Abstract: A multistage plant culture method and apparatus for carrying out the method are disclosed. Culture beds constituted by rooting medium contained in culture containers and initially containing plant seedlings are moved, in order; from an uppermost level to a lowermost level after the plants have been grown at each level for a predetermined period. After cropping, the culture bed at the lowermost level is removed, and a new culture bed containing seedlings is placed at the vacant uppermost level. This sequence is repeated. The culture containers have a predetermined length and are supported on a plurality of support means arranged vertically at different heights. A culture container lift unit includes culture container holding means capable of movement towards or away from the culture containers, and also capable of holding the containers and moving them up or down to facilitate their movement between the different levels.

Abstract: A process for producing flame-resistant foam resins is disclosed. The flame-resistant foam resin is produced by reacting an organic polyisocyanate with urea.

Abstract: A method of producing polyurea foams is disclosed. The polyurea foam is produced by reacting an organic polyisocyanate with water in the presence of urea or by reacting a crude tolylene diisocyanate or a mixture of crude tolylene diisocyanate and crude diphenylmethane diisocyanate as an organic polyisocyanate with water in the presence of an amine catalyst, a silicone surfactant and, if necessary, a tin catalyst.