Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or... – Having nonchromogenic liquid spread-control or...
Reexamination Certificate
1999-12-01
2002-08-13
Hess, Bruce H. (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
Having nonchromogenic liquid spread-control or...
C503S208000
Reexamination Certificate
active
06432875
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermal recording material with improved preservative stability after color development and recording. Particularly, the present invention relates to a thermal recording material in which chromogenic sensitivity is superior because a (poly) 4-hydroxybenzoic acid ester derivative, a particular condensation reaction product, is contained in a thermal recording layer and also in which the preservative stability such as heat resistance, light resistance, and oil resistance of the thermal recording material recorded by color developing (hereinafter, referred to as “a recording material body”) is improved.
2. Description of the Related Art
A thermal recording material is manufactured by applying a chromogenic substance which is usually colorless or hypochromic and a developer which develops chromogenic substance with heat to a surface of a supporting member such as paper, synthetic paper, a plastic film, or a sheet along with a sensitizer, a binder and other additives. When an exothermic device such as a thermal head and a thermal pen comes into contact with a recording apparatus, the chromogenic substance reacts with the developer to turn to be black and the like so as to obtain a thermal recording body. Since this thermal recording body is superior due to no necessity of a complex treatment such as development or fixation compared with another recording body using other means, obtainability of record by a relatively simple apparatus and in a sort time, a small noise during recording, low-level environmental pollution, and low cost, this recording body is not only utilized for copying books, documents, and the like but also is widely utilized as a recording material for a various recording papers for measurement, a computer, a facsimile, a telex, an automat for a ticket and the like, a prepaidcard, a label and the like.
From the viewpoint of initial color development sensitivity of the thermal recording body and dirt of a ground portion (ground portion fog), conventional thermal recording materials have actually satisfactory quality, when a chromogenic substance (a leuco dye), the developer which develops color with heat, and the sensitizer which is utilized as needed are used in a proper combination.
However, the thermal recording body using these conventional thermal recording materials has defects such as fading or disappearance of a printing portion when the thermal recording body is exposed to sunlight or lighting for a long time, and yellowing the ground portion. Therefore, when the recording bodies which are printed out by a facsimile, a word processor or a computer are allowed to stand on a desk, recorded images become smudgy to cause a problem in storage documents for a long time.
Moreover, as described above, the thermal recording body using the conventional thermal recording material is inferior in light resistance, and also when the thermal recording body is stored under high temperature and/or high humidity, there are defects such as disappearance of the printing portion or the generation of ground portion fog. Thus, there has been a long felt need for improvement in the preservative stability of a thermal recording body.
As disclosed in Japanese Unexamined Patent Publication Nos. Showa 56-144193, 58-188842, 60-64890, 63-252782 and the like, 4-hydroxybenzoic acid ester derivatives have been proposed to use as developers, and they are sill utilized now. However, although these compounds have satisfactory chromogenic sensitivity, preservative stability of the thermal recording body is not satisfactory, so that a further improvement has been desired.
In addition, as disclosed in Japanese Unexamined Patent Publication No. Heisei 2-122978 and the like, a thermal recording material using an aromatic carboxylic acid ester derivative of pentaerythritol is proposed, and as disclosed in Japanese Unexamined Patent Publication No. Heisei 2-172789 and the like, another thermal recording material using an aromatic carboxylic acid ester derivative of trimethylol alkane is proposed. However, although these compounds are superior in compatibility with various additives to be used for the thermal recording material, they only function as a snsitizer and do not have developing ability, so that they do seldom contribute to the above described improvement of the preservative stability.
SUMMARY OF THE INVENTION
It is an object of the present invention is to provide a thermal recording material having superior initial color development sensitivity as conventional materials and also having a superior preservative stability as a thermal recording body.
After conducting an intensive research and investigation to solve the above described disadvantage, the inventors have discovered that a thermal recording material having superior initial color development sensitivity and also having a superior preservative stability can be obtained by adding a (poly) 4-hydroxybenzoic acid ester derivative which is a certain condensation reaction product having a particular molecular structure into a thermal recording layer, and have attained this invention.
A summary of the present invention will be described below.
In a first aspect, the present invention provides a thermal recording material including a condensation reaction product (hereinafter, the condensation reaction product will be simply referred to as a (poly) 4-hydroxybenzoic acid ester derivative) of a carboxylic acid component (A) with a polyhydric alcohol component (B) in a thermal recording layer as an essential component, wherein the carboxylic acid component (A) includes a (poly) 4-hydroxybenzoic acid represented by the following general formula (I) as an essential component and another monocarboxylic acid and/or dicarboxylic acid as an arbitrary component, and wherein the polyhydric alcohol component (B) includes a polyhydric alcohol which is a trihydric or more alcohol as an essential component and a dihydric low molecular-weight alcohol as an arbitrary component:
wherein in the general formula(I), a letter p denotes an integer ranging from 0 to 2.
In a second aspect, the present invention provides a thermal recording material in accordance with the first aspect of the invention, wherein the polyhydric alcohol which is the trihydric or more alcohol as the essential component is represented by a following general formula (II):
wherein in the general formula(II) a letter n denotes an integer ranging from 0 to 9, and R
1
and R
2
that may be present in n types are, independently of one another, a hydroxymethyl or an alkyl group having from 1 to 8 carbon atoms.
In a third aspect, the present invention provides a thermal recording material in accordance with the first aspect of the invention, wherein the condensation reaction product as the essential component is obtained by using the 4-hydroxybenzoic acid at a mole fraction ranging from 1 to 150, another monocarboxylic acid at a mole fraction ranging from 0 to 50, the dicarboxylic acid at a mole fraction ranging from 0 to 1, the trihydric or more alcohol at a mole fraction ranging from 1 to 50, and the dihydric low molecular-weight alcohol at a mole fraction ranging from 0 to 50.
In a fourth aspect, the present invention provides a thermal recording material in accordance with the second aspect of the invention, wherein a letter n denotes ranging from 1 to 9, and R
1
and R
2
are hydroxymethyl, in which the trihydric or more alcohol is polypentaerythritol.
In a fifth aspect, the present invention provides a thermal recording material in accordance with the second aspect of the invention, wherein a letter n denotes ranging from 1 to 9, and R
1
and R
2
are ethyl, in which the trihydric or more alcohol is polytrimethylol propane.
DESCRIPTION OF THE PREFERRED EMBODIMENT
These and other objects and features of a thermal recording material in accordance with the present invention will become more apparent from the following detailed description.
Materials utilized for condensation reaction in accordance with
Akutsu Mitsuo
Mori Takahiro
Ohya Keiji
Shigeno Koichi
Tominaga Nobuhide
Asahi Denka Kogyo K.K.
Hess Bruce H.
Nixon & Vanderhye P.C.
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