Composite fiber having a high surface area and flexibility and method for manufacturing the same, and substrate containing the composite fiber and method for manufacturing the same

A method for manufacturing a non-woven substrate, comprising:

• (a) providing a first component, wherein the first component has a first viscosity;
• (b) melting the first component, transferring the melted first component to a first spin beam, and setting a first temperature;
• (c) providing a second component, wherein the second component has a second viscosity, and the second viscosity is greater than the first viscosity;
• (d) melting the second component, transferring the melted second component to a second spin beam, and setting a second temperature, wherein the second temperature is lower than the first temperature;
• (e) co-extruding the first component and the second component, to form a composite fiber, wherein the first component is in an amount of 50 wt % to 95 wt %, based on the total weight of the composite fiber, the second component is in an amount of 5 wt % to 50 wt %, based on the total weight of the composite fiber, the cross section of the composite fiber is in a substantially circular shape and has a maximum diameter and a circumference, the first component of the composite fiber has a central portion and a plurality of extension portions extending from the central portion to the circumference, a maximum length of the central portion is less than three quarters of the maximum diameter, the second component of the composite fiber has a plurality of outer portions, each outer portion is in a fan shape and is disposed between two extension portions, and the extension portions and the outer portions are alternately distributed in the circumference;
• (f) forming a fiber web with a plurality of composite fibers;
• and
• (g) separating the first component and the second component in the composite fibers, to form a non-woven substrate.