Polyphenylene ether oligomer compound, derivatives thereof and use thereof

#The present invention relates to a bifunctional phenylene ether oligomer compound having a thermosetting functional group at each terminal, an epoxy resin containing the above oligomer compound and a use thereof. More specifically, it relates to a sealing epoxy resin composition for sealing an electric part, an epoxy resin composition for laminates, a laminate, a printed wiring board, a curable resin composition and a photosensitive resin composition. The resins and resin compositions of the present invention are used in electronics fields in which a low dielectric constant, a low dielectric loss tangent and high toughness are required and also used for various uses such as coating, bonding and molding.

#As for materials for use in an electric or electronic field, as the speed of transmission signal increases, a low dielectric constant which decreases a time delay and a low dielectric loss tangent which decreases a loss are desired for utilizing a high-frequency wave (gigahertz band). Further, higher toughness is also desired in order to inhibit the occurrence of microcracks which are thought to be generated by thermal shock and secure high reliability. For the above demands, there are carried out attempts of incorporation of engineering plastic, such as polyphenylene ether (PPE), as a modified polymer having several properties. However, since a thermoplastic resin is directly incorporated into a thermosetting resin, problems remain with regard to the compatibility between the resins and molding processability.

#For improving the compatibility, a method of improving compatibility by blending PPE with a different resin as a compatibilizing agent is discussed and the pseudo IPN structuralization of PPE and a cyanate resin is also discussed (JP-A-11-21452, etc.). However, the problems of molding processability and heat resistance have not been solved yet. Further, a method of converting a high molecular PPE into a low molecular compound is discussed for improving moldability. For example, there is known a method in which a high molecular PPE and polyphenols are redistributed in the presence of a radical catalyst (JP-A-9-291148, etc.). Further, for obtaining toughness, there is known a method in which a bivalent phenol and a monovalent phenol are subjected to oxidation polymerization to obtain a thermosetting resin having a cyanate ester group (JP-B-8-011747).

#The present invention will be explained concretely with reference to Examples, while the present invention shall not be specially limited to these Examples. In Examples, “part” stands for “part by weight”. A number average molecular weight and a weight average molecular weight were measured according to the gel permeation chromatography (GPC) method. Dielectric constant and dielectric loss tangent were obtained by a cavity resonant oscillation method.

#Production Process of Bifunctional PPE Oligomer Compound

#A longitudinally long reactor having a volume of 2 liters and equipped with a stirrer, a thermometer, an air-introducing tube and baffleplates was charged with 2.7 g (0.012 mol) of CuBr2, 70.7 g (0.55 mol) of di-n-butylamine and 600 g of toluene. The components were stirred at a reaction temperature of 40° C. A mixed solution(bivalent phenol of the formula (7): monovalent phenol of the formula (8) in a molar ratio=1:2) obtained by dissolving 59.6 g (0.21 mol) of a bivalent phenol 4,4′-(1-methylethylidene)bis(2,6-dimehtylphenol) and 50.4 g (0.41 mol) of 2,6-dimehtylphenol in 600 g of methanol was dropwise added to the reactor over 120 minutes while carrying out bubbling with 2L/min of air. After the completion of the addition, stirring was carried out for 30 minutes while continuing the bubbling with 2L/min of air. A disodium dihydrogen ethylenediamine tetraacetate aqueous solution was added to the stirred mixture to terminate the reaction. Then, washing was carried out with 1N hydrochloric acid aqueous solution and then washing was carried out with pure water. The thus-obtained solution was concentrated by an evaporator, to remove the methanol. Then, toluene was added to obtain 70% toluene solution. Part of the above toluene solution was further concentrated and then dried under reduced pressure, to obtain a powder. The powder had a number average molecular weight of 690, a weight average molecular weight of 970 and a hydroxyl group equivalent of 360.