JP2002160478A - Forgery preventing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forgery preventing film capable of being easily discriminated from a copied forged article, hard to wrinkle and excellent in the adhesion of printing. SOLUTION: The forgery preventing film is constituted by forming a second layer (B) containing at least two kinds of thermoplastic resins different in melt viscosity on one surface of the first layer (A) containing a thermoplastic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forgery prevention film which can be used for banknotes, bills, checks, traveler's checks, securities, cards and the like which are required to prevent forgery and tampering.

[0002]

2. Description of the Related Art In modern society, a large number of documents and cards, such as banknotes, checks, securities, and cards, which are prohibited from being forged or copied are circulated. These forgeries and copies are
What is technically impossible, rather than just prohibited by law, is needed to maintain social order. However, in recent years, with the remarkable progress of the copying technology and the copying technology, the danger of producing counterfeit products and copies is increasing year by year. In fact, counterfeit crime is increasing recently, and its technology is becoming more sophisticated.

Accordingly, various techniques for preventing forgery and duplication have been developed. For example, there is a technology that can detect forgery in appearance. Specifically, a technique for causing a fluorescent coloring substance to be present in a printed matter; a technique for printing using a magnetic ink so that a change in the density of the ink due to a magnetic action can be visually detected (Japanese Patent Laid-Open No. 5-177919).
Japanese Patent Application Laid-Open No. 60-79992; an ink having a specific reflection spectral characteristic, and a difference in reflectance of a specific value or more. A technique for printing using more than one kind of ink; a printed matter whose color changes when viewed from a certain angle (JP-A-5-177919); a printed matter provided with a watermark (latent image) -18078, and Japanese Utility Model Laid-Open No. 58-168457).

Further, there has been developed a printed material which has been modified so that characters and designs are difficult to read when copied, or a printed material in which a warning mark appears on a copy paper (Japanese Utility Model Laid-Open No. 59-64271). ). Furthermore, a printed matter printed using a special magnetic ink so that an error occurs when the copied matter is applied to the discriminator; the copied matter is printed in such a manner that the halftone dot difference of the printing of the copied matter is different from the original (genuine bill). (Japanese Patent Publication No. 56-19273 and Japanese Patent Publication No. 2-51742); a character which cannot be read by the naked eye is printed, and a hidden character can be read by a discriminator (Japanese Patent Application Laid-Open No. No. 62-130874).

[0005]

As described above, various countermeasures for preventing forgery have been developed. However, many of these originals can be duplicated in photolithography, and it is difficult to completely prevent counterfeiting. In addition, in many cases, wrinkles are generated especially when used like a genuine bill, and when it is set on a discriminator, it is determined to be "unusable" and returned. In view of these problems of the prior art, the present invention provides a forgery prevention film that can be easily distinguished from a copied counterfeit product, is less likely to wrinkle, and has excellent print adhesion. Was an issue.

[0006]

As a result of intensive studies, the present inventor has found that by forming a layer containing a thermoplastic resin having a different melt viscosity on a layer containing a thermoplastic resin, the desired effect can be obtained. The present inventors have found that a forgery prevention film showing the following can be provided, and arrived at the present invention. That is, the present invention is characterized in that a second layer (B) containing at least two kinds of thermoplastic resins having different melt viscosities is formed on one surface of a first layer (A) containing a thermoplastic resin. To provide a forgery prevention film. The difference between the melt viscosities of the two types of thermoplastic resins having different melt viscosities contained in the second layer (B) is 50 Pa
It is preferably larger than s. Further, it is preferable that a third layer (C) containing at least two kinds of thermoplastic resins having different melt viscosities is formed on the back surface of the first layer (A). The difference in melt viscosity between the two types of thermoplastic resins having different melt viscosities is preferably larger than 50 Pa · s. Further, the opacity of the forgery prevention film in the present invention is preferably 1 to 60%.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the anti-counterfeit film of the present invention will be described in detail. In this specification, “to” means a range including the numerical values described before and after it as a minimum value and a maximum value, respectively. The forgery prevention film of the present invention has a structure in which a second layer (B) is formed on a first layer (A), and a third layer is provided on a surface opposite to the first layer (A). It is preferable to have (C).
Then, each layer which comprises the forgery prevention film of this invention is demonstrated in order, and also the manufacturing method and application are demonstrated.

First layer (A) First layer (A) constituting the forgery prevention film of the present invention
Is a layer containing at least a thermoplastic resin. Examples of the thermoplastic resin used for the first layer (A) include ethylene resins such as high-density polyethylene, medium-density polyethylene, and low-density polyethylene, or propylene resins, polymethyl-1-pentene, and ethylene-cycloolefin copolymers. Polyolefin resins such as styrene-grafted polyolefin resins, polyamide resins such as nylon-6, nylon-6,6, nylon-6,10, nylon-6,12, polyethylene terephthalate and copolymers thereof,
Examples thereof include thermoplastic polyester resins such as polyethylene naphthalate and aliphatic polyester, and thermoplastic resins such as polycarbonate, atactic polystyrene, syndiotactic polystyrene, and polyphenylene sulfide. These may be used in combination of two or more. Among these, it is preferable to use a polyolefin resin. Furthermore, among polyolefin resins, propylene resins, in terms of cost, water resistance, and chemical resistance,
More preferably, high density polyethylene is used. Such propylene-based resins include isotactic or syndiotactic, propylene homopolymer (polypropylene) having various degrees of stereoregularity, propylene as a main component, ethylene, 1-butene and 1-hexene. And a copolymer with an α-olefin such as 1-heptene and 4-methyl-1-pentene can be preferably used. These copolymers have 3
It may be a ternary or quaternary system, and may be a random copolymer or a block copolymer.

In the first layer (A), in addition to the thermoplastic resin,
It is preferable to mix an inorganic fine powder and / or an organic filler. As the inorganic fine powder, those having an average particle size of usually 0.01 to 15 μm, preferably 0.01 to 8 μm, and more preferably 0.03 to 4 μm can be used. Specifically, calcium carbonate, calcined clay, silica, diatomaceous earth, talc, titanium oxide, barium sulfate, alumina and the like can be used. As the organic filler, the average particle size after dispersion is usually 0.01 to 15 μm.
m, preferably 0.01 to 8 μm, more preferably 0.1 μm.
Those having a size of 03 to 4 μm can be used. As the organic filler, it is preferable to select a resin different from the thermoplastic resin as the main component. For example, when the thermoplastic resin is a polyolefin resin, as the organic filler, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, nylon-6,
Nylon-6,6, homopolymer of cyclic olefin, copolymer of cyclic olefin and ethylene, etc., melting point of 120 ° C
~ 300 ° C or glass transition temperature 120 ° C ~ 28
It is preferable to use one at 0 ° C.

The first layer (A) may further contain, if necessary, a stabilizer, a light stabilizer, a dispersant, a lubricant, a fluorescent brightener, a coloring agent and the like. As the stabilizer, for example, a sterically hindered phenol-based, phosphorus-based, amine-based stabilizer, etc.
1% by weight can be blended. As the light stabilizer, for example, a light stabilizer such as a sterically hindered amine, a benzotriazole type or a benzophenone type may be incorporated in an amount of 0.001 to 1% by weight. As the dispersant for the inorganic fine powder, for example, 0.01 to 4% by weight of a silane coupling agent, a higher fatty acid such as oleic acid or stearic acid, metal soap, polyacrylic acid, polymethacrylic acid or a salt thereof is blended. be able to. As the fluorescent whitening agent, for example, imidazole type, imidazolone type, triazole type, thiazole type, oxazole type, oxadiazole type, coumarin type, carbostyril type, thiadiazole type, naphthalimide type, pyrazolone type, and the like, specifically, 2.5-screw [5
-T-butylbenzooxazolyl (2)] thiophene,
Dicyclohexyl phthalate, 4-methoxynaphthalic acid-N-methylimide, diaminostilbenzylsulfonic acid derivative, diaminostilbene derivative, etc.
1% by weight can be blended. As the coloring agent, 5 to 30% by weight of color pellets colored with various pigments can be blended.

The first layer (A) constituting the forgery prevention film of the present invention may have a single-layer structure or a multilayer structure of two or more layers. Further, the first layer (A) or a part of the layer constituting the first layer (A) may be stretched at least in a uniaxial direction. The first layer (A) is the layer (A)
1), a layer (A2) and a layer (A3) [A1 / A2
/ A3], the thickness of (A1 + A3) is 1 μm
As described above, the ratio of the thickness of (A1 + A3) to the thickness of A2 is 1: 4.
It is preferably 0 to 1:10. The thickness of the first layer (A) is preferably 25 to 100 μm, and 30 to 7 μm.
It is more preferably 5 μm, particularly preferably 40 to 60 μm.

Second Layer (B) and Third Layer (C) A second layer (B) is formed on one surface of the first layer (A) constituting the anti-counterfeit film of the present invention. Also, the first
It is preferable that a third layer (C) is formed on a surface opposite to the layer (A). These second layer (B) and third layer (B)
Each of the layers (C) contains a thermoplastic resin. In the forgery prevention film of the present invention, the second layer (B) contains at least two kinds of thermoplastic resins having different melt viscosities. The melt viscosity referred to in this specification is 230 ° C. and a shear rate of 122.
Melt viscosity at ^{0 s -1} . At this time, the difference between the melt viscosities of the two types of thermoplastic resins having different melt viscosities contained in the second layer (B) is preferably larger than 50 Pa · s, more preferably 70 Pa · s or more,
It is particularly preferred that it is 80 Pa · s or more. Similarly, the third layer (C) also preferably contains at least two types of thermoplastic resins having different melt viscosities, and the difference between the melt viscosities is preferably larger than 50 Pa · s,
It is more preferably 70 Pa · s or more,
It is particularly preferred that it is at least s. 5 differences in melt viscosity
When it is larger than 0 Pa · s, a streak pattern in the flow direction generated at the time of forming an extruded film can be sufficiently formed, and the streak pattern can be effectively used to prevent forgery.

The combination of the thermoplastic resins having different melt viscosities is not particularly limited, and the thermoplastic resins that can be used for the first layer (A) can be appropriately combined and used. Specifically, it is preferable to employ a combination of a propylene homopolymer and an ethylene resin, or a combination of a propylene homopolymer and a styrene-grafted polyolefin resin. The thermoplastic resin having a higher melt viscosity has a melt viscosity of 180 to 300.
Pa · s, preferably 200 to 280 Pa · s.
More preferably, s. Further, the thermoplastic resin having a lower melt viscosity preferably has a melt viscosity of 50 to 130 Pa · s, more preferably 60 to 120 Pa · s.

The second layer (B) and the third layer (C) may preferably contain an inorganic fine powder and / or an organic filler. The inorganic fine powder and organic filler used for the second layer (B) and the third layer (C) include
The same ones used for the layer (A) can be used. Further, the above-mentioned stabilizer, light stabilizer, dispersant, lubricant, fluorescent whitening agent, coloring agent and the like may be blended in the second layer (B) and the third layer (C).

The second layer (B) and the third layer (C) may each have a single-layer structure or a multi-layer structure of two or more layers. Further, the second layer (B) and the third layer (C)
Is preferably stretched at least in a uniaxial direction. The thickness of each of the second layer (B) and the third layer (C) is preferably 5 to 50 μm, and more preferably 10 to 40 μm.

The forgery prevention film of the present invention preferably has a structure in which a second layer (B) and a third layer (C) are formed on each surface of the first layer (A). In particular, the first layer (A) has a polyolefin resin content of 40 to 99.5% by weight, an inorganic fine powder and / or an organic filler 60 to
0.5% by weight, and the second layer (B) and the third layer (C) contain 25 to 100% by weight of a polyolefin resin and 75 to 0% by weight of an inorganic fine powder and / or an organic filler. Films are preferred. Further, the first layer (A) contains 50 to 97% by weight of a polyolefin-based resin, 50 to 3% by weight of an inorganic fine powder and / or an organic filler, and the second layer (B) and the third layer (C) contain a polyolefin. 30-97% by weight of resin, 70-3% by weight of inorganic fine powder
Is more preferable.

When the amount of the inorganic fine powder and / or the organic filler contained in the first layer (A) exceeds 60% by weight, the stretched resin film tends to be easily broken during the transverse stretching performed after the longitudinal stretching. Further, the second layer (B) and the third layer (C)
When the amount of the inorganic fine powder and / or the organic filler contained in the second layer (B) exceeds 75% by weight, the surface strength of the second layer (B) after the transverse stretching is low, and the second layer (B) due to mechanical shock during use or the like.
Tends to break easily.

The first layer (A) and the second layer (B), the first layer (A) and the third layer (C), the second layer (B) constituting the forgery prevention film of the present invention. ), And another layer may be provided on the third layer (C).

Production and Processing of Anti-Counterfeit Film The anti-counterfeit film of the present invention can be produced by combining various methods known to those skilled in the art. A forgery prevention film produced by any method is included in the scope of the present invention as long as it satisfies the conditions described in claim 1. As a typical production method, there can be mentioned a method in which a layer constituting the forgery prevention film is formed and then stretched. The molding method is not particularly limited, and various known methods can be used. Concretely, cast molding, calender molding, rolling molding, inflation molding, and thermoplastic resin are used to extrude a molten resin into a film using a single-layer or multilayer T-die or I-die connected to a screw type extruder. Molding can be performed by removing a solvent or oil after casting or calendering a mixture with an organic solvent or oil, molding from a solution of a thermoplastic resin and removing the solvent.

The stretching method is not particularly limited, and various known methods can be used. Specific examples of the stretching method include inter-roll stretching using a peripheral speed difference between roll groups, and clip stretching using a tenter oven. More specifically, longitudinal stretching using the peripheral speed difference of the roll group, transverse stretching using a tenter oven, rolling,
Simultaneous biaxial stretching using a combination of a tenter oven and a linear motor can be used. The stretching of each layer may be uniaxial stretching or biaxial or more stretching.
For example, when producing a film having a three-layer structure of the second layer (B) / the first layer (A) / the third layer (C), the number of stretching axes of each layer is set to uniaxial / biaxial / uniaxial, uniaxial / Any combination such as uniaxial / uniaxial, biaxial / biaxial / biaxial, etc. can be used.

The stretching ratio is not particularly limited, and is appropriately selected depending on the purpose and the characteristics of the thermoplastic resin used. For example,
When using a propylene homopolymer or a copolymer thereof as the thermoplastic resin, when uniaxially stretching, about 1.2 to
12 times is preferable, 2 to 10 times is more preferable, and when biaxial stretching is performed, the area ratio is preferably 1.5 to 60 times, preferably 1 to 60 times.
0 to 50 times is more preferable. When using other thermoplastic resins, when uniaxially stretching, it is preferably 1.2 to 10 times, more preferably 2 to 5 times, and when biaxially stretching, it is preferably 1.5 to 20 times by area magnification, preferably 4 to 20 times. -12 times is more preferable. Furthermore, heat treatment at a high temperature can be performed as necessary.

The stretching may be carried out in a suitable known temperature range from the glass transition temperature of the amorphous resin to the glass transition temperature of the amorphous portion to the melting point of the crystalline portion. it can. Generally, stretching is preferably performed at a temperature 2 to 60 ° C. lower than the melting point of the thermoplastic resin used. When a propylene homopolymer (melting point: 155 to 167 ° C.) is used as the thermoplastic resin, 152 to 16
4 ° C., 110-120 ° C. when using high-density polyethylene (melting point 121-134 ° C.), 104 when using polyethylene terephthalate (melting point 246-252 ° C.)
It is preferred to stretch at ~ 115 ° C. The stretching speed is preferably set to 20 to 350 m / min.

The order of stretching and lamination of each layer constituting the anti-counterfeit film of the present invention is not particularly limited. For example, it may be manufactured by separately stretching the first layer (A) and the second layer (B) and then laminating the layers, or may be formed by laminating the first layer (A) and the second layer (B). It may also be manufactured by stretching. When the third layer (C) is provided, the three layers may be separately stretched and then laminated, or may be laminated and then stretched collectively, or the first layer may be stretched.
After laminating and stretching the layer (A) and the third layer (C),
It may be manufactured by laminating a stretched or unstretched second layer (B). These methods can be appropriately combined. A preferred manufacturing method includes a step of laminating a plurality of layers and then stretching them together. Compared to the case of separately stretching and laminating, it is simpler and the cost is lower.

When the layer contains an inorganic fine powder and / or an organic filler, stretching causes fine cracks on the film surface and fine pores inside the film. The anti-counterfeit film of the present invention after stretching has a porosity of preferably 1 to 20%, more preferably 2 to 10%. If it exceeds 20%, the opacity tends to be too high to be unsuitable as a forgery prevention film.

The porosity is calculated by the following equation.

(Equation 1) In the formula (1), ρ ₀ represents the true density of the stretched film, and ρ represents the density of the stretched film (JIS P-8118).
Unless the material before stretching contains a lot of air,
The true density is almost equal to the density before stretching.

In order to prevent the thermoplastic resin layer constituting the outermost layer of the anti-counterfeit film of the present invention from being charged and to improve various printing suitability, it is preferable to carry out a surface treatment after the formation of the laminated structure to modify the surface. . As a method of surface treatment,
A combination of a surface oxidation treatment and a treatment with a surface treatment agent can be given. As the surface oxidation treatment, a corona discharge treatment, a flame treatment, a plasma treatment, a glow discharge treatment, an ozone treatment and the like generally used for a film can be performed alone or in combination. Among these, corona processing and frame processing are preferable. The throughput of the corona treatment is 600 to 12,000 J / m ² (10 to
200 W · min / m ² ), preferably 1,20
More preferably, it is 0 to 9,000 J / m ² (20 to 180 W · min / m ² ). For frame processing,
It is preferably 000~200,000J / m ^2, and more preferably 20,000~100,000J / m ^2.

The surface treatment agent is selected mainly from the following primers and antistatic polymers, and may be a single agent or a mixture of two or more components. From the viewpoint of improving adhesion and preventing static electricity during dry lamination,
Preferred as a surface treatment agent is a primer or a combination of a primer and an antistatic polymer.

Examples of the primer constituting the surface treating agent include polyethyleneimine, alkyl-modified polyethyleneimine having 1 to 12 carbon atoms, poly (ethyleneimine-urea), ethyleneimine adduct of polyamine polyamide, and epichlorohydrin addition of polyamine polyamide. Products, such as polyethyleneimine polymers, acrylic acid amide-acrylic acid ester copolymers, acrylic acid amide-acrylic acid ester-methacrylic acid ester copolymers, polyacrylamide derivatives, oxazoline group-containing acrylic acid ester-based polymers, Acrylic ester-based polymers such as polyacrylates, water-soluble resins such as polyvinylpyrrolidone, polyethylene glycol and polyvinyl alcohol; and polyvinyl acetate, polyurethane, ethylene-vinyl acetate Polymers, polyvinylidene chloride, chlorinated polypropylene, acrylonitrile - butadiene copolymer water-dispersible resins such as are used.

Of these, preferred are polyethyleneimine-based polymers, urethane resins and polyacrylates, more preferred are polyethyleneimine-based polymers, and further preferred are those having a degree of polymerization of from 20 to 3,000.
Or an ethyleneimine adduct of polyamine polyamide, or a modified polyethyleneimine obtained by modifying these with an alkyl halide, alkenyl halide, cycloalkyl halide or benzyl halide group having 1 to 24 carbon atoms.

Examples of the antistatic polymer constituting the surface treating agent include a cationic polymer, an anionic polymer and an amphoteric polymer. Examples of the cationic polymer include a polymer having a quaternary ammonium salt structure or a phosphonium salt structure, a nitrogen-containing acrylic polymer, and an acrylic or methacrylic polymer having nitrogen having a quaternary ammonium salt structure. Examples of the amphoteric polymer include an acrylic or methacrylic polymer having a betaine structure of nitrogen. Examples of the cationic polymer include a styrene-maleic anhydride copolymer or an alkali metal salt thereof, an alkali metal salt of an ethylene-acrylic acid copolymer or an alkali metal salt of an ethylene-methacrylic acid copolymer. Particularly preferred are acrylic or methacrylic polymers having nitrogen having a quaternary ammonium salt structure. The molecular weight of the antistatic polymer can be set to an arbitrary level depending on polymerization conditions such as polymerization temperature, type and amount of polymerization initiator, amount of solvent used, and chain transfer agent. The molecular weight of the obtained polymer is generally from 1,000 to 1,000,000, but preferably from 1,000 to 500,000.

The surface treating agent used in the present invention may contain a crosslinking agent, an alkali metal salt or an alkaline earth metal salt, if necessary. By adding a crosslinking agent to the surface treatment agent, the coating film strength and water resistance can be further improved. As a crosslinking agent, glycidyl ether,
Examples include epoxy-based compounds such as glycidyl esters, epoxy resins, and water-dispersible resins such as isocyanate-based, oxazoline-based, formalin-based, and hydrazide-based resins. The amount of the cross-linking agent to be added is usually within a range of 100 parts by weight or less based on 100 parts by weight of the active ingredient excluding the solvent of the surface modifier.

As the alkali metal salt or alkaline earth metal salt used in the surface treatment agent, water-soluble inorganic salts, for example,
Sodium carbonate, sodium bicarbonate, potassium carbonate,
Examples include sodium sulfite, other alkaline salts, and sodium chloride, sodium sulfate, sodium nitrate, sodium tripolyphosphate, sodium pyrophosphate, ammonium alum and the like. The amount of addition is usually 50 parts by weight or less based on 100 parts by weight of the active ingredient excluding the solvent of the surface modifier. Further, the surface modifier may include a surfactant, an antifoaming agent, a water-soluble or water-dispersible fine powder substance, and other auxiliaries. The amount of these optional components is usually the amount of the active component 1 excluding the solvent of the above-mentioned surface modifier.
20 parts by weight or less with respect to 00 parts by weight.

Each component of these surface treating agents can be used after being dissolved in water or a hydrophilic solvent such as methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. Above all, it is typically used in the form of an aqueous solution. The solution concentration is usually about 0.1 to 20% by weight, preferably about 0.1 to 10% by weight. Coating method is roll coater, blade coater, bar coater, air knife coater, size press coater, gravure coater,
This is performed by a reverse coater, a die coater, a lip coater, a spray coater, or the like, and if necessary, smoothing or a drying step is performed to remove excess water or a hydrophilic solvent. Coating amount is 0.00% as solid content after drying.
It is 5 to 5 g / m ² , preferably 0.01 to ² g / m ² . The timing of the surface treatment may be before or after longitudinal or transverse stretching. The surface treatment agent may be applied in one step or in multiple steps.

After performing these surface treatments, if necessary, the surface may be coated with a writability-imparting layer, a print quality improving layer, a heat transfer receiving layer, a heat-sensitive recording layer, an ink jet receiving layer, or the like. It can be provided by a method similar to the method.

A recording layer can be provided on the surface of the outermost layer of the anti-counterfeit film of the present invention thus obtained. This recording layer includes electrophotographic printing, sublimation heat transfer, melt heat transfer, direct thermal, rewritable marking, and printing using an inkjet printer, as well as letterpress printing, gravure printing, flexo printing, solvent type offset printing, and ultraviolet curing. Roll offset printing in the form of rolls can also be performed in the form of mold offset printing or film.

The anti-counterfeiting film of the present invention can be further heat-engraved to prevent forgery. If the opacity of the anti-counterfeiting film of the present invention is as low as 1 to 60%, the pressurized portion of the processed portion becomes less translucent and becomes translucent or transparent when the heat stamping is performed. Since the parts other than the pressurizing part at the time of heating and engraving remain original translucent, when watermarking is performed on a light source such as sunlight or a fluorescent lamp, a clear engraving is obtained, and it is possible to judge at a glance whether or not forgery has occurred. However, in the case of a completely transparent film, it tends to be indistinct, making it difficult to judge at first glance whether it is a forgery. In the case of an opaque film, the suitability for thermal engraving is good, but forgery using a copying machine tends to be easy. Therefore, the anti-counterfeit film of the present invention obtained by stamping a film having an opacity within the above range by heating is particularly preferable. In addition, when a large amount of inorganic fine powder and / or organic filler is contained, if engraving pressure is applied at room temperature, the voids contained in the film will be crushed and the pressurized portion will become opaque, contrary to the case of heating and engraving, and Except for the pressure part, it remains original translucent. For this reason, a clear engraving can be obtained, and it can be determined at a glance whether or not forgery has occurred. These heating or engraving at room temperature not only has the above-mentioned counterfeit prevention effect, but also enables people with vision impairment to easily determine the type of banknotes, etc. with only the sense of a fingertip. It is.

Application of the anti-counterfeiting film of the present invention The physical properties of the anti-counterfeiting film of the present invention can be appropriately adjusted according to the purpose of use, environment of use and the like. Opacity of anti-counterfeit film of the present invention (JIS P813
8) is preferably 1 to 60%, and 5 to 55%
Is more preferable, and 15 to 50% is particularly preferable. If the opacity exceeds 60%, the streak pattern formed on the second layer (B) or the third layer (C) cannot be clearly seen, and the anti-counterfeiting property tends to decrease. Further, the whiteness of the forgery prevention film of the present invention (JIS L1015)
Is preferably 60 to 100%, and 70 to 10%.
More preferably, it is 0%. If the whiteness is out of this range, characters and images printed on the surface of the anti-counterfeiting film of the present invention become unclear and difficult to identify, and
The appearance also tends to be unfavorable. Furthermore, the thickness of the anti-counterfeit film of the present invention is preferably 50 to 200 μm, more preferably 60 to 150 μm, and particularly preferably 80 to 120 μm.
If the thickness is less than 50 μm, the strength is insufficient and the durability is poor,
If it exceeds 200 μm, for example, a banknote (a banknote) tends to be too stiff and difficult to handle. These properties can be adjusted by appropriately combining known methods.

The anti-counterfeit film of the present invention has the advantage that it can be easily identified as a copy when copied, since it has been subjected to anti-counterfeit processing. For example, when a genuine bill prepared using the anti-counterfeit film of the present invention is copied using an OHP sheet made of silver halide photographic paper, thermal transfer image receiving paper, polyethylene terephthalate biaxially stretched film, or the like, When the copy holding cover is made of an aluminum plate, the translucent portion of the genuine bill is printed in black and white in a copy. Therefore, by comparing the genuine bill and the translucent portion of the copy visually, the two can be easily distinguished. Also, the copy press lid of the copier is a white plastic plate,
In the case of cloth or white cardboard, the streak pattern in the watermark portion of the genuine bill becomes the paper color only on the copy paper and disappears, and becomes transparent and disappears on the copied OHP film. . For this reason, if the presence or absence of a streak pattern is confirmed by visually comparing the genuine bill and the watermark portion of the copy, the two can be easily distinguished.

In order to ensure that the anti-counterfeiting film of the present invention exerts the anti-counterfeiting effect, it is necessary to intentionally provide a portion (watermark portion) on which the recording layer or the like is not printed. preferable.

The anti-counterfeit film of the present invention can be widely applied to films requiring anti-counterfeiting. For example, banknotes, bills, checks, travelers checks,
Lotteries, gift certificates, stock certificates, other securities, various cards, admission tickets, tickets, ID cards, driver's licenses, resident certificates,
Family register, seal certificate, passport, visa, deposit certificate,
It can be applied to pledge setting documents. In particular, when a banknote is manufactured using the forgery prevention film of the present invention,
The appearance looks just like a conventional banknote, and does not give a sense of incongruity.
In addition, it has excellent water resistance and durability, and can be used in various applications.

[0041]

The features of the present invention will be described more specifically with reference to the following examples. Material, amount used in the following examples,
The ratio, processing content, processing procedure, and the like can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples described below.

Example 1 Melt flow rate (MF)
R) 3 parts by weight of heavy calcium carbonate having an average particle size of 3 μm with respect to 87 parts by weight of a propylene homopolymer of 4 g / 10 minutes;
3-methyl-2,6-di-t- is based on 10 parts by weight of high-density polyethylene having an MFR of 10 g / 10 min and 100 parts by weight of a total amount of propylene homopolymer and heavy calcium carbonate.
0.05 parts by weight of butylphenol and a phenolic stabilizer (Irganox 1010, manufactured by Ciba-Gaiky)
0.08 parts by weight and 0.05 parts by weight of a phosphorus-based stabilizer (trade name: Weston 618, manufactured by GE Plastics Co., Ltd.) were blended to obtain a composition (A). 250 ° C. of composition (A)
And extruded from a T-die connected to an extruder set at 230 ° C. to obtain a non-stretched film. This film was heated to 155 ° C. and stretched 4.6 times in the machine direction with a machine for stretching composed of rolls having different peripheral speeds to obtain a stretched film.

50 parts by weight of a propylene homopolymer (B1) having a melt viscosity of 200 Pa · s and 50 parts by weight of a metallocene polyethylene (B2) having a melt viscosity of 100 Pa · s were mixed with 240 parts by weight.
The mixture was melt-kneaded in an extruder set at a temperature of ° C. This melt viscosity difference 1
The composition (B) of 00 Pa · s was extruded on both sides of the stretched film of the composition (A) obtained above to obtain a three-layer laminate (B / A / B). The thermoplastic resin had a melt viscosity of 230 ° C. and a shear rate of 1220S-1 and was manufactured by Toyo Seiki Co., Ltd. Capillograph 1C (cylinder diameter 9.55 m).
m, L / D = 10).

The obtained three-layer laminate was heated at 160 ° C. in a tenter oven and stretched 9 times in the transverse direction. Then, it passed through a heat set zone (set temperature: 165 ° C.) following the tenter oven. Corona discharge treatment was performed on both surfaces of the film at an applied energy density of 90 W · min / m ² , and butyl-modified polyethyleneimine, an ethyleneimine adduct of polyamine polyamide, and acrylic acid having a quaternary ammonium salt structure were formed on both surfaces. Using a roll coater, an aqueous solution containing an equal mixture of alkyl ester-based polymers is coated at a coating amount of about 0.1 g / m per side after drying.
^It was coated so as to be ² and dried. The thickness (B / A / B) of each layer of the obtained three-layer laminated film was 20 μm / 50
μm / 20 μm. The obtained forgery prevention film had a transparent streak pattern in the flow direction used for forgery prevention. The opacity, whiteness, and porosity of the forgery prevention film were as shown in Table 1.

On both sides of the obtained film, offset printing inks POP and K ink of Dainippon Ink and Chemicals,
The pattern was printed using POP / K indigo, POP / K red, and POP / K yellow. At this time, 20 mm
The unprinted part of the circle was left. Using a color copying machine (Fuji Xerox Co., Ltd., Docu Color 1250)
The above forgery prevention film was color-copied as copy base paper. As an object to be copied, pulp paper and an OHP film made of a polyethylene terephthalate biaxially stretched film were used, and it was evaluated whether or not whitening stripes at the watermark portion were copied according to the following criteria. The results are shown in Table 1. ：: Undefined whitening stripes at the watermark portion are not copied. When pulp paper is used for the subject, the watermark part remains white,
In the case of an OHP film, the watermark portion remains transparent. X: The irregular whitening stripe at the watermark portion is copied.

Further, an attempt was made to copy to a copy base paper by a color copying machine using the forgery prevention film as a copy subject. As a result, it was confirmed that it was difficult to pass the forgery prevention film (paper cannot be passed) due to the heat of the transfer roll, and color copying was not possible.

Example 2 230 ° C., shear rate 122
50 parts by weight of a propylene homopolymer (B1) having a melt viscosity of 200 Pa · s at 0S-1 and 50 styrene-grafted polyethylene (B2) having a melt viscosity of 100 Pa · s at 230 ° C. and a shear rate of 1220 S ^−1. Parts by weight were melt-kneaded with an extruder set at 240 ° C. The composition (B) having a melt viscosity difference of 100 Pa · s was extruded by an extruder, and laminated on both sides of a stretched film of the composition (A) obtained in the same manner as in Example 1, to form a three-layer laminate (B
/ A / B). Hereinafter, the same operation as in Example 1 is performed,
The thickness (B / A / B) of each layer is 23 μm / 50 μm / 23
μm) was obtained. The obtained forgery prevention film had a stripe pattern in the flow direction used for forgery prevention. The opacity, whiteness, and porosity of the forgery prevention film were as shown in Table 1.

Table 1 shows the results of the same anti-counterfeiting evaluation as in Example 1. In addition, an attempt was made to copy the image onto copy base paper by a color copier using the forgery prevention film as a copy subject. As a result, due to the heat of the transfer roll, it is difficult to pass the anti-counterfeit film (paper cannot be passed),
It was determined that color copying was not possible.

[0049]

[Table 1]

[0050]

As is clear from Table 1, when the anti-counterfeiting film of the present invention is copied, the brightness of the identification pattern changes, so that the copy and the genuine one can be easily distinguished. Further, the anti-counterfeiting film of the present invention is less likely to wrinkle, and is excellent in printability and watermark, so that it can be suitably used for banknotes, securities, secret documents, and the like.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takahiko Ueda 23rd Towada, Kamisu-cho, Kashima-gun, Ibaraki Prefecture F-term in Yupo Corporation Kashima Plant (reference) AA08 AK01A AK01B AK01C AK05 AK07 AK25 AK46 AK63 AL05B BA02 BA03 BA06 BA07 BA10A BA10B BA10C BA15 GB90 JA06B JA06C JB16A JB16B JB16C JN08 YY00B YY00C

Claims (5)

[Claims] 1. A second layer (B) containing at least two kinds of thermoplastic resins having different melt viscosities is formed on one surface of a first layer (A) containing a thermoplastic resin. Anti-counterfeiting film. 2. The difference between the melt viscosities of two thermoplastic resins having different melt viscosities contained in the second layer (B) is 50 Pa.
The film for preventing forgery according to claim 1, wherein the film is larger than s. 3. A third resin containing at least two kinds of thermoplastic resins having different melt viscosities on the back surface of the first layer (A).
The anti-counterfeit film according to claim 1 or 2, wherein the layer (C) is formed. 4. The difference in melt viscosity between two thermoplastic resins having different melt viscosities contained in the third layer (C) is 50 Pa.
The film for preventing forgery according to claim 3, wherein the film is larger than s. 5. The forgery prevention film according to claim 1, wherein the opacity is 1 to 60%.