Dual-Layer Absorbable Hemostatic Fabric

The patent employs a composite structure consisting of a nonwoven fabric layer and a woven or knitted fabric layer. The nonwoven layer provides immediate hemostatic effect through its absorbent properties, while the woven/knitted layer provides structural support and controlled degradation. This composite approach allows the material to maintain hemostatic effectiveness longer without interfering with biologically active agents, as the degradation rate is controlled by the composition and structure of the two different fabric layers.

The patent modifies the physical and chemical parameters of the hemostatic material by using different fiber compositions, densities, and layer configurations. By adjusting the density of each layer (first layer density different from second layer density) and the composition of fibers (natural vs synthetic, absorbable vs non-absorbable), the degradation rate and hemostatic effectiveness are optimized to work together rather than interfere with each other.

The hemostatic device is divided into two distinct fabric layers, each with specific functions. The first layer (nonwoven) is optimized for hemostatic activity and fluid absorption, while the second layer (woven or knitted) is optimized for structural reinforcement and tissue integration. This segmentation allows each layer to be manufactured using appropriate techniques for its specific function, then combined through needle punching to create a composite structure that achieves both hemostatic effectiveness and tissue reinforcement.

The patent transitions from a single-layer two-dimensional structure to a multi-layer three-dimensional composite structure. By stacking and needle-punching together two different fabric layers with different densities and properties, the device gains enhanced functional capabilities in the vertical dimension, providing both immediate hemostasis and sustained tissue reinforcement without complicating the manufacturing process.

The patent applies different density characteristics to different layers of the composite fabric. The first layer is designed with specific density optimized for fluid absorption and hemostatic action, while the second layer has different density optimized for mechanical strength and structural support. This local differentiation of density properties allows the overall device to achieve both high fluid absorption capacity and adequate mechanical strength simultaneously.

By combining two fabric layers with different density characteristics, the patent creates a composite material that exhibits properties superior to either layer alone. The less dense layer provides fluid absorption pathways and hemostatic activity, while the more dense layer provides structural integrity, resulting in a composite that achieves both mechanical strength and fluid absorption capacity.