JP2007277497A - Polyester resin water dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stable water dispersion of a crystalline polyester resin compatible with water resistance of the resultant film and favorable mechanical physical properties. <P>SOLUTION: The water dispersion of a crystalline polyester resin has particle sizes of 30-250 nm, a melting point of 80°C or over and an ionic group concentration of 5-30 mg KOH/g. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an aqueous polyester resin dispersion. More specifically, the present invention relates to an aqueous dispersion of a crystalline polyester resin that can easily form a film excellent in water resistance and scratch resistance and has excellent storage stability.

  Until now, organic solvents have been used in large quantities in the fields of paints, inks, coating agents, adhesives, and various treatment agents such as textile products and paper. Recently, environmental pollution caused by these organic solvents, deterioration of the working environment, etc. As a result, organic solvent emission regulations have been strengthened year by year, both domestically and internationally. In response to such a trend, as a measure for reducing the use of organic solvents, there is an increasing trend of making water-based in many applications.

  As a method for already dispersing or solubilizing the polyester resin in water, a method in which a hydrophilic raw material is copolymerized and introduced into the molecular skeleton, for example, a raw material containing a sulfonic acid metal base, a polyalkylene glycol or an aliphatic carboxylic acid is used. A method of copolymerizing alone or in combination is known. However, in any method, in order to satisfy the solubility or dispersibility in water, it is necessary to use a large amount of the above-mentioned hydrophilic raw material, which may cause problems in terms of water resistance and strength of the obtained film. .

  For example, in Patent Document 1, in order to sufficiently disperse in water, it is necessary to use 8 mol% or more of sulfonic acid metal base compound with respect to the total acid component and 20 mol% or more of polyethylene glycol with respect to the total glycol component. It is described. However, this polyester resin has poor water resistance. That is, being sufficiently dispersible in water means that the water resistance of the film formed after drying is inferior. In this case, when the film comes into contact with water, not only the adhesive strength is lowered, but also the scratch resistance of the product is lowered, so that it is hardly practical. Thus, unless the problem of satisfying the contradictory performances of hydrophilicity and water resistance is overcome, it will not be practical.

  Patent Document 2 proposes an aqueous dispersion of crystalline polyester resin. However, the polyester resin exemplified here is a combination of an aliphatic dicarboxylic acid and an aliphatic diol, and the use of an aliphatic dicarboxylic acid that is already well known reduces the mechanical properties of the polyester resin. However, it is difficult to say that the strength of the obtained film is at a level that can withstand practical use.

  Furthermore, Patent Document 3 proposes a polyester resin aqueous dispersion having a relatively high molecular weight and an aromatic component copolymerized. The particle size of the aqueous dispersion exemplified here as an example is on the order of μm. However, it is not practical from the viewpoint of dispersion stability and film-forming property.

  In addition, as shown in Patent Document 4, when an ionic group such as a sulfonic acid metal base is copolymerized with a polyester resin, even if the introduction amount is minimized as much as possible in consideration of water resistance, After the film formation, the hydrophilic group remains in the molecular chain as it is. Therefore, as described above, moisture can be adsorbed again after drying and film formation, resulting in a decrease in the water resistance of the film.

Japanese Examined Patent Publication No. 47-40873 JP 2004-51806 A JP 2003-226756 A JP-A-7-188423

  The present invention has been made in order to solve the above-mentioned problems of the prior art. Specifically, the dispersion stability of the water dispersion, the water resistance of the resulting film, and good mechanical properties are compatible. An aqueous dispersion of a crystalline polyester resin that can be used is provided. Another objective is to use a crystalline polyester resin having excellent water resistance and scratch resistance, and an aqueous dispersion that is dispersed in an aqueous medium on the order of nm, which has excellent storage stability and can easily form a film. Is to create.

  That is, in the present invention, a crystalline polyester resin having a melting point of 80 ° C. or higher and an ionic group concentration of 5 to 30 mg KOH / g is dispersed, and the particle diameter of the dispersed polyester resin is in the range of 30 to 250 nm. The present invention relates to an aqueous polyester resin dispersion.

  By using a crystalline polyester resin having excellent water resistance and scratch resistance, the crystalline polyester resin can achieve both the dispersion stability of the aqueous dispersion, the water resistance of the resulting film, and good mechanical properties. An aqueous dispersion can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail. In the production of the polyester resin used in the present invention, a monomer containing a carboxylic acid component composed of a divalent or higher polyvalent carboxylic acid compound and an alcohol component composed of a divalent or higher polyhydric alcohol compound is used. .

  When the total amount of carboxylic acid components is 100 mol%, the copolymerization amount of terephthalic acid is 40 mol% or more, preferably 45 mol% or more, more preferably 50 mol% or more, and further preferably 55 mol. %. In the case of 40 mol% or less, the mechanical strength of the obtained coating film becomes low and may not be practical. In addition, other components can be copolymerized to such an extent that the crystallinity of the obtained polyester resin is not impaired. For example, aromatic carboxylic acids such as isophthalic acid, orthophthalic acid and naphthalenedicarboxylic acid, aromatic oxycarboxylic acids such as p-oxybenzoic acid and p- (hydroxyethoxy) benzoic acid, succinic acid, adipic acid, azelaic acid and sebacic acid , Aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, hexahydrophthalic acid, tetrahydrophthalic acid and other unsaturated alicyclics, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid Examples thereof include alicyclic dicarboxylic acids such as acid and 1,4-cyclohexanedicarboxylic acid. Further, if necessary, trimellitic acid, trimesic acid, pyromellitic acid, and other tri- and tetracarboxylic acids and anhydrides thereof may be included. Among these, it is most preferable to use adipic acid in combination with terephthalic acid, considering the production and dispersion stability of the crystalline polyester resin aqueous dispersion and the mechanical properties of the resulting film.

  As the glycol component, when the total amount of glycol components is 100 mol%, the copolymerization amount of 1,4-butanediol is 30 mol% or more and 95 mol% or less, preferably 35 mol% or more and 90 mol%. % Or less, more preferably 40 mol% or more and 85 mol% or less, still more preferably 45 mol% or more and 80 mol% or less. If it is less than 30 mol%, the crystallization rate is slow, and blocking immediately after film formation of a film made of an aqueous dispersion may be severe, resulting in poor coating suitability. On the other hand, if it is 95% or more, the crystallinity of the resin becomes too high, and the storage stability of the aqueous dispersion may deteriorate.

  Further, it is preferable that polytetramethylene glycol is contained as a glycol component, and the copolymerization amount is preferably 10 mol% or less, more preferably 8 mol% or less, more preferably 5% or less, and most preferably 3% or less. is there. When polytetramethylene glycol is not included, the crystallization rate is slow, and blocking immediately after film formation of a film made of an aqueous dispersion may be severe, resulting in poor coating suitability. However, if it exceeds 10 mol%, the glass transition temperature of the resin becomes too low, the mechanical properties may be deteriorated, and the water resistance may be deteriorated.

  Moreover, it is preferable that a glycol component consists of 3 or more components including 1, 4- butanediol. When a highly crystalline component such as terephthalic acid is used as the acid component, for example, because the crystallinity of the segment composed of terephthalic acid and 1,4-butanediol is extremely high, the water dispersibility is poor and even after dispersion. Aggregation is likely to occur and storage stability tends to deteriorate. In order to improve dispersibility and storage stability, it is necessary to moderately reduce the crystallinity of the entire polyester resin, and it is effective to use three or more alcohol components. Examples of glycols that can be used include ethylene glycol, propylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and diethylene glycol. , Triethylene glycol, dipropylene glycol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. Can be mentioned. In addition, ethylene oxide adduct and propylene oxide adduct of bisphenol A, ethylene oxide adduct and propylene oxide adduct of hydrogenated bisphenol A, and the like can also be used. In addition to these, a small amount of triol such as trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, and tetraol may be contained if necessary. Of these, ethylene glycol and 1,4-cyclohexanedimethanol are preferably used.

  In the present invention, it is necessary to use a polyester resin having crystallinity, but terephthalic acid, adipic acid, succinic acid, ethylene glycol, 1,4-butanediol, 1,4-cyclohexane which are preferably used practically as a crystalline component. Polyester resins having a high copolymerization ratio such as dimethanol usually have poor solubility and are often difficult to disperse in water. When the copolymerization ratio of the crystalline component exceeds about 70% by mass with respect to the whole resin, even if an attempt is made to produce an aqueous polyester resin dispersion in the production method described later, the solubility in a single solvent is reduced. Even if a large amount of solvent is used, it may be difficult to obtain a good aqueous dispersion. However, in the present invention, by using three or more glycol components, a good aqueous dispersion can be obtained even in such a hardly soluble resin composition.

  The polyester resin used in the present invention is preferably crystalline. If the polyester resin is crystalline, the performance excellent in scratch resistance can be exhibited. The crystallinity referred to in the present invention means that the temperature is raised from −100 ° C. to 300 ° C. at 20 ° C./min using a differential scanning calorimeter (DSC), and then the temperature is lowered to −100 ° C. at 50 ° C./min. Then, it indicates a melting peak in either of the two temperature raising processes in which the temperature is raised from −100 ° C. to 300 ° C. at 20 ° C./min.

The composition and composition ratio of the polyester resin used in the present invention can be determined by calculation from the integral ratio of ¹ H-NMR measured by dissolving the polyester resin in a solvent such as chloroform D.

  The crystalline melting point of the polyester resin used in the present invention is preferably 80 ° C. or higher. More preferably, it is 90 degreeC or more, More preferably, it is 100 degreeC or more. When the crystalline melting point of the polyester resin is 80 ° C. or lower, the solubility in a solvent becomes very good and an aqueous dispersion can be easily prepared, but the blocking resistance of the resin film may be lowered, It is hard to say that it is practical.

  As a method for producing the polyester resin, a known method can be used. For example, the dicarboxylic acid (or esterified product thereof) and the glycol component are esterified (transesterified) at 150 to 250 ° C., and then the pressure is reduced. However, the method of performing a polycondensation reaction at 230-300 degreeC is mentioned. In addition, you may add a hindered phenol or a hindered amine type compound as a heat stabilizer.

  Since the polyester resin used in the present invention is dispersed in water, it is preferable to introduce a hydrophilic ionic group into the resin. Examples of the ionic group include a sulfonate group, a carboxylate group, and a phosphate group, but a sulfonate group and a carboxylate group are more preferable. When considering water resistance after drying and film formation, a carboxylate group is preferable. Is most preferred. In addition, these ionic groups may be used alone or in combination as required.

  A method for introducing a carboxyl group into a polyester resin is that after polymerizing the polyester resin, trimellitic anhydride, phthalic anhydride, pyromellitic anhydride, succinic anhydride, maleic anhydride, anhydrous 1, 8-Naphthalic acid, 1,2-cyclohexanedicarboxylic anhydride, cyclohexane-1,2,3,4-tetracarboxylic acid-3,4-anhydride, ethylene glycol bisanhydro trimellitate, 5- (2,5 -Dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, naphthalene-1,8: 4,5-tetracarboxylic dianhydride, etc. Add these selected anhydrides, add them, add these acid anhydrides to the oligomer before polycondensation of the polyester, By high molecular weight by polycondensation reaction pressure, there is a method of introducing a carboxyl group into the polyester resin. In this case, the former method is preferable because the target acid value is easily obtained. The carboxyl group thus introduced can be converted to a carboxylate by neutralizing with an amine or an alkali compound as described later.

  Examples of hydrophilic groups other than the carboxylate group include sulfonate groups, and examples of the introduction method include 5-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and 5 [4-sulfophenoxy] isophthalic acid. A dicarboxylic acid or glycol containing a sulfonate group such as a metal salt such as 2-sulfo-1,4-butanediol, or a metal salt such as 2,5-dimethyl-3-sulfo-2,5-hexanediol. The method of copolymerizing is mentioned.

  The polyester resin used in the present invention preferably has an ionic group concentration of 5 to 30 mgKOH / g in order to satisfy both water dispersibility and water resistance. More preferably, it is 6-25 mgKOH / g, Most preferably, it is 7-20 mgKOH / g. When the ionic group concentration is less than 5 mgKOH / g, sufficient dispersion stability may not be ensured, and when it exceeds 30 mgKOH / g, not only the water resistance and mechanical strength of the film are lowered, but also the molecular chain Hydrolysis may be accelerated.

  The polyester resin used in the present invention preferably has a concentration of ionic groups derived from sulfonic acid groups of ionic groups of 6 mgKOH / g or less. More preferably, it is 2 mgKOH / g or less, Most preferably, it is 1 mgKOH / g or less. When the functional group concentration derived from sulfonic acid is 6 mgKOH / g or more, the water resistance of the film is lowered.

  Although the method of manufacturing the polyester resin aqueous dispersion of this invention is not specifically limited, For example, the following method is mentioned. That is, an organic solvent (referred to as A) in which the polyester resin can be dissolved or swollen and an organic solvent (referred to as B) that becomes a poor solvent in which the polyester resin does not dissolve or swell as necessary are used. By using these solvents having different solubilities with respect to the polyester resin, the phase transition from the solvent system to the aqueous system of the polyester resin can be smoothly performed without agglomeration. Moreover, it becomes possible to control the resin particle diameter in the obtained water dispersion by controlling the amount. This is achieved by maintaining the balance of seemingly contradictory effects of promoting the aggregation of molecular chains by B while untangling the polyester molecular chains by A. This makes it possible not only to create a polyester resin aqueous dispersion having a particle size according to the application, but also to have a dispersion having an optimal particle size that can maintain good dispersion stability depending on the polyester resin used. The body can be obtained.

  The temperature during dissolution of the polyester resin is preferably 40 to 160 ° C, more preferably 50 to 140 ° C, further preferably 60 to 120 ° C, and most preferably 70 to 100 ° C. If the temperature is lower than 40 ° C., the crystalline polyester resin may be insufficiently dissolved or swollen, so that the entanglement between the molecular chains cannot be sufficiently solved. If the temperature exceeds 160 ° C., the polyester resin is deteriorated. This is because fear increases.

  Examples of the organic solvent in which the polyester resin can be dissolved or swelled by heating in a temperature range of 40 to 160 ° C. include methyl ethyl ketone, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, 1,3- Examples include dioxane, 1,3-dioxolane, 1,2-hexanediol, methyl cellosolve, butyl cellosolve, ethyl carbitol butyl carbitol, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and triethylene glycol monobutyl ether. Of these, methyl ethyl ketone, butyl cellosolve, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and the like are preferable.

  Examples of the organic solvent that is a poor solvent in which the polyester resin does not dissolve or swell include methanol, ethanol, 1-propanol, isopropyl alcohol, and hexane. Of these, ethanol and isopropyl alcohol are particularly preferable. Here, it is preferable to use the organic solvent which becomes a poor solvent in the range of 0 to 70% by mass ratio with respect to the organic solvent in which the polyester resin can be dissolved or swollen. More preferably, it is 5 to 50%. If a poor solvent exceeding 70% is used, the resin may aggregate and settle.

  When preparing an aqueous dispersion of a polyester resin into which carboxyl groups have been introduced, in order to stabilize the dispersed resin particles, polar groups such as carboxyl groups on the surface of the particles are partly or entirely covered with a basic substance. To sum up.

  As basic substances that can be used for neutralization, amines typified by ammonia and triethylamine, or inorganic bases typified by sodium hydroxide and potassium hydroxide can be used. The use of a volatile amine compound is preferred in order to eliminate the concern of remaining in the film and the resulting decrease in water resistance.

  Only typical examples of volatile amines include ammonia, monomethylamine, dimethylamine, trimethylamine, monoethylamine, mono-n-propylamine, dimethyl-n-propylamine, monoethanolamine, Diethanolamine or triethanolamine, N-methylethanolamine, N-aminoethylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, N, N-dimethylethanolamine, or N, N -Various amines such as dimethylpropanolamine. Particularly preferred are ammonia, triethylamine and the like.

  Moreover, the combined use of two or more selected from these organic basic compounds is not impeded.

  The polyester resin solution thus obtained is phase-transformed into an aqueous system by adding water and stirring. It is preferable to add water little by little while maintaining the temperature of the solution in order to produce a stable aqueous dispersion.

  The organic solvent used in the production of the polyester resin aqueous dispersion of the present invention can be removed as necessary after the aqueous dispersion is obtained. However, in that case, it is preferable to select an organic solvent having a boiling point of less than 100 ° C. among the aforementioned organic solvents. The aqueous dispersion referred to in the present invention may contain a small amount of an organic solvent.

  The particle diameter of the polyester resin aqueous dispersion according to the present invention is very important because it greatly affects the appearance and storage stability of the coating film, and is preferably 30 to 250 nm. More preferably, it is 50-200 nm, Most preferably, it is 100-150 nm. When the particle diameter exceeds 250 nm, not only the dispersion stability is greatly lowered, but also the film forming property is lowered, so that the appearance of the resulting film is deteriorated. On the other hand, if the thickness is less than 30 nm, the film-forming property tends to be remarkably improved. Therefore, fusion and aggregation between the dispersed particles are likely to occur, and as a result, the possibility of causing thickening and poor dispersion is increased. Absent.

  The polyester resin aqueous dispersion of the present invention is preferably prepared at a resin solid content concentration of 5 to 45% by mass. More preferably, it is 10-40 mass%, More preferably, it is 15-35 mass%, Most preferably, it is the range of 20-32 mass%. When the resin solid content concentration exceeds 45% by mass, the solution viscosity becomes high and aggregation between the resin particles tends to occur, so that the dispersion stability is greatly lowered. Moreover, if it is less than 5 mass%, it is hard to say that it is practical from both a manufacturing surface and a use surface.

  In the aqueous dispersion of the present invention, coarse particles of 1 μ or more are 1% or less, preferably 0.5% or less, more preferably 0.2% or less, and still more preferably 0.01% or less in the total polyester resin. It is. If the content exceeds 1%, a precipitate is generated with time, resulting in poor storage stability, and may cause uneven stripes when used as a coating agent.

  As a method of using the aqueous dispersion of the present invention, a plurality of polyester resins and other film-forming resins may be included as necessary. Although it does not specifically limit as such a thing, An acrylic resin, a polyester resin, an alkyd resin, an epoxy resin, a urethane resin, etc. can be utilized.

  The aqueous dispersion of the present invention can contain a curing agent. As the curing agent, commonly used ones can be used, such as melamine compounds, block isocyanates, water-dispersed isocyanate curing agents, epoxy compounds, aziridine compounds, carbodiimide compounds, Examples include oxazoline compounds and metal ions. Melamine-based compound resins and / or blocked isocyanates are generally used from the viewpoints of various performances and costs of the obtained coating films.

  The melamine-based curing agent as the curing agent is not particularly limited, and may be either water-soluble or water-insoluble. For example, alkyl etherified melamine resin is preferable, and methoxy group and A melamine resin substituted with a butoxy group is more preferred. As such a melamine resin, those having a methoxy group alone, Sumimar M-30W, Sumimar M-40W, Sumimar M-50W, Sumimar MC-1 (all manufactured by Sumitomo Chemical Co., Ltd.), Cymel 325, Cymel 327 , Cymel 370, My Coat 723; Cymel 202, Cymel 204, Cymel 232, Cymel 235, Cymel 236, Cymel 238, Cymel 254, Cymel 266, Cymel 267 (both having methoxy and butoxy groups) Product name, manufactured by Mitsui Cytec Co., Ltd.); Mycoat 506 (trade name, manufactured by Mitsui Cytec Co., Ltd.), Uban 20N60, Uban 20SE (both trade names, manufactured by Mitsui Chemicals Co., Ltd.), Super Bekka Min (Dai Nippon Ink Chemical) Gosha, Ltd.), and the like. These may be used alone or in combination of two or more. Among these, Sumimar M-40W and Sumimar MC-1 are more preferable.

  The blocked isocyanate can be obtained by adding a blocking agent having active hydrogen to a polyisocyanate such as tolylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and is blocked by heating. Examples include agents that dissociate to generate isocyanate groups that react with the functional groups in the resin component and cure.

  When these hardening | curing agents are contained, it is preferable that the content is 5-50 mass parts with respect to 100 mass parts of resin solid content in a composition. When the lower limit is less than 5 parts by mass, the curability is insufficient, and when the upper limit exceeds 50 parts by mass, the coating film may be too hard.

The amount of adhesion after applying the aqueous dispersion to the substrate and drying is not particularly limited depending on the application, but is 0.01 to 20 g / m ² , more preferably 0.2 to 10 g / m from the viewpoint of the drying speed. ² is desirable. If it is less than 0.01 g / m ² , it is difficult to obtain a uniform coating film, and if it exceeds 20 g / m ² , the drying time becomes long and efficient production becomes difficult.

  Although the conditions at the time of apply | coating an aqueous dispersion to a base material and drying are not specifically limited, It is preferable that it is 40-250 degreeC. If it is less than 40 degreeC, drying time will take time and it is not rational as industrial production. Also, the film may not be completely dried. On the other hand, if it exceeds 250 ° C., a high-performance drying furnace is required, which is not desirable. The drying method is not limited, but known methods such as a hot air drier, induction heating, near infrared heating, far infrared heating, indirect heating can be applied. If it is applied to a steel plate, a method may be used in which the steel plate is preheated, applied when heated, and dried with residual heat.

  Moreover, the water dispersion of this invention can be apply | coated to a to-be-coated object using a well-known method. The film thickness of the coating film thus obtained is 0.1 to 20 μm.

Next, the present invention will be specifically described using the following examples and comparative examples, but the present invention is not limited thereto. The characteristic value evaluation was performed by the following method. In the examples and comparative examples, “parts” simply means “parts by mass”.
In the examples, the characteristics of the coating film made of polyester, polyester aqueous dispersion, and aqueous dispersion were measured as follows.

1. Polyester resin composition Determined by ¹ H-NMR analysis using a nuclear magnetic resonance analyzer (NMR) Gemini-200 manufactured by Varian in chloroform D solvent.

2. Reduced viscosity ηsp / c (dl / g)
0.10 g of the polyester resin was dissolved in 25 cc of a mixed solvent of phenol / tetrachloroethane (mass ratio 6/4) and measured at 30 ° C. using an Ubbelohde viscosity tube.

3. Number average molecular weight Calculated from the results of GPC measurement at a column temperature of 35 ° C. and a flow rate of 1 ml / min using Waters Gel Permeation Chromatography (GPC) 150c with tetrahydrofuran as an eluent, and measured in terms of polystyrene Got the value. However, Showa Denko Co., Ltd. shodex KF-802, 804, 806 was used for the column.

4). Crystal melting point and glass transition temperature Using a differential scanning calorimeter (DSC) DSC-220 manufactured by Seiko Instruments Inc., 5 mg of a sample was sealed in an aluminum press-lid container, and the temperature was changed from −100 ° C. to 250 ° C. at 20 ° C. / And the maximum peak temperature of heat of fusion was determined as the crystalline melting point. The glass transition temperature is obtained from the temperature at the intersection of the base line extension below the glass transition temperature and the tangent indicating the maximum slope from the peak rising portion to the peak apex under the same conditions as in the measurement apparatus. It was.

5). Ionic group concentration 5-1. Carboxyl group concentration A 0.2 g sample was precisely weighed and dissolved in 20 ml of chloroform. Then, titration was performed with 0.01 N potassium hydroxide (ethanol solution) to obtain an equivalent amount of potassium hydroxide for the polyester resin, and converted into mg KOH / g unit. In addition, phenolphthalein was used as an indicator.
5-2. Sodium sulfonate concentration The sodium concentration was measured by atomic absorption, and the sodium sulfonate concentration was calculated and converted to mg KOH / g unit.

6). Storage stability The water dispersion was put into a 140 cc glass bottle, left in an incubator at 40 ° C., and stored for 30 days. After a predetermined number of days, the product was taken out from the incubator and visually confirmed. The case where there was no change was indicated as ◯, and the case where the system solidified was indicated as ×.

7). Water resistance 100 parts by weight of an aqueous polyester dispersion with 5 parts by weight of 2-propanol added as a coating solution, on the corona surface of a biaxially stretched polyester sheet (Toyobo Co., Ltd., Toyobo Ester, thickness 50 μm) A coating film of about 10 μm was obtained by coating with a hand coater and drying at 120 ° C. for 30 minutes. Without peeling the coating film from the polyester, it was immersed in warm water at 80 ° C. for 2 hours, and after drying, the coating film was rubbed and removed from the polyester sheet, and the weight of the polyester sheet was measured. The mass change of the coating film part was confirmed using this value, and the mass residual ratio was calculated according to the following formula.
(Mass residual rate [%]) = {(coating part mass after immersion in warm water) / (coating part mass before soaking in warm water)} × 100

8). Scratch resistance A coating film was prepared in the same manner as in the water resistance test, and a rubbing test was performed on the flat portion of an eraser (plastic eraser poppy 51 manufactured by KOKYUYO). After rubbing 30 times, a change in appearance was confirmed. The case where the appearance of the coating film did not change from before the test was evaluated as ◯, the case where the coating film was scratched was evaluated as Δ, and the case where the coating film was peeled off was evaluated as X.

Example of polyester resin synthesis In a reaction can equipped with a polyester resin (a-1) synthesis stirrer, thermometer, heater, cooling device, and distillation cooler, 980 parts by mass of terephthalic acid and 590 parts by mass of adipic acid , 770 parts by mass of ethylene glycol, 680 parts by mass of 1,4-butanediol, 3 parts by mass of Irganox 1330 (manufactured by Ciba-Geigy) and 1 part by mass of tetrabutyl titanate were charged for 4 hours while raising the temperature to 230 ° C. The esterification reaction was performed. After completion of the esterification reaction, 100 parts by mass of polytetramethylene glycol (manufactured by Mitsubishi Chemical Corporation, PTMG1000) is added to the reaction vessel, and then the pressure in the system is reduced to 10 torr over 60 minutes while raising the temperature to 240 ° C. The pressure was reduced to 1 torr or less and the polycondensation reaction was performed at 240 ° C. for 60 minutes. Thereafter, the polycondensation reaction was terminated by flowing nitrogen into the system and breaking the vacuum. Then, it cooled until the internal temperature became 220 degreeC with nitrogen filled in the system. After cooling, 90 parts by mass of ethylene glycol bisanhydro trimellitate was added, and again charged with nitrogen, and acid addition reaction was performed at 220 ° C. for 30 minutes. After completion of the reaction, the polyester resin was taken out and cooled to obtain polyester resin a-1. As a result of NMR analysis, the obtained polyester resin has a carboxylic acid component in a molar ratio of terephthalic acid / adipic acid / ethylene glycol bis trimellitate = 60/40/2 and a glycol component in a molar ratio of ethylene glycol / 1,4. -Butanediol / polytetramethylene glycol = 42/57/1. The measurement results are shown in Table 1 together with other resin physical properties.

Synthesis of polyester resins (a-2) to (a-5) Polyester resins (a-2) to (a-5) whose compositions are shown in Table 1 in the same manner as in the synthesis example of polyester resin (a-1). Synthesized. Polyester resins (a-2) to (a-4) used trimellitic anhydride instead of ethylene glycol bisanhydro trimellitate. The polyester resin (a-5) used both trimellitic anhydride and ethylene glycol bisanhydro trimellitate. In the same manner as the polyester resin (a-1), composition analysis and measurement of resin properties were performed. The results are shown in Table 1.

In Table 1,
T: terephthalic acid AA: adipic acid I: isophthalic acid SA: sebacic acid GCM: sodium 5-sulfonatoisophthalate EG: ethylene glycol BD: 1,4-butanediol HD: 1,6-hexanediol PTMG: polytetramethylene Glycol TMA: trimellitic acid TMEG: ethylene glycol bistrimellitate COOH: carboxyl group SO ₃ Na: sodium sulfonate group

Synthesis of Comparative Polyester Resins (a-6) to (a-10) Polyester resins (a-5) to (a-10) whose compositions are shown in Table 1 in the same manner as in the synthesis example of polyester resin (a-1) Was synthesized. As the polyester resin (a-7), both trimellitic acid and ethylene glycol bisanhydro trimellitate were used. For polyester resins (a-8) and (a-9), trimellitic acid was used in place of ethylene glycol bisanhydro trimellitate. Polyester resin (a-10) used neither ethylene glycol bisanhydro trimellitate nor trimellitic acid. In the same manner as the polyester resin (a-1), composition analysis and measurement of resin properties were performed. The results are shown in Table 2.

Production of Polyester Water Dispersion (b-1) Three-necked separable flask equipped with a thermometer, a condenser, and a stirring blade, 270 parts by mass of polyester resin (a-1), 180 parts by mass of methyl ethyl ketone, 60 parts by mass of isopropyl alcohol Was dissolved at 70 ° C. Next, after adding 5 parts by mass of ammonia as a base, 630 parts by mass of ion-exchanged water at 70 ° C. is added to disperse in water, and then distilled in a distillation flask until the fraction temperature reaches 100 ° C. Was added to obtain a polyester aqueous dispersion having a solid content concentration of 30%. The average particle diameter of finely dispersed particles present in the obtained polyester aqueous dispersion was 130 nm, and the dispersion coefficient was 42. The measurement results are shown in Table 3 together with other resin physical properties.

Production of polyester aqueous dispersions (b-2) to (b-5) Polyester resins (a-2) to (a-5) were used in the same manner as in the examples of the polyester aqueous dispersion (b-1). Polyester aqueous dispersions (b-2) to (b-5) were produced. Resin characteristics were measured in the same manner as the polyester aqueous dispersion (b-1). The results are shown in Table 3.

Synthesis of Comparative Polyester Water Dispersions (b-6) to (b-10) Polyester resins (a-6) to (a-10) were used in the same manner as in the polyester water dispersion (b-1) examples. Polyester aqueous dispersions (b-6) to (b-10) were produced. Resin characteristics were measured in the same manner as the polyester aqueous dispersion (b-1). The results are shown in Table 4.

  As is apparent from Tables 3 and 4, using a crystalline polyester resin having excellent water resistance and scratch resistance, the dispersion stability of the aqueous dispersion, the water resistance of the resulting film, and good mechanical properties It can be seen that a crystalline polyester resin aqueous dispersion capable of achieving both of the above can be obtained.

  A film excellent in water resistance and scratch resistance can be easily formed, and an aqueous dispersion of a crystalline polyester resin excellent in storage stability can be obtained, which greatly contributes to the industry. .

Claims (5)

  A crystalline polyester resin having a melting point of 80 ° C. or higher and an ionic group concentration of 5 to 30 mg KOH / g is dispersed, and the particle diameter of the dispersed polyester resin is in the range of 30 to 250 nm. Polyester resin water dispersion.   When the total amount of the dicarboxylic acid component and the glycol component is 100 mol%, the crystalline polyester resin is 40 mol% or more of terephthalic acid as the dicarboxylic acid component, and 30 to 95 mol of 1,4-butanediol as the glycol component. The polyester resin aqueous dispersion according to claim 1, wherein the polyester resin aqueous dispersion is% copolymerized.   The aqueous polyester resin dispersion according to claim 1 or 2, wherein the glycol component of the crystalline polyester resin comprises three or more components.   Polyester methylene glycol is contained in the glycol component of crystalline polyester resin, The polyester resin aqueous dispersion in any one of Claims 1-3 characterized by the above-mentioned.   The ionic group concentration derived from a sulfonic acid group among ionic groups of the crystalline polyester resin is 6 mgKOH / g or less, The polyester resin aqueous dispersion according to any one of claims 1 to 4.