Needled sandwich nonwoven fabric structure and method of manufacturing same

Abstract

The present invention relates to needled sandwich material structures in which a core nonwoven having vertically oriented fibers is used, and to methods for making these sandwich material structures.

Description

[Technical Field]

[0001] The present invention relates to needled sandwich material structures in which a core web with vertically oriented fibers is used, and to methods for making these sandwich material structures. [Background technology]

[0002] In the prior art, German Patent Application Publication No. 102016203348 reports on a multilayer sound-absorbing and / or reinforcing nonwoven fabric. Unpublished German Patent Application No. 102019104847 discloses the needling of scattering material onto a needled nonwoven structure. Unpublished German Patent Application No. 102019104851 discloses a device for spreading scattering material onto a needled nonwoven structure.

[0003] German Patent Application Publication No. 2032624 describes a fiber layer material, particularly suitable for artificial leather, formed from two fiber layers arranged one above the other and differing in the arrangement of the fibers that make up the layers. The fiber layer material comprises a first fiber layer (short fiber layer) constructed of fibers that extend essentially in the thickness direction and one or more second fiber layers in which the fibers extend predominantly in the surface direction. The two fiber layers are superimposed and bonded to each other in a stacked configuration, with the fibers located in the surface region of the first fiber layer intertwined with the fiber structure of the second fiber layer. The fiber layer material preferably comprises a polymeric elastic material. The short fiber layer, whose fibers extend essentially in the thickness direction, is produced by cutting a fiber tape produced on a Rando-Webber or cross-laying machine into continuous fiber strips in the thickness direction in a cutting station, which then rotates the fiber strips 90° in a rotating station. Fiber taps are then fed on both sides, and the layer structure is pressed and needled. The composite is then cut at the center of the short fiber layer, and then impregnated with a polymeric elastic material and subjected to a buffing process. The fibers used have an island structure. After impregnation, the layer composite is treated with a solvent to remove the embedded components, and then dried. Thus, a fiber layer material similar to synthetic leather is finally obtained.

[0004] German Utility Model No. 29812401 discloses a fiber composite material for self-supporting molded parts with high surface stability, in which a Struto nonwoven fabric is laminated on both sides with a further nonwoven fabric. Tao Yang et al., "Investigation on Acoustic Behavior and Air Permeability of Struto Nonwoven; Fibers and Polymers 2016, Vol. 17, No. 12, pp. 2078-2084," describes the sound absorption performance of Struto nonwoven fabrics and their breathability.

[0005] WO 02 / 20889, WO 2005 / 081226, WO 2009 / 140713 and WO 2010 / 042993 generally describe absorbent material structures with vertical fibre orientation and their manufacture.

[0006] Vertical fiber orientation is also used as an insert, in particular for seats / seat cushions, see for example WO 2012 / 019752 and WO 2020 / 072412.

[0007] DE 112012005205 ​​A1 (see also WO 2013 / 088828 A1, US 2014 / 0302285 A1, US 9321412 A1) discloses the application of vertical fiber orientation in the insulation of floor panels in the automotive industry, and US 2017 / 0008462 A1 in particular describes the use as a partial damping element in this context. Summary of the Invention

[0008] Therefore, compared with the aforementioned prior art, an object of the present invention is to provide a microperforated needle-punched sandwich nonwoven structure made from a core nonwoven with vertical fiber orientation, where scattering material is applied between the vertically oriented fibers due to the application and / or properties, and the core nonwoven is needle-punched on one or both sides with a nonwoven, woven, knitted, paper, or film. Furthermore, an object of the present invention is to provide a method for the in-line production of such a nonwoven structure.

[0009] In a first embodiment, the subject of the present invention is a microperforated needled sandwich nonwoven structure 1 having a core nonwoven 2 with vertical fiber orientation, comprising PET and / or PET / PP fibers and bonding fibers of PE, PP and / or BiCo fibers (coPET), the core nonwoven 2 being provided on one or both sides with a cover material 3a, 3b, the areas between the vertically oriented fibers of the core fleece 2 contain the same or different filler material 4 interspersed with ground material, fibers, flakes and / or powder, The cover materials 3a, 3b may be the same or different and may each independently comprise a nonwoven fabric, a woven fabric, a knitted fabric, paper or a film; The object of the present invention is to provide a micro-perforated needle sandwich nonwoven fabric structure 1 characterized by the above-mentioned. [Brief explanation of the drawings]

[0010] [Figure 1] 1 shows an apparatus for producing a microperforated needle-punched sandwich nonwoven structure 1 according to the present invention and its basic manufacturing process. [Figure 2] 2 shows a variant of the device according to FIG. 1; [Figure 3] A process variant with two roller pairs 12, 13 is described. DETAILED DESCRIPTION OF THE INVENTION

[0011] FIG. 1 shows an apparatus for producing a microperforated needle-punched sandwich nonwoven structure 1 according to the present invention and its basic manufacturing process. A mechanically or pneumatically produced nonwoven fabric 6 is fed into a vertical lay-up device 7, where the fibers are laid at an angle of approximately 90° to 45°. The "vertically laid" fibers are then fed in-line to a scattering device 8, which adds a filler material 4 to the fibers held between them. The resulting preform is then fed into an oven 9, where the structure is thermally cured. The resulting composite is then provided with a covering material 3a, 3b on one or both sides. In a subsequent needling unit 10, the entire composite is needled to form the final product 1. FIG. 1 also shows a preferred embodiment in which, in addition to the cover material 3a, 3b, an additional film 5 is provided on one side between the core nonwoven fabric 2 and the cover material 3a, 3b. If sound absorption or mechanical properties are affected, a film 5 can additionally be provided between the cover material 3a, 3b and the core fleece (2). If the cover material 3a, 3b comprises a film, the additional film 5 is omitted.

[0012] Figure 2 shows a variant of the apparatus according to Figure 1. After passing through the scattering device 8, the nonwoven fabric obtained from the vertical lay-up device 7 is fed to a roller pair 11 and compressed and spread accordingly. Alternatively, Figure 3 describes a process variant with two roller pairs 12, 13, roller pair 12 being arranged upstream of the scattering device 8 and roller pair 13 being arranged downstream of the scattering device.

[0013] The prior art is not aware of a nonwoven structure having vertical fiber orientation based on mechanical or aerodynamic nonwoven formation with needled cover webs, films, or papers on one or both sides. Furthermore, there is no disclosure of interspersing different scattering materials between the vertical fiber orientations. Processes and plants for producing such nonwoven structures are also not known.

[0014] In addition to covering one side of the core nonwoven fabric 2, it is also preferable to cover both sides with the aforementioned cover materials 3a and 3b, which may be the same or different and may have different materials, thicknesses, densities, flow resistances (breathability), etc.

[0015] In a further embodiment, a film 5 is additionally positioned on one or both sides between the core nonwoven 2 with vertical fiber orientation and the cover material 3a, 3b, and the entire composite is also microperforated by needling. Film materials include, in particular, PE / PA / PE and PA / PE. Pure PE films are also used. The film 5 has a thickness essentially in the range of 40 μm to 180 μm. If only one film fleece (PE / PA / PE+PET) is used as the cover material (3a, b), a thickness of up to 450 μm is preferred. The weight per unit area of ​​the nonwovens 3a, 3b is 60 to 450 g / m. 2 It is preferable that the range is:

[0016] A method according to the invention for the production of a microperforated needle-punched sandwich nonwoven structure 1 (see FIG. 1 ) comprises feeding cover materials 3 a, 3 b in-line to a core nonwoven 2 with vertical fiber orientation on at least one side, allowing the entire composite to be needle-punched, The fibers of the mechanically or aerodynamically formed nonwoven fabric 6 are oriented in a vertical lay-up device 7 primarily in the range of 90° to 45°; Spreading the oriented fiber / fiber layer, The scattering device 8 scatters the filler material 4 between the vertically oriented fibers; The resulting structure is heat cured in an oven 9, After solidification, cover materials 3a, 3b are applied to one or both sides, The obtained composite is needled in a needling unit 10. It is characterized by:

[0017] It is advantageous if the furnace 9 is equipped with two conveyor belts and two separate drives. By using different speeds for the upper and lower belts, the tightness of the oriented fibers / fiber layers can be adjusted independently of each other.

[0018] Furthermore, it is advantageous to be able to set different temperatures (top and bottom) in the oven, preferably in the range of 120-180°C, for example by means of special hot air slot nozzles transverse to the throughput direction, which can be controlled separately as required. It is therefore advantageous to be able to influence the properties of the fiber / scattering composite, especially via its thickness.

[0019] The focus here is primarily on the cross-linking of the material, i.e. the influence on the mechanical properties stiffness, strength and processing behavior in subsequent processes.

[0020] The spreading of the fibers / fiber layers oriented at 45° from the vertical direction (90°) is achieved, for example, by placing a roller pair 11 behind the scattering device 8, i.e. between the scattering device 8 and the furnace 9 (see FIG. 2), in the direction of movement. The speed of the roller pair 11 can be variably adjusted and can be greater than the operating speed of the vertical lay-up device 7.

[0021] It is also possible to work with two roller pairs 12, 13: one roller pair 12 is arranged upstream of the scattering device 8 and one roller pair 13 is arranged downstream of the scattering device (upstream of the furnace 9) (see FIG. 3). Both roller pairs 12 and 13 can be controlled separately.

[0022] An essential element of the present invention is a finely perforated needle-punched sandwich nonwoven structure whose sound absorption, mechanical and processing properties are achieved, on the one hand, by scattering a scattering material that influences these properties into the vertically oriented fibers, and, on the other hand, by a process of needle-punching one or both sides of this structure with a nonwoven, woven, knitted fabric, paper or film. Furthermore, the in-line process for producing such sandwich nonwoven structures, in particular by means of an integrated scattering plant, and precisely the scattering of the scattering material into the vertical fiber orientation, represents a novelty in the plant field.

[0023] The advantages of the present invention lie in particular in the in-line production of micro-perforated needle-punched sandwich nonwoven structures with vertical fiber orientation (in the core), where on the one hand the sound absorption, mechanical and processing properties (and therefore ultimately the part properties) of the nonwoven can be influenced by the fiber orientation, fiber mix, fiber fineness of the core nonwoven and the scattering material contained in the core nonwoven, and on the other hand, by needling this scattering-filled core nonwoven formed with vertically oriented fibers with nonwovens, wovens, knits, paper or films, new and well-optimized sandwich nonwoven structures are provided.

[0024] In particular, the following materials are used as scattering materials between the vertically oriented fibers of a core nonwoven fabric with vertical fiber orientation, which affects the following properties: Sound absorption: hollow fibers with different cross-sectional shapes, GF / BiCo / PET crushed / fiber materials, foam flakes; Water absorption: Hydrophobized fibers (especially H-PET), GF / PP / BiCo milled / fiber materials; Stone chipping: PP / PE crushed / fibrous materials; Ice accumulation / adhesion: Hydrophobized fibers (especially H-PET), PP / PET crushed materials; Stiffness: carbon fiber, natural fiber; Heat-resistant: PP / GF crushed / fiber material, mineral fiber, glass fiber (GF); Combustion behavior: GF / Panox / PET / BiCo crushed / fiber materials, flame retardants, flame retardant treated fibers, mineral fibers, glass fibers; Tear resistance: Aramid fiber.

[0025] The sandwich nonwoven structure according to the invention is microperforated by needling, microperforation in the sense of the invention being defined by a pore size in the range of 0.05 to 2.4 mm.

[0026] Execution example: Example 1: According to the method of the present invention, a commercially available 500 g / m 2 PET fiber with vertically oriented fibers (65% PET / 35% coPET) was 2 Nonwoven fabric 2, 50 g / m 2 75% PP / 25% PE crushed / fiber material 4 is scattered on both sides, and this is 80 g / m 2 Needle-processed nonwoven fabric (75% PET / 25% PP)3.

[0027] After molding into wheel arch liners, conventional nonwoven fabrics (800 g / m 2 Comparative tests were carried out with a conventional wheel arch liner made of 40% PP / 30% PET / 30% BiCo. Significant differences were observed in terms of bending stiffness (10% increase), stone impact resistance (penetration and weight loss) and deformation behavior.

[0028] Example 2: According to the method of the present invention, 1300g / m 2 Nonwoven fabric with vertically oriented fibers (70% PET / 30% coPET) 2,100 g / m 2 40% PP / 30% PET / 30% BiCo ground material 4 is interspersed, followed by 150 g / m 2 A needled nonwoven fabric (75% PET / 25% PP)3 was needle-punched on both sides. Again, significant improvements in mechanical properties were observed after forming into an underbody shield compared to conventional underbody shield material structures. [Explanation of symbols]

[0029] 1. Sandwich nonwoven structure 2. Core nonwoven fabric 3a, 3b Cover material 4 Filling material 5 Film 6. Nonwoven fabric 7 Vertical Layup Device 8 Scattering Devices 9 Furnace 10 Needle processing section 11 Laura Vs. 12 Laura Vs. 13 Laura Vs.

Claims

1. The nonwoven fabric (2) has a vertical fiber orientation and comprises PET and / or PET / PP fibers and bonding fibers of PE, PP and / or BiCo fibers (coPET), and the core nonwoven fabric (2) is provided on one or both sides with a cover material (3a, 3b), The regions between the vertically oriented fibers of the core nonwoven (2) contain the same or different filler material (4) sprinkled with ground material, fibers, flakes and / or powder, The cover materials (3a, 3b) may be the same or different and each independently comprise a nonwoven, woven, knitted fabric, paper or film. Microperforated needle-punched sandwich nonwoven structure (1).

2. 2. The sandwich nonwoven structure (1) according to claim 1, comprising a film (5) between the core nonwoven (2) and the cover material (3a, 3b).

3. The fibers of the mechanically or aerodynamically formed nonwoven fabric (6) are in-line oriented in a vertical lay-up device (7) primarily in the range of 90° to 45°; Spreading the oriented fiber / fiber layer, A spreading device (8) spreads the filler material (4) between the vertically oriented fibers; The resulting structure is heat cured in an oven (9), After solidification, a cover material (3a, 3b) is applied to one or both sides, The obtained composite is needled in a needling unit (10). A method for producing a sandwich nonwoven structure (1) according to claim 1 or 2.

4. The vertically oriented fibers of the core nonwoven fabric (2) are spread by the roller pair (11, 12, 13), and the roller pair (11, 12, 13) (a) before (12) and after (13) the dispensing device (8), or (b) arranged to pass through a pair of rollers (11) after said spreading device (8); The roller pairs (11, 12, 13) can be individually controlled as needed. The method of claim 3.

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