JP6954574B2 - 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 labels, 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 base material, an adhesive layer, and a release material are laminated in this order. Paper materials are often used as the surface base material for general-purpose label adhesive sheets, but synthetic resin films may be used as the surface base material in order to enhance the appearance and texture of the paper materials. 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 give the surface base material a texture close to that of paper and also to have the above-mentioned properties.

By the way, an 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 an adhesive sheet printing means using a synthetic resin film as a surface base material can print in the same manner as plain paper, and its application to a laser printer is desired.
Further, the release material used for the adhesive sheet for general-purpose labels 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 uses a synthetic resin film or synthetic paper as a support, and a pigment is provided on the synthetic resin film or synthetic paper. An adhesive sheet for a page printer for PPC, which has a coating layer containing an adhesive and a conductive agent and has an adjusted smoother smoothness and surface charge amount of the coating 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 Unexamined Patent Publication No. 6-286042

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 curls are generated.
That is, the heat of the thermal transfer roll that passes when fixing the toner to the surface base material causes the paper material of the release material to shrink due to drying, resulting in positive curl (the surface base material 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 the synthetic resin film undergoes thermal shrinkage, causing reverse curl (opposite to normal curl).
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 a synthetic resin film is used as the surface base material, in order to suppress the occurrence of curl after printing, the release base material constituting the release material also has the same level of dimensional change in thermal history as the surface base material. A synthetic resin film such as synthetic paper is selected, and it is common to avoid using a paper material whose degree of dimensional change due to heat is different from that of the surface base material.
However, since the release material using the 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.

The pressure-sensitive adhesive sheet described in Patent Document 1 uses a synthetic resin film or synthetic paper as a surface base material, but studies have been conducted on suppressing curl that may occur when a release material using a paper material is used. Not broken.

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

The present inventor has a polyethylene layer and 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. 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 clay coat layer.

That is, the present invention provides the following [1] to [5].
[1] A release material having a clay coat layer on the first surface and a polyethylene layer on the second surface of the paper material, a release agent layer on the polyethylene layer, and a moisture-proof layer on the clay coat layer. When,
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 ratio [P / R] of the basis weight P (g / m ² ) of the paper material to the basis weight R (g / m ^{2) of the release material is 0.58 to 0.92.} The adhesive sheet according to [1].
[3] The adhesive sheet according to the above [1] or [2], wherein the paper material has a basis weight of 30 to 300 g / m ² , and the polyethylene layer has a basis weight of 3 g / m ^{2 or more.}
[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 fixability of the toner is also good.

It is a schematic cross-sectional view 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 clay coat layer 12b on the first surface and a polyethylene layer 12a on the second surface of the paper material 11, as in the release material 10 shown in FIG. A release agent layer 13 is provided on the polyethylene layer 12a, and a moisture-proof layer 14 is provided on the clay coat layer 12b.

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, but 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 clay coat layer on the first surface and a polyethylene layer on the second surface of the paper material, has a release agent layer on the polyethylene layer, and is on the clay coat layer. Has a moisture-proof 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. In an adhesive sheet having a surface base material made of a synthetic resin film and a release material using a paper material, the present inventors use a clay coat layer and a paper material on the first surface in contact with the moisture-proof layer as the release material. As a result of providing the polyethylene layer on the second surface in contact with the release agent layer, it has been found that the pressure-sensitive adhesive sheet can effectively suppress the generation of curl.
Due to the presence of the polyethylene layer and the clay contained in the clay coat layer, the release material having such a structure can increase the rigidity of the release agent by restraining the elasticity of the paper material from both sides. 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, so that the curling speed of the adhesive sheet is slowed down, and stress relaxation proceeds during that time. 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 polyethylene 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.

Further, the release material used in the present invention has a moisture-proof layer on the clay coat layer.
When the pressure-sensitive adhesive sheet of the present invention is printed with a laser printer, the heat transfer roll comes into contact with the moisture-proof layer 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 absorbs water vapor more easily than the surface base material 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 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 occurrence of curl can be effectively suppressed as in the state immediately after printing.

Further, the release material of the pressure-sensitive adhesive sheet of the present invention has a paper material, a polyethylene layer and a clay coat layer for sandwiching the paper material, and further has a moisture-proof layer on the clay coat layer. Since it is not composed only of such an insulating material, the surface resistivity can be easily adjusted to be low.
As a result, the charge on the surface base material side can be suppressed, so that the fixability of the toner can be improved.

Further, in the release material of the pressure-sensitive adhesive sheet of the present invention, the ratio [P / R] of the basis weight P (g / m ^{2 ) of the paper material to the basis weight R (g / m 2) of the release material is mass.} The ratio is preferably 0.58 to 0.92, more preferably 0.62 to 0.81. When the ratio is 0.92 or less, the influence of elasticity due to drying / moisture absorption by the pulp in the paper material is less likely to appear, and when the ratio is 0.58 or more, the strength of the adhesive sheet is maintained. It becomes difficult to curl according to the dimensional change of synthetic paper. In this way, even if printing by a laser printer is performed on the adhesive sheet, the amount of curling can be suppressed.
The basis weight R of release material, from the viewpoint of curability of the peelable and film, is preferably 10 to 1000 g / ^{m 2,} more preferably 50 to 500 g / ^{m 2,} more preferably 80 to 200 g / ^{m 2} ..

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 Ω / □ to 1.0 × 10 ¹³ Ω / □.
If the surface resistivity of 1.0 × 10 ⁹ Ω / □ or more, fixability of the toner becomes 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 Ω · cm 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: 1994.

<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 filler 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 supplements 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 strength 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 depending on the application, preferably 30~300g / ^{m 2,} more preferably 40~200g / ^{m 2,} more preferably from 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.

<Polyethylene layer>
The polyethylene resin used for the polyethylene layer is a polymer mainly composed of a structural unit derived from an ethylene monomer. Here, the "polymer mainly composed of a structural unit derived from an ethylene monomer" means that the structural unit contained most in the polymer is a structural unit derived from an ethylene monomer. ..
The content of the constituent units derived from the ethylene monomer in the polyethylene resin is preferably 95 mol% or more with respect to all the constituent units of the polyethylene resin. The polyethylene resin may contain one or more olefin monomers other than the ethylene monomer.
The polyethylene resin used for the polyethylene layer includes ethylene homopolymer; at least of ethylene and α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene and 1-octene. Copolymer resin with one type (here, α-olefin is preferably more than 0 mol% and 5 mol% or less in the monomer); ethylene and carbon atom, oxygen atom, and hydrogen as functional groups. Examples thereof include a polymer with a non-olefin monomer having only an atom (here, the non-olefin monomer is preferably more than 0 mol% and 5 mol% or less in the monomer).

The polyethylene resin is (branched) low density polyethylene resin (LDPE, density: 910 kg / m ³ or more and less than 930 kg / m ³ ), linear low density polyethylene resin (LLDPE, density: 910 kg / m ³ or more and 930 kg / m ^3). below), medium-density polyethylene resin (MDPE, density: 930 kg / ^{m 3} or more 942kg / ^m less than ^3), very low density polyethylene resin (VLDPE, density: 880 kg / ^{m 3} or more 910 kg / ^m less than ^3), high density polyethylene resin It may be any of (HDPE, density: 942 kg / m ^{3 or more).} Further, it may be a mixture of the above polyethylene resins.

The molecular weight of the polyethylene resin is not particularly limited, but the melt flow rate (MFR) (JIS K7210-1: 2014, test temperature 190 ° C., nominal load 2.16 kg) is between 0.03 and 40 g / 10 minutes. Those having extrusion suitability are preferable.

In one aspect of the present invention, the basis weight of the polyethylene layer, preferably 3 g / ^{m 2} or more, more preferably 5 to 30 g / ^{m 2,} more preferably from 10 to 25 g / ^{m 2.}

<Clay coat layer>
The clay coat composition for forming the clay coat layer of the release material used in the present invention is preferably a composition containing clay and a binder resin.

As the clay contained in the clay coat composition, any clay generally called clay or clay can be used. 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 forming an adhesive sheet capable of more effectively suppressing the generation of curls. It is 40 to 95% by mass, more preferably 60 to 90% by mass, and even more 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 forming 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, antifoaming agents, viscosity modifiers, lubricants, water resistant agents, water retention agents, coloring materials and the like.

Further, it is preferable that the coated surface coated with the clay coat layer is subjected to a super calendar treatment to smooth the surface. By performing the super calender 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 basis weight of the 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 .

<Release layer>
The release agent layer contained in the release material used in the present invention can be formed from a release agent composition containing a release component on a polyethylene layer.
Examples of the peelable component contained in the release agent composition which is the material for forming the release agent layer include alkyd resin, silicone resin, fluorine resin, 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 release 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.
^{The basis weight of the release agent layer is preferably 0.01 to 5 g / m 2} , more preferably 0.05 to 3 g / m 2, and even more preferably 0.1 to ¹ , from the viewpoint of peelability and curability of the coating film. It is 2 g / m ² .

<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, and ABS resins. 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 wax and polyethylene 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, from the viewpoint of forming a moisture-proof layer having improved film strength and heat resistance 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.
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 basis weight of the moisture-proof layer is preferably 1 to 10 g / ^{m 2,} more preferably 2 to 8 g / ^{m 2,} more preferably from 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 clay coat layer.
Examples of the material for forming the blocking prevention layer include styrene acrylic resin and the like.
^{The basis weight of the blocking prevention layer is preferably 0.01 to 5 g / m 2} , more preferably 0.05 to 3 g / m 2, and even more preferably 0.1 to ¹ , from the viewpoint of peelability and curability of the coating film. It is 2 g / m ² .

[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. 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 initiator, curing aid and the like.

The thickness of the pressure-sensitive adhesive layer is appropriately set according to the intended use, but is preferably 1 to 100 μm, more preferably 5 to 80 μm, and further 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 Boseki 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.
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 base material 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; fluorine resin and the like.

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 multi-layer 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 sandblasting method and a solvent treatment method.

The thickness of the surface base material is appropriately set according to 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 with a laser printer or the like, on the surface opposite to the pressure-sensitive adhesive layer of the surface base material. 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 clay coat layer on the first surface of the paper material.
-Step (2): A step of forming a moisture-proof layer on the clay coat layer.
-Step (3): A step of forming a polyethylene layer on a second surface opposite to the first surface of the paper material.
-Step (4): A step of forming a release agent layer on the polyethylene 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) does not matter, 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 order may be as in steps (1) to (4), or the order may be step (1), step (3), step (2), step (4), or step (1). The order may be 1), step (3), step (4), step (2), or step (3), step (1), step (2), step (4). It may be a step (3), a step (4), a step (1), or a step (2).

In each step, as a method for forming the clay coat layer, the moisture-proof layer, the release agent layer, the print receiving layer and the blocking prevention layer, the composition which is the forming material of each layer is applied to form a coating film, and the coating film is dried. By doing so, it can be formed.
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.

Known methods can be applied as a method for applying the clay coat layer, the moisture-proof layer, the release agent layer, the print receiving layer, and the blocking prevention layer. For example, a spin coating method, a spray coating method, a bar coating method, a knife coating method, etc. Examples include a roll coating method, a blade coating method, a die coating method, and a gravure coating method.
Examples of the method for forming the polyethylene layer include a method in which a polyethylene resin is melt-extruded onto a paper material and laminated.

[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 fixability of the toner on the surface base material side, which is the printing 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.

<Polyethylene resin>
Low density polyethylene (manufactured by Tosoh Corporation, product name "Petrosen 217-1", density: 923 kg / m ³ , melt flow rate: 4.5)

<Clay coat composition>
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. , Product name "Smart Tech SN-307R") 9 parts by mass, Oxidized starch (manufactured by Nippon Shokuhin Kogyo Co., Ltd., product name "Sanas 350") 9 parts by mass, 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 a blocking prevention 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 one surface (first surface) of the above paper material using a gravure coater to form a coating film, and dried at 150 ° C. for 20 seconds. Then, a clay coat layer was formed. Subsequently, the above polyethylene resin was extruded and laminated at a melting temperature of 325 ° C. on the opposite surface (second surface) of the obtained paper clay coat layer by a laminator equipped with a melt extrusion device, and tsubo on one side. clay coat layer in an amount 11g / ^{m 2,} was prepared paper having a polyethylene layer having a basis weight of 18 g / ^{m 2} on one side.
Next, the above release agent composition was applied onto the polyethylene layer of the obtained paper to form a coating film, and the coating film was dried at 150 ° C. for 20 seconds to have a basis weight of 0.5 g / m ² . A release agent layer was formed.
Further, the above composition for forming a moisture-proof layer was applied onto the clay coat layer to form a coating film, and the coating film was dried at 100 ° C. for 1 minute to form a moisture-proof layer having ^{a basis weight of 4 g / m 2.} .. Subsequently, the above composition for forming an blocking prevention 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 obtain a blocking prevention layer ^{having a basis weight of 1 g / m 2.} Was formed to prepare a release material (1) having a basis weight of 119 g / m ^2.

(2) Preparation of Adhesive Sheet An acrylic adhesive (manufactured by Lintec Corporation, product name "PAT1") is applied on the release agent layer of the produced release material (1) to form a coating film, and the coating film is formed. It was dried at 100 ° C. for 2 minutes to form a 20 μm thick pressure-sensitive adhesive layer. 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
A 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
As the release material (3), 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 (III) was obtained in the same manner as in Example 1.

Comparative Example 3
As the release material (4), a release material (manufactured by Lintec Corporation, product name "8E") having a release agent layer on a polyethylene layer of single-sided polyethylene laminated paper is used, and an adhesive sheet (adhesive sheet (manufactured by Lintec Corporation, product name "8E") is used in the same manner as in Example 1. IV) was obtained.

Comparative Example 4
The above composition for forming a moisture-proof layer is applied to the surface of the release material (4) opposite to the release agent layer to form a coating film, and the coating film is dried at 100 ° C. for 30 seconds to have a basis weight of 4 g / m. A moisture-proof layer of ^{2 was formed.} Subsequently, the above composition for forming an blocking prevention 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 obtain a blocking prevention layer ^{having a basis weight of 1 g / m 2.} Was formed to prepare a release material (5).
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), an adhesive sheet (manufactured by Lintec Corporation, product name "7K white") having a release agent layer on one surface of glassine paper is used in the same manner as in Example 1 (adhesive sheet (6)). VI) was obtained.

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 30 seconds to have a basis weight of 4 g / A moisture-proof layer of m ^{2 was formed.} Subsequently, the above composition for forming an blocking prevention 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 obtain a blocking prevention layer ^{having a basis weight 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.

Table 1 shows the composition, basis weight, etc. of the release material and the surface base material in the pressure-sensitive adhesive sheets (I) to (VII) produced as described above.
In addition, the following evaluations and measurements were performed on the adhesive sheets (I) to (VII). These results are shown in Table 2.

(1) Evaluation Method of Curling Suppressing 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 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 allowed to stand on a flat table, and the heights of the adhesive sheets from the tables at the four corners were measured, and the maximum value of the curl height was obtained. The maximum value of the curl height shown in Table 2 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 on the inside of the warped surface and the release material is on the outside of 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)
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 20 mm.
-4: 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.
-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 the curl height (absolute value of the numerical value in Table 1) is 70 mm or more.

(Curl evaluation 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 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 15 mm.
-3: 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.
-2: 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.
-1: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 50 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 3 mm.
-4: The maximum value of the curl height (absolute value of the numerical value in Table 1) is 3 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 the curl height (absolute value of the numerical value in Table 1) is 30 mm or more.

(2) Surface resistivity and volume resistivity Based on the four-terminal method specified in JIS K7194: 1994, each resistivity meter "Loresta GP MCP-T600" (product name, manufactured by Mitsubishi Chemical Corporation) is used. The surface resistivity and volume resistivity were measured from the release material side of the pressure-sensitive adhesive sheet.
In addition, the printability was evaluated based on the surface resistivity based on the following criteria.
(3) Evaluation of Printability The produced adhesive sheet was set to A4 size and color-printed on the surface substrate side using a laser printer (manufactured by Canon Inc., product name "LBP-9600").
◯: Toner was not scattered due to static electricity, the image was visually observed according to the data, and the toner (image) did not fall off even if the printed surface immediately after printing was rubbed with a finger.
X: A print state other than the above.

From Table 2, the adhesive sheet (I) produced in Example 1 was compared with the adhesive sheets (II) to (VII) 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 Release material 11 Paper material 12a Polyethylene layer 12b Clay coat layer 13 Release agent layer 14 Moisture-proof layer 20 Adhesive layer 30 Surface base material

Claims (5)

A release material having a clay coat layer on the first surface and a polyethylene layer on the second surface of the paper material, a release agent layer on the polyethylene layer, and a moisture-proof layer on the clay coat layer.
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. According to claim 1, the ratio [P / R] of the basis weight P (g / m ² ) of the paper material to the basis weight R (g / m ^{2) of the release material is 0.58 to 0.92.} The described adhesive sheet. The adhesive sheet according to claim 1 or 2, wherein the paper material has a basis weight of 30 to 300 g / m ² , and the polyethylene layer has a basis weight of 3 g / m ^{2 or more.} The adhesive sheet according to any one of claims 1 to 3, 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 adhesive sheet according to any one of claims 1 to 4, which is used for printing with a laser printer.

Images