1, the ideal resin is smokeless, low toxicity, low cost, does not affect the inherent physical properties of the resin, does not need to add materials, can be directly produced in the resin production plant flame retardant resin. 3) Toughened resin. Compared with the original unsaturated polyester resin varieties, the toughness of the resin has been greatly improved. However, with the development of the downstream industry of unsaturated polyester resin, more new requirements have been put forward for the performance of unsaturated resin, especially in terms of toughness.
2, epoxy resin contains double epoxy group, the need for amine curing agent to participate in the curing reaction, the final product performance and curing agent performance is very large, but the totalThe final curing product of epoxy resin is harder and stronger than the curing product of unsaturated polyester resin, of course, the price of epoxy resin is twice that of unsaturated polyester resin. Generally do artificial stone will choose unsaturated polyester resin, because the price is cheap.
3, but in general, the final curing product of epoxy resin is harder and stronger than the curing product of unsaturated polyester resin, of course, the price of epoxy resin is twice that of unsaturated polyester resin. Generally do artificial stone will choose unsaturated polyester resin, because the price is cheap. And do floor, anti-corrosion coating will choose epoxy resin because of its better performance.
<4, in summary, epoxy resin contains double epoxy groups, the need for amine curing agent to participate in the curing reaction, the final product performance and curing agent performance is very large, but in general, the final curing product of epoxy resin is stronger than the curing product of unsaturated polyester resin hardness and strength, of course, the price of epoxy resin is twice that of unsaturated polyester resin. Generally do fiberglass products will choose unsaturated polyester resin, because the price is cheap.5, epoxy resin and unsaturated resin have superior corrosion resistance. The construction of unsaturated resin is simpler than epoxy resin. The heat resistance of epoxy cured material is generally 80 ~ 100℃. ringThe heat resistant varieties of oxyresin can reach 200 ° C or higher.
1, in general, high frequency can be defined as frequency above 1 GHZ. At present, the most commonly used high-frequency circuit board substrate is a fluorine dielectric substrate, such as polytetrafluoroethylene (PTFE), usually known as Teflon, which is usually used above 5GHz. In addition, there are FR-4 or PPO substrates, which can be used for products between 1GHz and 10GHz, and these three high-frequency substrates have physical property ratiosIt is as follows.
2, high-frequency board refers to a special circuit board with a high electromagnetic frequency, used for PCB in the field of high frequency (frequency greater than 300MHZ or wavelength less than 1 meter) and microwave (frequency greater than 3GHZ or wavelength less than 0.1 meters). It is a circuit board produced on a microwave substrate copper clad plate by using part of the ordinary rigid circuit board manufacturing process or by using a special treatment method. In general, high-frequency boards can be defined as circuit boards with frequencies above 1GHz.
3, high-frequency plate is usually pressed with FR4 glass fiber board, and is the whole epoxy resin glass cloth pressed,In terms of color, the whole board is more uniform and bright. The density is higher than the low frequency board. Generally, high frequency boards are used in circuits with frequencies above 1G. Its dielectric constant is the key, must be very small and stable, medium loss is very small, not easy to absorb moisture, heat, corrosion resistance and other excellent performance.
4, PCB high frequency board is a special circuit board for radio frequency (RF) and microwave frequency band applications, which needs to have better signal transmission performance and anti-interference ability. The following are several common PCB high-frequency plate classification: PTFE (polytetrafluoroethylene) substrate: PTFE is a very common high-frequency plate, with low lossAdvantages such as consumption, low dielectric constant and high insulation impedance. Common PTFE substrates are FR-4 substrate PTFE, RO4350B, RO4003C and so on.
5, high-frequency plate is usually pressed with FR4 glass fiber board, and is the whole sheet of epoxy resin glass cloth pressed, the color of the whole board is more uniform, bright. The density is larger than the low frequency board, which is the weight focus.
6, high-frequency circuit design on the social, economic environment impact has reduced costs, serious harmonic pollution. After inquiring the relevant information, the high frequency circuit board is a special circuit board with high electromagnetic frequency, and the high frequency can be definedThe frequency is above 1GHz. Its physical properties, accuracy and technical parameters are very high, and it is often used in automotive anti-collision systems, satellite systems, radio systems and other fields.
1, the circuit is designed with a switching power supply, in which the switching transformer will make a squeaking noise, which is the sound of the magnetic core is not tight and the oscillation frequency is higher. It's a transformer. They all make sounds just big and small. The squeaking of the high-frequency transformer is not loud and has no effect on the circuitThe impact can be ignored.
2, the lithium battery of the charging treasure and the mobile phone, most of them are 7V, such a voltage is unable to charge the mobile phone, so the charging treasure will be boosted to about 5V, this process needs to boost the voltage coil, you hear the sizzling sound is issued by it, the better charging treasure may sound is relatively small. The inductance on the mainboard of the charging bank occurs in the high-frequency electromagnetic resonance, which has nothing to do with it.
3, millet charger. If it is wireless charging, sometimes he has some sound is very normal, so do not worry about this is also a normal phenomenon when he is chargingIf the sound is larger, you can go to the millet after-sales service to consult and check.
The use of inorganic flame retardants such as hydrated alumina, magnesium, boron, molybdenum compounds and other flame retardant additives, although there is an obvious smoke effect, can produce low smoke and low toxicity flame retardant resin, but if the amount of inorganic flame retardant filler is too large, not only the viscosity of the resin increases, is not conducive to construction, while the resin to add a large number of added flame retardants, will affect the mechanical strength and electrical properties of the resin after curing. At present, many foreign patents have been reported to use phosphorus systemTechnology for producing low toxicity, low smoke flame retardant resin.
High frequency PCB material TU-883 is an FR4 glass epoxy resin laminate with an embedded copper foil layer that provides low dielectric constant and low loss Angle tangent. This material is ideal for use on waveguide circuits or microstrip transmission lines where signals travel along the surface of the board or through holes drilled into the board. High frequency PCB materials provide good power dissipation capability.
Accurate color mixing is more difficult than liquid pigments; It is difficult to change the color in the product line; More systems require phasesOn high drying temperature. Because epoxy powder coatings have many good properties, they are widely used: office and school facilities, refrigerators and freezers, washing machines, radios, lamp shades, bicycle and motor vehicle frames, car driving plates, components and bodies, agricultural machinery equipment, pipeline exterior coatings.
Epoxy resin self-leveling floor construction technology: base inspection and treatment: base inspection includes the determination of concrete moisture content, flatness and strength. Because the flatness and strength measurement is relatively simple, it is not mentioned here, and because the moisture content has a great influence on the film, the determination is introduced.