JPH0812471B2 - Toner resin and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a resin for toner which is excellent in low-temperature fixing property, non-offset property and anti-blocking property, and a method for producing the same.

<Prior Art> As a resin used as a binder for toner, a cross-linking resin or a non-cross-linking resin composed of an ultra-high molecular weight polymer and an ultra-low molecular weight polymer can be mentioned. This 2
Comparing the two, the latter is superior in that non-offset property, low temperature fixing property and blocking resistance, which are important physical properties of the toner, can be controlled independently, and most of the conventional styrene-acrylic toners are used. Uses a binder belonging to the latter type.

On the other hand, in recent years, along with the demand for higher speed of copy machines and demand for polyvinyl chloride plasticizer resistance of toners, polyester binders have attracted attention, and polyester binders having various structures have been developed. However, the conventional one is a cross-linked polyester resin using a polyfunctional monomer, and therefore it is difficult to satisfy all of non-offset property, low temperature fixing property and blocking resistance as toner performance. For example, try to improve low temperature fixing property. If so, the non-offset property is deteriorated and the anti-blocking property is deteriorated, and as a result, there is a problem that the speeding up of copying cannot be achieved.

On the other hand, as the polyester that can easily satisfy the toner performance, a method of obtaining a non-crosslinked polyester resin composed of an ultrahigh molecular weight polyester resin and an ultralow molecular weight polyester resin can be considered as described above. In the bulk condensation polymerization method used as a polymerization method of, since the melt viscosity of the polymerization system becomes extremely high when trying to obtain a linear ultra-high molecular weight polyester, mixing and stirring in the polymerization system and At present, it is very difficult to take out and industrial production is not possible.

<Problems to be Solved by the Invention> An object of the present invention is to provide a method for producing a polyester resin capable of obtaining a toner excellent in low-temperature fixing property, non-offset property and anti-blocking property. To do.

<Means for Solving Problems> The gist of the present invention is that the glass transition temperature is 50 ° C.
100 parts by weight of a crosslinked polyester resin (a) having a softening temperature of 200 ° C. or lower, and 0.5 to 80 parts by weight of a linear polyester resin (b) having a softening temperature of 150 ° C. or lower and a weight average molecular weight of 3,000 to 50,000. A resin for toner consisting of 100 parts by weight of a crosslinked polyester resin (a) having a glass transition temperature of 50 ° C. or higher and a softening temperature of 200 ° C. or higher, and a softening temperature of 150 ° C. or lower and a weight average molecular weight of 3,000 to 50,000. There is provided a method for producing a resin for toner, which comprises mixing 0.5 to 80 parts by weight of a certain linear polyester resin (b) within a temperature range of the softening temperature of the linear polyester resin (b) to 230 ° C. .

As a result of intensive studies by the present inventors, it is very difficult to obtain a linear high molecular weight polyester as described above for producing an ultra high molecular weight polyester resin, but it is relatively easy to obtain a crosslinked high molecular weight polyester. Thing, ultra low molecular weight polyester that can be manufactured by conventional technology, polyester bond,
Generally, it decomposes and recombines easily at high temperatures.
Stable in the temperature range of 0 ℃ or less, if the glass transition temperature of the ultra high molecular weight polymer that is the main component of the resin for toner is 50 ℃ or more, the toner does not cause blocking at room temperature, ultra low molecular weight polymer Is to impart fluidity to the toner, and the weight average molecular weight is preferably in the range of 3,000 to 50,000 or less, and 100 parts by weight of the crosslinked polyester which is an ultrahigh molecular weight polymer has a low molecular weight polymer of 0.5
It has been found that a range of 80 to 80 parts by weight is suitable. The present invention is constructed based on this, but in order for the present invention to exert its effect, the ultrahigh molecular weight polyester is (1) a crosslinked polyester and (2) has a glass transition from the viewpoint of blocking resistance. The temperature is 50 ° C or higher, preferably
The melting point must be 60 ° C or higher, and the softening point must be 200 ° C or lower, preferably 180 ° C or lower in melt mixing with the low molecular weight polymer in the stable region of (3) ester bond. The ultra low molecular weight polymer has a weight average molecular weight of 3,000 to 50,000, preferably 5,000 to 20,000 from the viewpoint of (4) imparting fluidity.
(5) From the viewpoint of low-temperature fixing, the softening temperature must be 150 ° C. or lower, preferably 130 ° C. or lower. Furthermore, for the non-offset property, the property of the crosslinked polyester which is an ultra-high molecular weight polyester is used, for the low temperature fixing property, the property of the low molecular weight polyester is used, and in order to use it as a toner resin having excellent blocking resistance, (6) The linear polyester resin (b) must be added in an amount of 0.5 to 80 parts by weight, preferably 3 to 30 parts by weight, based on 100 parts by weight of the crosslinked polyester resin (a). Further, it is preferable that the temperature at the time of compounding is higher, but the temperature should not be 230 ° C. or higher at which recombination of the monomer components occurs.

To produce the crosslinked polyester resin usable in the present invention, at least one carboxylic acid component having a valence of 3 or more and / or
Alternatively, a trivalent or higher valent alcohol component, a bifunctional carboxylic acid component and a diol component may be polycondensed according to a conventional method. Here, the trivalent or higher carboxylic acid component is a trivalent or higher carboxylic acid, or an acid anhydride thereof or a lower alkyl ester thereof, and three or more --COOH in one molecule.
A substance having a group or three or more groups present in one molecule
A substance in which one or more pairs of COOH groups are acid anhydrides or 1
Of the three or more --COOH groups present in the molecule, one or more is a substance in which an ester of a lower alcohol is formed. For example, 1,2,4-benzenetricarboxylic acid, 1,2,4-
Cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,
2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,2,7,8-octanetetracarboxylic acid or their acid anhydrides or their methyl esters, ethyl esters, propyl esters, isopropyl esters And lower alcohol esters having a boiling point of 200 ° C. or less.

The bifunctional carboxylic acid component is a divalent carboxylic acid, an acid anhydride thereof, or a lower alkyl ester thereof, which is a substance having two --COOH groups in one molecule, an acid anhydride of the substance, or one molecule of the substance. Two -COOH present in the
One or more of the groups is a substance in which an ester of a lower alcohol is formed. Examples of this are maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, linolein. Acid or its acid anhydride or its monomethyl ester, dimethyl ester, monoethyl ester, diethyl ester, methyl ethyl ester, monopropyl ester, dipropyl ester, methylpropyl ester, ethylpropyl ester, etc. The monoester or diester is mentioned, but the present invention is not limited thereto.

Further, the trivalent or higher alcohol component is a compound having three or more hydroxyl groups in one molecule, and examples thereof include 1,1,1-trimethylolethane, pentaerythritol, glycerin, and 1,1,1-trimethylolpropane. , 1,1,4,4-tetramethylolbutane, 1,2,4-trihydroxybutane, etc., among which pentaerythritol and glycerin are useful.

In the present invention, the diol component is a substance having two —OH groups in one molecule, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol,
Alkylene glycols such as 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, cyclohexanedimethanol, neopentyl glycol and 1,4-butenediol, bisphenol A, hydrogenated bisphenol A, Polyoxypropylene-2,2-bis (4
-Hydroxyphenyl) propane, polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane, 2,
2 '-(1,4-phenylenebisoxy) bisethanol,
1,1'-dimethyl-2,2 '-(1,4-phenylenebisoxy) bisethanol, 1,1,1', 1'-tetramethyl-2,
Aromatic diols such as 2 '-(1,4-phenylenebisoxy) bisethanol are listed, but the present invention is not limited thereto.

As described above, the crosslinked polyester (a) can be obtained by combining an arbitrary acid component and alcohol component depending on the purpose, but the following polyesters, whose crosslinking degree is easily controlled and whose softening temperature is low, are particularly preferable.

(1) trimellitic acid 2 to 30 mol%, terephthalic acid 10 to
A polyester obtained from an acid component consisting of 70 mol% and isophthalic acid of 0 to 88 mol% and an alcohol component consisting of at least one selected from ethylene glycol and aromatic diols.

(2) 20-80 mol% terephthalic acid, 20-80 isophthalic acid
Acid component consisting of mol% and pentaerythritol 1-50
Mol% and ethylene glycol 70 to 99 mol%, or glycerin 2 to 50 mol% and ethylene glycol 50 to 98
Polyester obtained from alcohol component consisting of mol%.

As a catalyst for the esterification and condensation reaction, conventionally used antimony trioxide, dibutyltin oxide, tetrabutoxy titanate, zinc acetate, manganese acetate, calcium acetate, magnesium acetate, germanium dioxide, etc. can be mentioned. It is not limited to these.

Further, the linear polyester (b) can be produced by polycondensing a bifunctional carboxylic acid component and a diol by a conventional method. As the bifunctional carboxylic acid component and the diol component constituting the polyester, the same ones as described above can be used.
A polyester obtained by condensing an acid component consisting of -80 mol% and isophthalic acid of 20-80 mol% and ethylene glycol is particularly useful because it can lower the softening temperature without lowering the glass transition temperature.

The softening point of the toner resin in the present invention is CFT-5.
Using a 00 type flow tester (manufactured by Shimadzu Corp.), the temperature was measured when the resin flowed out 1/2 under the conditions of a heating rate of 3 ° C./min, a load of 30 kgf, and a nozzle of 1 mmφ × 10 mm. (The amount of the sample loaded into the cylinder is 1.5 ml.) The glass transition temperature was measured by a differential scanning calorimeter (DSC), and the weight average molecular weight was measured by gel permeation chromatography (GPC). Further, the resin according to the present invention as a binder for toner may be mixed with other binders and additives such as an anti-blocking agent and a charge control agent as long as the performance is not impaired. Examples of the resin that can be mixed include other polyester resins and styrene-
An acrylic resin, an epoxy resin, etc. are mentioned.

Next, the present invention will be described in more detail with reference to representative examples, but the present invention is not limited to these examples.
The parts in the examples and comparative examples are parts by weight unless otherwise specified.

Example 1 (Synthesis of cross-linked polyester) Raw materials and a catalyst were charged into an autoclave having a tachometer, a torque meter and a distillation column in accordance with the proportions shown in Table 1, and the temperature was gradually raised to distill the produced water from the distillation column. While carrying out the esterification reaction.

When no more water was distilled from the distillation column, the distillation column was removed from the autoclave, and then the pressure inside the autoclave was reduced to 1 Torr by a vacuum pump to distill the free alcohol produced by the condensation reaction out of the system. At this time, the temperature of the reaction liquid was 250 ° C., the rotation speed of the stirring blade was 100 rpm, and the stirring torque at the start of condensation was 0.4 kg-cm. After 128 minutes, the torque rose to 0.8 kg-cm, so the degree of vacuum inside the autoclave was adjusted to 50 Torr and kept for 27 minutes.The torque reached 12 kg-cm, so the pressure inside the autoclave was reduced to normal pressure. Returned to stop the reaction. Then, the lid of the autoclave was opened, the contents were cooled with water, dried and pulverized to obtain crosslinked polyester powder. The resulting polymer was mixed with chloroform (25 ° C) but did not dissolve,
The composition of the polymer after decomposition was analyzed by liquid chromatography and gas chromatography, and the results shown in Table 2 were obtained.

The softening temperature of the polymer was 148 ° C and the glass transition temperature by DSC was 71 ° C.

(Ingredients for linear polyester) According to the ratios in Table 3, the raw materials and the catalyst were charged into the autoclave used in (Synthesis of crosslinked polyester), the temperature was gradually raised, and the produced water was distilled from the distillation column. The esterification reaction was carried out.

When no more water was distilled from the distillation column, the distillation column was removed from the autoclave, the pressure inside the autoclave was reduced to 1 Torr by a vacuum pump, and the free alcohol generated by the condensation reaction was distilled out of the system. At this time, the reaction temperature was 280 ° C., the rotation speed of the stirring blade was 100 rpm, and the stirring torque at the start of condensation was 0.4 kg-cm. When 67 minutes passed from the start of condensation, the stirring torque reached 2.0 kg-cm,
The pressure in the autoclave was returned to normal pressure, the contents were taken out, cooled with water, dried and pulverized to obtain a linear polyester powder. The softening temperature of the polymer was 118 ° C, the weight average molecular weight by GPC was 28500, and the glass transition temperature by DSC was 53 ° C. As a result of composition analysis, the constituent components of the polymer were as shown in Table 4.

(Production of resin for toner) 20 parts of linear polyester resin powder was kneaded with 100 parts of the crosslinked polyester resin powder synthesized above with a screw extruder heated to 180 ° C, and the discharged resin mixture was water-cooled and dried. It was pulverized to obtain a resin for toner.

(Evaluation of Toner Resin) 95 parts of the toner resin and 5 parts of carbon black are melt-kneaded by a twin-screw extruder, cooled, finely pulverized by a jet mill, and classified by a zigzag classifier to obtain an average particle size of 10.2 microns. Toner was obtained. To 5 parts of this toner, 95 parts of iron powder carrier was added, and an electrostatic charge image was developed using an electrophotographic copying machine for polyester toner (which enables the fixing temperature to be changed). When continuous copying of 5000 sheets was performed at a speed of 50 sheets per minute, a good image without fog was obtained. Other properties are shown in Table 18.

Example 2 (Synthesis of Crosslinked Polyester) The same operation as (Synthesis of crosslinked polyester) in Example 1 was carried out except that raw materials and a catalyst were charged based on Table 5 to obtain a crosslinked polyester resin powder.

The obtained resin powder did not dissolve in chloroform and was confirmed to be a crosslinked polymer. The polymer had a softening temperature of 139 ° C. and a glass transition temperature by DSC of 68 ° C. As a result of compositional analysis, the polymer was composed of the components shown in Table 6.

(Production of Resin for Toner) To 100 parts of the obtained crosslinked polyester, 10 parts of the linear polyester synthesized in Example 1 was treated in the same manner as in Example 1 to obtain a resin for toner.

(Evaluation of Toner Resin) By the same method as in Example 1, a toner having an average particle size of 11.5 μm was obtained. This was loaded into the copying machine used in Example 1,
When continuous copying was performed at 5000 sheets at a speed of 50 sheets per minute, a clear image without fog was obtained. No. 18 other characteristics
Shown in the table.

Example 3 (Synthesis of Crosslinked Polyester) The same operation as (Synthesis of crosslinked polyester) in Example 1 was carried out except that raw materials and a catalyst were charged based on Table 7 to obtain a crosslinked polyester resin powder.

The obtained resin powder did not dissolve in chloroform and was confirmed to be a crosslinked polymer. The softening temperature of the polymer was 131 ° C and the glass transition temperature by DSC was 69 ° C. As a result of compositional analysis, the polymer was composed of the components shown in Table 8.

(Synthesis of Linear Polyester) After starting the condensation reaction, the same as Example 1 (synthesis of linear polyester) except that the pressure in the autoclave was returned to normal pressure when the stirring torque reached 1.2 kg-cm. The operation was performed to obtain a linear polyester powder. The softening temperature of the polymer was 106 ° C., the weight average molecular weight by GPC was 11800, the glass transition temperature by DSC was 52 ° C., and the results of composition analysis were the same as in Example 1.

(Production of Resin for Toner) To 100 parts of the obtained crosslinked polyester, 3 parts of linear polyester was treated in the same manner as in Example 1 to obtain a resin for toner.

(Evaluation of Toner Resin) The toner resin 95 parts and the carbon black 5 parts are
After melt-kneading with a shaft extruder and cooling, the mixture was finely pulverized with a jet mill and classified with a zigzag classifier to obtain a toner having an average particle size of 11.3 microns. To 5 parts of this toner, 95 parts of iron powder carrier was added, and an electrostatic charge image was developed using an electrophotographic copying machine for polyester toner (which can change the fixing temperature). When continuous copying of 5000 sheets was performed at a speed of 50 sheets per minute, a good image without fog was obtained. Other properties are shown in Table 18.

Example 4 (Synthesis of Crosslinked Polyester) Based on Table 9, Example 1 (Synthesis of crosslinked polyester) except that raw materials and a catalyst were charged and the reaction system was returned to normal pressure when the stirring torque reached 16 kg-cm. The same operation as the above) was performed to obtain a crosslinked polyester resin.

The obtained resin powder did not dissolve in chloroform and was confirmed to be a crosslinked polymer. The softening temperature of the polymer was 168 ° C and the glass transition temperature by DSC was 75 ° C.

(Synthesis of Linear Polyester) Example 1 (Synthesis of linear polyester) except that raw materials and a catalyst were charged based on Table 10 and the reaction system was returned to normal pressure when the stirring torque reached 3 kg-cm. The same operation as the above) was performed to obtain a linear polyester. The softening temperature of the polymer is 103 ° C., the weight average molecular weight by GPC is 24500, DSC.
Glass transition temperature was 46 ° C.

(Production of Toner Resin) To 100 parts of the obtained crosslinked polyester, 50 parts of linear polyester was treated in the same manner as in Example 1 to obtain a resin for toner.

(Evaluation of Toner Resin) 95 parts of the toner resin and 5 parts of the carbon black are 2 parts.
The mixture was melt-kneaded by a shaft extruder, cooled, finely pulverized by a jet mill, and classified by a zigzag classifier to obtain a toner having an average particle size of 9.1 μm. Iron powder carrier for 5 parts of this toner
After adding 95 parts, an electrostatic charge image was developed using an electrophotographic copying machine for polyester toner (one capable of changing the fixing temperature). When continuous copying of 5000 sheets was performed at a speed of 50 sheets per minute, good images without fog were obtained. Other properties are shown in Table 18.

Comparative Example 1 (Production of Resin for Toner) Example 3 except that the crosslinked polyester was used alone.
A resin for toner was obtained by the same method as described above.

(Evaluation of Toner Resin) As a result, at a speed of 50 sheets per minute, the toner fixability was poor and copying was not possible. When continuous copying of 1,000 sheets was performed at a speed of 25 sheets per minute, an image free of fog was obtained, but it was found that the fixing strength was too small to be practical.

Comparative Examples 2 to 3 The same experiment as in Example 1 was carried out except that the raw materials for the crosslinked polyester resin were charged according to Table 11.

The composition and thermal analysis of the obtained crosslinked polymer were as shown in Table 12.

Using the crosslinked polymer and the linear polymer used in Example 1, a toner was manufactured in the same manner as in Example 1, and the characteristics of the toner were examined. Table 18 shows the results.

Comparative Examples 4 to 5 The same experiment as in Example 2 was carried out except that the linear polyesters shown in Table 13 were used. The results are shown in Table 18.

Comparative Examples 6 to 7 The same experiment as in Example 2 was carried out except that the raw materials for the crosslinked polyester were charged according to Table 14.

When the composition analysis and the thermal analysis of the obtained crosslinked polymer were performed, the results shown in Table 15 were obtained.

Using the polymer, a toner was manufactured in the same manner as in Example 2 and its characteristics were examined. The results are shown in Table 18.

Comparative Example 8 The same experiment as in Example 3 was carried out except that the raw materials for the crosslinked polyester were charged according to Table 16.

When the composition analysis and the thermal analysis of the obtained crosslinked polymer were performed, the results shown in Table 17 were obtained.

Using the polymer, a toner was manufactured in the same manner as in Example 3 and its characteristics were examined. The results are shown in Table 18.

<Effects of the Invention> The conventional polyester-based electrophotographic toner using the cross-linkable polyester resin alone as the binder has a limit in increasing the copying speed, but the toner using the toner resin according to the present invention is not limited to the examples. As shown, it is possible to greatly increase the copy speed. This brings the efficiency of the electrostatic copying work, and the effect can be said to be extremely large.

Claims (10)

[Claims] 1. A glass transition temperature of 50 ° C. or higher and a softening temperature of 20.
100 parts by weight of crosslinked polyester resin (a) having a temperature of 0 ° C. or lower,
And a softening temperature of 150 ° C or less and a weight average molecular weight of 3,000 to 5
0.5 to 80 parts by weight of the linear polyester resin (b), which is 0,000, is added to the softening temperature of the linear polyester resin (b) of 230
A method for producing a toner resin, which comprises mixing in a temperature range of ℃ or less. 2. The acid component of the linear polyester resin (b) is 20 to 80 mol% of terephthalic acid and 20 to 80 mol% of isophthalic acid.
The method for producing a toner resin according to claim 1, wherein the diol component is ethylene glycol. 3. The acid component of the crosslinked polyester resin (a) is 2 to 30 mol% of trimellitic acid, 10 to 70 mol% of terephthalic acid and 0 to 88 mol% of isophthalic acid, based on all acid components,
The method for producing a resin for toner according to claim 1, wherein the alcohol component is at least one selected from ethylene glycol and aromatic diol. 4. The acid component of the crosslinked polyester resin (a) comprises 20 to 80 mol% terephthalic acid and 20 to 80 mol% isophthalic acid, and the alcohol component is pentaerythritol 1 to 50.
The method for producing a resin for toner according to claim 1, characterized in that the resin comprises 70% by mol of ethylene glycol and 70-99% by mol of ethylene glycol. 5. The acid component of the crosslinked polyester resin (a) comprises 20 to 80 mol% terephthalic acid and 20 to 80 mol% isophthalic acid, and the alcohol component comprises 2 to 50 mol% glycerin and 70 to 98 mol% ethylene glycol. The method for producing a resin for toner according to claim 1, characterized by comprising: 6. A glass transition temperature of 50 ° C. or higher and a softening temperature of 20.
100 parts by weight of crosslinked polyester resin (a) having a temperature of 0 ° C. or lower,
And a softening temperature of 150 ° C or less and a weight average molecular weight of 3,000 to 5
A resin for toner comprising 0.5 to 80 parts by weight of a linear polyester resin (b) having an amount of 000. 7. The acid component of the linear polyester resin (b) is 20 to 80 mol% terephthalic acid and 20 to 80 mol% isophthalic acid.
7. The toner resin according to claim 6, wherein the diol component is ethylene glycol. 8. The acid component of the crosslinked polyester resin (a) is 2 to 30 mol% of trimellitic acid, 10 to 70 mol% of terephthalic acid and 0 to 88 mol% of isophthalic acid, based on the total acid components,
The toner resin according to claim 6, wherein the alcohol component is at least one selected from ethylene glycol and aromatic diols. 9. The acid component of the crosslinked polyester resin (a) comprises 20 to 80 mol% of terephthalic acid and 20 to 80 mol% of isophthalic acid, and the alcohol component thereof is pentaerythritol 1 to 50.
7. The toner resin according to claim 6, which comprises 70% by mole of ethylene glycol and 70-99% by mole of ethylene glycol. 10. The acid component of the crosslinked polyester resin (a) is 20 to 80 mol% of terephthalic acid and 20 to 80 mol% of isophthalic acid.
Consisting of 2 to 50 mol% of glycerin,
7. The toner resin according to claim 6, which comprises 70 to 98 mol% of ethylene glycol.