The stringiness behavior during 180° peel testing was observed for crosslinked poly（ n-butyl acrylateacrylic acid）（ A） and poly（2-ethylhexyl acrylate-acrylic acid）（ B） with a constant crosslinker level. A fused quartz plate was used as adherend. The adhesive thickness and tensile rate were varied over the range from 15 to 60 µm and from 0.017 to 5 mm·s^-1, respectively. The peel strength increased with the increase of tensile rate and adhesive thickness. The peel strength for the specimen with the same adhesive thickness was B > A. The sawtooth-type peeling with a front frame was observed only for B with the adhesive thicknesses of 15 and 30 µm and with low tensile rate. In all other cases, no frame type was observed. The sawtooth length decreased with the increase of tensile rate and the decrease of adhesive thickness. It was B > A under the condition of the same tensile rate. There is good relation between the peel strength and the sawtooth length below the tensile rate of 0.5 mm·s^-1 when the result with the same tensile rate was compared.

A novel ultra-rapidly curable one-pack system was designed, where micro-coated isocyanate particle and liquid amine were combined. In this system, its main curing reaction is based on the nucleophilic polyaddition between diisocyanates and di- or tri-functional amines which results in the formation of urea linkage. When micro-coated 4,4ʼ-Diphenylmethane diisocyanate（ MDI） was used, the viscosity of mixture with amine hardly increased up to 5 weeks at 5℃ while it rose to 5 times after 5-day storage at 25℃. The measurement of gel-time on the hot plate revealed that this type of thermosetting resin can be cured in an extremely short time like 25 s at 40℃ or 0.5 s at 160℃. The bond strength of this resin measured by tensile shear test using aluminum plates broadly varied from 8 to 26 MPa depending on curing temperature. When cured at a lower temperature, it seemed very difficult for such rapidly curable isocyanate moiety to well-diffuse in the sea of amine in the heterogeneous system, which led to the low bond strength. On the other hand, it is considered that the cause that bond strength reached 25 MPa or more when cured at 200℃ is related to dissociation of urea linkage and subsequent complete diffusion of free isocyanate and amine.