Carrier material for producing resin film

Abstract

The present invention provides a carrier material on which a resin composition, serving as a raw material of a resin film, can be coated, the carrier material suppressing deformation of the resin film due to lifting even after high-temperature film formation and high-temperature heat treatment, and allowing easy separation between the carrier material and the resin film.　The present invention provides a carrier material for producing a resin film, the carrier material being characterized in that: a release resin coating film is formed on one surface or both surfaces of an aluminum foil base material; the release resin coating film has the weight loss rate of 1.5% or less at 200°C and 90.0% or more at 400°C according to thermogravimetry (TG); and the adhesion amount of the release resin coating film on the surface of the aluminum foil base material is between 0.01 g / m2 and 0.4 g / m2 both inclusive.

Description

Carrier material for resin film manufacturing

[0001] The present invention relates to a carrier material for producing a resin film.

[0002] In recent years, in the field of electronic substrates, there has been an increasing demand for higher frequency electrical signals and faster data transmission speeds. Accordingly, there is a demand for resin films used in electronic substrates to have better electrical properties.

[0003] Generally, methods for forming these resin films include a solution casting method in which a solution is applied to a base carrier material and high-temperature heat is applied to form a film, or a method in which a resin film produced by an extrusion method or the like is heat-treated while being thermocompressed onto a carrier material in order to remove residual stress and control the surface unevenness, thereby producing a resin film with the desired performance.

[0004] The above-mentioned resin film formation method is currently carried out by a batch system, which has low productivity and relatively high costs. Therefore, from the viewpoint of reducing costs, film formation by a roll-to-roll process is being considered.

[0005] Aluminum (Al) is lightweight and has excellent heat resistance, and when made into aluminum foil, it can be used in roll-to-roll processing. For this reason, it has attracted attention as a carrier material used in the production of the above-mentioned resin films by the roll-to-roll process.

[0006] The above-mentioned carrier material is required to have small dimensional changes due to the heat applied during the resin film formation, thermocompression bonding, or heat treatment process, to be able to easily peel the resin film and carrier material after the above process, and to be able to be transported roll-to-roll without wrinkles or undulations.

[0007] A release material for resin-based substrates has been proposed, which comprises aluminum foil and a resin coating film with high releasability, as a carrier material that prevents the resin-based substrate from adhering to a hot plate when heated and pressurized during the production of the resin-based substrate (see Patent Document 1).

[0008] Patent No. 5110613

[0009] However, the release material for resin-based substrates described in Patent Document 1 uses an epoxy resin for the resin coating. Therefore, when forming a resin film using raw materials such as liquid crystal polymers, modified polyimides, and fluorine-based resins, which have been studied in recent years, the temperatures during film formation or post-film formation heat treatment reach high temperatures of 250°C to 400°C, which the epoxy resin cannot withstand, resulting in decomposition and residue of the resin coating, making it difficult to peel the resin film from the release material. This causes problems such as partial lifting between the substrate and the resin coating, which can deform the formed resin film or transfer the resin coating to the resin film.

[0010] In view of the above circumstances, the present invention aims to provide a carrier material that can be coated with a resin composition, which is the raw material for a resin film, and that suppresses deformation of the resin film due to lifting even after high-temperature film formation and high-temperature heat treatment, and that allows the carrier material and the resin film to be easily peeled off.

[0011] As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by using a carrier material for producing a resin film in which a release resin coating film is formed on one or both sides of an aluminum foil base material, and the weight loss rate of the release resin coating film at 200 ° C. and 400 ° C. by thermogravimetry (TG) is within a specific range, and the adhesion amount of the release resin coating film on the surface of the aluminum foil base material is within a specific range, and have thus completed the present invention.

[0012] That is, the present invention relates to the following carrier material for producing a resin film: 1. A release resin coating film is formed on one or both sides of an aluminum foil substrate, the release resin coating film has a weight loss rate of 1.5% or less at 200°C and a weight loss rate of 90.0% or more at 400°C, as measured by thermogravimetry (TG), and the adhesion amount of the release resin coating film on the surface of the aluminum foil substrate is 0.01 g / m ２ 0.4g / m or more ２Item 2. A carrier material for producing resin films, characterized in that it is as follows: 2. The carrier material for producing resin films according to item 1, wherein the release resin coating contains at least one selected from the group consisting of acrylic resin and ethyl cellulose. 3. The carrier material for producing resin films according to item 1 or 2, wherein the aluminum foil base has a thickness of 5 μm or more and 300 μm or less. 4. The carrier material for producing resin films according to any one of items 1 to 3, wherein the aluminum foil base is an aluminum alloy foil containing 3.0 mass % or less manganese, 0.02 mass % or more and 1.75 mass % or less iron, 1.0 mass % or less silicon, 0.3 mass % or less copper, 0.3 mass % or less zinc, and 3.0 mass % or less magnesium, with the remainder being aluminum and unavoidable impurities.

[0013] The carrier material for producing resin films of the present invention can be coated with a resin composition that is the raw material for the resin film, and deformation of the resin film due to lifting is suppressed even after high-temperature film formation and high-temperature heat treatment, and the carrier material and the resin film can be easily peeled off.

[0014] 1 is a schematic diagram illustrating a method for producing a resin film by a solution casting method. FIG.

[0015] 1. Carrier material for producing resin films The carrier material for producing resin films of the present invention (hereinafter also simply referred to as "carrier material") comprises an aluminum foil substrate on one or both sides of which a release resin coating film is formed, the release resin coating film having a weight loss rate of 1.5% or less at 200°C and a weight loss rate of 90.0% or more at 400°C, as measured by thermogravimetry (TG), and an adhesion amount of the release resin coating film on the surface of the aluminum foil substrate of 0.01 g / m ２ 0.4g / m or more ２ The carrier material for resin film production is as follows. Since the carrier material of the present invention uses an aluminum foil substrate with excellent thermal conductivity, heat is efficiently transmitted and the productivity of resin film formation is improved. In addition, by using an aluminum foil substrate, static electricity generation is reduced, adhesion of foreign matter to the carrier material of the present invention is suppressed, and the inclusion of foreign matter in the produced resin film can be suppressed.

[0016] Furthermore, the carrier material of the present invention has a weight loss rate of 1.5% or less at 200°C by thermogravimetry (TG). Therefore, even if the raw material for the resin film to be formed is a material with a relatively high film formation initiation temperature, such as a liquid crystal polymer, modified polyimide, or fluororesin, decomposition of the release resin film is suppressed, and deformation of the resin film to be produced is suppressed.

[0017] Furthermore, the carrier material of the present invention has a weight loss rate of 90.0% or more at 400°C in thermogravimetry (TG) of the release resin coating film, so that the formed resin film can be easily peeled off from the carrier material, and transfer of the release resin coating film to the resin film is suppressed.

[0018] Furthermore, the carrier material of the present invention has a release resin coating film adhesion amount of 0.01 g / m ２ 0.4g / m or more ２ Since the above condition is met, the amount of resin forming the release resin coating film present on the surface of the surface protective layer of the aluminum foil substrate is small, and the amount of the release resin coating film vaporized by the heat during film formation is small, thereby suppressing peeling between the carrier material and the film-forming resin.

[0019] In other words, since the carrier material of the present invention has all of the above-mentioned configurations, it can be coated with a resin composition that is the raw material for the resin film, and deformation of the resin film due to lifting is suppressed even after high-temperature film formation and high-temperature heat treatment, and the carrier material and the resin film can be easily peeled off.

[0020] Hereinafter, each of the components constituting the carrier material for producing a resin film of the present invention will be described.

[0021] The carrier material of the present invention can be suitably used as a release material, a release film, or the like.

[0022] (Aluminum foil substrate) As the aluminum foil substrate, known aluminum foil can be used, and pure aluminum foil or aluminum alloy foil can be used. When using aluminum alloy foil, as a component, silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), titanium (Ti), vanadium (V), gallium (Ga), nickel (Ni) and boron (B) at least one alloy element can be added within the required range, or aluminum foil with the content of the alloy element limited can be used. Industrially, aluminum foil of material such as 1N30, 8079, 8021 specified by JIS can be used.

[0023] A preferred composition of the aluminum foil substrate will be described below.

[0024] [Manganese] The aluminum foil substrate may be an aluminum alloy foil containing 3.0% by mass or less of manganese. By containing manganese, the strength of the aluminum foil substrate is further improved. However, if the manganese content exceeds 3.0% by mass, the hardness of the aluminum foil substrate surface increases, but the rollability decreases, which may make it difficult to obtain an aluminum alloy foil as an aluminum foil substrate. For this reason, the manganese content is preferably 3.0% by mass or less, more preferably 1.5% by mass or less. The lower limit of the manganese content is not particularly limited and is usually about 0.00001% by mass. In order to make the manganese content less than 0.00001% by mass, it is necessary to further repeat the fractional crystallization method, which may significantly increase the manufacturing cost. For these reasons, the manganese content in the aluminum foil substrate is preferably 0.00001% by mass or more and 3.0% by mass or less.

[0025] [Iron] The aluminum foil substrate may be an aluminum alloy foil containing 0.02% by mass or more and 1.75% by mass or less of iron. By adding a certain amount of iron to the aluminum alloy foil, the ductility by rolling is further improved, manufacturing is facilitated, and the elongation of the aluminum foil substrate can be further improved. Since the lower the iron content, the lower the ductility of aluminum, the iron content is preferably 0.02% by mass or more. Furthermore, if the iron content exceeds 1.75% by mass, coarse Al-Fe-based intermetallic compounds are generated in the aluminum alloy, which may cause abnormalities such as pinholes during foil production. For these reasons, the iron content in the aluminum foil substrate is preferably 0.02% by mass or more and 1.75% by mass or less.

[0026] [Silicon] The aluminum foil substrate may be an aluminum alloy foil containing 1.0% by mass or less of silicon. When silicon is present in the aluminum foil substrate, the hardness of the aluminum itself can be further improved. The lower limit of the silicon content is not particularly limited, and is usually about 0.00001% by mass. From the above, the silicon content in the aluminum foil substrate is preferably 0.00001% by mass or more and 1.0% by mass or less.

[0027] [Copper] The aluminum foil substrate may be an aluminum alloy foil containing 0.3% by mass or less of copper. By including copper in the aluminum foil substrate, the aluminum foil substrate can be made stronger relatively easily. However, if the copper content is high, the rollability of the aluminum foil substrate may be reduced. The lower limit of the copper content is not particularly limited and is usually about 0.00001% by mass. In order to make the copper content less than 0.00001% by mass, it is necessary to further repeat the fractional crystallization method, which may significantly increase the manufacturing cost. From the above, the copper content in the aluminum foil substrate is preferably 0.00001% by mass or more and 0.3% by mass or less.

[0028] [Zinc] The aluminum foil substrate may be an aluminum alloy foil containing 0.3% by mass or less of zinc. If zinc is present in the aluminum alloy foil, the corrosion resistance of the aluminum alloy foil may be reduced. Therefore, the zinc content relative to 100% by mass of the aluminum foil substrate is preferably 0.3% by mass or less. The lower limit of the zinc content is not particularly limited and is usually about 0.00001% by mass. In order to make the zinc content less than 0.00001% by mass, it is necessary to repeat the three-layer electrolysis method, which may significantly increase the manufacturing cost. For these reasons, the zinc content in the aluminum foil substrate is preferably 0.00001% by mass or more and 0.3% by mass or less.

[0029] [Magnesium] The aluminum foil substrate may be an aluminum alloy foil containing 3.0% by mass or less of magnesium. Magnesium has a high solid solubility in aluminum, and its inclusion can further improve the strength of the aluminum alloy foil. If the magnesium content exceeds 3.0% by mass, the rolling extensibility may decrease, making it difficult to form into an aluminum foil substrate. Therefore, the magnesium content in 100% by mass of the aluminum foil substrate is preferably 3.0% by mass or less. The lower limit of the magnesium content is not particularly limited and is usually about 0.00001% by mass. In order to reduce the magnesium content to less than 0.00001% by mass, repeated three-layer electrolysis may be required, which may significantly increase production costs. For these reasons, the magnesium content in the aluminum foil substrate is preferably 0.00001% by mass or more and 3.0% by mass or less, and more preferably 0.00001% by mass or more and 0.01% by mass or less.

[0030] [Other components] The aluminum foil substrate constituting the carrier material of the present invention may be an aluminum alloy foil containing, in addition to the above-mentioned metal elements, one or more elements selected from the group consisting of transition elements such as vanadium (V), titanium (Ti), zirconium (Zr), chromium (Cr), nickel (Ni), boron (B), gallium (Ga) and bismuth (Bi).The content of each of these elements is preferably 0.05% by mass or less in 100% by mass of the aluminum foil substrate.

[0031] The aluminum foil substrate constituting the carrier material of the present invention is preferably an aluminum alloy foil containing 3.0% by mass or less of manganese, 0.02% by mass or more and 1.75% by mass or less of iron, 1.0% by mass or less of silicon, 0.3% by mass or less of copper, 0.3% by mass or less of zinc, and 3.0% by mass or less of magnesium, with the balance being aluminum and inevitable impurities. Further, the aluminum foil substrate constituting the carrier material of the present invention is more preferably an aluminum alloy foil containing 0.00001% by mass or more and 3.0% by mass or less of manganese, 0.02% by mass or more and 1.75% by mass or less of iron, 0.00001% by mass or more and 1.0% by mass or less of silicon, 0.00001% by mass or more and 0.3% by mass or less of copper, 0.00001% by mass or more and 0.3% by mass or less of zinc, and 0.00001% by mass or more and 3.0% by mass or less of magnesium, with the balance being aluminum and inevitable impurities.

[0032] The aluminum foil substrate can be manufactured by a known method. For example, a molten aluminum or aluminum alloy having the above-mentioned predetermined composition is prepared and continuously cast. Then, the aluminum foil substrate can be obtained by hot rolling and cold rolling by continuous casting.

[0033] During the cold rolling process, intermediate annealing may be performed at a temperature in the range of 50 to 500° C., particularly 150 to 400° C. After the cold rolling process, annealing may be performed at a temperature in the range of 150 to 650° C., particularly 350 to 550° C. to form a soft foil.

[0034] The thickness of the aluminum foil substrate is not particularly limited. The thickness of the aluminum foil substrate is preferably 5 μm or more from the viewpoint of the strength of the aluminum foil substrate and ease of production. In addition, from the viewpoint of reducing the weight of the aluminum foil substrate, it is preferably 300 μm or less. In addition, from the viewpoint of the handleability when the carrier material of the present invention is used in a roll-to-roll process, the strength of the aluminum foil substrate, and ease of production, the thickness of the aluminum foil substrate is preferably 5 μm or more and 300 μm or less, more preferably 10 μm or more and 200 μm or less, and even more preferably 15 μm or more and 150 μm or less.

[0035] In order to set the thickness of the aluminum foil substrate within the above range, casting and rolling may be performed according to conventional methods. Furthermore, heat treatment may be performed appropriately during the manufacturing process. Specifically, an aluminum molten metal having a predetermined composition is prepared, and an ingot is manufactured by solidifying the aluminum molten metal. The obtained ingot may be subjected to a homogenization treatment at a temperature of about 400 to 630 ° C for about 1 to 20 hours. Next, the ingot is rolled to an aluminum foil substrate of a predetermined thickness by hot rolling and cold rolling. In addition, when a thin aluminum foil substrate is manufactured by continuous casting, an aluminum foil substrate of a desired thickness can also be obtained by cold rolling directly after continuous casting.

[0036] (Release resin coating film) In the carrier material of the present invention, a release resin coating film is formed on one or both sides of the aluminum foil substrate. The release resin coating film is formed on only one side or both sides of the carrier material in accordance with the application and use form of the carrier material, and is usually formed on one side of the carrier material.

[0037] In the carrier material of the present invention, the release resin coating has a weight loss rate of 1.5% or less at 200°C as measured by thermogravimetry (TG). If the weight loss rate exceeds 1.5%, excessive thermal decomposition occurs during the formation of the resin film, causing the film to peel off from the carrier material or excessive gas generation, making it impossible to form a smooth and uniform resin film. The weight loss rate is preferably 1.3% or less, more preferably 1.0% or less. The lower limit of the weight loss rate is not particularly limited and may be 0.1%, 0.3%, or 0.5%.

[0038] In this specification, the weight loss rate at 200°C is measured by the method described in the Examples.

[0039] In the carrier material of the present invention, the release resin coating has a weight loss rate of 90.0% or more at 400°C as measured by thermogravimetry (TG). If the weight loss rate is less than 90.0%, the carrier material cannot be easily released from the resin film after the resin film formation is completed, or even if it can be released, the release resin coating will be transferred to the resin film. The weight loss rate is preferably 95% or more, more preferably 99% or more. The upper limit of the weight loss rate is not particularly limited, and may be 99.9% or 99.5%.

[0040] In this specification, the weight loss rate at 400°C is measured by the method described in the Examples.

[0041] In the carrier material of the present invention, the release resin coating preferably has a weight loss rate of 1.0% or less at 200° C. and 99% or more at 400° C., as measured by thermogravimetry (TG). By keeping the weight loss rate within the above ranges, deformation of the resin film due to lifting after high-temperature film formation and high-temperature heat treatment is further suppressed, and the carrier material and the resin film can be more easily peeled off.

[0042] In the carrier material of the present invention, the amount of the release resin coating film on the surface of the aluminum foil substrate is 0.01 g / m ２ 0.4g / m or more ２ The deposition amount is 0.01 g / m or less. ２ If the adhesion amount is less than 0.4 g / m, it becomes difficult to easily release the carrier material after forming the resin film. This is thought to be because the amount of the release resin coating film present on the surface of the aluminum foil substrate is small, so the amount of the release resin coating film vaporized by the heat during film formation is small, and the driving force for peeling between the carrier material and the resin film is small. ２ If the adhesion amount exceeds 0.01 g / m, the resin film will peel off from the carrier material during film formation, or excessive gas will be generated, making it impossible to form a smooth and uniform resin film. This is thought to be because the release resin coating film is excessively vaporized during resin film formation, causing the formed resin film to deform due to the generated gas, or the formed resin film will peel off completely during film formation. ２ 0.35g / m or more２ The following is preferred:

[0043] In this specification, the amount of the release resin coating film on the surface of the aluminum foil substrate is measured by the measurement method described in the Examples.

[0044] The resin component for forming the release resin coating film is not particularly limited as long as the release resin coating film can exhibit the above-mentioned weight loss rate and adhesion amount, but examples thereof include acrylic resin, cellulose resin, fluorine-based resin such as polytetrafluoroethylene (PTFE), polyimide (PI) resin, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (OPP), etc. Among these, acrylic resin and ethyl cellulose are preferred, that is, the release resin coating film preferably contains at least one selected from the group consisting of acrylic resin and ethyl cellulose.

[0045] The above resin components can be used alone or in combination of two or more.

[0046] The acrylic resin is preferably an acrylic resin mainly composed of a methacrylate polymer, and this acrylic resin begins to thermally decompose at 200° C. or higher and can be almost completely thermally decomposed by 400° C., and by containing this resin, the film can function more effectively as a release resin coating. Furthermore, ethyl cellulose begins to thermally decompose at 200° C. or higher and can be thermally decomposed by 90% or more by 400° C., and the film can function more effectively as a release resin coating.

[0047] The content of the resin component in the release resin coating film is preferably 70% by mass or more, more preferably 90% by mass or more, based on 100% by mass of the release resin coating film. When the lower limit of the resin component content is within the above range, deformation of the resin film due to lifting is further suppressed, and the carrier material and the resin film can be more easily peeled off. In addition, the upper limit of the resin component content is not particularly limited, and may be 100% by mass, 99% by mass, or 98% by mass.

[0048] The release resin coating may contain other additives in addition to the resin component, such as antioxidants, ultraviolet absorbers, antistatic agents, and antifoaming agents.

[0049] The thickness of the release resin coating film is not particularly limited, and is generally preferably about 0.005 to 0.5 μm, more preferably about 0.008 to 0.4 μm.

[0050] 2. Method of Using Carrier Material for Producing Resin Film The method of using the carrier material of the present invention will be described by taking as an example a method of producing a resin film, which is a type of resin-based substrate, by a solution casting method.

[0051] The solution casting method is a manufacturing method used to produce resin films that are difficult to produce by melt extrusion, i.e., resins that are prone to melt decomposition or have high melting points. Examples of resins that form such resin films include polyester, polyimide, triacetyl cellulose, diacetyl cellulose, polyvinyl chloride, polyvinyl alcohol, and polycarbonate. By producing a resin film using the solution casting method, the orientation of the polymer molecules in the resin film is suppressed, thereby suppressing the directionality of strength and optical properties. Furthermore, the resin film has high thickness accuracy and excellent properties such as smoothness, transparency, and gloss. Therefore, resin films produced by the solution casting method can be used for polarizing films, polarizing film protective films, phase films, and the like.

[0052] The solution casting method will be described using the drawings. FIG. 1 is a schematic diagram illustrating a manufacturing method for manufacturing a resin film by the solution casting method. In FIG. 1, a resin composition prepared by dissolving a resin in a solvent is poured from a hopper 21 onto the surface of a carrier material carried in by a plurality of carry-in rolls 22, on which the release resin coating film is formed, and adheres to the surface. Next, the carrier material with the adhered resin composition is carried into a heating means 23, such as an oven, by the carry-in rolls. Inside the heating means 23, the solvent of the resin solution cast on the carrier material 1 evaporates, producing a laminate in which a resin film is formed on the carrier material. Next, the laminate is sent out of the heating means by a plurality of carry-out rolls 24 and cooled. The cooled laminate is wound up by a wind-up roll 25. Next, the carrier material is peeled off from the wound laminate, producing a resin film 11.

[0053] According to the carrier material of the present invention described above, a resin composition, which is a raw material for a resin film, can be applied, and deformation of the resin film due to lifting is suppressed even after high-temperature film formation and high-temperature heat treatment, and the carrier material and the resin film can be easily peeled off. The technical fields to which the carrier material of the present invention can be applied are not limited, and it can be used, for example, in the manufacture and processing of printed circuit boards, multilayer wiring boards, FPCs, antenna coils, IC tag / IC card substrates, etc. The carrier material of the present invention can be suitably used in the above-mentioned fields as a release material, release film, etc.

[0054] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0055] (Preparation of Aluminum Foil Substrate) Aluminum alloys having the compositions shown in Table 1 below were cast to prepare aluminum foil substrates.

[0056]

[0057] Specifically, an ingot of an aluminum alloy having the composition shown in Table 1, produced by continuous casting at a cooling rate of 5 ° C. / sec, was prepared. The ingot was subjected to homogenization heat treatment at 530 ° C. for 5 hours in a heating furnace. Next, hot rolling was performed until the thickness reached approximately 6.5 mm to produce a hot-rolled material. The produced hot-rolled material was subjected to multiple cold rolling operations. Specifically, intermediate annealing was performed at 390 ° C. for 3 hours during cold rolling, and cold rolling was performed until the thickness reached 40 μm. Next, final annealing was performed at 300 ° C. for 3 hours to prepare an aluminum foil substrate.

[0058] (Formation of coating film such as release resin) The resin coating materials used in the examples and comparative examples are as follows: Acrylic resin: Marproof MH-0D041 manufactured by NOF Corporation Ethyl cellulose: Ethocel 300 manufactured by Nisshin Chemical Co., Ltd. Polyvinyl butyral: S-LEC BX-L manufactured by Sekisui Chemical Co., Ltd. Phenolic resin: PL-2243 manufactured by Gun-ei Chemical Co., Ltd. Epoxy resin: a mixture of bisphenol A type epoxy resin, methyl etherified melamine resin, and hydroxyl group-containing polyester-modified polydimethylsiloxane in a mass ratio of 100:45:1.5 Silica: a mixture of SP Clear HT manufactured by Ceramic Coat Co., Ltd. and hydroxyl group-containing polyester-modified polydimethylsiloxane in a mass ratio of 100:1 Edible oils and fats: Actor L01 manufactured by Riken Vitamin Co., Ltd.

[0059] The above-mentioned resins and the like were used in each example and comparative example as shown in Table 2 to produce a carrier material for resin film production. Specifically, a coating film of the type of release resin or the like shown in Table 2 was applied to one surface of the prepared aluminum foil substrate by gravure printing. The coating liquids of Examples 1 to 4 and Comparative Examples 1, 2, 6, and 7 were prepared by dissolving the solid resin that would become the coating film in ethyl lactate. In Comparative Examples 3 to 5, the coating film was already in a liquid state. During coating, the solution was appropriately diluted or the cell volume of the gravure plate was changed to adjust the desired adhesion amount. When diluting, the coating liquids of Examples 1 to 4 and Comparative Examples 1, 2, 6, and 7 were diluted with ethyl lactate. Comparative Example 3 was diluted with methyl ethyl ketone. Comparative Example 4 was diluted with isopropyl alcohol. Comparative Example 5 did not require dilution. After coating, the coating was dried at 160° C. for 1 minute to volatilize the solvent, forming a coating film of the release resin or the like on the aluminum foil substrate, thereby producing a carrier material for producing a resin film.

[0060] (Evaluation Method) The following evaluations were carried out for the Examples and Comparative Examples.

[0061] <Formation of Resin Film> A polyimide varnish (Spiceria TP003, manufactured by Somar Co., Ltd.) was applied to the surface of the coating film of the release resin or the like of the produced carrier material using an applicator with a gap of 100 μm, and dried under conditions of 200 ° C. for 10 minutes to volatilize the solvent component in the resin film coating liquid. Next, the coating film was baked by heating under conditions of 300 ° C. for 30 minutes.

[0062] Weight Loss Rate at 200°C The weight loss rate at 200°C of the coating film of the release resin or the like was measured by thermogravimetry (TG) using the following method. That is, the coating film of the release resin or the like was scraped off from the carrier material and sampled. Using the sampled coating film of the release resin or the like, the weight loss rate at 200°C was measured using a thermogravimetry analyzer (manufactured by Hitachi High-Tech Science Corporation, model number STA-7300) when the temperature was increased from 40°C to 750°C at a heating rate of 10°C / min in an air atmosphere.

[0063] Weight Loss Rate at 400°C The weight loss rate at 400°C of the coating film of the release resin or the like was measured by thermogravimetry (TG) using the following method. That is, the coating film of the release resin or the like was scraped off from the carrier material and sampled. Using the sampled coating film of the release resin or the like, the weight loss rate at 400°C was measured using a thermogravimetry analyzer (manufactured by Hitachi High-Tech Science Corporation, model number STA-7300) when the temperature was increased from 40°C to 750°C at a heating rate of 10°C / min in an air atmosphere.

[0064] Adhesion amount The adhesion amount of a coating film such as a release resin on the surface of an aluminum foil substrate was measured by the following measurement method. That is, a carrier material having a coating film such as a release resin laminated on the surface of an aluminum foil substrate was cut into a square of 100 mm square, and the mass was measured using a weighing balance (HR-250A manufactured by A&D Co., Ltd.). Next, the coating film such as a release resin was dissolved and removed with methyl ethyl ketone, and the mass was measured again using a weighing balance. The adhesion amount (g / m ) was calculated from the difference in mass. 2 ) was calculated.

[0065] Resin Coating Wettability When the polyimide varnish was applied with an applicator, it was visually observed whether the coating was uniform, and evaluated according to the following evaluation criteria: ◯: Uniform coating was possible ×: Coating unevenness such as repelling occurred

[0066] Film-forming ability The polyimide varnish was visually observed to determine whether it had formed a smooth resin film without deformation after baking, and was evaluated according to the following evaluation criteria: ◯: The polyimide varnish was in full contact with the carrier material for resin film formation, and no local deformation was observed ×: A lift of Φ1 mm or more occurred due to gas generation, or the resin film had completely peeled off from the carrier material for resin film formation

[0067] Peelability: A resin film formed on a carrier material for resin film formation was peeled upward at a 90-degree angle at 50 mm / min (see Figure 6 of JIS C6481), and the peel strength was measured. Evaluation was performed according to the following evaluation criteria: ◯: Peel strength is 200 g / cm or less; ×: Peel strength is more than 200 g / cm.

[0068] Presence or absence of transfer After releasing the resin film from the carrier material for resin film formation, the resin film surface was analyzed using Fourier transform infrared spectroscopy (NICOLET iS20 manufactured by Thermo Scientific) to determine whether components other than the polyimide of the resin film were detected. Evaluation was performed according to the following evaluation criteria. ◯: No detection peaks of coating components such as release resin were observed. ×: Detection peaks of coating components such as release resin were observed.

[0069] The results are shown in Table 2.

[0070]

[0071] In Comparative Examples 1 and 4, the weight loss rate of the release resin coating film at 400°C was small, so after film formation, it was difficult to peel off from the carrier material, and the release resin coating film was transferred to the peeled surface.

[0072] In Comparative Examples 2 and 3, the weight loss rate of the coating film of the release resin or the like at 200° C. was high and the weight loss rate of the coating film of the release resin or the like at 400° C. was low, so that lifting occurred due to gas generation during film formation. In addition, peeling occurred, and a uniform resin film could not be formed.

[0073] In Comparative Example 5, coating unevenness occurred during coating of the film-forming resin, etc., and coating was not possible.

[0074] In Comparative Example 6, the amount of acrylic resin attached was small, making it difficult to peel off the resin film after it was formed.

[0075] In Comparative Example 7, the amount of acrylic resin attached was so large that gas was generated during heating for baking film formation, causing the resin film to lift, and a uniform resin film could not be formed.

[0076] 1. Carrier material for producing resin film 11. Resin film 21. Hopper 22. Carrying-in roll 23. Heating means 24. Carrying-out roll 25. Winding roll

Claims

1. A release resin coating film is formed on one or both sides of an aluminum foil substrate. The release resin coating film has a weight loss rate of 1.5% or less at 200 °C and a weight loss rate of 90.0% or more at 400 °C in thermogravimetric measurement (TG). The adhesion amount of the release resin coating film on the surface of the aluminum foil substrate is 0.01 g / m ２ or more and 0.4 g / m ２ or less. A carrier material for resin film production, characterized by the above.

2. The carrier material for resin film production according to claim 1, wherein the release resin coating film contains at least one selected from the group consisting of an acrylic resin and ethyl cellulose.

3. The carrier material for resin film production according to claim 1, wherein the thickness of the aluminum foil substrate is 5 μm or more and 300 μm or less.

4. The carrier material for resin film production according to any one of claims 1 to 3, wherein the aluminum foil substrate contains 3.0% by mass or less of manganese, 0.02% by mass or more and 1.75% by mass or less of iron, 1.0% by mass or less of silicon, 0.3% by mass or less of copper, 0.3% by mass or less of zinc, and 3.0% by mass or less of magnesium, and the balance is an aluminum alloy foil composed of aluminum and inevitable impurities.

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