Polyimide film and wearable device

Abstract

To provide a material suitable as a sensor device and a wearable device.SOLUTION: There is provided a polyimide film comprising a polyimide having a structural unit derived from diamine and a structural unit derived from aromatic acid dianhydride, which contains, as a structural unit derived from diamine, at least a structural unit derived from a silicon-containing diamine represented by formula (1) and a structural unit derived from an aromatic diamine, wherein the ratio of the structural unit derived from a silicon-containing diamine to the total amount of structural units derived from diamine is 45 wt.% or more. (In the formula, R1 and R2 are each independently a divalent aliphatic hydrocarbon group having a carbon number of 3 to 20, R3, R4, R5 and R6 are each independently a monovalent aliphatic hydrocarbon group having a carbon number of 1 to 3 or an aromatic group, m is an integer of 1 or more.)SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polyimide film. The polyimide film of the present invention is useful as a material suitable for wearing in applications of sensor devices or wearable devices. [Background technology]

[0002] A wearable device is a device such as a sensor that can be worn on various parts of the human body, such as the wrist, arm, ankle, etc. The shape of the device can be, for example, a wristband type, a watch type, a clip type, a glasses type, a ring type, or a speaker type. These wearable devices are attached to the human body directly or through clothing, so they need to be comfortable to use. From this perspective, high elasticity and high moisture permeability are considered to be required.

[0003] In general, wearable devices are made of synthetic polymers rather than natural materials. Synthetic polymers exhibit various characteristics depending on the monomers, initiators, modifiers, etc. that compose them. When used, there is concern that the synthetic polymer itself, or additives or impurities used in combination with the synthetic polymer, may be toxic to human tissues such as the skin or cause allergic reactions. For this reason, wearable devices require materials that are not toxic or do not cause allergic reactions, i.e., are biologically safe.

[0004] There are various synthetic polymers used in wearable devices, but polyimide is expected to be a promising candidate from the viewpoints of heat resistance, chemical stability, mechanical strength, and moisture permeability. Patent Documents 1 and 2 disclose polyimide films having specific aromatic diamines and acid dianhydrides as monomers. Patent Document 3 discloses a photosensitive polyimide film containing a polyimide resin using polyetheramine as a diamine monomer.

[0005] Among the polyimide resins, polyimides having a siloxane skeleton in the main chain (hereinafter also referred to as "silicone-modified polyimides" or "siloxane-containing polyimides") have attracted attention from the viewpoints of elasticity, hydrophobicity, and mechanical properties, and those having a specific skeleton have been disclosed. Patent Document 4 discloses a laminate of a urethane resin having a urethane bond and a siloxane bond, and a silicone-modified polyimide resin. Patent Document 5 discloses a silicone rubber-silicone-modified polyimide resin laminate in which a silicone-modified polyimide resin layer is provided on a silicone rubber surface. Patent Document 6 discloses a silicone-modified polyimide resin as a material for forming a biological contact layer.

[0006] In recent years, various infectious diseases have become prevalent around the world, some of which can have serious effects on the human body, and therefore it is recommended to remove bacteria from the human body. Depending on the degree of bacteria removal, there are methods such as sterilization, disinfection, sterilization, etc., and sterilization has the highest rate of bacteria removal. One of the methods of sterilization is gamma radiation.

[0007] Gamma ray irradiation is known as a method for sterilizing medical devices. Gamma rays are not only highly germicidal, but also have a high penetrating power, so they have the advantage of placing fewer restrictions on the product form to be sterilized. For this reason, the materials that make up wearable devices are required to be resistant to deterioration by gamma ray irradiation. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2022 / 259841 [Patent Document 2] Special Publication No. 2022-510308 [Patent Document 3] JP 2020-76092 A [Patent Document 4] JP 2022-156876 A [Patent Document 5] JP 2019-171763 A [Patent Document 6] JP 2018-11931 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, none of the polyimides and silicone-modified polyimides disclosed in the above patent documents have high levels of elasticity, moisture permeability, biological safety, and gamma-ray resistance, which are important factors for application to wearable devices. In view of the above circumstances, an object of the present invention is to provide a material that has high levels of stretchability, moisture permeability, biological safety, and gamma-ray resistance, and is suitable for use in wearable devices. [Means for solving the problem]

[0010] As a result of extensive investigations, the present inventors have found that a polyimide film using a silicone-modified polyimide having a specific structure can satisfy the above-mentioned properties, and have thus completed the present invention.

[0011] That is, the present invention relates to a polyimide film comprising a polyimide having a structural unit derived from a diamine and a structural unit derived from an aromatic acid dianhydride, characterized in that the polyimide contains 45 weight % or more of the structural unit derived from a silicon-containing diamine represented by formula (1) based on the entire polyimide structure.

[0012] [ka] (In the formula, R 1 and R 2 are each independently a divalent aliphatic hydrocarbon group having 3 to 20 carbon atoms, R 3 , R 4 , R 5 and R 6 are each independently a monovalent aliphatic hydrocarbon group or aromatic group having 1 to 3 carbon atoms, and m is an integer of 1 or greater. Hereinafter, the polyimide may be referred to as a siloxane-containing polyimide.

[0013] Furthermore, in the safety tests stipulated in the United States Pharmacopeia, the polyimide film of the present invention was evaluated as grade 0 (None) in a cytotoxicity test, no test animals died in a systemic toxicity test, and no test animals developed abnormalities in an intradermal toxicity test.

[0014] The polyimide film of the present invention preferably contains, as the structural unit derived from the aromatic acid dianhydride, at least one structural unit derived from selected from the group consisting of 1,2,4,5-benzenetetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, and 3,3',4,4'-biphenyltetracarboxylic dianhydride.

[0015] The structural unit derived from the diamine preferably comprises a structural unit derived from a silicon-containing diamine represented by formula (1) and a structural unit derived from an aromatic diamine. The structural unit derived from the aromatic diamine preferably includes one or more selected from the group consisting of 2,2-bis(4-aminophenoxyphenyl)propane and 9,9-bis(4-aminophenyl)fluorene, and m in the structural unit formula (1) derived from the silicon-containing diamine is preferably 1 or 2.

[0016] Moreover, a laminate device that can be worn on the human body can be produced by laminating a conductive layer on one or both sides of the polyimide film of the present invention and laminating a semiconductor component on the conductive layer. An example of this is shown in the conceptual diagram of Figure 1. The obtained laminate device can be preferably used as a sensor device.

[0017] The laminate device or sensor device of the present invention can be used as a wearable device by being attached so as to come into contact with human skin directly or indirectly via clothing. Effect of the Invention

[0018] The polyimide film of the present invention is excellent in elasticity, moisture permeability, biological safety, and gamma-ray resistance. Therefore, a laminate device or a sensor device produced using the polyimide film of the present invention is excellent in safety to the human body, and can be provided as a comfortable and safe wearable device. [Brief description of the drawings]

[0019] [Figure 1] Conceptual diagram of a stacked device DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The polyimide film of the present invention is a polyimide film comprising a polyimide having a structural unit derived from a diamine and a structural unit derived from an aromatic acid dianhydride, and the polyimide is a siloxane-containing polyimide containing 45% by weight or more of the structural unit derived from a silicon-containing diamine represented by formula (1) based on the entire polyimide structure.

[0021] [ka] (In the formula, R 1 and R 2 are each independently a divalent aliphatic hydrocarbon group having 3 to 20 carbon atoms, R 3 , R 4 , R 5 and R 6 are each independently a monovalent aliphatic hydrocarbon group or aromatic group having 1 to 3 carbon atoms, and m is an integer of 1 or greater.

[0022] In the silicon-containing diamine represented by the above formula (1), m, which represents the number of repeating units of the siloxane unit in the main chain, is preferably 1 or 2, and more preferably m = 1. The molecular weight of the silicon-containing diamine is a number average molecular weight of 500 or less, more preferably a number average molecular weight of 400 or less, and even more preferably a number average molecular weight of 300 or less. The number average molecular weight of the silicon-containing diamine can be measured by liquid chromatography or gel permeation chromatography (GPC).

[0023] In addition, in the above formula (1), R 1 and R 2 are each independently a divalent aliphatic hydrocarbon group having 3 to 20 carbon atoms. From the viewpoint of gamma ray resistance, they are preferably alkylene groups having 1 to 6 carbon atoms, in particular a methylene group, an ethylene group or a propylene group. Also, R 3 , R 4 , R 5 and R 6 are each independently a monovalent aliphatic hydrocarbon group having 1 to 3 carbon atoms, preferably a methyl group from the viewpoint of gamma-ray resistance. In formula (1), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be different from each other or may be the same.

[0024] In the safety tests specified in the United States Pharmacopeia, the polyimide film of the present invention was evaluated as grade 0 (None) in a cytotoxicity test, no test animals died in a systemic toxicity test, and no test animals developed abnormalities in an intradermal toxicity test. Furthermore, in a gamma ray resistance test, the rate of change in tensile modulus after two months of gamma ray irradiation is 20% or less, and the rate of change in glass transition temperature after two months of gamma ray irradiation is 10% or less.

[0025] In the siloxane-containing polyimide of the present invention, the structural unit derived from the silicon-containing diamine represented by the above formula (1) accounts for 45% by weight or more, preferably 55% by weight or more, more preferably 65% ​​by weight or more of the total polymerization units constituting the polyimide structure. The ratio of the structural unit derived from the silicon-containing diamine represented by the above formula (1) is the ratio of the silicon-containing diamine unit to the polymerization units constituting the polyimide, and usually corresponds to the weight ratio (weight %) of the silicon-containing diamine to the total weight of the aromatic dianhydride and diamine used in the polyimide polymerization reaction. In the present invention, this ratio (weight %) is called the siloxane component ratio.

[0026] If the siloxane content of the siloxane-containing polyimide is less than 45% by weight, the tensile elongation (i.e., stretchability) and moisture permeability will decrease, causing problems in terms of comfort when used as a wearable device.

[0027] On the other hand, from the viewpoint of heat resistance and prevention of generation of cyclic siloxane, the upper limit of the siloxane content relative to the total polymerization units constituting the polyimide structure is preferably 90% by weight. The structural unit derived from the silicon-containing diamine may be the sum of structural units derived from one or a combination of a plurality of the silicon-containing diamines.

[0028] Cyclic siloxanes, when attached to, for example, silicon wafers, can alter the characteristics of semiconductors, raising concerns about reduced product yields. However, the polyimide film of the present invention, in which generation of cyclic siloxanes is suppressed, can also be applied to semiconductor production lines.

[0029] The structural units and their ratios of the siloxane-containing polyimide of the present invention are determined by the types and the ratios of the diamine and dianhydride used as raw materials. Therefore, the structural units constituting the polyimide will be explained in terms of the diamine and dianhydride used. The ratios of the structural units derived from the diamine and the structural units derived from the dianhydride constituting the polyimide are the same as the ratios of the diamine and the dianhydride used in the production of the polyimide.

[0030] In the siloxane-containing polyimide of the present invention, in addition to the silicon-containing diamine represented by the above formula (1), one or more aromatic diamines (hereinafter simply referred to as "aromatic diamines") selected from 2,2-bis(4-aminophenoxyphenyl)propane (BAPP) and 9,9-bis(4-aminophenyl)fluorene (BAFL), which are silicon-free aromatic diamines, can be used as diamines. The combined use of BAPP and / or BAFL is preferred because it improves the heat resistance and gamma-ray resistance of the polyimide film.

[0031] That is, in one preferred embodiment of the present invention, the diamine-derived structural unit constituting the siloxane-containing polyimide comprises a combination of a silicon-containing diamine represented by formula (1) and the aromatic diamine.

[0032] The ratio of the structural units derived from the aromatic diamine (BAPP and / or BAFL) constituting the polyimide to the total structural units derived from the diamine is in the range of 0 to 95 mol%. From the viewpoint of gamma-ray resistance, the preferred upper limit of the structural units derived from the aromatic diamine is 80 mol%, more preferably 50 mol%, and even more preferably 35 mol%. On the other hand, from the viewpoint of heat resistance and prevention of generation of cyclic siloxane, the preferred lower limit of the structural units derived from the aromatic diamine is 10 mol%, more preferably 15 mol%. The ratio (mol%) of the structural units derived from the aromatic diamine to the total structural units derived from the diamine usually corresponds to the amount of the aromatic diamine used with respect to the total amount of the diamine to be subjected to the polyimide polymerization reaction.

[0033] In addition to the silicon-containing diamine represented by the formula (1) and the aromatic diamine (BAPP and / or BAFL), another diamine (hereinafter referred to as a "third diamine") may be used. As the third diamine, a diamine having one or more aromatic rings is suitable from the viewpoint of heat resistance and gamma-ray resistance.

[0034] Examples of the third diamine include 2,2'-dimethyl-4,4'-diaminobiphenyl (also known as 2,2'-dimethyl-benzidine), 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,6-dimethyl-m-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, 2,4-diaminomesitylene, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2, 6-diethylaniline, 2,4-toluenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone,

[0035] 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, benzidine, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 4,4'-diamino-p-terphenyl, 3,3'-diamino-p-terphenyl, bis(p-β-amino-t-butylphenyl)ether, bis(p-β-methyl-δ-aminopentyl)benzene, p-bis(2-methyl-4-aminopentyl)benzene, p-bis(1,1-dimethyl-5-aminopentyl)benzene,

[0036] Examples of the diaminophenyl ether include 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis(β-amino-t-butyl)toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, and 5-amino-2-(4-aminophenyl)benzimidazole. Moreover, these third diamines may be used alone or in combination of two or more kinds.

[0037] Preferably, the structural units derived from the third diamine constituting the siloxane-containing polyimide account for 20 mol % or less, and more preferably 10 mol % or less, of the total structural units derived from the diamine.

[0038] The siloxane-containing polyimide of the present invention contains at least a structural unit derived from an acid dianhydride having an aromatic structure in the skeleton (hereinafter referred to as "aromatic acid dianhydride") as a structural unit derived from an acid dianhydride. The use of an aromatic acid dianhydride improves the properties of the polyimide film, such as heat resistance. It is preferable that the polyimide contains a structural unit derived from one or more selected from 1,2,4,5-benzenetetracarboxylic dianhydride (PMDA, also referred to as "pyromellitic dianhydride"), 3,3',4,4'-diphenylethertetracarboxylic dianhydride (ODPA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA). Hereinafter, PMDA, ODPA, DSDA and BPDA are collectively referred to as "preferred aromatic acid dianhydride".

[0039] When producing the polyimide of the present invention, it is preferable to use one or more selected from the above-mentioned preferable aromatic dianhydrides. By using these preferable aromatic dianhydrides as the acid dianhydride, the properties required for the polyimide film, such as heat resistance, are further improved.

[0040] The ratio of the structural units derived from the aromatic dianhydride constituting the siloxane-containing polyimide of the present invention to the total structural units derived from the dianhydride is preferably 50 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more. All of the structural units derived from the aromatic dianhydride may be occupied by structural units derived from one of the preferred aromatic dianhydrides, i.e., PMDA, ODPA, DSDA, and BPDA, or a combination of two or more of these. The ratio (mol %) of the structural units derived from a preferred aromatic acid dianhydride to all structural units derived from acid dianhydrides usually corresponds to the amount of the preferred aromatic acid dianhydride used relative to the total amount of acid dianhydrides to be subjected to the polyimide polymerization reaction.

[0041] In addition to the preferred aromatic dianhydrides, other dianhydrides (hereinafter referred to as "second dianhydrides") may be used. As the second dianhydride, from the viewpoints of heat resistance and gamma-ray resistance, dianhydrides other than the preferred aromatic dianhydrides having one or more aromatic rings, that is, dianhydrides of aromatic tetracarboxylic acids other than PMDA, ODPA, DSDA, or BPDA, are suitable.

[0042] Examples of the aromatic tetracarboxylic acid dianhydride as the second acid dianhydride include 4,4'-(2,2'-hexafluoroisopropylidene)diphthalic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, naphthalene-1,2,6,7-tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride,

[0043] Naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, naphthalene-1,2,6,7-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 1,4,5,8-tetrachloronaphthalene-2,3,6,7-tetracarboxylic dianhydride,

[0044] 2,2',3,3'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3'',4,4''-p-terphenyltetracarboxylic dianhydride, 2,2'',3,3''-p-terphenyltetracarboxylic dianhydride, 2,3,3'',4''-p-terphenyltetracarboxylic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-propane dianhydride 1,1-bis(2,3-dicarboxyphenyl)propane dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride,

[0045] Perylene-2,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, perylene-4,5,10,11-tetracarboxylic dianhydride, perylene-5,6,11,12-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,6,7-tetracarboxylic dianhydride, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyridine azine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, (trifluoromethyl)pyromellitic dianhydride, di(trifluoromethyl)pyromellitic dianhydride, di(heptafluoropropyl)pyromellitic dianhydride, pentafluoroethylpyromellitic dianhydride, bis{3,5-di(trifluoromethyl)phenoxy}pyromellitic dianhydride,

[0046] 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-tetracarboxybiphenyl dianhydride, 2,2',5,5'-tetrakis(trifluoromethyl)-3,3',4,4'-tetracarboxybiphenyl dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-tetracarboxydiphenyl ether dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-tetracarboxybenzophenone dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}benzene dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}, trifluoromethylbenzene dianhydride, bis(dicarboxyphenoxy)trifluoromethylbenzene dianhydride,

[0047] Examples of the dianhydride include bis(dicarboxyphenoxy)bis(trifluoromethyl)benzene dianhydride, bis(dicarboxyphenoxy)tetrakis(trifluoromethyl)benzene dianhydride, 2,2-bis{4-(3,4-dicarboxyphenoxy)phenyl}hexafluoropropane dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}biphenyl dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}bis(trifluoromethyl)biphenyl dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}diphenyl ether dianhydride, and bis(dicarboxyphenoxy)bis(trifluoromethyl)biphenyl dianhydride. These may be used alone or in combination of two or more.

[0048] The structural units derived from the second acid dianhydride constituting the siloxane-containing polyimide of the present invention preferably account for 20 mol % or less, and more preferably 10 mol % or less, of the total structural units derived from the acid dianhydride.

[0049] In the polymerization of the siloxane-containing polyimide of the present invention, for example, a diamine including the silicon-containing diamine and an acid dianhydride including an aromatic acid dianhydride are used in a molar ratio of 0.9 to 1.1, and a precursor of the polyimide of the present invention (hereinafter also referred to as "the polyimide precursor") is produced by a method of polymerization in an organic polar solvent. Specifically, the polyimide precursor is obtained by dissolving a diamine in an aprotic amide solvent such as N,N-dimethylacetamide or N-methyl-2-pyrrolidone under a nitrogen stream, adding an acid dianhydride, and reacting at room temperature for about 3 to 20 hours. To speed up the reaction, the mixture may be heated at a temperature of 40°C to 80°C for 15 minutes to 5 hours.

[0050] Other organic polar solvents used in the polymerization include dimethylformamide, 2-butanone, diglyme, xylene, γ-butyrolactone, etc., and these can be used alone or in combination of two or more. In some cases, xylene, hexane, etc. can be added to increase solubility.

[0051] The polyimide precursor has a structure in which the diamine and the acid dianhydride do not completely form imide bonds, but remain partially as amide bonds. The molecular ends of the polyimide precursor may be blocked with an aromatic monoamine or aromatic monocarboxylic acid.

[0052] The siloxane-containing polyimide of the present invention is obtained by imidizing the amide bond of the polyimide precursor. The imidization can be performed by a thermal imidization method or a chemical imidization method. The thermal imidization is performed by heat-treating a solution of the polyimide precursor at a temperature of about 180°C to 360°C for about 10 minutes to 20 hours. The heat treatment temperature can be changed between 180°C and 360°C depending on the required mechanical properties.

[0053] Thermal imidization can be completed in a relatively short time by selecting the right combination of acid dianhydride, diamine, and solvent. It is also possible to complete the imidization reaction in less than 60 minutes, including preheating to remove the solvent. In chemical imidization, a dehydrating agent and a catalyst are added to a polyimide precursor solution, and a chemical dehydration-imidization reaction is carried out at 30° C. to 60° C. A typical example of the dehydrating agent is acetic anhydride, and a typical example of the reaction catalyst is pyridine.

[0054] The polyimide film of the present invention can be obtained by applying the above-mentioned polyimide precursor or polyimide solution onto any supporting substrate such as glass, metal, or resin, and then heat treating it. When using a solution of a polyimide precursor, the solution is heated at a temperature of 150°C or less for 2 to 60 minutes to remove the solvent, and then thermally imidized by heat treatment at a temperature of about 180°C to 360°C for about 10 minutes to 20 hours. When a polyimide solution is used, the solution can be heated at a temperature of 150° C. or less for 2 to 60 minutes to remove the solvent.

[0055] The preferred degree of polymerization of the polyimide precursor is 1,000 to 100,000 cP, preferably 3,000 to 10,000 cP, as measured by an E-type viscometer for the polyimide precursor solution. The molecular weight of the polyimide precursor can be determined by a GPC method. The preferred molecular weight range of the polyimide precursor (polystyrene equivalent) is preferably 15,000 to 250,000 in number average molecular weight and 30,000 to 800,000 in weight average molecular weight, but these are guidelines and do not mean that all polyimide precursors outside these ranges cannot be used. The preferred degree of polymerization (molecular weight) of the siloxane-containing polyimide of the present invention is also in the same range as the preferred degree of polymerization (molecular weight) of the polyimide precursor described above.

[0056] The polyimide film of the present invention may contain other optional components in an amount of up to 10% by weight depending on the desired physical properties. Examples of other optional components include polyimides other than the polyimide of the present invention, organic fillers, and inorganic fillers.

[0057] Gamma-ray resistance testing is a test to detect changes in physical properties before and after a film is irradiated with sterilizing levels of gamma rays for a long period of time. For example, after irradiating a polyimide film with 50 kGy of gamma rays for two months, the physical properties of the film are compared before and after irradiation to test the gamma-ray resistance of the polyimide film.

[0058] In the present invention, the rate of change in the tensile modulus of the polyimide film after gamma ray irradiation is determined as the increase or decrease in the tensile modulus after gamma ray irradiation, and is preferably 20% or less, more preferably 10% or less. The rate of change in tensile modulus of elasticity can be calculated by the following formula, where A is the tensile modulus of elasticity of the film irradiated with gamma rays and B is the tensile modulus of elasticity of the film not irradiated with gamma rays. Change in tensile modulus = |AB| / B (%)

[0059] In the present invention, the rate of change in the glass transition temperature (Tg) of the polyimide film after gamma ray irradiation is determined as the increase or decrease in the glass transition temperature after gamma ray irradiation, and is preferably 10% or less, more preferably 6% or less. The rate of change in glass transition temperature can be calculated by the following formula, where a is the glass transition temperature of the film irradiated with gamma rays and b is the glass transition temperature of the film not irradiated with gamma rays. Glass transition temperature change rate = |ab| / b (%)

[0060] A laminate device can be produced by laminating a conductive layer on one or both sides of the polyimide film of the present invention and laminating a semiconductor component on the conductive layer. Fig. 1 is a conceptual diagram of an example of a laminate device in which a conductive material and a semiconductor component are laminated on a stretchable substrate using the polyimide film of the present invention. Examples of the semiconductor parts include LED light-emitting materials, antennas, and various sensors. Examples of the laminate devices produced using the polyimide film of the present invention include sensor devices.

[0061] The United States Pharmacopeia prescribes cytotoxicity tests, systemic toxicity tests, and intradermal toxicity tests for safety tests on the human body.

[0062] The cytotoxicity test refers to the Elution Cytotoxicity Study defined in the United States Pharmacopeia (USP). In this test, the grade of the polyimide film of the present invention being 0 means that the intracytoplasmic particles are present separately and there is no cell lysis, which means that the polyimide film has no cytotoxicity.

[0063] The systemic toxicity test refers to the Systemic Toxicity Study defined in the United States Pharmacopeia (USP). In this test, if no test animals die from the polyimide film of the present invention, it means that the polyimide film has no systemic toxicity.

[0064] The intracutaneous toxicity test refers to the intracutaneous study defined in the United States Pharmacopeia (USP). In this test, if no test animal develops abnormality in response to the polyimide film of the present invention, it means that the polyimide film has no intracutaneous toxicity.

[0065] The polyimide film made of the siloxane-containing polyimide of the present invention has a grade of 0 in the cytotoxicity test in the safety tests specified by the United States Pharmacopeia, no test animals died in the systemic toxicity test, and no test animals developed abnormalities in the intradermal toxicity test. In other words, the polyimide film of the present invention is highly compatible with the human body.

[0066] The polyimide film made of the siloxane-containing polyimide of the present invention is significantly superior in stretchability, moisture permeability, biological safety, and gamma-ray resistance to films made of conventional polyimides or films made of silicone-modified polyimides. The polyimide film of the present invention is particularly resistant to deterioration caused by gamma-ray irradiation.

[0067] Since the polyimide film of the present invention has the above-mentioned properties, it can be worn and used so as to come into contact with human skin directly or indirectly through clothing, and is particularly suitable for use as a wearable device. Specifically, it can be suitably applied to various resin materials constituting wearable devices, such as substrates, adhesives, and solder resists for wearable devices.

[0068] Wearable devices using the polyimide film of the present invention can be used particularly as clothing. Here, clothing includes not only ordinary clothing, i.e., clothes, but also items worn on the body such as nightwear, underwear, undergarments, bathrobes, gowns, corsets, cooking apron, swimsuits, sportswear, and bedding (sheets, pillowcases), as well as items worn on a part of the body such as neck wraps, masks, socks, gloves, hats, pouches, and supports.

[0069] In addition, since the polyimide film of the present invention has heat resistance and suppresses the generation of cyclic siloxane, it can be used as a material for manufacturing semiconductor parts.Specifically, it can be suitably applied to the manufacturing process of semiconductor parts, which includes a fixing process of attaching and fixing a silicon wafer to a substrate having a tacky adhesive layer on one side of the polyimide film of the present invention, a processing process of the silicon wafer, a dicing process of cutting the silicon wafer attached to the substrate to obtain semiconductor chips, and a pick-up process of peeling the substrate from the semiconductor chips.

[0070] That is, one aspect of the present invention is a method for producing a semiconductor component, comprising: a fixing step of attaching and fixing a silicon wafer to a substrate having a tacky adhesive layer provided on one side of the polyimide film of the present invention; a silicon wafer processing step; a dicing step of cutting the silicon wafer with the substrate attached thereto to obtain semiconductor chips; and a pick-up step of peeling the substrate from the semiconductor chips.

[0071] Another aspect of the present invention is a film for fixing a silicon wafer, which comprises a pressure-sensitive adhesive layer for fixing a silicon wafer on one side of the polyimide film of the present invention, and is used in the manufacturing process of semiconductor parts. EXAMPLES

[0072] The present invention will be specifically described below based on examples and comparative examples, but the present invention is not limited to these examples.

[0073] Details of materials used in the examples and comparative examples are shown below. (acid dianhydride) BPDA: 3,3´,4,4´-biphenyltetracarboxylic dianhydride ODPA: 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride BTDA: 1,2,4,5-benzenetetracarboxylic dianhydride DSDA: 3,3´,4,4´-diphenylsulfonetetracarboxylic dianhydride

[0074] (Diamine) PCX-A (silicon-containing diamine A): Diaminosiloxane having a number average molecular weight of 740 represented by the following formula (2) (where m is a mixture in the range of 1 to 20) PCX-B (silicon-containing diamine B): Diaminosiloxane having a number average molecular weight of 1000 represented by the following formula (2) (where m is a mixture within the range of 1 to 20) PCX-C (silicon-containing diamine C): Diaminosiloxane having a number average molecular weight of 1240 represented by the following formula (2) (where m is a mixture in the range of 1 to 20) PCX-D (silicon-containing diamine D): Diaminosiloxane having a number average molecular weight of 2000 represented by the following formula (2) (where m is a mixture in the range of 1 to 20) BY16-871 (silicon-containing diamine E): Diaminosiloxane having a molecular weight of 232.5 and represented by the following formula (2) (where m=1); manufactured by Dow Toray Co., Ltd.

[0075] [ka]

[0076] ·BAPP (aromatic diamine): 2,2-bis(4-aminophenoxyphenyl)propane ·BAFL (aromatic diamine): 9,9-bis(4-aminophenyl)fluorene

[0077] Example 1 A 1000 ml separable flask was charged with acid dianhydride BPDA (0.12 mol), 200 g of N-methyl-2-pyrrolidone (NMP), and 200 g of xylene, and mixed at room temperature. Next, silicon-containing diamine A (0.099 mol) was added dropwise using a dropping funnel, followed by the addition of aromatic diamine BAPP (0.021 mol), and the mixture was stirred at room temperature for 2 hours to obtain a siloxane-containing polyimide precursor solution. This polyimide precursor solution was heated to 190°C and stirred for 20 hours to obtain a polyimide solution having a weight average molecular weight (Mw) of 70,000. This polyimide solution was applied onto a release film and dried to form a film, and the release film was peeled off to obtain a polyimide film.

[0078] (Examples 2 to 11) A siloxane-containing polyimide precursor solution was prepared in the same manner as in Example 1, except that the acid dianhydride and diamine were changed to the compositions shown in Table 1, and a polyimide film was obtained.

[0079] (Comparative Examples 1 to 5) A polyimide precursor solution was prepared in the same manner as in Example 1, except that the combination of the acid dianhydride and the diamine was changed to the composition shown in Table 2, and a polyimide film was obtained.

[0080] The abbreviations for the acid dianhydrides and diamines in Tables 1 and 2 have the same meanings as above. The siloxane component ratio is a value calculated by the following formula. Siloxane component ratio=(weight of siloxane-skeleton diamine) / (weight of acid dianhydride + weight of total diamine) x 100 (%) The polyimide films prepared in the Examples and Comparative Examples were evaluated by the following test methods.

[0081] [Measurement of tensile elongation] A test piece (width 12.7 mm × length 127 mm) was cut out from the prepared polyimide film. A tensile test was performed on this test piece at 25° C. and 50 mm / min using a tension tester (Tensilon, manufactured by Orientec Co., Ltd.) to determine the tensile elongation (%).

[0082] [Measurement of moisture permeability] The moisture permeability was measured using the cup method according to JIS Z0208. The area of ​​the permeable part was 2.826×10 -3 m 2 Calcium chloride (anhydrous) was placed in an aluminum moisture permeability cup as a moisture absorbent and sealed with the prepared polyimide film. The cup was repeatedly weighed every 24 hours under test conditions of 40°C and 90 RH%, and the average mass increase of the cup was taken as the amount of water vapor that had permeated the polyimide film, and the moisture permeability (g / m) of the polyimide film was calculated. 2 24hr).

[0083] [Biological safety testing] The prepared polyimide film was evaluated according to the following biological safety test standards stipulated by the United States Pharmacopoeia (USP).

[0084] (1) Cytotoxicity test The prepared polyimide film was subjected to extraction treatment, and the presence or absence of cell decomposition in response to the extract was evaluated. In all test specimens, intracytoplasmic particles were present in a separated state, and no cell lysis was observed. Therefore, the evaluation grade was "0" (None). This result means that this polyimide film has no cytotoxicity.

[0085] (2) Systemic toxicity test The prepared polyimide film was extracted with a sodium chloride solution or sesame oil, and these extracts were administered intravenously or intraperitoneally to mice to evaluate the presence or absence of abnormalities. In this test, none of the test animals developed abnormalities, and of course none of the test animals died. Therefore, the evaluation grade was "0" (None). This result means that this polyimide film has no systemic toxicity.

[0086] (3) Intradermal toxicity test The prepared polyimide film was extracted with a sodium chloride solution or sesame oil, and these extracts were administered intradermally to rats to evaluate the presence or absence of abnormalities. In this test, none of the test animals developed abnormalities, and of course none of the test animals died. Therefore, the evaluation grade was "0" (None). This result means that this polyimide film has no intradermal toxicity.

[0087] The evaluation results of Examples 1 to 11 are shown in Tables 1 and 2, and the evaluation results of Comparative Examples 1 to 7 are shown in Table 3. The results of the Examples and Comparative Examples show that the polyimide film of the present invention is extremely excellent in tensile elongation and moisture permeability. It was also demonstrated that the polyimide film of the present invention is extremely excellent in terms of biological safety.

[0088] [Table 1]

[0089] [Table 2]

[0090] [Table 3]

[0091] Example 12 A 1000 ml separable flask was charged with acid dianhydride BTDA (0.12 mol), 200 g of N-methyl-2-pyrrolidone (NMP), and 200 g of xylene, and mixed at room temperature. Next, silicon-containing diamine A (0.096 mol) was added dropwise using a dropping funnel, followed by the addition of aromatic diamine BAPP (0.024 mol), and the mixture was stirred at room temperature for 2 hours to obtain a siloxane-containing polyimide precursor solution. This polyimide precursor solution was heated to 190°C and stirred for 20 hours to obtain a polyimide solution having a weight average molecular weight (Mw) of 55,542. This polyimide solution was applied onto a release film and dried to form a film, and the release film was peeled off to obtain a polyimide film.

[0092] [Gamma ray resistance test] The prepared polyimide film was cut in half, placed on a flat plate, and irradiated with gamma rays at an intensity of 50 kGy for two months using a gamma ray irradiator. The other half of the cut polyimide film was stored in a dark box for two months.

[0093] (1) Measurement of tensile modulus Test pieces (width 12.4 mm × length 160 mm) were cut out from the polyimide film irradiated with gamma rays and the polyimide film not irradiated with gamma rays, respectively. The tensile modulus E' of each test piece was measured at 50 mm / min under a load of 10 kg using a tension tester (Tensilon, manufactured by Orientec Co., Ltd.). The change in tensile modulus determined from the measurement results of both test pieces was 3.7%.

[0094] (2) Measurement of glass transition temperature Test pieces (width 2 mm × length 30 mm) were cut out from the polyimide film irradiated with gamma rays and the polyimide film not irradiated with gamma rays, respectively. The glass transition temperature (Tg) of each test piece was measured by TMA thermomechanical analysis using a thermomechanical analyzer (TMA4000SA, manufactured by Bruker Corporation). The change in glass transition temperature calculated from the measurement results of both test pieces was 5.8%.

[0095] From the results of Example 12, it is clear that the polyimide film of the present invention has extremely excellent gamma ray resistance. [Industrial Applicability]

[0096] The polyimide film of the present invention can be suitably used as a material for sensor devices or wearable devices. [Explanation of symbols]

[0097] 1 skin 2. Skin adhesives or skin pressure sensitive adhesives made of siloxane-containing polyimides 3, 6 Conductive layer made of metal, conductive paste or conductive polymer 4, 7 Semiconductor parts 5. Elastic substrate made of siloxane-containing polyimide 8 Solder resist made of siloxane-containing polyimide

Claims

1. A polyimide film comprising a polyimide having a structural unit derived from a diamine and a structural unit derived from an aromatic acid dianhydride, 1. A polyimide film, comprising the polyimide containing 45% by weight or more of a structural unit derived from a silicon-containing diamine represented by formula (1) based on the entire polyimide structure. 【Chemistry 1】 (In the formula, R １ and R ２ are each independently a divalent aliphatic hydrocarbon group having 3 to 20 carbon atoms; R ３ , R ４ , R ５ and R ６ are each independently a monovalent aliphatic hydrocarbon group or aromatic group having 1 to 3 carbon atoms, and m is an integer of 1 or greater.

2. 2. The polyimide film according to claim 1, which, in safety tests specified in the United States Pharmacopeia, has an evaluation grade of 0 in a cytotoxicity test, no test animals die in a systemic toxicity test, and no test animals develop abnormalities in an intradermal toxicity test.

3. 2. The polyimide film according to claim 1, wherein the polyimide contains, as a structural unit derived from an aromatic acid dianhydride, at least one structural unit derived from a dianhydride selected from the group consisting of 1,2,4,5-benzenetetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, and 3,3',4,4'-biphenyltetracarboxylic dianhydride.

4. 2. The polyimide film according to claim 1, wherein the polyimide contains, as a structural unit derived from a diamine, a structural unit derived from an aromatic diamine which is at least one selected from the group consisting of 2,2-bis(4-aminophenoxyphenyl)propane and 9,9-bis(4-aminophenyl)fluorene.

5. 2. The polyimide film according to claim 1, wherein m in the structural unit derived from the silicon-containing diamine formula (1) is 1 or 2.

6. A laminate device comprising a conductive layer laminated on one or both sides of the polyimide film according to any one of claims 1 to 5, and a semiconductor component laminated on the conductive layer.

7. A wearable device comprising the laminate device according to claim 6.

8. A method for producing a semiconductor component, comprising: a fixing step of attaching and fixing a silicon wafer to a substrate having a tacky adhesive layer provided on one side of the polyimide film according to any one of claims 1 to 5; a processing step of the silicon wafer; a dicing step of cutting the silicon wafer with the substrate attached thereto to obtain semiconductor chips; and a pick-up step of peeling the substrate from the semiconductor chips.

9. A film for fixing a silicon wafer for use in manufacturing semiconductor parts, comprising the polyimide film according to any one of claims 1 to 5 and a pressure-sensitive adhesive layer for fixing a silicon wafer provided on one side of the polyimide film.

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