Patent Application
20240175173
Disclosed is a method of a reinforcement fiber and low melt material such as a thermoplastic polymer and polyester, resulting in a matrix having a low melt and configured for weaving into a fabric without the need for reliance on sheets, that can provide high performance properties in an end product that can include, lighter weight, increased flex, improved impact resistance, and any combination thereof.
The material, including a thermoplastic material and reinforcement material, of the present invention can include the combination of a first fiber and low melt fiber that can exhibit any of a high modulus, high tenacity. The material can include a unique crystalline structure including in the multifilament polyolefin fiber, including a reinforcement fiber, and can be combined with a resin or matrix material. The manufacturing process can generally include extruding a polymeric melt, including a polyolefin, at a relatively high throughput and low spin line tension and quenching the filaments in a liquid bath prior to drawing the fiber bundle at a relatively high draw ratio, for example greater than 10, in some embodiments. The filaments can be combined with a low melt fiber such as one with a melting point below 140° C. and process using one or more of automated fiber placement, thermoforming, collaborative composition manufacturing and robotic layup.
One problem with the current state of the art is that other thermoplastic materials need a manufacturing process where a fiber plus a liquid resin or a matrix system is used. It would be advantageous to have a thermoplastic that used two or more fibers.
A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying Figures in which:
The current invention is a thermoplastic that can include polymer resins that soften when exposed to heat and hardens when cooled. The invention can be thermoplastic so that it can be recycled. In one embodiment, the first material can be a reinforcing fiber with properties that are taken from the group consisting of multi-filament olefin yarn, density 0.84/cc, hydrophobic, resistant to wear, ductile, durable, low dielectric properties, colored, low elongation, low creep, highly crystalline, recyclable and any combination thereof. When combined the resulting thermoplastic can be formed into a matrix material without having to rely upon a resin or matrix material for creation.
The use of the reinforcement material, including thermoplastics, can provide for the resulting fiber combination of a reinforcement fiber and second fiber, much as a low melt polyester to provide for properties that include the ability to reduce part fabrication timeline, low moisture uptake, toughness and damage resistance, no refrigeration or autoclave needed for large structure fabrication, ability to re-form parts, low void content, simplified manufacturing processes and methods, less wastage, support for automated manufacturing methods and any combination thereof.
Further benefit of the present fiber and fiber combination include less expensive raw material cost when compared to thermosets, lower processing temperatures than those current in use, improved thermoplastic composite processing options, and less expensive metal tools for processing, reduce or minimize structural failures, have high impact resistance, have a lighter weight than comparable fibers and fiber combinations, have vibration damping properties, dielectric properties, chemical resistance, and any combination.
The resulting fiber and fiber combination(s) of the present invention can provide for higher performance thermoplastic material, lower temperature processing, and improved physical and performance properties over existing technologies. In one embodiment, the reinforcement fiber can be combined with a low melt fiber wherein the low melt fiber can include a denier of less than about 1 grams/60 meters and the crystallinity according to WAXS measuring techniques can be greater than 50%. The reinforcement fiber can be taken from a group consisting of a polyolefin, a mixture of two or more polyolefins, a polyolefin having a nucleating agent. The low melt fiber can be a multifiber structure and can have a denier between about 10 Denier to 1000 Denier, but is not limited to this range. The reinforcement polyolefin can be polypropylene, polyethylene, polybutylene and can be a multifilament yarn. The reinforcement fiber can be any polymeric composition comprising propylene monomers, alone or mixture with other polyolefins, deniers, or other monomers including ethylene, butylene, and the like. The reinforcement fiber can have melt flow indices between about 0.2 and about 50 can be utilized in forming the disclosed multifilament yarns. The reinforcement fiber can be made with the process shown in U.S. Pat. No. 7,074,483 which is incorporated by reference.
In one embodiment, the present invention is created by combining two or more fibers into a resulting fiber. The combination can be accomplished by plying, twisting, air texturing, air entanglement, yarn made via the coating extrusion process, whereas the coated area has a lower melt than the core and the reinforcement fiber and the like. The first fiber can be a reinforcement fiber including a continuous filament yarn based on polypropylene resin. This fiber can be a UV-stabilized, opaque fiber with a general-purpose fiber sizing. The yarns are porous and generally cylindrical in form and are chemically stable. In one embodiment, the reinforcement fiber is made using a method that can include filament winding, weaving, knitting, braiding, and multiaxial construction. The reinforcement fiber, in embodiment, can be unwound for use. In one embodiment, the reinforcement fiber can include the following properties shown in Table 1:
In one embodiment, the second fiber can be a low melt fiber with a melting point that can be below 140° C. so that when heat is applied, the reinforcement fiber shrinkage is reduced or eliminated. The second fiber can include a high flow rate at low temperature including high flow rate at 110° C. or less. One or multiple low melt fiber(s) that can be used as the second fiber can include physical properties that are shown in TABLE 2.
The reinforcement fiber and the low melt fiber can be combined to form the resulting fiber by taking the reinforcement fiber and the low melt fiber, arranging them in an axial direction. The two or more fibers are then plied. In one embodiment, the reinforcement fiber and the low melt fiber are individually twisted, which can result in a ply twisted fiber. Prior to twisting or plying, loose fibers can be coalesced into a fiber strip. After twisting or plying, the outer fibers can be compressed towards the inner layers to create centripetal pressure, which can result in the strand gaining friction along the direction of the fiber elongation. Twisting or plying can create compact yarn structures, which have improved resistance to damage occurring from lateral external forces.
Once twisted, the outer fiber can be twisted back in an inclined spiral and the fibers twisted and deformed as the yarns are held together. The process can change the structural form and mechanical and physical properties of the fibers, as shown in
In one embodiment, there is a wrap angle that is defined by the yarn strip where the fibers exert centripetal pressure on the yarn strip. The greater the wrap angle, the greater the centripetal pressure applied. Therefore, the greater the angle of encirclement, the greater the centripetal pressure. The centripetal pressure compresses or squeezes the outer fibers towards the inner layer that can result in a tightness of the yarn strip and results in friction between the fibers. Therefore, the structural form, physical properties, and mechanical properties of the yarn strip are modified. In one embodiment, the plying or testing process includes two reinforcement fibers and three low melt fibers that are combined to a yarn. The twist can be applied at 1.0-2.5 twist per inch S or Z at 40.0-100 twists per meter, but is not limited to this range. The resulting fiber can include a denier of 3080, a tensile strength of 38 lbs, and a tenacity of 5.59 g/d. The tensile strength can be in a range of 30 to 40 lbs. The tenacity can be in a range of 4.50 to 6.50 g/d in one embodiment.
In one embodiment, another next step in the process includes joining the plied yarn into a fabric that can be used in an application. The fiber can be woven into fabric form, that can consist of 20%-80% or 80-20 percent respectively of reinforcement fiber and low melt fiber. During this process, the low melt fiber can melt under heat and pressure to become the matrix of the resulting fiber, whereas reinforcement fiber retains as a reinforcement. The weaving process can be illustrated by reference to
Once the fabric is provided, the fabric can be thermoformed using an exemplary process that includes the steps referred to in
In one embodiment, the following layup schedule is used as shown in Table 3.
The resulting fabric can exhibit physical properties that can include those shown in
In some embodiment, the reinforcement fiber can be combined with carbon, glass, aramid, and any combination in conjunction with a low melt fiber
The methods in which the reinforcement fiber can be added or combined with a second fiber for a resulting fabric can include adding a third fiber during the plying process that can create a single plied yarn which can be used for weaving. For example, carbon fiber and low melt polyester can be combined at the yarn level and woven. Further, a second reinforcement fiber can be added during the weaving process and can include using different wrap and fill fiber. Further, additional fibers and fabrics can be used in the layup schedule.
In one testing example, panels of a resulting fabric were created having difference layup order with the fiber orientation in each panel being orthogonal. Three tensile samples were taken from each panel. The tabs were cut from a glass fiber and epoxy composite and the area of the sample in which the tab is bonded was sanded lightly to introduce roughness and improve bonding to the low surface energy polymer samples. The tabs were rounded at the inner ends to limit stress concentrations and the samples were attached to the tabs. The samples were “double tabbed” to thicken the samples suitably for clamping in the tensile test machine.
In one tensile testing example, the test was performed using an MTS 647 Hydraulic Wedge Grips tensile machine with a test rate of 2 mm/min. An extensometer was used to measure strain over the first 0.005 mm/mm. Tensile modulus was calculated from 0.001 to 0.003 mm/mm strain. The results are shown in
In one testing example, panels were taken from the resulting fabric and flexure testing was performed using an MTS Three Points Bending machine (Instron model 1331) with a test rate of 1.9 mm/min. The span length of flexure testing is 70 mm. The results are shown in
In one testing example, un-notched samples and notched samples were prepared from the results fabric. Izod Impact testing was performed using a Tinius Olsen Izod impact test machine and in accordance with ASTM D256-10. The result is shown in
In one tensile testing method an Instron Model 1331 frame tensile machine was used having a test rate of 2 mm per minute. An extensometer was used to measure strain over the first 0.005 mm/mm. Tensile modulus was calculated from 0.001 to 0.003 mm/mm strain. The sample testing results as shown in
As shown, the tensile strength of the sample was found to be in the range of 210 to 239 MPa with an average of 230.08 MPa according to some tests. As shown the module of the sample was found to be in the range of 5.10 GPa to 6.4 GPa with an average of 5.55 according to some tests. Further testing results using the frame tensile machine as shown in
A flexure test was performed using an MTS Three Points Bending machine, such as the Instron model 1331 with a test rate of 1 mm per minute. The span length of flexure testing was 28 mm. Using this flexure testing, the results as shown in
Referring to
The invention can be configured so that it does not undergo chemical property changes when heated or cooled, even when heated and cooled multiple times, thereby allowing for improved recycling properties. Reference will now be made in detail to various embodiments of the invention, one or more examples of which are set forth below. Each embodiment is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used in another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.
This application is a United States Patent Application claiming priority in U.S. Provisional Patent Application Ser. No.: 63/385,026 filed Nov. 27, 2022 and incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63385026 | Nov 2022 | US |
