Patent Application
20150232044
The present disclosure relates to acoustic insulator materials and products used particularly in automobile vehicle applications.
This section provides background information related to the present disclosure which is not necessarily prior art.
Automobile vehicles include acoustic insulation in multiple locations inside and outside a vehicle passenger compartment to reduce vehicle and road noise during operation. Three major methods of noise control are used in vehicles: (1) reducing noise and vibration sources; (2) applying barriers and other treatments to block sound from entering the passenger compartment; and (3) applying sound absorbers in both the exterior and the interior of the vehicle to dissipate sound and thereby reduce overall sound level.
Acoustic insulation made of cotton “shoddy” or fibrous woven or mat material can conform to substantially any vehicle component shape, and may contain thermoplastic fibers or a thermoset resin powder to group the cotton fibers and maintain a mat thickness. The thermoplastic fibers or thermoset resin powder in the acoustic insulation thus act as binders within the mat material and are solid-based (not liquid-based). Known shoddy mat however, has low thermal operating temperature limits (approximately 240 to 250 degrees Fahrenheit maximum) above which the mat droops or loses its shape, and is therefore not used in high temperature locations, or unsupported locations requiring retention of a preformed shape. Known shoddy is therefore commonly used in locations where the shoddy mats are mechanically retained or held in position by other components such as trim or dashboard members. Typically, molded shoddy mat is therefore not currently used in locations where the shoddy is exposed to temperatures above approximately 250 degrees Fahrenheit, such as in engine compartments, locations where the material is positioned horizontally and cannot be supported throughout, or where the material is subject to wind or weather. Known molded shoddy mat also does not meet the Underwriters Laboratory (UL) 94 V-0 automotive standard for burn resistance for high temperature locations (temperatures exceeding approximately 250 to 400 degrees Fahrenheit).
For applications that require rigidity and that must meet the Underwriters Laboratory (UL) 94 V-0 automotive standard, vehicles commonly use fiberglass acoustic insulation in panel form that is molded to a predetermined geometry. Vehicle applications using either the thermoplastic embedded shoddy material insulation panels or fiberglass panels include, but are not limited to applications such as underbody aero shields, dash mats, wheel wells, hoods, cowls, interior tunnels, exterior tunnels, back panel insulators, head liners, interior dash panels and package shelves.
While conventional fiberglass acoustic insulation panels meet the Underwriters Laboratory (UL) 94 V-0 automotive standard for burn resistance, conventional fiberglass acoustic insulation panels create material handling problems. Conventional fiberglass acoustic insulation panels are made up of very small glass fibers. When handled by workers during the manufacturing of the insulation panels, assembly of the vehicle, and/or disassembly of the vehicle for repair or scrapping, these glass fibers cause irritation when they come in contact with exposed skin and can also cause respiratory problems if they become airborne. Accordingly, such workers are often required to wear protective clothing, gloves, and/or respirators. Due to these known material handling problems, fiberglass acoustic panels may be provided with protective cloth scrims on both sides of the fiberglass such that the glass fibers are not exposed. However, such scrims typically do not meet the Underwriters Laboratory (UL) 94 V-0 automotive standards for burn resistance, making their use in high temperature locations less desirable. What is needed is an alternative to conventional fiberglass acoustic insulation panels that meets the Underwriters Laboratory (UL) 94 V-0 automotive standard for burn resistance and does not have the material handling drawbacks of conventional fiberglass acoustic insulation panels.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
According to several aspects, a fibrous acoustic insulator includes a nonwoven mat having at least a first layer of nonwoven material impregnated with a thermoset polymeric material that is liquid-based.
According to other aspects, a fibrous acoustic insulator includes a nonwoven mat having a first layer impregnated with a thermoset polymeric material that is water-based latex. A second layer oppositely facing with respect to first layer is also impregnated with the thermoset polymeric material. An inner layer between the first and second layers is not impregnated with the thermoset polymeric material, therefore defining an untreated, un-impregnated nonwoven material layer, which may be made of shoddy.
According to other aspects, a method for forming a fibrous acoustic insulator includes the steps of: supporting a nonwoven mat using multiple rollers of a rolling machine; guiding the nonwoven mat onto a drum roller of the rolling machine; spraying a thermoset polymeric material onto a first surface of the nonwoven mat; passing the nonwoven mat between the drum roller and a sizing roller such that the thermoset polymeric material penetrates the first surface to less than or equal to about 30% of a thickness of the nonwoven mat; and heating the nonwoven mat to cure the thermoset polymeric material.
Advantageously, the fibrous acoustic insulator disclosed meets the rigidity and flammability requirements for use in high temperature locations of a vehicle (where temperatures exceed approximately 250 to 400 degrees Fahrenheit). Unlike conventional shoddy mats that are prone to droop and lose their shape at high temperatures, the disclosed fibrous acoustic insulator has superior rigidity and retains its shape at high temperatures due to the presence of the thermoset polymeric material in the first layer of the nonwoven mat. The disclosed fibrous acoustic insulator is well suited for high temperature locations and requires less support (fewer retention locations) because it holds its shape. Unlike conventional shoddy mats, the fibrous acoustic insulator disclosed meets Underwriters Laboratory (UL) 94 V-0 automotive standards for burn resistance and other less stringent flammability requirements. At the same time, the disclosed fibrous acoustic insulator provides superior acoustic attenuation and does not have the same material handling drawbacks as conventional fiberglass acoustic insulation panels. As a result, the disclosed fibrous acoustic insulator does not require special handing precautions or scrims.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
Referring to
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An un-impregnated layer 16 is also provided which is not impregnated by the thermoset plastic acrylic latex material, and is therefore untreated, un-impregnated shoddy material. According to several aspects, the first layer 14 can have a thickness “C” which represents penetration of the thermoset plastic acrylic latex to approximately 5 to 30% of the body thickness “B”. Latex impregnated fibrous acoustic insulation mats of the present disclosure with penetration of the thermoset plastic acrylic latex to approximately 5 to 30% of the body thickness “B” and having a final loft or thickness of at least 3 mm will provide sound absorption capability.
Referring to
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According to several aspects, each of the first and second layers 14, 22 can have the common thickness “C” which represents penetration of the thermoset plastic acrylic latex to approximately 5 to 30% of the body thickness “B”. According to other aspects, each of the first and second layers 14, 22 can have a different thickness after impregnation by the thermoset plastic acrylic latex. A thickness “D” of inner layer 16 can therefore vary between approximately 40% up to approximately 90% of the total body thickness “B”. By stiffening the outer portions of the insulation mat 12 using the thermoset plastic acrylic latex, the first and second layers 14, 22 of latex impregnated fibrous acoustic insulation mat 20 create an I-beam rigidity, resisting lateral and torsional bending and acting to retain the mat geometry.
Referring to
A size of acoustic shield 24 is limited only by the available die and molding machine sizes used to create acoustic shield 24 and/or a surface area of the base shoddy mat material available. A length “E” and a width “F” of acoustic shield 24 in one exemplary embodiment are 57 in (144.8 cm) and 24 in (60.9 cm), however these dimensions are provided as examples only. Latex impregnated insulation mats 12, 18 and/or 20 can therefore be modified to create substantially any geometry now provided by similar fiberglass or shoddy components known in the automotive industry.
Referring to
Following the sizing or second step, the latex impregnated fibrous acoustic insulation mat 12, 18, or 20 can be moved to a die/press 46 which in a third step both heats the latex impregnated insulation mat to a temperature of approximately 400 degrees Fahrenheit to cure the thermoset acrylic latex material and can further create the finished shape such as the acoustic shield 24 described in reference to
Referring to
After the first outer surface 60 has been treated with latex thermoset polymeric material 58 and pressed, the partially impregnated shoddy mat can be reversed and re-fed through application machine 54 such that a second outer surface 64, which is oppositely facing with respect to first outer surface 60, has latex thermoset polymeric material 58 applied thereto. The penetration of latex thermoset polymeric material 58 into second outer surface 64 can be to 30% of the body thickness similar to first outer surface 60, or can vary as noted above. According to further aspects, the amount of penetration of the latex thermoset polymeric material 58 can be varied between first and second outer surfaces 60, 64 as desired. Application machine 54 can also be set up to simultaneously spray both the first and second outer surfaces 60, 64. According to further aspects, the latex thermoset polymeric material 58 can be applied to only one of the first or second outer surfaces 60, 64 as desired. Depending on the solids percentage of the latex thermoset polymeric material 58 in the solution, the latex thermoset polymeric material 58 in solution can be applied to one or more surfaces of shoddy mat 10 and allowed to wick or penetrate into shoddy mat 10 to create the one or more layers 14, 22, without the use of applied pressure. However, according to several aspects pressure is applied to the surface having the latex thermoset polymeric material 58 to force penetration of the latex thermoset polymeric material 58 to the desired penetration. As an alternative to applying pressure to the first outer surface 60 and/or the second outer surface 64 to increase penetration of the latex thermoset polymeric material 58, the fluid pressure of the latex thermoset polymeric material 58 may be increased at the spray nozzles 62 to achieve greater penetration into the shoddy mat 10.
As previously noted, after coating with latex thermoset polymeric material 58, insulation mat 12, 18, and/or 22 requires heating to approximately 400 degrees Fahrenheit for approximately 20 seconds to cure latex thermoset polymeric material 58. As previously noted the die and/or press used to create the finished acoustic insulator geometry can provide a heating system such that uncured, latex impregnated insulation mats 12, 18, 22 can be cured at a curing temperature of approximately 400 degrees Fahrenheit by the concurrent application of heat and pressure during the press operation. Alternately, latex impregnated insulation mats 12, 18, and/or 22 can be heated in an oven or by similar heating system to complete the curing process. The impregnated and cured insulation mats 12, 18, and/or 22 can be then moved to a cutting die or other machine to create an acoustic insulator of any desired shape.
In addition to the water-based acrylic latex or water-based acrylic latex foam previously identified herein, latex thermoset polymeric material 58 can also be a urethane, an ionomer, or a co-polymer of any of the above materials, all of which can be treated to meet the Underwriter Laboratory (UL) 94 V-0, V-1, V-2 and/or FMVSS 302 automotive standards for burn resistance. Latex thermoset polymeric material 58 mixed with water to form a solution can be applied as an emulsion and also as a foam.
Referring to
Acoustic shield 24 according to several aspects retains the latex impregnated first layer 14, the latex impregnated second layer 22, and the un-impregnated inner layer 16 in a main body portion 66. Main body portion 66 therefore provides full acoustic attenuation properties. In each of the at least one flange 34, 34′ the inner layer 16 is fully compressed between the latex impregnated first and second layers 14, 22 and the first and second layers 14, 16 are at least partially compressed. A thickness of the flange 34, 34′ can be reduced from the approximate initial body thickness “B” of approximately 20 to 25 mm to a compressed thickness of approximately 1.5. mm. The inner layer 16 at the flanges 34, 34′ and in some aspects the inner layer 16 at the outer walls 32, 32′ is therefore substantially eliminated as an acoustic attenuation material by compression, such that the flanges 34, 34′ and/or the outer walls 32, 32′ provide no acoustic attenuation or provide substantially only the acoustic attenuation properties of the latex impregnated first and second layers 14, 22. According to other aspects, the outer walls 32, 32′ are either partially compressed or are not compressed and therefore the inner layer 16 is at least partially or fully retained in the outer walls. This provides some acoustic attenuation properties in the outer walls 32, 32′.
Referring to
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Latex impregnated fibrous acoustic insulation mats 12, 18 and/or 22 of the present disclosure have similar weight as known fiberglass acoustic panels and have similar thermal and acoustic properties. The rigidity and acoustic properties can be further varied or “tuned” on a case basis by varying the degree of penetration of latex thermoset polymeric material 58. Improvements offered by latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 compared to known fiberglass acoustic panels include increased durability and decreased process time. Where conventional fiberglass acoustic panels can typically require approximately 60 to 90 seconds to form and complete, a latex impregnated fibrous acoustic insulation mat 12, 18, and/or 22 requires only approximately 45 to 60 seconds to complete. Therefore, per unit cost reduction is further achieved by reduced production time per unit part.
Latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 also eliminate the presence of fiberglass fibers in the work area when acoustic panels prepared by the present process are used. Fiberglass fibers are typically present in the work area when conventional fiberglass acoustic panels are produced, when conventional fiberglass acoustic panels are installed in a vehicle, or when conventional fiberglass acoustic panels are removed from the vehicle at the time of repair or scrapping of the vehicle. As such, personnel respirators and protective clothing are often required. Advantageously, such precautions are not necessary when the latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 of the subject disclosure are used. Where the nonwoven material in the latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 is shoddy, fiberglass fibers are completely eliminated and therefore pose no material handling concern. Where the nonwoven material in the latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 is fiberglass, the thermoset polymeric material that is applied to the fiberglass helps reduce the amount of fiberglass fibers that are shed from the latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22. This is because the thermoset polymeric material binds many of the fiberglass fibers together so that they will not separate from the rest of the latex impregnated fibrous acoustic insulation mat 12, 18, and/or 22.
The latex impregnated fibrous acoustic insulation mats 12, 18, 22 of the present disclosure also provide acoustic attenuation at reduced cost compared to fiberglass acoustic panels. Latex impregnated fibrous acoustic insulation mats 12, 18, 22 further provide rigidity compared to commercially known shoddy mats which do not contain latex thermoset polymeric material 58, which thereby permits the acoustic panel formed from latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 to be formed in a required geometry and to retain the geometry. This permits application of latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 in horizontally mounted positions and high temperature locations such as vehicle hood panels where panel sag is not allowed, and in underbody panels such as aeroshields. The thickness of the latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 can also be varied as necessary to tune the acoustic performance while meeting space constraints of the vehicle.
Testing has shown that the latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 of the present disclosure meets Underwriter Laboratory (UL) 94 V-0, V-1, and V-2 automotive standards for burn resistance. There are two types of pre-selection test programs conducted on plastic materials to measure flammability characteristics. The first determines a material's tendency to either extinguish or to spread the flame once ignited and is defined in Underwriters Laboratory (UL) 94. The Underwriters Laboratory (UL) 94 V-0 standard applies to flame retardant materials and requires that burning stops within 10 seconds on a vertical specimen, with drips of particles allowed as long as they are not inflamed. The Underwriters Laboratory (UL) 94 V-1 standard is slightly less stringent than Underwriters Laboratory (UL) 94 V-0 and requires that burning stops within 30 seconds on a vertical specimen, with drips of particles allowed as long as they are not inflamed. The Underwriters Laboratory (UL) 94 V-2 standard is slightly less stringent than Underwriters Laboratory (UL) 94 V-1 and requires that burning stops within 30 seconds on a vertical specimen, with drips of particles allowed, even if they are inflamed. Table 1, set forth below, lists several different variations of the disclosed latex impregnated fibrous acoustic insulation mats 12, 18, and/or 22 and the various Underwriter Laboratory (UL) 94 standards that each respective material meets.
With reference to Table 1, the material designated as A 2.5 Tenowo is a latex impregnated fibrous acoustic insulation mat constructed in accordance with the present disclosure that has a thickness of 2.5 millimeters (mm) and includes a standard polyester scrim. The material designated as A 10.3 Tenowo is another latex impregnated fibrous acoustic insulation mat constructed in accordance with the present disclosure that has a thickness of 10.3 millimeters (mm) and includes a standard polyester scrim. The material designated as A 2.5 NS is another latex impregnated fibrous acoustic insulation mat constructed in accordance with the present disclosure that has a thickness of 2.5 millimeters (mm) and is provided without a scrim. The material designated as A 10.3 NS is another latex impregnated fibrous acoustic insulation mat constructed in accordance with the present disclosure that has a thickness of 10.3 millimeters (mm) and is provided without a scrim. The material designated as A PFG 2.5 mm is another latex impregnated fibrous acoustic insulation mat constructed in accordance with the present disclosure that has a thickness of 2.5 millimeters (mm) and includes a performance polyester scrim. Finally, the material designated as A PFG 12.7 mm is another latex impregnated fibrous acoustic insulation mat constructed in accordance with the present disclosure that has a thickness of 12.7 millimeters (mm) and includes a performance polyester scrim. One difference between the standard polyester scrim and the performance polyester scrim is the air-flow permitted through the scrim. There is greater air-flow restriction through the performance polyester scrim because the polyester fibers are more closely set. Accordingly, the performance polyester scrim creates a more arduous path for sound to travel through because the porosity of the performance polyester scrim is less than that of the standard polyester scrim.
The process of the present disclosure uses water-based acrylic latex as the thermoset polymeric material. During processing two surfaces can be bonded together, including a first substrate to a second substrate, a substrate to a scrim, a substrate to a barrier, a substrate to a foil or substrate to a film.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
The present application claims the benefit of U.S. Provisional Application No. 61/939,839, filed on Feb. 14, 2014. The entire disclosure of the above application is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61939839 | Feb 2014 | US |
