Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Screen other than for cathode-ray tube
Reexamination Certificate
2000-10-30
2004-02-24
McPherson, John A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
Screen other than for cathode-ray tube
C430S270100, C430S281100, C106S499000
Reexamination Certificate
active
06696207
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a pigment composition that can be employed as a coating material for automobiles, painted steel sheets, building materials, cans and the like; as a printing ink such as lithographic printing ink, rotogravure ink, flexographic ink, or ink-jet printing ink; or as the material for a color filter. The present invention further relates to a pigment dispersion liquid in which this pigment composition is dispersed.
RELATED ART
Various properties are required of pigments. For example, they must be readily dispersed in the dispersion resin or solvent system (i.e., they must have good dispersibility), the liquid containing the dispersed pigment must have excellent flow qualities, and the paint film formed by coating the liquid with the dispersed pigment must have high gloss, brightness, and resistance to weather. Moreover, in the case of color filters in particular, the paint film must have high contrast and high transparency. In order to satisfy these requirements, a variety of treatments are carried out to a crude pigment obtained by synthesis. The material rendered as a result of these treatments can then be employed as a pigment.
Specifically, after carrying out such processes as adjusting the crystal form, and adjusting the shape and size of the primary particles in the process for rendering a pigment from the crude pigment material, various treatments are performed using pigment derivatives, rosins, modified rosins, body extender pigments, resins for micro-encapsulation, and the like, with the objective of stabilizing the particle diameter, inhibiting crystal growth and aggregation, providing good dispersibility to the various resin and solvent systems used to disperse the pigment, providing suitable flow qualities to the pigment dispersion liquid, improving the gloss of the paint film, and improving the brightness of the paint film.
However, few pigments possess the numerous properties described above. This is because a pigment having these numerous properties would be very expensive, so that its practical use would not be feasible. Namely, many treatments would have to be carried out in order to provide a pigment with these numerous properties, thus the cost for treatment agents would increase. Moreover, there would be more operational steps as the number of treatments grew, so that the price of the pigment would rise. Accordingly, rather than using an expensive pigment with superior properties, it is actually the usual practice to select an inexpensive resin from among the various products that is suitable to the resin or solvent system to be used. However, these inexpensive pigments frequently sacrifice any number of the properties that are required of a pigment.
The conventional technology relating to pigment compositions will now be discussed as follows.
Untreated pigments in which the crystal form of the crude pigment and the shape and size of the primary particles have been adjusted in the pigment rendering process, but no surface treatment employing the aforementioned treatment agents has been performed, are inexpensive. However, the range within which they can be employed is limited. Moreover, in a disperse system, these pigments are prone to such problems as crystal growth and aggregation, and poor dispersion liquid flow properties.
On the other hand, rosins and modifiable rosins which have shown promise in lithographic, typographic and other such printing ink applications ink are frequently employed in treatments when forming the pigment, in order to maintain a uniform crystal system and particle diameter in the pigment. However, these treatment agents impair the flow properties of the pigment dispersion liquid, and it has thus been indicated that their use in applications that require good flow properties is problematic.
In pigment compositions consisting of an organic pigment and a body extender pigment, there are cases in which the body extender pigment functions only as an extending agent. In many cases however, the body extender pigment may also serve such functions as improving the dispersibility of the pigment and the flow properties of the pigment dispersion liquid, or have such characteristics as providing a high gloss, high brightness paint film. In addition, many pigment compositions employ body extender pigments because they are inexpensive. However, problems with body extender pigments have also been cited, such as the brittleness of the paint film when these pigments are employed in industrial coating materials where hardness is required of the paint film, or low contrast when these pigments are employed in color filters of liquid crystal displays.
Pigment compositions in which pigment derivatives and dyes have been added in addition to the pigments are effective in improving pigment dispersibility, controlling crystal growth and aggregation, and improving the flow properties of the pigment dispersion liquid. In addition, these compositions are not readily affected by various solvents. Further, the paint film often demonstrates an improvement in gloss, brightness, transparency, and contrast. In addition, another characteristic of these pigment compositions is their low cost. Specific examples of such pigment compositions include the pigment C.I. Pigment Red 177 containing 4,4′-diamino-1,1′-dianthraquinonyl-3,3′-disulfonic acid that is disclosed in Japanese Patent Application, First Publication No. Sho 63-172772; copper phthalocyanine pigment containing copper phthalocyanine sulfonic acid pigment derivative disclosed in Japanese Patent Application, First Publication No. Hei 4-146968; and halogenated copper phthalocyanine pigment containing halogenated copper phthalocyanine sulfonic acid pigment derivative disclosed in Japanese Patent Application, Second Publication No. Sho 41-2466. However, as the amount of pigment derivative and dye increase, the paint film's resistance to light, weather, heat and the like fall, and the pigment derivative and dye often bleed to the surface of the paint film.
Much research has been carried out in recent years, with microencapsulated pigments being highly appraised with respect to the flow properties, stability and pigment dispersibility of the dispersion liquid in which the pigment composition is dispersed. However, due to the high costs associated with the pigment treatment, the use of these microencapsulated pigments is problematic in industrial fields where a low cost material is required.
A metal salt pigment composition of chromic acid subjected to an ester treatment as disclosed in Japanese Patent Application, First Publication No. Sho 62-184063 may be cited as an example of a conventional technique employing a carboxylic acid ester compound that is related to the present invention. This composition intends an improvement in heat stability, chemical stability, and color fastness to light.
The conventional technology for improving the nature of the liquid and paint film of the pigment dispersion liquid will now be explained.
The pigment dispersion liquid is formed of a pigment composition, resin, dispersion enhancer, solvent and the like. A material having the function of improving the nature of the pigment dispersion liquid can be included in one or more of the compositional starting materials. Typically, in a coating material, numerous colors are produced by holding the resin and solvent constant, and changing the pigment. For this reason, the function of improving the nature of the pigment dispersion liquid is generally provided to the pigment composition or the dispersion enhancer. In particular, as a known technique related to the present invention, an example may be cited in which pigment dispersibility and the like are improved by employing ester carboxylic acid compounds as the vehicle or dispersing agent, such as disclosed in Japanese Patent Applications, First Publication Nos. Sho 47-6771, Sho 60-215651, Sho 63-214330, Hei 2-129147, and Hei 3-227371, Published Japanese Translation No. Hei 4-506225 of a PCT international publication, Jap
Araki Shingo
Iwasaki Kenji
Kawase Ichiro
Murata Haruo
Dainippon Ink and Chemicals Inc.
McPherson John A.
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