CN111548161A

CN111548161A - Method for manufacturing super-thick artificial graphite film

Info

Publication number: CN111548161A
Application number: CN202010338287.4A
Authority: CN
Inventors: 朱先磊; 葛志远; 王星
Original assignee: Anhui Hengtan New Material Technology Co ltd
Current assignee: Anhui Hengtan New Material Technology Co ltd
Priority date: 2020-04-26
Filing date: 2020-04-26
Publication date: 2020-08-18

Abstract

The invention discloses a method for manufacturing an ultra-thick artificial graphite film, which comprises the following steps: the method comprises the following steps: preparing a PI film coiled material; step two: loading the roll; step three: vacuum carbonization; firstly, feeding the boat into a carbonization furnace and vacuumizing; then, heating in sections; finally, naturally cooling to room temperature; step four: graphitizing at high temperature; firstly, a boat is conveyed into a graphite furnace, and the interior of the graphite furnace is vacuumized; then, filling inert protective gas into the graphite furnace; then, the interior of the graphite furnace is heated to 1800-2000 ℃ from normal temperature and is kept warm for 1-1.5 h; then, raising the temperature inside the graphite furnace from 1800-2000 ℃ to 2750-2850 ℃ and preserving the heat for 30-50 min; finally, naturally cooling to room temperature; step five: and (4) rolling. The artificial graphite film has the advantages of improving the single-layer thickness, the bending resistance and the heat conduction performance of the artificial graphite film, improving the quality of the artificial graphite film and the like.

Description

Method for manufacturing super-thick artificial graphite film

Technical Field

The invention relates to the technical field of artificial graphite film processing, in particular to a manufacturing method of an ultra-thick artificial graphite film.

Background

The artificial graphite film is a very thin heat conduction material, also called as a heat conduction graphite film, a heat conduction graphite sheet, a graphite radiating fin and the like, and provides possibility for thinning development of electronic products. The artificial graphite film has good reprocessing performance, can be compounded with other thin film materials such as PET and the like or coated with glue according to the application, has elasticity, can be cut and stamped into any shape, and can be bent for multiple times; the film is suitable for rapid heat conduction for converting a point heat source into a surface heat source, has high heat conduction performance, and is made of a highly oriented graphite polymer film. At present, the artificial graphite film is widely applied to PDP, LCD TV, notewood PC, UMPC, Flat Panel Display, MPU, Projector, Power Supply, LED, MID and mobile phone; a DVD; a digital camera; computers and peripheral equipment; a sensor; a semiconductor production facility; in electronic products such as optical fiber communication equipment. The preparation of the artificial graphite film comprises the steps of PI film winding, carbonization, graphitization, calendering and the like.

The prior artificial graphite film manufacturing method has defects and insufficiencies in a plurality of steps, so that the thickness of the prepared artificial graphite film can not meet the requirement, and the quality of the artificial graphite film also has defects, firstly, when the PI film is wound, the gaps between the layers of the PI film coiled material are not strictly controlled, when the gaps between the layers of the PI film coiled material are too small, the layers can be attached together, so that the PI film coiled material is heated unevenly when being fired, when the gaps between the layers of the PI film coiled material are too large, the productivity of the artificial graphite film can be seriously reduced, in addition, the sectional heating total heating time in the carbonization and graphitization processes in the prior artificial graphite film manufacturing method is shorter, and the sectional heating maximum temperature is lower, wherein the heating maximum temperature in the carbonization step of the prior artificial graphite film manufacturing method is basically controlled below 1200 ℃, and the whole heating time is basically controlled within 5 hours, therefore, in the carbonization process, the PI film cannot be fully burnt, so that the surface of the finally prepared artificial graphite bulk film has salient points, bright points and arch edges, and the rolling processing of the rear end is not facilitated; in the graphitization step of the existing artificial graphite film manufacturing method, the highest temperature of sectional heating is basically controlled to be 2600-2700 ℃, and the whole heating time is basically 10-12 hours, so that the bending resistance and the heat conductivity of the manufactured artificial graphite film are insufficient, the heat dissipation effect of the artificial graphite film is reduced, the subsequent die cutting processing is inconvenient, and the thickness of the artificial graphite film manufactured by the existing artificial graphite film manufacturing method is generally not more than 60 micrometers based on the defects.

Aiming at the technical problems, the invention discloses a manufacturing method of an ultra-thick artificial graphite film, which has the advantages of improving the bending resistance and the heat conduction performance of the artificial graphite film, reducing the defects of salient points, bright points and arching edges on the surface of the artificial graphite film, facilitating the rolling and die cutting processing of the rear end, increasing the thickness of a single-layer artificial graphite film and the like.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a method for manufacturing an ultra-thick artificial graphite film, and aims to solve the technical problems that the artificial graphite film manufactured by the method for manufacturing the artificial graphite film in the prior art is poor in bending resistance and heat conductivity, serious in surface salient points, bright points and arching defects, inconvenient for subsequent calendering and die cutting processing, incapable of meeting the requirements on single-layer thickness and the like.

The invention is realized by the following technical scheme: the invention discloses a method for manufacturing an ultra-thick artificial graphite film, which comprises the following steps:

the method comprises the following steps: preparing a PI film coiled material, namely winding a PI film on a graphite rod through a rewinding machine to obtain the PI film coiled material;

step two: loading, namely placing the PI film coiled material in a boat;

step three: vacuum carbonization;

firstly, feeding a boat into a carbonization furnace and closing a furnace door;

then, pumping the interior of the carbonization furnace to a vacuum state through a vacuum pump unit;

then, raising the temperature inside the carbonization furnace to 520-550 ℃ from the normal temperature at the speed of 5-7 ℃/min;

then, raising the temperature inside the carbonization furnace from 520-550 ℃ to 910-960 ℃ at a speed of 1.5-2 ℃/min;

then, raising the temperature inside the carbonization furnace from 910-960 ℃ to 1250-1350 ℃ at a speed of 2.5-3.5 ℃/min;

finally, naturally cooling the carbonization furnace to room temperature to obtain a carbonized film;

step four: graphitizing at high temperature;

firstly, taking out the boat from the carbonization furnace and feeding the boat into the graphite furnace, and closing a furnace door of the graphite furnace;

then, the interior of the graphite furnace is pumped to a vacuum state;

then, filling inert protective gas into the graphite furnace;

then, raising the temperature inside the graphite furnace from the normal temperature to 1800-2000 ℃ at the speed of 10-12 ℃/min;

then, keeping the temperature of the graphite furnace at 1800-2000 ℃ for 1-1.5 h;

then, raising the temperature inside the graphite furnace from 1800-2000 ℃ to 2750-2850 ℃ at a speed of 5-6 ℃/min;

then, keeping the temperature of the graphite furnace at 2750-2850 ℃ for 30-50 min;

finally, naturally cooling the graphite furnace to room temperature to obtain a graphitized film;

step five: and (4) calendering, namely pressing the graphitized film on a release film through a calendering process to obtain the ultra-thick artificial graphite film.

Furthermore, in order to enable the PI film coiled material to be heated uniformly in the firing process and improve the productivity of the artificial graphite film as much as possible, in the first step, the gap between every two layers of the PI film coiled material is 160-180 μm.

Furthermore, in order to increase the thickness of the monolayer artificial graphite film, the thickness of the PI film is 80-160 μm.

Further, in order to increase the holding capacity of the PI film coils and thus increase the processing efficiency and the productivity of the artificial graphite film, in the second step, the boat is divided into three layers, and 12 rolls of PI film coils are placed in each layer.

Further, in order to prevent the air pressure in the carbonization furnace from influencing the carbonization process, in the third step, the inside of the carbonization furnace is pumped to a vacuum state through a vacuum pump unit, so that the vacuum degree in the carbonization furnace is controlled below 500pa, and the pressure is maintained for more than 30 min.

Further, in order to minimize the side reaction of the carbonized film during the graphitization process, in step four, the inert shielding gas is helium, argon or xenon.

The invention has the following advantages: in the invention, the gaps between the layers of the PI film coiled material are strictly controlled, the integral heating time in the carbonization and graphitization processes is prolonged, and the highest heating temperature in the carbonization and graphitization processes is increased, so that the PI film is fully carbonized and graphitized, the bending resistance and the heat conductivity of the artificial graphite film are obviously improved, the defects of salient points, bright points and arch edges on the surface of the artificial graphite film are reduced, the rear end is convenient to be calendered and die-cut, and the thickness of a single-layer artificial graphite film is increased.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.

Example 1

Embodiment 1 discloses a method for manufacturing an ultra-thick artificial graphite film, comprising the following steps:

the method comprises the following steps: preparing a PI film coiled material, namely winding a PI film on a graphite rod through a rewinding machine to obtain the PI film coiled material, wherein the gap between each layer of the PI film coiled material is 160-180 mu m, and the thickness of the PI film is 80 mu m;

step two: loading, namely placing the PI film coiled material in a boat, wherein the boat is divided into three layers, and 12 rolls of PI film coiled material are placed in each layer;

step three: vacuum carbonization;

then, the interior of the carbonization furnace is pumped to a vacuum state through a vacuum pump unit, so that the vacuum degree in the carbonization furnace is controlled below 500pa, and the pressure is maintained for more than 30 min;

then, the interior of the carbonization furnace is increased from the normal temperature to 520 ℃ at the speed of 7 ℃/min;

then, the interior of the carbonization furnace is increased from 520 ℃ to 910 ℃ at a speed of 2 ℃/min;

then, the inside of the carbonization furnace was increased from 910 ℃ to 1250 ℃ at a rate of 3.5 ℃/min;

step four: graphitizing at high temperature;

then, the interior of the graphite furnace is pumped to a vacuum state;

then, filling inert protective gas into the graphite furnace, wherein the inert protective gas is helium, argon or xenon;

then, the interior of the graphite furnace is increased from normal temperature to 1800 ℃ at the speed of 12 ℃/min;

then, keeping the temperature of the graphite furnace at 1800 ℃ for 1-1.5 h;

then, the interior of the graphite furnace is increased from 1800 ℃ to 2750 ℃ at the speed of 6 ℃/min;

then, keeping the temperature of the graphite furnace at 2750 ℃ for 30-50 min;

step five: and (2) calendering, namely pressing the graphitized film on a release film through a calendering process to obtain the ultra-thick artificial graphite film, wherein the calendering process is to enable the material to be extruded and sheared for many times through shearing force produced between rollers, so that plasticity is increased, and the material is extended into a thin product on the basis of further plasticization.

Example 2

Embodiment 2 discloses a method for manufacturing an ultra-thick artificial graphite film, comprising the following steps:

the method comprises the following steps: preparing a PI film coiled material, namely winding the PI film on a graphite rod through a rewinding machine to obtain the PI film coiled material, wherein the gap between each layer of the PI film coiled material is 160 mu m, and the thickness of the PI film is 80 mu m;

step three: vacuum carbonization;

then, raising the temperature inside the carbonization furnace to 520 ℃ from the normal temperature at the speed of 6 ℃/min;

then, the inside of the carbonization furnace was increased from 520 ℃ to 910 ℃ at a rate of 1.7 ℃/min;

then, the inside of the carbonization furnace was increased from 910 ℃ to 1250 ℃ at a rate of 3.0 ℃/min;

step four: graphitizing at high temperature;

then, the interior of the graphite furnace is pumped to a vacuum state;

then, the interior of the graphite furnace is increased from normal temperature to 1800 ℃ at the speed of 11 ℃/min;

then, keeping the temperature of the graphite furnace at 1800 ℃ for 1-1.5 h;

then, the interior of the graphite furnace is increased from 1800 ℃ to 2750 ℃ at the speed of 5.5 ℃/min;

Example 3

Embodiment 3 discloses a method for manufacturing an ultra-thick artificial graphite film, comprising the following steps:

the method comprises the following steps: preparing a PI film coiled material, namely winding the PI film on a graphite rod through a rewinding machine to obtain the PI film coiled material, wherein the gap between each layer of the PI film coiled material is 160 mu m, and the thickness of the PI film is 80;

step three: vacuum carbonization;

then, raising the temperature inside the carbonization furnace to 520 ℃ from the normal temperature at the speed of 5 ℃/min;

then, the inside of the carbonization furnace was increased from 520 ℃ to 910 ℃ at a rate of 1.5 ℃/min;

then, the inside of the carbonization furnace was increased from 910 ℃ to 1250 ℃ at a rate of 2.5 ℃/min;

step four: graphitizing at high temperature;

then, the interior of the graphite furnace is pumped to a vacuum state;

then, the interior of the graphite furnace is increased from normal temperature to 1800 ℃ at the speed of 10 ℃/min;

then, keeping the temperature of the graphite furnace at 1800 ℃ for 1-1.5 h;

then, the interior of the graphite furnace is increased from 1800 ℃ to 2750 ℃ at the speed of 5 ℃/min;

Example 4

Embodiment 4 discloses a method for manufacturing an ultra-thick artificial graphite film, comprising the following steps:

step three: vacuum carbonization;

then, the interior of the carbonization furnace is increased from normal temperature to 535 ℃ at the speed of 5 ℃/min;

then, the interior of the carbonization furnace was raised from 535 ℃ to 935 ℃ at a rate of 1.5 ℃/min;

then, the interior of the carbonization furnace is increased from 935 ℃ to 1300 ℃ at a speed of 2.5 ℃/min;

step four: graphitizing at high temperature;

then, the interior of the graphite furnace is pumped to a vacuum state;

then, the interior of the graphite furnace is heated to 1900 ℃ from normal temperature at the speed of 10 ℃/min;

then, keeping the temperature of the graphite furnace at 1900 ℃ for 1-1.5 h;

then, the interior of the graphite furnace was increased from 1900 ℃ to 2800 ℃ at a rate of 5 ℃/min;

then, keeping the temperature of the graphite furnace at 2800 ℃ for 30-50 min;

Example 5

Embodiment 5 discloses a method for manufacturing an ultra-thick artificial graphite film, comprising the following steps:

step three: vacuum carbonization;

then, the interior of the carbonization furnace is heated to 555 ℃ from normal temperature at the speed of 5 ℃/min;

then, the inside of the carbonization furnace was increased from 555 ℃ to 960 ℃ at a rate of 1.5 ℃/min;

then, the inside of the carbonization furnace was increased from 960 ℃ to 1350 ℃ at a rate of 2.5 ℃/min;

step four: graphitizing at high temperature;

then, the interior of the graphite furnace is pumped to a vacuum state;

then, the interior of the graphite furnace is increased from normal temperature to 2000 ℃ at the speed of 10 ℃/min;

then, keeping the temperature of the graphite furnace at 2000 ℃ for 1-1.5 h;

then, the interior of the graphite furnace is increased from 2000 ℃ to 2850 ℃ at the speed of 5 ℃/min;

then, keeping the temperature of the graphite furnace at 2850 ℃ for 30-50 min;

Example 6

Embodiment 6 discloses a method for manufacturing an ultra-thick artificial graphite film, comprising the following steps:

the method comprises the following steps: preparing a PI film coiled material, namely winding the PI film on a graphite rod through a rewinding machine to obtain the PI film coiled material, wherein the gap between each layer of the PI film coiled material is 170 mu m, and the thickness of the PI film is 120;

step three: vacuum carbonization;

then, raising the temperature inside the carbonization furnace from normal temperature to 550 ℃ at the speed of 5 ℃/min;

then, the inside of the carbonization furnace was raised from 550 ℃ to 960 ℃ at a rate of 1.5 ℃/min;

step four: graphitizing at high temperature;

then, the interior of the graphite furnace is pumped to a vacuum state;

then, keeping the temperature of the graphite furnace at 2000 ℃ for 1-1.5 h;

Example 7

Embodiment 7 discloses a method for manufacturing an ultra-thick artificial graphite film, comprising the following steps:

the method comprises the following steps: preparing a PI film coiled material, namely winding the PI film on a graphite rod through a rewinding machine to obtain the PI film coiled material, wherein the gap between each layer of the PI film coiled material is 180 mu m, and the thickness of the PI film is 160;

step three: vacuum carbonization;

then, the inside of the carbonization furnace was raised from 550 ℃ to 9960 ℃ at a rate of 1.5 ℃/min;

then, the inside of the carbonization furnace was raised from 9960 ℃ to 1350 ℃ at a rate of 2.5 ℃/min;

step four: graphitizing at high temperature;

then, the interior of the graphite furnace is pumped to a vacuum state;

then, keeping the temperature of the graphite furnace at 2000 ℃ for 1-1.5 h;

Selecting 60 rolls of PI films with the thickness type of 90 mu m and equally dividing the PI films into 6 groups, equally dividing each group into 10 rolls, respectively selecting 10 rolls of PI films with the thickness types of 120 mu m and 160 mu m, respectively carrying out the manufacturing methods of the examples 1-5 and the conventional artificial graphite film manufacturing process on the 6 groups of PI films with the thickness type of 90 mu m to obtain the artificial graphite film, carrying out the manufacturing method of the example 6 on the 10 rolls of PI films with the thickness type of 120 mu m to obtain the artificial graphite film, carrying out the manufacturing method of the example 7 on the 10 rolls of PI films with the thickness type of 160 mu m to obtain the artificial graphite film, firstly observing the arching condition of the artificial graphite film, then measuring the thickness of the artificial graphite film, averaging the thicknesses of the 6 groups of PI films with the thickness type of 90 mu m and the thicknesses of the 10 rolls of PI films with the thickness types of 120 mu m and 160 mu m, respectively recording the thicknesses in the following table, and then counting the sum of salient points and bright points on the artificial graphite film of 3 meters before, the sum of the salient points and the bright points of 6 sets of PI films with the thickness type of 90 micrometers and the sum of the salient points and the bright points of 10 rolls of PI films with the thickness types of 120 micrometers and 160 micrometers are averaged and recorded in the following table respectively, then, each set of 6 sets of PI films with the thickness type of 90 micrometers is equally divided into two parts, each part is 5 rolls, 10 rolls of PI films with the thickness type of 120 micrometers are equally divided into two parts, each part is 5 rolls, 10 rolls of PI films with the thickness type of 160 micrometers are equally divided into two parts, each PI film with the thickness type of 90 micrometers is tested for bending resistance and heat conductivity, the PI films with the thickness type of 120 micrometers are tested for bending resistance and heat conductivity, the PI films with the thickness type of 160 micrometers are tested for bending resistance and heat conductivity, and the average value of the result of each part is recorded in the following table.

Table 1 artificial graphite film performance test data table

The bending resistance test steps of the artificial graphite film are as follows: cutting a sheet with the length of 5cm and the width of 2.54cm from the artificial graphite film coiled material as an experimental sample, fixing one end of the sheet, rotating the other end of the sheet to enable the sheet to rotate back and forth towards two sides by 90 degrees, wherein the rotating radius of the sheet is 5cm, the rotating frequency is 1 second, the sheet rotates by 90 degrees towards one side and then rotates by 180 degrees in the reverse direction, then the sheet rotates by 90 degrees in the reverse direction to the initial position and records the initial position, the rotating times of the sheet during fracture are recorded, and the more the rotating times of the sheet during fracture are, the better the bending resistance of the artificial graphite film is; the test of the heat conductivility of artifical graphite membrane is tested through laser heat conduction appearance, and artifical graphite membrane is under the condition of same thickness, and coefficient of heat conductivity is higher, and the heat conductivility of artifical graphite membrane is better, and artifical graphite membrane is under the condition of different thickness, and the product between the thickness of the heat conductivility of artifical graphite membrane and coefficient of heat conductivity is positive correlation.

The existing artificial graphite film is limited by process factors, only PI films with the thickness within the range of 90 microns can be processed, so that the thickness of the manufactured artificial graphite film is within 60 microns, and data in the table are observed and calculated.

In addition, in the embodiments 1 to 3, the temperature in the carbonization process and the graphitization process is gradually reduced, so that the temperature rise time in the carbonization and graphitization processes is prolonged, the PI film is fully carbonized and graphitized, and the corresponding data in the embodiments 1 to 3 in the table show that the bending resistance and the heat conductivity of the artificial graphite film are both remarkably improved, and the salient points, the bright points and the arch edge defects on the surface of the artificial graphite film are remarkably reduced; in the embodiments 3 to 5, the highest temperature rise temperature in the carbonization and graphitization processes is gradually increased, so that the PI film can be fully carbonized and graphitized, and the corresponding data in the above table in the embodiments 3 to 5 show that the bending resistance and the heat conductivity of the artificial graphite film are significantly improved, and the defects of bumps, bright spots and arching edges on the surface of the artificial graphite film are significantly reduced; in examples 5 to 7, the thickness of the PI film was increased, so that the thickness of the artificial graphite film was increased, and it can be known from the data in the above table that the bending resistance and the heat conductivity of the artificial graphite film were both significantly improved with the increase in the thickness of the artificial graphite film.

Claims

1. The manufacturing method of the super-thick artificial graphite film is characterized by comprising the following steps:

step two: loading, namely placing the PI film coiled material in a boat;

step three: vacuum carbonization;

firstly, feeding the boat into a carbonization furnace and closing a furnace door;

then, raising the temperature inside the carbonization furnace to 520-550 ℃ from the normal temperature at a speed of 5-7 ℃/min;

step four: graphitizing at high temperature;

then, the interior of the graphite furnace is pumped to a vacuum state;

then, filling inert protective gas into the graphite furnace;

then, raising the temperature inside the graphite furnace from the normal temperature to 1800-2000 ℃ at a speed of 10-12 ℃/min;

step five: and (3) calendering, namely pressing the graphitized film on a release film through a calendering process to obtain the ultra-thick artificial graphite film.

2. The method for manufacturing the ultra-thick artificial graphite film according to claim 1, wherein in the first step, the gap between each layer of the PI film coil is 160-180 μm.

3. The method for manufacturing the ultra-thick artificial graphite film according to claim 1, wherein in the first step, the thickness of the PI film is 80-160 μm.

4. The method of claim 1, wherein in the second step, the boat is divided into three layers, and 12 rolls of PI film coils are placed on each layer.

5. The method of claim 1, wherein the inside of the carbonization furnace is evacuated by a vacuum pump unit, the degree of vacuum in the carbonization furnace is controlled to 500pa or less, and the pressure is maintained for 30min or more.

6. The method of claim 1, wherein in step four, the inert shielding gas is helium, argon or xenon.