For the LED plastic radiator ( Figure)

Recently plastic radiator also aroused people's attention. Arguably heat conduction performance is good material is usually a conductive performance is good,, in turn, the worse performance of conductive plastic, its thermal conductivity must be bad. This is inevitable. So apparently good thermal conductivity metal than plastic. In fact also is such. So, can we must not be used to make plastic radiator? Not so! Recent international has developed a variety of thermal conductive plastics and its material mostly in engineering plastics and general plastic for base material, such as PP, ABS, PC, PA, LCP, PPS, PEEK, etc. Then fill in the plastic of some metal oxides, carbon powder, fiber or ceramic powder. Such as PPS ( PPS) Magnesium oxide with large particles ( 40 ~ 325 mesh) Mix can be made into a kind of insulating thermal conductive plastic. The typical thermal conductivity in the range of 1 - 20 W/m- K, can achieve 100 W/m - some grades K。 That figure is about 5 - of traditional plastic 100 times, general plastic thermal conductivity is only 0. 2 W/m- K。 But if you in order to get high thermal conductivity and adding too much metal powder, it becomes electrical conductivity. That cannot be applied in some occasions. Coolploy companies in the United States of some of the properties of thermal conductive plastics is as follows.
　　E4505 ( PC) : 10 w/mk thermal conductive thermal conductivity applications: shell and radiator
D5108 ( PPS) : the coefficient of thermal conductivity thermal insulation application: 10 w/mk board/chip
D5506 ( 连结控制协定) : the coefficient of thermal conductivity thermal insulation application: 10 w/mk board/chip
D8102 ( TPE) : the coefficient of thermal conductivity thermal insulation application: 3 w/mk interface
E5101 ( PPS) : the coefficient of thermal conductivity of 20 w/mk thermal conductive application: radiator.
so why thermal conductive plastic can also make the radiator? It can heat dissipation performance and traditional aluminum radiator than? Can completely, even better! Can you believe it?
we know that any radiator, in addition to can quickly to the heat from the heat source conduction to the surface of the radiator, finally depends on the heat convection and radiation are scattered into the air. Coefficient of thermal conductivity is high, only solved the problem of heat transfer is fast, and the cooling heat dissipation area, shape, is mainly from natural convection and thermal radiation ability, these almost nothing to do with thermal conductivity of materials. So as long as there is some heat conduction ability, plastic radiator can still be good radiator!
in general, if the surface of the heat from the heat source to the radiator distance is less than 5 mm, so as long as the coefficient of thermal conductivity is greater than 5, the heat dissipation is dominated by convection and conduction heat dissipation can't afford to have any effect at this moment. It can be seen from the curve.
in figure 1. The relationship between thermal conductivity and convection heat conduction
in figure 1 gives the coefficient of thermal conductivity and the relationship between the conduction, convection. Figure in the abscissa is the coefficient of thermal conductivity, the ordinate is the temperature difference of heat source and the environment. The curve of all sorts of color is the heat source and distance on the surface of the radiator. If the distance is less than 5 mm ( The green curve) , so as long as the coefficient of thermal conductivity is greater than 5, the cooling capacity is completely determined by convection. The smaller the difference in temperature, the smaller the distance, the less important thermal conductivity.
and for the ideal good radiator, about 7 into heat by convection, and 3 into heat by radiation.
the radiation thermal conductive plastic cooling capacity is not at all. Here are all kinds of material coefficient of thermal radiation.

so, if two identical radiator shape, one is made of aluminum, is a thermal conductive plastic, if made of aluminum radiator without black finish, the cooling capacity is less black thermal radiator made of plastic! Because of the convection is the same, and radiation radiator with plastic better! Here in a Shanghai company after the new material's thermal plastic, for example, the material of the indicators are as follows:

compared with commonly used aluminum radiator, plastic thermal conductive materials can not be ignored, and some other advantages.

compared with the traditional materials and thermal conductive polymer with higher resistance to flexing and stretching stiffness, but the impact strength is poorer, and its inherent low thermal expansion coefficient can effectively reduce the shrinkage of fabrication. Actually can think that its biggest advantage is that insulation. Aluminum radiator because of its good conductivity tend to be isolated power supply through the CE or UL feared a factor, and plastic radiator can be adopted the isolation type power supply at the same time and don't have to worry about their safety. In addition, its density to lighter than aluminium. The density of aluminum is 2700 kg/m3, and the density of plastic is 1420 kg/m3, almost half of aluminum, so the same shape of the radiator, radiator plastic weight is only half of the aluminum. And processing is simple, the molding cycle can be shortened 20 - 50%, which also reduces the cost of pressure. Below for Shanghai Long Mao company production using Shanghai after the new material's thermal conductivity plastic shell radiator LED bulb light. It can be spread around 8 watts of power. This power is nearing the limit of ball steep light power ( 9 w) 。 To further strengthen its power again, can only use the forced air cooling.

plastic radiator the only drawback is that the unit price is more expensive, so it is not suitable for LED street light in this kind of large LED radiator, and only suitable for indoor small power LED lamps and lanterns.