Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or... – Spatial relationship specified between color-former and...
Reexamination Certificate
2001-12-04
2004-10-05
Hess, B. Hamilton (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
Spatial relationship specified between color-former and...
C503S200000
Reexamination Certificate
active
06800588
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermal recording material, in particular to one having the advantages of high sensitivity, high-density color image formation thereon, good resistance to plasticizers, good resistance to ink for inkjet systems, good traveling in processing and printing systems, good handlability (resistance to rubbing), and good printability.
2. Description of the Related Art
Reaction of a basic leuco-dye with an organic acid substance when melted under heat to form colors has been known in the art. The color-forming reaction applies to various types of recording paper (thermal recording materials).
As being relatively inexpensive and capable of being processed in compact recording appliances not requiring specific maintenance, thermal recording materials are widely used in the art. For example, they are used in the field of instrumental recorders, terminal printers for computers, facsimiles, vending machines, bar-code labelers, etc. The recent requirement for such thermal recording materials is that they shall have high-level quality. Specifically, the indispensable properties of thermal recording materials for such applications are that their whiteness is high and their sensitivity (color-forming ability) is high and good, and that high-density images can be formed thereon.
After printed thereon, thermal recording materials are often stored and/or transported while kept in contact with polyvinyl chloride or the like. Therefore, they are required to be resistant to plasticizers such as polyvinyl chloride.
The resistance of thermal recording materials to plasticizers such as polyvinyl chloride can be improved in some degree by suitably selecting the constitutive components such as electron-donating leuco-dyes and electron-receiving compounds for them, or by forming a protective layer on the materials. For example, it is known that using 2,2-bis(4-hydroxyphenyl)propane (bisphenol A, BPA) for the electron-receiving compound in the materials improves the plasticizer resistance of the materials, but is not satisfactory. On the other hand, it is also known that a protective layer of polyvinyl alcohol or the like, if formed thereon, improves the plasticizer resistance of the materials.
However, in cases where thermal recording materials are used for tickets and the like, they require a combined system of thermal recording and offset printing for printing image information thereon. In that case, the protective layer, if on the thermal recording materials for such applications, often causes uneven ink adhesion to the materials printed in offset systems, and, as a result, the materials lose good printability. (The “printability” is in offset printing systems, and the same shall apply hereinafter.)
On the other hand, recently, inkjet printers have become popular for directly outputting data in prints from personal computers. In offices and others in that situation, inkjet recording materials and thermal recording materials are often put together while their recording faces are kept in contact with each other. However, conventional thermal recording materials are not satisfactorily resistant to ink for inkjet printers. Therefore, when the recording face of such thermal recording materials is kept in contact with that of inkjet recording materials, there often occurs a problem in that the density of the images formed on the materials is lowered. To solve the problem, thermal recording materials are further required to have good resistance to inkjet ink.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the problems noted above, and an object of the present invention is to provide a thermal recording material having the advantages of high sensitivity, high-density color image formation thereon, good resistance to plasticizers, good resistance to ink for inkjet systems, good traveling in processing and printing systems, good handlability (resistance to rubbing), and good printability.
The above object of the present invention is attained as follows.
In its first aspect, the present invention provides a thermal recording material including a support, and a thermal color forming layer and a protective layer formed in that order on the support, the thermal color forming layer containing an electron-donating leuco-dye and an electron-receiving compound, and the protective layer containing inorganic pigment and at least one of amide-denatured polyvinyl alcohol and diacetone-denatured polyvinyl alcohol.
Subsidiary to the first aspect thereof, the second aspect of the present invention indicates that the protective layer in the thermal recording material includes an overcoat layer (A), which contains as principal constituents inorganic pigment and a water-soluble polymer, and another overcoat layer (B), which is formed on the overcoat layer (A) and contains as principal constituents a lubricant and another water-soluble polymer, and that the water-soluble polymer contained in the overcoat layer (A) includes at least a portion of the at least one of amide-denatured polyvinyl alcohol and diacetone-denatured polyvinyl alcohol.
In a preferred embodiment of the first aspect, the protective layer further contains a surfactant; in another preferred embodiment thereof, the protective layer contains at least one water-soluble polymer selected from the group consisting of denatured polyvinyl alcohols, starch, oxidized starch, urea-phosphorylated starch, styrene-maleic anhydride copolymers, alkyl esters of styrene-maleic anhydride copolymers, and styrene-acrylic acid copolymers; and in still another preferred embodiment thereof, the protective layer has a thickness of from 0.5 &mgr;m to 3 &mgr;m.
Subsidiary to the first aspect thereof, a third aspect of the present invention indicates that the at least one of amide-denatured polyvinyl alcohol and diacetone-denatured polyvinyl alcohol in the thermal recording material is crosslinked by a crosslinking agent.
In a preferred embodiment of this aspect, the amount of the crosslinking agent to be added is in the range of 2 to 40% by weight of at least one of the amide-denatured polyvinyl alcohol and diacetone-denatured polyvinyl alcohol; in another preferred embodiment this aspect, the crosslinking agent is selected from the group consisting of polyaldehyde compounds, titanium lactate, dihydrazide compounds and boric acid; in still another preferred embodiment thereof, the crosslinking agent is selected from polyaldehyde compounds and titanium lactate.
Also preferably in the second aspect, the crosslinking agent is in the overcoat layer (A).
Subsidiary to the first aspect thereof, a fourth aspect of the present invention indicates that the inorganic pigment in the thermal recording material comprises at least one selected from the group consisting of kaolin, aluminum hydroxide, calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, barium sulfate, zinc sulfate, talc, clay, calcined clay and colloidal silica.
Preferably in this, the amount of the inorganic pigment in the protective layer is in the range of 10 to 90% by weight of the layer.
Subsidiary to the second aspect thereof, the fourth aspect of the present invention indicates that the lubricant in the thermal recording material is at least one selected from the group consisting of zinc stearate, calcium stearate, paraffin wax, microcrystalline wax, carnauba wax, and synthetic polymer wax. Preferably in this, the lubricant has a mean particle size of at most 0.5 &mgr;m.
Subsidiary to the first aspect thereof, a fifth aspect of the present invention indicates that the electron-receiving compound in the thermal recording material is at least one selected from the group consisting of 2,4′-dihydroxydiphenyl sulfone, 2,4-bis(phenylsulfonyl)phenol, 4,4′-sulfonylbis(2-(2-propenyl)phenol) and 2-hydroxy-4′-isopropoxydiphenyl sulfone.
Subsidiary to the first aspect thereof, a sixth aspect of the present invention indicates that the electron-donating leuco-dye in the thermal
Iwasaki Masayuki
Matsumoto Takayuki
Mitsuo Hirofumi
Takeuchi Tetsuo
Fuji Photo Film Co. , Ltd.
Hess B. Hamilton
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