Abstract: Disclosed is a flame-retardant epoxy resin composition characterized by containing (A) an epoxy resin containing 0.5-10 equivalent/kg of oxazolidone rings, (B) an epoxy group-containing phosphazene compound, (C) at least one compound selected from the group consisting of phosphates, condensed phosphates, quinone derivatives of phosphine compounds, and polyphenylene ethers, and (D) at least one curing agent selected from the group consisting of guanidine derivatives, phenol novolacs, bisphenol A novolacs, cresol novolacs and naphthol novolacs.

Abstract: To provide an epoxy resin composition that can afford a printed wiring board excellent in heat resistance, adhesiveness, prepreg storage stability, and insulation reliability. An epoxy resin composition containing (A) an oxazolidone ring-containing epoxy resin, (B) a novolac-type epoxy resin, (C) a guanidine derivative, and (D) an imidazole as components, wherein the component (A) contains an isocyanuric ring as well as an oxazolidone ring and, the IR absorbance ratio of the isocyanuric ring to the oxazolidone ring is not less than 0.01 and not more than 0.1, the weight ratio of the component (A) to the component (B) is 5:95 to 95:5, the content of the component (C) and the content of the component (D) are 0.01 to 5 parts by weight and not more than 0.

Abstract: Disclosed is a flame-retardant epoxy resin composition characterized by containing (A) an epoxy resin containing 0.5-10 equivalent/kg of oxazolidone rings, (B) an epoxy group-containing phosphazene compound, (C) at least one compound selected from the group consisting of phosphates, condensed phosphates, quinone derivatives of phosphine compounds, and polyphenylene ethers, and (D) at least one curing agent selected from the group consisting of guanidine derivatives, phenol novolacs, bisphenol A novolacs, cresol novolacs and naphthol novolacs.

Abstract: The roll gap control system for a calender having first and second rolls (18, 19) rolling a raw material (B) includes a load measuring unit (11) for detecting a rolling load change between the first and second rolls (18, 19), a roll shaft position adjusting device (41) for increasing/decreasing a roll gap and a controller (46) for computing a roll gap change (.DELTA.h) based on the rolling load change (.DELTA.P) and for activating the roll shaft position adjusting device (41) to compensate for the roll gap change (.DELTA.h). A spring constant (k) of first and second rolls (18, 19) and mechanical members (24, 25, 28) supporting these rolls of the calender is calculated, and the rolling load change (.DELTA.P) is divided by the spring constant (k). The quotient (.DELTA.P/k) is the roll gap change (.DELTA.h).