JP2007211089A - Soluble copolyester resin having good light resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copolyester resin having good light resistance and excellent dissolution property. <P>SOLUTION: The soluble copolyester resin contains isophthalic acid component as 30-100 mol.% of the total carboxylic acid component and alicyclic glycol component as 20-50 mol.% of the total glycol component and is soluble at a concentration of ≥10 mass.% in a 2-butanone/toluene mixed solvent (1/1 mass ratio) at 25°C. The invention further provides a polyester solution containing the soluble copolyester resin in an amount of 10-50 mass.% and produced by using a solvent comprising one or more compounds selected from cyclohexanone, 2-butanone and toluene. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a copolyester resin having good light resistance and excellent dissolution performance.

  Polyester resins have excellent chemical and physical properties and are widely used as coating solutions by dissolving them in general-purpose solvents from the viewpoint of excellent workability. However, there is a problem that the obtained painted surface is easily discolored by light. This discoloration is usually yellowish and is therefore called “yellowing”.

  As a polyester in which yellowing is suppressed, Patent Document 1 discloses that terephthalic acid is a main acid component, 20 to 80 mol% of 1,4-cyclohexanedimethanol is copolymerized as a diol component, and a naphthalene skeleton is added in an amount of 0.0. Polyester resins having 5 to 5 mol% are disclosed. Patent Document 2 proposes a copolyester consisting only of isophthalic acid and neopentyl glycol.

JP 2003-221435 A Japanese Patent Laid-Open No. 06-234941

  However, the polyester described in Patent Document 1 is premised on the use as a molded article, and the polyester described in Patent Document 2 is used as a powder coating, both of which are soluble in general-purpose solvents. It was not a material that can be used for purposes such as coating.

  An object of the present invention is to solve the above problems and to provide a polyester resin having excellent light resistance and good solubility in a general-purpose solvent.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by copolymerizing a specific monomer component at a specific ratio, and have reached the present invention.

That is, the gist of the present invention is as follows.
[1] Copolyester having 30 to 100 mol% of all carboxylic acid components as an isophthalic acid component and 20 to 50 mol% of all glycol components as an alicyclic glycol component. A soluble copolyester resin which is dissolved in a toluene mixed solvent (mass ratio 1/1) at a concentration of 10% by mass or more.
[2] A polyester solution containing the soluble copolyester resin according to [1] in a range of 10 to 50% by mass and using one or more selected from the group consisting of cyclohexanone, 2-butanone and toluene as a solvent.
[3] A paint or coating agent using the polyester solution according to [2].

  ADVANTAGE OF THE INVENTION According to this invention, the polyester resin which is soluble in a general purpose solvent, is hard to yellow, and was excellent in light resistance performance and melt | dissolution performance is provided, and is used favorably as a coating material or a coating agent. Therefore, industrial utility value is extremely high.

  Hereinafter, the present invention will be described in detail.

  As a carboxylic acid component of the polyester resin, it is necessary to copolymerize isophthalic acid in an amount of 30 to 100 mol%, and more preferably 50 to 100 mol%. When the amount of isophthalic acid is less than 30 mol%, both the light resistance and dissolution performance tend to deteriorate, which is not preferable.

  Other carboxylic acid components include terephthalic acid, phthalic anhydride, naphthalenedicarboxylic acid, aromatic dicarboxylic acids such as 4,4'-dicarboxybiphenyl, 5-sodium sulfoisophthalic acid, oxalic acid, malonic acid, succinic acid, Saturated aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, octadecanedioic acid, aicosanedioic acid, fumaric acid, maleic anhydride, itaconic acid, mesaconic acid, citraconic acid, etc. Saturated aliphatic dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornenedicarboxylic acid, tetrahydrophthalic acid alicyclic dicarboxylic acid or ester formation Sex derivatives and the like.

  As a glycol component, it is necessary to copolymerize alicyclic glycol at 20-50 mol%, and it is more preferable to set it as 25-45 mol%. When it is less than 20 mol%, good light resistance cannot be obtained. Moreover, when it exceeds 50 mol%, melt | dissolution performance will worsen, and superposition | polymerization time will become long and productivity will fall. Examples of the alicyclic glycol include 1,2-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, 1,4-cyclohexane dimethanol, and the like, among others, 1,4-cyclohexane dimethanol having excellent cost performance. Is the best.

  Examples of glycol components other than alicyclic glycol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2 -Methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3-propanediol, 2-amino-2-ethyl-1 , 3-propanediol, 2-amino-2-methyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol Neopentyl glycol, 3-methyl-1,5-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-hept Diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 3 (4), 8 (9) -bis (hydroxymethyl) -tricyclo (5.2.1.1/2 .6) Ethylene oxide adducts of aliphatic glycols such as decane, diethylene glycol, triethylene glycol, dipropylene glycol and tripropylene glycol, bisphenol A, bisphenol S, bisphenol C, bisphenol Z, bisphenol AP and 4,4'-biphenol Alternatively, propylene oxide adducts, polyethylene glycol, polypropylene glycol and the like can be mentioned, and among them, versatile ethylene glycol, neopentyl glycol, 1,2-propanediol, and 1,4-butanediol are preferable. In particular, neopentyl glycol is preferably copolymerized at 80 mol% or less, more preferably 20 to 80 mol% in the glycol component, from the viewpoint of obtaining good light resistance.

  In the polyester of the present invention, a hydroxycarboxylic acid may be used depending on purposes such as appropriate flexibility, improved adhesion, and adjustment of the glass transition temperature. Such components include ethylene oxide adduct of p-hydroxybenzoic acid, ethylene oxide adduct of m-hydroxybenzoic acid, ethylene oxide adduct of o-hydroxybenzoic acid, lactic acid, oxirane, β-propiolactone, β-butyrolactone. , Γ-butyrolactone, δ-valerolactone, ε-caprolactone, glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxy Examples include valeric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 10-hydroxystearic acid, and the like.

  Moreover, if it is a small amount, you may use a trifunctional or more than trifunctional carboxylic acid component and alcohol component as a copolymerization component. At this time, the trifunctional or higher functional monomer is suitably about 0.2 to 5 mol% with respect to the total carboxylic acid component or total alcohol component. If the amount is less than 0.2 mol%, the added effect may not be achieved. If an amount exceeding 5 mol% is included, gelation may exceed the gel point during polymerization. Examples of the tri- or higher functional carboxylic acid component include aromatics such as trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, and trimesic acid. Aliphatic polyvalent carboxylic acids such as carboxylic acid and 1,2,3,4-butanetetracarboxylic acid. Examples of the tri- or higher functional alcohol component include glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, α-methylglucose, mannitol, and sorbitol.

  Moreover, monocarboxylic acid and monoalcohol may be copolymerized in the polyester resin in a small amount. Examples of monocarboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexane acid, 4-hydroxyphenyl stearic acid, and the like. Examples of the alcohol include octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and 2-phenoxyethanol.

  The polyester resin can be produced by combining the above-mentioned monomers and polycondensing by a known method. For example, all the monomers and / or low polymers thereof can be produced at 180 to 250 ° C., 2.5 under an inert atmosphere. For example, a method of carrying out an esterification reaction by reacting for about 10 hours and then proceeding a polycondensation reaction at a temperature of 220 to 280 ° C. under a reduced pressure of 130 Pa or less until a desired molecular weight is reached to obtain a polyester resin Can do.

  In the esterification reaction and polycondensation reaction, as required, germanium compounds such as germanium dioxide, organic titanate compounds such as tetrabutyl titanate, alkali metals such as zinc acetate and magnesium acetate, alkaline earths Polymerization is performed using an organic tin compound such as metal acetate, antimony trioxide, hydroxybutyltin oxide, or tin octylate. The amount of catalyst used at that time is usually 0.1% by mass or less based on the mass of the theoretically generated resin.

  When a desired acid value or hydroxyl value is imparted to the polyester resin, a carboxylic acid component or an alcohol component can be added following the polycondensation reaction, and depolymerization can be performed in an inert atmosphere.

  The copolymerized polyester resin of the present invention needs to be dissolved at a concentration of 10% by mass or more in a mixed solvent of 2-butanone / toluene (mass ratio 1/1) at 25 ° C. When it is not dissolved at a concentration of 10% by mass or more, workability when used as a paint or a coating agent is lowered. There is no particular upper limit on the dissolution concentration, but 50% by mass or less is preferable so that the viscosity of the solution does not become too high.

  Since the copolymerized polyester resin of the present invention is excellent in solubility in a solvent, it can be dissolved in various general-purpose solvents and used as a polyester solution. The solution concentration is preferably 10 to 50% by mass, and more preferably 10 to 30% by mass. Moreover, as a preferable solvent, at least 1 type which consists of cyclohexanone, 2-butanone, and toluene is mentioned. Of these, a mixed solvent of 2-butanone / toluene is generally preferable because of its high solubility, and most preferable is a mass ratio of 8/2 to 2/8.

  The difference between the color b value of the copolymerized polyester resin of the present invention before and after irradiation in a 1000 hour light fastness test according to ASTM D3424 (method 3) is preferably 3.0 or less.

  The number average molecular weight of the copolyester resin of the present invention is not particularly limited, but is preferably 2,000 to 30,000. When the number average molecular weight is less than 2,000, sufficient light resistance may not be obtained for the polyester material. When the number average molecular weight is 30,000 or more, the polymerization time may be very long.

  The glass transition temperature (hereinafter referred to as Tg) of the copolyester resin is not particularly limited, but is preferably 40 ° C to 120 ° C, and most preferably 40 ° C to 80 ° C when used as a solution in applications such as coating. .

  The copolymerized polyester resin of the present invention includes a curing agent, various additives, pigments such as titanium oxide, zinc white, and carbon black, dyes, other polyester resins, urethane resins, olefin resins, acrylic resins, alkyds as necessary. Resins, cellulose derivatives and the like can be blended.

  Moreover, additives such as a pigment dispersant, an ultraviolet absorber, a release agent, a pigment dispersant, and a lubricant can be blended with the copolymerized polyester resin of the present invention as necessary.

  The present invention will be specifically described below with reference to examples.

(1) Composition of copolymer polyester resin
^It calculated | required from < ¹ > H-NMR analysis (The product made by a Varian, 300MHz).

(2) Number average molecular weight of copolymerized polyester resin The number average molecular weight is determined by GPC analysis (liquid feeding unit LC-10ADvp type and UV-visible spectrophotometer SPD-6AV type manufactured by Shimadzu Corporation), detection wavelength: 254 nm, solvent : Chloroform, polystyrene conversion).

(3) Glass transition temperature of copolyester resin Using 10 mg of copolyester as a sample, measurement is performed using a DSC (Differential Scanning Calorimetry) apparatus (DSC7 manufactured by Perkin Elmer Co.) at a temperature increase rate of 10 ° C./min. Then, an intermediate value of two bending point temperatures derived from the glass transition in the obtained temperature rise curve was determined, and this was used as the glass transition temperature.

(4) Light resistance performance Using a copolyester resin, a plate of 300 × 500 mm and a thickness of 1.2 mm was prepared and used as a sample. Using a Xenon Arc Weather Ometer Ci4000 manufactured by ATLAS, according to ASTM D3424 method 3 (through window glass (printed material)), a xenon light continuous irradiation was performed to perform a 1000 hour light fastness test. Test conditions are as follows: wavelength 340 nm, black panel temperature 63 ± 3 ° C., humidity 40 ± 5%, irradiance 0.35 W / m ² , filters used: inner borosilicate, outer soda lime.

  The color b value of the plate before and after the light resistance acceleration test was measured using a color difference meter SZ-Σ90 manufactured by Nippon Denshoku Industries Co., Ltd., and the difference (after irradiation-before irradiation) was determined. If it is 3.0 or less, it is a range which does not have a problem practically, and was set as the pass.

(5) Dissolution performance In a glass container, 10 g of resin and 90 g of 2-butanone / toluene mixed solvent (mass ratio 1/1) (concentration: 10 mass%) are vibrated at 25 ° C. for 6 hours using a paint shaker. The dissolution state was observed. What was dissolved was "○", what was not dissolved was "X", and then left at 25 ° C for 1 day. If the dissolved state was maintained, "○", and phase separation occurred Was marked “x”. The same evaluation was performed on the resin 30 g and the mixed solvent 70 g (concentration 30% by mass).

  The same test was conducted using cyclohexanone as a solvent.

Example 1
830 g (50 mol parts) of terephthalic acid, 830 g (50 mol parts) of isophthalic acid, 372 g (60 mol parts) of ethylene glycol, 469 g (45 mol parts) of neopentyl glycol, 433 g (30 mol parts) of 1,4-cyclohexanedimethanol While stirring, the mixture consisting of was heated at 240 ° C. for 3 hours in an autoclave to carry out an esterification reaction. Next, the temperature was raised to 260 ° C., 0.4 g of zinc acetate and 0.5 g of antimony trioxide were added as catalysts, the pressure of the system was gradually reduced to 13 Pa after 1.5 hours, and a polycondensation reaction was performed. Polycondensation was performed until the viscosity reached an appropriate level, and the system was pressurized with nitrogen gas and discharged into pellets to obtain a copolyester.

  The number average molecular weight of this polyester is 16000, the glass transition point is 67 ° C., the difference in color b value (light resistance) before and after irradiation with xenon light is 2.0, the solid content concentration is 10% by mass and 30% by mass. The concentration of 2-butanone / toluene in a mixed solvent (mass ratio 1/1) and cyclohexanone was good, and the dissolved state was maintained after standing for 1 day. The resin composition and characteristics are shown in Table 1.

Polyester 2-6, Comparative Examples 1-3
The monomer used and the charged molar ratio were changed, and the same operation as in Example 1 was performed to obtain a copolyester. Table 1 shows the resin composition and characteristics of the obtained polyester.

   In Examples 1 to 6, resins having good light resistance and dissolution performance were obtained.

  On the other hand, each comparative example has the following problems.

  In Comparative Example 1, since the copolymerization ratio of isophthalic acid was low, both light resistance and dissolution performance were inferior.

  In Comparative Example 2, since the copolymerization ratio of 1,4-cyclohexanedimethanol was high, the dissolution performance was inferior.

In Comparative Examples 3 and 4, the copolymerization ratio of 1,4-cyclohexanedimethanol was low or not copolymerized at all, and thus the light resistance was inferior.

Claims (5)

A copolymerized polyester having 30 to 100 mol% of all carboxylic acid components as isophthalic acid components and 20 to 50 mol% of all glycol components as alicyclic glycol components, and a 2-butanone / toluene mixed solvent at 25 ° C A soluble copolyester resin which is dissolved in (mass ratio 1/1) at a concentration of 10% by mass or more. The soluble copolyester resin according to claim 1, wherein the alicyclic glycol is 1,4-cyclohexanedimethanol. The soluble copolyester resin according to claim 1, wherein a difference in color b value between before and after the test when a light resistance acceleration test for 1000 hours is conducted according to ASTM D3424 (method 3) is 3.0 or less. A polyester solution containing the soluble copolyester resin according to any one of claims 1 to 3 in a range of 10 to 50% by mass and using one or more selected from the group consisting of cyclohexanone, 2-butanone and toluene as a solvent. . A paint or coating agent using the polyester solution according to claim 4.