Provided are a prepreg including two or more fiber substrate layers and one or more resin composition layers, in which at least one of the one or more resin composition layers has a fiber substrate layer on each of both surfaces thereof, a printed circuit board using the prepreg and a method of producing the printed circuit board, and a semiconductor package.

A composite laminate structure includes one or more layers of prepreg and a thermoplastic polyurethane film layer on the surface of the one or more prepregs. A method of making a composite laminate structure including a thermoplastic polyurethane film is also provided.

In an example, a composite structure having a variable gage is described. The composite structure includes a first end having a first gage, a second end having a second gage, which is less than the first gage, a plurality of continuous plies, and a plurality of drop-off plies. Each continuous ply extends from the first end to the second end. Each drop-off ply includes a tip having a tapered shape. Each drop-off ply extends from the first end to a respective position of the tip of the drop-off ply between the first end and the second end. The tips of the plurality of drop-off plies are arranged in a monotonically-inward pattern.

In an example, a composite structure having a variable gage is described. The composite structure includes a first end having a first gage, a second end having a second gage, which is less than the first gage, a plurality of continuous plies, and a plurality of drop-off plies. Each continuous ply extends from the first end to the second end. Each drop-off ply includes a tip having a tapered shape. Each drop-off ply extends from the first end to a respective position of the tip of the drop-off ply between the first end and the second end. The plurality of drop-off plies are separated from each other by at least one of the plurality of continuous plies.

In an example, a composite structure having a variable gage is described. The composite structure includes a first end having a first gage, a second end having a second gage, which is less than the first gage, a plurality of continuous plies, and a plurality of drop-off plies. Each continuous ply extends from the first end to the second end. Each drop-off ply includes a tip having a blunt-end shape. Each drop-off ply extends from the first end to a respective position of the tip of the drop-off ply between the first end and the second end. The plurality of drop-off plies are separated from each other by at least one of the plurality of continuous plies.

Provided is a laminate that is excellent in flexibility and has a high bending strength. Also provided is a reinforcing sheet including such laminate. The laminate of the present invention is a laminate including an adhesive layer and a constraining layer, wherein the constraining layer includes an impregnated layer obtained by impregnating a multilayer base material, which is obtained by laminating a plurality of reinforcing fiber sheet-shaped products in each of which reinforcing fiber yarns are arranged in parallel and knitting the products with a stitching thread to integrate the products, with a thermosetting resin composition. The reinforcing sheet of the present invention includes the laminate of the present invention.

A resin composition that allows production of laminated sheets excellent in heat resistance and processability is disclosed. The resin composition comprises: a) a block copolymer, where the block copolymer comprises at least one polymer block comprising polymerized acyclic conjugated diene units, such as butadiene units, and at least one polymer block containing units like a conjugated cyclic diene such as 1,3-cyclohexadiene or monomer units characterized by unit Tg above 100 C., b) a curing initiator, and c) optionally diene-based polymer selected from a polybutadiene polymer and the copolymer of butadiene with styrene or other styrenic monomers, c) optional additives comprising but not limited to a multi-functional co-curable additive, a diene based rubber, a halogenated or non halogenated flame retardant, an inorganic or organic filler or fiber, an antioxidant, a adhesion promotor, a film forming

Curable prepregs possessing enhanced ability for the removal of gases from within prepregs and between prepreg plies in a prepreg layup prior to and/or during consolidation and curing. Each curable prepreg is a resin-impregnated, woven fabric that has been subjected to a treatment to create an array of openings in at least one major surface. Furthermore, the location of the openings is specific to the weave pattern of the fabric.

A ready to use surface veil and surface film integrated prepreg layer which is suitable to use in the production of lightweight structural parts/panels with class A surfaces includes a curable bottom base resin formulation including a curable bottom base resin, at least one first toughening agent, at least one accelerator, at least one curing agent and at least one hardener. The prepreg layer further includes a release paper that is coated with the curable bottom base resin formulation to obtained curable bottom base resin formulation coated release paper as a first resin film; a reinforcement fabric; an outer resin formulation including the outer resin which is the curable bottom base resin being 10% more viscous than the resin, at least one thermoplastic toughening agent, at least one accelerator, at least one curing agent and at least one hardener agent.

A prepreg comprising: carbon fibers; and a resin composition containing an epoxy resin having a biphenyl structure, a curing agent, and melamine cyanurate.