Resin film with release sheet

Abstract

In view of this case, the present invention addresses the problem of providing a resin film which has good quality and good peelability from a release sheet, while suppressing the expansion of shrinkage even if a resin containing particles having a particle diameter sufficiently large with respect to the thickness of the resin film is disposed on one surface of the release sheet. A resin film with a release sheet, in which a resin composition containing the following components [A]-[D] is disposed on one surface of a release sheet, the resin film with a release sheet contains 10-30 mass% of particles [D] in the resin composition, and the resin film with a release sheet has the following characteristic (I). [A] an epoxy resin, [B] a thermoplastic resin, [C] a curing agent, [D] particles containing large-particle-diameter particles having a particle diameter exceeding 2A with respect to the average resin thickness (A) of the resin film. (I) The peeling resistance [X] (mN / 20 mm) of the resin-coated surface in the release sheet and the complex viscosity [Y] (MPa.s) of the resin composition at 25 DEG C are present in a region satisfying the following formulae (1)-(1)-(1)-4. 500 < = X < = 4000 (1)-1 0.01 < = Y < = 2.1 (1)-2 # imgabs 0 # imgabs 1 #

Description

Technical Field

[0001] The present invention relates to a resin film with a release sheet containing large-diameter particles. Background Art

[0002] In the past, resin films with release sheets obtained by thinly stretching resin (hereinafter referred to as resin films) have been widely used in electronic components, automobiles, adhesives, medical components, etc. due to their ease of operation and processability. With the recent miniaturization / thinning and lightweighting of components, the resin films used are also required to be thinner. When the resin film is formed, the quality of the resin film is reduced due to the formation of pinholes, which are extremely small holes, on the surface coated with the resin, and the shrinkage (hereinafter referred to as shrinkage) that occurs when the resin on the surface repel each other and form holes or depressions. Patent document 1 describes an adhesive film for semiconductors. In order to provide a resin film with good thin film coating properties and easy peeling properties and suppressing pinholes and shrinkage, a scheme is proposed to specify the surface energy of the substrate coated with the resin. The film thickness of the above-mentioned film is specified to be less than 10 μm. On the other hand, the use of a particulate filler with a maximum particle size of less than 25 μm is described.

[0003] Furthermore, with the recent development of multifunctional products and the fierce competition for product differentiation due to new functions and added value, it has become a new important issue to make the resin film itself functional.

[0004] Various technologies have been proposed to address these challenges. Broadly speaking, these include methods that process the resin film surface through processes such as sputtering and surface treatment, and methods that incorporate functional fillers into the resin itself. The latter, in particular, allows for a wide range of functions to be imparted to the resin film, as the type and size of the filler used yields varying functionality.

[0005] In addition, if there is a filler in the resin film, in the case of a filler containing a volatile component, it is easy to produce gaps, bulges, and peeling, and it becomes difficult to apply the resin evenly and with high quality. In addition, when the filler is in the form of particles, generally speaking, a filler with a particle size smaller than the resin thickness is often mixed. However, when the resin film is laminated for the purpose of imparting functionality such as thermal conductivity, a granular filler with a particle size larger than the resin thickness is sometimes mixed. If such a granular filler with a large particle size is mixed, when or after the resin is arranged on the release sheet, it is easy to produce pinholes and shrinkage based on the filler, and the quality of the resin film deteriorates. In patent document 2, it is proposed to provide a resin film of excellent quality containing coarse particles with a particle size larger than the resin thickness, using a reverse roller coater method to specify the B / C ratio (the ratio of the B roller (coating roller) speed to the C roller (support roller) speed).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-162680

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2016-160367 Summary of the Invention

[0010] Problems to be solved by the invention

[0011] If a resin containing particles having a particle size larger than the thickness of the resin is used as the particles contained in the resin film, not only will the above-mentioned shrinkage occur when it is arranged on one side of the release sheet, but there is also a tendency for the shrinkage to increase over time, deteriorating the quality of the resin film. Therefore, it is necessary to increase the viscosity of the resin to suppress fluidity, or to change the surface properties of the release sheet to facilitate the retention of the resin. However, if the viscosity of the resin is increased to make it easier to retain on the release sheet, the releasability of the resin from the release sheet will deteriorate. In the invention described in Patent Document 1, although it is described that a particulate filler having both good thin film coating properties and good releasability from the substrate and a maximum diameter exceeding twice the film thickness can be used, a composition containing particles with a maximum diameter of less than twice the film thickness is considered to be a more preferred solution. No special problems arising when using particles with a particle size sufficiently large relative to the film thickness and their solutions have been found. Patent Document 2 discloses the use of particles containing coarse particles exceeding 2Aμm relative to the resin thickness Aμm of the resin film. However, Patent Document 2 does not describe or even hint at the aforementioned shrinkage issue caused by coarse particles. Furthermore, Patent Document 2 states that the amount of particles containing coarse particles used in a composition for obtaining a high-quality resin film is small, with the coarse particle content being considered to be 2% by mass or less of one of the two types of particles used. This suggests that the invention avoids compositions containing excessively high amounts of coarse particles, but does not disclose the technology required to obtain a high-quality resin film using a resin composition containing coarse particles exceeding the aforementioned amount.

[0012] That is, it cannot be said that the existing technical literature recognizes the issue of shrinkage that occurs specifically when containing particles with a particle size larger than the thickness of the resin film, and there is no specific disclosure on a method for suppressing it. As a result, it is difficult to obtain a resin film with suppressed expansion of shrinkage, good quality, and good releasability from a release sheet.

[0013] In view of such circumstances, the problem to be solved by the present invention is to provide a resin film that has good quality and good releasability from a release sheet while suppressing the expansion of shrinkage even when a resin containing particles having a particle size sufficiently large relative to the thickness of the resin film is arranged on one side of a release sheet.

[0014] Means for solving problems

[0015] The present invention for solving the above-mentioned problems includes the following configuration: Particles having a particle size exceeding twice the average resin thickness A of the resin composition disposed on one side of the release sheet, i.e., particles having a particle size exceeding 2A (2×A), are referred to as large-diameter particles in the present invention.

[0016] 1. A resin film with a release sheet, wherein a resin composition containing the following components [A] to [D] is disposed on one side of the release sheet.

[0017] The resin composition contains 10 to 30% by mass of particles [D].

[0018] The resin film with a release sheet has the following characteristics (I).

[0019] [A] Epoxy resin

[0020] [B] Thermoplastic resin

[0021] [C] Curing agent

[0022] [D] Particles containing large-diameter particles having a particle diameter exceeding 2 Å relative to the average resin thickness A of the resin film

[0023] (I) The peel resistance [X] (mN / 20 mm) of the resin-coated surface of the release sheet and the complex viscosity [Y] (MPa·s) of the resin composition at 25° C. exist in the region satisfying the following formulas (1)-1 to (1)-4.

[0024] 500≤X≤4000 (1)-1

[0025] 0.01≤Y≤2.1 (1)-2

[0026]

[0027] 2. The resin film with a release sheet according to 1 above, wherein the particles [D] have a particle size distribution in which the content of the large-size particles is 10 to 30% by number of the total amount of the particles [D].

[0028] 3. The resin film with a release sheet according to 1 or 2 above, wherein the particles [D] are inorganic particles.

[0029] 4. The resin film with a release sheet according to any one of 1 to 3 above, wherein the particles of [D] are spherical.

[0030] 5. The resin film with a release sheet according to any one of 1 to 4 above, wherein the average resin thickness A of the resin film is 50 μm or less.

[0031] 6. The resin film with a release sheet according to any one of 1 to 5 above, which has the following properties (II) and (III).

[0032] (II) The resin coverage of the resin film with the release sheet immediately after coating is 95% or more,

[0033] The expansion ratio of shrinkage on the resin film with a release sheet represented by the following formula (2) is 6 times or less

[0034]

[0035] (III) The release rate of the resin composition from the release sheet is 95% or more

[0036] Effects of the Invention

[0037] According to the present invention, a resin film can be obtained in which a resin containing a predetermined amount of large-diameter particles exceeding 2A relative to the average resin thickness A is arranged on one side of a release sheet. This resin film is a resin film with a release sheet in which expansion of shrinkage is suppressed, the quality is good, and the releasability from the release sheet is also good. DETAILED DESCRIPTION

[0038] The epoxy resin [A] used in the resin film with a release sheet of the present invention is not particularly limited and may be either liquid or solid. Examples thereof include amine-type epoxy resins, bisphenol-type epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, resorcinol-type epoxy resins, phenol aralkyl-type epoxy resins, naphthol-type epoxy resins, dicyclopentadiene-type epoxy resins, epoxy resins having a biphenyl skeleton, isocyanate-modified epoxy resins, tetraphenylethane-type epoxy resins, and triphenylmethane-type epoxy resins.

[0039] Among them, amine-type epoxy resins and bisphenol-type epoxy resins are preferably used because they have an excellent balance between heat resistance and adhesiveness. In addition, these epoxy resins can be self-cured by heating and can be mixed with a curing agent, a curing accelerator, etc.

[0040] As the amine type epoxy resin, a trifunctional or tetrafunctional amine type epoxy resin is preferably used, and examples thereof include tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, triglycidylaminocresol, tetraglycidylxylenediamine, and halogen- or alkynol-substituted or hydrogenated products thereof.

[0041] These epoxy resins may be used alone or in combination as appropriate. A combination of a glycidylamine epoxy resin and a bifunctional glycidylether epoxy resin is particularly preferred because they have both heat resistance and moisture resistance.

[0042] Bisphenol-type epoxy resins are bisphenol compounds in which two phenolic hydroxyl groups are glycidylated. Examples include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, and halogen-, alkyl-, and hydrogenated forms of these bisphenols. Furthermore, these bisphenols are not limited to monomers; high-molecular-weight forms having multiple repeating units can also be suitably used.

[0043] The thermoplastic resin [B] used in the resin film with a release sheet of the present invention is not particularly limited. When the epoxy resin [A] is liquid, it is dissolved in the epoxy resin during preparation of the resin composition, thereby forming the resin composition together with the epoxy resin. Specific compounds of the thermoplastic resin [B] preferably include polyethersulfone, polysulfone, polyimide, polyetherimide, polycarbonate, polyetherethersulfone, polyvinyl formal, and polymethyl methacrylate.

[0044] The curing agent [C] of the resin used in the resin film with a release sheet of the present invention can be any compound as long as it has an active group reactive with an epoxy group. Examples of curing agents include single or mixed aromatic amines, dicyandiamide, and dibasic acid dihydrazides. Among these, aromatic amines are preferred, and specific examples thereof include m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and m-xylylenediamine.

[0045] These curing agents may be used alone or in combination as appropriate. Aromatic amines are particularly preferred because they can impart heat resistance to cured resins.

[0046] The [D] particles used in the resin film with a release sheet of the present invention are large particles having a particle size exceeding 2 Å relative to the average resin thickness A of the resin film. However, the particles are at least partially insoluble in the epoxy resin composition. Hereinafter, large particles having a particle size exceeding 2 Å relative to the average resin thickness A of the resin film may also be referred to as [D] particles. Examples of these particles include metal particles, rubber particles, thermoplastic resin particles, and inorganic particles. Generally, particles that are insoluble in the epoxy resin composition and can exist as particles in the cured resin are used. Examples of the material include acrylic acid, polyamide, polyimide, polyaramid, polyester, polycarbonate, polyphenylene sulfide, polybenzimidazole, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, polyacetylene, polyaniline, polypyrrole, polythiophene, polyisothianaphthene, polyethylenedioxythiophene, carbon, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, tungsten trioxide, vanadium pentoxide, barium titanate, potassium titanate, and various metal particles. Furthermore, these particles may be composed of a combination of any of a variety of materials. Examples include particles in which a core of an inorganic or organic material is coated with a metal material.

[0047] In this embodiment, multiple types of particles may be used simultaneously, and a particulate filler other than the [D] particles and not including large-sized particles may be used. Furthermore, each particle component is evaluated separately to determine whether it contains large-sized particles.

[0048] The resin composition as a whole contains 10 to 30% by mass of [D] particles. The amount of particles contained in the resin composition is preferably 25% by mass or less. In order to prevent the deterioration of the quality of the resin film, the shape of the particles is preferably spherical. In the present invention, when 40 particles are examined under a microscope, particles with a roundness of 1.1 or less account for more than 90% and are considered to be spherical. The roundness can be calculated by dividing the maximum radius of the particle by the minimum radius in accordance with JIS B 0621:1984. The particles involved in the present invention include large-size particles. Whether they are large-size particles is determined by the relationship with the resin thickness on one side of the release sheet in the resin film. Particles with a particle diameter exceeding 2A (unit: μm, etc.) relative to the average resin thickness A (unit: μm, etc.) are called large-size particles. In the present invention, the functionality of the large-diameter particles can be exhibited even if the content of the large-diameter particles in the [D] particles is 1% or more of the total amount of the [D] particles in the particle size distribution expressed on a number basis. However, in order to achieve sufficient effects, the content is preferably 10% or more, and the upper limit is preferably 30% or less. The upper limit of the content of the large-diameter particles is more preferably 25% or less, and even more preferably 20% or less.

[0049] The content of large-diameter particles (>2A) can be determined from data on at least 2,000 particles observed by microscopic examination at any location on a resin film magnified 300 times. If the content of large-diameter particles of the particles of the present invention is less than 10% of the total amount of [D] particles, the functionality of the particles may not be fully achieved when the resin film is laminated. Furthermore, if the content of large-diameter particles exceeds 30% of the total amount of [D] particles, the probability of contact between particles in the resin film may increase, which may deteriorate the quality of the resin film.

[0050] The particle size used in determining the particle size distribution, i.e., the particle size of each particle counted in the present invention, is the average of the maximum and minimum diameters of each particle observable by microscopic examination, and the particle size distribution is calculated using particles having this average diameter of 1 μm or more. Furthermore, the particle density [D] is preferably 1.0 g / cm 3 Above and 2.0g / cm 3 .

[0051] In order to obtain particles having a predetermined particle size, classification may be performed using a dry classifier (for example, TTSP Separator (manufactured by Hosokawa Micron Co., Ltd.)) or the like, as needed.

[0052] Furthermore, the particles used in the present invention are preferably capable of being dispersed in a resin by a normal mixing operation.

[0053] The resin composition used for the resin film of the present invention may contain, in addition to the above components, one or more substances selected from liquid thermosetting resins other than epoxy resins, curing accelerators, flame retardants, and silane coupling agents as needed.

[0054] Next, characteristic (I) is described. The relationship between the peel resistance [X] of the resin-disposed surface of the release sheet according to the present invention and the complex viscosity [Y] of the resin composition at 25°C exists in the region satisfying the following formulas (1)-1 to (1)-4.

[0055] 500≤X≤4000 (1)-1

[0056] 0.01≤Y≤2.1 (1)-2

[0057]

[0058] Furthermore, it is more preferred that the relationship between the peel resistance [X] of the surface on which the resin is disposed in the release sheet according to the present invention and the complex viscosity [Y] of the resin composition at 25° C. exists in a region satisfying the following formulae (1)-1, (1)-2′, (1)-3, and (1)-4′.

[0059] 500≤X≤4000 (1)-1

[0060] 0.01≤Y≤1 (1)-2′

[0061]

[0062] The peel resistance [X] of the surface of the release sheet on which the resin is disposed is a value obtained by the following measurement. A rectangular release sheet with a width of 250 mm and a length of 90 mm is fixed on a flat surface, and an adhesive made of an acrylic emulsion is applied to the surface. The coating thickness is 125 μm in a wet state immediately after application. Immediately after application, the adhesive is sintered and dried by heating at 100°C for 120 seconds. Next, a PET film is attached to the adhesive-coated surface of the dried release sheet. For example, a 7.5 kg rubber roller is reciprocated once, and the attachment is performed using the weight of the rubber roller. Next, after standing in an atmosphere of 23°C and 50% RH for 30 minutes, a test piece with a width of 20 mm and a length of 250 mm was cut out. For this test piece, a 180° peeling was performed according to the method specified in JIS Z 0237:2009 "Adhesive Tape / Sheet Testing Methods" except that the peel speed was changed to 1000 mm / min. The simple average value of the force at this time was defined as the peel resistance.

[0063] In addition, the so-called complex viscosity [Y] of the resin composition at 25°C refers to the complex viscosity at 25°C obtained by measuring the complex viscosity at 25°C from the viscoelasticity curve obtained by simply heating from 10°C at a heating rate of 2°C / min using a dynamic viscoelasticity measuring device (for example, ARES-G2: manufactured by TA Instruments, etc.) using parallel plates at a frequency of 77.25 Hz and a plate spacing of 0.5 mm. In addition, each of the formulas (1) is a formula obtained from a Y-axis semi-logarithmic graph with peel resistance [X] as the X-axis, complex viscosity [Y] as the Y-axis, and the Y-axis as a logarithmic scale. In the formulas (1)-2, (1)-2', (1)-4, and (1)-4', the coefficient of the exponential part of the exponential function e represents the slope of the Y-axis semi-logarithmic graph shown in the above formula. The coefficient of the exponential part of such an exponential function e is sometimes expressed as follows using E representing a power of 10. For example, "-7E-04" is expressed as -0.0007, which represents the slope of the semi-logarithmic graph on the Y axis shown in the above formula.

[0064] As described above, the resin composition used in the present invention contains particles [D] as an essential component. Preferably, 75% or less of these particles, in a particle size distribution expressed on a number basis, have a particle size larger than the average resin thickness A of the resin disposed on one side of the release sheet. In this case, when the release sheet is lowered, a height difference is created between the resin above the particles and the resin not above the particles but to the sides thereof, which is susceptible to the expansion force of the resin composition. As a result, shrinkage is likely to occur and, in addition, is likely to increase over time. To suppress the generation and expansion of shrinkage, the release sheet's peel resistance [X] is preferably high to a certain extent. A low peel resistance [X] of the release sheet is considered preferable in terms of ease of peeling from the resin film. In the present invention, since large-sized particles are used, if the peel resistance [X] is too low, the force holding the resin composition on the release sheet decreases, the expansion force of the resin composition increases, and thus the generation of more shrinkage increases, the expansion of shrinkage due to the passage of time becomes faster, and the quality of the resin film deteriorates. Furthermore, the present invention has discovered that in order to suppress the expansion force of the resin composition and thereby inhibit the generation and expansion of shrinkage, it is preferable to have a relatively high complex viscosity [Y] of the resin composition. Considering conventional technical knowledge, the first consideration is to use a resin composition with a low complex viscosity [Y] in a composition containing particles having a large particle size to prevent the occurrence of tearing between the resins due to the aforementioned height difference. However, the present invention has discovered that if the complex viscosity [Y] of the resin composition is too low, the resin composition tends to flow, increasing the expansion force and thus facilitating the generation of shrinkage. This accelerates the expansion of shrinkage over time, and deteriorates the quality of the resin film.

[0065] Furthermore, the higher the adsorption force of the [D] particles on the resin composition, the higher their affinity for the resin composition, and the more they can suppress the generation / expansion of shrinkage. Therefore, the adsorption force of the [D] particles is preferably 0.3 mN / m or more and 17.8 mN / m or less, more preferably 0.5 mN / m or more and 10 mN / m or less, and even more preferably 1.0 mN / m or more and 5 mN / m or less. The above adsorption force is measured by applying an adhesive to the probe side of a Si cantilever of an AFM (e.g., a scanning probe microscope (SPM) manufactured by Bruker), attaching the particles and allowing them to stand for 1 hour to secure them, contacting them with a sapphire substrate washed with ethanol, setting the holding time to 0 seconds, and setting the load speed to 300 nm / s at room temperature and a humidity of 20% or more and 40% or less.

[0066] On the other hand, if the release sheet's peel resistance [X] is excessively increased, the resin's releasability from the release sheet deteriorates. Furthermore, if the resin composition's complex viscosity [Y] is excessively increased to a certain value or higher, the resin becomes hard, deteriorating workability when placed on the release sheet and also impairing the resin's releasability from the release sheet. Therefore, in order to achieve both high quality and releasability, and to obtain an excellent resin film, it is necessary to appropriately control the release sheet's peel resistance [X] and the resin composition's complex viscosity [Y].

[0067] The peel resistance [X] of the release sheet is specifically set to be 500mN / 20mm or more, thereby suppressing the expansion force of the resin composition and suppressing the expansion of the shrinkage of the resin. In addition, by making the peel resistance [X] of the release sheet 4000mN / 20mm or less, the peelability of the resin from the release sheet becomes good. On the other hand, the complex viscosity [Y] of the resin composition at 25°C is specifically set to be 0.01MPa·s or more, thereby suppressing the expansion force of the resin composition and suppressing the expansion of the shrinkage on the resin film, preferably 0.08MPa·s or more. In addition, by making the complex viscosity [Y] be 2.1MPa·s or less, the operability when configuring the release sheet can be well maintained. From this point of view, the complex viscosity [Y] is more preferably 1MPa·s or less.

[0068] In addition to the above conditions, the balance between the release sheet's peel resistance [X] and the resin composition's complex viscosity [Y] at 25°C is also important. For example, within the above ranges of peel resistance [X] and complex viscosity [Y], a combination of 500 mN / 20 mm peel resistance [X] and 0.01 MPa·s complex viscosity [Y] results in the release sheet being unable to fully suppress the resin composition's expansion force, causing shrinkage and deterioration in quality. On the other hand, within the above ranges of peel resistance [X] and complex viscosity [Y], a combination of 4000 mN / 20 mm peel resistance [X] and 2.1 MPa·s complex viscosity [Y] results in poor releasability of the resin from the release sheet. However, if it is possible to obtain a range where Y ≥ 0.14e in a Y-axis semi-logarithmic graph with the peel resistance [X] as the X-axis and the complex viscosity [Y] as the Y-axis, and the Y-axis as the logarithmic scale, in which the peel resistance [X] and the complex viscosity [Y] are each within the region where the above-mentioned ranges of each are specified, excluding the range where both the peel resistance [X] and the complex viscosity [Y] are small and the range where both the peel resistance [X] and the complex viscosity [Y] are large, -7E-04X (1) -3 and Y≤3.00e -7E-04X (1)-4 The combination of [X] and [Y] can fully obtain a resin film with good quality and good peelability. In addition, from this point of view, it is more preferable to obtain a resin film that satisfies Y≥0.14e -7E-04X (1) -3 and Y≤1.40e-7E-04X (1)-4 A combination of [X] and [Y].

[0069] The average resin thickness A of the resin film with a release sheet of the present invention is preferably 50 μm or less. This thickness is determined by, with the resin film coated on the release sheet, lowering the temperature to below the glass transition temperature of the resin to achieve a glassy state. The average thickness of the resin film at 10 randomly selected points is measured using a micrometer (e.g., Mitutoyo Coolant Proof Micrometer, MDC-25MX). This value is calculated as the difference between the average thickness of the resin film measured separately (N=10) and the average thickness of the release sheet measured previously (N=10). By setting the average resin thickness A to 50 μm or less, thin and lightweight components can be manufactured even when the resin films are laminated. The lower limit of the average resin thickness A is not particularly limited, but is preferably 5 μm or greater. That is, the large-diameter particles included in the [D] particles are preferably 10 μm or larger. Furthermore, the maximum particle size of the large-diameter particles is preferably 120 μm or smaller.

[0070] As characteristic (II), the resin film with a release sheet of the present invention preferably has a shrinkage expansion ratio of 95% or more immediately after coating, and a shrinkage expansion ratio of 6 times or less represented by the following formula (2).

[0071]

[0072] In the present invention, the resin coverage of the resin film with a release sheet can be determined as follows: the surface of the resin film is enlarged to 50 times the magnification from the resin film side and a microscopic examination is performed. In the microscopic examination range of the resin film, an arbitrarily selected 10 mm × 10 mm square range is set as the unit area, and the area of ​​the release sheet coated with the resin composition is measured, and the ratio of the area to the above-mentioned unit area is taken to determine the resin coverage.

[0073] The shrinkage expansion ratio can be determined as follows: a resin film obtained by applying the resin composition to a release sheet is examined microscopically at a magnification of 200 times. The ratio of the area of ​​the shrinkage region 24 hours after application to the area of ​​the shrinkage region immediately after application, when observing a randomly selected shrinkage region, can be calculated. This ratio can be expressed by the above formula (2). The average of the area ratios obtained by observing the shrinkage regions at 10 randomly selected points is used as the shrinkage expansion ratio.

[0074] The shrinkage expansion ratio is preferably 6 times or less. If it exceeds 6 times, uncoated areas will form when the resin film with a release sheet is attached to a substrate, causing defects and failing to achieve the required properties. The above expansion ratio is preferably 4 times or less, and more preferably 3 times or less.

[0075] Here, the parameters related to characteristic (II) can also be confirmed by using the same release sheet and resin composition as the resin film with a release sheet, applying the above-mentioned resin composition on the above-mentioned release sheet using a doctor blade coater, and measuring and confirming it by the above-mentioned method immediately after coating and 24 hours after coating.

[0076] In addition, as characteristic (III), the resin film with a release sheet of the present invention preferably has a peeling rate of the resin composition from the release sheet of 95% or more. The peeling rate of the resin composition from the release sheet is measured as follows. The resin film is cut into a strip with a width of 25 mm and a length of 300 mm as a test piece. Next, a 2 kg rubber roller is reciprocated once and an evaluation tape (for example, DunplonTape No.3201R, manufactured by Nitto Denko Corporation, etc.) having the same shape as the cut test piece and a width of 25 mm, a length of 300 mm and an adhesive force of 8.1 N / 25 mm is attached to the resin side of the above-mentioned test piece. A stainless steel support is attached to the surface of the test piece to which the evaluation tape is attached using a double-sided tape. Next, the support is mounted on a tensile testing machine, and the evaluation tape is peeled off at a tensile speed of 10,000 mm / min in an atmosphere of 25°C and 50% RH along a direction of an angle of 90° relative to the length direction of the test piece. The entire test piece after peeling is photographed and the image is binarized to measure the area of ​​the resin composition not coated with the release sheet. The area is divided by the area of ​​the entire test piece, and the resulting value is set as the peeling rate. As characteristic (III), the resin film with a release sheet according to the present invention preferably has a peeling rate of 95%, particularly preferably 98% or more. If the peeling rate is less than 95%, when the resin film with a release sheet is attached to a substrate and the release sheet is peeled off, an uncoated portion that becomes a defect may sometimes be generated.

[0077] Furthermore, in the present invention, it is preferable to possess both the above-mentioned characteristics (II) and (III).

[0078] The upper limit and lower limit of the numerical range described above can be arbitrarily combined.

[0079] Example

[0080] Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples.

[0081] 1. Raw materials

[0082] <[A] Epoxy resin>

[0083] Tetraglycidyldiaminodiphenylmethane, "Sumiepoxy (registered trademark)" ELM434 (manufactured by Sumitomo Chemical Co., Ltd.)

[0084] Bisphenol F-type liquid epoxy resin ("EPICLON (registered trademark)" 830, manufactured by DIC Corporation).

[0085] [B] Thermoplastic resin

[0086] Polyethersulfone, "Virantage (registered trademark)" VW-10700RFP (manufactured by Solvay).

[0087] [C] Curing agent

[0088] 3,3'-diaminodiphenylsulfone [3,3'-DAS] (manufactured by Mitsui Chemicals Fine Co., Ltd.).

[0089] <Particle>

[0090] [D] Inorganic particles

[0091] The average particle size was 32 μm, the median particle size on a volume basis was 40 μm, the adsorption force was 2.4 mN / m, and the density was 1.4 g / cm 3 Of the 40 particles examined under a microscope, 9.5% had a roundness of 1.1 or less.

[0092] <Particle fillers (excluding large-sized particles)>

[0093] Polyamide particles, "Orgasol (registered trademark) 1002D" (manufactured by Arkema Co., Ltd.), do not contain particles exceeding 54 μm.

[0094] <Release sheet>

[0095] In the release sheet, silicone was used as the release agent. The silicone composition, coating amount, drying after coating on release paper, heat treatment and other conditions were adjusted to obtain release paper having the peel resistance shown in Table 1.

[0096] 2. Evaluation Method

[0097] Unless otherwise specified, each evaluation was performed with n=1.

[0098] <Peel resistance>

[0099] A rectangular release sheet measuring 250 mm wide and 90 mm long was fixed to a flat surface, and an adhesive consisting of an acrylic emulsion was applied to the surface. The coating thickness was 125 μm in the wet state immediately after application. Immediately after application, the adhesive was heated at 100°C for 120 seconds to sinter and dry. A PET film was then attached to the adhesive-coated surface of the dried release sheet. This was accomplished by using the weight of a 7.5 kg rubber roller, which was moved back and forth once. Next, after standing for 30 minutes in an atmosphere of 23°C and 50% RH, a test piece with a width of 20 mm and a length of 250 mm was cut out. For this test piece, the peeling speed was changed to 1000 mm / min. In addition, a 180° peeling was performed according to the method specified in JIS Z 0237:2009 "Adhesive Tape / Adhesive Sheet Testing Methods (Adhesive Tape / Adhesive Sheet Testing Methods)". The simple average value of the force at this time was defined as the peel resistance.

[0100] Complex viscosity

[0101] It refers to the complex viscosity at 25°C obtained by reading the complex viscosity from the viscoelasticity curve obtained by using a dynamic viscoelasticity measuring apparatus (ARESG2: manufactured by TA Instruments) with parallel plates, simply heating from 10°C at a heating rate of 2°C / min, at a frequency of 77.25 Hz, a plate spacing of 0.5 mm, and a strain of 0.17%.

[0102] <Resin coverage of the resin film with a release sheet immediately after coating>

[0103] The surface of the resin film is enlarged to 50 times the magnification from the resin film side and microscopically inspected. Within the microscopic inspection range of the resin film with an arbitrarily selected 10 mm × 10 mm square area as the unit area, the area of ​​the release sheet coated with the resin composition is measured and the ratio of the area to the above-mentioned unit area is calculated.

[0104] Shrinkage expansion ratio on resin film with release sheet

[0105] A resin film obtained by coating a release sheet with the resin composition was examined under a microscope at a magnification of 200 times. The ratio of the area of ​​the shrunken region 24 hours after coating to the area of ​​the shrunken region immediately after coating, when observed at a fixed point at one arbitrarily selected region, was calculated using the following formula (2). The area ratios obtained for the shrunken regions at 10 arbitrarily selected points were averaged.

[0106]

[0107] <Release rate of resin composition from release sheet>

[0108] The resin film was cut into strips with a width of 25 mm and a length of 300 mm as test pieces. Next, a 2 kg rubber roller was reciprocated once to make a Dunplon Tape No.3201R (made by Nitto Denko Co., Ltd.) having an adhesive force of 8.1 N / 25 mm as an evaluation tape with a width of 25 mm and a length of 300 mm of the same shape as the cut test piece be attached to the resin side of the above test piece. A stainless steel support was attached to the surface of the test piece to which the evaluation tape was attached using a double-sided tape. Next, the support was installed in a tensile testing machine, and the evaluation tape was peeled off along the length direction of the test piece at a tensile speed of 10,000 mm / min in an atmosphere of 25 ° C and 50% RH. The entire test piece after peeling was photographed, and the image was binarized to measure the area of ​​the resin composition not covered with the release sheet, which was divided by the area of ​​the entire test piece, and the resulting value was set as the peeling rate.

[0109] 3. Preparation of resin film with release sheet

[0110] Using a knife coater, the resin composition was applied to one side of a release sheet to produce a resin film with a release sheet. The average resin thickness A was 27 μm. [D] The proportion of large-sized particles exceeding 2A (μm) (i.e., exceeding 54 μm) within the inorganic particles was 11.8%.

[0111] [Examples 1-7] The compounds having the compositions shown in Table 1 were mixed as raw materials using a kneader to obtain resin compositions. The resulting resin compositions were applied to one side of a release sheet to obtain resin films with release sheets. The release sheet's peel resistance [X], the resin composition's complex viscosity at 25°C [Y], the resin coverage of the resin film with the release sheet immediately after application, the shrinkage expansion ratio, and the release rate of the resin composition from the release sheet are shown in Table 1.

[0112] [Comparative Example 1] A resin film with a release sheet was obtained in the same manner as in Example 2 except that the release sheet used was the same as in Example 4 and the peel resistance [X] was set to be low as shown in Table 1. In Comparative Example 1, the complex viscosity [Y] did not satisfy Y ≥ 0.14e -7E-04X (1)-3. The resin coverage, the shrinkage expansion ratio, and the peeling rate of the resin composition from the release sheet were evaluated under the same conditions as in Examples 1 to 7, as shown in Table 1.

[0113] [Comparative Example 2] A resin film with a release sheet was obtained in the same manner as in Example 3 except that the release sheet used in Example 4 was the same as that in Example 4 and the peeling resistance [X] was set to be low as shown in Table 1. In Comparative Example 2, the complex viscosity [Y] did not satisfy Y ≥ 0.14e -7E-04X(1)-3. The resin coverage, the shrinkage expansion ratio, and the peeling rate of the resin composition from the release sheet were evaluated under the same conditions as in Examples 1 to 7, as shown in Table 1.

[0114] [Comparative Example 3] A resin film with a release sheet was obtained in the same manner as in Example 7 except that the same release sheet as in Example 7 was used and the mass fraction of the thermoplastic resin [B] was set to a lower value as shown in Table 1. In Comparative Example 3, the complex viscosity [Y] did not satisfy Y ≥ 0.14e -7E-04X (1)-3. The resin coverage, the shrinkage expansion ratio, and the peeling rate of the resin composition from the release sheet were evaluated under the same conditions as in Examples 1 to 7, as shown in Table 1.

[0115] [Table 1]

[0116]

[0117] INDUSTRIAL APPLICABILITY The present invention is suitable for use in components requiring thermal conductivity obtained by laminating resin films, but its scope of application is not limited thereto.

Claims

1. A resin film with a release sheet, wherein a resin composition containing the following components A to D is disposed on one side of the release sheet. The resin composition contains 10 to 30% by mass of particles of D. The resin film with a release sheet has the following characteristics (I), A epoxy resin BThermoplastic resin C curing agent D contains particles with a particle size exceeding 2A relative to the average resin thickness A of the resin film. (I) The peel resistance X of the resin-coated surface of the release sheet and the complex viscosity Y of the resin composition at 25°C exist in the range satisfying the following formulas (1)-1 to (1)-4, wherein the unit of X is mN / 20 mm and the unit of Y is MPa·s. 500≤X≤4000 (1)-1 0.01≤Y≤2.1 (1)-2 2 . The resin film with a release sheet according to claim 1 , wherein the D particles have a particle size distribution in which the content of the large-size particles is 10 to 30% by number of the total amount of the D particles. The resin film with a release sheet according to claim 1 or 2, wherein the D particles are inorganic particles. The resin film with a release sheet according to claim 1 or 2, wherein the D particles are spherical. The resin film with a release sheet according to claim 1 or 2, wherein an average resin thickness A of the resin film is 50 μm or less.

6. The resin film with a release sheet according to claim 1 or 2, which has the following characteristics (II) and (III): (II) The resin coverage of the resin film with the release sheet immediately after coating is 95% or more, The expansion ratio of shrinkage on the resin film with a release sheet represented by the following formula (2) is 6 times or less, (III) The release rate of the resin composition from the release sheet is 95% or more.

7. The resin film with a release sheet according to claim 3, which has the following characteristics (II) and (III): (II) The resin coverage of the resin film with the release sheet immediately after coating is 95% or more, The expansion ratio of shrinkage on the resin film with a release sheet represented by the following formula (2) is 6 times or less, (III) The release rate of the resin composition from the release sheet is 95% or more.

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