TW202138433A - Polyimide film and laminate - Google Patents

Abstract

A polyimide film formed from a polyimide resin, wherein the radius of curvature R when laminated onto a silicon substrate of thickness 520 µm is greater than 20 m.

Description

Polyimide film and laminate

The present invention relates to polyimide films and laminates.

In the fields of electrical and electronic parts, in order to reduce the weight and flexibility of devices, it is desired to replace glass substrates with plastic substrates. In particular, electronic circuit substrates undergo various steps such as sputtering steps and etching steps for forming polysilicon films, metal oxide films such as indium tin oxide (ITO) films, semiconductor films, etc., to produce a desired electronic circuit on the substrate. Therefore, the plastic substrate requires heat resistance. Research on polyimide films suitable as such plastic substrates is ongoing, and development is also ongoing for laminates that use polyimide films as electronic circuit substrates.

For example, Patent Document 1 discloses that in order to obtain a flexible display that can respond to substrate warpage, lighting test, white turbidity test, and thermal cycle test, it contains a polyimide containing aminophenyl aminobenzoate as a constituent component. A flexible display with a polyimide film layer and a low-temperature polysilicon TFT layer formed on the polyimide film layer. In addition, Patent Document 2 discloses that in order to obtain a polyimide laminate with suppressed warpage, a step of forming a polyimide layer on the support while conveying the long support, and the polyimide A method for manufacturing a polyimide laminate in which the tensile elastic modulus of the layer and the support, the thickness of the support, and the fracture toughness of the support are set to specific values. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2019-070811 [Patent Document 2] Japanese Patent Application Publication No. 2019-182974

[The problem to be solved by the invention]

In order to ensure the flatness of the polyimide film in the manufacturing process of the electronic circuit for the purpose of making the polyimide film, there is a method of processing the polyimide film by bonding the polyimide film to a hard support such as a glass plate. At this time, if the glass substrate is warped, it will cause troubles in the manufacturing process of electronic circuits. In addition, the polyimide film on which the electronic circuit is formed requires a step of peeling from the support after the manufacturing process. If the polyimide film is curled after peeling, the subsequent manufacturing process of the image display device will result. Troubled. Neither the aforementioned Patent Documents 1 and 2 discuss warpage. According to the method disclosed in Patent Document 1, the molecular structure of polyimide is limited. According to the method disclosed in Patent Document 2, the method disclosed in the aforementioned Patent Document 2 is used to transport a long roll of support. It is not possible to use glass substrates and the like. Therefore, a polyimide film with less warpage and curling during the manufacturing process, and a laminate using the polyimide film with less warpage are required.

The present invention is made in view of such a situation, and aims to provide a polyimide film with less warpage and curling during the manufacturing process and a laminate with less warpage. [Means to solve the problem]

The inventors of the present invention have found that the above-mentioned problems can be solved by using polyimide whose radius of curvature is a specific value. The present invention has been completed based on such findings.

式(1)中，C(Pa･m² )表示利用下式(2)求得之常數，S(Pa)表示聚醯亞胺薄膜的應力，t(m)表示聚醯亞胺薄膜的厚度。 [數2]

式(2)中，E表示作為基板之矽(100)的楊氏模量(Pa)，ν表示作為基板之矽(100)的泊松比(Poisson’s ratio)，h表示矽基板的厚度(m)。 ＜2＞一種疊層體，係將如上述＜1＞所記載之聚醯亞胺薄膜疊層於玻璃基板或矽基板上而成。 ＜3＞如上述＜2＞所記載之疊層體，其中，於前述聚醯亞胺薄膜上更疊層有金屬膜或半導體膜。 ＜4＞如上述＜3＞所記載之疊層體，其中，前述半導體膜係選自於由氧化銦錫、非晶矽、銦-鎵-鋅氧化物及低溫多晶矽構成之群組中之至少1種。 ＜5＞如上述＜2＞～＜4＞中任一項所記載之疊層體，其中，前述玻璃基板與前述聚醯亞胺薄膜之間或前述矽基板與前述聚醯亞胺薄膜之間具有犧牲層。 ＜6＞一種聚醯亞胺薄膜之製造方法，具有下列步驟：將疊層於厚度520μm之矽基板而得之聚醯亞胺薄膜的應力S(Pa)及該聚醯亞胺薄膜的厚度t(m)調整為符合下式(3)。 [數3]

式(3)中，C(Pa･m² )表示利用下式(2)求得之常數。 [數4]

式(2)中，E表示作為基板之矽(100)的楊氏模量(Pa)，ν表示作為基板之矽(100)的泊松比，h表示矽基板的厚度(m)。 ＜7＞一種疊層體之製造方法，包含下列步驟：將如上述＜1＞所記載之聚醯亞胺薄膜或利用如上述＜6＞所記載之製造方法得到的聚醯亞胺薄膜疊層於玻璃基板或矽基板上。 ＜8＞一種導電性薄膜，係從如上述＜2＞～＜5＞中任一項所記載之疊層體或利用如上述＜7＞所記載之製造方法得到的疊層體剝離去除玻璃基板或矽基板而得。 [發明之效果]That is, the present invention relates to the following. <1> A polyimide film made of polyimide resin, wherein the radius of curvature R when the following formula (1) is laminated on a silicon substrate with a thickness of 520 μm is greater than 20 m. [Number 1]

In the formula (1), C(Pa･m ² ) represents the constant obtained by the following formula (2), S(Pa) represents the stress of the polyimide film, and t(m) represents the thickness of the polyimide film . [Number 2]

In formula (2), E represents the Young's modulus (Pa) of the silicon (100) as the substrate, ν represents the Poisson's ratio (Poisson's ratio) of the silicon (100) as the substrate, and h represents the thickness of the silicon substrate (m ). <2> A laminated body formed by laminating the polyimide film described in the above <1> on a glass substrate or a silicon substrate. <3> The laminate as described in the above <2>, wherein a metal film or a semiconductor film is further laminated on the polyimide film. <4> The laminate as described in the above <3>, wherein the semiconductor film is at least selected from the group consisting of indium tin oxide, amorphous silicon, indium-gallium-zinc oxide, and low-temperature polysilicon 1 kind. <5> The laminate according to any one of the above <2> to <4>, wherein between the glass substrate and the polyimide film or between the silicon substrate and the polyimide film With sacrificial layer. <6> A manufacturing method of a polyimide film, which has the following steps: the stress S (Pa) of the polyimide film obtained by laminating a silicon substrate with a thickness of 520 μm and the thickness t of the polyimide film (m) is adjusted to conform to the following formula (3). [Number 3]

In the formula (3), C(Pa･m ² ) represents the constant obtained by the following formula (2). [Number 4]

In the formula (2), E represents the Young's modulus (Pa) of the silicon (100) as the substrate, ν represents the Poisson's ratio of the silicon (100) as the substrate, and h represents the thickness (m) of the silicon substrate. <7> A method of manufacturing a laminate, comprising the following steps: laminating the polyimide film as described in the above <1> or the polyimide film obtained by the manufacturing method as described in the above <6> On glass substrate or silicon substrate. <8> A conductive film, which is peeled and removed from the laminated body as described in any one of the above <2> to <5> or the laminated body obtained by the manufacturing method as described in the above <7> Or derived from a silicon substrate. [Effects of Invention]

According to the present invention, it is possible to provide a polyimide film with less warpage and curl during the manufacturing process, and a laminate with less warpage.

Hereinafter, an embodiment of the present invention will be described. The content of the present invention is not limited to the embodiments described below. In addition, in this manual, the terms "A to B" in the description of numerical values mean "A and B or more" (A<B) or "A or B and B or more" (A>B) . Furthermore, in the present invention, a combination of ideal aspects is a more ideal aspect.

式(1)中，C(Pa･m² )表示利用下式(2)求得之常數，S(Pa)表示聚醯亞胺薄膜的應力，t(m)表示聚醯亞胺薄膜的厚度。 [數6]

式(2)中，E表示作為基板之矽(100)的楊氏模量(Pa)，ν表示作為基板之矽(100)的泊松比，h表示矽基板的厚度(m)。[Polyimide film] The polyimide film of the present invention is composed of polyimide resin, wherein the radius of curvature R when the following formula (1) is laminated on a silicon substrate with a thickness of 520 μm is greater than 20 m . [Number 5]

In the formula (1), C(Pa･m ² ) represents the constant obtained by the following formula (2), S(Pa) represents the stress of the polyimide film, and t(m) represents the thickness of the polyimide film . [Number 6]

In the formula (2), E represents the Young's modulus (Pa) of the silicon (100) as the substrate, ν represents the Poisson's ratio of the silicon (100) as the substrate, and h represents the thickness (m) of the silicon substrate.

In the past, the warpage and curling of polyimide films, and the warpage of laminates obtained by laminating polyimide films, have mostly used the linear thermal expansion of the polyimide resin constituting the polyimide film. Coefficient (CTE) to judge, and implement the design of the resin with a small CTE. However, the actual warpage, curling phenomenon and the value of CTE may not be consistent. In addition, it is particularly required to suppress warpage and curling during the process of peeling from the support. In this case, the present inventors found that by satisfying the aforementioned conditions, a polyimide film with less warpage and curling during the manufacturing process can be obtained, and a laminate with less warpage using the polyimide film can be obtained. Layer body.

The polyimide film of the present invention has a radius of curvature R greater than 20 m when the polyimide film represented by the following formula (1) is laminated on a silicon substrate with a thickness of 520 μm. [Number 7]

In the formula (1), C (unit: Pa･m ² ) represents a constant obtained by the following formula (2). S (unit: Pa) represents the stress of the polyimide film, and t (unit: m) represents the thickness of the polyimide film.

[Number 8]

In formula (2), E represents the Young's modulus (unit: Pa) of silicon (100) as the substrate, ν represents the Poisson's ratio of silicon (100) as the substrate, and h represents the thickness of the silicon substrate (unit: m ). E is the Young's modulus of silicon (100) as the substrate, which is 130 GPa. ν represents the Poisson's ratio of silicon (100) as the substrate, which is 0.28. E/(1-ν) is the biaxial elastic modulus of the substrate. In the case of a silicon (100) substrate, it is 1.805×10 ¹¹ Pa. In addition, the (100) plane represents the so-called Miller index. In addition, h is the thickness of the silicon substrate (unit: m). In the case of a silicon substrate with a thickness of 520 μm, the constant C is 8134.

The stress of the polyimide film corresponding to S in the aforementioned formula (1) is preferably 42 MPa or less, more preferably 40 MPa or less, and even more preferably 30 MPa or less. The lower limit is not limited, and the stress of the polyimide film corresponding to S in the aforementioned formula (1) is 0 MPa or more. For convenience in this paragraph, 10 ⁶ Pa is expressed in MPa. The stress of the polyimide film will vary depending on the manufacturing method, thickness, etc. even if the composition of the polyimide resin is the same. For example, it depends on the orientation of the extension. Therefore, when the polyimide film is used in the production of conductive films, etc. described later, the S (stress of the polyimide film) and t (thickness of the polyimide film) in the aforementioned formula (1) are set Actually, it should be implemented under the same conditions as those of the actual manufacturer.

The thickness of the polyimide film corresponding to t in the aforementioned formula (1) is preferably 1-20 μm, more preferably 3-15 μm, and even more preferably 5-10 μm. For convenience in this paragraph, 10 ^-6 m is expressed in μm. If the thickness of the polyimide film is within this range, the polyimide film will not be damaged in the manufacture of electronic devices, and the manufacture of electronic devices is easier, and it can be stabilized from glass substrates or silicon substrates after the manufacture of electronic devices. Peel off. In addition, the film thickness of the polyimide film can be determined by physical measurement using a micrometer or the like, or optical observation using a laser microscope, etc., and measuring the height of the top surface of the film and the contact surface with the substrate.

Considering the above point of view, the ideal combination of S and t mentioned above, when S is 30×10 ⁶ ～42×10 ⁶ Pa, it should be t series 1×10 ^-6 ～10×10 ^-6 m combination, which is t series The combination of 1×10 ^-6 ～8×10 ^-6 m is more preferable, and the combination of t series 1×10 ^-6 ～5×10 ^-6 m is even more preferable. In addition, when S is 0×10 ⁶ ～30×10 ⁶ Pa, the combination of t series 5×10 ^-6 ～20×10 ^-6 m is suitable, and t series 5×10 ^-6 ～15×10 ^-6 The combination of m is more preferable, and the combination of t is 5×10 ^-6 ～10×10 ^-6 m is even more preferable.

As mentioned above, the polyimide film of the present invention is considered to reduce the warpage and curling in the manufacturing process, and also from the viewpoint of reducing the warpage of the laminated body, the aforementioned formula (1) is laminated on a silicon substrate with a thickness of 520μm The radius of curvature R at this time is larger than 20m (meters), preferably 40m or more, and more preferably 70m or more. The upper limit is not limited. In consideration of making the film formation of the polyimide film and the subsequent processing process easier, it is preferably less than 1000m, more preferably less than 500m, and even more preferably less than 300m. When the radius of curvature R of the polyimide film laminated on a silicon substrate with a thickness of 520 μm is in the aforementioned range, the warpage of the substrate during the process is small, and the warpage of the polyimide film after peeling from the substrate is also Small, so ideal.

(Characteristics of polyimide film) The ideal physical properties of the polyimide film of the present invention are as follows.

When the total light transmittance is made into a film with a thickness of 10 μm, it is preferably 88% or more, more preferably 88.5% or more, and even more preferably 89% or more. When the yellow index (YI) is made into a film with a thickness of 10 μm, it is preferably 4.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less. If the total light transmittance or yellow index falls within these ranges, it is suitable as a resin substrate for flexible electronic devices.

When the haze is made into a film with a thickness of 10 μm, it is preferably 2.0% or less, more preferably 0.6% or less, and even more preferably 0.4% or less. If the haze falls within this range, it is suitable as a resin substrate for flexible electronic devices.

(Polyimide resin) The polyimide film of the present invention is composed of polyimide resin. The polyimide resin constituting the polyimide film of the present invention has a structural unit A derived from tetracarboxylic dianhydride and a structural unit B derived from diamine. In addition, ideal examples of the polyimide resin that can be used in the present invention are illustrated below, but the present invention is not limited to this.

[Construction Unit A] The structural unit A is a structural unit derived from tetracarboxylic dianhydride which is occupied in the polyimide resin. The structural unit A is not limited as long as it is a structural unit derived from tetracarboxylic dianhydride, and the ideal structural unit and its combination will be described below.

The constituent unit A preferably contains at least one selected from the group consisting of the constituent unit (A1) derived from alicyclic tetracarboxylic dianhydride and the constituent unit (A2) derived from the compound represented by the general formula (a2) described later The structural unit, preferably including the structural unit (A1). It is even more preferable to include both of the structural unit (A1) and the structural unit (A2).

The constituent unit A includes the constituent unit (A1) derived from alicyclic tetracarboxylic dianhydride, so that the colorless transparency and optical isotropy of the film can be improved. The aforementioned alicyclic tetracarboxylic dianhydride is preferably selected from 1,2,4,5-cyclohexanetetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro- 2``-norbornane-5,5'',6,6''-tetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-ring Consisting of alicyclic tetracarboxylic dianhydride such as pentanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, and dicyclohexyltetracarboxylic dianhydride At least 1 in the group. Among them, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5 as listed below ,5'',6,6''-tetracarboxylic dianhydride is more preferred.

The structural unit (A1) preferably contains at least 1 selected from the group consisting of the structural unit (A11) derived from the compound represented by the following formula (a11) and the structural unit (A12) derived from the compound represented by the following formula (a12) It is more preferable that the structural unit includes the structural unit (A11) derived from the compound represented by the following formula (a11).

[化1]

The compound represented by formula (a11) is norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid two Anhydride (CpODA). By including the constituent unit (A11) in the constituent unit A, the colorlessness and transparency of the film will be more improved.

The compound represented by formula (a12) is 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA). The constituent unit (A1) includes the constituent unit (A12) to improve the colorless transparency and optical isotropy of the film.

The structural unit A may also include both the structural unit (A11) and the structural unit (A12), but preferably includes either the structural unit (A11) or the structural unit (A12), and the structural unit (A11) is more preferably included. good.

The structural unit (A2) is a structural unit derived from a compound represented by the following general formula (a2).

[化2]

In formula (a2), L is a single bond or a divalent linking group. The aforementioned divalent linking group is preferably a substituted or unsubstituted alkylene group, which is -CR ¹ R ^2- (here, R ¹ and R ² are each independently a hydrogen atom or a substituted or unsubstituted alkyl group, or It is more ^{preferable that R 1} and R ^{2 are} bonded to each other to form a ring). L is preferably one selected from the group consisting of a single bond, a group represented by the following formula (L1), a group represented by the following formula (L2), and a group represented by the following formula (L3). In addition, in the following formula (L1), the following formula (L2), and the following formula (L3), * represents the bonding site with the aromatic ring.

[化3]

The structural unit (A2) is preferably selected from the structural unit (A21) from the compound represented by the following formula (a21), the structural unit (A22) from the compound represented by the following formula (a22), and the structural unit (A22) from the compound represented by the following formula (a23) At least one of the group consisting of the constituent unit (A23) of the compound and the constituent unit (A24) from the compound represented by the following formula (a24) is selected from the group consisting of the compound represented by the following formula (a21) At least one of the structural unit (A21) and the structural unit (A22) from the compound represented by the following formula (a22) is more preferably at least one of the group consisting of the structural unit (A21) derived from the compound represented by the following formula (a21) Better.

[化4]

The compound represented by the formula (a21) is biphenyltetracarboxylic dianhydride (BPDA), and specific examples thereof can be cited: 3,3',4,4'-biphenyltetracarboxylic dianhydride (s- BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA) represented by the following formula (a21a), 2,2',3,3'-linked represented by the following formula (a21i) Pyromellitic dianhydride (i-BPDA).

[化5]

The compound represented by the formula (a22) is 9,9'-bis(3,4-dicarboxyphenyl) dianhydride (BPAF). The compound represented by formula (a23) is 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA). The compound represented by formula (a24) is 4,4'-oxydiphthalic anhydride (ODPA).

When structural unit A contains at least one selected from the group consisting of structural unit (A1) and structural unit (A2), the total content ratio of structural unit (A1) and structural unit (A2) in structural unit A Preferably it is more than 50 mol%, more preferably more than 55 mol%, more preferably more than 60 mol%, more preferably more than 80 mol%, more preferably more than 90 mol%, more preferably more than 95 mol% Ear% or more is better. The upper limit of the total content ratio of the structural unit (A1) and the structural unit (A2) is not particularly limited, and is 100 mol% or less. The structural unit A may consist of only the structural unit (A1) and the structural unit (A2).

When structural unit A includes structural unit (A1) and structural unit (A2), the molar ratio [(A1)/(A2)] of structural unit (A1) and structural unit (A2) should be 10/90～95/5 , More preferably 40/60～90/10, even more preferably 50/50～85/15.

The structural unit A may include structural units other than the structural unit (A1) and the structural unit (A2). The tetracarboxylic dianhydride providing such a structural unit is not particularly limited, and examples include: pyromellitic dianhydride, 3,3',4,4'-diphenyl tetracarboxylic dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, Aromatic tetracarboxylic dianhydrides such as 2,3,3',4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride; and 1,2,3,4 -Aliphatic tetracarboxylic dianhydrides such as butane tetracarboxylic dianhydride. In addition, in this specification, aromatic tetracarboxylic dianhydride means tetracarboxylic dianhydride containing more than one aromatic ring, and alicyclic tetracarboxylic dianhydride refers to containing more than one alicyclic ring and no aromatic Cyclic tetracarboxylic dianhydride and aliphatic tetracarboxylic dianhydride mean tetracarboxylic dianhydride that does not contain an aromatic ring or an alicyclic ring. The structural unit optionally contained in the structural unit A may be one type or two or more types.

[Construction Unit B] The structural unit B is a structural unit derived from a diamine which is accounted for in the polyimide resin. The structural unit B is not limited as long as it is a structural unit derived from a diamine, and the ideal structural unit and its combination are described below.

The constituent unit B preferably includes a constituent selected from the constituent unit (B1) derived from the fluorine-containing aromatic diamine, the constituent unit (B2) derived from the compound represented by the following formula (b2), and the composition derived from the compound represented by the following formula (b3) Unit (B3), structural unit (B4) derived from the compound represented by formula (b4) described below, structural unit (B5) derived from the compound represented by formula (b5) described below, structural unit (B5) derived from the compound represented by formula (b6) described below B6), and at least one structural unit from the group consisting of the structural unit (B7) of the compound represented by the general formula (b7) described below, including those selected from the group consisting of the structural unit (B1) and the structural unit (B2) It is more preferable to include at least one type of structural unit in the group, and it is even more preferable to include the structural unit (B1). When the structural unit (B1) is included, it is preferable to include at least one structural unit selected from the group consisting of the structural unit (B2) and the structural unit (B7), and it is more preferable to include the structural unit (B7).

The structural unit (B1) is a structural unit (B1) derived from a fluorine-containing aromatic diamine, and is preferably a structural unit (B11) derived from a compound represented by the following general formula (b11).

[化6]

In the formula (b11), X is a single bond or an oxygen atom.

The aforementioned structural unit (B11) preferably contains at least one selected from the group consisting of the structural unit (B111) derived from the compound represented by the following formula (b111) and the structural unit (B112) derived from the compound represented by the following formula (b112) One type of structural unit preferably includes a structural unit (B111) derived from the compound represented by the following formula (b111).

[化7]

The compound represented by the formula (b111) is 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA).

The compound represented by the formula (b112) is 2,2'-bis(trifluoromethyl)benzidine (TFMB).

The ratio of the structural unit (B1) in the structural unit B is preferably 20 mol% or more, more preferably 50 mol% or more, and even more preferably 80 mol% or more. The upper limit is not particularly limited, that is, the ratio of the structural unit (B1) in the structural unit B is 100 mol% or less.

When the structural unit B includes the structural unit (B1), it can also be used in combination with the structural unit described later. When the structural unit B includes the structural unit (B111) in the structural unit (B1), it is preferable to include the structural unit (B7). When structural unit B includes structural unit (B111) and structural unit (B7), the molar ratio of structural unit (B1) and structural unit (B7) [(B1)/(B7)] should be 90/10 to 99/1 , More preferably 95/5～98/2.

The structural unit (B2) is a structural unit derived from the compound represented by the following formula (b2).

[化8]

In the above formula (b2), R is independently selected from the group consisting of a hydrogen atom, a fluorine atom, and an alkyl group having 1 to 5 carbon atoms, and is preferably selected from the group consisting of a hydrogen atom, a fluorine atom, and a methyl group. In the group composed of radicals, a hydrogen atom is more preferable. The compound represented by the above formula (b2) may include: 9,9-bis(4-aminophenyl) fluoride (BAFL), 9,9-bis(3-fluoro-4-aminophenyl) fluorine, and 9 , 9-bis(3-methyl-4-aminophenyl) sulfonate, etc., preferably at least one selected from the group consisting of these three compounds, considering the heat resistance point of view, it is 9,9 -Bis(4-aminophenyl) pyridium is more preferred.

The ratio of the constituent unit (B2) in the constituent unit B is preferably 40 mol% or more. The upper limit is not particularly limited, that is, the ratio of the structural unit (B2) in the structural unit B is 100 mol% or less.

When the structural unit B includes the structural unit (B2), it can also be used in combination with other structural units. When the structural unit B contains the structural unit derived from 9,9-bis(4-aminophenyl) sulfide in the structural unit (B2), it is preferable to contain the aforementioned structural unit (B112). When the structural unit B contains the structural unit derived from 9,9-bis(4-aminophenyl) sulfide and the structural unit (B112), the structural unit (B112) is preferably contained on the condition of 60 mol% or less.

The structural unit (B3) is a structural unit derived from the compound represented by the following formula (b3).

[化9]

The compound represented by the formula (b3) is bis(aminomethyl)cyclohexane (BAC), and specific examples thereof include: 1,3-bis(aminomethyl)cyclohexane represented by the following formula (b3a) ( 1,3-BAC), 1,4-bis(aminomethyl)cyclohexane (1,4-BAC) represented by the following formula (b3b).

式(b3)表示之化合物的順式：反式比，考慮耐有機溶劑性、耐熱性等之觀點，宜為0：100～80：20，為0.1：99.9～70：30更佳，為0.5：99.5～60：40再更佳，為1：99～20：80又更佳。[化10]

The cis:trans ratio of the compound represented by formula (b3), considering organic solvent resistance, heat resistance, etc., is preferably 0:100 to 80:20, more preferably 0.1:99.9 to 70:30, and is 0.5 ：99.5～60:40 is even more preferable, and 1:99～20:80 is even more preferable.

The structural unit (B4) is a structural unit derived from the compound represented by the following formula (b4).

[化11]

The compounds represented by the formula (b4) include: compounds represented by the following formula (b41) (that is, 4,4'-diaminodiphenyl sulfide (4,4'-DDS)) and those represented by the following formula (b42) Compounds (ie 3,3'-diaminodiphenyl sulfonium (3,3'-DDS)) and the like.

[化12]

The structural unit (B4) is preferably at least one selected from the group consisting of the structural unit (B41) derived from the compound represented by the formula (b41) and the structural unit (B42) derived from the compound represented by the formula (b42). The constitution unit (B4) may be only the constitution unit (B41), may be only the constitution unit (B42), or may be a combination of the constitution unit (B41) and the constitution unit (B42).

The structural unit (B5) is a structural unit derived from the compound represented by the following formula (b5).

[化13]

The compound represented by formula (b5) is 1,5-diaminonaphthalene (DAN).

The structural unit (B6) is a structural unit derived from the compound represented by the following formula (b6).

[化14]

The compound represented by the formula (b6) is 4,4'-diaminobenzaniline.

The structural unit (B7) is a structural unit derived from a compound represented by the following general formula (b7). The structural unit (B7) is preferably used in combination with other structural units, and at least one selected from the group consisting of structural units (B1) to (B6) is more preferably used in combination, and the structural unit (B1) should be used in combination. Better.

The ratio of the constituent unit (B7) in the constituent unit B is preferably 1-10 mol%, more preferably 2-5 mol%.

[化15]

In formula (b7), Z ¹ and Z ² each independently represent a divalent aliphatic group or a divalent aromatic group that may also contain an oxygen atom, and R ¹ and R ² each independently represent a monovalent aromatic group or 1 R ³ and R ⁴ each independently represent a monovalent aliphatic group, R ⁵ and R ⁶ each independently represent a monovalent aliphatic group or a monovalent aromatic group, and m and n each independently represent 1 or more The sum of m and n represents an integer ranging from 2 to 1000. In addition, in formula (b7), the two or more different repeating units described in [] are not related to the order of [], and may be in any of random, alternating, or block shapes and order. To repeat.

In the formula (b7), the divalent aliphatic group or the divalent aromatic group ^{in Z 1} and Z ^{2 may be substituted with a fluorine atom.} Examples of the divalent aliphatic group include a divalent saturated or unsaturated aliphatic group having 1 to 20 carbon atoms, and an aliphatic group containing an oxygen atom. The carbon number of the divalent aliphatic group is preferably 3-20. Examples of the divalent saturated aliphatic group include alkylene groups with 1 to 20 carbon atoms, such as methylene, ethylene, propylene, trimethylene, tetramethylene, hexamethylene, and octamethylene. Methyl, decamethylene, dodecamethylene, etc. Examples of the divalent unsaturated aliphatic group include alkenylene groups having 2 to 20 carbon atoms, such as vinylene groups, propenylene groups, and alkenylene groups having an unsaturated double bond at the end. The aliphatic group containing an oxygen atom includes an alkyleneoxy group and an aliphatic group having an ether bond. The alkyleneoxy group can be exemplified by propyleneoxy group, trimethyleneoxy group, and the like. The divalent aromatic group can be exemplified by an arylene group having 6 to 20 carbon atoms, an aralkylene group having 7 to 20 carbon atoms, and the like. Specific examples of the arylene group having 6 to 20 carbon atoms in Z ¹ and Z ² include: o-phenylene, meta-phenylene, p-phenylene, 4,4'-biphenylene, 2,6 -Naphthyl and so on. Z ¹ and Z ^{2 are} particularly preferably trimethylene and p-phenylene, and more preferably trimethylene.

In the formula (b7), ^{examples of the monovalent aliphatic group in R 1} to R ⁶ include a monovalent saturated or unsaturated aliphatic group. Examples of the monovalent saturated aliphatic group include alkyl groups having 1 to 22 carbon atoms, and examples thereof include methyl, ethyl, and propyl. Examples of the monovalent unsaturated aliphatic group include alkenyl groups having 2 to 22 carbon atoms, and examples thereof include vinyl groups and propenyl groups. These groups may also be substituted by fluorine atoms. ^{The monovalent aromatic group in R 1} , R ² , R ⁵ and R ⁶ of the formula (b7) can be exemplified: an aryl group having 6 to 20 carbons, an aryl group substituted with an alkyl group having 7 to 30 carbons, and carbon Aralkyl group of 7 to 30, etc. The monovalent aromatic group is preferably an aryl group, more preferably a phenyl group. In R ¹ and R ² is suitably at least one of a monovalent aromatic group, R ¹ and R ² are both a divalent aromatic group more preferably, R ¹ and R ² are both phenyl and still more preferably. R ³ and R ^{4 are} preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group. R ⁵ and R ^{6 are} preferably monovalent aliphatic groups, more preferably methyl.

As described above, among the compounds represented by the above general formula (b7), the compound represented by the following formula (b71) is preferred.

式(b71)中，m及n分別和式(b7)中之m及n同義，理想的範圍亦為同樣。[化16]

In formula (b71), m and n are synonymous with m and n in formula (b7), respectively, and the ideal range is also the same.

In formula (b7) and formula (b71), m represents the repeating number of siloxane units bonded with at least one monovalent aromatic group, and n in formula (b7) and formula (b71) represents bonding with 1 The repeating number of the siloxane unit of the valence aliphatic group. M and n in formula (b7) and formula (b71) each independently represent an integer of 1 or more, and the sum (m+n) of m and n represents an integer of 2 to 1000. The sum of m and n preferably represents an integer of 3 to 500, more preferably 3 to 100, and even more preferably an integer of 3 to 50. The ratio of m/n in formula (b7) and formula (b71) is preferably 5/95-50/50, more preferably 10/90-40/60, and even more preferably 20/80-30/70.

The functional group equivalent (amine equivalent) of the compound represented by the formula (b7) 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. In addition, the functional group equivalent means the mass of the compound represented by formula (b7) per mole of functional group (amine group).

Among the compounds represented by the above general formula (b7), those that can be obtained in the form of commercially available products include: "X-22-9409", "X-22-1660B", and "X- 22-161A", "X-22-161B", etc.

The constituent unit B includes the constituent unit (B7) to improve the colorlessness, transparency, optical isotropy, and flexibility of the film.

The structural unit B may include structural units other than the structural units (B1) to (B7). The diamine that provides such a structural unit is not particularly limited, and examples include 1,4-phenylene diamine, p-xylylenediamine, 2,2'-dimethylbiphenyl-4,4'-diamine , 4,4'-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)hexafluoropropane, 3,4'-diaminodiphenyl ether, 1-(4-amino) Phenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-5-amine, N,N'-bis(4-aminophenyl)p-xylylenedimethamide, Aromatic diamines such as 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 1,4-bis(4-aminophenoxy)benzene; alicyclic diamines; and ethyl Aliphatic diamines such as diamine and hexamethylene diamine. In addition, in this specification, aromatic diamine means diamine containing more than one aromatic ring, alicyclic diamine means diamine containing more than one alicyclic ring and no aromatic ring, aliphatic diamine It means a diamine that does not contain aromatic or alicyclic rings. The structural unit optionally contained in the structural unit B may be one type or two or more types.

(Manufacturing method of polyimide resin) The polyimide resin of the present invention can be produced by reacting the above-mentioned tetracarboxylic acid component as the compound providing the structural unit A with the above-mentioned diamine component as the compound providing the structural unit B.

The compound providing the constituent unit A may include the compound represented by the formula (a11), the compound represented by the formula (a12), and the compound represented by the formula (a2) described in the column of [Constructive Unit A], but it is not limited thereto. In the range where the same structural unit can be provided, derivatives thereof may also be used. Examples of the derivative include tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the aforementioned formulas, and alkyl esters of the tetracarboxylic acid. Among them, tetracarboxylic dianhydride represented by the aforementioned formulas is preferred.

The tetracarboxylic acid component may include any compound other than the compound providing the structural unit (A1) and the compound providing the structural unit (A2). Such optional compounds include: the above-mentioned aromatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aliphatic tetracarboxylic dianhydrides, and their derivatives (tetracarboxylic acid, alkyl group of tetracarboxylic acid) Esters, etc.). The compound optionally contained in the tetracarboxylic acid component may be one type or two or more types.

The compound that provides the constituent unit B includes the compound represented by the formula (b11), the compound represented by the formula (b2), the compound represented by the formula (b3), and the compound represented by the formula (b4) described in the column of the aforementioned [Constructive Unit B] The compound, the compound represented by the formula (b5), the compound represented by the formula (b6), and the compound represented by the formula (b7), but not limited to these, may also be derivatives thereof within the range that the same structural unit can be provided. Examples of the derivatives include diisocyanates corresponding to the compounds represented by the aforementioned formulas. Among them, the compounds represented by the aforementioned formulas (that is, diamines) are preferable.

The diamine component may include any compound other than the compound that provides the aforementioned structural units (B1) to (B7). Examples of such optional compounds include the above-mentioned aromatic diamines, alicyclic diamines, and aliphatic diamines, and their derivatives (diisocyanates, etc.). The compound optionally contained in the diamine component may be one type or two or more types.

The feed ratio of the tetracarboxylic acid component and the diamine component used in the production of the polyimide resin is preferably 1 mol relative to the tetracarboxylic acid component, and the diamine component is preferably 0.9 to 1.1 mol.

In addition, in the production of the polyimide resin, in addition to the aforementioned tetracarboxylic acid component and diamine component, a terminal blocking agent can also be used. The terminal blocking agent is preferably monoamine or dicarboxylic acid. The feed amount of the introduced end-capping agent is preferably 0.0001 to 0.1 mol, preferably 0.001 to 0.06 mol, relative to 1 mol of the tetracarboxylic acid component. Recommended monoamine end-capping agents such as methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylamine Benzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline, etc. Among them, benzylamine and aniline can be preferably used. The dicarboxylic acid end-capping agent is preferably a dicarboxylic acid, and a part of it may be ring closed. Recommended examples: phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid , Cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, etc. Among them, phthalic acid and phthalic anhydride can be preferably used.

The method of reacting the said tetracarboxylic-acid component and diamine component is not specifically limited, A well-known method can be used. Specific reaction methods include: (1) The tetracarboxylic acid component, the diamine component, and the reaction solvent are fed into the reactor, stirred at 10 to 110°C for 0.5 to 30 hours, and then the temperature is raised to implement the imine The method of chemical reaction, (2) After the diamine component and the reaction solvent are fed into the reactor and dissolved, the tetracarboxylic acid component is fed, and the mixture is stirred at 10 to 110°C for 0.5 to 30 hours, and then carried out. The method of carrying out the imidization reaction by raising the temperature, (3) the method of feeding the tetracarboxylic acid component, the diamine component, and the reaction solvent into the reactor, and immediately raising the temperature to carry out the imidization reaction, etc.

The reaction solvent used in the production of the polyimide resin may be one that can dissolve the produced polyimide resin without hindering the imidization reaction. Examples include aprotic solvents, phenolic solvents, ether solvents, carbonate solvents, and the like.

Specific examples of aprotic solvents include: N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactone Amine solvents such as amine, 1,3-dimethylimidazolidinone and tetramethylurea; lactone solvents such as γ-butyrolactone and γ-valerolactone; hexamethylphosphamide, hexamethyl Phosphorus-containing amine-based solvents such as phosphine triamide; sulfur-containing solvents such as dimethyl sulfide, dimethyl sulfide, and cyclobutane; ketone-based solvents such as acetone, cyclohexanone, and methyl cyclohexanone; Amine solvents such as pyridine and pyridine; ester solvents such as (2-methoxy-1-methylethyl) acetate, etc.

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, 3,5-xylenol, etc. Specific examples of ether solvents include: 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, Bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, 1,4-dioxane and the like. In addition, specific examples of carbonate-based solvents include diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, and the like. Among the above-mentioned reaction solvents, an amide-based solvent or a lactone-based solvent is preferable. Moreover, the said reaction solvent may be used individually or in mixture of 2 or more types.

It is preferable to use a Dean-Stark apparatus or the like for the imidization reaction, and the reaction is carried out while removing water generated during production. By performing such an operation, the degree of polymerization and the rate of imidization can be further increased.

A well-known imidation catalyst can be used for the said imidation reaction. Examples of the imidization catalyst include alkali catalysts and acid catalysts. Examples of base catalysts include pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, Tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, N,N-diethylaniline and other organic base catalysts; potassium hydroxide, or sodium hydroxide, potassium carbonate, carbonic acid Inorganic alkali catalysts such as sodium, potassium bicarbonate and sodium bicarbonate. Also, acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, hydroxybenzoic acid, terephthalic acid, benzenesulfonic acid, and p-toluenesulfonic acid. , Naphthalenesulfonic acid, etc. The above-mentioned imidization catalyst may be used alone or in combination of two or more kinds. Among the above, considering the operability, it is preferable to use an alkali catalyst, more preferably an organic alkali catalyst, more preferably triethylamine and triethylenediamine, and particularly preferably triethylamine.

The temperature of the imidization reaction is preferably 120 to 250°C, and more preferably 160 to 200°C, in consideration of the reaction rate and the inhibition of gelation. In addition, the reaction time is preferably 0.5 to 10 hours after the start of the distillation of the produced water.

The solid content concentration during the imidization reaction is preferably 30 to 60% by mass, more preferably 35 to 58% by mass, and particularly preferably 40 to 56% by mass. If the solid content concentration during the imidization reaction falls within this range, the imidization reaction proceeds well, and the water generated during the reaction is easily removed, so the polymerization degree and the imidization rate can be increased. However, the solid content concentration during the imidization reaction is a value calculated from the following formula based on the mass of the tetracarboxylic acid component added to the reaction system, the diamine component in the reaction system, and the reaction solvent. Solid content concentration during the imidization reaction (mass%) = (total mass of tetracarboxylic acid component and diamine component)/(total mass of tetracarboxylic acid component, diamine component, and reaction solvent)×100

(Characteristics of polyimide resin) The glass transition temperature (Tg) of the polyimide resin constituting the polyimide film in the present invention is preferably 230°C or higher, more preferably 250°C or higher, and even more preferably 270°C or higher. In addition, when the polyimide film is used as a substrate for TFT, it is more preferably 400°C or higher, and even more preferably 430°C or higher. If it falls within this range, the heat resistance when manufacturing the touch sensor substrate or when manufacturing the TFT is good.

式(1)中，C(Pa･m² )表示利用下式(2)求得之常數，S(Pa)表示聚醯亞胺薄膜的應力，t(m)表示聚醯亞胺薄膜的厚度。 [數10]

式(2)中，E表示作為基板之矽(100)的楊氏模量(Pa)，ν表示作為基板之矽(100)的泊松比，h表示矽基板的厚度(m)。[Method for producing polyimide film] The method for producing polyimide film of the present invention is not particularly limited. If the obtained polyimide film is selected to be a polyimide film composed of polyimide resin, And it is only required to be a method of manufacturing a method in which the radius of curvature R when laminated on a silicon substrate with a thickness of 520 μm, represented by the following formula (1), is greater than 20 m. [Number 9]

In the formula (1), C(Pa･m ² ) represents the constant obtained by the following formula (2), S(Pa) represents the stress of the polyimide film, and t(m) represents the thickness of the polyimide film . [Number 10]

In the formula (2), E represents the Young's modulus (Pa) of the silicon (100) as the substrate, ν represents the Poisson's ratio of the silicon (100) as the substrate, and h represents the thickness (m) of the silicon substrate.

式(3)中，C(Pa･m² )表示利用下式(2)求得之常數。 [數12]

式(2)中，E表示作為基板之矽(100)的楊氏模量(Pa)，ν表示作為基板之矽(100)的泊松比，h表示矽基板的厚度(m)。In order to obtain such a polyimide film, the manufacturing method of the polyimide film of the present invention preferably has the stress S (Pa) of the polyimide film obtained by laminating a silicon substrate with a thickness of 520 μm and the polyimide film. The thickness t(m) of the imine film is adjusted to conform to the step of the following formula (3). [Number 11]

In the formula (3), C(Pa･m ² ) represents the constant obtained by the following formula (2). [Number 12]

In the formula (2), E represents the Young's modulus (Pa) of the silicon (100) as the substrate, ν represents the Poisson's ratio of the silicon (100) as the substrate, and h represents the thickness (m) of the silicon substrate.

As mentioned above, the stress S of the polyimide film may vary depending on the manufacturing method and the like even if the composition of the polyimide resin is the same. Therefore, it is advisable to have a step of adjusting the stress S of the polyimide film and the thickness t of the polyimide film laminated on a silicon substrate with a thickness of 520 μm to conform to the aforementioned formula (3), and this step should be adjusted to The film is manufactured under the same conditions as the actual manufacturing user. Specifically, after measuring the stress of a polyimide film made to an arbitrary thickness, the thickness of the polyimide film is adjusted, and the stress S of the polyimide film and the thickness of the polyimide film are adjusted It is ideal to make t conform to the steps of the aforementioned formula (3). On the other hand, when the thickness of the polyimide film must be set within a specific range in consideration of its use, etc., this step is to select a polyimide resin with a known stress of the film of different thickness in advance, and combine the polyimide resin The thickness of the polyimide film is adjusted to be within the aforementioned specific range, and the stress S of the polyimide film and the thickness t of the polyimide film are adjusted to meet the steps of the aforementioned formula (3).

<Production of polyimide film using polyimide varnish> Specific methods for producing polyimide films include, for example, coating the polyimide varnish on a smooth support such as glass plates, metal plates, plastics, etc., or after forming into a thin film, heating the varnish Methods for removing organic solvents such as reaction solvents and diluting solvents.

Examples of the coating method of the varnish include well-known coating methods such as spin coating, slit coating, and knife coating. Among them, considering the viewpoints of controlling the intermolecular alignment, improving chemical resistance, reducing interference patterns, and workability, stitch coating is ideal. The method of using heating to remove the organic solvent contained in the varnish is preferably at a temperature above the boiling point of the organic solvent used after the organic solvent is evaporated and becomes non-viscous at a temperature of 150°C or less under atmospheric pressure or reduced pressure (It is preferably 200-500°C, but not particularly limited) for drying. The pressure of the dry environment can be any of reduced pressure, normal pressure, and increased pressure. It is ideal to perform drying under normal pressure or reduced pressure air environment or normal pressure or reduced pressure oxygen concentration below 100 ppm nitrogen environment, preferably normal pressure or reduced pressure oxygen concentration below 10 ppm nitrogen environment.

The polyimide varnish used in the production of the polyimide film is made by dissolving polyimide resin in an organic solvent. That is, the polyimide varnish contains a polyimide resin and an organic solvent, and the polyimide resin is dissolved in the organic solvent. The organic solvent is not particularly limited as long as it can dissolve the polyimide resin, and the above-mentioned compound as the reaction solvent used in the production of the polyimide resin is preferably used alone or in combination of two or more. The polyimide varnish may be the polyimide solution itself in which the polyimide resin obtained by the polymerization method is dissolved in the reaction solvent, or it may be obtained by further adding a diluting solvent to the polyimide solution.

The above polyimide resin has solvent solubility, so it can be made into a high-concentration varnish that is stable at room temperature. The polyimide varnish preferably contains 2-40% by mass of polyimide resin, and more preferably contains 3-30% by mass. The viscosity of the polyimide varnish is preferably 0.1～200Pa･s, more preferably 0.3～100Pa･s, and even more preferably 1～100Pa･s. The viscosity of the polyimide varnish is a value measured at 25°C using an E-type viscometer. In addition, the polyimide varnish may contain inorganic fillers, adhesion promoters, release agents, flame retardants, ultraviolet stabilizers, surfactants, and stabilizers within the range that does not impair the properties required by the polyimide film. Various additives such as leveling agent, defoaming agent, fluorescent whitening agent, crosslinking agent, polymerization initiator, sensitizer, etc. The manufacturing method of polyimide varnish is not specifically limited, A well-known method can be used.

<Manufacturing of polyimide film using polyimide varnish and varnish of polyimide-glycine copolymer> The polyimide film can also be produced using a polyimide varnish obtained by dissolving polyimide in an organic solvent. The polyamide contained in the aforementioned polyamide varnish is preferably a precursor of the polyimide resin. The precursor of the polyimide resin, polyamide acid, is the product of the addition polymerization reaction of the above-mentioned tetracarboxylic acid component and the above-mentioned diamine component. By subjecting these polyimide acids to imidization (dehydration and ring closure), a polyimide resin, which is the final product, can be obtained.

In addition, a varnish of an amide-amide acid copolymer can also be used. The amide-amide acid copolymer is made by adding a tetracarboxylic acid component and a diamine component step by step to make it stepwise. The method of chemical conversion, etc., and a part of it is formed by imidization. By using such a copolymer varnish, the stability of the varnish and the reactivity of the resin can be balanced.

As the organic solvent contained in the aforementioned polyimide varnish and the varnish of the imine-amine acid copolymer, the organic solvent contained in the polyimide varnish can be used. In the present invention, the polyamide varnish may be the polyamide solution itself obtained by the addition polymerization reaction of the tetracarboxylic acid component and the diamine component in the reaction solvent, or it may be the polyamide acid solution It is made by adding further dilution solvent.

There are no particular limitations on the method of using a polyimide varnish or a varnish of an imine-amine acid copolymer to produce a polyimide film, and a known method can be used. For example, polyamide varnish or varnish of imine-amide copolymer can be coated on a smooth support such as glass plate, metal plate, plastic, etc., or formed into a film, and heated Organic solvents such as reaction solvent and dilution solvent contained in the varnish are removed to obtain a polyamide acid film or an imine-amide acid copolymer film, and then heating is used to make the polyamide acid in the polyamide acid film Carry out imidization to produce polyimide film. The heating temperature when drying the polyamide varnish or the varnish of the imine-amide acid copolymer to obtain the polyamide acid film or the imine-amide acid copolymer film is preferably 50 to 120°C. The heating temperature when the polyamide part is imidized by heating is preferably 200 to 400°C. In addition, the method of imidization is not limited to thermal imidization, and chemical imidization can also be used.

[Laminated body and manufacturing method of laminated body] In the laminated system of the present invention, the aforementioned polyimide film is laminated on a glass substrate or a silicon substrate. The laminated body of the present invention is suitable for bonding a polyimide film on a glass substrate or a silicon substrate. The aforementioned polyimide film is directly adhered to the glass substrate or silicon substrate, or in order to be easily peeled off after the manufacturing process, there is a sacrificial layer, peeling layer, and adhesive layer between the aforementioned glass substrate or silicon substrate and the aforementioned polyimide film. The junction layer is better, and the sacrificial layer is even better. In addition, the laminate of the present invention can be manufactured by any method, but it is preferably manufactured by the following method. That is, the manufacturing method of the laminated body of the present invention preferably includes the polyimide film described in the section of [Polyimide film], or the use of the section of [Production method of polyimide film] The step of laminating the polyimide film obtained by the manufacturing method of the polyimide film on a glass substrate or a silicon substrate.

(Glass substrate or silicon substrate) The glass substrate or the silicon substrate is not particularly limited, as long as it has the strength to support the polyimide film when manufacturing an electronic device (conductive film) using the polyimide film as the substrate. There is no particular limitation on the type of glass, and alkali-free glass (borosilicate glass), alkali glass, soda glass, non-fluorescent glass, phosphoric acid glass, boric acid glass, quartz, etc. can be used. In order to achieve good adhesion with the polyimide film, the flatness of the top surface of the glass substrate or silicon substrate should be high. Specifically, the surface roughness Rmax is preferably 10 μm or less, and Rmax is more preferably 1 μm or less.

(Sacrificial layer) As mentioned above, the laminate of the present invention preferably has a sacrificial layer between the glass substrate and the polyimide film or between the silicon substrate and the polyimide film. The method of peeling off the polyimide film is as follows: a structure containing polyimide/support is obtained, and then the polyimide resin interface is ablated by irradiating a laser from the support side. , Thereby peeling off the polyimide resin. At this time, it is preferable to use a sacrificial layer between the polyimide film and the glass substrate. The types of lasers include solid (YAG) lasers, gas (UV excimer) lasers, and can use spectrums such as 308nm. The sacrificial layer is preferably formed of amorphous silicon, titanium film or aluminum film. The sacrificial layer can absorb almost most of the laser light, so the amorphous silicon can radiate heat due to the laser light irradiation, and use the heat to crystallize and expand the volume. As a result, a low adhesion state in which the polyimide film is partially peeled from the sacrificial layer can be obtained, and the peeling becomes easy, which is preferable. The sacrificial layer may be formed of a metal film such as titanium (Ti) and aluminum (Al), or may be formed of an amorphous silicon (a-Si) film or the like. When the sacrificial layer is composed of a metal film, for example, it is preferable to form it so as to have a thickness of 100 to 500 nm by using a sputtering method. When the sacrificial layer is composed of an a-Si film, for example, it is preferable to form the sacrificial layer in a thickness of 100 to 500 nm by using a CVD method or a sputtering method. If it falls within this range, a laser can be used to easily peel off the polyimide film, which is ideal.

(Metal film or semiconductor film) The laminate of the present invention is preferably further laminated with a metal film or a semiconductor film on the polyimide film. By laminating a metal film or a semiconductor film on the polyimide film, electronic devices (conductive films) such as touch sensors and OLEDs can be fabricated on the polyimide film. Preferable specific examples of the metal film include copper mesh, silver mesh, and the like. A desirable specific example of the semiconductor film can include at least one selected from the group consisting of indium tin oxide (ITO), amorphous silicon, indium-gallium-zinc oxide (IGZO), and low-temperature polysilicon (LTPS). It is also possible to laminate other metal films or semiconductor films on these metal films or semiconductor films. The thickness of the metal film or semiconductor film is not particularly limited, and is preferably 10 to 400 nm, more preferably 20 to 200 nm, and even more preferably 30 to 150 nm.

[Conductive film] A conductive thin film can be obtained by peeling and removing a glass substrate or a silicon substrate from the aforementioned laminate on which a metal film or a semiconductor film is laminated. That is, the conductive film of the present invention is peeled and removed from the laminated body described in the section of the aforementioned [Laminated body and the manufacturing method of the laminated body] or the laminated body obtained by the method of manufacturing the laminated body. Derived from silicon substrate. A conductive film can be made by laminating a metal film or a semiconductor film on a polyimide film, and then peeling off the glass substrate or silicon substrate immediately to obtain a conductive film. It can also be stored in a laminated state and respond accordingly. It is necessary to peel off the glass substrate or the silicon substrate to obtain a conductive film. By storing in the state of a laminate, the operability of the conductive film during transportation is improved, which is preferable.

The method of peeling and removing the glass substrate or the silicon substrate from the laminated body is not particularly limited. For the laminated body of the present invention, the polyimide film can be easily and stably peeled from the glass substrate or the silicon substrate, so it can be mechanically Ground peeling instead of laser irradiation. [Example]

Hereinafter, the present invention will be specifically explained using examples. However, the present invention is not limited in any way by these embodiments.

[Physical property measurement, film evaluation] In the examples and comparative examples, the measurement of each physical property and the evaluation of the film were implemented by the methods shown below. (1) Film thickness (t) The film thickness was measured using a laser microscope (manufactured by KEYENCE Co., Ltd.).

(2) Glass transition temperature (Tg) Using the thermomechanical analysis device "TMA/SS6100" (manufactured by Hitachi High-Tech Science Co., Ltd.), the temperature was raised to the temperature in the tensile mode under the conditions of a sample size of 2mm×20mm, a load of 0.1N, and a heating rate of 10°C/min. The temperature is sufficient to remove the residual stress to remove the residual stress, and then it is cooled to room temperature. Thereafter, the measurement of the extensibility of the test piece was carried out under the same conditions as the above-mentioned treatment for removing the residual stress, and the temperature at which the inflection point of the extensibility was observed was determined as the glass transition temperature.

(3) Total light transmittance, yellow index (YI) The total light transmittance and YI are measured in accordance with JIS K7105:1981, using a color-turbidity simultaneous measuring device "COH400" (manufactured by Nippon Denshoku Industries Co., Ltd.).

(4) Haze The measurement was performed in accordance with JIS K7361-1: 1997, using a color-turbidity simultaneous measuring device "COH7700" manufactured by Nippon Denshoku Industries Co., Ltd.

(5) Coefficient of linear thermal expansion (CTE) Using the thermomechanical analysis device "TMA/SS6100" manufactured by Hitachi High-Tech Science Co., Ltd., the TMA measurement was carried out under the conditions of a sample size of 2mm×20mm, a load of 0.1N, and a heating rate of 10°C/min in the tensile mode. Calculate the CTE at 100～200℃ or 100～350℃. The table shows each measurement temperature range (100 to 200°C or 100 to 350°C).

(6) Stress (S) The residual stress measuring device "FLX-2320" manufactured by KLA-Tencor was used to obtain the stress of the polyimide film. For the measurement, a silicon wafer (silicon substrate) with a thickness of 520 μm and a diameter of 4 inches with a blank value measured in advance was used. On the silicon wafer, the varnish obtained in each manufacturing example was coated under the conditions of each embodiment and comparative example, and heat treatment was performed under the conditions of each embodiment and comparative example to produce silicon laminated with polyimide film Wafer, and available for measurement.

(7) Film warpage On the alkali-free glass AN100 (thickness 0.7mm, size 10cm×10cm, manufactured by AGC Co., Ltd.), the varnish obtained in each production example was coated under the conditions of each example and comparative example, and the varnish of each example and comparative example Condition heat treatment to produce glass laminated with polyimide film. On the polyimide film, a polyester film (grade TM3075T, thickness 75μm, manufactured by Sun A. Kaken Co., Ltd.) provided with an acrylic adhesive as a support for measuring the amount of film warpage was attached to the polyimide film. Use a utility knife to cut an 8cm×8cm size cut on the polyimide-polyester laminate, and peel off the polyimide-polyester laminate film from the glass. Place the peeled film on the platform, measure the distance between the four corners of the film and the platform with a ruler, and find the minimum and maximum values of warpage. The smaller the value of any value, the smaller the warpage of the film and the better it is. In addition, since the polyimide films used in the examples and comparative examples were thin and difficult to handle, a polyester film was used as a support to evaluate the amount of warpage of the polyimide film. The upper limit of the measured value is 10cm, and those exceeding the upper limit are indicated as ">10" in the table.

(8) Warpage of laminated body On the alkali-free glass AN100 (thickness 0.5mm, size 15cm×15cm, manufactured by AGC Co., Ltd.), the varnish obtained in each production example was coated under the conditions of each example and comparative example, and the varnish of each example and comparative example Under the conditions, heat treatment is performed to produce a laminate with polyimide film laminated. The laminated body was placed on a platform, and the distance between the end of the laminated body and the platform was measured using a gap meter. This distance was evaluated as the amount of warpage of the laminate. The smaller the value of the warpage of the laminated body, the smaller the warpage of the laminated body and the better.

[raw material] The tetracarboxylic acid component, diamine component, other components, and their abbreviations used in the production examples are as follows. ＜Tetracarboxylic acid component＞ CpODA: Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (JX Energy Co., Ltd. Company) s-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation) BPAF: 9,9'-bis(3,4-dicarboxyphenyl) dianhydride ＜Diamine component＞ 6FODA: 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (manufactured by ChinaTech (Tianjin) Chemical Co., Ltd.) X-22-1660B-3: Amino modified silicone oil at both ends (manufactured by Shin-Etsu Chemical Co., Ltd. (functional group equivalent: 2200 g/mol)) BAFL: 9,9-bis(4-aminophenyl)sulfonate TFMB: 2,2’-bis(trifluoromethyl)benzidine ＜Other＞ GBL: γ-butyrolactone (manufactured by Mitsubishi Chemical Corporation) TEA: Triethylamine (manufactured by Kanto Chemical Co., Ltd.) NMP: N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation)

[Manufacturing of Varnish] Manufacturing example 1 Put 26.953 g (0.0802 mol) into a 500 mL 5-neck round bottom flask equipped with stainless steel half-moon stirring blades, nitrogen introduction tube, Dean-Stark device with cooling tube, thermometer, and glass end cap. The 6FODA and 56.000g of NMP were stirred at a rotation speed of 200rpm under a system internal temperature of 70°C under a nitrogen environment to obtain a solution. In this solution, 19.231g (0.050 mol) of CpODA and 14.000g of NMP were added all at once, then 0.253g of TEA as an imidization catalyst was put in, and it was heated with a mantle heater. It took about 20 minutes to raise the temperature in the reaction system to 190°C. The distilled components were collected, and the rotation speed was adjusted to increase the viscosity while maintaining the internal temperature of the reaction system at 190°C and refluxing for 1 hour. After that, 85.806 g of NMP was added, and the temperature in the reaction system was cooled to 50° C. to obtain a solution containing an oligomer having repeating structural units of imine. To the obtained solution, 9.814 g (0.033 mol) of s-BPDA and 7.527 g of NMP were added all at once, and stirred at 50°C for 5 hours. Then, after adding 100.000 g of NMP and homogenizing it, put in a mixed solution in which 14.002 g (0.003 mol) of X-22-1660B-3 was dissolved in 16.667 g of NMP, and then stirred for about 1 Within hours, a varnish of an imine-amic acid copolymer with a solid content concentration of about 20% by mass was obtained.

Manufacturing example 2 Put 26.227g (0.0780 mol) in a 500mL 5-neck round bottom flask equipped with stainless steel half-moon stirring blades, nitrogen introduction tube, Dean-Stark device with cooling tube, thermometer, and glass end cap. The 6FODA and 109.317g of NMP were stirred at a rotation speed of 200 rpm under a nitrogen environment at an internal temperature of 50°C to obtain a solution. Into this solution, 23.536g (0.0800 mol) of s-BPDA and 27.329g of NMP were put into this solution at once, and the mixture was stirred for 7 hours while keeping the temperature at 50°C with a heating pack. Then, after adding 83.66 g of NMP and homogenizing it, 8.800 g (0.0020 mol) of X-22-1660B-3 (functional group equivalent of 2200 g/mol) dissolved in 13.940 g of NMP was added. After that, the temperature was raised to 80° C. and the mixture was stirred for 1 hour and then returned to room temperature to obtain a polyamide varnish having a solid content of 20% by mass.

Manufacturing example 3 Put 25.503 g (0.073 mol) into a 500 mL 5-neck round bottom flask equipped with stainless steel half-moon stirring blades, nitrogen introduction tube, Dean-Stark device with cooling tube, thermometer, and glass end cap. The BAFL and 100.113g GBL were stirred at a rotation speed of 200rpm under a nitrogen environment at an internal temperature of 70°C to obtain a solution. Put 28.130 g (0.073 mol) of CpODA and 25.028 g of GBL into this solution, and then add 0.370 g of TEA as an imidization catalyst. Heating was carried out with a heating bag, and the temperature in the reaction system was raised to 190°C over about 30 minutes. The distilled components were collected while stirring for 5 hours. Then, GBL was added so that the solid content concentration might become 10 mass %, and after cooling the temperature to 100 degreeC, it stirred for about 1 hour and made it homogenized, and the polyimide varnish was obtained.

Manufacturing example 4 Put 10.956 g (0.034 mol) in a 500 mL 5-neck round bottom flask equipped with stainless steel half-moon stirring blades, nitrogen introduction tube, Dean-Stark device with cooling tube, thermometer, and glass end cap. TFMB, 9.766g (0.028 mol) of BAFL and 70.182g of GBL were stirred at a system internal temperature of 70°C and a nitrogen environment at 200 rpm to obtain a solution. Put 12.253g (0.031 mol) of CpODA, 14.262g (0.031 mol) of BPAF, and 17.546g of GBL into the solution, and then add 3.142g of TEA as an imidization catalyst and 0.035g of triple extension Ethylenediamine. Heating was carried out with a heating bag, and the temperature in the reaction system was raised to 190°C over about 30 minutes. The distilled components were collected while stirring for 5 hours. Then, GBL was added so that the solid content concentration might become 10 mass %, and after cooling the temperature to 100 degreeC, it stirred for about 1 hour and made it homogenized, and the polyimide varnish was obtained.

[Manufacturing of Polyimide Film] Example 1 The varnish obtained in Manufacturing Example 1 was coated on a glass substrate (alkali-free glass AN100, thickness 0.7mm) by spin coating, and kept at 80°C on a hot plate for 20 minutes, and then in a hot air dryer under a nitrogen atmosphere Heat at 350°C for 30 minutes to evaporate and harden the solvent to form a polyimide film on the glass substrate. The polyimide film was peeled off and the physical properties were measured. The results are shown in Table 1. The amount of film warpage of the obtained polyimide film was measured. The results are shown in Table 2. In addition, the glass substrate was replaced with a silicon wafer, a polyimide film was produced in the same way, the polyimide film was laminated on the silicon wafer, and the stress S was measured. The radius of curvature R is shown in Table 2.

Example 2 The varnish obtained in Manufacturing Example 2 was coated on a glass substrate (alkali-free glass AN100, thickness 0.7mm) by spin coating, and kept on a hot plate at 80°C for 20 minutes. After that, in a hot air dryer in an air environment Heat at 260°C for 60 minutes to evaporate and harden the solvent to form a polyimide film on the glass substrate. The polyimide film was peeled off and the physical properties were measured. The results are shown in Table 1. The amount of film warpage of the obtained polyimide film was measured. The results are shown in Table 2. In addition, the glass substrate was replaced with a silicon wafer, a polyimide film was produced in the same way, the polyimide film was laminated on the silicon wafer, and the stress S was measured. The radius of curvature R is shown in Table 2.

Comparative example 1 The varnish obtained in Manufacturing Example 3 was coated on a glass substrate (alkali-free glass AN100, thickness 0.7mm) by spin coating, and held on a hot plate at 80°C for 20 minutes. After that, in a hot air dryer under a nitrogen atmosphere Heat at 400°C for 30 minutes to evaporate and harden the solvent to form a polyimide film on the glass substrate. The polyimide film was peeled off and the physical properties were measured. The results are shown in Table 1. The amount of film warpage of the obtained polyimide film was measured. The results are shown in Table 2. In addition, the glass substrate was replaced with a silicon wafer, a polyimide film was produced in the same way, the polyimide film was laminated on the silicon wafer, and the stress S was measured. The radius of curvature R is shown in Table 2.

[Manufacturing of laminated body] Examples 3 to 5 and Comparative Example 2 The varnish obtained in Production Example 4 was coated on a glass substrate (alkali-free glass AN100, thickness 0.5 mm) by spin coating, and the coating amount was changed in 4 steps, and dried on a hot plate at 80° C. for 20 minutes. After that, in a nitrogen atmosphere, heated in a hot air dryer at 400°C for 30 minutes to evaporate and harden the solvent to form 4 types of polyimide films with different thicknesses on the glass substrate to obtain a laminate on the glass substrate. The layer has a laminate of polyimide film. The polyimide film was peeled off and the physical properties were measured. The results are shown in Table 1 for a film with a thickness of 7.4 μm (Example 3). The amount of warpage of each laminate obtained was measured. The results are shown in Table 3. In addition, the glass substrate was replaced with a silicon wafer, and the coating amount was changed in four steps in the same manner to produce a polyimide film with the same thickness as the previous examples and comparative examples, and the polyimide film was laminated on the silicon. On the wafer, and measure the stress S. The radius of curvature R is shown in Table 3.

[Table 1] Example 1 Example 2 Comparative example 1 Example 3 Manufacture of varnish Manufacturing example 1 Manufacturing example 2 Manufacturing example 3 Manufacturing example 4 membrane thickness μm 10.0 9.2 10.0 7.4 Tg °C 320 259 480 440 Total light transmittance % 91 90 91 91 YI 1.9 4.2 1.3 1.8 Haze 0.1 0.1 0.5 0.5 CTE 100-200℃ ppm/℃ 34 44 53 - CTE 100-350℃ ppm/℃ - - - 25

[Table 2] Example 1 Example 2 Comparative example 1 Each value in formula (1) t ×10 ^-6 m 10.0 9.2 10.0 S ×10 ⁶ Pa 20.2 18.1 43.7 R m 40 49 19 CTE 100-200℃ ppm/℃ 34 65 53 Film warpage Minimum cm 2.5 1.5 ＞10 Maximum value cm 4.0 3.5 ＞10

[table 3] Example 3 Example 4 Example 5 Comparative example 2 Each value in formula (1) t ×10 ^-6 m 7.4 3 2.1 12 S ×10 ⁶ Pa 41 36 40 38 R m 27 75 97 18 CTE 100-350℃ ppm/℃ 25 25 25 25 Warpage of laminated body Maximum value mm 0.21 0.09 0.06 0.35

From the results of Table 2 and Table 3, it can be seen that the polyimide films and laminates of the examples have a small amount of warpage and warpage and curl regardless of the value of CTE.

Claims (8)

A polyimide film is composed of polyimide resin, wherein the radius of curvature R when the following formula (1) is laminated on a silicon substrate with a thickness of 520 μm is greater than 20 m;

In the formula (1), C(Pa･m ² ) represents the constant obtained by the following formula (2), S(Pa) represents the stress of the polyimide film, and t(m) represents the thickness of the polyimide film ；

In formula (2), E represents the Young's modulus (Pa) of the silicon (100) as the substrate, ν represents the Poisson's ratio (Poisson's ratio) of the silicon (100) as the substrate, and h represents the thickness of the silicon substrate (m ). A laminated body is formed by laminating the polyimide film of claim 1 on a glass substrate or a silicon substrate. The laminate of claim 2, wherein a metal film or a semiconductor film is further laminated on the polyimide film. The laminate of claim 3, 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 polysilicon. The laminate according to any one of claims 2 to 4, wherein a sacrificial layer is provided between the glass substrate and the polyimide film or between the silicon substrate and the polyimide film. A manufacturing method of a polyimide film has the following steps: the stress S (Pa) of the polyimide film obtained by laminating a silicon substrate with a thickness of 520 μm and the thickness t (m) of the polyimide film Adjust to meet the following formula (3);

In formula (3), C(Pa･m ² ) represents the constant obtained by the following formula (2);

In the formula (2), E represents the Young's modulus (Pa) of the silicon (100) as the substrate, ν represents the Poisson's ratio of the silicon (100) as the substrate, and h represents the thickness (m) of the silicon substrate. A method of manufacturing a laminate, comprising the following steps: laminating the polyimide film of claim 1 or the polyimide film obtained by the method of manufacturing the polyimide film of claim 6 on a glass substrate Or on a silicon substrate. A conductive thin film obtained by peeling and removing a glass substrate or a silicon substrate from the laminated body according to any one of claims 2 to 5 or the laminated body obtained by the method for manufacturing the laminated body according to claim 7.