Thermally Conductive Plastics Enter China's LED Lighting Market
In an exclusive interview with Sina, Tang Jihua, General Manager of RenJie Plastic Materials Co., Ltd., noted that the company began R&D on high thermally conductive plastics for LED lighting products as early as 2008. In 2014, as the LED lighting market boomed, RenJie — six years after starting the work — officially launched the thermally conductive plastic products it had spent years developing. In Tang's view, thermally conductive plastic has a higher thermal emissivity than aluminum, giving it an excellent ability to dissipate heat from the surface. Although its heat-conduction capability is inferior to metal, this can be improved by incorporating aluminum parts into the heat-sink fin design — and heat-sink fins made from thermally conductive plastic are more cost-competitive than aluminum.
1. How the Company Entered the LED Market: One Research Paper and 10 Years in High-End Engineering Plastics
Asked how the company entered the LED market, Tang Jihua explained that at the time he came across a research paper discussing the developmental potential of applying thermally conductive plastics to heat-sink fins for LED lighting products. The company decided to draw on its 10 years of technical expertise in the high-end engineering plastics field to develop a thermally conductive plastic capable of entering the LED lighting market.
Through continuous experimentation, RenJie Plastic Materials Co., Ltd. has developed more than 1,000 formulations. The first consideration was the material's cooling effect, then cost, followed by the color and strength performance of the plastic. The company also ran regrind (remelt-blending) tests on the thermally conductive plastic, which showed that recycled thermally conductive plastic differs little from virgin material — effectively reducing customers' material purchase costs.
2. Cost Advantage: The Best Material Choice as LED Lighting Demand Scales Up
"Cost" is precisely the biggest reason RenJie is confident that thermally conductive plastic can replace aluminum as the mainstream material for heat-sink fins. Tang Jihua was frank: "Those of us in materials understand the importance of cost only too well. No matter how good or how beautiful the product is, it is useless — it must meet the customer's cost requirements."
On material cost: the thermally conductive plastic sold by RenJie Plastic Materials Co., Ltd. costs about 30 RMB per kilogram, 15%–30% lower than the cost of aluminum fins.
On processing cost: the labor and processing hours that customers spend must also be factored in. Heat-sink fins made of aluminum must go through surface polishing, grinding, drilling and anodizing. By contrast, thermally conductive plastic is produced by injection molding. What is most notable at this stage is that RenJie Plastic Materials Co., Ltd. has developed a thermally conductive plastic raw material with low abrasion on equipment — so that, overall, customers see a clear and measurable reduction in system cost.
Thermally conductive plastic vs. aluminum: heat-sink fins compared
| Item | Thermally conductive plastic | Aluminum heat-sink fins |
|---|---|---|
| Material price | About 30 RMB/kg | Baseline (plastic is 15%–30% lower) |
| Processing steps | Injection molding, single shot | Surface polishing, grinding, drilling, anodizing |
| Equipment abrasion | Low-abrasion material | — |
| Heat conduction | Inferior to metal; can be improved with aluminum inserts | Better |
| Thermal emissivity | Higher than aluminum; excellent surface heat dissipation | Baseline |
| Recyclability | Regrind performs much like virgin material | — |
| Safety | Lower surface temperature; no burns when changing bulbs | High surface temperature |
3. Thermal Performance: 8 W and 10 W LED Bulbs Stay Below 80 °C
Beyond material and manufacturing costs, thermal performance is the customer's biggest consideration when choosing a heat-sink fin. Although the heat-conduction capability of thermally conductive plastic is inferior to metal, laboratory temperature tests at RenJie showed that when RenJie's thermally conductive plastic is used in 8 W and 10 W LED bulbs, temperatures remain below 80 °C — meeting the general standards of the LED lighting industry.
The thermal emissivity of thermally conductive plastic is far higher than that of metal, so heat can be quickly released from the surface. When users change a bulb, they are far less likely to be burned by the high temperature of the heat-sink fin — a clear safety advantage for consumers.
Thermally Conductive Plastics Enter China's LED Lighting Heat-Dissipation Market
4. FAQ
Q1: Thermally conductive plastic or aluminum — which is better for heat-sink fins? A: Thermally conductive plastic conducts heat less well than metal, but its thermal emissivity is higher than aluminum's, giving excellent surface heat dissipation. It also costs 15%–30% less than aluminum fins with fewer processing steps, which improves overall system cost. Where higher heat conduction is required, aluminum inserts can be added to the fin design.
Q2: How much does thermally conductive plastic cost per kilogram? A: In this interview Tang Jihua gave a price of about 30 RMB per kilogram (2014 figure), 15%–30% cheaper than aluminum fins. Current pricing should be confirmed by quotation.
Q3: Can thermally conductive plastic be recycled? A: Yes. RenJie ran regrind tests on the thermally conductive plastic, which showed that recycled material differs little from virgin material, effectively reducing customers' material purchase costs.
Q4: What temperature can thermally conductive plastic achieve in LED bulbs? A: In laboratory temperature tests, RenJie's thermally conductive plastic kept 8 W and 10 W LED bulb temperatures below 80 °C, meeting the general standards of the LED lighting industry.
Q5: What processing steps are required for aluminum heat-sink fins? A: Aluminum heat-sink fins must go through surface polishing, grinding, drilling and anodizing; thermally conductive plastic is produced by injection molding and causes low abrasion to equipment.