Polyurethane resin composition

Abstract

To provide a polyurethane resin composition that can form a coating layer having high adhesion to various materials and high elongation (elasticity / flexibility).SOLUTION: A polyurethane resin composition contains (A) a polyester polyol that is a condensation reactant of aromatic dicarboxylic acid, aliphatic dicarboxylic acid and aliphatic diol, and (B) a polyisocyanate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyurethane resin composition using a polyester polyol. [Background technology]

[0002] When painting substrates, it is common to use a paint that is optimal for the substrate material, such as inorganic materials like metal, glass, and cement, or organic materials like plastic. However, this method requires two or more types of paint when painting composite materials that combine different materials, making the painting process complicated. Therefore, there is a potential market need for painting with a single paint. To meet this need, there is a demand for paints that not only have high adhesion to a variety of materials, but also adhere to highly elastic substrates like natural rubber and easily deformable substrates like foam materials and fabric, and can follow deformations such as stretching and bending.

[0003] Two-component polyurethane paints have been used in applications requiring high strength, such as automobile repair, due to the toughness of the paint film. However, the paint film lacks flexibility, which contradicts its toughness, making it difficult to use on substrates that are prone to deformation.

[0004] Patent Document 1 discloses that when a polyurethane elastomer obtained by reacting a polyester polyol having an aromatic skeleton, a diol having an aliphatic skeleton, and a diisocyanate is used in fibers, the elasticity of the polyurethane elastomer provides a comfortable wearing feel. However, it does not disclose the application of this elastomer to coatings.

[0005] On the other hand, Patent Document 2 discloses a coating film obtained from a resin composition containing an acrylic polyol and a diisocyanate. However, the flexibility (impact resistance) is insufficient, and there are concerns about poor adhesion due to the low tackiness of the coating film surface. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-81305 [Patent Document 2] Japanese Patent Application Publication No. 09-059566 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a polyurethane resin composition that can form a coating film having high adhesion to various materials and elongation (elasticity and flexibility). [Means for solving the problem]

[0008] As a result of extensive research to solve the above problems, the inventors discovered that by combining aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and aliphatic diols as raw material components of polyester polyols, it is possible to achieve both adhesion to various materials and elongation (elasticity and flexibility), and thus completed the present invention.

[0009] That is, the present invention relates to a polyurethane resin composition containing (A) a polyester polyol which is a condensation reaction product of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol, and (B) a polyisocyanate.

[0010] The aliphatic diol preferably has an aliphatic skeleton having 2 to 6 carbon atoms.

[0011] The aromatic dicarboxylic acid is preferably selected from the group consisting of o-phthalic acid, m-phthalic acid and p-phthalic acid.

[0012] The (B) polyisocyanate is preferably an adduct of an aliphatic diisocyanate having 6 or more carbon atoms and an aliphatic polyol.

[0013] It is preferable that the polyurethane resin composition further contains (C) a silicone compound having a reactive hydroxyl group.

[0014] The present invention also relates to a polyurethane coating material containing the polyurethane resin composition of the present invention.

[0015] The present invention also relates to a coating film comprising a cured product of the polyurethane resin composition or polyurethane coating material of the present invention.

[0016] When the coating film has a thickness of 50 μm, it preferably exhibits an elongation rate of 300% or more.

[0017] The present invention also relates to a laminate having the coating film of the present invention on a substrate. [Effects of the Invention]

[0018] By using the polyurethane resin composition of the present invention, it is possible to obtain a coating film that has high adhesion to various materials and high elongation (elasticity and flexibility). [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram of the substrate and coating film used in Examples 9 to 14. DETAILED DESCRIPTION OF THE INVENTION

[0020] The polyurethane resin composition of the present invention contains (A) a polyester polyol which is a condensation reaction product of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol, and (B) a polyisocyanate.

[0021] <(A) Polyester polyol> The polyester polyol (A) used in the present invention is a condensation reaction product of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol.

[0022] The aromatic dicarboxylic acid is not particularly limited, and examples thereof include o-phthalic acid (orthophthalic acid), m-phthalic acid (isophthalic acid), p-phthalic acid (terephthalic acid), naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and reactive derivatives thereof such as acid anhydrides, alkyl esters, and acid halides. Among these, from the viewpoints of ease of availability as a raw material and cost, aromatic dicarboxylic acids having 8 to 14 carbon atoms and their reactive derivatives are preferred, and o-phthalic acid, m-phthalic acid, p-phthalic acid, and their reactive derivatives are particularly preferred. These dicarboxylic acids can be used alone or in combination of two or more.

[0023] The aliphatic dicarboxylic acid is not particularly limited, and examples thereof include linear, branched, or cyclic aliphatic dicarboxylic acids and their reactive derivatives such as acid anhydrides, alkyl esters, and acid halides. Specific examples include succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, maleic acid, fumaric acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and cyclopentanedicarboxylic acid. Among these, from the viewpoints of ease of availability as a raw material and cost, aliphatic dicarboxylic acids having 4 to 9 carbon atoms and their reactive derivatives are preferred, and linear aliphatic dicarboxylic acids and their reactive derivatives are more preferred, with adipic acid and its reactive derivatives being particularly preferred. These dicarboxylic acids can be used alone or in combination of two or more.

[0024] The ratio of aromatic dicarboxylic acid to aliphatic dicarboxylic acid is preferably 20 to 80 weight percent, more preferably 30 to 70 weight percent, of a total of 100 parts by weight of aromatic dicarboxylic acid and aliphatic dicarboxylic acid. If it is less than 20 weight percent, adhesion to the substrate tends to decrease, and if it exceeds 80 weight percent, the elasticity and flexibility of the coating film tends to decrease.

[0025] The aliphatic diol is not particularly limited, and examples thereof include linear (ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, etc.), branched (1,2-propanediol (propylene glycol), neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, etc.) and cyclic (1,4-bis(hydroxymethyl)cyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane) aliphatic diols. These diols can be used alone or in combination of two or more. Among these, from the viewpoints of ease of availability as a raw material and cost, those having 2 to 8 carbon atoms are preferred, and those having 2 to 6 carbon atoms are more preferred.

[0026] As the diol component, an aliphatic diol and an aromatic diol may be used in combination, but the proportion of the aliphatic diol in the total diol components is preferably 60 to 100% by weight, more preferably 70 to 100% by weight, and even more preferably 80 to 100% by weight. If it is less than 60% by weight, the elasticity and flexibility of the coating film tend to decrease.

[0027] The number average molecular weight (Mn) of the (A) polyester polyol is preferably 1,000 to 30,000, more preferably 10,000 to 20,000. If it is less than 1,000, elasticity tends to decrease, and if it exceeds 30,000, viscosity tends to increase, significantly decreasing handleability. The number average molecular weight can be determined in terms of polystyrene using gel permeation chromatography (GPC).

[0028] The weight-average molecular weight (Mw) of the (A) polyester polyol is preferably 2000 to 60000, more preferably 20000 to 40000. If it is less than 2000, elasticity tends to decrease, and if it exceeds 60000, viscosity tends to increase, significantly decreasing handleability. The weight-average molecular weight can be determined in terms of polystyrene using GPC.

[0029] The hydroxyl value of the (A) polyester polyol is preferably 5 to 100 mgKOH / g, more preferably 5 to 50 mgKOH / g. If it is less than 5 mgKOH / g, the crosslinking density will decrease, which will tend to reduce the film strength. If it exceeds 100 mgKOH / g, the water resistance of the film will tend to decrease. The hydroxyl value can be determined by esterifying the polyester polyol with a pyridine solution of phthalic anhydride and titrating the excess phthalic anhydride with a sodium hydroxide solution (in accordance with JIS K 1557-1).

[0030] The polyester polyol (A) can be obtained by dehydration condensation of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol by a known method.

[0031] The ratio of the dicarboxylic acid components (aromatic dicarboxylic acid and aliphatic dicarboxylic acid) to the diol component is preferably such that the ratio of the total number of moles of hydroxyl groups contained in the diol component to the total number of moles of carboxyl groups contained in the dicarboxylic acid (hydroxyl groups / carboxy groups) is 0.5 to 1.5, more preferably 0.8 to 1.2.

[0032] <(B) Polyisocyanate> The polyisocyanate (B) used in the present invention is not particularly limited, and examples thereof include linear, branched, or cyclic aliphatic polyisocyanates and aromatic polyisocyanates. Examples of aliphatic polyisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Examples of aromatic diisocyanates include toluene diisocyanate, naphthylene diisocyanate, and xylylene diisocyanate. Adducts obtained by addition reaction of these polyisocyanates with polyols such as glycerin and trimethylolpropane can also be used. These polyisocyanates can be used alone or in combination of two or more.

[0033] Among these, those having an aliphatic skeleton (aliphatic polyisocyanates and adducts of aliphatic polyisocyanates and aliphatic polyols) are preferred because they provide coating films with high elasticity and flexibility. Furthermore, from the standpoints of ease of availability as raw materials and cost, adducts of aliphatic diisocyanates having 6 or more carbon atoms, preferably 6 to 12 carbon atoms, such as hexamethylene diisocyanate, and aliphatic polyols are more preferred, and adducts of hexamethylene diisocyanate and trimethylolpropane are particularly preferred.

[0034] Polyisocyanates having an aliphatic skeleton and polyisocyanates having an aromatic skeleton may be used in combination, but the proportion of polyisocyanates having an aliphatic skeleton in the total polyisocyanate components is preferably 50 to 100% by weight, more preferably 70 to 100% by weight or more, and even more preferably 80 to 100% by weight or more. If it is less than 50% by weight, the elasticity and flexibility of the coating film tend to decrease.

[0035] NCO%, which indicates the weight percentage of NCO groups in the polyisocyanate, is preferably 2 to 30%, and more preferably 2 to 20%.

[0036] <(C) Silicone Compound Having a Reactive Hydroxyl Group> The polyurethane resin composition of the present invention preferably further contains (C) a silicone compound having a reactive hydroxyl group. The "reactive hydroxyl group" refers to a hydroxyl group that is reactive with an isocyanate group. Because the silicone compound that acts as a slip agent has a reactive hydroxyl group, it reacts with the polyisocyanate and is fixed in the cured coating film, allowing the slip property to be maintained for a long period of time.

[0037] In the silicone compound (C) having a reactive hydroxyl group, the reactive hydroxyl group may or may not be directly bonded to Si. The reactive hydroxyl group may also be generated by hydrolysis of an alkoxysilyl group or the like. The silicone compound (C) having a reactive hydroxyl group may have, in addition to the reactive hydroxyl group, a reactive group such as a (meth)acrylic group, a vinyl group, an amino group, or an epoxy group, or a non-reactive group such as an alkyl group, an ester group, an aralkyl group, a phenyl group, or a polyether group.

[0038] The number average molecular weight of the (C) silicone compound having a reactive hydroxyl group is preferably 1000 to 20000, more preferably 3000 to 15000. If it is less than 1000, it will tend to separate from the film and the effect will not last, and if it exceeds 20000, it will be difficult to orient it on the film surface, and the anti-tack effect will tend not to be achieved.

[0039] The weight-average molecular weight of the (C) silicone compound having a reactive hydroxyl group is preferably 2000 to 40000, more preferably 6000 to 30000. If it is less than 2000, it will tend to separate from the film and the effect will not last, and if it exceeds 40000, it will be difficult to orient it on the film surface, and the anti-tack effect will tend not to be achieved.

[0040] The hydroxyl value of the silicone compound (C) having a reactive hydroxyl group is preferably 30 to 200 mgKOH / g, more preferably 80 to 150 mgKOH / g. If it is less than 30 mgKOH / g, it tends to separate from the film and its effect will not last, while if it exceeds 200 mgKOH / g, its water solubility increases and it tends to separate from the film due to moisture.

[0041] <Other additives> Various additives such as pigments, dispersants, solvents, leveling agents, curing catalysts, thickeners, ultraviolet absorbers, light stabilizers, antioxidants, and silane coupling agents may be added to the polyurethane resin composition of the present invention as needed.

[0042] The pigment is not particularly limited. Examples of coloring pigments include titanium oxide, iron oxide-based yellow and red pigments, carbon black, phthalocyanine blue, phthalocyanine green, benzimidazolone, quinacrindone, anthraquinone, naphthol, and various azo-based pigments. These pigments can be used alone or in combination depending on the desired color. Examples of extender pigments include calcium carbonate, talc, clay, alumina white, barium sulfate, basic magnesium carbonate, baryte powder, diatomaceous earth, and silica. Examples of rust-preventive pigments include lead cyanamide, lead suboxide, zinc chromate, strontium chromate, and zinc oxide. The blending amount is also not particularly limited. For example, 1 to 300 parts by weight can be added per 100 parts by weight of (A) polyester polyol.

[0043] The dispersant is not particularly limited, and examples thereof include polycarboxylic acid-based pigment dispersants, polyamine-based pigment dispersants, etc. The blending amount is also not particularly limited, and for example, 0.1 to 10 parts by weight can be added per 100 parts by weight of (A) polyester polyol.

[0044] The solvent is not particularly limited, and examples thereof include cyclohexanone, butyl acetate, ethyl acetate, xylene, toluene, methyl isobutyl ketone, and methyl ethyl ketone. These solvents can be used alone or in combination of two or more. The content of the solvent in the resin composition is also not particularly limited, and can be adjusted as needed.

[0045] The leveling agent is not particularly limited, and examples thereof include polyether-based leveling agents, fluorine-based leveling agents, polyester-based leveling agents, siloxane-based leveling agents, silicone-based leveling agents, acrylic-based leveling agents, etc. The amount of the leveling agent to be added is not particularly limited, but is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, per 100 parts by weight of (A) polyester polyol.

[0046] The silane coupling agent is not particularly limited, and examples thereof include vinyl-based silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane, (meth)acrylic-based silane coupling agents such as γ-methacryloxypropyltrimethoxysilane, epoxy-based silane coupling agents such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and amine-based silane coupling agents such as γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane. The amount of the silane coupling agent to be added is not particularly limited, but is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the (A) polyester polyol.

[0047] <Polyurethane resin composition> The method for producing the polyurethane resin composition of the present invention is not particularly limited. The polyurethane resin composition may be either a one-component type or a two-component type, but is preferably a two-component type from the viewpoint of ensuring the toughness of the film.

[0048] The blending ratio of the components is preferably such that the ratio of the total number of moles of isocyanate groups contained in (B) polyisocyanate to the total number of moles of hydroxyl groups contained in (A) polyester polyol and (C) silicone compound having a reactive hydroxyl group (isocyanate groups / hydroxyl groups) is 0.7 to 1.5, and more preferably 0.8 to 1.2.

[0049] The amount of (C) silicone compound having a reactive hydroxyl group is preferably 0.3 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of (A) polyester polyol. If it is less than 0.3 parts by weight, the surface tackiness of the coating film may not be sufficiently suppressed, while if it exceeds 10 parts by weight, the water resistance may decrease and the coating film surface may whiten in a humid environment.

[0050] The polyurethane resin composition of the present invention can be suitably used as a coating material for clothing such as underwear, sportswear, stockings, socks, and supports, and as a coating material for medical supplies such as bandages, gauze, and adhesive plasters. The polyurethane resin composition of the present invention can also be suitably used as a coating material for forming a transparent coating film.

[0051] The polyurethane resin composition of the present invention can also be suitably used as a chipping-resistant primer for preventing scratches and corrosion caused by flying stones, etc., in the underside of an automobile body panel or bumper. In this case, the chipping-resistant primer layer can be formed on a substrate such as the underside of an automobile body panel or bumper, or under an intermediate coat layer. A metallic base layer, an intermediate coat layer, a clear coat layer, etc. may be further laminated on the chipping-resistant primer layer in any order.

[0052] The polyurethane resin composition of the present invention can also be used for bonding polarizing filters, color filters, electrode substrates, etc. in flexible display devices and flexible touch panels. It can also be used as an adhesive for transparent substrates for producing laminated glass for automobiles, aircraft, ships, buildings, etc.

[0053] <Coating film> The coating film of the present invention comprises a cured product of the polyurethane resin composition or polyurethane coating material of the present invention.

[0054] The method for applying the polyurethane resin composition or polyurethane coating material to a substrate is not particularly limited, and examples thereof include brushing, roller coating, bar coating, spin coating, dipping, spraying, printing, inkjet coating, etc. The curing method is also not particularly limited, and examples thereof include known methods such as curing by drying at room temperature and accelerated curing by heating.

[0055] The thickness of the coating film is not particularly limited, but is preferably 5 to 200 μm. If the thickness is less than 5 μm, the film strength is insufficient and the film tends to break, while if it exceeds 200 μm, the reactivity tends to become non-uniform and the feel to the touch tends to be poor. If a thickness exceeding 200 μm is required, the coating and curing process can be repeated several times.

[0056] The coating film of the present invention preferably exhibits an elongation of 300% or more, more preferably 350% or more, when the film thickness is 50 μm, where the elongation is a value measured by a tensile test on a free film.

[0057] <Transparent coating film and transparent laminate> The coating film of the present invention can be a transparent coating film that has transparency in addition to adhesion and stretchability. The total light transmittance of the transparent coating film alone is preferably 90% or more, more preferably 93% or more, and even more preferably 95% or more. The total light transmittance can be evaluated by the total light transmittance test of JIS K 7375 using a visible light transmittance meter.

[0058] By using a transparent material as the substrate, high transparency can be imparted to the entire laminate consisting of the substrate and the coating film. The material of the transparent substrate is not particularly limited, and examples thereof include resin, rubber, and glass. Examples of resins include electrostatically processed polypropylene, polycarbonate resin, nylon 6, polyethylene terephthalate resin, acrylic resin, polyurethane resin, polyester resin, ABS resin, hard vinyl chloride, soft vinyl chloride, vinyl acetate resin, and polystyrene. Examples of rubber include butyl rubber, urethane rubber, and silicone rubber. Examples of glass include heat-absorbing glass, heat-reflecting glass, green glass, lined plate glass, and colored glass. The transparent substrate may also be a composite material combining two or more of these materials. The shape of the substrate is also not particularly limited, and examples include flat, curved, and spherical surfaces. Furthermore, the first transparent substrate and the second transparent substrate may be the same or different.

[0059] The transparent laminate preferably has a total light transmittance of 75% or more, more preferably 80% or more, even more preferably 90% or more, and particularly preferably 95% or more.

[0060] The haze of the transparent coating film alone is preferably 1% or less, more preferably 0.5% or less. The haze of the transparent laminate is preferably 5% or less, more preferably 2% or less. The haze can be measured and calculated using a visible light transmittance measuring device.

[0061] The refractive index of the transparent coating film can be appropriately set depending on the application of the laminate, and can be, for example, 1.2 to 1.7 at a wavelength of 550 nm.

[0062] <Laminate> The laminate of the present invention is characterized by having the coating film of the present invention on a substrate.

[0063] The material of the substrate is not particularly limited, and examples thereof include natural rubber, synthetic rubber (styrene-butadiene rubber, nitrile rubber, butyl rubber, urethane rubber, chloroprene rubber, ethylene-propylene rubber, silicone rubber, etc.), metal (iron, stainless steel (SUS304, SUS430, etc.), aluminum (aluminum 5052, aluminum 6063, etc.), copper, brass, etc.), resin (polyethylene, polypropylene, electrostatically treated polypropylene, polycarbonate resin, nylon 6, nylon 66, PET resin, acrylic resin, polyurethane resin, polyester resin, polyacetal resin, ABS resin, hard vinyl chloride, soft vinyl chloride, vinyl acetate resin, etc.), glass, ceramics, tile, concrete, woven fabric, nonwoven fabric, synthetic leather, and natural leather (cowhide, etc.). The fibers constituting the woven fabric and nonwoven fabric may be the resins described above, cotton, silk, etc. These may be used alone or in composite materials combining two or more types.

[0064] The form of the substrate is not particularly limited, and examples thereof include a film, a sheet, a molded product, an expanded type, and a foam type. [Example]

[0065] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Furthermore, unless otherwise specified, "parts" means parts by weight.

[0066] (1) Various chemicals used in the examples and comparative examples Silicone compound 1: KR-500 (a silicone compound having a methoxysilyl group. Contains 28% by weight of methoxy groups), manufactured by Shin-Etsu Chemical Co., Ltd. Silicone compound 2: BYK-330 (BYK) Silane coupling agent: BYK-4512 (BYK) Adduct of hexamethylene diisocyanate and trimethylolpropane: Duranate E402-90T (NCO%: 8.5%) manufactured by Asahi Kasei Corporation Adduct of m-xylene diisocyanate and trimethylolpropane: Desmodur L75 (NCO%: 13.3%), manufactured by Sumika Covestro Urethane Co., Ltd. Titanium oxide: JR-901 (manufactured by Teika Co., Ltd.) Dispersant: BYK-161 (BYK)

[0067] (2) The prepared resin compositions were evaluated by the following methods.

[0068] <Adhesion> The resin composition was applied to various substrates listed in Table 1, and then dried to obtain a 15 μm-thick coating film. 1 mm square grid-like cuts were made in the film with a cutter knife, and adhesive tape was then applied and peeled off to check the proportion of the film remaining on the substrate, and the adhesion was evaluated on the following 7-point scale (based on the JIS K 5600-5-6 cross-cut test method). 6: The coating film adhered to the substrate and no peeling occurred. 5: The coating peeled off in the range of more than 0% to 5%. 4: More than 5% but not more than 15% of the coating peeled off. 3: More than 15% but not more than 35% of the coating peeled off. 2: More than 35% but not more than 65% of the coating peeled off. 1: More than 65% of the coating peeled off. However, the coating did not peel off when peeled off only with adhesive tape without making a cross-cut incision. 0: More than 65% of the coating peeled off. Furthermore, the coating peeled off simply by attaching and peeling off adhesive tape without making cross-cut cuts.

[0069] <Growth rate> The resin composition was applied to a natural rubber substrate to form a coating film with a thickness of 50 μm, and both ends were tensile-deformed to measure the elongation of the coating film. The elongation (%) is expressed as the ratio of the length of the substrate at the time when the coating film is stretched to the length before stretching.

[0070] <Surface adhesiveness (tackiness)> The surface of the coating film formed on the natural rubber substrate was touched with a hand to evaluate the feel. ×: There was a tacky feeling. △: There was little tacky feeling, and it was the same as a general paint. ◯: There was almost no tacky feeling, and it felt smooth to the touch. ⊚: There was no tacky feeling, and it felt smooth to the touch.

[0071] (3) Evaluation of adhesion and elongation rate 1 Example 1 A dicarboxylic acid mixture was obtained by mixing 14 parts of aromatic dicarboxylic acids, terephthalic acid and 14 parts of isophthalic acid, with 30 parts of adipic acid, an aliphatic dicarboxylic acid. This mixture was then mixed with 8 parts of aliphatic diols, ethylene glycol, 17 parts of neopentyl glycol, and 17 parts of 1,6-hexanediol, and subjected to a condensation reaction by a known method to obtain polyester polyol (A1). The Mn of (A1) was 17,400, the Mw was 34,100, and the hydroxyl value (solid) was 10 mgKOH / g. 100 parts of the obtained (A1) were mixed with 1 part of a silicone compound and then with 100 parts of cyclohexanone as a solvent to form a base resin. 4 parts of an adduct of hexamethylene diisocyanate and trimethylolpropane were added as a curing agent to obtain a resin composition. The evaluation results for adhesion, elongation, and surface tackiness are shown in Table 1.

[0072] Example 2 A resin composition was obtained in the same manner as in Example 1, except that bisphenol A, an aromatic diol, was used instead of 1,6-hexanediol. The evaluation results of adhesion, elongation and surface tackiness are shown in Table 1.

[0073] Example 3 A resin composition was obtained in the same manner as in Example 1, except that an adduct of hexamethylene diisocyanate and trimethylolpropane was not used, and instead 5 parts of an adduct of m-xylene diisocyanate having an aromatic skeleton and trimethylolpropane was blended. The evaluation results of adhesion, elongation and surface tackiness are shown in Table 1.

[0074] Example 4 Except for not using the silicone compound, a resin composition was obtained in the same manner as in Example 1. The evaluation results of adhesion, elongation and surface tackiness are shown in Table 1.

[0075] Comparative Example 1 A resin composition was obtained in the same manner as in Example 1, except that 29 parts of terephthalic acid and 29 parts of isophthalic acid were used as the dicarboxylic acids. The evaluation results of adhesion, elongation and surface tackiness are shown in Table 1.

[0076] [Table 1]

[0077] As shown in Table 1, each example in which an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol were combined as raw material components for the polyester polyol showed higher adhesion and elongation than Comparative Example 1, which did not use an aliphatic dicarboxylic acid.

[0078] (4) Evaluation of adhesion and elongation rate 2 Example 5 A dicarboxylic acid mixture containing 14 parts terephthalic acid, 14 parts isophthalic acid, and 30 parts adipic acid was mixed with 11 parts neopentyl glycol, 17 parts 1,6-hexanediol, and 10 parts propylene glycol, and the mixture was subjected to a condensation reaction to obtain a polyester polyol (Mn: 10,000, Mw: 20,000, hydroxyl value (solid): 20 mg KOH / g). This polyester polyol was mixed with 1 part silicone compound and 100 parts cyclohexanone to form a base resin. Four parts of an adduct of hexamethylene diisocyanate and trimethylolpropane were then added as a curing agent to obtain a resin composition. The evaluation results of adhesion, elongation and surface tackiness are shown in Table 2.

[0079] Example 6 15 parts of titanium oxide, 1 part of dispersant, 10 parts of the polyester polyol (A1) obtained in Example 1, and 10 parts of cyclohexanone were blended and dispersed and mixed for 30 minutes using a paint shaker to obtain 36 parts of a dispersion paste. 40 parts of the polyester polyol (A1) obtained in Example 1, 1 part of a silicone compound, and 23 parts of cyclohexanone were mixed with this dispersion paste to obtain a base resin. 67 parts of cyclohexanone and 4 parts of an adduct of hexamethylene diisocyanate and trimethylolpropane as a curing agent were then mixed with this to obtain a resin composition. The evaluation results of adhesion, elongation and surface tackiness are shown in Table 2.

[0080] [Table 2]

[0081] As shown in Table 2, Example 6, in which a pigment component was mixed, also showed a high elongation rate.

[0082] Example 7 A resin composition was obtained in the same manner as in Example 5, except that 2 parts of a silane coupling agent was further added to the formulation of Example 5. The evaluation results of adhesion, elongation and surface tackiness are shown in Table 3.

[0083] Example 8 A resin composition was obtained in the same manner as in Example 5, except that in the formulation of Example 5, 20 parts of silicone compound 1 was used, and further 0.5 parts of silicone compound 2 and 2 parts of a silane coupling agent were added. The evaluation results of adhesion, elongation and surface tackiness are shown in Table 3.

[0084] [Table 3]

[0085] In Example 7, the adhesion to poorly adherent substrates such as chloroprene rubber, polyethylene, polypropylene, and 66 nylon was improved.

[0086] In Example 8, silicone compound 2 was added as a leveling agent to improve wetting and spreading, and the adhesion to poorly adherent substrates was improved as in Example 7. Furthermore, the surface tackiness was further improved by increasing the content of silicone compound 1.

[0087] (5) Elasticity and transparency evaluation of resin composition films Examples 9 to 14 The resin compositions of Examples 1 to 4 and 7 to 8 were each applied to a 0.1 mm thick acrylic resin substrate and then dried to obtain a 15 μm thick coating film. A schematic diagram of the substrate and coating film is shown in Figure 1. The modulus, load strain, haze, and total light transmittance of this coating film were measured using a texture analyzer TA.XTplus (Eiko Seiki). The evaluation results are shown in Table 4.

[0088] [Table 4]

[0089] As shown in Table 4, the adhesive layers made of the compositions of Examples 1 to 4 and 7 to 8 exhibited low haze values ​​of 0.5% or less and high total light transmittances of 93% or more.

[0090] (6) Transparency evaluation on glass substrate Example 15 The resin composition of Example 1 was spin-coated onto an alkali-free glass substrate (EagleXE, Corning Incorporated) to form a film. After film formation, the film was dried to obtain a coating film with a thickness of 15 μm. The total light transmittance, haze, YI (yellow index), n (refractive index) at a wavelength of 550 nm, and k (extinction coefficient) of the laminate including this coating film and substrate were measured using an ellipsometer. The evaluation results are shown in Table 5.

[0091] Examples 16 to 18 The resin compositions of Examples 4, 7, and 8 were spin-coated onto alkali-free glass substrates (EagleXE, Corning Inc.) to form films. After film formation, the films were dried to obtain coatings with a thickness of 15 μm. The laminates including the coatings and the substrates were evaluated in the same manner as in Example 15. The results are shown in Table 5.

[0092] Comparative Example 2 The total light transmittance, haze, YI (yellow index), n (refractive index) and k (extinction coefficient) at a wavelength of 550 nm of the alkali-free glass substrate (EagleXE, Corning Inc.) used in Examples 15 to 18 were measured using an ellipsometer. The evaluation results are shown in Table 5.

[0093] [Table 5]

[0094] As shown in Table 5, the resin compositions of Examples 1, 4, 7, and 8 exhibited high total light transmittance and low haze values ​​even when coated on a glass substrate. They also exhibited sufficient values ​​for the yellow index (YI), refractive index, and extinction coefficient, which are important performance factors for laminates using glass as a substrate.

[0095] (7) Flexibility evaluation Each of the resin compositions of Examples 1, 4, 7, and 8 was applied to a 0.3 mm thick metal substrate and then dried to obtain a laminate having a 15 μm thick coating film on the substrate. The flexibility of this laminate was evaluated using the flex test of JIS K 5600-5-1. As a result, each of the laminates made from the resin compositions of Examples 1, 4, 7, and 8 did not experience cracking or peeling of the coating film when tested using a 2 mm diameter mandrel using the 3.1.2 Type 1 testing device in JIS Part 5: Mechanical Properties of Coating Films, Section 1: Flex Resistance (Cylindrical Mandrel Method). [Industrial Applicability]

[0096] The polyurethane resin composition and polyurethane coating of the present invention provide cured coating films that exhibit high adhesion to various substrates and high elasticity and flexibility that allow them to adapt to the expansion and contraction of the substrate, making them suitable for use on composite materials that combine two or more materials. For example, a single coating can be used to coat automobile tires that combine rubber and metal materials, or composite sections of highways (combinations of rubber cushioning materials used at the joints between roads and bridges, and steel and concrete sections of bridges), thereby meeting market needs and simplifying construction work. Furthermore, taking advantage of their adhesion, elasticity, and flexibility, the compositions can be used as chip-resistant primers for automobiles, adhesives for polarizing filters, color filters, electrode substrates, and other applications, as well as adhesives for transparent substrates in the production of laminated automotive glass.

Claims

1. (A) a polyester polyol which is a condensation reaction product of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol, in which the aromatic dicarboxylic acid accounts for 20 to 80% by weight of the total amount of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid; (B) a polyisocyanate which is an adduct of an aliphatic diisocyanate having 6 or more carbon atoms and an aliphatic polyol, and (C) Silicone compound having a reactive hydroxyl group A polyurethane resin composition comprising:

2. 2. The polyurethane resin composition according to claim 1, wherein the aliphatic diol has an aliphatic skeleton having 2 to 6 carbon atoms.

3. 3. The polyurethane resin composition according to claim 1, wherein the aromatic dicarboxylic acid is selected from the group consisting of o-phthalic acid, m-phthalic acid, and p-phthalic acid.

4. A polyurethane paint comprising the polyurethane resin composition according to any one of claims 1 to 3.

5. A coating film comprising a cured product of the polyurethane resin composition according to any one of claims 1 to 3 or the polyurethane coating material according to claim 4.

6. 6. The coating film according to claim 5, which exhibits an elongation rate of 300% or more when the coating film has a thickness of 50 μm.

7. A laminate having the coating film according to claim 5 or 6 on a substrate.

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