Multilayer body

Abstract

Provided is a multilayer body having a protective film including an adhesive layer on the surface of a thin polycarbonate film, the multilayer body being less susceptible to the occurrence of orange peel on the surface of the polycarbonate film when the protective film is peeled off. The multilayer body has a polycarbonate film having a thickness of 20-75 [mu] m and a protective film provided on at least one surface of the polycarbonate film, the protective film has an adhesive layer that is peelable from the polycarbonate film and a resin-containing layer, the adhesive layer is in contact with the polycarbonate film, and when the polycarbonate film is peelable from the multilayer body, the adhesive layer is in contact with the polycarbonate film. The arithmetic average waviness Ma of the corrugations of the adhesive layer is 0.01-0.12 [mu] m, and the corrugations do not include corrugations having a corrugation width of less than 500 [mu] m and greater than 3000 [mu] m.

Description

Technical Field

[0001] The present invention relates to a multilayer body, and more particularly to a multilayer body having a thin polycarbonate film and a protective film. Background Art

[0002] In order to manufacture a film roll for optical use, etc., an attempt has been made to laminate a protective film having an adhesive layer on a polycarbonate film and roll it up. That is, a protective film having an adhesive layer is attached and laminated on a flat polycarbonate film for optical use to protect the surface, and the surface on the opposite side of the protective film is appropriately roughened to form a structure that is easy to slide (having slipperiness), so that a multilayer body laminated with the film can be rolled up.

[0003] Such a multilayer body is described in Patent Document 1, for example.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2008 / 153032 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] As described above, in order to make the protective film of the multilayer body have slipperiness, when the surface is given unevenness, it is found that when the thickness of the polycarbonate film is thin, the layers are stacked and passed through rollers. Due to the conditions during bonding (such as the pressure of the bonding rollers, etc.) or the subsequent storage state, the unevenness of the outermost layer will be printed on the polycarbonate film, resulting in orange peel texture on the surface of the polycarbonate film.

[0009] The present invention aims to solve the above-mentioned technical problems and aims to provide a multilayer body having a protective film including an adhesive layer on the surface of a thin polycarbonate film, wherein when the protective film is peeled off, the surface of the polycarbonate film is less likely to produce orange peel.

[0010] Technical solutions for solving technical problems

[0011] The inventors of the present invention have studied the above technical problems and found that the above technical problems can be solved by adjusting the surface of the adhesive layer in contact with the polycarbonate film to have a predetermined waviness when peeling the protective film from the multilayer body.

[0012] The above technical problems are specifically solved by utilizing the following solutions.

[0013] <1> A multilayer body comprising: a polycarbonate film having a thickness of 20 to 75 μm; and a protective film provided on at least one surface of the polycarbonate film,

[0014] The protective film comprises an adhesive layer that can be peeled from the polycarbonate film and a layer containing a resin.

[0015] The adhesive layer is in contact with the polycarbonate film, and

[0016] When the polycarbonate film is peeled off from the multilayer body, the arithmetic mean waviness Ma of the adhesive layer is 0.01 to 0.12 μm, and the waviness does not include waviness with a width of less than 500 μm and greater than 3000 μm.

[0017] <2> The multilayer body according to <1>, wherein the polycarbonate film has a thickness of less than 67 μm.

[0018] <3> The multilayer body according to <1> or <2>, wherein the resin-containing layer contains a polyolefin resin and / or a polyester resin.

[0019] <4> The multilayer body according to <1> or <2>, wherein the multilayer body comprises the protective films on both sides of the polycarbonate film,

[0020] The above-mentioned resin-containing layers each contain a polyolefin resin.

[0021] <5> The multilayer body according to <1> or <2>, wherein the multilayer body comprises the protective films on both surfaces of the polycarbonate film,

[0022] The resin-containing layer on one surface of the polycarbonate film contains a polyolefin resin, and the resin-containing layer on the other surface of the polycarbonate film contains a polyester resin.

[0023] <6> The multilayer body according to <1> or <2>, wherein the multilayer body comprises the protective films on both sides of the polycarbonate film.

[0024] The above-mentioned resin-containing layers each contain a polyester resin.

[0025] <7> The multilayer body according to any one of <1> to <6>, wherein the number of point defects on the surface of the resin-containing layer is 2000 / m 2 the following.

[0026] <8> The multilayer body according to any one of <1> to <7>, which satisfies any one of the following conditions (1) and (2),

[0027] (1) The tensile elastic modulus of the multilayer body is 1800 MPa or more;

[0028] (2) The tensile modulus of the multilayer body is less than 1800 MPa, and the arithmetic mean waviness Wa of the outermost layer of the resin-containing layer is greater than 0.15 μm, excluding those with a width less than 500 μm and greater than 3000 μm.

[0029] <9> A multilayer body as described in any one of <1> to <8>, wherein the arithmetic mean waviness Wa of the layer on the outermost side of the resin-containing layer is 0.03 to 0.35 μm, and the above-mentioned waviness does not include waviness with a width less than 500 μm and greater than 3000 μm.

[0030] <10> A multilayer body as described in any one of <1> to <8>, wherein the arithmetic mean waviness Wa of the layer on the outermost side of the resin-containing layer is 0.03 to 0.30 μm, and the above-mentioned waviness does not include waviness with a width less than 500 μm and greater than 3000 μm.

[0031] <11> The multilayer body according to any one of <1> to <10>, wherein the haze is 30% or less.

[0032] <12> The multilayer body according to any one of <1> to <10>, wherein the haze is 10% or less.

[0033] <13> The multilayer body according to any one of <1> to <12>, wherein the polycarbonate film has a glass transition temperature of 115 to 142°C as measured by differential scanning calorimetry (DSC).

[0034] <14> The multilayer body according to any one of <1> to <13>, wherein the polycarbonate film contains a polycarbonate having a terminal structure represented by formula (1).

[0035]

[0036] (In formula (1), R 1 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms. 2 Each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 6 to 12 carbon atoms. n represents an integer of 0 to 4. * represents a bonding site with other sites. )

[0037] <15> A wound body comprising a core material and the multilayer body according to any one of <1> to <13> wound around the core material.

[0038] <16> A wound body as described in <15>, wherein the resin-containing layer having an arithmetic mean waviness Wa of 0.03 to 0.35 μm is wound on a side farther from the core material, and the corrugations do not include corrugations having a width less than 500 μm and greater than 3000 μm.

[0039] <17> A winding body as described in <15> or <16>, wherein the resin-containing layer having an arithmetic mean waviness Wa of 0.03 to 0.30 μm is wound on a side farther from the core material, and the above-mentioned corrugations do not include corrugations having a width less than 500 μm and greater than 3000 μm.

[0040] Effects of the Invention

[0041] According to the present invention, a multilayer body can be provided, wherein a protective film including an adhesive layer is provided on the surface of a thin polycarbonate film, and when the protective film is peeled off, orange peel is less likely to occur on the surface of the polycarbonate film. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram showing a layer structure of an example of a multilayer body according to the present embodiment.

[0043] Figure 2 This is a schematic diagram for explaining the difference between the waviness and roughness of a film. DETAILED DESCRIPTION

[0044] Hereinafter, an embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail. However, the following this embodiment is only an example for explaining the present invention, and the present invention is not limited to this embodiment.

[0045] In the present specification, the use of "to" means that the numerical values ​​described before and after it are included as the lower limit and the upper limit.

[0046] In this specification, various physical property values ​​and characteristic values ​​are values ​​at 23°C unless otherwise specified.

[0047] The multilayer body in this specification is intended to include an object having a film or sheet shape. "Film" and "sheet" refer to a generally flat shaped body whose thickness is thinner than its length and width, respectively. In addition, "film" and "sheet" in this specification may be a single layer or a multilayer.

[0048] When the measurement methods and the like described in the standards shown in this specification differ by year, unless otherwise specified, the standards as of January 1, 2022 are used.

[0049] The multilayer body of the present embodiment is characterized in that the multilayer body comprises a polycarbonate film having a thickness of 20 to 75 μm and a protective film arranged on at least one surface of the polycarbonate film, the protective film comprising an adhesive layer capable of being peeled off from the polycarbonate film and a layer containing a resin, the adhesive layer is in contact with the polycarbonate film, and when the polycarbonate film is peeled off from the multilayer body, the arithmetic mean waviness Ma of the adhesive layer excluding the concavities and convexities with a corrugation width of less than 500 μm and greater than 3000 μm is 0 to 0.12 μm.

[0050] In the present embodiment, by setting Ma of the adhesive layer to be within the above range, it is possible to effectively suppress the generation of orange peel on the surface of the polycarbonate film when the protective film is peeled off.

[0051] The inventors of the present invention have conducted research and found that the thinness of the polycarbonate film is the cause of the orange peel texture. Figure 1 Provide explanation. Figure 1 1 is a schematic diagram showing the layer structure of an example of a multilayer body of the present embodiment, 1 represents the multilayer body, 2 represents the polycarbonate film, 3 represents the protective film, 4 represents the adhesive layer, and 5 represents the layer containing the resin (hereinafter sometimes referred to as the "resin layer"). That is, the protective film 3 has the adhesive layer 4 that can be peeled off from the polycarbonate film 2, and the resin layer 5. The scale of each layer is not necessarily the same. Figure 1 In the manner shown, when a polycarbonate film 2 is used, Figure 1 The interface of the arrow shown peels off the protective film 3. In addition, in this embodiment, a layer other than these layers may be included.

[0052] exist Figure 1 In the multilayer body shown, the resin layer 5 is the outermost layer, and in order to impart slidability to the multilayer body, the surface of the outermost layer is usually given roughness (concavity and convexity).

[0053] Before laminating the protective film 3 with the polycarbonate film 2, the protective film 3 is wound around the core material so that the adhesive layer 4 and the resin layer 5 are in contact. At this time, the unevenness of the resin layer 5 is transferred to the adhesive layer 4. It is found that when the thickness of the polycarbonate film 2 is thin, when the polycarbonate film 2 and the protective film 3 are attached, the unevenness of the adhesive layer 4 sometimes follows the polycarbonate film 2, resulting in orange peel. It is also found that even when wound around the core material, the unevenness of the adhesive layer 4 is sometimes printed on the polycarbonate film 2.

[0054] It was further found that even if orange peel does not occur immediately after the polycarbonate film 2 and the protective film 3 are bonded together, orange peel may occur over time. That is, the adhesive layer 4 is usually soft, so the effect is small immediately after the polycarbonate film 2 and the protective film 3 are bonded together. However, due to the creep phenomenon of the thin polycarbonate film 2, orange peel is likely to occur over time. It was also found that orange peel is likely to occur due to the storage conditions of the multilayer body. In particular, it was found that orange peel is likely to occur when the multilayer body is stored at a relatively high temperature.

[0055] On the other hand, it was found that the problem of orange peel is particularly unlikely to occur when the thickness of the polycarbonate film is greater than a certain value. The reason for this is presumably that when the thickness of the polycarbonate film is thick, the rigidity becomes high, and thus the above-mentioned influence is unlikely to occur.

[0056] Under such circumstances, the inventors of the present invention conducted research and found that the waviness of the adhesive layer affects the orange peel texture. That is, it was found that the generation of orange peel texture on the surface of the polycarbonate film 2 can be effectively suppressed by adjusting the arithmetic average waviness Ma of the surface of the adhesive layer 4 when the polycarbonate film 2 is peeled off from the multilayer body 1, especially the arithmetic average waviness Ma of the concavities and convexities excluding the corrugations with a corrugation width of less than 500 μm and greater than 3000 μm. The reason for this is presumably that the orange peel texture is mainly the concavities and convexities that can be confirmed by visual observation, such as large corrugations and / or small concavities and convexities as shown in Ra, and small corrugations.

[0057] Hereinafter, the present invention will be described in detail.

[0058] <Polycarbonate film with a thickness of 20 to 75 μm>

[0059] The polycarbonate film used in this embodiment is a film with a thickness of 20 to 75 μm. When a thin polycarbonate film of such a thickness is used, due to various reasons and conditions, after the polycarbonate film and the protective film having an adhesive layer and a resin layer are attached to each other on the adhesive layer side, orange peel lines can be seen when the protective film is peeled off. In this embodiment, even if a thin polycarbonate film is used, this can be avoided, which is beneficial in this respect.

[0060] The thickness of the polycarbonate film is preferably 25 μm or more, more preferably 30 μm or more, further preferably 35 μm or more, further preferably 40 μm or more, and further preferably 45 μm or more. By being above the lower limit, the winding property of the multilayer body tends to be further improved. In addition, the thickness of the polycarbonate film is preferably 70 μm or less, more preferably less than 67 μm, further preferably 65 μm or less, further preferably 60 μm or less, and further preferably 55 μm or less. By being below the upper limit, the thermoformability tends to be improved.

[0061] The thickness of the polycarbonate film in this embodiment refers to the average thickness at any five points. In addition, the thickness of the polycarbonate film in this embodiment is preferably within ±20% of the average thickness in the entire region, more preferably within ±10% of the average thickness, and further preferably within ±5% of the average thickness. The same applies to other thicknesses such as the thickness of the adhesive layer.

[0062] The polycarbonate film used in the present embodiment contains polycarbonate. In the present embodiment, the polycarbonate is preferably a bisphenol polycarbonate, and more preferably a bisphenol A polycarbonate.

[0063] Bisphenol A polycarbonate may also have other structural units other than carbonate structural units derived from bisphenol A and its derivatives. As dihydroxy compounds constituting such other structural units, for example, aromatic dihydroxy compounds described in paragraph 0014 of Japanese Patent Publication No. 2018-154819 can be cited, and these contents are introduced into this specification.

[0064] In the bisphenol polycarbonate of the present embodiment, the carbonate structural units derived from bisphenol A and its derivatives preferably account for 90% by mass or more of all structural units excluding terminal structures, more preferably 95% by mass or more, and further preferably 97% by mass or more.

[0065] The method for producing bisphenol A polycarbonate is not particularly limited, and any method may be used, and examples thereof include interfacial polymerization, melt transesterification, pyridine method, ring-opening polymerization of cyclic carbonate compounds, and solid phase transesterification of prepolymers.

[0066] In the present embodiment, the polycarbonate film preferably contains a polycarbonate having a terminal structure represented by formula (1).

[0067]

[0068] (In formula (1), R 1 R represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms. 2 Each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 6 to 12 carbon atoms. n represents an integer of 0 to 4. * represents a bonding site with another site. )

[0069] R 1 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms, preferably an alkyl group or alkenyl group having 10 or more carbon atoms, more preferably an alkyl group or alkenyl group having 12 or more carbon atoms, and further preferably an alkyl group or alkenyl group having 14 or more carbon atoms. This can lower the glass transition temperature of the resin and improve the thermal bendability of the multilayer body. 1An alkyl group or alkenyl group having 22 or less carbon atoms is preferred, and an alkyl group or alkenyl group having 18 or less carbon atoms is more preferred. This tends to improve compatibility with other resins. 1 The alkyl group and the alkenyl group are preferably linear or branched alkyl groups or alkenyl groups, and more preferably linear alkyl groups or alkenyl groups.

[0070] In this embodiment, R 1 Hexadecyl is particularly preferred.

[0071] In addition, R 1 It may be located at any position among the meta, para and ortho positions, preferably at the meta or para position, and more preferably at the para position.

[0072] R 2 Each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and is preferably a fluorine atom, a chlorine atom, a methyl group, an ethyl group, or a phenyl group, and more preferably a fluorine atom, a chlorine atom, or a methyl group.

[0073] n represents an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1, and further preferably 0.

[0074] The terminal structure represented by formula (1) can be added to the polycarbonate by using a terminal blocking agent such as hexadecyl p-hydroxybenzoate. For details of these, reference can be made to paragraphs 0022 to 0030 of Japanese Patent Application Laid-Open No. 2019-002023, which are incorporated into this specification.

[0075] In the polycarbonate having a terminal structure represented by the formula (1) used in the present embodiment, the terminal structure represented by the formula (1) may be one type or two or more types.

[0076] In addition, in the polycarbonate having the terminal structure represented by formula (1) used in the present embodiment, sometimes not all terminal structures are terminal structures represented by formula (1). Generally, more than 80% (preferably more than 90%) of the terminal structures of the polycarbonate used in the present embodiment are terminal structures represented by formula (1).

[0077] In this embodiment, the polycarbonate having a terminal structure represented by formula (1) is preferably a bisphenol polycarbonate, more preferably a bisphenol A polycarbonate. In addition, preferably, 50% by mass or more of the bisphenol polycarbonate has at least one terminal structure represented by formula (1).

[0078] Bisphenol A polycarbonate may also have other structural units other than carbonate structural units derived from bisphenol A and its derivatives. As dihydroxy compounds constituting such other structural units, for example, aromatic dihydroxy compounds described in paragraph 0014 of Japanese Patent Publication No. 2018-154819 can be cited, and the contents of these are introduced into this specification.

[0079] In the bisphenol polycarbonate of the present embodiment, the carbonate structural units derived from bisphenol A and its derivatives preferably account for 90% by mass or more of all structural units excluding terminal structures, more preferably 95% by mass or more, and further preferably 97% by mass or more.

[0080] The viscosity average molecular weight of the polycarbonate used in this embodiment is preferably 17,000 to 40,000. When the viscosity average molecular weight is 17,000 or more, the bending resistance can be enhanced, and a multilayer body with excellent bending resistance can be obtained. In addition, when the viscosity average molecular weight is 40,000 or less, the effect of suppressing the increase of torque during extrusion molding tends to be further improved by being below the above upper limit.

[0081] The viscosity average molecular weight of the polycarbonate is more preferably 20,000 or more, further preferably 22,000 or more, and further preferably 24,000 or more. In addition, the viscosity average molecular weight of the polycarbonate is more preferably 38,000 or less, and further may be 35,000 or less, particularly may be less than 30,000, and more particularly may be 28,000 or less. In particular, by making the viscosity average molecular weight less than 30,000, and further 28,000 or less, the viscosity of the polycarbonate becomes lower, and there is a tendency that the filter permeability is improved. When the filter permeability is improved, foreign matter in the membrane can be reduced.

[0082] The viscosity average molecular weight of the polycarbonate can be measured by the method described in the examples described later.

[0083] The glass transition temperature (Tg) of the polycarbonate used in the present embodiment is preferably 155°C or less, more preferably 152°C or less, further preferably 142°C or less, further preferably 138°C or less, and further preferably 132°C or less. By being below the above upper limit, there is a tendency that the heat bending formability of the multilayer body is further improved. In addition, the glass transition temperature (Tg) of the polycarbonate used in the present embodiment is preferably 115°C or more, more preferably 122°C or more, and further preferably 126°C or more. By being above the above lower limit, there is a tendency that the durability in environmental resistance tests such as a wet heat test and a high temperature test is further improved.

[0084] The glass transition temperature (Tg) is measured according to the description in the examples described below.

[0085] The polycarbonate film used in the present embodiment preferably contains polycarbonate in a ratio of 90% by mass or more of the film, more preferably 95% by mass or more, further preferably 98% by mass or more, and may be 100% by mass or less.

[0086] The polycarbonate film used in the present embodiment may also contain other components other than polycarbonate. As other components, heat stabilizers, antioxidants, flame retardants, flame retardant aids, ultraviolet absorbers, mold release agents, colorants, antistatic agents, near infrared shielding agents, light diffusing agents, fluorescent whitening agents, antifogging agents, flowability improvers, plasticizers, dispersants, antibacterial agents, etc. can be listed. Their total amount is preferably 0 to 10% by mass in the polycarbonate film, more preferably 0 to 5% by mass, and further preferably 0 to 2% by mass.

[0087] In order to release the residual stress during film forming, the polycarbonate film used in this embodiment can be annealed before lamination with the protective film. The annealing method is not particularly limited, and a known method can be used. By laminating the annealed polycarbonate film, warping and peeling in the heating process after lamination can be effectively suppressed.

[0088] <Protective film>

[0089] The multilayer body of the present embodiment includes a protective film disposed on at least one surface of the polycarbonate film. The protective film may be disposed on one surface of the polycarbonate film or on both surfaces. In the present embodiment, the protective film is preferably disposed on both surfaces of the polycarbonate film. When protective films are disposed on both surfaces of the polycarbonate film, the respective protective films may be the same or different.

[0090] The protective film has an adhesive layer that can be peeled from the polycarbonate film and a resin layer. These layers will be described below.

[0091] <<Adhesive layer>>

[0092] The multilayer body of the present embodiment has an adhesive layer that can be peeled from the polycarbonate film. The adhesive layer is usually provided in contact with the polycarbonate film and can be peeled from the polycarbonate film.

[0093] In the present embodiment, when the polycarbonate film is peeled off from the multilayer body, the arithmetic mean waviness Ma of the waviness of the adhesive layer is 0 to 0.12 μm, and the waviness does not include waviness with a waviness width of less than 500 μm and greater than 3000 μm. By adopting such a structure, a multilayer body having a protective film including an adhesive layer on the surface of a thin polycarbonate film can be produced, and when the protective film is peeled off, the multilayer body is not prone to produce orange peel on the surface of the polycarbonate film. The arithmetic mean waviness Ma refers to the average value of the absolute value of the waviness relative to the average surface. As the arithmetic mean waviness, the arithmetic mean waviness Wa is known, which is the average value of the absolute value of the waviness relative to the average line, and is different from the waviness relative to the average surface. Here, refer to Figure 2 The waviness will be described. Figure 2 This is a schematic diagram to illustrate the difference between the waviness and roughness of the film, and the dimensions are not necessarily accurate. Figure 2 In the figure, 20 represents the surface irregularities when observed from the cross section of the film. The irregularities 20 of the film are roughly divided into a roughness curve 21 and a waviness curve 22. The roughness curve 21 represents fine surface irregularities, while the waviness curve 22 represents large irregularities. In the present embodiment, it is found that it is not the roughness curve 21 of the adhesive layer peeled off from the polycarbonate film, but the waviness curve 22 that becomes a specified value, thereby effectively suppressing the generation of orange peel lines. In particular, the inventors of the present invention conducted research and found that by using a Gaussian filter to separate the corrugations with a width of less than 500μm and greater than 3000μm, and adjusting the obtained arithmetic mean waviness Ma (hereinafter sometimes referred to as "arithmetic mean waviness Ma") to a specified range, the generation of orange peel lines can be suppressed. Among them, the corrugation width refers to the width of the convex portion relative to the corrugation reference plane, for example, refers to Figure 2 The length between the arrows shown by symbol 23 in FIG.

[0094] That is, in a multilayer body having a protective film provided on at least one surface of a polycarbonate film, when the thickness of the polycarbonate film is thin, the concavoconvexity of the outermost layer may follow the polycarbonate film and produce orange peel texture due to the conditions when the layers are stacked and laminated by rollers (e.g., the pressure of the rollers during lamination). In the present embodiment, the above technical problem is solved by making the arithmetic mean waviness of the adhesive layer when the polycarbonate film is peeled off within a predetermined range.

[0095] The arithmetic mean waviness Ma of the waviness of the adhesive layer when the polycarbonate film is peeled off is 0.12 μm or less, preferably 0.11 μm or less, more preferably 0.09 μm or less, further preferably 0.07 μm or less, and further preferably 0.06 μm or less, wherein the waviness does not include waviness with a waviness width of less than 500 μm and greater than 3000 μm. By being below the above upper limit, there is a tendency that the effect of suppressing the generation of orange peel lines is further improved. The arithmetic mean waviness Ma is 0 μm or more, preferably 0.01 μm or more, more preferably 0.02 μm or more, further preferably 0.03 μm or more, and further preferably 0.04 μm or more. By being above the above lower limit, there is a tendency that the sliding property of the multilayer body is further improved.

[0096] Such an arithmetic mean waviness Ma can be achieved, for example, by increasing the arithmetic mean waviness Wa of the waviness of the multilayer body, wherein the waviness of the multilayer body does not include wavinesses having a waviness width of less than 500 μm and greater than 3000 μm.

[0097] The arithmetic mean waviness Ma is measured according to the description in the examples described later.

[0098] The material of the adhesive layer is not particularly limited as long as it can be peeled from the polycarbonate film, and a known adhesive layer can be used.

[0099] The type of the adhesive is not particularly limited, but it is preferred that the adhesive contain at least one of a polyolefin adhesive, an acrylic adhesive, a silicone adhesive, and a polyurethane adhesive.

[0100] Examples of the polyolefin adhesive include polypropylene-based adhesives (homopolypropylene, random or block copolymers of ethylene and propylene, and ternary copolymers of ethylene, butene, and propylene).

[0101] The polyolefin adhesive is an adhesive containing a polyolefin-based resin, and specific examples thereof include NOVATEC (LC522) which is a low-density polyethylene manufactured by Japan Polyethylene Co., Ltd. and Ultrasen (750) which is an ethylene-vinyl acetate copolymer manufactured by Tosoh Corporation.

[0102] Acrylic adhesives are adhesives containing acrylic polymers. Specific examples include Finetac (CT-3088, CT-3850, CT-6030, CT-5020, CT-5030) manufactured by DIC Corporation, QUICK MASTER (SPS-900-IV, QUICK MASTER SPS-1040NT-25), and the adhesive Oribain manufactured by TOYOCHEM Corporation.

[0103] The silicone adhesive is an adhesive containing a silicone-based polymer, and specific examples thereof include polymers produced by KR-3704 (main agent) and CAT-PL-50T (platinum catalyst) manufactured by Shin-Etsu Chemical Co., Ltd., and the like.

[0104] The polyurethane adhesive is an adhesive containing a polyurethane-based polymer, and specific examples thereof include an adhesive called Oribain manufactured by TOYOCHEM.

[0105] In the present specification, a polymer refers to a compound having a number average molecular weight of 1,000 or more, preferably 2,000 or more.

[0106] As the adhesive layer, in addition to the above-mentioned adhesive layer, the adhesive layer described in paragraphs 0026 to 00053 of Japanese Patent Application Publication No. 2017-200975, the adhesive layer described in paragraphs 0056 to 0060 of Japanese Patent Application Publication No. 2013-020130, the adhesive sheet of International Publication No. 2016 / 158827, and the adhesive layer described in Japanese Patent Application Publication No. 2016-1827 can be used without departing from the gist of the present invention. The adhesive layer of paragraphs 0031 to 0032 of Japanese Patent Publication No. 91, the rubber-based adhesive layer of paragraphs 0057 to 0084 of Japanese Patent Publication No. 2015-147837, the adhesive layer described in paragraphs 0024 and 0026 of Japanese Patent Publication No. 2019-178273, and the adhesive layer described in paragraphs 0027 to 0032 of Japanese Patent Publication No. 2018-145365 are incorporated into this specification.

[0107] The thickness of the adhesive layer is not particularly limited, but is preferably 1 μm or more and preferably 70 μm or less. Within the above range, more suitable adhesive properties and adhesive strength can be achieved.

[0108] Next, the peeling force of the adhesive layer will be described.

[0109] In the present invention, after the polycarbonate film and the protective film are bonded together, in a peel test in accordance with JIS Z0237 at 152 mm / min in a 180° direction, it is preferred that a peel force of 0.001 to 4.5 N / 25 mm be exhibited.

[0110] The peeling force can be controlled by the composition of the adhesive layer. For example, in the case of an organosilicon-based adhesive layer, the peeling force can be adjusted by the main chain structure, terminal structure, branched structure and molecular weight of the polyorganosiloxane formed. In addition, in the case of a polyurethane-based adhesive layer, the peeling force can be adjusted by the main chain structure and molecular weight of the polyol and polyisocyanate formed, and their ratio. In addition, in the case of an acrylic-based adhesive layer, the peeling force can be adjusted by the monomer structure and molecular weight of the acrylic resin formed, the copolymerization ratio, the main chain structure and molecular weight of the polyisocyanate, and the ratio of the acrylic resin to the polyisocyanate.

[0111] Furthermore, by combining adhesives having different adhesive strengths, it is also possible to form an adhesive layer having any peeling strength.

[0112] <<Layer containing resin (resin layer)>>

[0113] The protective film has an adhesive layer and a resin layer that can be peeled off from the polycarbonate film. The adhesive layer is usually provided in contact with the polycarbonate film and can be peeled off from the polycarbonate film. The resin layer is usually a layer forming a substrate of the protective film.

[0114] The resin constituting the resin layer is preferably a thermoplastic resin, more preferably a polyolefin resin and / or a polyester resin. The polyolefin resin is preferably a cycloolefin resin, a polyethylene resin, or a polypropylene resin. The polyester resin is preferably a polyethylene terephthalate resin.

[0115] The ratio of the resin (preferably a thermoplastic resin) in the resin layer is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 98% by mass or more.

[0116] The resin layer may also contain ingredients other than the resin. Specifically, heat stabilizers, antioxidants, flame retardants, flame retardant aids, ultraviolet absorbers, mold release agents, colorants, antistatic agents, near infrared shielding agents, light diffusers, fluorescent whitening agents, antifogging agents, fluidity improvers, plasticizers, dispersants, antibacterial agents, etc. may be mentioned. The total amount of these in the resin layer is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and further preferably 0 to 2% by mass.

[0117] The resin layer in this embodiment preferably has a surface point defect number of 2000 / m 2 Such surface point defects can be achieved by reducing the retention time during molding or using a polymer filter. The number of the above-mentioned surface point defects is more preferably 1000 / m 2 Below, more preferably 500 pieces / m 2 Below, more preferably 250 pieces / m 2Below, more preferably 100 pieces / m 2 By setting the above upper limit value or less, the point defects of the polycarbonate film can also be reduced. The lower limit value of the number of point defects on the surface is 0 pieces / m 2 It is ideal, but in reality it is 1 / m 2 above.

[0118] The number of point defects on the surface can be measured according to the description in the examples described later.

[0119] In the present embodiment, in addition, the arithmetic mean waviness Wa of the corrugations of the layer on the outermost side of the resin layer is preferably 0.03 μm to 0.35 μm (preferably 0.30 μm or less), and the corrugations do not include corrugations with a corrugation width of less than 500 μm and greater than 3000 μm. In the case where the protective film includes more than two resin layers, the layer on the outermost side refers to the layer present on the outermost side. In addition, in the case where the protective film is provided on both surfaces of the multilayer body, it refers to the value of the larger arithmetic mean waviness Wa. In the case where the arithmetic mean waviness Wa refers to the average value of the corrugation height relative to the average line.

[0120] When at least one of the outermost layers satisfies the arithmetic mean waviness Wa, a layer having sliding properties can be formed. An example of an outermost layer having sliding properties is a layer containing particles. Examples of the particles include acrylic particles, styrene particles, and silica particles. In addition, the proportion of the particles in the resin layer is preferably 0.01 to 20% by mass.

[0121] It is also effective to mix incompatible resins in the resin layer. As an example, low-density polyethylene is mixed with a polypropylene resin.

[0122] The arithmetic mean waviness Wa of the resin layer (preferably the outermost layer) is preferably 0.03 μm or more, more preferably 0.05 μm or more, and further can be 0.10 μm or more, 0.15 μm or more. By being above the above lower limit, there is a tendency for the sliding property to be further improved. The arithmetic mean waviness Wa of the resin layer (preferably the outermost layer) is preferably 0.35 μm or less, more preferably 0.30 μm or less, further preferably 0.25 μm or less, and further preferably 0.18 μm or less. By being below the above upper limit, there is a tendency for the effect of suppressing the increase of the arithmetic mean waviness Ma of the adhesive layer to be further improved.

[0123] Such an arithmetic mean waviness Wa can be achieved by adjusting the amount of fine particles added and the mixing ratio of the incompatible resins in the resin layer.

[0124] The arithmetic mean waviness Wa can be measured according to the description in the examples described later.

[0125] <<Other layers>>

[0126] The protective film in this embodiment may also include layers other than the resin layer and the adhesive layer. Specifically, a primer layer, a hard coat layer, an anti-adhesion layer, and a layer containing particles may be exemplified. As a layer containing particles, a layer in which inorganic particles are combined in a resin layer may be exemplified.

[0127] In order to release the residual stress during film molding, the protective film used in this embodiment can be annealed before lamination with the polycarbonate film. The annealing method is not particularly limited, and a known method can be used. By laminating the annealed protective film, warping and peeling in the heating process after lamination can be effectively suppressed.

[0128] The thickness of the protective film used in the present embodiment is preferably 90 μm or less, more preferably 60 μm or less, more preferably 40 μm or less, and more preferably 35 μm or less, and is preferably 10 μm or more, more preferably 20 μm or more, and more preferably 25 μm or more. In addition, by being below the above upper limit, the generation of orange peel on the polycarbonate film can be effectively suppressed.

[0129] Regarding the multilayer body in the present embodiment, the total thickness of the adhesive layer and the resin layer is preferably 90 μm or less, more preferably 60 μm or less, more preferably 40 μm or less, and more preferably 35 μm or less, and is preferably 10 μm or more, more preferably 20 μm or more, and more preferably 25 μm or more. In addition, by being below the above upper limit, the generation of orange peel on the polycarbonate film can be effectively suppressed.

[0130] <Layer structure of multilayer body>

[0131] Next, the layer structure of the multilayer body according to the present embodiment will be described.

[0132] The multilayer body of the present embodiment includes a polycarbonate film and a protective film provided on at least one surface of the polycarbonate film.

[0133] An example of a preferred multilayer body of this embodiment is the above-mentioned Figure 1 That is, the protective films 3 are provided on both sides of the polycarbonate film 2. In addition, when the protective films are provided on both sides, it is sufficient that the arithmetic mean waviness Ma of the adhesive layer when the polycarbonate film is peeled off from at least one side satisfies the prescribed range.

[0134] The first embodiment of the multilayer body of the present embodiment is a mode in which a protective film is respectively included on both sides of the polycarbonate film and the resin layer respectively contains a polyolefin resin. By becoming such a mode, warping can be reduced, and stress during a heated tensile test can be reduced. In the present embodiment, each film containing a polyolefin resin can be the same film or different films, preferably the same film. In the present embodiment, the amount of the polyolefin resin contained in the resin layer is respectively more than 90% by mass, more preferably more than 95% by mass, and further preferably more than 98% by mass.

[0135] The second embodiment of the multilayer body of the present embodiment preferably includes protective films on both sides of the polycarbonate film, the resin layer on one side of the polycarbonate film contains a polyolefin resin, and the resin layer on the other side of the polycarbonate film contains a polyester resin. By forming such a structure, the occurrence of roll bulges can be effectively suppressed when rolled on a core material, and by peeling off the protective film composed of a resin layer containing polyester, the stress during the heating tensile test can be reduced. In this embodiment, the amount of polyolefin resin contained in one resin layer is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 98% by mass or more. In addition, the amount of polyester resin contained in another resin layer is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 98% by mass or more.

[0136] The third embodiment of the multilayer body of the present embodiment is a mode in which a protective film is respectively included on both sides of the polycarbonate film and the resin layers respectively contain polyester resins. By adopting such a mode, the warping of the obtained multilayer body can be effectively suppressed. The haze of the obtained multilayer body can also be reduced. In the present embodiment, each film containing polyester resin can be the same film or different films, preferably the same film. In the present embodiment, the amount of polyester resin contained in the resin layer is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 98% by mass or more.

[0137] The multilayer body of the present embodiment may include other constituent layers in addition to the above-mentioned layers. Examples of other constituent layers include an anti-adhesion layer and a layer containing microparticles. These are usually provided on the outside of the protective layer.

[0138] The multilayer body of the present embodiment can be produced by laminating the protective films so that the adhesive layer side of the protective film contacts the polycarbonate film and bonding them with a roller or the like.

[0139] In addition, as described above, the polycarbonate film and / or the protective film may be subjected to an annealing treatment before lamination. By performing the annealing treatment, warping and interlayer peeling in the heating step after lamination can be effectively suppressed.

[0140] <Physical properties of multilayer bodies>

[0141] Next, various physical properties of the multilayer body of the present embodiment will be described.

[0142] The multilayer body of the present embodiment preferably satisfies any one of the following conditions (1) and (2).

[0143] (1) The tensile elastic modulus of the multilayer body is 1800 MPa or more;

[0144] (2) The tensile elastic modulus of the multilayer body is less than 1800 MPa, and the arithmetic mean waviness Wa of the corrugations of the resin layer is 0.15 μm or more, excluding corrugations having a corrugation width of less than 500 μm and more than 3000 μm.

[0145] By adopting such a configuration, the occurrence of curl bulge can be effectively suppressed.

[0146] As a method for realizing the multilayer body of the above (1), at least one resin layer may be made of a polyester film. In the above (1), the tensile modulus is preferably 3000 MPa or less.

[0147] As a method for realizing the multilayer body of (2) above, a polyolefin film having an arithmetic mean waviness Wa of the resin layer that satisfies the range of (2) above can be cited. In (2) above, the tensile elastic modulus is preferably 1000 MPa or more. In addition, the arithmetic mean waviness Wa is 0.35 μm or less (preferably 0.30 μm or less).

[0148] The multilayer body of the present embodiment is not particularly limited when used for purposes that do not require transparency. On the other hand, the haze of the multilayer body of the present embodiment is preferably 50% or less, more preferably 30% or less, further preferably 25% or less, further preferably 20% or less, further more preferably 18% or less, and particularly preferably 10% or less. The lower limit of the above haze is actually 1% or more. As a method for achieving such low haze, adjustment of the amount of microparticles added or the mixing ratio of incompatible resins in the resin layer can be cited.

[0149] The tensile modulus of the multilayer body of the present embodiment may be, for example, 1000 MPa or more, more preferably 1100 MPa or more, and further may be 1400 MPa or more, 1800 MPa or more. The tensile modulus of the multilayer body of the present embodiment is also preferably 3000 MPa or less, and may be less than 1800 MPa based on the value of the arithmetic mean waviness Wa, etc. As a method for increasing the tensile modulus, a protective film containing polyester may be used in the resin layer. As a method for reducing the tensile modulus, a protective film containing polyolefin may be used in the resin layer.

[0150] The tensile modulus is measured as described in Examples below.

[0151] The wound body of the present embodiment comprises a core material and the multilayer body of the present embodiment wound around the core material. Such a wound body can effectively suppress the generation of orange peel on the polycarbonate film even when the protective film is peeled off.

[0152] In the present embodiment, the resin layer having an arithmetic mean waviness Wa of 0.03 μm to 0.35 μm (preferably 0.30 μm or less) is preferably wound in a manner that is farther from the core material, wherein the waviness does not include waviness having a width of less than 500 μm and greater than 3000 μm. By forming such a structure, it is possible to effectively suppress the generation of orange peel on the polycarbonate film due to the unevenness of the layer (outside) from the back side when the multilayer body is wound.

[0153] The thickness of the multilayer body of the present embodiment is not particularly limited, and is, for example, 60 μm or more and, for example, 400 μm or less.

[0154] The multilayer body and wound body of the present embodiment can be used in the form of a polycarbonate film (particularly a single-layer polycarbonate film) after peeling off the protective film. In addition, the multilayer body of the present embodiment may also include other layers, and as other layers, known layers can be used, and examples thereof include an adhesive layer and a hard coating layer, preferably including an adhesive layer. Of course, both an adhesive layer and a hard coating layer may also be included.

[0155] As the adhesive layer, a polyolefin resin layer can be exemplified.

[0156] As the hard coat layer, reference may be made to paragraphs 0045 to 0055 of Japanese Patent Application Laid-Open No. 2013-020130, paragraphs 0073 to 0076 of Japanese Patent Application Laid-Open No. 2018-103518, and paragraphs 0062 to 0082 of Japanese Patent Application Laid-Open No. 2017-213771, and these contents are incorporated into this specification.

[0157] The polycarbonate film is preferably used as a protective film or substrate of the transparent conductive film. In particular, it is preferably used in the form of a transparent conductive film having a protective layer, an adhesive layer, a substrate and an electrode layer in this order, and at least one of the substrate and the protective layer (preferably at least the protective layer) is a polycarbonate film.

[0158] Furthermore, the transparent conductive film is preferably used as a transparent conductive film for a film sensor for a touch panel, electronic paper, a dye-sensitized solar cell, a touch sensor, or the like.

[0159] In addition to the above, the polycarbonate film is also preferably used as a film for applications requiring high transparency, for example, as an anti-splash film.

[0160] Example

[0161] Below, enumerate embodiment and the present invention is described more specifically.As long as do not depart from the gist of the present invention, the material shown in the following embodiment, usage, ratio, processing content, processing step etc. can be appropriately changed.Therefore, the scope of the present invention is not limited to the specific example shown below.

[0162] When the measuring equipment used in the examples is difficult to obtain due to discontinuation of production, other equipment with equivalent performance may be used for measurement.

[0163] 1. Raw materials

[0164] As the polycarbonate film, the following films were used.

[0165] <Manufacturing of polycarbonate film 1>

[0166] Bisphenol A polycarbonate flakes (E-2000F manufactured by Mitsubishi Engineering-Plastics Corporation, viscosity average molecular weight 27,000, Tg: 150°C) and bisphenol A polycarbonate flakes (S-3000F manufactured by Mitsubishi Engineering-Plastics Corporation, viscosity average molecular weight 21,000, Tg: 146°C) were dry-blended so that the mass ratio became 1:1, mixed in a tumbler for 15 minutes, and then melt-kneaded at a barrel temperature of 280°C using a twin-screw extruder with a screw diameter of 32 mm ("TEX30α" manufactured by The Japan Steel Works, Ltd.), and pellets were obtained using a strand cutter.

[0167] <Film production>

[0168] Using the pellets obtained above, a film was produced by the following method.

[0169] The pellets were extruded in a molten state using a T-die melt extruder (manufactured by Japan Steel Works, Ltd., "TEX30α") ​​with a barrel diameter of 32 mm and a screw L / D of 31.5, at a discharge rate of 10 kg / h and a screw speed of 150 rpm, and then cooled and solidified to produce a film. The barrel and T-die temperatures were set to 280°C.

[0170] The rolling speeds of the first roll and the second roll were changed to adjust the thickness (unit: μm) of the film finally obtained to 50 μm.

[0171] The details of the first roll and the second roll used are as follows.

[0172] · First roller: Silicone rubber roller (IT68S-MCG) manufactured by Mochida Shoko Co., Ltd.

[0173] Size: outer diameter 260mm x width 600mm

[0174] Roller temperature: 50°C

[0175] · Second roller: Mirror metal rigid roller (surface: hard chrome treatment)

[0176] Core mold size: outer diameter 250mm×width 600mm

[0177] Roller temperature: 120℃

[0178] <Manufacturing of polycarbonate film 2>

[0179] <<Synthesis Example of PC-1>>

[0180] According to the description of Handbook of Organic Chemistry P143-150, 4-hydroxybenzoic acid produced by Tokyo Chemical Industry Co., Ltd. and 1-hexadecanol produced by Tokyo Chemical Industry Co., Ltd. were used to carry out esterification by dehydration reaction to obtain cetyl p-hydroxybenzoate (CEPB).

[0181] 7.1 kg (31.14 mol) of bisphenol A (BPA) manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd. and 30 g of sodium dithionite (Hydrosulfite) were added to 57.2 kg of 9 mass % aqueous sodium hydroxide solution and dissolved. 40 kg of dichloromethane was added thereto, and 4.33 kg of phosgene was blown in over 30 minutes while stirring the solution while keeping the solution temperature at 15 to 25°C.

[0182] After the phosgene blowing was completed, 6 kg of a 9 mass % aqueous sodium hydroxide solution, 11 kg of dichloromethane, and a solution prepared by dissolving 443 g (1.22 mol) of the CEPB obtained above in 10 kg of dichloromethane were added, and the mixture was vigorously stirred to emulsify. Then, 10 mL of triethylamine was added as a polymerization catalyst, and polymerization was carried out for about 40 minutes.

[0183] The polymer solution was separated into an aqueous phase and an organic phase, and the organic phase was neutralized with phosphoric acid and repeatedly washed with pure water until the pH of the washing liquid became neutral. The organic solvent was distilled off from the purified aromatic polycarbonate solution to obtain an aromatic polycarbonate powder (PC-1).

[0184] The viscosity average molecular weight (Mv) and glass transition temperature (Tg) of the obtained aromatic polycarbonate powder were measured. The viscosity average molecular weight was 25,500 and the Tg was 130°C.

[0185] <<Film production>>

[0186] In the above-mentioned <Production of Polycarbonate Film 1>, the type of polycarbonate was changed to the polycarbonate synthesized in the above-mentioned <<Synthesis Example of PC-1>>, and the other procedures were carried out in the same manner.

[0187] <Manufacturing of polycarbonate film 3>

[0188] The thickness of the polycarbonate film 1 was adjusted to 100 μm, and the other parts were carried out in the same manner.

[0189] <Measurement of viscosity average molecular weight (Mv)>

[0190] The viscosity average molecular weight of the polycarbonate is measured by the following method.

[0191] Dichloromethane was used as the solvent, and the intrinsic viscosity [η] (unit: dL / g) at a temperature of 20°C was determined using an Ubbelohde viscometer. From the Schnell viscosity formula, η = 1.23 × 10 -4 Mv 0.83 In addition, the intrinsic viscosity [η] is the specific viscosity [η] at each solution concentration [C] (g / dL) sp ] and use the following formula to calculate the value.

[0192]

[0193] <Measurement of glass transition temperature (Tg)>

[0194] The glass transition temperature of polycarbonate is measured as follows.

[0195] For about 10 mg of polycarbonate (pellets), two cycles of heating and cooling were performed under the following DSC (differential scanning calorimetry) measurement conditions, and the glass transition temperature during the second cycle of heating was measured. The intersection of the straight line obtained by extending the baseline on the low temperature side to the high temperature side and the tangent line of the inflection point was taken as the starting glass transition temperature, the intersection of the straight line obtained by extending the baseline on the high temperature side to the low temperature side and the tangent line of the inflection point was taken as the ending glass transition temperature, and the midpoint between the starting glass transition temperature and the ending glass transition temperature was taken as the glass transition temperature (Tg, unit: ° C) of the present invention.

[0196] Measurement start temperature: 30°C

[0197] Heating rate: 10℃ / min

[0198] Reaching temperature: 250℃

[0199] Cooling speed: 20℃ / min

[0200] A differential scanning calorimeter (DSC, manufactured by Hitachi High-Technologies Corporation, “DSC7020”) was used as a measuring apparatus.

[0201] <Protective film>

[0202] As the protective film, the films shown in the following Table 1 were used. Each protective film has an adhesive layer and a resin layer, the outermost surface of one surface is the adhesive layer, and the outermost surface of the other surface is the resin layer. PET is the abbreviation of polyethylene terephthalate.

[0203] [Table 1]

[0204]

[0205] *1: The arithmetic mean waviness (Wa) of the waviness on the side of the resin layer opposite to the adhesive layer, excluding waviness with a waviness width of less than 500 μm and greater than 3000 μm.

[0206] The protective film 4 and the comparative protective film 1 have the same product number but different thicknesses.

[0207] <Arithmetic mean waviness Wa of resin layer [μm]>

[0208] The arithmetic mean waviness Wa of the surface of the resin layer of the protective film on the opposite side to the adhesive layer was measured as follows.

[0209] Wa was measured using a surface profile measuring machine in accordance with JIS B0601: 2001. The measurement conditions were reference length = 0.8 mm, number of sections = 5, λf = 3.0 mm, λc = 0.5 mm. The film flow direction was set as the measurement direction, and the average value of three measurements was calculated.

[0210] The surface shape measuring machine used was a contact type surface shape measuring machine CS-H5000CNC manufactured by Mitutoyo Corporation.

[0211] In Tables 2 and 3, the larger value Wa of the protective film a and the protective film b is represented as the arithmetic mean waviness Wa [unit: μm] of the protective film resin layer.

[0212] <Point defects in the resin layer>

[0213] The number of point defects (number of point defects) in the resin layer of the protective film was evaluated as follows.

[0214] For the protective film of 10cm×10cm, light was irradiated from the side surface of the resin layer at an angle of 20° to 70° so that the illumination on the film surface was 1000Lux, and the reflected light was visually observed to detect point defects. The defects were observed using an optical microscope manufactured by Nikon, and the number of defects with a major diameter of 100μm or more was counted. The average value of this was repeated 3 times, and the number of defects per 1m was calculated. 2 The number of .

[0215] <Haze of protective film>

[0216] The haze (unit: %) of the multilayer body was measured using a haze meter under the conditions of a D65 light source and a 10° field of view.

[0217] The haze meter used was "HM-150" manufactured by Murakami Color Research Laboratory.

[0218] 2. Examples 1 to 11, Comparative Examples 1 to 4

[0219] <Manufacturing of multilayer bodies>

[0220] A multilayer body of protective film / polycarbonate film / protective film was produced to have the layer structure shown in Table 2 or Table 3. Specifically, the production was carried out as follows.

[0221] In the process of manufacturing the polycarbonate film, the first roller and the second roller were used for compression bonding and cooling and solidification. After the polycarbonate film was produced, in the process on the downstream side, the protective films shown in Tables 2 and 3 were laminated using a metal mirror roller and a rubber roller at a linear pressure of 3 N / mm, and wound on the core material for 300 M at a tension of 100 N / m to produce a multilayer body of protective film / polycarbonate film / protective film. At this time, the protective film a and the protective film b, the one with a larger Wa value, was wound on the outside.

[0222] The obtained multilayer body was evaluated as follows.

[0223] <Tensile elastic modulus of multilayer laminate [MPa]>

[0224] The multilayer body was punched into a test piece shape (JIS K 7127 test piece model 1B), and a tensile test was performed in the sheet extrusion direction (flow direction) using Autograph (AGS-500NX manufactured by Shimadzu Corporation). Based on JIS K7127, the stress difference at the test speed of 1 mm / min and the deformation of 0.0005 and 0.0025 was divided by the deformation difference to obtain the tensile modulus.

[0225] <Arithmetic mean waviness Ma [μm] of the adhesive layer after peeling>

[0226] The surface shape of the adhesive surface of the protective film peeled from the multilayer body was measured using a scanning white light interference microscope VS1800 manufactured by Hitachi High-Technologies Co., Ltd. The measurement conditions and processing conditions were as follows, and the arithmetic mean waviness Ma of the mid-wavelength component when the band was decomposed was used.

[0227] Measurement conditions

[0228] CCD camera for measurement: high pixel

[0229] Tube: 0.5x

[0230] Objective lens: 2.5x

[0231] Measurement mode: wave mode

[0232] Wavelength filter: 530nm White

[0233] Observation area: 10721.79×10728.91μm 2 ,

[0234] Image size: 1000×1000 pixels

[0235] Processing conditions

[0236] Face correction: 4 times

[0237] Band decomposition: short wavelength λs500μm, medium wavelength λl3000μm, long wavelength (maximum: 5361.7664μm)

[0238] The adhesive layer Ma after peeling off the larger value of the protective film a and the protective film b is taken as the maximum value of Ma [unit: μm].

[0239] <Cellulite>

[0240] After the laminate was stored at 23°C and 50% relative humidity for 24 hours, the protective film was peeled off from the laminate, and light was irradiated from the polycarbonate film surface at 45° so that the illuminance on the film surface became 1000 Lux. The orange peel texture (concavity and convexity) was evaluated by visual observation of the outline of the light source reflected on the film surface. The evaluation was performed by 5 experts and judged by majority vote.

[0241] A: Strong cellulite lines were produced;

[0242] B: Weak cellulite was produced;

[0243] C: No cellulite.

[0244] <Sinking defects in polycarbonate films>

[0245] The number of pit defects of polycarbonate was evaluated as follows.

[0246] The protective film was peeled off from the multilayer body, and light was irradiated from the side surface of the polycarbonate film at an angle of 20° to 70° to a 10 cm × 10 cm area so that the illumination on the film surface was 1000 Lux. The reflected light was used for visual observation to detect point defects. The surface shape of the defect was measured using a scanning white light interference microscope VS1800 manufactured by Hitachi High-Technologies Corporation, and the number of defects with a diameter of 100 μm or more was counted. The average value of the result after repeating this three times was calculated to calculate the number of defects per 1 m 2 The number of .

[0247] A: The number of point defects is 100 / m 2 the following.

[0248] B: The number of point defects is greater than 100 / m 2 And 1000 pieces / m 2 the following.

[0249] C: The number of point defects is greater than 1000 / m 2 And 2000 pieces / m 2 the following.

[0250] D: The number of point defects is greater than 2000 / m 2 .

[0251] <Roll bulge>

[0252] The multilayer body 300M was rolled up, and the roll bulge was visually checked. At this time, the resin layer Wa of the protective film a and the resin layer Wa of the protective film b, the resin layer with the larger value, was rolled outward. The evaluation was performed by 5 experts, and the judgment was made by majority vote.

[0253] A: Strong curling occurred.

[0254] B: Weak curling occurred.

[0255] C: No curling occurred.

[0256] <Warp>

[0257] The warpage of the multilayer body was evaluated as follows.

[0258] The multilayer body was cut into a piece of 150 mm x 150 mm and placed on a flat plate, and the maximum value of the height of the film end from the ground contact surface was measured.

[0259] A: The warpage is 5 mm or less.

[0260] B: The warpage is greater than 5 mm and less than 15 mm.

[0261] C: Warping is greater than 15 mm.

[0262] <Stress during heated tensile test>

[0263] The multilayer body was punched into a test piece shape (JIS K 7127 test piece model 1B), the protective film a was peeled off, and an Autograph (AGS-500NX manufactured by Shimadzu Corporation) and a thermostatic bath THC1WF-200T for AGS-500NX were used. After the thermostatic bath was heated to 150±5°C, the test piece was installed, and after holding for 1 minute, a tensile test was performed at 100 mm / min until the deformation was 100%, and the maximum stress at this time was measured. This was repeated 3 times, and the average value was adopted.

[0264] A: The stress during the heating test is 5 MPa or less.

[0265] B: The stress during the heating test was greater than 5 MPa and less than 10 MPa.

[0266] C: The stress during the heating test is greater than 10 MPa.

[0267] <Haze>

[0268] The haze (unit: %) of the multilayer body was measured using a haze meter under the conditions of a D65 light source and a 10° field of view.

[0269] The haze meter used was "HM-150" manufactured by Murakami Color Research Laboratory.

[0270] [Table 2]

[0271]

[0272] [Table 3]

[0273]

[0274] *2 The larger value of Wa of the protective film a and Wa of the protective film b is expressed as the arithmetic mean waviness Wa of the resin layer [unit: μm].

[0275] From the above results, it is clear that in the multilayer body of the present invention, when the protective film is peeled off, orange peel is less likely to occur on the surface of the polycarbonate film (Examples 1 to 11).

[0276] In addition, when polyolefin films were used as the resin layers on both surfaces (Examples 1, 2, 5, and 6), the warping of the multilayer body was suppressed, and the stress during the heating tensile test was effectively suppressed.

[0277] In addition, when a polyester film is used as the resin layer on at least one surface (Examples 3, 4, 7, 8, and 10), the occurrence of curling bulges can be effectively suppressed. In particular, in Examples 4 and 8, by peeling off the protective film composed of the resin layer containing polyester, the stress during the heating tensile test can be reduced.

[0278] In addition, when polyester films were used on both surfaces as the resin layer (Examples 3 and 7), the depression defect of the multilayer body was effectively suppressed.

[0279] In addition, a thin protective film can reduce waviness (Example 11).

[0280] On the other hand, when Ma of the adhesive layer after peeling was larger than 0.12 μm (Comparative Examples 1 and 2), orange peel was generated.

[0281] On the other hand, when the thickness of the polycarbonate film was thick (Comparative Examples 3 and 4), no orange peel was generated regardless of the value of the arithmetic mean waviness Ma.

[0282] Explanation of symbols

[0283] 1: multilayer body; 2: polycarbonate film; 3: protective film; 4: adhesive layer; 5: layer containing resin (resin layer); 20: concavity and convexity of the film; 21: roughness curve; 22: waviness curve.

Claims

1. A multilayer body, characterized in that: have: A polycarbonate film having a thickness of 20 to 75 μm; and a protective film provided on at least one surface of the polycarbonate film, The protective film comprises an adhesive layer capable of being peeled from the polycarbonate film and a layer containing a resin, The adhesive layer is in contact with the polycarbonate film, and When the polycarbonate film is peeled off from the multilayer body, the arithmetic mean waviness Ma of the waviness of the adhesive layer is 0.01 to 0.12 μm, wherein the waviness does not include waviness having a waviness width of less than 500 μm and greater than 3000 μm.

2. The multilayer body according to claim 1, characterized in that: The polycarbonate film has a thickness of less than 67 μm.

3. The multilayer body according to claim 1 or 2, characterized in that: The resin-containing layer contains a polyolefin resin and / or a polyester resin.

4. The multilayer body according to claim 1 or 2, characterized in that: The multilayer body comprises the protective films on both sides of the polycarbonate film, respectively. The resin-containing layers each contain a polyolefin resin.

5. The multilayer body according to claim 1 or 2, characterized in that: The multilayer body comprises the protective films on both sides of the polycarbonate film, respectively. The resin-containing layer on one surface of the polycarbonate film contains a polyolefin resin, and the resin-containing layer on the other surface of the polycarbonate film contains a polyester resin.

6. The multilayer body according to claim 1 or 2, characterized in that: The multilayer body comprises the protective films on both sides of the polycarbonate film, respectively. The resin-containing layers each contain a polyester resin.

7. The multilayer body according to any one of claims 1 to 6, characterized in that: The number of point defects on the surface of the resin-containing layer is 2000 / m 2 the following.

8. The multilayer body according to any one of claims 1 to 7, characterized in that: Satisfy any of the following conditions 1 and 2, Condition 1: The tensile elastic modulus of the multilayer body is 1800 MPa or more; Condition 2: The tensile elastic modulus of the multilayer body is less than 1800 MPa, and the arithmetic mean waviness Wa of the outermost layer of the resin-containing layer is 0.15 μm or more, excluding waviness having a waviness width of less than 500 μm and greater than 3000 μm.

9. The multilayer body according to any one of claims 1 to 8, characterized in that: The arithmetic mean waviness Wa of the waviness of the layer on the outermost side of the layer containing the resin is 0.03 to 0.35 μm, and the waviness does not include waviness having a waviness width of less than 500 μm and more than 3000 μm.

10. The multilayer body according to any one of claims 1 to 8, characterized in that: The arithmetic mean waviness Wa of the waviness of the layer on the outermost side of the layer containing the resin is 0.03 to 0.30 μm, and the waviness does not include waviness having a waviness width of less than 500 μm and more than 3000 μm.

11. The multilayer body according to any one of claims 1 to 10, characterized in that: The haze is 30% or less.

12. The multilayer body according to any one of claims 1 to 10, characterized in that: The haze is 10% or less.

13. The multilayer body according to any one of claims 1 to 12, characterized in that: The glass transition temperature of the polycarbonate film measured by differential scanning calorimetry (DSC) is 115 to 142°C.

14. The multilayer body according to any one of claims 1 to 13, characterized in that: The polycarbonate film contains a polycarbonate having a terminal structure represented by formula (1), In formula (1), R 1 represents an alkyl group having 8 to 36 carbon atoms or an alkenyl group having 8 to 30 carbon atoms, R 2 Each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 6 to 12 carbon atoms, n represents an integer of 0 to 4, and * represents a bonding site to another site.

15. A wound body, characterized in that: A multilayer body according to any one of claims 1 to 13 comprising a core material and wound around the core material.

16. The wound body according to claim 15, characterized in that: The resin-containing layer having an arithmetic average waviness Wa of 0.03 to 0.35 μm is wound on a side farther from the core material, and the waviness does not include waviness having a width of less than 500 μm and greater than 3000 μm.

17. The wound body according to claim 15 or 16, characterized in that: The resin-containing layer having an arithmetic average waviness Wa of 0.03 to 0.30 μm is wound on a side farther from the core material, and the waviness does not include waviness having a width of less than 500 μm and greater than 3000 μm.

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