JP2002294195A - Pressure-bonding recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a pressure-bonding recording paper sheet which is excellent in printability in offset printing when form printing and also excellent in printability with a non-impact printer. SOLUTION: This pressure-bonding recording paper sheet comprises a substrate and a pressure-sensitive adhesive layer which is formed thereon, normally doest not exhibit tackiness and adhesiveness, and exhibits releasable adhesiveness when pressed. The pressure-sensitive adhesive layer contains a natural rubber derivative prepared by grafting an unsaturated monomer onto natural rubber, 25-35 wt.% (based on the amount of the natural rubber derivative; the same applies hereunder) amorphous silica having an average particle size of 2 μm or higher but lower than 5 μm, 5-15 wt.% amorphous silica having an average particle size of 5 μm or higher but lower than 10 μm, and 0.3 wt.% or lower amorphous silica having a particle size of 50 μm or higher. The grafting is performed by using a specific unsaturated monomer. The coating weight of the pressure-sensitive adhesive layer is 3-10 g/m<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to pressure-sensitive recording paper. More specifically, the present invention relates to a pressure-sensitive recording sheet having excellent offset printability and excellent printability in a non-impact printer.
Here, the pressure-bonded recording paper refers to a recording paper having a pressure-sensitive adhesive layer that exhibits neither adhesiveness nor adhesiveness in a normal state, exhibits adhesiveness under pressure, and can be peeled off after pressure-bonding.

[0002]

2. Description of the Related Art A pressure-sensitive recording paper forms a pressure-sensitive adhesive layer made of a re-peelable pressure-sensitive adhesive on a support, which does not exhibit tackiness and adhesiveness during normal handling and exhibits adhesiveness when pressed. It is made to fold, tri-fold, or by stacking a plurality of sheets, to bond by pressure in a state where the pressure-sensitive adhesive layers face each other. It is also possible to adopt a configuration that cannot be separated. For example, two-fold, three-fold, or stacking multiple sheets, sealing by pressure bonding, mailing as a single postcard, and then peeling off the adhesive part that the recipient can peel off, When used as a peelable postcard, concealed postcard, or pressure-bonded postcard that can read recorded information, it will be possible to convey more information than ordinary postcards, and it will be known to others. The confidential communication information (PIN, membership number, billing amount, deposit balance, etc.) that you do not want to record is recorded on a peelable pressure-sensitive adhesive surface, and is mailed after being pressed and bonded, resulting in excellent confidentiality. Usage is increasing.

[0003] Here, the distribution process of the normal pressure recording paper is constituted as follows. First, a paper maker or an adhesive maker forms a pressure-sensitive adhesive layer on at least one surface of the support, which does not show tackiness or adhesiveness in a normal state, but shows adhesiveness that can be peeled off by pressing, and records the pressure. Manufacture and sell paper. Then, after a printing company performs form printing or the like on the pressure-sensitive recording paper by an offset method, or a gravure method, a data input specialist is preferably a non-impact printer, that is, a toner fixing method (electrophotography, a laser printer, etc.), or The confidential communication information is printed by various printing methods such as an ink jet method, the confidential communication information recording surfaces are adhered to each other in a releasable state using a pressure sealer, and mailed to a recipient.

As the pressure-sensitive adhesive used for such pressure-sensitive recording paper, natural rubber or a natural rubber derivative is preferably used. One of the reasons is that natural rubber derivatives have high self-adhesiveness, and when they are brought into contact with each other and pressurized, the adhesiveness is developed, but under normal conditions, both tackiness and adhesiveness are low, and so-called tackiness is low. To have.
The second reason is that grafting increases the polarity of the molecule and increases the anchoring force for hydrophilic substances. Also, simply forming a pressure-sensitive adhesive layer consisting of a natural rubber or a natural rubber derivative alone on the surface of the support easily causes blocking, lacks printing ink fixability, and is suitable for form printing and non-impact printers. Since printability is often insufficient, a pressure-sensitive adhesive layer having a releasable adhesiveness, which is usually composed of a mixture of fillers, is formed on the surface of the support to produce a pressure-sensitive recording paper. As a method of forming a pressure-sensitive adhesive layer showing the present releasable adhesive property on the surface of the support, the emulsion type is used because of the adjustment of the mixture, the workability of the pressure-sensitive adhesive layer forming step, and safety. Aqueous coating using an aqueous coating liquid comprising a natural rubber derivative and a filler.

[0005] The above-mentioned filler is used for the purpose of adjusting the surface tackiness without impairing the surface strength. In addition, printability at the time of form printing and ink fixability (hereinafter referred to as “2.
The two properties are called “incorporation”).
Alternatively, an organic pigment is added. Amorphous silica is often used as a pigment.

However, it is necessary to add a large amount of pigment in order to improve the printability such as the inking property in form printing and the printability such as stain on a preheat plate in non-impact printer printing. Since the surface strength and the pressure-sensitive adhesiveness are reduced, it is difficult to obtain good pressure-sensitive recording paper with all of the above characteristics in a well-balanced manner. Was desired.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure-sensitive recording sheet which is excellent in offset printability and excellent in printability by a non-impact printer.

[0008]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have come to invent the pressure-sensitive recording paper of the present invention. That is, the pressure-sensitive recording paper of the present invention, on at least one side of the support, adhesive in the normal state,
In a pressure-sensitive recording paper having a pressure-sensitive adhesive layer that exhibits adhesiveness that can be peeled off under pressure without showing adhesiveness, the pressure-sensitive adhesive layer is made of a natural rubber derivative grafted with at least an unsaturated monomer and amorphous silica. And a pressure-sensitive recording paper comprising two kinds of amorphous silica, wherein the amorphous silica has an average particle diameter of 2 μm or more and less than 5 μm and 5 μm or more and 10 μm or less.

The average particle diameter is 2 μm with respect to 100 parts by weight of the natural rubber derivative contained in the pressure-sensitive adhesive layer.
The addition amount of the amorphous silica having a particle size of
35 parts by weight, and the average particle size is 5 μm or more and 10
It is preferable that the addition amount of the amorphous silica having a size of not more than μm is 5 to 15 parts by weight.

[0010] More preferably, the weight ratio of the amorphous silica having a particle diameter of 50 µm or more is 0.3% or less of the whole amorphous silica.

The unsaturated monomer to be grafted to the natural rubber is more preferably at least one selected from methyl methacrylate, styrene and acrylonitrile.

[0012] The pressure-sensitive adhesive layer is 3 g / m ² or more and 10 g / m ²
m ² or less is preferable.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The contents of the present invention will be described more specifically. That is, the pressure-sensitive recording paper of the present invention is a pressure-sensitive recording paper having a pressure-sensitive adhesive layer that exhibits adhesiveness that can be peeled off by applying pressure on at least one surface of the support, which does not show adhesiveness or adhesiveness in a normal state. The pressure-sensitive adhesive layer contains at least an unsaturated monomer-grafted natural rubber derivative and amorphous silica, and the amorphous silica has an average particle size of 2 μm or more and less than 5 μm and 5 μm or more and 10 μm or less. By adopting a structure composed of various types of amorphous silica, the inking property and printing durability during form printing and printing suitability in non-impact printers are compared with the case where amorphous silica other than this configuration is used. Is also excellent,
It has become possible to obtain pressure-sensitive recording paper having a good balance of various properties.

The average particle diameter is 2 μm with respect to 100 parts by weight of the natural rubber derivative contained in the pressure-sensitive adhesive layer.
The addition amount of the amorphous silica having a particle size of
35 parts by weight, and the average particle size is 5 μm or more and 10
By setting the addition amount of the amorphous silica of not more than μm to be 5 to 15 parts by weight, the balance of the above-mentioned various properties is further improved as compared with the case where the amount is out of this range. Can be more reliably improved.

Further, when the weight ratio of the amorphous silica having a particle diameter of 50 μm or more to 0.3% or less of the entire amorphous silica, the generation of stains on the preheat plate during printing by a non-impact printer is achieved. The effect of improving the printing durability and the peel strength at the time of form printing can be further ensured while maintaining the characteristics of a small amount.

The amorphous silica used in the present invention may be any one as long as it satisfies the physical properties defined by the present invention, and a commercially available one can be suitably used.

The unsaturated monomer for grafting the natural rubber in the present invention is specifically acrylonitrile,
Examples include styrene, methyl methacrylate, vinylidene chloride, maleic anhydride, acrylamide, vinylpyrrolidone, dimethylacrylamide, and glycidyl methacrylate. Among these, it is particularly preferable to use at least one or more selected from methyl methacrylate, styrene, and acrylonitrile since side reactions such as formation of a homopolymer hardly occur and the grafting reaction proceeds reliably.

The coating amount of the pressure-sensitive adhesive layer is 3 g / m
^A preferred range is ^{2 to} 10 g / m ² . 3g / m
If it is less than ^{2, the} inking property and the peel strength at the time of form printing are significantly reduced. On the other hand, if it exceeds 10 g / m ² , the peeling strength becomes too strong and it becomes difficult to remove again. Further, the printing durability of the form is reduced, and the printability of the non-impact printer is reduced, for example, the amount of stain on the preheated plate is easily increased during printing.

The fillers used in the pressure-sensitive adhesive layer of the present invention include, for example, adhesion enhancement, control of adhesive strength, imparting of printability, enhancement of binder ability, prevention of blocking,
For the purpose of increasing the viscosity, various additives such as a tackifier, a release agent, a thermoplastic resin, a pigment, and a water-soluble polymer can be used.

Specifically, a rosin-based resin, a derivative thereof, a terpene-based resin, a coumarone-indene-based resin, a xylene-based resin, an alkylphenol-based resin, a petroleum resin, etc. are bonded to the pressure-sensitive adhesive layer as a tackifier. Can be used in combination as long as the properties, blocking resistance and heat resistance are not impaired.

Further, a release agent may be contained for controlling the adhesive force. Examples of the release agent include various paraffins, waxes, fatty acids, or derivatives thereof, higher alcohols, metal soaps, silicone resins, and the like. Can be used in a range. The minimum required adhesiveness required as pressure-sensitive recording paper means that the recording paper can be bonded by pressure using a pressure-sealer and has an adhesive force that does not peel off naturally over time.

Further, for the purpose of controlling the adhesiveness, a thermoplastic resin may be used in combination. Examples thereof include styrene, olefin, ester, urethane, isoprene, 1,2-butadiene, and chloride. Aqueous dispersion of thermoplastic elastomer such as vinyl, amide or ionomer, polyethylene resin, vinyl chloride resin, polypropylene resin, styrene resin, ABS resin, PVA
Aqueous dispersion of resin, acrylic resin, acrylonitrile-styrene resin, vinylidene chloride resin, AAS resin, ABS resin, cellulose derivative, thermoplastic polyurethane, polyvinyl butyral resin, poly-4-methylpentene-1 resin, polybutene-1 resin The pressure-sensitive recording paper can be used in a range that does not hinder the necessary minimum adhesiveness.

One or more known pigments can be used for the purpose of controlling the adhesive force and improving the printing suitability including the suitability for ink setting. For example, light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide,
Zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate,
White inorganic pigments such as colloidal silica, colloidal alumina, pseudo-boehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloysite, magnesium carbonate, magnesium hydroxide, styrene plastic pigment, acrylic plastic pigment, polyethylene, urea resin, melamine Examples thereof include resins, organic pigments such as benzoguanamine and starch particles, and if necessary, can be used together with various binders used in ordinary coating.

Specific examples of the binder include starches, hydroxymethylcellulose, methylcellulose,
Cellulose derivatives such as ethylcellulose and carboxymethylcellulose, gelatin, proteins such as casein, polyvinyl alcohol, modified polyvinyl alcohol, sodium alginate, polyvinylpyrrolidone, polyacrylamide, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylate Copolymer, alkali salt of polyacrylic acid, alkali salt of polymaleic acid, alkali salt of styrene / maleic anhydride copolymer, alkali salt of ethylene / maleic anhydride copolymer, isobutylene / maleic anhydride copolymer Water-soluble binders such as alkali salts of water-soluble binders such as polyacrylates, styrene / acrylate copolymers, and polyurethanes. Can be used alone, or two or more of them depending is the not also necessary limitation.

The pressure-sensitive adhesive layer of the present invention may further contain, as other additives, a dispersant, a flow improver, an antifoaming agent,
Antifoaming agents, penetrants, coloring dyes, coloring pigments, fluorescent whitening agents, ultraviolet absorbers, preservatives, anti-binders, water-proofing agents, wet paper strength agents, dry paper strength agents, antistatic agents, aging It is also possible to appropriately add an inhibitor or the like to express the desired function.

The pressure-sensitive recording paper of the present invention comprises a natural rubber derivative having at least one surface of a support grafted with at least an unsaturated monomer, and two types having an average particle diameter of 2 μm or more and less than 5 μm and 5 μm or more and 10 μm or less. A pressure-sensitive adhesive layer containing amorphous silica is provided. As a method of using the pressure-sensitive recording sheet of the present invention, for example, the pressure-sensitive adhesive sheet provided with the pressure-sensitive adhesive layer on one surface of a support is folded into a “V” shape and then pressed to cover the entire printed portion. (Folding postcard), or a method of concealing only a part of the print information by bending the sheet into an “L” shape and then pressing (folding postcard), a pressure-sensitive adhesive layer is provided on both sides of the support. By folding one sheet of pressure-sensitive recording paper into a “Z” shape to hide the printed portion, one side can be re-peeled, and the other side can be pressure-bonded with difficulty.
The confidential communication information is mailed in a state where the confidential communication information is completely concealed by a method such as tri-folded four-sided postcard) or a method in which both sides are re-peelable (tri-folded six-sided postcard). Since the contents of the communication can be confirmed and re-adhesion is not possible after the communication has been peeled off, the non-disclosure of the information can be used as a completely peelable concealment postcard or the like.

As the support used for the pressure-sensitive recording paper, a sheet such as paper, nonwoven fabric, synthetic paper, metal film, polyester film, or resin-coated paper, or a composite sheet obtained by laminating these can be used. Although it is possible, when considering the pressure-sensitive adhesive layer forming step and the processing step when used as confidential recording paper, it is preferable to use paper because it is characteristically suitable and economical.

The paper used in the present invention is composed mainly of wood pulp and pigment. As wood pulp, L
Chemical pulp such as BKP, NBKP, GP, PGW, R
Including mechanical pulp such as MP, TMP, CTMP, CMP, and CGP, pulp such as waste paper pulp such as DIP and synthetic pulp, and pigments used in the paper industry as needed;
Binders, sizing agents, fixing agents, retention aids, cationizing agents, paper strength agents, dyes and other additives are mixed together using at least one of them. Fourdrinier paper machines, circular net paper machines, twin wire paper machines And other various paper machines. Further, any of acidic paper, neutral paper and alkaline paper may be used. Further, as the paper support, any of high quality paper which is uncoated paper, art paper which is coated paper, coated paper, cast paper and the like can be used.

Examples of the method of coating or impregnating the pressure-sensitive adhesive layer on the support in the pressure-sensitive recording paper of the present invention include various gravure coaters, various blade coaters, roll coaters, air knife coaters, bar coaters, and the like.
Rod blade coater, U comma coater, AKKU
Coater, smoothing coater, short dwell coater, dip coater, falling curtain coater, slide coater, die coater, size press, simsizer, and other devices, as well as gravure, offset,
Printing methods such as letterpress and planographic printing can also be used on-machine or off-machine.

In the pressure-sensitive recording paper of the present invention, for the purpose of improving the strength of the pressure-sensitive adhesive layer, the support is coated or impregnated with the pressure-sensitive adhesive layer, and then the surface of the pressure-sensitive adhesive layer is calendered. I can do it. As a result, the coating layer does not fall off, the printability is remarkably improved, and the smoothness and glossiness of the surface are improved, so that effects such as extremely improved appearance as a printed matter are obtained.

As a means for calendering, a calendering machine such as a machine calender, a TG calender, a super calender, and a soft calender can be used. As the calender roll, a metal roll, a resin roll, or the like can be used. The pressure at which the calender treatment is performed and the number of passes of the calender are not limited, but are determined by the type and thickness of the support or the thickness of the pressure-sensitive adhesive layer.

[0032]

EXAMPLES The present invention will be described below in detail with reference to examples, but the contents of the present invention are not limited to the examples.
In the Examples, the number of parts is based on weight, and% is% by weight.

Example 1 100 parts by weight of a natural rubber derivative grafted with 25% of methyl methacrylate, 100 parts by weight of wheat starch, 33 parts by weight of amorphous silica having an average particle size of 2.2 μm (Mizukasil P707 manufactured by Mizusawa Chemical Industry Co., Ltd.) , Amorphous silica having an average particle diameter of 9 μm (Nip Seal LP, manufactured by Nippon Silica Kogyo Co., Ltd., 50 μm
The composition for forming a pressure-sensitive adhesive layer comprising 12 parts by weight of the above-mentioned amorphous silica (0.7%) was applied to a high-quality paper having a basis weight of 90 g / m ² using an air knife coater to obtain a solid content of 5 g / m ^2. And dried at 100 ° C. to obtain a pressure-sensitive recording paper.

Example 2 The amount of the amorphous silica having an average particle size of 2.2 μm was 25
A pressure-bonded recording sheet was obtained in the same manner as in Example 1 except that the weight part was changed.

Example 3 A pressure-sensitive recording sheet was obtained in the same manner as in Example 1 except that the amount of the amorphous silica having an average particle diameter of 9 μm was changed to 5 parts by weight.

Example 4 Amorphous silica having an average particle size of 9 μm was replaced with amorphous silica having an average particle size of 9 μm (Nip Seal NS, manufactured by Nippon Silica Kogyo Co., Ltd.).
A pressure-sensitive recording paper was obtained in the same manner as in Example 1 except that the thickness was changed to 1.5% of amorphous silica having a particle size of 0 μm or more.

Example 5 A pressure-bonded recording sheet was obtained in the same manner as in Example 1 except that the grafted unsaturated monomer was changed to styrene.

Example 6 A press-bonded recording sheet was obtained in the same manner as in Example 1 except that the unsaturated monomer to be grafted was changed to acrylonitrile.

Example 7 The mixing ratio of amorphous silica having an average particle size of 2.2 μm was 38
A pressure-bonded recording sheet was obtained in the same manner as in Example 1 except that the weight part was changed.

Example 8 The mixing ratio of amorphous silica having an average particle size of 2.2 μm was 23
A pressure-bonded recording sheet was obtained in the same manner as in Example 1 except that the weight part was changed.

Example 9 A pressure-bonded recording sheet was obtained in the same manner as in Example 1 except that the amount of the amorphous silica having an average particle diameter of 9 μm was changed to 17 parts by weight.

Example 10 A pressure-bonded recording paper was obtained in the same manner as in Example 1 except that the amount of the amorphous silica having an average particle diameter of 9 μm was changed to 3 parts by weight.

Example 11 A pressure-bonded recording paper was obtained in the same manner as in Example 1 except that the coating amount was changed to ² g / m ² .

Example 12 A pressure-sensitive recording sheet was obtained in the same manner as in Example 1 except that the coating amount was changed to 12 g / m ² .

Comparative Example 1 A pressure-sensitive recording paper was obtained in the same manner as in Example 1 except that the amount of the amorphous silica having an average particle diameter of 9 μm was changed to 0 parts by weight.

Comparative Example 2 A press-fit recording paper was obtained in the same manner as in Example 1 except that the amount of the amorphous silica having an average particle size of 2.2 μm was changed to 0 parts by weight.

Comparative Example 3 Amorphous silica having an average particle size of 2.2 μm was used.
7 μm amorphous silica (Mizukasil P6 manufactured by Mizusawa Chemical Industries, Ltd.)
A pressure-bonded recording paper was obtained in the same manner as in Example 1 except that the pressure-change recording paper was changed to 04).

Comparative Example 4 Amorphous silica having an average particle diameter of 9 μm was replaced with an average particle diameter of 12.5.
μm amorphous silica (Mizukasil P78 manufactured by Mizusawa Chemical Industry)
A pressure-bonded recording sheet was obtained in the same manner as in Example 1 except that F) was changed.

Comparative Example 5 A press-fit recording paper was obtained in the same manner as in Example 1 except that the natural rubber derivative grafted with 25% of methyl methacrylate was changed to natural rubber.

As described above, Examples 1 to 12 and Comparative Examples 1 to
Table 5 summarizes the average particle diameter of silica, the content% by weight of 50 μm or more, the content of silica by weight of 50 μm or more at the time of compounding, the graft monomer, and the coating amount of No. 5.

[0051]

[Table 1]

<< Evaluation Method >> The pressure-sensitive recording papers of Examples 1 to 12 and Comparative Examples 1 to 5 obtained as described above were evaluated by the following methods. The results of the evaluation are shown in Table 1.

[Offset Printing Suitability (Ink Filling, Printing Durability)] Two-color offset printing is performed on the coated surface of the pressure-sensitive adhesive layer under the following conditions, and perforation is performed at intervals of 6 inches continuously with printing. Folded at 12 inch intervals. Printing machine: TAIYO TOF400 4-color machine made by Taiyo Kikai Water supply method: Continuous water supply, H liquid is Dynaphant Alpha 1
Use 100 times liquid Print pattern: 130% 30% halftone dot printing on the whole surface Ink: T & K Best Cure Indigo, red (UV curing type) UV lamp: Metal halide type Use 6 kW per color for a total of 4 prints Speed: 120m / min Printing length: 6,000m

Regarding the inking property, A was obtained when the print quality and ink fixability of the printed pressure-sensitive recording paper were not inferior to those of the normal high-quality foam paper simultaneously printed, and B was obtained when the print quality was slightly inferior. The case where the quality was considerably poor was C. In actual use, any rating of A or B is acceptable.

Regarding the printing durability, the paper dust was collected by pressing Sellotape (registered trademark) against the blanket after printing.
A is a case where little paper dust is recognized, B is a case where paper dust is slightly adhered, and C is a case where paper dust is largely adhered. In actual use, any rating of A or B is acceptable.

[Preheat Plate Soil of Non-Impact Printer] 3,000 folded pressure recording papers after printing (about 90
0m), after completion of toner printing using an IBM 3800 type NIP printing machine, the state of the preheat plate was observed. A: no dirt was adhering, B: slight dirt, C: severe dirt. did. In actual use, any rating of A or B is acceptable.

[Removable Strength] A pressure-sensitive sealer (Pressle Multi 6852S manufactured by Toppan Forms) was applied to a pressure-sensitive recording paper printed by a non-impact printer.
Using T), the sheet was folded in two into a postcard size (10.5 cm × 14.9 cm) so that the re-peelable adhesive layers faced each other, and the sealer was subjected to pressure bonding with an adjustment scale of 20 (interval: 200 μm). Twenty-four hours after the pressure bonding, a T-peel test was performed according to JIS K 6854 to evaluate the re-peel strength. A when the adhesive force is 0.5 N / 25 mm or more and less than 0.8 N / 25 mm, and A when the adhesive force is 0.3 N / 25 mm or more and less than 0.5 N / 25 mm and 0.8 N / 25 mm or more and less than 1.2 N / 25 mm. B, C was less than 0.3 N / 25 mm and C was more than 1.2 N / 25 mm. In actual use, any rating of A or B is acceptable.

[0058]

[Table 2]

It is apparent from Table 2 that the pressure-sensitive recording paper having a pressure-sensitive adhesive layer on at least one surface of the support, which does not show tackiness or adhesiveness in a normal state, but exhibits adhesiveness that can be peeled off under pressure, is used in the present invention. Examples 1 to 3 which are pressure-sensitive recording papers of the invention
12 is peel strength, inking property at the time of form printing, printing durability,
In addition, the print suitability for non-impact printers is maintained at a practically acceptable level. On the other hand, as compared with Example 1, Comparative Example 1 comprising only one kind of amorphous silica having an average particle diameter of 2 μm or more and less than 5 μm or amorphous silica having an average particle diameter of 5 μm or more and 10 μm or less , And 2, the preheat plate stain and the inking property were reduced to practically problematic levels, respectively.

The other conditions were the same, and the average particle diameter was 2 μm.
Examples 8, 2, 1, and 8 in which the addition amount of the amorphous silica of not less than 5 μm is different from 23% to 38% of the natural rubber derivative.
By comparing 7 and 7, it can be seen that when the amount of the silica added is 25 to 35% of the natural rubber derivative, the balance of quality becomes the best, which is preferable. Also,
Other conditions are the same, and the average particle diameter is 5 μm or more and 10 μm.
The addition amount of the following amorphous silica is 3 of the natural rubber derivative.
By comparing Examples 10, 3, 1, and 9, which differ from 17% to 17%, it is preferable that the amount of the silica added is 5 to 15% of the natural rubber derivative because the balance of quality becomes the best. You can see that.

Comparative Example 3 using amorphous silica having an average particle diameter of 1.7 μ which is slightly smaller than the lower limit of the present invention, and an average particle diameter of 12.5 μm which is slightly larger than the upper limit of the present invention
In Comparative Example 4 using amorphous silica, the printing durability was lowered to a practically problematic level. From the above, the preferable average particle diameter of the two types of amorphous silica used is 2 μm each.
It can be seen that it is not less than 5 μm and not less than 5 μm and not more than 10 μm.

Amorphous silica having a particle size of 50 μm or more is larger than that of Example 4 in which the weight ratio of amorphous silica is more than 0.3% of the entire amorphous silica. However, Examples 1, 5, and 6 in which the weight ratio is 0.3% or less of the entire amorphous silica have a better balance of quality, so that the amorphous silica having a particle diameter of 50 μm or more is It is understood that the weight ratio is preferably 0.3% or less of the whole amorphous silica.

As compared with Examples 1, 5, and 6 using the natural rubber derivative of the present invention, Comparative Example 5 using natural rubber
The peel strength becomes too strong, and the re-peelability is lowered, and the contamination of the preheat plate is reduced to a practically problematic level. From the above, it is understood that it is preferable to use the natural rubber derivative of the present invention.

The other conditions were the same, and a comparison was made between Examples 11, 1 and 12, which differed only in the amount of the pressure-sensitive adhesive layer applied. The amount of the pressure-sensitive adhesive layer applied was in the range of 3 to 10 g / m ² . It turns out to be preferable.

[0065]

According to the present invention, there is provided a pressure-sensitive recording sheet having a pressure-sensitive adhesive layer which does not show tackiness or adhesiveness in a normal state and exhibits peelable adhesiveness under pressure on at least one surface of a support.
The pressure-sensitive adhesive layer contains at least an unsaturated monomer-grafted natural rubber derivative and amorphous silica, and the amorphous silica has an average particle diameter of 2 μm or more and less than 5 μm and 5 μm or more and 10 μm or less. By adopting a configuration consisting of different types of amorphous silica, the suitability for offset printing during form printing and the contamination of the pre-heated plate during printing with a non-impact printer are compared with the case where amorphous silica other than this configuration is used. It is possible to obtain a pressure-bonded recording sheet having a good balance of various properties and a very small reduction in other properties usually accompanied by improving the generation amount of the recording paper to a practical level.

With respect to 100 parts by weight of the natural rubber derivative contained in the pressure-sensitive adhesive layer, the average particle diameter is 2 μm or more and 5 μm or more.
A composition in which the addition amount of the amorphous silica having a particle diameter of less than μm is 25 to 35 parts by weight, and the addition amount of the amorphous silica having an average particle diameter of 5 μm or more and 10 μm or less is 5 to 15 parts by weight. By comparing with the case out of this range, it is possible to more reliably improve the printing suitability at the time of form printing and the improvement effect of the generation amount of the preheat plate stain when printing with a non-impact printer. it can.

When the weight of the amorphous silica having a particle diameter of 50 μm or more is set to 0.3% or less of the whole amorphous silica, printing by a non-impact printer can be performed.
The effect of improving the printing durability and the peel strength at the time of printing the form becomes more reliable while maintaining the characteristic that the generation amount of the preheat plate stain is small.

By using at least one selected from the group consisting of methyl methacrylate, styrene and acrylonitrile as the unsaturated monomer to be grafted to the natural rubber in the present invention, the above-mentioned various effects can be more reliably achieved.

The above-mentioned various improvement effects are obtained when the coating amount of the pressure-sensitive adhesive layer is 3
It becomes certain in the range of 10 to 10 g / m ² .

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C005 WA03 4F100 AA20A AL04A AN01A BA02 CA23A DE01A DG10B EH462 GB71 JA12A JL13A JL14A 4J004 AA01 AA05 AA18 AB01 CA02 CB02 CC02 EA04 FA01 4J040 DL0342 HA30609B

Claims (5)

[Claims] 1. A pressure-sensitive recording paper having a pressure-sensitive adhesive layer on at least one surface of a support, which does not show tackiness or adhesiveness in a normal state, but exhibits adhesiveness that can be peeled off by applying pressure.
The pressure-sensitive adhesive layer contains a natural rubber derivative grafted with at least an unsaturated monomer and amorphous silica, and the amorphous silica has an average particle diameter of 2 μm or more and less than 5 μm and 5 μm or more and 10 μm or less. Compression recording paper comprising two types of amorphous silica. 2. The amount of the amorphous silica having an average particle diameter of 2 μm or more and less than 5 μm is in the range of 25 to 35 based on 100 parts by weight of the natural rubber derivative contained in the pressure-sensitive adhesive layer.
Parts by weight, and the average particle diameter is 5 μm or more and 10 μm
2. The pressure-sensitive recording paper according to claim 1, wherein the amount of the following amorphous silica is 5 to 15 parts by weight. 3. The pressure-sensitive recording paper according to claim 1, wherein the weight ratio of the amorphous silica having a particle diameter of 50 μm or more is 0.3% or less of the whole amorphous silica. . 4. The pressure-sensitive recording paper according to claim 1, wherein the unsaturated monomer grafted to the natural rubber is at least one selected from methyl methacrylate, styrene and acrylonitrile. 5. The pressure-sensitive adhesive layer has a thickness of 3 g / m ^{2 to} 10 g.
/ M ² or less.
4. The pressure-sensitive recording paper according to item 4.