JPH0433884A - Information recording material - Google Patents

Abstract

PURPOSE:To enable repeating recording and erasing with low energy and in a short time by constituting an information recording material in such manner that the information recording material is mainly composed of a high-molecular organic substance and the glass-transition temperature of the recording material has a specific temperature region and the storage elastic modulus and loss tangent of the material are within a specific range. CONSTITUTION:Stress is applied to a recording material 1 having a smooth surface by a metal mold 3 having an irregular shape at a temperature T1 exceeding a glass-transition temperature (Tg) to give distortion. Then, the recording material is cooled to a temperature T0 lower than Tg so that the distortion is fixed. When temperature is elevated again to T2 by a heating mean 4 under conditions where no pressure is applied or such low pressure as giving no substantial deformation is applied, the surface of the recording material recovers from the distortion and returns to the original smooth surface. When this principle is applied, the distortion is given in the temperature region higher than the glass-transition temperature (Tg) and is fixed in that lower than Tg. Therefore, Tg is required to be within the range of 50-140 deg.C. Also the recording material is required to have an appropriate elastic modulus E-, which is within the range from 6X10<6> dynes/cm<2> to 1X10<8> dynes/cm<2> at a temperature 30 deg.C higher than Tg. Further, the recording material is restricted by the value of a loss tangent tandelta in the temperature region from the temperature region from the temperature, where the distortion is given, to Tg and the value of tandelta in the temperature region from Tg to the temperature 30 deg.C higher than Tg is required to be not less than 0.15.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a recording material that can be applied to information recording cards, which can be visually recognized, and can be repeatedly recorded and erased. It relates to information recording materials.

(Prior art) Information records with a memory function used in telephones, ticket vending machines and ticket gates in transportation facilities, automatic cash dispensers in financial institutions, and various other vending machines (hereinafter referred to as "vending machines, etc.") Cards with layers are widely contradictory.

Among these, there are many cases where it is required to be able to visually recognize the card user or the business providing the service etc. through the vending machine or the like, the usage status, transaction details, etc.

Conventionally, as methods for recording visible information that can be applied to cards, methods have been put into practical use, such as a method of printing each time a card is used, and a method of notifying an approximate value of the remaining amount used by punching a hole. However, with this method, the amount of information that can be recorded is limited because it is impossible to erase the records, and there is a limit to the amount of information that can be recorded.
This was extremely inconvenient for cards that require accurate recognition of balances, etc.

Therefore, there is a demand for something that can erase and rewrite the contents recorded on cards as needed.

As a recording method that can meet this demand, there is a method that utilizes the so-called shape memory phenomenon of plastics. This shape memory phenomenon refers to plastic that has been molded so that no strain remains, is deformed at a temperature above the glass transition temperature, and then cooled to fix the strain. After that, if the material is heated again to a temperature above the glass transition temperature without applying stress, it will return to its original, undistorted shape.

Utilizing this phenomenon, a smooth image can be formed on the frosted surface by applying a frost (rough surface) with distortion to the recording material and restoring all or part of the distortion to make it smooth. We proposed a method in which a frost image is formed on a smooth surface and records are repeatedly written and erased.

(Problems to be Solved by the Invention) When the method using the shape memory phenomenon described above is put to practical use as a method for recording information on the aforementioned cards, a pressure device having a heat source, such as a solenoid, is used to apply distortion. A pressurizing device, a pressurizing device using an air cylinder or a hydraulic cylinder, a pressurizing device using a cam, etc. are required, and a heating device such as a thermal head, thermal stamp, racer beam generator, etc. is required to recover the distortion. is required.

When these devices are incorporated into the above-mentioned vending machines and the like, in many cases, the capacity of the heat source and pressurizing device must be reduced due to space constraints. Therefore, information recording materials that can be used in vending machines and the like are required to achieve their purpose with the minimum amount of thermal and physical energy.

In addition, users and businesses of vending machines, etc. often require quick response times, and it is desirable that the time required to write and erase information on recording materials be shorter. . However, in order to achieve clear visual recognition using the above-mentioned method, excessive pressure and heat are required, especially when applying distortion, and it takes a long time. It was difficult to put it into practical use.

(Means for Solving the Problems) The present invention has been made as a result of intensive studies to solve the above problems.
We have discovered a material that achieves the above objectives by applying energy in a short time and with minimal decoyment.The gist of this material is to create an information record mainly composed of organic polymeric substances provided on the surface of a support. The recording material has a glass transition temperature in the range of 50 to 140°C and a storage modulus of 6 at a temperature 30°C higher than the glass transition temperature.
It is in the range of X 106 to I
The loss tangent in the temperature range up to 0°C is 0°1.
5 or more.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a diagram showing an example of the temperature dependence of the viscoelastic properties of an organic polymer substance, and FIG. 2 is a cross-sectional view showing the principle of recording using the recording material of the present invention.

In ordinary polymer materials (especially non-grade polymers),
The temperature dependence of storage modulus (El) and loss tangent (tan δ) is as shown in FIG.

The principle of recording using this polymer substance will be explained with reference to FIG. 2. First, a recording material 1 having a smooth surface is provided on a support 2 as shown in FIG. 2(A).

As shown in (B), stress is applied to the recording material 1 at a temperature exceeding the glass transition temperature (Tg), for example, at a temperature of T1, to give a strain to the recording material 1 using a mold 3 having an uneven shape.

Then, as shown in (C), the temperature is lower than Tg, for example T, while the strain remains. Cool until cool.

Here, the strain imparted at T1 is fixed, exhibiting a frost-like appearance F, and the difference from the surrounding smooth surface can be visually recognized.

CD>, the heating means 4 is heated again to a temperature higher than Tg, and A L< is a temperature higher than T1, for example T2.
Under conditions where no pressure is applied or a pressure low enough to cause no substantial deformation is applied until the temperature rises, the previously applied strain is recovered and the surface returns to its original smooth surface.

Using this principle, for example, the frost surface can be selectively T
A transparent image can be formed on a frosted surface, or a frosted image can be formed on a transparent background, by heating the image to a temperature of 100% or selectively giving frost-like deformation at T1, and it can also be easily erased. Therefore, the change can be repeated many times.

The present invention utilizes such a principle to provide a recording material applicable to the above-mentioned vending machines, etc. According to the recording material of the present invention, the required pressure and heat amount can be minimized. The processing time can be significantly shortened compared to conventional methods. The reason why such an effect can be obtained will be explained step by step next.

It is the glass transition temperature (
Tg) or higher, and the strain is fixed at 1g.
The temperature range is as follows.

In the meantime, a preferable glass transition temperature range for use as a recording material in a stable state was determined, and the Tg of the polymeric substance usable in the present invention is in the range of 50 to 140°C. Materials whose Tg does not reach 50° C. lack storage stability of strain, and records may disappear or become less clear during storage, making them impractical.

If the Tg exceeds 140° C., not only will the amount of heat required for strain imparting and erasing become excessive, but also the support 2 of the card may be deformed, which is disadvantageous.

Next, the recording material in the present invention needs to have an appropriate modulus of elasticity in a limited temperature range.

The pressure required to apply strain is correlated with the elastic modulus of the material, and in order to apply strain at a lower pressure, it is sufficient to use a material with a low elastic modulus or in a temperature range where the elastic modulus is low. As shown in FIG. 1, in general polymeric materials, the storage modulus E- decreases with temperature, so it is considered preferable to apply strain at a higher temperature.

However, in a recording device that can be incorporated into a vending machine or the like, if strain is applied at a temperature much higher than Tg, cooling of the mold will become more difficult. Furthermore, if the storage elastic modulus E' is too low, stickiness may occur, causing serious trouble.

Therefore, the recording material of the present invention has an appropriate E in a limited temperature range.
It is necessary to have -.

Specifically, at a temperature 30°C higher than Tg, E- is 6 x 106 d y n7 cm2 or more, 1 x 108 d
It is necessary that it be within the range of yn/12 or less.

If the material does not reach 6 x 106 d yn/am", fusion will occur at the contact area of the recording device when strain is applied, causing permanent deformation of the recording material and deteriorating its repeatability. In the recording device, this causes contamination and causes inconveniences such as mechanical troubles.Furthermore, when recovering from distortion, if the method is carried out using a method that comes into contact with the recording material, such as a thermal head, the above-mentioned fusion method is used. There is a problem with the wear phenomenon.

Moreover, if E−1X10” dyn/cn+2 is exceeded, an excessive pressure is required to impart strain, which is not only impractical but also causes damage to the support 2 and other functional media (for example,
This is disadvantageous because it may also deform the magnetic recording layer (magnetic recording layer).

Furthermore, the recording material of the present invention is subject to restrictions during the cooling process to fix the applied strain. Originally, in order to completely fix the strain, the stress should not be removed after applying the strain, and the stress should be reduced to 1 g.
It is desirable to cool down to:

However, as mentioned earlier, in vending machines, etc., quick response is often required, and the application and fixation of distortion can be completed in an extremely short time (specifically, 1 second, 7 times or less). In reality, the stress will be removed before it is cooled down to 1 g or less. If this is not done, and the strain is recovered at the same time as the stress is removed, the strain will be incompletely fixed, making it impractical.

In order to achieve the object of the present invention, it is preferable to use a material that causes a delay in strain recovery.

The delay in strain recovery when the stress is removed is approximately the loss tangent t
It can be considered that there is a correlation with the value of andδ, and the larger the value, the greater the delay in distortion recovery.

The recording material in the present invention has a Tg from the temperature at which strain is applied.
The value of loss tangent tan δ in the temperature range up to
Must be 5 or more.

If there is a temperature in which tan δ is less than 0.15 in the temperature range, strain recovery will occur in an extremely short time after stress release,
Strain fixation is insufficient, resulting in poor visibility, or the temperature range in which strain can be sufficiently fixed becomes extremely narrow, making temperature control difficult and impractical.

Examples of organic polymer substances that have the above-mentioned viscoelastic properties and can be the main body of recording materials include (1) Vinyl polymers such as polyvinyl chloride, polystyrene, polymethyl methacrylate, etc. (2) Condensation polymers include polyester polymers and polyamide copolymers. (3) Examples of the addition type polymer include polyurethane copolymers, but are not limited thereto. In addition, in the present invention, methods of blending two or more types of polymers or blending low molecular weight substances such as plasticizers and petroleum resins for the purpose of adjusting viscoelastic properties are used.
It can be used suitably. According to this method, even if the above-mentioned viscoelastic properties cannot be obtained with a single polymer, they can be sufficiently utilized by selecting an appropriate modifier. Furthermore, depending on the material, it is also possible to take measures such as crosslinking to prevent fusion during strain recovery.

The recording material mainly composed of the above-mentioned organic polymer substance is used by coating or laminating the support 2 by a known method. The material of the support is not particularly limited, and in addition to plastic materials such as PET, polyvinyl chloride, and synthetic paper, which are currently used as card supports, paper can be used without any problem.

The thickness of the recording material is preferably 2 to 150 μm, and more preferably 5 to 50 μm.

In addition, in order to improve visibility, an aluminum vapor deposited layer or a colored layer may be provided between the recording material of the present invention and the support.
It is also possible to use auxiliary means, such as coloring the recording material by mixing a dye or the like.

Hereinafter, the present invention will be explained in detail with reference to Examples. In the following description, "parts" and "%" when referring to mixing ratios mean "parts by weight" and "% by weight," respectively.

Example 1 100 parts of Ryuron 800BL (polyvinyl chloride manufactured by Tosoh Corporation, Pm2O3) TVS
-N -2000G 3 parts (stabilizer manufactured by Nitto Kasei Co., Ltd.) Butyl stearate 1 part KE-3
1110 parts (hydrogenated rosin ester manufactured by Arayo Kagaku Co., Ltd.) The above composition mixture was kneaded at 190°C, and 40 parts
A 188 .mu.m film was obtained and dry laminated onto a 188 .mu.m PET film to obtain a sample for evaluating information recording performance.

In addition, a sheet with a thickness of 1 mm was produced in the same manner to obtain a sample for viscoelasticity measurement.

Example 2 Methyl methacrylate 75 parts Butyl acrylate 25 parts The above monomer composition mixture was 0.5% lauryl sulfate sorter.
was added to 200 parts of ion-exchanged water in which was dissolved. After stirring and dispersing thoroughly and raising the temperature to 70℃, ammonium persulfate 0.0
6 parts and reacted at 70°C for 5 hours to obtain a molecular weight of about 12
A polymer dispersion liquid of 0,000<Mw) was obtained. A coating solution was prepared by adding a film-forming agent and a leveling agent to this polymer dispersion.

This coating liquid has been subjected to corona treatment in advance to form a 188μ
The sample was coated on a PET film using a bar coater so as to have a film thickness of 10 μm after drying, and dried in an oven at 150° C. for 2 minutes to obtain a sample for evaluating information recording properties. In addition, the solvent was evaporated from the above coating solution to obtain a polymer solid content, and a thickness of 1 m was obtained.
A sample for viscoelasticity measurement was obtained by pressing at a temperature of 180°C.

Example 3 A sample for measurement was obtained in the same manner as in Example 2, except that 100 parts of methyl methacrylate was used as the monomer composition.

Comparative Example 1 Kneepilon E-2000 (polycarbonate manufactured by Mitsubishi Gas Chemical Co., Ltd.) was dissolved in tetrachloroethane to 20%
A coating solution was prepared.

This coating solution was applied to a 188 μm PET film using a bar coater so that the film thickness after drying was 10 μm.
Dry in an oven at 00°C for 2 minutes to obtain an evaluation sample for information recording performance. Further, the same polymer was pressed at 200°C to obtain a sample for viscoelasticity measurement with a thickness of 1 mm.

Comparative Example 2 Crisbon AH-810 (Dainippon Ink & Chemicals Co., Ltd.)
100 parts of toluene was mixed with 100 parts of polyurethane paint to prepare a coating solution, and a measurement sample was obtained in the same manner as in Example 2.

Comparative Example 3 Asaflex 81,040 parts (styrene-butadiene block copolymer manufactured by Asahi Kasei Industries, Ltd.) 60 parts of styrene-butyl acrylate copolymer (styrene/butyl acrylate-8/2) Sumilizer GM 1 part (Sumitomo Chemical Industries, Ltd.) Stabilizer manufactured by Co., Ltd.) The above composition was kneaded and extruded using an extruder at 200°C, and a cast film of 20 μm was obtained using a T-shaped die. In addition, a viscoelasticity measurement sample with a thickness of 1 mm was obtained in the same manner.

Comparative Example 4 Vinyryoku 37L 100 parts (polyvinyl chloride manufactured by Mitsubishi Monsando Kasei Co., Ltd., P=105
0) DOP 32 parts Pentaerythritol tetraacrylate 40 parts Ba-Zn stabilizer 3 parts Irgacure 651 2 parts (Photocrosslinking initiator manufactured by Ciba Geigy Co., Ltd.) The above composition was kneaded at 190°C and heated to 1100 AL using a calender roll. obtained a film of 188
After dry laminating on μm PET film, 16
UV irradiation was performed at 5 m/min using a 0 w/cm UV irradiation device to prepare samples for information recording performance evaluation and viscoelasticity measurement.

Comparative Example 5 In the formulation of Example 1, TK was used as polyvinyl chloride.
A measurement sample was obtained in the same manner except that -200OR (Shin-Etsu Chemical Co., Ltd. P-3800) was used.

Regarding the measurement sample obtained from the above method, the following
Dynamic viscoelasticity and information recording properties were evaluated.

(1) Dynamic viscoelastic evaluation Viscoelastic spectrometer YES manufactured by Wakagi Seisakusho Co., Ltd.
-F3 was used to measure from -50'C to 200'C at a frequency of 10 Hz by the tensile method and shear method, and the following values were read from the obtained chart.

(1a) Glass transition blended coal (Tg) Temperature (lb) showing the peak of tan δ corresponding to the main dispersion
Storage modulus E at a temperature 30°C higher than Tg - If the storage modulus is 1Xl0dyn/cn2 or higher, the value measured by the tensile method is 1xlO7dyn/cr1
In the case of less than 1'', the value obtained by multiplying the storage modulus (G-) by shear method by three times was determined as E-.

(lc) Minimum value of positive loss #, tan δ in the temperature range from Tg to a temperature 30° C. higher than Tg.

The results of dynamic viscoelasticity evaluation are shown in Table 1.

(2) Information recording performance (2a) Using a frost mold with a size of 10 mm x 20 mm that has a solenoid pressure mechanism that imparts strain, the set temperature of the mold is set at 5°C intervals from the Tg of the measurement sample above to 200°C. The temperature was raised stepwise to
Each gave a distortion.

The ability to impart distortion is determined by visually observing the sharpness of the frosted part, and the temperature range in which clear distortion can be imparted is at least 1.
If the temperature is 0°C or higher, mark it as “○”; if it does not, mark it as “×”
”.

(2b) Fusion bonding property (2a) After repeatedly applying strain 10 times under temperature conditions that clearly apply strain, the surfaces of the recording material and mold were observed to check for adhesion resistance. Na. Regarding the evaluation of fusion properties, those in which the temperature range in which no adhesion resistance is observed are at least 10'C or higher are marked as "○J", and those in which no adhesion resistance is observed are marked as "x".

(2c) Strain recovery property A sample was clearly strained in (2a), and frost-like strain was applied under the straining conditions (2a) under the temperature conditions in which no fusion occurred in (2b). Characters were printed by partially recovering the distortion using a printer with a thermal head, and their visibility was visually evaluated. The printing conditions were a head pressure of 500 g/rrf, a current application time of 3 ms/dot, and a voltage of 11 ■.

(2d) Preservability (2C) Samples with printed characters were stored at 40°C and 50% RH.
The visibility of the characters after being left for 7 days was visually judged, and those that were clear were rated "○" and those that were unclear were rated "x".

Table 2 shows the evaluation results for information storage performance.

Table 1 Table 2 (Effects of the Invention) The information recording material of the present invention has the advantage that recording and erasing can be repeated with low energy and in a short time. This advantage also has no adverse effect on other functions of the cards, and can be applied to various types of cards.

[Brief explanation of the drawing]

40 Description of the Drawings FIG. 1 is a diagram showing an example of the temperature dependence of the viscoelastic properties of an organic polymer substance, and FIG. 2 is a sectional view showing the principle of recording with the recording material of the present invention. 1...Information recording material 2...Support patent applicant Mitsubishi Plastics Co., Ltd. agent Patent attorney Kumi Kondo 2---No 7. : Figure 1 'iL K

Claims (1)

[Claims] An information recording material provided on the surface of a support and composed mainly of an organic polymer substance, the recording material having a glass transition temperature in the range of 50 to 140°C and 30°C higher than the glass transition temperature. The storage modulus is 6×10
An information record characterized by having a loss tangent in the range of ^6 to 1 x 10^8 dyn/cm^2 and a loss tangent of 0.15 or more in the temperature range from the glass transition temperature to a temperature 30°C higher than the glass transition temperature. material.