JPH11277867A - Forgery preventing paper thread and forgery preventing paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture stably a forgery preventing paper containing threads contained among paper layers to be contained therein during the manufacture without thread surface printing scummings generated by printing. SOLUTION: Forgery preventing paper threads are provided with thermoplastic bonding agent layers on both faces of a thread-shaped or tape-shaped base, and a surface bonding agent layer is composed of thermoplastic resin having the 60 deg. contact angle formed on the side of visible threads to water at the time of 15 seconds after dropping or larger and the 20 deg.C glass transition temperature or higher. Also the surface bonding agent layers of the forgery preventing paper threads are composed of thermoplastic resin dissolved in an organic solvent or in a soap-free emulsion. The forgery preventing paper contains forgery preventing paper threads among paper layers to be contained therein during the manufacture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread for forgery prevention paper and a forgery prevention paper. More specifically, the present invention relates to an anti-counterfeit paper in which the drawbacks of the conventional thread are improved, and the anti-counterfeit paper thread has no printing stain on the surface of the anti-counterfeit paper thread when printing the anti-counterfeit paper.

[0002]

2. Description of the Related Art In recent years, advances in copier technology have facilitated the forgery of securities and have become a major social problem. Banknotes, gift certificates, checks, stock certificates, passports, identification cards, cards, etc. Various forgery prevention measures have been taken to prevent unauthorized alteration and forgery.

As a countermeasure for preventing forgery, JP-A-48-75
No. 808, JP-B-52-48660, JP-A-51-1
For example, there is a forgery prevention paper referred to as a so-called threaded paper in which a thread (referred to as a thread) is formed between paper layers described in Japanese Patent No. 30308 or the like.

[0004] The form of the thread to be formed between the paper layers is generally about 10 to 100 µm in thickness and 0.2 to 30 mm.
It is in the form of a thread or tape having a width of about one, and a metal-deposited film is generally used. In recent years, holograms, pixelgrams, grating images, etc., which are extremely difficult to duplicate, have been affixed to credit cards, banknotes, etc. to prevent counterfeiting by advanced copier technology. Also used as a thread. The anti-counterfeit paper incorporating these threads cannot be forged in the metallic luster portion of the threads even when copied with a copying machine, and is difficult to falsify.

Further, it is necessary to firmly adhere the thread and the laid-in paper layer in order to prevent the thread which has been laid between the paper layers from falling off. Therefore, it is preferable to apply an adhesive to the front and back of the thread and adhere the paper to both sides.

However, when printing anti-counterfeit paper into which a thread is formed, the adhesive applied to the visible side of the thread must be applied to a printing machine such as a blanket roll because of the necessity of firmly adhering the paper layer and the thread. It may come into contact with the ink on the roll, transfer the ink to the adhesive, and stain the thread surface.

[0007]

SUMMARY OF THE INVENTION The present invention relates to anti-counterfeit paper which can be manufactured stably without printing stains on the thread surface due to printing processing in anti-counterfeit paper in which threads are laid between paper layers.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on an adhesive applied to a thread used in the manufacture of anti-counterfeit paper, and as a result, have found that the adhesive strength between the thread and the paper layer is excellent and the thread surface is excellent. Have found a configuration of an adhesive layer that can achieve both the property of preventing printing stains due to ink adhesion during printing of forgery prevention paper, and have completed the present invention.

That is, in the present invention, in a thread in which a thermoplastic resin adhesive layer is provided on both surfaces of a thread-like or tape-like substrate, the surface adhesive layer provided on the visible side of the thread has a dripping 15. It is characterized by being composed of a thermoplastic resin having a contact angle with water after 60 seconds of 60 degrees or more and a glass transition temperature of 20 degrees C or more.

Further, the present invention is a thread comprising a thread surface adhesive layer dissolved in an organic solvent or made of a thermoplastic resin which is a soap-free emulsion. Furthermore, the present invention is a forgery prevention paper characterized in that the above-mentioned thread is formed between paper layers.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The anti-counterfeit paper thread of the present invention is obtained by applying an adhesive made of a thermoplastic resin to both front and back surfaces of a substrate and drying. Further, the thread-containing forgery prevention paper of the present invention is provided with a thermoplastic adhesive layer in advance on both sides of a thread-like or tape-like base material before performing at least the final lamination with a multilayer paper machine. The thread is inserted between the paper layers while being unwound in a laminating step of a paper machine, and the adhesive layer of the thread is plasticized by the heat of the drying step and adhered to the paper layer.

Since the anti-counterfeit paper is printed by various printing machines and finished as a product, it is necessary that the thread surface is not stained with ink adhering to a printing machine roll or the like. The measurement of the contact angle in the present invention is described in the section of Examples.

In order to prevent printing stains, the adhesive (hereinafter simply referred to as “adhesive”) on the visible side of the thread used in the present invention has a contact angle to water of 60 seconds after dropping for 60 seconds.
It is preferably an adhesive having a glass transition temperature of 20 ° C. or higher and dissolved in an organic solvent, or an adhesive comprising a soap-free emulsion. The reason that the thread surface is stained during printing is that low-molecular monomers and surfactants remaining on the thread surface after drying the adhesive that has flowed out into the soaking water used during printing increase the affinity with the printing ink. When the contact angle of the thread surface adhesive with water is 60 degrees or more, the area of contact with water by immersion on the adhesive becomes small, and as a result, printing stains can be reduced. A surfactant-containing emulsion type or a water-soluble type is difficult to use because it uses a fountain solution used at the time of printing as a medium and easily causes printing stains. Further, when the glass transition temperature of the thread surface adhesive is less than 20 ° C., the problem that the dryer of the paper machine is contaminated with the hot-melt adhesive during the production of the anti-counterfeit paper tends to occur, which makes the use difficult. .

The glass transition temperature can be determined experimentally by DSC (differential scanning calorimeter).
Further, it can also be determined by the following Fox formula: 1 / Tgm = Σwi / Tgi Tgm: glass transition temperature of the composite component, wi: weight fraction of each component, and Tgi: glass transition temperature of each component.

The resin of the adhesive used in the present invention is dripping 1
The contact angle with water after 5 seconds is not less than 60 degrees and the glass transition temperature is not less than 20 ° C., but is not particularly limited, but may be acrylic resin, styrene butadiene resin, styrene-isoprene resin, polyester resin, ethylene resin. Known vinyl acetate resins, vinyl acetate-vinyl alcohol resins and the like, which can be generally used as a heat seal adhesive,
Although it is a publicly used resin composition, an ethylene-vinyl acetate resin, a polyester resin, a vinyl chloride-vinyl acetate resin, an olefin resin, an acrylic resin, or an acryl-styrene resin is particularly preferably used.

These resins may be used as an adhesive as they are, or a plurality of resins may be mixed and used.
If necessary, the surface activity of various known dyes and pigments, antifoaming agents, wetting agents, etc., as long as the contact angle to water after 15 seconds of dropping is 60 ° or more and the glass transition temperature can be maintained at 20 ° C. or more. Auxiliary agents such as agents, anti-blocking agents, lubricants and thickeners may be added.

The method of applying the adhesive is performed by various coating apparatuses such as brush coating, spray coating, a roll coater, a Meyer bar coater, a gravure roll coater, a blade coater, and an air knife coater. Done in a conventional manner. In addition,
The coating amount is preferably about 0.5 to 15 g / m ² in terms of dry weight. However, if it is less than this, sufficient adhesive strength cannot be obtained, and if it is too large, saturation of the adhesive function or excessive drying is required, which is not economically preferable.

The thread substrate used in the present invention is not particularly limited, but has a thickness of 10 to 100 μm which is thin and excellent in strength.
In general, PET films of about m are often used. PE
The T film is subjected to metal deposition, printing of characters and patterns, optical special processing such as holograms and grating images, etc. for the purpose of preventing forgery and decorative purposes, and providing information by providing a magnetic recording layer. You can also. In addition,
The thread substrate is coated with an adhesive, dried, slit into a predetermined width, and used as a thread.

The thread thus obtained is inserted between the paper layers in a laminating step of a known multi-layer paper machine in which various wire parts are combined, and if necessary, various surface sizes and the like are pressed in the middle of the paper making. It is coated with a device or the like and dried with a drier to obtain the desired anti-counterfeit paper. Further, the obtained anti-counterfeit paper may be subjected to a machine calendar or a super calender treatment, or a pigment coating layer, a heat-sensitive recording layer, a thermal transfer image receiving layer, etc. may be provided on the surface by various coating apparatuses.

The anti-counterfeit paper obtained by the present invention is usually further subjected to desired printing and cutting, and is provided with a banknote, a gift certificate, a magnetic recording layer, and used as a ticket or a prepaid card.

[0021]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which, of course, are not intended to limit the present invention.

Example 1 [Preparation of Thread] As a base material, a 12 μm-thick aluminum-evaporated PET film (trade name “G1302E-12” manufactured by Diafoil Hoechst Co., Ltd.) was viewed from the PET film side (this surface was visually recognized). The same applies to the following.)
An ethylene-vinyl acetate organic solvent solution adhesive having a glass transition temperature of about 30 ° C. (trade name “AD-1790-15” manufactured by Toyo Morton Co., Ltd., solvent: toluene) is adjusted to have a dry weight of 1.0 g / m ^2. Was coated with a gravure roll coater and dried. Drop of the obtained surface adhesive layer 15
The contact angle with water after 10 seconds was 105.1 degrees.

Next, a glass transition temperature of about 3
A 2 ° C. polyester-based aqueous solution type adhesive (trade name “Plus Coat RZ-648” manufactured by Taiyo Chemical Industry Co., Ltd.) was applied with a gravure roll coater to a dry weight of 3.0 g / m ² and dried. . Then, after slitting to a width of 1 mm with a microslitter, it was wound around a bobbin to obtain a thread.

[Manufacture of anti-counterfeit paper] A 1 cm × 1 cm tape is placed at intervals of 1 cm on the same circumferential surface of the mesh cylinder of the first tank of a mesh paper machine having two tank bats. The mesh was adhered to close the mesh, and a paper layer having a hole of 1 cm × 1 cm every 1 cm was formed as a first paper layer. The second cylinder net cylinder was not worked, and a plain second paper layer was formed.
In addition, the thread unwinding device is installed between the mesh cylinders of the first tank and the second tank, and in a position where the thread overlaps the hole of the first paper layer, the second paper layer and the aluminum deposition surface side are in contact with each other. Made to be inserted. The wet paper (water content: about 50%) produced by this paper machine is dried by 12 cylinder dryers (surface temperature: about 70 to 100 ° C.) and then machine-calendered. Using the thread produced by the above paper machine, a type of anti-counterfeit paper in which the thread was repeatedly exposed and buried on one side was obtained.

Example 2 A vinyl chloride-vinyl acetate organic solvent solution adhesive having a glass transition temperature of about 66 ° C. (trade name “SE-600” manufactured by Siden Chemical Co., Ltd.) was placed on the PET film side of the aluminum-deposited PET film. (Solvent: ethyl acetate) in a dry weight of 1.5
A forgery prevention paper was obtained in exactly the same manner as in Example 1 except that a thread was obtained by coating and drying to give g / m ² . In addition, the contact angle with respect to water 15 seconds after dripping of the obtained surface adhesive layer was 67.8 degrees.

Example 3 An acrylic soap-free type emulsion adhesive having a glass transition temperature of about 40 ° C. (trade name “GD-902”, manufactured by NSC Japan) was placed on the PET film side of an aluminum-deposited PET film by dry weight. An anti-counterfeit paper was obtained in exactly the same manner as in Example 1, except that a thread was obtained by applying and drying at 1.5 g / m ² . The contact angle with water 15 seconds after the drop of the obtained surface adhesive layer was 62.5 degrees.

Comparative Example 1 An acrylic emulsion adhesive having a glass transition temperature of about 35 ° C. (trade name “Nipol LX855” manufactured by Zeon Corporation) having a dry weight of 2 g / m 2 was applied on the PET film side of an aluminum-deposited PET film. ^A forgery prevention paper was obtained in exactly the same manner as in Example 1 except that a thread was obtained by coating and drying to obtain No. 2. In addition, the contact angle with respect to water 15 seconds after dripping of the obtained surface adhesive layer was 18.4 degrees.

COMPARATIVE EXAMPLE 2 A 12 μm thick aluminum-evaporated PET film (trade name “G1302E-12” manufactured by Diafoil Hoechst Co., Ltd.) was used as a substrate. Solvent solution type adhesive (trade name “PES-370” manufactured by Toa Gosei Co., Ltd., solvent: ethyl acetate / acetone) was applied to a dry weight of 1.5 g / m ² and dried to obtain a thread. In the same manner as in Example 1, anti-counterfeit paper was obtained. In addition, the contact angle with respect to water 15 seconds after dropping of the obtained surface adhesive layer was 48.7 degrees.

Comparative Example 3 As a substrate, a 12 μm-thick aluminum-evaporated PET film (trade name “G1302E-12” manufactured by Diafoil Hoechst Co., Ltd.) was coated on the polyester film side with a polyester organic material having a glass transition temperature of about 11 ° C. Solvent solution adhesive (trade name "SK Dyne 5273" manufactured by Toagosei Co., Ltd., solvent:
1.5 parts by weight of toluene / ethyl acetate / acetone)
g / m ^2, and a forgery prevention paper was obtained in the same manner as in Example 1 except that a thread was obtained by drying and coating. In addition, the contact angle with respect to water 15 seconds after dropping of the obtained surface adhesive layer was 84.9 degrees.

[Evaluation] The thread surface printing stains generated during printing on each forgery prevention paper were evaluated by the following method.
The results are shown in Table 1.

[Contact angle] P of aluminum evaporated PET film
5 μl of water was dropped on the adhesive-coated surface provided on the ET film side, and the contact angle was measured after 15 seconds. (Measurement device: Kyowa Interface Science Co., Ltd., CA-X type contact angle meter)

[Print Smear] Each obtained forgery prevention paper was
Printing was carried out using 000 mUV ink, and the stain state of the surface thread was judged by visual evaluation according to the following criteria. A: There is no print stain. ；: Slight printing stains are generated by long-time processing. Δ: No print stains occur at the beginning of printing, but print stains occur after a long processing. X: The printing stain is severe and not suitable for processing.

[Dryer Soil] Each of the obtained anti-counterfeit paper threads was milled by 1000 m, and the stain condition of the cylinder dryer of the machine coater was judged by visual evaluation according to the following criteria. A: The dryer is not dirty at all. ；: Dryer dirt is slightly generated by long-time milling, but does not affect processing. △: Dryer contamination does not occur in the initial stage of making,
Drying for a long time causes stains on the dryer. ×: Stain of the dryer was severe and not suitable for processing.

[0034]

[Table 1]

[0035]

As is clear from the results shown in Table 1, the present invention is an excellent anti-counterfeit paper thread without printing stains, and an anti-counterfeit paper in which the anti-counterfeit paper thread is laid between paper layers. .

Claims (3)

[Claims] In a thread having a thermoplastic resin adhesive layer provided on both sides of a thread-like or tape-like base material, the surface adhesive layer provided on the visible side of the thread has a water content of 15 seconds after dripping. A thread for forgery prevention paper, comprising a thermoplastic resin having a contact angle of 60 ° or more with a glass transition temperature of 20 ° C. or more. 2. The anti-counterfeit paper thread according to claim 1, wherein said surface adhesive layer is made of a thermoplastic resin dissolved in an organic solvent or a soap-free emulsion. 3. An anti-counterfeit paper characterized in that the anti-counterfeit paper thread according to claim 1 or 2 is laid between paper layers.