JP3689176B2 - Reversible thermosensitive recording material composition and prepaid card using the same - Google Patents

Description

【００４５】
表１から分かるように、２種の結晶性低分子化合物の相溶性指数の差が０．３１より大きく、かつ、Ｔ_ｇ２＜Ｔ_ｃ１≦Ｔ_ｃ２＜Ｔ_ｇ１の関係を満足する実施例１〜実施例３は良好なネガ型記録特性を示す。一方、上記条件を満足しない比較例１〜３は不透明化（白濁化）する温度範囲が狭くなり消去性が低下し、比較例４〜６は記録不能であり、比較例７はポジ型でネガ型の記録は不可能であった。
【００５０】
【発明の効果】
以上説明したように、本発明による可逆性感熱記録材料組成物を用いれば、従来とは逆のネガ型記録が可能となり、従って視認性が向上し、よりペーパーライクなプリペイドカードが実現できる。
【図面の簡単な説明】
【図１】本発明の感熱記録材料組成物の示差熱分析結果を示す線図である。
【図２】本発明の感熱記録材料組成物に用いた結晶性低分子化合物の示差熱分析結果を示す線図である。
【図３】本発明の感熱記録材料組成物の静特性を示す線図である。
【図４】本発明の感熱記録材料組成物を利用したカードの斜視図である。
【図５】本発明の感熱記録材料組成物を利用したカードの断面図である。
【符号の説明】
１ カード基材
２ 反射層
３ 感熱記録層
４ 保護層
５ 印刷層
６ 可視記録表示部
７ 磁気記録層
８ 保護印刷層[0001]
BACKGROUND OF THE INVENTION
The present invention uses a reversible thermosensitive recording material composition, particularly a reversible thermosensitive recording material composition capable of repeatedly displaying and erasing a visible image by a negative recording method opposite to the conventional one, and such a reversible thermosensitive recording material composition. Related to prepaid cards.
[0002]
[Prior art]
The commuter pass for the transportation period, admission permit to the event venue and building, etc. are used repeatedly every day, but there is no way to check for illegal boarding or unauthorized entry for administrative purposes. In recent years, a check method using a magnetic card is being adopted in some cases, but since the recorded contents to be checked cannot be visually checked, there is a risk of check omission due to trouble on the device, and both the administrator and the user feel inconvenienced. It was.
[0003]
Also, in various prepaid cards, magnetic cards and IC cards are used, but since the recorded contents cannot be directly visually checked, it is not possible to easily check the payment amount or the remaining amount, which is inconvenient in terms of guaranteeing the contents to the user. there were.
[0004]
As a measure to improve this, there is a recording material that has a reversible thermosensitive recording layer for visual recording on commuter passes, admission tickets, various prepaid cards such as prepaid cards, etc., and to erase them. It has been. As the recording method, for example, a recording material in which an organic low molecular weight substance is dispersed in a polymer resin base material is used, and the recording layer is made transparent in a specific temperature region by heating, and the temperature is further increased. There is known a method (Japanese Patent Laid-Open Nos. 54-119377 and 55-154198) which comprises a step of heating and whitening the recording layer, and information can be read visually by the difference in contrast. It has been. Since these recording materials have a very narrow temperature range showing high light transmittance, they are difficult to be transparent, and there is a problem that temperature control for printing and erasing is very difficult. In order to solve this problem, there is a recording material (Japanese Patent Laid-Open No. 2-1363) using one or more kinds of aliphatic saturated dicarboxylic acid as an organic low molecular weight compound. The recording characteristics show that the film becomes transparent and is heated and then cooled to make it opaque (white turbidity). Therefore, a positive recording system is employed in which the entire recording material is erased (transparent) by heating at a low temperature with a stamp or roll, and is printed (opaque or clouded) by heating with a thermal head. Therefore, printing is performed in white characters, and there is a problem in visual recognition.
[0005]
[Problems to be solved by the invention]
As described above, the conventional technology has a problem that the temperature range showing a high light transmittance is very narrow, so that it is difficult to make transparent and temperature control of printing and erasing is very difficult, and printing is performed in white. As a result, there was a visual problem.
[0006]
The present invention solves the above-mentioned conventional problems, is easy to control the temperature for printing and erasing, is capable of negative recording, and is a reversible thermosensitive recording material composition excellent in visibility and such a composition. An object of the present invention is to provide a prepaid card that can be used repeatedly, using the heat-sensitive recording material composition.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the thermosensitive recording material composition according to the present invention includes a case where two types of crystalline low molecular weight compounds are mixed and dispersed in a polymer resin matrix and cooled from the first temperature region T _1. In the reversible thermosensitive recording material composition in which the light transmittance changes when cooled from the second temperature region T ₂ higher than T ₁ , the two kinds of crystalline low molecular compounds are represented by the following formula (1) and (2) is satisfied at the same time;
[0008]
| S ₁ -S ₂ |> 0.31 (1)
[0009]
[Equation 8]
T _g2 <T _c1 ≦ T _c2 <T _g1 (2)
Where S ₁ and S ₂ represent the compatibility index (S) of each of the two types of crystalline low molecular weight compounds to the polymer resin matrix, and the compatibility index S is included in the polymer resin matrix. When the amount of heat required to melt all the crystals of the dispersed crystalline low molecular weight compound is ΔH _m and the amount of heat necessary to melt the same crystalline low molecular weight compound alone is ΔH _M , [0010]
[Equation 9]
S = 1− (ΔH _m / ΔH _M ) (3)
T _g1 and T _g2 are the polymer resin base materials when the reversible thermosensitive material composition is heated to the first temperature region T ₁ and the second temperature region T ₂ and then cooled. T _c1 and T _c2 are glass transition temperatures, respectively, and the polymer resin mother when the reversible thermosensitive material composition is heated to the first temperature region T ₁ and the second temperature region T ₂ and then cooled. It is the extrapolation crystallization start temperature of the compound showing the lowest crystallization temperature among the crystalline low molecular weight compounds dispersed in the material.
[0015]
Here, the reversible thermosensitive material composition becomes opaque when cooled from the first temperature range T ₁ and becomes transparent when cooled from the second temperature range T ₂ .
[0016]
The prepaid card according to the present invention is characterized in that a magnetic recording layer and a thermosensitive recording layer comprising the above-described reversible thermosensitive recording material composition are provided on a resin substrate.
[0017]
Here, the magnetic recording layer is provided on one surface of the resin base material, and the thermosensitive recording layer is provided on the other surface via a reflective layer, and a protective layer is formed on the thermosensitive recording layer. However, it is preferable that the printing layer which has an opening part is provided on this protective layer.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Conventionally, in order to solve the above-mentioned problems, investigations have been made by paying attention to the kind of resin base material, the composition or the kind of low molecular compound to be dispersed therein, the melting point, etc. Paying attention to the compatibility of the low molecular weight compound dispersed in it, the compatibility index is defined as the compatibility index S of the low molecular weight compound dispersed with the resin matrix, and the relationship between the compatibility index S and the recording characteristics is examined. did. Here, the compatibility index S is the amount of heat required to melt all crystals of the crystalline low molecular compound dispersed in the polymer resin matrix, ΔH _m , and the same amount of the same crystalline low molecular compound alone. when the amount of heat required to melt was ΔH _M, the following formula [0019]
[Formula 13]
S = 1− (ΔH _m / ΔH _M ) (3)
It is prescribed by. More specifically, when a reversible thermosensitive recording material composition is heated at a heating rate of 10 ° C./min using a differential thermal scanning calorimeter, the crystalline low molecular weight compound dispersed in the base material [Delta] H the amount of heat needed to melt the whole crystals _m, when the amount of heat required to melt the crystalline low molecular compound alone equal volume are not dispersed in a polymer resin matrix in was [Delta] H _M, the phase The solubility index S is defined by equation (3). 1 and 2 show the results of differential thermal analysis of the reversible thermosensitive material composition and the crystalline low molecular weight compound. The areas of the respective peaks in FIGS. 1 and 2 are ΔH _m and ΔH _M , respectively. Further, the present inventors also pay attention to the glass transition temperature Tg of the resin matrix after dispersing the crystalline low molecular weight compound and the crystallization temperature Tc of the dispersed crystalline low molecular weight compound, and Tg, Tc and recording characteristics. We studied earnestly about the relationship.
[0020]
And when there are two kinds of crystalline low molecular compounds dispersed in the resin base material,
[0021]
| S ₁ -S ₂ |> 0.31 (1)
[0022]
T _g2 <T _c1 ≦ T _c2 <T _g1 (2)
At the same time,
[0024]
A reversible thermosensitive recording material composition that becomes white turbid after cooling at a low temperature and becomes transparent after cooling at a high temperature, and has a wide temperature range that can be made opaque and a wide temperature range that can be made transparent. I found.
[0025]
However, if S ₁ and S ₂ are the two crystalline low molecular compound, represents a compatibility index to each of the polymer resin matrix (S), T _g1 and T _g2 are respectively the reversible thermosensitive material When the composition is heated to the first temperature region T ₁ and the second temperature region T ₂ and then cooled, the glass transition temperature of the polymer resin base material, T _c1 and T _c2 are reversible thermosensitive material compositions, respectively. Of the compound exhibiting the lowest crystallization temperature among the crystalline low molecular weight compounds dispersed in the polymer resin matrix when heated to the first temperature region T ₁ and the second temperature region T ₂ and then cooled. Extrapolation crystallization start temperature.
[0026]
The weight ratio of the polymer resin matrix / crystalline low molecular compound is preferably 95/5 to 25/75, and more preferably 85/15 to 50/50. When there are more resin base materials than 95/5, it will not become cloudy by low temperature heating, and contrast will fall. Moreover, when there are more crystalline low molecular compounds than 25/75, film forming property will be inferior.
[0027]
FIG. 3 shows the static characteristics of the reversible thermosensitive recording material composition according to the present invention. As shown, it decreases the reflection density cooling after heating temperature range T _1, that is opacified, cloudy. When cooled after heating in a higher temperature range T ₂ , it becomes transparent. Therefore, when this composition is used, the entire recording material is erased (opaque or white turbid) by heating at low temperature with a stamp or roll, and the recording material is made transparent by partially heating it with a thermal head. Is possible. For example, when a black base material is used for the base of the recording layer, a paper-like recording material capable of black printing on a white background can be realized.
[0028]
FIG. 4 is a perspective view of an example of a card using the reversible thermosensitive recording material composition according to the present invention as a recording layer, and FIG. 5 is a sectional view thereof. 4 and 5 show an admission ticket as an example. A known reflective layer 2, a recording layer 3 made of a reversible thermosensitive recording material composition, a transparent protective layer 4 and a printing layer 5 are sequentially laminated on the surface of a synthetic resin substrate sheet 1 such as polyethylene terephthalate. Necessary information is printed on the surface of the printing layer 5, and a visible recording display window 6, which is a window for viewing the recorded contents recorded on the recording layer 3, is opened. A magnetic recording layer 7 and a protective printing layer 8 are laminated on the back surface of the synthetic resin base sheet 1.
[0029]
In this card, when the recording area corresponding to the visible recording display window 6 of the recording layer 3 is heated and cooled in the temperature area T ₁ shown in FIG. 3 by heating means such as a heat stamp or a heating roll, the recording area becomes opaque. (White turbidity, elimination). Then the recording means such as a thermal head is heated and cooled only display text portion of the recording area in the temperature range T ₂ of the 3, only the display character part is transparent, the contrast between the opaque part and the transparent part, visually The recorded information can be read. If the opacity (white turbidity) temperature T ₁ is low, the storage stability is lowered. If the temperature range of T ₁ is narrow, the opacity (white turbidity) temperature range is narrowed and the erasability is lowered. On the other hand, if T ₂ is too high, damage to the recording material at the time of printing and erasing becomes large, and durability is lowered. Accordingly, T ₁ is desirably 80 to 150 ° C. and T ₂ is desirably 120 to 170 ° C. However, T ₁ and T ₂ do not substantially overlap.
[0030]
In the present invention, the polymeric resin matrix constituting the recording layer includes polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-vinyl acetate-alcohol copolymer. Polymers, other vinyl acetate compounds, vinyl chloride copolymers, polyvinylidene chloride, vinylidene chloride copolymers, pyresters, polyamides, polystyrene, polymethyl (meth) acrylate, or copolymers thereof are preferred.
[0031]
Examples of the combination of the crystalline low molecular weight compound dispersed in the resin matrix include a combination of a fatty acid ester composed of a fatty acid and cholesterol and an aliphatic dibasic acid, and a typical fatty acid ester composed of a fatty acid and cholesterol is capric acid. Examples thereof include cholesterol, cholesterol laurate, cholesterol, myristic acid cholesterol, palmitic acid cholesterol, stearic acid cholesterol, behenic acid cholesterol, and lignoceric acid cholesterol. Representative aliphatic dibasic acids include aliphatic dibasic acids such as adipic acid, suberic acid, azelaic acid, and sebacic acid.
[0032]
By changing the mixing ratio of the crystalline low molecular weight compound dispersed in the resin base material, the temperature at which it becomes transparent and opaque (white turbidity) can be freely changed. This mixing ratio is appropriately set in consideration of the performance of the printing / erasing device, the sharpness of printing contrast, and the like. Furthermore, the combination of the crystalline low molecular compounds dispersed in the resin base material is not limited to the above-described combinations, and in the case of two types, if the formulas (1) and (2) are satisfied at the same time, other crystalline low molecular compounds But there is no problem.
[0033]
As the protective coating, a resin having high heat resistance such as polyethylene terephthalate, polyether imide, polyether ether ketone, polysulfone, polyphenylene sulfide, polyacrylate, polyether sulfone, polycarbonate, polyethylene naphthalate, polyimide, and acrylic resin is preferable.
[0034]
The reflective layer is preferably a vapor-deposited layer such as aluminum or tin, or a paint mixed with foil or aluminum fat.
[0035]
【Example】
Example 1
Aluminum was vapor-deposited as a reflective layer on the surface of a 188 μm-thick polyethylene terephthalate resin film previously coated with a magnetic paint as a magnetic recording layer to a thickness of 10 μm, and the recording layer was coated thereon to a thickness of 10 μm. As a polymer resin base material and a crystalline low-molecular compound constituting the thermosensitive recording layer,
Vinyl chloride-vinyl acetate-vinyl alcohol copolymer 60 parts by weight Cholesterol stearate [C _17H35 CO 2 _C25 H ₄₇ ] 25 parts by weight Adipic acid [HO _2C (CH ₂ ) ₄ CO _2H ] 15 parts by weight were dissolved in tetrahydrofuran. It apply | coated on the aluminum vapor deposition layer, and it heat-dried and made it 10 micrometers in thickness. A 2 μm thick polyethylene terephthalate resin protective film was affixed thereon. A printed layer having a visible recording display window as an opening was formed by printing on the heat-sensitive recording layer side of the card substrate thus obtained. Further, a protective printing layer was provided on the magnetic recording layer side, and then punched into a card mold to produce a card of the present invention.
[0036]
Example 2
A card was produced in the same manner as in Example 1 except that the adipic acid in Example 1 was changed to suberic acid [HO _2C (CH ₂ ) ₆ CO _2H ].
[0037]
Example 3
A card was produced in the same manner as in Example 1 except that the adipic acid in Example 1 was changed to sebacic acid [HO ₂ C (CH ₂ ) ₈ CO ₂ H].
<< Comparative Example 1 >>
A card was produced in the same manner as in Example 1 except that the adipic acid of Example 1 was changed to dodecanoic acid [HO ₂ C (CH ₂ ) ₁₀ CO ₂ H].
[0038]
<< Comparative Example 2 >>
A card was produced in the same manner as in Example 1 except that the adipic acid in Example 1 was changed to tetradecanoic acid [HO ₂ C (CH ₂ ) ₁₂ CO ₂ H].
[0039]
<< Comparative Example 3 >>
A card was produced in the same manner as in Example 1 except that the adipic acid of Example 1 was changed to hexadecanoic acid [HO ₂ C (CH ₂ ) ₁₄ CO ₂ H].
[0040]
<< Comparative Example 4 >>
A card was produced in the same manner as in Example 1 except that the adipic acid of Example 1 was changed to octadecanedioic acid [HO ₂ C (CH ₂ ) ₁₆ CO ₂ H].
[0041]
<< Comparative Example 5 >>
A card was produced in the same manner as in Example 1 except that the adipic acid in Example 1 was changed to eicosane diacid [HO ₂ C (CH ₂ ) ₁₈ CO ₂ H].
[0042]
<< Comparative Example 6 >>
A card was produced in the same manner as in Example 1 except that the adipic acid of Example 1 was changed to cholesterol palmitate [C ₁₅ H ₃₁ CO ₂ C ₂₅ H ₄₇ ].
[0043]
<< Comparative Example 7 >>
In the same manner as in Example 1, the polymer resin base material constituting the recording layer and the low molecular compound were vinyl chloride-vinyl acetate-vinyl alcohol copolymer 60 parts by weight behenic acid [C ₂₁ H ₄₃ CO ₂ H] 25 parts by weight. 15 parts by weight of dodecanedioic acid [HO ₂ C (CH ₂ ) ₁₀ CO ₂ H] About these examples and comparative examples, heating is performed at intervals of 1 ° C. from 50 ° C. to 150 ° C. Was measured with a Macbeth densitometer RD-914 to determine a clearing temperature range and a clouding temperature range. When the measured value is 0.5 or less, it is an opaque state (white turbid state), and 1.0 or more is a transparent state. The opaque reflection (white turbidity) temperature range, the transparent temperature range, and the opaque reflection (white turbidity) minimum reflection density and transparency. The maximum reflection density at the time was obtained. The results are shown in Table 1 together with the compatibility index of each crystalline low molecular weight compound.
[0044]
[Table 1]

[0045]
As can be seen from Table 1, the difference in compatibility index between the two crystalline low-molecular compounds is larger than 0.31 , and Examples 1 to 1 satisfying the relationship of T _g2 <T _c1 ≦ T _c2 <T _g1 Example 3 shows good negative recording characteristics. On the other hand, Comparative Examples 1 to 3, which do not satisfy the above conditions, have a narrow temperature range for opacification (white turbidity), resulting in poor erasability, Comparative Examples 4 to 6 cannot be recorded, and Comparative Example 7 is a positive type and negative. Mold recording was not possible.
[0050]
【The invention's effect】
As described above, when the reversible thermosensitive recording material composition according to the present invention is used, negative recording which is opposite to the conventional one can be performed, and thus visibility is improved and a paper-like prepaid card can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing the results of differential thermal analysis of the thermosensitive recording material composition of the present invention.
FIG. 2 is a diagram showing the results of differential thermal analysis of the crystalline low molecular weight compound used in the thermosensitive recording material composition of the present invention.
FIG. 3 is a diagram showing the static characteristics of the heat-sensitive recording material composition of the present invention.
FIG. 4 is a perspective view of a card using the heat-sensitive recording material composition of the present invention.
FIG. 5 is a cross-sectional view of a card using the heat-sensitive recording material composition of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Card base material 2 Reflective layer 3 Thermal recording layer 4 Protective layer 5 Print layer 6 Visible recording display part 7 Magnetic recording layer 8 Protective print layer

Claims (3)

In the polymer resin matrix , (A) a fatty acid ester composed of a fatty acid and cholesterol and (B) two crystalline low molecular compounds composed of an aliphatic dibasic acid having 6 to 10 carbon atoms are mixed and dispersed. when cooled from the temperature region T ₁ and, in the reversible thermosensitive recording material composition transmittance of light changes when the cooling from the T ₁ higher than the second temperature region T _2, wherein the two kinds of crystalline A reversible thermosensitive recording material composition wherein the low molecular weight compound simultaneously satisfies the following formulas (1) and (2);
| S ₁ -S ₂ |> 0.31 (1)
T _g2 <T _c1 ≦ T _c2 <T _g1 (2)
However, S ₁ and S ₂ are the represent two each of the polymer resin compatibility index to the base material of the crystalline low molecular compound (S), compatibility index S is a polymer resin base material When the amount of heat necessary for melting all the crystals of the dispersed crystalline low molecular weight compound is ΔH _m and the amount of heat necessary for melting the same crystalline low molecular weight compound alone is ΔH _M , S = 1− (ΔH _m / ΔH _M ) (3)
T _g1 and T _g2 are the values of the polymer resin base material when the reversible thermosensitive material composition is heated to the first temperature region T ₁ and the second temperature region T ₂ and then cooled. T _c1 and T _c2 are glass transition temperatures, respectively, and the polymer resin mother when the reversible thermosensitive material composition is heated to the first temperature region T ₁ and the second temperature region T ₂ and then cooled. It is the extrapolation crystallization start temperature of the compound showing the lowest crystallization temperature among the crystalline low molecular weight compounds dispersed in the material.   A prepaid card comprising a resin substrate and a magnetic recording layer and a thermosensitive recording layer comprising the reversible thermosensitive recording material composition according to claim 1. The magnetic recording layer is provided on one surface of the resin base material, the thermosensitive recording layer is provided on the other surface via a reflective layer, and a protective layer is provided on the thermosensitive recording layer. The prepaid card according to claim 2 , wherein a printed layer having an opening is provided on the protective layer.

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