Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or... – Method of use – kit – or combined with marking instrument or...
Reexamination Certificate
2001-09-12
2004-04-13
Hess, B. Hamilton (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
Method of use, kit, or combined with marking instrument or...
C503S208000, C503S209000, C503S216000
Reexamination Certificate
active
06720286
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heat-sensitive recording material, particularly to a heat-sensitive recording material having high coloring density, little fogging at non-image portions and excellent image preservability.
2. Description of the Related Art
Generally, heat-sensitive recording materials have been widely used for the reason that the heat-sensitive recording materials are relatively inexpensive, and because recording equipment therefor is compact and maintenance-free. Under such circumstances, recently, sales of heat-sensitive paper have become competitive, there has been a demand for heat-sensitive recording materials having functions greater than those of the past. Moreover, coloring density, image preservability, and the like of heat-sensitive recording materials are being extensively researched.
As electron-accepting compounds for colorless electron-donating dyes used for such heat-sensitive recording materials, conventionally, 2,2-bis (4-hydroxyphenyl) propane (so-called “bisphenol A”) has been widely used. However, a compound satisfying demands made with respect to sensitivity, fogging and image preservability has not been obtained yet.
Further, there has been an escalation in recent years in the use of ink jet printers. Accompanying this escalation has been a trend to overlap ink jet recording sheet and heat-sensitive recording material after an image has been recorded thereon.
However, when an ink jet recording sheet and a heat-sensitive recording material, with images recorded thereon, are placed so as to overlap each other, respective recording surfaces thereof contact each other. In conventional heat-sensitive recording materials, there is the problem that density of image portions becomes low and fogging of non-image portions grows worse. As a result, there have been cases in which the purpose of the heat-sensitive recording material as a recording material is compromised.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a heat-sensitive recording material having high coloring density, little fogging at non-image portions, and excellent preservability of image portions.
As a result of their investigations into electron-accepting compounds, sensitizers, and the like, the present inventors strove to develop a recording material having excellent functional properties and completed the present invention. Namely, a first aspect of the present invention is a heat-sensitive recording material comprising: a substrate; and a heat-sensitive coloring layer formed on the substrate, the heat-sensitive coloring layer including (a) a colorless electron-donating dye, (b) an electron-accepting compound including at least 4,4′-dihydroxydiphenylsulfone, and (c) a sensitizer comprising 2-benzyloxynaphthalene and aliphatic monoamide.
A second aspect of the present invention is a method of forming a heat-sensitive recording material, comprising the steps of: (a) dispersing a colorless electron-donating dye, an electron-accepting compound, comprising at least 4,4′-dihydroxydiphenylsulfone, and a sensitizer comprising 2-benzyloxynaphthalene and aliphatic monoamide in a water-soluble binder to form a coating material; (b) drying a film of the coating material on a substrate to form a heat-sensitive coloring layer; and (c) smoothing the heat-sensitive coloring layer.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A heat-sensitive recording material of the present invention comprises a substrate, and a heat-sensitive coloring layer disposed on the substrate and containing a colorless electron-donating dye and an electron-accepting compound. The above-described heat-sensitive coloring layer contains, as the electron-accepting compound, at least 4,4′-dihydroxydiphenylsulfone, and also contains a sensitizer comprised of 2-benzyloxynaphthalene and aliphatic monoamide in a mass ratio (2-benzyloxynaphthalene/aliphatic monoamide) ranging from 30/70 to 70/30. The heat-sensitive recording material of the present invention will be hereinafter described.
1. Substrate
Conventionally known substrates can be used as the substrate in the present invention. Specifically, paper substrates of fine-quality paper, coat paper with resin or pigment applied thereto, resin-laminated paper, fine-quality paper having an undercoat layer, synthetic paper, plastic film, and the like can be used.
A smooth substrate in which smoothness prescribed by JIS-8119 is in a range of 300 to 500 seconds is preferable as the substrate from the standpoint of dot reproducibility.
The substrate used in the present invention may also include an undercoat layer. When an undercoat layer is provided on the substrate, an undercoat layer containing a pigment as a main component is preferably used. Conventional organic and inorganic pigments can be used. Particularly, a pigment in which oil absorbency prescribed by JIS-K5101 is 40 ml/100 g (cc/100 g) or more is preferably used. Specific examples of the pigment include calcium carbonate, barium sulphate, aluminum hydroxide, kaolin, calcined kaolin, amorphous silica, urea-formaline resin powder, and the like. Among these pigments, calcined kaolin having an oil absorbency of 70 to 80 ml/100 g is particularly preferable.
Further, an amount of the pigment to be applied to the substrate is 2 g/m
2
or greater, preferably 4 g/m
2
or greater, and most preferably 7 to 12 g/m
2
.
Examples of binders used for the above-described undercoat layer include water-soluble polymers and water-soluble binders. These binders may be used singly or may be used in a combination of two or more. Examples of the water-soluble polymer include starch, polyvinyl alcohol, polyacrylamide, carboxymethyl alcohol, methylcellulose, or casein.
The water-soluble binder is generally a synthetic rubber latex or a synthetic resin emulsion. Examples of the water-soluble binder include styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, methyl acrylate-butadiene rubber latex, vinyl acetate emulsion, and the like.
An amount of the binder used is 3 to 100% by weight, preferably 5 to 50% by weight, and most preferably 8 to 15% by weight of the total weight of the pigment added to the undercoat layer. Further, waxes, discoloration inhibitors, surfactants, and the like may be added to the undercoat layer.
Generally known coating methods can be used to apply the undercoat layer. Specifically, coating methods using air knife coaters, roll coaters, blade coaters, gravure coaters, curtain coaters, and the like can be used. Among these methods, a coating method using blade coaters is preferably used. Further, if necessary, smoothing such as calendering may also be carried out.
2. Heat-sensitive Coloring Layer
A heat-sensitive coloring layer formed on the substrate contains at least (1) a colorless electron-donating dye, (2) an electron-accepting compound, and (3) a sensitizer, and more preferably, also contains (4) an image stabilizer. Further, the heat-sensitive coloring layer is preferably formed directly on the substrate.
(1) Colorless Electron-donating Dye
Examples of the colorless electron-donating dye include compounds described below. However, the present invention is not limited to the same. Namely, examples of the colorless electron-donating dye that colors to black, include 3-di(n-butylamino)-6-methyl-7-anilinofluoran, 2-anilino-3-methyl-6-N-ethyl-N-sec-butylaminofluoran, 3-di(n-pentylamino)-6-methyl-7-anilinofluoran, 3-(N-isoamyl-N-ethylamino)-6-methyl-7-anilinofluoran, 3-(N-n-hexyl-N-ethylamino)-6-methyl-7-anilinofluoran, 3-[N-(3-ethoxypropyl)-N-ethylamino)-6-mehyl-7-anilinofluoran, 3-di(n-butylamino)-7-(2-chloroanilino)fluoran, 3-diethylamino-7-(2-chloroanilino)fluoran, 3-diethylamino-6-methyl-7-anilinofluoran, and 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluoran.
Among these compounds, 3-di(n-butylamino)-6-methyl-7-anilinofluoran and 2-anilino-3-methyl-6-N-ethyl-N-sec-butylaminofluoran are preferable from the standpoint of low fogging at non-image portions.
An amount of the colorle
Iwasaki Masayuki
Mitsuo Hirofumi
Fuji Photo Film Co. , Ltd.
Hess B. Hamilton
LandOfFree
Heat-sensitive recording material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Heat-sensitive recording material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Heat-sensitive recording material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3195690