A hexagonal boron nitride powder having an average longer diameter (L) of primary particles in the hexagonal boron nitride powder of more than 10.0 μm and 30.0 μm or less, an average thickness (D) of the primary particles in the hexagonal boron nitride powder of 1.0 μm or more, a ratio of the average longer diameter (L) to the average thickness (D), [L/D], of 3.0 or more and 5.0 or less, and a content of primary particles having a ratio of a longer diameter (1) to a thickness (d), [l/d], of 3.0 or more and 5.0 or less of 25% or more, a method for producing the hexagonal boron nitride powder, and a resin composition and a resin sheet each containing the hexagonal boron nitride powder.

A composite reinforcing bar is formed by providing a reinforcing material supply of fiber strands ravings; a resin supply bath, and a puller for pulling the resin-impregnated reinforcing material through the resin bath. The material is wound on a holder, while the resin remains unset, rotated about its axis on a drive system so that the material is wrapped around a plurality of guides at spaced positions around the axis such that the fed length of the body is wrapped from one bar to the next to form bent portions of the body wrapped partly around each guide and straight portions between the guides. The guide surfaces are shaped by a machining, blasting or similar process to form projections and recesses which retain a roughness on the outside surface of the reinforcing bar during the curing action while supported on the surface. This arrangement can be used with an optional sand coating to prevent the sand particles from being compressed into the resin or body.

The present disclosure is directed to articles that include one or more coated fiber(s) (i.e., fiber(s) with a cured coating disposed thereon), where the coating includes a matrix of crosslinked polymers and optionally a colorant (e.g., pigment particles or dye or both). The cured coating is a product of crosslinking a coating composition including uncrosslinked polymers (e.g., a dispersion of uncrosslinked polymers in a carrier, wherein the uncrosslinked polymers are crosslinked to form the matrix of crosslinked polymers). The present disclosure is also directed to articles including the coated fibers, methods of forming the coated fibers and articles, and methods of making articles including the coated fibers.

The present disclosure generally relates to systems and methods for composites, including short-fiber films and other composites. In certain aspects, composites comprising a plurality of aligned fibers are provided. The fibers may be substantially aligned, and may be present at relatively high densities within the composite. For example, the composite may include substantially aligned carbon fibers embedded within a thermoplastic substrate. The composites may be prepared, in some aspects, by dispersing fibers by neutralizing the electrostatic interactions between the fibers, for example using aqueous liquids containing the fibers that are able to neutralize the electrostatic interactions that typically occur between the fibers. The liquids may be applied to a substrate, and the fibers may be aligned using techniques such as shear flow and/or magnetism. Other aspects are generally directed to methods of using such composites, kits including such composites, or the like.

An object of the present invention is to provide a carbon fiber which exhibits excellent strength development rate when used in a composite material. The present invention that solves the problems is a carbon fiber which simultaneously satisfies the following formulae (1) and (2):

Lc/d≤3  (1)

TS×d×Lc>6.0×10.sup.5  (2) wherein: Lc is an X-ray crystallite size (Å), d is a filament diameter (μm), and TS is a strand tensile strength (MPa).

Provided is a useful improvement in a CF-SMC manufacturing technique comprising an SMC manufacturing method using a continuous carbon fiber bundle having a filament number of NK and partially split into n sub-bundles in advance. In the SMC manufacturing method according to the present invention, a fragmentation processing using a fragmentation processing apparatus (A) below is performed on chopped carbon fiber bundles before being deposited on a carrier film. The fragmentation processing apparatus (A) comprises a first pin roller and a second pin roller, each of which has a rotation axis parallel to a rotation axis direction of the rotary cutter. The first pin roller is rotationally driven such that its pins move downward from above on its side facing the second pin roller, and the second pin roller is rotationally driven such that its pins move downward from above on its side facing the first pin roller.

Glass compositions suitable for fiber forming having low levels of Li.sub.2O and glass fibers having high-modulus are disclosed. The glass composition may include SiO.sub.2 from about 59 to about 63 weight percent, Al.sub.2O.sub.3 from about 13.7 to about 16 weight percent, CaO from about 14 to about 16.5 weight percent, MgO from about 6 to about 8.5 weight percent, Fe.sub.2O.sub.3 less than 1 weight percent, and TiO.sub.2 less than 1 weight percent. In some cases, the composition may be substantially free of Li.sub.2O. In some cases, the composition may include Li.sub.2O up to 0.5 weight percent. In some cases, RE.sub.2O.sub.3 may be present in the composition in an amount up to 1.5 weight percent. The glass compositions can be used to form glass fibers which can be incorporated into a variety of other fiber glass products (e.g., strands, rovings, fabrics, etc.) and incorporated into various composites.

The present invention relates to a thermosetting material for use in a 3D printing process comprising: a) at least one epoxy resin A, b) at least one elastomer-modified epoxy resin B, c) at least one resin C with a dynamic viscosity of below 4 Pas at 150° C., d) at least one of a curing agent D capable of reacting with A, B and optionally C, e) and optionally additional compounds,
wherein the glass transition temperature of the uncured material is at least 30° C., preferably at least 40° C. as measured with DSC at a heating rate of 20° C./min.

The invention further relates to a method of producing a cured 3D thermoset object and the use of the above-mentioned thermosetting material in a 3D printing process.

There is provided a method of manufacturing an openly and highly porous thermoset foam, the method comprising the steps of mixing a thermosetting resin and crystals to form a mixture; applying pressure to the mixture to expel excess thermosetting resin, thereby producing a network of crystals touching each other with the thermosetting resin filling the interstices between the crystals of said network; curing the thermosetting resin in the mixture under pressure to produce a cured material; and contacting the cured material with a solvent for the crystals, thereby leaching the crystals out of the cured material, thereby obtaining said openly and highly porous thermoset foam. There is also provided a thermoset foam made of a thermoset and having a porosity of at least about 70%, wherein more than about 75% of the pores in the foam are connected to a neighboring pore.

The present invention relates to a resin composition including an acrylic polymer (A) and a thermosetting resin (B), wherein a phase separation structure of a first phase containing the acrylic polymer (A) and a second phase containing the thermosetting resin (B) is formed, and an average domain size of the second phase is 20 μm or less.