reinforced fiber composites

Abstract

The present invention relates to a reinforced fiber composite material, which is a reinforced fiber composite material comprising discontinuous reinforcing fibers comprising at least aggregates of discontinuous reinforcing fibers comprising at least 5 wt. % or more discontinuous reinforcing fiber aggregates (A), for the discontinuous reinforcing fiber aggregates (A), when the discontinuous reinforcing fiber aggregates are two-dimensionally projected, the orientation direction of the discontinuous reinforcing fibers The widest widening portion in which the width of the discontinuous reinforcing fiber aggregate in the intersecting direction is widened to the widest exists at positions other than both ends of the discontinuous reinforcing fiber aggregate, and the width-thickness ratio of the widest widening portion is (Width of Discontinuous Reinforcing Fiber Aggregate / Discontinuous Reinforcing Fiber Aggregate Thickness) is 1.3 times or more the width-thickness ratio of at least one end portion of the discontinuous reinforcing fiber aggregate. The present invention can provide a reinforced fiber composite material capable of achieving both high fluidity and high mechanical properties during molding at a high level, and exhibiting excellent fluidity and two-dimensional isotropy especially during flow molding.

Description

technical field [0001] The present invention relates to a reinforced fiber composite material comprising discontinuous reinforcing fibers and a matrix resin, and particularly relates to a two-dimensional each A reinforced fiber composite material with excellent isotropy and uniformity, and which can achieve both high fluidity and high mechanical properties when molded products are used. Background technique [0002] Fiber-reinforced composite materials consisting of reinforcing fibers and matrix resin are used in the manufacture of various molded products due to their high mechanical properties, and the demand in various fields is increasing year by year. [0003] As a method of molding reinforced fiber composite materials with high functional properties, the most commonly practiced method is the following autoclave molding method: a semi-cured intermediate base material called a prepreg (which is impregnated with a matrix resin The matrix resin is cured by heat and pressur...

AI Technical Summary

Problems solved by technology

However, as described in the above-mentioned Patent Documents 1 and 2, when the carbon fiber bundle is divided in the width direction, the number of contact points between the carbon fibers in the obtained carbon fiber composite material increases and the fluidity deteriorates.

In addition, the width and thickness of the carbon fiber mat are based on the premise that the cross-sectional shape of the fiber aggregate is a substantially uniform columnar body formed of a rectangular shape or an ellipse with respect to the longitudinal direction of the fiber aggregate (fiber length direction). For the carbon fiber felt, the thinner the fiber thickness, the better the mechanical properties of the carbon fiber composite molded products manufactured using it, but the fluidity during molding is low and the formability is poor

This is because: since the carbon fibers as reinforcing fibers are sufficiently dispersed, the stress is not easily concentrated, and the reinforcing effect of the carbon fibers can be fully exhibited, but on the other hand, the carbon fibers intersect with each other to restrict mutual movement, making it difficult to move

[0007] In addition, for a carbon fiber mat with a wide fiber width, the contact area between the fibers tends to increase, and the mutual movement is restricted to make it difficult to move. Therefore, it is difficult to exhibit fluidity during molding, and the formability is poor.

In addition, the thicker the fiber thickness, the better the fluidity during molding of the carbon fiber composite molded article manufactured using it, but the followability to the mold of the molded article with a complex shape such as ribs and a thin thickness is poor, and the mechanical properties are low.

This is because, since the carbon fiber bundles are thick, the carbon fibers do not form a network structure (network). Therefore, although they are easy to move at the initial stage of flow, when molding a molded body with a complex shape such as ribs and a thin thickness, the carbon fiber bundles are not connected to each other. Intertwining hinders the flow of the matrix resin and tends to concentrate stress on the ends of the carbon fiber bundles

[0008] In addition, Patent Document 3 discloses a carbon fiber composite material obtained by opening a wire bundle, cutting it, and impregnating it with a thermosetting resin, and its production method. However, similar to the above-mentioned Patent Documents 1 and 2, the width and thickness of the carbon fiber are determined by The cross-section of the fiber aggregate in the longitudinal direction (fiber length direction) is a substantially uniform columnar body with a substantially rectangular shape. For a carbon fiber sheet with a wide fiber width, the thicker the fiber thickness, the greater the fiber thickness. The better the fluidity of the carbon fiber composite molded product, the better the mold followability for the molded body with complex shapes such as ribs and thin thickness, and the mechanical properties are low.

In addition, the thinner the fiber thickness, the better the mechanical properties of the carbon fiber composite molded article manufactured using it, but the fluidity is poor

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