A kind of graphene thermal conductive insulating masterbatch and preparation method thereof

Abstract

The present invention belongs to the technical field of thermal conductive materials, and in particular, relates to a graphene thermal conductive insulating masterbatch and a preparation method thereof. The present invention performs expansion and heat insulation treatment on expandable graphite to obtain expanded graphite; the expanded graphite is mixed with a nonionic dispersant to obtain a mixture; the obtained mixture is mixed with a polycarbonate masterbatch and then subjected to heat treatment to obtain a multilayer graphene modified masterbatch; the obtained multilayer graphene modified masterbatch is mixed with a thermal conductive powder to obtain a mixture; the obtained mixture is extruded and granulated to obtain a graphene thermal conductive insulating masterbatch. The present invention prepares a plastic masterbatch by compounding graphene and thermal conductive powder, which can increase the thermal conductivity of the plastic itself by 3 to 4 times the original value. The graphene in the graphene modified masterbatch prepared by the present invention is not easy to aggregate again and is well dispersed.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal conductive materials, and in particular to a graphene thermal conductive insulating masterbatch and a preparation method thereof. Background Art

[0002] High temperature can have a harmful effect on the stability, reliability and life of electronic components, so it is very important to ensure that the heat generated by the heat-generating electronic components can be discharged in a timely manner. Among them, aluminum alloy heat dissipation technology is the most mature and occupies a large share of the market. Now, polymer-based heat dissipation composite materials have attracted attention due to their low cost, easy processing and molding, light weight, and short production cycle.

[0003] Improving the thermal conductivity of polymers by adding thermal conductive materials to them is currently the most effective and convenient way. Graphene has very good thermal conductivity. The thermal conductivity of pure, defect-free single-layer graphene is as high as 5300W / mK, which is the carbon material with the highest thermal conductivity to date. It can be seen that graphene has great potential in the field of heat dissipation. However, due to its characteristics of being difficult to disperse, easy to agglomerate, and expensive, when it is made into a graphene-based thermal conductive and heat dissipating composite material, not only is its thermal conductivity average, but it is also expensive. Summary of the invention

[0004] The purpose of the present invention is to provide a graphene thermally conductive insulating masterbatch and a preparation method thereof, so as to solve the characteristics of poor thermal conductivity and high price.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a graphene thermally conductive insulating masterbatch, comprising the following steps:

[0007] (1) subjecting expandable graphite to an expansion and heat preservation treatment to obtain expanded graphite;

[0008] (2) mixing the expanded graphite with a nonionic dispersant to obtain a mixture;

[0009] (3) mixing the obtained mixture with a polycarbonate masterbatch and then heat treating the mixture to obtain a multilayer graphene modified masterbatch;

[0010] (4) mixing the obtained multilayer graphene modified masterbatch and thermal conductive powder to obtain a mixture;

[0011] (5) Extruding and granulating the obtained mixture to obtain graphene thermal conductive insulating masterbatch.

[0012] Preferably, the temperature of the puffing and heat preservation treatment in step (1) is 310-350° C., and the time is 10-30 min;

[0013] The expandable graphite sheet has a thickness of 20 to 30 μm.

[0014] Preferably, the mass ratio of the expanded graphite to the nonionic dispersant in step (2) is (30-40):(30-45);

[0015] The nonionic dispersant comprises one or more of polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene wax powder, polytetrafluoroethylene powder and polypropylene wax powder.

[0016] Preferably, in step (3), the mass ratio of the polycarbonate masterbatch to the nonionic dispersant is (900-1000): (30-45);

[0017] The heat treatment time is 310-350° C. and the time is 20-40 minutes.

[0018] Preferably, in step (4), the mass ratio of the thermally conductive powder to the nonionic dispersant is (600-700): (30-45);

[0019] The thermal conductive powder comprises one or more of boron nitride, silicon carbide, aluminum powder and aluminum oxide, and has a particle size of 50 to 100 nm.

[0020] Preferably, in step (4), the thermally conductive powder is divided into three parts, and the obtained multilayer graphene modified masterbatch is mixed with the three parts of thermally conductive powder in sequence.

[0021] Preferably, the nozzle temperature of the extruder used for extrusion granulation in step (5) is 340-360°C, the temperature of the first section is 320-340°C, the temperature of the second section is 300-320°C, and the feeding temperature is 280-300°C.

[0022] The present invention also provides graphene thermally conductive insulating masterbatch obtained by the preparation method.

[0023] The beneficial effects of the present invention are as follows:

[0024] The present invention uses graphene and thermal conductive powder to prepare plastic masterbatch, which can make the thermal conductivity of the plastic itself 3 to 4 times higher than the original. The graphene in the graphene modified masterbatch prepared by the present invention is not easy to aggregate again and is well dispersed. The graphene forms an interface structure with stable performance with PC, and forms a thermal conductive and heat dissipation network structure with the thermal conductive powder, so that the heat dissipation performance of the graphene is maximized. Moreover, the graphene thermal conductive masterbatch prepared by this method is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The graphene thermally conductive insulating masterbatch product obtained in Example 1;

[0026] Figure 2This is a SEM image of the graphene thermally conductive insulating masterbatch product obtained in Example 1. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing a graphene thermally conductive insulating masterbatch, comprising the following steps:

[0028] (1) subjecting expandable graphite to an expansion and heat preservation treatment to obtain expanded graphite;

[0029] (2) mixing the expanded graphite with a nonionic dispersant to obtain a mixture;

[0030] (3) mixing the obtained mixture with a polycarbonate (PC) masterbatch and then heat treating the mixture to obtain a multilayer graphene modified masterbatch;

[0031] (4) mixing the obtained multilayer graphene modified masterbatch and thermal conductive powder to obtain a mixture;

[0032] (5) Extruding and granulating the obtained mixture to obtain graphene thermal conductive insulating masterbatch.

[0033] In the present invention, the temperature of the expansion and heat preservation treatment in step (1) is 310-350°C, preferably 320-340°C, and more preferably 330°C; the time is 10-30 min, preferably 15-25 min, and more preferably 20 min; the thickness of the expandable graphite sheet is 20-30 μm, preferably 24-28 μm, and more preferably 25-26 μm.

[0034] In the present invention, the mass ratio of the expanded graphite to the nonionic dispersant in step (2) is (30-40):(30-45), preferably (34-36):(35-40); the nonionic dispersant comprises one or more of polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene wax powder, polytetrafluoroethylene micropowder and polypropylene wax powder.

[0035] In the present invention, the mixing in step (2) can be specifically high-speed shear mixing for 4 to 6 minutes, preferably 5 minutes.

[0036] In the present invention, the mass ratio of the polycarbonate masterbatch and the nonionic dispersant in step (3) is (900-1000): (30-45), preferably (940-9700): (35-40); the heat treatment time is 310-350°C, preferably 320-340°C, and more preferably 330°C; the time is 20-40min, preferably 25-35min, and more preferably 30min.

[0037] In the present invention, the presence of the nonionic dispersant establishes a connection between the expandable graphite and the PC masterbatch. When the expandable graphite and the PC masterbatch are mixed, it can assist the expanded graphite with opened flakes to be peeled off into graphene, and also assist the dispersion of graphene in the PC masterbatch.

[0038] In the present invention, the mixing in step (3) can be specifically shear mixing for 15 to 25 minutes, preferably 20 minutes.

[0039] The present invention uses 310-350° C. to expand expandable graphite, obtain expanded graphite with opened lamellae, and can also make the PC more fluid and expand its volume, so that the expanded graphite is easier to be peeled off, and the peeled graphene can be well dispersed and is not easy to re-aggregate.

[0040] In the present invention, the mass ratio of the thermally conductive powder and the non-ionic dispersant in step (4) is (600-700): (30-45), preferably (650-670): (35-40); the thermally conductive powder comprises one or more of boron nitride, silicon carbide, aluminum powder and aluminum oxide, has high thermal conductivity, good heat dissipation performance, and good wear resistance, and the particle size is 50-100 nm, preferably 60-80 nm.

[0041] In the present invention, in step (4), the thermally conductive powder is preferably divided into three parts, and the obtained multilayer graphene modified masterbatch is mixed with the three parts of thermally conductive powder in sequence; specifically, the first part of the thermally conductive powder is added to the multilayer graphene modified masterbatch and mixed for 3 to 6 minutes, and then the second part of the thermally conductive powder is added, and after mixing for 3 to 6 minutes, the last part is added and mixed for 15 to 23 minutes; preferably, the first part of the thermally conductive powder is added to the multilayer graphene modified masterbatch and mixed for 5 minutes, and then the second part of the thermally conductive powder is added, and after mixing for 5 minutes, the last part is added and mixed for 20 minutes.

[0042] In the present invention, the nozzle temperature of the extruder used for extrusion granulation in step (5) is 340-360°C, the temperature of the first section is 320-340°C, the temperature of the second section is 300-320°C, and the feeding temperature is 280-300°C. Preferably, the nozzle temperature is 350°C, the temperature of the first section is 330°C, the temperature of the second section is 310°C, and the feeding temperature is 290°C.

[0043] The present invention also provides graphene thermally conductive insulating masterbatch obtained by the preparation method.

[0044] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0045] Embodiment 1

[0046] The expandable graphite was placed in a puffing furnace and puffed at 310°C for 20 minutes.

[0047] 30 g of expanded graphite and 30 g of polyvinyl pyrrolidone were mixed by high-speed shearing for 5 min to obtain a mixture 1. The mixture 1 was introduced into 1000 g of PC masterbatch and sheared and mixed for 20 min, and heated to 320° C. and mixed for 30 minutes to obtain a graphene-modified masterbatch.

[0048] Weigh 700 g of thermal conductive powder (boron nitride) and divide the thermal conductive powder into three equal parts. Add one part of the thermal conductive powder to the graphene modified masterbatch and mix for 5 minutes, then add the second part of the thermal conductive powder, mix for 5 minutes, then add the last part and mix for 20 minutes to obtain a mixture II.

[0049] The mixture 2 is extruded and granulated through an extruder set at a nozzle temperature of 350°C, a first stage temperature of 330°C, a second stage temperature of 310°C, and a feed temperature of 290°C to obtain graphene thermally conductive insulating masterbatch.

[0050] After testing, the thermal conductivity of the graphene thermally conductive insulating masterbatch prepared in this embodiment is 15W / m·K. This thermal conductivity is 78.95 times that of the original PC masterbatch. -15 S / cm, in an insulating state.

[0051] Embodiment 2

[0052] The expandable graphite was placed in a puffing furnace and puffed at 320°C for 20 minutes.

[0053] 30 g of expanded graphite and 45 g of polyvinyl alcohol were mixed by high-speed shearing for 5 min to obtain a mixture 1. The mixture 1 was introduced into 1000 g of PC masterbatch and sheared and mixed for 20 min, and heated to 330° C. and mixed for 30 minutes to obtain a graphene-modified masterbatch.

[0054] Weigh 700 g of thermal conductive powder (silicon carbide) and divide the thermal conductive powder into three equal parts. Add one part of the thermal conductive powder to the graphene modified masterbatch and mix for 5 minutes, then add the second part of the thermal conductive powder, mix for 5 minutes, and heat the last part and mix for 20 minutes to obtain a second mixture.

[0055] The mixture 2 is extruded and granulated through an extruder set at a nozzle temperature of 350°C, a first stage temperature of 330°C, a second stage temperature of 310°C, and a feed temperature of 290°C to obtain graphene thermally conductive insulating masterbatch.

[0056] After testing, the thermal conductivity of the graphene thermal insulation masterbatch prepared in this embodiment is 15.6W / m·K. This thermal conductivity is 82.11 times that of the original PC masterbatch. -15 S / cm, in an insulating state.

[0057] Comparative Example 1

[0058] The expandable graphite was placed in a puffing furnace and puffed at 320°C for 20 minutes.

[0059] 30 g of expanded graphite and 45 g of polyvinyl alcohol were mixed by high-speed shearing for 5 min to obtain a mixture 1. The mixture 1 was introduced into 1000 g of PC masterbatch and sheared and mixed for 20 min, and heated to 330° C. and mixed for 30 minutes to obtain a graphene-modified masterbatch.

[0060] The graphene modified masterbatch was extruded and granulated by an extruder set at a nozzle temperature of 350°C, a first stage temperature of 330°C, a second stage temperature of 310°C, and a feed temperature of 290°C.

[0061] After testing, the thermal conductivity of the graphene modified masterbatch prepared in this embodiment is 0.72W / m·K. This thermal conductivity is 3.79 times that of the original PC masterbatch. -15 S / cm, in an insulating state.

[0062] Comparative Example 2

[0063] Weigh 700g of thermal conductive powder (silicon carbide) and divide it into three equal parts. Add one part of the thermal conductive powder to the PC masterbatch and mix for 5 minutes, then add the second part of the thermal conductive powder, mix for 5 minutes, and heat the last part and mix for 20 minutes.

[0064] The obtained mixture is extruded and granulated through an extruder set at a nozzle temperature of 350°C, a first stage temperature of 330°C, a second stage temperature of 310°C, and a feed temperature of 290°C to obtain a thermally conductive insulating masterbatch.

[0065] After testing, the thermal conductivity of the thermally conductive insulating masterbatch prepared in this embodiment is 4.7W / m·K. This thermal conductivity is 19.95 times that of the original PC masterbatch. -16 S / cm, in an insulating state.

[0066] Comparative Example 3

[0067] 30 g of expandable graphite and 1000 g of PC masterbatch were shear-mixed for 20 min to obtain a mixture.

[0068] Weigh 700 g of thermally conductive powder (silicon carbide) and divide the thermally conductive powder into three equal parts. Add one part of the thermally conductive powder to the mixture and mix for 5 minutes, then add the second part of the thermally conductive powder, mix for 5 minutes, and heat the last part and mix for 20 minutes to obtain a second mixture.

[0069] The mixture 2 is extruded and granulated through an extruder set at a nozzle temperature of 350°C, a first stage temperature of 330°C, a second stage temperature of 310°C, and a feed temperature of 290°C to obtain a thermally conductive insulating masterbatch.

[0070] After testing, the thermal conductivity of the thermally conductive insulating masterbatch prepared in this embodiment is 6.4W / m·K. This thermal conductivity is 36.68 times that of the original PC masterbatch. -16 S / cm, in an insulating state.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a graphene thermally conductive insulating masterbatch, characterized in that: The following steps are included: (1) subjecting expandable graphite to an expansion and heat preservation treatment to obtain expanded graphite; (2) mixing the expanded graphite with a nonionic dispersant to obtain a mixture; (3) mixing the obtained mixture with a polycarbonate masterbatch and then heat treating the mixture to obtain a multilayer graphene modified masterbatch; (4) mixing the obtained multilayer graphene modified masterbatch and thermal conductive powder to obtain a mixture; (5) extruding and granulating the obtained mixed material to obtain graphene thermal conductive insulating masterbatch; The mixing in step (3) is shear mixing for 15 to 25 minutes; the temperature of the heat treatment is 310 to 350°C.

2. The preparation method according to claim 1, characterized in that: The temperature of the puffing and heat preservation treatment in step (1) is 310-350°C and the time is 10-30 minutes; The expandable graphite sheet has a thickness of 20-30 μm.

3. The preparation method according to claim 1 or 2, characterized in that: The mass ratio of the expanded graphite to the nonionic dispersant in step (2) is (30-40):(30-45); The nonionic dispersant comprises one or more of polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene wax powder, polytetrafluoroethylene powder and polypropylene wax powder.

4. The preparation method according to claim 3, characterized in that: In step (3), the mass ratio of polycarbonate masterbatch to nonionic dispersant is (900-1000): (30-45); The heat treatment time is 20 to 40 minutes.

5. The preparation method according to claim 1 or 4, characterized in that: In step (4), the mass ratio of thermal conductive powder to non-ionic dispersant is (600-700): (30-45); The thermal conductive powder comprises one or more of boron nitride, silicon carbide, aluminum powder and aluminum oxide, and has a particle size of 50-100 nm.

6. The preparation method according to claim 5, characterized in that: In step (4), the thermally conductive powder is divided into three parts, and the obtained multilayer graphene modified masterbatch is mixed with the three parts of thermally conductive powder in sequence.

7. The preparation method according to claim 1 or 6, characterized in that: The nozzle temperature of the extruder used for extrusion granulation in step (5) is 340-360°C, the temperature of the first section is 320-340°C, the temperature of the second section is 300-320°C, and the feeding temperature is 280-300°C.

8. The graphene thermally conductive insulating masterbatch obtained by the preparation method according to any one of claims 1 to 7.

Images