KR102602785B1 - Manufacturing Method of Thermally Conductive Sheet using Comma Coater - Google Patents

Abstract

The present invention relates to a method of manufacturing a thermally conductive sheet using a comma coating machine, wherein a thermally conductive composition containing a polymer, an anisotropic thermally conductive filler, and a filler is applied to a comma coating machine including a coating roller rotating along a first central axis and a comma member. By adding the anisotropic thermally conductive filler to orient the anisotropic thermally conductive filler along a second central axis that intersects the first central axis, to obtain a sheet-shaped primary preform extending along the second central axis and having a predetermined thickness. Comma forming process; A stacking process of obtaining a laminated molded product by stacking a plurality of the primary preforms in the thickness direction; A press molding process of obtaining a secondary preform in which the anisotropic heat conductive filler of the laminated molded product is oriented in a direction intersecting the thickness direction by pressing the laminated molded product along the thickness direction of the laminated molded product using a press molding machine; A curing process of obtaining a cured molded product by curing the secondary preform; and a cutting process of cutting the cured molded product in a cutting direction that intersects the second central axis to have a predetermined thickness.
According to the present invention, unlike the conventional manufacturing method in which the diameter of the sheet base material is limited due to the limitations of extrusion molding itself, a large-sized thermal conductive sheet can be manufactured, and mass production is also easy to achieve.

Description

{Manufacturing Method of Thermally Conductive Sheet using Comma Coater}

The present invention relates to a method of manufacturing a thermally conductive sheet, and in particular, to a method of manufacturing a thermally conductive sheet that can produce large-sized thermally conductive sheets in large quantities, unlike conventional manufacturing methods.

In general, electronic products such as computers, portable personal devices, and communication devices are unable to dissipate excessive heat generated inside the system to the outside, raising serious concerns about afterimage problems and system stability. This heat shortens the lifespan of the product, causes failure or malfunction, and in severe cases can even cause explosion or fire, making it important to efficiently dissipate the heat generated from electronic components.

Conventionally, heat dissipation fins, heat dissipation sheets, and heat sinks have been used as a means to efficiently control the generated heat. However, the heat dissipation fins and heat sinks are less efficient because the heat sink can emit less heat than the amount of heat emitted from the heating element of electronic products. This was very low, so there was a problem that a heat dissipation fan had to be installed together.

In particular, the simultaneous installation of heat dissipation fans not only causes problems with noise and vibration generated from the heat dissipation fans, but also has the problem of not being applicable to products that require weight reduction and slimness, so it is recently called heat dissipation. Sheets are widely used.

Heat dissipation sheets used conventionally are a type of thermally conductive sheet, and are widely used in which inorganic fillers such as copper, alumina, ferrite, aluminum nitride, and aluminum hydroxide, which have thermal conductivity, are dispersed in a resin composition.

However, when the content of the inorganic filler is low, these heat dissipation sheets have very low heat conduction, and when the content of the inorganic filler is high, the content of other components is low, which not only reduces the bonding power between the powders, but also reduces the flexibility and formability of the sheet. Not only is this problem of deterioration occurring, but the conventional thermal conductive sheet containing inorganic filler has a very low thermal conductivity of 1.5 to 5 W/m·K even if the content of inorganic filler is increased, making it difficult to dissipate heat efficiently. There was a problem.

Recently, in order to solve the problems of heat dissipation sheets containing the above-described inorganic fillers, heat dissipation sheets with increased thermal conductivity by further containing anisotropic carbon fiber, etc. have been manufactured, and Korean Patent Publication (Publication No. 10- 2013-0117752 (publication date: October 28, 2013) discloses a technology for manufacturing a heat dissipation sheet by forming a sheet base material by extrusion molding and slicing the hardened sheet base material to a predetermined thickness.

However, when the sheet base material formed by extrusion is sliced and manufactured into a heat dissipation sheet, the diameter of the sheet base material is limited due to the limitations of the extrusion molding itself, so large-sized heat dissipation sheets cannot be manufactured and mass production cannot be achieved. There were various problems, including:

The present invention was devised to solve the above problem, and its purpose is to provide an improved method of manufacturing a thermally conductive sheet that can mass-produce large-sized thermally conductive sheets, unlike conventional manufacturing methods.

In order to achieve the above object, the method of manufacturing a thermally conductive sheet according to the present invention includes a thermally conductive composition containing a polymer, an anisotropic thermally conductive filler, and a filler, a coating roller rotating along a first central axis, and a comma member including a comma member. By introducing the anisotropic thermally conductive filler into a coating machine, the anisotropic thermally conductive filler is oriented along a second central axis that intersects the first central axis, and a sheet-shaped primary preform extending along the second central axis and having a predetermined thickness is obtained. comma forming process; A stacking process of obtaining a laminated molded product by stacking a plurality of the primary preforms in the thickness direction; A press molding process of obtaining a secondary preform in which the anisotropic heat conductive filler of the laminated molded product is oriented in a direction intersecting the thickness direction by pressing the laminated molded product along the thickness direction of the laminated molded product using a press molding machine; A curing process of obtaining a cured molded product by curing the secondary preform; and a cutting process of cutting the cured molded product in a cutting direction that intersects the second central axis to have a predetermined thickness.

Here, in the lamination process, it is preferable to obtain the lamination molding product by cutting the primary preform obtained in the comma forming process to a predetermined length and then stacking a plurality of pieces in the thickness direction.

Here, in the lamination process, the lamination molding may be obtained by rolling and stacking the primary preform obtained in the comma forming process multiple times into a roll shape with the first central axis as the center of rotation.

Here, in the press molding process, it is preferable to press the laminated molded product along the thickness direction of the laminated molded product while inserting the laminated molded product into a mold member of a predetermined shape.

Here, the comma member preferably has a forming groove formed by arranging a plurality of unit groove parts extending along the second central axis along the first central axis.

Here, the cross-sectional shape of the unit groove portion is preferably at least one selected from the group including circular, semi-circular, oval, semi-elliptical, square, rectangular, and triangular.

Here, the width of the unit groove portion is preferably 1 to 10 mm.

Here, the forming groove preferably has a width of 10 to 50 cm along the first central axis and a length of 2 to 20 cm along the second central axis.

Here, the polymer preferably contains a silicone resin.

Here, the filler preferably includes at least one of aluminum oxide, aluminum nitride, zinc oxide, silicon powder, and metal powder.

Here, the filler preferably contains spherical aluminum oxide particles with an average particle diameter of 0.1 μm to 45 μm.

Here, the content of the filler in the thermally conductive composition is preferably 20% to 40% by volume.

Here, the content of the anisotropic thermally conductive filler in the thermally conductive composition is preferably 20% to 50% by volume.

Here, the anisotropic thermally conductive filler preferably includes at least one selected from the group including boron nitride (BN) powder, graphite, carbon fiber, and carbon nanotube (Carbon nanotube, CNT).

According to the present invention, a thermally conductive composition containing a polymer, an anisotropic thermally conductive filler, and a filler is introduced into a comma coater including a coating roller rotating along a first central axis and a comma member, thereby forming the anisotropic thermally conductive filler into the first central axis. A comma forming process of obtaining a sheet-shaped primary preform oriented along a second central axis that intersects the first central axis, extending along the second central axis, and having a predetermined thickness; A stacking process of obtaining a laminated molded product by stacking a plurality of the primary preforms in the thickness direction; A press molding process of obtaining a secondary preform in which the anisotropic heat conductive filler of the laminated molded product is oriented in a direction intersecting the thickness direction by pressing the laminated molded product along the thickness direction of the laminated molded product using a press molding machine; A curing process of obtaining a cured molded product by curing the secondary preform; A cutting process of cutting the cured molded product in a cutting direction intersecting the second central axis to have a predetermined thickness; thus, a conventional manufacturing method in which the diameter of the sheet base material is limited due to the limitations of the extrusion molding itself. Unlike, it is possible to manufacture large-sized thermally conductive sheets, and mass production is also easy to achieve.

Figure 1 is a diagram showing a comma coater used to manufacture a thermally conductive sheet according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA of the comma member shown in FIG. 1.
Figure 3 is a plan view of the comma member shown in Figure 1.
FIG. 4 is a diagram showing a state in which a laminated molded product in which a plurality of primary preforms manufactured by the comma coater shown in FIG. 1 are stacked in the thickness direction is mounted on a press molding machine.
FIG. 5 is a diagram illustrating a process of obtaining a secondary preform by pressing the laminated molded product along the thickness direction of the laminated molded product using the press molding machine shown in FIG. 4.
FIG. 6 is a diagram for explaining an example of the cutting process shown in FIG. 10.
FIG. 7 is an enlarged view showing a cross section of a thermally conductive sheet completed through the cutting process shown in FIG. 6.
Figure 8 is a diagram illustrating the process of obtaining a laminated molded product by rolling and stacking the primary preform manufactured by a comma coater multiple times into a roll shape.
FIG. 9 is a diagram illustrating the process of pressing the roll-shaped laminated molded product shown in FIG. 8 while mounted on a press molding machine.
Figure 10 is a diagram for explaining the change in the orientation angle of the anisotropic thermally conductive filler that occurs when performing the main process of the method of manufacturing a thermally conductive sheet according to an embodiment of the present invention.
Figure 11 is a flowchart for explaining a method of manufacturing a thermally conductive sheet according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

Figure 1 is a diagram showing a comma coating machine used to manufacture a thermally conductive sheet according to an embodiment of the present invention, and Figure 2 is a cross-sectional view taken along line A-A of the comma member shown in Figure 1. Figure 3 is a plan view of the comma member shown in Figure 1, and Figure 11 is a flowchart for explaining a method of manufacturing a thermally conductive sheet according to an embodiment of the present invention.

Referring to FIG. 11, the method of manufacturing a thermally conductive sheet according to a preferred embodiment of the present invention involves manufacturing a thermally conductive sheet 100 used to dissipate excessive heat generated from electronic products such as portable personal terminals and communication devices to the outside. The manufacturing method includes a comma forming process (S10), a lamination process (S20), a press forming process (S30), a curing process (S40), and a cutting process (S50).

First, before explaining the processes (S10 to S50) of the method of manufacturing the thermally conductive sheet, the thermal conductive material that is the base material of the comma coater 200 and the thermally conductive sheet 100 shown in FIGS. 1 to 3 The composition (M) will be described first.

As shown in FIG. 1, the comma coater 200 transfers a coating roller 210, a film member 220, a dam member 230, an elevating member 240, and a comma member 250. Includes device 260.

The coating roller 210 is a circular roller that rotates along the first central axis C1, as shown in FIG. 1, and performs the function of transporting the film member 220.

The film member 220 is a sheet member that is transported in close contact with the outer peripheral surface of the coating roller 210, and is the object on which the liquid thermally conductive composition (M) trapped by the dam member 230 is coated.

When the film member 220 is rotated by the coating roller 210 while in contact with the thermally conductive composition (M) accommodated inside the dam member 230, the thermally conductive composition (M) is transferred to the film member. It is coated on the upper surface of (220).

The dam member 230 is a member that forms a space to accommodate the liquid thermally conductive composition (M), as shown in FIG. 1.

In this embodiment, the dam member 230, the comma member 250, and the film member 220 cooperate with each other to form a space for accommodating the thermally conductive composition (M).

The lifting member 240 is a member coupled to one end of the comma member 250 in a non-relatively movable manner, and can be moved up and down by the transfer device 260.

An inclined surface 241 as shown in FIG. 1 is formed at the lower end of the lifting member 240.

The comma member 250 is a member for adjusting the thickness (H) of the thermally conductive composition (M) coated on the upper surface of the film member 220, and is provided as a plate-shaped metal member.

In this embodiment, the comma member 250 extends a predetermined length L along the second central axis C2 perpendicular to the first central axis C1, as shown in FIGS. 1 and 3. It is done.

As shown in FIG. 2, a molding groove 251 of a predetermined shape is formed on the lower surface of the comma member 250.

As shown in FIGS. 2 and 3, the molding groove 251 extends a predetermined length L along the second central axis C2, and is predetermined in the direction of the first central axis C1. It has a fixed width (W).

The forming groove 251 is a tunnel-shaped groove portion whose both ends are open as shown in FIG. 2.

In this embodiment, the forming groove 251 is formed by arranging a plurality of unit groove portions 251a extending along the second central axis C2 along the first central axis C1.

The cross-sectional shape of the unit groove portion 251a may have various shapes such as circular, semicircular, oval, semielliptical, square, rectangular, and triangular, but as shown in FIG. 2, in this embodiment, it is provided in a semicircular shape.

The width of the unit groove portion 251a may have various values, but is preferably 1 to 10 mm.

The forming groove 251 preferably has a width W of 10 to 50 cm along the first central axis C1 and a length of 2 to 20 cm along the second central axis C2.

The transfer device 260 is a device for adjusting the gap between the lower surface of the comma member 250 and the upper surface of the film member 220, and is a device for moving the lifting member 240 up and down.

In this embodiment, the transfer device 260 includes a motor 261, a male member 262, and a female member 263.

The motor 261 is a motor that rotates by electricity and can rotate the male member 262 in both directions.

The male member 262 is a male screw member extending along the second central axis C2 and can be rotated by the motor 261.

The female member 263 is a female screw member screwed to the male member 262, and can be moved left and right along the second central axis C2 when the male member 262 rotates.

The upper end of the arm member 263 is in sliding contact with the inclined surface 241 of the lifting member 240.

Therefore, when the arm member 263 moves left and right along the second central axis C2, the lifting member 240 moves up and down.

The operating principle of the transfer device 260 is substantially similar to the operating principle of a ball screw, which is widely known to those skilled in the art.

The thermally conductive composition (M) contains a polymer (3), an anisotropic thermally conductive filler (1), and a filler (2), as shown in FIG. 10.

The polymer 3 is not particularly limited and can be appropriately selected depending on the performance required for the thermally conductive sheet 100. Examples include thermoplastic polymers or thermosetting polymers.

Examples of the thermoplastic polymer include thermoplastic resins, thermoplastic elastomers, and alloys of these polymers. The thermoplastic resin is not particularly limited and can be appropriately selected depending on the purpose, and examples include ethylene-α-olefin copolymers such as polyethylene, polypropylene, and ethylene-propylene copolymer; Fluorine-based resins such as polymethyl pentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyacetal, polyvinylidene fluoride, and polytetrafluoroethylene; Polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, polyacrylonitrile, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer (ABS) resin, polyphenylene ether, modified poly. Phenylene ether, aliphatic polyamides, aromatic polyamides, polyamidoimide, polymethacrylic acid or its ester, polyacrylic acid or its ester, polycarbonate, polyphenylene sulfide, polysulfone, polyethersulfone, polyethernitrile. , polyether ketone, polyketone, liquid crystal polymer, silicone resin, ionomer, etc. These may be used individually by 1 type, or may use 2 or more types together.

The thermoplastic elastomers include, for example, styrene-based thermoplastic elastomers such as styrene-butadiene copolymer or its hydrogenated polymer, styrene-isoprene block copolymer or its hydrogenated polymer, olefin-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, and polyester-based thermoplastic elastomer. Thermoplastic elastomers, polyurethane-based thermoplastic elastomers, and polyamide-based thermoplastic elastomers may be included. These may be used individually by 1 type, or may use 2 or more types together.

Examples of the thermosetting polymer include crosslinked rubber, epoxy resin, polyimide resin, bismaleimide resin, benzoxychlorbutene resin, phenol resin, unsaturated polyester, diallyl phthalate resin, silicone resin, polyurethane, and polyimide. Silicone, thermosetting polyphenylene ether, thermosetting modified polyphenylene ether, etc. are mentioned. These may be used individually by 1 type, or may use 2 or more types together.

Examples of the cross-linked rubber 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, fluorine rubber, Examples include urethane rubber, acrylic rubber, polyisobutylene rubber, and silicone rubber. These may be used individually by 1 type, or may use 2 or more types together.

Among these, silicone resin is particularly preferable in terms of excellent molding processability and weather resistance, as well as adhesion and followability to electronic components.

The silicone resin is not particularly limited and can be appropriately selected depending on the purpose, and examples include addition reaction type liquid silicone rubber, heat vulcanization type mirrorable type silicone rubber that uses peroxide as vulcanization, and the like. Among these, addition reaction type liquid silicone rubber is particularly preferable as a heat dissipation member for electronic devices because adhesion between the heating surface and the heat sink surface of the electronic component is required.

The shape of the anisotropic thermally conductive filler 1 is not particularly limited and can be appropriately selected depending on the purpose, for example, flake shape, plate shape, column shape, prismatic shape, oval shape, flat shape, etc. . Among these, a flat shape is particularly preferable in terms of anisotropic thermal conductivity.

Examples of the filler having the anisotropy include boron nitride (BN) powder, graphite, carbon fiber, and carbon nanotube (CNT). Among these, carbon fiber is particularly preferable in terms of anisotropic thermal conductivity.

As the carbon fiber, for example, those synthesized by pitch-based, PAN-based, arc discharge method, laser evaporation method, CVD method (chemical vapor growth method), CCVD method (catalytic chemical vapor growth method), etc. can be used. Among these, pitch-based carbon fiber is particularly preferable in terms of thermal conductivity.

The carbon fiber can be used by subjecting part or all of it to surface treatment, if necessary. The surface treatment includes, for example, oxidation treatment, nitridation treatment, nitration, sulfonation, or a functional group introduced to the surface by these treatments, or attaching a metal, metal compound, organic compound, etc. to the surface of the carbon fiber. Or, a combining process may be used. Examples of the functional group include hydroxyl group, carboxyl group, carbonyl group, nitro group, amino group, etc.

The average major axis length (average fiber length) of the carbon fiber is preferably 100 μm or more, and more preferably 120 μm to 6 mm. If the average major axis length is less than 100 μm, sufficient anisotropic thermal conductivity may not be obtained and thermal resistance may increase. The average minor axis length of the carbon fiber is preferably 6 μm to 15 μm, and more preferably 8 μm to 13 μm.

The carbon fiber preferably has an aspect ratio (average major axis length/average minor axis length) of 8 or more, and more preferably 12 to 30. If the aspect ratio is less than 8, the thermal conductivity may decrease because the fiber length (major axis length) of the carbon fiber is short.

The content of the anisotropic thermally conductive filler in the thermally conductive composition is preferably 20% to 50% by volume. Here, if the content is less than 20 volume%, sufficient thermal conductivity may not be provided to the molded article, and if it exceeds 50 volume%, moldability and orientation may be affected.

The filler 2 is not particularly limited in terms of its shape, material, average particle size, etc., and can be appropriately selected depending on the purpose. The shape is not particularly limited and can be appropriately selected depending on the purpose, and examples include spherical shape, elliptical shape, block shape, granular shape, flat shape, and needle shape. Among these, spherical and elliptical shapes are preferable in terms of filling properties, and spherical shapes are particularly preferable.

Examples of the material of the filler 2 include aluminum nitride, silica, alumina, boron nitride, titania, glass, zinc oxide, silicon carbide, silicon powder, silicon oxide, aluminum oxide, metal powder, etc. These may be used individually, or two or more types may be used together. Among these, alumina, boron nitride, aluminum nitride, zinc oxide, and silica are preferable, and alumina and aluminum nitride are particularly preferable in terms of thermal conductivity.

Additionally, the filler 2 may be surface treated. When treated with a coupling agent as the surface treatment, dispersibility is improved and the flexibility of the thermally conductive sheet 100 is improved. Additionally, the surface roughness obtained by cutting can be made smaller.

In this embodiment, the filler 2 contains spherical aluminum oxide particles with an average particle diameter of 0.1 μm to 45 μm. If the average particle diameter is less than 0.1 μm, it may cause curing failure, and if it exceeds 45 μm, the orientation of the carbon fiber may be impaired and the heat conductivity of the cured molded product 10c may be lowered.

In this example, the content of the filler (2) in the thermally conductive composition is 20% to 40% by volume.

The thermal conductive composition may further contain, if necessary, solvents, thixotropic agents, dispersants, curing agents, curing accelerators, retardants, non-tackifiers, plasticizers, flame retardants, antioxidants, stabilizers, colorants, etc. External ingredients can be mixed.

Here, thixotropic is the property of being in a sol (SOL) state close to liquid when flowing and maintaining a gel (GEL) state with increasing viscosity in a stable state. During application, it comes out thin and is applied smoothly. , It is a property that does not flow when applied to the adherend, and is a property that can provide a type of time-dependent viscosity.

The thermally conductive composition can be prepared by mixing the polymer (3), the anisotropic thermally conductive filler (1), the filler (2), and, if necessary, the other components using a mixer or the like.

Below, a detailed description of the manufacturing method of the thermally conductive sheet will be provided.

In the comma forming process (S10), as shown in FIG. 1, the thermally conductive composition (M) is inputted into the comma coater 200 to form a sheet-shaped first preform (10a) with a predetermined thickness (H). ) is the stage of obtaining.

That is, after the thermally conductive composition (M) having a predetermined viscosity is introduced into the dam member 230, the comma coater 200 is operated to form the first preform on the upper surface of the film member 220. This is the process of obtaining (10a).

At this time, inside the primary preform 10a, the anisotropic thermally conductive filler 1, which was randomly oriented, is aligned with the first central axis of the primary preform 10a, as shown in FIG. 10. It is oriented to some extent parallel to the longitudinal direction (C2), which is substantially perpendicular to (C1), and at an angle within a predetermined angle. (Comma forming process: S10)

Next, the primary preform (10a) manufactured in the comma forming process (S10) is cut to a predetermined length, and then stacked in plural pieces in the thickness (H) direction as shown in FIG. 4 to form a laminated molding (S). is obtained.

In this embodiment, as shown in FIG. 4, a plurality of primary preforms 10a cut to a predetermined length are stacked one on another inside the mold member 320 of the press molding machine 300, which will be described later. (Laminating process: S20)

And, as shown in FIG. 4, by lowering the pressing member 310 of the press molding machine 300 along the pressing direction (P), the laminated molding (S) is formed along the thickness (H) direction of the laminated molding (S). ), as shown in Figure 10, the anisotropic thermally conductive filler (1) of the laminated molded product (S) is further aligned with the direction (C2) perpendicular to the thickness (H) direction and within a predetermined angle. An oriented secondary preform (10b) is obtained.

Here, the anisotropic thermally conductive filler 1 present inside the secondary preform 10b has a more improved orientation than the anisotropic thermally conductive filler 1 present inside the primary preform 10a. have it That is, as shown in FIG. 10, the anisotropic heat conductive filler 1 present inside the secondary preform 10b is arranged more parallel to the longitudinal direction C2 of the secondary preform 10b. .

In this embodiment, the press molding machine 300 includes a rectangular pressing member 310 that can descend along the pressing direction (P) or rise in the opposite direction, as shown in FIG. 4, and the pressing member 310 ) and a mold member 320 having a rectangular parallelepiped-shaped internal space of a predetermined shape to correspond to the mold member 320. (Press molding process: S30)

After molding the secondary preform 10b using the press molding machine 300, the secondary preform 10b is cured to form a rectangular parallelepiped-shaped cured molding 10c as shown in FIG. 5. obtain it. At this time, the completed cured molded product 10c can be obtained through an appropriate curing reaction depending on the polymer 3 used.

The method of curing the secondary preform 10b is not particularly limited and can be appropriately selected depending on the purpose. When a thermosetting resin such as a silicone resin is used as the polymer, it is preferable to cure the secondary preform 10b by heating.

Examples of devices used for the heating include a far-infrared furnace and a hot stove. The heating temperature is not particularly limited and can be appropriately selected depending on the purpose; for example, it is preferably carried out at 40°C to 150°C.

The flexibility of the silicone cured molding 10c obtained by curing the silicone resin is not particularly limited and can be appropriately selected depending on the purpose, and can be adjusted by, for example, the crosslink density of the silicone, the amount of heat conductive filler filled, etc. (Curing process; S40)

Subsequently, the cured molded product 10c cured through the curing process (S40) is cut using an ultrasonic cutter 400 as shown in FIG. 6 to have a predetermined thickness t as shown in FIG. 7. The thermally conductive sheet 100 having is completed.

At this time, the blade of the ultrasonic cutter 400 gradually descends while vibrating along the vibration direction (V) substantially perpendicular to the longitudinal direction (C2) of the cured molded product (10c), as shown in FIG. The cured molded product 10c is cut. (Cutting process; S50)

Meanwhile, Figure 8 shows another example of the stacking process (S20). That is, in this embodiment, the primary preform 10a manufactured by the comma coater 200 is not cut to a short length, but is rolled and laminated multiple times in the form of a roll, thereby forming a laminated molded product in the form of a roll. In terms of obtaining (S), the primary preform (10a) is cut relatively short to a predetermined length and then stacked in plural pieces in the thickness (H) direction as shown in FIG. 4 to obtain a laminated molding (S). There is a difference from the lamination process (S20) of obtaining.

As shown in FIG. 9, the roll-shaped laminated molding (S) is stacked one after another inside the mold member 320 of the press molding machine 300. By lowering the pressing member 310 along the pressing direction (P), the lamination molding (S) is pressed along the thickness (H) direction of the lamination molding (S) to obtain the secondary preform (10b). The point is the same as the press forming process (S30) described above.

As in this embodiment, when using a roll-shaped laminated molding (S), the first preform (10a) manufactured by the comma coater 200 is cut into short lengths and then laminated one by one. There is an advantage that the process can be omitted, and a lump-shaped laminated molded product (S) can be easily obtained.

Of course, both ends of the secondary preform (10b) obtained after pressing the roll-shaped laminated product (S) by the press molding machine (300) are anisotropic thermally conductive filler ( Since the orientation of 1) may be poor, it is preferable to remove it prior to the cutting process (S50).

The method for producing a thermally conductive sheet having the above-described configuration involves rotating a thermally conductive composition (M) containing a polymer (3), an anisotropic thermally conductive filler (1), and a filler (2) along the first central axis (C1). By inputting the anisotropic heat conductive filler 1 into the comma coating machine 200 including the coating roller 210 and the comma member 250, the anisotropic heat conductive filler 1 is formed along a second central axis substantially perpendicular to the first central axis C1. A comma forming process (S10) of obtaining a sheet-shaped primary preform (10a) oriented along (C2), extending along the second central axis (C2), and having a predetermined thickness (H); A stacking process (S20) of obtaining a laminated molded product (S) by stacking a plurality of the primary preforms (10a) in the thickness (H) direction; By pressing the lamination molding (S) along the thickness (H) direction of the lamination molding (S) using the press molding machine 300, the anisotropic heat conductive filler (1) of the lamination molding (S) is formed at the thickness ( H) press forming process (S30) to obtain a secondary preform (10b) oriented substantially perpendicular to the direction; A curing process (S40) of obtaining a cured molded product (10c) by curing the secondary preform (10b); Since it includes a cutting process (S50) of cutting the cured molded product 10c in a cutting direction (V) substantially perpendicular to the second central axis (C2) to have a predetermined thickness (t), extrusion Unlike the conventional manufacturing method in which the diameter of the sheet base material is limited due to limitations in the molding itself, a large-sized thermally conductive sheet 100 can be manufactured, and mass production is also easy to achieve.

In the method of manufacturing the thermally conductive sheet, in the stacking process (S20), the primary preform (10a) obtained in the comma forming process (S10) is cut to a predetermined length and then stacked in plural pieces in the thickness direction. By doing so, since the laminated molded product S is obtained, there is an advantage that it is easy to obtain a relatively voluminous laminated molded product S so that the large-sized thermally conductive sheet 100 can be manufactured.

In addition, the method of manufacturing the thermally conductive sheet includes, in the press molding process (S30), the laminated molded product (S) being inserted into a mold member 320 of a predetermined shape, and the thickness of the laminated molded product (S) ( By pressing the laminated molding (S) along the H) direction, the laminated molding (S) can be converted into a secondary preform (10b) of a predetermined shape, and the efficiency of the press forming process (S30) is also increased. There is an advantage to being able to do it.

In the method of manufacturing the thermally conductive sheet, the comma member 250 has a unit groove portion 251a extending along the second central axis C2 as shown in FIGS. 2 and 3 and is located at the first center. Since it is provided with a plurality of molding grooves 251 formed by arranging them along the axis C1, the orientation of the anisotropic heat conductive filler 1 present inside the primary preform 10a is improved and at the same time, the relative width W ) has the advantage of securing a wide primary preform (10a).

In addition, in the method of manufacturing the thermal conductive sheet, the cross-sectional shape of the unit groove portion 251a is at least one selected from the group including circular, semicircular, oval, semielliptical, square, rectangular, and triangular shape, so that the forming groove 251 ) has the advantage of improving the orientation of the anisotropic heat conductive filler (1) present inside the primary preform (10a) compared to the case where it is a single groove in the form of a simple square plate.

In the method of manufacturing the thermally conductive sheet, since the width of the unit groove portion 251a is 1 to 10 mm, the average major axis length (average fiber length) of the carbon fibers of the anisotropic thermally conductive filler 1 is 120 ㎛ to 6. Considering the fact that it is mm, there is an advantage that it is suitable for improving the orientation of the anisotropic thermally conductive filler (1).

In addition, the method of manufacturing the thermally conductive sheet is such that the molding groove 251 has a width (W) of 10 to 50 cm along the first central axis (C1) and 2 along the second central axis (C2). Since it has a length (L) of from 20 cm to 20 cm, there is an advantage in that the first preform (10a) with a relatively wide width (W) can be quickly secured in large quantities.

In addition, the method of manufacturing the thermally conductive sheet has the advantage that the polymer 3 includes a silicone resin, so the thermally conductive sheet 100 has excellent molding processability and weather resistance, and has excellent adhesion and followability to electronic components. There is.

In addition, in the method of manufacturing the thermally conductive sheet, the filler 2 includes at least one of aluminum oxide, aluminum nitride, zinc oxide, silicon powder, and metal powder, thereby producing a thermally conductive sheet 100 with excellent thermal conductivity. There are advantages to doing this.

In the manufacturing method of the thermal conductive sheet, since the filler 2 includes spherical aluminum oxide particles with an average particle diameter of 0.1 μm to 45 μm, the thermal conductive sheet 100 with excellent thermal conductivity and fillability can be manufactured. There are advantages to this.

In addition, the method for producing the thermally conductive sheet is such that the content of the filler 2 in the thermally conductive composition is 20 to 40% by volume, so that the thermally conductive sheet 100 with appropriate flexibility and thermal conductivity can be manufactured. There is an advantage.

In the method of producing the thermal conductive sheet, the anisotropic thermal conductive filler (1) has a content of 20 to 50 vol% in the thermal conductive composition, so that it provides sufficient thermal conductivity to the molded body and at the same time provides formability and orientation. There is an advantage in manufacturing this excellent thermally conductive sheet 100.

In addition, the method of manufacturing the thermally conductive sheet is that the anisotropic thermally conductive filler (1) is selected from the group including boron nitride (BN) powder, graphite, carbon fiber, and carbon nanotube (Carbon nanotube, CNT). Since it includes at least one, there is an advantage in manufacturing a thermally conductive sheet 100 with excellent thermal conductivity and durability.

Although the present invention has been described above, the technical scope of the present invention is not limited to the contents described in the above-described embodiments, and equivalent configurations modified or changed by those skilled in the art may be interpreted as the technical scope of the present invention. It is clear that it does not go beyond the scope of thought.

＊ Explanation of symbols for main parts of the drawing ＊
1: Anisotropic thermally conductive filler
2: Filler
3: polymer
10c: Cured molding
10a: Primary preform
10b: Secondary preform
100: thermally conductive sheet
200: Comma coating machine
210: coating roller
220: Film member
230: Absence of dam
240: Absence of lifting and lowering
241: slope
250: Absence of comma
251a: Unit groove part
251: Molded groove
260: transfer device
261: motor
262: Number member
263: Arm member
300: Press molding machine
310: Pressure member
320: Mold member
400: ultrasonic cutter
P: Pressure direction
S: Laminated molding
V: Vibration direction

Claims (14)

By introducing a thermally conductive composition containing a polymer, an anisotropic thermally conductive filler, and a filler into a comma coater including a comma member and a coating roller rotating along a first central axis, the anisotropic thermally conductive filler intersects the first central axis. A comma forming process of obtaining a sheet-shaped primary preform oriented along a second central axis, extending along the second central axis, and having a predetermined thickness;
A stacking process of obtaining a laminated molded product by stacking a plurality of the primary preforms in the thickness direction;
A press molding process of obtaining a secondary preform in which the anisotropic heat conductive filler of the laminated molded product is oriented in a direction intersecting the thickness direction by pressing the laminated molded product along the thickness direction of the laminated molded product using a press molding machine;
A curing process of obtaining a cured molded product by curing the secondary preform;
A cutting process of cutting the cured molded product in a cutting direction intersecting the second central axis to have a predetermined thickness,
The absence of the comma is,
A method of manufacturing a thermally conductive sheet, characterized in that it has a forming groove formed by arranging a plurality of unit grooves extending along the second central axis along the first central axis. According to clause 1,
In the lamination process,
A method of manufacturing a thermally conductive sheet, characterized in that the laminated molded product is obtained by cutting the primary preform obtained in the comma forming process to a predetermined length and then stacking a plurality of pieces in the thickness direction. According to clause 1,
In the lamination process,
A method of manufacturing a thermally conductive sheet, characterized in that the laminated molded product is obtained by rolling and stacking the primary preform obtained in the comma forming process a plurality of times into a roll shape with the first central axis as the center of rotation. According to clause 1,
In the press molding process,
A method of manufacturing a thermally conductive sheet, characterized in that the laminated molded product is inserted into a mold member of a predetermined shape and the laminated molded product is pressed along the thickness direction of the laminated molded product. delete According to clause 1,
A method of manufacturing a thermally conductive sheet, characterized in that the cross-sectional shape of the unit groove portion is at least one selected from the group including circular, semi-circular, oval, semi-elliptical, square, rectangular, and triangular. According to clause 1,
A method of manufacturing a thermally conductive sheet, characterized in that the width of the unit groove is 1 to 10 mm. According to clause 1,
The molded groove is,
A method of manufacturing a thermally conductive sheet, characterized in that it has a width of 10 to 50 cm along the first central axis and a length of 2 to 20 cm along the second central axis. According to clause 1,
A method of manufacturing a thermally conductive sheet, wherein the polymer includes a silicone resin. According to clause 1,
The filler is a method of manufacturing a thermally conductive sheet, characterized in that it includes at least one of aluminum oxide, aluminum nitride, zinc oxide, silicon powder, and metal powder. According to clause 1,
A method for producing a thermally conductive sheet, wherein the filler includes spherical aluminum oxide particles with an average particle diameter of 0.1 μm to 45 μm. According to clause 1,
A method of producing a thermally conductive sheet, characterized in that the content of the filler in the thermally conductive composition is 20% to 40% by volume. According to clause 1,
A method for producing a thermally conductive sheet, wherein the anisotropic thermally conductive filler is contained in the thermally conductive composition in an amount of 20 to 50 vol%. According to clause 1,
The anisotropic thermally conductive filler is a thermally conductive sheet comprising at least one selected from the group consisting of boron nitride (BN) powder, graphite, carbon fiber, and carbon nanotube (CNT). Manufacturing method.

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