The invention relates to a composition containing a novolak and water. In one embodiment, a composition is provided comprising novolak and water with the percentage of ortho linkages of the phenol rings of the novolak is greater than that of para linkages, the novolak having a phenolic compound and an aldehyde molar ratio of from 1:0.2 to 1:0.45 and the composition having from 2% to 20% by weight of water based on the weight of the sum of the novolak and the water.

The invention relates to a composition containing a novolak and water. In one embodiment, a composition is provided comprising novolak and water with the percentage of ortho linkages of the phenol rings of the novolak is greater than that of para linkages, the novolak having a phenolic compound and an aldehyde molar ratio of from 1:0.2 to 1:0.45 and the composition having from 2% to 20% by weight of water based on the weight of the sum of the novolak and the water.

An object is to provide a resin composition having a high permittivity and a low dissipation factor, and having excellent heat resistance and moisture absorption and heat resistance, and suitably used for producing an insulation layer of a printed wiring board, and a prepreg, a resin sheet, a laminate, a metal foil-clad laminate, and a printed wiring board obtainable by using the resin composition. The resin composition of the present invention contains (A) a surface coated titanium oxide in which a mass reduction rate in heating from 30 C. to 300 C. at a heating rate of 10 C./min is 0.5 mass % or less, and (B) a thermosetting compound.

An object is to provide a resin composition having a high permittivity and a low dissipation factor, and having excellent heat resistance and moisture absorption and heat resistance, and suitably used for producing an insulation layer of a printed wiring board, and a prepreg, a resin sheet, a laminate, a metal foil-clad laminate, and a printed wiring board obtainable by using the resin composition. The resin composition of the present invention contains (A) a surface coated titanium oxide in which a mass reduction rate in heating from 30 C. to 300 C. at a heating rate of 10 C./min is 0.5 mass % or less, and (B) a thermosetting compound.

There is provided a resin composition from a mixture including: (a) 60-90 weight % of at least one thermosetting resin; and (b) 10-40 weight % of at least one aryl ether resin. The resin composition can be used in electronics applications.

A curable resin that can have excellent heat resistance (a high glass transition temperature) and dielectric properties (low dielectric properties), the curable resin composition, and its cured product. Specifically, a curable resin (A) contains both a structure represented by General Formula (1) below and a structure represented by General Formula (2) below. (In the afomentioned General Formula (1), the details of the substituents and the number of the substituents are as described in the present specification.) (In the afomentioned General Formula (2), the details of the substituents and the number of the substituents are as described in the present specification.)

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A curable resin that can have excellent heat resistance (a high glass transition temperature) and dielectric properties (low dielectric properties), the curable resin composition, and its cured product. Specifically, a curable resin (A) contains both a structure represented by General Formula (1) below and a structure represented by General Formula (2) below. (In the afomentioned General Formula (1), the details of the substituents and the number of the substituents are as described in the present specification.) (In the afomentioned General Formula (2), the details of the substituents and the number of the substituents are as described in the present specification.)

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