Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-03-15
2001-10-30
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C528S488000, C528S489000, C427S222000, C428S403000
Reexamination Certificate
active
06310117
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for coating wax or resin particles with metallic soap. The present invention further relates to metallic-soap-coated wax or resin particles having anti-blocking properties obtained by the method.
2. Description of the Prior Art
Wax or resin particles are utilized widely as a lubricant, a modifier, an additive or the like. In particular, in the field of toners for electrophotography, wax or resin particles serve as important elements: for example, wax particles are used as an external additive or an internal additive, and resin particles are used as a carrier of toner or a fixing agent.
In this context, in recent years there has been an increasing demand for the improvement of the resolution of an image formed of toner and full colorization of toner, and the dot size has been miniaturized. Under these circumstances, the particle size of wax or resin particles used as an additive or toner carrier is also required to be miniaturized to 50 &mgr;m or less or even 25 &mgr;m or less.
However, since fine particles of wax or resin are likely to cause blocking, some problems, such as failure to form a complete image due to the blocking of the particles, have started to arise with the development of the miniaturization of the particle size.
In order to prevent this blocking, an attempt to coat the surfaces of wax or resin particles with metallic soap has been made. For example, the surfaces of the wax or resin particles are coated using the following methods: a method of coating the particle surfaces with powder metallic soap in a mixing granulating machine such as a High Speed mixer (Mitsui Mining Co., Ltd.) and a Marumerizer (Fuji Paudal Co., Ltd.); and a wet coating method which adds metallic soap in the form of water dispersion to the particles and dries the resultant product so as to coat the surfaces of the particles with the metallic soap (e.g., Japanese Laid-Open Patent Publication Nos. 58-100857, 8-182927, and 9-328559). Furthermore, various methods for coating the particle surfaces with metallic soap have been proposed to prevent the blocking of the particles used in photography or other applications. Examples of proposed methods include a method of coating the particle surfaces with metallic soap with a V-blender so as to produce a developer for an electronic copying machine (Japanese Laid-Open Patent Publication No. 59-229567); a method of coating the surface of a pigment with silicone oil, resin, metallic soap or the like to make the surface of the pigment lipophilic so as to produce color microcapsules (Japanese Laid-Open Patent Publication No. 62-234541); and a method of fixing fatty acid metallic soap to the surface of toner by the method of the mechanical mixing so as to produce microcapsule toner (Japanese Laid-Open Patent Publication No. 6-242627).
In order to coat the particles with metallic soap uniformly by these conventional methods, in general, the desirable particle size of the metallic soap added is at least one-fifth or smaller, preferably one-twentieth or smaller than that of the particles to be coated with the metallic soap. However, the particle size of industrially available metallic soap at present is 5 to 50 &mgr;m. Therefore, it is not easy to coat wax or resin particles having a particle size of 100 &mgr;m or smaller by the conventional methods, and it is very difficult to uniformly coat particles having a particle size of 25 &mgr;m or smaller by the conventional methods.
For this reason, although metallic soap has excellent lubricating properties, release properties, and anti-moisture absorption as an anti-blocking agent, the metallic soap cannot be used for coating the surface of wax or resin particles having a particle size of 50 &mgr;m or smaller or even 25 &mgr;m or smaller. Therefore, the metallic soap cannot be used in the field of toner for high definition electrophotography.
SUMMARY OF THE INVENTION
As a result of great efforts made to solve the abovedescribed problems, the inventors of the present invention found that microparticles covered with a layered or scaly coating of metallic soap can be obtained by mixing a water dispersion of wax or resin particles dispersed in water, using water-soluble fatty acid soap as a dispersant, and an aqueous solution or a dispersion of a polyvalent metal compound.
More specifically, the present invention is directed to a method for coating wax or resin particles with metallic soap, wherein (a) a water dispersion of wax or resin particles, the dispersion containing water-soluble fatty acid soap, and (b) an aqueous solution or a water dispersion of a polyvalent metal compound are mixed in such a manner that the equivalent ratio of the polyvalent metal compound to the water-soluble fatty acid soap is 0.5 to 1.5.
In a preferred embodiment, the above-mentioned wax or resin particles are contained in an amount of 0.1 to 50 wt % in the water dispersion (a) of wax or resin particles, and the water-soluble fatty acid soap is contained in an amount of 0.1 to 20 parts by weight per 100 parts by weight of the wax or resin particles.
In a preferred embodiment, the polyvalent metal compound is contained in an amount of 0.01 to 30 wt % in the aqueous solution or the water dispersion (b).
The present invention further relates to wax or resin particles coated with metallic soap obtained by the steps of: (i) mixing (a) a water dispersion of wax or resin particles, the dispersion containing water-soluble fatty acid soap, and (b) an aqueous solution or a water dispersion of a polyvalent metal compound in such a manner that an equivalent ratio of the polyvalent metal compound to the water-soluble fatty acid soap is 0.5 to 1.5; and (ii) recovering the resultant wax or resin particles coated with metallic soap.
Thus, the invention described herein makes possible the advantages of: (1) providing a method for coating fine particles of wax or resin with metallic soap uniformly in order to obtain coated particles which can be used in various industrial fields such as electronics, information, medicine and pharmacy, cosmetics, and resin processing, in particular, in the field of toner for high definition electrophotography; and (2) providing metallic-soap-coated wax or resin particles having anti-blocking properties obtained by the method.
These and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.
REFERENCES:
patent: 5248581 (1993-09-01), Nakayama et al.
patent: 5621023 (1997-04-01), Nishimura et al.
patent: 6060553 (2000-05-01), Lenczyk et al.
patent: 58100857 (1981-12-01), None
patent: 57063336A (1982-04-01), None
patent: 59229567 (1983-02-01), None
patent: 62234541 (1986-04-01), None
patent: 03243639A (1991-10-01), None
patent: 04220441A (1992-08-01), None
patent: 6242627 (1993-02-01), None
patent: 8182927 (1994-12-01), None
patent: 9328559 (1997-02-01), None
Onodera Show
Sawada Kouhei
Amin & Turocy LLP
NOF Corporation
Yoon Tae H.
LandOfFree
Method for coating wax or resin particles with metallic soap does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for coating wax or resin particles with metallic soap, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for coating wax or resin particles with metallic soap will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2598596