Process film, laminate having resin composition layer, laminate roll, and method for producing resin composition film

Abstract

To provide a process film that is excellent in surface smoothness, transparency, quality, and handling performance.SOLUTION: A process film includes at least one surface that is an A surface having a skewness Ssk of -5 or more and 0 or less and an arithmetic average roughness Sa of 3 nm or more and 100 nm or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a process film that can be used as a support when producing a resin composition film and can impart slipperiness while maintaining the surface of the produced resin composition film smooth, a laminate of resin composition films, a resin composition film, and a method for producing a resin composition film. [Background technology]

[0002] Films are used in a variety of applications, including packaging, surface protection, supports in the manufacturing processes of other components, sanitary products, agricultural products, construction products, medical products, and capacitors. Among these, films used for surface protection and support are called process films because they are used in the manufacturing processes of optical components and electronic materials. In recent years, with the increasing demand for more advanced properties and higher quality for optical components and electronic materials, the required properties and quality for such process films have also increased.

[0003] In particular, when a resin composition film for optical applications is formed using a processing film, the surface shape of the processing film must be highly controlled. For example, Patent Document 1 describes an example in which an uneven structure due to a phase separation structure is formed and transferred onto the surface of a processing film, thereby improving the antiglare properties of the resin composition film for optical applications and suppressing glare.

[0004] Furthermore, a casting film is required to have a smooth surface in order to prevent the transfer of dents, but if the surface smoothness is too high, the slipperiness of the resin composition film formed on the casting film will be reduced, and the quality may be reduced due to the generation of foreign matter due to scraping of the surface, wrinkles, etc. For example, Patent Document 2 describes an example in which the slipperiness of an optical film is improved and defects are reduced by adding fine particles to the surface of a polyethylene terephthalate (PET) film and controlling the surface roughness to a specific level.

[0005] Furthermore, Patent Document 3 describes an example in which the depth of the valleys on the film surface and the volume of voids on the valley side are kept low and high-temperature voltage resistance properties are improved by controlling specific equipment and conditions in the casting process after melt-extrusion of the polymer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-173546 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-307038 [Patent Document 3] International Publication No. 2017 / 077752 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the method described in Patent Document 1 above sometimes resulted in a large uneven structure on the surface of the transferred resin composition film, resulting in poor optical properties and quality. The method described in Patent Document 2 also had the problem of low protrusion height on the surface of the transferred resin composition film, resulting in insufficient slipperiness. The method described in Patent Document 3 also had the problem of high protrusion height on the surface and large recess depth on the surface of the transferred resin composition film, resulting in poor optical properties and quality. The object of the present invention is to solve the above-mentioned problems. Specifically, the object of the present invention is to provide a process film that, when used as a process film in the production process of a resin composition film, can achieve both improved optical properties and quality of the resulting resin composition film and ease of handling. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the casting film of the present invention has the following configuration: When the surface having a skewness Ssk of -5 to 0 and an arithmetic mean roughness Sa of 3 to 100 nm is defined as surface A, at least one surface is surface A.

[0009] The laminate of the present invention has the following configuration: that is, a laminate having a resin composition layer on the side A of the film.

[0010] The method for producing a resin composition film of the present invention has the following configuration. That is, it is a method for producing a resin composition film comprising at least the following steps 1 to 3 in this order: Step 1: applying a coating agent containing a resin composition to side A of the film; Step 2: solidifying the coating agent containing the resin composition to form a resin composition layer and produce a laminate; Step 3: peeling the resin composition layer from the laminate to obtain a resin composition film. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a process film that, when used as a process film in the process of producing a resin composition film, can achieve both improved optical properties and quality of the resulting resin composition film and easy handling. The process film of the present invention can be suitably used as a support when producing a resin composition film used for optical components or electronic materials, and the resin composition film produced using this has both surface smoothness and easy slippage. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 10 is a diagram conceptually showing areal material ratio Smr2 and protruding portion height Spk. DETAILED DESCRIPTION OF THE INVENTION

[0013] The process film of the present invention has at least one side as side A, where side A is defined as a side having a skewness Ssk of -5 or more and an arithmetic mean roughness Sa of 3 nm or more and 100 nm or less. Having side A on at least one side of the process film can improve the smoothness and handleability of the resin composition film obtained by applying a coating agent containing a resin composition to side A, solidifying it, and peeling it off. Hereinafter, the skewness Ssk and arithmetic mean roughness Sa may be simply referred to as Ssk and Sa, respectively. The process film of the present invention includes a protective film that protects the film during transport, a support film used as a support when producing a resin composition film, and a cover film that covers the side of the resin composition film that is not in contact with the support film when forming the resin composition film on the support film.

[0014] Ssk is a parameter defined in ISO25178-2:2012 and is also called skewness. Details of the measurement conditions are shown in the Examples. Generally, when Ssk>0, there are many fine peaks, and when Ssk<0, there are many fine valleys. The majority of industrial films have a protruding structure on their surface to ensure easy slippage, and it is extremely rare to find a film with a recessed structure between these protruding structures. It is important that the film of the present invention has many recessed structures (valleys) relative to the protruding structures (peaks), which corresponds to an Ssk of 0 or less.

[0015] When Ssk is greater than 0, the film surface has more protrusions than depressions. Therefore, for example, when used as a support film, fewer protrusions are transferred to the resin composition film obtained by applying a coating containing a resin composition to the film, solidifying it, and peeling it off. As a result, the resulting resin composition film may lack lubricity and have poor handleability. On the other hand, when Ssk is less than -5, the film surface has extremely few protrusions. Therefore, the film may have poor lubricity during film formation or when processed into a support film, resulting in poor handleability.

[0016] To achieve an Ssk of -5 or more and 0 or less, for example, the raw material composition of the film may be within the range described below, and the film-forming conditions may be within the range described below. In particular, Ssk can be reduced by including at least one of an olefin-based elastomer resin and a polypropylene block copolymer in the film in addition to the resin that is the main component, performing initial longitudinal stretching at a temperature equal to or higher than the softening temperature of the rubber domains derived from the olefin-based elastomer resin and the polypropylene block copolymer formed in the resin that is the main component, and then performing two-stage longitudinal stretching at a temperature equal to or higher than the softening temperature of the resin that is the main component of the film.

[0017] In the casting film of the present invention, from the viewpoint of transferring and forming protrusions on the resin composition film obtained by applying a coating agent containing a resin composition to Side A, solidifying it, and peeling it off, Ssk of Side A is preferably −0.001 or less, more preferably −0.01 or less. Furthermore, from the viewpoint of increasing the protrusion height of the resin composition film obtained by the above method and improving handleability, Ssk is preferably −3 or more, more preferably −1.5 or more, and even more preferably −0.5 or more.

[0018] In the casting film of the present invention, a coating agent containing a resin composition is applied to side A, solidified, and peeled off to form protrusions of an appropriate height on the resulting resin composition film, and from the viewpoint of improving handleability, the Sa of side A is preferably 7 nm or more, more preferably 10 nm or more. Furthermore, from the viewpoint of the smoothness of the resin composition film obtained by the above method, the Sa of side A is preferably 65 nm or less, more preferably 40 nm or less, even more preferably 24 nm or less, and particularly preferably 20 nm or less. If the Sa of side A is less than 3 nm, the smoothness of the casting film or the resin composition film produced using the casting film may be deteriorated. On the other hand, if the Sa of side A is greater than 100 nm, when the resin composition film produced using the casting film is wound up, the protrusions on the surface of the resin composition film that was in contact with the casting film may be transferred to the other surface of the resin composition film, resulting in dents, which may degrade the quality of the resin composition film.

[0019] There are no particular limitations on the method for adjusting the Sa of Side A to 3 nm or more and 100 nm or less, or to the above-mentioned preferred range. For example, a method can be used in which a component that is incompatible with the component most abundant in the casting film and has a lower melting point or glass transition temperature than the component most abundant in the casting film is added. Increasing the amount of such a component can increase the Sa value of Side A. Furthermore, the Sa value of Side A can be reduced by uniaxially or biaxially stretching the casting film or by increasing the stretching ratio.

[0020] The casting film of the present invention preferably has a surface area ratio Smr2 of 70% or more and 98% or less, from the viewpoint of improving the smoothness and handleability of the resin composition film obtained by applying a coating agent containing a resin composition to the A side, solidifying it, and peeling it off. Hereinafter, the surface area ratio Smr2 may be simply referred to as Smr2. From the viewpoint of the handleability of the resin composition film, the upper limit of Smr2 of the A side is preferably 95%, more preferably 92%, and even more preferably 90%. On the other hand, from the viewpoint of the smoothness of the resin composition film, the lower limit of Smr2 is preferably 80%, more preferably 85%.

[0021] Smr2 is a parameter specified in ISO 25178-2:2012, and detailed measurement conditions are described in the Examples. As shown in Figure 1, which conceptually illustrates the areal material ratio Smr2 and the protruding portion peak height Spk, Smr2 (reference numeral 1) refers to the areal material ratio at the point where the load curve intersects the boundary between the protruding valleys and the core portion, when the secant line of the load curve, drawn at the center of the roughness curve (reference numeral 2) with the difference in areal material ratios Smr, ΔSmr, at 40%, is the line with the gentlest slope, which is defined as an equivalent line (reference numeral 3). The core portion is defined as the area between the two height positions where the equivalent line intersects the vertical axis at areal material ratios of 0% and 100%, and represents the proportion of protruding valleys. The load curve is a load curve for a surface and is expressed as a function of the areal material ratio at the cutting level.

[0022] Typically, a larger Smr2 value indicates smaller core valleys and finer depressions on the film surface, while a smaller Smr2 value indicates larger core valleys and coarser depressions on the film surface. When Smr2 is greater than 98%, the depth of the depressions on the film surface is insufficient. Therefore, for example, when used as a support film, the height of the protrusions transferred to the resin composition film obtained by applying a coating agent containing a resin composition to the film, solidifying it, and peeling it off becomes low. As a result, the resulting resin composition film may lack lubricity and have poor handleability. On the other hand, when Smr2 is less than 70%, the core valleys are extremely large, there are few flat cores, and the base (film surface) of the film has a wavy shape. Therefore, for example, when used as a support film as described above, the transparency of the resulting resin composition film may be impaired.

[0023] To achieve Smr2 of 70% or more and 98% or less, for example, the amount of olefin-based elastomer resin in the film can be increased, an olefin-based elastomer with a lower softening temperature can be used, the initial longitudinal stretching ratio during longitudinal stretching can be increased, or the initial longitudinal stretching temperature can be lowered.

[0024] The casting film of the present invention may be prepared by applying a coating agent containing a resin composition onto the casting film and drying it in a high-temperature oven at approximately 130°C. From the viewpoint of reducing wrinkles in the oven, the Young's modulus in the longitudinal direction of the film at 130°C is preferably 100 MPa or more and 500 MPa or less. From the above viewpoint, the lower limit of the Young's modulus in the longitudinal direction of the film at 130°C is preferably 120 MPa. A higher Young's modulus in the longitudinal direction of the film at 130°C is preferable, but from the viewpoint of feasibility, the upper limit is 500 MPa. In the present invention, the longitudinal direction refers to the direction in which the film is unwound from the film roll. When the longitudinal direction is unknown, the longitudinal direction of a polypropylene film is defined as the direction perpendicular to the main orientation. In the present invention, the direction perpendicular to the main orientation refers to the direction showing the highest Young's modulus when an arbitrary direction is defined as 0° in the plane of the film and the Young's modulus is measured in each direction forming an angle of 0° to 175° in 5° increments relative to the arbitrary direction. The Young's modulus can be measured by heating the film at 130° C. for 1 minute and then conducting a tensile test on the film at a tensile speed of 300 mm / min. The detailed measurement conditions will be described later.

[0025] Because the Young's modulus in the longitudinal direction of the film at 130°C is 100 MPa or more, when the film is used as a processing film, the film is prevented from stretching when a coating agent containing a dendritic composition is applied and solidified in a high-temperature process, and the occurrence of wrinkles associated with this is also reduced.

[0026] To achieve a Young's modulus of 100 MPa or more and 500 MPa or less in the longitudinal direction of the film at 130°C, or in the above-mentioned preferred range, the raw material composition of the film can be set within the range described below, and the film-forming conditions can be set within the range described below. In particular, it is effective to use a raw material with a high degree of crystallinity, to increase the preheating temperature during longitudinal and transverse stretching, and to perform uniform high-magnification stretching at a low temperature.

[0027] The surface free energy of the casting film of the present invention is preferably 15 mN / m or more and 35 mN / m or less from the viewpoint of facilitating the peeling of the resin composition film formed on the surface of Layer A when used as a casting film and enhancing affinity with the coating material used to form the resin composition film. From the above viewpoints, the upper limit of the surface free energy of Side A is preferably 32 mN / m, and more preferably 29 mN / m. The lower the surface free energy, the better the releasability, which is preferable, but from the viewpoint of feasibility, 15 mN / m is the lower limit. By setting the surface free energy to 35 mN / m or less, the resin composition film can be easily peeled from the casting film. The surface free energy can be measured using a known contact angle meter using four types of liquids as the measuring liquid: water, ethylene glycol, formamide, and methylene iodide. Detailed measurement conditions are shown in the examples.

[0028] The method for setting the surface free energy to 15 mN / m or more and 35 mN / m or less is not particularly limited, but for example, a method can be used in which the raw material composition of the process film is within the range described below and the film-forming conditions are within the range described below. In particular, it is effective to use polypropylene resin as the main component of the surface layer of the film corresponding to side A (the film itself in the case of a single-layer structure; the same applies hereinafter) or to provide a coating layer with release properties on side A, but from the standpoints of component transfer to the dendritic composition film and cost, it is more preferable to use polypropylene resin as the main component of the surface layer of the film corresponding to side A.

[0029] Although the components constituting the casting film of the present invention are not particularly limited, it is preferable that the main component is a thermoplastic resin. Examples of thermoplastic resins include the above-mentioned polypropylene resin, as well as polyolefin resins such as polystyrene (PS) resin, styrene-based elastomer resin, polymethylpentene (PMP) resin, cyclic olefin (COP) resin, and cyclic olefin copolymer (COC) resin; polyester resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, and polyethylene terephthalate (PEN) resin; polysulfone (PSU) resin, polyethersulfone (PES) resin; and polyolefin resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene terephthalate (PEN). Polysulfone resins such as phenylsulfone (PPSU) resin, polyarylene sulfide resins such as polyphenylene sulfide (PPS) resin, polyphenylene sulfide ketone resin, polyphenylene sulfide sulfone resin, and polyphenylene sulfide ketone sulfone resin, polyaryletherketone resins such as polyetherketone (PEK) resin, polyetheretherketone (PEEK) resin, polyetherketoneketone (PEKK) resin, polyetheretherketoneketone (PEEKK) resin, and polyetherketoneetherketoneketone (PEKEKK) resin, polytetrafluoroethylene (PTFE) resin (also called tetrafluoroethylene resin), polytetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA) resin (also called tetrafluoroethylene-perfluoroalkylvinylether copolymer resin), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin (also called tetrafluoroethylene-hexafluoropropylene copolymer resin), and tetrafluoroethylene-ethylene copolymer (ETFE) resin Fluorine resins such as ethylene tetrafluoride resin (also called ethylene trifluoride copolymer resin), polychlorotrifluoroethylene (PCTFE) resin (also called ethylene trifluoride resin), polyvinylidene fluoride (PVDE) resin (also called vinylidene fluoride resin), vinylidene fluoride-tetrafluoroethylene-hexafluoropyrene copolymer resin, polyacetal resin, liquid crystal polymer (LCP) resin, polycarbonate (PC) resin, polyarylate (PAR) resin, acrylic resin, polymethyl methacrylate resin (PMMA),Examples of suitable materials include polyurethane resins (PU), polyurethane acrylate resins, cellulose, cellulose derivatives (e.g., acetyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, etc.), petroleum resins, terpene resins, terpene phenolic resins, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, low-crystalline or amorphous ethylene-α-olefin copolymers, ethylene-propylene-diene terpolymers, crystalline polypropylene, polypropylene, propylene-ethylene copolymers (random and / or block copolymers), propylene-α-olefin copolymers, propylene-ethylene-α-olefin copolymers, polybutene, 4-methyl-1-pentene-α-olefin copolymers, ethylene-ethyl (meth)acrylate copolymers, ethylene-methyl (meth)acrylate copolymers, ethylene-n-butyl (meth)acrylate copolymers, and ethylene-vinyl acetate copolymers. These raw materials can also be used in modified form, derivatives, or copolymers with other compounds. They can be used alone or in combination. From the viewpoint of adjusting Ssk to 0 or less, it is preferable to use a polyolefin resin or polyester resin that can be easily biaxially stretched, and it is preferable to contain at least one pair of mutually incompatible components so as to form a microphase-separated structure with an average domain diameter of 5 μm or less before stretching.

[0030] When polypropylene resin is used as the main component of the casting film of the present invention, the inclusion of a low-crystalline polyolefin resin can reduce the crystallinity of the cast film after melt extrusion, thereby suppressing the formation of coarse protrusions in the film after stretching. Low-crystalline polyolefin resins preferably have a lower stereoregularity in the polymer molecular structure and / or a lower crystallinity than polypropylene resins. Methods for reducing crystallinity include copolymerization with a comonomer. While low-crystalline polyolefin resins also include resins without a melting point, for resins with a melting point, the melting point of the low-crystalline polyolefin resin is preferably lower than that of polypropylene resin, more preferably 50°C to 135°C, even more preferably 60°C to 130°C, particularly preferably 60°C to 120°C, and most preferably 60°C to 100°C. It is also preferable to use a laminate film in which at least one surface layer contains a low-crystalline polyolefin resin with a melting point of 50°C to 135°C or within the above-mentioned preferred range.

[0031] The melting point of the low-crystalline polyolefin resin is preferably 50°C or higher to prevent the film surface from melting or sticking to the rolls when conveyed through the preheating / stretching rolls. Furthermore, the melting point of the low-crystalline polyolefin resin is preferably 135°C or lower to partially melt and roughen the film surface during stretching. When the film has a laminated structure and at least one surface layer contains a low-crystalline polyolefin resin, the content of the low-crystalline polyolefin resin in the surface layer containing the low-crystalline polyolefin resin is preferably 80% by mass or lower, more preferably 70% by mass or lower, even more preferably 40% by mass or lower, and most preferably 25% by mass or lower, when the total components of the layer are taken as 100% by mass. Furthermore, the lower limit of the content of the low-crystalline polyolefin resin is more preferably 5% by mass or higher, even more preferably 15% by mass or higher, and most preferably 20% by mass or higher.

[0032] The low-crystalline polyolefin resin is preferably a low-crystalline polypropylene resin that is compatible with polypropylene resin, such as a copolymer of propylene and an α-olefin or a polypropylene resin with low stereoregularity. For example, commercially available products such as "Wintec" (registered trademark) manufactured by Japan Polypropylene Corporation, which is a polypropylene random copolymer, or "Elmodu" (registered trademark) manufactured by Idemitsu Kosan Co., Ltd., which is a low-stereoregular polypropylene resin, can be appropriately selected and used.

[0033] When polypropylene resin is used as the main component of the casting film of the present invention, it is preferable to contain a rubber domain-forming resin. Here, the rubber domain-forming resin refers to a resin that can form rubber domains in the film by blending with polypropylene resin. Examples include resins that contain rubber domains, such as polypropylene block copolymers, and thermoplastic elastomers that are not completely compatible with polypropylene resin and form rubber domains in the polypropylene resin matrix. By using such an embodiment, the rubber domains are stretched more than the matrix resin during longitudinal stretching, thereby forming a recessed structure on the film surface.

[0034] The rubber domain-forming resin is not particularly limited as long as it can form rubber domains in the film, but is preferably at least one of a thermoplastic elastomer and a polypropylene block copolymer. Polyolefin-based thermoplastic elastomers are particularly preferred due to their high affinity with polypropylene resins. A thermoplastic elastomer is an elastomer that softens and becomes fluid when heated and returns to a rubbery state when cooled. The upper limit of the Vicat softening temperature of the rubber domain-forming resin is preferably 130°C, more preferably 122°C, and even more preferably 110°C. Meanwhile, the lower limit of the Vicat softening temperature is preferably 50°C, more preferably 65°C, even more preferably 80°C, and particularly preferably 90°C.

[0035] When a rubber domain-forming resin is contained, the upper limit of the content of the rubber domain-forming resin in the layer is more preferably 35% by mass, even more preferably 25% by mass, even more preferably 17% by mass, and particularly preferably 12% by mass, when the total components of the layer containing the rubber domain-forming resin are taken as 100% by mass. The lower limit of the content of the rubber domain-forming resin is more preferably 1% by mass, even more preferably 4% by mass, even more preferably 6% by mass, and particularly preferably 8% by mass. Adjusting the content of the rubber domain-forming resin in this way makes it easy to achieve both the slip properties of the casting film itself and the quality of the resin composition film formed on its surface.

[0036] The casting film of the present invention may also contain various additives, such as weathering agents, clarifying agents, crystal nucleating agents, antioxidants, heat stabilizers, slipping agents, antistatic agents, antiblocking agents, fillers, viscosity modifiers, color inhibitors, leveling agents, surfactants, and mold release agents, as long as the additives do not impair the object of the present invention.

[0037] Next, the laminate and laminate roll of the present invention will be described. The laminate of the present invention is characterized by having a resin composition layer on side A of the casting film of the present invention. The laminate roll of the present invention is characterized by being obtained by winding up the laminate. By using such an embodiment, it is possible to peel the resin composition layer from the laminate and obtain a resin composition film with excellent smoothness and slipperiness. Here, the resin composition layer refers to a layer in which the resin is more than 50% by mass and not more than 100% by mass of all components constituting the film.

[0038] Next, a method for producing a resin composition film using the casting film of the present invention will be described. The method for producing a resin composition film using the casting film of the present invention comprises at least the following steps 1 to 3, in this order: Step 1: Applying a coating agent containing a resin composition to side A of the casting film of the present invention. Step 2: Solidifying the coating agent containing the resin composition to form a resin composition layer and produce a laminate. Step 3: Peeling the resin composition layer from the laminate to obtain a resin composition film. Here, "comprising steps 1 to 3 in this order" means that steps 1 to 3 are performed in this order before obtaining the resin composition film, regardless of whether other steps are performed before step 1, between steps 1 and 2, between steps 2 and 3, or after step 3. By adopting this embodiment, the surface shape of the casting film of the present invention is transferred to the resin composition film, resulting in a resin composition film with excellent smoothness and slipperiness.

[0039] The resin composition contained in the coating material applied in step 1 is not particularly limited, but from the viewpoint of coatability, it is preferable to use a monomer that is a raw material for a thermosetting resin or a photocurable resin, a monomer that is a raw material for a curable resin that hardens by the reaction of two or more components, a thermoplastic resin, or a monomer that is a raw material for a thermoplastic resin. In accordance with the components contained in the resin composition film formed in step 3, it is preferable to select as the resin composition a monomer in which the components are dispersed in a solvent or which generates the components when hardened.

[0040] Preferred embodiments of the resin component constituting the resin composition contained in the coating agent include, for example, the following two embodiments. The first embodiment is an embodiment containing a thermosetting resin. Thermosetting resins are not particularly limited, but examples thereof include phenolic resins, melamine resins, and epoxy resins. These resins can also be used in modified forms, derivatives, and copolymers with other compounds. They can also be used alone or in combination of two or more types.

[0041] The second embodiment is an embodiment including a thermoplastic resin. The thermoplastic resin used in the resin composition film is not particularly limited, but examples thereof include polyamide resin, polyolefin resin, polyester resin, polyarylene sulfide resin, acrylic resin, polyurethane resin, polyvinylpyrrolidone resin, polyethylene oxide resin, polyaryl ether ketone resin, etc. From the viewpoint of coatability, it is preferable to use a polyolefin resin or polyester resin that can be easily dispersed in a solvent, or an acrylic resin, polyurethane resin, or polyethylene oxide resin that can be polymerized as a monomer by light or heat after coating to obtain a cured film.

[0042] Polyolefin resins include polystyrene (PS), styrene-based elastomer, polymethylpentene (PMP), cyclic olefin (COP), cyclic olefin copolymer (COC), polyethylene, and polypropylene. Polyolefin resins can be used as coating materials by dispersing them in nonpolar solvents such as toluene, xylene, mesitylene, cyclohexane, and decahydronaphthalene.

[0043] The polyester resin may be not only a saturated linear polyester but also a compound having a trivalent or higher ester-forming component or a compound having a reactive unsaturated group as the polyester component. The polyester resin preferably contains sulfonic acid, carboxylic acid, or a salt thereof to improve its solubility and dispersibility in water. Furthermore, the polyester resin may be modified by grafting a compound having a carbon double bond with a polysiloxane group, a fluorinated alkyl group, an epoxy group, an amide group, or the like. When using a polyester resin, it can be dispersed or dissolved in an aqueous solvent such as water or alcohol and used as a coating material.

[0044] The acrylic resin may be an acrylic resin obtained by copolymerizing a vinyl monomer having a reactive functional group with alkyl acrylate and / or alkyl methacrylate as the main component. Examples of the reactive functional group include a carboxyl group or its salts, an acid anhydride group, a sulfonic acid group or its salts, an amide group, an amino group, a hydroxyl group, and an epoxy group. In particular, from the viewpoints of adhesion to the casting film and coating strength, aqueous polyacrylic resins containing a carboxyl group, an amino group, a hydroxyl group, an epoxy group, or the like are preferred. Furthermore, the acrylic resin may be modified by graft or block polymerization of a compound having a polysiloxane group, a fluorinated alkyl group, an epoxy group, or the like.

[0045] Polyurethane resins can be aqueous urethane resins whose main raw materials are polyisocyanates, polyols, chain extenders, crosslinkers, etc. A common method for converting urethane resins to aqueous solutions is to use polyisocyanates, polyols, and chain extenders with hydrophilic groups. Alternatively, a method can be used in which unreacted isocyanate groups in polyurethane are reacted with a compound having a hydrophilic group. Polyurethane resins can also be modified by graft or block polymerization of compounds having polysiloxane groups, fluorinated alkyl groups, epoxy groups, etc. Modified resins, derivatives, and copolymers with other compounds can also be used. These resins can be used alone or in combination.

[0046] The method for applying the coating agent containing the resin composition to side A of the casting film of the present invention in step 1 is not particularly limited, and can be appropriately selected depending on the viscosity of the coating agent and the method for solidifying the resin composition, from methods such as coating with a bar coater, blade coater, gravure coater, die coater, spin coater, inkjet coater, and reverse coater, and methods of vapor-depositing the coating agent onto the casting film, etc. These methods may be used alone, or two or more methods may be used in succession in combination.

[0047] In step 2, the method for solidifying the coating material containing the resin composition is not particularly limited, and methods such as solvent removal by drying, ultraviolet curing, and thermal curing can be appropriately selected depending on the characteristics of the coating material containing the resin composition. These methods may be used alone or in combination of two or more methods. To promote solidification, initiators and catalysts for radical polymerization, anionic polymerization, and cationic polymerization may be added to the coating material containing the resin composition depending on the characteristics of the resin composition. Initiators that initiate reactions using heat or light can be selected appropriately depending on the solidification characteristics of the resin composition. Similarly, catalysts such as acids, bases, oxidizing agents, and reducing agents can be selected depending on the solidification characteristics of the resin composition.

[0048] In step 3, the method for peeling the resin composition layer from the laminate to obtain a resin composition film is not particularly limited and can be appropriately selected depending on the adhesion and Young's modulus of the resin composition film and the processing film. For example, a method in which the resin composition film and the processing film are wound up on separate cores and then peeled, or a method in which the laminate is cut into sheets and then peeled by hand can be selected.

[0049] In the method for producing a resin composition film using the casting film of the present invention, the method for performing steps 1 to 3 is not particularly limited, and may be a so-called batch method using a sheet of casting film, or a so-called roll-to-roll method using a wound-up casting film. A combination of these methods is also possible. Among these, the roll-to-roll method is preferred from the viewpoint of productivity of the resin composition film. By using the casting film of the present invention in step 1, the casting film of the present invention and the resin composition layer formed using the casting film of the present invention as a support each have high slip properties. Therefore, it is easy to adopt the roll-to-roll method, which has excellent productivity.

[0050] Next, the resin composition film and resin composition film roll of the present invention will be described. The resin composition film of the present invention is characterized in that the protrusion peak height Spk on both sides is 100 nm or less, and the surface with a skewness Ssk of 0 or more is the C-surface, and the larger of the protrusion peak heights Spk on both sides is Spk_h, and the smaller of the two is Spk_l, and at least one side is the C-surface, and Spk_h / Spk_l is 1.5 or more. Furthermore, the resin composition film roll of the present invention is obtained by winding the resin composition film of the present invention. Note that, hereinafter, the protrusion peak height Spk may be simply referred to as Spk, and the larger and smaller of the protrusion peak heights Spk on both sides may also be referred to as Spk_h and Spk_l.

[0051] Spk is a parameter specified in ISO 25178-2:2012, and detailed measurement conditions are described in the Examples. As shown in Figure 1, which is a conceptual diagram of the areal material ratio Smr2 and the protrusion peak height Spk, Spk (symbol 4) is the average height of the protrusion peaks above the core portion, when the secant line of the load curve for the roughness curve (symbol 2) is drawn at the center of the load curve when the difference in areal material ratios Smr, ΔSmr, is set to 40%, and the line with the gentlest slope is taken as the equivalent line (symbol 3), and the core portion is defined as the space between the two height positions where the equivalent line intersects the vertical axis at areal material ratios of 0% and 100%.

[0052] By setting the Spk on both sides to 100 nm or less, the occurrence of dents when the resin composition film is wound into a roll is reduced, and a high-quality resin composition film with excellent appearance can be obtained. The upper limit of the Spk of the resin composition film is preferably 75 nm, more preferably 40 nm, from the viewpoint of improving the quality of the resin composition film. The lower limit of the Spk of the resin composition film is preferably 0.1 nm, more preferably 5 nm, from the viewpoint of maintaining high lubricity.

[0053] Furthermore, by setting Spk_h / Spk_l to 1.5 or more, the fine protrusions on the surface with the higher Spk value particularly enhance the slipperiness, making it less likely for wrinkles to form when the resin composition film is wound into a roll. From the above perspective, the lower limit of Spk_h / Spk_l is preferably 1.8. The upper limit of Spk_h / Spk_l is not particularly limited, but is preferably 100.

[0054] Furthermore, by making the Ssk of at least one surface 0 or more, in other words, by making at least one surface a C surface, the slipperiness of the resin composition film can be improved even if the Spk is low. The lower limit of the skewness Ssk of the C surface is preferably 0.01. The upper limit of the skewness Ssk of the C surface is not particularly limited, but is preferably 5.0 or less.

[0055] A method for obtaining a resin composition film in which Spk on both sides is 100 nm or less or in the above-mentioned preferred range, at least one side is a C-face, and Spk_h / Spk_l is 1.5 or more or in the above-mentioned preferred range includes a method for producing a resin composition film using the process film of the present invention as a support by the above-mentioned production method.

[0056] The resin composition film of the present invention can also contain various additives, such as weathering agents, clarifying agents, crystal nucleating agents, antioxidants, heat stabilizers, slipping agents, antistatic agents, antiblocking agents, fillers, viscosity modifiers, coloring inhibitors, surfactants, mold release agents, etc., within the scope of not impairing the object of the present invention. In order to incorporate these components into the resin composition film of the present invention, a method can be used in which these components are added in advance at the coating agent stage.

[0057] Next, a method for producing a casting film of the present invention will be described using an embodiment in which a polyolefin resin is used as the main component, but the casting film of the present invention is not necessarily limited to this.

[0058] First, 100 parts by mass of polypropylene resin, 0 to 50 parts by mass of branched polypropylene resin, 0 to 80 parts by mass of low-crystalline polyolefin resin, and 0 to 30 parts by mass of rubber domain-forming resin are fed from a metering hopper to a twin-screw extruder, melt-kneaded at 260°C, and extruded into strands from a die. The extruded resin composition is cooled and solidified in a 25°C water bath and cut into chips to obtain a resin composition for the surface layer (I). The resin composition for the surface layer (I) is fed to a single-screw extruder, and then 100 parts by mass of polypropylene resin and 0 to 50 parts by mass of branched polypropylene resin are dry-blended and fed to a single-screw extruder for the base layer (II layer). Each component is melt-extruded at 200 to 280°C, preferably 220 to 280°C, and even more preferably 240 to 270°C. Note that a lower limit of 0 parts by mass means that the component is not an essential component.

[0059] Then, after removing foreign matter and modified polymers using a filter installed midway through the polymer pipe, the mixture is laminated in a multi-manifold composite T-die to form a two-type, three-layer structure of I layer / II layer / I layer, and discharged onto a casting drum to obtain a laminated unstretched sheet having a layer structure of I layer / II layer / I layer. In this case, the lamination thickness ratio is preferably in the range of 1 / 8 / 1 to 1 / 60 / 1.

[0060] The surface temperature of the casting drum is preferably 10 to 45°C, more preferably 15 to 35°C, and even more preferably 15 to 25°C. The method for adhering the film to the casting drum may be any of electrostatic application, adhesion methods utilizing the surface tension of water, air knife methods, press roll methods, and underwater casting methods. However, the air knife method is preferred because it provides good flatness and allows control of surface roughness. The air temperature of the air knife is preferably 10 to 30°C, and the blown air speed is preferably 130 to 150 m / s. It is also preferable to appropriately adjust the position of the air knife so that air flows downstream of the film formation process to prevent vibration of the sheet.

[0061] The resulting unstretched sheet is introduced into a longitudinal stretching process. The longitudinal stretching process refers to a process in which the sheet is stretched in its running direction (longitudinal direction). In the longitudinal stretching process, after initial longitudinal stretching, the sheet is stretched at a higher temperature and at a higher stretching ratio than in the initial longitudinal stretching. This two-stage stretching process can efficiently form a depression structure. First, in the initial stretching, the sheet is preheated at a temperature higher than the softening temperature of the rubber domain-forming resin and stretched at a low stretching ratio, thereby stretching the rubber domains more than the matrix. This stretching can form a depression structure on the film surface. In the initial longitudinal stretching, the unstretched sheet is preheated by contacting it with multiple metal rolls maintained at a temperature of 80°C to 130°C, preferably 90°C to 120°C, and more preferably 90°C to 110°C, and is then stretched in the longitudinal direction by 1.1 to 3.0 times, preferably 1.3 to 2.5 times, between rolls with different peripheral speeds.

[0062] Thereafter, it is preferable to obtain a longitudinally uniaxially stretched film by longitudinally stretching at a high ratio at a temperature higher than the initial longitudinal stretching temperature in order to stabilize the subsequent transverse stretching. More specifically, it is preferable to preheat the film by contacting it with a metal roll maintained at 110°C or higher and 150°C or lower, preferably 115°C or higher and 140°C or lower, and even more preferably 120°C or higher and 140°C or lower, and stretch it between rolls with different peripheral speeds. The total longitudinal stretching ratio in the two-stage stretching is preferably 3.0 to 6.0 times, more preferably 4.0 to 6.0 times, even more preferably 4.5 to 5.5 times, and particularly preferably 4.5 to 5.0 times. If the total stretching ratio is less than 3.0 times, the orientation of the film may be weak, resulting in a decrease in strength.

[0063] The longitudinally uniaxially stretched film is then introduced into a tenter, where both widthwise ends are held with clips and preheated, followed by transverse stretching in the width direction at a ratio of 7.0 to 13. Here, transverse stretching refers to stretching the longitudinally uniaxially stretched film in the width direction. It is important to retain the depressions formed on the film surface when transversely stretching the longitudinally uniaxially stretched film. For this reason, the preheating and stretching temperatures are 120°C to 175°C, preferably 120°C to 165°C, and more preferably 140°C to 160°C.

[0064] In the subsequent heat treatment and relaxation process, the film is heat-set at a temperature of 140°C to 180°C, preferably 140°C to 170°C, more preferably 150°C to 170°C, and even more preferably 160°C to 170°C, while being tension-held across the width with clips. The film is then cooled at 80°C to 100°C while being tension-held across the width with clips, and then guided outside the tenter. The clips on both ends of the film are then released, and the film edges are slit in the winding process, resulting in a film product roll. Heat setting can relieve residual stress within the film and reduce the thermal shrinkage rate.

[0065] The casting film obtained as described above can be preferably used as a support when producing films for optical components or electronic materials, where the presence of protrusions on the product can impair its functionality.

[0066] Next, an example of a method for producing a resin composition film using the casting film of the present invention will be described taking a method for producing a polyurethane acrylate film as an example, but the present invention is not necessarily limited to this.

[0067] The processed film obtained by the above-mentioned method is wound into a roll and placed in a bar coater. A coating agent consisting of a resin composition containing 50 parts by weight of commercially available urethane acrylate (e.g., viscosity at 25°C of 600,000 mPa·s, weight-average molecular weight Mw of 1600, and glass transition temperature of 10°C), 30 to 100 parts by weight of commercially available methyl ethyl ketone, and 0.1 to 5 parts by weight of commercially available 1-hydroxycyclohexyl phenyl ketone is applied to side A of the film to a film thickness of 1 μm to 100 μm. The film is then placed in a hot air dryer and heated to 50°C to 150°C to remove the solvent. The film is then placed in a hot air dryer and heated to 70°C to 100°C to remove the solvent. Subsequently, the film is dried under a nitrogen atmosphere using a UV lamp with an irradiation output of 200 W / cm. 2 ~600W / cm 2 , cumulative light intensity 80mJ / cm 2~140mJ / cm 2 The coating material on the casting film is cured by irradiating it with ultraviolet light at a temperature of 1000°C to obtain a laminate consisting of a resin composition layer made of polyurethane acrylate and a casting film layer. The resin composition layer is peeled off from the casting film of this laminate to obtain a resin composition film made of polyurethane acrylate.

[0068] Another example of a resin composition film is a resin composition film made of cellulose acetate propionate. A coating agent containing 100 parts by weight of commercially available cellulose acetate propionate (acetyl group substitution degree + propionyl group substitution degree = 2.5, weight average molecular weight = 180,000, Mw / Mn = 3.0), 8 parts by weight of triphenyl phosphate, 2 parts by weight of ethyl phthalyl ethyl glycolate, 360 parts by weight of methylene chloride, 60 parts by weight of ethanol, 0.5 parts by weight of Tinuvin 109 (manufactured by Ciba Japan Co., Ltd.), and 0.5 parts by weight of Tinuvin 171 (manufactured by Ciba Japan Co., Ltd.) was applied to side A of the casting film to a film thickness of 1 μm to 100 μm. The film is then placed in a hot air dryer and heated to 10°C to 50°C to remove the solvent and cure the coating on the casting film, yielding a laminate consisting of a resin composition layer made of cellulose acetate propionate and the casting film. The laminate is then wound up to obtain a laminate roll with the resin composition layer on side A of the casting film. The laminate is then unwound from the laminate roll and the resin composition layer is peeled off from the casting film, yielding a resin composition film made of cellulose acetate propionate.

[0069] Another example is a resin composition film made of polyetherimide. A coating mixture of 15 parts by weight of a commercially available polyetherimide resin (manufactured by SABIC, trade name "ULTEM" (registered trademark) 1010, Vicat softening point temperature 215°C) and 85 parts by weight of N-methyl-2-pyrrolidone is applied to side A of the casting film to a film thickness of 1 μm to 100 μm. This is then introduced into a hot air dryer and heated to 50°C to 150°C to remove the solvent and cure the coating on the casting film, resulting in a laminate consisting of a polyetherimide resin composition layer and the casting film. The laminate is then wound up to obtain a laminate roll with the resin composition layer on side A of the casting film. The laminate is then unwound from the laminate roll, and the resin composition layer is peeled off from the casting film to obtain a polyetherimide resin composition film. [Example]

[0070] The present invention will be described in detail below with reference to examples. The properties were measured and evaluated by the following methods.

[0071] (1) Film thickness Measurements were made using a micro thickness meter (manufactured by Anritsu Corporation). The process film was sampled in a 10 cm square area, and the thickness was measured at five arbitrarily selected points. The average of the obtained values ​​was taken as the film thickness of the process film.

[0072] (2) Arithmetic mean roughness Sa, average surface load area ratio Smr2, skewness Ssk, protruding peak height Spk Each parameter was measured and calculated in accordance with ISO25178 (2012). However, measurements were performed using a scanning white light interference microscope "VS1540" (manufactured by Hitachi High-Tech Science Corporation; measurement conditions and device configuration are described below), and the captured image was interpolated (fully interpolated) using the attached analysis software, surface correction was performed using a polynomial fourth-order approximation, and then processed with a median filter (3 x 3 pixels) to obtain the measured electro-magnetic surface. The S-filter nesting index of the S-filter was set to 0.455. Measurements were performed on both sides of a 5 cm x 5 cm square cut of process film. The intersection of the diagonal lines was designated as the first measurement point (point 1). Points 2, 3, 4, and 5 were located 1 cm away from the starting point, clockwise, toward each of the four corners. The midpoint of the line connecting points 2 and 3 was designated point 6, the midpoint of the line connecting points 3 and 4 was designated point 7, the midpoint of the line connecting points 4 and 5 was designated point 8, and the midpoint of the line connecting points 5 and 2 was designated point 9. A total of nine measurement points were determined, and measurements were performed at each of these points. From the measurement results, Sa, Smr2, Ssk, and Spk were calculated for each measurement position according to the procedure described above. The average values ​​of the five values ​​obtained for each parameter, excluding the first, second, eighth, and ninth largest values, were used as the Sa, Smr2, Ssk, and Spk of the process film.

[0073] <Measurement conditions and equipment configuration> Objective lens: 10x Telescope tube: 1x Zoom lens: 1x Wavelength filter: 530nm white Measurement mode: Wave Measurement software: VS-Measure 10.0.4.0 Analysis software: VS-Viewer 10.0.3.0 Measurement area: 561.1μm×561.5μm Number of pixels: 1,024 x 1,024.

[0074] (3) Young's modulus in the longitudinal direction of the processed film at 130°C A rectangular sample measuring 150 mm (longitudinal direction) x 10 mm (transverse direction) was cut out. Using a tensile tester (Orientec Co., Ltd., "Tensilon" (registered trademark) AMF / RTA-100), the longitudinal direction of the sample was set as the tensile direction. Young's modulus was measured five times at 130°C and 65% RH in accordance with the method specified in JIS K 7161 (1994). The average of the obtained values ​​was taken as the Young's modulus of the processed film in the longitudinal direction at 130°C. The initial chuck distance was 50 mm, the tensile speed was 300 mm / min, and the point at which the load passed 1 N after the start of the test was taken as the origin of elongation. The film thickness used to calculate Young's modulus was the value measured in (1) above.

[0075] (4) Surface free energy Four types of liquids were used as measurement solutions: water, ethylene glycol, formamide, and methylene iodide. The static contact angle of each liquid with the cast film surface was determined using a contact angle meter, Model CA-D, manufactured by Kyowa Interface Science Co., Ltd. The static contact angle was measured 30 seconds after each liquid was dropped onto the cast film surface. The contact angle obtained for each liquid and each component of the surface tension of the measured liquid were substituted into the following equation, and the simultaneous equation consisting of four equations was solved for γSd, γSp, and γSh. (γSd γLd) 1 / 2 +(γSp γLp) 1 / 2 +(γSh γLh) 1 / 2 =γL(1+cosθ) / 2 However, γS = γSd + γSp + γSh γL=γLd+γLp+γLh γS, γSd, γSp, and γSh represent the surface free energy, dispersion force component, polar force component, and hydrogen bond component of the process film surface, respectively, and γL, γLd, γLp, and γLh represent the surface free energy, dispersion force component, polar force component, and hydrogen bond component of the measurement liquid used, respectively. Here, the surface tension of each liquid used was the value proposed by Panzer (J. Panzer, J. Colloid Interface Sci., 44, 142 (1973)).

[0076] (5) Evaluation of the slipperiness of processing films A coating agent consisting of a resin composition made by mixing 50 parts by mass of commercially available urethane acrylate (viscosity at 25°C: 600,000 mPa·s, weight-average molecular weight Mw: 1600, glass transition temperature: 10°C), 50 parts by mass of commercially available methyl ethyl ketone, and 3 parts by mass of commercially available 1-hydroxycyclohexyl phenyl ketone was applied to side A of a 21 cm x 30 cm processed film using a bar coater to a film thickness of 45 μm. The film was then placed in a hot air dryer and heated to 80°C to remove the solvent. Subsequently, a UV lamp was used under a nitrogen atmosphere to apply the coating agent at an irradiation output of 400 W / cm. 2 , cumulative light intensity 120mJ / cm 2 The coating material on the processing film was irradiated with ultraviolet light at 1000 kJ / cm² to harden the coating material on the processing film, and then the resin composition layer was peeled off to obtain a resin composition film made of polyurethane acrylate. When both sides of the processing film were side A, the coating material was applied to the side with the lower Sa. For processing films that did not have side A, the coating material was applied to the side with the lower Sa, and a resin composition film was obtained using the same procedure. Furthermore, for processing films that did not have side A and had the same Sa on both sides, the coating material was applied to the side with the lower Ssk value, and a resin composition film for evaluation was obtained using the same procedure. This was repeated five times to obtain five resin composition films for evaluation.

[0077] Thereafter, using a slip tester manufactured by Toyo Seiki Kogyo Co., Ltd., the obtained resin compositions were stacked so that the surfaces that had been in contact with the casting film were in contact with each other, and the dynamic friction coefficient μd was measured in accordance with JIS K 7125 (1999) at a load of 200 g, 25°C, and 65% RH when the longitudinal directions of the resin composition films for evaluation were rubbed against each other. The samples were cut into rectangular shapes with a width of 80 mm and a length of 200 mm, and five sets (10 pieces) of samples were cut out. When cutting out the samples, one set was cut out from one resin composition film for evaluation, and a region 2 cm from the edge of the resin composition film for evaluation was not used. Five measurements were performed, and the average value was used as the dynamic friction coefficient μd. Based on the dynamic friction coefficient μd of the resin composition film for evaluation, the slip property-imparting effect of the casting film was evaluated according to the following criteria.

[0078] The resin composition films were evaluated as resin composition films for evaluation, and the lubricity-imparting effect of the process film was evaluated according to the following criteria. That is, in this specification, the resin composition films described in Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-4 were evaluated as resin composition films for evaluation, and the evaluation was carried out as described above. Excellent: μd is 0.45 or less. Good: μd is greater than 0.45 and less than or equal to 0.55. Acceptable: μd is greater than 0.55 and less than 0.60. Unacceptable: μd is greater than 0.60.

[0079] (6) Quality of resin composition film (smoothing effect of process film) Two resin composition films obtained by the method (5) were sampled into squares measuring 100 mm wide and 100 mm long. The surface of the resin composition film that had been in contact with the process film was designated the P surface, and the other surface was designated the Q surface. The P surface and the Q surface were then stacked so that they were in contact with each other. The sample was then sandwiched between two acrylic plates (100 mm wide and 100 mm long), a load of 3 kg was applied, and the sample was left standing for 24 hours in an atmosphere at 23 ° C. After 24 hours, the Q surface that had been in contact with the P surface was visually observed, and the smoothing effect of the process film was evaluated according to the following criteria. Note that, for evaluation of the resin composition film as described in Example 2-1, the resin composition film was used as a resin composition film for evaluation, and the quality of the resin composition film (smoothing effect of the process film) was evaluated according to the following criteria. That is, in this specification, the resin composition films described in Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-4 were evaluated as resin composition films for evaluation, and the evaluation was carried out as described above. Excellent: The surface was clean immediately after the load was released, and was the same as before the load was applied. Good: Immediately after the load is released, slight unevenness is observed, but after 10 minutes the unevenness disappears. Acceptable: Mild unevenness was observed even 10 minutes after the load was released. Unacceptable: Strong unevenness was observed.

[0080] <Components used in each example and comparative example> A1: Homopolypropylene resin (Prime Polymer Co., Ltd., MFR: 3.0 g / 10 min, melting point: 164°C) A2: Homopolypropylene resin (Sumitomo Chemical Co., Ltd., MFR: 7.5 g / 10 min, melting point: 163°C) A3: Homopolypropylene resin (Prime Polymer Co., Ltd., MFR: 3.0 g / 10 min, melting point 161°C) B1: Branched polypropylene resin ("WAYMAX" (registered trademark) MFX6, manufactured by Japan Polypropylene Corporation, MFR: 3.0 g / 10 min) B2: Branched chain polypropylene resin ("WAYMAX" (registered trademark) MFX3, manufactured by Japan Polypropylene Corporation, MFR: 8.0 g / 10 min) B3: Branched polypropylene resin (Borealis "Daploy" (registered trademark) WB140HMS, MFR: 2.1 g / 10 min) C1: Random polypropylene resin ("WINTEC" (registered trademark) WFW4M, manufactured by Japan Polypropylene Corporation, MFR: 7.0 g / 10 min) C2: Polypropylene resin (manufactured by Idemitsu Kosan Co., Ltd., "L-MODU" (registered trademark) S901, melting point 80°C) D1: Thermoplastic elastomer resin (Japan Polypropylene Corporation, "WELNEX" (registered trademark) RFX4V, Vicat softening temperature: 100°C) D2: Block polypropylene resin (Sumitomo Chemical Co., Ltd. "Noblen" (registered trademark) AW564, Vicat softening temperature: 101°C) D3: Thermoplastic elastomer resin (Japan Polypropylene Corporation, "WELNEX" (registered trademark) RFX4VM, Vicat softening temperature: 115°C) D4: Thermoplastic elastomer resin ("Tafmer" (registered trademark) XM7070, manufactured by Mitsui Chemicals, Inc., Vicat softening temperature: 67°C) Polyester A: A polyester resin having an intrinsic viscosity of 0.68 obtained by the following procedure. (Procedure: 100 parts by mass of dimethyl terephthalate and 60 parts by mass of ethylene glycol were used as starting materials, and 0.09 parts by mass of magnesium acetate tetrahydrate was added to a reactor as a catalyst. The reaction was initiated at 150°C, and the reaction temperature was gradually increased as methanol was distilled off, reaching 230°C after 3 hours. After 4 hours, the transesterification reaction was essentially complete. 0.04 parts by mass of ethyl acid phosphate was added to this reaction mixture, and then 0.04 parts by mass of antimony trioxide was added, and a polycondensation reaction was carried out for 4 hours. That is, the temperature was gradually increased from 230°C to 280°C. Meanwhile, the pressure was gradually reduced from atmospheric pressure and finally reached 0.3 mmHg. After the start of the reaction, the reaction was stopped at a point corresponding to an intrinsic viscosity of 0.68 due to changes in the stirring power of the reactor, and the polymer was discharged under nitrogen pressure.) Polyester B: A polyester resin having an intrinsic viscosity of 0.67 obtained by the following procedure (procedure: the same method as in the production method of Polyester A was used, except that after adding 0.04 parts by mass of ethyl phosphate, 0.3 parts by mass of synthetic calcium carbonate particles having an average particle size of 0.7 μm and a particle size distribution value of 1.70, which were dispersed in ethylene glycol, and 0.04 parts by mass of antimony trioxide were added, and the polycondensation reaction was stopped at the point corresponding to an intrinsic viscosity of 0.66). Polyester C: A polyester resin having an intrinsic viscosity of 0.67 obtained by the following procedure (procedure: the same method as in the production method of Polyester B was used, except that the particles added were amorphous silica particles having an average particle size of 1.4 μm and a particle size distribution value of 2.5, and the amount added was 0.1 part). UA1: urethane acrylate (manufactured by Negami Chemical Industrial Co., Ltd., viscosity at 25°C: 600,000 mPa·s, weight-average molecular weight Mw: 1600, glass transition temperature: 10°C) CAP1: commercially available cellulose acetate propionate (acetyl group substitution degree + propionyl group substitution degree: 2.5, weight average molecular weight: 180,000, Mw / Mn: 3.0) UVA1: Tinuvin 109 (manufactured by Ciba Japan Co., Ltd.) UVA2: Tinuvin 171 (manufactured by Ciba Japan Co., Ltd.) PEI1: Polyetherimide resin (manufactured by SABIC, trade name "ULTEM" (registered trademark) 1010, Vicat softening point temperature: 215°C) (Example 1-1) 50 parts by mass of A1, 20 parts by mass of B1, 20 parts by mass of C1, which is a low-crystalline polypropylene resin, and 10 parts by mass of D1, which is a rubber domain-forming resin, were mixed in this ratio from a metering hopper to a twin-screw extruder, and melt-kneaded at 250 ° C., extruded from a die in the form of a strand, cooled and solidified in a water bath at 25 ° C., and cut into chips to obtain a resin composition for the surface layer (I). As a raw material for the surface layer (I), 100 parts by mass of the resin composition was fed to a single-screw extruder, and as a raw material for the inner layer (II), 95 parts by mass of the above A1 and 5 parts by mass of B1 were dry-blended and fed to another single-screw melt extruder, each melt-extruded at 250 ° C., and foreign matter was removed with a sintered filter with a 20 μm cut. The molten resin composition was then laminated in a feedblock-type composite T-die so that the thickness ratio of surface layer (I) / inner layer (II) / surface layer (I) was 1 / 24 / 1, and molded into a sheet. The sheet was then extruded onto a casting drum with a surface temperature controlled at 20 ° C. and adhered to the casting drum using an air knife. The sheet on the casting drum was then cooled by spraying compressed air onto the non-cooled drum surface to obtain an unstretched sheet. The unstretched sheet was then preheated to 90 ° C. with a ceramic roll and initially stretched 1.3 times in the longitudinal direction of the film between 90 ° C. rolls with a peripheral speed difference. The sheet was then preheated to 140 ° C., and a second-stage longitudinal stretching was performed at a ratio of 3.5 times. The uniaxially stretched film was then inserted into a tenter-type stretching machine with both widthwise ends held in place by clips. After preheating at 160°C for 3 seconds, it was stretched 9.8 times in the widthwise direction at 150°C and then heat-treated at 165°C with 10% relaxation in the widthwise direction. After a cooling step at 100°C, the film was guided outside the tenter-type stretching machine. The clips on both widthwise ends of the film were released, and the film was wound around a core to obtain a 12 μm-thick cast film. The physical properties and evaluation results of the resulting cast film are shown in Table 1.

[0081] [Table 1]

[0082] (Examples 1-2, 1-3, 1-4, 1-6, 1-7, Comparative Examples 1-1, 1-2, 1-4, 1-6) A film having the thickness shown in Table 1 was obtained in the same manner as in Example 1, except that the composition, layer structure, lamination ratio, and film-forming conditions of each layer were as shown in Table 1. The physical properties and evaluation results of the obtained film are also shown in Table 1. The film thickness was adjusted by adjusting the discharge rate during extrusion.

[0083] (Examples 1-5) A dry blend of 65 parts by weight of A1, 20 parts by weight of C1, and 15 parts by weight of D1 was fed into a single-screw melt extruder, melt extruded at 260 ° C, and foreign matter was removed using a sintered filter with a 20 μm cutoff. The mixture was then discharged onto a casting drum with a surface temperature controlled at 20 ° C and adhered to the casting drum using an air knife. The sheet on the casting drum was then cooled by spraying compressed air onto the non-cooled drum surface to obtain a single-layer unstretched sheet. The unstretched sheet was then preheated to 125 ° C with a ceramic roll and initially stretched 1.2 times in the longitudinal direction of the film between 125 ° C rolls with a peripheral speed difference. The sheet was then preheated to 138 ° C, and a second-stage longitudinal stretching was performed at a ratio of 3.4 times. The film was then introduced into a tenter-type stretching machine with the edges held by clips. After preheating at 168°C for 3 seconds, it was stretched 7.5 times at 163°C and then heat-treated at 173°C with 16% relaxation in the width direction. After a cooling step at 100°C, the film was introduced outside the tenter-type stretching machine, the clips at both edges in the width direction were released, and the film was wound around a core to obtain a 22μm-thick cast film. The physical properties and evaluation results of the resulting cast film are shown in Table 1.

[0084] (Comparative Examples 1-3) Coating Solution X was prepared by dissolving 5.65 parts by weight of an acrylic resin having a polymerizable unsaturated group in the side chain, 1.2 parts by weight of cellulose acetate propionate, 4 parts by weight of a multifunctional acrylic UV-curable compound, 2.77 parts by weight of an acrylic UV-curable compound, and 0.53 parts by weight of a photoinitiator in a mixed solvent of 25 parts by weight of methyl ethyl ketone (MEK) and 12.15 parts by weight of 1-butanol. Coating Solution X was then coated onto one side of a biaxially stretched PET film that had been treated for easy adhesion by the Mayer bar coating method, and dried at 95°C for 2 minutes to form a 7 μm-thick coating layer. The film was then irradiated with ultraviolet light from a high-pressure mercury lamp (manufactured by Eye Graphics) for approximately 10 seconds (integrated light dose of approximately 400 mJ / cm). 2 The resulting cast film was subjected to UV irradiation and UV curing treatment. The physical properties and evaluation results of the resulting cast film are shown in Table 1.

[0085] (Comparative Examples 1-5) A mixed raw material pellet was prepared by dry blending 70 parts by weight of A3 and 30 parts by weight of D1. The mixed raw material pellet was fed from a hopper into a single-screw extruder, melted, and extruded through a single-layer die as a single-layer resin layer. The extruded resin layer was cooled and solidified while being pressed by air pressure using an air knife onto a cooling drum controlled at 35°C, yielding a 900 μm thick unstretched film. The resulting unstretched film was simultaneously biaxially stretched using a Bruckner batch biaxial stretching machine "KAROIV" under the following stretching conditions to obtain a process film with a total thickness of approximately 100 μm. The physical properties and evaluation results of the resulting process film are shown in Table 1.

[0086] Stretching conditions: Preheating temperature set at 165°C, preheating time 2 minutes, stretching temperature (longitudinal stretching temperature and transverse stretching temperature) 165°C, stretching speed 100% / sec. Stretching ratio of unstretched film: After simultaneous biaxial stretching to 3.3 times in the longitudinal direction and 3.3 times in the transverse direction, the film was relaxed in an oven set at 170°C to 3 times in the longitudinal direction and 3 times in the transverse direction, and then heat-set for 20 seconds.

[0087] (Comparative Examples 1-7) Anhydrous magnesium chloride, decane, and 2-ethylhexyl alcohol were mixed, and phthalic anhydride was added to the heated solution, followed by further stirring. The solution was cooled and then added dropwise to titanium tetrachloride cooled to -20°C. The mixture was then heated, diisobutyl phthalate was added, and the mixture was stirred, followed by filtration to obtain a solid. The obtained solid was washed with decane and hexane to obtain a titanium catalyst for use in propylene polymerization.

[0088] Propylene polymerization was carried out using the titanium catalyst, triethylaluminum as a cocatalyst, and hydrogen as a chain transfer agent. The resulting product was deactivated and thoroughly washed with propylene monomer to obtain a polypropylene resin. The MFR of this polypropylene resin was 2.5 g / 10 min and the mesopentad fraction (mmmm) was 0.980.

[0089] To 99.7% by mass of the obtained polypropylene resin, 0.1% by mass of BHT as an antioxidant and 0.2% by mass of Irganox-1010 as an antioxidant were added, and then the mixture was kneaded at a temperature of 260°C and pelletized to obtain a polypropylene resin composition.

[0090] 100% by mass of the polypropylene resin composition was fed to a single-screw melt extruder, melt-extruded at 250°C, and then subjected to removal of foreign matter using a sintered filter with a 25 μm cutoff. The shear rate applied to the T-die during extrusion was 300 sec -1The molten polypropylene resin composition extruded from a T-die was brought into close contact with four consecutive casting drums to produce a molten sheet. The consecutive casting drums had the same diameter and were numbered CD1, CD2, CD3, and CD4 from upstream to downstream. The film path was set so that each side of the cast sheet alternated in contact with each drum. The surface temperatures of CD1 and CD2 were 30°C, and those of CD3 and CD4 were 90°C. The molten sheet remained in close contact with each of the casting drums (CD1, CD2, CD3, and CD4) for 0.4 seconds. An air knife and edge spot air were used to bring the sheet into close contact with the first casting drum, CD1. The air temperature of the air knife was adjusted to 30°C. The ambient temperature during the casting process was also adjusted to 30°C. The cast sheet was then preheated using a heated roll to a film temperature of 145°C, after which it was stretched 5.5 times in the longitudinal direction. The stretching speed in the longitudinal direction was 2,000,000% / min, and the neck-down ratio was 98%. The film was then held at the ends with clips and stretched 10 times in the transverse direction at a stretching speed of 30,000% / min at 155°C. It was then heat-treated at 158°C for 7 seconds, resulting in 12% relaxation in the transverse direction. After cooling to room temperature, one side of the film was stretched at 25 W·min / m 2 The film was subjected to a corona discharge treatment at a treatment strength of 1000 kJ / min, and the edge of the film held by the clip was cut and removed. The corona discharge-treated side, which was in contact with CD1, was designated as side A, and the other side, which was in contact with CD2 and was not corona discharge-treated, was designated as side B. The film with the edges removed was wound on a winder to obtain a biaxially oriented polypropylene film with a thickness of 2.5 μm. The physical properties and evaluation results of the resulting processed film are shown in Table 1.

[0091] Example 2-1 The casting film prepared in Example 1-1 was cut into a size of 21 cm x 30 cm, and a coating agent consisting of a resin composition obtained by mixing 50 parts by mass of the above-mentioned urethane acrylate, 50 parts by mass of commercially available methyl ethyl ketone, and 3 parts by mass of commercially available 1-hydroxycyclohexyl phenyl ketone was applied to the A side of the film using a bar coater to a film thickness of 45 μm. This was then placed in a hot air oven and heated at 80°C for 1 minute to remove the solvent. Thereafter, a UV lamp was used under a nitrogen atmosphere to apply an irradiation output of 400 W / cm. 2 , cumulative light intensity 120mJ / cm 2 The coating on the casting film was cured by irradiating it with ultraviolet light, and then the resin composition layer was peeled off to obtain a resin composition film made of polyurethane acrylate. The physical properties and evaluation results of the obtained resin composition film are shown in Table 2.

[0092] [Table 2]

[0093] (Example 2-2) The process film prepared in Example 1-2 was cut to a size of 21 cm x 30 cm, and a coating mixture of 100 parts by weight of the above-mentioned CAP1, 8 parts by weight of triphenyl phosphate, 2 parts by weight of ethyl phthalyl ethyl glycolate, 360 parts by weight of methylene chloride, 60 parts by weight of ethanol, 0.5 parts by weight of UVA1, and 0.5 parts by weight of UVA2 was applied to the A side of the film using a bar coater to a film thickness of 45 μm. Subsequently, the solvent was dried and removed with dry air at 25 ° C., and the coating on the process film was cured. The resin composition layer was then peeled off to obtain a resin composition film composed of cellulose acetate propionate. The physical properties and evaluation results of the obtained resin composition film are also shown in Table 2.

[0094] (Example 2-3) A resin composition film made of cellulose acetate propionate was obtained in the same manner as in Example 2-2, except that the casting film in Example 1-4 was used. The physical properties and evaluation results of the obtained resin composition film are shown in Table 2.

[0095] (Examples 2-4) A resin composition film made of polyurethane acrylate was obtained in the same manner as in Example 2-1, except that the casting film in Example 1-5 was used. The physical properties and evaluation results of the obtained resin composition film are shown in Table 2.

[0096] (Comparative Example 2-1) A resin composition film made of polyurethane acrylate was obtained in the same manner as in Example 2-1, except that the casting film of Comparative Example 1-1 was used. The physical properties and evaluation results of the obtained resin composition film are also shown in Table 2.

[0097] (Comparative Example 2-2) A resin composition film made of cellulose acetate propionate was obtained in the same manner as in Example 2-2, except that the casting film in Comparative Example 1-2 was used. The physical properties and evaluation results of the obtained resin composition film are also shown in Table 2.

[0098] (Comparative Example 2-3) A resin composition film made of cellulose acetate propionate was obtained in the same manner as in Example 2-2, except that the casting film of Comparative Example 1-3 was used. The physical properties and evaluation results of the obtained resin composition film are also shown in Table 2.

[0099] (Comparative Example 2-4) A resin composition film made of polyurethane acrylate was obtained in the same manner as in Example 2, except that the casting film of Comparative Example 1-4 was used. The physical properties and evaluation results of the obtained resin composition film are shown in Table 2. Since Example 1-5 and Comparative Example 1-5 have a single-layer structure, there is no distinction between the surface layer (I) and the inner layer (II), but the compositions of the films of Example 1-5, Comparative Examples 1-5, and 1-6 are listed in the column for surface layer (I) in Table 1. In Examples 1-1 to 1-5 and Comparative Examples 1-1, 1-2, and 1-4, the preheating temperature in longitudinal stretching is the same as the stretching temperature. [Industrial Applicability]

[0100] The film of the present invention can be preferably used as a processing film (particularly a processing film in the manufacturing process of a resin composition film). [Explanation of symbols]

[0101] 1:Smr2 2: Roughness curve 3: Equivalent line 4:Spk

Claims

1. A casting film characterized in that at least one side is side A, where side A is defined as a side having a skewness Ssk of -5 or more and an arithmetic mean roughness Sa of 3 nm or more and 100 nm or less, and the surface layer corresponding to side A is a layer containing a homopolypropylene resin as a main component and containing 0 parts by mass or more of one or more resins selected from a branched polypropylene resin, a low-crystalline polyolefin resin, and a rubber domain-forming resin (thermoplastic elastomer) per 100 parts by mass of the homopolypropylene resin.

2. 2. The casting film according to claim 1, wherein the surface area ratio Smr2 of the A-side is 70% or more and 98% or less.

3. 3. The casting film according to claim 1, wherein the Young's modulus in the longitudinal direction of the film at 130°C is 100 MPa or more and 500 MPa or less.

4. The casting film according to any one of claims 1 to 3, wherein the surface free energy of the A-side is 15 mN / m or more and 35 mN / m or less.

5. A laminate having a resin composition layer on the side A of the casting film according to any one of claims 1 to 4.

6. A laminate roll obtained by winding up the laminate according to claim 5 .

7. A method for producing a resin composition film using the casting film according to any one of claims 1 to 4, comprising at least the following steps 1 to 3 in this order: Step 1: A step of applying a coating agent containing a resin composition to the surface A of the casting film according to any one of claims 1 to 4. Step 2: A step of solidifying the coating agent containing the resin composition to form a resin composition layer and produce a laminate. Step 3: A step of peeling off the resin composition layer from the laminate to obtain a resin composition film.

8. The method for producing a resin composition film according to claim 7 , wherein the resin composition film contains a thermosetting resin or a photocurable resin.

9. The method for producing a resin composition film according to claim 7 , wherein the resin composition film contains a thermoplastic resin.

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