JPH08267968A - Biodegradable card - Google Patents

Abstract

(57) [Abstract] [Objective] The present invention is a biodegradable card used for credit cards, cash cards, ID cards, IC cards, identification cards, employee ID cards, membership cards, medical certificates, etc. The purpose of the present invention is to provide a biodegradable card composed of multi-layer biodegradable plastic sheets, which gives a high-grade, beautiful card that can be biodegraded in landfill or compost after the card has been used. . [Structure] A biodegradable plastic card composed of multiple layers has a plastic sheet having biodegradability as a center core, and a thermoplastic polymer containing polylactic acid or a copolymer of lactic acid and oxycarboxylic acid as a main component on both sides thereof. It is a biodegradable card characterized by laminating an oversheet composed of.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable card used for credit cards, cash cards, ID cards, IC cards, identification cards, employee ID cards, membership cards, medical certificates, etc. The present invention relates to a biodegradable card which is made of a biodegradable plastic sheet and has a high-grade feeling and is a beautiful card, and which can be biodegraded after being used in a landfill or in compost after being used.

[0002]

2. Description of the Related Art Conventionally, various cards are used to prove their identity.
It is used in a wide range of fields such as D cards, membership cards, cash cards with financial value, and credit cards. These cards are usually sold or rented to the user, then the user uses the card, and is disposed of when the card is used up. For example, most credit cards, cash cards, ID cards and the like currently in circulation are made of vinyl chloride having a thickness of 700 to 800 μm. Cards made of these vinyl chloride materials are printed with an appropriate pattern on both sides of a white center core of about 500 μm, and a transparent vinyl chloride sheet of about 100 μm is pasted on both sides of this center core by a hot pressing method. Form the material. Further, pattern / character information and the like are printed on these card base materials, and variable information is recorded in a magnetic recording section or an optical recording section provided on the card base material.

This card is a security measure because it is difficult to falsify or forge by attaching a transparent sheet to the picture / character information printed on the center core. Further, these conventional plastic cards made of vinyl chloride or the like are currently incinerated or disposed of as waste by landfill or the like when used.

On the other hand, conventionally, a card using paper as a card base has been used, and in particular, the paper is easy to dispose of such as incineration and landfill, and the manufacturing cost is low. It is considered to be the best card material for solving environmental problems such as dust. However, when paper is used as a card substrate, durability, bending resistance,
Considering the suitability as a card such as water resistance, chemical resistance, waterproofness, surface smoothness, glossiness, etc., it is inferior in all respects to the function, so use paper alone as a pass ticket, admission ticket, ticket It has been considered unsuitable for cards that are used for a certain period of time and are limited to temporary use. In this case, it is conceivable that a synthetic resin such as polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, or an outer layer other than plastic such as aluminum foil is laminated as a protective layer on the paper base material, but these are not disposable. It is problematic and has the drawback of not being so different from conventional plastic cards.

Further, JP-A-57-150393, JP-A-59-220192 and JP-A-51-9.
As disclosed in Japanese Patent No. 3991 and Japanese Patent Application Laid-Open No. 63-260912, a plastic that can be decomposed in a natural environment such as light or underground has been developed, and it has come to be used especially for disposable products. It has been commercialized. In the field of this card, JP-A-5-42786 and JP-A-5-8
In Japanese Patent No. 5088, it is proposed to use a decomposable plastic for the card base material.

[0006]

As described above, conventional cards are widely used because they are made of vinyl chloride, ABS resin, etc., have excellent physical properties, and are inexpensive. However, these cards are currently disposed of by incineration or landfill as waste for disposal after use.However, in the case of incineration, the combustion temperature rises due to incineration, which increases the durability of the incinerator. There is a problem of pollution and the problem of pollution such as combustion gas, and in the landfill treatment, since it exists in its original form without being decomposed,
It remains semi-permanently as trash on the earth, and its impact on the natural environment has become a problem.

The oversheet covering the center core of the card is required to have transparency, and is one of the measures for preventing forgery / falsification of the pattern printed on the center core or an appropriate pattern. Further, when the transparency of the oversheet decreases, the printed pattern becomes unclear, and when the transparency is high, the pattern printed on the center core can be seen clearly and the security effect of the printed pattern is improved. However, the maximum light transmittance of a commercially available transparent vinyl chloride sheet of about 100 μm is 88%, and the transparency is not sufficient.
Moreover, it is not degradable.

Further, the biodegradable card proposed in recent years is composed of almost a single biodegradable plastic or is a paper substrate coated on both sides. These cards had limited physical properties inherent to the material, and were insufficient in rigidity, strength, resistance, etc., so there were still few cases where they were applied. Cards with a biodegradable resin coating on both sides of the paper substrate have improved durability compared to paper cards, but with respect to durability, bending resistance, water resistance, chemical resistance, waterproofness, mechanical properties, etc. However, the range of use was limited due to the limitation of the paper base material.

This simple biodegradable plastic material is
Many of them are similar to polyethylene and have softness, but they are inferior in mechanical strength suitable for gate characteristics such as rigidity during mechanical reading / writing. In addition, examples of biodegradable resins that have approached the mechanical strength required by the card include polymer sheets containing polylactic acid or a copolymer of lactic acid and oxycarboxylic acid as a main component.
However, these biodegradable plastics are still expensive, and it is considered that there are significant cost problems in producing a card by itself. Further, the polylactic acid-based polymer resin has an extremely slow decomposition rate in the initial hydrolysis process, and it is necessary to accelerate the decomposition under heating conditions such as in compost equipment. It is considered that the decomposition rate of the polylactic acid-based single card becomes slower.

[0010]

DISCLOSURE OF THE INVENTION As a result of intensive studies on the above problems, the present inventors have found that, according to the invention of claim 1, a biodegradable plastic card composed of multiple layers is at least biodegradable. A plastic sheet having properties is used as a center core, and an oversheet made of a thermoplastic polymer having polylactic acid or a copolymer of lactic acid and oxycarboxylic acid as a main component is laminated on both sides of the center core.

According to the second aspect of the present invention, the resin of each layer in the biodegradable card contains a filler and an additive.

According to the third aspect of the invention, the resin of each layer in the biodegradable card is biaxially stretched.

The oversheet that covers both sides of the center core of the biodegradable card of the present invention is a transparent sheet, and mainly comprises polylactic acid or a copolymer of lactic acid and oxycarboxylic acid, which has a high light transmittance and excellent physical properties. Since the degradable plastic sheet obtained by biaxially stretching the thermoplastic polymer as a component is used, the pattern printed on the center core can be seen more clearly than the conventional transparent sheet made of vinyl chloride sheet.

As the center core material of the biodegradable card of the present invention, a biodegradable plastic material which is cheaper than the oversheet material can be used, and the card cost can be reduced. The material of the center core is not particularly limited, and biodegradable plastics such as chemically synthesized aliphatic polyester, natural polymer, and microorganism-produced polyester produced by fermentation method are used.

Further, various fillers can be added to the resin of each layer in the biodegradable card of the present invention, and in particular, the resin of the center core can be modified by adding an appropriate amount of filler. It is effective in reducing costs.

[0016]

The biodegradable card of the present invention comprises a thermoplastic polymer containing polylactic acid or a copolymer of lactic acid and oxycarboxylic acid as a main component, which has high light transmittance of a transparent oversheet covering both surfaces and excellent physical properties. By using the biaxially stretchable degradable plastic sheet, the pattern printed on the center core looks more beautiful than the conventional transparent sheet material of vinyl chloride. As described above, since it is a composite card material, it also has improved mechanical strength, has the same characteristics and physical properties as a conventional card, and does not have an adverse effect on the environment after disposal. .

[0017]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view of the biodegradable card of the present invention. As shown in the figure, a biodegradation composed of a thermoplastic polymer oversheet (11) whose main component is polylactic acid or a copolymer of lactic acid and oxycarboxylic acid, and a center core (12) of biodegradable plastic It is a sex card (10).

The material of the oversheets (11, 11) is a biodegradable resin made of aliphatic polyester which is a polymer material containing lactic acid as a main component.
As described above, these have degradability and are already used as bioabsorbable materials mainly in the field of medical materials. Examples of lactic acid include D-lactic acid and L-lactic acid, and examples of oxycarboxylic acid include glycolic acid and 6-hydroxycaproic acid. In the present invention, D-lactic acid, L-lactic acid or a mixture thereof and D-lactic acid are used. A thermoplastic decomposable resin containing a copolymer of lactic acid, L-lactic acid or a mixture thereof and glycolic acid or an oxycarboxylic acid represented by 6-hydroxycaproic acid as a main component is used.

The material of the center core (12) is not particularly limited as long as it is biodegradable and has certain physical properties, unlike the material of the transparent oversheet (11). Resins having biodegradability such as natural polymer type and polyester type produced by microorganism by fermentation method can be used. For example, an aliphatic polyester resin chemically synthesized mainly from a polycondensation reaction from glycol and a fatty acid dicarboxylic acid, 3-hydroxybutyric acid · 3
-Polyester produced by microorganisms such as hydroxy-valeric acid copolymer P (3HB-3HV), polycaprolactone (PC
L) and other aliphatic polyesters, polylactic acid and other polyglycolides, polyvinylalool / starch composites, and the like can be used, and a mixture or laminate of these degradable plastics may be used. When left in a natural environment, these biodegradable plastics are preferably decomposed by microorganisms existing in soil or water, and finally decomposed into water, carbon gas, methane and the like. The resin is not limited to the above materials as long as it is a biodegradable resin.

Furthermore, since the above-mentioned resins alone do not provide sufficient mechanical strength and physical properties required for a card, various fillers and additives are added to these resins and kneaded to reinforce and improve the strength of the resins. Quality can be achieved. In addition, increasing the amount of filler is effective in reducing costs. Fillers added to these resins, for example,
Heavy calcium carbonate, light carbonate, calcium carbonate, calcium carbonate, natural silica, kaolin, clay, titanium oxide, barium sulfate, zinc oxide, aluminum hydroxide, alumina, magnesium hydroxide, etc. can be added and kneaded in the amorphous filler. . Also, in the plate-like filler,
For example, talc, mica, glass flakes and the like can be added and kneaded. Further, for example, wollastonite, potassium titanate, basic magnesium sulfate, sepiolite, zonotolite, aluminum borate and the like can be added and kneaded into the needle-shaped filler. Further, spherical fillers can be added, but they do not have the effect of improving the tensile strength, bending strength, impact strength, etc., unlike the fibrous fillers and plate-shaped fillers.

The filler is contained in the resin in an amount of 1 to 50 wt%,
Preferably, 5 to 30 wt% is added and kneaded, and further 2
By performing axial stretching, properties such as rigidity, durability, heat distortion resistance, moldability, impact strength, dimensional stability, and bending resistance can be improved. The above-mentioned fillers can be added alone, but several kinds can be added simultaneously. By adding this filler, it is possible to have properties equivalent to those of conventional vinyl chloride and ABS resin materials. In addition, if necessary, various additives such as 0.05 to 3 parts by weight of an anti-coloring agent and 0.05 to 3 parts of an antioxidant may be used as long as they do not lose the properties of the kneaded resin other than the filler. It is possible to add 3 parts by weight, 0.05 to 3 parts by weight of a lubricant, an organic pigment and an inorganic pigment, and a non-decomposable substance such as a polymer. However, it is not preferable to add a non-decomposable substance in an amount of 30% or more because the decomposability is remarkably reduced and a processing problem occurs.

The method of kneading the above resins includes dry blending, melt blending, and the like, and the method of molding the kneaded resin includes T die extrusion molding and calender roll molding. Sheet-like base materials used for the center core sheet (12) and the oversheets (11, 11) are molded. Further, as described above, the sheet-shaped base material is biaxially stretched under heating and heat-stabilized, whereby the rigidity, formability of the base material,
Properties such as impact resistance, dimensional stability, thermal stability, and bending resistance can be further improved.

As a method of laminating the oversheets (11, 11) on the center core sheet (12), there are dry lamination, wet lamination, heating and pressure melting lamination and the like. By printing the design or the like on the center core sheet and then laminating the design, the printed design can be clearly seen and security is also provided. Further, in the present invention, a filler may be added only to the center core sheet, or an oversheet may be laminated only on one side, in addition to the above laminated structure.

The card base material produced by the above method can be printed / processed in the same manner as in the case of the conventional paper / plastic card, and other patterns and information can be printed on the base material. You can As the printing method, an offset printing method, a screen printing method, a gravure printing method, or the like can be used. Finally the card is 86 ×
A biodegradable card is obtained by punching into a size of 54 mm.

<First Embodiment> A specific embodiment will be described below. Resin (manufactured by Shimadzu Corporation, trade name "Lacty") is extruded to a specified thickness at a processing temperature of 200 ° C by a T-die melt extruder, and then biaxially stretched and calendered to obtain a thickness. A transparent sheet for oversheet having a thickness of 100 μm was produced. After kneading 65 wt% of resin (manufactured by Showa Highpolymer Co., Ltd., trade name: Bionore), Shiragana (manufactured by Shiraishi Industry Co., Ltd., trade name of R06), and 5 wt% of titanium oxide as a filler in a biaxial extrusion kneader , T
Die melt extruder at processing temperature 180 ℃, thickness 50
A 0 μm sheet was molded and further calendered to prepare a center core sheet. A pattern is printed on this center core sheet, and the above oversheets are attached to both sides of the center core sheet to a thickness of 700 μm.
A composite material for m biodegradable card was prepared. Finally, a biodegradable card was obtained by punching with a card cutting die to a size of 86 mm × 54 mm.

Since the oversheets on both sides of this card have good transparency and a light transmittance of 94%, the pattern printed on the center core sheet can be clearly confirmed. Also, when this card was buried in field soil and the decomposition state was observed regularly, it was confirmed that the card started to collapse after 3 months and almost half after 6 months.

Comparative Example 1 A vinyl chloride card having a thickness of 760 μm was embedded in soil and the condition was observed periodically. After 6 months, the color of the card gradually changed to yellow but the shape was retained and decomposed. Confirmed that it has not been done.

[0028]

INDUSTRIAL APPLICABILITY In the biodegradable card of the present invention, the entire card is biodegradable and the oversheet is a plastic resin containing polylactic acid or a copolymer of lactic acid and oxycarboxylic acid as a main component having excellent transparency. By adopting
The pattern printed on the center core was clearly visible, and a high-grade biodegradable card was obtained. In addition, the biodegradable card is manufactured by a composite method, and has excellent characteristics such as moldability, mechanical strength, and physical properties. Moreover, it can be disposed of biodegradable in soil or compost, and has no adverse effect on the environment. The card will not be given. Further, since the present invention is a card composed of a composite material, it also has improved mechanical strength, particularly has the same mechanical characteristics and physical properties as a vinyl chloride card, and does not adversely affect the environment after disposal. Becomes Further, since a large amount of filler can be added to the center core sheet and the amount of expensive biodegradable resin material can be reduced, various effects such as cost reduction of the biodegradable card can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a biodegradable card of the present invention.

[Explanation of symbols]

 10 ... Biodegradable card 11 ... Oversheet 12 ... Center core

Claims (3)

[Claims] 1. A biodegradable plastic card composed of multiple layers, wherein a plastic sheet having at least biodegradability is used as a center core, and a heat containing polylactic acid or a copolymer of lactic acid and oxycarboxylic acid as a main component is provided on both sides of the center core. A biodegradable card characterized by laminating an oversheet made of a plastic polymer. 2. The biodegradable card according to claim 1, wherein the resin of each layer of the biodegradable card contains a filler and an additive. 3. The biodegradable card according to claim 1 or 2, wherein the resin of each layer of the biodegradable card is biaxially stretched.