Polypropylene films are often used as surface materials for laminates and composite materials, are known for use in lining trucks, refrigerated shipping containers and other industrial and construction materials. Typically, a film such as polypropylene or other substrate such as PET is bonded to a nonwoven The polypropylene face layer is not a suitably durable, temperature resistant or chemically inert surface. The polypropylene facers are generally not suitable for use with a thermoset composite due to adherence issues and temperature resistance. Polypropylene is typically porous arc difficult to clean and is therefore generally not suitable for use for a number of applications. The polypropylene laminate s formed with a film of polypropylene, to which a layer of polypropylene is extruded End the extruded polypropylene adheres to the film and the nonwoven material. The three-step process increases material costs, processing expense and material waste.
In accordance with embodiments, the present invention relates to laminate facings for fiber reinforced or composite materials and materials formed therefrom. The laminate facings are generally formed of a polyester film layer bonded directly to a nonwoven fibrous layer. The facings are cohesively bonded to a nonwoven. typically roil bonded, point bonded or bonded by any other suitable method, including conforming of the fiber layer on the film or the film layer on the fibrous layer directly such that the fibers and the polyester film facing are integrally joined without the use of a subsequently applied layer of adhesive or other polymer. The composite materials may be formed by applying the laminate to a surface and depositing fiber reinforced resin to the laminate or applying the laminate to the surface of a fiber-reinforced resin during manufacture. The laminate provides a rugged outer layer for composite materials and may reduce volatile organic compound emissions by replacing a gel coat layer. The laminate may also include a metalized layer such as aluminum, molybdenum, tantalum, titanium, nickel, and tungsten. The metalized layer improves thermal properties by forming a radiant barrier and also improves opacity of the facing and pro vides an aesthetically pleasing appearance.
In accordance with embodiments of the present invention the films may be produced by conventional forming such as casting, blowing, and extrusion or coextrusion processes. The extruded films are created with a single base layer made from an extrudable thermoplastic polymer and may include one or more exterior layers. One suitable exterior layer includes a relatively low melting point heat sealable polymer to improve he bonding of the film to the fibrous layer. The bonding material of the film is a heat sealable polymer layer designed to melt bond to the polymer of the fiber layer. In an alternate embodiment of the present invention, a metalized or ink layer may be deposited on one surface or both surfaces of the laminate.
Bicomponent fibers may be incorporated into nonwovens by several processes. The spunbond process may be adapted to create bicomponent fibers of a sheath/core type, and lay these fibers continuously onto a conveyor wherein they can be consolidated into a nonwoven web and wound into a roll. Consolidation may be provided by seated rolls either of a pattern including point bonding, or more preferably in this case of smooth surfaces to provide more uniform bonding over the entire surface of the nonwoven web of continuous fibers.
Alternatively, Bicomponent fibers may be produced and then cut and crimped into staple fibers. Staple fibers may then be blended and mixed with other fiber types and dimensions, then carded and run onto a conveyor wherein they can be consolidated into a nor woven web and wound into a roll. Consolidation may be provided by heated rolls either of a pattern including point bonding, or more preferably in this case of smooth surfaces to provide more uniform bonding over the entire surface of the nonwoven web of continuous fibers.
There are several advantages for using staples fiber blends for processing, performance, and cost. A notable difference between the two described methods is that a nonwoven web formed of continuous fibers is formed of layers of superimposed fibers, whereas a nonwoven web of staple fibers has substantial interleaving of the fibers such that each fiber may be present in part on both top and bottom surfaces. While a spunbond line adapted for the production of bicomponent fibers may only provide a singular specification of fiber for a given layer of the nonwoven, a production line using staple fibers may blend several types of fibers throughout the nonwoven web. Staple fiber blending is common and easily controlled, and the benefits of blending can provide enhancements of performance and cost. In addition, a production line using staple fibers may be more easily controlled for speed to provide greater flexibility of the weight of nonwoven achieved as well as the introduction of films into the process.
In accordance with an alternate embodiment of the present invention is presented having a composite material of a laminated facer having a poly ester film with a thickness of 0.5-5 mil and a layer of polyester fibers having a density of 17-100 GSM bonded thereto; and a glass reinforced polymer layer formed on the laminated facer where the polymer of the glass reinforced polymer layer is commingled with the nonwoven of the laminated facer.
In accordance with an alternate embodiment of the present invention is presented having a laminate material having a polyester film having a thickness of 0.5-2 mil, a layer of polyester fibers having a density of 17-70 GSM bonded to the polyester film and a second polymer layer having a thickness of 0.5-5.5 mil joined to the polyester fibers.
In accordance with an alternate embodiment of the present invention is presented having a composite material having a polyester film having a thickness of 0.5-2 mil, a layer of polyester fibers having a density of 17-70 GSM bonded to the film, a second polymer layer having a thickness of 0.5-5.5 mil joined to the polyester fibers and a glass reinforced polymer layer formed on the laminated facer.
A more complete appreciation of the invention and the many embodiments thereof will be readily obtained as the same becomes setter understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
The present invention will now be described with occasional reference to the specific embodiments of the invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, arid so forth as used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless otherwise indicated, the numerical properties set forth in the specification and claims are approximations that may vary depending on the desired properties sought to be obtained in embodiments of the present invent on. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from error found in their respective measurements.
Fibrous nonwoven webs provide an improved bonding surface between a polymer film layer and a fiber reinforced polymer composite material. Preferred nonwoven webs are formed with staple fibers that are carded and then may be bonded with a heat and/or pressure process such as hot calendering, including area bonding, point bonding and embossing; belt calendering; through-air thermal bonding; ultrasonic bonding; or radiant-heat bonding. The web may be additionally, or alternatively, chemically bonded to improve mechanical properties. Many bonding methods are available including powder bonding using a powdered adhesive added to the web and then typically heated. In a preferred embodiment, point or pattern bonding using heated calender rolls or ultrasonic bonding equipment is used to bond the fibers together. Point bonding provides for a secure bonding of the nonwoven to the polyester film while leaving unbonded fibers available to commingie with the composite laminate or other coating resin. Roll bonding may be used to bond the web across its entire surface. Bicomponent or multicomponent staple fibers may be used in the process as well and generally, a blend of single component fibers and bicomponent fibers is preferred.
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The laminate and composite material of the present invention is suitable for use in any composite structures including truck and trailer liners, refrigerated shipping container liners, ladder rails, tool handles, window lineals, structural materials, wall panels for use in food preparation, health care or sanitary applications, wall panels for recreational vehicles, polls and cross arms, pilings or other infrastructure applications, and signage; or electronic materials such as substrates for electronic boards, laminates for solar panels, integrated circuits, industrial switching, capacitors, and electrical boards; and insulation such as foam facers, glass or mineral wool facers, and radiant heat barriers.
Generally, polyester layers are combined with nonwoven layers a wide range of potential laminates is shown in TABLE 1. The polyester film used in each trial ranged from 48 to 200 gauge thickness. The spunbond nonwoven ranges from 34-50 GSM. The PP/Glass composite fiber is 50% glass fibers and 50% polypropylene fibers.
The examples cited in Table 1. Include spunbond continuous monocomponent fibers, (examples 1A, 1B, 2), spunbond continuous bicomponent fibers, (examples 3, 4), and staple (discontinuous) bicomponent fibers blended with monocomponent fibers (examples 5, 6, 7, 8).
Examples 1A and 1B were produced at the same tine, and example 1B had the additional process of application of a coating of Polypropylene applied to the fiber side. They were each then laminated to a similar composite of Fiberglass and Polypropylene. The tests demonstrated an improvement is shear performance with the coating of example 1B.
Example 2 was produced analogous to examples 1 and then additional processed by ultrasonic bonding. Subsequent tests confirmed an increase of peel strength.
Examples 3 and 4 demonstrated improved peel strength when using the continuous bicomponent fibers.
Examples 5, 6, 7, 8 demonstrated further improved peel strength when using the staple (discontinuous) bicomponent fibers blended with monocomponent fibers, and substantially higher shear strength. This was confirmed for a range of film thickness and fiber weights.
In Examples, 3-8 bicomponent fibers having a 50/50 ratio of core to sheath are used. Any suitable multicomponent fiber may be used provided that a relatively low melting point polymer is available at the surface of the fiber for bonding.
The polypropylene layer of example 1B is applied at 108 GSM (˜3.5 mils thick). The use of a second polymer layer improves the strength of the final bond to the composite board, improving the shear strength from 175 PSI to 235 PSI. The use of sheath/core fibers substantially increased the peel and shear strengths.
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The present invention should not be considered limited to the specific examples described herein, but rather should be understood to cover all aspects of the invention. Various modifications, equivalent processes, as well as numerous structures and devices to which the present invention may be applicable will be readily apparent to those of skill in the art. Those skilled in the art will understand that various changes may he made without departing from the scope of the invention, which is not to be considered limited to what is described in the specification.
This Application is a Continuation-In-Part of U.S. application Ser. No. 13/851,662, filed Mar. 27, 2013, which is a Utility Application based upon Provisional Application Ser. No. 61/616,863, filed Mar. 28, 20012, entitled, “Laminate Facing for Fiber Reinforced Materials and Composite Materials Formed Therefrom” with inventor: Thomas Miller. All aspects of Provisional Application Ser. No. 61/616,863 are hereby incorporated by reference.
Number | Date | Country | |
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61616863 | Mar 2012 | US |
Number | Date | Country | |
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Parent | 15353299 | Nov 2016 | US |
Child | 16247029 | US |
Number | Date | Country | |
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Parent | 13851662 | Mar 2013 | US |
Child | 15353299 | US |