JP2009282407A - Hologram label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: in the conventional biodegradable hologram seal which can be easily biodegraded by burying in soil so as to avoid not only problems of appearance but bad influences on the ecosystem when used seals are discarded, a non-biodegradable resin is used for the adhesive and a hologram image remains indefinitely. <P>SOLUTION: On a biodegradable plastic film 1 (or sheet), a reflective thin film layer, a hologram relief, and a biodegradable adhesive layer are formed in this order. Thus, the hologram image does not remain indefinitely and the whole label decomposes rapidly. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an environmentally friendly hologram label that can form a clear hologram image, is easy to dispose of after being used, has no fear of pollution due to disposal, and does not adversely affect the natural environment, More specifically, the present invention relates to a hologram label in which both the base material and the pressure-sensitive adhesive constituting the hologram label are biodegradable, and all are quickly decomposed after disposal.

  In the present specification, “part” indicating the formulation is based on mass. The “hologram” includes a hologram and a hologram having a light diffractive function such as a diffraction grating.

  (Main use) The main use of the hologram label of the present invention is a hologram label used in the field of anti-counterfeiting or design, and specifically, gift certificates, cash vouchers, cards, prizes, manufacturing. Authentic certification label that proves that it is a manufacturer's genuine product, etc., or a field that increases the added value of the product, such as improving the designability by attaching a label or indicating that the product is expensive, especially It is suitable for the field where the impact on the environment should be considered or taken into consideration in the disposal treatment after used.

  (Background Art) Holograms that reproduce stereoscopic images using light interference require advanced manufacturing technology and can be formed in various forms, such as labels, seals, and foils. As a means of preventing counterfeiting, it is used for gift cards, gift certificates, various cards such as certificates, identification cards, books, digital video discs and other works, sports equipment, branded goods, and genuine materials such as toner cassettes. It is used by sticking to various products such as limited products.

  Thus, the hologram is suitable for determining whether it is genuine or counterfeit at first glance, and since it is difficult to manufacture, it is widely used for preventing counterfeiting and for providing security. In addition, as described above, the hologram can display a three-dimensional image and has a high-class feeling, and is therefore widely used in general products.

  Products using these holograms, particularly hologram products used as labels and stickers, are disposed of together with the product when the target product to which the hologram is attached is used. The target product itself to which the hologram is attached has been improved in consideration of the environment and has been improved into an environmentally friendly material. Therefore, it is necessary to make the hologram product an environmentally friendly material.

(Prior art)
In order to meet these requirements, plastic films or sheets with biodegradability and transparency are used as the base material / film that forms the hologram, and when the hologram product is buried in the soil, it decomposes naturally. What is made so that it may go is known (for example, refer patent document 1).

  However, the hologram forming material itself formed on the plastic film or sheet uses a thermosetting resin such as an ultraviolet ray or an electron beam curable resin in consideration of the hologram performance, and is buried in the soil. However, only the plastic film or sheet is decomposed, and the hologram forming material is not decomposed. That is, there is a drawback that the hologram image remains without being decomposed.

In order to cope with this problem, a hologram label has been developed in which a hologram image is decomposed when a hologram relief is formed on the biodegradable plastic itself and buried in soil in order to make the hologram forming material itself biodegradable. Yes. (For example, refer to Patent Document 2).

However, because this hologram label is not biodegradable, even if it is buried in the soil, only the plastic film or sheet that is the hologram forming layer is decomposed and adhered to the adhesive and the adhesive. The hologram reflective thin film layer is not decomposed. That is, there is still a drawback that the hologram image remains indefinitely without being decomposed.

JP 2007-79299 A Japanese Patent Laid-Open No. 8-21266

  Therefore, the present invention has been made to solve such problems, and its purpose is to promptly make all the materials carrying the reflective thin film layer constituting the hologram label promptly when buried in the soil. An object of the present invention is to provide a hologram label which is decomposed and the hologram image disappears quickly, which is excellent in environmental considerations and has anti-counterfeiting properties and high design properties.

To solve the above problem,
According to a first aspect of the hologram label of the present invention, a hologram relief is formed on one surface of a transparent biodegradable plastic film or sheet, and a reflective thin film is formed in contact with the hologram relief. An adhesive made of a biodegradable resin is formed on the opposite surface of the transparent biodegradable plastic film or sheet.

According to the hologram label of the first aspect, when buried in soil, a transparent biodegradable plastic film or sheet (hereinafter also referred to as “hologram forming layer”) starts biodegradation. At the same time, the adhesive also starts biodegradation, which proceeds from the surface (exposed surface and side surface) where the hologram-forming layer and the adhesive are in contact with the soil toward the center of the layer and reflects both layers. Since the pressure-sensitive adhesive is in contact with the adherend, the decomposition mainly proceeds along this interface.

Although the reflective thin film is not biodegradable, the relief shape cannot be maintained by the thin film alone, so the hologram forming layer in contact with the thin film and the surface portion of the adhesive are only decomposed. Thus, the hologram deteriorates. That is, even when the hologram forming layer and the entire pressure-sensitive adhesive are not yet decomposed, the hologram relief shape of the reflective thin film is damaged by the progress of decomposition of the interface where both layers are in contact with the thin film. As a result, the reproducibility of the hologram is impaired and the hologram image disappears.

  According to a second aspect of the hologram label of the present invention, in the hologram label of the first aspect, the hologram forming layer and the adhesive are made of the same resin system having biodegradability. It is.

According to the hologram label of the second aspect, when buried in the soil, the hologram forming layer and the adhesive are the same resin system, so whatever the bacterial species of the soil, Similar biodegradation begins and biodegradation proceeds at a similar rate.

Here, when the hologram formation layer and the adhesive are different in resin system, if the state of biodegradation by the bacterial species in the buried soil is greatly different between the hologram formation layer and the adhesive, one layer is Even when the biodegradation is completed, the other layer remains indefinitely, and a phenomenon occurs in which the reflective thin film that reproduces the hologram maintains its shape indefinitely. In addition, after the resin on only one surface of the reflective thin film is lost, the relief shape that is not deteriorated is exposed, leading to an illegal act of duplicating the hologram relief from here.

In order to eliminate this phenomenon, the hologram forming layer and the pressure-sensitive adhesive are made of the same biodegradable resin system, and their degradability is the same. did. This decomposition also proceeds along the upper and lower interfaces of the reflective thin film, and the hologram relief shape is deformed and deteriorated without waiting for the entire resin layer to be decomposed.

Although the reflective thin film itself is not biodegradable, the relief shape cannot be maintained with the thin film itself, and the upper and lower layers of the thin film deteriorate, so that the relief shape is deformed and deteriorated. Therefore, this deformation / deterioration depends on the decomposition rate along the surface (interface) of each layer rather than the decomposition rate in the thickness direction of each layer. This makes it possible to achieve the object by making the composition itself the same system, not adjusting the degree of polymerization and the thickness of the resin used in each layer.

  According to the first aspect of the hologram label of the present invention, when buried in the soil, all the materials carrying the reflective thin film layer constituting the hologram label are rapidly decomposed, and the hologram image disappears quickly. Therefore, there is an effect that a hologram label having excellent environmental considerations, anti-counterfeiting properties, and high design properties is provided.

  Further, according to the second aspect of the hologram label of the present invention, since the hologram forming layer and the pressure-sensitive adhesive are the same biodegradable plastic, in addition to the effects of the first aspect, all the materials are quickly and similarly. There is an effect that the hologram image quickly disappears.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a sectional view of a hologram label A showing an example of an embodiment of the present invention.
FIG. 2 is a sectional view of a hologram label A ′ showing another example of the embodiment of the present invention.

(Transparent Biodegradable Plastic Film or Sheet) The transparent biodegradable plastic film or sheet 1 used in the hologram labels A and A ′ of the present invention is:
As a chemical synthesis system, lactone resins: ε-caprolactone, 4-methylcaprolactone, 3,5,5-trimethylcaprolactone, 3,3,5-trimethylcaprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, enanthate A homopolymer of lactone, a copolymer of these two or more monomers, a mixture thereof, or polycaprolactone is preferred.

Or polybutylene succinate resin: polybutylene succinate adipate, a mixture of polybutylene succinate and polycaprolactone, a mixture of polybutylene succinate and polybutylene succinate adipate, polybutylene succinate adipate and poly A mixture of lactic acid, or polylactic acid, a mixture of polylactic acid and D-lactic acid, or a polyester resin synthesized from a low molecular weight aliphatic dicarboxylic acid and a low molecular weight aliphatic diol, such as succinic acid and butanediol, ethylene glycol A combination of oxalic acid and neopentyl glycol, butanediol, ethylene glycol, etc., a mixture of modified polyvinyl alcohol, aliphatic polyester resin and starch, aliphatic to low molecular weight aliphatic polyester Such as those by polymerizing added isocyanate is preferred.

Natural products include animal natural materials such as gelatin, plant natural materials such as cellulose: starch fatty acid esters, starch chitonan / cellulose, etc., as microbial production systems, polyhydroxybutyrate and polyester systems: as carbon source P based on 3-hydroxypropionic acid, 4-hydroxybutyric acid, γ-butyrolactone (3HB-CO-4HB), propionic acid as carbon source, P based on valeric acid (3HB-CO-3HV) It is.

In addition, polylactic acid, polybutylene succinate / terephthalate copolymer, polyester resin with molecular weight exceeding several hundreds of thousands, poly (3-hydroxybutyric acid) homopolymer accumulated in granular form in the cell, and high crystal A reactive polyester is also used.

The thickness of the transparent biodegradable plastic film or sheet 1 is preferably 10 μm to 200 μm, particularly 20 μm to 40 μm. As the thickness increases, the amount of waste processing increases, and optical loss (decrease in light transmittance and increase in light scattering) also increases, so the thickness can be reduced as much as possible. desirable.

(Reflective thin film) In the hologram labels A and A 'of the present invention, the reflective thin film 2 is formed on one surface of a transparent biodegradable plastic film or sheet 1. Since this thin film needs to reflect incident light, it is not particularly limited as long as it has a higher refractive index than the transparent biodegradable plastic film or sheet 1.
The reflective thin film 2 may be either a metallic gloss reflective layer such as a metal thin film formed by a vacuum thin film method or a transparent reflective layer, or a metallic gloss reflective layer may be provided partially or a transparent reflective layer may be provided. In this case, an image on the adherend covered with the label after sticking can be observed through the hologram.

As a transparent reflective layer, it is almost colorless and transparent, and its optical refractive index is different from that of the hologram forming layer. A simple hologram can be produced. For example, a thin film having a higher refractive index than a hologram forming layer (in the present invention, which corresponds to a transparent biodegradable plastic film or sheet 1), for example, ZnS, TiO ₂ , Al ₂ O ₃ , Sb ₂ There are S ₃ , SiO, SnO ₂ , ITO and the like. Preferably, it is a metal oxide or nitride, specifically, Be, Mg, Ca, Cr, Mn, Cu, Ag, Al, Sn, In, Te, Ti, Fe, Co, Zn, Ge, Pb. Cd, Bi, Se, Ga, Rb, Sb, Pb, Ni, Sr, Ba, La, Ce, Au, and other oxides or nitrides, and the like can be exemplified by a mixture of two or more thereof. Also, a general light-reflective metal thin film such as aluminum can be used with transparency when the thickness is 20 nm or less.

  As with the metal thin film, the transparent metal compound is formed by vapor deposition or sputtering so that the thickness of the transparent biodegradable plastic film or sheet 1 is about 10 to 2000 nm, preferably 20 to 1000 nm. It may be provided by a vacuum thin film method such as ion plating or CVD (chemical vapor deposition). In particular, the CVD method causes little thermal damage to the transparent biodegradable plastic film or sheet 1. Even if other thin film forming methods are used, if the thin film layer to be formed is made thin, the thermal damage can be reduced. For example, in the case of an AL vapor deposition layer, although depending on the formation conditions, approximately 20 nm is a critical point where transparency is lost and total reflection appears. This thickness varies depending on the forming conditions such as the thin film material, the forming method, the metal heating temperature and the degree of vacuum.

(Hologram) Next, predetermined fine unevenness (relief structure) such as a hologram is formed on the reflective thin film forming layer and the transparent biodegradable plastic film or sheet 1. . A hologram is a recording of interference fringes due to the interference of light between object light and reference light in an uneven relief shape. For example, laser reproduction holograms such as Fresnel holograms, white light reproduction holograms such as rainbow holograms, and more There are color holograms utilizing the above principle, computer generated holograms (CGH), holographic diffraction gratings and the like. Also, like machine readable holograms,
The reproduction light may be converted into data by the light receiving unit and transmitted as predetermined information, or authenticity determination may be performed.

In order to precisely create fine irregularities, not only optical methods, but also electron beam lithography equipment can be used to create precisely designed relief structures that produce more precise and complex reproduction light. Good. The relief shape is designed to have a pitch, depth, or specific periodic shape of the unevenness according to the wavelength (range) of the light or light source for reproducing or reproducing the hologram, the direction and the intensity of reproduction or reproduction. The pitch (period) of the unevenness depends on the reproduction or reproduction angle, but is usually 0.1 μm to several μm, and the depth of the unevenness is a factor that greatly affects the reproduction or reproduction intensity, but is usually 0.1 μm. ˜1 μm.

As in the case of a single diffraction grating, when the unevenness of exactly the same shape is repeated, as the adjacent unevenness is the same shape, the degree of interference of reflected light increases and the intensity increases, and the maximum value is reached. Converge. Diffraction in the diffraction direction is also minimized. When a single point of an image converges to a focal point, such as a stereoscopic image, the convergence accuracy to the focal point is improved, and a reproduced or reproduced image becomes clear.
Further, in the case of a transparent metal compound thin film, the upper and lower surfaces of the thin film have the same relief shape, and the more uniform the distance between the surfaces (that is, the film thickness), the higher the reproduction or reproduction strength. growing. In addition, if there are irregularities having a period and shape different from the irregularities of the hologram image on the relief surface, this becomes noise during reproduction or reproduction of the hologram or diffraction grating, which causes the image to become unclear.

  The method of shaping (also referred to as replicating) the relief shape is to use a transparent biodegradable plastic film or sheet using an original plate on which diffraction gratings and interference fringes are recorded in an uneven shape as a press die (referred to as a stamper). The concavo-convex pattern of the original plate can be replicated by superimposing the original plate on 1 and the reflective thin film 2 and heat-pressing both of them with an appropriate means such as a heating roll. The hologram pattern to be formed may be single or plural.

In order to accurately reproduce the above-mentioned extremely fine shape and to minimize distortion and deformation such as heat shrinkage after replication, the original plate is made of metal and replicated at low temperature and high pressure.
For the original plate, a metal having high hardness such as Ni is used. After a Cr or Ni thin film is formed on the surface of a glass master or the like formed by optical photography or electron beam drawing by vacuum deposition or sputtering, Ni or the like is electrodeposited (electroplating, electroless plating, Furthermore, after forming 50-1000 micrometers by composite plating etc., it can make by peeling a metal. In order to use it for high-pressure rotation type replication, it is necessary to increase the thickness accuracy of this Ni layer, and it is usually ± 10 μm, preferably ± 1 μm. For this reason, you may use the back surface grinding | polishing or the planarization method.

Since the replication method is a high pressure, a rotary method is used instead of a flat plate method, and the linear pressure is 0.1 ton / m to 10 ton / m, preferably 5 ton / m or more. If the diameter of the duplication cylinder is small, the reproducibility of the relief is lowered. Therefore, it is preferable that the duplication cylinder diameter is large. Usually, an arc having a diameter of 0.1 to 2.0 m, preferably 1.0 m or more is used. To do. A transparent biodegradable plastic film having the reflective thin film 2 or the reflective thin film 2 of the sheet 1 is pressed along the cylinder for duplication, and duplication is carried out at the above pressure by a metal cylinder from the back side. In order to minimize distortion and deformation such as thermal shrinkage after replication, the entire transparent biodegradable plastic film or sheet 1 is not heated, but only part of the reflective thin film 2 side. A heating method is desirable. Usually, it is heated to 60 ° C. to 110 ° C., preferably the melting point of the transparent biodegradable plastic film or sheet 1 to + 10 ° C. Furthermore, the precision can be further improved by keeping the metal cylinder on the back surface at room temperature or cooling it.

The plastic film or sheet 1 having a transparent biodegradability is inferior to the optical properties of the transparent film for optics used as a normal hologram substrate, so that the original plate is more relief in order to obtain excellent hologram quality. It becomes deeper and more complex, and high repeatability is required.

(Adhesive layer) As the adhesive layer 4 used in the hologram label of the present invention,
Lactone resin: ε-caprolactone, 4-methylcaprolactone, 3,5,5-trimethylcaprolactone, 3,3,5-trimethylcaprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, enanthlactone homopolymer Or a copolymer of these two or more monomers, a mixture thereof, polycaprolactone, or polybutylene succinate resin: polybutylene succinate adipate, a mixture of polybutylene succinate and polycaprolactone, polybutylene succinate And a mixture of polybutylene succinate adipate, a mixture of polybutylene succinate adipate and polylactic acid, or a mixture of polylactic acid, polylactic acid and D-lactic acid, or the like.

Or a polyester resin synthesized from a low molecular weight aliphatic dicarboxylic acid and a low molecular weight aliphatic diol, such as a combination of succinic acid and butanediol, ethylene glycol, or a combination of oxalic acid and neopentyl glycol, butanediol, ethylene glycol, etc. A mixture of modified polyvinyl alcohol, an aliphatic polyester resin and starch, a polymer obtained by adding an aliphatic isocyanate to a low molecular weight aliphatic polyester, and the like are preferable.

Natural products such as animal natural materials such as gelatin, plant natural materials such as cellulose, etc .: starch fatty acid esters, starch chitonan, cellulose, etc., as microbial production systems, polyhydroxybutyrate, polyesters: 3 as carbon source P- (3HB-CO-4HB) based on -hydroxypropionic acid, 4-hydroxybutyric acid, γ-butyrolactone, propionic acid as a carbon source, P (3HB-CO-3HV) based on valeric acid are suitable. is there. In addition, a natural rosin (gum rosin, wood rosin, tall oil rosin), rosin ester (carboxylic acid-modified rosin ester, etc.), terpene, polycaprolactone and other tackifiers are suitable for isoprene-based natural rubber.

Furthermore, rosin resin: rosin, polymerized rosin, hydrogenated rosin, rosin ester, hydrogenated rosin ester, rosin phenol resin, etc. Wood rosin, Daimalex rosin manufactured by Hercules, USA, Ester gum A, AAV, Tamanor, Harrier Star S, T manufactured by Harima Chemicals, Sumilite resin manufactured by Sumitomo Durres, terpene resin: terpene resin, terpene Phenol resin, aromatic modified terpene resin, etc. Examples include YS resin Px manufactured by Yasuhara Chemical Co., Mighty Ace G, and Piccolite A manufactured by Hercules USA.

A polyfunctional isocyanate: HMDI (hexamethylene diisocyanate) or the like may be added to these to obtain a stable adhesive force and a high adhesive force to the reflective thin film.

By making these pressure-sensitive adhesives the same system as that used for the transparent biodegradable plastic film or sheet of the present invention, even if the environment in which the hologram label is disposed of differs, The biodegradability of the two layers is the same, and a transparent biodegradable plastic film or sheet starts from its surface and cross section, and the pressure sensitive adhesive starts from the same cross section. In the case of using resin systems having different biodegradability, the biodegradation of only one layer proceeds due to the disposal environment, and there arises a problem that the reflective thin film remains in its shape.

The coating amount of the pressure-sensitive adhesive is generally about 8 to 30 g / m ² (solid content), and is applied and dried by a conventionally known method, that is, a gravure coat, roll coat, comma coat or the like. Form an adhesive. The adhesive strength of the adhesive is the peel strength between the transparent biodegradable plastic film or sheet 1 or the reflective thin film 2 and the adhesive, and in the peeling method at 180 ° in accordance with JIS Z0237, A range of about 000 g is desirable. The type and the coating amount of the pressure-sensitive adhesive as described above are such that when the pressure-sensitive adhesive is formed on the transparent biodegradable plastic film or sheet 1 or the reflective thin film 2, the peel strength is within the above range. Thus, it is preferable to select and use. In particular, in order to adjust the adhesiveness to the reflective thin film to 5,000 g to 1,000 g, it is necessary to add 0.1% to 1% of isocyanate.

  The embodiment is not limited to the above, and a hologram relief may be formed on a transparent biodegradable plastic film or sheet, and then a reflective thin film may be formed. When it is provided on the side opposite to the thin film, a protective layer made of a general resin layer may be provided in order to prevent the reflective thin film from being exposed.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, it is not limited to this. In addition, except a solvent, each composition of each layer is a mass part of solid content conversion.

  (Example 1) As a transparent biodegradable plastic film or sheet 1, a lactone-based resin (caprolactone, methylcaprolactone, propiolactone and butyrolactone copolymer, number average molecular weight 60,000: melting point 95 ° C.) thickness 40 μm is used, and an AL thin film of 50 nm is formed on this one surface using a vacuum deposition machine manufactured by ULVAC, Inc. In parallel, a Ni original plate (300 μm ± 10 μm) provided with a highly designed hologram photographed using a laser optical system and a diffraction accuracy evaluation diffraction grating (pitch 0.8 μm, depth 0.3 μm) 10 mm square Prepare a rotary relief hologram forming device (original cylinder diameter 1.0 m, original surface temperature 100 ° C., pressurized cylinder diameter 0.3 m water-cooled, pressure) by combining the AL thin film surface and the Ni original plate relief surface. The hologram and the diffraction grating were formed on the AL thin film and the transparent biodegradable plastic film or sheet 1 at 10 tons / m and a replication speed of 10 m / min.

On this AL thin film forming surface, the following composition was applied with a gravure coater so that the coating amount after drying was 20 μm, and dried at 70 ° C. to form an adhesive 4. The hologram label of Example 1 A was obtained.
・ <Adhesive composition>
Natural rubber (isopropylene) 20 parts Rosin ester 5 parts Toluene 50 parts Isopropyl alcohol 25 parts

  (Example 2) A hologram label of Example 2 was obtained in the same manner as in Example 1 except that an EBx thin film having a thickness of 200 nm was formed by using an electron beam heating type vacuum vapor deposition machine manufactured by ULVAC.

Example 3 As a transparent biodegradable plastic film or sheet 1, Tosero Palseal (polylactic acid, melting point 110 ° C.) having a thickness of 40 μm was used, and the following pressure-sensitive adhesive composition was dried with a gravure coater. The hologram label of Example 3 was obtained in the same manner as in Example 1 except that the coating amount was 20 μm and the coating was dried at 70 ° C. to form the adhesive 4.
・ <Adhesive composition>
Polylactic acid resin "Viro Ecole HYD" (manufactured by Toyobo Co., Ltd.)
39 parts Rosin ester "Superester A100" (Arakawa Chemical Co., Ltd.) 1 part Toluene 40 parts Ethyl acetate 20 parts

(Example 4) Example 3 except that the pressure-sensitive adhesive composition was as follows and the pressure-sensitive adhesive 4 was formed by coating and drying at 70 ° C. so that the coating amount after drying with a gravure coater was 20 μm. The hologram label of Example 4 was obtained by using the same method.
・ <Adhesive composition>
Polylactic acid resin "Viro Ecole HYD" (manufactured by Toyobo Co., Ltd.)
39 parts Rosin ester "Superester A100" (Arakawa Chemical Co., Ltd.) 1 part Toluene 40 parts Ethyl acetate 19.9 parts Isophorone diisocyanate 0.1 part

(Example 5) Example 3 except that the pressure-sensitive adhesive composition was as follows, and the pressure-sensitive adhesive composition was applied and dried at 70 ° C. so that the coating amount after drying with a gravure coater was 20 μm. The hologram label of Example 5 was obtained by using the same method.
・ <Adhesive composition>
Polylactic acid resin "Viro Ecole HYD" (manufactured by Toyobo Co., Ltd.)
39 parts Rosin ester "Superester A100" (Arakawa Chemical Co., Ltd.) 1 part Toluene 40 parts Ethyl acetate 19.9 parts Hexamethylene diisocyanate 0.1 part

Comparative example

(Comparative Example 1) Example 1 except that the pressure-sensitive adhesive composition was as follows, and the pressure-sensitive adhesive composition was applied and dried at 70 ° C. so that the coating amount after drying with a gravure coater was 20 μm. The hologram label of Comparative Example 1 was obtained with the same.
・ <Adhesive composition>
Vinyl acetate-acrylic copolymer 30 parts by mass Toluene 40 parts by mass Vinyl acetate 40 parts by mass

(Comparative Example 2) Example 2 except that the pressure-sensitive adhesive composition was as follows and the pressure-sensitive adhesive 4 was formed by coating and drying at 70 ° C. so that the coating amount after drying with a gravure coater was 20 μm. The hologram label of Comparative Example 2 was obtained with the same.
・ <Adhesive composition>
Vinyl acetate-acrylic copolymer 30 parts by mass Toluene 40 parts by mass Vinyl acetate 40 parts by mass

  (Comparative Example 3) Comparative Example 3 was the same as Example 3 except that a bio-degradable plastic film or sheet 1 having a biogreen (polyhydroxybutyrate) thickness of 40 μm was used. The hologram label was obtained.

(Evaluation test) The evaluation of the reproducibility of the hologram was visually determined for the design property under a halogen lamp light source. The change of the hologram was evaluated by the diffraction rate of the diffraction grating after the biodegradability evaluation. The lower the deterioration, the lower the diffraction efficiency.
Halogen lamp: Low bolt halogen lamp with 35mm diameter mirror
: Voltage 12V, luminous intensity 2300cd (candela)
Visual judgment criteria: ○ The image is clearly visible and the surrounding noise is not a concern.
: Δ The image looks clear, but I am worried about ambient noise.
: × The image is slightly blurred and the surrounding noise is conspicuous.
Diffraction efficiency measurement: Light source: Semiconductor laser: Kiko Giken MLX standard collimated laser
: Voltage DC 4.8-6.5V, beam diameter expansion 6mm at the time of parallel light
: Efficiency: reflected light intensity / incident light intensity * 100 (%)
: Criteria: × Diffraction efficiency 15% or more (deterioration has not progressed)
: △ 〃 5% ~ 15% (Deterioration is slightly advanced)
: ○ 未 満 Less than 5% (deterioration is progressing)

For evaluation of biodegradability, 5 kg of garbage was placed in an outdoor compost (capacity 100 liters), and a “100 mm square adhesive label” was placed thereon. Furthermore, 50-mm-thick garbage was put on it and left for one month, and the state of the label was visually evaluated.
Biodegradability standards: ○ Remarkably deformed and whitened, making it difficult to maintain the shape.
: Δ Deformed and whitened, but maintained the state before the test.
: X No deformation or whitening, and the state before the test is maintained.

The adhesive strength was evaluated by bonding the hologram label to a stainless steel plate with a 2 kg load rubber roll in accordance with JIS-Z0237, and after 24 hours, measuring the adhesive strength by a 180 degree peeling method at a pulling speed of 300 mm / min. The average value of the force from the time of peeling 20 mm to 80 mm after starting to peel was determined by the integration method.

(Evaluation results)
FIG. 3 shows the evaluation results.
* A transparent biodegradable plastic film or sheet 1 was used as a “transparent substrate”.
Examples 1 to 5 were excellent in biodegradability and had high hologram reproducibility.
However, in the observation from the pressure-sensitive adhesive side, in Examples 1 and 2, the biodegradability of the pressure-sensitive adhesive was slightly slower than that of the transparent substrate, and the diffraction grating still retained its shape.
In Comparative Examples 1 and 2, the pressure-sensitive adhesive is not changed at all, and the deterioration of the transparent substrate is delayed due to the influence.
In Comparative Example 3, the deterioration of the transparent base material was delayed under the present conditions for evaluating biodegradability.
In Examples 3-5, improvement of adhesive force is seen by addition of polyfunctional isocyanate.

It is sectional drawing of the hologram label which shows an example of embodiment of this invention. It is sectional drawing of the hologram label which shows another example of embodiment of this invention. It is an evaluation result of an Example and a comparative example.

Explanation of symbols

A, A 'Hologram label 1 Biodegradable plastic film or sheet 2 Reflective thin film layer 2-a Interface between thin film and plastic film or sheet 2-b Interface between thin film and adhesive 3 Biodegradable adhesive

Claims (2)

  A hologram label in which a hologram is formed on a transparent biodegradable plastic film or sheet, wherein a hologram relief is formed on one surface of the plastic film or sheet, and the hologram relief is formed on at least a part of the hologram relief. A reflective thin film is formed so as to follow the relief, and an adhesive made of a biodegradable resin on either the hologram relief or the reflective thin film or the other surface of the plastic film or sheet A hologram label in which an agent is formed.   The pressure-sensitive adhesive made of the biodegradable resin and the transparent biodegradable plastic film or sheet are made of the same resin system having biodegradability. Hologram label.

Images