TWI719184B - Polyimide resin laminate, its manufacturing method, and polyimide film with functional layer - Google Patents

Abstract

The polyimide resin laminate of the present invention is characterized by having a curl suppressing layer including a polyimide resin on one side of a carrier layer including a polyimide resin, and further having a curl suppressing layer that is releasably adhered to a curl suppressing layer. The thermal expansion coefficient of the curl-inhibiting layer of the base layer containing the polyimide resin of the layer is less than or greater than either of the thermal expansion coefficients of the support layer and the base layer.

Description

Polyimide resin laminate, its manufacturing method, and polyimide film with functional layer

The present invention relates to a liquid crystal display device, organic electroluminescence (EL) display, organic EL lighting, electronic paper, touch panel, and color filter formed on a polyimide substrate ( Color filter) and other functional layers of polyimide resin laminate and its manufacturing method.

Display devices such as liquid crystal display devices and organic EL display devices are widely used from large displays such as televisions to small displays such as mobile phones, personal computers, and smart phones. For example, an organic EL display device is manufactured by forming a thin film transistor (TFT) on a glass substrate, sequentially forming electrodes, light-emitting layers, electrodes, etc., and finally using a glass substrate or a multilayer film for airtight sealing.

Here, the type of the display device is not particularly limited, and includes display devices represented by liquid crystal display devices, organic EL display devices, electronic paper, and display device components such as color filters. In addition, it also includes various functional devices used with the display device, including organic EL lighting devices, touch panel devices, conductive films laminated with indium tin oxide (ITO), etc., to prevent moisture Or a gas barrier film that permeates oxygen, etc., a component part of a flexible circuit board, etc. That is, the so-called flexible element in the present invention includes not only constituent parts such as liquid crystal display devices, organic EL display devices, and color filters, but also organic EL lighting devices, touch panel devices, and electrode layers or light-emitting devices of organic EL display devices. One or a combination of two or more of layers, gas barrier films, adhesive films, thin film transistors (TFT), wiring layers of liquid crystal display devices, or transparent conductive layers.

By replacing the glass substrate with a resin base material, thickness reduction, weight reduction, and flexibility can be achieved, and the use of the display device can be further expanded. However, compared with glass, resin has problems such as poor dimensional stability, transparency, heat resistance, moisture resistance, and gas barrier properties.

For example, Patent Document 1 relates to an invention related to polyimide and its precursors useful as plastic substrates for flexible displays. It has been disclosed: the use of cyclohexyl phenyl tetracarboxylic acid, etc., containing an alicyclic structure Polyimides formed by reacting tetracarboxylic acids with various diamines are excellent in transparency. In addition, attempts have also been made to use flexible resin substrates instead of glass substrates to achieve weight reduction. For example, Non-Patent Document 1 and Non-Patent Document 2 propose organic EL display devices using highly transparent polyimide.

In this way, it is known that resin films such as polyimide are useful as supporting substrates for flexible displays, but the manufacturing steps of display devices have been performed using glass substrates, and most of the production equipment is designed on the premise of using glass substrates. . Therefore, it is ideal to effectively use existing production equipment and produce display devices.

As one of its research examples, there is the following method: a predetermined manufacturing process of a display device is completed in a state where a resin is laminated on a glass substrate, and then the glass substrate is removed, thereby manufacturing a display device having a display portion on a resin substrate ( Refer to Patent Document 2 to Patent Document 3, and Non-Patent Document 3 to Non-Patent Document 4). In the case of this method, it is important to separate the resin substrate from the glass without causing damage to the display portion formed on the resin substrate.

That is, in Patent Document 3 or Non-Patent Document 3, after a predetermined display portion is formed on a resin substrate coated on a glass substrate and fixed, it is called a plastic electronic laser release (Electronics on Plastic by Laser Release, The EPLaR process method irradiates a laser from the glass side to forcibly separate the resin substrate with the display part from the glass substrate. In addition, in Patent Document 2 or Non-Patent Document 4, after a release layer is formed on a glass substrate, a polyimide resin that is slightly larger than the release layer is applied to form a polyimide layer, and the cut that reaches the release layer is engraved. Thread, peel a small circle of polyimide film from the peeling layer.

On the other hand, when resin is laminated on a glass substrate, warpage becomes a big problem. That is, the coefficient of thermal expansion of the glass substrate is several ppm/K. In contrast, the resin generally has a coefficient of thermal expansion of several tens of ppm/K or more. Therefore, for example, if a resin solution is applied to a glass substrate and cured by heat treatment, etc. Form a resin layer and leave it to cool to room temperature, it will warp. If such warpage cannot be suppressed, it will adversely affect the formation of the subsequent display portion, etc.

In the step of using the polyimide laminate, the flexible display TFT substrate step usually uses In-Ga-Zn-O semiconductor (Indium Gallium Zinc Oxide (IGZO)) or low temperature polysilicon (Low Temperature Poly-Si). silicon, LTPS) construction method, subject to heat above 350°C. At this time, the thermal expansion coefficient of the glass substrate is several ppm/K. In contrast, the resin generally has a thermal expansion coefficient of several tens of ppm/K or more. Therefore, the laminate may be warped and the display portion may not be miniaturized.

In this regard, Patent Document 3 discloses that a resin layer (b) having a thermal expansion coefficient between the support substrate and the resin film (a) is provided between the support substrate and the resin film (a), but the effect of suppressing warpage is not full.

In addition, when a roll to roll (Roll to Roll; also referred to as “RTR” hereinafter) method is used to manufacture displays, touch panels, etc., the film that becomes the supporting substrate can withstand high temperature processing exceeding 300°C during the manufacturing process. , So it must be a material with excellent heat resistance. In addition, in consideration of light transmittance, a thin film is preferable. However, the handling of the film is difficult, and the production is also difficult. Currently, a transparent film with a thickness of 50 μm or more is used.

In addition, as a method that combines ease of handling or manufacturing with thinness, a transparent film with a carrier has been proposed. The laminated film with a carrier is formed by laminating a carrier film and a transparent substrate film without using an adhesive. After a functional layer such as a thin film transistor is formed on the transparent substrate, it is then laminated to the front panel, and then the carrier film is peeled off Therefore, it is possible to combine the operability in the manufacturing process and the thinness as a transparent support substrate in a display or a touch panel.

However, the conventional laminated film with a carrier tends to warp (curl), and the operability in the manufacturing step is very poor.

Patent Document 4 discloses that in order to suppress the occurrence of warpage, a first polyimide layer having a smaller thermal expansion coefficient is provided on a support such as a glass substrate, and a second polyimide layer having a larger thermal expansion coefficient than the support is provided on the support. However, it does not disclose research related to a support containing a heat-resistant resin that is not a glass substrate. [Prior Art Literature]

[Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2008-231327 [Patent Document 2] Japanese Patent No. 4834758 [Patent Document 3] Japanese Patent No. 5408848 [Patent Document 4] Japanese Patent Laid-Open 2015-182393 Bulletin

[Non-Patent Document] [Non-Patent Document 1] S. An et al., "2.8-inch WQVGA Flexible AMOLED (2.8-inch WQVGA Flexible AMOLED) Using High-performance Low-Temperature Polycrystalline Silicon Thin Film Transistors on Plastic Substrates Performance Low Temperature Polysilicon TFT on Plastic Substrates", Information Display Association 2010 Abstract (SID2010 DIGEST), p706 (2010) [Non-Patent Document 2] Oishi et al., "Transparent PI for Flexible Display flexible display", International Display Workshops (IDW)'11 FLX2/FMC4-1 [Non-Patent Document 3] EI Haskal and others, "Flexible OLED displays manufactured using EPLaR process OLED Displays Made with the EPLaR Process", Proc. Eurodisplay'07, pp.36～39 (2007) [Non-Patent Document 4] Cheng-Chung Lee et al., "Manufacturing Flexible Initiative A Novel Approach to Make Flexible Active Matrix Displays", SID10 Digest, pp.810～813 (2010)

[Problems to be Solved by the Invention] Therefore, the object of the present invention is to provide a polyimide resin laminate and a method of manufacturing the same, which is used as a substitute for glass in displays or touch panels. The polyimide resin laminate with a carrier of the substrate, and even when the heat-resistant resin that can be applied in the RTR process is used as the carrier material, it can maintain the operability in the manufacturing process and the display or touch Control the thickness of the support substrate in the panel, and minimize warpage (curl), and the support substrate can be easily and simply separated from the carrier material. [Technical means to solve the problem]

Therefore, the inventors of the present invention made diligent studies to solve these problems. As a result, it was surprisingly discovered that a predetermined polyimide resin-containing crimp was laminated on one side of a predetermined polyimide resin-containing substrate layer. The suppression layer and the predetermined carrier layer containing the polyimide resin can maintain the workability or the thinness of the substrate, and improve the warpage (curling), thereby completing the present invention.

That is, the present invention is a polyimide resin laminate, which is a laminate of a curl suppression layer containing a polyimide resin, a carrier layer containing a polyimide resin, and a base layer containing a polyimide resin And it is characterized in that: a curl-inhibiting layer and a carrier layer are adhered in a peelable manner on one side of the substrate layer, and the coefficient of thermal expansion (CTE) of the layer in contact with the substrate layer is less than or greater than Any of the CTEs of other layers.

The polyimide resin laminate of the present invention preferably has a curl suppressing layer including a polyimide resin on one side of a carrier layer including a polyimide resin, and further has a curl suppressing layer adhered to the curl suppressing layer in a peelable manner. The base material layer containing polyimide resin of the layer, the coefficient of thermal expansion (CTE) of the curl-inhibiting layer is less than or greater than any one of the coefficient of thermal expansion (CTE) of the support layer and the base material layer; or, when the polyimide resin is contained One side of the carrier layer has a substrate layer containing polyimide resin bonded in a peelable manner, and the opposite side of the carrier layer has a curl suppression layer containing polyimide resin, and the thermal expansion of the carrier layer The coefficient (CTE) is less than or greater than any one of the coefficient of thermal expansion (CTE) of the base layer and the curl suppression layer.

The polyimide resin laminate of the present invention preferably has a difference in coefficient of thermal expansion (CTE) between the base layer and the carrier layer, or a difference in coefficient of thermal expansion (CTE) between the base layer and the curl suppression layer of ±40 ppm/K or less.

The polyimide resin laminate of the present invention can be preferably used as a polyimide resin laminate in which a curl suppression layer and a substrate layer are formed on one side of a carrier layer to form a functional layer, or as a polyimide resin laminate in a carrier layer. A functional layer-equipped polyimide resin laminate in which a functional layer is further formed on one side with a base layer interposed therebetween.

In addition, the polyimide resin laminate of the present invention preferably has a base layer with a total light transmittance of 80% or more and a thickness of 50 μm or less, and is preferably made of polyimide resin forming the base layer. Tg is 300°C or higher.

Another embodiment of the present invention is a polyimide film with a functional layer, which uses the polyimide resin laminate with a functional layer, at the interface between the curl suppression layer and the substrate layer, or the carrier The interface between the layer and the base layer is peeled off, and the carrier layer and the curl suppression layer are removed.

In addition, the present invention is a method of manufacturing a polyimide resin laminate, which is a method of manufacturing the polyimide resin laminate, and is characterized by forming a curl suppression layer and a base material on a carrier layer by a casting method Floor.

In this manufacturing method, it is preferable to integrally harden the curl suppression layer and the base material layer coated on the carrier layer, and it is preferable that the casting method is coating using a multilayer die or a continuous die. [Effects of the invention]

According to the present invention, it is possible to maintain the operability in the manufacturing process and the thinness as a supporting substrate in a display or touch panel, and to suppress warpage (curling) as much as possible, which can meet the requirements of polyamide in the use of a display or touch panel. Required characteristics of amine resin laminates.

First, the polyimide resin laminate of the present invention includes a carrier layer containing a polyimide resin. The carrier layer maintains the base layer of the film in a predetermined shape during the RTR process, and after forming a functional layer such as an ITO film via the base layer, it is peeled and removed from the base layer. Therefore, in order to adapt to the RTR process, flexibility and strengthening of the substrate layer are required to maintain strength, but transparency is not necessarily required. Therefore, the thickness of the carrier layer is larger than the base layer of the film, preferably 10 μm to 100 μm, more preferably 30 μm to 75 μm. In addition, the glass transition temperature (Tg) is preferably 300°C or higher, more preferably 300°C to 450°C, due to the requirement of heat resistance applicable to the high temperature process of RTR.

The polyimide resin laminate of the present invention is a curl suppression layer containing polyimide resin (hereinafter also referred to as "crimp suppression layer"), and a carrier layer containing polyimide resin (hereinafter also referred to as "carrier layer"). "), and a laminate of a polyimide resin-containing base layer (hereinafter also referred to as "base layer"), and is characterized in that curl suppression is adhered to one side of the base layer in a peelable manner Layer and carrier layer laminate. Furthermore, the polyimide resin laminate is characterized in that the coefficient of thermal expansion (CTE) of the layer in contact with the base layer is less than or greater than any of the CTEs of the other layers.

Here, the layer that is in contact with the base layer refers to either the curl suppression layer or the carrier layer. The other layer refers to the substrate layer and the carrier layer when the layer in contact with the substrate layer is the curl suppression layer, and the substrate layer and the carrier layer when the layer in contact with the substrate layer is the carrier layer. Curl suppression layer.

In addition, there are two forms of the polyimide resin laminate (form one and form two). Hereinafter, each form will be described in detail.

[Form 1] The polyimide resin laminate of form 1 has a curl suppressing layer on one side of the carrier layer, and further has a base layer that is peelably bonded to the curl suppressing layer, and the CTE of the curl suppressing layer is less than or It is greater than any of the CTE of the carrier layer and the substrate layer.

In addition, from the viewpoint of suppressing warpage, the CTE of the carrier layer is preferably close to the CTE of the substrate layer, and the difference in thermal expansion coefficient between the two (also called ΔCTE, "CTE difference") is preferably within ±15 ppm/K It is more preferable that the CTE difference of the substrate layer is within +15 ppm/K compared with the CTE of the carrier layer, that is, the CTE difference is 0 ppm/K to +15 ppm/K. In addition, for example, the CTE of the carrier layer is preferably 10 ppm/K to 85 ppm/K. The CTE difference here is "within ±15 ppm/K", which means that the CTE difference of the substrate layer is -15 ppm/K to +15 ppm/K compared with the CTE of the carrier layer.

A substrate layer is provided on one side of the carrier layer via a curl suppression layer described later. The substrate layer becomes a transparent substrate instead of glass, and after forming a functional layer such as an ITO film on it and completing the RTR process, the carrier layer is peeled and removed to support the functional layer. Therefore, the total light transmittance of the substrate layer is preferably 80% or more, and more preferably 90% or more. In view of the required characteristics of thinning, weight reduction, and flexibility, the thickness of the substrate layer is preferably as thin as possible, preferably 50 μm or less, and more preferably 5 μm to 25 μm. As described above, the CTE of the substrate layer is preferably similar to the CTE of the carrier layer, preferably 10 ppm/K to 80 ppm/K. In addition, since heat resistance that can be applied to the high-temperature process of RTR is required, the glass transition temperature (Tg) of the substrate layer is preferably 300°C or higher, and more preferably 300°C to 450°C. Since it is used as a resin substrate instead of glass, the elastic modulus of the substrate layer is preferably 2 GPa to 15 GPa, for example.

On one side of the carrier layer, there is a curl suppression layer containing a polyimide resin between the carrier layer and the base layer. From the viewpoint of adapting to the RTR process, the curl suppression layer is formed between the carrier layer and the substrate layer in order to suppress the warpage of the substrate layer with the carrier as much as possible, and the substrate is interposed between the carrier layer and the curl suppression layer. After forming functional layers such as ITO film and completing the RTR process, when the carrier layer is peeled off and removed, it is removed together with the carrier layer. Therefore, in order to try to suppress warpage (curling) in the RTR process, the thickness or thermal expansion coefficient is selected. Therefore, the thickness of the curl suppression layer is preferably 50 μm or less, and more preferably 5 μm to 30 μm. In addition, the glass transition temperature (Tg) is preferably 300°C or higher, more preferably 300°C to 450°C, due to the requirement of heat resistance applicable to the high temperature process of RTR.

The CTE of the curl suppression layer is selected in such a way that the difference between the CTE of the carrier layer and the substrate layer is relatively large. For example, the CTE of the carrier layer and the base material layer may not necessarily be the same, but it is preferable to select such that the CTE of the curl suppression layer has a difference of a certain level or more relative to the CTE of both the carrier layer and the base material layer.

Therefore, regarding the CTE of the curl suppression layer, the CTE difference from the carrier layer and the CTE difference from the substrate layer are preferably ±15 ppm/K or more, and more preferably a CTE difference in the range of -15 ppm/K to -60 ppm/K. In addition, the CTE of the curl suppression layer is preferably -10 ppm/K to 20 ppm/K. Here, the so-called CTE difference of "±15 ppm/K or more" means that the CTE difference of the curl suppression layer is greater than -15 ppm/K or the difference is greater than +15 ppm compared with the CTE of the carrier layer and the CTE of the substrate layer. /K.

For a substrate with a carrier formed of a carrier layer and a substrate layer, even when the curl suppression layer is present between the carrier layer and the substrate layer, it is particularly made into a fourth glass substrate equivalent to the so-called glass substrate. In the case of relatively large laminates after the generation (680 mm×880 mm to 730 mm×920 mm), the effect of suppressing warpage can be sufficiently obtained. In addition, the presence of the curl suppression layer can increase the degree of freedom in design of the base material layer. Furthermore, the foreign matter adhering to the carrier layer is not easily mixed into the base material layer. In addition, the surface condition of the carrier layer is unlikely to affect the substrate layer, so a cheap polyimide film or the like can be selected, which can increase the design freedom of the carrier layer.

[Form 2] The polyimide resin laminate of form 2 has a base layer that is peelably bonded on one side of the carrier layer, and further has a curl suppression layer on the opposite side of the carrier layer. The CTE is less than or greater than any one of the CTE of the substrate layer and the curl suppression layer.

That is, the carrier layer is located between the base layer and the curl suppression layer. With this structure, it is preferable from the viewpoint of suppressing warpage. In addition, for example, the CTE of the carrier layer is preferably 10 ppm/K to 70 ppm/K.

The substrate layer becomes a transparent substrate instead of glass, and is a transparent substrate that supports the functional layer after the carrier layer is peeled off and removed after a functional layer such as an ITO film is formed on it and the RTR process is completed. Therefore, the total light transmittance of the substrate layer is preferably 80% or more, and more preferably 90% or more. In view of the required characteristics of thinning, weight reduction, and flexibility, the thickness of the substrate layer is as thin as possible within a range that does not impair processability, and is preferably 50 μm or less, and more preferably 5 μm to 25 μm. The CTE of the substrate layer is preferably 1 ppm/K to 80 ppm/K.

In addition, the glass transition temperature (Tg) is preferably 300°C or higher, more preferably 300°C to 450°C, due to the requirement of heat resistance applicable to the high temperature process of RTR. Since it is used as a resin substrate instead of glass, the elastic modulus of the substrate layer is preferably 2 GPa to 15 GPa, for example.

On the opposite side of the carrier layer, there is a curl suppressing layer containing a polyimide resin. From the viewpoint of adapting to the RTR process, the curl suppression layer is formed on the opposite side of the substrate layer in order to suppress the warpage of the substrate layer with the carrier, and the ITO film is formed on the carrier layer through the substrate layer. After waiting for the functional layer and completing the RTR process, when the carrier layer is peeled off and removed, it is removed together with the carrier layer. Therefore, in order to try to suppress warpage (curling) in the RTR process, the thickness or thermal expansion coefficient is selected. Therefore, the thickness of the curl suppression layer is preferably 50 μm or less, and more preferably 6 μm to 30 μm. In addition, the glass transition temperature (Tg) is preferably 300°C or higher, more preferably 300°C to 450°C, due to the requirement of heat resistance applicable to the high temperature process of RTR.

The CTE of the curl suppression layer is preferably similar to the CTE of the substrate layer, and it is preferably selected in a manner that eliminates the difference in CTE between the carrier layer and the substrate layer. Therefore, the difference in CTE from the substrate layer is within ±40 ppm/K, preferably within ±15 ppm/K. For example, the CTE of the curl suppression layer is preferably 1 ppm/K to 90 ppm/K.

For a substrate with a carrier formed of a carrier layer and a substrate layer, even when the curl suppression layer is present on the side opposite to the substrate, the fourth generation equivalent to the so-called glass substrate is specially made In the case of relatively large laminates (680 mm×880 mm to 730 mm×920 mm) and later, the effect of suppressing warpage can be sufficiently obtained. In addition, the presence of the curl suppression layer can increase the degree of freedom in design of the base material layer.

Hereinafter, the common content in the form 1 and form 2 will be described in detail.

The polyimide resin used as the curl suppressing layer is not particularly limited as long as it satisfies the above-mentioned characteristics. For example, it may be formed by polyimide having a structural unit represented by the following general formula (1). Preferably, it is a polyimide containing 50 mol% or more of a structural unit represented by the following general formula (1).

（1）[化1]

(1)

Here, X in the general formula (1) is an aromatic group or an alicyclic group, and is a tetravalent organic group having one or more aromatic rings or alicyclic rings, and R is a substituent having 1 to 6 carbons. Among them, suitable specific examples of raw materials used to form the group X include: pyromellitic dianhydride (PMDA), naphthalene-2,3,6,7-tetracarboxylic dianhydride (Naphthalene tetracarboxylic dianhydride) dianhydride, NTCDA), 3,3',4,4'-biphenyl tetracarboxylic dianhydride (BPDA), etc. In addition, suitable specific examples of R include -CH ₃ , -CF ₃ and the like.

Among them, if R is -CF ₃ , the releasability at the interface with the base layer can be improved, and these layers can be easily separated.

In addition, the structural unit may be contained in addition to the structural unit represented by the general formula (1), and it is suitable that the structural unit may be contained at a maximum of less than 50 mol%. Examples of the structural unit using common acid anhydrides and diamines are mentioned. Among them, the acid anhydrides that can be suitably used are pyromellitic dianhydride (PMDA), naphthalene-2,3,6,7-tetracarboxylic dianhydride (NTCDA), 3,3',4,4'-biphenyltetracarboxylic acid dianhydride Formic acid dianhydride (BPDA), cyclohexane tetracarboxylic dianhydride, phenylene bis (trimellitic acid monoester anhydride), 4,4'-oxybisphthalic dianhydride, benzophenone-3, 4,3',4'-tetracarboxylic dianhydride, diphenylsulfonium-3,4,3',4'-tetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 4,4 '-(2,2'-hexafluoroisopropylene) bisphthalic dianhydride, etc. On the other hand, diamines include meta-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminodiphenyl ether, 1,3-bis(4-aminobenzene Oxy)benzene, 4,4'-diaminodiphenyl sulfide, 2,2-bis(4-aminobenzyloxyphenyl)propane, bis[4-(4-aminophenoxy)benzene Group] chrysanthemum, 4,4'-diaminobenzaniline, 9,9-bis(4-aminophenyl)sulfonate, etc.

Generally, when the thermal expansion coefficient of polyimide becomes small, transparency decreases, and retardation in the thickness direction (retardation due to a difference in birefringence) increases. Therefore, it is not suitable for the following situations: after the RTR process is completed, the substrate layer separated from the carrier layer is used as a resin substrate of, for example, a display device, or used as a gas barrier film or a touch panel substrate. In contrast, in the present invention, the presence of the curl suppression layer on the opposite side allows the use of a base material layer having a larger thermal expansion coefficient than the carrier layer.

（2）The polyimide forming the base layer can be appropriately selected according to the use of the polyimide resin laminate. Among them, in the case of flexible resin substrates used in display devices such as liquid crystal display devices, organic EL display devices, electronic paper, color filters, touch panels, etc., the following general formula can be mentioned The polyimide of the structural unit represented by (2) preferably contains 50 mol% or more of the polyimide of the structural unit represented by the general formula (2). In addition, with regard to the structural units that can be contained in addition to the structural unit represented by the general formula (2) (it is suitable that the structural unit can be contained at a maximum of less than 50 mol%), as long as the transparency is not impaired, there may be mentioned and The same structural unit described in the general formula (1). Suitable anhydrides that can be used are pyromellitic dianhydride (PMDA), naphthalene-2,3,6,7-tetracarboxylic dianhydride (NTCDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride Anhydride (BPDA), cyclohexanetetracarboxylic dianhydride, phenylene bis(trimellitic acid monoester anhydride), 4,4'-oxydiphthalic dianhydride, benzophenone-3,4, 3',4'-tetracarboxylic dianhydride, diphenyl sulfide-3,4,3',4'-tetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 4,4'- (2,2'-hexafluoroisopropylene) bisphthalic dianhydride, etc. On the other hand, the diamine is m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminodiphenyl ether, 1,3-bis(4-aminobenzene Oxy)benzene, 4,4'-diaminodiphenyl sulfide, 2,2-bis(4-aminobenzyloxyphenyl)propane, bis[4-(4-aminophenoxy)benzene Group] chrysanthemum, 4,4'-diaminobenzaniline, 9,9-bis(4-aminophenyl)sulfonate, etc. [化2]

(2)

、

、

、

、

、

、

（3）   其中，從獲得440 nm～780 nm的波長範圍內的500 nm下的透過率為80%以上，且厚度方向的延遲為200 nm以下的聚醯亞胺樹脂作為基材層的觀點來看，更優選以下的任一個。 [化4]

、

、

In the general formula (2), Y is an aromatic or alicyclic tetravalent organic group, preferably any group represented by the following formula (3). [化3]

,

,

,

,

,

,

(3) Among them, from the viewpoint of obtaining a polyimide resin having a transmittance of 80% or more at 500 nm in the wavelength range of 440 nm to 780 nm and a retardation in the thickness direction of 200 nm or less as a base layer Obviously, any of the following is more preferable. [化4]

,

,

（4）The most suitable is a polyimide resin represented by the following formula (4). [化5]

(4)

The polyimide resin used as the carrier layer is not particularly limited as long as it satisfies the above-mentioned characteristics. For example, as a generally available polyimide resin, Kapton (Toray DuPont ( Toray-Dupont), Upilex (manufactured by Ube Industries Co., Ltd.), Apical (manufactured by Kaneka), or have a similar structure to these polyimide resins The commercially available polyimide of, can also be obtained by synthesizing diamine and acid dianhydride as described in detail below.

The various polyimides mentioned above are obtained by imidizing polyimine precursors (hereinafter also referred to as "polyamide acid"). The resin solution of polyimide acid can be obtained by using essentially It is obtained by reacting isomolar diamine as a raw material with acid dianhydride in an organic solvent. Specifically, it can be obtained, for example, by dissolving diamine in an organic polar solvent such as N,N-dimethylacetamide under nitrogen flow, adding tetracarboxylic dianhydride, and reacting at room temperature for about 5 hours . Here, the weight average molecular weight (Mw) of the polyamide acid is preferably about 10,000 to 300,000 from the viewpoint of uniformity of the film thickness at the time of coating or the mechanical strength of the obtained polyimide. The suitable molecular weight range of the polyimide resin is the same molecular weight range as that of the polyimide acid.

The base material layer and the curl suppression layer of the present invention are preferably obtained separately by a so-called casting method, which is to coat a resin solution of a polyimide or a polyimide precursor, dry it, and heat it. deal with. That is, when obtaining the polyimide resin laminate of the present invention, it is suitable to apply a resin solution of polyimide or a polyimide precursor to one or both sides of the carrier layer, dry, and heat-treat. Thereby, a base material layer and a curl suppression layer can be formed. For example, it is preferable to perform preheating treatment at 90°C to 130°C for about 5 minutes to 30 minutes for drying, etc., and then to perform imidization at 130°C to 360°C for 10 minutes to 240 minutes. High temperature heat treatment around.

The polyimide resin laminate obtained in this way can be separated at the interface between the substrate layer and the layer (carrier layer or curl suppression layer) in contact with the substrate layer. However, in order to facilitate the separation at the interface of these layers For separation, it is preferable that the substrate layer is formed of a fluorine-containing polyimide having a fluorine atom in the polyimide structure. By using this fluorine-containing polyimide, the peel strength of the substrate layer and the layer in contact with the substrate layer can be suitably 1 N/m to 200 N/m, more suitably 1 N/m ~100 N/m, so it has separability to the extent that it can be easily peeled off by hand, for example. In addition, the separation surface of the substrate layer directly maintains the surface roughness obtained by the casting method (usually the surface roughness Ra=1 nm to 80 nm), so it does not adversely affect the visibility of the display device.

In the present invention, for the polyimide resin laminate formed by laminating different materials, the warpage deformation (warpage amount) can be calculated by calculation based on the following idea, and the optimization of the polyimide resin laminate can be realized. That is, based on the simple material mechanics calculation based on the idea of Citation 4, the influence of the dead weight is calculated by the three-dimensional material mechanics calculation, and the warpage deformation (warpage amount) is added to obtain the final warpage amount. The finite element method is used as the calculation method, that is, the final warpage deformation in the state of thermal deformation and self-weight balance is discretized using a shell element, and the calculation is performed by a computer in a numerical calculation method ( Refer to Figure 3).

As described above, the polyimide resin laminate of the present invention can be suitably used to obtain a display device having a functional member on a base layer. That is, after forming a predetermined functional layer on the base layer, it is sufficient to separate at the interface between the curl suppression layer and the base layer, or at the interface between the base layer and the carrier layer. Here, the carrier layer functions as a base when the display portion is formed on the base layer side, ensuring the handleability and dimensional stability of the base layer during the manufacturing process of the display portion, but is finally removed and does not constitute a display device. Similarly, the curl suppression layer is separated together with the carrier layer, and similarly, it is finally removed without constituting a display device, even if the transparency is poor. By using such a polyimide resin laminate, a predetermined functional layer can be reliably formed on the base layer with good accuracy, and a thin, lightweight, and flexible display device can be obtained.

There are no particular restrictions on the functional layer formed on the base layer. For example, in the case of an organic EL display device, organic EL elements including TFTs, electrodes, and light-emitting layers are typically equivalent to the display portion. In addition, in the case of a liquid crystal display device, the functional layer is a TFT, a driving circuit, a color filter, etc. as necessary. In addition to these, various display devices such as electronic paper or micro-electro-mechanical system (Micro-Electro-Mechanical System, MEMS) displays are used as various functional layers previously formed on glass substrates and project predetermined images (animations or pictures). The parts necessary for the image are equivalent to the display section. Among them, for example, an annealing step of about 400° C. is generally required when forming a TFT. However, the polyimide resin laminate of the present invention has heat resistance that can withstand such an annealing step. [Example]

Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples. In addition, the present invention is not limited by these contents.

1. Various physical properties and performance test methods [Peel strength]

Regarding the peeling strength between the base layer-(curl suppression layer)-carrier layer, the laminate was processed into a short strip with a width of 1 mm to 10 mm and a length of 10 mm to 25 mm, using Toyo Seiki Co., Ltd. A tensile testing machine (Strograph-M1) peeled off the carrier layer in the 180° direction, and measured the peel strength. In addition, the case where the peel strength is strong and it is difficult to peel is regarded as "unpeelable". [Transmittance]

A 20 μm thick substrate layer was cut out in a 5 cm square, and the transmittance of 380 nm to 780 nm was measured using a Haze Meter NDH-5000 manufactured by Nippon Denshoku Industry Co., Ltd. [Ra]

The base material layer, the carrier layer, and the curl suppression layer were individually cut out in a 3 cm square, and their Ra was measured using an atomic force microscope (AFM) manufactured by Bruker AXS. [CTE]

Regarding the CTE of the substrate layer, carrier layer, and curl suppression layer, each layer was cut out in a 3 mm×15 mm square, and a thermomechanical analysis (TMA) device manufactured by Seiko Instruments was used while applying The tensile test is carried out on the load side of 5.0 g at a certain heating rate (10°C/min) in the temperature range of 30°C to 260°C, based on the elongation of the polyimide film relative to the temperature at 100°C to 250°C Measure CTE (×10 ^-6 /K). [Warpage]

A square sample with a side of 100 mm was cut out from the laminated film with a cutter knife, and the humidity was adjusted at 23°C and 50% for 24 hours, and then placed on a fixed plate. The four corners were measured with a vernier caliper. The average value of the lift height is regarded as warpage (curl).

2. Synthesis of polyamide acid (polyimide precursor) solution The raw materials used in the following synthesis examples or examples are shown below.

[Aromatic diamino compound] ·4,4'-Diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB) ·2,2'-Dimethyl-4,4'- Diaminobiphenyl (m-TB) ·1,3-bis(4-aminophenoxy)benzene (TPE-R) ·2,2-bis[4-(4-aminophenoxy)benzene Base] Propane (BAPP) · 1,4-Phenylene diamine (PPD)

[Anhydride of aromatic tetracarboxylic acid] ·Pyromellitic anhydride (PMDA) ·2,2-bis(3,4-dehydrated dicarboxyphenyl)hexafluoropropane (6FDA) ·2,3,2',3' -Biphenyltetracarboxylic dianhydride (BPDA)

[Solvent] ·N,N-Dimethylacetamide (DMAc) Synthesis Example 1

Under nitrogen flow, TFMB (9.4 g, 0.03 mol) was added to 127.5 g of solvent DMAc in a 300 ml separable flask while stirring and heated, and dissolved at 50°C. Then add 6FDA (13.09 g, 0.03 mol). The molar ratio of diamine and acid anhydride is substantially 1:1. Then, the solution was continuously stirred at room temperature for 3 hours to perform polymerization reaction, and 200 g of pale yellow viscous polyamide varnish A was obtained. In addition, the polyimide varnish A is cured under heating conditions described below, thereby obtaining a polyimide resin A.

Synthesis Example 2 Under nitrogen flow, 10.2 g of m-TB and 1.6 g of TPE-R were added to 170 g of solvent DMAc at a molar ratio of 90:10 in a 300 ml separable flask while stirring. Heat up and dissolve at 50°C. Then, 9.2 g of PMDA and 3.1 g of BPDA were added at a molar ratio of 90:10. The molar ratio of diamine and acid anhydride is substantially 1:1. Then, the solution was continuously stirred at room temperature for 3 hours to perform polymerization reaction, and 200 g of pale white viscous polyamide varnish B was obtained. In addition, this polyimide varnish B is cured under heating conditions described below, thereby obtaining a polyimide resin B.

Synthesis Example 3 In a 300 ml separable flask while stirring, TFMB (12.6 g, 0.04 mol) was added to 127.5 g of solvent DMAc, heated, and dissolved at 50°C under nitrogen flow. Then, 6FDA (2.2 g, 0.005 mol) and PMDA (7.7 g, 0.035 mol) were added at a molar ratio of 12.5:87.5. The molar ratio of diamine and acid anhydride is substantially 1:1. Then, the solution was continuously stirred at room temperature for 3 hours to perform polymerization reaction, and 150 g of pale white viscous polyamide varnish C was obtained. In addition, this polyimide varnish C is cured under heating conditions described below, thereby obtaining a polyimide resin C.

Synthesis Example 4 In a 300 ml separable flask while stirring, m-TB (14.4 g, 0.07 mol) was added to 170 g of solvent DMAc and heated to dissolve at 50°C under nitrogen flow. Then PMDA (13.6 g, 0.06 mol) and BPDA (2 g, 0.007 mol) were added at a molar ratio of 90:10. The molar ratio of diamine and acid anhydride is substantially 1:1. Then, the solution was continuously stirred at room temperature for 3 hours to perform polymerization reaction, and 200 g of pale white viscous polyamide varnish D was obtained. In addition, this polyimide varnish D is cured under heating conditions described below, whereby a polyimide resin D is obtained.

Synthesis Example 5 In a 300 ml separable flask, TPE-R (14.8 g, 0.05 mol) as a diamine was added to 170 g of solvent DMAc while stirring in a 300 ml separable flask and heated at 50°C under nitrogen flow. Down dissolve. Then, BPDA (15.2 g, 0.05 mol) was added as an acid anhydride. The molar ratio of diamine and acid anhydride is substantially 1:1. Then, the solution was continuously stirred at room temperature for 3 hours to perform polymerization reaction, and 200 g of pale white viscous polyamide varnish E was obtained. In addition, this polyimide varnish E is cured under heating conditions described later, whereby a polyimide resin E is obtained.

Synthesis Example 6 In a 300 ml separable flask, while stirring, add it to 170 g of solvent DMAc so that m-TB:TPE-R becomes 90:10 in molar ratio and heat , Dissolve at 50°C. Then it was added in a way that the mol ratio of PMDA:BPDA became 80:20. The molar ratio of diamine and acid anhydride is substantially 1:1. Then, the solution was continuously stirred at room temperature for 3 hours to perform polymerization reaction, and 200 g of pale white viscous polyamide F varnish was obtained. In addition, the polyimide F varnish is cured under heating conditions described below, thereby obtaining a polyimide resin F.

Synthesis Example 7 Under nitrogen flow, TFMB (16.93 g) was added to the solvent DMAc (170 g) and dissolved in a 300 ml separable flask while stirring. Then add PMDA (10.12 g) and 6FDA (2.95 g). Then, the solution was continuously stirred at room temperature for 6 hours to carry out a polymerization reaction, and 200 g of a pale yellow viscous polyamide H varnish was obtained. In addition, this polyimide H varnish is cured under heating conditions described below, whereby polyimide resin H is obtained.

Synthesis Example 8 Under nitrogen flow, BAPP (19.45 g) was added to the solvent DMAc (170 g) and dissolved in a 300 ml separable flask while stirring. Then PMDA (9.85 g) and BPDA (0.70 g) were added. Then, the solution was continuously stirred at room temperature for 6 hours to carry out a polymerization reaction, and 200 g of a pale yellow viscous polyamide I varnish was obtained. In addition, this polyimide I varnish is cured under heating conditions described below, thereby obtaining a polyimide resin I.

Synthesis Example 9 In a 300 ml separable flask, 4,4'-DAPE (8.97 g) was added to the solvent DMAc (170 g) and dissolved while stirring. Then add PMDA (8.95 g) and BPDA (12.08 g). Then, the solution was continuously stirred at room temperature for 6 hours to perform polymerization reaction, and 200 g of brown viscous polyamide J varnish was obtained. In addition, this polyimide J varnish is cured under heating conditions described below, whereby polyimide resin J is obtained.

Synthesis Example 10 Under nitrogen flow, 4,4'-DAPE (8.14 g) and PPD (4.40 g) were added to the solvent DMAc (170 g) and dissolved in a 300 ml separable flask while stirring. Then PMDA (17.45 g) was added. Then, the solution was continuously stirred at room temperature for 6 hours to perform polymerization reaction, and 200 g of brown viscous polyamide K varnish was obtained. In addition, this polyimide K varnish is cured under heating conditions described below, whereby polyimide resin K is obtained.

3. The formation of the coated polyimide (PI) layer uses a polyimide film (manufactured by Ningbo Jinshan, China, thickness = 0.75 mm, CTE = 45 ppm/K, hereinafter also referred to as "carrier film") As a carrier layer. As the carrier layer, two types of polyimide films were used. 1) Polyimide film 1: made in Ningbo Jinshan, China, thickness=0.75 mm, CTE=45 ppm/K, Ra=3 nm (hereinafter also referred to as carrier film 1) 2) Polyimide film 2: China Made by Rayitek, thickness = 0.75 mm, CTE = 45 ppm/K, Ra = 10 nm (hereinafter also referred to as carrier film 2)

Example 1 One side of the carrier film 1 (width 520 mm×length 500 m×thickness 75 μm) was rolled out at a speed of 2 m/min, and a mono pump was used to coat polyamide varnish B so that the film thickness became 45 μm. The film was passed through a continuous drying furnace composed of multiple furnaces, dried at 90°C for 2 minutes, and dried at 130°C for 1 minute. The film was further composed of multiple furnaces and the temperature was from the sample inlet side. The furnace was passed through a continuous furnace where the furnace on the outlet side was stepped up, and it was heated stepwise from 130°C to 400°C in a total of 25 minutes to produce polyamide with a curl suppression layer formed on the carrier film. Roll of amine resin B. Then, the roll was installed in the unwinding part of the same coating and drying device, and 100 μm of polyimide varnish A was coated on the polyimide resin C, and in a continuous drying furnace composed of multiple furnaces. Medium pass, drying at 90°C for 2 minutes, and drying at 130°C for 1 minute, and then in a continuous furnace composed of a plurality of furnaces, and the temperature gradually increases from the furnace on the inlet side of the sample to the furnace on the outlet side By stepwise heating from 130°C to 400°C in a total of 20 minutes, a polyimide resin A with a thickness of 10 μm was formed as a base layer, and a roll-shaped polyimide resin laminate (laminated Body 1).

Regarding the thickness of each layer of the laminate 1, the carrier layer was 75 μm, the curl suppression layer was 4.5 μm, and the base layer was 10 μm. The layer structure of the laminate 1 is schematically shown in FIG. 1.

Then, for the roll-shaped polyimide resin laminate, an RTR device equipped with a reeling section, a conveying roller, a process processing section, and a winding section was used to transfer the base material layer at a speed of 2 m/min. It is rolled up in the longitudinal direction, and one side is introduced into the process processing section installed in the vacuum chamber through the conveying roller. The sputtering method is used to continuously process the substrate layer with a thickness of 50 nm as a functional layer. The ITO film is formed and is rolled up in the form of a polyimide substrate film with a functional layer.

Furthermore, the polyimide substrate film with the functional layer was cut into a 370 mm×450 mm sheet shape, and the ITO film was formed in the XY direction in one direction (X direction) and the other direction (Y direction). Perform transparent circuit processing. At this time, the intersection of the Y circuit and the X circuit does not form a circuit.

Then, apply an over coating to the intersection of the XY circuit, heat it at 250°C to harden the overcoat, and use silver paste to bridge the overcoat to form an XY circuit, which is then formed on the ITO. The entire surface of the film side is coated with an overcoat agent, and an annealing treatment is performed at 270°C to perform curing of the overcoat agent and crystallization of ITO.

Finally, the cover glass (Optically Clear Adhesive, OCA) (transparent adhesive sheet) is attached to the surface of the cover glass on the ITO film side, and then the carrier film and the curl suppression layer are mechanically peeled off to form a base A touch panel substrate with a functional layer formed on the material layer.

Comparative Example 1 Without forming a curl suppression layer, polyimide resin A (thickness 10 μm) was formed on the carrier film as a base layer in the same manner as in Example 1, to obtain a polyimide resin laminate (laminate C1 ).

The laminated body C1 has a large warpage (curl), and when the ITO film is cut into a sheet in the manufacturing step of the touch panel, it cannot be aligned with the mask due to the warpage, and the transparent circuit processing in the XY direction cannot be processed. , Thus unable to make a touch panel.

Example 2 A carrier film (width 520 mm x length 500 m×thickness 75 μm) was rolled out at a speed of 2 m/min, and polyamide varnish E was coated with a Mono pump so that the film thickness became 100 μm. The film was passed through a continuous drying furnace composed of a plurality of furnaces, and dried at 90°C for 2 minutes and at 130°C for 1 minute to produce a polyimide resin having a curl suppression layer formed on the carrier film E's roll. Then, the roll was installed in the unwinding part of the same coating and drying device, 100 μm of polyimide varnish A was coated on the opposite side of the polyimide resin E, and then dried in a continuous drying system composed of multiple ovens. Pass through the furnace, dry at 90°C for 2 minutes, and dry at 130°C for 1 minute, and then in a continuous furnace composed of multiple furnaces and gradually increasing the temperature from the furnace on the inlet side of the sample to the furnace on the outlet side In the middle pass, stepwise heating from 130°C to 400°C for a total of 20 minutes to form a base layer of polyimide resin A with a thickness of 10 μm to obtain a roll-shaped polyimide resin laminate (Laminated body 2).

Regarding the thickness of each layer of the laminate 2, the carrier film was 75 μm, the curl suppression layer was 13 μm, and the base layer was 10 μm. The layer structure of the laminate 2 is schematically shown in FIG. 4.

Then, the laminated body 2 was produced by the same method as in Example 1 to produce a touch panel substrate in which a functional layer was formed on a base layer.

Example 3 Polyamide varnish C was used instead of polyamide varnish A as the substrate layer, and polyamide varnish D was used instead of polyamide varnish E as the curl suppression layer. In addition, the same as in the examples was used. 2 The same method was used to obtain a polyimide resin laminate (Laminate 3).

Regarding the thickness of each layer of the laminate 3, the carrier layer was 75 μm, the base layer was 12 μm, and the curl suppression layer was 13 μm.

On this laminated body 3, ITO and XY circuits were formed into a film by the same method as Example 1, and the touch panel was obtained.

Example 4 Polyimide film 2 was used as the carrier layer, and polyimide varnish F was used instead of polyimide varnish C as the curl suppression layer, except that the same method as in Example 1 was used to obtain polyimide Resin laminate (Laminate 4). Regarding the thickness of each layer of the laminate 4, the carrier layer was 75 μm, the base layer was 10 μm, and the curl suppression layer was 4 μm.

Example 5 Polyamide varnish H was used instead of polyamide varnish A as the substrate layer, and polyamide varnish E was used instead of polyamide varnish B as the curl suppression layer. In addition, the same as in the examples was used. 1 The same method was used to obtain a polyimide resin laminate (laminate 5).

Regarding the thickness of each layer of the laminate 5, the carrier layer was 75 μm, the base layer was 10 μm, and the curl suppression layer was 50 μm.

Example 6 A polyimide resin laminate (laminate 6) was obtained by the same method as Example 2 except for the thickness of the base layer and the curl suppression layer.

Regarding the thickness of each layer of the laminate 6, the carrier layer was 75 μm, the base layer was 10 μm, and the curl suppression layer was 13 μm.

Example 7 Polyamide varnish H was used instead of polyamide varnish A as the substrate layer, and polyamide varnish B was used instead of polyamide varnish E as the curl suppression layer. In addition, the same as in the examples was used. 2 The same method was used to obtain a polyimide resin laminate (Laminate 7).

Regarding the thickness of each layer of the laminate 7, the carrier layer was 75 μm, the base layer was 10 μm, and the curl suppression layer was 15 μm.

Comparative Example 2 A polyimide resin laminate (laminate C2) was obtained by the same method as in Example 1, except that polyamide varnish I was used instead of polyamide varnish B as the curl suppression layer.

Regarding the thickness of each layer of the laminate C2, the carrier layer was 75 μm, the base layer was 10 μm, and the curl suppression layer was 4 μm.

Comparative Example 3 A polyimide resin laminate (laminate C3) was obtained by the same method as in Example 2 except that polyamide varnish J was used instead of polyamide varnish E as the curl suppression layer.

Regarding the thickness of each layer of the laminate C3, the carrier layer was 75 μm, the base layer was 10 μm, and the curl suppression layer was 15 μm.

Comparative Example 4 A polyimide resin laminate (laminate C4) was obtained by the same method as in Example 1, except that polyamide varnish I was used instead of polyamide varnish B as the curl suppression layer.

Regarding the thickness of each layer of the laminate C4, the carrier layer was 75 μm, the base layer was 10 μm, and the curl suppression layer was 13 μm.

Comparative Example 5 The operation was performed in the same manner as in Example 1, except that polyamide H was used instead of polyamide A of Example 4, and polyamide K was used instead of polyamide E.

Polyamide varnish H was used instead of polyamide varnish A as the substrate layer, and polyamide varnish K was used instead of polyamide varnish B as the curl suppression layer. The same as in Example 1 was used, except that The method obtains a polyimide resin laminate (laminate C5).

Regarding the thickness of each layer of the laminate C5, the carrier layer was 75 μm, the base layer was 10 μm, and the curl suppression layer was 13 μm.

Table 1 shows the physical properties of the polyimide resin laminate obtained in the above Examples and Comparative Examples.

[Table 1]

1‧‧‧Functional layer 2‧‧‧Substrate layer 3‧‧‧Carrier layer 4‧‧‧Curl suppression layer 10‧‧‧Laminated body 11‧‧‧Sputtering device 12, 13‧‧‧Guide roller 14‧‧‧Unwind Roller 15‧‧‧Reel roll

Fig. 1 is a cross-sectional view showing the structure of each layer with a functional layer of the polyimide resin laminate of the present invention. Fig. 2 is a schematic diagram of an apparatus for forming a functional layer on a laminate. Fig. 3 is an analogy diagram showing a state where the polyimide laminate has warped. Fig. 4 is a cross-sectional view showing the structure of each layer with a functional layer of the polyimide resin laminate of the present invention.

1‧‧‧Functional layer

2‧‧‧Substrate layer

3‧‧‧Carrier layer

4‧‧‧Curl suppression layer

10‧‧‧Laminated body

Claims (14)

A polyimide resin laminate, which is a laminate of a curl suppression layer containing a polyimide resin, a carrier layer containing a polyimide resin, and a base layer containing a polyimide resin, and is characterized in : On one side of the base layer, the curl suppression layer and the carrier layer are peelably bonded, and the thermal expansion coefficient of the layer in contact with the base layer is less than or greater than the thermal expansion coefficient of other layers. One. The polyimide resin laminate according to the first item of the patent application, wherein the curl suppressing layer is provided on one side of the carrier layer, and further has the curl suppressing layer adhered to the curl suppressing layer in a peelable manner. In the substrate layer, the thermal expansion coefficient of the curl-inhibiting layer is less than or greater than any one of the thermal expansion coefficients of the carrier layer and the substrate layer. The polyimide resin laminate according to the second item of the scope of patent application, wherein the difference in thermal expansion coefficient between the base layer and the carrier layer is ±40 ppm/K or less. The polyimide resin laminate according to claim 2 wherein a functional layer is further formed on one side of the carrier layer with the curl suppression layer and the base layer interposed therebetween. The polyimide resin laminate according to claim 1, wherein the substrate layer is peelably bonded on one side of the carrier layer, and on the opposite side of the carrier layer With the curl suppression layer, the thermal expansion coefficient of the carrier layer is smaller than or greater than any one of the thermal expansion coefficients of the base layer and the curl suppression layer. The polyimide resin laminate as described in claim 5, wherein the difference in thermal expansion coefficient between the base layer and the curl suppression layer is ±40 ppm/K or less. The polyimide resin laminate according to claim 5, wherein a functional layer is further formed on one side of the carrier layer with the base layer interposed therebetween. The polyimide resin laminate as described in item 2 or item 5 of the scope of patent application, wherein the base layer has a total light transmittance of 80% or more and a thickness of 50 μm or less. The polyimide resin laminate according to item 2 or item 5 of the scope of patent application, wherein the glass transition temperature of the polyimide resin forming the substrate layer is 300° C. or higher. A polyimide film with a functional layer, which is characterized in that it uses the polyimide resin laminate as described in item 4 of the scope of the patent application, and is formed between the curl-inhibiting layer and the substrate layer. The interface is peeled off, and the carrier layer and the curl suppression layer are removed. A polyimide film with a functional layer, characterized in that it uses the polyimide resin laminate as described in item 7 of the scope of the patent application, at the interface between the carrier layer and the substrate layer It is formed by peeling off the carrier layer and the curl suppression layer. A method for manufacturing a polyimide resin laminate, which is a method for manufacturing the polyimide resin laminate as described in item 1 of the scope of the patent application, and is characterized in that: the carrier layer is coated by a casting method The curl suppression layer and the base material layer. The method for producing a polyimide resin laminate as described in claim 12, which hardens the curl-inhibiting layer and the base layer coated on the carrier layer integrally. The manufacturing method of the polyimide resin laminate as described in the 13th item of the scope of patent application, wherein the casting method is coating using a multilayer die or a continuous die.

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