JPS6245622A - Polyester resin for toner - Google Patents

Abstract

PURPOSE:The titled resin which can give a toner wide in a range of non-offset fixation temperature and excellent in blocking resistance, containing a non volatile monocarboxylic acid component and specified in a glass transition temperature and a softening temperature range. CONSTITUTION:The following components A, B, C and D are weighed out so that the amounts of components C and D are determined on the basis of the amounts of components A and B according to the relationships I and II wherein (a) is the amount (mol) of (a) dicarboxylic acid (A), (e.g., terephthalic acid), (b) is the amount of a diol (B) (e.g., ethylene glycol), c1 mol of an at least tribasic polycarboxylic acid [e.g., trimellitic acid (anhydride)] and/or c2 mol of at least trihydric polyalcohol (e.g., sorbitol) and (d) mol of a nonvolatile monocarboxylic acid (D) (e.g., monosodium sulfobenzoate). Components A, B and C are polycondensed together at 130-300 deg.C in a N2 stream, for example. After adding component D to the reaction system, the whole is further polycondensed while the degree of crosslinking is controlled suitably so that the softening temperature of the resin may be 90-170 deg.C. In this way, the titled resin of a glass transition temperature >=50 deg.C is obtained in good reproducibility.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyester resin for toner used for development in electrophotography, electrostatic recording, etc.

[Conventional technology]

As a conventional electrophotographic method, U.S. Patent No. 2,297,69
No. 1, No. 2,357,809, etc., a photoconductive layer is uniformly charged, and then this layer is exposed to light fC, and the electric charge is dissipated in the exposed portion. After fully forming a latent image, toner gold is attached to this latent image to make it visible (development process), and the resulting visible image is transferred to a transfer material such as transfer paper (transfer process), heat and pressure are applied. Alternatively, it consists of a step of permanently fixing (fixing step) by another suitable fixing method. As described above, the toner must have the performance required not only in the development process but also in each of the transfer and fixing processes.

Generally, toner is subjected to mechanical frictional force due to shearing force and impact force during mechanical operation in a developing device, and deteriorates while copying thousands to tens of thousands of copies.

To prevent such toner deterioration, it is possible to use a strong resin with a large molecular weight that can withstand mechanical friction, but such resins have a high softening temperature, resulting in a high fixing temperature and non-contact fixing. However, even in the heat roller fixed fixing method, which is a contact fixing method and has good thermal efficiency, it is necessary to raise the temperature of the heat roller in order to achieve sufficient fixing. Therefore, it is not a problem that causes problems such as deterioration of the fixing device, curling of paper, and increased energy consumption, but also reasons such as difficulty in pulverizing toner when manufacturing toner, and difficulty in uniformly dispersing the colorant. Otherwise, manufacturing efficiency will be significantly reduced.

For this reason, those having a high degree of polymerization and even a high softening temperature are not suitable for use as a binder resin.

Furthermore, in the heat roller constant fixing method, the heating roller surface and the toner image surface of the fixing sheet come into pressure contact, so the thermal efficiency is extremely high, and it is widely used from low speeds to high speeds. When the image surfaces come into contact, a so-called offset phenomenon tends to occur, in which toner adheres to the surface of the heating roller and is transferred to a subsequent transfer paper or the like. In order to prevent this phenomenon, the surface of the heating roller is coated with a material with excellent mold release properties such as fluororesin, and the surface of the heating roller is coated with a mold release agent such as 1) corn oil to completely eliminate the offset phenomenon. It is prevented. However, the method of applying silicone oil or the like is undesirable because the fixing device is unstable and the cost is high, and it also becomes complicated and tends to cause trouble. Therefore, in order to prevent the offset phenomenon, various improvements have been made not only to the fixing device but also toner.

As described in Japanese Patent Publication No. 55-6895 and Japanese Patent Application Laid-open No. 56-98202, there is a method to improve the υ offset phenomenon by widening the molecular weight distribution of the binder resin, but this increases the degree of polymerization of the resin. Therefore, it is necessary to increase the fixing temperature.

As a further improved method, as described in Japanese Patent Publication No. 57-493, Japanese Patent Application Publication No. 50-44836, and Japanese Patent Application Publication No. 57-37353, the off-set phenomenon is improved by making the resin asymmetrical and crosslinking. Although there is a method to do this, there is no improvement in terms of lowering the fixing temperature.

In general, if the fusing temperature can be lowered without lowering the offset generation temperature, the usable temperature range can be expanded, and there are many advantages such as energy saving, faster fusing, and relaxing the tolerance range of accuracy for temperature control of the fusing device. be.

Therefore, resins and toners with good fixing properties and offset resistance are always desired.

For styrene resin, JP-A-49-65232, JP-A-50-28840, JP-A-50-81342
As described in the above publication, it is known that offset resistance can be improved by incorporating a small amount of low molecular weight polymers, fatty acid esters, polyamide wax, paraffin wax, etc. into the toner composition. However, styrene resins inherently have a high minimum fixing temperature, and there are limits to the improvement of the resin composition and the addition of waxes.

On the other hand, since polyester resin inherently has good adhesiveness and fixing properties, it can be sufficiently fixed even in a non-contact fixing method, as described in, for example, US Pat. No. 3,590,000. Furthermore, as described in Japanese Patent Application Laid-Open No. 57-37353, there is also known a polyester resin which can be fixed without causing any offset by using a polyhydric caldic acid or by a fixed fixing method using a heat roller. However, in order to improve the offset phenomenon, polyester resin is made non-linear and has a high molecular weight using polyhydric caldic acid, but the low-temperature fixing properties originally possessed by polyester resin are sacrificed. However, the pulverizability of the toner decreases.

Therefore, the present inventors conducted intensive studies to find a resin for toner that can further improve the excellent properties of these polyester resins, and as a result, they discovered a polyester resin that has excellent low-temperature fixing properties and anti-offset properties, and arrived at the present invention. did.

[Problems to be solved by the invention]

The present invention has been made to provide a polyester resin for toner which can solve all of the conventional problems, have a low fixing temperature and a high offset generation temperature, and therefore can have a wide non-offset fixing temperature range.

Another object of the present invention is to provide a polyester resin for toner that has excellent anti-blocking properties.

[Means for Solving All Problems] That is, the polyester resin for toner provided by the present invention is a polyester resin having a nonvolatile monocarginic acid component tt, and has a glass transition temperature of 50° C. or higher and is soft. It is characterized by a temperature of 90 to 170°C.

[Detailed description and examples of the invention]

The polyester resin for toner of the present invention is made of Zocal®, which is a common component of polyester resin. One of its characteristics is that it contains a non-volatile monocarboxylic acid component, gold, in addition to the acid component and diol component. Here, the monocardic acid component being nonvolatile means that it does not substantially volatilize at the polycondensation temperature. By containing such non-volatile components, the degree of crosslinking during polycondensation can be well controlled, and polyester resins can be stably produced with good reproducibility.

The glass transition temperature of the polyester resin for toner of the present invention needs to be 50° C. or higher in order to make the polyester resin for toner excellent in blocking resistance. If the temperature is less than 50°C, it is not preferable because, for example, the resin cannot be smoothly supplied to the melting mixer during toner production, and clogging may occur in the copying machine.

Moreover, the softening temperature needs to be 90 to 170°C. 9
If it is less than 0°C, the temperature at which offset occurs will be extremely low, and the temperature range in which fixing is possible will be narrow; if it exceeds 170°C, it will be necessary to fix at a high temperature, making it extremely difficult to increase the speed of the copying machine.

As described above, the present invention exhibits outstanding characteristics not seen before as a toner resin by containing gold as a nonvolatile monocarboxylic acid component and by setting the glass transition temperature and softening temperature within specific ranges. ), as will be explained in detail in Examples below, it is possible to lower the fixing temperature, increase the offset generation temperature, widen the non-offset fixing temperature range, and exhibit all the characteristics of excellent blocking resistance.

The 4-lyester resin for toner of the present invention is preferably manufactured or constituted by, for example, a combination of the following components.

A) dicarboxylic acid (hereinafter referred to as component A), B) di-
1L/(hereinafter referred to as B component), C) trivalent or higher polyvalent caldic acid (hereinafter referred to as Ct acid component), or/and 3
polyhydric alcohol (hereinafter referred to as C1 component), D) non-volatile monocarbon [(hereinafter referred to as D component)
.

In addition, the amounts of C, C, and D components (01 mol and b mol, respectively) for A and B components (1 mol and b mol, respectively)
mol, 02 mol, and d mol) can be arbitrarily determined as appropriate, but each is more preferably as follows.

Examples of dicarboxylic acids as component A used in the present invention include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glumeconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, and cono-phosphoric acid. , adipic acid, sebacic acid, malonic acid,
Examples include naphthalene-carboxylic acid, anhydrides thereof, dual bodies of lower alkyl esters and lyluic acid, and other divalent organic acids.

The diol of component B used in the present invention is as follows:
For example, diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1.2-f-ropylene glycol, 1.3-7'-ropylene glycol, 1,4-butadiol, neopentyl glycol, 1,4-butynediol, 1. 4-bis(hydroxymethy/L
/) Cyclohex f7, and bisphenol A, hydrogenated bisphere #man.

Etherified bisphenols such as polyoxyethylenated bisphenol A, and lyoxyzolopyrenated bisphenol A, and other divalent alcohol monomer gold can be mentioned.

In addition, as the C1 component trivalent or higher polycarboxylic acid, trimellitic acid, trimesic acid, pyromellitic acid, 1.2
．． 4-cyclohexanetricardanoic acid, 2.5.7-naphthalendolicarzenic acid, 1.2.4-naphthalenetricardonic acid? acid, 1.2.4-butanetricardonic acid, 1,
2.5-hexanetricarbic acid, 1゜3-dicargoxyl-2-methyl-2-methylenecarboxypropane,
Tetra(methylenecartoxyl)methane, 1.2,7.
8-octane tetracaldic acid, embol trimer acid,
and acid anhydrides thereof, and others.

In addition, examples of the C3 component trihydric or higher polyhydric alcohol include sorbitol, 1.2.3.6-hexanetetrol, 1.4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3
．． 5-) rihydroxymethylbenzene, and other gold.

Examples of the nonvolatile monocarboxylic acid as component D used in the present invention include sulfobenzoic acid monoammonyl salt, sulfobenzoic acid monosodium salt, and cyclohexylaminocarboxylic acid. n-dodecylaminocargenylbenzoic acid, and all others.

Each of the seven components of these A, B, cl, C, and D components
Each of these can be used alone or in combination of two or more.

The polyester resin for toner of the present invention includes, for example, the above-mentioned A,
It can be produced by polymerizing monomer gold of components B, C, and D. At this time, each component can be present as a component of the monomer mixture at the beginning of the polymerization, or can be added to the reaction mixture after the polymerization has started. Specifically, for example, components A, B, and C are polycondensed at 130 to 300°C under a nitrogen stream, then component D is added, and the resin is further polycondensed so that the softening temperature of the resin is 90 to 170°C. Condensation method: After transesterifying the dicarginic acid ester of component A with components B and C at 't160 to 180'C, polycondensation is performed at 260 to 300 tl:, then adding component D, Furthermore, the softening temperature of the resin is 90~
Examples include a method of polycondensing at 170°C. In the above method, component C can also be added after the polycondensation of components A and B has started, before all of component D has been added.

At this time, when an acid anhydride is used as component A, the reaction temperature for polycondensation is 100 to 250°C, preferably 130 to 250°C.
180℃, Dical? The reaction temperature when using phosphoric acid is 15
The temperature is preferably 0 to 300C1, preferably 180 to 260C. Is it dical of the 7hA component? When using a method of transesterifying the phosphoric acid ester, followed by polycondensation, it is necessary to carry out the transesterification sufficiently. If the transesterification is insufficient, the glass transition temperature may not reach 50° C. or higher even if the softening temperature reaches a predetermined temperature.

In addition, non-volatile monocarginic acid, which is component D, is used during polymerization when the polymerization reaction rate of the reaction mixture consisting of A, B% C1 and C2 becomes 50 or more, and furthermore 80 or more. is preferable.

This is because if the polymerization reaction rate is less than 50%, the desired performance may not be obtained at the softening temperature or glass transition temperature of the resin.

In the polymerization, di-n-butyltin oxide, zinc acetate, cobalt acetate, magnesium acetate, manganese(II) acetate, calcium acetate, antimony dioxide, tetra-n-butoxytitanium, etc. can be used as a catalyst. can.

The thus obtained polyester resin for toner of the present invention is used as a toner after being cross-dispersed with a colorant and an auxiliary agent, and then subjected to pulverization, granulation, surface treatment and classification, and then pulverized to a fine powder. Caden black is most widely used as a colorant, and in the case of magnetic toners, iron oxide-based black magnetic powder is often used. Specific examples of auxiliary agents include charge control agents, fluidity improvers, and adhesion improvers, all of which may be added in small amounts. The toner prepared in this manner can be used as a developer in a fixing device such as the heat roller constant fixing method as described above.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

Note that the glass transition temperature and softening temperature as used in the present invention refer to those measured as follows.

〔Glass-transition temperature〕

Differential scanning thermal anonymizer (Seiko Electronics Department SSC-580 model)
The value measured once again after rapidly cooling the sample.

[Softening temperature]

Rod outflow temperature measured with a flow tester (Shimadzu CFT-500 model) (nozzle 1wφXIO■, load 3
9f at 0', heating rate 3°C/mtn).

[Example 1] Dimethyl terephthalate 801! , dimethyl isophthalate 12011. and 130 g of ethylene glycol.
Pour into a round bottom flask. The mixture is melted in a heating bath while nitrogen gas is introduced through a glass introduction tube, and 0.31 i of tetra-n-butoxytitanium is added thereto, followed by reaction at 180° C. for 90 minutes with stirring.

After raising the temperature to 280°C and reacting for 150 minutes, 20.9 t of anhydrous trimeri was added and the reaction was continued for 30 minutes.
-Sulfobenzoic acid monosodium salt 81 was added and reacted for further 60 minutes to obtain a resin having a glass transition temperature of 52°C and a softening temperature of 114°C.

[Example 2] Isophthalic acid 91. ! 9. ) Liethylene glycol 15
0II, and trimellitic anhydride 63. fi'e As in Example 1, it is placed in a reaction vessel and an inert atmosphere is created. Then, melt in a heating bath and add 0.05% dibutyltin oxide. f'f
After adding fi and reacting at 200°C for 3 hours with stirring, cyclohexylaminocal? Nilbenzoin @27! In addition, the reaction was further continued for 3 hours to obtain a resin having a glass transition temperature of 56°C and a softening temperature of 99°C.

[Example 3] 160 g of dimethyl terephthalate, 40 g of dimethyl isophthalate, Bispheno-/I/A114.9. Ethylene glycol 311 and glycerin 301 were placed in a reaction vessel in the same manner as in Example 1 to create an inert atmosphere. Next, the mixture is melted in a heating bath, 0.3 g of calcium acetate and 0.1 gi of antimony trioxide are added, and the mixture is reacted at 180° C. for 90 minutes with stirring. After raising the temperature to 280°C and reacting for 2 hours, 10gk of m-sulfobenzoyane monoammonium salt was added, and
The reaction was continued for hours to obtain a resin with a glass transition temperature of 63°C and a softening temperature of 123°C.

[Example 4] Fumaric acid 261, succinic anhydride 518.9% polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane 200 g, and pyromellitic acid 45
．． fi is placed in a reaction vessel and an inert atmosphere is created in the same manner as in Example 1. Then, by melting in a heating bath, ・Sibutyltin oxide 0
．． After adding 05#i and reacting at 200°C for 3 hours with stirring, n-dodecylaminocarmenylbenzoic acid 41ii was added and reacted for further 4 hours to obtain a resin gold with a glass transition temperature of 58°C and a softening temperature of 166°C. Ta.

[Comparative Example 1] 80 fI of dimethyl terephthalate, 120 F of dimethyl isophthalate, and 130 yt of ethylene glycol - placed in a reaction vessel in the same manner as in Example 1 to create an inert atmosphere. Next, 0.3 I of calcium acetate and 0.1 g-i of antimony trioxide were added to the melted mixture in a heating bath, and the mixture was heated at 180°C under stirring for 90°C.
Let it react for a minute. After raising the temperature to 280°C and reacting for 120 minutes, 409 t of trimethylolpropane was added and 18
After 0 minutes of reaction, the glass transition temperature was 46℃ and the softening temperature was 1.
Obtain resin at 39°C fc.

[Comparative Example 2] Dimethyl terephthalate 100. F. Dimethyl isophthalate 1001 and ethylene glycol 1301t - placed in a reaction vessel as in Example 1 and provided with an inert atmosphere.

Then, by melting in a heating bath, 0.39 of calcium acetate and 0.11 of antimony trioxide were added. i and stirred at 180℃ for 90 minutes.
Let it react for a minute. After raising the temperature to 280°C and reacting for 150 minutes, 10 Jt of glycerin was added, and after reacting for 30 minutes, 20. ? Add m-sulfobenzoic acid monosodium salt of
and Resin 2 with a softening temperature of 86°C [Comparative Example 3] Isophthalic acid 911i,) Liethylene glycol 150
1i' and 11,186 g of trimesine were placed in a reaction vessel in the same manner as in Example 1 to create an inert atmosphere.

Next, the mixture was melted in a heating bath, 0.059 g of sibutyltin oxide was added, and the mixture was reacted with stirring at 200°C for 4 hours to obtain a resin having a glass transition temperature of 57°C and a softening temperature of 193°C.

The fixing properties and blocking resistance of the thus obtained friend polyester resin were evaluated, and results are shown in Results 11.

In addition, the fixing performance was evaluated by heating a Teflon-coated iron plate with a temperature gradient, placing resin powder on top of it, placing copy paper on top of it, applying moderate pressure, and then placing the copy paper on top of it. After peeling off, the lowest iron plate temperature in the area where the resin adheres only to the copy paper is measured using a contact thermometer and used as the fixing start temperature, and the lowest iron plate temperature in the area where the resin adheres to both the copy paper and the iron plate is determined as the total contact temperature. The offset generation temperature was measured using a thermometer.

The blocking resistance was evaluated by setting the resin at 20 N't at 50° C. and leaving it in a constant temperature bath for 24 hours, and then letting it cool at room temperature and determining the degree of lumpiness.

The above results are shown in Table 1. As is clear from Table 1, the samples of Examples 1 to 4, which are resins according to the present invention, all have high offset generation temperatures and low fixing start temperatures, and therefore have a wide and appropriately high fixable temperature range. It had a It also had excellent blocking resistance.

On the other hand, the sample of Comparative Example 3, which is made of polyester resin but has a high softening temperature, has a narrow and high fixable temperature range, and has poor fixability. Also, Comparative Example 2 with a low softening temperature
This sample has an extremely low offset generation temperature and cannot be fixed in practice. Friend, the sample of Comparative Example 1, which has a low glass transition temperature, is extremely susceptible to block blowing. [Effects of the Invention] According to the polyester resin for toner of the present invention, the fixing temperature is lowered and the offset generation temperature is increased. It is possible,
Furthermore, a toner with excellent blocking resistance can be obtained.

Claims (1)

[Claims] A polyester resin for a toner, which is a polyester resin containing a nonvolatile monocarboxylic acid component, having a glass transition temperature of 50°C or higher and a softening temperature of 90 to 170°C.