METHOD FOR THE CONTINUOUS PRODUCTION OF NONWOVEN FABRIC, AND ASSOCIATED NONWOVEN FABRIC PRODUCTION APPARATUS AND NONWOVEN BOARD

Abstract

A method for the production of a continuous nonwoven fabric from fiber mixtures of carrier fibers and binding fibers, comprising the steps: a. Feeding fibers; b. Breaking up, combing and opening out the fibers; c. Mixing the fibers; d. Sucking the fibers between two opposing airpermeable conveyor belts running at identical speed, such that the air is sucked from the outside in the front section of the conveyor belts in such a way that the air flow is always sucked through the deposited nonwoven fabric by air extraction at different times and different locations across the width and parallel to the conveyor belts and the fibers are thereby positioned perpendicular to the surface of the conveyor belts; e. Thermally solidifying the nonwoven fabric created by heating with hot air or shortwave radiation and cooling. Also a nonwoven fabric production apparatus.

Claims

1. A method for the production of a continuous nonwoven fabric from fiber mixtures of carrier fibers and binding fibers, comprising the steps of: a. feeding fibers; b. breaking up / combing and opening the fibers; c. mixing of the fibers; d. sucking in the fibers between two opposing air-permeable conveyor belts running at the identical speed, such that the air in the front section of the conveyor belts is sucked from the outside in such a way that the air flow is always sucked through the deposited nonwoven fabric parallel to the conveyor belts by temporally and locally varying air suction over the width, and thus the fibers are deposited perpendicular to the surfaces of the conveyor belts; e. thermal bonding of the created nonwoven fiber by heating by means of hot air or short-wave radiation and cooling.

2. The nonwoven fabric manufacturing method according to claim 1, wherein the suction power at the opposing, air-permeable conveyor belts (4, 4′) is identical in each case.

3. The nonwoven fabric manufacturing method according to claim 1, wherein the suction power along the conveyor belt is different at the opposing, air-permeable conveyor belts (4, 4′).

4. The nonwoven fabric production method according to claim 1, wherein the suction power and/or the belt speed of the conveyor belts is adjusted over the production cycle according to a predetermined system, whereby a local and temporal variation can be realized.

5. The nonwoven fabric manufacturing method according to claim 1, wherein the belt speed of the conveyor belts and the suction power of the air extraction system are coupled to each other.

6. The nonwoven fabric manufacturing method according to claim 1, wherein the distance between the belts is adjustable.

7. The nonwoven fabric manufacturing method according to claim 1, wherein the heating of the nonwoven is carried out via hot air and/or short-wave radiation.

8. A nonwoven fabric manufacturing apparatus (1) comprising: a supply arrangement (5, 5′) for carrier fibers; a supply arrangement (5, 5′) for binder fibers; at least one opening arrangement or opening/loosening combing arrangement or at least one fiber opener (6, 6′) for combing, separating, loosening and detaching the carrier fibers and/or binder fibers; at least one mixing system (7, 7′) for mixing the loosened or detached fibers; a transport system with air suction (8, 8′) in the front section of the transport system for aligning and depositing the fibers consisting of air guide channels and pressure control nozzles (151 154) and with a heat source (9) in the rear section of the transport system with subsequent cooling source (10) for thermal bonding of the resulting nonwoven fabric, wherein the front section of the transport system with air suction (8, 8′) consists of opposing airpermeable conveyor belts (4, 4′) running at the same speed, and the loosened and mixed fibers are conveyed between the opposing conveyor belts, and the fibers are arranged in different density over the width and length of the nonwoven fabric on the transport belts perpendicular to the conveyor belts due to the air suction (8, 8′) (81 – 810) from the outside.

9. The nonwoven fabric manufacturing apparatus (1) according to claim 8, wherein a conveyor belt (11) for transporting away the nonwoven fiber is arranged downstream of the transport system with air suction (8, 8′) and heat source (9).

10. The nonwoven fabric manufacturing apparatus (1) according to claim 8, wherein a cutting device (12) for dividing the nonwoven fabric into sections / nonwoven fiber sheets or blanks is located on the conveyor belt (11).

11. The nonwoven fabric manufacturing apparatus (1) according to claim 8, wherein threedimensional moldings (14) are arranged downstream of the conveyor belt (11) and the cutting device (12).

12. The nonwoven fabric manufacturing apparatus (1) according to claim 8, wherein the cooling source (10) for thermal bonding and consolidation is arranged downstream of the heat source (9) in the rear section of the transport system or for cooling the content of the threedimensional molded part (14).

13. The nonwoven fabric sheet or board produced by means of a nonwoven fabric production method according to claim 1 wherein the nonwoven fabric sheet has a defined density distribution over the length and the width.

14. The nonwoven fabric sheet or board produced by means of a nonwoven fabric manufacturing apparatus (1) according to claim 8, wherein the nonwoven fabric sheet has a defined density distribution over the length and the width.

Description

[0058] In the following, embodiments of the invention are described in detail with reference to the accompanying drawings in the description of figures, whereby these are intended to explain the invention and are not to be regarded as necessarily limiting:

[0059] It shows:

[0060] FIG. 1 a schematic representation of an embodiment example of the vertical alignment of the fibers between two parallel, air-permeable conveyor belts;

[0061] FIG. 2 a schematic representation of an embodiment of a nonwoven fiberboard;

[0062] FIG. 3 a schematic representation of an embodiment of a nonwoven fiber manufacturing apparatus with separate feed arrangements of carrier fibers and binder fibers, common mixing system and parallel running, air-permeable conveyor belts;

[0063] FIG. 4 a schematic representation of a differentiated air flow and -suction across the width;

[0064] FIG. 5a schematic illustration of an embodiment of the rear section of a nonwoven fiber manufacturing apparatus with parallel air-permeable conveyor belts, a heat source, a cooling source and a cutting device;

[0065] FIG. 6a schematic illustration of an embodiment of the rear section of a nonwoven fiber manufacturing apparatus with parallel air-permeable conveyor belts, a heat source, a cutting device and a three-dimensional molded part;

[0066] FIG. 7 a possible density distribution for a floor insulation of a passenger car;

[0067] FIG. 8 the compression hardness as a function of the soak time;

[0068] FIG. 9 suction of the fibers in two belts running at the same speed in such a way that the fibers are sucked in parallel to the belts;

[0069] FIG. 10 the control of fiber filling at the start of production;

[0070] FIG. 11 the fiber arrangement in the belts during continuous production and

[0071] FIG. 12 the fiber arrangement in the belts with spatially different fiber extraction along the belts in the front area.

[0072] At this point it should be pointed out that functionally identical components are provided with uniform reference signs.

[0073] FIG. 1 shows a schematic representation of an embodiment with vertically oriented fibers 3 between two parallel air-permeable conveyor belts 4, 4′.

[0074] FIG. 2 shows a schematic representation of an embodiment of a nonwoven fiberboard 2 comprising vertically oriented fibers 3.

[0075] FIG. 3 shows a schematic drawing of an embodiment of a nonwoven fiber manufacturing apparatus 1 with separate feed arrangements 5, 5′ of carrier fibers and binder fibers, separate fiber openers 6, 6′, common mixing system 7 and air-permeable conveyor belts 4, 4′ running parallel above and below. The fibers are each fed from the feed arrangement 5, 5′ into a fiber opener 6, 6′. The fiber openers 6, 6′ are followed by a common mixing system 7 for mixing the fibers for homogeneous distribution.

[0076] FIG. 4 shows in front view a schematic representation of an embodiment example of a nonwoven fiber manufacturing apparatus 1 with separate feed arrangements 5, 5′ of carrier fibers and binder fibers, separate fiber openers 6, 6′, common mixing system 7 and air-permeable conveyor belts 4, 4′ running parallel above and below. The fibers are each fed from the feed arrangement 5, 5′ into a fiber opener 6, 6′. The fiber openers 6, 6′ are followed by a common mixing system 7 for mixing the fibers for homogeneous distribution.

[0077] Via a system of several fans 15-1 - 15-4, the air, fiber flow is guided via an air guide channel / a deflection channel 16 into the two parallel, air-permeable conveyor belts 4, 4′.

[0078] Via an air suction unit 8, 8′, 81 - 8.10 from the outside on the air-permeable conveyor belts 4, 4′, suction is applied over the width of the nonwoven fiber with varying strength, also varying over time, and the fibers condense perpendicular to the surface of the conveyor belts in varying density. The start of the air suction 81 - 8.10 is at the beginning of the conveyor belts and the end of the air suction 82 is directly in front of the system area for thermal bonding. For thermal bonding, a heat source 9 and a cooling source 10 are connected in series. The finished nonwoven fabric / fiber web is then further processed in subsequent production steps.

[0079] FIG. 5 shows a schematic representation of the rear section of an embodiment of a nonwoven fiber manufacturing apparatus 1 with air-permeable conveyor belts 4, 4′ running parallel at the top and bottom, a heat source 9, a cooling source 10 and a downstream conveyor belt 11 with cutting device 12. The finished nonwoven fiber boards 2 are collected in a product collection container 13. The end of the air suction 82 is directly in front of the system area for thermal bonding with heat source 9 and cooling source 10.

[0080] FIG. 6 shows a schematic drawing of the rear section of an embodiment of a nonwoven fiber manufacturing apparatus 1 with air-permeable conveyor belts 4, 4′ running parallel at the top and bottom, a heat source 9, a downstream conveyor belt 11 with cutting device 12 and three-dimensional molded parts 14. The lower half of a three-dimensional molded part 14 is moved along under the warm and thus readily moldable nonwoven fabric boards 2. When the conveyor belt 11 ends, the sections are deposited individually on the lower three-dimensional molded part halves. The upper mold part halves are then pressed with a specified pressure onto the lower mold part halves, each filled with a nonwoven fabric board 2, and the nonwoven fiberboard 2 is thus formed. Cooling of the heated nonwoven fabric board 2 formed in the three-dimensional mold parts 14 is performed in the lower halves of the three-dimensional mold parts 14, respectively, before transfer to a product collecting container 13. A finished formed nonwoven fiber product is obtained.

[0081] FIG. 7 shows a possible density distribution for the floor insulation of a passenger car. In the foot installation areas, the density is higher for this example at 70 kg/m.sup.3, in the tunnel and under the seats at 30 kg/ m.sup.3.

[0082] FIG. 8 the compression hardness as a function of the soak time.

[0083] FIG. 9 shows the suction of the fibers in two conveyor belts running at the same speed in such a way that the fibers are sucked in parallel to the belts.

[0084] Further, FIG. 10 shows the control of fiber filling at the start of production and FIG. 11 shows the fiber arrangement in the belts during continuous production.

[0085] FIG. 12 shows the arrangement of the suction with spatially different suction along the belts at the top and bottom and the arrangement of the fibers in the belts.

TABLE-US-00001 List of reference signs 1 nonwoven fabric manufacturing apparatus 2 nonwoven fabric board 3 perpendicular oriented fibers 4, 4′ air permeable conveyor belt 5, 5′ supply arrangement 6, 6′ fiber opener 7, 7′ mixing system 8, 8′ air suction 8-1 - 8-10 81 start air suction 82 end air suction 9 heat source 10 cooling source 11 conveyor belt 12 cutting device 13 product collection container 14 three-dimensional molded part 15-1 - 15 -4 fans for controlling the air and pressure control nozzles 16 air guide channels