JP2001226644A - Ultraviolet hardening-type pressure sensitive adhesive and sheet for pressure-sensitive adhesion printing using the adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet hardening-type pressure sensitive adhesive easily peelable regardless of elapsed time and peeling direction after adhesion by pressurizing overlapped faces opposed to each other to adhere to each other, and to provide a sheet for pressure-sensitive adhesion printing by using the adhesive. SOLUTION: This ultraviolet hardening-type pressure sensitive adhesive where a trifunctional photopolymerizable acrylic monomer of >=80 pts. mass is compounded with both of a photopolymerizable acrylic monomer and a photopolymerizable acrylic oligomer of a total of 100 pts. mass is employed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet-curable pressure-sensitive adhesive and a pressure-sensitive adhesive printing sheet using the same, and more particularly, to an information-carrying surface formed by folding or cutting. Folding sheet,
Pressure-sensitive adhesive printing sheets such as confidential information transmission sheets such as superimposed sheets, scalable arrangement sheets, office paper sheets such as copy paper, and UV-curable pressure-sensitive sheets used for these It relates to an adhesive.

[0002]

2. Description of the Related Art Conventionally, in a printing sheet that carries information on a superimposed surface, the superposed surfaces are usually arranged in a pattern such that the superimposed surfaces are in contact with each other so as to adhere to each other. A cured layer of a pressure-sensitive adhesive is provided on the entire surface, a specific portion, or linearly. This pressure-sensitive adhesive is also referred to as a self-adhesive pressure-sensitive adhesive, and is a type in which polymers are adhered to each other by self-diffusion by applying high pressure in a state where the cured layers are in contact with each other.
Depending on the type of the composition and the degree of the pressure, permanent adhesiveness and removable adhesiveness are realized.

Conventionally, the main component of the pressure-sensitive adhesive used in this type of printing sheet generally contains an aqueous medium such as an aqueous emulsion such as an acrylic emulsion, a natural rubber latex, or a synthetic rubber latex, or a rubber latex. When a pressure-sensitive adhesive containing such an aqueous medium is applied to the surface of a substrate such as paper and dried for the formation of a cured layer, a special dryer is required or the working time is increased. In addition, it has disadvantages such as deformation of a base material such as paper and loss of information carried.

[0004]

In order to solve the problems of the conventional pressure-sensitive adhesives, the present inventors have proposed a solventless UV-curable pressure-sensitive adhesive which does not use an aqueous medium (Japanese Patent Application Laid-Open No. 10-1998). 263466, JP-A-10-26
No. 5742). However, even in the case of a printing sheet using this ultraviolet-curable pressure-sensitive adhesive, the ultraviolet-curable pressure-sensitive adhesive applied to the superposed surface is irradiated with ultraviolet rays and cured to form a cured layer. After the superposed surfaces of the pressure-sensitive adhesive printing sheet are brought into contact with each other and a high pressure is applied to bond the cured layers to each other, after a required time, the printing sheet in the bonded state is opened if necessary. In this case, the adhesive force (peeling force) between the superposed surfaces changes with time. For example, when two bonded base sheets are peeled in a 90 ° direction or a 180 ° direction, peeling occurs at the interface between the cured layers. And the base sheet is torn.

A first object of the present invention is to provide a pressure-sensitive adhesive printing sheet in which the superposed surfaces are brought into close contact with each other by applying a high pressure in a state where the superposed surfaces are in contact with each other. A second object of the present invention is to provide an ultraviolet-curable pressure-sensitive adhesive that can be easily peeled regardless of the elapsed time after bonding and the peeling direction. An object of the present invention is to provide a pressure-sensitive adhesive printing sheet using an adhesive.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the total amount of the acrylic photopolymerizable monomer and the acrylic photopolymerizable oligomer added as necessary. It has been found that the problem can be solved by using a UV-curable pressure-sensitive adhesive containing a predetermined amount or more of a trifunctional acrylic photopolymerizable monomer with respect to the amount,
The present invention has been completed.

[0007] That is, the ultraviolet-curable pressure-sensitive adhesive according to claim 1 of the present invention is applied to a superposed surface of a sheet, and forms a cured layer which is not adhered in a normal state by irradiation with ultraviolet rays. A UV-curable pressure-sensitive adhesive that makes the superposed surfaces peelably adhere to each other by applying a predetermined pressure by contacting with each other, and an acrylic photopolymerizable monomer and, if necessary, added. An acrylic photopolymerizable oligomer and a photopolymerization initiator are contained, and a trifunctional acrylic photopolymerizable monomer is contained in a total of 100 parts by mass of the acrylic photopolymerizable monomer and the acrylic photopolymerizable oligomer. It is characterized by containing 80 parts by mass or more.

A pressure-sensitive adhesive printing sheet according to a second aspect of the present invention has a cured layer of the ultraviolet-curable pressure-sensitive adhesive according to the first aspect at a predetermined portion of the superposed surface of the base sheet. It is characterized by becoming.

Therefore, in the ultraviolet-curable pressure-sensitive adhesive according to the first aspect of the present invention, the trifunctional acrylic photopolymerizable monomer can be irradiated with ultraviolet rays from a suitable ultraviolet light source such as a high-pressure mercury lamp or a metal halide lamp under appropriate conditions. When the acrylic photopolymerizable monomer itself containing a predetermined amount or more is polymerized and cured, and the acrylic photopolymerizable oligomer is added, the acrylic photopolymerizable oligomer containing the acrylic photopolymerizable monomer and the trifunctional acrylic photopolymerizable monomer is used. The copolymerization of the photopolymerizable monomer results in appropriate curing of the entire adhesive. Acrylic photopolymerizable monomer containing a predetermined amount or more of trifunctional acrylic photopolymerizable monomer with high curing speed is used, so it can be peeled off by applying strong pressure while the superposed surfaces are in contact with each other. After the bonding, when the film is peeled off as required, the film can be easily peeled regardless of the elapsed time after the bonding or the peeling direction.

In the pressure-sensitive adhesive printing sheet according to the second aspect of the present invention, when a superposed surface is brought into contact with the superposed surfaces and a strong pressure is applied to adhere the sheets together, a sufficient adhesive force can be obtained. When peeling, it can be easily peeled regardless of the elapsed time after bonding or the peeling direction.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
As the acrylic photopolymerizable monomer used in the present invention,
Specifically, for example, unsaturated carboxylic acids such as acrylic acid and methacrylic acid or esters thereof, for example, alkyl-,
Cycloalkyl-, halogenated alkyl-, alkoxyalkyl-, hydroxyalkyl-, aminoalkyl-, tetrahydrofurfuryl-, allyl-, glycidyl-, benzyl-, phenoxy-acrylate and methacrylate,

Lower alkylene glycol, acrylamide, methacrylamide or derivatives thereof, for example, acrylamide and methacrylamide mono- or di-substituted with an alkyl group or hydroxyalkyl group, diacetone acrylamide and methacrylamide, N, N'-alkylenebisacrylamide And methacrylamide. These may be used alone or in combination of two or more. Monofunctional acrylic photopolymerizable monomer, difunctional acrylic photopolymerizable monomer, trifunctional acrylic photopolymerizable monomer, Alternatively, it may be a mixture of a polyfunctional acrylic photopolymerizable monomer, but in the present invention, the total amount of the acrylic photopolymerizable monomer and the acrylic photopolymerizable oligomer added as needed as described later. It is necessary that a predetermined amount or more of the trifunctional acrylic photopolymerizable monomer is contained.

The acrylic photopolymerizable oligomer used as required in the present invention is an oligomer having an acryloyl group or a methacryloyl group at the terminal. Examples of such an oligomer include epoxy acrylate, polyester acrylate, and polyvinyl alcohol. Oligomers, polyacrylic acid-based oligomers, urethane acrylate-based oligomers, and more specifically, for example, an acrylate ester of an epoxy resin, such as diglycidyl ether diacrylate of bisphenol A, an epoxy resin, acrylic acid, and methyltetrahydrophthalic anhydride. Acrylates such as reaction products of epoxy resins and reaction products of epoxy resins with 2-hydroxyethyl acrylate;

Ring-opening copolymers of glycidyl diacrylate and phthalic anhydride, esters of methacrylic acid dimer and polyol, polyesters obtained from acrylic acid, phthalic anhydride and propylene oxide, polyethylene glycol and maleic anhydride Polyester-based oligomers such as reaction products with glycidyl methacrylate,

A reaction product of polyvinyl alcohol and N-methylolacrylamide, a polyvinyl alcohol oligomer such as a product obtained by esterifying polyvinyl alcohol with succinic anhydride and then adding glycidyl methacrylate, methyl vinyl ether-maleic anhydride Polyacrylic acid-based oligomers such as a reaction product of a copolymer and 2-hydroxyethyl acrylate or a product obtained by further reacting glycidyl methacrylate;

A urethane acrylate-based oligomer having a polyoxyalkylene segment and / or a saturated polyester segment linked via a urethane bond and having an acryloyl group or a methacryloyl group at both terminals can be given. These may be used alone or in combination of two or more. Also,
Further, it can be used in combination with an oligomer other than the acrylic photopolymerizable oligomer.

Among these, in the present invention, urethane acrylate oligomers (for example, manufactured by Nippon Crowda,
Crodamar UVU-300, UVU-310, etc.) can be preferably used.

These acrylic photopolymerizable oligomers preferably have a weight average molecular weight in the range of 2,000 to 30,000. If a material having a molecular weight smaller than this is used, it will be difficult to handle because of high tackiness and blocking will occur.On the other hand, if a material having a molecular weight larger than this is used, the pressure-sensitive adhesive property after curing will be reduced. It cannot be used for removable bonding.

In the present invention, the total of the acrylic photopolymerizable monomer and the acrylic photopolymerizable oligomer is 10
80 parts by mass of the trifunctional acrylic photopolymerizable monomer
It is important that it be contained in parts by mass or more. When the acrylic photopolymerizable oligomer is not added, the trifunctional acrylic photopolymerizable monomer may be 100 parts by mass,
If the curing rate of the trifunctional acrylic photopolymerizable monomer is less than 80 parts by mass, the adhesive force becomes too large with the lapse of time after the close contact by applying high pressure in a state where the superposed surfaces are in contact with each other. The two bonded base sheets were
When peeled in the 0 ° direction or the 180 ° direction, there is a possibility that the base sheet is broken without peeling off at the interface between the cured layers.

Specific examples of the trifunctional acrylic photopolymerizable monomer include, for example, pentaerythritol triacrylate (manufactured by Toagosei Co., Ltd., M305, viscosity: 400 to 8).
00 cps / 25 ° C., Tg 250 ° C.), trimethylolpropane triacrylate (M309, manufactured by Toagosei Co., Ltd.)
Viscosity 60 to 110 cps / 25 ° C., Tg 250 ° C.), trimethylolpropane PO-modified (n ≒ 1) triacrylate (manufactured by Toagosei Co., Ltd., M310, viscosity 60 to 110 cp)
s / 25 ° C., Tg 120 ° C.), isocyanuric acid EO-modified triacrylate (manufactured by Toagosei Co., Ltd., M315, viscosity 6)
00 to 1200 cps / 25 ° C., Tg 250 ° C.), trimethylolpropane PO-modified (n ≒ 2) triacrylate (manufactured by Toagosei Co., Ltd., M320, viscosity 70 to 170 cps)
/ 25 ° C, Tg50 ° C), trimethylolpropane EO
Modified (n @ 2) triacrylate (manufactured by Toagosei Co., Ltd., M3
50, viscosity 50-70 cps / 25 ° C.), trimethylolpropane EO-modified (n ≒ 2) triacrylate (manufactured by Toagosei Co., Ltd., M360, viscosity 65-90 cps / 25 ° C.)
Tg of 53 ° C.). Among these trifunctional acrylic photopolymerizable monomers, Tg is 50 ° C.
The above are preferred.

As the photopolymerization initiator used together with the acrylic photopolymerizable monomer and the acrylic photopolymerizable oligomer, any one of known photopolymerization initiators can be selected and used. As such a photopolymerization initiator, specifically, for example, benzoin, benzoin ethyl ether, benzoin-n-propyl ether,
Benzoin alkyl ethers such as benzoin-isopropyl ether and benzoin isobutyl-ether,
Examples thereof include 2,2-dimethoxy-2-phenylacetophenone, benzophenone, benzyl, diacetyl, diphenylsulfide, eosin, thionine, 9,10-anthraquinone, and 2-ethyl-9,10-anthraquinone. These photopolymerization initiators may be used alone or in combination of two or more.

The photopolymerization initiator is used in an amount of about 0.1 to 15 parts by mass, preferably about 1 part by mass, per 100 parts by mass of the acrylic photopolymerizable oligomer and the acrylic photopolymerizable monomer in total. It is selected in the range of from 1 to 11 parts by mass, more preferably from about 8 to 10 parts by mass.

The ultraviolet-curable pressure-sensitive adhesive of the present invention may further comprise a photopolymerization accelerator, if desired, in addition to the acrylic photopolymerizable monomer, acrylic photopolymerizable oligomer, and photopolymerization initiator. Additives commonly used in the photosensitive resin composition of, for example, a tackifier, a viscosity modifier,
An anti-aging agent, a stabilizer, a coloring agent, a fine particle filler and the like can be contained.

The pressure-sensitive adhesive printing sheet of the present invention comprises:
For example, it can be manufactured as follows. That is, according to the present invention, a predetermined base material sheet is applied to a portion opposed to each other by folding, tri-folding, cutting and overlapping, or overlapping of separate bodies by a coating means such as a gravure coater, a flexo, an air knife coater, and a bar coater. The UV curable pressure-sensitive adhesive is applied to form an adhesive layer. The application at this time may be performed over the entire surface of the substrate sheet, or may be performed only on a part of the surface. On the surface of the base sheet, necessary information may be printed in advance, or after applying an adhesive layer,
Information may be printed. At this time, when printing information using a commonly used printing machine using an ultraviolet-curable ink for printing, this printing step and the application and fixing of the ultraviolet-curable pressure-sensitive adhesive of the present invention are performed. Advantageously, they can be performed simultaneously.

The base sheet used in the present invention includes, for example, high quality paper, medium paper, rough paper, and cotton paper which are uncoated papers; art paper, coated paper, lightweight coated paper which is coated paper, and the like. Other examples include plastic laminated paper, cloth, plastic laminated cloth, plastic film, and metal foil. The basis weight of the substrate is usually 50 to 160
g / m2. In the present invention, when a synthetic plastic film such as polyethylene, polypropylene, polyethylene terephthalate, or polyvinyl chloride is used as the base sheet, the surfaces of these base materials are subjected to a surface treatment such as a mat treatment or a corona treatment. Is preferred.

The amount of the ultraviolet-curable pressure-sensitive adhesive of the present invention applied to the surface of the substrate sheet is 1 to 30 g / m ^{2 in} order to maintain the adhesiveness, peelability or transparency of the adhesive layer. ,
Preferably 3 to 20 g / m ² , more preferably 5 to 1
It is selected to be within the range of 5 g / m ² .

The pressure-sensitive adhesive printing sheet manufactured in this manner is irradiated with ultraviolet rays to cure the adhesive layer appropriately, and then the superposed surfaces are brought into contact with each other. Glue under pressure.

In the pressure-sensitive adhesive printing sheet of the present invention, information on the cured layer of the ultraviolet-curable pressure-sensitive adhesive is printed with an acrylic ultraviolet-curable ink or an acrylic resin toner. It is suitable.

First, the acrylic ultraviolet curable ink is usually a vehicle comprising an acrylic photopolymerizable oligomer, an acrylic photopolymerizable monomer, and a photopolymerization initiator, and a coloring agent such as a black pigment, carbon black and a dispersant. , A stabilizer, a matting agent, a fungicide, a viscosity modifier and the like. In this case, the acrylic photopolymerizable oligomer, acrylic photopolymerizable monomer and photopolymerization initiator include the acrylic photopolymerizable oligomer, acrylic photopolymerizable monomer and photopolymerization in the above-mentioned UV-curable pressure-sensitive adhesive. Each of the initiators can be selected from those listed as examples and used. In addition, when this ink is used, the step of applying and fixing the ultraviolet-curable pressure-sensitive adhesive and the step of printing and drying can be performed simultaneously with an ordinary printing machine.

When printing information on a cured layer of a UV-curable pressure-sensitive adhesive with a toner using a laser printer or a digital press, an acrylic resin toner is most preferable. Currently, commonly used toners include, in addition to acrylic resins, which are currently the mainstream, epoxy resins, polystyrene resins, polyester resins, and polypropylene resins as main components. All of the toners adhere to the cured layer of the UV-curable pressure-sensitive adhesive of the present invention, but, like the acrylic UV-curable ink, the toner is made of an acrylic resin similar to the cured layer. The fixability between the layer and the cured layer is enhanced, and information can be provided very well.

In the present invention, it is advantageous that the UV-curable pressure-sensitive adhesive and the UV-curable ink have compositions as similar as possible. By doing so, the fixability of the ink is improved, and the characters and designs are not blurred or peeled off.

Next, examples of the structure of the pressure-sensitive adhesive printing sheet of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to these examples. FIG. 1 is a plan view of the sheet for pressure-sensitive adhesive printing, and FIG. 2 is a cross-sectional view taken along the line XX of FIG. 1. FIG. . The configuration example shown in FIGS. 1 to 3 is a “folding postcard”, a sheet for a two-fold pressure-sensitive adhesive print in which a cured layer 4 of an ultraviolet-curable pressure-sensitive adhesive is applied to the entire overlapping surface 3. It is one. In this case, the base sheet 2 is divided into an upper sheet A and a lower sheet C by a folding perforation line Mf, and carries concealment information in a state of being folded in two as shown in FIG. Then, as shown in FIG. 1 and FIG.
UV-curable pressure-sensitive adhesive is applied to the entire overlapping surface 3 when folded, that is, to the entire one side surface of the upper sheet piece A and the lower sheet piece C, in addition to the general print 5 such as a purchase item information entry field and a company name. A cured layer 4 of the agent is provided. Note that the upper sheet A
Cuts K are provided at the corners of the above, and a step is partially generated between the upper sheet piece A and the lower sheet piece B, thereby facilitating peeling of the superposed surface after bonding.

[0033]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to these Examples without departing from the gist of the present invention. (Example 1) Trifunctional acrylate (manufactured by Toagosei Co., Ltd., Aronix M310, trimethylolpropane PO-modified (n
# 1) Triacrylate, viscosity 60 to 110 cps / 2
5 ° C., Tg 120 ° C.) or (Alonix M320, manufactured by Toagosei Co., Ltd., modified with trimethylolpropane PO (n ≒)
2) Triacrylate, viscosity 70-170 cps / 25
80 ° C., Tg 50 ° C.) 80 parts by mass, bifunctional acrylate (Alonix M225, manufactured by Toagosei Co., Ltd., polypropylene glycol diacrylate (n ア ク リ レ ー ト 7), viscosity 30 to 50 cp)
s / 25 ° C, Tg-8 ° C) or (Toa Gosei Co., Alonix M240, polypropylene glycol diacrylate (n ポ リ プ ロ ピ レ ン 4), viscosity 13-24 cps / 25 ° C, T
g 50 ° C.) 10 parts by mass, monofunctional acrylate (manufactured by Toagosei Co., Ltd., Aronix M113, nonylphenol EO-modified (n ≒ 4) acrylate, viscosity 80 to 110 cps / 2
5 ° C., Tg-20 ° C.) 10 parts by mass, 2-methyl-1 [4- (methylthio) phenyl]-as a photopolymerization initiator
A UV-curable pressure-sensitive adhesive containing 10 parts by mass of 2-morpholinopropan-1-one (Irgacure 907, manufactured by Ciba Specialty Chemicals Co., Ltd.) was prepared.

The ultraviolet-curable pressure-sensitive adhesive thus obtained was applied to a coated paper having a continuous weight of 110 kg by a wire bar.
It was applied at a rate of 0 g / m ² to form an adhesive layer. Next, the adhesive layer was exposed to light by passing through the adhesive layer side three times at about 70 m / min using a 12 kW x 2 UV irradiation device to cure the adhesive layer. 90 ° peeling (T-peeling) adhesive force immediately after production of this pressure-sensitive adhesive printing sheet and 90% after 7 days
The peel strength (T-peel) and the 180 ° peel strength were evaluated by the following methods.

Measurement method of 90 ° peeling (T-type peeling) adhesive force (A) and 180 ° peeling adhesive force (B): The obtained pressure-sensitive adhesive printing sheet was 25 mm wide and 100 m long.
m, a sample was prepared, and the two samples were overlapped with a length of 25 mm and pressed under a load of 9.8 Pa.
90 ° peeling (T-type peeling) adhesive force immediately after production was measured using Autograph AGS50 (manufactured by Shimadzu Corporation) in accordance with JIS K 6854, peeling adhesive strength test method of adhesive, and 90 ° peeling after 7 days (T-type peeling) Adhesive force (gf / 2
5mm) and 180 ° peel adhesion (gf / 25mm)
(B) is measured. Table 1 shows the measurement results.

Example 2 A UV-curable pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that the bifunctional acrylate was not used and the composition shown in Table 1 was used. Table 1 shows the results of measuring the adhesive strength (gf / 25 mm).

Example 3 A UV-curable pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that only the trifunctional acrylate was used, and the adhesive force (gf / 25) was obtained in the same manner as in Example 1.
mm) are shown in Table 1.

(Example 4) As a urethane acrylate oligomer, Kurodamer UVU3 manufactured by Nippon Coda Co., Ltd.
A UV-curable pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that 10 parts by mass of 10 was used and the composition shown in Table 1 was used, and the adhesive force (gf / 25 mm) was measured in the same manner as in Example 1. Table 1 shows the measurement results.

(Comparative Example 1) An ultraviolet-curable pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that the amount of trifunctional acrylate was 70 parts by mass, which was outside the range of the present invention. In the same manner as in Example 1, the adhesive strength (gf / 25 m
Table 1 shows the measurement results of m).

(Comparative Example 2) An ultraviolet-curable pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that the amount of trifunctional acrylate was 50 parts by mass, which was outside the range of the present invention, and was used as shown in Table 1. In the same manner as in Example 1, the adhesive strength (gf / 25 m
Table 1 shows the measurement results of m).

(Comparative Example 3) The trifunctional acrylate was set to 30 parts by mass, which was outside the scope of the present invention, and 15 parts by mass of Alonix M113 was added as a monofunctional acrylate.
Alonix M110 (paracumylphenol EO-modified (n パ ラ 1) acrylate, viscosity 110-210 cps / 25 ° C., Tg-3 as a functional acrylate)
5 ° C.) and 20 parts by mass of urethane acrylate oligomer (Clodamer UVU310, manufactured by Nippon Coda).
0 parts by mass were added, and an ultraviolet-curable pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that the other components were as shown in Table 1.
Table 1 shows the results of measuring the adhesive force (gf / 25 mm) in the same manner as in Example 1.

(Comparative Example 4) Further, a silicone acrylate-based oligomer (Klodamer UVS, manufactured by Nippon Coda Co., Ltd.)
500) was added, and a UV-curable pressure-sensitive adhesive was prepared in the same manner as in Comparative Example 3 except that the other components were as shown in Table 1 and the adhesive force (gf) was obtained in the same manner as in Example 1. / 25m
Table 1 shows the measurement results of m).

[0043]

[Table 1]

From Table 1, it can be seen that the pressure-sensitive adhesive printing sheets of Examples 1 to 4 show the adhesive strength at which the 90 ° peeling adhesive force immediately after production can be peeled off, the elapsed time after bonding, the 90 ° peeling time, and the 180 ° peeling time. ° It can be seen that the adhesive strength can be easily peeled regardless of the peeling direction such as peeling. On the other hand, the pressure-sensitive adhesive printing sheets of Comparative Examples 1 to 4 had 90
° Peeling adhesive strength indicates the peeling adhesive strength, but with the elapsed time after bonding, both the 90 ° peeling adhesive strength and the 180 ° peeling adhesive strength become too large, or one of them becomes too large, and At the interface between the cured layers, the substrate sheet was broken without peeling.

[0045]

As described above, in the ultraviolet-curable pressure-sensitive adhesive according to the first aspect, the amount of the acrylic photopolymerizable monomer and the optional amount of the acrylic photopolymerizable oligomer added as required are determined. By using a UV-curable pressure-sensitive adhesive containing a predetermined amount or more of a trifunctional acrylic-based photopolymerizable monomer, the superposed surfaces are brought into close contact with each other by applying a high pressure in a state where the superposed surfaces are in contact with each other. When peeling according to the following conditions, there is an effect that the film can be easily peeled regardless of the elapsed time after bonding and the peeling direction.

Further, in the pressure-sensitive adhesive printing sheet according to the second aspect, when the superposed surfaces are brought into close contact with each other by applying a high pressure to adhere them together, a sufficient adhesive force can be obtained, and if necessary, At the time of peeling, there is an effect that the film can be easily peeled regardless of the elapsed time after bonding and the peeling direction.

[Brief description of the drawings]

FIG. 1 is a plan view of a two-fold pressure-sensitive adhesive print sheet.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is an explanatory view of a state of superposition of the pressure-sensitive adhesive print sheet of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure-sensitive adhesive printing sheet 2 Base sheet 3 Overlapping surface 4 Cured layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C005 WA03 4D075 CA07 DA35 DB18 DC27 EA21 4J004 AA01 AA10 AA17 AB01 AB07 CA02 CA04 CA05 CA06 CA08 CB01 CB02 CC02 CC03 FA01 4J040 FA081 FA101 FA141 FA151 FA161 FA232 FA262 FA272 FA292 GA03 GA05 GA05 JB07 JB08 MA09 MB09 NA10 4L055 AG36 AG71 AG85 AH37 AH50 AJ03 BE08 BE11 GA50

Claims (2)

[Claims] 1. A cured layer which is applied to a superposed surface of a sheet and which does not adhere in a normal state by irradiation with ultraviolet rays,
By applying a predetermined pressure by contacting the superposed surfaces, an ultraviolet-curing pressure-sensitive adhesive that allows the superposed surfaces to be peelably adhered to each other, and an acrylic photopolymerizable monomer, It comprises an acrylic photopolymerizable oligomer and a photopolymerization initiator, which are added accordingly.
A UV-curable pressure-sensitive adhesive characterized in that a total of 100 parts by mass of the acrylic photopolymerizable monomer and the acrylic photopolymerizable oligomer contains 80 parts by mass or more of a trifunctional acrylic photopolymerizable monomer. Agent. 2. A pressure-sensitive adhesive printing sheet having a cured layer of the ultraviolet-curable pressure-sensitive adhesive according to claim 1 on a predetermined portion of a superposed surface of a base sheet.