JP2011122034A - Polyurethane resin emulsion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane resin emulsion that gives a dry coating excellent in solvent resistance and flexibility. <P>SOLUTION: The polyurethane resin emulsion contains a polyurethane resin (U) and water, wherein the polyurethane resin (U) is obtained from a urethane prepolymer (u) with an isocyanate terminal using a polycarbonate polyol as at least one kind of a polyol component, and contains, on a basis of the weight of the polyurethane resin (U), 0.1 to 1.5 wt.% of carboxyl group, 3.0 to 8.0 wt.% of urethane group and 0.1 to 9.0 wt.% of urea group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyurethane resin emulsion.

Conventional polyurethane resin emulsions include self-emulsifying emulsions having a carboxyl group in the polyurethane resin.
For example, the polyester-polyurethane aqueous dispersion (see Patent Document 1) with improved acidity, hydroxyl group and urethane group content to improve flexibility and solvent resistance, and the urea group content and adhesiveness An aqueous polyurethane dispersion (see Patent Document 2) with improved water content has been proposed.
However, in these polyurethane resin emulsions, there is a problem that the flexibility becomes low when the solvent resistance of the dried film is further increased, and it is difficult to achieve both improvement of solvent resistance and maintenance of flexibility. Met.

JP-A-7-247333 JP-A-6-340860

  This invention is made | formed in view of the said problem, and the objective of this invention is providing the polyurethane resin emulsion which provides the dry film which is excellent in solvent resistance and a softness | flexibility.

  The inventor of the present invention has reached the present invention as a result of intensive studies to solve the above-mentioned problems. That is, the present invention is a polyurethane resin emulsion containing a polyurethane resin (U) and water, wherein the polyurethane resin (U) is an isocyanate group-terminated urethane prepolymer (u) using a polycarbonate polyol as at least one polyol component. And 0.1 to 1.5% by weight of carboxyl groups, 3.0 to 8.0% by weight of urethane groups and 0.1 to 9.0% by weight based on the weight of the polyurethane resin (U). % Polyurethane resin emulsion containing urea groups.

The polyurethane resin emulsion of the present invention provides a dry film excellent in solvent resistance without sacrificing flexibility.
In addition, the polyurethane resin emulsion of the present invention is particularly suitable for water-based paint applications, and because of its high flexibility, the impact resistance of the coating film to which the water-based paint is applied becomes good, and because of its high solvent resistance, it is suitable for water-based paints. When an organic solvent is used, the swelling of the urethane resin by the organic solvent is suppressed, and the temporal stability of the water-based paint becomes good.

  The polyurethane resin emulsion of the present invention is a polyurethane resin emulsion containing a polyurethane resin (U) obtained from a urethane prepolymer (u) having at least some of its terminals being isocyanate groups, and water.

  The carboxyl group [—COOH] content in (U) is usually 0.1 to 1.5%, preferably 0.2 to 1.4%, more preferably 0.3, from the viewpoint of the flexibility of the dry film. ˜1.3%, particularly preferably 0.4 to 1.2%. The carboxyl group content in the present invention is defined as a carboxyl group content in which a carboxylate anion group (—COO—) in which a carboxyl group is neutralized is converted from the carboxylate group to a carboxyl group. In the above and the following, “%” represents “% by weight” unless otherwise specified.

The urethane group [—NH—COO ⁻ ] content in (U) is usually 3.0 to 8.0%, preferably 3.5 to 7.9%, more preferably from the viewpoint of the flexibility of the dry film. It is 4.0 to 7.8%, particularly preferably 4.5 to 7.7%.

  The urea group [—NH—CO—NH—] content in (U) is usually 0.1 to 9.0%, preferably 0.2 to 8.0%, from the viewpoint of flexibility of the dried film. Preferably it is 0.3-6.0%, Most preferably, it is 0.4-4.0%.

  The average particle size of (U) is preferably 50 to 300 nm, more preferably 50 to 280 nm, particularly preferably 50 to 260 nm, and most preferably 50 to 250 nm, from the viewpoint of stability of the polyurethane resin emulsion.

  Below, the structure of the polyurethane resin emulsion of this invention and the method of making a carboxyl group, a urethane group, and a urea group into specific content are explained in full detail.

  The polyurethane resin (U) in the present invention is composed of a polyisocyanate component (a1), a polyol component (a2), a hydrophilic group-containing active hydrogen-containing component (a3) and, if necessary, other components (a4).

  As the polyisocyanate component (a1) constituting (U), those used in conventional polyurethanes can be used. (A1) As an aromatic polyisocyanate (a11) having 2 or more isocyanate groups and having 6 to 20 carbon atoms (excluding carbon in the isocyanate group, the same shall apply hereinafter), aliphatic having 2 to 18 carbon atoms Examples thereof include polyisocyanate (a12), alicyclic polyisocyanate (a13) having 4 to 15 carbon atoms, araliphatic polyisocyanate (a14) having 8 to 15 carbon atoms and a modified product (a15) of these polyisocyanates. (A1) may be used alone or in combination of two or more.

  Examples of the aromatic polyisocyanate having 6 to 20 carbon atoms (a11) include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 4, 4'- or 2,4'-diphenylmethane diisocyanate (MDI), crude MDI [crude diaminophenylmethane [condensation product of formaldehyde with an aromatic amine (aniline) or a mixture thereof; diaminodiphenylmethane and a small amount (for example, 5 to 20%) )) With a trifunctional or higher functional polyamine]: Polyaryl polyisocyanate (PAPI)], 4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatobiphenyl 3,3′-dimethyl-4,4′-diisocyanatodiphenylmethane 1,5-naphthylene diisocyanate, 4,4 ', 4 "- triphenylmethane triisocyanate, m- or p- isocyanatophenyl sulfonyl isocyanate.

  Examples of the aliphatic polyisocyanate having 2 to 18 carbon atoms (a12) include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4. -Trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6- And diisocyanatohexanoate.

  Examples of the alicyclic polyisocyanate (a13) having 4 to 15 carbon atoms include isophorone diisocyanate (IPDI), 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, and methylcyclohexylene diisocyanate (hydrogenated TDI). Bis (2-isocyanatoethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5- or 2,6-norbornane diisocyanate, and the like.

  Examples of the araliphatic polyisocyanate (a14) having 8 to 15 carbon atoms include m- or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), and the like. Can be mentioned.

  As the modified polyisocyanate (a15), modified polyisocyanate (urethane group, carbodiimide group, allophanate group, urea group, burette group, uretdione group, uretoimine group, isocyanurate group and / or oxazolidone group-containing modification) A free isocyanate group content is usually 8 to 33%, preferably 10 to 30%, particularly 12 to 29%), for example, modified MDI (urethane modified MDI, carbodiimide modified MDI, trihydrocarbyl phosphate modified MDI, etc.), urethane Examples include modified polyisocyanates such as modified TDI, biuret modified HDI, isocyanurate modified HDI, isocyanurate modified IPDI, urethane modified polyisocyanate [excess polyisocyanate (TDI, MDI etc.) and polyiod Polyols used in the production of free isocyanate-containing prepolymer] obtained by reacting and Le, include low molecular weight polyols described below. Examples of the combination of two or more types include a combination of modified MDI and urethane-modified TDI (isocyanate-containing prepolymer).

  Among these polyisocyanate components (a1), preferred are aliphatic polyisocyanates having 2 to 18 carbon atoms (a12) and alicyclic polyisocyanates having 4 to 15 carbon atoms (a13), and more preferred are carbon atoms. The alicyclic polyisocyanate (a13) having a number of 4 to 15, particularly preferably IPDI and hydrogenated MDI.

  Examples of the polyol component (a2) include a polymer polyol (a21) having a number average molecular weight (hereinafter abbreviated as Mn) of 400 to 5,000 and a low molecular polyol (a22) having a Mn of less than 400.

  Examples of the polymer polyol (a21) include polyester polyols (a212) and polyether polyols (a213) other than polycarbonate polyols (a211) and (a211). In the present invention, the polycarbonate polyol (a211) is an essential component as the polymer polyol (a21).

  Mn of (a21) is usually 400 to 5,000, preferably 500 to 5,000, and more preferably 1,000 to 3,000. Mn can be measured by gel permeation chromatography (hereinafter GPC) using tetrahydrofuran as a solvent and polystyrene as a standard.

  As the polycarbonate polyol (a211), one or more alkylene diols having an alkylene group having 4 to 12 carbon atoms, preferably 6 to 10 carbon atoms, more preferably 6 to 9 carbon atoms, and a low molecular carbonate compound. (For example, a dialkyl carbonate having 1 to 6 carbon atoms in an alkyl group, an alkylene carbonate having an alkylene group having 2 to 6 carbon atoms, a diaryl carbonate having an aryl group having 6 to 9 carbon atoms, and the like) The polycarbonate polyol manufactured by making it be mentioned is mentioned.

  Examples of alkylene diols having an alkylene group having 4 to 12 carbon atoms include linear alkylene diols (eg, tetramethylene diol, pentamethylene diol, hexamethylene diol, heptamethylene diol, octamethylene diol, nonamethylene diol, etc.) and branched alkylene diols. (For example, 2-methylpentanediol, 3-methylpentanediol, 2-methylhexanediol, 3-methylhexanediol, 2-methylheptanediol, 3-methylheptanediol, 4-methylheptanediol, 2-methyloctanediol, 3-methyloctanediol, 4-methyloctanediol, etc.), and particularly preferred are tetramethylene diol, pentamethylene diol, hexamethylene diol for straight-chain ones Fine nonamethylene diol, intended for the branch which is 3-methyl-1,5-pentanediol and 2 methyl-1,8-octanediol.

  Examples of the polycarbonate diol (a211) include crystalline polycarbonate diol and amorphous polycarbonate diol. Examples of crystalline polycarbonate diol include “Duranol T6002” (manufactured by Asahi Kasei Chemicals Co., Ltd.), “ETERRNACOLL UH-200”. "Nipporan-980R" (manufactured by Nippon Polyurethane Co., Ltd.), "Placcel CD220" (manufactured by Daicel Corporation), etc., are "PCDL T4672" as an amorphous polycarbonate diol (made by Ube Industries, Ltd.) Asahi Kasei Chemicals Co., Ltd.), “PCDL T5652” (Asahi Kasei Chemicals Co., Ltd.), “Kuraray Polyol C-2090” (Kuraray Co., Ltd.), and the like.

  Examples of the polyester polyol (a212) other than (a211) include condensed polyester polyols and polylactone polyols.

  The condensation type polyester polyol is a polyester polyol obtained by reacting (condensing) a low molecular weight polyol (a22) having a Mn of less than 400, which will be described later, and a polyvalent carboxylic acid or an ester-forming derivative thereof.

  Examples of polycarboxylic acids or ester-forming derivatives thereof include aliphatic dicarboxylic acids (succinic acid, adipic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, etc.), alicyclic dicarboxylic acids (dimer acid, etc.), aromatic Dicarboxylic acids (terephthalic acid, isophthalic acid, phthalic acid, etc.) and trivalent or higher polycarboxylic acids (trimellitic acid, pyromellitic acid, etc.), and their anhydrides (succinic anhydride, maleic anhydride, phthalic anhydride) Acid, trimellitic anhydride, etc.), acid halides thereof (adipic acid dichloride, etc.), low molecular weight alkyl esters (dimethyl succinate, dimethyl phthalate, etc.) and combinations thereof.

  Examples of the condensed polyester polyol include polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyhexamethylene isophthalate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene butylene adipate diol, polybutylene hexamethylene Adipate diol, polydiethylene adipate diol, poly (polytetramethylene ether) adipate diol, poly (3-methylpentylene adipate) diol, polyethylene azelate diol, polyethylene sebacate diol, polybutylene azelate diol, polybutylene sebacate diol , Polyneopentyl terephthalate diol, etc. .

  The polylactone polyol is a polyaddition product of a lactone to a low-molecular polyol (a22) having a Mn of less than 400, which will be described later. Examples thereof include a lactone alone or a mixture of two or more. Examples of the polylactone polyol include polycaprolactone diol, polyvalerolactone diol, and polycaprolactone triol.

  Examples of the polyether polyol (a213) include aliphatic polyether polyols and aromatic ring-containing polyether polyols.

  Examples of the aliphatic polyether polyol include aliphatic low molecular weight active hydrogen atom-containing compounds (divalent to octavalent or higher aliphatic polyhydric alcohols having a hydroxyl group equivalent of 30 to less than 150 and primary or active hydrogen atom-containing groups. An alkylene oxide (hereinafter abbreviated as AO) adduct of a compound containing a secondary amino group can be used.

  The aliphatic polyhydric alcohol to which AO is added includes a linear or branched aliphatic dihydric alcohol [(di) ethylene glycol, (di) propylene glycol, 1,2-, 1,3-, 2,3- Or 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol and 1,12 -Dodecanediol etc.] and alicyclic dihydric alcohol [low molecular diol having a cyclic group, for example, those described in JP-B No. 45-1474], aliphatic trihydric alcohol [glycerin, trimethylolpropane, trialkanolamine, etc. And aliphatic tetravalent or higher alcohols [pentaerythritol, diglycerin, triglycerin, dipentaerythritol, Bit, sorbitan, sorbide, etc.] and the like.

  Examples of the compound containing a primary or secondary amino group to which AO is added include alkyl (carbon number 1 to 12) amine and (poly) alkylene polyamine (alkylene group 2 to 6 carbon atoms, alkylene group number 1 to 1). 4 and the number of polyamines 2 to 5).

  As the aromatic ring-containing polyether polyol, an AO adduct of an aromatic low-molecular-weight active hydrogen atom-containing compound (dihydric to octavalent or higher, phenols and aromatic amines having a hydroxyl group equivalent of 30 to less than 150) is used. it can.

  Examples of phenols to which AO is added include hydroquinone, catechol, resorcin, bisphenol A, bisphenol S, and bisphenol F, and examples of aromatic amines include aniline and phenylenediamine.

  As AO used for manufacture of an AO adduct, C2-C12 or more AO, for example, ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1,2-, 2, Examples include 3- or 1,3-butylene oxide, tetrahydrofuran (THF), α-olefin oxide, styrene oxide, epihalohydrin (such as epichlorohydrin), and combinations of two or more thereof.

  Examples of the aliphatic polyether polyol include polyoxyethylene polyol [polyethylene glycol (hereinafter abbreviated as PEG)], polyoxypropylene polyol [polypropylene glycol (hereinafter abbreviated as PPG), etc.], polyoxyethylene / propylene polyol, and polytetraethylene. And methylene ether glycol (hereinafter abbreviated as PTMG).

  Examples of the aromatic ring-containing polyether polyol include polyols having a bisphenol skeleton, such as EO addition product of bisphenol A [EO2 mol addition product of bisphenol A, EO4 mol addition product of bisphenol A, EO6 mol addition product of bisphenol A, bisphenol A. EO 8 mol adduct, bisphenol A EO 10 mol adduct, bisphenol A EO 20 mol adduct, etc.] and bisphenol A PO adduct [bisphenol A PO 2 mol adduct, bisphenol A PO 3 mol adduct, bisphenol A PO5 molar adducts, etc.] and resorcin EO or PO adducts.

  As the low molecular polyol (a22) having a Mn of less than 400, polyhydric alcohols having 2 to 15 carbon atoms [dihydric alcohols (for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, neo Pentyl glycol, 1,6-hexanediol, 1,8-octanediol, 1,4-cyclohexanedimethanol, diethylene glycol, etc.); trihydric alcohols (eg glycerin, trimethylolpropane, etc.); EO of these polyhydric alcohols and And / or PO low molar adducts (Mn less than 400).

  As (a2), a combination of (a21) and (a21) and a small proportion (for example, 20% or less) of (a22) is preferable. Among (a21), (a211) is preferable, and particularly preferable From the viewpoint of solvent resistance of the dried film, a polycarbonate diol having a Mn of 1,000 to 3,000 is most preferable, and a crystalline polycarbonate diol having a Mn of 1,000 to 3,000 is most preferable.

  As the hydrophilic group-containing active hydrogen-containing component (a3), a dialkyl alkanoic acid having 6 to 24 carbon atoms can be used, for example, 2,2-dimethylolpropionic acid (abbreviated as DMPA), 2,2-dimethylolbutane. An acid, 2, 2- dimethylol heptanoic acid, 2, 2- dimethylol octanoic acid, etc. are mentioned. These salts such as salts of amines (triethylamine, alkanolamine, morpholine, etc.) and / or alkali metal salts (sodium salt, etc.) can also be used.

  Examples of the other component (a4) include a chain extender (a41) and a terminator (a42).

  (A41) includes diamines having 2 to 10 carbon atoms (for example, ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, toluenediamine, piperazine, etc.), polyalkylene polyamines (for example, diethylenetriamine, triethylenetetramine, etc.), hydrazine Alternatively, derivatives thereof (dibasic acid dihydrazide such as adipic acid dihydrazide), amino alcohols having 2 to 10 carbon atoms (such as ethanolamine, diethanolamine, 2-amino-2-methylpropanol, triethanolamine, etc.) and the like can be mentioned.

Examples of (a42) include monoalcohols having 1 to 8 carbon atoms (methanol, ethanol, isopropanol, cellosolves, carbitols, etc.), monoamines having 1 to 10 carbon atoms (monomethylamine, monoethylamine, monobutylamine, dioxygen) Mono- or dialkylamines such as butylamine and monooctylamine; mono- or dialkanolamines such as monoethanolamine, diethanolamine and diisopropanolamine).
The total amount of (a41) and (a42) used is usually 0.8 equivalents or less, preferably 0.7 equivalents or less, based on the equivalent of the NCO group in (a1). Based on the equivalent of the NCO group of (a1), it is usually 0.3 equivalent or less, preferably 0.2 equivalent or less.

  The polyurethane resin (U) in the present invention is preferably a urethane resin obtained from a urethane prepolymer (u) in which at least one of the terminal groups is an isocyanate group.

  The average hydroxyl group equivalent of the hydroxyl group-containing component during the production of (u) is preferably 300 to 1000, more preferably 350 to 950, and particularly preferably 400 to 900.

[Number of charged equivalents of (a1)] / [total number of charged equivalents of (a2) and (a3)] during the production of (u) is preferably 1.20 to 1.90, more preferably 1. 25 to 1.85, particularly preferably 1.30 to 1.80.

In order for the carboxyl group content in (U) of the present invention to be a target value within the scope of the present invention, the amount of (a3) charged during the production of (u) can be set according to the following formula: preferable.
In the following, the unit of weight is g.
Target carboxyl group content (%) = [weight corresponding to COOH based on the charged amount of (a3) / total weight of resin components after emulsion production] × 100
Here, the total weight of the resin components after the emulsion production = (the charge weight other than the solvent at the time of prepolymer production) + (the charge weight of (a4)) + (the weight of water acting as an extender), and elongation The weight of water acting as an agent is calculated by the following formula: (2 molecules of NCO group and 1 molecule of water react)
Weight of water acting as extender = {number of residual NCO equivalents of prepolymer− (number of equivalents of (a4))}
The number of equivalents is the number of moles of the molecule × the average number of functional groups per molecule.

In order to set the urethane group content in (U) as a target value, it is preferable to set the total number of charged equivalents of (a2) and (a3) during the production of (u) according to the following formula.
Target urethane group content (%) = [total number of equivalents of (a2) and (a3) × 59 ÷ total weight of resin components after emulsion production] × 100

In order to set the urea group content in (U) as a target value, it is preferably set according to the following formula from the number of charged equivalents of (a1) used in (u).
Since the amount of urea group produced differs between water extension and amine extension, the following amine extender ratio is defined.
Amine extender ratio = (number of equivalents of (a4)) / (number of equivalents of (a4) + number of equivalents of water acting as extender)
Target urea group content (%) = 100 × [{number of charged equivalents of (a1) −total number of charged equivalents of (a2) and (a3)} × 58 × amine extender ratio] + {(a1) Number of charged equivalents−total number of charged equivalents of (a2) and (a3)} ÷ 2 × 58 × (1-amine extender ratio)] ÷ total weight of resin components after emulsion production

  The production of the prepolymer (u) in the present invention is usually carried out by a reaction at 20 ° C to 150 ° C, preferably 60 ° C to 110 ° C, and the reaction time is usually 2 to 15 hours. The production of (u) can be carried out in the presence or absence of an organic solvent substantially nonreactive with NCO groups. The prepolymer usually has a free NCO group content of 0.1 to 9.0%.

  In the urethanization reaction, in order to promote the reaction, a catalyst used in a normal urethane reaction may be used if necessary. Examples of the catalyst include amine catalysts such as triethylamine, N-ethylmorpholine, triethylenediamine and cycloamidines [1,8-diaza-bicyclo [5,4,0] -7-undecene described in US Pat. No. 4,524,104. (San Apro Co., Ltd., DBU) and the like]; tin-based catalysts such as dibutyltin dilaurate, dioctyltin dilaurate and tin octylate; titanium-based catalysts such as tetrabutyl titanate.

  The polyurethane resin emulsion of the present invention is mixed with an aqueous medium containing a chain extender (a41) and / or a terminator (a42) as necessary after hydrophilizing (neutralizing) (u) as necessary or while making it hydrophilic. Then, a polyurethane resin emulsion can be prepared by carrying out the reaction [chain extension by water or (a41) and / or reaction stop by (a42)] until NCO groups are substantially eliminated. The temperature in mixing and reaction with the aqueous medium is usually 10 ° C to 60 ° C, preferably 20 ° C to 50 ° C.

  The amount of the aqueous medium used is such that the content of the polyurethane resin (U) is 20 to 60%, preferably 30 to 50% based on the weight of the emulsion.

  Hydrophilization (neutralization) may be performed after the production of the polyurethane resin emulsion. When chain extension by (a41) and / or reaction termination by (a42) are performed, (u) is dispersed in an aqueous medium, and then (a41) and / or (a42) is added and (u) and It is preferable to react.

  In addition, (a1) and the active hydrogen-containing component are reacted in the presence of the organic solvent (S) to produce a solution of (u) to react with (a41) and / or (a42), or the presence of the organic solvent By preparing (a1), the above active hydrogen-containing component and optionally (a41) and / or (a42) in one step, the organic solvent solution of (U) is produced and dispersed in an aqueous medium. , (U) polyurethane resin emulsion can also be produced. Also in this case, the hydrophilization (neutralization) may be performed before or after the production of the polyurethane resin emulsion.

  The hydrophilic solvent (S) used in the above reaction and contained in the aqueous medium can be used without any problem as long as it is substantially non-reactive with NCO groups and hydrophilic (water miscible). Examples thereof include ketones such as acetone and ethyl methyl ketone, esters, ethers, amides and alcohols. Of these, acetone is preferred.

  The weight ratio of water to the hydrophilic solvent in the aqueous medium is usually 100/0 to 50/50, preferably 100/0 to 80/20, and particularly preferably 100/0.

  When the hydrophilic solvent contained in (S) and / or the aqueous medium is used, these may be distilled off if necessary after the production of the polyurethane resin emulsion.

  An apparatus for emulsifying and dispersing the polyurethane resin (U), the solvent solution of (U), the urethane prepolymer (u) or the solvent solution of (u) in an aqueous medium is not particularly limited, and examples thereof include an emulsifier of the following method. . 1) Vertical stirring system, 2) Rotor-stator system [for example, “Ebara Milder” (manufactured by Ebara Manufacturing Co., Ltd.)], 3) Line mill system [for example, line flow mixer], 4) Stationary tube mixing Formula [for example, static mixer], 5) Vibration type [for example, “VIBRO MIXER” (manufactured by Chilling Industries Co., Ltd.)], 6) Ultrasonic impact type [for example, ultrasonic homogenizer], 7) High pressure impact type [for example, Gaurin homogenizer (Gaurin)], 8) Emulsification [e.g. membrane emulsification module] and 9) Centrifugal thin film contact [e.g. fillmix]. Of these, 1), 2), 5), 8) and 9) are preferred.

  When chain extension according to (a41) and / or reaction termination according to (a42) is performed, the prepolymer is dispersed in an aqueous medium using a continuous emulsifier [preferably 2) such as Ebara Milder. Next, it is preferable to add (a41) and / or (a42) using a batch type emulsifier [preferably the above 1) vertical stirring method] and mix and react with the prepolymer.

  The solid content concentration of the polyurethane resin emulsion of the present invention is preferably 20 to 60%, more preferably 30 to 50%. In the present invention, “solid content” refers to components other than water.

Hereinafter, a method for preparing an aqueous paint using the polyurethane resin emulsion of the present invention will be described.
In addition to the polyurethane resin emulsion of the present invention, other aqueous resin emulsions or water-soluble resins may be used in combination with the water-based paint, if necessary, for the purpose of assisting the formation of a coating film or improving the binder function.

  Other resin emulsions or water-soluble resins used in combination with water-based paints include, for example, polyurethane resin emulsions other than the polyurethane resin emulsion of the present invention, polyacrylic resin emulsions, polyester resin emulsions, water-soluble polyurethane resins, water-soluble polyacrylic resins and Examples include water-soluble polyester resins. These other resin emulsions or water-soluble resins can be appropriately selected from those commonly used in each application for each application of the water-based paint.

The content of the solid content of the polyurethane resin emulsion of the present invention in the aqueous paint is usually 0.1 to 60%, preferably 1 to 50% based on the weight of the aqueous paint.
Further, the solid content of the other resin emulsion and the water-soluble resin in the aqueous paint is usually 60% or less, preferably 50% or less, based on the weight of the aqueous paint.

  The water-based paint can further contain one or more of a crosslinking agent, a pigment, a pigment dispersant, a viscosity modifier, an antifoaming agent, an antiseptic, a deterioration preventing agent, a stabilizer, an antifreezing agent, and the like.

Examples of the crosslinking agent include water-soluble or water-dispersible amino resins, water-soluble or water-dispersible polyepoxides, water-soluble or water-dispersible polyisocyanate compounds, and polyethylene urea.
The addition amount of the crosslinking agent is usually 0 to 30%, preferably 0.1 to 20%, based on the solid content weight of the aqueous dispersion.

  Examples of the pigment include inorganic pigments having a solubility in water of 1 or less, such as white pigments, black pigments, gray pigments, red pigments, brown pigments, yellow pigments, green pigments, blue pigments, purple pigments and metallic pigments; and organic pigments, For example, natural organic pigment synthetic organic pigments, nitroso pigments, nitro pigments, pigment dye-type azo pigments, azo lakes made from water-soluble dyes, azo lakes made from poorly soluble dyes, lakes made from basic dyes, lakes made from acid dyes, xanthan lakes , Anthraquinone lake, pigments from vat dyes, phthalocyanine pigments, and the like. The pigment content is usually 50% or less, preferably 30% or less, based on the weight of the water-based paint.

  Examples of the pigment dispersant include various surfactants [anionic, cationic, nonionic or amphoteric] and a polymer type emulsifying dispersant (Mn 1,000 to 20,000), preferably a polymer type emulsifying dispersant. It is. The content of the pigment dispersant is usually 20% or less, preferably 15% or less, based on the weight of the pigment.

As viscosity modifiers, thickeners such as inorganic viscosity modifiers (such as sodium silicate and bentonite), cellulose viscosity modifiers (methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, etc., Mn is usually 20,000 or more), Protein (casein, casein soda, casein ammonium, etc.), acrylic (sodium polyacrylate, ammonium polyacrylate, etc., Mn is usually 20,000 or more) and vinyl (polyvinyl alcohol, etc., Mn is usually 20,000 or more) ).
The content of the viscosity modifier is usually 5% or less, preferably 3% or less, based on the weight of the aqueous paint.

  Examples of antifoaming agents include long-chain alcohols (such as octyl alcohol), sorbitan derivatives (such as sorbitan monooleate), and silicone oils (such as polymethylsiloxane and polyether-modified silicone). The content of the antifoaming agent is usually 5% or less, preferably 3% or less, based on the weight of the aqueous paint.

  Examples of the preservative include organic nitrogen sulfur compound-based preservatives, organic sulfur halide-based preservatives, and the like. The content of the preservative is usually 5% or less, preferably 3% or less, based on the weight of the aqueous paint.

  Examples of deterioration inhibitors and stabilizers (ultraviolet absorbers, antioxidants, etc.) include hindered phenols, hindered amines, hydrazines, phosphoruss, benzophenones, and benzotriazoles. The content of deterioration inhibitors and stabilizers (such as UV absorbers and antioxidants) is usually 5% or less, preferably 3% or less, based on the weight of the water-based paint.

Examples of the antifreezing agent include ethylene glycol and propylene glycol.
The content of the antifreezing agent is usually 5% or less, preferably 3% or less, based on the weight of the aqueous paint.

  A solvent may be further added to the water-based paint. Examples of the solvent to be added include monohydric alcohols (methanol, ethanol, propanol, etc.), glycols (ethylene glycol, propylene glycol, diethylene glycol, etc.), trivalent or higher alcohols (GL, etc.), cellosolves (methyl and ethyl cellosolve, etc.) Etc. can be used. The content ratio of the solvent to be added is preferably 20% or less, more preferably 15% or less, based on the weight of the aqueous paint.

  The water-based paint using the polyurethane resin emulsion of the present invention is produced by mixing and stirring the polyurethane resin emulsion of the present invention and the above-described one. When mixing, all components may be mixed at the same time, or each component may be charged and mixed in stages.

  The solid content concentration of the aqueous paint is preferably 10 to 70%, more preferably 15 to 60%.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these. Hereinafter, the part means part by weight.
Example 1
In a simple pressure reaction apparatus equipped with a stirrer and a heater, 287.9 parts of crystalline polycarbonate diol having a Mn of 2,000 [Duranol T6002, manufactured by Asahi Kasei Chemicals Co., Ltd.], 3.6 parts of 1,4 butanediol, DMPA8 .9 parts, hydrogenated MDI 98.3 parts and acetone 326.2 parts were charged while introducing nitrogen. Thereafter, the mixture was heated to 90 ° C. and subjected to urethanization reaction for 8 hours to produce a prepolymer. After cooling the reaction mixture to 40 ° C., 6.8 parts of triethylamine was added and mixed, and further 568.8 parts of water was added and emulsified with a rotor-stator type mechanical emulsifier to obtain an aqueous dispersion. . 28.1 parts of 10% ethylenediamine aqueous solution was added to the obtained aqueous dispersion with stirring, and the mixture was stirred at 50 ° C. for 5 hours to carry out chain elongation reaction. Thereafter, acetone was removed at 65 ° C. under reduced pressure to obtain a polyurethane resin emulsion (No. 1).

Examples 2-6 and Comparative Examples 1-3
In the same manner as in Example 1, using the raw materials listed in Table 1, the polyurethane resin emulsions Nos. 2 to 6 and Comparative Examples 1 to 3 in Comparative Examples 1 to 3 were used. 2-No. 9 was produced. “PCDL T4672” (manufactured by Asahi Kasei Chemicals Corporation) is an amorphous polycarbonate diol having an Mn of 2,000, and “PTMG2000” (manufactured by Mitsubishi Chemical Corporation) is a polytetramethylene glycol having an Mn of 2,000. Table 1 shows the carboxyl group content, urethane group content, urea group content, and average particle diameter of the urethane resin emulsion in the urethane resin in the obtained polyurethane resin emulsion.

Table 2 shows the results of evaluating the solvent resistance and embrittlement temperature of these polyurethane resin emulsions based on the following evaluation methods.
<Solvent resistance>
This was performed based on the method described in JIS K7114. The measurement sample was obtained by casting a polyurethane resin emulsion into a film shape, drying at 105 ° C. for 3 hours with a circulating drier, and then cutting out a square test piece (4 cm × 4 cm × thickness 0.2 mm). . N-Heptane or toluene was used as a test solution. The test piece was immersed in a test solution at 23 ° C. for 24 hours, the increase in the length of two sides before and after immersion of the test piece was measured to obtain an average value, and the rate of change was obtained from the following equation.
Rate of change (%) = [(length after immersion−length before immersion) ÷ length before immersion] × 100
The smaller the rate of change, the better the solvent resistance.
<Brittle temperature>
This was performed based on the method described in JIS K7216. The measurement sample was cast from a polyurethane resin emulsion into a film, dried at 105 ° C for 3 hours and dried in a circulating dryer, and then cut (4 cm x 0.6 cm x thickness 0.2 mm). Methanol was used as the medium. The lower the embrittlement temperature, the better the flexibility.

Evaluation Example 1 [Evaluation as water-based paint]
90 parts of ion-exchanged water, 70 parts of thickener [“Biseriser AP-2”, manufactured by Sanyo Chemical Industries, Ltd.], 10 parts of pigment dispersant [“Calibon L-400”, manufactured by Sanyo Chemical Industries, Ltd.] In addition, 140 parts of titanium oxide [“CR-93”, manufactured by Ishihara Sangyo Co., Ltd.], carbon black [“FW200P”, manufactured by Degussa Co., Ltd.], and 160 parts of calcium carbonate were mixed and dispersed with a paint conditioner for 30 minutes. Here, 20 parts of 1-nonanol, 200 parts of an acrylic emulsion [“Polytron Z330”, manufactured by Asahi Kasei Co., Ltd.], and the polyurethane resin emulsion No. obtained above were used. 1 was mixed with 200 parts of stirring. Furthermore, it prepared so that it might become a viscosity of 150 mPa * s [25 degreeC, TOKIMEC Co., Ltd. rotational viscometer (60 rpm)] using ion-exchange water, and the aqueous coating material (A-1) was obtained.

  In the same manner as in Evaluation Example 1, polyurethane resin emulsion No. 1 instead of polyurethane resin emulsion No. 1 2-No. 9 was used to produce water-based paints (A-2) to (A-9). Table 3 shows the results of evaluating the storage stability of the water-based paint and the impact resistance of the coating film based on the following evaluation method.

<Storage stability test of water-based paint>
130 g of water-based paint was placed in a glass bottle having an inner diameter of 4.0 cm and a volume of 140 ml, and the appearance (presence / absence of aggregates) and viscosity change after storage at 25 ° C for 24 hours or 20 days were evaluated. The viscosity was measured at 25 ° C. using a rotary viscometer (60 rpm) manufactured by TOKIMEC.

<Impact resistance test of coating film>
The aqueous paint was spray-coated on a 10 cm × 20 cm steel plate and heated at 150 ° C. for 20 minutes to produce a 25 μm coating film. Using this coated steel sheet, an impact resistance test was performed with a load of 500 g using a DuPont system in accordance with JIS K-5600-5-3, and the following evaluation criteria were used.
(Double-circle): The crack of the coating-film surface after a test is very slight.
○: There are few scratches on the coating film surface after the test.
(Triangle | delta): Although the crack of the coating-film surface after a test is large, the steel plate is not exposed.
X: The state in which the scratches on the coating film surface after the test are large and the steel sheet is exposed.

  The polyurethane resin emulsion of the present invention is used for water-based paints for automobiles, building materials, household appliances, plastics, etc., and for adhesives and textile processing (for pigment printing, for nonwoven fabrics, reinforcing fiber sizing agent and antibacterial agent). Can be used as a polyurethane resin emulsion.

Claims (5)

  A polyurethane resin emulsion containing a polyurethane resin (U) and water, wherein the polyurethane resin (U) is obtained from an isocyanate group-terminated urethane prepolymer (u) using a polycarbonate polyol as at least one polyol component, And 0.1 to 1.5% by weight of carboxyl group, 3.0 to 8.0% by weight of urethane group and 0.1 to 9.0% by weight of urea group based on the weight of the polyurethane resin (U). Contains polyurethane resin emulsion.   The polyurethane resin emulsion according to claim 1, wherein the polycarbonate polyol is a crystalline polycarbonate diol.   The polyurethane resin emulsion according to claim 1 or 2, wherein the urethane prepolymer (u) is a urethane prepolymer obtained by using isophorone diisocyanate and / or 4,4-dicyclohexylmethane diisocyanate.   The polyurethane resin emulsion according to any one of claims 1 to 3, wherein the polyurethane resin (U) has an average particle size of 50 to 300 nm.   The polyurethane resin emulsion according to any one of claims 1 to 4, which is used for water-based paints.