JPH09235520A - Adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive sheet capable of dissolving an uneven feeling and a irregular luster on the surface thereof generated in the case of using a cast coated paper produced by using a rewet cast method and a gelation cast method. SOLUTION: This adhesive sheet obtained by laminating an adhesive layer and a releasing paper by using a cast coated paper obtained by a rewet cast method or a gelation cast method as a surface substrate, is the adhesive sheet having <=1.2×10<-2> standard deviation of values obtained by measuring light absorbencies of the original papers of the coated papers, performing Fourier transformation of the values expressed by (-)log(I/I0 ) of the data (I0 = amount of incident light, I = amount of transmitted light), expressing the results by frequencies and performing reverse Fourier transformation of only the frequencies corresponding to 4-10mm wave length.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet, and more particularly to a high-gloss pressure-sensitive adhesive sheet using cast coated paper as a surface substrate.

[0002]

2. Description of the Related Art Adhesive sheets are widely used as labels, stickers, stickers, patches, etc. for commercial use, office use, household use and the like. This pressure-sensitive adhesive sheet is generally constructed by laminating a surface base material, a pressure-sensitive adhesive, and release paper. As the surface base material, a paper base material such as high-quality paper, kraft paper, art paper, coated paper, cast coated paper, or a sheet material such as film, synthetic paper, or metal foil is used.
As the release paper, high-density paper such as glassine paper, clay coated paper, base paper for release paper such as polyethylene laminated paper coated with a release agent such as a silicone compound or a fluorine compound is used. As the pressure-sensitive adhesive, solvent-type pressure-sensitive adhesive, emulsion-type pressure-sensitive adhesive, hot melt-type pressure-sensitive adhesive, etc. are used.

On the other hand, cast coated paper has extremely high gloss as compared with other coated papers, and is therefore used as a surface base material for high-grade adhesive sheets. For cast coated paper, the base paper is coated with a casting coating solution containing pigments and adhesives as main components, and then pressure-bonded (pressure contact) to the surface of the heating drum having a mirror surface while the coating layer is in a wet state. Wet cast method of drying and gloss finish, rewet cast method of once drying the wet coating layer, plasticizing with re-wetting liquid and press contact with the heating drum surface, and further coating of wet state A gelling casting method is generally known in which a layer to be coated is in a gelled state and is brought into pressure contact with a surface of a heating drum to give a gloss finish.

Of these cast finishing methods, the rewet casting method and the gelling casting method are both dried or gelled before the cast coating layer is pressed against the mirror-finished drum surface, so that they are both surface-treated. Temperature is 90 ℃
Since it is possible to press finish against the above-mentioned relatively high temperature mirror surface drum for cast finishing, it is possible to increase the drying speed as compared with the wet casting method, and it is possible to obtain paper with excellent productivity and high gloss. . However, the adhesive sheet using the cast coated paper produced by the rewet casting method and the gelling casting method has high gloss, but the appearance of unevenness and uneven gloss on the surface of the pressure-sensitive adhesive sheet gives the appearance a high quality. It is difficult to obtain a pressure sensitive adhesive sheet.

[0005]

In view of the present situation, the present inventors have found that the pressure-sensitive adhesive sheet produced when a cast coated paper produced by the rewet casting method and the gelling casting method is used as the surface substrate. We investigated the causes of unevenness and uneven gloss on the surface from all angles, including the surface substrate, adhesive layer, and release paper. As a result, it was found that the wavelength unevenness (texture unevenness) occurring at intervals of 4 to 10 mm, which the base paper used for the cast coated paper has, and the unevenness and gloss unevenness on the surface of the pressure-sensitive adhesive sheet match. That is, it was found that the unevenness of the texture of the base paper of the cast coated paper causes the unevenness and gloss unevenness of the surface of the adhesive sheet.

In the production of cast coated paper, an air knife coater is generally used when providing a coating layer containing a pigment and an adhesive. Usually, such a coating layer requires a dry coating amount of about 25 to 30 g / m ² , and is required to be a layer having smoothness and bulkiness. With an air knife coater, this bulky and porous coating layer can be obtained, but it is easy to form a coating layer with unevenness that conforms to the unevenness of the base paper.Furthermore, the once dried coating layer is plasticized with a rewetting liquid. After that, or when the gelled coating layer is pressed against the heated mirror-finished drum surface to give a glossy finish, the smoothness of the glossy surface is improved, but the irregularities on the back surface become severe. Furthermore, since the rewetting liquid and the water content of the gelled coating layer pass through the base paper and evaporate from the back side, the fibers of the base paper are dried in a loose state, resulting in uneven formation of the base paper due to the back side of the base paper. Appears as severe irregularities.

When such a cast coated paper is used as a printing paper or the like, the unevenness on the back surface does not pose a problem, but when it is used as the surface base material of an adhesive sheet, the surface has a feeling of unevenness or gloss. It causes unevenness. Presumably, when finishing the pressure-sensitive adhesive sheet in a rolled-up state, a strong pressure is applied to the pressure-sensitive adhesive sheet inside the roll-up, so that unevenness on the back surface of the cast coated paper appears on the glossy surface. Usually 50-80g
/ M ² basis weight of cast coated paper is 10
By increasing the amount to about 0 g / m ^2, it is possible to suppress unevenness and gloss unevenness on the surface of the pressure-sensitive adhesive sheet, but when using the pressure-sensitive adhesive sheet, when sticking to curved surfaces etc. Since it becomes stronger, label floating such as peeling from the adherend adhered occurs, and the adhesive performance as the adhesive sheet deteriorates.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems. As a result, as a base paper for cast coated paper, the light transmittance of the base paper was measured (conditions:
Measuring spot 200μm square, measuring pitch 200μm,
Measurement area 204.8 mm x 204.8 mm, concentration range-
log (I / I ₀ ) = 1 to 4), -log of this data
A value represented by (I / I ₀ ), where I ₀ = incident light amount,
I = the amount of transmitted light) is Fourier transformed and displayed in frequency,
Inverse Fourier transform is performed only on the frequency having a wavelength of -10 mm, and a standard paper having a standard deviation value (standard deviation value of light transmittance unevenness occurring at intervals of 4 to 10 mm) of the obtained value is equal to or less than a specific value is used. They found that they could solve it.

That is, the present invention relates to a pressure-sensitive adhesive sheet comprising a cast coated paper obtained by the rewet casting method or gelation casting method as a surface base material, and a pressure-sensitive adhesive layer and release paper laminated on each other. The light transmittance of the base paper of the coated paper was measured, and the value represented by -log (I / I ₀ ) of this data (where, I ₀ = incident light amount, I = transmitted light amount)
Is represented by frequency after Fourier transform, and only the frequency having a wavelength of 4 to 10 mm is inverse Fourier transformed, and the standard deviation value of the obtained value is 1.2 × 10 ^-2 or less. It is a sheet.

Further, as a result of further research conducted by the inventor in order to obtain a pressure-sensitive adhesive sheet having no unevenness or uneven glossiness, the surface of the release paper also has unevenness due to formation unevenness of a wavelength of 4 to 10 mm. It was found that when the pressure-sensitive adhesive sheet was finished, the surface of the pressure-sensitive adhesive sheet appeared as unevenness and uneven gloss.

According to the present invention, the base paper of the release paper has a basis weight of 60 to 90 g / m ² , and the light transmittance of the base paper is measured and expressed by -log (I / I ₀ ) of this data. Value (here, I ₀ = incident light amount, I = transmitted light amount) is Fourier-transformed and displayed as a frequency, and only the frequency having a wavelength of 4 to 10 mm is inverse-Fourier-transformed, and the standard deviation value of the obtained value is obtained. Is 1.1 × 10 ^-2 or less, which is the above-mentioned pressure-sensitive adhesive sheet using a release paper.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present invention measures the light transmittance of the base paper of the cast coated paper used for the surface substrate. The measuring device measures the light transmittance of the base paper,
As long as the value of (I / I ₀ ) (where I ₀ = incident light amount, I = transmitted light amount) can be obtained, in the present invention, a drum scan densitometer model 2605 manufactured by Abe Design Co., Ltd. is used.
Measurement spot size: 200 μm × 200 μ
m, measurement pitch: 200 μm, concentration range: −log (I
/ I ₀ ) = 1 to 4, measurement area: 204.8 mm × 20
It was measured under the condition of 4.8 mm. This measurement data is input to an image analyzer (LUZEX-III manufactured by Nireco),
The value represented by log (I / I ₀ ) is Fourier-transformed and displayed as a frequency, and only the frequency having a wavelength of 4 to 10 mm is inverse-Fourier-transformed to obtain the standard deviation value of the obtained values.
A base paper having a standard deviation value of 1.2 × 10 ^-2 or less is used. Especially, the basis weight of the base paper is 50 to 80 g / m.
^When the base paper of No. ² is used, unevenness and uneven gloss are remarkably generated, so it is useful to use the base paper satisfying the standard deviation value. In the present invention, when such a base paper is used, a cast coated paper is obtained by a rewet casting method or a gelling casting method, and when the pressure sensitive adhesive sheet is used, a pressure sensitive adhesive sheet having no unevenness or uneven gloss can be obtained.

In the present invention, as a method for obtaining a base paper of cast coated paper used as a surface base material of a pressure-sensitive adhesive sheet, which satisfies the above-mentioned specific conditions, for example, selection of the type of paper machine or the structure of the head box, There are selections such as the dehydration conditions of the stock in the wire part, the stock concentration, the type and beating degree of the pulp, the type and the addition amount of the yield improver and the paper strength enhancer to be added to the paper amount, etc. The conditions of the base paper can be adjusted by appropriately combining the respective requirements.

For example, the shaking of the papermaking wire is strengthened so as to improve the dispersion of the pulp slurry (paper material), the paper material with the lowest possible concentration is used, and the pulp material is made of hardwood-based short fibers. Consideration should be given to the use of such an additive or the use of an internal additive that exhibits a cohesive action as much as possible. Of course, since the actual preparation has a balance with other paper qualities and paper qualities, adjustments are made by appropriately combining the above requirements.

The base paper thus obtained is coated with a coating liquid for cast coated paper used in the field of conventional cast coated paper, and is subjected to the usual rewet casting method or gelling casting method. A cast coated paper can be obtained by temporarily drying the coating layer, or after gelling, rewetting, press-contacting the surface of the metal drum having a heated mirror surface, and drying.

In the present invention, the base paper used as the release paper for the pressure-sensitive adhesive sheet is not particularly limited, and high-density paper such as glassine paper, which is usually used as the release paper base paper, clay coated paper, polyethylene laminated paper, etc. are used. . Above all, the light transmittance of the base paper used for the release paper is measured, and the value represented by -log (I / I ₀ ) of this data is Fourier-transformed and displayed as a frequency, and only the frequency with a wavelength of 4 to 10 mm is displayed. It is preferable to use a base paper having a standard deviation value of 1.1 × 10 ^-2 or less obtained by inverse Fourier transforming the obtained value, so that unevenness on the pressure-sensitive adhesive sheet surface can be further reduced when the pressure-sensitive adhesive sheet is finished. . 4-10 in base paper for release paper
The standard deviation value of the light transmittance unevenness at a wavelength of mm is 1.1 × 10.
^-2 or less can be obtained by appropriately adjusting the papermaking conditions as in the production of the base paper for cast coated paper.

There is no particular restriction on the release agent applied to the release paper base paper or the coating apparatus for providing the release agent layer, and there are thermosetting, ultraviolet ray curable and electron beam curable silicone compounds and fluorine. A normal bar coater for release agents such as compounds,
Various coaters such as a roll coater and a gravure coater, and a printing machine are appropriately used. The amount of release agent applied is such that the dry weight is about 0.2 to 3.0 g / m ² .

Regarding the method for constructing the pressure-sensitive adhesive sheet of the present invention, the pressure-sensitive adhesive is applied on the surface of the release agent layer of the release paper and dried to form the pressure-sensitive adhesive layer according to a usual production method, and the pressure-sensitive adhesive layer and the above The back side of the cast coated paper produced by the method is laminated and finished. As the pressure-sensitive adhesive, various pressure-sensitive adhesives such as a solvent-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, and a hot melt-type pressure-sensitive adhesive can be used. As a device for applying the pressure-sensitive adhesive, for example, a reverse roll coater, an air knife coater, a bar coater, a slot die coater, a reverse gravure coater, etc. are appropriately used. The adhesive is applied so that the dry weight is about 5 to 30 g / m ² .

The pressure-sensitive adhesive sheet of the present invention obtained as described above has a feeling of unevenness on the surface of the pressure-sensitive adhesive sheet, which is particularly visible.
It is also an excellent pressure-sensitive adhesive sheet in which uneven gloss is eliminated.

[0020]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
In addition, unless otherwise indicated, the part and% in an Example show solid content weight part and solid content weight%, respectively.

[0021]

【Example】

[Manufacture of Base Paper for Surface Base Material] (Production of Base Paper A for Surface Base Material) LBKP (450 ml C.I.
S. F. ) 70 parts and NBKP (450 ml C.S.
F. ) To 100 parts of a pulp slurry consisting of 30 parts, 10 parts of a 50% talc dispersion as a filler, 0.3 part of a reinforced rosin sizing agent (SPE / Arakawa Chemical Industry Co., Ltd.), and 1 part of aluminum sulfate are added, and for other papermaking. A stock was prepared by adding several chemicals. Next, paper is made from this stock material with a Fourdrinier paper machine, and 1.8 g / m ² (solid content) of oxidized starch (Ace A / Oji Corn Starch Co., Ltd.) is applied with a size press machine to obtain a weight of 64 g / m ^2. A base paper A for a surface substrate was obtained.

(Production of base paper B for surface base material) A method for producing base paper A for surface base material except that the papermaking concentration, the Jet / Wire ratio of the paper machine, the shaking of the wire, etc. were slightly changed as papermaking conditions. A base paper B for surface substrate was obtained in the same manner as described above.

(Production of base paper C for surface substrate) LBKP (5
00 ml C.I. S. F. ) 80 parts and NBKP (500 ml
C. S. F. ) 20 parts pulp slurry 100 parts as a filler 10 parts light calcium carbonate 10 parts reinforced rosin sizing agent (SPE / Arakawa Chemical Industry Co., Ltd.) 0.3 parts, aluminum sulfate 0.5 parts, cation modified starch (Amilofax 2200 / 0.5 parts (manufactured by Matsutani Chemical Industry Co., Ltd.) and several other paper-making chemicals were added to prepare a paper stock.
Next, paper is made from this stock material with a Fourdrinier paper machine, and 1.8 g / m ² (solid content) of oxidized starch (Ace A / Oji Corn Starch Co., Ltd.) is applied with a size press machine to obtain 64 g of tsubo.
A base paper C for surface substrate of / m ² was obtained.

(Production of base paper D for surface base material) A method for producing base paper C for surface base material except that the papermaking concentration, Jet / Wire ratio of the papermaking machine, wire shaking, etc. were slightly changed as papermaking conditions. In the same manner as above, a base paper D for surface base material was obtained.

[Production of Surface Substrate] (Production of Surface Substrate A) 70 parts of kaolin, 30 parts of calcium carbonate and 0.5 part of sodium polyacrylate were dispersed in water using a Choles disperser to obtain a solid content concentration. A 65% pigment slurry was prepared. 0.5 parts of tributyl phosphate as an antifoaming agent, 1.0 part of ammonium stearate as a releasing agent, 8 parts of 15% aqueous casein solution (solid content) dissolved with ammonia as an adhesive and styrene-butadiene were added to this slurry. 18 parts of the copolymer latex was added, and further 3 parts of zinc sulfate was added as a gelling agent to prepare a coating solution for rewet casting having a solid content concentration of 45%. Then, the above base paper A for a surface substrate was coated with the above-mentioned rewet casting coating liquid using an air knife coater so that the dry weight was 20 g / m ² , and then dried with an air floating dryer. Then, after rewetting the surface of the coated layer with a rewetting liquid (1.0% concentration) consisting of polyethylene emulsion, it is pressed against a cast drum having a surface temperature of 105 ° C. at a press pressure of 200 kg / cm and dried to form a cast coated paper. As a result, a surface base material A was obtained.

(Production of surface base material B) The same as the method for producing the surface base material A except that the base paper for surface base material B is used in place of the base paper for surface base material A in the method for producing the surface base material A. To obtain a surface base material B.

(Production of Surface Substrate C) 80 parts of kaolin, 10 parts of calcium carbonate, 10 parts of aluminum hydroxide, and 0.5 parts of sodium polyacrylate were dispersed in water using a Choles disperser to obtain a solid content concentration of 65. % Pigment slurry was prepared. 0.5 parts of tributyl phosphate as an antifoaming agent, 1.5 parts of funnel oil as a releasing agent, 14 parts of 15% casein aqueous solution (solid content) dissolved using ammonia as an adhesive and styrene-butadiene 10 parts of polymer latex (solid content) was added, and 0.1 part of aluminum sulfate was further added to prepare a gelling cast coating solution having a solid content concentration of 38%. Then, on the base paper C for the surface substrate, an air knife coater was used to obtain a dry weight of 20.
The coating solution for gelling cast was applied so as to be g / m ^2, and then pre-dried with an air floating dryer until the water content after application was 10%. Then, the coated layer was gelled with a 1% formic acid aqueous solution, and then pressed against a cast drum having a surface temperature of 105 ° C. at a pressing pressure of 150 kg / cm and dried to obtain a cast coated paper, which was used as a surface base material C.

(Production of Surface Substrate D) Same as the method for producing the Surface Substrate C, except that in the method for producing the Surface Substrate C, the base paper for the Front Substrate C was used instead of the base paper for the Substrate C. To obtain a surface base material D.

[Production of Release Paper Base Paper] (Production of Release Paper Base A) LBKP (470 ml C.I.
S. F. ) 70 parts and NBKP (470 ml C.S.
F. ) To 100 parts of a pulp slurry consisting of 30 parts, 10 parts of a 50% talc dispersion as a filler, 0.3 part of a reinforced rosin sizing agent (SPE / Arakawa Chemical Industry Co., Ltd.), 2 parts of aluminum sulphate, and for other papermaking are added. A stock was prepared by adding several chemicals. Next, a paper was made from this stock material by a Fourdrinier paper machine to obtain a base paper having a basis weight of 85 g / m ² . Then, a low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd.) melted on one surface of the base paper was laminated by a laboratory melt extruder to produce a base paper A for release paper.

(Production of base paper B for release paper) Same as the method for producing base paper A for release paper, except that the papermaking concentration, the Jet / Wire ratio of the papermaking machine, the shaking of the wire, etc. were slightly changed as papermaking conditions. A base paper B for release paper was obtained.

(Production of Base Paper C for Release Paper) LBKP (19
0 ml C.I. S. F. ) 30 parts and NBKP (190 ml
C. S. F. ) Reinforcement rosin sizing agent (SPE / Arakawa Chemical Industry Co., Ltd.) in 100 parts of 70 parts pulp slurry
0.4 parts and 2 parts of aluminum sulfate were added, and several other paper-making chemicals were added to prepare a paper stock. Next, paper is made from this stock material with a Fourdrinier paper machine, and polyvinyl alcohol (PVA117 / made by Kuraray) is applied with a size press device so that both sides have 3.0 g / m ² (solid content) and dried,
Further processed by super calender 80 g / m 2
Glassine paper No. ² was obtained and used as release paper base paper C.

(Manufacture of base paper D for release paper) Same as the method for manufacturing base paper C for release paper, except that the papermaking concentration, the Jet / Wire ratio of the papermaking machine, the shaking of the wire, etc., were slightly changed. Then, a base paper D for release paper was obtained.

[Production of Release Paper] (Production of Release Paper A) A solvent-based silicone release agent (SD
-7220 / Toray Dow Corning Silicone) 100
Part, platinum catalyst (SRX-212 / Toray Dow Corning Silicone) 0.6 parts, diluted with toluene, coated with a bar coater to a dry weight of 1.0 g / m ^2, and dried and cured. Release paper A was obtained.

(Production of Release Paper B) In the production method of release paper A, release paper B is produced in the same manner as in the production method of release paper A except that base paper B for release paper is used instead of base paper A for release paper.
I got

(Production of Release Paper C) 100 parts of a solvent type silicone release agent (SD-7220 / made by Toray Dow Corning Silicone), platinum catalyst (SRX-212 / Toray Dow Corning Silicone) are provided on one surface of the above-mentioned base paper C for release paper. Made)
A mixture of 0.6 parts was diluted with toluene, coated with a bar coater to a dry weight of 1.5 g / m ^2, and dried and cured to obtain release paper C.

(Production of Release Paper D) Release paper D is produced in the same manner as release paper C except that release paper base paper B is used instead of release paper base paper C.
I got

"Measurement of Standard Deviation Value of Light Transmittance Unevenness Occurring at 4-10 mm Intervals" Standard deviation value of light transmittance unevenness at wavelengths of 4 to 10 mm for each surface base paper and release paper base paper. Was measured under the following conditions. Table 1 shows the results.

(Measurement of Light Transmittance) Measuring Equipment: Drum Scan Densitometer Model 2
Light source: JC24V 150W halogen lamp Measurement spot size: 200 μm × 200 μm Measurement pitch: 200 μm Measurement area: 204.8 × 204.8 mm Measurement concentration range: −log (I / I ₀ ) = 1 to 4 ( I ₀ =
Incident light amount, I = transmitted light amount) Drum rotation speed: 10 rpm

(Image analysis) Image analysis device: LUZEX-III / manufactured by Nireco Co., Ltd. After inputting measured values, Fourier transform was performed and the frequency was displayed.
Only the frequency part having a wavelength of -10 mm was extracted. Further, the frequency portion was subjected to inverse Fourier transform and expressed by light transmittance, and then the standard deviation value was calculated.

[0040]

[Table 1]

Example 1 (Production of pressure-sensitive adhesive sheet) The release agent B was coated on the release agent-coated surface with a commercially available product.
Acrylic emulsion adhesive (trade name: Nikazol L
-145 / Nippon Carbide Industry Co., Ltd.) dry weight
Is 25 g / m ^TwoWith a reverse roll coater
After coating and drying, stick it to the back side of the surface base material B
I got it.

Example 2 An adhesive sheet was produced in the same manner as in Example 1 except that the release paper C was used instead of the release paper B in the method for producing the pressure-sensitive adhesive sheet of Example 1.

Example 3 In the method for producing a pressure-sensitive adhesive sheet of Example 1, the surface base material B
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the surface substrate D was used instead of.

Example 4 A pressure-sensitive adhesive sheet was manufactured in the same manner as in Example 1 except that the release paper A was used in place of the release paper B in the method for producing the pressure-sensitive adhesive sheet of Example 1.

Example 5 A pressure-sensitive adhesive sheet was manufactured in the same manner as in Example 1 except that the release paper D was used in place of the release paper B in the method for producing the pressure-sensitive adhesive sheet of Example 1.

Comparative Example 1 In the method for producing the pressure-sensitive adhesive sheet of Example 1, the surface base material B
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the surface base material A was used instead of.

Comparative Example 2 In the method for producing a pressure-sensitive adhesive sheet of Example 1, the surface base material B
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the surface base material A was used instead of and the release paper C was used instead of the release paper B.

Comparative Example 3 In the method for producing a pressure-sensitive adhesive sheet of Example 1, the surface base material B
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the surface base material C was used instead of.

Comparative Example 4 In the method for producing the pressure-sensitive adhesive sheet of Example 1, the surface base material B
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the surface base material A was used in place of and the release paper A was used in place of the release paper B.

Comparative Example 5 In the method for producing the pressure-sensitive adhesive sheet of Example 1, the surface base material B
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the surface base material C was used instead of and the release paper D was used instead of the release paper B.

"Evaluation" The unevenness and gloss unevenness of the surface of the obtained pressure-sensitive adhesive sheet were measured by the following methods, and the results are shown in Table 2.
Shown in

(Unevenness) The unevenness of the pressure-sensitive adhesive sheet surface was visually evaluated according to the following criteria. ⊚: No unevenness ○: Slightly unevenness, but practically no problem △: Unevenness ×: Many unevenness

(Glossiness unevenness) The glossiness unevenness on the surface of the pressure-sensitive adhesive sheet was visually evaluated according to the following criteria. ⊚: No gloss unevenness ○: Slight gloss unevenness but practically no problem Δ: Gloss unevenness ×: Many gloss unevenness

[0054]

[Table 2]

From Table 2, -log (I
/ I ₀ ) (I ₀ = incident light amount, I = transmitted light amount), the standard deviation value of unevenness of light transmittance at a wavelength of 4 to 10 mm is 1.2 × 10 ⁻² or less. Using base paper,
It can be seen that the pressure-sensitive adhesive sheet produced by producing cast-coated paper and using it as the surface base material is an excellent pressure-sensitive adhesive sheet having no surface irregularities and no uneven gloss. As can be seen from Example 4 and Example 5, 4 to 1 of the base paper for the surface base material
Standard deviation value of light transmittance unevenness of 0 mm wavelength is 1.2 x 1
Use a base paper that is a surface base material that uses a base paper of 0 ^-2 or less and that has a standard deviation value of 1.1 x 10 ^-2 or less of uneven light transmittance of the base paper for release paper at a wavelength of 4 to 10 mm. The pressure-sensitive adhesive sheet, which is a release paper, is an extremely excellent pressure-sensitive adhesive sheet without any unevenness on the surface or uneven gloss. Comparative Examples 4 and 5 are pressure-sensitive adhesive sheets using a base paper for release paper having a standard deviation value of the light transmittance unevenness of 4 to 10 mm wavelength of 1.1 × 10 ⁻² or less. 4-10 of base paper for lumber
The standard deviation value of the light transmittance unevenness at the wavelength of mm is 1.2 × 10.
^{Since the} base paper with a value larger than ^-2 is used, the unevenness of the adhesive sheet surface and uneven gloss are not sufficiently resolved.

[0056]

As described above, the pressure-sensitive adhesive sheet produced by using the base paper for surface base material and the base paper for release paper obtained in the present invention has a particularly uneven appearance and uneven gloss on the surface of the pressure-sensitive adhesive sheet. It was an excellent adhesive sheet that was eliminated.

Claims (3)

[Claims] A cast coated paper obtained by a rewet casting method or a gelling casting method is used as a surface substrate.
In a pressure-sensitive adhesive sheet formed by laminating a pressure-sensitive adhesive layer and a release paper, the light transmittance of the base paper of the cast coated paper was measured, and the value represented by -log (I / I ₀ ) of this data (here, , I ₀ = incident light amount, I = transmitted light amount) is Fourier-transformed and displayed as a frequency, and only the frequency having a wavelength of 4 to 10 mm is inverse Fourier-transformed, and the standard deviation value of the obtained values is 1.
A pressure-sensitive adhesive sheet having a size of 2 × 10 ^-2 or less. 2. The basis weight of the cast coated base paper is 50 to 70.
The pressure-sensitive adhesive sheet according to claim 1, which is g / m ² . 3. The release paper base paper has a base paper basis weight of 60 to 90 g.
/ M ² and the light transmittance of the base paper was measured, and the value represented by −log (I / I ₀ ) of this data (here, I ₀
= Incident light amount, I = transmitted light amount) is Fourier-transformed and displayed as a frequency, and only the frequency having a wavelength of 4 to 10 mm is inverse Fourier-transformed, and the standard deviation value of the obtained values is 1.1 × 10.
The pressure-sensitive adhesive sheet according to claim 1 or ² , wherein a release paper having a thickness of ^-2 or less is used.