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.

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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.

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.

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.

Methods and apparatus for curing a substrate or polymer using variable microwave frequency are provided herein. In some embodiments, a method of curing a substrate or polymer using variable microwave frequency includes: contacting a substrate or polymer with a plurality of predetermined discontinuous microwave energy bandwidths or a plurality of predetermined discontinuous microwave energy frequencies to cure the substrate or polymer.

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.

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.

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.

The present invention relates to a process for chemically degrading materials containing benzoxazine resin, in particular benzoxazine resins, benzoxazine resin pre-polymers and benzoxazine resin-containing plastics, that enables a high quality recycling process for used up benzoxazine resin-containing materials, in particular the separation of composite materials, such as duromer-based fiber composite plastics containing a benzoxazine resin matrix, and reuse of the benzoxazine-containing materials.

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.