Absorptive Schallisolation

Abstract

Absorptive sound insulation for the vehicle interior and luggage compartment (a) a wear layer and (b) a stiffening nonwoven laminated underneath containing rayon made of solid individual phases with a multi-limbed cross-sectional shape with at least three limbs, in which the limbs 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, wherein the stiffening nonwoven is produced by a fiber flocking process, and the fiber mixture used for sound insulation comprises 25 wt.% BiCo, 20 wt.% PET with good crimp and 55 wt.% rayon, and further where the wear layer (a1) a tufted carpet, in particular with the yarn materials PA 6.6, PP, rPA and PET, rPET and the corresponding bio-based polyamides (PA 5.10; PA 6.10), (a2) a velour and flat needle felt carpet, in particular with the fibre materials PET, PET / PP, PP, PA / PET and rPET, (a3) a microperforated film or (a4) comprises a PET or mixed fibre nonwoven.

Description

The invention relates to absorptive sound insulations for the interior of a motor vehicle and luggage compartment of a motor vehicle with absorption / stiffening fleeces or 3D absorbers, which partially or completely comprise staple wool.Viscose fibers, called viscose or staple viscose for short, comprise chemical fibers (regenerated fibers) which are industrially produced starting from the basic material cellulose with the aid of the viscose process. For example, sawdust is cooked with chemicals to dissolve out the cellulose. The cellulose is then processed with water, sodium hydroxide solution and carbon disulfide to form a viscose paste and consolidated by spinnerets to form viscose yarn.The chemical composition of the viscose fibers (basic constituent cellulose) is similar to that of cotton, including their typical fiber fineness (about 10 to 15 μm diameter) and fiber length (about to 40 mm).The use of viscose is similar to that of cotton (textiles, blends with polyester, etc.). Textiles made from this are made into clothing. Examples of applications are, for example, pads, wet wipes, cotton swabs, cleaning wipes and sponge wipes. Such products made of viscose have a high water absorption capacity. Viscose fibers form about 11% of the synthetic fiber production.The starting material for viscose fibers is cellulose, which in turn originates from wood from beech, spruce, eucalyptus, pine, bamboo or the like. The pulp quality used differs from the paper pulp quality in that the chain length of the cellulose molecules is shorter and the purity is higher. The viscose production pulp contains less residual lignin and less hemicelluloses and pentosans, respectively. It has a better reactivity towards sodium hydroxide solution and carbon disulfide and a better solubility in sodium hydroxide solution after the xanthogenation reaction has taken place.For the production of a spinning dope for the spinning of the viscose fibers, the cellulose is first mixed with sodium hydroxide solution in the classic viscose process. The cellulose swells in the aqueous sodium hydroxide solution (mercerization). Carbon disulfide is allowed to act on these. This produces sodium xanthate (xanthate). The orange-yellow xanthate forms a viscous solution in aqueous dilute sodium hydroxide solution. This mass is the viscose dope. After two or three filtrations, ripening and venting, this spinning composition then has the viscosity suitable for reprecipitating the cellulose as viscose filaments. For this purpose, this alkaline solution is forced through nozzles in sulfuric acid salt solutions.For the viscose fibers in the classic production process, a sulfuric acid spinning bath is used which additionally still contains sodium sulfate almost to the saturation limit and a small amount of zinc sulfate for delaying the cellulose precipitation reaction.Various embodiments of sound insulation are known in the prior art, which have acoustic and / or stiffening nonwoven fabrics underneath the usable layer (visible surface); the nonwoven compositions of which are different. Carpet surface products are widely used as the wear layer, namely in particular tufting, velours and flat needle punch fleece carpets.US 2017 / 0 369 005 A1 discloses a silencer for motor vehicles. The silencer is manufactured by press forming. The silencer has a first shaped surface and a second shaped surface opposing each other in a thickness direction. The silencer comprises at least a first fiber layer on which the first shaped surface is formed and a second fiber layer integrated with a surface opposite the first shaped surface, the opposite surface being located on the first fiber layer. Fibers of the second fiber layer are partially located on the opposite surface of the first fiber layer.DE 10 2010 050 336 A1 describes that components with a carpet surface are required for the fitting of interior spaces, luggage spaces and comparable motor vehicle areas, which components combine a good sound absorption with a low weight and a good cobiliance. Materials of the same type should preferably be used. For this purpose, a layer composite for acoustically effective lining of a motor vehicle area is proposed, having a cut pile carpet layer (1) which can be produced by a tufting method and comprises a textile carrier (2) and thereby pile threads (3) running in loops. It should be emphasized that the pile threads (3) of the cut pile carpet layer (4) predominantly consist of fibers selected from fibers having a sectionally concave-contoured cross section, hollow fibers and a fiber mixture with fibers having a sectionally concave-contoured cross section and hollow fibers.JP S50-67 639 A discloses a diaphragm for speakers formed by mixing internal loss fibers and hollow having a large specific elastic modulus in the produced resin.DE 103 24 257 B3 shows that the sound-absorbing material consists of two interconnected nonwoven textile fabrics made of natural and / or synthetic fibers with a thermoplastic and / or thermosetting compound. The nonwoven fabric toward the sound source has a thickness of 2-15 mm, a density of 50-500 kg / m 3 and a weight of 0.1-5.0 kg / m 2 at a flow resistance of 50-1000 kNs / m 4. The nonwoven fabric remote from the sound source has a thickness of 10-100 mm, a density of 20-200 kg / m 3, a weight of 0.5-1.0 kg / m 2 and a flow resistance of 10-40 kNs / m 4. The composite material has a total thickness of 12-30 mm and a weight of 0.5-3.0 kg / m 2.DE 10 2018 114 125 A1 relates to a method and an apparatus for producing shaped textile multilayer composites. More particularly, the invention relates to a method in which a multilayer textile composite is laid and laminated and stretched and then formed into an upper of a floor covering in the automobile sector, with the proviso of saving material and reducing cycle time.DE 10 2012 222 000 A1 relates to a method for producing at least two-layer components and correspondingly produced components per se as an absorbent cladding in the interior and / or trunk or for floor coverings of motor vehicles, comprising an outer material and an absorber.DE 20 2012 004 594 U1 shows a motor vehicle part for a motor vehicle, characterized in that the useful layer consists of polyethylene terephthalate (PET) yarns and / or fibers, (b) an optionally present carrier layer consists of polyethylene terephthalate and / or a copolymeric polyethylene terephthalate, (c) an optionally present first adhesive layer consists of an adhesive based on polyethylene terephthalate, (d) the adhesive layer (middle layer) consists of an adhesive based on polyethylene terephthalate, (e) the backing layer consists of a nonwoven fabric or woven fabric based on polyethylene terephthalate, and (f) the insulation layer consists of PET / coPET fibers.DE 10 2005 053 946 B3 shows a component which has a two-dimensional, mat-like nonwoven fabric with opposite surfaces. A thin spray coating is sprayed onto one of the surfaces of the component and is made of a thermosetting material, e.g., polyurethane and thermoplastic. The thin spray coating has a basis weight of 50 to 1200 grams per square meter and the thickness of the web component is between 5 and 30 millimeters. An independent claim is also included for a method for producing a component for sound insulation in a motor vehicle.EP 3 409 468 A1 describes a shaped flooring system for sound attenuation of a motor vehicle comprising a surface layer, a thermoplastic elastomeric base layer having a density of at least 0.5 kg / m3and a decoupling layer, characterised in that the cover layer comprises an adhesive layer bonded to the surface of the base layer and an adhesive pile of tufts of fibres which is substantially upright in the adhesive and forms the surface cover.US 2020 / 0 002 847 A1 describes staple fibers and filament yarns of cellulose esters, such as cellulose acetate, together with processes for producing the fibers and their use in nonwovens and articles. The filament yarns and fibers described herein can be provided with at least one coating, and in some cases with two or more coatings selected to improve the properties of the fibers. The staple fibers described herein can be used to produce nonwoven fabrics that are strong, soft, absorbent, and biodegradable, and can be used in wet or dry nonwoven articles for a variety of personal care, medical, industrial, and commercial applications.WO 2017 / 114 808 A1 describes an auto carpet having a needle punched structure which can have a low weight but good abrasion resistance. According to embodiments of the present invention, the auto carpet comprises at least one needle punched cover layer as the uppermost layer of staple fibers, wherein the staple fibers comprise at least 50% by weight of solid multilobal fibers, and at least one partial bond. A method for producing this auto-carpet is described, comprising the steps of: transporting a fibrous card web to a cross-laying machine and cross-laying the card web into a nonwoven, wherein the travel distance of the multilobal nonwoven cross-layer is less than 20% and more than 10% greater than the final width of the needle-punched nonwoven cover layer.Below the useful layer there are also adhesive layers, acoustic / stiffening nonwovens, sealing and heavy foils and also contact / foil nonwovens. The coating, usually as an adhesive layer for sub-fleeces, but also for stiffening, comprises in particular thermoplastics, predominantly PE or PP.The sublayers, such as acoustic and / or stiffening nonwovens, generally consist predominantly of PET and mixed-fiber nonwovens, often having a BiCo fiber content (BiCo=bicomponents). Thermoplastic films, in particular PE / PA and PE / PA / PE films and film nonwovens PE / PA / PE+PET, are likewise used as sealing or insulating films. PE / PA is a film material which contains both polyethylene (PE) as the first layer and polyamide (PA) as the second layer. Depending on the acoustic requirements, so-called heavy foils are also used partially or over the entire surface as insulating foils.Between the upper fabric (usable layer plus lower layers) and the vehicle body floor there is usually also an insulation layer which can be formed in particular from PUR foam or else from nonwoven structures (nonwovens or fiber-flock (HMP) composites). If a foam is used, it is generally firmly connected (foamed) to the upper fabric. Nonwoven / fiber flock structures can likewise be firmly connected to the upper fabric, these then generally being bonded together. However, a pure overlaying without a solid compound is also used.In particular in the case of VANs, SUVs, pickups and lightweight commercial vehicles, rubber, PUR-RIM, PVC and increasingly TPO are also used as the usable layer in the prior art.In motor vehicles, thermoformable acoustic and / or stiffening nonwoven fabrics are used, in particular, in the passenger compartment and luggage compartment. These are usually loosely pressed, thermally or thermoplastically bonded nonwoven textile fabrics and combinations of foam and / or nonwoven layers with identical or different flow resistances. In addition, so-called flow fleeces are also used to tune acoustics in a targeted manner.In order to influence the sound absorption capacity in correlation with the walking stiffness, porous layers which are open to air and thus sound are inserted in floor coverings between the actual upper fabric (usable layer) and the process-dependent sealing and heavy layers or the insulation. The porous layers which are open to air and thus sound used here are polyester and mixed fibre fleeces, and also microperforated films. The impact strength is also influenced by the content of bicomponent fibers (BiCo) in the nonwoven fabrics.In known floor covering insulations produced by the fiber-flock process, the fiber mixture consists predominantly of BiCo and PET fibers, as well as breaking cotton and PU foam flocks.Nonwoven applications in end wall material structures often relate to single layer nonwoven fabrics, multilayer nonwoven fabrics and back-foamed nonwoven fabrics. In the case of side claddings, tailgate claddings, wheel arch covers, luggage compartment covers and spare wheel depressions predominantly, non-woven fabrics and / or non-woven fabric combinations are also used in the luggage compartment.EP 0 301 874 B1 relates to regenerated cellulose filaments, in particular viscose filaments having a multi-membered (multi-limbed) cross section, to fibers comprising such filaments and products formed therefrom. An advantage of multi-link viscose filaments over conventional viscose filaments of circular cross section is their greater mass, since the circumferential surface of the multi-link filaments is larger than their actual cross-sectional area.A further advantage of multi-membered viscose filaments is their increased absorbency compared to conventional filaments. In the automobile sector, however, this is a disadvantage if the corresponding components are intended to dry again after wetting with water.EP 0 301 874 B1 provides a solid filament of regenerated cellulose material having a fiber fineness of less than 5.0 dtex and a multi-link cross-section, each link having an aspect ratio of length to width of at least 2:1. The aspect ratio of length to width of the filament members is generally 2:1 to 10:1, preferably 2:1 to 7:1, and more preferably 3:1 to 5:1. This results in a high degree of absorbency when the filaments are in staple form, provided the strands are not so long and thin that they flex back upon themselves. The filament described herein preferably has 3 or 4 limbs, although it may have more than 4 limbs if desired, and also preferably has a cross-sectional shape which is generally (i.e., substantially) symmetrical about at least one axis, as in a Y, X, H or T-shaped filament cross-section, although other shapes are also included within the scope of the invention. Preferably, the filament has a Y-shaped cross-section. The angle between the limbs varies depending on the cross-sectional shape and may be, for example, 5 to 180°, although it is preferred that the filament cross-section be as regular as possible.The filament described herein has a low fiber fineness (individual denier) of less than 5.0 dtex, with a lower fiber fineness being advantageous for products with high absorbency. Generally, the fiber fineness is between 0.5 and 5.0 dtex, but more preferably between 1.5 and 4.0 dtex. The filaments are advantageously produced in the form of staple fibers. The combination of the multi-link cross-sectional shape and the low fiber fineness gives filaments having high absorbency in staple fiber form. In addition, the fiber has a high mass, cotton-like hand and tenacity approximately corresponding to conventional circular cross-section viscose filaments for a given viscose composition and fiber fineness.The staple fiber preferably comprises multi-strand filaments, all of which have substantially the same cross-sectional shape. This allows easier control of the fibre properties such as absorbency and mass. However, if desired, the staple fiber may comprise a mixture of filaments having two or more different cross-sectional shapes, provided that at least some of the filaments have a multi-membered cross-section characteristic of the filaments described herein. Preferably, the filaments are viscose and are suitably spun from a standard viscose composition using standard viscose spinning conditions, except that the conventional circular holes are replaced with multi-link shaped extrusion holes in the spinneret. Because the filaments produced have a rigid rather than a hollow structure, the disadvantages associated with the production of hollow filaments are avoided.After spinning, the filaments are stretched and then preferably cut into staple lengths, washed and dried using conventional techniques to give staple fibers.Products formed from the fiber can contain exclusively the aforementioned fibers, i.e. consist of these, or be mixed with other fibers, i.e. contain these. These other fibers can be, for example, cellulose fibers such as standard viscose or cotton or non-cellulose fibers such as polyester. In addition, the aforesaid fiber may be incorporated into a product in only one cross-sectional shape, for example, only Y-shaped, or alternatively two or more different cross-sectional shapes may be used.The object of the present invention compared with the aforementioned prior art is thus the use of the aforementioned fibers in sound insulations for the interior and luggage compartment of the motor vehicle and thus the overcoming of the disadvantages known from the prior artThe present invention relates according to the invention to a sound insulation for the interior and luggage compartment of a motor vehicle comprising (a) a usable layer and (b) an absorption / stiffening nonwoven laminated underneath and containing staple wool of solid individual phases having a multi-limb cross-sectional shape with at least three limbs, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2:1 and the individual titer is 0.5 to 5 dtex.While the prior art relating to the above-mentioned fibers has substantially dealt with absorbency, the present invention is first of all directed to sound insulation using said fibers in a specific field of vehicle acoustics, here the interior and luggage compartment of the motor vehicle. Thus, in the context of the present invention, front wall inside, floor cladding, including. The roof lining may be provided with insulation, roof lining, rear parcel shelf, side lining of the luggage compartment, cover for the wheel house on the inside, spare wheel recess, cover for the luggage compartment and load floor.The prior art does not disclose sound insulations which partly or completely contain staple wool from solid single phases having a multi-limb cross-sectional shape, wherein at least three limbs are present in which the limbs of the cross-sectional profile each have a length / width ratio of greater than 2:1 and the individual titer is 0.5-5 dtex.According to the invention, the absorbent / stiffening nonwoven consists entirely of staple wool of solid individual phases having a multi-limb cross-sectional shape with at least three limbs, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2:1 and the individual titer is 0.5 to 5 dtex.Not according to the invention, a microperforated PA / PE film (for example 65 μm, 50 μm PA / 15 μm PE, hole diameter 0.12 mm) was laminated with a nonwoven, for example consisting of 25% by weight of commercially available BiCo fibers [co-PET] and 75% by weight of staple wool made of solid individual phases having a multi-limb cross-sectional shape, wherein at least three limbs are present, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2 to 1 and the individual titer is 0.5 to 5 dtex.Furthermore, not according to the invention, 35 wt % BiCo and 65 wt % staple wool of solid single phases with multi-limb cross-sectional shape are used in the case of the use of a fiber mixture, wherein at least three limbs are present, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2:1 and the single titer is 0.5 to 5 dtex; from which a 3D floor cladding insulation was produced in the per se known fiber-flock method.The fiber mixture according to the invention for acoustic insulations, produced by the fiber-flock method, comprises, for example, 25% by weight of BiCo, 20% by weight of PET with smooth crimp and 55% by weight of staple wool made of solid single phases with multi-limb cross-sectional shape, wherein at least three limbs are present, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2:1 and the individual titer is 0.5 to 5 dtex.This in turn can be laminated with a conventional wear layer made of tufting, velours or flat needle-punched non-woven carpet.Intermediate layers, acoustic / stiffening fleeces and PE / PA / PE films (closed or microperforated) are often used.Essential elements of the present invention are sound insulation structures in which the acoustic, mechanical and processing properties make it possible to optimize / tune on a demand-related basis by a targeted formulation of the fiber mixture with staple wool from solid single phases having a multi-limb cross-sectional shape, wherein at least three limbs are present, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2:1 and the individual titer is 0.5 to 5 dtex.A further preferred embodiment of the present invention relates to an absorptive sound insulation as defined above, which comprises a 3D sound insulation geometry produced by the fiber-flock method (HMP technology).The material of the wear layer can serve various applications in the motor vehicle. According to the invention, the usable layer comprises(a1) a tufting carpet, in particular with the yarn materials PA6.6, PA6, PP, rPA and PET, rPET and the corresponding bio-based polyamides (PA 5.10; PA 6.10)(a2) a velour and flat needle-punched non-woven carpet, in particular with the fibre materials PET, PET / PP, PP, PA / PET and rPET,(a3) a microperforated film, or(a4) a PET or mixed fiber nonwoven.The advantage of the present invention consists in particular in the provision of deformable / stable nonwoven layers containing or consisting of staple viscose from solid single phases having a multi-limb cross-sectional shape, wherein at least three limbs are present, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2:1 and the individual titer is 0.5 to 5 dtex; which are integrated into the material structure of sound insulations; and in the fiber mixture of 3D absorbers having partly or completely staple viscose from solid single phases having a multi-limb cross-sectional shape, wherein at least three limbs are present, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2:1 and the individual titer is 0.5 to 5 dtex; This invention is based on the fiber-flock process, and thus new, property-optimized sound insulations can be provided.Exemplary Embodiment:Example 1:To demonstrate the acoustic effectiveness, a 400 g / m 2 and a 600 g / m 2 needle-punched nonwoven made from commercial staple viscose [GALAXY® VY fiber from Kelheim Fibers GmbH] made from solid individual phases having a multi-limb cross-sectional shape, wherein at least three limbs are present, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2:1 and the individual titer is 0.5 to 5 dtex, were produced in a manner known per se.Example 2:Furthermore, in each case a 400 g / m 2( VEGRO 400) and a 600 g / m 2( VEGRO 600) needle-punched fleece were produced from 30 wt % PET (12 dtex / length 64 mm), 30 wt % PET (11 dtex / length 60 mm) and 40 wt % PET (6.7 dtex / length 64 mm).The absorption measurements performed in a conventional alpha cabin are shown in Figure 1.FIG. 2 shows measurement results pressed / uncompressed, measured in the impedance tube.The figures clearly show the absorptive effectiveness of the sound insulations according to the invention.Example 3: Example 3:In application for floor and trunk coverings, the 600 g / m 2 spun bond needle webs and the PET needle webs of Examples 1 and 2 were each laminated with a tufting carpet (600 g / m 2 PA), a velour carpet (560 g / m 2 PET) and a flat needle web (300 g / m 2) and each measured in the impedance tube. The clearly better absorptive activity of the composites according to the invention with nonwoven cell wool needles compared to the nonwoven PET needle is shown in FIGS. 3 to 5.

Claims

Absorptive sound insulation for the interior and luggage compartment of a motor vehicle comprising (a) a usable layer and (b) a stiffening fleece laminated underneath, containing staple viscose from solid single phases with a multi-limb cross-sectional shape with at least three limbs, in which the limbs of the cross-sectional profile each have a length / width ratio of at least 2:1 and the individual titer is 0.5 to 5 dtex, wherein the stiffening fleece is produced by a fiber-flock process, and the fiber mixture used for sound insulation comprises 25 wt.% BiCo, 20 wt.% PET with good crimp and 55 wt.% staple viscose, and further wherein the usable layer (a1) comprises a tufting carpet, in particular with the yarn materials, PA 6.6, PP, rPA and PET, rPET and the corresponding bio-based polyamides (PA 5.10; PA 6.10), (a2) comprise a velour and flat needle-punched non-woven carpet, in particular with the fibre materials PET, PET / PP, PP, PA / PET and rPET, (a3) a microperforated film or (a4) a PET or mixed fibre non-woven.

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