Abstract: A bifunctional phenylene ether oligomer of the formula (1), obtained by oxidation polymerization of a bivalent phenol of the formula (2) and a monovalent phenol of the formula (3), HO—YaO—X—OY—ObH ??(1) HO—X—OH ??(2) Y—OH ??(3) wherein —X— is represented by the formula (2?), and Y—O— is represented by the formula (3), R2, R3, R4, R8, R9, R10 and R11 in the formula (2?) and the formula (3?) being required not to be a hydrogen atom, and its use.

Abstract: A bifunctional phenylene ether oligomer of the formula (1), obtained by oxidation polymerization of a bivalent phenol of the formula (2) and a monovalent phenol of the formula (3), H?O—Y?a?O—X—O??Y—O?bH ??(1) HO—X—OH ??(2) Y—OH ??(3) wherein —X— is represented by the formula (2?), and Y—O— is represented by the formula (3), R2, R3, R4, R8, R9, R10 and R11 in the formula (2?) and the formula (3?) being required not to be a hydrogen atom, and its use.

Abstract: A bifunctional phenylene ether oligomer containing monophenylene and biphenylene moieties can be rendered thermosetting by reacting the terminal phenolic hydroxyl groups with a) a cyanogen halide to introduce terminal cyanate groups, b) a halogenated glycidyl to form terminal epoxy groups, or c) an allyl halide to produce allylic terminal groups. The epoxy-terminated phenylene ether oligomer can be further reacted acrylic and/or methacrylic acid to yield an epoxy di(meth)acrylate which can be further modified with a carboxylic acid or anhydride to obtain and acid-modified epoxy di(meth)acrylate.

Abstract: A bifunctional phenylene ether oligomer of the formula (1), obtained by oxidation polymerization of a bivalent phenol of the formula (2) and a monovalent phenol of the formula (3), wherein —X— is represented by the formula (2?), and Y—O— is represented by the formula (3), R2, R3, R4, R8, R9, R10 and R11 in the formula (2?) and the formula (3?) being required not to be a hydrogen atom, and its use.

Abstract: A bifunctional phenylene ether oligomer of the formula (1), obtained by oxidation polymerization of a bivalent phenol of the formula (2) and a monovalent phenol of the formula (3), wherein —X— is represented by the formula (2?), and Y—O— is represented by the formula (3), R2, R3, R4, R8, R9, R10 and R11 in the formula (2?) and the formula (3?) being required not to be a hydrogen atom, and its use.

Abstract: A bifunctional phenylene ether oligomer of the formula (1), obtained by oxidation polymerization of a bivalent phenol of the formula (2) and a monovalent phenol of the formula (3), (wherein —X— is represented by the formula (2?), and Y—O— is represented by the formula (3), R2, R3, R4, R8, R9, R10 and R11 in the formula (2?) and the formula (3?) being required not to be a hydrogen atom, and its use.

Abstract: A bifunctional phenylene ether oligomer of the formula (1), obtained by oxidation polymerization of a bivalent phenol of the formula (2) and a monovalent phenol of the formula (3), HO—YaO—X—OY—ObH??(1) HO—X—OH??(2) Y—OH??(3) wherein —X— is represented by the formula (2?), and Y—O— is represented by the formula (3), R2, R3, R4, R8, R9, R10 and R11 in the formula (2?) and the formula (3?) being required not to be a hydrogen atom, and its use.

Abstract: A bifunctional phenylene ether oligomer of the formula (1), obtained by oxidation polymerization of a bivalent phenol of the formula (2) and a monovalent phenol of the formula (3), 1

Abstract: A bifunctional phenylene ether oligomer of the formula (1), obtained by oxidation polymerization of abivalent phenol of the formula (2) and a monovalent phenol of the formula (3), H&Brketopenst;O—Y&Brketclosest;a&Parenopenst;O—X—O&Parenclosest;&Brketopenst;Y—O&Brketclosest;bH  (1) HO—X—OH  (2) Y—OH  (3) wherein —X— is represented by the formula (2′),  and Y—O— is represented by the formula (3), R2, R3, R4, R8, R9, R10 and R11 in the formula (2′) and the formula (3′) being required not to be a hydrogen atom, and its use.

Abstract: A bifunctional phenylene ether oligomer of the formula (1), obtained by oxidation polymerization of abivalent phenol of the formula (2) and a monovalent phenol of the formula (3),

Abstract: An electrical laminate having an ability to absorb or shield ultraviolet rays having wavelength of 300-420 nm which comprises (i) at least one thermosetting resin-impregnated substrate, (ii) said substrate and a metal foil or (iii) said substrate, a metal foil and an adhesive layer for the metal foil comprising a thermosetting resin, characterized in that the thermosetting resin constituting part or all of said substrates or constituting said adhesive layer contains 0.2-6.0% by weight of a light absorber (A) on the basis of weight of the thermosetting resin, said light absorber is (a) an alkylthioxantone or a mixture of (a) said alkylthioxantone and (b) an ultraviolet rays-absorber.

Abstract: A method for preparing a thin copper foil-clad substrate for the manufacture therefrom of circuit boards, which comprises subjecting a copper foil-clad circuit board substrate comprising an electrically insulating support having provided on one or both sides thereof a copper foil having an average thickness of 12 .mu.m or more to etching with an etching solution for copper, the etching being performed such that the whole surface of the copper foil is etched at a predetermined etching rate selected from the range of from 0.01 to 0.3 .mu.m/sec, thereby to reduce the thickness of the copper foil on at least one side of the insulating support to 10 to 80% of its original thickness, and the variation of the thickness of the copper foil remaining after the etching is within .+-.2.0 .mu.m on the basis of a desired thickness.