CA2268344A1 - Three dimensional needled non-woven absorbent composites - Google Patents

Abstract

A non-woven absorbent composite is provided for use mainly as disposable sanitary or medical article. The composite has at least two superimposed layer components. The upper layer is of suitable open fibrous structure and acts for liquid acquisition and distribution. The lower layer is of relative dense fibrous structure, preferably needled non-woven, and contains super absorbent material.
It acts as liquid storage. Super-absorbent fiber is used to assure the integrity of the system. The layers are bonded by needling. The whole system possesses a favorable three-dimensional absorbency profiles. The absorbent composite has integrated performance making it useful as all-in-one absorbent core.

Description

THREE DIMENSIONAL NEEDLED NON-WOVEN ABSORBENT COMPOSITES
Field of the invention The present invention relates to a three dimensional needled non-woven absorbent composite which is especially designed for use as disposable sanitary or medical article and which, thanks to its structure, has a plurality of advantages:
fast fluid acquisition, effective x-y distribution, minimum leakage or runoff, low rewet, low stain view ability, high absorbency capacity, dimensional stability, wet strength, no chemical binder, no shake off of absorbents powders and extreme softness.
Background of the Invention Absorbent structures used in sanitary napkins, diapers, incontinence pad and training pants have common requirements including sufficient absorbency capacity, fast liquid acquisition, rapid liquid distribution in inner structure, good liquid retention under load, low liquid run-off, smoothness and softness.
To meet the above mentioned requirements, the absorbent product usually consists 2 0 of different components such as a cover stock to provide clean and dry surface for the body skin, an .acquisition layer to quickly trap the insult liquid, a distribution layer to distribute the liquid to the full dimension of the absorption core, an absorbent core to absorb and retain the liquid, and an impermeable back sheet to prevent the leakage of the fluid out of the absorbent article. Substantial efforts have been made to improve the performance of each component. Improvements are being made continuously.
It has been realized that to control the liquid flow direction it is necessary to adopt 3-D (three dimensional) structure design. Perforated film (US Patent 3,929,135) 3 0 is a delicately designed cover stock with 3-D apertures having one way valve effect to reduce wet back. Flow control coversheet (US Patent 5,531,727) utilized the concept that in the porous structure, liquid tends to be sucked towards the finer pores. By arranging layered fibers from coarse to fine denier, a pore gradient in z direction is created. It is said that the flow control coversheet can improve the liquid struck through and reduce the wet back.

The current available absorbent cores are mainly special formulated cellulose fiber matrix or fluffy pulp. To large extent air-laid processing methods are utilized to produce this sheet type absorbent core. To increase the capacity of absorption and retention and to reduce the thickness of the products, super-absorbent polymer, normally in powder type, are added to the mixture. To get coherency and sufficient strength, the pulp sheet has to be compressed to certain density. With more super-absorbent polymer added, it is necessary to add thermal binding components, which has adverse effect on absorbency and material cost. In forming practical absorbent articles, the pulp sheet is either c-folded or multi-layered to achieve required absorption capacity. When used as multi-layer system, the pulp sheets would have different density and different super-absorbent content (US Patent 5,866,242). To overcome the conflicts of softness and reducing thickness, the pulp sheets some time need to be softened prior to its use by mechanically defibering (US Patent 5,814,034). The pulp type absorbents do have good wicking and fluid retention properties. However this type of absorbent always have a paper like stiff feeling. The major problems of the pulp absorbents may be low acquisition speed and high run-off, resulting in leaking napkins, which are due to the limitation of density of the pulp sheet. The pulp type absorbency sheet may achieve truly thin. But it -still needs the aids of acquisition or distribution components when fabricating the absorbent articles.
Peat moss composite board is also used as absorbent core. US patent 5,296,290 released an invention of combining a hydrophobic non-woven fibrous fleece materials with absorbent hydrophilic layer, preferably peat moss composite board.
The two layers are preferably bonded by needling. It was said that the penetrated fibers serve as wicks. The fluid can be carried away from the first layer to hydrophilic layer. The fibrous fleece may improve the liquid distribution speed for the whole system. However the peat moss board is quite stiff and has very low 3 0 wet strength and hydrophobic fibers having high surface tension have adverse effect on fluid acquisition speed of the absorbent composite Super absorbent polymer (SAP) is an efficient way to construct compact and efficient absorbent core. However the processing of such structure usually accompanies the problems of poor integration of SAP powder and fluffy pulp.
The SAP powders can have uneven amount over the surface of the core, can be shaken off the core, or finally move in the absorbent structure resulting in variable absorbency performance. SAP fibers have been developed for more than a decade.
But they have not really penetrated into the absorbent product market. Apart from the reason of price comparison with SAP powder, the other reasons are lack of technical know how for its processing methodology and performance design when combining with other fibers. Staple SAP fibers may be carded to web by traditional machinery mostly in conjunction with other staple fibers. However, not every bonding method is suitable for the web containing SAP fibers. The possible bonding techniques are thermal, chemical or needle bonding. But thermal and chemical bonding may adversely affect the product softness, cost, fluid behavior and absorption performance.
Summary of the Invention The object of the present invention is to solve in a very simple manner, the above mentioned, sophisticated absorption problems.
2 0 More specifically, the object of the present invention is to provide a novel non-woven absorbent composition with integrated performance of fluid acquisition, distribution and absorption, and also with improved flexibility. The main focus of the invention is of using staple fibers and super absorbent polymer fibers to built up three-dimensional structural composites which are suitable for feminine hygiene 2 5 products and other absorbent products.
In accordance with the invention, the above object is achieved with a liquid absorbent composite comprising at least two layers bonded by needle punching.
The fibers and web combination of the composite can be selected to meet any 3 0 predetermined needs.
The absorbent composite according to the invention comprises at least two layers including an upper layer consisting of a loose needled non-woven material forming a coarse fiber web having a liquid acquisition and transportation ability. The composition also comprises a lower layer consisting of a relative dense non-woven material having a liquid absorption and retention ability. The lower layer acts as an absorbent core and stores the liquid. Both layers are intimately combined by mechanical needling, also called needle punching, which provides transverse fiber tufts extending from the upper layers) to the lower layer(s).
The upper or "acquisition/distribution" layer is made of relative coarse fibers of 3 to 9 denier having a large pore size and volume and a low density ranging between 0.04 and 0.10 g/cm3. Thus, the upper layer provides fast liquid acquisition and transportation. At the same time, its porous structure acts as a reservoir and collects large amounts of incoming fluid, thereby reducing the liquid runoff.
The fibers of the acquisition layer are wet-able synthetic fibers to provide fast liquid transport in the fibrous structure and reducing the wet back.
The lower or "absorbent" layer (also called "core") consists of a needled non-woven material preferably made of SAP fiber, hydrophilic surface treated synthetic fiber and viscose. The density of the absorbent core is higher than that of acquisition layer, between 0.10 g/cm3 and 0.25 g/cm3.
Needling bonds the acquisition/distribution layer and the absorbent layer together.
The needling density is between 20 p/cmz (p/cmz stands for perforations per square centimer) and 100 p/cmz to give sufficient bonding and good z direction fiber tufts, which build up wicks to transport the liquid in contact with denser material where higher capillary force is available and the liquid absorption and retention values are high.
The fiber proportion in the absorption layer is selected to maximize the SAP
fiber absorption capacity, best utilize the fibrous pore storage capacity, and minimize the 3 0 cost. Rayon fiber provides the hydrophilicity. The synthetic fiber increases the compressive resistance of the absorbent core thus the retention capacity, and improves the gel-blocking problem.
The acquisition/distribution layer fiber web can be produced with a conventional textile carding equipment. A single denier fiber or multi-denier synthetic fiber system can be used to produce acquisition/distribution layers with different performance, e.g. low rewet, fast fluid transportation, good coverage etc. The web is needled to keep it lofty and soft. The fiber may range from 3 denier to 9 denier, 5 and its weight ranges from 20 gsm to 70 gsm (gsm stands for grams per square meter). The absorbent core is produced by traditional carding and needling procedure. To achieve thinner structure, heating and thickness calibration calendering can be used in line to produce the absorbent cores in one step.
The needling parameters for the absorption core and combination is arranged such that a density gradient from low to high in z direction is built up and the SAP
fiber is distributed more far away from the acquisition layer. The gradient density gives directional wicking effect. The far away arrangement of SAP fiber gives enhanced liquid retention to reduce rewet.
As another option, the composite includes the combination of needled non-woven material with pulp/SAP airlaid non-woven material. There are two types of needled non-woven material that can be used. One is the acquisition layer described above.
The other one is a blend of synthetic fibers and the SAP fiber. When combining the acquisition layer with the air-laid non-woven, the performance that is obtained is 2 0 similar to the one obtained with a needled non-woven composite, but the flexibility is not as good as with a needled non-woven composite. When combining synthetic/SAP fiber non-woven with the air-laid non-woven, the SAP selected has relative lower absorbent rate than that in the absorbent core. Thus the absorbent capacity increased without loosing other performance such as fast acquisition speed etc.
The composite has a desired flow pattern, i.e. insult liquid rapidly flows and spreads in the plane and fast penetrates to the web simultaneously. The reservoir effect dramatically improves the run-off performance under large flow rate insult.
3 0 The acquisition seed is also significantly increased. The needled non-woven absorbent composite is very soft comparing with available absorbent products.

The invention and its advantages will be better understood upon reading the following non-restrictive description of preferred embodiments of the invention, made with reference to the accompanying drawings.
Brief description of the drawings Figure 1 is a side elevational cross-section view of a liquid absorbent composite material according to the invention; and Figure 2 is a schematic representation of the equipment that was used for carrying out absorption tests.
Description of preferred embodiments of the invention As shown in the Fig. 1, the composite according to the invention comprises an upper acquisition layer 1 and a lower absorbent layer or core 2. Needling bonds the two layers. The needling provides vertical fiber tufts 4 that extend from the acquisition layer to the absorbent layer to form wicks. The density of the acquisition layer 1 is lower than the one of the absorbent core 2. The absorbent core 2 also has a density gradient, with a higher density in its lower part 3.
The liquid is easily trapped by acquisition layer 1 and quickly spreads in the x-y plane of the acquisition layer 1. The fiber tufts in the z direction provide a flow path and help the fluid to be absorbed by the absorbent core 2. The density gradient within the core 2 helps to retain the liquid away from the top surface.
The acquisition layer is made of coarse synthetic fibers and as of polyester, polypropylene polyamide etc., whose surface is hydrophilic treated. The fibers are in the range of 3 to 9 denier. More preferably, the fibers are 4 to 6 denier.
The acquisition layer has a basis weight of 30 gsm to 70 gsm. The fibrous web is needled to give coherence. The needling ranges from 30 p/cm2 to 100 p/cm2 3 0 according to the fiber blend to give a density ranging between 0.04 g/cm3 and 0.10 g/cm3. The coarse fibers avoid most of liquid rewet. Because the acquisition layer consisting of coarse fibers has larger pore size as compared to the substrate absorbent, it has a capillary break effect and it prevents the liquid absorbed being wet back. The fibers in the layer can be of identical denier or multi-denier.
In case of a blend of fibers with different sizes, the fibers should be hydrophilic surface treated to fasten the liquid through.
The absorbent core is made from a fiber blend of rayon, synthetic fiber and super absorbent fiber. The rayon fiber denier ranges from 1 to 4. The proportion of the rayon is between 20% to 50%. More preferred is 30%. The rayon fiber functions as reducing the liquid contact angle to enhance the capillary drawing force.
It was proved that more rayon may reduce the liquid retention because it is easily collapsed when wet.
The synthetic fiber has a denier range of 1.5 to 4 and is used at a proportion of 30% to 60%. The fiber could be polyester or polypropylene or the mixture of the two. The synthetic fiber should be treated with a hydrophilic spin finish.
Although there is difference between hydrophilic viscose fiber and the synthetic fiber in the liquid intimacy, the amount of the liquid hold in the viscose fiber is very small. Thus the absorbent and retention capacities depend largely on the pore volume and the capillary force created by the fibrous system. Therefore the synthetic fiber can be used. There are several benefits for the usage of synthetic fiber. First the synthetic fiber can increase the compressive resistance, thereof the liquid retention capacity.
Second, it may isolate the super absorbent fiber to avoid the gel locking.
Third, it can reduce the cost of the absorbent core dramatically.
The super absorbent fibers can be supplied by Camelot Technologies, High River Alberta, Canada, or Technical Absorbents, Grimsby, UK. In the absorbent core the 9 denier and 51 mm super absorbent fiber was used in proportion of 10% to 40%.
The above three fibers are mixed thoroughly before going to the card. After card and cross lapper, the web is needled from one direction. With the needles penetrating to the, web, fibers are carried through the web by the barbs on the needle. There are more inter-reaction between the bars and the fibers at the 3 0 needling side. Fibers are more densely packed at the needle entrance side.
Thus a fiber density gradient is formed; i.e. the fiber density is high at the needling side and low at the backside. It makes the one direction needled non-woven have distinct acquisition speed between the two surfaces. From the loose side the acquisition speed is about 2 to 3 times faster than that from the dense side.
Owing to the difference of fiber denier and the flex rigidity between the super absorbent fiber and the other fibers, the super absorbent fiber tends to stay at the needling side. At certain needling depth condition, this trend becomes more significant, i.e.
more super absorbent fibers are arranged at the dense side. This is another benefit when arranging the liquid flow and retention in one direction. The needling density ranges from 50 p/cm2 to 200 p/cm2. Needling penetration is between 9 and 1 1 mm. The needled non-woven's density is 0.1 g/cm3 to 0.25 g/cm3. To achieve thinner absorbent cores, post calender process can be applied. The traditional hot calender is an available way. The temperature is between 80 °C to 110 °C to avoid altering the softness of the absorbents. For instance one can use infrared heating plus cold calender on the needling line to increase the efficiency and productivity.
When using calendering compaction, the needling density and penetration conditions should be in the low side of the given range. The absorbent core can be from 100 gsm to 400 gsm depending on the absorbency capacity requirements.
The direction density gradient of the absorbent cone can also be achieved by utilizing multi-layer design. Each layer has different density where the lowest density layer is first in contact with the result liquid.
2 0 The acquisition layer and the absorbent layer are bonded together by needling. The loose side of the absorbent layer contacts the acquisition layer. In this way the fiber density is from low to high in z direction. Therefore the capillary force increases from the top to the bottom. With more super-absorbent fiber at the bottom, the liquid is hold away from the topside. The needling is conducted from the acquisition layer towards the absorbent core. The needling density is between 20 p/cmz and 50 p/cm2. This gives reasonable bonding and introduces fiber wicks to assist the fluid flowing towards the dense material. Thus a three dimensional absorbents structure is built up. The test shown that the integrated absorbents dramatically increase the liquid acquisition speed, and has superior low rewet, zero 3 0 runoff and extreme softness. The structure is very stable in both dry and wet state.
The combination also includes the acquisition layer described above and an airlaid non-woven made 'of pulp and super-absorbent fiber. The airlaid non-woven are selected with a soft handle. The two layers are bonded by the needling. The needles penetrate from the acquisition layer to the airlaid non-woven absorbent core with density of 20 p/cm2 to 50 p/cmz. The needling penetration varies from 6 mm to 9mm depending on the density of the airlaid non-woven and the needle used. By this arrangement, the acquisition layer is mechanically bonded with the absorbent core. The integration is therefore guarantied. At the same time the airlaid non-woven is softened to certain extent. The significant feature is that the acquisition speed increased dramatically.
When combining needled non-woven with airlaid non-woven, a proportion of SAP
fiber can be added to the synthetic fiber acquisition layer to balance the absorption capacity and using thinner airlaid non-woven. In this case, the needled non-woven has a basis weight between 7° and 150 gsm, SAP fiber proportion is from 5% to 25%. Preferably for low absorption rate, coarse SAP fiber is used.
The present invention is further illustrated by the following examples.
Example 1 The composite absorbent material was made with a needled non-woven acquisition layer and a needled non-woven absorbent core. The acquisition layer was made from 3 den polypropylene, with basis weight of 70 gsm, under 40 needling strokes/cm2 and 9 mm needling depth. A 150 gsm absorbent core was made of fiber blend of 9 denier super-absorbent fiber, 1.5 denier rayon and 2.5 denier polypropylene by proportion of 40%, 30% and 30% respectively. The absorbent core was needled at 80 p/cm2 and 11 mm depth before combining with the acquisition layer. The needling condition of 50 p/cmz and 7 mm depth was used in the combination.
Example 2 Another absorbent material was made of the needled non-woven composite with 3 0 similar structure to example 1. The acquisition layer was made of 6 denier polyester with the basis weight of 70 gsm. It was pre-needled at 50 p/cm2 and mm depth. The absorbent core was the same as the one in example 1 but with basis weight of 180 gsm.

Example 3 Another absorbent material was produced by needled non-woven composite. A 60 gsm acquisition layer was made of 75% 6 denier polyester and 25% 3 denier polypropylene. The absorbent core was of 170 gsm and the mixture of super-s absorbent fiber, rayon and polypropylene at the proportion of 30%, 30% and 40%
respectively. The absorbent core was pre-needled before compacted by traditional calendering. The two materials were combined by needling at 35 p/cmZ and 8 mm penetration.
10 Example 4 Another absorbent material was made of needled non-woven acquisition layer combining with an airlaid non-woven. The acquisition layer used was the same as the one in example 3. The airlaid non-woven had the basis weight 165 gsm. The fiber content included 30% super-absorbent. The rest fibers were viscose pulp and thermal bonding fiber. The needling condition used to combine the acquisition layer and the airlaid non-woven were 35 p/cmz and 9 mm depth.
Example 5 Another absorbent material was a combination of a needled non-woven as top layer and an airlaid non-woven as bottom layer. The top layer non-woven consisted of 25% super-absorbent fiber, 45% 6 den polyester and 30% of 3 den polyester.
The basis weight of the top layer was 120 gsm. In top layer. The airlaid non-woven contained 30% super-absorbent fiber, 55% pulp and 15% thermal bonding fiber.
The basis weight of the airlaid non-woven was 95 gsm. The two components were bonded by needling at 40 p/cm2 and 7.5 mm depth.
Comparison Example 6 This comparison example was one of top sale feminine napkins in the market. It was made of a perforated cover stock, acquisition layer, absorbent layer and an 3 0 impermeable back film. The acquisition layer is a pulp sheet (roughly 62 gsm). The absorbent layer was a c-folded pulp sheet. About 90 gsm super-absorbent powder was distributed in the interstice of the c-folded absorbent pulp sheet. For comparison with the above absorbent composite, the cover stock was removed before conducting test.

Comparison Example 7 This comparison example was the airlaid non-woven used in the example 5.
Comparison Example 8 The comparison example was a needled non-woven. It consisted of 65% of 1.5 den rayon and 35% of super-absorbent fiber. The basis weight and the density were 90 gsm and 0.08 g/cm3 respectively.
The examples were tested as follows:
Test liquid A specific synthetic menstrual liquid was used in the tests. The test liquid had the viscosity of 10 cps, surface tension of 70.3 dyn/cm and pH value of 10.5.
Liquid acquisition test The acquisition test method is a modified EDANA test method 150.3-96 for cover stock strike through property. The difference is that the current test method used Perspex plate with a central oval hole of size 13mm by 30 mm in each direction.
2 0 10 ml of test liquid was applied to the hole from 5 mm above the sample.
Weights were exerted to the Perplex plate to give 0.25 psi pressure over the entire surface of the sample during the test. The time required for the 10 ml test liquid being fully absorbed is called acquisition speed.
2 5 Liquid absorption The absorption test was conducted on a demand absorption tester. The test equipment is shown in the Fig.2. It comprises a constant pressure liquid supply vessel 1 1, incorporating a pressure compensation device 12 to maintain the liquid outlet pressure constant. A sample support 13 incorporating a support plate 14 is 3 0 connected to the liquid supplier 11. The support plate 4 is provided with a central hole having a diameter of 13 mm. The pressure compensation device is adjustable so that it can provide different outlet pressure. The absorption test used a 0 hydraulic pressure to test absolute demand absorption characteristics of the material. During the test, samples 15 were placed on the support plate 14.
After having been fully saturated, the samples were weighed. The absorbency capacity is the value of absorbed liquid amount divided by samples' dry weight.
Liquid retention The retention tests the sample liquid retention ability under certain pressure. The sample was saturated on the demand absorbency test rig before being transferred to a pile of standard filter papers. A plate with pressure of 1 psi was applied over the entire surface of the sample and maintained for 2 minutes. The sample was weighed to calculate the remaining liquid. The amount of the remaining liquid divided by the sample dry weight gives the retention capacity.
Wicking speed The wicking speed was obtained from the demand absorbency test. The time used by the liquid to fully spread to 100 cmz of the sample was recorded as the wicking speed.
Runoff The runoff test is from internal test method as well. A 3 cm x 3 cm sample was affixed on to a 45° plane. 2 ml of test liquid was applied on the near top edge of the sample in speed of 2 ml per second. The percentage of liquid runoff from the surface and edge of the sample is called runoff.
The results that were obtained are the following:

Examples Acqui- AbsorptionRetentionWicking Runoff sition capacity capacity speed speed Seconds g/g g/g Minutes Example 9 18.9 11.6 3.3 0 Example 4.5 16.0 10.0 7 0 Example 4.5 20.8 10.8 5.3 0 Example 7.6 19.6 10.1 4.5 0.1 Example 6.5 18.0 10.0 6 0 Example 45 12.2 10.8 4 25 Example 508 16.2 10.7 17 36.5 Example 328 26.0 12.1 20 0 As it can be seen in Table 1, the invented non-woven absorbent composites had dramatically increased the acquisition speed. The pulp materials in the comparison examples 6 and 7 should have very good absorption ability. The comparison needled homogeneous non-woven example 8 had relative large porosity. But none of them could absorb large amount of instant liquid insult in short period.
While with the invented absorbent composites, three-dimensional structure help to absorb large amount of instant liquid insult and distribute them into the absorbent core in very short time. This performance is very important for reducing the liquid runoff problem.
The absorption capacity results illustrate that the absorbent needled non-woven composites had superior absorbency capacity to the commercial product.
The retention capacity test results show that the presented three-dimensional absorbent composites had similar liquid retention capacity to the commercial product, single airlaid non-woven and single layer needled non-woven. It illustrates that the needled non-woven acquisition layer, although being loose compared with the absorbent core, did not diminish the liquid retention capacity of the whole system.

Liquid wicking speed results show that there are apparent difference between the multi-layer and single-layer structure. The composite absorbent had fast liquid spread speed in x-y plane. This was the contribution of the needled non-woven acquisition layer, which had large pore size to facilitate high linear and volume flow speed. Principally liquid is moved through the porous structure by gravity, the hydrostatic head of the liquid, and the drawing of the capillaries. The acquisition layer in example 1 relatively best balanced the pore size in capillary drawing and flow rate resulting in the fast liquid wicking speed.
Runoff is one of the major problems to be solved for the current sanitary napkin products. It can be seen from the Table 1 that none of the comparison examples could get zero runoff. With the presented absorbent non-woven composites, zero run-off had been achieved. The success was from the true three-dimensional absorbents structure. The liquid insult was effectively trapped by the needled non-woven acquisition layer and rapidly distributed in three-dimensional way to the absorbent core. The z direction wicks and the high capillary drawing of the absorbent core enhanced the absorption speed. Therefore the runoff was effectively controlled to zero.
All the presented absorbent non-woven composites had lower rewet than the comparison samples' rewet. One could easily feel difference between them. The surface of the insulted absorbent composites were very dry.

Claims (17)

1. A liquid absorbent composite comprising at least two layers, one of said layers hereinafter called "upper layer" consisting of a loose needled non-woven material having a liquid acquisition and distribution ability, another one of said layers hereinafter called "lower layer" being a relative dense non-woven material with a liquid absorption and retention ability, said at least two layers being joined together by needling, said needling providing transverse fiber tufts which extend from the upper layer to the lower layer.

2. The absorbent composite of claim 1, wherein said composite has an acquisition speed less than 10 seconds for SMF liquid.

3. The absorbent composite of claim 1 or 2, wherein said composite has no liquid runoff according to described test method.

4. The absorbent composite of any one of claims 1 to 3 wherein said upper layer is made of synthetic fibers of from 3 denier to 9 denier used alone or as a mixture where the coarse fibers are in a proportion over 70%.

5. The absorbent composite of any one of claims 1 to 3, wherein said upper layer consists of a mixture of synthetic fiber and super-absorbent fiber, said super-absorbent amounting to from 5% to 25% by weight with respect to the total weight of said upper layer.

6. The absorbent composite of any one of claims 1 to 5, wherein said upper layer has weight ranging from 30 gsm to 150 gsm and a density ranging from between 0.04 g/cm3 to 0.1 g/cm3.

7. The absorbent composite of any one of claims 1 to 6, wherein said upper layer is needled at a.density of 30 p/cm2 to 100 p/cm2.

8. The absorbent composite of any one of claims 1 to 7, wherein said lower layer is formed of a single or multi-layer, needled non-woven material.

9. The absorbent composite of claim 8 wherein said needled non-woven material consists of a mixture of viscose fiber, synthetic staple fiber and super-absorbent polymer fiber, the viscose fiber amounting to from 20% to 50%
by weight with respect to the total weight of said material and being of from 1.5 to 3 denier, the synthetic fiber amounting to from 30% to 60% by weight and being of from 1.5 to 4 denier, the super-absorbent fiber amounts to 10% to 40%.

10.The absorbent composite of claim 8 or 9 wherein said needled non-woven material has a weight ranging from 100 gsm to 4 gsm/1000 gsm.

11.The absorbent composite of any one of claims 8 top 10 wherein said needled non-woven material has the density ranging from 0.1 g/cm3 to 0.25 g/cm3.

12.The absorbent composite of any one of claims 8 to 11, wherein said needled non-woven material is needled at the density ranging from 50 p/cm2 to 200 p/cm2.

13.The absorbent composite of any one of claims 8 to 12, wherein said needled non-woven is hot calendered with a hot calendering machine or by online high infrared heating on cold caliper calendering.

14.The absorbent composite of any one of claims 1 to 7, wherein said lower layer is formed of a single or multi-layer airlaid non-woven material.

15.The absorbent composite of claim 14, wherein said air-laid non-woven material is produced from pulp and super-absorbent fiber.

16.The absorbent composite of any one of claims 1 to 16, wherein the lower layer is directionally needled and has a loose side in contact with the upper layer and

17 wherein said upper and lower layers are needled with needling density of from 20 p/cm2 to 60 p/cm2 and a needling penetration from 6 mm to 9 mm.
17.A sanitary napkin, incontinence pad, diaper, packaging or wound dressing consisting of an absorbent composite according to any one of claims 1 to 17.