JP2017141348A - Polyester resin and method for producing polyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester that has excellent transparency when dissolved in solvent and also has excellent resin crushability, the use of which makes it possible to reduce a gel content for increased transparency and also improve resin crushability at the time of production.SOLUTION: A polyester resin has, based on a constitutional unit derived from an acid of 100 mole, a constitutional unit derived from a trivalent or more alcohol of 0.5 mole or more and 3 mole or less, with a gel content of the resin being 10% or less.SELECTED DRAWING: None

Description

  The present invention relates to a polyester resin excellent in transparency and resin grindability when dissolved in a solvent.

Polyester resins are widely used in applications such as toners, coating materials, adhesives, and films. This polyester resin needs to be excellent in transparency when dissolved in a general-purpose solvent, and also needs to be pulverizable from the viewpoint of resin production.
Patent Documents 1 and 2 describe a copolyester resin that is soluble in a general-purpose solvent in which the content of a trivalent or higher alcohol and the number average molecular weight are defined.

JP-A-8-337646 JP-A-9-59587

However, the polyester resins described in Patent Documents 1 and 2 have a large gel content and are not sufficiently transparent when dissolved in a general-purpose solvent. Moreover, resin grindability was not sufficient.
An object of this invention is to provide the polyester excellent in transparency at the time of solvent melt | dissolution and resin grindability.

  The gist of the present invention is a polyester resin containing 0.5 mol to 3 mol of a trivalent or higher alcohol-derived structural unit with respect to 100 mol of the acid-derived structural unit, and having a resin gel content of 10% or less. is there.

  By using the polyester resin of the present invention, transparency during solvent dissolution is improved by suppressing the gel content. Further, by using the polyester resin of the present invention, the resin grindability at the time of production becomes easy due to the excellent resin grindability.

<Polyester resin>
The polyester resin of the present invention contains 0.5 mol to 3 mol of a trivalent or higher alcohol-derived structural unit with respect to 100 mol of the acid-derived structural unit, and the resin gel content is 10% or less.
By including the trivalent or higher alcohol-derived structural unit in an amount of 0.5 mol or more and 3 mol or less with respect to 100 mol of the acid-derived structural unit, transparency and grindability are improved.
If the trivalent or higher alcohol-derived structural unit is 0.5 mole or more per 100 moles of the acid-derived structural unit, the grindability will be good. Moreover, if a structural unit derived from a trivalent or higher alcohol is 3 mol% or less with respect to 100 moles of a structural unit derived from an acid, the gel content can be suppressed and the transparency is excellent. The amount of the trivalent or higher alcohol-derived structural unit is preferably 1.5 moles or more with respect to 100 moles of the structural unit derived from the acid from the viewpoint of grindability, and the structure derived from the acid from the viewpoint of gel content suppression and transparency. 3 mol or less is preferable with respect to 100 mol of unit, and 2.9 mol or less is more preferable.

<Trivalent or higher alcohol component>
Examples of the trihydric or higher alcohol component of the present invention include 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 Can be mentioned. These alcohol components may be used alone or in combination of two or more.

<Other alcohol components>
The polyester resin of the present invention may further contain a structural unit derived from a polyhydric alcohol other than those described above. Examples of polyhydric alcohols other than the above include ethylene glycol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, and triethylene. Diols such as glycol and polyethylene glycol, bisphenol A, polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -polyoxyethylene- (2.0) -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 And alcohols such as bisphenol A alkylene oxide adducts such as 2-bis (4-hydroxyphenyl) propane. In addition, these structural units may contain 2 or more types. From the viewpoint of reactivity, aliphatic diols are preferred.

<Constitutional unit derived from acid (acid component)>
In the present invention, examples of the acid-derived structural unit include the following.
Divalent carboxylic acids such as terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, dibutyl isophthalate, etc., or esters or acid anhydrides thereof, phthalic acid, sebacin Acids, isodecyl succinic acid, dodecenyl succinic acid, maleic acid, fumaric acid, adipic acid, succinic acid, or aliphatic dicarboxylic acids such as esters or acid anhydrides thereof. Trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1, 2,7,8-octanetetracarboxylic acid, or an ester or acid anhydride thereof. Trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1, 2,7,8-octanetetracarboxylic acid and acid anhydrides thereof. These can be used in combination of two or more.

<Gel content>
The gel content of the polyester resin of the present invention is 10% or less. When the gel content is 10% or less, transparency at the time of solvent dissolution is improved.
The gel content was determined from the following conditions.
Resin (Ag) was dissolved in tetrahydrofuran (THF) at 70 ° C. for 3 hours, filtered through a glass filter (Bg) filled with celite and dried, and the glass filter was dried again and weighed (Cg) It was calculated using the following formula.
THF-insoluble content (mass%) (gel content) = {(CB) / A} × 100%

<Peak top molecular weight>
It is preferable that the peak top molecular weight (Mp) by the gel permeation chromatography (GPC) of the polyester resin obtained by this invention is 30000 or less. When the peak top molecular weight (Mp) is 30000 or less, the grindability tends to be good.
In addition, the measurement of Mp was calculated | required by standard polystyrene conversion on the following conditions.
Apparatus: Toyo Soda Industry Co., Ltd., HLC8020
Column: Toyo Soda Industry Co., Ltd., TSKgelGMHXL (column size: 7.8 mm (ID) x 30.0 cm (L)) connected in series Oven temperature: 40 ° C
Eluent: THF
Sample concentration: 4 mg / 10 mL
Filtration conditions: Filter sample solution with 0.45 μm Teflon membrane filter Flow rate: 1 mL / min Injection amount: 0.1 mL
Detector: RI
Standard polystyrene samples for preparing calibration curves: TSK standard, A-500 (molecular weight 5.0 × 10 ² ), A-2500 (molecular weight 2.74 × 10 ³ ), F-2 (molecular weight 1) manufactured by Toyo Soda Industry Co., Ltd. .96 × 10 ⁴ ), F-20 (molecular weight 1.9 × 10 ⁵ ), F-40 (molecular weight 3.55 × 10 ⁵ ), F-80 (molecular weight 7.06 × 10 ⁵ ), F-128 ( 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 ).

<Method for producing polyester resin>
The polyester resin of the present invention can be produced by polycondensation of a polyhydric alcohol component containing 0.5 to 3 mol of a trivalent or higher alcohol component with respect to 100 mol of the acid component, and a polyvalent carboxylic acid component.
Examples of the trihydric or higher alcohol component include 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.
If the amount of the trivalent or higher alcohol component is 0.5 mol or more with respect to 100 mol of the acid component, the grindability is excellent, and if it is 3 mol% or less, the gel content can be suppressed and the transparency is improved. 1.5 mol or more is preferable with respect to 100 mol of the acid component from the viewpoint of grindability, 3 mol or less is preferable with respect to 100 mol of the acid component from the viewpoint of gel content suppression and transparency, and 2.9 mol or less is more preferable. .

  The polyhydric alcohol component may further contain a polyhydric alcohol other than the above. Examples of polyhydric alcohols other than the above include ethylene glycol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, and triethylene. Diols such as glycol and polyethylene glycol, bisphenol A, polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -polyoxyethylene- (2.0) -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 And alcohols such as bisphenol A alkylene oxide adducts such as 2-bis (4-hydroxyphenyl) propane. These can be used in combination of two or more.

In the present invention, examples of the polyvalent carboxylic acid contained in the polyvalent carboxylic acid component include the following.
Divalent carboxylic acids such as terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, dibutyl isophthalate, etc., or esters or acid anhydrides thereof, phthalic acid, sebacin Acids, isodecyl succinic acid, dodecenyl succinic acid, maleic acid, fumaric acid, adipic acid, succinic acid, or aliphatic dicarboxylic acids such as esters or acid anhydrides thereof. Trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1, 2,7,8-octanetetracarboxylic acid, or an ester or acid anhydride thereof. Trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1, 2,7,8-octanetetracarboxylic acid and acid anhydrides thereof. These can be used in combination of two or more.

The polycondensation method is not particularly limited. For example, the polycarboxylic acid component and the polyhydric alcohol component described above are put into a reaction vessel and polymerized through an esterification reaction or a transesterification reaction, and a polycondensation reaction. The method of doing is mentioned.
In the polymerization of the polyester resin, for example, a polymerization catalyst such as titanium tetraalkoxide, tetrabutoxytitanium, titanium oxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium dioxide, magnesium acetate or the like may be used. it can.
The temperature of the polycondensation is not particularly limited, but is preferably in the range of 180 ° C to 280 ° C. When the polycondensation temperature is 180 ° C. or higher, the productivity tends to be good, and when it is 280 ° C. or lower, the decomposition of the resin and the volatile by-product that causes odor tend to be suppressed. . The lower limit of the polycondensation temperature is more preferably 200 ° C. or higher, and particularly preferably 220 ° C. or higher. The upper limit of the polycondensation temperature is more preferably 270 ° C. or less.
The vacuum degree of polycondensation is preferably 0.5 kPa or more. In the case of 0.5 kPa or more, the reactivity tends to be good, and the productivity is improved.

The polyester resin of the present invention can be dissolved in various solvents and used as a polyester solution. From the viewpoint of workability when used as a paint or a coating agent, the solution concentration is preferably 5 to 60% by mass, more preferably 15 to 45% by mass.
Moreover, as a solvent, methyl ethyl ketone and toluene are preferable and may be used individually by 1 type or may be used together 2 types. When using 2 types together, the range of methyl ethyl ketone / toluene = 1 / 9-9 / 1 is preferable.

Specific examples of the present invention will be described below, but the technical scope of the present invention is not limited to these examples.
The evaluation method shown in this example is as follows.

<Transparency evaluation method>
In a glass container, put 15 g of resin and 35 g of a mixed solvent of methyl ethyl ketone (MEK) / toluene (TOL) (mass ratio 1/1) (concentration 30 mass%) and let stand at 20 ° C. for 6 hours, using the following criteria: The result was visually observed and judged.
○: No turbidity ×: Turbidity

<Crushability evaluation method>
The resin after the normal pulverization process is passed through a sieve to obtain a resin powder that passes through 16 mesh and does not pass through 22 mesh. 10.00 g of this classified resin powder is precisely weighed and pulverized for 10 seconds in a trio blender The weight (A) g of the resin that does not pass is precisely weighed through a sieve of 30 mesh, and the residual ratio is obtained from the value of A according to the following formula, and this operation is performed three times and averaged. By using this grindability index, the grindability of the resin can be easily known, and the reproducibility of the numerical values is high. The pulverizability index of the polyester is preferably 80 or less.

(Formula-1)
((A) g / resin weight before crushing coffee mill (10.00 g)) × 100 = residual rate (%)

Example 1
Polyhydric carboxylic acid components, polyhydric alcohol components shown in Table 1 and 1500 ppm of antimony trioxide with respect to the total acid components were charged into a reaction vessel equipped with a distillation tower. In addition, the preparation composition of the polyhydric carboxylic acid component, the polyhydric alcohol component, and the isosorbide described in Table 1 is a mole part of each component when the total acid component is 100 mole parts.
Subsequently, the rotation speed of the stirring blade in the reaction vessel was maintained at 200 rpm, the temperature increase was started, and the temperature in the reaction system was heated to 265 ° C., and this temperature was maintained. After the esterification reaction is completed and no more water is distilled from the reaction system, the temperature in the reaction system is set to 250 ° C., the pressure in the reaction system is reduced over about 40 minutes, and the degree of vacuum is set to 0.5 kPa. The condensation reaction was conducted while distilling the diol component from the reaction system.
When the viscosity of the reaction system increases with the reaction and the stirring blade torque shows a predetermined torque, the stirring is stopped, the reaction system is returned to normal pressure, and the reaction product is taken out by pressurizing with nitrogen to obtain a polyester resin. It was.

(Examples 2-4, Comparative Examples 1-2)
A polyester resin was obtained in the same manner as in Example 1 except that the polyvalent carboxylic acid component and the polyhydric alcohol component were changed as shown in Table 1.

In Comparative Example 1, since the structural unit derived from trivalent or higher alcohol was not included, the grindability was insufficient.
In Comparative Example 2, the amount of the structural unit derived from trivalent or higher alcohol was large, so that the gel content was too high and the transparency was insufficient.

  The polyester resin of the present invention can be widely used for toners, coating materials, adhesives, films and the like.

Claims (3)

A polyester resin comprising 0.5 mol or more and 3 mol or less of a trivalent or higher alcohol-derived structural unit with respect to 100 mol of the acid-derived structural unit and having a resin gel content of 10% or less. The polyester resin according to claim 1, wherein the polyester resin has a peak top molecular weight of 30,000 or less. A method for producing a polyester resin, comprising a step of polycondensing a polyhydric alcohol component containing 0.5 to 3 mol of a trihydric or higher alcohol component with 100 mol of the acid component, and a polycarboxylic acid component.