JP4783553B2 - Method for producing aqueous polyurethane dispersion - Google Patents

Description

The present invention relates to aqueous polyurethane dispersions. More particularly, is not less 1000ppm or less organic solvent content relates to the method of manufacturing the aqueous polyurethane dispersions urea groups contained in the polymer mixture comprising a polymer having a polyurethane and a hydrophilic group is less than 0.3 mmol / g Is.

  Aqueous dispersions are used in the fields of paints, adhesives, binders or coating agents. These aqueous dispersions are becoming increasingly important from the viewpoints of environmental protection, resource saving, safety, and the like. Among these, polyurethane aqueous dispersions are used as highly functional aqueous dispersions because of their excellent durability, chemical resistance, abrasion resistance, and other properties, and are expected to grow in the future.

  As a method for producing these aqueous polyurethane dispersions, a solution method is known in which water is added to a polyurethane solution subjected to chain elongation in an organic solvent to perform phase inversion emulsification, and the organic solvent is removed by distillation. A method for obtaining an aqueous dispersion using an extruder is disclosed. Since these methods use an organic solvent, the process of removing the organic solvent is complicated, and there is a problem in economic efficiency. It is difficult to completely remove the organic solvent from the obtained polyurethane aqueous dispersion. There are environmental pollution problems, safety problems, and odor problems due to solvents. Patent Document 1 only discloses a method for obtaining an aqueous polyester dispersion using an organic solvent.

  Further, a prepolymer mixing method is known in which an isocyanate group-terminated prepolymer having water dispersibility is synthesized, neutralized with an amine or the like, dispersed in water, and chain-extended with a diamine or the like (see Patent Document 2). This prepolymer mixing method has a problem that the water resistance of a film obtained by forming a film of an aqueous dispersion is lowered due to the presence of a urea group derived from a chain extension reaction with diamine or water.

As a method not using an organic solvent, there is known a method in which a polyester containing a polyester and a sulfonate group is melt-kneaded using a twin-screw extruder, and water is added to perform phase inversion into an aqueous dispersion ( (See Patent Document 3). However, even if this method is applied to polyurethane, there is a problem that an aqueous dispersion system that satisfies a good dispersion state and physical properties aimed by the present inventors cannot be obtained.
JP-A-10-139848 JP 2003-138021 A International Publication No. 01/002490 Pamphlet

An object of the present invention is to provide a method for producing an aqueous polyurethane dispersion excellent in a good balance between a good dispersion state and mechanical properties, and having low odor and water resistance.

As a result of intensive studies to solve the above problems, the inventors of the present invention have a heat of fusion of 30 mJ / mg or less measured by differential scanning calorimetry comprising any of the following cases (1) to (3). It has been found that an aqueous dispersion obtained by melt-mixing a polymer mixture with water at 100 ° C. to 260 ° C. in an extruder in the absence of an organic solvent has excellent performance, and has completed the present invention.
(1) Only polyurethanes with hydrophilic groups
(2) Polyurethane having a hydrophilic group and polyurethane having no hydrophilic group
(3) A polymer other than a polyurethane having a hydrophilic group and a polyurethane having no hydrophilic group

  The aqueous polyurethane dispersion of the present invention has an excellent balance between a good dispersion state and mechanical properties. In addition, since the polyurethane aqueous dispersion has an organic solvent content of 1000 ppm or less, it is excellent in low odor and is good from the viewpoint of work environment and environmental pollution. Moreover, since the content (concentration) of urea groups contained in the polymer mixture is 0.3 mmol / g or less in the polyurethane aqueous dispersion, the film obtained from the polyurethane aqueous dispersion has excellent water resistance. Yes. Therefore, the polyurethane aqueous dispersion of the present invention can be suitably used in a wide range of fields such as paints, adhesives, binders or coating agents.

Hereinafter, the aqueous polyurethane dispersion of the present invention and the production method thereof will be described in detail.
In the present invention, it is first important that the urea group contained in the polymer mixture comprising any one of the following (1) to (3) of the aqueous polyurethane dispersion is 0.3 mmol / g or less.
(1) Only polyurethanes with hydrophilic groups
(2) Polyurethane having a hydrophilic group and polyurethane having no hydrophilic group
(3) A polymer other than a polyurethane having a hydrophilic group and a polyurethane not having a hydrophilic group For example, in a dispersion system in which a polyurethane prepolymer is dispersed in water containing an organic solvent and further polymerized with diamine or the like, a urea group is used. This means that the water resistance when the dispersion is made into a film is inferior due to the formation of, so that the critical amount is 0.3 mmol / g or less. Preferably it is 0.15 mmol / g or less, More preferably, it is 0.08 mmol / g or less.

  In the present invention, it is important that the organic solvent content of the aqueous dispersion is 1000 ppm or less. This is because the organic solvent that inevitably remains in the method of removing the solvent from the dispersion of the polyurethane solution dissolved in the organic solvent in water has an adverse effect on the odor and stability of the dispersion, and its limit amount Means 1000 ppm or less. Preferably it is 800 ppm or less, More preferably, it is 500 ppm or less. Particularly preferably, no organic solvent is used at the time of producing the dispersion, and the remaining organic solvent is substantially absent.

Furthermore, what is important in the present invention is to disperse the polymer mixture comprising any of the above cases (1) to (3) in water. In particular, the polymer mixture has a heat of fusion by differential scanning calorimetry of 30 mJ. / Mg or less. This is because, when an aqueous polyurethane dispersion is produced, it is not possible to obtain a good dispersion simply by using thermoplastic polyurethane as a raw material, and the heat of fusion by differential scanning calorimetry of the above polymer mixture containing polyurethane. Means that a good aqueous dispersion can be obtained only when a material having a viscosity of 30 mJ / mg or less is used. Preferably, it is 25 mJ / mg or less, more preferably 20 mJ / mg or less.

In the present invention, the polymer mixture comprises any of the following (1) to (3).
(1) Only polyurethanes with hydrophilic groups
(2) Polyurethane having a hydrophilic group and polyurethane having no hydrophilic group
(3) A polymer other than a polyurethane having a hydrophilic group and a polyurethane having no hydrophilic group

  The concentration of the hydrophilic group in the polymer mixture is preferably 0.05 mmol / g or more. More preferably, it is 0.07 mmol / g or more, Most preferably, it is 0.09 mmol / g or more. In consideration of the water resistance of the particles obtained by removing the dispersion medium from the polyurethane aqueous dispersion or the film obtained by forming a film of the particles, the upper limit is about 2 mmol / g. Preferably it is about 1.5 mmol / g, More preferably, it is about 1 mmol / g. For example, when the sulfonic acid or a salt thereof is a hydrophilic group, it preferably contains a concentration of 0.05 to 2 mmol / g, more preferably 0.05 to 1 mmol, in terms of —SO 3 — group per 1 g of the polymer mixture. / G. Within these ranges, the dispersion stability of the aqueous polyurethane dispersion is good, and the water resistance, heat and humidity resistance of the fine particles, film and film obtained from the aqueous polyurethane dispersion are excellent.

  The ratio of polyurethane to the total amount of polyurethane and polymer is preferably 50% by mass or more, more preferably 60% by mass or more, and most preferably 70% by mass or more. Within these ranges, the dispersion stability of the aqueous polyurethane dispersion is good, and the mechanical properties of the fine particles, film and film obtained from the aqueous polyurethane dispersion are excellent.

  In the present invention, the polymer having a hydrophilic group is a thermoplastic resin and needs to have a hydrophobic skeleton and a hydrophilic group.

  In the present invention, the hydrophilic group means a hydrophilic group or a functional group that can be changed to a hydrophilic group at the time of dispersion, and having a hydrophilic group means a hydrophilic group and / or a hydrophilic group at the time of dispersion. It has a functional group that can be changed.

  The hydrophobic skeleton is not particularly limited as long as it is a thermoplastic resin. Polyurethane, polyester, polyamide, polyvinyl alcohol, polyethylene glycol, polyolefin resin and unsaturated carboxylic acid or its ester are copolymerized or grafted. Etc. Of these, polyurethane, polyester, polyamide and the like are preferable from the viewpoint of compatibility with polyurethane. These may be used alone or in combination of two or more.

  The hydrophilic group is a group having an affinity for water, or a functional group that changes to a hydrophilic group upon contact with water when dispersed in water. Specifically, examples of hydrophilic groups (groups having an affinity for water) include sulfonic acid, carboxylic acid, phosphoric acid, sulfobetaine group, hydroxyl group, and polyoxyethylene group. Examples of the functional group that can be changed to a hydrophilic group at the time of dispersion include salts thereof, hydrolyzable ketimine groups, oxazolidine groups, and latent carboxyl compounds described in JP-A-10-25406. Of these, a hydroxyl group, a polyoxyethylene group, a carboxylic acid, a sulfonic acid, or a salt thereof is preferable. Of these functional groups, sulfonic acid and its salts are particularly preferred.

  In the present invention, the polyurethane may be used if it has a thermoplastic urea group concentration of 0.60 mmol / g or less, and the urea group concentration is preferably 0.30 mmol / g or less, more preferably. It is 0.15 mmol / g or less.

As a method for producing such a polyurethane, a known method can be adopted, and it can be produced by reacting a polyisocyanate, a polyol and a chain extender in the presence or absence of a catalyst. As an example, various methods for producing polyurethane are disclosed in “Polyurethane resin handbook” edited by Keiji Iwata, 1st Nikkan Kogyo Shimbun (1987), and various embodiments can be implemented by referring to these. However, in producing a polyurethane having the above urea group concentration, it is necessary to adjust the concentration of amino groups used in the polyol and / or chain extender. Further, when the molar ratio (NCO / OH) of the isocyanate group and the active hydrogen compound that reacts with the isocyanate group is high, a part of the remaining isocyanate group reacts with moisture or moisture to generate a urea group. Therefore, the concentration of amino groups and / or remaining isocyanate groups used in the production of polyurethane should be 0.60 mmol / g or less, preferably 0.3 mmol / g or less, more preferably 0.15 mmol / g or less. Thus, a polyurethane having a preferable urea group concentration of the present invention can be obtained. Moreover, the urea group density | concentration of a polymer mixture can be 0.3 mmol / g or less by using the polymer which has this polyurethane and a hydrophilic group in the above-mentioned range.

Polyisocyanate, which is one of the components, is shown on pages 71 to 98 of the above-mentioned document, etc., and as a most preferable, specific example used in the present invention, tolylene diisocyanate (including various mixtures of isomers) (TDI), diphenylmethane diisocyanate (including various mixtures of isomers) (hereinafter abbreviated as MDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI) Xylene diisocyanate (XDI), hydrogenated xylene diisocyanate (hydrogenated XDI), and norbornane diisocyanate (NBDI). These can be used individually or in mixture of 2 or more types.

  Also, as the polyol, various active hydrogen compounds are disclosed on pages 99 to 117 of the above-mentioned document, and the polyol suitable for the present invention is mainly composed of an acid component monomer and an alcohol component monomer. Polyester polyols that are condensates, polyester polyols obtained by ring-opening polymerization of cyclic ester compounds such as ε-polycaprolactone, and polyether polyols, and many such as 1,4-butanediol and 1,6-hexanediol. Examples thereof include polycarbonate diols obtained by condensation reaction of monohydric alcohols with dimethyl carbonate, diethyl carbonate and the like, and various specific examples thereof are disclosed. These disclosed polyols can be used alone or in combination of two or more.

Moreover, as a chain extender, "CHEMISTRY AND" written by HENRI ULRICH
TECHNOLOGY OF ISOCYANATES "(John Wiley &
SONS, Inc. ,), Pages 399 to 406 and the like, various chain extenders are disclosed. Of these, dihydric alcohols are preferable, and ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol) NPG), 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4- Pentanediol, 2-ethyl-1,3-hexanediol, 1,3-dihydroxycyclohexane, and 1,4-dihydroxycyclohexane are more preferable. These may be used alone or in admixture of two or more.

  When a polyurethane having a hydrophilic group is used as the polymer having a hydrophilic group, the polyurethane having the hydrophilic group as described above is used. The method for introducing a hydrophilic group into the polyurethane is not particularly limited, but the hydrophilic group is introduced into the polyurethane by using a part or all of the polyol and / or chain extender having a hydrophilic group. A method is mentioned. Examples of the polyol and / or chain extender include polyols such as polyether polyols produced using an active hydrogen compound having a hydrophilic group. As the active hydrogen compound, a compound having one hydrophilic group and two or more active hydrogen groups is preferably used. More specifically, a hydrophilic group such as a sulfonic acid group or a carboxylic acid group is used. An active hydrogen compound having a group.

  For example, active hydrogen compounds having a carboxylic acid group include 2,2-dimethylolacetic acid, 2,2-dimethylollactic acid, 2,2-dimethylolpropionic acid (hereinafter abbreviated as DMPA), 2,2-dimethylol. Dihydroxycarboxylic acids such as butanoic acid (hereinafter abbreviated as DMBA), 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, for example, diaminocarboxylic acids such as lysine and arginine, and their metal salts and ammonium Examples include salts. Preferably, 2,2-dimethylolpropionic acid (DMPA) and 2,2-dimethylolbutanoic acid (DMBA) are used.

  Examples of the active hydrogen compound having a sulfonic acid group include those obtained by a synthesis reaction of an epoxy group-containing compound and an acidic sulfite, and dihydroxybutanesulfonic acid and dihydroxypropanesulfonic acid are preferably used. N, N-bis (2-hydroxyethyl) -2-aminoethanesulfonic acid, N, N-bis (2-hydroxyethyl) -2-aminobutanesulfonic acid, 1,3-phenylenediamine-4,6 -Disulfonic acid, diaminobutanesulfonic acid, diaminopropanesulfonic acid, 3,6-diamino-2-toluenesulfonic acid, 2,4-diamino-5-toluenesulfonic acid, N- (2-aminoethyl) -2-amino Examples include ethanesulfonic acid, N- (2-aminoethyl) -2-aminobutanesulfonic acid, and metal salts and ammonium salts of these sulfonic acids.

  Examples of the active hydrogen compound having a hydroxyl group include N- (2-aminoethyl) ethanolamine.

  These active hydrogen compounds having a hydrophilic group may be used alone or in combination of two or more.

  Furthermore, as a method of introducing a hydrophilic group into polyurethane, a method of introducing a hydrophilic group into polyurethane by using a polyol having a hydrophilic group produced using a monomer having a hydrophilic group can be exemplified.

  Examples of the polyol having a hydrophilic group include polyester polyols obtained by reacting an acid component having a hydrophilic group with a polyol. In the method of introducing the polyester polyol, a sulfonic acid-containing acid component monomer is preferably used as the acid component having a hydrophilic group. For example, 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, 5- ( p-sulfophenoxy) isophthalic acid, 5- (sulfopropoxy) isophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, sulfopropylmalonic acid, sulfosuccinic acid, 2-sulfobenzoic acid, 2,3-sulfobenzoic acid 5-sulfosalicylic acid and methyl esters of these carboxylic acids, and metal salts and ammonium salts of these sulfonic acids are used. Among them, sodium salt of 5-sulfoisophthalic acid or sodium salt of dimethyl 5-sulfoisophthalic acid is used. Preferably used. The polyol to be reacted with these is not particularly limited, and examples thereof include dihydric alcohols exemplified as the chain extender, and polytetramethylene ether glycol and polyester ether polyols obtained therefrom are also used. Can do.

  Furthermore, the polyester polyol which made the polyol which has an acid component and a hydrophilic group react can be illustrated. As the polyol having a hydrophilic group, a sulfonic acid-containing alcohol component monomer is preferably used. For example, in a synthesis reaction of an epoxy group-containing compound exemplified as an active hydrogen compound having a sulfonic acid group with an acidic sulfite. Examples thereof include dihydroxybutanesulfonic acid, dihydroxypropanesulfonic acid, and / or a salt thereof.

  Moreover, the polyester polyol which has a hydrophilic group which carried out ring-opening polymerization of caprolactone etc. to diol which has hydrophilic groups, such as a carboxylic acid group and a sulfonic acid group, is mentioned. Examples of the diol having a hydrophilic group include the above-mentioned dihydroxycarboxylic acids such as 2,2-dimethylolpropionic acid (DMPA), 2,2-dimethylolbutanoic acid (DMBA), and dihydroxysulfonic acids such as dihydroxybutanesulfonic acid. , Dihydroxypropanesulfonic acid, and / or their salts are preferably used.

  There are no particular restrictions on the method for producing polyols using these active hydrogen compounds or monomers, and the above-mentioned document edited by Keiji Iwata “Polyurethane Resin Handbook”, 1st Nikkan Kogyo Shimbun (1987), pages 99-117, etc. Various known methods disclosed in the above can be adopted. A polyurethane having a hydrophilic group can be obtained by reacting the polyol thus obtained with polyisocyanate. It can be set as polyester which has a hydrophilic group by replacing with polyisocyanate and using polycarboxylic acid. A polymer having a hydrophilic group can be produced by such a method.

In the present invention, it is necessary that the heat of fusion of the polymer mixture comprising any of the above cases (1) to (3) is 30 mJ / mg or less by differential scanning calorimetry. As a method of controlling the heat of fusion of the polymer mixture, for example, as a method of controlling the heat of fusion of polyurethane, the sum of the reaction components of polyisocyanate and a chain extender capable of reacting with polyisocyanate is desired to have a mass concentration with respect to the whole polyurethane. The method of adjusting to become a polyurethane showing the amount of heat of fusion, the method of performing a polymerization reaction at a higher temperature, for example, 190 ° C. or higher, even with the same composition, or pre-reacting polyisocyanate and polyol, Examples thereof include a method of reacting with a chain extender. As a polymer having a hydrophilic group, the amount of heat of fusion can be reduced by reducing the crystalline component.

The heat of fusion in the present invention is measured by the following method.
The heat of fusion of the polymer mixture was measured using a differential scanning calorimeter (for example, trade name: SSC5200H disk station and DSC220C, manufactured by Seiko Denshi Kogyo Co., Ltd.). A film-like section is cut out so that the polymer mixture is about 8 mg, and is cut into thin pieces so as to be as close as possible to the aluminum pan. This is collected in an aluminum pan, covered with a cover, and crimped as a sample. Similarly, a sample of alumina is used as a reference. After setting the sample and the reference at a predetermined position in the cell, the sample is cooled to −70 ° C. at a rate of 20 ° C./min under a nitrogen stream at a flow rate of 40 Nml / min, held for 5 minutes, and then 10 ° C. / The DSC curve is measured by raising the temperature to 300 ° C. at a rate of min, and the heat of fusion is determined from the endothermic peak that appears during this time.

  The calculation of the heat of fusion is performed, for example, with an SSC 5200H disk station in accordance with JIS K7122 (plastic transition heat measurement method). The polymer mixture is prepared by mixing, for example, with a lab plast mill (trade name: lab plast mill 4C150-01, manufactured by Toyo Seiki Seisakusho Co., Ltd.) in which the polymer is adjusted to 200 ° C. in advance. And mixing for 5 minutes at a rotational speed of 100 rpm, or using a device capable of melt-kneading such as a twin screw extruder, single screw extruder, kneader between 180-210 ° C., etc. There is a method of performing under conditions, and the polymer mixture taken out is held for 24 hours in a constant temperature and humidity state at a temperature of 23 ° C. and a relative humidity of 50%.

  Hereinafter, the present invention will be described in more detail by showing a dispersion method. The method for producing the aqueous polyurethane dispersion is not particularly limited as long as the polymer mixture composed of the polyurethane and the polymer having a hydrophilic group can be dispersed in water so that the content of the organic solvent in the aqueous dispersion is 1000 ppm or less. However, in order to obtain a dispersion system without using any organic solvent, an extruder is preferred from the viewpoint that the temperature can be raised above the temperature at which the thermoplastic polymer and the polyurethane are plasticized and can be sufficiently mixed mechanically. In particular, a twin-screw extruder capable of performing melt mixing and phase inversion can be preferably used. Furthermore, from the viewpoint of continuously performing melt mixing and phase inversion, an apparatus that is devised to press-fit water into the mixing zone of the extruder with a pump can be preferably used.

  The temperature of the extruder varies depending on the melting temperature of the polymer, but is usually 80 ° C to 300 ° C, preferably 90 ° C to 280 ° C, more preferably 100 ° C to 260 ° C.

Here, the ratio of water to the polymer during dispersion is 0.0% with respect to 1 part by mass of the resin.
1-60 mass parts, Preferably, it is 0.01-50 mass parts, Preferably, it is 0.02-20 mass parts. In addition, at the time of melt mixing, the amount of water used is about 0.02 to 1 part by mass, and after making a polymer mixture dispersed in water, water is further added to obtain an aqueous dispersion system having a desired concentration. Is efficient.

As described above, it is extremely important to use a polymer mixture having a heat of fusion of 30 mJ / mg or less as determined by differential scanning calorimetry, which makes it possible to use an aqueous polyurethane dispersion that has a good balance between a good dispersion state and mechanical properties. Can be obtained.

  Details of the operation are publicly known, and for example, details are disclosed in Patent Document 3 described above. In addition, when using an anionic group as a hydrophilic group, it is preferable from the point of the dispersion stability of a dispersion system to use basic aqueous solution as water. As the basic aqueous solution, water in which a substance acting as a base in water is dissolved may be used. As the base, for example, the substance described in Patent Document 2 described above can be used. The amount of the basic component in the basic aqueous solution is preferably added so that the anionic group forms a salt, and is 0.3 to 3 equivalents, preferably 0.4 to 2.5 equivalents per equivalent of the anionic group. More preferably, it is 0.4 to 2 equivalents.

Further, in the polyurethane aqueous dispersion of the present invention and the method for producing the same, various auxiliary materials that can be usually used in the aqueous dispersion, for example, a dispersant, an emulsifier, a surfactant, a stabilizer, a wetting agent, a thickener, Foaming agent, antifoaming agent, coagulant, gelling agent, anti-settling agent, charge control agent, antistatic agent, anti-aging agent, softener, plasticizer, filler, coloring agent, flavoring agent, anti-tacking agent Further, a release agent or the like may be used in combination.
Moreover, you may contain another polymer in the range which does not impair the effect of this invention.

The particles obtained from the polyurethane aqueous dispersion of the present invention can be obtained by removing the dispersion medium from the dispersion.
Examples of the method for removing the dispersion medium include a method using a spray dryer, a method in which dispersed particles are precipitated by freeze-coagulation, and then the dispersion system is dissolved and the dispersion medium is removed by filtration or centrifugation.
The particles have a number average particle diameter (Dn) in the range of 60 to 700,000 nm, and can have a desired particle diameter according to the dispersion medium removal conditions.

A film obtained from the aqueous polyurethane dispersion of the present invention is obtained by forming a film on the dispersion and / or the particles.
Examples of the coating method for obtaining a film using the dispersion system include dip coating on various substrates, coating using a blade coater, air knife coater, roll coater, spray coater, etc., brush coating, and the like. It is done. When using the said particle | grain, the method using a hot press, powder slush molding etc. are mentioned, for example. As heating conditions for film formation, for example, room temperature drying or heating in the range of 50 to 200 ° C. can be performed. A film can be formed by holding for 5 seconds to 2 hours in these temperature ranges. The film thus obtained exhibits excellent water resistance desired by the present inventors.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified.

The analysis method and physical property measurement method used in the present invention are described below.
<-SO3-concentration (mmol / g)>
0.2 g of polyurethane and a polymer having a hydrophilic group were precisely weighed and diluted 50 times with DMF. This was measured using a polarization optical system energy dispersive X-ray fluorescence analyzer (XEPOS: manufactured by Spectro). The S element concentration was calculated from a calibration curve prepared in advance. The -SO3- concentration was calculated by converting this per 1 g of precisely weighed sample.

<Dispersibility> The obtained aqueous polyurethane dispersion was passed through a 100-mesh wire mesh, where no undispersed resin or the like was observed on the 100-mesh wire mesh, and x when the undispersed material remained.

<Particle size (nm)> Measured using LS-230 manufactured by Beckman Coulter. The volume average particle diameter (Dw), the ratio of the number average particle diameter (Dn), and Dw / Dn were used as an index of the particle diameter distribution.

<Amount of heat of fusion: ΔH (mJ / mg)> The total amount is in Labo Plast Mill (trade name: Labo Plast Mill 4C150-01, manufactured by Toyo Seiki Co., Ltd.) in which a polymer having a polyurethane and a hydrophilic group is adjusted to 200 ° C. in advance. The mixture was charged to 90 g and kneaded for 5 minutes at a rotation speed of 100 rpm. The removed polymer mixture was kept for 24 hours in a constant temperature and humidity state at a temperature of 23 ° C. and a relative humidity of 50%. The heat of fusion of this polymer mixture was measured using a differential scanning calorimeter (trade name: SSC5200H disk station and DSC220C, manufactured by Seiko Denshi Kogyo Co., Ltd.). The produced polymer mixture was cut into thin pieces so as to be about 8 mg, and a film-like section was cut out so as to be as close as possible to the aluminum pan. This was collected in an aluminum pan, covered with a cover, and crimped as a sample. Similarly, a sample obtained by collecting alumina was used as a reference. After setting the sample and the reference at a predetermined position in the cell, the sample is cooled to −70 ° C. at a rate of 20 ° C./min under a nitrogen stream at a flow rate of 40 Nml / min, held for 5 minutes, and then 10 ° C. / The DSC curve was measured by raising the temperature to 300 ° C. at a rate of min, and the heat of fusion was determined from the endothermic peak appearing during this time. The calculation of the heat of fusion was performed by an SSC 5200H disk station in accordance with JIS K7122 (plastic transition heat measurement method).

<Organic solvent content (ppm)> HP6890 type GC, HP5973 type MS detector (hereinafter abbreviated as GC / MS) manufactured by Hewlett-Packard Company was used. The polyurethane aqueous dispersion is diluted with water and directly injected at 1 μL. The column used is UADX-3D-30M-0.15F. The temperature was maintained at 50 ° C. for 5 minutes, heated to 350 ° C. at a temperature increase rate of 10 ° C./min, and held for 10 minutes. The injection temperature is 250 ° C. and the split ratio is 1/20.

<Urea group concentration (mmol / g)> JNM-AL400 manufactured by JEOL Ltd. was used. The aqueous polyurethane dispersion was dried at 80 ° C. for 24 hours to form a film. 15 mg was weighed into a glass tube and 0.6 ml of d6DMSO solvent was added. After sealing, the mixture was heated at 70 ° C. for 3 hours, and the dissolved one was transferred to an NMR tube for measurement. Using the isocyanate-derived peak as a reference peak, the urea group concentration was calculated from the area ratio of the urea bond-derived peak.

<Film Odor> After coating with a bar coater on a glass plate degreased with acetone in advance so as to have a film thickness of 100 μm, the film odor when dried at 110 ° C. for 5 minutes was subjected to sensory evaluation. The film odor levels were: ○ / no odor, Δ / slight odor, and x / odor.

<Water immersion evaluation> After coating using a bar coater on a glass plate degreased with acetone in advance so as to have a film thickness of 100 μm, it was dried at 110 ° C. for 1 hour. The obtained film was cured at 25 ° C. for 1 day and then immersed in water at 25 ° C. to evaluate the change in appearance. The results of water immersion evaluation were as follows: ○ / no whitening, Δ / slightly whitening, x / whitening.

<Synthesis of polyester polyol>
Synthesis of sulfonic acid group-containing polyester polyol (SSPEs-1) 980 parts of 5-sulfoisophthalic acid dimethyl sodium salt (SSIPA) in a flask equipped with a packed tower, a thermometer, a nitrogen gas inlet tube and a stirrer, 1,6-hexane 1970 parts of diol, 600 parts of neopentyl glycol, 0.2 parts of dibutyltin oxide are added, and the temperature in the flask is maintained at 190 to 200 ° C. so that the top temperature is 70 ° C. or less, until methanol is not distilled off. The transesterification reaction was performed for 7 hours. Furthermore, 1940 parts of adipic acid was added, and the esterification reaction was carried out at a flask internal temperature of 190 to 200 ° C. so that the tower top temperature was 105 ° C. or lower. When the acid value reached 10 mgKOH / g, 0.3 part of tin octylate was added, and the reaction was continued until the acid value reached 1 mgKOH / g at 200 ° C. in the flask. The obtained polyester polyol had a hydroxyl value of 98 mgKOH / g and an acid value of 0.5 mgKOH / g.

Synthesis of sulfonic acid group-containing polyester (SSPEs-2) 620 parts of SSIPA, 2410 parts of diethylene glycol, 0.2 parts of dibutyltin oxide were charged into a flask equipped with a packed tower, a thermometer, a nitrogen gas introduction tube, and a stirring device. The temperature in the flask was maintained at 190 to 200 ° C. so that the column top temperature was 70 ° C. or less, and a transesterification reaction was performed for 7 hours until methanol was not distilled off. Furthermore, 2470 parts of terephthalic acid was added, and the esterification reaction was performed at a flask internal temperature of 190 to 200 ° C. so that the tower top temperature was 105 ° C. or lower. When the acid value reached 10 mgKOH / g, 0.3 part of tin octylate was added. Further, the reaction was performed at an internal temperature of 250 ° C. and a degree of vacuum of 1 mmHg (133 Pa) for 2 hours. The number average molecular weight of the polyester as measured by GPC (gel permeation chromatography) was 17,000.

<Synthesis of polyurethane>
Synthesis of Polyurethane-1 3730 parts of SSPEs-1 were temperature adjusted to 100 ° C. 150 parts of 1,4-BD (1,4-butanediol) adjusted to 60 ° C. are stirred and mixed. To this, 1220 parts of MDI are added and immediately stirred and mixed for 1 minute, at 120 ° C. for 24 hours. Reacted. Furthermore, polyurethane-1 was obtained by cut | disconnecting and grind | pulverizing the hardened | cured material obtained by leaving still for one week in a constant temperature and humidity chamber of 23 degreeC and 55% of relative humidity. The composition is shown in Table 1.

Synthesis of polyurethane-2 Polytetramethylene ether glycol (trade name: PTG-1000, manufactured by Hodogaya Chemical Co., Ltd.) having a hydroxyl value of 112 mgKOH / g is 3010 parts, 350 parts 1,4-BD, 1730 parts Polyurethane-2 having the composition shown in Table 1 was obtained in the same manner as polyurethane-1 except that MDI was used.

Synthesis of polyurethane-3 Polyester polyol having a hydroxyl value of 56 mgKOH / g (trade name: U-2720, manufactured by Mitsui Takeda Chemical Co., Ltd.) 3290 parts, 370 parts of 1,4-BD, 1440 parts of MDI were used. Except for the above, polyurethane-3 having the composition shown in Table 1 was obtained in the same manner as polyurethane-1.

Synthesis of Polyurethane-4 Polycaprolactone diol (trade name: Plaxel 210, manufactured by Daicel Chemical Industries, Ltd.) having a hydroxyl value of 112 mgKOH / g and 1,4-bis (2-hydroxyethoxy) benzene (trade name: BHEB) Polyurethane-4 having the composition shown in Table 1 was obtained in the same manner as Polyurethane-1 except that the temperature of 1430 parts of the mixture of Sun Techno Chemical Co., Ltd. was adjusted at 120 ° C.

<< Synthesis of aqueous polyurethane dispersion >>

Polyurethane-1 is fed at a speed of 100 parts / hour to a co-rotating twin screw extruder (Ikegai Iron Works, PCM-30, L / D = 41.5), set temperature 200 ° C., screw rotation speed 180
While melt-kneading at rpm, ion-exchanged water was continuously supplied at a rate of 80 parts / hour from a supply port provided in an intermediate part of the extruder. The extruded mixture such as resin was cooled to 90 ° C. and discharged by passing it through a single-screw extruder (manufactured by Ikekai Tekko Co., Ltd., FS-40, L / D = 25) installed in the extruder port. The solid content concentration calculated from the weight difference before and after drying was 55%. When this aqueous dispersion was added to warm water (ion-exchanged water heated to 70 ° C.), it was finely dispersed to obtain an aqueous dispersion. Ion exchange water was added to adjust the solid content concentration to 30%, followed by filtration with a 100-mesh wire mesh. No undispersed material was observed, and the dispersion state was good. This polyurethane aqueous dispersion had a volume average particle size (Dw) of 70 nm, a number average particle size (Dn) of 60 nm, and Dw / Dn as an index of particle size distribution of 1.2. This was coated on a glass plate degreased with acetone in advance using a bar coater to a film thickness of 100 μm, and then dried at 110 ° C. for 1 hour. The film was taken out at 110 ° C. for 5 minutes and subjected to sensory evaluation of the film odor, but no odor was felt. The obtained film was cured at 25 ° C. for 1 day and then immersed in water at 25 ° C. to confirm a change in appearance. No change in appearance was observed at all after 1 day and 5 days, and it was confirmed that the film was excellent in water resistance. The composition is shown in Table 2, and the evaluation results are shown in Table 3.

  A polyurethane aqueous dispersion-2 was obtained in the same manner as in Example 1, except that 70 parts / hour of polyurethane-2 and 30 parts / hour of polyester were fed and water from the supply port was 27 parts / hour. , Evaluated in the same way. The composition is shown in Table 2, and the evaluation results are shown in Table 3.

  Polyurethane aqueous dispersion-3 in the same manner as in Example 1 except that polyurethane-3 was fed at 60 parts / hour, SSPEs-2 was fed at 40 parts / hour, and water from the supply port was 25 parts / hour. And evaluated similarly. The composition is shown in Table 2, and the evaluation results are shown in Table 3.

  A polyurethane aqueous dispersion-4 was prepared in the same manner as in Example 1 except that 35 parts / hour of polyurethane-1 and 65 parts / hour of polyurethane-3 were fed and water from the supply port was 25 parts / hour. And evaluated similarly. The composition is shown in Table 2, and the evaluation results are shown in Table 3.

[Comparative Example 1]
The polyurethane-4 was fed at 70 parts / hour, the SSPEs-2 was fed at 30 parts / hour, and the water from the supply port was 25 parts / hour, and the water was made in the same manner as in Example 1. The discharged product did not disperse even when added to warm water, and most of the resin remained on the 100-mesh wire mesh and could not be filtered. The composition is shown in Table 2.

[Comparative Example 2]
A flask equipped with a thermometer, a nitrogen inlet tube, a condenser tube, and a stirrer was charged with 97 parts of MDI, 127 parts of SSPEs-1, 126 parts of U-5610W, and 350 parts of acetonitrile at 70 ° C. for 10 hours. Reacted. When the NCO% of the obtained urethane prepolymer solution became 1.5%, it was cooled to 30 ° C. While stirring 150 parts of this urethane prepolymer solution, 190 parts of ion-exchanged water was added. Further, 2.0 g of 1,4-butanediamine dissolved in acetonitrile solution was gradually added while paying attention to heat generation, and the remaining acetonitrile was distilled off under reduced pressure at 50 ° C. A polyurethane aqueous dispersion-4 having an average particle diameter of 100 nm, a number average particle diameter of 70 nm, and Dw / Dn of 1.44 was obtained. The SO3Na group concentration of the resin was 0.25 mmol / g, and the residual organic solvent concentration by GC / MS of the dispersion was 900 ppm. This was coated on a glass plate degreased with acetone in advance using a bar coater to a thickness of 100 μm, and then dried at 110 ° C. for 1 hour. The film was taken out at 110 ° C. for 5 minutes and subjected to sensory evaluation of the film odor. As a result, a film odor that was considered to be derived from the contained organic solvent was confirmed. The obtained film was cured at 25 ° C. for 1 day and then immersed in water at 25 ° C. to confirm a change in appearance. Slight whitening was observed after 1 day, and whitening was observed after 5 days. The evaluation results are shown in Table 3.

[Comparative Example 3]
In a flask equipped with a thermometer, a nitrogen inlet tube, a condenser tube, and a stirrer, 175 parts of hydrogenated xylylene diisocyanate (trade name: Takenate 600, manufactured by Mitsui Takeda Chemical Co., Ltd.) with a hydroxyl value of 56.1 mgKOH / g 226 parts of polycarbonate diol (trade name: Plaxel CD220, manufactured by Daicel Chemical Industries, Ltd.), 24 parts of neopentyl glycol, 30 parts of DMPA and 195 parts of acetone were charged and reacted at 70 ° C. for 10 hours. When the NCO% of this urethane prepolymer solution reached 4.3%, the solution was cooled to 50 ° C., and 19 parts of triethylamine (TEA) was added. The mixture was further stirred for 30 minutes and cooled to 30 ° C. While stirring 800 parts of water, 574 parts of the obtained urethane prepolymer solution was slowly added, and further 13.9 parts of ethylenediamine was gradually added while paying attention to heat generation. The residual acetone was distilled off under reduced pressure at 50 ° C. to obtain a polyurethane aqueous dispersion-5 having a solid content of 34%, a volume average particle diameter of 90 nm, a number average particle diameter of 70 nm, and Dw / Dn of 1.29. The residual organic solvent concentration of this resin by GC / MS was 5000 ppm. This was coated on a glass plate degreased with acetone in advance using a bar coater to a thickness of 100 μm, and then dried at 110 ° C. for 1 hour. The film was taken out at 110 ° C. for 5 minutes and subjected to sensory evaluation of the film odor. As a result, a film odor that was considered to be derived from the contained organic solvent was confirmed. The obtained film was cured at 25 ° C. for 1 day and then immersed in water at 25 ° C. to confirm a change in appearance. The film was already whitened after one day. The evaluation results are shown in Table 3.

[Comparative Example 4]
To the polyurethane aqueous dispersion-1 shown in Example 1, acetonitrile was added as an organic solvent so as to be 2000 ppm. It was cured at room temperature for 1 day to obtain an aqueous polyurethane dispersion-6. This was coated on a glass plate degreased with acetone in advance using a bar coater to a thickness of 100 μm, and then dried at 110 ° C. for 1 hour. The film was taken out at 110 ° C. for 5 minutes and subjected to sensory evaluation of the film odor. As a result, a film odor that was considered to be derived from the contained organic solvent was confirmed. The obtained film was cured at 25 ° C. for 1 day and then immersed in water at 25 ° C. to confirm a change in appearance. No whitening phenomenon was observed on the film. The evaluation results are shown in Table 3.

Claims (1)

A polymer mixture having a heat of fusion of 30 mJ / mg or less measured by differential scanning calorimetry consisting of any of the following cases (1) to (3) is heated to 100 ° C. in an extruder in the absence of an organic solvent. A process for producing an aqueous polyurethane dispersion characterized by obtaining an aqueous dispersion by melting and mixing with water at 260 ° C.
(1) Only polyurethanes with hydrophilic groups
(2) Polyurethane having a hydrophilic group and polyurethane having no hydrophilic group
(3) A polymer other than a polyurethane having a hydrophilic group and a polyurethane having no hydrophilic group