Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or... – Identified color-former
Reexamination Certificate
2001-05-04
2003-07-01
Hess, B. Hamilton (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
Identified color-former
C503S215000, C585S025000, C585S469000
Reexamination Certificate
active
06586362
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a hydrocarbon solvent. More particularly, it relates to a hydrocarbon solvent comprising a fraction, which contains 1-phenyl-1-(p-isopropylphenyl)ethane that is obtained by reacting cumene and styrene, and a pressure-sensitive copying material, which is made with the above solvent.
BACKGROUND ART
It has hitherto been well known that the pressure-sensitive copying materials are prepared using various hydrocarbon solvents. For example, a sheet of paper (upper sheet) is applied with microcapsules enclosing a solution of an electron-donating color former (hereinafter referred to as “color former”), and another sheet of paper (substrate sheet) is applied with an electron-accepting substance (hereinafter referred to as “color developer”) such as clay and polymeric materials which can produce colors upon reacting with the above color former. When copying materials are used, the treated surfaces of the above-mentioned set of sheets are put together face to face and pressure is applied to the paired sheets by handwriting or typewriting, thereby obtaining duplicate recordings.
The recording mechanism of this type is such that the microcapsules are ruptured by the pressure of handwriting or the impact of typewriting to release the color former solution. The solution comes into contact with the color developer on the opposite surface of the other sheet of paper to produce a color. In other types of known copying materials, both a lower layer of color developer and an upper layer of microcapsules are applied to a surface of a substrate sheet, or a mixture of microcapsules and a color developer is applied to a substrate sheet.
The color former solution that is used for the copying materials of this kind is a solution of an electron-donating color former in one or more kinds of hydrophobic solvents.
As this type of color former solvent, 1-phenyl-1-(isopropylphenyl)ethane is proposed in Japanese Laid-Open Patent Publication No. 48-92115. The above 1-phenyl-1-(isopropylphenyl)ethane is a satisfactory solvent because it is odorless and be excellent in color-developing property. In addition, it can be produced without difficulty by reacting cumene with styrene as disclosed in the above reference, and it is also favorable in industrial viewpoint because the cumene and styrene as starting materials are inexpensive.
As disclosed in the above publication, 1-phenyl-1-(isopropylphenyl)ethane may include three kinds of isomers, namely, o-, m- and p-isomers, according to the positions of isopropyl groups on the benzene ring. As the result of investigation by the present inventors, it was found out that p-isomer is most excellent in the solvent property for dyestuffs, in addition, it is low in viscosity. Therefore, it is high in color-developing rate, while the other isomers do not necessarily have these desirable properties.
The above-mentioned patent reference describes, with referring to British Patent No. 896864, that 1-phenyl-1-(isopropylphenyl)ethane can be produced easily by reacting cumene and styrene according to this method. However, the conventional catalyst containing acid-treated clay catalyst as proposed in the above British Patent is not always sufficient in the selectivity for producing p-isomer. Therefore, the 1-phenyl-1-(isopropylphenyl)ethane that is described in examples of the above patent is not always satisfactory in the solubility for dyestuffs, the color-developing rate and so forth, and besides, a large quantity of styrene dimers are produced as by-products.
It is also the case with the method described in Japanese Laid-Open Patent Publication No. 48-92114, in which sulfuric acid is used as a catalyst in the reaction of cumene and styrene, or with the method described in Japanese Laid-Open Patent Publication No. 49-31652, in which acid clay is used.
Furthermore, in the production of 1-phenyl-1-(isopropylphenyl)ethane by reacting styrene and cumene as described above, two kinds of styrene dimers are produced as by-products. In addition, these dimers differ from 1-phenyl-1-(isopropylphenyl)ethane in the number of carbon atoms by only one, therefore, the boiling points of them are close to each other. Accordingly, when distillation is employed for the separation in an industrial scale, the dimers are liable to be entrained into the fraction containing 1-phenyl-1-(isopropylphenyl)ethane.
The two kinds of styrene dimers produced as by-products are 1,3-diphenylbutene and 1-methyl-3-phenylindane. Between them, 1-methyl-3-phenylindane, particularly, sometimes produces undesirable effect on the odor of products.
The object of the present invention is to provide a hydrocarbon solvent which is inexpensive and has excellent properties, especially a hydrocarbon solvent consisting of 1-phenyl-1-(p-isopropylphenyl)ethane that is excellent in the dissolving power for dyes and color-developing rate, and is odorless without any problem. Another object of the invention is to provide a pressure-sensitive copying material that is made using the above solvent.
A first aspect of the present invention, therefore, relates to a hydrocarbon solvent characterized in that the solvent comprises a fraction which is produced by reacting styrene and cumene in the presence of an acid catalyst. The fraction contains 85% by weight or more of 1-phenyl-1-(p-isopropylphenyl)ethane and 5% by weight or less of total content of styrene dimers.
A second aspect of the present invention relates to a hydrocarbon solvent as described in the above first aspect, in which the weight ratio of 1,3-diphenylbutene to 1-methyl-3-phenylindane in the styrene dimers is 0.02 or less.
A third aspect of the present invention relates to a pressure-sensitive copying material, which comprises an electron-accepting color developer and a solution of electron-donating color former that is dissolved in a hydrocarbon solvent as described in the above first or second aspect, the color former producing a color when it is brought into contact with the above color developer.
A fourth aspect of the present invention relates to a pressure-sensitive copying material as described in the third aspect, which comprises microcapsules enclosing a solution of electron-donating color former and a sheet-like support carrying there on the microcapsules.
The present solvent contains a large quantity of the p-isomer of 1-phenyl-1-(isopropylphenyl)ethane, so that it is excellent in dissolving power for dyes and color-developing rate. Moreover, because the content of 1,3-diphenylbutene relative to the styrene dimers is small, disagreeable odor is not produced. Furthermore, because 1-phenyl-1-(isopropylphenyl)ethane according to the present invention can be produced without difficulty by reacting cumene with styrene, the obtained solvent is inexpensive.
DISCLOSURE OF INVENTION
In the following, the present invention will be described in more detail.
As the 1-phenyl-1-(isopropylphenyl)ethanes, there are three kinds of position isomers, in which isopropyl group occupies o-, m- and p-positions. That is, 1-phenyl-1-(o-isopropylphenyl)ethane, 1-phenyl-1-(m-isopropylphenyl)ethane, and 1-phenyl-1-(p-isopropylphenyl)ethane. Concerning the hydrocarbon solvent according to the present invention, it is most important that the content of the p-isomer of 1-phenyl-1-(p-isopropylphenyl)ethane in the whole solvent is 85% by weight or more. Both 1-phenyl-1-(o-isopropylphenyl)ethane and 1-phenyl-1-(m-isopropylphenyl)ethane are higher in viscosity than that of 1-phenyl-1-(p-isopropylphenyl)ethane, and their dissolving power for color formers used in pressure-sensitive copying material are smaller. Accordingly, if the content of 1-phenyl-1-(o-isopropylphenyl)ethane and 1-phenyl-1-(m-isopropylphenyl)ethane in the solvent exceeds 15% by weight, the properties as a pressure-sensitive copying material are unfavorably inferior to the hydrocarbon solvent of the present invention.
Furthermore, if the total amount of styrene dimers of 1,3-diphenylbutene and 1-methyl-3-phenylindane in the solvent is 5.0% by weight or more, the odor is too strong w
Shoko Toshikatsu
Togami Yasuo
Hess B. Hamilton
Hollander Law Firm, P.L.C.
Nippon Petrochemicals Company Limited
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