laminate

Abstract

A laminate in which a polyimide film is bonded to a glass substrate, the surface free energy of the surface of the glass substrate in contact with the polyimide film being 65 mJ / m 2 Hereinafter, the proportional limit of the aforementioned polyimide film is 10 to 45 MPa.

Description

TECHNICAL FIELD

[0001] The present application relates to a laminate, and more particularly to a laminate in which a polyimide film is closely adhered to a glass substrate. BACKGROUND

[0002] Various uses of polyimide resins in the field of electrical and electronic parts and the like have been studied. For example, in order to achieve lightweight and flexibility of equipment, it is desired to replace a glass substrate used in an image display device such as a liquid crystal display or an OLED display with a plastic substrate, and research on a polyimide film suitable as this plastic substrate is being conducted.

[0003] In the case where a polyimide film is used as a substrate, depending on the use, various processes such as a sputtering process for producing an oxide semiconductor film such as an indium tin oxide (ITO) film, an etching process, and the like are performed on the polyimide film to produce an electronic circuit as a target thereon. When an electronic circuit as a target is produced on a polyimide film, in order to ensure the planarity of the polyimide film, the polyimide film is closely adhered to a hard support such as a glass plate. At this time, if the polyimide film does not closely adhere to the support, a process becomes defective. In addition, after these processes, a process of peeling the polyimide film from the support is required. This peeling process is performed after the formed body on the base material is cooled to room temperature to about 50°C.

[0004] As a method of closely adhering a polyimide film to a support, in addition to a method of adding an adhesion agent to a polyimide itself, a method of sandwiching a so-called release layer between a polyimide film and a support to ensure the adhesiveness in a process and the like are known. The release layer is used for the purpose of improving the adhesiveness of a glass plate to the release layer in a process, and making it possible to adjust the adhesiveness of a polyimide film to the release layer, and further, easily peeling from a polyimide film in a final process. As the release layer, a resin film-forming composition containing a heat-resistant polymer and the like can be cited.

[0005] As a method of peeling a polyimide film from a support, for example, the following methods are known.

[0006] (1) A method of obtaining a structure body containing a polyimide resin / support, and thereafter, ablating the interface of the polyimide resin by irradiating laser light from the support side, thereby peeling the polyimide resin (for example, refer to Patent Literature 1). As the kind of laser light, a solid (YAG) laser, a gas (UV excimer) laser, and the like are used, and a spectrum of 308 nm or the like is used.

[0007] (2) A method in which, before applying the resin composition on the support, a release layer is formed on the support, and thereafter, a structure including a polyimide resin film / release layer / support is obtained, and the polyimide resin film is mechanically peeled (for example, refer to Patent Document 2). As the release layer, there are methods using Parylene (registered trademark, manufactured by Parylene Japan K.K.), tungsten oxide; methods using mold release agents of vegetable oil-based, silicone-based, fluorine-based, alkyd-based, and the like. In addition, sometimes the laser irradiation described in the above (1) is used in combination.

[0008] In addition, Patent Document 3 discloses a method in which a resin substrate is fixed to a support substrate with an adhesive layer, an electronic component is formed on the resin substrate, and an electronic device including the electronic component and the resin substrate is peeled from the support substrate, in which method, an adhesive layer using a material that causes a decrease in adhesion to the support substrate by contact with moisture is used as a main component.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 2007-512568

[0012] Patent Document 2: Japanese Patent Application Laid-Open (JP-A) No. 2010-067957

[0013] Patent Document 3: Japanese Patent Application Laid-Open (JP-A) No. 2016-021384 SUMMARY

[0014] PROBLEMS TO BE SOLVED BY THE INVENTION

[0015] If a method in which a release layer is interposed between a polyimide film and a support to ensure tightness is used, there are adverse situations in which the release layer remains on the polyimide film after peeling, and the peeling surface lacks flatness. Therefore, a method in which a release layer is not used is desired.

[0016] In addition, in the method based on the above (1), sometimes damage is caused to the resin substrate formed on the base at the time of laser irradiation, which becomes a problem. In addition, an expensive laser irradiation device must be introduced, and there are problems in terms of cost.

[0017] In the method based on the above (2), although a laser irradiation device is not required, depending on the type of polyimide, sometimes the release layer does not sufficiently function.

[0018] In the method of Patent Document 3, in order to prevent the adhesive layer from contacting moisture so that the adhesion does not decrease, a sealing layer that seals the portion where the adhesive layer is exposed needs to be formed when the electronic component is formed.

[0019] Therefore, the present invention was made in view of this situation, and its objective is to provide a laminate that does not have the problems mentioned above, does not use a release layer, and can stably peel a polyimide film from a glass substrate.

[0020] Solution for solving the problem

[0021] Through in-depth research, the inventors discovered that polyimide-glass laminates with specific values ​​for the surface free energy of the glass substrate and the proportional limit of the polyimide film can solve the aforementioned problems. This invention is based on this insight.

[0022] That is, the present invention relates to the following solutions.

[0023] <1> A laminate comprising a polyimide film tightly bonded to a glass substrate, wherein the surface free energy of the surface of the glass substrate in contact with the polyimide film is 65 mJ / m. 2 The following limits for the proportion of the aforementioned polyimide film are 10–45 MPa.

[0024] <2> According to the above <1> The laminated body wherein the peel strength of the aforementioned polyimide film from the glass substrate is less than 20 gf / cm.

[0025] <3> According to the above <1> or <2> The laminated body wherein the thickness of the aforementioned polyimide film is 3–20 μm.

[0026] <4> According to the above <1> ~ <3> The laminate in any one of the following embodiments, wherein the polyimide resin of the aforementioned polyimide film has a structural unit A1 derived from tetracarboxylic dianhydride and a structural unit B1 derived from diamine, the structural unit A1 comprising a structural unit (A11) derived from a compound represented by formula (a11) below, and the structural unit B1 comprising a structural unit (B11) derived from a compound represented by formula (b11) below.

[0027]

[0028] <5> According to the above <4> The aforementioned stacked body, wherein the aforementioned structural unit A1 further comprises a structural unit (A12) derived from the compound shown in the following formula (a12).

[0029]

[0030] <6> According to the above <1> ~ <5> The laminate according to any one of the above-mentioned polyimide films, wherein at least one selected from the group consisting of metal films, semiconductor films and insulating films is further laminated on the aforementioned polyimide film.

[0031] <7>The laminate according to <6> above, wherein the semiconductor film is at least one selected from the group consisting of indium tin oxide, amorphous silicon, indium-gallium-zinc oxide, and low-temperature polycrystalline silicon.

[0032] <8>A method for manufacturing a laminate, wherein at least one varnish selected from the group consisting of a polyimide varnish, a polyamic acid varnish, and a varnish obtained by dissolving a copolymer having an imide repeating structural unit and a polyamic acid repeating structural unit in an organic solvent is coated on a glass substrate and dried to form a polyimide film.

[0033] In the method for manufacturing the laminate, there is at least one step selected from the group consisting of an alkali cleaning step of the glass substrate and an ozone treatment step of the glass substrate before coating the varnish, and there is a step of adjusting so that the proportional limit of the obtained polyimide film becomes 10 to 45 MPa.

[0034] <9>The method for manufacturing a laminate according to <8> above, wherein the step of adjusting so that the proportional limit of the obtained polyimide film becomes 10 to 45 MPa is a step of adding a resin additive to the varnish.

[0035] <10>The method for manufacturing a laminate according to <9> above, wherein the resin additive is at least one selected from the group consisting of a phosphate compound, an amino-modified silicone oil, and a silicone-containing polymer.

[0036] <11>A conductive film obtained by peeling off the glass substrate from the laminate according to <6> or <7> above.

[0037] Effects of the Invention

[0038] Even when the polyimide film is mechanically peeled off from the glass substrate without using a release layer, the laminate of the present invention can be easily and stably peeled off. Therefore, the laminate of the present invention can contribute to simplifying the manufacturing process of a flexible electronic device having a resin substrate and improving its yield. Detailed Embodiments

[0039] Hereinafter, an embodiment of the present invention will be described. The content of the present invention is not limited to the embodiment described below.

[0040] It should be noted that in this specification, the term "A to B" related to the description of a numerical value means "not less than A and not more than B" (when A < B) or "not more than A and not less than B" (when A > B). In addition, in the present invention, a combination of preferred modes is a more preferred mode.

[0041] [Laminate]

[0042] The laminate of the present invention is a laminate in which a polyimide film is tightly bonded on a glass substrate, wherein the surface free energy of the surface of the glass substrate in contact with the polyimide film is 65 mJ / m. 2 The following limits for the proportion of the aforementioned polyimide film are 10–45 MPa.

[0043] <Glass substrate>

[0044] If the surface free energy of the glass substrate in the laminate of the present invention that is in contact with the polyimide film is 65 mJ / m 2 The following are not particularly limited, as long as they have the strength to be sufficient to support the polyimide film when manufacturing an electronic device (conductive film) with the polyimide film as a substrate.

[0045] The surface free energy of the glass substrate in contact with the polyimide film is 65 mJ / m. 2 The preferred value is 60 mJ / m 2 The preferred value is 58 mJ / m 2 The following is a further preferred value: 57 mJ / m 2 The following is also preferred. Additionally, 30 mJ / m² is preferred. 2 above.

[0046] There are no particular restrictions on the type of glass; alkali-free glass (borosilicate glass), alkali glass, sodium glass, non-fluorescent glass, phosphate glass, borate glass, quartz, etc., can be used.

[0047] To improve adhesion to the polyimide film, a high degree of flatness on the upper surface of the glass substrate is preferred. Specifically, the surface roughness Rmax is preferably 10 μm or less, and more preferably 1 μm or less.

[0048] <Polyimide film>

[0049] In the laminate of the present invention, a polyimide film is adhered to a glass substrate. Preferably, the polyimide film is directly adhered to the glass substrate, and preferably, no adhesive layer or the like is sandwiched between the glass substrate and the polyimide film.

[0050] The polyimide film used in the laminate of the present invention has a ratio limit of 10-45 MPa, preferably 20-45 MPa, more preferably 25-45 MPa, and even more preferably 25-40 MPa.

[0051] It can be considered that by setting the aforementioned proportional limit to 10 MPa or more, it has the strength necessary for peeling or use, and by setting the aforementioned proportional limit to 45 MPa or less, it has the softness necessary for deformation during peeling.

[0052] Here, the proportional limit is as follows. In the tensile test of polyimide film, at the beginning of the tensile test, the stress changes linearly with respect to strain. In other words, the stress is proportional to the strain. The maximum stress within this proportional range is called the proportional limit. The proportional limit can be determined by tensile testing based on JIS K7127:1999, and specifically, it can be determined according to the method described in the examples.

[0053] If the proportional limit of the polyimide film is within the aforementioned range, the film can be stably peeled off from the glass substrate without the use of a release layer. The reason for this is not yet certain, but it can be assumed that the film is peeled off after undergoing bending deformation, therefore, the proportional limit is moderately small, and thus, it is easy to bend and easy to peel off.

[0054] The thickness of the polyimide film is preferably 3–20 μm, more preferably 4–15 μm, and even more preferably 5–10 μm. If the thickness of the polyimide film is within this range, the polyimide film will not be damaged during the manufacture of electronic devices, making it easier to manufacture the devices. After the electronic devices are manufactured, they can be stably peeled off from the glass substrate. It should be noted that the thickness of the polyimide film can also be determined by physical measurement using a micrometer or similar means, or by optical observation using a laser microscope or similar means, measuring the height of the upper surface of the film in contact with the glass.

[0055] The peel strength of the polyimide film from the glass substrate is preferably 20 gf / cm or less, more preferably 15 gf / cm or less, even more preferably 10 gf / cm or less, even more preferably 9 gf / cm or less, and even more preferably 7 gf / cm or less. If the peel strength is within this range, the polyimide film adheres tightly to the glass substrate without peeling during the manufacture of the electronic device, and can be stably peeled off from the glass substrate after the manufacture of the electronic device.

[0056] The polyimide film used in the laminate of the present invention may consist solely of polyimide resin or may contain various additives. Examples of additives include resin additives and various additives described in the description of each varnish described later; the polyimide film preferably contains resin additives.

[0057] Preferred resin additives include phosphate ester compounds, amino-modified silicone oils, silicone-containing polymers, acrylic polymers, and fluoropolymers, with at least one selected from the group consisting of phosphate ester compounds, amino-modified silicone oils, and silicone-containing polymers being more preferred. From the viewpoint of reducing the peel strength of the laminate, it is preferable to use two or more resin additives in combination, more preferably to use a combination of phosphate ester compounds and silicone-containing polymers, and even more preferably to use a combination of phosphate ester compounds, amino-modified silicone oils, and silicone-containing polymers.

[0058] As a phosphate ester compound, it is preferably an acidic phosphate ester compound, and more preferably dibutyl phosphate.

[0059] By including additives, the proportion limit can be reduced, and the proportion limit can be set to the aforementioned range.

[0060] The content of the additive relative to the polyimide resin constituting the polyimide film is preferably 0.01 to 0.7% by mass, more preferably 0.05 to 0.5% by mass, and even more preferably 0.05 to 0.2% by mass.

[0061] Especially when using phosphate ester compounds, the amount of polyimide resin constituting the polyimide film is preferably 0.01 to 0.7% by mass, more preferably 0.01 to 0.3% by mass, and even more preferably 0.01 to 0.1% by mass.

[0062] Furthermore, when using amino-modified silicone oil, the amount of polyimide resin constituting the polyimide film is preferably 0.3 to 0.7% by mass, more preferably 0.3 to 0.6% by mass, and even more preferably 0.3 to 0.5% by mass.

[0063] Furthermore, when using a polymer containing organosilicon, the amount of polyimide resin constituting the polyimide film is preferably 0.05 to 0.7% by mass, more preferably 0.05 to 0.3% by mass, and even more preferably 0.05 to 0.1% by mass.

[0064] When the polyimide film contains resin additives, the content of the polyimide resin constituting the polyimide film is preferably 99.3 to 99.99% by mass, more preferably 99.5 to 99.95% by mass, and even more preferably 99.8 to 99.95% by mass.

[0065] Next, preferred examples of polyimide resins that can be used in the polyimide film used in the laminate of the present invention are shown, but the present invention is not limited thereto.

[0066] Of the polyimide resin 1 and polyimide resin 2 listed below, polyimide resin 1 is preferred from the viewpoint of ease of peeling. It should be noted that polyimide resin 2 is preferably obtained by imidizing a copolymer 2 having repeating imide structural units and repeating ammonium acid structural units.

[0067] [Polyimide Resin 1]

[0068] The polyimide resin 1 has a structural unit A1 derived from tetracarboxylic dianhydride and a structural unit B1 derived from diamine, wherein structural unit A1 contains a structural unit (A11) derived from the compound shown in formula (a11) below, and structural unit B1 contains a structural unit (B11) derived from the compound shown in formula (b11) below.

[0069]

[0070] <Structural Unit A1>

[0071] Structural unit A1 is a structural unit derived from tetracarboxylic acid dianhydride contained in polyimide resin 1, which contains structural units (A11) derived from the compound shown in formula (a11) below.

[0072]

[0073] The compound shown in formula (a11) is 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride.

[0074] The structural unit (A11) can improve colorless transparency and optical isotropy.

[0075] The ratio of structural units (A11) in structural unit A1 is preferably 5 mol% or more, more preferably 20 mol% or more, further preferably 50 mol% or more, further preferably 70 mol% or more, and even more preferably 90 mol% or more. The upper limit of the ratio of structural units (A11) is not particularly limited, but is 100 mol% or less. Structural unit A1 may consist solely of structural units (A11).

[0076] Structural unit A1 preferably further comprises structural unit (A12) derived from the compound shown in formula (a12) below.

[0077]

[0078] The compound shown in formula (a12) is 4,4'-oxybisphthalic anhydride.

[0079] By incorporating both structural units (A11) and (A12) into structural unit A1, the colorless transparency, optical isotropy, and chemical resistance of the thin film can be improved. Structural unit (A12) makes a particularly significant contribution to improving chemical resistance.

[0080] When structural unit A1 includes both structural unit (A11) and structural unit (A12), the ratio of structural unit (A11) in structural unit A1 is preferably 5 to 95 mol%, more preferably 15 to 95 mol%, further preferably 20 to 90 mol%, even more preferably 50 to 90 mol%, and particularly preferably 70 to 90 mol%.

[0081] The ratio of structural units (A12) in structural unit A1 is preferably 5 to 95 mol%, more preferably 5 to 85 mol%, further preferably 10 to 80 mol%, even more preferably 10 to 50 mol%, and particularly preferably 10 to 30 mol%.

[0082] The total ratio of structural units (A11) to (A12) in structural unit A1 is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. There is no particular upper limit to the total ratio of structural units (A11) to (A12), but it is 100 mol% or less. Structural unit A1 may consist only of structural units (A11) and (A12).

[0083] Structural unit A1 may contain structural units other than structural units (A11) and (A12). There are no particular limitations on the tetracarboxylic dianhydrides that provide such structural units, and examples include aromatic tetracarboxylic dianhydrides such as pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, and 4,4'-(hexafluoroisopropylidene)bisphthalic anhydride; alicyclic tetracarboxylic dianhydrides such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride and norbornane-2-spiro-α-cyclopentanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic dianhydride; and aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride.

[0084] It should be noted that, in this specification, aromatic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride containing one or more aromatic rings, alicyclic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride containing one or more alicyclic rings but without aromatic rings, and aliphatic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride without aromatic rings or alicyclic rings.

[0085] The structural units included in structural unit A1 (i.e., structural units other than structural units (A11) and (A12)) can be one type or two or more types.

[0086] <Structural Unit B1>

[0087] Structural unit B1 is a diamine-derived structural unit contained in a polyimide resin, which contains structural units (B11) derived from the compound shown in formula (b11) below.

[0088]

[0089] The compound shown in formula (b11) is 3,3'-diaminodiphenyl sulfone.

[0090] By incorporating structural unit B1 into structural unit (B11), the optical isotropy and chemical resistance of the thin film can be improved.

[0091] The ratio of structural units (B11) in structural unit B1 is preferably 5 mol% or more, more preferably 20 mol% or more, further preferably 50 mol% or more, even more preferably 70 mol% or more, and even more preferably 80 mol% or more. The upper limit of the ratio of structural units (B11) is not particularly limited, but is 100 mol% or less. Structural unit B1 may consist solely of structural units (B11).

[0092] Structural unit B1 preferably further comprises structural unit (B12). Structural unit (B12) is preferably selected from at least one of the following: structural unit (B121) derived from the compound shown in formula (b121), structural unit (B122) derived from the compound shown in formula (b122), structural unit (B123) derived from the compound shown in formula (b123), structural unit (B124) derived from the compound shown in formula (b124), and structural unit (B125) derived from the compound shown in formula (b125).

[0093] More preferably, it is a structural unit (B121) derived from the compound shown in formula (b121) and a structural unit (B122) derived from the compound shown in formula (b122), and even more preferably, it is a structural unit (B121) derived from the compound shown in formula (b121).

[0094]

[0095] (In formula (b124), R can be a hydrogen atom, a fluorine atom, or a methyl group.)

[0096] The compound shown in formula (b121) is 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane.

[0097] By including structural unit (B121) in structural unit B1, the colorless transparency of the film can be improved.

[0098] The compound shown in formula (b122) is bis[4-(4-aminophenoxy)phenyl] sulfone.

[0099] By including structural unit (B122) in structural unit B1, the tensile elongation of the film can be improved.

[0100] The compound shown in formula (b123) is 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA).

[0101] By including structural unit (B123) in structural unit B1, the colorless transparency of the film can be improved.

[0102] In formula (b124), R is independently selected from the group consisting of hydrogen atoms, fluorine atoms, and alkyl groups having 1 to 5 carbon atoms, and is a hydrogen atom, a fluorine atom, or a methyl group, preferably a hydrogen atom. Examples of compounds represented by formula (b124) include 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(3-fluoro-4-aminophenyl)fluorene, and 9,9-bis(3-methyl-4-aminophenyl)fluorene, preferably at least one of these three compounds, preferably 9,9-bis(4-aminophenyl)fluorene.

[0103] By incorporating structural unit B1 into structural unit (B124), the optical isotropy and heat resistance of the thin film can be improved.

[0104] The compound shown in formula (b125) is 2,2'-bis(trifluoromethyl)benzidine.

[0105] By incorporating structural unit B1 into structural unit (B125), the colorless transparency, chemical resistance, and mechanical properties of the film can be improved.

[0106] Structural element (B12) can be only structural element (B121), or only structural element (B122), or only structural element (B123), or only structural element (B124), or only structural element (B125).

[0107] In addition, structural unit (B12) can be a combination of two or more structural units selected from the group consisting of structural units (B121) to (B125).

[0108] When structural unit B1 includes both structural unit (B11) and structural unit (B12), the ratio of structural unit (B11) in structural unit B1 is preferably 5-95 mol%, more preferably 15-95 mol%, further preferably 20-90 mol%, even more preferably 50-90 mol%, and particularly preferably 70-90 mol%.

[0109] The ratio of structural units (B12) in structural unit B1 is preferably 5-95 mol%, more preferably 5-85 mol%, further preferably 10-80 mol%, even more preferably 10-50 mol%, and particularly preferably 10-30 mol%.

[0110] The total ratio of structural units (B11) to (B12) in structural unit B1 is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. There is no particular upper limit to the total ratio of structural units (B11) to (B12), but it is 100 mol% or less. Structural unit B1 may consist only of structural units (B11) and (B12).

[0111] Structural unit B1 may contain structural units other than structural units (B11) and (B12). The diamine providing such a structural unit is not particularly limited, and examples include 1,4-phenylenediamine, p-phenylenediamine, 3,5-diaminobenzoic acid, 1,5-diaminonaphthalene, 2,2'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzoyl aniline, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, α,α'-bis(4- Aromatic diamines such as (b-11)-1,4-diisopropylbenzene, N,N'-bis(4-aminophenyl)terephthalamide, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 4,4'-diamino-2,2'-bistrifluoromethyl diphenyl ether (excluding compounds shown in formula (b-11)); alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine.

[0112] It should be noted that, in this specification, aromatic diamines refer to diamines containing one or more aromatic rings, alicyclic diamines refer to diamines containing one or more alicyclic rings but not aromatic rings, and aliphatic diamines refer to diamines that do not contain either aromatic or alicyclic rings.

[0113] The structural units included in structural unit B1 (i.e., structural units other than structural units (B11) and (B12)) can be one type or two or more types.

[0114] From the viewpoint of the mechanical strength of the resulting polyimide film, the number-average molecular weight of polyimide resin 1 is preferably 5,000 to 200,000. It should be noted that the number-average molecular weight of the polyimide resin can be determined, for example, by conversion based on standard polymethyl methacrylate (PMMA) values ​​determined by gel filtration chromatography.

[0115] The polyimide resin 1 may contain structures other than the polyimide chain (a structure formed by imide bonding of structural unit A1 and structural unit B1). Examples of structures other than the polyimide chain that may be included in the polyimide resin include, for example, structures containing amide bonds.

[0116] The polyimide resin 1 preferably comprises a polyimide chain (a structure formed by imide bonding of structural unit A1 and structural unit B1) as the main structure. Therefore, the proportion of the polyimide chain in the polyimide resin 1 is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, particularly preferably 99% by mass or more, and less than 100% by mass.

[0117] [Manufacturing method of polyimide resin 1]

[0118] Polyimide resin 1 can be manufactured by reacting a tetracarboxylic acid component containing a compound providing the above-mentioned structural unit (A11) with a diamine component containing a compound providing the above-mentioned structural unit (B11).

[0119] The tetracarboxylic acid component may include a compound that provides the aforementioned structural unit (A12). Additionally, the diamine component preferably includes a compound that provides the aforementioned structural unit (B12).

[0120] Compounds providing the structural unit (A11) can include those shown in formula (a11), but are not limited thereto; derivatives thereof can be derived from compounds providing the same structural unit. Examples of such derivatives include tetracarboxylic acids (i.e., 1,2,4,5-cyclohexanetetracarboxylic acid) and alkyl esters of the tetracarboxylic acid corresponding to the tetracarboxylic acid dianhydride shown in formula (a11). Preferably, the compound shown in formula (a11) (i.e., the dianhydride) is preferred.

[0121] Similarly, compounds providing the structural unit (A12) can be listed as those shown in formula (a12), but are not limited thereto; derivatives thereof can be found within the range of providing the same structural unit. Examples of such derivatives include tetracarboxylic acids and alkyl esters of the tetracarboxylic acid corresponding to the tetracarboxylic dianhydride shown in formula (a12). The compound providing the structural unit (A12) is preferably the compound shown in formula (a12) (i.e., the dianhydride).

[0122] The tetracarboxylic acid component preferably comprises 5 mol% or more, more preferably 20 mol% or more, further preferably 50 mol% or more, further preferably 70 mol% or more, and even more preferably 90 mol% or more of a compound providing a structural unit (A11). The upper limit of the percentage of the compound providing the structural unit (A11) is not particularly limited, and includes 100 mol% or less.

[0123] When the tetracarboxylic acid component comprises both a compound providing structural unit (A11) and a compound providing structural unit (A12), it preferably comprises 5 to 95 mol%, more preferably 15 to 95 mol%, further preferably 20 to 90 mol%, even more preferably 50 to 90 mol%, and particularly preferably 70 to 90 mol% of the compound providing structural unit (A11). Additionally, it preferably comprises 5 to 95 mol%, more preferably 5 to 85 mol%, further preferably 10 to 80 mol%, even more preferably 10 to 50 mol%, and particularly preferably 10 to 30 mol% of the compound providing structural unit (A12).

[0124] In the tetracarboxylic acid component, the total content of the compound providing the structural unit (A11) and the compound providing the structural unit (A12) is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the total content ratio of the compound providing the structural unit (A11) to the compound providing the structural unit (A12) is not particularly limited, but is 100 mol% or less. The tetracarboxylic acid component may consist solely of the compound providing the structural unit (A11) and the compound providing the structural unit (A12).

[0125] Tetracarboxylic acid components may include compounds other than those providing structural units (A11) and those providing structural units (A12). Examples of such compounds include the aforementioned aromatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aliphatic tetracarboxylic dianhydrides, as well as their derivatives (tetracarboxylic acids, alkyl esters of tetracarboxylic acids, etc.).

[0126] The tetracarboxylic acid component may optionally include one or more compounds (i.e., compounds other than those providing structural unit (A11) and those providing structural unit (A12)).

[0127] As the compound providing the structural unit (B11), compounds represented by formula (b11) can be listed, but are not limited thereto; derivatives thereof may be used within the range of providing the same structural unit. As such derivatives, diisocyanates corresponding to the diamine represented by formula (b11) can be listed. As the compound providing the structural unit (B11), the compound represented by formula (b11) (i.e., the diamine) is preferred.

[0128] Examples of compounds providing the structural unit (B12) include compounds of formula (b121), (b122), (b123), (b124), and (b125), but are not limited thereto; derivatives thereof may be derived from these compounds within the scope of providing the same structural unit. Examples of such derivatives include diisocyanates corresponding to these diamines. Diamines are preferred as compounds providing the structural unit (B12).

[0129] The diamine component preferably comprises 5 mol% or more, more preferably 20 mol% or more, further preferably 50 mol% or more, even more preferably 70 mol% or more, and even more preferably 80 mol% or more of a compound that provides the structural unit (B11). There is no particular upper limit to the percentage of the compound providing the structural unit (B11), and it includes 100 mol% or less.

[0130] When the diamine component comprises both a compound providing structural unit (B11) and a compound providing structural unit (B12), it preferably comprises 5 to 95 mol%, more preferably 15 to 95 mol%, further preferably 20 to 90 mol%, even more preferably 50 to 90 mol%, and particularly preferably 70 to 90 mol% of the compound providing structural unit (B11). Additionally, it preferably comprises 5 to 95 mol%, more preferably 5 to 85 mol%, further preferably 10 to 80 mol%, even more preferably 10 to 50 mol%, and particularly preferably 10 to 30 mol% of the compound providing structural unit (B12).

[0131] In the diamine component, the total content of the compound providing the structural unit (B11) and the compound providing the structural unit (B12) is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. There is no particular upper limit to the ratio of the compound providing the structural unit (B11) to the total content of the compound providing the structural unit (B12), and it includes 100 mol% or less. The diamine component may consist solely of the compound providing the structural unit (B11) and the compound providing the structural unit (B12).

[0132] The diamine component may include compounds other than those providing structural unit (B11) and those providing structural unit (B12). Examples of such compounds include the aromatic diamines, alicyclic diamines and aliphatic diamines, as well as their derivatives (diisocyanates, etc.).

[0133] The diamine component may contain one or more compounds (i.e., compounds other than those providing structural unit (B11) and those providing structural unit (B12)).

[0134] Regarding the ratio of tetracarboxylic acid component to diamine component used in the manufacture of polyimide resin 1, the preferred molar ratio of diamine component to tetracarboxylic acid component 1 is 0.9 to 1.1 moles.

[0135] In addition to the aforementioned tetracarboxylic acid component and diamine component, a capping agent may also be used in the manufacture of polyimide resin 1. Monoamines or dicarboxylic acids are preferred as capping agents. The amount of capping agent added is preferably 0.0001 to 0.1 mol relative to 1 mole of the tetracarboxylic acid component, and particularly preferably 0.001 to 0.06 mol. Examples of monoamine capping agents include methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, and 4-methylaniline. Among these, benzylamine and aniline are suitable. Dicarboxylic acid capping agents are preferred, as a portion of them can be ring-closed. Recommended alternatives include phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid. Among these, phthalic acid and phthalic anhydride are suitable choices.

[0136] There are no particular limitations on the method for reacting the aforementioned tetracarboxylic acid component with the diamine component; any known method may be used.

[0137] Specific reaction methods include: (1) adding tetracarboxylic acid, diamine and reaction solvent into a reactor, stirring at 10-110°C for 0.5-30 hours, and then raising the temperature to carry out an imidization reaction; (2) adding diamine and reaction solvent into a reactor to dissolve them, then adding tetracarboxylic acid, stirring at 10-110°C for 0.5-30 hours as needed, and then raising the temperature to carry out an imidization reaction; (3) adding tetracarboxylic acid, diamine and reaction solvent into a reactor, and immediately raising the temperature to carry out an imidization reaction, etc.

[0138] The reaction solvent used to manufacture polyimide resin 1 only needs to be able to dissolve the resulting polyimide resin without hindering the imidization reaction. Examples include aprotic solvents, phenolic solvents, ether solvents, and carbonate solvents.

[0139] Specific examples of aprotic solvents include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolium ketone, and tetramethylurea; lactone solvents such as γ-butyrolactone and γ-valerolactone; phosphorus-containing amide solvents such as hexamethylphosphoramide and hexamethylphosphonitramide; sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; ketone solvents such as acetone, cyclohexanone, and methylcyclohexanone; amine solvents such as methylpyridine and pyridine; and ester solvents such as (2-methoxy-1-methylethyl) acetate.

[0140] Specific examples of phenolic solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol.

[0141] Specific examples of ether-based solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl] ether, tetrahydrofuran, and 1,4-dioxane.

[0142] In addition, specific examples of carbonate-based solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate.

[0143] Among the above-mentioned reaction solvents, amide-based solvents or lactone-based solvents are preferred. Furthermore, two or more of the above-mentioned reaction solvents may be used alone or in combination.

[0144] In the imidization reaction, a Dean-Stark apparatus or similar device is preferably used to remove water generated during manufacturing while carrying out the reaction. By performing this operation, the degree of polymerization and the imidization rate can be further improved.

[0145] In the above imidization reaction, known imidization catalysts can be used. Examples of imidization catalysts include base catalysts and acid catalysts.

[0146] Examples of base catalysts include organic base catalysts such as pyridine, quinoline, isoquinoline, α-methylpyridine, β-methylpyridine, 2,4-dimethylpyridine, 2,6-dimethylpyridine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, and N,N-diethylaniline; and inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate.

[0147] In addition, examples of acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, and naphthalenesulfonic acid. These imidization catalysts can be used alone or in combination of two or more.

[0148] From a processability point of view, the use of a base catalyst is preferred, the use of an organic base catalyst is more preferred, the use of triethylamine is even more preferred, and the use of a combination of triethylamine and triethylenediamine is particularly preferred.

[0149] From the viewpoint of suppressing reaction rate and gelation, the temperature of the imidization reaction is preferably 120–250°C, more preferably 160–200°C. Furthermore, the reaction time is preferably 0.5–10 hours after the initial distillation of water.

[0150] The concentration of solid components during the imidization reaction is preferably 30–60% by mass, more preferably 35–58% by mass, and particularly preferably 40–56% by mass. If the concentration of solid components during the imidization reaction is within this range, the imidization reaction can be carried out easily and well, and the water generated during the reaction can be easily removed. Therefore, the degree of polymerization and the imidization rate can be improved.

[0151] The concentration of the solid component during the imidization reaction is calculated based on the following formula and the mass of the tetracarboxylic acid component added to the reaction system, the diamine component in the reaction system, and the reaction solvent.

[0152] Solid component concentration (mass%) during imidization reaction = (total mass of tetracarboxylic acid and diamine components) / (total mass of tetracarboxylic acid, diamine, and reaction solvent) × 100

[0153] [Polyimide resin 2 and copolymer 2]

[0154] Polyimide resin 2 is a polyimide resin obtained by imidizing copolymer 2 having repeating imide structural units and repeating ammonium acid structural units. Hereinafter, copolymer 2 will be described, and the polyimide film used in the laminate of the present invention uses polyimide resin 2 obtained by imidizing copolymer 2.

[0155] Copolymer 2 is a precursor of polyimide resin 2, preferably comprising:

[0156] It has an imide repeating structural unit with structural unit A2i derived from tetracarboxylic dianhydride and structural unit B2i derived from diamine; and

[0157] It has repeating amide acid structural units, with structural unit A2a derived from tetracarboxylic dianhydride and structural unit B2a derived from diamine.

[0158] The structural unit A2, which contains the aforementioned structural units A2i and A2a, includes a structural unit (A21) derived from tetracarboxylic dianhydride (a21).

[0159] Structural unit B2, which includes the aforementioned structural units B2i and B2a, comprises structural unit (B21) derived from the compound shown in formula (b21) below.

[0160] The structural unit (A21) comprises at least one selected from the group consisting of a structural unit (A211) derived from a compound represented by formula (a211), a structural unit (A212) derived from a compound represented by formula (a212), a structural unit (A213) derived from a compound represented by formula (a213), and a structural unit (A214) derived from a compound represented by formula (a214).

[0161]

[0162] <Structural Unit A2>

[0163] Structural unit A2 is a structural unit derived from tetracarboxylic dianhydride contained in copolymer 2, which contains structural units (A21) derived from tetracarboxylic dianhydride (a21).

[0164] From the viewpoint of high heat resistance and low residual stress, the structural unit (A21) includes at least one of the following: structural unit (A211) derived from the compound shown in formula (a211), structural unit (A212) derived from the compound shown in formula (a212), structural unit (A213) derived from the compound shown in formula (a213), and structural unit (A214) derived from the compound shown in formula (a214).

[0165] It should be noted that the structural unit (A21) is included in the structural unit A2i derived from tetracarboxylic acid dianhydride contained in the imide repeating structural unit, and the structural unit A2a derived from tetracarboxylic acid dianhydride contained in the amide repeating structural unit also preferably includes the structural unit (A21).

[0166]

[0167] The compound represented by formula (a211) is a biphenyltetracarboxylic acid dianhydride (BPDA). Specific examples include 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA) represented by formula (a211s), 2,3,3',4'-biphenyltetracarboxylic acid dianhydride (a-BPDA) represented by formula (a211a), and 2,2',3,3'-biphenyltetracarboxylic acid dianhydride (i-BPDA) represented by formula (a211i). Among these, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA) represented by formula (a211s) is preferred.

[0168]

[0169] The compound represented by formula (a212) is p-phenylene bis(trimethoxylate) dianhydride (TAHQ).

[0170] The compound represented by formula (a213) is an oxydiphthalic anhydride (ODPA). Specific examples include 4,4'-oxydiphthalic anhydride (s-ODPA) represented by formula (a213s), 3,4'-oxydiphthalic anhydride (a-ODPA) represented by formula (a213a), and 3,3'-oxydiphthalic anhydride (i-ODPA) represented by formula (a213i). Among these, 4,4'-oxydiphthalic anhydride (s-ODPA) represented by formula (a213s) is preferred.

[0171]

[0172] The compound represented by formula (a214) is pyromellitic dianhydride (PMDA).

[0173] From the viewpoint of high heat resistance and low residual stress, the structural unit (A21) preferably includes at least one selected from the group consisting of structural unit (A211) and structural unit (A212). More preferably, it includes structural unit (A211).

[0174] From the viewpoint of improving the heat resistance and thermal stability of the film and further reducing residual stress, structural unit (A211) is preferred, and from the viewpoint of reducing YI and improving colorless transparency, structural unit (A212) is preferred.

[0175] The ratio of structural unit (A21) in structural unit A2 is preferably 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. There is no particular upper limit to this ratio, but it is 100 mol% or less. Structural unit (A21) may consist of at least one type selected from structural units (A211) to (A214), or may be composed solely of any one type selected from structural units (A211) to (A214).

[0176] The ratio of structural unit (A21) in structural unit A2i is preferably 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. There is no particular upper limit to this ratio, but it is 100 mol% or less. Structural unit (A21) may consist of at least one of structural units (A211) to (A214), or may be composed solely of any one of structural units (A211) to (A214).

[0177] The ratio of structural unit (A21) in structural unit A2a is preferably 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. There is no particular upper limit to this ratio, but it is 100 mol% or less. Structural unit (A21) may consist of at least one of structural units (A211) to (A214), or may be composed solely of any one of structural units (A211) to (A214).

[0178] Structural unit A2 may contain structural units other than structural unit (A21). There are no particular limitations on the tetracarboxylic dianhydrides that provide such structural units, but examples include aromatic tetracarboxylic dianhydrides such as 4,4'-(hexafluoroisopropylidene)bisphthalic anhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, and 2,2',3,3'-benzophenone tetracarboxylic dianhydride; norbornane-2-spiro-α-cyclopentanone-α'-spiro-2”-norbornane-5,5”,6” Alicyclic tetracarboxylic dianhydrides include 6”-tetracarboxylic dianhydrides, 1,2,3,4-cyclobutanetetracarboxylic dianhydrides, 1,2,3,4-cyclopentanetetracarboxylic dianhydrides, 1,2,4,5-cyclohexanetetracarboxylic dianhydrides, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydrides, and dicyclohexyltetracarboxylic dianhydrides; and aliphatic tetracarboxylic dianhydrides include 1,2,3,4-butanetetracarboxylic dianhydrides. Among these, aromatic tetracarboxylic dianhydrides are preferred.

[0179] The structural units included in structural unit A2 (i.e., structural units other than structural unit (A21)) can be a single type or a combination of two or more types.

[0180] <Structural Unit B2>

[0181] Structural unit B2 is a diamine-derived structural unit contained in the copolymer of the present invention, which contains structural units (B21) derived from the compound shown in formula (b21) below. By including structural unit (B21) in structural unit B2, excellent transparency is achieved, while also maintaining the characteristics of low residual stress and low retardation.

[0182] The structural unit (B21) is contained in the structural unit derived from the diamine-derived structural unit B2i contained in the imide repeating structural unit.

[0183]

[0184] The compound shown in formula (b21) is the same as the compound shown in formula (b123) above, and is 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA).

[0185] By including structural unit (B21) in structural unit B2, the colorless transparency of the film can be improved.

[0186] Structural unit B2 preferably further comprises structural unit (B22) derived from the compound shown by the following general formula (b22). By including structural unit (B22) in structural unit B2, the scaling limit can be reduced.

[0187] It should be noted that the structural unit (B22) is preferably contained in the diamine-derived structural unit B2a contained in the amyl acid repeating structural unit.

[0188]

[0189] In equation (b22), Z 1 and Z 2 Each can independently represent either a divalent aliphatic group or a divalent aromatic group containing an oxygen atom; R 1 and R 2 Each independently represents a monovalent aromatic group or a monovalent aliphatic group; R 3 and R 4 Each independently represents a monovalent aliphatic group; R 5 and R 6 Each of them independently represents a monovalent aliphatic group or a monovalent aromatic group; m and n each independently represent integers greater than or equal to 1; the sum of m and n represents an integer from 2 to 1000.

[0190] It should be noted that in equation (b22), the two or more different repeating units recorded in [] are not limited to the order of [], and can be repeated in any form and order, such as random, alternating or segmental.

[0191] In equation (b22), Z 1 and Z 2 The divalent aliphatic or divalent aromatic group may optionally be replaced by a fluorine atom. Examples of divalent aliphatic groups include divalent saturated or unsaturated aliphatic groups with 1 to 20 carbon atoms, and aliphatic groups containing oxygen atoms. The number of carbon atoms in the divalent aliphatic group is preferably 3 to 20.

[0192] As divalent saturated aliphatic groups, alkylene groups with 1 to 20 carbon atoms can be listed, such as methylene, ethylene, propylene, trimethylene, tetramethylene, hexamethylene, octamethylene, decamethylene, dodecamethylene, etc.

[0193] As divalent unsaturated aliphatic groups, alkenyl groups with 2 to 20 carbon atoms can be listed, such as vinylidene, propenylidene, and alkenyl groups with unsaturated double bonds at the end.

[0194] Examples of aliphatic groups containing oxygen atoms include alkeneoxy groups and aliphatic groups with ether bonds.

[0195] Examples of alkene oxides include propoxides and trimethylene oxides.

[0196] Examples of divalent aromatic groups include arylene groups with 6 to 20 carbon atoms and arylene alkyl groups with 7 to 20 carbon atoms. As Z... 1 and Z 2 Specific examples of arylene groups with 6 to 20 carbon atoms include o-phenylene, meta-phenylene, para-phenylene, 4,4'-biphenylene, and 2,6-naphthylene.

[0197] As Z 1 and Z 2 The preferred form is trimethylene or p-phenylene, and the more preferred form is trimethylene.

[0198] In equation (b22), R is... 1 ~R 6 The monovalent aliphatic group in the group can be either a monovalent saturated or unsaturated aliphatic group. Examples of monovalent saturated aliphatic groups include alkyl groups with 1 to 22 carbon atoms, such as methyl, ethyl, and propyl. Examples of monovalent unsaturated aliphatic groups include alkenyl groups with 2 to 22 carbon atoms, such as vinyl and propenyl. These groups may optionally be substituted with fluorine atoms.

[0199] R as in equation (b22) 1 R 2 R 5 and R 6 Examples of monovalent aromatic groups include aryl groups with 6 to 20 carbon atoms, aryl groups with 7 to 30 carbon atoms that are substituted with alkyl groups, and aralkyl groups with 7 to 30 carbon atoms. Aryl groups are preferred as monovalent aromatic groups, and phenyl groups are more preferred.

[0200] R 1 and R 2 At least one of them is preferably a monovalent aromatic group, more preferably R 1 and R 2 All are monovalent aromatic groups, with R being further preferred. 1 and R 2 All are phenyl.

[0201] As R 3 and R 4 Preferably, it is an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group.

[0202] As R 5 and R 6 Preferably, it is a monovalent aliphatic group, and more preferably a methyl group.

[0203] As described above, among the compounds represented by the general formula (b22), the compounds represented by the following formula (b221) are preferred.

[0204]

[0205] (In equation (b221), m and n have the same meanings as m and n in equation (b22), and the preferred ranges are also the same.)

[0206] In formulas (b22) and (b221), m represents the number of repetitions of siloxane units bonded by at least one monovalent aromatic group, and n represents the number of repetitions of siloxane units bonded by a monovalent aliphatic group.

[0207] In equations (b22) and (b221), m and n each independently represent integers greater than or equal to 1, and the sum of m and n (m+n) represents an integer from 2 to 1000. The sum of m and n preferably represents an integer from 3 to 500, more preferably from 3 to 100, and even more preferably from 3 to 50.

[0208] The m / n ratio in formulas (b22) and (b221) is preferably 5 / 95 to 50 / 50, more preferably 10 / 90 to 40 / 60, and even more preferably 20 / 80 to 30 / 70.

[0209] The functional group equivalent (amine equivalent) of the compound shown in formula (b22) is preferably 150 to 5,000 g / mol, more preferably 400 to 4,000 g / mol, and even more preferably 500 to 3,000 g / mol.

[0210] It should be noted that the functional group equivalent refers to the mass of the compound represented by formula (b22) per mole of functional group (amino group).

[0211] Among the compounds represented by the above general formula (b22), those that can be obtained in the form of commercially available products include "X-22-9409", "X-22-1660B", "X-22-161A", and "X-22-161B" manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[0212] The ratio of structural unit (B22) in structural unit B is preferably 1 to 10 mol%, more preferably 2 to 5 mol%.

[0213] The content of the polyorganosiloxane unit relative to the total of structural unit A2 and structural unit B2 is preferably 5 to 45% by mass, more preferably 7 to 40% by mass, and even more preferably 10 to 35% by mass. If the content of the polyorganosiloxane unit is within the aforementioned range, it is possible to achieve a higher balance between low retarding effect and low residual stress.

[0214] The polyorganosiloxane unit has the same meaning as the structural unit (B22). The content of the polyorganosiloxane unit relative to the sum of structural units A2 and B2 is calculated based on the mass ratio of the amount of the compound providing structural unit (B22), preferably the compound shown in formula (b22), relative to the total amount of raw materials providing structural units A2 and B2.

[0215] Structural unit B2i preferably includes structural unit (B21), and the ratio of structural unit (B21) in structural unit B2i is preferably 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. There is no particular upper limit to this ratio, but it is 100 mol% or less. Structural unit B2i may consist solely of structural unit (B21).

[0216] Structural unit B2a preferably includes structural unit (B22), and the ratio of structural unit (B22) in structural unit B2a is preferably 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. There is no particular upper limit to this ratio, but it is 100 mol% or less. Structural unit B2a may consist solely of structural unit (B22).

[0217] Structural unit B2 may contain structural units other than structural units (B21) and (B22).

[0218] The diamine providing this structural unit is not particularly limited, and examples include 1,4-phenylenediamine, p-phenylenediamine, 3,5-diaminobenzoic acid, 1,5-diaminonaphthalene, 2,2'-dimethylbiphenyl-4,4'-diamine, 2,2'-bis(trifluoromethyl)benzidine, 2,2'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzoyl aniline, 3,4'-diaminodiphenyl ether, and 1-(4-aminophenyl)-2,3-dihydro-1,3 Aromatic diamines such as 3-trimethyl-1H-indene-5-amine, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, N,N'-bis(4-aminophenyl)terephthalamide, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, and 9,9-bis(4-aminophenyl)fluorene; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine.

[0219] The structural unit B2 may contain one or more structural units other than structural units (B21) and (B22).

[0220] [Method for manufacturing copolymer 2]

[0221] The copolymer 2 can be manufactured by reacting a tetracarboxylic acid component containing a compound providing structural unit A2i and a compound providing structural unit A2a with a diamine component containing a compound providing structural unit B2i and a compound providing structural unit B2a, preferably by a method having steps 1 and 2 described below.

[0222] Step 1: A step in which a compound providing structural unit A2i reacts with a compound providing structural unit B2i to obtain an oligomer having repeating imide structural units.

[0223] Step 2: The process of reacting the oligomer obtained in Step 1 with a compound providing structural unit B2a and optionally a compound providing structural unit A2a to obtain copolymer 2 having imide repeating structural units and amide repeating structural units.

[0224] By means of manufacturing methods having the aforementioned steps 1 and 2, copolymer 2 can be manufactured that can form a film with excellent colorless transparency, heat resistance, low retardation effect, and low residual stress.

[0225] The manufacturing method of copolymer 2 will be described below.

[0226] <Tetracarboxylic acid component>

[0227] The compounds providing structural unit A2i and the compounds providing structural unit A2a preferably contain compounds providing structural unit (A21).

[0228] Examples of compounds providing the structural unit (A21) include compounds shown in formula (a211), formula (a212), formula (a213), and formula (a214), namely tetracarboxylic dianhydrides, but not limited thereto; derivatives thereof may be provided within the range of providing the same structural unit. Examples of such derivatives include tetracarboxylic acids and alkyl esters of the tetracarboxylic acids corresponding to each tetracarboxylic dianhydride. Tetracarboxylic dianhydrides are preferred as compounds providing the structural unit (A21).

[0229] The tetracarboxylic acid component preferably comprises 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more of a compound providing structural unit (A21). The upper limit of this ratio is not particularly limited, but is 100 mol% or less. The compound providing structural unit (A21) need only include at least one compound selected from compounds providing structural unit (A211) to structural unit (A214), and may consist solely of any one compound selected from compounds providing structural unit (A211) to structural unit (A214).

[0230] <Diamine component>

[0231] The compound providing structural unit B2i preferably includes a compound providing structural unit (B21).

[0232] Diamines can be listed as compounds providing the structural unit (B21), but are not limited thereto; derivatives thereof can be used within the range of compounds providing the same structural unit. Diisocyanates corresponding to diamines can be listed as such derivatives. Diamines are preferred as compounds providing the structural unit (B21).

[0233] The diamine component of the raw material serving as the repeating structural unit of the imide preferably comprises 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more of a compound providing the structural unit (B21). There is no particular upper limit to this ratio, but it is 100 mol% or less. The diamine component of the raw material serving as the repeating structural unit of the imide may consist solely of a compound providing the structural unit (B21).

[0234] The compound providing structural unit B2a preferably includes a compound providing structural unit (B22).

[0235] Diamines can be listed as compounds providing the structural unit (B22), but are not limited thereto; derivatives thereof can be used within the range of compounds providing the same structural unit. Diisocyanates corresponding to diamines can be listed as such derivatives. Diamines are preferred as compounds providing the structural unit (B22).

[0236] The diamine component that serves as the raw material for the repeating structural unit of the amide acid preferably comprises 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more of a compound that provides the structural unit (B22). There is no particular upper limit to this ratio, but it is 100 mol% or less. The diamine component that serves as the raw material for the repeating structural unit of the imide may consist solely of a compound that provides the structural unit (B22).

[0237] The ratio of the compound providing the structural unit (B22) in the amine component is preferably 1 to 10 mol%, more preferably 2 to 5 mol%.

[0238] Regarding the ratio of tetracarboxylic acid component to diamine component used in manufacturing copolymer 2, the ratio of diamine component to tetracarboxylic acid component is preferably 0.9 to 1.1 moles per mole of tetracarboxylic acid component.

[0239] It should be noted that in step 1, by using an excessive amount of either the tetracarboxylic acid component or the diamine component, the ends of the resulting oligomer can be converted into carboxylic acid or amine.

[0240] Solvent

[0241] The solvent used to manufacture copolymer 2 need only be able to dissolve the resulting copolymer. Specific examples of reaction solvents are explained for polyimide resin 1. Among the above-mentioned reaction solvents, amide-based solvents or lactone-based solvents are preferred, more preferably amide-based solvents, and even more preferably N-methyl-2-pyrrolidone. The above-mentioned reaction solvents can be used alone or in combination of two or more.

[0242] <Process 1>

[0243] Step 1 is a step in which a compound providing structural unit A2i reacts with a compound providing structural unit B2i to obtain an oligomer having an imide repeating structural unit.

[0244] As the tetracarboxylic acid component used in step 1, it preferably contains a compound that provides the structural unit (A21), and as the diamine component used in step 1, it preferably contains a compound that provides the structural unit (B21).

[0245] Regarding the ratio of the components used in step 1, the tetracarboxylic acid component used in step 1 is preferably 0.9 to 1.1 mol, more preferably 1.0 to 1.1 mol, relative to the diamine component.

[0246] The method for reacting the tetracarboxylic acid component with the diamine component to obtain the oligomer in step 1 is not particularly limited, and known methods can be used. As a specific reaction method, it is explained for polyimide resin 1.

[0247] In the above imidization reaction, known imidization catalysts can be used. As a specific example of an imidization catalyst, as described with respect to polyimide resin 1, the preferred range is also the same.

[0248] From the viewpoint of suppressing reaction rate and gelation, the temperature of the imidization reaction is preferably 120–250°C, more preferably 160–200°C. Furthermore, the reaction time is preferably 0.5–10 hours after the initial distillation of water.

[0249] The oligomer obtained in step 1 contains repeating imide structural units having structural units A2i and B2i.

[0250] The oligomer obtained in step 1 preferably has carboxyl groups at both ends of the main chain of the molecular chain. The carboxyl groups mentioned herein also include derivatives.

[0251] The above method yields a solution containing oligomers dissolved in a solvent. The solution containing the oligomers obtained in step 1 may, without impairing the effects of the present invention, contain at least a portion of the components used in step 1 as tetracarboxylic acid components and diamine components in the form of unreacted monomers.

[0252] <Process 2>

[0253] Step 2 is a step in which the oligomer obtained in step 1 is reacted with a compound providing structural unit B2a and optionally a compound providing structural unit A2a to obtain copolymer 2 having imide repeating structural units and amide repeating structural units.

[0254] The diamine component used in step 2 preferably comprises a compound that provides the structural unit (B22). Alternatively, unreacted diamine components remaining in the solution containing the oligomers obtained in step 1 can be used as the diamine component in step 2.

[0255] In step 2, the tetracarboxylic acid component is arbitrary, but preferably includes a compound that provides the structural unit (A21). Alternatively, unreacted tetracarboxylic acid components remaining in the solution containing the oligomer obtained in step 1 can be used as the diamine component in step 2.

[0256] It should be noted that in step 1, when the two ends of the main chain of the oligomer have carboxyl groups, step 2 can use only the diamine component.

[0257] The method for reacting the oligomer obtained in step 1 with the compound providing structural unit B2a and optionally the compound providing structural unit A2a to obtain the copolymer in step 2 is not particularly limited, and known methods can be used.

[0258] Specific reaction methods include: (1) adding the oligomer, diamine component, tetracarboxylic acid component and solvent obtained in step 1 into a reactor and stirring at 0 to 120°C, preferably at 5 to 80°C, for 1 to 72 hours.

[0259] When the reaction is carried out at a temperature below 80°C, the molecular weight of the copolymer obtained in step 2 does not change due to the temperature process during polymerization, and the thermal imidization process can also be suppressed. Therefore, the copolymer can be manufactured stably.

[0260] Copolymer 2 is a copolymer having repeating ammonium acid structural units and repeating imide structural units. This copolymer is the product of the addition polymerization reaction of the oligomer obtained in step 1 with the diamine component and optionally the tetracarboxylic acid component in step 2.

[0261] The copolymer 2 has an imide repeating structural unit formed in step 1 by the compound providing structural unit A2i and the compound providing structural unit B2i, and has an amide acid repeating structural unit formed in step 2 by the compound providing structural unit B2a and optionally the compound providing structural unit A2a.

[0262] The copolymer solution containing copolymer 2 dissolved in the solvent is obtained by the above method.

[0263] The concentration of the copolymer in the resulting copolymer solution is typically 1 to 50% by mass, preferably 3 to 35% by mass, and more preferably 10 to 30% by mass.

[0264] From the viewpoint of the mechanical strength of the resulting polyimide film, the number-average molecular weight of copolymer 2 is preferably 5,000 to 500,000. It should be noted that the number-average molecular weight of copolymer 2 can be determined, for example, based on a standard polymethyl methacrylate (PMMA) conversion value determined by gel filtration chromatography.

[0265] <Metallic films, semiconductor films, and insulating films>

[0266] The laminate of the present invention preferably has at least one selected from the group consisting of a metal film, a semiconductor film, and an insulating film further laminated on the polyimide film; more preferably, at least one selected from the group consisting of a metal film and a semiconductor film is further laminated on the polyimide film; even more preferably, a semiconductor film is further laminated on the polyimide film; even more preferably, an insulating film and a semiconductor film are further laminated on the polyimide film; and still more preferably, an insulating film and a semiconductor film are sequentially further laminated on the polyimide film. By laminating a metal film or a semiconductor film on the polyimide film, electronic devices (conductive films) targeting contact sensors, OLEDs, etc., can be fabricated on the polyimide film.

[0267] Furthermore, the laminate of the present invention may have an insulating film between the polyimide film and the metal film or semiconductor film, preferably an insulating film. As the insulating film, a SiO2 film is preferred, which functions as a buffer film during the formation of the metal film or semiconductor film.

[0268] Preferred examples of metal films include copper plating and silver plating.

[0269] Preferred examples of semiconductor films include at least one selected from the group consisting of indium tin oxide (ITO), amorphous silicon, indium gallium zinc oxide (IGZO), and low-temperature polycrystalline silicon (LTPS).

[0270] Other metal or semiconductor films can be further stacked on these metal or semiconductor films.

[0271] The thickness of the metal film or semiconductor film is not particularly limited, but is preferably 1 to 400 nm, more preferably 10 to 300 nm, and even more preferably 20 to 200 nm.

[0272] <Conductive Thin Films>

[0273] The conductive thin film of the present invention is obtained by peeling off a glass substrate from the aforementioned laminate. Specifically, it is obtained by peeling off a glass substrate from a laminate on which at least one of a metal film, a semiconductor film, and an insulating film is further laminated. To impart conductivity, a laminate containing either a metal film or a semiconductor film is used as the aforementioned laminate.

[0274] A conductive film can be obtained by immediately peeling off a glass substrate after laminating at least one of a metal film, a semiconductor film, and an insulating film onto a polyimide film, or by storing the laminated film and peeling off the glass substrate as needed. Storing the laminated film improves the maneuverability of the conductive film during transportation and is therefore preferred.

[0275] There is no particular limitation on the method for peeling and removing the glass substrate from the laminate. The laminate of the present invention can easily and stably peel the polyimide film from the glass substrate, thus enabling stable peeling without the use of a release layer. In addition, mechanical peeling is possible without laser irradiation.

[0276] The conductive film obtained by this operation can be used for transparent electrodes, and the laminate of the present invention is preferably used as a laminate for forming transparent electrodes.

[0277] [Manufacturing method of laminated bodies]

[0278] The manufacturing method of the laminate of the present invention is not particularly limited as long as it is a method that can produce a laminate. In other words, the laminate is a laminate in which a polyimide film is tightly bonded on a glass substrate, and the surface free energy of the surface of the glass substrate in contact with the polyimide film is 65 mJ / m. 2 Hereinafter, the proportional limit of the aforementioned polyimide film is 10 to 45 MPa. The preferred manufacturing method is the following method.

[0279] That is, in the manufacturing method of the suitable laminate of the present invention, at least one of polyimide varnish, polyamic acid varnish, and varnish formed by dissolving a copolymer having imide repeating structural units and amic acid repeating structural units in an organic solvent is coated on a glass substrate, and dried to form a polyimide film. In the manufacturing method of the laminate, before coating the aforementioned varnish, there is at least one step selected from a glass substrate alkaline cleaning step and a glass substrate ozone treatment step, and there is a step of adjusting the pressure so that the ratio limit of the obtained polyimide film is 10 to 45 MPa.

[0280] In the manufacturing method of the laminate of the present invention, the surface free energy of the surface of the glass substrate in contact with the polyimide film is made to be 65 mJ / m. 2 Preferably, before applying the polyimide varnish, there is at least one step selected from the glass substrate alkaline cleaning step and the glass substrate ozone treatment step; more preferably, there are both steps, the glass substrate alkaline cleaning step and the glass substrate ozone treatment step; and even more preferably, there are two steps in sequence.

[0281] It should be noted that, before cleaning, if the surface free energy of the contact surface is 65 mJ / m 2 In the following cases, this step is unnecessary. Since the surface free energy of the contact surface varies depending on the location, this step is preferable to eliminate these variations and ensure a uniform surface free energy across the entire contact surface. Furthermore, when using multiple glass substrates, this step is preferable to ensure that all glass substrates meet the aforementioned range.

[0282] The type of glass used in this manufacturing method is as described above and is not particularly limited. Alkali-free glass (borosilicate glass), alkali glass, sodium glass, non-fluorescent glass, phosphate glass, borate glass, quartz, etc. can be used.

[0283] In this process, firstly, it is preferable to have a process that uses alkali to clean the glass substrate, namely, the glass substrate alkali cleaning process.

[0284] Potassium hydroxide is preferred as the alkali used.

[0285] Regarding the cleaning method, it is preferable to immerse the glass substrate in an alkaline aqueous solution, clean it with water, and then dry it.

[0286] The preferred alkali concentration in the alkaline aqueous solution is 0.1% to 1% by mass.

[0287] Preferably, the cleaning is carried out at 20–30°C, and more preferably at 23–25°C.

[0288] Next, it is preferable to have a glass substrate ozone treatment process as an ozone treatment.

[0289] Ozone treatment is performed by irradiating the surface of a glass substrate with ultraviolet light.

[0290] As for irradiation conditions, the cumulative irradiation dose is preferably 150–250 mJ / cm². 2 More preferably, it is 190–200 mJ / cm². 2 .

[0291] In addition, it is preferable to include a process in which the pressure of the resulting polyimide film is adjusted to a ratio limit of 10 to 45 MPa.

[0292] It should be noted that if the polyimide film obtained by directly coating a solution of polyimide resin or polyamic acid as a precursor, or a copolymer having repeating imide and repeating amic acid structural units onto a glass substrate and drying it is within the aforementioned proportional limit range, then this step is not required.

[0293] As described above, there is no limitation on the method of setting the proportional limit of the polyimide film, which is essentially composed of only polyimide resin, to 10 to 45 MPa. This can be done by adjusting the monomer composition, molecular weight, etc. of the polyimide resin. By using the method of including the aforementioned structural unit (B22) in the structural unit of the polyimide resin, the proportional limit of the polyimide film can be easily adjusted to the aforementioned range, which is therefore preferred.

[0294] The preferred step in this process, in which the polyimide film is adjusted to a ratio limit of 10 to 45 MPa, is the addition of resin additives to the aforementioned varnish.

[0295] That is, in this process, it is preferable to add a resin additive to at least one type of varnish selected from polyimide varnish, polyamic acid varnish, and varnish made by dissolving a copolymer having repeating imide structural units and repeating amic acid structural units in an organic solvent.

[0296] Preferred resin additives include phosphate ester compounds, amino-modified silicone oils, organosilicon-containing polymers, acrylic polymers, and fluoropolymers.

[0297] More preferably, it is selected from at least one of the group consisting of phosphate ester compounds, amino-modified silicone oils, and polymers containing organosilicon. From the viewpoint of reducing the peel strength of the laminate, it is preferable to use two or more resin additives in combination, more preferably to use a combination of phosphate ester compounds and polymers containing organosilicon, and even more preferably to use a combination of phosphate ester compounds, amino-modified silicone oils, and polymers containing organosilicon.

[0298] As a phosphate ester compound, it is preferably an acidic phosphate ester compound, and more preferably dibutyl phosphate.

[0299] By including additives, the proportion limit can be reduced, and the proportion limit can be set to the aforementioned range.

[0300] The content of the additive is preferably 0.01 to 0.7% by mass relative to the polyimide resin, polyamic acid varnish, or copolymer having repeating imide and repeating amic acid structural units contained in the varnish, more preferably 0.05 to 0.5% by mass, and even more preferably 0.05 to 0.2% by mass.

[0301] Especially when using phosphate ester compounds, the amount is preferably 0.01 to 0.7% by mass, more preferably 0.01 to 0.3% by mass, and even more preferably 0.01 to 0.1% by mass, relative to the polyimide resin, polyamic acid varnish, or copolymer having repeating imide and repeating amic acid structural units contained in the varnish.

[0302] In addition, when using amino-modified silicone oil, the amount of it is preferably 0.3 to 0.7% by mass, more preferably 0.3 to 0.6% by mass, and even more preferably 0.3 to 0.5% by mass, relative to the polyimide resin, polyamic acid varnish, or copolymer having repeating imide and repeating amic acid structural units contained in the varnish.

[0303] Furthermore, when using a polymer containing organosilicon, the amount of the polymer is preferably 0.05 to 0.7% by mass, more preferably 0.05 to 0.3% by mass, and even more preferably 0.05 to 0.1% by mass, relative to the polyimide resin, polyamic acid varnish, or copolymer having repeating imide and repeating amic acid structural units contained in the varnish.

[0304] In the method for manufacturing the laminate of the present invention, the method for forming the polyimide film is not particularly limited, and known methods can be used. Examples include coating a polyimide varnish, a polyamic acid varnish, or a varnish of a copolymer having repeating imide and repeating amic acid structural units onto a smooth support such as a glass plate, a metal plate, or a plastic, or forming it into a film, and then removing organic solvents such as reaction solvents and diluents contained in the varnish by heating.

[0305] Commonly known coating methods for varnishes include spin coating, slot coating, and plate coating. Among these, slot coating is preferred from the perspectives of controlling intermolecular orientation, improving chemical resistance, and workability.

[0306] As a method for removing organic solvents contained in varnish by heating, it is preferable to evaporate the organic solvent at a temperature below 150°C to make it non-sticky, and then dry it at a temperature above the boiling point of the organic solvent used (not particularly limited, but preferably 200-500°C). Furthermore, drying under an air atmosphere or a nitrogen atmosphere is preferred. The pressure of the drying atmosphere can be any of reduced pressure, atmospheric pressure, or pressurized pressure.

[0307] <Polyimide varnish>

[0308] Polyimide varnish is made by dissolving polyimide resin in an organic solvent. That is, polyimide varnish contains polyimide resin and an organic solvent, wherein the polyimide resin is dissolved in the organic solvent.

[0309] The polyimide resin described above is preferred as the polyimide resin.

[0310] The organic solvent is only required to dissolve the polyimide resin and is not particularly limited. As a reaction solvent for manufacturing polyimide resin, it is preferable to use two or more of the above-mentioned compounds alone or in combination.

[0311] Polyimide varnish can be a polyimide solution obtained by dissolving polyimide resin obtained by polymerization in a reaction solvent, or it can be a substance obtained by further adding a diluting solvent to the polyimide solution.

[0312] By dissolving a solvent-soluble polyimide resin in a solvent, a high-concentration varnish that is stable at room temperature can be prepared. The polyimide varnish preferably contains 5 to 40% by mass of polyimide resin, more preferably 10 to 30% by mass. The viscosity of the polyimide varnish is preferably 1 to 200 Pa·s, more preferably 1.5 to 100 Pa·s, and even more preferably 2 to 100 Pa·s. The viscosity of the polyimide varnish is a value measured using an E-type viscometer at 25°C.

[0313] In addition, polyimide varnishes may contain various additives other than the resin additives mentioned above, such as inorganic fillers, adhesion promoters, flame retardants, UV stabilizers, leveling agents, defoamers, fluorescent whitening agents, crosslinking agents, polymerization initiators, photosensitizers, and adhesion enhancers, without impairing the required properties of the polyimide film.

[0314] There are no particular limitations on the manufacturing method of polyimide varnish; well-known methods can be used.

[0315] <Polyamic acid varnish>

[0316] Alternatively, polyimide films can also be manufactured using polyamic acid varnish, which is made by dissolving polyamic acid in an organic solvent.

[0317] The polyamic acid contained in the aforementioned polyamic acid varnish is a precursor to a polyimide resin. Therefore, it is preferable to use polyamic acid obtained by polymerizing compounds that provide structural units constituting the aforementioned polyimide resin. By imidizing (dehydrating and ring-closing) these polyamic acids, a polyimide resin as the final product is obtained.

[0318] As the organic solvent contained in the aforementioned polyamic acid varnish, the organic solvent contained in the polyimide varnish can be used.

[0319] In this invention, the polyamic acid varnish can be the polyamic acid solution itself obtained by performing an addition polymerization reaction between a tetracarboxylic acid component and a diamine component in a reaction solvent, or the polyamic acid solution can be further diluted with a diluent.

[0320] There are no particular limitations on the method for manufacturing polyimide films using polyamic acid varnish; known methods can be used. For example, a polyamic acid film can be obtained by coating a smooth support such as a glass plate, metal plate, or plastic with a polyamic acid varnish or by forming it into a film, and then removing the organic solvents such as reaction solvents and diluents contained in the varnish by heating. The polyamic acid in the polyamic acid film can then be imidized by heating, thereby manufacturing a polyimide film.

[0321] The preferred heating temperature for drying polyamic acid varnish to obtain a polyamic acid film is 50–120°C. The preferred heating temperature for imidizing polyamic acid by heating is 200–400°C.

[0322] It should be noted that the imidization method is not limited to thermal imidization; chemical imidization can also be used.

[0323] Copolymer varnish

[0324] Alternatively, polyimide films can also be manufactured using copolymer varnishes (hereinafter also referred to as copolymer varnishes) made by dissolving copolymers having repeating imide structural units and repeating ammonium acid structural units in an organic solvent.

[0325] The copolymer varnish is made by dissolving a polyimide resin precursor, namely a copolymer having repeating imide structural units and repeating ammonium acid structural units, in an organic solvent. That is, the copolymer varnish comprises a copolymer and an organic solvent, wherein the copolymer is dissolved in the organic solvent.

[0326] As a copolymer, the copolymer having the aforementioned repeating imide structural unit and repeating ammonium acid structural unit is preferred, and copolymer 2 is more preferred.

[0327] The organic solvent is only required to dissolve the copolymer and is not particularly limited. As a solvent for manufacturing the copolymer, it is preferred to use two or more of the above-mentioned compounds alone or in combination.

[0328] The copolymer varnish can be the copolymer solution itself, or the copolymer solution can be further diluted with a solvent.

[0329] From the viewpoint of efficiently performing imidization of the amic acid sites in copolymers, copolymer varnishes can further contain imidization catalysts and dehydration catalysts. As an imidization catalyst, any imidization catalyst with a boiling point of 40°C or higher and 180°C or lower is acceptable; amine compounds with a boiling point of 180°C or lower are preferred. If an imidization catalyst with a boiling point of 180°C or lower is used, there is no concern about coloring or damage to the appearance of the film during high-temperature drying after film formation. Furthermore, if an imidization catalyst with a boiling point of 40°C or higher is used, the possibility of volatilization before sufficient imidization can be avoided.

[0330] Pyridine or methylpyridine are examples of amine compounds suitable for use as imidization catalysts. These imidization catalysts can be used alone or in combination of two or more.

[0331] Examples of dehydration catalysts include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, trifluoroacetic anhydride, and other acid anhydrides; as well as carbodiimide compounds such as dicyclohexylcarbodiimide. These can be used alone or in combination of two or more.

[0332] The copolymer contained in the copolymer varnish has solvent solubility, thus enabling the production of high-concentration varnishes. The copolymer varnish preferably contains 5-40% by mass of copolymer 2, more preferably 10-30% by mass. The viscosity of the copolymer varnish is preferably 0.1-100 Pa·s, more preferably 0.1-20 Pa·s. The viscosity of the copolymer varnish is a value measured using an E-type viscometer at 25°C.

[0333] In addition, copolymer varnishes may contain various additives other than the resin additives mentioned above, such as inorganic fillers, adhesion promoters, flame retardants, UV stabilizers, leveling agents, defoamers, fluorescent whitening agents, crosslinking agents, polymerization initiators, photosensitizers, and adhesion enhancers, without impairing the required properties of the polyimide film.

[0334] There are no particular restrictions on the manufacturing method of varnish; well-known methods can be used.

[0335] The heating temperature for drying the copolymer varnish to obtain a copolymer film is preferably 50 to 150°C. The heating temperature for imidizing the copolymer by heating can be selected from a range preferably 200 to 500°C, more preferably 250 to 450°C, and even more preferably 300 to 400°C. Furthermore, the heating time is typically 1 minute to 6 hours, preferably 5 minutes to 2 hours, and more preferably 15 minutes to 1 hour.

[0336] Heating atmospheres can include air, nitrogen, oxygen, hydrogen, and nitrogen / hydrogen mixtures. To suppress the coloring of the resulting polyimide resin, nitrogen with an oxygen concentration of less than 100 ppm and nitrogen / hydrogen mixtures with a hydrogen concentration of less than 0.5% are preferred.

[0337] It should be noted that the imidization method is not limited to thermal imidization; chemical imidization can also be used.

[0338] Example

[0339] The present invention will now be described in detail through examples. However, the present invention is not limited to these examples at all.

[0340] In the examples and comparative examples, each property was measured by the methods shown below.

[0341] (1) Thickness of the film

[0342] The thickness of the thin film was measured using a laser microscope (manufactured by Keyence).

[0343] (2) Proportional Limit of Polyimide Film

[0344] A polyimide film was peeled from a 2-layer laminate obtained during the manufacturing process of the 4-layer laminates in the examples and comparative examples. The film was then cut into 10mm × 70mm pieces using a hand cutter to obtain test pieces. It should be noted that in the comparative examples, the test pieces were obtained using portions of the laminate that were partially damaged but still peelable.

[0345] The proportional limit was determined according to JIS K7127:1999 using a tensile testing machine, "STROGRAPH VG-1E," manufactured by Toyo Seiki Co., Ltd. The chuck distance was set to 50 mm, the specimen size to 10 mm × 70 mm, and the testing speed to 20 mm / min. Based on the recorded stress-strain curves, the maximum stress exhibiting a proportional relationship between stress and strain was taken as the proportional limit.

[0346] The proportional limits of the polyimide films obtained by the above operations are shown in Table 2.

[0347] (3) Surface free energy of glass substrate

[0348] The surface free energy of the glass substrates used in the examples and comparative examples was determined by the following operation.

[0349] First, water, ethylene glycol, and diiodomethane were used as probe solutions. Using an automatic contact angle meter (Kyowa Interface Science Co., Ltd., trade name DM300), the contact angle of each liquid on the glass substrate surface at 23°C was determined using the droplet method. The probe solution, glass substrate, and atmosphere within the apparatus were set to 23°C. The contact angle was measured 2 seconds after the probe solution was added.

[0350] Regarding the contact angles of the uncleaned glass substrates (described later), the angles are 35.4° for water, 23.4° for ethylene glycol, and 48.1° for diiodomethane. Regarding the contact angles of the cleaned glass substrates (described later), the angles are 35.4° for water, 29.6° for ethylene glycol, and 55.6° for diiodomethane.

[0351] Substitute the contact angle values ​​of the aforementioned liquids into the following equation (1) to calculate γSd, γSp, and γSh. In equation (1), the values ​​of γLd, γLp, γLh, and γL for each liquid are those described in the following literature (Literature: Proceedings of the 2012 Spring Conference of the China Precision Industry Association, 2012, L69, 975). Next, calculate the surface free energy γS of the solid according to equation (2) and use it as the surface free energy of the glass substrate.

[0352] The surface free energy of the glass substrate obtained by the above operation is shown in Table 2.

[0353] (γSd×γLd) 1 / 2 +(γSp×γLp) 1 / 2 +(γSh×γLh) 1 / 2 =γL(1+cosθ) / 2 (1)

[0354] (In equation (1), γSd represents the dispersion force component of van der Waals forces in the solid, γSp represents the interfacial interaction force of the solid based on polar intermolecular forces (polar component), γSh represents the hydrogen bonding interaction force of the solid (hydrogen bonding component), γLd represents the dispersion force component of van der Waals forces in the liquid, γLp represents the interfacial interaction force of the liquid based on polar intermolecular forces (polar component), γLh represents the hydrogen bonding interaction force of the liquid (hydrogen bonding component), γL represents the surface free energy of the liquid, and θ represents the contact angle of the liquid.)

[0355] γS=γSd+γSp+γSh (2)

[0356] (In equation (2), γS represents the surface free energy of the solid.)

[0357] It should be noted that the aforementioned equation (1) is based on the Young-Dupre formula, the Dupre formula and the extended Fowkes formula.

[0358] (Young-Dupre formula)

[0359] WSL=γL(1+cosθ)

[0360] (In the formula, WSL is the adhesive work, and γL and θ have the same meaning as described above.)

[0361] (Dupre formula)

[0362] γS + γL = WSL + γSL

[0363] (In the formula, γSL is the interfacial free energy, and γS, γL, and WSL have the same meaning as above.)

[0364] (Extended Fowkes formula)

[0365] γSL=γS+γL-{2(γSd×γLd) 1 / 2 +2(γSp×γLp) 1 / 2 +2(γSh×γLh) 1 / 2}

[0366] (In the formula, γSL, γS, γL, γSd, γLd, γSp, γLp, γSh, and γLh have the same meaning as described above.)

[0367] (4) Peelability

[0368] The peelability of the laminate when peeling it from the glass substrate is evaluated according to the following criteria.

[0369] It should be noted that the method for peeling the laminate from the glass substrate is the same as the 90° peel test method used in the evaluation of peel strength described later (5).

[0370] 〇: Capable of peeling the entire laminate from the glass substrate.

[0371] ×: When peeling the laminate from the glass substrate, the strong adhesion between the glass substrate and the laminate may cause partial damage to the laminate.

[0372] (5) Peel strength

[0373] A 90° peel test was performed according to JIS K6854-1 to determine the peel strength between the polyimide film and the glass substrate. The peel strength was measured five times, and the average value was taken as the peel strength.

[0374] The tetracarboxylic acid and diamine components, other components, and their abbreviations used in the manufacturing example are shown below.

[0375] <Tetracarboxylic acid component>

[0376] HPMDA: 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.; compound represented by formula (a11)).

[0377] ODPA: 4,4'-oxydiphthalic anhydride (manufactured by MANAC; compound shown in formula (a12))

[0378] s-BPDA: 3,3',4,4'-Biphenyltetracarboxylic acid dianhydride (Mitsubishi Chemical Corporation, compound shown by formula (a211s))

[0379] <Diamine component>

[0380] 3,3'-DDS: 3,3'-diaminodiphenyl sulfone (manufactured by SEIKA; compound shown in formula (b11))

[0381] HFBAPP: 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (manufactured by SEIKA; compound shown in formula (b121)).

[0382] BAPS: bis[4-(4-aminophenoxy)phenyl]sulfone (manufactured by SEIKA; compound shown in formula (b122))

[0383] 6FODA: 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (prepared by China Tech (Tianjin) Chemical Co., Ltd., compound shown in formula (b21))

[0384] X-22-1660B-3: Two-terminal amino-modified silicone oil (manufactured by Shin-Etsu Chemical Industry Co., Ltd., compound shown in formula (b22) (functional group equivalent: 2200 g / mol or 2170 g / mol))

[0385] <Other>

[0386] GBL: γ-Butyrolactone (manufactured by Mitsubishi Chemical Corporation)

[0387] TEA: Triethylamine (manufactured by Kanto Chemical Co., Ltd.)

[0388] DMAc: N,N-dimethylacetamide (manufactured by Mitsubishi Gas Chemical Company)

[0389] <Manufacturing of Polyimide Varnishes and Copolymer Varnishes>

[0390] Manufacturing Example 1

[0391] 23.530 g (0.094 mol) of 3,3'-DDS, 12.247 g (0.024 mol) of HFBAPP, and 62.820 g of GBL were added to a 300 mL five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a Dean-Stark apparatus with a condenser, a thermometer, and glass end caps. The mixture was stirred at 70 °C under a nitrogen atmosphere at 200 rpm to obtain a solution.

[0392] After adding 24.216 g (0.108 mol) of HPMDA, 3.721 g (0.012 mol) of ODPA, and 15.705 g of GBL to the solution, 0.596 g of TEA was added as an imidization catalyst. The reaction system was heated using a covered heater, and the temperature was raised to 190°C over approximately 20 minutes. The distilled components were collected, and the rotation speed was adjusted according to the viscosity increase. The temperature of the reaction system was maintained at 190°C, and the mixture was refluxed for 5 hours.

[0393] Subsequently, 161.475 g of GBL was added at a solid content of 20% by mass. The temperature of the reaction system was cooled to 100°C and then stirred for about 1 hour to homogenize it, thus obtaining polyimide varnish 1.

[0394] Manufacturing Example 2

[0395] 13.845 g (0.056 mol) of 3,3'-DDS, 24.115 g (0.056 mol) of BAPS, and 41.903 g of GBL were added to a 300 mL five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a Dean-Stark apparatus with a condenser, a thermometer, and glass end caps. The mixture was stirred at 70 °C under a nitrogen atmosphere at 200 rpm to obtain a solution.

[0396] After adding 22.499 g (0.100 mol) of HPMDA, 3.459 g (0.011 mol) of ODPA, and 12.804 g of GBL to the solution, 0.564 g of TEA was added as an imidization catalyst. The reaction system was heated using a covered heater, and the temperature was raised to 190 °C over approximately 20 minutes. The distilled components were collected, and the rotation speed was adjusted according to the viscosity increase. The temperature of the reaction system was maintained at 190 °C, and the mixture was refluxed for approximately 5 hours.

[0397] Subsequently, 175.981 g of GBL was added at a solid content of 20% by mass. The temperature of the reaction system was cooled to 100°C and then stirred for about 1 hour to homogenize it, thus obtaining polyimide varnish 2.

[0398] Manufacturing Example 3

[0399] 21.127 g (0.063 mol) of 6 FODA and 94.051 g of DMAc were added to a 300 mL five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a Dean-Stark apparatus with a condenser, a thermometer, and glass end caps. The mixture was stirred at 25 °C under a nitrogen atmosphere and at 200 rpm to obtain a solution.

[0400] After adding 19.195 g (0.065 mol) of s-BPDA and 23.513 g of DMAc to the solution, the mixture was heated using a covered heater, raising the temperature of the reaction system to 50°C over approximately 20 minutes. The distilled components were collected, and the rotation speed was adjusted according to the viscosity increase. The temperature of the reaction system was maintained at 50°C and refluxed for approximately 5 hours. Subsequently, 139.190 g of DMAc was added, and the temperature of the reaction system was cooled to 25°C, yielding a solution containing oligomers with repeating imide structural units.

[0401] Add to the resulting solution a mixture obtained by dissolving 10.063 g (0.002 mol) of X-22-1660B-3 in 15.466 g of DMAc, and stir further for about 1 hour to obtain copolymer varnish 3 containing a copolymer (PI-b-PAA) with a solid component concentration of about 20% by mass. Here, the copolymer having imide repeating structural units and amide repeating structural units is referred to as "PI-b-PAA".

[0402] The composition of the polyimide resin and copolymer contained in the varnishes obtained in Examples 1 to 3 is shown in Table 1.

[0403] [Table 1]

[0404] Table 1

[0405]

[0406] The additives and glass substrates used in the examples and comparative examples are shown below.

[0407] <Resin Additives>

[0408] Resin Additive 1: Dibutyl phosphate (DBP, Chengbei Chemical Industry Company)

[0409] Resin Additive 2: Amino-modified silicone oil (X-22-9409, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0410] Resin Additive 3: Polymer containing organosilicon (Polyflow KL-700, Kyoei Chemical Co., Ltd.)

[0411] <Other Additives>

[0412] Leveling agent: BYK-378 (BYK-Chemie Japan)

[0413] Adhesion enhancer: BYK-4513 (BYK-Chemie Japan)

[0414] <Glass substrate>

[0415] Unwashed glass substrate: Use alkali-free glass directly (trade name: AN-100, standard: 100mm×100mm×0.7mm, manufactured by AGC).

[0416] Cleaned glass substrate: The aforementioned alkali-free glass AN-100 was cleaned by chemical solution treatment and ozone treatment. In the chemical solution treatment, the glass was immersed in a potassium hydroxide aqueous solution (concentration: 0.1% by mass) at 23°C for 3 minutes, then temporarily removed and rinsed with deionized water. The glass surface was then allowed to dry thoroughly at room temperature (23°C). Next, as an ozone treatment, the glass surface was irradiated with ultraviolet light (cumulative irradiation dose: 190–200 mJ / cm²). 2 The attached substances are then decomposed and removed. The irradiation time is set to 8 seconds.

[0417] <Fabrication of Layered Structures>

[0418] Example 1

[0419] In the polyimide varnish 1 obtained in Manufacturing Example 1, a leveling agent of 0.1% by mass relative to the polyimide resin in the varnish, a resin additive 1 of 0.1% by mass relative to the polyimide resin in the varnish, a resin additive 2 of 0.5% by mass relative to the polyimide resin in the varnish, and a resin additive 3 of 0.1% by mass relative to the polyimide resin in the varnish are mixed and then applied to a cleaned glass substrate by spin coating to obtain a substrate coated with varnish.

[0420] Using a heating plate, the resulting varnish-coated substrate is held at 80°C for 20 minutes, and then heated at 260°C for 30 minutes in an air dryer to evaporate the solvent, resulting in a two-layer laminate (glass / polyimide film).

[0421] Furthermore, a 30 nm thick SiO2 film is formed on the polyimide film of the two-layer stack by sputtering, and an ITO (indium tin oxide) film with a thickness of 120 nm is formed on it to obtain a four-layer stack (glass / polyimide film / SiO2 film / ITO film).

[0422] Comparative Example 1

[0423] After mixing a leveling agent of 0.1% by mass relative to the polyimide resin in the varnish into the polyimide varnish 1 obtained in Manufacturing Example 1, the varnish was applied to a cleaned glass plate by spin coating to obtain a varnish-coated substrate. Otherwise, the obtained varnish-coated substrate was processed in the same way as in Example 1 to obtain a 4-layer laminate (glass / polyimide film / SiO2 film / ITO film).

[0424] Example 2

[0425] After mixing a leveling agent (0.1% by mass relative to the polyimide resin in the varnish), a resin additive 1 (0.1% by mass relative to the polyimide resin in the varnish), and a resin additive 3 (0.1% by mass relative to the polyimide resin in the varnish) into the polyimide varnish 2 obtained in Manufacturing Example 2, the mixture is spin-coated onto a cleaned glass plate to obtain a varnish-coated substrate. Otherwise, the obtained varnish-coated substrate is processed in the same manner as in Example 1 to obtain a four-layer laminate (glass / polyimide film / SiO2 film / ITO film).

[0426] Comparative Example 2

[0427] After mixing a leveling agent of 0.1% by mass relative to the polyimide resin in the varnish into the polyimide varnish 2 obtained in Manufacturing Example 2, the varnish was applied to an uncleaned glass substrate by spin coating to obtain a varnish-coated substrate. Otherwise, the obtained varnish-coated substrate was processed in the same way as in Example 1 to obtain a 4-layer laminate (glass / polyimide film / SiO2 film / ITO film).

[0428] Comparative Example 3

[0429] After mixing a leveling agent of 0.1% by mass relative to the polyimide resin in the varnish into the polyimide varnish 2 obtained in Manufacturing Example 2, the varnish was applied to a cleaned glass plate by spin coating to obtain a varnish-coated substrate. Otherwise, the obtained varnish-coated substrate was processed in the same way as in Example 1 to obtain a 4-layer laminate (glass / polyimide film / SiO2 film / ITO film).

[0430] Example 3

[0431] After mixing a leveling agent of 0.1% by mass relative to the copolymer in the varnish 3 obtained in Manufacturing Example 3, the varnish was applied to a cleaned glass plate by spin coating to obtain a varnish-coated substrate. Otherwise, the obtained varnish-coated substrate was processed in the same way as in Example 1 to obtain a 4-layer laminate (glass / polyimide film / SiO2 film / ITO film).

[0432] Example 4

[0433] After mixing a leveling agent and an adhesion promoter of 0.1% by mass relative to the copolymer in the varnish 3 obtained in Manufacturing Example 3, the mixture was spin-coated onto a cleaned glass plate to obtain a varnish-coated substrate. Otherwise, the obtained varnish-coated substrate was processed in the same manner as in Example 1 to obtain a 4-layer laminate (glass / polyimide film / SiO2 film / ITO film).

[0434] Comparative Example 4

[0435] After mixing a leveling agent of 0.1% by mass relative to the copolymer in the varnish 3 obtained in Manufacturing Example 3, the varnish was applied to an unwashed glass plate by spin coating to obtain a varnish-coated substrate. Otherwise, the varnish-coated substrate was processed in the same manner as in Example 1 to obtain a 4-layer laminate (glass / polyimide film / SiO2 film / ITO film).

[0436] The peelability and peel strength of the obtained laminates were evaluated. The results are shown in Table 2.

[0437] [Table 2]

[0438] Table 2

[0439]

[0440] According to the results in Table 2, the laminate of the embodiment can stably peel off the polyimide film from the glass substrate without using a release layer.

Claims

1. A laminate comprising a polyimide film tightly bonded to a glass substrate, wherein the surface free energy of the surface of the glass substrate in contact with the polyimide film is 65 mJ / m. 2 The following limits for the proportionality of the polyimide film are 10–45 MPa. The polyimide resin of the polyimide film has structural units A1 derived from tetracarboxylic dianhydride and structural units B1 derived from diamine. Structural unit A1 contains structural units (A11) derived from the compound shown in formula (a11), and structural unit B1 contains structural units (B11) derived from the compound shown in formula (b11). The polyimide film comprises polyimide resin and resin additives. The resin additive is selected from at least one of the groups consisting of phosphate ester compounds and organosilicon-containing polymers.

2. The laminated body according to claim 1, wherein, The peel strength of the polyimide film from the glass substrate is below 20 gf / cm.

3. The laminate according to claim 1 or 2, wherein, The thickness of the polyimide film is 3–20 μm.

4. The laminate according to claim 1 or 2, wherein, The structural unit A1 also includes a structural unit (A12) derived from the compound shown in the following formula (a12).

5. The laminate according to claim 1 or 2, wherein, At least one of the group consisting of a metal film, a semiconductor film, and an insulating film is further stacked on the polyimide film.

6. The laminate according to claim 5, wherein, The semiconductor film is selected from at least one of the group consisting of indium tin oxide, amorphous silicon, indium gallium zinc oxide, and low-temperature polycrystalline silicon.

7. The laminate according to claim 1 or 2, wherein, The organosilicon-containing polymers include amino-modified silicone oils.

8. A method for manufacturing a laminated body, wherein, A polyimide film is formed by coating a glass substrate with at least one varnish selected from the group consisting of polyimide varnish, polyamic acid varnish, and varnishes formed by dissolving copolymers having repeating imide structural units and repeating amic acid structural units in an organic solvent, and then drying the varnish. The method for manufacturing the laminate includes at least one step selected from a glass substrate alkaline cleaning step and a glass substrate ozone treatment step before applying the varnish, and includes a step of adjusting the pressure so that the resulting polyimide film has a proportional limit of 10 to 45 MPa. The process of adjusting the pressure so that the resulting polyimide film has a proportional limit of 10 to 45 MPa is the process of adding resin additives to the varnish. The resin additive is selected from at least one of the groups consisting of phosphate ester compounds and organosilicon-containing polymers. The polyimide resin of the polyimide film has structural units A1 derived from tetracarboxylic dianhydride and structural units B1 derived from diamine. Structural unit A1 contains structural units (A11) derived from the compound shown in formula (a11), and structural unit B1 contains structural units (B11) derived from the compound shown in formula (b11). The surface free energy of the surface of the glass substrate in contact with the polyimide film is 65 mJ / m. 2 the following, 9. The manufacturing method according to claim 8, wherein, The organosilicon-containing polymers include amino-modified silicone oils.

10. A conductive thin film obtained by peeling off the glass substrate from the laminate of claim 5 or 6.

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