Copolymer, method for producing copolymer, and resin composition containing copolymer

Abstract

Provided are: a copolymer which is capable of suppressing coloring even after heating; and a method for producing the copolymer. A copolymer containing a structural unit (A) derived from 1, 1-dicyanoethylene and a structural unit (B) derived from a compound represented by general formula (I) CH2 = CR1R2 (I), characterized in that the copolymer contains the following four triad structures (U-1)-(U-4) comprising the structural unit (A) and the structural unit (B), the total content of (U-2) and (U-3) in the total amount of the four triad structures (A)-(A)-(A)... (U-1) (A)-(A)-(B)... (U-2) (B)-(A)-(A)... (U-3) (B)-(A)-(B)... (U-4) is 5.5 mol% or less.

Description

Technical Field

[0001] The present invention relates to a copolymer containing a structural unit derived from 1,1-dicyanoethylene and a structural unit derived from a specific polymerizable monomer in a specific arrangement, a method for producing the copolymer, a resin composition containing the copolymer, and the like. Background Art

[0002] Films using copolymers obtained by free radical polymerization of 1,1-dicyanoethylene and polymerizable monomers have excellent transparency and are therefore suitable for use in various materials such as optical components, lighting components, sign components, and decorative components (e.g., Patent Document 1). Research on polymers using the above-mentioned 1,1-dicyanoethylene is in vogue, and, for example, Non-Patent Document 1 describes an analysis method for copolymers of 1,1-dicyanoethylene and styrene.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 01-103614

[0006] Non-patent literature

[0007] Non-patent document 1: Polymer, 1988, 29, 144-151 Summary of the invention

[0008] Problems to be solved by the invention

[0009] As described above, a film using a copolymer obtained by radical polymerization of 1,1-dicyanoethylene and a polymerizable monomer has excellent transparency, but has a problem in that the copolymer is colored when heated, thereby impairing the appearance.

[0010] The present invention is completed in view of the above-mentioned existing problems, and its subject is to provide a copolymer and a method for producing the same which can suppress coloration even after heating. In addition, the subject of the present invention is to provide a resin composition containing the copolymer, and a molded product and a film using the copolymer.

[0011] Methods used to solve problems

[0012] The present inventors have conducted research and found that by free radical polymerization of 1,1-dicyanoethylene and a specific polymerizable monomer at a relatively low temperature and at a specific input ratio, the structural units derived from 1,1-dicyanoethylene and the structural units derived from the polymerizable monomer are polymerized in a specific arrangement. Based on this finding, further research was conducted and found that by controlling the arrangement of each monomer, a copolymer capable of suppressing coloration even after heating can be obtained, thereby completing the present invention.

[0013] That is, the present invention provides the following [1] to

[10] .

[0014] [1] A copolymer comprising a structural unit (A) derived from 1,1-dicyanoethylene and a structural unit (B) derived from a compound represented by the following general formula (I),

[0015] CH 2 =CR 1 R 2 (I)

[0016] It is characterized in that

[0017] The copolymer contains the following four triad structures (U-1) to (U-4) composed of the structural unit (A) and the structural unit (B),

[0018] (A)-(A)-(A) … (U-1)

[0019] (A)-(A)-(B) … (U-2)

[0020] (B)-(A)-(A) … (U-3)

[0021] (B)-(A)-(B) … (U-4)

[0022] The content of (U-2) and (U-3) in the total amount of the above four types of triad structures is 5.5 mol % or less.

[0023] (In the general formula (I), R 1 is one or more selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group and a halogen atom,

[0024] R 2 is one or more selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a halogen atom and a halogenated alkyl group.

[0025] [2] The copolymer according to [1] above, wherein the content of the (U-1) is 1.8 mol % or less in the total amount of the four triad structures.

[0026] [3] The copolymer according to [1] or [2] above, wherein the content of the structural unit (A) in the total amount of the copolymer is 30 to 55 mol %.

[0027] [4] The copolymer according to any one of [1] to [3] above, wherein the compound represented by the general formula (I) is one or more selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, isobutylene, 1-hexene, propylene and ethylene.

[0028] [5] A method for producing a copolymer, which is a method for producing the copolymer described in any one of [1] to [4] above, wherein the polymerization temperature is below 45°C, the amount of the compound represented by the general formula (I) added is 0.80 to 3.5 equivalents relative to the amount of 1,1-dicyanoethylene added, and the production is carried out in the presence of a free radical polymerization initiator.

[0029] [6] A resin composition comprising the copolymer according to any one of [1] to [4] above.

[0030] [7] A molded product using the copolymer described in any one of [1] to [4] or the resin composition described in [6] above.

[0031] [8] A film using the copolymer described in any one of [1] to [4] or the resin composition described in [6], wherein the difference between the yellowness before heating and the yellowness after heating at 140° C. for 1 hour under normal pressure is 2.5% or less.

[0032] [9] A conductive film comprising a conductive layer stacked on the film according to [8] above.

[0033]

[10] A thin film capacitor comprising the thin film described in [8] above or the conductive thin film described in claim 9.

[0034] Effects of the Invention

[0035] According to the present invention, a copolymer capable of suppressing coloration even after heating and a method for producing the same can be provided. In addition, according to the present invention, a resin composition containing the copolymer, and a molded product and a film using the copolymer can be provided. DETAILED DESCRIPTION

[0036] [Copolymer]

[0037] The copolymer of the present invention is a copolymer containing a structural unit (A) derived from 1,1-dicyanoethylene and a structural unit (B) derived from a compound represented by the following general formula (I).

[0038] CH 2 =CR 1 R 2 (I)

[0039] It is characterized in that

[0040] The copolymer contains the following four triad structures (U-1) to (U-4) composed of the structural unit (A) and the structural unit (B),

[0041] (A)-(A)-(A) … (U-1)

[0042] (A)-(A)-(B) … (U-2)

[0043] (B)-(A)-(A) … (U-3)

[0044] (B)-(A)-(B) … (U-4)

[0045] The total content of (U-2) and (U-3) in the total amount of the above four types of triad structures is 5.5 mol % or less.

[0046] (In the general formula (I), R 1 is one or more selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group and a halogen atom,

[0047] R 2 is one or more selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a halogen atom and a halogenated alkyl group.

[0048] In the present invention, the "triad structure" refers to a structure in which three structural units (A) derived from 1,1-dicyanoethylene and three structural units (B) derived from the compound represented by the above general formula (I) are connected.

[0049] In addition, "(A)-(A)-(A)", which is one of the above-mentioned four triad structures, refers to a triad structure in which three structural units (A) derived from 1,1-dicyanoethylene are continuously bonded, and "(A)-(A)-(B)" refers to a triad structure in which two structural units (A) derived from 1,1-dicyanoethylene are continuously bonded and then bonded to a structural unit (B) derived from the compound represented by the above-mentioned general formula (I), and the other triad structures have the same meaning.

[0050] In the present invention, the amounts of four triad structures (U-1) to (U-4) are specified. The amount of the triad structure (U-1) refers to "the content (mol %) of (A) bonded between two (A)s in the structure of (A)-(A)-(A) constituting (U-1)". Similarly, the content of the triad structure (U-2) refers to "the content (mol %) of (A) bonded between (A) and (B) in the structure of (A)-(A)-(B) constituting (U-2)". The contents of other triad structures have the same meaning.

[0051] It should be noted that the contents of the triad structures (U-1) to (U-4) in the present invention can be adjusted by 13 C-NMR can be measured, and specifically, it can be measured by the method described in the Examples.

[0052] The present invention is characterized in that the total content of (U-2) and (U-3) in the total amount of the above-mentioned four triad structures is 5.5 mol% or less. When the total content of the above-mentioned (U-2) and (U-3) is 5.5 mol% or less, the amount of the arrangement that causes coloration due to heat, specifically the continuous arrangement of (A), can be suppressed to a small extent, so that the molded product using the copolymer of the present invention can suppress coloration even after heating.

[0053] From the viewpoint of effectively suppressing coloration, the total content of (U-2) and (U-3) in the total amount of the above-mentioned four triad structures is 5.5 mol% or less, preferably 5.2 mol% or less, preferably 5.0 mol% or less, preferably 4.8 mol% or less, and further preferably 4.6 mol% or less. Usually, the lower limit is 0.5 mol% or more, but it can also be less than it, and is preferably 0.1 mol% or more.

[0054] The total content of (U-2) and (U-3) can be adjusted by controlling the amount of monomers added at a relatively low temperature of 50° C. or lower.

[0055] In addition, in the present invention, the content of the above-mentioned (U-1) in the total amount of the above-mentioned 4 triad structures is preferably 1.8 mol% or less. When the content of the above-mentioned (U-1) is below the above-mentioned upper limit, the continuous arrangement of (A) in the copolymer decreases, and therefore, as a result, the coloring after heating of the molded product using the copolymer of the present invention can be further suppressed. From the above viewpoint, the content of the above-mentioned (U-1) in the total amount of the above-mentioned 4 triad structures is preferably 1.7 mol% or less, more preferably 1.5 mol% or less, and further preferably 0.5 mol% or less.

[0056] <Structural unit derived from 1,1-dicyanoethylene (A)>

[0057] The copolymer of the present invention contains a structural unit (A) derived from 1,1-dicyanoethylene. Since 1,1-dicyanoethylene provides a highly transparent copolymer by radical polymerization, the copolymer of the present invention can be suitably used for molded products and the like that require transparency.

[0058] 1,1-Dicyanoethylene can be produced by the production methods described in J. Am. Chem. Soc., 1989, 111, 9078-9081 and US Patent Application Publication No. 2476270.

[0059] <Structural unit (B) derived from the compound represented by general formula (I)>

[0060] The copolymer of the present invention contains a structural unit (B) derived from a compound represented by the following general formula (I).

[0061] CH 2 =CR 1 R 2 (I)

[0062] In the general formula (I), R 1 is one or more selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group and a halogen atom,

[0063] R 2 is at least one selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a halogen atom and a halogenated alkyl group.

[0064] In the general formula (I), R 1 is at least one selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group and a halogen atom.

[0065] As R 1 The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, heptyl, octyl, decyl and dodecyl.

[0066] As R 1 The cycloalkyl group is preferably a cycloalkyl group having 3 to 12 carbon atoms, and examples thereof include cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

[0067] As R 1 The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and examples thereof include phenyl, tolyl, xylyl and naphthyl.

[0068] As R 1 The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms, and examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy and tert-butoxy.

[0069] As R 1 The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0070] However, from the viewpoint of suppressing the coloration of the molded product using the copolymer of the present invention after heating, R 1 A hydrogen atom and an alkyl group having 1 to 6 carbon atoms are preferred, a hydrogen atom and an alkyl group having 1 to 4 carbon atoms are more preferred, and a hydrogen atom and a methyl group are further preferred.

[0071] In the general formula (I), R 2is at least one selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a halogen atom and a halogenated alkyl group.

[0072] As R 2 The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl and n-hexyl.

[0073] As R 2 The alkenyl group represented by is preferably an alkenyl group having 2 to 12 carbon atoms, and examples thereof include vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl, pentenyl, isoprenyl, hexenyl (such as cis-3-hexenyl) and cyclohexenyl.

[0074] As R 2 The cycloalkyl group is preferably a cycloalkyl group having 3 to 12 carbon atoms, and examples thereof include cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

[0075] As R 2 The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and examples thereof include phenyl, tolyl, xylyl and naphthyl.

[0076] As R 2 The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0077] In addition, as R 2 The haloalkyl group is preferably a haloalkyl group having 1 to 12 carbon atoms, and more preferably a haloalkyl group having 1 to 6 carbon atoms. Examples of the halogen atom constituting the haloalkyl group include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0078] However, from the viewpoint of suppressing the coloration of the molded product using the copolymer of the present invention after heating, R 2 It is preferably one selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group and an aryl group, more preferably an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, and still more preferably an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms.

[0079] More specifically, from the viewpoint of suppressing coloration, the compound represented by the general formula (I) is more preferably one or more selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, isobutylene, 1-hexene, propylene and ethylene. By using these compounds, discoloration can be more effectively suppressed.

[0080] The compound represented by the above general formula (I) can be easily obtained from commercial products, or can be produced by a known method.

[0081] <Content of each structural unit in the copolymer>

[0082] The content of the structural unit (A) in the copolymer of the present invention is preferably 30 to 55 mol %, more preferably 40 to 53 mol %, and even more preferably 48 to 51 mol %.

[0083] On the other hand, the content of the structural unit (B) is preferably 20 to 80 mol %, preferably 45 to 70 mol %, more preferably 47 to 60 mol %, further preferably 49 to 52 mol %, further preferably 50 to 51 mol %.

[0084] When the content of each structural unit is within the above range, a molded product using the copolymer of the present invention is unlikely to be colored even after heating.

[0085] It should be noted that the content of the above-mentioned structural units can be 1 H-NMR can be measured, and specifically, it can be measured by the method described in Examples.

[0086] <Other structural units>

[0087] The copolymer of the present invention may also contain structural units derived from other monomers in addition to the structural unit (A) derived from 1,1-dicyanoethylene and the structural unit (B) derived from the compound represented by the above general formula (I). The other structural units are not particularly limited, and examples thereof include vinyl acetate, vinyl propionate, methyl acrylate, ethyl acrylate, and butyl acrylate.

[0088] When the copolymer of the present invention contains a structural unit derived from other monomers, the content of the structural unit in the copolymer is preferably 20 mol % or less, more preferably 10 mol % or less, and even more preferably 5 mol % or less.

[0089] [Method for producing copolymer]

[0090] The method for producing the copolymer of the present invention is not particularly limited, but the copolymer is preferably produced by the method for producing the copolymer of the present invention in which the polymerization temperature is 45° C. or lower and the copolymer is produced in the presence of a radical initiator.

[0091] By setting the polymerization temperature to 45° C. or less, it is easy to adjust the content of (U-2) and (U-3) in the total amount of the above four triad structures to 5.5 mol % or less. From the viewpoint of adjusting the content of (U-2) and (U-3), the polymerization temperature is preferably 44° C. or less, more preferably 43° C. or less, and even more preferably 40° C. or less.

[0092] From the viewpoint of polymerization rate and productivity, the polymerization temperature is preferably 10° C. or higher, more preferably 20° C. or higher, and further preferably 30° C. or higher.

[0093] <Radical polymerization initiator>

[0094] In the production of the copolymer of the present invention, it is preferably produced in the presence of a radical polymerization initiator. By using a radical polymerization initiator, the total content of (U-2) and (U-3) in the total amount of the triad structure can be easily adjusted.

[0095] As the free radical polymerization initiator that can be used in the present invention, for example, there can be mentioned azo compounds such as azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate; inorganic peroxides such as sodium persulfate, potassium persulfate, hydrogen peroxide; organic peroxides such as tert-butyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide; redox initiators composed of a combination of an oxidant and a reductant such as hydrogen peroxide and an iron (II) salt, a persulfate and sodium bisulfite, etc. These can be used alone or in combination of two or more.

[0096] As described above, the copolymer of the present invention can be easily adjusted in the total content of (U-2) and (U-3) in the total amount of the triad structure by free radical polymerization at low temperature. Therefore, among these free radical polymerization initiators, azo compounds such as azobisisobutyronitrile and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), redox initiators, etc., which are easy to use at low temperatures, are preferred.

[0097] The amount of the radical polymerization initiator used is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and even more preferably 0.08 to 3 parts by mass, based on 100 parts by mass of all monomers used as raw materials of the copolymer.

[0098] <Ratio of input amount when producing copolymer>

[0099] In the production of the copolymer of the present invention, the amount of the compound represented by the general formula (I) is preferably 0.80 equivalents or more, more preferably 0.85 equivalents or more, and further preferably 0.90 equivalents or more relative to the amount of 1,1-dicyanoethylene. Generally, from the viewpoint of suppressing the production cost, it is preferably 3.5 equivalents or less. When the amount of the compound represented by the general formula (I) relative to the amount of 1,1-dicyanoethylene is greater than the lower limit, it is easy to adjust the total content of (U-2) and (U-3) in the total amount of the triad structure, and as a result, it is possible to suppress the discoloration of the molded product using the copolymer after heating.

[0100] In the production of the copolymer of the present invention, from the viewpoint of suppressing ionic polymerization, it is preferred that the amount of water contained in 1,1-dicyanoethylene is low. The amount of water contained in 1,1-dicyanoethylene is preferably 10000 ppm or less, more preferably 1000 ppm or less, further preferably 500 ppm or less, further preferably 200 ppm or less, further preferably 100 ppm or less. When the amount of water contained in 1,1-dicyanoethylene is below the above upper limit, it is easy to adjust the total content of (U-2) and (U-3) in the total amount of the above triad structure, and as a result, discoloration of a molded product using the copolymer after heating can be suppressed.

[0101] The amount of water contained in 1,1-dicyanoethylene can be measured by a method in accordance with JIS K0068:2001, for example.

[0102] [Resin composition]

[0103] The resin composition of the present invention contains the above copolymer and can be suitably used as a raw material for molded products, etc. As described above, the copolymer of the present invention can suppress coloration even after heating and is therefore particularly suitable as a material for films, etc.

[0104] The resin composition of the present invention is not particularly limited as long as it contains the above-mentioned copolymer, and may contain a synthetic resin in addition to the above-mentioned copolymer.

[0105] Other synthetic resins include polyethylene, polypropylene, copolymers of ethylene and one or more α-olefins having 3 to 20 carbon atoms (e.g., propylene, 1-butene, 1-pentene, 1-hexene, etc.), ethylene-propylene-diene copolymers (EPDM), ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers and other polyolefin resins, polyurethane resins, polyamide resins, polyester resins and polycarbonate resins.

[0106] Furthermore, the resin composition of the present invention may contain other components as necessary in addition to the copolymer of the present invention and the above-mentioned synthetic resin.

[0107] As other components, a solvent, a filler, a thickener, an anti-aging agent, a plasticizer, a flame retardant, a stabilizer, an antioxidant and the like may be contained.

[0108] From the viewpoint of suppressing coloration, the content of the copolymer in the resin composition of the present invention is preferably 0.1% by mass or more, more preferably 20% by mass or more, and even more preferably 50% by mass or more.

[0109] On the other hand, when the resin composition of the present invention contains optional components, namely the above-mentioned synthetic resin and other components, their total content is preferably 10% by mass or less, preferably 3% by mass or less, and preferably 0.001% by mass or more in the total amount of the resin composition.

[0110] <Method for producing resin composition>

[0111] The resin composition can be prepared by a method including a mixing step of mixing the copolymer of the present invention with the synthetic resin and other components as required. The method of mixing the components is not particularly limited and can be mixed by a known method.

[0112] [Molded products and films]

[0113] The molded product and film of the present invention use the copolymer or resin composition of the present invention. As the shape of the molded product, there is no restriction as long as it is a shape that can be manufactured using the copolymer or resin composition of the present invention, and various shapes such as films, pellets, sheets, plates, pipes, tubes, rods, and granules can be cited.

[0114] The method for producing the molded product is not particularly limited, and the molded product can be molded by various conventionally known molding methods, such as injection molding, blow molding, press molding, extrusion molding, and calendar molding.

[0115] The molded product of the present invention is preferably a film. As described above, the molded product using the copolymer of the present invention can suppress coloring even after heating, so by processing into a film, a film with better appearance can be obtained.

[0116] The film of the present invention can suppress coloration even after heating, so the difference in yellowness before heating and after heating at 140° C. for 1 hour under normal pressure is preferably 2.5% or less, more preferably 2.0% or less, further preferably 1.0% or less, and more preferably 0.9% or less.

[0117] The yellowness in the present invention is the yellowness measured in accordance with JIS Z8722:2009, and can be specifically measured by the method described in the Examples.

[0118] The film of the present invention preferably has low yellowness after heating. The yellowness after heating at 140° C. for 1 hour under normal pressure is preferably 2.5% or less, more preferably 1.5% or less, further preferably 1.0% or less, and further preferably 0.8% or less.

[0119] The thickness of the film of the present invention is not particularly limited, but is preferably 0.001 to 5.0 mm, more preferably 0.005 to 1.5 mm, further preferably 0.01 to 1.0 mm, further preferably 0.01 to 0.5 mm, further preferably 0.01 to 0.1 mm from the viewpoint of improving the transparency of the film.

[0120] The film of the present invention may be produced by any method known in the art, such as solution casting, melt extrusion, calendaring, compression molding, and injection molding.

[0121] [Conductive films, film capacitors]

[0122] In the conductive film of the present invention, a conductive layer is stacked on the above-mentioned film, and the film capacitor of the present invention includes the above-mentioned film or the above-mentioned conductive film.

[0123] The conductive film of the present invention uses the thin film of the present invention having an excellent relative dielectric constant, and therefore exhibits excellent performance as a film capacitor.

[0124] The conductive layer constituting the conductive film is not particularly limited, and is usually preferably a layer composed of a conductive metal such as aluminum, zinc, gold, platinum and copper, and is a metal foil or a metal coating (such as a vapor-deposited metal coating), and a combination of the two may be used. Among these, vapor-deposited metal coatings are preferred from the viewpoints of thinning the conductive layer and increasing the capacity relative to the volume, improving the adhesion with the dielectric, and reducing the unevenness of the thickness.

[0125] The vapor-deposited metal film may be formed into a multilayer structure by further forming a semiconductor aluminum oxide layer on an aluminum layer for the purpose of imparting moisture resistance, as described in Japanese Patent Application Laid-Open No. 2-250306, for example.

[0126] The thickness of the vapor-deposited metal film is not particularly limited, but is preferably 10 to 200 nm, more preferably 20 to 100 nm. When the thickness of the vapor-deposited metal film is within the above range, both the capacitance and the strength of the capacitor can be achieved, which is preferred.

[0127] When a deposited metal film is used as the conductive layer, the method for forming the film is not particularly limited, and for example, vacuum deposition, sputtering, ion plating, etc. may be used, and generally, vacuum deposition is preferred.

[0128] As the formation method of the conductive layer, for example, a batch method suitable for formed products, a semi-continuous method suitable for long strip products, and a continuous (air to air) method can be listed, and the semi-continuous method as the mainstream is preferred. The metal vapor deposition method of the semi-continuous method is a method as follows: metal vapor deposition is performed in a vacuum system, winding is performed, and then the vacuum system is restored to an atmospheric system, and the vapor-deposited film is taken out.

[0129] Example

[0130] Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples.

[0131] In addition, the water content in 1,1-dicyanoethylene in Examples, Comparative Examples, and Reference Examples was measured by a method in accordance with JIS K0068:2001.

[0132] <Example 1>

[0133] Into a 100-ml four-necked flask equipped with a stirring device, a Dimroth condenser and a thermometer, 2.0 g (0.026 mol, water content 390 ppm) of 1,1-dicyanoethylene synthesized by the method described in the above-mentioned document, 2.7 g (0.026 mol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 17 ml of toluene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 18 mg of 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) were added, and the mixture was heated and stirred at 40°C for 4 hours under a nitrogen flow to carry out free radical polymerization.

[0134] After the polymerization, the precipitated copolymer was filtered, washed with toluene and n-hexane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in that order, and then dried at 80°C overnight under reduced pressure. The yield of the product (copolymer powder) was 4.4 g, with a yield of 95%.

[0135] The obtained copolymer was subjected to spectrum measurement by NMR by the method described later. The results are shown in Table 1.

[0136] The obtained copolymer was dissolved in N,N-dimethylacetamide (manufactured by Tokyo Chemical Industry Co., Ltd.), applied by solution casting using an applicator (manufactured by Tester Industry Co., Ltd.) to a thickness of 50 μm, and vacuum dried at 40° C. and 1 kPa for 7 days to prepare a film before heating.

[0137] The yellowness of the obtained film was measured by the method described below. The results are shown in Table 1.

[0138] The relative dielectric constant of the obtained thin film was measured by the method described below. The results are shown in Table 1.

[0139] As shown in Table 1, the film of the present invention can suppress yellowness to a low level and has a high relative dielectric constant. Such a material with a high relative dielectric constant is suitable for use in film capacitors as described in Japanese Patent Application Laid-Open No. 2008-034189.

[0140] <Example 2, Comparative Examples 1 to 4>

[0141] A film was produced in the same manner as in Example 1 except that the water concentration in 1,1-dicyanoethylene, the polymerization temperature, and the ratio of the charged amounts were changed as described in Tables 1 and 2.

[0142] The spectrum of the obtained copolymer was measured by NMR in the same manner as in Example 1, and the yellowness of the obtained film was measured.

[0143] <Example 3>

[0144] Into a 300 ml autoclave equipped with a stirrer and a thermometer, 2.0 g (0.026 mol, water content 390 ppm) of 1,1-dicyanoethylene synthesized by the method described in the above-mentioned document, 3.6 g of isobutylene (0.064 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), 6.7 ml of ethyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 18 mg of 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) were added, and heated and stirred at 40°C for 6 hours under a nitrogen flow to carry out free radical polymerization.

[0145] After the polymerization, the precipitated copolymer was filtered, washed with ethyl acetate and n-hexane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in that order, and then dried at 80° C. under reduced pressure overnight to obtain a product (copolymer powder).

[0146] The obtained copolymer was subjected to NMR spectrum measurement by the method described later, and a thin film was prepared and the yellowness of the obtained copolymer was measured in the same manner as in Example 1. The results are shown in Table 1.

[0147] <Example 4>

[0148] Into a 300 ml autoclave equipped with a stirrer and a thermometer were added 2.0 g (0.026 mol, water content 390 ppm) of 1,1-dicyanoethylene synthesized by the method described in the aforementioned document, 2.7 g of propylene (0.064 mol, manufactured by Takachiho Chemical Industry Co., Ltd.), 8.9 ml of ethyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 18 mg of 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and the mixture was heated and stirred at 40°C for 6 hours under a nitrogen flow to carry out free radical polymerization.

[0149] <Examples 5 to 8, Comparative Examples 5 to 8>

[0150] A thin film was produced in the same manner as in Example 3 except that the water concentration in 1,1-dicyanoethylene, the polymerization temperature, and the ratio of the charged amounts were changed as shown in Tables 1 and 2.

[0151] The spectrum of the obtained copolymer was measured by NMR in the same manner as in Example 3, and the yellowness of the obtained film was measured.

[0152] <Example 9, Comparative Examples 9 and 10>

[0153] A thin film was produced in the same manner as in Example 4 except that the water concentration in 1,1-dicyanoethylene, the polymerization temperature, and the ratio of the charged amounts were changed as shown in Tables 1 and 2.

[0154] The spectrum of the obtained copolymer was measured by NMR in the same manner as in Example 4, and the yellowness of the obtained film was measured.

[0155] After the polymerization, the precipitated copolymer was filtered, washed with ethyl acetate and n-hexane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in that order, and then dried at 80° C. under reduced pressure overnight to obtain a product (copolymer powder).

[0156] The obtained copolymer was subjected to NMR spectrum measurement by the method described later, and a thin film was prepared using the obtained copolymer in the same manner as in Example 1, and the yellowness was measured.

[0157] <Reference Examples 1 to 5>

[0158] Referring to US Patent Application Publication No. 2615868, the water concentration in 1,1-dicyanoethylene, the polymerization temperature and the ratio of the input amount were as shown in Table 3 to produce a copolymer, and a film was prepared in the same manner as in Example 1.

[0159] The spectrum of the obtained copolymer was measured by NMR in the same manner as in Example 1, and the yellowness of the obtained film was measured.

[0160] <Measurement method>

[0161] (1) Spectral measurement of copolymers by NMR

[0162] The product (copolymer powder) was measured using a nuclear magnetic resonance spectrometer (NMR) under the following conditions: 1 H-NMR and 13 C-NMR spectrum. Using the measurement results, the ratio of each triad structure was determined according to the method described in Non-Patent Document 1. The results are shown in Tables 1 to 3.

[0163] [ 1 H-NMR measurement conditions]

[0164] Device: JNM-ECX400 manufactured by JEOL Ltd.

[0165] Determination solvent: deuterated dimethyl sulfoxide

[0166] Measuring temperature: 65℃

[0167] Chemical shift value standard: tetramethylsilane

[0168] [ 13 C-NMR measurement conditions]

[0169] Device: JNM-ECX400 manufactured by JEOL Ltd.

[0170] Determination solvent: deuterated dimethyl sulfoxide

[0171] Measuring temperature: 65℃

[0172] Determination method: Proton decoupling method

[0173] Pulse width: 45 degrees

[0174] Pulse repetition time: 10 seconds

[0175] Chemical shift value standard: tetramethylsilane

[0176] (2) Determination of yellowness of film

[0177] The films obtained in Examples, Comparative Examples and Reference Examples were heated in a clean oven DE-41 (manufactured by Yamato Scientific Co., Ltd.) at 140° C. under normal pressure for 1 hour.

[0178] The yellowness of the film before and after heating was measured using a haze meter SH7000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.) in accordance with JIS Z8722:2009.

[0179] In addition, about yellowness, the value of 3 places of each film was measured, and the average value was adopted as yellowness. The results are shown in Tables 1-3.

[0180] (3) Determination of relative dielectric constant of thin films

[0181] After the thin films obtained in the examples, comparative examples and reference examples were humidified at 26°C and 60% RH, Au-Pd alloy with a diameter of 30 mm was vapor-deposited on the surface of the film until the surface was conductive, and vapor deposition was also performed on the opposite side to form a conductive layer to make a thin film capacitor sample.

[0182] The electrostatic capacitance (C) of the sample was measured using an LCR meter (manufactured by Keysight). The capacitance, electrode area (S), and film thickness (d) were used to calculate the value of C = ε × ε. 0 ×S / d(ε 0 The relative dielectric constant was calculated using the dielectric constant of vacuum. The results are shown in Tables 1 to 3.

[0183] [Table 1]

[0184]

[0185] [Table 2]

[0186]

[0187] [Table 3]

[0188]

[0189] The results in Tables 1 to 3 show that the copolymer of the present invention can suppress coloring even after heating and can therefore be suitably used for molded products such as films.

[0190] As described above, Reference Examples 1 to 5 were tested according to the description of U.S. Patent Application Publication No. 2615868, but the content of (U-2) and (U-3) in the total amount of the above four triad structures in the copolymer obtained by the method described in the above document was not less than 5.5 mol %. Therefore, the films of Reference Examples 1 to 5 produced using the copolymers were colored after heating.

Claims

1. A copolymer comprising a structural unit (A) derived from 1,1-dicyanoethylene and a structural unit (B) derived from a compound represented by the following general formula (I), CH2=CR 1 R 2 (I) It is characterized in that The copolymer contains the following four triad structures (U-1) to (U-4) composed of the structural unit (A) and the structural unit (B), (A)-(A)-(A) … (U-1) (A)-(A)-(B) … (U-2) (B)-(A)-(A) … (U-3) (B)-(A)-(B) … (U-4) The content of (U-2) and (U-3) in the total amount of the four triad structures is 5.5 mol % or less, In the general formula (I), R 1 is one or more selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group and a halogen atom, R 2 is at least one selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a halogen atom and a halogenated alkyl group.

2. The copolymer according to claim 1, wherein The content of (U-1) in the total amount of the four triad structures is 1.8 mol % or less.

3. The copolymer according to claim 1 or 2, wherein The content of the structural unit (A) in the total amount of the copolymer is 30 to 55 mol %.

4. The copolymer according to any one of claims 1 to 3, wherein The compound represented by the general formula (I) is at least one selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, isobutylene, 1-hexene, propylene and ethylene.

5. A method for producing a copolymer, which is a method for producing the copolymer according to any one of claims 1 to 4, wherein: The polymerization temperature is 45° C. or lower, the amount of the compound represented by the general formula (I) charged is 0.80 to 3.5 equivalents relative to the amount of 1,1-dicyanoethylene charged, and the production is carried out in the presence of a radical polymerization initiator. 6 . A resin composition comprising the copolymer according to claim 1 .

7. A molded product using the copolymer according to any one of claims 1 to 4 or the resin composition according to claim 6.

8. A film comprising the copolymer according to any one of claims 1 to 4 or the resin composition according to claim 6, wherein: The difference between the yellowness before heating and the yellowness after heating at 140° C. under normal pressure for 1 hour was 2.5% or less.

9. A conductive film, wherein: A conductive layer is laminated on the film according to claim 8. 10 . A thin film capacitor comprising the thin film according to claim 8 or the conductive thin film according to claim 9 .

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