 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), isophorone diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), and 1,3-bis(isocyanatomethyl)cyclohexane (hydrogenated m-XDI); Trimer adduct of trimethylolpropane (TMP) and hydrogenated MDI; A trimer adduct of 3 moles of any one of polyisocyanates such as isophorone diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), and 1,3-bis(isocyanatomethyl)cyclohexane (hydrogenated m-XDI) with 1 mole of trimethylolpropane (TMP); An adduct of trimethylolpropane (TMP) with 2 moles of isophorone diisocyanate and 1 mole of hexamethylene diisocyanate (HDI); and Examples include bifunctional polyurethane diisocyanates obtained by addition reaction of diol with aliphatic diisocyanates such as ethylene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate.

[0064] As the polyisocyanate, a biuret of polyisocyanate and an isocyanurate of polyisocyanate are preferred, an isocyanurate of polyisocyanate is more preferred, and an isocyanurate of aliphatic polyisocyanate is particularly preferred. These polyisocyanates can form a surface protective layer that is excellent in weather resistance, acid resistance, and antifouling properties.

[0065] In two-component curing coating agents, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate groups of the polyisocyanate contained in the curing agent to the hydroxyl groups of the polyol contained in the base agent is preferably 0.8 or more, more preferably 0.9 or more. In two-component curing coating agents, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate groups of the polyisocyanate contained in the curing agent to the hydroxyl groups of the polyol contained in the base agent is preferably 1.2 or less, more preferably 1.1 or less. By setting the equivalent ratio (isocyanate group / hydroxyl group) to 0.8 or more, a surface protective layer with excellent antifouling properties can be formed. By setting the equivalent ratio (isocyanate group / hydroxyl group) to 1.2 or less, a surface protective layer with excellent weather resistance can be formed.

[0066] The equivalent ratio (isocyanate groups / hydroxyl groups) of the isocyanate groups of the polyisocyanate contained in the curing agent to the hydroxyl groups of the polyol contained in the base resin is determined by dividing the number of isocyanate groups in the polyisocyanate by the number of hydroxyl groups in the entire polyol.

[0067] The polyol contained in the base resin includes multiple types of polyols such as acrylic polyol and alkyl polyol, etc. Therefore, the number of hydroxyl groups in the entire polyol is calculated based on the following formula. Number of hydroxyl groups in the entire polyol =(W1×H1 / 56100)+(W2×H2 / 56100)+···+(W m ×H m / 56100) (In the formula, W m is the content (g) of the mth polyol in the total polyols, and H m is the hydroxyl value of the mth polyol, and m is an integer representing the number of types of polyol.

[0068] The hydroxyl value of the m-th polyol is the value obtained by measurement in accordance with 4.2 B method of JIS K 1557-1:2007 (ISO 14900:2001) "Plastics - Test methods for polyurethane raw polyols - Part 1: Determination of hydroxyl value."

[0069] The number of isocyanate groups in a polyisocyanate is calculated based on the following formula: The isocyanate equivalent is the value obtained by dividing the molecular weight of a polyisocyanate by the number of isocyanate groups in one molecule. Specifically, it is the value measured in accordance with JIS K1603. Number of isocyanate groups in polyisocyanate = Polyisocyanate content (g) / Isocyanate equivalent

[0070] The base material and curing agent of the two-component curing coating agent may contain additives as needed, as long as the physical properties of the two-component curing coating agent are not impaired. Examples of additives include antioxidants, light stabilizers, heat stabilizers, antistatic agents, and antifoaming agents.

[0071] The base agent and curing agent of the two-component curing coating agent may contain a solvent. When the base agent of the two-component curing coating agent contains a solvent, the solids concentration of the base agent is preferably 10 to 90 mass%, more preferably 20 to 80 mass%. When the curing agent of the two-component curing coating agent contains a solvent, the solids concentration of the curing agent is preferably 10 to 90 mass%, more preferably 20 to 80 mass%.

[0072] Examples of the solvent include hydrocarbons such as pentane, hexane, heptane, and cyclohexane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate and butyl acetate. The solvents may be used alone or in combination.

[0073] The two-component curing coating agent of the present invention is preferably used to form a surface protective layer for protecting the surface of an article. A cured film of the two-component curing coating agent of the present invention can be used as this surface protective layer. The surface protective layer is preferably used as a multilayer film having this surface protective layer. For example, the multilayer film can be attached to the surface of the article using an adhesive or the like to apply the surface protective layer to the surface of the article.

[0074] As described above, the two-component curing coating agent of the present invention can form a surface protective layer that exhibits excellent weather resistance, acid resistance, and antifouling properties. By using such a surface protective layer, the appearance of an article surface can be maintained beautifully for a long period of time. Furthermore, the surface protective layer formed using the two-component curing coating agent of the present invention is flexible and has excellent elongation. A multilayer film including a surface protective layer is attached to the surface of an article by placing the multilayer film on the surface of the article and then pressing and sliding a squeegee over the surface protective layer. During this process, a tensile force is applied to the multilayer film by the squeegee. However, the surface protective layer can withstand this tensile force, thereby reducing the occurrence of cracks or breaks in the surface protective layer. Therefore, the surface protective layer formed using the two-component curing coating agent of the present invention is suitable for use as a multilayer film. The multilayer film including a surface protective layer is described below.

[0075] <Multilayer film> The multilayer film of the present invention includes a substrate layer and a surface protective layer that is integrally laminated on a first surface of the substrate layer and is a cured film of the two-component curing coating agent described above.

[0076] [Base material layer] The multilayer film of the present invention includes a substrate layer. The substrate layer preferably includes at least one of a thermoplastic resin and a thermoplastic elastomer, thereby improving the extensibility of the multilayer film.

[0077] Examples of thermoplastic resins include polyurethane resins, polyolefin resins, polyester resins, polyamide resins, polyvinyl resins, and polycarbonate resins. Examples of thermoplastic elastomers include thermoplastic polyurethane elastomers, thermoplastic styrene elastomers, thermoplastic acrylic elastomers, thermoplastic polyolefin elastomers, thermoplastic polyvinyl chloride elastomers, thermoplastic polyester elastomers, and thermoplastic polyamide elastomers. Each of the thermoplastic resins and thermoplastic elastomers may be used alone or in combination of two or more.

[0078] Among these, the substrate layer preferably contains a thermoplastic resin, more preferably a polyurethane resin. The substrate layer preferably contains a thermoplastic elastomer, more preferably a thermoplastic polyurethane elastomer. The thickness of the substrate layer is not particularly limited, and may be 10 to 300 μm, preferably 20 to 200 μm.

[0079] [Surface protection layer] The multilayer film of the present invention includes a surface protective layer integrally laminated on the first surface of the substrate layer, The surface protective layer is a cured film of the above-mentioned two-component curing coating agent.

[0080] Any surface of the substrate layer is referred to as the “first surface of the substrate layer,” and the surface of the substrate layer opposite to the first surface is referred to as the “second surface of the substrate layer.” It is preferable that one or both of the first surface and the second surface of the substrate layer is the surface having the largest area of ​​the substrate layer.

[0081] The thickness of the surface protective layer is preferably 1 μm or more, more preferably 5 μm or more. The thickness of the surface protective layer is preferably 50 μm or less, more preferably 30 μm or less. By making the thickness of the surface protective layer 1 μm or more, scratch resistance can be improved. Furthermore, by making the thickness of the surface protective layer 50 μm or less, the occurrence of defective appearance can be reduced.

[0082] The surface protection layer is formed by mixing the main component and curing agent of a two-component curing coating agent, applying the two-component curing coating agent to the first surface of the substrate layer, and heating the mixture. The main component and curing agent of the two-component curing coating agent are preferably mixed together immediately before applying the two-component curing coating agent to the substrate layer.

[0083] Examples of methods for applying the two-component curing coating agent to the substrate layer include application methods such as dip coating, spray coating, roll coating, doctor blade coating, and screen printing, and casting using a bar coater or applicator.

[0084] The two-component curing coating agent applied to the substrate layer is then thermally cured by heating, which causes the polyol and polyisocyanate contained in the two-component curing coating agent to react with each other to form polyurethane, thereby curing the two-component curing coating agent and forming a surface protective layer.

[0085] The heating temperature of the two-component curing coating agent is preferably 60 to 180° C., more preferably 80 to 150° C. The heating time of the two-component curing coating agent is preferably 1 to 30 minutes, more preferably 1 to 10 minutes.

[0086] [Adhesive layer] The multilayer film of the present invention preferably further comprises an adhesive layer laminated integrally on the second surface of the base layer, which allows the multilayer film to be easily attached to the surface of an article or the like.

[0087] The thickness of the adhesive layer is not particularly limited, but is preferably 10 to 200 μm, more preferably 20 to 100 μm.

[0088] The adhesive layer contains a pressure-sensitive adhesive. The pressure-sensitive adhesive is not particularly limited, and examples thereof include acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, vinyl alkyl ether pressure-sensitive adhesives, silicone pressure-sensitive adhesives, polyester pressure-sensitive adhesives, polyamide pressure-sensitive adhesives, polyurethane pressure-sensitive adhesives, fluorine-based pressure-sensitive adhesives, and epoxy pressure-sensitive adhesives, with acrylic pressure-sensitive adhesives being preferred. The pressure-sensitive adhesives may be used alone or in combination of two or more types.

[0089] Furthermore, the adhesive layer may contain additives as needed. Examples of additives include tackifiers such as rosin derivative resins, polyterpene resins, petroleum resins, and oil-soluble phenolic resins, plasticizers, fillers, antioxidants, antioxidants, and colorants such as pigments and dyes, including carbon black. The adhesive may also be crosslinked with a general-purpose crosslinking agent, such as an aziridine-based crosslinking agent, an epoxy-based crosslinking agent, or an isocyanate-based crosslinking agent.

[0090] The adhesive layer can be formed, without any particular limitation, by applying an adhesive composition containing an adhesive and, if necessary, an additive and a crosslinking agent to the second surface of the base layer and drying it, thereby forming an adhesive layer laminated and integrated with the second surface of the base layer.

[0091] (metallic glitter layer) The multilayer film of the present invention may further include a metallic bright layer. The metallic bright layer allows the multilayer film to exhibit brilliance, and the surface of an article such as an automobile can be decorated with a metallic look.

[0092] The metallic luster layer is not particularly limited, but may be disposed on at least one of the first and second surfaces of the substrate layer. If necessary, an anchor coat layer may be further disposed between the metallic luster layer and the layer adjacent to the metallic luster layer.

[0093] The metallic luminous layer preferably contains a metal. Examples of metals include copper, nickel, chromium, titanium, cobalt, molybdenum, zirconium, tungsten, palladium, indium, tin, gold, silver, and aluminum. Among these, indium and aluminum are preferred. These metals may be used alone or in combination of two or more. The thickness of the metallic luminous layer is preferably 1 nm to 100 nm, more preferably 1.5 nm to 7.5 nm.

[0094] The anchor coat layer is used to improve adhesion between the metal luminous layer and the layer adjacent to the metal luminous layer. The anchor coat layer preferably contains an anchor coat agent. Examples of anchor coat agents include polyester-based resins, melamine-based resins, urea-based resins, urea-melamine-based resins, urethane-based resins, acrylic resins, and nitrocellulose-based resins. These anchor coat agents may be used alone or in combination of two or more. The thickness of the anchor coat layer is not particularly limited and may be 0.01 to 1 μm.

[0095] The multilayer film of the present invention is preferably used to protect the surfaces of articles such as transportation equipment such as automobiles, trains, and airplanes, glass, buildings, and signs. That is, the multilayer film of the present invention is preferably used as a multilayer film for surface protection. For example, by adhering and integrating the multilayer film to the surface of an article with an adhesive or an adhesive layer, the surface of the article can be protected from dirt and scratches, and the appearance can be maintained for a long period of time.

[0096] In particular, the multilayer film of the present invention is suitable for use as a multilayer film for protecting the surface of an automobile. For example, the multilayer film can be attached to the painted surface of an automobile via an adhesive layer. This allows the automobile surface to be maintained in a beautiful condition for a long period of time.

[0097] The surface protective layer formed from the cured film of the two-component curing coating agent of the present invention is preferably used as the multilayer film described above, but the use of the surface protective layer is not limited to this form. For example, a surface protective layer can be formed on the surface of an article by directly applying the two-component curing coating agent to the surface of the article. Such a surface protective layer is laminated and integrated onto the surface of the article without an adhesive layer or substrate layer. This surface protective layer can also protect the surface of the article. The article is not particularly limited, and examples thereof include transportation equipment such as automobiles, trains, and airplanes, glass, buildings, and signs.

[0098] A method for forming a surface protective layer directly on the surface of an article using a two-component curing coating agent may be carried out in the same manner as the method for forming a surface protective layer described above for the multilayer film of the present invention, except that the two-component curing coating agent is applied directly to the surface of the article instead of to the first surface of the substrate layer. [Effects of the Invention]

[0099] The two-component curing coating agent of the present invention can provide a surface protective layer that is excellent in weather resistance, acid resistance, and stain resistance, thereby maintaining the beautiful appearance of the surface of an article to which the surface protective layer is applied for a long period of time.

[0100] Furthermore, the two-component curing coating agent of the present invention can provide a surface protective layer that is flexible and has excellent extensibility. Therefore, even when tension is applied to the surface protective layer, such as when the surface protective layer is attached to the surface of an article or when an article having the surface protective layer is molded, the surface protective layer can withstand the tension and can reduce the occurrence of cracks or breaks in the surface protective layer. DETAILED DESCRIPTION OF THE INVENTION

[0101] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples. [Example]

[0102] The following raw materials were used in the production of the two-component curing coating agents of the Examples and Comparative Examples. [Synthesis of acrylic polyol] (Synthesis Examples 1 to 7) A reaction vessel was charged with 233 parts by mass of methyl isobutyl ketone as a solvent and heated to 70°C. Next, a monomer composition containing 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, cyclohexyl methacrylate, n-butyl acrylate, and lauryl methacrylate in the amounts shown in Table 1 was stirred and mixed with azobis-2-methylbutyronitrile as a polymerization initiator in the amount shown in Table 1 to prepare a monomer mixture. The resulting monomer mixture was added dropwise to the solvent over 3 hours and polymerized for another 3 hours. This yielded an acrylic polyol solution (solid content 30% by mass) containing acrylic polyol.

[0103] Table 1 shows the hydroxyl value (mgKOH / g), glass transition temperature (° C.), and weight average molecular weight (Mw) of the acrylic polyols obtained in the synthesis examples.

[0104] [Polyester polyol] Polyester polyol (1) [Polyester polyol having an alicyclic structure (polycondensation product of adipic acid and a polyhydric alcohol having an alicyclic structure)]

[0105] [Polyisocyanate] Polyisocyanate (1) (a bifunctional polyurethane diisocyanate obtained by addition reaction of 1 mol of diol with 2 mol of hexamethylene diisocyanate, number of isocyanate groups per molecule: 2) Polyisocyanate (2) (biuret of hexamethylene diisocyanate, number of isocyanate groups per molecule: 3) Polyisocyanate (3) (Isocyanurate of hexamethylene diisocyanate, number of isocyanate groups per molecule: 3)

[0106] (Examples 1 to 11 and Comparative Examples 1 to 7) The acrylic polyols obtained in Synthesis Examples 1 to 7, cyclohexanedimethanol, 3-methyl-1,5-pentanediol, and polyester polyol (1) were fed into a reaction vessel in the amounts shown in Table 2, and then methyl isobutyl ketone was further fed. These were mixed to obtain a main component (solid content 30% by mass).

[0107] For the acrylic polyols obtained in Synthesis Examples 1 to 7, acrylic polyol solutions containing the acrylic polyols were supplied to a reaction vessel so that the blending amounts (solid content amounts) of each acrylic polyol were as shown in Table 2.

[0108] Next, polyisocyanates (1) to (3) were added to another reaction vessel in the amounts shown in Table 2, followed by methyl isobutyl ketone, and these were mixed to obtain a curing agent (solid content 30% by mass). This produced a two-component curing coating agent containing the base resin and the curing agent.

[0109] In the two-component curing coating agent, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group of the polyisocyanate contained in the curing agent to the hydroxyl group of the polyol contained in the base agent is shown in the "Equivalent ratio (isocyanate group / hydroxyl group)" column in Table 2.

[0110] Next, the curing agent was added to the base material and mixed. Immediately afterwards, the two-component curing coating agent was applied to the first surface of the substrate layer (thermoplastic polyurethane elastomer sheet, 150 μm thick) using a bar coater (No. 16). The applied two-component curing coating agent was heated at 120°C for 10 minutes to remove the solvent and thermally cure, forming a surface protection layer (10 μm thick) laminated and integrated on the first surface of the substrate layer.

[0111] Next, 100 parts by weight of an acrylic adhesive (manufactured by Harima Chemicals, product name "Haliakron 560CH") and 0.5 parts by weight of an isocyanate-based crosslinking agent were mixed to obtain a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition was then immediately applied to the second surface of the substrate layer using a bar coater (No. 24) to obtain a coating film. This coating film was heated at 100°C for 3 minutes to remove the solvent. After heating, a roller (weight 10 kg) wrapped with release paper was slowly rolled over the coating film to laminate the release paper onto the coating film. The coating film was then cured at 40°C for 3 days to form an adhesive layer (thickness 25 μm) on the second surface of the substrate layer. This resulted in a multilayer film comprising a substrate layer, a surface protective layer laminated and integrated with the first surface of the substrate layer, and an adhesive layer laminated and integrated with the second surface of the substrate layer.

[0112] [evaluation] The surface protective layers of the multilayer films obtained in the Examples and Comparative Examples were evaluated for acid resistance, weather resistance, elongation, and stain resistance according to the following procedures.

[0113] [Acid resistance] The multilayer film was cut to obtain a flat rectangular test piece measuring 20 mm in width and 70 mm in length. The release paper was peeled off from the test piece to expose the adhesive layer. The test piece was attached to the center of a flat rectangular glass plate (25 mm in width, 75 mm in length) using the adhesive layer to obtain a laminate. Next, the entire laminate was immersed in a sulfuric acid aqueous solution containing 60% by mass of sulfuric acid at a temperature of 50°C for 1 hour. The laminate was then removed from the sulfuric acid aqueous solution. The haze (H1) [%] of the laminate before immersion in the sulfuric acid aqueous solution and the haze (H2) [%] of the laminate after immersion in the sulfuric acid aqueous solution were measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product name "HAZE METER NDH 5000") in accordance with JIS K7136 (2000), and the haze change (%) was calculated according to the following formula. The calculated haze change was then evaluated according to the following criteria, and the results are shown in the "Acid Resistance" column in Table 2. Haze change (%) = H2 - H1

[0114] (Evaluation criteria for the amount of change in haze) A: The amount of change in haze was 0% or more and less than 2%. B: The amount of change in haze was 2% or more and less than 5%. C: The amount of change in haze was 5% or more and less than 10%. D: The amount of change in haze was 10% or more and less than 20%. E: The change in haze was 20% or more.

[0115] [Weather resistance] The appearance of the surface protective layer of the multilayer film before the accelerated weathering test was visually observed in accordance with JIS K5600-1.1, 4.4, "Appearance of coating film." The surface protective layer of the multilayer film obtained in each of the examples and comparative examples was colorless and transparent, with no irregularities formed on the surface.

[0116] Next, using an accelerated weathering tester (manufactured by Iwasaki Electric Co., Ltd., product name "Eye Super UV Tester: SUV-W161"), ultraviolet light was irradiated onto the surface of the surface protection layer of the multilayer film at an irradiance of 100 mW / cm under an atmosphere of temperature 63°C and relative humidity 70%. 2 After irradiating the multilayer film with UV light for 6 hours, the film was then left for 2 hours in an atmosphere at 50°C and 90% relative humidity without UV light. This cycle was repeated for 500 hours to conduct an accelerated weathering test. After the accelerated weathering test, the appearance of the surface protective layer of the multilayer film was visually observed in accordance with JIS K5600-1.1, 4.4, "Appearance of Coating Film," and evaluated according to the following criteria. The results are shown in the "Weatherability" column in Table 2.

[0117] (Evaluation criteria for the appearance of the surface protection layer after accelerated weathering test) A: No irregularities were formed on the surface of the surface protective layer, and no discoloration to white or yellow occurred on the surface protective layer. B: Concave and convex portions were formed in very small areas on the surface of the surface protective layer, but the surface protective layer did not discolor to white or yellow. C: Concave and convex portions were formed on many parts of the surface of the surface protective layer, and many parts of the surface protective layer were discolored white or yellow. D: Concave and convex portions were formed on the entire surface of the surface protective layer, and the surface protective layer was discolored to white or yellow overall.

[0118] [Extensibility] The multilayer film was cut into the shape of a "Type 5 test piece" as specified in JIS K7127, and the release paper was removed to obtain a test piece (25 mm wide, 115 mm long). The elongation of this test piece was measured using a tensile tester (Shimadzu Corporation, product name "Autograph AGS-X Precision Universal Testing Machine") in accordance with JIS K7127, "Plastics - Test Method for Tensile Properties." Specifically, the test piece was pulled at a tensile speed of 100 mm / min, a chuck distance of 80 mm, a gauge length of 50 mm, and a temperature of 23°C. The length L (mm) between the gauge lines of the test piece was measured when a crack appeared in the surface protective layer, and the elongation was calculated using the following formula. The calculated elongation was then evaluated according to the following criteria. The results are shown in the "Elongation" column of Table 2. Elongation rate (%) = 100 x (L-50) / 50

[0119] (Evaluation criteria for growth rate) A: The elongation rate was 85% or more. B: The elongation rate was 80% or more and less than 85%. C: The elongation rate was 75% or more and less than 80%. D: The elongation rate was less than 75%.

[0120] [Stain resistance] A line was drawn on the surface of the surface protective layer of the multilayer film using a commercially available oil-based pen (manufactured by ZEBRA, product name "Makie") and left for 1 minute. Next, 0.1 g of normal hexadecane was dropped onto the line drawn on the surface of the surface protective layer. The normal hexadecane adhering to the surface of the surface protective layer was then wiped off 10 times with a cellulose nonwoven fabric (manufactured by Asahi Kasei Corporation, product name "Bemcot M-3") under a load of 300 g. The appearance of the surface protective layer was then visually observed in accordance with JIS K5600-1.1, 4.4, "Appearance of Coating Film," and evaluated according to the following criteria. The results are shown in the "Anti-fouling" column of Table 2.

[0121] (Evaluation criteria for the appearance of the surface protection layer after wiping) A: All lines drawn on the surface of the surface protective layer could be wiped off and were no longer visible. B: The line drawn on the surface of the surface protection layer appeared extremely faint. C: The line drawn on the surface of the surface protective layer appeared faint. D: The lines drawn on the surface of the surface protective layer appeared dark.

[0122] [Table 1] TIFF0007740884000002.tif211153

[0123] [Table 2] TIFF0007740884000003.tif233153 [Industrial Applicability]

[0124] According to the present invention, a two-component curing coating agent can be provided that can form a surface protective layer that is excellent in weather resistance, acid resistance, stain resistance, and elongation. The surface protective layer formed from a cured film of the two-component curing coating agent can protect the surface of an article from stains and scratches, and maintain an excellent appearance.

Claims

1. A two-component curing coating agent characterized by comprising: a base material containing an acrylic polyol having a hydroxyl value of 36 mgKOH / g or more and 125 mgKOH / g or less and containing an alicyclic structure; and a polyol containing an alkyl polyol formed by substituting at least two hydrogen atoms in one molecule of a saturated hydrocarbon having a chain or saturated alicyclic structure with hydroxyl groups; and a curing agent containing polyisocyanate.

2. 2. The two-component curing coating agent according to claim 1, wherein the content of the acrylic polyol in the polyol is 35 parts by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the total amount of the acrylic polyol and the alkyl polyol.

3. A two-component curing coating agent as described in claim 1 or claim 2, characterized in that the content of alkyl polyol in the polyol is 10 parts by mass or more and 65 parts by mass or less per 100 parts by mass of the total amount of acrylic polyol and alkyl polyol.

4. 4. The two-component curing coating agent according to claim 1, wherein the alkyl polyol comprises a cycloalkyl polyol.

5. 5. The two-component curing coating agent according to claim 1, wherein the polyisocyanate has three or more isocyanate groups in one molecule.

6. The two-component curing coating agent according to any one of claims 1 to 5, wherein the polyisocyanate contains an isocyanurate of polyisocyanate.

7. A multilayer film comprising a substrate layer and a surface protective layer which is laminated integrally on a first surface of the substrate layer and is a cured film of the two-component curing coating agent according to any one of claims 1 to 6.

8. 7. The multilayer film according to claim 6, further comprising an adhesive layer laminated and integrated onto the second surface of the base layer.

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