According to one aspect, a glass-free pre-impregnated material includes a polybenzimidazole (PBI) sheet and a partially cured resin encapsulating the PBI sheet. According to another aspect, a process of forming a glass-free pre-impregnated material includes encapsulating a PBI sheet within a resin and partially curing the resin to form the glass-free pre-impregnated material. According to yet another aspect, a printed circuit board comprises a glass-free dielectric layer that includes a PBI sheet encapsulated within a cured resin.

The present invention relates to photocurable compositions, comprising (A1) a N-vinyloxazolidinone of formula (I), wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently of each other a hydrogen atom or an organic group having not more than 10 carbon atoms, (A2) optionally one, or more second reactive diluents, (B) one, or more oligomers, and (C) a photoinitiator (C), wherein the amount of component (A1) is 5 to 70% by weight based on the amount of components (A1), (A2) and (B), wherein the viscosity of said photocurable composition is in the range 10 to 3000 mPa.Math.s, preferably 10 to 1500 mPa.Math.s at 30? C. The compositions, from which cured three-dimensional shaped articles having balanced mechanical properties combining stiffness with high toughness can be made, are particularly suitable for the production of three-dimensional articles by stereolithography and photopolymer jetting. ##STR00001##

A method of forming a three-dimensional object is carried out by: (a) providing a cyanate ester dual cure resin; (b) forming a three-dimensional intermediate from said resin, where said intermediate has the shape of, or a shape to be imparted to, said three-dimensional object, and where said resin is solidified by exposure to light; (c) optionally washing the three-dimensional intermediate, and then (d) heating and/or microwave irradiating said three-dimensional intermediate sufficiently to further cure said resin and form said three-dimensional object. Compositions useful for carrying out the method, and products made from the method, are also described.

Provided is an active-energy-ray-curable composition including: a monomer (A) having a hydrogen-bonding capacity; and a compound (B) having a hydrogen-bonding capacity and containing straight-chain alkyl containing 4 or more carbon atoms, wherein a cured product of the active-energy-ray-curable composition is a solid that exhibits a compressive stress of 2 kPa or higher in response to compression by 1%, and wherein the active-energy-ray-curable composition is a liquid in an environment of 60 degrees C.

The invention relates to a process for breaking down materials containing benzoxazine resin that is characterized in that the material containing benzoxazine resin is reacted by aminolysis with an agent containing at least one reactive NH.sub.2 and/or NH group. The process enables the material containing benzoxazine resin to be reused; after the breaking-down, volatile products are removed, preferably under reduced pressure and/or at elevated temperature, and the material is mixed with one or more substances that react with the resultant breakdown products to form a polymer network.

The invention relates to a hollow article with rigid walls (18 98), surrounding an enclosed space (19, . . . , 99) that occupies the interior of the hollow article (10, . . . , 90), made of a primary plastic base material (1) in which there is provided a secondary plastic material (2), consisting of a polymer, characterized in that this secondary polymer (2) is formed by a first component (A), being a cyclic diisocyanate as a cyclic compound, with an aromatic or optionally an aliphatic structure, and by at least one additional component (B), wherein this secondary plastic material (2) forms a barrier (12, . . . , 92) in the hollow article (10, . . . , 90), and method for producing thereof.

Modeling material formulations usable in additive manufacturing of a denture structure, and additive manufacturing methods employing same are provided. Kits comprising the modeling material formulation, optionally in combination with a support material formulation, are also provided.

Provided are an electron beam curable resin composition including polymethylpentene, and a crosslinking agent, in which the crosslinking agent has a saturated or unsaturated ring structure, at least one atom among atoms forming at least one ring is bonded to any allylic substituent of an allyl group, a methallyl group, an allyl group through a linking group, and a methallyl group through a linking group, and a molecular weight is 1,000 or less, a resin frame for reflectors using the resin composition, a reflector, and a molding method using the resin composition.

Provided are an electron beam curable resin composition including polymethylpentene, and a crosslinking agent, in which the crosslinking agent has a saturated or unsaturated ring structure, at least one atom among atoms forming at least one ring is bonded to any allylic substituent of an allyl group, a methallyl group, an allyl group through a linking group, and a methallyl group through a linking group, and a molecular weight is 1,000 or less, a resin frame for reflectors using the resin composition, a reflector, and a molding method using the resin composition.

Provided are an electron beam curable resin composition including polymethylpentene, and a crosslinking agent, in which the crosslinking agent has a saturated or unsaturated ring structure, at least one atom among atoms forming at least one ring is bonded to any allylic substituent of an allyl group, a methallyl group, an allyl group through a linking group, and a methallyl group through a linking group, and a molecular weight is 1,000 or less, a resin frame for reflectors using the resin composition, a reflector, and a molding method using the resin composition.