Crosslinked polyurethane microparticles, method for producing crosslinked polyurethane microparticles, and paint

Abstract

To provide crosslinked polyurethane particles which are resistant to aggregation, have good dispersibility, and have excellent flexibility, and the flexibility is not easily lost even under low-temperature conditions, and which are a reaction product of raw materials containing polyester polyol and have excellent hydrolysis resistance. [Solution] The crosslinked polyurethane particles are a reaction product obtained by reacting raw materials containing a polyester polyol having structural units derived from a dicarboxylic acid having 8 or more carbon atoms and structural units derived from an aliphatic diol A, and an isocyanate compound, while the raw materials are dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer, wherein the aliphatic polyol A is a branched polyol having a branched structure or a linear polyol having 5 or less carbon atoms, and the polyester polyol has a hydroxyl value of 60 to 200 mgKOH / g.

Description

[Technical Field]

[0001] The present invention relates to crosslinked polyurethane microparticles, a method for producing crosslinked polyurethane microparticles, and a coating material. [Background technology]

[0002] Traditionally, polyvinyl chloride resins have been widely used as materials for automotive interiors, etc., due to their flexibility, flame retardancy, designability, and vacuum formability, as well as their cost-effectiveness. However, in recent years, the use of thermoplastic polyolefins has increased in response to demands for weight reduction and the resolution of dioxin issues caused by halogenated compounds. Thermoplastic polyolefins are promising alternatives to polyvinyl chloride resins because they possess various physical properties, such as weather resistance and chemical resistance, are flexible even without the use of plasticizers, and are low-density and lightweight. However, molded products, such as components made of thermoplastic polyolefins, are insufficient in terms of abrasion resistance, flexibility, oil resistance, adhesion, and weather resistance, and are not considered to have a pleasant feel that creates a luxurious impression.

[0003] In contrast, polyurethane-based resins such as polyurethane resins, polyurea resins, and polyurethane-polyurea resins are resin materials that are excellent in various physical properties such as abrasion resistance, flexibility, and adhesion, and are also suitable for various processing methods. For this reason, polyurethane-based resins are widely used as binders incorporated into various coating agents, inks, paints, etc., and as materials for forming films, sheets, and various molded products.

[0004] For example, three-dimensionally crosslinked polyurethane gel particles have been proposed for use in cosmetics, paints, etc. (Patent Documents 1 to 3). Also, polyurethane resin beads for paints, obtained by reacting a biomass-derived polyol component with an isocyanate component, have been proposed (Patent Document 4). Furthermore, a method for producing polyurethane beads for use in paints, etc., has been proposed, which includes a step of reacting a polyester polyol, which is a reaction product of 3-methyl-1,5-pentanediol and adipic acid, with an isocyanate component in water (Patent Document 5). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-189552 [Patent Document 2] Patent No. 5826814 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-24319 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-18714 [Patent Document 5] Japanese Patent Application Laid-Open No. 2013-67793 Summary of the Invention [Problem to be solved by the invention]

[0006] However, conventional resin particles such as polyurethane beads proposed in Patent Documents 1 to 5, etc., tend to aggregate (adhere) in various liquid media such as organic solvents as their flexibility increases, and therefore dispersibility is not necessarily good. Furthermore, flexibility and hydrolysis resistance are not necessarily good, and flexibility is easily lost under low temperature conditions, leaving room for improvement.

[0007] The present invention has been made in view of the problems associated with the prior art, and an object of the present invention is to provide crosslinked polyurethane microparticles that are resistant to aggregation, have good dispersibility, have excellent flexibility, and are resistant to loss of flexibility even under low-temperature conditions, and that are excellent in hydrolysis resistance despite being a reaction product of raw materials containing polyester polyol, and a method for producing the same.

[0008] Another object of the present invention is to provide a coating material that is smooth to the touch, has good gripping properties, and is excellent in flexibility and bendability, and is capable of forming a coating film such as a surface treatment film whose flexibility and bendability are not easily impaired even under low-temperature conditions. [Means for solving the problem]

[0009] That is, according to the present invention, the following crosslinked polyurethane fine particles are provided. [1] Crosslinked polyurethane particles that are a reaction product obtained by reacting raw materials containing a polyester polyol having structural units derived from a dicarboxylic acid having 8 or more carbon atoms and structural units derived from an aliphatic polyol A, and an isocyanate compound, while the raw materials are dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer, wherein the aliphatic polyol A is a branched polyol having a branched structure or a linear polyol having 5 or less carbon atoms, and the hydroxyl value of the polyester polyol is 60 to 200 mgKOH / g. [2] The crosslinked polyurethane particles according to [1], wherein the dicarboxylic acid and the aliphatic polyol A are both biomass-derived compounds, and the biomass ratio is 50% by mass or more. [3] The crosslinked polyurethane particles according to [1] or [2], wherein at least one of the polyester polyol and the isocyanate compound is a tri- or higher functional compound. [4] The crosslinked polyurethane particles according to [1] or [2], wherein the isocyanate compound is at least one of an aliphatic diisocyanate and a derivative thereof. [5] The crosslinked polyurethane particles according to [1] or [2], wherein the isocyanate compound is 1,5-pentamethylene diisocyanate or an isocyanurate of 1,5-pentamethylene diisocyanate. [6] The crosslinked polyurethane particles according to any one of [1] to [5], wherein the dicarboxylic acid has 12 or less carbon atoms. [7] The crosslinked polyurethane microparticles according to any one of [1] to [6], wherein the liquid medium is an organic solvent, and the dispersion stabilizer is a polyurea colloidal particle composed of a solvated portion solvated in the organic solvent and a non-solvated portion not solvated in the organic solvent. [8] The crosslinked polyurethane microparticles according to any one of [1] to [6], wherein the liquid medium is an aqueous liquid medium containing water, and the dispersion stabilizer is a surfactant. [9] The crosslinked polyurethane microparticles according to any one of [1] to [8], wherein the raw materials further contain an aliphatic polyol B, and the amount of the aliphatic polyol B in the total of the polyester polyol, the isocyanate compound, and the aliphatic polyol B is 0.1 to 10 mass%.

[10] The crosslinked polyurethane particles according to any one of [1] to [9], which have a volume average particle size of 0.1 to 500 μm.

[11] Crosslinked polyurethane particles according to any one of [1] to

[10] above, which have a glass transition temperature of −30° C. or lower and a 10% compressive strength of 1.0 MPa or lower.

[0010] The present invention also provides the following method for producing crosslinked polyurethane microparticles.

[12] A method for producing crosslinked polyurethane microparticles, comprising a step of reacting raw materials containing a polyester polyol having structural units derived from a dicarboxylic acid having 8 or more carbon atoms and structural units derived from an aliphatic polyol A, and an isocyanate compound, in a state where the raw materials are dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer, to form crosslinked polyurethane microparticles as a reaction product, wherein the aliphatic polyol A is a branched polyol having a branched structure or a linear polyol having 5 or less carbon atoms, and the hydroxyl value of the polyester polyol is 60 to 200 mgKOH / g.

[0011] Furthermore, according to the present invention, there is provided the following paint.

[13] A coating material containing the crosslinked polyurethane fine particles according to any one of [1] to

[11] .

[14] The coating material according to

[13] , further comprising a synthetic resin, wherein the content of the crosslinked polyurethane microparticles is 10 to 100 parts by mass per 100 parts by mass of the synthetic resin. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide crosslinked polyurethane microparticles that are resistant to aggregation, have good dispersibility, have excellent flexibility, and are resistant to loss of flexibility even under low-temperature conditions, and that are excellent in hydrolysis resistance despite being a reaction product of raw materials containing polyester polyol, as well as a method for producing the same.

[0013] Furthermore, according to the present invention, it is possible to provide a coating material that is smooth to the touch, has good gripping properties, and is excellent in flexibility and bendability, and is capable of forming a coating film such as a surface treatment film whose flexibility and bendability are not easily impaired even under low temperature conditions. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Crosslinked polyurethane particles> Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. One embodiment of the crosslinked polyurethane microparticles of the present invention is a reaction product obtained by reacting raw materials containing a polyester polyol and an isocyanate compound in a state where the raw materials are dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer. The polyester polyol has structural units derived from a dicarboxylic acid having 8 or more carbon atoms and structural units derived from an aliphatic polyol A. The aliphatic polyol A is a branched polyol having a branched structure or a linear polyol having 5 or less carbon atoms, and the hydroxyl value of the polyester polyol is 60 to 200 mgKOH / g. Hereinafter, the crosslinked polyurethane microparticles of this embodiment will be described in detail.

[0015] (polyester polyol) The polyester polyol is a resin having a structural unit (i) derived from a dicarboxylic acid having 8 or more carbon atoms and a structural unit (ii) derived from an aliphatic polyol A. The polyester polyol is preferably composed essentially of the structural unit (i) and the structural unit (ii) alone.

[0016] The dicarboxylic acid has 8 or more carbon atoms. However, if the dicarboxylic acid has too many carbon atoms, it tends to have low polarity and be easily soluble in a liquid medium. For this reason, the dicarboxylic acid preferably has 12 or less carbon atoms. Typical polyester polyols are more susceptible to hydrolysis than other polymer polyols such as polyether polyols and polycarbonate polyols. In contrast, by using a polyester polyol containing a dicarboxylic acid having 8 or more carbon atoms, crosslinked polyurethane microparticles with improved hydrolysis resistance can be obtained. Note that if the number of carbon atoms constituting the dicarboxylic acid molecule is less than 8, the glass transition temperature of the crosslinked polyurethane microparticles may increase, and the flexibility and hydrolysis resistance may decrease.

[0017] Examples of dicarboxylic acids having 8 or more carbon atoms include suberic acid, sebacic acid, azelaic acid, and dodecanedioic acid. Of these, sebacic acid is preferred.

[0018] Use of an aliphatic polyol A lowers the glass transition temperature of the crosslinked polyurethane and results in crosslinked polyurethane microparticles with superior flexibility compared to the use of polyols other than aliphatic polyol A, such as aromatic polyols. Examples of aliphatic polyol A include branched polyols having a branched structure, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol (MPD), and neopentyl glycol, as well as linear polyols having 5 or fewer carbon atoms; low-molecular-weight alkylene oxide adducts (number-average molecular weight less than 500) of these; and polyhydric alcohols such as glycerin and trimethylolpropane. Among these, 1,3-propanediol is preferred. Use of a linear polyol having 6 or more carbon atoms as aliphatic polyol A increases the crystallinity of the crosslinked polyurethane, resulting in reduced dispersibility of the crosslinked polyurethane microparticles and reduced flexibility at low temperatures.

[0019] Both the dicarboxylic acid and the aliphatic polyol A are preferably biomass-derived compounds. By using the biomass-derived dicarboxylic acid and the aliphatic polyol A, crosslinked polyurethane microparticles with reduced environmental impact can be obtained. Specifically, the biomass ratio of the crosslinked polyurethane microparticles is preferably 50% by mass or more, and more preferably 70% by mass or more.

[0020] The hydroxyl value of the polyester polyol is 60 to 200 mgKOH / g, preferably 70 to 150 mgKOH / g, and more preferably 80 to 140 mgKOH / g in consideration of realizing a coating film that can exhibit flexibility at low temperatures. If the hydroxyl value of the polyester polyol is less than 60 mgKOH / g, the flexibility of the crosslinked polyurethane microparticles will increase but the dispersibility will decrease. On the other hand, if the hydroxyl value of the polyester polyol is more than 200 mgKOH / g, the glass transition temperature (Tg) of the crosslinked polyurethane microparticles will tend to increase and the flexibility will decrease.

[0021] (Isocyanate compounds) As the isocyanate compound, any of the polyisocyanates (diisocyanates) used in the production of conventional polyurethanes can be used. Examples of the isocyanate compound include aromatic diisocyanates such as toluene-2,4-diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate diphenyl ether, 4,4'-methylenebis(phenylene isocyanate) (MDI), durylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate (XDI), 1,5-naphthalene diisocyanate, benzidine diisocyanate, o-nitrobenzidine diisocyanate, and 4,4'-diisocyanate dibenzyl. cyanates; aliphatic diisocyanates such as methylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, and 1,10-decamethylene diisocyanate; alicyclic diisocyanates such as 1,4-cyclohexylene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,5-tetrahydronaphthalene diisocyanate, isophorone diisocyanate, hydrogenated MDI, and hydrogenated XDI; polyurethane prepolymers obtained by reacting these isocyanate compounds with low-molecular-weight polyols or polyamines so that the terminals are isocyanate groups; and the like.

[0022] Furthermore, the isocyanate compound may be a trifunctional or higher polyfunctional isocyanate compound, which is a derivative of the above-mentioned isocyanate compound. Examples of the trifunctional or higher polyfunctional isocyanate compound include the isocyanurate, biuret, adduct, and polymeric forms of the above-mentioned isocyanate compounds. Other examples that may be used include a dimer of 2,4-toluylene diisocyanate, triphenylmethane triisocyanate, tris-(p-isocyanatophenyl)thiophosphite, polyfunctional aromatic isocyanates, polyfunctional aromatic aliphatic isocyanates, polyfunctional aliphatic isocyanates, fatty acid-modified polyfunctional aliphatic isocyanates, blocked polyisocyanates such as blocked polyfunctional aliphatic isocyanates, and polyisocyanate prepolymers.

[0023] The isocyanate compound is preferably at least one of an aliphatic diisocyanate and its derivatives. By using an aliphatic diisocyanate or a derivative thereof, yellowing (deterioration of the color of the coating film) can be more effectively prevented when used in, for example, a coating material compared to when an aromatic diisocyanate or the like is used.

[0024] The isocyanate compound is preferably any one of 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, an isocyanurate of 1,5-pentamethylene diisocyanate, and an isocyanurate of 1,6-hexamethylene diisocyanate. The isocyanate compound is more preferably an isocyanurate of 1,5-pentamethylene diisocyanate, because it can further reduce the 10% compressive strength of the crosslinked polyurethane microparticles and facilitate the formation of a coating film, such as a surface treatment film, whose flexibility and bendability are less likely to be impaired even under low-temperature conditions.

[0025] At least one of the polyester polyol and the isocyanate compound is preferably a trifunctional or higher functional compound. For example, when the isocyanate compound is a bifunctional compound, the polyester polyol is preferably a trifunctional or higher functional compound. Furthermore, when the polyester polyol is a bifunctional compound, the isocyanate compound is preferably a trifunctional or higher functional compound. When at least one of the polyester polyol and the isocyanate compound is a trifunctional or higher functional compound, three-dimensionally crosslinked crosslinked polyurethane microparticles can be more easily obtained. The number of functional groups of the polyester polyol and the isocyanate compound may be varied depending on the intended use of the crosslinked polyurethane microparticles. Furthermore, the ratio of the amount of the polyester polyol and the isocyanate compound to be reacted is preferably in the range of NCO group / OH group (molar ratio) = 0.5 to 1.2.

[0026] (Aliphatic polyol B) The raw materials preferably further contain an aliphatic polyol B. That is, the crosslinked polyurethane microparticles are preferably a reaction product obtained by reacting raw materials containing a polyester polyol, an isocyanate compound, and an aliphatic polyol B under predetermined conditions. For example, when the polyester polyol and the isocyanate compound are both bifunctional compounds, the aliphatic polyol B can be a trifunctional or higher functional compound.

[0027] As the aliphatic polyol B, a short-chain polyol used in the production of conventional polyurethanes can be used. Examples of the aliphatic polyol B include the same as those described above for the aliphatic polyol A. Examples of the aliphatic polyol B include aliphatic glycols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol; low-mole alkylene oxide adducts (number-average molecular weight less than 500) of these aliphatic glycols; and polyhydric alcohols such as glycerin and trimethylolpropane. It is preferable to use a biomass-derived compound as the aliphatic polyol B. The aliphatic polyol A and the aliphatic polyol B may be the same or different.

[0028] In the raw materials, the amount of aliphatic polyol B relative to the total of polyester polyol, isocyanate compound, and aliphatic polyol B is preferably 0.1 to 10 mass%, more preferably 0.1 to 5 mass%. By setting the amount of aliphatic polyol B within the above range, the glass transition temperature can be lowered.

[0029] (Crosslinked polyurethane particles) The crosslinked polyurethane microparticles of this embodiment are a reaction product obtained by reacting raw materials containing the aforementioned polyester polyol and isocyanate compound in a state where the raw materials are dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer. The dispersion stabilizer is a component that functions as a so-called emulsifier to stably disperse the raw materials in the form of fine particles in the liquid medium. Note that if the raw materials are reacted in the absence of a dispersion stabilizer, rather than in a state where the raw materials are dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer, it is virtually impossible to obtain the desired crosslinked polyurethane microparticles. Furthermore, if the raw materials are reacted in the presence of a dispersion stabilizer, it is expected that the surfaces of the resulting particles will be coated with the dispersion stabilizer, or that the dispersion stabilizer will become finer particles and adhere to the surfaces of the particles, but it is difficult or virtually impossible to identify the state of the dispersion stabilizer by analysis, etc.

[0030] The volume average particle diameter of the crosslinked polyurethane microparticles is preferably 0.1 to 500 μm, more preferably 1 to 100 μm. The glass transition temperature of the crosslinked polyurethane microparticles is preferably −30° C. or lower, more preferably −40 to −60° C. Generally, the lower the glass transition temperature, the more flexible the resin microparticles are, but the more likely they are to aggregate. The crosslinked polyurethane microparticles of this embodiment have a suitable glass transition temperature in the above range, and therefore have a good balance between flexibility and dispersibility.

[0031] The 10% compressive strength of the crosslinked polyurethane microparticles is preferably 1.0 MPa or less, and more preferably 0.05 to 0.2 MPa. Since the 10% compressive strength is preferably in the above range, the crosslinked polyurethane microparticles of this embodiment have excellent flexibility.

[0032] <Method of manufacturing crosslinked polyurethane particles> The crosslinked polyurethane microparticles of this embodiment can be produced according to the method described below. That is, one embodiment of the method for producing crosslinked polyurethane microparticles of the present invention includes a step (reaction step) of reacting raw materials containing the above-mentioned polyester polyol and isocyanate compound in a state where the raw materials are dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer to form crosslinked polyurethane microparticles as a reaction product. The method for producing crosslinked polyurethane microparticles of this embodiment will be described in detail below.

[0033] (Reaction step) In the reaction step, raw materials containing a polyester polyol and an isocyanate compound are reacted in a state of being dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer, thereby forming crosslinked polyurethane fine particles as a reaction product.

[0034] [Liquid medium] The liquid medium is a medium for reacting raw materials in a state where the raw materials are dispersed in the form of fine particles. As the liquid medium, water, a water-soluble organic solvent, or a water-insoluble organic solvent can be used.

[0035] [Dispersion stabilizer] The dispersion stabilizer is a component that functions as a so-called emulsifier to stably disperse raw materials in the liquid medium in the form of fine particles. It is preferable to select and use the dispersion stabilizer appropriately depending on the type of liquid medium. When an aqueous liquid medium containing water and a water-soluble organic solvent is used as the liquid medium, more specifically when water is used as the liquid medium, it is preferable to use a surfactant as the dispersion stabilizer. Examples of surfactants that can be used include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Of these, it is preferable to use nonionic surfactants. Examples of nonionic surfactants include cellulose derivatives such as hydroxypropyl methylcellulose, as well as alkyl ether, phenyl ether, ether ester, ester, and amide nonionic surfactants.

[0036] Furthermore, when an organic solvent is used as the liquid medium, more specifically when a water-insoluble organic solvent is used as the liquid medium, it is preferable to use polyurea colloid particles composed of a solvated portion solvated in the organic solvent and a non-solvated portion not solvated in the organic solvent as the dispersion stabilizer.

[0037] In addition, reacting raw materials dispersed in the form of fine particles in an organic solvent containing polyurea colloidal particles as a dispersion stabilizer is preferable because it is possible to obtain crosslinked polyurethane fine particles with improved hydrolysis resistance compared to reacting raw materials dispersed in the form of fine particles in water containing a surfactant as a dispersion stabilizer.

[0038] It is preferable to use an organic solvent that does not have an active hydrogen group. Examples of such organic solvents include hydrocarbon solvents such as pentane, hexane, heptane, octane, decane, petroleum ether, petroleum benzine, ligroin, petroleum spirit, cyclohexane, methylcyclohexane, toluene, xylene, ethylcyclohexane, and dimethylcyclohexane, as well as dimethylpolysiloxane. Among them, it is preferable to use an organic solvent whose boiling point is 150° C. or less, from the viewpoint of simplifying the process of separating the generated crosslinked polyurethane microparticles.

[0039] The particle size of the non-solvated portion constituting the polyurea colloidal particles is preferably 0.01 to 1.0 μm. The polyurea colloidal particles can be formed by reacting an oil-modified polyol, a polyisocyanate (or an NCO-terminated prepolymer composed of these compounds), and a polyamine in an organic solvent.

[0040] As the reaction proceeds, insoluble urea domains are formed in the organic solvent due to hydrogen bonding between urea bonds. At the same time, the molecular chains of the oil-modified polyol are solvated in the organic solvent, and the insoluble urea domains are aggregated, forming stable polyurea colloidal particles that are prevented from becoming large.

[0041] An oil-modified polyol and a polyisocyanate are reacted in an organic solvent or without solvent to synthesize a prepolymer having NCO groups. An organic solvent is then added to dilute the mixture, preparing a solution with a concentration of 5 to 70% by mass. A polyamine solution with a concentration of 1 to 20% by mass is then gradually added to the solution while stirring to initiate a polyurea reaction, yielding a polyurea colloid solution containing polyurea colloid particles.

[0042] The number-average molecular weight of the oil-modified polyol is preferably 700 to 3,000. Examples of the oil-modified polyol include those obtained by alcoholysing various types of oils and fats with lower alcohols or glycols, partially saponifying oils and fats, and esterifying hydroxyl-containing fatty acids with glycols. Examples of the hydroxyl-containing fatty acids include ricinoleic acid, 12-hydroxystearic acid, castor oil fatty acids, and hydrogenated castor oil fatty acids.

[0043] The reaction of the oil-modified polyol with the polyisocyanate is preferably carried out under the condition of 1<(NCO group / OH group)≦2 (molar ratio) to control the molecular weight of the solvated prepolymer. The number average molecular weight of the obtained prepolymer is preferably 500 to 15,000. Examples of polyisocyanates include aliphatic diisocyanates and alicyclic diisocyanates such as hexamethylene diisocyanate, hydrated TDI, hydrated MDI, isophorone diisocyanate, and hydrogenated XDI.

[0044] Examples of polyamines include short-chain diamines, aliphatic polyamines, alicyclic polyamines, aromatic polyamines, and hydrazines. Examples of short-chain diamines and aliphatic polyamines include methylenediamine, ethylenediamine, diaminopropane, diaminobutane, trimethylenediamine, trimethylhexamethylenediamine, hexamethylenediamine, octamethylenediamine, polyoxypropylenediamine, and polyoxypropylenetriamine. Examples of alicyclic polyamines include cyclopentanediamine, cyclohexyldiamine, 4,4-diaminodicyclohexylmethane, 1,4-diaminocyclohexane, bis-aminopropylpiperazine, thiourea, methyliminobispropylamine, norbornanediamine, and isophoronediamine. Examples of aromatic polyamines include phenylenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 4,4'-methylenebis(phenylamine), 4,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenyl sulfone. Examples of hydrazines include hydrazine, carbohydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, and phthalic acid dihydrazide.

[0045] The polyurea colloid particles function as a W / O type emulsifier or an O / O type emulsifier. The particle size of the crosslinked polyurethane microparticles produced can be controlled by adjusting the amount of polyurea colloid particles added relative to the polyisocyanate and polyester polyol. For example, the larger the amount of polyurea colloid particles added, the smaller the particle size of the crosslinked polyurethane microparticles produced. On the other hand, the smaller the amount of polyurea colloid particles added, the larger the particle size of the crosslinked polyurethane microparticles produced.

[0046] (Other processes) The above reaction process forms crosslinked polyurethane microparticles, yielding a dispersion containing the crosslinked polyurethane microparticles. The liquid medium is separated and removed from the dispersion under normal pressure or reduced pressure to obtain the desired crosslinked polyurethane microparticles. Examples of devices for separating and removing the liquid medium from the dispersion include a spray dryer, a vacuum dryer equipped with a filtration device, a vacuum dryer equipped with a stirrer, and a tray dryer. The drying temperature may be appropriately set taking into consideration the vapor pressure of the liquid medium, the softening temperature of the crosslinked polyurethane microparticles, and the particle size of the crosslinked polyurethane microparticles. Specifically, drying can be performed at 40 to 130°C under reduced pressure.

[0047] <Paint> A paint can be obtained by using the above-described crosslinked polyurethane microparticles. That is, one embodiment of the paint of the present invention contains the above-described crosslinked polyurethane microparticles. The paint of this embodiment can be obtained by dispersing or dissolving the crosslinked polyurethane microparticles, a synthetic resin, and various additives used as needed in a liquid medium such as water. The content of the synthetic resin in the paint is preferably 10 to 80 mass %, and more preferably 20 to 70 mass %, based on the solid content in the paint. The content of the crosslinked polyurethane microparticles in the paint is preferably 10 to 100 mass parts, and more preferably 10 to 50 mass parts, per 100 mass parts of the synthetic resin. The solid content in the paint is typically about 1 to 95 mass %.

[0048] Examples of synthetic resins include polyurethane resins, acrylic resins, silicone resins, and amide resins. Examples of additives include hindered phenol, phosphite, and thioether antioxidants; hindered amine light stabilizers; benzophenone and benzotriazole ultraviolet absorbers; hydrazine gas discoloration stabilizers; and metal deactivators.

[0049] Furthermore, in addition to design-imparting agents such as organic fine particles and inorganic fine particles, it is possible to appropriately use antifungal agents, flame retardants, etc. Examples of organic fine particles and inorganic fine particles include silica, silicone resin fine particles, fluororesin fine particles, acrylic resin fine particles, urethane resin fine particles, silicone-modified urethane resin fine particles, polyethylene fine particles, and reactive siloxane.

[0050] The coating material of this embodiment contains the above-mentioned crosslinked polyurethane microparticles, and therefore can form a coating film such as a surface treatment film that is smooth to the touch, has good grip, and is excellent in flexibility and flexibility, and whose flexibility and flexibility are not easily lost even under low-temperature conditions. Therefore, the crosslinked polyurethane microparticles of this embodiment and the coating material containing them are useful as materials for, for example, automotive interior materials such as instrument panels, covering materials for furniture, and covering materials for sundries that come into close contact with the skin, such as headphones. [Example]

[0051] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0052] <Preparation of polyurea colloid solution> (Preparation Example 1) 100 parts of a bifunctional oil-modified polyol (trade name "URIC Y-202", manufactured by Ito Oil Mills, hydroxyl value: 119.5 mgKOH / g) and 100 parts of n-octane were placed in a reaction vessel, and the oil-modified polyol was dissolved. The temperature was controlled at 50°C with stirring, and 47.3 parts of isophorone diisocyanate (NCO / OH (molar ratio) = 2) was gradually added over 1 hour. After reacting at 50°C for 3 hours, the mixture was heated to 80°C and reacted for an additional 3 hours. n-Octane was added to a concentration of 50%, yielding a solution (PP-1) containing a prepolymer with an NCO group content of 3.0%. The molecular weight of the prepolymer was 1,383. 40 parts of the resulting PP-1 and 60 parts of n-octane were placed in a reaction vessel. The temperature was controlled at 70°C while stirring, and 24.3 parts of an n-octane solution of isophoronediamine (isophoronediamine concentration: 10%) was gradually added over 5 hours and allowed to react. This resulted in a polyurea colloid solution (C-1) (solids content: 18.0%) with a ratio of (polyamine (urea bond) / prepolymer chain) x 100 = 12.15%. The resulting polyurea colloid solution (C-1) was a stable solution with a blue opalescent color.

[0053] <Preparing polyester polyol> Polyester polyols A to J shown in Table 1 were prepared. The meanings of the abbreviations in Table 1 are as follows. 1,3-PD; 1,3-propanediol MPD: 3-methyl-1,5-pentanediol TMP: Trimethylolpropane 1,6-HD: 1,6-hexanediol

[0054] TIFF0007734255000001.tif89170

[0055] <Preparing the isocyanate compound> The following isocyanate compounds A to D were prepared. Note that isocyanate compound C is a compound derived from petroleum resources, and isocyanate compounds A, B, and D are compounds derived from biomass. Isocyanate compound A: a modified trifunctional isocyanate compound represented by the following formula (B), trade name "STABIO D-376N", manufactured by Mitsui Chemicals, Inc., isocyanurate of pentamethylene diisocyanate, NCO%=23.6 Isocyanate compound B: a trifunctional isocyanate compound represented by the following formula (B), trade name "STABIO D-370N", manufactured by Mitsui Chemicals, Inc., isocyanurate of pentamethylene diisocyanate, NCO%=25.0 Isocyanate compound C: a trifunctional isocyanate compound represented by the following formula (A), trade name "Duranate TPA-100", manufactured by Asahi Kasei Corporation, isocyanurate of hexamethylene diisocyanate, NCO%=23.1 Isocyanate compound D: pentamethylene diisocyanate, trade name "Stabio PDI", manufactured by Mitsui Chemicals, Inc., NCO%=54.5

[0056] TIFF0007734255000002.tif47170

[0057] <Production of crosslinked polyurethane particles> Example 1 20 parts of polyester polyol A were heated to 60°C to dissolve, and then 0.2 parts of biomass-derived 1,3-propanediol and 7.8 parts of isocyanate compound A were added and mixed to obtain a mixture. 5 parts of the polyurea colloid solution (C-1) obtained in Preparation Example 1 and 25 parts of n-octane were placed in a stainless steel container and mixed. The mixture was gradually added to the container and reacted for 15 minutes using a homogenizer. This resulted in the formation of crosslinked polyurethane microparticles, yielding an emulsion containing crosslinked polyurethane microparticles. The resulting emulsion was stable without separation, and the average dispersed particle size of the dispersoid was 5 μm.

[0058] (Examples 2 to 7, Comparative Examples 1 to 6) Crosslinked polyurethane microparticles were formed in the same manner as in Example 1, except that the types and amounts of polyester polyols and the like shown in the upper rows of Tables 2-1 and 2-2 were used, and emulsions containing crosslinked polyurethane microparticles were obtained. All emulsions were stable without separation, and the average dispersed particle diameter of the dispersoid was 5 μm.

[0059] Example 8 20 parts of polyester polyol A were heated to 60°C and dissolved, followed by the addition and mixing of 0.5 parts of biomass-derived 1,3-propanediol and 7.3 parts of isocyanate compound A to obtain a mixture. 5 parts of hydroxypropyl methylcellulose (trade name "Metolose 90SH-100", manufactured by Shin-Etsu Chemical Co., Ltd.) and water were then placed in a stainless steel container and mixed. The mixture was gradually added to the container and reacted for 15 minutes using a homogenizer. This resulted in the formation of crosslinked polyurethane microparticles, yielding an emulsion containing crosslinked polyurethane microparticles. The resulting emulsion was stable without any separation, and the average dispersed particle size of the dispersoid was 5 μm.

[0060] <Evaluation> (dispersibility) The crosslinked polyurethane microparticles and hexane were mixed and then manually stirred to prepare a first dispersion. The crosslinked polyurethane microparticles and hexane were then mixed using an ultrasonic disperser at 30 W for 3 minutes to disaggregate the particles, preparing a second dispersion. The volume-average particle diameter (MV1) of the crosslinked polyurethane microparticles in the first dispersion and the volume-average particle diameter (MV2) of the crosslinked polyurethane microparticles in the second dispersion were measured using a particle size distribution analyzer (product name "MT3300II" manufactured by Microtrac-Bell). The "MV1 / MV2" ratio was then calculated, and the dispersibility of the crosslinked polyurethane microparticles was evaluated according to the following criteria. A larger "MV1 / MV2" ratio indicates a tendency for aggregation (larger apparent particle diameter). The results are shown in the lower part of Tables 2-1 and 2-2. ○: The value of "MV1 / MV2" was less than 1.2. △: The value of "MV1 / MV2" was between 1.2 and 2.0. ×: The value of "MV1 / MV2" was more than 2.0.

[0061] (Biomass ratio) Using an accelerator mass spectrometer, carbon-12( 12 C) and carbon-14 ( 14 The abundance ratio of C) was measured. 12 C and 14 The biomass ratio (%) of the crosslinked polyurethane microparticles was calculated from the abundance ratio of C. The results are shown in the lower part of Tables 2-1 and 2-2.

[0062] (glass transition temperature) The glass transition temperature Tg (°C) of the crosslinked polyurethane microparticles was measured using a differential scanning calorimeter (trade name "DSC-60A", manufactured by Shimadzu Corporation). The results are shown in the lower part of Tables 2-1 and 2-2. Crosslinked polyurethane microparticles were obtained in the same manner as in Example 1, except that the amount of aliphatic polyol B (1,3-propanediol) relative to the total amount of polyester polyol, isocyanate compound, and aliphatic polyol B was 15%. The glass transition temperature Tg (°C) of the obtained crosslinked polyurethane microparticles was -20°C.

[0063] (10% compressive strength) The 10% compressive strength (MPa) of the crosslinked polyurethane microparticles was measured using a microcompression tester (product name "MCT-511", manufactured by Shimadzu Corporation). The 10% compressive strength is the force (MPa) required to crush the crosslinked polyurethane microparticles by 10%, with a smaller value indicating softer particles. The results are shown in the lower part of Tables 2-1 and 2-2.

[0064] (Hydrolysis resistance) The crosslinked polyurethane microparticles were placed in a thermo-hygrostat chamber set at a temperature of 70°C and a humidity of 95%, and left for 8 weeks. After leaving the microparticles, the condition was observed, and the hydrolysis resistance of the crosslinked polyurethane microparticles was evaluated according to the following evaluation criteria. The results are shown in the lower part of Tables 2-1 and 2-2. ○: Remained in the initial state (fine particle state). △: Aggregated and solidified. ×: Liquefaction occurred.

[0065] TIFF0007734255000003.tif105170

[0066] TIFF0007734255000004.tif114170

[0067] <Paint preparation> (Examples 8 to 14, Comparative Examples 7 to 12) The crosslinked polyurethane microparticles obtained in Examples 1 to 7 and Comparative Examples 1 to 6, polyurethane water dispersion (trade name "Rezamin D-6065NP", manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., solids content 30%), additive (trade name "Rezamin D-340 Leveling Agent", manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., solids content 100%), and water were blended in the proportions (unit: parts) shown in Table 3 to prepare a paint with a solids content of 30%.

[0068] <Evaluation> (Coating film low temperature flexibility) The prepared coating material was applied to a PVC sheet using a bar coater. It was then dried in a dryer at 120°C for 1 minute, yielding a test sheet with a 10 μm thick coating film. Test pieces measuring 50 mm wide and 150 mm long (evaluation range: 100 mm) were cut from the resulting test sheet. A flex test was conducted using a Demattia testing machine (model number "NO. 119-L DEMATTYIA FLEXIMG TESTER", manufactured by Yasuda Seiki Seisakusho Co., Ltd.) at a temperature of -10°C and a flex range of 72 to 108%, in which case the low-temperature flexibility of the coating film was evaluated according to the following evaluation criteria. The results are shown in Table 3. ○: Did not break even after being bent 30,000 times. △: Did not break even after being bent 10,000 times. ×: Cracked after 10,000 flexes.

[0069] TIFF0007734255000005.tif126170 [Industrial Applicability]

[0070] The crosslinked polyurethane microparticles of the present invention are useful as a material for forming automotive interior materials such as instrument panels, surface materials for furniture, and also surface materials for sundries that come into close contact with the skin, such as headphones.

Claims

1. The reaction product is obtained by reacting raw materials containing a polyester polyol having structural units derived from a dicarboxylic acid having 8 or more carbon atoms and structural units derived from an aliphatic polyol A, and an isocyanate compound in a state where the raw materials are dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer, the aliphatic polyol A is a branched-chain polyol having a branched structure or a linear polyol having 5 or less carbon atoms, The polyester polyol has a hydroxyl value of 80 to 200 mgKOH / g.

2. the dicarboxylic acid and the aliphatic polyol A are both biomass-derived compounds, 2. The crosslinked polyurethane microparticles according to claim 1, wherein the biomass ratio is 50% by mass or more.

3. 2. The crosslinked polyurethane particles according to claim 1, wherein at least one of the polyester polyol and the isocyanate compound is a tri- or higher functional compound.

4. 2. The crosslinked polyurethane particles according to claim 1, wherein the isocyanate compound is at least one of an aliphatic diisocyanate and a derivative thereof.

5. 2. The crosslinked polyurethane particles according to claim 1, wherein the isocyanate compound is 1,5-pentamethylene diisocyanate or an isocyanurate of 1,5-pentamethylene diisocyanate.

6. 2. The crosslinked polyurethane particles according to claim 1, wherein the dicarboxylic acid has 12 or less carbon atoms.

7. the liquid medium is an organic solvent, 2. The crosslinked polyurethane microparticles according to claim 1, wherein the dispersion stabilizer is a polyurea colloidal particle composed of a solvated portion solvated in the organic solvent and a non-solvated portion not solvated in the organic solvent.

8. the liquid medium is an aqueous liquid medium containing water, 2. The crosslinked polyurethane particles according to claim 1, wherein the dispersion stabilizer is a surfactant.

9. The raw material further contains an aliphatic polyol B, 2. The crosslinked polyurethane particles according to claim 1, wherein the amount of the aliphatic polyol B is 0.1 to 10% by mass based on the total amount of the polyester polyol, the isocyanate compound, and the aliphatic polyol B.

10. 2. The crosslinked polyurethane particles according to claim 1, which have a volume average particle size of 0.1 to 500 μm.

11. The glass transition temperature is −30° C. or lower, 2. The crosslinked polyurethane particles according to claim 1, which have a 10% compressive strength of 1.0 MPa or less.

12. The method includes a step of reacting raw materials containing a polyester polyol having a structural unit derived from a dicarboxylic acid having 8 or more carbon atoms and a structural unit derived from an aliphatic polyol A, and an isocyanate compound in a state where the raw materials are dispersed in the form of fine particles in a liquid medium containing a dispersion stabilizer, to form crosslinked polyurethane fine particles as a reaction product, the aliphatic polyol A is a branched-chain polyol having a branched structure or a linear polyol having 5 or less carbon atoms, The method for producing crosslinked polyurethane microparticles, wherein the polyester polyol has a hydroxyl value of 80 to 200 mgKOH / g.

13. A paint containing the crosslinked polyurethane fine particles according to any one of claims 1 to 11.

14. Further containing a synthetic resin, 14. The paint according to claim 13, wherein the content of the crosslinked polyurethane fine particles is 10 to 100 parts by mass per 100 parts by mass of the synthetic resin.

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