JPH0147501B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a solvent-free coating composition that does not substantially contain organic solvents, and more specifically, it has water resistance,
It has excellent gloss, flexibility, and mildew resistance, and is resistant to pollution and
The present invention relates to a solvent-free coating composition that does not cause safety and health problems and includes a specific acrylic copolymer oligomer and at least one curing agent selected from the group of polyfunctional isocyanates and amino resins. Conventionally, organic solvent-based paints, which have been used exclusively for coating materials such as plastics, metals, wood, and other inorganic building materials, panels, etc., not only emit a characteristic pungent odor and evaporate when applied. Xylol is harmful to the human body, polluting the air and causing photochemical pollution.
Because it contains a large amount of organic solvents such as toluol or various esters and ketones, its use must be strictly controlled due to environmental health issues such as exhaust and ventilation equipment, pollution generation, and occupational safety and health issues. Regulations were put in place. In response to the above-mentioned problems, paint manufacturers have been working to improve and develop paints so that coating operations can be carried out within pollution control limits. As a result, paints such as low-solvent type high solids paints, powder paints, and water-based paints that use water as the dispersion medium have appeared on the market in recent years. There is no problem of generation of photochemical pollutants in the industry, and from that point of view, there is an increasing demand for use in various fields as it is a satisfactory paint. However, powder coatings cannot generally be used due to equipment problems when forming a coating film, and they have the drawback of being limited to being used as an undercoat.In addition, water-based coatings generally have poor water resistance and gloss. Due to problems such as poor quality and difficulty in achieving a beautiful finish, there are problems such as pollution, safety and health, flammability,
There is a strong demand from the industry for a solvent-free paint that does not contain organic solvents or water and is free from problems such as explosion, can be applied over a wide range, and is easy to apply. As a result of intensive research into solving the above-mentioned problems, the present inventors have surprisingly found that a specific acrylic copolymer oligomer, a polyfunctional isocyanate, and an amino resin are selected from the group of coating film-forming substances. The coating composition containing at least one type of curing agent solves all of the above problems at once, and is also a solvent-free coating composition that has excellent flexibility and mildew resistance as well as water resistance and gloss. This discovery led to the completion of the present invention. That is, the present invention provides the following (a) and (b), (a) the following general formulas [] and [], the general formula (In the formula, R ₁ represents H or CH ₃ and R ₂ represents H or an alkyl group.) (In the formula, R ₃ represents H or CH ₃ , and R ₄ represents an alkylene group.) Contains at least 80% by weight of the monomer compound represented by the following as a monomer unit, and has a number average molecular weight of 500 to 8000. , hydroxyl value is 80~
350 and has a glass transition point of 20℃ or less,
A solvent-free coating composition comprising: an acrylic copolymerized oligomer having a viscosity of 100 to 200,000 poise; and (b) at least one curing agent selected from the group of polyfunctional isocyanates and amino resins. is to provide. The solvent-free coating composition of the present invention has the following characteristics. 1) Since it contains virtually no organic solvents, there is no irritating odor, making it particularly suitable for painting anaerobic areas such as food factories and hospitals. Furthermore, there is no danger of ignition or explosion. 2) Absorbs moisture and moisture, does not get soggy or peel, and has excellent water resistance. 3) The paint film is smooth, dust-free, and maintains high gloss. 4) Highly flexible with moderate hardness,
No cracking or peeling occurs during heating and cooling cycles. 5) Since the oxygen permeability of the coating film is extremely low and on the same level as that of vinylidene chloride coatings, the coating film blocks the outside world from the substrate on which the coating film is applied, thereby preventing the growth of mold on the substrate. Many other objects and advantages of the present invention will become more apparent from the following description. What does "solvent-free" mean for solvent-free paint in the present invention?
Ketones such as MIBK, MEK, and acetone; aromatic compounds such as xylol and toluol; organic solvents such as alcohols such as methanol, butanol, and propanol, and solvents such as water. . Moreover, "substantially free" means that the amount of residual monomers in these solvents and oligomers is 5% by weight or less of the coating composition. The acrylic copolymer oligomer constituting the solvent-free coating composition of the present invention is a monomer compound represented by the general formula [], (In the formula, R ₁ represents H or H ₃ , R ₂ represents H or an alkyl group.) and a monomer compound represented by the general formula [ ], (R ₃ represents H or CH ₃ , R ₄ represents an alkylene group) as a monomer unit, at least 80% by weight
Contains a monomer unit number average molecular weight of 500 to 8000,
It has a hydroxyl value of 80 to 350 and a glass transition point (hereinafter sometimes abbreviated as Tg) of 20°C or less,
As long as it has a viscosity of 100 to 200,000 centipoise (hereinafter sometimes abbreviated as CPS), it can be used without particular restrictions. However, from the viewpoint of ease of polymerization and availability, in the monomer compound represented by the general formula [], R ₂ is H or a linear or branched chain having 1 to 8 carbon atoms. Monomeric compounds having an alkyl group are preferred, and these include acrylic acid,
Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate; methacrylic acid, methyl methacrylate,
Examples include ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, and any mixture thereof. Further, as the monomer compound represented by the general formula [], monomer compounds in which R ₄ is represented by an alkylene group having 1 to 6 carbon atoms are preferable, and among these, hydroxymethyl ester of acrylic acid is preferred. , hydroxyethyl ester, hydroxypropyl ester, hydroxybutyl ester,
Examples include hydroxypentyl ester and hydroxyhexyl ester, hydroxymethyl ester, hydroxyethyl ester, hydroxypropyl ester and hydroxyhexyl ester of methacrylic acid, and arbitrary mixtures thereof. The acrylic copolymer oligomer of the present invention contains at least 80% by weight of the general formula [] and the monomer compound represented by the general formula [] as monomer units, but other monomer compounds for copolymerization are Examples include allyl glycidyl ether, glycidyl methacrylate, vinyl acetate, vinyl propionate, ethylene, propylene, butadiene, and the like. The proportion of these monomer compounds to be used is determined appropriately so that the hydroxyl value of the acrylic copolymerized oligomer obtained by copolymerization falls within the range of 80 to 350. The copolymerization can be carried out using any conventionally known copolymerization method in the art, such as bulk copolymerization, suspension copolymerization, emulsion copolymerization, and solution copolymerization under normal pressure or pressure. Copolymerization can be carried out by a conventional radical copolymerization method or ionic copolymerization method. Among these, solution copolymerization and bulk copolymerization are preferred because they tend to yield compounds with relatively small molecular weights. The number average molecular weight of the acrylic copolymer oligomer of the present invention is determined by the GPC method (Gel-permeation method).
chromatography) of 500 to 8,000, preferably 700 to 5,000. If the molecular weight is too low (less than 500), the resulting coating film will be insufficiently hard, sticky and prone to staining, while if it is too high (over 8000), the fluidity of the oligomer will be weakened, making it difficult to use solvent-free paint compositions. It is no longer suitable for use as an object. Further, although the hardness increases, the flexibility becomes insufficient. Furthermore, the hydroxyl value of the acrylic copolymer oligomer of the present invention is preferably in the range of 80 to 350, preferably 80 to 300, particularly preferably 100 to 250. If it is too low (less than 80), it will be too sticky and hardness cannot be expected, and on the other hand, if it is too high (over 350), the viscosity of the oligomer will be high and there will be no fluidity, making it impossible to form a solvent-free coating composition. It is not suitable because it requires a large amount of polyfunctional isocyanate or amino resin and has poor adhesion to the object to be coated and poor weather resistance. In the present invention, the hydroxyl value is a value calculated as follows, based on the measurement method described in Cosmetic Raw Materials Standard Commentary (1st Edition), published by Yakuji Nipposha Co., Ltd. Hydroxyl value measurement method (P-377) The hydroxyl value is the number of milligrams of potassium hydroxide (KOH) required to neutralize acetic acid bound to hydroxyl groups when 1 g of a sample is acetylated under the following conditions. Procedures Unless otherwise specified, accurately weigh approximately 1 g of the sample, place it in a round-bottomed flask, and add acetic anhydride and
Add exactly 5 ml of pyridine test solution, attach a ground air cooler, immerse in an oil bath, and heat at 95-100°C for 1 hour to acetylate. After cooling, add 1 ml of water from above the air cooler, shake well, and heat in an oil bath for 10 minutes. After cooling, wash the air cooler and the deposits on the neck of the flask with 5 ml of neutralized ethanol. Titrate with 0.1N or 0.5N potassium hydroxide/ethanol solution (indicator: 1 ml of phenolphthalein reagent). Perform a blank test in the same manner and make corrections. Hydroxyl value = (a-b) N x 56.11 / amount of sample (g) +
C a: Consumption amount (ml) of potassium hydroxide/ethanol solution in blank test. b: Consumption amount (ml) of potassium hydroxide/ethanol solution when using the sample. C: Oxidation N: Normality of potassium hydroxide/ethanol solution. In addition, the glass transition point Tg of the present invention refers to "Mechanical Properties of Polymers" by LE Nielsen, translated by Nobuharu Onogi.
This is the Tg measured for general polymers as described on pages 11 to 35, and the same amount for copolymers.
This is the calculated Tg described on pages 26-27. That is, the Tg of the copolymer was calculated using the following formula. 1/Tg=W ₁ /Tg ₁ +W ₂ /Tg ₂ +...Wn/Tgn (however, W ₁ +W ₂ +...Wn=1) Here, Tg is the copolymer glass transition temperature and is converted to absolute temperature. calculate. W ₁ , W ₂ ...and
Wn is the weight fraction of each component. The Tg of the acrylic copolymer oligomer of the present invention is
The temperature must be below 20℃. If the Tg is too high, exceeding 20°C, the fluidity will be high and only a hard and brittle coating film with no elasticity will be obtained, which will easily cause cracking, which is not suitable. Further, the viscosity of the acrylic copolymer oligomer of the present invention is 100 to 200,000 cps, preferably 500 to 200,000 cps.
100,000 cps, particularly preferably 500 to 50,000 cps. If the viscosity is less than 100 cps, the pigment may settle or sag, making it impossible to obtain a smooth coating film.
If it exceeds 200,000cps, liquidity will be weak.
Pigment dispersion becomes poor and a solvent-free coating composition cannot be obtained, which is not suitable. The viscosity is a value measured at 25°C using a B-type viscometer (manufactured by Tokyo Keiki). The solvent-free coating composition of the present invention contains, in addition to the acrylic copolymer oligomer, at least one curing agent selected from the group of polyfunctional isocyanates and amino resins. Examples of the polyfunctional isocyanate used in the present invention include tolylene diisocyanate and its water additives and adducts, diphenylmethane diisocyanate and its water additives, triphenylmethane triisocyanate and its water additives, and hexamethylene diisocyanate. , xylylene diisocyanate and its water additive, isophorone diisocyanate, dianisidine diisocyanate, tolydine diisocyanate, blocked polyisocyanate in which isocyanate groups are blocked, and any mixtures thereof, but from the viewpoint of weather resistance, tolylene diisocyanate is preferred. Particularly preferred are water additives of hexamethylene diisocyanate, xylylene diisocyanate, and adducts of these isocyanates. These polyfunctional isocyanates are preferably blended in an amount of 0.7 to 1.5 reaction equivalents per equivalent of hydroxyl group in the acrylic copolymer oligomer. This is because the amount of polyfunctional isocyanate is
If it is 0.7 reaction equivalent or more, the stickiness will disappear,
This is because it has excellent gloss and hardness, and on the other hand, the amount of
When the reaction equivalent is 1.5 or less, the film becomes hard, has excellent flexibility, and has good adhesion to the object to be coated, which is preferable. After coating, the solvent-free coating composition of the present invention containing a polyfunctional isocyanate is cured at a temperature of 0 to 160°C, preferably 20 to 160°C. The curing time depends on the curing temperature, catalyst, etc., but is usually 50 hours or less, preferably about 3 seconds to 8 hours. Next, the amino resin used in the present invention includes etherified methylolmelamine resins, such as methylated methylolmelamine, ethylated methylolmelamine, butylated methylolmelamine,
isopropylated methylol melamine; etherified methylol urea resins, such as methylated methylol urea, ethylated methylol urea, butylated methylol urea; etherified urea melamine cocondensates;
Examples include methylated methylol urea melamine, ethylated methylol urea melamine, butylated methylol urea melamine; and any mixture thereof;
Methylated methylol melamine, which easily imparts hardness.
Particularly preferred is the use of ethylated methylolmelamine and butylated methylolmelamine. These amino resins are preferably blended in a proportion of 0.2 to 1.0 reaction equivalent per equivalent of hydroxyl group in the acrylic copolymer oligomer. This is because when the blending amount of amino resin is 0.2 reaction equivalent or more, stickiness is eliminated, the gloss and hardness are excellent, and the stain resistance is eliminated, whereas when the blending amount is 1.0 reaction equivalent or less, The membrane becomes hard,
Moreover, it is preferable because it has excellent flexibility and good adhesion to the object to be coated. The solvent-free coating composition of the present invention containing an amino resin has a temperature of 80 to 250°C, preferably 100 to 220°C after application.
Bake at a temperature of 2 to 120 minutes, preferably 5 to 60 minutes. The polyfunctional isocyanate and/or amino resin described above can be mixed with the acrylic copolymer oligomer using any conventionally known method, such as an ink mill, a grinder, a ribbon blender, a high-speed homomixer, etc. The solvent-free coating composition of the present invention generally contains a curing catalyst in addition to the acrylic copolymer oligomer and polyfunctional isocyanate or/and amino resin. As curing catalysts to be added to the solvent-free coating composition of the present invention, conventionally, amino resins, blends of amino resins and thermoplastic resins having functional groups (for example, coating resins such as melamine-alkyds and melamine-acrylics) have been used. Curing catalysts commonly used for curing, etc.), curing catalysts commonly used for accelerating curing of isocyanates, etc. can be used. Typical curing catalysts used in the present invention include organic acids and their salts,
For example, para-toluenesulfonic acid, phthalic anhydride,
Benzoic acid, benzenesulfonic acid, formic acid, acetic acid, itaconic acid, oxalic acid, maleic acid and their ammonium salts, lower amine salts, polyvalent metal salts, etc. For polyfunctional isocyanates, amines such as trimethylamine , triethylamine, tripropylamine, tributylamine, phenylamine, triethylenediamine: metal compounds such as stannath octoate, dibutyltin di-2-ethyhexoate, dibutyltin dilaurate, red-2-ethylenehexoate, sodium phenyl phenate, potassium Olate, bismuth nitrate, tetra(2-ethylhexyl) titanate, stannic chloride, ferric chloride, iron 2-ethylhexoate, cobalt 2-ethylhexoate, zinc naphthenate, antimony trichloride, etc. be. The amount of these curing catalysts used is
The total amount of the acrylic copolymer oligomer and at least one curing agent selected from the group of polyfunctional isocyanates and amino resins, that is, 2% by weight or less based on the total resin amount, preferably in the case of amino resins.
0.01 to 1% by weight, and in the case of polyfunctional isocyanates, 10 ppm to 1% by weight. The solvent-free coating composition of the present invention can further contain pigments and/or dyes that are commonly used in conventional coating compositions and others, if necessary. Examples of such pigments include red iron, yellow lead, navy blue, ultramarine blue, iron black, molybdenum red, zinc yellow,
Examples include inorganic pigments such as titanium oxide and organic pigments such as permanent red, lake red, resol red, pyrazolin red, hansa yellow 10G, phthalocyanine green, pigment green, and phthalocyanine blue.As dyes, for example, natural dyes such as eye, azo Examples include synthetic dyes such as dyes, anthraquinone dyes, indigoid dyes, sulfur dyes, phthalocyanine dyes, diphenylmethane dyes, and triphenylmethane dyes. There are no particular limitations on the amount of these pigments and/or dyes, but they are generally blended in an amount of 0 to 50% by weight, preferably 0 to 30% by weight, based on the solvent-free coating composition. The solvent-free coating composition of the present invention may further contain plasticizers such as phthalates, phosphates, epoxidized soybean oil, polyesters, and epoxys; lead salts, and metal soaps. UV absorbers such as amine-based, phenol-based, and benzotriazole-based stabilizers; anti-settling agents (anti-sagging agents) such as bentonite, silica, hydrogenated castor oil, and polymerized oil; Fungicides and insect repellents such as tribromusalicylanilide, ethylbenzylmethylalkylammonium, cyclohexylsulfamate, naphthoquinone derivatives, N-trichloromethylthiophthalimide, barium metaborate; fragrances; and the like can be blended. The amounts of these additives are the same as those commonly used in the past. The solvent-free coating composition of the present invention can be applied, for example, to the surface of objects to be coated, such as plastic, metal, wood, and other inorganic materials, by brush coating, spray coating, brush coating, etc.
It can be applied by dipping or the like, and then baked and cured at room temperature or in a hot air dryer. If necessary, a primer having compatibility with the surface of the object to be coated and the solvent-free coating composition may be applied to improve the adhesion of the coating film. Unlike organic solvent-based paints, the solvent-free paint composition of the present invention does not substantially contain any solvents, so it does not have a unique irritating odor and is non-polluting. Therefore, it can be suitably used for interior painting. It is smooth and glossy, and its oxygen permeability and other permeability are extremely low, so there is no mold growth, and it can withstand cold and heat cycles, making it resistant to repeated steam sterilization, making it extremely valuable as a paint especially for food factories and hospitals. It is something that exhibits useful value. Further, since the solvent-free coating composition of the present invention has a low viscosity, it is easy to prepare and handle, and since the pigment has good dispersibility, it can be colored in any desired color and has a high decorative design effect on the surface. The present invention will be explained in more detail below with reference to Examples. Reference Examples 1 to 9 A: Preparation of acrylic copolymer oligomer BMA MMA 2EHA 2HEA Benzoyl peroxide 30 parts by weight 10 〃 35 〃 25 〃 8 〃 t-Dodecymercaptan ethyl cellosolve 15 〃 150 〃 Dropping device, stirrer, reflux Place the mixture in a reactor equipped with a condenser and thermometer and raise the temperature to 110°C while stirring. After the temperature was raised, the monomer mixture shown above was continuously added dropwise over about 5 hours, and the reaction was continued for an additional 2 hours after the addition was completed. The obtained resin liquid was concentrated under reduced pressure to remove nonvolatile components.
Acrylic copolymer oligomer No. 1 of 99.5% was obtained. This acrylic copolymer oligomer No. 1 had a number average molecular weight of 5800, a hydroxyl value of 120, a Tg of -13°C, and a viscosity of 3600 cps. Acrylic copolymer oligomers No. 2 to No. 9 were prepared in the same manner. Table 1 shows the number average molecular weight, hydroxyl value, Tg, and viscosity of these acrylic copolymer oligomers.
The symbols used in the monomer composition column in Table 1 are as follows. AA: Acrylic acid MA: Methyl EA: Ethyl BA: Butyl 2FHA: 2-ethylhexyl 2HEA: 2-hydroxyethyl MMA: Methyl methacrylate EMA: Ethyl BMA: Butyl 2HEMA: 2-hydroxyethyl VAC: Vinyl acetate Examples 1 to 7 and Comparative Examples 1 to 4 B: Preparation of solvent-free paint Oligomer No. 1 Typeke R-930 Stannous naphthenate antifoaming agent 100 parts by weight 83 〃 0.002 〃 0.001 〃 Duranate 24A-100 39 〃 The above composition with total resin amount/pigment = 1/0.6 was thoroughly mixed with a kneading roll, and OH/
Add curing agent so that NCO = 1/1, Example 1
A solvent-free paint was created. In the same manner, solvent-free paints of Examples 2 to 7 and Comparative Examples 1 to 4 shown in Table 2 were prepared. The pigments and curing agents used are as follows. Taipek 7R-930: Manufactured by Shiraishi Sangyo Co., Ltd., titanium oxide. Duranate 24A-100: Manufactured by Asahi Kasei Corporation, hexamethylene diisocyanate adduct, non-volatile content 100%, viscosity 2000 cps, NCO 23%. Coronate AP: Manufactured by Nippon Polyurethane Co., Ltd., blocked tolylene diisocyanate adduct, powder, NCO: 12%.

[Table] All of the solvent-free paints of Examples 1 to 7 and Comparative Examples 1, 3, and 4 had good pigment dispersibility and exhibited excellent suitability for forming solvent-free paints. On the other hand, Comparative Example 2 had a high viscosity and poor pigment dispersibility, making it unsuitable for use as a solvent-free paint. C: Performance test of solvent-free paints The solvent-free paints of Examples 1 to 7, Comparative Examples 1 to 7, and Comparative Examples 1, 3, and 4 were tested on steel plates (JIS-C
-3141, Bt#137 treatment, thickness 0.3mm) with film thickness 30 ~
It was applied to a thickness of 35 microns and left to harden at room temperature for 5 days. Table 3 shows the results of measuring the physical properties of this coating film. However, Examples 6 and 7 and Comparative Example 4 were cured at 145°C for 30 minutes. The following test method was used to measure the physical properties of the coating film. 1) Hardness (pencil scratch test) Measured according to JIS-K-5440. 2) Adhesiveness Use a razor to spread the coating surface to the substrate by 1 mm.
100 1mm goblets were made, cellophane tape was pressed onto them, the tape was immediately removed, and the remaining number of goblets was examined. As for the determination, the larger the number remaining, the better the adhesion. 3) Flexibility Measured according to JIS-K-5440. 4) When extruded from the back of the test piece according to the Eriksen test method of JIS-B-7777, cracks, peeling,
Judgment was made when this occurred. 5) Gloss Measured at 60° gloss according to JIS-K-5440. 6) Water-based boiling resistance Judgment is made based on the state of blistering and peeling according to JIS-K-5440. 7) Cold/heat cycle test The coating surface was exposed to boiling water vapor for 10 minutes and then immersed in cold water (18-20℃) for 10 minutes.This test was repeated 10 times, and no cracks or loss of gloss occurred in the coating. Those with no defects were rated as ○, those with only cracks were rated as △, and those with cracks and reduced gloss were rated as ×. 8) O ₂ transmittance The solvent-free coating compositions of Examples 1 to 7 and Comparative Examples 3 to 4 were tested according to the method described in the above section "C: Performance test of solvent-free coatings" as described below. For the solvent-free coating compositions of Examples 8 to 12 and Comparative Example 7, films with a thickness of 15 microns were prepared according to the method described in "E: Performance test of solvent-free coatings," and ASTM−D1434−
Measure according to 58. Examples 8 to 12 and Comparative Examples 5 to 7 D: Preparation of solvent-free paint Oligomer No. 4 70 parts by weight Taipeiku R-930 60 〃 Nikaratsuku MW-30 30 〃 P-Toluenesulfonic acid 0.5 〃 Total amount of the above resin /pigment=1/0.6 was thoroughly mixed with a kneading roll to prepare a solvent-free paint of Example 8. In the same manner, solvent-free paints of Examples 9 to 12 and Comparative Examples 5 to 7 shown in Table 4 were prepared. The curing agent used was as follows. Nikaratsuku MW-30: Manufactured by Sanwa Chemical Co., Ltd., methylated methylolmelamine.

[Table] The solvent-free paints of Examples 8 to 12 and Comparative Examples 5 and 7 all showed good pigment dispersibility and excellent suitability for forming solvent-free paints.
Comparative Example 6 was unsuitable due to its high viscosity and poor pigment dispersibility. E: Performance test of solvent-free paint The solvent-free paint compositions of Examples 8 to 12 and Comparative Examples 5 and 7 described above were applied to a steel plate (JIS-C-3141, B ₁
#137 treatment, 0.3 mm thick) was applied to a film thickness of 30 to 35 microns and baked at 50°C for 20 minutes. Table 3 shows the results of measuring the physical properties of this coating film using the test method described above. As can be seen from Table 3, the coating films formed from the solvent-free coating compositions of the present invention not only exhibit excellent adhesion, but also boiling water resistance (water resistance); properties, cooling/heating cycles, Erichsen (flexibility); extremely low oxygen permeability (mildew resistance)
It shares excellent performance that cannot be obtained with conventional paints, and also has no solvent odor during painting, has high flexibility and Erichsen value, and is resistant to cold and hot cycles. It was especially effective as a paint for food factories, which require a low oxygen permeability and constantly sterilize the interior of the factory with steam and have high humidity. On the other hand, Comparative Examples 3 and 4 using acrylic copolymer oligomers with hydroxyl values outside the range of 80 to 350,
In Nos. 5 and 7, when the hydroxyl value was high, the adhesion was particularly poor, and when the hydroxyl value was low, the gloss, boiling water resistance, etc. were poor.

【table】

[Table] * indicates oligomer for comparative example.

【table】

Claims (1)

[Scope of Claims] 1 The following (a) and (b), (a) the following general formula [] and [], general formula (In the formula, R ₁ represents H or CH ₃ and R ₂ represents H or an alkyl group.) (In the formula, R ₃ represents H or CH ₃ and R ₄ represents an alkylene group.) Contains at least 80% by weight of a monomer compound represented by the following as a monomer unit, and has a monomer unit number average molecular weight of 500 to 8000, Hydroxyl value is 80-350
an acrylic copolymerized oligomer having a glass transition point of 20°C or less and a viscosity of 100 to 200,000 centipoise, and (b) at least one type of curing selected from the group of polyfunctional isocyanates and amino resins. A solvent-free coating composition comprising: 2 In the monomer compound of general formula [], R ₂
The solvent-free coating composition according to claim 1, wherein is H or an alkyl group having 1 to 8 carbon atoms. 3 In the monomer compound of general formula [], R ₄
The solvent-free coating composition according to claim 1 or 2, wherein is an alkylene group having 1 to 6 carbon atoms.