JP3075901B2 - Method for producing water-dispersed coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates, concerning the preparation of water-dispersible coating composition. More particularly, the present invention relates to a method for producing fine particles aqueous dispersion coating composition are dispersed in water comprising a polyester resin containing sulfonate groups to impart hydrophilicity, magnetic tape, magnetic disk, printing Water dispersion that can be used for polyester easy-adhesive film useful for materials, plate making, OHP films, packaging materials, photographic films, capacitors, graphics, etc.
The present invention relates to a method for producing a coating composition .

[0002]

2. Description of the Related Art Biaxially stretched and heat-set polyester films are superior in mechanical strength, heat resistance, gas barrier properties, electrical properties and chemical resistance to films made of other resins, and are used in various industrial fields. It's being used. However, the surface is highly crystallographically oriented, so the surface has high cohesiveness,
Poor acceptability of paints, adhesives, inks, etc.

Therefore, when a synthetic resin layer is provided on the surface of a polyester film, the surface of the substrate is subjected to a corona discharge treatment, an ultraviolet irradiation treatment, a plasma treatment or a flame treatment in order to strengthen the adhesion therebetween, thereby activating the surface. After that, means for coating the synthetic resin layer coating film is applied.

However, although these means for activating the surface of the substrate can be expected to improve the adhesiveness due to the increase in the secondary bonding force due to the wetting of the coating material layer, the activity decreases with time. For these reasons, surface activating means are not always satisfactory.

As another method for increasing the receptivity of the polyester film substrate surface, an etching method has been proposed in which the film surface is swollen or partially dissolved with various chemicals. This involves immersing the film surface in an agent such as an acid, aqueous amine solution, trichloroacetic acid, or phenols, etching the surface to decompose, dissolve, relax, etc. the crystal orientation near the surface, and at the same time reduce the cohesiveness and reduce the binder. This is intended to enhance the adhesion to the resin, the effect is certain, and the adhesion between the base film and the synthetic resin coating layer provided thereon becomes strong. However, some of the chemicals used in this method are harmful, and may cause danger in handling or release volatiles of the chemicals into the atmosphere, so that thorough measures are taken to prevent contamination of the working environment. There are various disadvantageous problems in practical aspects such as the necessity of attention.

As a means similar to this method, there is a method in which a primer layer (undercoat layer) is previously provided on a base film, a surface layer different from the base film is formed thinly, and then a desired synthetic resin layer is coated. is there. For example, JP-A-53-2
No. 536 discloses a method of applying a coating on a polyester film. However, the coating is water-soluble and thus has poor moisture resistance, and uses an organic solvent as a solvent at the time of application. Therefore, the usage environment is often restricted.

Further, when forming an undercoat layer of a coating composition using a solvent, the coating process is generally performed in a process different from the film forming process, so that there is a danger that dust such as dirt and foreign substances will be introduced during the processing process. There is. For this reason, it is necessary to maintain the precise and delicate quality of advanced film products such as magnetic tape for video, magnetic tape for audio, magnetic tape for computer, radiographic film, photographic film for printing, diazo microfilm, etc. In applications that cannot be used, even if an easily adhesive surface is successfully formed, it cannot be used for these applications if there is a surface defect due to dust as a base film. In particular, when finishing the base film into a desired processed product, providing a primer coating process in order to modify the surface once rich in workability in the middle thereof lacks rationality and is economically or industrially advantageous. It can not be said.

[0008] Therefore, if the process of applying a primer (undercoat) is performed in an atmosphere in which dust is hardly generated, that is, in the process of manufacturing a polyester film, it is possible to sufficiently cope with the use of the above-mentioned advanced film processed products. Becomes

It is desired to perform an in-line undercoating process in such a film manufacturing process. As the undercoating treatment, for example, a method of applying an aqueous solution of polyester has been proposed, but there is a drawback such as poor moisture resistance due to the use of the aqueous solution.

An aqueous dispersion is particularly preferable for the in-line undercoating treatment. This is because the use of a coating composition using an organic solvent as a solvent causes contamination of the surrounding environment due to the escaped organic solvent, unfavorable conditions in terms of safety and hygiene, and adversely affects the film forming process.

As a method for dispersing a water-insoluble polyester resin in water, conventionally, (1) an emulsion or suspension is prepared by using an emulsifier, a dispersant, a suspension stabilizer and the like together with the polyester resin and water. (2) heating and melting the polyester resin and contacting and dispersing it with water or another medium to remove unnecessary medium; (3) preparing fine particles of the polyester resin in advance and dispersing the particles in water to stabilize the particles. (4) a method of once dissolving in a solvent capable of dissolving the polyester resin, mixing the obtained solution with water, and then removing the solvent to obtain an aqueous dispersion.

However, in the method (1), a large amount of emulsifier,
A dispersant is required, and furthermore, the emulsifier and the dispersant cause plasticization of the applied polyester resin, and the moisture resistance and heat resistance are reduced. In the method (2), since the high-temperature polyester comes into contact with water, the molecular weight is reduced due to the decomposition of the ester portion, and the adhesiveness and heat resistance are deteriorated. In the method (3), the process of fine particles is complicated, and the stability of the dispersion is poor. In the method (4), even if the polyester is simply dissolved in a solvent and then water is added, it is difficult to obtain a stable aqueous dispersion due to aggregation of the polyester particles. It has the drawback of being large and settling or degrading the quality of the coating.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coating film which solves the above-mentioned problems and can exert the effect of imparting easy adhesion under various production conditions of a biaxially stretched polyester film. the aqueous dispersion coating composition suitable for coating efficiently, and to provide a stable how prepared.

[0014]

SUMMARY OF THE INVENTION The present invention provides a water-dispersed coating composition comprising the steps of uniformly dispersing, in water, polyester resin fine particles having a sulfonic acid salt group in a molecule in an amount of 0.01 to 25 mol% with respect to a dicarboxylic acid component. (I) dissolving the polyester resin in an organic good solvent (A) that dissolves the polyester resin to obtain a solution;
i) Next, the solution and an organic poor solvent (B) that does not dissolve the polyester resin are mixed to a extent that fine particles do not substantially precipitate to form a mixed solution. (iii) Further, the mixed solution and the polyester are not dissolved. A water-dispersed coating composition comprising: mixing a mixture of an organic poor solvent (C) with water to form a stable aqueous dispersion; and (iv) distilling off each of the solvents by a separation means such as distillation. It is a method of manufacturing a product.

The polyester resin having a sulfonic acid group in the molecule in an amount of 0.01 to 25 mol% with respect to the dicarboxylic acid component used in the present invention comprises dicarboxylic acid or its ester-forming derivative and diol or its ester-forming derivative. Is a copolymerized linear saturated polyester synthesized from Examples of the dicarboxylic acid component of such a polyester include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, and 4,4'-
Biphenyldicarboxylic acid, phenylindanedicarboxylic acid, adipic acid, sebacic acid, succinic anhydride, 1,4-
Examples include cyclohexanedicarboxylic acid, dimer acid, itaconic acid, and phenylquinoxaline dicarboxylic acid. If necessary, trimellitic acid, pyromellitic acid, trimellitic anhydride, pyromellitic anhydride,
A small amount of a polycarboxylic acid such as butanetetracarboxylic dianhydride can be used. In addition, hydroxycarboxylic acids such as p-hydroxybenzoic acid and p- (β-hydroxyethoxy) benzoic acid can be used together with these components.

The diol component includes ethylene glycol, 1,4-butanediol, 1,3-propanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,6 -Cyclohexane dimethanol, 1,4-cyclohexane dimethanol,
p-xylylene glycol, trimethylolpropane,
Poly (ethylene oxide) glycol, poly (tetramethylene oxide) glycol, dimethylolpropionic acid, bisphenol A-alkylene oxide adduct,
And a small amount of a polyhydric hydroxy compound such as glycerin.

The polyester resin used in the present invention contains a sulfonate group in an amount of 0.01 to 25 mol% in the molecule. If a sulfonate group is introduced into the molecule when producing an aqueous dispersion of the polyester, a stable aqueous dispersion can be obtained. Further, by adjusting the amount of the sulfonate group, it is possible to adjust the hydrophilicity, adhesiveness, chargeability and the like of the film obtained by applying the aqueous dispersion to practically preferable performance. The amount of the sulfonic acid group is 0.01 to 25 mol%, preferably 0.01 to 10 mol%, more preferably 0.01 to 0.5 mol%, based on the dicarboxylic acid in the polyester resin molecule. . If this amount is 0.0
If it is less than 1 mol%, the water dispersibility decreases, and if it exceeds 25 mol%, the film obtained by applying the aqueous dispersion has poor hygroscopicity and chargeability. Further, the content is preferably 10 mol% or less for a film in which moisture absorption is particularly important, and is preferably 0.5 mol% or less for a film in which moisture absorption and charging properties are particularly important.

In order to introduce an organic sulfonate group into the molecule, for example, 5-Na sulfoisophthalic acid, 5-ammonium sulfoisophthalic acid, 4-Na sulfoisophthalic acid, 4-methylammonium sulfoisophthalic acid,
Na sulfoterephthalic acid, 5-K sulfoisophthalic acid,
Alkali metal sulfonate or amine sulfonate compounds such as 4-K sulfoisophthalic acid, 2-K sulfoterephthalic acid, and Na sulfosuccinic acid, Na sulfonate
Salt-containing bisphenol A-alkylene oxide adducts, sulfonic acid K base-containing hydroquinone alkylene oxide adducts, and the like can be used.

The polyester resin thus obtained is substantially insoluble in water or warm water.
Those having a solubility in 00 g of 0.1 g or less are preferred.

The organic good solvent (A) which dissolves the polyester resin used in the present invention is defined as the solvent (1)
A solvent having a solubility in water of 2% by weight or more and a boiling point of 120 ° C. or less, such as tetrahydrofuran and dioxane, and particularly an organic solvent containing tetrahydrofuran as a main component. Is preferred. Hereinafter, this organic solvent is referred to as a solvent (A).

The organic poor solvent (B) which does not dissolve the polyester resin used in the present invention has a solubility of less than 1 g of the polyester resin in 100 g of the solvent, a solubility in water of 2% by weight or more, and a boiling point of 100%. Is a solvent having a temperature of 120 ° C. or lower. Hereinafter, this solvent is referred to as a solvent (B). Examples of the solvent (B) include nitriles such as acetonitrile and propionitrile, acetone, methyl ethyl ketone,
Examples thereof include ketones such as methyl isobutyl ketone, alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, esters such as methyl acetate, and aromatic hydrocarbon solvents such as toluene and hexane, preferably nitriles and ketones. And acetonitrile is particularly preferred.

The organic poor solvent (C) which does not dissolve the polyester resin used in the present invention has a solubility of less than 1 g of the polyester resin in 100 g of the solvent, a solubility in water of 2% by weight or more, and a boiling point of 100%. Is a solvent having a temperature of 140 ° C. or lower. Hereinafter, this solvent is referred to as a solvent (C). Examples of the solvent (C) include alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, ketones such as acetone and methyl ethyl ketone, ethers such as methylcellosolve and ethylcellosolve, and nitriles such as acetonitrile and propionitrile. Examples thereof include esters such as methyl acetate, and aromatic hydrocarbon solvents such as toluene and hexane, and are preferably methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, and particularly preferably methyl. Alcohols such as alcohol, ethyl alcohol and isopropyl alcohol (n- or iso-).

The solvents (B) and (C) may be the same solvent, but the solubility of the polyester resin in the solvent (C) is preferably smaller than that of the solvent (B).

In the present invention, first, the polyester resin is dissolved in the solvent (A), and then the solvent (B) is mixed to the extent that the polyester resin does not precipitate to form a mixed solution. The mixed solution is further mixed with water and the solvent (C). To precipitate the polyester resin fine particles, and then the solvent is distilled off from the resulting mixed liquid containing the fine particles.

The dissolution of the polyester resin can be carried out efficiently with the solvent (A). At this time, an arbitrary concentration can be selected as the dissolution concentration of the polyester resin.
Or less, more preferably 10% by weight or less. The lower limit of this concentration is preferably 1% by weight. If the concentration exceeds 20% by weight, the concentration of the fine particles in the system at the time of the generation of the fine particles becomes high, and the adhesion of the particles is promoted, which is not preferable. The dissolution of the polyester resin is preferably performed by heating, and particularly preferably, the polyester is added to tetrahydrofuran and dissolved under heating. The solvent described in the above-mentioned solvent (B) may be contained in the solvent (A) as long as the amount does not hinder the dissolution of the polyester resin. For example, tetrahydrofuran and acetonitrile,
Combinations of tetrahydrofuran and methyl isobutyl ketone, dioxane and methyl ethyl ketone, and the like can be given, and particularly preferred is tetrahydrofuran and acetonitrile.

Further, by mixing and adjusting the solvent (B), fine particles can be deposited when the polyester resin fine particles are precipitated. At that time, the solvent (B) in the mixed solution
Is preferably slightly smaller than the rate at which the precipitation of the polyester resin starts (limit rate). If the ratio exceeds the limit ratio, large particles are formed, and the stability of the dispersion is impaired. For example, gelation proceeds during storage of the dispersion or sedimentation occurs due to some shock, which is not preferable.

The mixing of the mixed solution of water and the solvent (C) with the mixed solution of the polyester resin is performed in the vicinity of the beginning of the precipitation of fine particles. The method of adding a solution is preferable because the precipitated polyester becomes fine particles. The mixing ratio of water and the solvent (C) at that time is adjusted depending on the structure of the polyester to be precipitated, but it is preferable to carry out the mixing at a ratio that ensures formation of fine particles and suppresses swelling of the particles by the solvent (A) as much as possible. . The mixing ratio of water to the solvent (C) is 1/5 to 5/1, preferably 1/3 to 3/1, and more preferably 1/3 to 2/1 by weight. If the mixing ratio is too high, large particles are formed, and the stability of the dispersion is impaired. On the other hand, if the mixing ratio is too low, secondary aggregation of precipitated fine particles is promoted, which is not preferable.

To remove the organic solvent from the mixed solution containing the polyester resin fine particles, distillation is performed. By performing distillation under reduced pressure, the system can be kept at a low temperature,
Viscosity due to re-dissolution of the dispersed resin fine particles does not occur, and a high-concentration dispersion can be produced. Decompression degree is 600
mmHg or less, preferably 100 mmHg or less. The amount of the residual solvent in the obtained aqueous dispersion is preferably lower for reasons such as contamination of the working environment during in-line coating as described in the related art. As the amount of residual solvent,
Preferably 5% by weight or less, most preferably 0.1% by weight
It is as follows. The average particle size of the fine particles in the aqueous dispersion is 100
It is preferably in the range of 10 to 10 nm.

If necessary, the aqueous dispersion thus obtained may contain other resins, surfactants, lubricants, organic or inorganic fine particles,
Fillers, cross-linking agents, dispersants, ultraviolet absorbers and the like can be added.

In particular, a necessary amount of a surfactant can be added to increase the stability of the solution. Further, this surfactant may be added in advance to the polyester resin solution, or may be added to water for dispersion. As the surfactant, the surface tension of the aqueous dispersion is set to 50 dyne / cm.
Or less, preferably 40 dyne / cm or less,
Those that promote wetting to the polyester film are preferable, and can be used from among many known anionic surfactants, cationic surfactants, nonionic surfactants, and the like. Anionic surfactants and cationic surfactants can be used. Surfactants are preferred. Effective surfactants include polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl sulfate, alkyl sulfonate, alkyl sulfosuccinate, quaternary amine Salt compounds, alkylamine compounds and the like can be mentioned. It is desirable to use the surfactant in an amount of 1 to 50 parts by weight based on 100 parts by weight of the polyester resin. In addition, the film may be subjected to a corona treatment before the application of the aqueous dispersion, in which case the amount of the surfactant may be reduced or not used.

The concentration of the polyester resin in the aqueous dispersion thus obtained is preferably 0.5 to 30% by weight, and is preferably adjusted to 1 to 10% by weight when applied to a film.

The aqueous polyester dispersion thus obtained can be coated on a polyester film to improve the adhesiveness of the film. Any known coating method can be applied as a method for applying the aqueous dispersion. For example, a roll coating method, a gravure coating method, a roll brushing method, a spray coating, an air knife coating, an impregnation method, a curtain coating method, or the like may be applied independently or in combination.

In the step of applying a coating, the polymer is immediately melt-extruded and cast into an unstretched film.
Or, a film immediately after being stretched in one direction, either vertically or horizontally, or a non-heat-fixed film surface layer that has been biaxially stretched vertically or horizontally (that is, a surface layer before the completion of oriented crystal). The film surface layer immediately after the uniaxial stretching in the machine direction is particularly preferable. It is preferable that the film after the application of the aqueous dispersion is further subjected to a stretching treatment. Here, the stretching treatment refers to a treatment including any one of heat treatments such as uniaxial stretching in the vertical or horizontal direction, biaxial stretching in the vertical and horizontal directions, heat setting or thermal relaxation.

A film suitable for applying the aqueous polyester dispersion of the present invention comprises a linear saturated polyester synthesized from an aromatic dibasic acid or its ester-forming derivative and a diol or its ester-forming derivative. Film. Preferred examples of the linear saturated polyester include polyethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, and poly (1,4-cyclohexylene dimethylene terephthalate). Blends with other resins are also included. The above-described linear saturated polyester resin is melt-extruded, formed into a film by a conventional method, and subjected to orientation crystallization and heat treatment crystallization (heat setting). Particularly, a polyethylene terephthalate film or a polyethylene naphthalenedicarboxylate film is preferred. The thickness of these films is usually 1 to 350 μm.

The thickness of the coating film applied by the method of the present invention can be arbitrarily selected.
m, particularly preferably 0.01 to 0.2 μm.

The easily adhesive layer film coated with the aqueous polyester dispersion of the present invention may be made of cellophane ink, magnetic paint, gelatin composition, linseed oil-based offset ink, electrophotographic toner composition, chemical matte paint, diazo paint, It shows a very wide range of adhesion and adhesion performance to heat sealability-imparting compositions, inorganic coating-forming substances and metal vapor deposition substances.

[0037]

The present invention will be described below in more detail with reference to examples. The measurement items in the examples were measured by the following methods. Further, “parts” means “parts by weight”.

(1) Adhesive force of magnetic paint A paint for evaluation is applied to a primer-coated polyester film by a Meyer bar so as to have a thickness of about 4 μm after drying, and dried at 100 ° C. for 3 minutes. Thereafter, aging was performed at 60 ° C. for 24 hours, and then Scotch tape No. 600 (3
(M company) 12.7 mm wide and 15 cm long are adhered so as not to contain air bubbles, and JIS C2701 (197
5) Using a manual load roll as described above, bring the tape into close contact, and cut it out into a tape width. The peel strength when this is peeled 180 degrees is measured.

[Evaluation paint] Urethane resin Nipporan 2304 (manufactured by Nippon Polyurethane) 25 parts PVC / vinegar resin Esrec A (manufactured by Sekisui Chemical) 50 parts Dispersant Ratio P (manufactured by RIKEN Vitamin) 1 part in terms of solid content Agent CTX-860 (manufactured by Toda Chemical Co., Ltd.) (500 parts) is dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to make a 40% solution, and the mixture is dispersed with a sand grinder for 2 hours. Thereafter, 25 parts (in terms of solid content) of coronate L as a cross-linking agent are added and stirred well to obtain a magnetic paint.

(2) Chargeability A primer-coated polyester film having a width of 400 mm and a length of 3000 m was measured at 23 ° C. for 120 m under an atmosphere of 72% RH.
The film is rewound at a rate of / minute, and the peeling charge amount (average value) is measured by a Model-230 static electricity measuring device manufactured by Hugri Electronics Co., Ltd.

(3) Blocking property 10 c after the front and back surfaces of the polyester film are combined.
It is cut into a square of mx 15 cm, a load of 50 kg / cm ² is applied to this in an atmosphere of 50 ° C x 80% RH for 17 hours, and then the peel strength of this 10 cm width is measured. The peeling speed at this time is 100 mm / min. When the peel strength is 15 g / 10 cm or less, preferably 10 g / 10 cm or less, and more preferably 5 g / 10 cm or less, there is no practical problem.

Example 1 (Production of a water-dispersed coating composition) A polyester copolymer (hereinafter referred to as "copolymer") having a component indicated by A-1 in Table 1 (5 parts) was prepared as a solvent (A) using tetrahydrofuran ( (Hereinafter referred to as "THF") in 95 parts to give a 5% by weight solution. Next, 52 parts of acetonitrile as a solvent (B) was added to this solution, and the mixture was stirred and mixed to obtain a mixed solution in which no copolymer was precipitated. This mixed solution is mixed with water 3
The mixture was gradually added to a mixture of 2 parts and 80 parts of ethanol with stirring to precipitate copolymer fine particles. The mixed solution containing the fine particles of the copolymer thus obtained was distilled under reduced pressure of 50 mmHg to distill off a part of the solvent and water, and further filtered through a filter having a mesh size of 4 μm to obtain 17% by weight of the copolymer.
(Hereinafter referred to as "water dispersion").

(Application of Aqueous Dispersion) An unstretched film of polyethylene terephthalate having an intrinsic viscosity of 0.63 (containing silica fine particles as a lubricant) was stretched 2.5 times in the machine direction,
On one side, a surfactant (HLB = 1) was added to the aqueous dispersion.
2.8 polyoxyethylene nonylphenyl ether)
And water, and the solid content ratio of the copolymer and the surfactant is 9
The composition was adjusted and applied to an aqueous dispersion containing 0/10 and 5% by weight of a nonvolatile component. Next, the coated film is stretched 3.7 times in the horizontal direction, further stretched 1.8 times in the vertical direction and 1.2 times in the horizontal direction, and heat-treated at 200 ° C. for 4 seconds, and then into a 9 μm biaxially stretched polyester film. An easily-adhesive polyester film coated with a copolymer layer (hereinafter, referred to as an "easily-adhesive film") was obtained. The coating thickness of the copolymer layer was 0.03 μm. Table 2 shows the evaluation results of the obtained easily adhesive films.

Comparative Example 1 The properties of a film obtained in the same manner as in Example 1 except that the aqueous dispersion was not applied are shown in Table 2.

Example 2 In Example 1, polyethylene-2,6-naphthalenedicarboxylate (intrinsic viscosity 0.65, containing calcium carbonate) as a base film
Table 2 shows the properties of the easy-adhesive film obtained in the same manner as in Example 1 except that the above-mentioned was used.

[Examples 3 to 6] Table 2 shows the evaluation results of the easily adhesive films obtained in the same manner as in Example 1 except that the copolymers shown in Table 1 were applied at the coating thicknesses shown in Table 2. .

Example 7 (Production of Aqueous Dispersion) 3 parts by weight of a copolymer shown in A-5 of Table 1 as a solvent (A) was dissolved in a mixed solution of 70 parts of THF and 27 parts of dioxane, and 3% by weight The solution was used. Next, a mixed solution of 40 parts of acetonitrile and 10 parts of methyl ethyl ketone was added to this solution as a solvent (B), and the mixture was stirred and mixed to obtain a mixed solution in which no copolymer was precipitated. This mixed solution was gradually added to a mixed solution of 40 parts of water and 80 parts of methanol while stirring to precipitate fine particles of a copolymer. The mixed solution containing the fine particles of the copolymer thus obtained was distilled under reduced pressure of 100 mmHg to distill off a part of the solvent and water, and further filtered with a filter having a mesh size of 4 μm to obtain 10% by weight of the copolymer. Was obtained.

(Application of Aqueous Dispersion) The properties of an easily adhesive film obtained by applying the above aqueous dispersion in the same manner as in Example 1 are shown in Table 2.
Shown in

[Examples 8 to 9] Using the copolymers shown in Tables A-6 and A-7, an aqueous dispersion was prepared in the same manner as in Example 7, and the coating thickness shown in Table 2 was used. Example 1 except for coating
Table 2 shows the evaluation results of the easily adhesive films obtained in the same manner as in Example 1.

Comparative Example 2 5 parts of the copolymer shown in A-1 of Table 1 was dissolved in 95 parts of THF to prepare a 5% by weight solution. Next, this solution was gradually added to 110 parts of water while stirring, and an attempt was made to produce an aqueous dispersion by precipitating the copolymer particles and further removing the solvent. No dispersion was obtained. Since the aqueous dispersion was poor, application to the film and evaluation of the film were not performed.

Comparative Example 3 A film obtained in the same manner as in Example 1 except that the copolymer shown in A-8 of Table 1 was used was wound around a width of 800 mm and a length of 3000 m at 60 ° C., 80%
After storage under RH humidity for 3 days, the product was taken out and blocked, and could not be put to practical use. Film evaluations other than blocking properties were not performed.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

According to the present invention, a water-dispersed coating composition in which fine particles made of a water-insoluble polyester resin having excellent adhesion, moisture resistance and blocking resistance are uniformly dispersed is efficiently and stably prepared. A method of manufacturing can be provided.

Continuation of the front page (56) References JP-A-4-335059 (JP, A) JP-A-7-216210 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 3 / 07 C08L 67/00-67/04 C09D 167/00-167/04 C09J 167/00-167/04

Claims (2)

(57) [Claims] 1. A method for producing a water-dispersed coating composition by uniformly dispersing, in water, polyester resin fine particles having a sulfonic acid salt group in a molecule in an amount of 0.01 to 25 mol% with respect to a dicarboxylic acid component, comprising: ) Good organic solvent for dissolving the polyester resin (A)
(Ii) Then, the solution is mixed with an organic poor solvent (B) that does not dissolve the polyester resin in a range where the fine particles do not substantially precipitate, to obtain a mixed solution. iii) Further, the mixed solution is mixed with a mixed solution of an organic poor solvent (C) which does not dissolve the polyester and water to form a stable aqueous dispersion, and (iv) the respective solvents are distilled off. A method for producing a water-dispersed coating composition comprising: 2. The process for producing a water-dispersed coating composition according to claim 1, wherein the organic good solvent (A) for dissolving the polyester resin is an organic solvent containing tetrahydrofuran as a main component.