JP4960811B2 - Release paper for pressure-sensitive adhesive sheets, production method thereof, and pressure-sensitive adhesive sheet using the release paper for pressure-sensitive adhesive sheets - Google Patents

Description

The present invention relates to a release paper suitable for a pressure-sensitive adhesive sheet using a plastic film or the like as a surface substrate, and in particular, a release sheet for a pressure-sensitive adhesive sheet that can suppress gloss unevenness of the surface substrate generated in a product roll core , The present invention relates to a production method and an adhesive sheet using the same.

  Conventionally, an easily peelable release material is bonded to the adhesive surface of an adhesive label or an adhesive sheet in order to protect the adhesive surface before use. As such a release material, the thing which apply | coated the easily peelable silicone resin (silicone mold release agent) to the surface, such as paper and a film which is a base material, is used. In this case, from the viewpoint of workability and the viewpoint of reducing the manufacturing cost of the release material, paper is usually used as the substrate, regardless of whether it is used for special applications.

  Moreover, paper, a plastic film, etc. are used as the surface base material in the pressure-sensitive adhesive sheet, and acrylic and rubber-based materials are mainly used as the pressure-sensitive adhesive. As a release material, one side of a base paper such as fine paper is melt-extruded laminate layer of a polyolefin-based thermoplastic resin, or the surface-treated surface of a base paper treated with a pigment coat layer such as clay, a silicone resin, A release material coated with a release agent such as an alkyd resin or a long-chain alkyl resin is used.

As the surface base material in the pressure-sensitive adhesive sheet, a high-intensity plastic film such as a reflective material is used, and when laminated and wound as the pressure-sensitive adhesive sheet, gloss unevenness may occur on the surface base material in the vicinity of the core. . This is a phenomenon that occurs when a plastic film used as a surface base material is laminated as an adhesive sheet and wound, and the surface base material is affected by the back surface of the release material due to the winding pressure in the vicinity of the core.
Such gloss unevenness causes a reflection defect in a reflective material characterized by high brightness.

On the other hand, a release paper in which a release agent is applied to one side of a base paper and a resin layer is provided on the other side has been proposed (Patent Documents 1 and 2). The main purpose of this resin layer is to prevent curling when the pressure-sensitive adhesive sheets are laminated, and there is no literature that refers to the gloss unevenness of the surface substrate that occurs when the pressure-sensitive adhesive sheets are laminated and wound. Absent. However, recently, the demand for product quality has become more severe, and the portion where the uneven gloss as described above has no commercial value has been a main cause of the deterioration of the product yield.
Japanese Patent Laid-Open No. 08-183134 Japanese Patent Laid-Open No. 11-131395

Therefore, the present inventors have intensively studied to prevent the occurrence of uneven gloss of the surface base material that occurs in the vicinity of the core when the pressure-sensitive adhesive sheet is laminated and wound up. It has been found that good results can be obtained by making the surface roughness of the outermost layer on the opposite side of the release paper layer in contact with the release paper layer a certain value or more, and the release paper of the present invention has been reached.
Accordingly, an object of the present invention is to prevent uneven gloss on the surface base material in the vicinity of the wound core of the wound pressure-sensitive adhesive sheet when the pressure-sensitive adhesive sheet is wound up during the production of the pressure-sensitive adhesive sheet. It is to provide a release paper that can be used.

That is, the present invention provides a release paper having a release agent layer on one side of a base paper and a resin layer on the other side, the surface of the outermost layer on the resin layer side based on JIS B 0601-1994. roughness, with at 1μm or more in arithmetic average roughness (Ra), the pressure-sensitive adhesive sheet for release paper, wherein a ten point average roughness (Rz) is 8μm or more, the release of the pressure-sensitive adhesive sheet for release paper On the surface of the mold layer, a pressure-sensitive adhesive sheet formed by bonding a surface base material made of a plastic film through the pressure-sensitive adhesive layer, and a release agent layer on one surface of the base paper, A method for producing a pressure-sensitive adhesive sheet by providing a resin layer on the other surface, wherein a method is used to transfer the unevenness using a cooling roll provided with unevenness on the outermost layer on the resin layer side, the resin layer A pigment having an average particle size of 0.1 to 20 μm was blended on The surface roughness based on JIS B 0601-1994 is 1 μm or more in terms of arithmetic average roughness (Ra), and the ten-point average roughness (Rz) by any method of providing a writing layer containing fat. In this method, the outermost layer on the resin layer side is roughened so that the thickness becomes 8 μm or more .

  The release agent layer is preferably provided on at least one sealing layer provided on the surface of the base paper, and the sealing layer is provided by a polyolefin resin, polyvinyl alcohol, or clay coat. More preferably.

The resin layer is preferably a thermoplastic resin, and the adhesive sheet of the present invention may further include a writing layer on the surface of the resin layer.
The resin layer or the resin layer and the writing layer preferably have a moisture permeability of 100 g / m ² · 24 hours or less based on JIS Z 0208.

  The release paper of the present invention can prevent gloss unevenness in the vicinity of the core when the pressure-sensitive adhesive sheet is laminated and wound, thereby reducing the number of defective products and improving the product yield. To do. Further, curling of the pressure-sensitive adhesive sheet is also suppressed, so that product storage is improved.

One example of the pressure-sensitive adhesive sheet of the present invention is shown in FIG. In FIG. 1, a plastic film 3 and an adhesive layer 4 constitute an adhesive film 1, and a release agent layer 5, a sealing layer 6, a base paper 7, a resin layer 8, and a writing provided as appropriate. Layer 9 constitutes release paper 2 of the present invention.
The base paper used in the present invention can be appropriately selected from known papers such as fine paper, kraft paper, glassine paper, and nonwoven fabric. The basis weight of the base paper is preferably 30 to 300 g / m ² .

  The release agent used for the release agent layer of the release paper of the present invention is appropriately selected from known release agents such as silicone resins, fluororesins, alkyd resins, and long-chain alkyl resins. it can. The thickness of the release agent layer is preferably 0.01 to 10 μm, and more preferably 0.1 to 5 μm.

  In the release paper of the present invention, it is preferable to provide a sealing layer before applying the aforementioned release agent. As such a sealing layer, known ones can be used, for example, formed by using polyolefin resins such as low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polyvinyl alcohol, clay, etc. Can be made. The sealing layer may be formed by laminating not only one layer but also two or more layers. The thickness of the entire sealing layer is preferably 0.5 to 100 μm, and more preferably 1 to 50 μm.

  As a resin used for the resin layer of the release paper of the present invention, one or more thermoplastic resins such as a polyethylene resin, a polyvinylidene chloride resin, a polystyrene resin, and an acrylic resin are appropriately selected and used. be able to. These resins may be formed by laminating not only one layer but also two or more layers. In the present invention, it is particularly preferable to use a polyethylene resin that is inexpensive and excellent in laminating properties. Moreover, it is preferable that the thickness of a resin layer is 1-100 micrometers, and it is more preferable that it is 1-50 micrometers.

The resin layer provided on the release paper of the present invention preferably has a moisture permeability of 100 g / m ² · 24 hours or less, more preferably 50 g / m ² · 24 hours or less based on JIS Z 0208.
That is, the plastic film used as the surface substrate has low moisture permeability, whereas the base paper has high moisture permeability. Therefore, in a high humidity environment, the adhesive sheet curls due to the difference in elongation between the plastic film and the base paper. Occurrence becomes remarkable. For this reason, depending on the region and environment in which the product is used, the burden associated with product management before use may be a problem, or the product value may be significantly reduced. In the present invention, in order to make the moisture permeability of the entire surface on the opposite side of the release agent layer of the base paper 100 g / m ² · 24 hours or less, by completely covering with a resin layer such as polyethylene resin, Curling can be prevented.

In the release paper of the present invention, the surface roughness of the outermost layer on the resin layer side based on JIS B 0601-1994 must have an arithmetic average roughness (Ra) of 1 μm or more, and 2 μm or more. Is preferred. Further, the ten-point average roughness (Rz) needs to be 8 μm or more, and preferably 10 μm or more. By making such a roughness, it is possible to prevent uneven gloss from occurring on the surface of the plastic film in the vicinity of the core when the pressure-sensitive adhesive sheet as the final product is wound on a roll. When the surface of the outermost layer on the resin layer side is smooth and Ra is less than 1 μm or Rz is less than 8 μm, uneven gloss tends to occur in the vicinity of the core of the pressure-sensitive adhesive sheet.
In the present invention, the “outermost layer on the resin layer side” means a resin layer when only the resin layer is provided on the opposite surface of the release agent layer of the release paper, and will be described later. When a writing layer is further provided on the resin layer, it is a writing layer.

  The upper limit of the surface roughness of the outermost layer is not particularly limited, but Ra is preferably 50 μm or less, and more preferably 20 μm or less. Rz is preferably 100 μm or less, and more preferably 50 μm or less. When Ra exceeds 50 μm and Rz exceeds 100 μm, the outermost layer on the resin layer side becomes unnecessarily thick and the production rate is remarkably lowered, which is not preferable.

  The greatest feature of the release paper of the present invention is that the outermost layer on the resin layer side has the surface roughness as described above. The roughening of the outermost layer can be appropriately performed by a known method. However, unevenness is provided on the surface of the cooling roll used when the resin layer is melt-extruded laminated on the base paper, and the unevenness is provided on the outermost layer on the resin layer side. A method of transferring to the surface of the outer layer can be mentioned as a preferred method.

  The release paper of the present invention may be provided with a writing layer on the resin layer as necessary. As a writing layer, polyolefins such as polyethylene and polypropylene, organic pigments such as polystyrene and acrylic resins, or inorganic pigments such as calcium carbonate, barium sulfate, and talc blended with resins such as polyacrylamide, polyurethane, and polyolefin, etc. Well-known ones can be used.

  The average particle size of the pigment used for the writing layer is preferably 0.1 to 20 μm, and more preferably 1 to 10 μm. When the average particle size is less than 0.1 μm, the pigment is easily aggregated, so that it is difficult to disperse in the writing layer. When the average particle size is more than 20 μm, the retention of the pigment particles in the dried writing layer deteriorates and drops off. It becomes easy.

  When a writing layer is provided, the roughness of the writing layer surface needs to be the values of Ra and Rz described above. In this case, as in the case of the resin layer, the unevenness of the cooling roll used when the resin layer and the writing layer are melt-extruded laminated on the base paper may be transferred to the outermost layer, but the pigment in the writing layer Roughening with particles is preferred. In this case, the average particle size of the pigment used is preferably 3 μm or more, and more preferably 6 μm or more. If it is less than 3 μm, sufficient unevenness may not be obtained. The pigments used in the present invention are rarely present in the state of primary particles (particles alone), and are present in a state where several particles are aggregated. Therefore, sufficient unevenness is obtained even if the average particle size is 3 μm. Obtainable.

  The thickness of the writing layer is preferably 0.5 to 20 μm, and more preferably 1 to 10 μm. If it is less than 0.5 μm, the writing property is inferior, and if it exceeds 20 μm, it is not preferable economically, and it takes a considerable time to dry after coating the writing layer, and the production efficiency is lowered.

The pressure-sensitive adhesive sheet of the present invention is obtained by applying a pressure-sensitive adhesive to the surface of the release agent layer of the release paper of the present invention described above by a known method and drying to form a pressure-sensitive adhesive layer. It can be easily manufactured by laminating and winding a plastic film as a surface base material. Examples of the plastic film include high-intensity plastic films such as reflectors, and plastic films used for ordinary adhesive films such as polyester, polypropylene, and polyvinyl chloride. It is not limited.
The thickness of the plastic film used is preferably 5 to 300 μm, and more preferably 10 to 200 μm.

The pressure-sensitive adhesive is not limited to acrylic, rubber-based, silicone-based, epoxy-based, polyester-based, urethane-based, polyolefin-based, and the like, and known materials can be used widely as appropriate. The thickness of the pressure-sensitive adhesive layer is preferably 5 to 200 μm, and more preferably 10 to 100 μm. If it is less than 5 μm, the adhesive strength may be insufficient or it may be difficult to make the thickness of the pressure-sensitive adhesive layer uniform, and if it exceeds 200 μm, it is not economically preferable. A considerable amount of time is required for drying, which is not preferable because the production efficiency is lowered or the pressure-sensitive adhesive easily protrudes from the end when the pressure-sensitive adhesive sheet is formed.
EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited by these Examples.

Polyethylene resin on the opposite side of the release agent layer of single-sided polyethylene laminate release paper (E1P-L- (P), product name of Lintec Co., Ltd.) consisting of a base paper, a sealing layer and a release agent layer A release paper of the present invention was manufactured by providing a resin layer (Petrocene 217, trade name of Tosoh Corporation).
The surface roughness of the release paper was measured with a stylus type surface roughness meter (Surf Test SV3000, trade name, manufactured by Mitutoyo Corporation).

The resin layer is formed by cooling the polyethylene resin on the opposite surface of the release agent layer at a T-die temperature of 320 ° C. with a surface roughness of Ra = 7.80 μm and Rz = 37.10 μm. Pressing against a roll to transfer the irregularities to the resin, a resin layer having an average thickness of 35 μm per 1 m ² was provided. The surface roughness of the outermost layer on the resin layer side of the release paper thus obtained was Ra = 4.90 μm and Rz = 22.72 μm.
Next, an adhesive film (license grade ELC, trade name of Nippon Carbide Industries Co., Ltd.) was bonded to the surface of the release agent layer of the release paper to obtain an adhesive sheet.

A resin layer was provided in the same manner as in Example 1 except that a cooling roll having a surface roughness of Ra = 6.00 μm and Rz = 32.80 μm was used. The surface roughness of the resin layer was Ra = 4.94 μm and Rz = 24.01 μm.
Furthermore, the adhesive film was bonded like Example 1 and the adhesive sheet was obtained.

Except that a cooling roll with a surface roughness of Ra = 3.51 μm and Rz = 18.01 μm was used, and the average thickness of the resin layer per 1 m ² was 25 μm, the same as in Example 1. A resin layer was provided. The surface roughness of the resin layer was Ra = 2.08 μm and Rz = 10.17 μm.
Furthermore, the adhesive film was bonded like Example 1 and the adhesive sheet was obtained.

The surface roughness was the same as in Example 1 except that a cooling roll with Ra = 2.93 μm and Rz = 14.42 μm was used, and the average thickness of the resin layer per 1 m ² was 25 μm. A resin layer was provided. The surface roughness of the resin layer was Ra = 2.35 μm and Rz = 12.55 μm.
Furthermore, the adhesive film was bonded like Example 1 and the adhesive sheet was obtained.

[Comparative Example 1]
An adhesive film was bonded in the same manner as in Example 1 except that the resin layer was not provided on the surface opposite to the release agent layer to obtain an adhesive sheet.
The surface roughness of the opposite surface of the release agent layer of the base paper was Ra = 1.98 μm and Rz = 12.16 μm.

[Comparative Example 2]
Except for using a cooling roll with a surface roughness of Ra = 1.13 μm and Rz = 7.42 μm, and that the average thickness of the resin layer per 1 m ² was 25 μm, the same as in Example 1. A resin layer was provided. The surface roughness of the resin layer was Ra = 0.80 μm and Rz = 4.87 μm.
Furthermore, the adhesive film was bonded like Example 1 and the adhesive sheet was obtained.

  Calcium carbonate (NS #) having a polyacrylamide resin (Cosmotone Z, trade name of Toyo Ink Manufacturing Co., Ltd.) 70 parts by mass and a particle size (hereinafter simply referred to as “particle size”) determined from the specific surface area of 1.7 μm. 400, 70 parts by mass of a product name manufactured by Nitto Flour Industry Co., Ltd., and 30 parts by mass of calcium carbonate having a particle size of 8 μm (NS # 30, a product name manufactured by Nitto Flour Industry Co., Ltd.) (both solid Min) was diluted with a mixed solvent having a mass ratio of toluene / 2-propanol = 8/2 so that the solid content was 10% by mass to prepare a coating liquid (A).

On the resin layer provided in Comparative Example 2, the coating liquid (A) was applied using a Mayer bar so that the coating amount after drying was 2 g / m ^2, and then at a temperature of 90 ° C. And dried for 30 seconds to provide a writing layer.
The surface roughness of the writing layer was Ra = 2.17 μm and Rz = 12.57 μm.
Furthermore, the adhesive film was bonded like Example 1 and the adhesive sheet was obtained.

  70 parts by mass of polyacrylamide resin (Cosmotone Z, trade name manufactured by Toyo Ink Mfg. Co., Ltd.) and calcium carbonate having a particle size of 0.8 μm (NS # 3000, trade name manufactured by Nitto Flour & Chemical Co., Ltd.) 100 parts by mass (both solid content) was diluted with a mixed solvent having a mass ratio of toluene / 2-propanol = 8/2 so that the solid content would be 10% by mass to prepare a coating liquid (B). did.

On the opposite surface of the release agent layer of the single-sided polyethylene laminate release paper (E1P-L- (P), product name manufactured by Lintec Corporation), the polyethylene resin used in Example 1 was applied at a T-die temperature of 320 ° C. When performing melt extrusion lamination, the surface roughness was pressed against a cooling roll with Ra = 6.00 μm and Rz = 32.80 μm, the unevenness was transferred to the resin, and a resin layer having an average thickness of 35 μm per 1 m ² was provided. .

Furthermore, after applying the coating liquid (B) on the resin layer using a Mayer bar so that the coating amount after drying is 1 g / m ² , the coating liquid is dried at a temperature of 90 ° C. for 30 seconds. Dried and provided a writing layer.
The surface roughness of the writing layer was Ra = 6.41 μm and Rz = 29.00 μm.
Next, an adhesive sheet was obtained in the same manner as in Example 1.

[Comparative Example 3]
Polyvinylidene chloride (PVDC) resin (Saran latex L-536B, Asahi Kasei Chemicals) Co., Ltd. product name) was applied using a Meyer bar so that the coating amount after drying was 15 g / m ^2, and dried at 100 ° C. for 60 seconds to provide a resin layer.
The surface roughness of the resin layer was Ra = 1.19 μm and Rz = 5.17 μm.
Further, an adhesive sheet was obtained in the same manner as in Example 1.

About the release paper and adhesive sheet obtained by each Example and the comparative example, the characteristic was evaluated with the following method. The results are shown in Table 1.
1. Gloss unevenness prevention property Two 5 × 5 cm pressure-sensitive adhesive sheet samples are stacked so that one pressure-sensitive adhesive film surface and the other pressure-sensitive adhesive film are in contact with each other, and the pressure is 320 g / cm ² and the temperature is 50 ° C. After standing for a period of time, the surface glossiness of the adhesive film was measured, and gloss unevenness on the surface of the sheet was visually evaluated. The glossiness was measured at an incident angle of 75 degrees according to JIS P-8142-1993.
The case where no gloss unevenness was confirmed was marked with ◯, and the case where gloss unevenness was confirmed was marked with x.
2. Curling prevention property A 30 × 30 cm pressure-sensitive adhesive sheet sample was allowed to stand in an atmosphere of 23 ° C. and 80% humidity for 1 hour, and the height of turning up of the four corners of the sample was measured.
All four corners with a turn-up height of less than 30 mm were marked with ◯, and at least one of the four corners with a turn-up height of 30 mm or more was marked with x.
3. Moisture permeability The moisture permeability of the release paper of each example and comparative example, such as a resin layer, cannot be directly compared because of the influence of the release agent layer and the sealing layer. Therefore, the moisture permeability of these resin layers and the like was measured by the following method.
The same resin layer or resin layer as that used in each example or comparative example on commercially available high-quality paper (EK-A, trade name of Nippon Paper Industries Co., Ltd., US basis weight 116.3 g / m ² ), and Samples for measuring moisture permeability, in which a writing layer was laminated, were prepared, and moisture permeability of these samples was measured based on JIS Z 0208.

  As is clear from Table 1, the release paper of the present invention is excellent in preventing uneven glossiness of the surface substrate when it is made into an adhesive sheet. Therefore, even if the adhesive sheets are stacked and stored, uneven glossiness is present on the surface of the plastic film. It was confirmed that high glossiness was maintained without being generated. Moreover, since it has a resin layer, it was confirmed that it also has an anti-curl property.

  The pressure-sensitive adhesive sheet of the present invention is excellent in gloss unevenness prevention and curl prevention, and since no gloss unevenness occurs in the plastic film even in the vicinity of the core, it is excellent in production suitability and can improve the product yield.

It is a figure which shows an example of the adhesive sheet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adhesive film 2 Release paper 3 Plastic film 4 Adhesive layer 5 Release agent layer 6 Sealing layer 7 Base paper 8 Resin layer 9 Writing layer

Claims (13)

In a release paper having a release agent layer on one side of the base paper and a resin layer on the other side, the surface roughness of the outermost layer on the resin layer side based on JIS B 0601-1994 is an arithmetic average A release paper for pressure-sensitive adhesive sheets, having a roughness (Ra) of 1 μm or more and a 10-point average roughness (Rz) of 8 μm or more. The surface roughness based on JIS B 0601-1994 of the outermost layer on the resin layer side is 2 μm or more in arithmetic average roughness (Ra) and 10 μm or more in 10-point average roughness (Rz). Item 2. The release sheet for pressure-sensitive adhesive sheets according to item 1. The surface roughness of the outermost layer on the resin layer side based on JIS B 0601-1994 is 2 to 20 μm in arithmetic average roughness (Ra) and 10 to 50 μm in ten-point average roughness (Rz). The release sheet for pressure-sensitive adhesive sheets according to claim 2. The resin layer is made of a thermoplastic resin, and the release agent layer is provided on a sealing layer made of at least one polyolefin resin, polyvinyl alcohol or clay coat provided on the surface of the base paper. The release paper for pressure-sensitive adhesive sheets according to claim 1 , wherein the resin layer and the sealing layer each have a thickness of 1 to 50 μm . The surface of the said resin layer contains the resin selected from polyacrylamide, a polyurethane, and polyolefin, and also provides the writing layer whose thickness is 0.5-20 micrometers further in any one of Claims 1-4. Release paper for adhesive sheets. The writing layer contains at least one pigment selected from polyethylene, polypropylene, polystyrene, acrylic resin, calcium carbonate, barium sulfate, and talc, and the average particle size of the pigment is 0.1 to 20 μm. The release paper for pressure-sensitive adhesive sheets according to claim 5 .   The surface of the outermost layer on the resin layer side is roughened by transferring the unevenness using a cooling roll provided with unevenness, or by providing a writing layer made of a resin mixed with a pigment. The release sheet for pressure-sensitive adhesive sheets according to any one of claims 1 to 6. The moisture permeability based on JIS Z 0208 of the resin layer or the resin layer and the writing layer is 100 g / m. ² -The release paper for adhesive sheets as described in any one of Claims 1-7 which is 24 hours or less. The moisture permeability based on JIS Z 0208 of the resin layer or the resin layer and the writing layer is 50 g / m. ² -The release sheet for adhesive sheets of Claim 8 which is 24 hours or less. A surface substrate made of a plastic film is bonded to the surface of the release agent layer of the release sheet for the pressure-sensitive adhesive sheet according to any one of claims 1 to 9 through the pressure-sensitive adhesive layer. Adhesive sheet . The pressure-sensitive adhesive sheet according to claim 10, wherein the plastic film is a plastic film selected from a high-intensity plastic film, a polyester film, a polypropylene film, and a polyvinyl chloride film. A method for producing a pressure-sensitive adhesive sheet by providing a release agent layer on one side of a base paper and providing a resin layer on the other side, wherein the outermost layer on the resin layer side is provided with irregularities. JIS B by any one of the following methods: a method of transferring the projections and depressions, and a method of providing a writing layer containing a resin in which a pigment having an average particle size of 0.1 to 20 μm is blended on the resin layer. The outermost layer on the resin layer side is rough so that the surface roughness based on 0601-1994 is 1 μm or more in arithmetic average roughness (Ra) and 8 μm or more in 10-point average roughness (Rz). A method for producing a release paper for pressure-sensitive adhesive sheets. The surface roughness of the cooling roll is 1.13 to 7.80 μm in arithmetic average roughness (Ra) and 7.42 to 37.10 μm in ten-point average roughness (Rz). The manufacturing method of the release paper for adhesive sheets described in 2.