DE2104559A1 - - Google Patents

Description

DR. BERG DIPL.-IWG. STAPF

PATENT LAWYERS 8 MUNICH 8O. MAUERKIRCHERSTR. 45

• Dr. Berg Dipl.-Ing. Stopf, 8 MOndien 80, Moüerkircherstra6a 45

Your sign Your writing Our sign

date

J. Feb. 1971

Lawyer file 2o 568

Monsanto Company St. Louis (USA)

"Stretchable tangled nonwovens"

This invention relates to elastic random webs - often also called iJon-Wovens - and in particular random webs made of continuous, non-elastic, organic, synthetic threads in which essentially all threads oriented in a given direction are curved

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v.other threads that are at a '-angle to the given direction oriented and curved to the same or lesser extent to form tangled nonwovens with elastic elongation and spring back in the given: direction.

Random nonwovens and in particular those made of spun fibers made from continuous synthetic threads win the textile sector due to their high strength per volume compared to woven or knitted fiber fabrics or tangled nonwovens made of staple fibers are becoming increasingly important. So far, nonwovens have suffered from continuous Threads at the disadvantage of not being flexible and not having elastic stretch properties, which would make them fit when used. Random nonwovens made from staple fibers have previously become stretchable as a result made by incorporating elastic threads into the fabric during its manufacture, as in the US patent 3,468,748. V / non-woven from continuous filaments have been made more flexible by crimping the filaments and the Tying threads together by arranging the binding threads in separate strips over the entire thickness of the fabric, as described in U.S. Patent 3,459,627 is. Is of interest in this context

10983B / U52

also US Pat. No. 3,326,720, since it describes a random web which has the ability to stretch in different directions and to take up its initial shape again, the fiber sheet being a combination of a thermoplastic binder with staple fibers, the 8 has up to 16 crimps / cm (2o to Ho per inch).

While the above-mentioned patents show ways, some occur with tangled webs made of continuous threads To overcome problems, the tangled nonwovens produced by known processes do not produce any structures which show desired elastic elongation and flexibility for in-use fit, since those used heretofore Tying process limit thread movement. The threads must be movable between the binding sites and all Threads within the entire thickness of the fabric must be deformable and at the same time after deformation their former Take shape again. For example, if a thread is crimped between the binding points, i.e. the thread length between the binding sites is greater than the straight line distance and the thread is either above or below or straightened to either side between the same distance from binding sites, so may Tissues cannot be stretched without breaking either the binding sites or the threads because of the straight

-M-

10983B / U62

210455S

Thread prevents such stretching. So that an expansion of the fleece is possible, practically all of them have to be approximate threads lying in the intended direction of elongation between the anchoring parts have a length, which is much larger than the straight line distance between the binding sites. Such a thread arrangement can not be achieved according to the known method, even with heavily crimped threads, if a practically complete bond then occurs after the threads are in a relaxed, i.e. in a state exist in which no thread movement occurs in a tension-free environment.

The invention described below includes a in various ways elastically stretchable random fleece made of continuous, organic, synthetic threads as well the method and apparatus for producing the nonwoven fabric. The continuous threads are within the whole fleece arranged so that they are substantially separate and independent of each other, except at the crossover points where the threads are often connected to one another. This bond can be different Were effected, for example by a thermoplastic resin, by binding fibers or on autogenous Manner, whereby both partial and full binding can be achieved. Under

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"Autogenous binding" is to be understood as the connection of threads without external binding agents, for example one Connection by gas as described below and a connection of conjugated or sheath-core threads through warmth. A large number of the continuous filaments are curved, looped or curled, many of the curved filaments being arranged approximately in a given direction without any filaments in are straight in the same direction. According to the invention, straight threads in the fleece are in directions arranged at an angle to the direction in which the curved filaments are arranged. It can but also a number of curved threads can be arranged in other directions that correspond to the orientation of the straight threads can collapse; a resilient, elastic structure is not to be expected, however, v / o the Curved and straight threads lie in a common direction, as the stretching of the fabric leads to breakage either the threads or the connection points leads in this direction.

The method for producing nonwovens according to the invention comprises:

(a) dayman is a flat structure made of continuous,

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produces synthetic threads, the threads being arranged so that they are substantially separated and from one another, except at the points of intersection of the threads are independent;

(b) that one sees the touching ones at the crossing points Partially connects threads with one another, whereby the partial bindings enable the threads in proportion

to rotate relative to one another around the bindings, the joints serving as pivots;

(c) tensioning the network along a first direction around a number of threads in that pitch out - and straighten and align and bend a number of threads in a second direction that is at an angle to the first direction, and

(d) that while maintaining tension on the network, the bond is made completely around the threads to connect the connection points firmly to one another.

A plant for the production of a stretchable nonwoven fabric from a network of continuous, organic, synthetic threads, wherein the threads are separated and from each other are independent, except that they are attached to thread

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touch intersection points, has a device for bringing about a partial bond between the at numerous crossover points, the bonds en Allowing the threads to rotate, a device for tensioning the network around numerous threads in the direction of the applied Aligning and straightening tension and aligning and closing numerous threads in one direction bend that is at an angle to the direction of the applied tension, and continue to put a device on it to make full of the partial ties so that the threads become firmly bonded together while stretching the network is in a strained state.

The subjects of this invention are:

- an improved random fleece with new physical and aesthetic properties, such as a softer handle, decreased stiffness and surface friction;

- a tangled fleece made of continuous, organic, synthetic Threads with a high elastic elongation which gives the material conformability in use;

- A process for the production of a random fleece from continuous, organic, synthetic threads with strong elastic stretching or stretching that resumes its previous shape, reduced stiffness and improved Handle;

- A device for the production of a random fleece from continuous, organic, synthetic threads with

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high elastic elongation.

The invention is explained in more detail below with reference to the drawings explains where

Pig. 1 is a schematic diagram of the device for

Manufacture of the stretchable random web according to this invention and for carrying out the invention fc represents procedure;

Fig. 2 is a schematic representation of a random fleece,

the

the / shows the flameless arrangement of the threads within the network;

Fig. 3 is a schematic representation of a tangled web showing that many of the substantially straight Threads aligned in a first direction and many of the curved threads aligned in a second direction arej. which is at an angle to the first direction;

* Fig. 4 is a photograph enlarged 47 times

is non-stretchable random fleece;

5 is a photograph enlarged 51 times of the in

Fig. 4 is shown fleece after the fleece according to the invention has been processed;

6 is a photograph enlarged 45 times of the im Available under the trademark

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"Reemay" fabric is a fabric made from woven polyester fibers .

Fig. 7 is a photograph enlarged 4o of the im Commercially available "Reemay" is that of the process has been subjected to this invention;

8 a photograph in 19-fa rather an enlargement of the in Figure 4 is the network shown;

9 is a photograph enlarged 2o times of the in Figure 5 is the network shown;

Fig.Io a geometric representation of 5 partially connected Is threads that are randomly present in the web;

Fig.11 is a geometric representation of the threads as they are shown in Fig. Io after the fleece from which these threads are a part that has been drawn, the illustration being the twisting of these threads around the joint Shows connection points and the formation of curved threads, and

Figure 12 shows the stress strain curves in the machine and transverse direction of a control web and a nonwoven fabric, which according to the present invention has been edited.

A resilient, stretchable web in accordance with this invention can be made with the apparatus shown in FIG. A melt extrusion press Io is used for spinning continuous nylon threads 11. The threads 11 are downward

guided and detected by the suction device 12, the vertical 10983B / U52

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is arranged at a distance under the extruder. The suction device 12 conveys the threads 11 downwards to a deposition zone by means of compressed air which is passed through a (not shown) Line is fed. The deposition zone consists of an endless, perforated conveyor belt 14, - called in English foraminous belt - this is set by rollers 15 and 16, one of which is driven via a fixed Is led away. Though the one by the conveyor belt

™ can be changed, it is provided that it is flat at least in the area that receives the threads 11 from the suction device 12. The deposition zone also includes a vacuum device 18 which is in the form of an open box containing the suction device 19. The vacuum source 18 is located immediately below the suction device 12 and below the conveyor belt 14, so that the threads 11 are held on the conveyor belt Ik while the threads are deposited on this. The length of the vacuum source 18 in the direction of the roller

ψ should be sufficient to hold the threads tightly on the tape Ik . Depending on the working conditions, a second vacuum device or a weaker suction device (not shown) may be expedient, which is arranged essentially at the vacuum device 18 in the direction of the roller 16.

The network 17 is removed from the conveyor belt 14 by the pressure rollers 3o and 31 at the moment when the belt begins its arcuate path around the roller 16. We-

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At least one of the pressure rollers is driven. Unless that Network 17 consists of nylon threads, the stage of partially tying the threads can take place in the gas chamber 29, those with hydrogen chloride gas or a similar activating gas, according to US patent application Ser. 737 5o9 of June 17, 1968, is filled. The activation gas can also be dissolved in an organic liquid carrier which is inert to the filaments, as in the US patent application Serial No. 72o 614 of April 11, 1968. The nylon threads partially absorb the hydrogen chloride at least on their surfaces. The hydrogen chloride molecule absorbed in the nylon causes the breakage the hydrogen bond that exists between the adjacent amide groups and after removal or desorption of the hydrogen chloride from the nylon, the hydrogen bonds are re-formed, some of these bonds being formed lead to the formation of bonds between the amide groups of different threads (at crossover points).

In this embodiment absorb when the network the gas chamber 29 passes through the nylon threads, at least on their surfaces, the hydrogen gas. The absorption of the gas makes the threads suitable for bonding. To the extent that the pressure rollers 3o and 31 the fleece 17 pull out of the gas chamber 29, the hydrogen chloride begins to evaporate from the nylon threads and there is a partial

109835 / H 5 2 " ¹² "

Binding between the touching threads. When the fleece passes between the rollers 3o and 31, the threads are brought into closer contact in order to increase the number of possible binding sites. The fleece 17 is then guided over the translation rollers (guide rollers) 36 and 37, which have a higher peripheral speed than the peripheral speed of the pressure rollers 3o and 31. The web is therefore stretched between the pressure rollers 3o and 31 and the transmission roller 36 in accordance with the respective ratio of the peripheral speeds. However, a gas desorption _{device 3 ^ 5,} which can be a heating device or a water bath, is attached between the pressure rollers 3o and 31 and the transfer roller 36, and after the fleece has entered the gas desorber 3 ^, the hydrogen chloride gas is practically completely removed from it The fleece is removed, making the bonds complete. Once the bonds between the touching threads have been completed, the web is no longer in a state in which it can be stretched. Essentially all of the stretching takes place within the fleece between the pressure rollers 3o and 31 and the gas desorption device 3 ^. The fleece 17 is in a partially connected state when it passes through the pressure rollers 3o and 31. The partial binding can be facilitated by heating either one or the other pressure roller 3o or 31. In a partially connected state

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the threads are able to react to the tension in the fleece by rotating around the binding points. The embodiment described above can be modified in such a way that the pressure rollers 30 and 31 are attached between the conveyor belt I ¹ J and the gas chamber 29 in order to carry out the web stretching as long as the web 17 remains in the gas chamber 29.

Fig. Io shows that the threads 50 to 54 are arranged randomly and are partially connected at the binding points "a", "b", "c" and "d". The threads 5o to 54 respond to the train, as shown in FIG. 11, in such a way that they rotate about the corresponding binding points. For example, the threads 5o, 52 and 54 rotate or move around the binding point "a" as a pivot point in the position shown. After completion of the binding at "a", the threads 50, 52 and 54 remain in this rotated position, the binding having fixed these threads in this position. A subsequent deformation, for example in the transverse direction, is opposed by the curved thread 54 no resistance, and have been made if the linkages in Fig. Io to complete permanent after removal of the deformation force returns the thread system substantially to that shown in Fig. Position shown 11 back " a transverse force would have been resisted by the suture 54 with negligible elongation. The irregular course taken by the thread 54 as shown in FIG

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11 is referred to herein as "curved" which is to say the length of the thread between two Points is greater than the straight line distance. The curvatures can be in the form of loops, waves, and twists The like. which are due to the bending of substantially at right angles to the applied tension Thread segments are caused. This curvature is the result of the Poisson effect, i.e. the shrinkage of the Fleece width is caused by the stretching of the fleece. This mechanism is facilitated by a softened State of the binding and the thread between the binding points, which enables a certain amount of thread rotation around the binding axis. After rapid completion of the bonds while maintaining the internal tension resulting from the external tension becomes the modified one Maintain the fabric geometry, which becomes the stable form of the fleece. Such a fleece shows considerable elongation and springback properties at right angles to the direction of the applied stress. In Fig. 11 show the arrows indicate the direction of the applied tension.

The stretching and resilience properties of the fleece can be expressed as a percentage of the reversible stretching. Reversible elongation is the percentage by which the nonwoven fabric changes as a result of the curling or uncrimping of the Threads can lengthen before an actual tension arises

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the threads or thread bindings are exercised. Curves for a standard random web, the production of which is described in Example 1, which was stretched in the machine direction, S (M) and the transverse direction S (T), and for a random web, which was produced according to Example 2 and in the machine direction P ( M) and the transverse direction P (T) are shown in FIG. A tangent is applied to the corresponding stress-strain curves at the maximum slope, and the percentage of reversible strain is determined as the linear expansion between the point of intersection of the tangent with the strain axis and the starting point of the stress strain. Curves S (T), S (M) and P (M) show negligible reversible elongation, while curve P (T) shows reversible elongation of approximately 27%.

The method according to the invention is also applicable to other binding methods applicable. For example, a random fleece can be produced from connected continuous threads by that a network of synthetic high and low melting point threads such as nylon 66 and nylon 6 is made. The threads, which are extruded from different spinnerets, are fed to a common suction device and stocked on a foraminous conveyor belt as described below. The tissue will then

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to a temperature above the melting point of the polycaprolactam threads, but below the melting point the polyhexamethylene adipamide threads are heated, whereupon the Polycaprolactam threads lose their identity as such, wander to the spaces between the polyhexamethylene adipamide threads touching them and so a possible Create a binding point. While the pdycaprolactam in is in a molten state and forms a partial bond at the bond point, the nonwoven is stretched, so that certain threads are oriented in the machine direction and other threads are oriented in the cross direction are to be curved as a result of the Poisson effect. The mat is allowed to cool while it is held under tension becomes, and the modified fiber structure becomes the real stable framework after completion of the bond.

The stretchable webs of this invention can also be made from continuous filaments, such as polyester filaments, bonded with a thermoplastic latex binder. Continuous polyester filaments are applied to a foraminous belt in the manner described above to form a disconnected network. This is then impregnated with a latex binder such as a latex made of vinyl chloride-vinyl acetate copolymer. The partial bonding w ± rd achieved by increasing the temperature of the mat to remove the water on Io'J ⁰ C (22o ° F) and then the temperature 10983B / UB2 _ _1? _

210A559

to melt the latex to about 150 ° C (300 ° P). At 15o C (3oo P) the fleece is stretched, whereby the When softened, latex allows the thread to rotate. The bonds are thereby permanently strengthened, daft the temperature of the fleece is reduced to substantially room temperature, while the fleece is kept under tension. The fleece has stretch properties at right angles to the direction of the applied tension.

The nonwovens according to the invention can also consist of continuous sheath, core and side-by-side in pairs Threads are made. Such threads consist of at least two different polymers, which what the cross-section of the thread arrives in a certain pattern. If the threads are of the sheath-core type, then the The core is a polymer with a high melting temperature, and the polymer of the shell has a low melting temperature. The fleece is made in the manner described above, whereupon its temperature is above the melting temperature of the low-melting polymer, but below the melting temperature of the polymer with a high melting point is increased. The polymer with a low melting point migrates to the intersections of the threads and forms the partial ones Ties. The fleece is then stretched,

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to enable the load to take care of the partial binds to rotate and to align and bend in the direction transverse to the stretching direction according to the Poisson effect » After the twisting of the thread has been effected, the fleece is below the melting temperature of the polymer preparation with a low melting point chilled to fix the sutures in their newfound position.,

example 1

The device of Fig. 1 was used to consist of a

continuous thread a nonwoven fabric of 34 »5 g / m (1 oz./ sq..yd «) The fleece in this example actually has no elongation properties and serves as a control for the later examples.

Nylon 66 flake having a relative viscosity of 38 were two screws melt spinning apparatus with a * diameter of 2.5 cm χ 53 cm Screw length (1 in. Χ in "21) supplied to said device at a temperature of 320 ⁰ G worked and was driven at a speed of 40 rpm. Molten nylon was fed to each screw from two melt pumping blocks fitted with geared metering pumps. Each melt pump block was provided with a spinneret pack containing a spinneret with 10 orifices, the orifices being 0.228 mm (9 mils) in diameter and

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Capillary lengths, of 0.308 mm (12 mils). The melt pump blocks were kept at a temperature of, while the spinneret had a temperature of 262 ⁰ O ,, the Extrudierungsgeschwindigkeit of the molten polymer from the spinneret AuBtrittsöffnungen Detrug 0.75 g / min per orifice.

The multitude of continuous threads were evenly divided and 5 suction devices were fed to and through them, with air supplied at 4 »2 ata (60 psig) pressure. The suction devices were in one aligned row that is transverse to the direction of movement of the deposit conveyor belt 14 runs. The thinned threads were directed by the suction devices is moved onto the deposition belt by means of the air emerging from the suction devices, whereupon the threads as continuous Fleece was deposited in a width of 45 cm. »The deposition conveyor belt had a surface speed of 0.76 m / tlin. (2.5 fto / min ») ,,

The nonwoven fabric became continuous forward to and through the gas application chamber 29 by means of the deposition conveyor belt 14 and rollers 30 and 31 moved through, the HCl gas as a binding aid at a rate of 6.5 g / min. That HGl gas is used to soften the surface of the threads. The threads are then grounded together as long as they are in the soft

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are made state, compacted by means of the rollers 30 and 31. The partially bonded nonwoven structure was then a temperature of about 115 O through the heater 34 subjected, whereupon the HGl gas is desorbed and simultaneously so that the bond between the adjacent touching threads was effected.

The web was fed through the heater 34 and the take-up roll (not shown) via rolls 36 and 37, which are in the essentially at the same speed as the rollers 30 and 31 were driven.

The physical test of the fiber fleece produced in this way showed the following properties:

strength

Density (g / cm ³ )

Tear length

(lb / in / oz / yd ² ) reversible (elastic) elongation ^

Bending length

* M.Do = machine direction of the fleece

* ToDo = transverse direction (transverse direction

of the fleece)

The percentage of reversible (elastic) stretch is the percentage of stretch that the fabric allows without

109835 / U52 ~ ²¹

ο, 25: mm (1 0 mils) ο, 13th MoDo * 9, 3 Death.* 6, 5 MoDo ο, 20th Death. ο, 65 M. D. 66 mm (2 , 6 in.) Death. 50 mm (2 , 0 in.)

that a "significant tension either on the threads that the fleece contains or is applied to the thread bindings »With reference to Pig. 12 becomes the percentage of reversible (Elastic) elongation obtained by the fact that the tangent to the maximum curve shape of the fleece stress-strain curve back to the elongation axis, as shown in curves S (T) and S (M) in Pig. 12 is displayed, extrapolated » The strain magnitude from this starting point is defined as the percentage of reversible (elastic) strain.

Example 2

The apparatus and procedure as used in Example 1 were used repeatedly except that the following process conditions were changed to form an elastically stretchable nonwoven made of continuous filaments weighing 25.2 g / m (0.75 ozo / sq.yd,).

After softening the surface of the threads with HGl gas became the fiber structure through rollers 30 and 31 and then to and through the HOl gas desorption heater 34 the reels. 36 and 37, which have a surface velocity 1.5 times greater than the surface area speed of the rollers 30 and 31 were driven. As a result of the speed of the rollers 36 and 37, the Fleece structure 1.5 times stretching in the machine setting (M.D.) and contraction to a width of approximately 30 cm (12 in.) In the transverse direction (T.D.)

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ORlQVNAL

worfen "before the desorption of HCl gas was conducted by the heater 34, wherein it was maintained at a temperature of 120 ⁰ C. The desorption of the HCl gas caused the complete formation of the" inter-filament "bonds, d _e h that is, the bonds between the threads while the web structure was in tension, and the web thus bonded was packaged on a take-up roll with a width of 30 cm (12 in.).

The photomicrographs of the modified web shown in Figures 5 and 9 show a large number of curved ones Fiber segments to substantially in the transverse direction the axis of elongation, with the curved threads predominantly in the direction of the reversible (elastic) Stretching lying.

The physical examinations of this nonwoven fabric showed the following properties:

Thickness 0.35 mm (H mils)

Density (g / om ³ ) 0.073

Tear length M.D. 5.8

(lb / in / oz / yd ² ) ID 2.2

generally reversible (elastic) elongation MD 0.4

T.Do 22.4

Bending length Ld.D. 6.8 cm (2.7 in.)

Death. 1.5 cm (0.6 in.)

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It can be seen that "a significant increase in the percentage of reversible elongation in the transverse direction compared to the reversible elongation of Example 1 was obtained. Curve P (T) as shown in Fig. 12 graphically illustrates the aforementioned increase "Likewise, the tie length in the transverse direction was low _o

Example 3

An elastically extensible non-woven fabric (non-wovens) was made as in Example 2, except for the processing apparatus and the process conditions were changed to form a fabric weighing 17 g / m (0.5 oz./sqoydo) of threads that form a flattened, ribbon-like Had cross-section. The threads had an aspect ratio of 3s1, the aspect ratio being the maximum Thread width divided by the minimum thread thickness.

Mylon flakes with a relative viscosity of 38 were made introduced into screw extruders driven at a speed of 39 rpm. The pump blocks were equipped with spinnerets that have 14 rectangular orifices 0.07 x 1.01 mm (3 mils x 40 mils), the capillary length was 0.5 mm (20 mils). The rate of extrusion of the molten polymer through the outlet openings was 11.3 g per hour "

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The 7 suction devices were supplied with air at 4 »4 ata (64 psig) pressure and the diluted filaments emerging from the suction devices were deposited as a fibrous structure 45 cm (18 in.) Wide on a perforated deposition conveyor belt, this having a surface velocity of 1.4 m / ttlin _o (4 »6 ft _o / min _o )"

The web was passed between the rollers 30 and 31 after allowing in the gas chamber 29 HOl act on it, said supplied HCl gas was absorbed by the web by means of the heater 34, operating at a temperature of 110 ⁰ C.

The stretched and bonded web had a web width of about 2b cm (11 in ") at the receiver ο lie. The The following figures were obtained from the physical test of the nonwoven produced in this way.

Thickness 0.335 mm (13.8 mils)

Density (g / cm ⁵ ) 0.048

Tear length MoD. 2.7

(lb / in / oz / yd ² ) T ₀ D ₀ 1.6

<fo reversible elongation M ₀ D. 0.22

I.D. 29.0

Bending length M.D «4.57 cm (1.8 in)

Death. 1.5 cm (0.6 in)

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Comparison with the results of Example 2 shows that the fleece from flatter loads results in higher elongation values in the transverse direction »

Example 4

A stretchable web was made as described in Example 3, except that the machine direction stretch was only 1.1 times, resulting in a web take-up width of 45 cm (17 in.). The batt weight was 17 g / m (0.5 oz / sq. ₀ ydo).

Physical testing of this fleece showed the following Results.

Strength ., M.D 0.50 mm ( 12th mils) Density (g / cnr) T.Do 0.058 Tear length M.D. 6.0 (lb / in / 0z / yd ² ) T.D. 5.7 i » reversible elongation M.D. 0.20 16.4 Bending length 4.5 om (1 ,8th inc)

T.D. 2.2 cm (0.9 in)

Although the web of this example was stretched only 1.1 times its initial length, a significant increase in the percentage of elastic recovery in the transverse direction was observed compared to the control of Example 1 which had essentially no stretch.

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Example 5

A stretchable non-woven fabric that has an equal number of nylon 66 (polyhexamethylene adipamide) threads and nylon 6- (polycaprolactam) -3 pods was used in that described in Example 1 Manner with the following exceptions regarding the process parameters and conditions.

_{The nylon 6-0} flakes, which had an R 0 V ₀ of 38, were fed to one screw extruder and the nylon 6-J ¹ curls to a second screw extruder. The son corner working temperature for nylon 66 was kept ⁰ G at 32O, v / hile it was maintained at Nylon 6 at 290 ⁰ C "Both screws were driven at a speed of 32 rev / min""Each screw conducted two melt pumps blocks to the molten nylon, which were equipped with G-etriebemeßpumpen, where they were driven at 20 rev / min _o. Each melt pump block was provided with a spinneret pack containing a spinneret assembly with multiple orifices (H), each orifice having a diameter of 0.3mm (12 mils) and 0.228mm (9 mils) in diameter with a capillary length of 0.3mm (12 mils). The nylon 66 pumps blocks were kept at a lemperatur, of 315 C and its associated spinneret at 264 ⁰ G, while the nylon worked 6-pump blocks at a temperature of 285 C and its associated spinneret packs at 235 ⁰ O. The rate of extrusion through the large number of nozzles was 10.6 g / min.
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The continuous filaments from the spinnerets were in Split 8 equal bundles, each bundle containing an equal number of nylon 66 and nylon 6 strands. the The bundled filaments were then fed to eight suction devices operating at 4.4 ata (62 psig) air pressure became. The high air speed of the suction device weakened, mixed or confused and moved them load forward to the holed deposit conveyor belt as a continuous web with a width of 45 cm (18 in.).

The structure formed from threads thus deposited was conveyed continuously by means of the conveyor belt 14 and through the rollers 30 and 31 to and through a heating furnace in which the temperature was kept at 200 ^° C., whereby the nylon 6 threads were sufficiently softened to the bond between the threads between the nylon 66 and nylon "to allow 6 yarns at their i contact points, the forward-mentioned heat source was used in place of the gas chamber 29, and was located at the same corresponding position, so that the fiber structure by the Vfelzen 30 and 31 was squeezed while the nylon 6 strands were sticky or softened.

After the nonwoven has been alzen the li / exit 30 and 31 and then brought again to a temperature of 200 ⁰ G by means of a heater 34, it was stretched by 1.5 times in the machine-

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direction through the work of the forward stretching Rolls 36 and 37 drawn, the surface speed of which was 1.5 times that of rolls 30 and 31. The plasticized UyIοη 6 component of the fleece made it possible a new orientation of the bonds existing between the threads »The fleece was after its exit from the heater 34 is rapidly cooled at a modified width of approximately 30.5 cm (12 in.) using a fan used to strengthen the nylon 6 component, before the web with the advancing roller 36 came into contact and was then taken up as a continuous, reversibly stretchable fleece.

The test of the elastic-stretchable fleece showed the following physical properties: ₀

weight M.D. 24.7 g / m ^fc (O , 75 02 strength T.D. 0.38 mm (15 mils) Density (g / cnr) MoDo 0.067 Tear length Death. 5.2 (Ib./in/oz/yd ² ) M.D. 2.5 <fo reversible elongation To do 0.5 26.2 Bending length 6.6 cm (2.6 in.) 1.27 cm (O, 5 in.)

While the reversible elastic elongation in the transverse direction remained high, a decrease in the length of the ReÜ31 was found, because the nylon 6 component that is essentially

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was melted, primarily as a binder and did not serve as a load-bearing part

Example 6

Fleece samples measuring 22.8 χ 12.7 cm (9 χ 5 in.) from the commercially available fleece Reemay *), company designation 20 17 and 2222, those made from trilobal non-crimped or «, crimped fibers were produced, as indicated below, with the formation of nonwovens which exhibited reversible stretching in one direction.

Two of the above specimens of each type were clamped in separate frames? everyone The frame had a fixed clamp position and a clamp operated with a screw. The clamps held them Fleece at their edges in the shortest length.

The entire frame and nonwoven samples were then placed in an oven in which they were heated to a temperature of 210 ⁰ O, wherein the webs were relaxed. The elevated temperature resulted in the softening of the fusible binding component of the webs, and in this condition the web samples were stretched 1.8 times their initial length by operating the screw-connected movable clamps of each frame.

*) Trademark of E.I. du Pont de Nemours and Company of Wilmington, Delaware for their polyester nonwovens

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After the webs had been stretched to a temperature of 21O ⁰ G, the frames with the webs were removed from the oven, whereupon they were quickly cooled to room temperature in order to re-solidify and reorient the interfilamentary bonds to form stable webs that had a width approximately 7.1 cm (2.8 in.).

The photographs as shown in Fig. 1 show that the modified nonwovens have a large number of curved fiber segments in a direction that lies substantially transverse to the axis in which the webs were stretched, which is the predominant elastic direction of stretching is equivalent to. In Fig. 6, which shows the fleece of Pig. 7 shows before processing, the shutters were arranged in an unordered manner and no curvature of the thread can be seen.

The nonwovens had the following properties.

M.
T .D.
.D. Reemay fleece
2017 Reemay fleece
2222 strength 0.43 mm
(17.2 mils) 0.48 mm
(19.7 mils) Density (g / enr) 0.131 0.154 Tear length
(Ib./in/oz/yd ² ) 4.66 3.87 * fo reversible

strain

M. D.

17.7

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23.0

The nonwovens had "before the process according to the invention were subjected to the following properties

Mon do Reemay fleece Reemay fleece Tc do 2017 2222 strength 0.25 mm 0.43 mm M. Dc (10 mils) (17 mils) Thickness (g / cm) To Dc 0.208 0.178 Tear length 11.41 - (lb / in / oz / yd ² ) 6.07 7.39 io reversible strain 0.38 - 0.19 0.25

Example 7

A 12 22.8 cm (5 "χ 9") "heterofil" (a commercially available Fleece from Imperial Chemicals Industries, the fleece being made from continuous sheath-core Kylon threads with a nylon 66 (polyhexamethylene adipamide) core and a nylon 6 (polycaprolactam) sheath "and the threads together are connected by melting the shell components), was clamped relaxed in a stretching frame. The entire arrangement (frame plus fleece) was heated in an air circulation oven at 175 ° for 3 minutes. While staying In the heated oven, the nonwoven sample was stretched Ity2 times its length. The arrangement was taken from the Oven removed while it was still under stretching conditions and allowed to cool to room temperature »

Testing of the nonwoven fabric treated according to the invention and

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of the untreated fleece gave the following physical properties:

To do Untreated
Control ' Treated Weight ρ
approx »34.5 g / m
- (1.03 oz / yd2) ρ
approx. 34.5 g / m
(1.03 oz / yd2) strength 0.38 mm
(15 mils) 0.30 mm
(12 mils) Density (g / cnr) 0.09 0.11 Tear length 9.3 4.0

(lb / in / oz / yd ² )

$ reversible DehngoToD. 2. 32

One can see that a stretch is only iY2 times Provides a nonwoven that has a significantly improved reversible elastic elongation in the transverse direction »

-33- 109835 / U52

Claims (1)

- 33 claims: 1 · Elastic-stretchable fleece made of continuous, organic, synthetic threads, characterized in that the threads are separated from each other and arranged independently with the exception of the! Directionally oriented, substantially aligned or strongly curved with other threads which are oriented at an angle to this given direction and are curved to the same or lesser extent, the threads being distributed in each direction through the entire fleece, _etc. 2, fleece according to claim 1, characterized in that the threads are nylon, polyester, a mixture of two fiber-forming polymer threads with different melting points, the mixture of the two fiber-forming polymer threads being separate threads of a single fiber-forming polymer or a thread consisting of at least two Components with different melting points exist. .I ■ ■. ■. 3 · nonwoven claim 2 characterized in accordance that the yarns at the crossing points touch and autogenously with each other at the crossing points connect. -34- 109835/1 U 5 2 4. Fleece according to claim 2, characterized in that the threads at the crossing points by means of a thermoplastic Latex are connected, with the threads being adjacent or joining with others at the crossover points touch. 5 »fleece according to claim 2, characterized in that the The bending length in the transverse direction to the first direction is less than half the bending length in the first direction. 6. fleece according to claim 2, characterized in that the Threads have a non-circular cross-section. 7ο fleece according to claim 6, characterized in that the threads are ribbon-like, they have an aspect ratio of
be at least 2: 1. 8ο fleece according to claim 6, characterized in that the synthetic threads are trilobal in their shape. 9 »Process for producing an elastic-stretchable
Fleece characterized in that one a, continuous filaments of at least one fiber-forming synthetic polymer melt extruded j b. collects the threads in the form of a fleece, the threads being essentially separate and apart from one another 109835 / U52 the cross-hairs, are independent, the cross-points forming potential binding parts; ο »the touching threads with the multitude of binding points partially oindet to allow the thread twist on the binary parts; d _o tensioning the web in a first direction to orient and straighten a plurality of threads in that first direction and to orient and straighten a plurality of threads in a second direction at an angle to the first direction bend, and e. to convert the flexible bonds into firm bonds in order to make the touching threads with one another at the binding points to be fastened while the fleece is kept under tension 10ο The method according to claim 9, characterized in that a polyamide is used as the polymer melt Partial bonding is effected by exposing the polyamide threads to a chemical activating gas and making them flexible Converting bonds into firm bonds by desorbing the gas from the threads ο The method according to claim 9, characterized in that the partial binding of the touching threads is 109835 / U52 " ⁵⁶ ~ has the effect that you can see the binding points with a thermoplastic The latex, which is stretched in front of the nonwoven fabric, is heated to a molten state and the latex is made cools as long as the fleece is kept under tension « 109835/1 £ 52