JP7069926B2 - Polyester resin composition, ink binder and ink composition - Google Patents

Description

The present invention relates to a polyester resin composition, and is particularly suitable as a binder resin for printing ink for printing on plastic, glass, metal or the like as a printing object. More specifically, it is suitable for evaporation-drying ink that can be used in a wide range of printing styles.

The printing ink needs to be fixed after being transferred from the plate to the object to be printed. The method of fixing, that is, drying differs depending on the vehicle composition of the printing ink, but generally there are an evaporation drying type, an oxidation polymerization type, a two-component reaction type, an ultraviolet curing type, and a penetration drying type.

The composition of the printing ink consists of colorants such as pigments and dyes, vehicles such as resins and oils and solvents, and auxiliary agents such as dispersants, defoamers and plasticizers. Therefore, it is required that the binder resin for ink does not impair the color tone of the colorant, has good compatibility with the auxiliary agent, and does not bleed out.

For example, Patent Document 1 describes the use of an ester compound as a plasticizer having high compatibility with a polyester resin and difficult to bleed out.

Japanese Unexamined Patent Publication No. 2005-154681

However, the method described in Patent Document 1 still has insufficient compatibility and may bleed out.
An object of the present invention is to provide a binder polyester resin composition for ink, which does not impair the color tone of a colorant, has good compatibility with an auxiliary agent, and is difficult to bleed out.

The present invention has the following aspects.
[1] A polyester resin containing a polyester resin (A) having a number average molecular weight of 1500 or more and a glass transition temperature Tg of 50 ° C. or less, and a polyester resin (B) having a number average molecular weight of 1500 or more and a Tg of 55 ° C. or more. Composition.
[2] The polyester resin composition according to claim 1, wherein the polyester resin (A) contains 10 to 50 mol% of a constituent unit derived from an aliphatic dicarboxylic acid when the total acid component is 100 mol%.
[3] The polyester resin composition according to claim 1, wherein the polyester resin (B) contains 0.5 to 3 mol% of a constituent unit derived from a trihydric or higher alcohol when the total acid component is 100 mol%.
[4] The method according to [1], wherein the mixing ratio of the polyester resin (A) and the polyester resin (B) (polyester resin (A) / polyester resin (B)) is 20/80 to 80/20 (mass ratio). Polyester resin composition for ink.
[5] A binder for ink containing the polyester resin composition according to [1] to [4].
[6] An ink composition containing the binder for ink according to [5] and a solvent, a pigment or a dye.

By using the polyester resin composition for ink of the present invention, it is possible to provide a binder for ink that does not impair the color tone of the colorant, has good compatibility with an auxiliary agent, and is difficult to bleed out.

<Polyester resin composition>
The polyester resin composition of the present invention comprises a polyester resin (A) having a number average molecular weight of 1500 or more and a glass transition temperature Tg of 50 ° C. or less, and a polyester resin (B) having a number average molecular weight of 1500 or more and a Tg of 55 ° C. or more. ) And.

In the present invention, the polyester resin (A) having a low glass transition temperature Tg imparts adhesion to the substrate, and the polyester resin (B) having a high glass transition temperature imparts coating strength.
In this case, when the number average molecular weights of the polyester resin (A) and the polyester resin (B) are both 1500 or more, the compatibility between the polyester resins is improved and the color contributes to the color tone of the auxiliary agent or the ink. It is possible to stabilize the dispersion state of the charges and prevent bleed-out.

The number average molecular weight of the polyester resin (A) and the polyester resin (B) is preferably 1800 or more, and more preferably 2000 or more, from the viewpoint of the coating strength of the ink. The number average molecular weight can be obtained by converting the retention time corresponding to the peak value of the obtained elution curve into standard polystyrene by the GPC method.

The glass transition temperature Tg of the polyester resin (A) is preferably 50 ° C. or lower in terms of improving the adhesion to the substrate. In terms of ease of pelletizing the resin, −15 ° C. or higher is preferable, and 0 ° C. or higher is more preferable. The glass transition temperature Tg of the polyester resin (B) is preferably 55 ° C. or higher in terms of improving the strength of the coating film. From the viewpoint of ease of pulverization, 80 ° C. or lower is preferable, and 70 ° C. or lower is more preferable. The glass transition temperature Tg can be obtained from the endothermic curve measured by using a differential scanning calorimeter.

It is preferable that the polyester resin (A) contains 10 to 50 mol% of the constituent unit derived from the aliphatic dicarboxylic acid when the constituent unit derived from the polyvalent carboxylic acid is 100 mol%. The Tg of the resin can be reduced by containing 10 mol% or more of the constituent units derived from the aliphatic dicarboxylic acid. When the constituent unit derived from the aliphatic dicarboxylic acid is contained in an amount of more than 50 mol%, the Tg of the resin tends to be less than -15 ° C.

Further, in the present invention, the polyester resin (A) contains 0.5 to 3 mol% of a trihydric or higher alcohol-derived constituent unit when the constituent unit derived from the polyvalent carboxylic acid is 100 mol%. Is preferable. If the constituent unit derived from an alcohol having a trivalent or higher content is less than 0.5 mol%, the reactivity tends to be slow, and if it exceeds 3 mol%, the gel content cannot be suppressed and the solvent solubility of the resin tends to be insufficient. From the viewpoint of reactivity, 1.5 mol% or more is preferable, and from the viewpoint of gel content suppression and solvent solubility, 3 mol% or less is preferable.

Further, the gel content of the polyester resin (A) is preferably 10% or less. If the gel content is more than 10%, the solvent solubility of the resin becomes insufficient, and the smoothness of the ink and the adhesion to the substrate are lowered.

The polyester resin (A) of the present invention contains a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyhydric alcohol by polycondensing the polyvalent carboxylic acid and the polyhydric alcohol.

Examples of the polyvalent carboxylic acid include the following. Divalent carboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, dibutyl isophthalate, or esters or acid anhydrides thereof, azeline. Acid, sebasic acid, isodecylsuccinic acid, dodecenylsuccinic acid, maleic acid, fumaric acid, adipic acid, succinic acid, oxalic acid, glutaric acid, pimelic acid, suberic acid, dodecazionic acid, 1,4-cyclohexanedicarboxylic acid, 1, 3-Cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid or an aliphatic dicarboxylic acid such as an ester or acid anhydride thereof. Trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalentricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1, 2,7,8-octanetetracarboxylic acid, or an ester or acid anhydride thereof. These can be used in combination of two or more.

As the aliphatic dicarboxylic acid, succinic acid, fumaric acid, adipic acid, azelaic acid, and sebacic acid are preferable because they are easily available industrially, and adipic acid and sebacic acid are more preferable because they are easy to handle.

In addition, examples of the polyhydric alcohol include the following. Examples of the aliphatic diol include ethylene glycol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, and 1,4. -Cyclohexanedimethanol, isosorbide, erythritan and the like can be mentioned. The aromatic diols include bisphenol A, polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, and polyoxypropylene- (2.0) -2,2-bis (4). -Hydroxyphenyl) propane, polyoxypropylene- (2.2) -polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.3) -2 , 2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -2,2-bis (4-) Hydroxyphenyl) propane, polyoxypropylene- (2.4) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (3.3) -2,2-bis (4-hydroxyphenyl) propane Alcohols such as bisphenol A alkylene oxide adduct such as bisphenol A alkylene oxide adduct can be mentioned. These can be used alone or in combination of two or more, and can also be used in combination with an aliphatic diol and an aromatic diol.

Among these, ethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, isosorbide, and polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane are from the viewpoint of polymerization reactivity. Ethylene glycol, neopentyl glycol, polyoxypropylene- (2.3) -2,2-bis (4-hydroxyphenyl) propane, 1,4-cyclohexanedimethanol are preferable from the viewpoint of availability. Neopentyl glycol is most preferable from the viewpoint of reducing colorability.

The polyester resin (A) may contain a structural unit derived from a trihydric or higher alcohol other than the above. Examples of the trihydric or higher alcohol other than the above include the following. Sorbitol, 1,2,3,6-hexatetralol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentatriol, glycerin , 2-Methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like. These alcohol components may be used alone or in combination of two or more.
Among these, glycerin and trimethylolpropane are preferable as the trihydric or higher alcohol component because they are industrially easily available.

The polyester resin (A) is obtained by polycondensing a polyvalent carboxylic acid and a polyhydric alcohol.

Further, in the present invention, the polyester resin (B) contains 0.5 to 3 mol% of a trihydric or higher alcohol-derived constituent unit when the constituent unit derived from the polyvalent carboxylic acid is 100 mol%. Is preferable. If the constituent unit derived from an alcohol having a trivalent or higher content is less than 0.5 mol%, the reactivity tends to be slow, and if it exceeds 3 mol%, the gel content cannot be suppressed and the solvent solubility of the resin tends to be insufficient. From the viewpoint of reactivity, 1.5 mol% or more is preferable, and from the viewpoint of gel content suppression and solvent solubility, 3 mol% or less is preferable.

The gel content of the polyester resin (B) is preferably 10% or less. If the gel content is more than 10%, the solvent solubility of the resin becomes insufficient, and the smoothness of the ink and the adhesion to the substrate are lowered.

Similar to the polyester resin (A), the polyester resin (B) of the present invention is also derived from a constituent unit derived from a polyvalent carboxylic acid and a polyhydric alcohol by polycondensing the polyvalent carboxylic acid and the polyhydric alcohol. Includes building blocks.

Examples of the polyvalent carboxylic acid include the following. Divalent carboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, dibutyl isophthalate, or esters or acid anhydrides thereof, azeline. Acid, sebasic acid, isodecylsuccinic acid, dodecenylsuccinic acid, maleic acid, fumaric acid, adipic acid, succinic acid, oxalic acid, glutaric acid, pimelic acid, suberic acid, dodecazionic acid, 1,4-cyclohexanedicarboxylic acid, 1, 3-Cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid or an aliphatic dicarboxylic acid such as an ester or acid anhydride thereof. Trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalentricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1, 2,7,8-octanetetracarboxylic acid, or an ester or acid anhydride thereof. These can be used in combination of two or more.

In addition, examples of the polyhydric alcohol include the following. Examples of the aliphatic diol include ethylene glycol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, and 1,4. -Cyclohexanedimethanol, isosorbide, erythritan and the like can be mentioned. The aromatic diols include bisphenol A, polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, and polyoxypropylene- (2.0) -2,2-bis (4). -Hydroxyphenyl) propane, polyoxypropylene- (2.2) -polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.3) -2 , 2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -2,2-bis (4-) Hydroxyphenyl) propane, polyoxypropylene- (2.4) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (3.3) -2,2-bis (4-hydroxyphenyl) propane Alcohols such as bisphenol A alkylene oxide adduct such as bisphenol A alkylene oxide adduct can be mentioned. These can be used alone or in combination of two or more, and can also be used in combination with an aliphatic diol and an aromatic diol.

Among these, ethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, isosorbide, and polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane are from the viewpoint of polymerization reactivity. Ethylene glycol, neopentyl glycol, polyoxypropylene- (2.3) -2,2-bis (4-hydroxyphenyl) propane, 1,4-cyclohexanedimethanol are preferable from the viewpoint of availability. Neopentyl glycol is most preferable from the viewpoint of reducing colorability.

The polyester resin (B) may contain a structural unit derived from a trihydric or higher alcohol other than the above. Examples of the trihydric or higher alcohol other than the above include the following. Sorbitol, 1,2,3,6-hexatetralol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentatriol, glycerin , 2-Methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like. These alcohol components may be used alone or in combination of two or more. Among these, glycerin and trimethylolpropane are preferable as the trihydric or higher alcohol component because they are industrially easily available.

Further, in the present invention, the mixing ratio of the polyester resin (A) and the polyester resin (B) (polyester resin (A) / polyester resin (B)) is 20/80 to 80/20 from the viewpoint of the coating strength of the ink. (Mass ratio) is preferable, and 50/50 to 80/20 (mass ratio) is more preferable.

<Manufacturing method of polyester resin (A) and (B)>
In the methods for producing the polyester resins (A) and (B), the polymerization catalysts include, for example, titanium tetraalkoxide, tetrabutoxytitanium, titanium oxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, and dioxide. A polymerization catalyst such as germanium or magnesium acetate can be used. The titanium catalyst needs to be polymerized using 30 ppm to 1000 ppm with respect to the total acid components used in the raw materials. If the titanium catalyst is less than 30 ppm or more than 1000 ppm, the polymerization reactivity is lowered and a resin having a predetermined softening temperature cannot be obtained in a short time. Further, the inorganic catalyst needs to be polymerized using 1000 ppm to 3000 ppm with respect to the total acid component used as the raw material. If the amount of the inorganic catalyst is less than 1000 ppm or more than 3000 ppm, the polymerization reactivity is lowered and a resin having a predetermined softening temperature cannot be obtained in a short time.

As a method of the polymerization reaction in the polyester resins (A) and (B), a polyvalent carboxylic acid and a polyhydric alcohol are put into a reaction vessel, and water or a lower alkyl alcohol is distilled by an esterification reaction or an ester exchange reaction. After that, there is a method of obtaining a resin by increasing the degree of polymerization while removing glycol by a condensation reaction.

The temperature of the esterification reaction or transesterification reaction of the polyester resins (A) and (B) is preferably 220 ° C to 280 ° C. This is because the productivity is improved by setting the temperature to 220 ° C or higher, and 245 ° C or higher is more preferable. Further, when the temperature is 280 ° C. or lower, the decomposition of the resin and the by-production of volatile components that cause an odor tend to be suppressed, and the temperature is more preferably 270 ° C. or lower. The temperature of the condensation reaction is preferably 220 ° C to 280 ° C. This is because when the temperature of the condensation reaction is 220 ° C. or higher, the productivity tends to be good, and when the temperature is 270 ° C. or lower, the decomposition of the resin can be suppressed and the productivity is good, or a factor of odor. This is because there is a tendency to suppress the by-production of volatile components. It is preferable to set the condensation reaction temperature in the above temperature range in consideration of the raw material composition ratio and the like. During the condensation reaction, the pressure inside the reaction vessel is preferably reduced to 0.5 kPa · abs. When it is 0.5 kPa · abs or less, the reactivity tends to be good and the productivity is improved.

<Ink binder>
The ink binder of the present invention dissolves the polyester resin composition for ink of the present invention in a solvent to prepare a resin solution. As the solvent, any solvent that can dilute the polyester resin composition of the present invention can be used without any limitation.

For example, aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane, octane and decane, esters such as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate, ethyl formate and butyl propionate. System, alcohol system such as methanol, ethanol, propanol, butanol, 2-ethylhexanol, ethylene glycol, ketone system such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, ether system such as dioxane, diethyl ether, tetrahydrofuran, cellosolve. Examples thereof include various cellosolve-based solvents such as acetate, ethyl cellosolve, butyl cellosolve, and butyl carbitol.

The polyester resin composition for ink is diluted with the above-mentioned solvent to adjust the concentration. If the concentration is high, the viscosity is high and coating becomes difficult. On the other hand, if the concentration is low, the film thickness at the time of coating becomes too thin. Therefore, the concentration is usually adjusted to about 20 to 70% by mass, preferably 30 to 60% by mass. ..

<Ink composition>
In the ink composition of the present invention, an inorganic colorant and an organic colorant can be used as the colorant. Examples of the inorganic colorant include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, aluminum hydroxide, chromium oxide, silica, carbon black, aluminum, and mica. Organic colorants include organic pigments and dyes, for example, azo-based, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindoline-based, quinophthalone-based, and azomethine-azo-based. , Diketopyrrolopyrrole type, isoindoline type and the like.

The colorant is preferably contained in an amount sufficient to secure the concentration and colorability of the printing ink, that is, in a ratio of 1 to 50% by mass with respect to the total mass of the printing ink. In addition, these colorants can be used alone or in combination of two or more.

In order to stably disperse a colorant such as a pigment, the binder resin alone can be used, but a pigment dispersant can also be used in combination to stably disperse the pigment. As the pigment dispersant, a surfactant such as anionic, nonionic, cationic or zwitterionic can be used. From the viewpoint of ink stability, the pigment dispersant is preferably contained in a proportion of 0.05 to 10% by mass with respect to the total weight of the printing ink composition.

In addition, if necessary, additives such as fats and oils, leveling agents, defoaming agents, silane coupling agents, plasticizers, wetting agents, emulsifiers, viscosity modifiers and the like can be included.

Examples of the present invention are shown below, but the embodiment of the present invention is not limited thereto. Moreover, the evaluation method and the manufacturing method of the polyester resin (A) and (B) shown in this Example are as follows.

[Evaluation method of polyester resin (A) and (B)]
<Glass transition temperature Tg>
Using the differential scanning calorimeter DSC-60Aplus manufactured by Shimadzu Corporation, the temperature at the intersection of the baseline of the chart and the tangent of the heat absorption curve near the glass transition temperature when measured at a temperature rise rate of 5 ° C / min. I asked.

<Softening temperature>
When measured using a flow tester CFT-500D manufactured by Shimadzu Corporation with a 1 mmφ x 10 mm nozzle under a load of 294 N (30 kgf) and an isothermal temperature rise rate of 3 ° C./min. The temperature at which 1/2 of 1.0 g of the sample flowed out was determined.

<Acid value>
Approximately 0.2 g of the sample was precisely weighed in an Erlenmeyer flask with branches (A (g)), 20 mL of benzyl alcohol was added, and the resin was dissolved by heating in a heater at 230 ° C. under a nitrogen atmosphere for 15 minutes. After allowing to cool to room temperature, 20 mL of chloroform and several drops of cresol red solution as an indicator were added and titrated with a 0.02 specified potassium hydroxide (KOH) solution (drop quantification = B (mL), titer of KOH solution =). f). The blank measurement was performed in the same manner (titration = C (mL)), and the calculation was performed according to the following formula.
Acid value (mgKOH / g) = (BC) x 0.02 x 56.11 x f ÷ A

<Hydroxy group value>
About 5.0 g of the sample was precisely weighed in an Erlenmeyer flask (A (g)), 50 mL of THF was added, and the sample was completely dissolved. 30 mL of dimethylaminopyridine / THF solution was added, 10 mL of acetic anhydride / THF solution was added, and then the mixture was stirred for 15 minutes. Further, 3 mL of distilled water was added, and after stirring for 15 minutes, 50 mL of THF and 25 mL of 0.5N KOH solution were added. Several drops of phenolphthalein solution were added as an indicator, and titration was performed with 0.5 specified KOH solution (titration = B (mL), titer of KOH solution = f). The blank measurement was performed in the same manner (titration = C (mL)), and the calculation was performed according to the following formula.
Hydroxy group value (mgKOH / g) = (CB) × 56.11 × f ÷ A + acid value

<Gel fraction (THF insoluble matter)>
0.5 g of the resin was precisely weighed in a 100 mL Erlenmeyer flask (A (g)), 50 mL of THF was added, and the resin was dissolved in a water bath set at 70 ° C. for 3 hours. On the other hand, the glass filter 1GP100 was tightly filled with Celite 545 from 6 to 7 minutes, dried in a vacuum dryer at 105 ° C. for 3 hours or more, and weighed (B (g)). Subsequently, a THF solution in which the resin was dissolved was transferred into a dry glass filter and suction filtered. Use acetone to transfer all the contents remaining on the wall of the Erlenmeyer flask into a glass filter, pour acetone through the glass filter, drop the solubles into a suction bottle, and continue suction so that no solvent remains in the filter. After that, it was dried in a vacuum dryer at 80 ° C. for 1 hour or more, weighed (C (g)), and calculated according to the following formula.
Gel fraction (% by mass) = (CB) / A × 100

<Molecular Weight: Mass Average Molecular Weight (Mw), Peak Molecular Weight (Mp), Number Average Molecular Weight (Mn), Dispersity (Mw / Mn)>
By the GPC method, the mass average molecular weight (Mw), peak molecular weight (Mp), number average molecular weight (Mn), and dispersity (Mw / Mn) are converted into standard polystyrene from the retention time corresponding to the peak value of the elution curve obtained. Asked by. The peak value of the elution curve is a point where the elution curve shows a maximum value, and when the maximum value is two or more points, the elution curve gives a maximum value.
Equipment: HLC8020 manufactured by Toyo Soda Industries Co., Ltd.
Column: Three TSKgelGMHXL (column size: 7.8 mm (ID) x 30.0 cm (L)) manufactured by Toyo Soda Industries Co., Ltd. are connected in series. Oven temperature: 40 ° C.
Eluent: THF
Sample concentration: 4 mg / 10 mL
Filtration conditions: 0.45 μm Teflon® membrane filter to filter the sample solution Flow rate: 1 mL / min Injection volume: 0.1 mL
Detector: RI
Standard polystyrene sample for preparing calibration lines: TSK standard, manufactured by Toyo Soda Kogyo Co., Ltd., A-500 (molecular weight 5.0 × 10 ² ), A-2500 (molecular weight 2.74 × 10 ³ ), F-2 (molecular weight 1) .96 x ^{10 4} ), F-20 (molecular weight 1.9 x 105), F-40 (molecular weight 3.55 x 105), F ^- 80 (molecular weight 7.06 x 105), F ^- 128 (molecular weight 7.06 x 105) Molecular weight 1.09 × 10 ⁶ ), F-288 (molecular weight 2.89 × 10 ⁶ ), F-700 (molecular weight 6.77 × 10 ⁶ ), F-2000 (molecular weight 2.0 × 10 ⁷ ).

[Manufacturing method of polyester resin (A) and (B)]
The polyvalent carboxylic acid, polyhydric alcohol, and catalyst having the charged compositions shown in Tables 1 and 2 were charged into a reaction vessel equipped with a distillation column. Then, the temperature was started to rise, and the temperature in the reaction system was heated to 265 ° C., and this temperature was maintained, and the esterification reaction was carried out until water did not distill out from the reaction system. Next, while maintaining the temperature inside the reaction system at 265 ° C., the inside of the reaction vessel was depressurized to 0.5 kPa · abs and stirred at 200 rpm to carry out a condensation reaction while distilling the polyhydric alcohol from the reaction system. At the end point of polymerization, when the condensation reaction time shown in Tables 1 and 2 has elapsed, stirring of the reactor is stopped, the inside of the apparatus is set to normal pressure, the inside of the apparatus is pressurized with nitrogen, and the reactants are taken out from the lower part of the apparatus and taken out at 100 ° C. The following was cooled to obtain a polyester resin (A) and a polyester resin (B). The characteristic values of the obtained resin are shown in Tables 3 and 4.
In the polyester resin (A) -e in Table 1, the hydroxyl value and colorability shown in Table 3 could not be measured by the method described in the present specification. Further, the polyester resin (B) having a Tg of 55 ° C. or higher and a Mn of 1500 or lower could not be manufactured by this manufacturing method.

TPA：テレフタル酸
IPA：イソフタル酸
ADA：アジピン酸
SbA：セバシン酸
TMA：トリメリット酸
EG：エチレングリコール
NPG：ネオペンチルグリコール
TMP：トリメチロールプロパン
BPP：ポリオキシプロピレン－（２．３）－２，２－ビス（４－ヒドロキシフェニル）プロパン
BPE：ポリオキシエチレン－（２．０）－２，２－ビス（４－ヒドロキシフェニル）
Sb₂O₃：三酸化アンチモン
TBT：テトラブトキシチタン

TPA: terephthalic acid
IPA: Isophthalic acid
ADA: Adipic acid
SbA: Sebacic acid
TMA: Trimellitic acid
EG: Ethylene glycol
NPG: Neopentyl glycol
TMP: Trimethylolpropane
BPP: Polyoxypropylene- (2.3) -2,2-bis (4-hydroxyphenyl) propane
BPE: Polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl)
Sb ₂ O ₃ : Antimony trioxide
TBT: Tetrabutoxytitanium

(Examples 1 to 6, Comparative Examples 1 to 3)
According to the resin type and resin mixing ratio and the solvent type and the resin / solvent ratio shown in Table 5, the mixture was allowed to stand in methyl ethyl ketone for 7 days or more to dissolve it in a glass container.

<Solubility>
13 mL of the dissolved resin solution was put into a glass container AX-SV-35, and the viscosity was measured at 25 ° C. at a natural frequency of 30 Hz using a sound fork type vibration viscometer SV-10A manufactured by A & D Co., Ltd. gone. From the obtained viscosity (η: mPa ・ s ・ g / cm ³ ), the following evaluation criteria were set for the binder resin for ink.
○ (Good): η is 20 mPa ・ s ・ g / cm ³ or more and 1000 mPa ・ s ・ g / cm ³ or less × (Inferior): η is 20 mPa ・ s ・ g / cm ³ or less or 1000 mPa ・ s ・ g / cm ³ or more or resin
If does not dissolve.

<Coloring>
Approx. The measurement was performed by selecting the method, the field of view: 2 °, and the main light source: C. The obtained b value was calculated based on the resin mixing ratio in Table 5 according to the following formula, and the calculated value was rounded off to the second decimal place.
Mixing b value of polyester resin (A) and polyester resin (B) = b value of polyester resin (A) x mixing ratio + b value of polyester resin (B) x mixing ratio Resin mixing using the b value of this resin alone It was found that b showed a good correlation with the evaluation of "yellowness" when the resin solution was visually observed, and the following evaluation criteria were set for the determination.
〇 (Good): The mixed b value of the polyester resin (A) and the polyester resin (B) is 2.5 or less Δ (Available): The mixed b value of the polyester resin (A) and the polyester resin (B) is 2.6. 5.0 or less × (inferior): The mixed b value of the polyester resin (A) and the polyester resin (B) is 5.1 or more.

In Comparative Example 1, when d having a Tg of 50 ° C. or higher was used for the polyester resin (A), the viscosity was gelled and could not be measured, and the coloring property was also low.
In Comparative Example 2, when e having a number average molecular weight (Mn) of less than 1500 was used for the polyester resin (A), the viscosity was low and the colorability could not be measured by the method described in the present specification.
In Comparative Example 3, when h having a Tg of less than 55 ° C. was used for the polyester (B), the solubility was poor, the viscosity could not be measured, and the coloring property was also low.

The polyester resin composition of the present invention can be used for various printing inks, clear inks and the like.

Claims (6)

A polyester resin (A) having an acid value of 1.2 mgKOH / g or less, a number average molecular weight of 1500 to 3300, and a glass transition temperature Tg of 50 ° C. or less.
It contains a polyester resin (B) having an acid value of 0.9 mgKOH / g or less, a number average molecular weight of 1500 to 3800, and a Tg of 55 ° C. or higher.
A polyester resin composition in which the mixing ratio of the polyester resin (A) and the polyester resin (B) (polyester resin (A) / polyester resin (B)) is 20/80 to 80/20 (mass ratio) . The polyester resin composition according to claim 1, wherein the polyester resin (A) contains 10 to 50 mol% of a constituent unit derived from an aliphatic dicarboxylic acid when the constituent unit derived from a polyvalent carboxylic acid is 100 mol%. .. Claim 1 or claim that the polyester resin (B) contains 0.5 to 3 mol% of a constituent unit derived from a trihydric or higher alcohol when the constituent unit derived from a polyvalent carboxylic acid is 100 mol%. 2. The polyester resin composition according to 2. The polyester resin composition according to any one of claims 1 to 3, wherein the polyester resin (A) has a gel fraction of 10% or less, and the polyester resin (B) has a gel fraction of 10% or less. .. A binder for ink containing the polyester resin composition according to any one of claims 1 to 4. An ink composition containing the binder for ink according to claim 5 and a solvent, a pigment or a dye.