EP0822283A2 - Nonwoven fabric and device for making the same - Google Patents

Abstract

A spun-bonded web comprises two types, (a) and (b), of bi-component filaments of the same titre where the core material (1), polyethylene terephthalate, has a higher melting temperature than that of the sheath material (2), a binding polymer material. The ratio by weight of the sheath material of type (a) filament to type (b) filament, 2a:2b, is in the range 1:3 - 1:10 and over a cross-section of the web, the ratio by weight of type (a) filaments to type (b) filaments varies from 15 to 70%. This latter ratio changes through the cross-section planes of the web without noticeable phase boundaries. Also claimed is the apparatus for producing the web.

Description

The invention relates to a spunbonded nonwoven, which in the course of its Different cross-sectional contents of type A bicomponent fibers and B.

Such a spunbonded nonwoven 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 exists from the polymer components (a1) and (a2), the latter one around 30 ° C. has a higher melting point than (a1). Filament type B consists of the polymer components (b1) and (b2), component (b1) being around 20 ° C. higher melting point than component (a1) and being the component (b2) a melting point which is more than 30 ° C. higher than that of component (b1) having.

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 provide a spunbonded nonwoven fabric made of core / sheath bicomponent filaments with a hard core and with a lower temperature to indicate as this core melting coat, the inside of which, as a result of different distribution of these filaments in the nonwoven cross section, softer or is designed to be harder than at least one of its outwardly facing ones Surfaces. These differences should not be reflected in a layer structure express with concrete phase boundaries to avoid the risk of delamination of the individual layers, e.g. after heat treatment during dyeing and vapors, or due to mechanical stress, e.g. when deforming, to exclude. Therefore, a very soft, flowing gradation of the Binding component concentration and thus the filament binding or adhesiveness can be generated over the cross-sectional profile of the nonwoven.

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.

Fig. 1 zwei Typen a und b von Bikomponentenfilamenten mit jeweils einem hoch schmelzendern Kern 1 und einem niedriger als dieser Kern schmelzenden Mantel 2. Typ a und b stehen einander, bei gleichem Filament-Titer, bezüglich des Gewichtes der Mantelkomponente im Verhältnis 2a:2b von 1:3 bis 1:10 gegenüber;

Fig. 2 unterschiedliche Anordnungen der Spinnstellen zum bewegten Auffangband und

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

To illustrate the invention, FIGS. 1 to 3 are only to be understood as examples. Show

Fig. 1 two types a and b of bicomponent filaments, each with a high-melting core 1 and a lower than this core melting shell 2. Types a and b are, with the same filament titer, in relation to the weight of the sheath component in the ratio 2a: 2b from 1: 3 to 1:10 compared;

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.

The explanations about the respective melting behavior of the bicomponent filaments formed core and cladding materials 1 and 2 understand each other assuming the use of the same melting point measurement methods for materials 1 and 2 (Fig. 1).

First, Fig. 1 is considered. There are two core / shell bicomponents Filament types a, b shown as used according to the invention. With 1 the core is made of polyethylene terephthalate, with 2 the jacket from the binding Component called. Filaments with such cross sections and their Spinning through nozzles from the melt are known per se and not Subject of the invention.

Examples of binding components 2 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.

As already mentioned, the weight ratio of the jacket components is 2a: 2b according to the invention from 1: 3 to 1:10, in each case with the same titer of the filaments of type a and b.

The invention relates to a spunbonded nonwoven fabric, which consists of these two Types a and b of core / sheath filaments exist and which over his Cross-sectional profile different contents of these bicomponent filaments , the content of type b filaments between 15 and 70 % By weight, based on the weight of the respective cross-sectional plane of the nonwoven.

It is essential to the invention that the individual cross-sectional planes of the spunbonded nonwoven, what different proportions of bicomponent filaments a, b have, sliding with respect to these contents, without recognizable phase boundaries, merge. Therefore, delamination of contiguous Nonwoven layers with different filament compositions so almost impossible.

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 use of the nonwoven, the rule must be observed become that softer contents of type b bicomponent filaments and more flexible nonwoven surfaces, while in extreme cases the Presence of this type of filament to 70 wt .-% an internal stability of the Nonwoven surface is achieved, which they as a carrier and stabilizer of the whole Nonwoven construction makes it suitable. These latter have nonwoven layers also a barrier function against the passage of fluid media, what Filtering applications is important; the binding jacket components of the individual filaments have flowed into one another and form one for the fluid Barrier.

A preferred variant of the invention is that one to the outside facing surface of the spunbonded nonwoven a higher proportion of the filament Type b has and is both hard and hot-adhesive compared to the opposite surface facing the other outside, which is soft with a lower proportion of these filaments and only in interrupted ones Surface areas has hot-melt adhesive properties.

The hot-tack ability with high proportions of type B filaments is another Advantage of the inventive design of the spunbonded nonwoven and important especially for textile applications, e.g. Stiffening inserts. Of the Cross-section of such a nonwoven fabric has a constant gradient of percentage of bicomponent filaments of type a or b and hence the hardness from one surface to another.

Another application example for this aforementioned variant, in which the hard surface of the nonwoven fabric 70% by weight of bicomponent fibers type b, relates to the manufacture of tufted carpets:

The gradient towards the hard, binding component 2 is sufficient Surface prevents this when foam coating such carpets Penetration of the coating mass from the soft surface side up to 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 filaments of type b, has outer surfaces compared to its inner cross-sectional areas which are harder in this regard, since there are a larger number of bicomponent filaments b is present.

The invention also includes a spunbond nonwoven variant in which the a relatively high bicomponent filament proportion on each of the two outwardly facing surfaces type b and therefore have a hard consistency exhibit. The inner cross-sectional areas are against it, with lower ones Filament b proportions, very soft.

Allow both of the latter variants with similar outer surfaces the manufacture of fabrics which, in the case of low filament proportions b 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. Under the stretching device the spun filaments fall onto a transport device, the essential component of which is a horizontally and linearly moving catch belt 7, on the surface of which the filaments hit and to Spunbonded nonwoven.

The spinning holes 5 serve to discharge the core / sheath filaments of type a, the spinning holes 6 the discharge of the core / sheath filaments of type b, respectively from their melting. Both types of spinning holes 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 two filament types a and b hitting the moving one Safety belt 7 in a predetermined time and, in terms of area of the fall arrester 7, linear sequence happens. The device is for this Purpose designed so that the projection of all spin holes 5, 6 of the inserted Spinning plates 3 or spinning disks 4 in their entirety on the Level of the collecting belt 7 the concentration curve of the filament mixture in the vertical cross section of the nonwoven. Towards the movement seen the catchment belt 7, so hits that filament mixture first on which one of the exterior surfaces of the to be manufactured Form nonwoven. Then arrive in the smooth transition of the first filed type and mixture of filaments that the inner Areas of the non-woven filaments or mixtures to be deposited until Finally, the filament mixture that hits the belt 7 is the second Surface of the spunbonded nonwoven is to form.

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 3a of the spinning holes 5, 6 on the spinneret plate 3 leads to a spunbonded nonwoven whose one surface, which is first deposited on the belt 7 increases filaments of the Type a from the spinning holes 5 contains and is very soft. With increasing Storage time becomes constant with this, the collecting belt 7 facing surface higher proportions of type b bicomponent filaments from the spinning holes 6 covered. Finally the other surface of the spunbonded nonwoven is created which mostly contains filaments of type b and a corresponding one Hardness and rigidity.

If one or more spinneret plates 3 according to FIG. 3b are used, then According to the above teaching, a spunbonded nonwoven is created with a catch belt facing, mostly containing type b bicomponent filaments Surface created by the spinning holes 6, which in the upper in the drawing Part are arranged on the spinneret plate 3 in the plurality. With increasing Operating time of the device within one workflow the inner cross-sectional areas of the nonwoven are increased from type a filaments formed (middle part of the spinneret plate 3, spinning holes 5). Due to continuous, increasing depletion of type a filaments finally the second surface.

A spunbonded nonwoven can be built up with a device according to FIG. 3c, which on the surface facing the collecting belt 7 filaments of Type a in an amount up to 85 wt .-% and in which further Cross-sectional profile up to the inside the filament portion of the Type b grows up to 70% by weight. The surface facing away from the collecting belt 7 the nonwoven is then again made from 85% by weight core / sheath filaments of type a, rest = type b.

In addition, Fig. 3d is considered in this context, which of 3a corresponds, with only the spinneret plate 3 here is aligned transversely to the running direction of the catch belt 7 and their The longitudinal axis corresponds to the length of the nonwoven fabric width to be produced. This Variant is shown again in FIG. 2a and there, above, referred to 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 lined up to each other transversely to the running direction are, as shown in Fig. 2a, variant a1. Analogous to this are the Spinning disks 4 according to variant a2 in Fig. 2a on an imaginary line arranged transversely to the running direction of the catch belt 7 to each other.

In the variants in Fig. 2, a1 and a2, it is necessary that between the spinneret plates 3 or spinning disks 4 and the catch belt air flows the filament groups leaving the spinning holes 5, 6 transverse to their Fall direction and transverse to the running direction of the collecting belt 7 or the longitudinal axis of the spinneret plates 3 pivot in order to cross to said Direction of rotation to obtain a homogeneous nonwoven cross section. This technology the swiveling leading air flows is state of the art and can for most existing devices, if not already available, can be easily 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 filament blend 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 core / sheath filaments made of different materials have to be changed.

The invention can therefore on existing systems by the lowest possible Conversion measures are carried out, whether these systems for cross or Spinneret plates aligned along the direction of the collecting belt or spinning discs are designed or whether a correspondingly oblique arrangement of spinneret plates the concept of the available device underlying.

Claims (8)

Spunbonded nonwoven, consisting of two types (a) and (b) of core / sheath bicomponent filaments same title and with one at higher temperature than the shell material (2) melting core material (1), the weight ratio of the shell materials (2) of Type (a) and type (b) filaments, 2a: 2b, 1: 3 to 1:10, which is Core material (1) made of polyethylene terephthalate and the cladding material (2) consists of a polymeric, binding material, with the Cross-sectional course of the spunbonded nonwoven different weight ratios between filament types (a) and (b) in the range from 15 to 70% by weight of type (b) filaments and the different Weight ratios of cross-sectional planes having filaments (a) and (b) of the spunbonded nonwoven with no discernible phase boundaries merge. Spunbonded nonwoven fabric according to claim 1, characterized in that a its outward-facing surfaces have a higher bicomponent filament content of type (b) and is both hard and hot-adhesive compared to the second one, is to the other outside facing surface, which with a lower bicomponent filament (b) content is soft and not hot-tacky. Spunbonded nonwoven fabric according to claim 1, characterized in that it has two soft, relatively small proportions of filaments of type (b) has outward-facing surfaces and that its interior formed harder than these outer surfaces and with a greater number of filaments of type (b) than on these surfaces is provided. Spunbonded nonwoven fabric according to claim 1, characterized in that its two outward-facing surfaces with a high proportion of filaments of type (b) are hard and their interior, with a lower filament (b) content, compared to these surfaces, soft is. Device for producing a spunbonded nonwoven, which has the characteristics of claim 1, wherein this device is one to 40 rectangular Has spinneret plates (3) or round spinning disks (4), which leave over a stretching device for 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 (5) on each spinneret plate (3) or spinning disc (4) the core / sheath filaments of type (a) and other spinning holes (6) the core / sheath filaments of type (b) from the melt eject that, seen in the direction of the catch belt (7), the Sequence and arrangement of the individual filament types Spinning holes (5), (6) is such that their projection in its entirety on the level of the collecting belt (7) the concentration curve of the filament mixture corresponds in the vertical cross section of the nonwoven, whereby, viewed in the direction of movement of the catch belt (7), the one Filament blend first hits which one of the outside to form facing surfaces of the nonwoven, whereupon, in the smooth transition from the first filaments that are deposited inner areas of the nonwoven filament mixtures for storage arrive and in the end also the other one pointing outwards Surface of the nonwoven filament mixture in the flowing Transition to the previously stored mixture is stored. 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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