In order to clarify the influences of backing and adhesive thicknesses on tack, thetack of acrylic block copolymer was measured using aprobe tack tester and polyethyleneterephthalate backing with various thickness in the range from 25 to 75μm. For this purpose, three model adhesives were prepared:polymethylmethacrylate-block-polybutylacrylate-block-polymethylmethacrylate triblock(A), polymethylmethacrylate-block-polybutylacrylate diblock added triblock(B) and polybutylacrylate oligomer added triblock(C). From the contact time dependence of tack, the slightly higher tack was obtained at the backing thickness of 38μm for A and at that of 50μm for B and C. The lowest tack was obtained at that of 25μm for all. The shape of stress-time curve measured by a probe tack test was strongly dependent on the backing thickness. Tack was lowest for glass as undeformable backing. There is most suitable backing thickness in each adhesive for improving tack dependent on the elastic modulus of adhesive. The adhesive thickness was varied in the range from 10 to 200μm. The tack rose with the increase in adhesive thickness for all adhesives. The tack rose rapidly below about 30μm thickness and gradually more than it with an increase of adhesive thickness.

It is important to control surface structures of polymeric materials and to clarify the formation process of polymer/polymer interfaces in order to understand adhesion. In this comprehensive paper, I summarize my recent work on how to make nano patterned surface materials, how to analyze asymmetric interdiffusion and an effect of chain topology on interdiffusion. As one of the molecular designs for surface functional materials, a block copolymer whose microphase-separated structure spontaneously appeared a the film surface due to the surface segretaion of the side chain groups was prepared. Short-time relaxation and/or mutual diffusion at interfaces of polystyrene/deuterated polystyrene bilayer films were measured by time-resolved neutron reflectivity measurements and analyzed based on the concentration profiles obtained by solving the diffusion equation. The comparis on of diffusion behavior of linear and cyclic polystyrenes reveals that hetopology strongly affects the molecular motion of the whole chain.

Bio-mass based curable resins having triethoxysilyl groups (bio-mass based silane terminated resin) were synthesized from castor oil (bio-mass polyol) and 3-isocyanatopropyltriethoxysilane. Dibutyltin dimethoxide (DBTDM) or boron trifluoride-monoethylamine complex (BF3-MEA) as a curing catalyst was blended with the bio-mass based silane terminated resin and 3-aminopropyltriethoxysilane to afford curable compositions. The cured products of the compositions were exposed to water at 80℃ and 85℃85%RH for various periods. The hydrolytic degradation was compared by IR spectroscopy. It was found that the both ester and urethane bonds in the curable compositions using BF3-MEA were more stable than those using DBTDM even after exposed to water at 80℃ and 85℃85% RH. BE3-MEA exhibited high catalytic activity, and the obtained material showed almost the same adhering properties as those cured by DBTDM. BE3-MEA is one of the most promising catalysts for bio-mass based silane terminated resin, and is widely applicable to adhesives, sealants, and coatings.