CN110734562B

CN110734562B - Graphene fiber oriented heat conducting sheet and preparation method thereof

Info

Publication number: CN110734562B
Application number: CN201911157840.8A
Authority: CN
Inventors: 郭志军; 杨兰贺; 陈瑶
Original assignee: Jiangsu Honglingda Technology Co ltd; Shenzhen Hanhua Thermal Management Technology Co Ltd
Current assignee: Jiangsu Honglingda Technology Co ltd; Shenzhen Hanhua Thermal Management Technology Co Ltd
Priority date: 2019-11-22
Filing date: 2019-11-22
Publication date: 2020-07-03
Anticipated expiration: 2039-11-22
Also published as: CN110734562A

Abstract

The invention provides a graphene fiber oriented heat conducting sheet and a preparation method thereof, wherein the preparation method comprises the following steps: step 1: uniformly mixing matrix resin, graphene fibers and heat-conducting powder by using a stirring device to obtain a mixture; step 2: pouring the mixture into an annular groove of a forming device, and opening the forming device to enable the annular groove to rotate around the center of the annular groove; orienting the graphene fibers in the mixture in the flow direction; simultaneously heating the mixture to obtain an annular solid; and step 3: placing the annular solid in an oven for heating and curing; and 4, step 4: and slicing the heated and cured annular solid object along the radius direction of the ring by using a slicing device to obtain the heat conducting sheet with the graphene fibers oriented and arranged in the thickness direction. The preparation method of the graphene fiber oriented heat conducting fin provided by the invention is used for preparing the graphene fiber oriented heat conducting fin in the thickness direction, so that the prepared heat conducting fin has better heat conducting property.

Description

Graphene fiber oriented heat conducting sheet and preparation method thereof

Technical Field

The invention relates to the technical field of heat conducting fins, in particular to a heat conducting fin with graphene fibers arranged in an oriented mode and a preparation method thereof.

Background

At present, the common high-thermal-conductivity gasket generally has the problems of high inorganic powder filling amount and poor physical properties of the gasket, such as flexibility, toughness, elasticity and the like due to high filling. The heat conductivity coefficient of traditional inorganic powder such as alumina, aluminum nitride, boron nitride and the like is below 300W, the heat conducting sheet made of inorganic powder filling is generally below 10W, and the heat conducting performance of traditional heat conducting powder limits the improvement of the heat conducting performance of the high heat conducting gasket.

For the fiber and sheet heat conduction materials, the heat conduction performance of the fiber and sheet heat conduction materials is anisotropic in the axial direction and the radial direction of the fiber.

Disclosure of Invention

The invention provides a preparation method of a graphene fiber oriented heat conducting fin, which is used for preparing the graphene fiber oriented heat conducting fin in the thickness direction, so that the prepared heat conducting fin has better heat conducting property.

The embodiment of the invention provides a preparation method of a graphene fiber orientation arranged heat conducting sheet, which comprises the following steps:

step 1: uniformly mixing matrix resin, graphene fibers and heat-conducting powder by using a stirring device to obtain a mixture;

step 2: pouring the mixture into an annular groove of a forming device, and opening the forming device to enable the annular groove to rotate around the center of the annular groove; orienting the graphene fibers in the mixture in the flow direction; simultaneously heating the mixture to obtain an annular solid;

and step 3: placing the annular solid in an oven for heating and curing;

and 4, step 4: and slicing the heated and cured annular solid object along the radius direction of the ring by using a slicing device to obtain the heat conducting sheet with the graphene fibers oriented and arranged in the thickness direction.

Preferably, the matrix resin comprises one or a combination of two of an addition reaction type liquid silicone resin and a peroxide cured silicone resin.

Preferably, the heat-conducting powder comprises one or a combination of metal powder and inorganic powder.

Preferably, the metal powder includes: one or more of aluminum powder, copper powder, silver powder and gold powder;

the inorganic powder includes: one or more of aluminum oxide, aluminum nitride, boron nitride and silicon carbide.

Preferably, the curing temperature of the annular solid object when the annular solid object is placed in an oven and heated is 100-150 ℃.

Preferably, the graphene fibers account for 10-30% of the mixture by mass, the matrix resin accounts for 5-20% of the mixture by mass, and the thermal conductive powder accounts for 50-75% of the mixture by mass.

Preferably, the molding device includes:

a support;

the rotary platform is provided with an annular groove; a rotating shaft is fixedly arranged in the middle of the bottom end of the rotating platform and is connected with the support through a bearing;

the motor is in transmission connection with the rotating platform to enable the annular groove to rotate at the center position of the annular groove;

the first heating mechanism is arranged below the rotary platform, and electric heating wires of the first heating mechanism are distributed at corresponding positions of the annular groove;

the second heating mechanism is arranged above the rotating platform, and electric heating wires of the second heating mechanism are distributed at corresponding positions of the annular groove;

and one end of the vertical telescopic mechanism is fixedly connected with the support, the other end of the vertical telescopic mechanism is connected with a U-shaped connecting piece, and the other end of the U-shaped connecting piece is fixedly connected with the second heating mechanism.

Preferably, the molding device further comprises a temperature sensor arranged in the annular groove and used for detecting the temperature in the annular groove;

the temperature detection circuit is connected with the temperature sensor;

the temperature detection circuit includes:

a first input 16, a second input 17 and a signal output 18; the first input end is grounded, and the second input end is connected to the non-inverting input end of the operational amplifier U after being connected to the resistor R1;

one end of the capacitor C1 is grounded, and the other end of the capacitor C1 is connected to the non-inverting input end of the operational amplifier U;

one end of the resistor R2 is grounded, and the other end of the resistor R5 is connected to the reverse input end of the operational amplifier U; the capacitor C2 is connected with the resistor R2 in parallel;

one end of the resistor R3 is connected with a power supply VCC, and the other end is connected between the resistor R2 and the resistor R5;

one end of the resistor R4 is connected with a power VCC, and the other end is connected with the non-inverting input end of the operational amplifier U;

one end of the resistor R6 is connected with the output end of the amplifier U, and the other end is connected with the non-inverting input end of the amplifier U;

one end of the resistor R7 is connected to the output end of the operational amplifier U;

one end of the resistor R8 is connected with a power VCC, and the other end is connected with the other end of the resistor R7, which is far away from the end connected with the output end of the operational amplifier U;

the other end of the resistor R7, which is far away from the end connected with the output end of the operational amplifier U, is taken as a signal output end 18 of the detection circuit;

one end of the first temperature sensor 10, the second temperature sensor 11, the third temperature sensor 12 or the fourth temperature sensor 13 is connected to the first input end 16, and the other end is connected to the second input end 17.

Preferably, the slicing apparatus comprises:

the device comprises a shell, a first fixing piece and a second fixing piece, wherein one end of the shell is provided with a circular groove;

the rotating shaft is arranged at the center of the circular groove and used for sleeving the annular solid object;

the cutter mechanism is arranged below the rotating shaft and can move up and down in the vertical direction;

the pressing wheel is arranged below the rotating shaft and positioned on one side of the cutter mechanism and used for pressing the annular solid object on the rotating shaft;

the splicing device is arranged on one side of the cutter mechanism, which is far away from the pressing wheel, and is used for splicing the arc-shaped splicing plate to the tail end of the annular solid object in the slicing process of the annular solid object;

the splicing apparatus includes:

a main body having a cavity therein; the main body is fixedly connected with the shell and arranged on one side of the cutter mechanism far away from the pinch roller; the cavity is provided with an opening at one side of the main body close to the rotating shaft; the cavity is used for placing an arc-shaped splice plate;

the push plate is arranged in the cavity, is positioned below the arc-shaped connecting plate and is used for pushing the arc-shaped connecting plate to the position of the tail end of the annular solid object to be connected with the annular solid object;

the continuous cylinder is arranged in the cavity and positioned below the push plate, one end of the continuous cylinder is fixedly connected with the main body, and the other end of the continuous cylinder is fixedly connected with the push plate;

and the infrared detector is arranged on one side surface of the main body close to the cutter mechanism and used for detecting that the tail end of the annular solid object reaches the corresponding position of the main body.

The invention also provides a graphene fiber oriented heat conducting sheet prepared by any one of the preparation methods.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic view of a method for preparing a thermally conductive sheet with oriented graphene fibers according to an embodiment of the present invention;

FIG. 2 is a schematic view of a molding apparatus according to an embodiment of the present invention;

FIG. 3 is a schematic view of a rotary platen of a molding apparatus according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a temperature detection circuit according to an embodiment of the present invention;

FIG. 5 is a schematic view of a slicing apparatus according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a splicing apparatus of a slicing apparatus according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a splicing apparatus of another slicing apparatus according to an embodiment of the present invention;

FIG. 8 is an enlarged view taken at A of FIG. 7;

FIG. 9 is a schematic view of a stirring device according to an embodiment of the present invention.

In the figure:

1. a housing; 2. a circular groove; 3. an annular solid; 4. a rotating shaft; 5. a pinch roller; 6. a cutter mechanism; 7. a connecting device; 16. a first input terminal; 17. a second input terminal; 18. a signal output terminal; 21. a support; 22. rotating the platform; 23. an annular groove; 24. a rotating shaft; 25. a motor; 26. a first heating mechanism; 27. a second heating mechanism; 28. a vertical telescopic mechanism; 29. a U-shaped connecting piece; 31. a body; 32. a stirring chamber; 33. an inlet; 34. a stirring motor; 35. an output shaft; 36. a linker; 37. a first stirring blade; 38. a second stirring shaft; 39. a first drive gear; 40. a second transmission gear; 41. a first stirring shaft; 42. a second stirring blade; 71. an infrared detector; 72. an arc-shaped connecting plate; 73. connecting the cylinder; 74. pushing the plate; 75. a main body; 76. a storage chamber; 77. a push chamber; 761. a spring; 762. a storage plate; 771. a pushing motor; 772. a turntable; 773. a transmission rod; 774. a first connecting rod; 775. a second connecting rod; 776. a pushing body; 777. a pulley; 778. a T-shaped linker; 779. t-shaped slide way.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

The embodiment of the invention provides a graphene fiber oriented heat conducting sheet and a preparation method thereof, and as shown in fig. 1, the graphene fiber oriented heat conducting sheet comprises the following steps:

step 2: pouring the mixture into the annular groove 23 of the forming device, and opening the forming device to enable the annular groove 23 to rotate around the center of the annular groove; orienting the graphene fibers in the mixture in the flow direction; simultaneously heating the mixture to obtain an annular solid 3;

and step 3: placing the annular solid 3 in an oven for heating and curing;

and 4, step 4: and slicing the heated and cured annular solid object 3 along the radius direction of the circular ring by using a slicing device to obtain the heat conducting sheet with the graphene fibers oriented and arranged in the thickness direction.

The working principle and the beneficial effects of the technical scheme are as follows:

the heat conducting sheet with the oriented arrangement of the graphene fibers mainly comprises: preparing a mixture, forming, curing and slicing.

The preparation of the mixture is specifically as follows: uniformly mixing matrix resin, graphene fibers and heat-conducting powder by using a stirring device to obtain a mixture; when mixing, a curing agent, a diluent, a flame retardant, a catalyst, a tackifier, and the like may be added in an appropriate amount.

The molding process specifically comprises the following steps: pouring the mixture into the annular groove 23 of the forming device, and opening the forming device to enable the annular groove 23 to rotate at the center; orienting the graphene fibers in the mixture in the flow direction; simultaneously heating the mixture to obtain an annular solid 3;

the curing process specifically comprises the following steps: placing the annular solid 3 in an oven for heating and curing;

the slicing procedure specifically comprises the following steps: and slicing the heated and cured annular solid object 3 along the radius direction of the circular ring by using a slicing device to obtain the heat conducting sheet with the graphene fibers oriented and arranged in the thickness direction.

By the preparation method of the heat conducting fin with the oriented arrangement of the graphene fibers, the heat conducting fin with the oriented arrangement of the graphene fibers in the thickness direction is prepared, so that the prepared heat conducting fin has better heat conducting performance.

In one embodiment, the matrix resin comprises one or a combination of an addition reaction type liquid silicone resin, a peroxide cured silicone resin.

the matrix resin is used as an important carrier for mixing, is not particularly limited, and can be selected from thermosetting elastomers and thermoplastics according to performance requirements. The thermosetting elastomer can be selected from thermosetting polyurethane elastomer, thermosetting acrylate elastomer, thermosetting silicone resin, thermosetting hydroxyl-terminated polybutadiene, thermosetting isoprene rubber, thermosetting butadiene rubber, thermosetting silicone rubber and the like. The thermoplastic may be selected from polyethylene, polypropylene, polyethylene-vinyl acetate copolymer, polyvinyl alcohol, polyethylene terephthalate, polyvinyl alcohol, polyacrylic acid, polycarbonate, polyamide, and the like. The matrix resin, preferably a thermoset elastomer, is preferred depending on performance requirements. The thermosetting elastomer is preferably thermosetting silicone rubber. The thermosetting silicone rubber may be selected from addition reaction type liquid silicone resins and peroxide-vulcanized silicone resins. One of them may be selected or both may be combined together according to performance requirements.

In one embodiment, the thermally conductive powder includes one or a combination of a metal powder and an inorganic powder.

In one embodiment, the metal powder includes: one or more of aluminum powder, copper powder, silver powder and gold powder;

the metal powder can be selected from aluminum powder, copper powder, silver powder, gold powder, etc. Aluminum powder, copper powder and silver powder are preferred according to the performance requirements. More preferably aluminum powder or silver powder. The particle diameter of the heat-conducting metal powder can be selected from 0.3um-20um, and the spherical aluminum powder with the average particle diameter of 0.6um-5um is preferred. The inorganic powder can be selected from aluminum oxide, aluminum nitride, boron nitride, silicon carbide, etc. Spherical alumina and aluminum nitride having an average particle diameter of 0.6 to 5um are preferable.

In one embodiment, the curing temperature of the annular solid 3 when placed in an oven for heating and curing is 100-150 ℃.

In one embodiment, the graphene fibers account for 10-30% of the mixture by mass, the matrix resin accounts for 5-20% of the mixture by mass, and the thermal conductive powder accounts for 50-75% of the mixture by mass.

In one embodiment, as shown in fig. 2 and 3, the molding apparatus includes:

a bracket 21;

a rotary platform 22 on which an annular groove 23 is provided; a rotating shaft 24 is fixedly arranged in the middle of the bottom end of the rotating platform 22, and the rotating shaft 24 is connected with the bracket 21 through a bearing;

a motor 25, which is connected with the rotary platform 22 in a transmission way and enables the annular groove 23 to rotate at the central position thereof;

the first heating mechanism 26 is arranged below the rotating platform 22, and electric heating wires of the first heating mechanism 26 are distributed at corresponding positions of the annular groove 23;

the second heating mechanism 27 is arranged above the rotating platform 22, and electric heating wires of the second heating mechanism 27 are distributed at corresponding positions of the annular groove 23;

and one end of the vertical telescopic mechanism 28 is fixedly connected with the bracket 21, the other end of the vertical telescopic mechanism 28 is connected with a U-shaped connecting piece 29, and the other end of the U-shaped connecting piece 29 is fixedly connected with the second heating mechanism 27.

the mixture is poured into the annular groove 23 and the second heating means 27 is lowered by the vertical telescopic means 28 to a position above the annular groove 23. The motor 25 is then turned on and the motor 25 drives the rotary platform 22. The graphene fibers in the mixture can be oriented along the rotation direction in the rotation process; according to specific requirements, the first heating mechanism 26 and the second heating mechanism 27 are started to heat the mixture; finally, the annular solid 3 is manufactured. The diluent and the like will evaporate out during heating, and in some cases a suction hood may be provided to cover the second heating means 27 and the annular groove 23 during heating, in particular: an arc-shaped cover body is sleeved at the fixed connection position of the vertical telescopic mechanism 28 and the second heating mechanism 27, an exhaust port is arranged at the upper end of the cover body, and the exhaust port is connected to air suction equipment. The vertical extension mechanism 28 thus covers the second heating means 27 together with the annular groove 23 while lowering the second heating means 27. The vertical retracting mechanism 28 may be a retracting cylinder.

In one embodiment, the molding apparatus further includes a temperature sensor disposed in the annular groove 23 for detecting a temperature in the annular groove 23;

the temperature detection circuit is connected with the temperature sensor;

as shown in fig. 4, the temperature detection circuit includes:

one end of the temperature sensor is connected with the first input end 16, and the other end is connected with the second input end 17.

the temperature sensor is KTY type. When the first input end 16 and the second input end 17 of the detection circuit are connected, when the temperature is lower than the threshold temperature, the output of the operational amplifier U is at a high level, and when the temperature of the setting position of the temperature sensor is higher than the threshold temperature, the output of the comparator is reversed at the moment, and the output of the operational amplifier U is at a low level. The output level of the detection circuit can directly control the opening of the first heating device and the second heating device, so that the heating temperature can be controlled.

In one embodiment, as shown in fig. 5 and 6, the slicing apparatus includes:

the device comprises a shell 1, wherein a circular groove 2 is formed in one end of the shell 1;

the rotating shaft 4 is arranged at the center of the circular groove 2 and is used for sleeving the annular solid object 3;

the cutter mechanism 6 is arranged below the rotating shaft 4, and the cutter mechanism 6 can move up and down in the vertical direction;

the pressing wheel 5 is arranged below the rotating shaft 4 and on one side of the cutter mechanism 6 and is used for pressing the annular solid object 3 on the rotating shaft 4;

the connecting device 7 is arranged on one side of the cutter mechanism 6, which is far away from the pressing wheel 5, and is used for connecting the arc-shaped connecting plate 72 to the tail end of the annular solid object 3 in the slicing process of the annular solid object 3;

the splicing device 7 includes:

a main body 75 having a cavity therein; the main body 75 is fixedly connected with the shell 1 and is arranged on one side of the cutter mechanism 6 far away from the pinch roller 5; the cavity is provided with an opening at one side of the main body 75 close to the rotating shaft 4; the cavity is used for placing the arc-shaped splice plate 72;

the push plate 74 is arranged in the cavity and positioned below the arc-shaped connecting plate 72 and used for pushing the arc-shaped connecting plate 72 to the position of the tail end of the annular solid object 3 to be connected with the annular solid object 3;

a connecting cylinder 73 arranged in the cavity below the push plate 74, one end of which is fixedly connected with the main body 75 and the other end of which is fixedly connected with the push plate 74;

and the infrared detector 71 is arranged on one side surface of the main body 75 close to the cutter mechanism 6 and is used for detecting that the tail end of the annular solid object 3 reaches the corresponding position of the main body 75.

the worker sleeves the annular solid object 3 on the rotating shaft 4; and the ring-shaped solid 3 is pressed against the rotary shaft 4 by the pressing wheel 5. The slicing device is started, the cutter mechanism 6 moves upwards to cut the annular solid object 3, when the cutter mechanism 6 moves downwards, the rotating shaft 4 rotates for a preset angle, then the cutter mechanism 6 moves upwards again to cut the annular solid object 3, and therefore the heat conducting fins with the required thickness and arranged in the graphene fiber orientation mode are cut. However, when the annular solid 3 is sliced by the cutter mechanism 6, the last tailing is always left and cannot be sliced. Therefore, the arc-shaped splicing plate 72 is connected to the tail end of the annular solid object 3 by the splicing device 7 in the slicing process, so that the tailing residue of the annular solid object 3 can be reduced. When the infrared detector 71 detects that the end of the annular solid object 3 reaches the corresponding position of the connection device 7 (after a predetermined time elapses from the detection of the end by the infrared detector 71, the corresponding position is considered to be reached, and the predetermined time is mainly determined according to the rotation speed of the rotation shaft 4 and the width of the main body 75), the connection device 7 operates to push the arc-shaped connection plate 72 to be connected with the end of the annular solid object 3. The specific connection action is as follows: the connecting cylinder 73 acts to push the push plate 74, and the push plate 74 pushes the arc-shaped connecting plate 72; one side of the arc-shaped connecting plate 72 is provided with an adhesive which connects the arc-shaped connecting plate 72 with the annular solid 3. The switching cylinder 73 may be a vertical telescopic cylinder. In order to make the heat conduction efficiency of the cut heat conducting strips better, the cutter mechanism 6 adopts an ultrasonic cutter.

In one embodiment, as shown in fig. 7 and 8, the splicing device further comprises:

a storage chamber 76 provided in the main body 75 beside the cavity; the bottom of the storage chamber 76 is provided with a spring 761; one end of the spring 761 is fixedly connected with the bottom of the storage cavity 76, and the other end is fixedly connected with a storage plate 762; a plurality of arc-shaped splice plates 72 are stored on the storage plate 762;

a push chamber 77 disposed within the body 75, adjacent to the cavity; the pushing cavity 77 and the storage cavity 76 are communicated with the cavity; a pushing motor 771 is arranged at the bottom of the pushing cavity 77, a rotating disc 772 is arranged at the output end of the pushing motor 771, and a transmission rod 773 is vertically arranged on the upper end face of the rotating disc 772;

one end of the first connecting rod 774 is sleeved on the transmission rod 773, and the other end is hinged with one end of the second connecting rod 775; the other end of the second connecting rod 775 is hinged with the left end face of the pushing body 776; a T-shaped connector 778 is fixedly arranged on the upper end face of the pushing body 776, and a T-shaped slideway 779 is arranged above the storage cavity 76 of the main body 75; the T-shaped connecting body 778 is arranged in the T-shaped slideway 779; a pulley 777 is provided on the lower end surface of the pushing body 776.

after the push plate 74 connects the arc-shaped connecting plate 72 on the push plate with the annular solid object 3, the connecting cylinder 73 descends to the original position; then the pushing motor 771 works to drive the turntable 772 to rotate, and through the transmission connection among the transmission rod 773, the first connecting rod 774, the second connecting rod 775 and the pushing body 776, the pushing body 776 moves in the direction of the T-shaped slide track 779, and the arc-shaped connecting plate 72 stored on the uppermost surface of the storage cavity 76 is pushed to the pushing plate 74. Then the pushing body 776 is driven by the pushing motor 771 to retract backwards to the left end of the T-shaped slideway 779; the spring 761 sends the next arc-shaped splice plate 72 to the right side of the pushing body 776; waiting for the next push. By storing the arc-shaped connecting plates 72 in the storage cavity 76, the arc-shaped connecting plates 72 are added after the cutter device cuts the annular solid objects 3, so that the working efficiency is improved. The pulley 777 is provided on the lower end surface of the pushing body 776 to reduce the friction with the arc-shaped connecting body 72 below when the pushing body 776 retracts.

In one embodiment, as shown in fig. 9, the stirring device includes:

the body 31 is internally provided with a stirring cavity 32, an inlet 33 is arranged at the side end of the body 31 close to the top end, and an outlet is arranged at the bottom end of the body 31;

a stirring motor 34 connected to the upper end of the body 31 through a frame;

the output shaft 35 is vertically arranged at the position of the central shaft of the stirring cavity, and one end of the output shaft is connected with the output end of the stirring motor 34;

the middle part of the connecting body 36 is fixedly connected with the middle part of the output shaft 35;

one end of the first stirring shaft 41 is fixedly connected with one end of the connecting body 36, and the first stirring shaft 41 and the connecting body 36 are L-shaped; a plurality of first stirring blades 37 are sequentially and fixedly arranged on the first stirring shaft 41, and the middle parts of the first stirring blades 37 are fixedly connected with the first stirring shaft 41;

one end of the second stirring shaft 38 is rotatably connected with one end of the connecting body 36, which is far away from the first stirring shaft 41, and the second stirring shaft 38 and the connecting body 36 are L-shaped; a plurality of second stirring blades 42 are arranged on two sides of the second stirring shaft 38 in a staggered manner;

the first transmission gear 39 is fixedly arranged at one end of the output shaft 35 far away from the stirring motor 34;

the second transmission gear 40 is fixedly arranged at one end of the second stirring shaft 38 close to the connecting body 36; the first transmission gear 39 is in transmission connection with the second transmission gear 40 through a chain.

the first transmission gear 39 drives the second transmission gear 40 to rotate through a chain; the second transmission gear 40 is arranged on the second stirring shaft 38, so that the second stirring shaft 38 can be driven to rotate; when the stirring device is manufactured according to the stirring requirement, the first transmission gear 39 and the second transmission gear 40 are selected based on the transmission ratio of the first transmission gear 39 and the second transmission gear 40, so that the rotating speed of the second stirring shaft 38 meets the use requirement.

The stirring motor 34 drives the connecting body 36 to rotate by taking the connecting position of the output shaft 35 and the connecting body 36 as a circle center, and the first stirring shaft 41 and the second stirring shaft 38 stir the materials; the stirring direction of the first stirring shaft 41 is the circumferential direction, so that the materials are stirred in a large range; the second stirring shaft 38 not only stirs the material in a large range in the circumferential direction, but also rotates under the driving of the second transmission gear 40 to stir the material in a small range precisely. Better mixing of materials is realized through large-range coarse stirring and small-range precise stirring; achieving better stirring effect.

The invention also provides a heat conducting sheet with the graphene fibers arranged in an oriented mode, and the heat conducting sheet is prepared by any one of the preparation methods.

Specific application examples of the preparation process of the present invention are listed below:

example one

Vinyl silicone oil with the viscosity of 1000mpa.s and the mass ratio of 10 percent, graphene fiber with the average length of 150um and the average diameter of 10um and the mass ratio of 25 percent, aluminum powder with the average particle diameter of 1um and the mass ratio of 65 percent, and necessary other auxiliary agents are added into a stirrer to be stirred and mixed for 1.5 h. The stirrer is provided with a vacuum pumping device, and air in the materials is removed in the stirring process. After the mixture is prepared, it is added to the oriented annular trough. And opening the forming device. The rotating speed is 80r/min, heating is started after the rotation is carried out for 15min, and the temperature is set to be 55 ℃. And controlling the proper crosslinking degree of the material to fix the arrangement of the graphene fibers in the material so as to obtain an annular solid. And (5) putting the annular solid object into a 140-degree oven for 1h, and curing.

The obtained annular solid matter is cut into heat-conducting gaskets of 0.5mm, 1mm and 2mm by a slicing knife.

Example two

Vinyl silicone oil with the viscosity of 1000mpa.s and the mass ratio of 10%, graphene fiber with the average length of 150um and the average diameter of 10um and the mass ratio of 25%, aluminum powder with the average particle size of 1um and the mass ratio of 15%, spherical alumina with the average particle size of 0.8um and the mass ratio of 15%, spherical alumina with the average particle size of 2um and the mass ratio of 35%, and necessary other auxiliary agents are added into a stirrer to be stirred and mixed for 1.5h, so as to prepare a mixture. The subsequent operation is as in embodiment one.

EXAMPLE III

Vinyl silicone oil with the viscosity of 500mpa.s and the mass ratio of 10%, graphene fiber with the average length of 150um and the average diameter of 10um and the mass ratio of 25%, spherical alumina with the average particle size of 0.8um and the mass ratio of 10%, spherical alumina with the average particle size of 2um and the mass ratio of 55%, and necessary other auxiliary agents are added into a stirrer to be stirred and mixed for 1.5h, and a mixture is prepared. The subsequent operation is as in embodiment one.

Example four

The preparation method comprises the following steps of adding 10 mass percent of 500mpa.s viscosity vinyl silicone oil, 15 mass percent of graphene fiber with the average length of 150um and the average diameter of 10um, 10 mass percent of graphite flake powder with the average size of 100um, 25um width and 15um thickness, 10 mass percent of spherical alumina with the average particle size of 0.8um and the average particle size of 55 mass percent, and necessary other additives into a stirrer, stirring and mixing for 1.5 hours to prepare a mixture. The subsequent operation is as in embodiment one.

EXAMPLE five

Adding 8 mass percent of vinyl silicone oil with the viscosity of 500mpa.s, 2 mass percent of silicone oil chain extender, 35 mass percent of graphene fiber with the average diameter of 10um and the length of 150um, 10 mass percent of spherical alumina with the average particle size of 0.8um, 45 mass percent of spherical alumina with the average particle size of 2um, necessary other auxiliary agents and the like into a stirrer, and stirring and mixing for 1.5 hours to prepare a mixture. The subsequent operation is as in embodiment one.

EXAMPLE six

Adding 8 mass percent of vinyl silicone oil with the viscosity of 500mpa.s, 2 mass percent of silicone oil chain extender, 35 mass percent of graphene fiber with the average diameter of 10um and the length of 150um, 10 mass percent of aluminum nitride with the average particle size of 0.8um, 45 mass percent of spherical alumina with the average particle size of 2um, necessary other auxiliary agents and the like into a stirrer, and stirring and mixing for 1.5 hours to prepare a mixture. The subsequent operation is as in embodiment one.

EXAMPLE seven

Adding 8 mass percent of vinyl silicone oil with the viscosity of 500mpa.s, 2 mass percent of silicone oil chain extender, 35 mass percent of graphene fiber with the average diameter of 10um and the length of 150um, 10 mass percent of aluminum nitride with the average particle size of 0.8um, 10 mass percent of aluminum powder with the average particle size of 1um, 35 mass percent of spherical alumina with the average particle size of 2um, necessary other auxiliary agents and the like into a stirrer, and stirring and mixing for 1.5 hours to prepare a mixture. The subsequent operation is as in embodiment one.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A preparation method of a heat conducting sheet with oriented graphene fibers is characterized by comprising the following steps:

and step 3: placing the annular solid in an oven for heating and curing;

and 4, step 4: slicing the heated and cured annular solid object along the radius direction of the circular ring by using a slicing device to obtain heat conducting sheets in which the graphene fibers are oriented and arranged in the thickness direction;

the graphene fiber accounts for 10% -30% of the mixture by mass, the matrix resin accounts for 5% -20% of the mixture by mass, and the heat-conducting powder accounts for 50% -75% of the mixture by mass;

the slicing apparatus includes:

the splicing apparatus includes:

2. The method of claim 1, wherein the base resin comprises one or a combination of an addition reaction type liquid silicone resin and a peroxide cured silicone resin.

3. The method according to claim 1, wherein the thermally conductive powder comprises one or a combination of a metal powder and an inorganic powder.

4. The method according to claim 3, wherein the metal powder comprises: one or more of aluminum powder, copper powder, silver powder and gold powder;

5. The method as claimed in claim 1, wherein the curing temperature of the annular solid material is 100-150 ℃ when the annular solid material is placed in an oven for heating and curing.

6. The method of manufacturing according to claim 1, wherein the molding device comprises:

a support;

7. The manufacturing method according to claim 6, wherein the molding device further includes a temperature sensor provided in the annular groove for detecting a temperature in the annular groove;

the temperature detection circuit is connected with the temperature sensor;

the temperature detection circuit includes:

8. A heat conductive sheet with oriented graphene fibers, which is prepared by the preparation method of any one of claims 1 to 7.