JPH10292297A - Thread-containing paper for preventing counterfeit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thread-containing paper for preventing counterfeit useful for bill, etc., excellent in printability, hardly curling, by making a water elongation in the width direction a fixed value or smaller than it. SOLUTION: In this paper for preventing counterfeit obtained by adding a thread prepared by providing one side or both sides of a filamentous or a taped substrate with a thermoplastic and/or a water remoistening adhesive layer to a paper layer and making a paper, the water elongation in the width direction of the paper for preventing counterfeit is <=4.3%. Preferably the substrate is a polyethylene terephthalate film having about 10-100 μm thickness and excellent in strength in spite of thinness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thread-prevention forgery-prevention sheet.

[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. For example, gold thread, silver thread, plastic film, metal-deposited film and the like are used. In recent years, holograms, pixelgrams, grating images, etc., which are extremely difficult to duplicate, are affixed to credit cards, banknotes, etc. to prevent counterfeiting by advanced copier technology, but these are also used as threads . 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.

[0005] However, threaded forgery prevention paper has the drawback that it is more susceptible to twisting and curling due to changes in humidity than ordinary paper, and is more likely to cause trouble on a printing machine when performing multicolor printing.

[0006]

SUMMARY OF THE INVENTION The present invention relates to anti-counterfeit paper having excellent printability with almost no curl, which is a cause of trouble in printing thread-containing anti-counterfeit paper.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies on the relationship between the occurrence of torsional curl due to humidity change and the like of thread-containing forgery prevention paper and various paper quality data, and as a result, the degree of infiltration expansion and contraction was specified. It has been found that when the value is smaller than the value, the generation of torsional curl is remarkably suppressed, and the present invention has been completed.

[0008] That is, the present invention relates to a forgery prevention paper in which a thread in which a thermoplastic and / or water-rewetting adhesive layer is provided on one or both sides of a thread-like or tape-like base material is formed in a paper layer. And a thread-equipped forgery-preventing paper, characterized in that the forgery-preventing paper has a degree of infiltration and contraction in the width direction of 4.3% or less.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The anti-counterfeit paper of the present invention is prepared by applying an adhesive to a substrate surface in advance and drying the thread so that the thread does not easily come off or fall off.
It is obtained by inserting between paper layers and drying in the laminating step of a paper machine. The anti-counterfeit paper thus obtained is usually further subjected to desired printing and cutting, etc., and banknotes, gift certificates,
A magnetic recording layer is provided and used for tickets and prepaid cards.

Generally, multi-color printing is performed for anti-counterfeiting printing. However, when curling occurs, troubles such as jamming frequently occur on a printing press, making it difficult to stably operate continuously. If the curl generated at the time of printing is a normal convex curl or concave curl, trouble on the printing press can be prevented beforehand by intentionally aligning the curl directions. However, in the case of twisted curl, trouble tends to occur regardless of the direction of curl.

Not all the causes of the occurrence of torsional curl have been elucidated. Generally, the orientation of pulp fibers during papermaking has a certain angle with respect to the flow direction of the paper, or the drying step. It is said that twist curl occurs when a difference in drying speed occurs in the width direction of the paper. The reason why twist curl is particularly likely to occur in thread-containing forgery prevention paper is not necessarily clear, but is presumed as follows.

That is, forgery-prevention paper containing threads is papered with a number of threads adhered between paper layers in a specific width, and each thread undergoes heat shrinkage in a drying process of the paper machine, and Strain between the thread and the distant part due to pulling the wet paper layer in the vicinity,
The paper layer is dried as it is to fix the distortion. It is considered that the distortion fixed inside the paper is partially released when the paper expands and contracts due to a change in humidity or the like, and causes torsional curl. Therefore, the wider the thread width and the stronger the pulling force of the paper layer, the more the distortion is likely to occur, and as a result, the curl is likely to occur.

In order to prevent twisting and curling, it is necessary not to cause distortion inside the paper or to expand or contract the paper due to changes in humidity or the like. It is difficult technically.

The present invention minimizes the expansion and contraction of the paper, which causes twisting curl, by suppressing the infiltration expansion and contraction of the forgery prevention paper to a specific range and making the forgery prevention paper extremely excellent in dimensional stability. Things. That is, the anti-counterfeit paper of the present invention has a degree of infiltration elasticity of 4.3% measured by the following method.
Or less, preferably 3.8% or less.

The immersion elasticity applied to the present invention is a value obtained by measuring the elongation in the width direction of the paper when the sample is immersed in water for 5 minutes using a Fenchel immersion elasticity tester. .

Incidentally, the degree of water penetration and expansion is 3.8% to 4.3%.
When the forgery prevention paper suddenly expands and contracts in the range of%, twist curl may occur. When the forgery prevention paper is 4.3% or more, twist curl is likely to occur, and it becomes difficult to continuously print the forgery prevention paper stably.

It is important to minimize the distortion fixed inside the paper in order to prevent twist curl, and the width of the thread used for the forgery prevention paper of the present invention is 2.5 mm or less. Is preferred.

Incidentally, the multi-layered paper is usually produced by a round paper machine. In this case, the degree of immersion expansion is about 5%, and the immersion expansion degree of the present invention as in the present invention is obtained by a general paper machine. It is difficult to make small papers. However, the manufacture of the anti-counterfeit paper of the present invention becomes relatively easy by combining a Yankee dryer in the drying step of the paper machine and precisely controlling the drying conditions (canvas holding pressure, dryer temperature gradient) and the like.

The type of the thread adhesive used in the present invention is not particularly limited, and may be an acrylic resin, a styrene-butadiene resin, a styrene-isoprene resin, a polyester resin, an ethylene-vinyl acetate resin, a vinyl acetate resin.
Known and publicly used resin compositions which can be generally used as a heat seal adhesive or a water rewetting adhesive, such as a vinyl alcohol-based resin, are used.

These resins may be used as an adhesive as they are, or a plurality of resins may be mixed and used.
If necessary, various known dyes and pigments, surfactants such as defoamers and wetting agents, and auxiliaries such as antiblocking agents, lubricants and thickeners may be added.

The adhesive can be applied 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 amount of coating is preferably about 1 to 15 g / m ² in terms of dry weight.

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, pixelgrams, grating images, etc., for the purpose of preventing forgery and decorative purposes. It can also be provided. The thread base material is coated with an adhesive, dried, slit into a predetermined width, and used as a thread.

The thread obtained in this way is inserted between 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 sizing agents and the like are sized during the paper making. It is coated with a press or the like and dried with a drier to obtain the desired anti-counterfeit paper. The application of the surface sizing agent or the like may be performed by installing a size press device or the like between the dryers during drying, or may be performed after the coating is completely dried, and then dried again. 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.

[0024]

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.

[Preparation of thread A]
2 μm aluminum evaporated PET film (trade name “G130
2E-12 "Diafoil Hoechst Co., Ltd.) on the aluminum deposition side with a polyester adhesive (trade name" PES-
370S30 "manufactured by Toagosei Chemical Industry Co., Ltd.) 6g / m ² on a dry weight, PET surface side to the SBR-based adhesive (trade name" SN337 "Sumitomo Chemical Eibiesu Latex Co., Ltd.) by dry weight 4g / m ² Was applied with a gravure roll coater and dried. Then, after slitting to a width of 1.0 mm with a microslitter, it was wound around a bobbin to obtain a thread A.

[Preparation of thread B]
2 μm aluminum evaporated PET film (trade name “G130
Ethylene-vinyl acetate adhesive (trade name "SUMICA FLEX 301" manufactured by Sumitomo Chemical Co., Ltd.)
Is applied with a gravure roll coater to a dry weight of 9 g / m ² and an acrylic adhesive (trade name “Nipol LX814” manufactured by Nippon Zeon Co., Ltd.) on the PET side to a dry weight of 2 g / m ^2. Was. Then, after slitting to a width of 2.0 mm with a microslitter, it was wound around a bobbin to obtain a thread B.

[Manufacture of anti-counterfeit paper] Example 1 On a circular cylinder paper machine provided with two cylinder bats, 1 cm was previously placed on the same circumferential surface of the circular cylinder of the first tank.
× 1cm form of tape was attached at 1cm intervals keep blocking the mesh, to form a paper layer with a hole vacant 1cm × 1cm 1cm of every as a first paper layer (Kazeinuimaitsubo 35 g / m ²⁾ I made it. The second cylinder net cylinder was not modified, and a plain second paper layer (air-dried rice tsubo 70 g / m ² ) was formed. Further, the thread unwinding device is installed between the cylinders of the first tank and the second tank, and the thread is inserted in a position where the thread overlaps the hole of the first paper layer so that the second paper layer and the aluminum deposition surface side are in contact with each other. I made it. The wet paper (moisture about 50%) made by this paper machine is composed of a Yankee dryer (surface temperature of 88 ° C.) in contact with the first paper layer, followed by six cylinder dryers (surface temperature of about 60 ° C. to 70 ° C.). After drying with, machine calendering is performed. By the above paper machine,
Using the thread A, forgery prevention paper of a type in which the thread was repeatedly exposed and buried on one side was obtained. The anti-counterfeit paper obtained had a degree of water penetration and expansion of 2.7%.

Example 2 In the same manner as in Example 1, the temperature of the Yankee dryer was reduced to 80 ° C., and the temperature of the cylinder dryer was reduced to 60-8.
By raising the temperature to 0 ° C., anti-counterfeit paper having a water immersion elasticity of 3.3% was obtained.

Example 3 In the same manner as in Example 1, the temperature of the Yankee dryer was lowered to 73 ° C., and the temperature of the cylinder dryer was reduced to 60 to 1 °.
The temperature was raised to 00 ° C. to obtain anti-counterfeit paper having a degree of immersion stretching of 4.1%.

Example 4 Using a thread B in place of the thread A, in the same manner as in Example 1, anti-counterfeit paper having an infiltration elasticity of 2.7% was obtained.

Example 5 A forgery-preventing sheet having a degree of immersion elasticity of 3.3% was obtained in the same manner as in Example 2, except that the thread B was used instead of the thread A.

Example 6 Forgery-preventing paper having a degree of immersion elasticity of 4.1% was obtained in the same manner as in Example 3 except that thread B was used instead of thread A.

Comparative Example 1 In the same manner as in Example 1, the temperature of the Yankee dryer was reduced to 62 ° C., and the temperature of the cylinder dryer was reduced to 60 to 1 °.
By raising the temperature by 20 ° C., anti-counterfeit paper having an infiltration elasticity of 4.6% was obtained.

Comparative Example 2 An anti-counterfeit paper was obtained in the same manner as in Example 1 except that the surface temperature of 14 cylinder dryers was dried at 60 to 110 ° C. without using a Yankee dryer.
In addition, the degree of immersion expansion and contraction of the obtained forgery prevention paper was 5.5%.

Comparative Example 3 In the same manner as in Comparative Example 2 except that the thread B was used in place of the thread A, forgery prevention paper having a degree of water penetration and expansion of 5.5% was obtained.

[Evaluation] 1000 sheets of each anti-counterfeiting paper processed into a lithographic plate were stacked at a temperature and humidity of 20 ° C. and 65% RH.
And a printing room set at 30 ° C. and 25% RH, and immediately subjected to a continuous printing test using an offset printing machine.
The printing operability at this time was evaluated based on the following criteria, and the results are shown in Table 1. ：: Curling was hardly observed, and the printing operability was extremely excellent. Good: Jamming rarely occurs due to curling, but there is no practical problem. Δ: Jamming due to curling frequently occurs, and continuous operation is difficult. . ×: The curl is severe and printing cannot be performed.

[0037]

[Table 1]

[0038]

As is clear from the results shown in Table 1, printing can be performed with almost no problem when the forgery prevention paper has a water penetration elongation of 3.8% or less, and when 3.8% to 4.3% is used, printing is slightly performed. It is understood that troubles due to curling are likely to occur, and if the ratio is 4.3% or more, printing may not be performed depending on conditions. Further, it can be seen that the curl is more likely to be deteriorated and the influence of printing conditions is more likely to be obtained when the thread B having a large width is used than when the thread A having a small width is used. From the above results, the present invention can manufacture anti-counterfeit paper having extremely excellent printability with existing equipment.

Continued on the front page (72) Inventor Tadashi Moriya 1 at Yanagicho, Shizuoka-shi, Shizuoka Pref.

Claims (1)

[Claims] An anti-counterfeit paper comprising a thread-like or tape-like base material and a thread provided with a thermoplastic and / or water-rewetting adhesive layer on one or both sides of the base material. 3. The degree of water expansion and contraction in the width direction of the paper is 4.
Thread-containing forgery prevention paper characterized by being 3% or less.