GLASS FIBER PRODUCT EMBODYING FIBER AGGLUTINANTS Field of the Invention The present invention relates generally to fiberglass products comprising fiber binders and to methods for producing fiberglass products comprising fiber binders.
BACKGROUND OF THE INVENTION Preforms prepared from glass fibers have been used for many years to provide a method for reinforcing polymer composites. The composite manufacturers soon learned that it was very difficult to take prefabricated mats and fabrics prepared with chopped or continuous glass fibers and put them into a mold that contained complex geometric contours. This usually results in wrinkles and creases in the reinforcing material, which causes poor and inconsistent structural integrity. A mat of chopped fibers that can be produced with the signature web form as the final piece and put into the mold before introducing the matrix polymer would provide a much higher reinforcement. The process of molding composite materials using a directed fiber preform can vary drastically. Most preform molding is done using a closed molding process, which means that an embedded mold assembly, using an upper and lower die, is put together to shape the final part. Another option is to use a rigid mold as a base and a flexible top prepared from a sheet or polymer bag, which can be used to compress the material by external forces or as an indirect result of having vacuum applied between the mold halves. The thermosetting matrix resins such as polyester, vinyl ester, urethane and epoxy are typically used to mold the preform. The resin can also be put into the mold with the preform before closing it or it can be transferred, injected or infused directly into the mold after it has been put together. When a manufacturer chooses to produce their own reinforcement preforms, they can buy the glass strands in a continuous form, such as a reel or spool, which significantly reduces their material costs compared to those of a manufactured mat or fabric. The costs for the manufacturer are reduced because the supplier of the fiberglass has reduced the costs of processing and labor in the preparation of the reel (compared to the preparation of a mat or fabric) and because the freight is lower due to the higher density and packaging efficiency of the reel compared to the rolls of carpet. Also, the manufacturer has the freedom to produce fiber preforms of any thickness, length of cut or configuration, which the manufacturer determines desirable for the needs of the final product. The preparation of the directed fiber preforms generally requires that once the reinforcing strands are cut and put into the proper shape, a binder component is applied to hold the strands together. This binder is advantageous to allow the handling of the preform and finally transfer it to the mold. The binder is preferably strong enough to maintain the shape integrity of the preform and still allows flexibility to put it in the mold. Preferably, the type and amount of binder does not interfere with the function of the matrix resin. The binder will preferably not significantly limit fiber wetting nor significantly reduce the flow or curing of the resin during molding.
The binders typically can be thermoset or thermoplastic according to their composition. They can be in the form of a solid or a liquid. Both types of binders require energy to cause the binder to cure or, in the case of thermoplastics, to melt. Liquid binders generally use water as a solvent / vehicle and therefore may require a drying process to remove moisture before use. Various powders and fibers can also be used to mix with chopped glass strands which in this way hold the preform together. These are then heated to cause melting or curing and therefore hold the preform together. Another form of solid binder is a fiber binder. Previously, fiber binders have been prepared from simple polymer compositions to form the synthetic fibers. In order to mix these fibers with the glass fibers, it is desirable that they be composed of a high strength thermoplastic polymer that is strong enough to maintain the integrity of the fiber during the cutting process. The more resistant the polymers may be, the higher temperatures they need to reach their melting point. Therefore, it may be desirable to have a fiber binder melt at significantly lower temperatures and still maintain sufficient strength to process it with the glass fibers.
SUMMARY The present invention provides advantageous fiber binders for use in fiberglass applications. Embodiments of the present invention may be particularly advantageous for use in preform manufacturing processes. A non-limiting embodiment of a fiberglass reel of the present invention comprises a plurality of fiberglass ends and at least one bicomponent fiber binder comprising a core and an outer shell. The core, in a non-limiting embodiment, may comprise polyethylene terephthalate. The cover, in non-limiting embodiments, may comprise polyethylene terephthalate modified with copolyester or glycol. The bicomponent fiber binder may comprise a plurality of bicomponent fiber binder filaments, each filament having a core and an outer shell, and / or a beam comprising a plurality of said bicomponent fiber binder filaments. Each filament of the bicomponent fiber binder, in non-limiting embodiments, can have a denier greater than thirty denier. In non-limiting embodiments of fiberglass reels of the present invention, the outer shell of a bicomponent fiber binder filament comprises at least fifty percent by weight of the fiber binder based on the total weight of the fiber binder. In a further non-limiting embodiment, the outer shell is a filament of a bicomponent fiber binder may comprise at least seventy percent by weight of the fiber binder based on the total weight of the fiber binder. The fiber binder, in a non-limiting embodiment of a fiberglass spool, may comprise more than three weight percent of the glass fiber spool based on the total weight of the fiberglass spool. In another non-limiting embodiment, fiber binder may comprise from three percent to eighteen weight percent of the fiberglass reel based on the total weight of the fiberglass reel. In another non-limiting embodiment, the fiber binder may comprise from three percent to twelve percent by weight of the fiberglass reel based on the total weight of the fiberglass reel. The present invention also relates to fiberglass preforms prepared from fiberglass reels of the present invention that include a bicomponent fiber binder. The present invention also relates to methods for forming fiberglass reels with multiple ends. In a non-limiting embodiment, a method of the present invention comprises providing a plurality of glass fiber ends to a spool winder at a first tension and providing at least one end of glass fiber and a plurality of filaments of fiber binder. bicomponent to the reel winder at a second voltage. Each bicomponent fiber binder filament can have a core and an outer cover. The fiberglass ends and the plurality of bicomponent fiber binder filaments are wound to form a fiberglass spool with multiple ends. In a non-limiting embodiment, the second voltage may be less than the first voltage. The core, in a non-limiting embodiment, may comprise polyethylene terephthalate and the outer shell may comprise copolyester. In another non-limiting embodiment, the core may comprise polyethylene terephthalate and the outer shell may comprise glycol-modified polyethylene terephthalate. In another non-limiting embodiment of a method of the present invention, the at least one fiberglass end and the plurality of bicomponent fiber binder filaments may comprise up to fifty percent by weight of the fiber binder based on the total weight of the at least one fiberglass end and the plurality of bicomponent fiber binder filaments. The at least one fiberglass end and the plurality of bicomponent fiber binder filaments, in another non-limiting embodiment, may comprise from fifteen to fifty percent by weight based on the total weight of the at least one fiberglass end and the plurality of bicomponent fiber binder filaments. In fiberglass reels formed by non-limiting embodiments of the methods of the present invention, the fiber binder filaments may comprise more than three weight percent of the fiberglass reel with multiple ends based on the total weight of the reel. fiberglass with multiple ends. In another non-limiting embodiment, the fiber binder filaments may comprise from three to eighteen weight percent of the fiberglass spool with multiple fiberglass reel ends with multiple ends. The fiber binder filament may also comprise from three to twelve weight percent of the fiberglass reel with multiple fiberglass reel ends with multiple ends.
Detailed Description of the Invention For the purposes of this specification, unless otherwise indicated, it should be understood that all numbers expressing amounts of ingredients, reaction conditions and so on, used in the specification are modified in all cases for the term "approximately". Accordingly, unless otherwise indicated, the numerical parameters set forth in the following specification are approximations that may vary depending on the desired properties desired to be obtained by the present invention. Finally, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be interpreted at least in light of the number of significant digits presented and applying ordinary rounding techniques. Although the numerical ranges and parameters which set forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are presented as accurately as possible. However, any numerical value inherently contains certain errors that necessarily result from the standard deviation found in their respective test measures. Although the numerical ranges and parameters which set forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are presented as accurately as possible. However, any numerical value inherently contains certain errors that necessarily result from the standard deviation found in their respective test measures. In addition, it should be understood that all of the ranges described in this document include any and all sub-ranges included therein. For example, a given range of "a 1 10" should be considered to include any and all subintervals between (both inclusive) the minimum value of 1 and the maximum value of 10; that is, all subintervals that start with a minimum value of 1 or greater, for example, from 1 to 61, and that end with a maximum value of 10 or less, for example, from 5.5 to -10. Additionally, any reference that says "incorporated to this document" must be understood as being incorporated in its entirety. It should also be noted that, as used in this specification, the singular forms "a", "an", "he" and "she" also include plurals unless they are expressly and unequivocally limited to a referent. The present invention relates to fiber binders that can be used advantageously in fiberglass applications. The present invention also relates to fiberglass reels and, in particular, to fiberglass reels with multiple ends. The present invention also relates to methods for producing fiberglass reels with multiple ends. Embodiments of the present invention include advantageous fiber binders for use in preformed manufacturing processes. The present invention also relates to preforms. As used herein, the term "end" means a plurality of individual filaments that are at least partially coated with a binder and that are brought together for later use or processing. One embodiment of a fiberglass reel of the present invention comprises a plurality of glass fiber ends and at least one bicomponent fiber binder. The fiberglass reel may be a multistrand continuous-fiber glass fiber reel assembled with at least one bicomponent fiber binder. The bicomponent fiber binder may be a continuous bicomponent synthetic fiber prepared from thermoplastic polymers having a core and an outer shell. In a non-limiting embodiment, the fiber binder is processed together with the glass fibers, and when properly cut and applied to a preform screen, the fiber binder is dispersed with the glass fibers in the preform. The fiber binders of the present invention are preferably prepared from thermoplastic polymers. The thermoplastic composition of a fiber binder, in another non-limiting embodiment, is such that when heat is applied to the preform, a portion of the fiber binder will melt and come into contact with the glass fibers. When the preform cools the thermoplastic will harden again and create an adhesive between the glass fibers. In addition, the fiber binders useful in the present invention must also have sufficient strength to withstand the mechanical stress of being assembled on a reel while they can still be chopped before being assembled into a preform. In a non-limiting embodiment, the fiber binders of the present invention are produced as bi-component fibers (ie, filaments). The bicomponent fibers can be formed by extruding two polymers from the same row contained within the same filament. In a non-limiting embodiment, a fiber or fiber binder filament comprises a core and an outer cover. The core, in a non-limiting embodiment, comprises a high strength thermoplastic polymer. The high strength thermoplastic polymer provides structural integrity to the fiber binder. The thermoplastic polymer used in the core can be strong enough to resist winding on a reel with fiberglass using a reel winder and strong enough to feed it to a chopper gun, not yet so elastic that it can not be chopped. The thermoplastic polymer of the core, in other words, provides support in the bicomponent fiber binder during the assembly of the fiberglass spool with multiple ends, although it can also be performed well in subsequent processes involving cutting (for example, the preparation of preforms). The thermoplastic core polymer should have a higher melting temperature than the shell polymer. The thermoplastic polymer of the core preferably does not melt during processing, such as the chopping operation. Examples of polymers useful as a core for a bicomponent fiber binder include, without limitation, polyethylene terephthalate, polypropylene, nylon and other polymers having similar performance characteristics. These polymers can be characterized as having a melting temperature greater than 200 ° C and a tensile strength between two and six pounds. Suitable polymers can have a melting temperature between 200 ° C and 325 ° C. In a non-limiting embodiment, the core of the fiber binder comprises polyethylene terephthalate. An example of a suitable polyethylene terephthalate for use in the present invention is CRYSTAR 3915 commercially available in E.I. du Pont de Nemours and Company. As indicated above, the core is surrounded by an outer shell to reinforce the bicomponent fiber binder. In a non-limiting embodiment, the outer shell comprises a thermoplastic polymer. The thermoplastic polymer that forms the outer shell, after the fusion, acts as a binder. For example, in a preform application, once the fiberglass and the fiber binder have been chopped and put into the proper shape, the preform can be heated to melt the thermoplastic polymer in the outer shell, which holds it together the fiberglass preform. The thermoplastic polymers useful as external covers in the embodiments of the present invention may be selected based on the operating / processing temperature of the downstream operation. For example, for fiber binders to be used in fiberglass reels for preform application, the thermoplastic polymer used in the outer shell melts rapidly at temperatures of 130 ° C or higher. The thermoplastic polymers useful as an outer shell of fiber binders for use in preform applications can be strong enough to maintain the integrity of the shape of the preform and still allow sufficient flexibility to put them in the mold. further, the thermoplastic polymer of the outer shell preferably does not interfere with the function of the matrix resin. In particular, the thermoplastic polymer of the outer shell preferably does not limit the wetting of the fibers or significantly reduce the flow or curing of the resin during molding. Examples of polymers useful as an outer shell for a bicomponent fiber binder include, without limitation, copolyester, glycol modified polyethylene terephthalate (PETG), polystyrene and others having similar performance characteristics. These polymers can be characterized as having vitreous transition temperatures between 50 ° C and 100 ° C and viscosities between 1000 and 9000 poise at 190 ° C measured with a capillary rheometer at shear rates between 340 and 3400 seconds in reverse (s "1 In a non-limiting embodiment, the outer bicomponent fiber binder shell comprises copolyester (e.g., coPET) In another non-limiting embodiment, the outer shell of the bicomponent fiber binder comprises glycol-modified polyethylene terephthalate (PETG). Non-limiting embodiment, the outer shell may comprise an isophthalate-modified polyethylene terephthalate A suitable polymer for use in the present invention includes CRYSTAR 3991 commercially available from EI du Pont de Nemours and Company A suitable copolyester is copolyester 20110, which is a PETG with an IV of 0.47 (inherent viscosity) available on the market at Eastman Chemical Company. Non-limiting, most of the bicomponent fiber binder is the outer cover. In a non-limiting embodiment, the outer shell of the bicomponent fiber binder comprises at least fifty percent by weight of the fiber binder based on the total weight of the fiber binder. In another non-limiting embodiment, the outer shell of the bicomponent fiber binder comprises at least seventy percent by weight of the fiber binder based on the total weight of the fiber binder. In an embodiment wherein the core of the bicomponent fiber binder is polyethylene terephthalate homopolymer and the outer shell is polyethylene terephthalate copolymer, the outer shell may comprise between seventy and eighty percent by weight of the fiber binder based on the total weight of the fiber binder. The fiber binders useful in the present invention can be provided in the form of a bundle of bicomponent fiber binder filaments, each filament having a core and an outer shell. A bundle of fiber binders may, in some embodiments, comprise more than fifty filaments. In another embodiment, the bundle may comprise between fifty and two hundred and fifty filaments. The denier of a fiber binder filament, in a non-limiting embodiment, may be greater than thirty denier. In another embodiment, the denier of a fiber binder filament is between thirty and fifty denier. The fiber binders useful in the present invention can be produced according to techniques known to those skilled in the art. The fiber binders of the present invention can be purchased, for example, from Fiber Innovation Technology Incorporated (FIT) of 398 Innovation Drive, Johnson City, Tennessee 37604. An example of a suitable bicomponent fiber binder is DPL 1092, which is available in the market in FIT. A non-limiting embodiment of a fiberglass reel of the present invention comprises a continuous-fiber glass fiber product and a fiber binder of the present invention. In a non-limiting embodiment, a fiberglass spool comprises a plurality of glass fiber ends and at least one bicomponent fiber binder comprising a core and an outer cover. The ends of the fiberglass include a chemical glue that already has the appropriate type of performance characteristics for the desired application. Those skilled in the art will recognize that numerous glass fibers can be used in the embodiments of the present invention. Non-limiting examples of glass fibers suitable for use in the present invention can include those prepared from glass compositions with which fibers such as "glass-E" can be prepared, "glass-A", "glass-C", "glass-S", "glass-ECR" (glass resistant to corrosion), and the fluorine-free and / or boron derivatives thereof. In general, any fiberglass product that is currently used in chopped or continuous glass reinforcement applications for reel products of the present invention can be used. For preform applications, most fiberglass products commonly used in preform applications can be used to form fiberglass reels of the present invention. For example, and without limitation, fiberglass products in preform applications that generally have a high integrity of the strand, can be chopped with a static or minimum dust generation, allow rapid and thorough moistening of the strand bundles, and allow adequate coupling of the matrix resin in the composite.
In a non-limiting embodiment, a glass fiber for use as reinforcement in preform applications comprises a collection of threads comprising 16 micron diameter E-glass fibers treated with a glue that is chemically compatible with multiple thermoset matrix resin systems. An example of such a glass fiber is the PPG 5524 product, which is commercially available from PPG Industries, Inc. The fiber binders and fiberglass reels of the present invention can be used in other binder applications, in addition to preform applications, such as split-thread mats, continuous-thread mats, woven fabrics, and knitted fabrics. The amount of fiber binder that is used in the fiberglass reels of the present invention may depend on numerous factors, including the type of application, the shape and density of the preform, the matrix resin that is used and the total content in glass. In a non-limiting embodiment of fiberglass reels of the present invention, the fiber binder may comprise three percent by weight or more of the fiberglass reel based on the total weight of the fiberglass reel. The fiber binder may comprise up to twenty percent by weight of the fiberglass reel based on the total weight of the fiberglass reel. In other embodiments, the fiber binder may comprise from three to eighteen weight percent of the fiberglass reel based on the total weight of the fiberglass reel. The binder, in other embodiments, may comprise from three to twelve percent by weight of the fiberglass reel based on the total weight of the fiberglass reel. The present invention also relates to preforming made from fiberglass reels of the present invention. The preforms of the present invention can be prepared using techniques known to those skilled in the art. The present invention also relates to methods of forming fiberglass reels with multiple ends that include a fiber binder. In a non-limiting embodiment, a method of forming a fiberglass spool with multiple ends comprises providing a plurality of glass fiber ends to a spool winder at a first tension, - providing at least one end of glass fiber and at least one bundle of bicomponent fiber binder filaments, each filament having a core and an outer shell, to the reel winder at a second tension; and winding the fiberglass ends and the at least one bundle of bicomponent fiber binder filaments to form a fiberglass reel with multiple ends, where the second tension is less than the first tension. In another embodiment, a method of the present invention may further comprise passing the plurality of fiberglass ends through a friction bar assembly before providing the plurality of fiberglass ends to the spool winder. One method of the present invention, in another embodiment, may also comprise passing the at least one fiberglass end and at least one bundle of bicomponent fiber binder filaments through an electronically controlled magnetic tension wheel assembly before of providing the at least one end of fiberglass and at least one bundle of bicomponent fiber binder filaments to the reel winder. In a non-limiting embodiment, a method of the present invention can be implemented by modifying a reel winder from the market to include two different voltage sources. The fiberglass can be fed to the reel winder at high tension and with high friction. This high tension may be necessary to hold the fiberglass ends together while feeding to the reel winder. The fiber binder, in non-limiting embodiments, may not be able to handle the friction and / or stress normally experienced by the fiberglass ends, due in part to the potential for damage and / or breakage of the fiber binder. A majority of glass fibers, in a non-limiting embodiment of the present invention, proceeds by a friction bar tensioning of the conventional type, while a smaller part of the glass fibers together with the fiber binder proceeds by an assembly of electronically controlled magnetic tension wheel. By tensioning with a conventional friction bar, the strands are slowly advanced through a series of off-center ceramic rods to provide tension. In a non-limiting embodiment of an electronically controlled magnetic tension wheel assembly, the assembly comprises two rotating wheels around which the strands move. These wheels may have, in non-limiting embodiments, a width of three to four inches with a diameter of four to five inches. The strands can proceed around each wheel approximately 270 degrees. The strands move in a clockwise direction around the first wheel and counterclockwise around the second. Magnetic brakes provide slow progress to each wheel and, therefore, provide tension to the strands. In a non-limiting embodiment, a small portion of glass fibers together with the fiber binder is provided with tension using the wheel assembly with magnetic tension. The wheel assembly with magnetic tension may be less abrasive and destructive to the fiber binder than the friction bar tensioning of conventional type. In a non-limiting embodiment, the ratio of the small portion of glass fibers to fiber binders in the second supply feed to the coiler is between 1: 1 and 5: 1 by weight. In another non-limiting embodiment, the ratio of the small portion of glass fibers to fiber binders in the second supply feed to the coiler by assembling the wheel with magnetic tension is 2: 1 by weight. The total proportion of glass fibers to fiber binder by weight in a non-limiting embodiment of a finished package can be between 5: 1 and 18: 1. In another non-limiting embodiment, the ratio of fiberglass to fiber binder in a finished package can be between 8: 1 and 10: 1. The fiberglass reels of the present invention, in a non-limiting embodiment, can be formed using a reel winder, such as Model No. 868 or Model No. 858, both commercially available on FTS / Leesona from Burlington. , NC. A wheel assembly with magnetic tension, as described above, can be added to said reel winders to provide a fiber binder to the reel winder according to techniques known to those skilled in the art. When a reel winder such as Leesona 868 is used, the fiberglass and fiber binder ends can be wound at speeds between 500 and 1500 feet per minute. The selection of winding speed is often a compromise between productivity and space limitations. Often, economic considerations govern in the selection of winding conditions. Therefore, any specification related to the winding conditions of the reel winder, unless otherwise indicated, should not be observed as technically limiting the present invention. The operation of an embodiment of the fiberglass reel of the present invention is such that the filaments of the fiber binder will be fed and transferred to the chopping mechanism, cleaned in a clean manner and deposited uniformly with the glass fibers to an assembly of preform screen. The coatings of the fiber binder filaments melt rapidly at a predetermined temperature, such as, for example, at a temperature of 130 ° C or higher. After cooling, the melted covers maintain adhesion between the glass bundles and allow the manufacturer to remove the assembled preform from porous forming die and subsequently put the preform into storage or directly into a mold for use as a reinforcement for a composite material. In the molding process, the assembled preform allows the resin to flow therethrough and even provides penetration so that all the air is removed and all the individual strands have come into contact with the resin. A piece of finished composite material, prepared from a preform comprising a fiber binder of the present invention can show a uniform appearance with very little or no resin-free zone and very little or no obvious defect as a result of irregular or wetting. high content of holes. The fiber binder filaments do not cause visible interruptions or variation in surface texture due to lack of adequate dispersion or compatibility with the matrix resin. Desirable features, which can be shown by the present invention, include, but are not limited to, providing a fiber binder for use with glass fiber as a reinforcement that melts at a significantly lower temperature than conventional fiber binders, providing a spool with multiple ends that can be used to produce a preform with low energy costs for the process, provide a reel with multiple ends that can be used to produce preforms with shorter overall time cycles, provide a fiber binder for use in manufacturing of preforms that results in a lower level of binder waste compared to powder binders, provide a spool with multiple ends that produces a preform with a more uniform concentration of binder, provide a spool with multiple ends that has favorable wetting properties and produces a mate compound with a uniform surface appearance, provide a binder that does not need water or a thermostabilization reaction, provide a binder that does not require moisture removal during production and also that reduces corrosion and other maintenance issues related to transmission systems aqueous, the production of a binder that eliminates emissions that are associated with liquid binders during curing by polymerization (including, for example, improvement of environmental and safety conditions). Various embodiments of the invention have been described in compliance with the various objects of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Therefore, numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention.