JP2007237550A - Paper for contact-bonding postcard for inkjet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide paper for a contact-bonding postcard for inkjet recording which is excellent in the printing density and the water resistance/clarity of an inkjet recording image printed by a high-speed rotary system, especially in the water resistance/clarity in regard to full-color ink, and enables prevention of a ghost. <P>SOLUTION: An ink fixative which is the main constituent of an adhesive layer is an alkylamine/epichlorohydrin polycondensate of which the quaternarizing rate by a colloidal titration method is 84% or above, and moreover the number-average molecular weight thereof is made 500-2,000. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive postcard paper that is excellent in printing density, water resistance and sharpness of a full-color ink jet recording image printed by a high-speed rotary method, and that does not transfer the printed image to the opposite surface even after peeling. . The pressure-bonded postcard paper described here is a pressure-sensitive adhesive that does not exhibit adhesiveness or adhesiveness under normal conditions, exhibits adhesiveness when pressed, and can be peeled off after pressure bonding (hereinafter referred to as “crimping”). This is a postcard paper having an adhesive layer as a main component provided on a base paper.

In recent years, while the amount of information transmitted by communication means such as communication and mail has increased, there has been a demand for contact means that require confidentiality such as personal information. With the revision of the postal code, postcards that are less expensive than sealed letters and that can maintain confidentiality of communications as well as sealed letters have been developed and are beginning to spread.
This confidential postcard paper is printed with color inks of standard items (content explanations, cautions, requests, etc.), and then the address (recipient's address, name, etc.) Fold the paper on which personal information (password, membership number, billing amount, deposit balance, etc.) is recorded on the adhesive layer, which is the front side, or fold on it (called the 6 side type). Folded with a confidential face inside, concealed the information so that it can be removed again, concealed the information, and then mailed the recipient to peel off the removable part and read the personal information This is a postcard paper (see Patent Documents 1 and 2).

  The quality required for such a pressure-bonded postcard paper is as follows: (1) There is little deterioration due to ultraviolet rays or heat, and the stability of peel strength is excellent. (2) Excellent color ink fillability and printing durability. (3) In the 6-side type specification, there is no blocking between the adhesive layer surfaces, and there is no transfer of the adhesive layer to the preheat plate in laser printer printing (hereinafter referred to as adhesion of glue paste). In order to obtain these qualities, it is very important to select main components such as a pressure-sensitive adhesive, a fine particle filler, and a binder that form an adhesive layer of a pressure-bonded postcard paper, and additives such as a deterioration inhibitor.

Conventionally, as pressure-sensitive adhesives, natural rubber derivatives obtained by grafting unsaturated monomers such as methyl methacrylate and styrene on natural rubber have been mainly used.
That is, natural rubber derivatives are characterized by maintaining a high degree of self-adhesion and exhibiting adhesiveness but low tackiness when they are brought into contact with each other and pressure is applied. Grafting increases the polarity of the molecule and increases the anchoring force for hydrophilic substances.
If an adhesive layer of natural rubber derivative alone is provided on the base paper, it will not be suitable for color ink printing, and will generate blocking, or glue will adhere to the preheated plate, so kaolin, calcium carbonate, amorphous synthetic silica, starch particles are usually used. An air knife that is generally an aqueous coating system in terms of ease of preparation, economy, safety, etc. as a coating liquid by appropriately combining particulate fillers represented by Apply with a coater to provide an adhesive layer.

By the way, as a method for printing on the address side or confidential personal information side of the crimped postcard paper, a water-soluble ink fixing type ink jet printer method capable of printing by a high-speed rotary method has been recently adopted instead of the toner fixing type laser printer method. ing.
As the water-soluble ink to be used, for example, ink such as ink # 1000 in the order of Kodak Versamark (hereinafter referred to as Versamark ink), specifically, ink such as # 1040 black and # 1069 black is the most prominent. The characteristic of the Versamark ink is that the solid content of the ink is 4 to 7% by mass, and most of the ink other than the dye is water, and the dielectric constant is excellent. In addition, the solid content of water-soluble ink in general inkjet printers is 15% by mass or more. In addition to dyes and water, a relatively high amount of non-volatile high-boiling solvents are contained to prevent drying of the ink cartridge head. It is very different from the method ink.

In addition to the quality required for the pressure-sensitive postcard paper for high-speed rotary inkjet recording, (4) the print density of the ink recorded image is high. (5) The water resistance and clearness of the ink recorded image are excellent. (6) Ink absorption during ink printing is fast. (7) Even if it peels after pressure bonding, the ink print image of a confidential surface does not transfer to an opposing surface (henceforth ghost prevention) etc. are mentioned. More recently, for example, Versamark ink # 2000 series, specifically # 2001 cyan, # 2002 magenta, # 2003 black, # 2004 yellow and other full color inks have excellent print density, water resistance, sharpness, and ghosting. Prevention is an important item.
Ink-fixed and water-resistant technology for ink-jet printed images includes a releasable adhesive composition containing a cationic polymer that is an ink fixing agent to charge the dye molecules in the ink and charge the ink and ink. Van der Waals forces act between the agents, fixing the dye molecules to the releasable adhesive layer.

Accordingly, various proposals have been made as cationic polymers that are ink fixing agents. These suggestions are shown below.
Proposal 1: A composition for an adhesive layer containing a cationic polymer whose charge changes from zero to negative in a high pH range and a cationic polymer holding a positive charge and a polyvalent metal salt has been proposed. (See Patent Documents 3 and 4). However, these proposals are insufficient for water resistance and sharpness of printed images, particularly for full-color use.
Proposal 2: Proposal of an adhesive layer composition containing polydimethylamine / epichlorohydrin and / or modified dimethylamine / epichlorohydrin polycondensate having a molecular weight of 10,000 to 100,000 and a cation equivalent of 6.0 to 7.5 meq / g. (See Patent Document 5). However, even in this proposal, the water resistance and sharpness of the printed image, particularly the water resistance of full-color magenta ink (# 2002) is insufficient.

Proposal 3: Although a proposal has been made that 5-100 parts by mass of either a polyamide / epichlorohydrin resin or a water-soluble modified polyamine resin is contained with respect to 100 parts by mass of the natural rubber emulsion (see Patent Document 6), Gelation due to the addition of a cationic polymer during preparation of the adhesive layer coating liquid, water resistance and sharpness, especially water resistance, sharpness and ghost of the full-color ink intended by the present inventors were insufficient. In addition, when the addition amount is increased, there is a problem that the peel strength decreases.
Japanese Patent Laid-Open No. 3-90394 Japanese Patent Laid-Open No. 3-169596 JP-A-9-157611 Japanese Patent Laid-Open No. 10-879 Japanese Patent Application Laid-Open No. 10-52985 JP-A-10-337980

  The present invention provides a pressure-sensitive postcard paper for ink-jet recording, which is excellent in print density, water resistance and sharpness of an ink jet recording image printed by a high-speed rotary method, and particularly excellent in water resistance, sharpness and ghost prevention of full-color ink. It is.

  Under normal conditions, neither adhesiveness nor adhesiveness is shown. Adhesive layer is provided by applying a composition for pressure-sensitive adhesives, fine particle fillers, and ink fixing agents that can be peeled off under pressure. In addition, the ink fixing agent is an alkylamine / epichlorohydrin polycondensate having a quaternization rate of 84% or more by a colloid titration method, and the object is achieved. By setting it to 2000, the present invention has been reached with the knowledge that a remarkable effect can be obtained.

  In the pressure-sensitive postcard paper for ink-jet recording provided with the adhesive layer composition and the adhesive layer, the print density of the ink-jet recording image printed by the high-speed rotary method, for example, printed with Versa Mark ink # 1000 series, water resistance, It is possible to provide a pressure-sensitive postcard paper for ink-jet recording, which has excellent sharpness, water resistance and sharpness of full color ink # 2000 series, excellent ghost prevention, and particularly excellent water resistance and sharpness of magenta ink # 2002. .

The adhesive layer of the pressure-sensitive postcard paper for ink-jet recording of the present invention comprises a composition for an adhesive layer mainly composed of a pressure-sensitive adhesive, a fine particle filler, an ink fixing agent, and a binder.
Examples of the pressure sensitive adhesive used in the present invention include natural rubber, modified natural rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, ethylene / vinyl acetate copolymer resin, acrylate resin, vinyl chloride resin, and vinylidene chloride. A resin, a thermoplastic elastomer, or the like is used in the form of an emulsion, or a mixture of one or more thereof, and a natural rubber derivative obtained by graft polymerization of an unsaturated monomer is particularly preferable.
Specific examples of the unsaturated monomer used in the present invention include acrylonitrile, styrene, methyl methacrylate, vinylidene chloride, maleic anhydride, acrylamide, vinyl pyrrolidone, dimethyl acrylamide, and glycidyl methacrylate. Side reactions such as formation are unlikely to occur, and methyl methacrylate, styrene and acrylonitrile in which grafting reaction occurs with certainty are preferred, and methyl methacrylate is particularly preferred. The unsaturated monomer to be graft-polymerized is 10 to 40 parts by mass with respect to 100 parts by mass of the natural rubber derivative. If the amount is less than 10 parts by mass, agglomerates of natural rubber are generated in the pump feeding system during aqueous coating, and pump clogging or agglomerates are transferred to the coated surface (adhesive layer). That is, the mechanical stability is lacking. When it exceeds 40 parts by mass, the peel strength is greatly reduced.

  Specific examples of the alkylamine / epichlorohydrin polycondensate that can have a quaternization rate of 84% or more by the colloid titration method used in the present invention include dimethylamine / epichlorohydrin polycondensate, diethylamine / epichlorohydrin polycondensate, dipropylamine.・ Epichlorohydrin polycondensate, dibutylamine / epichlorohydrin polycondensate, methylethylamine / epichlorohydrin polycondensate, methylpropylamine / epichlorohydrin polycondensate, methylbutylamine / epichlorohydrin polycondensate, ethylpropylamine / epichlorohydrin polycondensate, ethylbutylamine -1 type or 2 or more types of epichlorohydrin polycondensates are contained, Especially preferably, it is a dimethylamine epichlorohydrin polycondensate.

The quaternization rate referred to in the present invention is a colloidal titration of a 1 / 400N alkylamine / epichlorohydrin polycondensate with a standard polyanion, 1 / 400N potassium potassium sulfate solution, and a cationic dye, toluidine blue 0.1% solution. As the indicator, milliequivalent / g was calculated from the titration value at the time when the color changed from blue to reddish purple.
Since the surface charge of the colloid changes depending on the pH, in the present invention, colloid equivalents of pH 4 and pH 10 are obtained, and the quaternization rate is obtained [pH 10 / pH 4 × 100], and this value is 84% or more in the present invention. use.

The number average molecular weight of the alkylamine / epichlorohydrin polycondensate used in the present invention is preferably 500 to 2000, and particularly preferably 800 to 1500.
The quaternization rate of the alkylamine / epichlorohydrin polycondensate used in the present invention by the colloid titration method is 84% or more, particularly preferably 95% or more.
If it is less than 84%, the water resistance of cyan ink # 2001 and magenta ink # 2002 in the ink # 2000 range is particularly poor.
The cationic polymer used for this invention is 5-70 mass parts with respect to 100 mass parts of pressure sensitive adhesives, Preferably it is 10-50 mass parts. If it is less than 5 parts by mass, the water resistance effect is small, and if it exceeds 70 parts by mass, no remarkable effect can be obtained, and the peel strength also decreases.

  Examples of the fine particle filler used in the present invention include talc, kaolin, calcined kaolin, acidic clay, activated clay, amorphous synthetic silica, colloidal silica, colloidal alumina, zeolite, calcium carbonate, magnesium carbonate, titanium dioxide, zinc oxide. , Aluminum hydroxide, corn starch, potato starch, wheat starch, urea formalin resin, polyethylene resin, polystyrene resin, etc. are used, and one or a mixture of two or more types is used, and particularly preferably excellent in blocking prevention and printability. Furthermore, it is amorphous synthetic silica having a fast ink absorption and corn starch, wheat starch or titanium dioxide having high opacity, which is excellent in roll stain prevention and foam processing suitability.

  The binder for the fine particle filler used in the present invention is preferably a water-soluble polymer or a hydrophobic polymer latex. Examples of the water-soluble polymer include starch, casein, soy protein, gelatin, polyvinyl alcohol and derivatives thereof. As the hydrophobic polymer latex, for example, an acrylic latex that is a copolymer of an acrylate ester and methyl methacrylate or styrene. Vinyl acetate latex, which is a copolymer of vinyl acetate and acrylate ester or maleate ester. A vinylidene chloride latex that is a copolymer of vinylidene chloride and methyl acrylate, acrylonitrile, or vinyl chloride. Examples of the styrene butadiene latex include styrene and butadiene as main constituent monomers. Polyvinyl alcohol and derivatives thereof having excellent binding power, and styrene butadiene latex are preferable.

In the present invention, an anti-degradation agent is contained to prevent air oxidation, heat and UV degradation of the pressure sensitive adhesive. Specific examples of the degradation inhibitor include 4,4′-butyldenbis (3-methyl-6-tert-butylphenol), 2,6-di-tert-butyl-4-hydroxymethylphenol, 2,2′-methylenebis ( 4-methyl-6-tert-butylphenol), 4,4'-isopropylidenebis (2-isopropylphenol) and other phenolic systems; tri (nonylphenyl) phosphate, diphenylisodecyl phosphate, trioctadecyl phosphate and other phosphorus systems; 1,3-dimethylbutyl-N-phenyl-p-phenylenediamine, N, N'-bis (1,4-dimethylpentyl) -p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, etc. 1 type or a mixture of 2 or more types That.
If desired, the composition for an adhesive layer of the present invention can achieve an intended function by appropriately mixing auxiliary agents such as an antistatic agent, a fluorescent brightening agent, a preservative, an antifoaming agent, a penetrating agent, and a coloring dye.

The pressure-sensitive postcard paper for ink jet recording of the present invention is provided on one side or both sides of a base paper using the composition for an adhesive layer of the present invention as a coating liquid. The base paper used in the present invention is composed mainly of wood pulp and an inner filler. Wood pulp includes chemical pulp such as LBKP and NBKP; mechanical pulp such as GP, PGW, RMP, TMP, CTMP, and CGP; waste paper recycled pulp such as DIP. These pulps are suitable for papermaking and coating. Adjusts the beating degree (freeness) with a beater to maintain printability.
The beating degree varies depending on the type of pulp, but is generally 150 to 500 ml [Canadian Standard Freeness (hereinafter referred to as CSF): JIS P-8121].
In order to maintain the absorption enhancement, opacity, and printability of the Cytex ink, for example, talc, calcined kaolin, calcium carbonate, titanium dioxide and the like can be mentioned as the fine particle filler for filling, and the mixing ratio is 100 parts by mass of pulp. It is 5-30 mass parts with respect to it, Preferably it is 10-20 mass parts.
In addition, various additives such as sizing agents, yield improvers, cationizing agents, paper strength enhancing agents, etc., which are conventionally known, are mixed to be acidic and neutral in a long net paper machine, circular net paper machine, twin wire paper machine, etc. To obtain an alkaline base paper.

Examples of the method for providing the adhesive layer composition of the present invention on one side of a base paper include a blade coater, an air knife coater, a curtain coater, a bar coater, a gravure coater, a roll coater, a bill blade coater, a gate roll coater, a transfer roll coater, and the like. With this coating method, an adhesive layer is provided on one side of the base paper so that the coating amount is 1.5 to 10 g / m ² (dry mass solid content), and further suitable for printer printing, color ink In order to improve printability, the surface of the adhesive layer is processed with a smoothing device such as a super calender or soft calender so that the smoothness of the surface of the adhesive layer is 20 to 40 seconds in Beck-type smoothness, and the crimped postcard paper for bi-fold inkjet recording Get.

Alternatively, the adhesive layer composition may be provided on both sides of the base paper by coating a blade coater, air knife coater, curtain coater, bar coater, gravure coater, roll coater, bill blade coater, gate roll coater, transfer roll coater, etc. Coating on one side of the base paper and then on the other side in the construction method (so that a separation balance on both sides can be obtained) with a single-side coating amount of 1.5 to 10 g / m ² (dry mass solid content) After drying, an adhesive layer is provided, and in the same manner as described above, the surface of the adhesive layer is smoothed by a smoothing device such as a super calender or soft calender so that the smoothness of the surface of the adhesive layer is 20 to 40 seconds, and is folded in three. A pressure-sensitive postcard paper for ink jet recording is obtained.

  The preferred embodiments of the present invention and the excellent effects thereof will be specifically described below with the most representative examples. In the following, all parts are parts by mass, and all% are% by mass.

Example 1
[Folding (single side coating) Preparation of base sheet for pressure-sensitive postcard for inkjet recording]
LBKP (CSF 300 ml) 100 parts Talc 20 parts 50% rosin size emulsion 3.4 parts 50% sulfuric acid band aqueous solution 5 parts 4% amphoteric polyacrylamide aqueous solution 3.8 parts After making 1% slurry of the above composition with a long paper machine 6% oxidized starch (Nihon Shokuhin Kako Ltd.: MS-3800) performed a size press so that the duplex adhesion amount 1.2 g / m ² (dry mass solids) in an aqueous solution, having a basis weight of 138 g / m ² clamshell A base paper for pressure-sensitive postcards for ink jet recording was obtained.

[Folding (single-sided coating) Preparation of pressure-sensitive postcard paper for inkjet recording]
While stirring 550 parts of the prepared water, 16 parts of a 25% caustic soda aqueous solution (mass solid content 4 parts), 50 parts of amorphous synthetic silica powder (Mizusawa Chemical Industry: Mizukasil P78D), amorphous synthetic silica powder (Mizusawa Chemical) Industrial product: Mizukasil P78F) 50 parts and wheat starch powder (Glyco Nutrition Foods product: 75A) 20 parts are gradually added and dispersed. Next, 200 parts of a 50% modified natural rubber emulsion obtained by graft polymerization of 25% of methyl methacrylate (100 parts by mass solid content), 100 parts of a 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 84% and a number average molecular weight of 2000 (Mass solid content 50 parts) 10% polyvinyl alcohol aqueous solution 100 parts (mass solid content 10 parts), 50% styrene butadiene copolymer latex 80 parts (mass solid content 40 parts), 4,4'-butyldenbis (3- After gradually adding 7.5 parts of methyl 6-tert-butylphenol) 40% dispersion (mass solid content 3 parts), it is adjusted to 25.0% solids concentration with dilution water and used for an adhesive layer for ink jet recording. A coating solution was obtained.

This adhesive layer coating solution is applied to the 138 g / m ² base paper prepared above and dried with an air knife coater so that the coating amount is 6.5 g / m ² (dry mass solid content). After providing the adhesive layer, it was processed with a soft calender so as to have a Beck smoothness of 25 to 30 seconds to obtain a crimped postcard paper for bi-fold ink jet recording.

Example 2
[Trifold (double-sided coating) Preparation of pressure-sensitive postcard for inkjet recording]
LBKP (CSF 300 ml) 90 parts NBKP (CSF 300 ml) 10 parts Talc 20 parts 50% rosin size emulsion 3.2 parts 50% sulfuric acid band aqueous solution 4 parts 4% amphoteric polyacrylamide aqueous solution 3.6 parts After making with a paper machine, size press is performed with a 6% aqueous solution of oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .: MS-3800) so that the double-sided adhesion is 1.2 g / m ² (dry mass solid content), and the basis weight is 113 g. A base paper for tri-fold pressure-bonded postcards of / m ² was obtained.

[Production of tri-fold (double-sided coating) pressure-sensitive postcard paper for inkjet recording]
One side of the 113 g / m ² base paper prepared above for the adhesive layer coating solution of Example 1 (coating amount 6.8 g / m ^{2 of} dry mass solids), and then the other side (dry mass solids) After coating and drying with an air knife coater to obtain a balance of peel strength on both sides with an air knife coater to a coating amount of 6.5 g / m ² ), a Beck smoothness is 25 to 25 with a soft calender. A tri-fold crimped postcard paper was obtained by processing for 35 seconds.

Example 3
[Production of tri-fold (double-sided coating) pressure-sensitive postcard paper for inkjet recording]
The 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 84% and a number average molecular weight of 2000 in Example 1 was converted to a 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 99% and a number average molecular weight of 300. A crimped postcard paper for tri-fold inkjet recording was obtained in the same manner as in Example 2 except that the same amount was replaced.

Example 4
[Production of tri-fold (double-sided coating) pressure-sensitive postcard paper for inkjet recording]
The 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 84% and a number average molecular weight of 2000 in Example 1 was converted to a dimethylamine / epichlorohydrin 50% aqueous solution having a quaternization ratio of 99% and a number average molecular weight of 3000. A crimped postcard paper for tri-fold inkjet recording was obtained in the same manner as in Example 2 except that the same amount was replaced.

Example 5
[Production of tri-fold (double-sided coating) pressure-sensitive postcard paper for inkjet recording]
The 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 84% and a number average molecular weight of 2000 in Example 1 was converted to a dimethylamine / epichlorohydrin 50% aqueous solution having a quaternization ratio of 99% and a number average molecular weight of 500. A crimped postcard paper for tri-fold inkjet recording was obtained in the same manner as in Example 2 except that the same amount was replaced.

Example 6
[Production of tri-fold (double-sided coating) pressure-sensitive postcard paper for inkjet recording]
The 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 84% and a number average molecular weight of 2000 in Example 1 was converted into a 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 99% and a number average molecular weight of 1100. A crimped postcard paper for tri-fold inkjet recording was obtained in the same manner as in Example 2 except that the same amount was replaced.

Comparative Example 1
[Folding (single-sided coating) Preparation of pressure-sensitive postcard paper for inkjet recording]
A crimped postcard paper for bi-fold ink jet recording was obtained in the same manner as in Example 1 except that the 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 84% and a number average molecular weight of 2000 was removed.

Comparative Example 2
[Production of tri-fold (double-sided coating) pressure-sensitive postcard paper for inkjet recording]
A tri-fold crimped postcard paper was obtained in the same manner as in Example 2 except that the aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 84% and a number average molecular weight of 2000 in Example 1 was removed.

Comparative Example 3
[Production of tri-fold (double-sided coating) pressure-sensitive postcard paper for inkjet recording]
The 50% aqueous dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 84% and a number average molecular weight of 2000 in Example 1 was converted to a 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 51% and a number average molecular weight of 1100. A crimped postcard paper for tri-fold inkjet recording was obtained in the same manner as in Example 2 except that the same amount was replaced.

Comparative Example 4
[Production of tri-fold (double-sided coating) pressure-sensitive postcard paper for inkjet recording]
The 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 84% and a number average molecular weight of 2000 in Example 1 was converted to a 50% aqueous solution of dimethylamine / epichlorohydrin polycondensate having a quaternization ratio of 80% and a number average molecular weight of 1100. A crimped postcard paper for tri-fold inkjet recording was obtained in the same manner as in Example 2 except that the same amount was replaced.

The bi-fold and tri-fold ink-jet recording postcard papers obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were measured and evaluated by the following methods.
Measurement / Evaluation Method << Peel Strength >>
[Folded (with adhesive layer on one side) pressure-sensitive postcard paper for inkjet recording]
Folded in a 23 ° C 50% RH room with the adhesive layer surface on which confidential information is printed inside in a V shape with a width of 102 mm x length of 152.5 mm, and a pressure scale on a dry sealer (PRESSLESS multi 6852T) Is set to the desired scale and crimped, and then the crimped postcard paper is cut into a size of 25 mm wide × 150 mm long, and the crimping portion is pulled by a Tensilon universal tensile tester (manufactured by Kumagaya Riken Kogyo Co., Ltd.). A T-shaped peel test was performed to measure peel strength. The pressure-sensitive postcard paper for bi-fold ink jet recording of the present invention was a sealer pressure scale 18 in Example 1 that gave a peel strength of 0.65 N / 25 mm after 10 minutes of pressure bonding.

[Tri-Fold (with adhesive layer on both sides) pressure-sensitive postcard paper for inkjet recording]
In the room at 23 ° C and 50% RH, the adhesive layer surface on which confidential information is printed should be the arrow (→) surface → N-shaped, folded in three so that it is 102mm wide x 152.5mm long. Set the pressure scale to the desired scale and perform crimping, then cut the crimped postcard paper into a size of width 25 mm x length 150 mm, and the confidential information crimping part and the other address / standard part crimping part at a pulling speed of 300 mm / min. A T-shaped peel test was conducted using a Tensilon universal tensile tester, and the peel strength was measured. The pressure-sensitive postcard paper for tri-fold ink jet recording according to the present invention has a sealer pressure scale 30 in Example 2 that provides a confidential information surface peel strength of 0.65 N / 25 mm after 10 minutes of pressure bonding.
The unit is represented by N / 25 mm, and the larger the value, the stronger the peel strength.

《Water resistance and sharpness of inkjet printed images》
After injecting Versa Mark Black Ink # 1069, Versa Mark Magenta Ink # 2002, or Versa Mark Black Ink # 2003 into the ink cartridge of an inkjet printer (Canon: BJC420J), test print pattern (characters, lines, solid) on the adhesive layer surface After 20 minutes of printing, the film was immersed in water for 30 minutes, and the decolorization degree and image clarity of the printed image after natural drying were visually determined.
○ mark: There is no color erasure and bleeding, and it is very excellent.
○ △: Slightly decolored, but no bleeding and excellent.
X mark: Discoloration and bleeding occur and are not practical.

<< Ghost in inkjet print image after crimping and peeling >>
After printing in the same way as for the water resistance and clearness evaluation of the above-mentioned printed image, adjust the pressure scale of the dry sealer immediately after crimping by adjusting it to half-fold or three-fold by the same method as the peel strength measurement sample. Crimping was performed so that the peel strength was 0.6 N / 25 mm. The ghost after 1 hour was visually evaluated.
○: There is no ghost at all and it is excellent.
Δ: Slight ghost is observed, but there is no practical problem.
X mark: There is a ghost and it is not practical.

  The above measurement / evaluation results are summarized in Table 1, Table 2, and Table 3. Table 3 shows the overall evaluation. ○ mark: Excellent. X mark: Not practical.

Claims (2)

  Under normal conditions, neither adhesiveness nor adhesiveness is shown. Adhesive layer is provided by applying a composition for pressure-sensitive adhesives, fine particle fillers, and ink fixing agents that can be peeled off under pressure. A pressure-sensitive postcard paper for ink-jet recording, wherein the ink fixing agent is an alkylamine-epichlorohydrin polycondensate having a quaternization rate of 84% or more by a colloid titration method.   2. The pressure-sensitive postcard paper for ink-jet recording according to claim 1, wherein the alkylamine / epichlorohydrin polycondensate has a number average molecular weight of 500 to 2,000.