JP3149356B2 - Biodegradable card base material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a biodegradable card base material. More specifically, the present invention relates to a biodegradable card base material having a core layer (A) and a skin layer (B) which have excellent strength, rigidity, and embossable character for embossing, and can be decomposed by microorganisms in the natural world.

[0002]

2. Description of the Related Art In recent years, various cards such as credit cards, cash cards, consultation tickets, ID cards, prepaid cards, telephone cards, and commuter passes have been widely used in daily life. Such a card provides a core layer (A) made of a resin, paper, or the like, which imparts strength and rigidity, with a surface glossiness (beautifulness), a film having a protection property of a print layer, and a retention property of information recording. In general, a card substrate formed by laminating a skin layer (B) made of a coating resin is cut into a card shape and molded.

Conventionally, such cards, for example, thick cards such as cash cards and credit cards, have a core layer (A) made of polyvinyl chloride having both surfaces printed and, if necessary, a surface layer. A card substrate formed by laminating a skin layer (B) made of polyvinyl chloride obtained by thermocompression bonding a magnetic stripe is cut into a card shape, and if necessary, embossed characters and the like are imprinted on the card surface and stamped. It is usually used (debossed) or hot stamped on a photograph or the like. On the other hand, as a thin card such as a prepaid card, a telephone card or the like which does not require an engraving, a card in which a card base material made of a resin such as polyethylene terephthalate is cut into a card shape is used. A card base made of such a resin as polyvinyl chloride, polyethylene terephthalate, or the like is cut into a card shape, molded, and used as a card according to the purpose of use, period of use, and frequency of use. I have.

[0004]

However, a card made of such a resin as polyethylene terephthalate, polyvinyl chloride or the like, for which the purpose of use has been completed, or
A molding loss or the like generated when a card substrate made of a resin such as polyethylene terephthalate or polyvinyl chloride is cut into a card shape to mold a card or the like is burned with refuse or landfilled. In the case of burning, a card base material or the like made of such a resin has a high calorific value and tends to damage an incinerator. Also, when landfilling,
Resins such as polyethylene terephthalate and polyvinyl chloride have a problem that they are not decomposed in soil and remain in the soil without being decomposed. Furthermore, when a pulp is collected from a card substrate made of paper coated with a resin, the resin does not decompose in an alkaline solution, so it is necessary to take out and separate only the paper.

[0005] Some cards have, for example, a heat-sensitive recording layer and a magnetic recording layer, and a thick card or the like, which is engraved as necessary, requires recording and holding information. In many cases, portable use is required, so that excellent strength, rigidity, durability, and impact resistance enough to withstand embossed characters and the like imprinted as required are required.

The present invention solves the above problems, and has excellent surface gloss, surface protection, strength, rigidity, and excellent embossed character or the like for engraving as required, and can be used in the natural world. It is an object of the present invention to provide a card base material that is biodegraded by microorganisms or the like. At this time, embossed characters (including signs and symbols) applied to a card formed by cutting (for example, punching into a card shape) the card base material
Is imprinted by an imprinter, for example, on a sales voucher, a bank CD, an ATM journal voucher, or the like to copy embossed characters or the like on the voucher as a visible proof that the card has been used.

[0007]

The present invention is characterized in that 90 to 40% by weight of a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate and 10 to 60% by weight of polylactic acid are essential components. A skin layer (B) composed of a composition containing 95-60% by weight of polylactic acid and 5-40% by weight of polycaprolactone as essential components is laminated on both sides of a core layer (A) composed of the composition. An object of the present invention is to provide a degradable card base material.

In the biodegradable card base material, the core layer (A) essentially contains 90 to 40% by weight of a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate and 10 to 60% by weight of polylactic acid. The core layer (A) may be composed solely of a composition as a component, and other components may be further blended as long as the properties of the core layer (A) are not impaired. Also, the skin layer (B)
May be composed solely of a composition containing 95-60% by weight of polylactic acid and 5-40% by weight of polycaprolactone as long as it does not impair the properties of the skin layer (B). May be blended. The composition ratio of the composition constituting the core layer and the skin layer in the core layer (A) and the skin layer (B) is usually at least 50% by weight, more preferably at least 70% by weight, further preferably at least 90% by weight. It is.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate used for the core layer (A) of the biodegradable card base material includes:
Microorganisms such as the hydrogen bacterium Alcaligenes eu
melting point 100-
An example is an aliphatic polyester-based biodegradable resin at 180 ° C. As such a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate, in consideration of processability,
The content of 3-hydroxyvalerate is preferably 1 to 20 mol%. When the content of 3-hydroxyvalerate is less than 1 mol%, the crystallinity tends to be hard and brittle because of high crystallinity, and when it exceeds 20 mol%, the crystallinity and melting point tend to decrease and tend to soften. The values are not particularly limited.

The core layer (A) of the biodegradable card base material
As the polylactic acid used for the skin layer (B), for example, a polymer obtained by directly dehydrating polycondensation of any of L-lactic acid, D-lactic acid, and D, L-lactic acid, or a polylactic acid, , Other hydroxycarboxylic acids (e.g., glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3
-Hydroxyvaleric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid, etc.) or a polymer obtained by ring-opening polymerization of lactide which is a cyclic dimer of lactic acid. A copolymerizable monomer of the above-mentioned lactide and a cyclic ester intermediate of hydroxycarboxylic acid (eg, dimer of glycolic acid (glucolide), caprolactone which is a cyclic ester of 6-hydroxycaproic acid) And a copolymer obtained by ring-opening polycondensation. As can be seen from this, polylactic acid is
It includes all lactic acid-based polymers, and of course, copolymers. One or more of these polylactic acids can be used as appropriate.

In the case of direct dehydration polycondensation, the above lactic acid or lactic acid and another hydroxycarboxylic acid are azeotropically dehydrated and condensed in the presence of, for example, an organic solvent, particularly a phenyl ether-based solvent, and the solvent is distilled off by azeotropic distillation. A method of returning a substantially anhydrous solvent to a reaction system by removing water can obtain a high-molecular-weight polylactic acid having excellent strength for polymerization, but is not particularly limited to the above method. At this time, the number average molecular weight (Mn) of the polylactic acid according to the present invention is not particularly limited,
The number average molecular weight (Mn) is preferably about 50,000 to 1,000,000. If the number average molecular weight (Mn) is less than 50,000, the strength tends to be weak, and if it exceeds 1,000,000, the moldability tends to be poor.

The polycaprolactone constituting the skin layer (B) according to the present invention is preferably a cyclic monomer such as ε.
The aliphatic polyester represented by the chemical structural formula-[O- (CH2) 5-CO] n- obtained by ring-opening polyaddition of -caprolactone with an organometallic compound catalyst can be exemplified. Among such polycaprolactones, the Vicat softening temperature (JI
SK-7206) 100 ° C. or higher is preferred. If the Vicat softening temperature is lower than 100 ° C., the heat resistance tends to be poor and the moldability tends to decrease. The number average molecular weight is Mn =
A biodegradable resin having a molecular weight of 1,000 to 120,000 is preferred. If the number average molecular weight (Mn) is less than 1,000, strength and rigidity tend to be low. If it exceeds 120,000, moldability tends to be poor. is there. However, the values shown above are not particularly limited. At this time, a composition of the above polycaprolactone and an aliphatic polyester (an aliphatic polyester other than polycaprolactone) for increasing the Vicat softening temperature is also included in the category of the polycaprolactone according to the present invention.

[0013] In the biodegradable card base material according to the present invention, the core layer (A) comprises the above-mentioned 3-hydroxybutyrate and 3
-A composition comprising a hydroxyvalerate copolymer and polylactic acid as essential components. The mixing ratio of such a composition is such that the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate is 90 to 40% by weight, and the content of polylactic acid is 10 to 10% by weight.
60% by weight is preferred. 3-hydroxybutyrate and 3
When the copolymer of hydroxyvalerate is less than 40% by weight (polylactic acid is more than 60% by weight), the solvent resistance is poor,
When the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate exceeds 90% by weight (polylactic acid is less than 10% by weight), strength, rigidity and impact strength are reduced. Not preferred. Incidentally, such a single-layer biodegradable card substrate composed of only the core layer (A) is not practical because of imbalance in mechanical strength in the vertical and horizontal directions, and such a core layer (A) is not practical. The skin layer (B) according to the present invention compensates for the weakness of the core layer (A) by providing the skin layer (B) according to the present invention. ) Is a practically biodegradable card base material for the first time.

The other core layer (A) in the biodegradable card base material according to the present invention may be the same as that described above for use in the skin layer (B) for the purpose of improving the above-mentioned mechanical strength imbalance. The same polycaprolactone may be added to the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate, polylactic acid and polycaprolactone in an amount of 23% by weight or less based on all the polymer components. At this time, if the polycaprolactone content exceeds 23% by weight, the engraving properties of, for example, embossed characters applied to the card surface tend to be poor.

Further, the biodegradable card base material according to the present invention comprises, as another core layer (A), a copolymer of the above-mentioned 3-hydroxybutyrate and 3-hydroxyvalerate and polylactic acid. Is preferred, but in addition to this, the monolayer, a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate, polylactic acid and polylactic acid It may have a multilayer structure in which a layer made of a composition containing caprolactone is laminated.

[0016] In the biodegradable card base material according to the present invention, the skin layer (B) comprises a composition comprising the above-mentioned polylactic acid and polycaprolactone as essential components,
Laminated on both surfaces of the core layer (A) that constitutes the biodegradable card base material, the printed surface applied to the surface of the core layer (A) is protected, and in order to make the print look more clear, It tends to contribute to the improvement of the engraving property of embossed characters and the like, the adhesive property of a magnetic stripe, and the hot stamping property of characters, designs, photographs and the like.

Further, the biodegradable card base material according to the present invention is formed by cutting into a card shape, for example, and is used as necessary for a biodegradable card such as a cash card and a credit card. Generally, embossed characters or the like are stamped on the card surface. Such embossed characters and the like are usually 43 mm from the surface of the skin layer (B).
It is preferable that the stamp is formed so as to have a height of 0 μm or more and 480 μm or less. If the height is less than 430 μm, for example, copying of a journal slip or the like tends to be unclear,
If it is engraved so as to exceed 80 μm, cracks, cracks, and the like tend to occur in embossed characters and the like, and cards tend to warp.

The blend ratio of polylactic acid and polycaprolactone constituting the skin layer (B) of the biodegradable card base material according to the present invention is 95-60% by weight of polylactic acid and 5-40% by weight of polycaprolactone. Is preferred. If the content of polycaprolactone is less than 5% by weight (polylactic acid is more than 95% by weight), the skin layer (B) tends to be brittle, and the content of polycaprolactone exceeds 40% by weight (polylactic acid is less than 60% by weight). And the rigidity tends to decrease, which is not preferable.

The biodegradable card base material according to the present invention comprises
Core layer (A) comprising a composition comprising a copolymer of hydroxybutyrate and 3-hydroxyvalerate and polylactic acid as essential components, and skin layer comprising a composition comprising polylactic acid and polycaprolactone as essential components (B) and (B)
/ (A) / (B) three-layer structure, or (B) / (A)
A four-layer configuration of / (A) / (B) can be mentioned as a preferable configuration.

The biodegradable card base material according to the present invention is (B)
In the case of the four-layer configuration of / (A) / (A) / (B), when it is necessary to perform printing on both sides of the core layer, for example, one of the two core layers can be printed without performing complicated double-sided printing. An image or the like is appropriately printed on one surface of one core layer (A) and one other core layer (A), and the printed surface of each core layer (A) has two skin layers (B). The biodegradable card substrate having printing on both sides can be easily obtained by laminating the non-printing surfaces of the core layer (A) so as to be in contact with each other.

Specifically, for example, first, at least two core layers (A) comprising a composition containing a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate and polylactic acid as essential components, At least two skin layers (B) comprising a composition containing polylactic acid and polycaprolactone as essential components are individually molded. Next, for example, on one surface of each of the two core layers (A),
Images are printed by the silk screen method. The two core layers (A) for which printing has been completed are one core layer (A)
Is arranged so that the printed surface of the core layer (A) is in contact with the printed surface of another core layer (B), and the printed surface of the other core layer (A) is in contact with the other skin layer (B). The non-printed surfaces of the core layer (A) are opposed to each other, and the core layer (A) is sandwiched with the skin layer (B) so that (B) / (A) / (A) / (B). A bonded biodegradable card substrate is created. The sandwiched biodegradable card base material in an unbonded state is sandwiched between, for example, a mirror surface plate, and is pressurized, heated, and cooled to easily form a biodegradable card base material having print layers on both sides. A method can be exemplified.

The biodegradable card base material according to the present invention is not particularly limited. For example, the core layer (A) and the skin layer (B)
And a co-extrusion method in which the layers (A) and (B) are laminated using a co-extrusion die connected to at least two extruders, or
At least two types of biodegradable card substrates, for example (A)
For example, a method in which a layer and a layer (B) are separately formed and laminated by a thermocompression bonding method can be exemplified.

Among these methods, a core layer (A) comprising a composition comprising a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate and polylactic acid as essential components
And a skin layer (B) composed of a composition containing polylactic acid and polycaprolactone as essential components are separately formed by, for example, a T-die method, and thereafter, one or two core layers (A) With two skin layers (B), for example, a layer (B) /
(A) layer / (B) layer or (B) layer / (A) layer /
(A) layer / (B) layer is sandwiched to form an unbonded biodegradable card base material, and the sandwiched non-bonded biodegradable card base material is, for example, made of metal. A preferred example is a thermocompression bonding method in which the layers are sandwiched by mirror plates, pressed, heated, cooled, and laminated. At this time, the pressure is 5 to 40 kg / cm 2 and the heating temperature is 140 to 190 ° C.
Can be exemplified, but there is no particular limitation.

The biodegradable card base material having the constitutions (B) / (A) / (B) and (B) / (A) / (A) / (B) according to the present invention may be used as it is. The one in which the skin layer (B) is uniaxially or biaxially stretched may be used, and there is no particular limitation. By stretching the skin layer (B),
In addition, the rigidity is increased, and when folded, it can be prevented from being broken. Further, if necessary, the film may be heat-set after stretching. Heat setting tends to improve the balance of mechanical strength.
Although there is no particular limitation on the stretching method, for example, sequential biaxial stretching in which longitudinal stretching is performed and then transverse stretching can be exemplified as a preferred example. The stretching temperature and the stretching ratio are not particularly limited, but the stretching temperature is preferably from 40 to 80 ° C., and the stretching ratio is preferably from 3.0 to 4.0 in both the longitudinal and transverse directions. Examples of the heat setting temperature include fixing at 100 to 130 ° C. for about 25 to 120 seconds.

In the biodegradable card base material according to the present invention, for example, when the biodegradable card base material is used for a thick card, the core layer (A) has a thickness of 720 to 480 μm and the skin layer (B) Is preferably 20 to 140 μm. When the biodegradable card base material is used for, for example, a thin card, the thickness of the core layer is preferably 50 to 210 μm, and the thickness of the skin layer is preferably 20 to 100 μm. No restrictions.

Specifically, as a thick card base material,
For example, it has a magnetic recording retention of information, an engraving aptitude for embossed characters (including a sign and a symbol) provided as needed, and is frequently used for a long period of time.
For example, it is suitably used for a cash card, a credit card, etc., and the core layer (A) is a single monolayer or two layers.
The configuration of two or more layers of at least two sheets, for example, the thickness of the core layer may be 240 to 360 μm, and there is no particular limitation. The thin card base material is not particularly limited, but does not need to be imprinted with embossed characters or the like, and is suitably used for telephone cards, prepaid cards, and the like which are used for a relatively short period of time.

The biodegradable card base material according to the present invention comprises a composition comprising, as essential components, a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate, which constitutes the core layer (A), and polylactic acid. The composition containing polylactic acid and polycaprolactone as the essential components constituting the skin layer (B) may optionally contain additives and fillers such as heat stabilizers, antioxidants, light stabilizers, and antistatics. Agent, lubricant, antibacterial agent,
Pigments or dyes, titanium oxide, calcium carbonate, barium sulfate, calcium hydroxide, mica, talc and the like can be added. In addition, other thermoplastic resins and the like can be blended as needed as long as biodegradability is not impaired, and there is no particular limitation. The other thermoplastic resin described above is not particularly limited, and examples thereof include other biodegradable resins, such as poly-3-hydroxybutyrate, poly-3-hydroxyvalerate, and 3-hydroxybutyrate. A copolymer of 3-hydroxypropionate, a copolymer of 3-hydroxybutyrate and 4-hydroxybutyrate, a poly-3-hydroxyalkanoate, and the like can be blended as necessary.

The biodegradable card base material according to the present invention comprises a composition comprising, as essential components, a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate constituting the core layer (A), and polylactic acid. The method for preparing the composition comprising polylactic acid and polycaprolactone as the essential components constituting the skin layer (B) is not particularly limited, and is generally used in a conventional method for producing a composition such as a polyolefin resin. Way,
For example, a method of blending with a ribbon blender, a Hensel mixer, a tumbler, etc., a method of kneading using a kneader such as a kneader, a Banbury mixer, a roll, etc., and a method of heating and melting and kneading using a single-screw or twin-screw extruder are exemplified. it can.

The biodegradable card base material according to the present invention can be provided with a printing layer and a heat-sensitive recording layer as required. In this case, it is preferable to provide between the surface of the core layer (A) and the skin layer (B) or between the layers. In the case of a magnetic card,
The magnetic stripe is preferably formed by an appropriate method before or after cutting on the surface of the skin layer (B). Further, for example, in the case of manufacturing a thick cash card, a credit card, or the like, if necessary, for example, after cutting into a card shape, embossed characters (including signs and symbols) are engraved on the card surface by an appropriate method. Is preferred, but there is no particular limitation.

When the biodegradable card base material according to the present invention is cut into, for example, a card, sufficient bending strength, tensile strength, impact strength, softening temperature, lamination property, heat resistance, heat stretching resistance, It has adhesiveness, chemical immersion resistance and moisture resistance, and has biodegradability that can be decomposed by microorganisms in nature.

[0031]

【Example】

Hereinafter, the present invention will be described in detail with reference to examples. However, needless to say, the present invention is not limited to the following embodiments. In the following examples, measurement and evaluation of each inspection item were performed by the following methods.

[Tensile strength (kg / cm 2)]: JIS
Measured with an autograph according to X-6301,
kg / cm2 or more. [Impact strength]: According to JIS X-6301, the card was placed on a firm horizontal plate, a 500 g steel ball was dropped on the card from a height of 30 cm, and the card was visually evaluated for cracks and cracks. [Flexible temperature]: The flexible temperature of the card is measured with a high-temperature hot-air dryer according to JIS X-6301, and it is 52 ° C. or more. [Lamination property]: When the card is immersed in liquid paraffin at 150 ° C. for 5 minutes according to JIS X-6301,
The occurrence of a gap between the card stacks was visually evaluated. [Heat resistance]: According to JIS X-6301, the card was immersed in warm water at 60 ° C. for 5 minutes, and the change of the card surface was visually evaluated. [Heat resistant stretchability]: According to JIS X-6301, the card was left at room temperature for 30 minutes at -10 ° C and + 45 ° C, then returned to room temperature and left for 2 hours. Must be: [Tackiness]: According to JIS X-6301, the card was subjected to a pressure of 50 g / cm @ 2 in an atmosphere of 40 DEG C. and 90% RH, and the appearance change after 48 hours was visually evaluated. [Chemical immersion resistance]: According to JIS X-6301
Put the curd in 5% saline, 1% aqueous sodium carbonate, 5%
% Of acetic acid aqueous solution for 24 hours was visually evaluated. [Moisture resistance]: According to JIS X-6301, the appearance change after storing the card in an atmosphere of 40 ° C. and 90% RH for 48 hours was visually evaluated. [Height of embossed character from card surface]: 430 to 48
The sample having a size of 0 μm was rated as ○, and the sample outside the range of 430 to 480 μm was rated as x. [Deformability]: The occurrence of “warpage” due to embossed character marking was visually evaluated. [Biodegradability]: A biodegradable card base material with a size of 85.5 × 54 mm was immersed in treated sludge (25 ° C.) collected and treated at the Purification Center (in Shiga Prefectural Sewerage Corporation Konan Central Office).
After 28 days, it was taken out and the weight loss rate was measured and evaluated.

Example 1 In a biodegradable card base material having a four-layer structure of (B) layer / (A) layer / (A) layer / (B) layer: [Formation of core layer (A)] core The layer (A) is formed by ring-opening polymerization of 49% by weight of a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate having a 3-hydroxyvalerate content of 8 mol% and lactide of L-lactic acid. A composition containing 49% by weight of polylactic acid having a number average molecular weight of Mn = 200,000 and 2% by weight of titanium oxide is melted and kneaded using a T-die extruder set at a cylinder temperature of 190 ° C. and a die temperature of 190 ° C. Then, a sheet having a thickness of 280 μm extruded on a cooling roll having a surface temperature of 40 ° C. was used.

[Formation of Skin Layer (B)] Skin Layer (B)
As a result, 79.96% by weight of polylactic acid having a number average molecular weight Mn = 100,000 obtained by ring-opening polymerization of lactide of L-lactic acid, a Vicat softening temperature of 104 ° C., and a number average molecular weight Mn =
A composition containing 20% by weight of polycaprolactone (80,000) and 0.04% by weight of blue pigment was supplied to a T-die extruder set at a cylinder temperature of 210 ° C. and a die temperature of 200 ° C., and was melted and kneaded. The sheet was extruded on a cooling roll having a surface temperature of 60 ° C., and a sheet having a thickness of 100 μm was used.

[Formation of Biodegradable Card Substrate] An image is printed on the surface of each of the two sheets to be the core layer (A) obtained above using an offset printing machine, and one core layer (A) is formed. ) Is superimposed so that one skin layer (B) obtained above is in contact with the printed surface of (a), and another skin layer (B) is printed on the printed surface of another core layer (A). They were superimposed so that they touched each other. Thereafter, the non-printing surfaces of the core layer (A) having the (A) / (B) configuration in which the core layer (A) and the skin layer (B) are overlapped with each other are opposed to each other, and the (B) layer / Four sheets were arranged in a sandwich form so as to be (A) layer / (A) layer / (B) layer to obtain an unbonded biodegradable card base material. The obtained biodegradable card substrate in the non-adhered state is sandwiched between, for example, two metal mirror plates, and then heated to 170 ° C. for 20 minutes.
The temperature was raised to 170 ° C., and thermocompression bonding was performed for 5 minutes at a pressure of 10 kg / cm 2 at a temperature of 170 ° C., and cooled to 40 ° C. over 20 minutes to obtain (B) / (A) / (A) / (B) = 100. / 280/2
A biodegradable card substrate of 80/100 = 760 μm was molded.

[Evaluation of Biodegradable Card Substrate] The biodegradable card substrate having a four-layer structure of (B) layer / (A) layer / (A) layer / (B) layer obtained above was formed into a card. Then, embossed characters such as letters, symbols, and signs forming the convex portions were stamped on the card formed as described above using a thin plate having unevenness on the card surface. As a result, no cracks in the embossed characters, cracks, warpage of the card, etc. were recognized. Further, the biodegradable card base material was placed in the returned sludge at 28 ° C at 25 ° C.
The weight loss after immersion for 5 days was 5% or less.
Further, if the biodegradable card substrate is continuously immersed in the above state, after several months, the weight loss rate increases, and water,
It is presumed to be decomposed into carbon dioxide gas. Tensile strength, impact strength, softening temperature, laminability of the biodegradable card substrate,
Heat resistance, heat stretch resistance, chemical immersion resistance, adhesiveness, moisture resistance,
Table 1 shows the height of the embossed characters and the presence or absence of warpage due to the embossed character engraving.

[0038]

[Table 1]

Example 2 In a biodegradable card base material composed of three layers (B) / (A) / (B): [Preparation of core layer (A)] As the core layer (A), 3-hydroxy was used. 49% by weight of a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate having a valerate content of 8 mol%, and a copolymer obtained by directly dehydrating and polycondensing L-lactic acid and glycolic acid. Average molecular weight Mn = 100,0
A composition comprising 49% by weight of polylactic acid and 2% by weight of titanium oxide was melted and kneaded with a T-die extruder set at a cylinder temperature of 190 ° C. and a die temperature of 190 ° C.
Extruded on a cooling roll with a surface temperature of 40 ° C, thickness 5
A 60 μm sheet was used.

[Formation of Skin Layer (B)] Skin Layer (B)
A number average molecular weight Mn = 100,0 which is a copolymer obtained by directly dehydrating and polycondensing L-lactic acid and glycolic acid.
79.96% by weight of polylactic acid of 00, Vicat softening temperature 1
A composition containing 20.0% by weight of polycaprolactone having a number average molecular weight of 80,000 and a blue pigment of 0.04% by weight was set at a cylinder temperature of 210 ° C and a die temperature of 200 ° C. A sheet having a thickness of 100 μm was supplied to a T-die extruder, melt-kneaded, and extruded on a cooling roll having a surface temperature of 60 ° C.

[Formation of Biodegradable Card Substrate] At least one surface of the sheet to be the core layer (A) was printed with a pattern or the like using an offset printing machine. After printing is completed,
The sheet to be the core layer (A) is sandwiched and overlapped with the two sheets to be the skin layers (B) in a non-adhesive form having a layer (B) layer / (A) layer / (B) layer configuration. A degradable card base material was obtained. The unbonded biodegradable card base material is sandwiched between metal mirror plates, and pressed and pressed in the same manner as in Example 1.
Heating, cooling and laminating (B) / (A) / (B) = 100
/ 560/100 μm = 760 μm biodegradable card base material was obtained.

[Evaluation of biodegradable card base material] The biodegradable card base material obtained above was cut into a card shape in the same manner as in Example 1 to form a card.
Next, embossed characters were stamped on the surface of the card. As a result, cracks in the embossed characters, cracks, warpage of the card, and the like were not observed. Further, the rate of weight loss after immersing the biodegradable card base material in returned sludge in the same manner as in Example 1 was 5% or less. Further, if the biodegradable card base material is continuously immersed in the above state, it is presumed that after several months, the weight loss rate will increase and the biodegradable card base material will be decomposed into water, carbon dioxide gas and the like. Tensile strength, impact strength, softening temperature, lamination property, heat resistance, heat-resistant stretchability, chemical immersion resistance, adhesiveness, moisture resistance, embossed character height, emboss of the biodegradable card substrate Table 1 shows the presence or absence of warpage due to the character stamp.

Example 3 As a skin layer (B), a 900 μm thick sheet obtained in the same manner as in Example 1 was stretched at a stretching temperature of 60 ° C. and a stretching ratio (length × width) = 3.0 × 3.0. (B) / (A) / (B) = 100/560 / in the same manner as in Example 2 except that a sheet having a thickness of 100 μm which was successively biaxially stretched under the same conditions was used.
A biodegradable card substrate of 100 μm = 760 μm was formed. A card was formed by punching the biodegradable card base material into a card shape, and then embossed characters were stamped on the card surface in the same manner as in Example 1. As a result, cracks in the embossed characters, cracks, warpage of the card, and the like were not observed. In addition, as in the examples, the biodegradable card base material had a weight reduction rate of 5% or less after being immersed in activated sludge. Further, if the biodegradable card base material is continuously immersed in the above-mentioned state, it is presumed that after several months, the weight loss rate increases, and the biodegradable card base material is decomposed into water, carbon dioxide gas and the like. Tensile strength, impact strength, flexibility temperature, lamination property, heat resistance, heat-resistant stretch property, chemical immersion resistance, adhesiveness, moisture resistance, embossed character height, embossed character of the biodegradable card substrate The presence or absence is shown in Table 1.

Example 4 The core layer (A) was composed of 50% by weight of a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate having a content of 3-hydroxyvalerate of 8 mol% and L-lactic acid. Number average molecular weight Mn = 100,00 which is a polymer obtained by ring polymerization
0 polylactic acid of 32% by weight, number average molecular weight Mn = 80,
(B) / (A) / (B) = 1 in the same manner as in Example 2 except that the layer was composed of a composition comprising 16% by weight of polycaprolactone and 2% by weight of titanium oxide.
A biodegradable card base material of 00/560/100 μm = 760 μm was obtained. A card is formed by punching the biodegradable card base material into a card shape, and then on the card surface,
Embossed characters were stamped in the same manner as in Example 1. As a result, cracks in the embossed characters, cracks, warpage of the card, and the like were not observed. The weight loss rate after immersing the biodegradable card base material in activated sludge in the same manner as in Example 1 was 5%.
% Or less. Further, if the biodegradable card base material is continuously immersed in the above state, it is presumed that after several months, the weight reduction rate will increase and the biodegradable card base material will be decomposed into water, carbon dioxide gas and the like. Tensile strength of the biodegradable card substrate, impact strength, softening temperature, laminability, heat resistance, heat-resistant stretch, chemical immersion resistance,
Table 1 shows the adhesiveness, the moisture resistance, the height of the embossed characters, and the presence or absence of warpage due to embossed character engraving.

Comparative Example 1 80% by weight of a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate having a 3-hydroxyvalerate content of 8 mol%, a Vicat softening temperature of 104 ° C., an average molecular weight of 80, 000 polycaprolactone 20% by weight is melted, kneaded and extruded with a T-die extruder set at a die temperature of 170 ° C., cooled with a cooling roll having a surface temperature of about 40 ° C., and biodegraded to a thickness of 760 μm. A curable base material was obtained. A card was formed by punching out the biodegradable card base material obtained above into a card shape, and then embossed characters were stamped on the card surface in the same manner as in Example 1. As a result, the height of the embossed character from the card surface is 300
μm or less. Therefore, when the card is used, for example, copying to a sales slip by an implicator is insufficient. Tensile strength, impact strength, flexibility temperature, lamination property, heat resistance, heat-resistant stretch property, chemical immersion resistance, adhesiveness, moisture resistance, embossed character height, embossed character of the biodegradable card substrate The presence or absence is shown in Table 1.

[0046]

The biodegradable card base material according to the present invention has extremely excellent tensile strength, impact strength, flexible temperature, laminability, heat resistance, heat-resistant stretchability, chemical immersion resistance, adhesiveness, and moisture resistance. Have Therefore, since the biodegradable card molded by using the biodegradable card base material has extremely excellent rigidity, for example, a thick credit card, cash card, etc. It can be suitably used for thin prepaid cards, telephone cards, and the like that do not require engraving. Furthermore, when buried in the ground as waste, it is decomposed into water, carbon dioxide, and the like in a relatively short period of time by microorganisms in the natural world.

Continuation of the front page (56) References JP-A-5-42786 (JP, A) JP-A-7-266751 (JP, A) JP-A-7-267671 (JP, A) JP-A-7-285197 (JP, A) JP-A-8-175658 (JP, A) JP-A-8-176421 (JP, A) JP-A-8-230365 (JP, A) JP-A-8-263619 (JP, A) JP-A-8-267968 (JP, A) JP-A-8-281878 (JP, A) JP-A-8-290692 (JP, A) JP-A 8-290693 (JP, A) JP-A-9-131835 (JP, A) A) JP-A-9-188077 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B42D 15/00 B42D 15/10 B32B 27/00 C08L 67/00

Claims (8)

(57) [Claims] 1. A core layer (A) comprising a composition comprising 90 to 40% by weight of a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate and 10 to 60% by weight of polylactic acid as essential components. On both sides, 95-60% by weight of polylactic acid,
A biodegradable card base obtained by laminating a skin layer (B) comprising a composition containing 5 to 40% by weight of polycaprolactone as an essential component. 2. The method according to claim 1, wherein the core layer (A) and the skin layer (B)
The biodegradable card base material according to claim 1, which has a three-layer constitution of (B) / (A) / (B). 3. The core layer (A) and the skin layer (B)
The biodegradable card base material according to claim 1, which has a four-layer constitution of (B) / (A) / (A) / (B). 4. The core layer (A) comprises a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate and a polylactic acid in a total amount of 77% by weight or more, and polycaprolactone 23.
2. A composition comprising, as an essential component, at most 1% by weight.
4. The biodegradable card base material according to any one of claims 1 to 3. 5. The method according to claim 1, wherein the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate contains 1 to 20 mol% of 3-hydroxyvalerate. Biodegradable card base material. 6. The biodegradation according to claim 1, wherein the polylactic acid is a polymer obtained by directly dehydrating and polycondensing any of L-lactic acid, D-lactic acid and D, L-lactic acid. Card base material. 7. The polylactic acid according to claim 1, wherein the polylactic acid is a copolymer obtained by directly dehydrating polycondensation of any of L-lactic acid, D-lactic acid and D, L-lactic acid with hydroxycarboxylic acid. 2. The biodegradable card base material according to 1. 8. The polylactic acid according to claim 1, wherein the polylactic acid is a polymer obtained by ring-opening polymerization of lactide obtained from any of L-lactic acid, D-lactic acid and D, L-lactic acid. Biodegradable card base material.