Anisotropic peeling sheet, and manufacturing method of anisotropic peeling sheet

Abstract

To provide an anisotropic peeling sheet capable of being easily peeled from a direction in which peeling is desired, while suppressing unintended peel-off.SOLUTION: An anisotropic peeling sheet 100 comprises a substrate 10, and a peeling agent layer 30 provided on at least one surface of the substrate 10. The peeling agent layer 30 comprises a resin compound constituted from silylated polyolefin (A), and polyolefin (B). The polyolefin (B) contains polyethylene (B1). When a total amount of the silylated polyolefin (A) and the polyolefin (B) is set to 100 mass%, the silylated polyolefin (A) has a content of 0.1 mass% or more and 3 mass% or less, and the polyethylene (B1) has a content of 90 mass% or more. A laminate is laminated on the peeling agent layer 30; and when the laminate is peeled from the peeling agent layer 30, first peeling force in a first direction, and second peeling force in a second direction are different from each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an anisotropic release sheet and a method for producing an anisotropic release sheet. [Background technology]

[0002] Conventionally, release sheets have been widely used for various applications, such as protective sheets for the adhesive layer of an adhesive sheet, various resin sheets, various composite materials, and process sheets for producing synthetic leather, etc. For example, when a release sheet is used for these applications, a laminate such as an adhesive layer, various resin sheets, various composite materials, and synthetic leather is laminated on the releasable surface of the release sheet.

[0003] The release sheet includes, for example, a substrate and a release agent layer provided on the substrate, and if necessary, a sealing layer may be provided between the substrate and the release agent layer.

[0004] Patent Document 1 describes a release paper in which an ethylene-based resin is laminated on a paper base material by extrusion lamination, and then a thermosetting silicone-based release agent is applied onto the ethylene-based resin layer and heated to harden it to form a release agent layer.

[0005] Patent Document 2 describes a release material having a laminated structure in which a release material substrate and a release agent layer are laminated. The release agent layer is a layer formed from a release agent composition containing a non-silicone thermoplastic resin as a main component and containing a silylated polyolefin. The release agent layer in the release material disclosed in Patent Document 2 is laminated on the adhesive layer of the adhesive sheet. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 02-191796 [Patent Document 2] JP 2020-094099 A Summary of the Invention [Problem to be solved by the invention]

[0007] As described in Patent Document 1, in a release sheet in which a filling layer is provided on a substrate, and a release agent layer containing a silicone-based release agent (hereinafter, the release agent layer containing a silicone-based release agent may be referred to as a silicone-based release agent layer) is provided on the filling layer, the silicone-based release agent layer has excellent releasability with a laminate in contact with the release agent layer. However, depending on the laminate to be laminated on the release agent layer, the silicone-based release agent layer may have too low a peel strength of the laminate against the release agent layer. In addition, a release sheet provided with a filling layer requires an increased number of steps for providing the filling layer.

[0008] On the other hand, the release material described in Patent Document 2 does not provide a sealing layer, and it is possible to provide a release agent layer directly on the substrate. Since the release material described in Patent Document 2 can form a release agent layer without providing a sealing layer, the number of steps when manufacturing a release sheet can be reduced. In addition, the release material described in Patent Document 2 has a release agent layer with a specific configuration, and thus the phenomenon in which the release material floats up from the adhesive layer of a removable adhesive sheet is suppressed.

[0009] For example, in a structure in which a release sheet and a laminate with low tackiness are laminated, if a release sheet with a low peeling strength of the laminate against the release agent layer is used, the peeling strength of the laminate against the release agent layer is too low, so there is a concern that the phenomenon of unintended peeling occurs between the release agent layer and the laminate from either direction. On the other hand, if a release sheet with a high peeling strength of the laminate against the release agent layer is used, the peeling strength of the laminate against the release agent layer is too high, so even if you try to peel the release agent layer and the laminate from either direction, it is difficult to peel the laminate from the release agent layer. For this reason, there are cases where a release sheet is required to be easily peeled from one direction, but to suppress the occurrence of unintended peeling before peeling the laminate from a direction perpendicular to the one direction. For this reason, there is room for further improvement in the release sheet.

[0010] The object of the present invention is to provide an anisotropic release sheet that, when peeling a laminate from the release sheet, can easily peel the laminate from the desired direction while preventing unintended peeling of the laminate, and a method for producing the anisotropic release sheet. [Means for solving the problem]

[0011] [1] An anisotropic release sheet having a first direction and a second direction perpendicular to the first direction, A substrate and a release agent layer provided on at least one surface of the substrate, the release agent layer contains a resin composition composed of a silylated polyolefin (A) and a polyolefin (B) other than the silylated polyolefin (A), The polyolefin (B) contains at least polyethylene (B1), When the total amount of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100 mass%, the content of the silylated polyolefin (A) is 0.1 mass% or more and 3 mass% or less, and the content of the polyethylene (B1) is 90 mass% or more, An anisotropic release sheet in which, when a laminate is laminated on the release agent layer and the laminate is peeled from the release agent layer, the peel force of the release agent layer with respect to the laminate is different between a first peel force in the first direction and a second peel force in the second direction.

[0012] [2] [1] The anisotropic release sheet according to the present invention, The ratio of the second peel force to the first peel force is 1.1 or more. Anisotropic release sheet.

[0013] [3] In the anisotropic release sheet according to [1] or [2], the silylated polyolefin (A) is a copolymer having a structural unit (a1) derived from a hydrosilane compound and a structural unit (a2) derived from a terminal double bond-containing polyolefin, The structural unit (a1) includes one or more structural units represented by the following general formula (1): Anisotropic release sheet.

[0014] [ka]

[0015] (In the general formula (1), R 1 is a hydrocarbon group or a silicon-containing group, Y 1 is an oxygen atom, a sulfur atom, or NR 11 is a group represented by NR 11 In the group represented by the formula: N is a nitrogen atom, and R 11 is a hydrogen atom or a hydrocarbon group, R 1 If there are multiple R 1 are the same or different from each other, R 11 If there are multiple R 11 are the same or different Y 1 If there are multiple Ys, 1 are either identical or different.)

[0016] [4] [1] to [3], wherein the anisotropic release sheet is The silylated polyolefin (A) is a block copolymer. Anisotropic release sheet.

[0017] [5] [1] to [4], wherein the anisotropic release sheet is The resin composition is composed only of the silylated polyolefin (A) and the polyethylene (B1). Anisotropic release sheet.

[0018] [6] [1] to [5], wherein the anisotropic release sheet according to any one of the above items is The thickness of the release agent layer is 8 μm or more and 50 μm or less. Anisotropic release sheet.

[0019] [7] [1] to [6], wherein the anisotropic release sheet is The substrate is one or two of a paper substrate and a resin substrate; Anisotropic release sheet.

[0020] [8] A method for producing the anisotropic release sheet according to any one of [1] to [7], providing the substrate; preparing the resin composition; A step of melt-extruding the resin composition molten at a temperature of 230° C. or more and 330° C. or less onto at least one surface of the substrate; having The substrate is transported along the first direction, The resin composition is laminated onto the substrate being transported. A method for producing an anisotropic release sheet. Effect of the Invention

[0021] According to one aspect of the present invention, it is possible to provide an anisotropic release sheet that, when peeling a laminate from the release sheet, can easily peel the laminate from the desired direction while preventing unintended peeling of the laminate, and a method for manufacturing the anisotropic release sheet. [Brief description of the drawings]

[0022] [Figure 1]1 is a schematic cross-sectional view showing an example of an anisotropic release sheet according to an embodiment of the present invention. [Diagram 2] 1A is a schematic explanatory diagram showing how a laminate laminated on an anisotropic release sheet according to the present embodiment is peeled off in a first direction, and FIG. 1B is a schematic explanatory diagram showing how a laminate laminated on an anisotropic release sheet according to the present embodiment is peeled off in a second direction. [Diagram 3] 1A to 1C are schematic diagrams illustrating an example of a method for producing an anisotropic release sheet according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described in detail.

[0024] [Anisotropic release sheet] The anisotropic release sheet according to this embodiment has a first direction and a second direction that is perpendicular to the first direction.

[0025] In this specification, the second direction perpendicular to the first direction means a direction perpendicular to the first direction, not a thickness direction (i.e., the direction in which the release agent layer is provided on the substrate). In one aspect, the first direction in the anisotropic release sheet according to the present embodiment is preferably the machine direction (MD), which is the longitudinal direction when the anisotropic release sheet is manufactured, and the second direction is preferably the transverse direction (TD), which is the transverse direction when the anisotropic release sheet is manufactured, perpendicular to the machine direction.

[0026] The anisotropic release sheet according to the present embodiment comprises a substrate and a release agent layer provided on at least one surface of the substrate. The release agent layer contains a resin composition composed of a silylated polyolefin (A) and a polyolefin (B) other than the silylated polyolefin (A). The polyolefin (B) contains at least a polyethylene (B1). When the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100% by mass, the content of the silylated polyolefin (A) is 0.1% by mass or more and 3% by mass or less, and the content of the polyethylene (B1) is 90% by mass or more. The anisotropic release sheet according to the present embodiment is configured such that, when a laminate is laminated on the release agent layer and the laminate is peeled off from the release agent layer, the first release force in the first direction and the second release force in the second direction of the release agent layer are different from each other.

[0027] In addition, polyolefin (B) may contain polyolefin (B2) other than polyethylene (B1) in addition to polyethylene (B1). Therefore, the silylated polyolefin (A) and the polyolefin (B) contained in the release agent layer are such that, when the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100 mass%, the content of the silylated polyolefin (A) is 0.1 mass% or more and 3 mass% or less, the content of the polyethylene (B1) is 90 mass% or more and 99.9 mass% or less, and the content of the polyolefin (B2) other than the polyethylene (B1) is 0 mass% or more and 9.9 mass% or less. Details of the release agent layer will be described later.

[0028] In this specification, the laminate does not mean an object having a laminated structure, but refers to an object (e.g., adhesive sheets, various resin sheets, various resin materials, various composite materials, synthetic leather, etc.) that is laminated on the release surface of a release sheet. In other words, the laminate is an object having at least one of a single-layer structure and a laminated structure, and is an object that is laminated on the release surface of a release sheet.

[0029] Conventionally, for example, in a release sheet, when a laminate laminated on a release agent layer is peeled off from the release agent layer, the peeling force of the laminate against the release agent layer may be too low depending on the laminate. In this case, there is a concern that unintended peeling may occur at the interface between the release agent layer and the adhesive layer. For example, such a laminate may have low tackiness. Therefore, in order to prevent unintended peeling of the laminate, it is considered to improve the peeling force of the laminate against the release agent layer. Here, tackiness means a sticky feeling that occurs on the surface of a substance.

[0030] As a method for improving the release force, it is considered to form the release agent layer only from a polyolefin resin. The present inventors have studied forming the release agent layer only from a polyolefin resin, and have found that when the resin used for the release agent layer is formed only from polyethylene, the release force of the laminate against the release agent layer may differ between the release force in the first direction and the release force in the second direction perpendicular to the first direction (hereinafter, the difference between the release force in the first direction and the release force in the second direction may be referred to as anisotropy of the release force). However, when the release agent layer is formed only from polyethylene, even when a laminate with low tackiness is laminated on the release agent layer, the release force of the laminate against the release agent layer is too high. In addition, a conventional release sheet in which a release agent layer formed of a release agent composition containing a release agent such as a silicone-based release agent is provided on a sealing layer formed only from polyethylene in order to improve the release force does not produce anisotropy of the release force.

[0031] Therefore, the inventors have further studied and found that by mixing polyethylene with a small amount of silylated polyolefin as the resin used in the release agent layer, it is possible to obtain a moderate release force while maintaining the anisotropy of the release force. Although the reason why the anisotropic release sheet according to this embodiment exhibits anisotropy of the release force is unclear, the inventors speculate that this is due to the difference in crystallinity between the first direction and the second direction of polyethylene, which is the resin component forming the release agent layer.

[0032] From the above, according to the anisotropic release sheet of this embodiment, by having the above-mentioned configuration, when peeling off the laminate from the release sheet, the laminate can be easily peeled off from the desired direction while preventing unintended peeling of the laminate. Furthermore, according to the anisotropic release sheet of this embodiment, even if a laminate with low tackiness is laminated as the laminate to be laminated on the release agent layer, the same effect is exhibited, and a more remarkable effect is obtained. In this specification, the silicone-based release agent and the silylated polyolefin are distinguished from each other.

[0033] The anisotropic release sheet according to the present embodiment will be described below with reference to the drawings. In the drawings, some parts are shown enlarged or reduced in size to facilitate explanation. Referring to Fig. 1, an example of the anisotropic release sheet according to the present embodiment is shown. Fig. 1 is a schematic cross-sectional view of an anisotropic release sheet 100.

[0034] The anisotropic release sheet 100 shown in FIG. 1 comprises a substrate 10 and a release agent layer 30 provided on the substrate 10, and the release agent layer 30 is provided on one surface (first substrate surface 11) of the substrate 10. In the anisotropic release sheet 100, the first substrate surface 11 and the second release agent layer surface 32 are in direct contact with each other. The first release agent layer surface 31, which is the surface opposite to the second release agent layer surface 32, is the surface of the anisotropic release sheet 100 that has releasability and serves as the release surface. When the anisotropic release sheet 100 is used with a laminate (not shown) laminated on the release agent layer 30, the laminate (not shown) is laminated on the first release agent layer surface 31, which is the release surface of the anisotropic release sheet 100. On the other hand, in the anisotropic release sheet 100, the release agent layer 30 is not provided on the second substrate surface 12, which is the surface opposite to the first substrate surface 11 of the substrate 10, and the second substrate surface 12 is exposed.

[0035] The release agent layer 30 contains a resin composition composed of a silylated polyolefin (A) and a polyolefin (B) other than the silylated polyolefin (A). The polyolefin (B) contains at least a polyethylene (B1). When the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100% by mass, the content of the silylated polyolefin (A) is 0.1% by mass or more and 3% by mass or less, and the content of the polyethylene (B1) is 90% by mass or more.

[0036] When the anisotropic release sheet 100 is used by laminating a laminate (not shown) to the release agent layer 30, the anisotropy of the release force occurs when the laminate is peeled from the release agent layer 30. That is, when the laminate is peeled from the release agent layer 30, a first release force in a first direction (X direction shown in FIG. 1) differs from a second release force in a second direction (Y direction shown in FIG. 1). Here, in this specification, the term "the first peel force and the second peel force are different" refers to a case where the peel forces are different when peeling along the first direction and when peeling along the second direction, respectively, when the peel forces are measured under the same peel speed and peel angle conditions (for example, when the peel speed is 0.3 m / min and the peel angle is 180°).

[0037] Next, the anisotropy of the release force will be described with reference to Figures 2(A) and 2(B). Figures 2(A) and 2(B) show a structure 300 in which a laminate 50 is laminated on the first release agent layer surface 31, which is the release surface of anisotropic release sheet 100. In Fig. 2(A), the laminate 50 laminated on the anisotropic release sheet 100 is peeled from the release agent layer 30 in the direction shown by the arrow R1, thereby peeling the laminate 50 along the X direction. When the laminate 50 is peeled from the release agent layer 30 along the X direction shown in Fig. 2(A), the peel force of the laminate 50 against the release agent layer 30 is a first peel force in a first direction. On the other hand, in Fig. 2(B), the laminate 50 laminated on the anisotropic release sheet 100 is peeled from the release agent layer 30 in the direction shown by the arrow R2, thereby peeling the laminate 50 along the Y direction. When the laminate 50 is peeled from the release agent layer 30 along the Y direction shown in Fig. 2(B), the peel force of the laminate 50 against the release agent layer 30 is a second peel force in the second direction. In the anisotropic release sheet 100, when the laminate 50 is peeled from the release agent layer 30, the first peel force, which is the peel force when peeling along the X direction, is different from the second peel force, which is the peel force when peeling along the Y direction.

[0038] 1, 2(A), and 2(B), the direction in which the release agent layer 30 is provided on the substrate 10 of the anisotropic release sheet 100 and the direction in which the laminate 50 is laminated on the first release agent layer surface 31 are shown as the Z direction. The Z direction is the thickness direction of the anisotropic release sheet 100.

[0039] An example of the anisotropic release sheet according to the present embodiment has been described above with reference to FIG. 1, FIG. 2(A), and FIG. 2(B), but the anisotropic release sheet according to the present embodiment is not limited thereto. The anisotropic release sheet according to the present embodiment may adopt various forms as long as it has the above-mentioned configuration. The anisotropic release sheet 100 has a release agent layer 30 provided on the first substrate surface 11 side of the substrate 10, but for example, a release agent layer 30 (not shown) may be provided not only on the first substrate surface 11 side but also on the second substrate surface 12 side. When the release agent layer 30 is provided on both the first substrate surface 11 and the second substrate surface 12, the release agent layer 30 on the first substrate surface 11 side may be referred to as the first release agent layer, and the release agent layer 30 on the second substrate surface 12 side may be referred to as the second release agent layer. When the release agent layer 30 (second release agent layer) is also provided on the second substrate surface 12, the release agent layer 30 (second release agent layer) provided on the second substrate surface 12 may be in direct contact with the substrate 10. When the release agent layer 30 (second release agent layer) is also provided on the second substrate surface 12, the release agent layer 30 (first release agent layer), substrate 10, and release agent layer 30 (second release agent layer) are laminated in this order in the thickness direction (Z direction shown in Figures 1, 2(A), and 2(B)), and the second release agent layer is provided on the second substrate surface 12 side. In the anisotropic release sheet 100, the release agent layer 30 (first release agent layer) provided on the first substrate surface 11 is in direct contact with the substrate 10, but the release agent layer 30 may have an intermediate layer (not shown) between the substrate 10 and the release agent layer 30. In one embodiment, the anisotropic release sheet may have a first intermediate layer between the first release agent layer and the substrate, and a second intermediate layer between the second release agent layer and the substrate. The first and second directions when a release agent layer 30 (second release agent layer) is also provided on the second substrate surface 12 are the same as the first and second directions when a release agent layer 30 (first release agent layer) is provided on the first substrate surface 11.

[0040] <Base material> The substrate is a substrate that supports the release agent layer. The material of the substrate is not particularly limited as long as it can support the release agent layer. Examples of the substrate material include paper, resin, and metal foil, and these materials may be used alone or in combination of two or more. The substrate may be a single layer or may be a multilayer of two or more layers of the same or different types. The substrate is preferably one or two of a paper substrate and a resin substrate. In this specification, the paper substrate is a substrate formed of paper, and the resin substrate is a resin substrate formed of a resin such as a resin film or a resin sheet.

[0041] Examples of papers used for the paper substrate include kraft paper, medium-quality paper, fine paper, glassine paper, and coated paper (eg, art paper, clay-coated paper, cast-coated paper, etc.).

[0042] Examples of resins used for the resin substrate include polyolefin resins (polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymers, norbornene resins, and ethylene copolymers (ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, etc.)), polyester resins (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, etc.), polyvinyl chloride resins (polyvinyl chloride, vinyl chloride copolymers, etc.), polyurethane, polystyrene, polycarbonate, polyamide, polyimide, and fluororesins.

[0043] The thickness of the substrate is not particularly limited. The thickness of the substrate is preferably, for example, 10 μm or more and 300 μm or less. The thickness of the substrate is more preferably 20 μm or more. The thickness of the substrate is more preferably 200 μm or less.

[0044] When the substrate is a resin substrate, various surface treatments can be performed on the surface of the substrate on which the release agent layer is to be provided in order to improve the adhesion between the substrate and the release agent layer. Examples of the surface treatments include corona treatment, plasma treatment, flame treatment, and ozone treatment. Among these, the surface treatment is preferably corona treatment from the viewpoint of operability and the like.

[0045] <Middle Class> In one aspect, the anisotropic release sheet according to the present embodiment may have an intermediate layer provided on a substrate, and a release agent layer laminated on the intermediate layer. The intermediate layer is a layer that is provided as necessary. Examples of the intermediate layer include an easy-adhesion layer such as a primer layer.

[0046] <Release agent layer> When the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100% by mass, the content of the silylated polyolefin (A) is 0.1% by mass or more and 3% by mass or less. In the anisotropic release sheet according to the present embodiment, the release force of the release agent layer is easily controlled to an appropriate value, and from the viewpoint of preventing unintended peeling of the laminate and facilitating peeling from the desired peeling direction, when the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100% by mass, the content of the silylated polyolefin (A) is preferably 0.3% by mass or more, more preferably 0.4% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 0.6% by mass or more. In the anisotropic release sheet of this embodiment, from the viewpoint of making it easier to exhibit the anisotropy of the release force and to easily peel the laminate from the desired direction while suppressing unintended peeling of the laminate, when the total of the silylated polyolefin (A) and polyolefin (B) in the release agent layer is taken as 100 mass%, the content of silylated polyolefin (A) is preferably 2.5 mass% or less, more preferably 2.3 mass% or less, even more preferably 2.0 mass% or less, even more preferably 1.5 mass% or less, and even more preferably 1.0 mass% or less.

[0047] The polyolefin (B) is a polyolefin other than the silylated polyolefin (A) and contains a polyethylene (B1). The polyolefin (B) is composed of a part or the whole of the polyolefin (B) as a polyethylene (B1). When the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100% by mass, the content of the polyolefin (B) is 97% by mass or more and 99.9% by mass or less. When the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100% by mass, the content of the polyethylene (B1) is 90% by mass or more.

[0048] From the viewpoint of making it easier to exhibit the anisotropy of the release force and making it easier to peel the laminate from the desired peeling direction while suppressing unintended peeling of the laminate, when the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100 mass%, the content of polyethylene (B1) is preferably 93 mass% or more, more preferably 94 mass% or more, even more preferably 95 mass% or more, and even more preferably 96 mass% or more. From the viewpoint of making it easier to exhibit the anisotropy of the release force and making it easier to peel the laminate from the desired peeling direction while suppressing unintended peeling of the laminate, when the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100 mass%, the content of polyethylene (B1) is preferably 99.9 mass% or less, more preferably 99.7 mass% or less, even more preferably 99.5 mass% or less, even more preferably 99 mass% or less, even more preferably 98.5 mass% or less, even more preferably 98 mass% or less, and even more preferably 97 mass% or less.

[0049] In one embodiment, the resin composition constituting the release agent layer is preferably composed only of the silylated polyolefin (A) and the polyethylene (B1), from the viewpoint of making it easier to exhibit the anisotropy of the peel force and making it easier to peel the laminate from the desired peeling direction while suppressing unintended peeling of the laminate.

[0050] In one embodiment, the resin composition constituting the release agent layer may contain a polyolefin (B2) other than the polyethylene (B1) as long as it contains the silylated polyolefin (A) and at least the polyethylene (B1) as the polyolefin (B). In order to more easily exhibit the anisotropy of the peeling force and to easily peel the laminate from the desired peeling direction while suppressing unintended peeling of the laminate, the content of the polyolefin (B2) is preferably 0% by mass or more and 9.9% by mass or less when the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100% by mass. From the same viewpoint, the upper limit of the content of the polyethylene (B2) is more preferably 9.7% by mass or less, and even more preferably 9.5% by mass or less. From the same viewpoint, it is also preferable that the release agent layer does not contain the polyolefin (B2).

[0051] (Silylated polyolefin (A)) The silylated polyolefin (A) is a copolymer having a structural unit (a1) derived from a hydrosilane compound and a structural unit (a2) derived from a terminal double bond-containing polyolefin, and the structural unit (a1) preferably contains one or more structural units represented by the following general formula (1): Hereinafter, the hydrosilane compound may be referred to as the hydrosilane compound (a1'), and the terminal double bond-containing polyolefin may be referred to as the terminal double bond-containing polyolefin (a2').

[0052] The silylated polyolefin (A) contains a -Si-CC- structure resulting from a reaction between -Si-H in the hydrosilane compound (a1') and -C=C (vinyl group) in the terminal double bond-containing polyolefin (a2'). In the silylated polyolefin (A), the polymerization form of the copolymer of the hydrosilane compound (a1') and the terminal double bond-containing polyolefin (a2') is not particularly limited, and may be any of a random copolymer, a block copolymer, and a graft copolymer. The polymerization form of the copolymer of the hydrosilane compound (a1') and the terminal double bond-containing polyolefin (a2') is preferably a block copolymer. That is, the silylated polyolefin (A) is preferably a block copolymer.

[0053] [ka]

[0054] (In the general formula (1), R 1 is a hydrocarbon group or a silicon-containing group, Y 1 is an oxygen atom, a sulfur atom, or NR 11 is a group represented by NR 11 In the group represented by the formula: N is a nitrogen atom, and R 11 is a hydrogen atom or a hydrocarbon group, R 1 If there are multiple R 1 are the same or different from each other, R11 If there are multiple R 11 are the same or different from each other, Y 1 If there are multiple Ys, 1 are either identical or different.)

[0055] In the general formula (1), R 1 is preferably a hydrocarbon group, more preferably an aliphatic hydrocarbon group, still more preferably an alkyl group, even more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group.

[0056] In the general formula (1), Y 1 is preferably an oxygen atom.

[0057] In a copolymer having a structural unit (a1) derived from a hydrosilane compound and a structural unit (a2) derived from a terminal double bond-containing polyolefin, when the structural unit (a1) contains a plurality of structural units represented by the general formula (1), R 1 and Y 1 There are multiple. In the general formula (1), R 1 If there are multiple, R 1 are preferably the same. In the general formula (1), Y 1 If there are multiple, Y 1 are preferably the same.

[0058] The hydrosilane compound (a1') is preferably a compound represented by the following general formula (2).

[0059] [ka]

[0060] (In the general formula (2), R 1 and Y1 is R in the general formula (1). 1 and Y 1 is synonymous with R 2 is a hydrocarbon group, Y 2 is an oxygen atom, a sulfur atom, or NR 12 is a group represented by NR 12 In the group represented by the formula: N is a nitrogen atom, and R 12 is a hydrogen atom or a hydrocarbon group, R 3 and R 4 each independently represents a hydrocarbon group or a group represented by the following general formula (3): m is an integer of 1 to 20, n is an integer of 0 to 20, If n is 1 or more, Z 1 represents a divalent linking group represented by the following general formula (4): If n is 0, Z 1 is a divalent linking group represented by the following general formula (4), or Y 1 and R 4 represents a direct bond of R 1 and R 2 If there are multiple R 1 and R 2 are each independently the same or different, R 11 and R 12 If there are multiple R 11 and R 12 are each independently the same or different, Y 1 and Y 2 If there are multiple Ys, 1 and Y 2 are each independently the same or different.

[0061] In the general formula (2), R 2is preferably an aliphatic hydrocarbon group, more preferably an alkyl group, even more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group.

[0062] In the general formula (2), Y 2 is preferably an oxygen atom.

[0063] In the general formula (2), R is a hydrocarbon group. 3 and R 4 are each independently preferably an aliphatic hydrocarbon group, more preferably an alkyl group, further preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group. However, when n is 0, R 4 is also preferably a hydrogen atom.

[0064] In formula (2), m is preferably an integer of 1 or more and 6 or less. In the general formula (2), n is preferably 0 or 1.

[0065] In the general formula (2), Y 1 and Y 2 If there are multiple, Y 1 and Y 2 are preferably all oxygen atoms.

[0066] [ka]

[0067] (In the general formula (3), R 5 each independently represents a hydrocarbon group; p is an integer between 1 and 100.

[0068] In the general formula (3), R 5are each independently preferably an aliphatic hydrocarbon group, more preferably an alkyl group, even more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group. 5 are preferably the same. In the general formula (3), p is preferably 1.

[0069] [ka]

[0070] (In the general formula (4), R 6 each independently represents a hydrocarbon group; q is an integer between 0 and 500.

[0071] In the general formula (4), R 6 are each independently preferably an aliphatic hydrocarbon group, more preferably an alkyl group, even more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably a methyl group. 6 are preferably the same.

[0072] The hydrosilane compound (a1') is also preferably a compound represented by the following general formula (5).

[0073] [ka]

[0074] In the general formula (5), q has the same meaning as q in the general formula (4).

[0075] The terminal double bond-containing polyolefin (a2') is a terminal double bond-containing polyolefin that contains one or more vinyl groups. The terminal double bond-containing polyolefin (a2') is preferably such that the portion other than the vinyl group of the terminal double bond-containing polyolefin is any one of an ethylene homopolymer chain, a propylene homopolymer chain, and a copolymer chain of two or more olefins selected from the group consisting of olefins having 2 to 50 carbon atoms.

[0076] Among these, the portion other than the vinyl group of the terminal double bond-containing polyolefin is preferably any one of an ethylene homopolymer chain, a propylene homopolymer chain, or a copolymer chain of two or more olefins selected from the group consisting of ethylene, propylene, butene, norbornene, vinylnorbornene, cyclic polyenes having two or more double bonds, and linear polyenes having two or more double bonds, and more preferably any one of an ethylene homopolymer chain, a propylene homopolymer chain, a copolymer chain of an olefin and a diene, a copolymer chain of ethylene and propylene, a copolymer chain of ethylene and norbornene, or a copolymer chain of ethylene and vinylnorbornene.

[0077] The number average molecular weight (Mn) of the terminal double bond-containing polyolefin (a2') is preferably 100 or more and 500,000 or less. The number average molecular weight (Mn) is a value calculated as standard polystyrene, measured by gel permeation chromatography (GPC).

[0078] The silylated polyolefin (A) can be obtained, for example, by reacting a hydrosilane compound (a1') with a terminal double bond-containing polyolefin (a2') in the presence of a transition metal catalyst composition prepared from the hydrosilane compound (a1') and a transition metal halide, as described in, for example, JP-A Nos. 2010-037555 and 2011-026448.

[0079] The quantitative ratio between the hydrosilane compound (a1') and the terminal double bond-containing polyolefin (a2') is not particularly limited and varies depending on the structure of the silylated polyolefin (A) to be produced. The quantitative ratio between the hydrosilane compound (a1') and the terminal double bond-containing polyolefin (a2') is, for example, preferably in the range of 0.01 equivalents or more and 10 equivalents or less, and more preferably in the range of 0.1 equivalents or more and 2 equivalents or less, as the equivalent ratio between the vinyl group in the terminal double bond-containing polyolefin (a2') and the Si-H bond in the hydrosilane compound (a1').

[0080] Specific examples of the silylated polyolefin (A) include an olefin-silicone copolymer having at least one structure selected from the group consisting of a polyorganosiloxane block represented by the following general formula (6), a polyorganosiloxane block represented by the following general formula (7), and a polyorganosiloxane block represented by the following general formula (8). The silylated polyolefin (A) is not limited to these specific examples. The polyorganosiloxane block is also called a silicone block.

[0081] In the following general formulas (6), (7), and (8), q has the same meaning as q described in the above general formula (4). From the viewpoint of easily controlling the peel strength of the laminate from the release agent layer to an appropriate value, the value of q is preferably 5 or more and 200 or less, and more preferably 10 or more and 100 or less. In addition, in the following general formulas (6), (7), and (8), r is an integer of 1 or more. r is preferably 100 or more and 10,000 or less, and more preferably 200 or more and 10,000 or less.

[0082] In the following general formula (6), the following general formula (7), and the following general formula (8), [ ] r Two R in the structural unit derived from the terminal double bond-containing polyolefin (a2') shown in 7 each independently represents a hydrogen atom or a hydrocarbon group. Here, for example, in the following general formula (6), the following general formula (7), and the following general formula (8), [ ] r The structure shown in is an olefin-derived structural unit constituting the terminal double bond-containing polyolefin (a2'). When the olefin is ethylene, two R 7 are both hydrogen atoms. When the olefin is propylene, the two R 7 In the following general formula (6), the following general formula (7), and the following general formula (8), [ ] r When a plurality of structures represented by the formula: are present, the respective values ​​of r may be the same or different.

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] (Polyolefin (B)) [Polyethylene (B1)] The polyolefin (B) contains at least polyethylene (B1). The polyethylene (B1) may be a homopolymer of ethylene or a polyethylene-based resin which is a copolymer obtained by polymerizing polyethylene as a main monomer and an α-olefin having 3 to 18 carbon atoms as a comonomer. In this specification, the polyethylene homopolymer and the polyethylene-based resin are collectively referred to as polyethylene (B1). The polyethylene (B1) may be contained alone or in combination of two or more kinds. Here, the main monomer refers to a monomer which forms a structural unit contained in the largest amount among the structural units derived from each monomer constituting the polymer.

[0087] Polyethylene (B1) has, for example, a density of 0.88 g / cm 3 More than 0.91g / cm 3 Ultra-low density polyethylene, with a density of less than 0.91 g / cm 3 More than 0.93g / cm 3 Low density polyethylene, with a density of less than 0.93 g / cm 3 More than 0.942g / cm 3 Medium density polyethylene with a density of less than 0.942 g / cm 3 More than 0.97g / cm 3 Any of the following high density polyethylenes may be used. The density of the polyethylene can be measured in accordance with JIS K7112:1999. The polyethylene (B1) is preferably a low density polyethylene. The low density polyethylene may be a high pressure low density polyethylene, a metallocene low density polyethylene synthesized using a metallocene catalyst, or a Ziegler-Natta low density polyethylene synthesized using a Ziegler-Natta catalyst.

[0088] When the polyethylene (B1) is a polyethylene-based resin, it may be a copolymer having a structural unit derived from ethylene and a structural unit derived from at least one α-olefin selected from the group consisting of propylene, butene, pentene, hexene, heptene, octene, 4-methyl-1-pentene, etc. In the copolymer, the ethylene content is preferably 85 mol% or more and 99.9 mol% or less in the total amount (100 mol%) of the structural units constituting the copolymer.

[0089] [Polyolefin (B2)] The polyolefin (B2) is not particularly limited as long as it is a polyolefin other than the polyethylene (B1). Examples of the polyolefin (B2) include polypropylene-based resins such as propylene homopolymers and propylene-α-olefin copolymers, polybutene resins, and cyclic olefin resins such as norbornene resins.

[0090] The thickness of the release agent layer is not particularly limited, and may be 5 μm or more and 70 μm or less in one embodiment. The thickness of the release agent layer is preferably 8 μm or more and 50 μm or less. The thickness of the release agent layer is measured, for example, by the method described in the examples below.

[0091] The content of the resin composition composed of the silylated polyolefin (A) and the polyolefin (B) other than the silylated polyolefin (A) may be 90% by mass or 100% by mass or less based on the total amount (100% by mass) of the release agent layer. The content of the resin composition is preferably 95% by mass or more, more preferably 97% by mass or more, and even more preferably 99% by mass or more.

[0092] The release agent layer may contain various additives such as antioxidants, ultraviolet absorbers, antistatic agents, surfactants, photoinitiators, and light stabilizers depending on the purpose, so long as the layered product can be easily peeled from the desired peeling direction while preventing unintended peeling of the layered product without impairing the anisotropy of the peeling force. For example, the content of the additives may be 0% by mass or more and 10% by mass or less based on the total amount (100% by mass) of the release agent layer. The content of the additives is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0093] In one aspect of the anisotropic release sheet according to the present embodiment, when a laminate is laminated on the release agent layer and the laminate is peeled off from the release agent layer, it is also preferable that the second release force in the second direction is larger than the first release force in the first direction in the peel force of the release agent layer against the laminate. The ratio of the second release force to the first release force (second release force / first release force) is preferably 1.1 times or more, more preferably 1.2 times or more, even more preferably 1.3 times or more, and even more preferably 1.5 times or more. The upper limit of the ratio of the second release force to the first release force is not particularly limited. The upper limit of the ratio of the second release force to the first release force may be, for example, 2.5 times or less, or 2.0 times or less. The ratio of the second release force to the first release force can be changed, for example, by adjusting the content of the silylated polyolefin (A) contained in the release agent layer within the above-mentioned range.

[0094] The anisotropic release sheet according to the present embodiment can be applied to general release sheet applications. The anisotropic release sheet according to the present embodiment can be used, for example, as a protective sheet for the adhesive layer, and as a process sheet used in the process of forming a sheet-like object on the release surface of the release agent layer of the release sheet. When the anisotropic release sheet according to the present embodiment is used as a process sheet, it can be used, for example, as a process sheet for producing various resin sheets, various composite materials, resin materials for electronic components, and synthetic leather. The anisotropic release sheet according to the present embodiment can be easily peeled from the desired direction of peeling even for laminates with low tackiness while suppressing unintended peeling, and is therefore useful, for example, as a process sheet for producing resin materials for electronic components such as flexible printed circuits. Examples of resin materials for electronic components such as flexible printed circuits include epoxy resins.

[0095] In one aspect of the anisotropic release sheet according to this embodiment, when the laminate is an adhesive sheet having an adhesive layer, the first peel force of the adhesive layer in the adhesive sheet relative to the release layer is preferably 100 mN / 25 mm or more and 1500 mN / 25 mm or less. The peel strength of the release agent layer from the pressure-sensitive adhesive sheet can be measured by the method described in the Examples below. In this specification, the pressure-sensitive adhesive sheet is a concept that includes pressure-sensitive adhesive tape.

[0096] Furthermore, in one aspect of the anisotropic release sheet according to the present embodiment, when the laminate is an epoxy resin used for electronic components, the first peel strength of the release agent layer against the epoxy resin is preferably 50 mN / 30 mm or more and 3000 mN / 30 mm or less.

[0097] The first peel strength of the release agent layer against the epoxy resin for electronic materials can be measured, for example, as follows. A coating solution containing an epoxy resin for electronic materials is applied to the release surface (first release agent layer surface) of the anisotropic release sheet so that the film thickness after drying is the desired film thickness, and then heated and dried to form a resin layer of the epoxy resin. The sheet is then left to stand for a predetermined time in a thermostatic chamber at 23°C and a relative humidity of 50%RH, and cut along the first direction to a width of 30 mm to obtain a test piece. Using a tensile tester, the resin layer of the epoxy resin is pulled along the first direction against the anisotropic release sheet at a peel speed of 1000 mm / min in the 180° direction, and the force at the time of peeling is measured and taken as the first peel strength. The second peel strength can also be measured in the same manner, except that the cutting direction and peeling direction are changed to the second direction.

[0098] [Manufacturing method of anisotropic release sheet] An example of a preferred method for producing the anisotropic release sheet according to this embodiment includes the following steps. Step (P1): A step of preparing a substrate. Step (P2): A step of preparing a resin composition composed of a silylated polyolefin (A) and a polyolefin (B) containing at least a polyethylene (B1) other than the silylated polyolefin (A), wherein, when the total of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100 mass%, the content of the silylated polyolefin (A) is 0.1 mass% or more and 3 mass% or less, and the content of the polyethylene (B1) is 90 mass% or more. Step (P3): A step of melt-extruding the resin composition melted at a temperature of 230° C. or higher and 330° C. or lower onto at least one surface of a substrate. The substrate is transported along a first direction, and the molten resin composition is laminated on the substrate being transported.

[0099] In the manufacturing method of the anisotropic release sheet according to this embodiment, the first direction is preferably the machine direction (MD) when manufacturing the anisotropic release sheet, and the second direction is preferably a direction perpendicular to the machine direction (TD) when manufacturing the anisotropic release sheet.

[0100] Step (P1) is a step of preparing a substrate for supporting the release agent layer. The substrate may be any of the above-mentioned substrates depending on the purpose. The substrate may be obtained by a known manufacturing method.

[0101] Step (P2) is a step of preparing a resin composition composed of a silylated polyolefin (A) and a polyolefin (B) other than the silylated polyolefin (A), which is used to form a release agent layer on the substrate prepared in step (P1). The resin composition may be the resin composition described above. The resin composition may be obtained by a known manufacturing method.

[0102] In step (P3), the resin composition prepared in step (P2) is melt-extruded onto a substrate transported along a first direction to provide a release agent layer. In step (P3), the temperature of the resin composition when melt-extruded onto the substrate is 230° C. or higher and 330° C. or lower. The temperature when the resin composition is melted and extruded (extrusion resin temperature) is the temperature when it is extruded from a die, and can be measured as the temperature of the resin composition in the die of the extruder. The temperature at which the resin composition is melted and extruded is preferably 240° C. or higher, and more preferably 250° C. or higher. The temperature at which the resin composition is melted and extruded is preferably 310° C. or lower, and more preferably 300° C. or lower.

[0103] The release agent layer is obtained as follows. First, the resin composition is charged into a hopper of an extruder equipped with a T-die, and the cylinder temperature and the die temperature are appropriately adjusted according to the composition of the resin composition. Next, the film-like melt kneaded product of the resin composition prepared in the above step (P2) is extruded from the T-die toward the substrate. At this time, the substrate is transported between the touch roll and the cooling roll. Then, the extruded film-like melt kneaded product is cooled by pressing it against the cooling roll by the touch roll. This allows the release agent layer to be formed on the substrate being transported.

[0104] The speed at which the substrate is conveyed is not particularly limited and may be, for example, 10 m / min or more and 300 m / min or less. The speed at which the substrate is conveyed is preferably 30 m / min or more and 200 m / min or less.

[0105] Through the above steps, the anisotropic release sheet according to this embodiment can be obtained.

[0106] Here, an example of the manufacturing method of the anisotropic release sheet according to the present embodiment will be described with reference to the drawings. In the drawings, some parts are illustrated enlarged or reduced in size to facilitate explanation. Referring to FIG. 3, FIG. 3 shows a schematic diagram of a main part of a process in which a molten resin composition is melt-extruded onto a substrate 10 unwound from a roll-shaped substrate 10A using a laminating device 200 to provide a release agent layer 30 on the substrate 10.

[0107] The laminating apparatus 200 includes an extruder 202 equipped with a T-die 204, a cooling roll 208, a touch roll 206 adjacent to the cooling roll 208 at an interval, a payout roll 210, and a take-up roll 212. The roll-shaped substrate 10A is wound up so that the surface on which the release agent layer 30 is to be provided faces the core side, and the opposite surface faces the outer circumferential surface.

[0108] The substrate 10 is unwound from the roll-shaped substrate 10A by the unwinding roll 210. The unwound substrate 10 passes through a guide roll (not shown) and reaches the gap between the cooling roll 208 and the touch roll 206. The substrate 10 is transported along the direction toward the X direction, which is the first direction. After the substrate 10 reaches the gap between the cooling roll 208 and the touch roll 206, the molten resin composition is extruded from the T die 204 toward the substrate 10 in the form of a film. The temperature of the resin composition when extruded from the T die 204 is 230°C or higher and 330°C or lower. The resin composition extruded in the form of a film comes into contact with the substrate 10 in the gap between the cooling roll 208 and the touch roll 206. The resin composition extruded in the form of a film is then pressed against the cooling roll 208 by the touch roll 206 in the gap between the cooling roll 208 and the touch roll 206, whereby the resin composition supplied in the form of a film is pressed onto the substrate 10. This forms an anisotropic release sheet 100 in which the release agent layer 30 is laminated on the substrate 10. The anisotropic release sheet 100 in which the release agent layer 30 is laminated on the substrate 10 passes through a guide roll (not shown) and is taken up by a take-up roll 212 to form a roll-shaped anisotropic release sheet 100A. The roll-shaped anisotropic release sheet 100A is taken up so that the substrate 10 is on the core side and the release agent layer 30 is on the outer peripheral surface side.

[0109] The winding speed of the anisotropic release sheet 100 is preferably within the range of the speed at which the base material is transported described above. The gap between the cooling roll 208 and the touch roll 206 can be adjusted, for example, so that the release agent layer 30 has a predetermined thickness.

[0110] An example of the manufacturing method of the anisotropic release sheet according to the present embodiment has been described above with reference to the drawings, but the manufacturing method of the anisotropic release sheet according to the present embodiment is not limited thereto. For example, in FIG. 3, the roll-shaped substrate 10A may be wound up so that the surface on which the release agent layer 30 is to be provided is the outer peripheral surface side and the opposite surface is the core side. The roll-shaped anisotropic release sheet 100A may be wound up so that the substrate 10 is on the outer peripheral surface side and the release agent layer 30 is on the core side. The manufacturing method of the anisotropic release sheet according to the present embodiment may adopt various forms as long as it can exhibit anisotropy of the release force.

[0111] The present invention is not limited to the above-described embodiment, and may include modifications and improvements within the scope of the present invention. EXAMPLES

[0112] Examples will be described below, but the present invention is not limited to these examples in any way.

[0113] [Example 1] As the base material, high-quality paper (manufactured by Nippon Paper Industries Co., Ltd., basis weight 64 g / m 2 ) was prepared. As the silylated polyolefin (A), a dilution product (manufactured by Mitsui Chemicals, Inc., product name "EXFORA (registered trademark) polyethylene masterbatch") in which a polyethylene-silicone-polyethylene triblock copolymer was diluted with low-density polyethylene was prepared. The silylated polyolefin (A) is a polyethylene-silicone-polyethylene triblock copolymer. In Tables 1 and 2, the silylated polyolefin (A) is represented as "SiPO". As the polyethylene (B1) in the polyolefin (B), a low-density polyethylene ("Sumikasen L405" manufactured by Sumitomo Chemical Co., Ltd., MFR: 3.7 g / 10 min, density: 0.924 g / cm 3 ) was prepared. The polyethylene (B1) is represented as "PE-1" in Tables 1 and 2.

[0114] When the total of the silylated polyolefin (A) and the polyethylene (B1) is taken as 100% by mass, 1.67 parts by mass of the polyethylene master batch of the silylated polyolefin (A) prepared above and 98.33 parts by mass of the polyethylene (B1) were mixed in a dry state so that the content of the silylated polyolefin (A) was 0.5% by mass, to prepare a resin composition for forming a release agent layer. The prepared resin composition was heated and melted, and the melted resin composition was extruded from a T-die at an extrusion resin temperature of 280 ° C. to form a release agent layer having a thickness of 20 μm on one side of the substrate being conveyed. In this way, an anisotropic release sheet of Example 1 having a release agent layer laminated directly in contact with the substrate was obtained.

[0115] The thickness of the release agent layer was controlled by adjusting the back pressure of the extruder screw. Cooling water adjusted to 23°C was passed through a water-cooled roll, and the resin composition for forming the release agent layer on the substrate was brought into contact with the surface of the water-cooled roll, thereby cooling and solidifying the molten resin composition for forming the release agent layer. The conveying speed of the substrate when the resin composition for forming the release agent layer was laminated was 50 m / min.

[0116] [Examples 2 to 5] Except for changing the formulation of the resin composition according to Table 1, the anisotropic release sheet of each example was obtained in the same manner as in Example 1.

[0117] [Comparative Example 1 and Comparative Example 2] Release sheets of Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the formulation of the resin composition was changed according to Table 2.

[0118] [Comparative Example 3] Except for not using the silylated polyolefin (A), a release sheet of Comparative Example 3 was obtained in the same manner as in Example 1. The release agent layer in the release sheet of Comparative Example 3 was a laminate layer of polyethylene.

[0119] [Comparative Example 4] The release sheet obtained in Comparative Example 3 was used, and the laminate layer of polyethylene was used as a filling layer. A release agent composition prepared by diluting a solvent-addition type silicone release agent (KS-847, manufactured by Shin-Etsu Chemical Co., Ltd.) and a curing catalyst (CAT-PL-50T, manufactured by Shin-Etsu Chemical Co., Ltd.) in toluene was applied to the surface of this filling layer using an applicator in an amount of 0.5 g / m2 in terms of weight after drying. 2 A release agent layer was provided by applying the coating solution to the substrate and drying by heating so that the coating solution had a viscosity of 100%. In this manner, a release sheet of Comparative Example 4 was obtained. In Table 2, the solvent addition type silicone release agent is indicated as "Si".

[0120] [Comparative Example 5] A release sheet of Comparative Example 5 was obtained in the same manner as in Comparative Example 4, except that the release agent composition containing the solvent-addition type silicone release agent was replaced with a release agent composition prepared by diluting a silicone-modified alkyd resin (manufactured by Resonac Corporation, product name "Tesfine 319") in a mixed solvent of toluene and methyl ethyl ketone. In Table 2, the silicone-modified alkyd resin is represented as "Si-ALK".

[0121] <Measurement of release agent layer thickness> The measurements were taken at 23° C. using a constant pressure thickness gauge (manufactured by Techclock Corporation, model number: "PG-02J", standard specifications: compliant with JIS K6783-1994, JIS Z1702-1994, and JIS Z1709-1995).

[0122] <Peel force measurement> The peel strength was measured in both MD as a first direction and TD as a second direction.

[0123] (Peeling force (A)) First, a polyester adhesive tape (manufactured by Nitto Denko Corporation, No. 31B, polyester base material, acrylic adhesive) was attached to the release agent layer of the release sheet obtained in each example to prepare a sample for measuring peel strength. Next, the sample for measuring peel strength was cut to a dimension of 150 mm in length (MD direction) × 25 mm in width (TD direction) to obtain a first sample for measuring peel strength, and cut to a dimension of 150 mm in length (TD direction) × 25 mm in width (MD direction) to obtain a second sample for measuring peel strength. After that, the first sample for measuring peel strength and the second sample for measuring peel strength were left for 30 minutes under conditions of a temperature of 23 ° C. and a relative humidity of 50%, and then a 180 ° peel test (a test method in which a polyester adhesive tape is peeled off at 180 ° from a sample for measuring peel strength) was performed in accordance with JIS Z0237:2022 at a peel speed of 0.3 m / min, and the first and second peel strengths were measured. The results are shown in the column of peel strength (A) in Tables 1 and 2.

[0124] (Peeling force (E)) First, an adhesive tape (polyester substrate, epoxy thermosetting adhesive) was attached to the release agent layer of the release sheet obtained in each example to prepare a sample for measuring peel strength. Next, the sample for measuring peel strength was cut to a dimension of 150 mm in length (MD direction) × 30 mm in width (TD direction) to obtain a first sample for measuring peel strength, and cut to a dimension of 150 mm in length (TD direction) × 30 mm in width (MD direction) to obtain a second sample for measuring peel strength. After that, the first sample for measuring peel strength and the second sample for measuring peel strength were left for 30 minutes under conditions of a temperature of 23 ° C. and a relative humidity of 50%, and then a 180 ° peel test (a test method in which an adhesive tape is peeled off at 180 ° from a sample for measuring peel strength) was performed in accordance with JIS Z0237:2022 at a peel speed of 0.3 m / min, and the first and second peel strengths were measured. The results are shown in the column of peel strength (E) in Tables 1 and 2.

[0125] [Table 1]

[0126] [Table 2]

[0127] The release sheet of Comparative Example 3 exhibits anisotropy in the release force, but since the release force is too high, it does not have an appropriate release force, and the laminate is difficult to peel from the desired direction. The release sheets of Comparative Examples 1 and 2 have a content of silylated polyolefin (A) in the release agent layer exceeding 3 mass %, and the first release force and the second release force are the same, so they do not exhibit anisotropy in the release force. The release sheets of Comparative Examples 4 and 5 have a release agent layer formed by applying a release agent composition onto a polyethylene sealing layer, and since the first release force and the second release force are the same, they do not exhibit anisotropy in the release force.

[0128] On the other hand, from the results of each example, it can be seen that when a resin composition for forming a release agent layer is used in which the content of silylated polyolefin (A) is 0.1 mass% or more and 3 mass% or less and the content of polyethylene (B1) is 90 mass% or more, when the sum of the silylated polyolefin (A) and the polyethylene (B1) as polyolefin (B) is taken as 100 mass%, an anisotropic release sheet having a release agent layer formed from the resin composition exhibits anisotropy in release force and has an appropriate release force.

[0129] From the above results, with the anisotropic release sheet of this embodiment, when peeling off a laminate layered on the release surface of the release sheet, unintended peeling of the laminate is suppressed, while the laminate can be easily peeled off from the desired direction. [Explanation of symbols]

[0130] 10, 10A...substrate, 11...first substrate surface, 12...second substrate surface, 30...release agent layer, 31...first release agent layer surface, 32...second release agent layer surface, 100, 100A,...anisotropic release sheet, 200...laminating device, 202...extruder, 204...T-die, 206...touch roll, 208...cooling roll, 210...delivery roll, 212...take-up roll.

Claims

1. An anisotropic release sheet having a first direction and a second direction perpendicular to the first direction, A substrate and a release agent layer provided on at least one surface of the substrate, the release agent layer comprises a resin composition composed of a silylated polyolefin (A) and a polyolefin (B) other than the silylated polyolefin (A), The polyolefin (B) contains at least polyethylene (B1), When the total amount of the silylated polyolefin (A) and the polyolefin (B) in the release agent layer is taken as 100 mass%, the content of the silylated polyolefin (A) is 0.1 mass% or more and 3 mass% or less, and the content of the polyethylene (B1) is 90 mass% or more, An anisotropic release sheet in which, when a laminate is laminated on the release agent layer and the laminate is peeled from the release agent layer, the peel force of the release agent layer with respect to the laminate is different between a first peel force in the first direction and a second peel force in the second direction.

2. The anisotropic release sheet according to claim 1, The ratio of the second peel force to the first peel force is 1.1 or more. Anisotropic release sheet.

3. The anisotropic release sheet according to claim 1 or 2, the silylated polyolefin (A) is a copolymer having a structural unit (a1) derived from a hydrosilane compound and a structural unit (a2) derived from a terminal double bond-containing polyolefin, The structural unit (a1) includes one or more structural units represented by the following general formula (1): Anisotropic release sheet. 【Chemistry 1】 (In the general formula (1), R １ is a hydrocarbon group or a silicon-containing group, Y １ is an oxygen atom, a sulfur atom, or NR １１ is a group represented by N.R. １１ In the group represented by the formula: N is a nitrogen atom, and R １１ is a hydrogen atom or a hydrocarbon group, R １ When there are multiple R １ are the same or different from each other, R １１ When there are multiple R １１ are the same or different from each other, Y １ If there are multiple Y １ are the same or different from each other.)

4. The anisotropic release sheet according to claim 1 or 2, The silylated polyolefin (A) is a block copolymer. Anisotropic release sheet.

5. The anisotropic release sheet according to claim 1 or 2, The resin composition is composed only of the silylated polyolefin (A) and the polyethylene (B1). Anisotropic release sheet.

6. The anisotropic release sheet according to claim 1 or 2, The thickness of the release agent layer is 8 μm or more and 50 μm or less. Anisotropic release sheet.

7. The anisotropic release sheet according to claim 1 or 2, The substrate is one or two of a paper substrate and a resin substrate; Anisotropic release sheet.

8. A method for producing the anisotropic release sheet according to claim 1 or 2, comprising the steps of: providing the substrate; preparing the resin composition; A step of melt-extruding the resin composition molten at a temperature of 230° C. or more and 330° C. or less onto at least one surface of the substrate; having The substrate is transported along the first direction, The resin composition is laminated onto the substrate being transported. A method for producing an anisotropic release sheet.

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