Laminated film

Abstract

The present invention provides a new laminated film comprising two or more polycarbonate resin layers, which combines heat resistance, high surface hardness, and impact resistance. [Solution] A laminated film having a polycarbonate resin layer (B) containing polycarbonate as the main polymer component, and at least one outermost surface having a polycarbonate resin layer (A) containing polycarbonate as the main polymer component, wherein the polycarbonate resin layer (A) contains a total of 40% by mass or more of structural units (a) represented by the following formula (1) and a total of 10% by mass or more of structural units (b) represented by the following formula (2) based on 100% by mass of the total amount of polycarbonate contained in the polycarbonate resin layer (A), and the polycarbonate resin layer (B) contains polycarbonate B-1 as the main polymer component, and the polycarbonate B-1 is a polycarbonate containing 50% by mass or more of structural units (c) represented by the following formula (3).

Description

[Technical Field]

[0001] This invention relates to a laminated film comprising two or more polycarbonate resin layers. [Background technology]

[0002] Polycarbonate, particularly type A polycarbonate made from bisphenol A, which is commonly used, is a polymer with excellent transparency, heat resistance, and impact resistance. Therefore, films made from such polycarbonate are widely used in fields such as automotive parts, card components, building materials, displays, and electrical and electronic components.

[0003] However, while films made primarily from type A polycarbonate polymer offer excellent transparency, heat resistance, and impact resistance, they suffer from low surface hardness, making them susceptible to scratches. Therefore, there was a need to improve the surface hardness of these films.

[0004] As means for improving the surface hardness of a film whose main component polymer is type A polycarbonate, for example, methods such as laminating a layer containing an acrylic resin with high surface hardness, as disclosed in Patent Document 1, and laminating a polycarbonate resin layer whose main component polymer is type C polycarbonate made from bisphenol C, which has high surface hardness, as disclosed in Patent Documents 2 and 3, are known. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2006-205478 [Patent Document 2] Japanese Patent Publication No. 2020-175587 [Patent Document 3] Japanese Patent Publication No. 2010-188719 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, whether the laminated layer contains acrylic resin or polycarbonate resin layer with C-type polycarbonate as the main polymer, the heat resistance of the laminated sheet becomes poor, raising concerns that the laminated film may warp or deform when used at high temperatures.

[0007] Therefore, the present invention relates to a laminated film having two or more polycarbonate resin layers, and aims to provide a new laminated film that can combine heat resistance, high surface hardness, and impact resistance. [Means for solving the problem]

[0008] The present inventors have found that the above problem can be solved by adjusting the composition of each polycarbonate resin layer in a laminated film comprising two or more polycarbonate resin layers. The present invention was completed based on this finding, and its gist is as follows. However, the present invention is not limited to the following embodiments and also includes the scope of substitutions, modifications, etc., that can be made by those skilled in the art.

[0009] [1] A first aspect of the present invention is a laminated film having a polycarbonate resin layer (B) containing polycarbonate as a main polymer, and having a polycarbonate resin layer (A) containing polycarbonate as a main polymer on at least one of its outermost surfaces, The polycarbonate resin layer (A) contains, in total, 40% by mass or more of structural units (a) represented by the following formula (1) and 10% by mass or more of structural units (b) represented by the following formula (2), based on 100% by mass of the total amount of polycarbonate contained in the polycarbonate resin layer (A). The polycarbonate resin layer (B) is a laminated film containing polycarbonate B-1 as the main component polymer, and said polycarbonate B-1 is a polycarbonate containing 50% by mass or more of the structural unit (c) represented by the following formula (3).

[0010] TIFF2026066580000001.tif40170

[0011] TIFF2026066580000002.tif35170

[0012] In formula (1), X is at least one selected from a single bond, an oxygen atom, a sulfur atom, and a divalent organic group. R x and R y are each independently an alkyl group having 1 to 6 carbon atoms. In formula (2), Y is at least one selected from a single bond, an oxygen atom, a sulfur atom, and a divalent organic group.

[0013] TIFF2026066580000003.tif33170

[0014] [2] The second aspect of the present invention is a laminated film in which, in the first aspect, in formula (1), X is a divalent organic group represented by the following formula (4).

[0015] TIFF2026066580000004.tif46170

[0016] In formula (4), R1 and R2 are each independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 24 carbon atoms. R1 and R2 may be bonded to each other to form a ring. * is a bond to the benzene ring in formula (1).

[0017] [3] The third aspect of the present invention is a laminated film in which, in the second aspect, in formula (4), both R1 and R2 are methyl groups.

[0018] [4] The fourth aspect of the present invention is a laminated film in which, in any one of the first to third aspects, formula (1) is represented by the following formula (5).

[0019] TIFF2026066580000005.tif39170

[0020] [5] In the fifth aspect of the present invention, in any one of the first to fourth aspects, in the formula (2), Y is a divalent organic group represented by the following formula (6), and it is a laminated film.

[0021] TIFF2026066580000006.tif38170

[0022] In the formula (6), R3 and R4 are each independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 24 carbon atoms. R3 and R4 may be bonded to each other to form a ring. * is a bond to the benzene ring in the formula (2).

[0023] [6] In the sixth aspect of the present invention, in any one of the first to fifth aspects, the formula (2) is represented by the following formula (7), and it is a laminated film.

[0024] TIFF2026066580000007.tif48170

[0025] [7] In the seventh aspect of the present invention, in any one of the first to sixth aspects, in the polycarbonate resin layer (A), the content mass ratio of the structural unit (a) to the structural unit (b) is 90:10 to 40:60, and it is a laminated film.

[0026] [8] In the eighth aspect of the present invention, in any one of the first to seventh aspects, the polycarbonate resin layer (A) has a glass transition temperature measured in accordance with JIS K7121:2012 of 120°C or higher and 200°C or lower, and it is a laminated film.

[0027] [9] In the ninth aspect of the present invention, in any one of the first to eighth aspects, the polycarbonate resin layer (B) has a glass transition temperature measured in accordance with JIS K7121:2012 of 100°C or higher and 200°C or lower, and it is a laminated film.

[0028]

[10] A tenth aspect of the present invention is a laminated film in which, in any one of the first to nine aspects, the lamination thickness ratio of the polycarbonate resin layer (A) to the polycarbonate resin layer (B) is 1:99 to 99:1.

[0029]

[11] An eleventh aspect of the present invention is a laminated film having a thickness of 0.01 mm or more and 10 mm or less, in any one of the first to ten aspects. [Effects of the Invention]

[0030] The laminated film proposed in this invention can combine heat resistance, high surface hardness, and impact resistance. [Modes for carrying out the invention]

[0031] An example of an embodiment of the present invention will be described below. However, the present invention is not limited to the embodiment described below.

[0032] <Laminated film of the present invention> A laminated film according to an example of an embodiment of the present invention (referred to as "the laminated film of the present invention") is a laminated film having a polycarbonate resin layer (B) whose main component polymer is polycarbonate, and having a polycarbonate resin layer (A) whose main component polymer is polycarbonate on at least one of its outermost surfaces.

[0033] Here, the "main component polymer" refers to the polymer with the highest mass percentage among the polymers contained in the polycarbonate layer (A) or (B). For example, it can be assumed that the polymer contains 50% by mass or more, of which 60% by mass or more, of which 70% by mass or more, of which 80% by mass or more, of which 90% by mass or more, or of which 90% by mass or more (including 100% by mass) is the total amount of polymers contained in the polycarbonate layer (A) or (B) (100% by mass). In this invention, "polymer" refers to a so-called polymer, encompassing synthetic polymers and natural polymers, and is a compound formed by the polymerization of multiple monomers, with a molecular weight of 10,000 or more.

[0034] The laminated film of the present invention has a polycarbonate resin layer (B), and as long as at least one of its outermost surfaces has a polycarbonate resin layer (A), the presence of other layers is optional. For example, typically, a laminated configuration of polycarbonate resin layer (A) / polycarbonate resin layer (B), or polycarbonate resin layer (A) / polycarbonate resin layer (B) / polycarbonate resin layer (A) can be exemplified. In these laminated configurations, there may be "other layers" on the outside of one of the polycarbonate resin layers (A), or there may be "other layers" between the polycarbonate resin layer (A) / polycarbonate resin layer (B) layers, and these "other layers" may be single layers or multilayer layers of two or more layers.

[0035] <Polycarbonate resin layer (A)> The polycarbonate resin layer (A) is a layer containing structural units (a) represented by the following formula (1) and structural units (b) represented by the following formula (2).

[0036] By having a polycarbonate resin layer (A) containing structural units (a) represented by the following formula (1) and structural units (b) represented by the following formula (2) in predetermined proportions on at least one outermost surface of the laminated film of the present invention, the surface hardness can be increased, and the heat resistance can also be increased.

[0037] (Structural unit (a) represented by formula (1)) The structural unit (a) represented by the following formula (1) will be explained.

[0038] TIFF2026066580000008.tif40170

[0039] In formula (1) above, X is at least one selected from a single bond, an oxygen atom, a sulfur atom, and a divalent organic group. In particular, from the viewpoint of improving mechanical strength, such as impact resistance, it is preferable that X is a divalent organic group represented by the following formula (4).

[0040] TIFF2026066580000009.tif46170

[0041] In formula (4), R1 and R2 are each independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 24 carbon atoms. R1 and R2 may be bonded to each other to form a ring. In particular, from the viewpoint of improving mechanical strength, such as impact resistance, it is preferable that both R1 and R2 are methyl groups. * represents the bond to the benzene ring in formula (1).

[0042] In equation (1) above, R x and R y Each of these is an alkyl group having 1 to 6 carbon atoms, and it is preferable that all of them are methyl groups.

[0043] In particular, from the viewpoint of improving hardness, the above formula (1) is more preferably the one represented by formula (5) below, i.e., bisphenol C.

[0044] TIFF2026066580000010.tif39170

[0045] (Structural unit (b) represented by formula (2)) The structural unit (b) represented by the following formula (2) will be explained.

[0046] TIFF2026066580000011.tif35170

[0047] In formula (2), Y is at least one selected from a single bond, an oxygen atom, a sulfur atom, and a divalent organic group. In particular, from the viewpoint of improving mechanical strength, such as impact resistance, it is preferable that Y is a divalent organic group represented by the following formula (6).

[0048] TIFF2026066580000012.tif38170

[0049] In formula (6), R3 and R4 are each independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 24 carbon atoms. R3 and R4 may be bonded to each other to form a ring. * represents a bond to the benzene ring in formula (2).

[0050] In particular, from the viewpoint of improving heat resistance, it is more preferable that the above formula (2) is represented by the following formula (7), i.e., bisphenol TMC.

[0051] TIFF2026066580000013.tif48170

[0052] (Ratio of structural units (a) and (b)) From the viewpoint of improving surface hardness and heat resistance, the polycarbonate resin layer (A) preferably contains a total of 40% by mass or more of structural units (a) represented by the following formula (1) and a total of 10% by mass or more of structural units (b) represented by the following formula (2), based on 100% by mass of the total amount of polycarbonate contained in the polycarbonate resin layer (A). In particular, it is more preferable to contain a total of 42% by mass or more of the structural unit (a) represented by the following formula (1), more preferably 44% by mass or more, more preferably 45% by mass or more, and even more preferably 50% by mass or more. Furthermore, it is even more preferable to contain it in a proportion of 88% by mass or less. On the other hand, it is more preferable to contain a total of 12% by mass or more of the structural unit (b) represented by the following formula (2), more preferably 14% by mass or more, and even more preferably 15% by mass or more. Furthermore, it is even more preferable to contain it in a proportion of 50% by mass or less.

[0053] In the polycarbonate resin layer (A), from the viewpoint of balancing surface hardness and heat resistance, the mass ratio of structural unit (a) to structural unit (b) is preferably 90:10 to 40:60, and more preferably 88:12 to 42:58, of which 86:14 to 44:56, of which 85:15 to 50:50, and of which 85:15 to 45:55.

[0054] (Type of polycarbonate contained in the polycarbonate resin layer (A)) The structural units (a) and (b) may be included as copolymer components of the polycarbonate contained in the polycarbonate resin layer (A), or as mixed components.

[0055] In the case where the polycarbonate resin layer (A) contains structural unit (a) and structural unit (b) as copolymer components, the polycarbonate resin layer (A) may contain at least one type of polycarbonate, and the at least one type of polycarbonate may be a copolymer containing the aforementioned structural unit (a) and structural unit (b) as copolymer components. For example, the polycarbonate resin layer (A) may contain one type of polycarbonate, and this polycarbonate may contain structural unit (a) and structural unit (b) as copolymer components. Alternatively, the polycarbonate resin layer (A) may contain two or more types of polycarbonate, one of which is a polycarbonate containing structural unit (a) and structural unit (b) as copolymer components, and at least one of the other polycarbonates may be a polycarbonate containing structural unit (a), a polycarbonate containing structural unit (b), or a polycarbonate containing both structural units (a) and (b).

[0056] Examples of cases in which the polycarbonate resin layer (A) contains structural unit (a) and structural unit (b) as mixed components include cases in which the polycarbonate resin layer (A) contains at least two types of polycarbonate, one of which is a polycarbonate containing structural unit (a), at least one other type of polycarbonate containing structural unit (b), or a polycarbonate containing both structural units (a) and (b), or cases in which one of which is a polycarbonate containing structural unit (b), at least one other type of polycarbonate containing both structural units (a) and (b).

[0057] Furthermore, mixing polycarbonate containing structural unit (a) and (b) with polycarbonate containing structural unit (b), or mixing polycarbonate containing structural unit (a) and (b) with polycarbonate containing structural unit (a), results in higher compatibility and improved heat resistance compared to mixing polycarbonate containing structural unit (a) with polycarbonate containing structural unit (b). From this viewpoint, the latter is more preferable.

[0058] Specific examples include cases where the polycarbonate contained in the polycarbonate resin layer (A) consists solely of polycarbonate A-1 obtained by copolymerizing bisphenol C and bisphenol TMC, cases where it includes polycarbonate A-1 and polycarbonate A-2 containing bisphenol C, and cases where it includes polycarbonate A-1 and polycarbonate A-4 containing bisphenol TMC. However, it is not limited to these examples.

[0059] The viscosity-average molecular weight (Mv) of polycarbonate A-1 obtained by copolymerizing bisphenol C and bisphenol TMC is preferably 35,000 or less, more preferably 32,000 or less, and more preferably 30,000 or less, from the viewpoint of moldability. On the other hand, if the viscosity-average molecular weight (Mv) is too small, the mechanical strength, such as impact resistance, decreases, so it is preferably 12,000 or more, more preferably 14,000 or more, and more preferably 15,000 or more. The glass transition temperature of the aforementioned polycarbonate A-1, measured in accordance with JIS K7121:2012, is preferably 130°C or higher, more preferably 140°C or higher, and even more preferably 150°C or higher, from the viewpoint of improving heat resistance. On the other hand, if the glass transition temperature is too high, molding becomes difficult, so it is even more preferably 220°C or lower, more preferably 200°C or lower, and even more preferably 180°C or lower. From the viewpoint of moldability, it is preferable that the aforementioned polycarbonate A-1 does not have a crystal melting temperature measured in accordance with JIS K7121:2012. The polycarbonate A-1 has an apparent viscosity at 280°C at a shear rate of 100 (1 / s) of 100 Pa·s or more, from the viewpoint of improving mechanical strength, such as impact resistance, and is more preferably 150 Pa·s or more, and more preferably 200 Pa·s or more. On the other hand, from the viewpoint of moldability, it is preferably 5000 Pa·s or less, and is more preferably 4000 Pa·s or less, and more preferably 3000 Pa·s or less.

[0060] The viscosity-average molecular weight (Mv) of the polycarbonate A-2 containing bisphenol C is preferably 35,000 or less, more preferably 32,000 or less, and more preferably 30,000 or less, from the viewpoint of moldability. On the other hand, if the viscosity-average molecular weight (Mv) is too small, the mechanical strength, such as impact resistance, will decrease, so it is preferably 10,000 or more, more preferably 12,000 or more, and more preferably 15,000 or more. The glass transition temperature of the aforementioned polycarbonate A-2, measured in accordance with JIS K7121:2012, is preferably 80°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher, from the viewpoint of heat resistance. On the other hand, if the glass transition temperature is too high, molding becomes difficult, so it is even more preferably 200°C or lower, more preferably 180°C or lower, and even more preferably 150°C or lower. From the viewpoint of moldability, it is preferable that the aforementioned polycarbonate A-2 does not have a crystal melting temperature measured in accordance with JIS K7121:2012. The polycarbonate A-2 preferably has an apparent viscosity of 100 Pa·s or more at 280°C with a shear rate of 100 (1 / s), from the viewpoint of improving mechanical strength, such as impact resistance, and more preferably 200 Pa·s or more, and more preferably 300 Pa·s or more. On the other hand, from the viewpoint of moldability, it is preferably 5000 Pa·s or less, more preferably 4000 Pa·s or less, and more preferably 3000 Pa·s or less.

[0061] (Other ingredients) The polycarbonate resin layer (A) may optionally contain components other than polycarbonate that include structural units (a) represented by the following formula (1) or structural units (b) represented by the following formula (2), or both of these structural units (a) and (b). Examples include other polycarbonates, other polymers, and additives.

[0062] Other examples of polycarbonates include, for instance, polycarbonate B-1 containing the structural unit (c) represented by formula (3) below, and type A polycarbonate made from bisphenol A, for example. However, the examples are not limited to these.

[0063] Other polymers include, for example, thermoplastic polyesters and their copolymers such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, and polyarylate; styrene polymers such as polystyrene, high-impact polystyrene (HIPS), acrylonitrile-styrene copolymer (AS resin), acrylonitrile-styrene-acrylic rubber copolymer (ASA resin), and acrylonitrile-ethylene propylene rubber-styrene copolymer (AES resin); polyolefins such as polyethylene and polypropylene; polyamides; polyimides; polyetherimides; polyurethanes; polyphenylene ethers; polyphenylene sulfides; polysulfones; and polymethacrylates. These polymers may be present individually or in any combination and ratio.

[0064] Examples of additives include heat stabilizers, antioxidants, mold release agents, weathering agents (UVA, HALS), flame retardants, antistatic agents, antifogging agents, lubricants, antiblocking agents, flow improvers, plasticizers, dispersants, antibacterial agents, dyes, and pigments. Note that the product may contain only one additive, or two or more additives in any combination and ratio.

[0065] (Physical properties) The polycarbonate resin layer (A) preferably has a glass transition temperature of 120°C or higher, measured in accordance with JIS K7121:2012, from the viewpoint of heat resistance, more preferably 130°C or higher, and more preferably 135°C or higher. On the other hand, from the viewpoint of moldability, it is preferably 200°C or lower, more preferably 190°C or lower, and more preferably 180°C or lower.

[0066] <Polycarbonate resin layer (B)> The aforementioned polycarbonate resin layer (B) is a layer containing polycarbonate B-1 as the main polymer component.

[0067] (Polycarbonate B-1) Polycarbonate B-1 is a polycarbonate containing 50% by mass or more of the structural unit (c) represented by the following formula (3). From the viewpoint of moldability, polycarbonate B-1 preferably contains 50% by mass or more of the structural unit (c) represented by the following formula (3), more preferably 60% by mass or more, of which 70% by mass or more, of which 80% by mass or more, and of which 90% by mass or more, and may contain 100% by mass. Furthermore, it is preferable that polycarbonate B-1 is a polymer different from the main polymer of the polycarbonate resin (A).

[0068] TIFF2026066580000014.tif33170

[0069] The viscosity-average molecular weight (Mv) of the polycarbonate B-1 is preferably 32,000 or less, more preferably 30,000 or less, and more preferably 28,000 or less, from the viewpoint of moldability. On the other hand, if the viscosity-average molecular weight (Mv) of the polycarbonate B-1 is too small, the mechanical strength, such as impact resistance, will decrease, so it is preferably 12,000 or more, more preferably 14,000 or more, and more preferably 15,000 or more. The glass transition temperature of polycarbonate B-1, as measured in accordance with JIS K7121:2012, is preferably 120°C or higher, more preferably 130°C or higher, and even more preferably 140°C or higher, from the viewpoint of heat resistance. On the other hand, if the glass transition temperature of polycarbonate B-1 is too high, molding becomes difficult, so it is preferably 200°C or lower, more preferably 180°C or lower, and even more preferably 160°C or lower. It is preferable that the polycarbonate B-1 does not have a crystal melting temperature measured in accordance with JIS K7121:2012, in order to improve mechanical strength, such as impact resistance. The polycarbonate B-1 has an apparent viscosity at 280°C at a shear rate of 100 (1 / s) of 80 Pa·s or higher, more preferably 90 Pa·s or higher, and more preferably 100 Pa·s or higher, from the viewpoint of impact resistance. On the other hand, from the viewpoint of moldability, it is preferably 1,500 Pa·s or lower, more preferably 1,200 Pa·s or lower, and more preferably 1,000 Pa·s or lower.

[0070] (Other ingredients) The polycarbonate resin layer (B) may contain components other than polycarbonate B-1 as needed. Examples include other polycarbonates, other polymers, and additives.

[0071] Examples of polycarbonates other than polycarbonate B-1 include polycarbonates containing structural units (a) represented by formula (1) or structural units (b) represented by formula (2), or both (a) and (b). For example, examples include polycarbonates obtained by copolymerizing bisphenol C and bisphenol TMC, and polycarbonates containing bisphenol C. However, the examples are not limited to these. When recycling the laminated film of the present invention, it is assumed that the entire laminated film will be melted and used as a raw material for the polycarbonate resin layer (B). In that case, polycarbonates other than polycarbonate B-1 will be contained in the polycarbonate resin layer (B).

[0072] Other polymers include, for example, thermoplastic polyesters and their copolymers such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, and polyarylate; styrene polymers such as polystyrene, high-impact polystyrene (HIPS), acrylonitrile-styrene copolymer (AS resin), acrylonitrile-styrene-acrylic rubber copolymer (ASA resin), and acrylonitrile-ethylene propylene rubber-styrene copolymer (AES resin); polyolefins such as polyethylene and polypropylene; polyamides; polyimides; polyetherimides; polyurethanes; polyphenylene ethers; polyphenylene sulfides; polysulfones; and polymethacrylates. These polymers may be present individually or in any combination and ratio.

[0073] Examples of additives include heat stabilizers, antioxidants, mold release agents, lightfastness agents (HALS), flame retardants, antistatic agents, antifogging agents, lubricants, antiblocking agents, flow improvers, plasticizers, dispersants, antibacterial agents, dyes, and pigments. Note that the product may contain only one additive, or two or more additives in any combination and ratio.

[0074] (Content percentage) In the polycarbonate resin layer (B), the content of polycarbonate B-1 is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, and may even be 100% by mass, from the viewpoint of maintaining the properties of polycarbonate.

[0075] (Physical properties) The polycarbonate resin layer (B) preferably has a glass transition temperature of 100°C or higher, measured in accordance with JIS K7121:2012, from the viewpoint of heat resistance, more preferably 120°C or higher, and more preferably 140°C or higher. On the other hand, from the viewpoint of moldability, it is preferably 200°C or lower, more preferably 180°C or lower, and more preferably 160°C or lower.

[0076] <Layer thickness> The thickness of each polycarbonate resin layer (A) is preferably 1 μm or more, more preferably 3 μm or more, and more preferably 5 μm or more, from the viewpoint of improving the surface hardness of the film. On the other hand, from the viewpoint of improving mechanical strength, such as impact resistance, it is preferably 9 mm or less, more preferably 5 mm or less, and more preferably 1 mm or less.

[0077] The thickness of the polycarbonate resin layer (B) is preferably 1 μm or more from the viewpoint of impact resistance, more preferably 10 μm or more, and more preferably 20 μm or more. On the other hand, from the viewpoint of surface hardness, it is preferably 9 mm or less, more preferably 5 mm or less, and more preferably 3 mm or less.

[0078] The layer thickness ratio of the polycarbonate resin layer (A) (each layer) to the polycarbonate resin layer (B) is preferably 1:99 to 99:1 from the viewpoint of surface hardness and heat resistance, and more preferably 5:95 to 50:50, of which 10:90 to 40:60, and of which 15:85 to 30:70.

[0079] The thickness of the laminated film of the present invention is preferably 0.01 mm or more, more preferably 0.03 mm or more, and more preferably 0.05 mm or more, from the viewpoint of moldability. On the other hand, from the viewpoint of moldability, it is preferably 10 mm or less, more preferably 8 mm or less, and more preferably 5 mm or less.

[0080] <Physical properties of the laminated film of the present invention> The laminated film of the present invention may have the following physical properties.

[0081] (Surface hardness) The laminated film of the present invention conforms to JIS K5600-5-4:1999, and preferably has a pencil hardness of HB or higher, more preferably F or higher, and even more preferably H or higher, as measured under a 750g load for a 100μm thick film.

[0082] (Puncture shock) The laminated film of the present invention preferably has a puncture impact strength of 2.0 J or more, measured at a temperature of 23°C for a 100 μm thick film, in accordance with JIS K7124-2:1999, more preferably 2.2 J or more, and even more preferably 2.3 J or more.

[0083] (Heat resistance) The laminated film of the present invention preferably has a heat shrinkage rate of less than 0.3% when measured under test conditions of 150°C for 30 minutes for a 100 μm thick film, in accordance with JIS K7133:1999, more preferably less than 0.1%, and even more preferably less than 0.05%.

[0084] (transparency) The laminated film of the present invention preferably has a total light transmittance of 80% or more for a 100 μm thick film, measured in accordance with JIS K7361:1997, more preferably 85% or more, and even more preferably 90% or more.

[0085] <Method for manufacturing the laminated film of the present invention> The laminated film of the present invention can be manufactured by various methods, but it is preferable to manufacture it by the following method, for example. The laminated film of the present invention can be manufactured by a co-extrusion method, in which the raw materials for polycarbonate resin layer (A) and polycarbonate resin layer (B) are melted in one or more extruders, extruded from a flat die or annular die, and then rapidly cooled to form a flat or annular unstretched film. A more specific example is a manufacturing method in which the raw materials for polycarbonate resin layer (A) and polycarbonate resin layer (B) are each fed into an extruder, melted, distributed in a distribution block, multilayered in a co-extrusion T-die, the molten film is extruded, and cooled on a cooling roll to produce the laminated film of the present invention.

[0086] <Explanation of terms and phrases> In this invention, the term "film" includes "sheets," and the term "sheet" includes "film."

[0087] In this invention, when "α~β" (where α and β are arbitrary numbers) is written, unless otherwise specified, it means "α or greater and β or less," and also includes the meaning of "preferably greater than α" or "preferably less than β." Furthermore, when written as "α or greater" or "α ≤" (where α is any number), unless otherwise specified, it includes the meaning of "preferably greater than α," and when written as "β or less" or "≤β" (where β is any number), unless otherwise specified, it also includes the meaning of "preferably less than β." [Examples]

[0088] The following describes an example of an embodiment of the present invention. However, the present invention is not limited to the embodiment described below.

[0089] <Evaluation Method> (1) Glass transition temperature (Tg) and crystal melting temperature The glass transition temperature and crystal melting temperature of the polymer and polycarbonate resin layers were measured in accordance with JIS K7121:2012. A differential scanning calorimeter (DSC) manufactured by PerkinElmer was used for the measurements. The glass transition temperature and crystal melting temperature of the polymer were determined from the inflection point and endothermic peak top temperature of the DSC curve of the polymer pellet detected during the reheating process at a temperature range of 30 to 300°C and a heating rate of 10°C / min. For the polycarbonate resin layer, a film of only the resin layer was taken and measured in the same manner as the polymer.

[0090] (2) Viscosity average molecular weight (Mv) The polymer was dissolved in methylene chloride (concentration 6.0 g / L), and the intrinsic viscosity (intrinsic viscosity) [η] (unit dL / g) at 20°C was determined using an Ubbelohde viscosity tube (manufactured by Moritomo Rika Kogyo Co., Ltd.). The viscosity-average molecular weight (Mv) of the polymer was then calculated from Schnell's viscosity equation (see below). η = 1.23 × 10 -4 Mv 0.83

[0091] (3) Apparent viscosity The apparent viscosity of the polymer at 280°C with a shear rate of 100 (1 / s) was measured using a high-efficiency flow tester (manufactured by Shimadzu Corporation) equipped with a nozzle of φ1 × L10 mm.

[0092] (4) Surface hardness The surface hardness of the obtained laminated films (samples) was measured using a pencil hardness tester (manufactured by Yasuda Seiki Co., Ltd.) under a 750g load condition for a 100μm thick film, in accordance with JIS K5600-5-4:1999. A pencil hardness of HB or higher was evaluated as "A (Pass)", a hardness of B or higher but less than HB was evaluated as "B (Fail)", and a hardness of less than B was evaluated as "C (Fail)".

[0093] (5) Impact resistance The impact resistance of the obtained laminated film (sample) was measured by puncture impact strength in accordance with JIS K7124-2:1999. Each laminated film (sample) with a thickness of 100 μm was measured using a high-speed puncture impact tester Hydroshot HITS-P10 (Shimadzu Corporation) at a temperature of 23°C, with a punching diameter of 0.5 inches and a test speed of 3 m / sec. Under a temperature of 23°C, a puncture impact strength of 2.0J or higher was evaluated as "A (Pass)", a strength of 1.0J or higher but less than 2.0J was evaluated as "B (Fail)", and a strength of less than 1.0J was evaluated as "C (Fail)".

[0094] (6) Heat resistance The heat resistance of the obtained laminated film (sample) was measured by cutting it into a 12cm x 12cm size and measuring the heat shrinkage rate (%) in MD under test conditions of 150°C x 30 minutes for a 100μm thick film, in accordance with JIS K7133:1999. A heat shrinkage rate of less than 0.3% was evaluated as "A (Pass)", a rate of 0.3% or more but less than 1.0% was evaluated as "B (Fail)", and a rate of 1.0% or more was evaluated as "C (Fail)".

[0095] (7) Transparency The transparency of the obtained laminated film (sample) was measured using a haze meter to determine the total light transmittance of a 100 μm thick film, in accordance with JIS K7361:1997.

[0096] <Material> Polymer (A)-1: A polycarbonate copolymer (BPC / BP-TMC copolymer PC) synthesized according to Preparation Example 1 below, using bisphenol C and bisphenol TMC as copolymer raw materials, with a bisphenol C:bisphenol TMC ratio of 50:50 (mass ratio). Apparent viscosity at 280°C is 1.2 × 10⁻¹⁰ at Tg 163°C, Mv 23,000, and shear rate 100 (1 / s). 3 Pa·s It contains 50% by mass of the constituent unit (a) represented by formula (1) and 50% by mass of the constituent unit (b) represented by formula (2). The constituent unit (a) represented by formula (1) is the constituent unit represented by formula (5). The structural unit (b) represented by the formula (2) is the structural unit represented by the formula (7).

[0097] Polymer (A)-2: Bisphenol C type polycarbonate ("Novarex MF7526" manufactured by Mitsubishi Engineering Plastics Corporation) (bisphenol C type PC) Tg 120°C, Mv 25,500, apparent viscosity at 280°C at a shear rate of 100 (1 / s) 8.0×10 2 Pa·s It contains 100% by mass of the structural unit (b) represented by the formula (2).

[0098] Polymer (A)-3: Bisphenol A type polycarbonate ("Iupilon S-2000" manufactured by Mitsubishi Engineering Plastics Corporation) (bisphenol A type PC) Tg 145°C, Mv 22,300, apparent viscosity at 280°C at a shear rate of 100 (1 / s) 9.1×10 2 Pa·s It contains 100% by mass of the structural unit (c) represented by the formula (3).

[0099] [Preparation Example 1] In a 150 ml glass reactor equipped with a reactor stirrer, a reactor heating device, and a reactor pressure regulating device, 58.36 g (about 0.228 mol) of 2,2-bis(4-hydroxy-3-methylphenyl)propane (BPC) (manufactured by Honshu Chemical Industry Co., Ltd.), 58.36 g (0.188 mol) of 4,4'-(3,3,5-trimethylcyclohexylidene)bisphenol (BP-TMC) (manufactured by Honshu Chemical Industry Co., Ltd.), 93.93 g (about 0.438 mol) of diphenyl carbonate (DPC), and a 0.4% by mass aqueous solution of cesium carbonate as a catalyst were added so that the amount of cesium carbonate was 1.5 μmol per 1 mol of the total dihydroxy compound to prepare a raw material mixture.

[0100] Next, the pressure inside the glass reactor was reduced to approximately 50 Pa (0.38 Torr), and then the pressure was restored to atmospheric pressure with nitrogen. This process was repeated three times to purge the inside of the reactor with nitrogen. After nitrogen purging, the external temperature of the reactor was raised to 220°C, and the internal temperature of the reactor was gradually increased to dissolve the mixture. Then, the stirrer was rotated at 100 rpm. While distilling off the phenol produced as a by-product by the oligomerization reaction of the dihydroxy compound and DPC taking place inside the reactor, the pressure inside the reactor was reduced from an absolute pressure of 101.3 kPa (760 Torr) to 13.3 kPa (100 Torr) over 40 minutes.

[0101] Next, the reactor pressure was maintained at 13.3 kPa, and the transesterification reaction was carried out for 80 minutes while further distilling off the phenol. After that, the external temperature of the reactor was raised to 250°C, and the internal pressure of the reactor was reduced from 13.3 kPa (100 Torr) to 399 Pa (3 Torr) over 40 minutes to remove the distilled phenol from the system. Furthermore, the external temperature of the reactor was raised to 285°C, and the internal pressure of the reactor was reduced to 30 Pa (approximately 0.2 Torr) to carry out the polycondensation reaction. The polycondensation reaction was terminated when the reactor stirrer reached a predetermined stirring power.

[0102] Next, the reactor was repressurized to an absolute pressure of 101.3 kPa using nitrogen, and then increased to a gauge pressure of 0.2 MPa. Polycarbonate was then extracted in strand form from the bottom of the reactor to obtain the stranded polycarbonate, which was then pelletized using a rotary cutter to obtain polycarbonate (A)-1.

[0103] <Examples 1-3, Comparative Examples 1-4> As shown in Table 1, polymers (A)-1 to (A)-3, which serve as raw materials for the surface and back layers respectively, were introduced into a φ32 mm extruder and melted at 280°C. Polymers (A)-1 to (A)-3, which serve as raw materials for the middle layer, were introduced into a φ40 mm extruder and melted at 280°C. The mixture was then distributed in a distribution block and multilayered in a co-extrusion T-die. The molten film was extruded so that the layer thickness ratio of the surface / middle / back layers was 2 / 6 / 2, and the film was cooled on a cooling roll at 140°C to produce a 100 μm thick laminated film (sample).

[0104] [Table 1]

[0105] In all three Examples 1 to 3, the polycarbonate resin layers, which are the front and back layers, consisted solely of polycarbonate (A)-1, which is copolymerized with bisphenol C and bisphenol TMC, or of the aforementioned polycarbonate (A)-1 and polycarbonate (A)-2 containing bisphenol C. These layers contained the structural units (a) and (b) represented by formulas (1) and (2), and each contained at least 40% by mass of structural unit (a) represented by formula (1) and at least 10% by mass of structural unit (b) represented by formula (2) based on 100% by mass of the total amount of polycarbonate contained in the polycarbonate resin layer. It was found that all of these layers exhibited excellent surface hardness and heat resistance. Furthermore, in all of Examples 1 to 3, the middle layer consisted of type A polycarbonate (A)-3 made from bisphenol A, and the layer was made of a polycarbonate polymer mainly composed of 50% by mass or more of the structural unit (c) represented by formula (3), and it was found that all of these exhibited excellent impact resistance.

[0106] In contrast, Comparative Example 1 had a polycarbonate resin layer consisting of a front and back layer made of polycarbonate (A)-2 containing bisphenol C, and did not contain the structural unit (a) represented by formula (1). As a result, it had low heat resistance and poor dimensional stability. Comparative Example 2 had low surface hardness because both the front and back layers and the middle layer, which are polycarbonate resin layers, were made of type A polycarbonate (A)-3 made from bisphenol A. Comparative Example 3 had inferior impact resistance because both the front and back layers and the middle layer, which are polycarbonate resin layers, were made of polycarbonate (A)-2 containing bisphenol C. Comparative Example 4 consisted of polycarbonate (A)-1, which is a copolymer of bisphenol C and bisphenol TMC, for both the front and back layers and the middle layer. However, the middle layer did not have polycarbonate containing 50% by mass or more of the structural unit (c) represented by formula (3) as its main polymer component, resulting in inferior impact resistance.

[0107] From the above examples and comparative examples, as well as the test results conducted by the inventors to date, it has been found that if the polycarbonate resin layers, which are the front and back layers, contain a total of 40% by mass or more of structural unit (a) represented by formula (1) and a total of 10% by mass or more of structural unit (b) represented by formula (2), based on 100% by mass of the total amount of polycarbonate contained in the polycarbonate resin layer, then the laminated film can possess both surface hardness and heat resistance. Furthermore, it was found that if the intermediate polycarbonate resin layer is a polymer mainly composed of polycarbonate containing 50% by mass or more of the structural unit (c) represented by formula (3), the laminated film can be made impact resistant.

[0108] By including the constituent units represented by formulas (1) and (2), the glass transition temperature (Tg) of the polycarbonate resin layer (A) is increased while maintaining its surface hardness. Furthermore, by laminating a polycarbonate resin layer (B) containing the constituent units represented by formula (3), which have excellent heat resistance and impact resistance, the surface hardness, heat resistance, and impact resistance can be improved. In this case, the constituent unit represented by formula (1) is R x and R yBecause it has the characteristic of having an alkyl group with 1 to 6 carbon atoms, it is thought that it can obtain the same effects as bisphenol C. Furthermore, since the constituent unit represented by formula (2) has structural characteristics that suppress the mobility of the molecular chain, it is thought that it can achieve the same effect as bisphenol TMC. [Industrial applicability]

[0109] The laminated film of the present invention exhibits unique sliding properties and excellent impact resistance, making it extremely useful for automotive, card, building, display, and electrical / electronic applications.

Claims

1. A laminated film having a polycarbonate resin layer (B) containing polycarbonate as the main polymer component, and having a polycarbonate resin layer (A) containing polycarbonate as the main polymer component on at least one of its outermost surfaces, The polycarbonate resin layer (A) contains, in total, 40% by mass or more of structural units (a) represented by the following formula (1) and 10% by mass or more of structural units (b) represented by the following formula (2), based on 100% by mass of the total amount of polycarbonate contained in the polycarbonate resin layer (A). The polycarbonate resin layer (B) comprises polycarbonate B-1 as the main component polymer, and the polycarbonate B-1 is a polycarbonate containing 50% by mass or more of the structural unit (c) represented by the following formula (3), in a laminated film. [In formula (1), X is at least one selected from a single bond, an oxygen atom, a sulfur atom, and a divalent organic group. R ｘ and R ｙ These are each an alkyl group having 1 to 6 carbon atoms. In formula (2), Y is at least one selected from a single bond, an oxygen atom, a sulfur atom, and a divalent organic group.

2. The laminated film according to claim 1, wherein in formula (1), X is a divalent organic group represented by the following formula (4). [In formula (4), R １ and R ２ Each of these is independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 24 carbon atoms. １ and R ２ These may be bonded to each other to form a ring. * represents a bond to the benzene ring in formula (1).

3. In the above formula (4), R １ and R ２ The laminated film according to claim 2, wherein all of them are methyl groups.

4. The laminated film according to claim 1, wherein formula (1) is represented by the following formula (5).

5. The laminated film according to claim 1, wherein in formula (2), Y is a divalent organic group represented by the following formula (6). [In formula (6), R ３ , R ４ are each independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 24 carbon atoms. R ３ and R ４ may be bonded to each other to form a ring. * is a bond to the benzene ring in formula (2).]

6. The laminated film according to claim 1, wherein formula (2) is represented by the following formula (7).

7. The laminated film according to claim 1, wherein the mass ratio of structural unit (a) to structural unit (b) in the polycarbonate resin layer (A) is 90:10 to 40:

60.

8. The laminated film according to claim 1, wherein the polycarbonate resin layer (A) has a glass transition temperature of 120°C or more and 200°C or less, as measured in accordance with JIS K7121:2012.

9. The laminated film according to claim 1, wherein the polycarbonate resin layer (B) has a glass transition temperature of 100°C or more and 200°C or less, as measured in accordance with JIS K7121:2012.

10. The laminated film according to claim 1, wherein the thickness ratio of the polycarbonate resin layer (A) to the polycarbonate resin layer (B) is 1:99 to 99:

1.

11. The laminated film according to claim 1, wherein the thickness is 0.01 mm or more and 10 mm or less.

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