The reliability of the adhesive joint, that is, the probability that the joint functions properly, depends on the degree of durability against stresses such as temperature, humidity, mechanical stress, sunlight, wind and rain, the degree of joint strength and confficient of variation, and the redundancy of the joint system such as spot welding and riveting used together or not. Here, we will explain the method for promptly calculating the failure probability of adhesive joints after use for a certain period and the safety factor（ average strength of the joint / average mechanical stress） required to secure the predetermined failure probability based on a stress-strength model using the EXCEL calculation sheet for the standard normal distribution function（ NORMSDIST） and its inverse（ NORMSINV）.

Following to a previous work, this article reviews the photo cationic polymerization initiators（ or the photo acid generators） including monoarylsulfonium, diaryliodonium, and ferrocenium salts available in the market as latent curing agents for epoxy resin. Monoarylsulfonium salt can polymerize epoxy resin cationically both by heat and by light although the photo-activation ability is generally poor compared to triarylsulfonium salt. Diaryliodonium salt is one of the major photo initiators comparable to triarylsulfonium salt, and also has the heat curing ability of epoxy resin. Various substituents, such as alkyl or alkoxy groups with different chain lengths, have been incorporated into the benzene ring of diaryliodonium salt in order to avoid the benzene emission, to improve the solubility with epoxy resin, and to reduce the toxicity originated from Iodonium. As a result, more than a dozen of improved diaryliodonium salt products are on the market. Ferrocenium salt（ or Fe-arena complex） can polymerize epoxy resin under the visible light although the applied market is still small. Taking CAS registration number as identification of the commercially available product, the article mainly focuses on reviewing the chemical structures and properties of above-mentioned photo cationic initiators together with the photo-activation mechanism of initiator and the cationic polymerization mechanism of epoxy resin.

There are chemisorbed and physisorbed silane coupling agent（ SCA） molecules in the treated layer on inor ganic surface. The former is chemicaly bonded and the later is adsorbed by van der Waals force to the surface. Increasing of chemisorption by the increase of molecular weight of SCA was investigated. For the SCA with amino group, the chemisorbed molecules were larger for amino-ethyl aminooctyltrimethoxysilane as high molecular weight type than for 3-aminopropyltrietoxysilanene as normal type. For the SCA with hydrocarbon chain, the chemisorption was lower for both low molecular weight type and decyltrimethoxysilane（ DTMS） as high molecular weight type. For the SCA with fluorocarbon chain, the chemisorption was lower for the low mo lecular weight type, whereas it increased significantly by heating for 1H,1H,2H,2H-perfluorodecyltriethoxysi lane（ F17DTES） as high molecular weight type. The wide angle X-ray diffraction analysis for F17DTES treated silica particles showed that the fluorocarbon chain forms lamellar structure. On the other hand, there was no indication of ordered structure for DTMS-treated system. This seems to influence on the difference of chemisorption for both treated systems.

The compatibility of blend systems of styrene-isoprene block copolymer（ SIS） and tackifier resins with different solubility parameters（ δ） was verified by AFM observation and SAXS measurement. We discussed “Viscoelastic windows”, which is the mechanical property of the pressure sensitive adhesive bulk, and its effect on the final adhesive performance. For the resins compatible with the polyisoprene（ PI） phase, C5/C9 petroleum resin, which has a slightly higher δ value than C5 petroleum resin, reduces the polystyrene（ PS） domains that acts as a physical cross linking points between SISs. So it was suggested that the cohesive strength of the system decreased, which led to an increase in tack and adhesion. On the other hand, coumarone-indene resin and α-methylstyrene resin, which are compatible with PS phases with high δ value, it suggested that there are preferentially compatible with PS phases, and some are slightly localized in the surrounding PI phases. The tack and peel strength is increased by adding coumarone indene resin with high δ value to C5 petroleum resin, but it decreases conversely when coumarone indene resin is added to C5/C9 petroleum resin. This is thought to be due to the relative decrease in the compatibility of the coumarone indene resin to the PS phases due to the decrease in the PS domains by the addition of C5/C9 petroleum resin, which led to a decrease in adhesive properties.