EP0822284A2 - Nonwoven fabric and device for making the same - Google Patents

Abstract

A spun-bonded web comprises monofilaments of polyethylene terephthalate and bi-component filaments of polyethylene terephthalate and a binding polymer material in the form of at least two externally facing segments (2), the content by weight of bi-component filaments varying over the web cross-section from 1 to 100%. This ratio changes through the cross-section planes of the web without noticeable phase boundaries. Also claimed is apparatus for producing the web. It comprises 1 to 40 rectangular spinneret plates (3) or circular discs placed above a drafting device for the filaments leaving the spinneret holes (5), (6), where some holes (5) eject bi-component filaments and others (6) mono-filaments from the smelt. Below the drafting device is a horizontally moving collecting belt on which plane, as viewed in the travel direction, the filaments are projected in an arranged sequence which corresponds to the concentration gradation of the filament mixture in vertical cross-section. I.e. a filament mixture is first laid down which forms an externally facing web surface, subsequently internal web layers are formed in sequence and finally the other externally facing surface layer, all smoothly merging one with another.

Description

The invention relates to a spunbonded nonwoven, which in the course of its Cross-section has different contents of bicomponent filaments. The remaining filaments are polyethylene terephthalate monofilaments. Such a Spunbonded nonwoven fabric is known as a material from JP-A-Patent 435 28 61 for sacks:

The spunbonded non-woven fabric consists of two types A and B of long, conjugated Multi-component filaments. Filament type A consists of the polymer components (a1) and (a2), the latter having a melting point which is 30 ° C. higher than (a1). Filament type B consists of the polymer components (b1) and (b2), component (b1) having a melting point which is 20 ° C. higher than component (a1) and wherein component (b2) has a more than 30 ° C higher melting point than component (b1).

The nonwoven also has a four-layer structure in cross section, wherein the individual layers differ in that the first only filaments of type A, the second and third layers contain filament types A and B with a higher proportion of A in the second and a higher proportion filament type B in the third layer, while the fourth Layer consists only of type B filaments.

The different melting points resulting from this structure the two surfaces of the nonwoven and different melting points in the cross-section of the nonwoven fabric prevent delamination of the individual layers.

The object of the invention is to produce a spunbonded nonwoven made of mono- and bicomponent filaments indicate its interior, due to the different Distribution of these filaments in the non-woven cross-section, softer or harder is as at least one of its outward-facing surfaces. These differences should not be reflected in a layer structure with concrete Express phase boundaries to reduce the risk of delamination of the individual layers, e.g. after heat treatment during dyeing and steaming, or due to mechanical stress, e.g. when deforming.

The invention further relates to a for producing such a spunbonded nonwoven suitable device which, in contrast to the prior art Technology where several separate process steps for Manufacture and required to connect the individual layers of the nonwoven and each of these stages is a separate, customized arrangement of Has spinneret bars, a single device with correspondingly arranged Spinneret beam is sufficient, and this arrangement of those on conventional devices for the production of monofilaments equal.

The solution to this task is the higher-level product and device requirements spelled out. Advantageous configurations for this are by the associated subclaims marked.

To clarify the invention, these are only to be understood as examples Figures 1 to 4 used.

Fig. 1 mögliche Querschnitte der Bikomponentenfilamente;

Fig. 2 unterschiedliche Anordnungen der Spinnstellen zum bewegten Auffangband und

Fig. 3 verschiedene Varianten von Spinnloch-Anordnungen auf rechteckigen Spinndüsenplatten.

Show

1 possible cross sections of the bicomponent filaments;

Fig. 2 different arrangements of the spinning positions for moving the catcher and

Fig. 3 different variants of spinning hole arrangements on rectangular spinneret plates.

For better understanding, these figures are preceded by a list of reference symbols.

Segmente" soll hier verstanden werden eine regelmäßig oder unregelmäßig geformte Anreicherung der bindenden Komponente auf der Außenfläche eines bzgl. seines Querschnittes beliebig gestalteten Polyethylenterephthalat-Kernfilaments.First, Fig. 1 is considered. Three variants a, b, and c are shown there by way of example for cross sections of bicomponent filaments as are used according to the invention. The filament matrix made of polyethylene terephthalate is denoted by 1, and 2 each denotes an outward-pointing segment from the binding component. Filaments with such cross sections and their spinning through nozzles from the melt are known per se and are not the subject of the invention. Under

Segments "should be understood here to mean a regularly or irregularly shaped enrichment of the binding component on the outer surface of a polyethylene terephthalate core filament of any cross-section.

Examples of adhesive components are copolymers of terephthalic acid or dimethyl terephthalate, isophthalic acid, adipic acid, ethylene glycol, butanediol, and homopolymers such as polybutylene terephthalate, polyamides and polyolefins the homologous range from polyethylene to polybutylene.

The invention relates to a spunbonded nonwoven fabric, which consists of mono- and Bicomponent filaments exist and which over its cross-sectional course has different contents of bicomponent filaments, where these contents between 1 and 100 wt .-%, based on the weight of each selected cross-sectional plane of the nonwoven.

The monofilaments which may be present consist of polyethylene terephthalate, the bicomponent filaments made of a core made of polyethylene terephthalate, which comprises the mentioned, outwardly facing segments 2 of the binding component. Essential to the invention is in particular that the cross-sectional planes of the spunbonded nonwoven, which have different proportions on bicomponent filaments, sliding with respect to these contents, without recognizable phase boundaries, merge into one another. Hence delamination of adjacent nonwoven layers with different filament compositions almost impossible.

The invention allows a large number of percentage metering of the filaments in the individual cross-sectional planes. A large number of spunbonded nonwovens can thus be produced, and basis weights of 10 to 500 g / m ² can be produced as desired.

Depending on the desired application of the nonwoven, the rule must be observed be that low levels of bicomponent filaments to softer and lead to more flexible nonwoven surfaces, while in extreme cases the exclusive The presence of these filaments ensures an internal stability of the nonwoven surface is achieved, which they as a carrier and stabilizer of the entire nonwoven structure makes suitable. These latter have nonwoven layers also a barrier function against the passage of fluid media, what for filter applications is important.

A preferred variant of the invention is that one to the outside facing surface of the spunbonded nonwoven has a higher bicomponent filament content possesses and is both hard and hot-adhesive compared to the opposite surface facing the other outside, which is softer with a lower bicomponent filament content and has no hot-melt adhesive properties. This hot tack at high Bicomponent filament proportions is another advantage of the invention Design of the spunbonded nonwoven and important especially for textiles Applications such as Stiffening inserts. The cross section of such Nonwoven has a constant gradient of the percentage on bicomponent filaments and thus also the hardness of one surface to the other.

Another application example for this variant, in which the hard Surface of the nonwoven contains 80 to 100% of bicomponent fibers the production of tufted carpets:

The gradient in the direction of the hard surface rich in bicomponent fibers prevents streaking when foaming such carpets the coating mass from the soft surface side up to the pile fibers. This gradient also indirectly controls the tear resistance of the finished carpet.

In contrast, the voluminous and soft nonwoven side promotes the good one Pimples and thus anchoring of the carpet fibers in the nonwoven cross section when tufting.

Furthermore, the tufting needles can be inserted into the nonwoven fabric from the hard side penetrate without loosened fibers from it in the needles and disrupt the tufted image.

The fourth advantage for the application for tufted carpets is that in is able to with low carpet fiber weights (pile weights) and carpet fiber lengths (Pole heights) to work without changing the surface image (Pole image) through fibers detached from the nonwoven composite is caused.

Another preferred embodiment of the invention relates to a spunbonded nonwoven, which has two soft, few bicomponent filaments, has outer surfaces compared to its inner cross-sectional areas which are harder in this regard, since there is a larger one Number of bicomponent filaments is present.

The invention also includes a spunbond nonwoven variant in which the a high proportion of bicomponent filament on both surfaces facing outwards possess and thus have a hard consistency. The inner cross-sectional areas are against it, with lower bicomponent filament proportions, very soft.

Allow both of the latter variants with similar outer surfaces the production of fabrics that, in the case of low bicomponent proportions outside, have a very textile handle on both sides, or which, in the alternative with hard outer surfaces and soft inner core, have a large volume with high air permeability. This property is useful, for example, for air filters, their outer surfaces only have to contribute to the load-bearing capacity and strength. It is also in the manufacture such filter is advantageous if, despite the softness of the material the processing of which does not result in fibers detaching from the structure.

The invention also relates to a device for producing the first product claim characterized spunbonded nonwoven.

Referring to Figs. 2 and 3, this device has one to forty rectangular spinneret plate (s) 3 or round spinning disc (s) 4, which over a conventional stretching device (not shown) for the Spinning holes 5, 6 leaving filaments is (are) arranged. Below the Stretching device, the spun filaments fall onto a transport device, whose essential component is a horizontally and linearly moving Catch tape 7 is, on the surface of which the filaments hit and to Spunbonded nonwoven.

The spinning holes 6 serve to discharge the monofilaments, the spinning holes 5 the discharge of the bicomponent filaments, each from their melt. Both Spinning hole types 5, 6 are on each spinneret plate 3 or spinning disc 4 available.

According to the invention, the areal distribution of the spinning holes 5, 6 to each other in such a way that, seen in the running direction of the catch belt 7, the Sequence of the occurrence of the two types of filament, polyethylene terephthalate and Bicomponent filaments, on the moving catch belt 7 in a predetermined temporal and, with respect to the area of the catch belt 7, linear Sequence happens. For this purpose, the device is designed such that the projection of all spin holes 5, 6 of the spin plates 3 or Spinning disks 4 in their entirety to the level of the fall arrester 7 Concentration course of the filament mixture in the vertical cross section of the Nonwoven corresponds. Seen in the direction of the movement of the catch belt 7, so hit those filaments or that filament blend first on which one of the outer surfaces of the to be manufactured Form nonwoven. Then arrive in the smooth transition from the first filed type and blend of filaments covering the inner areas the filaments or blends forming the nonwoven to be deposited until the very end hit those filaments on the belt 7 which are the second surface of the spunbonded nonwoven.

According to the above, FIG. 3 shows three in the upper half with their Longitudinal axis arranged parallel to the running direction of the collecting belt 7 rectangular spinneret plates 3. The arrangement a of the spinning holes 5, 6 on the spinneret plate 3 leads to a spunbonded nonwoven whose one surface, which is first placed on the belt 7, is very soft and exclusive Contains monofilaments from the spinning holes 6. With increasing Storage time becomes constant with this, the collecting belt 7 facing surface higher proportions of bicomponent filaments from the spinning holes 5 covered until the other surface of the Nonwoven fabric is deposited, which is made entirely of bicomponent filaments Spinning holes 5 exists and thus a higher hardness and rigidity than that first generated area and the property of hot-melt adhesive properties.

If one or more spinneret plates 3 are used according to variant b in Fig. 3, a spunbonded nonwoven with a Collection belt facing exclusively containing bicomponent filaments Surface created by the spinning holes 5, which in the drawing the upper part on the spinneret plate 3 are arranged. With increasing operating time the device, the inner cross-sectional areas of the Nonwoven fabric formed from the monofilaments alone (middle part of the spinneret plate 3, spinning holes 6). Through continuous transitions to the shelf a mixture of both filament types and then their increasing depletion the second surface, which is created on monofilaments corresponding to the lower region of the spinneret plate 3 exclusively Bicomponent filaments is constructed.

With variant c, a spunbonded non-woven fabric can be built up on the Collection surface 7 facing surface almost exclusively monofilaments contains and in which in the further cross-sectional course to the inside the bicomponent filament content is continuously growing up to 100%. The one Harness 7 facing away from the nonwoven surface is then exclusive again formed from monofilaments.

In addition, variant d, which of variant a corresponds, with only the spinneret plate 3 transverse to the direction of the Harness 7 is aligned and its longitudinal axis is the length of the generating nonwoven width corresponds. This variant is again in Fig. 2a shown and designated as a3.

It is also possible to use several rectangular spinneret plates 3 or round ones Arrange spinning disks 4 in series to each other, whereby, in the running direction of the Collection belt 7 seen, the longitudinal axes of the spinneret plates 3 parallel to this running direction and the plates 3 are lined up transversely to the running direction, as shown in Fig. 2a, variant a1. The spinning disks are analogous to this 4 according to variant a2 on an imaginary line transverse to the running direction of the collecting belt 7 arranged to each other.

With variants a1 and a2 it is necessary that between the Spinneret plates 3 or spinning disks 4 and the air flow catch belt the filament shares leaving the spinning holes 5, 6 transverse to their direction of fall and transverse to the running direction of the catch belt 7 or the longitudinal axis of the spinneret plates 3 pivot to run transversely to said direction to obtain a homogeneous cross-section of nonwovens. This technology The swiveling leading air flows are state of the art and can be used with the most existing devices, if not yet available, easily be retrofitted.

Another variant of the device looks obliquely to the transport direction of the Harness 7, staggered in a row parallel to its level arranged, rectangular spinneret plates 3, as in two variants b1 and b2 is shown in Fig. 2b. With this graduation they are also the ones Spinning holes 5, 6 leaving filaments transversely to their direction of fall and transversely to lead to the running direction of the collecting belt 7 pivoting through air currents, to maintain a constant blend of fibers within each level of the nonwoven to obtain.

The large number of possible arrangements of the spinning devices 3, 4 shown here with regard to the catch belt 7, of which Fig. 2 only a few useful examples Shows possibilities offers the great advantage that the invention Device in an extremely simple way in existing system systems can be installed for spinning monofilaments: only the configuration of spinning holes 5 and 6 as well as the processing and distribution system for the melt for the separate production of filaments different materials have to be changed. The invention can So on existing systems through the least possible conversion measures be carried out, regardless of whether these systems for transverse or longitudinal to the direction spinning nozzle plates or spinning disks aligned with the catch belt are designed or whether a correspondingly oblique arrangement of spinneret plates the concept of the available device lies.

Reference list

1

Filament core made of polyethylene terephthalate

2nd

Binding component segment

3rd

rectangular spinneret plate

4th

round spinning disc

5

Spinning hole for a bicomponent filament

6

Spin hole for a monofilament

7

Fall arrester

Claims (8)

Spunbonded fabric consisting of mono- and bicomponent filaments, with different contents of bicomponent filaments across its cross-section, the monofilaments made of polyethylene terephthalate and the bicomponent filaments made of polyethylene terephthalate and a polymeric, binding component, characterized in that that the bicomponent filaments after at least two have externally facing segments (2) of the binding component, that differ over the cross-sectional course of the spunbonded nonwoven Contents of bicomponent filaments are 1 to 100% by weight and that the different proportions of bicomponent filaments Cross-sectional planes of the spunbonded nonwoven without recognizable Merge phase boundaries. Spunbonded nonwoven fabric according to claim 1, characterized in that a its outward-facing surfaces have a higher bicomponent filament content owns and is both hard and hot-adhesive, compared to the second, facing the outside Surface that is soft with a lower bicomponent filament content and is not hot-stick. Spunbonded nonwoven fabric according to claim 1, characterized in that it has two soft, relatively small amount of bicomponent filaments inside has outward-facing surfaces and that its interior is made harder than these surfaces and with a larger one Number of bicomponent filaments than on these surfaces is provided. Spunbonded nonwoven fabric according to claim 1, characterized in that its two outward-facing surfaces with a high bicomponent filament content are hard and its interior, with a lower bicomponent filament content, compared to these surfaces, softer is. Device for producing a spunbonded nonwoven, which has the characteristics of claim 1, wherein this device 1 to 40 rectangular Has spinneret plates (3) or round spinning discs (4), which over a stretching device for those leaving the spinning holes (5), (6) Filaments are arranged, being under the stretching device a transport device with a horizontal and linear Moving catch belt (7) for the filaments and where the Spinneret plates (3) or round spinning discs (4) to the catch belt (7) pointing spinning holes (5), (6), characterized in that that spinning holes (6) on each spinneret plate (3) or spinning disc (4) the monofilaments and other spinning holes (5) the bicomponent filaments eject from the melt that, in the direction of the Catchment belt (7) seen the sequence and arrangement of each Filament types ejecting spinning holes (5), (6) is such that their Prolection in its entirety on the level of the fall arrester (7) the concentration curve of the filament mixture in the vertical cross section of the nonwoven corresponds, whereby, in the direction of the movement of the Seen the collecting belt (7), that filament mixture hits first, which form one of the outward-facing surfaces of the nonwoven fabric is said to be, then, in the smooth transition from the first deposited filaments that form the inner areas of the nonwoven Filament mixtures arrive at the filing, and in the end as well the other facing surface of the nonwoven fabric Filament blend in the smooth transition to the previously deposited blend comes to storage. Apparatus according to claim 5, characterized by at least one transversely to the transport direction of the catch belt (7), which too Rectangular spinneret plate corresponding to the width of the nonwoven fabric (3). Device according to claim 5, characterized by several in series mutually arranged, rectangular spinneret plates (3) or round ones Spinning disks (4), the line-up in each case transverse to the transport direction of the catchment belt (7) is applied, with the Spinneret plates (3) or spinning disks (4) and the Catchment belt (7) are each devices generating air currents and these air streams leaving the spinning holes (5) and (6) Filament shares across their direction of fall and across the direction of travel of the collecting belt (7) or transversely to the longitudinal axis of the spinneret plates (3) pivot. Apparatus according to claim 5, characterized by several obliquely to the direction of transport of the catch belt (7) and parallel to it Rectangular spinneret plates arranged in a staggered plane (3), being between the spinneret plates (3) and the Safety belt (7) devices generating air currents are located and these air currents leaving the filament holes (5) and (6) transverse to the direction of their fall and transverse to the direction of the Collection belt (7) or the longitudinal axis of the spinneret plates (3) lead swinging.

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