Modified long fiber reinforced polymer composite sheet with progressive end and method for providing same

Abstract

A method of providing a modified polymer composite sheet for forming an article, an article formed therefrom, and a modified polymer composite sheet are described wherein an article formed from such a modified polymer composite sheet has enhanced tensile strength and impact resistance, particularly at high speeds, such as at high temperatures. Also described is a method of improving the average tensile strength and / or impact resistance of an article formed from a polymer composite by using the modified polymer composite flakes herein. The method includes providing a composite material having at least one polymeric matrix material and long reinforcing fibers extending through a first fibrous material of the polymeric matrix material; and at least one sheet formed from the composite material, where the at least one sheet includes an outer surface having an outer edge, a portion of the outer edge configured to provide at least one outer edge feature to the outer edge of the at least one sheet, thereby providing a modified polymeric composite sheet.

Description

Invention Name

[0002] Modified long fiber reinforced polymer composite sheet with progressive ends, method for providing the same, and articles made therefrom with enhanced strength and impact resistance CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] Pursuant to 35 U.S.C. § 119(e), this nonprovisional patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 315,022, filed February 28, 2022, entitled “MODIFIED LONG FIBER REINFORCED POLYMER COMPOSITE SHEETS WITH TAPERED TERMINALS, METHODS FOR PROVIDING THE SAME, AND ARTICLE MADE THEREFROM WITH ENHANCEDED STRENGTH AND IMPACT RESISTANCE,” the entire contents of which are incorporated herein by reference. Background of the Invention Field of the Invention

[0006] The present invention relates to the field of discontinuous long fiber polymer composite products made from discontinuous long reinforcing fiber raw materials in sheet form, which can be made from continuous long fiber composite (such as tape) prepregs. More specifically, the present invention relates to the manufacture of such products, wherein the tensile strength, impact resistance (especially impact resistance under high-speed impact) and fatigue limit of the products are improved by providing improved discontinuous long reinforcing fiber polymer-based composite sheets (which have modified edge features that can form progressive ends).

[0007] Description of related fields

[0008] Products made of discontinuous long fiber composite materials are well known in the art and are usually made by various types of thermoforming processes. These products can be made of continuous long fiber composite materials, such as rods, particles, composite blocks and composite tapes, which can be prefabricated composites that can be chopped and remolded to prepare raw material shapes, such as plates, thin sheets or various particles, for forming final product products. These raw materials can be cut into short fibers or long fibers. A known composite material raw material, i.e., a reinforced thin sheet, is formed by cutting, chopping or using a waste portion of a unidirectional tape or similar long fiber reinforced continuous composite material. This composite tape can contain a relatively high fiber load, so the thin sheet formed by this tape can provide a high fiber load raw material. The thin sheet can be cut into discontinuous long reinforcing fiber thin sheets. Once formed, the product formed by this thin sheet may include randomly distributed discontinuous long fibers, and if necessary, may also include short fibers and / or part of the continuous long fibers.

[0009] Various forming methods are known and can be modified to obtain different results from these raw materials, including those used to change the properties of the matrix polymer and / or to change the degree of random fiber orientation in the matrix polymer.

[0010] As described above, the use of such unidirectional tapes to form sheets as a raw material for forming final product articles has the advantages of obtaining higher fiber loadings, good "wetting" of the fibers by the matrix polymer, uniform fiber distribution, less waste during processing, and the ability to produce complex molded geometries approaching injection molding. However, one disadvantage of discontinuous long fiber sheet materials formed from such unidirectional tapes is that such sheet materials generally tend to produce articles that have good properties and generally random distribution, but whose tensile strength may be lower than the desired strength. Typical values ​​for discontinuous long fiber articles using carbon fibers as reinforcing fibers, for example in a polyarylene (such as a polyetheretherketone matrix) are about 200 to 220 MPa. There is a need in the art to attempt to improve the strength of composite materials formed from chopped raw materials, and particularly the strength of composite materials formed from discontinuous long fiber composite sheets.

[0011] European patent application number EP 3 421 207 A1 provides a prior art method that attempts to form a composite product with a discontinuous fiber reinforced material. In this patent, the discontinuous reinforcing fiber bundles contain a cut surface that is inclined at a predetermined angle to the orientation direction of the individual yarns, so the lengths of the fiber bundles are different. The tip angle of the longer fiber bundle at the end of the discontinuous fiber bundle is smaller. This composite material can be used to manufacture shaped products of discontinuous fiber reinforced composite materials, which require high fluidity, two-dimensional isotropy and less mechanical property changes.

[0012] US Patent Application No. 6,251,809 describes a composite material of discontinuous fibers in which the fibers are treated to adhere to a polymer matrix in the warp and weft of a fabric pattern. A series of patterned cuts are made in the warp fibers.

[0013] U.S. Patent Application No. 8,709,319 describes sheets for forming thermoplastic articles, these sheets have fibers of different lengths. These sheets can be formed from a roll of unidirectional tape cut into different shapes and use fibers of different lengths.

[0014] U.S. Patent Application No. 9,283,706 describes forming with sheets that can be formed from thermoplastic fibers and discontinuous fibers. The sheets can be generally rectangular or other shapes, including elliptical, to provide fibers of different lengths, to make them more isotropic, and to provide strength.

[0015] U.S. Patent Application No. 10,160,146 teaches a method of molding using a feedstock of chopped or cut long fiber prepreg, which may include non-continuous long fibers and is in the form of a fiber-reinforced fabric, tape or rod. This material is fed into a first molding section in a single mold, wherein the first molding material has non-continuous long fiber reinforcement. The material is pushed into a port and molded in the molding section within the mold to provide more uniform molded parts that are stronger due to the enhanced fiber orientation.

[0016] U.S. Patent Application No. 8,529,809 describes the formation of composite panels, the layers of which are arranged in different directions to form the composite panel, which is described as a quasi-isotropic panel. The composite material is cut and divided using a cutting tool to form quasi-isotropic sheets from the panel. Tools such as lasers, saws, punches, or other structures can be used to produce squares, ovals, circles, rectangles, and triangles.

[0017] US Patent Application No. 5,151,322 describes composite panels formed from randomly arranged strips of unidirectional reinforcing fibers cut from a tape to increase strength in a quasi-isotropic manner.

[0018] U.S. Patent Application No. 9,302,434 includes a movable cylindrical mold for feeding sheets, which are described as being formed of thermoplastics with carbon fiber, glass fiber or other materials, which can be made by chopping unidirectional thermoplastic prepreg into the desired size and shape. Although rectangular shapes are shown, the patent mentions that the sheets can be other shapes.

[0019] US Patent Publication No. 2013 / 0189478A1 discloses the use of narrow flakes having an aspect ratio of at least 6:1 to form a composite material with consistent strength.

[0020] US Patent Application No. 9,724,854 describes the use of thermosetting resins to make composite materials from slices formed from unidirectional tapes. The slices are rectangular in shape, but may be other shapes, depending on how the unidirectional tapes are cut.

[0021] Thus, while sheets or slices of various sizes and shapes have been used to form various articles, and while attempts have been made to increase the strength of the formed articles and / or provide more uniform properties throughout the articles, there remains a need in the art to significantly increase the overall strength and uniformity of properties throughout an article formed from a polymer composite sheet, to increase impact resistance, particularly at high speeds, and to increase the failure limit of an article formed from a polymer composite sheet. It would also be desirable to be able to achieve the above objectives while being able to use an economical, low waste process using the composite sheet as a forming material and to provide an easy to use sheet forming apparatus. SUMMARY OF THE INVENTION

[0023] The present invention includes a method for forming a modified polymer composite sheet for forming an article, an article formed from the obtained modified polymer composite sheet, a modified polymer composite sheet for forming an article, and an apparatus for forming the modified polymer composite sheet.

[0024] In one embodiment of the present invention, the present invention includes a method for providing a modified polymer composite sheet for forming an article, the method comprising: (a) providing a composite material having at least one polymer matrix material and long reinforcing fibers of a first fiber material extending through the polymer matrix material; (b) forming at least one sheet from the composite material, wherein the at least one sheet includes an outer surface having an outer edge, a portion of the outer edge being configured to provide at least one outer edge feature to the outer edge of the at least one sheet, thereby providing a modified polymer composite sheet.

[0025] The method may further include forming at least one modified polymer composite sheet by cutting the composite material. At least one sheet may be cut by a cutting device. The shape of the composite material may be selected from a strip, a plate and a sheet. The long reinforcing fibers in the composite material may be unidirectional. The long reinforcing fibers in the composite material may be continuous long reinforcing fibers. In another embodiment, the composite material may be in a strip shape, and the long reinforcing fibers may be unidirectional continuous long reinforcing fibers. The long reinforcing fibers in the composite material may be continuous long reinforcing fibers.

[0026] In a further embodiment of the method, at least one outer edge feature may have at least two angled sides. The at least two angled sides of the outer edge feature may be angled to each other 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 an embodiment of this method, the at least two angled sides of the outer edge feature may also be adjacent and together form a vertex of an angle at a contact point between the at least two angled sides.

[0027] In the method, there can be a plurality of outer edge features in one or another embodiment. In such an embodiment having a plurality of outer edge features, at least two angled sides of each outer edge feature can be adjacent and together form an apex of an angle at a point of contact between the at least two angled sides, and at least two of the plurality of outer edge features can also be adjacent, such that the outer edge portion having at least one outer edge feature comprises a zigzag pattern. In another embodiment of the method, the outer edge of at least one modified polymeric composite sheet can comprise at least three outer edge portions, at least two of which can comprise a zigzag pattern.

[0028] In this embodiment, the long reinforcing fibers in at least one modified polymer composite sheet can be unidirectional and extend through at least one polymer composite sheet in a first direction, and the outer edge portion comprising the zigzag pattern can extend in a second direction at an angle to the first direction. The angle between the second direction and the first direction can be about 90°, or about 60° to about 90°.

[0029] In the embodiment of the above method, the shape of at least one outer edge feature can be selected from triangle (such as above-mentioned zigzag pattern), also can be parabola, parallelogram, bell, bullet, arrow-shaped and / or trapezoid.When a plurality of outer edge features are arranged, each outer edge feature can be identical or different.In addition, when there are two or more outer edge features, these edge features can form a pattern together.In another preferred embodiment, at least one outer edge portion can also be a parallelogram, for example rectangle, to form the rectangular tooth-like structure of pattern form.

[0030] In the present method, at least one modified polymer composite sheet may have four outer edge portions, two of which are opposite outer edge portions, and each opposite outer edge portion has a pattern formed thereon, so that the pattern basically extends along the two opposite outer edge portions, and so that the distance measured longitudinally through at least one modified polymer composite sheet between the two opposite edges remains basically consistent throughout the entire pattern.

[0031] In the above method, the polymer matrix material can be a thermoplastic and is one or more of polysulfone, polysulfide, polyimide, polyaramid, polyamideimide, polyamide, polyarylene polymer, fluoropolymer and combinations and copolymers thereof. The polymer matrix material can also be a polyarylene polymer, which is one or more of polyetherketone, polyetheretherketone, polyetherketoneketone and combinations and copolymers thereof. The polymer matrix material can be a fluoropolymer, which is a copolymer of tetrafluoroethylene and at least one perfluoroalkyl vinyl ether; a copolymer of tetrafluoroethylene and at least one other perfluoroolefin, polytrifluorochloroethylene, ethyltrifluorochloroethylene, ethyltrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride and combinations and copolymers thereof.

[0032] The long reinforcing fibers in at least one modified polymer composite sheet used in the method may be one or more of inorganic fibers, ceramic fibers, glass fibers, graphite fibers, carbon fibers, organic fibers (which may be thermoplastic fibers or thermosetting fibers) and combinations thereof.

[0033] In one embodiment, the outer edge of at least one modified polymer composite sheet in the above method defines a surface area having an overall shape on the outer surface of at least one sheet, and the overall shape of the surface area is generally a triangle, a polygon with at least five sides, a circle, a parallelogram or a trapezoid, and an outer edge feature can be formed on at least one edge portion of the surface area shape. The surface area defined by the outer edge can be a parallelogram selected from a square, a rectangle and a rhombus.

[0034] In another embodiment, there can be a plurality of modified polymer composite sheets, each sheet having a surface area defined by the outer edge of the sheet on the outer surface of the sheet, and a thickness measured along the outer edge of each sheet on a plane orthogonal to the sheet surface area, wherein the average external surface area of ​​the plurality of sheets is from about 20 square millimeters to about 650 square millimeters, and the average thickness of the plurality of sheets is from about 0.05 mm to about 0.25 mm. In another embodiment of the method, the average external surface area of ​​the plurality of modified polymer composite sheets is from about 20 square millimeters to about 325 square millimeters. In another embodiment, the average external surface area of ​​the plurality of sheets is from about 150 square millimeters to about 170 square millimeters, and the average thickness of the plurality of sheets is from about 0.1 to about 0.20 mm.

[0035] In the above method, when a plurality of modified polymer composite sheets having outer edge features are used to form an article, the average tensile strength of the formed article can be at least about 30% higher, or at least about 40% to about 60% higher, than the tensile strength of an article formed using a plurality of sheets formed from the same material, having the same overall shape and size, but lacking outer edge features.

[0036] At least one edge feature in the method may have at least two angled edges, wherein at least two angled edges of each outer edge feature on at least one modified polymer composite sheet are adjacent and together form a vertex of an angle at the contact point of at least two angled edges, and at least one modified polymer composite sheet may also have multiple outer edge features, and at least two of the multiple outer edge features may also be adjacent, so that a portion of the outer edge of at least one modified polymer composite sheet includes a zigzag pattern.

[0037] On at least one modified polymer composite sheet, there can be about two to about twelve, preferably about four to about eight outer edge features in a zigzag pattern. In addition, at least one modified polymer composite sheet can include at least three outer edge portions, at least two of which have a zigzag pattern. In such an embodiment, there can be about four to about eight outer edge features in the zigzag pattern.

[0038] In another embodiment, the present invention also includes an article formed by thermoforming or curing (depending on the matrix polymer) of a plurality of modified polymer composite sheets formed by the above method. Such articles can be components, devices or parts for high temperature and / or high pressure terminal applications or for aircraft, medical equipment, robots, automobiles, semiconductors or sports terminal applications. The article can also be a bracket, cover, fairing or cabin side wall attachment for an aircraft. The article can also be a containment shell.

[0039] The article can be formed by thermoforming or curing a plurality of modified polymer composite sheets together with unmodified polymer composite sheets, the unmodified polymer composite sheets can be the same or different from at least one modified polymer composite sheet formed by the method herein. In this case, the unmodified polymer composite sheet can contain the same polymer matrix material and the same long reinforcing fibers as at least one modified polymer composite sheet formed by the method herein.

[0040] In another embodiment, the present invention also includes a method of improving one or more of the average tensile strength, high speed impact resistance and fatigue resistance of an article formed from a composite sheet having at least one polymer matrix material and long reinforcing fibers extending through the polymer matrix material, wherein the composite sheet includes an outer surface having at least one outer edge. The method may include providing a plurality of modified polymer composite sheets, wherein each modified polymer composite sheet has an outer edge feature along a portion of the outer edge of the sheet, and forming the article using the plurality of modified polymer composite sheets.

[0041] Another embodiment of the present invention includes a modified polymer composite sheet for preparing an article, which includes: an outer surface having an outer edge, wherein the outer edge defines an outer surface area on the outer surface, and the modified polymer composite sheet has a thickness along the edge, and its extension direction is approximately orthogonal to the outer surface area defined by the edge; a polymer matrix material; long reinforcing fibers in the polymer matrix material; and at least one outer edge feature on the outer edge portion of the sheet.

[0042] The shape of the outer edge feature of the modified polymer composite sheet can be selected from a triangle, a parabola, a parallelogram, a bell, a bullet, an arrow and a trapezoid. The modified polymer composite sheet can also have more than one outer edge feature, and each outer edge feature can be the same. There can also be two or more outer edge features that form a pattern together.

[0043] The long reinforcing fibers in the modified polymer composite sheet may be unidirectional in the polymer matrix material. The modified polymer composite sheet may be formed from a composite material having unidirectional continuous long reinforcing fibers.

[0044] The outer edge feature can have at least two sides angled toward each other 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 an embodiment, the at least two angled sides of the outer edge feature can be adjacent and together form a vertex of an angle at the contact point between the at least two angled sides.

[0045] In another embodiment, there can be a plurality of outer edge features, each of which has at least two angled sides. At least two of the plurality of outer edge features can also be adjacent and form a vertex of an angle at the contact point between the at least two angled sides. At least two of the plurality of outer edge features can also be adjacent, so that at least a portion of the outer edge of each of the plurality of thin sheets having the outer edge feature can include a zigzag pattern. Each modified polymer composite thin sheet can include at least three outer edge portions, at least two of which have a zigzag pattern.

[0046] The long reinforcing fibers in each modified polymer composite sheet may be unidirectional fibers and extend through the modified sheet in a first direction, and at least a portion of the outer edge of each sheet containing the zigzag pattern may extend in a second direction, and the second direction may be at an angle to the first direction. In this case, the second direction may be orthogonal to the first direction, or the second direction may be at an angle of about 60° to about 90° to the first direction.

[0047] In another embodiment of the modified polymer composite sheet described herein, the polymer matrix material can be a thermoplastic, which can be one or more of polysulfone, polysulfide, polyimide, polyamide-imide, polyamide, polyarylene polymer, fluoropolymer and combinations and copolymers thereof. The polymer matrix material can 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 material can be one or more of inorganic fibers, ceramic fibers, glass fibers, graphite fibers, carbon fibers, organic fibers (including thermoplastic fibers and thermosetting fibers) and combinations thereof.

[0048] In another embodiment of modified polymer composite thin slice described herein, a plurality of outer edge features can be arranged on the modified thin slice, each outer edge feature can comprise at least two angled edges, at least two angled edges can be adjacent, and form an angled vertex together at the contact point between at least two angled edges, in addition, at least two outer edge features in a plurality of outer edge features can also be adjacent, like this, at least one edge portion of the outer edge with outer edge feature on each modified polymer composite thin slice just comprises zigzag pattern. Approximately two to approximately twelve outer edge features can be arranged in the zigzag pattern, preferably approximately four to approximately eight outer edge features are arranged. The modified polymer composite thin slice can comprise at least three outer edge portions, wherein at least two have zigzag pattern. In such embodiment, approximately four to eight outer edge features can be arranged in the zigzag pattern.

[0049] In another embodiment of the present invention, there is provided an apparatus for forming a modified polymer composite sheet for forming an article, the apparatus comprising: a feeder for controllably feeding a portion of a composite material, the configuration and size of the portion of the composite material being used to form a sheet, the composite material comprising at least one polymer matrix material and long reinforcing fibers extending through the polymer matrix material in the composite material; and a movable and controllable cutting device, the cutting device operating as a cutting table, cutting the portion of the composite material fed by the feeder into sheets, and comprising one or more removable cutting templates configured to provide at least one outer edge feature on an edge portion of the sheet cut from the cutting device. In one embodiment, the apparatus further comprises a controller for controllably operating the feeder and / or the cutting device. Different cutting templates can be used to provide different edge features for different edge portions of the cut sheet. Brief description of several views of the drawing

[0051] The present invention may be better understood by reading the above summary and the following detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. For the purpose of illustrating the present invention, the accompanying drawings show presently preferred embodiments. However, it should be understood that the present invention is not limited to the precise arrangements and instrumentalities shown in the drawings. In the accompanying drawings:

[0052] Figure 1 is a top plan view representation of a prior art composite sheet of the type that can be used in embodiments of the methods herein and used to make the control samples in Examples 1, 2, and 3 herein;

[0053] Figure 1A yes Figure 1 Side view of the composite sheet in the middle;

[0054] Figure 2 is a perspective representation of another sheet that may be used in one embodiment of the method;

[0055] Figure 3 is a top plan representation of a modified sheet having outer edge features according to an embodiment of the present invention, the sheet being made according to an embodiment of the present method, the sheet being used to make the present invention samples A, B and C in Example 1 of the present invention;

[0056] Figure 3A is a top plan view of an embodiment of the modified sheet sample 30-4 used in Example 2 herein;

[0057] Figure 3B is a top plan view of an embodiment of the modified sheet sample 60-4 used in Example 2 herein;

[0058] Figure 3C is a top plan view of an embodiment of modified sheet sample 90-4 used in Example 2 herein;

[0059] Figure 4 yes Figure 3 A perspective representation of the modified sheet in ;

[0060] Figure 5A is a plan view of an embodiment of the modified sheet sample 30-8 used in Example 2;

[0061] Figure 5B is a plan view of an embodiment of the modified sheet sample 60-8 used in Example 2;

[0062] Figure 5C is a plan view of an embodiment of the modified sheet sample 90-8 used in Example 2;

[0063] Fig. 6A is a plan view of an embodiment of the modified sheet sample 30-12 used in Example 2;

[0064] Figure 6B is a plan view of an embodiment of the modified sheet sample 60-12 used in Example 2;

[0065] Figure 6C is a plan view of an embodiment of the modified sheet sample 90-12 used in Example 2;

[0066] Fig.6D is a plan view of an embodiment of modified sheet sample 5-12 used in Example 2;

[0067] Fig. 6E is a plan view of an embodiment of the modified sheet sample 15-12 used in Example 2;

[0068] Fig. 7Ais a plan view of an embodiment of the modified sheet sample 6X 2 used in Example 2;

[0069] Figure 7B is a plan view of an embodiment of the modified sheet sample 6X 1 used in Example 2;

[0070] Fig. 8A is a plan view of an embodiment of a modified sheet used as control sample D in Example 2;

[0071] Figure 8B is a plan view of an embodiment of a modified sheet used as a control sample E in Example 2;

[0072] Fig. 9 is a graphical representation of the average tensile strength (MPa) of articles formed from modified sheets of the inventive sample of Example 2 and the control sample;

[0073] Fig.10 is a graph of the average tensile strength (MPa) of articles formed from the modified sheets of the inventive and control samples of Example 2 as a function of the depth (mm) of any outer edge features present, wherein the depth represents the length cut into the original composite sheet for the outer edge features;

[0074] Fig.11 Graph showing the tensile strength (MPa) of articles formed from unmodified commercial polymer sheets and modified versions of the same commercial sheets in Example 1

[0075] Fig.12 is a photograph of a fixture used to mount a composite plate test sample in a high-speed impact test of Example 3;

[0076] Fig.13 is a schematic diagram of the impact velocity of hailstones on the composite panel tested in Example 3, for Figure 3 and Figure 4 Various test samples with modified sheet designs, and control samples formed in the manner of control sample D of Example 2;

[0077] Fig.14 is a plan view of a modified sheet structure according to an embodiment of the present invention, the edge portion of the sheet having a triangular pattern of outer edge features, wherein adjacent outer edge features are connected by a single contact point, the edge features having angled sides that intersect at vertices;

[0078] Fig.15 is a plan view of a modified sheet structure according to an embodiment of the present invention, the edge portion of the sheet having a parabolic outer edge feature pattern, wherein adjacent outer edge features are connected by a single contact point, and the edge features have curved sides and meet at terminal curves;

[0079] Fig.16 is a plan view of a modified sheet structure according to an embodiment of the present invention, the sheet having an edge portion having a parallelogram-shaped pattern of outer edge features, wherein the edge features are connected by substantially linear edge portions, the sides being angled sides that are parallel to each other but connected at the ends by connected linear ends;

[0080] Fig.17 is a plan view of a modified sheet structure according to an embodiment of the present invention, the edge portion of the sheet having an arcuate pattern, wherein adjacent outer edge features are connected by arcuate edge portions, the edge features having partially linear sides that are parallel to each other but are bent toward each other at the ends of the edge features to form semicircular ends, so that the outer edge features resemble the ends of a tongue depressor or bell, wherein portions of the bell-shaped sides are linear and parallel;

[0081] Fig.18 is a plan view of a modified sheet structure according to an embodiment of the present invention, wherein edge features in the form of triangles are provided at an edge portion of the sheet, extending outwardly on one edge portion of the sheet having an apex and extending along the length of the edge portion, and two half triangles extending outwardly on an opposing edge portion of the sheet (to define an inwardly extending triangle), thereby maintaining a substantially uniform fiber length along the sheet;

[0082] Fig.19 is a plan view of a modified sheet structure according to an embodiment of the present invention, wherein opposite edge portions of the sheet have a pattern of outer edge features of two different types, one being rectangular outer edge features (having parallel sides and terminating in linear ends) and the other being bullet-shaped outer edge features (having curved sides and converging in sharply curved ends), the features extending in an alternating manner along a first outer edge of the sheet and also extending in an opposite pattern to another opposite outer edge of the sheet, such that the fiber length remains substantially constant along the sheet, and the alternating outer edge features on each side are connected by substantially linear edge portions;

[0083] Fig. 20 is a plan view of a modified sheet structure according to an embodiment of the present invention, wherein edge features are provided at edge portions of the sheet in the form of a single full curved feature extending outwardly in a convex manner on one edge portion of the sheet and extending along the length of the edge portion, and an outwardly extending concave curved feature (to define an inwardly extending curved feature) on an opposing edge portion of the sheet, thereby maintaining a substantially uniform fiber length along the sheet;

[0084] Fig.21is a plan view of a modified sheet structure according to an embodiment of the present invention, wherein the sheet has a pattern formed on opposite edges of the sheet, wherein the outer edge features are "arrow" shaped outer edge features, the arrow shape being formed by a bottom rectangular portion and an end triangular portion, the two sides of the end triangular portion being connected at a vertex, and the rectangular portions of each outer edge feature being connected by a substantially linear edge portion. The pattern extends across a first outer edge portion of the sheet, and the reverse pattern extends across an opposite outer edge portion of the sheet;

[0085] Fig. 22 is a plan view of a modified sheet structure according to an embodiment of the present invention, wherein the sheet has a pattern formed by rectangular outer edge features having parallel linear sides connected at ends by linear end portions, wherein the outer edge features are connected by substantially linear edge portions;

[0086] Fig.23 is a plan view of a modified sheet structure according to an embodiment of the present invention, wherein opposing edge portions of the sheet have a pattern wherein outer edge features are shaped in a "dovetail" manner to resemble isosceles trapezoids having angled sides and having ends connecting the angled sides, the ends being linear ends, wherein the outer features are connected by substantially linear edge portions;

[0087] Fig.24 is a photograph of an apparatus for forming a modified sheet according to the present method;

[0088] Fig.24A yes Fig.24 Photographs of the two removable cutting templates used in the device;

[0089] Fig.25 is a graph of peak pressure (MPa) versus cycle number in fatigue test data of samples in Example 4, the samples being made from control sample X (a composite material formed from unmodified flakes according to Example 1) and inventive sample Y (a composite material formed from modified flakes according to Example 1); and

[0090] Fig.26 Schematic diagram of the type of damage caused by high-speed hail impact to the composite panel tested in Example 5, which is made of a composite material of the control sample X and the invention sample Y in Example 4 and the composite invention sample Z (formed by a modified sheet providing longer fibers in the length direction and having the same edge modification as the invention sample Y in the width direction of the modified sheet). Detailed description of the invention

[0092] In the description herein, unless otherwise specified, words such as “inside” and “outside”, “upward” and “downward”, “inwardly” and “outwardly”, “outside” and “inside”, “right” and “left”, “up” and “downward”, “distal” and “proximal” and words of similar meanings all refer to directions in the accompanying drawings to help illustrate the features of the present invention.

[0093] The present invention includes a method for providing a modified polymer composite sheet for forming an article, a modified polymer composite sheet and an article formed therefrom having higher tensile strength, higher impact strength (especially under high-speed impact conditions) and higher failure limit, and also includes an apparatus for preparing the modified polymer composite sheet.

[0094] The modified polymer composite sheet of this article can be cut, stamped, molded or otherwise formed from a composite material by various different types of sheets. In an embodiment of the present invention, the composite material is formed from a polymer matrix material, and the matrix material includes at least one long fiber formed from a first fiber material. Such sheets can also be purchased from the market, or formed independently, and then provided for use in the present method.

[0095] If thin slice is formed with composite material, composite material is preferably a preformed composite material, and long reinforcing fibers are extended in the composite material, which can be a single fiber, a tow, a braid or a bundle. Composite material can also be formed by the braided reinforcing fibers in the polymer matrix material, or use unidirectional long reinforcing fibers that can pass through the polymer matrix material. In a preferred embodiment, the fiber is unidirectional, preferably long reinforcing fibers. Long reinforcing fibers can be continuous or discontinuous. Similarly, these reinforcing fibers of the same type for making the composite material that can provide thin slice for the method herein are also preferably the same as the fibers in the thin slice provided by the method herein. In addition, the same polymer matrix material for forming composite material is preferably the same as the polymer matrix material in the thin slice provided by the method herein.

[0096] The long reinforcing fibers in the modified polymer composite material sheet of the present invention and the same first fiber material in this reinforcing material can be a single type of fiber material or a mixed material, that is, more than one fiber material can be used in combination as a reinforcing long fiber material for impregnation, addition to a polymer matrix material or other application of a polymer matrix material, so that the long reinforcing fibers are basically wetted to form a composite material, and finally the modified polymer composite material sheet provided by the present invention is formed from this composite material.

[0097] Suitable long reinforcing fiber materials ("first fiber materials") include, for example, but not limited to, various inorganic long reinforcing fibers, such as ceramic fibers, glass fibers, graphite fibers, carbon fibers, quartz fibers, alumina fibers, silicon carbide fibers, basalt fibers, boron fibers, and combinations thereof, such as glass / carbon, glass / graphite / carbon, graphite / carbon, and ceramic / glass. In addition, organic fibers such as thermoplastic and thermosetting reinforcing long fibers, including first fiber materials such as aramid fibers and polybenzoxazole fibers, can also be used, and they can be used alone or mixed with glass fibers, ceramic fibers or carbon fibers.

[0098] In a fiber blend or combined fiber reinforcement, other fibers may be provided to the fiber matrix in the form of shreds, filaments or whiskers prior to impregnation. In addition, such blends may also include bundles, tows and braids extending in the direction of the long fibers, and / or various woven or mixed fiber materials extending in multiple directions to provide strength and / or other desired properties.

[0099] Preferred long fiber materials include ceramic, glass, graphite, carbon and / or plastic (thermoplastic and thermoset) fibers (such as aramid fibers ( and ) or polybenzoxazole fiber (can have )).

[0100] The long reinforcing fibers can be unidirectional or bidirectional continuous fibers or discontinuous fibers (preferably bidirectional fibers have about 50% of the fibers in the parallel direction and about 50% of the fibers in the perpendicular direction), tensile breaking fibers, woven fibers, and woven continuous fibers. Preferred reinforcing fibers are unidirectional fibers. In addition, the reinforcing fibers can also be woven fibers or mixed fibers. Depending on the selected fibers, the preferred diameters of the long reinforcing fibers generally include about 0.1 microns, about 5 to about 15 microns, and about 7 to about 10 microns. The range of boron fibers is 100 microns to about 140 microns, and the range of glass fibers is about 5 microns to about 25 microns. The range of basalt fibers is about 10 microns to about 20 microns.

[0101] Preferably, relative to the total volume of the composite material, the long fiber reinforcement accounts for about 30% or more of the composite material volume for forming the modified polymer composite sheet provided herein, preferably 40% or more, more preferably 50% or more, for example, can account for about 60% to about 90%. It is preferred that the long fibers account for about 40% to about 80% of the composite material volume, and most preferably account for about 50% to about 70% of the composite material volume, and it is understood that fibers of different diameters can make the preferred volume higher or lower.

[0102] The long reinforcing fibers used in the composite material for providing the modified polymer material sheet in the present invention can be added to the composite material by any suitable technology known in the art or to be developed, such as prepregs or other impregnated composite material structures containing long fibers, provided that the structure produced is suitable for forming the polymer composite material for forming the article in the present invention. Within the scope of the present invention, the modified polymer sheet material in the present invention can also be formed by direct molding, such as molding or stamping the composite material containing the long reinforcing fibers into a modified sheet form.

[0103] In a preferred embodiment, a continuous long reinforcing fiber structure can be used, such as impregnated continuous fiber tape, plate, sheet, fabric or the like. As described herein, the continuous fiber in this type of structure is generally at least about 0.20 inches in length, at least about 0.5 inches (1.27cm) in the embodiments herein. The fiber of at least 0.5 inches in length is both easy to process and has good performance. As is well known, longer fibers generally have better mechanical properties, but processing is not always so easy. Therefore, it should be understood by those skilled in the art that fiber length can be selected to balance the mechanical properties and processing conditions of a particular process. This structure or other continuous fabric tapes, plates, sheets, rods or the like can be cut, chopped, stamped or otherwise formed into composite sheets of various sizes, but preferably retain part or most of the original long reinforcing fiber length, such sheets are preferably discontinuous long fiber sheets. The example of this type of structure preferably used to form the modified polymer composite sheet used in the method of the present invention is to have a length to diameter ratio greater than about 100 reinforcing long fibers those.

[0104] This continuous long reinforced fiber composite structure is then cut, chopped, stamped, die-cut or otherwise formed into a modified polymer composite sheet as described herein using a cutting device. In a preferred embodiment of the present invention, there is provided Fig.24 The device A shown is used to form a thin sheet for forming an article. In the device A, a feeder D controllably feeds a portion of a polymer composite material (as shown in the polymer composite unidirectional tape E in the figure) into a cutting device G. The portion of the composite material feed is configured and sized to form a thin sheet, so it can be set for a thin sheet of a specific size. If a thin sheet of one-half inch is to be used, it is modified according to the present invention, so that the feeder D can feed a 0.5-inch portion into the cutting device G. The composite material can have a polymer matrix material, and long reinforcing fibers extending through the polymer matrix in the composite material, and the composite material can be any embodiment described elsewhere herein. The feeder D can be controlled by a feed controller J driven by a motor set for a thin sheet of a specific size.

[0105] The cutting device G is preferably reciprocatingly movable so as to cut the entire composite strip. Depending on the design or orientation of the cutter, cutting can be done in either an up and down stroke or a left and right stroke. As shown, a guillotine blade GB is located in the center of the cutting device G to cut the composite strip E passing through the central cutting zone of the cutting device. The controllable cutting device can be set to operate at a certain interval speed so as to cut edge features into composite strip portions as the composite strip passes through the device. For example, as shown, when the guillotine blade (GB) is opened to separate the template (described below), the motor "J" drives a roller to move the composite strip forward a length corresponding to the required or set sheet length. The strip movement stops, at which time the guillotine blade GB is pushed downward to cut the strip and then the above process is repeated. Thus, G works as a cam shaft, synchronized with the movement of the motor J. When the composite strip is cut, for example, in a zigzag pattern, the guillotine blade (GB) is lifted upward and opened again for the next section of the strip to be moved forward by the operation of the motor J. Thus, by the movement of the motors J, the strips are moved forward in a synchronized manner so that the composite strip is formed into a sheet and the selected cutting pattern can be repeated for each cut in each desired sheet length.

[0106] like Fig.24A As shown, the cutting device G includes one or more removable cutting templates Q, which can be removably mounted in the cutting device by any suitable fasteners or pins. As shown, the template Q has fastener openings X for fixing the template in the device. The template can be made with different cutting teeth T so as to provide at least one outer edge feature for one or more portions of the edge of the modified sheet formed when the composite material strip is cut using the cutting device G.

[0107] As shown, the cutting template Q has teeth T, such as manufactured by machining or other tools, so that the teeth T shown can provide the desired edge features. Fig.24A In the example template Q shown, the template can provide triangular outer edge features on opposite edges of the sheet while cutting from a unidirectional tape, so that the modified polymer composite sheet can be cut and the features provided simultaneously in the same cutting device G. However, it should be understood by those skilled in the art that based on the present disclosure, various templates Q can be made to cut sheets with different outer edge features in the cutting device, and the templates can be exchanged in a modular manner to perform different cuts. In addition, it should be understood that any cutting method for forming a reinforced long fiber sheet from a composite material having long fibers (which can be continuous long fibers) is within the scope of the present invention, including the above-mentioned cutting processes, die cutting, manual forming or direct forming (such as by thermoforming of a prefabricated sheet).

[0108] The apparatus may also include a built-in or independently operable controller for controlling the settings and operation of the feeder and / or cutting device. Controls, such as digital controls, for the above-mentioned cutting device G can be used to control the operation of the motor J that advances the composite material strip, as well as the motor that drives the camshaft in the cutting device G, thereby also controlling the position of the guillotine blade (GB). Although the apparatus A shown in the figure is used to form the modified polymer composite sheet in this embodiment, it can also be formed on a larger industrial scale using a variety of feeders and cutting devices with interchangeable or fixed cutting templates.

[0109] The modified polymer composite sheet herein can be of various sizes and shapes, as discussed herein. In addition, composite materials used to make commercially available sheets can also be used in the method for providing modified polymer composite sheets herein. In the composite material used as a raw material, the long fibers can remain continuous long fibers in the resulting modified polymer composite sheet, or the modified polymer composite sheet used can be formed or cut from discontinuous long fibers. Commercially available sheets can also be combined with the modified polymer composite sheets formed herein to prepare articles, wherein different types of sheets are mixed together before being formed or otherwise thermoformed into articles.

[0110] Reference Figure 1 and Figure 1A The standard polymer composite sheet (i.e., the unmodified commercially available composite sheet) referred to herein, when used with the modified polymer composite sheet according to the present method, can be generally represented by reference to the example of a polymer composite sheet 10 having a length l extending along a longitudinal axis x-x' through the material sheet and a width w extending along a transverse axis y-y', and if circular, such as Figure 2 Another commercially available unmodified sheet 10' is shown in FIG. If the sheet is square, the length l and width w must be the same. Note that Figure 1 , Figure 1A and Figure 2 Similar features in the sheets in FIG. 1 are given corresponding reference numerals.

[0111] Each of the measurements of width and length (or diameter) is measured between respective opposing outer edge portions 12, 13 (defining the width) and 15, 17 (defining the length) on the circumference, also referred to herein as outer edges 14. The outer edges 14 define a surface area A at the outer surface 16 of each sheet. As with most manufactured sheets, the surface area A is preferably planar, although it can be irregular or non-planar if desired. In prior art embodiments, the surface area A has a first surface area 18 on one face of the sheet and a second opposing surface area 19 on the opposing face of the sheet, each surface area being generally of the same or similar size. Since the sheets are generally thin and nearly two-dimensional, the surface areas 18 and 19 are generally identical. The outer surface 16 extends around the entirety of the sheet and includes the first and second opposing surfaces 18, 19 and the edge portions 12, 13, 15 and 17 of the sheet, which define the shape of the opposing surfaces 18, 19 and provide the sheet with a thickness t extending along the z-z' axis between the two opposing surfaces 18, 19.

[0112] exist Figure 2 In the thin sheet, the diameter d is measured by a straight line extending from a first point P1 on the circumferential edge 14', passing through the center point CP' of the area A', and extending through the area A' to the point P2 farthest from the starting point on the edge 14'.

[0113] It should be understood that the generally planar areas A, A' on the sheet may be planar, substantially planar, or only partially planar, and may or may not include surface roughness or features extending from the opposing surface areas 18, 19 of the sheet. The length and width may be the same or different. Furthermore, the shape may be somewhat irregular.

[0114] The flakes also typically include a small but measurable thickness t, t' measured through the flake along the z-z' axis orthogonal to the length l and width w (or diameter d), from one opposing first surface region 18, 18' to the other opposing second surface region 19, 19'. Preferably, the thickness t is less than the length l and width w (t' is less than the diameter d). Preferred commercially formed prior art flakes that can be used with the modified flakes formed herein or have similar sizes and shapes have a shortest dimension (l, w or d) on the opposing first and second surface regions 18, 19 (18', 19') that is greater than the corresponding thickness t, t' of the corresponding flake.

[0115] While these parameters are illustrated using square and circular flakes as examples of prior art, it should be understood that other shapes and geometries may be applicable as is generally known, and that the thickness of commercially available flakes, including flakes that may be used with the modified flakes formed herein, may also vary.

[0116] The thickness of the sheet is important for tensile strength. A thickness of about 140 microns is the standard thickness of the most beneficial commercial sheet products. Commercially available thin composite tapes with a thickness of about 44 microns are available, but such tapes are much more expensive than standard composite tapes. In order to reduce production costs, composite tapes are produced with a thickness of about 250 microns or even as thick as 2000 microns.

[0117] When making sheets from this type of composite tape and similar composite materials, the narrowest (l or w) commercially available sheets are typically about 1 / 16 inch wide (about 1588 microns). Sheets as large as 1 inch in length and / or width are available, but not common. Such sheets 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 sheets may be about 1 inch or 2 inches in length or width.

[0118] In a preferred embodiment, the modified polymer composite sheet having outer edge features provided by the method of the present invention has a length and / or width of about 1 inch, or a length and width of about 0.5 inches, and most preferably has an overall square structure (aspect ratio of 1:1) (where these dimensions are measured from one edge portion to the edge portion through the sheet in the longitudinal or transverse direction). However, the present invention also contemplates the use of other aspect ratios of 1:16 and other shapes.

[0119] The modified polymer composite sheet provided by the method of the present invention for forming an article can be cut or otherwise formed into a variety of shapes, including generally triangular, circular, polygonal (preferably with five or more sides), trapezoidal or parallelogram (such as square, rectangular or rhombus). The term "generally" having a certain shape or having an "overall shape" means that when the sheet is viewed from a top or bottom plan view, its outer edge or periphery defines an area on the opposite faces 118, 119, which has an overall shape configuration that can be observed from the outer portion of the outer edge 114 of the modified polymer composite sheet or the outer portion of the circumferential outer edge 114' of a circular sheet. The shape may or may not be, for example, a perfect triangle, circle or parallelogram, etc., but the shape refers to the geometric name that most closely approximates the overall shape of the indicated area observed in two dimensions, without particular reference to the outer edge features formed in one or more portions of the outer edge as further described below. In most preferred embodiments, the overall shape of the modified polymer composite sheet is generally square, rectangular or rhombus.

[0120] Reference standard commercially available flakes 10 and Figure 1 The average surface area determined by measuring the relative areas 18, 19 on a plurality of sheets and averaging the plurality may be about 20 mm 2 To about 650mm 2, the average thickness is preferably about 0.05 mm to about 0.25 mm. Thin sheets of similar size can also be cut out of the composite material to form the modified polymer composite sheet herein. In a more preferred embodiment, the average surface area can be about 20 mm 2 To about 325mm 2 , or about 150mm 2 To about 170mm 2 , with an average thickness of about 0.1 mm to about 0.20 mm 2 Those skilled in the art will recognize from the present disclosure that these dimensions may vary according to different purposes and effects. In addition, these ranges also include other ranges within the parameters of this article.

[0121] The polymer composites from which the commercially available prior art flakes are derived, and the modified polymer composite flakes provided by the method herein, are composed of a fiber area weight content (e.g., 150 g / m 2 ) and resin content (e.g. 32% by weight of polymer such as PEEK). The density of the known fiber (e.g., the density of carbon fiber is 1.78 g / cm 3 ) and the density of the polymer (e.g. the density of PEEK is 1.30 g / cm 3 ), which indicates that the tape thickness in this case is 139 microns, calculated as: 150*(1 / 1.78+(0.32 / 0.68) / 1.3)=139. Other commercially available composite tape suppliers also provide tapes with thickness and resin content. The sheet thickness of commercially available sheets and the modified sheets provided herein will be the same as the thickness of the tape or other composite material cut into sheets.

[0122] Existing commercially available composite materials that can be used to form the modified polymer composite sheets described herein are available from Solvay in both thermoset and thermoplastic forms and include phenolic polymers, epoxy polymers, polyetherimide with reinforcing long fibers such as APC. TM PEKK or PEEK reinforced tape with unidirectional carbon fibers, Glass and carbon fiber reinforced sheet materials; available from Celanese Corporation (Celanes), such as CFR composite tapes containing unidirectional fibers and various thermoplastics including polyolefins, polyamides, and polyphenylene sulfide; obtained from Evonik, e.g. UD tape, etc.; obtained from Greene, Tweed & Co. Includes sheets formed from carbon fiber and thermoplastics (including PEEK); thermoplastic composite tapes such as polyolefins and polyamides containing glass and carbon fibers obtained from SABIC; and thermoplastic composite tapes obtained from Toray Industries, Inc. TC1200 and related products can be provided as unidirectional carbon fiber reinforced polymers (such as epoxy polymers and PEEK). These examples are not limiting. In a preferred embodiment, the carbon fiber / PEEK composite can be used in the form of a unidirectional tape, from which discontinuous long fiber modified sheets can be cut. Such tapes are available from companies such as Solvay, Toray Industries, Inc. Suprem SA, Barrday, Inc., Toho Tenax (Teijin Co., Ltd.) and Victrex plc.

[0123] Although commercially available composite materials can be used, prepregs, such as tapes with fiber reinforcement layers, can also be formed in situ at the same time and / or at the same location as cutting the modified polymer composite sheet according to the method of the present invention. They can be formed by cutting, stamping, die cutting or otherwise shaping the composite material into a modified polymer composite sheet having a polymer matrix material and long reinforcing fibers (such as the above-mentioned fibers).

[0124] The matrix polymer can be a thermoplastic or a thermosetting material. When used as a polymer matrix material for the composite material and sheet of the present invention, preferred thermoplastics include polymeric plastics and resins that can be loaded or filled with reinforcing materials and can flow under the action of heat. Exemplary thermoplastics include, but are not limited to: polyolefins (such as polyethylene, polybutylene, polypropylene, high-density polyethylene), poly(acrylonitrile-butadiene-styrene) (ABS), polystyrene, polybutadiene, polyacrylonitrile (PAN), poly(butadiene-styrene) (PBS), poly(styrene-acrylonitrile) (SAN), polybutylene, cellulosic resins (such as ethyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate and cellulose nitrate), polyvinyl alcohol (EVA), polyethylene vinyl acetate, fluoropolymers (such as melt-processable fluoroplastics, including copolymers of tetrafluoroethylene (TFE) and at least one perfluoroalkyl vinyl ether (PAVE) (PFA), copolymers of TFE and at least one other perfluoroolefin (such as hexafluoropropylene) (FEP), poly(chlorotrifluoroethylene) (PTFE), polyethyl trifluoroethylene ... Fluorochloroethylene (ECTFE), polyethyltrifluoroethylene (ETFE), polyvinyl fluoride (PVF) and polyvinylidene fluoride (PVDF)), ionomers, liquid crystal polymers (LCP), polyacetals, polyacrylates, polyamides (such as nylon 12, nylon 6), polyphthalimide, polyimide, polyetheramide, polyamideimide, polyphenol, polycarbonate, polyester, thermoplastic polyurethane, polyvinyl chloride (PVC), polyvinylidene chloride, polyethylene, polyphenylene oxide (PPO), polyphenylene ether, polyphenylene ester, polyphenylene ether ester, polyphenylene sulfide, polysulfone, polymethylpentene, polyketone, polyaryletherketone, polyarylether and polyaryletherketone (such as polyetherketone (PEK), polyetherketoneketone (PEKK) and polyetheretherketone (PEEK)), polyethylene chloride products, polyarylamide and thermoplastic biscitraconicimide.

[0125] The matrix material may also include thermosetting materials, including certain elastomers (such as ethylene propylene diene monomer (EPDM), ethylene propylene rubber (EPR) and thermosetting polyurethane elastomers), epoxy resins, thermosetting 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, thermosetting polyvinyl esters, thermosetting polyurethanes, polytetrafluoroethylene, melamine, polyalkyd resins and xylene resins. These polymers may be used alone or in the form of various copolymers or combinations thereof, wherein the combination may include mixtures, alloys, blends and crosslinked combinations of one or more such polymers and / or one or more copolymers thereof.

[0126] Copolymers (polymers formed from two or more monomers in random or block form, or graft copolymers, any of which may have multiple monomer components or reactants) of each or any of these thermoplastics, whether known or yet to be developed, may also be used.

[0127] Furthermore, if such thermoplastics can still be used to form modified flakes or composites (or combinations of composites), the modified flakes can be formed by cutting the composite into modified flakes, which can be further derivatized and / or include functional groups (whether terminal and / or in the chain), branched and / or linear backbone structures, other unsaturated positions along the chain or side groups, etc. Functional groups that can be provided include aromatic groups, keto groups, acetylene groups, acid groups, hydroxyl groups, sulfur-containing groups, sulfates, sulfites, mercapto groups, phosphino groups, carboxyl groups, cyano groups, phosphites, halogens, oxygen / ethers or esters (which can also be incorporated in the chain or side chains), carboxylic acids, nitrates, ammonium, amides, amidines, benzamidines, imidazoles, etc.

[0128] While these polymers are preferred, they should not be considered an exhaustive list, and one skilled in the art will appreciate from this disclosure that other thermoplastics may be used in the present invention without departing from the scope of the present invention.

[0129] Preferred materials among the above materials include engineering plastics, such as polysulfone, polyimide, polyamide-imide, polyetherimide, polyamide, polyphenylene oxide and sulfide, and polyarylene materials, such as PEEK, PEK, PEKEKK and PEKK. The above fluorine-containing polymers can also be used as preferred materials, as long as they can form a composite material with reinforcing long fibers to make the modified sheet of this article, and have fluidity at the processing temperature, so as to form an article with the modified polymer composite sheet.

[0130] The modified polymer composite sheet can be formed from a composite material of the various polymers and long reinforcing fibers described above, but more than one composite material can also be provided so that, when forming an article, a mixed modified sheet or a modified sheet formed from different composite materials (or from mixed thermoplastics and / or reinforcing fiber materials) can be used together and / or mixed with existing commercially available sheets.

[0131] The composite material for providing the modified polymer composite sheet herein can be composed of only reinforcing long fibers and polymer matrix materials, or one or more additives are provided, including other fillers and / or reinforcing agents known in the art or to be developed. The various additives used can include other types of reinforcing fibers or fillers and additives, such as pigments, dyes, glass beads or glass balls, carbon nanotubes, ceramics, meshes, honeycombs, mica, clay, organic colorants, plasticizers, thixotropic agents, flame retardants, ultraviolet light absorbers, fillers, stabilizers, silicon dioxide, silicon dioxide, aluminum oxide, talcum powder, short glass fibers, barium sulfate, PTFE short fibers, TFE copolymer short fibers, reinforcing fibers of other different lengths of ribbon-like or sheet-like fibers, wollastonite, titanate whiskers, compatibilizers, rheological agents or thixotropic agents, antistatic agents (also can be added by adding functional groups and / or graft copolymers in thermoplastic matrix), chopped or short carbon fibers and other similar fillers, friction additives and reinforcing agents. Based on the total weight of the composite material (i.e., the total weight of the matrix fiber and the long reinforcing fiber), the content of such additives (in addition to the thermoplastic matrix material and the reinforcing material in the composite material) is preferably no more than about 10% of the composite material, but more or less additives may be used depending on the intended end application. It is preferred that such additives are not used or the use is limited.

[0132] In the method of the present invention, if the modified polymer composite sheet is formed from one or more composite materials, once the composite materials are provided, the modified sheets can be formed by cutting, stamping or shredding the composite materials to form and provide one or more modified sheets. This process can be completed before obtaining the sheets for use in the present method, for example, if the composite material is commercially purchased from a manufacturer before cutting or otherwise forming the modified sheets herein, or a process for forming the composite material is used, and then the composite material is cut at the same time and / or in the same position as the modified sheet shape is formed. That is, a cutting, shredding or other forming process for forming a modified polymer composite sheet using a composite material can be prepared. In addition, the modified polymer composite sheet can be cut from a polymer composite raw material (such as a unidirectional tape) and cut using a cutting device (such as described herein) Fig.24 The cutting can be done in a separate operation (a certain amount of modified flakes can be prepared and weighed in a selected amount to fill, for example, a mold cavity), or, for example, the flakes can be cut and modified so as to fall directly into the mold when the mold is filled.

[0133] The modified polymer composite sheet prepared by the present method can be provided by cutting or otherwise forming at least one outer edge feature on the outer edge portion of the sheet. Depending on the desired configuration of the modified polymer composite sheet, it can have different outer edges, which may or may not be orthogonal to each other. The outer edge feature can be formed on the entire outer edge, one or more edge portions (or extend partially or completely along some or all edge portions of the sheet).

[0134] In an embodiment of the present invention, the modified polymer composite sheet can be formed with an outer edge feature having at least two sides, which can be linear or angled edges, or have curved edge features on the edge of the outer surface of the sheet, preferably on at least a portion of the outer edge of the sheet.

[0135] The outer edge features may be produced by any suitable cutting device, including scissors, shears, knives, automatic shredders, die cutters, saws, cutting blades, drills, grinders, abrasive water jets, and laser beam cutting devices as well as those described herein. Fig.24 The device shown. Composite materials can also be used to form the modified polymer composite sheet of the present invention, which has the long reinforcing fibers and matrix materials described herein. If necessary, the surface can also be roughened after the edge features are formed to change the edge characteristics.

[0136] In certain embodiments herein, it may be preferred to form the angled sides of the outer edge features so as to be angled with each other at one end of the angled end features. Figure 3 and Figure 4 A modified polymer composite sheet 100 of the present invention is shown, which has an outer edge 114 defining a surface area A. Opposing outer surface areas 118 and 119 appear on opposite sides of the modified polymer composite sheet 100. An outer edge feature 122 is formed on the outer surface 116 of the modified sheet, located on a first edge portion 124 of the modified sheet, forming an extended triangular shape in a plan view. Similar outer edge features 122 are formed on a second edge portion 126. As shown, the second edge portion is an opposing edge portion. As shown, the angled edges 128a, 128b applicable to each outer edge feature define the shape of each outer edge feature (shown here as all identical and having an outwardly extending triangular shape).

[0137] Figure 3 and Figure 4Angled sides 128a, 128b are shown forming first outer edge feature 122a. Angled sides 128a, 128b are angled relative to each other and form an angle α having a vertex. As shown in this embodiment, angled sides 128a, 128b are connected and intersect at contact point 128c, forming vertex V1 of angle α at the outermost end of triangular outer edge feature 122a. Since each feature is identical and each outer edge feature is adjacent, angle α also represents the angle at which the outer edge features extend from each other. Adjacent features are at a single contact point P 3 (i.e., the vertices of the inwardly extending ends of the outer edge features) are connected to each other. Figure 3 and Figure 4 , angle α is most preferably an acute angle. In embodiments herein, angle α may range from about 5 ° to about 120 °. Angle α may also be from about 20 ° to about 90 °, more preferably from about 20 ° to about 60 °. In another preferred embodiment, angle α may be from about 30 ° to about 60 °.

[0138] The modified polymer composite sheet may be formed with only one or more such outer edge features (i.e., two or more) on the outer surface of the edge portion cut along the outer edge of the modified polymer composite sheet. The sheet is cut or formed so as to have outer edge features on at least a portion of the outer edge of the modified polymer composite sheet and is cut to extend in the xy plane and in the thickness of the sheet in the z direction so that the features span the opposite outer surface areas 118, 119 along the thickness t of the modified sheet 100. The outer edge features may extend through only a portion of the thickness of the sheet or may be angled in a wedge-shaped manner in the thickness direction so as to be progressive in two planes, but, as shown, the outer edge features spanning the thickness of the sheet are more desirable and easier to manufacture.

[0139] Can form not like Figure 3 and Figure 4 The outer edge features of the triangles in plan view shown have no adjacent sides and do not touch each other at a single contact point when adjacent in the pattern. Fig.23 An example of such an alternative embodiment of a modified polymeric composite sheet 100' is provided, with two outer edge features 122' having angled sides 128a', 128b', forming a trapezoidal outer edge feature 122' into an edge portion 124' on edge 114' of the modified sheet 100' extending through its thickness. The angled sides of each edge feature are angled with each other, but do not intersect at a vertex, and therefore are not triangular at their outer ends. Figure 4As shown, the angled edges are angled with respect to each other, forming an angle α' relative to each other, which has a projected vertex V2 on the outside of the end of the angled edge. The edges 128a' and 128b' are not adjacent. In addition, the outer edge feature 122' is a pattern. The pattern features are connected by linear edge portions 130' and are configured into a pattern similar to a "dovetail" design. It is also important to note that in a preferred embodiment, the pattern on one edge portion is the reverse pattern on the other edge portion, so that the trapezoid extending outward on the first edge portion is longitudinally aligned with the trapezoidal gap extending inward on the opposite edge portion (preferably in the fiber direction). The benefit of this arrangement is that the fiber length remains consistent from one end of the outer edge feature pattern to the other end.

[0140] about Figure 3 and Figure 4 (as well as Figures 3A-3C In the embodiment shown in FIG. 1 , a plurality of outer edge features 122 are arranged on two opposite outer edge portions 124, 126 in a total of four outer edge portions 124, 126, 130, 132 on the modified sheet shown. The sheet is a modified polymer composite sheet having opposite parallelogram-shaped outer surface areas. In this case, the modified polymer composite sheet is formed as a square sheet having outer edge features. Each outer edge feature 122 on the outer edge of the outer surface is made on any one of the edge portions 124, 126, and is adjacent to each other and is formed at a single contact point P. 3 contact with each other (with Fig. 7A , 7B , 16, 19 and 22-23 have different characteristics, which are Fig.23 The linear edge portion shown as 130' is connected).

[0141] exist Figure 3 and Figure 4 In the embodiment of the present invention, the angled side portions are adjacent to each other, providing a zigzag pattern Z for the edge portions 124, 126. Figure 3 and Figure 4 (as well as Figure 3A ) shows four outer edge features of the angled edge portions 124, 126 (modified sheet 100), which is based on Figure 3 and Figure 4 The configuration of is used in Examples 1, 2 and 3 herein, each angle α between adjacent outer edge portions being approximately 30°. Example 2 ( Figure 3B and 3C ) also shows and uses a similar design, respectively showing similar modified sheets 200 and 300, each sheet having a similar structure and four outer edge features as the modified sheet 100, but Figure 3B The angle α in is 60°, Figure 3C The angle α in is 90°.

[0142] Figure 5A , 5B 5C and 5C show respective modified polymer composite sheets 400, 500 and 600, which are Figure 3-3C and Figure 4 is similar to that shown in , which is a thin sheet used for the sample in Example 2, but Figures 5A-5C The flakes in FIG. 4 have eight outer edge features, each with an angle α of 30°, 60° and 90°. Two opposite edge portions of the four edge portions shown in modified flakes 400, 500 and 600 each have an outer edge feature.

[0143] Fig. 6A , 6B , 6C, 6D and 6E also show further modified polymer composite sheets 700, 800, 900, 1000 and 1100, respectively, which are also Figure 3-3C and Figure 4 The flakes in are similar, but have twelve outer edge features, each with an angle α of 30°, 60°, 90°, 5° and 15°. These flakes are also used in Example 2 herein.

[0144] In some cases, the outer edge features form a pattern but are configured so that they do not meet at a common contact point, as the angled outer edge features mentioned above typically do. When the outer edge features are non-full angle shapes, parallelograms or other shapes (where the angle α can be measured in projection or is 0°), a pattern can be formed in which adjacent outer edge features are connected by substantially linear edge portions. For example, in Fig. 7A and 7B The stepped outer edge feature structure (modified slices 1200, 1300) and Fig.16 , 19 This is shown in the structures shown in 21-23.

[0145] Apart from Fig. 7A , Figure 7B and Fig. 22 In addition to the stepped or "trough-like" rim configuration in , other examples of patterned and uniquely shaped rim features are now described and their shapes explained here. Fig.14 Additional triangular edge features are shown, with 10 consecutive triangular features on two opposing edges of the sheet shown. Fig.15 A parabolic pattern is shown with four parabolic outer edge features on opposite edges. Fig.16 Displayed Fig. 7A , 7B A variant of the rectangular slot configuration in 22, wherein the outer edge features an angled parallelogram. Fig.17 A characteristic pattern of curved outer edges is shown. Fig.15 Unlike a parabolic feature (where the sides of the feature are completely curved and meet at the ends of the curve), Fig.17 The outer edges of the features are straight, but the ends of each feature are semicircular so that each feature takes the shape of the end of a tongue depressor. Fig.18 and 20 is an example of a thin sheet with only one outer edge feature on its outer edge. These features are located on two opposite edge portions. Fig.18 In , the edge features are triangular, while in Fig. 20 In , an edge feature is a single fully curved feature. Fig.19 A pattern is illustrated of alternating outer edge feature shapes, one of which is a rectangular shape and the other of which is a bullet-shaped feature having slightly curved sides that meet at narrow arc ends. In the pattern, each feature is connected by a linear edge portion. Fig.21 A complex edge feature having an arrow configuration is provided. The arrow includes a rectangular base and a triangular arrow end, wherein the angled sides of the triangle provide a vertex end. Fig. 22 is with Fig. 7A and Figure 7B Same example of slotted construction, but in Fig. 22 Only three slot features are provided on each of the two opposing edge features. Fig.23 An example of a trapezoidal edge feature is provided, as described elsewhere in this article.

[0146] It is noteworthy that in each construction, as a preferred example, patterns are provided on opposing edge portions so that a "reverse" pattern appears, wherein an outwardly extending edge feature on one outer edge portion is longitudinally aligned (preferably in the fiber direction) with a corresponding inwardly extending sheet groove on the opposing edge surface, so that the fibers within the sheet are of uniform length in the fiber direction throughout the sheet, regardless of the length of the outer edge feature itself.

[0147] As mentioned above, different surface area shapes of modified polymer composite sheets can also be formed, such as Figure 2 The circular flakes shown have all or part of their edges 14' having the above-mentioned outer edge features. Similarly, elliptical or oval flakes can also be formed into modified polymer composite flakes in the same manner. Triangular flakes or other parallelogram or trapezoidal flakes, i.e. flakes with 3 or more edge portions, and polygonal flakes with 5 or more edge portions can also be made, wherein at least two or more edge portions of each type of modified flake have outer edge features.

[0148] like Figure 3-3C, Figure 4 and Figures 5A-5C , Figures 6A-6E , Figure 7A-7B and Figure 14-23 As shown in the different outer edge configurations in Figure 3A As shown, the long reinforcing fibers in the sheet F may be unidirectional, with the first direction D 1 The outer edge portion of the sheet extends through at least one sheet, and selected outer edge portions having outer edge features, including those forming zigzags and other patterns, can be arranged along one or more outer edge portions in the second direction D 2 Extending upward and in the direction D 1 At a certain angle β.

[0149] For example, Figure 3A As shown, the direction D in which the reinforcing long fibers F extend is 1 The two opposite edge portions 124, 126 shown have outer edge features 122, each extending substantially along the edge portion to its entire length and parallel to the width direction D along the axis yy' of the sheet 100 at an angle β. 2 , as shown in the figure, this angle is generally consistent with the direction D 1 Orthogonal, formed so that the outer edge features in the direction D 1 The angle β extends outwardly from the main surface area of ​​the modified sheet defined by the preferred edge A. However, the angle β can be varied according to different sheet designs, such as sheets with angled edges (e.g., triangular sheets, polygonal or trapezoidal sheets), or can simply include further other edge features formed on the sheet when cutting, punching, chopping or otherwise forming the modified polymer composite sheet, by providing, for example, a modified sheet with four overall parallelograms, at least one of which is cut to form a direction D that is parallel to the direction of fiber extension. 1 The angle is at a certain angle.

[0150] Although the use of angle β is optional, the edge features and / or zigzag pattern are preferably disposed parallel to the fiber direction D of the sheet having unidirectional fibers. 1 The modified sheet may be provided with outer edge features and / or zigzag or other patterns that are aligned with the fiber direction D. 1 At a certain angle.

[0151] Although in Figure 1-4 and Figure 14-23Fibers are not shown, but when viewing the modified sheet described, one skilled in the art will understand that the drawings of the modified polymeric composite sheet shown are for construction purposes and highlight the dimensional terms to show the sheet 100 prior to modification (see Figure 1 , 1A and 2) and after modification (see Figure 3 , 4 and 14-23). ​​Unmodified sheets are known in the art, and those skilled in the art will appreciate from this disclosure that the fibers can be embedded and impregnated in the composite material forming the modified sheet, and impregnated in the modified sheet after it is cut from the composite material. The fibers can extend in one or more directions, as described elsewhere herein, and are preferably unidirectional.

[0152] The outer edge features of the modified polymer composite sheet described herein provide enhanced tensile strength and / or improved impact resistance (especially at high speeds) and / or a higher failure limit to the products formed therefrom, because stress concentration at the edge of the sheet is reduced by forming edge portions having individual, grouped and / or zigzag or other patterns at the edge of the sheet.

[0153] The applicant uses the Inglis equation as an analogy to help evaluate the stress at the edge of a composite strip. In the Inglis equation, the stress can be approximated as the stress at the edge of a hole in the composite material, where the hole is elliptical in shape and the width of the hole is approximately the thickness of the unidirectionally arranged fiber reinforced composite material. The Inglis equation expresses this hole stress relationship as shown in the following equation (I), where the hole parameters a and b are approximated to the width and length of the hole, respectively, and σ max / σ is the stress concentration factor. When the composite material is under axial stress σ in the b direction, the maximum strength (stress) at the edge of the hole is σ max .

[0154]

[0155] By analogy, the applicant uses the Inglis hole edge stress equation to approximate the relationship between the thickness and tensile strength of the composite material.

[0156] This analogy compares the stress observed next to a hole present in a plate when the plate is subjected to tension. If the hole is circular, the stress concentration reaches three times the stress to which the plate is subjected. When considering a discontinuous long fiber plate under tension, the mechanical properties (strength and stiffness) drop to almost zero at the edge of the plate in the fiber direction, with reference to a standard sheet with no modified features at the edges.

[0157] For example, in a 140 micron thick sheet, the edge of the sheet represents the "stacked" thickness of more than 20 fibers (assuming a diameter of about 7 microns), and all fibers stop abruptly because all fibers are cut to the same length at the blunt edge. When forming a molded product, the surrounding sheets can form bridges at the edge of the sheet, but within a distance of about 1 sheet thickness, there are no fibers, only polymer. The strength and stiffness of the composite sheet in the fiber direction are approximately 2130 MPa and 135 GPa, respectively, for commercially available carbon / PEEK sheets. The strength and stiffness of PEEK (polymer at the edge of the sheet) used in such sheets are approximately 100 MPa and 3.7 GPa, respectively. The strength and stiffness are more than 20 times lower and can be approximated as zero performance. That is, even if there is no real "hole" at the end of a standard commercially available carbon fiber / PEEK sheet, when it becomes a resin-rich area, it is in a sense similar to a hole from the perspective of strength and stiffness.

[0158] Using the analogy of the Inglis equation, a similar hole can be viewed as an ellipse, attempting to make the sheet thinner, thereby reducing the thickness (the alpha axis of the hole) and, in turn, reducing the stress concentration factor. However, in the present invention, providing improved edge features, such as providing a zigzag pattern, is essentially a progressive edge or soft transition from the location of high carbon fiber characteristics within the sheet to the end of the outer edge feature (such as the point of the triangular feature) extending outward, where the characteristics again approach zero. Again using the analogy of the Inglis equation, this is like increasing the axis b of the ellipse and reducing the stress concentration factor. Therefore, instead of thinning the sheet to increase strength, the thickness is retained, the fiber length and number are retained, but the edge becomes progressive while the stress concentration factor is still reduced. This makes the transition between the zero characteristics at the outer edge of the sheet and the high strength characteristics inside the sheet less drastic and more gradual. In some cases, changing a in the equation may be more efficient, but it is not cost-effective from a manufacturing perspective.

[0159] In applicant's U.S. Patent Application No. 10,160,146, applicant has attempted to use discontinuous long reinforcing sheets of various lengths. However, while such composite tapes provide good shaped articles and isotropy, the strength of the final shaped articles formed from such composite tapes is not sufficiently improved. Based on applicant's data, applicant's theory is that the "length" parameter b provided for each modified sheet is very important for the final improvement in strength of the article formed from the modified sheet and the enhancement of strength isotropy. Not only is the strength significantly improved, but also the impact resistance (especially the impact resistance under high-speed impact) and fatigue limit are improved. Example

[0160] In further exploring the effects of the present invention, it was further discovered that the number of outer edge features and the angle or nature of the outer edge feature edges can be modified or changed to achieve the best effect in the article formed from the modified polymer composite sheet, that is, the degree to which the strength and / or failure limit and / or high-speed impact resistance is increased by changing the features. This is demonstrated in the following examples. Each of the examples herein is intended to help illustrate the present invention, but should not be considered limiting.

[0161] Example 1

[0162] Unidirectional composite tapes having continuous long reinforcing fibers extending in the length direction were used in the following examples. Specifically, three commercially available polyetheretherketone composite tapes provided by Solvay, Barrday, and Tencate (Toray) were tested. The samples were made of AS4 carbon fiber (C / PEEK) (Samples A, B, and C) and were cut into 0.5 inch by 0.5 inch rectangular sheets on the outer surface area defined by the edges of the sheet, with Figure 1 The prior art sheet is similar to that in FIG. Figure 3B As shown, the modified polymer composite sheet is formed of the same material and has the following features on its two opposite edges: Figure 3 and Figure 4The zigzag pattern and outer configuration shown. On the first of the two opposing edges, the zigzag pattern includes four outwardly extending outer edge features with angled sides forming a vertex (thus presenting a triangle) with an angle α of 30° between adjacent pairs of outer edge features. On the other second pair of edges, the zigzag pattern is positioned such that at the angled edge features extending outwardly on the second pair of edges, their vertices are axially aligned with adjacent junctions between two adjacent edge features on the first pair of edges. Thus, the second edge includes three edge features whose triangular shapes are exactly the same as those formed on the first edge, with an angle of 30° (angle α) between adjacent features, but at the end of the second edge, there are two narrower local edge features, each of which is spaced 30° apart from the three adjacent features. These local features together constitute approximately half of the complete edge features, just like the rest of the pattern, thereby providing the benefit of a total of four outer edge features, each of which has two sides with an angle in the middle. The outer edge features form a pattern on each opposing edge, and these patterns extend over the edge length of the 0.5 inch size of the sheet. The direction of extension of the carbon fibers is approximately orthogonal (angle β is 90°) to the two opposite edges having the outer edge features. Due to the pattern formed on the opposite edges, the length measured directly from one opposite edge through the sheet to the other opposite edge is approximately the same along the two opposite outer edges having the outer edge features, thereby maintaining a continuous fiber length, but providing a gradual (transitional) exposure of the fiber ends due to the cutting of the pattern into the sheet.

[0163] The standard thickness of the composite tapes used was 0.14 mm, and the fiber content was approximately the same, 61%. The sheet material in the modified polymer composite sheet was molded into a 0.1 inch thick plate with a size of 12 inches by 12 inches using a compression molding process, and cut into "dog bone" shaped samples with a width of 1 inch in the measurement area. At least 20 samples were tested for each configuration using the tensile test method of the American Standard Test Method (ASTM) standard number ASTM D3039-17.

[0164] The forming process involves forming the sheets by cutting the UD tape into repeatable sheet geometries using a cutting device. The required number of sheets are weighed and filled manually (but can also be filled by a robotic system) so that the sheets are evenly spread into a 12 inch x 12 inch square mold cavity. The mold is heated to about 400°C in a hot press, but processing temperatures of about 360°C to about 430°C can also be used. A pressure of about 100 bar is applied to the material. A processing pressure of about 60 bar to about 150 bar can also be applied to the material. The material is then cooled using a cold press at the same pressure. The thickness of the produced sheet is about 0.1 inches, and each sheet is processed into seven (7) dog bone samples with a width of 1 inch.

[0165] Fig.11 It was shown that when the flakes were modified, the tensile strength of the articles formed from the flakes was improved, regardless of the raw material supplier. Figure 1 The flakes of the unmodified square flake configuration shown were modified, with materials from all three sources showing increases of about 30% to about 40%. In the figure, commercially available samples of molded parts made from unmodified flakes without outer edge features are identified in the unmodified state as "0-0-A", "0-0-B" and "0-0-C". These commercially available samples are square in shape and have a configuration similar to Figure 1 and Figure 1A Similar. The modified samples carry the commercially available sample identifiers (A, B, or C), but note the total number of outer edge features (N) used on two opposing edge portions of the modified sheet and the angle between the outer edge features, e.g., sample A has four outer edge features on each of two opposing outer edge portions extending the length of the outer edge of the square surface area defined by the outer edge, the outer edge features are triangular and adjacent, and the angle between each feature is 30°. Therefore, they are designated N4-30-A. The unmodified version of sample A is designated 0-0-A.

[0166] Example 2

[0167] In this example, two commercially available composite (C / PEEK) unidirectional tapes containing AS4 carbon fibers were used to make various samples of the present invention. The two tapes were from Solvay and Tencate (Toray). The number, shape and angle of the outer edge features of the modified polymer composite sheet samples of the present invention varied. The unidirectional composite tape was chopped into pieces to form a sheet, so that the modified sheet formed was a 0.5 inch x 0.5 inch modified sheet containing long fibers from the tape.

[0168] In addition to the samples of the present invention, control samples of the prior art were also used. The outer edge of the control sample D was a square with a surface area of ​​0.5 inches x 0.5 inches defined by its outer edge, and the design was as follows: Figure 1 Shown is an unmodified sheet. Another control sample E is a beveled sheet having linear edges with the beveled edge at a 45° angle.

[0169] Thirteen different samples of the present invention were made, each with a different outer edge feature and / or number of features. All samples of the present invention were oriented similarly, i.e., the outer edge features were located on two opposite outer edge portions, the modified sheet was an overall parallelogram, wherein the edge features were as described above, and the outer edge portions having the outer edge features formed a β angle of 90° with the fiber extension direction of the modified sheet.

[0170] Some of the inventive samples in this example are similar to the modified polymer composite sheets in the inventive samples of this example 1, i.e., they have "triangular" edge features that form a zigzag pattern, including an angle α between adjacent edge features on opposite edge portions. In the design, the "teeth" are staggered on the opposite edges so that the apex of the edge features on the first opposite side passes through the sheet in the fiber direction and is aligned with the contact point between two adjacent edge features on the second opposite edge of the modified sheet, so that the fiber length is generally consistent along the modified sheet.

[0171] The naming of these samples refers to the angle α between adjacent outer edge features and the number of outer edge features (in this case, "teeth") extending outward. For example, in the first inventive sample 30-4, "30" represents the angle α between the outer edge features, and "4" represents the number of outer edge features on each opposing outer edge portion. In other inventive samples with triangular edge features, the angle and number of outer edge features are also changed and named accordingly.

[0172] In the "step cut" variation, samples of the present invention were also formed using rectangular outer edge features. Because these features are rectangular, their sides are connected by straight sections, and there are no "vertices" formed on the outer edge features, so the angle α between them is 0°. Instead of each feature being connected to the next outer edge feature at a single point like a triangular outer edge feature, it is connected by a generally straight edge portion with a width equal to the width of the step outer edge feature. Each modified sheet has a series of rectangular "teeth" that appear elongated after cutting. The fibers also extend along the feature direction to form an angle β of 90° and are orthogonal to the extension direction of the opposing outer edge portion, including the outer end feature. These patterns have similar alignment features on each opposing edge feature staggered so that the outwardly extending rectangular edge feature on the first outer edge portion is aligned with the space between the two outwardly extending outer edge portions on the second opposing edge portion. These samples are identified as samples 6X2, where "6" is the cutting depth (mm) and "2" is the width (mm) of the rectangular outer edge feature.

[0173] Identical modified sheets were made for each structure using two commercially available tape materials, and the data for each material were averaged to provide the data presented herein.

[0174] Figure 3B-3 D, 5A-5C, 6A-6E and 7A-7B represent Fig. 9The modified flakes of the present invention shown in the table are samples 30-4, 60-4, 90-4, 30-8, 60-8, 90-8, 30-12, 60-12, 90-12, 5-12, 15-12, 6X 2 and 6X 1. These samples are also shown in Figures 3A-3C (sheets 100, 200 and 300), Figures 5A-5C (sheets 400, 500 and 600), Figures 6A-6E (Flake 700, 800, 900, 1000 and 1100) and Figure 7A-7B (sheets 1100 and 1200).

[0175] Fig. 8A and 8B Control samples D (square cut with unmodified edge features) and E (angled cut with unmodified edge features) are depicted.

[0176] Each of the inventive samples and the control samples were tested using ASTM D3039-17. Fig. 9 The average tensile strength of articles formed from all modified sheet geometries is shown. All samples of the present invention tested were modified to provide outer edge features and showed an increase in tensile strength after providing the modified edge features.

[0177] The control sample E (bevel cut) has increased edge strength compared to the control sample D. While it is known that using longer fibers (and therefore longer flakes in the fiber direction) can produce similar reinforcement, it is generally found that longer fibers present more difficulties during processing.

[0178] In contrast, the modified edges of the outer edge features of the samples and modified polymer composite sheets used in the present invention retain the same fiber length as the original sheet and retain the ease of processing of the square sheet while also benefiting from the enhanced strength. Fig.10 As further illustrated, the deeper the edge modification of the tested samples of the present invention, the greater the increase in tensile strength. The formed articles show that the average tensile strength of the sheets formed in the samples of the present invention is higher than the expected strength of the unmodified sheets, and the changes in the sheet design in the samples of the present invention show that the improvement and strength characteristics can be changed according to the configuration or number of outer edge features and / or the adjustment of the angle or spacing between the outer edge features. Therefore, the methods of the present invention can be used to adopt and change more or less outer edge features, changes in shape or angle, and the depth of the modified edge features cut into the sheet to make articles of manufacture using the modified sheets. These methods can all show good results, but can also be adjusted to achieve the best improvement or strength level for a specific polymer matrix material and the expected final application.

[0179] Example 3

[0180] The effects of hail are of particular concern to the aerospace industry, as hail can strike any exposed part of an aircraft at speeds of up to 250 m / s. The ability of a material to resist projectile impact, especially high-velocity projectile impact, is important in providing composite materials suitable for aircraft construction. Impact resistance is also important in areas subject to large hail or large hail from severe storms with high-velocity winds, which can cause significant property damage or loss of life.

[0181] Impact resistance, particularly high-speed impacts, can be evaluated by studying the impact of artificial hail on test specimens and actual parts. To this end, the behavior of materials formed from modified polymer composite sheets according to the present invention was evaluated using a modified sheet formed from the inventive sample 30-4 in Example 2, i.e., a 0.5 inch x 0.5 inch sheet, which is a square structure formed from a 0.5 inch wide composite tape, and which includes a total of four outer edge features (aligned to offset the common point between an outer edge feature extending outwardly on a first outer edge portion and two adjacent outer edge features on an opposite outer edge portion), with adjacent outer edge features forming a triangle with an angle of 30° between them. A comparative sheet with unmodified edges (no edge features) similar to the control sample D of Example 2 was also used in this example.

[0182] The modified polymer composite sheet was formed using the above molding process to form a sheet with a size of 12 inches x 12 inches and a thickness of 0.15 inches. Each board was cut in half to form two 12-inch x 6-inch boards. The boards were then placed in Fig.12 In the test fixture shown. On both sides of the long side of each plate, clamped with rubber clamps along a distance of 1 inch, leaving a width of 4 inches between the clamps. Each plate is tilted 30° from the horizontal extension plane. Then a hail with a diameter of 50mm is hit at the center of the inclined plate with a horizontal trajectory at a temperature of -18℃ and a speed of 100 to 300 meters / second.

[0183] After impact, the panels were inspected and the degree of damage was rated as: (i) no visible damage; (ii) visible damage and / or (iii) material loss. Fig.13 A graphical illustration of the data is shown, with each test marked as a point on the graph shown. The results show that the modified polymer composite sheet is significantly improved over the straight-cut sheet. Comparing the panels formed from the modified sheet samples to the panels formed from the unmodified sheet control samples, the speed at which damage occurred was increased by about 75 meters per second, while material shedding did not occur until the speed was increased by about 100 meters per second.

[0184] Example 4

[0185] In order to further evaluate the fatigue resistance of the present invention, unnotched tensile specimens were manufactured and subjected to fatigue cycles under the condition of stress ratio R=0.1. Fig.25 The test results are shown with the applied stress level in MPa versus the number of cycles until the specimen failed. Some specimens did not fail, indicated by different markings.

[0186] In this example, unmodified square sheets (0.5 inch side length) without edge features were used to make test specimens (Comparative Example X), while the sheets formed in Example 1 were used to make test specimens of the present invention (Sample Y of the Present Invention). Both sheets were cut from the same carbon and PEEK (C / PEEK) unidirectional tape. The modified sheet used to make Sample Y of the Present Invention was modified to have four "triangular" outer edge features ("teeth") forming a zigzag pattern, with an angle α between each feature of 30°, and a square geometry (size of 0.5 inches), as shown in Example 1. These features are located at two opposite outer edge portions, with an angle α between adjacent outer edge features. The direction of the fibers is between the edges with edge features and is orthogonal to the extension direction of the edges with edge features (i.e., angle β of 90° as described above). The teeth are staggered on the opposing edges in a design so that the apex of an outer edge feature of a first opposing side is aligned with the contact point between two adjacent outer edge features of a second opposing side of the modified sheet in the fiber direction across the sheet, thereby making the fiber length substantially uniform along the modified sheet.

[0187] The fatigue life of Control Sample X and Inventive Sample Y was evaluated using unnotched tensile specimens formed from unmodified (Control Sample X) and modified (Inventive Sample Y) sheets. Fig.25 The data in show the fracture or exhaustion locations for various unnotched tensile specimens. Fig.25 The linear fit results are shown for each set of data points for samples X and Y. Based on the linear fit results, the high cycle fatigue life is significantly improved by about 59% when the same composite material is used but the standard flakes are replaced with modified flakes.

[0188] Example 5

[0189] In this example, unmodified and modified flakes formed according to Example 4 were used to prepare high-speed hail impact test samples (i.e., control sample X and inventive sample Y). The control sample X composite sample was made with unmodified flakes, while the inventive sample Y composite sample was made with modified flakes, each of which was 0.5 inch square. Another inventive composite material (inventive sample Z) was prepared using modified flakes, which was made of the same composite material as inventive sample Y, but had a rectangular shape with a length (dimension along the fiber direction) of 1.0 inches. The width dimension (0.5 inches) in the orthogonal width direction was the same as inventive sample Y.

[0190] Using the apparatus and method of Example 3 (including the parameters mentioned in Example 3), samples of control sample X and inventive samples Y and Z were tested. Fig.26 Impact performance is shown, where panels were examined and damage was rated as: (i) no visible damage; (ii) visible damage and / or (iii) material loss. Fig.13 The results shown are similar to those shown in , which show that the modified composite sheet of the inventive sample Y is significantly improved compared to the unmodified (straight cut) sheet of the control sample X. The rate of damage occurrence in the inventive sample Y is significantly increased compared to the control sample X, and material release does not occur until about 225m / s. Among the tested samples, the inventive sample Z performed slightly better than the inventive sample Y in terms of visible damage and no obvious material shedding. The results show that longer sheets can provide further improvements, and the beneficial properties obtained by the progressive end of the modified sheet edge feature are cumulative to the gains that can be obtained by using longer fibers.

[0191] As shown in the above disclosure and examples, the articles formed by the modified polymer composite sheet and / or using the method described herein can be of various types and can vary depending on the selected composite material. For example, the various modified polymer composite sheets described herein can be used to form articles as devices, components or parts, and can be used in various terminal applications. For example, these articles can be made into high-strength, lightweight aircraft parts, medical devices, containment shells and / or parts for high-temperature and high-pressure terminal applications (such as semiconductors, fluid processing or downhole oilfield conditions). Aircraft parts such as brackets, covers or fairings can be formed, or cabin side wall accessories can be formed. Other terminal applications include devices, components or parts used in robots, automobiles, semiconductors or sports industries, such as robot legs, housings for automobile shock absorbers, wafer handling tools in semiconductor processing, and bicycle parts.

[0192] Can be by thermoforming or curing mode, according to the type of matrix polymer, the multiple modified polymer composite thin slices provided according to the inventive method are directly made into products, or the modified polymer composite thin slices are mixed with other types of thin slices to obtain different effects to form products. When using the second or other types of thin slices, these thin slices can be thin slices modified according to the method of this article, or unmodified thin slices. In addition, when using the second or other types of thin slices and modified thin slices as described herein, the polymer matrix material and / or reinforcing fibers can be the same or different with the modified thin slices mixed therewith. Preferred molding conditions are as described above.

[0193] As supported by the examples, the present invention also provides a method of increasing the average tensile strength and / or impact resistance, especially one or more of high-speed impact resistance, of an article formed using a modified polymeric composite sheet having outer edge features, as compared to an article formed from a standard unmodified composite sheet formed so as to have a polymer matrix material and reinforcing long fibers extending through the sheet. The improvement results from providing one or more of the outer edge features described above to the outer edge portion of the modified polymeric composite sheet provided herein using the above-described techniques. The fatigue limit of such an article can also be increased using the modified sheets and methods described herein.

[0194] Those skilled in the art will appreciate that the above embodiments may be modified without departing from the broad inventive concept of the present invention. Therefore, it is to be understood that the present invention is not limited to the specific embodiments disclosed, but is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A method for providing a modified polymer composite sheet for forming an article, comprising: (a) providing a composite material having at least one polymer matrix material and long reinforcing fibers of a first fiber material extending through the polymer matrix material; and (b) at least one sheet formed from the composite material, wherein the at least one sheet comprises an outer surface having an outer edge, a portion of the outer edge being configured to provide at least one outer edge feature to the outer edge of the at least one sheet, thereby providing a modified polymer composite sheet. 2 . The method of claim 1 , further comprising forming at least one sheet by cutting the composite material.

3. The method according to claim 2, characterized in that The at least one sheet is cut by a cutting device.

4. The method according to claim 1, characterized in that: The composite material is in a form selected from the group consisting of a tape, a plate and a sheet.

5. The method according to claim 1, characterized in that The long reinforcing fibers in the composite material are unidirectional.

6. The method according to claim 5, characterized in that The long reinforcing fibers in the composite material are continuous long reinforcing fibers.

7. The method according to claim 1, characterized in that The composite material is in the form of a tape, and the long reinforcing fibers are unidirectional continuous long reinforcing fibers.

8. The method according to claim 1, characterized in that The at least one outer edge feature has at least two angled sides.

9. The method according to claim 8, characterized in that The at least two angled sides of the outer edge feature are angled with respect to each other at an angle of about 5° to about 120°.

10. The method according to claim 9, characterized in that The at least two angled sides of the outer edge feature are angled with respect to each other at an angle of about 20° to about 90°.

11. The method according to claim 10, characterized in that At least two angled sides of the outer edge feature are angled with respect to each other at an angle of about 20° to about 60°.

12. The method according to claim 11, characterized in that The at least two angled sides of the outer edge feature are angled with respect to each other at an angle of about 30° to about 60°.

13. The method according to claim 12, characterized in that At least two angled sides of the outer edge feature are adjacent and together form an apex of an angle at a contact point between the at least two angled sides.

14. The method according to claim 8, characterized in that There are multiple outer edge features.

15. The method according to claim 14, characterized in that At least two angled sides of each outer edge feature are adjacent and together form an angled vertex at a contact point between the at least two angled sides, wherein at least two outer edge features among the plurality of outer edge features are also adjacent, so that the outer edge portion having at least one edge feature comprises a zigzag pattern.

16. The method according to claim 15, characterized in that The outer edge of the at least one sheet includes at least three outer edge portions, and at least two of the outer edge portions include a zigzag pattern.

17. The method according to claim 15, characterized in that The long reinforcing fibers in the at least one sheet are unidirectional and extend through the at least one sheet in a first direction, and the outer edge portion comprising the zigzag pattern extends in a second direction, wherein the second direction is angled with the first direction.

18. The method according to claim 17, characterized in that The angle between the second direction and the first direction is approximately 90°.

19. The method according to claim 18, characterized in that The angle between the second direction and the first direction is about 60° to about 90°.

20. The method according to claim 1, characterized in that The at least one outer edge feature is configured to have a shape selected from a triangle, a parabola, a parallelogram, a bell, a bullet, an arrowhead, and a trapezoid, and when there is more than one outer edge feature, each outer edge feature may be the same or different.

21. The method according to claim 20, characterized in that The at least one outer edge feature is a parallelogram having a rectangular shape.

22. The method according to claim 20, characterized in that The outer edge portion having edge features has two or more outer edge features, and these outer edge features together form a pattern.

23. The method according to claim 22, characterized in that The at least one sheet has four outer edge portions, two of which are opposing outer edge portions, and each of the two opposing outer edge portions has a pattern formed thereon so that the pattern extends along substantially all of the two opposing outer edge portions so that a distance across the at least one sheet measured longitudinally between the two opposing edge portions remains substantially consistent throughout the pattern.

24. The method according to claim 1, characterized in that The polymer matrix material is a thermoplastic and is one or more of polysulfone, polysulfide, polyimide, polyamideimide, polyamide, polyarylene polymer, fluoropolymer, and combinations and copolymers thereof.

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

26. The method according to claim 24, characterized in that The polymer matrix material is a fluorine-containing polymer, which 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 perfluoroolefin, polychlorotrifluoroethylene, ethylchlorotrifluoroethylene, ethyltrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, and combinations and copolymers thereof.

27. The method according to claim 1, characterized in that The polymer matrix material is a thermosetting polymer and is one or more of a thermosetting elastomer, an epoxy resin, a thermosetting biscitraconimide, a bismaleimide, a bismaleimide / triazine / epoxy resin, a cyanate ester, a cyanate resin, a furan resin, a phenolic resin, a urea-formaldehyde resin, a melamine formaldehyde resin, a phthalocyanine resin, a polybenzoxazole resin, an acetylene-terminated polyimide resin, a silicone, a polytriazine, a thermosetting polyvinyl ester, a thermosetting polyurethane, a polytetrafluoroethylene, a melamine, a polyalkyd resin, and a xylene resin.

28. The method according to claim 1, characterized in that The long reinforcing fibers in the at least one sheet are one or more of inorganic fibers, ceramic fibers, glass fibers, graphite fibers, carbon fibers, thermoplastic fibers, thermosetting fibers, and combinations thereof.

29. The method according to claim 1, characterized in that The outer edge of at least one sheet defines a surface area having an overall shape on the outer surface of at least one sheet, the overall shape being generally a triangle, a polygon having at least five sides, a circle, a parallelogram or a trapezoid, and at least one outer edge feature is formed on at least one edge portion of the surface area shape.

30. The method according to claim 29, characterized in that The surface area defined by the outer edges is a parallelogram selected from a square, a rectangle and a rhombus.

31. The method according to claim 29, characterized in that There are a plurality of sheets, each sheet having a surface area defined by an outer edge of the sheet on an outer surface of the sheet, and having a thickness measured along the outer edge of each sheet in a plane normal to the surface area of ​​the sheet, wherein the average outer surface area of ​​the plurality of sheets is about 20 mm 2 To about 650mm 2 , the average thickness of the plurality of sheets is from about 0.05 mm to about 0.25 mm.

32. The method according to claim 31, characterized in that The average outer surface area of ​​the plurality of sheets is about 150 mm 2 To about 170mm 2 , the average thickness of the plurality of sheets is from about 0.1 mm to about 0.20 mm.

33. The method according to claim 1, characterized in that When a plurality of modified polymer composite sheets having outer edge features are used to form an article, the average tensile strength of the formed article is increased by at least about 30% compared to an article formed using a plurality of sheets formed from the same material, having the same overall shape and size, but lacking the outer edge features.

34. The method according to claim 33, characterized in that The average tensile strength of an article formed using the plurality of modified polymer composite sheets is increased by at least about 40% to about 60%.

35. The method according to claim 1, characterized in that The at least one outer edge feature has at least two angled sides, and the at least two angled sides of each outer edge feature on at least one modified sheet are adjacent and together form an angle vertex at the contact point between the at least two angled sides, wherein there are multiple outer edge features on at least one modified polymer composite sheet, and at least two of the multiple outer edge features are also adjacent, so that the outer edge portion of at least one modified polymer composite sheet contains a zigzag pattern.

36. The method according to claim 35, characterized in that There are about 2 to about 12 outer edge features in a zigzag pattern on at least one modified polymer composite sheet.

37. The method according to claim 36, characterized in that There are about 4 to about 8 outer edge features in a zigzag pattern.

38. The method according to claim 36, characterized in that The at least one modified polymer composite sheet includes at least three outer edge portions, at least two of which have a zigzag pattern.

39. The method according to claim 38, characterized in that There are about 4 to about 8 outer edge features in a zigzag pattern.

40. An article formed by thermoforming or curing a plurality of modified polymeric composite sheets formed according to the method of claim 1.

41. The article according to claim 40, characterized in that The article is a component, device or part for high temperature and / or high pressure end applications or for aircraft, medical equipment, robotics, automobiles, semiconductors or sports end applications.

42. The article according to claim 41, characterized in that The product is a bracket, a cover, a fairing or a cabin side wall accessory used on an aircraft.

43. The article according to claim 40, characterized in that The article is a containment vessel.

44. The article according to claim 40, characterized in that The article is formed by molding or curing a plurality of modified polymer composite sheets together with unmodified polymer composite sheets, wherein the unmodified polymer composite sheets may be the same as or different from the at least one modified polymer composite sheet formed by the method of claim 1.

45. The article according to claim 44, characterized in that The unmodified polymer composite sheet contains the same polymer matrix material and the same long reinforcing fibers as at least one modified polymer composite sheet formed by the method of claim 1 .

46. ​​A method of increasing one or more of average tensile strength and impact resistance of an article formed from a composite sheet having at least one polymer matrix material and long reinforcing fibers extending through the polymer matrix material, wherein the composite sheet comprises an outer surface having at least one outer edge, the method comprising: providing a plurality of modified polymer composite sheets, wherein each of the modified polymer composite sheets has an outer edge feature along an outer edge portion of the sheet; and A plurality of sheets of the modified polymeric composite material are used to form an article.

47. The method according to claim 46, characterized in that The impact resistance of the article formed using the modified polymer composite sheet is high-speed impact resistance.

48. A modified polymer composite sheet for preparing an article, comprising: an outer surface having an outer edge thereon, wherein the outer edge defines an outer surface region on the outer surface, the modified polymeric composite sheet having a thickness along the edge extending in a direction generally orthogonal to the outer surface region defined by the edge; polymer matrix material; long reinforcing fibers in a polymer matrix material; and At least one outer edge feature is disposed on an outer edge portion of the modified polymeric composite sheet.

49. The modified sheet according to claim 48, characterized in that The shape of the outer edge feature is selected from the group consisting of a triangle, a parabola, a parallelogram, a bell, a bullet, an arrow and a trapezoid.

50. The modified sheet according to claim 49, characterized in that There is more than one outer edge feature, and each outer edge feature is identical.

51. The modified sheet according to claim 50, characterized in that There are two or more outer edge features that together form a pattern.

52. The modified sheet according to claim 48, characterized in that The long reinforcing fibers are unidirectional in the polymer matrix material.

53. The modified sheet according to claim 48, characterized in that The modified polymer composite sheet is formed of a polymer composite material having unidirectional continuous long reinforcing fibers.

54. The modified sheet according to claim 48, characterized in that The outer edge feature has at least two sides that are angled with each other at an angle of about 5° to about 120°.

55. The modified sheet according to claim 54, characterized in that The outer edge feature has at least two sides that are angled with each other at an angle of about 20° to about 90°.

56. The modified sheet according to claim 55, characterized in that The outer edge feature has at least two sides that are angled with each other at an angle of about 20° to about 60°.

57. The modified sheet according to claim 56, characterized in that The outer edge feature has at least two sides that are angled with each other at an angle of about 30° to 60°.

58. The modified sheet according to claim 54, characterized in that The two angled sides are adjacent and together form a vertex of an angle at a contact point between at least the two angled sides.

59. The modified sheet according to claim 58, characterized in that There are a plurality of outer edge features, each outer edge feature having at least two angled sides.

60. The modified sheet according to claim 59, characterized in that At least two of the plurality of outer edge features are also adjacent such that at least a portion of an outer edge of each of the plurality of modified polymer composite sheets having outer edge features comprises a zigzag pattern.

61. The modified sheet according to claim 60, characterized in that Each of the modified polymer composite sheets includes at least three outer edge portions, at least two of which have a zigzag pattern.

62. The modified sheet according to claim 61, characterized in that The long reinforcing fibers in each modified polymer composite sheet are unidirectional fibers and extend through the modified polymer composite sheet in a first direction, and at least a portion of the outer edge of each sheet containing a zigzag pattern extends in a second direction, wherein the second direction is at a certain angle to the first direction.

63. The modified sheet according to claim 62, characterized in that The second direction is orthogonal to the first direction.

64. The modified sheet according to claim 63, characterized in that An angle formed between the second direction and the first direction is about 60° to about 90°.

65. The modified sheet according to claim 48, characterized in that The polymer matrix material is a thermoplastic and is one or more of polysulfone, polysulfide, polyimide, polyamideimide, polyamide, polyarylene polymer, fluoropolymer, and combinations and copolymers thereof.

66. The modified sheet according to claim 65, characterized in that The polymer matrix material is a polyarylene polymer and is one or more of polyetherketone, polyetheretherketone, polyetherketoneketone, and combinations and copolymers thereof.

67. The modified sheet according to claim 48, characterized in that The long reinforcing fibers in the composite material are one or more of inorganic fibers, ceramic fibers, glass fibers, graphite fibers, carbon fibers, thermoplastic fibers, thermosetting fibers and combinations thereof.

68. The modified sheet according to claim 48, characterized in that The modified polymer composite sheet has multiple outer edge features, each of which includes at least two angled edges, and at least two of the angled edges are adjacent and form an angled vertex at the contact point between the at least two angled edges. At least two of the multiple outer edge features are also adjacent, so that at least one edge portion of the outer edge with the outer edge feature on each sheet includes a zigzag pattern.

69. The modified sheet according to claim 68, characterized in that There are about 2 to about 12 outer edge features in the zigzag pattern.

70. The modified sheet according to claim 69, characterized in that There are about 4 to about 8 outer edge features in the zigzag pattern.

71. The modified sheet according to claim 68, characterized in that The modified polymer composite sheet includes at least three outer edge portions, at least two of which have a zigzag pattern.

72. The modified sheet according to claim 71, characterized in that There are about 4 to about 8 outer edge features in the zigzag pattern.

73. An apparatus for forming a sheet of a modified polymer composite material for forming an article, comprising: a feeder for controllably feeding a portion of a polymer composite material configured and dimensioned for forming a sheet, the composite material comprising at least one polymer matrix material and long reinforcing fibers extending through the polymer matrix material in the polymer composite material; and A movable and controllable cutting device, which operates as a cutting table to cut a portion of a polymer composite material fed by a feeder into thin sheets, and the device includes one or more removable cutting templates, which are configured to provide at least one outer edge feature on the edge portion of the thin sheet cut from the cutting device.

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

75. The apparatus according to claim 73, characterized in that The different cutting templates may be used to provide different edge features to different edge portions of the cut sheet.

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