Polyamide composite structures and processes for their preparation

Abstract

Disclosed herein are polyamide composite structures and processes for their preparation. The disclosed composite structures comprise a surface, having at least a portion made of a surface resin composition, and comprise a fibrous material being impregnated with a matrix resin composition. The surface resin composition is selected from polyamide compositions comprising a blend of (A) fully aliphatic polyamides having a melting point of less than 230° C., and (B) fully aliphatic polyamides having a melting point of at least 250° C., and wherein the matrix resin composition is independently selected from (B) or blends of (A) and (B).

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application claims the benefit of U.S. Provisional Application No. 61 / 408,166, filed Oct. 29, 2010, which is now pending, the entire disclosure of which is incorporated herein by reference; and U.S. Provisional Application Nos. 61 / 410,093, filed Nov. 4, 2010; 61 / 410,100, filed Nov. 4, 2010; 61 / 410,104, filed Nov. 4, 2010; and 61 / 410,108, filed Nov. 4, 2010, all of which are now pending, the entire disclosures of which are incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention relates to the field of composite structures and processes for their preparation, particularly it relates to the field of polyamide composite structures.BACKGROUND OF THE INVENTION[0003]With the aim of replacing metal parts for weight saving and cost reduction while having comparable or superior mechanical performance, structures based on composite materials comprising a polymer matrix containing a fibrous material have been de...

AI Technical Summary

Benefits of technology

[0010]There is a need for a thermoplastic polyamide composite structure that is easier to process in forming, shaping, or stamping, that exhibits good mechanical properties, especially flexural strength and having at least a portion of its surface allowing a good adhesion between its surface and an overmolding resin comprising a polyamide resin.

Problems solved by technology

Indeed, the time consuming chemical reaction of cross-linking for thermosetting resins (curing) is not required during the processing of thermoplastics.

Unfortunately, conventional thermoplastic polyamide resin compositions that are used to impregnate one or more fibrous layers and to overmold the one or more impregnated fibrous layers may require excessive heating during stamping, forming, or shaping, which may render their surfaces poor in appearance and in functionality, and / or may show poor adhesion between the overmolded polymer and the surface of the component comprising the fibrous material, i.e. the composite structure.

The poor adhesion may result in the formation of cracks at the interface of the overmolded composite structures leading to reduced mechanical properties, premature aging and problems related to delamination and deterioration of the article upon use and time.

In such case of weak adhesion, the interface between the composite structure and the overmolding resin will break first, rendering the overmolded composite structure weaker than either of its components.

Lower mechanical performance in these most demanding applications may impair the durability and safety of the article upon use and time.