WO2000064663A2

WO2000064663A2 - A laminate article and a process for manufacturing it

Info

Publication number: WO2000064663A2
Application number: PCT/US2000/009167
Authority: WO
Inventors: Raymond Hans Glaser
Original assignee: AlliedSignal Inc
Current assignee: Honeywell International Inc
Priority date: 1999-04-08
Filing date: 2000-04-07
Publication date: 2000-11-02
Anticipated expiration: 2001-10-08
Also published as: AU6197100A; WO2000064663A3

Abstract

The present invention is a laminate article having at least two layers in which each of the lasers comprises a plurality of units of unidirectional, parallel fibers embedded in a polymeric matrix, each of the units having a width of at least about 7.5 inches (about 191 millimeters), the fibers are essentially continuous within the at least two layers and the fibers have a fiber orientation angle of between 0° and 90° with respect to the longitudinal direction of the laminate article. A method to manufacture the inventive laminate article is also taught. The inventive laminate article is useful in ballistic resistant articles.

Description

A Laminate Article and a Process for Manufacturing It

Related Applications

This application claims the priority date of provisional application Serial No. 60/128280, filed 4/8/99.

Background of the Invention

1 . Field of Invention

This invention relates to articles which are laminates of fiber-reinforced polymeric composite layers. Specifically, the invention relates to articles which have at least two composite layers in which the fiber reinforcement is oriented obliquely with respect to the longitudinal axis of the article and which fiber is not cut in the manufacture of the article but rather, is continuous in the cross-plied laminate article. In addition, a method is disclosed to make such a laminate article continuously.

2. Description of the Related Art

Laminates of unidirectional fiber-reinforced polymeric composite sheets are well known in the art and have a diverse array of uses. For instance, such laminates find use as components of: ballistic-resistant articles, tires for vehicles, conveyor belts, and mailing packages. The types of fibers and polymers used in the manufacture of such fiber-reinforced sheets are also quite diverse and are typically chosen with consideration to the desired end use for such articles. These laminated articles are commonly stacks of unidirectional fiber-reinforced composite panels in which the fiber in adjacent stacked panels has an equal and opposite fiber orientation angle with respect to the longitudinal axis to provide balanced reinforcement. The composite panels are then made to adhere to one another, for example, by curing of the polymeric sheet material by application of pressure and heat. In making the fiber-reinforced composite sheets used in building such laminates, it is well known to make the sheets which are planar strips having an essentially endless longitudinal direction to which the unidirectional fiber is parallel and in which the fiber is continuous in the longitudinal direction.

U. S. Patent 5,535,801 discloses a tire belt which is a multiple layer folded laminate of continuous, unidirectional fiber-reinforced material. The tire belt is made of a narrow, tire cord-reinforced ribbon, preferably 5 to 15 mm wide, which is spirally zigzagged to create the tire belt. The preferred cord for reinforcement is aromatic polyamide. This design is advantageous in having no cut fibers at the longitudinal edges of the belt. However, folding the narrow ribbon into the desired zigzag design involves extensive manipulation of the ribbon and would likely be time-consuming if such a technique was used to generate much longer lengths of a multiple layer laminate. Furthermore, as a result of the narrow ribbon width taught, the composite has a large number of joints of abutted or slightly overlapped edges in each layer of the laminate. The frequency of joints may be disadvantageous in some uses of such a composite. A similar zigzag composite is also disclosed in U. S. Patent 5,427,167.

Commonly-assigned U. S. Patent 5,173,138, hereby incorporated by reference, teaches a method and apparatus for the automated production of a cross-plied material. This process entails sequentially layering discontinuous plies of material copianariγ on a first, continuous ply such that the longitudinal axes of the fibers in the two plies are not parallel. Thus, a cross-plied product can be formed in which one ply has continuous, uncut fiber reinforcement and the second ply in which the fibers are cut. The cross- plied product can be formed continuously, albeit in a stepwise manner, using an automated process, and can be rolled up in a bolt for subsequent use.

U. S. Patent 5,766,725 discloses a single layer composite web of parallel fibers in a matrix in which the fibers in the composite layer run at an angle differing from 0° relative to the lengthwise direction of the web. The linear structure of the composite web is a series of joined-up and connected web parts which parts are obtained by cutting them out of a web having unidirectional fibers which are parallel to the longitudinal axis of the web. The cutting is angled with respect to the longitudinal axis and the cut parts are joined-up and connected in such a way that the cut sides form the longitudinal sides of the composite web. Thus, this composite web contains cut fiber ends along the entirety of its two parallel longitudinal sides. A method of making this composite web is also disclosed. The method involves multiple steps including cutting out of the web parts and assembly of web parts into the single layer composite web having fibers running at an angle differing from 0° relative to the lengthwise direction of the web. To form a multiple layer composite, one then takes this single layer composite web and assembles it with another layer of web to form a two layer composite, for instance. This method thus involves cutting and multiple assembly steps to yield at least a two layer composite and the resultant composite has at least one layer containing cut fibers. Although such a process can be automated, it also is not entirely continuous in that assembling the cut out web parts into the composite web is a stepwise process.

The problem to be solved is therefore a laminate article in which unidirectional, parallel fibers embedded in a matrix are oriented at greater than 0° with respect to the longitudinal direction of the composite and are cross-plied with respect to an adjacent layer. A method of manufacturing such a composite continuously, in an automated process and without the attendant problems of cutting out pieces and re-assembling such cut pieces, or alternately, zigzagging a narrow ribbon and dealing with a multiplicity of joints, is also needed.

Summary of the Invention

This problem is solved in the instant invention which is a laminate article having at least two layers in which each of the layers comprises a plurality of units of unidirectional, parallel fibers embedded in a polymeric matrix, each of the units having a width of at least about 7.5 inches (about 191 millimeters), the fibers are essentially continuous within the at least two layers and the fibers have a fiber orientation angle of between 0° and 90° with respect to the longitudinal direction of the laminate article. A method to manufacture the inventive laminate article is also taught. Preferred fibers are extended chain polyethylene fibers and polyethylene naphthalate.

Other advantages of the present invention will be apparent from the following description, attached drawings, and attached claims.

Brief Description of the Drawings

Figure 1 illustrates a cross-plied laminate article of the invention and its hollow tube predecessor.

Figure 2 shows the spirally-wound hollow tube of Figure 1 hypothetically cut along a line parallel to the longitudinal axis of the tube relationships and opened flat to show a planar shape.

Figure 3 is a partial plan view of an article comprising a cross-plied laminate of the invention, with the layers partially removed to show the next adjacent layer.

Figure 4 illustrates a method useful in making the cross-plied laminate article of the invention.

Detailed Description of the Preferred Embodiments The term "essentially continuous" as used herein means fiber, yarn or cord which has a length greater than the length of the cross-plied laminate article of the invention and substantially greater than the width of the cross-plied laminate. Thus each strand of fiber reinforcement has only two cut ends in the entire length of the cross-plied article, and such cut ends are not located at the longitudinal edge of the inventive article.

Staple fiber is thus not part of this invention, per se, but is included to the extent that it forms part of a continuous spun yarn.

The term "fiber orientation angle" as used herein refers to the acute angle formed between the longitudinal axis of the unidirectional fiber and the longitudinal axis of the cross-plied laminate.

For the purposes of the present invention, fiber is an elongated body, the length dimension of which is much greater than the transverse dimensions of width and thickness. Accordingly, the term fiber includes monofilament, multifilament fiber, ribbon, strip, a plurality of any one of combinations thereof and the like having regular or irregular cross-section. The term fiber includes therefore twisted or untwisted yarns of a plurality of filaments and twisted or untwisted cords made from such yarns. Fiber also includes continuous spun yarns formed from staple fiber.

The term "unidirectional fibers" as used herein refers to the fibers used to reinforce the matrix material and how the fibers are arranged within the matrix. Unidirectional fibers are arranged in a substantial parallel fashion and thus are not crossed by other fibers within essentially the same layer of matrix material.

The term "ply" as used herein refers to a single layer in the laminate article of the invention. A ply may be continuous or non-continuous with any other ply in the inventive article. If the inventive article is made with a sheet of fiber-reinforced material helically wrapped singly around a mandrel roll, it will be a two-ply laminate and the two plies are continuous with each other. If the inventive article is made with two or more adjacent sheets of fiber-reinforced material helically wrapped in a single layer around a mandrel roll, it too will be a two-ply laminate, however the two plies are not necessarily continuous with each other. If the inventive article is made with more than one sheet wrapped in more than one layer around the mandrel roll, the resultant laminate will be four ply or more and some plies will not be continuous with other plies.

The term "cross-plied laminate" and "cross-plied article" as used herein refers to an article having two or more layers of fiber-reinforced material. In a two-ply cross-plied article of the invention, the longitudinal axes of fibers of the adjacent layers are rotated relative to one another. In a four-ply or more cross-plied article of the invention formed by wrapping more than one layer on the mandrel roll, only the two central adjacent layers have fiber longitudinal axes rotated relative to one another.

Depending on the application for use of the inventive laminate article different fibers and different matrices can be used, provided the composite layers used in manufacturing the laminate article are sufficiently deformable to bend around the mandrel roll and then be compacted into an essentially flat, at-least-two-layer cross-plied laminate article. Fibers for use in the practice of this invention may be metallic, semi- metallic, inorganic and/or organic. Useful fibers include polyolefin based polymers and particularly ultra high molecular weight polyolefin fibers including polyethylene and polypropylene fibers. Useful polyolefin fibers are taught in commonly-assigned U.S. Patents 4,413,1 10 and 5,578,374. Particularly useful starting fibers are AlliedSignal Spectra^® 900 and 1000 polyethylene fibers. Other useful fibers include: polypropylene fibers, polyester fibers, polyamide fibers including aramid fibers, polyvinyl alcohol (PV- OH) fiber, polyacrylonitrile (PAN) fiber, polybenzoxazole (PBZO) fiber, polγbenzothiazole (PBZT) fibers, fiberglass, ceramic fibers, carbon fibers, glass fibers, boron fibers, graphite fibers, asbestos, cellulose, alumina and metal fibers. Exemplary aramid fibers include poly(-phenylenediamine terephthalamide) fibers produced commercially by DuPont

Corporation of Wilmington, Delaware under the trade names of Kevlar® 29, Kevlar® 49 and Kevlar® 129. Exemplary PV-OH fibers as those, for example, by the process disclosed in commonly assigned U.S. Pat. No. 4,559,267 to Kwon et al. Detail on filaments of polybenzoxazoles (PBZO) and polybenzothiazoles (PBZT), may be found in "The Handbook of Fiber Science and Technology: Volume II, High Technology Fibers," Part D, edited by Menachem Lewin, hereby incorporated by reference.

Particularly useful units of a plurality of unidirectional fibers embedded in a polymeric matrix are taught in commonly-assigned U.S. Patents 4,403,012; 4,457,985; 4,623,574; 4,650,710; 4,748,064; 5,354,605; and 5,552,208.

The matrix material can comprise one or more thermosetting resins, or one or more thermoplastic resins, or a combination thereof. As used herein "thermoplastic resins" are resins which can be heated and softened, cooled and hardened limitless times without undergoing a basic alteration, and "thermosetting resins" are resins which do not tolerate thermal cycling and which cannot be resoftened and reworked after molding, extruding or casting and which attain new, irreversible properties when once set at a temperature which is critical to each resin. The key requirement of the matrix material is that it be flexible enough to process with the inventive method to generate the inventive laminate article. Choice of an appropriate matrix material would be obvious to one of ordinary skill in the art. Examples of useful matrix materials include a polyurethane matrix material available from Miles Inc. under the trade name DISPERCOLL U-42; a styrene-isoprene-styrene block copolymer available from Shell Chemical under the trade name Kraton^® D1 107; and tire rubber stock comprising natural rubber and styrene- butadiene rubber blends.

The fiber-reinforced composite which is used to form the laminate article of the invention is formed by conventional methods for embedding fibers in matrices or impregnating fibers with matrix material. The matrix material/fibers combination is then consolidated which means that the matrix material and the fiber are combined into a single unitary layer. Consolidation can occur via drying, cooling, pressure or a combination thereof. Fiber-reinforced rubber used in the formation of tire belts can be prepared as taught for instance in commonly-assigned, filed concurrently herewith pending application to Socci et al.

In materials used for ballistic resistant articles, consolidation is achieved substantially, if not completely, by drying. As described in commonly-assigned U. S. Patent 5,690,526, hereby incorporated by reference, for example, the fiber or yarn can be transported through a solution of the matrix material to substantially coat the fiber or yarn and then dried to form a coated fiber or yarn. The resulting coated fiber or yarn can then be arranged into the desired unidirectional network configuration to form a layer of ballistic resistant material. Alternatively, the fiber network can be constructed initially and then coated with the resin matrix material or embedded into a film of the resin matrix material.

The unidirectional fiber network can be constructed via a variety of well known methods. For use in ballistic resistant articles, for example, unidirectionaily-aligned fiber networks yarn bundles of high strength filaments, preferably having about 30 to about 2000 individual filaments of less than about 12 denier, and more preferably of about 100 individual filaments of less than about 7 denier, are supplied from a creel and led through guides and a spreader bar into a collimating bar prior to coating or impregnating with the matrix material. The collimating comb aligns the filaments coplanarly and in a substantially unidirectional fashion.

The unidirectional fiber network layers typically each contain from about 8 to 30 fiber ends per inch (EPI). For use in ballistic resistant articles, preferred is 8 to 12 EPI in each layer. For use in tire belt constructions, preferred is about 14 to 21 EPI in each layer.

The thickness of each fiber-reinforced composite can vary as necessary for a given end use, and of course, as long as the thickness does not preclude the helical winding and subsequent compaction into the inventive laminate. For use in ballistic resistant articles, each layer (including matrix material) is typically from about 0.01 mm to 0.2 mm, preferably about 0.04 mm to 0.12 mm, and most preferably about 0.06 mm to 0.10 mm thick. For use in tire belt constructions, each layer is typically from about 0.8 mm to 1.8 mm thick, preferably 1 mm to 1 .4 mm.

The fiber-reinforced composite used in the inventive laminate is typically a sheet having a length dimension considerably greater than its thickness, and greater than its width. The fibers therein are unidirectional and parallel to length (longitudinal) dimension of the sheet.

As shown in Figure 1 , the composite of the instant invention is effectively an endless cylindrical tube 19 of helically- or spirally-wound continuous, unidirectional fiber- reinforced material 21 which is then collapsed or flattened thus forming a two layer laminate 23 having two central layers 25 and 27 in which the fibers in the two layers are oriented in alternate directions (±) with respect to the longitudinal axis of the tube. The angle θ (the fiber orientation angle) is the acute angle formed by the displacement of the fiber reinforcement from the longitudinal axis of the composite. The immediately adjacent longitudinal edges of the spirally-wound material are abutted such that there are essentially no gaps and no overlaps in the tube. Because a single sheet is wrapped singly to form the tube 19 shown in Figure 1 , the resultant abutted joint 29 is essentially a single, spirally-wound joint which takes on a zigzag pattern when the tube is flattened to form the two layer laminate 23. Each ply 25 and 27 in the laminate 23 has a plurality of units 31 , consecutively arrayed in the longitudinal dimension of the laminate article. Each unit has butt joints with the two adjacent, coplanar units and each unit in one ply is the continuation of a unit in another ply.

As a consequence of the spiral wrapping, the reinforcement fibers are not cut along the edges parallel to the longitudinal direction of the composite. Indeed, the reinforcement fibers, parallel to abutted joint 29, are continuous throughout the length of the composite and are folded at the edges parallel to the longitudinal direction of the composite. Such continuous, uncut fiber reinforcement has been shown to dramatically increase the fatigue life of composites containing them, as well as increase tensile modulus and maximum load and reduce delamination of the composite, as shown utilizing novel polyethylene naphthalate cords and tire rubber in the concurrently-filed US patent application #09/288,589.

W,_8m, the resulting width of the flattened tube and thus of the laminate article, is equal to about one-half the circumference (C) of the originally-cylindrical tube as shown in the following equation:

W_lam = 0.5 x C (1 )

In order to achieve the exactly abutted edges of spirally-wound material, there is a discrete relationship between the circumference of the mandrel roll, the width of the fiber-reinforced material (W,) and the fiber orientation angle in the composite (θ) which is shown in the following equation:

W, = C x cos(θ) (2)

This relationship is illustrated in Figure 2 which shows a spirally-wound hollow tube 19 with abutted joint 29. Hypothetically cutting the tube 19 along a line parallel to the longitudinal axis of the tube 19 results in the planar shape 33 in which the relationship between W„ the width of the fiber-reinforced composite, C, the circumference of the mandrel roll and θ, the fiber orientation angle, is graphically illustrated.

The width W, in the above equation may be the width of a single sheet of fiber- reinforced material or can be the sum of widths of two or more sheets of fiber-reinforced material. Preferred is a single sheet. To minimize the frequency of abutting joints in the laminate, and to provide a usefully-wide, continuous length laminate from a single sheet of fiber-reinforced composite material, the width of any single sheet of the fiber- reinforced composite material is equal to or greater than about 7.5 inches (about 191 millimeters (mm)), more preferably equal to or greater than about 24 inches (about 610 mm) and most preferably equal to or greater than about 75 inches (about 1910 mm).

The fiber orientation angle θ can be between ± 0° and 90 °. When the fiber orientation angle is set at 45°, the resultant composite will have the unidirectional fibers in the immediately adjacent two center layers angled at right angles to each other. This angle is useful in ballistic resistant articles made from the inventive laminate. A fiber orientation angle of at least about 23° is useful for tire belt applications of the inventive laminate.

When one uses the minimum composite width of 7.5 inches and the largest allowable fiber orientation angle θ of about 89°, the resultant laminate will have no more than two abutted joints in any 12-inch length perpendicular to the width of the laminate,

W_lam.

A laminate of more than two layers can be made by several different methods. One can form the spirally-wound tube using two or more adjacent sheets of fiber- reinforced material and then flatten or collapse the multiple ply tube to form the four or more layers of the laminate. The fiber orientation angle of the two or more sheets may be the same or can be different. If different, the width of the two sheets will be different as dictated by equation (2). Alternately, one may stack two or more of the inventive laminates, having the same or different fiber orientation angles, to achieve four or more layers in a more highly laminated article. Alternately, one may stack the laminate with one or more layers of a sheet having unidirectional fiber parallel to the longitudinal direction of the sheet. Alternately, one may stack one or more inventive laminates with one or more of the product of the method in commonly-assigned U. S. Patent 5,173,138. For example if the inventive laminate has a fiber orientation angle of ± 45°, and the product of the method in U. S. Patent 5,173,138 has a 0 90° orientation, the resultant stack will have fiber reinforcement parallel to, perpendicular to and at ± 45° to the longitudinal axis of the stack. Figure 3 illustrates a portion of one such arrangement wherein the fiber orientation angle in plies 35 and 37 is respectively + 45° and - 45° and plies 39 and 41 are, respectively, perpendicular to and parallel to the longitudinal axis 43. Alternately, one may stack two or more of the laminates and one or more layers of a sheet having unidirectional fiber parallel to the longitudinal direction of the sheet, in any order desired, to achieve a composite having 5 or more layers of fiber-reinforced material.

The laminate can optionally be formed with a layer of, for instance, polyethylene film, simultaneously placed on the exterior of the spirally-wound tube thus generating a structure which can be further laminated with the film immediately after the tube is collapsed. Alternatively, the film can be supplied to both sides of the already-collapsed tube.

A method of forming the inventive laminate is as follows and as illustrated in Figure 4. Fiber-reinforced composite sheet 21 is provided continuously to a mandrel roll 45 (driven roll) in such a way that the longitudinal dimension of the sheet and thus the unidirectional fibers therein are neither perpendicular to the axis of the mandrel roll nor parallel to the axis of the mandrel roll and therefore are between 0° and 90° with respect to the axis of the mandrel roll. This angle is the fiber orientation angle θ. The composite sheet is also positioned such that adjacent edges are essentially abutting, no overlap, no gaps, so as to continuously envelop the mandrel roll and form abutted joint 29.

An alternate method of manufacture comprises forming the spirally-wound tube by configuring it along the inside of a hollow roll or a spirally-twisted track. This could be achieved for instance using a plurality of nip rolls to maintain the composite in the spiral configuration against the interior wall of such a hollow roll.

An alternate method of manufacture is folding the sheet as disclosed in concurrently-filed application of Socci et al. either manually or in an automated procedure. That application teaches a series of folding steps as schematically shown in Figure 5 which results in a laminate article having cross-plied fiber reinforcement. With reference to Figure 5a, a fiber-reinforced composite 79 is shown with fiber reinforcement 1 1 parallel to the longitudinal direction of the sheet. In Figure 5b, the composite 79 is folded to bring point 81 to point 83 by folding along line 85. The angle θ between the line 85 and the edge 87 is the resultant fiber orientation angle in the laminate. The once-folded composite is turned over as shown in Figure 5c and point 89 is brought to point 91 by folding along line 93 as shown in Figure 5d. The line 95 indicates W|_am. The twice-folded composite is turned over again as shown in Figure 5e and point 97 is brought to point 99 by folding along line 101 as shown in Figure 5f. The thrice-folded composite would be turned and folded continuously in the same manner to generate an indefinite length of the laminate article.

The thus-formed spirally-wrapped tube is advanced off the mandrel roll in a controlled fashion to maintain the abutted joint configuration, and provided to a device, such as nip rolls 47, which serve to collapse the tube to essentially eliminate the hollow core of the tube and form the laminate 23. The nip rolls may or may not be heated. The laminate article may be wound up to form a bolt 49. Alternately the laminate article may be cut into lengths useful for a given utility. If desired, the fold on the longitudinal edges of the laminate article may be eliminated after the article is formed by slitting the folds or trimming them off.

Keeping the abutted edges together may be accomplished in a variety of ways. For instance, they may be kept together by the controlled advancement of the spirally- wound tube through use of nip rolls positioned along the mandrel roll with axes of rotation perpendicular to the axis of the mandrel roll and nip rolls in the flattening device. These sets of nip rolls advance the tube at the same linear rate. In addition, or alternately, the use of adhesion or adhesive tape may be employed to assist in keeping abutted edges together. It is important, however, to keep in mind that the presence adhesive tape may hinder, for instance, the even application of pressure throughout the composite in subsequent further lamination processes. Alternately the mandrel roll could have a screw surface with the same helical configuration as the turning of the mandrel to take up the sheet, the screw surface serving to advance the spirally-wound sheet in a controlled fashion.

The laminate article of the invention is useful in a diverse multitude of articles. It is particularly useful in ballistic resistant articles. It is also useful in: components for passenger tires, sailcloth, and mailing packages.

EXAMPLES

Inventive Example 1

A two-layer laminate is made using a starting fiber and matrix material having a width of about 76.5 inches and an essentially endless length. The fiber is a 1300 denier/ 120 filament extended chain polyethylene yarn called Spectra^® 1000, commercially available from AlliedSignal, Inc. and there are 8 to 10 EPI in the starting material. The matrix is Kraton D1 107. The fiber orientation angle θ is 45°. The mandrel roll circumference is about 108 inches. The starting material is helically- wrapped around the mandrel roll and the resultant helical tube is advanced off the mandrel roll using nip rolls and is simultaneously and at the same linear speed pulled by heated nip rolls which serve to compact the helically-wound tube into the two-ply laminate of the invention, which is rolled up on a bolt. The resultant laminate has a width of about 54 inches. The fibers in one layer are oriented 90° with respect to the fibers in the adjacent layer, a configuration which is particularly useful in ballistic resistant articles. In both layers, the fibers are oriented 45° with respect to the longitudinal axis of the two-ply composite. The two-layer laminate has no cut fibers along its longitudinal edges but rather has folds; the fibers are continuous throuςhout the length of the laminate.

Inventive Example 2 Inventive Example 1 is repeated with the following changes: the starting material has an 89.5 inch width, the matrix material is DISPERCOLL U-42, and the mandrel roll circumference is about 1 26.6 inches. The resultant laminate has a width of about 63 inches.

Inventive Example 3

Inventive Example 1 is repeated except a polyethylene film is wrapped around the mandrel roll, simultaneous with the starting fiber and matrix material, and is provided such that it forms an outer layer on the helically-wrapped tube and thus comprises outer layers on the resultant compacted laminate article.

Inventive Examples 1 , 2 and 3 are used in constructing ballistic resistant articles.

Inventive Example 4

A two-layer laminate is made using a starting fiber and matrix material having a width of about 7.5 inches and an essentially endless length. The fiber is polyethylene naphthalate, commercially available from AlliedSignal, Inc. as PENTEX™ , in a 1000/2/3 cord having about 7 denier per filament. There are 21 EPI in the starting material and the polymeric matrix is commercially-used tire rubber. The fiber orientation angle θ is 23°. The mandrel roil circumference is about 8.1 inches. The starting material is helically-wrapped around the mandrel roll and the resultant helical tube is pushed off the mandrel roll using nip rolls and is simultaneously and at the same linear speed pulled by nip rolls which serve to compact the helically-wound tube into the two-ply laminate of the invention. The resultant laminate has a width of about 4 inches.

This laminate is used in a tire belt construction.

Inventive Example 5

Inventive Example 4 is repeated with the following changes: the PEN fiber is a 1300 denier/ 140 filament fiber, the starting material has a width of about 89.5 inches, the fiber orientation angle is 45°, the matrix is Kraton D1 107. and the mandrel roll has a circumference of 126.6 inches. The resultant laminate has a width of about 63 inches.

This laminate is used in a ballistic resistant article. It is anticipated that the use of polyester resin as the polymeric matrix material N fiber starting composite will be even more useful.

Claims

WHAT IS CLAIMED IS:

1 . A laminate article comprising: at least two layers, each of said layers comprising a plurality of units of unidirectional fibers with a polymeric matrix, each of said units having a width of at least about 7.5 inches (about 191 millimeters), said fibers being essentially continuous within said at least two layers, and said fibers having a fiber orientation angle θ between 0° and 90° with respect to the longitudinal axis of said composite article.

2. The laminate article of claim 1 wherein said fiber orientation angle is 45°.

3. The laminate article of claim 1 wherein said width of each of said units is at least about 24 inches (about 610 millimeters).

4. The laminate article of claim 1 wherein said fibers are polyethylene, polyamide or polyester.

5. The laminate article of claim 1 having at least four layers.

6. The article of claim 5 wherein said fiber orientation angle in two of said at least four layers is different from said fiber orientation angle in the remainder of said at least four layers.

7. The laminate article of claim 1 having a laminate width W,,_m described by the equation W_tam = WJ2cos(θ) wherein W, is the width of fiber-reinforced material.

8. The laminate article of claim 1 having a length of at least about 88 inches.

9. The laminate article of claim 1 further comprising a layer of film encasing said laminate article.

10. The laminate article of claim 1 wherein at least one longitudinal edge of the article is a fold.

1 1 . The laminate article of claim 10 wherein only one longitudinal edge of the article is a fold.

12. An article comprising the laminate article of claim 1 .

13. An article comprising two or more layers of the laminate article of claim 1 .

14. A ballistic resistant article comprising the laminate article of claim 1 .

15. A tire belt comprising the laminate article of claim 1 .

16. A ballistic resistant article comprising the laminate article of claim 2.

17. A method to make a laminate article comprising the steps of: forming continuously a hollow tube of spirally-wound fiber-reinforced composite material, collapsing said hollow tube in a controlled fashion to make an at least two-ply laminate article.

18. The method of claim 17 wherein said hollow tube is formed with butt joints between adjacent units of said spirally-wound fiber-reinforced composite.

19. The method of claim 18 wherein said butt joints occur no more frequently than twice in a twelve-inch length perpendicular to the width of said laminate article.

20. The method of claim 17 wherein said hollow tube is formed by wrapping said fiber- reinforced composite material around the outer surface of a roll.

21 . The method of claim 17 wherein said hollow tube is formed by wrapping said fiber- reinforced composite material against the inner surface of a roll.

22. The method of claim 17 wherein said collapsing step fashion utilizes nip rolls.

23. The method of claim 17 further comprising the step of laminating said at least two- ply laminate with a layer of film on at least one surface.