Abstract: An aqueous composition of an acrylic polymer to which a water soluble peroxide radical initiator has been added, said initiator being adapted to decompose at a temperature of from about 40.degree. C. to about 180.degree. C. and act on the polymer to crosslink the same. Using the aqueous composition, a water absorbent crosslinked polymer and a water absorbent polymer-coated article can be produced through simplified processes. The water absorbent crosslinked polymer exhibits excellent water absorbing and swelling properties so that it can be advantageously utilized for the production of wet absorbent articles such as disposable diaper, sanitary napkin or the like. The water absorbent polymer-coated article is excellent in water absorption properties and can be used safely for the purposes as mentioned above.

Abstract: A water absorbent fibrous product comprising a fibrous cellulosic material impregnated with a water absorbent acrylic polymer and a fibrous material, which is produced by a method in which an aqueous solution of a monomeric component comprising acrylic acid and a radical initiator is diffused in a fibrous cellulosic material and heated, followed by blending with a fibrous material. The fibrous product exhibits a high water absorbency, and finds applications as high-quality disposable diapers, sanitary napkins, surgical pads, surgical sheets, paper towels or the like.

Abstract: A water absorbent crosslinked polymer having at least 70% by weight of acrylic acid monomeric units, 60 to 90% of the carboxyl groups of which are in the form of an alkali metal salt, produced by a method in which a mixture comprised of acrylic acid, 60 to 90% of the carboxyl groups of which are in the form of an alkali metal salt, and a fibrous cellulosic material is heated in the presence of a radical initiator. The polymerization temperature can be effectively controlled by smooth evaporation of water. The cross-linked polymer can absorb such a large amount of water as several hundred times the weight of the polymer in an excellent absorption rate, and finds applications as, for example, a disposable diaper and a sanitary napkin.

Abstract: A control apparatus for a dental gas burner is disclosed which is capable of variably setting combustion time of the burner as desired. The control apparatus comprises a circuit for operating a solenoid valve provided at a fuel gas supply pipe, a circuit for igniting fuel gas ejected from a burner nozzle, a command circuit including a touch sensor and generating a pulse every touch with respect to the touch sensor, a combustion time setting circuit acting to count pulses of the command circuit to set combustion time corresponding to the number of counted pulses to open the valve during the time, and a timing circuit for supplying to the combustion time setting circuit a count signal required for counting the pulses.

Abstract: A method of purifying the contamination of a dental consultation room is disclosed. The purification method is characterized in that an anesthetic gas such as laughing gas and the dust generated by drilling a tooth or false tooth of the patient are changeably sucked either from a region close to the floor of the dental consultation room, or from outside the oral cavity of the patient, and are discharged outside the consultation room. Disclosed also is an apparatus for practicing the purification method.