WO1994002673A1 - Process and apparatus for dynamic-flow production of ductile, highly tear-resistant fiber mats - Google Patents

Abstract

Disclosed is a process for dynamic-flow production of ductile, highly tear-resistant fiber mats from a fibrous web consisting of cellulose fibers impregnated with a binder and thermoplastic fibers and/or natural, vegetable fibers, where the apparatus, arranged in the flow direction of the material, consists of a web forming machine (1), a pair of press rollers (3, 4), a pair of draw-in rollers (5), a cylinder (6), an air channel (10) which is fed by ventilators (12) and fitted with one or more control members (25) in the form of one or more adjustable flaps, a venturi rod (7), a diffuser (13), a mat forming roll (15), feed rollers (16, 17), a surface weight measuring device (19), a needle machine (20), a flattening device (21), a cutting machine (22) and a stacking device (24). Disclosed also is the use of a ductile, highly tear-resistant fiber mat produced by the process as per the invention, where one or more of the fiber mats (23, 23') is used for producing form pieces by pressing at elevated pressure and temperature.

Description

 Process for the fluid dynamic production of foamable fiber mats with high tear strength and device for their production

Technical field

The invention relates to a process for the fluid dynamic manufacture of deformable fiber mats of high tensile strength from a nonwoven fabric, consisting of cellulose fibers and thermoplastic fibers and / or natural fibers of vegetable origin impregnated with a binder, wherein a nonwoven cake is mixed in a drum and mixed in from this mixture Fiber fleece is formed, which is consolidated into a fiber mat in a needle machine. It also relates to the use of the fiber mats produced by the method and devices for carrying out this method.

State of the art

The method of the type mentioned is known from AT-PS 387.798. According to an advantageous embodiment of this known method, nonwovens are mixed in a drum and from this mixture further nonwovens are formed, for example on a nonwoven drum. It has been shown that the transport of the fiberized fiber mass from the drum roll to the nonwoven laying drum is untargeted, which leads to irregularities of the fiber cake on the nonwoven laying drum, such as an irregular basis weight distribution across the width of the nonwoven formed. It also shows that the wood fibers impregnated with synthetic resin come to rest largely due to their higher weight on the underside of the laid fleece, while the thermoplastic and / or the non-impregnated natural fibers of vegetable origin are arranged in the upper layer of the laid fleece . This different layer structure now leads to problems in the further processing of these fiber mats, since the underside of the fiber mats

REPLACEMENT LEAF becomes sticky due to its high binder content, while the top is hardly glued.

Presentation of the invention

The object on which the invention is based is that a deformable fiber mat of high tensile strength should have a regular weight distribution in its width and a layer structure which consists of regularly mixed fiber of impregnated and non-impregnated type.

On the basis of the method of the type mentioned at the outset, the invention provides to achieve the object that the fiber fleece cake 2.2 'is fed to a drum 6.6 *, in which the fiber fleece cake is defibrated, and that this is produced in this way Fiber mass 14, 14 'can be mixed by an air flow, the flow profile of which can be adjusted by the control elements 25, 26 mounted in an air duct 10, 10' as well as by a venturi rod 7, 7 ^{1 arranged} in the flow direction, whereby a fleece 18, 18 'is also mixed regular basis weight distribution is formed, which, after needling, is fed to a pressing device 21, 21 ', whereby a deformable fiber mat of high tensile strength 23, 23' is produced.

The method according to the invention is further characterized in that the control elements consist of a plurality of adjustment flaps 25 distributed over the width of the air duct 10 and of a plurality of control parts 26 which are convexly curved towards the air flow and whose curvature is adjustable.

The invention further relates to an advantageous use of the fiber mat produced according to the invention, which is characterized in that one or more of the fiber mats 23, 23 'is used for the production of molded parts by pressing under elevated pressure and elevated temperature.

REPLACEMENT LEAF The invention also relates to an advantageous device for the fluid dynamic production of deformable fiber mats of high tensile strength from a nonwoven fabric, consisting of cellulose fibers and thermoplastic fibers and / or natural fibers of vegetable origin impregnated with a binder, which are arranged one after the other in the direction of the material flow from a nonwoven laying machine 1, a pair of press rolls 3, 4, a pair of feed rollers 5, a drum 6, an air duct 10 which is fed by fans 12 and in which one or more control parts 25 in the form of one or more adjustment flap (s) are attached, a venturi rod 7 a diffuser. 13, a fleece laying drum 15, transport rollers 16, 17, a basis weight measuring device 19, a needle machine 20, a press device 21, a cutting machine 22 and a stacking device 24.

Furthermore, the invention relates to a further advantageous device for the fluid dynamic production of deformable fiber mats of high tensile strength from a nonwoven fabric, consisting of cellulose fibers impregnated with a binder and thermoplastic fibers and / or natural fibers of vegetable origin, which are arranged one after the other in the direction of the material flow from a fleece laying machine l ¹ , a pair of press rollers 3 ', 4', a pair of feed rollers 5 ', a reel 6', an air duct 10 ', which is fed by fans 12', in which one or more control elements 26 are convexly curved toward the air flow Shape and are adjustable in their curvature, a Venturi rod 7 ', from a diffuser 13', a fleece laying drum 15 ', the transport rollers 16', 17 ', a basis weight measuring device 19', a needle machine 20 ', a pressing device 21', a cutting ¬ demaschine 22 'and a stacking device 24'.

Some ways of carrying out the invention with the explanation of

characters

REPLACEMENT LEAF Fig. 1 shows the implementation of the method according to the invention by means of a device which is equipped with a control part in the form of an adjustment flap.

2 shows the implementation of the method according to the invention by means of a device with the corresponding reference numerals provided with lines, which is equipped with a control part which is curved in a convex manner towards the air flow.

3 and 4 show a perspective view in a schematic diagram of the venturi rods used as control parts in the method with the schematic course of the air flow.

In a fleece laying machine (1, 1 '), a mixture consisting of cellulose fibers impregnated with a binder, for example with a thermoset, thermoplastic or elastomer or mixtures thereof, and then dried, thermoplastic fibers, for example polyester, polyolefin, polyamide, polyacrylic -, EVA and / or natural fibers such as flax, hemp and cellulose fibers, a non-woven cake (2.2 *) is formed. This is then compressed by the feed rollers (3,3 ', 4,4') and fed by means of a pair of feed rollers (5,5 '), a drum (6, 6'), the surface of which is provided with needles or saw teeth which provide the De-fleece the fleece cake (2,2 '). By means of a number of fans 12, 12 'driven by the same axis, an air flow is generated in the air duct 10, 10', the flow speed of which can be adjusted by several control parts 25, 26 distributed over the width of the air duct (see FIGS. 1, 2). 1, the control parts are in the form of adjusting flaps 2, which are controlled by adjusting devices 11, 11 '. The control parts 26 (see FIG. 2) are curved toward the air flow, the curvature of which is adjustable.

The mixing of the fibers in the air flow also depends on the flow rate. This mixing is carried out by the

REPLACEMENT LEAF ^~ Provided an optimized Venturi rod 7,7 'which can be rotated around its axis by 30 ° and which has webs 8,8' which can be modified in width. In the slots 9, 9 * produced between the webs 8, 8 '(see FIGS. 3 and 4), the flow rate of the air-fiber mixture is increased, depending on the width and rotational position of the slots, as a result of which the fibers 14, 14' in are additionally mixed the downstream diffuser 13, 13 '. Furthermore, such a variable flow rate causes a scoop effect, which enables the fibers 14, 14 'to be laid regularly on the fleece laying drum 15, 15'. The newly formed fleece 18, 18 'is over the transport rollers 16, 16'. and 17, 17 'of the basis weight measuring device 19, 19'. These measurement results indicate ■ a more regular basis weight distribution than those measurement results which could be achieved with the known methods for forming fleece. If the basis weight distribution is nevertheless insufficient, it can be varied by changing the flow velocities by adjusting one or more control parts 25, 26. Furthermore, the adjustability of the venturi rod 7, 7 'provides a further possibility for optimizing the flow conditions.

In the subsequent needling machine 20, 20 ', the fleece 18, 18' is needled with a further fleece 27, 27 ', for example consisting of polyester, polyamide, glass fibers or jute, whereby a sufficiently deformable fiber mat 28, 28' is formed. However, in order to ensure better deformability of this fiber mat during further processing in molding presses, it is passed through the pressing device 21, 21 ', which can be, for example, a calender or a belt press. The fiber mat is pre-compressed between the calender rolls at a temperature of 25-150 ° C. and a specific pressure of 5-50 kp / cm ² , the wood fibers impregnated with synthetic resin being bonded even more firmly to the foreign fibers. As a result, the fiber mat can also be higher during further processing, for example during compression molding

REPLACEMENT LEAF Absorb tensile forces and is therefore less susceptible to crack formation.

The pre-compressed mats 24, 24 'are then stacked on passing through the cutting machine 22, 22' on the stacking device 23, 23 '.

Industrial applicability

The fiber mat produced by the method according to the invention is advantageously used for the production of molded parts by pressing under increased pressure and elevated temperature.

REPLACEMENT LEAF

Claims

Claims; 1. Process for the fluid dynamic production of deformable fiber mats of high tensile strength from a non-woven fabric, consisting of cellulose fibers and thermoplastic fibers and / or natural fibers of vegetable origin impregnated with a binder, a non-woven cake being mixed in a drum and a non-woven fabric being formed from this mixture, which is solidified in a needle machine to form a fiber mat, characterized in that the fleece cake 2,2 'is fed to a drum 6,6' in which the fiber fleece cake is defibrated, and in that this fiber mass 14, 14 'is formed by a Air flow, the flow profile of which can be adjusted by the control elements 25, 26 attached in an air duct 10, 10 'and by a venturi rod 7, 7' connected downstream in the direction of flow, whereby a fleece 18, 18 'with a regular basis weight distribution is formed, which according to Needling a press device ung 21, 21 'is supplied, whereby a deformable fiber mat high' tear strength 23, 23 'is generated. 2. The method according to claim 1, characterized in that the control elements consist of a plurality of adjustment flaps 25 distributed over the width of the air duct 10. 3. The method according to claim 1, characterized in that the control elements consist of several control parts 26 which are convexly curved towards the air flow and adjustable in their curvature. 4. Use of a deformable, high tear strength deformable fiber mat, characterized in that one or more of the fiber mats 23, 23 'for the production of Shaped parts by pressing under increased pressure and elevated temperature is used. REPLACEMENT LEAF 5. Device for the fluid dynamic production of deformable fiber mats of high tensile strength from a non-woven fabric, consisting of cellulose fibers and thermoplastic fibers and / or natural fibers of vegetable origin impregnated with a binder, characterized in that the device is arranged in material flow in succession from a fleece laying machine 1, one Press roller pair 3, 4, a feed roller pair 5, a drum 6, an air duct 10, which is fed by fans 12 and in which one or more control parts 25 in the form of one or more adjustment flap (s) are attached, a venturi rod 7, from a diffuser 13, a fleece laying drum 15, transport rollers 16, 17, a basis weight measuring device 19, a needle machine 20, a pressing device 21, a cutting machine 22, a stacking device 24. 6. Device for the fluid dynamic production of deformable fiber mats of high tear strength from a nonwoven fabric, consisting of cellulose fibers and thermoplastic fibers and / or natural fibers' of vegetable origin impregnated with a binder, characterized in that the device is arranged one after the other in the material flow direction from a nonwoven laying machine 1 ', a pair of press rollers 3', 4 ', a pair of feed rollers 5', a reel 6 ', an air duct 10', which is fed by fans 12 ', in which one or more control elements 26 in a shape convex towards the air flow and in are adjustable in their curvature, a Venturi rod 7 ', made of a diffuser 13', a fleece laying drum 15 ', the transport rollers 16', 17 ', a basis weight measuring device 19', a needle machine 20 ', a pressing device 21', a cutting machine 22 ', a stacking device 24 '.