EP2064381A2

EP2064381A2 - Light-weight spunbonded non-woven with particular mechanical properties

Info

Publication number: EP2064381A2
Application number: EP07818274A
Authority: EP
Inventors: Steffen Bornemann; Markus Haberer; Stefanie Streich; Dag Fohlin
Original assignee: Fiberweb Corovin GmbH
Current assignee: Fiberweb Corovin GmbH
Priority date: 2006-09-21
Filing date: 2007-09-20
Publication date: 2009-06-03
Also published as: US8138107B2; CN101517140A; DE102006044496A1; WO2008034613A2; MX2009002792A; WO2008034613A3; US20090233073A1; RU2435882C2; JP2010504441A; RU2009114845A

Abstract

Disclosed is a spunbonded nonwoven made of polyolefin filaments having a titer <1.6 dtex, the spunbonded non-woven having a surface weight = 20 g/m<SUP>2</SUP>, a density = 0.06 g/cm<SUP>3</SUP>, a maximum tensile force of between 9.5 and 62 N in the direction of the machine and of between 4.5 and 35 N perpendicular to the direction of the machine.

Description

Lightweight spunbonded fabric with special mechanical properties

The invention relates to a spunbonded nonwoven polyolefin filaments having a filament denier <1.6 dtex. The spunbonded fabric is characterized by special mechanical properties.

Moreover, the invention relates to the production of a laminate using the spunbonded nonwoven according to the invention and to the use of the spunbonded nonwoven and the use of the laminate produced with the spunbonded nonwoven.

Nonwovens are textile fabrics which can be produced in various ways. In addition to wet nonwoven fabric production and dry nonwoven fabric production, a distinction is made between melt spinning and meltblowing (meltblown technology). The two technologies of melt spinning and meltblowing have the advantage that the plastic granulate can be transferred directly into the finished fabric with the aid of a corresponding system. This explains the comparatively high productivity of these machines in the production of nonwovens.

In melt spinning polymer granules are melted in an extruder, pressed through the openings, so-called spinnerets, a spinning device and pneumatically or mechanically stretched after cooling. The process of drawing determines the final strength of the filaments. The loosely deposited filaments after being drawn on a moving filing belt become in contact with each other

Crossing points chemically or thermally to so-called binding points solidified. As the solidification increases, the softness of the nonwoven fabric thus formed decreases, and its flexural rigidity increases. Several identical or different superimposed spunbonded layers can be thermally solidified, for example by calendering, to form a composite material (laminate).

In meltblowing, the productivity is lower than in melt spinning. In addition, the nonwoven fabrics produced by melt blown have a lower mechanical strength than those produced by melt spinning. However, the nonwovens produced by melt blowing are characterized by very good barrier properties.

The aim of a low-cost nonwoven production is therefore the replacement, or in the case of the production of a laminate, the reduction of the nonwoven webs produced by meltblowing by such nonwovens, which were ideally made entirely by melt spinning.

The properties of a spunbond web are comprehensively described by the basis weight and density as well as the mechanical properties, e.g. the maximum tensile strength and the maximum elongation at break, continue through the

Barrier properties, e.g. the waterproofness and air permeability.

The basis weight of a spunbond indicates its mass as a function of the area in g / m ² , the density of a

Spun nonwoven the quotient of the basis weight and the Thickness of the spunbond corresponds. The reduction in the basis weight of a spunbonded fabric can therefore be achieved either by reducing the spunbonded density or by reducing the spunbonded thickness. In the normal case and with constant maintenance of all other production parameters, however, both are at the expense of the mechanical properties and also at the expense of the barrier properties of the spunbonded nonwoven.

Nevertheless, the reduction of the basis weight is a central parameter in the product improvement because it significantly influences the wearing comfort of the products made of the nonwoven fabric. For example, babies' diapers, incontinence products and feminine hygiene products are seeing a steady trend towards more lightweight spunbonded fabrics. In contrast, the air permeability decreases with increasing web thickness. At the same time, however, these products require the guarantee of mechanical properties and barrier properties, even at a reduced weight per unit area. The basis weight, mechanical properties and barrier properties of a spunbonded nonwoven, however, depend on various parameters. A crucial parameter, which determines all mentioned sizes, is the filament titer. The filament titer of a yarn or a filament is given as a length-related mass and describes its fineness. A high yarn count means a smaller mass / length ratio. The yarn count is measured in tex (tex), where 1 tex is 1 gram per 1000 m, or a decitex (dtex) corresponds to 1 gram per 10 000 m.

Lower spunbond thicknesses are generally accessible through the use of filaments with a lower filament titer, because finer filaments, with the same overall throughput and at the same time unchanged speed of the conveyor belt in the web for web formation, due to their smaller diameter, a nonwoven layer of lesser thickness, usually higher density result.

Using conventional melt spinning technologies (US 3,692,618, US 5032329, US 5814349, WO03038174 or WO02063087), finer filaments are produced by reducing polymer throughput (in grams of polymer per minute and hole). However, this approach is associated with a reduction in overall plant throughput and therefore undesirable in terms of productivity. By contrast, increasing the overall throughput, while keeping the other production parameters constant, generally leads to a thickening of the filaments and thus to an increase in the filament titer. An increase in filament titer, however, is undesirable in view of the objective of the present invention, which is to produce a lightweight spunbond web.

If, in accordance with DE 10360845 A1, a spinning device with a spinning plate having a spinning device with a significantly increased number of nozzle bores per meter of spinning plate is used to produce the filaments forming the lightweight spunbonded nonwovens, the polymer throughput is reduced in grams per unit time and per hole, however, the overall throughput remains unchanged overall. At the same time one obtains finer filaments, which allow the production of lightweight spunbonded nonwovens. A common problem of the prior art spunbond webs of lesser weight, as already mentioned, is the low mechanical stability. Especially transversely to the machine direction, such spunbonded fabric can be easily torn and have a low dimensional stability. In the case of WO99 / 32699, which discloses a spunbonded nonwoven having basis weight of about 13.6 g / m ² , this disadvantage is overcome with additional expense by increased bonding and a special pattern of the gravure roll during thermal bonding.

The prior art also discloses multilayer composite nonwovens (laminates) whose outer layers consist of melt-spun spunbonded nonwoven layers, while at least one of the inner layers consists of very fine fibers, which are preferably produced by meltblowing. The low mechanical

Resilience of the layers produced by meltblowing makes the outer spunbonded nonwoven layers produced by melt spinning absolutely necessary to give the composite nonwoven overall good mechanical strength. The production of spunbonded fabrics with the best possible combination of

Barrier properties and mechanical properties so far only guaranteed by the production of such laminates.

In addition, spunbonded nonwovens which can be produced solely by melt spinning are known from the prior art, with filaments having a low filament titer being used. Thus, US Pat. No. 5,885,909 discloses a nonwoven fabric composed of fibers having a filament titer of only 0.33 dtex and comprising a polyolefin, which is distinguished by improved barrier properties and respiration properties. The grammage is, at a nonwoven thickness of 0.33 mm and a density of 0.1336 g / cm ³ , but with ≥ 44.1 g / m ² comparatively high.

An alternative process for producing lightweight spunbond webs from olefin polymers is described in US 2004/0070101. The extruded filaments have an "island-in-the-sea" structure, with the sea polymer having dissolution properties other than the Icelandic polymer and being removed from the web after disbonding by disbonding.

Against this background, the object of the invention is the production of lightweight spunbonded nonwoven webs with improved mechanical properties. Here, the improvement of the mechanical properties should also have a positive effect on the barrier properties (barrier properties). In addition, the production of the spunbonded to ensure productivity without reducing the overall throughput.

Furthermore, the object of the invention is to provide one in comparison to others

Nonwoven laminates (laminates) of lightweight laminate with improved mechanical and improved barrier properties.

To solve the problem polyolefin filament are used with a filament denier <1.6 dtex, which result in the application of the melt spinning technology spunbonded, which is characterized by a basis weight <20 g / m ² , and a density of ≥ 0.06 g / cm ^3, and a Hochstzugkraft 10-62 N in machine direction and from 5 to 35 N in the cross machine direction.

The core idea of the invention is based first of all on the general knowledge that the mechanical properties of a nonwoven, especially from the filament titer, i. depending on the fineness of the filaments used. For between filaments of greater fineness (i.e., lower filament titer), a greater number of crossing points will form after filament deposition, provided the other parameters of nonwoven production are substantially unchanged. As a result, a larger number of binding sites will be present after chemical or thermal bonding of the web. With out of this

Reason is the mechanical properties of nonwovens, filaments with lower Filamenttiter, improved. However, the principle that finer filaments allow the formation of nonwovens with steadily improving mechanical properties is not considered unrestricted.

The inventors of the nonwoven fabric according to the invention have recognized that straight filaments with a filament titer of at most 1.6 dtex, in particular in the range from 1.6 dtex to 1.0 dtex, permit the production of nonwovens whose surface weights are only 4 to 20 g / m ² , in particular 4.0 to 12 g / m ² and whose mechanical properties at the same time represent an optimum. Although due to the increasing fleece density with increasing fineness of the filaments and the surface weight of a nonwoven fabric, nevertheless, there seems to be a window in terms of Filamenttiter in which the improve disproportionately mechanical properties or the barrier properties compared to the flat weight.

The spunbonded fabric according to the invention is lightweight and at the same time has improved mechanical properties. In addition, the barrier properties of the spunbonded fabric are improved despite the lightweight. "Lightweight" in the context of the invention means that the nonwoven fabric has a surface weight of 4 to 20 g / m ^2. The special feature is that the nonwoven fabrics according to the invention, despite the low

Flat weight by mechanical properties that outperform conventional nonwovens with comparable surface weights.

In the following, the preferred embodiments of the invention will be explained in more detail.

In one embodiment, the spunbonded web has a density in the range of 0.06 to 0.084 g / cm ³ . The upper limit of the density of 0.084 g / cm ³ applies to spunbonded nonwovens whose

Flat-weight of the corresponding under this ceiling provided for the flat weight of about 20 g / m ^2. The lower limit for the air permeability of these spunbonded nonwovens is 3100 l / (m ^{2 #} s) and the upper limit is 8400 l / (m ^{2 #} s). By contrast, the waterproofness is comparatively high; the water column can be up to 17 cm.

In a preferred embodiment, the spunbonded nonwoven has a surface weight of at most 12 g / m ² . For spunbonded nonwovens with a surface weight in the range of 4 to 12 g / m ² , which are characterized as particularly homogeneous and lightweight, is the Density maximum 0.073 g / cm ³ . Since the density and the air permeability behave inversely to each other, the lower limit of the air permeability is significantly higher for spunbonded nonwovens of this more lightweight embodiment with 3900 l / (m ^{2 »} s). Accordingly, the waterproofness is lower with a water column of no more than 11 cm.

The upper limits for the maximum tensile force are significantly lower for spunbonded nonwovens with surface weights in the range of 4 to 12 g / m ² than for spunbonded nonwovens with surface weights above 12 g / m ² . For spunbonded nonwovens with surface weights up to 20 g / m ² , the maximum tensile force can be up to 62 N in the machine direction (MD) and up to 35 N across the machine direction (CD). For spunbonded nonwovens with a basis weight of less than 12 g / m ^2, the maximum tensile force in the machine direction (MD) is a maximum of 32 N and a maximum of 20 N across the machine direction (CD).

The maximum tensile strength of a spunbonded fabric of up to 12 g / m ² is up to 75% in the machine direction and up to 75% across the machine direction.

In a particularly preferred embodiment, the spunbonded web has a density of 0.06 to 0.07 g / cm ³ and an air permeability of between 3900 and 8300 l / m ² s and a water column of between 7 and 11 cm. The measured air permeability, due to the lower density of the spunbonded fabric with 3900 l / m ² s, a lower limit, which is significantly higher than the corresponding lower limit of the air permeability for a spunbonded fabric having a density in the range of 0.06 to 0.084 g / cm ³ . The one for the water column measured values are for the particular preferred spunbonded with the lower density on the other hand with 7 to 11 cm in a narrower range than for the spunbonded with the density in the range of 0.06 to 0.084 g / cm ³ , for a water column of 5 to 17 cm was measured.

Particularly preferred is a filament titer in the range of 1 to 1.3 dtex. Filaments of this fineness allow the production of spunbond webs having a basis weight of less than 20 g / m ² .

To obtain such filaments and thus for the production of the nonwoven fabric according to the invention are especially suitable polyolefin polymers and copolymer blends of the same. "Polymers" are macromolecular substances made from simple

Molecules (monomers) by polymerization, polycondensation or polyaddition are constructed. The class of polyolefins includes i.a. Polyethylene (HDPE, LDPE, LLDPE, VLDPE, ULDPE, UHMW-PE), polypropylene (PP), poly (1-butene), polyisobutylene, poly (1-pentene), poly (4-methylpent-1-ene), polybutadiene .

Polyisoprene, as well as various olefin copolymers. Besides these, heterophasic blends are also among the polyolefins. Thus, for example, polyolefins, in particular polypropylene or polyethylene, graft or copolymers of polyolefins and α, ß-unsaturated carboxylic acids or carboxylic anhydrides can be used.

However, the particular suitability of the polyolefins does not exclude the use of polyester, polycarbonate, polysulfone, polyphenylene sulfide, polystyrene, polyamides or mixtures thereof. The charge of the starting polymers is not conclusive in both cases. All other melt-spinnable polymers known to the person skilled in the art are therefore not excluded from the use for producing the spunbonded fabric.

Polyethylene and polypropylene, as well as olefinic copolymers or mixtures thereof, are particularly suitable for the production of the nonwoven fabric according to the invention. It goes without saying that even the polyethylene used a

Mixture of different polyethylenes can be. The same applies to the polypropylene used.

Polypropylene produced with metallocene catalysts (m-PP) has a more homogeneous molecular weight distribution

On polymer units. This could explain that m-PP still results in filaments of small diameter even at greatly increased throughput rates.

It is envisaged that the polymer prior to extrusion

Fillers or pigments are added. In principle, all fillers or pigments known to those skilled in the art and suitable for the intended use of the nonwoven fabric are suitable. For cost reasons alone, calcium carbonate is a particularly interesting filler. Titanium dioxide (TiO ₂ ) is also suitable as a filler and is intended for the production of the nonwoven fabric according to the invention.

In a particularly preferred embodiment, the filaments can have a filler content of more than 5% by weight. The average particle size of the filler (D50) is preferably 2 microns to 6 microns, wherein the top cut (D98) of the particles is <10 microns.

The solidification of the spunbonded fabric can be carried out by all methods known to the person skilled in the art. Preferably, the solidification is chemical or thermal type. During thermal consolidation by calendering, the nonwoven thickness is reduced in the region of the embossing points.

The nonwoven thickness of the consolidated spunbonded fabric is in the range of 115 to 296 μm. In this case, the nonwoven thickness for those with a spinning device with 5000 holes / m (with a spinning beam width of 150 mm) in the range of about 130 to about 296 microns. The nonwoven thickness for those with a spinning device having 7000 holes / m (with a spinning beam width of 150 mm) is in the range of about 115 to about 266 microns. This shows that finer filaments tend to result in lower web thicknesses.

It is envisaged that the spunbonded nonwoven according to the invention forms a layer in a laminate consisting of at least two spunbonded nonwoven layers. Depending on the need for use, the second or further layers may have similar or distinct other properties than the spunbonded nonwoven according to the invention. Due to its lightweight nature, the nonwoven fabric according to the invention is suitable for a large number of combinations. It is also conceivable that one or more of the layers of the laminate is produced by melt blowing.

In the context of the invention are also the many uses of the spunbonded fabric. As the most important

Uses for the nonwovens according to the invention the production of lining fabrics, personal hygiene articles (diapers, sanitary napkins, cosmetic pads), cleaning wipes and mop cloths, and for gas and liquid filters, wound dressings, wound compresses are provided. Also the production of insulating materials, acoustic nonwovens and

Roof underlays is conceivable. The use as Geovlies is conceivable. Geovliese for example in the attachment of dykes, in the field of green roofs, as a layer of a landfill cover for the separation of soil layers and bulk materials or as an intermediate layer below the ballast bed of a

Road surface used. Also in agriculture and horticulture, the nonwovens are useful as a cover.

In the following, the invention will be explained in more detail by way of example with reference to FIGS. 1 to 7. However, the abovementioned examples are intended to explain the invention only in terms of its specific features and not restrict it.

Show it:

Fig. 1 shows the fiber denier (filament titer), measured on spunbonded nonwovens with different weight per unit area. Fig. 2 shows the spunbonded density for the various spunbonded nonwovens applied over the basis weight. Fig. 3 and Fig. 4 show the maximum tensile force for

Spun nonwovens with different surface weights, shown for machine (MD) and transverse (CD) directions. Fig. 5 shows the air permeability measured on spunbonded nonwovens with different basis weight. Fig. 6 shows the water column of the spunbonded nonwoven with different basis weight. Fig. 7 shows light micrographs of lightweight spunbond webs.

Explanation of the symbols in the illustrations:

Representation in the PP-type Düsenboh- filament fineness

Figures tion density and tables of the spinning plate (dtex)

(per meter)

ZN-PP titer 2.1 dtex

2.1 (5,000)

Ziegler - 5,000

ZN-PP titer 1.8 dtex

Natta 1.8 (5,000)

PP

ZN-PP titer 1.3 dtex

D 1.3 (7,000) m-PP titer 1.3 dtex

7,000 1.3 (7,000) metallocene m-PP titer 1.1 dtex PP

* 1.1 (7,000)

The total number of holes per meter of spinning plate is given, whereby the width of the spinning package surface provided with nozzle bores is 150 mm.

example 1

From a polypropylene produced by Ziegler-Natta catalysis (Moplen HP560R, manufactured by Basell), hereinafter referred to as ZN-PP, spunbonded nonwoven spunbonded nonwoven webs of various basis weight were prepared by melt spinning. The filament titer the filaments forming the spunbonded webs were set at 1.3 dtex, 1.8 dtex and 2.1 dtex.

The corresponding spunbonded nonwovens have been designated as "Sample 1" to "Sample 14". The composition, process conditions and characteristic properties of the spunbonded nonwovens produced from ZN-PP are shown in Table 1.

The spunbond webs were made on a conventional "Reicofil 3" spunbonded web in the form that: a., A conventional spinner having a spinning device with 5,000 orifices per meter of spinning plate, a 150 mm orifice of the spinneret surface area provided with nozzle bores ("Sample 1-10 ") as well as b. a modified spinning apparatus including a spin plate with increased number of nozzle holes per face of the spin plate of 7,000 nozzle holes per meter of spinplate, a width of the 150 mm nozzle-bore spin pack surface ("sample 11-14") was used.

Example 2

For comparison, with this modified spinning device with increased number of nozzle holes per meter spinning plate

(7,000 nozzle bores per meter, width of the spinneret surface provided with nozzle bores 150 mm) also different basis weight spunbonded nonwoven from a produced by metallocene catalysis polypropylene (Metocene HM562S, manufacturer: Basell), hereinafter referred to as m-PP produced. Of the Filament titer of the spunbond filaments was set at 1.3 dtex and 1.1 dtex.

The spunbonded webs thus produced are referred to as "Sample 15" through "Sample 24". The composition, process conditions and characteristic properties of spun nonwovens made from m-PP, as well as a laminate of two spunbond layers, are shown in Table 2.

The basis weights of the single-layer spunbonded webs produced were varied from 7 g / m ² to 20 g / m ² .

Another addition of melt additives or pigments, e.g. Titanium dioxide, did not occur here, although this is within the scope of the invention.

Example 3

The "Sample 25" spunbonded web was produced on a "Reicofil 3" spunbonded web in such a way that a laminate was formed in which two spunbonded layers were joined together in one process step. For this purpose, a configuration was selected in which a conventional spinning device (spinning disk with 5,000 nozzle holes per meter, width of the spin pack surface provided with nozzle bores 150 mm) and for producing the second spunbonded layer (b) for producing the first layer (a) with an increased spinning device with increased Number of nozzle holes per spinline surface area (7,000 nozzle holes per meter of spinplate, 150 mm spooled package width of nozzle bore) was used. The total plant throughput was chosen so that for both spinning devices (a) and (b) a same throughput was achieved. Due to the different configuration of the two spinning devices (a) and (b), this means that the flow rate through the nozzle holes at the spinning device (a) about 0.63 g _Po i _ymer / hole * min (Sample 25 Layer 1), and for spinner (b) was about 0.45 g _polymer / hole * min (sample 25, 2nd layer).

The process was conducted in such a way that in spinning device (a)

ZN-PP (Moplen HP560R), and in spinner (b) an m-PP (Metocene HM562R) was processed. Since the throughput of the two spinning devices was chosen approximately equal, the basis weight of both layers of the laminate is the same, ie, a laminate was prepared in which the weight per unit area of the individual layers is 5 g / m ² .

The following is the explanation of the data shown in the figures.

FIG. 1 shows that spunbonded nonwovens with different basis weights have a very homogeneous filament denier (filament titer).

FIG. 2 shows that the spunbond density, calculated from the measured sizes basis weight and spunbonded thickness, can be significantly changed by the set process conditions. The calculated spunbond density is shown as a function of the basis weight of the spunbonded web. The filaments produced with a 7000-hole / m spinner have a filament titer of 1 to 1.3 dtex. Especially when using this spinning device with increased number of holes (7,000 nozzle holes per meter at a width of the nozzle bore provided spinning package area of 150 mm), it can be seen from FIG. 2 that the spunbonded density is significantly higher than when using the conventional spinning devices (spinning plate with 5,000 nozzle bores per meter with a width of the spinneret surface of 150 mm provided with nozzle bores). The increase in nonwoven density using a higher hole density spinner is due to the higher fineness of the fibers.

In FIGS. 3 and 4, for the mechanical properties of the spunbonded nonwoven, the maximum tensile force, measured on spunbonded nonwovens of different weight per unit area, in the machine direction (MD), see FIG. 3 and transverse to the machine direction (CD), see FIG.

It can be seen that the maximum tensile force, in both the machine and transverse directions, is within a narrow range, regardless of the spinning apparatus used in the manufacture. The somewhat lower maximum tensile strength values for spunbond nonwovens produced from m-PP compared to ZN-PP could be due to molecular differences in the two polymers. The melt flow index of the ZN-PP used is given as 25 dg / min, that of the m-PP used at 30 dg / min, which indicates a lower molecular weight for the m-PP.

Gem. Fig. 5 follows from the presented in connection with Fig. 2 change in spunbonded density a significant change in the air permeability of the spunbonded nonwoven. The air permeability data shown in Figure 5 can be used to illustrate the effects of the two spinning devices used on the spunbonded webs made therewith. So In absolute terms, significantly lower air permeabilities were measured for the lightweight spunbonded webs produced using spinnerets with increased number of nozzle bores per face of the spinning plate (7,000 nozzle holes per meter; 150 mm spinneret bore width provided with nozzle bores), than for those spunbonded nonwovens; which using a spinning device with 5,000 nozzle holes per meter; Width of the spin hole plate surface provided with nozzle bores 150 mm) were prepared.

However, it is striking that spunbonded nonwovens having a weight per unit area of 12 g / m ² (sample 21: spunbonded density 0.071 g / cm ³ , m-PP filament denier 1.1 dtex, spinning plate with 7,000 nozzle bores per meter), 17 g / m ² (sample 6: Density 0.068 g / cm ³ , ZN-PP

Filament denier 1.8 dtex, spinning plate with 5,000 nozzle holes per meter) and 20 g / m ² (sample 1: density 0.068, ZN-PP filament titer 2.1 dtex, spinning plate with 5,000 nozzle holes per meter) quite a lying in a similar order of air permeability of about 5,320 l / m ² s.

Furthermore, a spunbonded web having a basis weight of 7 g / m ² and a density of 0.063 g / cm ³ (sample 24), which consists of m-PP (filament denier 1.1 dtex) with a modified spinning apparatus with an increased number of nozzle holes per area The spinning plate (7,000 nozzle holes per meter) was prepared, with 8,350 l / m ² s about the same air permeability on a spunbonded fabric with a basis weight of 10 g / m ² and a density of 0.058 g / cm ³ (sample 8), which made of ZN-PP (filament titer 1.8 dtex) with the spinning plate with 5,000 nozzle holes per meter was, or even a spunbonded fabric with a basis weight of 12 g / m ² and a density of 0.056 g / cm ³ (sample 3), which consists of ZN-PP (filament titer 2.1 dtex) with the conventional spinning device with 5,000 Dϋsenbohrungen per Meter was made.

As a result, this means that a nonwoven fabric made of finer filaments may have a lower air permeability due to the higher density, but at the same time can be significantly lighter. In addition, upon closer inspection of the curve, it is noticeable that the decrease in air permeability is not linear with increasing basis weight, i. As the basis weight increases, the air permeability differences between conventional and lightweight nonwovens become smaller.

In Fig. 6, the water column, each shown as a function of the basis weight of the spunbonded fabric.

FIG. 7 shows two light microscope images of two spunbonded nonwovens having a weight per unit area of approximately 7 g / m ² . Sample 10 (see Table 1) has a basis weight of 7 g / m ² . The filaments produced using a spinner having 5000 holes per meter of ZN-PP spinning plate have a titer of 1.8 dtex. The sample is shown at 10x magnification. Sample 24 (see Table 2) has a basis weight of 7 g / m ² . The filaments produced using a spinning device with 7000 holes per meter m-PP spinning plate have a titer of only 1.1 dtex. The sample is shown at 10x magnification. The photograph confirms the spunbond density measurements, sample 24 has the higher density. In the inventive, lightweight spunbonded nonwovens was under the condition that

a) the spunbonded filaments are spun using the modified spinning device with increased number of Dusenbohrungen per area of the spinning plate, b) the filament of the spunbond filaments is as low as possible, and c) the spunbonded web have an increased spunbond density, d) preferred m-PP is used for the production of spunbonded nonwovens,

observed the best possible combination of mechanical properties and barrier properties.

methods

The following methods were used to determine the properties of the spunbonded fabric according to the invention:

Filament titer / basis weight / fleece thickness / spunbonded density The filament titer was determined by means of a

Microscope. The conversion of the measured filament titre (in micrometers) into Dezitex was carried out according to the following formula (density PP = 0.91 g / cm ³ ):

dl _lL g 10 ⁴ w The basis weight determination (basis weight) of the spun nonwovens was carried out according to DIN EN 29073-1 on 10 x 10 cm specimens.

The thickness of the spunbonded web was measured as the distance between two plane-parallel measuring surfaces, between which the spunbonded webs are below a predetermined measuring pressure. The method was carried out analogously to DIN EN ISO 9073-2, whereby a coating weight of 125 g, a measuring area of 25 cm ² and a measuring pressure of 5 g / cm ² were used.

The spunbond density is calculated from the basis weight and the thickness of the spunbonded nonwoven.

Air permeability The air permeability of the spun nonwovens was measured according to DIN EN ISO 9237. The area of the measuring head was 20 cm ² , the applied test pressure 200 Pa.

Water column The determination of the water column was carried out in accordance with DIN EN 20811. Gradient of the test pressure 10 mbar / min. As a measure of the watertightness of the water pressure in mbar or cm water column is specified, in which the water exits first at the third point of the sample.

Mechanical properties

The mechanical properties of the spunbonded nonwovens were determined according to DIN EN 29073-3. Clamping length: 100 mm, sample width 50 mm, feed rate 200 mm / min. "Maximum tensile force" is the maximum force reached when passing through the force-strain curve, "Maximum tensile strain" is the strain in the force-strain curve associated with the maximum tensile force.

Claims

claims

1. spunbonded nonwoven polyolefin filaments having a filament titer <1.6 dtex, wherein the spunbonded nonwoven - a basis weight <20 g / m ² , and a density of ≥ 0.06 g / cm ³ , and a maximum tensile force of 9.5 to 62 N in the machine direction, and from 4.5 to 35 N across the machine direction.

2. Spunbonded fabric according to claim 1, characterized in that the spunbonded fabric has a density in the range of 0.06 to 0.084 g / cm ³ .

3. spunbonded nonwoven according to claim 2, characterized in that the spunbonded nonwoven at densities of 0.06 to 0.084 g / cm ³

Air permeabilities from 3100 to 8400 l / m ² s, and - has a water column of 5 to 17 cm.

4. spunbonded nonwoven according to claim 1, characterized in that the spunbonded - has a basis weight of 4 to 12 g / m ² , and a density in the range of 0.06 to 0.073 g / cm ³ .

5. spunbonded fabric according to claim 4, characterized in that the spunbonded fabric Air permeabilities between 3900 and 8350 l / (m ² "s), and has a water column between 7 and 11 cm.

6. spunbonded fabric according to any one of claims 4 and 5, characterized in that the spunbonded at densities of 0.06 to 0.073 g / cm ³ , a maximum tensile force - from 10 to 32 N in the machine direction, and between 5 and 20 N transverse to the machine direction.

7. spunbonded fabric according to one of claims 4 to 6, characterized in that the spunbonded fabric has a Hochstzugkraftdehnung of 20 to 75% in the machine direction, and from 20 to 75% transverse to the machine direction.

8. Spunbonded nonwoven according to one of the preceding claims, characterized in that the filaments have a filament titer in the range of 1 to 1.3 dtex.

9. Spunbonded nonwoven according to one of the preceding claims, characterized in that the consolidated spunbonded nonwoven fabric has a basis weight of about 7 to about 20 g / m ² .

10. Spunbonded nonwoven according to one of the preceding claims, characterized in that the nonwoven thickness is about 115 to about 296 microns.

11. spunbonded fabric according to any one of the preceding claims, characterized in that the polyolefin filament consist of polypropylene or polyethylene or a mixture of the two.

12. spunbonded fabric according to claim 11, characterized in that the polyolefin filaments consist of an olefin copolymer.

13. Spunbonded nonwoven according to one of the preceding claims, characterized in that the polyolefin filaments consist of a polyolefin produced by metallocene catalysis.

14. Spunbonded nonwoven according to one of the preceding claims, characterized in that the polyolefin filaments consist of a polypropylene prepared by metallocene catalysis (m-polypropylene).

15. Spunbonded nonwoven according to one of the preceding claims, characterized in that the polyolefin filaments contain a filler or a pigment.

16. spunbonded nonwoven according to claim 15, characterized in that the filler is calcium carbonate and the filler content, based on the polymer filament, a filler content> 5% by weight.

17. spunbonded fabric according to claim 15, characterized in that the top-cut of

Filler particle (D98) <10 microns and the average particle size of the filler (D50) is preferably about 2 to about 6 microns.

18. Spunbonded nonwoven according to one of the preceding claims, characterized in that the filaments produced in the melt spinning process and deposited to the nonwoven are solidified in a thermal and / or chemical manner.

19. Laminate composed of at least two spunbonded layers, wherein at least one layer consists of a lightweight spunbonded nonwoven according to one of claims 1 to 18.

20. Use of a spunbonded nonwoven according to one of claims 1 to 18 or a laminate according to claim 19 for the preparation of

Personal hygiene articles (diapers, sanitary napkins, cosmetic pads),

Cleaning cloths, wipes, mop cloths

Filtering e.g. for gases, aerosols and liquids,

Wound dressings, wound compresses,

Insulating materials, acoustic nonwovens, interlinings,

Roof linings,

Geovliesen, or covers for the field and vegetable economy.