JP2001105724A - Pseudo-pressure bonding sheet for ink jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remarkably improve color developing clarity, ink absorbability, glossiness, adhesive properties and yellowing preventiveness of an ink jet ink adhered to a pseudo-pressure bonding sheet, and to eliminate transfer of printing to an opposite surface in the case of releasing. SOLUTION: The pseudo-pressure bonding sheet for ink jet recording comprises a light-gravity calcium carbonate having a specific surface area of 50 to 100 m2/g and a mean particle size of 1 μm or less by a BET method and contained in a pseudo-adhesive obtained by adding a fine particle filler to a non-releasable pressure sensitive adhesive, and a water soluble metal salt having a bivalent or more valence number or one or more types of an oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pseudo-pressed paper for ink-jet recording which has a function of being printed by an ink-jet printer and temporarily bonding, but having a function of being easily peeled off when necessary.

[0002]

2. Description of the Related Art In recent years, while the amount of information transmitted through communication means such as communication and mailing has increased, communication means requiring confidentiality such as personal information have been emphasized and demanded.

Further, with the revision of the Postal Law, postcard systems having confidentiality have been put into practical use and have begun to spread. This confidential postcard system folds a reciprocating postcard with various information such as personal information written on the inner surface, folds the overlapped portion, conceals the information, mails it, and receives it. This is a system in which a person peels off a pseudo-adhesion part and reads concealment information. These confidential communication methods include, for example, a company contacting an employee and a bank or credit company contacting a customer that requires confidentiality.
The major issues are prevention of leakage of the confidentiality information, convenience of information communication, and ease of opening.

Conventionally, a thermoplastic resin layer is provided on a support,
After printing the confidential information, the confidentiality is obtained by a method in which the resin layers are opposed to each other and heated and joined, or a method using a heat-sensitive or pressure-sensitive non-peelable adhesive. These types of methods using heat bonding, heating or pressure-sensitive non-peelable adhesives are capable of mass processing using computers and printers, and are in increasing demand.

[0005] However, heating bonding, bonding with a heat-sensitive or pressure-sensitive non-peelable adhesive have the above-mentioned convenience,
There are problems such as the necessity of perforation in order to avoid breakage of necessary parts at the time of opening, the generation of cut pieces at the time of opening, and the inability to use the postcard system.

As means for solving these problems, the second
There has been proposed an information stack which can be mailed as a fixed form mail, an example of which is disclosed in JP-A-4-59395. In this method, at least a part of the support sheet surface is provided with an adhesive layer comprising a conventionally used non-peelable adhesive base and a fine particle filler having an incompatibility with the adhesive base. It is a thing. this is,
For example, it is temporarily adhered by applying a high pressure, but has a function that can be easily opened when necessary. A material having such a function is referred to as a pseudo-crimp paper in this specification, The adhesive used for is called a pseudo adhesive.

[0007] When printing on this pseudo pressure-bonded paper,
Conventionally, printing of non-confidentiality information, for example, frame lines and greetings, is performed by offset printing using a form printer. After that, for information that has confidentiality for each individual, such as the amount of borrowed money described in the communication made to the customer from the credit company etc.
Printing has been performed by a printing method that performs electrical processing, for example, an electrostatic non-impact printer.

[0008]

On the other hand, in recent years, recording all non-confidentiality information and confidentiality information by an ink jet printer in several steps has been aimed at. The use of an ink jet printer has the advantage of being able to handle large-lot prints at a higher speed than conventional printing methods. In addition, it is not necessary to create a printing plate for offset printing, and data entry and correction can be easily performed with a personal computer, regardless of confidentiality information or non-confidentiality information. There is also an advantage that the number of steps for creating a postcard is reduced.

Further, the printing processing speed of the conventional non-impact printer is about 50 m / min, but the ink jet printer is about 150 m / min. are doing. However, as needs diversify,
Demands for increasing the size and speed of printers and increasing the definition of recorded images have been particularly increasing.

[0010] However, the conventional pseudo pressure-bonded paper has no consideration for printing with an ink jet printer. Therefore, when printing is performed with an inkjet printer, the fixability of the inkjet ink to the pseudo adhesive layer is poor, and there are problems in the color clarity, gloss, fading, and light resistance of the ink.

Therefore, an object of the present invention is to improve the fixability of an ink jet ink on a pseudo-compression-bonded paper, thereby improving color development, gloss, fading, and light resistance.
An object of the present invention is to provide a pseudo-pressed paper for inkjet recording which is low in manufacturing cost.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a support sheet comprising a non-peelable pressure-sensitive adhesive as a basic component and a pseudo-adhesive layer containing a fine particle filler. In the pseudo pressure-bonded paper formed on at least a part of at least one side of the above, the pseudo adhesive has a specific surface area by BET method of 50 to 100 m ² / g, an average particle size of 1 μm or less, and light calcium carbonate and divalent or more ions. It is characterized by containing one or more of a valent water-soluble metal salt and an oxide.

The quasi-adhesive layer in the conventional quasi-crimp paper is anionic, and the ink jet ink is also anionic. Therefore, when the pseudo-adhesive layer is sprayed with the ink-jet ink, the pseudo-adhesive layer and the ink-jet ink repel each other, and it is considered that the repulsion causes deterioration of color clarity, gloss, fading, and light resistance. Can be

Therefore, for example, it is thought that if a cationic ink fixing agent commonly used in ink jet recording paper is added to the pseudo adhesive layer, the ink jet ink can be fixed. However, if the cationic ink fixing agent was mixed with the pseudo-adhesive, the pseudo-adhesive and the ink fixing agent reacted and aggregated before being applied to the support sheet. It has been found that it is no longer possible to apply it to the surface.

Based on these findings, further studies have been continued. In order to improve the color vividness, glossiness, fading, and light resistance without causing aggregation with the pseudo-adhesive, the pseudo-adhesive layer was subjected to the BET method. It has been found that it is effective to contain light calcium carbonate having a specific surface area of 50 to 100 m ² / g and an average particle size of 1 μm or less.

However, ink jet inks generally have a tendency to gradually discolor when exposed to sunlight or left indoors. In particular, the use of light calcium carbonate having a specific surface area of 50 to 100 m ² / g and an average particle size of 1 μm or less requires a high surface area. Due to the adsorption of oxides and the like in the air due to the activity, the discoloration and fading of the inkjet ink may be accelerated, and the discoloration and light resistance may be deteriorated. As a result of further studies, they have found that improvement in fading and light resistance can be solved by containing at least one kind of a water-soluble metal salt or oxide having an ionic valence of 2 or more, thereby completing the present invention. Reached.

According to the present invention, light calcium carbonate having a specific surface area of 50 to 100 m ² / g according to the BET method, an average particle size of 1 μm or less, and a water-soluble metal salt having an ionic valence of 2 or more are mixed with the pseudo-adhesive. However, they do not agglomerate and can therefore be applied to a support sheet.

On the other hand, the specific surface area by the BET method is 50 to 1
Light calcium carbonate having a particle size of 00 m ² / g and an average particle size of 1 μm or less tends to have a higher density of ink-jet printed dots as the specific surface area becomes smaller. Is more preferably 50 to 80 m ² / g. However, 50 m ² / g
If it is lower, the absorbability of the ink-jet ink deteriorates.

On the other hand, when the specific surface area is larger than 100 m ² / g, the discoloration of the ink tends to be inferior, so that the cost is high and industrial use is difficult.

The average particle size is preferably as small as possible from the viewpoint of increasing the definition and density of ink-jet printed dots, but is naturally limited in terms of industrial production costs. If the average particle size is larger than 1 μm, there is a problem that the pseudo-adhesion is hindered.

Therefore, the specific surface area by the BET method is 5
By forming a pseudo-adhesive layer containing light calcium carbonate having a particle size of 0 to 100 m ² / g and an average particle size of 1 μm or less on a support sheet, an ink jet having excellent color clarity, gloss, fading, and light fastness is provided. It is possible to obtain a pseudo-pressed paper for recording.

Specific examples of the water-soluble metal salt and oxide having an ionic valence of 2 or more include magnesium, calcium, strontium, titanium, zinc, cadmium,
Carbonates, silicates, such as mercury, iron, cobalt, nickel, etc.
And oxalates, but also include those mainly composed of these weak acid salts in chemical structure. In particular, titanium oxide, calcium silicate, magnesium silicate, zinc carbonate, calcium carbonate, and magnesium oxide are desirable for the present invention.

The addition amount of these substances is 0.1 to 20 parts, particularly preferably 1 to 15 parts, of the divalent metal salt or oxide and 100 parts of calcium carbonate, and calcium carbonate is added to water. May be mixed at the same time when dispersing, or may be separately dispersed and mixed at the time of liquid preparation.

The ink jet recording ink which can be used in the present invention is described in, for example, JP-A-7-2
Nos. 28808 and 7-228809 can be used. In particular, anthraquinones,
Benzoquinone, naphthoxyquinone, xanthene,
Triphenylmethane, quinoline, indigoid,
At least one anionic ink selected from the group consisting of azine-based, oxazine-based, thiazine-based, and methine-based inks is suitably used. Regarding these specific examples, see paragraph 0015 of JP-A-7-228809.
Is exemplified. As a medium used in the ink, a mixed solvent of water and a water-soluble organic solvent can be used. In addition, a pH adjuster, a viscosity adjuster, a surface tension adjuster and the like can be contained.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. Examples of the pseudo-pressed paper for inkjet recording according to the present invention include the following. That is, the folding pseudo-adhesive supply envelope shown in FIG. 1 is provided with the pseudo-adhesive layer 2 on the surface of the support sheet 1, and after printing the supply information on the pseudo-adhesive layer 2,
(B) As shown in the figure, the information printing surface 3 is folded into two valleys from the center line in the printing surface printing direction on the inner surface, 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 support sheet 1, and concealing information 3, communication information and address information 4 are printed on the surface (B). )
As shown in the figure, folding and pressure bonding are performed so that the address printing surface is the front surface.

The two-fold postcard shown in FIG. 3 and the partially folded postcard shown in FIG. 4 form a pseudo-adhesive layer on the inner side of the folding of the support sheet 1, print information, fold and press-bond. In each case, the pseudo adhesive layers are overlapped with each other and pressure-bonded.

In addition to the applications listed in these examples, it is widely and suitably used for various postcards, envelopes, and reports.
Re-peeling can also be facilitated by providing a partially non-coated portion. The pseudo-pressed paper for ink jet recording of the present invention,
In addition to the quasi-compression paper for folding ink jet recording and the quasi-compression paper for overlay ink jet recording, it is suitably applied as confidential information concealing paper, confidential postcard, confidential envelope and the like.

The support sheet used in the present invention is not particularly limited, and examples thereof include woodfree paper mainly composed of cellulose fibers and various synthetic papers.

The pseudo adhesive used in the present invention is:
Basically, a non-peelable pressure-sensitive adhesive base is added with a fine particle filler for imparting pseudo-adhesiveness. It is constituted by blending a base resin.

The non-peelable pressure-sensitive adhesive base (hereinafter referred to as “pressure-sensitive adhesive”) used in the present invention includes:
Latex, specifically, natural rubber, synthetic rubber and the like can be arbitrarily selected and used from those conventionally used in ordinary pressure-sensitive adhesives. Natural rubber latex mixed with methyl methacrylate, natural rubber latex obtained by graft polymerizing methyl methacrylate on natural rubber, acrylic modified rubber latex, a mixture of rubber latex and protective colloidal acrylic copolymer emulsion, It is suitable in terms of blocking resistance, deterioration over time, and the like.

The fine particle filler to be added to the pressure-sensitive adhesive in order to provide a pseudo-adhesive force is, in addition to the calcium carbonate of the present invention, a water-soluble metal salt having an valence of at least two, and an oxide. A fine particle filler having incompatibility with the pressure-sensitive adhesive can be used. Specifically, those having a small affinity for the pressure-sensitive adhesive, for example, kaolin, talc, silica, urea resin, styrene beads, calcined clay, cereal starch, silica gel, modified starch and the like can be suitably used. Among them, it is particularly preferable to use two or more kinds having different particle diameters in combination. As other auxiliaries to be added to the pseudo adhesive, a lubricant, a printability improver, an antioxidant, an ultraviolet absorber, a conductive agent, a coloring ink, a preservative, a humectant, and the like can be added as required.

The pseudo pressure-bonded paper for ink jet recording of the present invention is obtained by providing a layer of the pseudo adhesive composition on at least a part of one side of a support sheet. In order to obtain the surface and printability, bend blade, tip blade, comma, lip or air knife, curtain coater, roll coater, coating by a known coating method such as a gravure coater is performed, and the pseudo adhesive surface is about 1 to 10 kg. / Cm ² is preferably applied.

[0034]

Embodiments of the present invention will be described below in detail. 35% by weight of natural rubber latex, silica,
40% by weight of a fine particle filler consisting of wheat starch and calcined clay, and 15% by weight of other auxiliaries were added to a pseudo-adhesive base in accordance with the amounts of Examples and Comparative Examples shown in Table 1. Pseudo-adhesives were made with or without calcium carbonate. In addition to these Examples and Comparative Examples, the metal salts or oxides shown in Table 2 were further blended into the pseudo-adhesive in accordance with the blending amounts, and applied to one surface of a support sheet made of high-quality paper 130 g / m ^2. To produce a pseudo-pressed paper for ink jet recording. Printing was performed on these pseudo-pressed papers for ink-jet recording by an ink-jet printer, and each of Examples and Comparative Examples was evaluated for color clarity, gloss, fading, and light resistance. In addition, as an inkjet printer, BJC manufactured by Canon Inc.
-820 J was used. Color development: Using a stereoscopic microscope, ink bleeding around dots was visually determined. ：: no bleeding, ○: almost no bleeding, Δ: bleeding was observed, ×: much bleeding Absorbency of ink: ink-jet ink was printed in bulk in four colors, and tissue paper was pressed against the solid part immediately after printing. The transfer of the ink to the tissue paper was visually observed and judged. ：: no transfer, ：: almost no transfer, Δ: transfer observed, ×: many transfer Evaluation of glossiness According to JIS-P8142 measurement method, gloss meter GM
26D (manufactured by Murakami Color Difference Research Laboratory). Evaluation of adhesive strength: The support sheet on which the pseudo-adhesive layer was formed was humidified at 20 ° C. and 50%, folded in two, and bonded by a bonding machine. The peeling was performed at a speed of 600 mm / min with a peeling machine, and the peeling state was observed. ◎: good re-peeling, ：: slight removal of adhesive layer, Δ: partial removal of adhesive layer, ×: peeling of adhesive layer

[0035]

[Table 1]

As can be seen from Table 1, in Examples 1 to 5 containing light calcium carbonate having a specific surface area of 50 to 100 m ² / g and an average particle size of 1 μm or less according to the BET method, the color clarity, gloss, and There was no inferior fading and lightfastness. However, in Examples 1 to 5 using calcium carbonate, Example 5 having a specific surface area as large as 100 m ² / g resulted in poor adhesion. Example 1
Although not as great, in Example 3 where the blending amount is still small,
The results were slightly inferior in color clarity, ink absorption, gloss and fading, and light fastness. On the other hand, Comparative Examples 2, 4, and 5 having a low specific surface area resulted in markedly inferior color clarity, ink absorbency, glossiness, fading, and light fastness. Further, in Comparative Example 3 using calcium carbonate composite silica, although the color clarity and ink absorbability were good, there was a problem that the adhesiveness was remarkably deteriorated, so that it could not be put to practical use. Further, those without addition of calcium carbonate could not be evaluated because of lack of adaptability of ink jet printing.

[0037]

[Table 2]

The evaluation of the discoloration was carried out by printing four ink jet inks in bulk and leaving them in an office for 7 days for 1 month, and then measuring their color density using a Macbeth densitometer (RD9).
The recording density was measured in 15). For the evaluation of light fastness, four colors of ink jet ink were printed, and after 4 hours and 8 hours with a carbon arc lamp, the color density was measured by Macbeth densitometer (RD915).

As can be seen from Table 2, when a water-soluble metal salt or oxide having an ionic valence of 2 or more is added to the pseudo-adhesive layer, the effect of improving both the fading property and the light resistance can be recognized. it can.

[0040]

As described above, according to the present invention, the fixability of the ink-jet ink to the pseudo-pressed paper for ink-jet recording can be improved. As a result, it was possible to remarkably improve the color clarity, glossiness, fading, and light resistance of the inkjet ink adhered to the pseudo-pressed paper for inkjet recording.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a folded pay 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.

[Tax of sign]

1 ... Support sheet, 2 ... Adhesive layer, 3 ... Information printing surface, 4 ... Address information.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09J 201/00 D21H 27/00 A D21H 27/00 B41J 3/04 101Y (72) Inventor Hiroyuki Shioda Ehime 5-1 Kamiyacho, Iyo Mishima City Daio Paper Co., Ltd.

Claims (1)

[Claims] 1. An ink jet recording method wherein a layer of a pseudo-adhesive containing a fine particle filler in a base containing a non-peelable pressure-sensitive adhesive as a basic component is formed on at least a part of at least one surface of a support sheet. In the pseudo pressure-bonded paper for use, the pseudo adhesive has a specific surface area of 50 to 100 m ² / g by a BET method,
A pseudo-pressed paper for ink jet recording, comprising light calcium carbonate having an average particle size of 1 μm or less and at least one water-soluble metal salt or oxide having an ionic valence of 2 or more.