Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2002-03-19
2004-08-31
Sanders, Kriellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C106S447000, C106S448000, C106S493000, C106S494000, C106S498000, C548S305700
Reexamination Certificate
active
06784231
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to acetoacetic acid arylide type disazo pigments and to pigment dispersions thereof. More specifically, the present invention relates to an acetoacetic acid arylide disazo type pigment and to a pigment dispersion, which is useful in various applications, including coloring materials such as ink, paint, plastic, color toner, and color filter.
2. Description of Related Art
C.I. Pigment Yellow 180 including 2,2′-[1,2-ethanediyl-bis(oxy 2,1-phenyleneazo)] bis [N-(2,3-dihydro-2-oxo-1H-benzimidazole-5-yl)-3-oxo-butaneamide (hereinafter referred to as a basic substance) is known as a useful yellow colorant, and has been used for various purposes. The basic substance can be obtained by a diazocoupling reaction, and since it has the structure derived from one of the raw materials, i.e., a benzimidazolone compound, the pigment has significantly high light fastness, improved overcoating fastness when applied to paint, and improved migration fastness and high thermostability as applied to a synthetic resin. The term “pigment”, in contrast with the definition of a dye, means, in its broader application, fine powder which does not dissolve or is insoluble in water or organic solvent. This also applies to the above basic substance. In the present invention, in accordance with the above definition, a crude pigment, which will be described later, is also included in pigments.
Also, since 1,2-bis(2-aminophenoxy)-ethane, not dichlorobenzidines which are mutagenic, is used as the raw material for a bisdiazonium salt, which is the other substance used for the diazocoupling reaction, in the production of the basic substance, C.I. Pigment Yellow 180 is one of the few yellow colorant among acetoacetic acid arylid disazo type agents that can be used for, for instance, a preparation for electrostatic image developing toner, to which “Blauer Engel” (long title: “Das Umweltzeichen” meaning “environmental protection label”, a German ecological mark) certified by the German Confederation Environment Agency and operated by German Quality Assurance Label Association, is issued.
Japanese Unexamined Patent Application, First Publication No. Sho 56-38354, Japanese Unexamined Patent Application, First Publication No. Hei 8-209017, and Japanese Unexamined Patent Application, First Publication No. Hei 8-295815 disclose C.I. Pigment Yellow 180 containing the above basic substance.
Despite the above-mentioned broad definition of pigment, all of the conventional manufacturing methods for C.I. Pigment Yellow 180 described in these publications include a first process in which a bisdiazonium salt of 1,2-bis(2-aminophenoxy) ethane is coupled with 5-acetoacetylamino-benzimidazolone to obtain crude pigment, and a subsequent second process in which the crude pigment obtained in the first process is filtered and added to a liquid medium containing organic solvent as an essential component. Then, the liquid medium is subjected to a heat process and a colorant is produced.
Note that in this field of industry, the above-mentioned “crude pigment” has the same meaning as “prepigment” and “crude”. Likewise, the above-mentioned second process is also referred to as an aftertreating process, a finishing process, a conditioning process, or a pigmentization process. All of these terms have the same meaning.
On the other hand, the BET specific surface area based on the nitrogen absorption method, and the strength of each diffraction peak of a crystal based on Bragg angles measured by using CuK&agr; characteristic X-ray are examples showing important physical characteristics of pigment. These characteristics, together with the particle size of the pigment, are often used as indices for estimating characteristics of the pigment, such as the readiness of being dispersed in a dispersion medium, for example, vehicle, and the flow properties of a colored dispersion medium obtained.
In C.I. pigment Yellow 180 including the above mentioned basic substance, the particle size of the pigment affects various properties of a dispersion medium colored by using the colorant, such as brightness, transparency, color strength, hue, and flow properties, in the application of printing ink, for example. As for the pigment which has been subjected to the above second process, the smaller the particle size of primary particle thereof, the more its brightness, transparency, and color strength tend to increase. The reason for this is because, in the pigment whose degree of aggregation among particles is smaller (or weaker) than that of a crude pigment, which will be described later, the dispersibility of the primary particle thereof in a dispersion medium to be colored is better. In such a pigment, aggregation of the particles hardly occurs and they can be dispersed in a dispersion medium to be colored in a primary particle level. The measured specific surface area of such pigment having excellent brightness is larger than that of a crude pigment. That is, as for pigment which is subjected to the above second process, there is a tendency that the smaller the particle size of the primary particle of pigment, the larger the specific surface area thereof.
On the other hand, conventional crude pigments including the above basic substance corresponding to C.I. pigment Yellow 180 have lower crystallinity in the primary particle level and smaller particle size than the pigment which is subjected to the second process. Since the primary particles thereof are smaller as compared with the pigment subjected to the second process, the surface energy of the crude pigment is significantly higher, and as a result, the aggregation among the primary particles tends to increase in the crude pigment. Such a strong aggregation of the crude pigment cannot be decreased by using mechanical shearing strength. The specific surface area of such a crude pigment measured in the same manner as the pigment subjected to the second process, is smaller than that of a corresponding pigment. Moreover, if the crude pigment is directly used as a colorant, since the dispersibility thereof in a dispersion medium is insufficient, it is not useful in practice due to such factors as dullness. These are the conventional prevailing views as to the relationships between the physical characteristics of the crude pigment including the above basic substance and its practical applications.
Note that although it is possible to classify the above basic substance into crude pigment, which is not subjected to the second process, and pigment, which is subjected to both the first and the second processes, in the classification based on the manufacturing process as mentioned above, the basic substance is a pigment although it is subjected only to the first process, in the classification based on whether to satisfy various characteristics required for a colorant, regardless of the classification based on the manufacturing process, if it satisfies such characteristics required for a colorant. However, such a basic substance has not been obtained before the present invention.
As in the above conventional prevailing view, the basic substance obtained by the conventional methods described in the above publications is in a strong aggregated state, and the specific surface area thereof is 10 m
2
/g or less.
A powder X-ray diffraction diagram is a graph in which the strength of X-ray diffraction of a sample at each Bragg angle, when the Bragg angle is continuously changed, is consecutively plotted based on zero of the diffraction strength. The absolute strength of the X-ray diffraction at each Bragg angle can be determined based on zero of the diffraction strength in the powder X-ray diffraction diagram.
The inventors of the present invention paid attention to this point, and newly adopted, as a standard for clearly distinguishing a crude pigment, which is not subjected to the above second process in the classification based on the manufacturing process, from pigment, which is subjected to the above second process, th
Shimada Katsunori
Sunouchi Junko
Armstrong Kratz Quintos Hanson & Brooks, LLP
Dainippon Ink and Chemicals Inc.
Sanders Kriellion A.
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