The prepreg includes a first resin layer and a second resin layer disposed on both surfaces of the first resin layer. The first resin layer is a half-cured product of a first resin composition that includes a glass cloth impregnated with the first resin composition and contains no hexagonal boron nitride. The second resin layer is a half-cured product of a second resin composition containing hexagonal boron nitride. The glass cloth has a warp and weft weave density of 54 pieces/25 mm or more. The hexagonal boron nitride has an average particle size ranging from 10 m to 30 m. The hexagonal boron nitride is contained in an amount ranging from 20 parts by mass to 40 parts by mass relative to 100 parts by mass of a residual component other than the hexagonal boron nitride in the second resin composition.

The present invention relates to a phosphazene compound and a composite metal laminate. The phosphazene compound with a partial structure of carboxylic esters has a structure as shown in Formula (I). The present invention obtains a phosphazene compound with a partial structure of carboxylic esters using an M group having specific components. The cured products of the phosphazene compound have good flame retardancy, heat resistance, mechanical properties, flame retardancy, and low dielectric constant, and are a low dielectric flame retardant material having great economic properties and being environmental friendly.

The present invention relates to a phosphazene compound and a prepreg and a composite metal laminate. The phosphazene compound has a structure as shown in Formula (I). The present invention obtains a phosphazene compound using an M group having specific components. The composite metal laminates prepared by the epoxy resin composition comprising the phosphazene compound have low dielectric properties, good heat resistance and mechanical properties and is a low dielectric material also having great economic properties and being environmental friendly.

Provided is a prepreg including a fiber substrate having a thickness of 40 ?m or more impregnated with a thermosetting resin composition, the prepreg having in the fiber substrate an impregnated region and a non-impregnated region with the thermosetting resin composition, having a surface waviness (Wa) of 5.0 ?m or less. Also provided are a laminate, a metal-clad laminate, a printed wiring board, and a semiconductor package, which are obtained by using the prepreg, a method of producing the prepreg, and a method of producing the metal-clad laminate.

Pre-impregnated composite material (prepreg) that can be cured/molded to form aerospace composite parts. The prepreg includes carbon reinforcing fibers and an uncured resin matrix. The resin matrix includes an epoxy component that is a combination of a hydrocarbon epoxy novolac resin and a trifunctional epoxy resin and a tetrafunctional epoxy resin. The resin matrix includes polyethersulfone as a toughening agent and a thermoplastic particle component that includes a mixture of polyamide particles and polyimide particles.

Provided are: an FRP precursor capable of providing a metal-clad laminate having small surface waviness and reduced number of a light spot, even if thickness of a metal foil is 40 ?m or less; a laminated plate including the FRP precursor; a metal-clad laminate having a metal foil on the laminated plate; a printed circuit board having a circuit pattern formed on the metal-clad laminate; a semiconductor package including the printed circuit board; and methods for producing them. The FRP precursor has the surface waviness of 12 ?m or less on both surfaces thereof.

The thermosetting resin composition according to an embodiment of the present invention contains a component (A) which is a novolac vinyl ester resin having a hydroxyl group and an ethylenically unsaturated group in the molecule, a component (B) which is an ethylenically unsaturated monomer, and a component (D) which is a polyisocyanate compound, wherein the component (A) has a hydroxyl value of 30-150 mgKOH/g, and the mole number of the hydroxyl group with respect to the mole number of the ethylenically unsaturated group per gram of the component (A) ((the amount of the hydroxyl group [mol/g])/(the amount of the ethylenically unsaturated group [mol/g])) is 0.1-0.8.

The carbon fiber forming raw material is a carbon fiber forming raw material (Z) as a prepreg including sizing agent-coated carbon fibers and a thermosetting resin or a carbon fiber forming raw material (Y) as a forming material that includes sizing agent-coated carbon fibers and has a woven fabric form or a braid form. The sizing agent includes components (A) and (B). The component (A) is an epoxy compound having two or more epoxy groups or two or more types of functional groups. The component (B) is one or more compounds selected from the group consisting of a tertiary amine compound, a tertiary amine salt, a quaternary ammonium salt, a quaternary phosphonium salt, and a phosphine compound. The component (B) is contained in an amount of 0.1 to 25 parts by mass relative to 100 parts by mass of the component (A).

Pre-impregnated composite material (prepreg) that can be cured/molded to form aerospace composite parts. The prepreg includes carbon reinforcing fibers and an uncured resin matrix. The resin matrix includes an epoxy component that is a combination of a hydrocarbon epoxy novolac resin and a trifunctional epoxy resin and optionally a tetrafunctional epoxy resin. The resin matrix includes polyethersulfone as a toughening agent and a thermoplastic particle component.

A resin composition is comprised of an epoxy resin comprised of a solid epoxy resin and a liquid polyurethane toughener that is dissolved in the epoxy resin and, upon curing of the liquid epoxy resin, the liquid polyurethane toughener phase separates into particles having a particle size of 50 nm to 2 micrometers, an epoxy hardener; and an epoxy soluble latent catalyst. The resin composition provides a more homogeneous infusion of the resin into a fibrous material for forming a prepreg and ultimately an epoxy fiber reinforced composition with improved toughness without sacrificing speed of impregnation or uniformity of the epoxy matrix within the composite.