JP2015189033A - Card made of plant-based plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a card made of a plant-based plastic whose difficulty in production is eliminated and which has durability to heat and humidity.SOLUTION: The card is produced by using a noncrystalline aromatic polyester sheet as a central layer, using the three-layer structural core sheets 10 on both surfaces of the sheet, laminating the transparent oversheets 21, 22 comprising a noncrystalline polyester resin on both outer surfaces of the core sheets 10 and heat-fusion-bonding between each sheet. The three-layer structural core sheet 10 is comprised of an intermediate layer 11, a surface layer 12 and a rear face layer 13, and each layer is composed of a lactic acid-based polymer, a noncrystalline aromatic polyester resin, a thermoplastic elastomer and an inorganic filler. Besides, the percentage of the noncrystalline aromatic polyester resin in the resin composition composing the surface and rear face layers is set to be higher than that of the aromatic polyester resin in the resin composition composing the intermediate layer. The lactic acid-based polymer is a plant-derived polymer.

Description

The present invention relates to a card using vegetable plastic. Specifically, the present invention relates to a card using polylactic acid (lactic acid-based polymer) made from onion starch as a raw material, that is, a card such as an IC card or a magnetic card. In a card using plant-derived polylactic acid as a core sheet, by changing the core sheet layer structure to a multilayer structure instead of the conventional single layer core sheet, manufacturing problems and characteristics of the card itself can be improved. Regarding improved cards.

In recent years, various plastic cards have been considered environmentally friendly. Conventional card made of vinyl chloride may be incinerated due to the generation of hydrogen chloride or dioxins as biologically disturbing substances. On the other hand, various prepaid cards mainly composed of polyethylene terephthalate (PET) have high durability characteristics, but some of them are recovered after use, but most of them are discarded as they are, so they are permanently There is a problem that it remains as garbage and damages the environment.
In addition, since vinyl chloride and PET are raw materials derived from petroleum, there is a problem that if they are used continuously, resources will be depleted.
Therefore, research has been conducted on the use of biodegradable materials derived from plants that readily deteriorate and disappear after use, and various test products and practical products have also been realized. Plant-derived materials are regenerated with carbon dioxide, water and sunlight, so there is no concern about resource depletion.

There are various types of biodegradable materials, but in recent years, the use of plant plastics, especially polylactic acid made from onion starch as a raw material, has been frequently used.
IC cards and magnetic cards using polylactic acid (PLA; lactic acid-based polymer) made from this onion as a card substrate have already been manufactured and put into practical use. However, this conventional card base material uses a single layer sheet made of polylactic acid as a core sheet, and has various problems as follows.

That is, (1) when a picture is silkscreen printed on a single-layer core sheet, the surface of the sheet is crystallized by the solvent of the ink, and the adhesiveness of the ink and the adhesiveness with the oversheet laminated thereon are lowered. This is because even if the front side of the core sheet is printed only with register marks, it is affected by back side printing during stacking and storage.
In addition, after printing, when aging is performed by heating to 40 ° C. or higher, crystallization is promoted. Therefore, aging at a relatively low temperature that does not reach 40 ° C. is required.
(2) In addition, the single-layer sheet made of polylactic acid can be heat-sealed only between the polylactic acid sheets, and cannot be heat-sealed with other sheets without using an adhesive sheet.
(3) Furthermore, the card with a single-layer sheet has a problem that the strength is deteriorated in a short time because it is weak to the moisture and heat resistance test.

Accordingly, the present invention is intended to solve the above-mentioned problems while satisfying the usage standards of plant-derived materials. In general, in order to admit that it is a plant-derived material, it is necessary that the plant-derived material occupies 25.0% by weight or more of the entire material (biomass plastic identification display system <bio Plastic Association>).
In the present invention, instead of the conventional single-layer core sheet made of polylactic acid, a layer containing a large amount of a lactic acid polymer is used as an intermediate layer, and an amorphous aromatic polyester resin is mainly used on the front and back surfaces thereof. The present invention intends to solve the above problem by using a three-layer core sheet in which layers are laminated.

Patent Documents 1 and 2 are prior patent documents related to an IC card using a biodegradable substrate. However, each uses a single layer sheet, and it does not describe using the core sheet material laminated | stacked like this application. Moreover, there exists patent document 3, 4 regarding the sheet | seat for cards using the lactic acid-type polymer derived from a plant.

Japanese Patent Laid-Open No. 2000-141956 JP 2010-188637 A JP 2009-235172 A JP 2012-247828 A

It is an object to solve the difficulty in card production when using vegetable plastics and to improve the durability of the wet heat test of the card itself.
Therefore, the card core sheet is a three-layer co-layer in which a layer mainly composed of a plant-derived lactic acid polymer is used as an intermediate layer, and a layer mainly composed of an amorphous aromatic polyester resin is laminated on the front and back surfaces. Use an extruded sheet.

The gist of the present invention is that a non-crystalline aromatic polyester resin sheet is used for the center layer of the card base, a three-layer core sheet is used on both sides thereof, and further, both outer surfaces of the three-layer core sheet are used. In a card in which a transparent oversheet made of an amorphous aromatic polyester resin is laminated and the sheets are heat-sealed, the three-layer core sheet is composed of three layers of an intermediate layer, a surface layer, and a back layer. The intermediate layer, the surface layer, and the back layer are composed of a lactic acid polymer, a non-crystalline aromatic polyester resin, a thermoplastic elastomer, and an inorganic filler, and constitute the surface layer and the back layer. The ratio of the non-crystalline aromatic polyester resin in the resin composition is larger than the ratio of the aromatic polyester resin in the resin composition constituting the intermediate layer, and the lactic acid polymer is Cards, there was used vegetable plastic, which is a lactic acid series polymer derived.

In the above, the ratio of the thickness of the intermediate layer to the thickness of the front surface layer or the back surface layer can be in the range of 12: 1 to 8: 1, and the card is attached to the contact terminal plate and the contact terminal plate. An IC card having an integrated circuit mounted thereon or a magnetic card having a magnetic stripe can also be used.

(1) The problem that the single-layer core sheet mainly composed of a lactic acid-based polymer derived from a plant is crystallized by a solvent or heating of the printing ink and the heat-fusibility is lowered is solved. Thereby, it becomes possible to apply heat to the aging after printing of the core sheet, and the aging time is shortened.
(2) The layer mainly composed of an amorphous aromatic polyester resin that is the front and back of the core sheet,
Since the heat-sealability between each other is not limited, as in the past, heat-seal incompatibility between the core sheet mainly composed of a lactic acid polymer and the oversheet mainly composed of an amorphous aromatic polyester resin The problem is solved.
(3) The finished card itself has improved durability against the heat and humidity resistance test.

It is a top view of the card | curd of this invention. It is a figure explaining the layer structure of the card | curd of this invention. It is a figure which shows the partial cross section of a contact-type IC card. It is sectional drawing which shows the base material for core sheets of 3 layer structure used by this invention. It is a figure which shows the test result of an environmental resistance test. It is a figure explaining the layer structure of a comparative example card | curd.

Since this invention has the characteristics in the base material for core sheets used for the core material of a card | curd, suppose that the said base material for core sheets is demonstrated first.
FIG. 4 is a cross-sectional view showing a three-layer core sheet substrate used in the present invention.
The core sheet substrate 10 has a three-layer structure including an intermediate layer 11, a surface layer 12, and a back layer 13. The intermediate layer 11 and the front and back layers 12 and 13 are made of a lactic acid polymer, a non-crystalline aromatic polyester resin, a thermoplastic elastomer, and an inorganic filler.
However, the ratio of the non-crystalline aromatic polyester resin in the resin composition constituting the surface layer 12 and the back layer 13 is the ratio of the non-crystalline aromatic polyester resin in the resin composition constituting the intermediate layer 11. Has been more than. Here, the lactic acid polymer refers to a lactic acid polymer derived from a plant, particularly a lactic acid polymer obtained by fermenting onion starch.

The intermediate layer 11 is a mixture containing 30 to 75 parts by mass of a lactic acid polymer, 23 to 50 parts by mass of an amorphous aromatic polyester resin, and 10 to 32 parts by mass of a thermoplastic elastomer (each part by mass is composed of 3 components). The surface layer 12 and the back layer 13 are composed of 0-25 parts by mass of a lactic acid polymer, 50-80 parts by mass of an amorphous aromatic polyester resin, and a thermoplastic elastomer 10. A resin composition comprising a mixture containing -32 parts by mass (each part by mass is a proportion by mass relative to 100 parts by mass of the three components).
The resin composition constituting the front surface layer 12 and the back surface layer 13 is more than the proportion of the amorphous aromatic polyester-based resin in the resin composition constituting the intermediate layer in the proportion of the amorphous aromatic polyester-based resin, There is a feature that constitutes the main component. The main component means a resin composition in which the non-crystalline aromatic polyester-based resin has the largest proportion in the composition resin component. As described above, an inorganic filler is included as a coloring material in addition to the resin component.

The blending ratio of the lactic acid-based polymer is preferably higher when the ratio of the plant-derived component occupied by the card is increased, but if the blending ratio is too high, the impact resistance tends to decrease, Moreover, it becomes the tendency for a melt | fusion property with the oversheet which has an aromatic polyester-type resin as a main component to fall. In such a case, the mixing ratio of the lactic acid polymer may be 45 to 50 parts by mass.
The purpose of blending the non-crystalline aromatic polyester resin is to obtain rigidity when used as a card and to complement the fusion with the oversheet mainly composed of aromatic polyester resin when making a card. This is the purpose. The purpose of blending the thermoplastic elastomer is to improve the impact resistance of the lactic acid polymer and to increase the compatibility between the lactic acid polymer and the amorphous aromatic polyester resin. It is preferable to adjust the blending amount so as to meet the purpose.

The non-crystalline aromatic polyester-based resin is generally a dehydrated condensate of an aromatic dicarboxylic acid and a diol, and is particularly low in crystallinity. As an amorphous aromatic polyester resin, a product (trade name “PET-G”) in which 30 mol% of an ethylene glycol component in polyethylene terephthalate is replaced with 1,4 cyclohexanedimethanol is commercially available from Eastman Chemical. However, the present invention is not limited to this.

The thermoplastic elastomer is a rubber-like material composed of a polyester elastomer and a styrene elastomer. The inorganic filler contains a titanium oxide (TiO ₂ ) pigment or the like. The card core material needs to be white to make it easy to visually recognize the surface pattern, and a rutile-type white titanium oxide pigment is preferably used.
In the above, the surface layer 12 and the back surface layer 13 may have the same thickness, and the ratio of the thickness of the intermediate layer 11 to the thickness of the surface layer or the back surface layer is preferably in the range of 8: 1 to 12: 1. . Thickening the intermediate layer 11 is for the purpose of increasing the amount of plant-derived material used.
Since this three-layer core sheet base material (hereinafter also referred to as “three-layer core sheet”) 10 is obtained by a co-extrusion method, delamination does not inherently occur.

Next, the card of the present invention will be described with reference to FIGS.
FIG. 1 is a plan view of the card of the present invention. In FIG. 1, an IC card having a contact IC chip is illustrated, but the present invention is not limited to an IC card, and may be a magnetic card or a card using both an IC chip and a magnetic stripe.
The card 1 of the present invention is a flat card having a predetermined plane size (usually 53.98 mm × 85.60 mm) of ID-1 type defined by ISO (JISX6301).
When the card 1 is an IC card, as shown in FIG. 1, it has a contact terminal plate 2 on the surface, and an IC chip (semiconductor integrated circuit) (not shown) is mounted on the lower surface of the contact terminal plate 2. As described above, the magnetic card having only the magnetic stripe 4 without the IC chip may be used. The magnetic stripe 4 on the front side is concealed so as not to be normally visible.
On the surface of the card 1, embossed characters for displaying a card number 31, an expiration date 32, and a user name 33 are displayed by stamping. Furthermore, it has a logo mark 34 and a transferred hologram pattern 35, and also has a sign panel, a magnetic stripe, etc. on the back surface (not shown).
These configurations are usually the same as ordinary cards and do not exhibit special features.

Since the card of the present invention is characterized by its base material structure, it will be described below.
FIG. 2 is a diagram for explaining the layer structure of the card of the present invention.
In the card 1 of the present invention, a non-crystalline aromatic polyester resin (PET-G) sheet is used for the inner sheet 5 that is a central layer, and the three-layer core sheet 10 is laminated on both sides thereof.
Transparent oversheets 21 and 22 made of an amorphous aromatic polyester resin are laminated on the front and back outer surfaces of the three-layer core sheet 10. The non-crystalline aromatic polyester-based resin is excellent in transparency, withstands embossed letters, has good transferability on hologram foils and sign panels, and has excellent suitability as an oversheet.
As described above, since the three-layer core sheet 10 is used, the front and back layers 12 and 13 are non-crystalline aromatic polyester-based resins. Good heat fusion at a low temperature can be ensured.
The inner sheet 5 is also inserted in order to ensure low-temperature heat fusion property with the three-layer core sheet 10. Note that the non-contact type IC card has a layer structure different from that of the card 1 because an antenna sheet is inserted.

The conventional method using a single-layered lactic acid-based polymer as a core material has a problem in that it cannot be thermally fused to the oversheets 21 and 22 or the inner sheet 5 which are non-crystalline aromatic polyester resins. . Therefore, it was necessary to print on the core sheet using a vinyl-based silk screen medium ink to improve the adhesion, but by using the three-layer core sheet 10, such a printing process is unnecessary. became. Further, there is a problem that the surface of the lactic acid polymer is crystallized by the solvent of the printing ink, and the crystallized surface cannot be fused even at a high temperature.

In the above card, when a magnetic concealment layer or a pattern is provided on the card surface, the transfer film 6 is used for painting. The transfer film 6 is a film in which an image for painting (including a magnetic concealment layer) 63 and an adhesive layer 64 are provided on a transfer substrate 61 such as PET via a peeling protective layer 62. After the transfer, the transfer substrate 61 is peeled off.
In FIG. 2, the magnetic stripe 4 is provided on the front surface of the card 1, but it may be the back surface of the card 1 or both front and back surfaces. When the magnetic stripe 4 is provided on the card surface, the magnetic layer is transferred to the oversheets 21 and 22 in advance, and then the painting is performed with the transfer film 6.

FIG. 3 is a diagram showing a partial cross section of the contact IC card. The cross section of the IC module part in case the card | curd 1 is a contact-type IC card is shown.
When the IC module 8 is mounted on the card 1, the IC module embedding recess 7 is excavated in the card substrate, and the IC module 8 with the contact terminal plate 2 is embedded in the embedding recess 7. Since the thickness of the contact terminal plate 2 is normally about 0.1 mm, the oversheet 21 set to the thickness is cut into a hole of a size that allows the contact terminal plate 2 to be fitted, and the center portion of the hole is further removed. The IC module 8 is fitted by cutting.
Since the thickness (the height of the mold part) of the IC module 8 exceeds 0.5 mm, the depth of the recessed part 7 for embedding the IC module exceeds the inner sheet 5 and reaches the three-layer core sheet 10 on the lower surface side. Become deep. However, in order to prevent the IC module 8 from being seen through from the back side, the depth does not reach the transparent oversheet 22.
A portion other than the mold resin portion on the back surface of the contact terminal plate 2 of the IC module 8 is fixed to an intermediate step portion in the concave portion 7 for embedding the IC module by an adhesive 9.

Next, a card manufacturing method will be described.
First, printing is performed on the three-layer core sheet 10. On the front-side core sheet 10a, offset printing of a position display mark (referred to as “dragonfly” at the manufacturing site), which is a marker for punching, is mainly performed. In many cases, the back side core sheet 10b is printed on the entire surface in silver by silk screen printing, and then black characters and designs such as explanatory text are offset printed with ultraviolet curable ink.
In the case of a conventional single-layer lactic acid-based polymer base material, it has been necessary to print a medium ink using a silk screen in order to improve the adhesion after printing on the core sheet. Then, there is an advantage that the process becomes unnecessary.

After silk screen printing, heat and age (age). In the case of the conventional single-layer base material, distortion and curl are generated due to the contraction of the base material due to heat. Aging within the time became possible. Aging is intended to completely dry the ink, but it may be inevitably stored since the printed core material cannot be used immediately in the process.
The core sheet can be stored for about two months without interleaf (paper inserted between cores). “Stand-by-bar storage” means that the core sheets after printing are directly stacked and stored without using interleaving paper, so that there is no problem in manufacturing thereafter.

Next, hot pressing is performed. The inner sheet 5 is a central layer, printed three-layer core sheets 10a and 10b are placed on both sides thereof, and transparent oversheets 21 and 22 are temporarily stacked on both sides of the three-layer core sheets 10a and 10b. Then, the pattern transfer film 6 is placed on the front surface side, and finally, hot pressing is performed between the press plates. When the magnetic stripe 4 is provided, the magnetic stripe is transferred to either or both of the oversheets 21 and 22 in advance.
In the case of the conventional single-layer lactic acid polymer core sheet, there is a problem that the oversheet does not melt if crystallization occurs, but such a problem does not occur in the three-layer core sheet.
Hot pressing is possible in the range of 115 ° C to 135 ° C.
The transfer substrate 61 of the transfer film 6 is peeled off after the transfer is completed.

The steps so far are performed in a multi-faceted state. After inspecting in a large format with multiple faces, a process of punching to individual card sizes is performed. In the case of an IC card, the modularized IC chip 3 is thereafter mounted as described above.
After punching, the output of the magnetic stripe and IC chip is inspected, the hologram foil and sign panel are transferred and inspected by character embossing, and the card is completed.
Hereinafter, it demonstrates more concretely based on an Example.

(Example)
The embodiment will be described with reference to FIG.
EC-823 (thickness: 275 μm) manufactured by Mitsubishi Plastics, Inc. was used as the three-layer core sheet 10a, 10b. This three-layer core sheet has a thickness ratio of intermediate layer: front / back surface layer = 12: 1. That is, the front layer and the back layer have a thickness of 1, whereas the intermediate layer is a three-layer coextruded material having a thickness 12 times that of the intermediate layer.
The ratio of plant-derived lactic acid polymer: non-crystalline aromatic polyester resin: thermoplastic elastomer: inorganic filler in the intermediate layer 11 of the three-layer core sheet 10a, 10b is 45: 30: 10: 15. belongs to. The ratio of the non-crystalline aromatic polyester resin: thermoplastic elastomer: inorganic filler in the front surface layer 12 and the back surface layer 13 is 75:10:15. Since a white core sheet, includes titanium oxide as the inorganic filler (TiO ₂₎ is. In addition, each ratio is a mass ratio with respect to 100 mass parts of 3 components total.

As the inner sheet 5, AS-WHI-TK (thickness: 70 μm) manufactured by Mitsubishi Plastics, Inc. was used. This sheet is made of a non-crystalline aromatic polyester resin (PET-G).
Further, PG-MCT (thickness: 100 μm) manufactured by Mitsubishi Plastics Co., Ltd. was used for the oversheets 21 and 22. This sheet is made of a transparent non-crystalline aromatic polyester resin. In addition, the magnetic stripe 4 was previously transferred to the oversheet 22 for the back surface.

Using a UV-curing offset ink, a registration mark for cutting marks is printed on the front-side core sheet 10a of the three-layer core sheet, and the back-side core sheet 10b is silk-screen printed except for the magnetic stripe portion. Silver solid printing was performed. Thereafter, black patterns and characters were printed on the silver solid printing surface using an ultraviolet curable offset printing ink.
After printing, aging was performed at 40 ° C. for 12 hours in an aging room.

The inner sheet 5 is used as an intermediate layer, and the printed three-layer core sheets 10a and 10b are placed on both sides of the inner sheet 5 with the printed layer as an outer surface, and the transparent sheets are formed on both sides of the three-layer core sheets 10a and 10b. The oversheets 21 and 22 were placed and temporarily stacked, and the pattern transfer film 6 was further placed on the surface side, and hot pressing was performed between the press plates. The hot press conditions are 125 ° C., 45 k / N, and 270 seconds.
After the transfer substrate 61 of the transfer film 6 was peeled and removed, it was inspected and punched into individual card sizes. The overall thickness of the card after punching was in the range of 760 ± 80 μm.

The upper portion of the IC module embedding concave portion 7 having a size capable of fitting a thickness of 0.1 mm of the contact terminal plate 2 is cut into the card base material, and the central portion of the hole is further excavated, and the IC module 8 The depth is such that the mold part can be embedded. An IC module 8 with a contact terminal plate 2 having a height of the mold part from the terminal plate surface of 0.5 mm was embedded in the concave portion 7 for embedding the IC module. The output of the magnetic stripe 4 and the IC chip 3 was inspected, the hologram foil and the sign panel were transferred, and the characters were embossed and inspected to complete the IC card with the magnetic stripe.

(Comparative example)
FIG. 6 is a diagram illustrating the layer structure of the comparative example card. A comparative example will be described with reference to FIG.
CCX-004 (thickness: 295 μm) manufactured by Mitsubishi Plastics, Inc. was used as the core sheets 15a and 15b. The core sheet is mainly composed of a plant-derived lactic acid polymer. Since it is a white core sheet, titanium oxide (TiO ₂ ) is included as an inorganic filler.

For the inner sheet 5, CCX-005 (thickness: 40 μm) manufactured by Mitsubishi Plastics, Inc. was used. This sheet is made of polylactic acid (PLA).
Further, PG-MCT (thickness: 100 μm) manufactured by Mitsubishi Plastics Co., Ltd. was used for the oversheets 21 and 22. This sheet is the same as that of the example and is made of a transparent non-crystalline aromatic polyester resin. In addition, the magnetic stripe 4 was previously transferred to the oversheet 22 for the back surface.

On the surface-side core sheet 15a, an ultraviolet curable offset ink is used to print a register mark for cutting, and an adhesive vinyl chloride-based silk screen printing medium ink ("VAHS medium" manufactured by Showa Ink Co., Ltd.) ) Was printed on the entire surface. The purpose is to increase the adhesion to the oversheet. The back side core sheet 15b was subjected to silver solid printing by silk screen printing except for the magnetic stripe portion. Thereafter, black patterns and characters were printed on the silver solid printing surface by ultraviolet curable offset printing. Further, similarly to the surface side, an adhesive vinyl acetate-based silk screen printing medium ink (“VAHS medium” manufactured by Showa Ink Co., Ltd.) was printed on the entire surface. After printing, aging was performed for 12 hours at room temperature in an aging room.

Using the inner sheet 5 as a central layer, the printed core sheets 15a and 15b are placed on both sides thereof, and the transparent oversheets 21 and 22 are placed on both sides of the core sheets 15a and 15b, and temporarily stacked. Further, a pattern transfer film 6 was placed on the front surface side, and was hot-pressed by being sandwiched between press plates. The hot press conditions were 125 ° C., 45 k / N, and 270 seconds.
After the transfer substrate 61 of the transfer film 6 was peeled and removed, it was inspected and punched into individual card sizes. The overall thickness of the card after punching was in the range of 760 ± 80 μm.

The cards of the examples and comparative examples were all provided with practical performance.
In the cards of the example and the comparative example, there is a difference in durability (environmental resistance test) after card formation and storage stability of the intermediate material after printing.

(Environmental resistance test)
About the contact type IC card obtained by an Example and a comparative example, it is 7 days (168 hours), 14 days in the test article of untested state (0 hours), and a 60 degreeC, 90% RH thermostat. (336 hours), 21 days (504 hours), 30 days (720 hours), 35 days (840 hours), 42 days (1008 hours), each test article was taken out of the thermo-hygrostat and the temperature was 23 ° After being placed under the room temperature condition of C, a hydroshot test was performed to calculate the energy required for destruction.

The hydroshot test was conducted using a hydroshot impact tester “HTM-1” manufactured by Shimadzu Corporation. In the test, a 0.5 inch diameter weight was made to collide with the IC card surface at a speed of 3 m / sec, and the energy required to cause damage in half of the number of tests (50%) was calculated.
Usually, an energy of 200 kgf · mm is regarded as a reference for substrate deterioration.
The damage refers to delamination of the card substrate (delamination occurs between the layers of the substrate at the end of the card). The measurement is based on JISK7124.
The results are as shown in Table 1, which is shown in FIG.

表１、および図５が示すように、３層構成コアシート１０を使用した実施例は、１００８時間(４０日)を超えても２００ｋｇｆ・ｍｍの基準衝撃値に耐えるのに対し、従来の単層コアシートを使用した比較例の場合は、７２０時間（３０日）を超えた時点で、２００ｋｇｆ・ｍｍの衝撃を与えると層間剥離が発生し、その後は急速に劣化することが認められた。これにより、新コアシート用基材（３層構成コアシート）の耐久性が優れることが認められる。

As shown in Table 1 and FIG. 5, the example using the three-layer core sheet 10 can withstand a standard impact value of 200 kgf · mm over 1008 hours (40 days), whereas the conventional single sheet is used. In the case of the comparative example using the layer core sheet, it was recognized that delamination occurred when an impact of 200 kgf · mm was applied after 720 hours (30 days), and then rapidly deteriorated. Thereby, it is recognized that the durability of the new core sheet base material (three-layer core sheet) is excellent.

(Preservation test of intermediate material)
In this test, the intermediate material refers to a material after silk screen printing and offset printing are performed on the back side core sheet. The back of the IC card or magnetic card is usually printed with silver and black fine characters.
It is preferable that the intermediate material can be stored for a certain period in a state in which the base materials are stacked directly (referred to as bar stacking) without inserting slip sheets because of the necessity of drying completely and manufacturing convenience. . However, in the conventional core sheet, when silk screen printing is performed on a single layer sheet, the surface of the sheet is crystallized by the solvent of the ink, and there is a problem in that the adhesiveness with the oversheet to be laminated is lowered. Further, after printing, heating and aging (aging) further promotes crystallization, so that room temperature drying is required.
The printing conditions are the same as those in each example and the comparative example. That is, in the comparative example, the adhesive silk screen medium ink is printed, but not in the example.

Therefore, in this test, when 1000 printed core sheets were stacked in a bar and stored at room temperature for 1 month, 2 months, and 3 months without inserting slip sheets, they were placed on the bottom 10 sheets. It was tested how much peel (peeling) strength was obtained when the printed surface of the core sheet and the oversheet were hot-pressed at 125 ° C. (number of tests = 5). In this case, the pressure in the lowermost layer is about 5.35 kgf / cm ² . The results are shown in Table 2.

From the above results, the peel strength between the core sheet of the comparative example and the oversheet does not satisfy the condition of the reference value (0.35 kg / cm) even when stored for 1 month, and the core sheet of the example is aged for 3 months. It was confirmed that sufficient peel strength was obtained between the three-layer core sheet and the oversheet. In the determination of Table 2, the mark “◯” indicates that the reference value is satisfied, and the mark “X” indicates that the reference value is not satisfied.
The same test was performed between the core sheet and the inner sheet, and similar results were obtained.

DESCRIPTION OF SYMBOLS 1 Card 2 Contact terminal board 3 IC chip 4 Magnetic stripe 5 Inner sheet 6 Transfer film 7 IC module embedding recessed part 8 IC module 9 Adhesive 10 Core sheet base material Three-layer core sheet 10a Front side core sheet 10b Back side Core sheet 11 Intermediate layer 12 Surface layer 13 Back layer 21, 22 Oversheet 31 Card number 32 Expiration date 33 User name 34 Logo mark 35 Hologram pattern

Claims (4)

A non-crystalline aromatic polyester resin sheet is used for the center layer of the card base, a three-layer core sheet is used on both sides thereof, and an amorphous aromatic polyester is used on both outer surfaces of the three-layer core sheet. In a card in which a transparent oversheet made of a resin is laminated and each sheet is heat-sealed, the three-layer core sheet is composed of three layers of an intermediate layer, a surface layer, and a back layer, and the intermediate layer and the surface The layer and the back layer are composed of a lactic acid-based polymer, a non-crystalline aromatic polyester-based resin, a thermoplastic elastomer, and an inorganic filler. In the resin composition constituting the surface layer and the back layer, The proportion of the non-crystalline aromatic polyester resin is greater than the proportion of the aromatic polyester resin in the resin composition constituting the intermediate layer, and the lactic acid polymer is a lactic acid polymer derived from a plant. Card Using plant plastic, which is a body. 2. The card using vegetable plastic according to claim 1, wherein the ratio of the thickness of the intermediate layer to the thickness of the front surface layer or the back surface layer is in the range of 12: 1 to 8: 1. The card using vegetable plastic according to claim 1 or 2, wherein the card is an IC card having a contact terminal plate and an integrated circuit mounted on the contact terminal plate. The card using vegetable plastic according to claim 1 or 2, wherein the card is a magnetic card having a magnetic stripe.

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