The present invention generally relates to nonwoven materials with a voluminous z direction component which have a surface skin added on either one or both sides of the nonwoven.
There are a number of products in various industries, including automotive, office and home furnishings, construction, and others; that require materials having a z-direction thickness to provide thermal, sound insulation, aesthetic, and other performance features. In many of these applications it is also required that the material be thermoformable to a specified shape and rigidity. In the automotive industry these products often are used for shielding applications such as noise and thermal barriers in automotive hood liners and firewall barriers. These automotive materials may or may not have an aesthetic cover material incorporated into the part, which can also protect the core from abrasion, etc. In home and office furnishing, and construction applications these materials are often used as structural elements to which exterior decorative materials might be added.
Additionally, these and other industries require that the materials deliver these properties in a cost effective manner. Often the barrier properties are best accomplished by using specialty fibers and or materials that generate a high level of performance, but also introduce significant cost to the substrate. Especially in a voluminous thickness substrate, the introduction of even a small percent of these materials into the shield material can introduce a significant level of cost to the overall substrate. For this reason composites having specialty surface layers are often used to provide these barrier properties. An example would be a thin layer of high cost but highly effective specialty material laminated to a voluminous lower cost core material. While the resulting composite costs less than more homogenous composites, there are disadvantages such as the need for additional processing steps and the potential delamination of the skin layer.
The present invention is an alternative to the prior art. It is a non-woven material with different functional zones to provide various desired properties of the material localized to the vertically oriented zones where required. Low melt fibers that can be used to construct a “skin” on one, or both, planar sides of the non-woven material can be localized to the sides of the material specifically. The formation of this skin can provide a barrier between the atmosphere and the interior of the non-woven material, can provide a smoother more aesthetically pleasing surface, and can improve other performance features such as abrasion, sound absorption, and rigidity. In the case of a heat shield, the material can become oxygen-starved, due to the lower air permeability of the material skin and facilitate its flame resistance. The invention has superior molding performance because the low melt fibers can be not only optimized in quantity for superior performance, but can also be localized to optimize performance for specific mold design. Superior acoustic properties are achieved by creating a distinct skin on the non-woven with lower air permeability than the core. By using low melt fibers of the same chemical nature as the voluminous core, an essentially single recyclable material can be achieved. All of these benefits are achieved at competitive costs and weight compared to the existing products.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
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As used herein, binder fibers are fibers that form an adhesion or bond with the other fibers. Binder fibers can include fibers that are heat activated. Examples of heat activated binder fibers are fibers that can melt at lower temperatures, such as low melt fibers, core and sheath fibers with a lower sheath melting temperature, and the like. In one embodiment, the binder fibers are a polyester core and sheath fiber with a lower melt temperature sheath. A benefit of using a heat activated binder fiber as the second binder fiber 131 in the non-woven material 100, is that the material can be subsequently molded to part shapes for use in automotive hood liners, engine compartment covers, ceiling tiles, office panels, etc.
As used herein, effect fibers are any additional fibers which may be beneficial to have located in the respective zone, or concentrated near the respective surface. These effect fibers may be used to impart color or functionality to the surface. Effective fibers of color can give the nonwoven material the desired aesthetic appearance. These effect fibers can also include performance fibers such as chemical resistant fibers (such as polyphenylene sulfide and polytetrafluoroethylene), moisture resistant fibers (such as polytetrafluoroethylene and topically treated materials like polyester), fire retardant fibers, or others.
As used herein, fire retardant fibers shall mean fibers having a Limiting Oxygen Index (LOI) value of 20.95 or greater, as determined by ISO 4589-1. Types of fire retardant fibers include, but are not limited to, fire suppressant fibers and combustion resistant fibers. Fire suppressant fibers are fibers that meet the LOI by consuming in a manner that tends to suppress the heat source. In one method of suppressing a fire, the fire suppressant fiber emits a gaseous product during consumption, such as a halogenated gas. Examples of fiber suppressant fibers include modacrylic, PVC, fibers with a halogenated topical treatment, and the like. Combustion resistant fibers are fibers that meet the LOI by resisting consumption when exposed to heat. Examples of combustion resistant fibers include silica impregnated rayon such as rayon sold under the mark VISIL®, partially oxidized polyacrylonitrile, polyaramid, para-aramid, carbon, meta-aramid, melamine and the like.
In one embodiment, the second effect fibers 133 are a bulking fiber. Bulking fibers are fibers that provide volume in the z direction of the nonwoven material, which extends perpendicularly from the planar dimension of the non-woven material 100. Types of bulking fibers would include fibers with high denier per filament (5 denier per filament or larger), high crimp fibers, hollow-fill fibers, and the like. These fibers provide mass and volume to the material. Examples of fibers used as second effect fibers 133 include polyester, polypropylene, and cotton, as well as other low cost fibers.
The non-woven material 100 includes a first planar zone 120 and a second planar zone 130. The first planar zone 120 has a first boundary plane 101 located at the outer surface of the non-woven material 100, and a first zone inner boundary plane 111a located nearer to the second planar zone 130 than the first boundary plane 101. The second planar zone 130 has a second boundary plane 104 located at the outer surface of the non-woven material 100 and a second zone inner boundary plane 111b located nearer to the fire retardant planar zone 120 than the second soundary plane 104. The non-woven material 100 is a unitary material, and the boundaries of the two zones do not represent the delineation of layers, but rather areas within the unitary material. Because the non-woven material 100 is a unitary material, and the first planar zone 120 and the second planar zone 130 are not discrete separate layers joined together, various individual fibers will occur in both the first planar zone 120 and the second planar zone 130. Although
The first planar zone 120 contains first binder fibers 121, first effect fibers 122, second binder fibers 131, and second effect fibers 133. However, the first planar zone 120 primarily contains the first binder fibers 121 and the first effect fibers 122. As such, the first planar zone 120 can have a greater concentration of the first binder fibers 121 than the second planar zone 130, and the first planar zone 120 can have a greater concentration of the first effect fibers 122 than the second planar zone 130. Additionally, the distribution of the fibers in the first planar zone 120 is such that the concentration of the first binder fibers 121 and the first effect fibers 122 is greater at the first boundary plane 101 of the first planar zone 120 than the first zone inner boundary plane 111a. Moreover, it is preferred that the concentration of the first effect fibers 122 and the first binder fibers 121 decreases in a gradient along the z-axis from the first boundary plane 101 to the first zone inner boundary plane 111a.
The second planar zone 130 also contains second binder fibers 121, first effect fibers 122, second binder fibers 131, and second effect fibers 133. However, the second planar zone 130 primarily contains the second binder fibers 131 and the second effect fibers 133. As such, the second planar zone 130 can have a greater concentration of the second binder fibers 131 than the first planar zone 120, and the second planar zone 120 can have a greater concentration of the second effect fibers 132 than the first planar zone 120. Furthermore, the distribution of the fibers in the second planar zone 130 is such that the concentration of the second effect fibers 133 is greater at the second boundary plan 104 than the second zone inner boundary plane 111b. Additionally, it is preferred that the concentration of the second effect fibers 133 decreases in a gradient along the z-axis from the second boundary plane 104 to the second zone inner boundary plane 111b.
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The first binder fibers 121, the first effect fibers 122, the second binder fibers 131, and the second effect fibers 133 are opened and blended in the appropriate proportions and delivered to a cylinder 420. The cylinder 420 rotates and throws the blended fibers towards the collection belt 430 whereby the fibers are collected as they fall from the throwing pattern. The spinning rotation of the cylinder 420 is such that larger denier fibers (the second binder fibers 131 and the second effect fibers 132) tend to travel further than the smaller denier fibers (the first binder fibers 121 and the first effect fibers 122) in the direction of travel for the collection belt 430 before resting on the collection belt 430. Therefore, the web 100′ of fibers collected on the collection belt 430 will have greater concentration of the smaller denier fibers (the first binder fibers 121 and the first effect fibers 122) in the z-direction adjacent to the collection belt 430 at the web first surface 101′, and a greater concentration of the larger denier fibers (the second binder fibers 131 and the second effect fibers 132) in the z-direction further away from the collection belt 430 at the web second surface 104′.
Inherent in the process of forming the web 100′ is the progressive decrease, or gradient, in the concentration of the first binder fibers 121 and the first effect fibers 122, where the concentration of the first binder fibers 121 and the second binder fibers 122 continuously decreases as a function of the distance from the web first surface 101′, adjacent to the collection belt 430, moving towards the opposite or web second surface 104′. Also inherent in the process of forming the web 100′ is the progressive decrease, or gradient, in the concentration of the second binder fibers 131 and the second effect fibers 132, where the concentration of the second binder fibers 131 and the second effect fibers 132 continuously decreases as a function of the distance from the web second surface 104′ moving towards the opposite or web first surface 101′.
After the non-woven web 100′ is formed, it can be heated so that the first binder fibers 121 at least partially melt bond with at least a portion of the first effect fibers 122, and so that the second binder fibers 131 are at least partially melt bond with at least a portion of the second effect fibers 133. This heating step stabilizes the non-woven web 100′ until the process can be completed to form the non-woven material 100, 200, 300. However, it is contemplated that the heating step to stabilized the non-woven web 101′ can be conducted simultaneously with the step of forming of the skin 110 of the non-woven material 100, 200, 300, as disclosed below, by using the same heat source that creates the skin 110.
In the embodiment of the non-woven material 100 illustrated in
In the embodiment of the non-woven material 200 illustrated in
In the embodiment of the non-woven material 300 illustrated in
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In one example of the present invention, the non-woven material was formed from a blend of four fibers, including:
In a second example of the present invention, the non-woven material was formed from a blend of four fibers, including:
The second example of the present invention was tested for air permeability, sound absorption, and abrasion resistance, and compared to a non-woven with the same materials but no skin layer. Sound Absorption was tested according to ASTM E 1050 (ISO 10534-2), Air Permeability was tested according to ASTM D-737, and Martindale Abrasion was tested according to ASTM D-4966. The results of the testing are shown in the table below, where Article A is the non-woven material without a skin and Article B is the non-woven material with the skin:
As can be seen from the results in Table 1, the skin improves sound absorption, reduces air permeability, and improves abrasion resistance.
Although the previous examples describe a non-woven material having a weight of about 7 to 10 ounces per square yard, this weight can vary depending on the end use of the non-woven material. For example, the weight of the non-woven material can be from about 6 to about 15 ounces per square yard if the non-woven material is being used in the ceiling tile industry. Further, the weight of the non-woven material can be from about 15 to about 35 ounces per square yard if the material is being used in the automotive industry. The use of a weight from about 7 to about 10 ounces per square yard for the non-woven material is better suited for the mattress industry.
In an embodiment of the present invention that is suitable for uses such as ceiling tiles, the non-woven material 100, 200, 300, is a semi-rigid material that has a preferred density from about 7.5 to about 9 ounces per square yard. The non-woven material 100, 200, 300, for this embodiment also preferably has at least one smooth surface suitable for printing. Such a smooth surface can be created by keeping the denier of the first binder fiber 121 as small as possible, and creating the skin 110 on this embodiment for the printing surface. The smaller denier of the first binder fiber 121 allows for tighter packing of the fibers, which will create a more dense, continuous (less porous) skin. The most preferred embodiment of the present invention for this application is the non-woven material 300, with the first skin 110 and the second skin 140, where the printing can be done on the first skin 110. Also, the first skin 110 and the second skin 140 on opposite sides of the non-woven 300, creates a stronger more resilient composite that can recover up to 85% of its original thickness in the z direction after being compressed.
Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.
This application claims priority to U.S. application Ser. No. 11/130,749, entitled “Non-Woven Material With Barrier Skin”, filed on May 17, 2005, by inventors David Wenstrup and Gregory Thompson, which is hereby incorporated in its entirety by specific reference thereto.
Number | Date | Country | |
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Parent | 11130749 | May 2005 | US |
Child | 11528014 | Sep 2006 | US |