The interaction of PbCrO4 and linseed oil modified alkyd resin were studied by thermal analytical method. The glyphthal resin and linseed oil were selected as the samples from the chemical composition of linseed oil modified alkyd resin and were analyzed by thermal analytical method. The samples of three types were analyzed by thermal glavimetric analysis and differential thermal analysis. The samples of the first types were organic materials only. The samples of the second types were just a mixture of PbCrO4 and organic materials. The samples of third types were the stored the samples of the second types for 3,000 hr. in air. For the all samples of second and third types, PbCrO4 had catalytical action and promoted the thermal oxidative degradation. The thermal oxidative degradation of the third types of the samples were very differenced from that of the first types of the samples. The third types of linseed oil and linseed oil modified alkyd resin with PbCrO4 had vigorously given oxidative degradation from 300°C to 500°C.
Catalytic activity for dehydration and dehydrogenation of isopropyl alcohol over the pigments was measured by a microcatalytic reactor to determine the acidic sites and/or the basic sites on the pigments. The pigments were classified into four groups by the reaction products of isopropyl alcohol as follows; Group 1. The type of pigments which mainly produces propylene. Group 2. What mainly produces acetone. Group 3. What forms both acetone and propylene. Group 4. What does not decompose isopropyl alcohol. In order to find the structure of active sites, organic compounds such as pyridine and acetic acid were added to the pigments, and the decomposition of isopropyl alcohol was measured. After the comparison of the activity with that before the addition, the reaction mechanisms were discussed. From these results, the decomposition process can be classified into the following three types. 1. Only acidic sites act to the dehydration. 2. Although acidic sites mainly act, basic sites are also concerned with dehydration. 3. Although basic sites mainly act, acidic sites are also concerned with dehydrogenation.
The authors are studying a method of predicting the service life of coated steel sheet by a test as short period as possible. The prediction of the service life of steel sheet coated with polyester resin paint by the method under study by the authors was already reported in Report [I]. The present report deals with the possibility of application of the method under consideration on the service life prediction of steel sheet coated with silicone polyester resin paint of different resin group as used for exterior building materials. The result of our study shows that the service life prediction according our method is also applicable to the silicone polyester resin coated galvanized steel sheet. Also, it was found that the silicone polyester resin coated galvanized steel sheet is superior to polyester resin coated galvanized steel sheet in wear resistance and corrosion resistance in that the former is smaller in the change of such physical properties as hardness and water absorption rate of the coated film rather than in the appearance change such as decrease in gloss and change in color.