JPH05193270A - Reversible thermosensitive recording material - Google Patents

Abstract

(57) [Summary] [Purpose] In a thermosensitive recording material that reversibly changes between a transparent state and an opaque state depending on temperature, it is possible to obtain a stable transparent state by widening the temperature range of the transparentizing temperature range. .. In a reversible thermosensitive recording material in which an organic low molecular weight compound is dispersed in a polymer resin matrix, A) an alicyclic ketone having 10 or more carbon atoms or its oxime or semicarbazone and B) carbon are used as the low molecular weight compound. An aliphatic saturated dicarboxylic acid of several 12 or more is used together. This material is applied onto the card substrate 1 to form the recording material layer 3. [Effect] The temperature range for making transparent is about 40 ° C. or more, and the temperature control of the heating means during printing / erasing is extremely easy
A stable transparent state can be obtained even if there is some temperature fluctuation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material capable of repeatedly displaying and erasing a visible image, and more particularly to a recording material suitable for performing visible recording on a commuter pass, entrance permit, various prepaid cards and the like. Regarding

[0002]

2. Description of the Related Art As a reversible thermosensitive recording material, a material in which an organic low molecular weight compound is mixed and dispersed in a polymer resin base material has been proposed (JP-A-55-154198). This material has the property of becoming transparent when cooled from a specific temperature range T ₁ to room temperature and becoming cloudy when cooled to a room temperature from a temperature range T ₂ higher than T _1. Can be reversibly printed and erased.

[0003]

However, this material has a problem that the temperature control for printing and erasing is very difficult because the temperature range T ₁ for making transparent is very narrow.

[0004]

The present invention is intended to solve the above-mentioned problems, wherein A) an alicyclic ketone having 10 or more carbon atoms is used as an organic low molecular weight compound dispersed in a polymer resin matrix. Or at least one oxime or semicarbazone derived therefrom, and B) having 1 carbon atom
It is characterized in that at least one of two or more aliphatic saturated dicarboxylic acids is used in combination.

By using these two kinds of organic low molecular weight compounds in combination, a recording material having a wide temperature range T ₁ for transparency can be obtained.

The present invention will be described below with reference to the drawings. FIG. 1 is a front view of an example of a card using the recording material of the present invention,
FIG. 2 is a ZZ sectional view thereof.

The polymer resin matrix in the present invention includes:
As long as it is a transparent and good film-forming resin, polyvinyl chloride, vinyl chloride copolymer such as vinyl chloride-vinyl acetate copolymer, polyvinylidene chloride, vinylidene chloride copolymer, polyester, polyamide, polystyrene, polymethyl (Meth) acrylate or its copolymer is preferable.

Examples of the organic low molecular weight compound to be dispersed in these polymer resin base materials include A) alicyclic ketone having 10 or more carbon atoms, or at least one oxime or semicarbazone derived therefrom, and B) carbon. Number 12
At least one of the above aliphatic saturated dicarboxylic acids is used in combination. As a result, the width of the transparent temperature range can be expanded and the temperature control for printing and erasing can be facilitated.

Examples of the alicyclic ketone having 10 or more carbon atoms as the component A include cyclodecanone, cycloundecanone, cyclododecanone, cyclotridecanone, cyclotetradecanone, cyclopentadecanone, cyclohexadecanone, cyclooctadecanone. , Cyclononadecanone, cycloeicosanone, cyclodocosanone, cyclotricosanone, cyclopentacosanone, cyclohexacosanone, cyclononacosanone and the like. Also, oximes or semicarbazones derived from these alicyclic ketones can be used.

Examples of the aliphatic saturated dicarboxylic acid having 12 or more carbon atoms as the component B include dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, eicosanedioic acid. Acids, heneicosanedioic acid, docosanedioic acid, tricosanedioic acid, tetracosanedioic acid, hexacosanedioic acid, triacontanedioic acid, tetratriacontanedioic acid and the like.
In addition to these, other organic low molecular weight compounds disclosed in JP-A-55-154198 may be used in combination.

As for the mixing ratio of each component, the ratio of the B component to the A component A: B is 98: 2 to 30:70, particularly 90: 1.
The range of 0 to 50:50 is preferable.

This recording material becomes transparent when heated at a temperature T ₁ by a heating means such as a thermal head, a heating stamp, and a heating roll. Next, if this transparent recording material is locally heated to a temperature T ₂ higher than T ₁ by a thermal head, a heating stamp, etc., only the heated portion becomes opaque (cloudy) and a visible image is displayed. can do. In order to erase the image, heating to the temperature range T ₁ may be performed again.

The width of the transparentized temperature range T ₁ is 5 ° C.
Stable transparent state is hardly obtained because of the difficulty to control the temperature of the heating means such as a thermal head is less than, also when he 60 ° C. or higher, excessively high temperature T ₂ to be printed, the thermal recording materials due to repeated printing and erasing Although the deterioration tends to proceed, according to the present invention, a temperature range of, for example, about 40 ° C. can be easily obtained.

FIG. 1 and FIG. 2 show a card which is one example of the use of the recording material of the present invention. A synthetic resin sheet such as polyethylene terephthalate (PET) or paper is used as a base material 1, and its base material 1 is used. A reflective layer 2, a recording material layer 3, a protective layer 4, and a print layer 5 for forming a visible recording display window 6 are laminated on the surface. A magnetic recording layer 7 and a protective layer 8 are provided on the back surface.

The reflective layer 2 is for making the image formed on the recording material layer 3 easy to see, and is preferably a vapor deposition layer or foil of aluminum, tin, or the like, or a paint layer mixed with metal powder.

The protective layer 4 is for preventing thermal deterioration of the recording material layer 3, and is made of PET, polyetherimide, polyetheretherketone, polysulfone, polyphenylene sulfide, polyarylate, polyether sulfone, polycarbonate, polyethylenena. Phthalate,
A film or coating film of a transparent resin having high heat resistance such as polyimide or acrylic resin can be used.

This card can be used as a prepaid card for entrance, shopping, rental, etc.,
By visually displaying the used amount and the remaining amount with magnetic recording and the like on the recording material layer 3 each time the device is used, it is possible to always know the accurate remaining amount.

[0018]

【Example】

(Example) Aluminum was vapor-deposited as a reflective layer on the surface of a PET sheet having a thickness of 188 μm and a magnetic recording layer having a thickness of 10 μm previously formed on the back surface. On top of that, vinyl chloride
Vinyl acetate copolymer (MRP-TS manufactured by Nisshin Chemical Co., Ltd.) 10
A recording material obtained by adding 35 parts by weight of cycloeicosane (having 20 carbon atoms) as an A component and 15 parts by weight of 1,12-tetradecanedioic acid (having 14 carbon atoms) as a B component to 0 parts by weight of an organic low-molecular compound It was dissolved in tetrahydrofuran, applied, and dried to form a recording material layer having a thickness of 10 μm.

On top of that, PE having a thickness of 2 μm is used as a protective layer.
A T film was attached, and printing for forming a visible recording display window was further performed. On the other hand, a protective layer was provided on the magnetic recording layer on the back surface, and punched into a card shape.

Comparative Example A card was prepared in the same manner as in Example except that only 35 parts by weight of cycloeicosane as the component A was used as the organic low molecular weight compound.

Then, each of the obtained cards is heated from 50 ° C. to 1
The sample was heated to 20 ° C. at 1 ° C. intervals, and the reflection density of the recording material at each temperature was measured with a Macbeth reflection densitometer RD-914.

The transparent temperature range T ₁ and its temperature range were determined by setting the measured value to 0.5 or less as an opaque state and 1.0 or more as a transparent state. The results are shown in Table 1.

[0023]

[Table 1] In the examples using the recording material of the present invention, it can be seen that the temperature range of the clearing temperature T ₁ is wide and a stable transparent state can be obtained even if the heating temperature fluctuates somewhat. On the other hand, in the comparative example containing only the component A, it is found that it is extremely difficult to obtain a transparent state when the transparency temperature is only 60 ° C.

Further, the recording material layer of the card of the embodiment is 85 ° C.
After heating to 0 ° C., it was cooled to room temperature to become transparent, and characters were printed with a thermal head at a printing energy of 1.3 J / cm ² . When these were heated to a temperature within the transparentization temperature range, the characters were erased, and the same visibility was obtained even if this was repeated 1000 times.

[0025]

INDUSTRIAL APPLICABILITY The recording material of the present invention has a wide transparent temperature range, and therefore, a stable transparent state can be obtained even if the heating temperature changes, and a visible image that can be repeatedly printed / erased is displayed on a pay card or the like. Suitable for

[Brief description of drawings]

FIG. 1 is a front view showing an example of a card using the recording material of the present invention.

FIG. 2 is a sectional view taken along line ZZ in FIG.

[Explanation of symbols]

 1 Base Material 2 Reflective Layer 3 Recording Material Layer 4 Protective Layer

Claims (1)

[Claims] 1. A reversible thermosensitive recording material comprising an organic low molecular weight compound dispersed in a high molecular resin matrix, which reversibly changes between a transparent state and an opaque state depending on temperature. A reversible combination of an alicyclic ketone having 10 or more carbon atoms, or at least one oxime or semicarbazone derived therefrom, and B) at least one aliphatic saturated dicarboxylic acid having 12 or more carbon atoms. Sensitive recording material.