SYSTEMS AND METHODS FOR THE TRANSFER OF COLOR AND OTHER PHYSICAL PROPERTIES TO FIBERS, BRAIDS, LAMINATE COMPOSITE MATERIALS, AND OTHER ARTICLES

BACKGROUND OF THE INVENTION

This invention relates to providing a system and method relating to coloring individual fibers, braids and laminate materials generally.

In the textile fibers industry, the coloration of fibers is a requirement for a large number, if not a majority of military, commercial, apparel, industrial, medical and aerospace applications. However, laminated reinforced materials are plain in color and not conducive to being dyed or colored. One known technique for adding color to laminated material is to paint the material. However, painting the material has the downside of the paint flaking off through use and fading in sunlight over time. These drawbacks can be very pronounced in flexible laminate material. In another prior art embodiment, laminated reinforced materials are combined with additional layers of films or other materials to produce a fiber reinforced flexible fabric. The other additional materials may include a more traditional woven cloth that is capable of being dyed. Materials of this type are generally found in applications requiring high performance and visual or cosmetic appearance is secondary. The typical accepted appearance is plain, as manufactured, and/or lacking visual coloration, patterns, or graphics.

Ultra-high molecular weight polyethylene (UHMWPE) fibers have been traditionally available in one and only one color, namely translucent white. Such fibers are sold, for example, under the brand names Dyneema® and Spectra®. Limitation of UHMWPE fibers to only one shade of white has limited the suitability of UHMWPE fibers in many areas where it otherwise has applicability but cannot meet the requirements for an end use product that needs a color other than white to meet necessary product requirements or specifications.

Past attempts at dyeing or colorizing UHMWPE fibers, such as Dyneema® or Spectra® fiber, have been largely unsuccessful due to an inability to coat the fiber surface with a durable, colorfast finish resistant to abrasion, environmental exposure, washing, or chemical degradation. A lack of adhesion and/or colorfastness of dye or colorant is especially problematic in applications where the breakdown of the coloration and possible transfer to other surfaces or to the environment can cause contamination, discoloration or, in the case of medical applications, toxicity, infection or a breakdown of engineered surface properties such as surface tension, coefficient of friction, lubricity and wettability.

Attempts to add colorant into the polyethylene polymer precursor before spinning and drawing operations have also been unsuccessful primarily due to a unacceptable drop in mechanical properties of often greater than 50% due to chain scission and polymer degradation or interaction effects between the polymer and colorant, but also because of processing difficulties, supply chain issues and manufacturing complexity of having to support multiple colored variants of precursor polymers and cleaning and re-setup of equipment for runs and different colored fibers. Even with extensive down time for cleaning, it's very difficult to avoid cross contamination between different runs of varying colors of fibers.

Thus, it is desirable to produce colored fibers, braids and laminated reinforced materials that are colored or colorable, patterned, or enriched with other physical properties, such as resistance to fading.

SUMMARY OF THE INVENTION

In various embodiments of the present disclosure, dye sublimation coloring techniques are used for the coloration of UHMWPE materials. In various aspects, the UHMWPE material comprises any one of a fiber, a braid, and a laminate composite material. For example, the UHMWPE material colored per the methods herein may comprise drawn UHMWPE fibers made through gel spun technology, such as Dyneema® fibers. Coloration methods in accordance with the disclosure allow infusion of colorant into gel spun UHMWPE fibers themselves under controlled conditions of heat and pressure. In addition to being an effective method of fiber coloration, various embodiments of the dye sublimation coloration method herein can be implemented after the fibers are spun from the polymer solution, at many points in the fiber or braid manufacturing process, using a wide number of readily available coating or transfer methods in a wide range of colors. This processing flexibility enhances the utility, practicality and economic efficiency of the process while allowing the color to be applied at a point in the product stream that streamlines and simplifies inventory and process flow.

More importantly, while other coloration techniques can adversely reduce the mechanical properties of UHMWPE fibers by 50% or more, infusion of colorant into the fibers themselves via the dye sublimation method herein can be accomplished without significant changes to the mechanical properties of the fibers, such as Strength and Engineering Young's Modulus, both of which are critical for UHMWPE fibers and a primary selling point of the fibers.

In various embodiments of the present disclosure, UHMWPE fibers and braids were colored with two (2) or more colors, in multiple sections along each fiber or fiber braid, (a) without reducing the tensile strength of the fiber/braid by more than 10%; (b) without excessive colorant residue; and (c) using no surface coating (just colorant/dye). In various embodiments, the method comprises wrapping fibers around an expandable mandrel and allowing the mandrel to expand and tension the fibers during the coloration process.

In various aspects, a method of transferring a dye to a composite material comprises: applying the dye to a transfer media to create a colored transfer media; placing the colored transfer media into contact with the composite material; and applying, such as by using an autoclave, at least one of heat, external pressure, and vacuum pressure to infuse the dye to the composite material to create a colored composite material. The method may further comprise cooling the composite material to a temperature such that the composite material maintains a desired shape. In various aspects, the method may further comprise curing the dye, by applying at least one ultraviolet or electron beam radiation, to the composite material. Also, the method may further comprise adding a coating, (such as a polyimide), to the composite material. Additionally, the method may further comprise adding a polyvinyl fluoride (PVF) film to the composite material and/or nylon and/or urethane coating to the composite material. In various embodiments, a film is used as a color transfer medium remaining as a film coating on a composite material after the colorization process.

In various embodiments, the composite material comprises a non-woven material or a woven material. In various embodiments, the composite material comprises at least one layer of woven material and at least one layer of non-woven material. The transfer media may comprise at least one of transfer paper, transfer laminate, or transfer film. The dye may be applied to the transfer media in the shape of a pattern, graphic or logo, and wherein the composite material is infused with a matching pattern, graphic or logo, respectively. In addition, the dye may be applied to the transfer media using direct printing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary embodiment of a rotary color transfer system;

FIGS. 2A and 2B illustrate an exemplary embodiment of a heated press color transfer system and corresponding pressure graph;

FIG. 3 illustrates a flow chart of an exemplary heat press process;

FIGS. 4A and 4B illustrate an exemplary embodiment of an autoclave color transfer system and corresponding pressure graph;

FIG. 5 illustrates a flow chart of an exemplary autoclave process;

FIG. 6 illustrates an exemplary embodiment of a linear color transfer system;

FIG. 7 illustrates an exemplary embodiment of a multilayered color transfer stack;

FIG. 8 illustrates an embodiment of an expandable structure in accordance with the present disclosure;

FIG. 9 illustrates an embodiment of an autoclave cure schedule for fiber and braid specimens, plotted as temperature versus time for both the autoclave temperature (° F.) and the part temperature (° F.);

FIG. 10 illustrates an embodiment of an autoclave cure schedule for fiber and braid specimens, plotted as pressure/vacuum versus time for both the autoclave pressure (psi) and the vacuum (psi);

FIG. 11 illustrates Spectra® fiber braid tensile test results for as-received material;

FIG. 12 illustrates Spectra® fiber braid tensile test results for as-received material, in plotted form;

FIG. 13 illustrates Spectra® fiber 1740 dtex braid tensile test results on dyed material;

FIG. 14 illustrates Spectra® fiber 1740 dtex braid tensile test results on dyed material, in plotted form;

FIG. 15 illustrates a plot of Tenacity versus Tensile Strain for as-received Spectra® 1000, 400 denier fibers; and

FIG. 16 illustrates a plot of Tenacity versus Tensile Strain for dyed Spectra® 1000, 400 denier fibers.

DETAILED DESCRIPTION OF THE INVENTION

While exemplary embodiments are described herein in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that logical material, electrical, and mechanical changes may be made without departing from the spirit and scope of the invention. Thus, the following detailed description is presented for purposes of illustration only.

Materials

In various embodiments, fibers, braids, fabrics, and laminated materials are colored in accordance with the present disclosure. Various types of fibers and braids include, for example, Dyneema® or Spectra® brand UHMWPE materials. In various embodiments, UHMWPE fibers are colorized and modified by the methods according to the present disclosure. UHMWPE is a type of polyolefin made up of extremely long chains of polyethylene. Trade names include Dyneema® and Spectra®. UHMWPE is also referred to in the industry as either high-modulus polyethylene (HMPE) or high-performance polyethylene (HPPE). The molecular weight (MW) of UHMWPE is often expressed as “Intrinsic Viscosity” (IV), which is typically at least 4 dl/g and preferably at least 8 dl/g. Generally, the IV for UHMWPE is less than about 50 dl/g, and preferably less than about 40 dl/g. In various embodiments, the UHMWPE fibers comprise extruded polymer chains. In various embodiments, the UHMWPE fibers comprise pultruded polymer chains.

Various types of composite materials include both woven materials and non-woven materials. In an exemplary embodiment, woven materials comprise many low denier tows (i.e., light weight fibers). Woven materials comprise fibers passing over and under each other in a weave pattern that can result in some degree of crimp in the fibers. Also, in woven materials, tensile loading induces transverse loads at fiber overlap sections as crimped fibers attempt to straighten. The transverse loads reduce the translation of fiber strength to fabric strength, and decrease long-term fatigue and creep rupture performance. In an exemplary embodiment, higher performance engineering fibers have more pronounced crimp-related reduction properties. This is particularly pronounced in fibers with optimization of axial filament properties and reduced transverse properties of the filaments.

As used herein, a composite material is defined as one or more layers of unidirectional fiber and polymer matrix plies oriented in one or more directions. For example, unidirectional fibers in adjacent plies may be offset at an angle between their directions. In contrast, in an exemplary embodiment, non-woven composite materials use high denier tows for easier manufacturability. Non-woven composite materials, such as felts, comprise fibers that do not pass over and under each other and thus do not have crimp. An advantage of non-woven composite materials is unlimited fiber areal weights, which is the weight of fiber per unit area. In other words, thicker fibers can be used in non-woven materials versus woven materials. Another advantage of non-woven composites is the ability to form composite materials from multiple layers of fibers oriented at any angle relative to fibers in other layers. Furthermore, in an exemplary embodiment, a non-woven composite material is designed with optimal weight, thickness, and strength at particular locations or along predetermined load paths as desired. In addition, non-woven composite materials constructed from high modulus fibers can have predictable and linear properties for engineering designs.

In accordance with an exemplary embodiment, a composite material is infused with color during the manufacturing process. In various embodiments, the composite material comprises one or more layers of thinly spread high strength fibers such as, for example, UHMWPE, (commercially available as, e.g. Dyneema®), Vectran®; aramid; polyester; carbon fiber; Zylon PBO, or other materials, coated and/or embedded in a resin or other material, or any combination thereof. A particular preferred embodiment of the present invention relates to colorization of composite material comprising one or more layers of thinly spread high strength UHMWPE fibers.

In the context of the present invention, “high strength” means a tensile strength of at least 1.5 GPa; preferably 2.5 GPa; more preferably at least 3.6 GPa and most preferably at least 4.2 GPa. Fibers subject to colorization according to the methods disclosed herein may be characterized by various physical properties, in addition to characterization by particular chemical composition. These properties, for example, relate to stretch and strength of the fibers. Tensile properties (measured at 25° C.): tensile strength (or strength), tensile modulus (or modulus) and elongation at break (or EAB) are defined and determined on multifilament yarns as specified in ASTM D885M, using a nominal gauge length of the fiber of 500 mm, a crosshead speed of 50%/min. On the basis of the measured stress-strain curve, the modulus is determined as the gradient between about 0.3 and 1% strain. For calculation of the modulus and strength, the tensile forces measured are divided by the titre, as determined by weighing 10 meters of fiber; values in GPa are calculated assuming a density of 0.97 g/cm³.

Polymers such as used for fibers, generally have an “Intrinsic Viscosity” (IV) that can be determined according to ASTM D1601-2004 (at 135° C. in decalin), the dissolution time being 16 hours, with DBPC as anti-oxidant in an amount of 2 g/l solution, by extrapolating the viscosity as measured at different concentrations to zero concentration.

Linear polymers also may be characterized by the amount of side chains present. For example, the number of side chains in a UHMWPE sample is determined by FTIR on a 2 mm thick compression molded film, by quantifying the absorption of infrared radiation at a wavelength of 1375 cm⁻¹using a calibration curve based on NMR measurements (as e.g. disclosed in EP 0269151).

The infused color may appear as a solid color, a pattern, or any type of graphic such as a picture or logo on one or both sides of the composite material. Other possibilities include manufacturing the composite materials to have stripes, polka dots, figures, shapes, and the like. In an exemplary embodiment, the laminate films and/or fabrics can also have other tints sublimating or non-sublimating, color bases, modifiers or ultra-violet or color stabilizers pre-incorporated to interact with, synergize, or modify the color process.

A colorant usable for sublimation/diffusion in accordance with the present disclosure may comprise a dye or a pigment or combinations thereof. For example, sublimation dyes that find use herein typically range from the following class of dyes: Acid, Vat, Pigment, Disperse, Direct and Reactive Dyes. In various embodiments, Disperse and Direct Dyes are preferred. These dyes are prepared from the chemical class of organic systems that is known as azo, anthroquinone and phthalocyanine dye systems. In other aspects, color possibilities include pigments such as titanium dioxide, carbon black, phthalo blue, quinacridone red, organic yellow, phthalo green, dark yellow ocher, ercolano orange, venetian red, burnt umber, viridian green, ultramarine blue and pewter grey. In some embodiments of fiber, braid and composite coloring, Royal Blue, Aqua Blue, Black, Steelhead Grey, Process Yellow, Fire Red, Scarlet Red, Process Red, Rubine Red, Magenta, Navy Blue, Process Blue, and Kelly Green sublimation dyes are useful, and can be used singly or in various combinations for colored patterns. The terms “dye” and “pigment” are used interchangeably herein to refer generally to a colorant for the method.

In other various embodiments, composite materials can also have various coatings added to alter various surface properties of the material. The various coatings can be in addition to, or as alternative to, color dyes added to the material. In a first exemplary embodiment, a film coating is added to the material. The specific film coating can be used to increase or decrease the composite's tensile strength, toughness, chemical and dimensional stability, weld-ability, gas barrier properties, electrical properties, high temperature resistance, ultra-violet or infrared radiation performance, and/or reduce the coefficient of friction. In a second exemplary embodiment, a polyimide coating is added to the composite material. The polyimide coating can alter the electric and dielectric properties of the material. Furthermore, the polyimide coating may be configured to increase the stability of the material properties over a wide range of temperature. In a third exemplary embodiment, a film, such as polyvinyl fluoride (PVF) film (Tedlar®), is added to the composite material. Film such as PVF film facilitates added weather durability, long term durability, and environmental stability. Similarly, in a fourth exemplary embodiment, nylon and urethane coatings both increase toughness and are flexible, along with lower mechanical and permeability properties. In other aspects, a dye transfer medium comprises a dye coated film, which remains behind as a layer of the composite material after the colorization process.

In accordance with an exemplary embodiment, a composite material may be layered with woven coatings to create a composite material hybrid. The woven coatings can be incorporated to increase abrasion resistance. For example, a woven coating on a composite material may comprise a Nylon woven layer. Furthermore, in an exemplary embodiment, the composite material hybrid may be designed to combine the various material properties of the composite material and the coatings to result in a high strength, dimensionally stable flexible composite material. Exemplary applications of composite material hybrids include military applications, such as advanced visual camouflage and/or infrared signature reduction. Another example is use in a ballistic armor vest.

In an exemplary embodiment, sublimation infusion is implemented to achieve various additions to composite materials. The additions may include, for example, color, pattern, and gloss application, specular or infrared reflectivity modification, anti-microbial or medicines, surface adhesion modifiers, nano-material infusion, dielectric modifiers, the printing of conductive metal or polymer materials to add electrical/dielectric conductivity features or electrical circuit patterns, and/or incorporation of fire retardant materials or synergistic components for fire retardant materials in the laminate, surface films, or surface fabrics. In an exemplary embodiment, ultra-violet stabilizing or curing additives are incorporated into the material. These additives can extend the useful life of the composite material.

Furthermore, in various embodiments, a fire retardant adhesive or polymer is used with the composite materials. Furthermore, fire retardants may be added to a flammable matrix or membrane to improve the flame resistance of the composite material. Fire retardants may function in several ways, such as endothermic degradation, thermal shielding, dilution of gas phase or gas phase radical quenching. Examples of fire retardant additives include: DOW D.E.R. 593 Brominated Resin, Dow Corning 3 Fire Retardant Resin, and polyurethane resin with Antimony Trioxide (such as EMC-85/10A from PDM Neptec Ltd.), although other fire retardant additives may also be suitable as would be known to one skilled in the art. Additional examples of fire retardant additives that may be used to improve flame resistance include Fyrol FR-2, Fyrol HF-4, Fyrol PNX, Fyrol 6 and SaFRon 7700, although other additives may also be suitable as would be known to one skilled in the art. In various embodiments, fire retardancy and self-extinguishing features can also be added to the fibers either by using fire retardant fibers, ceramic or metallic wire filaments, inherent fire retardant fibers, or by coating the fibers. Examples of fire retardant fibers include Nomex® or Kevlar®. Inherent fire retardant fibers include fibers that have had fire retardant compounds added directly to the fiber formulation during the fiber manufacturing process. Furthermore, fibers may be coated with a sizing, polymer or adhesive incorporating fire retardant compounds, such as those described herein or other suitable compounds as would be known to one skilled in the art. In additional various embodiments, any woven or scrim materials used in the composite material may be either be pretreated for fire retardancy by the supplier or coated and infused with fire retardant compounds during the manufacturing process. In an exemplary embodiment, ultra-violet stabilizing or curing additives are incorporated into the composite material. These additives can extend the useful life of the material.

In various embodiments, the composite materials are assembled as a multilayer composite of outer surface layers, which may be colorized or textured, via any of the various application methods set forth herein. The outer surface layers may be unidirectional plies, films, non-woven fabric or felt, woven cloth, weldable thermoplastic membranes, waterproof breathable membranes and fabric scrims. These outer surface materials may have initial coloring or patterning complementary to the various methods of infusion transfer, sublimation transfer or roll transfer in order to obtain the desired cosmetic or visual effect. Additionally, in order to adjust the saturation, hue, opacity or light transmission of the finished colorized materials various powder tints, colored dyes or sublimation colorants can also be added to the bonding adhesives or the laminating resin component of the unidirectional ply layers. In order to further adjust the saturation, hue, opacity or light transmission of the finished colorized materials one or more tinted, opaque or light blocking film may be added between one or more laminate ply interfaces.

There are several applications suitable for the composite materials in industrial and technical textiles, apparel, sporting goods, water sports, boating and sailing materials, sail cloth, hunting and fishing, Balloon and Lighter Than Air vehicles, commercial fabric, upholstery, inflatable structure, military apparel, gear, medical or protective articles or devices, tension structures, seismic structural reinforcement materials, banner and signage and other flexible material or fabric applications where the high performance, light weight, high strength, rip and tear resistance, high flexibility, flex life, durability, weatherability and unique characteristics of flexible composite materials are very desirable but cosmetic or visual coloration, patterns, graphics and other visual properties or effects are also a significant component of the intended purpose of the material or product. Properties such as absorption or reflection of various wavelengths of the ultraviolet, visual, infrared or other regions of the electromagnetic spectrum and/or surface texture or shape, gloss or sheen, opaqueness, light transmission or blocking, or colorfastness and fade resistance are also desirable.

Since many of these potential applications are consumer oriented such as the apparel, outdoor, sporting goods, hunting and fishing, water sports, boating and sailing, or medical fabrics or textiles, which have special requirements or features such as fire retardancy or fire resistance, anti-odor, anti-mildew or anti-microbial resistance, water resistance and/or breathability, chemical resistance or abrasion resistance, any combination of the methods and materials are contemplated to fulfill the desirable characteristics for the intended application.

Methods of Application of Color

Various methods may be implemented to facilitate the transfer of dye to a composite material. These methods generally are of two types of processes: continuous process and batch process. A continuous process is one where material is unrolled at a steady web speed or at steady stepwise stop-and-start rate. The material is assembled, consolidated, colorized, textured and then rewound onto a rewind roll. In batch process, the composite material constituents and colorants are loaded into a press, vacuum bag or autoclave and then subjected to a heating/curing process.

In accordance with exemplary embodiments, the various methods of dye transfer may include heat transferring from a printed or saturated carrier; direct printing onto laminate or surface films via ink jet or dye sublimation printer; incorporation of dye, tint, or sublimating color or pattern directly onto or into the composite material or matrix; heat transfer onto a composite material or film; and bath or dipping infusion. In an exemplary embodiment, sublimating ink is used for more resistant and permanent coloring.

In accordance with an exemplary method, color is applied to a composite material using a transfer carrier substrate. As an initial step, the transfer carrier is selected, such as a film or paper. The color applied may be a solid color or may be a pattern or graphic, which is placed on the transfer carrier. The transfer carrier coloring process may use at least one of an inkjet printer, a gravure roll coater, a slot die coating head, dip bar bath coating, anilox roll coating, knife over roll coater, reverse roll coater, and an air knife coater. In various exemplary embodiments, application of a solid color to the composite material may be facilitated through direct printing or transfer onto an intended surface, layer, or interface of the laminated material with an autoclave, belt press, vacuum oven, and the like.

In various exemplary embodiments of direct printing, application of a pattern or graphic to the composite material may be facilitated through use of at least one of an inkjet printer, a sublimation printer, flexo printer process, anilox roll printing, and offset printing.

Whether a solid color or a pattern/graphic is transferred, the transfer carrier substrate is in proximity to the composite material, such that heat applied through various methods and systems if a separate carrier is used to transfer, infuse, or sublimate the color or pattern onto the composite material.

The various systems and processes applied to achieve the color transfer to composite materials include a heated rotary system, a heated press system, an autoclave system, a dye infusion system, a heated linear color transfer system, vacuum oven and matrix pigment tint coloring.

Heated Rotary System

In one exemplary embodiment and with reference to FIG. 1, a rotary color transfer system 100 comprises a rotating heated roll 110, a tensioned belt 120, a roll of material to receive color 130, and a color transfer carrier 140. Rotary color transfer system 100 is a continuous roll-to-roll process for applying color or graphics to materials 130. The material 130 that receives the color may be fabric, cloth, film, or laminated material. The film or fabric can then be used in the manufacture of composite materials. For example, rolls of finished composite materials, film or fabric precursor may be run through rotary color transfer system 100 to set or infuse the colors. In an exemplary embodiment, material 130 may be pre-coated or pre-printed with color before being fed through the belt press portion of rotary color transfer system 100.

In other embodiments, color transfer carrier 140 may be film or paper. The color transfer carrier 140 can be fed from rolls on an unwind and processed through rotary color transfer system 100 to transfer colors or patterns to material 130, such as film, fabrics, and composite materials. Accordingly, tensioned belt 120 is in contact with rotating heated roll 110. Furthermore, material 130 and color transfer carrier 140 are processed in contact with each other and rolled between rotating heating roll 110 and tensioned belt 120. The color can be applied to material 130 via direct printing either in-line or off-line. An in-line process includes applying or coating the colors or patterns to composite material, film or fabrics, or color carrier 140 as part of the belt press portion of rotary color transfer system 100. An off-line process includes applying or coating the colors or patterns to laminate, film or fabrics, or color carrier 140 as part of a separate batch process before being set up onto the belt press portion of rotary color transfer system 100. In an exemplary embodiment, heated rotary belt 120 can be used in-line with a lamination process. Moreover, the color can be transferred from color transfer carrier 140. In an exemplary embodiment, a vacuum is established between rotating heated roll 110 and tensioned belt 120 to facilitate color infusion and transfer. Various methods may be used to create the vacuum as would be known to one skilled in the art.

In an exemplary embodiment, and as illustrated in FIG. 1, color transfer carrier 140 is closest to rotating heated roll 110 and material 130 is closest to tensioned belt 120. In other exemplary embodiment, material 130 is closest to rotating heated roll 110 and color transfer carrier 140 is closest to tensioned belt 120. In an exemplary embodiment, material 130 and color transfer carrier 140 are both individual rolls that are unwound, processed through the rotary belt process as described above, and then rewound onto individual rolls.

Heated Press System

In accordance with an exemplary embodiment and with reference to FIGS. 2A and 2B, a heated press color transfer system 200 comprises two plates 210 or other similar hard surface, a material to receive the color 220, and a color carrier 230. In another embodiment, heated press color transfer system 200 further comprises a pressure intensifier layer 240 made from natural or synthetic rubber. By way of example, suitable caul rubbers are produced by Torr Technologies or Airtech International. The pressure intensifier layer 240 is coupled to the inside at least one of two plates 210 such that pressure intensifier layer 240 in between two plates 210 and in contact with composite material 220 and/or color carrier 230. In an exemplary embodiment, pressure intensifier layer 240 has at least some ability to compress. The compression facilitates additional pressure to be applied to two plates 210 and transferred to material 220 and color carrier 230. In various embodiments, pressure intensifier layer 240 may have a combination of one or more smooth mirror surfaces, smooth matte surface, and a textured or pattern surface to provide a desired surface gloss or texture that complements the colorants.

In an exemplary process and with reference to FIG. 3, a heat press process 300 includes four primary steps. First, apply a color tint/dye transfer to the color carrier, which may include composite material with a surface film or cloth surface on one or both sides, or may include transfer paper/film carrier (310). In various embodiments, the film or cloth surface may incorporate a complementary color or pre-printed pattern, image or design on one or both sides of the laminate. Furthermore, transfer paper/film carrier may contain solid color, one or more color patterns or printed graphics to form an image, design, or picture. Additionally, the transfer media may also include a smooth or textured surface to impart a surface with a desired degree of gloss or smoothness texture pattern on one or both sides of the colorized surface. Second, position the color tint/dye transfer in contact with the composite material (320). Third, apply heat and pressure to transfer, sublimate, and/or infuse the color, graphics, textures or patterns to the materials (330). Temperatures typically range from about 70° F. to about 650° F., and pressures range from the minimum to keep materials in intimate contact, typically 2 psi, to a maximum of 10,000 psi. The temperature and pressure applied depend on the particular colorant used, the substrates the colorant is applied to, and the degree of lamination or consolidation required. Fourth, cool the material to a temperature such that the finished article remains flat or in the desired shape, and such that there is no damage, distortion, or delamination of the finished colorized material. Once the system is at or below the removal temperature, the material and color carrier are removed from the heated press (340).

In yet another exemplary embodiment, the heated press color transfer system further comprises a vacuum to increase the pressure in the process. The exemplary vacuum may be created either by enclosing the press platens within a sealable vacuum chamber or by enclosing the laminate in a vacuum bag system. The applied vacuum can range from about 5 to about 29 inches of mercury (Hg). Once the vacuum has been applied, the assembly is placed into the press such that the press platens apply the appropriate pressure profile during the profile of the heating cycle and cooling cycle.

Implementing a vacuum is beneficial to assist in the sublimation colorant into the substrate, to lower the temperature at which sublimation colorant transfer occurs, to remove any trapped air or bubbles from the materials, and to prevent oxidization at higher temperatures. If appropriate, the material may be exposed to ultraviolet or electron beam radiation to cure or set curable tints or dyes.

Autoclave System

In accordance with an exemplary embodiment and with reference to FIGS. 4A and 4B, an autoclave color transfer system 400 comprises a rigid or reinforced elastomeric tool plate 410 and, optionally, a rigid or elastomeric caul plate 420 inside a vacuum bag 430. In various embodiments, tool plate 410 is typically a stiff plate having a smooth surface while caul plate 420 may be thinner and/or more compliant than tool plate 410. Vacuum bag 430 is made of flexible, impermeable material, or may be a flexible, impermeable elastomeric diaphragm. Alternatively, vacuum bag 430 may be sealed to the side or outer surface of first caul plate 410. Vacuum bag 430 is typically 0.001-0.015 inch thick nylon or other film that is sealed with a tape or strip of tacky high temperature caulk. Suitable bag and sealant materials include Airtech Securelon L500Y nylon vacuum bag and TMI Tacky Tape or Aerotech AT-200Y sealant tape. Moreover, if a diaphragm is used in place of a vacuum bag, the diaphragms are typically low durometer, high temperature resistant silicone rubber, and generally have a thickness of 0.032-0.060 inches.

In place of direct printing or color transferring to material, autoclave system 400 further comprises one or more color transfer carriers 440 and a colorant receiving material or laminate 450. Color transfer carrier 440 is placed in contact with receiving material 450, where both are between tool plate 410 and caul plate 420. For embodiments with high pressure and temperature operations or with large areas, a permeable felt or non-woven breather material may be included on top of the caul to allow air to flow freely under vacuum bag 430 in order to provide uniform compaction pressure. One example of a suitable breather material is Airtech Airweave 10. The air inside the vacuum bag 430 is removed via a vacuum tap 460, which creates a pressure differential in system 400 to provide compaction pressure on the part inside the vacuum bag 430. In exemplary embodiments, vacuum bag 430 may be placed inside a pressurized autoclave 470, such that the hyperbaric pressure inside autoclave 470, external to vacuum bag 430, is raised to a predetermined level. The predetermined level may be ambient atmospheric pressure up to 1000 psi to provide compaction force while the pressure under vacuum bag 430 is maintained at a vacuum of less than 2 to up to about 29 inch Hg.

In an exemplary embodiment, heat is more easily produced in a high-pressure environment and facilitates the transfer of dye to receiving material 450. The temperature inside the autoclave may be set to a predetermined heating rate profile, temperature hold and cool down profile. Typical temperature ramp rates vary from 2-50° F. per minute, to temperatures ranging from 70° F. to 600° F., with cool down rates ranging from 2-20° F. per minute. For the cooling profile, cool the material to a temperature such that the finished article remains flat or in the desired shape and such that there is no damage, distortion or delamination of the finished colorized material. Once the system is at or below the removal temperature, the material and color carrier are removed from the autoclave and removed from the bag. In an exemplary embodiment, autoclave color transfer system 400 is very effective and can be incorporated into a composite material manufacturing process.

In an exemplary process and with reference to FIG. 5, an autoclave process 500 comprises four primary steps:

(1) applying a color tint/dye transfer to the color carrier, which may include laminate with surface films or cloth surface on one or both sides, or transfer paper/film carrier (510). The film or cloth surface may incorporate a complementary color or preprinted pattern, image or design on either or both sides of the laminate. The transfer paper or media may contain a single color in an uninterrupted area, a single or multi-color pattern, or printed graphics of any color combination to form an image, design or picture. The transfer media may also include a smooth or textured surface to impart a surface with given degree of gloss, smoothness texture pattern on one or both sides of the colorized;

(2) placing the color tint/dye transfer in contact with the composite material (520);

(3) applying heat and pressure, and vacuum to transfer and/or infuse or sublimate the color, graphics, textures, or patterns to the materials (530). Temperatures typically range from about 70° F. to about 650° F., and pressures range from the minimum to keep materials in intimate contact, typically ambient atmospheric pressure to a maximum of 1000 psi. The temperature and pressure applied depend on the particular colorant used, the substrates the colorant is applied to, and the degree of lamination or consolidation required; and

(4) cooling the material to a temperature such that the finished article remains flat or in the desired shape, and such that there is no damage, distortion, or delamination of the finished colorized material. Once the system is at or below the removal temperature, the material and color carrier are removed from the vacuum bag tool assembly (540). In various appropriate embodiments, the material may be exposed to ultraviolet or electron beam radiation to cure or set curable tints or dyes.

Linear Color Transfer System

In one exemplary embodiment and with reference to FIG. 6, a linear color transfer system 600 comprises a rotating horizontal belt press 610, a film or membrane 620, and color transfer carrier 630. The endless rotating belts form a continuous process capable of applying a uniform, continuous consolidation pressure to a Composite Material 650, and color transfer film or paper carrier 630 to maintain intimate contact for infusion or sublimation color transfer. The materials are heated to a sufficient temperature to perform the color infusion in the pressurized heating zone and then cooling the composite material and color transfer media to a temperature that is at or below the safe removal temperature for the composite material. The linear color transfer system 600 may be a continuous roll-to-roll process for applying color or graphics to composite material 650. The composite material 650 that receives the color may be fabric, cloth, film, or laminated material. The film or fabric 620 can then be used in the manufacture of composite materials. For example, a web of assembled layers of rolls of finished Composite Material, film or fabric 620 precursors may be run through linear color transfer system 600 to set or infuse the colors. In an exemplary embodiment, material 650 may be pre-coated or pre-printed with color before being fed through the belt press portion 610 of the linear color transfer system by means of printer, coater or treater 660.

The colorized composite material may then be optionally run through a set of calendar or embossing rolls 670 to apply a smooth shiny or matt surface to the composite material or to apply a texture to one or both outer surfaces. The optional rolls 670 may be heated, chilled, or left at room temperature, depending upon the desired surface finish, surface texture, the exit temperature of the composite material from the belt portion of the press or the specific materials. Typical running speed for the composite material web ranges from 2-250 feet per minute. The rolls 670 and belt sections of the press 610 can be set either for a predetermined gap or a for a preset pressure to the preset roll gaps or with the gaps set to zero with a preset pressure to ensure full consolidation with a given pressure distribution. Typical gap settings range from 0.0002″ up to 0.125″ and typical pressures range from 5 to 1000 lbf per linear inch of width. The rolls and belt system can be heated to consolidate the materials and/or transfer, infuse or sublimate into one or both sides of the composite material. Individual plies of the composite may be unwound from a roll, laid up on the composite web by hand layup, by automated tape layup or by an automated robotic pick and place operation. Typical heating temperature set points range from 70° F. to 550° F.

Furthermore, typical heating temperature set points range from 70° F. to 550° F.

Radiation curing systems such as an E-beam or UV lamp array can be located in-line. One advantage of the linear system is that it can integrate the assembly of unidirectional fiber ply layers into a structural reinforcement, the application of the colorant, the incorporation of the various arbitrary internal or surface film layers, non-woven cloth layers and woven layers into a multi-step integrated manufacturing process where base unidirectional fiber plies are converted to finished, colorized roll goods.

Multilayer Composite Material Color Infusion

In an exemplary embodiment, multilayer composite material color infusion can be performed using either a heated press color transfer system, such as system 200 or an autoclave color transfer system, such as system 400. In either process and with reference to FIG. 7, a multilayered stack comprising multiple caul plates 710, barrier/breather layers 720, color carriers 730 and laminates 740 may be substituted for the single stack of composite material and color carrier described in system 200 and system 400.

Batch Dye Infusion

In an exemplary embodiment, composite material, surface films and surface fabrics can also have colors incorporated via batch dying or infusion. In this process, rolls of composite material, film or fabrics are saturated with color media or tint and placed in a vessel and exposed to an appropriate heat, pressure or vacuum profile to apply to infuse color media. The films or fabrics treated in this manner may then be incorporated into laminates.

Matrix Pigment and Tint Coloring

In an alternative to dye sublimation/diffusion into fibers and braids, pigment may be added to the adhesive resin used in the unidirectional fiber ply manufacturing process, thereby resulting in a color infused unidirectional tape subsequently used in the manufacture of the composite material. For example, materials that can be added directly into the adhesive resin include, but are not limited to, titanium dioxide, carbon black, phthalo blue, quinacridone red, organic yellow, phthalo green, dark yellow orcher, ercolano orange, venetian red, burnt umber, viridian green, ultramarine blue and pewter grey. In an exemplary embodiment the colored composite material that results from the use of the colored unidirectional fiber plies may be additionally colored using the before-mentioned processes, namely Heated Rotary System 100, Heated Press System 200/300, Autoclave System 400/500, Linear System 600, Multilayer Laminate Color Infusion 700, and/or Batch Dye Infusion.

Fiber and Braid Coloring Under Tensioning Conditions—General Considerations

In various embodiments, fibers or braids are under tension during colorization. Tensioning during colorization is believed to draw the fibers to some extent, counteracting the shrinkage of the fibers and negating the added weight of the colorant added per linear length of fiber. Not wishing to be bound by any particular theory, it is believed that controlling the inherent shrinking of fibers by tensioning during heating minimizes disturbances of the extended polymer chains in the fibers. Tensioning may be held relatively constant during colorization, or tensioning may vary (increasing or decreasing) during colorization. Also, pre-tensioned fibers, when subsequently exposed to heat during colorization, may relax to some extent, meaning the tension of fibers during colorization may be less than the pre-tensioning applied prior to colorization.

In one variation, fibers or braids are wrapped around an adjustable rig and pre-tensioned to a desired tension (i.e. force) prior to the start of the colorization process. Such an expandable structure may comprise an expandable tubular construct such as an expansion cylinder having circumferentially arranged segments that are driven apart from one another by the action of, for example, a bolt having a larger diameter than the inside diameter (ID) of the unexpanded segments. Such rigs are sometimes referred to as “expansion clamps for ID holding.” More elaborate variations of the rig can include a ratcheting mechanism that pushes paired elements (such as rods) in opposite directions, increasing the distance between the pair, and thus increasing the tension on the fibers or braids wrapped around them. Pre-tensioning of fibers or braids can be to any level of tensioning that is numerically less than the breaking point of the fiber or braid. That is, fibers or braids may be pre-tensioned to a percentage (<100%) of their break strength. For example, for colorizing UHMWPE fibers having a tensile strength of about 3.6 GPa, a pre-tensioning of the fibers at 20° C. to 1-30% of their break strength would equate to pre-tensioning the fibers prior to colorization to a force of 36 MPa to about 0.36 GPa. In various embodiments, fibers are pre-tensioned around a suitable rig at 20° C. to a force equal to 1-30% of the break strength of the fibers. In other embodiments, fibers are pre-tensioned at 20° C. to a force equal to 2-20% of the break strength of the fibers. In other embodiments, fibers are pre-tensioned at 20° C. to a force equal to 3-10% of the break strength of the fibers. Dye transfer paper may be placed on the rig prior to winding of the fibers over the paper and prior to the pre-tensioning by the expansion bolt or ratcheting mechanism. In various embodiments, another layer of dye transfer paper is placed over the pre-tensioned fibers. Then the assembled rig with the one or more dye transfer papers on either or both sides of the wound and pre-tensioned fibers is heated to sublime and diffuse the colorant from the transfer paper(s) into the fibers. In other embodiments, fibers are pre-tensioned on a tensioning rig and then the rig is simply submerged in a heated vessel of dye until the tensioned fibers are colored.

In another variation, fibers or braids are wrapped around a structure that expands during the colorization process, in which case the tensioning of the fibers or braids increases from little to no tension at the start of the colorization process up to a desired tension during the colorization process. Such a structure may expand at a measureable and predictable rate when heated at least about 10° C. above ambient. For example, the diameter of an aluminum tube or mandrel expands at a known rate when heated based on the known coefficient of thermal expansion (CTE) of aluminum. The gradual increase in diameter of for example an aluminum tube causes an increase in the tensioning of fibers wrapped around the tube when the tube is heated to an increase in temperature of at least 10° C. during colorization of the fibers.

UHMWPE fibers, such as Dyneema® fibers, have a negative CTE. That is, these types of fibers shrink when heated. The CTE of UHMWPE fibers is about −12×10⁻⁶/K. Given this known contraction, it is preferred that an expanding structure, such as a metal tube, be chosen to have approximately the opposite CTE of the fibers, such that the expanding structure counteracts or negates the contraction of the fibers during the colorization process when at least a 10° C. temperature increase occurs. Aluminum, for example, has a CTE of 22.2×10⁻⁶/K, and thus can be seen to be of the order of magnitude necessary to offset the shrinkage of UHMWPE fibers during the same heating. The CTE of copper is 16.6×10⁻⁶/K, pure iron 12.0×10⁻⁶/K and cast iron 10.4×10⁻⁶/K, and therefore structures, such as tubes, made from these metals are expected to tension UHMWPE fibers during the colorization process wherein at least a 10° C. increase in temperature occurs.

In various embodiments, the expandable structure comprises a tube made from a material having a CTE of from about 5×10⁻⁶/K to about 30×10⁻⁶/K. In various embodiments, the expandable structure is a tube made of glass, metal, granite, concrete or quartz. In various embodiments, the metal is chosen from the group consisting of aluminum, copper, pure iron, cast iron, silver, lead, nickel, palladium, and stainless steel. In various embodiments, the expandable structure is a glass, metal, granite, concrete or quartz tube having an ID approximately 20 times the wall thickness. The length of the tube is chosen primarily on the basis of practicality, such as the size of the autoclave or other system to be used for applying at least one of heat, pressure, force and vacuum, the scale of the colorization process (e.g. how many meters of fiber to be colored), the width of composite material to be colored, cost of a tube, and the like.

For the indirect coating of tensioned fibers, dye sublimation colorant saturated commercial transfer papers with solid and patterned colors may be used as the dye transfer medium. Although these transfer papers are suitable for smaller-scale processes, for production applications, the dye sublimation colorant could be applied directly to the tooling mandrels or process equipment via a wide range of coating methods such as gravure coating.

In various embodiments, a method of transferring a dye to a fiber, braid or composite material comprises: a) wrapping said fiber, braid or composite material onto an expandable structure; b) applying the dye to a transfer media to create a colored transfer media; c) placing the colored transfer media into contact with the fiber, braid or composite material; and, d) applying at least one of heat, external force, external pressure and vacuum pressure to infuse the dye to the a fiber, braid or composite material to create a colored a fiber, braid or composite material. Temperatures for this process typically range from about 70° F. to about 650° F., and pressures range from the minimum to keep materials in intimate contact, typically ambient atmospheric pressure to a maximum of 1000 psi. In preferred embodiments, the temperature of the colorization process is close to, but below, the melting point of the fibers. In various embodiments, the colored transfer media is a dye transfer paper with dye on one side. In other embodiments, an autoclave can be used in conjunction with the application of heat, force, pressure, and/or vacuum. In various embodiments, the expandable structure comprises an adjustable rig that can be expanded at 20° C. to pre-tension the fibers at preferably 1-30%, more preferably 2-20% or most preferably 3-10% of the breaking strength of the fibers prior to colorization. In other embodiments, the expandable structure is a tube, e.g. glass, metal, granite, concrete or quartz, which gradually expands when temperature is increased at least 10° C. to tension the fibers during the colorization process and offset the shrinkage of the fibers that would have occurred from the heating.

In various embodiments, a method of transferring a dye to a fiber, braid or composite material comprises: a) applying the dye to a transfer media to create a dye transfer media; b) wrapping the dye transfer media onto an expandable structure leaving the dye coated side of the dye transfer media exposed; c) wrapping said fiber, braid or composite material onto the expandable structure over the top of and in contact with the dye transfer media; and d) applying at least one of heat, external force, external pressure and vacuum pressure to infuse the dye to the a fiber, braid or composite material to create a colored a fiber, braid or composite material. In various embodiments, the colored transfer media is a dye transfer paper with dye on one side. In various embodiments, an autoclave can be used in conjunction with the application of heat, pressure, and/or vacuum. In various embodiments, the material to be dyed can be directly wound against the expandable structure, (e.g. winding fiber around a metal tube or expandable rig), or alternatively the dye transfer media can be wrapped against the expandable structure, and then fiber, braid or composite wrapped around the dye transfer media such that the dye transfer media is between the expandable structure and the fiber, braid or composite to be dyed. Temperatures for this process typically range from about 70° F. to about 650° F., and pressures range from the minimum to keep materials in intimate contact, typically ambient atmospheric pressure to a maximum of 1000 psi. In preferred embodiments, the temperature of the colorization process is close to the melting point of the fibers. In various embodiments, the expandable structure comprises an adjustable rig that can be expanded at 20° C. to pre-tension the fibers at preferably 1-30%, more preferably 2-20% or most preferably 3-10% of the breaking strength of the fibers prior to colorization. In other embodiments, the expandable structure is a tube, e.g. a metal tube such as aluminum, copper, pure iron or cast iron, which gradually expands when heated to tension the fibers during the colorization process and offset the shrinkage of the fibers that would have occurred from the heating.

In various embodiments, a method of transferring a dye to a fiber, braid or composite material comprises: a) applying the dye to a transfer media to create a dye transfer media; b) wrapping the dye transfer media onto an expandable structure; c) wrapping said fiber, braid or composite material onto the expandable structure over the top of and in contact with the dye transfer media; d) wrapping additional dye transfer media over said fiber, braid or composite material with the dye coated side in contact with the fiber, braid or composite, and e) applying at least one of heat, external force, external pressure and vacuum pressure to infuse the dye to the fiber, braid or composite material to create a colored fiber, braid or composite material. In other words, two layers of dye transfer media may be used to sandwich the fiber, braid or composite material to be dyed, all of which is wound around an expandable structure in layers. Temperatures for this process typically range from about 70° F. to about 650° F., and pressures range from the minimum to keep materials in intimate contact, typically ambient atmospheric pressure to a maximum of 1000 psi. In preferred embodiments, the temperature of the colorization process is close to, but below, the melting point of the fibers. In various embodiments, the expandable structure comprises an adjustable rig that can be expanded at 20° C. to pre-tension the fibers at preferably 1-30%, more preferably 2-20% or most preferably 3-10% of the breaking strength of the fibers prior to colorization. In other embodiments, the expandable structure is a glass, metal, granite, concrete or quartz tube, (e.g. a metal like aluminum, copper, pure iron or cast iron), which gradually expands when increased in temperature at least 10° C. to tension the fibers during the colorization process and offset the shrinkage of the fibers that would have occurred from the heating.

Exemplary Procedure for Colorization of Fibers Under Tension

In the example, tension is provided by the differential (and opposite) thermal expansion between the fibers and the expandable structure as they are both heated up together. Metal is typically the material of construction for expandable structures suitable for use in accordance with the present method, with a metal tube being ideally preferred. In various embodiments, the expandable structure comprises a metal tube having any wall thickness, diameter and length. In various embodiments, the metal tube comprises aluminum, copper, pure iron or cast iron. In various embodiments, the expandable structure comprises an aluminum tube having an ID about 20 times the wall thickness. In various embodiments, the expandable structure comprises a 10 inch ID aluminum tube having 0.5 inch wall thickness.

FIG. 8 depicts the expandable structure used in this example. Tubing 890 is an aluminum mandrel having 0.5 inch wall thickness and 10 inch ID. The fibers used in this example were Spectra® UHMWPE fibers. As mentioned, UHMWPE fibers have a negative coefficient of thermal expansion (CTE), which causes the fibers to contract as they are heated up, while the aluminum mandrel 890 has a positive CTE, which causes the mandrel to expand as it is heated. The combined action of the Spectra® fiber's contraction and the aluminum mandrel's expansion helps prevent loss of mechanical properties in the fibers caused by disturbances of the extended polymer chain configuration in the fibers.

Before application of the dye sublimation transfer paper to the surface of the aluminum mandrel, the mandrel was cleaned by scrubbing the surface with a solvent wipe saturated with methyl ethyl ketone (MEK) or other solvent to remove any oils or contaminants. The MEK was subsequently flashed off using a hand held heated air gun, and dye sublimation transfer paper was tightly wound around the outer surface of the mandrel with the dye sublimation side pointing outwards in order to be used as the contact surface with the fiber and braid being colorized. Both solid color and patterned dye sublimation transfer paper were utilized for this study with the solid pattern being used when a solid color is to be transferred to the fiber or braid and with the patterned transfer paper used when a multi-color sectioned pattern of colors is to be applied along the length of the fiber or braid. The transfer paper was secured to the mandrel with tape.

Once the transfer paper was secured to the mandrel the mandrel was mounted to a tension controlled winder using an inflatable core chuck and the fiber or braid spool was mounted on tension controlled let off. The Spectra® braid or fiber was then wrapped over the dye-sub paper at a predetermined tension such that each wrap of the braid was tightly wound in intimate contact with the coloration surface of the transfer paper and abutting but preferably not overlapping the adjoining wrap of braid or fiber. After the Spectra® braid or fiber was completely wound onto the mandrel a second sheet of dye sublimation transfer paper was overwrapped onto the fiber or braid layer, with the dye sublimation transfer surface pointing inwards, such that the dye transfer surface was in intimate contact with the outer surface of the Spectra® fiber or braid and the paper was secured with tape to prevent shifting of the transfer paper on the mandrel. In this way the fiber or braid layer is sandwiched between dye transfer paper layers, with each of the dye transfer paper layers arranged such that the dye side faces against the fiber or braid to be colored.

The outer layer of the transfer paper on the mandrel was covered with a layer of non-porous 2 mil thick Teflon® film to prevent migration of the colorant gases away from the Spectra® fiber or braid during the sublimation process. Also, a layer of Airweave N-10 was applied as a breather layer. The mandrel was then covered with a layer of Airtech 5 mil nylon vacuum bag sealed to the caul with Airtech tacky tape. An Airtech vacuum tap was inserted under the nylon film vacuum bag. The vacuum tap was locked in place to seal it against the nylon bag film and a vacuum hose connected to a high volume vacuum pump evacuate the air from under the vacuum bag.

A vacuum of 27 inches Hg was applied to the bagged assembly using a liquid ring vacuum pump in order to check for leaks in bag or sealing system.

The completed mandrel assembly was maintained under vacuum and placed into an autoclave. Once in the autoclave the vacuum tap on the mandrel was connected to the autoclave's internal vacuum system. The autoclave was pressurized to 5 psi with dry nitrogen to keep the bag from shifting, and the under bag vacuum on the mandrel was vented to the atmosphere to maintain atmospheric pressure on the sublimation paper during the autoclave heating process to prevent premature sublimation of the dye sublimation colorant before the Spectra® fiber had reached a sufficiently high temperature to allow the colorant to be infused into the Spectra® fiber filaments. This temperature was close to, but below, the melting point of the fibers, between about 275 and 280° F.

The autoclave temperature was ramped up to the sublimation transfer temperature of 275-280° F. and held at that temperature until the lagging tool and Spectra® fiber layer reached the transfer temperature. When the Spectra® material reached the transfer temperature the pressure of the autoclave was released to prevent damage to the Spectra® filaments while a vacuum of 28 in Hg was pulled under the vacuum bag to initiate the sublimation of the colorant off of the dye transfer paper and facilitate the colorant's infusion into the Spectra® fiber filaments. The Spectra® fibers were held at the 275-280° F. infusion temperature under vacuum for 15 minutes to allow the colorant to infuse into the Spectra® material. At the end of the 15 minute dwell period, the autoclave was cooled down to 150° F. while full vacuum was held under the mandrel vacuum bag.

TABLE 1

Autoclave cure schedule for fiber and braid specimens.

Time
Autoclave
Part
Autoclave
Vacuum

(hours)
Temp (° F.)
Temp (° F.)
Pressure (psi)
(inHg)

0
71
73
0
28

0.5
208
146
5
0

1
257
225
5
0

1.08
275
243
5
0

1.75
279
275
0
28

2
278
275
0
28

2.25
150
150
0
28

FIGS. 9 and 10 are plots of the data from TABLE 1. FIGS. 9 and 10 provide the autoclave dye sublimation infusion time, temperature, autoclave pressure, and mandrel under bag pressure schedule for the coloration cycle.

At the end of the infusion cycle, the mandrel assembly was removed from the autoclave, and the vacuum bag, breather cloth, Teflon® film and outer layer of transfer paper were each removed from the aluminum mandrel. The resulting colorized Spectra® fiber or braid was inspected for quality and uniformity of the colorization.

The mandrel was re-mounted onto the tension-controlled winder using an inflatable core chuck, and the fiber or braid was re-spooled onto a suitable core. The colorized fibers and braid were then subjected to tensile testing in a suitably equipped testing lab.

For the testing, an Instron 5667 Universal Test load frame controlled by Instron's Blue Hill mechanical test control and data collection system was used. A 500 Newton Instron load cell was mounted onto the load frame along with a set of Instron pneumatic grip fixtures optimized for the testing of Spectra® fibers and the grip length for the test fixtures was set to 250 mm. The colorized Spectra® fiber and braid were tested to failure at crosshead speed of 127 mm/min, with the load and displacement data collected for each sample test for calculation of tenacity and modulus. The test results for the colorized Spectra® braid and fiber were compared to un-colorized (i.e. “as-received”) Spectra® fiber and braid using the identical test set up and parameters. The test results for the colorized and un-colorized Spectra® fiber and braid were compared to evaluate the impact of the colorization process on tenacity and modulus.

FIG. 11 is a tabular summary of the test results on the Spectra® material in an “as-received” state, (i.e., prior to the colorization process). FIG. 12 is a plot of tenacity versus tensile strain for the un-colorized Spectra® material.

In comparison, FIG. 13 is a tabular summary of the test results on the colorized Spectra® material obtained from the process described immediately above. FIG. 14 is a plot of tenacity versus tensile strain for the colorized Spectra® material from the colorization process above. The material used was Spectra® fiber 1740 dtex braid.

Results

The averagelure load of the Royal Blue colored 1740 dtex braid was measured at 89.1 lbs., which gives a corresponding average strength of 22.78 cN/dtex. The average failure load of “as-received,” in the white grey goods uncolored 1740 dtex braid was 90.9 lbs., which gives a corresponding average strength of 23.24 cN/dtex. Compare FIG. 11 versus FIG. 13 to compare test results in tabular form, and compare FIG. 12 to FIG. 14 to compare Tenacity versus Strain plots of the colored and uncolored 1740 dtex braid samples. Recalculation of the percentage strength difference drops to reduction in tensile strength for the colored braid to 1.1% when the outlier in the test data is excluded.

From the test results, it was determined that the tenacity of the colored 1740 dtex Spectra® braid is 1.9% lower than the average tenacity of the uncolored material, (i.e. the white Spectra® 1740 dtex braid as tested directly off the factory roll). Inspection of the tabular data for failure strength of the colored braid showed an outlier in the data on Test #5 due to gripping error that resulted in a premature failure of the test sample. If the one outlier of Test #5 in the colored test sample is excluded from the data set, then the average failure strength for the colored samples increases to 89.8 lbs., and the average strength increases to 22.95 cN/dtex. Recalculation of the percentage strength difference drops to reduction in tensile strength for the colored braid to 1.1% when the outlier in the test data is excluded.

The average modulus of the colored 1740 dtex braid is 126.67 cN/dtex, which is actually slightly higher by 1.2% than the average modulus for the uncolored, in the white 1740 dtex braid, which tested at 125.07 cN/dtex. Although not wishing to be bound by any particular theory, this improvement in the modulus for the colored braid is believed to be attributed to some degree to heat setting and fiber alignment of the braid under tension induced during coloration heat and pressure cycle. Examination of the Tenacity vs Strain plots of the tensile test results in FIGS. 12 and 14 tend to support the improvement of tensile stretch propertied as a result of heat setting hypothesis.

As can be seen from the plots, the colored braids have a tighter, more reproducible load/displacement relationship, most likely due to the heat setting of the braid. TABLE 2 summarizes the average strength and average modulus for the Spectra® fiber braid “as received” and Spectra® fiber braid dyed, in accordance to the process herein.

TABLE 2

Average Strength and Average Modulus

Avg
Avg

Strength
Modulus

(cN/dtex)
(cN/dtex)

As-received Fiber Braid
23.24
125

Dyed Fiber Braid
22.78
127

Difference
−1.9%
+1.2%

Spectra® 1000, 400 Denier Fiber Test Results and Comparison

The average failure load of the Royal Blue colored Spectra® 1000 400 denier (425 dtex) fiber was 28.23 lbs., which gives a corresponding average tenacity of 29.51 cN/dtex. The average failure load of as-received, in the white uncolored 400 denier (425 dtex) Spectra® 1000 fiber is 29.94 lbs., which gives a corresponding average strength of 31.29 cN/dtex. TABLE 3 sets out these test results in tabular form.

TABLE 3

Average strength and average modulus for 400 denier fiber

Avg
Avg

Strength
Modulus

(cN/dtex)
(cN/dtex)

As-received Spectra ® Fiber 400 denier
29.94
1098

Dyed Spectra ® Fiber 400 denier
29.51
1115

Difference
−1.5%
1.5%

FIGS. 15 and 16 are Tenacity versus Strain plots of the uncolored (FIG. 15) and colored (FIG. 16) 400 denier (425 dtex) Spectra® 1000 fiber samples.

The test results show that the Tenacity of the colored 400 denier (425 dtex) Spectra® 1000 fiber is 1.5% lower than the average Tenacity of the uncolored, in the white 400 denier (425 dtex) Spectra® 1000 fiber as tested directly off the factory roll.

The average modulus of the colored 400 denier (425 dtex) Spectra® 1000 fiber is 1098.04 cN/dtex, which is slightly lower by 1.5% than the average modulus for the uncolored, in the white 400 denier (425 dtex) Spectra® 1000 fiber, which tested at 1115.07 cN/dtex. Although not wishing to be bound by any particular theory, this drop in the modulus for the colored braid is believed to be attributed to some degree due to the disruption of the catenary pattern in the fibers that drops the measured modulus due to non-uniformity of filament engagement. Examination of the scatter in Tenacity Vs Strain plots of the tensile test results in FIGS. 15 and 16 tend to support the notion that the drop in tensile stretch properties of the colored fibers is a result of the disruption of the fiber catenary uniformity. This disruption of the fiber catenary uniformity may also account for a significant portion of the 2.4% drop in strength for the colored fiber, which would reduce the component of strength reduction caused by the drop in the Spectra® material's properties as a direct consequence of the coloration.

Indirect Application of Multiple Colors to Braid Using Printed Pattern Dye Sublimation Transfer Paper.

In a multi-color exemplary embodiment, a sample of Spectra® 435 Denier Braid simulated fishing line was colored using the multiply colored “Aqua Blue/Black Stripe/Steelhead Grey” color pattern dye sublimation transfer sample. The colorization process resulted in a fully infused coloration of the fibers in the braid. The color and pattern itself appeared highly suitable as camouflaged fishing line, and likely suitable for other applications where a blue/grey camouflage color pattern is desired. Due to the inhomogeneity, non-uniformity and presence of defects and knots in the braid, the braid was used only for coloration demonstration purposes and no mechanical testing results were reported for this braid sample.

Additional details with regards to material, process, methods and manufacturing, refer to U.S. Pat. No. 5,470,062, entitled “COMPOSITE MATERIAL FOR FABRICATION OF SAILS AND OTHER ARTICLES,” which was issued on Nov. 28, 1995, and U.S. Pat. No. 5,333,568, entitled “MATERIAL FOR THE FABRICATION OF SAILS,” which was issued on Aug. 2, 1994, and U.S. patent application Ser. No. 13/168,912, entitled “WATERPROOF BREATHABLE COMPOSITE MATERIALS FOR FABRICATION OF FLEXIBLE MEMBRANES AND OTHER ARTICLES,” which was filed Jun. 24, 2011; the contents of which are hereby incorporated by reference for any purpose in their entirety.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of any or all the claims. As used herein, the terms “includes,” “including,” “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, no element described herein is required for the practice of the invention unless expressly described as “essential” or “critical.”

Although applicant has described applicant's preferred embodiments of this invention, it will be understood that the broadest scope of this invention includes modifications such as diverse shapes, sizes, and materials. Such scope is limited only by the below claims as read in connection with the above specification. Further, many other advantages of applicant's invention will be apparent to those skilled in the art from the above descriptions and the below claims

SYSTEMS AND METHODS FOR THE TRANSFER OF COLOR AND OTHER PHYSICAL PROPERTIES TO FIBERS, BRAIDS, LAMINATE COMPOSITE MATERIALS, AND OTHER ARTICLES

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