Improved long fiber reinforced polymer composite flakes having gradual edges, method of providing same, and articles formed therefrom having improved strength and impact resistance - Patents.com

Abstract

Methods of providing improved polymer composite flakes for use in forming articles, articles formed therefrom, and improved polymer composite flakes are described, and resulting articles formed from such improved polymer composite flakes have enhanced tensile strength and impact resistance, particularly at high speeds, and a method of increasing the average tensile strength and / or impact resistance of articles formed from polymer composites by using the improved polymer composite flakes is described herein. The method includes providing a composite having at least one polymer matrix material and long reinforcing fibers of a first fiber material extending through the polymer matrix material, and forming at least one flake from the composite, the at least one flake having an outer surface with an outer edge, a portion of the outer edge configured to provide at least one outer edge feature on the outer edge of the at least one flake, thereby providing the improved polymer composite flake.

Description

[Technical field]

[0001] This nonprovisional patent application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 63 / 315,022, filed on February 28, 2022, and entitled “Modified Long Fiber Reinforced Polymeric Composite Flakes Having Progressive Ends, Methods of Providing the Same, and Articles Formed Therefrom Having Enhanced Strength and Impact Resistance,” the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] The present invention relates to the field of forming discontinuous long fiber polymer composite articles from discontinuous long reinforcing fiber feedstock in the form of flakes which may be formed from continuous long fiber composite prepregs such as tapes, and more particularly to the manufacture of such articles in which the tensile strength, impact resistance, especially at high speeds, and fatigue limit of the resulting article are increased by providing improved discontinuous long reinforcing fiber polymer matrix composite flakes having improved edge characteristics forming gradual edges.

[0003] Articles formed from discontinuous long fiber composites are known in the art and are generally formed from various types of thermoforming processes. Articles may be formed from continuous long fiber composites, such as rod stock, pellets, composite blocks, and composite tapes, which may be pre-fabricated composites that may be chopped and reshaped to create feedstock shapes such as plates, flakes, or various particles for use in forming final products. Such feedstocks may be chopped to have short or long fibers within the feedstock. Reinforcement flakes, one known composite feedstock material, are formed by cutting, chopping, or using waste portions of unidirectional tapes or similar long fiber reinforced continuous composites. Such composite tapes may incorporate reasonably high fiber loadings, and thus flakes formed from such tapes may provide feedstocks with high fiber loadings. The flakes may be chopped to provide discontinuous long fiber reinforced flakes. Once molded, articles formed from such flakes can contain a random distribution of discontinuous long fibers, and may also contain some short fibers and / or long continuous fibers, if desired.

[0004] Various molding methods are known and can be modified to obtain different results from such feedstocks, including the use of modified properties and / or altered levels of random fiber orientation within the matrix polymer.

[0005] The advantages of using unidirectional tapes as described above to form flakes as feedstock for use in forming final products are the high fiber loadings that can be obtained, good "wet-out" of the fibers by the matrix polymer, as well as good fiber distribution, low waste processing, and the ability to create complex molded shapes that can approach those formed from injection molding. However, the disadvantage of discontinuous long fiber flake materials formed from such unidirectional tapes is that such flakes generally tend to result in articles with lower tensile strength than desired, although they have good properties and generally random distribution. For example, typical values ​​for discontinuous long fiber articles using carbon fibers as reinforcing fibers in a polyarylene matrix, such as a polyetheretherketone matrix, are about 200 to about 220 MPa. There is a need in the art to attempt to improve the strength of composites formed from chopped feedstock, especially those formed from discontinuous long fiber composite flakes.

[0006] European Patent Application No. 3421207 provides one prior art method for forming composite articles of discontinuous fiber reinforced material. In this patent, the discontinuous reinforcing bundles incorporate cut surfaces inclined at a predetermined angle to the orientation direction of a single yarn, resulting in different lengths of fiber bundles. The longer the bundle, the smaller the tip angle of the ends of the discontinuous fiber bundles. Such composites are used to form molded products of discontinuous fiber reinforced composites requiring high flowability, two-dimensional isotropy, and small variations in mechanical properties.

[0007] No. 6,251,809 describes a discontinuous fiber composite in which the fibers are treated to adhere to a polymer matrix in the warp and weft of a fabric pattern, the warp being cut into a series of patterns.

[0008] No. 8,709,319 describes the molding of flakes into thermoplastic articles having fibers of different lengths. The flakes may be formed from rolls of unidirectional tape cut into various shapes and using various fiber lengths.

[0009] No. 9,283,706 describes forming flakes for molding, which may be formed of thermoplastic resin and discontinuous fibers. The flakes may be generally rectangular or other shapes, including oval, to provide fibers of different lengths for more isotropic properties and strength.

[0010] No. 10,160,146 teaches a molding method using a feedstock of chopped or chopped long fiber prepreg material, which may contain discontinuous long fibers and is in the form of a fiber reinforced cloth, tape, or rod. This material is fed into a first molding section in a single mold, the first molding material having discontinuous long reinforcing fibers. This material is extruded through a port and molded in the molding section of the mold, providing a stronger, more uniform molded part due to improved fiber orientation.

[0011] U.S. Patent No. 8,529,809 provides a description of forming composite plates with layers arranged in various directions, creating a composite described in the patent as a quasi-isotropic panel. A cutting tool cuts and separates the composite to form quasi-isotropic flakes from the panel. Tools such as lasers, saws, punches, or other structures can be used to create squares, ellipses, circles, rectangles, and triangles.

[0012] U.S. Pat. No. 5,151,322 describes a composite plate formed from randomly arranged strips of unidirectionally oriented reinforcing fibers cut from a tape to provide quasi-isotropic strength.

[0013] U.S. Patent No. 9,302,434 includes a movable cylindrical mold for providing flakes, which are described as being formed from thermoplastics having fibers of carbon, glass or other materials that can be made by chopping unidirectional thermoplastic prepregs into the desired size and shape. Although the flakes are shown as rectangular, the patent states that other shapes are possible.

[0014] US Patent Publication No. 2013 / 0189478 discloses using narrow flakes with a height to width ratio of at least 6:1 to form composites with consistent and uniform strength.

[0015] No. 9,724,854 describes forming a composite from chips formed from unidirectional tape using a thermosetting resin. The chips are rectangular in structure, but may be other shapes depending on how the unidirectional tape is chopped.

[0016] Thus, while flakes or chips of various sizes and shapes have been used to form various articles in attempts to improve the strength of the resulting articles and / or provide more uniform properties in the articles, there remains a need in the art to significantly improve the overall strength and uniformity of properties throughout articles formed from polymeric composite flakes, improve the impact resistance, particularly at high velocities, and improve the fracture limits of articles formed from polymeric composite flakes. Moreover, it would be desirable to achieve such goals using an economical, low-waste process that uses composite flakes as a molding feedstock, while providing easy-to-use equipment for molding the flakes. Summary of the Invention

[0017] The present invention includes methods of forming improved polymer composite flakes for use in forming articles, articles formed from the resulting improved polymer composite flakes, the improved polymer composite flakes for use in forming articles, and an apparatus for forming the improved polymer composite flakes.

[0018] In one embodiment herein, the invention comprises a method of providing an improved polymer composite flake for use in forming an article, the method comprising: (a) providing a composite having at least one polymer matrix material and long reinforcing fibers of a first fiber material extending through the polymer matrix material; and (b) forming at least one flake from the composite, the at least one flake having an outer surface having an outer edge, a portion of the outer edge configured to provide at least one outer edge feature on the outer edge of the at least one flake, thereby providing an improved polymer composite flake.

[0019] The method may further include forming at least one flake by cutting the composite to form at least one flake. The at least one flake may be cut by a cutting device. The composite may be in a form selected from a tape, a plate, and a sheet. The long reinforcing fibers in the composite may extend in one direction. The long reinforcing fibers in the composite may be continuous long reinforcing fibers. In another embodiment, the composite is in the form of a tape and the long reinforcing fibers may be continuous long reinforcing fibers extending in one direction. The long reinforcing fibers in the composite may be continuous long reinforcing fibers.

[0020] In further embodiments of the method, at least one peripheral feature may have at least two angled sides. Such at least two angled sides of the peripheral feature may be angled toward one another at an angle of about 5° to about 120°, about 20° to about 90°, about 20° to about 60°, or about 30° to about 60°. In such method embodiments, the at least two angled sides of the peripheral feature may be contiguous and together form an angle apex at a contact point between the at least two angled sides.

[0021] In the method, there may be, in one or another embodiment, a plurality of peripheral features. In such an embodiment having a plurality of peripheral features, at least two of the plurality of peripheral features may also be contiguous such that at least two angled sides of each peripheral feature are contiguous and together form an apex of an angle at a contact point between the at least two angled sides, and the portion of the peripheral feature having at least one peripheral feature has a zigzag pattern. In a further embodiment of the method, the peripheral edge of at least one modified polymer composite flake may have at least three peripheral edges, and at least two of the peripheral edges have a zigzag pattern.

[0022] In such an embodiment, the long reinforcing fibers in the at least one improved polymer composite flake may extend unidirectionally, extending in a first direction through the at least one polymer composite flake, and the outer edge having the zigzag pattern may extend in a second direction angled relative to the first direction. The angle between the second direction and the first direction may be about 90°, or may be from about 60° to about 90°.

[0023] At least one peripheral feature in the above-described method embodiment may be configured to have a shape selected from a triangular shape (such as the zigzag pattern described above), but also a parabolic shape, a parallelogram shape, a bell shape, a bullet shape, an arrowhead shape, and / or a trapezoid shape. When there are two or more peripheral features, each peripheral feature may be the same or different. Furthermore, when there are two or more peripheral features, the peripheral features may together form a pattern. Also, at least one peripheral feature may be in the shape of a parallelogram, such as a rectangle, in another preferred embodiment, for example to form a rectangular toothed configuration in the pattern configuration.

[0024] In this method, at least one modified polymer composite flake may have four outer edges, two of which are opposing outer edges, each of the opposing outer edges having a pattern formed thereon such that the pattern extends along substantially all of the two opposing outer edges, and such that the distance between the two opposing outer edges measured longitudinally across the at least one modified polymer composite flake remains substantially the same throughout the pattern.

[0025] In the above method, the polymer matrix material may be a thermoplastic, and may be one or more of polysulfone, polysulfide, polyimide, polyaramid, polyamideimide, polyamide, polyarylene polymer, fluoropolymer, and combinations and copolymers thereof. The polymer matrix material may be a polyarylene polymer, which may be one or more of polyetherketone, polyetheretherketone, polyetherketoneketone, and combinations and copolymers thereof. The polymer matrix material may be a fluoropolymer, which may be at least one of a copolymer of tetrafluoroethylene and at least one perfluoroalkylvinyl ether, a copolymer of tetrafluoroethylene and at least one other perfluoroalkylene, polychlorotrifluoroethylene, ethylchlorotrifluoroethylene, ethyltrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, and combinations and copolymers thereof.

[0026] The long reinforcing fibers in the at least one modified polymer composite flake used in the method may be one or more of inorganic fibers, ceramic fibers, glass fibers, graphite fibers, carbon fibers, and organic fibers, which may be thermoplastic or thermoset fibers, and combinations thereof.

[0027] In one embodiment, the perimeter of at least one of the improved polymer composite flakes of the above-mentioned method may define a surface region on the outer surface of at least one of the flakes having an overall shape that is generally a triangle, a polygon having at least five sides, a circle, a parallelogram, or a trapezoid, and the perimeter feature may be formed on at least one edge of such surface region shape. The surface region defined by the perimeter may be a parallelogram selected from a square, a rectangle, and a diamond.

[0028] In another embodiment, there is a plurality of flakes, each having a surface area defined on the flake's exterior by an outer edge of the flake and a thickness measured along the outer edge of each flake in a plane perpendicular to the surface area of ​​the flake, and the average outer surface area of ​​the plurality of flakes may be from about 20 square millimeters to about 650 square millimeters, and the average thickness of the plurality of flakes may be from about 0.05 mm to about 0.25 mm. In yet another embodiment of the method, the average outer surface area of ​​the plurality of improved polymer composite flakes is from about 20 square millimeters to about 325 square millimeters. In a further embodiment, the average outer surface area of ​​the plurality of flakes is from about 150 square millimeters to about 170 square millimeters, and the average thickness of the plurality of flakes is from about 0.1 mm to about 0.20 mm.

[0029] When an article is formed using a plurality of modified polymer composite flakes having peripheral features in the manner described above, the formed article can have an average tensile strength that is at least about 30% greater, or at least about 40% to about 60% greater, than the tensile strength of an article formed using a plurality of flakes formed from the same material and having the same overall shape and size, but lacking peripheral features.

[0030] At least one peripheral feature in this method may have at least two angled sides, and the at least two angled sides of each peripheral feature on the at least one modified polymer composite flake may be contiguous and together form an angle apex at a contact point between the at least two angled sides, and there may be a plurality of peripheral features on the at least one modified polymer composite flake, and at least two of the angled features of the plurality of peripheral features may also be contiguous such that a portion of the peripheral edge of the at least one modified polymer composite flake has a zigzag pattern.

[0031] The zigzag pattern on the at least one modified polymer composite flake may have from about 2 to about 12 peripheral features, preferably from about 4 to about 8. Additionally, the at least one modified polymer composite flake may include at least three peripheral features, at least two of which have a zigzag pattern. In such embodiments, the zigzag pattern may have from about 4 to about 8 of said peripheral features.

[0032] The invention also includes, in another embodiment, an article formed by heat forming or curing a plurality of the modified polymer composite flakes formed by the method as described above, depending on the matrix polymer. Such an article may be a component, device, or part for use in high temperature and / or pressure end uses, or in aircraft, medical devices, robotics, automotive, semiconductor, or sports end uses. The article may also be a bracket, cover, fairing, or cabin sidewall attachment for use in an aircraft. The article may also be a containment shell.

[0033] The article may be formed by heat molding or curing a plurality of modified polymer composite flakes together with unmodified polymer composite flakes that may be the same or different from at least one modified polymer composite flake formed by the methods described herein. The unmodified polymer composite flakes in such instances may incorporate the same polymer matrix material and the same long reinforcing fibers as at least one modified polymer composite flake formed by the methods described herein.

[0034] The invention further includes, in another embodiment, a method of increasing one or more of average tensile strength, high velocity impact resistance, and fatigue resistance of an article formed from composite flakes having at least one polymer matrix material and long reinforcing fibers extending through the polymer matrix material, the composite flakes having an outer surface with at least one outer edge. The method may include providing a plurality of modified polymer composite flakes, each of the modified polymer composite flakes having an outer edge feature along a portion of the outer edge of the flake, and forming an article using a plurality of said modified polymer composite flakes.

[0035] Further embodiments of the invention herein include an improved polymer composite flake for making an article, the improved polymer composite flake having an outer surface having an outer edge, the outer edge defining an outer surface area on the outer surface, the improved polymer composite flake having a thickness along the edge extending in a direction generally perpendicular to the outer surface area defined by the edge, a polymer matrix material, long reinforcing fibers within the polymer matrix material, and at least one outer edge feature on a portion of the outer edge of the flake.

[0036] The shape of the peripheral features of such modified polymer composite flakes may be selected from triangular, parabolic, parallelogram, bell, bullet, arrowhead, and trapezoidal shapes. Also, the modified polymer composite flakes may have two or more peripheral features, and each peripheral feature may be the same. There may be two or more peripheral features that together form a pattern.

[0037] The long reinforcing fibers in the improved polymer composite flakes herein may extend unidirectionally within the polymer matrix material. The improved polymer composite flakes may be formed from composites having long reinforcing fibers that extend unidirectionally and are continuous.

[0038] The outer edge feature may have at least two angled sides that are angled towards one another at an angle of about 5° to about 120°, about 20° to about 90°, about 20° to about 60°, or about 30° to about 60°. In such embodiments, the two angled sides of the outer edge may be contiguous and together form an angle apex at the point of contact between the at least two angled sides.

[0039] In another embodiment, there may be a plurality of peripheral features, each having at least two angled sides. At least two peripheral features of the plurality of peripheral features may also be contiguous, together forming an angle apex at a contact point between the at least two angled sides. At least two peripheral features of the plurality of peripheral features may also be contiguous such that at least a portion of the peripheral edge of each of the flakes having peripheral features has a zigzag pattern. Each of the improved polymer composite flakes may have at least three peripheral edges, at least two of which have a zigzag pattern.

[0040] The long reinforcing fibers of each of the modified polymer composite flakes are unidirectional fibers that extend in a first direction through the modified flake, and at least a portion of the outer edge of each of the flakes having a zigzag pattern extends in a second direction, where the second direction is at an angle to the first direction, where the second direction may be perpendicular to the first direction or the second direction may be at an angle of about 60° to about 90° to the first direction.

[0041] In another embodiment of the improved polymer composite flakes herein, the polymer matrix material may be a thermoplastic resin and may be one or more of polysulfone, polysulfide, polyimide, polyamideimide, polyamide, polyarylene polymer, fluoropolymer, and combinations and copolymers thereof. The polymer matrix material may also be a polyarylene polymer, which is one or more of polyetherketone, polyetheretherketone, polyetherketoneketone, and combinations and copolymers thereof. The long reinforcing fibers in the composite may be one or more of inorganic fibers, ceramic fibers, glass fibers, graphite fibers, carbon fibers, organic fibers including thermoplastic and thermoset fibers, and combinations thereof.

[0042] In another embodiment of the improved polymer composite flake herein, there may be a plurality of peripheral features on the improved flake, each of the peripheral features may have at least two angled sides, the at least two angled sides may be contiguous and together form an apex of the angle at a contact point between the at least two angled sides, and further, at least two peripheral features of the plurality of peripheral features may also be contiguous such that at least one edge of the peripheral features with the peripheral features on each of the improved polymer composite flakes has a zigzag pattern. There may be about 2 to about 12 peripheral features in the zigzag pattern, and preferably there may be about 4 to about 8 peripheral features in the zigzag pattern. The improved polymer composite flake may have at least three peripheral features, at least two of which have a zigzag pattern. In such an embodiment, there may be about 4 to about 8 peripheral features in the zigzag pattern.

[0043] In yet another embodiment of the present invention, an apparatus for forming improved polymer composite flakes for use in forming articles is provided, the apparatus comprising: a feeder for controllably feeding a portion of the composite, the portion of the composite configured and sized to form a flake, the composite including at least one polymer matrix material and long reinforcing fibers extending through the polymer matrix material in the polymer composite; and a movable, controllable cutting device comprising one or more removable cutting templates configured to operate as a guillotine to cut the portion of the composite fed by the feeder into flakes and provide at least one peripheral feature on a portion of an edge of the flake cut from the cutting device. In one embodiment, the apparatus may further comprise a controller for controllably operating the feeder and / or the cutting device. Different cutting templates may be used to provide different edge features on different edges of the cut flakes.

[0044] The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments that are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and equipment shown. In the drawings, [Brief description of the drawings]

[0045] [Figure 1] FIG. 2 is a top view of a representative depiction of a prior art type composite flake that may be used in embodiments of the methods herein and used to manufacture the comparative samples in Examples 1, 2, and 3 herein. [Figure 1A] FIG. 2 is a side elevational view of the composite flake of FIG. 1. [Diagram 2] FIG. 2 is a representative perspective view of an alternative flake that may be used in one embodiment of the method herein. [Diagram 3]FIG. 2 is a representative top view of an improved flake having peripheral features according to embodiments herein and produced according to embodiments of the method herein and used to produce inventive Samples A, B, and C in Example 1 herein. [Figure 3A] FIG. 2 is a top view of one embodiment of the improved flake sample 30-4 used in Example 2 herein. [Figure 3B] FIG. 2 is a top view of one embodiment of the improved flake used in Sample 60-4 of Example 2 herein. [Figure 3C] FIG. 2 is a top view of one embodiment of the improved flake used in Sample 90-4 of Example 2 herein. [Figure 4] FIG. 4 is a representative perspective view of the improved flake of FIG. [Figure 5A] FIG. 1 is a plan view of one embodiment of the improved flake used in Example 2, Sample 30-8. [Figure 5B] FIG. 1 is a plan view of one embodiment of the improved flake used in Example 2, Sample 60-8. [Figure 5C] FIG. 1 is a plan view of one embodiment of the improved flake used in Example 2, Sample 90-8. [Figure 6A] FIG. 1 is a plan view of one embodiment of the improved flake used in Example 2, Sample 30-12. [Figure 6B] FIG. 1 is a plan view of one embodiment of the improved flake used in Example 2, Sample 60-12. [Figure 6C] FIG. 1 is a plan view of one embodiment of the improved flake used in Example 2, Sample 90-12. [Figure 6D] FIG. 1 is a plan view of one embodiment of the improved flake used in Example 2, Samples 5-12. [Figure 6E] FIG. 1 is a plan view of an embodiment of the improved flake used in Example 2, Sample 15-12. [Figure 7A] FIG. 1 is a plan view of one embodiment of the modified flake used in Example 2, Sample 6×2. [Figure 7B]FIG. 1 is a plan view of an embodiment of the improved flake used in Example 2, Sample 6×1. [Figure 8A] FIG. 13 is a plan view of an embodiment of the improved flake used in Example 2 as Comparative Sample D. [Figure 8B] FIG. 13 is a plan view of an embodiment of the improved flake used in Example 2 as Comparative Sample E. [Figure 9] 1 is a graphical representation of the average tensile strength (MPa) of articles formed from the improved flakes for the inventive and comparative samples of Example 2. [Figure 10] 1 is a graph showing the average tensile strength (MPa) of articles formed from the modified flakes of the inventive sample and the comparative sample of Example 2 as a function of the depth (mm) of any peripheral features present, where the depth represents the length cut into the original composite flake for the peripheral feature. [Figure 11] 1 is a graph showing the tensile strength in MPa of articles formed from unmodified commercial polymer flake and modified versions of the same commercial flake as in Example 1. [Figure 12] 13 is a photographic image of a fixture for mounting test samples of composite plates in high velocity impact testing of Example 3. [Figure 13] FIG. 5 is a graphical representation of the impact velocity of aragonite on the composite plate tested in Example 3 for various samples tested having modified flake designs as in FIGS. 3 and 4, and a comparative sample formed in the manner of Comparative Sample D in Example 2. [Figure 14] FIG. 1 is a plan view of an improved flake configuration according to an embodiment of the invention having a pattern of triangular edge features on the edge of the flake, where successive edge features are joined by a single contact point and the edge features have angled sides that connect at a vertex. [Figure 15] FIG. 1 is a plan view of an improved flake configuration according to an embodiment of the invention having a pattern of parabolic edge features on the edge of the flake, where successive edge features are joined by a single contact point, and the edge features have curved sides and connect at a terminal curve. [Figure 16] FIG. 1 is a plan view of an improved flake configuration according to an embodiment of the invention having a pattern of parallelogram-shaped peripheral features on the edge of the flake, where the peripheral features are connected by substantially straight edges and the sides are angled sides that are parallel to one another but connected at their ends by straight edges that join. [Figure 17] FIG. 1 is a plan view of an improved flake configuration according to an embodiment of the invention having a curved pattern on the edge of the flake, where successive peripheral features are connected by curved edges and the edge features have parallel but partially straight sides that curve towards each other at the ends of the edge features to form a semicircular end that gives the peripheral feature the appearance of the end of a tongue depressor, or a bell shape where the sides of the bell are partially straight and parallel. [Figure 18] FIG. 1 is a plan view of an improved flake configuration according to an embodiment of the invention, in which an edge feature is provided on the edge of the flake, the edge feature being in the form of a triangle extending outwardly from one edge of the flake and two half triangles extending outwardly from the opposite edge of the flake (to define an inwardly extending triangle) having a point and extending along the length of the edge such that the fiber length remains substantially constant along the flake. [Figure 19] FIG. 1 is a plan view of an improved flake configuration according to one embodiment of the present invention, in which the flake has a pattern on opposing edges of the flake formed from two different types of peripheral features, one rectangular peripheral feature (having parallel sides and terminating in a straight edge) and one bullet-shaped peripheral feature (having curved sides that connect at a sharply curved end); these features are shown in an alternating pattern extending along a first peripheral edge of the flake and extending in an inverse pattern on the other opposing peripheral edge of the flake such that fiber length remains substantially constant along the flake; and the alternating peripheral features on each side are connected by a substantially straight edge. [Figure 20]FIG. 1 is a plan view of an improved flake configuration according to an embodiment of the invention, in which edge features are provided on the edges of the flake in the form of a single fully curved feature that extends convexly outward on one edge of the flake and along the length of the edge, and a concave curved feature that extends outward (to define an inwardly extending curved feature) on the opposing edge of the flake, with the fiber length remaining substantially constant along the flake. [Figure 21] 1 is a plan view of an improved flake configuration according to an embodiment of the invention, the flake having a pattern formed on opposing edges of the flake, the peripheral feature being an "arrowhead" shaped peripheral feature, the arrowhead shape being formed from a base rectangular portion and a terminal triangular portion, the sides of the terminal triangular portion joining at vertices, and the rectangular portions of each peripheral feature being connected by substantially straight edges, the pattern extending across a first peripheral edge and an inverse pattern extending across the opposing peripheral edge of the flake. [Figure 22] FIG. 1 is a plan view of an improved flake configuration according to an embodiment of the present invention, the flake having a pattern formed of rectangular peripheral features having parallel straight sides connected at their ends by straight terminal portions, the peripheral features being connected by substantially straight edges. [Figure 23] FIG. 1 is a plan view of an improved flake configuration according to an embodiment of the present invention, the flake having a pattern on opposing edges of the flake, the outer edge features being formed in a "dovetail" shape and appearing as isosceles trapezoids having angled sides and ends joining angled sizes that are straight ends, the outer features being connected by substantially straight edges. [Figure 24] FIG. 2 is a photographic representation of an apparatus for forming improved flakes according to the methods herein. [Figure 24A] FIG. 25 is a photograph of two removable cutting templates for use with the apparatus of FIG. 24. [Diagram 25]FIG. 1 is a graphical representation of peak stress (MPa) versus cycle number from fatigue testing data for Example 4 specimens formed from Comparative Sample X (a composite formed from unmodified flakes formed according to Example 1) and Inventive Sample Y (a composite formed from modified flakes formed according to Example 1). [Figure 26] FIG. 1 is a graphical representation of the type of damage caused by high velocity hailstone impacts on composite plates tested in Example 5 formed from Comparative Sample X composite, Inventive Sample Y composite of Example 4, and Composite Inventive Sample Z formed from a rectangular modified flake design providing longer fibers in the length direction and the same edge modification as Inventive Sample Y on the widthwise edges of the modified flake. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] As used herein, the terms "inner" and "outer", "upper" and "lower", "inner" and "outer", "external" and "internal", "right" and "left", "upper" and "lower", "distal" and "proximal", and words of similar importance, unless otherwise specified, refer to directions in the drawings to help clarify the features of the invention.

[0047] The present invention also includes a method of providing the improved polymer composite flake for use in forming articles, the improved polymer composite flake and articles formed therefrom having enhanced tensile strength, increased impact strength, particularly in high velocity impact situations, and increased fracture limits, as well as an apparatus for making the improved polymer composite flake.

[0048] The improved polymer composite flakes herein may be formed from various flakes that are variously cut, stamped, molded, or otherwise formed from the composite. In embodiments herein, the composite is formed from a polymer matrix material that includes at least one long fiber formed from a first fiber material. Such flakes may be purchased commercially or may be independently formed and then provided for use in the methods herein.

[0049] When forming flakes from composites, the composites are preferably preformed composites with long reinforcing fibers extending within the composite, taken from either individual fibers, tows, braids or bundles. The composites may also be formed from woven reinforcing fibers incorporated into a polymer matrix material, or may use long reinforcing fibers extending in one direction that can extend through the polymer matrix material. In a preferred embodiment, the fibers extend in one direction and are preferably long reinforcing fibers. The long reinforcing fibers may be continuous or discontinuous. Similarly, these same types of reinforcing fibers useful for producing composites that can be used in the methods herein to provide flakes are also preferably the same as those in the flakes provided by the methods herein. Furthermore, the same polymer matrix material used to form the composites is preferably the same polymer matrix material as those in the flakes provided by the methods herein.

[0050] The long reinforcing fibers in the reinforcement material in the improved polymer composites herein and the same first fiber material may be a single type of fiber material or a blended material, i.e., two or more types of fiber materials may be used in combination as the reinforcing long fiber material for impregnation, addition, or other application of a polymer matrix material to substantially wet such long reinforcing fibers to form a composite, and finally, from such composite to form the improved polymer composite flakes provided herein.

[0051] Examples of suitable long reinforcing fiber materials ("first fiber materials") include various long reinforcing fibers, for example, but not limited to, ceramic fibers, glass fibers, graphite fibers, carbon fibers, quartz fibers, alumina fibers, silicon carbide fibers, basalt fibers, boron fibers, and inorganic fibers such as glass / carbon, glass / graphite / carbon, graphite / carbon, ceramic / glass, and combinations thereof. Additional organic fibers, such as thermoplastic and thermoset long reinforcing fibers, can also be used, with first fiber materials such as aramid fibers, polybenzoxazole fibers, which can be used alone or blended with glass fibers, ceramic fibers, and carbon fibers.

[0052] In fiber blends or composite fiber reinforcements, additional fibers may be provided to the fiber matrix prior to impregnation in the form of chopped strands, filaments, or whiskers. Additionally, such blends may include bundles, tows, and braids that run in the direction of the long fibers, and / or various woven or blended fibrous materials that run in two or more directions to impart strength and / or other desired properties.

[0053] Preferred long fiber materials include ceramic, glass, graphite, carbon, and / or plastic (thermoplastic and thermoset) fibers, such as aramid fibers (available as Kevlar®, Twaron®, and Technora®) or polybenzoxazole fibers available as Zylon®.

[0054] The long reinforcing fibers may be continuous or discontinuous fibers extending in one or both directions (preferably bidirectional fibers with about 50% of the fibers in the parallel direction and about 50% of the fibers in the perpendicular direction), stretched broken fibers, braided fibers, and woven continuous fibers. Preferably, the reinforcing fibers extend in one direction. Additionally, the reinforcing fibers may be braided or intertwined. Preferred diameters of the long reinforcing fibers typically include about 0.1 microns, about 5 to about 15 microns, and about 7 to about 10 microns, depending on the fiber selected. Boron fibers may range from about 100 microns to about 140 microns, and glass fibers may range from about 5 microns to about 25 microns. Basalt fibers may range from about 10 microns to about 20 microns.

[0055] It is preferred that the long reinforcing fibers comprise at least about 30 volume percent, preferably at least 40 volume percent, more preferably at least 50 volume percent, for example about 60 volume percent to about 90 volume percent, of the composite used to form the improved polymer composite flakes provided herein with respect to the total volume of the composite. It is preferred that the long fibers comprise at least about 40 volume percent to about 80 volume percent of the composite, and most preferably at least about 50 volume percent to about 70 volume percent of the composite, although it is understood that the preferred volume may be higher or lower with different fibers having different diameters.

[0056] The long reinforcing fibers used in the composites used to provide the improved polymer composite flakes herein can be incorporated into composites such as prepregs or other impregnated composite structures containing long fibers by any suitable technique known in the art or hereafter developed, provided that the resulting structure is suitable for use in forming polymer composites for use in forming the articles herein. It is also within the scope of the invention herein that the improved polymer flake materials herein can be formed by direct molding, such as by placing a composite containing long reinforcing fibers into a mold or stamping it into the improved flake shape.

[0057] In a preferred embodiment herein, continuous long reinforcing fiber structures such as impregnated continuous fiber tapes, plates, sheets, fabrics, and the like can be used. As used herein, the continuous fibers in such structures generally have a length of at least about 0.20 inches, and in embodiments herein, at least about 0.5 inches (1.27 cm). A length of at least 0.5 inches allows for a combination of easy processing and good resulting properties. It is known that longer fibers typically result in better mechanical properties, but are not necessarily easier to process. Thus, one skilled in the art will appreciate that fiber lengths can be selected to balance the mechanical properties and processing conditions for a given process. Such structures or other continuous fabric tapes, plates, sheets, rod stock, and the like can be cut, chopped, stamped, or otherwise formed into composite flakes of various sizes, but preferably maintain some or most of the original long reinforcing fiber length, such that the flakes are preferably discontinuous long fiber flakes. Examples of such structures that are preferred for forming improved polymer composite flakes for use in the methods herein are those having long reinforcing fibers with a length to diameter ratio of greater than about 100.

[0058] Such continuous long reinforcing fiber composite structures are then cut by a cutting device, chopped, stamped, die cut, or otherwise formed into improved polymer composite flakes herein. In one preferred embodiment herein, an apparatus A, shown in FIG. 24 herein, is provided for forming flakes for use in forming articles. In apparatus A, a feeder D controllably feeds a portion of a polymer composite, shown as a polymer composite unidirectional tape E, toward a cutting device G. The portion of the composite fed may be configured and sized to form a flake and thus set for a given size of flake. If half inch flakes are used and then improved according to the present invention, the feeder D may feed half inch portions to the cutting device G. The composite may have a polymer matrix material and long reinforcing fibers extending through the polymer matrix in the composite according to any of the embodiments described elsewhere herein. The feeder D may be controlled by a motor-driven feed controller J set for a particular size of flake.

[0059] The cutting device G is movable across the composite tape, preferably in a reciprocating motion. Depending on the cutter design or orientation, it may be an up-down stroke cut or a left-right stroke cut. As shown, a guillotine type blade GB is centrally located within the cutting device G to cut the composite tape E as it passes through the cutting area in the center of the cutting device. The controllable cutting device may be set to operate at a constant interval speed to cut edge features into a portion of the composite tape as it passes through the device. For example, as shown, the guillotine type blade (GB) opens to allow the template plate (described below) to move apart while the motor "J" drives the rollers to move the composite tape forward a length corresponding to the desired or set flake length. At the moment the tape stops moving, the guillotine type blade GB pushes downward to cut the tape and the process is repeated. Thus, G acts as a camshaft synchronized to the movement of the motor J. Thus, G includes a cutting blade (GB) also synchronized to the movement of the motor J. Once the composite tape has been cut, for example with a zigzag cut, the guillotine blade (GB) lifts and reopens for the next portion of tape advanced by operation of motor J. In this manner, flakes can be formed from the composite tape by motor J moving the tape forward in a synchronous manner, and the selected cutting pattern can be repeated for each desired flake length and cut.

[0060] The cutting apparatus G includes one or more removable cutting templates Q, shown in FIG. 24A, which are configured to be removably mounted within the cutting apparatus using any suitable fasteners or pins. As shown, fastener openings X are provided in the template Q for securing the template within the apparatus. The templates may be fabricated with various cutting teeth T to provide at least one peripheral feature to one or more portions of the edge of the improved flakes formed during cutting of the composite tape using the cutting apparatus G.

[0061] As shown, the cutting template Q may be provided with teeth T, such as by machining or other tooling, to provide the desired edge features as shown. In the exemplary template Q shown in FIG. 24A, the template may provide triangular perimeter features on opposing edges of the flakes while simultaneously cutting from the unidirectional tape such that the improved polymer composite flakes may be cut in the same cutting device G and simultaneously provided with features. However, it should be understood by those skilled in the art based on the present disclosure that various templates Q may be made to cut different perimeter features on the flakes in the cutting device and that the templates may be interchanged for different cuts in a modular manner. Additionally, it should be understood that any cutting method for forming reinforced long fiber flakes from a composite having long fibers, which may be continuous long fibers, is within the scope of the present invention, including the cutting process described above, die cutting, hand forming, or direct forming, such as by thermoforming of pre-sized flakes.

[0062] The apparatus may further include an integrated or independently operable controller for controllably setting and operating the feeding and / or cutting devices. A control such as the numerical control of the cutting device G described above may be used to control the operation of the motor J that advances the composite tape and may also be used to control the motor that drives the camshaft of the cutting device G, thus controlling the position of the guillotine blade (GB). Although the apparatus A is shown for use in forming the improved polymer composite flakes of the examples herein, it may be formed on a larger industrial scale with a variety of feeding and cutting devices having interchangeable or fixed cutting templates.

[0063] The improved polymer composite flakes herein may be of various sizes and shapes, as further discussed herein. In addition, the composites used to produce the commercially available flakes may also be used in the process to provide the improved polymer composite flakes herein. In the composites used as feedstocks, the long fibers may remain continuous long fibers in the resulting improved polymer composite flakes, or the improved polymer composite flakes used may be formed or cut therefrom to include discontinuous long fibers. The commercially available flakes may also be combined with the improved polymer composite flakes formed as herein to create articles, such different types of flakes being mixed together before molding or otherwise thermoforming the article.

[0064] 1 and 1A, when used in conjunction with the modified polymer composite flakes according to the present method, the standard polymer composite flakes referred to herein, i.e., unmodified composite flakes, may be generally represented with reference to an example polymer composite flake 10, having a length l extending inwardly along a longitudinal axis xx' through the flake, and a width w measured perpendicular to the length l and extending along a transverse axis yy', or, if circular, such flakes may have a diameter d, as shown in the alternative commercially available type unmodified flake 10' in FIG. If the flake is square, the length l and width w will necessarily be the same. It is noted that corresponding reference numerals are used herein for similar features in the flakes of FIGS. 1, 1A and 2.

[0065] Such dimensions, such as width and length (or diameter), are measured between opposing (width-defining) outer edges 12, 13 and (length-defining) 15, 17 of the periphery, also referred to herein as outer edge 14. Outer edge 14 defines a surface area A on the outer surface 16 of each flake. Preferably, surface area A is generally planar, as are most manufactured flakes, but of course it may be somewhat irregular or non-planar if desired. Surface area A in the illustrated prior art embodiment has a first surface area 18 on one side of the flake and a second opposing surface area 19 on the opposite side of the flake, each typically preferably of the same or similar size. Because the flakes are typically very thin and largely two-dimensional in nature, surface areas 18, 19 are typically the same. The outer surface 16 extends around the entire flake including the first and second opposing surfaces 18, 19 and the edges 12, 13, 15 and 17 of the flake, which define the shape of the opposing surfaces 18, 19 and give the flake a thickness t extending along the zz' axis between the two opposing surfaces 18, 19.

[0066] For the flake of FIG. 2, diameter d is measured by a straight line extending from a first point P1 on peripheral edge 14' through a center point CP' of area A' across area A' to a point P2 on edge 14' that is furthest from the starting point.

[0067] It should be understood that the generally planar regions A, A' on the flake may be planar, substantially planar, or only partially planar, and may or may not include surface roughness or features extending from the opposing surface regions 18, 19 of the flake. The lengths and widths may be the same or different. Additionally, the shapes may be somewhat irregular.

[0068] The flakes also generally include a small but measurable thickness t, t', measured along an axis zz' through the flake from one opposing first surface region 18, 18' to the other opposing second surface region 19, 19', perpendicular to the length l and width w (or diameter d). The thickness t is preferably less than either the length l or the width w (and t' is less than the diameter d). Preferred commercially formed prior art flakes that may be used with the improved flakes formed herein or have a similar size and shape have a shortest dimension (l, w or d) in either of the opposing first and second surface regions 18, 19 (18', 19') that is greater than the corresponding thickness t, t' of the respective flake.

[0069] These parameters are illustrated with respect to square and circular prior art flake examples, but it should be understood that other shapes and geometries may be applied, as is commonly known, and further that the thickness of commercially available flakes may vary, including flakes that may be used with the improved flakes formed as herein.

[0070] The thickness of the flakes is important with respect to tensile strength. A thickness of about 140 microns is standard for most commercially available flake products. Thinner composite tapes are commercially available in thicknesses of about 44 microns, but such tapes are significantly more expensive than standard composite tapes. To reduce production costs, composite tapes are manufactured in thicker versions of about 250 microns and even 2,000 microns.

[0071] When making flakes from such composite tapes and similar composites, the thinnest (l or w) flakes available commercially are typically on the order of 1 / 16 inch (about 1588 microns) wide. Flakes as large as 1 inch in length and / or width are also available but are less common. Such flakes can be used to form larger composite parts. The smallest length or width is about 0.20 to 0.25 inches, while other commercially available flakes may be about 1 inch or 2 inches in length or width.

[0072] In a preferred embodiment, the improved polymer composite flakes provided by the methods herein and having peripheral features are about 1 inch in length and / or width, or about 0.5 inch in length and width, with a generally square configuration (aspect ratio of 1:1) being most preferred (such dimensions being measured longitudinally or laterally across the flake from one edge to another). However, other aspect ratios up to 1:16 and other shapes are contemplated for use within the invention herein.

[0073] The improved polymer composite flakes provided by the methods herein for forming articles can be cut or otherwise formed into a variety of shapes, including shapes that are generally triangular, circular, polygonal (preferably having five or more sides), trapezoidal, or parallelograms such as squares, rectangles, or diamonds. By "generally" having a shape or having an "overall shape" is meant that the flakes, when viewed in top or bottom view, have an outer edge or perimeter that defines an area on the opposing surfaces 118, 119, which has an overall geometric configuration encompassed by viewing the perimeter of the improved polymer composite flake at the outer portion of its outer edge 114, or in the case of a circular flake, at the circumferential outer edge 114'. The shape may or may not be a perfect triangle, circle, or parallelogram, for example, but the shape refers to the geometric designation that most closely approximates the overall shape of the area as perceived when viewed two-dimensionally, without specific reference to an outer edge feature formed on one or more portions of the outer edge, as described further below. In the most preferred embodiments, the improved polymer composite flakes have an overall shape that is generally square, rectangular, or diamond shaped in configuration.

[0074] With reference to a standard commercially available flake 10 and FIG. 1, the average surface area was determined by measuring opposing areas 18, 19 across a number of flakes and averaged across a number of such flakes, resulting in an average surface area of ​​approximately 20 mm. 2 From about 650 mm 2and preferably has an average thickness of about 0.05 mm to about 0.25 mm. Similar sized flakes may also be cut from the composite to form the improved polymer composite flakes herein. In a more preferred embodiment, the average surface area is about 20 mm. 2 From about 325 mm 2 , or about 150 mm 2 From about 170 mm 2 , the average thickness may be about 0.1 mm to about 0.20 mm. One skilled in the art will recognize based on this disclosure that such sizes can be varied for various purposes and effects. It will also be recognized that such ranges encompass further ranges within the parameters of the present disclosure.

[0075] Commercially available prior art flakes and the polymer composites from which the improved polymer composite flakes provided by the methods herein are derived have a thickness of, for example, 150 g / m 2 and a resin content of 32% by weight for a polymer such as PEEK. 3 and the density of the polymer, e.g., 1.30 g / cm 3 Knowing that PEEK has a density of 150, this information tells us that the tape thickness in this example is 139 microns, which calculates to 150*(1 / 1.78+(0.32 / 0.68) / 1.3)=139. Other commercial suppliers of composite tapes provide tape thickness designations and resin content. The thickness of the commercially available flakes and the improved flakes provided herein is the same as the thickness of the tape or other composite from which the flakes are cut.

[0076] Existing commercially available composites that can be used to form the improved polymer composite flakes according to the present invention include those from Solvay in the form of thermosets and thermoplastics including phenolic polymers, epoxy polymers, polyetherimides, having long reinforcing fibers such as unidirectional carbon fiber filled APC™ PEKK or PEEK reinforcement tapes, KetaSpire® glass fiber and carbon fiber reinforced flake materials, from Celanese Corporation as Celstran® CFR composite tapes, having unidirectional fibers and including various thermoplastics including polyolefins, polyamides, polyphenylene sulfides, from Evonik Corporation as Vestape® UD Tapes, for example, including PEEK matrix polymer and long carbon fibers, from Greene, Tweed & Co. as Xycomp® DLF®, including flakes formed from thermoplastics including carbon fiber and PEEK, from SABIC in the form of thermoplastic composite tapes such as polyolefins and polyamides with glass fiber and carbon fiber. Examples of carbon fiber reinforced polymers include those available from Solvay, Toray Industries, Inc., Cetex® TC1200 and related products offered as unidirectional carbon fiber reinforced polymers such as epoxy polymers and PEEK. Such examples are not intended to be limiting. In a preferred embodiment, the carbon fiber / PEEK composites may be used in the form of unidirectional tapes from which discontinuous long fiber modified flakes may be cut. Such tapes are available, for example, from Solvay, Toray Industries, Inc., Suprem S.A., Barrday, Inc., Toho Tenax (Teijin Limited), and Victrexplc.

[0077] While commercially available composites may be used, tape-like prepregs having fiber reinforcement may be formed in situ at the same time and / or at the same location as cutting the improved polymer composite flakes according to the methods herein. These may be formed by cutting, stamping, die-cutting, or otherwise forming composites into the improved polymer composite flakes herein having polymer matrix material and long reinforcing fibers as described above.

[0078] The matrix polymer may be a thermoplastic or thermoset material. Preferred thermoplastics for use as the polymer matrix material in the composites and flakes herein include polymer plastics and resins that can be loaded or filled with reinforcing materials and that can flow upon heating.Exemplary thermoplastics include polyolefins (such as polyethylene, polybutylene, polypropylene, and high density polyethylene), poly(acrylonitrile-butadiene-styrene) (ABS), polystyrene, polybutadiene, polyacrylonitrile (PAN), poly(butadiene-styrene) (PBS), poly(styrene-acrylonitrile) (SAN), polybutylene, cellulosics (such as ethyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and cellulose nitrate), polyethylene vinyl alcohol (EVA), polyethylene vinyl acetate, fluoropolymers (melt-processible fluoroplastics including copolymers of tetrafluoroethylene (TFE) and at least one perfluoroalkyl vinyl ether (PAVE) (PFA), and copolymers of TFE and at least one other perfluoroalkylene, such as hexafluoropropylene (FEP)), poly(chlorotrifluoroethylene), polyethyl chlorotrifluoroethylene ( ECTFE), Polyethyltrifluoroethylene (ETFE), Polyvinyl fluoride (PVF) and Polyvinylidene fluoride (PVDF), Ionomer, Liquid Crystal Polymer (LCP), Polyacetal, Polyacrylate, Polyamide (NYLON12, NYLON6, etc.), Polyphthalimide, Polyimide, Polyetheramide, Polyamideimide, Polyphenol, Polycarbonate, Polyester, Thermoplastic Polyurethane, Polyvinyl chloride (PVC), Polyvinylidene chloride, Polyvinyl, Polyphenylene oxide (P PO), polyphenylene ether, polyphenylene ester, polyphenylene ether ester, polyphenylene sulfide, polysulfone, polymethylpentene, polyketone, polyarylene ether ketone, polyarylene ether and polyarylene ether ketone (polyetherketone (PEK), polyetherketoneketone (PEKK), polyetheretherketone (PEEK), etc.), polyethylene chlorinate, polyaramid, thermoplastic biscitraconimide, and the like.

[0079] Matrix materials may include thermoset materials including certain elastomers (such as ethylene propylene diene monomer (EPDM), ethylene propylene rubber (EPR), thermoset polyurethane elastomers, epoxy resins, thermoset biscitraconimide (BCI), bismaleimide (BMI), bismaleimide / triazine / epoxy resins, cyanate esters, cyanate resins, furan resins, phenolic resins, urea formaldehyde resins, melamine formaldehyde resins, phthalocyanine resins, polybenzoxazole resins acetylene terminated polyimide resins, silicones, polytriazines, thermoset polyvinyl esters, thermoset polyurethanes, polytetrafluoroethylene, melamine, polyalkyds, xylene resins. Such polymers may be used alone or in the form of various copolymers or combinations thereof, and combinations may include mixtures, alloys, blends, crosslinked versions of one or more of such polymers and / or one or more of their copolymers.

[0080] Copolymers of each or any of these thermoplastics (polymers formed from two or more monomers in random or block form, or graft copolymers, either of which may have multiple monomer components or reactants) may also be used, whether known or yet to be developed.

[0081] Additionally, such thermoplastics may be further derivatized, provided they are still useful for forming improved flakes, or for forming composites (or combinations of composites) for forming improved flakes by cleaving the composites into improved flakes, and / or may include functional groups (whether terminal and / or on the chain), branched and / or linear backbone structures, additional points of unsaturation along the chain or side groups, etc. Functional groups that may be provided include aryl, ketone, acetylene, acid groups, hydroxyl, sulfur-containing groups, sulfate, sulfite, mercapto, phosphato, carboxyl, cyano, phosphite, halogen, oxygen / ether or ester (which may also be incorporated within the chain or side groups), carboxylic acid, nitrate, ammonium, amide, amidine, benzamidine, imidizole, and the like.

[0082] While these polymers are preferred, this list should not be considered exhaustive and one of ordinary skill in the art will understand based on this disclosure that other thermoplastics can be used in the present invention without departing from its scope.

[0083] Among the above, preferred materials include engineering plastics such as polysulfones, polyimides, polyamideimides, polyetherimides, polyamides, polyphenylene oxides and sulfides, and polyarylene materials such as PEEK, PEK, PEKEKK and PEKK. Fluoropolymers such as those mentioned above may also be used as preferred materials, provided they can be formed into composites to produce the improved flakes herein having reinforcing long fibers, and are flowable at the processing temperatures for forming articles from the improved polymer composite flakes.

[0084] The improved polymer composite flakes can be formed from composites of various polymers and long reinforcing fibers, as described above, but more than one composite may be provided, such that blended improved flakes or improved flakes formed from various composites (or formed from blended thermoplastic and / or reinforcing fiber materials) are employed together and / or blended with existing commercially available flakes in forming an article.

[0085] The composites to provide the improved polymer composite flakes herein may be formed solely from reinforcing long fibers and polymer matrix material, or may be provided therein with one or more additives, including other fillers and / or reinforcing agents known in the art or to be developed. The various additives used include other types of reinforcing fibers or fillers and additives such as pigments, dyes, glass beads or spheres, carbon nanotubes, ceramics, meshes, honeycombs, mica, clays, organic colorants, plasticizers, thixotropic agents, flame retardants, UV absorbers, extenders, stabilizers, silicon dioxide, silica, alumina, talc, short glass fibers, barium sulfate, short PTFE fibers, short TFE copolymer fibers, other reinforcing fibers of various lengths, ribbons or platelets, wollastonite, titanate whiskers, compatibilizers, rheological or thixotropic agents, antistatic agents (which may also be incorporated by the use of functional groups and / or graft copolymers provided in the thermoplastic matrix), chopped or short carbon fibers, and other similar fillers, tribological additives and reinforcing agents. Such additives are preferably present in an amount of about 10% or less of the composite, based on the total weight of the composite (i.e., the total weight of the matrix fibers and long reinforcing fibers) (beyond the thermoplastic matrix material and reinforcing materials present in the composite), but more or less may be used depending on the intended end use. Preferably, such additives are absent or of limited use.

[0086] In the methods herein, where the improved polymer composite flake is formed from one or more composites, once the composite is provided, the improved flake can be formed by cutting, stamping, or chopping the composite to form and provide one or more improved flakes. For example, if the composite is purchased commercially from a manufacturer prior to cutting or otherwise forming the improved flake according to the present invention, this process may be performed prior to obtaining the flake for use in the methods, or a process may be used to form the composite and then cut the composite at the same time and / or at the same location as the improved flake shape is formed. That is, the composite can be used to prepare for a cutting, chopping, or other forming process to form the improved polymer composite flake. Additionally, the improved polymer composite flake may be cut from a polymer composite feedstock, such as a unidirectional tape, and improved using a cutting device as described herein and shown in FIG. 24. This cutting can be done in a separate operation (a constant stock of modified flakes can be made, e.g., prepared and metered out in selected amounts to fill a mold cavity) or the flakes can be cut and modified to drop directly into the mold, e.g., while the mold is being filled.

[0087] The modified polymer composite flake according to the method herein is provided by cutting or otherwise forming at least one peripheral feature on a portion of the outer edge of the flake. Depending on the desired configuration of the modified polymer composite flake, it can have various peripheral edges that may or may not be perpendicular to one another. The peripheral feature can be formed on the entire outer edge, on one or more edges (or extending partially or completely along some or all edges of the flake).

[0088] In embodiments herein, the improved polymer composite flakes may be formed with an outer edge feature having at least two sides, which may be linear or angled sides, or may be formed with a curved edge feature on the outer edge of the flake, preferably on at least a portion of the outer edge of the flake.

[0089] The edge features may be made using any suitable cutting device, including scissors, shears, knives, automated shredding devices, die cutters, saws, cutting blades, drills, grinders, abrasive water jets, and laser beam cutting devices, similar to the devices described herein and shown in Figure 24. Composites can also be used to form improved polymeric composite flakes having long reinforcing fibers and matrix materials as described herein. If desired, a roughened surface can also be provided after the edge features are formed to improve edge properties.

[0090] In some embodiments herein, the angled sides of the peripheral features may be formed to angle toward each other, preferably at one end of the angled end feature. FIGS. 3 and 4 show a modified polymer composite flake 100 herein having an outer edge 114 that defines a surface area A. Opposing outer surface areas 118 and 119 appear on opposite sides of the modified polymer composite flake 100. A peripheral feature 122 is formed on the modified flake's outer surface 116, on a first edge 124 of the modified flake, forming an extended triangular shape in plan view. A similar peripheral feature 122 is formed on a second edge 126. As shown, the second edges are opposed edges. As shown, the angled sides 128a, 128b applied to each peripheral feature define the shape of each peripheral feature (here shown as all the same and having an outwardly extending triangular shape).

[0091] Angled sides 128a, 128b illustrated in Figures 3 and 4 form a first peripheral feature 122a. Angled sides 128a, 128b are angled relative to one another to form an angle α with a vertex. As shown in this embodiment, angled sides 128a, 128b are contiguous and join at contact point 128c to form the vertex V of angle α at the outermost tip of triangular shaped peripheral feature 122a. 1Since each feature is the same and each edge feature is also contiguous, the angle α also represents the angle between edge features that extend towards each other. Contiguous features form a single contact point P 3 (which is the apex of the inwardly extending ends of the peripheral features). The angle α is preferably an acute angle, as shown in Figures 3 and 4. In embodiments herein, the angle α may range from about 5° to about 120°. The angle α may also be from about 20° to about 90°, and more preferably from about 20° to about 60°. In even more preferred embodiments, the angle α may be from about 30° to about 60°.

[0092] The modified polymer composite flake may have one or more (i.e., two or more) such peripheral features cut to be on an edge along the outer periphery of the modified polymer composite flake and formed on the outer surface. The flake is cut or formed to have a peripheral feature on at least a portion of the outer periphery of the modified polymer composite flake, and cut to extend across the thickness of the flake in the z direction and also in the xy plane, such that the feature spans opposing outer surface regions 118, 119 along the thickness t of the modified flake 100. Although the peripheral feature can be formed to extend only partially through the thickness of the flake, or angled wedge-like across the thickness so that it is gradual in two planes, forming the peripheral feature to span the thickness of the flake as shown is more preferred and easier to manufacture.

[0093] The peripheral features may be formed such that they are not triangular in plan view as shown in Figures 3 and 4, do not have continuous sides, and do not contact each other at a single contact point when the pattern is continuous. Figure 23 provides one example of such an alternative embodiment of a modified polymer composite flake 100', comprising two peripheral features 122' having angled sides 128a', 128b' that form a trapezoid shape for the peripheral features 122' at an edge portion 124' on an edge 114' of the modified flake 100' that extends through its thickness. The angled sides of each edge feature are not triangular at their outer ends, since they are angled toward each other and do not connect at a vertex. The angled sides are angled toward each other and form a vertex V( projected outwardly of the ends of the angled sides, as shown in Figure 4. 2 ) to form an angle α' with respect to each other. Sides 128a', 128b' are not continuous. Additionally, outer edge 122' is for a pattern. The patterned features are connected by straight edges 130' and are configured in a pattern such as a "dovetail" design. Also, note that in a preferred embodiment, the pattern on one edge is an inverse pattern of the opposing edge such that the outwardly extending trapezoids of the first edge are aligned longitudinally (preferably in the fiber direction) with the gaps in the inwardly extending trapezoids of the opposing edge. This arrangement provides the optional advantage of being able to keep the fiber length constant from one end of the pattern of outer edge features to the other.

[0094] With respect to Figures 3 and 4 (and the flakes shown in the embodiment of Figures 3A-3C), a plurality of peripheral features 122 are provided on two opposing peripheral edges 124, 126 of a total of four peripheral edges 124, 126, 130, 132 on the illustrated modified flake, which is a modified polymer composite flake formed to have opposing parallelogram-shaped outer surface areas, and in this embodiment, the modified polymer composite flake is formed as a square flake having peripheral features. Each of the peripheral features 122 on the outer periphery of the outer surface is created on either edge 124, 126 and is formed to be contiguous with one another and has a single contact point P 323 (unlike the feature edges of FIGS. 7A, 7B, 16, 19, 22-23 which are connected by a straight edge shown as 130' in FIG. 23).

[0095] In Figures 3 and 4, the continuity of the angled edges relative to one another provides a zigzag pattern Z at edges 124, 126. Four peripheral features on each of lateral edges 124, 126 (modified flake 100) are shown in Figures 3 and 4 (and in Figure 3A), which are used in Examples 1, 2, and 3 herein based on the configurations of Figures 3 and 4, each having an angle α of about 30° between successive peripheral edges. A similar design is also shown and used in Example 2 (Figures 3B and 3C), which shows similar modified flakes 200, 300, respectively, having a similar configuration and four peripheral features as modified flake 100, but with angles α of 60° in Figure 3B and 90° in Figure 3C.

[0096] Figures 5A, 5B and 5C show modified polymer composite flakes 400, 500, 600, respectively, similar to those shown in Figures 3-3C and 4, respectively, used in the samples of Example 2, but with eight perimeter features and angles α of 30°, 60° and 90°, respectively, each also having perimeter features on two opposing edges of the four edges shown for modified flakes 400, 500 and 600.

[0097] Figures 6A, 6B, 6C, 6D and 6E also show further improved polymer composite flakes 700, 800, 900, 1000 and 1100, respectively, similar to the flakes of Figures 3-3C and 4, but with 12 outer edge features and angles α of 30°, 60°, 90°, 5° and 15°, respectively. These flakes are also used in Example 2 herein.

[0098] In some embodiments, the peripheral features form a pattern, but are configured such that they do not connect at a common contact point, as the angled peripheral features mentioned above typically do. If the peripheral features are shapes that are not completely corner-free, parallelograms, or other shapes in which the angle α is projectively measurable or 0°, a pattern may be formed in which consecutive peripheral features in the pattern are connected by substantially straight edge portions. This is shown, for example, in the stepped peripheral feature configurations of Figures 7A and 7B (modified flakes 1200, 1300), as well as the configurations shown in Figures 16, 19, and 21-23.

[0099] In addition to the stepped or "slotted" perimeter configurations of Figures 7A, 7B, and 22, further examples of patterns and unique shaped perimeter configurations are depicted and described herein. Figure 14 shows a further triangular edge feature, with ten consecutive triangular features on two opposing edges of the illustrated flake. Figure 15 shows a parabolic pattern with four parabolic perimeter features on opposing edges. Figure 16 shows a variation of the rectangular slots of Figures 7A, 7B, and 22 in which the perimeter features are angled parallelograms. Figure 17 shows a curved perimeter pattern. Unlike the parabolic features of Figure 15, where the sides of the features are completely curved and join at a curved end, the perimeter features of Figure 17 have straight sides, but the ends of each feature join in a semicircle, so that each feature appears in the shape of the end of a tongue depressor. 18 and 20 are examples of flakes having only one edge feature on the outer edge. Such a feature is located on each of two opposing edges. In FIG. 18, the edge feature is triangular, while in FIG. 20, the edge feature is a single fully curved feature. In FIG. 19, there is an example of using two different edge feature shapes that alternate in a pattern, one edge feature shape is rectangular, while the other alternating edge feature shape is a bullet shaped feature with slightly curved sides and connecting at a slightly curved end. Each feature is connected in the pattern by a straight edge. FIG. 21 provides a complex edge feature with an arrowhead shape. The arrowhead includes a rectangular base and a triangular arrowhead end, with the angled side of the triangle providing the apex end. FIG. 22 is an example of a configuration with slots like FIG. 7A and FIG. 7B, but provides only three slot features on each of the two opposing edge features of FIG. 22. FIG. 23 shows an example of a trapezoidal edge feature as further described elsewhere herein.

[0100] It is noted in each configuration that, as a preferred example, a pattern is provided on opposing edges such that an "inverse" pattern appears, where an outwardly extending edge feature on one outer side is aligned longitudinally (preferably in the fiber direction) with a corresponding recess on the opposing edge surface that extends inwardly into the flake, so that the fibers within the flake are of a constant length across the flake in the fiber direction, regardless of the length of the edge feature itself.

[0101] It is also possible to form modified polymer composite flake surface area shapes that vary as described above, such as the circular flakes shown in Figure 2 with all or a portion of edge 14' provided with such peripheral features as described above, as well as elliptical or oval shaped flakes that can be formed as modified polymer composite flakes as well. Triangular or other parallelogram or trapezoidal shaped flakes, i.e., flakes having three or more edges, and polygonal flakes of five or more edges may also be made, with at least two or more of the edges of each of these types of modified flakes provided with peripheral features.

[0102] As shown in the various edge configurations of Figures 3 through 3C, and 4, as well as Figures 5A through 5C, 6A through 6E, 7A through 7B, and 14 through 23, it is possible that the long reinforcing fibers in the flakes F extend in one direction and through at least one flake in a first direction D, as best shown in Figure 3A, and that edge sections selected to have edge features, including those that form zigzags and other patterns, may extend in a second direction D along one or more of the edge sections. 2 , direction D 1 . . .

[0103] As shown in FIG. 3A, for example, the reinforcing long fiber F is aligned in the same direction D as the length dimension along the axis xx′ of the flake 100. 1 The two opposing edges 124, 126 shown have peripheral features 122 each extending along the edge substantially its entire length and in a direction D, as shown. 1 1, the flake 100 extends in a width direction D along the axis yy' of the flake 100 at an angle β generally perpendicular to the2 , which extend from the body surface region of the improved flake, the outer edge features of which are preferably defined by edge portion A, in a direction D 1 However, the angle β may be varied for different flake designs, such as those with angled sides (e.g., triangular, polygonal, or trapezoidal flakes), or to provide a modified flake having, for example, a generally parallelogram shape with four sides, and a fiber extending in the direction D. 1 This may involve additional edge features simply being created in the flake when cutting, stamping, chopping or otherwise forming the improved polymer composite flake by cutting at least one side cut formed at an angle relative to the angle of.

[0104] The use of angle β is optional, i.e., the edge feature and / or its zigzag pattern is preferably aligned with the fiber direction D of a flake having fibers extending in one direction. 1 In the case where the modified flakes are provided on the outer edge of the modified flakes that run parallel to the fiber direction D, or the modified flakes do not have fibers that run in one direction (such as a woven structure, or more random or angled fibers). When providing fibers that run in one direction, the outer edge features and / or the portion of the outer edge that has a zigzag or other pattern may be provided in a manner that is parallel to the fiber direction D. 1 It is preferable that the angle is angled with respect to the

[0105] Fibers are not shown in Figures 1-4 and 14-23, but when viewing the modified flakes as shown, it should be understood by one skilled in the art that the drawings of the modified polymer composite flakes shown are for illustrative purposes of construction and to show the shape and configuration of the flake 100 both before modification (see Figures 1, 1A and 2) and after modification (see Figures 3, 4 and 14-23) by emphasizing dimensional requirements. Unmodified flakes are known in the art and one skilled in the art will understand based on this disclosure that fibers will be embedded and impregnated within the composite from which the modified flakes are formed and within the modified flakes after they are cut from the composite. They may extend in one or more directions, and preferably extend in one direction as described elsewhere herein.

[0106] The peripheral features of the improved polymer composite flakes herein provide articles formed therefrom with enhanced tensile strength, and / or increased impact resistance, especially at high speeds, and / or higher fracture limits due to reduced stress concentrations at the edges of the flakes by forming edges having peripheral features singly, in groups, and / or in zigzag and other patterns.

[0107] Applicant has used the Inglis equation to help estimate the stress at the edge of a composite tape. In the Inglis equation, the stress may be approximated as the stress at the edge of a hole in the composite, where the hole has an elliptical shape and the width of the hole approximates the thickness of the unidirectionally aligned fiber reinforced composite. The Inglis equation expresses the relationship of the stress for such a hole as the following equation (I), where the hole parameters a and b approximate the width and length of the hole, respectively, and σ max / σ is the stress concentration factor, while the composite is subjected to axial stress σ in the b direction, the edge of the hole σ max The maximum strength (stress) is applied.

number

[0108] This analogy compares the stresses observed near a hole in a plate when it is under tension. If the hole is circular, the stress concentration reaches three times the stress applied to the plate. If a discontinuous long-fiber plate under tension is considered relative to a standard flake without edge modification, the mechanical properties (strength and stiffness) drop to practically zero at the edge of the flake in the fiber direction.

[0109] For example, in a 140 micron thick flake, the edges of the flake represent "laminations" in the thickness of 20 or more fibers (assuming a diameter of about 7 microns), all cut to the same length with a blunt blade, so they all end abruptly. The surrounding flakes can bridge the edges of the flake in forming the molded article, but for a distance of about one flake thickness there are no fibers, only polymer. The strength and stiffness in the fiber direction of the composite flake is about 2130 MPa and 135 GPa, respectively, which is used for commercial carbon / PEEK flakes. The strength and stiffness of the PEEK (the polymer surrounding the edges of the flake) used for such flakes is about 100 MPa and 3.7 GPa, respectively. With strength and stiffness more than 20 times lower, they can approach zero properties. That is, even though there are no actual "holes" at the ends of standard commercial carbon fiber / PEEK flakes, they are resin-rich areas, so in some sense they resemble holes from a strength and stiffness standpoint.

[0110] Attempts to make the flake thinner would, by analogy with the Inglis equation, be able to consider the analogical hole as an ellipse, so the thickness (a axis of the hole) would decrease, which would reduce the stress concentration factor. However, in the present invention, by providing an improved edge feature, for example to provide a zigzag-like pattern, there would be an essentially gradual edge, or smooth transition from a location of high carbon fiber properties within the flake to the outwardly extending end of the outer edge feature (like the point of a triangular feature) where the properties are again close to zero. Again by analogy with the Inglis equation, it is as if the axis b of the ellipse were to increase, decreasing the stress concentration factor. Thus, rather than thinning the flake to increase strength, the thickness would remain the same, the length and amount of fiber would remain the same, and the edges would become gradual while reducing the stress concentration factor. This would result in a less dramatic transition between the zero properties at the very outer edge and the high level of strength properties within the flake, making the transition more gradual. Changing the a in the equation could be more effective in some cases, but would not be as cost-effective from a manufacturing standpoint.

[0111] Applicant has already attempted to use various discontinuous long reinforcing flakes of different lengths in Applicant's U.S. Patent No. 10,160,146. However, although a good molded article and good isotropy were obtained, the strength of the final molded article formed from such composite tape was not sufficiently improved. Based on Applicant's data, Applicant's theory is that the "length" parameter b, when given to each modified flake, was important not only in the isotropic enhancement in strength, but also in the ultimate increase in strength of the article formed from the modified flakes. Not only was the strength significantly improved, but the impact resistance, especially at high speeds, and fatigue limit were also increased. Usage example

[0112] In further exploring the impact of the invention herein, it has been further discovered that by modifying or altering the number of peripheral features and the angle or nature of the edges of the peripheral features, varying the features, the best impact can be achieved in terms of improving the strength and / or fracture threshold and / or high speed impact resistance of the resulting article formed from the modified polymer composite flakes. This is borne out in the following examples. Each of the examples herein is intended to be illustrative of the invention, but should not be considered limiting.

[0113] Example 1

[0114] In the following examples, unidirectional composite tapes with continuous long reinforcing fibers running along their length were used. Specifically, three types of polyetheretherketone composite tapes commercially available from Solvay, Barrday, and Tencate (Toray) were tested. Samples were made with AS4 carbon fiber (C / PEEK) (samples A, B, and C) that were cut into straight square flakes measuring 0.5 inches by 0.5 inches on the exterior surface area defined by the edges of the flakes and looking like the prior art flakes in FIG. 1. The improved polymer composite flakes were made of the same material and had a zigzag pattern as shown in FIG. 3B and an exterior configuration as shown in FIG. 3 and FIG. 4 on two opposite edges. In one of the two opposing edges, the zigzag pattern included four outwardly extending peripheral features with angled sides that formed vertices (hence appearing triangular) with an angle α of 30° between consecutive pairs of peripheral features. In the other, second opposing edge, the zigzag pattern was positioned such that where the angled edge features extended outwardly on the second opposing side, their vertices were axially aligned with consecutive connection points between two consecutive edge features on the first side. Thus, the second edge included three triangular edge features identical to those formed on the first edge, with an angle of 30° between consecutive features (angle α), but at the end of the second edge, there were two narrow partial edge features spaced 30° apart from each of the three consecutive features. This partial feature, like the remainder of the pattern, formed approximately half of a complete edge feature, thereby providing the advantage of a total of four outer edge features, each having two sides with an angle between them. The outer edge features formed the pattern on each of the opposing edges and extended the length of the edge with a flake dimension of 0.5 inches. The carbon fibers extended in a direction generally perpendicular to the two opposing edges of the outer edge features (angle β was 90°).The length between opposing sides measured directly across the flake from one opposing side to the other was approximately the same length along the two opposing outer edge edges with the outer edge features due to the pattern formed on the opposing sides, thus maintaining a continuous fiber length but providing a gradual (transitional) exposure of the fiber ends due to cutting the pattern into the flake.

[0115] The composite tapes used were each 0.14 mm nominal thickness and contained approximately the same fiber volume of 61%. The flake material of the modified polymer composite flakes was molded into 0.1 inch thick plates measuring 12 inches by 12 inches using a compression molding process and cut into 1 inch wide "dogbone" shaped samples at the gauge section. A minimum of 20 samples of each configuration were tested using the tensile test method of American Standard Test Methods (ASTM) Standard No. ASTM D3039-17.

[0116] The molding process included cutting the unidirectional tape to form flakes using a device capable of chopping into reproducible flake shapes. The required amount of flakes was weighed out and filled into a square mold cavity with dimensions of 12 inches by 12 inches by manually spreading the flakes evenly (it could also be filled by a robotic system). The mold was heated to about 400°C in a hot press, but the processing temperature could be from about 360°C to about 430°C. A pressure of about 100 bar was applied to the material. Processing pressures of about 60 bar to about 150 bar may be used for the material. The material was then cooled at the same pressure in a cold press. The resulting plate was about 0.1 inches thick and was processed into seven dogbone-shaped samples, each 1 inch wide.

[0117] FIG. 11 shows that when the flakes were modified, the tensile strength of the articles formed from the flakes increased regardless of the source of the raw material. All three sources of material showed similar increases of about 30% to about 40% when modified over unmodified flakes formed in the same composite with a square flake configuration as in FIG. 1. The graph identifies the samples in the unmodified state as "0-0-A," "0-0-B," and "0-0-C," from which molded articles were made from unmodified flakes without edge features. Such commercial samples were square with a configuration as in FIGS. 1 and 1A. The modified samples have the designation of the commercial sample (A, B, or C), but note the total number of edge features (N) used in the modified flake on two opposing edges, and the angle between the edge features provided, e.g., Sample A had four edge features located on each of two opposing edges, which extended the length of the edge of the square surface area defined by the edges, the edge features were triangular and continuous, and the angle between each feature was 30°, thus designated N4-30-A. An unmodified version of Sample A was designated 0-0-A.

[0118] Example 2

[0119] In this example, two types of commercially available composite (C / PEEK) unidirectional tapes with AS4 carbon fiber were used to make various inventive samples. The tapes were from Solvay and Tencate (Toray). The number, shape, and angle of the outer edge features of the inventive samples of modified polymer composite flakes were varied. The flakes were formed for molding by chopping the unidirectional composite tape such that the modified flakes formed were 0.5 inch by 0.5 inch modified flakes with long fibers in them from the tape.

[0120] In addition to the inventive samples, comparative samples of the prior art were also used. Comparative sample D was an unmodified flake having a square surface area defined by an outer edge of 0.5 inch by 0.5 inch, with a design as shown in Figure 1. Comparative sample E was a bias cut flake with straight edges, cut with bias edges cut at a 45° angle.

[0121] Thirteen different inventive samples were made, each with varying edge features and / or varying numbers of features. All inventive samples were similarly oriented in that the edge features were located on two opposing edge portions, the modified flakes were generally parallelogram-shaped with edge features formed as described above, and the edge portions with the edge features were positioned to extend at an angle β of 90° relative to the direction in which the fibers of the modified flakes extended.

[0122] Some of the inventive samples of this example were formed similarly to the modified polymer composite flakes of the inventive samples of Example 1 herein, i.e., had "triangular" peripheral features forming a zigzag pattern and included on opposing peripheral edges with an angle α between successive peripheral features. In this design, the "teeth" were staggered on opposing sides such that the apex of the peripheral feature on a first opposing side was aligned along the fiber direction across the flake with the contact point between two successive peripheral features on a second opposing side of the modified flake such that the fiber length was generally constant along the modified flake.

[0123] These samples were named by the number of outwardly extending edge features (in this case, "teeth") with reference to the angle α between successive edge features. For example, in the first inventive sample, sample 30-4, "30" represents the angle α between edge features and "4" represents the number of edge features on each of the opposing edges. Thereafter, other inventive samples having triangular edge features were altered in angle and number of edge features and named accordingly.

[0124] The inventive samples were also formed using rectangular shaped peripheral features in a "step cut" variation. Because the features were rectangular, their sides were joined by straight segments, with no "apex" formed in the peripheral features such that the angle α between them was 0°. Each feature was not connected to the next peripheral feature at a single point, as with triangular peripheral features, but instead was connected by a substantially straight edge segment having a width equal to the width of the stepped peripheral feature. Each such improved flake had a series of rectangular "teeth" and was cut to appear elongated. The fibers also ran in the direction of the feature such that the angle β was 90° and perpendicular to the extension direction of the opposing profile end, including the profile end feature. The pattern had a staggered arrangement of similarly aligned features on each opposing edge feature, such that an outwardly extending rectangular peripheral feature on a first peripheral edge was aligned with the space between two outwardly extending peripheral features on a second peripheral edge. These samples are identified, for example, as Sample 6x2, where "6" is the depth of the cut (mm) and "2" is the width of the outer edge of the rectangle (mm).

[0125] For each configuration, the same modified flakes were made using commercially available tape material and the data from the various materials was averaged to provide the data herein.

[0126] Figures 3B-3D, 5A-5C, 6A-6E and 7A-7B represent the inventive samples of improved flakes, designated as samples 30-4, 60-4, 90-4, 30-8, 60-8, 90-8, 30-12, 60-12, 90-12, 5-12, 15-12, 6x2 and 6x1, respectively, in the table of Figure 9. Such samples are also represented in their respective order in Figures 3A-3C (flakes 100, 200 and 300), Figures 5A-5C (flakes 400, 500 and 600), Figures 6A-6E (flakes 700, 800, 900, 1000 and 1100) and Figures 7A-7B (flakes 1100 and 1200).

[0127] 8A and 8B show comparative samples D (square cut not enhanced by edge features) and E (bias cut not enhanced by edge features).

[0128] Each of the inventive and comparative samples was tested using ASTM D3039-17. Figure 9 shows the average tensile strength of the articles formed from all of the improved flake shapes. In testing, all of the inventive samples having improvements to provide edge features showed an increase in tensile strength after providing the improved edge features.

[0129] Comparative Sample E (bias cut) showed a slight increase in strength compared to Comparative Sample D. It is known that similar strengthening effects can be achieved by using longer fibers (and therefore longer flakes in the fiber direction), however, it has been found that longer fibers are often more difficult to process.

[0130] In contrast, the inventive samples and modified polymer composite flakes used herein with modified edges from the peripheral features maintained the same fiber length as the original flakes and maintained the ease of processing of the square flakes, while benefiting from enhanced strength. FIG. 10 further shows that the deeper the edge modification in the inventive samples tested, the greater the increase in tensile strength. The articles formed show that the average tensile strength of the flakes formed in the inventive samples is higher than would be expected from the unmodified flakes, indicating that the modification and strength properties can be improved depending on the configuration or number of peripheral features and / or the adjustment of the angle or spacing between the peripheral features. Thus, more or fewer peripheral features, modifications of the shape or angle, and the depth of the cut of the modified edge features into the flakes can be employed and modified to create articles from modified flakes using the methods herein, each of which shows good results, but can be adjusted to achieve the optimal modification or strength level for a given polymer matrix material and intended end use.

[0131] Example 3

[0132] The effects of hail are of particular concern in the aerospace industry, as hail can strike any exposed part of an aircraft, at travelling speeds of up to 250 m / s. The ability of materials to withstand the impact of particularly high-velocity projectiles is important to provide suitable composites that can be used in the manufacture of aircraft. Impact resistance is also important in areas subject to large hail and sleet from strong storms with high velocity winds, which can cause significant property damage and injury.

[0133] Impact resistance, especially at high speeds, can be evaluated by studying the impact of artificial aragonite on coupons and real parts. For this purpose, and to evaluate the response of materials formed from the modified polymer composite flakes according to the present invention, modified flakes were formed using inventive sample 30-4 of Example 2, i.e., flakes measuring 0.5 inches by 0.5 inches were formed in a square configuration from a 0.5 inch wide flake, and such flakes included a total of four edge features as cuts (aligned so that an outwardly extending edge feature on a first edge is offset with a common point between two consecutive edge features on the opposite edge) with consecutive edge features being triangular in shape and with an angle of 30° between them. In this example, comparative flakes with unmodified edges (without edge features) such as comparative sample D of Example 2 were also used.

[0134] The modified polymer composite flakes were molded using the molding process described above to form plates measuring 12 inches by 12 inches and 0.15 inches thick. Each plate was cut in half to form two 12 inch by 6 inch plates. The plates were placed into the test fixture shown in Figure 12. Each plate was clamped at both long edges with rubber bolster clamps spaced 1 inch apart, leaving a 4 inch width between the clamps free. Each plate was tilted 30° from the horizontal. A 50 mm diameter aragonite stone was impacted against the center of the plate on a horizontal trajectory at a temperature of -18°C with a velocity of 100 to 300 m / s.

[0135] After impact, the plates were inspected and damage was rated as either (i) no visible damage, (ii) visible damage, and / or (iii) liberation of material. FIG. 13 is a graphical representation of the data, with each test represented on the illustrated chart by a dot. The results showed that the modified polymer composite flakes provided a significant improvement over the straight cut flakes. When plates formed from modified flake samples were compared to plates formed from unmodified flake comparison samples, the speed at which damage occurred increased by approximately 75 m / s, and liberation of material did not occur until approximately 100 m / s higher. Example 4

[0136] To further evaluate the invention with respect to fatigue resistance, unnotched tensile test samples were prepared and subjected to fatigue cycles at a stress ratio R=0.1. Figure 25 shows the results of this test, where the applied stress level (MPa) is plotted against the number of cycles applied until the specimen broke. Some samples completed the run without breaking, and are indicated by separate markers.

[0137] In this example, a test sample (Comparative Example X) was made using unmodified flakes with no edge features and a test sample (Invention Sample Y) was made using the flakes formed in Example 1. Both types of flakes were cut from the same carbon and PEEK (C / PEEK) unidirectional tape. The modified flakes used to form Invention Sample Y were modified with four "triangular" edge features ("teeth") forming a zigzag pattern with a 30° angle α between each feature and the square shape (0.5 inch dimension), as in Example 1. The features were on two opposing edge edges with an angle α between successive edge features. The fibers passed between the edge features and were oriented perpendicular to the direction of extension of the edge features (i.e., the 90° angle β as described herein above). In the design, the teeth were staggered on opposite sides such that the apex of an edge feature on a first opposing side was aligned along the fiber direction across the flake with the contact point between two consecutive edge features on a second opposing edge of the improved flake such that the fiber length was generally constant along the improved flake.

[0138] The fatigue lives of Comparative Sample X and Inventive Sample Y were evaluated using unnotched tensile specimens formed from unmodified (Comparative Sample X) and modified (Inventive Sample Y) flakes. The data in FIG. 25 shows where the various unnotched tensile specimens broke or completed. A linear fit of each set of data points is shown in FIG. 25 for both Samples X and Y. Based on the linear fits, it is shown that there is a significant increase in high cycle fatigue life of about 59% when the modified flakes are used instead of the standard flakes, even when the same composite is used.

[0139] Example 5

[0140] In this example, unmodified and modified flakes formed according to Example 4 were used to prepare samples for high velocity hail impact testing (i.e., Comparative Sample X and Inventive Sample Y). Comparative Sample X composite samples were formed using unmodified flakes and Inventive Sample Y composite samples were formed using modified flakes, each employing a square shape with 0.5 inch dimensions. A further inventive composite (Inventive Sample Z) was produced using modified flakes made from the same composite as Inventive Sample Y, but had a rectangular shape with a length (dimension along the fiber direction) of 1.0 inch. The orthogonal cross-machine direction had the same width dimension (0.5 inch) as Inventive Sample Y. Edge features had the same features as Inventive Sample Y and were located along the edges extending in the cross-machine direction.

[0141] The apparatus and method of Example 3 (including the parameters noted therein) were used to test samples of Comparative Sample X, as well as Inventive Samples Y and Z. The impact response when the plates were examined is shown in FIG. 26, and damage was assessed as either (i) no visible damage, (ii) visible damage and / or (iii) material release. Similar to the results shown in FIG. 13 of Example 3, the results shown demonstrate that the modified composite flake of Inventive Sample Y provided a significant improvement over the unmodified (straight cut) flake of Comparative Sample X. The speed at which damage occurred in Inventive Sample Y was significantly increased over Comparative Sample X, with no material release occurring until about 225 m / sec. Inventive Sample Z performed slightly better than Inventive Sample Y in that visible damage occurred and no obvious material release was observed in the samples tested. Inventive Sample Z had significantly better high speed impact resistance compared to Comparative Sample X. The results demonstrate that longer flakes provide even greater improvement and that the beneficial properties provided by the gradual edge in the edge characteristics of the improved flakes are cumulative of the benefits obtained by employing longer fibers.

[0142] As the above disclosure and examples show, articles formed from the improved polymer composite flakes and / or using the methods herein can be of various types and can vary depending on the composite selected, for example, a plurality of improved polymer composite flakes as described herein can be used to form devices, components or parts that can be used in a variety of end uses. For example, articles can be formed as strong, lightweight aircraft parts, medical devices, containment shells and / or components for use in high temperature and pressure end uses (such as semiconductor, fluid processing or underground oil field conditions). Aircraft parts such as brackets, covers, fairings, and cabin side wall attachments can also be formed. Other end uses include devices, parts and components used in the robotics, automotive, semiconductor and sports industries, such as robot legs, automotive damper casings, wafer handling tools for semiconductor processing, bicycle parts, and the like.

[0143] Such articles can be formed by heat molding or curing a plurality of modified polymer composite flakes provided according to the methods herein and formed directly into an article, or by blending modified polymer composite flakes with other types of flakes for different effects, depending on the type of matrix polymer. If a second or additional type of flake is used, such flakes may be modified according to the methods herein or may be unmodified flakes. Furthermore, when a second or additional type of flake is used with the modified flakes herein, the polymer matrix material and / or reinforcing fibers may be the same or different from those of the modified flakes with which they are combined. Preferred molding conditions are as described above.

[0144] As the examples demonstrate, the invention herein also provides a method for increasing one or more of the average tensile strength and / or impact resistance, particularly high velocity impact resistance, for an article formed using modified polymer composite flakes having peripheral features, compared to an article formed from a standard unmodified composite flake formed having a polymer matrix material extending through the flake and reinforcing long fibers therein. The improvement results from providing a portion of the peripheral edge of the modified polymer composite flakes provided herein with one or more peripheral features as described herein above, using techniques as described herein above. The fatigue limit of such articles can also be increased using the modified flakes and methods herein.

[0145] Those skilled in the art will appreciate that changes could be made in the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that the invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the invention as defined by the appended claims.

Claims

1. 1. A method for providing improved polymer composite flakes for use in forming an article, comprising: (a) providing a composite having at least one polymer matrix material and long reinforcing fibers of a first fibrous material extending through the polymer matrix material; (b) forming at least one flake from the composite, the at least one flake has an outer surface with an outer edge; a portion of the outer edge configured to provide at least one outer edge feature on the outer edge of the at least one flake, thereby providing an improved polymer composite flake; A method comprising:

2. The method of claim 1 , further comprising forming the at least one flake by cutting the composite to form the at least one flake.

3. The method of claim 2 , wherein the at least one flake is cut by a cutting device.

4. The method of claim 1 , wherein the composite is in a form selected from a tape, a plate, and a sheet.

5. The method of claim 1 , wherein the long reinforcing fibers in the composite extend in one direction.

6. The method of claim 5 , wherein the long reinforcing fibers in the composite are continuous long reinforcing fibers.

7. 2. The method of claim 1, wherein the composite is in the form of a tape and the long reinforcing fibers are continuous long reinforcing fibers extending in one direction.

8. The method of claim 1 , wherein the at least one perimeter feature has at least two angled sides.

9. The method of claim 8 , wherein the at least two angled sides of the edge feature are angled toward one another at an angle of about 5° to about 120°.

10. The method of claim 9 , wherein the at least two angled sides of the edge feature are angled toward one another at an angle of about 20° to about 90°.

11. The method of claim 10 , wherein the at least two angled sides of the edge feature are angled toward one another at an angle of about 20° to about 60°.

12. The method of claim 11 , wherein the at least two angled sides of the edge feature are angled toward one another at an angle of about 30° to about 60°.

13. The method of claim 12 , wherein the at least two angled sides of the edge feature are contiguous and together form a vertex of the angle at a point of contact between the at least two angled sides.

14. The method of claim 8 , wherein there are multiple edge features.

15. 15. The method of claim 14, wherein the at least two angled sides of each edge feature are contiguous and together form an angle apex at a contact point between the at least two angled sides, and at least two edge features of the plurality of edge features are also contiguous such that a portion of the edge having the at least one edge feature has a zigzag pattern.

16. the periphery of the at least one flake has at least three peripheries; The method of claim 15 , wherein at least two of the outer edges have the zigzag pattern.

17. the long reinforcing fibers in the at least one flake extend in one direction and extend through the at least one flake in a first direction; The method of claim 15 , wherein the outer edge having the zigzag pattern extends in a second direction that is angled relative to the first direction.

18. 18. The method of claim 17, wherein the angle between the second direction and the first direction is approximately 90 degrees.

19. 20. The method of claim 17, wherein the angle between the second direction and the first direction is from about 60 degrees to about 90 degrees.

20. the at least one edge feature is configured to have a shape selected from a triangular shape, a parabolic shape, a parallelogram shape, a bell shape, a bullet shape, an arrowhead shape, and a trapezoid shape; The method of claim 1 , wherein when there is more than one edge feature, each edge feature may be the same or different.

21. The method of claim 20 , wherein the at least one perimeter feature is a parallelogram having a rectangular shape.

22. 21. The method of claim 20, wherein the portion of the periphery having the periphery features includes two or more periphery features, the periphery features together forming a pattern.

23. 23. The method of claim 22, wherein the at least one flake has four outer edges, two of which are opposing outer edges, each of the two opposing outer edges having the pattern formed thereon such that the pattern extends along substantially all of the two opposing outer edges and such that the distance between the two opposing outer edges measured longitudinally across the at least one flake remains substantially the same throughout the pattern.

24. 10. The method of claim 1, wherein the polymer matrix material is a thermoplastic and is one or more of polysulfones, polysulfides, polyimides, polyamideimides, polyamides, polyarylene polymers, fluoropolymers, and combinations and copolymers thereof.

25. 25. The method of claim 24, wherein the polymer matrix material is a polyarylene polymer that is one or more of polyetherketone, polyetheretherketone, polyetherketoneketone, and combinations and copolymers thereof.

26. 25. The method of claim 24, wherein the polymer matrix material is a fluoropolymer that is at least one of a copolymer of tetrafluoroethylene and at least one perfluoroalkyl vinyl ether, a copolymer of tetrafluoroethylene and at least one other perfluoroalkylene, polychlorotrifluoroethylene, ethylchlorotrifluoroethylene, ethyltrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, and combinations and copolymers thereof.

27. 2. The method of claim 1, wherein the polymer matrix material is a thermoset polymer and is one or more of thermoset elastomers, epoxy resins, thermoset biscitraconimides, bismaleimides, bismaleimide / triazine / epoxy resins, cyanate esters, cyanate resins, furan resins, phenolic resins, urea formaldehyde resins, melamine-formaldehyde resins, phthalocyanine resins, polybenzoxazole resins, acetylene terminated polyimide resins, silicones, polytriazines, thermoset polyvinyl esters, thermoset polyurethanes, polytetrafluoroethylene, melamine, polyalkyds, xylene resins.

28. 2. The method of claim 1, wherein the long reinforcing fibers in the at least one flake are one or more of inorganic fibers, ceramic fibers, glass fibers, graphite fibers, carbon fibers, thermoplastic fibers, thermoset fibers, and combinations thereof.

29. the outer edge of the at least one flake defines a surface area on the outer surface of the at least one flake having an overall shape that is generally a triangle, a polygon having at least five sides, a circle, a parallelogram, or a trapezoid; The method of claim 1 , wherein the at least one perimeter feature is formed on at least one edge of such surface region shape.

30. 30. The method of claim 29, wherein the surface area defined by the perimeter is a parallelogram selected from a square, a rectangle, and a rhombus.

31. a plurality of flakes, each having a surface area defined on the outer surface of the flake by the outer edge of the flake and a thickness measured along the outer edge of each flake in a plane perpendicular to the surface area of ​​the flake; 30. The method of claim 29, wherein the plurality of flakes has an average outer surface area of ​​about 20 square millimeters to about 650 square millimeters and an average thickness of the plurality of flakes is about 0.05 mm to about 0.25 mm.

32. the average outer surface area of ​​the plurality of flakes is from about 150 square millimeters to about 170 square millimeters; 32. The method of claim 31 , wherein the average thickness of the plurality of flakes is from about 0.1 mm to about 0.20 mm.

33. 10. The method of claim 1, wherein when an article is formed using a plurality of said modified polymer composite flakes having said peripheral features, said article formed has an average tensile strength that is at least about 30% greater than the tensile strength of an article formed using a plurality of flakes formed of the same material and having the same overall shape and size, but lacking said peripheral features.

34. 34. The method of claim 33, wherein the average tensile strength of the article formed with the plurality of modified polymer composite flakes is at least about 40% to about 60% greater.

35. the at least one edge feature has at least two angled sides; said at least two angled sides of each peripheral feature on at least one of said modified polymer composite flakes are contiguous; a vertex of an angle is formed at a contact point between the at least two angled sides together; a plurality of said edge features on said at least one modified polymer composite flake; 10. The method of claim 1, wherein at least two of said angled features of said plurality of peripheral features are also contiguous such that a portion of said peripheral edge of said at least one modified polymer composite flake has a zigzag pattern.

36. 36. The method of claim 35, wherein there are from about 2 to about 12 of said peripheral features in said zigzag pattern on said at least one modified polymer composite flake.

37. 37. The method of claim 36, wherein there are about 4 to about 8 of said peripheral features in said zigzag pattern.

38. 37. The method of claim 36, wherein said at least one modified polymer composite flake comprises at least three outer edges, at least two of which have said zigzag pattern.

39. 39. The method of claim 38, wherein there are about 4 to about 8 of said peripheral features in said zigzag pattern.

40. 13. An article formed by heat forming or curing a plurality of said modified polymer composite flakes formed by the method of claim 1.

41. 41. The article of claim 40, wherein the article is a component, device or part for use in a high temperature and / or pressure end use, or in an aircraft, medical device, robotics, automotive, semiconductor, or sports end use.

42. 42. The article of claim 41, wherein the article is a bracket, cover, fairing, or cabin sidewall attachment for use on an aircraft.

43. 41. The article of claim 40, wherein the article is a containment shell.

44. 41. The article of claim 40, wherein the article is formed by molding or curing the plurality of modified polymer composite flakes together with unmodified polymer composite flakes that may be the same or different from the at least one modified polymer composite flake formed by the method of claim 1.

45. 45. The article of claim 44, wherein said unmodified polymer composite flake incorporates the same polymer matrix material and the same long reinforcing fibers as said at least one modified polymer composite flake formed by the method of claim 1.

46. 1. A method of increasing one or more of average tensile strength and impact resistance of an article formed from composite flakes having at least one polymer matrix material and long reinforcing fibers extending through said polymer matrix material, said composite flakes having an outer surface having at least one outer edge, comprising: providing a plurality of modified polymer composite flakes, each of the modified polymer composite flakes having an outer edge feature along a portion of an outer edge of the flake; and forming said article using a plurality of said modified polymer composite flakes.

47. 47. The method of claim 46, wherein the impact resistance of an article formed with the modified polymer composite flake is high velocity impact resistance.

48. 1. An improved polymer composite flake for making an article, comprising: an exterior surface having an outer edge, the outer edge defining an outer surface area on the exterior surface, the modified polymer composite flake having a thickness along the edge extending in a direction generally perpendicular to the outer surface area defined by the edge; a polymer matrix material; long reinforcing fibers within the polymer matrix material; at least one perimeter feature on a portion of said perimeter of said modified polymer composite flake; The improved polymer composite flakes have the following properties:

49. 49. The improved polymer composite flake of claim 48, wherein the shape of said peripheral features is selected from triangular, parabolic, parallelogram, bell, bullet, arrowhead, and trapezoidal shapes.

50. 50. The improved polymer composite flake of claim 49, wherein there are two or more peripheral features, each peripheral feature being the same.

51. 51. The improved polymer composite flake of claim 50, wherein there are two or more peripheral features that together form a pattern.

52. 49. The improved polymer composite flake of claim 48, wherein said long reinforcing fibers extend unidirectionally within said polymer matrix material.

53. 49. The improved polymer composite flake of claim 48, wherein said improved polymer composite flake is formed from a polymer composite having long, continuous reinforcing fibers extending in one direction.

54. 49. The improved polymer composite flake of claim 48, wherein said peripheral feature has at least two angled sides angled toward one another at an angle of from about 5 degrees to about 120 degrees.

55. 55. The improved polymer composite flake of claim 54, wherein said at least two angled sides of said edge feature are angled toward one another at an angle of from about 20 degrees to about 90 degrees.

56. 56. The improved polymer composite flake of claim 55, wherein said at least two angled sides of said edge feature are angled toward one another at an angle of from about 20 degrees to about 60 degrees.

57. 57. The improved polymer composite flake of claim 56, wherein said at least two angled sides of said edge feature are angled toward one another at an angle of about 30 degrees to about 60 degrees.

58. 55. The modified polymer composite flake of claim 54, wherein said two angled sides are contiguous and together form an apex of said angle at a point of contact between said at least two angled sides.

59. 60. The improved polymer composite flake of claim 58, wherein there are a plurality of peripheral features, each having said at least two angled sides.

60. 60. The improved polymer composite flake of claim 59, wherein said at least two of said plurality of peripheral features are also contiguous such that at least a portion of said peripheral edge of each of said plurality of improved polymer composite flakes having said peripheral features has a zigzag pattern.

61. 61. The modified polymer composite flake of claim 60, wherein each of said modified polymer composite flakes has at least three outer edges, at least two of which have said zigzag pattern.

62. the long reinforcing fibers of each of the modified polymer composite flakes are unidirectional fibers that extend in a first direction through the modified polymer composite flake; the at least a portion of the outer edge of each of the flakes having the zigzag pattern extends in a second direction; 62. The improved polymer composite flake of claim 61, wherein said second direction is at an angle to said first direction.

63. 63. The improved polymer composite flake of claim 62, wherein said second direction is perpendicular to said first direction.

64. 64. The improved polymer composite flake of claim 63, wherein said second direction is at an angle of about 60 degrees to about 90 degrees relative to said first direction.

65. 49. The improved polymer composite flake of claim 48, wherein said polymer matrix material is a thermoplastic resin and is one or more of polysulfones, polysulfides, polyimides, polyamideimides, polyamides, polyarylene polymers, fluoropolymers, and combinations and copolymers thereof.

66. 66. The improved polymer composite flake of claim 65, wherein said polymer matrix material is a polyarylene polymer that is one or more of polyetherketone, polyetheretherketone, polyetherketoneketone, and combinations and copolymers thereof.

67. 49. The improved polymer composite flake of claim 48, wherein said long reinforcing fibers in said composite are one or more of inorganic fibers, ceramic fibers, glass fibers, graphite fibers, carbon fibers, thermoplastic fibers, thermoset fibers, and combinations thereof.

68. a plurality of peripheral features on said modified polymer composite flake; each of the edge features has at least two angled sides, the at least two angled sides being contiguous and together forming an angle apex at a contact point between the at least two angled sides; 49. The improved polymer composite flake of claim 48, wherein at least two of said plurality of peripheral features are also contiguous such that said at least one edge of said peripheral edge with said peripheral feature on each of said flakes has a zigzag pattern.

69. 70. The improved polymer composite flake of claim 68, wherein said zigzag pattern has from about 2 to about 12 peripheral features.

70. 70. The improved polymer composite flake of claim 69, wherein said zigzag pattern has from about 4 to about 8 peripheral features.

71. 69. The modified polymer composite flake of claim 68, wherein said modified polymer composite flake has at least three outer edges, at least two of which have said zigzag pattern.

72. 72. The improved polymer composite flake of claim 71, wherein said zigzag pattern has from about 4 to about 8 peripheral features.

73. 1. An apparatus for forming improved polymer composite flakes for use in forming articles, comprising: a feeder for controllably feeding a portion of a polymer composite, the portion of the polymer composite configured and sized to form a flake, the composite including at least one polymer matrix material and long reinforcing fibers extending through the polymer matrix material in the polymer composite; and a movable, controllable cutting device, the cutting device comprising one or more removable cutting templates configured to operate as a guillotine to cut a portion of the polymer composite fed by the feeding device into flakes and to provide at least one peripheral feature on a portion of an edge of the flakes cut from the cutting device; An apparatus comprising:

74. 74. The apparatus of claim 73, further comprising a controller for controllably operating one or more of the feeding device and the cutting device.

75. 74. The apparatus of claim 73, wherein different cutting templates can be used to impart different edge features to different edges of the cut flakes.

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