JP3207528B2 - Reversible thermosensitive recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording material capable of repeatedly displaying and erasing a visible image, and more particularly to a recording material suitable for performing visible recording on commuter passes, admission certificates, various prepaid cards, and the like. About.

[0002]

2. Description of the Related Art As a reversible thermosensitive recording material, a material in which an organic low-molecular 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 to a normal temperature from a specific temperature range T ₁ and becoming cloudy when cooled to a normal 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 resin matrix deteriorates due to repeated thermal printing and thermal erasure, and the degree of white turbidity gradually decreases. It is also known to provide a protective layer on the recording material layer in order to reduce this problem, but the effect is still not sufficient because the protective layer needs to be as thin as possible.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to disperse an organic low-molecular compound in a polymer resin base material and to disperse an organic tin ester and an alkyl tin.
Sumercapto compound or alkyltin sulfide compound
A reversible thermosensitive recording material selected from the group consisting of a heat stabilizer for the polymer matrix, which reversibly changes between a transparent state and an opaque state depending on temperature, wherein the organic low-molecular compound has 15 carbon atoms. It is characterized by comprising the above higher ketone or a derivative thereof and an aliphatic saturated dicarboxylic acid having 12 or more carbon atoms.

According to the present invention, a polymer resin base material is made of vinyl chloride .
This is particularly effective when the resin is mainly composed of a polymer.

Hereinafter, the present invention will be described 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 cross-sectional view thereof.

[0007] As the polymer resin base material in the present invention,
Any resin may be used as long as it is transparent and has good film-forming properties, and polyvinyl chloride copolymers such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymer are preferred .

[0008] These polymer resin matrix organic low molecular weight compound dispersed in, have been proposed in various kinds of temperature control for the printing and erasing the range of temperature range T ₁ of clearing is narrow Is difficult, so that the clearing temperature range T
_As the broad one, the following two material systems are particularly suitable.

A) Combination system of higher fatty acid having 15 or more carbon atoms or its derivative (a ₁ ) and saturated aliphatic dicarboxylic acid having 12 or more carbon atoms (a ₂ ) B) Higher ketone having 15 or more carbon atoms or its combination Derivative (b
₁ ) and an aliphatic saturated dicarboxylic acid having 12 or more carbon atoms (b)
₂ ) Combined system with

[0010] As the material system a _1-component carbon number 15 or more higher fatty acid which is of the A, oleic acid, erucic acid, 15
-Tetracosenoic acid, tarrylic acid, 11-octadecynoic acid,
Palmitic acid, docosanoic acid, melicic acid, stearic acid, arachidic acid and the like. In addition, higher fatty acid derivatives such as esters, acid anhydrides, amides, hydroxy acids, and keto acids can also be used.

[0011] Examples of the aliphatic saturated dicarboxylic acid having 12 or more carbon atoms of a _2-component, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, nonadecanoic diacid, eicosane Examples include diacid, heneicosantioic acid, docosantioic acid, tricosandioic acid, tetracosantioic acid, hexacosantioic acid, triacontanedioic acid, and tetratriacontanedioic acid.

[0012] The mixing ratio of each component, at least one of 98 to 30 of a _1, in particular 90 to 50, at least one of 2 to 70 of a _2, particularly well to use in a weight ratio of 10-50, thereby , The width of the clearing temperature range T ₁ is 20 ° C. or more,
In particular, the temperature can be 30 ° C. or higher.

[0013] 1 carbon atoms is b ₁ components of the material system of the B
As higher ketones of 5 or more, 8-pentadecanone, 9
-Heptadecanone, 10-nonadecanone, 11-heneicosanone, 12-trichosanone, 14-heptacosanone, 16-hentriacontanone, 18-pentatriacontanone, 22-tritetracontanone, 2-pentadecanone, 2-hexadecanone, 2- Heptadecanone,
2-octadecanone, 2-nonadecanone and the like can be mentioned.

Cyclopentadecanone, cyclohexadecanone, cyclooctadecanone, cyclononadecanone, cycloeicosanone, cyclodocosanone, cyclotricosanone, cyclopentacosanone, cyclohexacosanone, cyclononacosanone It may be an alicyclic ketone such as nonone. Further, oximes or semicarbazones derived from these higher ketones can also be used.

[0015] As b ₂ component can be the same as that of the a ₂ component mentioned above. The mixing ratio b ₁ / b ₂ of each component may be substantially the same as a ₁ / a _{2 of} A.

As the heat stabilizer, among the heat stabilizers added to prevent decomposition, deterioration and discoloration due to heat when a polymer resin base material is used for melt molding, those which do not impair transparency. Can be selected.

For example, when the resin base material is a resin mainly composed of vinyl chloride such as polyvinyl chloride or vinyl chloride-vinyl acetate copolymer, an organic tin ester such as dibutyltin malate or octyltin laurate; Thermal stabilizers such as alkyltin mercapto such as methyltin mercapto, dibutyltin mercapto, and octyltin mercapto; and alkyltin sulfides such as dibutyltin sulfide and octyltin sulfide.

[0018] The content of the heat stabilizer is usually 10
It is in the range of 1 to 15 parts by weight with respect to 0 parts by weight.

The mixture thus obtained is usually from 3 μm to
In order to form a thin film of about 20 μm, dissolved in a solvent,
Applied to the substrate.

When this recording material is heated at a temperature T ₁ by a heating means such as a thermal head, a heating stamp, a heating roll, or the like, the recording material becomes transparent. Next, this transparent recording materials, thermal head, do it like in and locally heated to a higher temperature T ₂ than T ₁ heating stamp, only the heated portion is opacified (cloudy), displaying a visible image can do. To erase the image, it may be heated to a temperature range T ₁ again.

The width of the transparent 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 is apt to progress, a temperature range of, for example, about 40 ° C. can be easily obtained with the recording material exemplified above.

Further, by including a heat stabilizer in the recording material, a clear image can be obtained with a small decrease in turbidity even if thermal printing and thermal erasure are repeated.

FIG. 1 and FIG. 2 show a card which is an example of use of the recording material of the present invention. The card 1 is made of a synthetic resin sheet such as polyethylene terephthalate (PET) or paper as a base material 1. On the surface, a reflective layer 2, a recording material layer 3, a protective layer 4, and a printed layer 5 for forming a visible recording display window 6 are laminated. 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 deposited layer or foil of aluminum, tin or the like, or a paint layer mixed with metal powder.

The protective layer 4 is preferably provided to further prevent the thermal deterioration of the recording material layer 3. PET, polyetherimide, polyetheretherketone, polysulfone, polyphenylenesulfide, polyarylate, polyethersulfone, A film or coating of a transparent resin having high heat resistance such as polycarbonate, polyethylene naphthalate, polyimide, and acrylic resin can be used.

This card can be used, for example, as a prepaid card for entrance, shopping, rental, etc.
By displaying the amount of money used and the balance together with the magnetic recording and the like on the recording material layer 3 at each use, an accurate balance can always be known.

[0027]

【Example】

(Example 1) Aluminum was vapor-deposited as a reflective layer on the surface of a 188-μm-thick PET sheet in which a magnetic recording layer was previously formed to a thickness of 10 μm on the back surface.

Further, based on 100 parts by weight of a vinyl chloride-vinyl acetate copolymer (MRP-TS manufactured by Nissin Chemical Co., Ltd.),
35 parts by weight of 12-tricosanone and 15 parts by weight of 1,12-tetradecandioic acid are added as an organic low molecular compound, and 5 parts by weight of dibutyltin mercapto (Stan JF-95B manufactured by Sankyoki Gosei Co., Ltd.) is further added as a heat stabilizer. The added recording material was dissolved in tetrahydrofuran, applied, and dried to form a recording material layer having a thickness of 10 μm.

On top of that, a 2 μm-thick PE is formed as a protective layer.
A T-film was attached, and printing was performed to form a visible recording display window. On the other hand, a protective layer was provided on the magnetic recording layer on the back surface, and punched into a card shape.

[0030]

Comparative Example A card was prepared in the same manner as in Example 1 except that no heat stabilizer was added.

Then, each of the obtained cards is heated from 50 ° C. to 1
The recording material 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 measured value is an opaque state 0.5 or less, also called for clearing temperature range T ₁ and its temperature range above 1.0 as a transparent state. Table 1 shows the results. Also, printing was performed with a thermal head at an applied energy of 1.3 joules / cm ² , and the operation of erasing with a heating stamp at 80 ° C. was repeated. It is shown in FIG.

[0034]

[Table 1]

[0035] In the present invention recording Example 1 material with the heated printing, it does not decrease opacity even after repeated erasure, can withstand multiple repeated use. On the other hand, in the comparative example containing no heat stabilizer, the degree of white turbidity gradually decreased, and the number of uses at which the same image clarity as the first time was obtained was low.

[0036]

According to the recording material of the present invention, the turbidity of the image does not decrease even when heating printing and erasing are repeated, and a clear image can be obtained even after repeated use.

[Brief description of the 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 the line ZZ in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Reflective layer 3 Recording material layer 4 Protective layer

Claims (1)

(57) [Claims] An organic low molecular weight compound is dispersed in a vinyl chloride copolymer base material, and an organic tin ester and an alkyl
Sumercapto compound or alkyltin sulfide compound
A reversible thermosensitive recording material selected from the group consisting of a compound containing a heat stabilizer for the polymer base material and reversibly changing between a transparent state and an opaque state with temperature, wherein the organic low-molecular-weight compound has 15 carbon atoms. A reversible thermosensitive recording material comprising the above higher ketone or a derivative thereof and an aliphatic saturated dicarboxylic acid having 12 or more carbon atoms.