JP2002023643A - Pseudo adhesive form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems, such as the degradation in the strength on the front surface of a paper base material of pseudo adhesive paper and in the paper, the occurrence of a tear in paper and paper base material, the peeling of the pseudo adhesive layer, etc., by water, wetting with water and storage under high humidity. SOLUTION: This form has the pseudo adhesive layer which is adherable to at least a part of the front surface of the paper base material under specified conditions and is made peelable after adhesion in. A water repelling agent layer is formed between the paper base material and the pseudo adhesive layer. The coating weight of the water repelling agent is preferably regulated to 0.5 to 10 g/cm2 in dry weight and the paper base material is formed to >=50% in the coloration ratio of the mechanical pulp by the C dyeing liquid based on JIS P 8120.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for adhering under certain conditions without adhering under normal conditions.
The present invention relates to a pseudo adhesive sheet that can be easily peeled off when necessary.

[0002]

2. Description of the Related Art Conventionally, when a certain condition such as pressure is applied to a superimposed surface, an adhesive layer is adhered to the superposed surface.
Widely used for envelopes, postcards, various types of direct mail, delivery slips, labels, etc.

Such a letter or postcard is mailed in such a manner that one sheet of paper is folded so as to have a superimposed surface, or two sheets of paper are superimposed, and the superposed paper is quasi-adhered to conceal information. Then, the receiver peels off the superposed paper and reads the concealment information. These communication methods that require confidentiality include, for example, the company
Alternatively, it is used when a bank or a credit company communicates confidential information to a customer.

Such a pseudo-adhesive paper has a so-called non-peelable adhesive such as a natural rubber, a synthetic rubber, or a rubber latex thereof on at least a part of one side of a paper substrate, and suppresses the adhesive force of the adhesive. It is provided with an adhesive layer (hereinafter, referred to as a pseudo-adhesive layer) composed of a fine particle filler, and has a function that can be temporarily bonded but can be easily peeled off when necessary.

The quasi-adhesive paper is wetted by rain or the like during mailing, or is stored under high humidity, so that the surface of the paper base material and the strength in the paper are reduced, and the paper is torn or damaged. It has become clear that problems such as breakage of the base material and peeling of the pseudo adhesive layer occur. The end result is damage or blurring or even loss of information.

As a countermeasure for this, Japanese Patent Application Laid-Open No. 7-276
Japanese Patent Application Laid-Open No. 7-858 discloses a means for increasing the strength of the paper substrate itself.
In -309086, it is proposed to take measures against water.

[0007]

However, the former disclosed in Japanese Patent Application Laid-Open No. Hei 7-276858 can provide a sufficient adhesive force between the paper base and the adhesive layer even if it is useful for strengthening the paper base. No consideration has been given to the absence.

On the other hand, Japanese Patent Application Laid-Open No. Hei 7-309086 discloses a method of using synthetic paper as a base material, a method of using a base material in which a wet paper strength enhancer is added to paper as specific means for imparting water resistance, and Three methods of forming a water-resistant treatment layer in which a water-resistant agent and a binder are crosslinked on the surface of paper have been proposed.

[0009] However, in the case of the method in which the base material is made of synthetic paper, the paper is of a completely different type from paper generally used for this type of paper, and is difficult to reuse. It has decisive problems, such as high cost, and is difficult to adopt except for special uses.

In this respect, the method of internally adding a wet paper strength enhancer and the method of forming a water-resistant treatment layer in which a water-resistant agent and a binder are crosslinked are both practical methods. Problems exist. First, in the case of the method in which the wet paper strength enhancer is internally added, a) general foam paper and high-quality paper cannot be used, and special papermaking conditions are required, so that the production cost increases. b) The water resistance is most important at the interface between the adhesive layer and the base paper. However, when the wet paper strength enhancer is simply added to the base paper, sufficient adhesive strength between the adhesive layer and the base paper is obtained. Cannot be obtained, and the adhesive layer is peeled off from the base paper when peeled off again after being wet with water, so-called glue cracking occurs. c) In order to increase the adhesive strength, it is necessary to intentionally increase the internal addition amount of the wet paper strength agent, but this leads to an increase in cost. d) When a wet strength agent is internally added during the papermaking process, it is necessary to stabilize the wet strength agent over time, and careful management is required in the manufacturing process and inventory control. e) It has no effect on storage under high humidity or measures against an increase in pseudo-adhesive strength that occurs when wet and dried.

On the other hand, in the case of a method of forming a water-resistant treatment layer in which a water-resistance treatment agent and a binder are cross-linked, A) When applying the water-resistance treatment layer, the water-resistance treatment agent and the binder are mixed before coating. A reaction occurs and a coating defect occurs, making the coating difficult. B) Due to the water-resistant effect of the adhesive layer, an effect can be expected to increase the peel strength when dried after wetting, but since the water-wetting strength of the paper base material itself is not considered at all, water-wetness is obtained. At this time, the strength of the paper substrate is reduced, and paper tearing occurs. C) Due to the extremely high air permeability due to the formation of the water-resistant treatment layer, curling occurs and the suitability for printing and processing is reduced. D) Use of a waterproofing agent causes an increase in chemical cost. E) When the exemplified water-proofing agent and the binder are mixed, foaming often occurs, resulting in poor workability. F) Due to the presence of the water-proofing agent, the dispersibility of the fibers at the time of recycling the paper becomes poor, and the recycling becomes difficult.

Accordingly, it is an object of the present invention to provide a pseudo-adhesive sheet which solves the above-mentioned problems and provides the following advantages.

[0013]

According to the first aspect of the present invention, which solves the above-mentioned problems, it is possible to adhere to at least a part of the surface of a paper base under certain conditions, and to peel off after adhesion. A paper having a pseudo adhesive layer which is made possible, wherein a water repellent agent layer is formed between the paper base and the pseudo adhesive layer.

According to a second aspect of the present invention, the applied amount of the water repellent is 0.5 g to 10 g / m ² in dry weight.
It is a pseudo adhesive paper as described.

The invention according to claim 3 is characterized in that the paper base material is J
The coloration ratio of the mechanical pulp with the C dyeing solution based on ISP8120 is 50% or more.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a pseudo adhesive sheet according to the present invention will be described in detail. First, a preferred use form of the pseudo adhesive sheet according to the present invention will be described with reference to the accompanying drawings.

The folding pseudo-adhesive feeding envelope shown in FIG.
A pseudo-adhesive layer 2 is provided on the surface of a paper base material 1, and after feeding information is printed on the pseudo-adhesive layer 2, as shown in FIG. The valley is folded in two from the center line of the printing surface in the printing direction, and is pressure-bonded. Address information 4 and the like are printed on the back surface.

In the tri-fold postcard shown in FIG. 2, pseudo adhesive layers 2 and 2 are formed on the front and back surfaces of a paper substrate 1, and concealed information 3, communication information and address information 4 are printed on the front surface. Figure (B)
As shown in (1), the address printing surface is folded in a Z-shape so that the printing surface is the front surface, and pressure bonding is performed.

The two-fold postcard shown in FIG. 3 and the partially folded postcard shown in FIG. 4 form a pseudo-adhesive layer 2 on the inner side of the fold of the paper substrate 1, print information, and fold and add. In this method, the pseudo-adhesive layers are overlapped with each other and pressure-bonded.

In the above example, the recipient of the mailing address can read the hidden print information by opening the pseudo adhesive surface.

The pseudo-adhesive paper of the present invention is widely and suitably used for purposes other than those listed above. For example, the present invention is suitably used for various postcards, sealed letters, reports, and also applies a pseudo adhesive only to a part of a paper base material, or provides a non-coated part to a part. By doing so, it is possible to facilitate re-peeling. The pseudo-adhesive paper of the present invention is suitably used as a folding pseudo-adhesive paper, a superimposed pseudo-adhesive paper, an information concealing paper having a confidential property, a confidential postcard, a confidential envelope, and the like.

As the paper base material of the pseudo adhesive paper according to the present invention, so-called coated paper such as art paper, coated paper, lightweight coated paper, etc. may be used in addition to foam paper, high quality paper and medium quality paper. it can. As a paper base material, JISP81
Color ratio of mechanical pulp by C dyeing solution based on No. 20 is 5
When pulp of 0% or more is used, the opacity is higher than ordinary high-quality paper when compared at the same basis weight, and is suitable for applications such as postcards for transmitting confidential information.

It is effective to apply a starch to these paper base materials as necessary using a size press or the like to increase the surface strength.

In the present invention, the non-peelable adhesive used as the base of the pseudo-adhesive is a latex, specifically, a conventional ordinary pressure-sensitive adhesive such as a natural rubber, a synthetic rubber or a synthetic resin. Can be used arbitrarily selected from those used for natural rubber, especially natural rubber latex mixed with methyl methacrylate, sulfur-free vulcanization, and methyl methacrylate grafted on natural rubber A natural rubber latex, an acryl-modified rubber latex, or a mixture of a rubber latex and a protective colloid-based acrylic copolymer emulsion obtained by polymerization is suitable in terms of blocking resistance, aging deterioration resistance, ink adhesion, and the like.

Also, the applicant of the present invention disclosed in Japanese Patent Laid-Open No. 7-292329.
, Polyethylene glycol may be added to the pseudo-adhesive base to improve the adhesion of the pseudo-adhesive.

Although the above description is based on a pressure-sensitive adhesive, a heat-sensitive adhesive or a wet adhesive can also be used.

As the fine particle filler which suppresses the adhesive force of the non-peelable adhesive, all of the fine particle fillers generally used in the past can be used.

As the fine particle filler which suppresses the adhesive force of the non-peelable adhesive, all of the fine particle fillers generally used in the past can be used. Specifically, calcite-based precipitated calcium carbonate forming primary or secondary aggregates, aragonite-based precipitated calcium carbonate forming secondary aggregates, styrene beads, cereal starch, modified starch, synthetic Fine-particle silica, amino surface-modified silica, wax surface-treated silica, spherical silica, ordinary calcium, zinc, magnesium, oxides, hydroxides, carbonates or silicates of metals such as aluminum or titanium,
Or a mixture thereof. In particular, amino surface-modified silica exhibits excellent cationic properties and is excellent in ink fixability for inkjet printing. The wax surface-treated silica has an effect of improving the moisture resistance of the adhesive layer, and contributes to a reduction in the amount of the water repellent applied according to the present invention. In addition, a mixture of calcined kaolin clay and rice starch may be used.

As a method of applying the pseudo adhesive, an air knife coater, a blade coater, a curtain coater,
A coating by a coating method such as a bar coater, flexographic printing, screen printing or the like is suitable, and the surface of the adhesive is about 1%.
It is preferable to apply a pressure of 〜１０10 kg / cm ² to flatten excessive protrusion of the adhesive surface.

In any case, the pseudo-adhesive layer formed of the non-peelable adhesive of the above example formed on the surface of the paper base material does not normally adhere, and when a certain condition is given. It becomes possible to adhere.

In this case, certain conditions include:
Pressing under normal conditions, pressing while heating, heating when using a heat-sensitive adhesive, and wetting with water when using a wet paper strength agent can be mentioned. After bonding, the sheet facing the pseudo adhesive layer can be peeled off by hand.

In the embodiment of the present invention, a water-repellent agent layer is formed on the surface of the paper substrate on the side of the pseudo adhesive layer, and the pseudo adhesive layer is formed thereon. In forming the water repellent layer, an appropriate coating method such as a blade or an air knife method can be employed.

In this case, examples of the water repellent include acid chloride type water repellent, isocyanate type water repellent, ketene dimer type water repellent, pyridine condensed type water repellent, ethylene urea type water repellent, methylol compound Type water repellent, ethylene oxide type water repellent, silicon compound type water repellent, chromium complex compound type water repellent, titanium containing compound type water repellent, zirconium containing compound type water repellent, fluorine compound type water repellent, And a silicon compound type water repellent. As other water repellents,
Fats (vegetable oils, animal oils, vegetable fats, animal fats), higher aliphatic compounds (saturated or unsaturated acids, alcohols, esters, amines, amides, salts), waxes (vegetable wax, animal wax, mineral wax, Petroleum wax, modified wax) or the like, or a modified product thereof, or a mixture thereof. However, at least two or more isocyanates are added to the hydroxyl groups present in the paper and the pseudo adhesive layer. It is preferable to react a compound having a group to form at least one urethane bond.

Compounds containing two or more isocyanate groups in the molecule include paraphenylene diisocyanate, 2-chloro-1,4-phenyl diisocyanate,
2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalenediisocyanate, hexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 1,3-xylylene-4,6-diisocyanate, diphenylsulfide-4 , 4'-diisocyanate, 1,4-naphthalenediisocyanate, polymeric methylene diisocyanate, triphenylmethane triisocyanate, 1,3
6-hexamethylene triisocyanate, tris (isocyanate phenyl) thiophosphate and the like.

Further, the amount of the water repellent applied is desirably 0.5 to 10 g / m ² in terms of dry weight. If the amount is too small, the desired water repellency cannot be obtained, and if the amount is too large, not only the cost is increased but also the pseudo-adhesion is lowered, which is disadvantageous.

Subsequently, a pseudo adhesive layer is formed on the water repellent layer. As a result, the penetration stability of the adhesive in the pseudo-adhesive layer by butadiene, the hydroxyl group or carboxyl group reacts with the isocyanate group in the water repellent to enhance the adhesiveness, and the reaction is caused by the surface of the paper substrate. Since it also occurs in a part, the bonding of the paper substrate to the fibers is enhanced, and the adhesion and adhesion of the water-repellent layer and the pseudo-adhesive layer to the paper substrate are enhanced.

Next, examples will be shown to clarify the effects of the present invention.

[0038]

EXAMPLES The effects of the present invention will be clarified by examples. <Experimental example group> A high-quality paper was used as a base paper, and a predetermined amount of a polyester urethane water repellent (AP-40, manufactured by Dainippon Ink) was applied to the base paper as a water repellent to form a water repellent layer. 80 parts (dry weight) of natural rubber latex obtained by sulfur-free vulcanization of natural rubber and mixing with methyl methacrylate as a non-peelable pressure-sensitive adhesive, and an average particle diameter of 7 μm
m of synthetic silica (Carplex 80D, manufactured by Shionogi & Co., Ltd.) in an amount of 10 g / m ² (dry weight) on the water-repellent layer. By coating, pseudo adhesive papers according to the present invention of Examples 1 to 3 were produced.

<Example 1> Polyester-based urethane water repellents (AP-
40) was 0.5 g / m ² .

<Example 2> A polyester-based urethane water repellent (AP-
40) was applied at 5.0 g / m ² .

<Example 3> A polyester urethane water repellent (AP-
40) was set to 10.0 g / m ² .

<Comparative Example 1> A polyester urethane water repellent (manufactured by Dainippon Ink: AP-
40) was 0.3 g / m ² .

<Comparative Example 2> A polyester urethane water repellent (AP-
40) was 12.0 g / m ² .

<Comparative Example 3> Fine wood paper was used as the base paper.
Polyamide urea-formaldehyde resin 0.5 g / m ² on this substrate paper as waterproofing agents, water-resistant treatment layer polyvinyl alcohol in combination as comprising a 4.5 g / m ² to 5.0 g / m ² as a binder a Then, as a non-peelable pressure-sensitive adhesive, 80 parts (dry weight) of natural rubber latex obtained by sulfur-free vulcanization of natural rubber mixed with methyl methacrylate, and synthetic silica having an average particle diameter of 7 μm (Carplex 80D: A pseudo-adhesive composition prepared by mixing 20 parts of Shionogi Pharmaceutical Co., Ltd. was applied onto the water-repellent agent layer so as to have an application amount of 10 g / m ² (dry weight) to produce a pseudo-adhesive paper. .

<Comparative Example 4> As a base paper, a high-quality paper internally containing a wet paper strength enhancer in a papermaking stage was used, and then natural rubber was sulfur-free vulcanized as a non-peelable pressure-sensitive adhesive to form methyl methacrylate. The pseudo-adhesive composition obtained by mixing 80 parts (dry weight) of the mixed natural rubber latex and 20 parts of synthetic silica (Carplex 80D: manufactured by Shionogi & Co., Ltd.) having an average particle diameter of 7 μm was added to the wet paper strength. Pseudo-adhesive paper was manufactured by applying the coating amount to a high-quality paper with the agent added thereto so that the coating amount was 10 g / m ² (dry weight).

Comparative Example 5 Fine paper was used as the base paper, and then 80 parts (dry weight) of a natural rubber latex obtained by sulfur-free vulcanizing natural rubber and mixing with methyl methacrylate as a non-peelable pressure-sensitive adhesive were used. A pseudo-adhesive composition obtained by mixing 20 parts of synthetic silica (Carplex 80D, manufactured by Shionogi & Co., Ltd.) with an average particle diameter of 7 μm was applied to the high-quality paper so that the application amount was 10 g / m ² (dry weight). To produce a pseudo-adhesive paper.

The following experiments were performed on each of these pseudo-bonded papers. [Fiber peeling] Each sample had an adhesive strength of 10 cm at a width of 5 cm.
After being press-bonded so as to have a weight of 0 g, it is immersed in water. After 24 hours, the paper is pulled out of the water, excess water on the paper surface is removed with a filter paper, and the paper is peeled again. The peeling surface after re-peeling was observed to observe the fiber peeling. (Evaluation criteria) ：: no fiber is removed, Δ: fiber is partially removed, paper surface is fluffy, ×: paper is completely torn [adhesion between adhesive layer and base paper] Each sample is pressure-bonded so that the adhesive strength at a width of 5 cm becomes 100 g, and then immersed in water. After 24 hours, the paper is pulled out of the water, excess water on the paper surface is removed with a filter paper, and the paper is peeled again. The peeled surface after re-peeling was observed, and the peeling of the fibers and the adhesion between the pseudo adhesive and the water-repellent-coated base paper were determined. (Evaluation criteria) ：: no glue is removed, Δ: glue is removed in dots, ×: adhesive layer is peeled off from paper [pseudo-adhesive force] Mail sealer (MS-9100: Dai Nippon Printing) Using a roll gap 14 (140 μm).
m), and the pseudo adhesive force was measured by a T-type peel test. (Evaluation criteria) ：: 200 gf / 50 mm or more, Δ: 5
0 to less than 200 gf / 50 mm, ×: 50 gf / 50 m
Less than m [Paper permeability] Air permeability was measured on the pseudo-adhesive paper after applying the pseudo-adhesive in accordance with JISP8117. (Evaluation Criteria) ２００: less than 200 seconds, Δ: less than 200 to 300 seconds, ×: 300 seconds or more [Production cost] The cost of the chemical used was estimated and evaluated.

[0048]

[Table 1]

[0049]

As apparent from the above description, the following advantages can be obtained according to the present invention. (1) Pseudo-adhesive paper with improved water resistance can be obtained by using general paper such as foam paper and high-quality paper. (2) Since the film is not formed on the surface of the paper substrate as in the conventional example, the paper has excellent air permeability, no curl, and excellent printability and processability. (3) Good pseudo-adhesion can be obtained, for example, because the water-repellent agent reacts with the hydroxyl group in the adhesive. (4) As compared with the case where the wet paper strength enhancer is internally added to the paper base material, the amount of the used chemical agent (water repellent) can be reduced, and
Despite the small amount of chemicals (water repellents) used, they exhibit excellent water resistance. (5) In the case of a water repellent, application can be performed without generating foaming, and workability is improved. (8) The cost of chemicals used can be reduced, and an increase in papermaking costs can be suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a folded-feed envelope.

FIG. 2 is an explanatory diagram of a tri-fold postcard.

FIG. 3 is an explanatory diagram of a two-fold postcard.

FIG. 4 is an explanatory diagram of a partially folded postcard.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base paper, 2 ... Pseudo-adhesive layer, 3 ... Information printing surface, 4 ...
Address information

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D21H 21/16 D21H 21/16 27/00 27/00 A G09F 3/02 G09F 3/02 Z 3/03 3/03 EF term (reference) 2C005 WA03 4F100 AK51 AK51G BA03 BA05 BA06 BA07 BA10A BA10C DG10A EH46 EH462 GB90 JB06 JB06B JB06D JL11 JL11C JL11E YY00C YY00E 4J004 AA05 AA18 BE01 CB02 CD01

Claims (3)

[Claims] 1. A paper sheet having a pseudo-adhesive layer which can be adhered to at least a part of the surface of a paper base under certain conditions and which can be peeled off after bonding. A pseudo-adhesive paper, wherein a water-repellent layer is formed between the pseudo-adhesive layer and the pseudo-adhesive layer. 2. The method according to claim 1, wherein the water repellent is applied in an amount of 0.5 to 0.5% by dry weight.
Pseudo adhesive sheet according to claim 1, wherein a 10 g / m ^2. 3. The pseudo-adhesive paper according to claim 1, wherein the paper substrate has a coloration ratio of mechanical pulp of 50% or more by a C dyeing solution based on JISP8120.