KR100453045B1 - Liquid composition for developing latent electrostatic images - Google Patents

Abstract

The present invention relates to an environmentally friendly, short manufacturing process and simple wet developer.

The present invention relates to a paraffinic hydrocarbon solvent as a carrier, a ketone organic solvent having a boiling point of 110 ° C or higher as a cosolvent, a binder resin, a glass transition temperature of 40 ° C to 70 ° C, an acid-treated ethylene vinyl acetate resin, a pigment, a dispersant, a charge control agent. It provides a wet developer, characterized in that it comprises a.

The wet developer according to the present invention is environmentally friendly because it does not use an aromatic co-solvent, and is manufactured for a short time at low temperature of 40 to 60 ° C. There is an advantage that can use an easy unit war OPC.

Description

Liquid composition for developing latent electrostatic images

The present invention relates to a wet developer, and more particularly, to a wet developer that is environmentally friendly and suitable for incidental OPC.

The carrier, which occupies the largest portion of the wet developer, acts as a medium for the electrophoresis of the toner particles, and the binder resin acts to fix colored pigments in media such as paper. As other additives used, the charge control agent charges the particles of the toner, and a dispersant is used to improve the dispersibility of the toner particles. Aromatic solvents such as toluene are generally used as cosolvents, which helps the thermoplastic resin to be more easily dissolved at lower temperatures.

The wet developer consists of about 80% carrier, 15% binder, 3% pigment, and other additives. When prepared using a commercially available thermoplastic resin as a binder, it is generally difficult to dissolve the thermoplastic resin in a paraffinic hydrocarbon solvent. Therefore, in the case of producing a wet developer by dissolving a thermoplastic resin, the resin is dissolved in a carrier using a co-solvent and then cooled again to precipitate a resin using a difference in solubility according to temperature, and to disperse and coat the pigment. This is used. The carrier is then replaced with a pure hydrocarbon solvent to remove the cosolvent, followed by charging with the addition of a charge control agent (CCA).

US Patent No. 58,76896 discloses a method of using toluene as a cosolvent in the manufacture of a developer, as shown in FIG. 1, but aromatic compounds such as toluene, which are used as cosolvents, are known to be harmful to humans. Therefore, there is a disadvantage that the manufacturing method using the same is not environmentally friendly. In addition, US Patent No. US6108513, as shown in Figure 2 is a phenomenon of mixing the resin and the carrier at a high temperature of 150 ℃ or more without using a co-solvent, and then put a pigment and other additives, such as a milling process for more than one day Although the manufacturing method of the agent is disclosed, the method of mixing at a high temperature and undergoing long milling is complicated and has a disadvantage in that the manufacturing cost increases.

Accordingly, the technical problem to be achieved by the present invention is to provide a wet developer that is environmentally friendly and has a simple manufacturing process by overcoming the problems of the prior art.

1 is a schematic diagram of a method for producing a developer according to the prior art.

Figure 2 is a schematic diagram of a manufacturing method of a developer according to another prior art.

3 is a schematic view of a method for producing a developer according to the present invention.

The present invention provides a paraffinic hydrocarbon solvent as a carrier, a ketone organic solvent having a boiling point of 110 ° C. or more as a carrier, a glass transition temperature of 40 ° C. to 70 ° C. as a binder resin, and an acid-treated ethylene vinyl acetate resin. And it provides a wet developer comprising a pigment, a dispersant, a charge control agent.

According to one embodiment of the present invention, the paraffinic hydrocarbon solvent group Isopar G, Isopar H, Isopar K, Isopar L, Isopar M, Isopar V, Norpar 12, Norpar 13, Norpar 15, Isodecane and IP solvent 1620 It is preferred that any one selected from.

In addition, the ketone organic solvent is methyl isobutyl ketone, 4-methyl-2-pentanone, 2-methyl-3-hexanone, 5-methyl-2-hexanone and 5-methyl-3-hexen-2-one It is preferably any one selected from the group consisting of.

In addition, it is preferable that the mass ratio of the said mixed solvent is 6: 4-8: 2.

According to one embodiment of the invention the pigment is preferably selected from the group consisting of sunfast magenta, sunfast blue, benzidine yellow, quinacridone, carbon black and perylene green.

According to another embodiment of the present invention, the dispersant is preferably an acrylate copolymer or an amine compound.

In addition, the charge control agent is preferably any one selected from the group consisting of lecithin, basic barium petronate, calcium petronate or a combination thereof.

Hereinafter, the present invention will be described in more detail.

As shown in FIG. 3, first, methyl isobutyl ketone (MIBK), which is a carrier and a cosolvent, is mixed at a mass ratio of 6: 4 to 8: 2. If it is out of the mass ratio, it is not preferable because solubility is not appropriate and particles of a desired size cannot be obtained. At this time, the co-solvent should have boiling point of 110 ℃ or higher to prevent volatilization due to high temperature during milling, and other methyl ketone solvents having boiling point of 110 ℃ or higher besides methyl isobutyl ketone. 4-methyl-2-pentanone, 2-methyl-3 -Hexanone, 5-methyl-2-hexanone, 5-methyl-3-hexene-2-temperature can be used. Resin, pigment and dispersant are added thereto and dissolved and dispersed using Dispermat (VMA GETZMANN). The carrier uses a paraffinic hydrocarbon solvent, and an acid treated ethylene vinyl acetate resin is used as the resin. An example thereof is Elvax (manufactured by Dupont), and the glass transition temperature is 40 ℃ to 70 ℃ characterized in that. In the case of pigments, for example, yellow, Hansa brilliant (PY74, Clariant), magenta is Permanent Rubine F6B (PR184, Clariant), cyan is PB15: 4 (Sun Chemical), Finally, black uses monarch 120 (carbon black, cabot). As the dispersant, an acrylate copolymer or an amine compound is used. Examples of the acrylate copolymer are Disperbyk 116 (manufactured by BYK chemie) and the amine compound is a solsperse series (manufactured by Avecia). These materials and glass beads (0.5 mm) are placed in a container and the resin is dissolved and dispersed using Dispermat for 1 to 2 hours at about 40 to 60 ℃. Next, when the mixture is cooled while stirring at room temperature for about 2-3 hours, toner particles having an average volume of about 4 μm can be obtained due to the difference in solubility with temperature. After removing the ketone co-solvent through the filtering process in the toner particle dispersion solution thus obtained and replacing it with a pure paraffinic hydrocarbon solvent, a basic barium petronate, a kind of alkylate aryl sulfonate, was used as a charge control agent. Production) and a dispersant further, a negatively charged ancillary wet developer can be obtained. The negatively charged wet developer according to the present invention is characterized by a combination of a binder resin and a charge control agent used in the present invention, and by using such negatively charged toner, it is possible to use negatively charged OPC, which is easier to manufacture than positively charged OPC. There is this. In addition, the toner particles prepared in this way have a small amount of resin particles because most of the surface is wrapped with resin particles, and the particle distribution is narrow and symmetrical because the coating on the pigment of the resin is made by precipitation by crystallization. It has a characteristic. That is, it has excellent size distribution characteristics in which the ratio of the volume average particle size and the number average particle size is less than three. This wet developer development characteristic has a charge-mass ratio (Q / M) of 200 µC / g or more, a mass-to-area ratio (M / A) of 200 µg / cm 2 or more.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments, but the present invention is not limited thereto.

Example 1

Isopar M as a carrier and methyl isobutyl ketone as a cosolvent were mixed at a mass ratio of 6: 4. 2.5 g of acid-treated ethylene vinyl acetate (Elvax, manufactured by Dupont) was mixed and Hansa brillant (PY74, manufactured by Clariant), permanent rubin F6B (PR184, manufactured by Clariant), PB15: 4 (Manufactured by Sun chemican) and monarch 120 (carbon black, manufactured by Cabot) were used as pigments. Next, 0.25 g of Disperbyk 116 (BYK) was mixed as a dispersant, 0.5 mm glass beads were put together in the vessel, and dissolved and dispersed using Dispermat (VMA GETZMANN) for 1.5 hours at 40 to 60 ° C. Subsequently, the mixture was stirred and cooled at room temperature for 2 hours to obtain toner particles having a volume average size of about 4 μm. Next, the toner particle dispersion solution obtained above was removed with methyl isobutyl ketone through a filtering process so that only pure Isopar M remained, and then a basic barium petronate (manufactured by Witco) and a dispersant were further added as a charge control agent. A malleable wet developer was obtained.

Example 2

A wet developer was prepared in the same manner as in Example 1 except that the mass ratio of the paraffinic hydrocarbon solvent and the cosolvent was 8: 2.

Example 3

A wet developer was prepared in the same manner as in Example 1 except that 4-methyl-2-pentanone was used as the cosolvent.

Example 4

A wet developer was prepared in the same manner as in Example 1 except that 2-methyl-3-hexanone was used as the cosolvent.

Example 5

A wet developer was prepared in the same manner as in Example 1 except that 5-methyl-2-hexanone was used as the cosolvent.

Example 6

A wet developer was prepared in the same manner as in Example 1 except that 5-methyl-3-hexen-2-one was used as the cosolvent.

Experimental Example

The properties of the wet developer prepared in Example 1-6 were measured and shown in Table 1 below.

Wet developer Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Remarks Post-Mass Mass / Area 241 218 236 231 230 229 Optimum range: 200 to 250 Conductivity (pMho / cm) 15.1 24 19 19 22 21 Optimum range: 10-30

As can be seen from the above results, it can be seen that the properties of the wet developer produced by the present invention are excellent.

As described above, the wet developer according to the present invention is environmentally friendly because it does not use an aromatic co-solvent, and is manufactured for a short time at a low temperature of 40 to 60 ° C., thus simplifying the manufacturing process and changing characteristics according to the type of pigment. Low particle distribution. In addition, there is an advantage that the secondary charging OPC can be used easier than the positive charging OPC by using the secondary charging toner.

Claims (7)

Paraffinic hydrocarbon solvent as a carrier and ketone organic solvent having a boiling point of 110 ° C or higher as a mixed solvent are used as a mixed solvent, and the glass transition temperature is 40 ° C to 70 ° C as a binder resin, and an acid-treated ethylene vinyl acetate resin, a pigment and a dispersant Wet developer, characterized in that it comprises a charge control agent. The method of claim 1, wherein the paraffinic hydrocarbon solvent is any selected from the group consisting of Isopar G, Isopar H, Isopar K, Isopar L, Isopar M, Isopar V, Norpar 12, Norpar 13, Norpar 15, Isodecane and IP solvent 1620 Wet developer, characterized in that one. The method of claim 1, wherein the ketone organic solvent is methyl isobutyl ketone, 4-methyl-2-pentanone, 2-methyl-3-hexanone, 5-methyl-2-hexanone and 5-methyl-3- Wet developer, characterized in that any one selected from the group consisting of hexen-2-one. The wet developer according to claim 1, wherein the mixed solvent has a mass ratio of 6: 4 to 8: 2. The wet developer of claim 1 wherein the pigment is selected from the group consisting of sunfast magenta, sunfast blue, benzidine yellow, quinacridone, carbon black and perylene green. The wet developer according to claim 1, wherein the dispersant is an acrylate copolymer or an amine compound. The wet developer according to claim 1, wherein the charge control agent is any one or a combination thereof selected from the group consisting of lecithin, basic barium petronate, and calcium petronate.