FI116226B - Non-woven fabric composite, its use and method for its manufacture - Google Patents

Description

116226

NONWOVENS COMPOSITE, ITS USE AND METHOD FOR MANUFACTURING IT

FIELD OF THE INVENTION This invention relates to nonwoven composites, to their use and to a process for making nonwoven composites. In particular, a novel entangled nonwoven composite material comprising at least three layers is disclosed. The nonwoven material according to the invention can be used as a substrate for wiping products 10, especially for use as a substrate for wet wipes, which requires good liquid absorption and release properties.

BACKGROUND OF THE INVENTION In water-weaving a fibrous web, the fibrous web is bound by fine, high-speed water jets in the same way as knitting in the needling process. These high pressure water jets cause the fibers to rearrange in all three directions of the structure, resulting in significant bonding without the use of added binders or additional (e.g., thermal) bonding. In one of the widely used methods, the carded web is placed on a moving belt conveyor which conveys the web beneath several rows of water jets. The water pressure of the showers is gradually increased from the first • I · shower group to the last group. More information on hydroentangling can be found e.g.

U.S. Patent Nos. 3,485,706 and 3,445,708 to Evans, which are incorporated herein by reference.

• «· 25

Different types of nonwoven compositions can be used to make water-woven nonwovens. Typical fibers used are cellulose-based fibers such as cotton, pulp (pulp) or viscose, as well as synthetic fibers such as polyester: '' (typically polyethylene terephthalate). The widely used fiber blend is 30-70% viscose fibers 30 and 70% -30% polyester fibers based on the weight of the web.

Water-needled nonwovens have been used as substrates for pre-moistened towels, i. so • · called wet wipes. During the wiping operation, the liquid in the pre-moistened towel should be released on the wiping surface, e.g.

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2 116226 for polishing. In some applications, the released fluid should provide some special function to the surface, such as wetting the skin or disinfecting the surface. The substrate used for wet wipes, such as a nonwoven nonwoven, should have both desirable fluid absorption and retention properties as well as sufficient fluid release properties.

While nonwoven substrates comprising viscose and polyester fibers provide good liquid absorption and retention properties, these substrates typically release less than 50% of the wetting fluid during the wiping operation. This means that only a small amount of the added liquid will contribute to the intended function, such as cleaning, polishing or disinfecting. Thus, there is a need to develop the fluid release properties of nonwoven materials, particularly used in the manufacture of wet wipes.

It has been found that the more hydrophobic fibers, such as polypropylene (PP) fibers, are present in the nonwoven material, the better the fluid release properties.

Hydrophobic fibers are characterized by having a water contact angle greater than 90 °. Due to the hydrophobic fibers, the capillary pressure of aqueous liquids is low or even negative in the nonwoven material. As a result, aqueous liquids can be easily released from the nonwoven during the wiping operation and the amount of residual liquid in the wiping product after wiping is minimized.

The water absorption properties of the non-woven PP-containing nonwoven are significantly • · ·; * lower than those of non-woven fabrics containing more hydrophilic fibers. By increasing the amount of hydrophobic polypropylene fibers in the nonwoven, the spontaneous absorption of aqueous *: * ' note, for example, the increased liquid: ,,, · 'running on the surface of the nonwovens when the material is watered.

: The use of hydrophobic polypropylene fibers in nonwovens, which are used as substrates for wiping products, is limited because the liquid absorption properties • · 30 decrease as the amount of polypropylene fibers increases. Due to its chemical nature: Polypropylene has a low energy surface with a water contact angle of about 105 °. Due to the hydrophobic *; ** nature of the nonwoven material containing PP fibers, non-optimum cleaning properties are achieved when the nonwoven is used as a wiping product. The nonwoven liquid has an absorption capacity of 116226 3 and a low absorption rate, which also results in a relatively poor drying ability of the nonwoven during the wiping operation.

Composite and layered nonwovens are known in the art. A layered composite structure refers to a nonwoven fabric having at least two layers comprising at least partially different fibers or nonwoven compositions. Typically, the various layers of nonwovens are first made separately and then joined, for example, by calendering. Thus, patent application WO 98/03713 discloses a multilayer nonwoven backing sheet for use as a wet towel substrate, whereby the different layers 10 may contain different types of fibers.

Composite nonwovens can also be manufactured online, i. forming different layers (e.g., carded webs) and placing them on top of each other, whereupon the layers are bonded together. Various binding methods are used for this purpose. EP 0 531 096 discloses the use of a large number (ten) of carding machines which are fed with different fiber compositions or different fibers and the webs are typically wound with water.

SUMMARY OF THE INVENTION The present invention relates to a nonwovens composite formed by '·· * · * nonwoven layers bonded together by weaving fibers of different layers, wherein' · · 'the nonwoven layers comprise first and second outer layers, each of * * · ·; Comprising a mixture of hydrophobic and hydrophilic absorbent fibers as well as · · · *; a third intermediate layer of hydrophobic fibers sandwiched between the first and second outer layers of the "* I l" • · ... 25 with a weight ratio of hydrophobic to hydrophilic fibers in the first and second layers of from 20:80 to 80:20 and own. . pore volume distribution with at least 70% of the total pore volume associated with • · · • · · ·. · · *, For pores with an effective radius greater than 125 μιη.

The non-woven fabric composite of the invention is for use

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! ' as a substrate for wiping products such as wet wipes. With the said »| | The nonwovens composite material has improved liquid absorption properties, as well as improved liquid release properties.

116226 4

Another object of the invention is a method of making a composite nonwoven fabric comprising the steps of: forming a layered web comprising first and second outer layers, each comprising a mixture of hydrophobic and hydrophilic fibers and an intermediate layer of hydrophobic fibers between the first and second outer layers. , wherein the ratio of hydrophobic to hydrophilic fibers in the layers is 20:80 to 80:20, - hydroentangling of the layered web to bind the layers by fiber coiling, - drying the hydroentangled web.

Brief Description of the Drawings

In the drawing, Figure 1 shows a hydroentangling production line with three carding stations,

Figure 2 shows the cumulative volume of filled pores as measured by a porosimeter, Figure 3 shows the fluid absorption curves of the samples,

Figure 4 shows the cumulative fluid release of wet samples as measured by a wiping device, Figure 5 shows the wiping efficiency of dry samples as measured by a wiping device and; 1. Figure 6 shows the pore volume distribution.

* · · * 1 1 • · * »1 '! ". DETAILED DESCRIPTION OF THE INVENTION The structure of the composite nonwoven fabric according to the invention thus comprises a first and a second outer layer, as well as a third layer having one of its outer surfaces facing the outer surface of the first layer and the second layer. 1 · ·. forming a layer structure wherein the third layer is sandwiched between the first and second layers. The present invention provides non-woven fabric composite material which surprisingly has good water-based liquid release properties. The material also has good absorption properties and bulk. Typical hydrophobic fibers ·; ·; for use in nonwovens, the outer layers and / or the interlayer, are e.g.

Polyolefin fibers such as polypropylene and / or polyethylene fibers. Preferably, polypropylene fibers are used. Polypropylene fibers have many advantages such as low density such as 116226 5 as well as low shear and elastic modulus. In water-needled nonwovens, these properties of polypropylene fibers lead to soft and bulky nonwoven materials. Suitable hydrophobic fibers for the manufacture of water-needled nonwovens are fibers having a fiber titer of 1.3 to 3.8 dtex. According to a preferred embodiment of the invention, the hydrophobic fibers in the first and second outer layers are the same hydrophobic fiber as in the interlayer. It should be noted that fibers made from a hydrophilic synthetic or natural polymer can also be used as hydrophobic fibers if a suitable surface treatment produces a water contact angle greater than 90 °. These surface treatments can be, for example, chemical treatments from surface treatment with wax, fluorocarbon or silicone. Hydrophobic fibers may also be multi-component fibers having a hydrophilic or hydrophobic core polymer and a hydrophobic surface.

According to one embodiment of the invention, the hydrophilic absorbent fibers are selected from the group consisting of cellulose-based fibers, such as viscose, cotton or pulp (pulp) fibers. Viscose or lyocell are preferably used as hydrophilic fibers. Hydrophilic fibers are defined herein as fibers having an average water contact angle of less than 90 °.

According to a further preferred embodiment of the invention, the weight ratio of hydrophobic to hydrophilic * * 'fibers in the first and second outer layers is 30:70 - * * * * 70:30. According to a further preferred embodiment of the invention, the first and second outer layers are the same, i. they are made of the same fiber mixture. According to a further preferred embodiment, the first and second outer layers consist of ... 25 polyolefin such as polypropylene and viscose fibers and the intermediate layer polyolefin such as polypropylene fibers. According to a further embodiment, the first and:, ·. the second layer consists of polypropylene and viscose fibers in a weight ratio of about 50:50, »· · ·. ···. the interlayer being composed of polypropylene fibers. According to a further preferred embodiment of the invention, the composite nonwoven material consists of three layers, i. the first and second outer layers as well as the third layer having one of its outer faces facing the outer surface of the first outer layer and the other facing the outer surface of the second outer layer to form a layer structure.

6, 116226

In a typical composite nonwoven fabric according to the invention, the weight of each layer may be 10-80 g / m 2. The weight of the interlayer can often be greater than the weight of each of the outer 5 layers.

The nonwoven composite material according to the invention is made by a weaving process which generally comprises forming a layered nonwoven web, water weaving the web, drying the web and winding the woven nonwoven material. According to the invention, a 10-layered web may be formed by providing a first and a second web, both comprising a mixture of hydrophobic and hydrophilic fibers, as well as a third web comprising hydrophobic fibers directed against each of the first and second webs. floor.

15

Figure 1 schematically illustrates a hydroentanglement production line for the production of a three-ply web in which the parts are as follows: (11A, 11B, 11C) are fiber feeders for respective webs A, B and C. The fibers may be staple fibers curled and cut from polymer filaments. The reference numbers (12A, 12B, 12C) indicate the carding stations of the same webs and (13) the first hydroentangling station, (14) the second. 'A water needle station, (15) a dryer and (16) a nonwoven roller. Each of the Takes A, B and C

• · * * is brought together, with web B being sandwiched between webs A and C, before the first • · *: water jetting station, where the layers are bonded by winding, resulting in a bonded product with some single layers the fibers may extend into an adjacent layer 25 to adhere the layers together. This results in a composite structure having a · · '' * hydrophobic intermediate zone whose hydrophilicity increases toward the outer parts of the composite structure. . zones and surfaces that provide the product with the advantageous properties.

• I · · • | · ;;; 30 Non-woven material absorbs and retains liquid mainly of non-woven fibers; * formed between capillaries. The ability of a porous material, such as a nonwovens, to absorb and retain liquid can be characterized by the capillary pressure of the liquid in the material '! the pores. Capillary pressure is defined according to the Laplace equation, which is well known in the art: 7 116226 P = (2 γ cos Θ) / r where P is the capillary pressure, γ is the surface tension of the wetting liquid, Θ is the contact angle between the liquid and the capillary wall and r is the radius of the capillary. The rate of fluid absorption 5 is proportional to capillary pressure, and increases with increasing capillary pressure. This connection is shown in the Washbum equation

dV / dt = (r2 A) dP / 8r | L

Where A is the cross-sectional area and L is the capillary length, η is the viscosity of the liquid.

Unexpectedly, according to the invention, it has been found that not only the amount of hydrophobic fibers in the nonwoven fabric, but also the structure of the nonwoven fabric affect the release properties. This has been confirmed by tests comparing two nonwovens which contain the same amount of polypropylene but have a different structure. The structure of the invention was a layered structure as defined, while the reference product had a flat, non-layered structure but with the same polypropylene content. Thus, it was found that the composite structure had significantly better absorption and release properties.

20 During the wipe operation with a wet towel, liquid should be released from the • • * * · '·' surface as completely as possible. In this case, the pressure that ··! needed to release fluid from a wet towel is directly proportional to the capillary pressure of the fluid * · • · ♦ '· nest in the capillaries of the towel. Thus, it is desirable to produce a nonwoven substrate having a relatively low capillary pressure relative to the wetting fluid.

Capillary pressure can also be lowered by increasing the average pore size of the nonwoven material 'I'. One method of increasing the average pore size * · *: 30 is to increase the diameter of the fibers used to make the nonwovens material (denier). The pore size distribution also depends on the process technology and process settings, such as the hydroentangling energy used to make the nonwovens.

»» 116226 8

Nonwovens can be characterized by their pore volume distribution. In the composite structure of the invention, at least 70% of the total pore volume is associated with pores with an effective radius greater than 125 µm, or equally, with a capillary pressure of less than 530 Pa during fluid absorption. They can be further characterized in that at least 30% of the total pore volume is associated with pores with an effective radius greater than or equal to 150 μπι and a capillary pressure of less than 440 Pa during liquid absorption. The effective radius of the pores is preferably up to 800 μπι. However, it should be noted that these values of pore radius and capillary pressure refer to values measured during fluid absorption (progressive 10 cycles). Due to the hysteresis of the contact angle between fluid absorption and desorption, smaller pore volumes or higher capillary pressures would be obtained when the pore volume distribution is measured from the fluid desorption (retracting cycle). It should also be noted that the pore volume distribution of the composite structure represents the average value of all layers. The pore volume distributions are shown in Figure 6.

15 EXAMPLES Specimen Description

Both the sample of the invention and the reference sample were prepared using comparable process settings.

•> · »· •, '· · Composite structure ,,!; * The outer webs of the composite structure consist of a blend of 50% polypropylene and 50% viscose and have a basis weight of 15 g / m2. In the middle of the structure, there is a layer of 100% polypropylene (20 g / m2) between the outer layers of '· * 25. Thus, the total structure has a polypropylene content of 70% and a total basis weight of 50 g / m2. The composite structure was fabricated in the apparatus of Figure 1 by feeding suitable fiber blends to various fiber feeding stations. In hydroentanglement, the various webs are wound together with water jets, during which the layers are mixed to some extent, basically forming an intermediate zone having a high degree of hydrophobicity, which zone gradually becomes more hydrophilic as the transition to the outer zones of the hydroentangled web. The layers are bound together: '': and cannot be separated.

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Reference sample ^^ 6226

The reference sample consists of a substantially uniform mixture of 70% polypropylene and 30% viscose. The basis weight is also 50 g / m2. The reference sample is made with three combs, but the same fiber composition is fed to each comb.

5

test methods

Liquid Absorption Release Properties 10 Liquid Pore Symmetry Technology

The liquid absorption and release properties were supported by the liquid porosimeter technique (TRI Autoporosimeter) developed at the Textile Research Institute (TRI) in Princeton, New Jersey, USA. Mille and Tyomkin have described the technique in more detail in Journal of Colloid and Interface Science, vol. 162 (1994), p. 163-170. The autoporimetry chamber 15 was equipped with a nitrocellulose membrane with a nominal pore diameter of 1.2 µm (Millipore RAWP type, Millipore Corporation, Bedford, Massachusetts, USA). The liquid used was 0.1% aqueous Triton X-100 (surface tension 33 mN / m). A representative sample of 5.5 x 5.5 cm 2 was cut from non-woven fabric samples and covered with plexiglas having the same dimensions. Measurements were made in a pore beam range of 20 to 800 µm, corresponding to a pressure range of 13200 to 83 Pa. The measurement may comprise both progressive: (liquid absorption) and retractable (liquid desorption) measurement cycles. For analysis, measurement without sample was subtracted from the original data.

•: • •:: · ·:: Dynamic date erase test • · ': * ’: 25 Dynamic tests were performed on a wiping device. Two types of test were used to test the wet and dry wiping properties. i *. · Wiping test (wet sample) * ... 'A sample (7 cm x 10 cm) consisting of 4 g of test fluid / g of nonwoven was fixed at 2.4 kg *; · 30 on the bottom of the carriage (equivalent to 4.8 kPa load). The liquid used was 0.1% Triton:: X-100 in aqueous solution (surface tension 33 mN / m). The sled was pulled at a speed of 50 cm / s for 1 m against the wax fabric (there was a 3 mm pad under the wax fabric) and during the draw; 7 consecutive draws (= 1 measurement) were made on the same sample.

10 1 1 6226

Wiping test (dry sample) A 10.3 cm x 16.8 cm sample was mounted on the underside of a 1.3 kg (1.0 kPa) carriage. The liquid, in this case water, was uniformly applied to the steel support with 5 pipettes. Two different volumes of liquid were used for each sample: 10 ml and then a volume of 75% of the absorbance capacity of the sample. The carriage was pulled at a speed of 20 cm / s against the substrate and the amount of liquid absorbed into the sample during the measurement was measured with a balance.

Basic Test 10

Nebömassa

The non-woven bulk material was determined according to Edna Recommended Test Method ERT 40.3-90. Reported values are the average of 10 individual measurements.

15 Thickness

Nonwovens thickness was determined according to Edna Recommended Test Method ERT 30.5-99. Reported values are the average of 10 individual measurements.

Tensile strength and elongation 20 The tensile strength and elongation of nonwovens were determined by the Edna Recommended Test. Method ERT 20.2-89 except that the stretching speed was 300 mm / min. Reported • · ·. ·. : values are the average of 5 individual measurements.

This test method, based on the standard SFS-ISO 1833 (1991), is available for binary blends of polypropylene fibers with viscose, polyester, wool, cotton, etc.

* * »

The required amount of nonwoven was taken and the dimensions of the sample were measured. The mass of the sample was determined using an analytical balance. The viscose was dissolved in the non-woven fabric at 60%

Tim

with sulfuric acid at 60 ° C. The sample was mixed with a glass rod and the dissolution time was 6 to 11 minutes. After dissolution, the sample was rinsed thoroughly with deionized water and • »*» *. dried for one to two hours at 105 in a ventilated oven.

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n 116226 The sample was cooled to room temperature for about one hour and the mass of insoluble component (PP) was expressed as a percentage and in gmm of the total fiber mass of the mixture. The proportion of soluble component (e.g. viscose) was calculated from the mass loss. 5 The number of parallel measurements was four.

The results of the basic tests of the samples are shown in Tables I and II.

Table I.

Square weight Thickness Components (g / m2) (mm) Polypropylene Viscose

Composite structure Ävg 492 Ö / 72 6L2 322

Std 22 Ö22 LÖ LÖ

Min 4577 Ö28 6M 3L8

Max 52 ^ 0 0/75 682 332 N 20 „2Ö 4 4

Reference sample Ävg 542 Ö24 692 3Ö2

Std 12 0.03 Ö2 M

Min '51/7 028 69.3 29.8

Max 562 "029 7Ö2 30/7 N 30 3Ö 4 ~ 4 h • ·; 10 Table II.

• · »i t Draw dry (N) Draw wet (N) Draw dry (%) Draw wet (%)

'!' *, Composite- MD CD MD CD MD CD MD CD

* 1 »* · · * I structure": Ävg 682 242 482 Ä6J "572 Ϊ392 ΤΪ2 Π22

Std 12 WORK "82 1Ä 22 1Ö2 23 1Ö2

Min 642 ~ Ϊ92 372 "Ϊ42" 512 Ϊ212 "4Ϊ2 992

Max 752 282 ~ 632 19J Ί5Ι2 1542 ″ 632 132.3 ;; n 10 Tö Work H) lö I 1 t ____ _ _ 'Reference sample · ;;; Ävg "852 Ϊ82" 662 TÖ2 182 Ϊ582 57/7 Ϊ392

Std "52 Xi" 72 22 "52 Π2 42 M

Nfin 792 Ϊ32 ”522 ~ T £ 462 Ϊ402 4M 12Ö2

Mix "952" 2Ö2 "762 142 652 1772" 642 153.1 N 15 Ϊ5 15 15 15 15 H 15 116226 12

Example 1

Liquid porosimetry was used in both progressive and retrograde ways. During the running run, 5 samples were wetted with test fluid and the retracting portion was used to determine the fluid release properties. The cumulative volumes of the filled pores are shown in Figure 2. The pore beam range of 5-50µπι corresponds to a pressure range of 13200-1320 Pa. The cumulative void volumes at 10, 20, 30, 40, and 50 μm in percent (corresponding to pressures 6600, 3300, 2200, 1650, and 1329 Pa) are shown in Table III. The selection of this pressure range 10 is based on the estimated pressures used during the wiping procedure for various wiping applications (baby wet towel, household, etc.). Figure 2 and Table III show that the number of filled pores in the composite structure is smaller than in the reference sample. Thus, according to liquid porosimeter measurements, the release properties of the composite structure are superior to those of the reference sample.

15

Table ΙΠ.

Percent Filled Pore Sample # 10 in devil at 20 pm in 30 pm in 40 devil at 50 pm

Composite structure 2.83 6.54 14.10 26.42 43.84

Reference sample 5 ^ 96 1ÖJ7 20.50 39.22 72.18 • 4 · • · * «· ·: *. j Using the same measurement conditions, the maximum absorbance capacity of the composite structure at the end of the measurement was better than that of the reference sample (Figure 3).

20 ':: Example 2 hours »

Wipe test (wet sample) • ·> • · ·; The wipe test on wet samples showed a difference between the composite structure and * ·; * ’25 reference samples (Figure 4). The fluid release is higher for the composite structure than for the reference sample. For example, after three successive releases of I ♦ t, the composite structure retained about 10% less fluid than: "': reference sample.

30 116226 13

Wiping test (dry sample)

The wiping test on dry samples showed that the composite structure had a higher wiping efficiency (Figure 5). The composite structure is capable of absorbing 12.4% to 16.7% more fluid during the wipe test than the reference sample.

5 t «·» »· *» · · * i · »« 1 1 »* · • I · • 1 · • • • • • • • • • • • • • • • • • •

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* 1 t 1 • »* 1» * · • »«

Claims (18)

116226 Composite non-woven fabric formed from fibrous layers bonded together by layering the fibers, characterized in that the fibrous layers comprise a first 5 and a second outer layer, each comprising a mixture of hydrophobic and hydrophilic fibers, and also a first layer of hydrophobic fibers, and a second outer layer, the weight ratio of hydrophobic to hydrophilic fibers being 20:80 to 80:20 in the first and second layers, and the nonwoven having a pore volume distribution with at least 70% of the 10 total pore volume associated with pores having an effective radius greater than 125 µm. Composite nonwoven fabric according to claim 1, characterized in that the hydrophobic fibers are polyolefin fibers, such as polypropylene or polyethylene fibers. 15 Composite nonwoven fabric according to claim 1 or 2, characterized in that the hydrophilic fibers are selected from the group consisting of cellulose-based fibers such as viscose, cotton and cellulose fibers. . 20 Composite non-woven fabric according to any one of claims 1 to 3, characterized in that: • 1 ·; the hydrophobic fibers of the first and second outer layers are the same as • »· *>.:. interlayer. • t • «1 • · Composite nonwoven fabric according to any one of the preceding claims, characterized by f '; 25 that the fibers are carded staple fibers. Composite nonwoven fabric according to any one of the preceding claims, characterized in that the nonwoven fabric has a pore volume distribution of at least 30%. = Total pore volume associated with pores having an effective radius greater than 30 150 µm. • · I I · 1 t • 1 116226 Composite nonwoven fabric according to any one of the preceding claims, characterized in that the weight ratio between hydrophobic and hydrophilic fibers in the first and second outer layers is 30:70 to 70:30. Composite nonwoven fabric according to any one of the preceding claims, characterized in that the hydrophobic fibers in the first and second outer layers are polypropylene fibers and the hydrophilic fibers are viscose fibers, the hydrophobic fibers of the interlayer being polypropylene fibers. Composite non-woven fabric according to claim 8, characterized in that the first and second outer layers comprise polypropylene and viscose fibers in a weight ratio of 50:50. Composite non-woven fabric according to any one of the preceding claims, characterized in that the masses of the layers are 10-80 g / m 2. Composite nonwoven fabric according to any one of the preceding claims, characterized in that the fibrous layers consist of a first and a second outer layer and an intermediate layer. # <.i 20 12. Wiping product, characterized in that it comprises any of the preceding claims. ·,; composite nonwoven substrate. • «· •» • 1 t : 13. A wiping product according to claim 12, characterized in that it has a · · ....; wiping fluid such as an aqueous solution, emulsion, dispersion or lotion. ; ···; 25 I · · A wiping product according to claim 13, characterized in that the amount of liquid in the product is 2-5 g of liquid per gram of dry nonwoven substrate. • · »I» »» • I A method of making a composite nonwoven fabric according to claim 1,. · · '. 30 characterized in that it comprises the following steps:. forming a layered web comprising the first and second outer layers, both comprising a mixture of hydrophobic and hydrophilic fibers and an intermediate layer of hydrophobic fibers sandwiched between the first and second outer layers of 116226, wherein the ratio of hydrophobic to hydrophilic fibers in the first and second outer layers the layer has 20: 80-80:20, - hydroentangling of the layered web to bind the layers by fiber entanglement, and - drying the hydroentangled web. A method according to claim 15, characterized in that the layered web is formed by providing a first and a second web, both webs 10 comprising a mixture of hydrophobic and hydrophilic fibers and also a third web of hydrophobic fibers facing both the first and second webs. for depositing the web between the first and second web. Method according to claim 15 or 16, characterized in that the first, second 15 and third webs are carded webs made of staple fibers. A method according to any one of claims 15 to 17, characterized in that it comprises the additional step of adding liquid to the formed composite nonwoven fabric, preferably in an amount of 2 to 5 g per gram of composite nonwoven fabric. : 20 • · »• o ·» *> 17 1 1 6226