阅读说明：本技术 非金属导热器及其制造方法 (Non-metal heat conductor and its manufacturing method ) 是由 万虎 冯先强 于 2020-04-26 设计创作，主要内容包括：本申请提供了提供一种非金属导热器及其制造方法,其中,制成非金属导热器的材料包括以下重量份数的原料：导热填料200～500份；高分子粘结剂50～80份；其中,导热填料包括球形石墨、鳞片石墨、膨胀石墨或炭黑中的至少一种。即非金属导热材料各组分的含量为导热填料60％～90％和高分子粘结剂40％～10％。本申请提供的非金属导热器,制成非金属导热器的材料只包括导热填料和高分子粘结剂两种成分,无需加入阻燃剂、分散剂、增塑剂等助剂,一方面,降低了工艺难度,从而缩短了加工周期,提高了产品的生产效率,另一方面,减少了材料的种类,降低了产品的生产制造成本。(The application provides a non-metal heat conductor and a manufacturing method thereof, wherein the non-metal heat conductor is made of the following raw materials in parts by weight: 200-500 parts of heat-conducting filler; 50-80 parts of a high-molecular binder; wherein the heat conductive filler comprises at least one of spherical graphite, flake graphite, expanded graphite or carbon black. Namely, the contents of all components of the non-metal heat conduction material are 60 to 90 percent of heat conduction filler and 40 to 10 percent of high molecular binder. The application provides a nonmetal heat conduction device, the material of making nonmetal heat conduction device only includes two kinds of compositions of heat conduction filler and polymer binder, need not to add auxiliaries such as fire retardant, dispersant, plasticizer, on the one hand, has reduced the technology degree of difficulty to shorten processing cycle, improved the production efficiency of product, on the other hand, reduced the kind of material, reduced the manufacturing cost of product.)

1. The nonmetal heat conductor is characterized in that the nonmetal heat conductor is made of the following raw materials in parts by weight:

200-500 parts of heat-conducting filler;

50-80 parts of a high-molecular binder;

wherein the thermally conductive filler comprises at least one of spherical graphite, flake graphite, expanded graphite, or carbon black.

2. The non-metallic heat conductor of claim 1,

the fixed carbon content of the heat-conducting filler is more than 90%.

3. The non-metallic heat conductor of claim 1,

the particle size of the spherical graphite, the crystalline flake graphite and the carbon black is 100-500 meshes, and the original expansion volume of the expanded graphite is 100-600 ml/g.

4. The non-metallic heat conductor of claim 1,

the melt index of the high-molecular binder is 12g/10min-25g/10 min.

5. The non-metallic heat conductor of claim 1,

the high-molecular binder comprises ultrahigh-molecular-weight polyethylene and low-density polyethylene, wherein the ratio of the ultrahigh-molecular-weight polyethylene to the low-density polyethylene is 1: 1-1: 3.

6. The non-metallic heat conductor of claim 5,

the particle size of the ultra-high molecular weight polyethylene is 300-800 meshes, and the particle size of the low density polyethylene is 300-800 meshes.

7. A method for manufacturing a non-metallic heat conductor, comprising the steps of:

step S1, drying the powder of the heat-conducting filler and the powder of the polymer binder;

step S2, uniformly mixing 200-500 parts by weight of the dried heat-conducting filler and 50-80 parts by weight of the dried polymer binder to form a mixture;

step S3, loading the mixture into a cavity of a mold, gradually heating to reach a preset temperature, and sintering the mixture in the mold by keeping the temperature and pressure for a set time;

and step S4, cooling the sintered mould, and demoulding to obtain the nonmetal heat conductor.

8. The method of claim 7, wherein the step of forming the non-metallic heat conductor,

the step S2 specifically includes:

step S21, adding 200-500 parts by weight of the heat-conducting filler and 50-80 parts by weight of the polymer binder into a mixer;

step S22, mixing the heat-conducting filler and the polymer binder for 15-30 seconds at the rotating speed of 1000-5000 r/min by the mixer;

and step S23, repeating the step S22 for 3-6 times to form the mixture.

9. The method of claim 7, wherein the step of forming the non-metallic heat conductor,

the step S3 specifically includes:

step S31, loading the mixture into a cavity of the mold through an automatic filling device;

step S32, pressurizing the mixture in the cavity;

and step S33, carrying out heat preservation and pressure maintaining on the mould filled with the mixture for 60-100 min at the temperature of 200-400 ℃ for sintering.

10. The method of claim 7, wherein the step of forming the non-metallic heat conductor,

the temperature increase rate of the sintering in step S33 is 1-5 deg.C/min.

Technical Field

The application relates to the technical field of non-metal heat dissipation materials, in particular to a non-metal heat conductor made of non-metal materials and a manufacturing method of the non-metal heat conductor.

Background

The statements in this application as background to the related art related to this application are merely provided to illustrate and facilitate an understanding of the contents of the present application and are not to be construed as an admission that the applicant expressly or putatively admitted the prior art of the filing date of the present application at the first filing date.

In order to ensure that the electronic components work normally with high reliability for a long time, the junction temperature of the components must be prevented from rising continuously, and therefore, a heat dissipation device needs to be added on the electronic components to perform effective heat dissipation. In the prior art, a heat dissipation device made of a non-metal composite material generally uses a high polymer material as a base material, and various high-thermal-conductivity fillers are added into the non-metal composite material, but because the intrinsic thermal conductivity of the high polymer base material is extremely low, enough thermal-conductivity fillers need to be added to form a thermal-conductivity network structure, but the processing fluidity of the material is greatly reduced by adding a large amount of thermal-conductivity fillers, so that the molding is difficult, and the qualification rate of the product is not high.

Disclosure of Invention

The application provides a nonmetal heat conductor and a manufacturing method thereof, and the nonmetal heat conductor has the characteristics of light weight, good heat conducting effect, easiness in forming and the like.

Embodiments of the first aspect of the present application provide a non-metallic heat conductor, and a material of which the non-metallic heat conductor is made includes the following raw materials in parts by weight:

200-500 parts of heat-conducting filler;

50-80 parts of a high-molecular binder;

wherein the thermally conductive filler comprises at least one of spherical graphite, flake graphite, expanded graphite, or carbon black.

The application provides a non-metallic heat conductor, the material of making non-metallic heat conductor chooses for use graphite as heat conduction filler, graphite's coefficient of heat conductivity is high, the lubricity is good, be convenient for mix and pack, and have better fire behaviour, thereby make the non-metallic heat conductor who makes need not to carry out surface treatment, naturally have the best surface corrosion resisting property, and be higher than the emissivity of metal far away, avoided the environmental pollution who brings by secondary surface machining, cost increase scheduling problem. Meanwhile, the advantages of light weight, convenience in processing, high degree of freedom of structural design, low relative cost and the like are also considered. In addition, the polymer binder melts in the high-temperature sintering process, wets the contact surface and the gap between the heat-conducting fillers, and is cooled to room temperature after high-temperature sintering, and the molten polymer binder fluid is solidified to form the nonmetal heat conductor with high mechanical strength. In addition, the material for preparing the nonmetal heat conductor only comprises two components of a heat-conducting filler and a high-molecular binder, and auxiliary agents such as a flame retardant, a dispersing agent, a plasticizer and the like are not required to be added, so that on one hand, the process difficulty is reduced, the processing period is shortened, the production efficiency of the product is improved, on the other hand, the types of the material are reduced, and the production and manufacturing cost of the product is reduced.

Optionally, the thermally conductive filler has a fixed carbon content greater than 90%.

Optionally, the particle size of the spherical graphite, the flake graphite and the carbon black is 100 to 500 meshes, and the original expansion volume of the expanded graphite is 100 to 600 ml/g.

Optionally, the melt index of the polymeric binder is 12g/10min-25g/10 min.

Optionally, the high molecular binder comprises ultrahigh molecular weight polyethylene and low density polyethylene, wherein the ratio of the ultrahigh molecular weight polyethylene to the low density polyethylene is 1: 1-1: 3.

Optionally, the particle size of the ultra-high molecular weight polyethylene is 300-800 meshes, and the particle size of the low density polyethylene is 300-800 meshes.

Embodiments of the second aspect of the present application provide a method for manufacturing a non-metallic heat conductor, comprising the steps of:

step S1, drying the powder of the heat-conducting filler and the powder of the polymer binder;

step S2, uniformly mixing 200-500 parts by weight of the dried heat-conducting filler and 50-80 parts by weight of the dried polymer binder to form a mixture;

step S3, loading the mixture into a cavity of a mold, gradually heating to reach a preset temperature, and sintering the mixture in the mold by keeping the temperature and pressure for a set time;

and step S4, cooling the sintered mould, and demoulding to obtain the nonmetal heat conductor.

The manufacturing method provided by the application comprises the steps of drying powder of the heat-conducting filler and powder of the high-molecular binder; and then mixing the dried powder of the heat-conducting filler and the powder of the high-molecular binder, then filling the mixed material into a mold, and then sintering at a high temperature, wherein in the high-temperature sintering process, the high-molecular binder melts and wets contact surfaces and gaps between the heat-conducting fillers, cooling to room temperature after sintering at a high temperature, and the molten high-molecular binder is solidified to form the nonmetal heat conductor with high mechanical strength. By adopting the sintering and forming process, the problems of poor processing fluidity, difficult forming and the like caused by excessive addition of the heat-conducting filler are solved by mixing, recharging and sintering and forming the heat-conducting filler and the high-molecular binder, so that the weight percentage of the heat-conducting filler is maximized, and the heat conductivity coefficient of the device material is further improved.

Optionally, the step S2 specifically includes:

step S21, adding 200-500 parts by weight of the heat-conducting filler and 50-80 parts by weight of the polymer binder into a mixer;

step S22, mixing the heat-conducting filler and the polymer binder for 15-30 seconds at the rotating speed of 1000-5000 r/min by the mixer;

and step S23, repeating the step S22 for 3-6 times to form the mixture.

Optionally, the step S3 specifically includes:

step S31, loading the mixture into a cavity of the mold through an automatic filling device;

step S32, pressurizing the mixture in the cavity;

and step S33, carrying out heat preservation and pressure maintaining on the mould filled with the mixture for 60-100 min at the temperature of 200-400 ℃ for sintering.

Optionally, the heating rate of sintering in step S33 is 1 to 5 ℃/min.

Additional aspects and advantages of the present application will be set forth in part in the description which follows, or may be learned by practice of the present application.

Drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a flow chart of a first embodiment of a method of manufacturing a non-metallic heat conductor as described herein;

FIG. 2 is a flow chart of a second embodiment of a method of manufacturing a non-metallic heat conductor as described herein;

FIG. 3 is a flow chart of a third embodiment of a method of manufacturing a non-metallic heat conductor as described herein.

Detailed Description

In order that the above objects, features and advantages of the present application can be more clearly understood, the present application will be described in further detail with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.

The following discussion provides a number of embodiments of the application. While each embodiment represents a single combination of applications, the various embodiments of the disclosure may be substituted or combined in any combination, and thus, the disclosure is intended to include all possible combinations of the same and/or different embodiments of what is described. Thus, if one embodiment comprises A, B, C and another embodiment comprises a combination of B and D, then this application should also be considered to comprise an embodiment that comprises A, B, C, D in all other possible combinations, although this embodiment may not be explicitly recited in the text below.

The non-metal heat conduction material that this application first aspect provided, this non-metal heat conduction material is used for making non-metal heat conductor, and non-metal heat conduction material includes the raw materials of following parts by weight: 200-500 parts of heat-conducting filler. 50-80 parts of a high-molecular binder. Namely, the percentage content of each component of the non-metal heat conduction material is 60 percent to 90 percent of heat conduction filler and 40 percent to 10 percent of polymer binder.

The thermally conductive filler includes at least one of spheroidal graphite, flake graphite, expanded graphite, or carbon black.

The application provides a nonmetal heat conduction device, the material of making nonmetal heat conduction device only includes two kinds of compositions of heat conduction filler and polymer binder, need not to add auxiliaries such as fire retardant, dispersant, plasticizer, on the one hand, has reduced the technology degree of difficulty to shorten processing cycle, improved the production efficiency of product, on the other hand, reduced the kind of material, reduced the manufacturing cost of product.

The spherical graphite has the characteristics of good conductivity, high crystallinity, low cost and the like.

The flake graphite has good high temperature resistance, electric conductivity, heat conduction, lubrication, plasticity, acid and alkali resistance and other properties.

The expanded graphite has the following characteristics: 1. strong pressure resistance, flexibility, plasticity and self-lubricating property. 2. High resistance to high and low temp, corrosion and radiation. 3. Extremely strong shock resistance. 4. Extremely strong electrical conductivity. 5. Strong anti-aging and anti-distortion properties. 6. Can resist melting and infiltration of various metals. 7. No toxicity, no carcinogen and no harm to environment.

The carbon black has the characteristics of light weight, low cost and the like.

The graphite has high heat conductivity coefficient, good lubricity, convenient mixing and filling and better flame retardant property, so that the nonmetal heat conductor made of the material adopting the graphite as the filler does not need surface treatment, has excellent surface corrosion resistance naturally and radiation coefficient far higher than that of metal, and avoids the problems of environmental pollution, cost increase and the like caused by secondary surface processing. Meanwhile, the advantages of light weight, convenience in processing, high degree of freedom of structural design, low relative cost and the like are also considered.

The polymer binder melts in the high-temperature sintering process, wets the contact surface and the gap between the heat-conducting fillers, can well bond heat-conducting filler particles, enables the metal heat conductor to be easy to form, cools to room temperature after high-temperature sintering, and the molten polymer binder fluid is solidified to form the nonmetal heat conductor with high mechanical strength, so that the service life of the product is ensured, and the market competitiveness of the product is increased.

One skilled in the art can select one or more of spherical graphite, flake graphite, expanded graphite or carbon black to prepare the heat conductive filler according to specific requirements. In addition, the carbon-based filler has extremely high specific surface area, mechanical property and excellent thermal property, and ensures the heat conduction effect of the nonmetal heat conductor.

In one embodiment of the present application, the fixed carbon content of the thermally conductive filler is greater than 90%.

In the embodiment, the heat-conducting filler contains impurities which can be burnt out in the high-temperature sintering process, the burnt-out impurities volatilize, and gaps can be formed on the nonmetal heat conductor after volatilization; the fixed carbon content of the heat-conducting filler is more than 90%, namely, the impurities in the heat-conducting filler are less than 10%, so that the content of air holes in the nonmetal heat conductor is reduced, and the overall strength of the nonmetal heat conductor is ensured. In addition, the graphite with the fixed carbon content of more than 90 percent is selected as the heat-conducting filler, so that the heat-conducting filler has high heat conductivity coefficient, good lubricity, convenient mixing and filling and better flame retardant property.

In one embodiment of the present application, the spherical graphite, the flake graphite and the carbon black have a particle size of 100 to 500 mesh, and the expanded graphite has an original expanded volume of 100 to 600 ml/g.

In this embodiment, the powder granule of heat conduction filler includes multiple particle diameter, and the particle diameter of heat conduction filler is in 100 ~ 500 meshes, and the less granule of particle diameter can be filled between the great granule of particle diameter to the nonmetal heat conduction ware that the material that makes that the messenger adopts graphite as filler has high mechanical strength, has guaranteed promptly that nonmetal heat conduction ware has higher mechanical strength, has guaranteed the reliability in utilization of nonmetal heat conduction ware, and then has prolonged the life of nonmetal heat conduction ware. The expanded graphite can expand in the sintering process, so that gaps among other particles are filled, and the nonmetal heat conductor is ensured to have high mechanical strength.

In one embodiment of the present application, the polymeric binder has a melt index of 12g/10min to 25g/10 min. The melt index is a value representing the fluidity of the material at the time of processing, and if the melt index of the polymer binder is less than 12g/10min, the fluidity of the polymer binder is poor, and the polymer binder cannot effectively wet the contact surfaces and gaps between the heat conductive fillers during the high-temperature sintering process, resulting in that the polymer binder cannot sufficiently bind the particles of the heat conductive fillers. If the melt index of the high-molecular binder is greater than 25g/10min, the high-molecular binder has strong fluidity, and in the high-temperature sintering process, the high-molecular binder cannot well stay among particles of the heat-conducting filler after wetting contact surfaces and gaps among the heat-conducting filler, and the high-molecular binder cannot sufficiently bond the particles of the heat-conducting filler. Therefore, the melt index of the high polymer binder is within 12g/10min-25g/10min, the high polymer binder is melted in the high-temperature sintering process, the melted high polymer binder can fully wet the contact surfaces and gaps between the heat-conducting fillers, the high-temperature sintered high polymer binder is cooled to room temperature, and the fluid of the melted high polymer binder is solidified to form the nonmetal heat conductor with high mechanical strength.

The ultra-high molecular weight polyethylene has outstanding impact resistance, stress cracking resistance, high-temperature creep resistance, low friction coefficient, self-lubrication, excellent chemical corrosion resistance, fatigue resistance, noise damping property, nuclear radiation resistance and the like. The molecular weight of the ultra-high molecular weight polyethylene is not less than 150 ten thousand, and the melting temperature is 130-140 ℃.

The low-density polyethylene has light weight, good flexibility, extensibility, transparency, cold resistance and processability; the chemical stability is good, and the paint can resist acid, alkali and salt aqueous solution; the electric insulation and the air permeability are good; the low density polyethylene has soft property, good extensibility, electric insulation, chemical stability, processability and low temperature resistance. The melting point of the low-density polyethylene is 110-115 ℃.

In one embodiment of the present application, the polymeric binder comprises ultra high molecular weight polyethylene and low density polyethylene. The method is characterized in that mixed powder of ultrahigh molecular weight polyethylene and low density polyethylene is selected as a high molecular binder, the high molecular binder has excellent wear resistance, self-lubricating property, impact resistance, corrosion resistance and the like, when the high temperature reaches the melting point in the hot-pressing sintering process, the ultrahigh molecular weight polyethylene and low density polyethylene powder are melted and show good fluidity, the ultrahigh molecular weight polyethylene and low density polyethylene powder are further promoted to be cast by a heat-preserving and pressure-maintaining process, contact surfaces and gaps among heat-conducting fillers are wetted, then the ultrahigh molecular weight polyethylene and low density polyethylene powder are cooled to room temperature, and the melted ultrahigh molecular weight polyethylene and low density polyethylene fluid are solidified to form the metal heat conductor with high mechanical strength.

In one embodiment of the present application, the ratio of the ultra-high molecular weight polyethylene to the low density polyethylene is 1:1 to 1: 3. That is, the content of each component of the polymer binder is 25% to 50% of ultra-high molecular weight polyethylene and 50% to 75% of low density polyethylene, and if the content of the low density polyethylene is less than 50%, the flow shape of the polymer binder in a molten state is poor, and the polymer binder cannot effectively wet the contact surfaces and gaps between the heat conductive fillers, so that the polymer binder cannot sufficiently bind the particles of the heat conductive fillers. If the content of the low-density polyethylene is higher than 75%, the fluidity of the polymer binder in a molten state is strong, and the polymer binder cannot well stay among the particles of the heat-conducting filler after wetting the contact surfaces and gaps among the heat-conducting fillers in the high-temperature sintering process, so that the polymer binder cannot sufficiently bind the particles of the heat-conducting filler. Therefore, the ratio of the ultrahigh molecular weight polyethylene to the low density polyethylene is 1: 1-1: 3, the high molecular binder is melted in the high-temperature sintering process, the melted high molecular binder can fully wet contact surfaces and gaps between the heat-conducting fillers, the high-temperature sintered high molecular binder is cooled to room temperature, and the melted high molecular binder is solidified to form the nonmetal heat conductor with high mechanical strength.

In one embodiment of the present application, the ultra-high molecular weight polyethylene has a particle size of 300 to 800 mesh, and the low density polyethylene has a particle size of 300 to 800 mesh. The high-temperature sintering device has the advantages that the high-molecular binder is guaranteed to have smaller particle size particles, the high-molecular binder can be quickly melted in the high-temperature sintering process, and the high-molecular binder can quickly wet contact surfaces and gaps between the heat-conducting fillers, so that the high-temperature sintering time is shortened, the production efficiency of products is improved, and the production and manufacturing cost of the nonmetal heat conductor is reduced.

As shown in fig. 1, a method for manufacturing a non-metallic heat conductor according to an embodiment of the second aspect of the present application includes the following steps:

and step S1, drying the powder of the heat-conducting filler and the powder of the high-molecular binder.

And step S2, uniformly mixing 200-500 parts by weight of dried heat-conducting filler and 50-80 parts by weight of dried polymer binder to form a mixture.

And step S3, loading the mixture into a cavity of a mold, gradually heating to reach a preset temperature, and then carrying out heat preservation and pressure maintaining within a set time to sinter the mixture in the mold.

And step S4, cooling the sintered die, and demolding to obtain the nonmetal heat conductor.

The manufacturing method provided by the application comprises the steps of drying powder of the heat-conducting filler and powder of the high-molecular binder; and then mixing the dried powder of the heat-conducting filler and the powder of the high-molecular binder, then filling the mixed material into a mold, and then sintering at a high temperature, wherein in the high-temperature sintering process, the high-molecular binder melts and wets contact surfaces and gaps between the heat-conducting fillers, cooling to room temperature after sintering at a high temperature, and the molten high-molecular binder is solidified to form the nonmetal heat conductor with high mechanical strength. By adopting the sintering and forming process, the problems of poor processing fluidity, difficult forming and the like caused by excessive addition of the heat-conducting filler are solved by mixing, recharging and sintering and forming the heat-conducting filler and the high-molecular binder, so that the weight percentage of the heat-conducting filler is maximized, and the heat conductivity coefficient of the device material is further improved.

As shown in fig. 2, in an embodiment of the present application, step S2 specifically includes:

step S21, adding 200-500 parts by weight of heat conducting filler and 50-80 parts by weight of polymer binder into a mixer.

And step S22, mixing the heat-conducting filler and the high polymer adhesive for 15-30 seconds at the rotating speed of 1000-5000 r/min by the mixer.

And step S23, repeating the step S22 for 3-6 times to form a mixture.

In this embodiment, the above operation can fully ensure the sufficient mixing of the heat conductive filler and the polymer binder, and ensure that the polymer binder can fully wet the contact surface and the gap between the heat conductive fillers after melting, thereby ensuring the uniformity of the manufactured non-metal heat conductor and ensuring that the non-metal heat conductor has high mechanical strength.

As shown in fig. 3, in an embodiment of the present application, step S3 specifically includes:

and step S31, filling the mixture into the cavity of the mold through an automatic filling device.

And step S32, pressurizing the mixture in the cavity.

And step S33, carrying out heat preservation and pressure maintaining on the mould filled with the mixture for 60-100 min at the temperature of 200-400 ℃ for sintering.

In this embodiment, automatic filler device can be vibrating device, and vibrating device sets up under the workstation of mould, and in the in-process of adding the mixture in to the die cavity, vibrates the mould simultaneously, and the vibration can guarantee that the mixture that adds in the die cavity is compacter, improves tap density, and can improve the efficiency of filling of mixture, has improved the production efficiency of product, and then has reduced the manufacturing cost of product. In addition, the mixture is subjected to pressurization treatment, so that the mixture added into the cavity can be improved to be more compact, the manufactured nonmetal heat conductor is ensured to have higher strength, namely, the nonmetal heat conductor is ensured to have higher mechanical strength, the use reliability of the nonmetal heat conductor is ensured, and the service life of the nonmetal heat conductor is further prolonged.

In one embodiment of the present application, the temperature increase rate of the sintering in step S33 is 1 deg.C/min to 5 deg.C/min.

In the embodiment, if the temperature rise rate of the sintering is less than 1 ℃/min, the temperature rise of the sintering is too slow, so that the high-temperature sintering time is prolonged, the production efficiency of the product is reduced, and the production and manufacturing cost of the non-metal heat conductor is further improved. If the temperature rise rate of sintering is more than 5 ℃/min, the temperature rise of sintering is too fast, the heat-conducting filler is easy to shrink too fast to cause shrinkage cavity to cause low sintering density, and the manufactured nonmetal heat conductor has high reject ratio, so that the temperature rise rate is within 1-5 ℃/min, the manufactured nonmetal heat conductor is ensured to have high mechanical strength, namely the nonmetal heat conductor is ensured to have high mechanical strength.

Several specific examples of the method of fabricating a non-metallic heat spreader device are set forth in detail below: