WO2003076179A1

WO2003076179A1 - Non-woven material with elastic properties

Info

Publication number: WO2003076179A1
Application number: PCT/EP2003/002312
Authority: WO
Inventors: Joergen Bech Madsen; Thomas Broch-Nielsen
Original assignee: Fibertex A/S
Priority date: 2002-03-11
Filing date: 2003-03-06
Publication date: 2003-09-18
Also published as: AU2003227036A1

Abstract

The invention relates to a non-woven material with elastic properties. According to the invention, the above either comprises a multi-layer composite with at least one layer in which fibres made from an elastic polymer are contained, or a homogeneous fibre mixture in which a proportion of the fibres are made from an elastic polymer.

Description

Non-woven material with elastic properties

The invention relates to a nonwoven material with elastic properties.

Because of their versatility and achievable unique product properties, nonwoven materials are widely used in a wide variety of applications. The nonwoven materials are used in the area of hygiene products, medical products, protective clothing, cleaning cloths, packaging materials, depth filters, automotive finishing materials, building materials and in many other areas. The function of the nonwoven materials in this application can be defined as follows:

- protection and barrier function;

- Liquid transport and absorbent properties;

- Filtration, separation or retention of particles;

- reinforcement.

One of the main disadvantages of the nonwoven materials according to the prior art, for example of needled or water-jet needled (spunlaced), spunbonded or spunmelted nonwovens, it is that these have no or only a very limited elasticity and elasticity. In addition, there is the problem that nonwoven materials according to the prior art, for example spun-melted composite products, lose their material properties, for example the liquid barrier function, when the material expands.

Increasing demands and needs of consumers and the market requirements derived from them lead to new requirements for nonwoven materials, whereby the following key parameters are important:

- new, consumer-oriented properties;

- higher performance and increased comfort at lower costs;

- Product flexibility for easier adaptation to the rapidly changing market trends and product designs;

- constant product quality;

- Economic manufacturing process for the provision of the nonwoven materials.

Various attempts have been made to provide nonwoven materials with elastic properties. However, only solutions were found which were very complex and therefore expensive and which were inadequate in terms of comfort and barrier properties. For example, polyurethane foam was used or an elastic film material was combined with the nonwoven material, this film material consisting of polyurethane. According to another solution, special polystyrene copolymers were used in the meltblown layer. Corresponding examples result from US 5,324,580. However, the use of such elastic films again has the disadvantage that there is very little or no breathability here. The use of polyurethane foam also means that the entire material is no longer breathable. In addition, the individual layers of the multilayer material are laminated offline in these known solutions, which leads to high production costs. The object of the invention is to provide a nonwoven material which on the one hand has elastic properties and on the other hand retains the usual advantages of nonwoven materials, namely breathability, barrier properties and tensile strength. In this context, barrier property is to be understood in particular as the liquid barrier property.

This object is achieved in that the nonwoven material consists either of a multilayer composite which comprises at least one layer in which fibers made of an elastic polymer are contained. On the other hand, the nonwoven material can also consist of a homogeneous fiber mixture in which a portion of the fibers consist of an elastic polymer.

With the present solution, elastic nonwoven materials can be made available in accordance with market trends, for example diapers, personal care products for women, protective mats, cushioning materials and others can be created through improved fit while maintaining the other properties. The fleece material can be adapted to the individual application in terms of elasticity, functional performance and costs.

Preferred embodiments of the invention result from the subclaims following the main claim.

Thus, the at least one elastic layer in a multilayer composite can contain bicomponent fibers and / or meltblown fibers in addition to the elastic fibers. The remaining layers can be polyolefin spunbond layers, needle felt layers, polyolefin meltblown layers or it can be spunbond layers which are subjected to stretching in order to likewise give them certain elastic properties. In this embodiment variant, as in the other embodiment variants, polyurethane, a polystyrene block copolymer, copolymers of polypropylene and polyethylene or elastomeric polypropylene (for example in accordance with US Pat. Nos. 5,594,080 A or 5,969,070 A) can be used as the elastic polymer. The elastic polymers can be used either alone or mixed with other polyolefins or polyesters (in compounds or blends) to reduce production costs or to make production easier.

Another preferred embodiment consists in that bicomponent split fibers are contained in the elastic nonwoven layer in addition to the elastic fibers. These bicomponent split fibers can be used, for example, as staple fibers or as continuous fibers or a combination of both. The unique properties of these fibers are that they split open on mechanical needles or water-jet needling (spunlacing) and form a layer of microfibers that can serve as a barrier layer or that can lead to the nonwoven material becoming even softer. In this embodiment variant, these split fibers and / or split spun threads are combined with other elastic fibers, for example staple fibers or spunbond threads or meltblown fibers, in order to form an elastic multilayer composite material or to create a homogeneous material with unique functional properties. One of the advantages is that these elastic fibers have a higher softness and a greater similarity to textiles, while at the same time they have improved wear resistance and at the same time provide a liquid barrier function or moisture transport function. The polymers used in the bicomponent split fibers can be, for example, thermoplastic polymers such as polyolefins, polyesters, polyamides or combinations of these.

Another embodiment of the present invention is that elastic staple fibers or elastic spun bond fibers or spun bond threads are used as elastic fibers.

The elastic fleece layer can be a liquid barrier layer, a liquid barrier layer advantageously being created here on the one hand and breathability retained on the other hand, which is the case when using polyurethane foaming or of films made of polyurethane, as has already been described in the prior art, was not guaranteed.

The surface weight of the entire nonwoven material can preferably be 7 g / m ² to 300 g / m ² . Preferably, the basis weight is but 7g / m ² to 150g / m ^2.

As far as it is a multilayer composite and a liquid barrier layer is present, these may preferably have a basis weight of 1g / m ² to 100 g / m ^2, said she but most preferably a basis weight of 1g / m ² to 50g / m ^2. In a further advantageous embodiment of the invention, in a multilayer structure, in addition to at least one meltblown layer with elastic fibers, polyolefin spunbond layers, needle felt layers and / or polyolefin meltblown layers are present.

The layers of the multilayer structure can be connected to one another by needling, water jet needling (spunlacing) or by thermal bonding (thermobonding).

The elastic properties of the respective elastic layers or of the entire elastic nonwoven material are achieved in that more than 5% by weight and preferably more than 10% by weight of elastic fibers can be contained.

One or more meltblown layers can be arranged particularly advantageously between one or more spunbond layers, so that, for example, the sequence SMS, SM, SMMS, SSMMS, SSMMSS results.

A further advantageous embodiment of the invention is that the weight per unit area of the multilayer structure is 7 g / m ² to 150 g / m ² , the elastic meltblown layers being 15 to 60% by weight and the spunbond layers containing 1 to 100% by weight of elastic polymers. Further details and advantages of the invention are described below using several exemplary embodiments:

In a first exemplary embodiment, an elastic, breathable nonwoven material with a textile-like surface and a liquid barrier function is described. The product weight, elasticity, tensile strength and barrier function can be tailored to be used, for example, in sealing leg cuffs or waist bands for wind or for protective clothing or other applications with a barrier layer. In this example, the nonwoven material consists of a composite material in which the elastic material is part of the liquid barrier layer. This is achieved by using elastic microfibers either in the form of meltblown fibers or split fibers as part of the barrier layer. Another application could also be the replacement of elastic films in hygiene products in order to achieve the same liquid barrier properties and the same elasticity with, however, significantly improved comfort, which makes this material particularly suitable for use in the manufacture of diapers.

A second example relates to an elastic nonwoven material with very high elasticity. The product weight, the elasticity and the tensile strength can also be tailored to the use as required, use here as a waist band for diapers, as protective clothing, as a component for the production of furniture or as bedding, where the elastic material is concerned serves to significantly improve the comfort and manageability of the material used. This is particularly the case when protecting corners or shapes with edges, whereby the material ensures a much better fit to these angular or angular areas. The nonwoven material can also consist of a multilayer composite in which the elastic material is combined with other nonwoven materials in order to improve the physical properties such as tensile strength and the external appearance. As a third example, a very loose elastic nonwoven material can be produced according to the invention, which has good stretching properties in different directions. The product weight, elasticity, tensile strength and a possible barrier function can be adjusted so that this material can be used as a replacement material for foamed material in cushions or upholstery materials for seats.

In a fourth exemplary embodiment according to the present invention, the nonwoven material according to the invention can be treated in such a way that it has hydrophilic properties on both outer sides. Product weight, elasticity and tensile strength as well as the hydrophilic property can be adjusted to use the material as an outer layer or material for clothing that fits better and is more comfortable to wear. The nonwoven material can be a multi-layer composite in which the elastic material is combined with other nonwoven materials in order to improve the physical properties, such as for example the tensile strength or the external appearance.

It is also possible to produce a staple fiber product that has at least 20% elastic fibers.

The multilayer composite can also have an elastic material with an eyelet layer for hooks and eyelet systems (Velcro tape), the eyelet layer being produced from a staple fiber product.

All nonwoven material constructions can be subjected to a so-called pre-stretching process, the pre-stretching being possible without or with simultaneous application of heat, the product being stretched either at room temperature or with the use of heat in the longitudinal and transverse directions or in a wide variety of directions.

According to a further exemplary embodiment, an elastic meltblown layer or an SMS material, where S for a spunbond layer and M for a Meltblown layer is used in a medium basis weight product to create a highly stretchable hygienic application, for example as a band, waist band, medical wound care products or others. Applications in the textile sector, for example for mattresses or seats, are also possible with this material.

However, the elastic meltblown material or the SMS material can also be used in a high basis weight application, in which case it is used in particular when reinforcing properties or durability are to be improved, for example in furniture, bedding or industrial applications.

According to one embodiment, one or more elastic meltblown layers can be connected to spunbond layers, for example in the form of SM, SMS, SMMS, SSMMS, SSMMSS or other layer compositions. The spunbond layer can in each case be made of polyolefin or polyester or it can be made of a bicomponent polymer which is based on a polypropylene and a polyethylene. It can also consist of polyolefin or polyester that is blinded or compounded with either bicomponent polypropylene / polyethylene or an elastic polymer such as polyurethane, polystyrene block copolymer or elastic polypropylene. The second spunbond layer in the example SSMMS does not have to be made of the same material as the aforementioned spunbond layer. Rather, one layer can consist of a standard polyolefin and two layers can consist of polyolefin mixed with elastic polymer. Elastic polymer is used in the spunbond layer because it further improves the elasticity. However, this addition is not absolutely necessary. The spunbond layer can also be made from polyolefin, which is stretched to obtain elastic properties.

According to a further exemplary embodiment, the multilayer composite can consist of one or more elastic meltblown layers, these having one or more spunbond layers by needling or water jet needling (spunlacing) are connected. The layers can additionally be connected to one another by heat treatment, ie for example by calendering or infrared heat treatment.

The spunbond layer can either be made from polyolefin or polyester or it can be made from a bicomponent polymer based on polypropylene and polyethylene. It can also consist of a polyolefin or polyester which is blinded or compounded with either bicomponent polypropylene / polyethylene or an elastic polymer such as. B. polyurethane, polystyrene block copolymer or elastic polypropylene. It is not necessary that all spunbond layers in, for example, an SSMMS material consist of the same material. For example, one layer can be a standard polyolefin and two layers can be a polyolefin blended with elastic polymer. In this example too, the elastic polymer is used to further increase the elasticity. Again, it is not necessary to add the elastic polymer. The spunbond layer can also consist only of polyolefin and be subjected to an appropriate stretching treatment in order to provide the elastic properties.

The two aforementioned multi-layer composites can be used with a low basis weight to create a stretchable liquid barrier material for those applications, for example as a leg sleeve for diapers or back material for diapers. With medium weight, they can be used as highly stretchable hygienic uses such as tapes, waist bands, alternatives to film material, basic medical care products. On the other hand, textile applications in mattresses, seats, etc. can also be possible. As an application with a high basis weight, reinforcement and other protective materials can again be provided in furniture construction, as bedding or in industrial applications.

The multilayer composite can consist of one or more elastic meltblown layers, which are connected to one or more needle felt layers by water jet needles (spunlacing) or needles are connected. The layers can additionally be connected to one another by heat treatment, for example by calendering or infrared heat treatment. These materials can be used in mattresses or as upholstery for furniture or car seats.

According to a further embodiment variant, the multilayer composite can consist of one or more elastic meltblown layers which are connected to one or more needle felt layers by water jet needles (spunlacing) or needling. The needle felt layers contain at least 10% elastic fibers in order to provide sufficient elasticity in the needle felt layers. The layers can also be connected to one another via heat treatment, for example by means of calendering or infrared heat treatment. The elastic fibers can consist of the same material as that previously mentioned for the spunbond layers. These multi-layer composites can be used in the manufacture of mattresses or upholstery for furniture or car seats.

According to a further exemplary embodiment, the multilayer composite can also represent a combination of the aforementioned examples, for example a meltblown layer with a spunbond layer and a needle felt layer can be connected by water jet needles (spunlacing) or a material with an SSMMS multilayer structure can additionally be connected to a needle felt layer by needles. Any other combinations are also possible.

According to a further exemplary embodiment, a combination of elastic staple fibers and split staple fibers and / or spunbond threads can be provided, which form an elastic fleece layer after spunlacing, whereby a very good liquid and particle barrier property and a very high degree of softness and drapability are created here. According to a further embodiment variant, a water-jet needled multilayer composite can be created from elastic meltblown layers or layers in combination with split fibers.

Spunmelted layers and spunlaced layers can also be combined to form a multilayer composite, which comprises split fibers and elastic meltblown fibers in addition to continuous spunbond threads. Both the surface and the added polymers can be modified in one of the above constructions, for example to create antistatic properties or very high liquid barrier properties. On the other hand, corresponding surfaces or polymer modifications in one of the above-mentioned constructions can serve to provide a nonwoven material with hydrophilic properties.

FIGS. 1 and 2 show a multi-layer composite in the form of a spunbond meltblown multi-layer composite, a layer structure SMMSS being selected here. The selected materials of the individual layers in the embodiment variant according to FIG. 1 correspond to those according to the prior art. If a corresponding multi-layer construction with a length L is stretched by a difference length Li in the direction of force F, corresponding cracks occur in the non-elastic meltblown layers, which are marked here with the arrows. Previously existing liquid barrier properties are destroyed due to these cracks, since liquid can penetrate through these cracks through the multilayer composite.

FIGS. 3 and 4 show an SMMSS material according to the invention, in which the meltblown layers with liquid barrier properties contain elastic components. With a corresponding force, which leads to an extension of the material by L], the entire material can stretch elastically without losing the corresponding liquid barrier properties. As shown here in Fig. 4, no cracks occur, so that the liquid barrier is not injured here. In the embodiment according to FIGS. 5 and 6, a multilayer composite is composed of two needle felt layers, between which a meltblown layer is contained. In the exemplary embodiment according to FIGS. 5 and 6, this is a meltblown layer according to the prior art, which has no elasticity and, when stretched in the direction F, is torn open in several places by the distance Li, as indicated by the arrows.

A corresponding material with an elastic meltblown layer according to the present invention is shown on the basis of FIGS. 7 and 8, in which the liquid barrier property is fully maintained, since no cracks occur here due to the elasticity of the meltblown layer.

FIG. 9 shows an enlarged representation of a nonwoven material according to the invention, this being an example of an SMMS structure which has a total weight of 10 g / m ² , where Si = S ₂ = ₄ g / m ² and M -ι = M ₂ = 1 g / m ² .

Claims

Non-woven material with elastic properties

1. fleece material with elastic properties,

characterized,

that it consists either of a multilayer composite comprising at least one layer containing fibers made of an elastic polymer,

or that it consists of a homogeneous fiber mixture in which a portion of the fibers consists of an elastic polymer.

2. Nonwoven material according to claim 1, characterized in that meltblown fibers are contained in addition to the elastic fibers in the elastic nonwoven layer.

3. Nonwoven material according to claim 1, characterized in that bicomponent fibers and meltblown fibers are contained in the elastic nonwoven layer in addition to the elastic fibers.

4. Nonwoven material according to claim 1, characterized in that bicomponent split fibers are contained in the elastic nonwoven layer in addition to the elastic fibers.

5. Nonwoven material according to claim 4, characterized in that elastic staple fibers or elastic spunbond fibers are used as elastic fibers.

6. Nonwoven material according to one of claims 1 to 5, characterized in that the elastic nonwoven layer is a liquid barrier layer.

7. Nonwoven material according to one of claims 1 to 6, characterized in that the basis weight is 7 g / m ² to 300 g / m ² .

8. Nonwoven material according to claim 7, characterized in that the basis weight is 7 g / m ² to 150 g / m ² .

9. Nonwoven material according to one of claims 1 to 8, characterized in that the at least one liquid barrier layer has a basis weight of 1 g / m ² to 100 g / m ² .

10. Nonwoven material according to claim 9, characterized in that the at least one liquid barrier layer has a basis weight of 1 g / m ² to 50 g / m ² .

11. Nonwoven material according to one of claims 1 to 10, characterized in that in a multilayer structure in addition to at least one meltblown layer elastic fibers polyolefin spunbond layers, needle felt layers and / or polyolefin meltblown layers are present.

12. Nonwoven material according to claim 11, characterized in that the layers of the multi-layer structure are connected to one another by needling, water jet needling (spunlacing) or by thermal connection (thermobonding).

13. Nonwoven material according to one of claims 1 to 12, characterized in that it contains more than 5% by weight and preferably more than about 10% by weight of elastic fibers.

14. Nonwoven material according to one of claims 1 to 13, characterized in that one or more meltblown layers (M) are arranged between one or more spunbond layers (S), for example in the order SMS, SM, SMMS, SSMMS, SSMMSS.

15. Nonwoven material according to claim 14, characterized in that the weight per unit area of the multilayer structure is 7 g / m ² to 150 g / m ² , the elastic meltblown layers being 15 to 60% by weight and the spunbond layers containing 1 to 100% by weight of elastic polymers ,

16. Nonwoven material according to claim 14, characterized in that the weight per unit area of the multilayer structure is 7 g / m ² to 150 g / m ² , the elastic meltblown layers being 15 to 60% by weight and the meltblown layers containing 1 to 100% by weight of elastic polymers ,