CN114058180A

CN114058180A - PI heat-conducting and insulating composite material and preparation method and application thereof

Info

Publication number: CN114058180A
Application number: CN202111642704.5A
Authority: CN
Inventors: 周园淇; 张君宝
Original assignee: Suzhou Aileg New Material Co ltd
Current assignee: Suzhou Aileg New Material Co ltd
Priority date: 2021-12-29
Filing date: 2021-12-29
Publication date: 2022-02-18

Abstract

The invention discloses a PI heat-conducting and insulating composite material and a preparation method and application thereof. The PI heat-conducting insulating composite material comprises a polyimide base material layer and heat-conducting silicone rubber layers coated on one side or two sides of the polyimide base material layer. The PI heat-conducting insulating composite material has excellent heat-conducting property and insulating property under the condition of very thin thickness, the heat-conducting coefficient is more than 1w/mk, the insulating strength is more than 4kv/mil, the heat-conducting property and the insulating property can still be kept well under the high-temperature environment, and the product stability is good.

Description

PI heat-conducting and insulating composite material and preparation method and application thereof

Technical Field

The invention relates to the technical field of heat-conducting and insulating materials, in particular to a PI heat-conducting and insulating composite material and a preparation method and application thereof.

Background

Along with the rapid development of the electronic industry, the functions of electronic products become stronger and the electronic products are more and more portable, the size is smaller and smaller, the functions are more and more powerful, the integration level is higher and higher, the size is reduced, and the heat dissipation requirement of electronic components is higher and higher directly.

At present, polymer media are widely applied in the technical field of power electronics, and with the miniaturization development of power electronic equipment, higher and higher requirements are put on the insulating property of the polymer media. Therefore, while the miniaturization of the device is achieved by reducing the size of the insulating structure, the electric field strength borne by the insulating medium is further increased, which leads to an increased possibility of local breakdown and even overall burning of the insulating material. Meanwhile, the polymer medium with high insulating property generally has poor thermal conductivity, so that heat in equipment operation cannot be dissipated, and the material can work at a high temperature for a long time, and the performance and the service life of the insulating material can be seriously influenced by the continuous heating and aging.

In the prior art, PTC thermal sensitive ceramics are often selected in new energy automobiles as a heating mode of an air conditioner, so that a heat conducting and insulating material is needed, the insulating property is met, and meanwhile heat is conveyed to relevant areas such as a passenger compartment and a battery pack to the maximum extent. As the working temperature of the PTC air conditioner of the new energy automobile reaches more than 200 ℃, a high-temperature resistant film is needed as a base material; because the working voltage of the new energy automobile is higher, a film with very good insulating property is needed as a base material; polyimide PI is a common special engineering plastic and is widely applied to the special fields of microelectronics and the like as a structural material and a functional material. However, the single polyimide film has poor thermal conductivity, and cannot meet the comprehensive performance requirements of insulation and high thermal conductivity.

CN102391646B discloses an enhanced high-insulation composite material and a preparation method thereof, wherein the composite material comprises a matrix resin and an additive, the matrix resin is micron-sized polyimide PI, the additive is nano-sized zinc oxide ZnO, and the composite material comprises the following components in percentage by mass: polyimide PI is 90-99%, zinc oxide ZnO is 1-10%; the preparation method of the reinforced high-insulation composite material comprises the following steps: dispersing zinc oxide ZnO, performing surface treatment, pretreating polyimide PI molding powder, and mixing two raw material powders in a liquid phase, and performing rapid stirring and drying treatment, cold press molding and high temperature molding; the composite material prepared by the method has high insulativity and good heat-conducting property. The invention adopts the way that the heat-conducting filler is added into the PI to improve the heat-conducting property of the material, however, the film-forming property of the polymer can be influenced by adding too much heat-conducting filler, and when the content of the additive is 10 wt%, the heat-conducting coefficient is below 0.3W/mK, so the improvement of the heat-conducting property of the PI material by adding the heat-conducting filler is limited.

CN110154418A discloses a method for manufacturing a PI film with good thermal conductivity, which comprises the steps of mixing and reacting a required filler with a solvent, diamine and dianhydride by adopting an in-situ polymerization method to prepare polyamic acid with the required filler; then, uniformly coating polyamic acid on a plane plate by using a film coating machine, and then putting the plane plate into a high-temperature oven for imidization to generate the required polyimide; finally, taking out the product to peel off the polyimide film on the plate to obtain the required polyimide layer; then putting the polyimide layer in the middle, respectively laying an epoxy resin layer on the upper and lower sides of the polyimide layer, and rolling and combining the epoxy resin layers by using a rolling machine to obtain the required material. The polyimide composite film prepared by the method has the characteristics of insulation and good heat conduction, and can be applied to multiple fields of LED illumination and the like. However, the thermal conductivity of the PI material doped with boron nitride is only improved to 0.015W/mK, and the improvement of the thermal conductivity of the PI material is limited.

Therefore, it is necessary to develop a material with high thermal conductivity and better surface flatness to meet the development requirement of the composite thermal conductive insulating material.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a PI heat-conducting insulating composite material and a preparation method and application thereof, and the PI heat-conducting insulating composite material has excellent heat-conducting property and insulating property under the condition of very thin thickness, the heat-conducting coefficient is 1-3W/mK, the insulating strength is more than 4kv/mil, and the PI heat-conducting insulating composite material can still keep good heat-conducting property and insulating property under the high-temperature environment, the thermal weight loss is 0.3-0.9%, the product stability is good, the high-temperature resistance is good, and the PI heat-conducting insulating composite material does not deform at the high temperature of 200 ℃.

One of the objectives of the present invention is to provide a PI thermal conductive insulation composite material, and to achieve the objective, the present invention adopts the following technical scheme:

the PI heat-conducting insulating composite material comprises a polyimide base material layer and a heat-conducting silicone rubber layer coated on one side or two sides of the polyimide base material layer.

According to the PI heat-conducting insulating composite material, the heat-conducting silicone rubber layers are compounded on one side or two sides of the polyimide substrate, so that the composite material has excellent heat-conducting property and insulating property under the condition of very thin thickness, can still keep good heat conductivity and insulating property in a high-temperature environment, and is good in product stability.

The thickness of the polyimide substrate layer is 5 to 100. mu.m, for example, 5. mu.m, 10. mu.m, 15. mu.m, 17. mu.m, 20. mu.m, 22.5. mu.m, 25. mu.m, 28. mu.m, 30. mu.m, 32. mu.m, 34. mu.m, 36.5. mu.m, 37.5. mu.m, 38. mu.m, 40. mu.m, 43. mu.m, 45. mu.m, 48. mu.m, 50. mu.m, 55. mu.m, 60. mu.m, 65. mu.m, 70. mu.m, 80. mu.m, 90. mu.m, 95. mu.m, or 100. mu.m.

And the insulation strength of the polyimide substrate layer is more than 4 kv/mil.

As a preferred scheme, the polyimide substrate layer is a common polyimide film or a heat-conducting polyimide film; the purchase manufacturer of the polyimide substrate layer is not particularly limited; the heat-conducting polyimide film is added with the heat-conducting filler, so that the polyimide film has better heat-conducting property, and can be better used in an environment with higher heat dissipation requirement.

The thickness of the heat-conductive silicone rubber layer is 1-400 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 22.5 μm, 25 μm, 28 μm, 30 μm, 33 μm, 35 μm, 38 μm, 40 μm, 45 μm, 48 μm, 50 μm, 55 μm, 58 μm, 60 μm, 65 μm, 70 μm, 75 μm, 78 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 280 μm, 300 μm, 290 μm, 340 μm, 330 μm, 310 μm, 340 μm, 310 μm, 320 μm, 220 μm, 320 μm, 300 μm, 320 μm, 300 μm, 320 μm, 300 μm, 320 μm, 300 μm, 9 μm, 300 μm, 9 μm, and the like, 380 μm, 390 μm or 400 μm. For example, in one embodiment, the thickness of the heat-conducting silicone rubber layer is 1-100 μm, and the obtained heat-conducting material is thinner, so that the heat-conducting silicone rubber layer can be used in products with strict requirements on the thickness of the heat-conducting material, such as chips; in another embodiment, the thickness of the heat-conducting silicone rubber layer is 100-400 μm, and the obtained heat-conducting material can be used in products with relatively large space and no special requirement on the thickness of the heat-conducting material.

The heat-conducting silicone rubber can be manufactured by self or purchased, and preferably, the heat-conducting silicone rubber of the heat-conducting silicone rubber layer is single-component or double-component. The first component and the second component both comprise at least one of heat-conducting filler, solvent and catalyst.

Preferably, the heat-conducting silicone rubber is two-component and comprises a first component and a second component in a mass ratio of 1 (0.7-1.4), and the first component and the second component are calculated by mass percentage,

the first component comprises the following components:

the mass percentage of the vinyl silicone is 3 to 40%, for example, 3%, 4%, 5%, 10%, 15%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or the like.

The mass percentage of the first thermally conductive filler is 60 to 95%, for example, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95%.

The platinum catalyst is used in an amount of 50 to 150ppm, for example, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm, 110ppm, 120ppm, 130ppm, 140ppm, 150ppm, or the like.

The first solvent makes up the balance to 100%.

The second component comprises the following components:

the hydrogenpolysiloxane is 3 to 40% by mass, for example, 3%, 4%, 5%, 10%, 15%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or the like.

The second thermally conductive filler is 60 to 95% by mass, for example, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95% by mass.

The second solvent makes up the balance to 100%.

The first heat-conducting filler and the second heat-conducting filler are independently selected from any one of aluminum oxide, aluminum nitride, silicon nitride, aluminum hydroxide, zinc oxide, boron nitride and carbon fiber or a mixture of at least two of the aluminum oxide, the aluminum nitride, the silicon nitride, the aluminum hydroxide, the zinc oxide, the boron nitride and the carbon fiber.

Preferably, the first and second thermally conductive fillers are independently selected from alumina and/or aluminum nitride; the specific type of the alumina is not particularly limited in this application, and various types of alumina known to those skilled in the art may be selected, including but not limited to alpha-alumina, gamma-alumina, alumina nanowires, and the like. For example, XFI09 α -alumina from Jiangsu Xiancheng nanomaterial science and technology Limited may be selected.

The heat conducting property of the composite heat conducting insulating film can be obviously improved by regulating and controlling the type and the proportion of the heat conducting filler; in addition, the thickness tolerance and the surface flatness of the composite heat-conducting insulating film can be better improved by adopting the heat-conducting filler with the components in the mixture preparation and the coating post-curing forming process of the preparation raw materials of the composite heat-conducting insulating film.

The first solvent and the second solvent are independently selected from alkane solvent oil or aromatic hydrocarbon solvent.

Preferably, the solvent oil is sold under the product name EXXSOL TM DSP 80/100 fluid, available from the manufacturer as Exxon Mobil; in another preferred embodiment, the aromatic hydrocarbon solvent is toluene.

The specific type and selection of the vinyl polysiloxane and the hydrogenpolysiloxane are not particularly limited in this application, and various types of vinyl-containing polysiloxane and hydrogenpolysiloxane known to those skilled in the art can be selected.

Preferably, the vinyl polysiloxane has a vinyl content of 4 to 6 wt%, such as 4 wt%, 5 wt%, or 6 wt%, etc., preferably 5 wt%; the viscosity was 2000 cps.

Preferably, the hydrogenpolysiloxane in the invention refers to polysiloxane rubber which contains a hydrogen-terminated structure in a molecular structure and can be crosslinked to form a film under the action of catalysts such as metal salts and noble metals; preferably, the hydrogen content of the hydrogenpolysiloxane is 4-6 wt%, such as 4 wt%, 5 wt%, or 6 wt%, etc., preferably 5%; the viscosity is 500-1500cps, for example, 500cps, 600cps, 700cps, 800cps, 900cps, 1000cps, 1100cps, 1200cps, 1300cps, 1400cps, 1500cps, preferably 1000 cps.

The preparation method of the heat-conducting silicone rubber comprises the following steps: uniformly mixing all the components of the first component to obtain a first mixture; uniformly mixing all the components of the second component to obtain a second mixture; the first component and the second component are uniformly mixed according to the mass ratio of 1 (0.7-1.4), for example, the ratio is 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3 or 1:1.4, and the like, so as to obtain the heat-conducting silicone rubber.

The second purpose of the present invention is to provide a preparation method of the PI thermal conductive and insulating composite material, the preparation method comprising: and compounding the heat-conducting silicone rubber layer on one side or two sides of the polyimide substrate layer through a coating process or a calendaring extrusion process to obtain the PI heat-conducting insulating composite material.

The coating mode of the coating process comprises one of dip coating, spray coating, blade coating, slit coating and brush coating. Preferably, the coating method is knife coating, and more preferably, the coating method is comma knife coating (including slit coating).

The calendering and extruding mode comprises a calendering and extruding process, and the calendering and extruding mode is a mode commonly used in the field.

The coating process or the calendering and extruding process also comprises the step of carrying out corona and dust sticking treatment on the polyimide substrate.

The invention also aims to provide application of the PI heat-conducting and insulating composite material, and the PI heat-conducting and insulating composite material is used for preparing a PTC heater, a solar inverter, an IGBT power chip, a 5G base station and a mobile phone of a new energy automobile air conditioner.

Preferably, the PTC heater is a PTC ceramic heater, and the ceramic PTC ceramic heater is formed by bonding more than 1 PTC heat-sensitive ceramic sheets together through high-temperature resistant resin and aluminum heat dissipation sheets. The PI composite heat-conducting insulating material coats the PTC heater thermosensitive ceramic sheet, and the PTC heater thermosensitive ceramic sheet is coated on the PTC thermosensitive ceramic heating sheet of the new energy automobile, so that heat is conveyed to relevant areas such as a passenger compartment and a battery to the maximum extent, heat loss is reduced, and the heat dissipation and insulating performance of the PTC heater are realized.

Compared with the prior art, the invention has the beneficial effects that:

(1) the PI heat-conducting insulating composite material has excellent heat-conducting property, the heat-conducting coefficient is more than 1W/mK, the heat-conducting coefficient is 1-3W/mK, the insulating strength is more than 4kv/mil, the PI heat-conducting insulating composite material can still keep good heat-conducting property and insulating property in a high-temperature environment, the product stability is good, the high-temperature resistance is good, and the PI heat-conducting insulating composite material does not deform at the high temperature of 200 ℃.

(2) According to the PI heat-conducting insulating composite material, the used heat-conducting silicone rubber has good leveling property, can be prepared by coating, calendering and extruding and other processes, and is beneficial to control of thickness tolerance, surface flatness and the like of an insulating film; and the high-temperature heat-conducting silicone rubber is free from release of small molecules in the curing and using processes, is more environment-friendly and safer, and reduces pollution to devices.

(3) The PI heat-conducting insulating composite material can be prepared into a single-sided or double-sided structure, and has a large thickness range and a wide application scene of products.

(4) The PI heat-conducting insulating composite material can be widely used for preparing a PTC heater of a new energy automobile air conditioner, a solar inverter, an IGBT power chip, a 5G base station and a mobile phone, when the PI heat-conducting insulating composite material is wrapped on a PTC heat-sensitive ceramic heating sheet of the new energy automobile, heat can be conveyed to a passenger compartment, a battery and other related areas to the maximum extent, and heat loss is reduced.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments.

Unless otherwise specified, various starting materials of the present invention are commercially available or prepared according to conventional methods in the art.

Example 1

The embodiment provides a PI composite heat-conducting insulating material which comprises a polyimide substrate layer and a heat-conducting silicone rubber layer compounded on one side of the polyimide substrate layer.

The preparation raw materials of the heat-conducting silicone rubber layer comprise a first component and a second component, wherein the mass ratio of the first component to the second component is 1:1. The first component comprises 15 percent of vinyl siloxane polymer, 80 percent of alumina, 100ppm of platinum catalyst and toluene to make up the balance to 100 percent; the second component comprised 15% hydrosiloxane polymer, 80% alumina, toluene make up the balance to 100%. The vinyl siloxane polymer has a vinyl content of 5 wt% and a viscosity of 2000 cps; the hydrogen-containing silicone polymer has a hydrogen content of 5 wt% and a viscosity of 1000 cps.

The alumina is XFI09 alpha-alumina;

the preparation method of the heat-conducting silicone rubber comprises the following steps: uniformly mixing all the components of the first component to obtain a first mixture; uniformly mixing all the components of the second component to obtain a second mixture; and uniformly mixing the first mixture and the second mixture to obtain the heat-conducting silicone rubber.

The heat-conducting silicone rubber layer is formed by compounding heat-conducting silicone rubber on a polyimide substrate layer in a coating mode; the coating mode is comma scraper coating; .

The base material is a polyimide film, the MT/MT of DuPont is selected, the thickness is 25 micrometers, and the thickness of the cured heat-conducting silicone rubber layer is 245 micrometers.

Example 2

The embodiment provides a PI composite heat-conducting insulating material, which comprises a polyimide substrate layer and heat-conducting silicone rubber layers compounded on two sides of the polyimide substrate layer.

The preparation raw materials of the heat-conducting silicone rubber layer comprise a first component and a second component, wherein the mass ratio of the first component to the second component is 1:1. The first component comprises 15 percent of vinyl siloxane polymer, 80 percent of aluminum hydroxide, 100ppm of platinum catalyst and toluene to make up the balance to 100 percent; the second component comprised 15% hydrosiloxane polymer, 80% aluminum hydroxide, toluene make up the balance to 100%. The vinyl siloxane polymer has a vinyl content of 5 wt% and a viscosity of 2000 cps; the hydrogen-containing silicone polymer has a hydrogen content of 5 wt% and a viscosity of 1000 cps.

The heat-conducting silicone rubber layer is formed by compounding heat-conducting silicone rubber on a polyimide substrate layer in a coating mode; the coating mode is comma scraper coating;

the base material is a polyimide film, the thickness of MT/MT of DuPont is 50 microns, and the thickness of the cured heat-conducting silicone rubber layer is 25 microns.

Example 3

The embodiment provides a PI composite heat-conducting insulating material, which comprises a polyimide substrate layer and heat-conducting silicone rubber layers compounded on two sides of the polyimide substrate layer;

the preparation raw materials of the heat-conducting silicone rubber layer comprise a first component and a second component, wherein the mass ratio of the first component to the second component is 1:1. The first component comprises, in mass percent, 15% vinyl siloxane polymer, 80% aluminum hydroxide, 100ppm platinum catalyst, EXXSOL TM DSP 80/100 fluid (from the manufacturer Exxon Mobil) make up to 100%; the second component comprised 15% hydrosiloxane polymer, 80% aluminum hydroxide, EXXSOL (TM) DSP 80/100 fluid (from Exxon Mobil, Inc.) make up the balance to 100%. The vinyl siloxane polymer has a vinyl content of 5 wt% and a viscosity of 2000 cps; the hydrogen-containing silicone polymer has a hydrogen content of 5 wt% and a viscosity of 1000 cps.

The heat-conducting silicone rubber layer is formed by compounding heat-conducting silicone rubber on a polyimide substrate layer in a coating mode; the coating mode is comma scraper coating; the base material is polyimide film, which is MT/MT from DuPont and has thickness of 25 microns, and the cured 100MT double-sided heat conducting silicone rubber layers have thickness of 100 microns and 150 microns.

Example 4

The heat-conducting silicone rubber layer is formed by compounding heat-conducting silicone rubber on a polyimide substrate layer through calendering/extrusion; calendering/extrusion is calendering extrusion.

The base material is a polyimide film, the thickness of the base material is 25 micrometers by selecting DuPont MT/MT, and the thickness of the cured 100MT heat-conducting silicone rubber layer is 300 micrometers.

Example 5

This example is different from example 1 in that the mass ratio of the first component to the second component is 1:0.7, and the others are the same as those of example 1.

Example 6

This example differs from example 1 in that the mass ratio of the first component to the second component is 1:1.4, and the rest is the same as example 2.

Example 7

This example differs from example 1 in that the vinyl polysiloxane was used in an amount of 50%, the other being the same as in example 1.

Example 8

This example differs from example 1 in that the hydrogenpolysiloxane was used in an amount of 50%, and the rest was the same as in example 1.

Example 9

This example is different from example 1 in that the vinyl group content of the vinyl polysiloxane was 2%, and the rest was the same as example 1.

Example 10

This example is different from example 1 in that the vinyl group content of the vinyl polysiloxane was 8%, and the rest was the same as example 1.

Example 11

This example is different from example 1 in that the hydrogen content of the hydrogenpolysiloxane was 2%, and the rest was the same as example 1.

Example 12

This example is different from example 1 in that the hydrogen content of the hydrogenpolysiloxane was 8%, and the rest was the same as example 1.

Comparative example 1

The PI heat-conducting and insulating composite material of the comparative example is a material with ZnO added in conventional matrix resin PI, and specifically comprises the following components: the polyimide PI is 95%, the zinc oxide ZnO is 5%, and the preparation method comprises the following steps:

dispersing and surface treating zinc oxide (ZnO), weighing zinc oxide (ZnO) powder with the diameter of 80nm and the preset mass, adding the zinc oxide (ZnO) powder into alcohol with the volume 10 times that of the zinc oxide (ZnO) powder, then placing suspension of the zinc oxide (ZnO) powder and the alcohol into an ultrasonic vibration instrument for dispersing for 60min, adding a silane coupling agent KH550 accounting for 5% of the mass of the zinc oxide (ZnO) into the suspension in the ultrasonic vibration process, then placing the suspension added with the coupling agent into an oven for drying for 36h at the drying temperature of 80 ℃, and drying the alcohol to obtain a zinc oxide (ZnO) raw material after dispersion and surface treatment; pretreating polyimide PI molding powder, weighing polyimide PI molding powder with the powder diameter of 10 mu m and the preset mass, and then placing the polyimide PI molding powder in an oven for drying for 24 hours at the drying temperature of 70 ℃ to obtain a pretreated polyimide PI raw material;

weighing the obtained pretreated polyimide PI raw material and the dispersed and surface-treated zinc oxide ZnO raw material, placing the raw materials in a beaker to form a mixture, enabling the content of zinc oxide to be 10% of the total mass of the mixture, adding alcohol with the volume 4 times that of the mixture into the beaker to form a suspension, quickly stirring for 60min by using a stirrer to obtain a uniformly dispersed suspension, and then placing the suspension into a drying oven to dry at the drying temperature of 100 ℃ for 48 h;

placing the dried uniformly dispersed suspension into a grinding tool for cold press molding, wherein the molding pressure is 12MPa, the duration is 15s, and repeatedly cold pressing for 3 times to obtain a sample after cold press molding;

and (3) placing the sample subjected to cold press molding in a molding press for high-temperature molding, wherein the molding pressure is 12MPa, the molding temperature is sectional heating and heat preservation, and the specific process comprises the steps of heating to 260 ℃ from room temperature for 30min, preserving heat for 30min, then heating to 340 ℃ for 30min, preserving heat for 30min, and then naturally cooling along with a furnace body to obtain the PI heat-conducting and insulating composite material.

The heat conductive and insulating composite materials prepared in examples 1 to 12 and comparative example 1 were subjected to performance tests, and the test results are shown in table 1.

Wherein, the thickness tolerance test is carried out according to the standard of GB/T7125-2014 test method for the thickness of the adhesive tape, and the thickness deviation is tested after the thickness of 10 prepared samples in different batches is tested; the thermal conductivity was measured according to the standard of ASTM D5470; the insulation strength was measured according to ASTM D149, and the thermogravimetric analysis was carried out using a thermogravimetric analyzer TGA-601.

TABLE 1

As can be seen from Table 1, compared with the material prepared by adding ZnO filler into the conventional matrix resin of comparative example 1, the PI heat-conducting insulating composite material has excellent heat-conducting property and insulating property under the condition of very thin thickness, the heat-conducting coefficient is 1-3W/mK, the insulating strength is more than 4kv/mil, and the PI heat-conducting insulating composite material can still keep good heat-conducting property and insulating property under the high-temperature environment, the thermal weight loss is 0.3-0.9%, the product stability is good, the high-temperature resistance is good, and the PI heat-conducting insulating composite material does not deform at the high temperature of 200 ℃.

Example 7 the use of vinyl polysiloxane in too much amount results in a lower thermal conductivity and a higher weight loss.

Example 8 the hydrogen-containing polysiloxane was used in an excessive amount to accelerate the reaction and to harden the surface.

Example 9 vinyl polysiloxane has too low a vinyl group content to be easily molded.

Example 10 vinyl polysiloxane has too much vinyl content, the thermal conductivity becomes small, and the thermal weight loss becomes large.

Example 11 the hydrogen content of the hydrogenpolysiloxane was too low, the reaction was incomplete and the weight loss on heating was large.

Example 12 the hydrogen content of the hydrogenpolysiloxane was too high, the reaction rate was accelerated, and the surface hardness was high, which was not favorable for use.

The comparison between example 1 and comparative example 1 shows that the material with ZnO added to the conventional matrix resin PI has a significantly lower thermal conductivity and a greater weight loss due to heat.

The present invention is illustrated by the above-mentioned examples, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, i.e. it is not meant to imply that the present invention must rely on the above-mentioned detailed process equipment and process flow to be practiced. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. The PI heat-conducting insulating composite material is characterized by comprising a polyimide base material layer and heat-conducting silicone rubber layers coated on one side or two sides of the polyimide base material layer.

2. The PI thermal insulation composite of claim 1, wherein the polyimide substrate layer has a thickness of 5-100 μ ι η;

3. The PI thermally conductive insulating composite of claim 1 or 2 wherein the thermally conductive silicone rubber layer has a thickness of 1-400 μm.

4. The PI thermal insulation composite of claim 1 wherein the thermally conductive silicone rubber of the thermally conductive silicone rubber layer is one or two component.

5. The PI heat-conducting and insulating composite material as claimed in claim 1, wherein the heat-conducting silicone rubber is a two-component material comprising a first component and a second component in a mass ratio of 1 (0.7-1.4) by mass percentage,

the first component comprises the following components:

the second component comprises the following components:

hydrogen-containing polysiloxane 3-40%

60 to 95 percent of second heat-conducting filler

The second solvent makes up the balance to 100%.

6. The PI thermal insulation composite as claimed in claim 5, wherein the vinyl polysiloxane has a vinyl content of 4-6 wt%, a viscosity of 1000-3000 cps;

the hydrogenpolysiloxane contains a hydrogen-terminated structure, the hydrogen content of the hydrogenpolysiloxane is 4-6 wt%, and the viscosity of the hydrogenpolysiloxane is 500-1500 cps;

the first heat-conducting filler and the second heat-conducting filler are independently selected from any one of or a mixture of at least two of aluminum oxide, aluminum nitride, silicon nitride, aluminum hydroxide, zinc oxide, boron nitride and carbon fiber;

7. The preparation method of the PI thermal insulation composite material as claimed in any one of claims 1 to 6, wherein the preparation method comprises the following steps: and compounding the heat-conducting silicone rubber layer on one side or two sides of the polyimide substrate layer through a coating process or a calendaring extrusion process to obtain the PI heat-conducting insulating composite material.

8. The preparation method according to claim 7, wherein the coating manner of the coating process comprises one of dip coating, spray coating, blade coating, slit coating and brush coating.

9. The method according to claim 7, wherein the coating process or the calendering and extruding process is preceded by a step of performing corona and dust treatment on the polyimide substrate.

10. The application of the PI heat-conducting and insulating composite material as claimed in any one of claims 1 to 6, wherein the PI heat-conducting and insulating composite material is used for preparing a PTC heater of a new energy automobile air conditioner, a solar inverter, an IGBT power chip, a 5G base station and a mobile phone.