Resin sheet manufacturing method and resin sheet

Abstract

The present invention provides a method for manufacturing a resin sheet that does not form abrasion marks on the sheet surface, that is, it is possible to suppress the occurrence of scratches. [Solution] In a manufacturing method for obtaining a resin sheet by slicing a resin molded body, in which surfaces X and Y are arranged at a distance equal to the height between them, with a slicing blade, the lower surface of the resin molded body is kept in a non-contact state when moving the resin molded body toward the slicing blade.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing resin sheets and to resin sheets. [Background technology]

[0002] In recent years, electronic components such as plasma display panels (PDPs) and integrated circuit (IC) chips have been generating increasing amounts of heat as their performance has improved. As a result, electronic devices using these components require measures to prevent functional failures caused by temperature increases in the electronic components.

[0003] To prevent malfunctions caused by temperature increases in electronic components, a common method is to promote heat dissipation by attaching heat sinks, heat dissipation plates, or heat fins made of metal to the heat-generating elements of electronic components. When using heat sinks, a resin sheet with high thermal conductivity is often used as an intermediary to ensure efficient heat transfer between the heat-generating element and the heat sink.

[0004] Conventionally, a manufacturing method has been proposed for producing resin sheets with excellent thermal conductivity, which involves supporting a resin molded body so that it can slide on a sliding surface, and supporting a single blade, whose tip protrudes from the sliding surface, from the opposite side of the resin molded body from the sliding surface, while pressing the resin molded body against the sliding surface and sliding it to slice the resin molded body (see, for example, Patent Document 1). Furthermore, Patent Document 2 discloses a technique for obtaining a resin sheet in which the adhesive strength of the first surface and the second surface differs by slicing a molded body containing an inorganic material and an organic polymer compound using a knife with an asymmetrical blade cross-sectional shape. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-218504 [Patent Document 2] Japanese Patent Publication No. 2011-074303 [Overview of the project] [Problems that the invention aims to solve]

[0006] Here, resin sheets are required to have as few scratches as possible from the perspective of improving quality. However, in the conventional manufacturing technology described above, sheets were produced by slicing a molded body by sliding it against a sliding surface with a small protruding blade, similar to a plane. In this manufacturing method, when the molded body slides on the sliding surface, drag marks can occur on the surface of the resulting sheet due to friction between the sliding surface and the surface of the molded body. Such marks that can be formed on the sheet surface, i.e., scratches on the sheet surface, can lead to a decrease in sheet manufacturing yield and a decline in sheet quality.

[0007] Therefore, the present invention aims to provide a method for manufacturing a resin sheet that can suppress the occurrence of scratches. [Means for solving the problem]

[0008] The inventors have conducted diligent studies to achieve the above objectives. The inventors have developed a resin sheet manufacturing method that includes slicing the surface X side of a resin molded body, in which surfaces X and Y are arranged at a distance of height apart, by moving the body toward a slicing blade, wherein the manufacturing method includes a starting step of holding the resin molded body with a movable holding device and placing it at the slicing start position so that surface X is in a non-contact state, a moving step of moving the resin molded body toward a slicing blade after the starting step, and a slicing step of slicing the resin molded body into a sheet, and the manufacturing method includes maintaining the non-contact state of surface X during the moving step, thereby suppressing the occurrence of scratches on the resulting resin sheet.

[0009] In other words, the present invention aims to advantageously solve the above problems, and [1] the resin sheet manufacturing method of the present invention is a resin sheet manufacturing method that includes slicing a resin molded body having a shape in which surfaces X and Y are arranged at a distance equal to the height of the resin molded body by moving it in a transverse direction with respect to the height direction of the resin molded body toward a slicing blade fixed to a blade fixing base, wherein the resin molded body is held by a movable holding device and placed at a slicing start position with the surface closer to the slicing blade as surface X of the two surfaces X and Y, and further, the surface X is in a non-contact state, and after the starting step, the moving step is to move the resin molded body toward the slicing blade, and the slicing step is to slice the resin molded body into a sheet, wherein the non-contact state of the surface X of the resin molded body is maintained during the moving step. According to this resin sheet manufacturing method, it is possible to manufacture a resin sheet without scratches, in particular traces made by dragging the surface (hereinafter sometimes referred to as "scratches" in this specification).

[0010] [2] In the resin sheet manufacturing method described in [1] above, the resin molded body preferably contains resin and oriented thermal conductive filler. Here, "oriented thermal conductive filler" refers to a thermal conductive filler whose orientation angle is 30° or more and 90° or less with respect to the main surface of the resin sheet. The orientation angle can be measured by the method described in the examples.

[0011] [3] In the resin sheet manufacturing method of [1] or [2] above, it is preferable that the storage modulus G' of the resin molded article at 40°C is 1,000 kPa or more and 12,000 kPa or less. The "storage modulus" can be determined using the method described in the examples.

[0012] [4] In any of the resin sheet manufacturing methods described in [1] to [3] above, it is preferable that the holding device holds at least a portion of all surfaces other than surface X and surface Y that constitute the resin molded body.

[0013] [5] In any of the resin sheet manufacturing methods described in [1] to [4] above, the resin molded body is a rectangular parallelepiped, the holding device comprises a plurality of support members that hold at least four faces of the resin molded body, and when the lower surface of the rectangular parallelepiped is referred to as surface X and the upper surface as surface Y, all faces other than surfaces X and Y that constitute the rectangular parallelepiped are, with respect to the sides perpendicular to the height direction of the resin molded body, respectively, preferably in the starting step, all faces other than surfaces X and Y are held by one of the plurality of support members having a length of 80% or more of the length of the horizontal side on each face.

[0014] [6] In any of the resin sheet manufacturing methods described in [1] to [5] above, it is preferable that the amount of protrusion of the surface X side of the resin molded body from the holding device is 8 mm or more and 50 mm or less.

[0015] [7] In any of the resin sheet manufacturing methods described in [1] to [6] above, it is preferable that the relief angle of the slicing blade is greater than 0° and 8° or less, and the rake angle of the slicing blade is 60° or more and 70° or less.

[0016] [8] The resin sheet of the present invention is characterized by being free from scratches with a depth of 3 μm or more, a width of 100 μm or more, and a length of 1000 μm or more. Such a resin sheet is of high quality. Damage to the sheet can be checked according to the methods described in the examples of this specification.

[0017] [9] The resin sheet in [8] above preferably contains resin and oriented thermal conductive filler.

[0018]

[10] The resin sheet described in [8] or [9] above has an absolute difference of tack force of 1.8 N / cm between the two main surfaces of the resin sheet. 2 It is preferable that the above conditions are met. The tack force can be measured according to the method described in the examples of this specification.

[0019]

[11] In the resin sheet according to any one of the above [8] to

[10] , of the two main surfaces of the resin sheet, the surface with both lower surface roughness Sa and Sz is defined as surface S1, and the other surface is defined as surface S2, and it is preferable that the tack force of the surface S1 is higher than the tack force of the surface S2. The surface roughness Sa and Sz can be measured according to the methods described in the Examples of the present specification. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a method for producing a resin sheet and the like that can suppress the occurrence of scratches. [Brief Description of the Drawings]

[0021] [Figure 1] It is a diagram for explaining a method for producing a resin sheet according to one example. [Figure 2A] It is a schematic diagram for explaining the relationship between a resin molded body according to one example and a resin sheet obtained by slicing. [Figure 2B] It is a partial cross-sectional view of a resin sheet according to one example. [Figure 3] It is a schematic diagram illustrating a state in which a resin molded body is held by a support member in one example. [Figure 4] It is a top view of FIG. 3. [Mode for Carrying Out the Invention]

[0022] Hereinafter, embodiments of the present invention will be described in detail. Each constituent element disclosed in the present embodiment, as well as the preferred aspects, numerical ranges, and each threshold value defining such numerical ranges indicated for each constituent element, can be independently combined with each other in all possible aspects.

[0023] Herein, the resin sheet manufacturing method of the present invention allows for the efficient production of resin sheets. Furthermore, the resin sheet of the present invention can be used as a resin sheet by sandwiching it between a heat-generating element such as an electronic component and a heat sink such as a metal heat sink, heat sink plate, or heat sink fin.

[0024] (Method for manufacturing resin sheets) The present invention relates to a resin sheet manufacturing method which involves slicing a resin molded body having a shape in which surfaces X and Y are arranged at a distance equal to the height of the resin molded body by moving it in a transverse direction relative to the height of the resin molded body toward a slicing blade fixed to a blade fixing base. Here, in this specification, of surfaces X and Y, the surface closer to the slicing blade is referred to as surface X. The manufacturing method of the present invention includes a starting step in which the resin molded body is first held by a movable holding device and placed at the slicing starting position, and further, a starting step in which the surface X is in a non-contact state, a moving step in which the resin molded body is moved toward the slicing blade after the starting step, and a slicing step in which the resin molded body is sliced ​​into a sheet. Here, in the moving step, it is necessary to maintain the non-contact state of surface X of the resin molded body. In this specification, "(surface X) non-contact state" means a state in which surface X does not come into contact with any object. For example, conventionally, when slicing a resin molded body, it was moved by sliding it on a support base that supported the resin molded body, and further, by pressing it as needed, to reach the position of the blade. Therefore, friction between the surface of the molded resin body and the support during movement sometimes caused scuff marks on the surface of the molded resin body. However, in the manufacturing method of the present invention, such a step is eliminated, and the surface X of the molded resin body (the part where friction with the support surface occurred in the conventional method) moves toward the blade while remaining in a non-contact state, thus suppressing the occurrence of scratches. By suppressing the occurrence of scratches on the resin sheet, the manufacturing yield can be improved, and the surface accuracy of the resulting resin sheet can be enhanced.

[0025] The resin sheet manufacturing method may include other processes besides those described above. Such processes include the manufacturing process for resin molded articles.

[0026] <Resin molded product> In a resin molded article, surfaces X and Y are arranged with a distance equal to the height between them. Here, the "height" of the resin molded article means the length of the axis that coincides with the shortest distance between two surfaces included in the resin molded article, among the axes that extend transversely to the direction of movement, i.e., the slicing direction, when the slicing device used in carrying out the manufacturing method of the present invention is a device in which the direction of movement of the resin molded article during slicing coincides with the slicing direction. For example, when the resin molded article is rectangular in shape and is thinly sliced ​​along the shape of the rectangular prism, i.e., along one surface of the rectangular prism, the height direction of the resin molded article is perpendicular to the slicing direction (i.e., intersects at 90°).

[0027] <Slicing device> A slicing apparatus capable of implementing the manufacturing method described in one example comprises a slicing blade fixed to a blade fixing base. Figure 1 shows a schematic configuration of a slicing apparatus 100 capable of implementing the manufacturing method described in one example. The slicing apparatus 100 may comprise a slicing blade 11 fixed to a blade fixing base 10, a support base 12, support members 21-23, and a holding member 31. Specifically, support members 21-23 are chuck members and together constitute a holding device 20. Of the support members 21-23, support members 21 and 22 are each positioned on one surface of the rectangular resin molded body 1 and are pressed in the direction of the center of gravity of the resin molded body 1 with a load W1. Support member 23, as also clearly shown in Figure 4 described later, is an L-shaped support member and cooperates with support members 21 and 22 to support the resin molded body 1. The holding device 20, composed of support members 21-23, is configured to be movable. The holding device 20 moves to move the resin molded body 1 relative to the slicing blade 11, thereby cutting out a resin sheet. At this time, by bringing the resin molded body 1 into contact with the slicing blade 11 at an appropriate angle and further moving it while maintaining a constant distance between the surface X and the cutting position by the slicing blade 11, a resin sheet with a uniform thickness, i.e., excellent thickness accuracy, can be obtained. As shown in Figure 1, the surface of the resin molded body 1 closer to the slicing blade is referred to as surface X, and the surface further away (i.e., the top surface in the illustrated configuration) is referred to as surface Y. Generally, the resin molded body 1 tends to "float" in the surface Y direction during cutting due to the influence of cutting resistance, but to prevent this, an appropriate load W2 can be applied to the resin molded body 1 by the restraining member 31.

[0028] As shown in Figure 1, the slicing blade 11 protrudes from the blade holder 10 by a height H1. The resin molded body 1 also protrudes from the holding device 20 by a protrusion amount L1. Furthermore, if the distance between the holding device 20 and the surface of the support base 12 is D1, then the relationship D1 > L1 holds, indicating that the surface X of the resin molded body 1 is in a non-contact state.

[0029] Furthermore, in Figure 1, the slicing blade 11 is shown as a double-edged blade as an example, but the slicing blade 11 is not limited to this and may be single-edged. When the slicing blade 11 is double-edged, it is preferable that the relief angle of the slicing blade is greater than 0° and 8° or less, and the rake angle of the slicing blade is 60° or more and 70° or less. In addition, it is preferable that the relief angle of the slicing blade is 3° or more, and the rake angle is 66° or less. If the rake angle and relief angle of the slicing blade are within the above range, in particular, if the rake angle is below the above upper limit, the difference in tack force between the front and back surfaces of the obtained sheet can be increased. The reason for this is not clear, but will be explained with reference to Figures 2A and 2B. Figure 2A schematically shows the relationship between the relief surface 11a and the rake surface 11b of the double-edged slicing blade 11, the resin molded body 1, and the resin sheet 2 obtained by slicing. When slicing the nth sheet, the surface S1 of the resin sheet rubs against the rake surface 11b of the slicing blade 11. When slicing the (n-1)th sheet, the surface S2 of the resin sheet rubs against the relief surface 11a of the slicing blade 11. The friction between the surface S2 of the resin sheet and the relief surface 11a of the slicing blade 11 is smaller than the friction between the surface S1 of the resin sheet and the scoop surface 11b of the slicing blade 11. Furthermore, as described above, in the manufacturing method of the present invention, it is preferable that the surface S2 of the resin sheet, which was the surface X of the resin molded body 1 before the start of the slicing process, is also cut while remaining in a non-contact state. This is because the occurrence of scratches can be suppressed even further. Here, if friction occurs on the surface of the resin molded body, it is thought that a coating layer 2a made of resin drawn out to the surface layer by friction can be formed on the surface of the resin sheet 2, as shown in the partial cross-sectional view of the resin sheet in Figure 2B. In the resin sheet, the thermal conductive filler F is oriented at an angle of approximately 90° to the main surface in the illustrated embodiment. The thickness of the coating layer, or whether the resin drawn out to the surface layer by friction can form a coating layer, is thought to depend on the strength of the friction. Specifically, it is thought that a thicker coating layer can be formed on a surface subjected to stronger frictional force. Conversely, if the friction generated is weak, the extraction of resin to the surface is suppressed, or even if it is extracted, it is only in a very small amount and does not lead to the formation of a coating layer.Furthermore, the resin coating layer 2a is considered to have a higher tack force than the surface S2 on which the coating layer is not formed. For the reasons described above, it is considered that the surface S2 of the resin sheet obtained according to the manufacturing method of the present invention tends to have a lower tack force than the surface S1.

[0030] <Resin molded product> The resin molded article comprises a resin and an oriented thermal conductive filler. The resin molded article may optionally contain other components. Furthermore, the storage modulus G' of the resin molded article at 40°C is preferably 1,000 kPa or more, more preferably 1,500 kPa or more, preferably 12,000 kPa or less, more preferably 10,000 kPa or less, even more preferably 8,000 kPa or less, and particularly preferably 5,500 kPa or less. If the storage modulus G' is within the above range, the thickness accuracy of the resulting resin sheet can be improved.

[0031] <<Resin>> The resin included in the resin sheet is not particularly limited, and any resin can be used. The resin can function as a binder that holds the thermal conductive filler within the sheet. For example, both liquid resins and solid resins can be used as the resin. One type of resin may be used alone, or two or more types may be used in combination. For example, the resin sheet may contain at least one of a liquid resin and a solid resin, but from the viewpoint of further reducing the thickness and thermal resistance of the resin sheet, it is preferable that the resin sheet contains both a liquid resin and a solid resin.

[0032] [Liquid resin] Furthermore, as for the liquid resin, there are no particular limitations as long as it is liquid at room temperature and atmospheric pressure; for example, a thermoplastic resin that is liquid at room temperature and atmospheric pressure can be used. In this invention, "room temperature" refers to 23°C, and "atmospheric pressure" refers to 1 atm (absolute pressure).

[0033] Examples of liquid resins include fluororesins, silicone resins, acrylic resins, and epoxy resins. These may be used individually or in combination of two or more. By using at least one of silicone resin and fluororesin as the liquid resin, the flame retardancy of the resin sheet can be improved. Furthermore, by using fluororesin as the liquid resin, the heat resistance, oil resistance, and chemical resistance of the resulting resin sheet can be improved. Moreover, by using acrylic resin as the liquid resin, the adhesion of the resin sheet to metal is enhanced, ensuring sufficient contact between the resin sheet and metal components such as heat sinks, even when electronic component packages or electronic devices are deformed.

[0034] [Solid resin] As for the solid resin, there are no particular limitations as long as it is not liquid at room temperature and atmospheric pressure. For example, thermoplastic resins that are solid at room temperature and atmospheric pressure, and thermosetting resins that are solid at room temperature and atmospheric pressure can be used.

[0035] {A thermoplastic resin that is solid at room temperature and atmospheric pressure} Examples of thermoplastic resins that are solid at room temperature and pressure include acrylic resins such as poly(2-ethylhexyl acrylate), copolymers of acrylic acid and 2-ethylhexyl acrylate, polymethacrylic acid or its esters, polyacrylic acid or its esters; silicone resins; fluororesins; polyethylene; polypropylene; ethylene-propylene copolymers; polymethylpentene; polyvinyl chloride; polyvinylidene chloride; polyvinyl acetate; ethylene-vinyl acetate copolymers; polyvinyl alcohol; polyacetal; polyethylene terephthalate; polybutylene terephthalate; polyethylene naphthalate; polystyrene; and polyacrylonitrile. Examples include: styrene-acrylonitrile copolymer; acrylonitrile-butadiene copolymer (nitrile rubber); acrylonitrile-butadiene-styrene copolymer (ABS resin); styrene-butadiene block copolymer or its hydrogenated product; styrene-isoprene block copolymer or its hydrogenated product; polyphenylene ether; modified polyphenylene ether; aliphatic polyamides; aromatic polyamides; polyamide-imide; polycarbonate; polyphenylene sulfide; polysulfone; polyethersulfone; polyethernitrile; polyether ketone; polyketone; polyurethane; liquid crystal polymer; ionomer; and others. These may be used individually or in combination of two or more. In this invention, rubber is included in the term "resin".

[0036] {A thermosetting resin that is solid at room temperature and atmospheric pressure} Examples of thermosetting resins that are solid at room temperature and pressure include natural rubber, butadiene rubber, isoprene rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, ethylene propylene rubber, chlorinated polyethylene, chlorosulfonated polyethylene, butyl rubber, halogenated butyl rubber, polyisobutylene rubber, epoxy resin, polyimide resin, bismaleimide resin, benzocyclobutene resin, phenolic resin, unsaturated polyester, diallyl phthalate resin, polyimide silicone resin, polyurethane, thermosetting polyphenylene ether, thermosetting modified polyphenylene ether, and the like. These may be used individually or in combination of two or more.

[0037] [Resin content] The resin content in the resin sheet is not particularly limited, but is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, preferably 95% by mass or less, more preferably 85% by mass or less, and even more preferably 75% by mass or less. If the resin content is above the lower limit, the formation of the resin sheet becomes easier. On the other hand, if the resin content is below the upper limit, the thermal resistance of the resin sheet can be reduced.

[0038] [Percentage of liquid resin content] Furthermore, the proportion of liquid resin in the resin (in other words, the proportion of liquid resin in the total of solid resin and liquid resin) is not particularly limited, but is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, particularly preferably 60% by mass or more, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. If the proportion of liquid resin in the resin is above the lower limit, the flexibility of the resin sheet can be increased while further reducing the thickness and thermal resistance of the resin sheet. On the other hand, if the proportion of liquid resin in the resin is below the upper limit, the resin molded article becomes easier to slice, and the uniformity of the thickness of the resulting resin sheet can be improved. In addition, the tensile strength of the sheet can be increased.

[0039] <<Thermal conductive filler>> The resin molded article contains an oriented thermal conductive filler. The thermal conductive filler imparts excellent thermal conductivity to the resin sheet. Furthermore, the thermal conductive filler is not particularly limited, and any known thermal conductive filler can be used.

[0040] The orientation angle of the thermal conductive filler is not particularly limited. For example, the angle of the thermal conductive filler with respect to the main surface (surfaces X and Y) of the resin molded body or the main surface of the resin sheet may be between 30° and 90°.

[0041] Furthermore, suitable thermal conductive fillers include, for example, particulate carbon materials and plate-like boron nitride.

[0042] [Particulate carbon material] The particulate carbon material is not particularly limited, and examples of graphite such as artificial graphite, flake graphite, flaked graphite, natural graphite, acid-treated graphite, expandable graphite, and expanded graphite; carbon black; etc. may be used. These may be used individually or in combination of two or more.

[0043] Among the above, expanded graphite is preferred as the particulate carbon material. By using expanded graphite, the thermal resistance of the resin sheet can be further reduced. Expanded graphite can be obtained, for example, by chemically treating graphite such as flake graphite with sulfuric acid to obtain expandable graphite, which is then heat-treated to expand it and then refined. Examples of expanded graphite include EC1500, EC1000, EC500, EC300, EC100, and EC50 (all are product names) manufactured by Ito Graphite Industries Co., Ltd.

[0044] The particulate carbon material preferably has a volume-average particle diameter of 10 μm or more, more preferably 15 μm or more, preferably 150 μm or less, more preferably 100 μm or less, even more preferably 80 μm or less, and particularly preferably 60 μm or less. If the volume-average particle diameter of the particulate carbon material is above the lower limit, it is presumed that a good heat transfer path can be formed in the resin sheet, and the thermal conductivity in the thickness direction of the resin sheet increases. As a result, the thermal resistance of the resin sheet can be further reduced. On the other hand, if the volume-average particle diameter of the particulate carbon material is below the upper limit, the thickness of the resin sheet can be further reduced. In this invention, the "volume-average particle diameter" can be determined using a laser diffraction / scattering particle diameter distribution analyzer, specifically as the particle diameter (D50) at which the cumulative volume calculated from the smallest diameter side reaches 50% in the particle diameter distribution measured using the laser diffraction method.

[0045] Furthermore, the particulate carbon material preferably has an aspect ratio (major axis / minor axis) greater than 1 and less than or equal to 10, and more preferably greater than 1 and less than or equal to 5. It is presumed that when the aspect ratio of the particulate carbon material is within the above range, the particulate carbon material is more likely to be well oriented in the thickness direction within the resin sheet, which increases the thermal conductivity of the resin sheet in the thickness direction. As a result, the thermal resistance of the resin sheet can be further reduced. In this invention, the "aspect ratio" can be determined by observing particulate carbon material with a scanning electron microscope (SEM), measuring the maximum diameter (major diameter) and the particle diameter in the direction perpendicular to the maximum diameter (minor diameter) for any 50 particulate carbon materials, and calculating the average value of the ratio of major diameter to minor diameter (major diameter / minor diameter).

[0046] [Boron Nitride Plates] In this specification, plate-like boron nitride refers to boron nitride particles with an aspect ratio (major axis / minor axis) of 1.4 or greater. The plate-shaped boron nitride particles preferably have an aspect ratio of 10.0 or less, and more preferably 5.0 or less. It is presumed that an aspect ratio of 10.0 or less makes it easier for the plate-shaped boron nitride particles to orient well in the thickness direction within the resin sheet, thereby improving the thermal conductivity of the resin sheet in the thickness direction. Furthermore, flake-shaped boron nitride can be suitably used as the plate-shaped boron nitride. There is no particular lower limit to the aspect ratio, but it is preferably 1.1 or more. In this invention, the "aspect ratio" can be determined by observing boron nitride particles with a scanning electron microscope (SEM), measuring the maximum diameter (major axis) and the particle diameter in the direction perpendicular to the maximum diameter (minor axis) for any 50 boron nitride particles, and calculating the average value of the ratio of major axis to minor axis (major axis / minor axis). In the above, for example, if the plate-like boron nitride particles are scale-shaped, the "major axis" refers to the length in the direction of the major axis of the main surface of the scale-shaped particle, and the "minor axis" refers to the length in the direction perpendicular to the major axis of the main surface.

[0047] The volume-average particle diameter of the plate-shaped boron nitride particles is preferably 10 μm or more, preferably 20 μm or more, more preferably 30 μm or more, preferably 60 μm or less, and more preferably 50 μm or less. If the volume-average particle diameter of the plate-shaped boron nitride particles is above the lower limit, it is presumed that good heat transfer paths can be formed in the resin sheet, thereby improving the thermal conductivity of the resin sheet. On the other hand, if the volume-average particle diameter of the plate-shaped boron nitride particles is below the upper limit, a sufficiently high thickness accuracy of the resin sheet can be ensured. Furthermore, if the volume-average particle diameter of the plate-shaped boron nitride particles is within the above predetermined range, the thermal conductivity of the resin sheet can be further improved. In this invention, "volume-average particle diameter" can be measured in accordance with JIS Z8825 and represents the particle diameter at which the cumulative volume calculated from the smallest diameter side accounts for 50% of the particle size distribution (volume-based) measured by laser diffraction. Furthermore, it is known that there is virtually no discrepancy between the particle size of plate-like boron nitride particles at the material stage and the particle size at the stage where they are contained in the resin sheet after the manufacturing process. Therefore, if the particle size of plate-like boron nitride particles at the material stage is within the above range, it can be inferred that the particle size of plate-like boron nitride particles in the resin sheet is also within the above range.

[0048] [Percentage of thermal conductive filler content] The content ratio of thermal conductive filler in the resin sheet is not particularly limited, but is preferably 30% by volume or more, more preferably 35% by volume or more, particularly preferably 38% by volume or more, preferably 70% by volume or less, and more preferably 60% by volume or less, relative to the total volume of the resin sheet. If the content ratio of thermal conductive filler is above the lower limit, the thermal conductivity in the thickness direction of the thermal conductive filler increases, and the thermal resistance value of the resin sheet can be further reduced. On the other hand, if the content ratio of thermal conductive filler is below the upper limit, the flexibility of the resin sheet and the thickness accuracy of the resin sheet can be improved.

[0049] <<Other ingredients>> The resin sheet of the present invention may further contain known additives that can be used in the formation of the resin sheet, as needed. The additives that can be incorporated into the resin sheet are not particularly limited, but include, for example, plasticizers such as fatty acid esters like sebacate; flame retardants such as red phosphorus-based flame retardants and phosphate ester-based flame retardants; toughness modifiers such as urethane acrylate; hygroscopic agents such as calcium oxide and magnesium oxide; adhesion enhancers such as silane coupling agents, titanium coupling agents, and acid anhydrides; wettability enhancers such as nonionic surfactants and fluorinated surfactants; ion trapping agents such as inorganic ion exchangers; and anti-aging agents such as phenolic antioxidants. Note that one additive may be used alone, or two or more may be used in combination.

[0050] Furthermore, if the resin sheet contains additives, the amount of additives can be, for example, 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the resin described above, and is preferably 10 parts by mass or less.

[0051] <Manufacturing process for resin molded products> A resin molded article can be efficiently manufactured by first forming a pre-resin sheet by pressurizing a composition containing resin and a heat-conducting filler, then laminating multiple pre-resin sheets in the thickness direction, or by folding or winding the pre-resin sheets to form a laminate. However, the resin molded article is not limited to this process; for example, it can also be manufactured by preparing a composition containing resin and a heat-conducting filler, and then applying a magnetic field to orient the heat-conducting filler while the composition is housed in a mold or the like. Below, as an example, the manufacturing of a resin molded article via the former manufacturing process will be described.

[0052] First, a composition containing a resin and a thermal conductive filler, and optionally further containing additives, is pressurized and molded into a sheet to obtain a pre-resin sheet. The resin, thermal conductive filler, and additives described above can be used. The composition is not particularly limited and can be prepared by mixing the above-mentioned components according to known methods. The composition prepared as described above can be optionally degassed and crushed, and then pressurized and molded into a sheet. A sheet formed by pressurizing the composition in this way can be called a pre-resin sheet. In a pre-resin sheet formed by pressurizing the composition into a sheet, the thermal conductive filler is mainly oriented in the in-plane direction, and it is presumed that the thermal conductivity of the pre-resin sheet in the in-plane direction is particularly improved.

[0053] Then, multiple pre-resin sheets obtained above are laminated in the thickness direction, or the pre-resin sheets are folded or wound according to a known method to obtain a laminate in which multiple pre-resin sheets containing resin and thermal conductive filler are formed in the thickness direction. It is presumed that in the laminate obtained by laminating, folding, or winding the pre-resin sheets, the thermal conductive filler is oriented in a direction substantially perpendicular to the lamination direction.

[0054] <Start process> In the initial step, the resin molded body is held by a movable holding device and positioned at the slicing start position, and further, the surface X is kept in a non-contact state. Specifically, in the initial step, as shown in Figure 1, the resin molded body 1 is held by the holding device 20, lifted from the support base 12, and brought into contact with the slicing blade 11.

[0055] Here, the chuck load applied to the resin molded body by the support members 21-23 is preferably 200N or more, more preferably 300N or more, and usually 400N or less. If the chuck load is above the above lower limit, the resin molded body 1 can be held with sufficient strength.

[0056] Furthermore, as shown in Figure 1, in the manufacturing method of the present invention, it is preferable that the holding device 20 holds at least a portion of all surfaces other than surface X and surface Y that constitute the resin molded body 1. This is because the resin molded body 1 can be held with sufficient strength.

[0057] The holding device, as shown in Figure 1, comprises a plurality of support members that hold at least four faces of the resin molded body 1. When the resin molded body 1 is a rectangular parallelepiped, the bottom surface of the rectangular parallelepiped is called surface X, and the top surface is called surface Y. For all faces other than surfaces X and Y that constitute the rectangular parallelepiped, the sides perpendicular to the height direction of the resin molded body 1 are referred to as transverse sides, and it is preferable that all faces other than surfaces X and Y are held by support members 21 to 23, each having a length of 80% or more of the length of the transverse side on each face. This point will be explained in more detail with reference to Figure 3.

[0058] Figure 3 is a schematic diagram illustrating a state in which the resin molded body 1 is held by the supporting members 21 to 23. For clarity, the upper portions of the resin molded body 1 and the supporting member 23 are not shown, and they are illustrated from the height direction to the midway point. The supporting member 21 is disposed on the surface D of the resin molded body. Further, the supporting member 22 is disposed on the surface C. Furthermore, the surface B and the back surface A not shown in Figure 3 are supported by the L-shaped supporting member 23. These members hold the resin molded body 1 by applying an appropriate chuck load. When the length of the lateral side of the surface C is defined as Lp, the length Lq of the lateral side of the supporting member 22 is preferably 80% or more of Lp, more preferably 85% or more, and the upper limit is not particularly limited, and may exceed 100% or may be 95% or less. The same applies to the supporting members 21 and 23. When the relationship between the length of the lateral side of the supporting member and the length of the lateral side of the resin molded body 1 is equal to or more than the above lower limit value, the thickness accuracy of the obtained resin sheet can be further enhanced. In particular, as shown in Figure 4, on the surface D which is the surface of the resin molded body 1 facing the slicing blade 11 and the surface C adjacent to the surface D, the relationship of Lq < Lp holds, and on the surface B which is the surface located on the rear side with respect to the moving direction of the resin molded body 1 in the slicing step and the surface A adjacent to the surface B, the relationship of Lq > Lp preferably holds. This is because the thickness accuracy of the resin sheet can be further efficiently enhanced.

[0059] Furthermore, the protrusion amount L1 of the resin molded body 1 on the surface X side from the holding device 20 is preferably 8 mm or more, more preferably 11 mm or more, preferably 50 mm or less, more preferably 40 mm or less, and even more preferably 25 mm or less. When the protrusion amount L1 is equal to or more than the above lower limit value, it is possible to prevent the cycle for re-holding the resin molded body 1 from becoming excessively short when the slicing step is continuously performed, and to further enhance the production efficiency of the resin sheet. In addition, when the protrusion amount L1 is equal to or less than the above upper limit value, the thickness accuracy of the resin sheet can be further enhanced.

[0060] <Movement step> In the moving process, the resin molded body 1 is moved toward the slicing blade. In the embodiment shown in Figure 1, etc., the resin molded body 1 is moved by the holding device 20. The movement of the resin molded body 1 by the holding device 20 may be a parallel movement in which the resin molded body is moved at a constant height. Furthermore, in the moving process, it is necessary to maintain a non-contact state of the surface X of the resin molded body. This can be achieved by appropriately holding the resin molded body 1 with the holding device 20 and moving it while maintaining a substantially constant position in the height direction.

[0061] <Slicing process> In the slicing process, the resin molded body 1 is sliced ​​into sheets. When slicing the resin molded body 1 with the slicing blade 11, the resin molded body 1 tends to "float" in the surface Y direction during cutting due to the effect of cutting resistance. Therefore, in the slicing process, it is preferable to apply an appropriate load W2 to the resin molded body 1 using the restraining member 31 to prevent such "floating". The value of this load W2 can be appropriately set based on the storage modulus G' of the resin molded body 1. For example, for a resin molded body 1 with a high storage modulus G', it is preferable to apply a higher load W2.

[0062] Here, it is preferable to use the slicing device 100 described with reference to Figure 1 as the cutting tool when slicing the resin molded body 1.

[0063] The slicing speed in the slicing process is preferably 2 m / min or more, more preferably 3 m / min or more, preferably 18 m / min or less, more preferably 12 m / min or less, and even more preferably 9 m / min or less. If the slicing speed is above the lower limit, the manufacturing efficiency of the resin sheet can be further increased, and the difference in tack between the front and back surfaces of the resin sheet can be increased. If the slicing speed is below the upper limit, it is possible to prevent the tack on both the front and back surfaces of the resin sheet from becoming too large.

[0064] The slice thickness in the slicing process is preferably 400 μm or less, more preferably 300 μm or less, and there is no particular lower limit, but it may be 10 μm or more, or 20 μm or more. If the slice thickness is below the above upper limit, the cutting resistance will not increase excessively, and the slicing process can be carried out efficiently while maintaining an appropriate pressure on the slicing blade 11.

[0065] Furthermore, after the nth slicing process, the surface that constituted the surface X of the resin molded body 1 at the start of the nth slicing process is cut off, forming one side of the cut resin sheet. On the other hand, the remaining bottom surface of the resin molded body 1 becomes the new surface X, i.e., the surface X that will be used in the (n+1)th slicing process.

[0066] (Resin sheet) The resin sheet of the present invention is characterized by being free from defects with a depth of 3 μm or more, a width of 100 μm or more, and a length of 1000 μm or more. Here, the resin sheet of the present invention preferably contains resin and oriented thermal conductive filler. The "oriented thermal conductive filler" refers to a thermal conductive filler whose angle with respect to the main surface of the resin sheet is 30° to 90°, as described above.

[0067] Here, the absolute value of the difference in tack force between the two main surfaces of the resin sheet is 1.8 N / cm². 2 Preferably, the above is true. Furthermore, the absolute value of the tack difference is 3.5 N / cm. 2 Preferably, it is 5.0 N / cm² or higher. 2 It is more preferable that the value be greater than or equal to 7.0 N / cm². 2 It is even more preferable that the value be greater than or equal to the above, and the upper limit is not particularly limited, but for example, 30.0 N / cm² 2 It may also be less than 20.0 N / cm². 2 The following conditions may also apply. If the absolute value of the tack difference is greater than or equal to the above lower limit, the reworkability of the resin sheet is excellent.

[0068] Furthermore, in a resin sheet, it is preferable that the tack force of surface S1 is higher than that of surface S2, with the surface roughness Sa and Sz being lower on both of the two main surfaces designated as surface S1 and the other surface as surface S2. Applying this to resin sheet 2 as explained with reference to Figure 2A, it means that it is preferable that the surface roughness Sa and Sz of surface S2, which has a lower tack force, are both higher than that of surface roughness Sa and Sz of surface S1. A resin sheet that satisfies these attributes has the characteristic that the surface with a rougher surface and relatively poor adhesion has a low tack force, and that this surface is relatively easy to peel off from the adherend. Therefore, such a resin sheet has excellent reworkability.

[0069] Furthermore, the surface roughness Sa of the resin sheet is preferably 6.0 μm or less, more preferably 4.0 μm or less, even more preferably 2.0 μm or less, and particularly preferably 1.7 μm or less on the main surface with the lower roughness, i.e., surface S1 as described above. The lower limit is not particularly limited, but may be, for example, 0.8 μm or more, or 1.0 μm or more. If the surface roughness Sa on surface S1 is below the above upper limit, adhesion to the adherend can be improved and thermal conductivity can be improved. Also, on the main surface of the resin sheet with the higher surface roughness Sa, i.e., surface S2, the surface roughness Sa is preferably 1.4 μm or more, more preferably 1.8 μm or more. The upper limit is not particularly limited, but may be 6.0 μm or less, or 5.0 μm or less. If the surface roughness Sa on surface S2 is above the above lower limit, reworkability can be effectively improved.

[0070] Furthermore, the surface roughness Sz of the resin sheet on the lower main surface, i.e., surface S1 as described above, is preferably 36.0 μm or less, more preferably 30.0 μm or less, and even more preferably 25.0 μm or less. The lower limit is not particularly limited, but may be, for example, 10.0 μm or more, or 12.0 μm or more. If the surface roughness Sz on surface S1 is below the above upper limit, adhesion to the adherend can be improved and thermal conductivity can be improved. Furthermore, on the main surface of the resin sheet with a higher surface roughness Sz, i.e., surface S2, the surface roughness Sz is preferably 8.0 μm or more, more preferably 15.0 μm or more, and even more preferably 30.0 μm or more. The upper limit is not particularly limited, but may be 90.0 μm or less, or 80.0 μm or less. If the surface roughness Sz on surface S2 is above the above lower limit, reworkability can be effectively improved.

[0071] Furthermore, surfaces S2 and S1 may be distinguishable by their appearance. For example, surface S2, which has higher surface roughness Sa and Sz, may exhibit a matte texture compared to surface S1. Because they exhibit different textures in appearance, being able to determine which surface has high / low tack strength from its appearance can contribute to improving convenience when mounting resin sheets. [Examples]

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" refers to "parts by mass." In addition, the various measurements and evaluations in the examples and comparative examples were carried out as follows.

[0073] <Tackiness> The tack force of the resin sheet was measured using a probe tack tester (manufactured by Resca Co., Ltd., product name "TAC1000") at a temperature of 25°C. A φ4mm punched resin sheet was attached to the tip of a φ5mm flat circular probe using double-sided tape (Nichiban Co., Ltd. Nicetack NW-15S) on a Si wafer placed on a stage. A load of 0.3 MPa was applied for 10 seconds, and the force required to pull the probe with the resin sheet attached away from the Si wafer was measured.

[0074] <Storage modulus G'> The storage modulus of a resin molded body is calculated by stacking multiple pieces punched out with a 40mm diameter punch, resulting in approximately 5000mm. 3 A sample was prepared. Using a rubber processability analyzer (Alpha Technologies, "Premier® RPA"), the storage modulus was measured under the conditions of temperature: 40°C, frequency: 1 Hz, and strain: 1%, and was used as the storage modulus of the resin molded product.

[0075] <Film thickness of resin sheet> Using a film thickness gauge (Mitutoyo, product name "Digimatic Indicator ID-C112XBS"), the thickness of the resin sheet was measured at a total of nine points, including the approximate center point, the four corners, and the midpoints of each side. The average value (μm) of the measured thicknesses was then calculated.

[0076] <Thickness accuracy of resin sheets> The thickness accuracy of the resin sheet was evaluated based on the standard deviation of the sheet thickness. Using a film thickness gauge (Mitutoyo, product name "Digimatic Indicator ID-C112XBS"), the thickness was measured at a total of nine points, including the approximate center point, the four corners, and the midpoints of each side of the resin sheet, and the standard deviation (μm) of the measured thickness was calculated.

[0077] <Surface roughness of resin sheet Sa, Sz> The surface roughness Sa of the resin sheet was measured for various surfaces using a three-dimensional shape measuring machine (manufactured by Keyence Corporation, product name "One Shot 3D Measurement Macroscope"). Here, resin sheets cut into approximately squares of any size (1 cm x 1 cm or larger) were used as samples, and the analysis range was set to 1 cm x 1 cm. The three-dimensional shape was measured for both the front and back main surfaces of the sample. The three-dimensional shape measurement results were then further filtered (2.5 mm) using software to remove waviness components, and the surface roughness Sa (μm) and Sz (μm) were automatically calculated. Note that surface roughness Sa represents the average value of the height difference from the average surface. Furthermore, surface roughness Sz refers to the distance from the highest point to the lowest point on the surface. The measurement surface, surface S1 of the resin sheet, is the surface that comes into contact with the rake face of the slicing blade during the slicing process and is affected by a relatively small frictional force. On the other hand, surface S2 of the resin sheet is the surface that comes into contact with the relief face of the slicing blade when cutting out the previous resin sheet during the slicing process and is affected by a relatively high frictional force.

[0078] <Density of scratches on resin sheets> The obtained resin sheet (150 mm × 150 mm × 0.06 mm) was placed on an inspection stage (a 200 mm × 200 mm transparent acrylic plate), and light was irradiated from an irradiation angle of 40° relative to the normal to the surface of the resin sheet (50° relative to the surface of the resin sheet) using a white LED bar illuminator (model number "LDL2-275X" manufactured by CCS Inc.; color temperature 7,800 K; power consumption 27 W). Then, while irradiating light, an 8K monochrome CMOS line camera (manufactured by Basler AG; model number "raL8192-12gm"; 8192 pix × 1 pix) installed directly above the resin sheet (that is, at an imaging angle of 90° relative to the surface of the resin sheet) and the white LED bar illuminator were scanned parallel to the surface of the resin sheet, and the surface of the resin sheet was photographed with the camera to obtain a digital image of the surface of the resin sheet. Thereafter, the digital image was subjected to image processing such as smoothing processing and edge detection in an image processing unit (original software) to detect scratches, and the number, width, length, and position coordinates of the scratches were obtained. Next, the inspected resin sheet was taken out from the inspection stage and placed on the stage of a 3D shape measuring instrument (manufactured by Keyence Corporation, product name "VR-6000"). A profile in the depth direction of the scratch was obtained at a magnification of 12 times at the location corresponding to the position coordinates of the scratch obtained in the above inspection. The height of the scratch was measured from the obtained profile. From the obtained width, length, and height of the scratches, the number of scratches having a height of 3 μm or more, a width of 100 μm or more, and a length of 1000 μm or more was calculated, and from the size of the resin sheet for which the number of scratches was inspected, 10000 mm 2 The number of scratches per unit area was calculated and defined as the scratch density.

[0079] (Example 1) <Preparation of Composition> 70 parts of liquid acrylic resin (manufactured by Toagosei Co., Ltd., product name "ARUFON UH-2190"), 30 parts of solid acrylic resin (manufactured by Nippon Zeon Co., Ltd., product name "Nipol H570"), and 145 parts of expanded graphite as a heat conductive filler (manufactured by Ito Graphite Industry Co., Ltd., product name "EC-300", volume average particle size: 50 μm) were mixed and stirred for 5 minutes using a Hobart mixer (manufactured by Kodaira Seisakusho Co., Ltd., product name "ACM-5LVT type"). The resulting mixture was degassed under vacuum for 30 minutes and then placed in a crusher and crushed for 10 seconds to obtain the composition. The resin type used in this example is indicated as "Acrylic 1" in Table 1.

[0080] <Creation of resin molded products> Next, 7 kg of the obtained composition was sandwiched between 100 μm thick PET film (protective film) that had been treated for release, and rolled (primary pressurized) under the conditions of a roll gap of 700 μm, roll temperature of 70°C, roll linear pressure of 1500 N / cm, and roll speed of 1 m / min to obtain a primary sheet with a thickness of 800 μm. Furthermore, the obtained primary sheet was cut to 150 mm in length × 150 mm in width × 800 μm in thickness, and 200 sheets were stacked in the thickness direction of the primary sheet. Finally, a resin molded body with a height of approximately 160 mm was obtained by pressing in the stacking direction for 90 minutes at a temperature of 25°C and a pressure of 1.5 MPa.

[0081] <Start process> The resin molded body obtained above was sliced ​​using a slicing device 100 that satisfies the structure shown in Figure 1. Prior to this, the resin molded body was first held by a chuck, which is a support member, with the holding load shown in Table 1, and placed in the starting position. The size of the two non-L-shaped chucks was 40 mm in height and 134 mm in width. The width of the L-shaped support member was 150 mm each. Therefore, as explained with reference to Figure 4, surfaces C and D of the resin molded body 1 were supported by support members having a width of 134 mm, which is 89% of the width of 150 mm. As explained with reference to Figure 4, surfaces A and B of the resin molded body 1 were supported by support members having a length of 150 mm, which is 100% of the width of 150 mm. In addition, in the starting step, the bottom surface of the resin molded body (surface X as described above) was kept in a non-contact state. Furthermore, the resin molded body was held by the chuck so that the amount L1 of the resin molded body protruding from the holding device was as shown in Table 1.

[0082] <Moving process> During the moving process, the molded resin body was moved towards the slicing blade. A double-edged slicing blade was used, and the relief angle and rake angle were as shown in Table 1. Throughout the moving process, the bottom surface of the molded resin body remained in a non-contact state.

[0083] <Slicing process> In the slicing process, the resin molded body was sliced ​​using a slicing blade. During slicing, the resin molded body was pressed downwards with a 400N load via a holding member from the top surface (i.e., the Y surface as described above) to prevent "lifting" during slicing. At a temperature of 15°C in the processing space, slicing was performed at a speed of 5 m / min at a 90° angle to the lamination direction (in other words, perpendicular to the normal to the main surface of the laminated primary sheet), resulting in a resin sheet measuring 150 mm in length, 150 mm in width, and 60 μm in thickness. Even during slicing, the surface X of the resin molded body was kept in a non-contact state. Then, the obtained resin sheets were subjected to various measurements and evaluations according to the method described above. The results are shown in Table 1.

[0084] (Example 2) Except for changing the holding load and restraining load in the <starting process> as shown in Table 1, the same operations, measurements, and evaluations as in Example 1 were performed. The results are shown in Table 1.

[0085] (Examples 3-5) Except for changing the amount L1 of the resin molded body protruding from the holding device in the <starting step> so that it is as shown in Table 1, various operations, measurements, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0086] (Example 6) Except for using a slicing blade with the relief angle and rake angle shown in Table 1 (a slicing blade with a large rake angle was used), the same operations, measurements, and evaluations as in Example 1 were performed. The results are shown in Table 1.

[0087] (Example 7) In the <Composition Preparation> step, the resins used were 37 parts of liquid acrylic resin (manufactured by Toagosei Co., Ltd., trade name "ARUFON(registered trademark) UH-2190") at room temperature and atmospheric pressure, 39 parts of liquid thermoplastic fluororesin (manufactured by Daikin Industries, Ltd., trade name "Daiel G-101") at room temperature and atmospheric pressure, and 24 parts of solid thermoplastic fluororesin (manufactured by 3M Japan Limited, trade name "Dinion FC2211") at room temperature and atmospheric pressure. The amount of expanded graphite (manufactured by Ito Graphite Industry Co., Ltd., trade name "EC-300", volume average particle size: 50 μm), which is a thermal conductive filler, was changed to 98 parts. Furthermore, in the <Slicing Step>, the slice thickness was changed as shown in Table 1. Except for these points, various operations, measurements, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1. The resin types used in this example are referred to as "Fluorine-Acrylic Mixture" in Table 1.

[0088] (Example 8) In the <Composition Preparation> step, the resins used were changed to 30 parts of liquid acrylic resin (manufactured by Toagosei Co., Ltd., product name "ARUFON UH-2190") and 70 parts of solid acrylic resin (manufactured by Nippon Zeon Co., Ltd., product name "Nipol H570") at room temperature and atmospheric pressure (these resin types are indicated as "Acrylic 2" in Table 1). Furthermore, the thermal conductive filler was changed from expanded graphite to 310 parts of plate-shaped boron nitride (HSPD50, average particle size 50 μm, aspect ratio 75, manufactured by Dandong Chemical Engineering Institute). In addition, in the <Starting Step>, the amount L1 of the resin molded body protruding from the holding device was changed to that shown in Table 1. Then, in the <Slicing Step>, the slicing speed and slice thickness were changed as shown in Table 1. Except for these points, various operations, measurements, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0089] (Example 9) In the <Composition Preparation> step, the resin used was changed to 70 parts of liquid thermoplastic fluororesin (manufactured by Daikin Industries, Ltd., product name "Daiel G-101") and 30 parts of solid thermoplastic fluororesin (manufactured by 3M Japan Limited, product name "Dinion FC2211") at room temperature and atmospheric pressure. In addition, the amount of expanded graphite used as a thermal conductive filler was changed to 90 parts. Furthermore, in the <Starting Step>, the amount L1 of the resin molded body protruding from the holding device was changed to that shown in Table 1. Then, in the <Slicing Step>, the slice thickness was changed as shown in Table 1. Except for these points, various operations, measurements, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1. The resin type used in this example is indicated as "Fluorine-based" in Table 1.

[0090] (Examples 10-11) Except for using a slicing blade with the relief angle and rake angle shown in Table 1 (a slicing blade with a large rake angle was used) and changing the slicing speed in the <slicing process> as shown in Table 1, the same operations, measurements, and evaluations as in Example 1 were performed. The results are shown in Table 1.

[0091] (Comparative Example 1) Unlike Example 1, the <starting step>, <moving step>, and <slicing step>, in which the surface X of the resin molded body is kept in a non-contact state, were not performed. Instead, the side surface of the resin molded body (the surface along the lamination direction) was pressed with a load of 240N, and a woodworking slicer (manufactured by Marunaka Iron Works Co., Ltd., product name "Super Mecha S Super Finishing Planer", equipped with the same slicing blade as in Example 1) was used to ensure that the amount of the resin molded body protruding from the holding device was 25mm, with the temperature in the processing space of the slicer at 15°C. The resin molded body was then sliced ​​at a speed of 6mm / second at a 90° angle to the lamination direction (in other words, perpendicular to the normal of the main surface of the laminated primary sheet), obtaining a resin sheet with dimensions of 150mm (length) x 150mm (width) x 62μm (thickness). The obtained resin sheet was subjected to the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0092] (Comparative Example 2) Except for using a slicing blade with the relief angle and rake angle shown in Table 1 (a slicing blade with a large rake angle was used), the same operations, measurements, and evaluations as in Comparative Example 1 were performed. The results are shown in Table 1.

[0093] [Table 1]

[0094] Table 1 shows that the resin sheets obtained according to the manufacturing methods of Examples 1 to 11 were free of scratches. On the other hand, scratches were found in the resin sheets obtained according to the manufacturing methods of Comparative Examples 1 to 2, in which the surface X of the resin molded body was not kept in a non-contact state during slicing, etc. [Industrial applicability]

[0095] According to the present invention, it is possible to provide a method for manufacturing a resin sheet that can suppress the occurrence of scratches. [Explanation of Symbols]

[0096] 1. Resin molded body 2 Resin sheet 10. Blade holder 11 slicing blades 11a Relief surface of the slicing blade 11b Slicing blade rake face 12 Support stand 20 Holding device 21-23 Support members 100-slice machine A-D Side view of the resin molded product D1 Distance between the support base and the holding device H1 Slicing blade height L1 Protrusion amount of resin molded body Length of the transverse side of the Lp resin molded body Lq: Length of the horizontal side of the support member S1, S2 resin sheet surface X, Y Upper and lower surfaces of the resin molded body

Claims

1. A method for manufacturing a resin sheet, comprising slicing a resin molded body having a shape in which surfaces X and Y are arranged at a distance equal to the height of the resin molded body by moving it in a transverse direction relative to the height direction of the resin molded body toward a slicing blade fixed to a blade fixing base, Of the aforementioned surfaces X and Y, the surface closer to the slicing blade is referred to as surface X. The resin molded body is held by a movable holding device and placed at the slicing start position, and the starting step is to ensure that the surface X is in a non-contact state. After the aforementioned starting step, a moving step is performed to move the resin molded body toward the slicing blade, The process includes a slicing step of slicing the resin molded body into a sheet, In the aforementioned transfer step, the non-contact state of the surface X of the resin molded body is maintained. Method for manufacturing resin sheets.

2. The resin sheet manufacturing method according to claim 1, wherein the resin molded article comprises a resin and an oriented thermal conductive filler.

3. The method for manufacturing a resin sheet according to claim 1, wherein the storage modulus G' of the resin molded article at 40°C is 1,000 kPa or more and 12,000 kPa or less.

4. The resin sheet manufacturing method according to claim 1, wherein the holding device holds at least a portion of all surfaces other than surface X and surface Y that constitute the resin molded body.

5. The resin molded body is a rectangular parallelepiped, The holding device comprises a plurality of support members that hold at least four sides of the resin molded body, When the lower surface of the rectangular parallelepiped is designated as surface X and the upper surface as surface Y, all surfaces other than surfaces X and Y that constitute the rectangular parallelepiped are defined as horizontal sides, where the sides perpendicular to the height direction of the resin molded body are referred to as horizontal sides. In the aforementioned starting step, all surfaces other than surfaces X and Y are held by one of the plurality of support members, each having a length of 80% or more of the length of the transverse side of each surface. The method for manufacturing a resin sheet according to claim 1.

6. The resin sheet manufacturing method according to claim 1, wherein the amount of protrusion from the holding device on the surface X side of the resin molded body is 8 mm or more and 50 mm or less.

7. A method for manufacturing a resin sheet according to any one of claims 1 to 6, wherein the relief angle of the slicing blade is greater than 0° and 8° or less, and the rake angle of the slicing blade is 60° or more and 70° or less.

8. A resin sheet free of scratches with a height of 3 μm or more, a width of 100 μm or more, and a length of 1000 μm or more.

9. The resin sheet according to claim 8, comprising a resin and an oriented thermal conductive filler.

10. The absolute value of the difference in tack force between the two main surfaces of the aforementioned resin sheet is 1.8 N / cm. ２ The resin sheet according to claim 8.

11. The resin sheet according to any one of claims 8 to 10, wherein of the two main surfaces of the resin sheet, the surface with both low surface roughness Sa and Sz is designated as surface S1, and the other surface is designated as surface S2, and the tack force of surface S1 is higher than the tack force of surface S2.

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