JPWO2014171402A1 - Polyester resin and water dispersion using the same - Google Patents

Abstract

The present invention is a polyester resin comprising a carboxylic acid component and an alcohol component, and when the total carboxylic acid component is 100 mol% and the total alcohol component is 100 mol%, (A) a dicarboxylic acid component having no sulfonate group 50 to 100 mol%, (B) 50 to 100 mol% of a glycol component having no sulfonate group, (C) 3 to 30 mol% of a sulfonate group-containing monomer component having one ester-reactive functional group, And (D) a polyester resin containing 1 to 20 mol% of a compound component having three or more functional groups, and the amount ratio of the component (C) and the component (D) is in a specific range, and can be dispersed in water. Even when an ionic group is introduced to such an extent, it is a polyester resin having excellent water resistance.

Description

  The present invention relates to a polyester resin excellent in water resistance imparted with ionicity and an aqueous dispersion of the polyester resin.

  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 dispersing or solubilizing a polyester resin in water, a method of copolymerizing a hydrophilic raw material and introducing it into a molecular skeleton, for example, a raw material containing a sulfonic acid metal base, a polyalkylene glycol or an aliphatic carboxylic acid A method of copolymerizing these alone or in combination is known. However, in either 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. It was.

  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, it will not be practical unless the problem of satisfying the contradictory performance of hydrophilicity and water resistance is overcome.

  In addition, as shown in Patent Document 2, 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-A-7-188423

  The present invention has been made to solve the above-described problems of the conventional technology. That is, the present invention can provide a polyester resin excellent in water resistance even when an ionic group is introduced to such an extent that it can be dispersed in water.

  The present inventor examined the above factors, and as a result, copolymerized a component having two or more ester-reactive functional groups represented by dimethyl 5-sodium sulfoisophthalate. It was found that the resin contained was inferior in water resistance. Further, in order to improve the dispersibility in water, it is useful to increase the copolymerization amount of the sulfonic acid metal base, but an ester-reactive functional group represented by dimethyl 5-sodium sulfoisophthalate. It has been found that a resin containing a sulfonic acid metal base in a polymer chain obtained by copolymerizing a component having two or more has a high melt viscosity of the resin and the amount of copolymerization is limited. Accordingly, the present inventor has conducted extensive studies to solve the above problems, and as a result, the sulfonate group-containing monomer having one ester-reactive functional group and the compound having three or more functional groups are used in combination. A method for introducing a sulfonate group at the terminal was found, and the resin was found to be water-dispersible. In this method, it has been found that the melt viscosity of the resin becomes too high and the amount of copolymerization of the sulfonate group-containing compound is not limited.

The present invention is as follows.
[1] A polyester resin composed of a carboxylic acid component and an alcohol component, and when the total carboxylic acid component is 100 mol% and the total alcohol component is 100 mol%, (A) a dicarboxylic acid component having no sulfonate group 50 to 100 mol%, (B) 50 to 100 mol% of a glycol component having no sulfonate group, (C) a carboxylic acid component (C1) represented by the following (formula 1), and the following (formula 2) 3 to 30 mol% of a compound component containing at least one sulfonate group selected from the group consisting of the alcohol component (C2) represented by (wherein (C1) is based on 100 mol% of all carboxylic acid components) (C2) is based on 100 mol% of all alcohol components), and (D) a carboxylic acid component having three or more functional groups (D1) and an alcohol component having three or more functional groups. 1 to 20 mol% of at least one compound component selected from the group consisting of (D2) (provided that (D1) is 100 mol% of all carboxylic acid components and (D2) is 100 mol% of all alcohol components. And a polyester resin characterized by satisfying the following formula (I):

[In formula (1), X ¹ represents a divalent aromatic group having 6 to 20 carbon atoms or an alkylene group having 1 to 8 carbon atoms, and M ⁺ represents a metal ion, a tetraalkylphosphonium ion or a tetraalkylammonium ion. Represents. ]

[In the formula (2), X ² represents a divalent aromatic group having 6 to 20 carbon atoms or an alkylene group having 1 to 8 carbon atoms, and M ⁺ represents a metal ion, a tetraalkylphosphonium ion or a tetraalkylammonium ion. Represents. ]
(C1 + C2) / (D1 + D2) = 1.5 to 7.0 Formula (I)
[C1 and C2 represent the content (mol%) of the component (C1) and the content (mol%) of the component (C2), respectively, and D1 and D2 represent the content (mol%) of the component (D1), respectively. , (D2) represents the content (mol%) of the component. ]

[2] (C1) is a carboxylic acid component represented by the following (formula 3), (C2) is an alcohol component represented by the following (formula 4), (D1) is trimellitic acid, (D2 ) Is trimethylolpropane. The polyester resin according to claim 1.

[3] The polyester resin according to [1] or [2], wherein the component (A) is an aromatic dicarboxylic acid.
[4] The polyester resin according to [3], wherein the aromatic dicarboxylic acid is at least one selected from 2,6-naphthalenedicarboxylic acid and terephthalic acid.
[5] An aqueous dispersion using the polyester resin according to any one of [1] to [4].

  The polyester resin of the present invention is excellent in water resistance. Therefore, application to a member exposed for a long time under high temperature and high humidity such as outdoors is useful.

It is the chart which measured the polyester resin obtained in the Example of this invention with the nuclear magnetic resonance apparatus.

  In order to improve the water resistance, it is important not to contain a sulfonate group in the resin chain (site not at the end of the polymer chain). However, it is essential to impart ionicity in consideration of water dispersion.

The polyester resin of the present invention is obtained by using a sulfonate group-containing monomer having one ester-reactive functional group (component (C)) and a compound having three or more functional groups (component (D)). It is characterized by containing a sulfonate group at the terminal. Hereinafter, unless otherwise specified, the mol% representing the copolymerization amount is that when the polyester resin is composed of a carboxylic acid component and an alcohol component, the total carboxylic acid component is 100 mol%, and the total alcohol component is 100 mol%. Represents mol%. Using at least one compound component selected from the group consisting of a carboxylic acid component (D1) having three or more functional groups and an alcohol component (D2) having three or more functional groups, (Formula 1) Since the carboxylic acid component (C1) and / or the alcohol component (C2) represented by (Formula 2) is used, the total amount of carboxylic acid components (mol%) constituting the polyester resin of the present invention And the total alcohol content (mol%) may not be the same. The total carboxylic acid component amount (mol%) / total alcohol component amount (mol%) is preferably in the range of 0.55 to 1.80.
Using at least one compound component selected from the group consisting of a carboxylic acid component (D1) having three or more functional groups and an alcohol component (D2) having three or more functional groups, (Formula 1) When the carboxylic acid component (C1) represented is used, the total carboxylic acid component amount (mol%) and the total alcohol component amount (mol%) constituting the polyester resin of the present invention are not the same. Since the carboxylic acid component (C1) represented by (Formula 1) is present at the terminal, the total carboxylic acid component amount (mol%) / total alcohol component amount (mol%) exceeds 1. In this case, the total carboxylic acid component amount (mol%) / total alcohol component amount (mol%) is preferably in the range of 1.20 to 1.60.

  The sulfonate group-containing monomer having one ester-reactive functional group acts as a terminal blocking agent, and thus depends on the degree of polymerization of the resulting polymer. However, when used alone, it is usually 2 mol% (total carboxylic acid component 100 Only about the degree of copolymerization (with respect to 100% by mol or 100% by mol of all alcohol components) can be copolymerized, and this amount of copolymerization cannot be dispersed in water. In the case of a linear molecule, if it is attempted to copolymerize more than 2 mol%, it does not have a polymer terminal to react, so it exists as an unreacted substance and exists as a foreign substance (monomer) in the resin.

  Therefore, in order to disperse in water, use a sulfonate group-containing monomer having one ester-reactive functional group (component (C)) and a compound having three or more functional groups (component (D)). is important. A compound having three or more functional groups increases the number of reactive resin ends that branch the resin, resulting in an increase in sulfonate group-containing monomers having one ester-reactive functional group copolymerized at the resin end. Enables water dispersion.

The carboxylic acid component (C1) represented by the following (formula 1) of the component (C) will be described.
As the carboxylic acid component of (Formula 1), not only a carboxylic acid compound but also an alkyl ester compound having 1 to 6 carbon atoms can be used as a raw material. There is no particular limitation as long as it has one ester-reactive functional group and one or more sulfonate groups in the molecule, but in formula (1), X ¹ is a divalent aromatic group having 6 to 10 carbon atoms. Among them, a divalent benzene ring is more preferable, or an alkylene group having 2 to 6 carbon atoms is preferable. M ⁺ is preferably a metal ion, more preferably a sodium ion, a potassium ion, or a lithium ion, and even more preferably a sodium ion. Specifically, sodium m-sulfobenzoate, potassium m-sulfobenzoate, lithium m-sulfobenzoate, tetramethylammonium m-sulfobenzoate, tetramethylphosphonium m-sulfobenzoate, m-carboxymethyl-benzene Sodium sulfonate, potassium m-carboxymethyl-benzenesulfonate, lithium m-carboxymethyl-benzenesulfonate, sodium o-sulfobenzoate, potassium o-sulfobenzoate, lithium o-sulfobenzoate, o-carboxymethyl- Sodium benzenesulfonate, potassium o-carboxymethyl-benzenesulfonate, lithium o-carboxymethyl-benzenesulfonate, sodium p-sulfobenzoate, potassium p-sulfobenzoate, lithium p-sulfobenzoate, p- Tetramethylammonium benzoate, tetramethylphosphonium p-sulfobenzoate, sodium p-carboxymethyl-benzenesulfonate, potassium p-carboxymethyl-benzenesulfonate, lithium p-carboxymethyl-benzenesulfonate, 2-carboxy- Sodium 6-naphthalenesulfonate, potassium 2-carboxy-6-naphthalenesulfonate, lithium 2-carboxy-6-naphthalenesulfonate, sodium 2-carboxymethyl-6-naphthalenesulfonate, 2-carboxymethyl-6-naphthalenesulfone Acid potassium, lithium 2-carboxymethyl-6-naphthalenesulfonate, tetramethylammonium 2-carboxymethyl-6-naphthalenesulfonate, 2-carboxymethyl-6-naphthalene Tetramethylphosphonium sulfonate, sodium 1-carboxy-3-propanesulfonate, sodium 1-carboxy-4-butanesulfonate, sodium 1-carboxy-5-pentanesulfonate, sodium 1-carboxy-6-hexanesulfonate, Examples include sodium 1-carboxy-7-heptanesulfonate and sodium 1-carboxy-8-octanesulfonate. Sodium m-sulfobenzoate, sodium o-sulfobenzoate and sodium p-sulfobenzoate are preferred, and sodium m-sulfobenzoate is most preferred.

[In formula (1), X ¹ represents a divalent aromatic group having 6 to 20 carbon atoms or an alkylene group having 1 to 8 carbon atoms, and M ⁺ represents a metal ion, a tetraalkylphosphonium ion or a tetraalkylammonium ion. Represents. ]

The alcohol component (C2) represented by the following (formula 2) of the component (C) will be described.
As the alcohol component of (Formula 2), not only an alcohol compound but also an amine compound or a thiol compound which is a nucleophilic attack functional group capable of reacting with an ester can be used as a raw material. Moreover, the compound whose hydroxyl group part is an acetoxy group, an epoxy group, and the hydrogen of a hydroxyl group is a C2-C6 alkyl group can also be used as a raw material. There is no particular limitation as long as it has one ester-reactive functional group and one or more sulfonate groups in the molecule, but in formula (2), X ¹ is a divalent aromatic group having 6 to 10 carbon atoms. Among them, a divalent benzene ring is more preferable, or an alkylene group having 2 to 8 carbon atoms is preferable. M ⁺ is preferably a metal ion, more preferably a sodium ion, a potassium ion, or a lithium ion, and even more preferably a sodium ion. Specifically, sodium isethionate, potassium isethionate, lithium isethionate, tetramethylammonium isethionate, tetramethylphosphonium isethionate, sodium 1-hydroxyethanesulfonate, potassium 1-hydroxyethanesulfonate, 1-hydroxyethanesulfone Lithium acid, tetramethylammonium 1-hydroxyethanesulfonate, tetramethylphosphonium 1-hydroxyethanesulfonate, sodium 1-hydroxypropanesulfonate, sodium 1-hydroxybutanesulfonate, sodium 1-hydroxypentanesulfonate, 1-hydroxy Sodium hexanesulfonate, sodium 1-hydroxyheptanesulfonate, sodium 1-hydroxyoctanesulfonate, 4-aminoben Sodium Nsuruhon acid, sodium 2-mercapto ethanesulfonic acid, 4-acetoxy-1-sodium butane sulfonate include oxiranyl sodium methanesulfonate. Sodium isethionate and sodium 1-hydroxyethanesulfonate are preferred, and sodium isethionate is most preferred.
The fact that the component (C) is copolymerized with the polyester resin can be analyzed with a nuclear magnetic resonance apparatus.

[In the formula (2), X ² represents a divalent aromatic group having 6 to 20 carbon atoms or an alkylene group having 1 to 8 carbon atoms, and M ⁺ represents a metal ion, a tetraalkylphosphonium ion or a tetraalkylammonium ion. Represents. ]

The carboxylic acid component (D1) having three or more functional groups as the component (D) and the alcohol component (D2) will be described.
The compound having three or more functional groups is not particularly limited as long as it has three or more ester-reactive functional groups in the molecule. Specifically, as the trifunctional or more functional carboxylic acid component (D1), Examples thereof include aromatic carboxylic acids such as trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid and trimesic acid, and aliphatic carboxylic acids such as 1,2,3,4-butanetetracarboxylic acid. These tri- or higher functional carboxylic acid components can be used not only as carboxylic acid compounds, but also as C1-6 alkyl ester compounds and acid anhydride compounds as raw materials. For example, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride and the like can be used.
Examples of the tri- or higher functional alcohol component (D2) include glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, α-methylglucose, mannitol, and sorbitol.
(D1) is preferably trimellitic acid, and (D2) is preferably trimethylolpropane. As the raw material used as the component (D), trimellitic anhydride and trimethylolpropane are preferable.
The fact that a compound having three or more functional groups is copolymerized on the polyester resin can be analyzed by a nuclear magnetic resonance apparatus.

In order to enable water dispersion of the resin, it is necessary to copolymerize 3 to 30 mol% of a sulfonate group-containing monomer having one ester-reactive functional group of component (C). When the copolymerization amount is less than 3 mol%, it cannot be dispersed in water. If the copolymerization amount exceeds 30 mol%, the copolymerization amount of three or more functional groups also increases, the melt viscosity becomes too high, and gelation may be induced. The lower limit of the amount of copolymerization of component (C) is preferably 5 mol%, more preferably 8 mol%. The upper limit of the amount of copolymerization of component (C) is preferably 25 mol%, more preferably 22 mol%.
In addition, since (C1) considers the amount of copolymerization with respect to 100 mol% of all carboxylic acid components and (C2) with respect to 100 mol% of all alcohol components, for example, (C1) is 100 mol% of all carboxylic acid components. When (C2) is copolymerized to 10 mol% with respect to 100 mol% of all alcohol components, the copolymerization amount of component (C) is considered to be 20 mol%.

In order to secure a sulfonate group-containing monomer having one ester-reactive functional group capable of being dispersed in water, 1 to 20 mol% of a compound having three or more functional groups as component (D) is copolymerized. is necessary. When the copolymerization amount is less than 1 mol%, it is possible to copolymerize only less than 3 mol% of the sulfonate group-containing monomer having one ester-reactive functional group necessary for water dispersion. If the copolymerization amount exceeds 20 mol%, gelation may be induced even in combination with a sulfonate group-containing monomer having one ester-reactive functional group. (D) Preferably the minimum of the copolymerization amount of a component is 2 mol%, More preferably, it is 3 mol%. (D) The upper limit of the copolymerization amount of component becomes like this. Preferably it is 15 mol%, More preferably, it is 10 mol%.
In addition, since (D1) considers the amount of copolymerization with respect to 100 mol% of all carboxylic acid components with respect to 100 mol% of all carboxylic acid components, for example, (D1) is 100 mol% of all carboxylic acid components. When 5 mol% is copolymerized with respect to 100 mol% of the total alcohol component and 5 mol% is copolymerized with respect to 100 mol% of the total alcohol component, the amount of copolymerization of component (D) is considered to be 10 mol%.

Usually, when the amount of copolymerization of a compound having three or more functional groups is increased, gelation occurs due to three-dimensional crosslinking. However, the gel point is blocked by using together with a sulfonate group-containing monomer having one ester-reactive functional group that acts as a terminal blocking agent. In order to avoid gelation, [(C) component: sulfonate group-containing monomer copolymerization amount (mol%) having one ester-reactive functional group] / [(D) component: three or more functional groups It is important that the amount of copolymerization (mol%) of the compound having a value satisfies a ratio (copolymerization ratio) of 1.5 to 7.0. When the copolymerization ratio is less than 1.5, the amount of copolymerization of the compound having three or more functional groups is large, and the gel point is set by the end capping effect of the sulfonate group-containing monomer having one ester-reactive functional group. There is a risk of gelation due to failure to seal. When the copolymerization ratio is greater than 7.0, the amount of copolymerization of the compound having three or more functional groups is small, and the sulfonate group-containing monomer having one ester-reactive functional group is copolymerized to an amount capable of being dispersed in water. It cannot be polymerized. The lower limit of the copolymerization ratio is more preferably 1.8, particularly preferably 2.0, and the upper limit is more preferably 6.0, and particularly preferably 5.0.
The copolymerization ratio can also be expressed as in formula (I).
(C1 + C2) / (D1 + D2) = 1.5 to 7.0 Formula (I)
[C1 and C2 represent the content (mol%) of the component (C1) and the content (mol%) of the component (C2), respectively, and D1 and D2 represent the content (mol%) of the component (D1), respectively. , (D2) represents the content (mol%) of the component. ]

  The polyester of the present invention is a resin composed of a carboxylic acid component and an alcohol component, and is a polyhydric alcohol containing one or more selected from polycarboxylic acids containing dicarboxylic acids and ester-forming derivatives thereof and glycol. One consisting of one or two or more selected from the above, one consisting of a hydroxycarboxylic acid and an ester-forming derivative thereof, or one consisting of a cyclic ester.

The dicarboxylic acid component having no sulfonate group as the component (A) will be described. As the dicarboxylic acid component, not only dicarboxylic acid but also an alkyl ester compound having 1 to 6 carbon atoms (dialkyl ester compound) can be used as a raw material.
The aliphatic dicarboxylic acid having no sulfonate group is not particularly limited. Specifically, oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, Aliphatic dicarboxylic acids such as octadecanedioic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid and the like can be mentioned. Adipic acid, azelaic acid and sebacic acid are preferred, and adipic acid is most preferred. It can be analyzed with a nuclear magnetic resonance apparatus that the polyester resin contains a dicarboxylic acid having no sulfonate group. From the viewpoint of water resistance, the aliphatic dicarboxylic acid is preferably 20 mol% or less with respect to the total dicarboxylic acid component, and it is particularly preferable not to use the aliphatic dicarboxylic acid.

The aromatic dicarboxylic acid having no sulfonate group is not particularly limited, and specific examples include terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, and 4,4′-dicarboxybiphenyl. Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornenedicarboxylic acid, and tetrahydrophthalic acid. From the viewpoint of water resistance, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid are preferable, and naphthalenedicarboxylic acid and terephthalic acid are most preferable. The naphthalenedicarboxylic acid is preferably 2,6-naphthalenedicarboxylic acid.
The amount of copolymerization of component (A) is 50 to 100 mol%, but depending on the amount of copolymerization of the carboxylic acid component as component (C) and / or component (D), the component (A) is preferred. The upper limit and the lower limit of the copolymerization amount are changed so that the total carboxylic acid components constituting the polyester resin are 100 mol%. For example, when (C1) is copolymerized in an amount of 3 to 30 mol%, the copolymerization amount of component (A) is preferably 70 to 97 mol%, and (D1) is copolymerized in an amount of 1 to 20 mol%, The copolymerization amount of component A) is preferably 80 to 99 mol%, and when (C1) is copolymerized 3 to 30 mol% and (D1) 1 to 20 mol%, the copolymerization amount of component (A) is 50-96 mol% is preferable. When neither (C1) nor (D1) is copolymerized, the amount of copolymerization of component (A) is preferably 100 mol%.

The glycol component having no sulfonate group (B) will be described.
The glycol having no sulfonate group is not particularly limited, and specific examples thereof include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, and 1,3-butane. Diol, 1,4-butanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, 2- Amino-2-methyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, neopentyl glycol, 3-methyl -1,5-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1, Nonanediol, 1,10-decanediol, 3 (4), 8 (9) -bis (hydroxymethyl) -tricyclo (5.2.2.1.2.6) decane, diethylene glycol, triethylene glycol, di Examples include aliphatic glycols such as propylene glycol, tripropylene glycol, polyethylene glycol, and polytetramethylene glycol. From the viewpoint of water dispersion, it is preferable to contain diethylene glycol, polyethylene glycol, or polytetramethylene glycol having an ether bond, and it is more preferable to use ethylene glycol, diethylene glycol, and polyethylene glycol in combination. The number average molecular weight of polyethylene glycol is preferably 500 to 4000, and the content is preferably 1 to 10 mol%. In addition, bisphenol A, bisphenol S, bisphenol C, bisphenol Z, bisphenol AP, ethylene oxide adduct or propylene oxide adduct of 4,4′-biphenol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, Examples thereof include alicyclic glycols such as 1,4-cyclohexanedimethanol.
The amount of copolymerization of the component (B) is 50 to 100 mol%, but depending on the amount of the alcohol component copolymerized as the component (C) and / or the component (D), the copolymerization of the component (B) is preferable. The upper limit and the lower limit of the polymerization amount change so that the total alcohol components constituting the polyester resin are 100 mol%. For example, when (C2) is copolymerized in an amount of 3 to 30 mol%, the copolymerization amount of component (B) is preferably 70 to 97 mol%, and (D2) is copolymerized in an amount of 1 to 20 mol%, The copolymerization amount of the component (B) is preferably 80 to 99 mol%. When (C2) is copolymerized to 3 to 30 mol% and (D2) is copolymerized to 1 to 20 mol%, the copolymerization amount of the component (B) is 50-96 mol% is preferable. When neither (C2) nor (D2) is copolymerized, the copolymerization amount of component (B) is preferably 100 mol%.

  In the polyester resin of the present invention, a hydroxycarboxylic acid compound may be used within a range of 30 mol% or less. At this time, half of the content is calculated as a carboxylic acid component and the other half is calculated as an alcohol component.

  In addition to the above, an ionic monomer having two or more ester-reactive functional groups represented by dimethyl 5-sodium sulfoisophthalate may be copolymerized if it is in a trace amount. From the viewpoint of water resistance, the ionic monomer having two or more ester-reactive functional groups is preferably 2 mol% or less (based on 100 mol% of all carboxylic acid components or 100 mol% of all alcohol components). It is particularly preferably 5 mol% or less.

  In addition to the above, a monocarboxylic acid or monoalcohol may be copolymerized if it is in a trace amount. From the viewpoint of water dispersibility, these components are preferably 2 mol% or less (relative to 100 mol% of all carboxylic acid components or 100 mol% of all alcohol components), and particularly preferably 1.5 mol% or less. preferable.

  From the viewpoint of water dispersion, the glass transition point of the resin is preferably 0 ° C to 70 ° C. The glass transition point of the resin is more preferably 20 ° C. to 70 ° C., further preferably 30 ° C. to 70 ° C., and particularly preferably 45 ° C. to 70 ° C. A resin having a glass transition point exceeding 70 ° C. has a high melt viscosity during water dispersion and is difficult to disperse in water, and a resin having a glass transition temperature of less than 0 ° C. may be difficult to handle in production.

Hereinafter, each step will be described.
In the esterification / exchange reaction, all monomer components and / or low polymers thereof are reacted by heating and melting under an inert atmosphere. The esterification / exchange temperature is preferably 180 to 250 ° C, more preferably 200 to 250 ° C. The reaction time is preferably 2.5 to 10 hours, and more preferably 4 to 6 hours. The reaction time is the time from the desired reaction temperature to the subsequent polycondensation reaction.

  In the polycondensation reaction, the glycol component is distilled off from the esterified product obtained by the esterification reaction at a temperature of 220 to 260 ° C. under reduced pressure, and the polycondensation reaction proceeds until a desired molecular weight is reached. The reaction temperature for the polycondensation is preferably 220 to 255 ° C, more preferably 220 to 250 ° C. The degree of vacuum is preferably 130 Pa or less. Insufficient pressure reduction is not preferable because the polycondensation time tends to be long. As the pressure reduction time until the pressure reaches 130 Pa or less from the atmospheric pressure, it is preferable to gradually reduce the pressure over 60 to 180 minutes.

  In the esterification / exchange reaction and polycondensation reaction, if necessary, polymerization is performed using an organic titanate compound such as tetrabutyl titanate, or an organic tin compound such as germanium dioxide, antimony oxide, or tin octylate. From the viewpoint of reaction activity, an organic titanate compound is preferable, and from the aspect of resin coloring, germanium dioxide is preferable.

  The reduced viscosity of the polyester resin used in the present invention is preferably 0.30 to 1.80 dl / g. When the reduced viscosity is less than 0.30 dl / g, even if water can be dispersed to some extent, problems such as aggregation and sedimentation of molecules having no hydrophilic group in the molecular chain over time occur. On the other hand, when it exceeds 1.80 dl / g, the cohesive force between the molecular chains in the resin is strong, and the hydrophilic group in the resin is prevented from moving to the water interface and coming into contact with water. May not be achieved. In particular, when the reduced viscosity is 0.32 to 0.75 dl / g, the effect of the present invention is maximized. The reduced viscosity 0.3 is about 3,000 in terms of number average molecular weight.

  Although the method to manufacture the aqueous dispersion of the polyester resin of this invention is not specifically limited, For example, the following method is mentioned. That is, an organic solvent (referred to as solvent A) in which the polyester resin can be dissolved or swollen and an organic solvent (referred to as solvent B) that becomes a poor solvent in which the polyester resin does not dissolve or swell as required 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 keeping the balance of seemingly contradictory effects of promoting the aggregation of the molecular chains by the solvent B while untangling the polyester molecular chains with the solvent 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.

  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 in the total polyester resin, preferably 0.5% or less, more preferably 0.2% or less, and still more preferably 0.01% or less. It is. If it exceeds 1%, a precipitate is generated with time, which may cause deterioration in storage stability or cause unevenness when used as a coating agent. In the copolymerized polyester resin of the present invention, a curing agent, various additives, pigments such as titanium oxide, zinc white, and carbon black, dyes, polyester resins, urethane resins, olefin resins, acrylic resins, alkyd resins, as necessary. A cellulose derivative etc. can be mix | blended.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples. Each value in the examples was determined by the following method.

(1) Reduced viscosity (ηsp / c)
0.05 g of a polyester resin was dissolved in 25 cm ³ of a mixed solvent of phenol / tetrachloroethane (mass ratio 6/4) and measured at 30 ° C. using an Ubbelohde viscosity tube.

(2) Polyester resin composition Determination of the composition and composition ratio of the polyester resin was performed by 1H-NMR measurement (proton nuclear magnetic resonance spectroscopy measurement) with a resonance frequency of 500 MHz. The measuring apparatus used was an NMR apparatus 500-MHz manufactured by VARIAN, and deuterated chloroform / deuterated hexafluoroisopropanol = 85/15 (weight ratio) was used as the solvent.

(3) Judgment of water dispersion possibility In a dispersion kettle equipped with a stirrer, a thermometer and a reflux condenser with 47 parts by mass of water and 18 parts by mass of isopropyl alcohol, maintained at an internal temperature of 30 ° C. Immediately after the completion of the polycondensation reaction, 35 parts by weight of molten polyester was added, and the mixture was stirred and dispersed in water while maintaining the system temperature at about 75 ° C., followed by cooling to obtain an aqueous dispersion.
The state of the obtained water dispersion was confirmed visually and judged as follows.
○: Water dispersion is transparent and water dispersion is possible ×: Water dispersion is opaque and water dispersion is impossible

(4) Water resistance evaluation 1
The polyester resin was freeze pulverized using a freezer mill (US specs 6750 type) containing liquid nitrogen to a powder of 20 mesh or less. 1 g of this powder was put into 100 ml of pure water, and it was stirred for 1 hour under conditions of heating and pressurizing at 130 ° C. in a closed system. The reduced viscosity of the sample before and after the hydrolysis test was measured by the method (1). From the measurement results obtained, (ΔHS reduced viscosity) = (reduced viscosity before hydrolysis test) − (reduced viscosity after hydrolysis test) was calculated.

(5) Water resistance evaluation 2
After the polyester resin was treated with Vacuum Drying Oven D41 made by Yamato Kagaku at 80 ° C. for 12 hours, 1 g of the resin was heated at 230 ° C. for 60 seconds using TABLE TYPE TEST PRESS SA-302-I made by Tester Sangyo Co., Ltd. The sample was pressed at 6.9 MPa for 90 seconds to obtain a sample having a thickness of 0.1 mm. The sample was cut into strips of 3 cm × 6 cm, the strip samples were suspended, and processed for 20 days under conditions of 85 ° C. and 85% RH using a table-type thermostatic chamber LH21-11M manufactured by Nagano Science Co., Ltd. The reduced viscosity of the sample before and after the moisture resistance test was measured by the method (1). From the obtained measurement results, (ΔMS reduced viscosity) = (reduced viscosity before the moisture resistance test) − (reduced viscosity before the moisture resistance test) was calculated.

(6) Glass transition temperature (Tg)
The copolyester resin vacuum-dried at room temperature was placed in an aluminum pan for a differential scanning calorimeter (DSC), heated at 250 ° C. for 1 minute, and then cooled with liquid nitrogen. The copolymer polyester resin pretreated as such was measured using DSC2920 manufactured by TA Instruments. Two samples derived from the glass transition in the obtained temperature rise curve observed in the middle of 5.0 mg of the sample, heated in the range of −10 to 150 ° C. at 10 ° C./min in a nitrogen atmosphere An intermediate value of the bending point temperature was determined and used as the glass transition temperature (Tg).

Example 1
In a 2 liter stainless steel autoclave with a stirrer, 187.8 g (0.77 mol) of dimethyl 2,6-naphthalenedicarboxylate, 91.9 g (0.47 mol) of dimethyl terephthalate, 35.1 g of trimellitic anhydride (0. 18 mol), sodium m-sulfobenzoate 90.1 (0.40 mol), polyethylene glycol # 2000 (number average molecular weight 2000) 76.7 g (0.038 mol), ethylene glycol 224.4 g (3.6 mol) ), 0.35 g of tetrabutyl titanate as a catalyst and 1 g of Irganox 1330 as a stabilizer were charged at 150 ° C., and the ester exchange reaction was performed for 220 minutes while raising the temperature to 220 ° C. to obtain an oligomer mixture. Thereafter, while raising the temperature to 240 ° C. over 60 minutes, the pressure of the reaction system was gradually lowered to 13.3 Pa (0.1 Torr), and a polyester polycondensation reaction was further performed at 240 ° C. and 13.3 Pa. . After releasing the pressure, the resin under slight pressure is discharged into cold water in a strand form, quenched, then held in cold water for 20 seconds, and then cut into a cylinder-shaped polyester resin pellet with a length of about 3 mm and a diameter of about 2 mm. Got. The properties of this polyester resin are shown in Table 1 with respect to the results of reduced viscosity, glass transition temperature, judgment of water dispersibility, and water resistance evaluation according to the above methods. In Table 1, each component is described by the name of the raw material used, and in the following composition analysis, each component is described by the name of the raw material used. The copolymerization amount of sodium m-sulfobenzoate, which is an ionic monomer, is large, and the water resistance evaluation 1 was not able to be evaluated because the polyester resin was dissolved in water. However, in the water resistance evaluation 2, the reduction in reduced viscosity was small and the water resistance was low. It was found that the property is excellent.

(Composition analysis)
The composition analysis was performed according to the method described above, and the composition was identified from the following peaks. When deuterated chloroform was adjusted to 7.33 ppm, the peak near 8.7 ppm (integral value; 10.0) to dimethyl 2,6-naphthalenedicarboxylate, and the peak near 8.1 ppm (integral value; 27.4) to terephthalate Dimethyl acid, peak near 7.8 ppm (integral value; 0.696) to trimellitic anhydride, peak near 7.6 ppm (integral value; 1.28) from sodium m-sulfobenzoate, around 4.8 ppm From the peak (integral value: 15.3) to ethylene glycol, the peak near 4.6 ppm (integral value; 10.4) to diethylene glycol, the peak near 3.7 ppm (integral value; 33.2) to polyethylene glycol # 2000 The composition ratio was identified. Diethylene glycol was by-produced by condensation of ethylene glycol and remained in the resin. The final composition was calculated as integral value / number of protons as follows, and carboxylic acid component / alcohol component (total carboxylic acid component amount (mol%) / total alcohol component amount (mol%)) was analyzed by the following method. . The NMR chart is shown in FIG.
(1) Sodium m-sulfobenzoate; 1.28 / 1 = 1.28
(2) trimellitic anhydride; 0.696 / 1 = 0.696
(3) Dimethyl 2,6-naphthalenedicarboxylate; (10-1.28-0.696) /2=4.01
(4) Dimethyl terephthalate; (27.4-4.01 × 4-1.28) /4=2.53
(5) Ethylene glycol; 15.3 / 4 = 3.83
(6) Polyethylene glycol # 2000; 33.2 / 180.2 = 0.18
(7) Diethylene glycol; (10.4−0.18 × 4) /4=2.42
(1) + (2) + (3) + (4) = 8.52, (5) + (6) + (7) = 6.43 The molar ratio was calculated as follows.
(1) Sodium m-sulfobenzoate; (1.28 / 8.52) × 100 = 15
(2) Trimellitic anhydride; (0.696 / 8.52) × 100 = 8
(3) Dimethyl naphthalenedicarboxylate; (4.01 / 8.52) × 100 = 47
(4) Dimethyl terephthalate; (2.53 / 8.52) × 100 = 30
(5) Ethylene glycol; (3.83 / 6.34) × 100 = 60
(6) Polyethylene glycol # 2000; (0.18 / 6.34) × 100 = 3
(7) Diethylene glycol; (2.42 / 6.34) × 100 = 37
Carboxylic acid component / alcohol component [(1) + (2) + (3) + (4)] / [(5) + (6) + (7)] = 8.52 / 6.43 = 1.33

Example 2
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 1 shows the properties of this polyester resin according to the above methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Similar to Example 1, the copolymerization amount of sodium m-sulfobenzoate, which is an ionic monomer, was large, and the water resistance evaluation 1 could not be evaluated because the polyester resin was dissolved in water. It was found that the decrease in viscosity was small and the water resistance was excellent.

Example 3
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 1 shows the properties of this polyester resin according to the above methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Similar to Example 1, the copolymerization amount of sodium m-sulfobenzoate, which is an ionic monomer, was large, and the water resistance evaluation 1 could not be evaluated because the polyester resin was dissolved in water. It was found that the decrease in viscosity was small and the water resistance was excellent.

Example 4
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 1 shows the properties of this polyester resin according to the above methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Similar to Example 1, the copolymerization amount of sodium m-sulfobenzoate, which is an ionic monomer, was large, and the water resistance evaluation 1 could not be evaluated because the polyester resin was dissolved in water. It was found that the decrease in viscosity was small and the water resistance was excellent.

Example 5
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 1 shows the properties of this polyester resin according to the above methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Similar to Example 1, the copolymerization amount of sodium m-sulfobenzoate, which is an ionic monomer, was large, and the water resistance evaluation 1 could not be evaluated because the polyester resin was dissolved in water. It was found that the decrease in viscosity was small and the water resistance was excellent.

Example 6
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 1 shows the properties of this polyester resin according to the above methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Similar to Example 1, the amount of copolymerization of sodium isethionate, which is an ionic monomer, was large, and in water resistance evaluation 1, it was not possible to evaluate because the polyester resin was dissolved in water. Was found to be small and excellent in water resistance.

Example 7
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 1 shows the properties of this polyester resin according to the above methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Unlike Example 1, since no dissolution was observed in the water resistance evaluation 1, the polyester resin was collected by filtration, the reduced viscosity was measured according to the above method, and the ΔHS reduced viscosity was calculated. It was found that there was no reduction in reduced viscosity and water resistance was excellent. Even in the water resistance evaluation 2, it was found that the reduction in the reduced viscosity was small and the water resistance was excellent.

Example 8
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 1 shows the properties of this polyester resin according to the above methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Similar to Example 1, the copolymerization amount of sodium m-sulfobenzoate, which is an ionic monomer, was large, and the water resistance evaluation 1 could not be evaluated because the polyester resin was dissolved in water. It was found that the decrease in viscosity was small and the water resistance was excellent.

Example 9
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 1 shows the properties of this polyester resin according to the above methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Similar to Example 1, the copolymerization amount of sodium m-sulfobenzoate, which is an ionic monomer, was large, and the water resistance evaluation 1 could not be evaluated because the polyester resin was dissolved in water. It was found that the decrease in viscosity was small and the water resistance was excellent.

Example 10
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 1 shows the properties of this polyester resin according to the above methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Similar to Example 1, the copolymerization amount of sodium m-sulfobenzoate, which is an ionic monomer, was large, and the water resistance evaluation 1 could not be evaluated because the polyester resin was dissolved in water. It was found that the decrease in viscosity was small and the water resistance was excellent.

Comparative Example 1
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 2 shows the properties of this polyester resin according to the above-mentioned methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. In Table 2, each component is described by the raw material name used. The copolymerization amount of the ionic monomer was small, and it could not be dispersed in water.

Comparative Example 2
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 2 shows the properties of this polyester resin according to the above-mentioned methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. The amount of sodium m-sulfobenzoate added was large, it worked as a terminal blocking agent, and the reduced viscosity could not be improved. Further, the strand at the outlet was in a state where there was a large amount of unreacted sodium m-sulfobenzoate. Since the reduced viscosity was low and molecules having no hydrophilic group in the molecular chain aggregated and settled over time, they could not be dispersed in water.

Comparative Example 3
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 2 shows the properties of this polyester resin according to the above-mentioned methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Since the content ratio of trimellitic anhydride and sodium m-sulfobenzoate was not optimized, the reduced viscosity could not be improved as in Comparative Example 2. Since the reduced viscosity was low and molecules having no hydrophilic group in the molecular chain aggregated and settled over time, they could not be dispersed in water.

Comparative Example 4
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 2 shows the properties of this polyester resin according to the above-mentioned methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Since the content ratio of trimellitic anhydride and sodium m-sulfobenzoate was not optimized, gelation occurred during the polymerization. The reduced viscosity could not be measured because it did not dissolve in the solution.

Comparative Example 5
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 2 shows the properties of this polyester resin according to the above-mentioned methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Since dimethyl 5-sodium sulfoisophthalate was used as the ionic monomer, it could be dispersed in water. However, as a result of the water resistance evaluations 1 and 2, it was found that the water resistance was inferior to that of Example 7. The reason why the water resistance is inferior in Example 7 and Comparative Example 5 because the acid component is the same is that sodium sulfonate is contained in the molecular chain by using dimethyl 5-sodium sulfoisophthalate. It was judged.

Comparative Example 6
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 2 shows the properties of this polyester resin according to the above-mentioned methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. The copolymerization amount of dimethyl 5-sodium sulfoisophthalate was large, and the melt viscosity became high due to ion aggregation of sodium sulfonate in the molecular chain, and the polymerization had to be terminated in a state where the reduced viscosity was low. Since the reduced viscosity was low and molecules having no hydrophilic group in the molecular chain aggregated and settled over time, they could not be dispersed in water. Further, the copolymerization amount of dimethyl 5-sodium sulfoisophthalate, which is an ionic monomer, is large, and in water resistance evaluation 1, the polyester resin was dissolved in water. However, in water resistance evaluation 2, the reduction in reduced viscosity is large and the water resistance is high. I found it inferior. The reason why the water resistance was poor was judged to be because sodium sulfonate was contained in the molecular chain by using dimethyl 5-sodium sulfoisophthalate.

Comparative Example 7
The polyester resin was polymerized according to Example 1, except that the raw material type and blending ratio were changed. Table 2 shows the properties of this polyester resin according to the above-mentioned methods, the results of reduced viscosity, glass transition temperature, water dispersibility determination, water resistance evaluation, and composition analysis. Since dimethyl 5-sodium sulfoisophthalate was used as the ionic monomer, it could be dispersed in water. However, as a result of the water resistance evaluations 1 and 2, it was found that the water resistance was inferior to that of Example 7. In Example 7 and Comparative Example 7, the acid component and the glycol composition ratio are the same, so the reason why the water resistance is poor is that sodium sulfonate is contained in the molecular chain by using dimethyl 5-sodium sulfoisophthalate. Judging because it is.

The polyester resin of the present invention can increase the amount of ionicity and can be easily dispersed in water. Further, since the polyester resin of the present invention is excellent in water resistance, it is useful to be applied to a member that is exposed for a long time under high temperature and high humidity such as outdoors.

Claims (5)

A polyester resin composed of a carboxylic acid component and an alcohol component, and when the total carboxylic acid component is 100 mol% and the total alcohol component is 100 mol%, (A) a dicarboxylic acid component having no sulfonate group is 50 to 100 Mol%, (B) 50 to 100 mol% of the glycol component having no sulfonate group, (C) carboxylic acid component (C1) represented by the following (formula 1) and (formula 2) 3 to 30 mol% of a compound component containing at least one sulfonate group selected from the group consisting of alcohol components (C2) (wherein (C1) is (C2) relative to 100 mol% of all carboxylic acid components ) With respect to 100 mol% of all alcohol components), and (D) a carboxylic acid component (D1) having three or more functional groups and an alcohol component having three or more functional groups (D ) At least one compound component selected from the group consisting of 1 to 20 mol% (where (D1) is based on 100 mol% of all carboxylic acid components, and (D2) is based on 100 mol% of all alcohol components. And a polyester resin characterized by satisfying the following formula (I).
[In formula (1), X ¹ represents a divalent aromatic group having 6 to 20 carbon atoms or an alkylene group having 1 to 8 carbon atoms, and M ⁺ represents a metal ion, a tetraalkylphosphonium ion or a tetraalkylammonium ion. Represents. ]
[In the formula (2), X ² represents a divalent aromatic group having 6 to 20 carbon atoms or an alkylene group having 1 to 8 carbon atoms, and M ⁺ represents a metal ion, a tetraalkylphosphonium ion or a tetraalkylammonium ion. Represents. ]
(C1 + C2) / (D1 + D2) = 1.5 to 7.0 Formula (I)
[C1 and C2 represent the content (mol%) of the component (C1) and the content (mol%) of the component (C2), respectively, and D1 and D2 represent the content (mol%) of the component (D1), respectively. , (D2) represents the content (mol%) of the component. ] (C1) is a carboxylic acid component represented by the following (formula 3), (C2) is an alcohol component represented by the following (formula 4), (D1) is trimellitic acid, and (D2) is trimethyl. The polyester resin according to claim 1, which is methylolpropane.
The polyester resin according to claim 1 or 2, wherein the component (A) is an aromatic dicarboxylic acid. The polyester resin according to claim 3, wherein the aromatic dicarboxylic acid is one or more selected from 2,6-naphthalenedicarboxylic acid and terephthalic acid. The water dispersion formed using the polyester resin in any one of Claims 1-4.