JPH059278A - Polyester resin for toner - Google Patents

Abstract

PURPOSE:To provide the title resin having good melt flow characteristics and low- temperature fixability, excellent blocking resistance, and a melt viscosity with a low temperature dependence. CONSTITUTION:The title resin which has no crosslinking structure, consists of units (a) derived from terephthalic and/or isophthalic acid component, in an amount of 40-100mol% based on the whole carboxylic acid component, units (b) derived from bisphenol diol component, in an amount of at most 80mol% based on the whole carboxylic acid component, and units (c) derived from an aliphtic diol, in an amount of at least 20mol% based on the whole carboxylic acid component, and contains the units (a) in an amount of 40-100mol% based on the all carboxylic acid component units, in which the units (c) contain alicyclic diol units and aliphatic diol units other than the alicyclic diol units, respectively, in amounts of 1-60 and 40-99mol% based on the all carboxylic acid component units, and which has a glass transition temperature Tg of 40-70 deg.C, a softening temperature of 70-130 deg.C, a weight-average molecular weight Mw of 4,000 to 16,000, a number-average molecular weight Mn of 2,000 to 8,000, a temperature T1 at which the melt viscosity is 5,000 P, of 100-145 deg.C, a temperature T2 at which the melt viscosity is 500P, of 125-175 deg.C, and a temperature difference (T2-T1) of at least 20 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin useful as a dry toner used for developing an electrostatic charge image or a magnetic latent image in electrophotography, electrostatic recording, electrostatic printing and the like. More specifically, a polyester for toner which has excellent blocking resistance, melt fluidity and low-temperature fixability, and is particularly useful for full-color toners requiring high melt fluidity, high-speed copying machines and high-speed printers requiring low-temperature fixability. Regarding resin.

[0002]

2. Description of the Related Art To obtain a permanent visible image from an electrostatic charge image,
A method is used in which an electrostatic charge image formed on a photoconductive photoreceptor or an electrostatic recording material is developed with toner charged in advance by friction and then fixed. In the case of a magnetic latent image, a method is used in which the latent image on the magnetic drum is developed with toner containing a magnetic material and then fixed. For fixing, the toner image obtained by development is directly fused on the photoconductive photoconductor or the electrostatic recording body, or the toner image is transferred onto paper or film and then fused onto the transfer sheet. Done by Toner image fusion is performed by contact with solvent vapor, pressurization and heating.There are non-contact heating method with electric oven and pressure heating method with pressure roller, but high speed fixing process is required. Recently, the latter is mainly used.

Toners used in the dry developing system include one-component toners and two-component toners. The two-component toner is prepared by first melt-kneading a resin, a colorant, a charge control agent and other necessary additives to sufficiently uniformly disperse them, then coarsely pulverizing and finely pulverizing them and classifying them into a predetermined particle size range. Manufactured. The one-component toner is manufactured in the same manner by adding magnetic iron powder in addition to the respective components of the above two-component toner.

Since the resin is the main component in the toner formulation,
It controls most of the performance required for toner. Therefore, the toner resin is required to have good dispersibility of the colorant in the melt-kneading step in the toner manufacturing step, good pulverizability in the pulverizing step, and the like. Versatile performance such as good blocking property and good electrical property is required. Epoxy resin, polyester resin, polystyrene resin, methacrylic resin, etc. are known as the resin used for the production of toner, but as the resin for the pressure-bonding heat fixing system, mainly styrene and (meth) acrylic acid ester Coalescence has been used. However, polyester resins are attracting attention because they can be fixed at lower temperatures and the fixed toner images have excellent resistance to PVC plasticizer.

Further, in order to obtain a color image, it is necessary to adhere toners of 3 to 4 colors to the transfer paper in the above-mentioned developing step, and then to develop and fix the color while melting and mixing the respective components in the fixing step. .. As described above, a resin having a good mixing property in the fixing step, that is, a resin having a good melt fluidity is strongly desired for the binder for full-color toner. When a resin binder having a good melt fluidity is used, there is a problem that an offset resistance phenomenon occurs in the fixing step. However, in order to prevent the offset phenomenon, if the binder is crosslinked or polymerized,
It is not suitable as a binder resin for full-color toners because the melt fluidity is reduced. Therefore, in the case of a full-color copying machine, silicone oil or the like is applied to the surface of the fixing roller in order to obtain offset resistance.

Recently, there has been a strong demand for speeding up of the fixing section and energy saving, and in general copying machines and printers other than full-color, a method of preventing offset such as applying silicone oil to the fixing roller has been used. There are many examples. Binder resins for full-color toners and high-speed copying machine toners must have a high Tg despite their low viscosity. There is a strong demand for the appearance of a resin having properties that are incompatible with each other in polymer design, such as high Tg, excellent blocking resistance, and low melt viscosity.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin for toner which has good melt fluidity and low-temperature fixability, is excellent in blocking resistance, and has little temperature dependence of melt viscosity.

[0008]

The toner polyester resin of the present invention comprises (a) a unit derived from a terephthalic acid component and / or an isophthalic acid component,
(B) 80% by mole or less of the following formula (1) based on all carboxylic acid components:

[0009]

[Chemical 2] In the formula, R is an alkylene group having 2 or 3 carbon atoms, and x
And y are integers, and 2 ≦ (x + y) ≦ 6.
A unit derived from a diol component represented by: and a unit derived from 20 mol or more of an aliphatic diol with respect to (c) all carboxylic acid components, and 100 mol% of the unit derived from the aliphatic diol of (b), and the unit derived from the alicyclic diol is 1 to 60 mol% with respect to the total carboxylic acid component unit.
A polyester resin having a glass transition temperature Tg of 40 to 70 ° C., which is a polyester resin containing an aliphatic diol unit other than an alicyclic diol unit in an amount of 40 to 99 mol% based on all carboxylic acid component units. The softening temperature is 70 to 130 ° C, the weight average molecular weight Mw is 4000 to 16000, and the number average molecular weight Mn is
2000-8000, the temperature T at which the melt viscosity becomes 5000 poise
₁ is 100-145 ℃, the temperature T at which the melt viscosity becomes 500 poise
₂ is 125 to 175 ° C, and the temperature difference (T ₂ −T ₁ ) is 20
It is characterized by being above ℃.

The terephthalic acid and / or isophthalic acid component referred to in the present invention means terephthalic acid, isophthalic acid or their lower alkyl esters. These aromatic dicarboxylic acid components have a glass transition temperature T of the resin.
It has the effect of increasing g and improves the blocking resistance of the toner using this. Therefore, the terephthalic acid and isophthalic acid component units are 40 to 1 with respect to the total carboxylic acid component units.
It must be contained in an amount of 00 mol%, preferably 60 to 100 mol%.

Specific examples of other dicarboxylic acid components used in addition to the terephthalic acid component and / or the isophthalic acid component, if necessary, include phthalic acid, sebacic acid, isodecyl succinic acid, maleic acid, fumaric acid, and adipine. Acids and their monomethyl, monoethyl, dimethyl, diethyl esters and the like and their acid anhydrides. Since these dicarboxylic acid components greatly affect the fixing property and blocking resistance of the toner, they can be used within the composition range described in the claims depending on the required performance of the polyester resin.

Specific examples of the diol represented by the formula (1) used in the present invention include 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)-
2,2-bis (4-hydroxyphenyl) propane and the like can be mentioned, and these diols can be used alone or in combination of two or more. Since the aromatic diol has an effect of increasing the glass transition temperature Tg, the blocking resistance is improved. In particular, polyoxypropylene (n) -2,2-bis (4-hydroxyphenyl) propane with 2.1 ≦ n ≦ 2.5 and polyoxyethylene (n) with 2.0 ≦ n ≦ 3.0. -2,2-bis (4-hydroxyphenyl) propane is preferred. Such diol component is the Tg of resin
However, the amount thereof is limited when used in combination with an aromatic dicarboxylic acid that requires a high reaction temperature, because thermal decomposition is likely to occur at high temperatures. The amount of diol component units is 80 based on the total carboxylic acid component units.
It should be not more than mol%. It is preferably 70 mol% or less.

Specific examples of the aliphatic diol used in the present invention include ethylene glycol, neopentyl glycol, propylene glycol, butanediol, polyethylene glycol and the like. These aliphatic diols may be used alone or in combination of two or more. used. These aliphatic diols have a function of improving the polycondensation reaction rate. Among these, ethylene glycol, neopentyl glycol and butanediol are preferable from the viewpoint of fixing property. The amount of the aliphatic diol units is 20 mol% or more, preferably 30 mol% or more, based on the total carboxylic acid component units.

The aliphatic diol used in the present invention contains an alicyclic diol as a part thereof. Specific examples of the alicyclic diol include 1,4-cyclohexanediol, hydrogenated bisphenol A, 1,4-cyclohexanedimethanol, polyoxypropylene-2,2-bis (4-hydroxycyclohexyl) propane, polyoxyethylene. −
2,2-bis (4-hydroxycyclohexyl) propane, hydrogenated bisphenol S, hydrogenated bisphenol F,
1,4-bis (1-hydroxyethyl) cyclohexane, polyoxyethylene-1,4-cyclohexanediol, polyoxypropylene-1,4-cyclohexanediol, 4,4′-biscyclohexanediol and the like can be mentioned. The components are effective for improving the glass transition temperature Tg, lowering the softening temperature, and improving wear resistance. The amount of all such alicyclic diol units is 1 to 60 mol%, preferably 5 to 50 mol%, based on the carboxylic acid component units. If the amount of the alicyclic diol unit is less than 1 mol%, the effect expected in the present invention cannot be obtained, and if it exceeds 60 mol%, the reaction may slow down.

Generally, a monomer other than the above may be used within the range of 10 mol% or less based on the total amount of the polyester, as long as the characteristics of the polyester are not impaired.
The most important point in the present invention is that the polyester resin has a glass transition temperature Tg of 40 to 70 ° C. and a softening temperature of 70.
At ~ 130 ° C, the weight average molecular weight Mw is 4000 to 16000, the number average molecular weight Mn is 2000 to 8000, and the melt viscosity is
The temperature T ₁ to reach 5000 poise is 100 to 145 ° C, and the melt viscosity is
The temperature T _{2 at} which it becomes 500 poise is 125 to 175 ° C., and the temperature difference (T ₂ −T ₁ ) is 20 ° C. or more.

When an inorganic powder such as silica is added to the polyester resin, the blocking resistance becomes good, and the effect is more remarkable as the Tg is lower. However, Tg
For resins below 40 ° C, blocking resistance will not be good even if inorganic powder is added. Resins having a Tg of 50 ° C or higher have good blocking resistance without adding inorganic powder. On the other hand, if Tg exceeds 70 ° C., the softening temperature becomes high and the melt fluidity decreases, so that it is not suitable for full-color toners and high-speed printer toners. Therefore, Tg is 70
It must be below ℃. Therefore, Tg is 40-70
The temperature must be 0 ° C, preferably 50 to 70 ° C.

When the softening temperature of the polyester resin is less than 70 ° C., melt fluidity and low temperature fixability are improved, but T
g is lowered, and blocking resistance is significantly lowered. If the softening temperature exceeds 130 ° C, the melt fluidity and low-temperature fixability will deteriorate, so it is not suitable for high-speed copying machines for full-color toner and fixability. Therefore, the softening temperature is 70-130.
℃.

If the weight average molecular weight Mw is less than 4000, T
g is remarkably reduced and blocking resistance is deteriorated. If the weight average molecular weight Mw exceeds 16000, the melt fluidity and low-temperature fixability deteriorate, which is not suitable for full-color toners and high-speed copying machines. The same applies to the number average molecular weight Mn. That is, when the number average molecular weight Mn is less than 2000, Tg is remarkably lowered and the blocking resistance is deteriorated. If the number average molecular weight Mn exceeds 8,000, the melt fluidity and low-temperature fixability will be deteriorated, making it unsuitable for full-color toners and high-speed copying machines. Therefore, the weight average molecular weight Mw
Should be 4000 to 16000 and the number average molecular weight Mn should be 2000 to 8000.

The temperature T _{1 at} which the melt viscosity reaches 5000 poise is 1
If it is less than 00 ° C, Tg is remarkably lowered and the blocking resistance is deteriorated. If the temperature T _{1 at} which the melt viscosity reaches 5000 poise exceeds 145 ° C., the melt fluidity and low-temperature fixability deteriorate, making it unsuitable for full-color toners and high-speed copying machines. Therefore, the temperature T ₁ that reaches 5000 poise is 100-
Must be 145 ° C.

Furthermore, the temperature T at which the melt viscosity reaches 500 poises
_{When 2} is less than 125 ° C., Tg is remarkably lowered and blocking resistance is deteriorated. If the temperature T _{2 at} which the melt viscosity reaches 500 poise exceeds 175 ° C., the melt fluidity and low-temperature fixability deteriorate, making it unsuitable for full-color toners and high-speed copying machines. Therefore, the temperature T _{2 to} reach 500 poise is
Must be 125-175 ° C.

A state where the melt viscosity is around 5000 to 500 poise
Is the viscosity to be melt-kneaded during the production of polyester resin toner.
Yes, even when used as toner, it was fixed on paper
As a full color, it is possible to melt mix multiple colors
Since this is also this viscosity range, it is an important viscosity range. 5000
If the temperature dependence of the melt viscosity in the vicinity of ~ 500 poise is high,
Toner characteristics change depending on slight temperature changes during toner manufacturing
Also inside or outside the copier when used as a toner
Depending on the temperature environment of the
Even if it is used as a product, it will change the melt-mixed state and cause uneven coloring.
It Therefore, the temperature T to reach 5000 poise ₁And 500 poise
Temperature T₂Difference of (T₂-T₁) Requires 20 ° C or higher
It

In the present invention, “softening temperature” means 1 mmφ × using a flow tester CFT-500 manufactured by Shimadzu Corporation.
It is the temperature at which 1/2 of 1.0 g of the sample flows out when measured under a 10 mm nozzle, a load of 30 Kf, and a constant heating rate of 3 ° C./min. Further, the viscosities of 5000 poise and 500 poise were measured by using the same model under a constant rate of temperature rise of 0.5 mmφ × 15 mm nozzle, 10 kg load, and 3 ° C./min temperature rise rate, and calculated from the temperature viscosity curve.

The glass transition temperature Tg is the temperature at the intersection of the tangent to the base line of the chart and the tangent of the endothermic curve near Tg when measured at a temperature rising rate of 5 ° C./min using a differential scanning calorimeter. The weight average molecular weight Mw and the number average molecular weight Mn were measured by GPC HCL-8200 manufactured by Tosoh Corporation.

[0024]

EXAMPLES Examples of the present invention will be shown below, but the embodiments of the present invention are not limited thereto. Example 1 Monomers were charged into a reaction vessel according to the composition shown in Table-1. However, due to the reaction, the composition shown in Table 1 is 40% with respect to all acid components.
An excess of mol% ethylene glycol was added. Furthermore, the polymerization catalyst, antimony trioxide, was added to the acid component at 40%.
0 ppm was added. Next, the internal temperature is 230 ° C and the stirring speed is 200 rpm.
And the esterification reaction was carried out under normal pressure for 5 hours. Then, the internal temperature was kept at 240 ° C and the stirring speed was 200 rpm, and the degree of vacuum was
The pressure was gradually reduced over 40 minutes until the pressure reached 1.0 mmHg. The end point of the reaction was when the softening temperature was traced and the desired softening temperature was reached.

Light yellow resins R-1 to R-5 were obtained. The physical properties of those resins are shown in Table 1. From Table-1, resin R-
1 to R-5 have a low softening temperature and a low molecular weight and a high Tg, so that they have good melt fluidity and good blocking resistance, and have a temperature T _{1 of} 5000 poise and a temperature T of 500 poise. _It can be seen from the difference between ₂ that the melt fluidity has little temperature dependence, the color unevenness is small for full-color toners depending on the environment, and the melt-kneading step during toner production is stable.

[0026]

[Table 1] Example 2 According to the composition of Table 2, the same operations as in Example 1 were carried out except that a monomer was charged in a reaction vessel, and resins R-6 to R-10 were used.
Got Table 2 shows the physical properties of the resins R-6 to R-10.
As shown in Table-2, the resins R-6 to R-10 have a low softening temperature and a low molecular weight and a high Tg, and thus have a good melt fluidity and a good blocking resistance, as in Example-1. Since there is a difference between the temperature T _{1 at} which it becomes 5000 poise and the temperature T _{2 at} which it becomes 500 poise, there is little temperature dependence of the melt flowability, and there is little color unevenness for full-color toners depending on the environment. It can be seen that the melt-kneading process is also stable.

[0027]

[Table 2] Comparative Example 1 Resins R-11 to R-R were prepared in the same manner as in Example 1, except that the monomers were charged in the reaction vessel according to the composition shown in Table 3.
I got -15. Table 3 shows the physical properties of the resins R-11 to R-15.

From Table 3, since the resin R-11 contains 90 mol% of the aromatic diol in the acid component, the reactivity is low and the molecular weight does not increase. Therefore, Tg also does not rise. Since the resin R-12 does not use an alicyclic diol, when the molecular weight Mw is set to about 4000, Tg decreases to 38 ° C,
Blocking resistance becomes poor. When the molecular weight of resin R-13 is as high as 57,000, Tg increases to 72 ° C and the blocking resistance is extremely good, but the softening temperature is 188 ° C.
The temperature rises to 5000 poise and 500 poise, and the temperature is 200 ℃
Melt flowability is deteriorated, and it is not suitable for high-speed copying machines for full-color and fixing.

Resin R-14 has a low softening temperature and a Tg of 50.
Since it is ℃, it seems to be suitable for high-speed copiers for full-color and low-temperature fixability, but since the difference between the temperature T _{1 at} which it becomes 5000 poise and the temperature T ₂ at which it becomes 500 poise is small, it is a full-color toner. When used as an application, the melt fluidity changes due to changes in the temperature environment in the copying machine, which causes color unevenness.

Since the resin R-15 has a molecular weight of less than 4000, its Tg is extremely low and its melt flowability is good, but its blocking resistance is poor.

[0031]

[Table 3] Comparative Example 2 Resins R-16 and R-17 were obtained in the same manner as in Example 1 except that monomers were charged according to the composition shown in Table 4.
The physical properties of the resins R-16 and 17 are shown in Table-4. As shown in Table 4, since resin R-16 uses a large amount of hydrogenated bisphenol A, the molecular weight does not increase even after reacting for 10 hours, melt flowability is good, but Tg does not increase and blocking resistance is poor. Is.

Since the resin R-17 has a softening temperature of 103 ° C., it has good low-temperature fixability and melt flowability, and its melt viscosity has little temperature dependence, but its Tg is as low as 38 ° C. Becomes defective.

[0033]

[Table 4]

[0034]

The dry toner prepared from the polyester resin of the present invention has good melt fluidity and low-temperature fixability, excellent blocking resistance, and low temperature dependence of melt viscosity. Therefore, this toner is useful for full-color, which requires particularly high melt fluidity, for high-speed copying machines and high-speed printers, which require low-temperature fixability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location G03G 9/087 (72) Inventor Masayuki Takyu 2 Sanbishi, 4-1, Ushikawa-dori, Toyohashi City, Aichi Prefecture Rayon Co., Ltd. Toyohashi Plant (72) Inventor Masahiro Ito 4-1-1 Sunadabashi, Higashi-ku, Nagoya, Aichi Prefecture Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Koichi Ito 4-chome, Sunadabashi, Higashi-ku, Nagoya, Aichi Prefecture Address 60 Mitsubishi Rayon Co., Ltd. Product Development Laboratory

Claims (1)

Claims: (a) A unit derived from a terephthalic acid component and / or an isophthalic acid component; and (b) 80 mol% or less of the following formula (1) based on the total carboxylic acid component: Chemical 1] In the formula, R is an alkylene group having 2 or 3 carbon atoms, and x
And y are integers, and 2 ≦ (x + y) ≦ 6. A unit derived from a diol component represented by: and a unit derived from 20 mol or more of an aliphatic diol with respect to (c) all carboxylic acid components, and 100 mol% of the unit derived from the aliphatic diol of (c), and the unit derived from the alicyclic diol is 1 to 60 mol% with respect to the total carboxylic acid component unit.
A polyester resin having a glass transition temperature Tg of 40 to 70 ° C., which is a polyester resin containing an aliphatic diol unit other than an alicyclic diol unit in an amount of 40 to 99 mol% based on all carboxylic acid component units. The softening temperature is 70 to 130 ° C, the weight average molecular weight Mw is 4000 to 16000, and the number average molecular weight Mn is
2000-8000, the temperature T at which the melt viscosity becomes 5000 poise
₁ is 100-145 ℃, the temperature T at which the melt viscosity becomes 500 poise
₂ is 125 to 175 ° C, and the temperature difference (T ₂ −T ₁ ) is 20
A polyester resin for toner, which has a temperature of ℃ or higher.