Release Film

Abstract

To provide a release film that gives a molding having a good appearance.SOLUTION: The inventive release film has viscoelastic spectra determined in dynamic viscoelasticity (DMA) measurement at a temperature rise rate of 5°C / min and a frequency of 1 Hz, satisfying (a) and (b) illustrated below: (a) a storage elastic modulus at 150°C is 50 MPa or more; and (b) (E'1-E'2)[MPa] / (100-25)[°C] is 5-60 where E'1[MPa] is a storage elastic modulus at 25°C and E'2[MPa] is a storage elastic modulus at 100°C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a release film. [Background technology]

[0002] Conventionally, various techniques have been developed in the field of release films. For example, in the field of semiconductor device manufacturing processes, it is known to manufacture a molded body by disposing a release film between a mold and a molding object, and resin-sealing a molding object on which electronic components such as semiconductor elements are mounted by a molding method such as transfer molding or compression molding (e.g., Patent Documents 1 and 2). By disposing a release film between the mold and the molding object, the molded body can be easily removed from the mold after resin sealing. In addition, a release film used when resin molding using such a mold is also generally called a mold molding release film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-151949 A [Patent Document 2] JP 2020-19264 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, wrinkles and distortions that occur in the release film may be transferred to the surface of molded articles obtained using conventional release films, and there was room for improvement in terms of obtaining molded articles with a higher level of appearance. [Means for solving the problem]

[0005] The present inventors have conducted extensive research into the causes of wrinkles and distortions occurring in release films and have found the following problems. Usually, a suction port for vacuum exhaust is provided around the cavity recess of the lower mold in order to vacuum-adhere the release film to the inner surface of the cavity recess. After arranging the release film so as to cover both the cavity recess and the suction port around it, the air between the release film and the cavity recess is sucked through the suction port and vacuum exhausted, so that the release film can be vacuum-adhered to the inner surface of the cavity recess. During this vacuum exhaust, the release film is also drawn into the suction port to some extent, but if the deformation amount of the release film is not sufficient, a part of the release film may be drawn into the suction port, causing the end of the release film near the suction port to stand up. As a result, a small gap is generated between the end of the raised release film and the lower mold, and suction is not performed sufficiently, so that the adhesion of the release film to the cavity recess is reduced, and it has been revealed that the release film is more likely to develop wrinkles. The upper die holds a molding object on which electronic components such as semiconductor elements are mounted. The molding object is clamped from above and below by the lower die, whose cavity recess is filled with a sealing resin material, and the upper die, to which the molding object is fixed, and compressed to form a resin mold. At this time, the base of the lower die rises, applying pressure to compress the sealing resin material. At this time, the depth of the cavity becomes shallow, so that a small gap is generated between the release film and the inner surface of the cavity recess. It has been revealed that this causes deformation of the release film, which causes distortion and wrinkles.

[0006] Therefore, the present inventors have further studied from the viewpoint of solving such problems, and as an index for controlling the properties of the release film, they have focused on the viscoelastic spectrum under a certain condition and devised new indices related to the storage modulus and its ratio, and the equilibrium modulus. Then, by controlling each of these indices, it has been found that the occurrence of wrinkles in the release film can be suppressed by obtaining sufficient elongation (deformation) against the stress at the time of mold fitting, while returning to the original shape against the elongation (elastic recovery), and thus the present invention has been completed. In addition, it has been found that by controlling such new indices, the occurrence of wrinkles and distortions in the release film can be effectively suppressed, not limited to the use in the above-mentioned manufacturing method.

[0007] According to the present invention, Provided is a release film, the viscoelasticity spectrum of which, as measured in dynamic viscoelasticity (DMA) measurement at a heating rate of 5°C / min and a frequency of 1 Hz, satisfies the following (a) and (b). (a) the storage modulus at 150°C is 50 MPa or more; (b) When the storage modulus at 25°C is E'1 [MPa] and the storage modulus at 100°C is E'2 [MPa], (E'1-E'2) [MPa] / (100-25) [°C] is 5 to 60.

[0008] Further, according to the present invention, There is provided a release film, the viscoelasticity spectrum of which, as measured in a dynamic viscoelasticity (DMA) measurement under conditions of a heating rate of 5° C. / min and a frequency of 1 Hz, satisfies the following (c): (c) It has an equilibrium elastic modulus at least in the range of 200°C or more and 250°C or less, and the equilibrium elastic modulus is 1.0 MPa or more. Effect of the Invention

[0009] According to the present invention, there is provided a release film which suppresses the occurrence of wrinkles and distortion in the release film and enables a molded article with a good appearance to be obtained. [Brief description of the drawings]

[0010] [Figure 1]1 is a cross-sectional view showing a schematic cross section of a release film according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a graph showing an example of the equilibrium elastic modulus of the release film of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In all drawings, similar components are given the same reference numerals, and explanations are omitted as appropriate. To avoid complexity, (i) when there are multiple identical components in the same drawing, only one of them is given a reference numeral, and not all of them are given a reference numeral, or (ii) especially in Figure 2 and subsequent figures, components similar to those in Figure 1 are not given a reference numeral again. All drawings are for explanatory purposes only. The shapes and dimensional ratios of each member in the drawings do not necessarily correspond to the actual articles.

[0012] In this specification, the expression "a to b" in the explanation of a numerical range means from a to b, unless otherwise specified. For example, "1 to 5% by mass" means "1% by mass to 5% by mass." In this specification, MD direction refers to the machine direction and indicates the direction in which the resin flows, and TD direction refers to the transverse direction and indicates the vertical direction.

[0013] <Release film> The release film of the present embodiment may have a single layer structure, or may have a multilayer structure including a release layer on at least one side of the release film, i.e., the release surface, and a base layer made of a material different from the release layer. A multilayer structure is preferable from the viewpoint of achieving a high level of both sufficient elongation and elastic recovery against elongation. Hereinafter, the release film will be described in detail using a multilayer structure as an example.

[0014] FIG. 1 is a cross-sectional view that typically shows a cross section of the release film of the present embodiment. As shown in FIG. 1, a release film 11 of the present embodiment includes a base layer 2 and a release layer 1 laminated on the base layer 2.

[0015] The release film 11 of this embodiment has a viscoelasticity spectrum measured in dynamic viscoelasticity (DMA) measurement at a temperature rise rate of 5° C. / min and a frequency of 1 Hz, which satisfies the following (a) and (b). (a) the storage modulus at 150°C is 50 MPa or more; (b) When the storage modulus at 25°C is E'1 [MPa] and the storage modulus at 100°C is E'2 [MPa], (E'1-E'2) [MPa] / (100-25) [°C] is 5 to 60.

[0016] Alternatively, the release film 11 of this embodiment has a viscoelasticity spectrum measured in dynamic viscoelasticity (DMA) measurement at a temperature rise rate of 5° C. / min and a frequency of 1 Hz, which satisfies the following (c). (c) It has an equilibrium elastic modulus at least in the range of 200° C. or more and 250° C. or less, and the equilibrium elastic modulus is 1 MPa or more.

[0017] This allows sufficient elongation while simultaneously providing shape recovery against elongation, and effectively suppresses the occurrence of wrinkles and distortion in the release film 11. Although the details of the reason for this are not clear, it is presumed as follows.

[0018] First, by setting the storage modulus of the release film 11 at 150°C to the lower limit or more according to the index (a), even when the release film 11 is exposed to high temperatures during use, it is assumed that the release film 11 maintains a moderate strength and obtains dimensional stability and shape recovery, so that wrinkles and distortions are unlikely to occur. In addition, by the index (b), it is assumed that the release film 11 can obtain a moderate elongation against stress while following the mold in the process of being placed in a mold and heated from the room temperature state before use. Then, by simultaneously controlling the indexes (a) and (b), it is possible to achieve a high level of balance between sufficient elongation and recovery from elongation, and as a result, it is believed that wrinkles and distortions that may occur during use of the release film can be effectively suppressed.

[0019] In addition, the equilibrium elastic modulus of (c) is intended to enable the release film 11 to maintain its shape even in the range of 200° C. to 250° C., and it is presumed that good dimensional stability is obtained by setting the equilibrium elastic modulus to the lower limit or more. That is, when the release film 11 of the present embodiment is heated, for example, as shown in FIG. 2, a flat portion is observed in the range of 200° C. to 250° C., while the storage elastic modulus E' decreases. In other words, in the heated state from before use of the release film 11 until the mold is in close contact with the mold, the release film 11 has appropriate elasticity and elongation, and the shape of the release film 11 is maintained even during the subsequent thermocompression bonding, so that shape recovery is obtained and a high level of balance between sufficient elongation and recovery from elongation can be achieved, which is considered to effectively suppress wrinkles and distortions that may occur during use of the release film. In addition, by having an equilibrium elastic modulus at 250°C or less, it becomes easier to improve releasability, and good dimensional stability and interlayer strength can also be easily obtained.

[0020] In the above (a), the storage modulus at 150° C. is 50 MPa or more, preferably 50 MPa to 500 MPa, and more preferably 100 MPa to 450 MPa. In the above (b), (E′1−E′2) [Pa] / (100−25) [° C.] is 5 to 60, and preferably 10 to 55.

[0021] In the above (c), the equilibrium elastic modulus in the range of 200° C. or more and 250° C. or less is 1.0 MPa or more, and preferably 2 MPa to 10 MPa.

[0022] It is further preferred that the release film 11 of the present embodiment has a viscoelasticity spectrum measured in dynamic viscoelasticity (DMA) measurement at a temperature rise rate of 5° C. / min and a frequency of 1 Hz, which satisfies the following condition (d). (d) The loss modulus / storage modulus (loss tangent) in the MD direction at 180° C. is 0.05 or more and 0.2 or less, and preferably 0.05 to 0.15. By setting the loss modulus / storage modulus (loss tangent) within the above numerical range, it is possible to maintain a good balance between elasticity and elongation. For example, even if there is a protrusion when the lower mold and the upper mold are mated, the release film 11 will be able to stretch partially but then recover its shape, and it is presumed that this makes it easier to suppress the occurrence of wrinkles and distortions in the entire release film 11.

[0023] In this embodiment, the dynamic mechanical properties (DMA) can be measured using a commercially available dynamic mechanical properties measuring device (for example, "DMS6100" manufactured by SII Corporation) under the following measurement conditions. (Measurement conditions) Frequency: 1Hz Temperature range: 20~260℃ Heating rate: 5℃ / min Test piece: Approximately 10 mm wide Test mode: Tensile

[0024] It is preferable that the release film 11 of the present embodiment further satisfies the following (e). (e) The release film has a 5% tensile strength (5% modulus) at 180° C. of 1 MPa or more and 5 MPa or less, preferably 1 to 4, and more preferably 1.5 to 3. It is presumed that the index (e) makes it easier to control the ability of release film 11 to return to its original shape when stretched.

[0025] The above indicators (a) to (e) can be achieved by appropriately selecting and combining known methods, such as the types and amounts of raw materials for the release layer 1, the method for preparing the raw materials, and the manufacturing method for the release film 11, and by using techniques different from conventional methods. Among these, for example, when silicone resin is selected as the raw material of the release layer 1, factors for setting the above indicators within the desired numerical range include appropriately controlling the type and compounding ratio of the silicone resin, the crosslinking density and crosslinking structure of the resin, and improving the compounding ratio of the inorganic filler and the dispersibility of the inorganic filler. In addition, by adjusting the curing conditions, temperature, and time for obtaining the release layer 1, the crosslinking density and crosslinking structure of the resin can be appropriately controlled, and the above-mentioned indexes can be set to the desired numerical range. In addition, for example, in the manufacturing process of the release film, when the film is sandwiched between substrates, it is also possible to change the surface roughness depending on the surface condition. In addition, it is effective to control the combination of materials for the release layer 1 and the substrate layer 2.

[0026] The thickness of the release film 11 is preferably 5 μm or more and 150 μm or less, more preferably 10 μm or more and 100 μm or less, and even more preferably 15 μm or more and 80 μm or less.

[0027] Hereinafter, each layer of the release film 11 of the present embodiment will be described.

[0028] [Release layer] The release layer 1 forms one side of the release film 11 and has a release surface 3 .

[0029] The thickness of the release layer 1 is preferably from 1 μm to 150 μm, more preferably from 2 μm to 100 μm, even more preferably from 5 μm to 50 μm, and even more preferably from 30 μm to 300 μm. By setting the thickness of the release layer 1 to the above lower limit or more, the rigidity of the release film 11 is increased, and it becomes easier to suppress excessive deformation and wrinkles. As a result, mold followability and dimensional stability are obtained. On the other hand, by setting the thickness of the release layer 1 to the above upper limit or less, the rigidity of the release film 11 can be controlled, and a good balance between mold followability and releasability can be achieved.

[0030] The release surface 3 of the release layer 1 is the surface that comes into contact with a sealing resin, which will be described later, when the release film 11 is used. The surface roughness Rz of the release surface 3 is preferably 0.05 to 10 μm, and more preferably 0.08 to 7 μm. By setting the surface roughness Rz of the release surface 3 to be equal to or greater than the above lower limit, a good balance between releasability and mold conformability during molding can be achieved. On the other hand, by setting the surface roughness Rz of the release surface 3 to be equal to or less than the above upper limit, good releasability can be achieved while maintaining mold conformability and dimensional stability.

[0031] The surface roughness of the release surface 3 can be controlled by known methods, such as transferring an embossed pattern to the film using an embossed roll during the production process of the release film, or by incorporating particles into the material of the release layer. The surface roughness Rz of the release layer 1 is measured in accordance with JIS B0601:2013.

[0032] The release layer 1 is composed of a first resin composition containing a resin. The resin contained in the first resin composition preferably contains one or more types selected from silicone resin, fluororesin, polyolefin resin, polyester resin, melamine resin, epoxy resin, and polyamide resin, and more preferably contains one or more types selected from silicone resin, fluororesin, melamine resin, epoxy resin, and polyolefin resin from the viewpoint of obtaining a release surface 3 with good releasability. Among them, silicone resin is more preferable from the viewpoint of achieving both deformation and recovery.

[0033] (Silicone resin) The silicone resin is not particularly limited, and may be, for example, a compound containing two or more siloxane bonds (-Si-O-), such as various known or commercially available siloxane-based polymers.

[0034] The silicone resin preferably contains one or two selected from, for example, vinyl group-containing organopolysiloxane (A) and organohydrogenpolysiloxane (B), which provides rubber-like properties such as silicone elasticity and compressibility, making it easier to obtain sufficient elongation of the release film and shape recovery against elongation.

[0035] <<Vinyl group-containing organopolysiloxane (A)>> The vinyl group-containing organopolysiloxane (A) can contain a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

[0036] The vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains vinyl groups, and these vinyl groups become crosslinking points during curing.

[0037] The vinyl group content of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but for example, it is preferable that the vinyl group content is 15 mol% or less and that the vinyl group content is 2 or more in the molecule. This optimizes the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1), and ensures the formation of a network with each component described below.

[0038] In this specification, the vinyl group content refers to the mol % of vinyl group-containing siloxane units when all units constituting the vinyl group-containing linear organopolysiloxane (A1) are taken as 100 mol %, where it is considered that there is one vinyl group per vinyl group-containing siloxane unit.

[0039] The degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is, for example, preferably within the range of about 1000 to 10000, and more preferably about 2000 to 5000. The degree of polymerization can be determined, for example, as the polystyrene-equivalent number average degree of polymerization (or number average molecular weight) measured by GPC (gel permeation chromatography) using chloroform as a developing solvent.

[0040] Furthermore, the specific gravity of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of about 0.9 to 1.1.

[0041] By using a vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and specific gravity within the above ranges, it is possible to improve the heat resistance, flame retardancy, chemical stability, etc. of the resulting silicone rubber.

[0042] The vinyl group-containing linear organopolysiloxane (A1) preferably has a structure represented by the following formula (1).

[0043] [ka]

[0044] In formula (1), R 1 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group consisting of a combination thereof, each having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, with a methyl group being preferred. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group, with a vinyl group being preferred. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0045] Also, R 2 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a hydrocarbon group consisting of a combination thereof, each having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0046] Also, R 3is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group consisting of a combination thereof. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group.

[0047] Furthermore, R in formula (1) 1 and R 2 Examples of the substituent of R include a methyl group and a vinyl group. 3 Examples of the substituent include a methyl group.

[0048] In addition, in formula (1), multiple R 1 are independent of each other and may be different or the same. 2 , and R 3 The same applies to.

[0049] Furthermore, m and n are the numbers of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by formula (1), where m is an integer of 0 to 2000 and n is an integer of 1000 to 10000. m is preferably 0 to 1000 and n is preferably 2000 to 5000.

[0050] A specific example of the structure of the vinyl-containing linear organopolysiloxane (A1) represented by formula (1) is that represented by the following formula (1-1).

[0051] [ka]

[0052] In formula (1-1), R 1 and R 2 are each independently a methyl group or a vinyl group, and at least one of them is a vinyl group.

[0053] The vinyl group-containing linear organopolysiloxane (A1) may contain a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more vinyl groups in the molecule and having a vinyl group content of 0.4 mol% or less. The vinyl group content of the first vinyl group-containing linear organopolysiloxane (A1-1) may be 0.1 mol% or less.

[0054] The vinyl group-containing linear organopolysiloxane (A1) may contain a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) having a vinyl group content of 0.5 to 15 mol %.

[0055] By combining the first vinyl group-containing linear organopolysiloxane (A1-1) and the second vinyl group-containing linear organopolysiloxane (A1-2) with a high vinyl group content as the raw rubber, which is the raw material of the silicone rubber, the vinyl groups can be unevenly distributed, and the crosslinking density can be more effectively formed in the crosslinked network of the silicone rubber. As a result, the tear strength of the release film can be more effectively increased, and the dimensional stability and transferability can be easily controlled.

[0056] Specifically, the vinyl group-containing linear organopolysiloxane (A1) may be, for example, a vinyl group-containing linear organopolysiloxane represented by the above formula (1-1), 1 is a vinyl group and / or R 2 a first vinyl group-containing linear organopolysiloxane (A1-1) having two or more units in the molecule each of which is a vinyl group and containing 0.4 mol % or less of a unit represented by R 1 is a vinyl group and / or R 2 It is preferable to use a second vinyl group-containing linear organopolysiloxane (A1-2) containing 0.5 to 15 mol % of units in which the vinyl group is present.

[0057] The first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol %, and the second vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol %.

[0058] Furthermore, when the first vinyl group-containing linear organopolysiloxane (A1-1) and the second vinyl group-containing linear organopolysiloxane (A1-2) are combined and blended, the ratio of (A1-1) to (A1-2) is not particularly limited, but for example, the weight ratio of (A1-1):(A1-2) is preferably 50:50 to 95:5, and more preferably 80:20 to 90:10.

[0059] The first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may each be used alone or in combination of two or more.

[0060] The vinyl group-containing organopolysiloxane (A) may also contain a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

[0061] <<Organohydrogenpolysiloxane (B)>> The organohydrogenpolysiloxane (B) is classified into a linear organohydrogenpolysiloxane (B1) having a linear structure and a branched organohydrogenpolysiloxane (B2) having a branched structure, and may contain either one or both of these.

[0062] The linear organohydrogenpolysiloxane (B1) has a linear structure and a structure in which hydrogen is directly bonded to Si (≡Si-H), and is a polymer that undergoes a hydrosilylation reaction with the vinyl groups of the vinyl group-containing organopolysiloxane (A) and also with the vinyl groups of the components contained in the raw materials of the release layer 1, thereby crosslinking these components.

[0063] The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited, but for example, the weight average molecular weight is preferably 20,000 or less, and more preferably 1,000 or more and 10,000 or less.

[0064] The weight average molecular weight of the linear organohydrogenpolysiloxane (B1) can be measured, for example, by polystyrene conversion in gel permeation chromatography (GPC) using chloroform as a developing solvent.

[0065] Furthermore, it is usually preferred that the linear organohydrogenpolysiloxane (B1) does not have a vinyl group, which can reliably prevent the crosslinking reaction from proceeding within the molecule of the linear organohydrogenpolysiloxane (B1).

[0066] As the linear organohydrogenpolysiloxane (B1) as described above, for example, one having a structure represented by the following formula (2) is preferably used.

[0067] [ka]

[0068] In formula (2), R 4 is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group combining these groups, or a hydride group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, etc., and among these, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group, etc. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0069] Also, R 5is a substituted or unsubstituted alkyl group, alkenyl group, aryl group, a hydrocarbon group combining these groups, or a hydride group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0070] In addition, in formula (2), multiple R 4 are independent of each other and may be different or the same. 5 The same applies to R. 4 and R 5 At least two of these are hydride groups.

[0071] Also, R 6 is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group combining these. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. 6 are independent of each other and may be different from each other or may be the same.

[0072] In addition, R in formula (2) 4 ,R 5 ,R 6 Examples of the substituent include a methyl group and a vinyl group, and from the viewpoint of preventing an intramolecular crosslinking reaction, a methyl group is preferred.

[0073] Furthermore, m and n are the numbers of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by formula (2), where m is an integer of 2 to 150 and n is an integer of 2 to 150. Preferably, m is an integer of 2 to 100 and n is an integer of 2 to 100.

[0074] The linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more kinds.

[0075] Since the branched organohydrogenpolysiloxane (B2) has a branched structure, it forms areas with high crosslink density, and is a component that greatly contributes to the formation of a sparsely-dense structure of crosslink density in the silicone rubber system. Also, like the linear organohydrogenpolysiloxane (B1), it has a structure in which hydrogen is directly bonded to Si (≡Si-H), and is a polymer that undergoes a hydrosilylation reaction with the vinyl groups of the vinyl group-containing organopolysiloxane (A) and the vinyl groups of the components contained in the raw materials of the release layer 1, crosslinking these components.

[0076] The specific gravity of the branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

[0077] Furthermore, it is usually preferred that the branched organohydrogenpolysiloxane (B2) does not have a vinyl group, which can reliably prevent the crosslinking reaction from proceeding within the molecule of the branched organohydrogenpolysiloxane (B2).

[0078] As the branched organohydrogenpolysiloxane (B2), one represented by the following average composition formula (c) is preferred.

[0079] Average composition formula (c) (H a (R 7 ) 3-a SiO 1 / 2 ) m (SiO 4 / 2 ) n (In formula (c), R 7 is a monovalent organic group, a is an integer ranging from 1 to 3, and m is H a (R 7 ) 3-a SiO 1 / 2 The number of units, n, is SiO 4 / 2 (the number of units)

[0080] In formula (c), R 7 is a monovalent organic group, preferably a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an aryl group, or a hydrocarbon group consisting of a combination thereof. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferred. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

[0081] In formula (c), a is the number of hydride groups (hydrogen atoms directly bonded to Si) and is an integer ranging from 1 to 3, and preferably 1.

[0082] In addition, in formula (c), m is H a (R 7 ) 3-a SiO 1 / 2 The number of units, n, is SiO 4 / 2 It is the number of units.

[0083] The branched organohydrogenpolysiloxane (B2) has a branched structure. The linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) differ in that their structures are linear or branched, and the number of alkyl groups R bonded to Si (R / Si) when the number of Si is 1 is in the range of 1.8 to 2.1 for the linear organohydrogenpolysiloxane (B1) and 0.8 to 1.7 for the branched organohydrogenpolysiloxane (B2).

[0084] Since the branched organohydrogenpolysiloxane (B2) has a branched structure, for example, when heated in a nitrogen atmosphere to 1000° C. at a heating rate of 10° C. / min, the amount of residue is 5% or more. In contrast, since the linear organohydrogenpolysiloxane (B1) is linear, the amount of residue after heating under the above conditions is almost zero.

[0085] Specific examples of the branched organohydrogenpolysiloxane (B2) include those having a structure represented by the following formula (3).

[0086] [ka]

[0087] In formula (3), R 7 R is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group combining these, or a hydrogen atom. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. 7 Examples of the substituent include a methyl group.

[0088] In addition, in formula (3), multiple R 7 are independent of each other and may be different from each other or may be the same.

[0089] In addition, in formula (3), "-O-Si≡" indicates that Si has a branched structure extending three-dimensionally.

[0090] The branched organohydrogenpolysiloxane (B2) may be used alone or in combination of two or more kinds.

[0091] In the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2), the amount of hydrogen atoms (hydride groups) directly bonded to Si is not particularly limited. However, in the release layer 1, the total amount of hydride groups in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) is preferably 0.5 to 5 mol, more preferably 1 to 3.5 mol, per mol of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1). This ensures that a crosslinked network is formed between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) and the vinyl group-containing linear organopolysiloxane (A1).

[0092] (Fluorine resin) Specific examples of the fluorine-based resin include polymers of monomers such as tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, and perfluoroalkyl vinyl ether, and copolymers of two or more kinds of monomers. These may be used alone or in combination of two or more kinds.

[0093] (Polyolefin resin) The polyolefin resin is a resin having a structural unit derived from α-olefin such as ethylene, propylene, butene, and known resins can be used. Specific examples of polyolefin resins include polyethylene (PE) such as low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and linear low density polyethylene (mLLPE); polypropylene (PP); polyvinyl alcohol (PVA); ethylene-vinyl acetate copolymer (EVA); ethylene-methyl acrylate copolymer (EMA); ethylene-acrylic acid copolymer (EAA); ethylene-methyl methacrylate copolymer (EMMA); ethylene-ethyl acrylate copolymer (EEA); ethylene-methacrylic acid copolymer (EMAA); ionomer resin; ethylene-vinyl alcohol copolymer (EVOH), and cyclic olefin resin (COP). These may be used alone or in combination of two or more.

[0094] (polyester resin) Specific examples of the polyester resin include polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), polytrimethylene terephthalate resin (PTT), polyhexamethylene terephthalate resin (PHT), and polyethylene naphthalate resin (PEN). These may be used alone or in combination of two or more.

[0095] (Epoxy resin) As the epoxy resin, any monomer, oligomer, or polymer having two or more epoxy groups in one molecule can be used regardless of its molecular weight or molecular structure. Specific examples of such epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene) bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene) bisphenol type epoxy resin), and bisphenol Z type epoxy resin (4,4'-cyclohexydiene bisphenol type epoxy resin); novolac type epoxy resins such as phenol novolac type epoxy resin, brominated phenol novolac type epoxy resin, cresol novolac type epoxy resin, tetraphenol group ethane type novolac type epoxy resin, and novolac type epoxy resin having a condensed ring aromatic hydrocarbon structure; biphenyl type epoxy resin; xylitol type epoxy resin; aralkyl-type epoxy resins such as naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalene-type epoxy resins, naphthalene diol-type epoxy resins, bifunctional to tetrafunctional epoxy-type naphthalene resins, binaphthyl-type epoxy resins, and naphthalene aralkyl-type epoxy resins; epoxy resins having a naphthalene skeleton such as naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalene diol-type epoxy resins, binaphthyl-type epoxy resins, and naphthalene aralkyl-type epoxy resins; anthracene-type epoxy resins; phenoxy-type epoxy resins; dicyclopentadiene-type epoxy resins; norbornene-type epoxy resins; adamantane-type epoxy resins; fluorene-type epoxy resins, phosphorus-containing epoxy resins, alicyclic epoxy resins, aliphatic linear epoxy resins, bisphenol A novolac-type epoxy resins, bixylenol-type epoxy resins, triphenolmethane-type epoxy resins, trihydroxyphenylmethane-type epoxy resins, tetraphenylolethane-type epoxy resins, and heterocyclic epoxy resins such as triglycidyl isocyanurate;It may contain one or more selected from glycidyl amines such as N,N,N',N'-tetraglycidyl meta-xylylene diamine, N,N,N',N'-tetraglycidyl bisaminomethylcyclohexane, and N,N-diglycidyl aniline, copolymers of glycidyl (meth)acrylate and compounds having an ethylenically unsaturated double bond, epoxy resins having a butadiene structure, diglycidyl ethers of bisphenols, diglycidyl ethers of naphthalenediol, and glycidyl ethers of phenols;

[0096] (Polyamide resin) Examples of the polyamide resin include aliphatic polyamides, aromatic polyamides, etc. Specific examples of the aliphatic polyamides include polyamide 6, polyamide 6,6, polyamide 6-6,6 copolymer, polyamide 11, polyamide 12, etc. Specific examples of the aromatic polyamides include polyamide 61, polyamide 66 / 6T, polyamide 6T / 6, polyamide 12 / 6T, etc.

[0097] (Melamine resin) The melamine resin can be obtained, for example, by polycondensing a melamine compound with formaldehyde under neutral or weakly alkaline conditions. Specific examples include alkylated melamine resins such as methylated melamine resins and butylated melamine resins, methylolated melamine resins, and alkyl etherified melamines.

[0098] [others] In addition to the above-mentioned resin, the first resin composition may contain other components within a range that does not impair the properties of the release film 11. The other components are not limited, but may include a solvent, an inorganic filler, a coupling agent, an antistatic agent, a leveling agent, a dispersant, a pigment, a dye, an antioxidant, a flame retardant, a thermal conductivity improver, etc. Representative components will be described below.

[0099] (solvent) The first resin composition may contain, for example, a solvent depending on the method for producing the release layer 1. When the first resin composition contains a solvent, the release layer 1 can be produced by dissolving the first resin composition in the solvent and applying the solution. The solvent is not limited, and specific examples thereof include aliphatic hydrocarbons such as water, pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane, decane, dodecane, and tetradecane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, xylene, trifluoromethylbenzene, and benzotrifluoride; ethers such as diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, 1,4-dioxane, 1,3-dioxane, and tetrahydrofuran; haloalkanes such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane; carboxylic acid amides such as N,N-dimethylformamide and N,N-dimethylacetamide; and sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide. These may be used alone or in combination of two or more.

[0100] (Inorganic filler) In this embodiment, the first resin composition may contain an inorganic filler, which can form fine irregularities on the surface of the release layer 1 and improve the releasability. The inorganic filler is not particularly limited, but may be one or more particles selected from the group consisting of diatomaceous earth, iron oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, magnesium carbonate, zinc carbonate, glass wool, mica, calcium carbonate, zinc oxide, alumina, crystalline silica, amorphous silica, fused silica, and zeolite. Among these, one or more particles selected from the group consisting of calcium carbonate, zinc oxide, alumina, crystalline silica, amorphous silica, fused silica, and zeolite are preferred. Furthermore, depending on the synthesis method of silica, fumed silica (flame-processed silica), fired silica, precipitated silica, and the like may be used. The inorganic fillers may be used alone or in combination of two or more kinds.

[0101] The inorganic filler has a specific surface area of, for example, 50 to 400 m2 as measured by the BET method. 2 / g, and 100 to 400m 2 It is more preferable that the molecular weight is / g. The average primary particle size of the inorganic filler is, for example, preferably from 1 to 100 nm, and more preferably from about 5 to 20 nm.

[0102] By using an inorganic filler having a specific surface area and average particle size within this range, the hardness and mechanical strength of the formed release layer 1 can be improved, and the balance between releasability, mold conformability, and dimensional stability can be easily improved.

[0103] (Silane coupling agent) The silane coupling agent can have a hydrolyzable group. The hydrolyzable group is hydrolyzed by water to become a hydroxyl group, and the hydroxyl group undergoes a dehydration condensation reaction with the hydroxyl group on the surface of the inorganic filler, thereby modifying the surface of the inorganic filler.

[0104] The silane coupling agent may contain a silane coupling agent having a hydrophobic group. This provides the surface of the inorganic filler with this hydrophobic group, so that the cohesive force of the inorganic filler in the first resin composition and thus in the release layer 1 is reduced (in the case of silica particles, the cohesion due to hydrogen bonding caused by silanol groups is reduced), and as a result, it is presumed that the dispersibility of the inorganic filler in the release layer 1 is improved. This increases the interface between the inorganic filler and the rubber matrix, and enhances the reinforcing effect of the inorganic filler. Furthermore, it is presumed that the slipperiness of the inorganic filler in the matrix is ​​improved during deformation of the rubber matrix. And, due to the improvement in the dispersibility and slipperiness of the inorganic filler, the mechanical strength (for example, mold followability, dimensional stability, etc.) of the release layer 1 due to the inorganic filler is improved.

[0105] Furthermore, the silane coupling agent may contain a silane coupling agent having a vinyl group. This introduces a vinyl group to the surface of the inorganic filler. Therefore, when the release layer 1 is cured, that is, when the vinyl group of the vinyl group-containing organopolysiloxane (A) and the hydride group of the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction to form a network (crosslinked structure) by these, the vinyl group of the inorganic filler (in the case of silica particles) also participates in the hydrosilylation reaction with the hydride group of the organohydrogenpolysiloxane (B), so that the inorganic filler is also incorporated into the network. This allows the release layer 1 to be formed with low hardness and high modulus.

[0106] As the silane coupling agent, a silane coupling agent having a hydrophobic group and a silane coupling agent having a vinyl group can be used in combination.

[0107] An example of the silane coupling agent is one represented by the following formula (4).

[0108] Y n -Si-(X) 4-n (4) In the above formula (4), n represents an integer of 1 to 3. Y represents any functional group having a hydrophobic group, a hydrophilic group, or a vinyl group, and when n is 1, it is a hydrophobic group, and when n is 2 or 3, at least one of them is a hydrophobic group. X represents a hydrolyzable group.

[0109] The hydrophobic group is an alkyl group having 1 to 6 carbon atoms, an aryl group, or a hydrocarbon group formed by combining these groups. Examples of the hydrophobic group include a methyl group, an ethyl group, a propyl group, and a phenyl group, and among these, a methyl group is preferable.

[0110] Examples of the hydrophilic group include a hydroxyl group, a sulfonic acid group, a carboxyl group, and a carbonyl group, and among these, a hydroxyl group is preferred. The hydrophilic group may be included as a functional group, but it is preferred that the hydrophilic group is not included from the viewpoint of imparting hydrophobicity to the silane coupling agent.

[0111] Further, examples of the hydrolyzable group include alkoxy groups such as methoxy and ethoxy groups, chloro groups, and silazane groups. Among these, silazane groups are preferred because of their high reactivity with inorganic fillers (in the case of silica particles). In addition, those having a silazane group as a hydrolyzable group can be easily obtained by adding (Y n -Si-) structures.

[0112] Specific examples of the silane coupling agent represented by the above formula (4) include, for example, those having a hydrophobic group as a functional group, such as alkoxysilanes, such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane; chlorosilanes, such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, and phenyltrichlorosilane; and hexamethyldisilazane. Examples of the silane having a vinyl group include alkoxysilanes such as methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane and vinylmethyldichlorosilane; and divinyltetramethyldisilazane. Among these, taking into consideration the above description, it is particularly preferable that the silane having a hydrophobic group is hexamethyldisilazane, and the silane having a vinyl group is divinyltetramethyldisilazane.

[0113] (catalyst) When the release layer 1 is formed by a curing reaction, the first resin composition may contain a catalyst. Examples of the catalyst include platinum or a platinum compound. As the platinum or platinum compound, a known one can be used, and examples thereof include platinum black, platinum supported on silica or carbon black, chloroplatinic acid or an alcohol solution of chloroplatinic acid, a complex salt of chloroplatinic acid and an olefin, and a complex salt of chloroplatinic acid and a vinyl siloxane. Platinum or a platinum compound may be used alone or in combination of two or more kinds.

[0114] In this embodiment, the content ratio of each component of the first resin composition is not particularly limited, but is set, for example, as follows.

[0115] In this embodiment, the upper limit of the content of the inorganic filler may be, for example, 60 parts by weight or less, preferably 50 parts by weight or less, and more preferably 40 parts by weight or less, relative to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A). This improves the mechanical strength, such as the hardness and tear strength, of the release film 11, and improves the balance of the releasability, mold followability, and dimensional stability. The lower limit of the content of the inorganic filler is not particularly limited, relative to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), but may be, for example, 10 parts by weight or more.

[0116] The silane coupling agent is preferably contained in an amount of 5 parts by weight or more and 100 parts by weight or less, more preferably 5 parts by weight or more and 40 parts by weight or less, relative to 100 parts by weight of the vinyl group-containing organopolysiloxane (A). This can reliably improve the dispersibility of the inorganic filler in the release layer 1.

[0117] The content of organohydrogenpolysiloxane (B) is preferably 0.5 parts by weight or more and 20 parts by weight or less, and more preferably 0.8 parts by weight or more and 15 parts by weight or less, per 100 parts by weight of the total amount of vinyl group-containing organopolysiloxane (A), inorganic filler, and silane coupling agent. By keeping the content of (B) within the above range, a more effective curing reaction may be achieved.

[0118] [Method of manufacturing the release layer] Next, a method for producing the release layer 1 of this embodiment will be described. As a method for producing the release layer 1 of this embodiment, the release layer 1 can be obtained by preparing the above-mentioned first resin composition, forming the first resin composition into a film, and curing the film. Details are provided below.

[0119] First, the components of the first resin composition are mixed uniformly using any kneading device to prepare the first resin composition. Hereinafter, details will be described using an example in which a silicone resin is used as the resin.

[0120] [1] For example, the vinyl group-containing organopolysiloxane (A), the inorganic filler, and the silane coupling agent are weighed out in predetermined amounts, and then kneaded in an arbitrary kneading device to obtain a kneaded mixture.

[0121] When obtaining this kneaded product, water may be added as necessary, which can ensure that the reaction between the silane coupling agent and the inorganic filler proceeds more reliably.

[0122] Furthermore, the above kneading is preferably carried out through a first step of heating at a first temperature and a second step of heating at a second temperature. This allows the surface of the inorganic filler to be surface-treated with a coupling agent in the first step, and allows by-products generated by the reaction between the inorganic filler and the coupling agent to be reliably removed from the kneaded product in the second step. Thereafter, component (A) may be added to the kneaded product obtained as necessary, and further kneaded. This allows the compatibility of the components in the kneaded product to be improved.

[0123] The first temperature is preferably, for example, about 40 to 120° C., and more preferably, for example, about 60 to 90° C. The second temperature is preferably, for example, about 130 to 210° C., and more preferably, for example, about 160 to 180° C.

[0124] Moreover, the atmosphere in the first step is preferably an inert atmosphere such as a nitrogen atmosphere, and the atmosphere in the second step is preferably a reduced pressure atmosphere.

[0125] Furthermore, the time for the first step is, for example, preferably about 0.3 to 1.5 hours, and more preferably about 0.5 to 1.2 hours, and the time for the second step is, for example, preferably about 0.7 to 3.0 hours, and more preferably about 1.0 to 2.0 hours.

[0126] By setting the above conditions for the first and second steps, the above effects can be obtained more significantly.

[0127] [2] Next, the organohydrogenpolysiloxane (B) and the catalyst are weighed out in predetermined amounts, and then, using any kneading device, the components are kneaded with the mixture prepared in the above step [1] to obtain a first resin composition. The obtained first resin composition may be a paste containing a solvent.

[0128] In addition, when mixing the components (B) and the catalyst, it is preferable to mix the mixture prepared in the above step [1] with the organohydrogenpolysiloxane (B) and the mixture prepared in the above step [1] with the catalyst, and then mix the mixtures together. This makes it possible to reliably disperse each component in the first resin composition without allowing the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) to proceed.

[0129] The temperature at which the components (B) and the catalyst are kneaded is, for example, preferably about 10 to 70°C, and more preferably about 25 to 30°C, as roll setting temperature.

[0130] Furthermore, the kneading time is, for example, preferably about 5 minutes to 1 hour, and more preferably about 10 to 40 minutes.

[0131] In the above steps [1] and [2], by setting the temperature within the above range, the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) can be more appropriately prevented or suppressed. In addition, in the above steps [1] and [2], by setting the kneading time within the above range, each component can be more reliably dispersed in the first resin composition.

[0132] The kneading device used in each of steps [1] and [2] is not particularly limited, but for example, a kneader, a two-roll mill, a Banbury mixer (continuous kneader), a pressure kneader, etc. can be used.

[0133] In addition, a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded mixture in step [2], which makes it possible to more effectively prevent or inhibit the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) even if the temperature of the kneaded mixture is set to a relatively high temperature.

[0134] [3] Next, the first resin composition obtained in the step [2] may be dissolved in a solvent to form a paste.

[0135] [4] Next, the first resin composition is processed into a film and cured to form the release layer 1. Specifically, the first resin composition is formed into a film by extrusion molding, calendar molding, press molding, coating, etc. During film formation, the surface shape of a roll or the like may be transferred or embossed.

[0136] In this embodiment, the curing step of the first resin composition is carried out, for example, by heating at 100 to 250° C. for 1 to 30 minutes (first curing) and then post-baking at 100 to 250° C. for 1 to 4 hours (second curing).

[0137] Through the steps as described above, the release layer 1 using the first resin composition of the present embodiment, that is, the release film 11, is obtained.

[0138] [Base material layer 2] In the release film 11 of the present embodiment, the base layer 2 is used from the viewpoint of imparting appropriate rigidity in order to ensure shape stability and production stability of the release film 11 and to ensure the release function of the release layer.

[0139] The thickness of the base layer 2 is preferably 5 μm or more and 50 μm or less, more preferably 9 μm or more and 35 μm or less, and even more preferably 12 μm or more and 25 μm or less. By setting the thickness of the base layer 2 to the above-mentioned lower limit or more, the rigidity of the release film 11 is increased, and it becomes easier to suppress excessive deformation and wrinkles. As a result, mold followability and dimensional stability are obtained. On the other hand, by setting the thickness of the base layer 2 to the above-mentioned upper limit or less, the rigidity of the release film 11 can be controlled, and a good balance between mold followability and releasability can be achieved.

[0140] The material of the base layer 2 may be one or more selected from the group consisting of poly-4-methyl-1-pentene resin, polyester resin, polyamide resin, and polyolefin resin. The polyester resin, polyamide resin, and polyolefin resin include those similar to those described above for the release layer 1. A suitable example of the polyolefin resin is a polypropylene resin.

[0141] Alternatively, a stretched film may be used as the base layer 2, and the stretching may be carried out by using a known method such as sequential biaxial stretching, simultaneous biaxial stretching, or tubular stretching.

[0142] [Release film manufacturing method] The release film 11 can be produced by a known method such as co-extrusion, extrusion lamination, dry lamination, inflation, etc. The release layer 1 may be formed on the base layer 2 by applying a first resin composition prepared in a paste form to the surface of the base layer 2. In the release film 11, for example, the release layer 1 and the base layer 2 may be produced separately and then bonded together using a laminator or the like. In addition, the release layer 1 and the base layer 2 may be bonded together directly or via an adhesive layer. The method for producing the base layer 2 is not limited, and specific examples include an inflation extrusion method and a T-die extrusion method.

[0143] [Uses and methods of use of release film] The release film 11 of the present embodiment is used for a purpose of being disposed between a mold to which a sealing resin is supplied and a semiconductor device to be resin-sealed in a resin-sealing process of a semiconductor device. That is, it may be a so-called mold-forming release film, or may be used for other purposes. As another use, for example, when a coverlay film (hereinafter also referred to as a "CL film") is bonded to a flexible film with an exposed circuit (hereinafter also referred to as a "circuit-exposed film") via an adhesive by hot pressing to produce a flexible printed circuit board (hereinafter also referred to as an "FPC"), it may be disposed between the cover film and a mold. In addition, it may be used as a release film when hardening a prepreg of a thermosetting resin such as CFRP, a release film for molding a thermosetting resin, a transfer release film for decoration to perform printing or the like on a product having a three-dimensional shape, and the like.

[0144] An example of a method for manufacturing a resin-encapsulated semiconductor device using the release film 11 will now be described.

[0145] The method for manufacturing a resin-encapsulated semiconductor device includes the following steps. (Step 1) Preparation of semiconductor device (Step 2) Release film installation process (Step 3) Sealing resin supply process (Step 4) Curing step (Step 5) Demolding of the molded body Each step will be described in detail below.

[0146] (Step 1) Preparation of semiconductor device The semiconductor device is formed by electrically connecting electrode pads on circuit wiring provided on a support and electrodes provided on a semiconductor element. Examples of the semiconductor element include optical elements such as a light emitting element and a light receiving element. An example of the light emitting element is an LED chip (light emitting diode), and an example of the light receiving element is an image sensor. The support is a substrate formed in any shape such as a circle or a polygon, etc. Examples of the support include a ceramic substrate, a silicone substrate, a metal substrate, a rigid substrate such as an epoxy resin or a BT resin, or a flexible substrate such as a polyimide resin or a polyethylene substrate.

[0147] (Step 2) Release film installation process The release film 11 is placed on a lower mold having a cavity recess for supplying the sealing resin. At this time, the release surface 3 of the release film 11 is placed on the front side, that is, so as to contact the sealing resin to be supplied later. The release film 11 is disposed in the cavity recess of the lower mold and along the surface of the flat portion surrounding the cavity recess. At this time, a suction port is provided on the flat portion surrounding the cavity recess to allow the release film 11 to conform to the shape of the cavity recess of the lower mold. Air, moisture, gas, etc. in the space between the release film 11 and the mold are sucked and discharged from the suction port using a suction device or the like, and vacuum adsorption is performed. Furthermore, in order to firmly fix the release film 11 to the mold, the release film 11 may be clamped by a chuck mechanism arranged at a position corresponding to the outer periphery of the sealing resin injection area, the outer periphery of the entire release film 11, or the outer periphery of the entire mold. Examples of the mold include a known metal mold and a resin mold.

[0148] (Step 3) Sealing resin supply process Next, a sealing resin is supplied to the recess of the mold in the region where the release film 11 is disposed. A known method can be used as the supplying method. In addition, the sealing resin can be a known resin, for example, silicone resin, epoxy resin, acrylic resin, fluorine resin, polyimide resin, silicone modified epoxy resin, etc., or a mixture of these, and precursors thereof. In this embodiment, when the release film 11 is applied to a compression molding method, the sealing resin is preferably processed into a tablet, granule, sealed particle, or sheet shape. In the mold, the sealing resin is heated to a predetermined temperature and is in a fluid state.

[0149] (Step 4) Curing step Next, the semiconductor device to be molded is attached to an upper mold provided with a protruding fixture for holding the outer edge of the molding object so that the molding object does not fall, and the surface of the semiconductor device on which the semiconductor element is provided is placed opposite the lower mold, and the mold is pressed against the mold in which the sealing resin has been supplied into the recess. At this time, the fixture of the upper mold fits into the groove of the lower mold, and the semiconductor element is covered with the sealing resin. The sealing resin is then heated and pressurized to harden it, and a molded body is obtained. When the sealing resin is a precursor of a curable resin, it may be cured by heating and irradiation with active energy rays, examples of which include radiation, ultraviolet rays, visible light, and electron beams.

[0150] (Step 5) Demolding of the molded body The molded body is then removed from the mold. In the mold-removing process, air, moisture, gas, etc. are supplied between the release film 11 and the mold, so that the release film 11 is peeled off from the mold and the molded body is removed. At the same time or after this, the release film 11 is released from the molded body. When there is one semiconductor element provided on the support, this molded body becomes a resin-sealed semiconductor device. This makes it possible to obtain a semiconductor device with a good appearance.

[0151] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of the present invention are included in the present invention. Below, examples of reference forms are given. 1. A release film whose viscoelasticity spectrum measured in dynamic viscoelasticity (DMA) measurements at a heating rate of 5°C / min and a frequency of 1 Hz satisfies the following (a) and (b). (a) the storage modulus at 150°C is 50 MPa or more; (b) When the storage modulus at 25°C is E'1 [MPa] and the storage modulus at 100°C is E'2 [MPa], (E'1-E'2) [MPa] / (100-25) [°C] is 5 to 60. 2. A release film, the viscoelasticity spectrum of which is measured in a dynamic viscoelasticity (DMA) measurement at a heating rate of 5°C / min and a frequency of 1 Hz, satisfies the following (c). (c) It has an equilibrium elastic modulus at least in the range of 200° C. or more and 250° C. or less, and the equilibrium elastic modulus is 1 MPa or more. 3. A release film according to 1. or 2., in which the viscoelasticity spectrum measured in dynamic viscoelasticity (DMA) measurement at a heating rate of 5°C / min and a frequency of 1 Hz satisfies the following condition (d): (d) At 180°C, the loss modulus / storage modulus (loss tangent) in the MD direction is 0.05 or more and 0.2 or less. 4. A release film according to any one of 1. to 3., which satisfies the following condition (e): (e) The release film has a 5% tensile strength (5% modulus) at 180°C of 1 MPa or more and 5 MPa or less. 5. A release film described in any one of 1. to 4., wherein the release film has a multilayer structure including a release layer that forms at least one surface of the release film and a base layer made of a material different from that of the release layer. 6. A release film according to any one of 1 to 5, which is intended to be disposed between a mold and a semiconductor device in a resin-sealing semiconductor device molding process in which the semiconductor device is resin-sealed. EXAMPLES

[0152] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0153] (1) Raw materials The raw material components used in the examples and comparative examples shown in Table 1 are shown below. (Vinyl-containing organopolysiloxane (A)) Low vinyl group-containing linear organopolysiloxane (A1-1): Vinyl group-containing dimethylpolysiloxane (structure represented by formula (1-1) and R 1 (Structure in which only the terminal is vinyl) High vinyl group-containing linear organopolysiloxane (A1-2): Vinyl group-containing dimethylpolysiloxane (structure represented by formula (1-1) and R 1 and R 2 is a vinyl group)

[0154] (Organohydrogenpolysiloxane (B)) Momentive: "TC-25D"

[0155] (Inorganic filler) Inorganic filler (C): Silica fine particles (particle size 7 nm, specific surface area 300 m 2 / g), manufactured by Nippon Aerosil Co., Ltd., "AEROSIL300"

[0156] (Silane coupling agent) Silane coupling agent (D-1): Hexamethyldisilazane (HMDZ), manufactured by Gelest, "HEXAMETHYLDISILAZANE (SIH6110.1)" Silane coupling agent (D-2): Divinyltetramethyldisilazane, manufactured by Gelest, "1,3-DIVINYLTETRAMETHYLDISILAZANE (SID4612.0)"

[0157] (Platinum or platinum compounds (E)) Momentive: "TC-25A"

[0158] (Synthesis of vinyl group-containing organopolysiloxane (A)) [Synthesis Scheme 1: Synthesis of low vinyl group-containing linear organopolysiloxane (A1-1)] A low-vinyl-group-containing linear organopolysiloxane (A1-1) was synthesized according to the following formula (5). That is, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane and 0.1 g of potassium siliconate were placed in a 300 mL separable flask equipped with a cooling tube and stirring blade and replaced with Ar gas, and the temperature was raised and the mixture was stirred at 120° C. for 30 minutes. At this time, an increase in viscosity was confirmed. The mixture was then heated to 155° C. and stirred for 3 hours, after which 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added and the mixture was stirred at 155° C. for an additional 4 hours. After four hours, the mixture was diluted with 250 mL of toluene and then washed three times with water. The washed organic layer was washed several times with 1.5 L of methanol for reprecipitation purification, and the oligomer and polymer were separated. The resulting polymer was dried overnight at 60°C under reduced pressure to obtain a low-vinyl-group-containing linear organopolysiloxane (A1-1) (Mn = 2.2 × 10 5 , Mw=4.8×10 5 The vinyl group content calculated from H-NMR spectrum measurement was 0.04 mol %.

[0159] [ka]

[0160] [Synthesis Scheme 2: Synthesis of high vinyl group-containing linear organopolysiloxane (A1-2)] A highly vinyl-containing linear organopolysiloxane (A1-2) was synthesized as shown in formula (6) below by the same synthesis process as for (A1-1), except that 0.86 g (2.5 mmol) of 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane was used in addition to 74.7 g (252 mmol) of octamethylcyclotetrasiloxane in the synthesis process for (A1-1) above. (Mn=2.3×10 5 , Mw=5.0×10 5 The vinyl group content calculated from H-NMR spectrum measurement was 0.93 mol %. [ka]

[0161] (2) Preparation of first resin composition (preparation of release layer) Each of the first resin compositions was prepared as follows. First, a mixture of 90% vinyl group-containing organopolysiloxane (A), a silane coupling agent, and water (F) was pre-kneaded in the proportions shown in Table 1 below, and then an inorganic filler was added to the mixture and further kneaded to obtain a kneaded product (silicone rubber compound). Here, the kneading after the addition of the inorganic filler was carried out through a first step of kneading for 1 hour under conditions of 60 to 90°C in a nitrogen atmosphere for the coupling reaction, and a second step of kneading for 2 hours under conditions of 160 to 180°C in a reduced pressure atmosphere for the removal of the by-product (ammonia). Thereafter, the mixture was cooled, and the remaining 10% of the vinyl group-containing organopolysiloxane (A) was added in two portions and kneaded for 20 minutes. Next, organohydrogenpolysiloxane (B) (TC-25D) and platinum or platinum compound (E) (TC-25A) were added to 100 parts by weight of the obtained kneaded product (silicone rubber compound) in the proportions shown in Table 1 below, and the mixture was kneaded with a roll to obtain each first resin composition.

[0162] [Table 1]

[0163] (3) Preparation of a release film with a base layer <Example 1> As shown in Table 2, biaxially oriented polybutylene terephthalate (OPBT1: Toyobo Co., Ltd., Toyobo Ester (registered trademark) film, DE048) 15 μm thick was used as the base layer, and the paste (solid content 25 mass%, decane solvent) made of the first resin composition prepared in (2) above was applied onto the base layer using a bar coater and cured at 180° C. for 120 minutes to obtain a release film having a release layer on the base layer. The thickness of the release layer of the obtained release film was 35 μm, and the surface roughness Rz of the release surface of the release layer was 0.1 μm.

[0164] <Example 2> As shown in Table 2, a release film was produced in the same manner as in Example 1, except that a matte film was sandwiched during the film-forming process using a paste made of the first resin composition to create an uneven surface on the release layer.

[0165] <Example 3> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the thickness of the release layer was changed to 10 μm.

[0166] <Example 4> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the thickness of the release layer was changed to 70 μm.

[0167] <Example 5> As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the first resin composition used in forming the release layer was changed to the composition shown in Table 2.

[0168] <Example 6> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the base layer was changed to biaxially oriented polybutylene terephthalate (OPET2: manufactured by Kohjin Film & Chemicals, Boblet ST20) with a thickness of 20 μm and the thickness of the release layer was changed to 30 μm.

[0169] <Example 7> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the base layer was changed to biaxially oriented polyethylene terephthalate (OPET1: Toyobo Co., Ltd., Toyobo Ester (registered trademark) film) with a thickness of 9 μm and the release layer was changed to a thickness of 41 μm.

[0170] <Example 8> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the base layer was changed to biaxially oriented polyethylene terephthalate (Toyobo Co., Ltd., Toyobo Ester (registered trademark) film,) having a thickness of 12 μm and the release layer was changed to a thickness of 38 μm.

[0171] <Example 9> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the base layer was changed to biaxially oriented polyethylene terephthalate (OPET2: Toyobo Film Solutions Co., Ltd., Teflex (registered trademark) film FW2) with a thickness of 13 μm and the thickness of the release layer was changed to 37 μm.

[0172] <Comparative Example 1> As shown in Table 2, a release film was produced in the same manner as in Example 1, except that the first resin composition used in forming the release layer was changed to the composition shown in Table 2.

[0173] <Comparative Example 2> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the base layer was changed to biaxially oriented polyethylene terephthalate (OPET1: Toyobo Co., Ltd., Toyobo Ester (registered trademark) film) with a thickness of 19 μm and the release layer was changed to a thickness of 31 μm.

[0174] <Comparative Example 3> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the substrate layer was changed to a film (35 μm thick) made from poly 4-methyl 1-pentene resin (TPX RT31, manufactured by Mitsui Chemicals, Inc.).

[0175] <Comparative Example 4> As shown in Table 2, a release film was prepared in the same manner as in Example 1, except that the base layer was changed to a film (25 μm thick) made from polybutylene terephthalate elastomer resin (Hytrel 6347, manufactured by Toray DuPont) and the thickness of the release layer was changed to 25 μm.

[0176] (4) Measurement and evaluation The following measurements and evaluations were carried out using the obtained release film. The results are shown in Table 2.

[0177] (a)-(d): Dynamic viscoelasticity (DMA) was measured using a DMA7100 (Hitachi High-Tech Science Corporation) at a heating rate of 5°C / min and a frequency of 1Hz. From the viscoelasticity spectrum, the storage modulus at 150°C, the storage modulus at 25°C E'1 [MPa], the storage modulus at 100°C E'2 [MPa], and the equilibrium modulus were calculated. The obtained E'1 and E'2 were applied to the following equation. (E'1-E'2)[MPa] / (100-25)[℃] Furthermore, the loss modulus / storage modulus (loss tangent) in the MD direction at 180° C. of the release film was determined. Dynamic viscoelasticity (DMA) measurements were performed using a dynamic viscoelasticity measuring device ("DMA7100" manufactured by Hitachi High-Tech Science Corporation) under the following measurement conditions. (Measurement conditions) Frequency: 1Hz Temperature range: 20~250℃ Heating rate: 5℃ / min Test piece: 4mm wide x 20mm Test mode: Tensile

[0178] (e) The 180°C, 5% tensile strength (5% modulus) of the release film was calculated from the SS curve obtained by measurement in accordance with the tensile test JIS-K7127.

[0179] (i) Measurement of the surface roughness Rz of the release surface of the release film Measurements were performed in accordance with JIS B0601:2013.

[0180] (ii) Evaluation of the appearance of the molded product First, the following granular thermosetting resin composition was prepared as a sealing resin. (raw materials) Epoxy resin 1: Biphenyl aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC-3000) Epoxy resin 2: Biphenyl type epoxy resin (Mitsubishi Chemical, YL6677) Hardener 1: Phenol aralkyl resin containing biphenylene skeleton (manufactured by Nippon Kayaku Co., Ltd., GPH-65) Hardener 2: Triphenylmethane type phenolic resin modified with formaldehyde (Air Water Corporation, HE910-20) Curing accelerator: Triphenylphosphine (Hokko Chemical Industry Co., Ltd., TPP) Inorganic filler: Fused spherical silica (Denki Kagaku Kogyosha, FB-950FC) Colorant: Carbon black (Mitsubishi Chemical, MA-600) Coupling agent: N-phenyl-γ-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., KBM-573) Release agent: Carnauba wax (Nikko Fine Co., Ltd., Nikko Carnauba) (procedure) The above-mentioned epoxy resin 1 was prepared in an amount of 4.5 parts by mass, epoxy resin 2 in an amount of 4.5 parts by mass, curing agent 1 in an amount of 2.8 parts by mass, curing agent 2 in an amount of 2.8 parts by mass, curing accelerator in an amount of 0.4 parts by mass, inorganic filler in an amount of 84.2 parts by mass, colorant in an amount of 0.2 parts by mass, coupling agent in an amount of 0.4 parts by mass, and release agent in an amount of 0.2 parts by mass. Next, the raw material components were mixed at room temperature using a mixer, and then roll-kneaded while being heated with two rolls at 45°C and 90°C to obtain a kneaded product. Next, the kneaded product was cooled and then pulverized to obtain a granular thermosetting resin composition.

[0181] Next, using each release film, the thermosetting resin composition was cured (resin sealing) according to the following procedure. First, five semiconductor elements each having a thickness of 0.3 mm and a square of 7.5 mm were bonded with silver paste onto an organic substrate having a thickness of 0.4 mm, a width of 65 mm, and a length of 190 mm, and gold wires having a diameter of 18 μm and a length of 7 mm were bonded at a pitch interval of 60 μm. Next, the mold temperature of a compression molding machine (TOWA Corporation, PMC1040) was set to 175° C. in advance. Next, the organic substrate was fixed to the upper mold so that the surface on which the semiconductor elements were mounted faced the lower mold. Next, the release film prepared in each of the Examples and Comparative Examples was placed on the lower mold, and the mold inner space was evacuated to allow the release film to follow the mold. Then, the granular thermosetting resin composition (encapsulating resin composition) prepared was uniformly supplied onto the release film. Next, immediately after supplying the encapsulating resin composition, the mold was clamped until the gap between the organic substrate and the release film was 4 mm, and at the same time, the inside of the cavity formed by the lower mold and the upper mold was depressurized to a vacuum degree of 0.8 Torr in 4 seconds. Then, while continuing the depressurization, the mold was completely clamped in 12 seconds, and encapsulating molding was performed under conditions of a molding pressure of 3.9 MPa and a curing time of 90 seconds.

[0182] (iii) Evaluation of release films [Mold followability] In the above procedure, the degree of air entrapment between the mold and the release film when the release film was made to follow the mold by vacuum drawing was evaluated according to the following criteria. ◎: No air pockets ○: There are small air pockets, but no practical problems △: There was a small air pocket, which reduced the degree of vacuum for film adsorption. ×: Large air pockets cause poor tracking (or evaluation is impossible)

[0183] [Dimensional stability] In the above procedure, the appearance (wrinkles, etc.) of the cured product after it was released from the release film after molding was evaluated according to the following criteria. 〇: No wrinkles or deformations, no problems △: There are some wrinkles, but no problem in use ×: Large wrinkles and molding defects occurred

[0184] [Mold releasability] In the above procedure, the release behavior when the cured product was released from the release film after molding and the state of the cured product (displacement, bending, etc.) were evaluated according to the following criteria. 〇: No problems with demolding or molded products △: The molded product shifts or bends when released from the mold, but this does not pose a problem in practical use. ×: Unable to release from the mold, or molded product had significant misalignment or deflection

[0185] [Interlaminar strength] In the above procedure, the state of the release layer when the cured product was released from the release film after molding was evaluated according to the following criteria. ○: No peeling of the release layer, no problem △: Some of the release layer is lifted off the base layer, but this does not pose a problem in practical use. ×: The release layer was largely peeled off from the base layer.

[0186] [Table 2] [Explanation of symbols]

[0187] 1 Release layer 2 Base material layer 3 Release surface 11 Release film

Claims

1. A release film, the viscoelasticity spectrum of which, in a dynamic viscoelasticity (DMA) measurement, is measured at a temperature rise rate of 5° C. / min and a frequency of 1 Hz, satisfies the following (c): (c) It has an equilibrium elastic modulus at least in the range of 200° C. or more and 250° C. or less, and the equilibrium elastic modulus is 1 MPa or more.

2. A release film, the viscoelasticity spectrum of which, as measured in a dynamic viscoelasticity (DMA) measurement at a temperature rise rate of 5° C. / min and a frequency of 1 Hz, satisfies the following (a), (b), and (d): (a) the storage modulus at 150° C. is 50 MPa or more; (b) when the storage modulus at 25°C is E'1 [MPa] and the storage modulus at 100°C is E'2 [MPa], (E'1-E'2) [MPa] / (100-25) [°C] is 5 to 60; (d) The loss modulus / storage modulus (loss tangent) in the MD direction at 180° C. is 0.05 or more and 0.2 or less.

3. A release film, the viscoelasticity spectrum measured in dynamic viscoelasticity (DMA) measurement at a heating rate of 5°C / min and a frequency of 1 Hz satisfies the following (a), (b), and (e). (a) the storage modulus at 150° C. is 50 MPa or more; (b) when the storage modulus at 25°C is E'1 [MPa] and the storage modulus at 100°C is E'2 [MPa], (E'1-E'2) [MPa] / (100-25) [°C] is 5 to 60; (e) The release film has a 5% tensile strength (5% modulus) at 180° C. of 1 MPa or more and 5 MPa or less.

4. A release film as described in claim 1 or 3, wherein the viscoelasticity spectrum measured in dynamic viscoelasticity (DMA) measurement at a heating rate of 5°C / min and a frequency of 1 Hz satisfies the following (d). (d) The loss modulus / storage modulus (loss tangent) in the MD direction at 180° C. is 0.05 or more and 0.2 or less.

5. A release film described in claim 1 or 2, which satisfies the following (e). (e) The release film has a 5% tensile strength (5% modulus) at 180° C. of 1 MPa or more and 5 MPa or less.

6. The release film according to claim 1 , wherein the release film has a multilayer structure including a release layer that is on at least one side of the release film, and a base layer made of a material different from that of the release layer.

7. The release film according to claim 1 , which is used for being disposed between a mold and a semiconductor device in a resin-sealing semiconductor device molding process for resin-sealing the semiconductor device.

Images