JP4763529B2 - Adhesive paper for back glue and adhesive paper for back glue - Google Patents

Description

  The present invention relates to an adhesive paper for back glue and an adhesive paper for back glue. More specifically, for example, for post-glue having excellent ink-jet recording ability capable of printing and printing variable information by ink-jet recording and excellent offset printing ability capable of offset-printing beautiful concealment information. The present invention relates to an adhesive paper and an adhesive paper for back glue that can realize a concealment paper that can be easily peeled without damaging the concealment information recording surface.

  As the post-adhesive adhesive paper, the mainstream is a film type in which a peelable adhesive film or the like is interposed between two adhesive paper coated papers or the folded inner surface of one adhesive paper. In recent years, in addition to such film types, coating type post-adhesive adhesive paper in which an adhesive layer is formed on the printed surface after application of UV curable resin after printing and printing has been studied. .

  These adhesive papers for back glue are superior in glossiness on the adhesive layer surface and have a high-class feeling compared to so-called adhesive paper for front glue, in which an adhesive layer is first formed and printed and printed on the adhesive layer surface. . However, since the raw material for the film as the adhesive layer and the ultraviolet curable resin layer is very expensive compared with the raw material for the adhesive layer formed on the adhesive paper for pre-glue, there is a problem that the manufacturing cost is high.

  On the other hand, the adhesive paper for pre-adhesive is lower in manufacturing cost than the adhesive paper for post-adhesive, but because information is recorded on the adhesive layer, a part of the record on the adhesive layer is transferred to the opposite side at the time of peeling. The so-called show-through occurs. Therefore, when using the adhesive paper for the front paste, the information recording is limited to a method capable of fixing the ink by heating such as an electrophotographic method. This method is not suitable for an ink jet recording method that has remarkably advanced as a method.

  Therefore, the development of adhesive paper for post glue that can be applied to the ink jet recording method is underway. For example, high-speed ink jet printing such as general coated paper and foam paper with alkylamine / epihalohydrin polycondensate attached on both sides. A concealing postcard has been proposed in which a specific adhesive layer containing succinic anhydride is provided on a recording sheet that can be recorded by the system (see Patent Document 1). The recording sheet used for the concealment postcard can certainly print and print information on the adhesive surface, that is, the surface on which the adhesive layer is provided by the ink jet recording method, and is relatively satisfactory in quality. A recording surface is obtained. However, when information is printed or printed on the surface of the recording sheet that is not provided with an adhesive layer, for example, an addressed surface by an ink jet recording method, the information recording surface becomes unclear due to printing rubbing or water wetting.

  Furthermore, when manufacturing post-adhesive adhesive paper, printing and printing on a base paper provided with an adhesive layer often uses an inkjet recording method and an offset printing method in combination. For example, in confidential postcards using adhesive paper for back glue, variable information such as confidential information and personal information is printed and printed by the inkjet recording method, and form printing such as frame printing and pattern printing other than these variable information Is printed by the offset printing method. For this reason, the adhesive sheet for post glue requires both excellent ink jet recording aptitude and offset printing aptitude. However, when information is printed on the recording sheet used for the concealment postcard by the offset printing method, offset ink sinks and it is difficult to obtain a beautiful information recording surface.

  Accordingly, various developments have been made for the purpose of providing an adhesive paper for post-glue that simultaneously exhibits ink jet recording suitability and offset print suitability. For example, a coating liquid containing a water-soluble binder containing polyvinyl alcohol, a pigment containing silica, and a water-soluble fluidity-improving / water-retaining agent is applied to at least one surface of the base paper and has a specific smoothness. Dye-fixing function for coated paper for pseudo-adhesive paper with a coating layer (see Patent Document 2), and a condensate obtained by reacting a cationic acrylic resin with ammonia and amines and epihalohadrines as necessary There has been proposed a pseudo-adhesive recording paper (see Patent Document 3) in which an adhesive layer that is pseudo-adhered by pressure is provided on at least one surface of a recording paper containing other cationic resin having the above.

  The pseudo-adhesive paper coated paper and the pseudo-adhesive recording paper can certainly be applied to both the inkjet recording method and the offset printing method. However, in the case of the coated paper for pseudo-adhesive paper, ink sinks in the coating layer containing silica with high oil absorption, and it is difficult to obtain a clear information recording surface. Since the surface strength is low, there is a problem that halftone dots are lost and printing defects are likely to occur in high-speed offset printing. On the other hand, in the case of the pseudo-adhesive recording paper, the coating layer is not provided on the recording paper containing the cationic acrylic resin, and the recording paper without such a coating layer has a high definition. Printing is difficult. Therefore, in order to obtain a high-definition information recording surface, for example, an expensive ultraviolet curable ink must be used, which is inappropriate for a normal offset printing method in which cost reduction is to be achieved.

In addition to the above, various types of adhesive paper for back glue have been proposed. However, the adhesive paper for back glue currently used for these adhesive papers for general use is generally used for offset printing. In most cases, these coated papers have a problem that ink jet recording suitability is low.
JP 2001-219680 A JP 2005-307387 A JP 2006-70383 A

  The present invention has been made in view of the above-described background art. For example, it is possible to perform offset printing of excellent concealment information and excellent ink jet recording aptitude capable of printing and printing variable information by ink jet recording. Even if an adhesive layer is provided with a post glue adhesive paper with excellent offset printability and a post glue adhesive on the print / print information, it can be easily peeled off without damaging the concealed information recording surface. It is an object of the present invention to provide an adhesive paper for back glue that can realize a concealment paper.

That is, the present invention
An adhesive paper for back glue for providing a peelable adhesive layer including a base paper,
The base paper is made from wood pulp as a main raw material,
A clear coat layer containing starch, a water-resistant agent and a sizing agent is provided on both sides of the base paper,
On one of the clear coat layers, a coating layer is provided,
The surface of the other clear coat layer and the surface of the coating layer have been flattened,
After the information is printed or printed on the flattened coating layer, the peelable adhesive layer is provided, and the adhesive sheet for post glue and the base paper are provided with the peelable adhesive layer Adhesive paper for post glue,
The base paper is made from wood pulp as a main raw material,
A clear coat layer containing starch, a water-resistant agent and a sizing agent is provided on both sides of the base paper,
On one of the clear coat layers, a coating layer is provided,
The surface of the other clear coat layer and the surface of the coating layer have been flattened,
The present invention relates to an adhesive paper for back glue, in which the peelable adhesive layer is provided after information is printed or printed on the flattened coating layer.

  The adhesive sheet for post glue of the present invention has, for example, excellent ink jet recording aptitude capable of printing and printing variable information by ink jet recording, and excellent offset printing aptitude capable of offset printing of beautiful concealment information. It has. Therefore, after printing and printing information on the adhesive sheet for post glue of the present invention, the adhesive paper for post glue of the present invention provided with a peelable adhesive layer is adhered at a predetermined pressure, so that it is clear and beautiful. A concealment sheet that can be easily peeled without damaging the concealment information recording surface can be obtained.

(Embodiment)
As described above, the adhesive sheet for post glue of the present invention includes a base paper and is provided with an adhesive layer. The adhesive paper for post glue of the present invention is attached to the adhesive sheet for post adhesive. However, instead of simply providing an adhesive layer on one side of the base paper, a clear coat layer is first provided on both sides of the base paper, and then applied on one clear coat layer. A work layer is provided, and after information is printed or printed on the coating layer, an adhesive layer is further provided.

First, the base paper used in the present invention will be described. In order to obtain the base paper used in the present invention, for example, wood pulp appropriately selected from softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), etc. The main raw material is contained by mass% or more, and various types of used paper pulp, synthetic pulp and the like can be used as appropriate. The pulp is beaten to, for example, a beating degree of 300 to 600 mL (Canadian Standard Freeness (C.S.F.)), and then a filler such as clay, kaolin, calcium carbonate, titanium dioxide, etc .; starch, polyvinyl alcohol, polyacryl Paper strength enhancer such as amide; Wet paper strength enhancer such as melamine resin, urea resin, polyamide epichlorohydrin, polyacrylamide; fluorescent whitening agent; colored dyes and pigments; In accordance with a conventional method using a normal paper machine such as a paper machine or a long paper machine, paper is made under acidic or neutral conditions, for example, so that the basis weight is about 110 to 150 g / m ^2. The base paper used for can be manufactured.

  The sizing degree of the base paper can be adjusted by using an internally added sizing agent such as rosin sizing agent, alkenyl succinic anhydride, alkyl ketene dimer, petroleum resin sizing agent and the like.

  Of the additives, when a wet paper strength enhancer is used, a value measured after the base paper obtained by papermaking is dipped in water for 10 minutes to be wetted, for example, has a tensile strength of 20N. It is preferable to adjust the amount of the wet paper strength enhancer so that the paper delamination strength is about 0.5 N / 15 mm (MD) or more. Usually, it is desirable to add in the range of about 0.05 to 2.0% by mass, preferably about 0.5 to 1.0% by mass with respect to the absolute dry mass of pulp.

  By keeping the tensile strength when wet above about 20 N / 25 mm (MD), the strength of the base paper where the paper strength decreases when wet is maintained, and the hydration bond of the adhesive becomes stronger and the adhesive strength increases when wet. However, it can be made peelable without tearing the base paper.

  Further, by setting the paper delamination strength at the time of wetting to about 0.5 N / 15 mm (MD) or more, even when the hydration bond of the adhesive is strengthened at the time of wetting and the adhesive strength is increased, the surface of the base paper can be removed. It can be made peelable without causing damage.

  The clear coat layer provided on both surfaces of the base paper contains starch, a water resistance agent and a sizing agent.

  Although the starch is not so excellent in water resistance, it has high adhesion to the base paper. Although there is no limitation in particular in the kind of starch used for this invention, Modified starch is preferable and, among these, the oxidized starch excellent in moderate viscosity and film property can be used especially suitably.

  The oxidized starch is obtained at a relatively low cost. For example, starch such as corn, potato, tapioca, sweet potato, wheat, rice is dispersed in water, and sodium hypochlorite, ammonium persulfate, hydrogen peroxide. It can be obtained by adding an oxidizing agent, etc., heating to about 40 to 150 ° C., and depolymerizing the starch. The viscosity of the oxidized starch can be adjusted by the addition amount of the oxidizing agent, reaction time, temperature, and the like.

  In addition to the modified starch, for example, cationic starch can be used as the starch, but an undesirable reaction may occur with the water-resistant agent described later, and the water-resistant agent may be, for example, a cationic polyamine. In the case of a resin, since the function may be impaired, it is preferable to consider the amount used and a combination with a water-proofing agent.

  The water-proofing agent (ink fixing agent) is a component that imparts wetting resistance, and can improve the uniformity of the coating layer provided on the clear coat layer.

There are no particular limitations on the type of water-proofing agent used in the present invention, and examples thereof include cationic water-proofing agents that are usually used for inkjet recording materials. Examples of the cationic water-resistant agent include:
(1) Polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine or derivatives thereof (2) Acrylic polymers having secondary amino group, tertiary amino group, quaternary ammonium group, etc. (3) Polyvinylamine and polyvinyl Amidines (4) Dicyan cationic polymer represented by dicyandiamide-formalin copolymer (5) Polyamine cationic polymer represented by dicyandiamide-polyethyleneamine copolymer (6) Epichlorohydrin-dimethylamine copolymer Compound (7) Diallyldimethylammonium-SO ₂ polycondensate (8) Diallylamine salt-SO ₂ polycondensate (9) Diallyldimethylammonium chloride polymer (10) Diallyldimethylammonium chloride-acrylamide copolymer (11) Allyla Copolymers of amine salts (12) Dialkylaminoethyl (meth) acrylate quaternary salt copolymers (13) Acrylamide-diallylamine copolymers (14) Cationic resins having a 5-membered ring amidine structure it can. Among these, the cationic polyamine-based resin is excellent in cost effectiveness and can be particularly preferably used.

  The sizing agent is a component that imparts a size effect to the clear coat layer. The type of the sizing agent used in the present invention is not particularly limited, but an alkyl ketene dimer sizing agent that exhibits a stable sizing effect even in the neutral region is preferable. When the alkyl ketene dimer sizing agent is used, the compatibility between the clear coat layer and the coating liquid for forming the coating layer described later is good, and the coating layer can be provided more uniformly on the clear coat layer. In addition, a good layered configuration can be maintained among the base paper, the clear coat layer, and the coating layer.

  As described above, in the present invention, starch, a water resistance agent and a sizing agent are used in combination, and the water penetration into the base paper is moderately induced. For example, latex in the coating layer is slightly present in the clear coat layer. It penetrates the surface and develops the anchor function of the coating layer. Therefore, when the adhesive sheet for post glue provided with an adhesive layer on the adhesive sheet for post glue is peeled after being pseudo-bonded by a predetermined method, it is clear and beautiful without causing damage to the coating layer. The concealment information recording surface can be obtained as it is.

  Further, a suitable application of the adhesive sheet for post glue and the adhesive paper for post glue of the present invention is, for example, a pressure-sensitive postcard in which an adhesive layer is provided with an adhesive for post glue after concealment information is printed and printed on the coating layer. This is concealment paper such as paper. The pressure-bonded postcard paper may be wetted by wind and rain at the mailing stage. This wetting has a great effect on the adhesiveness of the adhesive, sometimes the pseudo-adhesive surface cannot be peeled off, the adhesive layer peels off from the base paper, and the description information such as concealment information is damaged. There is.

  As a means for solving the above problem, for example, it is conceivable to impart water resistance to the adhesive sheet for the post glue, but the improvement in water resistance of the adhesive paper for the post glue not only increases the cost due to the chemicals used but also after use. It is not preferable from the viewpoint of effective use of resources because it becomes impossible to collect and reuse the adhesive paper for post glue as waste paper and to incinerate it.

  In order to reuse the adhesive paper for post glue as a resource raw material, it is necessary that the adhesive layer is easily removed from the base paper and can be separated. The adhesive paper for post glue of the present invention is not provided with a coating layer directly on the base paper, but a specific clear coat layer comprising starch, a water-resistant agent and a sizing agent is provided on both sides of the base paper. In addition, since the coating layer is provided on the clear coat layer and the adhesive layer is further provided on the coating layer after printing or printing of information, the coating layer and The adhesive layer can be easily separated and removed from the base paper.

  The ratio of starch, water-proofing agent and sizing agent that forms the clear coat layer, the effect of each component is expressed in a well-balanced manner, and the effect of moderately attracting moisture penetration into the base paper as described above is fully expressed. Although it does not specifically limit as long as it is performed, For example, it is preferable that starch: waterproofing agent: size agent (mass ratio) is 10-30: 10-30: 0.05-0.40, and 15-25: 15 More preferably, it is 25: 0.15-0.30.

In order to provide a clear coat layer containing starch, a water-proofing agent and a sizing agent on both sides of the base paper, for example, a clear coating solution in which starch, a water-proofing agent and a sizing agent are appropriately blended at a mass ratio in the above range, For example, a method of coating on both sides of the base paper by a film transfer method using a size press or a size press equipped with a gate roll coater can be employed. The coating amount of the clear coating solution is preferably 1.5 to 3.5 g / m ² , more preferably 1.7 to 3.3 g / m ² . When the coating amount of the clear coat liquid is less than the lower limit value, the effect of providing the clear coat layer may not be sufficiently exhibited, and when the upper limit value is exceeded, the cost increases and the base paper A coating layer is formed on the surface, the ink absorption drying property is lowered, and there is a possibility that the ink shows through or the peel strength at the adhesive layer is lowered.

  In addition, although there is no limitation in particular in the thickness of a clearcoat layer, it is preferable that it is about 0.1-2.0 micrometers, for example.

  A coating layer is provided on one of the clear coat layers thus formed. Although there is no limitation in particular in the coating liquid for forming this coating layer, For example, the coating liquid which has an adhesive composition and a pigment as a main component can be used suitably.

  Examples of the adhesive composition include starch derivatives such as cationic starch, etherified starch, phosphate esterified starch and hydroxyethyl etherified starch; cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; casein, gelatin, soy protein, polyvinyl Alcohol or derivatives thereof; conjugated diene copolymer latex such as polyvinyl pyrrolidone, maleic anhydride resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer; polymer or copolymer of acrylate ester and methacrylate ester Acrylic polymer latex such as polymer; Vinyl polymer latex such as ethylene-vinyl acetate copolymer; Functional group-modified polymer latex with functional group-containing monomers such as carboxyl groups of these various polymers; Latex cationized with a cationic group in the polymer, latex with the polymer surface cationized with a cationic surfactant, polymerized under cationic polyvinyl alcohol, and the cationic polyvinyl alcohol is distributed on the polymer surface Latex, polymerized in a suspension dispersion of cationic colloid particles, and latex in which the cationic colloid particles are distributed on the polymer surface; aqueous adhesives such as thermosetting synthetic resins such as melamine resin and urea resin Polymer or copolymer of acrylic acid ester or methacrylic acid ester such as polymethyl methacrylate; polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, alkyd resin, etc. Adhesives and the like are listed, and these may be used alone or in combination of two or more. It can be used Te. Among these, highly versatile styrene butadiene latex and starch derivatives are excellent in cost effectiveness and are preferably used. Considering that the main use of the resulting adhesive sheet for post glue is postal mail, the content of acrylonitrile, which is susceptible to yellowing, is low, more preferably a styrene butadiene latex that does not contain, and the glass transition temperature is 0 ° C. Styrene butadiene latex having a flexibility of less than is particularly preferred.

  Examples of the pigment include light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, delaminated kaolin, calcined kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, and satin white. , Aluminum silicate, diatomaceous earth, calcium silicate, synthetic amorphous silica, colloidal silica, colloidal silica modified with cation, aluminum hydroxide, alumina, alumina hydrate, lithopone, zeolite, hydrohalosite, magnesium hydroxide, etc. Inorganic pigments: Examples thereof include plastic pigments of styrene or copolymers thereof, polyethylene, microcapsules, urea resins, organic pigments such as melamine resins, and the like, and these can be used alone or in combination of two or more. Among these, calcium carbonate and clay are preferably used because they are relatively inexpensive, for example, are excellent in high-speed coating suitability with a blade coater, and have excellent post paste suitability.

  When the coating liquid is mainly composed of an adhesive composition and a pigment, the ratio of the adhesive composition and the pigment is not particularly limited, but the total amount of the adhesive composition is 100 parts by weight of the pigment. It is preferable to adjust so that it may become about 5-25 mass parts, and also about 7-23 mass parts. If the total amount of the adhesive composition is less than the lower limit, the strength of the coating layer may be reduced. If the total amount is greater than the upper limit, the adhesion between the coating layers is increased. In the manufacturing process of the adhesive sheet for post glue, troubles such as blocking and sticking may occur, and the cost tends to increase.

  In the present invention, when the coating liquid is mainly composed of an adhesive composition and a pigment, styrene butadiene latex and starch derivative are used as the adhesive composition, and calcium carbonate and clay are used as the pigment, the ratio of these four components As for (solid content mass ratio), clay: calcium carbonate: styrene butadiene latex: starch derivative is 30-60: 30-60: 3-20: 2-10, and further 35-55: 35-55: The ratio of 5 to 15: 3 to 8 is particularly suitable from the viewpoint that physical properties such as strength and viscosity of the coating layer are imparted in a well-balanced manner.

  In addition to the adhesive composition and the pigment, the coating liquid includes, for example, a pigment dispersant, a thickener, a fluidity improver, an antifoaming agent, a foam suppressant, a lubricant, a release agent, a foaming agent, Ordinary additives such as penetrants, colored dyes, colored pigments, fluorescent brighteners, UV absorbers, antioxidants, antiseptics, antibacterial agents, water resistance agents, dye fixing agents, and the like, for example, stearic acid, calcium stearate Add auxiliaries such as oleic acid, calcium oleate, ammonium oleate, lecithin, polyethylene, wax, and derivatives such as lubricants to prevent dusting and dirt during calendaring as needed. Can do.

  In order to provide a coating layer on one clear coat layer, for example, a coating solution in which an adhesive composition, a starch derivative and the like are appropriately blended at a mass ratio in the above range is used, and one clear coating is performed with a normal coating machine. A method of coating on the coat layer can be employed.

  Examples of the coating machine include an air knife coater, a blade coater, a rod metering coater, and a curtain coater. From the viewpoint of suppressing the occurrence of coating defects such as streaks, in principle, the use of an air knife coater or curtain coater that hardly adheres glue to the coating part is preferred. Blade coater, rod coater, etc. that can easily obtain a coating layer with higher smoothness than curtain coater and air knife coater, considering the occurrence of streaks and the like, and the difficulty and operation cost of flattening treatment in the next process It is desirable to use

The coating amount of the coating liquid is preferably 5 to ²⁰ g / m ² , more preferably 10 to 15 g / m ² . When the coating amount of the coating liquid is less than the lower limit value, it becomes difficult to obtain a desired smoothness even by the flattening process in the next step, and at the time of forming the adhesive layer in the subsequent step. There is a possibility that the effect of reducing the consumption of the pseudo-adhesive (post paste) may not be sufficiently obtained. When the upper limit is exceeded, it is difficult to ensure the desired surface strength of the coating layer, and In addition to sticking glue on the coating roll during construction, it may easily cause operational and quality problems, and it may be difficult to ensure ink jet recording suitability by immersing the coating liquid in the non-coated surface. .

  In addition, although there is no limitation in particular in the thickness of a coating layer, it is preferable that it is about 3-20 micrometers, for example.

  Next, a planarization process is performed on the surface of the coating layer and the surface of the other clear coat layer on which the coating layer is not provided. In the adhesive paper for back glue and the adhesive paper for back glue of the present invention, for example, variable information is printed and printed on the clear coat layer by ink jet recording to be a destination surface, and concealment information is offset printed on the opposite coating layer. And can be non-addressed.

  For example, a super calender can be used to perform the planarization treatment on the surface of the other clear coat layer and the surface of the coating layer. Originally, the super calender is used for flattening a coated paper having a coating layer on both sides, but in the present invention, it is further provided on one side of the clear coat layer and on the opposite side of the clear coat layer. By performing the flattening treatment with the coating layer, the denseness of the coating layer surface is improved, and the unevenness caused by the immersion of starch, water-resistant agent and sizing agent on the surface of the clear coating layer is flattened. The definition of printing and printing information can be improved.

  The flattening treatment may be performed by a so-called on-machine calendar that forms a series with the coating machine, or may be performed by a completely separate off-machine calendar instead of a series of coating machines. The type of calendar is not particularly limited. Moreover, as a calender roll which is a smoothing process means, what combined the metal roll and the elastic roll, and what combined metal rolls can be used.

  In particular, it is preferable to install an on-machine calendar made of a thermal soft calendar at the subsequent stage of the coating equipment and perform the flattening process. The thermal soft calender may be heated by circulating a heat medium such as oil, but the surface temperature of the thermal soft calender is limited to about 180 ° C. In order to make paper at high speed, the metal roll is equipped with an internal heating device by electromagnetic induction that can control the division temperature in the width direction, and the surface temperature is about 230 ° C. or more, especially about 230 to 500 ° C. It is desirable to be adjusted to. A specific example of such a metal roll is one in which an induction coil is wound around an iron core in a shell to heat a heat medium passing through a jacket chamber.

  In addition, for example, the surface temperature of the metal roll is 250 to 380 ° C., in particular, more than 300 ° C. and 380 ° C. or less, and the moisture content at the flattening equipment inlet is 4 to 10%, more preferably 6 to 9 In the range of%, by preventing the paper from being crushed over the entire layer at the lowest possible nip pressure, it is possible to prevent a decrease in bulk and to further improve the smoothness of both the coating layer and the clear coat layer.

  The smoothness of the flattened clear coat layer is such that the Beck smoothness conforming to “Smoothness test by paper and paperboard-Beck smoothness tester” described in JIS P 8119 is 60 seconds or more, and further 65 seconds or more. Preferably there is. When the Beck smoothness of the clear coat layer is less than the above value, the appearance when ink-jet recording is performed on the obtained adhesive sheet for post-glue is deteriorated, and the printability is insufficient, such as bleeding on the printed matter. There is a fear. The upper limit of the Beck smoothness is not particularly limited, but particularly when a high-speed ink jet printer exceeding a processing speed of 100 m / min is used, bleeding tends to occur, and the performance and cost of the coating machine are low. Considering this point, the upper limit is usually about 100 seconds. In order to set the Beck smoothness of the clear coat layer to, for example, about the above-mentioned range, after applying the clear coat liquid, for example, a flattening means such as a machine calendar, specifically, the calendar pressure may be appropriately adjusted. .

  As for the smoothness of the flattened coating layer, the Beck smoothness conforming to the “smoothness test by the paper and paperboard-Beck smoothness tester” described in JIS P 8119 is 125 seconds or more, and further 130 seconds or more. It is preferable that When the Beck smoothness of the coating layer is less than the above value, the glossiness of the coating layer surface is likely to deteriorate and the appearance is liable to occur, and when offset printing is performed on the obtained adhesive sheet for post glue, There is a risk that it will be difficult to make the printed material an excellent aesthetic. Although there is no particular limitation on the upper limit of the Beck smoothness, it is considered that the anchor function of the pseudo-adhesive applied in the next process starts to deteriorate, and the adhesive layer may be unintentionally peeled off at the time of peeling. Then, the upper limit is usually about 200 seconds.

  Next, after the information is printed or printed on the flattened coating layer of the adhesive sheet for post glue obtained as described above, a peelable adhesive layer is provided. In order to form the adhesive layer, for example, an adhesive liquid containing a pseudo-adhesive (a peelable adhesive for post glue) may be applied on the coating layer. The pseudo adhesive is not particularly limited, but for example, an emulsion type adhesive is preferably used. As the emulsion-type adhesive, for example, an acrylic emulsion obtained by emulsion polymerization of acrylic acid ester and acrylic acid, methacrylic acid ester or the like is preferable, and a solid content concentration of about 5 to 15% is particularly preferable. If the amount of the acrylic emulsion used is large, the adhesive strength becomes too large, and the surface of the adhesive paper for post-glue may be torn at the time of peeling. Conversely, if the amount used is too small, the adhesive strength is too small during mailing. Therefore, it is preferable to adjust appropriately so that the adhesive layer contains about 5 to 20% by mass in solid content.

  In addition to controlling the adhesive force, it is preferable that the adhesive layer contains silica so that show-through is less likely to occur during peeling. The content of the silica in the adhesive layer is preferably about 5 to 15% by mass in solid content. The silica preferably has an average particle diameter of about 3 to 20 μm. If the average particle size is smaller than the lower limit value, the adhesive strength is likely to fluctuate due to wetting or environmental changes during delivery. If the average particle size is larger than the lower limit value, the adhesive force may be excessively suppressed.

  Furthermore, in the adhesive layer, in addition to the pseudo-adhesive and silica, a thickener, a fluidity improver, an antifoaming agent, a defoaming agent, a penetrating agent, etc. as an auxiliary agent are obstructed. It can also be contained as appropriate as long as it is not.

In order to provide a peelable adhesive layer after printing or printing information on the flattened coating layer, for example, an adhesive liquid appropriately blended with pseudo adhesive, silica, etc., for example, roll coater, gravure coater, lip What is necessary is just to apply by the normal method using various coating machines, such as a coater, and a printing machine. The coating amount of the adhesive solution, 15 to 30 g / m ² by solid content, and more preferably from 17~28g / m ^2. If the coating amount of the adhesive liquid is less than the lower limit value, the adhesive force of the adhesive layer may be too weak, and if it exceeds the upper limit value, the adhesive layer is bonded when formed and then bonded. There is a risk of the layer sticking out of the adhesive sheet for back glue.

  As the peel strength between the formed adhesive layers (pseudo-adhesive strength), a pressure of about 390 N / cm or more of linear pressure measured according to “Paper and paperboard—Test method for tensile properties” described in JIS P 8113 is used. It is preferable that the T-peeling force when bonded together is about 0.2 to 0.5 N / 15 mm, more preferably about 0.25 to 0.45 N / 15 mm. If the T-peeling force is smaller than the lower limit value, for example, the adhesive surface may be peeled off during sorting at a post office or in the middle of mailing. If the T-shaped peeling force is larger than the upper limit value, the adhesive surface may be peeled off. There is a tendency that the surface of the adhesive paper for glue is torn or it is difficult for the recipient to easily peel it off. In addition, it is preferable to appropriately adjust the coating amount of the adhesive liquid so that the peel strength between the adhesive layers is within the above range.

  The thickness of the adhesive layer is not particularly limited, but may be, for example, in the range of 10 to 100 μm, and preferably about 20 to 50 μm.

Regarding the size property of the flattened clear coat layer surface in the post paste adhesive paper and post paste adhesive paper obtained as described above, the paper and paperboard described in JIS P 8140 on the flattened clear coat layer surface side is used. - water absorption test method - was measured according to Cobb method ", 10 seconds Cobb sizing degree 10 to 30 g / m ^2, preferably further is 12~28g / m ^2. When the 10-second Cobb sizing degree is smaller than the lower limit value, that is, when the water absorption is low, in ink jet recording usually performed at a printing speed of 150 m / min or more, the printed ink is completely dried by an auxiliary drying device. Instead, the ink may be transferred to a metal roll provided immediately after the auxiliary drying device, and the transferred ink may be re-transferred to the adhesive sheet for post-gluing and cause stains. In addition, when the 10-second Cobb sizing degree is larger than the upper limit value, that is, when the water absorption is high, the ink set property and the image water resistance in the ink jet recording are good, but the ink jet ink has a large blur and is called a feathering dot. The shape may be deteriorated and the quality of recorded characters may be deteriorated.

  The adhesive paper for back glue and the adhesive paper for back glue of the present invention is not simply provided with a coating layer on both sides of the base paper, but first contains starch, a water resistant agent and a sizing agent on both sides of the base paper. A specific clear coat layer is provided, a coating layer is provided on one clear coat layer, and the surface of the other clear coat layer and the surface of the coating layer are flattened. The variable information can be printed and printed on the formed clear coat layer by ink jet recording to be the address surface, and the concealment information can be offset printed on the opposite flattened coating layer to be the non-address surface. As described above, the post-adhesive adhesive paper and the post-adhesive adhesive paper of the present invention perform, for example, excellent ink jet recording aptitude capable of printing and printing variable information by ink jet recording, and offset printing of beautiful concealment information. It has excellent offset printability that can be performed.

  Next, although the adhesive paper for back glue and the adhesive paper for back glue of this invention are demonstrated in detail based on an Example, this invention is not limited only to these Examples.

Examples 1-7 and Comparative Examples 1-9
Raw material pulp consisting of NBKP 5 mass% and LBKP 95 mass% is made with a gap former paper machine, flattened with a two-stage, two-stack thermal soft calender, and a base paper with a basis weight of 120 g / m ² is obtained. Prepared.

  Next, a clear coat solution is prepared with the composition shown in Table 1, and the clear coat solution is applied on both sides of the base paper with the coating method and coating amount shown in Table 1 to form a clear coat layer. I let you. Its thickness was about 0.2 μm.

  Next, the coating liquid was prepared with the composition shown in Table 2, and it applied on said one clear coat layer by the coating system and coating amount shown in Table 2, and formed the coating layer. Its thickness was about 12 μm. In Comparative Example 3, no coating layer was provided.

  Next, a soft calender 2 in which a base paper in which a clear coat layer is formed on one side and a clear coat layer and a coating layer are laminated on the opposite side is combined with a metal roll (120 ° C.) and an elastic roll. Paper was passed through the stack, and the surface of the coating layer and the surface of the other clear coat layer where the coating layer was not formed were subjected to a flattening treatment to obtain an adhesive paper for post glue. In Comparative Example 3, since the coating layer was not provided, the planarization treatment was performed on the clear coat layers on both sides. In Comparative Examples 4 to 9, no planarization treatment was performed on any surface.

  As the smoothness of the flattened clear coat layer and the smoothness of the flattened coating layer, in accordance with “Smoothness test by paper and paperboard—Beck smoothness tester” described in JIS P 8119, The degree was measured. The results are shown in Table 3.

  Next, after printing and printing information by a normal method on the coating layer subjected to the flattening treatment of the obtained adhesive sheet for post glue, 100 parts by mass (dry weight) of acrylic emulsion and silica ( Adhesive liquid prepared by mixing 100 parts by mass with secondary aggregates (average particle size: 10 μm) is applied with the coating method and coating amount shown in Table 3 to form an adhesive layer having a thickness of about 25 μm. Thus, an adhesive paper for post glue was obtained. In Comparative Example 3, since no coating layer was provided, information was printed / printed on one of the flattened clear coat layers. In Comparative Examples 4 to 9, the coating layer was not flattened. After printing and printing information, an adhesive layer was provided.

  About the obtained adhesive paper for post glue, as a peeling strength (pseudo-adhesion strength) between the formed adhesive layers, the T-peeling force when adhered by applying a pressure of about 390 N / cm to the following method Therefore, it was measured. The results are shown in Table 3.

(Peel strength)
The adhesive paper for back glue is cut into a strip shape with a width of 15 mm, and in accordance with “Paper and paperboard—Test method for tensile properties” described in JIS P 8113, using a Tensilon universal testing machine at a peeling speed of 300 mm / min. The 180 ° peel strength was measured.

  Next, the characteristics of the adhesive paper for back glue and the adhesive paper for back glue were examined according to the methods of Test Examples 1 to 3 below. The results are shown in Table 4.

Test Example 1 (Applicability of ink jet recording of clear coat layer (address surface) (characteristics of adhesive paper for back glue))
(1) Initial printing (bleeding)
Using an inkjet printer (Canon, model number: PIXUS9900i) set with black ink (Cytex Digital Printing Co., Ltd., No. 1007), a flattened clear coat layer (address face) of adhesive paper for back glue On the top, ruled line printing with 4 points and a length of 20 cm was continuously performed 25 times at intervals of 5 mm, and bleeding of each ruled line was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: No bleeding at all 25 times.
◯: There is no bleeding more than 20 times.
Δ: Bleeding occurs at a frequency exceeding 5 times.
X: More than half of the ruled lines are blurred.

(2) Water resistance After performing ink jet recording using the same ink jet printer as described above, the adhesive paper for glue was immersed in tap water for 30 seconds, and then excess water was absorbed with filter paper and air dried. Thereafter, the bleeding of the recorded image was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: No bleeding is observed.
◯: Slight bleeding is observed, but there is no practical problem.
(Triangle | delta): There exists a bleeding and there exists a problem practically.
X: The bleeding is remarkable.

(3) Cobb sizing degree According to JIS P 8140 "Paper and paperboard-Water absorption test method-Cobb method" It was measured.

Test example 2 (offset printing suitability (characteristics of adhesive paper for post glue))
When a ruled line is printed on the clear coat layer (address side) or adhesive layer (rear paste surface) of the adhesive paper for back paste using an offset printing machine for business forms (manufactured by Komori Corporation, model number: Sprint 25) The ink bleeding, displacement, and image reproducibility were visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: There is no ink bleeding and misalignment, and halftone dot reproducibility and image reproducibility are excellent.
◯: Although slight bulging is observed in the ruled line portion, it is not problematic in practical use.
Δ: Halftone dots are missing, and the fineness of the ruled line portion / contour is low.
X: There are many missing dots, and blurring and misalignment of the image area are remarkable.

Test Example 3 (Adequacy of post glue (characteristics of adhesive paper for post glue))
After performing inkjet recording on the clear coat layer (address side) of the adhesive paper for post-glue in the same manner as in Test Example 1 and performing offset printing on the adhesive layer (post-glue surface) in the same manner as in Test Example 2 The adhesive layer is folded in two so that the adhesive layers face each other, and a pressure-bonding sealer (manufactured by Dai Nippon Printing Co., Ltd., model number: MS-9100) is used to perform pressure-bonding treatment under the conditions of the sealer gap 17 to add the facing adhesive layers. The cover sheet was obtained by pressure bonding.

About the obtained concealment paper, 20 adult males and females conduct sensibility tests such as peelability, visibility (detailed degree of printed information on the back glue surface and address surface), and touch, and evaluate based on the following evaluation criteria Got.
(Evaluation criteria)
1: Peelability, visibility, and touch are all excellent.
2: Peelability, visibility and touch are good, and there are no practical problems.
3: There is some difficulty in peelability, peeling occurs on the peeled surface, and visibility is not good.
4: Peeling is difficult, damage occurs on the peeled surface, and visibility is poor.

From the evaluation results of 20 persons, the post paste suitability of the adhesive paper for post paste was comprehensively evaluated based on the following evaluation criteria. Table 4 shows the results of this comprehensive evaluation.
(Evaluation criteria)
A: Evaluation 1 is 18 or more.
A: Evaluation 1 is 12 to 17 people.
(Triangle | delta): Evaluation 4 is 12-17 persons.
X: Evaluation 4 is 18 or more.

  In the adhesive paper for back glue of Examples 1 to 7, a specific clear coat layer is formed on both sides of the base paper, a coating layer is formed on one clear coat layer, and the surface of the other clear coat layer And the surface of the coating layer are both flattened, and the adhesive paper for back glue of Examples 1 to 7 is formed on the flattened coating layer of the adhesive paper for post glue. It has been done. Therefore, as shown in Table 4, in addition to the adhesive layer having a suitable peel strength, when ink jet recording is performed on the flattened clear coat layer surface, there is almost no bleeding, excellent water resistance, and a suitable cobb size. The clear coat layer is excellent in ink jet recording suitability, and both the clear coat layer and the post glue layer are excellent in offset print suitability.

  On the other hand, since the clear coat layer is formed with a general clear coat liquid in the adhesive paper for back paste and the adhesive paper for back paste of Comparative Examples 1 to 3, the peel strength of the adhesive layer is low, Among the characteristics, it can be seen that, especially, ink jet recording has a large amount of bleeding in the clear coat layer and is inferior in offset printing suitability and post paste suitability. Particularly, in Comparative Example 3, since the coating layer is not formed, the overall result is bad.

  In addition, in the adhesive sheets for back glue and the adhesive paper for back glue in Comparative Examples 4 to 9, since the surface of the clear coat layer and the surface of the coating layer are not flattened, ink jet recording is particularly preferable among the characteristics. It can be seen that there is a large amount of bleeding in the clear coat layer when it is applied, and it is inferior to any of the characteristics and does not have excellent characteristics.

Since the adhesive paper for back glue and the adhesive paper for back glue of the present invention are suitable for both ink jet recording and offset printing, for example, various concealment papers that use both ink jet recording and offset printing in the production thereof. Etc. can be suitably used.

Claims (5)

An adhesive paper for back glue for providing a peelable adhesive layer including a base paper,
The base paper is made from wood pulp as a main raw material,
On both sides of the base paper, a clear coat layer containing starch, a cationic polyamine-based resin as a water resistance agent and a sizing agent other than the starch is provided,
On one of the clear coat layers, a coating layer containing latex is provided,
The surface of the other clear coat layer and the surface of the coating layer have been flattened,
An adhesive paper for post glue, on which the peelable adhesive layer is provided after information is printed or printed on the flattened coating layer. The adhesive paper for back paste according to claim 1, wherein the starch is a modified starch, and the sizing agent other than the starch is an alkyl ketene dimer sizing agent. The back paste according to claim 1 or 2, wherein a mass ratio of the starch, the water-resistant agent and a sizing agent other than the starch is 10 to 30:10 to 30: 0.05 to 0.40. Adhesive paper. The coating layer is formed by coating an adhesive composition and a coating liquid mainly composed of a pigment, the adhesive composition is the latex, and the latex is a styrene butadiene latex and The adhesive paper for back paste according to any one of claims 1 to 3 , comprising a starch derivative and containing calcium carbonate and clay as the pigment. It is an adhesive paper for post-glue provided with a peelable adhesive layer on the base paper,
The base paper is made from wood pulp as a main raw material,
On both sides of the base paper, a clear coat layer containing starch, a cationic polyamine-based resin as a water resistance agent and a sizing agent other than the starch is provided,
On one of the clear coat layers, a coating layer containing latex is provided,
The surface of the other clear coat layer and the surface of the coating layer have been flattened,
An adhesive paper for post glue, wherein the peelable adhesive layer is provided after information is printed or printed on the flattened coating layer.