JP2007277326A - Method for producing aqueous dispersion of polyurethane resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing aqueous dispersion of polyurethane resin free from organic solvents, excellent in physical properties of a dried film, and to provide an aqueous dispersion of the polyurethane resin obtained by the same. <P>SOLUTION: The invention relates to the method for producing aqueous dispersion (Q2) of polyurethane resin composed of a polyurethane resin with 0.01-5 μm of volume average particle size comprising a step obtaining an aqueous dispersion (Q1) of polyurethane resin with 0.1-100 μm of volume average particle size by dispersing a solid polyurethane prepolymer with more than 0.5 wt.% of terminal isocyanate groups which is obtained without using organic solvents, by using one or more kinds of dispersing/mixing devices (A1) at a temperature below melting point of the polyurethane prepolymer in water, and a step dispersing the product dispersion using one or more kinds of dispersing/mixing devices (A2) with a different dispersing system from the dispersing/mixing device (A1) at a temperature below melting point of the polyurethane prepolymer to disperse until the dispersion has 1/2-1/1,000 of volume average particle size. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing an aqueous polyurethane resin dispersion and an aqueous polyurethane resin dispersion obtained.

Polyurethane resin aqueous dispersions are used in the paint, adhesive, binder and coating agent fields as highly functional aqueous dispersions due to their excellent durability, chemical resistance, abrasion resistance and other performances. Are also becoming increasingly important from the viewpoints of environmental conservation, resource saving, safety, and the like.
These polyurethane resin aqueous dispersions may be produced by dispersing an isocyanate group-terminated urethane prepolymer in water and extending the chain with a diamine (so-called prepolymer mixing method) (Patent Documents 1 to 3), and isocyanate. There is a method in which a polyurethane resin (dead polymer) containing almost no groups is dispersed in water.
The former is a method of dispersing in the state of a urethane prepolymer in order to reduce the viscosity when the supply resin is melted in the dispersion step when a relatively high molecular weight polyurethane resin is obtained. Although there is a method of diluting with an organic solvent to lower the melting temperature, it is not preferable in terms of odor and safety. Therefore, a method that does not use a solvent has been proposed.
However, any method that does not use an organic solvent is a method of melting at a temperature equal to or higher than the melting temperature of the urethane prepolymer, and the aqueous dispersion obtained is dried by contacting and dispersing with an aqueous medium at such a temperature. There was a problem that the physical properties of the coating were insufficient.
Japanese Patent Laid-Open No. 2004-2732 JP 2004-59676 A JP 2004-307721 A

  An object of the present invention is to provide a method for producing a polyurethane resin aqueous dispersion that does not use an organic solvent and is excellent in physical properties of a dry film, and a polyurethane resin aqueous dispersion obtained thereby. .

  As a result of studying the cause of the above problems, the present inventors have found that a urethane prepolymer having a relatively high molecular weight has a relatively high melting temperature. Therefore, the urethane prepolymer is melted at a temperature higher than the melting temperature by an extruder or the like. However, when dispersed in an aqueous medium, it was found that decomposition and deterioration occur due to contact between the urethane prepolymer and water at a high temperature, and as a result, the physical properties of the dried film are lower than expected. As a result of further studies, the present inventors have found a method for producing a polyurethane resin aqueous dispersion capable of solving the above-described problems.

  That is, the present invention provides a solid polyurethane prepolymer (U) obtained without using an organic solvent and having a terminal isocyanate group content of more than 0.5% by weight using one or more dispersion mixers (A1). After being dispersed in water at a temperature lower than the melting temperature of the polymer (U) to obtain a polyurethane resin aqueous dispersion (Q1) comprising a polyurethane resin (U1) having a volume average particle size of 0.1 to 100 μm, The volume average particle diameter of the polyurethane resin (U1) is 1 at a temperature lower than the melting temperature of the polyurethane prepolymer (U) using one or more dispersion mixing apparatuses (A2) having a different dispersion method from the dispersion mixing apparatus (A1). Polyurethane resin comprising a polyurethane resin having a volume average particle size of 0.01 to 5 μm, wherein the polyurethane resin is dispersed to a volume average particle size of / 2 to 1/100 It is the manufacturing method of a fat-and-water dispersion (Q2), and the polyurethane resin water dispersion (Q2) manufactured by this manufacturing method.

The method for producing the polyurethane resin aqueous dispersion of the present invention comprises:
(1) Since no organic solvent is used, it is excellent in low environmental load, safety and low odor.
(2) An aqueous dispersion excellent in dispersion stability can be obtained.
(3) An aqueous dispersion having excellent physical properties of the dry film can be obtained.

  In the process of producing the polyurethane prepolymer (U) in the present invention (hereinafter sometimes simply referred to as (U)) and the process of dispersing the (U) in water, no organic solvent is used. Therefore, the polyurethane resin aqueous dispersion obtained by the production method of the present invention contains substantially no organic solvent.

  Moreover, the polyurethane prepolymer (U) in the present invention is an amount in which the terminal isocyanate group content exceeds 0.5% by weight based on the weight of the polyurethane prepolymer (U), preferably 0.7 to 5% by weight, More preferably, it is 0.9 to 4% by weight.

In the production method of the present invention, in the process of dispersing the urethane prepolymer (U), which is a dispersion, in water, using two or more types of dispersion mixing apparatuses having different dispersion modes, the temperature is lower than the melting temperature of the resin. Since the dispersion is performed, the dispersion is mixed in two or more stages by using two or more kinds of dispersion mixing apparatuses having different dispersion modes without melting the resin.
By carrying out such a dispersion step, the desired fine particles can be dispersed at a temperature lower than the melting temperature, and the polyurethane resin in the obtained polyurethane resin aqueous dispersion is less decomposed and deteriorated, and its dry film properties are low. Are better.
With only one type of dispersion mixing apparatus, it is difficult to disperse to the target volume average particle diameter, and an aqueous dispersion having sufficiently stable and excellent dry film properties cannot be obtained.

The melting temperature of the urethane prepolymer (U) in the present invention is preferably 70 to 280 ° C., more preferably 100 to 220 ° C., most preferably 130 to 200, from the viewpoint of the resin physical properties of the dry film of the polyurethane resin aqueous dispersion. ° C.
The melting temperature in the present invention is JIS K7210 (plastic-thermoplastic melt mass flow rate test method) using a “melt indexer type I” (manufactured by Tester Sangyo Co., Ltd.) as a melt mass flow rate measuring device. , Load 2.16kg
The temperature at which the melt mass flow becomes 10 g / 10 min.

  In the urethane prepolymer (U) in the present invention, the polyol (a) and the polyisocyanate (b) are essential components, and if necessary, a compound (c) containing a hydrophilic group and an active hydrogen atom-containing group is used. Manufactured.

The polyol (a) includes a high molecular weight polyol (a1) having a hydroxyl group equivalent (number average molecular weight per hydroxyl group calculated from the number average molecular weight and hydroxyl value) of 150 or more, and a low molecular polyol (a2) having a hydroxyl group equivalent of less than 150. ).
In the present invention, the number average molecular weight (hereinafter abbreviated as Mn) of the polyol is measured by gel permeation chromatography (GPC) using polyethylene glycol as a standard. However, the number average molecular weight of the low molecular polyol is a calculated value from the chemical formula.

  Examples of the polymer polyol (a1) having a hydroxyl equivalent weight of 150 or more include polyether polyol (a11) and polyester polyol (a12).

  Examples of (a11) include aliphatic polyether polyols and aromatic ring-containing polyether polyols.

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

  As the aromatic polyether polyol, a polyol (a121) having a bisphenol skeleton, for example, an EO adduct of bisphenol A [EO2 mol adduct of bisphenol A, EO4 mol adduct of bisphenol A, EO6 mol adduct of bisphenol A, bisphenol EO 8 mol adduct, bisphenol A EO 10 mol adduct, bisphenol A EO 20 mol adduct, etc.] and bisphenol A PO adduct [bisphenol A PO2 mol adduct, bisphenol A PO3 mol adduct, bisphenol A PO5 mol adducts, etc.], and EO or PO adduct (a122) of resorcinol.

  The polyether polyol (a11) undergoes ring-opening addition reaction of AO to an aliphatic or aromatic low molecular weight active hydrogen atom-containing compound in the presence of an addition catalyst (a known catalyst such as an alkali metal hydroxide or a Lewis acid). Can be obtained.

Mn of (a11) is usually 300 or more, preferably 300 to 10,000, more preferably 300 to 6,000.
The hydroxyl equivalent of (a11) is usually 150 or more, preferably 150 to 5,000, more preferably 150 to 3,000.

  Examples of the polyester polyol (a12) include condensed polyester, polylactone polyol, polycarbonate polyol, and castor oil-based polyol.

The condensed polyester is a polyester of a low molecular weight (Mn 300 or less) polyhydric alcohol and a polyvalent carboxylic acid or an ester-forming derivative thereof.
Low molecular weight polyhydric alcohols include dihydric to octahydric or higher aliphatic polyhydric alcohols having a hydroxyl group equivalent of 30 to less than 150 and dihydric to octavalent or higher phenols having a hydroxyl group equivalent of 30 to less than 150. AO low molar adducts can be used.
Of the low molecular weight polyhydric alcohols that can be used in the condensation type polyester, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexane glycol, bisphenol A EO or PO low mole Adducts, and combinations thereof.
Examples of polyvalent carboxylic acids or ester-forming derivatives thereof that can be used in condensed polyesters include aliphatic dicarboxylic acids (succinic acid, adipic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, etc.), alicyclic dicarboxylic acids ( Dimer acid), aromatic dicarboxylic acid (terephthalic acid, isophthalic acid, phthalic acid etc.) and trivalent or higher polycarboxylic acid (trimellitic acid, pyromellitic acid etc.), and their anhydrides (succinic anhydride, Maleic anhydride, phthalic anhydride, trimellitic anhydride, etc.), these acid halides (such as adipic acid dichloride), these low molecular weight alkyl esters (such as dimethyl succinate, dimethyl phthalate), and combinations thereof. .

  Examples of the condensation type polyester 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, Examples thereof include polyneopentyl terephthalate diol.

A polylactone polyol is a polyaddition product of a lactone to a low molecular weight polyhydric alcohol. As the lactone, a lactone having 4 to 12 carbon atoms can be used, and examples thereof include 4-butanolide, 5-pentanolide, and 6-hexanolide. It is done.
Examples of the polylactone polyol include polycaprolactone diol, polyvalerolactone diol, and polycaprolactone triol.

The polycarbonate polyol is a polyaddition product of an alkylene carbonate to a low molecular weight polyhydric alcohol. As the alkylene carbonate, an alkylene carbonate having 2 to 8 carbon atoms can be used, and examples thereof include ethylene carbonate and propylene carbonate. Two or more of these may be used in combination.
Examples of the polycarbonate polyol include polyhexamethylene carbonate diol.
Examples of commercially available polycarbonate polyols include NIPPOLAN 980R [Mn = 2,000, manufactured by Nippon Polyurethane Industry Co., Ltd.], T5652 [Mn = 2,000, manufactured by Asahi Kasei Co., Ltd.] and T4672 [Mn = 2,000, Asahi Kasei. Made by Co., Ltd.].

The castor oil-based polyol includes castor oil and castor oil modified with polyol or AO.
Modified castor oil can be produced by transesterification of castor oil and polyol and / or AO addition.
Castor oil-based polyols include castor oil, trimethylolpropane-modified castor oil, pentaerythritol-modified castor oil, EO (4 to 30 mol) adduct of castor oil, and the like.

  Of the polyester polyol (a12), preferred are condensed polyester and polycarbonate polyol.

Examples of the low molecular weight polyol (a2) having a hydroxyl group equivalent of less than 150 include aliphatic dihydric alcohols, aliphatic trihydric alcohols, and aliphatic tetrahydric or higher alcohols.
Of these, (a2) is preferably a dihydric or trivalent aliphatic alcohol from the viewpoint of water resistance and heat-resistant yellowing, and examples of the aliphatic dihydric alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, Neopentyl glycol and 1,6-hexanediol are particularly preferred, and trimethylolpropane is particularly preferred as the aliphatic trihydric alcohol.

As the polyisocyanate (b), which is another essential component of the urethane prepolymer (U), those conventionally used for producing polyurethane resins can be used.
As polyisocyanate (b), aromatic polyisocyanate (b1) having 2 to 3 or more isocyanate groups and having 6 to 20 carbon atoms (excluding carbon in NCO group, the same shall apply hereinafter), having 2 to 2 carbon atoms. 18 aliphatic polyisocyanate (b2), alicyclic polyisocyanate (b3) having 4 to 15 carbon atoms, and araliphatic polyisocyanate (b4) having 8 to 15 carbon atoms.

  Examples of the aromatic polyisocyanate (b1) include 1,3- and / or 1,4-phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate (TDI), 4,4′- and / or / Or 2,4′-diphenylmethane diisocyanate (MDI), 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- and p-isocyanatophenylsulfonyl isocyanate and the like.

Examples of the aliphatic polyisocyanate (b2) include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, Lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate Etc.

Examples of the alicyclic polyisocyanate (b3) include isophorone diisocyanate (IPDI), 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), and bis (2-isocyanate). Natoethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5- and / or 2,6-norbornane diisocyanate.

  Examples of the araliphatic polyisocyanate (b4) include m- and / or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), and the like.

  Of these, (b2) and (b3) are preferred, (b3) is more preferred, and IPDI and hydrogenated MDI are particularly preferred.

The urethane prepolymer (U) in the present invention is produced using a compound (c) containing a hydrophilic group and an active hydrogen atom-containing group, if necessary.
(C) has a hydrophilic group for stably dispersing the urethane prepolymer (U) in water, and has an activity such that it is incorporated into the molecular chain of the polyurethane resin by reaction with the polyisocyanate (b). It is a compound having one, preferably 2 to 3, hydrogen atom-containing groups in one molecule.
Examples of the hydrophilic group in (c) include a carboxyl group, a sulfonic acid group, a phosphoric acid group, and a group consisting of a neutralized salt thereof.
Examples of the neutralized salt include alkali metal salts (such as sodium salts and potassium salts), ammonium salts, quaternary ammonium salts, and tertiary amine salts (for example, triethylamine salts, alkanolamine salts, and morpholine salts).
Among (c), preferred are those having a hydrophilic group comprising a quaternary ammonium salt of a carboxylic acid or sulfonic acid, particularly a hydrophilic group comprising a tertiary amine salt of a carboxylic acid.
Examples of (c) include dialkyrol alkanoic acids having 6 to 24 carbon atoms and neutralized salts thereof, such as 2,2-dimethylolpropionic acid (hereinafter sometimes abbreviated as DMPA), 2 2,2-dimethylolbutanoic acid, 2,2-dimethylolheptanoic acid and 2,2-dimethyloloctanoic acid, and neutralized salts thereof.
By using (c), a carboxyl group can be introduced into the urethane prepolymer (U), so that the aqueous dispersion tends to be stable.
In addition, (c) is a dispersion process for producing a polyurethane resin in an acid form and producing a polyurethane resin aqueous dispersion (Q1) described later. In the water used, a neutralizer (tertiary amine, alkali metal hydroxide) is used. Or the like) may be dissolved in advance, and the acid of (c) may be neutralized at the same time as the dispersion to form a salt form.
The amount of (c) used is preferably such that the hydrophilic group content based on the weight of the urethane prepolymer (U) is 5% by weight or less, particularly preferably 0.5 to 3.0% by weight. Is the amount used.

  In addition to the above, the raw material of the urethane prepolymer (U) in the present invention includes a chain extender, a crosslinking agent, a reaction terminator, a catalyst, an antioxidant, a coloring inhibitor, a retarder, a plasticizer, or a release agent. Can be used.

The urethane prepolymer (U) in the present invention is 50 to 250 ° C., preferably 100 to 250 ° C., more preferably 150 to 250 ° C., most preferably 180 to 220 ° C. in the absence of an organic solvent. And it is preferable that it is a urethane prepolymer obtained by making urethanation reaction of a polyol (a) and a polyisocyanate (b).
In the urethane prepolymer (U) in the present invention, in order to increase the content of the terminal isocyanate group to 0.5% by weight or more, the following method may be mentioned.

(1) A method in which the number of equivalents of polyisocyanate (b) is excessive compared to the number of equivalents of polyol (a).
(2) In the urethanization reaction, before the whole amount of isocyanate groups is consumed, the method moves to a dispersion step.

The Mn of the urethane prepolymer (U) in the present invention [measured by GPC based on standard polystyrene] is usually 2,000 in the case of a non-crosslinked type (thermoplastic: a type that does not use a crosslinking agent). ˜2,000,000 or more, preferably 5,000 to 500,000, in particular 10,000 to 100,000. (U) of the crosslinking type (a type using a crosslinking agent) may have a Mn higher than the above range or a high Mn that cannot be measured by GPC.
The content of the hydrophilic group (the hydrophilic group derived from the above (c)) in the urethane prepolymer (U) of the present invention is preferably 5% by weight or less based on the weight of the urethane prepolymer (U). More preferably, it is 0.5 to 3.0% by weight.

  The reaction vessel for performing the urethanization reaction is not a problem as long as it is a stirrable reaction vessel, but it is preferable to use a single-screw or twin-screw extruder from the viewpoint of stirring strength, hermeticity, and heating ability. Examples of the uniaxial or biaxial extruder include a continuous kneader (manufactured by Kurimoto Seiko Co., Ltd.) and a uniaxial kneader.

Below, this invention is demonstrated further in detail by showing the dispersion | distribution method of urethane prepolymer (U).
The method for producing a polyurethane water dispersion of the present invention is a method of dispersing the urethane prepolymer (U) in two or more stages.
First, the first dispersion is a polyurethane having a volume average particle diameter of 0.1 to 100 μm by dispersing in water at a temperature lower than the melting temperature of the urethane prepolymer (U) using one or more dispersion mixing devices (A1). This is a step of obtaining an aqueous polyurethane resin dispersion (Q1) comprising the resin (U1).

The urethane prepolymer (U) after the urethanization reaction is usually in a molten liquid state or solid state, but in the method for producing an aqueous dispersion of the present invention, even in the molten liquid state, it is once cooled to a solid state, It is preferable from the viewpoint of suppressing the decomposition of (U) that the solid material is supplied to the dispersion mixing device (A1).
In order to introduce (U) into the dispersion mixing apparatus (A1) together with water, the volume average particle size is previously set to a size of 0.2 to 20 mm (preferably 0.2 to 10 mm, particularly preferably 0.2 to 3 mm). It is preferable to adjust to a solid particle shape (at 25 ° C.) from the viewpoint of efficient dispersion.

The volume average particle diameter in the present invention is determined by using a laser diffraction particle size distribution measuring device [for example, LA-750 (manufactured by Horiba Seisakusho)] or a light scattering particle size distribution measuring device [for example, ELS-8000 (manufactured by Otsuka Electronics Co., Ltd.)]. Can be measured.
The number average particle diameter can also be measured by the same measurement method.

As means for adjusting the urethane prepolymer (U) to solid particles, for example, means for cutting, pelletizing, granulating, or pulverizing can be used. The adjustment to the solid particles can be carried out in water or in the absence of water.
For example, the urethane prepolymer (U) rolled into a sheet shape is cut into a strip shape with a strand cutter and then made into particles with a rotary blade.

The urethane prepolymer (U) adjusted to solid particles is introduced into the dispersion mixing device (A1) together with water. As the dispersion mixing device (A1), a rotary dispersion mixing device and a media type dispersion mixing are used. It is preferable to use one or more selected from the apparatus from the viewpoint of good efficiency in the dispersion of the solid particulate (U) of 0.2 to 20 mm.
The main dispersion principle of the dispersion mixing device (A1) is that the particles are pulverized and dispersed by applying a shearing force to the particles from the outside by rotation of the drive unit or the like. (A1) can be operated at normal pressure or under pressure, but is normally operated at normal pressure.

  As a rotary dispersion mixing apparatus, for example, TK homomixer (manufactured by PRIMIX Co., Ltd.), CLEARMIX (manufactured by MTechnic Co., Ltd.), FILMIX (manufactured by PRIMIX Corporation), Ultra Turrax (manufactured by IKA), Examples are Ebara Milder (manufactured by Ebara Seisakusho), Cavitron (manufactured by Eurotech) and biomixer (manufactured by Nippon Seiki).

  Examples of the media type dispersion mixing apparatus include a colloid mill (manufactured by IKA), a corn mill (manufactured by IKA), a dyno mill (manufactured by IKA), a bead mill, and a roll mill.

  As the dispersion mixing device (A1), two or more types of devices selected from these rotary dispersion mixing devices and media type dispersion mixing devices may be connected in series and used together.

The temperature when passing through the dispersion mixing apparatus (A1) is less than the melting temperature of the urethane prepolymer (U), preferably the melting temperature, from the viewpoint of preventing decomposition or deterioration of the urethane prepolymer (U) as a dispersion. From the viewpoint of dispersion efficiency and suppression of decomposition / deterioration, a temperature lower than 5 ° C. and a temperature higher than room temperature, more preferably a temperature lower than the melting temperature by 10 ° C.
The weight ratio of the urethane prepolymer (U) and water supplied to the dispersion mixing apparatus (A1) is appropriately selected depending on the resin component content of the target aqueous dispersion. Usually, (U) / water = The ratio is 10/2 to 100, preferably 10/5 to 50.
Moreover, the residence time in the dispersion mixing apparatus of (U) and water is 0.1-30 minutes normally, Preferably it is 1-5 minutes.

  When performing dispersion in the dispersion mixing apparatus (A1), if necessary, from a pH adjuster, a foam breaker, a foam suppressor, a defoamer, an antioxidant, a colorant, a plasticizer, and a mold release agent. One or more selected can be added. Moreover, you may concentrate or dilute after dispersion | distribution as needed.

  By passing through the dispersion mixer (A1), the urethane prepolymer (U) having a volume average particle size of 0.2 to 20 mm is converted into a volume average particle size of 0.1 to 100 μm (preferably 0.1 to 30 μm, more preferably Can be dispersed in a polyurethane resin (U1) of 0.1 to 10 μm, more preferably 0.1 to 3 μm, and most preferably 0.1 to 1 μm, to obtain an aqueous polyurethane resin dispersion (Q1).

In the second dispersion step of the present invention, the polyurethane resin aqueous dispersion (Q1) obtained as described above is one or more types of dispersion mixing apparatus (A2) having a different dispersion method from the dispersion mixing apparatus (A1). It is a process of introducing into and further finely dispersing.
Even if dispersed only with (A1), it can be dispersed to a certain volume average particle diameter, but in order to further finely disperse in a short time, or the volume average particle diameter / number average particle diameter described later, In order to narrow the particle size distribution and improve the dispersion stability and film-forming property of the aqueous dispersion, it is necessary to further finely disperse with a dispersion device (A2) having a different dispersion method from (A1). is there.
The dispersion mixing device (A2) here is different from (A1) in the dispersion method, that is, the principle, and is preferably a dispersion mixing device suitable for the fine dispersion ability of fine particles than (A1). As such an apparatus, for example, a high pressure type dispersion mixing apparatus can be mentioned.
As the dispersion mixing device (A2), particles that are present in the aqueous dispersion by the shearing force generated at that time and the impact force due to cavitation by passing the constricted portion at a high speed while maintaining the aqueous dispersion at a high pressure. Those having a mechanism for further finely dispersing the are preferable.
(A2) includes, in addition to the above mechanism, a mechanism in which a mechanism that causes the solution that has passed through the throttle in the mechanism to collide with a substrate such as diamond is added, or two throttles that face the water dispersion What has a mechanism etc. which make it squirt more and make it collide can also be used.

  Examples of the high-pressure dispersion mixer include an ultra-high pressure homogenizer (manufactured by IKA), a microfluidizer (manufactured by Mizuho Kogyo Co., Ltd.), a high-pressure homogenizer (manufactured by Niro Soabi), and a Gaurin homogenizer (manufactured by Gaulin). The

  As the dispersion mixing device (A2), two or more types of devices selected from these high-pressure dispersion mixing devices may be connected in series and used in combination.

The temperature when passing through the dispersion mixing apparatus (A2) is less than the melting temperature of the urethane prepolymer (U), preferably from the melting temperature, from the viewpoint of preventing decomposition or deterioration of the polyurethane resin (U1) as a dispersion. Further, a temperature lower than 5 ° C. and a temperature higher than room temperature, more preferably a temperature lower than the melting temperature by 10 to 120 ° C. and higher than room temperature is preferable from the viewpoint of dispersion efficiency and suppression of decomposition / deterioration.
The polyurethane resin aqueous dispersion (Q1) may be supplied as it is to the dispersion mixing device (A2), but if necessary, water may be further supplied at the same time, and the weight ratio of (Q1) to water is: Although it is appropriately selected depending on the resin component content of the target aqueous dispersion, it is usually (U1) / water = 10/2 to 100, preferably 10/5 to 50.
Moreover, the residence time in the dispersion mixing apparatus of (U1) and water is 0.1 to 30 minutes normally, Preferably it is 1 to 5 minutes.

  When dispersing in the dispersion mixing apparatus (A2), one or more selected from a pH adjuster, an antifoaming agent, an anti-coloring agent, a plasticizer, a release agent and the like are added as necessary. be able to. Moreover, you may concentrate or dilute after dispersion | distribution as needed.

The second dispersion step in the present invention is a step of further finely dispersing the polyurethane resin (U1) having a volume average particle diameter of 0.1 to 100 μm to 1/2 to 1/1000.
When the volume average particle diameter of (U1) is 0.1 to 1 μm, it is preferably finely dispersed to 1/2 to 1/10, and when the volume average particle diameter of (U1) exceeds 1 μm and is 10 μm or less, Preferably 1/5 to 1/100, more preferably 1/10 to 1/100 finely dispersed, and when the volume average particle diameter of (U1) is more than 10 μm and not more than 100 μm, preferably 1/50 to 1 / 1,000, more preferably 1/100 to 1/1000.

  The specific volume average particle diameter of the polyurethane resin aqueous dispersion (Q2) is 0.01 to 5 μm, but from the viewpoint of improving the dispersion stability of (Q2), preferably 0.01 to 4 μm, more preferably. Is 0.02 to 2 μm, more preferably 0.01 to 1 μm, particularly preferably 0.03 to 0.8 μm.

In the method for producing an aqueous polyurethane resin dispersion (Q2) of the present invention, each of the above steps may be performed discontinuously, but at least two of the steps are preferable, and all steps are more preferable. It is a method of performing continuously.
Specifically, following the urethanization reaction, preparation of solid particles having a volume average particle diameter of 0.2 to 20 mm, production of the polyurethane resin water dispersion (Q1), and production of the polyurethane resin water dispersion (Q2) are continued. It is a method to do in. Manufacturing time is shortened by carrying out continuously. In particular, the steps (Q1) to (Q2) are preferably performed continuously from the viewpoint that excellent dispersion stability can be obtained.

  The polyurethane resin aqueous dispersion (Q2) obtained in this way does not substantially use an organic solvent in the production process, and therefore there is substantially no remaining organic solvent.

The solid content concentration (content of components other than water) of the polyurethane resin aqueous dispersion (Q2) obtained by the production method of the present invention is preferably 20 to 65%, more preferably 25 to 55%.
The solid concentration was about 1 g of an aqueous dispersion thinly stretched on a Petri dish, weighed accurately, then weighed the weight after heating at 130 ° C for 45 minutes using a circulating constant temperature dryer, and before weighing, It can be obtained by calculating the ratio (percentage) of the remaining weight after heating to the weight.
The viscosity of the polyurethane resin aqueous dispersion (Q2) obtained by the production method of the present invention is preferably 10 to 100,000 mpa · s, more preferably 10 to 5,000 mpa · s. The viscosity can be measured at a constant temperature of 25 ° C. using a BL type viscometer.
The pH of the polyurethane resin aqueous dispersion (Q2) obtained by the production method of the present invention is preferably 2 to 12, more preferably 4 to 10. The pH can be measured at 25 ° C. with pHMeter M-12 (manufactured by Horiba Seisakusho).

  The polyurethane resin aqueous dispersion (Q2) obtained by the production method of the present invention is usually a polyurethane resin aqueous dispersion satisfying all of the following (1) to (3).

(1) The organic solvent content in the polyurethane resin aqueous dispersion is 0.1% or less.
(2) The volume average particle diameter (Dv) of the polyurethane resin is 0.01 to 5 μm.
(3) The volume average particle diameter / number average particle diameter (Dv / Dn) of the polyurethane resin is 1.2-5.

(1) can be quantified using gas chromatography or the like, and is preferably 0.05% or less, and most preferably there is no remaining organic solvent (below the detection limit; the detection limit is usually 0. 01%).
The Dv of the polyurethane resin (2) is preferably from 0.01 to 4 μm, more preferably from 0.02 to 2 μm, still more preferably from 0.01 to 1 μm, and particularly preferably from the viewpoint of improving dispersion stability. 03 to 0.8 μm.
Dv / Dn of (3) is the above-mentioned laser diffraction particle size distribution measuring device [for example, LA-750 (manufactured by Horiba Seisakusho)] or light scattering particle size distribution measuring device [for example, ELS-8000 (manufactured by Otsuka Electronics Co., Ltd.) ], More preferably 1.2-4, particularly preferably 1.2-3. If Dv / Dn is within this range, the dispersion stability and the film-forming property during drying can be further improved.

  The polyurethane resin aqueous dispersion of the present invention comprises a coating composition, an adhesive composition, a binder composition for fiber processing (a binder composition for pigment printing, a binder composition for nonwoven fabric, a sizing agent composition for reinforcing fibers, an antibacterial agent). Binder compositions for use), coating compositions (waterproof coating compositions, water repellent coating compositions, antifouling coating compositions, etc.), raw materials for artificial leather and synthetic leather, and the like.

  If necessary, the coating composition may contain other additives such as coating auxiliary resins, pigments, pigment dispersants, viscosity modifiers, antifoaming agents, leveling agents, preservatives, anti-degradation agents, stabilizers and antifreezing agents. 1 type (s) or 2 or more types, such as an agent, can be added.

  When used as an antibacterial agent binder composition, coating composition, raw material composition for artificial leather / synthetic leather, additives, concentration of treatment liquid, means for application to fiber, amount attached to fiber, treatment conditions, etc. It can be appropriately selected depending on the application.

<Example>
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these. Hereinafter, “part” means “part by weight” and “%” means “% by weight”.

As described above, the melting temperature is measured in accordance with JIS K7210 (Testing method for melt mass flow rate of plastic-thermoplastic plastic) and using “melt indexer type I” (manufactured by Tester Sangyo Co., Ltd.) The temperature at which the melt mass flow was 10 g / 10 min at 2.16 kg was taken as the melting temperature.

Example 1
To a KRC kneader (manufactured by Kurimoto Seiko Co., Ltd.) of a biaxial kneader, 212.0 parts of a polycarbonate diol “Nippolan 980R” (manufactured by Nippon Polyurethane Co., Ltd.) having a Mn of 2,000, 23 parts of DMPA and 4,4-dicyclohexylmethane 87.4 parts of diisocyanate (hydrogenated MDI) were introduced under a nitrogen atmosphere. Thereafter, the mixture was heated to 200 ° C. and kneaded for 10 minutes to carry out a urethanization reaction. The isocyanate group content of the reaction product was 1.5%. The reaction product was taken out, rolled with a pressure press machine heated to 180 ° C., and then cut with a square pellet machine (manufactured by Horai Co., Ltd.). Subsequently, 17.4 parts of triethylamine (neutralizing agent) was added to 662.6 parts of 90 ° C. ion-exchanged water, and the mixture was adjusted to 16,000 rpm using a TK homomixer (manufactured by Primix Co., Ltd.) at 90 ° C. And then dispersed for 3 minutes at 20,000 rpm using Claremix (manufactured by M Technique Co., Ltd.) under the condition of 90 ° C. to obtain an aqueous polyurethane resin dispersion (Q1-1). Furthermore, under the condition of 90 ° C., the obtained dispersion was passed through a high-pressure homogenizer (manufactured by Niro Soabi) with a pressure of 150 MPa three times to disperse the polyurethane resin aqueous dispersion (Q2-1) 1 1,000 parts were obtained. Table 1 shows the conditions and analysis values in each step. Similarly, the conditions and analytical values in each step are shown in Table 1 for the following examples and comparative examples.
The dispersing devices in Table 1 are (1) TK homomixer (manufactured by PRIMIX Co., Ltd.), (2) CLEARMIX (manufactured by M Technique Co., Ltd.), and (3) high-pressure homogenizer (manufactured by Niro Soavi Corporation). (4) A simple pressure reactor (made by pressure-resistant glass industry), (5) KRC kneader (made by Kurimoto Seiko Co., Ltd.).

Example 2
After urethanization in the same manner as in Example 1, the resin was extruded through pores having a diameter of 2 mm at 200 ° C. to form a string having a diameter of 2 mm, and then cooled to 90 ° C. This was introduced into 684.5 parts of 90 ° C. ion-exchanged water, and then cut into a volume average particle diameter of 2 mm with a rotary blade. 16.1 parts of triethylamine (neutralizing agent) was added thereto, and the mixture was introduced into a TK homomixer and CLEARMIX under the same conditions as in Example 1. By the same treatment as in Example 1, a polyurethane resin aqueous dispersion ( Q2-2) 1,000 parts were obtained.

Example 3
After performing urethanization to triethylamine addition in the same manner as in Example 1, it was dispersed at 15,000 rpm for 10 minutes using a TK homomixer under conditions of 150 ° C. under pressure, and an aqueous polyurethane resin dispersion (Q1-3 ) Further, under a condition of 150 ° C., the obtained dispersion was passed through a high-pressure homogenizer under a pressure of 150 MPa three times to disperse to obtain 1,000 parts of a polyurethane resin aqueous dispersion (Q2-3).

Example 4
After performing urethanization to triethylamine addition in the same manner as in Example 1, it was dispersed for 1 minute at 15,000 rpm using a TK homomixer at 90 ° C. to obtain an aqueous polyurethane resin dispersion (Q1-4). It was. Furthermore, under the condition of 90 ° C., the obtained dispersion was passed through a high-pressure homogenizer (manufactured by Niro Soabi) with a pressure of 100 MPa three times to disperse the polyurethane resin aqueous dispersion (Q2-4) 1 1,000 parts were obtained.

Example 5
In Example 1, 201.2 parts of polycarbonate diol “Nippolan 980R”, 23.2 parts of DMPA, 100.4 parts of 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI), 662.5 parts of ion-exchanged water The same operation as in Example 1 was carried out except that 17.5 parts of triethylamine and 1,000 parts of polyurethane resin aqueous dispersion (Q2-5) were obtained.

Comparative Example 1
In a simple pressure reaction apparatus equipped with a stirrer and a heater, 204 parts of a polycarbonate diol “Nippolan 980R” having an Mn of 2,000, 23.1 parts of DMPA, 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI) 97.1 And 216.6 parts of acetone were charged while introducing nitrogen. Thereafter, the mixture was heated to 85 ° C. and subjected to urethanization reaction for 10 hours to produce a prepolymer. The isocyanate content of the resin solid at the end of the urethanization reaction was 1.5%. After cooling the reaction mixture to 40 ° C., 17.4 parts of triethylamine (neutralizing agent) and 662.6 parts of water were added while stirring in a simple pressure reactor to obtain an aqueous polyurethane resin dispersion. Subsequently, the product was heated at 65 ° C. under reduced pressure for 8 hours to remove acetone, thereby obtaining 1,000 parts of a polyurethane resin aqueous dispersion.
The NCO content of (U) in Comparative Example 1 in Table 1 indicates the isocyanate content of the prepolymer, and the melting temperature of (U) is the melting temperature of the dried product of the obtained polyurethane resin aqueous dispersion. Show.

Comparative Example 2
After urethanization to triethylamine addition in the same manner as in Example 1, the mixture was dispersed at 150 rpm for 5 minutes in a KRC kneader of a twin-screw kneader under the condition of 185 ° C. [(U) melting temperature of 170 ° C. or higher]. 1,000 parts of a polyurethane resin aqueous dispersion was obtained.

Comparative Example 3
After performing urethanization to triethylamine addition in the same manner as in Example 1, the mixture was dispersed for 10 minutes at 15,000 rpm using a TK homomixer at 150 ° C. to obtain 1,000 parts of a polyurethane resin aqueous dispersion. .

Comparative Example 4
In a KRC kneader of a twin-screw kneader, 224.2 parts of a polycarbonate diol “Nippolan 980R” having an Mn of 2,000, 22.9 parts of DMPA, and 73 parts of 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI) were added in a nitrogen atmosphere. Introduced in. Thereafter, the mixture was heated to 200 ° C. and kneaded for 10 minutes to carry out a urethanization reaction. The reaction product was taken out, rolled with a press machine heated to 180 ° C., and then cut with a square pellet machine. Subsequently, after adding 17.2 parts of triethylamine (neutralizing agent) to 662.8 parts of ion-exchanged water at 90 ° C. and dispersing at 16,000 rpm for 3 minutes using a TK homomixer at 90 ° C. A polyurethane resin aqueous dispersion was obtained by dispersing for 3 minutes at 20,000 rpm using CLEARMIX under the condition of 90 ° C. Furthermore, an attempt was made to pass the obtained dispersion through a high-pressure homogenizer under a pressure of 150 MPa under the condition of 90 ° C., but the volume average particle size of the polyurethane resin aqueous dispersion was too large, so the flow path of the high-pressure homogenizer The resin composition was clogged inside. Table 1 shows the physical properties of the polyurethane resin aqueous dispersion before passing through the high-pressure homogenizer. Moreover, about the dry film, the film for evaluation was not able to be created.

Each physical property value of the aqueous dispersion obtained above was measured. The measuring method is shown below.
<Mw / Mn>
The polyurethane resin was added to DMF so that the solid content of the polyurethane resin was 0.0125% by weight, stirred at room temperature for 1 hour, and filtered under pressure with a filter having a pore size of 0.3 μm. The contained urethane resin was measured by GPC using DMF as a solvent and polystyrene as a molecular weight standard.
<Dv / Dn>
The polyurethane resin aqueous dispersion was diluted with ion-exchanged water so that the solid content of the polyurethane resin was 0.01% by weight, and then measured using a light scattering particle size distribution analyzer [ELS-8000 (manufactured by Otsuka Electronics Co., Ltd.)]. did.
<Physical properties of dry film (100% stress, tensile strength, elongation at break)>
5. According to JIS K7311 Based on a tensile test. The measurement sample was 10 parts of a polyurethane resin aqueous dispersion and 1 part of N-methylpyrrolidone uniformly mixed in a 10 cm × 20 cm × 0.1 cm polypropylene mold in such an amount that the film thickness after moisture drying was 200 μm. Based on a film obtained by pouring and heating and drying at room temperature for 12 hours at 105 ° C. for 3 hours at room temperature, the film was prepared based on the test piece 5.1 described in JIS K7311.
<Odor of dispersion>
The solvent odor of the polyurethane resin aqueous dispersion adjusted to 25 ° C. was subjected to sensory evaluation. When the solvent odor is not felt, it is marked as ◯, and when the solvent odor is felt, it is marked as x.
<Stability of dispersion>
The polyurethane resin aqueous dispersion whose temperature was adjusted to 25 ° C. was allowed to stand for 12 hours, and the occurrence of sediment was visually evaluated. The case where no sediment was generated was marked as ◯, and the case where sediment was generated was marked as x.

  The aqueous polyurethane resin dispersion of the present invention can be suitably used as a coating composition, an adhesive composition, and a binder for fiber processing.

Claims (9)

  A solid polyurethane prepolymer (U) obtained without using an organic solvent and having a terminal isocyanate group content exceeding 0.5% by weight is converted into a polyurethane prepolymer (U) by using one or more dispersion mixers (A1). After being dispersed in water at a temperature lower than the melting temperature to obtain a polyurethane resin aqueous dispersion (Q1) comprising a polyurethane resin (U1) having a volume average particle diameter of 0.1 to 100 μm, the dispersion mixing device (A1) ) And a dispersion mixing apparatus (A2) of one or more different dispersion methods, at a temperature lower than the melting temperature of the polyurethane prepolymer (U), the volume average particle diameter of the polyurethane resin (U1) is 1/2 to 1 / A polyurethane resin aqueous dispersion (Q2) comprising a polyurethane resin having a volume average particle diameter of 0.01 to 5 μm, which is dispersed to a volume average particle diameter of 100 Manufacturing method.   The polyurethane resin aqueous dispersion according to claim 1, wherein the polyurethane resin (U) is a particulate material having a melting temperature of 70 to 280 ° C and a volume average particle diameter of 0.2 to 20 mm at 25 ° C. Method.   The method for producing an aqueous polyurethane resin dispersion according to claim 1 or 2, wherein the dispersion mixing device (A1) is at least one selected from a rotary dispersion mixing device and a media type dispersion mixing device.   The method for producing an aqueous polyurethane resin dispersion according to any one of claims 1 to 3, wherein the dispersion mixer (A2) is a high-pressure dispersion mixer.   The polyurethane prepolymer (U) is a polyurethane prepolymer obtained by urethanating a polyol and a polyisocyanate at 150 ° C to 250 ° C in the absence of an organic solvent. A method for producing an aqueous polyurethane resin dispersion.   6. The method for producing an aqueous polyurethane resin dispersion according to claim 5, wherein the urethanization reaction is carried out in a uniaxial or biaxial kneader.   Following the urethanization reaction, preparation of solid particles having a volume average particle diameter of 0.2 to 20 mm, production of the polyurethane resin water dispersion (Q1) and production of the polyurethane resin water dispersion (Q2) are continuously performed. A process for producing an aqueous polyurethane resin dispersion according to claim 5 or 6.   The method for producing an aqueous polyurethane resin dispersion according to any one of claims 1 to 7, wherein the content of the hydrophilic group in the polyurethane prepolymer (U) is 5% or less based on the weight of the polyurethane prepolymer (U). . A polyurethane resin aqueous dispersion obtained by the production method according to claim 1 and satisfying all of the following (1) to (3).
(1) The organic solvent content in the polyurethane resin aqueous dispersion is 0.1% or less.
(2) The volume average particle diameter (Dv) of the polyurethane resin is 0.01 to 5 μm.
(3) The volume average particle diameter / number average particle diameter (Dv / Dn) of the polyurethane resin is 1.2-5.