Fiber mat formation for structural applications
A process for forming a mat containing a fiber filler including providing one or more sources of extended length fiber; feeding the one or more sources of extended length fiber simultaneously to an automated cutting machine to produce chopped tow fibers; separating the chopped fiber tow into individual chopped fibers that form a fiber filler; coating the fiber filler with a binder; depositing the fiber filler on a first sheet of thermoplastic; covering the fiber filler with a second sheet of thermoplastic to form a stack; and moving the stack to a treatment chamber to form a fiber mat.
1. A process of forming a mat containing a fiber filler comprising: providing one or more sources of extended length fiber; feeding the one or more sources of extended length cylindrical fiber tow simultaneously to an automated cutting machine to produce lengths of cylindrical bundles of chopped fiber tow; randomizing and filamentizing the lengths of cylindrical bundles of chopped fiber tow into individual chopped fibers by tumbling using a vortex formed within a tube to form a fiber filler; coating the fiber filler with a binder; depositing the fiber filler on a first sheet of thermoplastic; covering the fiber filler with a second sheet of thermoplastic to form a stack; and moving the stack to a treatment chamber to form a fiber mat.
2. The process of claim 1 wherein said one or more sources of extended length fiber are glass, carbon, polyimides, polyesters, polyaramides, polyamides, a mixed tow of any of the aforementioned, or a combination thereof.
3. The process of claim 1 wherein the vortex formed within the tube is accomplished with deionized air.
4. The process of claim 1 wherein a plurality of types of extended length fiber are supplied to provide a defined ratio by weight in the fiber mat.
5. The process of claim 4 wherein the defined ratio of two or more fibers thermoplastic fiber from 25% to 80% by weight, glass fiber from 0% to 75% by weight, carbon fiber from 0% to 75% by weight, and a binder in the range of 0% to 30% by weight where are least one of glass fiber, carbon fiber, and binder are present in a total amount of 20% to 75% by weight.
6. The process of claim 1 further comprising adding Curie fillers.
7. The process of claim 1 further comprising exposing the chopped fibers to a plasma or flame treatment prior to said covering.
8. The process of claim 7 wherein the exposing step is within a fluidized bed reactor.
9. The process of claim 7 wherein the plasma is cold plasma.
10. The process of claim 7 wherein the plasma is hot plasma.
11. The process of claim 1 further comprising adding additional layers of the fiber filler between additional sheets of thermoplastic.
12. The process of claim 1 wherein the treatment chamber has a set of heated rollers maintained at or above a softening temperature of the thermoplastic sheets and the stack is moved at a speed past the set of heated rollers to fuse the stack.