JPH0366665B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] 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 excellent low-temperature fixing properties, offset resistance, blocking resistance, and the like. [Prior Art] Various methods have been known as electrophotography, but a common method is to form an electrical latent image on a photoreceptor by various means using a photoconductive substance, and then There is a method in which such a latent image is developed using toner, transferred onto an image support such as paper as necessary, and then fixed by heating, pressure, or a solvent to obtain an image. Recently, there has been a demand for high-speed fixing performance in order to improve the efficiency of copying operations. Considerations have been made to use thermoplastic resins that are easy to heat-fix. However, if the softening point of the resin is simply lowered, there is a problem that the toner particles will aggregate during storage or use, resulting in a blocking phenomenon. A fixing method using a good heated roller has come into use. The heated roller method has higher thermal efficiency than the oven fixing method, so it can fuse the toner in a shorter time, but there is a problem with the occurrence of the so-called offset phenomenon in which the toner adheres to the heated roller, and we have solved this problem. It is desired to develop a binder resin for toner that can do this. As conventional binder resins, styrene-acrylic acid ester copolymers and styrene-butadiene copolymers are generally known, but these vinyl copolymers are generally inferior in offset resistance and low-temperature fixing properties. There are many things. On the other hand, bisphenol type epoxy resin has a lower molecular weight than the vinyl copolymer, so
If this is used, a toner with excellent low-temperature fixing properties can be obtained, but offset resistance tends to be lowered due to the low melt viscosity of the resin. Recently, various polyester resins have been proposed as toner binder resins that have excellent offset resistance and low-temperature fixing properties. Amorphous polyester resins obtained by using etherified diphenols as the main alcohol component have been studied, as typified by No. 59-29255 and Japanese Patent Application Laid-open No. 59-29256. However, according to the studies of the present inventors, in order to maintain the softening point of the polyester resin at a high level, etherified diphenols are used as the main alcohol component, and the blocking resistance of the resulting toner is improved. Although the objective is to improve offset resistance, there is still room for improvement in low-temperature fixing properties. [Problems to be Solved by the Invention] The present inventors used etherified diphenols as the main alcohol component to maintain a high softening point of the resin, thereby easily achieving a balance between blocking resistance and low-temperature fixing properties. The aim was to develop a polyester resin that could maintain the In other words, the present invention solves the problems that could not be solved with the prior art, namely, the required performances of an electrophotographic toner composition containing a polyester resin as a binder, such as offset resistance, blocking resistance, and low-temperature fixing property. In view of the current situation where an electrophotographic toner composition that satisfies all the performance requirements in a well-balanced manner and is particularly suitable for high-speed machines has not been obtained, the aim is to develop a new electrophotographic toner composition that can solve various problems. That is. Generally, it is expected that improving only the low-temperature fixability of an electrophotographic toner composition can be achieved by lowering the softening point and molecular weight of the binder used. Therefore, the present inventors
29255 and JP-A-59-29256, various modified polyester resins were produced by introducing a monocarboxylic acid component into the polyester resins described in JP-A No. 59-29256, and the toner performance of these resins was evaluated. It has not been possible to simultaneously satisfy the above characteristics. By the way, the present inventors have solved all of the above problems when using a polyester resin containing a specific polyol component, that is, a polyester resin obtained by using rosin glycidyl ester as one of the components, as a binder. The applicant has already filed a patent application because of this knowledge. In addition to this knowledge, the present inventors have discovered that when using a monocarboxylic acid as a component of the polyester resin, in addition to the technical effects of the applicant's previous application, low-temperature fixing can be achieved. The present invention has been completed for the first time based on the surprising fact that the performance of the invention is further improved. [Means for Solving the Problems] The present invention relates to an electrophotographic toner composition having excellent low-temperature fixing properties, offset resistance, blocking resistance, and the like. That is, the present invention provides () an electrophotographic toner comprising a colorant dispersed in a binder resin, in which the binder resin includes (1) an acid component of monocarboxylic acids and dicarboxylic acids; (2) an alcohol component of rosin glycidyl ester; Etherified diphenols and diols without a phenyl nucleus, and (3) a crosslinking component consisting of trivalent or higher polycarboxylic acids and/or trivalent or higher polyols, and the content of each alcohol component in the total amount of alcohol components 5-50 mol% of rosin glycidyl ester, etherified diphenols 20-95
Mol% and diols without phenyl nucleus 0
~30%, and the content of the crosslinking component is 0.5 to 20% by weight in the polyester resin, an electrophotographic toner composition having excellent low temperature fixing properties; () In an electrophotographic toner comprising a colorant dispersed in a binder resin, the binder resin includes (1) the acid component is monocarboxylic acids and dicarboxylic acids, (2) the alcohol component is rosin glycidyl ester, etherified diphenol, and diols having no phenyl nucleus, and (3) a crosslinking component consisting of trivalent or higher polycarboxylic acids and/or trivalent or higher polyols, and the content of each alcohol component in the total amount of alcohol components is rosin glycidyl ester. 5-50 mol% of etherified diphenols 20-95
Mol% and diols without phenyl nucleus 0
~30%, and contains a non-linear polyester resin in which the crosslinking component content is 0.5 to 20% by weight in the polyester resin, and further contains an organic polyvalent metal compound in an amount of 0.2 to 4% by weight based on the binder resin. The present invention relates to an electrophotographic toner composition having excellent low-temperature fixing properties. [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, and methylhexahydrophthalic acid. Examples include hydrophthalic acid, maleic acid, fumaric acid, succinic acid, adipic acid, and acid anhydrides thereof. Monocarboxylic acids include palmitic acid, stearic acid, benzoic acid, chlorobenzoic acid, dichlorobenzoic acid, paratertiary butylbenzoic acid,
Examples include cyclohexanecarboxylic acid, toluic acid, and rosins, but benzoic acid, paratertiary leachable benzoic acid, and rosins are preferred in consideration of the softening point and cost of the resulting polyester binder. Note that rosins refer to various types listed as raw materials for rosin glycidyl esters, which will be described later. The above monocarboxylic acids are used to improve the low-temperature fixability of the resulting toner, and are essential components in the polyester binder of the present invention. The amount of the monocarboxylic acids used is 5 to 65 mol% in the carboxylic acid component. If the amount used is less than 5 mol%, there is little effect of improving low-temperature fixing properties, and if it exceeds 65 mol%, the glass transition point and offset resistance of the resulting polyester resin tend to decrease. Therefore, neither is preferable. The rosin glycidyl ester used as the alcohol 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 udon rosin, as well as hydrogenated rosins obtained by modifying these rosins, disproportionated rosins, and the like. Naturally, active ingredients of rosin such as abietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, and isopimaric acid can also be used. Further, as the organic amines, tertiary amines or onium salts thereof are preferable, and specific examples of the tertiary amines include triethylamine,
Examples include dimethylbenzylamine, methyldibenzylamine, tribenzylamine, dimethylaniline, dimethylcyclohexylamine, methyldicyclohexylamine, tripropylamine, tributylamine, N-phenylmorpholine, N-methylpiperidine, and 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 obtain 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 total amount of the polyol components (however, trivalent or higher polyols used as crosslinking agents are not included) 5 to 50 mol% of rosin glycidyl ester, preferably 10 to 30 mol% based on 100 mol%
It is said that In the present invention, the etherified diphenols used as the main alcohol component are diols obtained by addition reaction of bisphenol A and ethylene oxide or propylene oxide, and the average number of moles of the alkylene oxide added is 1 mole of bisphenol A. The amount of 2 to 16 moles per 100 mol per 100 ml can be suitably used. Since the amount used affects the softening point of the resulting polyester resin, it is usually 20 to 95 mol%, preferably 50 to 90 mol% of the polyol component. If the amount of etherified diphenols used exceeds the above range, the amount of modification by the rosin glycidyl ester will decrease, so that a polyester resin with a good balance of blocking resistance and low-temperature fixing properties, which is the object of the present invention, can be obtained. This is not desirable because it makes it 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. Here, the diols include ethylene glycol,
Examples include diethylene glycol, triethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 1,6-hexanediol. The amount used is usually 0 to 30 mol%, preferably 0 to 20 mol% in the polyol component.
It is said that Examples of trivalent or higher polycarboxylic acids or trivalent or higher polyols used as a crosslinking component in the present invention include the following. The latter include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol,
Examples include sorbitol and diglycerin.
Examples of the former include trimellitic acid, pyromellitic acid, and acid anhydrides corresponding to these. Since the crosslinking component affects the offset resistance of the resulting polyester resin, the amount used is usually 0.5 to 20% by weight of the polyester resin. In the method for producing the polyester resin used as a binder in the present invention, the carboxylic acids, the alcohols, and the crosslinking component are simultaneously charged within the amount ranges described above, and in the presence or absence of a reaction catalyst such as an organic tin-based compound. A method of heat-reacting carboxylic acids and alcohols in the presence or absence of the catalyst within the above-mentioned amount range, and crosslinking within the above-mentioned amount range during or after the reaction. The reaction can be carried out by adding the components and further heating to advance the reaction. In the present invention, the target binder resin can be obtained in high yield regardless of the presence or absence of a solvent, but in order to smoothly distill the water produced during the reaction out of the system, for example, toluene,
Solvents such as xylene can also be used. The reaction temperature and time are appropriately determined in consideration of the yield of the product, and are usually 100 to 300°C for 1 to 20 hours. In addition, if a solvent is used during the reaction, the solid content can be obtained by distilling it off under reduced pressure. As described above, the polyester resin of the present invention can be easily obtained. The end point of the reaction may be appropriately determined by measuring the acid value of the produced resin, the content of insoluble matter in the solvent, the gel permeation chromatogram, the softening point, etc. 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 fixability, offset resistance, blocking resistance, etc. The softening point of this material is preferably 110 DEG 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 offset resistance is disadvantageously reduced. In addition, the glass transition temperature of the resin is
50-80°C is preferred. If the temperature is less than 50°C, the blocking resistance will be lowered, and if it exceeds 80°C, the low-temperature fixing property will be lowered, which is not preferable. The resin may not only be completely soluble in tetrahydrofuran, but also contain about 80% of the insoluble matter 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 below 40, preferably 20
The following shall apply. However, as will be 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 yellow, ultramarine blue, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, and monastral red. . 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 such as cobalt, nickel, and manganese G, and other known ferromagnetic materials. I can do it. 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, offset resistance can be further improved by blending an organic polyvalent metal compound in addition to the polyester resin. It can improve your sexuality. The compound is capable of reacting with the carboxyl group in the polyester, and includes, for example, magnesium acetate, calcium acetate, basic aluminum acetate, calcium stearate, zinc stearate, etc.; aluminum isopropoxide, aluminum-n-butoxide, etc.; Examples include chelate compounds such as acetylacetonate, 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, problems that could not be sufficiently solved by the prior art, namely, the requirements for electrophotographic toner compositions, can be solved. We have overcome the current situation where there is no toner composition for electrophotography that can simultaneously satisfy all of the performance characteristics of offset resistance, blocking resistance, and low-temperature fluidity in a well-balanced manner, and that is particularly suitable for high-speed machines. A novel electrophotographic toner composition can be provided. By the way, the reason why a polyester resin obtained by using a specific amount of a monocarboxylic acid such as benzoic acid as a carboxylic acid component and a specific amount of rosin glycidyl ester as an alcohol component has such an advantage is still unclear. It is assumed that this is based on the following synergistic effect. (1)
By using monocarboxylic acids as the polyester component, the abundance ratio of low molecular weight components that contribute to low temperature fixing properties increases; (2) By using rosin glycidyl ester, the presence ratio of low molecular weight components that contributes to low temperature fixing properties increases, as in (1). (3) Since the rosin glycidyl ester has a sterically bulky and rigid hydrophenanthrene skeleton, the softening point of the polyester resin can be maintained high, and moreover, this skeleton is on the side of the polyester resin. This is predicted to be due to its location in the chain. Furthermore, since the polyester resin has excellent dispersibility for various colorants, it has the advantage that the charging characteristics of the toner are stabilized and the toner development characteristics are significantly improved. The present invention will be described in detail below with reference to manufacturing agents, examples, and comparative examples, but the present invention is not limited to these examples. In each example, all parts and percentages are based on weight unless otherwise specified. Reference example (Production of disproportionated rosin glycidyl ester) 500 ml equipped with a stirring device and reflux condenser
100 g of disproportionated rosin (acid value 162, softening point 79°C) with a purity of 87% (13% is unsaponifiable matter), 200 g of epichlorohydrin, and 0.1 g of benzyltrimethylammonium chloride were added to Kolben, and the mixture was allowed to react at 80°C for 4 hours. Ta. Then, at the same temperature, add granular sodium hydroxide.
16 g was added in portions, the temperature was raised to 100°C, and the reaction was continued for an additional 2 hours. After removing the precipitated salt, unreacted epichlorohydrin was distilled off from the liquid using a rotary evaporator, and volatile components were completely removed under conditions of 2 mmHg and 120°C to obtain the title pale yellow oil (yield 97.2%). I got it. The oxidation of this product was 0, the epoxy equivalent was 452, and the purity was 84% in terms of epoxy equivalent. Production Example 1 36.2 g of disproportionated rosin glycidyl ester obtained in Reference Example, 127.9 g of terephthalic acid, 313.2 g of polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane, triethylene 7.5 g of glycol and 0.2 g of dibutyltin oxide were charged and reacted for 8 hours at 240° C. in a nitrogen stream. After confirming that the acid value was approximately 13, 28.8 g of trimellitic anhydride was further added to continue the reaction. Using a flow tester, it was confirmed that the predetermined softening point had been reached, and the reaction was terminated (the softening point was measured by measuring the temperature at the time of 4 mm penetration using a flow tester; the same applies hereinafter). . The glass transition point of the obtained resin is 75℃, and the softening point is
It was 150℃. Production Examples 2 to 7 and Comparative Production Examples 1 to 4 Polyester resins were 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 were changed as shown in Table 1. Table 1 shows the measurement results of resin constants.

【table】

[Table] Production Examples 8 to 14 and Comparative Production Examples 5 to 8 The types of starting materials and the amounts used were the same as in Production Examples 1 to 7 and Comparative Production Examples 1 to 4, respectively, and the reaction was carried out using A polyester resin was obtained in the same manner as in Production Example 1, except that the process ended when the values shown in the table were reached. The measurement results of resin constants are shown in the second part.

[Table] Example 1 Carbon Black MA#100 (Mitsubishi Chemical Industries, Ltd.) was added to 100 parts by weight of the polyester resin of Production Example 1.
4 parts by weight of Viscol 550P (polypropylene wax manufactured by Sanyo Chemical Industries, Ltd.) were thoroughly mixed and kneaded using an extruder. Then, after cooling, the powder was coarsely pulverized to a size of 1 cm square, finely pulverized using a jet mill, and then classified using an air classifier to produce a toner having an average particle size of 13 to 15 μm. For 5 parts by weight of this toner, add 95 parts by weight of iron powder carrier.
A developer was prepared by adding parts by weight, and an electrostatic image was developed using an electrophotographic copying machine. This was transferred onto plain paper, the temperature of the fixing roller whose surface was made of Teflon was varied to fix it, and the image was rubbed with an eraser (10 reciprocations).Fixing rate (%)
was measured. At the same time, offset resistance was also evaluated by visual judgment. In Table 2, symbols ○,
Δ and × mean no offset, very slight offset, and considerable offset, respectively. On the other hand, the evaluation of blocking resistance was as follows: 20g of toner
was left in a constant temperature bath at 50℃ for 24 hours, and after cooling at room temperature,
Judgment was made based on the degree of clumping. Examples 2 to 7 and Comparative Examples 1 to 4 The polyester resins of Production Examples 2 to 7 and Comparative Production Examples 1 to 4 were each made into toner in the same manner as in Example 1, and the performance thereof was evaluated. The results are shown in Table 3.

[Table] Example 8 4 parts by weight of Carbon Black MA#100, 2 parts by weight of Viscol 550P, and 1 part by weight of aluminum acetylacetonate were thoroughly mixed with 100 parts by weight of the polyester resin of Production Example 8, and the mixture was placed in an extruder. It was mixed with 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. Examples 9 to 14 and Comparative Examples 5 to 8 The polyester resins of Production Examples 9 to 14 and Comparative Production Examples 5 to 8 were each made into toner in the same manner as in Example 8, and the performance thereof was evaluated. The results are shown in Table 4.

[Table] [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, that is, the softening point of the resin can be improved. This can solve the problem that it is difficult to simultaneously satisfy both the blocking resistance and low-temperature fixing properties of the toner while maintaining high performance. Therefore, when a polyester resin containing resin glycidyl ester, monocarboxylic acids, etc. is used as a binder, it is possible to simultaneously satisfy all the properties of offset resistance, blocking resistance, and low temperature fixing property in a well-balanced manner, especially in high-speed printing machines. This has the effect that an electrophotographic toner composition suitable for various uses can be obtained.

Claims (1)

[Scope of Claims] 1. An electrophotographic toner comprising a colorant dispersed in a binder resin, in which the binder resin includes (1) an acid component containing monocarboxylic acids and dicarboxylic acids, (2) an alcohol component containing rosin glycidyl ester, Etherified diphenols and diols without a phenyl nucleus, and (3) a crosslinking component consisting of trivalent or higher polycarboxylic acids and/or trivalent or higher polyols, and the content of each alcohol component in the total amount of alcohol components rate of rosin glycidyl ester 5
~50 mol%, etherified diphenols 20-95 mol% and diols without phenyl nucleus 0~
An electrophotographic toner composition having excellent low-temperature fixability, characterized in that it contains a non-linear polyester resin in which the content of the crosslinking component is 0.5 to 20% by weight in the polyester resin. 2. In an electrophotographic toner comprising a colorant dispersed in a binder resin, the binder resin includes (1) the acid component is monocarboxylic acids and dicarboxylic acids, (2) the alcohol component is rosin glycidyl ester, etherified diphenols, and phenyl. diols without a nucleus, and (3) a crosslinking component consisting of trivalent or higher polycarboxylic acids and/or trivalent or higher polyols, and the content of each alcohol component in the total amount of alcohol components is rosin glycidyl ester 5
~50 mol%, etherified diphenols 20-95 mol% and diols without phenyl nucleus 0~
30 mol%, and contains a non-linear polyester resin in which the crosslinking component content is 0.5 to 20% by weight in the polyester resin, and further contains an organic polyvalent metal compound in an amount of 0.2 to 4% by weight based on the binder resin. An electrophotographic toner composition having excellent low-temperature fixing properties.