High performance moldable composite

Abstract

A moldable composite with high heat resistance and noise absorption properties utilizes nonwoven fabrics and a heat resistance additive. The composition that provides both superior acoustic performance and excellent flex modulus that may be utilized in automotive products and applications in interior and exterior structures. A blowing agent may be utilized to create micro porous cells in a polymer non-woven structure. The cells or voids make the material lighter and allow the material to have superior acoustic properties that are useful in automotive applications.

Claims

1. A formable automotive structural non-woven composite comprising: a blend of fibers having a plurality of high melt fibers and a plurality of low melt fibers to form a first nonwoven composite layer; the blend of fibers further including a high melt carrier fiber of polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), and a low melt binder fiber made of polyethylene glycol (PETG), Polylactic acid (PLA), Isophthallic modified PET, polyethylene, or polypropylene; at least one of the high melt carrier fiber or the low melt fiber is a non-flame retardant fiber containing an internal flame retardant selected from the group consisting of polyphosphonates, organophosphates, phosphonates, antimony trioxide and any combination thereof; the high melt carrier fiber and low melt binder fiber having at least a 10 C. (19 F.) difference in melt temperatures to allow the low melt fiber to melt during processing and stick to the high melt fibers; a meniscus formed between bond points of the high melt carrier fiber and low melt binder fiber when the low melt binder fiber is melted and flows into interstitial spaces between the high melt carrier fiber and low melt binder fiber; the first nonwoven composite layer having improved acoustic impedance due to a decreased nonwoven web pore sizes created by the low melt fibers when amorphous portions of the low melt binder fiber are melted during bonding wherein air flow resistance through the formable automotive structural non-woven composite is decreased due to the decreased web pore sizes and attributable to increased acoustic properties of the formable automotive structural non-woven composite; a blown film layer disposed onto the first nonwoven composition layer as a second nonwoven composite layer and forms a multi-layer nonwoven composite, the blown film layer having controlled micro-porosity of the film for restricting air flow and furthering acoustic impedance properties of the formable automotive structural non-woven composite; and wherein the blend of fibers further having a physical properties including a flexural modulus sufficient for automotive structural use, and heat resistance to withstand automotive engine compartment conditions and the formable composite is used as an automotive structural component for use in areas around the engine compartment or under the vehicle.

2. The formable composite of claim 1 further including a second nonwoven composite layer, the fibers having a plurality of high melt fibers and a plurality of low melt fibers, and the second layer attached to the blown film layer to form a tri-laminate.

3. The formable composite of claim 1 wherein the blend of fibers further include fiber material selected from the group consisting of polyester, nylon, acrylic, polypropylene, Polylactic acid, fiberglass and any combination thereof.

4. The formable composite in claim 1, wherein the high melt fiber and low melt binder fiber both further include a flame retardant.

5. The formable composite of claim 1 wherein the fibers are from 0.9 to 50 deniers.

6. The formable composite of claim 1 wherein the fibers are from 25 mm (1) to 180 MM (7.1) in length.

7. The formable composite of claim 1, wherein the blend of fibers further include fibers that are both high melt temperature fibers and low melt temperature fibers, and wherein the low melt and high melt temperature fibers are selected from a group consisting of polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), polypropylene (PP), polyvinylchloride(PVC), polyethylene terephthalate(PET), polyethylene terephalate glycol-modified (PETG),polyamide (Nylon), Ethylene Vinyl Acetate, Isophthalic modified PET, and any combination thereof.

8. The formable composite of claim 1 wherein the high melt temperature fibers range from 30 to 95% by weight in content.

9. The formable composite of claim 1 wherein the low melt temperature fibers range from 5 to 70% by weight in content.

10. The formable composite of claim 1 wherein the fibers range from 0.7 to 100 denier and a length from 12 mm to 180 mm (0.5 to 7).

11. The formable composite of claim 1 further includes a second a blown film layer combined with the first composite layer or a second blown film combined with the first composite layer and the second composite layer.

12. The formable composite of claim 1 wherein the blown film is defining holes formed using an inert gas during an extrusion process.

13. The formable composite of claim 12 furthering including use of an inert gas is selected from a group consisting of air, nitrogen, carbon dioxide, carbon monoxide, helium, argon, oxygen, and any combination thereof.

14. The formable composite of claim 13 wherein the holes in the blown film are formed using a blowing agent blended with the film at a weight percentage of 0.2% to 3.0%.

15. The formable composite of claim 1 wherein the holes in the blown film are formed using a blowing agent blended with the film at a weight percentage of 0.2% to 3.0%.

16. The formable composite of claim 1 wherein each nonwoven fabric layer is 50 grams per square meter (gsm) to 2000 grams per square meter (gsm).

17. The formable composite of claim 1 wherein the each nonwoven fabric layer is 50 grams per square meter (gsm) to 1,200 grams per square meter (gsm).

18. The formable composite of claim 1 wherein the porosity of air flow measures greater than 1.5 M-RAYLS.

19. The formable composite of claim 1 wherein the low melt binder fiber is blended with natural fibers such as cotton, wool, flax, jute, or mineral fibers.

20. The formable composite in claim 1 wherein the low melt binder fiber is between 5% and 75% of the composite.

21. The formable composite of claim 20 wherein the flame resistance rate is V-0.

22. A method of making a formable automotive structural non-woven composite, comprising: extruding a high melt and a low melt nonwoven polymeric fibers and incorporating a flame resistant additive into the low melt fiber having at least one region defining holes to create a microporous open cell structure for acoustic impedance, and heat and flame resistance.

23. The method of claim 22 wherein the flame resistant additive is a polyphosphonate.

24. The method of claim 23 wherein the extruding is done below 290 C. to avoid degradation of the polyphosphonate.

25. A method of making a formable automotive structural non-woven composite, comprising: compounding a flame retardant into a carrier fiber, wherein the flame retardant is supportive to provide heat resistance to withstand automotive engine compartment conditions and the flame retardant is selected from a group consisting of polyphosphonate, organophosphates, phosphonates, antimony trioxide, halogens and any combination thereof; and wherein the carrier fiber is selected from a group consisting of polyethylene glycol (PETG) cyclohexanedimethanol (CHDM), polyester, nylon, acrylic, polypropylene, polylactic acid, fiberglass, and any combination thereof; said compounding done below 290 C. with no heat history; drawing the carrier fiber at a low draw ratio of approximately 2-2.5 to prevent crystallinity from occurring thereby creating an amorphous carrier fiber; and creating a nonwoven web material having pores by combining the carrier fiber with a blend of fibers having physical properties that includes a flexural modulus sufficient for automotive structural use, wherein amorphous fibers will melt at a lower temperature filling the pores within the nonwoven material to block air and create resistance for sound.

26. The method of making a formable automotive structural non-woven composite of claim 25, further comprising: combining a first layer nonwoven material having improved acoustic impedance due to decreased nonwoven web pore sizes with a blown film layer to form a multi-layer nonwoven composite, the blown film having controlled micro-porosity of the film for restricting air flow and furthering acoustic impedance properties.

27. The method of making a formable automotive structural non-woven composite of claim 26, further comprising: combining a second layer nonwoven material to the blown film layer, and forming a tri-layer composite material that has acoustic impedance properties, moisture resistance, structural integrity, and heat resistance to withstand environmental conditions inside an automobile engine compartment and underneath the automobile's undercarriage and wheel wells.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a flow diagram showing one embodiment of manufacturing a composition in accordance with the present disclosure.

(2) FIG. 2 is a cross-sectional view of one embodiment of a composition in accordance with the present disclosure.

(3) FIG. 3 is a cross-sectional view of one embodiment of a composition in accordance with the present disclosure.

(4) FIG. 4 is a flow diagram illustrating applying finishing material on the composite for heat exposure in automotive applications.

(5) FIG. 5 is a chart showing the Noise absorption results for samples tested.

(6) FIG. 6 is a photomicrograph of a sample showing the melted portions of one of two fibers that decreases pore size to increase acoustic properties.

DETAILED DESCRIPTION

(7) In experimental trials, black 6d PET was produced with the formula which resulted in 2,500 ppm of Polyphosphinate in the fiber: Clean, PET Bottle flake 92.8%; Americhem 33558-F1 5.0% Black Pigment 50% in PE 2.2%.

(8) These fibers were blended with Black PETG 4 denier fibers to produce a needle-punched nonwoven at a weight of 1,000 grams/ Meter.sup.2. After molding, the product passed the UL 94 test with a V-0 rating. Fibers can be made from 0.9 denier to 50 denier in lengths from 25 mm to 180 mm.

(9) However, incorporating the polyphosphinate into the low melt fiber such as PETG, Isophthalic modified PET, or polyethylene would allow extrusion at lower melt temperatures and ensure there is very little degradation of the polyphosphinate which is susceptible to significant degradation above 290 C.

(10) A low melt fiber that incorporates a flame retardant such as polyphosphinate, organophosphates, phosphonates, antimony trioxide, or even halogens, would be able to be blended with untreated fibers such as cotton, wool, flax, jute, or hemp. The low melt fiber could be blended with all higher melt fibers that have a melt temperature at least 10 C. (19 F.) higher than the low melt fiber.

(11) By blending either high melt fibers with an internal flame retardant with untreated low melt fibers or by blending untreated high melt fibers with an internal flame retardant low melt fiber, a moldable composite suitable for automotive applications requiring heat stability and excellent flame resistance can be produced.

(12) Further, blending a high melt fiber with internal flame retardant with a low melt fiber with an internal flame retardant produces composites with superior flame resistance.

(13) Blending a low melt fiber with internal flame resistance with a natural fiber such as: cotton, wool, flax, jute, or hemp allows the use of non-inherent flame resistant fibers to be used in moldable composites. Some of these fibers are naturally resistant to high heat applications, but cannot be used because they burn easily. This eliminates the need to apply topical flame retardants which could cause harmful chemicals to touch the personnel using these moldable composites.

(14) Further, nonwoven fabrics can be made by many processes including but not limited to: Needle Punch, Spun-Lace, Thermal Bonded, AirLaid and Through Air Bonding.

(15) Moldable composites can be made in weights from 50 to 2,500 grams per square centimeter. Fibers can be made from 0.7 denier to 100 denier and in lengths from 0.5 to 7 inches for these applications.

(16) The high melt fibers can range from 30 to 95% of the blend while the low melt fibers can range from 5 to 70% of the blend. The flame retardant additives can range from 0.1 to 7% of the total fiber by weight. Bi-Component polyester fibers with a low melt sheath are widely used within the automotive industry for moldable composites. But, generally, these do not meet the stringent requirements for the UL-94 flame test. By incorporating the flame retardant additives shown above in either the core or the sheath of the fiber, these bi-component fibers could be used in automotive moldable composites to meet the UL-94 test.

(17) Blowing agents in film may be utilized to make a bi-layer (two layers) or tri-layer (tri-lament)with three layers composite with controlled micro-porosity. In addition various combination may be used such as 2 film layers with a single composite layer or 2 film layers with 2 composite layers. Various combinations of the total layers may be used such as placing the film layer between the two composite layers, or having two film layers outside and attached to a single composite layer. Layers may be alternated such as film, composite layer, film, composite layer or composite layer film, composite layer, film as well as various other combinations depending on the embodiment. While flame-retardants can easily be incorporated into the extruded film, it is preferable to incorporate the flame retardants into the fibers on either side of the film as the fabric is the first material to be exposed to the flame.

(18) Moldable nonwoven fabrics depend on the blending of fibers with high melt temperatures and fiber of low melt temperatures. The high melt temperature fibers used are Polyester (PET), PBT, Polyamide (Nylon 6 or Nylon 6,6), Acrylic, polypropylene, Polylactic Acid (PLA) and fiberglass. In addition, natural fibers that do not melt can be used, such as: cotton, wool, flax, jute, or hemp, and the like.

(19) Low melt fibers such as: Polyethylene, Isophthalic modified Polyester, PETG, and co-PLA can be used as the binder fibers to provide stiffness and durability.

(20) Generally there is at least at 10 C. (19 F.) difference in melt temperatures (and usually greater) to allow the low melt fiber to melt and stick to the high melt fibers. PETG fibers that are amorphous typically may have a melt temperature of 160-165 C. Eastman Chemical, SK Chemicals, and Artenius Italia are manufacturers of PETG. Cyclohexane dimethanol (CHDM) can be added to the polymer backbone in place of ethylene glycol. Since this building block is much larger (6 additional carbon atoms) than the ethylene glycol unit it replaces, it does not fit in with the neighboring chains the way an ethylene glycol unit would. This molecular structure interferes with crystallization and lowers the polymer's melting temperature. In general, such PET is known as PETG or PET-G (Polyethylene terephthalate glycol-modified). The most common Eastman PETG types used during the experiments were: 6763; 14471; and GN-071.

(21) Nonwoven Network, LLC pioneered a Tri-layer product known as Raptor that contains a 500 gsm (grams per square meter) polyester absorber layer, and 150 gsm PP film layer acting as a barrier layer, and a 375 gsm polyester absorber layer. This product provides superior sound attenuation qualities and also has an impervious layer that prevents water from penetrating to the metal frame of the vehicle.

(22) Further, Nonwoven Network LLC has developed a new concept in acoustic noise reduction from the wheel wells, especially in Sport Utility Vehicles. Raptor is a tri-laminate composite that incorporates an absorber layer-barrier layer-absorber layer to dramatically reduce the noise in the cabin with vehicles with large tires and aggressive treads. The product is in full production in a recently launched vehicle and has received outstanding reviews for sound and durability.

(23) The Tri-Layer Raptor product has the best acoustics for a 1,015 gsm product, however there is a need to improve its performance while keeping the weight at the same level.

(24) The invention utilizes a low melt fiber made from a co-polyester where cyclohexane dimethanol (CHDM) has been substituted for some of the ethylene glycol (EG) normally polymerized with Purified Terephthalic Acid to produce Polyester (PET). The result is a polymer called PETG. The melting point of the polymer can be adjusted from 110 C. to 170 C. by adjusting the ratio of CHDM to EG.

(25) The PETG will be blended with Standard PET fiber that has been heat set to 190 C.

(26) Fibers made from Polylactic Acid (PLA) such as fibers made from Cargill's PLA Ingeo polymer the have been drawn and fully crystallized with a melting point of 140 C. and above are blended with Polyester (PET) fibers that have been heat set at 170 C. or above.

(27) The plastics industry has used Blowing Agents to expand the plastic films and injection molded parts by injecting inert gasses such as N.sub.2 (Nitrogen) or CO.sub.2 (Carbon Dioxide). The first known use was in 1846 when Hancock received a patent to make synthetic sponges with rubber. Other blowing agents such as Sodium Bi-Carbonate (Commonly known as Baking Powder) have been used in bakery products (cakes) and plastics. Ethylene Carbonate decomposes with heat to produce CO.sub.2 Ammonium Nitrate decomposes with heat to produce N.sub.2.

(28) Examples of companies that make Blowing agents for plastic extrusion include Techmer, Clariant, Reedy, Kibbechem, Wells, and Beryl for example.

(29) It is also possible to inject inert gasses directly into the extruder as shown by Linde Industrial gasses such as Nitrogen, Argon, Helium, and Carbon Dioxide and the like.

(30) Further blending in a blowing agent at a rate of 0.1 to 3.0% will provide inert gasses to allow a producer to make the film lighter in weight at the same thickness. Alternatively, by maintaining the same film weight, the thickness increases. The additional thickness can increase the flexural modulus, thus producing a stiffer part.

(31) By combining the blown film with 1 or 2 fabric layers, a thermo-formable composite can be made. The blown film is protected by the fabrics. Since the fabrics contain a high percentage of low melt formable fibers, a very stiff and durable composite can be formed.

(32) The following are examples given to illustrate the benefits of the present invention. These examples are in no means meant to limit the invention to these particular embodiments.

EXAMPLE 1

(33) In the first example, GA24, the following was used:

(34) Layer 1: 200 gsm 70% Type P110 6d Black Polyester/30% Black 4 denier PETG.

(35) Layer 2: 150 gsm Blown HDPE film with 1.0% Techmer Blowing agent.

(36) Layer 3: 650 gsm 70% Type P110 6d Black Polyester/30% Black 4 denier PETG

(37) Total weight 1,000 gsm

(38) The Extrusion temperature was 210 C. to achieve full blowing potential. The products were molded using a 210 C. oven to preheat the composite assuring that the 165 C. melt point of the PETG fiber was achieved.

(39) The result was a very stiff molded part with excellent flexural modulus.

(40) The molded composite was tested for RAYLS and found to be very high with little porosity, but with some porosity. It was then subjected to Acoustic testing with excellent results.

(41) The molded composite withstood long term heat and environmental aging.

EXAMPLE 2

(42) In the second example, GA25 the following was used:

(43) Layer 1: 200 gsm 70% Type P110 6d Black Polyester/30% Black 4 denier PETG

(44) Layer 2: 100 gsm Blown HDPE film with 1.0% Techmer Blowing agent

(45) Layer 3: 700 gsm 70% Type P110 6d Black Polyester/30% Black 4 denier PETG

(46) Total weight 1,000 gsm.

(47) The Extrusion temperature was 210 C. to achieve full blowing potential. The products were molded using a 210 C. oven to preheat the composite assuring that the 165 C. melt point of the PETG fiber was achieved.

(48) The result was a very stiff molded part with excellent flexural modulus.

(49) The molded composite was tested for RAYLS and found to be very high with little porosity, but better than GA24. It was then subjected to Acoustic testing with excellent results.

(50) The molded composite withstood long term heat and environmental aging.

(51) It was determined that the composites could be made with other blends of Polyester, Polypropylene, Nylon, Cotton, or other types of fibers. Other binder fibers could also be used.

(52) The extruded film could be made from any thermoplastic resin such as LDPE, LLDPE, HDPE, Polypropylene, PVC, PET, Polyamide (Nylon), EVA and the like.

(53) Adverting to the drawings, FIG. 1 illustrates a flow diagram of one embodiment of extruding the bi and/or tri layer composite composition. As shown, extruder 10 may be a standard single screw or twin screw extruder depending on the embodiment. A resin 14 is place in the extruder's hopper with blowing agent 16. The resin 14 may be among other things any polyolefin such as but not limited to HDPE, LLDPE, LDPE, and the like. Resin 14 may also be any of the polymers mentioned in specification and claims. Blowing agent 16 may be a chemical blowing agent as previous described and/or a gas injected blowing agent depending on the embodiment.

(54) The extruder 10 has a mixing screw 12 that melts the resin pellets and mixes the blowing agent to generate microscopic voids. The voids are preferably open cell holes for use in acoustic impedance as described herein. An extrusion die 18 sets the film thickness of the polymer. And creates a film 20 with the microscopic voids or holes.

(55) Depending on the implementation of either a bi-layer or tri-layer composite material, a fabric (non-woven) layer 22 is released from roll 23 and may or may not be stretched or worked, depending on the embodiment, for nonwoven fabric 27 to be attached to film 20 by nip rolls 28.

(56) In a tri-layer composite implementation, another fabric (non-woven) layer 24 is released from roll 25. Again the nonwoven layer may or may not be stretched or worked, depending on the embodiment, for nonwoven fabric 26 to be attached to film 20 by nip rolls 28. Nip rolls 28 may or may not be chilled or heated depending on the embodiment. Nip rolls 28 also use mechanical pressure to squeeze the layers together. Nonwoven fabric may be made of any compositions discussed in this specification. PETG, Polyethylene, isophthallic modified PET, and/or PLA may also be used as binders in the non-woven fabric. Examples of non-woven materials include for example, and are not limited to, cellulosic, keratin, wool, cotton, polyesters, fabric, polylactic acids, nylons, rayon, polypropylene, and any combination thereof. In either a bi-layer or tri-layer composite the grams per square meter (gsm) of each layer may be controlled by nips 28 and/rollers 23, 25, and/or the line speed of the extrusion line and/or the amount of blowing agent 16. In a tri-layer composite embodiment 29, for example layer 1 of a nonwoven material may be 1-200 gsm, layer 2 of a blown film may be 1150 gsm, and layer 3 of a nonwoven fabric may be 650 gsm, for example.

(57) FIG. 2 illustrates a moldable end product 200 of the extrusion process shown in FIG. 1 using a tri-layer composite end product. In FIG. 2, a layer of moldable polyester 210 having a 200 gsm is used. The second layer 220 is the blown film layer and in this example made of high density polyethylene (HDPE) with a 150 gsm. The third layer is a nonwoven moldable polyester 230 having a 650 gsm. The microscopic holes or cells in the blown film 220 assist with the acoustic impedance quality of the moldable material 200. This composite 200 now may be molded in any shape for automotive or other uses to assist in sound quality and acoustic impedance.

(58) FIG. 3 illustrates a moldable end product 300 of the extrusion process shown in FIG. 1 using a bi-layer composite end product. In FIG. 3, a layer of moldable fabric 310 having a 650 gsm is used. The second layer 320 is the blown film layer and in this example made of high density polyethylene (HDPE) with a 100 gsm. No third layer is used in this embodiment. The microscopic holes or cells in the blown film 320 assist with the acoustic impedance quality of the moldable material 300. This composite 300 now may be molded in any shape for automotive or other uses to assist in sound quality and acoustic impedance.

(59) Additional materials may also be applied to any fibrous element. For example, the PTEG or PLA fibers or any of the non-woven materials or blown film described above may be treated with a performance enhancing finish, either during fiber formation or fiber blending. The finish types may vary depending on the embodiments. In some embodiments, the finish is comprised of a fluorocarbon, such as the CF fluorocarbon sold by Goulston Technologies as FC-L624. This enhances among other things the durability and moisture resistance of the moldable fabric. In other embodiments, the finish is comprised of an inorganic phosphate salt, such as that sold by Goulston Technologies as L-14951. This enhances additive also enhances the heat resistance and flame retardant and/or durability of the moldable fabric. In either instance, the performance enhancing finish preferably does not exceed 0.05% to 1.0% of the fiber weight. An alternate finish may also be comprised of a combination of a fluorocarbon and an inorganic phosphate salt to achieve fire retardant characteristics. Preferably, this alternate finish does not exceed 0.05% to 2.0% of the fiber weight. An anti-static element, such as ASY, may also be added to improve run ability, especially when the moldable fiber is manufactured within a low humidity environment.

(60) FIG. 4 illustrates a flow diagram for a non-woven fabric. Shown as an example, PET fiber 400, with PETG fiber 410 and PLA fiber 420 is blended in a blending machine 430. A finishing application 450 is accomplished adding additives for example those shown, but not limited to, additives in block 440. A fabric formation 46 is made that may be further molded as a product as shown in molding fabric 470 or utilized as a nonwoven fabric in the extrusion process explained in FIG. 1.

(61) FIG. 5 illustrates a graph showing significantly reduced noise using the tested fabric. As shown 700 gsm and 1000 gsm samples had superior noise absorption qualities.

(62) FIG. 6 is a photomicrograph showing the decreased pore size in a non-woven material by the melting of one of the two fibers. Decreased pore size is attributable to the increased acoustic properties (noise absorption) of the fabric.

(63) Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.