Abstract:
A process for the preparation of a fiber reinforced composite article comprising the steps of a) providing a mold, comprising an upper die (11) and a lower die (12), the lower die (12) having a molding surface and vertically extending side walls (14), the upper die (11) having a complementary molding surface and vertically extending side walls (13) substantially aligned with the side walls of the lower die, so that the upper die vertically moves into the lower die to form a cavity (17) in a partially and completely closed position of the mold, wherein the cavity (17) in a partially closed position is sealed vacuum-tight by at least one seal (15) placed around the vertically extending walls of the upper die (11), or the lower die (12), horizontally to the moving direction of the upper die (11), and wherein the at least one seal (15) also works as a resin retention seal which prevents the resin from leaking, b) applying a thermosetting resin composition onto a fibre reinforcement, and placing the thus treated fibre reinforcement into the lower die of the mold (12), or c) placing a fibre reinforcement into the lower die of the mold (12), and applying a thermosetting resin composition onto the fibre reinforcement d) moving the upper die (11) into the lower die (12) and partially closing the mold, e) evacuating the mold in the partially closed position by means of a vacuum outlet to a pressure of from 0.1 to 100 mbar, f) completely closing the mold and exerting an hydraulic pressure of from 2 to 100 bar onto the resin treated reinforcement to complete impregnation of the fibre reinforcement, g) curing the resin impregnated reinforcement, h) demolding the cured composite article, facilitates manufacturing of composite articles with reduced cycle times, said composite articles exhibit high fibre content, low void content and excellent visual and mechanical properties, and can be used for the construction of mass transportation vehicles, in particular, in automotive and aerospace industry.
Abstract:
L'invention concerne une composition comprenant au moins un polymère polyamide issu d'au moins un prépolymère polyamide réactif comprenant au moins un allongeur de chaîne (PA 1 -AII 1 -PA 1 ), ledit polymère polyamide étant préparé à une température T 1 supérieure ou égale à la température T f ou Tg dudit polymère et présentant une masse moléculaire moyenne Mn,, caractérisée en ce que ladite composition présente une viscosité à l'état fondu modulable en fonction de la température à laquelle ladite composition est soumise, ladite température étant comprise de T 2 à T 3 , T 2 et T 3 étant supérieures à T i , et ladite viscosité à l'état fondu n 2 ou n'3 observée respectivement à la température T 2 ou T 3 étant inférieure à la viscosité à l'état fondu η 2 ou η 3 dudit polymère polyamide, dépourvu d'allongeur de chaîne et de même masse moléculaire moyenne Mn i (PA,) observée à la même température T 2 ou T 3 , et avec : ladite composition comprenant ou étant constituée de un ou plusieurs polyamides, y compris copolyamides statistiques ou séquencés qui comprennent des motifs amides de formule A/(B) r /(C) s différents.
Abstract:
A fiber reinforced polymer composition is disclosed. A set of processing parameters is also disclosed which is suitable to process the fiber reinforced polymer composition to manufacture a void-free composite article at a rapid rate and having a similar performance as if it was cured in an autoclave. The composite manufacturing technology utilizes rapid heating/cooling rates and material technologies enabling not only absorption of rapid heat transfers and a suitable balance between cure kinetics and flow characteristics, but also excellent thermal and mechanical performances of the composite article, equivalent or exceeding the properties of an autoclave cured article. The process is applicable to fiber reinforced polymer parts currently made from an autoclave, but which demand faster production rates.