In this study, the cool-off type thermosensitive pressure sensitive adhesives (PSAs) were prepared using vinyl acetate and acrylic monomer having long side chains for a dicing tape. Behenyl acrylate (BA), isobornyl acrylate (IBOA), and acrylic acid (AA) were dropped into vinyl acetate (VAc) monomer solution and underwent radical polymerization in varying composition ratios of monomers at the same time. Molecular weight and polydispersity of the prepared PSAs were measured by using gel permeation chromatography (GPC). After crosslinking with aluminum acetylacetonate (Alacac), adhesive properties were evaluated by peel strength and shear strength tests at 20, 40, 60 and 80 ℃. Thermal properties were evaluated by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). The suitability as a cool-off type thermosensitive PSAs was confirmed through the temperature dependent adhesion characteristics, and the reason why the temperature sensitivity was shown through the evaluation of the thermal properties was proved.

본 연구에서는 비닐아세테이트와 결정성 곁사슬을 포함하는 아크릴 단량체를 사용하여 다이싱 테이프에 적합한 쿨오프 타입 온도감응성 점착제를 제조하였다. 단량체로는 vinyl acetate(VAc), behenyl acrylate(BA), isobornyl acrylate(IBOA) 및 acrylic acid(AA)를 조성비를 변화시켜 사용하였고, 라디칼 개시제로 2,2'-azobisisobutyronitrile (AIBN)을 사용하여 적하중합법을 이용한 용액중합으로 점착제를 제조하였다. 합성된 점착제는 gel permeation chromatography(GPC)를 사용하여 분자량 및 다분산도를 측정하였고, aluminum acetylacetonate(Alacac)를 사용하여가교시킨 후 20, 40, 60 및 80 ℃에서 박리강도 시험과 전단력 시험을 통해 점착 특성을 평가하였으며, 시차 주사열량 분석(differential scanning calorimetry, DSC)과 열기계 분석(thermomechanical analysis, TMA)을 통하여 열적 특성을 평가하였다. 온도별 점착 특성을 통하여 쿨오프 타입 온도감응성 점착제로서의 적합성을 확인하였고, 열적 특성 평가를 통하여 이러한 온도감응성이 나타나는 이유를 증명하였다.

Keywords: pressure sensitive adhesive, vinyl acetate, side chain alkyl acrylate, thermosensitive, dicing tape