JP2715311B2 - Polyester resin for electrophotographic toner, method for producing polyester resin for electrophotographic toner, and toner for electrophotography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention extends from a monocolor copying machine to a full-color copying machine for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like. And a toner resin.

[Prior Art] Conventionally, many electrophotographic methods have been known as described in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-24748. However, in general, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is developed using toner, and if necessary, a transfer material such as paper is used. After the transfer of the toner image to the toner image, the toner image is fixed by heating, pressure or solvent vapor to obtain a copy.

Various methods and apparatuses have been developed for the final step of fixing the toner image on a sheet such as paper. Currently, the most common method is a pressure heating method using a heating roller.

In the pressure heating method using a heating roller, fixing is performed by allowing the toner image surface of a sheet to be fixed to pass through the surface of a heating roller having a surface formed of a material having releasability with respect to toner while contacting the surface under pressure. . In this method, since the surface of the pressure roller and the toner image of the sheet to be fixed come into contact with each other under pressure, the thermal efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. And is very effective in high speed electrophotographic copiers. However, in the above method, since the surface of the heating roller and the toner image come into contact with each other under pressure in a molten state, a part of the toner image adheres and transfers to the surface of the fixing roller, and the toner image re-transfers to the next sheet to be fixed. A so-called offset phenomenon occurs, and the sheet to be fixed may be stained. Preventing toner from adhering to the surface of the heat fixing roller is one of the essential conditions of the heat roller fixing method.

That is, at present, it is desired to develop a binder resin for a toner having a wide fixing temperature range and a high offset resistance.

Also, studies and practical applications of two-color copying machines and full-color copying machines have been greatly increased. For example, "Journal of the Institute of Electrophotography" Vo122.No1 (1983) and "Journal of the Society of Electrophotography" Vo125.N
There is also a report on color reproducibility and gradation reproducibility as in o1.P52 (1986).

However, full color electrophotographic images that are currently in practical use are not necessarily directly compared with the real ones such as televisions, photographs, and color prints, and for those who see color images that are more beautifully processed than the real ones. It is not satisfactory.

In full-color electrophotography, multiple developments are performed, and several types of toner layers of different colors are required to be superimposed on the same support. Includes the following items.

(1) In order that the fixed toner does not diffusely reflect light and hinder color reproduction, the toner needs to be in a state of almost complete melting such that the shape of the toner particles cannot be determined.

(2) It must be a binder resin having transparency that does not interfere with the toner layers of different colors under the toner layer.

In this way, for monocolor copying machines, development of a binder resin for toner with a wide fixing temperature range and high offset resistance is desired. For full-color copying machines, not only the fixing temperature range is wide but also the transparency of the resin It is required that the fixing surface be flat when fixed.

Conventionally, for the purpose of widening the fixing temperature range of the polyester resin, JP-A-57-208559, JP-A-58-11954 and JP-A-59-228661 use an offset preventing agent. In the two-component system, the spent of the carrier is promoted, and the transparency of the toner is lost for the full color use.

JP-B-59-11902, JP-A-60-214368 and JP-A-59-7960 disclose the use of aromatic polycarboxylic acids. Therefore, the smoothness of the fixing surface of the toner is impaired, and the color mixing property for full color is poor.

JP-A-58-21160, JP-A-59-9969, and JP-A-59-29255 to 59-29260 make a crosslinked polyester by using a trivalent or higher polycarboxylic acid or polyol. Further, a method of cross-linking using a polyvalent metal compound is disclosed. However, even with these methods, the elasticity becomes too large, so that the smoothness of the fixing surface of the toner is impaired, and the color mixing property for full color is poor. .

That is, it is extremely difficult to simultaneously expand the fixing temperature range and simultaneously satisfy the toner characteristics of fluidity, durability, transparency, and smoothness of the fixing surface.

[Problems to be Solved by the Invention] An object of the present invention is to provide a novel resin for an electrostatic image developing toner, which solves these problems, a method for producing the same, and a toner.

That is, an object of the present invention is to provide a resin for a heat roller fixing toner having good fixability and particularly good offset resistance, a method for producing the same, and a toner.

It is a further object of the present invention to provide a resin for a heat roller fixing toner which has excellent fluidity, does not cause aggregation, and has excellent impact resistance, a method for producing the same, and a toner.

It is a further object of the present invention to provide a heat roller fixing toner resin having good chargeability and exhibiting stable chargeability during use, and providing a clear and fog-free image, a method for producing the same, and a toner. is there.

Further, an object of the present invention is that when used as a resin for a full-color toner, the fixed toner can form a smooth fixing surface so as not to irregularly reflect light and hinder color reproduction. An object of the present invention is to provide a heat roller fixing resin, a method for producing the same, and a toner.

It is a further object of the present invention to provide a resin having transparency which does not hinder a toner layer of a different color under the toner layer when used as a resin for a full-color toner, a method for producing the same, and a toner.

[Means and Actions for Solving the Problems] The present invention is a polyester resin synthesized using at least a polyhydric alcohol component, a polyvalent carboxylic acid component and a silane coupling agent, wherein the polyester resin is
The present invention relates to a polyester resin for an electrophotographic toner, which has a three-dimensional structure having a bond with a Si metal in a crosslinking reaction by the silane coupling agent.

Further, at the time of the synthesis of the polyester resin from at least a polyhydric alcohol component and a polycarboxylic acid component, by performing a cross-linking reaction using a silane coupling agent, Si
The present invention relates to a method for producing a polyester resin for an electrophotographic toner, which comprises obtaining a polyester resin having a three-dimensional structure by bonding to a metal.

Further, in an electrophotographic toner containing at least a colorant and a polyester resin, the polyester resin is crosslinked using a silane coupling agent at the time of synthesis of the polyester resin from at least a polyhydric alcohol component and a polycarboxylic acid component. The present invention relates to a toner for electrophotography, which has a three-dimensional structure having a bond with Si metal by reacting.

When an aromatic trivalent or higher polycarboxylic acid and / or polyol conventionally used for crosslinking a polyester resin is used, the elasticity of the resin is increased, and the smoothness of the toner fixing surface is impaired for full color use. .

JP-A-59-9669 and JP-A-59-29255 to 59-29260 disclose a method of crosslinking with a polyvalent metal. However, after synthesizing a polyester, a polyvalent metal compound is added, and a mechanochemical compound is added. A method of crosslinking by a method is used. In the method of cross-linking after synthesizing polyester,
It is very difficult to uniformly disperse the polyvalent metal microscopically. Therefore, a difference in the crosslink density occurs partially. For this reason, when the molecular weight of the polyester is increased for the purpose of improving the offset resistance, the elasticity becomes too large, and the smoothness of the toner fixing surface is deteriorated for a full-color toner. On the other hand, if the molecular weight of the polyester is reduced for the purpose of improving the smoothness of the toner fixing surface, on the contrary, the offset resistance deteriorates.

Further, in these disclosed methods, the amount of the metal compound is reduced by using a polyester crosslinked with a trivalent or higher alcohol or carboxylic acid, but as described above, the trivalent or higher alcohol or carboxylic acid is used. It is very difficult to control the viscoelasticity of polyester with acid.

Therefore, the present inventors, as a result of intensive research, during the synthesis of the polyester resin, by performing a cross-linking reaction using a silane coupling agent, by adding Si in the main chain of the polyester resin and further having a three-dimensional structure, Also for full-color toners, it is possible to expand the fixing temperature range without impairing the smoothness of the toner fixing surface.

 The present inventors have inferred the reason for this as follows.

In JP-A-58-211160, at the time of polyester synthesis,
A crosslinked structure is obtained by using a metal oxide, a metal salt, a hydroxide, an alkoxide, and a chelate compound in combination with a trivalent or higher alcohol or a trivalent or higher carboxylic acid. However, according to the application, these metal compounds can bind only to the carboxyl group in the polyester resin. Therefore, only a bond with the carboxyl group at the unreacted portion of the trivalent or higher carboxylic acid or the carboxyl group at the terminal of the molecular chain can be expected.

Therefore, this method can partially form a three-dimensional structure, but cannot form a fine mesh structure.

Therefore, the fixability is improved to some extent but is not sufficient. In addition, it is possible to obtain a three-dimensional structure by metal cross-linking by using a large amount of a trivalent or higher carboxylic acid and forming a large amount of unreacted carboxyl groups. But
Since the crosslinking with a trivalent or higher carboxylic acid proceeds simultaneously, the polyester resin obtained here becomes very rigid and has a poor smoothness on the toner fixing surface, and cannot be used for a full-color toner.

According to the method of the present invention, since a silane coupling agent is used at the time of polyester synthesis, Si metal enters the polyester main chain uniformly, and the metal becomes a branch point and has a three-dimensional structure. Also, since the reaction between the coupling agent and the acid or alcohol proceeds rapidly, a uniform and beautiful network structure can be formed. Therefore, the fixing temperature range can be expanded without impairing the smoothness of the fixing surface for a full-color toner. Think that it became possible.

As the polyhydric alcohol component of the polyester resin used in the present invention, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol,
2,3-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, pentaerythritol diallyl ether, trimethylene glycol, 2-ethyl-1, 3-hexanediol, hydrogenated bisphenol A, and a bisphenol derivative represented by the following formula; (Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2
~ 10. ) And the like.

As the polycarboxylic acid component, fumaric acid, maleic acid,
Citraconic acid, unsaturated dicarboxylic acids such as itaconic acid, or anhydrides thereof, succinic acid, adipic acid,
Examples thereof include dicarboxylic acids such as sebacic acid and azelaic acid, and acid anhydrides thereof, aromatic dicarboxylic acids such as phthalic acid and terephthalic acid, and lower alkyl esters thereof. In addition, glycerin, sorbite, sorbitan, and the like as trivalent or higher alcohols, and trimeric acid, pyromellitic acid, and the like as trivalent or higher acids, may be used in combination with the coupling agent described below. .

Examples of the silane coupling agent used in the present invention include alkyltrialkoxysilanes such as methyltrimethoxysilane and methyltriethoxysilane; alkenyltrialkoxysilanes such as vinyltrimethoxysilane, vinyltris (methoxyethoxy) silane and vinylacetoxysilane. Methacryloxyalkyl trialkoxysilanes such as γ-methacryloxypropyltrimethoxysilane; glycidoxyalkyltrialkoxysilanes such as γ-glycidoxypropyltrimethoxysilane; γ-mercaptopropyltrimethoxysilane; γ-
Mercaptoalkyltrialkoxysilanes such as mercaptopropylmethyldimethoxysilane; mercaptoalkylalkyldialkoxysilanes; alkyltrichlorosilanes such as methyltrichlorosilane: chloroalkyltrialkoxysilanes such as γ-chloropropyltrimethoxysilane; γ- Chloroalkylalkyldialkoxysilanes such as chloropropylmethyldimethoxysilane; γ-aminopropyltriethoxysilane,
aminoalkyl trialkoxysilanes such as γ-aminopropyltriethoxysilane; aminoalkylalkyldialkoxysilanes such as γ-aminopropylmethyldiethoxysilane; γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ ( 2-aminoethyl)
Γ-amino such as aminopropyltriethoxysilane
(2-aminoalkyl) aminoalkyl trialkoxysilanes; γ- (2-aminoalkyl) such as γ- (2-aminoethyl) aminopropylmethyldimethoxysilane and γ- (2-aminoethyl) aminopropylmethyldiethoxysilane ) Aminoalkylalkyldialkoxysilanes; N-methylaminopropyltrimethoxysilane,
Alkylaminoalkyl trialkoxysilanes such as N-methylaminopropyltrimethoxysilane; dialkylaminoalkyltrialkoxysilanes such as N, N dimethylaminopropyltrimethoxysilane and N, N diethylaminopropyltrimethoxysilane; P-aminophenyl Aminophenylalkoxysilanes such as trimethoxysilane and P-aminophenyltriethoxysilane; N, N
Dialkylaminophenyl trialkoxysilanes such as dimethylaminophenyltrimethoxysilane and N, N dimethylaminophenyltriethoxysilane; aminoalkylaminoalkyl such as aminoethylaminomethylphenethyltrimethoxysilane and aminoethylaminomethylthiophenetriethoxysilane Phenethyl trialkoxysilanes; hexaalkyldisilazane such as hexamethyldisilazane, hexaethyldisilazane; γ-
Anilinoalkyl trialkoxysilanes such as anilinopropyltrimethoxysilane and γ-anilinopropyltriethoxysilane; bis-hydroxyalkylaminoalkyltrialkoxysilanes such as bis (2-hydroxyethyl) aminopropyltriethoxysilane; Bistrialkoxysilylalkylamines such as bis [3- (triethoxysilyl) propyl] amine; bistrialkoxysilylalkylalkenediamines such as bis [3- (trimethoxysilyl) propyl] ethylenediamine; trimethoxysilylpropylethylcarbamate; Trialkoxysilylalkylaryl carbamates such as triethoxysilylpropylethylcarbamate; γ-ureidopropyltrimethoxysilane;
ureidoalkyl trialkoxysilanes such as γ-ureidopropyltriethoxysilane; imidazolealkyltrialkoxysilanes such as γ-imidazolepropyltrimethoxysilane and γ-imidazolepropyltriethoxysilane; trimethoxysilylpropyldiethylenetriamine and triethoxysilylpropyl Trialkoxysilylalkyldiethylenetriamines such as diethylenetriamine; 1-trimethoxysilyl-2-1
-(P, m-aminoethylmethyl) phenylmethane, 1-
Trialkoxysilyl- such as triethoxysilyl-2- (p, m-aminoethylmethyl) phenylpropane
2-1- (p, m-aminoalkylalkyl) phenylalkanes; methyl-3- [2- (3-trimethoxysilylpropylamino) ethylamino] 3-propionate, ethyl-3- [2- (3- Carboxylic acid or carboxylate of alkyl [(trialkoxysilylalkylamino) alkylamino] alkyl such as triethoxysilylpropylamino) ethylamino] 3-propionate; N-β- (N-vinylbenzylaminoethyl) -γ
Alkyl or alkenylbenzylaminoalkylaminoalkyl trialkoxysilane hydrochlorides such as -aminopropyltrimethoxysilane hydrochloride; β-trichlorosilyl-4-ethylpyridine, β-trichlorosilyl-4
Trichlorosilylalkylpyridines such as -propylpyridine; acryloxyldialkyl (trialkoxysilylalkyl) ammonium such as methacryloxyldimethyl (3-trimethoxysilylpropyl) ammonium chloride and methacryloxyldiethyl (3-triethoxysilylpropyl) ammonium chloride Chlorides; alkyldialkyl [3-trialkoxysilyl) alkyl] ammonium chlorides such as octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride; trichlorides such as N- (trimethoxysilylpropyl) ethylenediaminetriacetate sodium salt Alkoxysilylalkyl ethylenediamine triacetate sodium salts and the like.

The alcohol component used in the present invention is 20 to 60 mo
It is desirable that the acid component is contained in an amount of 20 to 60 mol% and the silane coupling agent is contained in an amount of 1 to 60 mol%, preferably 5 to 40 mol%. It is desirable that the content of the trivalent or higher valent acid or alcohol component is 0 to 15 mol%, preferably 0 to 10 mol%. When the amount of the silane coupling agent is 1 mol% or less, there is no effect of improving the anti-offset property, and when the amount is 60 mol% or more, the cross-linking density is too high, thereby impairing the smoothness of the fixing surface, or bonding between the silane coupling agents. The formation of a siloxane bond leads to poor fixability.
If the trivalent acid or alcohol is at least 15 mol%, the smoothness of the toner fixing surface will be impaired.

Among those specifically listed above, polyhydric alcohol components that can exert more effects in the present invention include:
Hydrogenated bisphenol A, bisphenol derivative represented by the following formula: (Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2
~ 10. The polyvalent carboxylic acid component includes lower alkyl esterified products such as fumaric acid, maleic acid, succinic acid, phthalic acid, terephthalic acid and trimellitic acid.

Examples of the silane coupling agent include alkyl trialkoxy silanes, alkenyl trialkoxy silanes, amino alkyl trialkoxy silanes, amino alkyl alkyl dialkoxy silanes, bishydroxyalkyl aminoalkyl trialkoxy silanes, and bis trialkoxy silanes. Alkylamines, bistrialkoxysilylalkylalkenediamines, hexaalkyldisilazane, alkyl [(trialkoxysilylalkylamino) ethylamino] alkyl carboxylate, glycidoxyalkyl trialkoxysilanes, trialkoxysilylalkyl And alkyl carbamates.

The reason for this is that, since a silane coupling agent is used during the synthesis of the polyester, Si metal enters the polyester skeleton uniformly, and this coupling agent becomes a branch point to form a uniform network structure. In particular, the use of a lower alkyl ester of an acid which undergoes transesterification by dealcoholization suppresses the reaction between the silane coupling agent and water and facilitates uniform introduction of Si metal into the polyester skeleton. is there.

Another reason is that a polyester obtained by using a lower alkyl ester of the acid, an alcohol, and a silane coupling agent has excellent charging characteristics.

Another reason is that a polyester obtained by using a lower alkyl ester of the acid, an alcohol and a silane coupling agent has excellent fluidity, does not cause aggregation, and has excellent impact resistance.

The production method of the polyester resin, by using the compound (under nitrogen gas in many cases) Under an inert gas atmosphere, carried out at normal pressure to reduced pressure (0~-750mmH ₂ O). While stirring, the temperature is raised to 60 to 200 ° C, preferably 80 to 180 ° C,
Perform the reaction for ~ 15 hours. Water or alcohols generated by the condensation polymerization are taken out of the system together with the inert gas while supplying the inert gas into the system so that the condensation polymerization proceeds.

For example, the compound is charged into a reaction vessel equipped with a stirrer, a condenser, a thermometer, and an inert gas introduction pipe. Next, gas replacement is performed by introducing an inert gas. After completion of the gas replacement, the reaction temperature is raised to a predetermined temperature by continuously flowing the inert gas, and the condensation polymerization reaction is carried out with stirring for 6 to 15 hours. Water or alcohol generated by the condensation polymerization reaction is condensed and recovered by a condenser outside the system. At the end of the reaction, the temperature is lowered to stop the reaction, and the mixture is cooled to room temperature to obtain a polyester resin.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples.

Resin production example 1 Was placed in a 2 l four-necked round bottom flask equipped with a thermometer, a Teflon-coated stirring blade, a glass nitrogen introducing tube, and a condenser. Next, the flask was placed in a mantle heater, nitrogen gas was introduced from a glass introduction tube to keep the inside of the reactor in an inert atmosphere, and the temperature was raised to 170 ° C. While maintaining the temperature at 170 ° C., a condensation polymerization reaction was performed for 12 hours. At this time, the nitrogen gas was kept flowing, and the generated water and alcohol were condensed and recovered by a condenser.

 The polyester obtained here is referred to as resin A.

Resin production example 2 Was performed in the same manner as in Resin Production Example 1. The condition at this time is 180
The reaction was performed at 10 ° C. for 10 hours. The polyester obtained here is referred to as resin B.

Resin production example 3 Was placed in a 2 l four-neck round bottom flask equipped with a thermometer, a Teflon-coated stirring blade, a glass nitrogen introducing tube, a condenser, and a decompression device. After introducing nitrogen gas from the glass introduction tube to make the inside of the reactor an inert atmosphere, by changing the nitrogen gas introduction valve and the pressure reduction adjustment valve,
Maintaining the system inside -700mmH ₂ O. Thereafter, the reactor was placed in a mantle heater and maintained at 160 ° C. to perform a condensation polymerization reaction for 10 hours. The pressure at this time was -600mmH ₂ O.

 The polyester obtained here is referred to as resin C.

Resin production example 4 Was performed in the same manner as in Resin Production Example 1. The condition at this time is 220
The reaction was performed at 10 ° C. for 10 hours. The polyester obtained here is referred to as resin D.

Resin production example 5 Was performed in the same manner as in Resin Production Example 1. The condition at this time is 230
The reaction was performed at 9 ° C. for 9 hours. The polyester obtained here is referred to as resin E.

Example 1 A full-color toner for dry electrophotography was obtained by using a coloring agent and a charge control agent in the following amounts with respect to 100 parts by weight of resin A.

The production method is that the above-mentioned formulation amounts are sufficiently preliminarily mixed with a Henschel mixer, melt-kneaded at least twice with a three-roll mill, cooled, roughly crushed using a hammer mill to about 1-2 mm, and then air-cooled. It was pulverized to a particle size of 40 μm or less by a jet-type pulverizer. Furthermore, the obtained finely pulverized product is classified, 2 to 23 μm is selected so as to have a particle size distribution of the present invention, and a silica fine powder treated with hexamethyldisilazane as a flow improver is added to 100 parts by weight of each classified product. 0.5 parts by weight of an external additive was added to obtain a color toner.

Also, a vinylidene fluoride-tetrafluoroethylene copolymer (copolymerization weight ratio of 8: 2) and styrene-2-ethylhexyl acrylate-methyl methacrylate (copolymerization weight ratio: 45:12 parts by weight) were used for 8 to 12 parts by weight of the color toner. 20:35)
About 50% by weight in a 50:50 weight ratio, Cu
-Zn-Fe ferrite carrier (average particle size 48 m; 250 mesh pass, 350 mesh on 79 wt%; true density 4.5 g / cm
³ ) was mixed to make a total amount of 100 parts by weight to prepare a developer.
Considering color tone reproducibility and toner scattering, yellow,
The developer concentrations of the magenta, cyan, and black color toners were 9%, 8%, 10%, and 10%, respectively. This is CLC-1
(Full color copying machine manufactured by Canon Inc.), and an image endurance test was performed. As a result, a clear image with no offset and no fog was obtained even with a 20,000-sheet durability.

Example 2 It carried out similarly to Example 1 using resin B. as a result,
Even with a durability of 25,000 sheets, there was no offset and clear images without fog were obtained.

Example 3 It carried out similarly to Example 1 using resin C. as a result,
Even with 35,000 durable sheets, there was no offset and clear images without fog were obtained.

Comparative Example 1 The same procedure as in Example 1 was performed using resin D. As a result, low-temperature offset occurred when the number of durable sheets was 1,500. Further, the dispersion of the colorant of the cyan toner was poor, and the color reproducibility was poor.

Comparative Example 2 The same procedure as in Example 1 was performed using resin E. As a result, low-temperature offset occurred when the number of endurance sheets was 1,000. The fixing surface was not flat, and the color mixing was poor.

[Effects of the Invention] The present invention is intended for a full-color toner by synthesizing a polyester resin by using a silane coupling agent to cause a cross-linking reaction, thereby adding Si into the main chain of the polyester resin and giving the polyester resin a three-dimensional structure. However, the smoothness of the toner fixing surface is not impaired, the fixing temperature range is expanded,
The toner can give a clear image without fogging.

Claims (4)

(57) [Claims] 1. A polyester resin synthesized using at least a polyhydric alcohol component, a polycarboxylic acid component, and a silane coupling agent, wherein the polyester resin comprises:
A polyester resin for electrophotographic toner, having a three-dimensional structure having a bond with Si metal by a crosslinking reaction with the silane coupling agent. 2. When a polyester resin is synthesized from at least a polyhydric alcohol component and a polyvalent carboxylic acid component, the polyester resin has a three-dimensional structure having a bond with Si metal by a crosslinking reaction using a silane coupling agent. A method for producing a polyester resin for an electrophotographic toner, comprising obtaining a polyester resin as described above. 3. An electrophotographic toner containing at least a colorant and a polyester resin, wherein the polyester resin contains a silane coupling agent when synthesizing the polyester resin from at least a polyhydric alcohol component and a polycarboxylic acid component. A toner for electrophotography, which has a three-dimensional structure having a bond with Si metal by being subjected to a crosslinking reaction. 4. The electrophotographic toner according to claim 3, wherein the electrophotographic toner is a color toner for forming a color image.