Polyurethane resin composition

Abstract

To provide a polyurethane resin composition which enables formation of a cured film having high adhesion to various materials and elongation, and is excellent in storage stability.SOLUTION: A polyurethane resin composition contains (A) a polyester polyol, which is a condensation reaction product of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid and an aliphatic diol, (B) a polyisocyanate and (C) a hydrocarbon compound having a reactive thiol group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyurethane resin composition comprising a hydrocarbon compound having a reactive thiol group. Background Art

[0002] In the coating of substrates, it is common to use a coating material that is optimal for the substrate material, such as inorganic materials like metals, glass and cement, or organic materials like plastics. However, this method requires two or more types of coating materials when coating a composite material combining different materials. There is a potential demand for coating composite materials with a single coating material. To meet this demand, coating materials having high adhesion to various materials are required. Furthermore, there is a demand for coating materials that can adhere to highly elastic substrates such as natural rubber, and easily deformable substrates such as foam materials and fabrics, and can follow deformations such as stretching and bending.

[0003] In addition, polyurethane resin compositions are widely used as coating materials. In particular, a polyurethane composition containing a polyol with a large molecular weight can form a strong cured product, but it is inferior in storage stability, so it needs to be a two-component type and has poor workability. It also has low fluidity and is not suitable for coating materials. A polyurethane composition containing a low-molecular-weight polyol has improved storage stability and can be made into a one-component type, but the physical properties of the cured product are insufficient.

[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 for fibers, a comfortable wearing feeling can be obtained due to its elastic function. However, the application of this elastomer to coating is not disclosed.

[0005] 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 is concern that the adhesion is low due to the low adhesiveness of the coating film surface.

[0006] Patent Document 3 discloses the incorporation of a hydrocarbon compound having a reactive thiol group into a rubber composition in order to impart viscosity and improve the crosslinking yield. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2015-81305 [Patent Document 2] Japanese Patent Application Publication No. 09-059566 [Patent Document 3] Japanese Patent Publication No. 2000-26820 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The present invention aims to provide a polyurethane resin composition that can form a cured film with high adhesion and elongation to various materials and has excellent storage stability. [Means for solving the problem]

[0009] The inventors of the present invention have found that the above problems can be solved by combining aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and aliphatic diols as raw material components for polyester polyols, and further incorporating hydrocarbon compounds having reactive thiol groups, thereby completing the present invention.

[0010] In other words, the present invention relates to a polyurethane resin composition containing (A) a polyester polyol which is a condensation product of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol, (B) a polyisocyanate, and (C) a hydrocarbon compound having a reactive thiol group.

[0011] It is preferable that the polyester polyol (A) is a polyester diol.

[0012] It is preferable that the (B) polyisocyanate is an adduct of an aliphatic diisocyanate having 6 or more carbon atoms and an aliphatic polyol.

[0013] It is preferable that the number of reactive thiol groups in the (C) hydrocarbon compound is 1.

[0014] Furthermore, it is preferable that (D) the compound contains a silicone compound having a reactive hydroxyl group.

[0015] Furthermore, the present invention relates to a one-component paint comprising the polyurethane resin composition described above. [Effects of the Invention]

[0016] The polyurethane resin composition of the present invention can form a cured film with high adhesion and elongation (elasticity and flexibility) to various materials, and also exhibits excellent storage stability. [Modes for carrying out the invention]

[0017] The polyurethane resin composition of the present invention contains (A) a polyester polyol which is a condensation product of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol, (B) a polyisocyanate, and (C) a hydrocarbon compound having a reactive thiol group.

[0018] <(A) Polyester polyol> The (A) polyester polyol used in this invention is a condensation product of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol.

[0019] 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), naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, and reactive derivatives thereof such as acid anhydrides, alkyl esters and acid halides. Among these, from the viewpoints of availability as a raw material and cost, aromatic dicarboxylic acids having 8 to 14 carbon atoms and reactive derivatives thereof are preferred, and o-phthalic acid, m-phthalic acid, p-phthalic acid and reactive derivatives thereof are particularly preferred. These dicarboxylic acids can be used alone or in combination of two or more kinds thereof.

[0020] The aliphatic dicarboxylic acid is not particularly limited, and examples thereof include linear, branched or cyclic aliphatic dicarboxylic acids, and reactive derivatives thereof such as acid anhydrides, alkyl esters and acid halides. Specific examples thereof 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 availability as a raw material and cost, aliphatic dicarboxylic acids having 4 to 9 carbon atoms and reactive derivatives thereof are preferred; among these, linear aliphatic dicarboxylic acids and reactive derivatives thereof are more preferred, and adipic acid and reactive derivatives thereof are particularly preferred. These dicarboxylic acids can be used alone or in combination of two or more kinds thereof.

[0021] Regarding the ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid, the aromatic dicarboxylic acid is preferably contained in an amount of 20 to 80% by weight based on 100 parts by weight of the total of the two, and more preferably 30 to 70% by weight. When the content is less than 20% by weight, the adhesion to a substrate tends to decrease; when the content exceeds 80% by weight, the elasticity and flexibility of a coating film tend to decrease when the polyurethane resin composition is used as a coating material.

[0022] The aliphatic diol is not particularly limited, and examples include linear aliphatic diols (such as ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, etc.), branched aliphatic diols (such as 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.) or cyclic aliphatic diols (1,4-bis(hydroxymethyl)cyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane). These diols can be used alone or in combination of two or more. Among these, from the viewpoints 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.

[0023] In addition to the aliphatic diol, an aromatic diol may be used in combination, but among all diol components, the proportion of the aliphatic diol is preferably 60 to 100% by weight, more preferably 70 to 100% by weight, and still more preferably 80 to 100% by weight. If the proportion is less than 60% by weight, when the polyurethane resin composition is used as a coating material, the elasticity and flexibility of the coating film tend to decrease.

[0024] The number of hydroxyl groups contained in (A) polyester polyol is preferably 2 to 4, and more preferably the (A) polyester polyol is a polyester diol.

[0025] The number average molecular weight (Mn) of (A) polyester polyol is preferably 1000 to 30000, and more preferably 10000 to 20000. If the number average molecular weight is less than 1000, the elasticity of the cured product tends to decrease; if it exceeds 30000, the viscosity becomes high and the handling properties tend to decrease significantly. The number average molecular weight can be determined by gel permeation chromatography (GPC) in terms of polystyrene.

[0026] (A) The weight-average molecular weight (Mw) of the polyester polyol is preferably between 2,000 and 60,000, and more preferably between 20,000 and 40,000. If it is less than 2,000, the elasticity tends to decrease, and if it exceeds 60,000, the viscosity becomes high, and the handling properties tend to decrease significantly. The weight-average molecular weight can be determined using GPC in terms of polystyrene equivalent.

[0027] (A) The hydroxyl value of the polyester polyol is preferably 5 to 100 mg KOH / g, and more preferably 5 to 50 mg KOH / g. If it is less than 5 mg KOH / g, there is a tendency for the film strength to decrease due to a decrease in crosslinking density, and if it exceeds 100 mg KOH / g, there is a tendency for the water resistance of the film 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 (according to JIS K 1557-1).

[0028] (A) Polyester polyols can be obtained by dehydrating and condensing aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and aliphatic diols using known methods.

[0029] The ratio of the dicarboxylic acid component (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 in the diol component to the total number of moles of carboxyl groups in the dicarboxylic acid (hydroxyl groups / carboxyl groups) is 0.5 to 1.5, and more preferably 0.8 to 1.2.

[0030] <(B) Polyisocyanate> The (B) polyisocyanate used in the present invention is not particularly limited and includes 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 reactions 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.

[0031] In particular, those having an aliphatic skeleton (aliphatic polyisocyanates or adducts of aliphatic polyisocyanates and aliphatic polyols) are preferred because they yield a highly elastic and highly flexible cured film. Furthermore, from the viewpoint of ease of obtaining 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.

[0032] Polyisocyanates with aliphatic skeletons and those with aromatic skeletons may be used in combination, but the proportion of those with aliphatic skeletons is preferably 50 to 100% by weight of the total polyisocyanate components, more preferably 70 to 100% by weight, and even more preferably 80 to 100% by weight. If the proportion is less than 50% by weight, the elasticity and flexibility of the cured film tend to decrease.

[0033] The NCO% (weight percentage) of NCO groups in the polyisocyanate is preferably 2-30%, and more preferably 2-20%.

[0034] <(C) Hydrocarbon compounds having reactive thiol groups> (C) Hydrocarbon compounds having reactive thiol groups impart storage stability to polyurethane resin compositions. "Reactive thiol group" means a thiol group that is reactive with (B) polyisocyanate groups. When (A) polyester polyol and (B) polyisocyanate are mixed, urethane bonds are formed at room temperature, resulting in poor storage stability. (C) Hydrocarbon compounds having reactive thiol groups form adducts with (B) polyisocyanate and suppress the reaction between (A) polyester polyol and (B) polyisocyanate.

[0035] The reaction between (C) a hydrocarbon compound having a reactive thiol group and (B) polyisocyanate is an equilibrium reaction. In a system containing components (A), (B), and (C), the formation of an adduct between component (B) and component (C) occurs preferentially, and the formation of a urethane bond between (A) polyester polyol and (B) polyisocyanate is suppressed. When the hydrocarbon compound having a reactive thiol group (C) is lost from the system by volatilization or other means, a urethane bond is formed between (A) polyester polyol and (B) polyisocyanate.

[0036] (C) The hydrocarbon structure of the hydrocarbon compound having a reactive thiol group is not particularly limited and includes linear, branched, or cyclic aliphatic hydrocarbons and aromatic hydrocarbons. (C) The number of carbon atoms in the hydrocarbon compound having a reactive thiol group is preferably 2 to 20, more preferably 3 to 18, even more preferably 8 to 16, and particularly preferably 10 to 14. If the number of carbon atoms is less than 2, it tends to produce an odor when used. If the number of carbon atoms exceeds 20, the volatility is low and the performance of the cured film tends to decrease when used as a paint.

[0037] (C) The hydrocarbon compound having a reactive thiol group preferably has one functional thiol group. If it has two or more functional thiols, it tends to crosslink with component (B), reducing the storage stability of the polyurethane resin composition.

[0038] (C) Specific examples of hydrocarbon compounds having a reactive thiol group include propyl mercaptan, dodecyl mercaptan, hexadecyl mercaptan, and octadecyl mercaptan. Among these, those that are volatile under normal temperature and atmospheric pressure conditions are preferred, with propyl mercaptan, dodecyl mercaptan, and hexadecyl mercaptan being preferred.

[0039] <(D) Silicone compounds having reactive hydroxyl groups> The polyurethane resin composition of the present invention preferably further contains (D) a silicone compound having a reactive hydroxyl group. "Reactive hydroxyl group" means a hydroxyl group that is reactive with an isocyanate group. Because the silicone compound acting as a slip agent has a reactive hydroxyl group, it reacts with the polyisocyanate and is fixed to the cured film, allowing the slip properties to be maintained for a long period of time.

[0040] (D) In ​​silicone compounds 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. (D) In ​​addition to the reactive hydroxyl group, the silicone compound having a reactive hydroxyl group may also have other reactive groups such as (meth)acrylic groups, vinyl groups, amino groups, epoxy groups, and non-reactive groups such as alkyl groups, ester groups, aralkyl groups, phenyl groups, and polyether groups.

[0041] (D) The number average molecular weight of the silicone compound having reactive hydroxyl groups is preferably 1,000 to 20,000, and more preferably 3,000 to 15,000. If it is less than 1,000, it tends to detach from the film and the effect does not last, and if it exceeds 20,000, it becomes difficult to orient on the film surface and tends not to produce an anti-tack effect.

[0042] (D) The weight-average molecular weight of the silicone compound having reactive hydroxyl groups is preferably 2,000 to 40,000, and more preferably 6,000 to 30,000. If it is less than 2,000, it tends to detach from the film and the effect does not last, and if it exceeds 40,000, it becomes difficult to orient on the film surface and tends not to produce an anti-tack effect.

[0043] (D) The hydroxyl value of the silicone compound having reactive hydroxyl groups is preferably 30 to 200 mg KOH / g, and more preferably 80 to 150 mg KOH / g. If it is less than 30 mg KOH / g, it tends to detach from the membrane and the effect does not last, and if it exceeds 200 mg KOH / g, the water solubility increases and it tends to detach from the membrane due to moisture.

[0044] <Other additives> The polyurethane resin composition of the present invention may optionally contain various additives such as pigments, dispersants, solvents, leveling agents, curing catalysts, thickeners, ultraviolet absorbers, light stabilizers, antioxidants, and silane coupling agents.

[0045] The pigments are not particularly limited, and examples of coloring pigments include titanium dioxide, iron oxide-based yellow and red pigments, carbon black, phthalocyanine blue, phthalocyanine green, benzoimidazolone, quinaclindone, anthraquinone, naphthol, and various azo pigments, which can be used alone or in combination of two or more depending on the desired color. Examples of extender pigments include calcium carbonate, talc, clay, alumina white, barium sulfate, basic magnesium carbonate, barite powder, diatomaceous earth, and silica. Examples of rust-preventive pigments include lead cyanamide, lead oxide, zinc chromate, strontium chromate, and zinc oxide. The amount added is not particularly limited, but for example, 1 to 300 parts by weight can be added per 100 parts by weight of (A) polyester polyol.

[0046] The dispersant is not particularly limited, and examples include polycarboxylic acid-based pigment dispersants and polyamine-based pigment dispersants. The amount added is also not particularly limited, but for example, 0.1 to 10 parts by weight can be added per 100 parts by weight of (A) polyester polyol.

[0047] The solvent is not particularly limited and examples 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 solvent content in the resin composition is also not particularly limited and can be adjusted as needed.

[0048] The leveling agent is not particularly limited and examples include polyether-based leveling agents, fluorine-based leveling agents, polyester-based leveling agents, siloxane-based leveling agents, silicone-based leveling agents, and acrylic-based leveling agents. The amount of leveling agent is not particularly limited, but 0.1 to 10 parts by weight and more preferably 0.2 to 5 parts by weight per 100 parts by weight of (A) polyester polyol is preferred.

[0049] The silane coupling agent is not particularly limited and includes 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 silane coupling agent is not particularly limited, but is preferably 0.1 to 10 parts by weight, and more preferably 0.2 to 5 parts by weight, per 100 parts by weight of (A) polyester polyol.

[0050] <Ratio of essential ingredients> The ratio of the total number of moles of isocyanate groups in (B) polyisocyanate to the total number of moles of hydroxyl groups in (A) polyester polyol (and if (D) silicone compound having reactive hydroxyl groups is included, the total number of moles of hydroxyl groups in that component as well) (isocyanate groups / hydroxyl groups) is preferably 0.7 to 1.5, and more preferably 0.8 to 1.2.

[0051] (B) The amount of polyisocyanate added is preferably 0.1 to 50 parts by weight, and more preferably 1 to 10 parts by weight, per 100 parts by weight of (A) polyester polyol.

[0052] (C) The amount of hydrocarbon compound having a reactive thiol group is preferably 0.1 to 8 parts by weight, and more preferably 0.5 to 5 parts by weight, per 100 parts by weight of polyester polyol (A).

[0053] Furthermore, the molar ratio (isocyanate group / thiol group) of the thiol groups in the hydrocarbon compound having a reactive thiol group (C) to the isocyanate groups in (B) polyisocyanate is preferably 0.1 to 3, and more preferably 0.5 to 2.

[0054] (D) The amount of the silicone compound having a reactive hydroxyl group is preferably 0.3 to 10 parts by weight, and 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 tack of the cured film may not be sufficiently suppressed, and if it exceeds 10 parts by weight, the water resistance will decrease, and the surface of the cured film may whiten in a humid environment.

[0055] The method for producing the polyurethane resin composition is not particularly limited, and components (A), (B), and (C) may be mixed together or in any order. To improve storage stability, it is preferable to react components (B) and (C) beforehand to form adduct bodies and then mix these adduct bodies with component (A).

[0056] <Method for forming a hardened film> A cured film can be formed by applying the polyurethane resin composition of the present invention onto a substrate and curing it. The application method is not particularly limited and includes spraying, brushing, rolling, bar coating, spin coating, dipping, printing, inkjet printing, etc. The curing method is also not particularly limited and includes known methods such as curing by drying at room temperature and accelerated curing by heating.

[0057] When applying by spray, the polyurethane resin composition of the present invention is filled into an aerosol container together with a filler. The filler is not particularly limited as long as it is suitable for use in aerosols, and examples include dimethyl ether, liquefied petroleum gas (LPG), and fluorinated hydrocarbons. Among these, dimethyl ether is preferred. The amount of filler used is preferably such that the volume ratio of the polyurethane resin composition to the filler is 55:45 to 40:60, and more preferably 50:50 to 45:55.

[0058] The material of the base material is not particularly limited and includes natural rubber, synthetic rubber (styrene-butadiene rubber, nitrile rubber, butyl rubber, urethane rubber, chloroprene rubber, ethylene-propylene rubber, silicone rubber, etc.), metals (iron, stainless steel (SUS304, SUS430, etc.), aluminum (aluminum 5052, aluminum 6063, etc.), copper, brass, etc.), resins (polyethylene, polypropylene, electrostatically treated polypropylene, polycarbonate resin, nylon 6, nylon 66, PET resin, acrylic resin, polyurethane resin, polyester resin, polyacetal resin, ABS resin, rigid polyvinyl chloride, flexible polyvinyl chloride, vinyl acetate resin, etc.), glass, ceramics, tiles, concrete, woven fabrics, nonwoven fabrics, synthetic leather, natural leather (cowhide, etc.), etc. The fibers constituting the woven fabrics and nonwoven fabrics may be the aforementioned resins, or they may be cotton, silk, etc. These may be used individually or as composite materials combining two or more types.

[0059] The form of the substrate is not particularly limited and includes films, sheets, molded articles, foamed types, and foam types.

[0060] The thickness of the cured film is not particularly limited, but 5 to 200 μm is preferred. If the thickness is less than 5 μm, the film strength is insufficient and it tends to break, and if it exceeds 200 μm, the reactivity becomes uneven and the tactile feel tends to deteriorate. If a thickness exceeding 200 μm is required, the coating and curing process can be repeated in several stages.

[0061] The cured film preferably exhibits an elongation of 300% or more when the film thickness is 50 μm, and more preferably 350% or more. Here, elongation is the value obtained by a tensile test of the free film.

[0062] <Application> The polyurethane resin composition of the present invention can be suitably used as a coating for clothing such as underwear, sportswear, stockings, socks, and supporters, and as a coating 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 for forming a transparent coating film.

[0063] Furthermore, the polyurethane resin composition of the present invention can be suitably used as a chipping-resistant primer to prevent scratches and corrosion caused by flying stones and the like on the underbody panels and bumper portions of automobiles. In this case, the chipping-resistant primer layer can be formed on a substrate such as the underbody panels and bumper portions of an automobile, or under the intermediate coating layer. On top of the chipping-resistant primer layer, a metallic base layer, an intermediate coating layer, a clear coat layer, etc., may be further laminated in any order.

[0064] Furthermore, the polyurethane resin composition of the present invention can 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 in the manufacture of laminated glass for automobiles, aircraft, ships, and buildings.

[0065] The polyurethane resin composition of the present invention may be used in either a one-component or two-component form, but due to its excellent storage stability, it can be used as a one-component paint, adhesive, or primer, and is particularly suitable for use as a one-component spray paint. [Examples]

[0066] 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. Unless otherwise specified, "parts" means parts by weight.

[0067] (1) Manufacturing of paint compositions Example 1 A mixture of dicarboxylic acids was obtained by mixing 14 parts terephthalic acid and 14 parts isophthalic acid, which are aromatic dicarboxylic acids, with 30 parts adipic acid, which is an aliphatic dicarboxylic acid. Eight parts ethylene glycol, seventeen parts neopentyl glycol, and seventeen parts 1,6-hexanediol, which are aliphatic diols, were mixed with this mixture and condensed by a known method to obtain polyester polyol (A1). The Mn of (A1) was 17400, the Mw was 34100, and the hydroxyl value (solid) was 10 mgKOH / g. To 100 parts of the obtained (A1), one part of a silicone compound (KR-500 (a silicone compound having a methoxysilyl group, containing 28% by weight of methoxy groups), manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed, and then 96 parts of cyclohexanone were added as a solvent to form the main component.

[0068] Four parts of hexamethylene diisocyanate and trimethylolpropane adduct (Duranate E402-90T (NCO%: 8.5%) manufactured by Asahi Kasei Corporation) and four parts of n-dodecyl mercaptan were mixed. This mixture was added to the main component to obtain a paint composition.

[0069] Example 2 A paint composition was obtained in the same manner as in Example 1, except that 4 parts of propyl mercaptan were used instead of n-dodecyl mercaptan.

[0070] Example 3 A coating composition was obtained in the same manner as in Example 1, except that 4 parts of n-hexadecyl mercaptan were used instead of n-dodecyl mercaptan.

[0071] Comparative Example 1 A coating composition was obtained in the same manner as in Example 1, except that n-dodecyl mercaptan was not used and 100 parts of cyclohexanone were used instead.

[0072] (2) Evaluation of paint composition (2-1) Storage stability of paint composition The paints were left to stand in an environment of 50°C and humidity of 95% or higher for the period indicated in Table 1. A rating of ○ was given if the viscosity increase after standing was less than ±5 KU, and × if it was ±5 KU or more.

[0073] (2-2) Storage stability of aerosols The paint compositions of each example and comparative example, along with dimethyl ether, were filled into spray cans in a volume ratio of 9:11. (i) Shaking and stirring Aerosol spray cans were left standing in an environment of 50°C and humidity of 95% or higher for the period indicated in Table 1. After standing, the aerosol spray cans were shaken up and down, and the number of shakes until the stirring ball made a sound was counted. A score of ○ was given for less than 10 shakes, and a score of × was given for 10 or more shakes.

[0074] (ii) Full injection Aerosol spray cans were left standing in an environment of 50°C and humidity of 95% or higher for the period indicated in Table 1. After standing, the condition of the nozzle of the aerosol spray can was observed when the entire contents were sprayed. A ○ was given when there was no difference in the spray condition from start to finish and no aggregation occurred during film formation, and a × was given when the spray condition changed and / or aggregation occurred during film formation.

[0075] (2-3) Paint film performance The paint composition was applied to a natural rubber substrate to form a coating film with a thickness of 50 μm. (i) Exterior The film formation (JIS K 5600-3) and color and gloss (JIS K 5600-4) were evaluated according to the respective JIS standards. A circle (○) indicated good appearance, a triangle (△) indicated moderate appearance, and a cross (×) indicated insufficient appearance. (ii) Water resistance The coating film was immersed in 40°C hot water for 72 hours (JIS K 5600-6-2). The color and gloss of the coating film after immersion were evaluated as follows: ○ for good, △ for moderate, and × for insufficient. (iii) Stretchability The elongation rate of the coating film was measured by tensile deformation at both ends. The elongation rate (%) is expressed as the ratio of the length of the substrate at the time the coating film broke under tension to the length before tension. A ○ was given when the difference in elongation rate compared to the case without thiols (Comparative Example 1) was less than 20%, and a △ was given otherwise. (iv) Solvent resistance A rubbing test was performed on the coating film by rubbing it 100 times with a cloth dampened with ethanol. The color and gloss of the coating film after the test were evaluated as follows: ○ if good, △ if moderate, and × if insufficient.

[0076] (2-4) Odor of paint composition The odor of the paint composition during use was checked. A circle (○) was used to indicate no odor, and a triangle (△) indicated an odor. [Table 1]

[0077] The paint composition of Comparative Example 1 did not contain hydrocarbon compounds having reactive thiol groups, and therefore had poor storage stability. The paint compositions of Examples 1 to 3 had excellent storage stability, and their coating films also possessed sufficient performance.

Claims

1. (A) Polyester polyols which are condensation reaction products of aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and aliphatic diols. (B) Polyisocyanates, which are adducts of aliphatic diisocyanates with 6 or more carbon atoms and aliphatic polyols. (C) A hydrocarbon compound having a reactive thiol group, wherein the number of reactive thiol groups is 1, and (D) Silicone compounds having reactive hydroxyl groups A polyurethane resin composition containing a one-component paint, a one-component adhesive, or a one-component primer.

2. The polyurethane resin composition according to claim 1, wherein the (A) polyester polyol is a polyester diol.

3. A one-component paint comprising the polyurethane resin composition according to any one of claims 1 to 2.

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