JP2006116718A - Polyolefin laminated paper for release paper, release paper and pressure-sensitive adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide polyolefin laminated paper for release paper capable of suppressing or preventing the release between a paper base material and a polyolefinic resin layer even if heat treatment is applied. <P>SOLUTION: The polyolefin laminated paper for the release paper is constituted by forming the polyolefinic resin layer at least on one side of the paper base material by extrusion laminating processing. The polyolefinic resin layer has a multilayered structure and the layer comprising a polyolefinic resin lowest in density in the polyolefinic resin layer having the multilayered structure is positioned on the side of the paper base material. In the polyolefinic resin layer, the layer on the side of the paper base material is a low density polyethylene layer and the layer on the outer surface side of the paper base material is preferably a medium or high density polyethylene layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyolefin laminated paper for release paper, a release paper, and a pressure-sensitive adhesive sheet.

  Conventionally, as a release paper, a polyolefin resin such as a polyethylene resin is laminated on a paper substrate by an extrusion laminating method, and then a thermosetting silicone release agent on the polyolefin resin layer (polyolefin laminate layer). The thing which apply | coated release agents, such as this, and hardened | cured by heat hardening etc. and formed the release agent is known (refer patent document 1). Accordingly, polyolefin laminated paper (polyolefin laminated paper for release paper) in which a polyolefin resin layer is formed on a paper base material by a laminating method is used as a base material (base material for release paper) in release paper. In such release paper, the polyolefin resin layer is used for the purpose of preventing the thermosetting silicone release agent from penetrating into the paper substrate when a release agent such as a thermosetting silicone release agent is applied. Usually, it is formed with a thickness of 10 to 30 μm.

  Also, the release paper is formed by evaporating the volatile components in the adhesive when the release agent layer is formed with a thermosetting release agent such as a thermosetting silicone release agent, or after applying the adhesive on the release paper. When the pressure-sensitive adhesive layer is formed, it may be heated to a temperature near the melting point of the polyolefin resin (polyethylene resin or the like) constituting the polyolefin resin layer. During such heating, the polyolefin-based resin constituting the polyolefin-based resin layer is melted or softened, and the volatile component mainly containing water is evaporated to evaporate the polyolefin-based resin layer. Peeling may occur between the resin layer and the paper substrate. Generation | occurrence | production of such peeling of a polyolefin resin layer and a paper base material is greatly related with the adhesiveness between a polyolefin resin layer and a paper base material.

  There are two types of factors relating to the adhesion between the polyolefin-based resin layer and the paper substrate: physical factors and chemical factors. The physical factor is derived from the fact that the melted polyolefin resin flows into the voids on the surface of the paper base material, entangled and fixed. On the other hand, the chemical factor is derived from the fact that a polar group is generated on the surface of the paper base material by surface treatment such as corona discharge treatment or anchor coat treatment, and adhesion is improved by this polar group.

  As a paper base material, for example, kraft paper has many surface irregularities, and the adhesiveness between the polyolefin resin layer and the paper base material is good due to physical factors. However, paper substrates such as high-quality paper, glassine paper, and coated paper have relatively few surface irregularities, and adhesion between a polyolefin resin layer and a paper substrate (paper substrate with relatively few surface irregularities). The nature is low. Thus, when forming a polyolefin-based resin layer on a paper substrate having relatively small surface irregularities, the temperature (resin temperature) at the time of forming the polyolefin-based resin layer is raised, Although a technique for improving the flow into the voids on the surface of the resin has been studied, thermal degradation of the polyolefin resin occurs. Further, the technique for improving the adhesiveness by the anchor coating treatment is not practical for economic reasons.

JP-A-2-191796

Accordingly, an object of the present invention is to provide a polyolefin-laminated paper for release paper that can suppress or prevent peeling between the paper substrate and the polyolefin resin layer even when heat treatment is performed.
Another object of the present invention is that even if a polyolefin laminated paper for release paper is used as the release paper substrate, no peeling occurs between the paper substrate and the polyolefin resin layer during heat treatment, An object is to provide a release paper having high quality and high reliability, and a pressure-sensitive adhesive sheet using the release paper.

  As a result of intensive studies to achieve the above object, the present inventors have determined that a polyolefin laminated paper for release paper is formed by laminating a polyolefin resin layer on at least one surface of a paper substrate by extrusion lamination. The polyolefin resin layer formed by extrusion laminating method on the paper substrate has a multilayer structure, and the layer on the paper substrate side in the polyolefin resin layer (that is, the polyolefin resin layer in contact with the paper substrate) The structure of the polyolefin resin layer with the lowest density among the polyolefin resin layers with a multilayer structure effectively suppresses peeling between the paper substrate and the polyolefin resin layer even after heat treatment. Or found that it can be prevented. The present invention has been completed based on these findings.

  That is, the present invention is a polyolefin laminated paper for release paper having a configuration in which a polyolefin resin layer is formed by extrusion lamination on at least one surface of a paper substrate, and the polyolefin resin layer has a multilayer structure. A polyolefin laminated paper for release paper, characterized in that, among the polyolefin resin layers having a multilayer structure, the lowest density polyolefin resin layer is located on the paper substrate side. provide.

  In the present invention, the paper substrate side layer in the polyolefin resin layer is preferably a low density polyethylene layer, and the outer surface side layer in the polyolefin resin layer is a medium density polyethylene layer or a high density polyethylene layer. A layer is preferred.

  Moreover, in this invention, it is preferable that the total thickness of a polyolefin-type resin layer is 10-30 micrometers. The thickness of the layer on the paper base side in the polyolefin resin layer may be 5 to 15 μm, and the thickness of the layer on the outer surface side in the polyolefin resin layer may be 5 to 25 μm.

  According to the present invention, there is provided a release paper having a configuration in which a release agent layer is formed on at least one surface of a release paper base material, wherein the release paper base material is the polyolefin laminated paper for release paper. And a release paper characterized in that a release agent layer is formed on the polyolefin resin layer surface or the paper substrate surface of the polyolefin laminate paper for release paper. In this release paper, a release agent layer may be formed by applying a release agent on a polyolefin laminated paper for release paper and then performing a heat treatment.

  The present invention also includes a pressure-sensitive adhesive sheet having an adhesive layer, wherein the release paper is laminated on the adhesive layer so that the adhesive layer and the release agent layer are in contact with each other. Also included is a pressure sensitive adhesive sheet characterized by In the pressure-sensitive adhesive sheet, the adhesive layer may be formed by applying a pressure-sensitive adhesive on the release paper and then performing a heat treatment.

  According to the polyolefin laminated paper for release paper of the present invention, peeling between the paper substrate and the polyolefin resin layer can be suppressed or prevented even when heat treatment is performed. Therefore, even when polyolefin release paper for release paper is used as the release paper substrate, there is no separation between the paper substrate and the polyolefin resin layer during heat treatment, and high quality and high reliability. A release paper and a pressure-sensitive adhesive sheet using the release paper are obtained.

  Hereinafter, the present invention will be described in detail with reference to the drawings as necessary. In addition, about the same member or site | part, the same code | symbol may be attached | subjected.

(Polyolefin laminated paper for release paper)
As shown in FIG. 1, the polyolefin laminated paper for release paper of the present invention is formed by laminating a polyolefin-based resin layer having a multilayer structure on at least one surface of a paper substrate by extrusion laminating, and the multilayer Among the polyolefin resin layers having a structure, a layer made of the lowest density polyolefin resin (sometimes referred to as “lowest density polyolefin resin layer”) is located on the paper substrate side (in the polyolefin resin layer). It is a layer on the paper substrate side). FIG. 1 is a schematic sectional view showing a polyolefin laminated paper for release paper of the present invention, and FIG. 1 (a) is a polyolefin laminate for release paper having a structure in which a polyolefin resin layer having a multilayer structure is formed on both sides of a paper substrate. FIG. 1B shows a polyolefin laminated paper for release paper having a structure in which a polyolefin-based resin layer having a multilayer structure is formed on one side of a paper base material. 1 (a) and 1 (b), 1 and 11 are polyolefin laminated papers for release paper, 2 is a paper substrate, 3 is a polyolefin resin layer having a multilayer structure, and 3a is a polyolefin resin on the paper substrate side. The resin layer 3b is a polyolefin resin layer on the outer surface side. The polyolefin resin constituting the polyolefin resin layer 3a has a lower density than the polyolefin resin constituting the polyolefin resin layer 3b. The polyolefin laminated paper 1 for release paper shown in FIG. 1 (a) has a configuration in which a polyolefin resin layer 3a and a polyolefin resin layer 3b are formed in this order on both sides of a paper substrate 2, respectively. Yes. Further, the polyolefin laminated paper 11 for release paper shown in FIG. 1B has a configuration in which a polyolefin resin layer 3a and a polyolefin resin layer 3b are formed in this order on one surface of the paper substrate 2. is doing. 1A and 1B, the polyolefin resin layer 3 having a multilayer structure is a laminate of the polyolefin resin layer 3a and the polyolefin resin layer 3b.

  Examples of the polyolefin resin constituting the polyolefin resin layer having such a multilayer structure include polyethylene (for example, low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, etc.), polypropylene, polybutene [poly (1 -Butene etc.], polypentene [poly (1-pentene) etc.], poly (4-methyl-1-pentene), α-olefin copolymer [ethylene-propylene copolymer or ethylene- (1-butene) Copolymers of ethylene such as copolymers and α-olefins having 3 to 10 carbon atoms; Copolymers of propylene and α-olefins having 4 to 10 carbon atoms such as propylene- (1-butene) copolymers Etc.]. Moreover, as polyolefin resin, the copolymer of components other than ethylene and an alpha olefin can also be used. Polyolefin resins can be used alone or in combination of two or more.

  As the polyolefin resin, polyethylene can be preferably used particularly from the viewpoint of processability and the like.

  It is important that the polyolefin resin layer having a multilayer structure has a structure in which a plurality of layers are laminated. At this time, the number of laminated layers is not particularly limited as long as it is 2 or more, and is preferably 2 to 4 layers, more preferably 2 to 3 layers, and particularly 2 layers. Is preferred.

  Further, as described above, the polyolefin-based resin layer having a multilayer structure is formed in such a form that the lowest-density polyolefin-based resin layer is located on the paper substrate side (that is, a form in contact with the paper substrate). This is very important. Thus, if the lowest density polyolefin-based resin layer is formed so as to be located on the paper substrate side, another density-based polyolefin resin layer (a layer made of the polyolefin resin having the lowest density) is positioned. The site is not particularly limited.

  Therefore, the polyolefin resin layer having a multilayer structure formed on the paper substrate is a multilayer structure in which a plurality of polyethylene layers having different densities are laminated so that the lowest density polyethylene layer is located on the substrate side. It is suitable to have. Specifically, in the polyolefin resin layer having a multilayer structure, for example, the layer on the paper substrate side is a low-density polyethylene layer, a linear low-density polyethylene layer, or a medium-density polyethylene layer, and the outer surface-side layer (on the substrate) The layer on the opposite side) is a high-density polyethylene layer, the layer on the paper substrate side is a low-density polyethylene layer or a linear low-density polyethylene layer, and the outer-side layer is a medium-density polyethylene layer or high-density The structure which is a polyethylene layer is mentioned.

In the present invention, as the polyolefin resin layer having a multilayer structure, the layer on the paper substrate side is preferably a low density polyethylene layer. In the present invention, low density polyethylene means polyethylene having a density of 0.880 (g / cm ³ ) or more and less than 0.930 (g / cm ³ ). The density of the low density polyethylene is a value measured according to JIS K7112 (Method A).

Therefore, it can be said that the low density polyethylene layer as the layer on the paper substrate side is a layer made of polyethylene having a density of 0.880 (g / cm ³ ) or more and less than 0.930 (g / cm ³ ). As the layer on the paper substrate side in the polyolefin-based resin layer having a multilayer structure, a layer made of low-density polyethylene having a density of 0.917 to 0.925 (g / cm ³ ) is suitable among the low-density polyethylene layers.

  In the present invention, in the polyolefin resin layer having a multilayer structure, the outer surface layer is preferably a layer made of a higher density polyolefin resin, and in particular, a polyolefin having a high melting point and a melting point of 130 ° C. or higher. A layer made of a resin (for example, a medium density polyethylene layer or a high density polyethylene layer) is preferable. As a polyolefin-type resin, melting | fusing point is low, so that a density is low normally, for example, melting | fusing point of low density polyethylene is about 100-110 degreeC. Accordingly, if the paper substrate has a structure in which only low-density polyethylene is laminated, the low-density polyethylene layer will melt or soften when the temperature exceeds 100 to 110 ° C. The surface may become cloudy, and the convex part of the paper substrate may be exposed to generate pinholes. The heating process for forming the release agent layer and the pressure-sensitive adhesive layer may be performed at a temperature equal to or higher than the melting point of the low-density polyethylene, and in particular, the heating process for forming the pressure-sensitive adhesive layer is a low volatility in recent years. There is an interest in measures against organic compounds (VOC), and a heating process at a higher temperature is desired. Therefore, by providing a layer made of a higher-density polyolefin resin (particularly a layer made of a higher-density polyolefin resin having a melting point of 130 ° C. or higher) as a layer on the outer surface on the lower-density polyolefin resin layer. Even if heat treatment is performed at a higher temperature (for example, 120 to 130 ° C.), the polyolefin resin layer can be prevented from melting or softening, and the surface of the polyolefin resin layer is fogged or pinholes are generated. Can be suppressed or prevented, and the heating step for forming the pressure-sensitive adhesive layer can be performed at a higher temperature.

In the present invention, as the polyolefin-based resin layer having a multilayer structure, the outer surface layer is preferably a medium density polyethylene layer or a high density polyethylene layer. In the present invention, the medium density polyethylene layer means polyethylene having a density of 0.930 (g / cm ³ ) or more and less than 0.940 (g / cm ³ ). The high density polyethylene means polyethylene having a density of 0.940 (g / cm ³ ) or more and less than 0.970 (g / cm ³ ). The density of medium density polyethylene or high density polyethylene is a value measured according to JIS K7112 (A method).

Therefore, it can be said that the medium density polyethylene layer or the high density polyethylene layer as the outer surface side layer is a layer made of polyethylene having a density of 0.930 (g / cm ³ ) or more and less than 0.970 (g / cm ³ ). . As a layer on the outer surface side of the polyolefin-based resin layer having a multilayer structure, among medium density polyethylene layers or high density polyethylene layers, medium density polyethylene or high density polyethylene having a density of 0.930 to 0.950 (g / cm ³ ). The layer according to is preferred.

  In a polyolefin-based resin, the melt index (or melt flow rate; sometimes referred to as “MFR”) used as a standard indicating the viscosity and flowability of the resin is 10 (g / 10 minutes) from the viewpoint of processability and the like. It is preferable that From the viewpoint of physical factors that determine the adhesion to the paper substrate, a higher MFR is considered advantageous. However, a polyolefin resin having an MFR value that is too high makes the neck-in large and difficult to handle.

  In the present invention, the polyolefin resin layer is formed by extrusion lamination. As a method for extrusion lamination of such a polyolefin resin, a forming method using various extrusion molding machines using various dies such as a T die can be employed. As an extrusion laminating method, specifically, a method in which a plurality of polyethylene-based resins are individually melted and formed using a multi-layer laminating die having an internal slit that is simultaneously extruded on a paper substrate is efficient and preferable. However, it is also possible to adopt a method in which each layer is sequentially formed in a tandem laminating apparatus having a plurality of extrusion coating apparatuses.

  In the extrusion laminating process of polyolefin resin, the extrusion laminating conditions can be appropriately selected according to the type of polyolefin resin and the like. For example, when polyethylene is used as the polyolefin-based resin, the extrusion temperature of polyethylene is preferably 300 to 340 ° C. under the die of the extruder. When the resin temperature is less than 300 ° C., the polyethylene film is likely to be broken, and the adhesion between the paper substrate and the polyethylene layer is lowered. On the other hand, when the resin temperature exceeds 340 ° C., thermal degradation of polyethylene may occur.

  The total thickness of the polyolefin resin layer formed by extrusion laminating (thickness of the entire polyolefin resin layer or the total thickness of the polyolefin resin layer) is not particularly limited, but is, for example, in the range of 10 to 30 μm. The thickness is preferably 15 to 25 μm. When the total thickness of the polyolefin resin layer is less than 10 μm, it becomes difficult to prevent the generation of pinholes, while when it exceeds 30 μm, the cost increases.

  Further, in the polyolefin-based resin layer having a multilayer structure, the thickness of the layer on the paper substrate side is not particularly limited, but is preferably in a range not exceeding the total thickness of other layers. Specifically, the thickness of the layer on the paper substrate side is, for example, in the range of 15 μm or less (for example, 5 to 15 μm), and preferably 5 to 12.5 μm.

  Furthermore, in the polyolefin resin layer having a multilayer structure, the thickness of the outer surface side layer is not particularly limited, but is, for example, in the range of 5 to 25 μm, and preferably 5 to 16.7 μm.

  The paper base material is not particularly limited as long as it is a paper base material, and examples thereof include high-quality paper, glassine paper, coated paper, craft paper, Kurpack paper, and bleached Kurpack paper. Among such paper base materials, in particular, when high-quality paper, glassine paper, or coated paper is used, the effect or action of the present invention is effectively exhibited.

The basis weight of the paper substrate is not particularly limited, but is usually 50 to 100 (g / m ² ), preferably 50 to 80 (g / m ² ).

  Moreover, it does not specifically limit as thickness of a paper base material, For example, it can select from the range of 50-150 micrometers (preferably 50-120 micrometers).

  The paper substrate may have either a single layer structure or a multilayer structure, but usually has a single layer structure.

  In the paper substrate, the surface on which the polyolefin resin layer is formed is preferably subjected to surface treatment such as corona discharge treatment, flame treatment, plasma treatment and the like. Prior to forming the polyolefin resin layer on at least one surface of the paper substrate by extrusion laminating, the surface of the paper substrate on which the polyolefin resin layer is formed is subjected to the surface treatment as described above. As a result, the polyolefin resin layer can be formed on the paper substrate with even better adhesion.

  As shown in FIGS. 1 (a) and 1 (b), the polyolefin laminated paper for release paper of the present invention has a polyolefin resin layer having a multilayer structure on both sides of a paper substrate, and a minimum density polyolefin resin layer is a paper base. It may have a configuration that is formed in contact with the material, with the polyolefin resin layer having a multilayer structure on one side (one side) of the paper substrate, and the lowest density polyolefin resin layer in contact with the paper substrate. You may have the structure formed in the form to do. The polyolefin laminated paper for release paper is used as a base material for release paper. Therefore, when the polyolefin laminated paper for release paper has a configuration in which a polyolefin resin layer having a multilayer structure is formed on both sides of the paper substrate, and the lowest density polyolefin resin layer is in contact with the paper substrate Usually, it is used as a release paper substrate in a release paper having a configuration in which both sides are release surfaces, but can also be used as a release paper substrate in a release paper having a configuration in which only one side is a release surface. . Further, the polyolefin laminated paper for release paper has a configuration in which a polyolefin resin layer having a multilayer structure is formed on one surface of a paper substrate, and the lowest density polyolefin resin layer is in contact with the paper substrate. In general, it is used as a release paper substrate in a release paper having a configuration in which only one side is a release surface, but used as a release paper substrate in a release paper having a configuration in which both sides are release surfaces. You can also.

(Release paper)
As shown in FIG. 2, the release paper of the present invention has a release agent on at least one surface (the polyolefin resin layer surface or the paper substrate surface) of the polyolefin laminate paper for release paper as a release paper substrate. It has the structure in which the layer was formed. FIG. 2 is a schematic cross-sectional view showing the release paper of the present invention, and FIG. 2 (a) shows each polyolefin resin in the polyolefin laminated paper for release paper in which a polyolefin resin layer having a multilayer structure is formed on both sides of the paper substrate. FIG. 2B shows a release paper having a structure in which a release agent layer is formed on the surface of the layer, and FIG. 2B shows a polyolefin in a polyolefin laminated paper for release paper in which a polyolefin resin layer having a multilayer structure is formed on one side of a paper substrate. The release paper of the structure by which the release agent layer was formed in the system resin layer surface is shown. 2A and 2B, 4 is a release agent layer, and 5 and 51 are release papers, respectively. 1, 11, 2, 3, 3a, 3b are the same as described above. The release paper 5 shown in FIG. 2 (a) has a configuration in which a release agent layer 4 is formed on the surface of the polyolefin resin layer 3 of both multilayer structures in the polyolefin laminate paper 1 for release paper. Yes. Further, the release paper 51 shown in FIG. 2B has a configuration in which a release agent layer 4 is formed on the surface of the polyolefin resin layer 3 having a multilayer structure in the polyolefin laminate paper 11 for release paper. Note that the polyolefin laminated paper 1 for release paper in the release paper 5 shown in FIG. 2 (a) is the same as the polyolefin laminated paper 1 for release paper shown in FIG. 1 (a). Moreover, the polyolefin laminated paper 11 for release paper in the release paper 51 shown in FIG. 2 (b) is the same as the polyolefin laminated paper 11 for release paper shown in FIG. 1 (b).

  In such release paper, the release agent constituting the release agent layer is not particularly limited, and is known or commonly used release agent (for example, thermosetting silicone release agent, radiation curable silicone release agent, long chain) An alkyl release agent, a fluorine release agent, etc.) can be appropriately selected and used. As the release agent, a silicone release agent is preferable, and among them, a thermosetting silicone release agent is preferable. As the thermosetting silicone release agent, for example, an organopolysiloxane having a group containing an aliphatic unsaturated bond (such as an alkenyl group) and an organohydrogenpolysiloxane are used, and a platinum compound is used as a catalyst. As a release agent, a release agent that can form a release agent layer can be used.

  In addition, the release agent may have any form such as solvent-based, solvent-free, and emulsion-based, but from the consideration of environmental issues and the abundant lineup of peel strength, it is solventless. A release agent is preferred.

  For the release agent layer, a release agent is applied on a predetermined surface using various coaters, and if necessary, a heat treatment step (thermosetting step, drying step, etc.), an ultraviolet ray or electron beam irradiation step (ultraviolet ray). Or a curing step by irradiation with an electron beam). Specifically, a release agent layer is formed by applying a release agent to the surface of the polyolefin resin layer of the polyolefin laminated paper for release paper or the surface of the paper substrate using various coaters and then applying heat treatment. be able to. As described above, even when heat treatment is performed when the release agent layer is formed, a polyolefin resin layer having a multilayer structure is formed on the paper substrate in a form in which the lowest density polyolefin resin layer is in contact with the paper substrate. Therefore, there is no separation between the paper base material and the polyolefin resin layer, and the polyolefin resin layer is kept in a state of being closely adhered to the paper base material. A highly reliable release paper can be produced.

  The thickness of the release agent layer is not particularly limited, and can be selected from a range of 0.5 to 3.0 μm (preferably 0.5 to 1.0 μm), for example.

  The release paper of the present invention is a polyolefin laminate paper for release paper as a release paper base material, as shown in FIG. 1 (a) or FIG. 2 (a). When having a configuration in which a resin layer is formed, (1a) a configuration in which a release agent layer is formed on each surface of the polyolefin-based resin layer on both sides of the polyolefin laminated paper for release paper, and (1b) for release paper It can be set as the structure by which the release agent layer was formed in the polyolefin resin layer surface of one side in polyolefin laminated paper.

  In addition, the release paper of the present invention has a polyolefin laminated paper for release paper as a release paper base material, as shown in FIG. 1 (b) or FIG. 2 (b). When having a structure in which a polyolefin-based resin layer having a structure is formed, (2a) a structure in which a release agent layer is formed on the surface of the polyolefin-based resin layer on one side of the polyolefin laminated paper for release paper, (2a ) A configuration in which a release agent layer is formed on the surface of the paper base of one side of the polyolefin laminated paper for release paper, and (2c) the surface of the polyolefin resin layer and the surface of the paper base in the polyolefin laminated paper for release paper, respectively. The release agent layer may be formed.

  The release agent layer is preferably formed on the surface of the polyolefin resin layer.

  The total thickness of the release paper can be appropriately set according to the number of release agent layers, the thickness of the polyolefin laminated paper for release paper, and the like. Specifically, for example, when the release paper has the configuration of (1a), it may be 70 to 210 μm (preferably 90 to 170 μm).

  Such release paper can be used to protect the pressure-sensitive adhesive layer in the pressure-sensitive pressure-sensitive adhesive sheet, as shown in FIGS. FIG. 3 is a schematic sectional view partially showing an example of a pressure-sensitive adhesive sheet using the release paper of the present invention. 3 (a) to 3 (c), 6, 61 and 62 are respectively pressure-sensitive adhesive sheets, 7 is an adhesive layer, and 8 is a support substrate (a support substrate for a pressure-sensitive adhesive sheet). 5 is the same as above (release paper). The pressure-sensitive adhesive sheet 6 shown in FIG. 3A has a configuration in which an adhesive layer 7, a support substrate 8, and an adhesive layer 7 are formed in this order on one release agent layer of the release paper 5. have. That is, the pressure-sensitive pressure-sensitive adhesive sheet 6 is a pressure-sensitive pressure-sensitive adhesive sheet (pressure-sensitive pressure-sensitive adhesive sheet with a base material) having a structure in which the pressure-sensitive adhesive layer 7 is formed on both surfaces of the support base material 8. The release paper 5 is provided on one pressure-sensitive adhesive layer 7 in 7). In the pressure-sensitive adhesive sheet 6, the surface of the pressure-sensitive adhesive layer 7 on the side where the surface is exposed and the surface of the release agent layer on which the release paper 5 is exposed (the surface of the release agent layer on the other side) are in contact. In such a manner, the surface of the pressure-sensitive adhesive layer 7 on the side where the surface is exposed is brought into contact with the surface of the pressure-sensitive adhesive sheet 6 where the release paper 5 is exposed in the other pressure-sensitive pressure-sensitive adhesive sheet 6. The surface of the pressure-sensitive adhesive layer 7 that is exposed can also be protected by the release paper 5.

  Moreover, the pressure-sensitive adhesive sheet 61 shown in FIG. 3B has an adhesive layer 7, a supporting substrate 8, an adhesive layer 7, and a release paper 5 on one release agent layer of the release paper 5. It has the structure formed in order. That is, the pressure-sensitive pressure-sensitive adhesive sheet 61 is a pressure-sensitive pressure-sensitive adhesive sheet (pressure-sensitive adhesive sheet with a base material) having a structure in which the pressure-sensitive adhesive layer 7 is formed on both surfaces of the support base material 8. 7) A release paper 5 is provided on each of them.

  Further, the pressure-sensitive adhesive sheet 62 shown in FIG. 3C has a configuration in which the adhesive layer 7 is formed on one release agent layer of the release paper 5. That is, the pressure-sensitive pressure-sensitive adhesive sheet 62 is a pressure-sensitive pressure-sensitive adhesive sheet (base-less pressure-sensitive pressure-sensitive adhesive sheet) formed by only the pressure-sensitive adhesive layer 7, and the release paper 5 is provided on one surface of the pressure-sensitive adhesive layer 7. Is provided. The pressure-sensitive adhesive sheet 62 is such that the exposed surface of the adhesive layer 7 and the exposed release agent layer surface of the release paper 5 (the other release agent layer surface) are in contact with each other. It is wound in a roll shape, or is laminated so that the exposed release agent layer surface of the release paper 5 in the other pressure-sensitive adhesive sheet 62 is in contact with the exposed surface of the adhesive layer 7. By doing so, the exposed surface of the pressure-sensitive adhesive layer 7 can also be protected by the release paper 5.

(Pressure-sensitive adhesive sheet)
As shown in FIGS. 3A to 3C, the pressure-sensitive adhesive sheet of the present invention has at least an adhesive layer. On the adhesive layer, the release paper has an adhesive layer and It has the structure laminated | stacked in the form which a release agent layer contacts. That is, it is important that the pressure-sensitive adhesive sheet has at least a configuration in which an adhesive layer is formed on a release paper. Thus, the pressure-sensitive adhesive sheet has at least an adhesive layer, and at least one release paper is used.

  In addition, as described above, the release paper is formed by laminating a polyolefin resin layer having a multilayer structure on at least one surface of the paper base material by extrusion laminating, and among the polyolefin resin layers having the multilayer structure, Since the lowest density polyolefin-based resin layer (lowest-density polyolefin-based resin layer) is a polyolefin-laminated paper for release paper having a configuration located on the paper substrate side, heat treatment is performed. In addition, peeling between the paper substrate and the polyolefin resin layer in the release paper is suppressed or prevented. Therefore, when forming the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer may be applied on the release layer in the release paper, heated, and subjected to heat treatment such as curing or drying to form the pressure-sensitive adhesive layer. In addition, a pressure-sensitive adhesive sheet in which no peeling occurs between the paper substrate and the polyolefin-based resin layer and a high-quality and highly reliable release paper is used can be produced.

  Therefore, the pressure-sensitive adhesive sheet of the present invention can be produced by forming an adhesive layer by applying an adhesive on release paper. Specifically, the pressure-sensitive pressure-sensitive adhesive sheet shown in FIG. 3A is a pressure-sensitive adhesive sheet on which a pressure-sensitive adhesive is applied, and then a heat treatment (thermosetting or drying) is performed to form a pressure-sensitive adhesive layer. Furthermore, a support base material is bonded onto the pressure-sensitive adhesive layer, and then a pressure-sensitive adhesive is applied onto the support base material, followed by heat treatment (thermosetting treatment or drying treatment) to form a pressure-sensitive adhesive layer. Can be produced. In addition, the pressure-sensitive adhesive sheet shown in FIG. 3 (a) is formed by applying a pressure-sensitive adhesive on release paper, and then performing heat treatment (thermosetting or drying) to form a pressure-sensitive adhesive layer. A support substrate is bonded onto the pressure-sensitive adhesive layer, and then the pressure-sensitive adhesive layer formed on the process paper or other release paper is bonded to the surface of the support substrate, and the process paper or other release paper is peeled off. It can also be produced by removing it.

  In addition, the pressure-sensitive adhesive sheet shown in FIG. 3B is a pressure-sensitive adhesive sheet on which a pressure-sensitive adhesive is applied, and then a heat treatment (thermosetting or drying) is performed to form a pressure-sensitive adhesive layer. A support base material is bonded onto the pressure-sensitive adhesive layer, and then a pressure-sensitive adhesive is applied onto the support base material, followed by heat treatment (thermal curing treatment or drying treatment) to form a pressure-sensitive adhesive layer. It can be produced by laminating release paper on the adhesive layer. In addition, the pressure-sensitive adhesive sheet shown in FIG. 3B is a pressure-sensitive adhesive sheet on which a pressure-sensitive adhesive is applied, and then a heat treatment (thermosetting or drying) is performed to form a pressure-sensitive adhesive layer. It can also be produced by laminating a support substrate on the pressure-sensitive adhesive layer, and then laminating a pressure-sensitive adhesive layer formed on a process paper or other release paper on the surface of the support substrate.

  Further, the pressure-sensitive adhesive sheet shown in FIG. 3 (c) is prepared by applying an adhesive on release paper and then applying heat treatment (thermosetting or drying) to form an adhesive layer. can do.

  As described above, the pressure-sensitive adhesive sheet of the present invention is preferably a pressure-sensitive adhesive sheet having both adhesive surfaces, but may be a pressure-sensitive adhesive sheet having only one adhesive surface. As described above, at least one release paper (one or two) is used as the release paper.

  The pressure-sensitive adhesive sheet is either a pressure-sensitive adhesive sheet having a supporting substrate (pressure-sensitive adhesive sheet with a substrate) or a pressure-sensitive adhesive sheet having no supporting substrate (substrate-less pressure-sensitive adhesive sheet). May be.

  Furthermore, the pressure-sensitive pressure-sensitive adhesive sheet of the present invention includes, for example, a plurality of pressure-sensitive pressure-sensitive adhesive sheets obtained by superimposing a release agent layer surface of a release paper on another pressure-sensitive pressure-sensitive adhesive sheet on the pressure-sensitive adhesive layer surface of the pressure-sensitive pressure-sensitive adhesive sheet. May be a pressure-sensitive pressure-sensitive adhesive sheet in a stacked form, or may be a pressure-sensitive pressure-sensitive adhesive tape wound in a roll shape. In the pressure-sensitive adhesive tape, for example, after the pressure-sensitive adhesive layer is formed in a predetermined layer configuration on the release paper, the exposed pressure-sensitive adhesive layer surface is brought into contact with the release agent layer surface of the other release paper. It can be manufactured by being rolled up in a roll shape.

  In addition, as a support base material in a pressure-sensitive adhesive sheet, for example, polyolefin resin such as polypropylene, ethylene-propylene copolymer, polyethylene, poly-4-methylpentene-1, polyester such as polyethylene terephthalate, styrene such as polystyrene, etc. Plastic film and sheet made of thermoplastic resin such as polyvinyl resin, polyvinyl chloride and the like, and foams thereof; papers such as Japanese paper and kraft paper; cloths such as cotton cloth and soft cloth; non-woven cloth such as polyester nonwoven cloth and vinylon nonwoven cloth A metal foil such as an aluminum foil, a stainless steel foil, or a copper foil; and a laminate thereof.

  As the supporting substrate, a plastic film or sheet can be suitably used. The plastic film or sheet may have any form of non-stretching and stretching (uniaxial stretching and biaxial stretching).

  In the supporting base material, the surface on the side where the pressure-sensitive adhesive layer is formed may be subjected to various surface treatments (such as undercoating with an undercoating agent, corona discharge treatment) as necessary.

  The thickness of the support substrate can be appropriately selected within a range that does not impair the handleability and the like, but is generally 5 to 300 μm, preferably 10 to 200 μm.

  In addition, as the pressure-sensitive adhesive (pressure-sensitive adhesive) constituting the pressure-sensitive adhesive layer (pressure-sensitive adhesive layer) in the pressure-sensitive pressure-sensitive adhesive sheet, various pressure-sensitive adhesives can be appropriately selected and used. One preferred pressure sensitive adhesive is a poly (meth) acrylic acid ester pressure sensitive adhesive (acrylic pressure sensitive adhesive). This pressure-sensitive adhesive is mainly composed of an acrylic polymer obtained by a polymerization method such as a solution polymerization method or an emulsion polymerization method, and if necessary, a crosslinking agent, a tackifier, a softener, an anti-aging agent, a filler. It is prepared by adding various additives such as. The acrylic polymer is mainly composed of, for example, an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms such as ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like. And a monomer mixture obtained by adding other monomers such as 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid, styrene, and vinyl acetate as a modifying monomer that can be copolymerized if necessary. be able to. According to the acrylic pressure-sensitive adhesive mainly composed of these acrylic polymers, extremely good results can be obtained in terms of peelability.

  The form of the pressure-sensitive adhesive is not particularly limited, but in terms of handleability and the like, forms such as a solvent system, an emulsion system, and a hot melt system (solvent-free system) are common. In addition, the acrylic pressure-sensitive adhesives may be used alone or in combination of two or more pressure-sensitive adhesives as long as the performance as a pressure-sensitive adhesive is not impaired. An agitated blend may be used.

  The thickness in particular of a pressure sensitive adhesive layer is not restrict | limited, For example, it can select suitably from the range of 10-200 micrometers (preferably 20-150 micrometers).

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following, “parts” means parts by weight.

Example 1
Corona discharge treatment was performed on both sides of a paper substrate (trade name “ONE78” manufactured by Oji Paper Co., Ltd .; basis weight 78 g / m ² ). A diameter of 90 mm, L / L so that a low density polyethylene layer (thickness: 12.5 μm) and a medium density polyethylene layer (thickness: 12.5 μm) are formed on one side of the paper substrate from the paper substrate side. Using a multilayer laminate die equipped with an extruder having two D = 32 screws (the temperature of the screw and die is set so that the resin temperature immediately below the die is 325 ° C.), the low density polyethylene layer is Low density polyethylene for forming [trade name “Suntech-LD L1885” manufactured by Asahi Kasei Corporation; density: 0.918 g / cm ³ , melt index (MFR): 9.0 g / 10 min; in Table 1, “LDPE” Medium density polyethylene for forming a medium density polyethylene layer [trade name “Suntech-LD L4490” manufactured by Asahi Kasei Corporation; density: 0 939 g / cm ^3, a melt index (MFR): 8.3g / 10 min; in Table 1 may be referred to as "MDPE"] and extruding were extrusion lamination. Therefore, the polyolefin resin layer is composed of a low density polyethylene layer and a medium density polyethylene layer, and the thickness (total thickness) is 25 μm.

  Also, the other surface of the paper substrate is similarly extruded and laminated using the low density polyethylene and the medium density polyethylene. From the paper substrate side, a low density polyethylene layer (thickness: 12.5 μm), A density polyethylene layer (thickness: 12.5 μm) was formed.

Furthermore, a solvent-free thermosetting silicone release agent was applied to the surface of the polyolefin resin layer formed on both sides of the paper substrate so that the adhesion amount was 1 g / m ^2, and dried with hot air ( 120 ° C. × 1 minute), release paper having a layer structure as shown in FIG. 2A (release agent layer / medium density polyethylene layer / low density polyethylene layer / paper substrate / low density polyethylene layer / medium) Density polyethylene layer / release agent layer).

(Comparative Example 1)
After corona discharge treatment was performed on both sides of a paper substrate (trade name “ONE78” manufactured by Oji Paper Co., Ltd .; basis weight 78 g / m ² ), a medium density polyethylene layer (thickness: 25 μm), a medium density polyethylene layer using a multilayer laminate die similar to Example 1 (the temperature of the screw and die is set so that the resin temperature immediately below the die is 325 ° C.). Medium density polyethylene [trade name “Suntech-LD L4490” manufactured by Asahi Kasei Corporation; density: 0.939 g / cm ³ , melt index (MFR): 8.3 g / 10 min; MDPE] Extrusion lamination was performed. Therefore, the polyolefin-based resin layer is composed only of a medium density polyethylene layer, and its thickness (total thickness) is 25 μm.

  In addition, the other surface of the paper substrate was similarly extruded and laminated using the medium density polyethylene to form a medium density polyethylene layer (thickness: 25 μm).

Further, a solvent-free thermosetting silicone release agent was applied to the surface of the polyolefin resin layer (medium density polyethylene layer) formed on both sides of the paper substrate in the same manner as in Example 1 at an adhesion amount of 1 g / the coating is m ^2, by performing hot air drying (120 ° C. × 1 min) to prepare a release paper (release agent layer / medium density polyethylene layer / paper substrate / medium density polyethylene layer / release agent layer) .

(Comparative Example 2)
After corona discharge treatment was performed on both sides of a paper substrate (trade name “ONE78” manufactured by Oji Paper Co., Ltd .; basis weight 78 g / m ² ), a medium density polyethylene layer (thickness: Medium density polyethylene layer using the same multilayer laminate die as in Example 1 (the temperature of the screw and die is set so that the resin temperature immediately below the die is 335 ° C.) Medium density polyethylene [trade name “Suntech-LD L4490” manufactured by Asahi Kasei Corporation; density: 0.939 g / cm ³ , melt index (MFR): 8.3 g / 10 min; MDPE] Extrusion lamination was performed. Therefore, the polyolefin-based resin layer is composed only of a medium density polyethylene layer, and its thickness (total thickness) is 25 μm.

  In addition, the other surface of the paper substrate was similarly extruded and laminated using the medium density polyethylene to form a medium density polyethylene layer (thickness: 25 μm).

Further, a solvent-free thermosetting silicone release agent was applied to the surface of the polyolefin resin layer (medium density polyethylene layer) formed on both sides of the paper substrate in the same manner as in Example 1 at an adhesion amount of 1 g / the coating is m ^2, by performing hot air drying (120 ° C. × 1 min) to prepare a release paper (release agent layer / medium density polyethylene layer / paper substrate / medium density polyethylene layer / release agent layer) .

(Comparative Example 3)
After performing corona discharge treatment on both sides of a paper base (trade name “ONE78” manufactured by Oji Paper Co., Ltd .; basis weight 78 g / m ² ), a low density polyethylene layer (thickness: 25 μm), a low-density polyethylene layer using a multilayer laminate die similar to Example 1 (the temperature of the screw and die is set so that the resin temperature immediately below the die is 325 ° C.) Low density polyethylene [trade name “Suntech-LD L1885” manufactured by Asahi Kasei Co., Ltd .; density: 0.918 g / cm ³ , melt index (MFR): 9.0 g / 10 min; LDPE], Extrusion lamination was performed. Accordingly, the polyolefin-based resin layer is composed only of a low-density polyethylene layer, and its thickness (total thickness) is 25 μm.

  Further, the other surface of the paper base material was extruded and laminated in the same manner using the low-density polyethylene to form a low-density polyethylene layer (thickness: 25 μm).

Further, a solvent-free thermosetting silicone release agent was applied to the surface of the polyolefin resin layer (low density polyethylene layer) formed on both sides of the paper substrate in the same manner as in Example 1 with an adhesion amount of 1 g / was applied so that the m ^2, by performing a hot-air drying (120 ° C. × 1 min) to prepare a release paper (release agent layer / low density polyethylene layer / paper substrate / low density polyethylene layer / release agent layer) .

(Evaluation)
About the release paper (width: 1245mm, length: 1000m) obtained by the Example and the comparative example, by the method shown below, the adhesiveness of a paper base material and a polyolefin-type resin layer, and the heat resistance characteristic of a polyolefin-type resin layer are shown. evaluated. The evaluation results are shown in Table 1.

(Evaluation method for adhesion between paper substrate and polyolefin resin layer)
A test piece having a length of 200 mm and a width of 25 mm was cut out from the release paper obtained in Examples and Comparative Examples. One end of this test piece was immersed in an aqueous sodium hydroxide solution having a concentration of 1 N and ethanol up to about 20 mm sequentially for about 1 minute to create a trigger for peeling off the polyolefin resin layer from the paper substrate. . Thereafter, the polyolefin resin layer to be peeled is faced up, the opposite side is fixed to a flat surface with a double-sided adhesive tape, and slowly peeled off by hand at a peeling angle of 90 ° C. Alternatively, the polyolefin-based resin layer surface was visually observed and evaluated according to evaluation criteria in the following four stages.
Evaluation criteria A: Peeled inside the paper substrate.
B: Peeled at the interface between the paper base and the polyolefin resin layer, and paper fibers are adhered to the whole surface of the peeled polyolefin resin layer.
C: Peeled at the interface between the paper substrate and the polyolefin resin layer, and the fiber resin is mostly adhered to the surface of the peeled polyolefin resin layer, but in some places the paper fiber is not adhered. Exists.
D: Peeled at the interface between the paper substrate and the polyolefin resin layer, and no paper fibers are attached to the surface of the peeled polyolefin resin layer.

(Evaluation method for heat resistance of polyolefin resin layer)
A test piece having a length of 200 mm and a width of 300 mm was cut out from the release paper obtained in Examples and Comparative Examples. After leaving this test piece in a 120 ° C. hot air circulation dryer and a 130 ° C. hot air circulation dryer for 3 minutes, respectively, the test piece was taken out from the surface state of the polyolefin resin layer and the paper substrate. The peeled state was visually observed and evaluated according to evaluation criteria in the following three stages.
Evaluation criteria for surface condition ○: No change.
X: Cloudiness (white turbidity) is observed in the polyolefin resin layer.
Evaluation criteria for peeled state ○: No change.
X: Peeling between the paper substrate and the polyolefin resin layer is observed.

  As is clear from the results in Table 1, the release paper according to Example 1 has excellent adhesion of the polyolefin resin layer to the paper substrate, and the polyolefin resin layer is clouded even when heat treatment is performed. It does not occur and adheres to the paper base material layer with good adhesiveness, and no peeling occurs between the base material and the polyolefin resin layer.

It is a schematic sectional drawing which shows the polyolefin laminated paper for release paper of this invention. It is a schematic sectional drawing which shows the release paper of this invention. It is a schematic sectional drawing which shows partially the example of the pressure-sensitive adhesive sheet using the release paper of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polyolefin laminated paper for release paper 11 Polyolefin laminated paper for release paper 2 Paper base material 3 Polyolefin resin layer 3a of multilayer structure 3a Polyolefin resin layer 3b on the paper base side 4 Polyolefin resin layer 4 on the outer side 4 Release agent layer Paper 51 Release paper 6 Pressure sensitive adhesive sheet 61 Pressure sensitive adhesive sheet 62 Pressure sensitive adhesive sheet 7 Adhesive layer 8 Support base material (support base material for pressure sensitive adhesive sheet)

Claims (10)

A polyolefin laminated paper for release paper having a configuration in which a polyolefin resin layer is formed by extrusion laminating on at least one surface of a paper substrate, and the polyolefin resin layer has a multilayer structure A polyolefin-laminated paper for release paper, wherein the polyolefin resin layer having the lowest density among the polyolefin resin layers having a multilayer structure is located on the paper substrate side. 2. The polyolefin-laminated paper for release paper according to claim 1, wherein the layer on the paper substrate side in the polyolefin resin layer is a low density polyethylene layer. The polyolefin laminated paper for release paper according to claim 1 or 2, wherein the outer surface side layer of the polyolefin resin layer is a medium density polyethylene layer or a high density polyethylene layer. The polyolefin laminated paper for release paper according to any one of claims 1 to 3, wherein the total thickness of the polyolefin resin layer is 10 to 30 µm. The polyolefin laminated paper for release paper according to any one of claims 1 to 4, wherein the thickness of the layer on the paper substrate side in the polyolefin resin layer is 5 to 15 µm. The polyolefin laminated paper for release paper according to any one of claims 1 to 5, wherein the thickness of the outer surface layer of the polyolefin resin layer is 5 to 25 µm. It is the release paper which has the structure by which the release agent layer was formed in the at least one surface of the base material for release paper, Comprising: The base material for release paper is described in any one of Claims 1-6. A release paper, characterized in that a release agent layer is formed on the polyolefin resin layer surface or the paper substrate surface of the release paper polyolefin laminate paper. The release paper according to claim 7, wherein the release agent layer is formed by applying a release agent on the polyolefin laminated paper for release paper and then performing a heat treatment. A pressure-sensitive adhesive sheet having an adhesive layer, wherein the release paper according to claim 7 or 8 is laminated on the adhesive layer in a form in which the adhesive layer and the release agent layer are in contact with each other. A pressure-sensitive adhesive sheet characterized by The pressure-sensitive adhesive sheet according to claim 9, wherein the pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive on the release paper and then performing a heat treatment.

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