Absorptive sound insulation

Abstract

An absorption sound insulation for motor vehicle interiors and luggage compartments with absorption/stiffening nonwovens or 3D absorbers is formed of partially or completely cellulose wool, and includes a wear layer, and an absorbent/stiffening nonwoven fabric laminated thereunder formed of rayon of solid individual phases having a multi-leg cross-sectional shape with at least three legs, in which the legs of the cross-sectional profile each have a length/width ratio of at least 2:1 and the individual titre is 0.5 to 5 dtex.

Claims

1. An absorptive sound insulation for the motor vehicle interior and luggage compartment consisting essentially of two layers: (a) a wear layer, wherein the wear layer comprises (a1) a tufted carpet, (a2) a velour and flat needlepunched nonwoven carpet, and (a3) a microperforated film, or (a4) a PET or blended fibre nonwoven and (b) an absorbent/stiffening nonwoven fabric layer laminated to the wear layer, and comprising rayon of solid individual phases having a multi-leg cross-sectional shape with at least three legs, in which the legs of the cross-sectional profile each have a length/width ratio of at least 2:1 and the individual titre is 0.5 to 5 dtex.

2. The absorptive sound insulation according to claim 1, wherein the absorption/stiffening nonwoven fabric layer contains 5 to 95% by weight of the rayon.

3. The absorptive sound insulation according to claim 1, wherein the absorption/stiffening nonwoven fabric layer consists of rayon.

4. The absorptive sound insulation according to claim 1, comprising a 3D sound insulation geometry manufactured by the fibre flocking process.

5. The absorptive sound insulation according to claim 1, in the form of an interior bulkhead, a floor panelling, thermal insulation, a roof lining, a parcel shelf, a luggage compartment side panelling, an interior wheel arch cover, a spare wheel well, a luggage compartment lid and a load floor.

6. The absorptive sound insulation according to claim 2, wherein the absorption/stiffening nonwoven fabric layer contains 15 to 70% by weight of the rayon.

7. The absorptive sound insulation according to claim 1, wherein the tufted carpet is formed of a yarn material selected from the group consisting of PA6.6, PA6, PP, rPA, PET, and rPET.

8. The absorptive sound insulation according to claim 1, wherein the tufted carpet is formed of a bio-based polyamide selected from the group consisting of PA 5.10 and PA 6.10.

9. The absorptive sound insulation according to claim 1, wherein the tufted carpet comprises a velour and flat needlepunched nonwoven carpet formed of a fibre material selected from the group consisting of PET, PET/PP, PP, PA/PET and rPET.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 plots sound absorption coefficiencies of various rayons in a standard alpha booth;

(2) FIG. 2 plots sound absorption coefficiencies of various rayons in an impedance tube; and

(3) FIGS. 3-5 plots sound absorption efficiencies of various rayons laminated to a tufted carpet (FIG. 3), a velour carpet (FIG. 4), and a nonwoven (FIG. 5).

DETAILED DESCRIPTION OF THE INVENTION

(4) In a first embodiment, subject matter of the present invention is a sound insulation for the interior and luggage compartment of a motor vehicle comprising (a) a wear layer and (b) an absorbent/reinforcement nonwoven laminated thereunder comprising rayon of solid individual phases having a multi-leg cross-sectional shape with at least three legs, in which the legs of the cross-sectional profile each have a length/width ratio of at least 2:1 and the individual titre is 0.5 to 5 dtex.

(5) While the prior art with respect to the above-mentioned fibres was essentially concerned with absorbency, the present invention is devoted for the first time to sound insulation using the above-mentioned fibres in a specific field of vehicle acoustics, in this case the motor vehicle interior and luggage compartment. Particularly preferred in the sense of the present invention are thus the interior bulkhead, floor panelling, incl. insulation, roof lining, parcel shelf, luggage compartment side trim, interior wheel arch cover, spare wheel well, luggage compartment lid and load floor.

(6) No sound insulations are known in the prior art that contain partially or completely rayon made of solid individual phases with a multi-leg cross-sectional shape, wherein at least three legs are present, in which the legs of the cross-sectional profile each have a length/width ratio greater than 2:1 and the individual titre is 0.5-5 dtex.

(7) Particularly preferably in the sense of the present invention, the absorbent/reinforcement nonwoven consists entirely of rayon from solid individual phases with a multi-leg cross-sectional shape with at least three legs, in which the legs of the cross-sectional profile each have a length/width ratio of at least 2 to 1 and the individual titre is 0.5 to 5 dtex. According to the invention, up to 95% by weight of the previously defined rayon can be replaced by other fibres.

(8) In a further embodiment, a microperforated PA/PE film (e.g. 65 m, 50 m PA/15 m PE, hole diameter 0.12 mm) with a nonwoven, for example consisting of 25 wt. % commercially available BiCo fibres [co-PET] and 75 wt. % rayon of solid individual phases with a multi-leg cross-sectional shape was used, wherein at least three legs are present, in which the legs of the cross-sectional profile each have a length/width ratio of at least 2 to 1 and the individual titre is 0.5 to 5 dtex.

(9) A further preferred embodiment consists in the use of a fibre mixture of 35 wt. % BiCo and 65 wt. % rayon of solid individual fibres with a multi-leg cross-sectional shape, wherein at least three legs are present, in which the legs of the cross-sectional profile each have a length/width ratio of at least 2 to 1 and the individual titre is 0.5 to 5 dtex; from which a 3D floor covering insulation was produced in the fibre flocking process known per se.

(10) A preferred fibre blend for sound insulation produced by the fibre flocking process comprises, for example, 25% by weight of BiCo, 20% by weight of PET with good crimp and 55% by weight of rayon from solid individual phases with a multi-leg cross-sectional shape, wherein at least three legs are present in which the legs of the cross-sectional profile each have a length/width ratio of at least 2 to 1 and the individual titre is 0.5 to 5 dtex.

(11) This in turn can be laminated with a standard wear layer of tufted, velour or flat needlepunched nonwoven carpet.

(12) Often intermediate layers, acoustic/reinforcement nonwovens and PE/PA/PE films (closed or micro-perforated) are used.

(13) Essential elements of the present invention are sound insulation structures, in which the acoustic, mechanical and processing properties achieve a requirement-based optimizing/tuning by a target-oriented formulation of the fibre mixture with rayon from solid individual phases with a multi-leg cross-sectional shape, wherein at least three legs being present, in which the legs of the cross-sectional profile each have a length/width ratio of at least 2 to 1 and the individual linear density is 0.5 to 5 dtex.

(14) A further preferred embodiment of the present invention relates to an absorptive sound insulation as defined above, comprising a 3D sound insulation geometry manufactured by fibre flocking (HMP technology).

(15) The material of the wear layer can serve various purposes in the vehicle. Particularly preferably, the wear layer comprises (a1) a tufted carpet, in particular with the yarn materials PA6.6, PA6, PP, rPA and PET, rPET as well as the corresponding bio-based polyamides (PA 5.10; PA 6.10) (a2) a velour and flat needled nonwoven carpet, in particular with the fibre materials PET, PET/PP, PP, PA/PET and rPET, (a3) a micro-perforated film or (a4) a PET or mixed fibre nonwoven.

(16) In particular, the advantage of the present invention is the provision of deformable/stable nonwoven layers comprising or consisting of rayon of solid individual phases with multi-leg cross-sectional shape, wherein at least three legs are present, by which the legs of the cross-sectional profile each have a length/width ratio of at least 2 to 1 and the individual titre is 0.5 to 5 dtex; which are integrated into the material structure of sound insulations; as well as in the fibre mixture of 3D-absorbers with partly or completely rayon of solid individual phases with multi-leg cross-sectional shape, wherein at least three legs are present, in which the legs of the cross-sectional profile each have a length/width ratio of at least 2 to 1 and the individual titre is 0.5 to 5 dtex; produced in the fibre flocking process, and thus new, property-optimised sound insulations can be provided.

EXAMPLE OF EXECUTION

Example 1

(17) To demonstrate the acoustic effectiveness, a 400 g/m.sup.2 and a 600 g/m.sup.2 needle fleece of commercially available rayon [GALAXY VY Faser of Kelheim Fibres GmbH] were produced in each case from solid individual phases with a multi-leg cross-sectional shape, wherein at least three legs are present, in which the legs of the cross-sectional profile each have a length/width ratio of at least 2 to 1 and the individual titre is 0.5 to 5 dtex, in a manner known per se.

Example 2

(18) Furthermore, a 400 g/m.sup.2 (VEGRO 400) and a 600 g/m.sup.2 (VEGRO 600) needled nonwoven in each case of 30 wt. % PET (12 dtex/length 64 mm), 30 wt. %

(19) PET (11 dtex/length 60 mm) and 40 wt.-% PET (6.7 dtex/length 64 mm) are produced.

(20) The absorption measurements, carried out in a standard alpha booth, are shown in FIG. 1.

(21) FIG. 2 shows the results of measurements in the impedance tube, pressed/unpressed.

(22) Figs. clearly show the absorptive efficiency of the sound insulation according to the invention.

Example 3

(23) In application for floor and luggage compartment panellings, the 600 g/m.sup.2 rayon needle punched nonwovens and the PET needle punched nonwovens according to examples 1 and 2 were laminated with a tufted carpet (600 g/m.sup.2 PA), a velour carpet (560 g/m.sup.2 PET) and a flat needle punched nonwoven (300 g/m.sup.2) respectively and measured in the impedance tube. The significantly better absorptive efficiency of the composites with rayon needled nonwovens according to the invention compared to the PET needled nonwoven can be seen in FIGS. 3 to 5.