WO2016165835A1

WO2016165835A1 - Nonwoven layer for heat protection textiles

Info

Publication number: WO2016165835A1
Application number: PCT/EP2016/025033
Authority: WO
Inventors: Marc Jolly; Stuart Smith; André Lang; Andy SCHUFFENHAUER
Original assignee: Norafin Industries (Germany) Gmbh
Priority date: 2015-04-15
Filing date: 2016-04-08
Publication date: 2016-10-20
Also published as: DE102015004841A1

Abstract

The invention relates to a nonwoven layer (1) for heat protection textiles having a fibre composite (4) which is provided at least partly from inherently flame-retarding fibres, wherein the nonwoven layer (1) has a multiplicity of air spaces (5) that are distributed in its surface directions (7) for thermal insulation, said air spaces (5) each extending over at least 1 mm in the thickness direction (2) perpendicular to the surface directions (7) of the nonwoven layer (1) but only passing through part of the nonwoven layer (1) in the thickness direction (2), and wherein a multiplicity of holes (6) have been introduced into the nonwoven layer (1) in addition to the air spaces (5), said holes (6) extending into the nonwoven layer (1) in the thickness direction (2) from one side (3) of the nonwoven layer (1) and each having an opening cross-sectional area of at least 1 mm² and at most 15 mm² in the surface directions (7).

Description

Nonwoven fabric layer for heat protection textiles

The present invention relates to a nonwoven fabric layer for heat protection textiles.

Heat protection textiles can be used, for example, in protective clothing, such as protective jackets and trousers for firefighters. The heat protection properties can be evaluated according to the NFPA 1971 standard with the so-called TPP value {Thermal Protective Performance). A minimum requirement for garments according to the NFPA standard, for example, corresponds to a TPP value of 35, in which under direct fire (flashover) for a period of 17 Vi seconds, protection against second-degree burns must be present.

The present invention is based on the technical problem of specifying a particularly advantageous nonwoven layer for heat protection textiles and an advantageous method for the production thereof.

According to the invention, this object solves a nonwoven fabric for heat protection textiles with a fiber composite, which is at least partially provided by inherently flame retardant fibers, the nonwoven fabric lying distributed in their surface directions for thermal insulation has a plurality of air spaces, which would be perpendicular to the surface directions of the nonwoven fabric Thickness direction extending over at least 0, 1 mm, the nonwoven fabric layer but only partially enforce in the thickness direction, and wherein in the nonwoven fabric Läge in addition to the air spaces a plurality of holes are introduced, extending from a side surface of the fiber composite, preferably at the same time side surface of the Nonwoven fabric layer is in the thickness direction extending into this and thereby have a respective opening cross section of at least 1 mm ² and at most 15 mm ² in the surface directions.

Preferred embodiments can be found in the dependent claims and the entire disclosure, wherein the representation does not always differ in detail between device and process or use aspects. that will; In any case, implicitly, the disclosure must be read with regard to all categories of claims.

The nonwoven fabric layer according to the invention is thus structured in two ways, namely on the one hand with the at least primarily the thermal insulation serving air spaces. If one side of the nonwoven fabric is exposed to heat or, more generally, heat / heat, the air spaces will at least delay a critical increase in temperature on the other side of the nonwoven fabric layer. The nonwoven fabric layer according to the invention is therefore optimized, on the one hand, for a good TPP value of the garment produced therefrom, which, for example, based on the nonwoven fabric layer, has a value of at least 0.01, 0.05, 0.1, 0 taken in m ² s / g , 15 or 0.2 may mean; possible upper limits may be around 1, 0.5 and 0.3, respectively. The unit is the same as mentioned above, but the values given here refer to one layer, not to the garment (multi-layered).

On the other hand, as the second structure, in addition to the air spaces, the plurality of holes are introduced into the nonwoven fabric layer, which can improve their breathability. To stick with the example of firefighters, lack of breathability can lead to heat build-up under clothing, which can put a strain on the body and in the worst case can lead to unconsciousness or even heart problems. A measure of this may be the so-called Total Heal Loss (THL) value according to the NFPA 1971 standard (updated last 2013), which characterizes the ability to dissipate heat. With the nonwoven fabric layer according to the invention, for example, THL values of at least 500 W / m ² , 750 W / m ² , 1,000 W / m ² , 1,250 W / m ² and 1,500 W / m ² can be achieved; Possible upper limits may, for example, at not more than 2,000 W / m ^2, are 1,750 W / m ² and 1500 W / m ^2.

The inventors have found that the holes improve the THL value and, surprisingly, at least do not significantly degrade the TPP value. To put it simply, there is a conflict of interest in that with regard to the heat / fire effect from one side (outside in Regarding the garment) a good insulation is desired, but nevertheless heat is to be dissipated from the inside to the outside.

A current working hypothesis as to why the holes improve the THL value, but on the other hand worsen the TPP value by at least the same factor, is that different time scales play a role here. In simple terms, the processes relevant for the TPP value are dynamic processes because of the comparatively short time scales, whereas the THL value can determine equilibrium states in which, for example, convection can be established through the holes from the inside to the outside ( the air holes create a certain air permeability), conversely the time duration in the case of the TPP value is too short. But, as I said, this is currently only a working hypothesis; In any case, it is surprising that TPP and THL values can be improved with the holes as described at the same time.

The air holes can, for example, help to transport water vapor and thus heat away from the body due to a capillary effect. With the proposed, twofold structure, it may also be possible to submit advantages relating to wearing comfort {wearability). For example, the holes can provide a wearability comparable to a fabric, which can not be achieved with a closed structure.

Apart from the holes, the air spaces only partially penetrate the nonwoven fabric layer in the thickness direction, so that the fiber material (the fiber composite) of the nonwoven layer follows the air spaces in the thickness direction toward at least one side of the nonwoven fabric layer. In other words, the airspaces do not extend completely through the nonwoven fabric layer. On the other hand, however, they each have a minimum height (taken in the thickness direction) of 0.1 mm, with at least 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1, 1 mm, 1, 2 mm or 1, 3 mm further, in the order of naming increasingly preferred lower limits are; independently of this, advantageous upper limit zen. For example, in this order increasingly preferred at most 5 mm, 4.5 mm, 4 mm, 3.5 mm, 3 mm, 2.5 mm or 2 mm.

Relative to a thickness of the nonwoven fabric layer taken perpendicular to their surface directions, the air spaces may each extend over, for example, at least 10%, in this order increasingly preferably at least 20%, 30%, 40% or 50%, of the nonwoven fabric layer thickness, wherein (independently thereof ) maximum limits, for example, at most 90%, in this order increasingly preferably at most 80%, 70% and 60%, respectively. Regardless of whether absolute or relative values are considered, the extent of a respective air space in the thickness direction is considered in each case its maximum extent; The holes are neglected, so it is assumed that a (theoretically) hole-free fiber composite.

The thickness of the nonwoven fabric layer is taken between two tangential planes, which are respectively placed tangentially and surface parallel to the fiber composite of the nonwoven fabric layer. Thus, if a side surface of the fiber composite is preferably shaped with a topography (see below in detail), the tangential plane is (theoretically) located on this topography. Each of the two mutually opposite side surfaces of the fiber composite can be correspondingly associated with a tangent plane (mental). A respective "side surface of the fiber composite" is that outer surface thereof which is visually viewable along a respective thickness direction on the fiber composite The aforementioned tangent planes are also referred to as "side surfaces" or "sides" of the nonwoven layer the nonwoven fabric layer with its side surfaces in each case to a further layer The nonwoven fabric layer is the entire layer between the two tangent planes.

The holes each have (in the surface directions) an opening cross section of at least 1 mm ² , in this order increasingly preferably at least 2 mm ² , 3 mm ² , 4 mm ² or 5 mm ² ; independently of this, advantageous upper limits are in this order increasingly preferably at most 15 mm ² , 14 mm ² , 13 mm ² , 12 mm ² , 11 mm ² or 10 mm ² . With corresponding holes, for example, the heat dissipation can be improved from the inside out, but the heat protection properties (external to internal) are not significantly affected. The respective "opening cross-section" of a respective hole / air space is taken in each case as an average value over the height, wherein the holes preferably have a constant opening cross-section over their height The hole cross-section ratio of hole to air space can, for example, be at most 1: 2, in this order increasingly preferably at most 1: 3, 1: 4, 1: 5, 1: 6, 1: 7, 1: 8, 1: 9 and 1:10, wherein (independently of) possible lower limits, for example. are at least 1: 100, 1:80, 1:60, 1:40, or 1:20 (increasingly preferred in the order in which they are mentioned). If the airspaces preferentially form a continuum (see below in detail), these numerical values should be given for the ratio hole opening cross section to web cross section (see below) be disclosed.

In general, the airspaces are identical to each other and the holes are identical to each other, but the holes differ from the airspaces. The "identity" refers at least to the opening cross-section, preferably also to the distance, correspondingly, the holes differ from the air spaces in opening cross-section and / or distance.The extent in the thickness direction can also be different, wherein, for example, the holes themselves also one another For illustration, with respect to the surface directions, each hole is delimited individually by the fiber composite, whereas the air spaces preferably form a continuum, ie, they are compressed fluidically together in the surface directions.

In general, in addition to the first structure (air spaces) and the second structure (holes) may also be provided a further structure, for example. A second plurality of holes extending from the first in their opening width and / or their distance and / or their output Side surface differ; Alternatively or additionally, for example, could also be provided second air spaces, which differ from the first in height and / or opening width and / or distance. Preferably, exactly two structures are provided, namely only the air spaces and the holes.

Generally, in the context of this disclosure, "plurality" refers to, for example, at least 100, in this order, more preferably, at least 500, 1,000, 2,000, 3,000, 4,000, or 5,000, corresponding units (air spaces or holes) per square meter, with (independently thereof) may be at most 500,000, 400,000, and 300,000, respectively.The reference to a "height" or "thickness" refers to the extent in the thickness direction, whereas a "width" is taken in either one of the surface directions.

The term "nonwoven fabric" refers to a consolidated nonwoven fabric / fleece, see the illustration below in detail The bonded fibers of the nonwoven fabric layer form a fiber composite In their fiber composite, apart from the air spaces / holes, the nonwoven fabric layer is a uniform, continuous layer. The fiber composite is a part held together by virtue of the fiber-fiber entanglement The fiber composite is, for example, a part held together binder-free (without binder), so long as the fiber composite is composed of several layers, these also hang without sewing / Bonding together, just because of the fiber-fiber entanglement For example, it is interspersed by each lying between the tangent planes, parallel to this level of fibers.

In a preferred embodiment, the holes extend as through-holes in the thickness direction respectively through the entire fiber composite of the nonwoven fabric layer, so they extend from one to the other side surface of the fiber composite. They may also open into a side surface of the nonwoven fabric layer in the air spaces and / or extend as far as the nonwoven fabric side surface (cf., FIG. 1 for illustration). In contrast, the airspaces do not completely enforce the fiber composite and the nonwoven fabric layer and, to that extent, they provide at least one-sidedly limited air cushion for insulation. The holes can allow a certain, limited air exchange between the mutually opposite side surfaces. In general, however, the holes do not necessarily extend through the entire fiber composite, but can also extend from one side surface of the fiber composite / nonwoven fabric layer only a little way into the fiber composite. Although they do not necessarily connect the opposing side surfaces directly (in the sense of a through-hole) pressure fluidically with each other, they can still allow a certain heat dissipation. Namely, the holes can locally reduce the "wall thickness" of the fiber composite between inside and outside (see Fig. 2 for illustration), that nevertheless a certain exchange can take place and, for example, water vapor can pass through.

It may generally be preferred that the air spaces are arranged within the nonwoven fabric layer insofar as they are limited (neglecting the holes) on both sides by the fiber material of the nonwoven fabric layer, ie the fiber composite. The holes then create towards at least one side surface, preferably to exactly one side surface, a pressurized fluidic connection into the air spaces.

In an alternative preferred embodiment, the air spaces are also apart from the holes, that is, if the holes did not exist, open to one side of the nonwoven fabric layer. The corresponding side surface of the fiber composite is thus formed with a plurality of elevations as topography; This topography in each case form free webs of the fiber composite, with the air spaces bounded, in each case towards this side surface. The ridges each have a height of at least 0.1 mm and a maximum of 5 mm away from the respective bottom of the respective recess formed therebetween in the thickness direction, for further preferred values, reference is made to the above disclosure on the height of the air spaces.

In general, "webs" formed from the fiber composite delimit the airspaces with respect to the surface directions, that is, to the side each extend to a side surface of the nonwoven fabric layer and so far each have a free end, cf. Figs. 1 and 2 for illustration. On the other hand, the webs can also be arranged within the nonwoven fabric layer in relation to the thickness direction, that is to say then pass into the other fiber composite with both ends. The webs then form, as it were, material bridges or columns within the fiber composite, cf. Fig. 3a, b for illustration. Now, either the webs or the laterally delimited airspaces may be connected with respect to the surface directions, the latter being preferred, being discrete as the webs in this respect (in certain sectional planes parallel to the tangential planes).

The discrete webs have in a preferred embodiment in the surface directions a respective, so per web taken, cross-sectional area of at least 20 mm ² , in this order increasingly preferably at least 100 mm ² , 300 mm ² , 500 mm ² , 700 mm ² , 900 mm ² , 1,100 mm ² , 1,300 mm ² and 1,500 mm ² , respectively; Advantageous upper limits are in this order increasingly preferably at most 3,000 mm ² , 2,800 mm ² , 2,600 mm ² , 2,400 mm ² , 2,200 mm ² and 2,000 mm ² , wherein the upper and lower limits in general may be independently of interest and should be disclosed in this form. The "cross-sectional area" of a respective web is taken as an average value over its height, whereby the holes remain out of consideration here, ie a (theoretically thought) structure free from the holes is considered.

In general, a regular arrangement of the air spaces or webs and / or holes is preferred, which refers to the arrangement in the surface, ie in the surface directions. The air spaces / webs / holes can thus be arranged obliquely, at right angles, centered-rectangular, hexagonal or square (in each case for themselves), that is to say in the form of a two-dimensional Bravais lattice. The "average distance" between the air spaces / webs / holes then results in each case as the mean value of the amount of the two base vectors spanning the respective unit cell (the amount is taken from each base vector and an average of the two amounts is formed) Basically, if the size of the two basis vectors is essentially the same, the smaller for example, after at least 50%, preferably at least 80%, particularly preferably at least 90%, of the larger; more preferably, the basis vectors are exactly the same in magnitude.

For this two-dimensional considerations so far, a vertical projection of the air spaces / lands / holes in one of the tangent planes is used. In this vertical projection, each air space / land / each hole then corresponds to an area, whereby the respective area centroid is then taken as the basis for the distance considerations. In the case of discrete airspaces, their projection is considered; in the case of discrete bridges their projection. In this vertical projection, the air spaces, webs or holes, for example, each have a round, in particular circular shape; it is also an angular shape possible, in particular an angular shape with straight side edges, such as an eight, six, five or square, in particular a rectangle, in particular a square.

In a preferred embodiment, the air spaces or webs have an average distance of at least 3 mm, preferably at least 4 mm, and of at most 40 mm, preferably at most 30 mm, particularly preferably at most 25 mm. The upper and lower limits may also be expressly of interest to one another and should also be disclosed in this form.

In a preferred embodiment, the holes have an average distance of at least 1 mm, preferably at least 2 mm, more preferably at least 3 mm, and at most 10 mm, preferably at most 8 mm, particularly preferably at most 6 mm, wherein the upper and lower limits in turn also independently of each other and should be disclosed in this form.

In general, the "inherently flame-retardant fibers" can be, for example, viscose FR, aramid (meta-aramid or para-aramid), polyimide (in particular polyimide / amide), polybenzyl, p-phenylene - 2 , 6-benzobisoxazole, phenol, melamine min, polyacrylate, polyacrylonitrile, oxidized polyacrylonitrile (Preox) - and / or polyphenylene sulfide fibers act. It can be provided both one of these individual fiber types as a single fiber and a mixture of several of these individual fiber types. Most preferably, the inherently flame retardant fibers comprise Preox fibers, either as a single fiber or in a blend. In general, the property "inherently flame-retardant" refers to fibers which are flame retardant due to their original material properties, which are therefore not given the flame retardant properties, for example, not only by a chemical aftertreatment (a protective film).

In a preferred embodiment, the inherently flame retardant fibers in the nonwoven fabric would be at least 40%, more preferably at least 50%, 60%, 70%, and 80%, respectively, in this order. In general, the nonwoven fabric (the fiber composite) may also be provided as a whole of inherently flame-retardant fibers, so the proportion is at 00%. The inherently flame-retardant fibers are preferably a mixture of at least two individual fiber types, each having a proportion of at least 20%, preferably at least 30%, particularly preferably at least 40%, of the mixture (the proportions refer to the inherently flame retardant fibers). Preferably, the mixture comprises preox and / or polyacrylate fibers, more preferably it consists of both.

The inherently flame retardant fibers of the nonwoven fabric layer preferably have a proportion of at least 40%, more preferably at least 50%, particularly preferably at least 60% Preox fibers. Preferably, the inherently flame retardant fibers of the nonwoven fabric layer comprise at least 20%, preferably at least 30%, polyacrylate fibers. Particularly preferably, the nonwoven layer consists exclusively of Preox and polyacrylate fibers. In general, the percentages in this context refer to a corresponding weight percentage. In a preferred embodiment, the nonwoven layer comprises at least 10%, preferably at least 20%, non-inherently flame retardant fibers. Preferred upper limits are at most 30%, preferably at most 25%. The non-inherently flame retardant fibers may be, for example, cellulosic, polyester, polypropylene, polyethylene, polyethylene terephthalate and / or bicomponent polyethylene fibers, the latter being preferred, such as polyethylene / polyethylene terephthalate (PE / PET) or polyethylene / polypropylene (PE / PP). A certain minimum content of non-inherently flame-retardant fibers may, for example, be advantageous insofar as at least some thermal hardening can then take place in the production, so that, for example, B. less mechanically solidified. This may be of interest in terms of a desirable because of the thermal insulation properties, the largest possible thickness of the nonwoven fabric layer.

In general, the fibers of the nonwoven fabric may have a fineness of, for example, at least 0.5 dtex and (independently of this) of z. B. have at most 5 dtex. The fiber length may, for example, be at least 12.5 mm and (independently thereof) not more than 100 mm. The thickness of the nonwoven fabric layer may, for example, be at least 1 mm, preferably at least 1.5 mm; possible upper limits can z. B, at most 10 mm, 8 mm, 6 mm or 4 mm.

In a preferred embodiment, the fibers in the nonwoven layer are substantially isotropically oriented. This means that the ratio of in each case one of two mutually perpendicular surface directions, namely the machine direction and the transverse direction, should not exceed a limit. Namely, the fibers oriented in the machine direction are to be the transversely oriented fibers in a ratio of at most 1. 8: 1, preferably at most 1. 7: 1, more preferably at most 1. 6: 1. Particularly preferred would be a ratio of 1: 1, for technical reasons, a lower limit but, for example, at 1, 1: 1 or 1, 2: 1 are. In addition to the orientation in the machine and transverse directions, in the "isotropic" arrangement fibers should also be oriented perpendicular thereto, ie in the thickness direction. In a preferred embodiment, the pile may also be passed over a compression roll and compressed therefrom in the machine direction (the compression roll reduces the belt speed). This can advantageously increase the proportion of fibers oriented in the thickness direction. The above-mentioned ratio (Fasern- machine direction: the fibers _Qu rearing) can then also be less than 1: 1, preferably at most 0.9: 1, 0.8: 1, 0.7: be 1: 1; and 0.6 Possible lower limits are, for example, at least 0.3: 1 or 0.4: 1.

A correspondingly isotropic arrangement can be advantageous, for example, insofar as the nonwoven fabric layer with a certain minimum thickness can be easily achieved with the fibers oriented in the direction of thickness, which may be of interest with regard to the desired thermal insulation. The fibers with an air flow are preferred for producing the nonwoven fabric layer guided deposited on a support (pile formation), which can achieve such an isotropic arrangement.

In a preferred embodiment (generally also independent of the isotropy), the density of the fibers is constant over the entire fiber composite, which in this case refers to the mass density per volume, that is to the weight of the fibers per unit volume. It should therefore have the same mass density with respect to the surface directions between the air spaces and in the thickness direction of these then the fiber composite. This can be achieved, for example, by structuring already taking place at the processing stage of the pile or at the pile laying (see below in detail). In simple terms, therefore, for example, where the elevations of a topography are to be arranged, more fibers are deposited.

In the nonwoven fabric layer according to the invention, in the case of preferred embodiments, several layers can also be combined, ie the fiber composite can also have approximately a woven layer, a knitted layer, a net / mesh and / or a film. However, a fiber composite composed exclusively of a consolidated pile is preferred. The invention also relates to protective clothing with a nonwoven fabric layer according to the invention, such as protective jackets and / or pants, in particular for firefighters. In this case, the nonwoven fabric according to the invention may also be combined with one or more layers, for example a further nonwoven layer, a woven layer, a knitted layer, a net / mesh and / or a film. The nonwoven fabric layer can be provided as a so-called thermal liner in a multi-layer composite.

As already mentioned, the invention is also directed to a production method, wherein the statements made above should also be expressly disclosed in this regard. To prepare the nonwoven layer, a pile is provided, which is solidified to the nonwoven fabric layer. The solidification can generally be carried out chemically, thermally and / or mechanically, preferably at least mechanical fastening, if appropriate in combination with a preceding partial thermal hardening (see above). Preference is not chemically solidified, so only mechanically and optionally thermally, more preferably exclusively mechanically. In general, the mechanical consolidation can be a needle and / or hydroentanglement, the latter being preferred.

The term "pile" can also be read on a multi-ply pile which can be produced, for example, by laying a ply pile in. However, it can also be preferred that two different pile piles are brought together (stacked) to form a pile pile In a respective pile, the fibers are, for example, merely held together by fiber-fiber cohesion.

In general, it is also conceivable that for the production of the nonwoven fabric layer, a pile layer already previously at least partially solidified, ie a nonwoven fabric layer, is joined to another layer (eg a pile or a further nonwoven fabric layer), for example by hydroentanglement, However, a common bonding of the fibers to the nonwoven fabric would be preferred which all fibers are solidified as previously not proportionately solidified together.

In a preferred embodiment, the holes are introduced into the solidified nonwoven fabric, so it is first solidified and then the holes are introduced. The holes are preferably introduced by means of a water jet, for example on a so-called imaging drum. In general, a post-treatment can be carried out with a fluorocarbon finish, which can possibly also help to improve the THL.

The application of a topography for the definition of the air spaces (see above) can be done, for example, on the already consolidated nonwoven fabric. In this case, the topography is preferably first introduced into the solidified nonwoven fabric and then the holes are introduced. The introduction of the air spaces and holes preferably takes place in each case by means of a water jet, wherein different masks are used for the topography and the holes. For this purpose, for example, the same imaging drum sequentially equipped with the two masks and the web material are stored during the refilling. Preferably, however, a further imaging drum is provided, that is to say a reel-to-reel process management; the two or at least two masks can be provided on different roles of the same machine. The time sequence refers to a particular location of a web material, the web material in the whole can be edited at the same time accordingly.

In a preferred embodiment, the pile for predefining the air spaces and / or holes, preferably excluding the air spaces, with a varying with respect to its surface directions fiber density (based on the area) is taken. Thus, it varies according to the basis weight over the pile, namely, it is smaller in areas of lower fiber density and higher in areas of greater fiber density. Lesser density areas then define the air spaces / holes; in the consolidated nonwoven fabric layer, an air space / hole is accordingly arranged where a region of lesser density was in the pile. Before- In this way, the airspaces are predefined; For example, areas of increased fiber density then give the above-described elevations of a topography. In general, the fiber density in a range of "low" fiber density, for example, by at least, 80%, 60%, 40% and 20% less than in a range of increased fiber density (in a comparison of maximum values).

In general, the pile laying can be done mechanically and / or aerodynamically and / or electrostatically, wherein in the former case, the pile (or a layer thereof), for example, from a card / a carding machine is removed. In the aerodynamic pile laying the fibers are deposited by means of an air flow on a support. In general, this can also take place, for example, immediately after fiber formation (from a polymer melt at a nozzle), ie, the air flow can deposit the fibers formed at the nozzle on the carrier (eg, melt-blown nonwoven). Electrostatically, the polymers can, for example, in an electric field at high voltages divided into very fine fibers (nanofibers) and stored. In general, the pile may be formed of staple fibers and / or continuous filaments (both read the term "fiber"), preferably staple fibers.

In a preferred embodiment, the pile is guided with a flow of air deposited on a carrier, preferably starting with a so-called Airlaid carding of staple fibers. The varying fiber density (see above) is preferably achieved by a variation of the air flow, namely a variation with respect to the surface directions of the pile. For this purpose, for example, upstream or downstream of the air-permeable support, a mask can be introduced into the air flow, the through-openings of which then define areas with increased mass flow, whereas other areas are shadowed. In order, for example, to define discrete elevations, that is to say no strips, for example, such a mask is then moved along with the carrier when the pile is deposited. The mask can, for example, be guided by bands, for example. It is also possible to arrange a mask directly on the support, that is to cover its normally even air-permeable surface locally. Apart from such a cover, the carrier is otherwise permeable to air insofar as the fibers can accumulate on its surface, but this surface does not prevent a laminar flow.

The invention also relates to the use of a presently disclosed nonwoven layer for heat protection textiles, especially for protective clothing, in particular for protective clothing in the fire and / or military, preferably in the

Fire department, preferably for protective jackets and / or pants.

In the following, the invention will be explained in more detail with reference to embodiments, wherein the individual features in the context of the independent claims in another combination may be essential to the invention and continue to distinguish not in detail between the different categories of claims.

In detail shows

FIG. 1 shows a first nonwoven fabric layer according to the invention;

FIG. 2 shows a second nonwoven fabric layer according to the invention;

3a, b, a third and fourth nonwoven fabric layer according to the invention;

FIG. 4 shows the structuring on the flattening level for producing a nonwoven fabric with air spaces.

FIGS. 1 to 3 show nonwoven fabric layers 1 according to the invention, in each case one nonwoven fabric layer 1 in a schematic section, wherein the sectional plane lies parallel to the thickness direction 2. Two side surfaces 3a, b of the nonwoven fabric layer 1 are opposed to each other with respect to the thickness direction. In all cases, the fiber composite 4 of the nonwoven fabric layer 1 is composed of a fiber mixture. It contains 60% Preox fibers, 20% polyacrylate fibers and 20% PE / PET fibers. In the case of the embodiment according to FIG. 1, the nonwoven fabric layer 1 is structured with air spaces 5a, which are open towards the side surface 3a. Further, in the nonwoven fabric layer 1 holes 6 a are introduced, the lay as through holes 6 a through the entire nonwoven läge 1 between the opposite side surfaces 3 a, b extend.

The through-holes 6a have an opening cross-section of about 8 mm ² taken in the surface directions 7 and averaged over their respective extent in the thickness direction ² . In contrast, the average cross-sectional area of the air spaces 5a forming webs is about 200 mm ² . However, in contrast to the holes 6a, the air spaces 5a do not extend through the entire nonwoven layer 1, but only over approximately 60% of the thickness, namely 1.5 mm, with a thickness of the nonwoven layer of 2.5 mm.

In order to produce the nonwoven fabric layer 1 according to FIG. 1, a pile is deposited with a fiber density varying in relation to the surface (compare FIG. 4). There are areas of increased fiber density and areas of lower fiber density (relative to the area) in the pile, the latter predefine the air spaces 5a. After solidification of the pile, the fiber composite 4 is present, whose upper side surface 8a is shaped with a topography which delimits the air spaces 5a downwards and to the side. After solidification of the pile, the through-holes 6a are introduced by means of water jet.

For this purpose, the solidified pile is on a grid, so a mask on and acts from above the water jet. This penetrates the solidified pile and is deflected at the grid, so to speak, reflected into the pile inside. The deflected beam or the deflected beam then displace fibers, the holes are created. These are then arranged relative to the grid where it has elevations due to the grid structure (negative image). As an alternative to depositing a pile with varying fiber density, the nonwoven fabric layer 1 according to FIG. 1 can also be produced starting from a flat pile. The air spaces 5a and the through-holes 6a are then introduced after hydroentanglement of the pile, in each case by means of a water jet with different masks. Each of the masks is placed on an imaging drum that traverses the web material in a Ree / to Ree / process guide. The air spaces 5a with a first mask and then the through-holes 6a with a second mask are then introduced first at a respective location of the web material.

On the one hand, the air spaces 5a provide a good thermal insulation with regard to a load with the action of fire, ie extreme heat. The nonwoven fabric 1 is used as a thermal liner ^' n protective clothing for firefighters, so in protective jackets and pants. The passage openings 6a do not worsen the behavior under fire load (TPP value) or at least do not significantly impair it, but they do allow a heat dissipation from the inside to the outside. This helps to prevent overheating of the body.

The nonwoven fabric layer 1 according to FIG. 2 is likewise structured with air spaces 5a and holes 6b, the latter 6b not extending through the entire nonwoven fabric layer 1 in this case, but reaching into the nonwoven fabric layer 1 only slightly from the side surface 3b. The opening widths of the air spaces 5a and holes 6b correspond to those of the nonwoven fabric layer 1 according to FIG. 1. In order to produce the nonwoven fabric layer 1 according to FIG. 2, two pile layers, namely a pile layer in which the air spaces 5a are predefined, and a "flat", non-structured pile layer stacked together and solidified together, by means of hydroentanglement.

Subsequently, the holes are introduced by means of water jet from the lower side surface 3b in the figure. The pressure is adjusted in such a way that the water deflected at the grid only has an influence on the fiber composite up to a certain depth, after which the energy is sufficient for a rearrangement of the fiber. do not emanate any more, so the holes 6b do not pass through the entire nonwoven layer 1.

In the case of the nonwoven fabric layers 1 according to FIGS. 3 a and b, the air spaces 5 b are not open to a side surface 3 a of the nonwoven fabric layer 1, in contrast to the previously discussed embodiments, apart from the holes 6 c. In contrast to the air spaces 5a of the nonwoven fabric layers 1 according to FIGS. 1 and 2, the air spaces 5b are bordered on both sides by the fiber composite 4 in relation to the thickness direction 2. In their opening cross-section and their height, however, they correspond to the above-described embodiments.

With regard to the air spaces 5b and 6c, the nonwoven fabric layer 1 according to FIG. 3b corresponds to the embodiment according to FIG. 3a. In this case, however, holes 6c are additionally introduced from the side surface 3b. The nonwoven fabric 1 according to FIG. 3b corresponds to a combination of the nonwoven fabric layers 1 according to FIGS. 2 and 3 a. To produce the nonwoven fabric layer 1 according to FIG. 3a, a prestructured pile is folded together with a flat pile, the latter being laid on the topography; Subsequently, the two piles are solidified and are thereby introduced with a mask from above the holes 6c. In the case of the nonwoven fabric layer according to FIG. 3b, the holes 6b are then additionally introduced from below on an imaging drum with a further mask (see description of FIG. 2).

The air spaces 5 in the surface directions 7 limiting webs 9 of the fiber composite 4 in the case of Figures 1, 2, the topography; in the case of Fig. 3a, b, the webs 6 are within the nonwoven fabric layer. 1

FIG. 4 schematically illustrates the mass flow 40 in a carding machine 41. The fibers are separated in the fiber ejection unit 42 and supplied to the air flow which deposits the fibers on the carrier 43. The fibers are essentially isotropically oriented, is the ratio of the machine direction 44th oriented fibers to the oriented in the transverse direction 45 fibers so smaller 1, 6th In addition, fibers are also aligned in the thickness direction 2.

The carrier 43 is normally permeable to air over its entire surface, so that a laminar air flow sets and the fibers are deposited with a constant fiber density. In the present case, however, a masking 46 is provided on the carrier 43, ie the air and thus mass flow 40 is locally deflected. Where the masking 46, in the present case rectangles, are arranged, areas of lower fiber density are formed in the pile 47. After solidification of the pile 47 from the air spaces 5 and / or holes. 6

Claims

Expectations

Non-woven fabric would be included (1) for heat protection textiles

a fiber composite (4), which is at least partially made of inherently flame-retardant fibers,

wherein the nonwoven layer (1) has a plurality of air spaces (5) distributed in its surface directions (7) for thermal insulation, each of which is at least 0.1 in the thickness direction (2) perpendicular to the surface directions (7) of the nonwoven layer (1). mm, but only partially pass through the nonwoven layer (1) in the thickness direction (2),

and wherein in addition to the air spaces (5), a large number of holes (6) are made in the nonwoven layer (1), each of which extends from a side surface

(8) of the fiber composite (4) extend into it in the thickness direction (2) and thereby have a respective opening cross section of at least 1 mm ² and at most 15 mm ² in the surface directions (7).

Nonwoven fabric sheet (1) according to claim 1, wherein the holes (6) are through holes (6a) in the thickness direction

(2) each extend through the entire fiber composite (4) of the nonwoven layer (1).

Nonwoven fabric layer (1) according to claim 1 or 2, in which the air spaces (5a) also extend to one side apart from the holes (6).

(3) of the nonwoven layer (1) are open, i.e. a side surface (8) of the fiber composite (4) forming the nonwoven layer (1) is shaped with a topography and so webs

(9) of the fiber composite (4) are formed, which limit the air spaces (5) in the surface directions (7).

Nonwoven fabric layer (1) according to one of the preceding claims, in which the air spaces (5) in the surface directions (7) delimiting webs (9) of the fiber composite

(4) have a respective cross-sectional area of at least 20 mm ² and at most 3,000 mm ² .

5. Nonwoven fabric layer (1) according to one of the preceding claims, in which the air spaces (5) or the air spaces (5) in the surface directions (7) delimiting webs (9) of the fiber composite (4) are arranged regularly and have an average distance of have at least 3 mm and a maximum of 8 mm.

6. Nonwoven fabric layer (1) according to one of the preceding claims, in which the holes (6) are arranged regularly and have an average distance of at least 1 mm and at most 4 mm.

7. Nonwoven layer (1) according to one of the preceding claims, in which the inherently flame-retardant fibers in the nonwoven layer (1) are provided in a proportion of at least 40%.

8. Nonwoven layer (1) according to one of the preceding claims, in which the nonwoven layer (1) has a proportion of at least 10% non-inherently flame-retardant fibers.

9. Nonwoven layer (1) according to one of the preceding claims, in which the fibers in the nonwoven layer (1) are oriented essentially isotropically, the volume density of the fibers preferably being constant over the entire fiber composite (4).

10. Protective clothing with a nonwoven fabric layer (1) according to one of the preceding claims.

11. A method for producing a nonwoven layer (1) according to one of the preceding claims with the steps:

Providing a pile (47);

Solidifying the pile (47) to form the nonwoven layer (1), preferably mechanically, particularly preferably by means of hydroentanglement.

12. The method according to claim 11, in which the holes (6) are introduced into the solidified pile (47).

13. The method according to claim 11 or 12, in which the pile (47) is gripped with a fiber density that varies in relation to its surface directions (7) to predefine at least one of the air spaces (5) and holes (6).

14. The method according to claim 13, in which the pile (47) is placed on a support guided by an air flow, the varying fiber density of the pile (47) being achieved by means of an air flow that varies with respect to the surface directions of the pile.

15. Use of a nonwoven layer (1) according to one of claims 1 to 9 for heat protection textiles, in particular for protective clothing, in particular for protective clothing in the fire service and/or military sector.