A high-sensitivity temperature detection device and preparation method thereof

Abstract

The invention specifically relates to a high-sensitivity temperature detection device and a preparation method thereof. The temperature detection device comprises: a temperature measuring component, a heat-conducting insulating block, an electromagnetic shielding layer and a protective packaging layer; the heat-conducting insulating block is a heat-conducting composite material, which is prepared by pressing diphenylmethane bismaleimide resin and a modified mixed filler; the mass percentage ratio of the diphenylmethane bismaleimide resin to the modified mixed filler is 100:(300-400); the modified mixed filler is boron nitride and silicon nitride modified by acid anhydride grafting, and aluminum nitride modified by surface modification; the particle size of the boron nitride is 20-50 μm, the particle size of the silicon nitride is 2-10 μm, and the particle size of the aluminum nitride is 20-50 nm; the mass percentages of the boron nitride, the silicon nitride and the aluminum nitride are 1:(1.1-1.3):(0.8-0.9). The heat-conductive insulating block of the present invention has excellent thermal conductivity, insulation and adhesion. Combined with the layer-by-layer coated structure of the temperature detection device, the temperature detection device has extremely high sensitivity and can be safely used in strong electric and magnetic environments.

Description

Technical Field

[0001] The invention belongs to the technical field of heat-conducting insulating materials and temperature sensors, and in particular relates to a high-sensitivity temperature detection device and a preparation method thereof. Background Art

[0002] The progress of my country's industrial modernization and the continuous high-speed growth of the electronic information industry have driven the rapid rise of the sensor market. Temperature sensors, as an important type of sensor, account for more than 40% of the total demand for sensors. A temperature sensor (temperature transducer) refers to a sensor that can sense temperature and convert it into a usable output signal. Temperature sensors are the core part of temperature measuring instruments and come in a wide variety. However, in a strong electric and magnetic environment, metal sensors cannot directly contact the surface of the equipment when in use, resulting in reduced sensitivity of the sensor and increased working hazards. Therefore, in order to meet the use of metal sensors in strong electric and magnetic environments, it is necessary to design a plastic thermal conductive block to provide metal sensors with an insulating material with extremely high insulation strength, certain plasticity, and extremely fast thermal conductivity, and to provide conventional industrial-grade sensors with the possibility of working in a strong electric and magnetic environment of the power grid, thereby protecting the sensors.

[0003] At present, thermal conductive blocks are often made of thermal conductive ceramic blocks or thermal conductive composite materials. Patent CN103557959A discloses a fiber grating temperature sensor probe, including: a fiber grating packaging sleeve, a fiber grating and a thermal conductive protective sleeve; the grating area of ​​the fiber grating is located inside the fiber grating packaging sleeve for temperature measurement, one end of which is fixed and the other end is suspended; the two ends of the thermal conductive protective sleeve are fixed with clamping ends for encapsulating the fiber grating packaging sleeve, and the tail optical fiber of the fiber grating passes through the clamping end. The fiber grating packaging sleeve is made of copper material with good thermal conductivity, and the thermal conductive protective sleeve is made of ceramic material with good insulation and strong anti-electromagnetic interference ability; the clamping end is made of high temperature resistant insulating material. The fiber grating temperature sensor probe of this invention has a small size, fast response speed, and a simple packaging structure. It can eliminate the influence of external stress on the temperature measurement of the sensor, and can shield the influence of electromagnetic interference. However, the thermal conductive ceramic block is difficult to process, brittle, and not easy to bond with the probe.

[0004] Patent CN108801489A discloses a temperature sensor, including a temperature sensor probe and a data acquisition element. The temperature sensor probe includes a temperature-sensitive carbon nanomaterial layer, a heat-conducting matrix and a packaging shell, wherein the temperature-sensitive carbon nanomaterial layer is arranged on the heat-conducting matrix and is packaged inside the packaging shell. There is a heat-insulating layer between the packaging shell and the temperature-sensitive carbon nanomaterial. At least a portion of the heat-conducting matrix is ​​exposed outside the packaging shell. At least two portions of the temperature-sensitive carbon nanomaterial layer are used as electrodes and are electrically connected to the circuit acquisition element respectively. The invention also provides a preparation method thereof: modifying the temperature-sensitive carbon nanomaterial layer on the surface of the heat-conducting matrix, then electrically connecting at least two portions of the temperature-sensitive carbon nanomaterial layer to the circuit acquisition element respectively, then packaging the temperature-sensitive carbon nanomaterial layer inside the packaging shell, and filling a heat-insulating layer between the temperature-sensitive carbon nanomaterial layer and the packaging shell, and at least a portion of the heat-conducting matrix is ​​exposed outside the packaging shell to form a temperature sensor. However, the thermal conductivity of the heat-conducting composite material used in the invention is low, the detection sensitivity of the sensor is affected, and the safety of use cannot be guaranteed when applied in a strong electric and magnetic environment.

[0005] Therefore, how to obtain a thermally conductive composite material for a temperature detection device with high thermal conductivity, good insulation and excellent adhesion, which can improve the sensitivity of the temperature detection device and can be safely used in strong electric and magnetic environments, has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0006] In view of the defects existing in the above-mentioned prior art, the purpose of the present invention is to provide a temperature detection device of a thermally conductive insulating block with high thermal conductivity, insulation and excellent adhesion. The temperature detection device has high sensitivity and can be used in strong electric and magnetic environments.

[0007] Specifically, the present invention provides a high-sensitivity temperature detection device, which includes: a temperature measurement component, a heat-conducting insulating block, an electromagnetic shielding layer, and a protective packaging layer;

[0008] The thermally conductive insulating block is a thermally conductive composite material, and the thermally conductive composite material is prepared by compression molding of diphenylmethane bismaleimide resin and modified mixed filler;

[0009] The mass percentage ratio of the diphenylmethane bismaleimide resin to the modified mixed filler is 100:(300-400);

[0010] The modified mixed filler is boron nitride and silicon nitride modified by acid anhydride grafting, and aluminum nitride modified by surface modification;

[0011] The particle size of the boron nitride is 20-50 μm, the particle size of the silicon nitride is 2-10 μm, and the particle size of the aluminum nitride is 20-50 nm;

[0012] The mass percentage of the boron nitride, silicon nitride and aluminum nitride is 1:(1.1-1.3):(0.8-0.9).

[0013] The temperature sensor of the present invention has extremely high sensitivity, and its temperature sensor measurement standard is 0.1°C level, and the test range is -50-150°C.

[0014] The temperature detection device of the present invention has a clear structure and adopts a layered structure that is coated in sequence. The temperature measuring component is coated on the innermost layer of the entire temperature detection device, and the thermal conductive joint of the thermal conductive insulating block is bonded. Insulating resin is injected by pouring, so that the temperature measuring component and part of the thermal conductive joint are coated with the insulating resin, and then the electromagnetic shielding layer is wrapped, and then the protective packaging layer is cast. After curing, a temperature detection device with clear layers is obtained.

[0015] The heat-conducting insulating block of the present invention is a heat-conducting composite material with a high filling amount of filler powder to form an efficient heat-conducting network and improve the thermal conductivity of the material. At the same time, by using micron-level fillers and nano-level fillers of different particle sizes, the nano-level fillers fill the gaps between the micron-level fillers, reducing the contact area between the fillers and the matrix, and more easily forming a heat-conducting network structure. The thermal conductivity of the heat-conducting composite material used in the present invention is ≥25W·m -1 ·K -1 , volume resistivity ≥1×10 15 Ω·cm, with excellent plasticity and thermal insulation properties.

[0016] The boron nitride of the present invention is micron-sized flaky hexagonal boron nitride, which is a single crystal structure hexagonal phase boron nitride material with a two-dimensional flaky nanomorphology. Its two-dimensional nanomorphology gives it very special and excellent physical and chemical properties, and has very good thermal conductivity, electrical insulation, chemical corrosion resistance and oxidation resistance. Flaky hexagonal boron nitride is also an excellent thermal conductive filler, which can improve the thermal conductivity of the material and reduce its dielectric loss. Silicon nitride is an excellent filler and reinforcement for insulating packaging resins in the electronic components industry, and is also an excellent insulating thermal conductive filler for thermal interface materials, which can improve the thermal conductivity of the material. Aluminum nitride has high thermal conductivity, low dielectric constant and dielectric loss, and is considered to be the preferred material for new generation electronic packaging and other devices, which can significantly improve the strength, toughness, modulus, thermal conductivity and reliability of the product.

[0017] Furthermore, the temperature measuring component includes a temperature sensor, a temperature measuring circuit board, a power supply element and wires. The temperature measuring component is coated with an insulating resin, and the insulating resin is one or more of epoxy resin, phenolic resin, polyester resin, silicone resin and polyimide. The power supply element is an energy system such as a battery and a capacitor. The wires connect the temperature measuring circuit board through each layer of the temperature detection device and are connected to the PLC and other equipment.

[0018] Furthermore, the thermally conductive insulating block includes a thermally conductive joint, which is connected to the temperature sensor. The thermally conductive insulating block also includes a thermally conductive block, the inner side of which is connected to the temperature sensor, and the outer side of which is in contact with the interface to be measured or connected to the thermally conductive block, and the interface to be measured is contacted by the thermally conductive block. The thermally conductive insulating block includes one or more detachable thermally conductive blocks, and the number of thermally conductive blocks is adjusted according to the voltage strength and electromagnetic strength of the interface to be measured.

[0019] Furthermore, the specific method of anhydride grafting modification is: add unmodified boron nitride and silicon nitride to an organic solvent, add 4-7% isocyanate by mass, stir at room temperature for 20-24 hours, add anhydride solution, react at 75-100°C for 5-7 hours, vacuumize and repeatedly wash, and dry at 50-70°C to obtain boron nitride and silicon nitride modified by anhydride grafting.

[0020] Furthermore, the molar percentage of the acid anhydride to the isocyanate is (1-1.2):1, the acid anhydride is selected from at least one of unsaturated acid anhydride, maleic anhydride, and methyl sodium Dicke acid anhydride, and the isocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate; and the organic solvent is at least one of toluene, xylene, and butanone.

[0021] The compatibility of boron nitride and silicon nitride modified by anhydride grafting isocyanate with diphenylmethane bismaleimide resin is significantly enhanced, which improves the thermal conductivity of the composite material. In addition, the use of modified fillers can increase the tensile strength and elongation at break of the composite material.

[0022] Furthermore, the surface modification method of aluminum nitride is as follows: drying the aluminum nitride in a vacuum oven at 140-160°C for 20-24h, then dispersing the dried aluminum nitride and 3-aminopropyltrimethoxysilane in an ethanol aqueous solution with a mass fraction of 93-95%, and ultrasonically treating for 10-25min; after ultrasonic treatment, magnetically stirring at 75-85°C for 1.5-3h, repeatedly washing with anhydrous ethanol, and drying at 100-120°C for 10-12h to obtain surface-modified aluminum nitride.

[0023] Furthermore, the mass percentage ratio of aluminum nitride to 3-aminopropyltrimethoxysilane is 1:(0.03-0.10).

[0024] The interaction between aluminum nitride modified by 3-aminopropyltrimethoxysilane and the polymer matrix is ​​enhanced, and the interfacial thermal resistance between the aluminum nitride and the matrix is ​​reduced, so that the thermal conductivity of the thermally conductive composite material is significantly increased, thereby improving the thermal conductivity of the material.

[0025] Furthermore, the electromagnetic shielding layer comprises a metal dot matrix structure layer and a polyimide base film layer, the metal is selected from any one of copper, aluminum, silver and gold, the thickness of the electromagnetic shielding layer is 1-100 nm, and the volume resistivity is ≥1×10 12 Ω·cm, with high electromagnetic shielding, avoiding external electromagnetic interference to the temperature sensor and improving the sensitivity of the temperature detection device.

[0026] On the other hand, a method for preparing a temperature detection device is provided, wherein the temperature detection device is prepared by casting, specifically:

[0027] S1: preparing thermally conductive insulating blocks;

[0028] S2: Bond the temperature measuring device to the heat-conducting insulating block by using thermal grease;

[0029] S3: pouring insulating resin and wrapping the metal shielding layer after curing;

[0030] S4: pouring a protective encapsulation layer, and preparing the temperature detection device after curing.

[0031] The protective encapsulation layer is an epoxy resin layer, preferably the SG-001 material of Zhejiang Senfu Electric Technology Co., Ltd. The thickness of this layer is 1-5 cm, which can improve the insulation performance of the temperature detection device.

[0032] Further, S1 includes the following steps:

[0033] Step 1: preparing boron nitride and silicon nitride modified by anhydride grafting;

[0034] Step 2: preparing surface-modified aluminum nitride;

[0035] Step 3: Add boron nitride, silicon nitride and aluminum nitride to diphenylmethane bismaleimide resin, then add diisopropylbenzene peroxide and auxiliary materials, and stir evenly;

[0036] Step 4: Prepare the thermally conductive insulating block by compression molding.

[0037] The auxiliary materials are all in powder form, specifically hot melt adhesive, polyamide, thermoplastic polyimide and polyetherimide in a mass percentage ratio of 1: (0.0003-0.0007): (0.05-0.08): (0.02-0.04).

[0038] The thermal conductive composite material prepared by this process has a high filler content in powder and high thermal conductivity; the powders are bonded by polymers, the processing technology is simple, and the thermal conductive composite material has good toughness; the auxiliary materials added can also improve the adhesion between the temperature sensor and the thermal conductive composite material, i.e., the thermal conductive insulating block.

[0039] The present invention has the advantages that:

[0040] 1) The structure of the temperature detection device of the present invention adopts a layered structure that is coated in sequence, and the temperature measuring component is coated at the core position of the entire temperature detection device. The outside is filled and coated with insulating resin, wrapped with an ultra-thin electromagnetic shielding layer, and protected and packaged with materials with excellent heat-resistant and insulating properties, so that the thermal conductivity and insulation properties of the temperature detection device are greatly improved.

[0041] 2) The thermally conductive composite material filler powder used in the thermally conductive insulating block of the present invention has a high filling amount. At the same time, by using micron-level fillers and nano-level fillers with different particle sizes in combination, the nano-level fillers fill the gaps between the micron-level fillers, and it is easier to form a thermally conductive network structure; in addition, the micron-level fillers and nano-level fillers of the present invention are modified in different ways to significantly enhance the compatibility of the fillers with diphenylmethane bismaleimide resin, thereby improving the thermal conductivity of the composite material. In addition, the use of modified fillers can increase the tensile strength and elongation at break of the composite material.

[0042] 3) In the present invention, the temperature sensor of the temperature detection device is connected to a heat-conducting insulating block, and the thermal conductivity of the heat-conducting insulating block is ≥15W·m -1 ·K -1 , can reach 25W·m -1 ·K -1 , the volume resistivity can reach 1×10 15 Ω·cm, has extremely excellent thermal conductivity and insulation properties, improves the sensitivity and measurement accuracy of the temperature sensor, and also enables the temperature detection device of the present invention to be applied to strong electric and magnetic environments such as power grids, ensuring that the temperature detection device still has high sensitivity and safety when used in special environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A top view of the temperature detection device of the present invention is shown.

[0044] Explanation of the reference numerals: 1. Temperature measuring circuit board; 2. Power supply element; 3. Temperature sensor; 4. Thermally conductive insulating block; 41. Temperature measuring probe; 42. Thermally conductive block; 5. Insulating resin; 6. Electromagnetic shielding layer; 61. Polyimide base film layer; 62. Metal dot matrix structure layer; 7. Protective packaging layer. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with embodiments.

[0046] A high-sensitivity temperature detection device, comprising: a temperature measurement component, a heat-conducting insulating block 4, an electromagnetic shielding layer 6 and a protective packaging layer 7;

[0047] The temperature measuring component includes a temperature sensor 3, a temperature measuring circuit board 1, a power supply element 2 and wires. The temperature measuring component is coated with an insulating resin 5. The insulating resin 5 is one or more of epoxy resin, phenolic resin, polyester resin, silicone resin and polyimide. The power supply element 2 is an energy system such as a battery or a capacitor. The wires connect the temperature measuring circuit board 1 through each layer of the temperature detection device and are connected to devices such as PLC.

[0048] The thermally conductive insulating block 4 includes a thermally conductive joint 41 and a thermally conductive block 42. The inner side of the thermally conductive joint 41 is connected to the temperature sensor 3, and the outer side thereof is in contact with the interface to be measured or connected to the thermally conductive block 42. The thermally conductive insulating block 4 includes one or more detachable thermally conductive blocks 42.

[0049] The thermally conductive insulating block 4 is a thermally conductive composite material, which is prepared by pressing diphenylmethane bismaleimide resin and modified mixed filler; the mass percentage ratio of diphenylmethane bismaleimide resin to modified mixed filler is 100:(300-400); the modified mixed filler is boron nitride and silicon nitride modified by acid anhydride grafting, and aluminum nitride modified by surface modification; wherein the particle size of boron nitride is 20-50μm, the particle size of silicon nitride is 2-10μm, and the particle size of aluminum nitride is 20-50nm; the mass percentage of boron nitride, silicon nitride and aluminum nitride is 1:(1.1-1.3):(0.8-0.9).

[0050] The electromagnetic shielding layer 6 comprises a metal dot matrix structure layer 62 and a polyimide base film layer 61, wherein the metal is selected from any one of copper, aluminum, silver and gold, and the thickness of the electromagnetic shielding layer 6 is 1-100 nm. The metal dot matrix structure layer 62 can be located on one side of the polyimide base film layer 61, or on both sides of the polyimide base film layer 61.

[0051] The protective encapsulation layer 7 is an epoxy resin layer, preferably the SG-001 material produced by Zhejiang Senfu Electric Technology Co., Ltd., and the thickness of the layer is 1-5 cm.

[0052] A high-sensitivity temperature detection device is prepared by casting, and the specific preparation method includes the following steps:

[0053] S1: preparing thermally conductive insulating blocks;

[0054] S1.1: Preparation of boron nitride and silicon nitride modified by acid anhydride grafting: Add unmodified boron nitride and silicon nitride to an organic solvent, add 4-7% isocyanate by mass, stir at room temperature for 20-24h, add anhydride solution, react at 75-100℃ for 5-7h, vacuumize and repeatedly wash, and dry at 50-70℃ to obtain boron nitride and silicon nitride modified by acid anhydride grafting; wherein the molar percentage of acid anhydride to isocyanate is (1-1.2):1, the acid anhydride is selected from at least one of unsaturated acid anhydride, maleic anhydride, and methyl sodium Dicke anhydride, and the isocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate; the organic solvent is at least one of toluene, xylene, and butanone;

[0055] S1.2: Preparation of surface-modified aluminum nitride: drying aluminum nitride in a vacuum oven at 140-160°C for 20-24h, and then dispersing aluminum nitride and 3-aminopropyltrimethoxysilane in a mass percentage ratio of 1:(0.03-0.10) in an ethanol aqueous solution with a mass fraction of 93-95%, and ultrasonically treating for 10-25min; after ultrasonic treatment, magnetically stirring at 75-85°C for 1.5-3h, repeatedly washing with anhydrous ethanol, and drying at 100-120°C for 10-12h to obtain surface-modified aluminum nitride;

[0056] S1.3: Add boron nitride, silicon nitride and aluminum nitride to diphenylmethane bismaleimide resin, then add diisopropylbenzene peroxide and auxiliary materials, and stir evenly. The auxiliary materials are hot melt adhesive, polyamide, thermoplastic polyimide and polyetherimide in a mass percentage ratio of 1: (0.0003-0.0007): (0.05-0.08): (0.02-0.04);

[0057] S1.4: Pressing and molding at 200-220°C and 12-15MPa on a press to prepare a thermally conductive insulating block;

[0058] S2: Bond the temperature measuring device to the heat-conducting insulating block by using thermal grease;

[0059] S3: pouring insulating resin and wrapping the metal shielding layer after curing;

[0060] S4: pouring a protective encapsulation layer, and preparing a temperature detection device after curing.

[0061] The pouring process of steps S3 and S4 takes 6-10 hours. After the pouring is completed, it is heated and cured in sections. First, it is cured at 70-90°C for 2-5 hours, then heated to 115-140°C for 3-6 hours, and then naturally cooled to obtain a temperature detection device.

[0062] Example 1

[0063] A high-sensitivity temperature detection device, comprising: a temperature measurement component, a heat-conducting insulating block 4, an electromagnetic shielding layer 6 and a protective packaging layer 7;

[0064] The temperature measuring component includes a temperature sensor 3, a temperature measuring circuit board 1, a power supply element 2 and wires, and the temperature measuring component is coated with silicone resin. The power supply element 2 is a battery, and the wires connect the temperature measuring circuit board 1 through each layer of the temperature detection device and are connected to the PLC.

[0065] The heat-conducting insulating block 4 includes a heat-conducting joint 41 and a heat-conducting block 42 . The inner side of the heat-conducting joint 41 is connected to the temperature sensor 3 , and the outer side thereof is bonded to the interface to be measured through the multi-layer heat-conducting block 42 .

[0066] The thermally conductive insulating block 4 is a thermally conductive composite material, which is prepared by pressing diphenylmethane bismaleimide resin and modified mixed filler; the mass percentage ratio of diphenylmethane bismaleimide resin to modified mixed filler is 100:350; the modified mixed filler is boron nitride and silicon nitride modified by acid anhydride grafting, and aluminum nitride modified by surface modification; wherein the particle size of boron nitride is 40μm, the particle size of silicon nitride is 6μm, and the particle size of aluminum nitride is 35nm; the mass percentage of boron nitride, silicon nitride and aluminum nitride is 1:1.2:0.8.

[0067] The electromagnetic shielding layer 6 comprises a metal dot matrix structure layer 62 and a polyimide base film layer 61 , wherein the metal is selected from any one of copper, aluminum, silver and gold, and the thickness of the electromagnetic shielding layer 6 is 10 nm. The metal dot matrix structure layer 62 is located on one side of the polyimide base film layer 61 .

[0068] The protective packaging layer is SG-001 material from Zhejiang Senfu Electric Technology Co., Ltd., and the thickness of this layer is 3 cm.

[0069] A high-sensitivity temperature detection device is prepared by casting, and the specific preparation method includes the following steps:

[0070] S1: preparing thermally conductive insulating blocks;

[0071] S1.1: Preparation of boron nitride and silicon nitride modified by maleic anhydride grafting: unmodified boron nitride and silicon nitride were added to a toluene solvent, 5% by mass of toluene diisocyanate was added, stirred at room temperature for 22 hours, anhydride solution was added, reacted at 85°C for 6 hours, vacuumed and repeatedly washed, and dried at 60°C to obtain boron nitride and silicon nitride modified by maleic anhydride grafting;

[0072] S1.2: Preparation of surface-modified aluminum nitride: drying aluminum nitride in a vacuum oven at 150°C for 23 hours, and then dispersing aluminum nitride and 3-aminopropyltrimethoxysilane in a mass percentage ratio of 1:0.05 in a 95% ethanol aqueous solution, and ultrasonically treating for 20 minutes; after ultrasonic treatment, magnetic stirring was performed at 80°C for 2 hours, and the mixture was repeatedly washed with anhydrous ethanol, and dried at 110°C for 11 hours to obtain surface-modified aluminum nitride;

[0073] S1.3: Add boron nitride, silicon nitride and aluminum nitride to diphenylmethane bismaleimide resin, and then add diisopropylbenzene peroxide and hot melt adhesive, polyamide, thermoplastic polyimide and polyetherimide in a mass percentage ratio of 1:0.0005:0.05:0.03, and stir evenly;

[0074] S1.4: Pressing and molding at 210°C and 14 MPa in a press to prepare a thermally conductive insulating block;

[0075] S2: Bond the temperature measuring device to the heat-conducting insulating block by using thermal grease;

[0076] S3: pouring insulating resin, and wrapping the metal shielding layer after curing. The pouring process takes 8 hours. After pouring, it is heated and cured in sections, curing at 80°C for 4 hours, and then heating to 130°C for 4 hours.

[0077] S4: pouring a protective encapsulation layer, and preparing a temperature detection device after curing, wherein the pouring process takes 10 hours, and after pouring, it is heated and cured in sections, curing at 75°C for 3 hours, and then heating to 120°C for 5 hours.

[0078] Example 2

[0079] A high-sensitivity temperature detection device, comprising: a temperature measurement component, a heat-conducting insulating block 4, an electromagnetic shielding layer 6 and a protective packaging layer 7;

[0080] The temperature measuring component includes a temperature sensor 3, a temperature measuring circuit board 1, a power supply element 2 and wires, and the temperature measuring component is coated with silicone resin. The power supply element 2 is a battery, and the wires connect the temperature measuring circuit board 1 through each layer of the temperature detection device and are connected to the PLC.

[0081] The heat-conducting insulating block 4 includes a heat-conducting joint 41 and a heat-conducting block 42 . The inner side of the heat-conducting joint 41 is connected to the temperature sensor 3 , and the outer side thereof is bonded to the interface to be measured through the multi-layer heat-conducting block 42 .

[0082] The thermally conductive insulating block is a thermally conductive composite material, which is prepared by pressing diphenylmethane bismaleimide resin and modified mixed filler; the mass percentage ratio of diphenylmethane bismaleimide resin to the modified mixed filler is 100:300; the modified mixed filler is boron nitride and silicon nitride modified by acid anhydride grafting, and aluminum nitride modified by surface modification; among them, the particle size of boron nitride is 20μm, the particle size of silicon nitride is 2μm, and the particle size of aluminum nitride is 20nm; the mass percentages of boron nitride, silicon nitride and aluminum nitride are 1:1.1:0.8.

[0083] The electromagnetic shielding layer 6 comprises a metal dot matrix structure layer 62 and a polyimide base film layer 61 , wherein the metal is selected from any one of copper, aluminum, silver and gold, and the thickness of the electromagnetic shielding layer 6 is 1 nm. The metal dot matrix structure layer 62 is located on one side of the polyimide base film layer 61 .

[0084] The protective packaging layer is made of epoxy resin material, and the thickness of the layer is 1 cm.

[0085] A high-sensitivity temperature detection device is prepared by casting, and the specific preparation method includes the following steps:

[0086] S1: preparing thermally conductive insulating blocks;

[0087] S1.1: Preparation of boron nitride and silicon nitride modified by maleic anhydride grafting: unmodified boron nitride and silicon nitride were added to toluene solvent, 4% by mass of toluene diisocyanate was added, stirred at room temperature for 20 hours, anhydride solution was added, reacted at 75°C for 5 hours, vacuumed and repeatedly washed, and dried at 50°C to obtain boron nitride and silicon nitride modified by maleic anhydride grafting;

[0088] S1.2: Preparation of surface-modified aluminum nitride: drying aluminum nitride in a vacuum oven at 140°C for 20 hours, and then dispersing aluminum nitride and 3-aminopropyltrimethoxysilane in a mass percentage ratio of 1:0.03 in a 93% ethanol aqueous solution, and ultrasonically treating for 10 minutes; after ultrasonic treatment, magnetic stirring was performed at 75°C for 1.5 hours, and the mixture was repeatedly washed with anhydrous ethanol, and dried at 100°C for 10 hours to obtain surface-modified aluminum nitride;

[0089] S1.3: Add boron nitride, silicon nitride and aluminum nitride to diphenylmethane bismaleimide resin, and then add diisopropylbenzene peroxide and hot melt adhesive, polyamide, thermoplastic polyimide and polyetherimide in a mass percentage ratio of 1:0.0003:0.05:0.02, and stir evenly;

[0090] S1.4: Pressing and molding at 210°C and 14 MPa in a press to prepare a thermally conductive insulating block;

[0091] S2: Bond the temperature measuring device to the heat-conducting insulating block by using thermal grease;

[0092] S3: pouring insulating resin, and wrapping the metal shielding layer after curing. The pouring process takes 8 hours. After pouring, it is heated and cured in sections, curing at 80°C for 4 hours, and then heating to 130°C for 4 hours.

[0093] S4: pouring a protective encapsulation layer, and preparing a temperature detection device after curing, wherein the pouring process takes 10 hours, and after pouring, it is heated and cured in sections, curing at 75°C for 3 hours, and then heating to 120°C for 5 hours.

[0094] Example 3

[0095] A high-sensitivity temperature detection device, comprising: a temperature measurement component, a heat-conducting insulating block 4, an electromagnetic shielding layer 6 and a protective packaging layer 7;

[0096] The temperature measuring component includes a temperature sensor 3, a temperature measuring circuit board 1, a power supply element 2 and wires, and the temperature measuring component is coated with silicone resin. The power supply element 2 is a battery, and the wires connect the temperature measuring circuit board 1 through each layer of the temperature detection device and are connected to the PLC.

[0097] The heat-conducting insulating block 4 includes a heat-conducting joint 41 and a heat-conducting block 42 . The inner side of the heat-conducting joint 41 is connected to the temperature sensor 3 , and the outer side thereof is bonded to the interface to be measured through the multi-layer heat-conducting block 42 .

[0098] The thermally conductive insulating block is a thermally conductive composite material, which is prepared by pressing diphenylmethane bismaleimide resin and modified mixed filler; the mass percentage ratio of diphenylmethane bismaleimide resin to the modified mixed filler is 100:400; the modified mixed filler is boron nitride and silicon nitride modified by acid anhydride grafting, and aluminum nitride modified by surface modification; among them, the particle size of boron nitride is 50μm, the particle size of silicon nitride is 10μm, and the particle size of aluminum nitride is 50nm; the mass percentages of boron nitride, silicon nitride and aluminum nitride are 1:1.3:0.8.

[0099] The electromagnetic shielding layer 6 comprises a metal dot matrix structure layer 62 and a polyimide base film layer 61, wherein the metal is selected from any one of copper, aluminum, silver and gold, and the thickness of the electromagnetic shielding layer 6 is 100 nm. The metal dot matrix structure layer 62 may be located on one side of the polyimide base film layer 61.

[0100] The protective packaging layer is SG-001 material produced by Zhejiang Senfu Electric Technology Co., Ltd., and the thickness of this layer is 5 cm.

[0101] A high-sensitivity temperature detection device is prepared by casting, and the specific preparation method includes the following steps:

[0102] S1: preparing thermally conductive insulating blocks;

[0103] S1.1: Preparation of boron nitride and silicon nitride modified by maleic anhydride grafting: Add unmodified boron nitride and silicon nitride to toluene solvent, add 7% by mass of toluene diisocyanate, stir at room temperature for 24 hours, add anhydride solution, react at 100°C for 7 hours, vacuumize and repeatedly wash, and dry at 70°C to obtain boron nitride and silicon nitride modified by maleic anhydride grafting;

[0104] S1.2: Preparation of surface-modified aluminum nitride: drying aluminum nitride in a vacuum oven at 160°C for 24 hours, and then dispersing aluminum nitride and 3-aminopropyltrimethoxysilane in a mass percentage ratio of 1:0.1 in a 95% ethanol aqueous solution, and ultrasonically treating for 25 minutes; after ultrasonic treatment, magnetic stirring was performed at 85°C for 3 hours, and the mixture was repeatedly washed with anhydrous ethanol, and dried at 120°C for 12 hours to obtain surface-modified aluminum nitride;

[0105] S1.3: Add boron nitride, silicon nitride and aluminum nitride to diphenylmethane bismaleimide resin, and then add diisopropylbenzene peroxide and hot melt adhesive, polyamide, thermoplastic polyimide and polyetherimide in a mass percentage ratio of 1:0.0007:0.08:0.04, and stir evenly;

[0106] S1.4: Pressing and molding at 210°C and 14 MPa in a press to prepare a thermally conductive insulating block;

[0107] S2: Bond the temperature measuring device to the heat-conducting insulating block by using thermal grease;

[0108] S3: pouring insulating resin, and wrapping the metal shielding layer after curing. The pouring process takes 8 hours. After pouring, it is heated and cured in sections, curing at 80°C for 4 hours, and then heating to 130°C for 4 hours.

[0109] S4: pouring a protective encapsulation layer, and preparing a temperature detection device after curing, wherein the pouring process takes 10 hours, and after pouring, it is heated and cured in sections, curing at 75°C for 3 hours, and then heating to 120°C for 5 hours.

[0110] Comparative Example 1

[0111] The difference between Comparative Example 1 and Example 1 is that the mixed fillers in the thermally conductive composite material used in the thermally conductive insulating block are not modified, as follows:

[0112] A high-sensitivity temperature detection device, comprising: a temperature measurement component, a heat-conducting insulating block 4, an electromagnetic shielding layer 6 and a protective packaging layer 7;

[0113] Among them, the thermally conductive insulating block 4 is a thermally conductive composite material, which is prepared by pressing diphenylmethane bismaleimide resin and mixed filler; the mass percentage ratio of diphenylmethane bismaleimide resin to the mixed filler is 100:350; among them, the particle size of boron nitride is 40μm, the particle size of silicon nitride is 6μm, and the particle size of aluminum nitride is 35nm; the mass percentage of boron nitride, silicon nitride and aluminum nitride is 1:1.2:0.8.

[0114] A high-sensitivity temperature detection device is prepared by casting, and the specific preparation method includes the following steps:

[0115] S1: preparing thermally conductive insulating blocks;

[0116] S1.1: adding unmodified boron nitride, silicon nitride and aluminum nitride to diphenylmethane bismaleimide resin, and then adding diisopropylbenzene peroxide and hot melt adhesive, polyamide, thermoplastic polyimide and polyetherimide in a mass percentage ratio of 1:0.0005:0.05:0.03, and stirring evenly;

[0117] S1.2: Pressing and molding at 210°C and 14 MPa on a press to prepare a thermally conductive insulating block;

[0118] S2: Bond the temperature measuring device to the heat-conducting insulating block by using thermal grease;

[0119] S3: pouring insulating resin, and wrapping the metal shielding layer after curing. The pouring process takes 8 hours. After pouring, it is heated and cured in sections, curing at 80°C for 4 hours, and then heating to 130°C for 4 hours.

[0120] S4: pouring a protective encapsulation layer, and preparing a temperature detection device after curing, wherein the pouring process takes 10 hours, and after pouring, it is heated and cured in sections, curing at 75°C for 3 hours, and then heating to 120°C for 5 hours.

[0121] Comparative Example 2

[0122] The difference between Comparative Example 2 and Example 1 is that the filler in the thermally conductive composite material used in the thermally conductive insulating block only includes silicon nitride with a particle size of 6 μm, as follows:

[0123] A high-sensitivity temperature detection device, comprising: a temperature measurement component, a heat-conducting insulating block 4, an electromagnetic shielding layer 6 and a protective packaging layer 7;

[0124] Among them, the thermally conductive insulating block 4 is a thermally conductive composite material, which is prepared by pressing diphenylmethane bismaleimide resin and modified filler; the mass percentage ratio of diphenylmethane bismaleimide resin to modified filler is 100:350; the modified filler is silicon nitride modified by acid anhydride grafting, and the particle size of silicon nitride is 6μm.

[0125] A high-sensitivity temperature detection device is prepared by casting, and the specific preparation method includes the following steps:

[0126] S1: preparing thermally conductive insulating blocks;

[0127] S1.1: Preparation of silicon nitride grafted with maleic anhydride: unmodified silicon nitride was added to a toluene solvent, 5% by mass of toluene diisocyanate was added, stirred at room temperature for 22 hours, anhydride solution was added, reacted at 85°C for 6 hours, vacuumed and repeatedly washed, and dried at 60°C to obtain silicon nitride grafted with maleic anhydride;

[0128] S1.2: Add silicon nitride to diphenylmethane bismaleimide resin, and then add diisopropylbenzene peroxide and hot melt adhesive, polyamide, thermoplastic polyimide and polyetherimide in a mass percentage ratio of 1:0.0005:0.05:0.03, and stir evenly;

[0129] S1.3: Pressing and molding at 210°C and 14 MPa in a press to prepare a thermally conductive insulating block;

[0130] S2: Bond the temperature measuring device to the heat-conducting insulating block by using thermal grease;

[0131] S3: pouring insulating resin, and wrapping the metal shielding layer after curing. The pouring process takes 8 hours. After pouring, it is heated and cured in sections, curing at 80°C for 4 hours, and then heating to 130°C for 4 hours.

[0132] S4: pouring a protective encapsulation layer, and preparing a temperature detection device after curing, wherein the pouring process takes 10 hours, and after pouring, it is heated and cured in sections, curing at 75°C for 3 hours, and then heating to 120°C for 5 hours.

[0133] Comparative Example 3

[0134] The difference between Comparative Example 3 and Example 1 is that the heat conducting block is made of polyimide resin, as follows:

[0135] A high-sensitivity temperature detection device, comprising: a temperature measurement component, a heat-conducting insulating block 4, an electromagnetic shielding layer 6 and a protective packaging layer 7;

[0136] The thermally conductive insulating block 4 is made of polyimide resin.

[0137] A high-sensitivity temperature detection device is prepared by casting, and the specific preparation method includes the following steps:

[0138] S1: preparing thermally conductive insulating blocks;

[0139] S1.1: The polyimide resin is pressed and molded by a press at 210° C. and 14 MPa to prepare a thermally conductive insulating block;

[0140] S2: Bond the temperature measuring device to the heat-conducting insulating block by using thermal grease;

[0141] S3: pouring insulating resin, and wrapping the metal shielding layer after curing. The pouring process takes 8 hours. After pouring, it is heated and cured in sections, curing at 80°C for 4 hours, and then heating to 130°C for 4 hours.

[0142] S4: pouring a protective encapsulation layer, and preparing a temperature detection device after curing, wherein the pouring process takes 10 hours, and after pouring, it is heated and cured in sections, curing at 75°C for 3 hours, and then heating to 120°C for 5 hours.

[0143] The above examples 1-3 are compared with comparative examples 1-3, and the specific results are shown in Table 1:

[0144] Table 1 Performance comparison of different embodiments and comparative examples

[0145]

[0146] According to the results of the embodiments and comparative examples in the above table, the analysis is as follows: It can be seen from the results of the embodiments and comparative example 1 that the thermal conductivity, breakdown strength and volume resistivity of the temperature detection device of the present invention are significantly improved by using the thermally conductive insulating block prepared by the modified mixed filler. Compared with the results of comparative example 2, it can be seen that the mixed filler formed by compounding micron-level particle size and nano-level particle size can improve the thermal conductivity, breakdown strength and volume resistivity of the temperature detection device. It can be seen from the results of the embodiments and comparative example 3 that the thermal conductivity of the thermally conductive insulating block prepared by using the resin without adding filler is extremely low and cannot meet the thermal conductivity requirements; in addition, the viscosity of the thermally conductive insulating block prepared by using the modified mixed filler when not cured is in the most reasonable range, which is convenient for processing.

[0147] In summary, the thermally conductive insulating block prepared by the mixed filler obtained by different modifications of micron-level fillers and nano-level fillers in the present invention has the advantages of high thermal conductivity and good insulation performance. The temperature detection device prepared using the thermally conductive insulating block also has excellent sensitivity, thermal conductivity and insulation performance, so that the temperature detection device of the present invention can be safely used in strong electric and magnetic environments and ensure the accuracy and sensitivity of the measurement.

[0148] The above introduces the preferred embodiments of the present invention, which is intended to make the spirit of the present invention clearer and easier to understand, but is not intended to limit the present invention. All modifications, substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection outlined by the claims attached to the present invention.

Claims

1. A high-sensitivity temperature detection device, characterized in that: The temperature detection device comprises: a temperature measurement component, a heat-conducting insulating block (4), an electromagnetic shielding layer (6) and a protective packaging layer (7); The thermally conductive insulating block (4) is a thermally conductive composite material, which is prepared by pressing diphenylmethane bismaleimide resin and modified mixed filler; The mass percentage ratio of the diphenylmethane bismaleimide resin to the modified mixed filler is 100:(300-400); The modified mixed filler is boron nitride and silicon nitride modified by acid anhydride grafting, and aluminum nitride modified by 3-aminopropyltrimethoxysilane surface modification; The particle size of the boron nitride is 20-50 μm, the particle size of the silicon nitride is 2-10 μm, and the particle size of the aluminum nitride is 20-50 nm; The mass percentage of the boron nitride, silicon nitride and aluminum nitride is 1:(1.1-1.3):(0.8-0.9).

2. The temperature detection device according to claim 1, characterized in that: The temperature measuring component comprises a temperature sensor (3), a temperature measuring circuit board (1), a power supply element (2) and electric wires, and the temperature measuring component is coated with an insulating resin (5).

3. The temperature detection device according to claim 1, characterized in that: The heat-conducting insulating block (4) comprises a heat-conducting joint (41) and a detachable heat-conducting block (42); the heat-conducting joint (41) is connected to the temperature sensor (3).

4. The temperature detection device according to claim 1, characterized in that: The specific method of the anhydride grafting modification is: adding unmodified boron nitride and silicon nitride to an organic solvent, adding isocyanate with a mass fraction of 4-7%, stirring at room temperature for 20-24 hours, adding anhydride solution, reacting at 75-100°C for 5-7 hours, repeatedly washing after vacuuming, and drying at 50-70°C to obtain boron nitride and silicon nitride modified by acid anhydride grafting.

5. The temperature detection device according to claim 4, characterized in that: The molar percentage of the acid anhydride to the isocyanate is (1-1.2):1, the acid anhydride is selected from at least one of unsaturated acid anhydride, maleic anhydride, and methyl sodium diisocyanate, and the isocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate.

6. The temperature detection device according to claim 4 or 5, characterized in that: The surface modification method of the aluminum nitride is as follows: drying the aluminum nitride in a vacuum oven at 140-160° C. for 20-24 hours, dispersing the dried aluminum nitride and 3-aminopropyltrimethoxysilane in an ethanol aqueous solution with a mass fraction of 93-95%, and ultrasonically treating for 10-25 minutes; after the ultrasonic treatment, magnetically stirring at 75-85° C. for 1.5-3 hours, repeatedly washing with anhydrous ethanol, and drying at 100-120° C. for 10-12 hours to obtain the surface-modified aluminum nitride.

7. The temperature detection device according to claim 6, characterized in that: The mass percentage ratio of the aluminum nitride to 3-aminopropyltrimethoxysilane is 1:(0.03-0.10).

8. The temperature detection device according to claim 1, characterized in that: The electromagnetic shielding layer (6) comprises a metal dot matrix structure layer (62) and a polyimide base film layer (61), the metal is selected from any one of copper, aluminum, silver and gold, and the thickness of the electromagnetic shielding layer (6) is 1-100 nm.

9. A method for preparing a temperature detection device according to any one of claims 1 to 8, characterized in that: The temperature detection device is prepared by casting, specifically: S1: preparing a thermally conductive insulating block (4); S2: bonding the temperature measuring device to the heat-conducting insulating block (4) by means of heat-conducting silicone grease; S3: pouring insulating resin (5), and wrapping the metal shielding layer (6) after curing; S4: pouring a protective encapsulation layer (7), and preparing the temperature detection device after curing.

10. The preparation method according to claim 9, characterized in that: in, The S1 comprises the following steps: Step 1: preparing boron nitride and silicon nitride modified by anhydride grafting; Step 2: preparing surface-modified aluminum nitride; Step 3: Add boron nitride, silicon nitride and aluminum nitride to diphenylmethane bismaleimide resin, then add diisopropylbenzene peroxide and auxiliary materials, and stir evenly; Step 4: Prepare the thermally conductive insulating block (4) by compression molding.

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