Terpineol based SOLVENTS
FOR ORGANIC CARRIERS OF ELECTRONIC PASTES
Organic carrier is the basic material of electronic pastes. They are identified as volatility carrier and non-volatility carrier. As the volatility performance, this specification influence rheology and initial adhesive attraction to electronic pastes.
There are some typical carriers be used in formulas, include Ethyl Cellulose (EC), Nitrated Cellulose (NC), PVA, PAA, polyurethane emulsion (PUE), PVB, PAM, etc. Binders usually use Pine Oil, Turpentine, EC-terpineol and Acrylic Resins. In these binders, EC-terpineol is the main stabilizer-solvent system. (Shiyong Luo, 2007) The viscosity of electronic pastes was controlled by Ethyl Cellulose on mass fraction. As tests resulted that when the EC is about 5%, the formula works well.
A high-speed volatilization will increase the viscosity, reduce rheology that screen is easy blocking. A too slow performance will delay the painting process, and inks would not easy drying that produces rejected. If the volatility focuses on a range of temperature, the film chaps and produces air hole after the paste sinter. (Shiyong Luo, 2006)
So how to choose the right solvent is the key to improve the performance of electronic pastes.
Some research results that the contents of the organic carrier in electronic paste formulas will affect the cut force. ( Weiping Gan, 2007) When the contents of carrier increasing, the cut force of sinter film will reduce due to the shrinkage ratio. If formulas can improve this shrinkage ratio, it can improve the compatibility in the film. But if organic carrier contents too low, the paste will blocks screen.
In the EC-terpineol stabilizer-solvent system, we can improve the volatilization feature by adding Turpentine, Terpineol, DBAC or DBP. There is a referrible proportion is DBAC by 28.5%, Terpineol by 57%, DBP by 9.5% and Ethyl Cellulose by 5%. (Shiyong Luo, 2006)
The mass loss of Ethyl Cellulose was 91.66% at 325°C to 375°C. Carrier was volatilized at the temperature range of 150°C to 200°C, the mass loss was 93.88%.
INNOVATION & MARKET FORECAST
- Reduce manufacture cost, use BME replace NME.
- Improve performance.
- Eco-friendly, limited to use BBP, DBP, and unleaded formulas will are the industry standard.