JP2018130837A - Multilayer film roll, and method for producing the multilayer film roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laminated plate obtained by temporarily fixing a polymer film base material for obtaining a satisfactory flexible electronic device.SOLUTION: A multilayer film obtained by successively winding a polymer film base material layer having a width exceeding 500 mm and a thickness of 12 to 190 μm, a polyimide precursor layer having a thickness of 5 to 200 μm and a thickness variation of 20% or lower, including an organic solvent in a ratio of 20 to 35 mass%, and, preferably, having a reduction viscosity of 0.5 to 5.0 dL/g and a separator film layer having a thickness of 5 to 130 μm around a columnar winding core in a length of 50 m or higher to obtain a multilayer film roll. From the multilayer film roll, a polyimide precursor film is pulled out and is laminated on a glass or the like to obtain a laminated plate.SELECTED DRAWING: None

Description

  In the present invention, a flexible polyimide film is temporarily fixed to a rigid temporary supporting inorganic substrate as a laminate, and then various electronic devices or functional thin films are formed on the polyimide film, and then the polyimide film is converted into an electronic device portion, or The present invention relates to a manufacturing technique for peeling a functional thin film together to obtain a flexible electronic device or a functional thin film, the laminate, and a polyimide precursor roll for obtaining the laminate.

  Functional elements (devices) such as semiconductor elements, MEMS elements, and display elements are used as electronic components in information communication equipment (broadcast equipment, mobile radio, portable communication equipment, etc.), radar, high-speed information processing devices, etc. Conventionally, it is generally formed or mounted on an inorganic substrate such as glass, a silicon wafer, or a ceramic substrate. However, in recent years, attempts have been made to form various functional elements on a polymer film substrate in light of the demand for lighter, smaller, thinner, and more flexible electronic components.

  Furthermore, in recent years, there has been an increasing interest in transparent polymer film substrates used in place of conventional glass substrates used in highly functional mobile phones and display devices.

  In forming various functional elements on the surface of the polymer film, it is ideal to process by a so-called roll-to-roll process using the flexibility that is a characteristic of the polymer film. However, in the industries such as the semiconductor industry, the MEMS industry, and the display industry, a process technology for a rigid flat substrate such as a wafer base or a glass substrate base has been mainstream. Therefore, in order to form various functional elements on the surface of the polymer film using the existing infrastructure, the polymer film is bonded to a rigid support made of an inorganic material (glass plate, ceramic plate, silicon wafer, metal plate, etc.). A process has been devised in which a desired element is formed and then peeled off from the support.

  In general, a relatively high temperature is often used in the step of forming a functional element. For example, a temperature range of about 200 to 500 ° C. is used in forming a functional element such as polysilicon or an oxide semiconductor. In manufacturing a low-temperature polysilicon thin film transistor, heating at about 450 ° C. may be required for dehydrogenation. Also in the production of a hydrogenated amorphous silicon thin film, a temperature range of about 200 to 300 ° C. is required. The temperature range exemplified here is not so high for inorganic materials, but it can be said that it is considerably high for polymer films and adhesives generally used for laminating polymer films. I don't get it. Adhering the above-mentioned polymer film to an inorganic substrate and peeling off after forming the functional element, the polymer film used, the adhesive used for bonding, and the adhesive also require sufficient heat resistance. As a matter of fact, however, there are limited polymer films that can withstand practical use in such a high temperature range. In addition, conventional adhesives and pressure-sensitive adhesives have not been obtained with sufficient heat resistance.

Generally, since a heat-resistant adhesive means for temporarily attaching a polymer film to an inorganic substrate cannot be obtained, in such applications, a polymer film solution or a precursor solution is applied onto the inorganic substrate and then dried on the inorganic substrate. A technique called a varnish method or a coat-debond method, which is cured and formed into a film and used for the application, is known.
For example, Patent Document 1 discloses a method for manufacturing a flexible active matrix layer in which a polyimide layer is applied to a glass substrate and then cured by heat treatment, a thin film active element is formed thereon, and then peeled off from the glass substrate. It is disclosed. However, the polymer film obtained by such means is difficult to obtain a thick film due to the restriction that the precursor solution must be applied to a limited area, and has a large film thickness unevenness from the center to the end. It is extremely difficult to obtain a film having a sufficient thickness. Moreover, since the film obtained by this method is brittle and easily torn, the functional element is often destroyed when peeling from the inorganic substrate. In particular, it is extremely difficult to peel off a device having a large area, and it is not possible to obtain a yield that can be industrially established.
In view of such circumstances, the present inventors, as a laminate of a polymer film and a support for forming a functional element, use a polyimide film that has excellent heat resistance and is strong and can be made into a thin film as a coupling agent. The laminated body formed by sticking together to the support body (inorganic layer) which consists of an inorganic substance through was proposed (patent documents 2-4). If the laminated body described in these patent documents 2-4 is used, it will become possible to bond a polymer film and an inorganic substrate, without using what is called an adhesive and an adhesive element, and also the laminated body is a thin film. Exfoliation of the polymer film does not occur even when exposed to the high temperatures required to fabricate the device. Therefore, it is possible to produce an electronic device on a polymer film by subjecting the laminate to a process for forming an electronic device directly on an inorganic substrate such as a conventional glass plate or silicon wafer. A flexible electronic device can be realized by peeling the molecular film from the inorganic substrate.

However, this technique still has the following problems in industrial production.
In particular, when manufacturing a high-definition electronic device, yield is an issue. When foreign matter is mixed between the polymer film and the inorganic substrate, a tent-like structure in which the foreign matter is regarded as a support is formed on and around the foreign matter. This creates voids between the polymer film and the inorganic substrate, resulting in locations that are not partially bonded. Since the gas confined in the gap tends to swell in a heating environment or a reduced pressure environment, it causes a swell defect (also called blistering). Further, since the void portion is not bonded, when the bonding strength is macroscopically grasped, the variation in the bonding strength becomes large.
In the vicinity where foreign matter exists, the polymer film itself is in a raised state, which becomes an obstructive factor in pattern formation using photolithographs and high-definition patterns such as microcontact printing, and good electronic device formation There is a case that cannot be performed.

  Such foreign matter can be reduced by cleaning the surface of the inorganic substrate and the surface of the polymer film and cleaning the work environment. However, work in a high clean environment requires a large amount of equipment, and there are significant restrictions on the entry and exit of workers and the loading of materials. If the device has a relatively small area, such as an electronic circuit element, the size of the processing apparatus can be reduced, and even if a defect occurs, it can be used while avoiding the defect part, which is practically sufficient. It can be expected that the yield will be very low in the case of a large area device such as a display.

  In order to solve the above problems, the present inventors have solved the shortcomings of the varnish method and the technique of directly attaching a film, and have heat resistance and flexibility on an inorganic substrate, and are useful as a base material for flexible electronic devices. Have proposed a polyimide precursor film layer / inorganic substrate laminate that makes it possible to form a simple polyimide film layer without any defects (Patent Documents 5 and 6).

JP 2001-356370 A JP 2010-283262 A JP 2011-11455 A JP 2011-245675 A Japanese Patent Laying-Open No. 2015-202675 JP2015-202675A

  Since the polyimide precursor film described in Patent Documents 5 and 6 described above is flexible and can be appropriately plastically deformed, even when foreign matter is interposed between the polyimide precursor film and the inorganic substrate, Although it is possible to produce a laminated intermediate so as not to be a defect, problems remain regarding winding of the flexible polyimide precursor film itself, handling and scratches during unwinding, protection from foreign matters, etc. Met.

  As a result of diligent studies to solve the above problems, the present inventors have improved the handleability of the polyimide precursor film, and have heat resistance and flexibility on the inorganic substrate, and the flexible electronic device or the functional thin film. The inventors have reached the invention of a polyimide precursor roll that makes it possible to form a polyimide film layer useful as a substrate without any defects.

That is, the present invention has the following configuration.
[1] A multilayer film roll in which a multilayer film having a width exceeding 500 mm and a length of 50 m or more is wound in a roll shape on a cylindrical core,
The multilayer film is
A polymer film substrate layer having a thickness of 12 μm or more and 190 μm or less,
A polyimide precursor layer having a thickness of 5 μm or more and 200 μm or less, a thickness spot of 20% or less, and an organic solvent in a proportion of 20% by mass or more and 35% by mass or less;
A separator film layer having a thickness of 5 μm or more and 130 μm or less,
A multilayer film roll characterized by having a structure in which the layers are sequentially laminated.
[2] The multilayer film roll according to [1], wherein the reduced viscosity of the polyimide precursor is 0.5 dL / g or more and 5.0 dL / g or less.
[3] The multilayer film roll according to [1] or [2], wherein an absolute value of a thickness unevenness of the polymer film substrate layer is 10 μm or less.
[4] The multilayer film roll according to any one of [1] to [3], wherein an absolute value of a thickness unevenness of the separator film layer is 10 μm or less.
[5] The roundness of the inner diameter of the cylindrical core is 99.87% or more, and the roundness of the outer diameter is 99.87% or more [1] to [4] A multilayer film roll according to any one of the above.
[6] A winding core having an inner diameter roundness of 99.87% or more and an outer diameter roundness of 99.87% or more is used with a winding core mounted so that the eccentricity is 200 μm or less. ,
An organic solvent solution of a polyimide precursor is applied to a polymer film substrate having a thickness of 12 μm or more and 190 μm or less and an absolute value of the thickness unevenness of 10 μm or less. Dry so as to be in the range of 20% by mass or more and 35% by mass or less with respect to the total amount of the solvent,
Further, the separator film having a thickness of 5 μm or more and 130 μm or less and an absolute value of the thickness unevenness of 10 μm or less is wound on the layer containing the polyimide precursor and the solvent. [5] A method for producing the multilayer film roll according to any one of [5].

Further, the present invention preferably has the following configuration.
[7] A layer containing a polyimide precursor unwound from the multilayer film roll according to any one of [1] to [5] is laminated on an inorganic substrate that has been organically treated in advance to obtain a polyimide precursor film layer / A method for obtaining an inorganic substrate laminate.
[8] A method of obtaining a polyimide film / inorganic substrate laminate by heat-treating the polyimide precursor film layer / inorganic substrate laminate obtained by the method according to [7] to convert the polyimide precursor film into a polyimide film. .
[9] A method of obtaining a functionalized polyimide film layer / inorganic substrate laminate by forming a functional thin film or an electronic device on the polyimide film surface of the polyimide film / inorganic substrate laminate obtained by the method according to [8].
[10] A method for producing a functionalized polyimide film, wherein the functionalized polyimide film layer is peeled off from the functionalized polyimide film layer / inorganic substrate laminate obtained by the method according to [9].
[11] As described in [1] to [5], the light transmittance at 400 nm of the polyimide film is 70% or more, the HAZE is 1.5% or less, and the yellowness is 5.0 or less by heat treatment. A multilayer film roll according to [6] to [10].

  As described above, the polyimide precursor film is flexible and can be appropriately plastically deformed. Therefore, even when a foreign substance is interposed between the polyimide precursor film and the inorganic substrate, there is no disadvantage. Thus, although it is possible to produce a laminated intermediate as described above, due to its flexibility, problems remain in winding up the polyimide precursor film, handling properties during unwinding, scratches, and protection from foreign matter.

  According to the present invention, a polyimide precursor film roll protected from scratches, foreign matters, and the like can be obtained by winding up a polyimide precursor film formed on a polymer film substrate together with a separator film. Furthermore, by using the polyimide precursor film, it is possible to obtain a good quality polyimide precursor film layer / inorganic substrate laminate and a functionalized polyimide film layer / inorganic substrate laminate with few scratches and foreign matters on the surface. Become. The flexible electronic device or functional thin film obtained by peeling from the functionalized polyimide film layer / inorganic substrate laminate is suitable for electronic devices and optical devices such as various displays, and the polyimide film layer is transparent. In addition, it can be used for a see-through display or the like.

The polyimide precursor film roll of the present invention comprises a polyimide precursor film layer / polymer film substrate laminate comprising a polymer film substrate and a polyimide precursor film formed on the surface thereof, and a separator film layer.

The polyimide precursor film in the present invention means a film layer made of a polyimide precursor in a state that is approximately semi-solid and capable of elastic deformation and plastic deformation to some extent. Such a film layer often contains an organic solvent, but in the present invention, for convenience, a layer containing a polyimide precursor and an organic solvent is referred to as a polyimide precursor film or a polyimide precursor film layer. The polyimide precursor film layer of the present invention may be in any state such as a high-viscosity liquid, or a very soft solid, or a solid-liquid composite called a slurry, gel, sol, etc. And having a self-supporting property that can be wound together with the separator film.
The polyimide precursor includes a physical precursor such as a high concentration solution of polyimide that becomes a polyimide film layer by drying and solidifying. The precursor also includes a chemical precursor such as polyamic acid which becomes a final polyimide through the remaining one to several chemical reactions.

  The reduced viscosity of the polyimide precursor in the present invention is preferably 0.5 dL / g or more and 5.0 dL / g or less, more preferably 0.8 dL / g or more and 4.2 dL / g or less, and still more. More preferably, it is 1.2 dL / g or more and 3.8 dL / g or less. When the reduced viscosity exceeds a predetermined range, the viscosity of the precursor solution becomes too high, and an overload occurs during liquid feeding or coating. On the other hand, if the reduced viscosity is less than the predetermined range, the toughness of the final film obtained may be reduced.

  The polyimide resin for forming the polyimide film layer in the present invention is not particularly limited as long as it is a polyimide resin that can form a film in a precursor state. Polyamideimide, polyetherimide, polyesterimide, aromatic polyimide, alicyclic polyimide, fluorinated polyimide, and the like can be used.

  In addition to the polymer precursor as the main component, a solvent, a gelling agent, a thickener, a filler, and the like can be appropriately blended in the polyimide precursor film layer of the present invention as necessary.

  The thickness of the polyimide precursor film layer of the present invention is 5 μm or more, preferably 11 μm or more, and more preferably 19 μm or more. The upper limit of the thickness of the polyimide precursor film layer is not particularly limited, but is preferably 200 μm or less, more preferably 180 μm or less, and even more preferably 160 μm or less because of the demand as a flexible electronic device.

  The polyimide precursor film layer of the present invention preferably contains 20 wt% or more, more preferably 22 wt% or more of an organic solvent capable of dissolving the polyimide precursor. When the organic solvent content is less than 20 wt%, the adhesion between the polyimide precursor film layer and the polymer film as the substrate is increased, making it difficult to easily peel off. The upper limit of the organic solvent content of the polyimide precursor film is preferably 35 wt% or less, more preferably 33 wt% or less, and even more preferably 30 wt% or less. When the organic solvent content exceeds 35 wt%, the self-supporting property of the polyimide precursor film is lowered, and thus handling becomes difficult.

The organic solvent contained in the polyimide precursor film layer is not particularly specified as long as it is an organic solvent capable of dissolving the polyimide precursor. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, NN- Dimethylformamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone, cyclopentanone, and the like can be used. These may be used alone or in combination of two or more. Considering productivity and optical properties of the film, it is preferable to use N-methyl-2-pyrrolidone or N, N-dimethylacetamide as the main component of the organic solvent. In addition to these organic solvents, a poor solvent such as toluene or xylene may be used to such an extent that the polyimide resin or its precursor does not precipitate.

The present invention is a multilayer film roll having a width exceeding 500 mm on a cylindrical winding core.
The present invention is a multilayer film roll in which a multilayer film having a length of 50 m or more is wound into a roll.
The present invention provides a polymer film substrate layer having a thickness of 12 μm or more and 190 μm or less,
A polyimide precursor layer having a thickness of 5 μm or more and 200 μm or less, a thickness spot of 20% or less, and an organic solvent in a proportion of 20% by mass or more and 35% by mass or less;
A separator film layer having a thickness of 5 μm or more and 130 μm or less,
Is a multilayer film roll having a structure in which are sequentially laminated.

In the present invention, the cylindrical winding core is made of paper, thermoplastic resin, thermosetting resin, fiber reinforced plastic, metal, or the like. In the present invention, a core made of resin or metal is preferable, and a core made of ABS resin or glass fiber reinforced plastic is preferable. The roundness of the inner diameter of the core of the present invention is preferably 99.87% or more, and more preferably 99.94% or more. In addition, the winding core of the present invention preferably has an outer diameter roundness of 99.87% or more, and more preferably 99.94% or more. Here, the roundness is defined by the following equation for the major axis and minor axis of the cylinder measured at an arbitrary position of the cylinder.
Roundness = 100 × minor axis / major axis

  Furthermore, in the present invention, a winding core having an inner diameter roundness of 99.87% or more and an outer diameter roundness of 99.87% or more is mounted on a winder so that the eccentricity is 200 μm or less. It is desirable to use it.

The thickness unevenness of the polyimide precursor film layer in the present invention is 20% or less, preferably 12% or less, more preferably 6% or less, and particularly preferably 3% or less. In addition, the film thickness unevenness is determined by, for example, extracting the position of about 10 points or more, preferably 30 points from the film to be measured with a contact-type film thickness meter, and measuring the film thickness. Can be sought.
Film thickness spots (%)
= 100 × (maximum film thickness−minimum film thickness) ÷ average film thickness

  The thickness unevenness of the polyimide precursor film layer is substantially reflected in the thickness unevenness of the polyimide film. A polyimide film is a substrate material for a flexible electronic device, and dominates the mechanical characteristics of the electronic device itself, so that the thickness unevenness corresponds to the unevenness of mechanical properties. For the manufacture of electronic devices, a coating method, a printing method, a photolithographic method, or the like is used in combination. Since the unevenness of the thickness of the film substrate, which is the substrate, is reflected as irregularities on the surface of the substrate, the pattern may not be transferred to the recess when the contact printing method is used. This phenomenon is relatively small in screen printing, but it becomes a problem when using lithographic printing with contact transfer, lithographic offset printing, gravure printing, gravure offset printing, letterpress printing, microcontact printing, reverse printing, etc. There are many. In addition, when using the photolithographic method, the film thickness unevenness is reflected in the distance unevenness between the exposure mask and the exposed portion, and therefore, the defocusing of the projected image and the edge blur are likely to occur. Especially in the formation of fine lines and small dots, there will be a great hindrance.

  The polyimide film particularly preferably used in the present invention is a colorless transparent polyimide film, and aromatic polyimide, alicyclic polyimide, polyamideimide, polyesterimide, polyetherimide and the like can be used. However, this is not particularly the case when a back element of a reflective or self-luminous display is formed.

In general, a transparent polyimide film is obtained by applying a polyamic acid (polyimide precursor) solution obtained by reacting diamines and tetracarboxylic acids in a solvent to a polymer film substrate and drying it to obtain a green film ("precursor film"). Or a “polyamic acid film”), and further, a green film is subjected to a high temperature heat treatment on a support for forming a polyimide film or in a state of being peeled from the support to cause a dehydration ring-closing reaction. Also, a polyimide solution obtained by reacting diamines and tetracarboxylic acids in a solvent and then proceeding an imidization reaction in a solvent with a chemical imidizing agent, or a polyimide containing a chemical imidizing agent A polyimide solution obtained by re-dissolving a polyimide purified by a method such as reprecipitation from a solution is again applied to a polymer film substrate and dried to form a green film (also referred to as a “precursor film”). It can be obtained by solidifying and drying the green film on a support for film production or in a state peeled off from the support.
In the present invention, these green films are handled as polyimide precursor films.

The diamine component used for the synthesis of the polyimide resin of the present invention or a precursor thereof is not particularly limited, and aromatic diamines, aliphatic diamines, alicyclic diamines, etc. that are usually used for transparent polyimide synthesis may be used. it can. Examples of diamine compounds include 1,3-phenylenediamine, 1,4-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,4-diaminotoluene, 4,5-dimethyl-1,2 -Phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,6-dimethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3- Aminobenzylamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2,2'-dimethylbiphenyl-4,4'-diamine, 2,2'-bis (trifluoromethyl) benzidine 3,3'-dimethoxybenzidine, 4,4'-diaminooctafluorobiphenyl, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-methylenebis ( 2,6-diethylaniline), 4,4'-methylenebis (2-ethyl-6-methyla) Phosphorus), 4,4'-ethylenedianiline, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2,2'-bis (trifluoromethyl) -4, 4'-diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (4-Amino-2-trifluoromethylphenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-diamino-3,3'-dimethyldiphenylmethane, bis [4- (4- Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis (3-aminophenyl) hexafluoropropane 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-bis [4- (4-Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, α, α'-bis (4-aminophenyl) -1,4 -Diisopropylbenzene, bis (2-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 4 , 4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzanilide, 1,4-bis (4-aminobenzoyloxy) benzene, 1,4-bis (4-aminophenoxy) benzene And aromatic diamines such as bis (4-aminophenyl) terephthalate, 2,7-diaminofluorene, and 9,9-bis (4-aminophenyl) fluorene. Aliphatic diamines include 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis (aminomethyl) cyclohexane, 1,1-bis (4-aminophenyl) cyclohexane, 4,4'-diaminodicyclohexyl Methane, 4,4'-methylenebis (2-methylcyclohexylamine), 4,4'-methylenebis (2,6-dimethylcyclohexylamine), 4,4'-diaminodicyclohexylpropane, bicyclo [2.2.1] heptane-2 , 3-diamine, bicyclo [2.2.1] heptane-2,5-diamine, bicyclo [2.2.1] heptane-2,6-diamine, bicyclo [2.2.1] heptane-2,7-diamine, 2,3 -Bis (aminomethyl) -bicyclo [2.2.1] heptane, 2,5-bis (aminomethyl) -bicyclo [2.2.1] heptane, 2,6-bis (aminomethyl) -bicyclo [2.2.1] heptane 3 (4), 8 (9) -bis (aminomethyl) tricyclo [5.2.1.0 (2,6)] decane and the like. Of these, p-phenylenediamine, 2,2'-dimethylbiphenyl-4,4'-diamine, 2,2'-bis (trifluoromethyl) benzidine, 2,2'-bis (trifluoro) are particularly preferred. Methyl) -4,4'-diaminodiphenyl ether, 1,4-bis (4-amino-2-trifluoromethylphenoxy) benzene, 1,4-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4 ' -Methylenebis (2-methylcyclohexylamine), 4,4'-methylenebis (2,6-dimethylcyclohexylamine). The said amine component may be used independently and may use 2 or more types together.

  The tetracarboxylic acids constituting the polyamic acid include aromatic tetracarboxylic acids (including their acid anhydrides), aliphatic tetracarboxylic acids (including their acid anhydrides), and alicyclic tetratetrahydrocarbons commonly used for transparent polyimide synthesis. Carboxylic acids (including their acid anhydrides) can be used. Among these, aromatic tetracarboxylic anhydrides and alicyclic tetracarboxylic anhydrides are preferable, and alicyclic tetracarboxylic acids are more preferable from the viewpoint of light transmittance. In the case where these are acid anhydrides, the number of anhydride structures in the molecule may be one or two, but those having two anhydride structures (dianhydrides) are preferred. Good. Tetracarboxylic acids may be used alone or in combination of two or more.

  Examples of the alicyclic tetracarboxylic acids include alicyclic tetracarboxylic acids such as cyclobutanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, and 3,3 ′, 4,4′-bicyclohexyltetracarboxylic acid. Carboxylic acids and their acid anhydrides are mentioned. Among these, dianhydrides having two anhydride structures (for example, cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3 ′, 4,4 '-Bicyclohexyltetracarboxylic dianhydride and the like) are preferred. In addition, alicyclic tetracarboxylic acids may be used independently and may use 2 or more types together.

  The aromatic tetracarboxylic acids are not particularly limited, but are preferably pyromellitic acid residues (that is, those having a structure derived from pyromellitic acid), and more preferably acid anhydrides thereof. Examples of such aromatic tetracarboxylic acids include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 3 , 3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride, 2,2-bis [4- (3,4-di Carboxyphenoxy) phenyl] propanoic anhydride and the like. In addition, aromatic tetracarboxylic acids may be used independently and may use 2 or more types together.

The transparent polyimide film of the present invention preferably has a transmittance at 400 nm of 70% or more. Furthermore, 80% or more is more preferable. HAZE is preferably 1.5% or less, and more preferably 1.0% or less. The yellowness is preferably 5.0 or less, and more preferably 4.0 or less. When the optical characteristics satisfy the above range, for example, high display characteristics are exhibited in a substrate application, and therefore, it can be suitably used for the above application. In addition, the said measured value is a value measured by the measuring method shown in an Example.

As the support for preparing a polyimide precursor film (polymer film substrate layer) in the present invention, an extremely general resin film can be used. As a resin film as a base material, polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, wholly aromatic polyester, other copolymer polyester, polycarbonate, polyamide, polysulfone, polyethersulfone, polyetherketone, Polyamideimide, polyetherimide, aromatic polyimide, alicyclic polyimide, fluorinated polyimide, cellulose acetate, cellulose nitrate, aromatic polyamide, polystyrene, etc., using a resin film obtained by melt stretching or solution casting Can do. The resin film as a preferable coating substrate in the present invention is a polyethylene terephthalate film, a polyethylene naphthalate film, or a polyimide film, and particularly preferably a polyethylene terephthalate film.
The polyimide precursor film preparation support in the present invention, that is, the polymer film substrate layer, preferably has a thickness of 12 μm or more and 190 μm or less, and an absolute value of thickness spots of 10 μm or less, and further has a thickness. It is preferable that it is 45 micrometers or more and 130 micrometers or less, and the absolute value of a thickness spot is 6 micrometers or less.

As the separator film in the present invention, an extremely general resin film can be used. Resin films include polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, wholly aromatic polyester, other copolyesters, polycarbonate, polyamide, polysulfone, polyethersulfone, polyetherketone, polyamideimide, poly Etherimide, aromatic polyimide, alicyclic polyimide, fluorinated polyimide, cellulose acetate, cellulose nitrate, aromatic polyamide, polystyrene, and the like can be used as a resin film obtained by a melt stretching method or a solution film forming method. The resin film as a preferable separator film in the present invention is a polyethylene film, a polypropylene film, a polyethylene terephthalate film, polybutylene terephthalate, or polyethylene naphthalate. From the viewpoint of cost, a polyethylene film, a polypropylene film, and a polyethylene terephthalate film are particularly preferable.
Such a separator film is wound together with the polymer film substrate on which the polyimide precursor film is formed to form the separator film layer of the present invention. The separator film layer of the present invention preferably has a thickness of 5 μm or more and 130 μm or less and an absolute value of thickness spots of 10 μm or less, and further has a thickness of 18 μm or more and 80 μm or less of absolute values of thickness spots. Is preferably 7 μm or less, more preferably 24 μm or more and 56 μm or less, and the absolute value of the thickness unevenness is preferably 5 μm or less.

  In the present invention, a polyimide precursor film layer is formed on such a substrate. The polyimide precursor film layer is formed by applying a solvent solution of a polyimide precursor to a substrate and making it into a semi-solid state by drying or semi-curing treatment, gelling treatment, or the like. In this invention, it dries so that content of an organic solvent may become the range of 20 mass% or more and 35 mass% or less with respect to the sum total of a polyimide precursor and an organic solvent. Application methods include dip coating, spray coating, spin coating, curtain coating, slit die coating, comma coating, reverse coating, applicator method, bar coating, screen printing, gravure coating, etc. A method may be used. In the present invention, it is particularly preferable to use a curtain coating method, a slit die coating method, or a comma coating method. By using such a coating method, the uneven thickness of the film thickness, which is an essential requirement of the present invention, can be reduced. Preferably, in the present invention, it is necessary to obtain the polyimide precursor film layer in a continuous long form. The multilayer film roll of the present invention is obtained by winding the long polyimide precursor film / polymer film substrate laminate together with the separator film.

In this invention, the roll and winding of a polyimide precursor film using the said separator film can reduce the damage | wound and adhesion of a foreign material to the polyimide precursor film surface in each handling process.
In the present invention, scratches and foreign matters are collectively regarded as a defect. Microscope observations with a size of 5 μm or more were regarded as defects, and the number in a 30 mm × 30 mm region was measured.

  The polyimide precursor film layer / inorganic substrate laminate of the present invention comprises at least an inorganic substrate and a polyimide precursor film layer.

  The inorganic substrate in the present invention may be a plate-like substrate that can be used as a substrate made of an inorganic material, for example, a glass plate, a ceramic plate, a semiconductor wafer, a metal wafer or the like mainly, and these glass plates, Examples of the ceramic plate, silicon wafer, and metal composite include those obtained by laminating them, those in which they are dispersed, and those containing these fibers.

  Examples of the glass plate include quartz glass, high silicate glass (96% silica), soda lime glass, lead glass, aluminoborosilicate glass, borosilicate glass (Pyrex (registered trademark)), borosilicate glass (non-alkali), Borosilicate glass (microsheet), aluminosilicate glass and the like are included. Among these, those having a linear expansion coefficient of 5 ppm / K or less are desirable, and if it is a commercial product, “Corning (registered trademark) 7059” or “Corning (registered trademark) 1737” manufactured by Corning, which is a glass for liquid crystal, “EAGLE”, “AN100” manufactured by Asahi Glass, “OA10” manufactured by Nippon Electric Glass, “AF32” manufactured by SCHOTT, etc. are desirable.

  Ceramic plates include Al2O3, Mullite, AlN, SiC, Si3N4, BN, crystallized glass, Cordierite, Spodumene, Pb-BSG + CaZrO3 + Al2O3, Crystallized glass + Al2O3, Crystallized Ca-BSG, SG Ceramics for substrates such as ceramic, zero-dur, TiO2, strontium titanate, calcium titanate, magnesium titanate, alumina, MgO, steatite, BaTi4O9, BaTiO3, BaTi4 + CaZrO3, BaSrCaZrTiO3, Ba (TiZr) O3, PMN-PT, Capacities such as PFN-PFW Data material, PbNb2O6, Pb0.5Be0.5Nb2O6, PbTiO3, BaTiO3, PZT, 0.855PZT-95PT-0.5BT, 0.873PZT-0.97PT-0.3BT, include piezoelectric materials such as PLZT is.

  As a semiconductor wafer, a silicon wafer, a semiconductor wafer, a compound semiconductor wafer, or the like can be used. A silicon wafer is a product obtained by processing single crystal or polycrystalline silicon on a thin plate, and doped n-type or p-type. In addition to silicon wafers, silicon wafers including silicon oxide layers and various thin films deposited on the surface of silicon wafers are also included. In addition to silicon wafers, germanium and silicon-germanium are also included. Gallium-arsenic, aluminum-gallium-indium, nitrogen-phosphorus-arsenic-antimony, SiC, InP (indium phosphorus), InGaAs, GaInNAs, LT, LN, ZnO (zinc oxide), CdTe (cadmium tellurium), ZnSe (selenium) Semiconductor wafers, compound semiconductors, etc. A body wafer or the like can be used.

  Metals include single element metals such as W, Mo, Pt, Fe, Ni, Au, Ag, Ti, Al, Cu, Inconel, Monel, Nimonic, Carbon copper, Silicon steel, Brass, Bronze, White bronze, White, Alloys such as nickel silver, Fe-Ni invar alloy, super invar alloy, and stainless steel are included. In addition, a multilayer metal plate formed by adding other metal layers and ceramic layers to these metals is also included. In this case, if the total CTE with the additional layer is low, Cu, Al or the like is also used for the main metal layer. The metal used as the additional metal layer is limited as long as it has strong adhesion to the polyimide film, no diffusion, and good chemical resistance and heat resistance. Although it is not, chromium, nickel, TiN, and Mo containing Cu are mentioned as a suitable example.

It is desirable that the planar portion of the inorganic substrate is sufficiently flat. Specifically, the PV value of the surface roughness is 50 nm or less, more preferably 20 nm or less, and further preferably 5 nm or less. If it is rougher than this, the adhesive strength between the polymer film and the inorganic substrate may be insufficient.
The thickness of the inorganic substrate is not particularly limited, but is preferably 10 mm or less, more preferably 3 mm or less, and still more preferably 1.3 mm or less from the viewpoint of handleability. The thickness is not particularly limited, but 0.07 mm or more, preferably 0.15 mm or more, and more preferably 0.3 mm or more is preferably used.

The area of the inorganic substrate is preferably a large area from the viewpoint of production efficiency and cost of the laminate and the flexible electronic device. It is preferably 1730 cm ² or more, more preferably 4300Cm ² or more, further not less 6700Cm ² or more, and yet still preferably 13000Cm ² or more.

  In the present invention, a polyimide precursor film layer / inorganic substrate laminate is obtained by transferring a polyimide precursor film unwound from a polyimide precursor film roll from a polymer film substrate to an inorganic substrate.

As for the transfer method of such a polyimide precursor film, several methods can be exemplified as shown below. However, these exemplifications are not intended to limit the present invention, and the transfer may be carried out by a technique that is considered to be optimal as appropriate in accordance with the specific characteristics of the polyimide precursor film, inorganic substrate, etc., and the convenience of the process.
(1) A method of peeling a polymer film substrate after the polyimide precursor film is attached to an inorganic substrate together with the polymer film substrate.
(2) A method in which a polyimide precursor film is peeled off from a polymer film substrate and directly attached to an inorganic substrate.
(3) A method in which a polyimide precursor film is transferred from a polymer film substrate to another carrier material, and then the polyimide precursor film is attached to an inorganic substrate together with the carrier material, and the carrier material is peeled off.

  In the present invention, a silane coupling agent can be used to organically treat the inorganic base material. The silane coupling agent is preferably applied and reacted in advance on the surface of the inorganic substrate (silane coupling agent treatment). In the present invention, the organic treatment of the inorganic substrate in advance means mainly this silane coupling agent treatment.

<Silane coupling agent>
The silane coupling agent in the present invention refers to a compound that is physically or chemically interposed between the inorganic substrate and the polyimide film layer and has an action of increasing the adhesive force between the two.
Preferable specific examples of the silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- ( Aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, vinyltrichlorosilane, Vinyltrimethoxysilane, vinyltriethoxysila 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryl Trimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltriethoxysilane, 3-chloropropyl Limethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane, tris- (3-trimethoxysilylpropyl) isocyanurate Chloromethylphenethyltrimethoxysilane, chloromethyltrimethoxysilane, aminophenyltrimethoxysilane, aminophenethyltrimethoxysilane, aminophenylaminomethylphenethyltrimethoxysilane, hexamethyldisilazane and the like.

n-propyltrimethoxysilane, butyltrichlorosilane, 2-cyanoethyltriethoxysilane, cyclohexyltrichlorosilane, decyltrichlorosilane, diacetoxydimethylsilane, diethoxydimethylsilane, dimethoxydimethylsilane, dimethoxydiphenylsilane, dimethoxymethylphenylsilane, dodecyl Lichlorosilane, dodecyltrimethoxysilane, ethyltrichlorosilane, hexyltrimethoxysilane, octadecyltriethoxysilane, octadecyltrimethoxysilane, n-octyltrichlorosilane, n-octyltriethoxysilane, n-octyltrimethoxysilane, triethoxyethyl Silane, triethoxymethylsilane, trimethoxymethylsilane, trimethoxyphenylsilane, pentyltri Toxisilane, pentyltrichlorosilane, triacetoxymethylsilane, trichlorohexylsilane, trichloromethylsilane, trichlorooctadecylsilane, trichloropropylsilane, trichlorotetradecylsilane, trimethoxypropylsilane, allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane , Diethoxymethylvinylsilane, dimethoxymethylvinylsilane, trichlorovinylsilane, triethoxyvinylsilane, vinyltris (2-methoxyethoxy) silane, trichloro-2-cyanoethylsilane, diethoxy (3-glycidyloxypropyl) methylsilane, 3-glycidyloxypropyl (dimethoxy) ) Methylsilane, 3-glycidyloxypropyltrimethoxysilane, etc. It is also possible to use.

Among such silane coupling agents, the silane coupling agent preferably used in the present invention is preferably a silane coupling agent having a chemical structure having one silicon atom per molecule of the coupling agent.
In the present invention, particularly preferred silane coupling agents include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2. -(Aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, aminophenyl Trimethoxysilane, aminophenethyltrimethoxysilane Emissions, such as aminophenyl aminomethyl phenethyltrimethoxysilane the like. In the case where particularly high heat resistance is required in the process, it is desirable to use an aromatic group between Si and an amino group.
In the present invention, if necessary, a phosphorus coupling agent, a titanate coupling agent, or the like may be used in combination.

<Application method of silane coupling agent>
As a coating method of the silane coupling agent in the present invention, a liquid phase coating method or a gas phase coating method can be used.
As a coating method in a liquid phase, using a solution obtained by diluting a silane coupling agent with a solvent such as alcohol, a spin coating method, a curtain coating method, a dip coating method, a slit die coating method, a gravure coating method, a bar coating method, Common liquid coating methods such as a comma coating method, an applicator method, a screen printing method, and a spray coating method can be exemplified. In the case of using a coating method in a liquid phase, it is preferable to dry quickly after coating, and to perform a heat treatment at about 100 ± 30 ° C. for about several tens of seconds to 10 minutes. By the heat treatment, the silane coupling agent and the surface of the coated surface are bonded by a chemical reaction.

In the present invention, the silane coupling agent can be applied by a vapor phase method. The application by the vapor phase method is by exposing the substrate to the vapor of the silane coupling agent, that is, the silane coupling agent in a substantially gaseous state. The vapor of the silane coupling agent can be obtained by heating the silane coupling agent in a liquid state to a temperature from 40 ° C. to about the boiling point of the silane coupling agent. Although the boiling point of a silane coupling agent changes with chemical structures, it is the range of about 100-250 degreeC in general. However, heating at 250 ° C. or higher is not preferable because it may cause decomposition or side reaction on the organic group side of the silane coupling agent.
The environment for heating the silane coupling agent may be under pressure, at about normal pressure, or under reduced pressure, but is preferably at about normal pressure or under reduced pressure in order to promote vaporization of the silane coupling agent. Since many silane coupling agents are flammable liquids, it is preferable to perform the vaporizing operation in an airtight container, preferably after replacing the inside of the container with an inert gas.
The time for exposing the inorganic substrate to the silane coupling agent is not particularly limited, but is within 20 hours, preferably within 60 minutes, more preferably within 15 minutes, and even more preferably within 1 minute.
The inorganic substrate temperature during exposure of the inorganic substrate to the silane coupling agent is controlled to an appropriate temperature between −50 ° C. and 200 ° C. depending on the type of silane coupling agent and the desired thickness of the silane coupling agent layer. It is preferable.
The inorganic substrate exposed to the silane coupling agent is preferably heated to 70 ° C. to 200 ° C., more preferably 75 ° C. to 150 ° C. after the exposure. By such heating, the hydroxyl group on the surface of the inorganic substrate reacts with the alkoxy group or silazane group of the silane coupling agent, and the silane coupling agent treatment is completed. The time required for heating is about 10 seconds to 10 minutes. When the temperature is too high or when the time is too long, the coupling agent may be deteriorated. If it is too short, the treatment effect cannot be obtained. If the substrate temperature being exposed to the silane coupling agent is already 80 ° C. or higher, the subsequent heating can be omitted.
In the present invention, it is preferable to expose the inorganic substrate to the silane coupling agent vapor while holding the silane coupling agent application surface of the inorganic substrate downward. In the liquid phase coating method, the coating surface of the inorganic substrate is inevitably facing upward during and before coating, and therefore it is impossible to deny the possibility that floating foreign substances or the like in the working environment are deposited on the surface of the inorganic substrate. However, the coating method using the gas phase can hold the inorganic substrate downward. It is possible to greatly reduce the adhesion of foreign substances in the environment.
Cleaning the surface of the inorganic substrate before the silane coupling agent treatment by means such as short wavelength UV / ozone irradiation or cleaning with a liquid cleaning agent is a significant preferable operation.

With respect to the coating amount and thickness of the coupling agent, a single molecular layer is theoretically sufficient, and a thickness that can be ignored in terms of mechanical design is sufficient. Generally, it is less than 400 nm (less than 0.4 μm), preferably 200 nm or less (0.2 μm or less), more practically 100 nm or less (0.1 μm or less), more preferably 50 nm or less, still more preferably 10 nm or less. However, when the calculation is in the region of 5 nm or less, it is assumed that the coupling agent is present not in the form of a uniform coating but in a cluster shape, which is not preferable.
The film thickness of the coupling agent layer is obtained by ellipsometry or by calculating from the concentration and application amount of the coupling agent solution at the time of application, or by converting from the amount of elements unique to the silane coupling agent by surface element analysis Etc. can be used.

<Patterning treatment of inorganic substrate>
In the present invention, patterning treatment can be performed on the inorganic substrate side. Here, patterning refers to creating a region where the coating amount or activity of the coupling agent is intentionally manipulated. Thereby, in a laminated body, it has a favorable adhesion part and easy peeling part from which the peeling strength between an inorganic substrate and a polyimide film differs, and this favorable adhesion part and this easy peeling part can form a predetermined pattern. . An example of the patterning treatment is a method of manipulating the coating amount of the silane coupling agent using a mask prepared in advance with a predetermined pattern when applying the silane coupling agent. It is also possible to perform patterning by irradiating the surface to which the silane coupling agent is applied with active energy rays and using a technique such as masking or scanning operation at the same time. Here, active energy ray irradiation is an operation of irradiating energy rays such as ultraviolet rays, electron rays, and X-rays, and ozone gas generated in the vicinity of the irradiation surface simultaneously with the ultraviolet ray irradiation light effect as in the case of ultraviolet ray irradiation treatment with an extremely short wavelength. Include gas exposure effects. In addition to these, patterning can be performed by corona treatment, vacuum plasma treatment, atmospheric pressure plasma treatment, sandblasting and treatment, or the like.

  The good adhesion part in this invention points out the part with the strong adhesive strength of an inorganic substrate and a polyimide film, and the easily peelable part in this invention points out the part with the weak adhesive strength of an inorganic substrate and a polyimide film. The adhesive strength of the easily peelable portion is preferably 1/2 or less, more preferably 1/3 or less, and further preferably 1/4 or less of the adhesive strength of the good adhesive portion. Although the lower limit value of the adhesive strength is not particularly limited, it is preferably 0.5 N / cm or more at the good adhesion portion and 0.01 N / cm or more at the easy peel portion.

  By heating the polyimide precursor film layer / inorganic substrate laminate of the present invention, a polyimide film layer / inorganic substrate laminate can be obtained. When the polyimide precursor film is a polyamic acid film, the heat treatment is preferably carried out at a temperature of 350 ° C. or lower and the dehydration ring-closing reaction is preferably carried out at 320 ° C. or lower. When processing at a temperature exceeding 350 ° C., it is difficult to suppress coloring of the polyimide film. When the polyimide precursor film is a film made of soluble polyimide, it is preferable to solidify and dry at a temperature of 300 ° C. or lower, and it is preferable to process at 250 ° C. or lower.

When a polyimide film layer / inorganic substrate laminate is obtained from the polyimide precursor film layer / inorganic substrate laminate of the present invention by heat treatment and used as a substrate for electronic device formation or functional thin film formation, an existing electronic device is obtained. Or, an electronic device or a functional thin film is formed on a polyimide film layer of a laminate using a facility or process for producing a functional thin film, and the functionalized polyimide film is peeled off from the laminate to provide a flexible electronic device or function. Can be produced.
The electronic device or functional thin film in the present invention is an electronic circuit including an active element such as a wiring board, a transistor, and a diode, and a passive device such as a resistor, a capacitor, and an inductor, pressure, temperature, light, etc. Sensor elements that sense humidity, light emitting elements, liquid crystal displays, electrophoretic displays, self-luminous display and other image display elements, wireless and wired communication elements, arithmetic elements, memory elements, MEMS elements, solar cells, thin film transistors, etc. .
As a method of peeling the functionalized polyimide film from the laminate, a method in which strong light is irradiated from the inorganic substrate side and the adhesive part between the inorganic substrate and the polyimide film is thermally decomposed or photodecomposed and peeled off is used. Examples of weakening and peeling the polyimide film with a force less than the elastic strength limit value of the polyimide film, exposing to heated water, heated steam, etc., weakening the bond strength between the inorganic substrate and the polyimide film interface, etc. I can do it.

  In the present invention, when the patterning treatment is performed on the inorganic substrate side or the polyimide film layer side, or both, the region where the adhesive force between the polyimide film layer and the inorganic substrate is reduced by the patterning treatment (easy peeling part) The electronic device or functional thin film is formed on the outer periphery of the region, and then the area on which the polyimide film electronic device or functional thin film is formed is peeled off from the inorganic substrate. A device or a functional thin film can be obtained. By this method, the polyimide film and the inorganic substrate can be more easily separated.

  As a method of cutting the polyimide film layer along the outer periphery of the easily peelable portion of the laminate, a method of cutting the polyimide film with a cutting tool such as a blade, or a polyimide film by relatively scanning the laser and the laminate A method of cutting a polyimide film by relatively scanning a water jet and a laminate, a method of cutting a polyimide film while cutting a glass layer slightly with a semiconductor chip dicing apparatus, and the like can be used. In addition, a combination of these methods, a method of superimposing ultrasonic waves on a cutting tool, or adding a reciprocating operation or an up / down operation to improve cutting performance can be appropriately employed.

  When making a cut in the polyimide film layer on the outer periphery of the easy-release part of the laminate, the position where the cut is made only needs to include at least a part of the easy-release part, and basically may be cut according to a predetermined pattern. From the viewpoint of error absorption, productivity, etc., it may be determined as appropriate.

The method of peeling the functionalized polyimide film layer from the support is not particularly limited, but is a method of tapping from the end with tweezers or the like, and after attaching an adhesive tape to one side of the cut portion of the functionalized polyimide film layer, the tape A method of turning from the part, a method of turning from one side of the cut portion of the functionalized polyimide film after vacuum suction, and the like can be employed. In addition, when the bend with a small curvature occurs in the cut portion of the functionalized polyimide film at the time of peeling, stress is applied to the device in that portion and the device may be destroyed. It is desirable. For example, it is desirable to roll while winding on a roll having a large curvature, or to roll using a machine having a configuration in which the roll having a large curvature is located at the peeling portion.
In addition, a method in which another reinforcing base material is attached in advance to the part to be peeled and the whole reinforcing base material is peeled off is also useful. When the functionalized polyimide film layer to be peeled off is a backplane of a display device, a display device front plane is pasted in advance and integrated on an inorganic substrate, and then both are peeled off simultaneously to obtain a flexible display device. Is possible.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited by a following example. In addition, the evaluation method of the physical property in the following examples is as follows.

<Reduced viscosity of polyamic acid solution>
A solution dissolved in N, N-dimethylacetamide so that the polymer concentration was 0.2 g / dl was measured at 30 ° C. using an Ubbelohde type viscosity tube.

<Thickness of polyimide precursor film layer>
The thickness of the polyimide precursor film layer was measured using a micrometer (“Millitron 1245D” manufactured by Fine Reef).

<Thickness unevenness of polyimide precursor film>
Thirty points of the thickness of the polyimide precursor film were randomly measured by a predetermined method, the average value, the maximum value, the minimum value, and the standard deviation were obtained, and the thickness unevenness was obtained from the following formula.
Film thickness variation (%) = 100 × (maximum film thickness−minimum film thickness) ÷ average film thickness

<Content of organic solvent in polyimide precursor film>
The organic solvent content was measured using TGA 2950 (TA instruments). About 5 mg of sample was set in an Al microcell and heated to 500 ° C. at a rate of 5 ° C./min. The measurement was performed in a nitrogen atmosphere, and the weight reduced between 100 ° C. and 300 ° C. was defined as the organic solvent content.

<Number of defects>
A 30 mm × 30 mm area was sampled from the polyimide film layer / inorganic substrate laminate, and the sampling area was observed with a microscope with a length measurement function of 100 × magnification. The major axis length was measured at 400 times, and the number of those having a diameter of 5 μm or more was taken as a factor. Sampling was performed from three locations in each sample, and the average number of defects was taken.

<Light transmittance>
The light transmittance at a wavelength of 400 nm was measured using a spectrophotometer U-3210 manufactured by Hitachi, Ltd.

<HAZE>
The HAZE of the film was measured using a Nippon Denshoku HAZE meter NDH2000 and a CIE standard D65 light source. In addition, the same measurement was performed 3 times and the arithmetic average value was adopted.

<Yellowness (YI)>
The yellowness of the film was measured using a color difference meter ZE2000 manufactured by Nippon Denshoku Co., Ltd., using a CIE standard C2 light source. In addition, the same measurement was performed 3 times and the arithmetic average value was adopted.

(Synthesis Example 1)
After the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, the reaction vessel was charged with 205.8 g of 1,4-bis (4-amino-2-trifluoromethylphenoxy) benzene in a nitrogen atmosphere ( 0.480 mol) and 1200 g of N, N-dimethylacetamide were dissolved, and 93.8 g (0.478 mol) of cyclobutanetetracarboxylic dianhydride was added in portions while cooling the reaction vessel. For 12 hours. The solution was diluted with 1000 g of N, N-dimethylacetamide to obtain a polyamic acid solution A1 having a reduced viscosity of 4.12 dl / g.

(Synthesis Example 2)
The inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then the reaction vessel was filled with 176.5 g of 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl (0. 551 mol) and 1200 g of N, N-dimethylacetamide were dissolved, and 122.9 g (0.548 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride was added to the solid while cooling the reaction vessel. The solution was added in portions and stirred at room temperature for 18 hours. Thereafter, it was diluted with 500 g of N, N-dimethylacetamide to obtain a polyamic acid solution A2 having a reduced viscosity of 2.98 dl / g.

(Synthesis Example 3)
The inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then the reaction vessel was filled with 155.9 g (0.735 mol) of 2,2′-dimethyl-4,4′-diaminobiphenyl in a nitrogen atmosphere. And 1,200 g of N, N-dimethylacetamide were dissolved in the solution, and 142.9 g (0.729 mol) of cyclobutanetetracarboxylic dianhydride was added in portions while cooling the reaction vessel, followed by stirring at room temperature for 5 hours. did. Thereafter, it was diluted with 1000 g of N, N-dimethylacetamide to obtain a polyamic acid solution A3 having a reduced viscosity of 4.39 dl / g.

(Synthesis Example 4)
The inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then the reaction vessel was charged with 78.3 g (0.724 mol) of phenylenediamine and 1200 g of N, N-dimethylacetamide in a nitrogen atmosphere and dissolved. Then, while cooling the reaction vessel, 220.6 g (0.720 mol) of 3,3 ′, 4,4′-bicyclohexyltetracarboxylic dianhydride was added in portions while being solid, and stirred at room temperature for 15 hours. . Thereafter, the mixture was diluted with 250 g of N, N-dimethylacetamide to obtain a polyamic acid solution A4 having a reduced viscosity of 3.23 dl / g.

(Synthesis Example 5)
The inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was replaced with nitrogen, and then the reaction vessel was charged with 800 ml of a 50:50 mixed solvent of 400 ml of N, N-dimethylacetamide and 400 ml of ethylene carbonate in a nitrogen atmosphere. 4-Bis (4-aminobenzoyloxy) benzene 72.0 (0.230 mol) and cyclobutanetetracarboxylic dianhydride 50.0 g (0.255 mol) were mixed and stirred at 70 ° C. for 30 minutes, and uniformly transparent Solution was obtained. After the solution was cooled to room temperature, 7.5 g (0.026 mol) of 1,4-bis (4-aminophenoxy) benzene was added and stirred. As a result, the viscosity increased significantly. Stir for 16 hours. A polyamic acid solution A5 having a reduced viscosity of 1.67 dL / g was obtained.

(Synthesis Example 6)
After substituting the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring bar with nitrogen, 41.9 g (0.1 mol) of cyclohexatricarboxylic acid anhydride, dicyclohexylmethane-4,4 ′ in a nitrogen atmosphere in the reaction vessel. -52.3 g (0.1 mol) of diisocyanate and 0.34 g of 1,8-diazabicyclo [5,4,0] -7-undecene were added and dissolved in 107 g of γ-butyrolactone. After reacting at 150 to 200 ° C. for 2 hours, 213 g of N-methyl-2-pyrrolidone was added and stirred at 200 ° C. for 1 hour. A polyamic acid solution A6 having a reduced viscosity of 0.9 dl / g was obtained.

Example 1
Using a slit die, the polyamic acid solution (A1) is applied onto the smooth surface (non-sliding material surface) of a long polyethylene terephthalate film having a thickness of 125 μm (absolute value of thickness spots 4 μm) and a width of 1050 mm. The film was coated so that the film thickness after imidization was 20 μm, dried at 120 ° C. for 15 minutes, and then smoothed as a separator film of a long polyethylene terephthalate film having a thickness of 20 μm (absolute value of thickness spots: 2 μm). The roundness of the inner diameter is 99.90% and the roundness of the outer diameter is 99.90% so that the eccentricity is 150 μm with the surface (non-sliding material surface) superimposed on the polyimide precursor film. Using a 90% winding core, the film was wound into a roll under the condition of a winding tension of 120 N to obtain a polyimide precursor film roll (B1).

(Silane coupling agent coated glass plate)
A heating bat placed in a closed chamber with a ventilation port and an intake port is filled with a silane coupling agent, 3-methacryloxypropylmethyldiethoxysilane (trade name KBM-503, manufactured by Shin-Etsu Silicone), 75 Warmed to ° C. Next, a white plate glass having a square shape of 250 mm on a side is held at 100 mm on a heating bat, the position of the glass plate is shaken in the horizontal direction so that the silane coupling agent vapor is uniformly applied, and the glass plate is taken out after being exposed for 5 minutes. It put on the heated hotplate and heated for 10 minutes, and the silane coupling agent application | coating glass plate was obtained.

  In a laboratory adjusted to room temperature 23 ° C. ± 2 ° C., humidity 50 ± 5% RH, and cleanness 10000, the obtained polyimide precursor film roll B1 was unwound, and the separator film and the base film were all square of 360 mm × 460 mm. Cut into shape. Next, the separator film is peeled off, and the polyimide precursor film side previously cut out is aligned on a white plate glass of 370 mm x 470 mm so that the end of the glass plate coated with the silane coupling agent is exposed 5 mm, manufactured by Climb Products Was laminated at an inorganic substrate temperature of 30 ° C., a roll pressure of 5 kg / cm 2 during lamination, and a roll speed of 5 mm / sec. Subsequently, the base film in contact with the polyimide precursor film was peeled off to obtain a polyimide precursor film layer / inorganic substrate laminate (C1) composed of a glass plate and a polyimide precursor.

  The resulting polyimide precursor film (D1) had an average thickness of 23.0 μm, a maximum of 23.3 μm, a minimum of 22.7 μm, and a thickness variation of 2.61%. The organic solvent content was 25.6 wt%.

  The obtained polyimide precursor film layer / inorganic substrate laminate is put in an explosion-proof oven, first heated to 150 ° C. and held for 5 minutes, and then raised to 220 ° C. at a rate of 10 ° C./minute. Then, the temperature was raised to 300 ° C. at a rate of 10 ° C./min., Held for 5 minutes, and then taken out from the oven to obtain white plate glass and a polyimide film layer / inorganic substrate laminate (E1).

  The laminate (E1) had good appearance quality, and no blisters, protrusions, foreign matters, etc. were observed on the polyimide film surface, and the number of defects was zero. In addition to protecting the polyimide precursor film with the separator film, the laboratory where the series of operations was performed has a cleanness of about 10,000, and there is a minute level of foreign matter on the glass plate. It is interpreted that it was embedded in the precursor film and did not manifest as a defect.

The polyimide layer was peeled from the obtained polyimide film layer / inorganic substrate laminate (E1), and the optical properties of the polyimide film (F1) were measured. The light transmittance at 400 nm was 85.2%, HAZE was 0.78%, and the yellowness was 2.41.

(Examples 2 to 7)
Polyimide precursor film layer / inorganic substrate laminate C2-C6 (polyimide precursor film is D2-D6), polyimide film layer / inorganic substrate in the same manner as in Example 1 using the polyamic acid solutions of Synthesis Examples A2-A6 Laminated bodies E2 to E6 (polyimide films were F2 to F6) were obtained.

Table 1 shows the thickness, thickness variation, and organic solvent content of each polyimide precursor film.

  The appearance quality of each of the laminates E2 to E6 was good, and the number of defects was as shown in Table 2.

The optical properties of the polyimide films were as shown in Table 3, respectively.

(Comparative Example 1)
The final film thickness (film thickness after imidization) of the polyamic acid solution (A1) is 20 μm on a smooth surface (non-sliding material surface) of a long polyethylene terephthalate film having a thickness of 125 μm and a width of 1050 mm using a slit die. And then dried at 120 ° C. for 15 minutes, and wound into a roll without sandwiching the separator film to obtain a polyimide precursor film roll (G1).

Thereafter, polyimide precursor film layer / inorganic substrate laminate H1 (polyimide precursor film is I1) and polyimide film layer / inorganic substrate laminate J1 (polyimide film is K1) were obtained in the same manner as in Example 1.

  The obtained polyimide precursor film (I1) had an average thickness of 23.1 μm, a maximum of 23.5 μm, a minimum of 22.8 μm, and a thickness unevenness of 3.03%. The organic solvent content was 24.9 wt%.

  In the laminate (J1), an average of 1.3 defects were observed on the polyimide film surface. It is presumed that foreign matter adhered or scratched during a series of operations because the separator film was not used.

The polyimide layer was peeled from the obtained polyimide film layer / inorganic substrate laminate (J1), and the optical properties of the polyimide film (F1) were measured. The light transmittance at 400 nm was 84.9%, the HAZE was 0.68%, and the yellowness was 2.45.

The film thickness, thickness unevenness, and optical properties of the polyimide precursor film and polyimide film obtained in Comparative Example 1 were not significantly different from those in Example 1, but differed in the number of defects depending on the presence or absence of the separator film at the time of roll winding. Was confirmed.

(Comparative Examples 2-6)
Polyamic acid solutions A2 to A6 are polyimide precursor film layers / inorganic substrate laminates H2 to H6 (polyimide precursor films are I1 to I6) and polyimide film layers in the same manner as in Example 1 except that no separator film is used. / Inorganic substrate laminates J2 to J6 (polyimide films are K2 to K6) were obtained.

Table 1 shows the thickness, thickness variation, and organic solvent content of each polyimide precursor film.

  Table 2 shows the number of defects in each of the laminates J2 to J6.

The optical properties of the polyimide films were as shown in Table 3, respectively.

The film thickness, thickness unevenness, and optical characteristics of the polyimide precursor film and polyimide film obtained in Comparative Examples 2 to 6 were not significantly different from those in Examples 2 to 6, but the presence or absence of a separator film at the time of roll winding. It was confirmed that there was a difference in the number of defects.

(Application 1)
Using the polyimide film layer / inorganic substrate laminate obtained in Examples 1 to 6, a bottom gate type thin film transistor array was prototyped by the following steps.
A 100 nm gas barrier film made of SiON was formed on the entire polyimide film side of the polyimide film layer / inorganic substrate laminate using a reactive sputtering method. Next, an aluminum layer having a thickness of 80 nm was formed by a sputtering method, and a gate wiring and a gate electrode were formed by a photolithography method. Next, an epoxy resin-based gate insulating film (thickness 80 nm) was formed using a slit die coater. Further, a 5 nm chromium layer and a 40 nm gold layer were formed by sputtering, and a source electrode and a drain electrode were formed by photolithography. Next, using a slit die coater, an epoxy resin serving as an insulating layer and dam layer is applied, and a 250-nm thick dam layer for a semiconductor layer including a source electrode and a drain electrode is formed by ablation with a UV-YAG laser with a diameter of 100 μm. The via was also formed at the same time as a connection point with the upper electrode. Next, polythiophene, which is an organic semiconductor, was coated in the dam by ink jet printing, a silver paste was buried in the via portion, and an aluminum wiring was formed as an upper electrode to form a thin film transistor array having 640 × 480 pixels.

  The obtained thin film transistor array was used as a back plane, and an electrophoretic display medium was overlaid on the front plane to form a display element. The yield and display performance of the transistor were determined by ON / OFF of each pixel. As a result, the thin film transistor arrays obtained in the examples all had good display performance.

  A polyimide film layer / inorganic substrate laminate with good quality can be obtained by using the polyimide precursor film roll including the separator film of the present invention. In the manufacturing process of flexible electronic devices or functional thin films where the polyimide film layer is held by a temporary support substrate and an electronic device or functional thin film is formed on the polyimide film layer, a uniform film thickness is achieved with few scratches and foreign matter At the same time, extremely high glass surface cleanliness is not required, and a high-quality polyimide film layer / inorganic substrate laminate can be obtained. As a result, a flexible electronic device can be obtained with a high yield. It becomes possible.

Claims (6)

A multi-layer film roll in which a multi-layer film having a width exceeding 500 mm and a length of 50 m or more is wound in a roll shape on a cylindrical winding core,
The multilayer film is
A polymer film substrate layer having a thickness of 12 μm or more and 190 μm or less,
A polyimide precursor layer having a thickness of 5 μm or more and 200 μm or less, a thickness spot of 20% or less, and an organic solvent in a proportion of 20% by mass or more and 35% by mass or less;
A separator film layer having a thickness of 5 μm or more and 130 μm or less,
A multilayer film roll characterized by having a structure in which the layers are sequentially laminated.   The multilayer film roll according to claim 1, wherein the reduced viscosity of the polyimide precursor is 0.5 dL / g or more and 5.0 dL / g or less.   3. The multilayer film roll according to claim 1, wherein an absolute value of a thickness unevenness of the polymer film substrate layer is 10 μm or less.   The multilayer film roll according to any one of claims 1 to 3, wherein an absolute value of thickness unevenness of the separator film layer is 10 µm or less.   5. The roundness of the inner diameter of the cylindrical winding core is 99.87% or more, and the roundness of the outer diameter is 99.87% or more. Multi-layer film roll. A winding core having an inner diameter roundness of 99.87% or more and an outer diameter roundness of 99.87% or more, using a winding core mounted so that the eccentricity is 200 μm or less,
An organic solvent solution of a polyimide precursor is applied to a polymer film substrate having a thickness of 12 μm or more and 190 μm or less and an absolute value of the thickness unevenness of 10 μm or less. Dry so as to be in the range of 20% by mass or more and 35% by mass or less with respect to the total amount of the solvent,
6. The separator film according to claim 1, further comprising a separator film having a thickness of 5 μm or more and 130 μm or less and an absolute value of thickness unevenness of 10 μm or less stacked on the layer containing the polyimide precursor and the solvent. A method for producing a multilayer film roll described in any one of the above.