JP2016199717A - Temperature-sensitive polymer, coating composition containing the temperature-sensitive polymer and method for forming multilayer coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a temperature-sensitive polymer which shows temperature responsiveness having a lower critical solution temperature, and is present stably in a particulate state in water and/or an organic solvent, and to provide a coating composition which has excellent temperature responsiveness when the temperature-sensitive polymer is added as a fluidity adjusting agent to the coating composition.SOLUTION: The temperature-sensitive polymer is provided which shows temperature responsiveness having a lower critical solution temperature, and is present stably in a particulate state in water and/or an organic solvent, and in which a polymerizable unsaturated monomer constituting the polymer contains an N-substituted (meth)acrylamide derivative and/or vinyl methyl ether. The coating composition containing the temperature-sensitive polymer is also provided.SELECTED DRAWING: None

Description

The present invention shows a temperature-responsive polymer having a lower critical eutectic temperature and is present in a particle state in water and / or an organic solvent, containing the thermosensitive polymer The present invention relates to a coating composition and a method for forming a multilayer coating film using the coating composition.

The use of stimuli-responsive substances as industrially available functional materials has been widely studied.
Among them, there are many organic materials that are put to practical use, such as a leuco dye and a liquid crystal temperature display material having a heat display property in response to temperature, that is, a temperature-sensitive response, which is the most common stimulus form.

The temperature-responsive polymer is attracting attention as a temperature-sensitive viscosity regulator because it has a characteristic that the polymer solution has a uniform state at a certain temperature (lower critical solution temperature: LCST) or lower and causes aggregation at a certain temperature or higher. Development is underway for a wide range of applications such as paints, inks, resin solutions for films, cosmetics, magnet modifiers, and slurry for electrodes.

  Patent Document 1 discloses that a graft copolymer having temperature responsiveness and soluble in water at room temperature is used as a thickener in a coating material. However, since it is in a dissolved state in the paint, there are cases where the temperature sensitivity is weak and the thickening is insufficient. Patent Document 2 discloses that gel fine particles are synthesized by emulsion polymerization using a surfactant. However, when a highly water-soluble monomer is used, emulsion polymerization is difficult, and the temperature sensitive point may shift to the high temperature side depending on the type and amount of surfactant added. In Patent Document 3, an oxazoline compound is added to a temperature-sensitive gel fine particle dispersion obtained by polymerizing an alkyl (meth) acrylamide, a bifunctional or higher monomer, and an unsaturated carboxylic acid in a solvent, and the temperature-sensitive gel fine particles are added. A method of surface cross-linking is disclosed. However, when a highly water-soluble monomer is used, emulsion polymerization is difficult, and when it is stored at a high temperature for a long time, secondary aggregation may occur.

Table 2010-101196 JP 7-33224 A JP 2006-96831 A

The problem to be solved by the present invention is to obtain a temperature-sensitive polymer that exhibits temperature responsiveness and stably exists in water and / or an organic solvent, and controls the flow of the temperature-sensitive polymer. It is to obtain a coating composition having excellent temperature sensitivity when added as an agent.

  As a result of intensive studies to solve the above problems, the inventors have developed a temperature responsiveness having a lower critical eutectic temperature, and in a temperature-sensitive polymer existing in a particle state in water and / or an organic solvent. The present inventors have found that the above problems can be solved and have completed the present invention.

That is, the present invention relates to the following temperature-sensitive polymer, a coating composition containing the temperature-sensitive polymer, and a method for forming a multilayer coating film using the coating composition.
Item 1. A temperature-sensitive polymer that exhibits a temperature responsiveness having a lower critical eutectic temperature and exists in a particle state in water and / or an organic solvent, and is a polymerizable unsaturated component constituting the polymer A temperature-sensitive polymer, wherein the monomer contains an N-substituted (meth) acrylamide derivative and / or vinyl methyl ether.
Item 2. As the polymerizable unsaturated monomer constituting the polymer, 10 to 100% by mass of the polymerizable unsaturated monomer (A) in which the homopolymer exhibits the lower critical solution temperature, and the homopolymer does not exhibit the lower critical solution temperature. Item 2. The thermosensitive polymer according to Item 1, which contains 0 to 90% by mass of an unsaturated monomer (B).
Item 3. The polymerizable unsaturated monomer (B) in which the homopolymer does not exhibit a lower critical eutectic temperature is at least one polymerization selected from (meth) acrylamide, dimethyl (meth) acrylamide, hydroxyethyl (meth) acrylamide, and acryloylmorpholine. 3. The temperature-sensitive polymer as described in 2 above, wherein the temperature-sensitive polymer contains a polymerizable unsaturated monomer.
Item 4. Polymerization in which the polymerizable unsaturated monomer (B) in which the homopolymer does not exhibit the lower critical eutectic temperature contains the monomer (B-1) having two or more polymerizable unsaturated groups and constitutes a thermosensitive polymer. Item 4. The temperature-sensitive polymer according to Item 2 or 3, wherein the monomer (B-1) is contained in an amount of 0.01 to 5% by mass based on the total amount of the polymerizable unsaturated monomer.
Item 5. Items 1 to 3 above, wherein in water, the average particle size D1 is 300 nm or more at a temperature of 20 ° C., the average particle size D2 is 200 nm or less at a temperature of 80 ° C., and D1 / D2 is 3 or more. 5. The temperature-sensitive polymer according to any one of 4 above.
Item 6. When 15% by mass of the thermosensitive polymer is contained in water, the viscosity V1 at a temperature of 20 ° C. is 500 mPa · s or more, the viscosity V2 at a temperature of 80 ° C. is 200 mPa · s or less, and V1 / V2 The temperature-sensitive polymer according to any one of Items 1 to 5, wherein is 5 or more.
Item 7. A coating composition containing 0.5 to 10% by mass of the temperature-sensitive polymer according to any one of Items 1 to 6, based on the resin solid content mass.
Item 8. A coated article obtained by coating the coating composition according to Item 7 on an article to be coated.
Item 9. 8. A multilayer coating film forming method in which a primer coating, a base coating, and a clear coating are sequentially applied onto an object to be coated, and the resulting three-layer coating film is heated and cured simultaneously. A method for forming a multilayer coating film, which is a coating composition.
Item 10. A primer coating, a base coating, and a clear coating are sequentially applied onto an object to be coated, and in the method for forming a multilayer coating film in which three layers are heated and cured simultaneously, the base coating is the coating composition according to Item 7 above. A method for forming a multilayer coating film.
Item 11. In the method for forming a multilayer coating film in which a base coating and a clear coating are sequentially applied on an object to be coated, and two layers are heated and cured at the same time, the base coating is the coating composition described in Item 7 above. A method for forming a multilayer coating film.
Item 12. The coated article obtained by the multilayer coating-film formation method of any one of said items 9-11.

The temperature-sensitive polymer according to the present invention exhibits a temperature responsiveness having a lower critical eutectic temperature while maintaining good storage stability. Further, when the temperature-sensitive polymer is added to the coating composition as a viscosity modifier, the coating composition also exhibits temperature responsiveness, and excellent finish can be obtained.

Hereinafter, embodiments for carrying out the present invention will be described in detail.
It should be understood that the present invention is not limited to the following embodiments, and includes various modifications that are implemented without departing from the scope of the present invention.

In the present specification, “(meth) acrylate” means acrylate and / or methacrylate, and “(meth) acrylic acid” means acrylic acid and / or methacrylic acid. “(Meth) acryloyl” means acryloyl and / or methacryloyl. “(Meth) acrylamide” means acrylamide and / or methacrylamide.
The “polymerizable unsaturated monomer” means a monomer having a polymerizable unsaturated group capable of radical polymerization, and examples of the polymerizable unsaturated group include (meth) acryloyl group, acrylamide group, vinyl group. , Allyl group, (meth) acryloyloxy group, vinyl ether group and the like.
The number average molecular weight or the weight average molecular weight in the present specification is the number average molecular weight or the weight average molecular weight of polystyrene measured by a gel permeation chromatograph (manufactured by Tosoh Corporation, “HLC8120GPC”). It is a value converted based on the molecular weight. In this measurement, the columns are “TSKgel G-4000H × L”, “TSKgel G-3000H × L”, “TSKgel G-2500H × L”, “TSKgel G-2000H × L” (all trade names, Tosoh Corporation) The measurement conditions of mobile phase tetrahydrofuran, measurement temperature 40 ° C., flow rate 1 mL / min, detector RI were used.

Temperature-sensitive polymer The temperature-sensitive polymer of the present invention is a polymer that exhibits temperature responsiveness having a lower critical solution temperature and exists in a particle state in water and / or an organic solvent, and is N-substituted. It can be obtained by copolymerizing a polymerizable unsaturated monomer containing a (meth) acrylamide derivative and / or vinyl methyl ether.

  The “N-substituted (meth) acrylamide derivative” means N-alkylacrylamide, N-allylacrylamide, acryloylmorpholine, N-alkylmethacrylamide, N-allylmethacrylamide, N, N-dialkylacrylamide, N, N-diallyl. It is a general term for acrylamide, N-alkyl, N-allylacrylamide, N, N-dialkylmethacrylamide, N, N-diallylmethacrylamide, N-alkyl, N-allylmethacrylamide and their derivatives. Specifically, for example, N-methylacrylamide, N-butoxymethylacrylamide, N-ethylacrylamide, Nnpropylacrylamide, N-isopropylacrylamide, N-cyclopropylacrylamide, N-hydroxyethylacrylamide, N-methylolacrylamide Methyl ether, N-methylol acrylamide ethyl ether, N-methylol acrylamide propyl ether, N-methylol acrylamide butyl ether, acryloylmorpholine, diacetone acrylamide, N-methyl methacrylamide, N-butoxymethyl methacrylamide, N-ethyl methacrylamide, N -N-propyl methacrylamide, N-isopropyl methacrylamide, N-cyclopropyl methacrylamide, dye Seton methacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N-methyl, N-ethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylmethacrylamide, N, N-dimethylaminopropyl Acrylamide, N-methyl, N-ethylmethacrylamide and the like can be mentioned, and these can be used alone or in combination of two or more.

  In the present invention, the temperature sensitivity showing a lower critical solution temperature (LCST) of 40 ° C. or higher by radical copolymerization of an N-substituted (meth) acrylamide derivative and / or vinyl methyl ether and other polymerizable unsaturated monomer. A polymer can be synthesized.

  In the present invention, as the other polymerizable unsaturated monomer copolymerized with an N-substituted (meth) acrylamide derivative and / or vinyl methyl ether as necessary, a known polymerizable unsaturated monomer can be suitably used. Examples thereof include a monomer containing one polymerizable unsaturated group in the following molecule and a monomer having two or more polymerizable unsaturated groups.

  Examples of the monomer containing one polymerizable unsaturated group in the molecule include styrene, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl. (Meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) ) C1-24 alkyl (meth) acrylates such as acrylate; (meth) acrylic acid; hydroxyacrylates such as 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate Kill (meth) acrylate; Epoxy group-containing (meth) acrylate such as glycidyl (meth) acrylate and 3,4-epoxycyclohexylmethyl (meth) acrylate; N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylamino Aminoalkyl (meth) acrylates such as ethyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylate; 3-ethyl-3- (meth) acryloyloxymethyloxetane, 3-methyl-3- (meth) acryloyl Oxetane ring-containing (meth) acrylates such as oxymethyloxetane and 3-butyl-3- (meth) acryloyloxymethyloxetane; γ- (meth) acryloyloxypropyltrimethoxysilane, β- (meth) acryloyloxyethyltrimeth Alkoxysilyl group-containing (meth) acrylates such as silane; dimethylpolysiloxane-containing (meth) acrylates such as Cyraprene FM-0711 (manufactured by Chisso Corporation), hexafluoroisopropyl (meth) acrylate, perfluorooctylmethyl (meth) acrylate , Fluorine-containing (meth) acrylates such as perfluorooctylethyl (meth) acrylate, (meth) allylonitrile, (meth) acrylonitrile, (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, vinyltoluene, isocyanate group-containing (meta ) Acrylate and the like. These can be used alone or in combination of two or more.

  Examples of monomers having two or more polymerizable unsaturated groups include allyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3- Butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, Methylene bis (meth) acrylamide, ethylene bis (meth) acrylamide, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol di (meth) acrylate, 1,1,1-tri Hydroxymethylethane di (meth) acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxymethylpropane tri (meth) acrylate, triallyl isocyanurate, diallyl terephthalate, divinyl Examples include benzene. These can be used alone or in combination of two or more.

  Further, by mixing two or more polymerizable unsaturated monomers having functional groups that react with each other and reacting with each other before, during and / or after polymerization of the polymer, substantially 1 polymerizable unsaturated group is formed. It can be used as a monomer equivalent to a polymerizable unsaturated monomer having two or more in the molecule. As the combination of functional groups, any combination of functional groups that react with each other can be suitably used, but a combination of an acid group and a glycidyl group, an amino group and a glycidyl group, or a hydroxyl group and an isocyanate group is more preferable. Specific combinations of polymerizable unsaturated monomers include, for example, (meth) acrylic acid and glycidyl (meth) acrylate, (meth) acryloyloxyalkyl acid phosphate and glycidyl (meth) acrylate, (di) alkylaminoethyl (meth) ) Acrylate and glycidyl (meth) acrylate, hydroxyalkyl (meth) acrylate, and (meth) acryloyloxyalkyl isocyanate.

Furthermore, a reaction product of a polymerizable unsaturated monomer having a reactive functional group and a compound having two or more functional groups capable of reacting with the reactive functional group is synthesized, and the polymerizable unsaturated group is contained in one molecule. It can be suitably used as a polymerizable unsaturated monomer having two or more. Examples thereof include a reaction product of a glycidyl group-containing polymerizable unsaturated monomer and a polybasic acid component, a hydroxyl group-containing polymerizable unsaturated monomer and a polyfunctional isocyanate compound. Specific examples include a reaction product of glycidyl (meth) acrylate and adipic acid, a reaction product of hydroxyalkyl (meth) acrylate and hexamethylene diisocyanate, and the like.
These can be used alone or in combination of two or more.

  N-substituted (meth) acrylamide derivatives and / or vinyl methyl ether and other polymerizable unsaturated monomers can be classified into a monomer (A) whose homopolymer shows a lower critical solution temperature (LCST) and a monomer (B) which does not show a lower critical solution temperature (LCST). .

The vinyl methyl ether that can be contained as a constituent of the temperature-sensitive polymer of the present invention is a polymerizable unsaturated monomer in which the homopolymer exhibits a lower critical solution temperature (LCST). The N-substituted (meth) acrylamide derivative that can be contained as a constituent of a warm polymer is composed of a polymerizable unsaturated monomer having a lower critical solution temperature (LCST) and a lower critical solution temperature (LCST). There are polymerizable unsaturated monomers that do not exhibit
Examples of the N-substituted (meth) acrylamide derivative showing the lower critical solution temperature (LCST) include N-isopropylacrylamide (LCST is 30.9 ° C.), N-n propylacrylamide (LCST is 21.5 ° C.). And N-n-propylmethacrylamide (LCST is 28.0 ° C.), N, N-diethylacrylamide (LCST is 32.0 ° C.), etc. [Reference: Shoji Ito 46 (7), 437-443 (1989)]. Examples of N-substituted (meth) acrylamide derivatives that do not exhibit the lower critical eutectic temperature (LCST) include, for example, N, N-dimethyl (meth) acrylamide, hydroxyethyl (meth) acrylamide, acryloylmorpholine, N, N-dimethyl. Examples include aminopropylacrylamide. In addition, (meth) acrylamide does not show a lower critical solution temperature (LCST).
Moreover, as a monomer (A) which is a polymerizable unsaturated monomer other than the N-substituted (meth) acrylamide derivative and the homopolymer exhibits a lower critical solution temperature (LCST), 1- (1-oxo-2-propenyl)- Examples include piperidine and N-acryloylpiperidine.

  The temperature-sensitive polymer of the present invention comprises, as a polymerizable unsaturated monomer constituting the polymer, 10 to 100% by mass of a polymerizable unsaturated monomer (A) in which the homopolymer exhibits a lower critical solution temperature. It is preferable to contain 0 to 90% by mass of the polymerizable unsaturated monomer (B) that does not exhibit the lower critical eutectic temperature.

  The polymerizable unsaturated monomer constituting the thermosensitive polymer of the present invention includes a polymerizable unsaturated monomer (A) and a polymerizable unsaturated monomer in which the homopolymer does not exhibit a lower critical solution temperature (LCST). It is preferable to use in combination with the monomer (B). As content of the said polymerizable unsaturated monomer (A) and polymerizable unsaturated monomer (B), polymerizable unsaturated monomer (A) is the total amount of the polymerizable unsaturated monomer which comprises a thermosensitive polymer. As a reference, usually 10 to 100% by weight, preferably 20 to 90% by weight, more preferably 30 to 80% by weight, and a polymerizable unsaturated monomer (homopolymer not exhibiting a lower critical solution temperature (LCST)) ( B) is usually contained in an amount of 0 to 90% by mass, preferably 10 to 80% by mass, more preferably 20 to 70% by mass from the viewpoint of temperature sensitivity.

  In addition, the polymerizable unsaturated monomer (B) in which the homopolymer does not exhibit the lower critical eutectic temperature (LCST) is at least one polymerizable selected from dimethyl (meth) acrylamide, hydroxyethyl (meth) acrylamide, and acryloylmorpholine. An unsaturated monomer is preferred from the viewpoint of copolymerizability.

  Furthermore, the polymerizable unsaturated monomer (B) in which the homopolymer does not exhibit the lower critical eutectic temperature (LCST) contains a monomer (B-1) having at least two polymerizable unsaturated groups, The monomer (B-1) is usually 0.01 to 5% by mass, preferably 0.05 to 4% by mass, more preferably, based on the total amount of polymerizable unsaturated monomers constituting the temperature-sensitive polymer. Is preferably contained in an amount of 0.1 to 3% by mass from the viewpoint of temperature sensitivity.

  Generally, the lower critical solution temperature (LCST) of a temperature-sensitive polymer increases when the copolymerizable unsaturated monomer becomes hydrophilic (higher polarity) and decreases when it becomes hydrophobic (lower polarity). Therefore, the lower critical solution temperature (LCST) can be adjusted by the type and blending amount of the polymerizable unsaturated monomer constituting the thermosensitive polymer.

The lower critical solution temperature (LCST) of the thermosensitive polymer of the present invention is usually 30 to 80 ° C., preferably 34 to 75 ° C., more preferably 38 to 70 ° C.

Polymerization Method of Temperature Sensitive Polymer The method for polymerizing the temperature sensitive polymer of the present invention is not particularly limited, and may be performed by a radical polymerization method using a known radical polymerization initiator, chain transfer agent or the like. Examples include thermal polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization, and suspension polymerization, and photopolymerization using ultraviolet rays. In the temperature-sensitive polymer of the present invention, emulsion polymerization is preferable from the viewpoint of temperature-responsiveness.

  As emulsion polymerization, a method is known in which water is used as a dispersion medium, an organic solvent is used as a dispersed phase, a polymerizable unsaturated monomer is dissolved in the dispersed phase, and radical polymerization is performed in the dispersed phase. However, when a highly hydrophilic polymerizable unsaturated monomer is used, the polymerizable unsaturated monomer migrates from the dispersed phase (organic solvent) to the dispersion medium (water), and uniform polymer particles cannot be polymerized or during polymerization. In some cases, it gelled. Therefore, in the present invention, reverse phase emulsification in which a water-soluble polymerizable unsaturated monomer is dissolved in a dispersed phase using an organic solvent as a dispersion medium and water as a dispersed phase, and a polymer is obtained by radical polymerization in the dispersed phase. It is particularly preferable to use a polymerization method.

  As the reverse phase emulsion polymerization, for example, a water-soluble polymerizable unsaturated monomer is dissolved in water, and then a water-in-oil emulsion is formed in an organic solvent using a surfactant or the like, if desired. And the like (for example, JP-A-7-242702, JP-A-9-208802, JP-B 52-18224, JP-B 52-39417) and the like can be used.

  As the organic solvent used in the reverse emulsion polymerization method, known organic solvents can be used without limitation, but organic solvents having low polarity are preferable, for example, alkanes such as pentane, hexane, heptane, octane, nonane, decane, and undecane. And cycloalkanes such as cyclopentane, cyclohexane, cycloheptane and cyclooctane; aromatic and cyclic hydrocarbons such as benzene, toluene, xylene, decalin and naphthalene. Moreover, nonpolar oils, such as paraffin oil, can also be used. These can be used alone or in combination of two or more.

As the polymerization initiator, known ones can be used. For example, a water-soluble azo compound [for example, azobisamidinopropane (salt) [for example, 2,2′-azobis (2-methylpropionamidine) dihydro Chloride], azobiscyanovaleric acid (salt) and 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] (salt)], oil-soluble azo compounds (eg azobiscyano Valeronitrile, azobisisobutyronitrile and azobiscyclohexanecarbonitrile), water-soluble peroxides (eg hydrogen peroxide, peracetic acid and t-butyl peroxide), oil-soluble peroxides (eg benzoyl peroxide and cumene) Hydroxyperoxides) and inorganic peroxides (eg ammonium persulfate and sodium persulfate) ), And the like.
The above peroxide may be used as a redox initiator in combination with a reducing agent. Examples of the reducing agent include sulfites (for example, sodium sulfite), bisulfites (for example, sodium bisulfite), bisulfites (for example, bisulfite). Sodium, potassium bisulfite and ammonium bisulfite), reducing metal salts [eg iron (II) sulfate], tertiary amines [eg dimethylaminobenzoic acid (salt) and dimethylaminoethanol], amine complexes of transition metal salts [eg A pentamethylenehexamine complex of cobalt (III) chloride and a diethylenetriamine complex of copper (II) chloride] and an organic reducing agent (for example, ascorbic acid). In addition, the azo compound, peroxide and redox initiator may be used alone or in combination of two or more initiators.

  As the surfactant, known ones can be used, and examples thereof include nonionic, anionic, cationic and amphoteric ones. One kind can be used alone, or two or more kinds can be used in combination. .

  The temperature-sensitive polymer of the present invention that can be obtained in this manner has a large particle size and viscosity because the polymer particles exist in a relatively broad state when the temperature is lower than the lower critical solution temperature (LCST). Is expressed. And when it becomes temperature higher than a lower limit critical solution temperature (LCST), a polymer particle will become small and a viscosity will fall.

  Specifically, the temperature-sensitive polymer of the present invention has an average particle diameter D1 at a temperature of 20 ° C. in water of usually 300 nm or more, preferably 350 nm or more, more preferably 400 nm or more, and a temperature of 80 ° C. in water. The average particle diameter D2 is usually 200 nm or less, preferably 150 nm or less, more preferably 100 nm or less. Further, D1 / D2 is usually 3 or more, preferably 3.2 or more, and more preferably 3.5 or more.

  In the present specification, the average particle size of the thermosensitive polymer is a value measured at 20 ° C. after diluting with deionized water by a conventional method using a submicron particle size distribution measuring device. As the submicron particle size distribution measuring apparatus, for example, “COULTER N6 type” (trade name, manufactured by Beckman Coulter, Inc.) can be used.

  Further, when the thermosensitive polymer of the present invention contains 15% by mass of the thermosensitive polymer in water, the viscosity V1 measured using a B-type viscometer (conditions: temperature 20 ° C., rotation speed 60 rpm). Is usually 500 mPa · s or more, preferably 600 mPa · s or more, more preferably 700 mPa · s or more, and the viscosity V2 when the temperature is 80 ° C. is usually 200 mPa · s or less, preferably 150 mPa · s or less, more Preferably, it is 100 mPa · s or less. Moreover, V1 / V2 is 5 or more normally, Preferably it is 7 or more, More preferably, it is 9 or more.

The lower critical solution temperature (LCST) of the thermosensitive polymer can be determined by measurement. Conveniently, the viscosity of a dilute aqueous solution (concentration of about 1 to 10% by mass) of a temperature-sensitive polymer is measured while gradually raising the temperature from room temperature using a temperature-variable viscosity measuring device, and the viscosity decreases rapidly. Temperature, that is, the peak temperature of the differential viscosity curve, can be determined as the lower critical solution temperature.
When the temperature-sensitive polymer is transparent or translucent, it can be measured by a simpler method. The dilute aqueous solution is visually checked while the temperature is raised, and the cloud point temperature (the temperature at which the aqueous solution rapidly becomes cloudy due to the aggregation of the polymer) can be set as the lower critical solution temperature (LCST).

Method of using thermosensitive polymer The thermosensitive polymer of the present invention is a viscous liquid at room temperature, and when heated to a temperature higher than LCST (lower critical solution temperature), the viscosity is greatly reduced and the fluidity is increased. It has the characteristic that becomes high. A particularly preferred application of the temperature-sensitive polymer of the present invention is to use it as a viscosity adjusting agent for baking type paint or forced drying type paint. The temperature-sensitive polymer of the present invention is converted to a solid content of 100% by mass of the resin solid content of the paint, and is usually 0.5 to 10% by mass, preferably 0.6 to 8% by mass, more preferably 0.7. By blending ˜6% by mass, it prevents the so-called “sagging” that the viscosity of the applied paint is high and the paint film slips down on the vertical surface when applied at a temperature lower than the LCST (lower critical solution temperature). it can.

At the time of drying or heating, when the temperature is raised, the fluidity and smoothness of the surface occurs due to a sudden drop in viscosity before and after the desired temperature, and there are fine “spray eyes” in spray coating and slightly large uneven patterns caused by solvent volatilization. A certain "vortex pattern" etc. can be eliminated and a high finished coating surface can be obtained. Thus, it is possible to obtain a paint having both coating workability and finished surface finish. The paint in this case may be a one-component type or a multi-component type, and may be a lacquer type or a thermosetting type.

Coating composition The coating composition containing the thermosensitive polymer of the present invention is prepared by dissolving or dispersing the thermosensitive polymer, film-forming resin, curing agent, and the like in a solvent by a known method. Can be obtained by:

Examples of the film-forming resin include acrylic resins, polyester resins, epoxy resins, polyether resins, alkyd resins, urethane resins, silicone resins, polycarbonate resins, silicate resins, chlorine resins, fluorine resins, and composites thereof. Resin etc. are mentioned. These can be used alone or in combination of two or more.
Especially, it is preferable that it is at least 1 sort (s) chosen from an acrylic resin, a polyester resin, and a urethane resin, and it is more preferable that they are an acrylic resin and / or a polyester resin.

The acrylic resin can be obtained by copolymerizing a known polymerizable unsaturated monomer, but is different from the thermosensitive polymer in that it does not exhibit temperature responsiveness having a lower critical solution temperature. .
Usually, any polymerizable unsaturated monomer used in the synthesis of an acrylic resin can be used without particular limitation. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl ( Alkyl (meth) acrylates such as (meth) acrylate having 3 or less carbon atoms, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, octyl ( (Meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, Alkyl or cycloalkyl (meth) acrylate such as tilcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, tricyclodecanyl (meth) acrylate; isobornyl such as isobornyl (meth) acrylate Polymerizable unsaturated compounds having a group; polymerizable unsaturated compounds having an adamantyl group such as adamantyl (meth) acrylate; and aromatic ring-containing polymerizable unsaturated compounds such as benzyl (meth) acrylate, styrene, α-methylstyrene and vinyltoluene Monomer; (meth) such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate Monoesterified product of acrylic acid and C2-8 dihydric alcohol, ε-caprolactone modified product of monoesterified product of (meth) acrylic acid and C2-8 dihydric alcohol, N-hydroxymethyl Hydroxyl-containing polymerizable unsaturated monomers such as (meth) acrylamide, allyl alcohol, (meth) acrylate having a polyoxyalkylene chain having a hydroxyl group at the molecular end; (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyl Carboxyl group-containing polymerizable unsaturated monomers such as ethyl acrylate; (meth) acrylonitrile, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N- Dimethylaminopropyl (meth) acrylamide, glycidyl (medium A) Nitrogen-containing polymerizable unsaturated monomers not containing urethane bonds such as adducts of acrylates and amines; reaction products of isocyanate group-containing polymerizable unsaturated monomers and hydroxyl group-containing compounds or hydroxyl group-containing polymerizable unsaturated monomers Polymerizable monomers having a urethane bond such as a reaction product of an isocyanate group-containing compound; glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3 , 4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, and other epoxy group-containing polymerizable unsaturated monomers such as allyl glycidyl ether; having a polyoxyethylene chain whose molecular terminal is an alkoxy group (Meta) ak 2-acrylamido-2-methylpropane sulfonic acid, 2-sulfoethyl (meth) acrylate, allyl sulfonic acid, 4-styrene sulfonic acid, and the like, and polymerizable compounds having sulfonic acid groups such as sodium salt and ammonium salt of these sulfonic acids. Unsaturated monomer; polymerizable unsaturated monomer having a phosphate group such as 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, 2-methacryloyloxypropyl acid phosphate; Methoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxy Polymerizable unsaturated monomers having alkoxysilyl groups such as propyltriethoxysilane; perfluoroalkyl (meth) acrylates such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; fluorine such as fluoroolefin Polymerizable unsaturated monomer having a functionalized alkyl group; polymerizable unsaturated monomer having a photopolymerizable functional group such as a maleimide group; (meth) acrylate having a polyoxyethylene chain whose molecular end is an alkoxy group; allyl (meth) Acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri ( (Meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tetra (meta) ) Acrylate, glycerol di (meth) acrylate, 1,1,1-trishydroxymethylethane di (meth) acrylate, 1,1,1-trishydroxymethylethane tri (meth) acrylate, 1,1,1-trishydroxy Examples thereof include polymerizable unsaturated monomers having two or more polymerizable unsaturated groups in one molecule such as methylpropane tri (meth) acrylate, triallyl isocyanurate, diallyl terephthalate, and divinylbenzene. These can be used alone or in combination of two or more.

  A conventionally well-known method can be used for the polymerization method of an acrylic resin. For example, it can be produced by solution polymerization of a polymerizable unsaturated monomer in an organic solvent, but is not limited thereto, and for example, bulk polymerization, emulsion polymerization, suspension polymerization, or the like may be used. When performing solution polymerization, it may be continuous polymerization or batch polymerization, and the polymerizable unsaturated monomer may be charged all at once, may be charged separately, or may be added continuously or intermittently. Good.

  The polyester resin can be usually produced by an esterification reaction or an ester exchange reaction between an acid component and an alcohol component.

  As said acid component, the compound normally used as an acid component can be used at the time of manufacture of a polyester resin. Examples of the acid component include an aliphatic polybasic acid, an alicyclic polybasic acid, an aromatic polybasic acid, and the like.

  The aliphatic polybasic acid is generally an aliphatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aliphatic compound, and an esterified product of the aliphatic compound. Examples of the aliphatic polybasic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassic acid, octadecanedioic acid, citric acid, butane. Aliphatic polyvalent carboxylic acids such as tetracarboxylic acid; anhydrides of the aliphatic polyvalent carboxylic acids; and esterified products of lower alkyl having about 1 to 4 carbon atoms of the aliphatic polyvalent carboxylic acids. The above aliphatic polybasic acids can be used alone or in combination of two or more.

  As the aliphatic polybasic acid, it is particularly preferable to use adipic acid and / or adipic anhydride from the viewpoints of smoothness and sharpness of the resulting coating film.

The alicyclic polybasic acid is generally a compound having one or more alicyclic structures and two or more carboxyl groups in one molecule, an acid anhydride of the compound, and an esterified product of the compound. The alicyclic structure is mainly a 4- to 6-membered ring structure. Examples of the alicyclic polybasic acid include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-1 , 2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,3,5-cyclohexanetricarboxylic acid and other alicyclic polycarboxylic acids; An anhydride of a cyclic polyvalent carboxylic acid; an esterified product of a lower alkyl having about 1 to 4 carbon atoms of the alicyclic polyvalent carboxylic acid. The said alicyclic polybasic acid can be used individually by 1 type or in combination of 2 or more types.

  Examples of the alicyclic polybasic acid include 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid anhydride, 1,3-cyclohexanedicarboxylic acid, from the viewpoint of smoothness and sharpness of the resulting coating film. 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid anhydride are preferably used, among which 1,2-cyclohexanedicarboxylic acid and / or Alternatively, it is more preferable to use 1,2-cyclohexanedicarboxylic acid anhydride.

  The aromatic polybasic acid is generally an aromatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aromatic compound, and an esterified product of the aromatic compound, for example, phthalic acid , Isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, trimellitic acid, pyromellitic acid and other aromatic polycarboxylic acids; anhydrides of the aromatic polycarboxylic acids; aromatics Examples thereof include esterified products of lower alkyl having about 1 to 4 carbon atoms of polyvalent carboxylic acid. The aromatic polybasic acids can be used alone or in combination of two or more.

  As the aromatic polybasic acid, it is preferable to use phthalic acid, phthalic anhydride, isophthalic acid, trimellitic acid, or trimellitic anhydride.

  Moreover, acid components other than the said aliphatic polybasic acid, alicyclic polybasic acid, and aromatic polybasic acid can also be used. Such acid component is not particularly limited, for example, coconut oil fatty acid, cottonseed oil fatty acid, hemp seed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, tall oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, rapeseed oil fatty acid, Fatty acids such as castor oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid; lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexane Examples thereof include monocarboxylic acids such as acid and 10-phenyloctadecanoic acid; hydroxycarboxylic acids such as lactic acid, 3-hydroxybutanoic acid, and 3-hydroxy-4-ethoxybenzoic acid. These acid components can be used alone or in combination of two or more.

  As said alcohol component, the polyhydric alcohol which has a 2 or more hydroxyl group in 1 molecule can be used conveniently. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3 -Butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,2-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1, 2-pentanediol, 1,5-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene glycol, 3-methyl-4,3-pentanediol, 3-methyl-1,5-pentanediol, 2, , 4-Trimethyl-1,3-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4 hexanediol, 2,5-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol Dihydric alcohols such as tricyclodecane dimethanol, hydroxypivalic acid neopentyl glycol ester, hydrogenated bisphenol A, hydrogenated bisphenol F, and dimethylolpropionic acid; lactone compounds such as ε-caprolactone are added to these dihydric alcohols Polylactone diols; ester diol compounds such as bis (hydroxyethyl) terephthalate; alkylene oxide adducts of bisphenol A, polyethers such as polyethylene glycol, polypropylene glycol, polybutylene glycol Diol compound; glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol, dipentaerythritol, tris (2-hydroxyethyl) isocyanuric acid, sorbitol, mannitol, etc. A trilactone or higher alcohol; a polylactone polyol compound obtained by adding a lactone compound such as ε-caprolactone to the trihydric or higher alcohol; a fatty acid esterified product of glycerin, and the like.

  The method for producing the polyester resin is not particularly limited, and can be performed according to a usual method. For example, the acid component and the alcohol component are heated in a nitrogen stream at about 150 to 250 ° C. for about 5 to 10 hours, and a method of performing esterification reaction or transesterification reaction of the acid component and alcohol component is performed. Resin can be manufactured.

  When the acid component and the alcohol component are esterified or transesterified, they may be added to the reaction vessel at one time, or one or both may be added in several portions. .

  In the esterification or transesterification reaction, as a catalyst for promoting the reaction, dibutyltin oxide, antimony trioxide, zinc acetate, manganese acetate, cobalt acetate, calcium acetate, lead acetate, tetrabutyl titanate, tetraisopropyl A catalyst known per se, such as titanate, can be used.

  The polyester resin can be modified with a fatty acid, a monoepoxy compound, a polyisocyanate compound or the like during or after preparation of the resin.

  The said hardening | curing agent is a compound which can harden the coating composition of this invention by reacting with functional groups, such as a hydroxyl group in a film forming resin, a carboxyl group, and an epoxy group. Examples of the curing agent include amino resins, polyisocyanate compounds, blocked polyisocyanate compounds, epoxy group-containing compounds, carboxyl group-containing compounds, carbodiimide group-containing compounds, and the like. Of these, amino resins capable of reacting with hydroxyl groups, polyisocyanate compounds and blocked polyisocyanate compounds; carbodiimide group-containing compounds capable of reacting with carboxyl groups are preferred. Of these, amino resins and blocked polyisocyanate compounds are preferred, and amino resins are more preferred. A hardening | curing agent can be used individually by 1 type or in combination of 2 or more types.

  As said amino resin, the partial methylolation amino resin obtained by reaction of an amino component and an aldehyde component, or a complete methylolation amino resin can be used. Examples of the amino component include melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, dicyandiamide and the like. Examples of the aldehyde component include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. Moreover, what methylated the methylol group of the said methylolated amino resin partially or completely with suitable alcohol can also be used. Examples of the alcohol used for etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, and 2-ethylhexanol.

  As the amino resin, a melamine resin is preferable. In particular, methyl ether melamine resins in which methylol groups of partially or fully methylolated melamine resins are partially or completely etherified with methyl alcohol, methylol groups of partially or fully methylolated melamine resins are partially or completely with butyl alcohol. Preferred is a methyl-butyl mixed etherified melamine resin in which the methylol group of a partially or completely methylolated melamine resin is partially or completely etherified with methyl alcohol and butyl alcohol. Etherified melamine resins are more preferred.

As said solvent, a well-known thing can be used and water, an organic solvent, or its mixture can be mentioned. Examples of the organic solvent include hydrocarbon solvents such as n-butane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane and cyclobutane; aromatic solvents such as toluene and xylene; methyl isobutyl ketone and the like Ketone solvents; ether solvents such as n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol; ethyl acetate, n-butyl acetate, isobutyl acetate, Ester solvents such as ethylene glycol monomethyl ether acetate and butyl carbitol acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone; Alcohol solvents such as butanol, isopropanol, n-butanol, sec-butanol, isobutanol, etc .; Examide (trade name, manufactured by Idemitsu Kosan Co., Ltd.), N, N-dimethylformamide, N, N-dimethylacetamide, N- Conventionally known solvents such as amide solvents such as methylformamide, N-methylacetamide, N-methylpropioamide and N-methyl-2-pyrrolidone can be exemplified. These can be used alone or in combination of two or more.
Especially, it is preferable to contain water and / or a hydrophilic organic solvent as a solvent from a viewpoint which can make viscosity express strongly with the temperature-sensitive polymer of this invention in a coating composition. The hydrophilic organic solvent is not particularly limited as long as it is soluble in water, and examples thereof include the alcohol solvents, the ether solvents, and the amide solvents.

  Moreover, it is preferable that it is about 5-70 mass%, and, as for solid content of the coating composition of this invention, it is more preferable that it is about 15-60 mass%.

  In general, a paint obtained by dispersing and / or dissolving a film-forming resin, a pigment, or the like in water or a medium containing water as a main component (aqueous medium) is called an aqueous paint, and is compared with an organic solvent-type paint. The

  If necessary, the coating composition of the present invention may further include, for example, a luster pigment, a color pigment, an extender pigment, a rust inhibitor, a curing catalyst, an ultraviolet absorber, a light stabilizer, a pigment dispersant, a neutralizer, an interface. Additives for paints such as activators, antifoaming agents, plasticizers, surface conditioners, anti-settling agents and preservatives can be contained.

  Examples of the bright pigment include aluminum (including vapor-deposited aluminum), copper, zinc, brass, nickel, aluminum oxide, mica, titanium oxide or iron oxide coated with titanium oxide or iron oxide. And mica. These glitter pigments can be used alone or in combination of two or more. These glitter pigments are preferably in the form of flakes. As the bright pigment, aluminum, mica, aluminum oxide coated with titanium oxide or iron oxide, mica coated with titanium oxide or iron oxide is preferable, and aluminum is more preferable.

  The flake-like glitter pigment has a longitudinal dimension of usually about 1 to 100 μm, preferably about 5 to 40 μm, and a thickness of usually about 0.001 to 5 μm, preferably about 0.01 to 2 μm. Can be suitably used.

  Examples of the color pigment include titanium oxide, zinc white, carbon black, molybdenum red, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindoline pigment, selenium pigment, and perylene pigment. , Dioxazine pigments, diketopyrrolopyrrole pigments, and the like. These color pigments can be used alone or in combination of two or more.

  Examples of the extender pigment include talc, clay, kaolin, barita, barium sulfate, barium carbonate, calcium carbonate, silica, and alumina white.

The coating composition of the present invention contains the above temperature-sensitive polymer as a viscosity modifier in an amount of usually 0.5 to 10% by mass, preferably 0.6 to 8% by mass, more preferably 0.7 to 6% by mass. It is preferable to do.
Further, if necessary, it is also possible to use a viscosity modifier other than the temperature-sensitive polymer of the present invention in combination. Examples of the viscosity modifier other than the temperature-sensitive polymer include silicates and metals. Inorganic thickeners such as silicate, montmorillonite and colloidal alumina; copolymers of (meth) acrylic acid and (meth) acrylic acid esters, polyacrylic acid not showing temperature responsiveness such as sodium polyacrylate System thickener: It has a hydrophilic part and a hydrophobic part in one molecule, and in the aqueous medium, the hydrophobic part is adsorbed on the surface of the pigment or emulsion particles in the paint, or the hydrophobic parts are An associative thickener that effectively increases the viscosity by associating; a thickening agent of a fibrous derivative such as carboxymethylcellulose, methylcellulose, hydroxyethylcellulose; casein, sodium caseinate Protein thickeners such as ammonium caseinate; Alginate thickeners such as sodium alginate; Polyvinyl thickeners such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl benzyl ether copolymers; Pluronic polyethers, polyether dialkyl esters, Polyether thickeners such as polyether dialkyl ethers and polyether epoxy modified products; maleic anhydride copolymer thickeners such as vinyl methyl ether-maleic anhydride copolymer partial esters; polyamide amine salts, etc. Examples thereof include a polyamide thickener.

As an appropriate viscosity range of the coating composition of the present invention, the viscosity at 1,000 sec-1 when the shear rate is changed from 0.0001 sec-1 to 10,000 sec-1 at a measurement temperature of 20 ° C. It is usually 1.0 Pa · sec or less, preferably 0.01 to 0.5 Pa · sec. The viscosity at 0.1 sec-1 when the shear rate is changed from 0.0001 sec-1 to 10,000 sec-1 is usually within a range of 5 to 200 Pa · sec, preferably 10 to 100 Pa · sec. Preferably it is. The viscosity can be measured using a viscoelasticity measuring device. As the viscoelasticity measuring device, for example, HAAKE RheoStress RS150 (trade name, manufactured by HAAKE) can be used.

Coating Film Forming Method A coating composition containing the thermosensitive polymer of the present invention can form a coating film having an excellent appearance by coating on various objects to be coated.

Coating Material The coating composition containing the thermosensitive polymer of the present invention can be applied to various coating materials. Examples of the coating material include those outside automobile bodies such as passenger cars, trucks, motorcycles, and buses. Plate parts; automobile parts; outer plate parts of home electric products such as mobile phones and audio devices.

  The material of these objects to be coated is not particularly limited. For example, metal materials such as iron, aluminum, brass, copper, tinplate, stainless steel, galvanized steel, zinc alloy (Zn-Al, ZnNi, Zn-Fe, etc.) plated steel; polyethylene resin, polypropylene resin, acrylonitrile-butadiene- Styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin and other plastic materials such as various FRPs; glass, cement, concrete and other inorganic materials; wood; paper, Examples thereof include fiber materials such as cloth. Of these, metal materials and plastic materials are preferred.

  The object to be coated may be a metal surface of the metal material or a vehicle body formed from the metal material, and may be subjected to surface treatment such as phosphate treatment, chromate treatment, complex oxide treatment, A coating film may be formed thereon.

As an object to be coated, a surface treatment is applied to the substrate as necessary, an undercoat film is formed thereon, and an intermediate coat film is formed on the undercoat film. Etc. The undercoat coating film is preferably a coating film formed of an electrodeposition paint, preferably a cationic electrodeposition paint.

Coating method After coating a coating composition containing the thermosensitive polymer of the present invention on an object to form a wet coating film (uncured coating film), the wet coating film is cured, Can be formed.
In the present invention, the cured coating film refers to a cured and dried state defined in JIS K 5600-1-1 (2004), that is, a fingerprint on the coating surface by strongly sandwiching the center of the coating surface between the thumb and the index finger. The coating film is in a state where no dent is caused, the movement of the coating film is not felt, and the center of the coating surface is rapidly rubbed with a fingertip so that no mark is left on the coating surface. On the other hand, an uncured coating film is a state in which the coating film has not reached the above-mentioned cured and dried state, and includes a dry-to-touch state and a semi-cured and dried state defined in JIS K 5600-1-1.

  The coating method of the coating composition of the present invention is not particularly limited, and examples thereof include air spray coating, airless spray coating, rotary atomization coating, curtain coat coating, etc., and wet coating films are formed by these coating methods. can do. Of these, air spray coating or rotary atomization coating is preferred from the viewpoints of smoothness, sharpness, flip-flop properties, and the like of the resulting coating film. Moreover, you may apply electrostatic at the time of coating as needed.

The coating composition of the present invention is a case where a multilayer coating film comprising a primer coating film, a base coating film and a clear coating film is formed on an object to be coated by a three-coat one-bake method (3C1B), or When a multi-layer coating film composed of a clear coating film is formed by a two-coat one-bake method (2C1B), it can be suitably used as a paint for the primer coating film and / or the base coating film. The multilayer coating film forming method in this case can be performed according to the following method I or method II.

Method I
(1) A process of forming a primer coating film by applying a primer paint to an object to be coated,
(2) A step of applying a base coating on the uncured primer coating to form a base coating,
(3) A step of applying a clear coating on the uncured base coating to form a clear coating; and (4) the uncured primer coating, the uncured base coating and the uncured clear. A method for forming a multilayer coating film comprising a step of simultaneously heating and curing a coating film, wherein the primer coating composition and / or the base coating composition is a coating composition containing the thermosensitive polymer of the present invention

When the coating composition containing the temperature-sensitive polymer of the present invention is applied by the above-mentioned Method I 3-coat 1-bake method (3C1B), the coating thickness of the primer coating is usually 3 to 50 μm as a cured film thickness. The degree is preferable, about 5 to 30 μm is more preferable, and about 10 to 25 μm is further preferable. Moreover, the coating film thickness of the base paint is preferably about 1 to 30 μm, more preferably about 3 to 25 μm, and still more preferably about 5 to 20 μm as the cured film thickness. The coating thickness of the clear coating is usually preferably about 10 to 80 μm, more preferably about 15 to 60 μm, and still more preferably about 20 to 45 μm as a cured film thickness.

  In the above method I, after applying the primer paint and / or the base paint, preheating, air blowing, etc. may be performed under heating conditions in which the coating film is not substantially cured from the viewpoint of preventing the occurrence of coating film defects such as armpits. it can. Moreover, after the application of the clear coating, an interval of about 1 to 60 minutes can be provided at room temperature or preheating can be performed at about 40 to 80 ° C. for about 1 to 60 minutes as necessary.

Heat curing of the uncured primer coating, uncured base coating, and uncured clear coating multi-layer coating can be performed by a known heating means. The heating temperature is preferably higher than the lower critical solution temperature (LCST) of the thermosensitive polymer of the present invention, more preferably about 80 to 180 ° C, still more preferably about 100 to 170 ° C, and about 120 to 160 ° C. Is more particularly preferred. The heating time is preferably about 10 to 60 minutes, and more preferably about 20 to 40 minutes. By this heating, the three-layer coating film of the primer coating film, the base coating film, and the clear coating film can be simultaneously cured.

Method II
(1) A step of applying a paint (base paint) containing the temperature-sensitive polymer of the present invention to an article to form a base coating film,
(2) A step of applying a clear coating onto the uncured base coating to form a clear coating; and (3) heating the uncured base coating and the uncured clear coating. A multilayer coating film forming method comprising a step of simultaneously curing both coating films.

  When the coating composition (base coating composition) containing the temperature-sensitive polymer of the present invention is applied by the above-mentioned method II 2-coat 1-bake method (2C1B), the coating thickness of the base paint is a cured film. The thickness is preferably about 3 to 40 μm, more preferably about 5 to 30 μm, still more preferably about 8 to 25 μm, and still more preferably about 10 to 18 μm. The coating thickness of the clear coating is preferably about 10 to 80 μm, more preferably about 15 to 60 μm, and still more preferably about 20 to 45 μm as the cured film thickness.

  Further, in the method II, after the base paint is applied, the above-described preheating, air blowing, etc. can be performed under heating conditions in which the coating film is not substantially cured from the viewpoint of preventing the occurrence of coating film defects such as armpits. . Moreover, after the application of the clear coating, an interval of about 1 to 60 minutes can be provided at room temperature or preheating can be performed at about 40 to 80 ° C. for about 1 to 60 minutes as necessary.

Curing of the base coating film and the clear coating film can be performed by a known heating means. The heating temperature is preferably higher than the lower critical solution temperature (LCST) of the thermosensitive polymer of the present invention, more preferably about 80 to 180 ° C, still more preferably about 100 to 170 ° C, and about 120 to 160 ° C. Is more particularly preferred. The heating time is preferably about 10 to 60 minutes, and more preferably about 20 to 40 minutes. By this heating, both the base coating film and the clear coating film can be cured simultaneously.

  As the clear paint used in the above methods I to II, any known thermosetting clear paint composition can be used. Examples thereof include a film-forming resin having a crosslinkable functional group and an organic solvent-type thermosetting coating composition containing a crosslinking agent, an aqueous thermosetting coating composition, a powder thermosetting coating composition, and the like. .

  Examples of the crosslinkable functional group possessed by the film-forming resin include a carboxyl group, a hydroxyl group, an epoxy group, and a silanol group. Examples of the film-forming resin include acrylic resin, polyester resin, alkyd resin, urethane resin, epoxy resin, and fluorine resin. Examples of the crosslinking agent include polyisocyanate compounds, blocked polyisocyanate compounds, melamine resins, urea resins, carboxyl group-containing compounds, carboxyl group-containing resins, epoxy group-containing resins, and epoxy group-containing compounds.

  Examples of combinations of the film-forming resin / crosslinking agent of the clear coating composition include carboxyl group-containing resin / epoxy group-containing resin, hydroxyl group-containing resin / polyisocyanate compound, hydroxyl group-containing resin / blocked polyisocyanate compound, hydroxyl group-containing resin / melamine Resins are preferred.

  The clear coating composition may be a one-component paint or a multi-component paint such as a two-component urethane resin paint.

  In addition, the clear coating composition can contain, if necessary, a coloring pigment, a bright pigment, a dye and the like to such an extent that the transparency is not hindered, and further an extender pigment, an ultraviolet absorber, a light stabilizer, An antifoaming agent, a thickener, a rust inhibitor, a surface conditioner, and the like can be appropriately contained.

In the above methods I to II, the primer paint, the base paint, and the clear paint can be applied by a known method such as air spray coating, airless spray coating, and rotary atomization coating.

Hereinafter, the present invention will be described more specifically with reference to production examples, examples and comparative examples. However, the present invention is not limited to these. In each example, “parts” and “%” are based on mass unless otherwise specified. Moreover, the film thickness of a coating film is based on a cured coating film.

Production Example 1 of thermosensitive polymer
A four-necked flask equipped with a thermometer, nitrogen blowing tube, reflux cooling tower, stirrer, and dropping funnel is charged with 98.9 g of N-isopropylacrylamide, 0.1 g of methylenebisacrylamide, 1 g of acrylic acid, and 100 g of deionized water. Stir. After confirming that the mixed solution is dissolved and uniform, the pH is adjusted to 6.5 using a 10% NaOH aqueous solution. The mixture is stirred for 1 hour while blowing 100 ml of nitrogen per minute from the submerged nitrogen blowing tube. While continuing nitrogen blowing, 5% ammonium persulfate aqueous solution (5.8 g) is added and stirred for 5 minutes. A solution obtained by dissolving 40 g of EMALEX 503 (trade name, manufactured by Nippon Emulsion Co., Ltd., emulsifier, polyoxyethylene oleyl ether) in 400 g of n-hexane is added, and the mixture is further stirred for 30 minutes. The mixture is cooled to 10 ° C. or lower using ice water, and 7.3 g of a 2% aqueous sodium hydrogen sulfite solution is added dropwise over 30 minutes. During the dropping, the dropping speed is adjusted so that the liquid temperature does not exceed 20 ° C. due to heat generated by the reaction.
After completion of dropping, the mixture is stirred for 15 minutes while maintaining at 10 ° C. or lower. 2.9 g of 5% aqueous ammonium persulfate solution is added, and 3.6 g of 2% aqueous sodium hydrogen sulfite solution is added dropwise over 5 minutes.
After completion of the dropping, stirring was continued for 15 minutes to obtain a reverse phase emulsion polymerization dispersion having a solid content of 15%.
Next, while strongly stirring 300 g of acetone, 100 g of the obtained reverse phase emulsion polymerization dispersion 1 was added with stirring. The solvent and the emulsifier were removed by the gradient method, and the resulting precipitate was put into 100 g of deionized water. By stirring at room temperature for 1 hour, a thermosensitive polymer RC-1 having a solid content of 15% was obtained.

Examples 2 to 24 and Comparative Examples 1 to 3
Thermosensitive polymers RC-2 to RC-27 were obtained in the same manner except that the monomer composition of Example 1 was changed to the composition shown in Table 1 below.
In addition, the particle diameter, viscosity, and lower critical solution temperature (LCST) were measured by the method described later, and are shown in the table.

Comparative Example 4
A four-necked flask equipped with a thermometer, a nitrogen blowing tube, a reflux cooling tower, a stirrer, and a dropping funnel was charged with 400 g of deionized water, and stirred for 1 hour while blowing nitrogen at 100 ml / min from the submerged nitrogen blowing tube. After charging 10 g of Newcol 707SF (trade name, manufactured by Nippon Emulsifier Co., Ltd., an anionic surfactant having a polyoxyethylene chain, non-volatile content of 30%) and confirming that it was uniform, the temperature was gradually raised to 80 ° C. By adding dropwise an aqueous solution prepared by dissolving 49 g of N-isopropylacrylamide, 49.9 g of dimethylacrylamide, 0.1 g of methylenebisacrylamide, 1 g of acrylic acid, and 2 g of ammonium persulfate in 100 g of deionized water over 2 hours, Although an attempt was made to synthesize a temperature-sensitive polymer by the emulsion polymerization method, the viscosity of the dispersion in the flask increased to a gel state in about 1 hour after the start of dropping, and the desired polymer was not obtained. .

In addition, since the temperature-sensitive polymer RC-27 of Comparative Example 3 was not in a particle state at room temperature, the particle diameter and the like could not be measured.
Moreover, what is described as “above” exceeds the measurable value.
The abbreviations in the table have the following meanings.
NIPAM: N-isopropylacrylamide,
DEAA: N, N-diethylacrylamide,
DMAA: dimethylacrylamide,
HEAA: hydroxyethylacrylamide,
ACMO: acryloylmorpholine,
MBAAm: methylenebisacrylamide,
1,6-HDDA: 1,6-hexanediol diacrylate,
EDMA: ethylene glycol dimethacrylate,
Aam: acrylamide,
nBA: n-butyl acrylate,
AAc: acrylic acid,
HEA: 2-hydroxyethyl acrylate.

Evaluation test <particle size>
The obtained temperature-sensitive polymer was diluted to a measurable concentration with deionized water, and the particle size was measured using a COULTER N6 type (trade name, manufactured by Beckman Coulter, submicron particle size distribution analyzer). (Measured at 20 ° C and 80 ° C)
<Viscosity>
The viscosity of the obtained temperature-sensitive polymer was measured with a B-type viscometer (trade name, RE100L viscometer, manufactured by Toki Sangyo Co., Ltd.). (Measured at 20 ° C and 80 ° C)
<Lower critical solution temperature (LCST)>
The obtained temperature-sensitive polymer is diluted with deionized water to a solid content of 5%, and then gradually warmed up from room temperature to visually check the transparency of the aqueous solution, and the cloud point temperature (the polymer agglomeration occurs) The lower critical solution temperature (LCST), which is the temperature at which the aqueous solution becomes turbid, was measured.

Production and production example 1 of water-dispersible acrylic resin XA
In a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, nitrogen introduction tube and dropping device, 120 parts of deionized water and Adekaria soap SR-1025 (trade name, manufactured by ADEKA, emulsifier, active ingredient 25 %) 0.8 part was charged, stirred and mixed in a nitrogen stream, and heated to 80 ° C. Next, 5% of the total amount of the monomer emulsion for core part below and 2.5 parts of a 6% ammonium persulfate aqueous solution were introduced into the reaction vessel and maintained at 80 ° C. for 15 minutes. Then, the remainder of the monomer emulsion for core part was dropped into a reaction vessel maintained at the same temperature over 3 hours, and aging was performed for 1 hour after the completion of the dropping. Next, the following monomer emulsion for shell part was added dropwise over 1 hour and aged for 1 hour, and then cooled to 30 ° C. while gradually adding 3.8 parts of 5% 2- (dimethylamino) ethanol aqueous solution to the reaction vessel. Then, it was discharged while being filtered through a 100 mesh nylon cloth to obtain an aqueous dispersion of an aqueous dispersible acrylic resin XA having an average particle size of 100 nm and a solid content of 30%. The water-dispersible acrylic resin XA had an acid value of 24 mgKOH / g and a hydroxyl value of 11 mgKOH / g.

  Monomer emulsion for core part: 54 parts of deionized water, 3.1 parts of Adeka Soap SR-1025, 2.3 parts of allyl methacrylate, 12.3 parts of styrene, 31.2 parts of n-butyl acrylate, 31. The monomer emulsion for core part was obtained by mixing 2 parts by stirring.

Monomer emulsion for shell part: 50 parts of deionized water, 1.8 parts of Adeka Soap SR-1025, 0.04 part of ammonium persulfate, 2.3 parts of 2-hydroxyethyl acrylate, 3.7 parts of methacrylic acid, styrene 3 .7 parts, n-butyl acrylate 9.2 parts and methyl methacrylate 4 parts were mixed by stirring to obtain a monomer emulsion for shell part.

Production Example 2 of Polyester Resin PE
In a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser and water separator, 109 parts of trimethylolpropane, 141 parts of 1,6-hexanediol, 126 parts of 1,2-cyclohexanedicarboxylic acid anhydride and adipine After charging 120 parts of acid and raising the temperature from 160 ° C. to 230 ° C. over 3 hours, the resulting condensed water was distilled off with a water separator and subjected to a condensation reaction at 230 ° C. for 4 hours. Subsequently, in order to add a carboxyl group to the obtained condensation reaction product, 38.3 parts of trimellitic anhydride was further added, reacted at 170 ° C. for 30 minutes, and then cooled with 2- (dimethylamino) ethanol. 10 parts and ethylene glycol monobutyl ether were added to obtain a polyester resin PE solution having a solid content of 70%. Polyester resin PE had an acid value of 46 mgKOH / g, a hydroxyl value of 150 mgKOH / g, and a number average molecular weight of 1,400.

Production and production example 3 of block polyisocyanate curing agent XB
In a reaction vessel equipped with a thermometer, a thermostat, a stirring device, a reflux condenser, a nitrogen introduction tube, a dropping device and a simple trap for the removed solvent, Sumijour N-3300 (trade name, manufactured by Sumika Bayer Urethane Co., Ltd., 480 parts of isocyanurate structure-containing polyisocyanate derived from hexamethylene diisocyanate, solid content of about 100%, isocyanate group content of 21.8%), 150 parts of ethyl acetate and 310 parts of diethyl malonate, and stirring under a nitrogen stream Then, 4 parts of a 28% methanol solution of sodium methoxide was added and stirred at 65 ° C. for 8 hours. The amount of isocyanate in the obtained resin solution was 0.06 mol / Kg. To this was added 630 parts of n-butanol, the solvent was distilled off under reduced pressure for 3 hours while maintaining the temperature of the system at 90 to 95 ° C., and 90 parts of n-butanol was further added. About 1270 parts of about 60% blocked polyisocyanate curing agent XB solution were obtained. The simple trap contained 100 parts of ethanol.

Production and production example 4 of pigment dispersion
In a container equipped with a stirrer, 14.3 parts of polyester resin PE solution obtained in Production Example 2 (solid content 10 parts), 50 parts of JR-806 (trade name, manufactured by Teika, rutile titanium dioxide) and deionized water 30 parts were added, mixed uniformly, and 2- (dimethylamino) ethanol was added to the mixed solution to adjust to pH 8.0. Next, the obtained mixed solution was put in a wide-mouth glass bottle, sealed with glass beads having a diameter of about 1.3 mmφ as a dispersion medium, and dispersed for 4 hours with a paint shaker to obtain a pigment dispersion P-1. .

Production Example 5
In a container equipped with a stirrer, 14.3 parts of the polyester resin PE solution obtained in Production Example 2 (10 parts of solid content), 25 parts of Varifine BF-1 (trade name, manufactured by Sakai Chemical Industry Co., Ltd., barium sulfate powder) and 36 parts of deionized water was added and mixed uniformly, and 2- (dimethylamino) ethanol was added to the mixed solution to adjust to pH 8.0. Next, the obtained mixed solution was put in a wide-mouth glass bottle, sealed with glass beads having a diameter of about 1.3 mmφ as a dispersion medium, and dispersed for 4 hours with a paint shaker to obtain a pigment dispersion P-2. .

Production Example 6
In a container equipped with a stirrer, 14.3 parts of the polyester resin PE solution obtained in Production Example 2 (solid content 10 parts), 10 parts of carbon black MA-100 (trade name, manufactured by Mitsubishi Chemical Corporation, carbon black) and deionized 50 parts of water was added and mixed uniformly, and 2- (dimethylamino) ethanol was added to the mixed solution to adjust to pH 8.0. Next, the obtained mixed solution was put in a wide-mouth glass bottle, sealed with glass beads having a diameter of about 1.3 mmφ as a dispersion medium, and dispersed for 4 hours with a paint shaker to obtain a pigment dispersion P-3. .

Production Example 25 of Primer Paint X
100 parts of water-dispersible acrylic resin XA obtained in Production Example 1 (solid content 30 parts), 22 parts of polyester resin PE solution obtained in Production Example 2 (solid content 15 parts), obtained in Production Example 3 Block polyisocyanate curing agent XB solution 35 parts (solid content 21 parts), Cymel 325 (trade name, manufactured by Nippon Cytec Industries, Inc., melamine resin, solid content 80%) 16 parts (solid content 13 parts), obtained in Production Example 4 114 parts of pigment dispersion P-1, 60 parts of pigment dispersion P-2 obtained in Production Example 5, 7.5 parts of pigment dispersion P-3 obtained in Production Example 6, and the feeling obtained in Example 3 Two parts of warm polymer RC-3 were mixed uniformly. Subsequently, ACRYSOL ASE-60 (trade name, manufactured by Rohm and Haas, polyacrylic acid-based thickener), 2- (dimethylamino) ethanol, and deionized water were added to the mixture to adjust the pH to 8.0 and the solid content concentration. 45% primer paint X-1 was obtained.

Examples 26-29 and Comparative Examples 5-7
Primer paints X-2 to X-8 were obtained in the same manner as in Example 25 except that the temperature-sensitive polymer RC-3 was replaced as shown in Table 2 below.

The primer paint X-8 is a primer paint that does not contain a temperature-sensitive polymer.

Production and production example 7 of water-dispersible acrylic resin YA
A reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube and dropping device was charged with 130 parts of deionized water and 0.52 part of Aqualon KH-10, and stirred and mixed in a nitrogen stream. The temperature was raised to 80 ° C. Next, 1% of the total amount of the following monomer emulsion (1) and 5.3 parts of a 6% aqueous solution of ammonium persulfate were charged in the reaction vessel and maintained at 80 ° C. for 15 minutes. Then, the remaining monomer emulsion (1) was dripped in the reaction container hold | maintained at the same temperature over 3 hours, and it age | cure | ripened for 1 hour after completion | finish of dripping.

  Thereafter, the following monomer emulsion (2) was added dropwise over 1 hour, and after aging for 1 hour, the mixture was cooled to 30 ° C. while gradually adding 40 parts of a 5% 2- (dimethylamino) ethanol aqueous solution to the reaction vessel, The sample was discharged while being filtered through a 100 mesh nylon cloth, average particle size 100 nm (submicron particle size distribution measuring device COULTER N4 type (trade name, manufactured by Beckman Coulter, Inc.), diluted with deionized water and measured at 20 ° C. An aqueous dispersion of water-dispersible acrylic resin YA having a solid content concentration of 30% was obtained. The water dispersible acrylic resin YA had an acid value of 33 mgKOH / g and a hydroxyl value of 25 mgKOH / g.

  Monomer emulsion (1): 42 parts deionized water, 0.72 parts Aqualon KH-10, 2.1 parts methylenebisacrylamide, 2.8 parts styrene, 16.1 parts methyl methacrylate, 28 parts ethyl acrylate and n- Monomer emulsion (1) was obtained by mixing 21 parts of butyl acrylate by stirring.

Monomer emulsion (2): 18 parts deionized water, 0.31 part Aqualon KH-10, 0.03 part ammonium persulfate, 5.1 parts methacrylic acid, 5.1 parts 2-hydroxyethyl acrylate, 3 parts styrene, Monomer emulsion (2) was obtained by mixing 6 parts of methyl methacrylate, 1.8 parts of ethyl acrylate and 9 parts of n-butyl acrylate by stirring.

Production and production example 8 of glitter pigment dispersion AL
In a container equipped with a stirrer, 19 parts of aluminum pigment paste GX-180A (trade name, manufactured by Asahi Kasei Metals Co., Ltd., metal content 74%), 35 parts of 2-ethyl-1-hexanol, phosphate group-containing resin solution (Note 1) ) 8 parts (solid content 4 parts) and 2- (dimethylamino) ethanol 0.2 part were charged and mixed uniformly to obtain a bright pigment dispersion AL.
(Note 1) Phosphate group-containing resin solution: It consists of 27.5 parts of methoxypropanol and 27.5 parts of isobutanol in a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube and dropping device. A mixed solvent is added and heated to 110 ° C., 25 parts of styrene, 27.5 parts of n-butyl methacrylate, 20 parts of isostearyl acrylate (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., branched higher alkyl acrylate), 4-hydroxybutyl 7.5 parts of acrylate, 15 parts of phosphoric acid group-containing polymerizable unsaturated monomer (Note 2), 12.5 parts of 2-methacryloyloxyethyl acid phosphate, 10 parts of isobutanol, and 4 parts of tert-butyl peroxyoctanoate The reaction vessel was charged with 121.5 parts of the mixture over 4 hours, and further tert-butyl Mixture consisting of 0.5 parts peroxyoctanoate and 20 parts of isopropanol over a period of 1 hour was added dropwise to the reaction vessel.

Thereafter, the contents of the reaction vessel were aged by stirring for 1 hour to obtain a phosphate group-containing resin solution having a solid concentration of 50%. The phosphoric acid group-containing resin had an acid value of 83 mgKOH / g, a hydroxyl value of 29 mgKOH / g, and a weight average molecular weight of 10,000.
(Note 2) Phosphoric acid group-containing polymerizable unsaturated monomer: 57.5 parts monobutyl phosphoric acid and 41 parts isobutanol in a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube and dropping device The mixture was heated to 90 ° C., 42.5 parts of glycidyl methacrylate was added dropwise over 2 hours, and the mixture was further aged with stirring for 1 hour. Thereafter, 59 parts of isopropanol was added to the reaction vessel to obtain a phosphate group-containing polymerizable unsaturated monomer solution having a solid concentration of 50%. The acid value due to the phosphate group of the obtained monomer was 285 mgKOH / g.

Production Example 30 of Base Paint Y
In aqueous dispersion 100 parts (solid content 30 parts) of water-dispersible acrylic resin YA obtained in Production Example 7, 57 parts (solid content 40 parts) of hydroxyl group-containing polyester resin PE solution obtained in Production Example 2, The obtained luster pigment dispersion AL 62.2 parts (solid content 18 parts), Cymel 325 (trade name, manufactured by Nippon Cytec Industries, Inc., melamine resin, solid content 80%) 37.5 parts (solid content 30 parts), and 2 parts of the thermosensitive polymer RC-1 obtained in Example 1 were mixed uniformly. Subsequently, ACRYSOL ASE-60, 2- (dimethylamino) ethanol and deionized water were added to the mixture to obtain a base paint Y-1 having a pH of 8.0 and a solid content concentration of 25%.

Examples 31-53 and Comparative Examples 8-10
Base paints Y-2 to Y-27 were obtained in the same manner as in Example 30, except that the temperature-sensitive polymer RC-1 was replaced as shown in Table 3 below.

The base paint Y-27 is a base paint that does not contain a temperature-sensitive polymer.

Preparation of test plates Base paints (Y) obtained in Examples 25 to 29 and Comparative Examples 5 to 7 and primer paints (X-1) to (X-8), Examples 30 to 53 and Comparative Examples 8 to 10 Using -1) to (Y-27), test plates were prepared and evaluated as follows.

Preparation of test article "Electron GT-10" (trade name, manufactured by Kansai Paint Co., Ltd., cationic electrodeposition paint) on a cold-rolled steel sheet treated with zinc phosphate of length 300mm x width 450mm x thickness 0.8mm Was coated by electrodeposition so as to have a cured film thickness of 20 μm, and cured by heating at 170 ° C. for 30 minutes to produce a test article.

Example 54
On the test object, the primer paint X-8 obtained in Comparative Example 7 was electrostatically coated with a rotary atomizing electrostatic coater so as to have a cured film thickness of 20 μm. An uncured primer coating was formed on the coating. After standing for 3 minutes and preheating at 80 ° C. for 3 minutes, the substrate having the uncured primer coating film was rotated and atomized with the base paint Y-1 obtained in Example 30. Using a coating machine, electrostatic coating was performed so that the cured film thickness was 15 μm, and an uncured base coating film was formed thereon. After standing for 3 minutes and preheating at 80 ° C. for 3 minutes, the coated article having the uncured primer coating and the uncured base coating was treated with Magiclon KINO-1210 (trade name, manufactured by Kansai Paint Co., Ltd., Acid / epoxy curable acrylic resin-based organic solvent-type clear coating) was electrostatically applied to a cured film thickness of 35 μm, and an uncured clear coating film was formed thereon. After being allowed to stand for 7 minutes, the object to be coated is heated at 140 ° C. for 30 minutes, and the primer coating, the base coating and the clear coating are baked at the same time, and the multilayer coating film forming method of the method I (3C1B) is performed. The test plate Z-1 used was produced.

Examples 55-83 and Comparative Examples 11-15
Test plates Z-2 to Z-35 were obtained in the same manner as in Example 54 except that the paint shown in Table 4 below was used. Moreover, the test of smoothness, sharpness, and FF property (flip-flop property) was done by the method mentioned later. The evaluation results are also shown in the table.

Example 84
An intermediate coating (trade name “TP-65”, manufactured by Kansai Paint Co., Ltd., polyester resin / amino resin-based organic solvent-based coating composition) is applied on the test object to a cured film thickness of 25 μm. After standing for 5 minutes, preheating was performed at 80 ° C. for 5 minutes, and further heating at 140 ° C. for 30 minutes to obtain a cured coating film. Subsequently, the base coating Y-1 obtained in Example 30 was electrostatically coated with a rotary atomization type electrostatic coating machine so as to have a cured film thickness of 15 μm, and an uncured base coating film was formed thereon. Formed. After standing for 3 minutes and preheating at 80 ° C. for 3 minutes, the coated material having the uncured base coating was treated with Magiclon KINO-1210 (trade name, manufactured by Kansai Paint Co., Ltd., acid / epoxy curable acrylic resin). System-based organic solvent-type top coat clear coating) was electrostatically coated so that the cured film thickness was 35 μm, and an uncured clear coating film was formed thereon. After leaving for 7 minutes, the object to be coated is heated at 140 ° C. for 30 minutes, and the base coating film and the clear coating film are baked at the same time, and a test plate using the multilayer coating film forming method of Method II (2C1B) Z-36 was produced.

Examples 85-107 and Comparative Examples 16-18
Test plates Z-37 to 62 were obtained in the same manner as in Example 84 except that the paint shown in Table 5 below was used. Moreover, the evaluation test of smoothness, sharpness, and FF property (flip-flop property) was done by the method mentioned later. The evaluation results are also shown in the table.

Evaluation test <Smoothness>
The test plate was evaluated by the value of Wc measured by “Wave Scan DOI” (trade name, manufactured by BYK Gardner). In addition, Wc means that the smoothness of a coating surface is so high that a value is small. As evaluation, S-B is a pass and C is a failure.
The value of S: Wc is less than 7, and the smoothness is extremely excellent.
A: The value of Wc is 7 or more and less than 8.5, and smoothness is excellent.
B: The value of Wc is 8.5 or more and less than 10, and the smoothness is slightly inferior.
C: The value of Wc is 10 or more, and the smoothness is inferior.

<Vividness>
The test plate was evaluated by the value of Wa measured by “Wave Scan DOI” (trade name, manufactured by BYK Gardner). Note that Wa means that the smaller the value, the higher the sharpness of the paint surface. As evaluation, S-B is a pass and C is a failure.
S: The value of Wa is less than 8, and the sharpness is extremely excellent.
A: The value of Wa is 8 or more and less than 10, and the sharpness is excellent.
B: The value of Wa is 10 or more and less than 12, and the sharpness is slightly inferior.
C: The value of Wa is 12 or more, and the sharpness is inferior.

<FF property (flip-flop property)>
The test plate was evaluated by an FF value derived from an L value (brightness) measured by a “multi-angle spectrocolorimeter MA-68” (trade name, manufactured by X-Rite). In addition, FF value was calculated | required by the following formula.
FF value = L value with a light receiving angle of 15 degrees / L value with a light receiving angle of 110 degrees The greater the FF value, the greater the change in the L value (brightness) depending on the observation angle (light receiving angle), and the better the flip-flop property. Show. As evaluation, S-B is a pass and C is a failure.
S: The FF value is 5.5 or more, and the flip-flop property is extremely excellent.
A: The FF value is 4.8 or more and less than 5.5, and the flip-flop property is excellent.
B: The FF value is 4 or more and less than 4.8, and the flip-flop property is slightly inferior.
C: The FF value is less than 4, and the flip-flop property is inferior.

Claims (12)

  A temperature-sensitive polymer that exhibits a temperature responsiveness having a lower critical eutectic temperature and exists in a particle state in water and / or an organic solvent, and is a polymerizable unsaturated component constituting the polymer A temperature-sensitive polymer, wherein the monomer contains an N-substituted (meth) acrylamide derivative and / or vinyl methyl ether.   As the polymerizable unsaturated monomer constituting the polymer, 10 to 100% by mass of the polymerizable unsaturated monomer (A) in which the homopolymer exhibits the lower critical solution temperature, and the homopolymer does not exhibit the lower critical solution temperature. 2. The thermosensitive polymer according to claim 1, comprising 0 to 90% by mass of the unsaturated monomer (B).   The polymerizable unsaturated monomer (B) in which the homopolymer does not exhibit a lower critical eutectic temperature is at least one polymerization selected from (meth) acrylamide, dimethyl (meth) acrylamide, hydroxyethyl (meth) acrylamide, and acryloylmorpholine. The temperature-sensitive polymer according to claim 2, comprising a polymerizable unsaturated monomer.   Polymerization in which the polymerizable unsaturated monomer (B) in which the homopolymer does not exhibit the lower critical eutectic temperature contains the monomer (B-1) having two or more polymerizable unsaturated groups and constitutes a thermosensitive polymer. The temperature-sensitive polymer according to claim 2 or 3, wherein the monomer (B-1) is contained in an amount of 0.01 to 5% by mass based on the total amount of the polymerizable unsaturated monomer.   2. In water, the average particle diameter D1 is 300 nm or more at a temperature of 20 ° C., the average particle diameter D2 is 200 nm or less at a temperature of 80 ° C., and D1 / D2 is 3 or more. 5. The temperature-sensitive polymer according to any one of 4 above.   When 15% by mass of the thermosensitive polymer is contained in water, the viscosity V1 at a temperature of 20 ° C. is 500 mPa · s or more, the viscosity V2 at a temperature of 80 ° C. is 200 mPa · s or less, and V1 / V2 The temperature-sensitive polymer according to any one of claims 1 to 5, wherein is 5 or more.   A coating composition comprising 0.5 to 10% by mass of the thermosensitive polymer according to any one of claims 1 to 6, based on the resin solids mass.   A coated article obtained by coating the coating composition according to claim 7 on an object to be coated.   A primer coating composition according to claim 7, wherein a primer coating composition, a base coating composition, and a clear coating composition are sequentially coated on an object to be coated, and the resulting three-layer coating film is heated and cured simultaneously. A method for forming a multilayer coating film, which is a coating composition.   In the method for forming a multi-layer coating film in which a primer coating, a base coating, and a clear coating are sequentially applied on an object to be coated, and the three layers are heated and cured simultaneously, the base coating is the coating composition according to claim 7. A method for forming a multilayer coating film.   8. A multi-layer coating film forming method in which a base coating and a clear coating are sequentially applied on an object to be coated, and two layers are heated and cured simultaneously, wherein the base coating is the coating composition according to claim 7. A method for forming a multilayer coating film.   The coated article obtained by the multilayer coating-film formation method of any one of Claims 9-11.