Abstract: Provided is a purified lactic acid-glycolic acid copolymer, preferably in the form of powder, having a reduced content of dimers such as residual lactide and glycolide that can be produced by a simple industrial process without the use of any high-shear special device. Further provided is a high-purity lactic acid-glycolic acid copolymer which has small amounts of dimers such as residual lactide and glycolide and small amounts of a low-molecular weight lactic acid-glycolic acid copolymer or a salt thereof and which has a small ratio of weight average molecular weight to number average molecular weight (Mw/Mn). The copolymer can be produced in accordance with a defined process.

Abstract: Provided is a purified lactic acid-glycolic acid copolymer, preferably in the form of powder, having a reduced content of dimers such as residual lactide and glycolide that can be produced by a simple industrial process without the use of any high-shear special device. Further provided is a high-purity lactic acid-glycolic acid copolymer which has small amounts of dimers such as residual lactide and glycolide and small amounts of a low-molecular weight lactic acid-glycolic acid copolymer or a salt thereof and which has a small ratio of weight average molecular weight to number average molecular weight (Mw/Mn). The copolymer can be produced in accordance with a defined process.

Abstract: The problem of the invention is to provide a novel biodegradable polymer without water solubility (hygroscopicity), but with moldability and excellent water disintegratability and biodegradability, a production method thereof, a molded product thereof and applications thereof. The biodegradable polymer of the invention is a biodegradable polymer having one or more imine bonds within a molecule, characterized in that the imine bond constitutes part of a main chain structure of the biodegradable polymer. The biodegradable polymer preferably comprises a biodegradable unit and an imine unit having one or more imine bonds and has a chemical structure, in which the biodegradable units are linked by the imine unit.

Abstract: The problem of the invention is to provide a novel biodegradable polymer without water solubility (hygroscopicity), but with moldability and excellent water disintegratability and biodegradability, a production method thereof, a molded product thereof and applications thereof. The biodegradable polymer of the invention is a biodegradable polymer having one or more imine bonds within a molecule, characterized in that the imine bond constitutes part of a main chain structure of the biodegradable polymer. The biodegradable polymer preferably comprises a biodegradable unit and an imine unit having one or more imine bonds and has a chemical structure, in which the biodegradable units are linked by the imine unit.

Abstract: An epoxy resin composition comprising an epoxy resin (A), a curing agent (B) and a curing accelerator (C), wherein the curing agent (B) is a phenol compound having two or more hydroxyl functional groups or a compound obtained by esterification of the phenol compound or a mixture of these compounds, and the curing accelerator (C) is a salt of a phosphazenium compound represented by a formula (I): (wherein R1s each represent a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms or an aryl or aralkyl group having 6 to 10 carbon atoms and may be all the same or different from one another; and Z? represents a halogen anion, hydroxy anion, alkoxy anion, aryloxy anion or carboxy anion).

Abstract: There are disclosed a process for producing an organic compound in the presence of a particular substituted triarylphosphine compound, particularly, a process for producing an oxyalkylene derivative at a high yield using the above compound which is very active and easy to handle, by reacting an organic epoxy compound with a carboxylic acid ester, a carboxylic acid anhydride, a sulfonic acid ester or a carbonic acid ester, and an epoxy resin composition using a particular substituted triarylphosphine compound as a curing accelerator, a cured material of the composition and a semiconductor device using the composition.

Abstract: An epoxy resin composition comprising an epoxy resin (A), a curing agent (B) and a curing accelerator (C), wherein the curing agent (B) is a phenol compound having two or more functional groups or a compound obtained by esterification of the phenol compound or a mixture of these compounds, and the curing accelerator (C) is a salt of a phosphazenium compound represented by a formula (I): 1

Abstract: A preparation process of phenol aralkyl resin from phenol compound and aralkyl compound by controlling the temperature of reaction mass in the range of 70 to 240.degree. C. and simultaneously controlling the temperature of vapor phase potion and vapor-liquid interface portion of manufacturing equipment so as to keep the wall surface of the vapor phase portion and vapor-liquid interface portion in a wet state. The invention can prevent scale adhesion to the interior of manufacturing equipment, remarkably reduce the number of washing and scale removing procedures on the manufacturing equipment, and enable efficient manufacture of phenol aralkyl resin. When the phenol aralkyl resin obtained is used for a molding material, molded articles having excellent heat resistance and high reliability can be provided.

Abstract: An allyletherificated phenol aralkyl resin is obtained through the reaction of a phenol aralkyl resin with an allyl halide in the presence of a base in an organic solvent at room temperature to 100.degree. C. and changed into an allylated phenol aralkyl resin at 160.degree.-250.degree. C. through Claisen rearrangement. The two resins are low in melt viscosity. Epoxy resin compositions containing the allylated phenol aralkyl resin as the curing agent give cured products being excellent in heat and moisture resistances.

Abstract: A phenolic resin composition comprises a mixture of 100 parts by weight of a phenol aralkyl resin and 5 to 60 parts by weight of a novolak type phenolic resin having a content of binuclear components of not more than 10% by area, and a content of trinuclear components of not less than 50% by area and a sum content of tri- and tetra-nuclear components of 75% by area based on the total novolak phenolic resin except for the binuclear components, and an epoxy-cured product obtained by curing an epoxy resin while using the phenolic resin composition as set forth in claim 1 as a curing agent. The phenolic resin composition has a low viscosity and, when it is used as a curing agent for epoxy resins, the resulting epoxy-cured product has a low water absorption rate, is excellent in resistance to moisture and has a high glass transition temperature as compared with the cured product obtained using a novolak type phenolic resin as a curing agent.

Abstract: When recording information, a write switching current of a write signal is directed through a coil of a magnetic head, whereby the information corresponding to the write signal is to be recorded on a magnetic recording medium. Hence, a back electromotive voltage is inevitably produced at the coil of the magnetic head. Based on the level of this back electromotive voltage, the quality of the magnetic head can be detected. In this case, by use of a synchronizing circuit, the detected timing of the back electromotive voltage is synchronized with a switching timing of the write switching current. Due to this synchronizing circuit, the back electromotive voltage is detected only at the switching timing of the write switching current, whereby it becomes possible to detect the back electromotive voltage, regardless of noise. Thus, it is possible to detect the quality of the magnetic head with accuracy.