Sheet for the Easy Peel layer

Abstract

The present invention provides a sheet for easily peelable layers, the sheet being a stretched sheet that contains a polypropylene resin as a component (A) and an inorganic filler as a component (B).

Description

Technical Field

[0001] The present invention relates to a sheet for an easy peel layer.

Background Art

[0002] For improving the design, it is generally practiced to paint plastics or attach decorative films. However, when recycling the plastic molded body, it is necessary to remove the coating film and the film. For example, Patent Document 1 proposes a method of cutting a resin molded body having a coating film formed on the surface, and mixing and stirring these together with a metal sphere and water to peel off the coating film. In addition, Patent Document 2 proposes a method of forcibly peeling off a coating film from a plastic molded body using high-pressure jet water or the like. Further, Patent Document 3 discloses a laminated film having easy peelability utilizing interfacial peeling between a filler-filled layer and another layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the method described in Patent Document 1, the molded body is cut and water and metal are mixed and stirred, making it difficult to separate the resin from the coating and remove metal particles. In the method described in Patent Document 2, high-pressure fluid is used, making separation and collection difficult. Easy-peel properties can be achieved by utilizing interfacial delamination, as described in Patent Document 3, or by utilizing material fracture of the layer itself. However, when interfacial delamination is used as in Patent Document 3, stable peel strength cannot be obtained, and the coating or decorative surface of the molded body may peel off during use, rendering it unusable. On the other hand, easy-peel properties that utilize material fracture can exhibit stable peel strength, resulting in high user satisfaction. Conventionally, an easy-peel layer that causes material fracture is known to be composed of a polymer having a sea-island structure. The inventors focused on the fact that if such an easy-peel layer could be constructed from a material with a low environmental impact, optimal recycling would be possible. In view of these circumstances, the object of the present invention is to provide a material for an easy-peel layer with a low environmental impact. [Means for solving the problem]

[0005] The inventors have found that the above problem can be solved by a stretched sheet containing a polypropylene resin and an inorganic filler. In other words, the above problem is solved by the present invention as described below. Appearance 1 A stretched sheet comprising a polypropylene resin as component (A) and an inorganic filler as component (B), the sheet being for use as an easy-peel layer. Appearance 2 The sheet according to embodiment 1, wherein the weight ratio of component (B) / [component (A) + component (B)] is 3 to 60% by weight. Appearance 3 The aforementioned component (A) is a polypropylene resin consisting of component (A1) and an optional component (A2). The aforementioned component (A1) is a propylene (co)polymer containing 0 to 10% by weight of comonomer-derived units selected from C2 to C10-α-olefins (excluding C3-α-olefins), 100 to 50% by weight. Component (A2) is an ethylene-α-olefin copolymer containing more than 10% by weight and up to 90% by weight of ethylene-derived units, and is 0-50% by weight. The MFR (at 230°C and 2.16 kg load) of component (A) is 1 to 15 g / 10 minutes. The sheet described in embodiment 1 or 2. Pattern 4 The sheet according to any one of embodiments 1 to 3, wherein the component (B) is selected from the group consisting of plate-shaped inorganic fillers, granular inorganic fillers, and combinations thereof. Appearance 5 The sheet according to embodiment 4, wherein the component (B) is selected from the group consisting of talc, mica, calcium carbonate, and combinations thereof. Appearance 6 The sheet according to embodiment 5, wherein the component (B) is talc. Appearance 7 The sheet according to claim 5, wherein the component (B) is calcium carbonate. Appearance 8 A product comprising a sheet according to any one of embodiments 1 to 7 as an easy-peel layer. [Effects of the Invention]

[0006] This invention provides a material for easy-peel layers that has a low environmental impact. [Brief explanation of the drawing]

[0007] [Figure 1] This is a conceptual diagram showing the peeling process of a multilayer sheet with an easy-peel layer. [Figure 2] This is a diagram illustrating the overview of a polypropylene multilayer sheet. [Figure 3] This is a diagram illustrating one method for manufacturing a polypropylene multilayer sheet. [Figure 4] This diagram illustrates another embodiment of the manufacturing method for polypropylene multilayer sheets. [Figure 5] This is a micrograph showing the peeling condition of the multilayer sheet obtained in the example. [Figure 6]It is a schematic diagram showing the peeling state of the multilayer sheet obtained in the example.

Mode for Carrying Out the Invention

[0008] Unless otherwise specified, in this disclosure, "X to Y" includes its end values, that is, X and Y. Sheets and films are used synonymously. In particular, a film-like member with a thickness of 150 μm or more may be referred to as a sheet, and a film-like member with a thickness of less than 150 μm may be referred to as a film. Also, sheets and films may be collectively referred to as "sheet-like members".

[0009] 1. Sheet for easy peel layer The sheet for the easy peel layer is a stretched sheet containing a polypropylene-based resin as component (A) and an inorganic filler as component (B). The stretching may be uniaxial stretching or multiaxial stretching, but considering the balance between ease of production and easy peelability, biaxial stretching is preferred.

[0010] (1) Component (A): Polypropylene-based resin The polypropylene-based resin is a resin having polypropylene as the main component. The polypropylene-based resin constituting the sheet for the easy peel layer preferably consists of 100 to 50% by weight of component (A1) and 0 to 50% by weight of optional component (A2). When the content of component (A2) exceeds 0% by weight, component (A) may be a so-called heterophase copolymer (HECO) obtained by polymerizing component (A1) and polymerizing component (A2) in the presence of the said component, or it may be a blend of separately polymerized and prepared component (A1) and component (A2). From the viewpoint of obtaining component (A) with fewer manufacturing steps, component (A) is preferably HECO. The said polypropylene-based resin is different from so-called modified polypropylene.

[0011] Component (A1) is a propylene (co)polymer containing 0 to 10% by weight of comonomer-derived units selected from C2 to C10 α-olefins (excluding C3 α-olefins). The comonomer selected from C2 to C10 α-olefins naturally does not contain C3 α-olefins. When a comonomer is included, ethylene is preferred from an economic standpoint. If the amount of comonomer-derived units exceeds the upper limit, the rigidity of the sheet may decrease, or it may become difficult to manufacture the polypropylene resin. From this viewpoint, it is preferable that component (A1) contains 0 to 1% by weight of comonomer-derived units, and more preferably that it does not contain comonomer-derived units, i.e., that it is a propylene homopolymer. Alternatively, if component (A1) contains comonomer-derived units, it is preferable that the amount is greater than 0% by weight and 0.5% by weight or less.

[0012] The content of component (A1) in the polypropylene resin is 50 to 100% by weight. If the content of component (A1) is low, the rigidity of the sheet may decrease, or it may become difficult to manufacture the polypropylene resin. Therefore, the content of component (A1) is preferably 60 to 100% by weight. The content of component (A2) is 0 to 50% by weight, preferably 0 to 40% by weight.

[0013] The optional component (A2) is an ethylene-α-olefin copolymer containing ethylene-derived units in an amount exceeding 10% by weight and not exceeding 90% by weight. If the amount of ethylene-derived units is below the lower limit or above the upper limit, the cold shock resistance decreases. From this viewpoint, the content of ethylene-derived units is preferably 15 to 85% by weight, and more preferably 20 to 80% by weight. The α-olefin is not limited to ethylene, but is preferably propylene, 1-butene, 1-hexene, or 1-octene, more preferably propylene or 1-butene, and even more preferably propylene.

[0014] Furthermore, component (A) may be a propylene homopolymer (HOMO) or propylene random copolymer (RACO) containing 0 to 10% by weight of comonomer-derived units selected from C2-C10α-olefins (excluding C3α-olefins). These embodiments correspond to the case where the content of component (A1) is 100% by weight.

[0015] The total ethylene content of component (A) and the ethylene-derived unit content of component (A1) are measured by known methods, but preferred measurement methods are described below. For copolymer samples dissolved in a mixed solvent containing 1,2,4-trichlorobenzene and deuterated benzene, a Bruker AVANCE III HD400 was used. 13 Using a C resonance frequency of 100 MHz, under the following conditions: measurement temperature 120°C, flip angle 45 degrees, pulse interval 7 seconds, sample rotation speed 20 Hz, and number of integrations 6000 times. 13 Obtain a 1C-NMR spectrum. The mixed solvent is preferably 1,2,4-trichlorobenzene / deuterated benzene / hexamethyldisiloxane = 30 / 10 / 1 (by volume). Using the spectrum obtained above, the total ethylene content (weight %) of component (A) is determined by the method described in the literature Kakugo, Y. Naito, K. Mizunuma and T. Miyatake, Macromolecules, 15, 1150-1152 (1982). When component (A1) is measured as a sample, the total ethylene content (weight %) obtained by the above method is the ethylene unit content (weight %) of component (A1). Furthermore, if component (A1) contains comonomer-derived units other than ethylene, the content of those comonomer units is determined in the same way as the content of ethylene-derived units.

[0016] The ethylene unit content in component (A2) can also be measured by known methods, but a preferred measurement method is described below. Except for using the integral intensity T'ββ obtained by the following formula instead of the integral intensity Tββ obtained when measuring the total ethylene content of component (A) using the method described in the above-mentioned literature, the calculation is performed in the same way as for the total ethylene content to determine the ethylene unit content (weight %) of component (A2). T'ββ=0.98×Sαγ×A' / (1-0.98×A') Here, A' = Sαγ / (Sαγ+Sαδ), and Sαγ and Sαδ are as described in the above-mentioned literature. It is calculated from this.

[0017] In a component (A) consisting of component (A1) and component (A2), if component (A1) contains ethylene units, the ethylene-derived unit content in component (A2) can be determined by the following formula, provided that the weight ratio (component (A2) / [component (A1) + component (A2)]) is clear from the polymerization conditions. Ethylene-derived unit content of component (A2) (unit: weight %) = [Total ethylene content of component (A) - Ethylene-derived unit content of component (A1) × Percentage of component (A1) in component (A)] / (Percentage of component (A2) in component (A))

[0018] The weight ratio of component (A2) / [component (A1)+component (A2)] can be calculated using the following formula. Component (A2) / [Component (A1) + Component (A2)] (Unit: weight %) = Total ethylene content of Component (A) / (Ethylene unit content in Component (A2) / 100)

[0019] The MFR (at 230°C and with a load of 2.16 kg) of component (A) is preferably 1 to 15 g / 10 min. If the MFR exceeds the upper limit, it becomes difficult to stably stretch the sheet for the easy-peel layer. Conversely, if the MFR is below the lower limit, it becomes difficult to easily stretch the sheet for the easy-peel layer. From this viewpoint, the lower limit of the MFR is preferably 2 g / 10 min or more, more preferably 3 g / 10 min or more, and the upper limit is preferably 10 g / 10 min or less, more preferably 8 g / 10 min or less. The MFR is measured in accordance with JIS K7210-1 and based on JIS K6921-2 under conditions of a temperature of 230°C and a load of 2.16 kg.

[0020] (2) Component (B): Inorganic filler Examples of inorganic fillers from a material standpoint include the following: Natural silicic acids or silicates such as talc, kaolinite, clay, birophyllite, serinite, wollastonite, and mica; synthetic silicic acids or silicates such as calcium silicate, aluminum silicate, silicic acid, and anhydrous silicic acid; calcium carbonates such as precipitated calcium carbonate and heavy calcium carbonate, or carbonates such as magnesium carbonate; hydroxides such as aluminum hydroxide and magnesium hydroxide; oxides such as zinc oxide and magnesium oxide.

[0021] Furthermore, examples of inorganic fillers from a shape perspective include the following: Powdered fillers such as calcium silicate, aluminum silicate, silicic acid, anhydrous silicic acid, and other synthetic silicic acids or silicates; plate-like fillers such as talc, kaolinite, clay, and mica; whisker-like fillers such as basic magnesium sulfate whiskers, calcium titanate whiskers, aluminum borate whiskers, sepiolite, PMF (Processed Mineral Filler), xonotlite, potassium titanate, and elestadite; balloon-like fillers such as glass balloons and fly ash balloons; and fibrous fillers such as glass fiber.

[0022] One type of inorganic filler may be used, or two or more types may be used in combination. To improve the dispersibility of these fillers, surface treatment of the inorganic fillers may be performed as necessary. The inorganic filler is not limited, but from the viewpoint of improving dispersibility in the sheet for the easy-peel layer, plate-shaped inorganic fillers or granular inorganic fillers are preferred. As plate-shaped inorganic fillers, known ones such as talc, kaolinite, clay, and mica can be used, but talc and mica are preferred. Talc is particularly preferred because its main surface is oriented in the stretching direction and it can exhibit easy-peel properties with a low concentration of additive. Calcium carbonate is preferred as a granular inorganic filler. The volume-average particle diameter of the inorganic filler is preferably 1 to 10 μm, more preferably 2 to 7 μm. If the volume-average particle diameter is less than the lower limit, the easy-peel properties may not be sufficient. If the volume-average particle diameter exceeds the upper limit, breakage is more likely to occur during stretching, making it difficult to prepare the stretched sheet-like member that will be used as the raw material for the sheet for the easy-peel layer. The aforementioned volume-average particle diameter can be measured as the 50% diameter in the cumulative fraction based on volume by laser diffraction (based on JIS R1629).

[0023] (3) Composition ratio The weight ratio of components (A) and (B) in the sheet for the easy-peel layer is preferably as follows: Component (B) / [Component (A)+Component (B)]=3~60% by weight If the amount of component (B) is too small, the easy-peel properties will not be sufficient, and if the amount of component (B) is too large, it may become difficult to manufacture the sheet for the easy-peel layer, or the adhesion with other layers may decrease. From this viewpoint, the lower limit of the weight ratio is preferably 5% by weight or more, and more preferably 7% by weight or more. The upper limit is preferably 50% by weight or less, and more preferably 40% by weight or less.

[0024] (4) Additives The sheet for the easy-peel layer may be composed of a resin composition containing a nucleating agent, or it may be composed of a resin composition or polymer without a nucleating agent. A nucleating agent is an additive used to increase rigidity by increasing the crystalline components in the resin. Known additives can be used for this purpose. From an economic standpoint, the amount of nucleating agent is preferably 1 part by weight or less per 100 parts by weight of polymer.

[0025] The resin composition constituting the sheet for the easy-peel layer may contain conventional additives commonly used in polyolefins, such as antioxidants, chlorine absorbers, heat stabilizers, light stabilizers, ultraviolet absorbers, internal lubricants, external lubricants, antiblocking agents, antistatic agents, antifogging agents, flame retardants, dispersants, copper pollution inhibitors, neutralizing agents, plasticizers, crosslinking agents, peroxides, oil spreaders, and other organic and inorganic pigments, to the extent that they do not impair the easy-peel properties. The amount of each additive may be a known amount. Furthermore, synthetic resins other than the polypropylene resin (e.g., modified polypropylene) or synthetic rubber may be contained, to the extent that they do not impair the effects of the present invention. The synthetic resin or synthetic rubber may be one type or two or more types.

[0026] (5) Mechanism The sheet for the easy-peel layer possesses excellent easy-peel properties. While the reasons for this are not limited, it can be inferred as follows: Because the sheet for the easy-peel layer is stretched, the inorganic filler, which is component (B), is arranged and dispersed within component (A). The bond strength at the interface between component (B) and component (A) is lower than the fracture strength of component (A) itself, and also lower than the bond strength at the interfaces of each layer, because it is a bond between organic and inorganic materials. Therefore, when an external force is applied to peel off a layer on top of the easy-peel layer, cracks preferentially occur at the interface between component (B) and component (A) of the easy-peel layer. These cracks then chain together to the arranged and dispersed component (B). As a result, it is thought that easy-peel properties are exhibited. Figure 1 is a schematic diagram illustrating the peeling state of a multilayer sheet. An adhesive layer 15 and a top layer 20 are laminated on top of the easy-peel layer 10, and another layer 30 is laminated below the easy-peel layer 10. As shown in Figure 1, when the top layer 20 is peeled off, material fracture occurs in the easy-peel layer 10 due to the aforementioned action. As a result, the top layer 20 can be easily removed. The sheet for the easy-peel layer may be uniaxially oriented or multiaxially oriented.

[0027] The peeling strength provided by the Easy Peel Layer sheet is not limited as it varies depending on the structure of the laminate incorporating it. However, from the viewpoint of balancing high adhesion and high peelability, in one embodiment it is preferably 3 to 200 N / 15 mm, more preferably 6 to 100 N / 15 mm, and even more preferably 8 to 50 N / 15 mm. The peeling strength is determined by a 180-degree peel test using a strip-shaped test piece with a width of 15 mm. In one embodiment, the distance between the grips is 50 mm, the movement speed of the grips is 300 mm / min, the tensile length is 100 mm, and the average value of the test force in the stable section of 50 mm during material fracture is used as the test value.

[0028] The peeling strength is preferably measured by the following method. The test will be conducted using a 180-degree peel test. A multilayer sheet will be cut into strips 15 mm wide to form test specimens. The top layer and bottom layer will be clamped in grips, with a distance of 50 mm between the grips. A tensile test will be performed by moving the grips at a speed of 300 mm / min. The peeling strength will be defined as the average test force over a stable 50 mm section during material fracture, after being pulled for 100 mm or more. As the testing apparatus, for example, an Autocom universal testing machine manufactured by TSE Corporation can be used.

[0029] (6)Applications The easy-peel layer sheet is useful as a layer that can exhibit easy-peel properties in various products. Its thickness and size are adjusted as appropriate depending on the application. If the layer composed of the easy-peel layer sheet is too thin, the easy-peel properties will not be stable, and if it is too thick, the peelability may decrease. From this viewpoint, in one embodiment, the thickness of the easy-peel layer sheet is 10 to 1000 μm. The lower limit is preferably 20 μm or more, more preferably 30 μm or more. The upper limit is preferably 300 μm or less, more preferably 200 μm or less.

[0030] 2. Products As mentioned above, the easy-peel layer sheet can be used in a variety of products. Examples of products include extruded articles, injection-molded articles, and vacuum-formed articles such as sheets. Examples of extruded articles include polypropylene multilayer sheets, and examples of vacuum-formed articles include food containers. In particular, the easy-peel layer sheet is useful as a layer that can exhibit easy-peel properties in polypropylene multilayer sheets, so the following explanation will use this product as an example.

[0031] (1) Thickness The thickness of the polypropylene multilayer sheet (hereinafter also simply referred to as "multilayer sheet") is preferably 0.1 to 5 mm. If the sheet is excessively thin, its easy-peel properties will decrease, making recycling difficult. If the sheet is excessively thick, manufacturing may become difficult. The lower limit is preferably 0.5 mm or more, more preferably 1.0 mm or more. The upper limit is preferably 5.0 mm or less, more preferably 4.0 mm or less, and even more preferably 3.5 mm or less. The thickness of the multilayer sheet is adjusted as appropriate depending on the application.

[0032] (2)Multilayer structure The multilayer sheet has a multilayer structure in which biaxially oriented polypropylene layers F and biaxially oriented polypropylene layers N are alternately laminated. Hereinafter, the biaxially oriented polypropylene layer F will also be called the "filler layer F," and the biaxially oriented polypropylene layer N will also be called the "neat layer N." Since the layers are fused together, the multilayer sheet is a single, integrated sheet. Whether the layers of the sheet are fused together and integrated can be confirmed by cross-sectional observation with a polarizing microscope, as described in International Publication No. 2020 / 075755. At least one of the filler layers F is composed of the sheet for the easy-peel layer. The layer composed of the sheet for the easy-peel layer is called "layer FE" or "filler layer FE."

[0033] As described later, in the multilayer sheet, the filler layer F is derived from a biaxially oriented polypropylene sheet-like member for that layer, and the neat layer N is derived from a biaxially oriented polypropylene sheet-like member for that layer. Each layer may be independently composed of the sheet-like member. This embodiment is shown in Figure 2(A). In the figure, 1' is a precursor described later, 20 is the top layer, F is the filler layer F, FE is layer FE, N is the neat layer N, and 1 is the multilayer sheet. The layers of the precursor 1' are fused together to form the multilayer sheet 1. In this embodiment, the neat layer N between the top layer 20 and layer FE also functions as an adhesive layer. In another embodiment, an adhesive layer may be provided between the top layer 20 and layer FE using a known adhesive. Alternatively, an adhesive layer may not be provided.

[0034] At least a portion of the entire layer may consist of a co-extruded layer in which filler layers F and neat layers N obtained by co-extrusion molding are alternately laminated. This embodiment is shown in Figure 2(B). In the figure, C represents a co-extruded layer, and for example, C[F / N] is a co-extruded layer having two layers: a filler layer F and a neat layer N. A multilayer sheet 1 is formed from a precursor 1' containing C[N / FE / N], C[F / N], and C[N / F / N].

[0035] The total number of layers in a multilayer sheet, excluding the top layer, is approximately 3 to 100. When the total number of layers is within this range, the multilayer sheet exhibits excellent moldability when formed into a molded body, i.e., it has excellent moldability. The number of layers depends on the thickness of each layer, but in one embodiment, it is preferable that there are a total of approximately 15 to 100 layers of filler layers F and neat layers N, each about 0.01 to 0.3 mm thick.

[0036] In the embodiment shown in Figure 2(B), the total number of layers in the multilayer sheet, excluding the top layer, is 8. In the embodiment including a co-extruded layer, the thickness of the co-extruded layer is preferably 0.02 to 0.50 mm. The total number of layers in the co-extruded layer is preferably 2 to 6, more preferably 2 to 5, even more preferably 2 to 4, and particularly preferably 2 to 3. The thickness of the co-extruded layer refers to the total thickness of C (represented as t in Figure 2(B)). In the case of Figure 2(B), the total number of co-extruded layers is 4.

[0037] Regarding the ratio DF / DN, which is the total thickness DF of the filler layer F to the total thickness DN of the neat layer N, if the value is too small, the rigidity of the multilayer sheet will be insufficient, and if the value is too large, the interlayer bonding of the multilayer sheet will be insufficient. From the balance between bonding and rigidity, the ratio is preferably 1 to 30, more preferably 1 to 25, and even more preferably 4 to 15. The thickness of each layer may be the same or different. The thickness of each layer is appropriately adjusted so that the ratio falls within the aforementioned range. The thickness of one filler layer F is preferably 20 μm to 300 μm. The thickness of one neat layer N is preferably 5 μm to 200 μm.

[0038] The melting point TmF of the filler layer F and the melting point TmN of the neat layer N satisfy the relationship TmF > TmN. TmF-TmN is not limited, but is preferably 1°C or higher, more preferably 10°C or higher, and even more preferably 25°C or higher. Furthermore, TmF-TmN is preferably 60°C or lower. If these melting points are excessively low, the rigidity and heat resistance of the multilayer sheet will be insufficient. From this viewpoint, TmF is preferably 160°C or higher, more preferably 165°C or higher, and TmN is preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 130°C or higher. These melting points are obtained by measuring them using DSC under conditions of heating from 30°C to 230°C at a heating rate of 10°C / min.

[0039] 1) Filler layer F The filler layer F, which is not layer FE, may be formed from any polymer and inorganic filler. In one embodiment, the filler layer that is not the easy-peel layer is composed of the aforementioned components (A) and (B), where the weight ratio of component (B) can be 0.5 to 60% by weight.

[0040] The layer FE is preferably located near the surface. In one embodiment, the layer FE is preferably located at a position 0.6 to 30% from the surface in the thickness direction. The position of the filler layer FE is defined by r / R. r is the position of the interface between the layer FE and other layers on the origin side in the thickness direction, with the surface of the multilayer sheet as the origin. Although there are two surfaces of the multilayer sheet, the origin is defined as the surface with the minimum r. R is the total thickness of the multilayer sheet. That is, it is preferable that 0.6% ≤ r / R ≤ 30%.

[0041] When multiple filler layers FE exist, the location of the layer in which easy peeling occurs can be determined by controlling the thickness of each layer FE and the content of the inorganic filler. Alternatively, the location can be determined by establishing a starting point in a specific layer, as in a peeling test. For example, if a starting point is established in a filler layer FE, that layer FE will undergo material fracture and easy peeling will occur. Similarly, if a starting point is established in layer N, the layer FE adjacent to that layer N will undergo material fracture and easy peeling will occur. If layers FE exist on both sides of layer N where a starting point is established, one of the layers FE will undergo material fracture and easy peeling will occur. When peeling, the starting point can be established at any desired position, but it is preferably located near r. In one embodiment, the position in which the starting point is established is approximately 0.8r to 1.2r.

[0042] 2) NEETs N The neat layer N is formed from a resin composition comprising a polypropylene resin, which is component (a), and optionally component (B). Component (a) is selected to satisfy the relationship between TmF and TmN. Component (a) is preferably selected from a propylene homopolymer (HOMO); or a propylene random copolymer (RACO) containing at least one comonomer selected from C2-C10-α-olefins (excluding C3-α-olefins) in an amount of 5% by weight or less; or a combination of these HOMO and RACO. If the amount of comonomer-derived units is excessively small, the fusion with layer F may not be sufficient, and if it is excessively large, the rigidity of the multilayer sheet may decrease. From this viewpoint, the amount of comonomer-derived units is preferably greater than 0% by weight and 4.5% by weight or less. Ethylene (C2-α-olefin) is preferred as the comonomer.

[0043] The MFR (at 230°C and under a load of 2.16 kg) of the polymer or resin composition constituting the neat layer N is preferably 1 to 15 g / 10 min, more preferably 2 to 10 g / 10 min, and even more preferably 3 to 8 g / 10 min. If the MFR is too low, it becomes difficult to manufacture the polypropylene resin used as the raw material, and if it is too high, breakage may occur during biaxial stretching, making it impossible to stably produce multilayer sheets.

[0044] [Weight ratio of components (a) and (B)] The weight ratio of components (a) and (B) in the neat layer N is preferably as follows: Component (B) / [Component (a) + Component (B)] = 0% by weight or more and less than 3% by weight In particular, in the manufacture of multilayer sheets, if the process includes co-extrusion to prepare a raw sheet, the strength of the sheet may decrease if the amount of component (B) in the raw sheet N'' (corresponding to the neat layer N of the multilayer sheet) is large. From this viewpoint, the weight ratio is preferably 1% by weight or less, more preferably 0.5% by weight or less, and most preferably 0% by weight. If the neat layer N contains component (B), its amount is less than the amount of component (B) in layer F.

[0045] 3) Method for manufacturing multilayer sheets The multilayer sheet is preferably manufactured by a method comprising: step 1, preparing a precursor in which filler layers F and neat layers N are laminated so that the filler layers F are not adjacent to each other; and step 2, bringing a heating element into contact with the outermost layer of the precursor to heat-fuse the layers of the sheet. At least one of the filler layers F in the precursor is layer FE. After step 2, a top layer 20 can be provided by a method such as painting. Alternatively, a multilayer sheet with a top layer 20 can be manufactured in one step by using a precursor with a top layer 20 provided as the precursor and going through steps 1 and 2. The method for manufacturing the multilayer sheet can be based on the method described in PCT / JP2021 / 041525. The contents of PCT / JP2021 / 041525 are incorporated herein by reference.

[0046] The manufacturing method will be described below with reference to Figures 3 and 4, using as an example an embodiment in which the top layer 20 is provided by a known method after step 2. The melting point TmF of the filler layer F and the melting point TmN of the neat layer N satisfy the relationship TmF > TmN, and preferably TmF - TmN ≥ 1 (°C). This difference in melting points results in good adhesion between the layers. In the figures, f, fe, and n are the resin compositions that ultimately constitute layer F, layer FE, and layer N. F'', FE'', and N'' are unstretched sheets (raw material sheets) that ultimately constitute layers F, FE, and N. F', FE', and N' are biaxially oriented sheet-like members that ultimately constitute layers F, FE, and N. 1' is the precursor, 1 is the multilayer sheet, F is the filler layer, FE is layer FE, and N is the neat layer. Also, 2 is the unstretched sheet preparation process, 3 is the stretching process, 4 is the lamination process, and 5 is the interlayer fusion process. The following relationships exist between the melting points Tmf (including Tmfe, the same applies hereinafter) and Tmn of the resin composition, the melting points TmF'' and TmN'' of the unstretched sheet, the melting points TmF' and TmN' of the biaxially oriented sheet-like members, and the melting points TmF and TmN of the layers. Tmf=TmF” TmF' = TmF = Tmf + x (°C) Tmn = TmN” TmN'=TmN=Tmn+y(℃) x and y vary depending on the stretching state, etc., but are preferably 1 to 10°C, and more preferably 2 to 7°C, respectively.

[0047] (1) Process 1 In this process, the precursor is prepared. A portion of the layers constituting the precursor may be composed of the aforementioned co-extruded layers. The entire precursor layer is either not fused or partially fused.

[0048] This process can be carried out, for example, by separately preparing a biaxially oriented polypropylene sheet member F' for the filler layer F and a biaxially oriented polypropylene sheet member N' for the neat layer N, and then alternately laminating them. For example, precursor 1' can be prepared by laminating them as F' / N' / ... / F'. In addition, at least one layer of the biaxially oriented polypropylene sheet member F' is a biaxially oriented polypropylene sheet member FE' for the easy-peel layer. The placement of the biaxially oriented polypropylene sheet member FE' is adjusted so that it is ultimately placed in the aforementioned position.

[0049] Figure 3 shows one embodiment of this process. In this embodiment, biaxially oriented polypropylene sheet members F', FE', and N' are prepared separately and laminated to prepare precursor 1'. In this case, it is preferable that all layers are not fused together, but one or more layers may be fused together. From the viewpoint of improving the heat resistance of the resulting sheet, it is preferable that both outermost layers are biaxially oriented polypropylene sheet members F'(FE').

[0050] The biaxially oriented polypropylene sheet-like member N' can be prepared by known methods. For example, a raw material sheet (unstretched polypropylene sheet-like member N") can be prepared from a raw material resin composition n, and this can be biaxially stretched by known methods to obtain the biaxially oriented polypropylene sheet-like member N'. The thickness of the raw material sheet is preferably greater than 0.15 mm, and although there is no upper limit, it is preferably 6 mm or less from the viewpoint of ease of handling, etc. The temperature during biaxial stretching is not limited, but it is preferably in the range of (TmN''-10℃) to TmN''.

[0051] Biaxially oriented polypropylene sheet-like member F' can be manufactured in the same way as biaxially oriented polypropylene sheet-like member N', but since it contains a relatively large amount of inorganic filler, it is preferable to set the temperature V during biaxial stretching to satisfy the following relationship. -3≦V-TmF”≦3 TmF'' is the melting point (°C) of the raw material sheet. The melting point Tmf of the resin composition can be determined by performing a DSC measurement under the condition of heating from 30°C to 230°C at a heating rate of 10°C / min, and TmF'' can be determined from the aforementioned relationship Tmf = TmF''.

[0052] The thickness of the raw material sheet is preferably greater than 0.15 mm, and although there is no upper limit, it is preferably 6 mm or less from the viewpoint of ease of handling. The stretch ratio is preferably 4 to 6 times with respect to one axis from the viewpoint of rigidity. The stretch ratio on one axis and the stretch ratio on the other axis may be the same or different. The two axes are preferably orthogonal.

[0053] This process is preferably carried out using a co-extruded sheet-like member having layer F and layer N. This simplifies process 2. This embodiment is shown in Figure 4. Specifically, a co-extruded raw material sheet C'' having multiple layers is prepared by co-extruding the raw materials for layer F and layer N, and a co-extruded biaxially oriented sheet-like member C' is prepared by biaxially stretching this sheet. The temperature V when biaxially stretching the co-extruded raw material sheet C'' is preferably selected to satisfy the above relationship. Next, a precursor 1' is prepared by laminating co-extruded biaxially oriented sheet-like members C' together, or co-extruded biaxially oriented sheet-like member C' with the aforementioned biaxially oriented sheet-like member F' or N'. In this case, the total number of co-extruded layers in precursor 1' is not limited, but 3 to 14 is preferred. The thickness of the co-extruded biaxially oriented sheet-like member C' is preferably 0.03 to 0.50 mm, and more preferably 0.03 to 0.30 mm.

[0054] As shown in Figure 4, a precursor can be obtained from a co-extruded biaxially oriented sheet-like member C', a biaxially oriented sheet-like member FE', and a biaxially oriented sheet-like member F', and a multilayer sheet can be manufactured. Precursor: FE' / C'[N / F / N] / F' Multilayer sheet: FE / N / F / N / F In the precursor, the layers F(E)' and C' are not fused together.

[0055] Furthermore, from the following precursors, the spaces between the central N layers are fused to obtain a three-layer multilayer sheet. Precursor: C'[FE / N] / C'[N / F] Multilayer sheet: FE / N / F

[0056] Alternatively, a precursor using a co-extruded 3-layer biaxially stretched sheet-like member is formed by fusing the two central N layers together to create a 5-layer multilayer sheet. Precursor: C'[FE / N] / C'[N / F / N] / C'[N / F] Multilayer sheet: FE / N / F / N / F

[0057] The single-layer biaxially oriented sheet member and the co-extruded biaxially oriented sheet member can each be placed in any direction. This placement allows for adjustment of the orientation direction within the multilayer sheet surface.

[0058] (2) Process 2 In this process (5 in Figures 3 and 4), a heating element is brought into contact with the outermost layer of the precursor 1' of the multilayer sheet to heat-fuse the layers together. The melting point Tm of the outermost layer out The temperature T of the heating element is Tm out It is preferable that the relationship -T≧4(°C) is satisfied. Satisfying this relationship allows for good interlayer fusion. From this viewpoint, a temperature difference of 6°C or more is more preferable. While there is no upper limit to the temperature difference, from the viewpoint of polypropylene manufacturing, it is preferably 40°C or less, and more preferably 30°C or less. T can be measured by any method, but it is preferable to measure it using a non-contact thermometer such as a radiation thermometer. Tm out This corresponds to the melting point of the outermost layer. This melting point is defined as the peak temperature of the melting curve obtained by measuring from 30°C to 230°C at a heating rate of 10°C / min using DSC.

[0059] The temperature T preferably satisfies the relationship TmF ≥ T ≥ TmN, and more preferably TmF ≥ T ≥ TmN + 10 (°C). If T exceeds the upper limit, the laminate may melt and its mechanical properties may deteriorate. If T is below the lower limit, the interlayers may not fuse sufficiently, and its mechanical properties may deteriorate. The specific temperature of the heating element is preferably around 120 to 190°C, more preferably 140 to 170°C, and even more preferably 150 to 165°C.

[0060] This process is preferably carried out continuously using a heated roll as the heating element. Specifically, the precursor of the multilayer sheet is passed between two heated rolls to fuse the layers together. Two rolls may be used as one set, and a heated roll consisting of two or more sets of rolls may be used as the heating element for fusion. The pressure applied at this time is adjusted as appropriate. The take-up speed in this roll forming is not limited, but is preferably about 0.05 to 10 m / min.

[0061] Other methods besides roll forming include pressure welding and fusion bonding. Furthermore, when heat-fusion bonding sheet-like members, it is preferable to apply pressure to suppress thermal shrinkage and further promote orientation. The pressure is adjusted according to the fusion temperature.

[0062] The adhesive layer 15 can be provided by known methods. The N layer can be used as the adhesive layer. Alternatively, oxygen-containing functional groups can be imparted to the surface of the multilayer sheet by subjecting it to plasma treatment or corona treatment, and this can be used as the adhesive layer. Or, oxygen-containing functional groups can be imparted to the surface of the multilayer sheet by preparing a polypropylene film having functional groups and preparing the precursor in step 1 such that the functional group-containing film becomes the outermost layer, and this can also be used as the adhesive layer.

[0063] Polypropylene films having oxygen-containing functional groups can be obtained by forming known polypropylenes, such as maleic anhydride-modified polypropylene or epoxy-modified polypropylene, into a film. The thickness of the functional group-containing film is not limited, but is preferably less than 150 μm. The functional group-containing film may or may not be biaxially oriented. In the lamination process, the polypropylene film having functional groups and a polypropylene sheet without functional groups may be laminated simultaneously, or a laminated sheet may be manufactured by laminating a polypropylene sheet without functional groups beforehand, and the polypropylene film having functional groups may be laminated onto the surface of the sheet. However, considering workability, the simultaneous lamination method is preferred.

[0064] In this embodiment, the top layer 20 can be provided by known methods. For example, it can be done by painting, attaching an aesthetically pleasing film or the like using an adhesive, etc.

[0065] (3) Other processes The manufacturing method may further include known steps such as cooling the multilayer sheet obtained in the preceding step. The cooling method is not limited, but examples include letting it cool at room temperature or cold pressing at room temperature or 10-20°C.

[0066] Because the multilayer sheets exhibit excellent interlayer adhesion, there are virtually no discontinuities between layers. Therefore, they can be treated as a single, integrated sheet. While conventional methods made it industrially impractical to obtain biaxially oriented multilayer sheets with a thickness of 0.20 mm or more from a cost perspective, this method allows for the industrial production of multilayer sheets with a thickness of 0.15 mm or more and orientation in two or more directions. [Examples]

[0067] I. When using plate-shaped inorganic filler 1. Preparation of sheet-like members Each of the sheet-like members shown in Table 1 was prepared as follows.

[0068] [Polymer 1] A solid catalyst used for polymerization was prepared by the method described in Example 1 of European Patent No. 674991. This solid catalyst consisted of Ti and diisobutyl phthalate as an internal donor supported on MgCl2 by the method described in the above patent publication. The solid catalyst (1) was contacted with triethylaluminum (TEAL) and dicyclopentyl dimethoxysilane (DCPMS) in amounts such that the weight ratio of TEAL to the solid catalyst was 11 and the weight ratio of TEAL / DCPMS was 10, at -5°C for 5 minutes. The resulting catalyst system was prepolymerized by holding it in a suspension state in liquid propylene at 20°C for 5 minutes. After introducing the obtained prepolymer into a polymerization reactor, hydrogen and propylene were fed in, and the polymerization temperature and hydrogen concentration were set to 75°C and 0.24 mol%, respectively, and the pressure was adjusted to obtain polymer 1 as a propylene homopolymer. The MFR (temperature 230°C, load 2.16 kg) of polymer 1 (component (A) = component (A1)) was 7.5 g / 10 min.

[0069] [Resin composition (a)] 60 parts by weight of polymer 1 were mixed with 40 parts by weight of talc (Neo-talc UNI05 manufactured by Neo-Light Kogyo Co., Ltd. (volume-average particle size measured by laser diffraction: 5 μm)), 0.2 parts by weight of antioxidant (BASF B225), and 0.05 parts by weight of neutralizing agent (calcium stearate manufactured by Tannan Chemical Industry Co., Ltd.), and stirred in a Henschel mixer for 1 minute. The mixture was melt-kneaded at a cylinder temperature of 230°C using a Nakatani Machinery Co., Ltd. NVC φ50 mm single-screw extruder, and the extruded strands were cooled in water and then cut with a pelletizer to obtain pelletized resin composition (a). The MFR (temperature 230°C, load 2.16 kg) of resin composition (a) was 7.5 g / 10 min.

[0070] [polymer2] The above solid catalyst (1) was contacted with TEAL and dicyclopentyl dimethoxysilane (DCPMS) in amounts such that the weight ratio of TEAL to the solid catalyst was 11 and the weight ratio of TEAL / DCPMS was 3, at -5°C for 5 minutes. The resulting catalyst system was prepolymerized by holding it in a suspended state in liquid propylene at 20°C for 5 minutes. After introducing the obtained prepolymer into a polymerization reactor, hydrogen, propylene, and ethylene were fed in. Polymer 2 was obtained as a propylene-ethylene copolymer by adjusting the polymerization pressure at a polymerization temperature of 75°C, a hydrogen concentration of 0.44 mol%, and an ethylene concentration of 1.07 mol%. Polymer 2 (component (A) = component (A1), hereinafter simply referred to as "PP component") contained 4.0 wt% ethylene-derived units (hereinafter simply referred to as "C2"), and the MFR (temperature 230°C, load 2.16 kg) was 7.5 g / 10 min.

[0071] [Resin composition (b)] 100 parts by weight of polymer 2 were mixed with 0.2 parts by weight of an antioxidant (BASF B225) and 0.05 parts by weight of a neutralizing agent (calcium stearate manufactured by Tannan Chemical Industry Co., Ltd.), and stirred in a Henschel mixer for 1 minute. The mixture was melt-kneaded at a cylinder temperature of 230°C using a Nakatani Machinery Co., Ltd. NVC φ50 mm single-screw extruder, and the extruded strands were cooled in water and then cut with a pelletizer to obtain pelletized resin composition (b). Resin composition (b) had an MFR (temperature 230°C, load 2.16 kg) of 7.5 g / 10 min.

[0072] [Polymer 3] A solid catalyst used for polymerization was prepared by the method described in Example 1 of Japanese Patent Application Publication No. 2011-500907. This solid catalyst consisted of Ti and diethyl-2,3-(diisopropyl) succinate as an internal donor supported on MgCl2 by the method described in the above patent publication. The solid catalyst (1) was contacted with triethylaluminum (TEAL) and dicyclopentyl dimethoxysilane (DCPMS) in amounts such that the weight ratio of TEAL to the solid catalyst was 11 and the weight ratio of TEAL / DCPMS was 15, at 12°C for 24 minutes. The resulting catalyst system was prepolymerized by holding it in a suspension state in liquid propylene at 20°C for 5 minutes. After introducing the obtained prepolymer into a polymerization reactor, hydrogen, propylene, and ethylene were fed in. Polymer 3 was obtained as a propylene-ethylene copolymer by adjusting the polymerization pressure at a polymerization temperature of 80°C, a hydrogen concentration of 0.16 mol%, and an ethylene concentration of 0.08 mol%. Polymer 3 (PP component) contained 0.35% by weight of C2, and its MFR (temperature 230°C, load 2.16 kg) was 4.2 g / 10 min.

[0073] [Resin composition (c)] 100 parts by weight of polymer 3 were mixed with 0.2 parts by weight of an antioxidant (BASF B225) and 0.05 parts by weight of a neutralizing agent (calcium stearate manufactured by Tannan Chemical Industry Co., Ltd.), and stirred in a Henschel mixer for 1 minute. The mixture was melt-kneaded at a cylinder temperature of 230°C using a Nakatani Machinery Co., Ltd. NVC φ50 mm single-screw extruder, and the extruded strands were cooled in water and then cut with a pelletizer to obtain pelletized resin composition (c). Resin composition (c) had an MFR (temperature 230°C, load 2.16 kg) of 4.2 g / 10 min.

[0074] [Resin composition (d)] Resin composition (d) was obtained in the same manner as resin composition (a), except that polymer 3 was changed to 92 parts by weight and the talc to 8 parts by weight. The MFR (temperature 230°C, load 2.16 kg) of resin composition (d) was 4.9 g / 10 min.

[0075] [Polymer 4] Polymer 4 was obtained in the same manner as Polymer 1, except that the hydrogen concentration was changed to 0.14 mol%.

[0076] [Talc Masterbatch Resin Composition (e)] (MB) A mixture was obtained by stirring 50 parts by weight of polymer 4, 50 parts by weight of the above talc, 0.1 parts by weight of BASF B225 as an antioxidant, and 0.05 parts by weight of calcium stearate manufactured by Tannan Chemical Industry Co., Ltd. as a neutralizing agent in a Henschel mixer for 1 minute. Next, the mixture was subjected to melt kneading (twin-screw extruder melt kneading) in an extruder (TEX-30α co-directional twin-screw extruder manufactured by Japan Steel Works Ltd.) set to a screw temperature of 230°C. Furthermore, the molten mixture was discharged from the extruder and cooled to form strands, and the strands were cut to obtain pellets of talc masterbatch resin composition (e). The MFR (temperature 230°C, load 2.16 kg) of resin composition (e) was 4.3 g / 10 min.

[0077] [Resin composition (f)~(j)] Resin compositions (f) to (j) with MFRs (temperature 230°C, load 2.16 kg) as shown in Table 1 were obtained in the same manner as resin composition (a), except that the talc masterbatch resin composition (e) was added to polymer 1 in place of the talc, such that the talc content in the composition was as shown in Table 1.

[0078] [Biaxially oriented sheet QN-1] Using a 25mmφ 3-type 3-layer film / sheet molding machine (manufactured by Thermo Plastics Industry Co., Ltd.), the resin composition (c) was co-extruded at a molding temperature of 230°C so that resin composition (b) was on the touch roll side and resin composition (b) was on the cast roll side, obtaining a raw sheet with a thickness of 2.5mm (size 10cm x 10cm or larger). The raw sheet was simultaneously biaxially stretched (3.5 times x 3.5 times) at 165°C using a film stretching device (KARO-IV, manufactured by Bruckner GmbH) to obtain a co-extruded biaxially oriented sheet QN-1 with a thickness of 0.20mm. The thickness ratio of resin composition (c) / resin composition (b) was 91 / 9. The "Q" layer is a layer that can be used as a top layer.

[0079] [Biaxially oriented film QN-2] Using a 25mmφ 3-type 3-layer film / sheet molding machine (manufactured by Thermo Plastics Industry Co., Ltd.), the resin composition (c) was co-extruded at a molding temperature of 230°C so that resin composition (b) was on the touch roll side and resin composition (b) was on the cast roll side to obtain a raw sheet with a thickness of 1.0 mm (size 10 cm × 10 cm or larger). The raw sheet was simultaneously biaxially stretched (5 times × 5 times) at 165°C using a film stretching device (KARO-IV, manufactured by Bruckner GmbH) to obtain a co-extruded biaxially oriented film QN-2 with a thickness of 0.035 mm. The thickness ratio of resin composition (c) / resin composition (b) was 91 / 9.

[0080] [Biaxially oriented sheet NQ-1, biaxially oriented film NQ-2] Except for the resin composition (b) being on the touch roll side and resin composition (c) being on the cast roll side, the materials were co-extruded in the same manner as QN-1 and QN-2 to obtain raw material sheets (size 10cm × 10cm or larger) with thicknesses of 2.5mm and 1.0mm, respectively. The raw material sheets were simultaneously biaxially stretched at 165°C using a film stretching machine (KARO-IV, manufactured by Bruckner) to obtain a co-extruded biaxially oriented sheet NQ-1 with a thickness of 0.20mm and a co-extruded biaxially oriented film NQ-2 with a thickness of 0.035mm. The stretching ratio of the former was 3.5x3.5x, and the stretching ratio of the latter was 5x5x. The thickness ratio of resin composition (b) / resin composition (c) was 9 / 91.

[0081] [Biaxially oriented sheets NQN, NFN-1~8] Using a 25mmφ 3-type 3-layer film / sheet molding machine (manufactured by Thermo Plastics Industry Co., Ltd.), the resin compositions (b) / (c), (a), (d), (f)~(j), (e) / (b) were co-extruded at a molding temperature of 230°C to obtain raw material sheets (size 10cm × 10cm or larger) with a thickness of 1.0mm to 2.5mm. The raw material sheets were simultaneously biaxially stretched (3.5x × 3.5x or 5x × 5x) at 165°C using a film stretching device (KARO-IV, manufactured by Bruckner), to obtain co-extruded biaxially oriented sheets with a thickness of 0.035 to 0.20mm. The thickness ratio was 8 / 84 / 8.

[0082] [Unextended Sheet NFN_U] Using a 25mmφ 3-type 3-layer film / sheet molding machine (manufactured by Thermo Plastics Industry Co., Ltd.), the resin composition (b) / resin composition (j) / resin composition (b) was co-extruded at a molding temperature of 230°C to obtain a sheet with a thickness of 0.05 mm (size 10 cm x 10 cm or larger), which was designated as the unstretched sheet NFN_U.

[0083] [Unextended Sheet NQN_U] Using a 25mmφ 3-type 3-layer film / sheet molding machine (manufactured by Thermo Plastics Industry Co., Ltd.), the resin composition (b) / resin composition (c) / resin composition (b) was co-extruded at a molding temperature of 230°C to obtain a sheet with a thickness of 1.0 mm (size 10 cm x 10 cm or larger), which was designated as the unstretched sheet NQN_U.

[0084] [Injection molded product Y_U] A 3.0 mm thick raw material sheet was prepared by injection molding using pellets of resin composition (a).

[0085] 2. Manufacturing of multilayer sheets [Example 1] Six sheets of NFN-1 were stacked, with QN-1 as the top layer and NQ-1 as the bottom layer to prepare a precursor. A multilayer sheet was manufactured as a laminate by heat-fusing the layers of the precursor using a heating element and a press molding machine manufactured by Shoji Co., Ltd. heated to 160°C. During pressing, both sides of the precursor were sandwiched between a 3mm thick aluminum plate and a 1mm thick steel plate from the outside and pressed at 4MPa for 2 minutes. In this way, a 1.3mm thick multilayer sheet was manufactured. In addition, a 55μm thick polyimide tape was inserted into a portion of a specific interlayer during this heat-fusing process to prevent fusion in that area, thereby creating a gripping area for the peeling strength test. Since the polyimide tape and polypropylene do not fuse, it can be easily removed before the peeling strength test. The interface where the polyimide tape was inserted is indicated by " / / ". The peeling strength of the multilayer sheet was measured using the method described later, and the results are shown in Table 2. Material fracture was observed in layer FE, which is closest to QN-1 (top layer), confirming that this layer functions as an easy-peel layer. Figure 5 shows the delamination state of the multilayer sheet (photograph), and Figure 6 shows a schematic diagram thereof. In Figure 6, the right side shows an enlarged view of the area enclosed by the dotted line. The dotted line in this enlarged view represents the formation of a crack.

[0086] [Example 2] The layer configuration was as shown in Table 2, and a multilayer sheet was manufactured and evaluated in the same manner as in Example 1. Material fracture was observed in the layer FE closest to the top layer, confirming that this layer functions as an easy-peel layer.

[0087] [Comparative Examples 1-3] The layer configuration was as shown in Table 2, and a multilayer sheet was manufactured and evaluated in the same manner as in Example 1. In this example, a sheet-like material containing talc was not used. In the peeling test, the gripping portion fractured.

[0088] The layer structure is shown below. Examples 1 QN-1 / / NFN-1×6 / NQ-1 2 QN-1 / QN-1 / / NFN-2 / Y_U Comparative Example 1 QN-1 / / NQN-1×4 / NQ-1 2 QN-1 / NQN-1 / / Y_U 3 QN-1 / NQN-1 / / NQN-1 / IY_U

[0089] [Examples 3-8] The layer configuration was as shown in Table 2, and a multilayer sheet was manufactured and evaluated in the same manner as in Example 1. In each example, material fracture was observed in layer FE, confirming that it functions as an easy-peel layer. For example, the relationship between the precursor and the multilayer sheet in Example 3 is as follows. In Example 3, when the surface layer (top layer) is considered the first layer, material fracture occurred in layer FE, which is located in the eighth layer. Precursor: (upper layer) NQN_U / NFN-3 / NFN-3 / NFN-3 / / NFN-3 / NFN-3 / NFN-3 / NQN_U (lower layer) Multilayer sheet: (Upper layer) N / Q / N / F / N / F / N / F / N / F / N / F / N / F / N / Q / N (Lower layer) Thus, it became clear that the layer FE exhibits easy-peel properties even when it is located at a relatively deep position (far from the surface).

[0090] [Comparative Examples 4 and 5] The layer configuration was as shown in Table 2, and a multilayer sheet was manufactured and evaluated in the same manner as in Example 1. In this example, a sheet-like material containing unstretched talc was used. For example, in Comparative Example 5, 43 sheets of NFN_U were stacked, and a 55 μm thick polyimide tape was inserted in a portion between the 6th and 7th sheets to manufacture a multilayer sheet in the same manner as in Example 1. In the peeling test, the gripping portion broke. It was confirmed that the sheet-like material containing unstretched talc does not function as an easy-peel layer.

[0091] The layer structure is shown below. Examples 3 NQN_U / NFN-3 / NFN-3 / NFN-3 / / NFN-3 / NFN-3 / NFN-3 / NQN_U 4 NQN_U / NFN-4 / NFN-4 / NFN-4 / / NFN-4 / NFN-4 / NFN-4 / NQN_U 5 NQN_U / NFN-5 / NFN-5 / NFN-5 / / NFN-5 / NFN-5 / NFN-5 / NQN_U 6 NQN_U / NFN-6 / NFN-6 / NFN-6 / / NFN-6 / NFN-6 / NFN-6 / NQN_U 7 NQN_U / NFN-7 / NFN-7 / NFN-7 / / NFN-7 / NFN-7 / NFN-7 / NQN_U 8 NQN_U / NFN-8 / NFN-8 / NFN-8 / / NFN-8 / NFN-8 / NFN-8 / NQN_U Comparative Example 4 NFN_U×6 / / NFN_U×37 5 NFN_U×21 / / NFN_U×22

[0092] [Examples 9-13] The layer configuration was as shown in Table 2, and multilayer sheets were manufactured and evaluated in the same manner as in Example 1. In each example, material fracture was observed in layer FE, confirming that this layer functions as an easy-peel layer. Furthermore, it was revealed that when the biaxially oriented sheet contains 20-40% by weight of talc, the easy-peel layer exhibits easy-peel properties even when it is located at a relatively shallow position (close to the surface).

[0093] The layer structure is shown below. Examples 9 NFN-4 / NFN-4 / NFN-4 / / NFN-4 / NFN-4 / NFN-4 / NQN_U / NQN_U 10 NFN-5 / NFN-5 / NFN-5 / / NFN-5 / NFN-5 / NFN-5 / NQN_U / NQN_U 11 NFN-6 / NFN-6 / NFN-6 / / NFN-6 / NFN-6 / NFN-6 / NQN_U / NQN_U 12 NFN-7×5 / / NFN-7×58 13 QN-2 / NFN-7×2 / / NFN-7×3 / NQN_U / NQN_U

[0094] [Table 1-1]

[0095] [Table 1-2]

[0096] [Table 2-1]

[0097] [Table 2-2]

[0098] [Table 2-3]

[0099] II. When using granular inorganic fillers 1. Preparation of sheet-like members [Polymer 5] Polymer 5 was obtained in the same manner as Polymer 2, except that the hydrogen concentration was changed to 0.22 mol% and the ethylene concentration to 0.58 mol%. Polymer 5 contained 2.2 wt% C2, and its MFR (temperature 230°C, load 2.16 kg) was 5.0 g / 10 min.

[0100] [Resin composition (k)] 100 parts by weight of polymer 5 were mixed with 0.2 parts by weight of an antioxidant (BASF B225) and 0.05 parts by weight of a neutralizing agent (calcium stearate manufactured by Tannan Chemical Industry Co., Ltd.), and stirred in a Henschel mixer for 1 minute. The mixture was melt-kneaded at a cylinder temperature of 230°C using a Nakatani Machinery Co., Ltd. NVC φ50 mm single-screw extruder, and the extruded strands were cooled in water and then cut with a pelletizer to obtain pelletized resin composition (k). The MFR (temperature 230°C, load 2.16 kg) of resin composition (k) was 5.0 g / 10 min.

[0101] [Modification 6] A solid catalyst, in which Ti and diisobutyl phthalate as an internal donor are supported on MgCl2, was prepared by the method described in paragraph 0032, lines 21-36 of Japanese Patent Application Publication No. 2004-27218. Next, the solid catalyst was brought into contact with triethylaluminum (TEAL) as an organoaluminum compound and dicyclopentyl dimethoxysilane (DCPMS) as an external electron donor compound in amounts such that the weight ratio of TEAL to the solid catalyst was 20 and the weight ratio of TEAL / DCPMS was 10 (equivalent to 0.05 in the molar ratio of the organosilicon compound / organoaluminum compound mentioned above) at 12°C for 24 minutes. The resulting catalyst system was prepolymerized by holding it in a suspension state in liquid propylene at 20°C for 5 minutes. The obtained prepolymer was introduced into the first stage polymerization reactor of a polymerization apparatus equipped with two polymerization reactors in series, and propylene was supplied to produce a propylene homopolymer (component (A1)). Subsequently, the propylene homopolymer, propylene, and ethylene were supplied to the second stage polymerization reactor to produce an ethylene-propylene copolymer (component (A2)). During polymerization, the temperature and pressure were adjusted, and hydrogen was used as a molecular weight modifier. The polymerization temperature and reactant ratios were as follows: in the first reactor, the polymerization temperature and hydrogen concentration were 80°C and 0.77 mol%, respectively; and in the second reactor, the polymerization temperature, hydrogen concentration, and the ratio of ethylene to the total of ethylene and propylene were 80°C, 1.61 mol%, and 0.50 mol%, respectively. The polymerization times for the first and second stages were adjusted so that the weight ratio of component (A2) / [component (A1) + component (A2)] was 18.5% by weight. By this method, the target polymer 6 was obtained.

[0102] The resulting polymer 6 is a polymerized mixture of component (A1), which is a propylene polymer constituting the continuous phase, and component (A2), which is an ethylene-propylene copolymer constituting the rubber phase, and is the aforementioned polypropylene resin (A). The ethylene-derived unit content (C2) of component (A1), the weight ratio of component (A2) / [component (A1) + component (A2)], the ethylene-derived unit content of component (A2), and the MFR of component (A1) + component (A2) of polymer 6 were 0% by weight, 18.5% by weight, 51% by weight, and 16.5 g / 10 min, respectively.

[0103] [Resin composition (l)] 100 parts by weight of polymer 6 were mixed with 0.2 parts by weight of an antioxidant (BASF B225) and 0.05 parts by weight of a neutralizing agent (calcium stearate manufactured by Tannan Chemical Industry Co., Ltd.), and stirred in a Henschel mixer for 1 minute. The mixture was melt-kneaded at a cylinder temperature of 230°C using a Nakatani Machinery Co., Ltd. NVC φ50 mm single-screw extruder, and the extruded strands were cooled in water and then cut with a pelletizer to obtain pelletized resin composition (l). The MFR (temperature 230°C, load 2.16 kg) of resin composition (l) was 16.5 g / 10 min.

[0104] [Calcium carbonate masterbatch resin composition (m)] (MB2) A mixture was obtained by stirring a 35% by weight resin composition (l) with 54.9% by weight calcium carbonate (NN#500, manufactured by Nitto Funka Kogyo Co., Ltd.), 10% by weight acid-modified polypropylene (ER321P, manufactured by Mitsubishi Chemical Corporation), and 0.1 parts by weight dimyristilthiodipropionate (Yoshinox DMTP, manufactured by Yoshitomi Pharmaceutical Co., Ltd.) as an antioxidant in a Henschel mixer for 1 minute. Next, the mixture was subjected to melt kneading (twin-screw extruder melt kneading) in an extruder (TEX-30α co-directional twin-screw extruder, manufactured by Japan Steel Works Ltd.) set to a screw temperature of 230°C. Furthermore, the molten mixture was discharged from the extruder, cooled to form strands, and the strands were cut to obtain pellets of calcium carbonate masterbatch resin composition (m). The MFR (temperature 230°C, load 2.16 kg) of masterbatch resin composition (m) was 8.0 g / 10 min.

[0105] [Resin composition (n)~(q)] Resin composition (c) and the calcium carbonate masterbatch resin composition (m) were dry-blended to obtain resin compositions (n) to (q) so that the calcium carbonate content in the compositions was as shown in Table 3. The blend ratios of resin composition (c):calcium carbonate masterbatch resin composition (m) in resin compositions (n) to (q) were 9:1 for resin composition (n), 8:2 for resin composition (o), 6:4 for resin composition (p), and 4:6 for resin composition (q), respectively.

[0106] [Biaxially oriented sheet NFN-9~12] Using a 25mmφ 3-type 3-layer film / sheet molding machine (manufactured by Thermo Plastics Industry Co., Ltd.), the resin compositions (k) / (n) to (q) / (k) were co-extruded at a molding temperature of 250°C to obtain a 1.0mm thick raw sheet (size 10cm x 10cm or larger). The raw sheet was simultaneously biaxially stretched (6x6) at 165°C using a film stretching device (KARO-IV, manufactured by Bruckner), obtaining co-extruded biaxially oriented sheets NFN-9 to NFN-12 with a thickness of 0.025mm. The thickness ratio was 10 / 80 / 10.

[0107] [NQN_U-2] Using a 25mmφ 3-type 3-layer film / sheet molding machine (manufactured by Thermo Plastics Industry Co., Ltd.), the resin composition (k) / resin composition (c) / resin composition (k) was co-extruded at a molding temperature of 250°C to obtain a raw sheet with a thickness of 1.0 mm (size 10 cm x 10 cm or larger), which was designated as the unstretched sheet NQN_U-2.

[0108] [Biaxially oriented sheet NQN-2] Using a film stretching apparatus (KARO-IV manufactured by Bruckner), an unstretched raw material sheet NQN_U-2 was simultaneously biaxially stretched (6x6x) at 165°C to obtain a co-extruded biaxially oriented sheet NQN-2 with a thickness of 0.025 mm. The thickness ratio was 10 / 80 / 10. The physical properties of these sheets are shown in Table 3.

[0109] 2. Manufacturing of multilayer sheets [ reference Example 14] Six sheets of NFN-9 were stacked, and a polyimide tape was inserted between the third and fourth layers from the top. NQN-2 was further stacked on top of this laminate, and two sheets of NQN_U were placed below it to prepare a precursor. Using a heating element and a press molding machine manufactured by Shoji Co., Ltd. heated to 160°C, the layers of the precursor were heat-fused together to produce a multilayer sheet as a laminate. During pressing, both sides of the precursor were sandwiched from the outside between a 3mm thick aluminum plate and a 1mm thick steel plate, and pressed at 4MPa for 2 minutes. In this way, a 2.2mm thick multilayer sheet was produced. The peeling strength of this multilayer sheet was measured using the method described later, and the results are shown in Table 3. When the surface layer (top layer) is considered the first layer, material fracture was observed in layer FE, which is located in the eighth layer, confirming that this layer functions as an easy-peel layer. The results are shown in Table 4.

[0110] [ reference [Examples 15-18] Except for changing the layer structure of the precursor as shown in the table, reference A multilayer sheet was manufactured and evaluated using the same method as in Example 14. As a result, material fracture was observed in layer FE, confirming that this layer functions as an easy-peel layer. The results are shown in Table 4.

[0111] The layer structure is shown below. reference example 14 NQN-2 / NFN-9×3 / / NFN-9×3 / NQN_U / NQN_U 15 NQN-2 / NFN-10×3 / / NFN-10×3 / NQN_U / NQN_U 16 NQN_U-2 / NFN-11×2 / / NFN-11×2 / NQN_U-2×7 17 NQN_U-2 / NFN-12×2 / / NFN-12×2 / NQN_U-2×7 18 NQN_U-2×2 / NFN-12×2 / / NFN-12×2 / NQN_U-2×7

[0112] [Table 3]

[0113] [Table 4]

[0114] [Evaluation Method] [Total ethylene content of component (A) (component (A1) + component (A2)), ethylene-derived unit content of component (A1)] For copolymer samples dissolved in a mixed solvent of 1,2,4-trichlorobenzene / deuterated benzene / hexamethyldisiloxane = 30 / 10 / 1 (volume ratio), a Bruker AVANCE III HD400 was used. 13 Using a C resonance frequency of 100 MHz, under the following conditions: measurement temperature 120°C, flip angle 45 degrees, pulse interval 7 seconds, sample rotation speed 20 Hz, and number of integrations 6000 times. 13 The 1C-NMR spectrum was obtained. Using the spectrum obtained above, the total ethylene content (weight %) of component (A) was determined by the method described in the literature Kakugo, Y. Naito, K. Mizunuma and T. Miyatake, Macromolecules, 15, 1150-1152 (1982). Note that when component (A1) is used as the sample for measurement, the total ethylene content (weight %) obtained by the above method represents the ethylene unit content (weight %) of component (A1). Furthermore, if component (A1) contains comonomer-derived units other than ethylene, the content of those comonomer units is determined in the same way as the content of ethylene-derived units.

[0115] [Ethylene unit content in component (A2)] Except for using the integral intensity T'ββ obtained by the following formula instead of the integral intensity Tββ obtained when measuring the total ethylene content of component (A) using the method described in the above-mentioned literature, the ethylene unit content (weight %) of component (A2) was calculated using the same method as for the total ethylene content. T'ββ=0.98×Sαγ×A' / (1-0.98×A') Here, A' = Sαγ / (Sαγ+Sαδ), and Sαγ and Sαδ are as described in the above-mentioned literature. It is calculated from this. Furthermore, in a component (A) consisting of component (A1) and component (A2), if component (A1) contains ethylene units, the ethylene-derived unit content in component (A2) was determined by the following formula, provided that the weight ratio (component (A2) / [component (A1) + component (A2)]) was clear from the polymerization conditions. Ethylene-derived unit content of component (A2) (unit: weight %) = [Total ethylene content of component (A) - Ethylene-derived unit content of component (A1) × Percentage of component (A1) in component (A)] / (Percentage of component (A2) in component (A))

[0116] [Weight ratio component (A2) / [component (A1) + component (A2)]] It was calculated using the following formula. Component (A2) / [Component (A1) + Component (A2)] (Unit: weight %) = Total ethylene content of Component (A) / (Ethylene unit content in Component (A2) / 100)

[0117] [Liquidity MFR] The MFR of polypropylene resin was measured by adding 0.05 g of H-BHT manufactured by Honshu Chemical Industry Co., Ltd. to 5 g of sample, homogenizing it by dry blending, and then measuring it in accordance with JIS K7210-1 and JIS K6921-2 under conditions of 230°C and a load of 2.16 kg. The MFR of the polypropylene resin composition was measured in accordance with JIS K7210-1 and based on JIS K6921-2 under conditions of a temperature of 230°C and a load of 2.16 kg.

[0118] [Peeling test] A 180-degree peel test was conducted using an Autocom universal testing machine manufactured by TSE Corporation. The sheet manufactured in the above example was cut into strips with a width of 15 mm to form test specimens. The top layer and bottom layer were each clamped. The distance between the clamps was set to 50 mm, and a tensile test was performed by moving the clamps at a speed of 300 mm / min. The tensile force was applied for a length of 100 mm or more, and the average value of the test force in the stable 50 mm section during material fracture was used as the test value. [Explanation of Symbols]

[0119] 10 Easy Peel Layers 15 Adhesive layer 20 Top Tier 30 Other layers 1 Multilayer sheet F Filler layer F FE filler layer FE N NEET layer N 1' Precursor F' Biaxially oriented polypropylene sheet-like member FE' Biaxially oriented polypropylene sheet-like member N' Biaxially oriented polypropylene sheet-like member resin composition constituting layer f F Resin composition constituting the fe layer FE Resin composition constituting n layer N F' Unstretched polypropylene sheet (raw sheet) FE” Unstretched polypropylene sheet (raw sheet) N” Unstretched polypropylene sheet (raw sheet) C' Biaxially oriented co-extruded sheet-like member 2. Unstretched Sheet Preparation Process 3 Stretching process 4 Lamination process 5 Interlayer fusion process

Claims

1. A stretched sheet comprising a polypropylene resin as component (A) and a plate-shaped inorganic filler as component (B), The weight ratio of component (B) / [component (A) + component (B)] is 3 to 50% by weight. Sheet for the Easy Peel layer.

2. The aforementioned component (A) is a polypropylene resin consisting of component (A1) and an optional component (A2). The above component (A1) is a propylene (co)polymer containing 0 to 10% by weight of comonomer-derived units selected from C2 to C10-α-olefins (excluding C3-α-olefins), 100 to 50% by weight. Component (A2) is an ethylene-α-olefin copolymer containing more than 10% by weight and 90% by weight or less of ethylene-derived units, and is 0 to 50% by weight. The MFR of component (A) (230°C, load 2.16 kg) is 1 to 15 g / 10 min. The sheet according to claim 1.

3. The sheet according to claim 1 or 2, wherein the component (B) is selected from the group consisting of talc, mica, and combinations thereof.

4. The sheet according to claim 3, wherein the component (B) is talc.

5. The sheet according to any one of claims 1 to 4, which is a biaxially oriented sheet.

6. A product comprising a sheet according to any one of claims 1 to 5 as an easy-peel layer.

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