JPH0138305B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic toner composition. More specifically, the present invention relates to an electrophotographic toner composition containing a novel rosin-based polymer compound as a binder and having excellent blocking resistance and offset resistance. Conventionally, various methods have been known as electrophotography, but in general, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, and then the latent image is transferred to a toner. A method is known in which an image is obtained by developing the image, transferring it onto an image support such as paper if necessary, and then fixing it by heating, pressure, or a solvent. However, in recent years, 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-seal. However, if the softening point of the resin is simply lowered, a problem arises in that the toner particles aggregate during use, causing a blocking phenomenon. This fixation method has come to be used. The heated roller method has higher thermal efficiency than the heat fixing method, so it can fix the toner in a shorter time, but because the toner and the heated roller come into direct contact, the toner often adheres to the heated roller, which is the so-called offset phenomenon. has become a problem, and it is desired to develop a binder resin for toner that can solve this problem. Conventional binder resins include styrene-acrylic acid ester copolymers, styrene-butadiene copolymers, and styrene-acrylonitrile copolymers, but these vinyl copolymers generally have poor durability. Many have poor offset properties and fluidity. On the other hand, bisphenol type epoxy resin has a lower molecular weight than the vinyl copolymer, so
Although a toner with excellent fluidity and fixing properties can be obtained, the offset property tends to decrease because the melt viscosity of the resin is low. In response to this, various polyester resins have recently been proposed as toner binder resins that are excellent in both offset resistance and fluidity. The present inventors focused on such polyester resins and conducted extensive research to develop a new toner binder resin with excellent blocking resistance, offset resistance, and low-temperature fluidity, and as a result, they were able to complete the present invention. Ivy. That is, the present invention provides an electrophotographic toner in which a colorant is dispersed in a binder resin. The softening point obtained by reacting at least one crosslinking agent selected from the group consisting of the above polybasic acids or their anhydrides and trihydric or higher polyhydric alcohols and () dihydric alcohol is 50 to 190°C, An electrophotographic toner composition containing a rosin-based polymer compound having a glass transition point of 10 to 170°C and a number average molecular weight of 2,000 to 40,000 (excluding those that gel with xylene). relating to things. In addition, what is referred to herein as a material that gels in xylene means a material that contains a material that does not dissolve in xylene. The rosin glycidyl ester () used in the present invention can be prepared by subjecting rosin and epihalohydrin to a heating reaction in the presence of an alkaline substance such as an organic amino. Examples of the rosin used include gum rosin,
Examples include natural rosins such as uddrosin and tall oil rosin, hydrogenated rosins obtained by modifying these rosins, and disproportionated rosins. Also,
Naturally, the 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,
Examples include N-phenylmorpholine, N-methylpiperidine, and pyridine. Specific examples of onium salts of tertiary amines include tetramethylammonium chloride, tetramethylammonium bromide, benzyltriethylammonium chloride, allyltriethylammonium bromide, tetrabutylammonium chloride, methyltrioctylammonium chloride, and trimethylamine hydrochloride. Examples include triethylamine hydrochloride, pyridine hydrochloride, and the like. The dicarboxylic acids or dicarboxylic acid anhydrides (hereinafter simply referred to as dicarboxylic acids) used in the present invention include orthophthalic acid, isophthalic acid, terephthalic acid, endomethylenetetrahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid. , hexahydrophthalic acid, methylhexahydrophthalic acid, maleic acid,
Examples include fumaric acid, succinic acid, adipic acid, azelaic acid, sebacic acid, alkenylsuccinic acids having 8 to 18 carbon atoms, alkylsuccinic acids having 8 to 18 carbon atoms, and acid anhydrides thereof. Examples of the crosslinking agent () used in the present invention include the following compounds. Examples of the polyfunctional epoxy compound include an epoxy resin which is a condensation product of bisphenol A and epihalohydrin, and rosin diepoxide or rosin triepoxide which is a reaction product of acrylated rosin or fumarated rosin and epihalohydrin. The rosin used for the polyepoxide of the rosin is the same as that used for the rosin glycidyl ester. Examples of trivalent or higher polybasic acids or their anhydrides include trimellitic acid, pyromellitic acid, and acid anhydrides corresponding to these. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. The dihydric alcohol is used to adjust the glass transition point of the rosin-based polymer compound obtained by reacting the other components (), (), and (), and to improve the low-temperature fixability. The dihydric alcohol () used in the present invention is not particularly limited, and includes, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,2-butanediol, 1,3
-butanediol, 1,4-butanediol, bisphenol A, hydrogenated bisphenol A, ethoxylated bisphenol A, propoxylated bisphenol A, bishydroxyethyl terephthalate, and the like. The amount of dihydric alcohol to be used is appropriately determined in consideration of the glass transition point of the rosin-based polymer compound to be obtained. Usually, 1 to 1 of rosin glycidyl ester
It is used with 70 mol% replaced by dihydric alcohol. As a method for producing the rosin-based polymer compound used in the present invention, for example, rosin glycidyl ester, the dicarboxylic acids, the crosslinking agent, and the dihydric alcohol are simultaneously charged, and in the presence of the organic amines as a reaction catalyst or Method of heating reaction in the absence of rosin glycidyl ester,
heating dicarboxylic acids and dihydric alcohols in the presence or absence of organic amines,
Adding a crosslinking agent during or after the reaction,
A method of further heating the reaction to advance the reaction can be adopted. In that case, the molar ratio of rosin glycidyl ester to dicarboxylic acid used is preferably 1:1, but it can also be within the range of 1.5:1.0 to 1.0:1.5. On the other hand, the amount of the crosslinking agent to be used must be appropriately and carefully determined since it has a significant effect on the physical properties, particularly the molecular weight and molecular weight distribution, of the resulting toner binder resin. The amount of the polyfunctional epoxy compound used among the crosslinking agents may be determined by considering the number of functional groups of the compound, that is, the epoxy equivalent, and usually when the total number of moles of rosin glycidyl ester and dicarboxylic acids is 1 mole, For example, for fumarized rosin triglycidyl ester, the amount is 0.005 to 0.07 mol, preferably 0.005 to 0.04 mol. In addition, in the case of commercially available bisphenol type epoxy resins, 0.005 to 0.14 mol,
The amount is preferably 0.005 to 0.07 mol. Similarly, polyhydric carboxylic acids or polyhydric alcohols are usually used in consideration of the number of their functional groups, and in the case of trihydric acids, for example, 0.005 to 0.3 mol, preferably 0.005 to 1 mol of the total of rosin glycidyl ester and dicarboxylic acid. Use within the range of ~0.15 mol. In the present invention, it is not necessary to carry out the reaction in the presence of organic amines, but depending on the type of dicarboxylic acids used, they may be used to shorten the reaction time. It is preferably within the range of 0.01 to 5% (weight %, hereinafter the same), preferably 0.05 to 1%. In addition, in the present invention, the binder resin of the toner of the present invention can be obtained in high yield regardless of the presence or absence of a solvent during the reaction, but a solvent is used in order to smoothly distill the water produced during the reaction out of the system. It is also possible to do so. The solvent is determined in consideration of azeotropic properties with the produced water, non-reactivity with rosin glycidyl esters, dicarboxylic acids, and crosslinking agents, and specific examples include toluene and xylene. In the present invention, the reaction temperature and reaction time are appropriately determined in consideration of the yield of the product, but when an acid anhydride is used as the dicarboxylic acid, the reaction temperature is 100 to 250°C, preferably 130 to 180°C. C, 150 to 300 C, preferably 180 to 260 C when a dicarboxylic acid is used, and in either case, the reaction time is preferably 0.5 to 10 hours, preferably 1 to 8 hours. If a solvent is used during the reaction, the solid content can be obtained by distilling it off under reduced pressure. By the production method described above, the novel rosin-based polymer compound used in the present invention can be obtained in high yield. In addition, the end point of the reaction in the present invention is
It can be easily determined by suitably measuring the acid value or molecular weight of the resulting resin by gel permeation chromatography. The rosin-based polymer compound obtained in the present invention has a softening point of 50 to 190°C and a glass transition point in consideration of properties as an electrophotographic toner composition, namely blocking resistance, offset resistance, and low-temperature fluidity. is 10
Preferably, the temperature is ~170°C and the number average molecular weight is 2000-4000. That is, if the softening point is less than 50°C, the offset resistance will be poor, and if it exceeds 110°C, the low temperature fluidity will be poor. If the glass transition point is less than 10°C, the offset resistance and low temperature fluidity will be poor. If the number average molecular weight is less than 2,000, the blocking resistance and offset resistance will be poor, and if it exceeds 40,000, the low temperature fluidity will be poor. The molecular weight distribution is not particularly limited, but since it affects offset resistance and low-temperature fluidity, it is usually preferably in the range of 1.5 to 50. 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. The toner of the present invention may appropriately contain a carrier such as a magnetic substance. Examples of magnetic substances include
(i) Metal powders such as iron, manganese, nickel, cobalt and chromium; (ii) iron alloys such as ferrite and magnetite; alloys or compounds of cobalt, nickel and manganese; (iii) other conventionally known ferromagnetic materials. can be given. Next, the electrophotographic toner of the present invention will be described with reference to reference examples and examples, but the present invention is not limited to these examples. Reference example 1 (Production of disproportionated rosin glycidyl ester) 500ml 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 unsaponifiables), 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 solution using a rotary evaporator, and the solution was further heated at 2 mmHg and 120°C.
The volatile components were completely removed under the following conditions to obtain the title pale yellow oil (yield 97.2%). The acid value of this product was 0, the epoxy equivalent was 425, and the purity was 84% in terms of epoxy equivalent. Reference Examples 2 to 4 In Reference Example 1, the starting material rosin was gum rosin (purity 91%, acid value 169, softening point 75°C), hydrogenated rosin (purity 89%, acid value 165, softening point 74°C), Thor Oil rosin (purity 87%, acid value 163, softening point 73℃)
Various rosin glycidyl esters were obtained by carrying out the reaction in the same manner except that they were used in Reference Examples 2 to 4 in turn. The acid value of Reference Example 2 is 0,
The epoxy equivalent was 436.5 and the purity was 82.1%.
Reference example 3 has an acid value of 0, an epoxy equivalent of 431.6,
The purity is 83.5%, and the acid value of Reference Example 4 is 0.
The epoxy equivalent was 445.5 and the purity was 80.0%. Reference Example 5 (Manufacture of fumarized rosin triglycidyl ester) 300 g of the gum rosin used in Reference Example 2 was heated and melted at 140 to 160°C under a nitrogen stream and stirred, and then 116 g of crystalline fumaric acid was added and The temperature was raised to 220°C, and the reaction was carried out at the same temperature for 2 hours to obtain fumarized rosin. 100 g of this fumarated rosin, 500 g of epichlorohydrin and 0.1 g of benzyltrimethylammonium chloride were added and reacted at 80°C for 4 hours. Next, 28.8g of granular sodium hydroxide was added in portions.
The temperature was raised to 110°C and the reaction was carried out under reflux for 2 hours, and the produced water was removed from the system using a water separator. The precipitated common salt was filtered, and the unreacted epichlorohydrin was distilled off from the liquid under conditions of 2 mmHg and 120°C to obtain a balsam-like fumarized rosin triglycidyl ester.
This product had an acid value of 0 and an epoxy equivalent of 337. Example 1 425 g of the disproportionated rosin glycidyl ester obtained in Reference Example 1, 232.8 g of phthalic anhydride, and 86 g of triethylene glycol were charged and heated under a nitrogen stream.
The reaction was carried out at 240°C for 4 hours. After confirming that the acid value is approximately 10, add trimellitic anhydride.
14.9g was added and the reaction continued. It was confirmed by gel permeation chromatography that a predetermined molecular weight had been reached, and the reaction was terminated. The resulting resin had a softening point of 126°C, a glass transition point of 72°C, a number average molecular weight of 4350, and a molecular weight distribution of 32. Example 2 A resin was obtained by carrying out the reaction in the same manner as in Example 1, except that the types of starting materials and the amounts used were changed as shown in Table 1. The measurement results are shown in Table 1. Example 3 425 g of disproportionated rosin glycidyl ester obtained in Reference Example 2 and 114 g of bisphenol A were added.
The reaction was carried out at 180°C for 2 hours. Bisphenol A by gel permeation chromatography
After confirming that the peak had disappeared, 133.2 g of dodecenyl succinic anhydride was added and reacted at 240°C for 3 hours. After the acid value reaches approximately 10, reference example 5
18.0 g of fumarized rosin triglycidyl ester, which is the obtained crosslinking agent, was added and the reaction was continued until a predetermined molecular weight was reached to obtain a resin. Measurement results first
Shown in the table. Example 4 A resin was obtained by carrying out the reaction in the same manner as in Example 3, except that the types of starting materials and the amounts used were changed as shown in Table 1. The measurement results are shown in Table 1. Examples 5 to 8 Various resins were obtained by carrying out the reaction in the same manner as in Example 1, except that the types of starting materials and the amounts used were changed as shown in Table 1. The measurement results are shown in Table 1. Comparative Example 1 425 g of the disproportionated rosin glycidyl ester obtained in Example 1 and 148 g of phthalic anhydride were reacted at 240° C. for 4 hours in a nitrogen stream to obtain a resin. The measurement results are shown in Table 1. Comparative Example 2 Pentaerythritol ester of disproportionated rosin as natural resin-modified pentaerythritol resin (number average molecular weight 902, glass transition point 59°C, acid value 10)
was used. Comparative Example 3 Rosin-modified maleic acid resin (manufactured by Tokushima Oil Co., Ltd.,
Product name: Tescon RM1000, number average molecular weight 1430,
Acid value 21) was used. Comparative Example 4 Glycerin ester of disproportionated rosin (number average molecular weight 837,
A glass transition point of 48°C and an acid value of 14) were used. (Toner performance test method) 95 parts by weight of the resins obtained in Examples 1 to 8 and Comparative Examples 1 to 4, respectively, and 5 parts by weight of carbon black were mixed in a ball mill, kneaded using hot rolls, and then mixed in a jet pulverizer. Finely pulverized with an average particle size of 13
I got ~15 micron toner. For 5 parts by weight of this toner, 95 parts 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 and fixed using a fixing roller whose surface was made of Teflon. At this time, the fixing state was evaluated by varying the fixing roller temperature. That is, a black band-shaped copy was made and immediately peeled off with cellophane adhesive tape, and the transmittance of the tape was expressed in %. Next, in order to investigate the offset phenomenon of toner transfer to the roller, a new blank paper was brought into pressure contact with the fixing roller immediately after fixing, and the presence or absence of toner stains on the blank paper was visually determined. Evaluation of blocking property is based on the load on the toner.
The temperature at which blocking occurred was measured by observing the degree of solidification after pouring 500 g onto each sample and leaving it for 2 hours at each temperature of 50 to 65°C. The test results are shown in Table 2. In Table 2, the symbols 〇, △, and × represent offsets, and mean slightly offsets and offsets.

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Claims (1)

[Scope of Claims] 1. An electrophotographic toner comprising a colorant dispersed in a binder resin, wherein the binder resin includes () rosin glycidyl ester, () dicarboxylic acid or dicarboxylic acid anhydride, () polyfunctional epoxy compound, At least one crosslinking agent selected from the group consisting of a trivalent or higher polybasic acid or its acid anhydride and a trivalent or higher polyhydric alcohol, and () a dihydric alcohol with a softening point of 50 ~190℃, glass transition temperature 10~170℃, number average molecular weight 2000
~4000 rosin-based polymer compounds (however,
1. An electrophotographic toner composition characterized by containing a toner composition (excluding those that gel with xylene).