JPH0814714B2 - Powder type toner for thermosetting electrostatic image development - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a toner for dry-developing an electrostatic image such as electrophotography, and more specifically, a heat-resistant substrate such as metal or glass. The present invention relates to a thermosetting powder toner for developing electrostatic image useful for.

(Prior Art) Conventionally, as a dry development method, a method of using a two-component developer in which toner particles are mixed with carrier particles, that is, glass beads or magnetic powder, and a method of imparting magnetism to the toner particles themselves is used. There is a method of using a component type toner, and more recently, a method of using a non-magnetic single component type toner excellent in environment resistance has been proposed.

Generally, in the electrophotographic method, an electrostatic charge image on an electrophotographic photosensitive member is developed with a toner, transferred to a substrate, heated by a heat fixing roller, and the toner is fused and fixed. Therefore, the conventional binder resin for toner is thermoplastic. JP-B-51-23354 discloses a technique of using a resin obtained by polymerizing and cross-linking styrene-acrylic ester together with divinylbenzene, and JP-B-52-25420 contains a trifunctional or higher functional polyol. It is disclosed that a so-called cross-linked polyester resin is used as a binder for toner. However, these resins are intended to improve the offset phenomenon when fixing the toner, and such cross-linking resins are basically thermoplastic.

Recently, electrophotography has been applied to heat-resistant substrates such as metal and glass to produce images with excellent physical and chemical resistance such as heat resistance, water resistance, chemical resistance, scratch resistance, and workability. There is an attempt to form. However, especially in metal applications, undercoating, white coating, printing, and topcoating are generally applied as necessary, and an image having excellent resistance is formed under baking conditions of 100 ° C to 250 ° C for 5 minutes to several tens of minutes. There is. Therefore, it is impossible to satisfy the above requirements even if the conventional toner containing the thermoplastic resin as a binder is used for such an application.

Further, Japanese Patent Laid-Open No. 52-6535 discloses a photoconductive toner using a binder resin having a curable functional group, but this does not develop an electrostatic charge image but an aluminum plate or the like. Toner is evenly dispersed on the surface of the exposed part, and imagewise exposure is performed after corona discharge to remove the toner in the exposed area, which causes a problem in copying speed.

JP-A-54-8532 discloses a liquid developing toner in which a thermosetting resin containing a curing agent and a colorant are dispersed in a carrier liquid, and an epoxy resin having a molecular weight of about 350 is used. ing. However, according to the research conducted by the inventors of the present invention, when it is applied to metals and the like, there are problems in workability and the like and it cannot be put to practical use. In addition,
Japanese Patent Laid-Open No. 58-68753 discloses a capsule toner in which a curable substance is used as a core substance and a curing agent is provided in an outer shell.
However, this is intended as a pressure fixing toner. These are intended for good fixing to paper, for example, improvement in rubbing resistance with an eraser, and not for imparting various resistances after application to metal or the like.

(Problems to be Solved by the Invention) The present invention satisfies the above requirements, and in particular, a thermosetting electrostatic image developing powder having excellent adhesiveness to an undercoat layer, a white coat or a top coat layer. A body toner is provided.

[Structure of Invention]

(Means for Solving the Problems) The present invention has a room temperature solid bisphenol A type having one or more epoxy groups in one molecule, a melting point of 40 ° C. or more, and a number average molecular weight of 800 to 4000. Alternatively, the present invention provides a thermosetting type electrostatic toner image developing powder toner obtained by melt-mixing a bisphenol F type epoxy resin, a cross-linking agent, a colorant, a charge control agent and other necessary additives, pulverizing and classifying. .

The epoxy resin used in the present invention includes 1
It is a bisphenol A type or bisphenol F type epoxy resin which has one or more epoxy groups in the molecule, has a melting point of 40 ° C. or higher, and has a number average molecular weight of 800 to 4000 and is solid at room temperature. By using the epoxy resin having such requirements, it is possible to obtain an image that withstands the above-mentioned various requirements after heat curing. Specific examples are Epicoat 1001,1002,1004,1007,1009,2002 manufactured by Shell Chemical Co., Ltd. and YDF-2004,2007 manufactured by Tohto Kasei Co., Ltd. These are acetic acid, butyric acid, oleic acid, benzoic acid, acrylic acid. , Methacrylic acid, linseed oil, castor oil, or the like, which is partially esterified with a fatty acid can be used. When the number average molecular weight is 800 or less, the obtained image becomes brittle, and the chemical resistance and workability are poor. When the number average molecular weight is 4000 or more, the hardness is insufficient and scratch resistance becomes a problem. If the melting point is less than 40 ° C, it is difficult to put the powder toner into practical use in terms of blocking. The melting point is 40 ° C to 200 ° C, preferably 50 ° C to 100 ° C.

The cross-linking agent is selected from those which do not substantially react with the epoxy resin during the production and storage of the toner of the present invention, but which react and cure under the above-mentioned baking conditions. Specific examples include polycarboxylic acids or their anhydrides, amino resins, urea resins, amino compounds, and phenol resins.

Examples of the polycarboxylic acid include trimellitic acid, pyromellitic acid, tetrahydrophthalic acid, adipic acid, sebacic acid, and the like, and examples of the amino compound include:
Examples include dicyandiamide, imidazole or imidazoline and their derivatives.

Further, a part of the epoxy resin in the present invention may be replaced with a thermosetting acrylic resin and / or polyester resin, and a curing agent for these resins may be used if necessary. For example, blocked isocyanate may be used together as the curing agent. Examples of the block isocyanate include ε-caprolactam block isophorone diisocyanate, cresol block xylylene diisocyanate, and phenol block tolylene diisocyanate.

Examples of colorants include zinc yellow, yellow iron oxide, fast yellow, disazo yellow, red iron oxide, and watchchan red Ca.
Salt, Watchchan Red Ba salt, Phthalocyanine blue,
Various pigments such as metal-free phthalocyanine, quinacridone red, titanium oxide, and carbon black are appropriately selected according to the purpose from the viewpoint of hue and resistance.

The charge control agents are known per se, and include, for example, Fettschwarz HBN, Nigrosine base, Brilliant Spirit, Zapon Schwarz X, Ceres Schwarz RG, copper phthalocyanine dye, and metal-containing dye.
CI Solvent Black 1,2,3,5,7, CI Acid Black 123,22,23,28,42,43, Oil Black (CI26150),
Dyes such as spirone black, quaternary ammonium salts,
Examples include naphthenic acid metal salts, fatty acid or resin acid metal soaps.

When using a one-component toner, magnetic powder is used. As the magnetic powder, various known ferrite, magnetite, hematite and other iron, zinc, cobalt, nickel, manganese and other alloys or compounds can be used. These magnetic powders can be classified according to the purpose. It may be one that has been subjected to a surface treatment known per se, such as a hydrophobic treatment or a silane coupling agent treatment.

Other additives include fluidity improvers such as hydrophobic silica, zinc stearate, cleaning improvers such as particulate polyvinylidene fluoride, tin oxide, and charge control agents such as particulate polymethacrylic acid ester. It can be added depending on the purpose.

In the present invention, the particle size of the toner is such that the average particle size is in the range of 1 to 25 μm, and it is preferable that toner particles of 0.5 μm or less and 25 μm or more are not substantially contained. 0.5 μm
When the amount of toner having the following particle diameters increases, the fluidity deteriorates and scumming occurs. Also, when the amount of toner of 25 μm or more increases, the image becomes discolored and the commercial value decreases.

The method for producing the toner of the present invention is not particularly limited, but usually, each component is premixed by a Henschel mixer, melted / mixed / extruded by a twin-screw extruder, cooled, then coarsely crushed, crushed, and classified. To obtain a toner having an average particle diameter as described above.

The present invention will be described below by way of specific examples. The middle part in the examples indicates parts by weight.

Example 1 Epoxy resin 100 parts (Epicoat 1004, number average molecular weight 1400, epoxy equivalent 90
0 to 1000, melting point 96 to 104 ° C) Curing agent 5 parts (P108, trade name by Shell Chemical Co., mixture of tertiary amine and dicyandiamide) Carbon black 7 parts (# 44, trade name by Mitsubishi Kasei) Charge Control agent 3 parts (Nigrosine Base EX, trade name manufactured by Orient Chemical Co., Ltd.) Premix the above components with a Henschel mixer, melt / mix / extrude with a twin-screw extruder, and after cooling, crush, crush, classify and average particle size 8.8 μm toner was obtained. 0.4% by weight of hydrophobic silica RA-200H (trade name, manufactured by Degussa)
Externally processed.

Example 2 Epoxy resin 50 parts (Epicoat 2002, number average molecular weight 1200, epoxy equivalent 67
5 to 960, melting point 85 ℃) Polyester curing agent 40 parts (Curiquat 314, UCB product name, acid value 70) Carbon black 7 parts Charge control agent 3 parts (Spiron Black TRH, Hodogaya Chemical Co., Ltd. product) Using the same components as in Example 1, except that the average particle size was 9.2 μm.
Toner was obtained. 0.4% by weight of hydrophobic silica R-972 (trade name, manufactured by Degussa) was externally added to this.

Example 3 Epoxy resin 87 parts (Epicoat 1009, number average molecular weight 3750, epoxy equivalent 24
00-3500, melting point 149 ° C) Curing agent (P108) 5 parts Phthalocyanine blue 5 parts Charge control agent 3 parts (Bontron N-04, trade name manufactured by Orient Chemical Co., Ltd.) Diameter 9.0 μm
Toner was obtained. 0.4% by weight of hydrophobic silica RA-200H was externally added to this.

Example 4 A toner was obtained in the same manner as in Example 1 except that 100 parts of the epoxy resin was replaced with 70 parts, and titanium white was used as the colorant instead of carbon black, and the toner was subjected to the same external additive treatment.

Comparative Example 1 In Example 1, Epicoat 1004 (epoxy resin)
Instead of using Epicoat 828 (number average molecular weight 356, epoxy equivalent 182 to 194, melting point 40 ° C. or less), the same operation was performed, but the powder toner was not obtained.

Comparative Example 2 In Example 1, the epoxy resin was used without using a curing agent.
A toner was obtained in the same manner except that 85 parts were changed to 90 parts, and the same external addition treatment was performed.

Toner characteristics test was performed by modifying Toshiba BD-7720 copier to form an electrostatic charge image on the photoconductor and developing with the above-mentioned various toners. Transfer was performed by applying an electric charge, and then heated in an oven at 180 ° C for 30 minutes for thermosetting. The test results of the cured image are shown in Table 1.

The test method is as follows.

[Retort resistance] After retort treatment at 120 ° C for 90 minutes, test for whitening of the surface, occurrence of blisters and blisters, and no change in adhesion before and after treatment. ○ indicates no problem in practical use. × is not practical.

[Coating hardness] Pencil hardness at 25 ° C and 80 ° C.

[Workability] A cap with a depth of 3 cm is punched out with the coating on the outside, and the peeling and cracking of the coating are evaluated.
○ indicates no problem in practical use. × is not practical.

[Wet varnishing property] A solvent type clear varnish is applied on the toner image and the state of bleeding and color loss is evaluated. ○ indicates no problem in practical use. × is not practical.

[Adhesiveness] An eye-catching test using adhesive tape.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akira Ikeda 2-3-3 Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd. Yoshio Sugano (56) Reference JP 62-67562 (JP, A) JP 55-4042 (JP, A) JP 61-113069 (JP, A) WO 88/3545 (WO, A)

Claims (2)

[Claims] 1. Having one or more epoxy groups in one molecule,
A bisphenol A type or bisphenol F type epoxy resin having a melting point of 40 ° C or higher and a number average molecular weight of 800 to 4000, a cross-linking agent, a colorant, a charge control agent and other necessary additives are melt mixed, crushed and classified. A thermosetting electrostatic powder image developing toner. 2. A cross-linking agent comprising one or more selected from amino compounds, polycarboxylic acids or their anhydrides, amino resins and phenol resins. The powder toner according to the item.