본 실험에서는 스크린 인쇄 및 그라비어 인쇄 등 direct printing에 사용가능한 UV 경화형 Ag paste를 제조하였다. Ag 분말은 표면이 극성이므로 분말끼리의 응집력이 강하고, 비극성인 UV경화형 수지와의 친화성이 좋지 못해, 분산성이 좋지 못한 paste를 얻을 수 있다. 따라서 본 실험에서는 Ag 분말 표면을 올레인산 또는 도데칸 티올로 코팅함으로써, Ag 분말 표면을 비극성화하여 UV 경화형 수지와의 친화성을 높이는 것으로 Ag 분말 일차 입경 수준의 paste 분산특성을 얻었다. 제조된 Ag paste의 레올로지 특성을 검토한 결과, 표면 처리된 Ag paste의 경우, 낮은 전단 영역에서 형성된 Ag 분말과 바인더 수지와의 응집구조에 의해 shear thinning 거동을 나타내며, 높은 저장 탄성율을 갖게 되었다. UV 경화한 Ag 도막의 전기적 특성을 측정한 결과, UV 경화가 진행될수록 Ag 분말사이의 접촉이 증가하여 비저항이 감소하였고, 1500mJ/㎠에서는 10-3Ω․㎝의 비저항을 갖는 Ag 도막을 얻을 수 있었다.

The phosphor and ITO(Indium Tin Oxide) films for video phone tube (VPT) were simply prepared by the screen printing and thermal transfer methods. The increasing order of thermal firing of acrylic binder for phosphor and ITO was M6003 < M6664 < A/A1919 < M5001 < M6701 and all mass of binders were perfectly decomposed at lower temperature than 400℃. After thermal firing of phosphor paste, the residual of binder on the surface of phosphor could not be found by SEM. Aerosil as thickner provides the thixotropy property for phosphor paste but decrease the brightness of phosphor screen as residual after thermal firing. Since the thixotropy of M5001 binder without aerosil was shown and the storage modulus of phosphor paste by increasing the angular frequency was not nearly changed and the decrease of the storage modulus of phosphor paste by increasing the strain was remarkably shown. It was possible to prepare the phosphor paste which was predominant in the plate separation and the reproduction of pattern after the screen printing. Since the addition of dispersing agent to improve the printing process decreases the electrical conductivity and light transmission of ITO film, it could be found to be necessary the development of binder for phosphor paste that decreases the amount of dispersing agent possibly and does not use the aerosil as additive.