JPS62226161A - Electrophotographic toner composition superior in low temperature fixability - Google Patents

Abstract

PURPOSE:To obtain satisfactory performances in both of blocking resistance without lowering the softening point of a binder resin, and fixability at low temperature at the same time by specifying acid components, polyol components, and cross-linking components as a binder resin. CONSTITUTION:The binder resin contains a nonlinear polyester resin composed of dicarboxylic acids as the acid components; rosin glycidyl ester, etherified diphenols, and diols having no phenol ring as the polyol components in proportions of 5-50mol%:95-20mol%:0-30mol%, respectively, of the total mols of the polyol components; and trivalent or higher polycarboxylic acids and such polyols as the crosslinking components, in an amount of 0.5-20wt% of the total polyester resin, thus permitting every requirement of offset resistance, blocking resistance, and low temperature fixability to be satisfied at the same time in good balance.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to an electrophotographic toner composition.

More specifically, the present invention relates to an electrophotographic toner composition containing a specific polyester resin as a binder and having good low-temperature fixing properties, anti-offset properties, anti-blocking properties, etc.

[Prior Art] Various methods have been known as electrophotography, but
A common method is to use a photoconductive substance to form an electrical latent image on a photoreceptor by various means, and then develop the latent image with toner to form an electrical latent image on an image support such as paper, if necessary. There is a method of obtaining an image by transferring the image to a paper and then fixing it using heat, pressure, or a solvent.

Recently, high-speed fixing performance has become required in order to improve the efficiency of copying operations. Considerations have been made to use thermoplastic resins that have the same properties and are easily heat-fixed. However, if the softening point of the resin is simply lowered, there is a problem that toner particles will aggregate during storage or use, resulting in a blocking phenomenon. Fixing methods using heated rollers have come to be practiced.

The single heating roller type has higher thermal efficiency than the oven fixing method, so it can fix the toner in a shorter time, but the problem is that the so-called offset phenomenon occurs, where the toner sticks to the heating roller. It is desired to develop a binder resin for toner that can solve these problems. Conventional binder resins are usually styrene.
Acrylic acid ester copolymers and styrene-butadiene copolymers are known, but many of these vinyl copolymers are generally inferior in offset resistance and low-temperature fixing properties.

On the other hand, bisphenol-type epoxy resin has a lower molecular weight than the above-mentioned vinyl copolymer, so using it can replace a toner with excellent low-temperature fixing properties, but the low melt viscosity of the resin reduces offset resistance. There is a tendency.

In response to this, various polyester resins have recently been proposed as toner binder resins that are resistant to off-setting, have excellent dry properties, and low-temperature fixing properties.
Focusing on offset resistance, etc., JP-A-57-1098
As typified by Japanese Patent No. 25, polyester resins obtained by using etherified diphenols as the main alcohol component and modifying them with long-chain alkyl-substituted dicarboxylic acids have been studied.

However, according to studies conducted by the present inventors, the modifying components such as long-chain alkyl-substituted dicarboxylic acids significantly lower the softening point of the resulting polyester resin. However, the original purpose of the invention, which is to maintain the softening point of the resin at a high level when used as a resin, is not fully achieved, and as a result, it is difficult to maintain a balance with anti-blocking properties.

[Problems to be Solved by the Invention] However, the present inventors used etherified diphenols as the main alcohol component to maintain a high softening point of the resin, thereby achieving a balance between blocking resistance and low-temperature fixing properties. The aim was to develop a polyester resin that could be easily maintained.

In other words, the present invention solves all of the problems that could not be solved with the prior art, namely offset resistance, blocking resistance, and low-temperature fixing properties, which are the required performances for electrophotographic toner compositions containing polyester resin as a binder. In view of the current situation where an electrophotographic toner composition that satisfies the above performance in a well-balanced manner and is particularly suitable for high-speed machines has not been changed, the objective is to develop a new electrophotographic toner composition that can solve various problems. It is something.

The present invention aims to solve all of the above problems when a polyester resin containing a specific polyol component, that is, a polyester resin obtained using rosin glycidyl ester as one of the components, is used as a binder. I found out. The present invention was completed based on this new knowledge.

[Means for Solving the Problems] The present invention relates to an electrophotographic toner composition that has excellent low-temperature fixing properties, anti-offset properties, anti-blocking properties, and the like.

That is, the present invention provides (11) an electrophotographic toner in which a colorant is dispersed in a binder resin, in which the binder resin includes: (1) the acid component is a dicarboxylic acid; (2) the polyol component is a rosin glycidyl ester or an etherified diphenol; and (3) polycarboxylic acids whose crosslinking component is trivalent or higher and (
or) consisting of trivalent or higher polyols, and the content of each polyol component in the total amount of polyol components is 5 to 50 mol% of rosin glycidyl ester
, 95 to 20 mol% of etherified diphenols and 0 to 30 mol% of diols having no phenyl nucleus,
The content of the crosslinking component in the polyester resin is 0.5 to 2.
An electrophotographic toner composition with excellent low-temperature fixability characterized by containing 0% by weight of a non-linear polyester resin, and an electrophotographic toner comprising a binder resin (I[) and a colorant dispersed therein. The binder resin includes (1) the acid component is dicarboxylic acids, (2) the polyol component is rosin glycidyl ester, etherified diphenols, and diols having no phenyl nucleus, and (3) the crosslinking component is trivalent or higher. Polycarboxylic acids and (
or) consisting of trivalent or higher polyols, and the content of each polyol component in the total amount of polyol components is 5 to 50 mol% of rosin glycidyl ester
, 95 to 20 mol% of etherified diphenols and 0 to 30 mol% of diols having no phenyl nucleus,
The content of the crosslinking component in the polyester resin is 0.5 to 2.
Electrophotography with excellent low-temperature fixability, characterized by containing 0% by weight of a non-linear polyester resin and further containing 0.2 to 4% by weight of an organic polyvalent metal compound based on the binder resin. The present invention relates to toner compositions for

[Example] In the present invention, dicarboxylic acids used as acid components include orthophthalic acid, isophthalic acid, terephthalic acid, endomethylenetetrahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methyl Examples include xahydrophthalic acid, maleic acid, fumaric acid, succinic acid, adipic acid, and acid anhydrides thereof.

The rosin glycidyl ester used as a polyol component in the present invention is obtained by subjecting rosin and epihalohydrin to a heating reaction in the presence of an alkaline substance such as an organic amine. Examples of the rosin used include natural rosins such as gum rosin, tall oil rosin, and wood rosin, as well as hydrogenated rosins obtained by modifying these rosins, and disproportionated rosins. Naturally, active ingredients of rosin such as abietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, and isopimaric acid can also be used. The organic amines are preferably tertiary amines or onium salts thereof, and specific examples of the tertiary amines include triethylamine, dimethylbenzylamine, methyldibenzylamine, tribenzylamine, dimethylaniline, and dimethylcyclohexylamine. , methyldicyclohexylamine, tripropylamine, tributylamine, N-phenylmorpholine, N-methylpiperidine,
Examples include pyridine. Specific examples of onium salts of tertiary amines include tetramethylammonium chloride, benzyltriethylammonium chloride, allyltriethylammonium bromide, tetrabutylammonium chloride, methyltrioctylammonium chloride, trimethylamine hydrochloride, triethylamine hydrochloride, and pyridine hydrochloride. You can give them salt, etc.

As mentioned above, the purpose of using the rosin glycidyl ester is to maintain a high softening point of the resin by using etherified diphenols as the main alcohol component, and to create a polyester resin with a good balance of blocking resistance and low-temperature fixing properties. Therefore, the amount of rosin glycidyl ester used is naturally within a certain range, and usually the polyol component (however, trivalent or higher polyols used as a crosslinking agent is not included). 5 to 5% of rosin glycidyl ester based on 100 mol% of total
The content is 50 mol%, preferably 10 to 30 mol%, and more preferably 10 to 2θ mol%.

In the present invention, the etherified diphenols used as the main polyol component are diols obtained by addition-reacting bisphenol A with ethylene oxide or propylene oxide, and the average number of moles of the alkylene oxide added is 1 of bisphenol A. Those having an amount of 2 to 16 moles per mole can be suitably used.

The amount used affects the softening point of the obtained polyester resin, so it is usually 95 to 20 mol%, preferably 90 to 50 mol%, more preferably 9
The content is preferably 0 to 70 mol%.

If the amount of etherified diphenols used exceeds the above range, the amount of modification by the rosin glycidyl ester will decrease, making it possible to obtain a polyester resin with a well-balanced blocking resistance and low-temperature fixability, which is the objective of the present invention. This is not preferable because it becomes difficult to do so. Further, if the amount used is less than the above range, the softening point of the polyester resin will be lowered, which is not preferable.

In the present invention, the softening point of the resulting polyester resin can be adjusted as appropriate by using diols that do not have a phenyl nucleus as an optional component. Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, ■, 2-
Examples include butanediol, (1), 3-butanediol, 1,4-butanediol, and 1,6-hexanediol. The amount used is usually 0 to 30 mol%, preferably 1 to 20 mol%, more preferably 5 to 15 mol% in the polyol component.

Examples of trivalent or higher polycarboxylic acids or trivalent or higher polyols used as a crosslinking component in the present invention include the following.

Examples of the latter include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, diglycerin, and the like. Examples of the former include trimellitic acid, pyromellitic acid, and acid anhydrides corresponding to these.

Since the crosslinking component affects the anti-offset properties of the resulting polyester resin, the amount used is usually 0.5 to 20% by weight of the polyester resin.

In the production of the polyester resin used as a binder in the present invention, for example, dicarboxylic acids, rosin glycidyl esters, etherified diphenols, diols without a phenyl nucleus if necessary, and a crosslinking component,
A method in which they are simultaneously charged within the above usage amount range and heated to react in the presence or absence of a reaction catalyst such as an organotin compound, or dicarboxylic acids, rosin glycidyl esters, etherified diphenols, and if necessary Diols that do not have a phenyl nucleus are reacted by heating in the presence or absence of the catalyst in the amount range mentioned above, and a crosslinking component is added in the amount range mentioned above during or after the reaction, and then heated. This can be carried out by, for example, a method of proceeding with the reaction.

In the present invention, the target binder resin can be obtained in a high yield regardless of the presence or absence of a solvent, but in order to smoothly drain the water produced during the reaction out of the system, for example, toluene, xylene, etc. Solvents can also be used. The reaction temperature and time are appropriately determined in consideration of the yield of the product, and are generally 100 to 300°C for 1 to 20 hours. If a solvent is used during the reaction, a solid can be obtained by distilling it off under reduced pressure. As described above, the polyester resin of the present invention can be easily coated. The end point of the reaction may be appropriately determined by measuring the acid value of the produced resin, the content of insoluble soy in the solvent, the gel permeation chromatogram, or the softening point.

The physical and chemical constants of the polyester resin of the present invention are appropriately determined in consideration of the properties as an electrophotographic toner composition, ie, low-temperature fixing properties, anti-offset properties, anti-blocking properties, etc. The softening point of this material is preferably 110 to 180 DEG C. If it exceeds 180 DEG C., the low-temperature fixing properties are reduced, and if it is less than 110 DEG C., the anti-offset properties are disadvantageously reduced. Moreover, the glass transition temperature of the resin is preferably 50 to 80°C. If the temperature is less than 50°C, the blocking resistance will be reduced, and if it exceeds 80°C, the low-temperature fixing property will be reduced, both of which are not preferred. The resin may not only be completely soluble in tetrahydrofuran, but also contain about 80% of insoluble resin in the solvent. Further, since the acid value and hydroxyl value of the resin affect the electrical properties of the resulting toner under high humidity, it is usually preferable that the acid value and hydroxyl value are within the following ranges. That is, the acid value is 40 or less, preferably 20 or less. However, as described later, when an organic polyvalent metal compound is used, the number is preferably 5 to 40. The hydroxyl value is 30 or less, preferably 20 or less.

As the coloring agent used in the present invention, conventionally known coloring agents can be used as they are. Examples include carbon black, nigrosine dye, aniline blue, calco oil blue, chrome 20-, ultramarine blue, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green offsalate, lamp black, rose bengal, and Monastra red. It will be done. A carrier such as a magnetic substance is appropriately blended into the toner of the present invention. Examples of magnetic substances include metal powders such as iron, manganese, nickel, cobalt, and chromium, iron alloys such as ferrite and magnetite, alloys or compounds of cobalt, nickel, and manganese, and other known ferromagnetic materials. can.

If the polyester resin of the present invention is used as a binder, various required performances can be satisfied as described above, but if necessary, an organic polyvalent metal compound may be added to the polyester resin to further improve the offset resistance. It can improve your sexuality. The compound reacts with carboxyl groups in polyester, such as magnesium acetate, calcium acetate, basic aluminum acetate, calcium stearate, zinc stearate, etc.; aluminum isopropoxide, aluminum lobe toxide, etc.; aluminum acetyl acetonate,
Examples include chelate compounds such as nickel acetylacetonate and iron acetylacetonate; and various metal complexes such as zinc salicylate and chromium salicylate. Among these, acetylacetone metal complexes and salicylic acid metal complexes are preferred because they cause remarkable crosslinking reactions. In the present invention,
The amount of the organic polyvalent metal compound used is preferably 0.2 to 4% by weight based on the polyester resin.

As described above, according to the present invention, by using the specific polyester resin as a binder, the problems that could not be sufficiently solved by the prior art, namely, the required performance of electrophotographic toner compositions, can be solved. Breaking through the current situation of electrophotographic toner compositions that can satisfy all of the properties of offset resistance, blocking resistance, and low-temperature fluidity at the same time in a well-balanced manner, and especially suitable for high-speed machines, we have developed a revolutionary new toner composition. An electrophotographic toner composition can be provided. By the way, the reason why the polyester resin obtained by using a specific amount of rosin glycidyl ester as a polyester component has such an advantage is not yet clear, but the reason why the polyester resin obtained by using a specific amount of rosin glycidyl ester as a polyester component is not clear, It is expected that this is due to the nanthrene skeleton and that this skeleton is located in the side chain of the polyester resin. In other words, due to the rigidity of the hydrophenanthrene skeleton, the softening point of the resin hardly decreases,
Moreover, since it has excellent dispersibility of various colorants, etc., the charging characteristics of the toner are stabilized, and the toner development characteristics are significantly improved. Furthermore, since it is introduced into the side chain, it is thought that the low-temperature fixing properties of the polyester resin are improved.

Hereinafter, the present invention will be described in detail with reference to Reference Examples, Production Examples, Comparative Production Examples, Examples, and Comparative Examples, but the present invention is not limited to these. In each example, all parts and percentages are based on weight unless otherwise specified.

Reference Example (Manufacture of Disproportionated Rosin Glycidyl Ester) Disproportionated rosin (acid value 162, softening point 79°) with a purity of 87% (13% is unsaponifiable) was placed in a 500ml colben equipped with a stirrer and a reflux condenser. C) to.

g1 200 g of epichlorohydrin and 0.1 g of benzyltrimethylammonium chloride were added and reacted at 80° C. for 4 hours. Then, at the same temperature, add granular sodium hydroxide
g was added in portions, the temperature was raised to 100'C, and the reaction was further carried out for 2 hours. After filtering the precipitated salt, unreacted epichlorohydrin was distilled off from the solution using a rotary evaporator, and the volatile components were completely removed under the conditions of 2 m+sHg and 120°C to obtain the title pale yellow oil. rate 9
7.2%). The acid value of this product was O, the epoxy equivalent was 425, and the purity was 84% in terms of epoxy equivalent.

Production Example 1 Disproportionated rosin glycidyl ester 37 obtained in Reference Example
．． 8g, terephthalic acid L41. l g, polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane 295.2 g, triethylene glycol 7.5 g and dibutyltin oxide 0.2 g
was charged and reacted for 8 hours at 240°C under a nitrogen stream.

After confirming that the acid value was approximately 10, 29.0 g of trimellitic anhydride was further added to continue the reaction. It was confirmed with a flow tester that a predetermined softening point had been reached, and the reaction was terminated (the softening point was measured by measuring the temperature at 4 noe needle temperature with a flow tester, the same applies hereinafter).

The resulting resin has a glass transition point of 65°C and a softening point of 14.
It was 0°C.

Production Examples 2 to 5 and Comparative Production Example 1%2 A polyester resin was obtained by carrying out the reaction in the same manner as in Production Example 1, except that the types of starting materials and the amounts used thereof were changed as shown in Table 1. Table 1 shows the measurement results of resin constants.

Production Examples 6 to 10 and Comparative Production Examples 3 to 4 The types of starting materials and the amounts used thereof were the same as in Production Examples 1 to 5 and Comparative Production Examples 1 to 2, respectively, and the reactions were carried out with the acid values shown in Table 2. A polyester resin was obtained in the same manner as in Example 1, except that the process ended when the value reached . Table 2 shows the measurement results of resin constants.

[Margin below] Example 1 4 parts of carbon black MA'1OO (manufactured by Mitsubishi Chemical Corporation) were added to 100 parts by weight of the polyester resin of Production Example 1.
Thoroughly mix the heavy part and the double part of Viscol 550P (polypropylene wax manufactured by Sanyo Chemical Industries ■),
It was kneaded using an extruder. After cooling, the powder was coarsely ground to a size of 1 cm square, finely ground using a jet mill, and then classified using an air classifier to produce a toner having an average particle size of 13 to 15 square centimeters.

A developer was prepared by adding 95 parts by weight of iron powder carrier to 5 parts by weight of this toner, and an electrostatic image was developed using an electrophotographic copying machine. This was transferred onto plain paper and fixed by varying the temperature of a fixing roller whose surface was made of Teflon, which was then peeled off with a cellophane adhesive tape and the fixing rate was measured. Also, offset resistance was simultaneously evaluated by visual judgment. In Table 2, the symbols ○, Δ, and X mean no offset, very slight offset, and considerable offset, respectively.

On the other hand, in the evaluation of blocking resistance, 20g of toner was
The mixture was left in a constant temperature bath at ℃ for 24 hours, and after cooling at room temperature, the degree of agglomeration was evaluated.

Examples 2 to 5 and Comparative Examples 1 to 2 The polyester resins of Production Examples 2 to 5 and Comparative Production Examples 1 and 2 were formed into toners in the same manner as in Example 1, and the performance thereof was evaluated. The results are shown in Table 3.

[Left below] Example 6 4 parts by weight of carbon black HA''100, Viscoel 5 for 100 parts by weight of the polyester resin of Production Example 6
2 parts by weight of 50P and 1 part by weight of aluminum acetylacetonate were thoroughly mixed and kneaded using an extruder. Thereafter, a toner was prepared in the same manner as in Example 1, and its performance was evaluated. The results are shown in Table 4.

Example 7-IO and Comparative Examples 3 and 4 Production Example 7-IO
The polyester resins of Comparative Production Examples 3 and 4 were each made into toner in the same manner as in Example 6, and the performance thereof was evaluated. The results are shown in Table 4.

[Margins below] [Effects of the Invention] According to the present invention, the drawbacks of conventional electrophotographic toner compositions using polyester resins containing etherified diphenols as the main alcohol component, namely:
It is possible to solve the problem that it is difficult to simultaneously satisfy both the blocking resistance and low-temperature fixing properties of the toner while maintaining a high softening point of the resin. Therefore, when a polyester resin containing rosin glycidyl ester is used as a binder, it is possible to simultaneously satisfy all of the properties of offset resistance, blocking resistance, and low temperature fixing properties in a well-balanced manner, making it suitable for electrophotography especially for high-speed machines. This has the effect that the toner composition for use can be changed.

May 1985 250 1. Indication of the case 1988 Patent Application No. 68050 2. Name of the invention Toner composition for electrophotography with excellent low temperature fixing properties 3. Person making the amendment Relationship with the case Patent Applicant address: 2-chome, Hirano-cho, Higashi-ku, Osaka Name: Arakawa Chemical Industry Co., Ltd. Representative: Shinobu Takahashi 4 Agents: 540 yen 1 other person Subject of 5 amendments (1) “Detailed description of the invention” in the specification Contents of amendment in Column 6 (1) Amend "generally" to "generally" on page 5, line 2 of the specification.

(Correct the word ``solve vine'' in lines 7-8 on page 7 of 2 to ``can be solved.''

(3) Correct “outflow” in line 4 of page 15 to “distillate”.

(4) Table 1 on page 22 is amended as follows.

Claims (1)

[Scope of Claims] 1. An electrophotographic toner comprising a colorant dispersed in a binder resin, in which (1) the acid component is a dicarboxylic acid, (2) the polyol component is a rosin glycidyl ester or an etherified diphenol. and (3) polycarboxylic acids whose crosslinking component is trivalent or higher and (
or) consisting of trivalent or higher polyols, and the content of each polyol component in the total amount of polyol components is 5 to 50 mol% of rosin glycidyl ester
, 95 to 20 mol% of etherified diphenols and 0 to 30 mol% of diols having no phenyl nucleus,
The content of the crosslinking component in the polyester resin is 0.5 to 2.
An electrophotographic toner composition having excellent low-temperature fixing properties, the composition containing 0% by weight of a non-linear polyester resin. 2. In an electrophotographic toner comprising a colorant dispersed in a binder resin, the binder resin includes (1) an acid component containing dicarboxylic acids, and (2) a polyol component containing a rosin glycidyl ester, an etherified diphenol, and a phenyl nucleus. (3) polycarboxylic acids whose crosslinking component is trivalent or higher;
or) consisting of trivalent or higher polyols, and the content of each polyol component in the total amount of polyol components is 5 to 50 mol% of rosin glycidyl ester
, 95 to 20 mol% of etherified diphenols and 0 to 30 mol% of diols having no phenyl nucleus,
The content of the crosslinking component in the polyester resin is 0.5 to 2.
Electrophotography with excellent low-temperature fixability, characterized by containing 0% by weight of a non-linear polyester resin and further containing 0.2 to 4% by weight of an organic polyvalent metal compound based on the binder resin. Toner composition for use.