Polyurea resin composition

Abstract

To provide a polyurea resin composition which has a good viscosity under a solventless condition, is excellent in wall surface coatability, shortens a curing time, and can form a coating film excellent in chemical resistance and scratch resistance.SOLUTION: A polyurea resin composition containing a polyisocyanate compound (A), an aspartic acid ester compound (B), and a polyol compound (C), wherein the polyisocyanate compound (A) contains 51% by mass or more of an aliphatic polyisocyanate compound or a derivative thereof, the aspartic acid ester compound (B) is a compound represented by the following general formula (1), and the polyol compound (C) is an aliphatic alcohol: X (-NH-CH (CH2COOR2) COOR1) n (1) wherein X is an n-valent organic group, n is an integer of at least 2, and R1 and R2 are the same or different organic groups. ) SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyurea resin composition. [Background technology]

[0002] Polyurea resins, which are composed of polyisocyanate compounds and polyamine compounds, have excellent physical properties and can be used without solvents, and are therefore used as reinforcing materials for aging buildings and frameworks, and as materials that impart durability to natural disasters such as earthquakes.

[0003] When a polyurea resin composition containing a polyisocyanate compound and a polyamine compound contains an aspartic acid ester compound as the polyamine compound, it can be applied using a trowel or roller, i.e., hand application. Furthermore, since the aspartic acid ester compound has a lower viscosity than the polyol compound, which is one of the main components of polyurethane resins, a polyurea resin composition containing an aspartic acid ester compound can be formulated as a high-solids or solventless formulation while still having a viscosity suitable for hand application. Furthermore, since the amino group of the aspartic acid ester compound reacts more quickly with the isocyanate group than the hydroxy group of the polyol compound, a polyurea resin composition containing an aspartic acid ester compound has a faster curing rate even at room temperature than a polyurethane resin composition, and the resulting polyurea resin has excellent mechanical strength.

[0004] On the other hand, due to the chemical structure of the aspartic acid ester compound, the resulting polyurea resin tends to be a hard and brittle cured product. As a technique for solving this problem, for example, Patent Document 1 discloses the use of a polyisocyanate obtained from a polyol compound having a specific structure and an aliphatic diisocyanate monomer as a polyisocyanate compound, thereby improving the scratch resistance, which was an issue due to the hardness of the polyurea resin, and furthermore, obtaining a polyurea resin that is excellent in chemical resistance and weather resistance. Furthermore, Patent Document 2 discloses the use of a polyisocyanate compound containing a specific amount of an isocyanurate trimer, and a resin composition having good viscosity and pot life even under solvent-free conditions is obtained, and a polyurea resin having excellent scratch resistance is obtained. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 163959 [Patent Document 2] Japanese Patent Publication No. 2022-66853 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the polyurea resin composition disclosed in Patent Document 1 requires the addition of a dilution solvent in order to be used as a coating material, and therefore there is room for further improvement in terms of making it a solvent-free formulation. The polyurea resin composition disclosed in Patent Document 2 is solvent-free and has a low viscosity, and the resulting coating film has excellent scratch resistance, but the low viscosity can sometimes result in poor wall coating properties. Furthermore, the coating films obtained from the resin compositions disclosed in both of the above patent documents require curing at 23°C for 7 days when evaluating chemical resistance, and depending on the application, a resin composition that can further shorten the curing time has been desired.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polyurea resin composition that has good viscosity under solvent-free conditions, excellent wall surface coating properties, a shortened curing time, and is capable of forming a coating film that is excellent in chemical resistance and scratch resistance. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by blending a polyol compound having a specific structure with a polyurea resin composition containing a polyisocyanate compound and an aspartic acid ester compound, and have completed the present invention. That is, the gist of the present invention is as follows.

[0009] [1] A polyurea resin composition containing a polyisocyanate compound (A), an aspartic acid ester compound (B), and a polyol compound (C), The polyisocyanate compound (A) contains an aliphatic polyisocyanate compound or a derivative thereof in an amount of 51 mass% or more, The aspartic acid ester compound (B) is a compound represented by the following general formula (1): A polyurea resin composition, wherein the polyol compound (C) is an aliphatic alcohol. X(-NH-CH(CHCOOR 2 )COOR 1 )n (1) (X is an n-valent organic group, n is an integer of 2 or more, R 1 and R 2 are the same or different organic groups.) [2] The polyurea resin composition according to [1], wherein the molar ratio of the amino groups of the aspartic acid ester compound (B) to the hydroxy groups of the polyol compound (C) (amino groups / hydroxy groups) is 99.5 / 0.5 to 45 / 55. [3] The polyurea resin composition according to [1] or [2], wherein the molar ratio of the isocyanate groups of the polyisocyanate compound (A), the amino groups of the aspartic acid ester compound (B), and the hydroxy groups of the polyol compound (C) (isocyanate groups / (amino groups+hydroxy groups)) is 0.5 to 1.7. [4] The polyurea resin composition according to [1] or [2], wherein the polyisocyanate compound (A) has an isocyanate group content of 5 to 50 mass %. [5] The polyurea resin composition according to [1] or [2], wherein the aliphatic polyisocyanate compound is hexamethylene diisocyanate. [6] The polyurea resin composition according to [1] or [2], wherein the polyol compound (C) has a number average molecular weight of 200 to 5,000 and a hydroxyl value of 10 to 800 mgKOH / g. [7] The polyurea resin composition according to [1] or [2], wherein the polyol compound (C) does not contain an ester bond. [8] The polyurea resin composition according to [1] or [2], characterized in that the viscosity at 25°C immediately after preparation under solvent-free conditions is 100 to 50,000 mPa·s. [Effects of the Invention]

[0010] The polyurea resin composition of the present invention can provide a solvent-free polyurea resin composition that has good viscosity, pot life, and curing time, is excellent in coatability onto wall surfaces, and when formed into a coating film, has excellent chemical resistance and scratch resistance. DETAILED DESCRIPTION OF THE INVENTION

[0011] The polyurea resin composition of the present invention contains a polyisocyanate compound (A), an aspartic acid ester compound (B), and a polyol compound (C).

[0012] <Polyisocyanate compound (A)> The polyisocyanate compound (A) constituting the resin composition of the present invention is a compound having two or more isocyanate groups in one molecule, and may be in the form of a monomer, oligomer, or polymer, and may be modified with a chain extender such as a polyol component.

[0013] The polyisocyanate compound (A) in the present invention must contain an aliphatic polyisocyanate compound or a derivative thereof in an amount of 51 mass % or more, more preferably 75 mass % or more, even more preferably 80 mass % or more, and particularly preferably 100 mass %. When the content of the aliphatic polyisocyanate compound or a derivative thereof in the polyisocyanate compound (A) is 51 mass % or more, the reactivity with the aspartic acid ester compound (B) is suppressed, and a good pot life can be achieved.

[0014] Examples of aliphatic polyisocyanate compounds include 1,6-hexamethylene diisocyanate (HDI), 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl caproate, lysine diisocyanate, trioxyethylene diisocyanate, isophorone diisocyanate, 1,4 -bis(isocyanatomethyl)cyclohexane, 4,4'-methylenebis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatoethyl)cyclohexane, 1,4-bis(isocyanatoethyl)cyclohexane, 2,5- or 2,6-bis(isocyanatomethyl)norbornane (NBDI), and hydrogenated aromatic polyisocyanates. Among these, 1,6-hexamethylene diisocyanate (HDI) is preferred as an aliphatic polyisocyanate compound in terms of pot life and curing time.

[0015] Examples of the derivatives of aliphatic polyisocyanate compounds include isocyanate-terminated prepolymers obtained by reacting an aliphatic polyisocyanate compound with a polyamine or a polyol, allophanate-modified products, urea-modified products, carbodiimide-modified products, biuret-modified products, uretdione-modified products, and isocyanurate-modified products, as well as those modified into water-dispersible types. When the polyisocyanate compound (A) contains a derivative of an aliphatic polyisocyanate compound such as an isocyanate-terminated prepolymer or modified product, the resulting coating film has improved properties such as chemical resistance. The above-mentioned derivatives of the aliphatic polyisocyanate compounds can be obtained by known methods.

[0016] In addition to the aliphatic polyisocyanate compound, the polyisocyanate compound (A) may contain other isocyanate components according to the desired performance such as physical properties, usable life, etc. Examples of such isocyanate components include aromatic polyisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and 1,5-naphthylene diisocyanate. Among these, when HDI is used as the aliphatic polyisocyanate compound, from the viewpoint of compatibility with HDI, the isocyanate component other than HDI is preferably 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate (MDI), xylylene diisocyanate, 1,5-naphthylene diisocyanate, 1,5-pentamethylene diisocyanate, or 4,4'-methylenebis(cyclohexyl isocyanate), more preferably 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate, or 1,5-pentamethylene diisocyanate. Two or more of these may also be used in combination. In addition, isocyanate-terminated prepolymers, allophanate-modified products, urea-modified products, carbodiimide-modified products, biuret-modified products, uretdione-modified products, isocyanurate-modified products, and those modified to be water-dispersible can also be used in the same way.

[0017] The isocyanate group content in the polyisocyanate compound (A) is preferably 5 to 50 mass%, more preferably 5 to 35 mass%, even more preferably 10 to 33 mass%, and particularly preferably 15 to 30 mass%. A polyurea resin composition containing a polyisocyanate compound (A) with an isocyanate group content higher than the above range may fail to provide a coating film with sufficient physical properties, and if the isocyanate group content in the polyisocyanate compound (A) is lower than the above range, the resin composition may not have a good pot life.

[0018] The viscosity of the polyisocyanate compound (A) at 25°C is preferably 1,000 to 30,000 mPa·s, more preferably 1,500 to 25,000 mPa·s, and even more preferably 2,000 to 20,000 mPa·s. A coating material made from a resin composition containing a polyisocyanate compound (A) with a viscosity at 25°C of more than 30,000 mPa·s may take a long time to mix uniformly with other materials or may be difficult to apply uniformly. On the other hand, if the viscosity of the polyisocyanate compound (A) is less than 1,000 mPa·s, the coating material may sag when applied to a wall, and a uniform coating film may not be obtained.

[0019] <Aspartic acid ester compound (B)> The aspartic acid ester compound (B) constituting the resin composition of the present invention is a compound represented by the following general formula (1). X(-NH-CH(CHCOOR 2 )COOR 1 )n (1) (X is an n-valent organic group, n is an integer of 2 or more, R 1 and R 2 are the same or different organic groups.)

[0020] Commercially available aspartic acid ester compounds (B) include, for example, "Amicure IC-221," "Amicure IC-321," and "Amicure IC-322" manufactured by Evonik, and "Feispartic F220," "Feispartic F420," and "Feispartic F520" manufactured by Feiyang.

[0021] <Other amine compounds> The polyurea resin composition of the present invention may contain an amine compound other than the aspartic acid ester compound (B) for the purpose of adjusting the coating film properties and usable life. Other amine compounds include aromatic amine compounds such as 4,4'-diamino-3,3'-dichlorodiphenylmethane and diethyltoluenediamine, polyether amine compounds such as O,O'-bis(2-aminopropyl)propylene glycol and polyalkylene oxide-di-p-aminobenzoate, and aliphatic amine compounds such as hexamethylenediamine, nonanediamine, and reaction products of epoxy compounds and primary amines. Either primary or secondary amines can be used as the other amine compounds.

[0022] The content of the other amine compound is preferably 0 to 20 parts by mass relative to 100 parts by mass of the total of the other amine compound and the aspartic acid ester compound (B). If the content of the other amine compound exceeds 20 parts by mass, the polyurea resin composition may not have a sufficient usable life.

[0023] <Polyol compound (C)> The polyurea resin composition of the present invention contains an aliphatic alcohol as the polyol compound (C), which allows the polyurea resin composition to achieve good pot life, viscosity, and wall surface coatability. In the present invention, the polyol compound (C) refers to a compound having two or more hydroxy groups in its chemical structure, and the aliphatic alcohol refers to one not containing an aromatic ring in its chemical structure.

[0024] Examples of the polyol compound (C) include, as low molecular weight compounds, dihydric alkyl alcohols such as ethylene glycol, propylene glycol, and 1,6-hexanediol, trihydric alkyl alcohols such as glycerin, and tetrahydric or higher alkyl alcohols such as diglycerin, erythritol, and sorbitol; and examples of high molecular weight compounds include oligomers or polymers (wherein the terminal monomer component is an aliphatic alcohol) such as polyester polyols, polyether polyols, acrylic polyols, polyolefin polyols, polyurethane polyols, and alkylene oxide adducts of amines. Among these, from the viewpoint of the chemical resistance of the resulting coating film, preferred are divalent or higher alkyl alcohols, polyether polyols, polyolefin polyols, polyurethane polyols and other polyols not containing an ester bond, and alkylene oxide adducts of amines, with divalent to tetravalent alkyl alcohols, polyether polyols and polyolefin polyols being more preferred, and polyether polyols and alkylene oxide adducts of amines being even more preferred.

[0025] The number average molecular weight of the polyol compound (C) is not particularly limited, but is preferably 200 to 5,000, more preferably 400 to 4,000, and even more preferably 500 to 3,000. If the number average molecular weight of the polyol compound (C) is less than 200, the resin composition may have a short pot life, whereas if the number average molecular weight exceeds 5,000, it may be difficult to achieve an improved curing rate, or the resulting coating film may have poor scratch resistance.

[0026] The hydroxyl value of the polyol compound (C) is not particularly limited, but is preferably 10 to 800 mgKOH / g, more preferably 30 to 600 mgKOH / g, and even more preferably 50 to 400 mgKOH / g. A polyol compound (C) with a hydroxyl value of less than 10 mgKOH / g may be less effective, while a polyol compound (C) with a hydroxyl value of more than 800 mgKOH / g may result in a coating film with a poor appearance.

[0027] <Polyurea resin composition> In the resin composition of the present invention, the molar ratio of the amino groups of the aspartic acid ester compound (B) to the hydroxy groups of the polyol compound (C) (amino groups / hydroxy groups) is preferably 99.5 / 0.5 to 45 / 55, more preferably 99.5 / 0.5 to 50 / 50, and even more preferably 99 / 1 to 60 / 40. If the proportion of amino groups in the aspartic acid ester compound (B) is higher than 99.5 mol % relative to the total of the amino groups in the aspartic acid ester compound (B) and the hydroxy groups in the polyol compound (C), the resin composition may not easily achieve the effects of containing the polyol compound (C), and if the proportion of amino groups in the aspartic acid ester compound (B) is lower than 50 mol %, the resulting coating film may have poor chemical resistance and scratch resistance.

[0028] In the resin composition of the present invention, the molar ratio of isocyanate groups in the polyisocyanate compound (A), amino groups in the aspartic acid ester compound (B), and hydroxy groups in the polyol compound (C) (isocyanate groups / (amino groups+hydroxy groups)) is preferably 0.5 to 1.7, more preferably 0.6 to 1.5, even more preferably 0.7 to 1.4, and particularly preferably 0.8 to 1.3. If the molar ratio is less than 0.5, the resulting coating film may not be cured, whereas if the molar ratio exceeds 1.7, the resin composition may be prone to side reactions such as foaming, and the resulting coating film may have reduced chemical resistance.

[0029] The viscosity of the polyurea resin composition of the present invention at 25°C immediately after preparation under solvent-free conditions is preferably 100 to 50,000 mPa·s, more preferably 1,000 to 30,000 mPa·s, and particularly preferably 1,500 to 15,000 mPa·s. If the viscosity of the resin composition is less than 100 mPa·s, it may be difficult to obtain a coating film with sufficient thickness, and if it exceeds 50,000 mPa·s, workability during application may be reduced.

[0030] The polyurea resin composition of the present invention may contain a catalyst in order to improve the physical properties of the resulting coating film and to adjust the usable time and curing temperature. Specific examples of catalysts include tertiary amines such as triethylamine, tributylamine, triethylenediamine, 2-dimethylaminoethyl ether, diazabicycloundecene, and N-methylmorpholine; metal catalysts such as dibutyltin diacetate, dibutyltin laurate, 3-diacetoxytetrabutylstannoxane, tin octenoate, tin chloride, butyl tin trichloride, bismuth trichloride, bismuth octenoate, tetrakis(2-ethylhexyl)titanate, tetrabutoxytitanium, and metal salts of acetoacetic acid; and quaternary ammonium salts.

[0031] The polyurea resin composition of the present invention may contain additives as needed. Examples of additives include silica, basic inorganic salts, pH adjusters, metal oxide fine particles, tackifiers, waxes, UV absorbers, leveling agents, wetting agents, antifoaming agents, anti-popping agents, anti-sagging agents, paint spread improvers, thixotropy-imparting agents, pigments, dyes, dispersants, diluents, and fillers. These may be used alone or in combination of two or more. The additives may also be added in advance to the polyisocyanate compound (A) or the aspartic acid ester compound (B). The amount of the additive to be added can be determined appropriately depending on the purpose.

[0032] The polyurea resin composition of the present invention may contain other resins as needed, such as melamine resins, epoxy resins, polyurethane resins, polyester resins, and polyolefin resins.

[0033] In addition, the polyurea resin composition of the present invention can use a common organic solvent as a diluent, as long as it is not reactive with the polyisocyanate compound (A). Examples of organic solvents that can be used as diluents include hydrocarbon compounds such as toluene, xylene, and cyclohexane, carbonyl compounds such as acetone, 2-butanone, and isophorone, and ester compounds such as ethyl acetate and butyl acetate. These may be used alone or in combination of two or more. The content of the organic solvent in the resin composition is preferably 10% by mass or less, more preferably 3% by mass or less, and particularly preferably 1% by mass or less. If the content of the organic solvent in the resin composition exceeds 10% by mass, not only may the physical properties of the resulting coating film be reduced, but also the inherent advantage of the polyurea resin, that it can be produced without a solvent, may be lost.

[0034] <Application> The polyurea resin composition of the present invention can be used to form coating films as a primer, intermediate coat, or top coat on materials such as metals such as iron plates and steel plates, plastics, films, sheets, ceramics, glass, concrete, fibers, and paper by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, immersion, roller coating, brush coating, gravure printing, or the like, or can be used as a sizing agent, reinforcing material, or the like. The polyurea resin composition of the present invention can be suitably used to impart aesthetic appearance, weather resistance, water resistance, chemical resistance, rust prevention, abrasion resistance, adhesion, and the like to the above-mentioned materials. The polyurea resin composition of the present invention is also useful as an adhesive, a pressure sensitive adhesive, an elastomer, a foam, a surface treatment agent, and the like.

[0035] As described above, the polyurea resin composition of the present invention can be used as a coating material to form a coating film, and can also be poured into a metal frame to produce a molded article.

[0036] The polyurea resin composition of the present invention is reactive at room temperature and therefore does not usually require heating, but may be heated to accelerate curing after coating, etc., or to improve low-temperature working environments in winter, etc. The curing temperature can be appropriately determined based on the application method and curing time, and is preferably 30 to 80°C from the viewpoint of safety. As a device for heating the resin composition of the present invention, a known device can be used, taking into consideration the viscosity of the resulting polyurethane resin, the shape of the adherend, etc. Specific examples of the heating device include a heating roller, a roller heater, a polyimide heater, an infrared radiation heater, a high-temperature air heater, a heat gun, a dryer, a drying oven, a baking oven, a constant-temperature dryer, a constant-temperature oven, etc. [Example]

[0037] The present invention will be explained in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples in any way. In the examples and comparative examples, the following raw materials were used as they were without purification or distillation.

[0038] <Polyisocyanate compound (A)> A1: 1,6-hexamethylene diisocyanate (Tokyo Chemical Industry Co., Ltd., isocyanate group content 49.9% by mass, viscosity 3 mPa s) A2: Biuret-modified hexamethylene diisocyanate (Asahi Chemical Industry Co., Ltd. "Duranate 24A-100", isocyanate group content 23.5% by mass, viscosity 1,800 mPa s) A3: Nurate-modified hexamethylene diisocyanate (Tosoh Corporation's "Coronate HXR," isocyanate group content 21.9% by mass, viscosity 1,700 mPa·s) A4: Water-dispersible hexamethylene diisocyanate (Asahi Chemical Industry Co., Ltd. "Duranate WL72-100", isocyanate group content 21.3% by mass, viscosity 1,000 mPa s) A5: Isophorone diisocyanate (mixture of isomers) (Tokyo Chemical Industry Co., Ltd., isocyanate group content 37.8% by mass, viscosity 10 mPa s) A6: Polymeric MDI (Tosoh Corporation's "Millionate MR-200," isocyanate group content 30.9% by mass, viscosity 150 mPa·s)

[0039] A7: Isocyanate-terminated HDI prepolymer (isocyanate group content 20.5% by mass, viscosity 2,000 mPa s) synthesized by the following method. A nitrogen atmosphere was created inside a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen inlet tube, and a dropping funnel, and 100 parts by mass of hexamethylene diisocyanate (HDI) and 21.5 parts by mass of polypropylene glycol (number average molecular weight 750) were charged. The temperature inside the reactor was maintained at 95°C for 90 minutes with stirring to carry out a urethanization reaction. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator to obtain an isocyanate-terminated HDI prepolymer with an isocyanate group content of 20.5% by mass, a viscosity of 3,000 mPa s at 25°C, and a number-average molecular weight of 1,520.

[0040] A8: Isocyanate-terminated HDI prepolymer (isocyanate group content 34.8% by mass, viscosity 850 mPa s) synthesized by the following method. An isocyanate-terminated HDI prepolymer was obtained in the same manner as in A7, except that the amount of polypropylene glycol added was changed to 10.8 parts by mass.

[0041] A9: HDI-MDI mixture containing 51% by mass of A2 and 49% by mass of A6 A10: HDI-MDI mixture of 80% by mass of A2 and 20% by mass of A6 A11: MDI-HDI mixture of 40% by mass of A2 and 60% by mass of A6

[0042] A12: Isocyanate-terminated HDI prepolymer (isocyanate group content 21.9% by mass, viscosity 4,200 mPa s) synthesized by the following method. A nitrogen atmosphere was created inside a four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel, and 100 parts by mass of HDI and 16.1 parts by mass of ethylenediamine-propylene oxide adduct (ADEKA Corporation, "EDP-1100", number average molecular weight 1100) were charged. The temperature inside the reactor was maintained at 95°C for 90 minutes with stirring to carry out a urethanization reaction. The cooled reaction mixture was filtered, and unreacted HDI was removed using a thin-film evaporator to obtain an isocyanate-terminated HDI prepolymer with an isocyanate group content of 21.9% by mass, a viscosity of 4,200 mPa.s at 25°C, and a number-average molecular weight of 1,820.

[0043] A13: Isocyanate-terminated HDI prepolymer (isocyanate group content 9.0% by mass, viscosity 4,980 mPa s) synthesized by the following method. A nitrogen atmosphere was created inside a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen inlet tube, and a dropping funnel, and 100 parts by mass of HDI and 33.7 parts by mass of polycaprolactone triol (number average molecular weight 850) were charged. The temperature inside the reactor was maintained at 95°C for 90 minutes with stirring to carry out a urethanization reaction. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator to obtain an isocyanate-terminated HDI prepolymer with an isocyanate group content of 9.0% by mass, a viscosity at 25°C of 4980 mPa s, and a number-average molecular weight of 1520.

[0044] A14: Isocyanate-terminated HDI prepolymer (isocyanate group 23.2% by mass, viscosity 470 mPa s) synthesized by the following method. A four-neck flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was conditioned with nitrogen, and 100 parts by mass of HDI and 0.12 parts by mass of isobutanol were added. The temperature inside the reactor was maintained at 80°C for 2 hours while stirring. 0.08 parts by mass of a solution prepared by diluting the isocyanuration reaction catalyst trimethyl-2-methyl-2-hydroxyethylammonium hydroxide with isobutanol to 5% by mass was added to the flask, and the isocyanuration reaction was carried out. When the conversion rate reached 20% by mass, phosphoric acid was added to terminate the reaction. The reaction solution was then maintained at 160°C for 1 hour. The cooled reaction mixture was filtered and unreacted HDI was removed using a thin-film evaporator, yielding an isocyanate-terminated HDI prepolymer with an isocyanate group content of 23.2% by mass and a viscosity of 470 mPa·s at 25°C.

[0045] <Aspartic acid ester compound (B), amine compound> B1: Aspartic acid ester compound (Feiyang Co., Ltd. "Feispartic F520", amine value 190 mg KOH / g, viscosity 1,400 mPa s) B2: Aspartic acid ester compound (Feiyang "Feispartic F420", amine value 203 mg KOH / g, viscosity 1,450 mPa s) B3: Aspartic acid ester compound (Feiyang Co., Ltd. "Feispartic F220", amine value 241 mg KOH / g, viscosity 80 mPa s) B4: Polytetramethylene oxide-di-p-aminobenzoate (Kumiai Chemical Industry Co., Ltd. "Elasmer 250P", amine value 221 mg KOH / g, viscosity 154 mPa·s (85°C))

[0046] <Polyol compound (C)> C1: Ethylenediamine-propylene oxide adduct (ADEKA "EDP-1100", hydroxyl value 217 mg KOH / g, viscosity 750 mPa s) C2: Glycerin-propylene oxide adduct (ADEKA "G-700", hydroxyl value 224 mg KOH / g, viscosity 230 mPa·s) C3: Polyethylene glycol 200 (PEG-200 manufactured by Tokyo Chemical Industry Co., Ltd., hydroxyl value 565 mg KOH / g, viscosity 60 mPa s) C4: Glycerin-propylene oxide adduct (ADEKA "G-4000", hydroxyl value 43 mg KOH / g, viscosity 230 mPa·s) C5: Polycaprolactone polyol (DIC Corporation "Polylite OD-X-2722", hydroxyl value 58 mg KOH / g, viscosity 8500 mPa s) C6: Bisphenol A propylene oxide adduct (ADEKA "BPX-55", hydroxyl value 141 mg KOH / g, viscosity 1600 mPa s)

[0047] The various physical properties were measured by the following evaluation methods. (1) Isocyanate group content It was determined according to the hydrochloric acid back titration method for di-n-butylamine specified in JIS K 7301.

[0048] (2) Amine value It was determined according to the indicator titration method of JIS K 7237.

[0049] (3) Hydroxyl value It was determined according to the indicator titration method of JIS K 1557-1:2007.

[0050] (4) Molar ratio (amino group / hydroxy group), molar ratio (isocyanate group / (amino group + hydroxy group)) It was calculated from the amount of each component in the resin composition and the isocyanate group content, amine value, and hydroxyl value of each component determined in (1) to (3) above.

[0051] (5) Viscosity The rotational viscosity (mPa·s) at 25°C was measured using a Brookfield Dial Viscometer (Brookfield Engineering Laboratories, Inc., Brookfield Dial Viscometer Model LVT).

[0052] (6) Pot life The resin composition of the present invention was placed entirely in a glass container (100 mL capacity) and quickly mixed at 25°C using a metal stirring rod until it appeared uniform. The same procedure as in the viscosity measurement method described above was then repeated, and the time required for the viscosity to double from the value immediately after mixing was determined, and this was taken as the pot life. The pot life was determined according to the following criteria. 5: Usable time is 40 minutes or more and 120 minutes or less 4: Usable time is between 30 and 40 minutes, or between 120 and 180 minutes 3: Usable time is between 20 and 30 minutes, or between 180 and 300 minutes 2: Usable time is between 10 and 20 minutes, or between 300 and 360 minutes 1: Usable time is less than 10 minutes or more than 360 minutes 0: Curing was too fast to measure pot life, or no increase in viscosity was observed even after 4 hours from mixing the materials For practical purposes, the pot life must be rated "2" or higher, and "3" or higher is more preferable.

[0053] (7) Leveling evaluation Leveling was evaluated based on JIS K 5400. The coating composition was placed in a glass container (100 mL capacity) and quickly mixed at 25°C using a metal stirring rod until it appeared uniform. This was spread onto a 200 x 100 x 2 mm glass plate, and a leveling tester (with a gap of 4 mm) was pressed against the test plate while moving it at a uniform speed. After curing for 24 hours at 25°C, if the unevenness of the coating film created by the leveling tester was equal to or smaller than that of the sample, it was evaluated as "Good", otherwise it was evaluated as "Poor". In addition, if the usable time was too short and the sample had cured before the test, it was evaluated as "-". The sample was the cured product prepared in Example 1.

[0054] (8) Wall coating properties of the coating film (sagging properties) Based on JIS K 5551, the wall coating properties were evaluated based on sagging properties. It was evaluated accordingly. The coating composition was applied to a 200mm x 150mm metal plate using a sag tester (film thickness: 100, 200, 300, 400, 500μm), and the metal plate was immediately placed vertically with the thicker side of the coating facing downwards so that the sag tester's track line was horizontal, and the plate was allowed to cure. The thickness at which no liquid flow (sagging) was observed was evaluated according to the following criteria. 0: The trace line sagged even with a coating thickness of 100 μm 1: The trace line did not sag up to a coating thickness of 100 μm, but sagging occurred at 200 μm. 2: The trace line did not sag up to a coating thickness of 200 μm, but sagging occurred at 300 μm. 3: The trace line did not sag up to a coating thickness of 300 μm, but sagging occurred at 400 μm. 4: The trace line did not sag up to a coating thickness of 400 μm, but sagging occurred at 500 μm. 5: The trace line did not sag even with a coating thickness of 500 μm. In practice, a rating of "2" or higher is necessary, and a rating of "3" or higher is more preferable.

[0055] (9) Chemical resistance The polyurea resin composition was applied to a metal plate using a Baker applicator to a thickness of 1 mm and cured for 24 hours at 25°C. The cured product was then peeled from the metal plate and cut into 20 mm x 20 mm x 1 mm test pieces, which were then immersed in a 10% by mass aqueous sulfuric acid solution, a 5% by mass aqueous acetic acid solution, and a saturated calcium hydroxide solution at 25°C for 60 days. The properties were then evaluated according to the following criteria. 1: One or more of the following was observed on the test piece: swelling, cracking, or leaching 2: No swelling, cracking, or elution was observed in the test piece, and the weight change before and after immersion was 20% or more 3: No swelling, cracking, or elution was observed in the test piece, and the weight change before and after immersion was 15% or more but less than 20% 4: No swelling, cracking, or elution was observed in the test piece, and the weight change before and after immersion was 10% or more but less than 15% 5: No swelling, cracking, or elution was observed in the test piece, and the weight change before and after immersion was less than 10%

[0056] (10) Scratch resistance A commercially available solvent-based two-component acrylic urethane white enamel paint was spray-painted onto an aluminum plate, and after setting, it was baked at 80°C for 2 hours. After curing at room temperature for at least 2 weeks, the surface was polished with #1000 sandpaper until the 60-degree gloss value was 10% or less to prepare a white plate as the substrate. A polyurea resin composition was applied to the substrate using an applicator to a thickness of 80 μm to 100 μm. The coating was then cured at 25°C for 24 hours to obtain a coating. The 20° gloss of the resulting coating was measured in accordance with ISO 11998 using a scrub abrasion tester (manufactured by TQC Corporation). Specifically, the 20° gloss was measured and evaluated using the following method. Specifically, the 20° gloss of the coating surface was measured first. Then, the coating film on the test panel was rubbed back and forth with a brush 200 times. The coating surface was washed with running water, allowed to dry naturally, and then the 20° gloss of the coating surface was measured. The 20° gloss retention was calculated using the following formula, and the scratch resistance was evaluated according to the following criteria. 20° gloss retention = {(20° gloss after test) / (20° gloss before test)} x 100 5: Gloss retention is 35% or more 4: Gloss retention is 30% or more but less than 35% 3: Gloss retention is 25% or more but less than 30% 2: Gloss retention is 20% or more but less than 25% 1: Gloss retention is less than 20%

[0057] Example 1 22.7 g (0.270 mol of isocyanate group) of polyisocyanate compound (A1), 63.6 g (0.216 mol of amino group) of aspartic acid ester compound (B1), and 13.7 g (0.053 mol of hydroxy group) of polyol compound (C1) were mixed at 25°C using a metal stirring rod until a uniform mixture was obtained, thereby obtaining a polyurea resin composition (molar ratio (amino group / hydroxy group) = 80 / 20, molar ratio (isocyanate group / (amino group + hydroxy group)) = 1.0).

[0058] Examples 2 to 27 (Examples 18, 23, 24, 26, and 27 are reference examples), Comparative Examples 1 to 8 A polyurea resin composition was obtained in the same manner as in Example 1, except that the types of (A), (B), and (C) shown in Tables 1 and 2 were used in the molar ratios shown in Tables 1 and 2.

[0059] Tables 1 and 2 show the constitution of the polyurea resin compositions in the examples and comparative examples, and the properties of the obtained polyurea resin compositions.

[0060] [Table 1]

[0061] [Table 2]

[0062] As shown in Tables 1 and 2, the polyurea resin compositions of the examples had good viscosity under solvent-free conditions, excellent wall coating properties, shortened curing times, and were able to form coating films with excellent chemical resistance and scratch resistance. In Comparative Example 1, in which the polyisocyanate compound was an aromatic polyisocyanate compound, the pot life was short and a coating film could not be obtained. The resin compositions of Comparative Example 2, which used a polyisocyanate compound with a low content of aliphatic polyisocyanate compounds, Comparative Example 3, which used an aromatic amine compound instead of an aspartic acid ester compound, and Comparative Examples 4 to 8, which did not contain an aliphatic polyol compound, were poor in wall coating properties.

Claims

1. A polyurea resin composition containing a polyisocyanate compound (A), an aspartic acid ester compound (B), and a polyol compound (C), The polyisocyanate compound (A) contains 51% by mass or more of an aliphatic polyisocyanate compound or its derivative. The aspartic acid ester compound (B) is a compound represented by the following general formula (1), X(-NH-CH(CH) ２ COOR ２ )COOOR １ )n (1) (X is an n-valent organic group, n is an integer greater than or equal to 2, R １ and R ２ These are organic groups of the same or different type. The polyol compound (C) is at least one compound selected from glycerol-propylene oxide adducts and amine alkylene oxide adducts, and the compound has a hydroxyl value of 30 to 800 mgKOH / g. The molar ratio (amino group / hydroxyl group) of the amino group of the aspartic acid ester compound (B) and the hydroxyl group of the polyol compound (C) is 99.5 / 0.5 to 50 / 50. The molar ratio (isocyanate group / (amino group + hydroxyl group)) of the isocyanate group of the polyisocyanate compound (A), the amino group of the aspartic acid ester compound (B), and the hydroxyl group of the polyol compound (C) is 0.5 to 1.

5. A polyurea resin composition characterized by having a 20° gloss retention rate of 25% or more, as determined by the method described below (excluding cases where a thermally conductive inorganic filler is included, and cases where polymer particles with a volume average particle diameter of 0.01 to 0.6 μm are included). <Method for measuring 20° gloss retention rate> The polyurea resin composition is applied to a substrate to a thickness of 80 μm to 100 μm, and cured at 25°C for 24 hours. The 20° gloss of the resulting coating (20° gloss before the test) and the 20° gloss after the coating is subjected to a test in which a brush is rubbed back and forth 200 times, washed with running water, and air-dried (20° gloss after the test) are measured, and the 20° gloss retention rate is calculated from the following formula. 20° gloss retention rate = {(20° gloss after testing) / (20° gloss before testing)} × 100

2. A polyurea resin composition containing a polyisocyanate compound (A), an aspartic acid ester compound (B), and a polyol compound (C), The polyisocyanate compound (A) contains 51% by mass or more of an aliphatic polyisocyanate compound or its derivative. The aspartic acid ester compound (B) is a compound represented by the following general formula (1), X(-NH-CH(CH) ２ COOR ２ )COOOR １ )n (1) (X is an n-valent organic group, n is an integer of 2 or more, and R １ and R ２ are the same or different organic groups.) The polyol compound (C) is polyethylene glycol with a hydroxyl value of 30 to 800 mgKOH / g. The molar ratio (amino group / hydroxyl group) of the amino group of the aspartic acid ester compound (B) and the hydroxyl group of the polyol compound (C) is 99.5 / 0.5 to 50 / 50. The molar ratio (isocyanate group / (amino group + hydroxyl group)) of the isocyanate group of the polyisocyanate compound (A), the amino group of the aspartic acid ester compound (B), and the hydroxyl group of the polyol compound (C) is 0.5 to 1.

5. Under solvent-free conditions, the viscosity at 25°C immediately after preparation is 1500 to 4500 mPa·s. A polyurea resin composition characterized by having a 20° gloss retention rate of 25% or more, as determined by the method described below (excluding cases where a thermally conductive inorganic filler is included, and cases where polymer particles with a volume average particle diameter of 0.01 to 0.6 μm are included). <Method for measuring 20° gloss retention rate> The polyurea resin composition is applied to a substrate to a thickness of 80 μm to 100 μm, and cured at 25°C for 24 hours. The 20° gloss of the resulting coating (20° gloss before the test) and the 20° gloss after the coating is subjected to a test in which a brush is rubbed back and forth 200 times, washed with running water, and air-dried (20° gloss after the test) are measured, and the 20° gloss retention rate is calculated from the following formula. 20° gloss retention rate = {(20° gloss after testing) / (20° gloss before testing)} × 100

3. The polyurea resin composition according to claim 1 or 2, characterized in that the molar ratio (amino group / hydroxyl group) of the amino group of the aspartic acid ester compound (B) and the hydroxyl group of the polyol compound (C) in the polyurea resin composition is 99 / 1 to 60 / 40.

4. The polyurea resin composition according to claim 1 or 2, characterized in that the molar ratio (isocyanate group / (amino group + hydroxyl group)) of the isocyanate group of the polyisocyanate compound (A), the amino group of the aspartic acid ester compound (B), and the hydroxyl group of the polyol compound (C) is 0.6 to 1.

5.

5. The polyurea resin composition according to claim 1 or 2, characterized in that the isocyanate group content of the polyisocyanate compound (A) is 10 to 33% by mass.

6. The polyurea resin composition according to claim 1 or 2, characterized in that the aliphatic polyisocyanate compound is hexamethylene diisocyanate.

7. The polyurea resin composition according to claim 1 or 2, characterized in that the number average molecular weight of the polyol compound (C) is 200 to 5,000 and the hydroxyl value is 30 to 600 mgKOH / g.

8. The polyurea resin composition according to claim 1, characterized in that the viscosity at 25°C immediately after preparation under solvent-free conditions is 100 to 50,000 mPa·s.

9. A polyurea resin composition according to claim 1 or 2, which is a paint for wall coating.