Polyester resin aqueous dispersion

Abstract

The purpose of the present invention is to provide a polyester resin aqueous dispersion in which dispersibility of a polyester resin is excellent, and the polyester resin aqueous dispersion exhibits high adhesive strength.　The polyester resin aqueous dispersion is characterized by comprising a polyester resin (A), wherein: the reduced viscosity of the polyester resin (A) is 0.50 dl / g or more; the acid value (AV) of the polyester resin (A) is 100 eq / t or more; and the acid value (AV2) of carboxy groups belonging to a tricarboxylic acid component in which two carboxy groups form an ester bond, and one carboxy group is present in a free carboxy group state is 70 eq / t or more.

Description

Polyester resin aqueous dispersion

[0001] This invention relates to an aqueous dispersion of polyester resin.

[0002] High molecular weight polyester resins, composed of polycarboxylic acid and polyhydric alcohol components, are widely used as binder components in paints, inks, adhesives, and coatings due to their excellent film-forming properties, resistance to organic solvents (solvent resistance), weather resistance, and adhesion to various substrates. In recent years, in particular, there has been a trend to restrict the use of organic solvents from the standpoint of environmental protection, resource conservation, regulations on hazardous materials under the Fire Service Act, and improvement of the workplace environment. As a result, there has been active development of polyester resin aqueous dispersions, in which polyester resin is finely dispersed in an aqueous medium, as polyester resin-based binders that can be used in the above applications.

[0003] To achieve a stable aqueous dispersion of polyester resin, the polyester resin must first have a high acid value. As disclosed in Patent Documents 1 to 3, in order to increase the acid value of the polyester resin, a prepolymer is generally obtained by esterifying a polycarboxylic acid component with a polyhydric alcohol component, and then modification with an acid anhydride is performed.

[0004] Japanese Patent Publication No. 2014-208741, Japanese Patent Publication No. 2013-75966, International Publication No. 2024 / 157683

[0005] Increasing the molecular weight of the polyester resin blended into the aqueous dispersion and thereby increasing its reduced viscosity is effective in improving adhesive strength. However, in the method described in Patent Document 1, when attempting to increase the molecular weight of the polyester resin and thus its reduced viscosity, the number of hydroxyl groups in the polyester resin decreases relatively, reducing the number of reaction sites with acid anhydrides and limiting the number of carboxyl groups that can be introduced. It is also possible to copolymerize polyfunctional monomers to increase the number of reaction sites, but increasing the amount of copolymerization causes the polyester resin to gel before the molecular weight can be increased. Even if the molecular weight can be increased, it decreases significantly during the reaction with acid anhydrides. Patent Document 2 obtains a high molecular weight and high acid value polyester resin by using dianhydrides in the addition reaction. However, because dianhydrides have many reaction sites, attempting to increase the molecular weight leads to problems such as the generation of microgels and large variations in molecular weight. Furthermore, when this resin is dispersed in aqueous dispersion, problems arise such as poor dispersion due to the microgels and poor storage stability due to the reaction of dianhydrides at the polymer ends over time. Although Patent Document 3 yields a polyester resin with high molecular weight and high acid value, it contains many unreacted or monoesterized acid anhydrides, which can inhibit micelle formation during water dispersion and lead to poor storage stability.

[0006] This invention was made against the backdrop of the aforementioned prior art problems. In other words, the object of this invention is to provide a polyester resin aqueous dispersion that exhibits excellent dispersibility and high adhesive strength.

[0007] As a result of diligent research, the inventors of the present invention have found that the above-mentioned problems can be solved by the means described below, and have arrived at the present invention. That is, the present invention consists of the following configuration.

[0008] [1] The reduced viscosity of polyester resin (A) is 0.50 dl / g or more, the acid value (AV) of polyester resin (A) is 100 eq / t or more, and the acid value (AV) of the carboxyl group belonging to the tricarboxylic acid component in which two carboxyl groups form an ester bond and one carboxyl group exists as a free carboxyl group ２[1] A polyester resin aqueous dispersion characterized by containing a polyester resin (A) having a ratio of 70 eq / t or more. [2] The polyester resin aqueous dispersion according to [1], wherein the amount of unreacted tricarboxylic acid monomer is 1000 ppm or less. [3] The polyester resin aqueous dispersion according to [1] or [2], wherein the content of the tricarboxylic acid component in which three carboxyl groups in the polyester resin (A) form an ester bond is 2.0 mol% or less with respect to the total amount of polycarboxylic acid constituting the polyester resin (A). [4] The polyester resin aqueous dispersion according to any one of [1] to [3], wherein the content of antimony and zinc is 200 ppm or less. [5] The polyester resin aqueous dispersion according to any one of [1] to [4], wherein the dicarboxylic acid component constituting the polyester resin (A) is one or more selected from the group consisting of aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, and aromatic dicarboxylic acid. [6] The polyester resin aqueous dispersion according to any one of [1] to [5], wherein the weight-average molecular weight (Mw) of the polyester resin (A) is 20,000 to 300,000. [7] The polyester resin aqueous dispersion according to any one of [1] to [6], wherein the polycarboxylic acid component with tetravalent or higher is 6 mol% or less in 100 mol% of the polycarboxylic acid constituting the polyester resin (A). [8] The polyester resin aqueous dispersion according to any one of [1] to [7], wherein the solid content concentration of the polyester resin (A) in the polyester resin aqueous dispersion is 10 to 45% by mass. [9] The polyester resin aqueous dispersion according to any one of [1] to [8], wherein the content of the polyester resin (A) in 100% by mass of the resin contained in the polyester resin aqueous dispersion is 20% by mass or more.

[10] The polyester resin aqueous dispersion according to any one of [1] to [9], wherein the content of the organic solvent in 100% by mass of the polyester resin aqueous dispersion is 30% by mass or less.

[11] An adhesive composition comprising an aqueous dispersion of polyester resin according to any one of [1] to

[10] .

[0009] According to the present invention, a polyester resin aqueous dispersion is obtained that exhibits excellent dispersibility and storage stability of polyester resin, as well as high adhesive strength.

[0010] <Polyester Resin Aqueous Dispersion> The polyester resin aqueous dispersion of the present invention has a reduced viscosity of polyester resin (A) of 0.50 dl / g or more, an acid value (AV) of polyester resin (A) of 100 eq / t or more, and the acid value (AV) of the carboxyl group belonging to the tricarboxylic acid component in which two carboxyl groups form an ester bond and one carboxyl group exists in the state of a free carboxyl group. ２ The present invention is characterized by containing a polyester resin (A) having a density of 70 eq / t or more.

[0011] <Polyester Resin (A)> Polyester resin (A) has a chemical structure obtained by polycondensation of a polycarboxylic acid component and a polyhydric alcohol component, preferably having a chemical structure obtained by polycondensation of a dicarboxylic acid component and a tricarboxylic acid component and a diol component. In this disclosure, the polycarboxylic acid component includes a dicarboxylic acid component, a tricarboxylic acid component which is a trivalent polycarboxylic acid, and a polycarboxylic acid component which is tetravalent or higher, and the polyhydric alcohol component includes a diol component and a polyhydric alcohol component which is trivalent or higher. Furthermore, the various polycarboxylic acids exemplified below include not only the polycarboxylic acid itself, but also esters of the polycarboxylic acid and polycarboxylic acid anhydrides.

[0012] The dicarboxylic acid component and the diol component each consist of one or more selected components. The dicarboxylic acid component constituting the polyester resin (A) is not particularly limited, but the dicarboxylic acids or their esters and dicarboxylic acid anhydrides shown below can be used. Specifically, examples of dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. Examples of aliphatic dicarboxylic acids include adipic acid, sebacic acid, dimer acid, fumaric acid, maleic acid, succinic acid, etc. Examples of alicyclic dicarboxylic acids include 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, etc. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 2,5-frandicarboxylic acid, 5-sodium sulfodimethylisophthalic acid and their esters and acid anhydrides can be used. Among these, aliphatic dicarboxylic acids and aromatic dicarboxylic acids are preferred as the dicarboxylic acid component, and it is more preferable that at least aromatic dicarboxylic acids are included. Preferred aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and 2,5-franzicarboxylic acid; more preferably terephthalic acid, isophthalic acid, orthophthalic acid, and 2,5-franzicarboxylic acid; and even more preferably terephthalic acid and isophthalic acid. When aromatic dicarboxylic acids are included, the aromatic dicarboxylic acid component is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, and particularly preferably 70 mol% or more, in 100 mol% of the dicarboxylic acid component constituting the polyester resin (A). It is also preferable to use terephthalic acid and isophthalic acid in combination as aromatic dicarboxylic acids, and their content ratio (terephthalic acid:isophthalic acid) is preferably 5:95 to 95:5, more preferably 20:80 to 80:20, even more preferably 30:70 to 70:30, and particularly preferably 40:60 to 60:40, on a molar basis. By keeping the amounts of terephthalic acid and isophthalic acid within the aforementioned range, it is possible to create an aqueous dispersion that better balances water dispersibility and storage stability.

[0013] From the standpoint of compliance with food hygiene laws in various countries, it is preferable that the polyester resin (A) contains a small amount of aromatic dicarboxylic acid having a sulfonic acid group (e.g., sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5(4-sulfophenoxy)isophthalic acid, etc.). The content of aromatic dicarboxylic acid having a sulfonic acid group in 100 mol% of polycarboxylic acid components is preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, even more preferably 1 mol% or less, and particularly preferably 0 mol%.

[0014] The diol component constituting the polyester resin (A) is not particularly limited, but examples include aliphatic diols, alicyclic diols, aromatic diols, and bisphenol skeleton-containing monomers. Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,3-hexanediol, and 2-methyl-1,3-hexanediol. Tyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-propyl-1,3-propanediol, 2,2-di-n-propyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, dimergio Examples of diols that can be used include aliphatic diols, diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol, polypropylene glycol, etc., as alicyclic diols, 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, etc., as aromatic diols, diphenolic acids, etc., as bisphenol skeleton-containing monomers, bisphenol A, bisphenol B, bisphenol E, bisphenol F, bisphenol AP, bisphenol BP, bisphenol P, bisphenol PH, bisphenol S, bisphenol Z, 4,4'-dihydroxybenzophenone, bisphenol fluorene and their hydrogenated products, and glycols such as ethylene oxide adducts and propylene oxide adducts obtained by adding 1 to several moles of ethylene oxide or propylene oxide to the hydroxyl group of bisphenols. Aliphatic diols and alicyclic diols are preferred as diols.When aliphatic diols and alicyclic diols are included, the diol component constituting the polyester resin (A) is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more, and may be 100 mol%. Examples of aliphatic diols include C. ２－６ Aliphatic diols are more preferred, and among alicyclic diols, 1,4-cyclohexanedimethanol is more preferred. Furthermore, it is preferable to use ethylene glycol and neopentyl glycol in combination as aliphatic diols, and the content ratio of these (ethylene glycol:neopentyl glycol) on a molar basis is preferably 5:95 to 95:5, more preferably 20:80 to 80:20, even more preferably 30:70 to 70:30, and particularly preferably 40:60 to 60:40. By using the above content ratio, it is possible to create an aqueous dispersion that better balances water dispersibility and storage stability.

[0015] Polyester resin (A) can also be copolymerized with lactones or lactams. For example, ε-caprolactone and ε-caprolactam can be used.

[0016] The polycarboxylic acid and polyhydric alcohol components that make up the polyester resin (A) can be made from raw materials derived from biomass resources. Biomass resources include materials that are stored when sunlight energy is converted into starch, cellulose, etc. through the photosynthesis of plants, the bodies of animals that grow by eating plants, and products made by processing plant or animal bodies. Among these, plant resources are more preferred as biomass resources, and examples include wood, rice straw, rice husks, rice bran, old rice, corn, sugarcane, cassava, sago palm, okara, corn cob, tapioca residue, bagasse, vegetable oil residue, potatoes, buckwheat, soybeans, oils and fats, waste paper, papermaking residue, fishery residue, livestock excrement, sewage sludge, food waste, etc. More preferably are corn, sugarcane, cassava, and sago palm. Specific examples of polycarboxylic acid raw materials derived from biomass resources include, for example, adipic acid, sebacic acid, fumaric acid, itaconic acid, terephthalic acid, and 2,5-franzicarboxylic acid. Specific examples of polyhydric alcohol raw materials derived from biomass resources include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol.

[0017] Polyester resin (A) is copolymerized with a tricarboxylic acid component. Examples of tricarboxylic acid components include trivalent aromatic carboxylic acids such as trimellitic acid, trimesic acid, and trimellitic anhydride (TMA); trivalent aliphatic carboxylic acids such as citric acid and citric anhydride; and trivalent alicyclic tricarboxylic acids such as 1,2,4-cyclohexanetricarboxylic acid, 1,3,5-cyclohexanetricarboxylic acid, and cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride. Among these, trivalent aromatic carboxylic acids are preferred, and trimellitic acid or trimellitic anhydride is more preferred. By copolymerizing the tricarboxylic acid component, it becomes easier to introduce the following into the main chain of polyester resin (A): (1) a tricarboxylic acid component in which three carboxyl groups form ester bonds (with the polyester main chain) (hereinafter sometimes referred to as "triester"), (2) a tricarboxylic acid component in which two carboxyl groups form ester bonds (with the polyester main chain) and one carboxyl group exists as a free carboxyl group (hereinafter sometimes referred to as "diester"), and (3) a tricarboxylic acid component in which one carboxyl group forms ester bonds (with the polyester main chain) and two carboxyl groups exist as free carboxyl groups (hereinafter sometimes referred to as "monoester"). The triester can give the polyester a branched structure, thus contributing to the high molecular weight of polyester resin (A). In the diester and monoester, when dispersed in water, the one or two carboxyl groups remaining in a free state are used to form salts with a base, thus contributing to stable water dispersibility and storage stability.

[0018] Polyester resin (A) contains, for example, 1.0 mol% or more of tricarboxylic acid components, preferably 1.0 to 10.0 mol%, more preferably 2.0 to 10.0 mol%, more preferably 2.5 to 9.0 mol%, and even more preferably 3.0 to 8.0 mol% of the total polycarboxylic acid components. If the amount falls below the lower limit, it becomes difficult to increase the acid value of polyester resin (A). Conversely, if it exceeds the upper limit, the tricarboxylic acid components tend to remain unreacted, which is undesirable.

[0019] The content of the triester compound in polyester resin (A) is, for example, 0.1 to 2.0 mol%, preferably 0.5 to 2.0 mol%, more preferably 0.6 to 1.8 mol%, and even more preferably 0.7 to 1.6 mol%, relative to the total amount of polycarboxylic acid constituting polyester resin (A). Keeping it below the upper limit makes it easier to suppress gelation during the production of polyester resin (A). The content of the triester compound is １ It can be measured by H-NMR and TOCSY spectroscopy, for example, １ When using H-NMR and TOCSY spectral measurements, first １ The integral value of the peak derived from the tricarboxylic acid component is calculated by 1H-NMR measurement. Next, by TOCSY spectral measurement, the integral values ​​of the peaks that form triesters and the other peaks of the tricarboxylic acid component are calculated separately, thereby revealing the content of the triester-forming component among the tricarboxylic acid components.

[0020] The acid value (AV) of the carboxyl group belonging to the diester compound in polyester resin (A) ２ The q / t is 70 eq / t or more, preferably 70 to 500 eq / t, more preferably 90 to 450 eq / t, more preferably 110 to 400 eq / t, even more preferably 130 to 350 eq / t, and even more preferably 150 to 300 eq / t. Keeping it below the upper limit makes it easier to suppress gelation during the production of polyester resin (A). Keeping it above the lower limit contributes to stable water dispersion and storage stability.

[0021] The acid value (AV) of the carboxyl group belonging to the monoester compound in polyester resin (A) １ The ) is preferably 400 eq / t or less, more preferably 300 eq / t or less, even more preferably 200 eq / t or less, and even more preferably 120 eq / t or less, and the lower limit is not particularly limited but is usually 1 eq / t or more, and may be 20 eq / t or more, 40 eq / t or more, or 60 eq / t or more (i.e., preferably 1 to 400 eq / t, 20 to 300 eq / t, 40 to 200 eq / t, or 60 to 120 eq / t).

[0022] The acid value (AV ２ ) of the diester form and the acid value (AV １ ) of the monoester form may be measured directly, or may be determined by calculation when direct measurement is difficult. For example, when the polycarboxylic acid component consists of a dicarboxylic acid and a tricarboxylic acid, it can be determined based on the following formulas (A) to (D). First, let the tricarboxylic acid component contained in the polyester resin (A) be Xn. First, the following formula (A) holds for the acid value of the polyester resin (A). The acid value (AV) of the polyester resin (A) = the acid value (AV ２ ) of the diester form + the acid value (AV １ ) of the monoester form + the acid value (AV ｄ ) derived from the dicarboxylic acid component + the acid value (AV ｕ ) derived from unreacted Xn... (A) Next, focusing on the ester structure of the Xn component, the following formula (B) holds. The content (W) of the Xn component = the content (W ３ ) of the triester form of Xn + the content (W ２ ) of the diester form of Xn + the content (W １ ) of the monoester form of Xn + the amount of unreacted Xn (W ｕ )... (B) Also, since there is one free carboxy group in one diester form of Xn and two free carboxyl groups in one monoester form of Xn, taking into account the molecular weight Mx of Xn, the following relationships of formulas (C) to (D) hold between the acid value and the content. The acid value (AV ２ ) of the diester form = 10 ６ ×{(W ２ + W １ ) / 100} / Mx × {W ２ / (W ２ + W １ )}... (C) The acid value (AV １ ) of the monoester form = 10 ６ ×{(W ２ + W １ ) / 100} / Mx × {W １ / (W ２ + W １ )} × 2... (D) In formula (A), AV can be determined, for example, by the method described in the examples. AVｄ teeth １ The result obtained by 1H-NMR measurement, etc., is converted into an acid value per ton of sample. AV ｕ Similarly, the result obtained by HPLC analysis, etc., is converted to an acid value per ton of sample. In formula (B), W is １ H-NMR measurement, W ３ teeth １ This can be determined by H-NMR measurement and TOCSY spectral measurement, etc. ｕ This can be determined by HPLC analysis, etc. Then AV, AV ２ AV １ AV ｄ AV ｕ , W, W ３ , W ２ , W １ and W ｕ Of the 10 variables, 6 can be directly determined. For the 4 unknown variables, the four equations (A) to (D) hold true, and therefore AV can be determined using equations (A) to (D). ２ and AV １ This is calculated. AV ２ and AV １ When calculating these values, they may sometimes be calculated as negative. This is presumably due to the error contained in the measured values ​​used in the calculation, and negative values ​​are acceptable. In Xn, n represents the number of types of tricarboxylic acid; for example, if there is one type of tricarboxylic acid, then X １ If there are two or more types, then X １ , X ２ ...as AV for each component ２ and AV １ You should calculate the result and then sum it up.

[0023] In polyester resin (A), the molecular chain ends of the polyester may be carboxyl groups derived from the dicarboxylic acid component that constitutes the polyester main chain. Polyester resin (A) is also characterized by a large amount of carboxyl groups derived from the dicarboxylic acid component, and the acid value (AV) of the carboxyl groups belonging to the dicarboxylic acid component that constitutes the polyester main chain is also important. ｄThe acid value (AV) is, for example, 25 to 400 eq / t, preferably 35 to 400 eq / t, more preferably 40 to 300 eq / t, even more preferably 45 to 200 eq / t, and even more preferably 50 to 100 eq / t. By keeping it within this range, the amount of tricarboxylic acid used can be reduced, which leads to the suppression of gelation during manufacturing. Furthermore, keeping it within this range also results in good storage stability for the polyester resin (A). Acid value (AV) ｄ To adjust the value within the aforementioned range, it is desirable to perform, for example, the polycondensation reaction after the addition of tricarboxylic acid, as described later.

[0024] The acid value (AV) of the polyester resin (A) is 100 eq / t or higher, preferably 100 to 1000 eq / t, more preferably 180 to 1000 eq / t, more preferably 200 to 800 eq / t, and even more preferably 230 to 500 eq / t. By keeping it within this range, the dispersibility of the polyester resin (A) in the aqueous dispersion is good.

[0025] In polyester resin (A), some of the tricarboxylic acid component may remain unreacted, but it is preferable that the amount of unreacted tricarboxylic acid component be small. Specifically, the amount of unreacted tricarboxylic acid monomer in the aqueous dispersion is preferably 1000 ppm or less, more preferably 900 ppm or less, and even more preferably 800 ppm or less. In practical terms, it may also be 50 ppm or more, 100 ppm or more, or 200 ppm or more (i.e., preferably 50 to 1000 ppm, 100 to 900 ppm, or 200 to 800 ppm). By keeping the amount of unreacted tricarboxylic acid component within the above range, micelle formation during aqueous dispersion is not inhibited, and a stable aqueous dispersion can be created. Furthermore, keeping it within the above range also improves the storage stability of the aqueous dispersion. In addition, in polyester resin (A), the acid value (AV) derived from the unreacted tricarboxylic acid component is ｕ The ratio is preferably 1 to 200 eq / t, more preferably 3 to 100 eq / t, and even more preferably 5 to 50 eq / t.

[0026] Furthermore, the polyester resin (A) may be copolymerized with a polycarboxylic acid component with a tetravalent or higher valency and / or a polyol component with a trivalent or higher valency. Examples of polycarboxylic acid components with a tetravalent or higher valency include aromatic carboxylic acids such as pyromellitic acid, benzophenonetetracarboxylic acid, pyromellitic anhydride (PMDA), and ethylene glycol bistrimellitate dianhydride, and aliphatic carboxylic acids such as 1,2,3,4-butanetetracarboxylic acid, which can be used alone or in combination of two or more. The polycarboxylic acid component with a tetravalent or higher valency is preferably 0 to 6 mol%, more preferably 0 to 4 mol%, even more preferably 0 to 1.5 mol%, and particularly preferably 0 to 0.5 mol% of 100 mol% of the polycarboxylic acid component of the polyester resin (A). By keeping it below the above upper limit, the generation of microgels and gelation of the resin can be prevented. In addition, thickening during the production of the polyester resin (A) can be prevented, and molecular weight control can be easily made, enabling stable mass production. Examples of polyhydric alcohol components with a valency of 3 or higher include glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, α-methylglucose, mannitol, and sorbitol, which can be used individually or in combination of two or more.

[0027] The hydroxyl value (OHV) of the polyester resin (A) is preferably 5 to 70 eq / t, more preferably 10 to 60 eq / t, and even more preferably 15 to 50 eq / t.

[0028] The reduced viscosity (ηsp / c) of the polyester resin (A) is 0.50 dl / g or higher, preferably 0.50 to 1.4 dl / g, more preferably 0.52 to 1.4 dl / g, more preferably 0.55 to 1.2 dl / g, and even more preferably 0.60 to 1.0 dl / g. Setting it above the lower limit ensures good adhesion when used as an adhesive layer for laminated films. Setting it below the upper limit prevents damage to the substrate film during peeling.

[0029] The number-average molecular weight (Mn) of the polyester resin (A) is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and even more preferably 9,000 to 30,000.

[0030] The weight-average molecular weight (Mw) of the polyester resin (A) is preferably 20,000 to 300,000, more preferably 30,000 to 200,000, even more preferably 40,000 to 150,000, and even more preferably 50,000 to 100,000.

[0031] The dispersion degree (Mw / Mn) of the polyester resin (A) is preferably 2.0 to 14.0, more preferably 3.0 to 9.0, and even more preferably 4.0 to 7.0.

[0032] The glass transition temperature (Tg) of the polyester resin (A) is preferably -100 to 150°C, more preferably -80 to 120°C, even more preferably -50 to 100°C, and particularly preferably 0 to 90°C.

[0033] The polyester resin (A) can be produced by any known method that can produce a polycondensate of a polycarboxylic acid component and a polyhydric alcohol component, but it is desirable that the method includes, for example, 1) a step of esterifying the polycarboxylic acid component and the polyhydric alcohol component, 3) a step of reacting the reactant obtained in the above step with a tricarboxylic acid, and 4) a step of polycondensing the reactant obtained in the above step. By polycondensing after adding the tricarboxylic acid, it becomes easier to form a diester of the tricarboxylic acid. This makes it possible to increase the acid value while increasing the molecular weight of the polyester resin (A) produced while suppressing the occurrence of gelation. After step 1), if necessary, step 2) a step of polycondensing the reactant obtained in step 1) may be carried out. Each step will be described in detail below.

[0034] In step 1), an oligomer is produced by esterifying a polycarboxylic acid component with a polyhydric alcohol component. The polycarboxylic acid component and polyhydric alcohol component may be those mentioned above as appropriate.

[0035] In step 1), a polymerization catalyst can be used. Conventional known polymerization catalysts such as titanium compounds, antimony compounds, germanium compounds, and metal acetates can be used as polymerization catalysts. For example, titanium compounds such as tetra-n-butyl titanate, tetraisopropyl titanate, and titanium oxyacetyl cetonate can be used; antimony compounds such as antimony trioxide and tributoxyantimony can be used; germanium compounds such as germanium oxide and tetra-n-butoxygermanium can be used; and metal acetates such as magnesium, iron, zinc, manganese, cobalt, and aluminum can be used. These can be used individually or in combination of two or more. However, increasing the amount of antimony compounds or zinc used as polymerization catalysts may affect the reaction behavior, making it difficult to obtain a polyester resin (A) with the desired properties. Therefore, it is desirable to use as little of these as possible. The antimony and zinc content in the aqueous dispersion is preferably 0 to 200 ppm, more preferably 0 to 100 ppm, even more preferably 0 to 50 ppm, even more preferably 0 to 1 ppm, and particularly preferably 0 ppm. The amount of metal derived from the polymerization catalyst in the aqueous dispersion can be determined by the method described in the examples.

[0036] As the polymerization catalyst, at least a titanium compound is preferably used. When the total amount of metal derived from the polymerization catalyst in the aqueous dispersion is 100% by mass, the titanium content is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and particularly preferably 80% by mass or more, and may also be 90% by mass or more. Furthermore, the titanium content in the aqueous dispersion is preferably 5 ppm or more, more preferably 10 ppm or more, even more preferably 20 ppm or more, and particularly preferably 30 ppm or more.

[0037] The esterification reaction in step 1) is preferably carried out under heating. The reaction temperature is preferably 180 to 280°C, more preferably 200 to 260°C. The reaction time is preferably 1 to 10 hours, more preferably 2 to 8 hours.

[0038] In step 2), the reactant (oligomer) obtained in step 1) is polycondensed to produce a prepolymer. This step makes it easier to increase the molecular weight of the final polyester resin (A). The polycondensation reaction in step 2) is preferably carried out under heating, with a reaction temperature of preferably 180 to 280°C, more preferably 200 to 260°C. The reaction time is preferably 0.1 to 5 hours, more preferably 0.5 to 3 hours.

[0039] Step 2) is best carried out under vacuum or in an inert atmosphere (for example, in a nitrogen stream).

[0040] The hydroxyl value (OHV) of the prepolymer obtained after step 2) is preferably 200 to 500 eq / t, more preferably 220 to 400 eq / t, and even more preferably 250 to 350 eq / t. Keeping it within this range ensures a good balance with the carboxyl groups of the tricarboxylic acid used in the subsequent step 3). For example, if the hydroxyl groups of the prepolymer are in excess of the carboxyl groups of the tricarboxylic acid, the three carboxyl groups of the tricarboxylic acid will react, easily forming a triester, which may lead to gelation in subsequent steps. On the other hand, if the carboxyl groups of the tricarboxylic acid are in excess of the hydroxyl groups of the prepolymer, some of the tricarboxylic acid components are likely to remain unreacted.

[0041] The acid value (AV) of the prepolymer is preferably 0.5 to 50 eq / t, more preferably 1.0 to 30 eq / t, and even more preferably 2.0 to 20 eq / t. Within this range, the number of carboxyl groups does not increase excessively, making it easier to adjust the balance between the carboxyl groups and the hydroxyl groups of the prepolymer.

[0042] The reduced viscosity (ηsp / c) of the prepolymer is preferably 0.27 to 0.80 dl / g, more preferably 0.29 to 0.75 dl / g, and even more preferably 0.31 to 0.70 dl / g. Within this range, it is easier to adjust the hydroxyl value of the prepolymer to the desired range, and it is easier to increase the molecular weight of the final polyester.

[0043] The number-average molecular weight (Mn) of the prepolymer is preferably 1,000 to 20,000, more preferably 3,000 to 15,000, and even more preferably 5,000 to 10,000. When the Mn of the prepolymer is large, the number of terminal hydroxyl groups in the prepolymer decreases relatively, and the hydroxyl value of the prepolymer tends to decrease. Similarly, when the Mn of the prepolymer is small, the number of terminal hydroxyl groups in the prepolymer increases relatively, and the hydroxyl value of the prepolymer tends to increase. Within the above range, it is easy to adjust the hydroxyl value of the prepolymer to the desired range, and it is also easy to make the final polyester with a high molecular weight.

[0044] In step 3), a tricarboxylic acid adduct is produced by reacting the reactant (oligomer or prepolymer) obtained in the previous step with a tricarboxylic acid. By carrying out this step, triesters, diesters, and monoesters are more easily formed on the main chain of the polyester resin (A), making it easier to produce a polyester resin (A) with a high molecular weight and high acid value. The addition reaction in step 3) is preferably carried out under heating, and the reaction temperature is preferably 180 to 280°C, more preferably 200 to 260°C. The reaction time is preferably 0.1 to 4 hours, more preferably 0.5 to 3 hours.

[0045] The amount of tricarboxylic acid used in step 3) is preferably 1.0 mol or more, more preferably 2.0 to 10 mol, more preferably 3.0 to 9 mol, and even more preferably 3.5 to 8 mol, relative to 100 mol of the polycarboxylic acid component used in step 1). If the amount falls below the lower limit, it becomes difficult to increase the acid value of the polyester. If the amount exceeds the upper limit, the tricarboxylic acid component is more likely to remain unreacted.

[0046] In step 4), the reactant (tricarboxylic acid adduct) obtained in step 3) is polycondensed to produce polyester resin (A). By carrying out this step, triesters, diesters, and monoesters are more readily formed in the main chain of polyester resin (A), which is advantageous for producing polyester resin (A) with high molecular weight and high acid value. The polycondensation reaction in step 4) is preferably carried out under heating, and the reaction temperature is preferably 215 to 280°C, more preferably 225 to 260°C. The reaction time is preferably 0.1 to 5 hours, more preferably 0.5 to 3 hours.

[0047] Step 4) may be carried out under vacuum or in an inert atmosphere (for example, in a nitrogen stream). The polyester resin (A) obtained in step 4) may then be removed and placed in a water bath or the like.

[0048] <Polyester Resin Aqueous Dispersion> The polyester resin aqueous dispersion of the present invention is an aqueous dispersion containing the polyester resin (A) described above. The polyester resin aqueous dispersion of the present invention may also contain resins other than the polyester resin (A) described above, to the extent that it is suitable for the spirit of the present invention. The content of polyester resin (A) is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, out of 100% by mass of the resin contained in the polyester resin aqueous dispersion.

[0049] The polyester resin aqueous dispersion of the present invention can be prepared by methods such as (i) dissolving polyester resin (A) in an organic solvent in which polyester resin (A) dissolves, and then sequentially adding a basic compound and water as needed to disperse the dispersion; or (ii) adding polyester resin (A), water, an organic solvent in which polyester resin (A) dissolves, and a basic compound as needed, and then heating and dispersing the dispersion. Furthermore, if it is desired to reduce the amount of organic solvent or to completely remove it to obtain an aqueous dispersion, it is also possible to dissolve and disperse using an organic solvent having a boiling point of 100°C or lower, and then remove the solvent by heating or under reduced pressure. In the case of polyester resin, the former method (i) is preferable from the viewpoint of film-forming properties.

[0050] In this case, the temperature at which the polyester resin (A) is dissolved is preferably 40 to 160°C, more preferably 50 to 140°C, even more preferably 60 to 130°C, and most preferably 70 to 100°C. At temperatures above 40°C, the polyester resin (A) dissolves sufficiently, preventing entanglement of molecular chains, while at temperatures below 160°C, thermal degradation of the polyester resin (A) can be suppressed.

[0051] Organic solvents that can dissolve polyester resin (A) by heating in a temperature range of 40 to 160°C include methyl ethyl ketone, cyclohexanone, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, 1,3-dioxolane, 1,2-hexanediol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and triethylene glycol monobutyl ether. In addition to the above, n-butanol, isopropyl alcohol, diacetone alcohol, 2-ethylhexanol, acetonitrile, and 1,3-oxolane may also be used in combination. Among these, methyl ethyl ketone, tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, and isopropyl alcohol, which have boiling points of 100°C or less, are particularly preferred. By using these methods, the amount of organic solvent remaining in the system can be reduced in a short time during the subsequent solvent removal process.

[0052] When the polyester resin (A) is dissolved at a temperature of 100°C or higher, it is preferable to cool the temperature of the polyester resin (A) solution to 100°C or lower, and then, while stirring the resin solution, sequentially add water and, if necessary, a basic compound to perform a phase change and obtain an aqueous dispersion.

[0053] In the present invention, it is preferable to prepare the aqueous dispersion of polyester resin with an organic solvent content of 30% by mass or less in 100% by mass. A content of 30% by mass or less prevents the development of a flash point due to the organic solvent.

[0054] The basic compound used when forming the polyester resin (A) of the present invention into an aqueous dispersion is preferably a compound that volatilizes during the drying and baking processes during film formation, such as ammonia and / or organic amine compounds with a boiling point of 250°C or lower. Preferably, examples include triethylamine, N,N-diethylethanolamine, N,N-dimethylethanolamine, aminoethanolamine, N-methyl-N,N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine, etc. These basic compounds are required in an amount that can at least partially neutralize the carboxyl groups of the polyester resin (A), and specifically, it is desirable to add 0.5 to 1.5 equivalents relative to the carboxyl group equivalents.

[0055] The average particle size of the polyester resin aqueous dispersion according to the present invention is extremely important as it greatly affects the appearance and storage stability of the coating film, and is preferably between 30 and 200 nm. When the average particle size is 200 nm or less, the dispersion is stable and the film-forming properties are also good, resulting in a good appearance of the resulting coating film. Furthermore, by setting the average particle size to 30 nm or more, it is possible to prevent the dispersion particles from fusing or agglomerating.

[0056] The solid content concentration of the polyester resin (A) in the aqueous dispersion of polyester resin of the present invention is preferably 10 to 45% by mass, more preferably 15 to 40% by mass, and even more preferably 20 to 35% by mass. If it is below the upper limit, the viscosity of the aqueous dispersion is appropriate, and aggregation between resin particles is prevented, resulting in good dispersion stability. If it is above the lower limit, it becomes easier to commercialize from both a manufacturing and application perspective.

[0057] The solid content concentration of the polyester resin aqueous dispersion of the present invention is preferably 15 to 60%. Below the lower limit is undesirable because it not only wastes transportation and storage costs but also consumes extra energy and time in the drying process when the aqueous dispersion is put into use. On the other hand, above the upper limit is undesirable because the viscosity of the aqueous dispersion may become very high. It is also undesirable from the viewpoint of storage stability.

[0058] This disclosure further includes adhesive compositions comprising the polyester resin aqueous dispersion of the present invention. The aforementioned polyester resin (A) has high reducing viscosity and excellent adhesive properties, and also has a high acid value, resulting in excellent dispersibility in aqueous dispersions. Therefore, the polyester resin aqueous dispersion of the present invention is suitable as an aqueous dispersion for adhesive applications.

[0059] This application claims the benefit of priority based on Japanese Patent Application No. 2024-171173, filed on 30 September 2024. The entire specification of Japanese Patent Application No. 2024-171173, filed on 30 September 2024, is incorporated herein by reference.

[0060] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by the following examples, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention. In the following, unless otherwise specified, "parts" means "parts by mass" and "%" means "percent mass".

[0061] <Evaluation of prepolymers and polyester resins> (1) The resin composition samples were alkaline-decomposed with sodium hydroxide in a mixed solvent of deuterium methanol / dimethyl sulfoxide-d6, and the decomposition solution was diluted with heavy water. Nuclear magnetic resonance (NMR) spectrometer (Bruker "AVANCE NEO 600") and data processing were performed using Bruker TopSpin® 4.0 software. １¹H-NMR measurements were performed. The measurements were conducted under the following conditions: resonance frequency of 600 MHz, waiting time of 1 sec, number of integrations of 64, measurement temperature of 303 K, and a reference level of heavy water at 4.74 ppm. The resin composition was calculated in moles from the integral ratio. The integral value of the terephthalic acid peak detected at 7.89 ppm was set to 100. Note that even if the monomer is not terephthalic acid (for example, isophthalic acid or orthophthalic acid), if the position of the proton peak in NMR is clear, it can be used as a reference for the resin composition, and in that case, the integral value of the proton peak of that monomer can be set to 100. The same applies to the "content of TMA triester compounds" described later.

[0062] (2) Reduced viscosity (ηsp / c) 0.1 g of the sample was dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 6 / 4), and measured at 30°C using an Ubbelohde viscometer.

[0063] (3) The GPC sample was dissolved or diluted in tetrahydrofuran to a sample concentration of approximately 0.5%, and filtered through a polytetrafluoroethylene membrane filter with a pore size of 0.5 μm to be used as the measurement sample. The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the sample were measured by gel permeation chromatography using tetrahydrofuran as the mobile phase and a differential refractometer as the detector, and the degree of dispersion (Mw / Mn) was calculated. The flow rate was 1 mL / min and the column temperature was 30°C. Showa Denko "KF-802", "KF-804L", and "KF-806L" columns were used. Monodisperse polystyrene was used as the molecular weight standard.

[0064] (4) Hydroxyl Value (OHV) The sample was dissolved in chloroform-d alone and in a mixed solvent of chloroform-d and trifluoroacetic acid, and nuclear magnetic resonance (NMR) was performed using a Bruker AVANCE NEO 600 and Bruker TopSpin® 4.0 software for data processing, using each solvent. １ ¹H-NMR measurements were performed, the integral values ​​were determined, and the hydroxyl value was calculated by averaging these values.

[0065] (5) Glass transition temperature (Tg) was measured using a differential scanning calorimeter (SII "DSC-200"). 5 mg of the sample was placed in an aluminum container with a retaining lid and sealed. It was cooled to -50°C using liquid nitrogen, and then heated to 150°C at a rate of 20°C / min. In the endothermic curve obtained during this process, the temperature at the intersection of the baseline before the endothermic peak and the tangent line toward the endothermic peak was defined as the glass transition temperature.

[0066] (6) Amount of unreacted TMA: 160 mg of the aqueous dispersion was dried under vacuum at 105°C for 3 hours to obtain a polyester resin. The resin was dissolved in chloroform, and then low-moisture methanol was added and allowed to stand for 36 hours to methylate the anhydrous ring. The supernatant was filtered through a PTFE filter, and the dried residue was dissolved in DMAc. The sample was analyzed using a Shimadzu HPLC to identify the amount of unreacted TMA in the aqueous dispersion. Column: Inertsil ODS-2 5 μm 4.0 mm × 250 mm Mobile phase: A 0.4% phosphoric acid, B acetonitrile Flow rate: 1.0 mL / min Injection volume: 10 μL Detection wavelength: 258 nm

[0067] (7) Samples containing the triester compound of TMA were dissolved in a mixed solvent of chloroform-d / 1,1,1,3,3,3-Hexafluoro-2-propanol-d2 / triethylamine (90 / 10 / 1), and nuclear magnetic resonance (NMR) was performed using a Bruker AVANCE NEO 600 spectrometer and Bruker TopSpin® 4.0 software for data processing. １ 1H-NMR and TOCSY spectral measurements were performed. １ The 1H-NMR measurements were performed under the following conditions: resonance frequency of 600.13 MHz, waiting time of 1 sec, number of integrations of 64, measurement temperature of 303 K, and reference level of chloroform at 7.33 ppm. １When the integral value of TPA detected at 8.12 ppm in 1H-NMR was set to 100, the integral value of the peak detected at 7.75–7.85 ppm was defined as Hc. Measurement by the TOCSY method was performed under the following conditions: resonance frequency 600.13 MHz, waiting time 2 sec, pulse width 2.5 msec, mixing time 0.05 sec, number of integrations 16 times, measurement temperature 303 K, and reference chloroform 7.3 ppm. The integral values ​​of the peaks observed at (F1 axis, F2 axis) = (7.8, 8.2) and (7.8, 8.1) in the TOCSY spectrum were defined as Ha and Hb, respectively, and X was calculated using the following formula, with (1) composition mol ratio of terephthalic acid obtained from the resin composition: Hd. Hc is the integral value including components derived from the triester of TMA. By measuring using the TOCSY method, the Hc component is separated into Ha and Hb, and Ha is the integral value containing only the triester. X = Hd / 100 × 4 × Hc × (Ha / (Ha + Hb)) Let X be the content (mol%) of the triester of TMA.

[0068] (8) Acid value (AV) 0.2 g of the sample was dissolved in 20 ml of chloroform and titrated with a methanol solution of 0.1 N sodium methoxide in the presence of phenolphthalein indicator. The point at which the solution turned red was defined as the neutralization point, and the value was converted to the equivalent amount per ton of sample (eq / t).

[0069] (9) Acid value (AV) derived from dicarboxylic acid components ｄ The sample was dissolved in a mixed solvent of chloroform-d / 1,1,1,3,3,3-Hexafluoro-2-propanol-d2 / triethylamine, and nuclear magnetic resonance (NMR) was performed using a Bruker AVANCE NEO 600 spectrometer and Bruker TopSpin® 4.0 software for data processing. １ 1H-NMR measurements were performed, and the content derived from the dicarboxylic acid component was determined from the integrated value, which was then converted into an acid value per ton of sample.

[0070] (10) Acid value (AV) of the diester compound ２ )・Acid value (AV) of monoester compounds １ ) Since direct measurement is difficult, the acid value (AV) can be calculated using the following formulas (A) to (D). ２ ) and acid value (AV１ was determined. First, the following formula (A) holds for the acid value of the polyester resin. The acid value (AV) of the polyester resin = the acid value (AV ２ ) of the diester form of TMA + the acid value (AV １ ) of the monoester form of TMA + the acid value (AV ｄ ) derived from the dicarboxylic acid component + the acid value (AV ｕ ) derived from unreacted TMA... (A) Next, focusing on the ester structure of the TMA component, the following formula (B) holds. The content (W) of the TMA component = the content (W ３ ) of the triester form of TMA + the content (W ２ ) of the diester form of TMA + the content (W １ ) of the monoester form of TMA + the amount of unreacted TMA (W ｕ )... (B) Also, since there is one free carboxy group in one diester form of TMA and two free carboxyl groups in one monoester form of TMA, considering the molecular weight of TMA of 192.13, the following relationships of formulas (C) to (D) hold between the acid value and the content. The acid value (AV ２ ) of the diester form = 10 ６ ×{(W ２ + W １ ) / 100} / 192.13 × {W ２ / (W ２ + W １ )}... (C) The acid value (AV １ ) of the monoester form = 10 ６ ×{(W ２ + W １ ) / 100} / 192.13 × {W １ / (W ２ + W １ )} × 2... (D) In formula (A), AV and AV ｄ shall use the above-mentioned measurement results, and AV ｕ shall use the result obtained by converting the result of "(6) Amount of unreacted TMA" to the acid value per ton of sample. These units are eq / t. In formula (B), W ３ is "(7) Content of the triester form of TMA", W ｕUse the result of “(6) Amount of unreacted TMA”, and use the total amount of TMA components determined by “(1) Resin composition” for W. Make sure their units are the same. Then AV, AV ２ , AV １ , AV ｄ , AV ｕ , W, W ３ , W ２ , W １ and W ｕ Among the 10 variables of, 6 variables can be directly obtained. For the 4 unknown variables, since the four equations of formulas (A) to (D) hold, AV, ２ and AV １ are calculated.

[0071] (11) Amount of metal component The amount of metal component contained in the metal component aqueous dispersion was determined based on the following procedure. Weigh the polyester resin obtained by drying the aqueous dispersion in a platinum crucible under vacuum at 105 °C for 3 hours, carbonize it on an electric stove, and then ashing it in a muffler furnace at 550 °C for 8 hours. Dissolve the ashed sample in 1.2 M hydrochloric acid to obtain a sample solution. Measure the prepared sample solution under the following conditions, and determine the concentrations of antimony element, titanium element, and zinc element in the polyester resin by high-frequency inductively coupled plasma optical emission spectrometry. Apparatus: CIROS-120 manufactured by SPECTRO Plasma output: 1400 W Plasma gas: 13.0 L / min Auxiliary gas: 2.0 L / min Nebulizer: Cross-flow nebulizer Chamber: Cyclone chamber Measurement wavelength: 167.078 nm

[0072] <Evaluation of polyester resin aqueous dispersion> (12) Dispersibility The particle size of the aqueous dispersion was evaluated using a concentrated particle size analyzer (“FPAR-1000” manufactured by Otsuka Electronics Co., Ltd.). The particle size was analyzed by histogram analysis. ○: The average particle size is 200 nm or less. ×: The average particle size exceeds 200 nm, or it cannot be dispersed and precipitates.

[0073] (13) After the storage-stable aqueous dispersion was left to stand in a constant temperature incubator at 25°C for 3 months, the particle size of the aqueous dispersion was evaluated in the same manner as in the previous section. ○: (Average particle size after stability test) - (Average particle size before stability test) ≤ 100 nm ×: (Average particle size after stability test) - (Average particle size before stability test) > 100 nm, or precipitation occurs in the aqueous dispersion after stability test.

[0074] (14) Adhesion Aqueous dispersion was applied to a 25 μm thick A-PET film to a thickness of 3-4 μm. It was then dried at 140°C for 30 seconds to obtain a laminated film. The coated surface of the evaluation laminated film was heat-sealed to a 25 μm thick A-PET film at a temperature of 150°C and a pressure of 0.2 MPa for 1 second. A 15 mm wide test piece was then cut out, and a 180° peel test was performed at 25°C using a Shimadzu Autograph AG-Xplus at a tensile speed of 200 mm / min to measure the peel strength. ・For aqueous dispersions containing polyester resin with Tg ≥ 50°C ○: Peel strength is 6 N / 15 mm or more ×: Peel strength is less than 6 N / 15 mm ・For aqueous dispersions containing polyester resin with Tg < 50°C ○: Peel strength is 2 N / 15 mm or more ×: Peel strength is less than 2 N / 15 mm

[0075] <Example 1> In a 3 L four-necked flask, 315 parts terephthalic acid, 444 parts isophthalic acid, 368 parts ethylene glycol, 333 parts neopentyl glycol, and 0.2 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. After that, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 90 minutes to carry out later polymerization, thereby polymerizing the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 28 parts trimellitic anhydride (TMA) was added under a nitrogen atmosphere at 240-250°C and stirred for 60 minutes. Then, the pressure was reduced again to below 1 mmHg and polymerization was carried out at 250°C for 60 minutes. After that, the vacuum was broken and stirred under a nitrogen atmosphere for 1 hour. After that, it was removed into a water bath to obtain a polyester resin. The composition and various properties of the final obtained polyester resin are shown in Tables 1 to 3.

[0076] 105 parts of the obtained polyester resin, 105 parts of methyl ethyl ketone, and 35 parts of isopropanol were placed in a 1 L flask. The mixture was heated to 75°C and stirred for 3 hours until completely dissolved. After confirming dissolution, 2.8 parts of N,N-dimethylethanolamine were added and stirred for 30 minutes. Then, 245 parts of pure water were slowly added dropwise, and the mixture was heated to 90°C and stirred until the distillate was gone. The mixture was then filtered through a 200 μm nylon mesh to obtain an aqueous dispersion of polyester resin.

[0077] <Example 2> In a 3 L four-necked flask, 411 parts terephthalic acid, 367 parts orthophthalic acid, 565 parts 1,2-propanediol, and 0.2 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. Subsequently, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 90 minutes to carry out final polymerization, thereby polymerizing the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 50 parts TMA was added under a nitrogen atmosphere at 240-250°C and stirred for 60 minutes. A polyester resin aqueous dispersion was obtained in the same manner as in Example 1.

[0078] <Example 3> In a 3 L four-necked flask, 289 parts terephthalic acid, 217 parts isophthalic acid, 264 parts sebacic acid, 351 parts ethylene glycol, 317 parts neopentyl glycol, and 0.2 parts tetra-n-butyl titanate were charged. The temperature was then gradually raised to 250°C over 4 hours to carry out the esterification reaction. A polyester resin aqueous dispersion was obtained in the same manner as in Example 1.

[0079] <Example 4> In a 3 L four-necked flask, 555 parts isophthalic acid, 209 parts adipic acid, 267 parts ethylene glycol, 339 parts 1,6-hexanediol, and 0.2 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. Subsequently, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 90 minutes to carry out final polymerization, thereby polymerizing the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 48 parts TMA was added under a nitrogen atmosphere at 240-250°C and stirred for 60 minutes. A polyester resin aqueous dispersion was obtained in the same manner as in Example 1.

[0080] <Example 5> In a 3 L four-necked flask, 224 parts terephthalic acid, 523 parts isophthalic acid, 126 parts ethylene glycol, 365 parts 1,4-butanediol, 97 parts cyclohexanedimethanol, and 0.2 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. Subsequently, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 90 minutes to carry out final polymerization, thereby polymerizing the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 46 parts TMA were added under a nitrogen atmosphere at 240-250°C and stirred for 60 minutes. A polyester resin aqueous dispersion was obtained in the same manner as in Example 1.

[0081] <Example 6> In a 3 L four-necked flask, 360 parts terephthalic acid, 339 parts franzicarboxylic acid, 121 parts ethylene glycol, 338 parts neopentyl glycol, 188 parts cyclohexanedimethanol, and 0.2 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. Subsequently, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 90 minutes to carry out later polymerization, thereby polymerizing the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 44 parts TMA was added under a nitrogen atmosphere at 240-250°C and stirred for 60 minutes. A polyester resin aqueous dispersion was obtained in the same manner as in Example 1.

[0082] <Example 7> In a 3 L four-necked flask, 155 parts terephthalic acid, 258 parts isophthalic acid, 358 parts dimer acid, 212 parts ethylene glycol, 227 parts neopentyl glycol, 90 parts cyclohexanedimethanol, and 0.2 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. Subsequently, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 90 minutes to carry out later polymerization, thereby polymerizing the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 45 parts TMA was added under a nitrogen atmosphere at 240-250°C and stirred for 60 minutes. A polyester resin aqueous dispersion was obtained in the same manner as in Example 1.

[0083] <Example 8> In a 3 L four-necked flask, 427 parts terephthalic acid, 285 parts isophthalic acid, 186 parts ethylene glycol, 196 parts 1,2-propanediol, 185 parts cyclohexanedimethanol, 260 parts dimergol, and 0.2 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. Subsequently, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 90 minutes to carry out later polymerization, thereby polymerizing the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 15 parts TMA was added under a nitrogen atmosphere at 240-250°C and stirred for 60 minutes. A polyester resin aqueous dispersion was obtained in the same manner as in Example 1.

[0084] <Comparative Example 1> In a 3 L four-necked flask, 304 parts terephthalic acid, 410 parts orthophthalic acid, 18 parts TMA, 714 parts 1,2-propanediol, and 0.1 parts antimony trioxide were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. After that, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 120 minutes to carry out later polymerization to polymerize the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 27 parts TMA was added under a nitrogen atmosphere at 230°C and stirred for 30 minutes. After that, it was removed into a water bath to obtain a polyester resin. Using the obtained polyester resin, a polyester resin aqueous dispersion was obtained in the same manner as in Example 1.

[0085] <Comparative Example 2> In a 3 L four-necked flask, 382 parts terephthalic acid, 382 parts isophthalic acid, 278 parts ethylene glycol, 251 parts neopentyl glycol, and 0.1 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. After that, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 120 minutes to carry out later polymerization to polymerize the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 21 parts pyromellitic anhydride was added under a nitrogen atmosphere at 200°C and stirred for 30 minutes. After that, it was removed into a water bath to obtain a polyester resin. Using the obtained polyester resin, a polyester resin aqueous dispersion was obtained in the same manner as in Example 1.

[0086] <Comparative Example 3> A polyester resin was obtained in the same manner as in Example 1, except that the amount of TMA added was changed to 5 parts and the catalyst to 0.2 parts zinc acetate (dihydrate). An aqueous dispersion of polyester resin was obtained using the obtained polyester resin in the same manner as in Example 1.

[0087] <Comparative Example 4> A polyester resin aqueous dispersion was obtained in the same manner as in Example 1, except that the vacuum polymerization after TMA addition was carried out at 210°C.

[0088]

[0089]

[0090]

[0091] In Tables 1-3, abbreviations are used with the following meanings: "TPA": Terephthalic acid "IPA": Isophthalic acid "OPA": Orthophthalic acid "AA": Adipic acid "SA": Sebacic acid "FDCA": Frangicarboxylic acid "DA": Dimer acid "TMA": Trimellitus anhydride "PMDA": Pyromellitic anhydride "EG": Ethylene glycol "NPG": Neopentyl glycol "PG": 1,2-Propanediol "BD": 1,4-Butanediol "HD": 1,6-Hexanediol "CHDM": Cyclohexanedimethanol "DD": Dimerdiol "Ti": Titanium "Sb": Antimony "Zn": Zinc

Claims

1. The reduced viscosity of polyester resin (A) is 0.50 dl / g or higher, the acid value (AV) of polyester resin (A) is 100 eq / t or higher, and the acid value (AV) of the carboxyl group belonging to the tricarboxylic acid component is such that two carboxyl groups form an ester bond and one carboxyl group is present in a free carboxyl group state. ２ A polyester resin aqueous dispersion characterized by containing a polyester resin (A) having a concentration of 70 eq / t or more.

2. The aqueous polyester resin dispersion according to claim 1, wherein the amount of unreacted tricarboxylic acid monomer is 1000 ppm or less.

3. The polyester resin aqueous dispersion according to claim 1, wherein the content of the tricarboxylic acid component in which three carboxyl groups in the polyester resin (A) form an ester bond is 2.0 mol% or less with respect to the total amount of polycarboxylic acid constituting the polyester resin (A).

4. The polyester resin aqueous dispersion according to claim 1, wherein the antimony and zinc content is 200 ppm or less.

5. The polyester resin aqueous dispersion according to claim 1, wherein the polyester resin (A) comprises one or more dicarboxylic acid components selected from the group consisting of aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids.

6. The polyester resin aqueous dispersion according to claim 1, wherein the weight-average molecular weight (Mw) of the polyester resin (A) is 20,000 to 300,000.

7. The polyester resin aqueous dispersion according to claim 1, wherein the polycarboxylic acid component constituting the polyester resin (A) is 6 mol% or less of the polycarboxylic acid component with a tetravalent or higher valency in 100 mol%.

8. The polyester resin aqueous dispersion according to claim 1, wherein the solid content concentration of the polyester resin (A) in the polyester resin aqueous dispersion is 10 to 45% by mass.

9. The polyester resin aqueous dispersion according to claim 1, wherein the content of the polyester resin (A) in 100% by mass of the resin contained in the polyester resin aqueous dispersion is 20% by mass or more.

10. The polyester resin aqueous dispersion according to claim 1, wherein the content of an organic solvent is 30% by mass or less of 100% by mass of the polyester resin aqueous dispersion.

11. An adhesive composition comprising a polyester resin aqueous dispersion according to any one of claims 1 to 10.

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