Patent Description:
<CIT> describes a multilayer sound attenuating trim part for a vehicle having two fibrous layers and one air permeable intermediate film layer.

It is generally considered desirable to reduce the level of noise within a vehicle passenger compartment. External noises, such as road noise, engine noise, vibrations, etc., as well as noised emanating from within the passenger compartment, may be attenuated through the use of various acoustical materials. Accordingly, sound attenuating materials for vehicles, such as automobiles, are conventionally used in the dashboard, in conjunction with carpeting for floor panels, in the wheel wells, in the trunk compartment, under the hood, and as part of a headliner.

Another consideration with regards specifically to vehicular carpet construction is to ensure that any such construction also provides the requisite resistance to OEM compression testing requirements. That is, in addition to noise abatement considerations, vehicular carpet construction must generally satisfy certain limitations on compression and recovery for various specified loading protocols.

With regards to a given carpet construction, the automotive industry has to date made extensive use of expanded polypropylene (EPP) foam stiffener padding in various carpet lay-ups, which then provides corresponding acoustic and compression performance characteristics. Improving on such acoustic and compression features via the use of alternative materials remains an on-going objective along with potential cost reductions.

The invention is defined in the claims. A vehicular carpet construction comprises a first non-woven face layer, a second non-woven layer, a film layer, a shoddy fiber layer of recycled textile fibers and a backing layer of a fiber composition comprising vehicular carpet waste regrind and binder fiber, wherein said fiber composition of said backing layer comprises <NUM>% (wt. ) to <NUM>% (wt. ) binder fiber; <NUM>% (wt. ) to <NUM>% (wt. ) vehicular carpet waste regrind and wherein said fiber composition has a thickness in the range of <NUM> to <NUM> and a density in the range of <NUM>/m<NUM> to <NUM>/m<NUM>, a sound absorption coefficient of greater than <NUM> over the frequency range <NUM> to <NUM> (<NUM>/<NUM> octave) according to the Standard Test Method For Sound Absorption Coefficients by the Reverberation Room Method, ASTM C423-<NUM>.

The present disclosure is directed at fiber compositions for noise abatement and compression resistance for vehicular applications. The fiber composition comprises binder fiber and vehicular carpet waste regrind. The level of binder fiber is <NUM> % (wt. ) to <NUM> % (wt. ) and the level of vehicular carpet waste regrind is at a level of <NUM>% (wt. ) to <NUM> % (wt.

Binder fiber is reference to fiber that has a relatively lower melting point than the nylon or polyamide fiber, polyester fiber or polypropylene fiber present within the vehicular carpet waste regrind, and when heated, serves to bind the vehicular carpet waste regrind that is present. Binder fiber may preferably comprise a polyethylene terephthalate (PET) bicomponent fiber, comprised of two polymers with different chemical and physical properties (e.g. melting points). Accordingly, one may preferably utilize a binder fiber that comprises a sheath-core construction where the sheath is a relative low melting point polyester, made from a copolymer of PET and the core is PET based. The relatively low melting point polyester may preferably have a melting point in the range of <NUM> to <NUM>. More preferably, the relatively low melting point polyester has a melting point of <NUM> to <NUM>, or in the range of <NUM> to <NUM>. It should therefore be understood that in the broad context of the present invention, the binder fiber is not limited to bicomponent fibers, and may include any fiber that provides a melting point in the range of <NUM> to <NUM>. The binder fibers also preferably have a denier (D) value of <NUM>-<NUM> and a length in the range of <NUM> to <NUM>, more preferably <NUM> to <NUM>.

The vehicular carpet waste regrind herein comprises as the primary fiber component one or more of a nylon (polyamide) a polyester or polypropylene fiber that may include a polymeric type coating resin, such as a polymeric latex coating. Such coating is preferably sourced from a polyolefin (e.g. polyethylene or polypropylene). The vehicle carpet waste regrind herein itself preferably contains some amount of polymer that has a melting point in the range of <NUM> to <NUM>, or even more preferably, in the range of <NUM> to <NUM>. The preferred level of such polymer with the aforementioned melting behavior is in the range of <NUM>% (wt. ) to <NUM>% (wt. ), more preferably <NUM> % (wt. ) to <NUM> % (wt. The vehicular carpet waste is then preferably ground or torn to provide the source of vehicular carpet waste regrind material herein. Such vehicular carpet regrind waste can be sourced from vehicle production facilities where it is then conveniently available at relatively lower cost than EPP.

The fiber composition (binder and vehicular carpet waste regrind) can be utilized in a representative carpet construction lay up <NUM> as shown in <FIG>. However, it should be understood that in the broad context of the present invention, such fiber composition can now be utilized in any carpet construction lay-up to replace the use of EPP padding material.

The representative carpet construction in <FIG> includes a face layer <NUM> which is preferably a non-woven layer having a thickness in the range of <NUM> to <NUM>, sourced from PET. Such non-woven may preferably have a basis weight in the range of <NUM>/m<NUM> to <NUM>/m<NUM>. This is followed by a non-woven layer <NUM> that is also preferably sourced from PET, at a thickness of <NUM> to <NUM> at a basis weight of greater than <NUM>/m<NUM> to <NUM>/m<NUM>. Preferably the non-woven layer <NUM> has a higher relative density than the non-woven face layer <NUM>. A polymeric film layer <NUM> is present preferably at a thickness of <NUM> to <NUM>, where such film is preferably selected from a polyolefin polymer, such as polyethylene or polypropylene. A shoddy fiber insulator layer is then present at <NUM> where reference to shoddy is generally understood as recycled textile fibers. The shoddy insulator layer preferably has a thickness of <NUM> to <NUM> at a basis weight of <NUM>/m<NUM> to <NUM>/m<NUM>.

The fiber composition at <NUM> herein preferably serves as the bottom or backing layer of a given carpet lay-up. Such fiber composition is preferably utilized to now replace the use of EPP padding as such bottom or backing layer of a given vehicular carpet construction. The fiber composition at <NUM> is present at a layer thickness of <NUM> to <NUM> and at a density in the range of <NUM>/m<NUM> to <NUM>/m<NUM>. Other preferred thickness values include <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>. Other preferred densities for the fiber composition <NUM> include <NUM> to <NUM>/m<NUM> or <NUM>/m<NUM> to <NUM>/m<NUM>. As can therefore be seen, such vehicular carpet construction illustrated in <FIG> can avoid the use of expanded polypropylene padding.

As alluded to above, the fiber composition <NUM> herein may be used as a backing layer in other representative carpet lay-ups that similarly can avoid the need to utilize expanded polypropylene. <FIG> show representative carpet construction <NUM> that again includes a face layer <NUM>, shoddy layer <NUM> and the fiber composition <NUM> as the backing layer. The face layer <NUM> is once again preferably a non-woven layer having a thickness in the range of <NUM> to <NUM>, sourced from PET. Such non-woven may preferably have a basis weight in the range of <NUM>/m<NUM> to <NUM>/m<NUM>. The shoddy layer <NUM> is once again recycled textile fiber that preferably has a thickness of <NUM> to <NUM> at a basis weight of <NUM>/m<NUM> to <NUM>/m<NUM>.

<FIG> shows representative carpet construction <NUM>. Once again, the face layer <NUM> is present, which is preferably a non-woven layer having a thickness in the range of <NUM> to <NUM>, sourced from PET, and at a basis weight in the range of <NUM>/m<NUM> to <NUM>/m<NUM>. This is then followed by a polyurethane foam layer <NUM> having a thickness in the range of <NUM> to <NUM> and a density in the range of <NUM>/m<NUM> to <NUM>/m<NUM>. The fiber composition backing layer is again shown at <NUM>. The need to utilize expanded polypropylene is again avoided.

<FIG> shows representative carpet construction <NUM>. This is similar to representative carpet construction <NUM> in <FIG> but does not contain film layer <NUM>. The fiber composition backing layer is again shown at <NUM>. The need to utilize expanded polypropylene is again avoided.

<FIG> shows representative carpet construction <NUM>. The construction is similar to representative carpet construction <NUM> in <FIG> where film layer <NUM> is replaced by mass layer <NUM> which is designed to act as a barrier to sound transmission. Mass layer <NUM> may preferably comprise a filled (i.e. calcium carbonate) polyethylene-co-vinylacetate sheet and preferably has a thickness in the range of <NUM> to <NUM> and a basis weight in the range of <NUM>/m<NUM> to <NUM>/m<NUM>. The need to utilize expanded polypropylene is again avoided.

<FIG> shows representative construction <NUM>. This construction includes face layer <NUM> as described herein, mass layer <NUM> as described herein, polyurethane foam layer <NUM> as described herein and the fiber composition <NUM> as the backing layer. The need to utilize expanded polypropylene is again avoided.

As noted, the fiber composition <NUM> herein can fully replace the use of EPP pads in vehicular carpet constructions while providing improved noise abatement and requisite compression performance. Turning first to a consideration of noise abatement, the fiber composition herein demonstrates improved sound transmission loss, insertion loss and absorption coefficient, at key ranges of frequency, as detailed below.

<FIG> provides a plot of sound transmission loss (dB) versus frequency (Hz) (<NUM>/<NUM> octave), according to the general procedures in SAE J1400 Test (July <NUM>, <NUM>), for the fiber composition herein as employed as the bottom or backing layer <NUM> in the carpet construction of <FIG>, where the face layer, non-woven layer, film layer, and insulator layer had a thickness of <NUM>. The fiber composition herein (binder fiber and vehicular carpet waste regrind), identified in <FIG> by the trademark ECOBLEND™, was present at a thickness of about <NUM> at a density of <NUM>/m<NUM>, thereby providing a total carpet thickness of about <NUM>. This was compared with the use of expanded polypropylene padding having a thickness of <NUM> at a density of about <NUM>/m<NUM> on the backside of the same <NUM> carpet construction (face layer, hard layer, thin film and insulator layer). As can be seen, the fiber composition based carpet construction, over the frequency <NUM>-<NUM> (Hz) (<NUM>/<NUM> octave), provided a sound transmission loss (dB) in the range of <NUM>-<NUM> that was consistently better than the carpet construction utilizing EPP. On average, the sound transmission loss improvement of the carpet construction utilizing the fiber composition herein was about <NUM> dB better over the frequency <NUM>-<NUM> (Hz) <NUM>/<NUM> octave.

<FIG> provides the results of an APAMAT-II (Autoneum) insertion loss test, namely a plot of insertion loss (dB) versus frequency (Hz) (<NUM>/<NUM> octave) for the identified samples of either the fiber composition herein or EPP as the bottom layer <NUM>, as applied to a <NUM> thick layup of carpet construction (see <FIG>). Accordingly, the following was applied as the bottom layer of such carpet construction: (<NUM>) EPP at a thickness of about <NUM> at a density of <NUM>/m<NUM> to thereby provide a total thickness of about <NUM>; (<NUM>) the fiber composition herein at a density of <NUM>/m<NUM> at a thickness of about <NUM> to thereby provide a total thickness of about <NUM>; (<NUM>) the fiber composition herein at a density of <NUM>/m<NUM> at a thickness of about <NUM> to thereby provide a total thickness of about <NUM>; (<NUM>) EPP at a thickness of about <NUM> at a density of about <NUM>/m<NUM> to thereby provide a total thickness of about <NUM>. As can be observed, the fiber composition herein when applied to the backside of the carpet construction provides insertion losses in the range of about <NUM> dB at <NUM> (<NUM>/<NUM> octave) to <NUM> dB at <NUM> (<NUM>/<NUM> octave). In addition, it can once again be observed that the fiber composition herein, when applied to the backside of a given carpet construction, outperforms the use of EPP.

Attention is next directed to <FIG> which provides a plot of the sound absorption coefficient (α) versus frequency (Hz) (<NUM>/<NUM> octave) for the identified samples of either the fiber composition herein or EPP, as applied as the bottom layer <NUM> to a <NUM> thick layup of carpet construction (see <FIG>). The sound absorption coefficient is determined according to the general procedures of ASTM C423-<NUM> "Standard Test Method For Sound Absorption Coefficients by the Reverberation Room Method. " Accordingly, once again, the following was applied as the bottom layer <NUM> of such carpet construction: (<NUM>) EPP at a thickness of about <NUM> at a density of <NUM>/m<NUM> to thereby provide a total thickness of about <NUM>; (<NUM>) the fiber composition herein at a density of <NUM>/m<NUM> at a thickness of about <NUM> to thereby provide a total thickness of about <NUM>; (<NUM>) the fiber composition herein at a density of <NUM>/m<NUM> at a thickness of about <NUM> to thereby provide a total thickness of about <NUM>; (<NUM>) EPP at a thickness of about <NUM> at a density of about <NUM>/m<NUM> to thereby provide a total thickness of about <NUM>. As can therefore be observed in <FIG>, over the frequency range of <NUM> to <NUM> (<NUM>/<NUM> octave), the fiber composition herein, as applied as the bottom layer of the carpet construction as shown in <FIG>, indicates a sound absorption coefficient (α) having a value of greater than <NUM>, or more preferably, in the range of greater than <NUM> to <NUM>, and which significantly outperforms EPP in what may be considered a key area of frequency ranges at or below <NUM>.

It should be noted that while the above sound testing utilized the carpet construction in <FIG>, it is contemplated that similar results would apply for the carpet constructions of <FIG>. In addition, as can now be appreciated, such carpet constructions avoid the use of expanded polypropylene foam pads. Accordingly, the present invention provides a carpet construction that indicates one or more of the following: (a) sound transmission loss of <NUM>-<NUM> dB over the frequency range <NUM>-<NUM> (<NUM>/<NUM> octave); or (b) an insertion loss in the range of <NUM> dB at <NUM> (<NUM>/<NUM> octave) to <NUM> dB at <NUM> (<NUM>/<NUM> octave); or (c) a sound absorption coefficient of greater than <NUM> over the frequency range <NUM> to <NUM> (<NUM>/<NUM> octave).

The fiber compositions herein are also such that they compare or exceed the compression performance exhibited by EPP, when utilized in a given carpet construction. For comparison evaluation, the fiber compositions herein were evaluated according to an OEM compression testing protocol (Honda Floor Carpet Specification, PC Spec <NUM>-<NUM>, pp. <NUM>-<NUM>) where as shown in Table <NUM> below, various compression forces in Newtons (N) are applied to the samples undergoing evaluation, along with the identification of the weight that is utilized on the sample to achieve the identified force:.

Table <NUM> below next provides the performance requirements of the samples tested as to whether or not they receive a Class A or Class B designation. As can be seen, the Class B designation identifies relatively lower deflection requirements for the identified loading increments, which thereby identifies a relatively stiffer sample, as compared to the Class A designation.

Table <NUM> below provides the results of comparative testing of the fiber compositions herein versus EPP pads either on their own and in the representative carpet lay-up construction illustrated in <FIG>. It is noted that in Table <NUM>, due to the frame of reference for the measurements recorded, any identified increase in values for D<NUM>, D<NUM>, D<NUM> and D<NUM>, as compared to the initial height D<NUM>, actually represents the amount of compression in mm that the sample realized from the indicated applied force (or weight applied on the sample) after <NUM> minute. For example, for the initial EPP Pad entry, at 200N of force, the EPP Pad underwent a compression of <NUM>-<NUM> = <NUM>.

Table <NUM> provides the analysis of the data in Table <NUM>, identifying the compression performance and determination of either Class A or Class B designations shown in Table <NUM>:.

Claim 1:
A vehicular carpet construction comprising
a first non-woven face layer,
a second non-woven layer,
a film layer,
a shoddy fiber layer of recycled textile fibers and
a backing layer of a fiber composition comprising vehicular carpet waste regrind and binder fiber, wherein said fiber composition of said backing layer comprises <NUM>% (wt.) to <NUM>% (wt.) binder fiber; <NUM>% (wt.) to <NUM>% (wt.) vehicular carpet waste regrind and wherein said fiber composition has a thickness in the range of <NUM> to <NUM> and a density in the range of <NUM>/m<NUM> to <NUM>/m<NUM>,
wherein said carpet construction indicates:
a sound absorption coefficient of greater than <NUM> according to the Standard Test Method For Sound Absorption Coefficients by the Reverberation Room Method, ASTM C423-<NUM>.