Thermal adhesive tape is also called thermal tape. Thermal adhesive tape is made of acrylic polymer mixed with thermal ceramic powder, coated on both sides of glass fiber cloth, and compounded with silicone adhesive. It has the characteristics of high thermal conductivity and insulation, and has certain properties. Excellent softness, compressibility, conformability, strong viscosity, and a wide temperature range.
Thermal adhesive tape is widely used in bonding heat sinks, heat dissipation modules, CPU microprocessor heat dissipation, LED lamps and lanterns, filling the gaps between PCB, metal components and chassis, not only filling uneven surfaces, but also The heat is conducted out, and it can be used without changing any components even in a closed space, which fully reflects the thermal conductivity of this thermally conductive material and the self-adhesive properties of the pressure-sensitive adhesive tape for easy use.
So what are the steps to use the thermal adhesive tape?
The thermal adhesive tape should pay attention to the operation method when bonding. It is strictly forbidden to touch the surface with hands or other non-adhesive objects, and it is strictly forbidden to repeatedly peel it. The bonded surface should be kept clean and dry. affect the bond strength.
Step 1: Clean the surface of the device with a lint-free cotton cloth.
Step 2: Use a cotton cloth soaked in industrial cleaner to clean the surface of the device to remove grease, and do not touch the clean surface during installation.
Step 3: Tear off the protective film on one side of the adhesive, do not touch the adhesive surface with your fingers.
Step 4: Stick it on the surface of the device, and press lightly for five seconds from the center of the bonding area to the surrounding area to ensure that the double-backed tape is in complete contact with the surface of the heat sink.
Step 5: Tear off the protective film on the other side of the backing tape and follow the same method as the third and fourth steps to make the double-backed tape and the chip stick firmly.
Insulating materials are non-conductive materials under the allowable voltage, but not absolutely non-conductive materials. Under the action of a certain applied electric field strength, processes such as conduction, polarization, loss, and breakdown will also occur, and long-term use will also occur. .
The resistivity of insulating materials is very high, usually in the range of 1010 to 1022 Ω·m. As in a motor, the insulating material around the conductors isolates the turns and from the grounded stator core to ensure the safe operation of the motor.
Insulating materials are the foundation and guarantee for the development of electrical products, and play a particularly important role in the development of electrical machinery and electrical industries. The development and progress of insulating materials depends on the development of polymer materials and directly restricts and affects the development and progress of electrical products. .
Insulation material is the key to the advanced technology of electrical products, and it is also an important guarantee for the long-term safe and reliable operation of electrical products. Therefore, it is required to continuously develop new varieties of insulating materials and improve product performance and quality to meet the needs of the continuous development of electrical products.
There are many types of insulating materials, which can be divided into three categories: gas, liquid and solid. Commonly used gas insulating materials include air, nitrogen, and sulfur hexafluoride insulating PC films.
Liquid insulating materials mainly include mineral insulating oil and synthetic insulating oil (silicone oil, dodecylbenzene, polyisobutylene, isopropyl biphenyl, diarylethane, etc.).
Solid insulating materials can be divided into two categories: organic and inorganic. Organic solid insulating materials include insulating paint, insulating glue, insulating paper, insulating fiber products, plastics, rubber, varnished varnished pipes and insulating impregnated fiber products, electrical films, composite products and adhesive tapes, electrical laminates, etc. Inorganic solid insulating materials mainly include mica, glass, ceramics and their products. In contrast, solid insulating materials are diverse and most important.
Different electrical equipment has different requirements for the performance of insulating materials. Insulation materials for high-voltage electrical installations such as high-voltage motors and high-voltage cables require high breakdown strength and low dielectric loss. Low-voltage electrical appliances take mechanical strength, elongation at break, heat resistance grade, etc. as the main requirements.
The macroscopic properties of insulating materials such as electrical properties, thermal properties, mechanical properties, chemical resistance, weather resistance, corrosion resistance and other properties are closely related to its chemical composition and molecular structure. Inorganic solid insulating materials are mainly composed of silicon, boron and various metal oxides, mainly ionic structure, the main feature is high heat resistance, working temperature is generally greater than 180 ℃, good stability, resistance to atmospheric aging, resistance Good chemical properties and long-term aging performance under the action of an electric field; but high brittleness, low impact strength, high pressure resistance and low tensile strength; poor craftsmanship. Organic materials are generally polymers with an average molecular weight between 104 and 106, and their heat resistance is usually lower than that of inorganic materials. The heat resistance of materials containing aromatic rings, heterocyclic rings and elements such as silicon, titanium, and fluorine is higher than that of general linear polymer materials.
The important factors affecting the dielectric properties of insulating materials are the strength of molecular polarity and the content of polar components. The dielectric constant and dielectric loss of polar materials are higher than those of non-polar materials, and it is easy to adsorb impurity ions to increase conductivity and reduce its dielectric properties. Therefore, attention should be paid to cleanliness during the manufacturing process of insulating materials to prevent pollution. Dielectrics for capacitors require high dielectric constants to improve their specific characteristics.
When it comes to thermal materials in our daily life, most people think of metal materials for the first time, because most metal materials are excellent conductors of heat. This paper mainly introduces the current mainstream non-high thermal metal materials, especially various non-metal thermal materials dominated by oxides.
At present, the most widely used non-metal thermal conductive materials are aluminum oxide (AL2O3), silicon oxide, zinc oxide, aluminum nitride, boron nitride, silicon carbide, graphite, etc. In the industries of electronic circuits and thermally conductive polymer materials, micro-alumina and silicon micro-powders are the main bodies, nano-alumina and nitrides are used as filling powders in the field of high thermal conductivity; while zinc oxide is mostly used as thermal paste (thermal grease) For filling.
The following is a list of thermal conductivity of some non-metallic materials (this table is the measured value under the same conditions, the test value of the same material will be different in different environments):
Medium Density Silicone
PP+25% glass fiber
The following is a brief introduction to the advantages and disadvantages of several commonly used non-metallic thermally conductive materials:
Advantages: The thermal conductivity is very high, the thermal expansion coefficient is small, and it is a good heat-resistant thermal shock material. At present, it is mostly used as a heat exchanger material for high temperature structural parts. The thermal conductivity of single crystal can be as high as 275 W/M·K
Disadvantages: Expensive, usually more than 150$ per kilogram. After the aluminum nitride absorbs moisture, it will react with water and hydrolyze AlN+3H20=Al(OH)3+NH3. The Al(OH)3 generated by the hydrolysis will interrupt the thermal conduction path, thereby affecting the transfer of phonons, so it is made into products. The thermal conductivity is low. Even with silane coupling agent for surface treatment, 100% filler surface coverage cannot be guaranteed. Simply using aluminum nitride can achieve high thermal conductivity, but the viscosity of the system increases greatly, which severely limits the application field of the product.
Boron Nitride (BN)
Advantages: Excellent thermal conductivity and stable properties. BN not only its structure but also its properties are very similar to graphite, and it is white, so it is commonly known as: white graphite. The hardness is second only to diamond, and it is a superhard material.
Disadvantages: The price is relatively high, and the market price ranges from tens of dollars to thousands of dollars (depending on the quality of the product). Although the use of boron nitride can achieve high thermal conductivity, similar to aluminum nitride, a large amount of filling The viscosity of the post-system is greatly increased, which seriously limits the application field of the product. I heard that some foreign manufacturers produce spherical BN, which has large particle size, small specific surface area, high filling rate, not easy to increase viscosity, and extremely high price.
Advantages: Silicon carbide (SiC) is made from raw materials such as quartz sand, petroleum coke (or coal coke), and wood chips (salt is required to produce green silicon carbide) through high temperature smelting in a resistance furnace. Good oxidation resistance and stable chemical properties.
Disadvantages: The carbon and graphite produced in the synthesis process are difficult to remove, resulting in low product purity and high electrical conductivity, which are not suitable for electronic glue. The density is high, and it is easy to precipitate and stratify in the silicone rubber, which affects the application of the product. It is more suitable for epoxy glue.
Advantages: The most stable phase of all aluminas. The crystal size distribution is uniform, the purity is high, and the dispersion is high. It has a low specific surface and is inert to high temperature. Affordable.
Disadvantages: Low addition amount. In liquid silica gel, the maximum addition amount of ordinary acicular alumina is generally about 300 parts, and the thermal conductivity of the obtained product is limited.
Advantages: The filling amount is large. In the liquid silica gel, the spherical alumina can be added to a maximum of 600~800 parts, and the obtained product has a high thermal conductivity.
Disadvantages: more expensive, but lower than boron nitride and aluminum nitride.
Zinc oxide (ZnO)
Advantages: Good particle size and uniformity, suitable as a raw material for the production of thermal grease.
Disadvantages: Low thermal conductivity, not suitable for producing high thermal conductivity products; light weight, strong viscosity, not suitable for potting.
Quartz Powder (Crystalline)
Advantages: High density, suitable for potting; low price, suitable for mass filling, reducing cost.
Disadvantages: Low thermal conductivity, not suitable for the production of high thermal conductivity products. Density is higher and delamination may occur.
Through the above detailed description, you should know that different fillers have their own characteristics. When choosing fillers, you should make full use of the advantages of each filler, and use several fillers for mixed use to play a synergistic effect, which can not only achieve high thermal conductivity, but also Effectively reduce costs, while ensuring the compatibility of fillers and polymers.
Although silica gel products can be seen all over the street now, we can often use silica gel in our daily life, because the silica gel industry has developed rapidly in China in recent years, and there have been many thermal conductive silica gel, silica gel glue, silica gel Silicone products such as kitchen utensils, silicone household daily necessities and silicone gifts, people gradually understand silicone. So what is silicone? What are the advantages and disadvantages of silicone products? Today, Nuofeng Thermal Conductive Silicone Products Factory will take you to know about the knowledge of silicone products.
What is silicone?
Silica gel alias: Silica gel, is a highly active adsorption material, is an amorphous substance. The main component of silica gel is silicon dioxide, which is chemically stable and non-flammable.
Chemical formula xSiO2 yH2O. Transparent or milky white granular solid. It has an open porous structure, strong adsorption, and can adsorb a variety of substances. Dilute sulfuric acid (or hydrochloric acid) is added to the aqueous solution of water glass and allowed to stand to form a hydrous silicic acid gel and solidify. The electrolyte Na+ and SO4 2-(Cl-) ions dissolved in it are removed by washing with water, and the silica gel can be obtained after drying. If it absorbs moisture, some silica gels absorb about 40% or even 300% of moisture. For gas drying, gas absorption, liquid dehydration, chromatography, etc., also used as a catalyst. If cobalt chloride is added, it turns blue when dry and red when it absorbs water. Recyclable for repeated use.
Advantages of silicone products
High temperature resistance: the applicable temperature range is -40 to 230 °C, and it can be used in a constant temperature and humidity test chamber.
Easy to clean: The silica gel products produced by silica gel can be cleaned by rinsing with clean water after use, and can also be cleaned in the dishwasher.
Long lifespan: The chemical properties of the silicone material are very stable, and the products made have a longer lifespan than other materials. For example, the lifespan of thermally conductive silica gel can reach 10 years or even longer.
Soft and comfortable: Thanks to the softness of the silicone material, it is extremely flexible and does not deform.
Various colors: According to the needs of customers, different beautiful colors can be deployed, and personalized styles can be customized.
Environmentally friendly and non-toxic: no toxic and harmful substances are produced from the entry of raw materials to the delivery of finished products.
Electrical insulation performance: Silicone rubber has high resistivity, and its resistance value can remain stable in a wide temperature range and frequency range. At the same time, silica gel has good resistance to high-voltage corona discharge and arc discharge, such as high-voltage insulators, TV high-voltage caps, electrical components, thermal pads, etc.
Low temperature resistance: The critical temperature of ordinary rubber is -20°C to -30°C, but silicone rubber still has good elasticity at -60°C to -70°C, and some specially formulated silicone rubber can also be used. Withstand extremely low temperatures, such as low temperature silicone seals, etc.
Conductivity: When conductive fillers (such as carbon black) are added, silicone rubber has good conductivity, such as keyboard conductive contact points, electric heating element parts, antistatic parts, shielding for high-voltage cables, medical physiotherapy conductive films, etc.
Weather resistance: ordinary rubber is rapidly degraded under the action of ozone generated by corona discharge, while silicone rubber is not affected by ozone, and its physical properties only change slightly under ultraviolet light and other climatic conditions for a long time, such as outdoor Sealing materials used, etc.
Thermal conductivity: When some thermally conductive fillers are added, silicone rubber has good thermal conductivity, such as heat sinks, thermally conductive gaskets, thermal rollers for copiers, fax machines, etc.
Radiation resistance: The radiation resistance of silicone rubber containing phenyl is greatly improved, such as electrical insulation cables, connectors for nuclear power plants, etc.
Disadvantages of silicone products
Similar products are more expensive than plastic, plastic and plastic products.
The molding time is longer than others, and the silica gel needs to be cross-linked (or vulcanized).
The waste cannot be recycled: Since the silicone products are all vulcanized and formed, the scraps, wastes and waste silicone products cannot be re-mixed and used, which also increases the material cost virtually, which is not conducive to environmental protection and sustainable development. .
The superior performance, coupled with the fact that silica gel is a non-petroleum product, does not depend on the increasingly scarce petroleum resources, it is the general trend that silica gel products become substitutes for similar plastic products. At the same time, silica gel products can be applied to many applications that plastic products cannot. Such as thermal conductive silica gel, etc., the application prospect is very broad.
RTV adhesive is a room temperature vulcanized silicone rubber adhesive, RTV is the abbreviation of English (Room Temperature Vulcanized Silicone Rubber), a silicone rubber that can be vulcanized at room temperature. Silicone rubber is a straight-chain high-molecular-weight polysiloxane with a molecular weight of more than 150,000. Its structural form is similar to that of silicone oil. Usually, both ends of its molecular chain contain active groups such as hydroxyl and vinyl. Low.
RTV adhesive is prepared by compounding components such as silicone rubber, cross-linking agent and filler. There are two kinds of one-component RTV adhesive and two-component RTV adhesive. RTV silicone glue has a long storage period and stable performance. It can bond common metal and non-metal materials, so it is suitable for bonding and sealing between various metals and between metal and non-metal materials.
Introduction to The Characteristics of RTV Silicone Glue
After curing, the RTV silicone glue thermal gel presents an elastic colloid. The elastic colloid can play a protective role when it vibrates and is not easy to break.
RTV silicone glue is more convenient to vulcanize. Whether it is a one-component product or a two-component product, it can be vulcanized at room temperature. It can be cured without heat treatment, and it will not shrink or release toxic substances after curing. , performance safety is guaranteed.
RTV glue also has the characteristics of long-term storage resistance. The shelf life is 12 months. During the storage period, as long as there is no air or moisture, the performance is the same as before, and the bonding strength is strong.
The reason why RTV glue thermal gel can be used in electrical appliances is that it has good electrical insulation properties after curing. It is suitable for -60 ℃ ~ 200 ℃ working temperature, can meet the electrical insulation requirements, and is safer to use, even if the electrical appliance is short-circuited , and will not cause a fire.
RTV gel glue has a wide range of applications, not only for bonding and fixing electrical components, but also for bonding electrical or electronic instrument housings. After curing, the waterproof performance is very good, and it will not change after many years of use.
RTV silicone glue does not have any corrosiveness. Although RTV silicone is a kind of adhesive, it will not corrode metal, ceramics, plastics and circuits after curing, and it has no effect on the human body. For this, big brand products Do better, such as CoolThermo, focus on the research of rtv silicone glue, provide customized rtv silicone glue application solutions, widely used, can be used in new energy, military, medical, aviation, ships, electronics, automobiles, instruments , power supply, high-speed rail and other industries.
RTV silicone glue is now an indispensable material in the manufacturing process of electrical appliances, electronics, automobiles, instruments and other fields. If the construction volume is large, it can be purchased in large quantities, as long as you pay attention to storage.
The price of silicone electronic potting glue in the market is high and low, and the price of some electronic potting glue is far lower than the average market price. Why? Is their technology advanced and can effectively control production costs? In fact, the reason is that they add low-cost white oil to the potting compound material, which controls costs and disrupts the market.
What is white oil?
White oil, also called white mineral oil, is a special deep-refined mineral oil. Transparent, colorless, odorless, chemically inert, the basic substances are saturated hydrocarbons, aromatic hydrocarbons, etc., and the molecular weight is usually between 250 and 450. The boiling point is generally within 150 °C. It is widely used in daily chemical, pharmaceutical, food, rubber and plastic, agriculture and other industries.
Why does adding white oil reduce production costs?
Because the price of white oil is relatively low. For example, the general market price of silicone oil is 30 yuan/kg, while the price of white oil is only 10 yuan/kg. On the premise of ensuring the acceptance quality of electronic potting glue, 20% white oil can be added, then doping The glue cost of white oil is 26 yuan/kg. In this way, by adding an appropriate proportion of white oil, the price of electronic potting glue can be reduced and the potting glue market can be seized.
What is the effect of electronic potting compounds with added white oil?
We know that silicone oil is a polymer material with a siloxane structure and has organic and inorganic properties, while white oil is an organic polymer with a carbon structure and has no inorganic properties. Since white oil is chemically inert, it does not participate in the cross-linking reaction of organic silica gel.
When the silicone is cured, the free white oil slowly seeps out of the glue. Once the electronic potting compound doped with white oil is used on electronic products such as driving power supply, the following situations may occur:
Various physical properties are poor, such as tensile strength and tear strength will decrease;
The ability of heat dissipation and flame retardancy is poor, and it is difficult to effectively improve the heat dissipation capacity and safety factor of electronic products, which is prone to accidents;
Poor high and low temperature resistance, poor weather resistance, and easy cracking of the colloid, allowing rainwater to penetrate into the electronic components from the cracks, reducing the moisture-proof ability of electronic products, and causing electronic components to fail;
The electrical performance and insulation ability are poor, which affects the anti-electromagnetic interference ability of electronic components after potting, and is prone to failure.
How to detect whether white oil is added to electronic potting compound?
Since the boiling point of white oil is relatively low, less than 150 °C, and the boiling point of silicone oil is around 200 °C, the simple method in the laboratory is to test the volatile content of the uncured or cured potting compound. The test method is: oven at 150 °C After baking for 3 hours, the weight difference after volatilization was measured. The volatile matter of normal electronic potting glue is less than 1%, and the volatile matter of added white oil is greater than 5%. When the volatile content is abnormally high, it can be judged that white oil is added to the electronic potting compound.
In short, when we choose electronic potting glue, we can’t blindly covet cheap prices, we must consider the comprehensive selection of product quality and company services.
Thermal gel is currently a widely used heat dissipation product in the electronics industry. This product is mainly used in low-power heating devices, which can prevent electronic devices from overheating and malfunction for a long time. However, when many electronic industries are using thermal gel products, they are often not familiar with the performance of the products, so there are often some ridiculous low-level misoperation problems.
Different products have certain differences in the method of use. We must have the correct operation method in the process of use. These are very important to all of us, so how to correctly operate in normal times? What about using thermal gel? This is also a concern of many people. If you can have a better understanding of these aspects in advance, the subsequent use will be easier.
Before using the thermal gel, we must do a good job of surface treatment, remove those vivid substances that exist on its own surface, and do a good job of polishing through a variety of different methods, so as to improve the repaired surface as soon as possible. This kind of roughness can be properly scrubbed and cleaned with some reagents during use, so that the surface will be cleaner. In the process of application, the surface can be glued, so that it can really ensure that the color is uniform and must be used within the specified time.
After the surface treatment is done, we must apply it. When applying it, it should be relatively uniform. At the same time, we must also do a good job of anti-negative pressure, so as to ensure better filling of the material and achieve better results. If you need multiple layers of glue When using it, you should do some treatment on the surface, and then do some smearing work. During the application process, you must pay attention to the specific temperature. At the same time, you should also pay attention to the correct use method. Gel storage works.
The demand for automotive adhesives and sealants is growing rapidly. Adhesives and sealants for automobiles are an important auxiliary material for automobile production. With the development of automobiles in the direction of lightweight, high-speed energy saving, safety and comfort, low cost, long life and pollution-free applications are becoming more and more important.
In terms of glues for automobile manufacturing, the average dosage of organic silica gel is 300g/vehicle, the average dosage of polyurethane glue is 900g/vehicle, acrylate is 66g/vehicle, and anaerobic adhesive is 120g/vehicle; The average amount of silica gel is 60g/vehicle, and the average amount of polyurethane glue is 40g/vehicle.
The application of adhesives and bonding technology in automobile manufacturing can not only enhance automobile structure, fasten rust prevention, heat insulation and vibration reduction, interior and exterior decoration, etc., but also replace traditional processes such as welding and riveting in certain parts, simplify production processes and optimize products. structure. Therefore, adhesives play an increasingly important role in the lightweight, energy saving and consumption reduction of automobiles, prolonging service life and improving performance.
From the perspective of the working parts and functions involved in the entire automobile manufacturing process, automotive adhesives can be roughly divided into adhesives for welding processes, adhesives for painting processes, adhesives for interior parts, adhesives for assembly parts, and special adhesives. Craft glue and other five categories.
Adhesive parts for automotive applications
Seat pressure sensor
Car anti-theft coil
Tire pressure sensor
Seat heating device
Car remote control
Seat belt sensor
Among them, the glue for welding process is mainly used to replace spot welding or reduce welding points, and play the role of strengthening structure, sealing and rust prevention, vibration reduction and noise reduction. Its main varieties are:
Hemming adhesive: It is used in crimping structures such as doors, hoods, and trunk lids. It has high bonding strength and has completely replaced spot welding structures. One-component epoxy resin is generally used for this kind of glue, and the dosage for a bicycle is about 200g;
Spot welding sealant: It is pre-applied on the overlapping parts of the steel plate welding, and the gap is filled after spot welding to ensure sealing and prevent rust. For those parts that are masked after assembly and difficult to apply weld sealant, spot welding sealant is even more indispensable;
Expansion damping glue: This kind of glue is often used between the inner and outer panels of the door, between the outer body cover and the reinforcing ribs. It is generally made of synthetic rubber or resin and combined with a foaming agent. After curing and expansion, the cover can be combined with the reinforcing rib to play the role of vibration reduction and noise reduction.
There are not many varieties of glue used in the coating process, but it is the most used type in automobiles. Among them, the truck is about 2kg, and the car is more than 5kg. It is mainly used for automobile sealing, leakage prevention, rust prevention and buffering of sand and gravel to the chassis when the car is running at high speed. impact and reduce the noise in the car, such as pvc plastisol and its modified products.
Adhesives for interior parts are mainly used in body roof, door inner panel waterproof membrane and windshield lining, etc., to increase the beauty of the car, enhance the rigidity of the body, and seal, such as neoprene, butyl, and polyurethane glue. Wait.
The glues used for assembly parts mainly include anaerobic glue, silicone sealant, etc., which are mainly used in the assembly of automobile engines, gearboxes and chassis.
In addition, in the process of automobile manufacturing, some special process adhesives, such as phenolic resin adhesive used for the bonding of brake shoes and friction linings, are also used, which can replace riveting and have reliable bonding strength, which can reduce noise and prolong friction lining. Service life and other functions; the pressure-sensitive tape used in the car assembly process can protect the car itself from pollution, bump damage, or assist in fixing and positioning when assembling parts.
With the development of the automotive industry, automotive adhesives are developing rapidly from variety to output. The automotive industry has high requirements for the quality, performance and safety of adhesives. Domestic adhesive products are relatively backward and have a single variety, which is difficult to meet the demand. It is necessary to import a large number of high-quality and high-performance adhesives. Therefore, efforts to develop high-quality, high-performance adhesives to meet the needs of the automotive industry are expected to yield high returns. The market demand for automotive adhesives is promising.
The application fields of insulating materials are relatively wide, and different electrical equipment have different usage requirements. When selecting insulating materials, it is necessary to select the appropriate type according to the characteristics of the insulating material itself.
So, how to choose insulating material? What should be paid attention to when choosing insulating materials? Today, CoolThermo thermal insulation material manufacturers will introduce you to the selection methods and skills of insulation materials.
Compression factor. Since many materials increase in thickness after absorbing moisture, the thickness will decrease again after drying. This has higher requirements on the compressibility of insulating materials, and can withstand various deformation and shrinkage conditions.
High heat resistance. For some thermally conductive insulating materials used in specific occasions, there are certain requirements for their heat resistance grades. Such as: the application of solar panels, it has high heat resistance requirements for insulating materials. If the selected insulating material does not meet the corresponding level, it is likely to shorten the service life of the entire device.
Insulation performance. Due to the wide variety of insulating materials, such as cable paper, capacitor paper, thermal insulation sheets, etc., the insulation strength is different. Among them, capacitor paper is the best, followed by cable paper. In the use of different materials, we need to have a basic parameter guide for insulation, and then select appropriate insulation materials according to these parameters.
Mechanical properties. For mechanical equipment in many application fields, vibration, pulling or moving will inevitably occur during use, which makes it difficult to apply insulating materials to small parts. If the mechanical properties of the insulating material are weak, it will be damaged, thereby weakening its insulating properties. Therefore, when selecting insulating materials, it is also an important part to measure its mechanical properties.
Under the action of the electric field, the insulating material will have physical phenomena such as polarization, conductance, dielectric heating, breakdown, etc. While under the action of the electric field, it must also be affected by many factors such as mechanical and chemical, and the long-term work will appear aging phenomenon. Therefore, many faults of electrical products often occur in the insulating part. Only by choosing an insulating material with good compression performance, high heat resistance, strong insulation performance and excellent mechanical properties can long-term stable and continuous operation.
With the rapid development of electronic products, the precision of electronic products has been continuously improved, and many electronic components will generate a lot of heat during use. If this heat is not dissipated in time, it is easy to cause high temperature and overheating of electronic components, resulting in failure and affecting electronic and electrical products. service life.
Therefore, efficient heat dissipation has become the focus of the design, especially on chip processors, LEDs, and power packs. In order to solve this problem, electronic thermal conductive potting compound is generally poured into electronic products as a thermal conductive material, so as to efficiently conduct the heat inside the electronic product to the heat dissipation shell, thereby improving the safety and service life of the electronic product.
There are generally three kinds of potting compounds suitable for pouring on electronic components, namely: epoxy resin potting compound, polyurethane material potting glue and silicone material potting glue (here we call it electronic thermal conductivity potting). Plastic closures). Among them, the most suitable for potting in electronic products is silicone potting compound, because other materials have some unavoidable defects.
The potting compound of epoxy resin material has weak resistance to cold and heat changes. Once it is impacted by cold and heat, the colloid will crack, and moisture such as rainwater and condensation will easily penetrate into the electronic components through the cracks, resulting in electronic components. The device is disconnected, which seriously affects the use of electronic products. Polyurethane potting glue, because of its high toxicity, is easy to cause allergic symptoms, so it is necessary to pay great attention to the production and production.
The silicone-based potting compound has excellent electrical properties and insulating properties. It can be used in electronic components to ensure that the components will not interfere with each other, which can effectively improve the stability of electronic products, and can also play a role in thermal conductivity and flame retardant. , Waterproof and shockproof.
Under normal circumstances, the indicators for measuring electronic thermal conductive potting compounds mainly include the following aspects:
Thermal conductivity is an important parameter to measure the thermal conductivity of thermally conductive materials. The higher the thermal conductivity, the better the thermal conductivity and heat dissipation effect, and the heat generated by the components can be quickly dissipated. When other conditions are constant, the higher the thermal conductivity, the better the electronic thermal conductive thermal potting compound.
Of the three properties of interest are dielectric strength (sometimes also expressed in terms of breakdown voltage) and volume resistivity.
Dielectric strength is a measure of the electrical strength of a material as an insulator. It is defined as the maximum voltage a unit thickness can withstand when a specimen is broken down, expressed as volts per unit thickness. The greater the dielectric strength of a substance, the better its quality as an insulator.
Volume resistivity is the resistance of a material to current per unit volume, which is used to characterize the electrical properties of a material. Generally, the higher the volume resistivity, the higher the effectiveness of the material as an electrically insulating component.
The dielectric constant is used to measure the ability to interfere in electromagnetic fields.
Thirdly: Physical properties – fluidity, density and adhesion
Because the electronic thermal conductive potting compound is fluid, it has a certain fluidity, and the popular thermal potting compound can be used to fill the gap with smaller pores and increase the volume of the thermal conduction and heat dissipation contact surface.
Density (specific gravity) is also an indicator of special concern for electronic thermal conductive potting compounds. Generally, under the same thermal conductivity, the lower the specific gravity, the better. The lower the proportion, it is used in industries such as automotive power supply, which can effectively improve energy efficiency.
The electronic thermal conductive potting compound has a certain viscosity, which can firmly bond the heating device and the heat sink together, so the viscosity is also an important indicator to consider the performance of the thermal conductive electronic potting compound.