JP2009007548A - Copolyester resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copolyester resin which has a high refractive index, an excellent coated film toughness and has both solubility in common organic solvents and dispersibility in water. <P>SOLUTION: The copolyester resin includes at least a dicarboxylic acid component having a naphthalene skeleton and a glycol component having a bis-phenol A skeleton as the copolymer components. Preferably, not less than 50 mole% of the dicarboxylic acid component having a naphthalene skeleton in the total acid components and not less than 50 mole% of the glycol component having a bis-phenol A skeleton in the total glycol components are copolymerized. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polyester resin for optical films, a coating agent, a copolyester resin that can be used as an adhesive, and a high-transparency, high-refractive index property, high Tg, and excellent bending resistance. An organic solvent solution and an aqueous dispersion are provided.

  In recent years, with the advancement of IT technology, the development of display-related display substrates has been remarkable. For example, anti-reflection film for LCD and CRT displays, base film for touch panel used in various OA equipment, prism lens sheet used for LCD backlight unit, and equipment film for electronic paper. Excellent mechanical properties and dimensional stability And transparency are required. Biaxially oriented polyester films, in addition to such properties, are excellent in electrical properties, heat resistance, and chemical resistance, and thus are frequently used in optical applications in recent years. However, since the biaxially oriented polyester film represented by PET is generally highly crystalline, it has poor adhesion to various paints, adhesives, inks, etc., and the resin itself has high crystallinity and is an organic solvent. It has the disadvantage that it cannot be used as a coating agent or an adhesive prepared in a solution or water dispersion. For such problems, Patent Document 1 proposes forming a copolyester resin layer having optical characteristics with a high refractive index by coating, and various acid components, glycols constituting the copolyester resin. Ingredients are introduced. Specific examples of the copolymer composition include terephthalic acid, isophthalic acid, trimellitic acid, sebacic acid as the acid component in the examples, and a refractive index of 1.57 consisting of ethylene glycol, neopentyl glycol, and 1,4-butanediol as the glycol component. Examples include copolymer polyesters, terephthalic acid, 5-Na sulfoisophthalic acid as an acid component, and ethylene polyester and diethylene glycol as glycol components, and a refractive index of 1.59.

  In order to obtain a clear image, the optical material is required to have a high refractive index. A material having a high refractive index has been applied to a lens or the like in the past because the aberration of transmitted light is low and can be suppressed. The refractive index of a polymer is closely related to its molecular structure and is related to the polarizability, which is a measure of electrical strain such as electronic polarization and dipole polarization in the molecule that occurs when light strikes a substance. . In general, it is known that high polarizability can be achieved by incorporating an aromatic ring, bromine, sulfur or the like in the molecule. As the literature value, polymethylmethacrylate has a refractive index of 1.489, whereas polyethylene terephthalate has 1.576, and polystyrene has 1.591.

  Examples of Patent Documents 2 and 3 exemplify unsaturated polyester obtained from an aromatic diol having a bromine atom and an unsaturated carboxylic acid, and the raw material having bromine is useful for obtaining a high refractive index material. It is suggested to be a material. On the other hand, however, halogen-based materials containing bromine and the like are being avoided from environmental problems. Patent Documents 4 and 5 propose polyesters using a special diol having a fluorene skeleton. However, such a copolyester has a high melt viscosity, it is difficult to achieve a high molecular weight, and the raw materials are also expensive. Further, Patent Document 6 proposes a polyester resin having a thioester bond and / or a sulfide group, and it is shown that they are excellent in optical characteristics and mechanical characteristics and thermal characteristics. However, most of the refractive index values are less than 1.60, and the raw materials used are low in versatility and expensive.

JP 2004-107627 A JP-A-5-331272 JP-A-6-32846 JP-A-6-184288 JP-A-8-109249 JP 2003-2962 A

  The present invention does not contain a halogen atom, which is said to be an environmental problem, uses a relatively versatile raw material, has a high glass transition temperature and is not brittle, a high refractive index polyester resin, and an organic solvent solution or an aqueous dispersion thereof Is to provide.

  As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the present invention is achieved by a copolyester resin containing a dicarboxylic acid component having a naphthalene skeleton and a glycol component having a bisphenol A skeleton as copolymerization components.

  The copolyester resin of the present invention contains a naphthalene skeleton and a bisphenol A skeleton as main components, so that it has a feature of having a high glass transition temperature, a resin property without brittleness, and a high refractive index. In addition, solubility in general-purpose organic solvents is improved. Furthermore, by copolymerizing an appropriate amount of polyalkylene ether, the melt viscosity at the time of the polymerization reaction is lowered, and it becomes possible to further increase the molecular weight, thereby obtaining a resin having less brittleness, that is, a tough resin.

  The polyester resin of the present invention can be synthesized by a conventionally well-known method. For example, a mixture of various dicarboxylic acid dialkyl ester compounds mainly composed of a dialkyl ester compound of naphthalenedicarboxylic acid and a glycol component mainly composed of an alkylene oxide adduct to an excess equivalent of bisphenol A are transesterified. Then, a method of polymerizing under a high temperature and high vacuum, or a method of esterifying a dibasic acid component mainly composed of naphthalenedicarboxylic acid and an excessive amount of a glycol component and then performing a polymerization reaction under a high temperature and high vacuum. Can be mentioned. As the polymerization catalyst, commonly used compounds such as titanium, zinc, antimony, magnesium, germanium, and aluminum can be used.

  The polyester resin of the present invention has a dicarboxylic acid component having a naphthalene skeleton of 50 mol% or more of the total acid component and a glycol component having a bisphenol A skeleton when the total is 100 mol% for each acid component and glycol component. It is preferable that 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more, and still more preferably 85 mol% or more are copolymerized in all glycol components. If the dicarboxylic acid component having a naphthalene skeleton in the acid component is less than 50 mol%, a high glass transition temperature and a high refractive index characteristic may not be obtained. On the other hand, if the glycol component having a bisphenol A skeleton is less than 50 mol% in the total glycol component, it may be difficult to achieve both high glass transition temperature and brittle resin properties, and the solubility in general-purpose organic solvents will decrease. Sometimes.

  Examples of the dicarboxylic acid having a naphthalene skeleton used in the polyester resin of the present invention include 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, and alkyl ester derivatives and anhydrides thereof. Although it can be used, 2,6-naphthalenedicarboxylic acid and its alkyl ester derivatives are preferred from the viewpoint of versatility and physical properties of the obtained resin. When the copolymerization amount of 1,4-type and 1,2-type isomers increases, the toughness of the resulting polyester resin tends to decrease.

  As the acid component other than the dicarboxylic acid having a naphthalene skeleton used in the polyester resin of the present invention, the compound preferably copolymerized at a ratio of less than 50 mol% in the total acid component includes terephthalic acid, isophthalic acid, orthophthalic acid. Aromatic dibasic acids such as acids, aliphatic dibasic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanoic acid, 1,2-cyclohexanedicarboxylic acid, 1,3- Examples include alicyclic dibasic acids such as cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. Of these dibasic acids, polyester resins from which terephthalic acid and isophthalic acid can be obtained are preferred because of reduced physical properties.

  Examples of the glycol compound having a bisphenol A skeleton used in the polyester resin of the present invention include alkylene oxide adducts such as an ethylene oxide adduct and a propylene oxide adduct to bisphenol A. Of these, ethylene oxide adducts and propylene oxide adducts to bisphenol A are preferred from the viewpoint of enhancing the effects of the present invention by introducing a large amount of bisphenol A skeleton into the polyester resin.

Examples of the glycol component other than glycol having a bisphenol A skeleton used in the polyester resin of the present invention preferably in a proportion of less than 50 mol% in the total glycol component include, for example, ethylene glycol, 1,2-propylene glycol, 1,3. -Propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 2-methyl-1,3-propylene glycol, neopentyl glycol, 3-methyl -1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,2 -Dimethyl-3-hydroxypropyl-2 ', 2'-dimethyl-3-hydroxy Propanate, 2-n-butyl-2-ethyl-1,3-propanediol, 3-ethyl-1,5-pentanediol, 3-propyl-1,5-pentanediol, 2,2-diethyl-1,3 -Aliphatic diols such as propanediol, 3-octyl-1,5-pentanediol, 1,3-bis (hydroxymethyl) cyclohexane, 1,4-bis (hydroxymethyl) cyclohexane, 1,4-bis ( Hydroxyethyl) cyclohexane, 1,4-bis (hydroxypropyl) cyclohexane, 1,4-bis (hydroxymethoxy) cyclohexane, 1,4-bis (hydroxyethoxy) cyclohexane, 2,2-bis (4-hydroxymethoxycyclohexyl) Propane, 2,2-bis (4hydroxyethoxycyclohexyl) propane Bis (4-hydroxycyclohexyl) methane, 2,2-bis (4-hydroxycyclohexyl) propane, 3 (4), 8 (9) -tricyclo [5.2.1.0 ^2,6 ] decanedimethanol, etc. And alicyclic glycols. Among these glycol compounds, when ethylene glycol and / or 1,2-propylene glycol and / or 1,3-propylene glycol are allowed to coexist as a component in the glycol component of the polyester resin of the present invention during the polymerization reaction, The polymerization reaction of the polyester resin proceeds smoothly and a polyester resin having a high molecular weight is easily obtained. However, in order to maintain a high refractive index, the copolymerization amount of ethylene glycol, 1,2-propylene glycol, and 1,3-propylene glycol is preferably less than 15 mol% in the polyester resin.

  In addition to the above acid component and glycol component, the polyester resin of the present invention is copolymerized within a range in which a polyfunctional carboxylic acid such as trimethylolpropane and trimellitic anhydride and a polyester resin that produces an alcohol compound do not gel, It is also possible to facilitate the molecular weight.

  In addition to the above raw materials, the polyester resin of the present invention is copolymerized with 5-Na sulfoisophthalic acid, 2-Na sulfoterephthalic acid and their dialkyl ester derivatives as acid components to prepare an aqueous dispersion of the obtained polyester resin. I can do it. It is preferable that the copolymerization amount in that case exists in the range of 0.2-10 mol% in an acid component. In addition, polyalkylene glycol can be copolymerized with the polyester resin of the present invention as long as the physical properties of the resulting polyester resin do not deteriorate. Examples of specific compounds include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like. These polyether glycols have the effect of lowering the melt viscosity of the resulting polyester resin and facilitating higher molecular weight. Moreover, the softness | flexibility can be provided to the obtained polyester resin, and the effect which reduces a brittleness can be anticipated. Of these polyoxyalkylene glycols, polyethylene glycol is preferred in terms of imparting hydrophilicity to the polyester resin and facilitating the formation of an aqueous dispersion.

  The number average molecular weight of the polyalkylene glycol is 1000 to 6000, more preferably 2000 to 4000. When the molecular weight is less than 1000, the compatibility between the alkyl ether component and the other copolymer component is good, and the glass transition temperature is greatly lowered by the copolymerization, and the resin specific gravity is lowered. As a result, the refractive index tends to be lowered. On the other hand, when the molecular weight exceeds 6000, copolymerization becomes difficult, and it may be difficult to obtain a uniform polymer. Further, the copolymerization weight ratio is 0.5 to 5 mol%, more preferably 1 to 4.5 mol%, further preferably 1.2 to 4.2 mol%, and next preferably 1.5 to 4 mol%. Most preferably, it is 2.5 to 3.5 mol%. If it is less than 0.5 mol%, the effect of lowering the melt viscosity at the time of the polymerization reaction by copolymerization is insufficient, and if it exceeds 5 mol%, the glass transition temperature of the whole polymer is greatly lowered, and the resin specific gravity is lowered. The refractive index will also decrease.

  The polyester resin of the present invention preferably has an aromatic ring in the side chain of the polyester skeleton from the viewpoint of further improving the refractive index and improving the storage stability of the dispersion when converted to an aqueous dispersion. As a method for introducing a skeleton into the side chain, a method in which 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is copolymerized with dicarboxylic acid condensed with itaconic acid, 1,2-diphenylsuccinic acid Are known, and a method of copolymerizing phenyl glycidyl ether is known. In particular, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 from the viewpoint of function expression efficiency with respect to the copolymerization amount. It is preferred to use a dicarboxylic acid in which the oxide is condensed with itaconic acid. The preferable copolymerization amount in this case is 20-30 mol%. If it is less than 20 mol%, the effect of improving the refractive index may be insufficient, and if it exceeds 30 mol%, the physical properties of the produced polyester resin may be lowered. A conventionally known method for producing such a polyester resin can be used, and for example, a method described in JP-A-2004-43535 can also be used.

  In the polyester resin of the present invention, inorganic fine particles can be blended within the range in which the coating film physical properties of the polyester resin are not lowered in order to further improve the refractive index. Specific examples of the inorganic fine particles include titanium-based, zirconia-based, and silica-based particles.

  The polyester resin of the present invention can be used as a coating material or an adhesive by making an aqueous dispersion or an organic solvent-dissolved product by a conventionally known method.

  Although it does not specifically limit as a solvent to be used, For example, toluene, xylene, C7-20 hydrocarbon, cyclohexanone, cyclopentanone, cyclohexane, cyclopentane, n-hexane, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, N, N- Examples include dimethylformamide, N-methyl-2-pyrrolidone, ethyl acetate, propyl acetate, isophorone, methanol, ethanol, butanol and the like. Of these, toluene, xylene, hydrocarbons having 7 to 20 carbon atoms, cyclohexanone, cyclopentanone, cyclohexane, cyclopentane, n-hexane, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, N, N-dimethylformamide, N-methyl 2-Pyrrolidone, ethyl acetate, propyl acetate and isophorone are preferred. Further, when considering the heat resistance of the substrate, coating suitability, etc., toluene, xylene, cyclohexanone, cyclopentane, methyl ethyl ketone, methyl isobutyl ketone, and ethyl acetate are more preferable.

  The production of the aqueous dispersion uses a known method such as a direct emulsification method using an amphiphilic solvent, a method of adding water after dissolving in an organic solvent in advance, and a solvent replacement method of distilling off the solvent therefrom. Can do.

  The polyester resin aqueous dispersion of the present invention may contain various amphiphilic solvents as necessary. Examples of the amphiphilic solvent include n-butanol, isopropyl alcohol, diacetone alcohol, 2-ethylhexanol, methyl ethyl ketone, acetonitrile, dimethylacetamide, dimethylformamide, n-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, 1,3- Dioxane, 1,3-oxolane, methyl cellosolve, ethyl cellosolve, n-butyl cellosolve, t-butyl cellosolve, ethyl carbitol, butyl carbitol, propylene glycol monopropyl ether, propylene glycol monobutyl ether and the like can be used. Of these, butyl cellosolve, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and butyl carbitol are particularly preferred. As the amphiphilic solvent, it is preferable to use 20% or less of the entire aqueous dispersion when the resin solid content concentration is 30%. From the viewpoint of organic solvent reduction, 10% or less is particularly preferable. An amphiphilic solvent has an effect that workability at the time of preparing an aqueous dispersion is improved, or a coating agent or an adhesive containing it has an excellent applicability.

  In producing the polyester resin aqueous dispersion of the present invention, the carboxyl group introduced into the polyester resin by addition reaction, depolymerization reaction or the like of the acid anhydride compound may be neutralized with a basic compound. As the basic compound to be used, a compound that volatilizes by drying at the time of forming a coating film is preferable as the basic compound, and examples thereof include a method using ammonia and / or an organic amine compound having a boiling point of 250 ° C. or less. Preferably, for example, 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 and the like. These basic compounds require an amount that can be at least partially neutralized with respect to the acid value of the polyester resin. Specifically, it is desirable to add 0.5 to 1.5 equivalents with respect to the acid value. When the amount is less than 0.5 equivalent, the effect of dispersing in water is low, and when the amount exceeds 1.5 equivalent, the polyester resin aqueous dispersion may be significantly thickened or the polyester may be hydrolyzed.

  When the polyester resin of the present invention is used as a coating material or an adhesive, it may be used in combination with a conventionally known curing agent. That is, alkyl etherified amino formaldehyde resins, epoxy compounds and isocyanate compounds, alkyl etherified phenol resins, and the like can be mentioned.

  The alkyl etherified aminoformaldehyde resin is, for example, formaldehyde or paraformaldehyde alkylated with an alcohol having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, n-butanol, urea, N, N -Condensation products with ethylene urea, dicyandiamide, aminotriazine, etc., and methoxylated methylol-N, N-ethyleneurea, methoxylated methylol dicyandiamide, methoxylated methylol benzoguanamine, butoxylated methylol benzoguanamine, methoxylated methylol melamine, butoxylated Examples include methylol melamine, methoxylated / butoxylated mixed methylol melamine, and butoxylated methylol benzoguanamine.

  Examples of epoxy compounds include diglycidyl ether of bisphenol A and oligomers thereof, diglycidyl ether of hydrogenated bisphenol A and oligomers thereof, orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, and p-oxybenzoic acid diglyceride. Glycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1 4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene Cole diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidyl propylene urea, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether , Pentaerythritol tetraglycidyl ether, triglycidyl ether of glycerol alkylene oxide adduct, and the like.

  Furthermore, the isocyanate compound includes aromatic and aliphatic diisocyanates, and trivalent or higher polyisocyanates, which may be either low molecular compounds or high molecular compounds. For example, tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate or trimers of these isocyanate compounds, and excess of these isocyanate compounds Amount of low molecular active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine or various polyester polyols, polyether polyols, polyamides Against high molecular active hydrogen compounds It includes terminal isocyanate group-containing compounds obtained by.

  The isocyanate compound may be a blocked isocyanate. As the isocyanate blocking agent, for example, phenols such as phenol, thiophenol, methylthiophenol, ethylthiophenol, cresol, xylenol, resorcinol, nitrophenol, chlorophenol, oximes such as acetoxime, methylethyl ketoxime, cyclohexanone oxime, methanol, Alcohols such as ethanol, propanol and butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; tertiary alcohols such as t-butanol and t-pentanol; Examples include lactams such as caprolactam, δ-valerolactam, γ-butyrolactam, β-propylolactam, and other aromatic amines, imides, acetylacetate. , Acetoacetic ester, active methylene compounds such as malonic acid ethyl ester, mercaptans, imines, ureas, diaryl compounds, such as sodium bisulfite may also be mentioned. The blocked isocyanate can be obtained by subjecting the above isocyanate compound and an isocyanate blocking agent to an addition reaction by a conventionally known appropriate method.

  With these curing agents, known curing agents or accelerators selected according to the type can be used in combination.

  The polyester resin of the present invention preferably has a refractive index of 1.60 or more. Although an upper limit is not specifically limited, It is realistic that it is less than 1.90. The method of measuring the refractive index is the method described in the examples.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, but may be implemented with appropriate modifications within a scope that can meet the gist of the present invention. These are all included in the technical scope of the present invention.

The measurement and evaluation methods employed in this specification are as follows.
(1) Number average molecular weight
Water gel gel permeation chromatograph (GPC) 150C was used and measurement was performed at a flow rate of 1 ml / min using tetrahydrofuran as a carrier solvent. Three columns, Shodex KF-802, KF-804, and KF-806, manufactured by Showa Denko K.K., were connected as columns, and the column temperature was set to 30 ° C. A polystyrene standard was used as the molecular weight standard sample.

(2) Acid value After 0.2 g of resin was dissolved in 20 ml of chloroform, phenolphthalein was measured with a 0.1 N NaOH NaOH solution as an indicator, and the measured value was shown as equivalent to 1 ton of resin solid content.

(3) Glass transition temperature 5 mg of a sample is put in an aluminum sample pan and sealed, and the temperature is increased up to 200 ° C. at a rate of temperature increase of 20 ° C./min using a differential scanning calorimeter DSC-220 manufactured by Seiko Instruments Inc. Measured and determined at the temperature of the intersection of the baseline extension below the glass transition temperature and the tangent indicating the maximum slope at the transition.

(4) Polyester resin composition The resin was dissolved in chloroform-d, and the resin composition ratio was determined by ¹ H-NMR using a nuclear magnetic resonance analyzer (NMR) “Gemini-200” manufactured by Varian.

(5) Refractive index A cyclohexanone solution with a polyester resin solid content of 30 wt% or an aqueous dispersion with a polyester resin solid content of 27 wt% is applied to the non-corona-treated surface of an OPP (biaxially stretched polypropylene) film, and heated with hot air at 120 degrees for 30 minutes. It dried and obtained the coating film whose thickness is 10 micrometers after drying. Subsequently, the coating film was peeled from the OPP film and subjected to measurement of the refractive index. The measurement was performed using Atago Co., Ltd.'s Atsbe refractometer 4T.
The light source of the refractometer was sodium D line (wavelength: 589 nm), and methylene iodide (CP grade manufactured by Nacalai Tesque Co., Ltd.) was used as an intermediate solution. In the measurement, the refractive index (Nz) in the longitudinal direction (coating direction), the refractive index (Ny) in the width direction, and the refractive index (Nz) in the thickness direction of the film were measured, and the average value of these three measured values was used. .

(6) Toughness of the coating film As a measure for evaluating the toughness of the coating film, a bending test of the coating film was performed. Specifically, the prepared cyclohexanone solution with a polyester resin solid content of 30 wt% and an aqueous dispersion with a polyester resin solid content of 27 wt% were applied to a PET film with a thickness of 50 μm, dried with hot air at 120 degrees for 30 minutes, and the thickness after drying was 10 μm. Coating film was obtained. Next, the film was bent 180 degrees on the PET film surface side, the coating state in the refracted portion of the coating film was observed with a magnifying glass × 10 times, and the results were ranked as follows and used as evaluation criteria.
◎ ・ ・ ・ ・ ・ ・ ・ No change at all
○ ··············· There are extremely small cracks that are difficult to confirm visually.
Δ ···· Partial cracks can be visually confirmed.
× ·········································································.

(7) General-purpose solvent solubility The obtained polyester resin solid content was dissolved in cyclohexanone (100%) with heating and stirring at 90 ° C to prepare a solution having a solid content concentration of 30 wt%. The state of the solution was observed when the obtained solution was returned to room temperature and allowed to stand for 24 hours, and the following judgment was made.
····························································································· …… ..Solid solution whitening and / or solution viscosity increased compared to 24 hours before standing × ・ ・ ・ ・ ・ ・ ・ ・ Resin content and solvent separated

Hereinafter, the abbreviations of the compounds shown in the tables in the examples indicate the following compounds, respectively.
2,6NDC: 2,6-Naphthalic acid 2,3NDC: 2,3-Naphthalic acid HCA: 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide IA: Itaconic acid 5-SIP: 5Na -Sulfoisophthalic acid T: terephthalic acid I: isophthalic acid O: orthophthalic acid AA: adipic acid SCA: oxalic acid BPE: BPE-20F (manufactured by Sanyo Kasei Co., Ltd .: ethylene oxide adduct to bisphenol A)
EG: ethylene glycol NPG: neopentyl glycol DEG: diethylene glycol PEG2K: polyethylene glycol having a number average molecular weight of 2000

The synthesis example and comparative synthesis example of the polyester resin used for the Example of this invention and the comparative example are shown below.
Synthesis Example-1
Synthesis of polyester resin (A) component A 2 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 244 parts of dimethyl 2,6-naphthalate, BPE-20F (manufactured by Sanyo Kasei Co., Ltd .: Bisphenol A) 290 parts of ethylene oxide adduct), 70 parts of ethylene glycol and 0.1 part of tetrabutyl titanate (TBT) as a catalyst were charged, and the ester exchange reaction was allowed to proceed at 190 ° C. to 230 ° C. for 3 hours. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 80 minutes and the polyester resin A was obtained. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin A are shown in Table 1.

Synthesis Example-2
Synthesis of polyester resin (B) In a 2 L four-necked flask equipped with a thermometer, a stir bar and a Liebig condenser, 122 parts of dimethyl 2,6-naphthalate, 99 parts of 2,3-naphthalenedicarboxylic acid anhydride, BPE- 290 parts of 20F (manufactured by Sanyo Chemical Co., Ltd .: ethylene oxide adduct to bisphenol A), 70 parts of ethylene glycol and 0.1 part of tetrabutyl titanate (TBT) as a catalyst were charged and transesterified at 190 ° C to 230 ° C for 3 hours. The reaction was allowed to proceed. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 80 minutes and the polyester resin B was obtained. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin B are shown in Table 1.

Synthesis example-3
Synthesis of polyester resin (C) In a 2 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 232 parts of dimethyl 2,6-naphthalate, 14.8 parts of dimethyl 5-Nasulfoisophthalate, BPE- 290 parts of 20F (manufactured by Sanyo Chemical Co., Ltd .: ethylene oxide adduct to bisphenol A), 70 parts of ethylene glycol and 0.1 part of tetrabutyl titanate (TBT) as a catalyst were charged and transesterified at 190 ° C to 230 ° C for 3 hours. The reaction was allowed to proceed. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 40 minutes and the polyester resin C was obtained. Table 1 shows the composition, molecular weight, glass transition temperature, and acid value of the resulting polyester resin C.

Synthesis example 4
Synthesis of polyester resin (D) Into a 2 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 232 parts of dimethyl 2,6-naphthalate, 14.8 parts of dimethyl 5-Nasulfoisophthalate, BPE- 225 parts of 20F (manufactured by Sanyo Chemical Co., Ltd .: ethylene oxide adduct to bisphenol A), 80 parts of ethylene glycol and 0.1 part of tetrabutyl titanate (TBT) as a catalyst were charged and transesterified at 190 ° C to 230 ° C for 3 hours. The reaction was allowed to proceed. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 30 minutes and the polyester resin D was obtained. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin D are shown in Table 1.

Synthesis example-5
Synthesis of polyester resin (E) Into a 2 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 232 parts of dimethyl 2,6-naphthalate, 14.8 parts of dimethyl 5-Nasulfoisophthalate, BPE- 129 parts of 20F (manufactured by Sanyo Kasei Co., Ltd .: ethylene oxide adduct to bisphenol A), 100 parts of ethylene glycol and 0.1 part of tetrabutyl titanate (TBT) as a catalyst were charged and transesterified at 190 ° C to 230 ° C for 3 hours. The reaction was allowed to proceed. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 30 minutes and the polyester resin E was obtained. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin E are shown in Table 1.

Synthesis Example-6
Synthesis of polyester resin (F) In a 2 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 232 parts of dimethyl 2,6-naphthalate, 14.8 parts of dimethyl 5-Nasulfoisophthalate, BPE- 20F (manufactured by Sanyo Chemical Co., Ltd .: bisphenol A ethylene oxide adduct) 283 parts, ethylene glycol 70 parts, molecular weight 2000 polyethylene glycol 30 parts, and 0.1 parts of tetrabutyl titanate (TBT) as a catalyst to prevent oxidation The agent Irganox 1330 (manufactured by Ciba Specialty Chemicals Co., Ltd.) was charged in an amount of 0.6 part, and the transesterification reaction was allowed to proceed at 190 ° C to 230 ° C for 3 hours. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 80 minutes and the polyester resin F was obtained. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin F are shown in Table 1.

Synthesis Example-7
Synthesis of polyester resin (G) To a 2 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 244 parts of dimethyl 2,6-naphthalate and BPE-20F (manufactured by Sanyo Chemical Co., Ltd .: bisphenol A) Of ethylene oxide adduct of 283 parts, 70 parts of ethylene glycol, 70 parts of polyethylene glycol having a molecular weight of 2000 and 0.1 part of tetrabutyl titanate (TBT) as a catalyst and 0.6 part of antioxidant Irganox 1330 The transesterification reaction was allowed to proceed for 3 hours at ~ 230 ° C. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 80 minutes and the polyester resin G was obtained. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin G are shown in Table 1.

Synthesis Example-8
Synthesis of polyester resin (H) In a 2 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 171 parts of dimethyl 2,6-naphthalate, 14.8 parts of dimethyl 5-Nasulfoisophthalate, BPE- 20F (manufactured by Sanyo Chemical Co., Ltd .: ethylene oxide adduct to bisphenol A) 283 parts, 70 parts of ethylene glycol, 70 parts of polyethylene glycol having a molecular weight of 2000 and 0.1 part of tetrabutyl titanate (TBT) as a catalyst, antioxidant The agent Irganox 1330 was charged in an amount of 0.6 g, and the transesterification reaction was allowed to proceed at 190 ° C to 230 ° C for 3 hours. Subsequently, 32.5 g of itaconic acid, 71 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 0.1 part of tributylamine were added and the temperature was raised to 250 ° C. Polymerization was performed to obtain a polyester resin H. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin H are shown in Table 1.

Synthesis Example-9
Synthesis of polyester resin (I) In a 2 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 232 parts of dimethyl 2,6-naphthalate, 14.8 parts of 5-Na sulfoisophthalic acid, BPE-20F (Sanyo Chemicals Co., Ltd .: ethylene oxide adduct to bisphenol A) 283 parts, 70 parts of ethylene glycol, 70 parts of polyethylene glycol having a molecular weight of 2000, and 0.1 part of tetrabutyl titanate (TBT) as a catalyst and an antioxidant The transesterification reaction was allowed to proceed for 3 hours at 190 ° C to 230 ° C with 0.6 parts of Irganox 1330. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 80 minutes and the polyester resin I was obtained. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin I are shown in Table 1.

Comparative Synthesis Example-10
Synthesis of polyester resin (J) In a 2 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 244 parts of dimethyl 2,6-naphthalate, 80 parts of ethylene glycol, 73 parts of neopentyl glycol and tetra as a catalyst 0.1 part of butyl titanate (TBT) and 0.6 part of antioxidant Irganox 1330 were charged, and the ester exchange reaction was allowed to proceed at 190 ° C. to 230 ° C. for 3 hours. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 80 minutes and the polyester resin J was obtained. Table 1 shows the composition, molecular weight, glass transition temperature, and acid value of the resulting polyester resin J.

Comparative Synthesis Example-11
Synthesis of polyester resin (K) 118 parts of oxalic acid, BPE-20F (manufactured by Sanyo Chemical Co., Ltd .: ethylene oxide addition product to bisphenol A) in a 2 L four-necked flask equipped with a thermometer, stir bar, and Liebig condenser ) 290 parts, ethylene glycol 70 parts and 0.1 part of tetrabutyl titanate (TBT) as a catalyst were charged, and the esterification reaction was allowed to proceed at 190 ° C. to 230 ° C. for 3 hours. Subsequently, after heating up to 250 degreeC, it superposed | polymerized under pressure reduction for 80 minutes and the polyester resin K was obtained. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin K are shown in Table 1.

Comparative Synthesis Example-12
Synthesis of polyester resin (L) In a 1 L four-necked flask equipped with a thermometer, a stir bar, and a Liebig condenser, 58 parts of dimethyl terephthalate, 58 parts of dimethyl isophthalate, 80 parts of ethylene glycol, 73 parts of neopentyl glycol and catalyst As an example, 0.1 part of tetrabutyl titanate (TBT) was charged, and the transesterification reaction was allowed to proceed at 190 to 230 ° C. for 3 hours. Next, 58 parts of adipic acid was additionally added, the temperature was raised to 250 ° C., and polymerization was performed under reduced pressure for 80 minutes to obtain a polyester resin L. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin L are shown in Table 1.

Comparative Synthesis Example-13
Synthesis of polyester resin (M) In a 1 L four-necked flask equipped with a thermometer, a stirrer bar and a Liebig condenser, 73 parts of dimethyl naphthalate, 78 parts of dimethyl isophthalate, 112 parts of ethylene glycol, 20 parts of diethylene glycol and tetra as a catalyst 0.1 part of butyl titanate (TBT) was charged, and the transesterification reaction was allowed to proceed at 190 ° C to 230 ° C for 3 hours. Subsequently, 44 parts of orthophthalic anhydride was additionally added, and the temperature was raised to 250 ° C., followed by polymerization for 80 minutes under reduced pressure to obtain a polyester resin M. The composition, molecular weight, glass transition temperature, and acid value of the obtained polyester resin M are shown in Table 1.

  The above comparative synthesis examples -10 and -13 are examples in which a dibasic acid having a naphthalene skeleton is included in the acid component of the polyester resin but a diol compound having a bisphenol A skeleton is not included in the glycol component. Synthesis Example 11 is an example in which the glycol component of the polyester resin contains a diol compound having a bisphenol A skeleton, but the acid component does not have a dibasic acid compound having a naphthalene skeleton. Comparative Synthesis Example-12 is an example in which the acid component of the polyester resin does not contain a dibasic acid having a naphthalene skeleton, and the glycol component does not contain a diol compound having a bisphenol skeleton.

  The result of having evaluated the refractive index and coating film toughness of the polyester resin obtained by the said synthesis example and the comparative synthesis example below is shown.

  Polyester resins A, B, C, D, E, F, G, J, K, L, and M were dissolved in cyclohexanone to obtain a solution having a solid content concentration of 30 wt%.

  27 parts of n-butyl cellosolve is added to 100 parts of polyester resin H, and a uniform solution state is obtained at 150 ° C. While stirring, 243 parts of deionized water at 90 ° C. was gradually added to prepare an aqueous dispersion having a solid concentration of 27%. An aqueous dispersion of polyester resin I was prepared in the same manner.

The evaluation results of the polyester resins A to I are Examples 1 to 9, and the evaluation results of the polyester resins J to M are comparative examples 10 to 13.
The evaluation results of the refractive index and coating film toughness are shown in Table 2. As a result, it turns out that the polyester resin of this invention has a high refractive index and tough coating-film characteristic.

  The polyester resin of the present invention includes a dicarboxylic acid component having a naphthalene skeleton and a glycol component having a bisphenol A skeleton as a copolymer component, and thus has a refractive index of 1.60 or more and tough coating properties. Moreover, since it is excellent in general-purpose organic solvent solubility and can be dispersed in water, it is expected to be applied to optical coating agents and the like.

Claims (6)

  A copolymerized polyester resin comprising at least a dicarboxylic acid component having a naphthalene skeleton and a glycol component having a bisphenol A skeleton as a copolymerization component.   The copolymer polyester resin according to claim 1, wherein the dicarboxylic acid component having a naphthalene skeleton is copolymerized in an amount of 50 mol% or more in the total acid component, and the glycol component having a bisphenol A skeleton is copolymerized in an amount of 50 mol% or more in the total glycol component.   Furthermore, the copolyester resin of Claim 2 with which polyalkylene glycol of the number average molecular weight 1000-6000 is copolymerized.   The copolyester resin according to claim 3, wherein the polyalkylene glycol is copolymerized in the range of 0.5 to 5 mol% in all glycol components.   An aqueous dispersion of the copolyester resin according to any one of claims 1 to 3.   An organic solvent-dissolved product of the copolyester resin according to any one of claims 1 to 3.