JPS6345099B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a toner (developing powder) for developing electrostatic latent images in electrophotography, electrostatic recording, electrostatic printing, and the like. As is well known, in a recording method such as electrophotography in which a visible image is electrostatically formed on copy paper, the entire surface of the photoconductive insulating layer is charged by corona discharge, etc. Then, the electrostatic charge in the exposed area is discharged and an electrostatic latent image with a predetermined image pattern is generated. After that, developing powder consisting of pigment and binder resin, generally called toner, is attached to the latent image. The powder image is transferred to paper, film, etc., and fixed by heating or solvent vapor to obtain an image. In the above-mentioned electrostatic visible image forming method, fixing of the toner image is important, and especially for modern high-speed copying machines, it is necessary to
A toner that can be heat-fixed at high speed is required. Toners using binder resins with relatively low melting points are
Although it satisfies the requirements for high-speed heat fixing to some extent, the adhesiveness of the toner increases and the toner adheres to the carrier and photoconductive insulating layer, causing image deterioration such as "fogging" and "reduced image density." Moreover, mutual blocking of toner particles tends to occur. Therefore, it is desirable that the resin has a high melting point and a low melt viscosity to the extent that no crimping or blocking occurs. Conventionally, epoxy resins, polyester resins, styrene resins, styrene-acrylic ester copolymers, and blends of these resins have been used as such binder resins, but even these resins still have low melting points. The above relationship between and melt viscosity is not fully satisfied. That is, when trying to obtain a desired melt viscosity, for example, the melting point of epoxy resin, 43.degree. C., is too low, resulting in fusion to the carrier and photoconductive insulating layer and blocking between toner particles in summer. Accordingly, an object of the present invention is to provide a binder resin for toner having a relatively high melting point or relatively high adhesion temperature and a low melt viscosity. A further object of the present invention is to provide a toner comprising a binder resin, a colorant, and, if necessary, a charge sign control agent, which has excellent high-speed fixing properties and storage stability. The object of the present invention is to provide a toner for developing electrostatic latent images which contains a binder resin and a colorant as essential components, and optionally a charge sign control agent dye, as a binder resin of the general formula (). In the formula, A is -CH ₂ -,

[Formula] or -SO ₂ - group; R is a hydrogen atom or a methyl group; R ₁ and R ₂ may be the same or different and are each a hydrogen atom or an alkyl group; X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ , X ₇ and X ₈ may be the same or different and are each _a hydrogen atom or _a halogen atom; The following groups may be different, including: (2) Hydrogen atom (-H) However, in the above formulas (1) to (4), the definition of R is the same as above, and either Y ₁ or Y ₂ represents a hydroxyl group, and the other represents a chlorine atom or a bromine atom. or an atomic group; n represents the average degree of polymerization and is a number from 0 to 10, and at least 90% of all terminal groups (total of T ₁ and T ₂ ) are the following α-glycol groups. This is achieved by the toner of the present invention, which is characterized by using an α-glycol resin. Among the α-glycol resins used as the binder resin of the toner in the present invention, those in which n is greater than 0 include 1.1 to 2.5 moles of epihalohydrin and 2,2-bis(4-hydroxyphenyl)propane [commonly known as Bisphenol A] or 2,2-bis(4-hydroxyphenyl)methane and 4 moles or more of water per mole of epihalohydrin are reacted in advance in the presence of a catalyst such as tetramethylammonium bromide. (1st step) and then reacting the resulting reaction product with an alkali metal hydroxide such as NaOH or KOH (2nd step). Details of the manufacturing method can be found in Japanese Patent Application No. 1973-
68926. The above reaction is shown, for example, by the following reaction formula. (In the above formula,

【ceremony,

[Formula] shows that it is symmetrical with the axis of symmetry. ) The α-glycol resin obtained by the above method is a mixture of reaction products with various degrees of polymerization,
Furthermore, as a by-product, at the end of the molecule

instead of [expression]

【formula】

[Formula] or

containing reaction products having the formula

[Formula] occupies 90%, preferably 98% or more of all terminal groups,

[Formula] or

[Formula] and other terminal groups are present in trace amounts,

[Formula] The terminal group is on the order of several percent. Further, in the general formula (), a preferable example of a compound where n is 0 is the following general formula (') (In the formula, R represents the same meaning as above.) These compounds are represented by the following general formula () (In the formula, R represents the same meaning as above.) To the bisphenol compound represented by the following formula () (In the formula, X represents a halogen atom) It can be produced by reacting a glycerin monohalohydrin compound represented by the following in the presence of an alkali catalyst. Preferred examples of the compound of formula () used in the production of the compound of formula (') above are 4,4'-dihydroxydiphenyl-2,2-propane, and 4,4'-dihydroxydiphenyl-2,2-propane.
4'-dihydroxydiphenylmethane and the like. Further, in a preferable compound of the formula (), X is a chlorine atom, that is, glycerin-α-monochlorohydrin, glycerin-β-monochlorohydrin, or a mixture thereof. The compound of formula (') can be prepared by mixing bisphenols of formula () and glycerin monohalohydrins of formula () at 50 to 200°C in the presence of an alkali catalyst.
Preferably at a temperature in the range of 60 to 200°C, more preferably 80 to 120°C for 10 minutes to 5 hours, preferably 20 minutes to 5 hours.
It can be conveniently produced by reacting for a period of time. The ratio of the bisphenols and the glycerin monohalohydrin compound to be used is preferably 1 equivalent or more, preferably 1.0 to 1.5 equivalents, based on the phenolic hydroxyl group of the bisphenols. Catalysts that can be used include hydroxides of Group A or Group A metals, such as caustic alkalis such as sodium hydroxide or potassium hydroxide, and calcium hydroxide, or substances whose aqueous solutions are alkaline, such as those mentioned above or other than those mentioned above. Examples include metal carbonates, secondary phosphates, orthophosphates, and silicates. Among these, metal hydroxides are preferred, and the amount used is as low as that of glycerol monohalohydrin. A suitable amount is 1 equivalent or more, preferably 1.00 to 1.50 equivalents, based on the compound. Any of the α-glycol resins described above can be used as the binder resin of the toner of the present invention, including a resin in which n is 0 in the general formula () or a resin in which n is 3 to 6. is preferred. Further, the above-mentioned α-glycol resin can be used alone as a binder resin in the toner of the present invention, but
Depending on the specifications of the copier used, other known toner resins may be used to prevent fogging caused by toner wear and toner slow-off, or to prevent offset caused by toner adhesion to the roll. , can be used together in an amount of 90% by weight or less based on the total amount of the binder resin used. in this case,
An appropriate α-glycol resin is selected from among those with n=0 to 10 depending on the other resin to be used together. By appropriately selecting a combination of the α-glycol resin and the resin used in combination, the dispersion of the charge sign control agent dye can be improved. Known toner resins that can be used in combination with these include, for example, styrene resins, styrene-methacrylate copolymers, polyester resins, polycarbonate resins, rosin-modified maleic acid alkylene resins, xylene resins, polyvinyl butyral resins, phenol resins, Examples include resins having a glass transition temperature of 40°C or higher, such as Sierrak resin. Coloring agents include pigments such as carbon black, Sudan black, phthalocyanine blue, Orazole Red G, and Neo Pomelo Yellow.
A dye such as GR is used in an amount of 1 to 20% by weight in the toner. The particle size of toner is generally 5 to 35 microns. Examples of charge sign control dyes include Morgan A, nigrosine SSB, and pomelo black dye. The toner of the present invention is produced by melting a powdered α-glycol resin, blending a colorant and, if necessary, a charge sign control agent therewith on a heated composite roll, mixing with the roll, and cooling. It can be conveniently manufactured by grinding to ~35μ. However, it can also be produced by mixing the required components by any other known mixing means. This toner is used in combination with a carrier such as NaCl, glass powder, or iron powder. α- used as a binder resin in the toner of the present invention
Glycol resin has a similar chemical structure to epoxy resin, which is currently widely used as a binder resin for toner, but compared to epoxy resin, it has many hydroxyl groups and molecules are bonded together through strong hydrogen bonds. Because of this, it exhibits a higher glass transition temperature than epoxy resins of the same molecular weight. In other words, at the same glass transition temperature, it has a lower molecular weight and lower melt viscosity than epoxy resin, making it suitable as a binder resin for toners for high-speed copying machines. In particular, in the general formula (), when n=0 and R=-
α-glycol resin, which is CH ₃ , has a melting point of 97℃
It has a sufficient melting point and low melt viscosity as a binder resin for toner, but the corresponding melting point of epoxy resin is 43°C, making it unsuitable as a binder resin for toner because it causes blocking in the summer. be. As mentioned above, the α-glycol resin used in the toner of the present invention has many hydroxyl groups in the molecule, so once the toner is melted and fixed, it adheres very firmly to the paper due to hydrogen bonds, and the characters and graphics on the copy are It has the advantage that it does not peel off and make the copy difficult to see. The α-glycol resin also has a high melting point and is crystalline, so the toner cools quickly after being crimped.
The transfer process is about 100% faster than toner using epoxy resin.
It also has the advantage of being 20-30% faster. The present invention will be explained in more detail with reference to Examples below. The methods for measuring various physical property values shown in the examples are as follows:
It is as follows. (1) Number average molecular weight (n) Measured by vapor pressure osmosis using methyl ethyl ketone as a solvent using Hitachi Molecular Weight Analyzer Model 115. (2) Glass transition temperature (Tg) Perkin Elmer differential scanning calorimeter model DSC−
Measured from the inflection point of specific heat using 1B. (3) Softening point (Ts) Measured by the ring and ball method in accordance with JIS K-2531. (4) Melt viscosity Measured using a rotating cylinder viscometer Iwamoto rheometer. Reference example 1 Production of α-glycol resin with an average n of 4.3 2,
2-bis(4-hydroxyphenyl)propane
100 parts by weight, 45 parts by weight of epichlorohydrin, 44 parts by weight of glycerin monochlorohydrin, and 140 parts by weight of water were placed in a 10 stainless steel reactor and mixed with stirring. The product was heated to 100°C, and 159 parts by weight of a 25% by weight NaOH aqueous solution was added to this mixture while keeping it at the same temperature.
The mixture was added over a period of 1 minute, and stirring was continued at the same temperature for an additional 35 minutes. Then add methyl isobutyl ketone to the reaction mixture.
330 parts by weight was added and thoroughly stirred to dissolve at 120°C. After the resulting mixture was allowed to stand still, the lower aqueous layer was separated and removed. The upper methyl isobutyl ketone layer was further washed twice with warm water, and then the methyl isobutyl ketone was distilled off to obtain 139 parts by weight of α-glycol resin. The number average molecular weight (n), glass transition point (Tg), and softening point (Ts) of the obtained α-glycol resin are set to approximately the same Tg as this α-glycol resin.
Table 1 shows a comparison between an epoxy resin (trade name Epicoat 2057GP manufactured by Shell Chemical) and a styrene resin (trade name Picolastek D-125 manufactured by Esso Standard Sekiyu Co., Ltd.), which are binder resins for toners. Furthermore, the melt viscosity-temperature relationship of each of these resins is shown in the attached drawings. In the figures, curve 1 is the melt viscosity-temperature curve of the α-glycol resin of the present invention, curve 2 is Epicote 2057GP, and curve 3 is Copila Stick 125D.

[Table] Reference Example 2 Production of α-glycol resin with n=0 100 parts by weight of 2,2-bis(4-hydroxyphenyl)propane, 107 parts by weight of glycerin-α-monochlorohydrin, and 140 parts by weight of water. The mixture was placed in a stainless steel reactor and stirred and mixed. the product
While heating to 100° C. and maintaining the same temperature, 174 parts by weight of a 25% by weight NaOH aqueous solution was added to this mixture over 15 minutes, and stirring was continued at the same temperature for an additional 35 minutes. Next, 400 parts by weight of methyl isobutyl ketone was added to the reaction mixture, thoroughly stirred, and dissolved at 140°C. After the resulting mixture was left to stand, the lower aqueous layer was separated and removed.
After washing the upper methyl ethyl ketone layer twice with warm water, the methyl ethyl ketone was distilled off.
120 parts by weight of white crystals were obtained. The crystals were mixed with methyl ethyl ketone/methyl isobutyl ketone = 1/1.
When recrystallized with 240 parts by weight of mixed solvent (weight ratio),
105 parts by weight of white crystals, which is a compound having a melting point of 97° C. and in which n=0 in the formula from mass spectra, NMR spectra, and infrared spectra, was obtained. Mass spectrum; M ⁺ 376 358 (M ⁺ −18)

【formula】

[Table] ｜
_CH3
Infrared spectrum: 3350cm ^-1 , 1600cm ^-1 , 1240cm
^-1 , 1040 cm ^-1 , etc. Example 1 100 parts by weight of the α-glycol resin obtained in Reference Example 1 with an average n of 4.3 and a molecular weight of 1600, and 6 parts by weight of carbon black (trade name MA-100, manufactured by Mitsubishi Chemical Corporation). of
The mixture was melted and kneaded at 130 to 150°C, and after cooling, it was pulverized in a jet mill, and classified to 5 to 20μ in a microplex (rotating wall type wind classifier manufactured by ALPINE) to obtain a toner for an electrostatic copying machine. . The obtained toner,
Mixed with iron powder of 200-300 yen, about 2
A developer containing a weight percent toner is obtained. A positive latent image on the selenium photosensitive plate was developed with this developer to obtain a positive mirror image. This developed toner was electrostatically transferred onto high-quality paper and then fixed using a pressure roll press fixing device heated to 140° C., yielding a clear copy. When the surface and cross section of the resulting copy were observed under a microscope, it was found that the toner particles had melted together and penetrated into the network structure of the paper. Also, put sellotape (1cm x 5cm) on the solid black part of this copy, and
Kg roll is rolled and crucified, then 5
When the adhesiveness was examined by peeling at a rate of mm/sec, almost no toner was observed to adhere to the cellophane tape. Example 2 40 parts by weight of α-glycol resin obtained in Reference Example 1 with an average n of 4.3 and a molecular weight of 1600, 60 parts by weight of styrene-methacrylic acid-n-butyl ester copolymer (trade name: Higher SBM-73 manufactured by Sanyo Chemical Co., Ltd.) Department, Morgan
10 parts by weight of A and 2.5 parts by weight of Nigrosine SSB dye,
The toner is melted and kneaded at 140 to 160°C, and after cooling, it is finely pulverized in a jet mill and classified into 5 to 20 micron particles in a microplex to obtain toner for electrostatic copying machines. A developer was obtained by mixing with iron powder from Tsushiyu. A negative latent image on the zinc oxide photosensitive paper was developed with this developer to obtain a positive image. After electrostatically transferring this developed image toner to high-quality paper, Example 1
After fixing in the same manner as above, microscopic observation and adhesion test using Sellotape revealed that the toner had a clumpy structure (the toner particles did not fully melt each other and had an unevenly fused particle structure), but they adhered well and were fused together. It had penetrated the network structure of the paper. Also, in the adhesion test, almost no adhesion to cellophane tape was observed. Example 3 α-glycol resin with n=0 obtained in Reference Example 2
Melt and knead 6 parts by weight of 100 weight carbon black (trade name: MA-100 manufactured by Mitsubishi Chemical Corporation) at 100 to 110°C,
After cooling, the mixture was pulverized using a jet mill and classified to 5 to 20 microns using a microplex to obtain a toner for electrostatic copying machines. Using the obtained toner, a positive mirror image was obtained in the same manner as in Example 1, and this developed toner was electrostatically transferred onto high-quality paper, and then fixed using a pressure roll fixing device heated to 110°C, resulting in a clear copy. It was done. When this obtained copy was observed under a microscope and subjected to an adhesion test with cellophane tape in the same manner as in Example 1, it was found that the toner particles melted together and sufficiently penetrated into the network structure of the paper. Almost no toner adhesion was observed. Comparative Example Two types of toners having the following compositions A and B were obtained in the same manner as in Example 2, except that Picola Stick D125 and Epicoat 2057GP were used instead of the α-glycol resin. A Picola Stick D125 Morgan A Nigrosine SSB dye 100 parts by weight 10 〃 2.5 〃 and B Epicoat 2057GP Morgan A Nigrosine SSB dye 100 parts by weight 10 〃 2.5 〃 Regarding copies obtained in the same manner as in Example 2 using these toners. , Place A where the same microscope observation and cellophane adhesion test as in Example 1 were performed.
In the case of copying using this method, the toner particles did not melt together sufficiently and had a clumpy structure, and no intrusion into the network structure of the paper was observed, and most of the toner particles adhered to the cellophane tape. In addition, the copy using B had good adhesion between particles and had a smooth structure, but there was little penetration into the network structure of the paper and it adhered to the cellophane tape considerably.

[Brief explanation of the drawing]

The accompanying drawings are graphs showing melt viscosity-temperature curves of one example of the α-glycol resin used in the toner of the present invention and a control resin. The meanings of the symbols in the figure are as follows.
1...α-glycol resin of the present invention (n=4.3)
Melt viscosity-temperature curve of 2... Control Epicote
Melt viscosity-temperature curve of 2057GP, 3... Melt viscosity-temperature curve of control Picolastic 125D.

Claims (1)

[Claims] 1. In a toner for developing an electrostatic latent image containing a binder resin and a colorant, the binder resin has the general formula In the formula, A is -CH ₂ -, [Formula] or -SO ₂ - group; R is a hydrogen atom or a methyl group; R ₁ and R ₂ may be the same or different, and each is a hydrogen atom or an alkyl group. and X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ , X ₇ and X ₈ may be the same or different and each is a hydrogen atom or a halogen atom; T ₁ and T ₂ represents a terminal group, which may be the same or different and substantially of the following groups: (2) Hydrogen atom (-H), However, in the above formulas (1) to (4), the definition of R is the same as above, and either Y ₁ or Y ₂ represents a hydroxyl group, and the other represents a chlorine atom or a bromine atom. or an atomic group; n represents the average degree of polymerization and is a number from 0 to 10;
Total end groups of glycol resin (sum of T ₁ and T ₂ )
At least 90% of the following α-glycol groups An electrostatic latent image developing toner characterized by: 2. The toner according to claim 1, further comprising a charge sign control agent pigment dispersed therein.