2-Hydroxy-4'-methoxychalcone (HMC), a synthetic anthocyanin dye, has the same molecular skeleton as plant pigments and is promising as a safe and environmentally friendly photochromic material. With the objective of using the HMC dye under dry conditions, a composite of Al containing mesoporous silica (Al-MPS) and HMC dye was prepared, and its photochromic properties were investigated. The composite of Al-free MPS had a vivid yellow appearance ; the color disappeared within seven days on storage in darkness at 313 K and 95% RH. Its color strength recovered to 50% of the initial value on UV-A irradiation, demonstrating the coloring-discoloring process. Incorporation of Al into MPS increased the quantity of HMC dye adsorbed onto it; however, the discoloring process from the FV+ form (yellow) to the t-C form (non-color) of the dye occurred with some difficulty.
Structural adhesives adopted for replacing spot welding in automotive industry are usually applied to the steel substrates contaminated with various oils such as ship-out oil, stamping or drawing oils. This paper describes the effects of epoxy adhesive composition and surface structure of the oily galvanized steel substrates on the adhesive bonding. Interfacial analysis by XPS and FTIR has disclosed that the preferential adsorption of amino curing agents at the interface plays an important role and that the bond durability of hot-dipped galvanized steel has decreased due to the surface segregation of both lead and aluminum which stimulates intergranular corrosion of zinc during hot water immersion.
There are many laws relating to chemicals. The paints are regulated by the laws relating to chemicals, because they are made from chemicals such as pigments and solvents. We introduce the overview of the laws which people who are concerned with paint should know beforehand at the least.
A variety of organic UV-absorbers and inorganic UV-shielders are used for sunscreen cosmetics these days. As inorganic UV-shielders, ultra-fine metal oxide powders such as titanium dioxide and zinc oxide are commonly used. Both titanium dioxide and zinc oxide have been manufactured and commercially used for years and have become typical raw materials for sunscreen cosmetics. It is widely known that ultra-fine titanium dioxide is used in order to shield UV-B which causes sunburn, while zinc oxide is used to shield UV-A which causes suntan. In the present paper the background to the different usages of the two oxides is explained by considering the difference in their optical properties. In addition, the special features and design concept of ultra-fine particles, which differ from pigment products, are explained by describing their basic properties, production process and photo-catalytic activity.