JPH1150025A - Yellowing suppressing sheet for pressure-sensitive adhesive print and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheet for a pressure-sensitive print for dealing with defects of a conventional sheet for pressure-sensitive print using a radiation cure type pressure-sensitive adhesive and suppressing yellowing and to provide a method for producing the sheet. SOLUTION: In producing a sheet 1 for pressure-sensitive print provided with a cure layer of a radiation cure type pressure-sensitive adhesive which is not bonded to a fixed part of a superimposed face of a substrate sheet in a normal state but is bonded by bringing both the superimposed faces and applying a fixed pressure, the cure layer is heat-treated after irradiation with radiation so that a photopolymerization initiator containing a tertiary amine used in the cure layer and a free radical derived from the initiator are vaporized and removed and do not substantially remain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive printing sheet in which yellowing is suppressed and a method for producing the same. More specifically, a surface which is folded or cut and overlapped is used as an information carrying surface. Become a folding sheet,
Radiation-curing pressure-sensitive materials that have not been used in this type of printing sheet, such as confidential information transmission sheets such as superimposed sheets, scalable sizing sheets, and office sheets such as copy paper. The present invention relates to a pressure-sensitive adhesive printing sheet that suppresses yellowing, in which superposed surfaces are adhered to each other with an adhesive, and a method for producing the same.

[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 the pressure-sensitive adhesive is provided on the entire surface, partially or linearly. This pressure-sensitive adhesive is also referred to as a self-adhesive (Autohesion) pressure-sensitive adhesive. When a high pressure is applied in a state where the cured layers are in contact with each other, the mutual polymers adhere to each other by self-diffusion. In addition, depending on the type of the composition and the degree of 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 the pressure-sensitive adhesive containing such an aqueous medium is applied to the paper surface and dried to form a cured layer thereof, a special dryer is required, and the working time is inevitable. It has drawbacks such as deformation of the paper and loss of information carried.

In order to overcome the drawbacks of the pressure-sensitive adhesive printing sheet using such a pressure-sensitive adhesive, the applicant of the present application has proposed a pressure-sensitive adhesive printing sheet using a radiation-curable adhesive. A sheet was proposed (Japanese Patent Application No. 9-73875).

[0005] The curing reaction of the radiation-curable adhesive is initiated by irradiating the photopolymerization initiator with radiation such as UV to generate free radicals, but has a drawback that the curing reaction is inhibited by oxygen in the air. Coating and irradiation in nitrogen to avoid inhibition by oxygen,
Alternatively, oxygen inhibition is prevented by using a photopolymerization initiator having a tertiary amine group bonded thereto as a photopolymerization initiator.

[0006] However, coating in nitrogen has problems such as complicated equipment and uneconomical problems. Therefore, an amine-bonded photopolymerization initiator is usually used. The initiator has a problem of yellowing the radiation-curable adhesive.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of such a conventional pressure-sensitive adhesive printing sheet using a radiation-curable pressure-sensitive adhesive and to prevent oxygen inhibition. Another object of the present invention is to provide a pressure-sensitive adhesive printing sheet which does not cause yellowing of a cured layer even when a photopolymerization initiator containing a tertiary amine group is used.

[0008]

The present inventors have conducted various studies to prevent the cured layer of a pressure-sensitive adhesive printing sheet using a radiation-curable adhesive from yellowing. When a photopolymerization initiator containing a tertiary amine group is irradiated with radiation, the photopolymerization initiator is decomposed into an amine portion and other portions to become free radicals, and the reaction is started. It is found that residual radicals that are not bonded to the residue cause yellowing, and by heating immediately after irradiation, the unreacted photopolymerization initiator and the radical not bonded to the monomer that cause yellowing are found. Found that yellowing can be prevented by volatilizing and removing
The present invention has been accomplished based on this finding.

That is, according to the first aspect of the present invention, the bonding is performed by applying a predetermined pressure by bringing the superposed surfaces into contact with each other and not applying the predetermined pressure to the predetermined portion of the superposed surface of the base sheet in a normal state. A pressure-sensitive adhesive printing sheet provided with a cured layer of a radiation-curable pressure-sensitive adhesive, wherein the photopolymerization initiator containing a tertiary amine group used in the cured layer and radicals derived therefrom are provided. It is a pressure-sensitive adhesive printing sheet in which yellowing is suppressed, which is characterized by substantially not remaining.

According to a second aspect of the present invention, there is provided a radiation sheet which is not adhered to a predetermined portion of a superposed surface of a base sheet in a normal state, but is adhered by bringing the superposed surfaces into contact with each other and applying a predetermined pressure. When producing a pressure-sensitive adhesive printing sheet provided with a cured layer of a curable pressure-sensitive adhesive, a heat treatment is performed after irradiating radiation, whereby light containing a tertiary amine group used in the cured layer is produced. 2. The method for producing a pressure-sensitive adhesive printing sheet according to claim 1, wherein the polymerization initiator and radicals derived therefrom are volatilized and removed.

According to a third aspect of the present invention, in the method according to the second aspect, a heat treatment is performed at 80 to 150 ° C. for 1 to 30 seconds immediately after the irradiation.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The pressure-sensitive adhesive printing sheet of the present invention is constituted by providing a required pressure-sensitive adhesive layer on a superposed surface of a base sheet containing information. As the material, select any material from the materials conventionally used as the base material of the pressure-sensitive adhesive printing sheet such as art paper, machine coated paper, color lithographic paper, baryta paper, glossy paper, various synthetic papers be able to.

Next, as the radiation-curable composition constituting the pressure-sensitive adhesive layer used in the present invention, an ultraviolet ray, an electron beam,
There is no particular limitation as long as the composition can be cured by radiation such as X-rays, i-rays, and g-rays. Particularly, a photosensitive composition containing a prepolymer having an unsaturated group at a terminal and a photopolymerization initiator is preferably used. preferable. Examples of the unsaturated group bonded to the terminal of the prepolymer having an unsaturated group at the terminal include an acryloyl group, a methacryloyl group, an allyl group, and a methallyl group. Examples of the prepolymer having such an unsaturated group include an acrylate of an epoxy resin such as diglycidyl ether diacrylate of bisphenol A, a reaction product of an epoxy resin with acrylic acid and methyltetrahydrophthalic anhydride, and an epoxy resin. A reaction product of a resin and 2-hydroxyethyl acrylate, an epoxy resin-based prepolymer such as a reaction product of a diglycidyl ether of an epoxy resin and diallylamine, and a ring-opening copolymer of glycidyl diacrylate and phthalic anhydride; Unsaturated polyesters such as esters of methacrylic acid dimer and polyol, polyesters obtained from acrylic acid, phthalic anhydride and propylene oxide, and reaction products of polyethylene glycol, maleic anhydride and glycidyl methacrylate A prepolymer, a reaction product of polyvinyl alcohol with N-methylolacrylamide, a polyvinyl alcohol-based prepolymer such as one obtained by esterifying polyvinyl alcohol with succinic anhydride and then adding glycidyl methacrylate; Polyamide-based prepolymers such as prepolymers obtained by reacting p, p'-diaminodiphenyl with diallyl ester of anhydride, reaction products of ethylene-maleic anhydride copolymer with allylamine, methyl vinyl ether A polyacrylic acid or maleic acid copolymer prepolymer such as a reaction product of a maleic anhydride copolymer and 2-hydroxyethyl acrylate or a product obtained by further reacting glycidyl methacrylate with the reaction product;

In addition, a urethane prepolymer 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, or a compound represented by the general formula (1): Rubber based prepolymers such as terminal acrylic modified isoprene rubber or butadiene rubber are also preferred prepolymers.

[0015]

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These prepolymers suitably have a weight average molecular weight in the range of 2,000 to 30,000. If a material having a smaller molecular weight than this is used, it will be difficult to handle because stickiness will be large and blocking will occur.
Further, when a resin having a molecular weight larger than this is used, the pressure-sensitive adhesive property after curing is reduced, and it is difficult to peel off after bonding once, so that it cannot be used for re-peelable bonding.

Next, photopolymerizable monomers used in combination with a prepolymer having a terminal unsaturated group include:
It can be arbitrarily selected from the photopolymerizable monomers used in combination with the prepolymer in the usual photosensitive resin composition.

Examples of such a monomer include unsaturated carboxylic acids such as acrylic acid and methacrylic acid and esters thereof such as alkyl-, cycloalkyl-, halogenated alkyl-, alkoxyalkyl-, hydroxyalkyl- and aminoalkyl-. , Tetrahydrofurfuryl-, allyl-, glycidyl-, benzyl-, phenoxy-acrylate and methacrylate, alkylene glycol, polyoxyalkylene glycol mono- or diacrylate and methacrylate, trimethylolpropane triacrylate and methacrylate, pentaerythritol tetraacrylate and Such as methacrylate,
Acrylamide, methacrylamide or derivatives thereof, for example, acrylamide and methacrylamide mono- or di-substituted with an alkyl group or a hydroxyalkyl group, diacetone acrylamide and methacrylamide, N,
Allyl compounds such as N′-alkylenebisacrylamide and methacrylamide, for example, allyl alcohol, allyl isocyanate, diallyl phthalate, triallyl isocyanurate, maleic acid, maleic anhydride,
Other unsaturated compounds such as fumaric acid or esters thereof, for example, alkyl or alkyl halides, mono- or dimaleates of alkoxyalkyl and fumarate, such as styrene, vinyltoluene, divinylbenzene, N-vinylcarbazole, and N-vinylpyrrolidone are used. Can be

In applications where curing shrinkage is an obstacle, examples of the monomer include isobornyl acrylate or methacrylate, norbornyl acrylate or methacrylate, dicyclopentenoxyethyl acrylate or methacrylate, and dicyclopenteno. Acrylate or methacrylate of diethylene glycol dicyclopentenyl monoether, such as xypropyl acrylate or methacrylate, acrylate or methacrylate of polyoxyethylene or polypropylene glycol dicyclopentenyl monoether, such as dicyclopentenyl cinnamate, Such as cyclopentenoxyethyl cinnamate, dicyclopentenoxyethyl monofumarate or difumarate,
3,9-bis (1,1-bismethyl-2-oxyethyl) -spiro [5,5] undecane, 3,9-bis (1,1-bismethyl-2-oxyethyl) -2,4
8,10-tetraoxaspiro [5,5] undecane,
3,9-bis (2-oxyethyl) -spiro [5,5]
Undecane, 3,9-bis (2-oxyethyl) -2,
Mono-, diacrylate or mono-, dimethacrylate such as 4,8,10-tetraoxaspiro [5,5] undecane, or mono-, diacrylate of ethylene oxide or propylene oxide addition polymer of these spiro glycols; Or mono-, dimethacrylate, or methyl ether of the monoacrylate or methacrylate, 1-azabicyclo [2,2,2]-
Dicyclopentadienyl acrylate or methacrylate, dicyclopentadienyloxyethyl acrylate, such as 3-octenyl acrylate or methacrylate, bicyclo [2,2,1] -5-heptene-2,3-dicarboxyl monoallyl ester, Methacrylate,
Dihydrodicyclopentadienyl acrylate or methacrylate can be used.

These photopolymerizable monomers may be used alone or in combination of two or more. The amount to be used is selected within 2 times or less, preferably in the range of 0.5 to 1.5 times, based on the weight of the prepolymer having a terminal unsaturated group.

In the present invention, the photopolymerization initiator used together with the above-mentioned prepolymer and photopolymerizable monomer may be any one selected from photopolymerization initiators containing a tertiary amine group. Can be. The photopolymerization initiator containing a tertiary amine group may be a photopolymerization initiator having a tertiary amine group bonded thereto, or a compound having a tertiary amine group mixed with a known photopolymerization initiator. A photopolymerization initiator may be used, and further, a mixture obtained by adding a known photopolymerization initiator to a photopolymerization initiator to which these tertiary amine groups are bonded in a range not causing inhibition by oxygen, preferably And a mixture obtained by adding about 30% by weight or less of a known photopolymerization initiator based on the mixture to a photopolymerization initiator having a tertiary amine group bonded thereto.

As the photopolymerization initiator having such a tertiary amine group, specifically, for example, 2-benzyl-2-dimethylamino-1- (4-morphoform represented by the formula (1) (Linophenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl] represented by formula (2)
-2-monforinopropanone-1 and the like.

Examples of the compound having a tertiary amine group which can be used by adding to a known photopolymerization initiator include, specifically,
For example, triethylamine, triallylamine, tri-n
Octylamine, triethanolamine, n-methyldiethanolamine represented by the formula (3), 4-dimethylaminoisoamylbenzoate [manufactured by Nippon Kayaku Co., Ltd .;
AYACURE DMBI], 4- represented by the formula (4)
Dimethylaminoethyl benzoate [Nippon Kayaku Co., Ltd.
KAYACURE EPA]. Among these compounds having a tertiary amine group, 4-dimethylaminoisoamyl benzoate [Nippon Kayaku Co., Ltd.], which has a low odor, excellent storage stability, and other properties.
KAYACURE DMBI], 4-dimethylaminoethylbenzoate [KAYAC, manufactured by Nippon Kayaku Co., Ltd.]
URE EPA] can be preferably used.

Known photopolymerization initiators include, for example, benzoin, benzoin ethyl ether, benzoin-n
Benzoin alkyl ethers such as -propyl ether, benzoin-isopropyl ether, benzoin isobutyl-ether, 2,2-dimethoxy-2-phenylacetophenone, benzophenone, benzyl, diacetyl, diphenylsulfide, eosine, thionin,
9,10-anthraquinone, 2-ethyl-9,10-anthraquinone and the like.

[0025]

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[0026]

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[0027]

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[0028]

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These photopolymerization initiators containing a tertiary amine group may be used alone or in combination of two or more. The content is usually per 100 parts by weight of the total amount of the prepolymer and the photopolymerizable monomer,
It is selected in the range of 0.1 to 10 parts by weight.

The radiation-curable pressure-sensitive adhesive used in the present invention may be used, if desired, in order to prevent the adhesive strength from increasing over time after lamination to prevent the peeling from becoming difficult or to prevent blocking. A particulate filler can be included. As such a fine particle filler, one having a small affinity for the above-mentioned three components and having a regular particle shape should be used because it is necessary to prevent the adhesive layer from impairing the transparency. Good.

Examples of such a material include various starches, synthetic zeolites, fine spherical acrylic resin, fine spherical methacrylic resin, fine spherical polyethylene, spherical alumina, glass powder, shirasu balloon, activated clay, and the like. These fillers may be used alone or 2
It may be used in combination of more than one kind. However, silica, titanium oxide, zinc oxide, and the like, which have been conventionally used as a filler in this type of adhesive composition, have an irregular particle shape, so that the adhesive layer promotes the irregular reflection of light and is transparent. However, it is preferable not to add them, but when they are added, it is preferable that the addition amount is 10% by weight or less. In addition, these fine particle fillers have an average particle diameter of 1 to 20 μm, preferably 2 to 5 μm.
Those in the range of μm are preferred.

When this fine particle filler is contained,
It is necessary to select the compounding ratio appropriately. If the compounding amount of the fine particle filler is too small, the blocking resistance is reduced, and the adhesive strength is too strong to be easily peeled off,
On the other hand, if the amount is too large, the adhesive strength becomes too low, and sufficient tackiness is not exhibited. Therefore, the mixing ratio of the fine particle filler is 100 to 300 parts by weight, preferably 130 to 250 parts by weight, more preferably 150 to 20 parts by weight, when the total amount of the radiation-curable pressure-sensitive adhesive is 100 parts by weight.
It is better to select within the range of 0 parts by weight.

The photosensitive composition constituting the radiation-curable pressure-sensitive adhesive layer in the present invention may further contain, if desired, additives commonly used in general photosensitive resin compositions, in addition to the above four components. Components such as a thermal polymerization inhibitor, a tackifier, a viscosity modifier, an antioxidant, a stabilizer, a colorant, and a fine particle filler can be contained.

Examples of the thermal polymerization inhibitor include hydroquinone, mono-tert-butylhydroquinone, benzoquinone,
2,5-diphenyl-p-benzoquinone, picric acid,
Examples thereof include di-p-fluorophenylamine, di-p-methoxyphenol, and 2,6-ditert-butyl-p-cresol. These thermal polymerization inhibitors are for preventing a thermal polymerization reaction. Therefore, the content of the thermal polymerization inhibitor is usually in the range of 0.01 to 5 parts by weight per 100 parts by weight of the resin base. Is chosen.

In the present invention, the radiation-curable mold is not adhered to a predetermined portion of the superposed surface of the base sheet in a normal state, but is adhered by bringing the superposed surfaces into contact with each other and applying a predetermined pressure. It is important to provide a cured layer of pressure-sensitive adhesive and heat-treat it after radiation to volatilize and remove unreacted photopolymerization initiators and radicals not bonded to monomers that cause yellowing. . By such a heat treatment, a sheet for pressure-sensitive adhesive printing in which yellowing is suppressed can be obtained.

The conditions for the heat treatment are not particularly limited since they differ depending on the kind of the radiation-curable pressure-sensitive adhesive. However, it is usually preferable to heat-treat at 80 to 150 ° C. for 1 to 30 seconds immediately after the irradiation. If the temperature is lower than 80 ° C. and the time is shorter than 1 second, the unreacted photopolymerization initiator and the radical not bonded to the monomer may not be sufficiently removed by volatilization.
Heat treatment at a temperature exceeding 50 ° C. for more than 30 seconds may cause yellowing or brittleness depending on the paper of the base sheet.

The pressure-sensitive adhesive printing sheet according to the present invention can be produced, for example, as follows.
That is, a predetermined base sheet is folded in two, three,
The above-mentioned radiation-curable pressure-sensitive adhesive is applied to the portions facing each other by cutting and overlapping, or overlapping each other with a gravure coater, flexo, air knife coater, bar coater, or the like, and then drying. To form an adhesive layer. The application at this time may be performed over the entire surface of the base sheet, or may be performed only on a part of the surface. On the surface of this base sheet,
Necessary information may be printed in advance, or the information may be printed after an adhesive layer is applied. On this occasion,
When printing information with a commonly used printing machine using UV-curable ink for printing, this printing process and the application and fixing of the radiation-curable pressure-sensitive adhesive can be performed simultaneously. It is advantageous.

In the present invention, when a synthetic film of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, or the like is used as the base sheet, it is preferable that the surface of the base sheet be subjected to a surface treatment such as a mat treatment or a corona treatment. . The amount of the adhesive applied to the base sheet surface is 1 to 30 g / m ² , preferably 3 to maintain the adhesiveness, peelability or transparency of the adhesive layer.
-20 g / m ² , more preferably 5-15 g / m ² .

The sheet for pressure-sensitive adhesive printing thus manufactured is irradiated with radiation such as ultraviolet rays, electron beams, X-rays, i-rays, and g-rays to cure the adhesive layer appropriately. Heat treatment is performed, for example, immediately after the irradiation.
Heat treatment is carried out at 150 ° C. for 1 to 30 seconds, and the heat-treated and cured adhesive layers on the respective surfaces are superimposed and adhered under a pressure of about 1 to 100 kg / cm ² by, for example, a pressure roller.

The permanent adhesion and removability of the cured layer of the radiation-curable pressure-sensitive adhesive in the present invention are determined by the types of the prepolymer having an unsaturated group at the end and the photopolymerizable monomer, It can be adjusted by changing the number of functional groups of the photopolymerizable monomer, the roller pressure at the time of adhesion, and the like. In general, as the number of functional groups of the photopolymerizable monomer increases, the bonding surface becomes harder and the bonding strength decreases, and as the roller pressure during bonding increases, the bonding strength increases.

Next, a configuration example of the pressure-sensitive adhesive printing sheet of the present invention will be described in detail with reference to the accompanying drawings.
Here, FIG. 1 is a plan view of a three-fold pressure-sensitive adhesive printing sheet in which a cured layer of a radiation-curable adhesive is applied linearly, which is a first configuration example, and FIG. 3 is a back view of the pressure-sensitive adhesive printing sheet of FIG. 3, FIG.
FIG. 5 is a plan view of a cut and overlap pressure-sensitive adhesive printing sheet in which a cured layer of a radiation-curable adhesive is partially applied as a second configuration example, and FIG. 5 is a cross-sectional view taken along line XX of FIG. FIG. 6 is an explanatory view of a state of superposition of the pressure-sensitive adhesive print sheet of FIG. 4, and FIG. 7 is a third configuration example in which a cured layer of a radiation-curable adhesive is applied to the entire superposed surface. FIG. 8 is a plan view of the sheet for pressure-sensitive adhesive printing with two folds, and FIG.
FIG. 9 is a cross-sectional view of the pressure-sensitive adhesive print sheet of FIG. 7, and FIG. 10 is a fourth configuration example.
FIG. 11 is a plan view of a three-fold pressure-sensitive adhesive printing sheet in which a cured layer of a radiation-curable adhesive is applied to the entire superposed surface. FIG. 11 is a rear view of the pressure-sensitive adhesive printing sheet of FIG. FIG. 13 is an explanatory view of a superposed state of the pressure-sensitive adhesive print sheet of FIG. 10, and FIG. 13 is a fifth configuration example.
FIG. 14 is a plan view of a three-fold pressure-sensitive adhesive printing sheet in which a cured layer of a radiation-curable adhesive having re-peelable adhesive properties and permanent adhesive properties is applied to each of the superposed surfaces.
3 is a rear view of the pressure-sensitive adhesive print sheet, FIG. 15 is a diagram illustrating the state of superposition of the pressure-sensitive adhesive print sheet of FIG. 13, and FIG. 16 is a diagram illustrating various means for facilitating peeling of the superposed surface after bonding. FIG. 17 is an explanatory view showing a method of adjusting the adhesive strength of a cured layer of a radiation-curable adhesive using an ink film.

First, the first configuration example shown in FIG. 1 to FIG. 3 is a three-folded envelope in which a cured layer 4 of a radiation-curable adhesive is applied in a linear manner and is configured as a “three-fold envelope”. This is a pressure-sensitive adhesive printing sheet 1. This is the base sheet 2
By two folding sewing lines Mf, Mf.
It is divided into a middle sheet B and a lower sheet C, and carries the concealment information in a state where it is folded in a Z-shape as shown in FIG. As shown in FIGS. 1 and 2, the base sheet 2
When a general print 5 such as a postal code entry field, a variable information entry field, a description, etc. is applied to the front and back surfaces, and the peripheral portion which becomes the overlapping surface 3 when folded into a Z-shape, The cured layer 4 of the radiation-curable adhesive is linearly applied in a pattern such that the cured layer 4 is in contact with. In addition, the cured layer 4 of the radiation-curable adhesive in the present configuration example may be either a permanent adhesive or a re-peelable adhesive. In the case of the re-peelable adhesive, the cured layer 4 along the linear cured layer 4 in the figure is used. No perforation line is required.

The second configuration example shown in FIGS. 4 to 6 is a cut-over pressure-sensitive adhesive print formed as a “cut-over slip” and partially provided with a cured layer 4 of a radiation-curable adhesive. Sheet 1. This is because the base sheet 2 is divided by the cutting perforation line Mc into an upper sheet A as a "delivery note" and a lower sheet C as a "receipt", and as shown in FIG. Is carried. Then, as shown in FIG. 4 and FIG.
When the general print 5 such as an article information entry field and a company name is applied to the surface of the sheet, the folded surface 3 when folded, that is, the back side of the upper sheet A and the surface of the lower sheet C when folded. A cured layer 4 of a radiation-curable adhesive is applied in the form of a strip that is in contact with each other. In addition, the cured layer 4 of the radiation-curable adhesive in the present configuration example may be either a permanent adhesive or a removable adhesive. In the case of the removable adhesive, along the strip-shaped cured layer 4 in the figure. No perforation line is required.

The third configuration example shown in FIGS. 7 to 9 is a "folding postcard", which is a two-fold pressure-sensitive adhesive in which a cured layer 4 of a radiation-curable adhesive is applied to the entire overlapping surface 3. It is a sheet 1 for sexual printing. This is because the upper sheet A and the lower sheet C are folded by the folding perforation line Mf.
And concealed information is carried in a state of being folded in two as shown in FIG. Then, as shown in FIGS. 7 and 9, a general print 5 such as a postal code entry field, a purchase information entry field or a company name is applied to the front and back surfaces of the base sheet 2, and the overlapping surface 3 when folded. A cured layer 4 of a radiation-curable adhesive is applied to the entire surface, that is, the entire surface of one side surface of the upper paper sheet A and the lower paper sheet C. In addition, since the cured layer 4 of the radiation-curable adhesive in the present configuration example has re-peeling adhesiveness, a cut K is provided at a corner of the upper paper piece A, and a partial step is formed between the upper paper piece A and the lower paper piece B. And facilitates peeling of the superposed surface after bonding. As shown in FIG. 16, such a means for easy peeling may be, as shown in FIG. 16, (a) a step formed by making a cut K at the corner of the overlapping surface, or (b) forming a step on the overlapping surface. A method such as providing a step by making a cut K in the side, or (C) providing a step by extending a flap piece F on one of the superposed surfaces can be adopted.

The fourth configuration example shown in FIG. 10 to FIG. 12 is a three-fold pressure-sensitive adhesive in which a cured layer 4 of a radiation-curable adhesive is applied to the entire superposed surface 3 configured as a “concealment postcard”. It is a sheet 1 for sexual printing. This is a state in which the base sheet 2 is divided into an upper sheet piece A, a middle sheet piece B, and a lower sheet piece C by two folding perforation lines Mf, Mf, and as shown in FIG. Carry concealment information. Then, as shown in FIG. 10 and FIG.
A general print 5 such as a variable information entry column and a description is provided, and a cured layer 4 of a radiation-curable adhesive is provided on the entire superposed surface 3 when folded into a Z-shape.

The fifth configuration example shown in FIGS. 13 and 14 is such that the cured layer 4 of the radiation-curable adhesive having permanent adhesion and removable adhesion, which is constituted as a “concealment postcard”, is superposed on both sides. The tri-fold pressure-sensitive adhesive printing sheet 1 applied to the surface 4. This is a state in which the base sheet 2 is divided into an upper paper piece A, a middle paper piece B, and a lower paper piece C by two folding perforation lines Mf, Mf, and as shown in FIG. Carry concealment information. Then, as shown in FIG. 10 and FIG. 12, a general print 5 such as a zip code entry field, a variable information entry field, an explanatory note, etc. is given on the front and back surfaces of the base sheet 2, and Z
When folded in the shape of a letter, the cured layer 4 of the radiation-curable adhesive having re-peeling adhesive is applied to the entire surface of the superposed surface 3 of the inner paper piece B and the lower paper piece C, and the upper paper piece A and the middle paper A cured layer 4 of a permanent adhesive radiation-curable adhesive is applied to the entire superposed surface 3 of the paper piece B.

The pressure-sensitive adhesive printing sheet of the present invention comprises:
This also includes the configuration in which such a permanent adhesive portion and a removable adhesive portion are present on the same base sheet. Combining radiation-curable adhesives with different prescriptions, or partially changing the degree of pressure causes permanent adhesion. And a re-peeling-bonding part. In order to adjust the adhesiveness of the cured layer of the radiation-curable adhesive, the ink layer 6 may be partially provided on the cured layer 4 of the radiation-curable adhesive as shown in FIG.

[0048]

Next, the present invention will be described in more detail by way of examples. In addition, the degree of yellowing of the pressure-sensitive adhesive print sheet in each example was evaluated according to the following evaluation criteria by measuring whiteness using a photobolt reflectometer manufactured by Toyo Seiki Seisaku-sho, Ltd. For example, the whiteness of high quality paper is about 82, the whiteness of coated paper is about 79, and the whiteness is higher when the whiteness is higher. Evaluation criteria; whiteness 70 or less: considerable yellowness x whiteness 70.1 to 72.0: slightly yellow; whiteness 72.1 to 74.0: almost no yellow appearance o whiteness 74 or more: quite colorless ◎

Example 1 Acrylic-terminated polybutadiene prepolymer (manufactured by Nippon Soda Co., Ltd., product name TE)
A-1000) Triacrylate of propylene oxide adduct of trimethylol (n ≒ 2) as a photopolymerizable monomer in 60 parts by weight (product name M-3, manufactured by Toagosei Co., Ltd.)
20) 40 parts by weight were added, and a photopolymerization initiator (trade name “Irgacure” 907, manufactured by Nippon Ciba Geigy Co., Ltd.) was added to the mixture at a ratio of 5% by weight. The adhesive composition thus obtained was applied to a coated paper having a continuous weight of 110 kg by a wire bar at a rate of 10 g / cm ² , and then subjected to an exposure treatment using an ultraviolet irradiation device manufactured by I-Graph Fix Co., Ltd. After a few seconds, heat treatment was performed at 120 ° C. for 10 seconds using a fine oven manufactured by Yamato Scientific Co., Ltd. Thus, a pressure-sensitive adhesive printing sheet having a colorless, transparent and glossy adhesive layer was produced. Table 1 shows the results of evaluation of the degree of yellowing including the case where no heat treatment was performed.

Example 2 As a photopolymerizable monomer, triacrylate of propylene oxide adduct of trimethylol (n ≒ 2) (product name: M-3, manufactured by Toagosei Co., Ltd.)
20) 20 parts by weight and 2-ethylhexyl carbitol acrylate (product name: M-120, manufactured by Toagosei Co., Ltd.)
A pressure-sensitive adhesive printing sheet was produced in the same manner as in Example 1 except that a mixture with 20 parts by weight was used. Table 1 shows the results of evaluating the degree of yellowing in the same manner as in Example 1 including the case where no heat treatment was performed. Further, a pressure-sensitive adhesive print sheet was prepared in the same manner as in Example 1 using the above-mentioned Nippon Ciba-Geigy Co., Ltd., registered trademark "Irgacure" 907 and Nippon Ciba-Geigy Co., Ltd., registered trademark "Irgacure" 369, respectively. Table 2 shows the results of evaluating the degree of yellowing in the same manner as in Example 1 for the case where no heat treatment was carried out and the case where the heat treatment was performed for 10 seconds while changing the temperature of the heat treatment within the range of 60 to 120 ° C. Shown in

Example 3 The same procedure as in Example 1 was carried out except that a mixture of 20 parts by weight of trimethylolpropane triacrylate and 20 parts by weight of 1,6-hexanediol diacrylate was used as the photopolymerizable monomer. A pressure-sensitive adhesive printing sheet was manufactured. Table 1 shows the results of evaluating the degree of yellowing in the same manner as in Example 1 including the case where no heat treatment was performed.

Example 4 To 50 parts by weight of an acrylic terminal-modified polybutadiene-based prepolymer as used in Example 1, 35 parts by weight of trimethylolpropane triacrylate and 1,6-hexanediol as photopolymerizable monomers A pressure-sensitive adhesive printing sheet was produced in the same manner as in Example 1, except that 15 parts by weight of diacrylate was added, and a composition in which 5% by weight of the same photopolymerization initiator as in Example 1 was added to this mixture. Table 1 shows the results of evaluating the degree of yellowing in the same manner as in Example 1 including the case where no heat treatment was performed.

Example 5 As a photopolymerizable monomer, a triacrylate of a propylene oxide adduct of trimethylol (n ≒ 2) (product name: M-3, manufactured by Toagosei Co., Ltd.)
20) 20 parts by weight and 2-ethylhexyl carbitol acrylate (product name: M-120, manufactured by Toagosei Co., Ltd.)
A pressure-sensitive adhesive printing sheet was produced in the same manner as in Example 4, except that a mixture of 15 parts by weight and 15 parts by weight of 1,6-hexanediol diacrylate was used. Table 1 shows the results of evaluating the degree of yellowing in the same manner as in Example 1 including the case where no heat treatment was performed.

Example 6 An acrylic-modified urethane prepolymer (product name: UV-3000B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used as a prepolymer in an amount of 60 parts by weight, and the viscosity was adjusted with 20 parts by weight of isopropyl alcohol. A pressure-sensitive adhesive print sheet was produced in the same manner as in Example 1. Table 1 shows the results of evaluating the degree of yellowing in the same manner as in Example 1 including the case where no heat treatment was performed.

(Example 7) An acrylic-modified urethane prepolymer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name: UV-3000B) was used as a prepolymer, and the viscosity was adjusted by adding 20 parts by weight of isopropyl alcohol. Produced a pressure-sensitive adhesive print sheet in the same manner as in Example 3. Table 1 shows the results of evaluating the degree of yellowing in the same manner as in Example 1 including the case where no heat treatment was performed.

Example 8 40 parts by weight of a modified urethane prepolymer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name UV-3000B) was used as a prepolymer, and a propylene oxide adduct of trimethylol ( n ≒ 2) pressure-sensitive adhesiveness in the same manner as in Example 6 except that a mixture of 40 parts by weight of triacrylate (manufactured by Toagosei Co., Ltd., product name: M-320) and 20 parts by weight of tripropylene glycol diacrylate was used. A sheet for printing was manufactured. Table 1 shows the results of evaluating the degree of yellowing in the same manner as in Example 1 including the case where no heat treatment was performed.

Example 9 As photopolymerizable monomers, 20 parts by weight of trimethylolpropane triacrylate, 20 parts by weight of tripropylene glycol diacrylate, and 2
A pressure-sensitive adhesive printing sheet was produced in the same manner as in Example 8, except that a mixture with 20 parts by weight of -ethylhexyl carbitol acrylate was used. Table 1 shows the results of evaluating the degree of yellowing in the same manner as in Example 1 including the case where no heat treatment was performed.

[0058]

[Table 1]

[0059]

[Table 2] From Table 1, it can be seen that, in Examples 1 to 9, heating immediately after UV irradiation does not cause yellowing. From Table 2, U
It can be seen that yellowing is suppressed or not yellowed by heat treatment at 80 to 120 ° C. immediately after V irradiation.

[0060]

The yellowing of the pressure-sensitive adhesive printing sheet of the present invention can be easily suppressed by heating after irradiation.

[Brief description of the drawings]

FIG. 1 is a plan view of a three-fold pressure-sensitive adhesive printing sheet according to an example of the present invention.

FIG. 2 is a rear view of the pressure-sensitive adhesive print sheet of FIG. 1;

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

FIG. 4 is a plan view of a pressure-sensitive adhesive printing sheet of another example different from FIG. 1 of the present invention.

FIG. 5 is a sectional view taken along line XX of FIG. 4;

6 is an explanatory view of a state of superposition of the pressure-sensitive adhesive print sheet of FIG. 4;

FIG. 7 is a plan view of a two-fold pressure-sensitive adhesive printing sheet according to the present invention, in which a cured layer of a radiation-curable adhesive is applied to the entire superposed surface of another example different from FIGS. 1 and 4; .

FIG. 8 is a sectional view taken along line XX of FIG. 7;

FIG. 9 is an explanatory view of a state of superposition of the pressure-sensitive adhesive print sheet of FIG. 7;

FIG. 10 is a plan view of a tri-fold pressure-sensitive adhesive print sheet of another example different from FIGS. 1, 4 and 7 of the present invention.

FIG. 11 is a rear view of the pressure-sensitive adhesive print sheet of FIG. 10;

FIG. 12 is an explanatory view of a state in which the pressure-sensitive adhesive print sheets of FIG. 10 are overlapped.

FIG. 13 is a plan view of a tri-fold pressure-sensitive adhesive print sheet of another example different from FIGS. 1, 4, 7, and 10 of the present invention.

14 is a back view of the pressure-sensitive adhesive print sheet of FIG.

15 is an explanatory view of a state of superposition of the pressure-sensitive adhesive print sheet of FIG. 13;

FIG. 16 is an explanatory diagram of various means for facilitating separation of a superposed surface after bonding.

FIG. 17 is an explanatory view showing a method of adjusting the adhesive strength of a cured layer of a radiation-curable adhesive using an ink film.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pressure-sensitive adhesive printing sheet 2 base sheet 3 overlapping surface 4 cured layer of radiation-curable adhesive 5 general printing portion A top paper piece B middle paper piece C bottom paper piece Mc Cutting perforation line Mf Folding perforation line

Claims (3)

[Claims] 1. A method according to claim 1, further comprising the step of:
A pressure-sensitive adhesive printing sheet provided with a cured layer of a radiation-curable pressure-sensitive adhesive which is not adhered in a normal state, but is adhered by applying a predetermined pressure by bringing the superposed surfaces into contact with each other, A pressure-sensitive adhesive printing sheet in which yellowing is suppressed, characterized in that a photopolymerization initiator containing a tertiary amine group used in a cured layer and radicals derived therefrom are not substantially left. 2. A method according to claim 1, wherein a predetermined portion of the superposed surface of the base sheet is
When manufacturing a pressure-sensitive adhesive printing sheet provided with a cured layer of a radiation-curable pressure-sensitive adhesive, which is not adhered in a normal state but is adhered by applying a predetermined pressure by bringing the superposed surfaces into contact with each other. 2. The photosensitive composition according to claim 1, wherein a photopolymerization initiator containing a tertiary amine group used in the cured layer and radicals derived therefrom are volatilized and removed by heat treatment after irradiation with radiation. Manufacturing method of pressure-sensitive adhesive printing sheet. 3. Immediately after irradiation, at 80 to 150 ° C.
The method according to claim 2, wherein the heat treatment is performed for 30 seconds.