JP2007177026A - Resin for aqueous polyester dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin for an aqueous polyester dispersion, which shows no discoloration during polymerization, has a relatively low cost, and is friendly to the environment without containing a heavy metal, and to provide a method for producing the same and an aqueous polyester dispersion excellent in adhesion to a material to be coated. <P>SOLUTION: The resin for an aqueous polyester dispersion is a polyester mainly composed of an aromatic dicarboxylic acid component and a glycol component, wherein the resin has an acid value of 3-40 mg KOH/g and a hydroxyl value of 20 mg KOH/g or less, and contains 100-400 ppm of a solid solution composed of a magnesium compound and an aluminum compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention is a polyester-based aqueous dispersion resin that is suitable as a resin for a polyester-based aqueous dispersion with a high acid value and a high hydroxyl value, and does not contain heavy metals represented by antimony, and its production. The present invention relates to a method and an aqueous polyester dispersion.

  The polyester resin has very good adhesion to molded articles and films such as polyethylene terephthalate (hereinafter referred to as PET), polybutylene terephthalate (hereinafter referred to as PBT), various metals, and vinyl chloride. It is used in large quantities as a resin for inks and adhesives by dissolving in an organic solvent. However, in recent years, paints, inks, and adhesives that do not use organic solvents have been demanded from the viewpoint of the environment, and it is required to supply polyester as an aqueous dispersion.

  As a method for obtaining an aqueous dispersion of polyester, there is a method in which a carboxyl group is imparted to the polyester and this is neutralized with an amine or the like and stabilized. At this time, in order to obtain a polyester having a carboxyl group and a hydroxyl group, a method of once producing a polyester having a hydroxyl group at the end and adding a dicarboxylic acid thereto, or depolymerizing with a dicarboxylic acid is common.

  When producing a polyester resin having hydroxyl groups at both ends, it is common to use a polycondensation catalyst, but antimony compounds represented by antimony trioxide have been widely used as the polycondensation catalyst. Antimony trioxide is a polycondensation catalyst that is inexpensive and has excellent catalytic activity. However, in recent years, problems regarding the safety of antimony have been pointed out in Europe and the United States from an environmental viewpoint.

  Studies on polymerization catalysts that replace antimony-based catalysts such as antimony trioxide have also been conducted, and titanium compounds and tin compounds typified by tetraalkoxy titanates have already been proposed, but polyester resins produced using these compounds are There is a problem that coloring during polymerization is intense.

  As an attempt to overcome the problem when such a titanium compound is used as a polymerization catalyst, for example, Patent Document 1 proposes a method of using tetraalkoxy titanate as a polymerization catalyst simultaneously with a cobalt compound. However, with this technique, although coloration when tetraalkoxy titanate is used as a polymerization catalyst is reduced, thermal decomposition of the polyester resin cannot be effectively suppressed. Furthermore, the cobalt compound has been pointed out as having a safety problem as with antimony trioxide.

  As another attempt to suppress thermal degradation of polyester polymerized using a titanium compound as a catalyst, Patent Document 2 discloses a method of adding a phosphorus compound after polymerizing a polyester using a titanium compound as a catalyst. Yes. However, it is impractical to effectively mix the additives after polymerization, resulting in a complicated production process and an increase in cost.

Germanium compounds have already been put to practical use as polymerization catalysts having excellent catalytic activity other than antimony compounds, and excellent color tone and thermal stability. However, this catalyst is very expensive, Since it tends to be distilled out of the system, there is a problem that the catalyst concentration in the reaction system changes and it becomes difficult to control the polymerization, and there is a problem in using it as a catalyst main component.
Japanese Patent Laid-Open No. 2002-293906 JP-A-10-259296

  The present invention solves the above-mentioned problems, is not colored at the time of polymerization, is not expensive, and does not contain heavy metals. It is a technical problem to provide a polyester-based aqueous dispersion having excellent adhesion.

  The inventor of the present invention has arrived at the present invention as a result of intensive studies to solve the above problems.

That is, the gist of the present invention is as follows.
(1) A polyester mainly composed of an aromatic dicarboxylic acid component and a glycol component, having an acid value of 3 to 40 mg KOH / g, a hydroxyl value of 20 mg KOH / g or less, and a solid solution composed of a magnesium compound and an aluminum compound. Polyester aqueous dispersion resin characterized by containing ~ 400 ppm.
(2) A magnesium compound as a polymerization catalyst for producing a polyester aqueous dispersion resin mainly comprising an aromatic dicarboxylic acid component and a glycol component and having an acid value of 3 to 40 mg KOH / g and a hydroxyl value of 20 mg KOH / g or less. A method for producing a polyester-based aqueous dispersion resin, comprising adding 100 to 400 ppm of a solid solution comprising aluminum and an aluminum compound.
(3) A polyester-based aqueous dispersion obtained by dispersing or dissolving the polyester-based aqueous dispersion resin described in (1) in an aqueous medium.

  According to the present invention, there is no coloring during polymerization, the cost is not high, and the polyester-based aqueous dispersion resin is free from heavy metals such as antimony and is considered for environmental problems, its production method, and coating A polyester-based aqueous dispersion having excellent adhesion to an object is provided.

  Hereinafter, the present invention will be described in detail.

  The polyester-based aqueous dispersion resin of the present invention (hereinafter sometimes abbreviated as “resin”) is a polyester mainly composed of an aromatic dicarboxylic acid component and a glycol component. In the present invention, as the aromatic dicarboxylic acid component, Are mainly composed of aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, phthalic acid, naphthalenedicarboxylic acid, and aliphatics such as adipic acid, sebacic acid, dodecanedioic acid as required Dicarboxylic acids, and trivalent or higher carboxylic acids such as trimellitic acid and pyromellitic acid can be used in combination.

  As the glycol component, those mainly composed of aliphatic glycols such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, etc. are used and necessary. Depending on the case, alicyclic alcohols such as 1,4-cyclohexanedimethanol and trihydric or higher alcohols such as trimethylolpropane, glycerin and pentaerythritol can be used in combination. If necessary, hydroxycarboxylic acids such as 4-hydroxybenzoic acid and ε-caprolactone may be used in combination.

  The resin of the present invention is required to have an acid value of 3 to 40 mg KOH / g, preferably 5 to 39 mg KOH / g. If the acid value is less than 3 mg KOH / g, it becomes difficult to make the resin water-based. On the other hand, when the acid value exceeds 40 mgKOH / g, the physical properties of the coating surface are significantly lowered with a decrease in molecular weight.

  In addition, the resin of the present invention needs to have a hydroxyl value of 20 mg KOH / g or less, preferably 5 to 17 mg KOH / g. If the hydroxyl value exceeds 20 mg KOH / g, the water resistance decreases.

 Furthermore, the resin of the present invention needs to contain 100 to 400 ppm, preferably 150 to 350 ppm of a solid solution composed of a magnesium compound and an aluminum compound. If the content of the solid solution is less than 100 ppm, the catalytic activity at the time of polymerization is not sufficient, and if it exceeds 400 ppm, the color tone of the resulting resin deteriorates, or the solid solution aggregates in the resin and causes foreign matters, thereby impairing the appearance. It will be.

  In addition, the solid solution which consists of a magnesium compound and an aluminum compound is cheaper than a germanium compound, and can suppress a raise of cost rather than the case where a germanium compound is used as a polymerization catalyst.

  In the present invention, a solid solution composed of a magnesium compound and an aluminum compound is a solid in which each is uniformly melted, and a part of these crystal lattices can be replaced by other atoms to change the composition. The substance amount (mole) ratio in the solid solution is preferably an aluminum / magnesium ratio of 0.1 to 10, more preferably 0.2 to 5.

  Examples of the magnesium compound include magnesium hydroxide, magnesium carbonate, magnesium acetate, magnesium acetylacetonate, and carboxylic acids other than acetic acid. Magnesium hydroxide and magnesium carbonate are particularly preferable.

  In addition, the above-described aluminum compound is not particularly limited. For example, aluminum hydroxide, aluminum hydroxide chloride, aluminum formate, aluminum acetate, aluminum propionate, aluminum oxalate, aluminum acrylate, aluminum stearate, aluminum benzoate Carboxylates such as aluminum chloride, inorganic acid salts such as aluminum chloride and aluminum phosphate, aluminum alkoxides such as aluminum methoxide, aluminum ethoxide, aluminum n-propoxide, aluminum n-butoxide, aluminum acetylacetonate, aluminum acetylacetate Aluminum chelate compounds such as aluminum ethyl acetate, organic aluminum such as trimethylaluminum and triethylaluminum Compounds and partial hydrolyzates thereof, aluminum oxide, metallic aluminum, and the like. Of these, hydroxides, carboxylates and inorganic acid salts are preferred, and among these, aluminum hydroxide, aluminum acetate and aluminum chloride are particularly preferred.

  The magnesium compound and aluminum compound used in the present invention may be a solid solution using two or more compounds in either one or both.

  The solid solution composed of a magnesium compound and an aluminum compound in the present invention may contain other metals other than magnesium and aluminum as necessary. In that case, 70 mass% or more is composed of the magnesium compound and the aluminum compound. Preferably there is. Examples of other metals include titanium, manganese, niobium, tantalum, tungsten, indium, zirconium, hafnium, silicon, nickel, and gallium.

  The resin of the present invention contains additives such as an anti-oxidant such as a hindered phenol compound, a fluorescent agent, a color tone improver such as a dye, and a light-proofing agent as long as the effects of the present invention are not impaired. May be.

  Next, a method for producing a polyester-based aqueous dispersion resin will be described.

  The production method of the present invention comprises a polymerization catalyst for producing a polyester-based aqueous dispersion resin mainly comprising an aromatic dicarboxylic acid component and a glycol component and having an acid value of 3 to 40 mg KOH / g and a hydroxyl value of 20 mg KOH / g or less. As described above, 100 to 400 ppm of a solid solution composed of a magnesium compound and an aluminum compound is added.

  Specifically, for example, it can be produced as follows. First, raw materials such as the dicarboxylic acid component and the polyhydric alcohol component (including their ester-forming derivatives) are charged into an esterification reaction tank, and a temperature of 200 to 280 ° C. in a nitrogen gas atmosphere for 2 to 10 hours. Esterification reaction or transesterification reaction is performed. Next, it is transferred to a polycondensation reaction tank, and a slurry of a solid solution composed of a magnesium compound and an aluminum compound is added so as to have a concentration of 100 to 400 ppm, and a polycondensation reaction is performed under a reduced pressure of 200 to 300 ° C. and 5 hPa or less. A polyester resin having a high degree of polymerization with a hydroxyl group at the end is obtained. Then, the target resin can be obtained by adding carboxylic acid and depolymerizing at 220-290 degreeC reaction temperature for 1 to 5 hours. At this time, a glycol component can also be added in order to simultaneously control the hydroxyl value.

  In addition, it is preferable from the surface of the hot water resistance of a film that the carboxyl group which contributes to water-ization of a polyester resin is unevenly distributed at the terminal of the resin molecular chain rather than existing in the resin skeleton.

  As described above, when a solid solution composed of a magnesium compound and an aluminum compound is added to the polycondensation reaction tank, it is added as a solid solution slurry. As a dispersion medium used for the solid solution slurry, ethylene glycol, 1,2 -Propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, etc. Among these, ethylene glycol is particularly preferable.

  Further, in order to prevent the solid solution from aggregating into a foreign substance in the polyester-based aqueous dispersion resin and causing the coating surface to become abnormal in appearance, a predetermined amount of the solid solution is added to a dispersion medium such as ethylene glycol and mixed by stirring. Then, it is preferable to perform ultrasonic treatment and add to the polycondensation reaction tank.

  The frequency of the ultrasonic wave may be in a normal frequency range, and for example, a range of about 20 kHz to 100 kHz can be applied. As an oscillation source for generating ultrasonic waves, known means may be used, and examples thereof include a piezoelectric vibrator using crystal, an electrostrictive oscillator using nickel or ferrite, and the like. In addition, the ultrasonic treatment time is preferably in the range of 0.5 to 5 hours.

  Next, the polyester-based aqueous dispersion of the present invention (hereinafter sometimes referred to as an aqueous dispersion) will be described.

  The aqueous dispersion of the present invention is one in which the above polyester-based aqueous dispersion resin is dispersed or dissolved in an aqueous medium. The aqueous medium is a medium composed of a liquid mainly composed of water and an organic solvent, and may contain a basic compound described later.

  In the aqueous dispersion of the present invention, the content of the polyester-based aqueous dispersion resin can be appropriately selected depending on the film forming conditions, the desired thickness and performance of the resin coating, and is not particularly limited. In order to maintain an appropriate viscosity and to form a good film, the content is preferably 10 to 45% by mass.

  In the aqueous dispersion of the present invention, the carboxyl group of the polyester-based aqueous dispersion resin is preferably neutralized by a basic compound, and if neutralized, by the electric repulsive force between the generated carboxyl anions. Aggregation between the fine particles is prevented, and stability is imparted to the aqueous polyester dispersion.

  As the above basic compound, those which are easy to evaporate are preferable. Triethylamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobis Propylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, N-methylmorpholine , N-ethylmorpholine and the like. Of these, triethylamine is most preferred.

  As a usage-amount of a basic compound, according to the quantity of the carboxyl group contained in the resin for polyester-type aqueous dispersions, the quantity which can at least partially neutralize this, ie, 0.4-1 with respect to a carboxyl group. A 5 times equivalent is most preferred. If the amount of the basic compound used is 0.4 times equivalent or more, sufficient storage stability can be imparted, and if it is 1.5 times equivalent or less, the aqueous dispersion will not be significantly thickened.

  When the resin is made water-based, the polyester used for paints, adhesives, etc. is obtained by dispersing in a mixed solution of a water-soluble organic solvent and water to obtain the aqueous dispersion of the present invention and then removing the organic solvent. Generally, it is a system aqueous dispersion.

  As the organic solvent to be used, those having a solubility in water at 20 ° C. of 10 g / L or more are preferable, and the boiling point of the organic solvent is preferably 150 ° C. or less. When the boiling point of the organic solvent exceeds 200 ° C., it becomes difficult to evaporate from the resin film by drying.

  Specific examples of the organic solvent used in the present invention include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, alcohols such as tert-amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, Ethers such as tetrahydrofuran and dioxane, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-sec-butyl, acetic acid-3-methoxybutyl, methyl propionate, ethyl propionate, Carbonic acid Esters such as diethyl and dimethyl carbonate, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether , Glycol derivatives such as diethylene glycol monobutyl ether, diethylene glycol ethyl ether acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether acetate, and further, 3-methoxy-3-methylbutanol, 3-methoxy Butanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate and the like, it may be mixed using two or more kinds.

  Among the above organic solvents, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, methyl ethyl ketone, tetrahydrofuran, ethylene glycol monobutyl ether, and the like are preferable because the organic solvent can be easily removed from the aqueous medium.

  Furthermore, the aqueous dispersion of the present invention includes various agents such as a leveling agent, an antifoaming agent, an anti-waxing agent, a pigment dispersant, an ultraviolet absorber, and an aqueous resin such as an aqueous urethane resin and an aqueous acrylic resin as necessary. A pigment or dye such as a composition, titanium oxide, zinc white, or carbon black may be added.

  Next, the example of a manufacturing method of a polyester-type aqueous dispersion is demonstrated. First, an apparatus is provided that is equipped with a tank into which a liquid can be charged and that can appropriately stir a mixture of an aqueous medium and a resin powder or granular material charged into the tank. As such a device, a device widely known to those skilled in the art as a solid / liquid stirring device or an emulsifier can be used. Usually, a simple lid is provided and used under normal pressure or slight pressure. However, an apparatus capable of pressurization of 0.1 MPa or more can be used as necessary.

  An aqueous medium composed of water, a basic compound and an organic solvent, and a granular or powdery polyester aqueous dispersion resin are put into a tank of this apparatus, and the mixture is stirred and mixed at a temperature of 40 ° C. or less to roughen. Disperse. At this time, when the shape of the resin for the polyester-based aqueous dispersion is a sheet or a large lump that is difficult to coarsely disperse, the following heating process may be performed. Next, while maintaining the temperature in the tank at 45 ° C. or higher, the polyester aqueous dispersion resin is sufficiently aqueousized by continuing stirring for 15 to 120 minutes, and then cooled to 40 ° C. or lower with stirring. A polyester-based aqueous dispersion can be obtained.

  As a heating method in the tank, heating from the outside of the tank is preferable, for example, a method of performing external heating using an oil bath or a water bath, a tank provided with a jacket, and oil heated in the jacket or The method of heating the inside of a tank externally by flowing water can be mentioned. As a cooling method in a tank, the method of naturally cooling at room temperature and the method of cooling using 0-40 degreeC oil or water in the said heating method can be mentioned, for example.

  In addition, before putting resin for polyester-type aqueous dispersion into the said tank, you may perform a jet grinding process to the said resin as needed. Jet pulverization here refers to a fluid such as a polyester-based aqueous dispersion resin that is ejected from a pore such as a nozzle or slit under high pressure to cause resin particles or resin particles to collide with a collision plate. In addition, the resin particles are further refined by mechanical energy. Specific examples of devices for this purpose include the homogenizer manufactured by APVGAULIN, the micro-fluidizer M-110E / H manufactured by Mizuho Industries, and the product manufactured by Sonic. Sonorator A-HP type etc. are mentioned.

  Next, by removing the organic solvent from the aqueous polyester dispersion of the present invention obtained as described above, an aqueous polyester dispersion used for paints, adhesives and the like can be obtained.

  Examples of the method for removing the organic solvent include a method in which the aqueous polyester dispersion is heated with stirring under normal pressure or reduced pressure, and the organic solvent is distilled off. The content of the organic solvent can be quantified by gas chromatography. When the content is 0.5% by mass or more, the operation of distilling off the organic solvent may be repeated as described above. Further, since the solid content concentration is increased by distilling off the aqueous medium, for example, in the case where the viscosity increases and the workability deteriorates, water may be added to the polyester-based aqueous dispersion in advance. it can.

  As described above, the aqueous dispersion used for paints, adhesives and the like is obtained by preparing a uniform liquid by dispersing or dissolving the polyester-based aqueous dispersion resin in an aqueous medium. Here, the uniform liquid state means that the portion where the solid content concentration is locally different from other portions such as precipitation, phase separation or skinning is not found in the aqueous dispersion. Say.

  Moreover, it is preferable that coarse particles are not contained in the polyester-based aqueous dispersion immediately after preparation. Here, the coarse particles are specifically, when the polyester aqueous dispersion is subjected to pressure filtration (air pressure 0.2 MPa) with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) on the filter. These are particles that remain, and the above-described filtration or the like may be performed during the production process for the purpose of preventing coarse particles from being mixed into the polyester-based aqueous dispersion.

  Next, a method for using the aqueous dispersion obtained by removing the organic solvent from the polyester-based aqueous dispersion of the present invention will be described. This polyester-based aqueous dispersion is uniformly coated on the surface of various substrates by known film forming methods such as dipping method, brush coating method, spray coating method, curtain flow coating method, etc. After that, a uniform resin film can be formed in close contact with the surfaces of various substrates by performing drying or heat treatment for drying and baking.

  As the heat treatment apparatus at this time, a normal hot air circulation type oven, an infrared heater, or the like may be used. In addition, the heating temperature and the heating time are appropriately selected depending on the characteristics of the base material to be coated, the type of the curing agent described later, and the blending amount. The heating time is preferably from 160 seconds to 5 minutes. In addition, when the precipitation and deposit have arisen in the polyester-type aqueous dispersion before use, it is preferable to use in the state from which these were removed.

  The thickness of the resin coating formed using the polyester-based aqueous dispersion is appropriately selected depending on the application, but is particularly preferably 0.5 to 25 μm. If the film is formed so that the thickness of the resin film falls within the above range, a resin film having excellent uniformity can be obtained. In addition, in order to adjust the thickness of the resin coating, in addition to appropriately selecting an apparatus used for coating and its use conditions, a polyester-based aqueous dispersion having a concentration suitable for the desired thickness of the resin coating is used. It is preferable to use it. The concentration at this time can be adjusted by the charged composition at the time of preparation. Moreover, you may prepare by diluting the polyester-type aqueous dispersion once prepared suitably.

  The above-mentioned polyester-based aqueous dispersion can be used as it is, but by further baking and curing the polyester-based aqueous dispersion obtained by blending a curing agent, high film performance, that is, superior workability, water resistance Performance and solvent resistance can be exhibited.

  The curing agent is not particularly limited as long as it is a functional group possessed by a polyester resin, for example, a carboxyl group or a hydroxyl group, particularly a curing agent having reactivity with a carboxyl group, such as urea resin, melamine resin, benzoguanamine resin, etc. Examples thereof include amino resins, polyfunctional epoxy compounds, polyfunctional isocyanate compounds and various block isocyanate compounds thereof, polyfunctional aziridine compounds, carbodiimide group-containing compounds, oxazoline group-containing polymers, and phenol resins. One of them may be used or two or more may be used in combination. Among the curing agents described above, amino resins, particularly melamine resins, polyfunctional epoxy compounds, polyfunctional isocyanate compounds and their various blocked isocyanate compounds, oxazoline group-containing polymers and carbodiimide group-containing compounds are excellent in reactivity with polyester resins. This is preferable. Among these, when a melamine resin is used, a resin film having particularly excellent solvent resistance can be formed.

Melamine resin is a general term for melamine and formaldehyde addition-condensed. Furthermore, alcohol (ROH) is further subjected to addition-condensation, so that the amino group of melamine remains (1) as it is (-NH ₂ ), (2) iminomethylol group (—NHCH ₂ OH), (3) iminoalkyl ether group (—NHCH ₂ OR), (4) dimethylolamino group (—n (CH ₂ OH) ₂ ), (5) partial alkyl Etherified dimethylolamino group (—N (CH ₂ OH) CH ₂ OR), (6) Fully alkyletherified dimethylolamino group (—N (CH ₂ OR ₂ )) (1)-(6) is a compound containing complex and various structures condensed to a high molecular weight.

  The average degree of polymerization of the melamine resin used for the curing agent is most preferably 1.1 to 3.0. Examples of such a melamine resin include a Cymel series such as “Cymel 325, Cymel 303, Cymel 370” manufactured by Mitsui Cytec Co., Ltd., or a My Coat series such as “My Coat 212”.

  If necessary, an acid catalyst such as p-toluenesulfonic acid or dodecylbenzenesulfonic acid blocked with an organic amine compound may be added to the polyester-based aqueous dispersion obtained by blending the melamine resin.

  Next, glycidyl ether type, glycidyl ester type, glycidyl amine type and the like are generally known as polyfunctional epoxy compounds used for curing agents. The epoxy compound to be used is not particularly limited, but when a compound having 3 or more epoxy groups is used, water resistance, solvent resistance and workability can be improved.

  Among polyfunctional epoxy compounds, those having an aromatic ring such as a benzene ring or a naphthalene ring, a cyclic aliphatic ring such as a cyclohexane ring, a heterocyclic ring such as a triazine ring in the molecular structure, particularly an aromatic ring , Workability can be further improved. Examples of polyfunctional epoxy compounds having an aromatic ring include epoxy resins such as bisphenol A type, bisphenol F type, bisphenol AD type, bisphenol S type, tetrabromobisphenol A type, cresol novolak type, phenol novolak type, etc. Is generally known.

  Among polyfunctional epoxy compounds, in particular, polyfunctional epoxy compounds having aromaticity have a softening point of 60 measured by the ring and ball method described in JIS K-7234 from the viewpoint of the balance between heat resistance and workability. Those having a temperature of ˜100 ° C. are preferred. For example, “Denacol EM-150, Denacast EM-101, Denacast EM-103” manufactured by Nagase Chemical Industries, Ltd. can be suitably used.

  The aqueous dispersion obtained by blending the polyfunctional epoxy compound may be blended with a curing catalyst as necessary. As the curing catalyst, a primary amine, a secondary amine, a tertiary amine, and various polyamines thereof. And imidazoles. Specifically, triethylenediamine is used as a tertiary amine, and 2-methylimidazoles are used as imidazoles. These are particularly effective in promoting the reaction between the carboxyl group in the polyester resin or its anhydride and the polyfunctional epoxy compound.

  Moreover, the polyfunctional isocyanate compound used for the curing agent has two or more isocyanate groups in one molecule. By having three or more isocyanate groups, water resistance, solvent resistance, and workability can be further improved. it can. Examples of the blocked isocyanate compound include those in which a part or all of the isocyanate group of the polyfunctional isocyanate compound is stabilized with a known blocking agent such as caprolactam, phenol, oxime, or organic amine.

  As the polyfunctional isocyanate compound, for example, “Baihijoru 3100, Death Module N3400, Death Module DN” manufactured by Sumitomo Bayer Urethane Co., Ltd. “Takenate WD720, Takenate WD725, Takenate WD730” manufactured by Mitsui Takeda Chemical Co., Ltd., “Duranate WB40- 100, Duranate WB40-80D, Duranate WX-1741 ”and the like. Examples of blocked isocyanates include “Baihijoule BL5140, Bihijoule BL5235” manufactured by Sumitomo Bayer Urethane Co., Ltd., “Elastotron BN-69, Elastotron BN77, Elastolone BN-27, Elastolone BN-04”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. “Takenate WB-700, Takenate WB-720, Takenate WB-730, Takenate WB-920, Takenate XWB-72-K55” and the like.

  The polyester-based aqueous dispersion obtained by blending the polyfunctional isocyanate compound and its various blocked isocyanate compounds may be blended with a curing catalyst as necessary. As the curing catalyst, di-n-butyltin dilaurate, Examples thereof include tin-based curing catalysts such as tetra-n-butyltin and tetramethylbutanediamine.

  Furthermore, the multi-antagonized oxazoline group-containing polymer used for the curing agent can be easily obtained by polymerizing a monomer composition containing an oxazoline derivative, as described in, for example, JP-A-9-328656. Examples of such oxazoline derivatives include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, and 2-isopropenyl-2-oxazoline. 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline. The monomer other than the oxazoline derivative contained in the monomer composition containing the oxazoline derivative is not particularly limited as long as it is a compound that is copolymerized with the oxazoline derivative and is inert to the oxazoline group. . In the oxazoline group-containing copolymer, the proportion of the structural unit derived from the oxazoline derivative is preferably 5% by mass or more.

  Examples of the oxazoline group-containing polymer include “Epocross WS-500, Epocross WS-700, Epocross K1010E, Epocross K1020E, Epocross K1030E, Epocross K2010E, Epocross K2020E, Epocross K2030E” manufactured by Nippon Shokubai Co., Ltd.

  Moreover, the carbodiimide group containing compound used for a hardening | curing agent is a compound which has 1 or more carbodiimide group (-N = C = N-) in 1 molecule, and is marketed normally as a polymer which has 2 or more carbodiimide groups. Has been. Examples include “Carbodilite E-01, Carbodilite E-02, Carbodilite V-02, Carbodilite V-02-L2, Carbodilite V-04, Carbodilite V-06” manufactured by Nisshinbo Co., Ltd.

  The blending amount of the curing agent is not particularly limited as long as the curing of the polyester resin is achieved, but does not impair the adhesion to various substrates and processing, etc., possessed by the polyester aqueous dispersion resin. From this viewpoint, the mass ratio (nonvolatile content ratio) of the polyester-based aqueous dispersion resin and the curing agent in the polyester-based aqueous dispersion is preferably: polyester-based aqueous dispersion resin: curing agent = 95: 5-75: 25 is preferred. Moreover, when mix | blending 2 or more types of hardening | curing agents, those total compounding quantities should just be in the said range.

  Further, the curing temperature and the curing time depend on the type of curing agent and the thickness of the resin film to be formed, and thus cannot be defined unconditionally. However, the normal curing temperature is 80 to 250 ° C. and the curing time is 10 hours. Second to about 30 minutes.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these. In addition, each characteristic in an Example was evaluated by the following method.
(1) Acid value 0.5 g of a polyester-based aqueous dispersion resin is dissolved in 50 ml of a mixed solvent of dioxane / distilled water = 10/1 (mass ratio), heated to reflux, and then 0.1 × 10 ³ mol / L. It was determined by titration with a potassium hydroxide methanol solution.
(2) Hydroxyl value 3 g of resin is dissolved in 50 ml of pyridine, acetylated by adding 5 ml of acetylated solution consisting of 6 ml of acetic anhydride and 44 ml of pyridine, and titrated with 0.5 N potassium hydroxide methanol solution. It was.
(3) Color tone Using a color difference meter ND-Sigma 80 manufactured by Nippon Denka Kogyo Co., Ltd., the b value of a Hunter Lab colorimeter was determined and evaluated.

  The smaller the b value, the better the yellow value as the value increases, so long as it does not become extremely small.

  A: The b value was less than 15.0.

X: The b value was 15.0 or more.
(4) State of aqueous dispersion ○: No layer separation or precipitation occurred.

X: Layer separation or precipitation occurred.
(5) Adhesion
According to JIS K 5400, the coated plate was immersed in boiling water for 2 hours and then air-dried at room temperature for 24 hours. Thereafter, the coating film was cut into a grid pattern with a cutter knife, and a peeling test with an adhesive tape was performed. The peeled state was evaluated in two stages.

  ○: No peeling is observed at the interface between the coating film and the material.

  X: Peeling is recognized partially or entirely at the interface between the coating film and the material.

(Example 1)
9.35 kmol (1554 kg) of terephthalic acid, 3.34 kmol (555 kg) of isophthalic acid, 0.53 kmol (78 kg) of adipic acid, mixed water 10 wt% neopentyl glycol 6.41 kmol (742 kg), ethylene glycol 6.94 kmol (431 kg) In an esterification reaction tank, and esterification was performed at a pressure of 0.3 MPa and a temperature of 260 ° C. for 4 hours. After the obtained esterified product is transferred to a polycondensation reaction tank, it is composed of aluminum hydroxide, magnesium hydroxide and magnesium carbonate as a polycondensation catalyst, and a solid solution (molar ratio of aluminum / magnesium of 0.4) 40 kg of ethylene glycol slurry (concentration of HT-P manufactured by Sakai Chemical Industry Co., Ltd.) adjusted to 1.5% by mass (the content of the solid solution is 200 ppm with respect to the polyester aqueous dispersion resin) to 0.5 hPa Under reduced pressure, a polycondensation reaction was performed at 280 ° C. for 4 hours to obtain a polyester-based aqueous dispersion resin having an intrinsic viscosity of 0.45 dl / g and a high polymerization degree. Next, 1.071 kmol (178 kg) of isophthalic acid was added, depolymerization was performed at 250 ° C. for 2 hours under normal pressure, and then the solution was discharged.

  Next, using a stirrer “Special Machine Industries Co., Ltd., TK Robotics” equipped with a jacketed 2 L glass container with a jacket, 300 g of the obtained polyester resin, 180 g of isopropyl alcohol, 24 g of triethylamine, 496 g of When distilled water was charged into a glass container and stirred at a rotational speed of a stirrer (homodisper) of 7000 rpm, no precipitation of resin particulates was observed at the bottom of the container, confirming that it was in a completely floating state. Therefore, while maintaining this state, hot water was passed through the jacket after 10 minutes. Then, the system temperature was maintained at 73 to 75 ° C., and further stirred for 30 minutes. Thereafter, cold water was allowed to flow through the jacket, and the rotational speed was lowered to 4000 rpm, followed by cooling to room temperature (about 25 ° C.) while stirring to obtain a milky white uniform polyester-based aqueous dispersion.

Using this aqueous dispersion, spray coating was performed on a zinc phosphate-treated steel sheet so that the film pressure was 15 μm, and baking was performed at 130 ° C. for 5 minutes.
(Examples 2, 4, and 5)
A polyester aqueous dispersion resin was obtained in the same manner as in Example 1 except that the charging composition and the addition amount of the polymerization catalyst were changed as shown in Table 1. Subsequently, using the obtained polyester-based aqueous dispersion resin, a polyester-based aqueous dispersion was obtained at a blending ratio shown in Table 1.
(Example 3)
A polyester aqueous dispersion resin was obtained in the same manner as in Example 1 except that the charging composition and the addition amount of the polymerization catalyst were changed as shown in Table 1. Furthermore, 0.4992 kmol (52 kg) of neopentyl glycol was added to the obtained polyester-based aqueous dispersion resin, depolymerization was performed at 270 ° C. for 1 hour at normal pressure, and then 0.3283 kmol (69 kg) of trimellitic acid. ) Was added, and depolymerization was performed at 250 ° C. for 2 hours at normal pressure to obtain a polyester-based aqueous dispersion resin as shown in Table 1.

Subsequently, using the obtained polyester-based aqueous dispersion resin, a polyester-based aqueous dispersion was obtained at a blending ratio shown in Table 1.
(Comparative Examples 1-5)
A polyester aqueous dispersion resin was obtained in the same manner as in Example 1 except that the charging composition and the addition amount of the polymerization catalyst were changed as shown in Table 1. Subsequently, using the obtained polyester-based aqueous dispersion resin, a polyester-based aqueous dispersion was obtained at a blending ratio shown in Table 1.

 Table 1 shows the performance of the coating films obtained in Examples 1 to 5 and Comparative Examples 1 to 5 together.

As is apparent from Table 1, the color tone of the polyester-based aqueous dispersion resin obtained in Examples 1 to 5 is good, and the polyester-based aqueous dispersion using this resin is adhesive to the steel plate. The film properties such as impact resistance and smoothness were good.

  On the other hand, in Comparative Example 1, the acid value of the polyester-based aqueous dispersion resin was high, and the impact resistance and adhesion of the coating film were inferior.

  In Comparative Example 2, the acid value of the polyester-based aqueous dispersion resin was low, precipitation and layer separation occurred after the polyester-based aqueous dispersion was prepared, and the coating film could not be evaluated.

  In Comparative Example 3, the hydroxyl group value of the polyester-based aqueous dispersion resin was high, and the adhesion of the coating film was poor.

  In Comparative Example 4, since the amount of the polymerization catalyst added was large during the production of the polyester-based aqueous dispersion resin, the color tone of the obtained resin was poor.

In Comparative Example 5, since the amount of the polymerization catalyst added was small during the production of the polyester-based aqueous dispersion resin, the degree of polymerization did not increase, and the reaction was stopped midway.

Claims (3)

  A polyester mainly composed of an aromatic dicarboxylic acid component and a glycol component, having an acid value of 3 to 40 mg KOH / g, a hydroxyl value of 20 mg KOH / g or less, and containing 100 to 400 ppm of a solid solution composed of a magnesium compound and an aluminum compound A polyester-based aqueous dispersion resin.   A magnesium compound and an aluminum compound are used as a polymerization catalyst in the production of a polyester-based aqueous dispersion resin mainly composed of an aromatic dicarboxylic acid component and a glycol component and having an acid value of 3 to 40 mg KOH / g and a hydroxyl value of 20 mg KOH / g or less. A method for producing a resin for an aqueous polyester-based dispersion, comprising adding 100 to 400 ppm of a solid solution comprising: A polyester-based aqueous dispersion obtained by dispersing or dissolving the polyester-based aqueous dispersion resin according to claim 1 in an aqueous medium.