Abstract: The present invention provides a novel phosphorus-containing phenolic resin. When the phosphorus-containing phenolic resin is used as an epoxy resin curing agent, the cured product thereof has various excellent properties such as excellent moisture resistance, low permittivity, a low dissipation factor, and excellent adhesion in addition to improved flame retardation. Specifically, the phosphorus-containing phenolic resin of the invention is represented by formula (1). The invention also provides a method for manufacturing the novel phosphorus-containing phenolic resin, a phenolic resin composition including the phosphorus-containing phenolic resin, an epoxy resin curing agent including the phenolic resin composition, an epoxy resin composition including the epoxy resin curing agent and an epoxy resin, a cured product obtained by curing the epoxy resin composition, and a copper-clad laminated plate obtained by using the epoxy resin composition as a matrix resin.

Abstract: The present invention provides a novel phosphorus-containing phenolic resin. When the phosphorus-containing phenolic resin is used as an epoxy resin curing agent, the cured product thereof has various excellent properties such as excellent moisture resistance, low permittivity, a low dissipation factor, and excellent adhesion in addition to improved flame retardation. Specifically, the phosphorus-containing phenolic resin of the invention is represented by formula (1). The invention also provides a method for manufacturing the novel phosphorus-containing phenolic resin, a phenolic resin composition including the phosphorus-containing phenolic resin, an epoxy resin curing agent including the phenolic resin composition, an epoxy resin composition including the epoxy resin curing agent and an epoxy resin, a cured product obtained by curing the epoxy resin composition, and a copper-clad laminated plate obtained by using the epoxy resin composition as a matrix resin.

Abstract: Provided is a process for preparing 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-C) compound, the process having steps of: reacting a liquid chlorinating agent and 9,10-dihydro-10-hydroxy-9-oxa 10-phosphaphenanthrene 10-oxide compound represented by formula (B) to form a mixture, the mixture comprises DOPO-C compound represented by formula (A) and an unreacted liquid chlorinating agent, separating the DOPO-C compound and the unreacted liquid chlorinating agent from the mixture to obtain the DOPO-C compound; wherein X1, X2, and X3 are each independently selected from the group consisting of hydrogen atom, hydroxyl group, cyano group, sulfonic acid group, sulfonate ester group represented by —SO3R1, halogen atom, alkoxy group represented by —OR2, acyclic hydrocarbon group having 1 to 8 carbon atoms, cyclic alkyl group having 3 to 8 carbon atoms, aryl group, heteroaryl group, and arylalkyl group, wherein R1 and R2 are each an acyclic hydrocarbon group having 1 to 8 carbon a