JP7055964B2 - Adhesive sheet - Google Patents

Description

The present invention relates to an adhesive sheet, particularly for laser printer printing, and relates to an adhesive sheet for a label, which uses a synthetic resin film as a surface base material and has a paper material as a release material.

An adhesive sheet for a general label has a structure in which a surface substrate, an adhesive layer, and a release material are laminated in this order. As an adhesive sheet for general-purpose labels, a paper material is often used as a surface base material, but a synthetic resin film may be used as a surface base material in order to enhance the appearance and texture of the paper material. be. Further, when used for labels for frozen foods and labels for bottles used around water such as shampoo, a synthetic resin film is used as a surface base material in order to improve moisture resistance and water resistance.
Furthermore, since synthetic resin film has higher tensile strength than paper, it is used as a surface base material for labels for applications such as wet tissue labels that can be used without tearing even after repeated peeling and sticking. There is. In particular, various synthetic papers are used as the synthetic resin film when it is desired to impart a texture similar to that of paper to the surface base material and to have the above-mentioned properties.

By the way, the adhesive sheet for a label is used as a label by printing or printing various indications and information on the surface of a surface base material by various printing means. It is often desired that a printing means for an adhesive sheet using a synthetic resin film as a surface base material can print in the same manner as plain paper, and application to a laser printer is desired.
Further, the release material used for the adhesive sheet for a general-purpose label is discarded after use, and usually, a release material using a paper material as a release base material is used for cost reduction.

For example, in Patent Document 1, in a pressure-sensitive adhesive sheet in which a surface base material, an adhesive layer, and a release sheet are sequentially laminated, the surface base material has a synthetic resin film or synthetic paper as a support, and a pigment on the surface base material. A pressure-sensitive adhesive sheet for a page printer for PPC, which has a coated layer containing an adhesive and a conductive agent and has an adjusted smoother smoothness and surface charge amount of the coated layer, is disclosed.
In the pressure-sensitive adhesive sheet described in Patent Document 1, a synthetic resin film or synthetic paper is used as a surface base material in order to improve water resistance.

Japanese Patent No. 3446234

However, when the adhesive sheet using the synthetic resin film as the surface base material together with the release material having the above-mentioned paper material is printed by a laser printer, extremely large curl occurs.
That is, the heat of the thermal transfer roll that passes when fixing the toner to the surface substrate causes the paper material of the release material to shrink due to drying, resulting in positive curl (the surface substrate is on the outside of the warped surface and the release sheet is on the inside). State) occurs. Further, in the cooling process of passing through the thermal transfer roll, the paper material rapidly absorbs moisture and stretches, and at the same time, heat shrinkage of the synthetic resin film occurs, and reverse curl (opposite to normal curl) occurs.
Due to the difference in elasticity between the paper material that constitutes the release material and the synthetic resin film that constitutes the surface base material due to environmental changes, the dimensional difference between the two becomes large, causing curl. Conceivable.

Furthermore, the curl of the adhesive sheet that has undergone such a history is characterized in that it cannot be restored by a little humidity control.
Therefore, when the synthetic resin film is used as the surface base material, the dimensional change in the thermal history of the release base material constituting the release material is at the same level as that of the surface base material in order to suppress the generation of curl after printing. Synthetic resin films such as synthetic paper are selected, and it is common to avoid using paper materials that have a different degree of dimensional change due to heat from the surface substrate.
However, since the release material using a synthetic resin film is expensive, an adhesive sheet in which the generation of curl is suppressed while using the release material using a paper material has been desired.

Although the pressure-sensitive adhesive sheet described in Patent Document 1 uses a synthetic resin film or synthetic paper as a surface base material, studies on suppressing curl that may occur when a release material using a paper material is used will be investigated. Not broken.

INDUSTRIAL APPLICABILITY The present invention can effectively suppress the generation of curl due to heating immediately after heating and after cooling in an adhesive sheet having a surface base material made of a synthetic resin film and a release material using a paper material, and further, toner. It is an object of the present invention to provide an adhesive sheet having good fixing property.

The present inventor has a clay coat layer on both sides of a paper material as a release material in an adhesive sheet having a surface base material made of a synthetic resin film and a release material using a paper material, and one of the clay coat layers. The present invention has been completed by finding that the above problems can be solved by having a release agent layer on the top and a moisture-proof layer on the other clay coat layer.

That is, the present invention provides the following [1] to [5].
[1] A first clay coat layer and a second clay coat layer are provided on both sides of the paper material, a release agent layer is provided on the first clay coat layer, and a moisture-proof layer is provided on the second clay coat layer. With the release material
An adhesive sheet having an adhesive layer and a surface base material made of a synthetic resin film on the release agent layer of the release material in this order.
[2] The basis weight P of the paper material is 30 to 300 g / m ² , and the total coating amount C of the first clay coat layer and the second clay coat layer is 10 to 60 g / m ² . 1] The adhesive sheet.
[3] Ratio of the basis weight P (g / m ² ) of the paper material to the total coating amount C (g / m ² ) of the first clay coat layer and the second clay coat layer [P / C]. The pressure-sensitive adhesive sheet according to the above [1] or [2], wherein the pressure is 0.2 to 0.7.
[4] In any one of the above [1] to [3], the surface resistivity measured from the surface side of the moisture-proof layer is 1.0 × 10 ⁹ to 1.0 × 10 ¹³ Ω / □. The described adhesive sheet.
[5] The adhesive sheet according to any one of the above [1] to [4], which is used for printing with a laser printer.

The pressure-sensitive adhesive sheet of the present invention has a surface base material made of a synthetic resin film and a release material using a paper material, and curls due to heating are effectively suppressed immediately after heating and after cooling. Further, the fixing property of the toner is also good.

It is a schematic sectional drawing of the pressure-sensitive adhesive sheet which shows an example of the pressure-sensitive adhesive sheet of this invention.

[Structure of Adhesive Sheet of the Present Invention]
FIG. 1 is a schematic cross-sectional view of the pressure-sensitive adhesive sheet showing an example of the pressure-sensitive adhesive sheet of the present invention.
The pressure-sensitive adhesive sheet of the present invention has the pressure-sensitive adhesive layer 20 and the surface base material 30 on the release agent layer 13 of the release material 10 in this order, as in the pressure-sensitive adhesive sheet 1 shown in FIG.
The release material of the pressure-sensitive adhesive sheet of the present invention has a first clay coat layer 121 and a second clay coat layer 122 on both sides of the paper material 11, respectively, as in the release material 10 shown in FIG. The release agent layer 13 is provided on the clay coat layer 121, and the moisture-proof layer 14 is provided on the second clay coat layer 122.

In one aspect of the present invention, as in the pressure-sensitive adhesive sheet 1 shown in FIG. 1, the above-mentioned layers may be directly laminated, or an arbitrary layer may be provided between the two layers.
For example, as the pressure-sensitive adhesive sheet of one aspect of the present invention, a primer layer is provided between the pressure-sensitive adhesive layer 20 and the surface base material 30 in order to improve the interlayer adhesion between the pressure-sensitive adhesive layer 20 and the surface base material 30. May be.
Further, a print receiving layer may be further provided on the surface 30a of the surface base material 30 on the opposite side of the pressure-sensitive adhesive layer 20 in order to facilitate fixing of the toner during printing using a laser printer. ..
Hereinafter, each layer of the release material, the pressure-sensitive adhesive layer, and the surface base material constituting the pressure-sensitive adhesive sheet of the present invention will be described.

[Release material]
The release material used in the pressure-sensitive adhesive sheet of the present invention has a first clay coat layer and a second clay coat layer on both sides of the paper material, respectively, and has a release agent layer on the first clay coat layer and a second clay. A moisture-proof layer 14 is provided on the coat layer.

As described above, an adhesive sheet having a surface base material made of a synthetic resin film and a release material using a paper material causes extremely large curls when printed with a laser printer.
As a result of the present inventors, in an adhesive sheet having a surface base material made of a synthetic resin film and a release material using a paper material, two clay coat layers are provided on both sides of the paper material as the release material. , It has been found that an adhesive sheet that effectively suppresses the generation of curl can be obtained.
The release material having such a structure can increase the rigidity of the release material due to the presence of clay contained in the clay coat layer. As a result, by using the release material, the release material side resists the stress caused by the dimensional difference between the surface base material and the release material, which slows down the curling speed of the adhesive sheet and promotes stress relaxation in the meantime. Therefore, it is considered that the absolute amount of curl can be reduced.

Further, the release material used in the present invention has a release agent layer on the first clay coat layer.
In the pressure-sensitive adhesive sheet of the present invention, the release agent layer is directly laminated with the pressure-sensitive adhesive layer, and when the pressure-sensitive adhesive sheet is used, it is peeled off between the release agent layer and the pressure-sensitive adhesive layer.

The release material used in one aspect of the present invention may have a sealing layer between the first clay coat layer and the release material layer.
However, when the release agent layer is formed by applying a release agent on the first clay coat layer, the first clay coat layer serves as a sealing layer for preventing the release agent from seeping into the paper material. Also bears.
Therefore, in the release material used in one aspect of the present invention, it is not necessary to provide the above-mentioned sealing layer, so it is preferable to have a structure in which the release agent layer is directly laminated on the first clay coat layer.

Further, the release material used in the present invention has a moisture-proof layer on the second clay coat layer.
When the pressure-sensitive adhesive sheet of the present invention is printed by a laser printer, the heat transfer roll comes into contact with the moisture-proof layer 14 side of the pressure-sensitive adhesive sheet to heat the pressure-sensitive adhesive sheet.
In the cooling process from a high temperature state immediately after printing, the release material side having the paper material is more likely to absorb water vapor than the surface substrate side made of the synthetic resin film. This is due to the difference in materials that paper materials absorb water vapor more easily than synthetic resin films. As a result, the release material side having the paper material rapidly absorbs moisture and stretches, and heat shrinkage of the synthetic resin film on the surface base material side occurs, resulting in a new dimensional difference between the release material side and the surface base material side. There may be an adverse effect such as curling after cooling.

On the other hand, in the pressure-sensitive adhesive sheet of the present invention, by providing a moisture-proof layer on the release material side having the paper material, the moisture absorption rate of water vapor is suppressed in the cooling process from the high temperature state immediately after printing, and the release material side and the release material side. The dimensional difference from the surface base material side is suppressed. As a result, even after the adhesive sheet after printing is left for a while and cooled, the generation of curl can be effectively suppressed as in the state immediately after printing.

Further, the release material of the adhesive sheet of the present invention has a paper material, a first clay coat layer and a second clay coat layer for sandwiching the paper material, and further has a moisture-proof layer on the second clay coat layer. Since it is not composed of a material having only insulating properties like a synthetic resin film, it is easy to adjust the surface resistivity to a low level. As a result, the charge on the surface substrate side can be suppressed, so that the fixing property of the toner can be improved.
In the release material using synthetic paper, it is necessary to provide an antistatic layer in order to improve the fixability of the toner. On the other hand, the release material used in the present invention may also be provided with an antistatic layer, but from the above viewpoint, it is less necessary to provide an antistatic layer.

In the pressure-sensitive adhesive sheet of one aspect of the present invention, the surface resistivity measured from the surface side of the moisture-proof layer is preferably 1.0 × 10 ⁹ to 1.0 × 10 ¹³ Ω / □.
When the surface resistivity is 1.0 × ¹⁰⁹ Ω / □ or more, the fixing property of the toner is good.
On the other hand, when the surface resistivity is 1.0 × 10 ¹³ Ω / □ or less, the scattering of toner can be prevented.

In the pressure-sensitive adhesive sheet of one aspect of the present invention, the volume resistivity measured from the surface side of the moisture-proof layer is preferably 1.0 × 10 ¹⁰ to 1.0 × 10 ¹⁴ Ω · cm.
In this specification, the surface resistivity and the volume resistivity mean the values measured based on the four-terminal method specified in JIS K7194.

<Paper material>
The paper material contained in the release material used in the present invention is mainly formed from plant fibers (pulp), and is distinguished from synthetic paper in that respect.
Examples of the paper fiber constituting the paper material include wood pulp such as NBKP and LBKP, non-wood pulp such as reeds, bamboo, kenaf, bagasse and linter, and recycled pulp such as used paper and DIP.

The paper material used in one aspect of the present invention may contain an internal filling agent or an internal chemical.
Examples of the internal filler include an internal filler such as an inorganic filler used in general paper production such as calcium carbonate, titanium dioxide, aluminum hydroxide, silica, talc, and clay.
These internal fillers may be used alone or in combination of two or more.

Examples of the internal chemicals include rosin size, emulsion rosin, sizing agents such as AKD (alkyl ketene dimer); fixing agents such as aluminum sulfate band and polyethyleneimine; paper strength agents such as acrylic amide and cationized starch; melamine and epi. Wet paper force agents such as chlorohydrin; dyes; etc. may be mentioned.

The paper material used in one aspect of the present invention can be produced by mixing these paper fibers, an internal filler, and an internal chemical with a long net paper machine, a circular rope paper machine, or the like.
Examples of the paper material used in one aspect of the present invention include high-quality paper, kraft paper, and glassine paper.
Further, the paper material may be a single layer or a laminated body of two or more.

The basis weight of the paper material is appropriately set according to the intended use, but is preferably 30 to 300 g / m ² , more preferably 40 to 200 g / m ² , and further preferably 50 to 150 g / m ² .
The thickness of the paper material as a raw material is preferably 5 to 1000 μm, more preferably 10 to 500 μm, still more preferably 12 to 250 μm, and even more preferably 15 to 150 μm.

<1st clay coat layer, 2nd clay coat layer>
The clay coat composition for forming the first clay coat layer and the second clay coat layer (hereinafter collectively referred to as “clay coat layer”) contained in the release material used in the present invention is a composition containing clay and a binder resin. It is preferable to have.

As the clay contained in the clay coat composition, any clay generally called clay or clay can be used, and for example, kaolin, talc, bentonite, smectite, vermiculite, mica, chlorite, chlorite, etc. Examples include gailome clay and halloysite.
These clays may be used alone or in combination of two or more.

The content of clay in the clay coat composition is preferably relative to the total solid content (100% by mass) of the clay coat composition from the viewpoint of making an adhesive sheet capable of more effectively suppressing the generation of curl. It is 40 to 95% by mass, more preferably 60 to 90% by mass, and further preferably 70 to 85% by mass.

Examples of the binder resin contained in the clay coat composition include a styrene-butadiene copolymer, an ethylene-vinyl chloride copolymer, a methyl methacrylate-butadiene copolymer, an ethylene-vinyl acetate copolymer, and a (meth) acrylic acid. Emulsions of copolymers such as ester copolymers; water-soluble resins such as casein, dextrin, starch, oxidized starch, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol and the like can be mentioned.
These binder resins may be used alone or in combination of two or more.

In one aspect of the present invention, the binder resin preferably contains both a styrene-butadiene copolymer emulsion and a water-soluble resin, and styrene, from the viewpoint of obtaining a pressure-sensitive adhesive sheet capable of more effectively suppressing the generation of curl. -It is more preferable to contain both a butadiene copolymer emulsion and polyvinyl alcohol.

The content of the binder resin in the clay coat composition is preferably 5 to 60% by mass, more preferably 10 to 40% by mass, still more preferably, based on the total solid content (100% by mass) of the clay coat composition. Is 15 to 30% by mass.

The clay coat composition may contain other additives in addition to the clay and the binder resin.
Examples of other additives include pigments, pigment dispersants, defoamers, foam inhibitors, viscosity modifiers, lubricants, water resistant agents, water retention agents, coloring materials and the like.

Further, it is preferable that one or both of the first clay coat layer and the second clay coat layer are subjected to super calendar treatment on the coated surface coated with the layer to smooth the surface. By performing the super calendar processing, the paper material becomes tighter, and the effect of sealing and the effect of rigidity are improved.

In one aspect of the present invention, the coating amount of the first clay coat layer is preferably 3 g / m ² or more, more preferably 5 to 30 g / m ² , and further preferably 10 to 25 g / m ² .

In one aspect of the present invention, the coating amount of the second clay coat layer is preferably 3 g / m ² or more, more preferably 5 to 30 g / m ² , and further preferably 10 to 25 g / m ² .

In the release material used in one aspect of the present invention, when the basis weight of the paper material is in the range of 30 to 300 g / m ² , the total coating amount of the first clay coat layer and the second clay coat layer is curl generation. From the viewpoint of making an adhesive sheet capable of effectively suppressing the above, it is preferably 10 to 60 g / m ² , more preferably 20 to 50 g / m ² , and further preferably 25 to 40 g / m ² .

Further, in the release material used in one aspect of the present invention, from the viewpoint of making an adhesive sheet capable of more effectively suppressing the generation of curl, the first clay coat layer with respect to the basis weight P (g / m ² ) of the paper material. The ratio [C / P] of the total coating amount C (g / m ² ) of the second clay coat layer is preferably 0.2 to 0.7, more preferably 0.25 to 0.6, and even more preferably. It is 0.3 to 0.5.

<Release layer>
The release agent layer of the release material used in the present invention can be formed from a release agent composition containing a releaseable component on the first clay coat layer.
Examples of the peelable component contained in the release agent composition which is a material for forming the release agent layer include alkyd resin, silicone resin, fluororesin, unsaturated polyester resin, polyolefin resin, waxes and the like. Be done.
These peeling components may be used alone or in combination of two or more.
Among the peelable components contained in these release agent compositions, a silicone-based resin is preferable from the viewpoint of forming a release agent layer having heat resistance.

The thickness of the release agent layer is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm, and further preferably 0.1 to 2 μm from the viewpoint of peelability and curability of the coating film.

<Damp proof layer>
The moisture-proof layer of the release material used in the present invention is preferably formed from a composition for forming a moisture-proof layer containing a water-dispersible resin that functions as a moisture-proof agent.
Examples of the water-dispersible resin include polyolefin resins (polyethylene, polypropylene, etc.), vinyl chloride resins, styrene resins, styrene-butadiene copolymers, acrylonitrile-styrene copolymers, acrylonitrile-butadiene copolymers, ABS resins, and the like. AAS resin, AES resin, vinylidene chloride resin, polyurethane resin, poly-4-methylpentene-1 resin, polybutene-1 resin, vinylidene fluoride resin, vinyl fluoride resin, fluororesin, polycarbonate resin, polyamide resin, acetal resin, Examples thereof include polyphenylene oxide resin, polyester resin (polyethylene terephthalate, polybutylene terephthalate, etc.), polyphenylene sulfide resin, polyimide resin, polysulfone resin, polyether sulfone resin, aromatic polyester resin, polyallylate resin, and modified products thereof. These resins are preferably emulsions.
These water-dispersible resins may be used alone or in combination of two or more.

Among these, as the water-dispersible resin used in one embodiment of the present invention, an emulsion of a resin selected from a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, and vinylidene chloride is preferable.

In addition to the above-mentioned water-dispersible resin, the composition for forming a moisture-proof layer includes wax components such as paraffin-based wax and polyethylene-based wax; starch; oxidized starch, etherified starch, dialdehydeized starch, esterified starch and the like. Modified starch; may contain polyvinyl alcohol and the like.

From the viewpoint of forming a moisture-proof layer having further improved moisture-proof properties, the composition for forming a moisture-proof layer may further contain an inorganic pigment.
Examples of the inorganic pigment include calcium carbonate, magnesium carbonate, silicon dioxide, titanium dioxide, zinc oxide, aluminum oxide, magnesium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, zinc sulfate, kaolin, talc, and calcined kaolin. Examples include lithopone and sachin white.
These inorganic pigments may be used alone or in combination of two or more.

Further, in the pressure-sensitive adhesive sheet of one aspect of the present invention, the composition for forming a moisture-proof layer may further contain a thermosetting resin from the viewpoint of forming a moisture-proof layer having improved film strength and heat resistance.
Examples of the thermosetting resin include amino resins such as melamine resins, polyvalent epoxy resins, aldehyde resins, polyvalent isocyanate resins, and phenol resins.
These thermosetting resins may be used alone or in combination of two or more.

The coating amount of the moisture-proof layer is preferably 1 to 10 g / m ² , more preferably 2 to 8 g / m ² , and further preferably 3 to 6 g / m ² .

Further, since the moisture-proof layer is formed from the composition containing the above-mentioned water-dispersible resin, blocking may occur in a wet state.
Therefore, the release material used in one aspect of the present invention may be provided with a blocking prevention layer on the surface of the moisture-proof layer opposite to the second clay coat layer.
Examples of the material for forming the blocking prevention layer include styrene acrylic resin and the like.

[Adhesive layer]
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention can be formed from a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive resin.
The adhesive resin is appropriately selected depending on the intended use, and for example, an acrylic resin, a urethane resin, a rubber resin, an olefin resin, a silicone resin, and these resins have a polymerizable functional group. Examples include energy ray-curable resins.
These adhesive resins may be used alone or in combination of two or more.

Further, the pressure-sensitive adhesive composition which is a material for forming the pressure-sensitive adhesive layer may contain an additive for a pressure-sensitive adhesive depending on the type of the pressure-sensitive adhesive resin and the use of the pressure-sensitive adhesive sheet.
Examples of the adhesive additive include a cross-linking agent, a tackifier, a filler, an antioxidant, a heat stabilizer, an ultraviolet absorber, a light stabilizer, a colorant, a flame retardant, a thickener, and an antistatic agent. , Polymerization initiators, curing aids and the like.

The thickness of the pressure-sensitive adhesive layer is appropriately set depending on the intended use, but is preferably 1 to 100 μm, more preferably 5 to 80 μm, and even more preferably 10 to 60 μm.

[Surface base material]
The surface base material of the pressure-sensitive adhesive sheet of the present invention may be a synthetic resin film, preferably synthetic paper.

The synthetic paper is composed of synthetic fibers made of resins such as polypropylene, polystyrene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, and polyamide. Things etc. can be mentioned.
As the synthetic paper used in the present invention, a commercially available product may be used, for example, "Crisper (registered trademark)" (manufactured by Toyo Spinning Co., Ltd., void-containing polyester synthetic paper), "Yupo (registered trademark)". (Made by Yupo Corporation, void-containing polypropylene-based synthetic paper), "Laser Peach" (manufactured by Nisshinbo Paper Products Co., Ltd., polyester-based synthetic paper) and the like can be mentioned.
Among these, polyester-based synthetic paper is more preferable as the surface base material.

Examples of the resin constituting the synthetic resin film other than the synthetic paper used for the surface substrate include polyolefin resins such as polyethylene and polypropylene; polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene. -Vinyl-based resins such as vinyl alcohol copolymers; polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; polyurethane, acrylic-modified polyurethane Such as urethane resin; polymethylpentene; polysulfone; polyether ether ketone; polyether sulfone; polyphenylene sulfide; polyimide resin such as polyetherimide and polyimide; polyamide resin; acrylic resin; fluororesin and the like can be mentioned.

The synthetic resin film may further contain various additives such as an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a slip agent, an antiblocking agent, and a colorant.
Further, the surface base material may be a single layer or a plurality of layers in which two or more are laminated.

In the surface base material used in one aspect of the present invention, the surface of the synthetic resin film constituting the surface base material is surface-treated by an oxidation method, an unevenness method, or the like from the viewpoint of improving the adhesion to the pressure-sensitive adhesive layer. , Or a primer layer may be provided.
Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), hot air treatment, ozone and ultraviolet irradiation treatment and the like.
Examples of the unevenness method include a sandblast method and a solvent treatment method.

The thickness of the surface base material is appropriately set depending on the intended use, but is preferably 5 to 1000 μm, more preferably 10 to 700 μm, still more preferably 20 to 500 μm, and even more preferably 30 to 300 μm.

In the pressure-sensitive adhesive sheet of one aspect of the present invention, from the viewpoint of improving the fixing of toner, ink, etc. when printing using a laser printer or the like, the surface on the surface opposite to the pressure-sensitive adhesive layer of the surface substrate. In addition, it may have a print receiving layer.

[Manufacturing method of adhesive sheet]
The method for producing the pressure-sensitive adhesive sheet of the present invention is not particularly limited, and examples thereof include methods having the following steps (1) to (5).
-Step (1): A step of forming a first clay coat layer on one side of a paper material.
-Step (2): A step of forming a release agent layer on the first clay coat layer.
-Step (3): A step of forming a second clay coat layer on the other side of the paper material.
-Step (4): A step of forming a moisture-proof layer on the second clay coat layer.
Step (5): A step of forming a pressure-sensitive adhesive layer on the release agent layer and laminating a surface base material on the exposed surface of the pressure-sensitive adhesive layer.

In the above manufacturing method, the order of the steps (1) to (5) is not limited, but it is preferable to go through the step (5) after producing the release material through the steps (1) to (4).
In the above aspect, the order of the steps (1) to (4) for producing the release material does not matter.

For example, the step (3) may be performed after the step (1) to simultaneously form the first clay coat layer and the second clay coat layer on both sides of the paper material, and then the steps (2) and (4) may be performed. ..
The steps (1) and (3) may be performed simultaneously in one step, and the first clay coat layer and the second clay coat layer may be formed on both sides of the paper material at the same time.
Similarly, steps (2) and (4) may be performed simultaneously in one step to form the release agent layer and the moisture-proof layer at the same time.

As a method for forming each layer in each step, it can be formed by applying a composition which is a material for forming each layer to form a coating film, and drying the coating film.
In addition to the components contained in each layer, a solvent may be added to the composition, if necessary, in the form of a solution from the viewpoint of improving coatability.

As the coating method, a known method can be applied, and examples thereof include a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, and a gravure coating method.

[Characteristics of adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention is suitable for applications involving heating as described above, but is particularly preferably used for printing with a laser printer.
That is, the adhesive sheet of the present invention can effectively suppress the generation of curl even when printed by a laser printer, immediately after printing and after being left to cool. Further, since the surface resistivity on the release material side is adjusted to be low and the generation of static electricity can be suppressed, the fixing property of the toner on the surface substrate side, which is the printed surface, is also good.

The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following examples.

The forming materials for each layer used in the following examples and comparative examples are as follows.
<Paper material>
Woodfree paper (manufactured by Nippon Paper Industries, Ltd., product name "Joushitsu AB-EC85G"), basis weight = 85 g / m ² , thickness as raw material = 134 μm.
<Surface base material>
Polyester-based synthetic paper (manufactured by Toyobo Co., Ltd., product name "Crisper (registered trademark) 7911"), thickness = 50 μm.

<Release composition>
To 100 parts by mass of a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KS-847"), 1 part by mass of a platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., product name "PL-50T") is added, and toluene is added. A composition prepared by diluting with a solid content concentration of 10% by mass.
<Clay coat composition (material for forming the first clay coat layer and the second clay coat layer)>
80 parts by mass (solid content equivalent, the same applies hereinafter) of Kuraray Clay 2nd grade (manufactured by Imeris Mineral Japan Co., Ltd., product name "CCS") as a clay component, and a styrene-butadiene copolymer (Nippon A & L Co., Ltd.) as a binder resin component. 9 parts by mass of product name "Smart Tech SN-307R"), 9 parts by mass of oxidized starch (manufactured by Nippon Starch Industry Co., Ltd., product name "Sanas 350"), and polyvinyl alcohol (manufactured by Kuraray Co., Ltd., product name " Kuraray Poval PVA-117 ") A composition prepared by adding 2 parts by mass and further diluting with water to a solid content concentration of 36% by mass.
<Composition for forming a moisture-proof layer>
A composition containing a vinylidene chloride resin (manufactured by Asahi Kasei Corporation, product name "Saran Latex L-411A").
<Composition for forming an anti-blocking layer>
A composition containing a styrene acrylic resin (manufactured by Mitsui Chemicals, Inc., product name "Bonlon S-1318NF").

Example 1
(1) Preparation of release material The above clay coat composition is applied to both sides of the above paper material using a double-sided coater to form a coating film, and both coating films are dried at 150 ° C. for 20 seconds. In both cases, a first clay coat layer and a second clay coat layer having a coating amount of 16 g / m ² were formed. Subsequently, the obtained sheet was subjected to super calendar processing by passing it through a metal multi-stage roll to prepare a double-sided clay coated paper having a layer thickness of 130 μm.
Next, the above release agent composition was applied onto the first clay coat layer to form a coating film, and the coating film was dried at 150 ° C. for 20 seconds to form a release agent layer having a thickness of 1 μm.
Further, the above-mentioned composition for forming a moisture-proof layer is applied onto the second clay coat layer to form a coating film, and the coating film is dried at 100 ° C. for 1 minute to form a moisture-proof layer having a coating amount of 4 g / m ² . Formed. Subsequently, the above composition for forming an anti-blocking layer is applied onto the moisture-proof layer to form a coating film, and the coating film is dried at 100 ° C. for 30 seconds to prevent a blocking layer having a coating film amount of 1 g / m ² . Was formed to prepare a release material (1).
(2) Preparation of Adhesive Sheet Acrylic adhesive (manufactured by Lintec Corporation, product name "PAT1") is applied on the release agent layer of the prepared release material (1) to form a coating film, and the coating film is formed. It was dried at 100 ° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 20 μm. Then, the above-mentioned surface base material was laminated on the surface of the pressure-sensitive adhesive layer to obtain a pressure-sensitive adhesive sheet (I).

Comparative Example 1
The release material (2) was produced in the same manner as in Example 1 except that the moisture-proof layer and the blocking prevention layer were not formed.
Then, using the release material (2), an adhesive sheet (II) was obtained in the same manner as in Example 1.

Comparative Example 2
A release material (3) was produced in the same manner as in Example 1 except that a moisture-proof layer and subsequently a blocking prevention layer were formed on one side of the paper material without forming the second clay coat layer.
Then, using the release material (3), an adhesive sheet (III) was obtained in the same manner as in Example 1.

Comparative Example 3
As the release material (4), a polyester-based synthetic paper (manufactured by Toyobo Co., Ltd., product name "Crisper K7245", thickness 50 μm) having a release agent layer on one side and an antistatic layer on the other side was used. An adhesive sheet (IV) was obtained in the same manner as in Example 1.

Comparative Example 4
A release material (5) was obtained in the same manner as in Example 1 except that the second clay coat layer, the moisture-proof layer, and the blocking prevention layer were not formed.
Then, using the release material (5), an adhesive sheet (V) was obtained in the same manner as in Example 1.

Comparative Example 5
As the release material (6), a release material (manufactured by Lintec Corporation, product name "8E") made of single-sided laminated paper having a release agent layer is used to obtain an adhesive sheet (VI) in the same manner as in Example 1. rice field.

Comparative Example 6
The above composition for forming a moisture-proof layer is applied to the surface of the release material (6) opposite to the release agent layer to form a coating film, and the coating film is dried at 100 ° C. for 1 minute to apply a coating film of 4 g / m. A moisture-proof layer of ² was formed. Subsequently, the above composition for forming an anti-blocking layer is applied onto the moisture-proof layer to form a coating film, and the coating film is dried at 100 ° C. for 30 seconds to prevent a blocking layer having a coating film amount of 1 g / m ² . Was formed to prepare a release material (7).
Then, using the release material (7), an adhesive sheet (VII) was obtained in the same manner as in Example 1.

Comparative Example 7
As the release material (8), an adhesive sheet (manufactured by Lintec Corporation, product name "7K white") having a release agent layer on one surface of the glassine paper is used in the same manner as in Example 1 (adhesive sheet). VIII) was obtained.

Comparative Example 8
The above composition for forming a moisture-proof layer is applied to the surface of the release material (8) opposite to the release agent layer to form a coating film, and the coating film is dried at 100 ° C. for 1 minute to apply a coating film of 4 g / g. A moisture-proof layer of m ² was formed. Subsequently, the above composition for forming an anti-blocking layer is applied onto the moisture-proof layer to form a coating film, and the coating film is dried at 100 ° C. for 30 seconds to prevent a blocking layer having a coating film amount of 1 g / m ² . Was formed to prepare a release material (9).
Then, using the release material (9), an adhesive sheet (IX) was obtained in the same manner as in Example 1.

Table 1 summarizes the configurations of the release materials (1) to (9) contained in the pressure-sensitive adhesive sheets (I) to (IX) produced as described above.
In addition, the following evaluations and measurements were performed on the adhesive sheets (I) to (IX). These results are shown in Table 2.

(1) Evaluation Method of Curling Suppression Effect of Adhesive Sheet The produced adhesive sheet was set to A4 size and color-printed using a laser printer (manufactured by Canon Inc., product name "LBP-9600").
Then, within 30 seconds immediately after printing (immediately after printing), 2 minutes after printing (after air cooling), and after standing for 24 hours in an environment of 23 ° C. and 50% RH (relative humidity) after printing (after humidity control). The warped surface side of the adhesive sheet was placed on a flat table, the heights of the adhesive sheets from the four corners of the table were measured, and the maximum value of the curl height was obtained. The maximum value of the curl height shown in Table 1 is the maximum value when the curl state is a positive curl (curl in which the surface base material is on the outside of the warped surface and the release material is on the inside of the warped surface). In the case of reverse curl (curl in which the surface base material is inside the warped surface and the release material is outside the warped surface), the code of the maximum value is marked as minus.
Further, based on the maximum value of the curl height (maximum value of the absolute value), the curl suppressing effect was evaluated according to the following criteria.
(Curl evaluation immediately after printing and after air cooling)
5: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 0 mm or more and less than 15 mm.
-4: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 15 mm or more and less than 30 mm.
3: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 30 mm or more and less than 50 mm.
-2: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 50 mm or more and less than 70 mm.
1: The maximum value of curl height (absolute value of the numerical values in Table 1) is 70 mm or more.
(Curl evaluation after humidity control)
5: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 0 mm or more and less than 5 mm.
-4: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 5 mm or more and less than 10 mm.
3: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 10 mm or more and less than 20 mm.
-2: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 20 mm or more and less than 30 mm.
1: The maximum value of curl height (absolute value of the numerical values in Table 1) is 30 mm or more.

(2) Surface resistivity and volume resistivity Based on the four-terminal method specified in JIS K7194, each adhesive sheet is used using the resistivity meter "Loresta GP MCP-T600" (product name, manufactured by Mitsubishi Chemical Corporation). The surface resistivity and volume resistivity were measured from the release material side of.

(3) Evaluation Method of Printability of Adhesive Sheet The produced adhesive sheet was color-printed with a predetermined standard image using a laser printer (manufactured by Canon Inc., product name "LBP-9600").
If the toner is scattered immediately after printing and the image is bleeding, it is evaluated as "x", and if the toner is fixed to the surface substrate without any problem and the standard image is obtained, it is evaluated as "○". evaluated.

From Table 2, the adhesive sheet (I) produced in Example 1 was compared with the adhesive sheets (II) to (IX) produced in Comparative Examples 1 to 8 immediately after printing, after air cooling, or after humidity control. As a result, an excellent curl suppressing effect was exhibited. In addition, the adhesive sheet (I) has good printability and excellent toner fixability.

1 Adhesive sheet 10 Peeling material 11 Paper material 121 1st clay coat layer 122 2nd clay coat layer 13 Peeling agent layer 14 Moisture-proof layer 20 Adhesive layer 30 Surface base material 30a Surface

Claims (5)

A first clay coat layer and a second clay coat layer are provided on both sides of the paper material, a release agent layer is directly laminated on the first clay coat layer, and a moisture-proof layer is provided on the second clay coat layer. With the release material,
A pressure-sensitive adhesive layer and a surface base material made of a synthetic resin film are provided on the release agent layer of the release material in this order .
The ratio [C / P] of the total coating amount C (g / m ² ) of the first clay coat layer and the second clay coat layer to the basis weight P (g / m ² ) of the paper material is 0. 38-0.7,
A pressure-sensitive adhesive sheet in which the moisture-proof layer is formed of a moisture-proof layer forming composition containing an aqueous dispersion resin selected from a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, and vinylidene chloride . The adhesive according to claim 1, wherein the basis weight of the paper material is 30 to 300 g / m ² , and the total coating amount of the first clay coat layer and the second clay coat layer is 10 to 60 g / m ² . Sheet. The pressure-sensitive adhesive sheet according to claim 1 or 2 , wherein the surface resistivity measured from the surface side of the moisture-proof layer is 1.0 × 10 ⁹ to 1.0 × 10 ¹³ Ω / □. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, which has a blocking prevention layer on the surface of the moisture-proof layer opposite to the second clay coat layer. The adhesive sheet according to any one of claims 1 to 4 , which is used for printing with a laser printer.

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