JP5098238B2 - Polyester resin production method, polyester resin obtained by the production method, and toner resin using the resin - Google Patents

Description

  The present invention relates to a method for producing a polyester resin produced using an organotitanium compound as a catalyst, a polyester resin obtained by the production method, and a toner resin using the resin.

  Conventionally, as a polycondensation catalyst for producing a polyester resin, a tin-based catalyst such as dibutyltin oxide and an antimony catalyst such as antimony trioxide are generally used. Therefore, organic titanium compounds and aluminum compounds have been used as polyesterification catalysts other than the above compounds.

  However, since polyester resins produced using organotitanium compounds as a catalyst exhibit yellow to brown color, they are used for films and PET bottles that require transparency, and color toner resins that require a wide color reproduction range. As it was difficult to use.

  As a method of suppressing this coloring, a polyester resin production method (such as Patent Document 1) in which a phosphorus compound is added when producing a polyester resin, or a trihydric or higher alcohol is added to the polyhydric alcohol component of the polyester resin as a total alcohol. A method for producing a polyester resin for a toner to be used in an amount of 0.5 mol% to 50 mol% (Patent Document 2), and further, transesterification of a titanate ester as a catalyst with a diol component used in polyester in advance. There is a toner binder (Patent Document 3) polymerized by use.

However, according to the above-described method, although the coloring suppression effect is recognized, no effect is observed for the improvement in coloring of the already colored resin. Moreover, when using trivalent or more alcohol as a polyester component, since it has a crosslinked structure, it is not very suitable for a material which requires flexibility and workability such as a film. In addition, since the softening point is increased by crosslinking, when used as a toner resin, it has good offset resistance, but it is not preferable in terms of fixing properties, and its use amount is also limited, so coloring is not much suppressed. I cannot expect the effect.
JP-A-55-78018 Japanese Patent Publication No. 8-20765 JP 2002-148867 A

  The object of the present invention is to suppress the coloration of a polyester-based resin produced using an organotitanium compound as a catalyst, and to deteriorate the physical properties even when using a resin once colored or a raw material such as rosins that are markedly colored in the reaction. It is in providing the manufacturing method of the polyester-type resin which can aim at the improvement of the coloring without making it, and the polyester-type resin obtained by this manufacturing method.

  When the present inventors accidentally studied a polyester resin using an organotitanium compound as a catalyst, when a small amount of a trihydric or higher aliphatic polyhydric alcohol such as sorbitol was added after polymerization, the physical properties of the polyester resin As a result of finding out that the color tone of the colored resin is remarkably improved without deteriorating the color tone and maintaining the color tone even after removal, the present invention has been completed.

  The present invention relates to a method for producing a polyester resin using an organotitanium compound (a) as a catalyst, and after the polymerization of the polyester resin (A1), trivalent or higher aliphatic polyhydric alcohol (b) is added to the resin. 50-5000 ppm is added, It is a manufacturing method of the polyester-type resin characterized by the above-mentioned (1st invention).

  The present invention also relates to a method for producing a polyester resin using an organotitanium compound (a) as a catalyst, and after polymerization of a composite resin (A2) of a polyester resin and a vinyl resin, an aliphatic polyvalent having a valence of 3 or more. A method for producing a polyester-based resin, wherein the alcohol (b) is added in an amount of 50 to 5000 ppm based on the resin (second invention).

  In the present invention, the trivalent or higher aliphatic polyhydric alcohol (b) used in the first or second invention is at least one selected from the group consisting of sugar alcohol, trimethylolpropane, and trimethylolethane. There is (third invention).

  In the present invention, the trihydric or higher aliphatic polyhydric alcohol (b) used in the first to third inventions is selected from the group consisting of sorbitol, xylitol, mannitol, galactitol, erythritol, and glycerin among sugar alcohols. At least one kind (fourth invention).

  In the first to fourth inventions, the present invention uses the compound (c) having a skeleton derived from rosins as the polymerization component of the polyester resin (fifth invention).

  Moreover, this invention is a polyester-type resin obtained by 1st thru | or 5th invention (6th invention).

  The polyester resin in the sixth invention can be used as a resin component for toner (seventh invention).

  According to the present invention, even if the resin is once colored, the coloring can be remarkably improved by a simple method. Moreover, since the softness | flexibility of a resin is not spoiled or a softening point becomes high by bridge | crosslinking, the polyester-type raw material excellent in workability, a softness | flexibility, and an extensibility can be obtained. Furthermore, even when rosins are introduced into the resin skeleton, it is possible to obtain a resin having a low softening point with suppressed coloring. When used in a toner resin, the coloring can be improved while maintaining the fixability. In particular, in a polyester resin for a toner that requires low-temperature fixability, rosins are added to the polyester resin for the purpose of improving the fixability. Even if it is introduced as a polymerization component, the color tone can be improved, and therefore it can be suitably used as a resin component for a color toner.

  The polyester resin (A1), which is one of the polyester resins in the present invention, is obtained by reacting a carboxylic acid component and an alcohol component using the organic titanium compound (a) as a catalyst.

  As the organic titanium compound (a), any known organic titanium compound having a catalytic action called a transesterification catalyst, an esterification catalyst, or a polycondensation catalyst can be used. Specific examples include tetramethyl titanates, tetraethyl titanates, tetraisopropyl titanates, tetrabutyl titanates, tetra (2-ethylhexyl) titanates, tetraoctyl titanates, tetrastearyl titanates and their derivatives (multimers, hydrolysis). At least one of them can be selected and used, and the amount used is 0 with respect to the total amount of the carboxylic acid component and alcohol component used in the reaction system. It is preferable that it is 0.01 weight%-1.0 weight%.

  As the carboxylic acid component, a divalent or higher carboxylic acid which is a known polyester raw material is mainly used. Examples of divalent carboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, o-phthalic acid, or anhydrides or lower alkyl esters thereof; maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, etc. α, β-unsaturated dicarboxylic acids or anhydrides thereof; aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid and azelaic acid or anhydrides thereof; alkyl having 6 to 18 carbon atoms And succinic acid substituted with an alkenyl group or an anhydride thereof. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, tricarballylic acid, and anhydrides thereof.

  Moreover, monovalent carboxylic acid can be used for the purpose of adjusting the molecular weight and softening point of the resin as desired. Monovalent carboxylic acids include natural resin acids such as rosins described below or modified products thereof; aliphatic monocarboxylic acids such as octanoic acid, decanoic acid, dodecanoic acid, myristic acid, palmitic acid, stearic acid; benzoic acid, Aromatic monocarboxylic acids such as naphthalenecarboxylic acid or derivatives thereof can be mentioned.

  As the alcohol component, a divalent or higher alcohol, which is a known polyester raw material, is used mainly like the carboxylic acid component. Examples of the divalent alcohol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,6- Aliphatic or alicyclic dialcohols such as hexanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, cyclohexanedimethanol; polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) Propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene ( 2.0) -Polyoxyethylene (2.0) -2,2-bi (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) alkylene oxide adducts of bisphenol A such as propane and the like. Examples of the trivalent or higher alcohol component include trimethylolethane, trimethylolpropane, glycerin, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, 1,3,5-trihydroxymethylbenzene, etc. It is done.

  In addition, hydroxycarboxylic acids can also be used as necessary. Specific examples include p-hydroxybenzoic acid, citric acid, gallic acid and the like.

  For the polymerization of the polyester resin (A1), one or more monomer components composed of the above-mentioned carboxylic acid component and alcohol component are appropriately selected according to the required physical properties, and the OH excess is usually 0 to 0 by a conventional method. In the range of 20 mol%, in an inert gas stream, in the absence of a solvent or in the presence of a solvent, the reaction is carried out at a reaction temperature of 180 to 280 ° C. for 1 to 20 hours using an organotitanium compound (a) as a catalyst. It reacts for another 0.1 to 10 hours. In the present invention, after this polymerization, a trihydric or higher aliphatic polyhydric alcohol (b) is added and mixed until uniform.

  In addition, a composite resin (A2) of a polyester resin and a vinyl resin, which is another polyester resin in the present invention, reacts a carboxylic acid component and an alcohol component with an organic titanium compound (a) as a catalyst, Then, it is obtained by further polymerizing a vinyl monomer in the presence thereof.

For the polymerization of the vinyl monomer, any conventional method such as bulk polymerization, solution polymerization, suspension polymerization and the like can be applied, and the polymerization is performed at a temperature of 80 to 200 ° C. suitable for each polymerization method. Examples of vinyl monomers used in this case include aromatic monomers such as styrene, divinylbenzene, and α-methylstyrene; acrylic acid esters such as butyl acrylate and 2-ethylhexyl acrylate; methyl methacrylate and butyl methacrylate. Methacrylic acid ester; (anhydrous) maleic acid or its monoester, vinyl monomers having a carboxylic acid group such as acrylic acid and methacrylic acid. Examples of the polymerization initiator include organic peroxides such as di-t-butyl peroxide and azo initiators such as 2,2′-azobisisobutyronitrile. In the present invention, after this polymerization, a trihydric or higher aliphatic polyhydric alcohol (b) is added and mixed until uniform.

  The temperature at which the trihydric or higher aliphatic polyhydric alcohol (b) is added is preferably 100 to 200 ° C, more preferably 120 to 180 ° C. If it exceeds 200 ° C., crosslinking with the trihydric or higher aliphatic polyhydric alcohol (b) proceeds, which is not preferable.

The effect of adding the trihydric or higher aliphatic polyhydric alcohol (b) is the same whether the timing of the addition is immediately after polymerization or when it is melted again after removal. The addition amount is 50-5000 ppm with respect to the polyester resin (A1) or the composite resin (A2) of the polyester resin and the vinyl resin, and a coloring improvement effect is recognized, but an amount exceeding 5000 ppm is added. However, it is not preferable because no further effect can be expected, and depending on the alcohol used, dullness is generated in the resin. A more effective addition amount is preferably in the range of 100 ppm to 2000 ppm.

  Specific examples of the trihydric or higher aliphatic polyhydric alcohol (b) added after the polymerization include sugar alcohols such as sorbitol, xylitol, mannitol, iditol, galactitol, arabitol, ribitol, erythritol, and glycerin; trimethylol Examples include propane, trimethylolethane, pentaerythritol and the like. Among these, sorbitol, xylitol, mannitol, galactitol, erythritol, glycerin, trimethylolpropane, and trimethylolethane are particularly excellent in the effect of improving coloring, and sorbitol is more preferable.

When the compound (c) having a rosin-derived skeleton is used as the polymerization component of the polyester resin, the polyester can have a low softening point. When rosins are used as a component such as a polyester resin, there is a concern about coloring, but in the present invention, the coloring can be improved.

The compound (c) having a skeleton derived from rosins includes purified natural rosins such as gum rosin, wood rosin, tall oil rosin, and rosins such as hydrogenated rosin, disproportionated rosin and polymerized rosin modified from these A rosin ester obtained by esterifying the rosin acid with a polyhydric alcohol; and a reinforced rosin. Although the usage-amount of the compound (c) which has skeleton derived from rosins is not restrict | limited, 1 mol%-50 mol% of all the carboxylic acid components are preferable.

  In the reaction system according to the present invention, if necessary, a tetraalkylammonium hydroxide such as tetraethylammonium hydroxide; a diethylene glycol by-product inhibitor typified by an organic amine such as triethylamine, or an antioxidant such as an organic phosphorus compound. Arbitrary arbitrary additives can be mix | blended. Further, a transesterification catalyst such as magnesium acetate or zinc acetate may be used in combination with the organic titanium compound.

  The polyester resin thus obtained has little change in weight average molecular weight (Mw) before and after the addition of the trihydric or higher aliphatic polyhydric alcohol (b), and is colorless or light-colored, and various polyesters such as films and PET bottles. It can be used as a raw material for resin-based processed products. Moreover, since the thing using the compound (c) which has skeleton derived from rosins can aim at the low softening point, improving the coloring, as resin for hot-melt-adhesive agents which can be used at lower temperature Can be expected.

In particular, the polyester-based resin of the present invention can be suitably used as a toner resin, and can be particularly suitably used as a color toner resin that requires low-temperature fixability and transparency.

When the polyester resin of the present invention is used for the resin for toner, the carboxylic acid component constituting the polyester resin includes terephthalic acid, isophthalic acid, o-phthalic acid, maleic acid, fumaric acid, trimellitic acid, pyromellitic acid And succinic acid substituted with an alkyl group or alkenyl group having 6 to 18 carbon atoms, or anhydrides thereof, and gum rosin and hydrogenated rosin are preferable. Examples of the alcohol component include ethylene glycol, 1,2-propylene glycol, Aliphatic or cycloaliphatic dialcohols such as 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, cyclohexanedimethanol, pentaerythritol, trimethylolethane, trimethylolpropane; polyoxypropylene (2.2 ) -2,2-bis (4-G Roxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, poly Oxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, etc. And rosin esters obtained by esterifying gum rosin with a trihydric or higher polyhydric alcohol such as glycerin or pentaerythritol.

Further, when a composite resin of a polyester resin and a vinyl resin is used, preferable vinyl monomers include styrene, divinylbenzene, α-methylstyrene, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, methacrylic acid. Examples include butyl, (anhydrous) maleic acid or its monoalkyl ester, acrylic acid, and methacrylic acid. The ratio of the polyester resin component and the vinyl resin component in the polyester resin of the present invention is not particularly limited, but when used as a resin component for toner, preferably the polyester resin component / vinyl resin component = 50/50 to 90. / 10. When the ratio of the polyester resin component is less than 50%, the characteristics of the polyester resin are less likely to appear, and it becomes difficult to achieve both low-temperature fixability and blocking resistance when used as a toner. The vinyl resin is characterized by the improvement in wax dispersibility and chargeability, but if it is less than 10%, the effect of the composite cannot be expected.

  When used for toner resin, it is preferable that the softening point (Tm) is 90 to 170 ° C., the glass transition temperature (Tg) is 40 to 70 ° C., and the acid value is 0.5 to 50 mgKOH / g. When the softening point is less than 90 ° C., the low-temperature fixability is good, but the blocking resistance is poor, while when it exceeds 170 ° C., the low-temperature fixability is poor. Further, if the glass transition temperature is less than 40 ° C., the low-temperature fixability is good, but the blocking resistance is extremely poor, and even if an inorganic powder such as silica is added, it cannot be used. On the other hand, if it exceeds 70 ° C., the low-temperature fixability becomes poor. When the acid value is less than 0.5 mgKOH / g, the dispersibility of the colorant such as a pigment is lowered. On the other hand, when it exceeds 50 mgKOH / g, the negative charge increases and the temperature dependence of the charge increases. The environmental stability of is poor.

  The polyester resin obtained by the present invention can be used in other applications such as toner resin, if necessary, within a range not impairing the performance of the present invention, other polyester resins, styrene resins, (meth) acrylic resins. A styrene acrylic resin, a styrene maleic acid resin, a phenol resin, an epoxy resin, a polyurethane resin, a petroleum resin, an olefin resin, or a composite resin thereof can be used in combination.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, these Examples do not limit this invention. In the examples and comparative examples, “parts” and “%” mean parts by weight and% by weight.
(Evaluation of basic physical properties and performance test of polyester resin)
Measured by molecular weight gel permeation chromatography (GPC). The molecular weight measurement conditions by GPC are as follows.
Device: HLC-8220 manufactured by Tosoh Corporation
Column: TSKgel GMHxl + GMHxl-1
Measurement temperature: 40 ° C
Sample solution: 0.1 wt% tetrahydrofuran solution solution injection amount: 100 μl
Detection device: Refractive index detector The molecular weight calibration curve was prepared using standard polystyrene.

2. Glass transition temperature (Tg)
The temperature was raised to 150 ° C. using a differential scanning calorimeter (SII Nano Technology Co., Ltd .: DSC-22), allowed to stand at that temperature for 10 minutes, and then cooled to 10 ° C. at a temperature drop rate of 10 ° C./min. After standing at that temperature for 10 minutes, when measured at a heating rate of 10 ° C./min, an extension of the baseline below the glass transition temperature and a tangent line indicating the maximum slope from the peak rising portion to the peak apex The temperature at the point of intersection was taken as the glass transition temperature (Tg).

3. Softening point (Tm)
Using a Koka type flow tester (manufactured by Shimadzu Corporation: CFT-500D), a 1 g sample was heated at a heating rate of 4 ° C./min. A nozzle with a thickness of 1 mm is pushed out, thereby drawing a plunger tester drop amount (flow value) -temperature curve of the flow tester. When the height of the S-shaped curve is h, the temperature corresponding to h / 2 (resin The temperature at which half flows out) is taken as the softening point.

4. Acid value (AV)
2 g of the sample was dissolved in 50 ml of tetrahydrofuran (THF), a few drops of a phenolphthalein / ethanol solution was added as an indicator, and titration was performed with a 1/10 N normal aqueous KOH solution. The end point was the time when the color of the sample solution was purple, and the acid value (KOHmg / g) was calculated from this titration amount and the sample mass.

5. Color tone A 50% toluene solution of the sample resin was measured with a Gardner colorimeter. From a practical aspect, it is preferably 5 or less.

Synthesis of polyester resin (A1) <Example 1>
In a reaction vessel equipped with a thermometer, Liebig condenser, stirrer and nitrogen inlet, 155 parts terephthalic acid, 155 parts isophthalic acid, 688 parts bisphenol A propylene oxide adduct 688 parts, and 2 parts tetraisopropyl titanate The reaction was carried out at 240 ° C. for 8 hours while the produced water was distilled out of the reaction system in a nitrogen atmosphere under normal pressure, and further reacted for 8 hours under a reduced pressure of 10 hPa. After completion of the reaction, the pressure was restored to normal pressure, and 0.1 part of sorbitol was added when the internal temperature reached 145 ° C. After confirming that it was uniformly dispersed, 938 parts of a polyester resin (Pes-A) was obtained from the reaction vessel. The weight average molecular weight (Mw) was 9500, Tg was 60 ° C., Tm was 107 ° C., and AV was 4 KOH mg / g.

<Example 2>
940 parts of a polyester resin (Pes-B) was obtained by the same reaction tank, composition and operation as in Example 1 except that the amount of sorbitol used in Example 1 was 1.5 parts. The weight average molecular weight (Mw) was 9500, Tg was 60 ° C., Tm was 107 ° C., and AV was 4 KOH mg / g.

<Example 3>
In a reaction vessel equipped with a thermometer, separator, Liebig condenser, stirrer and nitrogen inlet, 262 parts terephthalic acid, 262 parts isophthalic acid, 215 parts gum rosin, 39 parts ethylene glycol, 156 parts 1,2-propylene glycol Then, 66 parts of neopentyl glycol and 0.8 part of tetrabutyl titanate were charged, and the reaction was carried out for 10 hours while gradually raising the temperature at 190 ° C. to 240 ° C. under normal pressure, and water produced at that time was distilled out of the reaction system. Furthermore, it reacted at 230 degreeC under reduced pressure of 10 hPa for 5 hours. After completion of the reaction, the pressure was restored to normal pressure, and 0.4 part of sorbitol was added when the internal temperature reached 145 ° C. After confirming that it was uniformly dispersed, 850 parts of a polyester resin (Pes-C) was obtained from the reaction vessel. The weight average molecular weight (Mw) was 3700, Tg was 57 ° C., Tm was 102 ° C., and AV was 35 KOH mg / g.

<Examples 4 to 10>
The same composition as in Example 3 except that sorbitol used in Example 3 was replaced with xylitol, erythritol, galactitol, mannitol, trimethylolpropane, trimethylolethane, and glycerin, respectively. , And operation, 850 parts of polyester resins (Pes-D to Pes-J) were obtained. All the polyester resins had a weight average molecular weight of 3700, Tg of 57 ° C., Tm of 102 ° C., and AV of 35 KOH mg / g.

<Example 11>
In Example 3, without removing sorbitol, once taken out and pelletized, 850 parts were melted again at 180 ° C., and 0.4 parts of sorbitol was added when completely melted. After confirming that it was uniformly dispersed, 850 parts of a polyester resin (Pes-K) was obtained from the reaction vessel. The weight average molecular weight (Mw) was 3700, Tg was 57 ° C., Tm was 102 ° C., and AV was 35 KOH mg / g.

Synthesis of Composite Resin (A2) of Polyester Resin and Vinyl Resin <Example 12>
In a reaction vessel equipped with a thermometer, separator, Liebig condenser, stirrer and nitrogen inlet, 262 parts terephthalic acid, 262 parts isophthalic acid, 7.5 parts fumaric acid, 219 parts gum rosin, 40 parts ethylene glycol, 1 , 2-Propylene glycol (159 parts), Neopentyl glycol (67 parts) and Tetrabutyl titanate (0.8 parts) were added and reacted for 10 hours at 190 ° C to 240 ° C under normal pressure. Distilled out of the system. Furthermore, it reacted at 230 degreeC under reduced pressure of 10 hPa for 5 hours. After the completion of the reaction, the pressure was restored to normal pressure and taken out from the reaction vessel to obtain 860 parts of a polyester resin.
Next, 750 parts of the above polyester resin was charged into a reaction vessel equipped with a Dimroth condenser, stirrer and nitrogen inlet tube prepared separately from the reaction vessel used for the reaction of the polyester resin, and the internal temperature after heating and melting was 140 ° C. Adjusted. Thereafter, a mixture of 200 parts of styrene, 50 parts of butyl acrylate, and 0.8 part of di-t-butyl peroxide (manufactured by NOF Corporation: trade name Perbutyl D) as a radical polymerization initiator was dropped over 30 minutes. After the completion, the temperature was kept for 8 hours, and further the pressure was reduced at an internal temperature of 180 ° C. for 3 hours to distill away the volatile matter. After completion of the reaction, 0.4 parts of sorbitol was added when the pressure was restored to normal pressure. After confirming uniform dispersion, the product was taken out from the reaction vessel to obtain 995 parts of a polyester resin (Pes-L). The weight average molecular weight (Mw) was 14000, Tg was 59 ° C., Tm was 110 ° C., and AV was 26 KOH mg / g.

<Comparative Example 1>
In Example 1, without taking sorbitol, it was taken out from the reaction vessel as it was, and 938 parts of a polyester resin (Pes-M) was obtained. The weight average molecular weight (Mw) was 9500, Tg was 60 ° C., Tm was 107 ° C., and AV was 4 KOH mg / g.

<Comparative example 2>
In Example 3, it was taken out from the reaction vessel as it was without adding sorbitol, and 850 parts of a polyester resin (Pes-N) was obtained. The weight average molecular weight (Mw) was 3700, Tg was 57 ° C., Tm was 102 ° C., and AV was 35 KOH mg / g.

<Comparative Example 3>
In Example 3, except that the amount of sorbitol added was 0.03 part, 850 parts of a polyester-based resin (Pes-O) was obtained by the same operation as in Example 3. The weight average molecular weight (Mw) was 3700, Tg was 57 ° C., Tm was 102 ° C., and AV was 35 KOH mg / g.

<Comparative example 4>
In Example 3, 858 parts of polyester resin (Pes-P) was obtained in the same manner as in Example 3 except that the amount of sorbitol added was 8 parts. The weight average molecular weight (Mw) was 3700, Tg was 57 ° C., Tm was 102 ° C., and AV was 35 KOH mg / g. The resulting resin was dull.

<Comparative Example 5>
In Example 3, 850 parts of a polyester resin (Pes-Q) was obtained in the same manner as in Example 3, except that 0.4 part of ethylene glycol was added instead of sorbitol. The weight average molecular weight (Mw) was 3700, Tg was 57 ° C., Tm was 102 ° C., and AV was 35 KOH mg / g.

<Comparative Example 6>
In Example 12, without taking sorbitol, it was taken out from the reaction vessel as it was to obtain 995 parts of a polyester resin (Pes-R). The weight average molecular weight (Mw) was 14000, Tg was 59 ° C., Tm was 110 ° C., and AV was 26 KOH mg / g.

  Table 1 shows the color tones of the polyester resins Pes-A to Pes-R obtained in Examples 1 to 12 and Comparative Examples 1 to 6.

(Toner evaluation)
Evaluation as a resin for toner was performed using the polyester resins Pes-A, C, K, L and Pes-M to R obtained in Examples 1, 3, 11, 12 and Comparative Examples 1 to 6 above. Toner was prepared and the color tone was evaluated.

<Adjustment of evaluation toner>
100 parts of polyester resin for toner of the present invention (Pes-A, C, K, L) or 100 parts of polyester resin for comparison toner (Pes-M to R), 5 parts of carbana wax, and yellow pigment (manufactured by Clariant Corporation: 4 parts of toner yellow HG VP2155) were mixed with a blender, and melt-kneaded with a biaxial extruder heated to 130 degrees. The cooled kneaded product is coarsely pulverized with a speed mill and then finely pulverized with a jet mill. The resulting finely pulverized product is strictly classified with a multi-division classifier using a core under effect, and a toner having a weight average particle size of 8 μm. Particles were obtained. Next, 0.5 parts of colloidal silica (manufactured by Nippon Aerosil Co., Ltd .: Aerosil R972) is mixed with 100 parts of the obtained toner particles by a mixer, and the toner (T-1 to 4) and the comparative toner (T -5 to 10). The color tone evaluation of the obtained toner and the comparative toner was performed according to the following method. The evaluation results are shown in Table 2.

<Evaluation method>
1. Color tone Using a fixing device of a commercially available color copying machine (manufactured by Canon: CLC-500), the image was developed and fixed on an OHP film, a fixed image was transcribed with an overhead projector, and the color tone was visually judged.
Judgment criteria ○: Vivid color development △: Slightly dull yellow ×: Dull

As is clear from the results shown in Table 1, the polyester resins obtained in Examples 1 to 12 all have good color tone and change to a weight average molecular weight and other physical properties as compared with the corresponding comparative examples. It can be seen that only the color tone is improved. Further, the toner prepared using the polyester resin of the present invention is excellent in color tone as a color toner as shown in Table 2 (Evaluation Examples 1 to 4).

However, a polyester-based resin in which trivalent or higher aliphatic polyhydric alcohol is not added, or a necessary amount is not added, or an alcohol other than trihydric or higher aliphatic polyhydric alcohol defined in the present invention is added. The coloring could not be improved to a level satisfying (Comparative Examples 1-3, 5, 6), and the resin added with sorbitol more than necessary was found to be dull in the resin (Comparative Example 4). Even when they are used as toners, the color tone as a color toner cannot be satisfied (Comparative Evaluation Examples 1 to 6).

Since the polyester resin of the present invention is excellent in color tone even when polymerized using an organotitanium compound as a catalyst, it is used for various types of polyester processing substrates such as films and PET bottles, plastic molding materials and paints, and pigment master batches such as polymerized toners. Use as a binder for resins, hot-melt adhesives, inks, and toners can be expected.

Claims (5)

  A method for producing a polyester-based resin using an organotitanium compound (a) as a catalyst, wherein after the polymerization of the polyester resin (A1), a trihydric or higher aliphatic polyhydric alcohol (b) is added to the resin in an amount of 50 to 5000 ppm. Then, the value in the Gardner colorimeter of the 50% toluene solution of this resin shall be 5 or less, The manufacturing method of the polyester-type resin characterized by the above-mentioned.   A method for producing a polyester resin using an organotitanium compound (a) as a catalyst, wherein after the polymerization of a composite resin (A2) of a polyester resin and a vinyl resin, a trivalent or higher aliphatic polyhydric alcohol (b) is added. A method for producing a polyester-based resin, comprising adding 50 to 5000 ppm to the resin so that the value of a 50% toluene solution of the resin is 5 or less in a Gardner colorimeter.   The production of a polyester-based resin according to claim 1 or 2, wherein the trihydric or higher aliphatic polyhydric alcohol (b) is at least one selected from the group consisting of sugar alcohol, trimethylolpropane, and trimethylolethane. Method. Trivalent or more aliphatic polyhydric alcohol (b) is sorbitol of sugar alcohol, xylitol, mannitol, galactitol, is at least one erythritol is selected from the group consisting of glycerol, any of claims 1 to 3 method for producing a polyester resin according to any one of claims. The manufacturing method of the polyester-type resin of any one of Claims 1 thru | or 4 which uses the compound (c) which has skeleton derived from rosins for the polymerization component of a polyester-type resin.