Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
  • D04H1/541—Composite fibres, e.g. sheath-core, sea-island or side-by-side; Mixed fibres
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4282—Addition polymers
  • D04H1/4291—Olefin series
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
  • D04H1/541—Composite fibres, e.g. sheath-core, sea-island or side-by-side; Mixed fibres
  • D04H1/5412—Composite fibres, e.g. sheath-core, sea-island or side-by-side; Mixed fibres sheath-core
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/005—Synthetic yarns or filaments
  • D04H3/007—Addition polymers
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/08—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating
  • D04H3/14—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between thermoplastic yarns or filaments produced by welding
  • D04H3/147—Composite yarns or filaments

Definitions

• the present invention relates to a polyolefin-based recyclable nonwoven structure, methods for its production and uses thereof.
• nonwoven structures in various industries has become firmly established. These structures, which are typically composed of bonded and entangled fibres, offer a wide range of desirable properties including strength, durability, and flexibility. They are commonly utilized in various sectors such as healthcare, automotive, and construction, among others.
• nonwovens made from a single type of polymer often lack sufficient mechanical strength, flexibility, or resistance to chemicals or heat.
• nonwoven composites which consist of at least two different types of polymers, are frequently employed. These composites achieve improved properties through the synergistic effects of combining polymers. Examples include PP/PET nonwoven composites and PET/coPET nonwoven composites.
• DE102020114941A1 discloses a method for producing a wheel arch liner for vehicles, incorporating a process involving thermoforming a nonwoven semi-finished product made of high- and low-melting thermoplastic fibres.
• WO2016026875A1 discloses a method for manufacturing lightweight, durable luggage articles, specifically luggage shells, using a compacted, nonwoven sheet comprising randomly oriented, discontinuous reinforcing plastic fibres with a high melting point and randomly oriented discontinuous melting plastic fibres with a lower melting point.
• challenging mechanical applications e.g. a wheel arch liner
• the inventors have discovered that a predominantly polyolefin nonwoven structure can be prepared, which combines good recyclability with excellent mechanical properties.
• the product can be provided with a low density while maintaining mechanical properties even at low thicknesses (and thus surface densities), such that even challenging mechanical applications (e.g. use in wheel arch liners) are viable utilizing a very low weight of nonwoven.
• These polyolefin based nonwoven materials have the further advantage of possessing excellent chemical resistance, hydrophobicity and durability due to their high polyolefin content.
• a first aspect of the invention concerns a nonwoven structure comprising a plurality of entangled and bonded staple fibres, said nonwoven structure comprising:
• the polyolefins in the first polyolefin component and the second polyolefin component each comprise at least 90 wt.%, by total weight of the polyolefin, of the same first polyolefin monomer.
• the first polyolefin monomer is propylene.
• the first and second polyolefin component are comprised in a first polyolefin staple fibre which is a multicomponent staple fibre, preferably a sheath-core-type bicomponent fibre wherein the second polyolefin component forms the core of the fibre and the first polyolefin component forms the sheath of the fibre.
• the nonwoven structure comprising the first polyolefin staple fibres and third polyolefin staple fibres, said third staple fibres consisting of a third polyolefin component, wherein the third polyolefin staple fibre has a titer of 0.4-100 dtex, preferably 1-20 dtex, more preferably 2-15 dtex, and wherein the total combined amount of the first and third polyolefin staple fibres constitutes at least 80 wt.% of the nonwoven structure, preferably at least 90 wt.%, more preferably at least 95 wt.%, most preferably at least 99 wt.%.
• the weight ratio of first polyolefin fibre to third polyolefin fibre in the nonwoven structure is preferably in the range of 1:9 to 9:1, preferably in the range of 1:5 to 5:1, most preferably in the range of 1:2 to 2:1.
• the nonwoven structure comprising the first polyolefin staple fibres, third polyolefin staple fibres, and fourth polyolefin staple fibres,
• the nonwoven structure is preferably a sheet, such as a sheet having a surface density within the range of 200-5000 g/m 2 , preferably within the range of 500-2000 g/m 2 , and/or a thickness within the range of 0.5-10 mm, preferably within the range of 1 and 7.5 mm, more preferably within the range of 1.5 to 5 mm.
• the normalized modulus of the nonwoven structure is preferably higher than 750 MPa, more preferably higher than 900 MPa, more preferably higher than 1000 MPa , most preferably higher than 1150 MPa.
• the invention provides a process of preparing a nonwoven structure, said process comprising:
• the invention provides a nonwoven structure obtainable by the process described herein.
• the invention provides the use of a nonwoven structure according to the invention in a vehicle part, preferably a wheel arch liner, a door panel, an electric vehicle battery shield, an interior trim part, an air duct intake, a rear parcel shelf, a bumper or an underbody shield.
• Figure 1 illustrates various configurations of bicomponent fibres, such as the preferred embodiments of the first polyolefin staple fibre described herein elsewhere.
• the exemplary configurations shown in Figure 1 include side-by-side, segmented pie, islands-in-the-sea, tipped, segmented ribbon and sheath-core bicomponent fibres.
• the designs presented in Figure 1 are not exhaustive of all possible configurations.
• said ingredient may be absent.
• molecular weight refers to the number-average molecular weight, preferably the number-average molecular weight as determined by gel permeation chromatography.
• the staple fibres referred to herein may have been prepared via a multitude of methods, and the invention is not particularly limited in this regard.
• An example of a suitable method is melt spinning.
• the staple fibres can be solid or hollow, be round or shaped, e.g. multilobal such as trilobal.
• the staple fibres are round.
• polyolefin encompasses all forms of polyolefins, including different forms of stereoisomers (isotactic, atactic, syndiotactic) and is not particularly limited by the average molecular weight of the polyolefin. Preferred molecular weights are set out herein elsewhere
• polyolefin component refers to a plastic material comprising a majority (by weight) of polyolefin, but does not exclude the presence of additives which are commonly used in plastics such as antimicrobial agents (such as zinc oxide), plasticizers (such as phthalates, polymeric- and non-polymer plasticizers and adipates), flame retardants (such as aluminum trihydrate), fillers (such as fly ash, bottom ash, aluminum silicate, aluminum hydroxide, calcium silicate, magnesium silicate, dolomite, calcium carbonate, barium sulfate, calcium sulfate, hollow glass microspheres, soot, chalk, siloxanes or silica), reinforcers (such as glass fibers or minerals), pigments (such as carbon black) and/or UV stabilizers.
• additives which are commonly used in plastics such as antimicrobial agents (such as zinc oxide), plasticizers (such as phthalates, polymeric- and non-polymer plasticizers and adipates), flame retardants (such
• the polyolefin components referred to herein comprise at least 75 wt.% polyolefin, by total weight of the polyolefin component, preferably at least 80 wt.%.
• the polyolefin components referred to herein comprise at least 95 wt.% polyolefin, by total weight of polymers in the polyolefin component, preferably at least 98 wt.%, more preferably at least 99 wt.%, such as 100 wt.%.
• melting temperature is determined according to ISO 11357-3, preferably on a DSC Q2000 instrument by TA Instruments.
• the melting temperature refers to the peak of the melting range of a polymer of the second heating when applying the following temperature protocol under a nitrogen atmosphere:
• titer refers to the linear density of the staple fibre as determined according to ISO 1973:2021, preferably on a Favimat+ by TexTechno.
• a first aspect of the invention relates to a nonwoven structure comprising a plurality of entangled and bonded staple fibres, said nonwoven structure comprising:
• the density of the nonwoven structure may be within the range of 0.25-1.8 g/cm 3 , within the range of 0.25-1.5 g/cm 3 , or within the range of 0.25-1.3 g/cm 3 .
• the present inventors have found that excellent mechanical performance can be achieved without requiring high densities, thus the density may be within the range of 0.20-0.85 g/cm 3 , within the range of 0.20-0.7 g/cm 3 , or within the range of 0.20-0.6 g/cm 3 .
• the density is within the range of 0.20-0.75 g/cm 3 , within the range of 0.25-0.6 g/cm 3 , or within the range of 0.3-0.55 g/cm 3 .
• the density is higher than 0.3 g/cm 3 , preferably higher than 0.4 g/cm 3 .
• the plurality of staple fibres may have been entangled by a variety of methods. It is particularly preferred that the plurality of staple fibres have been entangled by needling or hydroentanglement, most preferably needling.
• the entangled and bonded staple fibres of the nonwoven structure may have been bonded in a multitude of ways. Suitable methods known in the art include chemical and/or thermal bonding, with or without the application of pressure during bonding. However, the inventors found that highly preferably, the entangled staple fibres have been thermally bonded, even more preferably thermally bonded with the application of pressure during bonding (i.e. heat- and pressure-bonded). As is known to the skilled person, heat- and pressure bonding is also referred to as "compression moulding". The exertion of pressure during the thermal bonding process contributes to achieving various properties described herein, including the density and mechanical properties of the nonwoven structure.
• the invention employs two polyolefin components having different melting temperatures and may employ further polyolefin components, as described herein elsewhere in more detail.
• various polyolefin components exist which have different melting temperatures.
• the melting temperature of polyolefin components is influenced by a multitude of factors including, but not limited to, the polyolefin method of synthesis (e.g., using a metallocene catalyst or Ziegler Natta catalyst), the polyolefin average molecular weight, the polyolefin stereoisomeric form, branching, crosslinking, the crystal structure, the use of fillers in the polyolefin component, processing applied to the polyolefin components (which include stretching or drawing down, annealing and crosslinking) etc.
• the polyolefin components described herein, in particular the first and/or second component are synthesized using a metallocene and/or Ziegler Natta catalyst.
• the polyolefin components described herein, in particular the first and/or second component underwent stretching, annealing and/or crosslinking, preferably stretching and/or annealing.
• the polyolefin in the polyolefin components employed in the present invention can be a homopolymer or a copolymer.
• the polyolefin is a copolymer
• it is preferably a copolymer prepared from at least two monomers selected from the group consisting of C 2 -C 5 alkenes, preferably selected from the group consisting of C 2 -C 4 alkenes, most preferably selected from the group consisting of C 2 -C 3 alkenes.
• the copolymer may be selected from an alternating copolymer, a random copolymer, a block polymer or a graft copolymer, preferably a random copolymer.
• the polyolefin in the polyolefin components described herein preferably has a propylene content of at least 80 wt.%, more preferably at least 85 wt.%, still more preferably at least 90 wt.%.
• the amount of monomers other than propylene is preferably 0.5-10 wt.%, preferably 1-8 wt.%, most preferably 3-8 wt.%.
• the polyolefin in at least one of the first and second polyolefin components is a copolymer, preferably a random copolymer, prepared from at least two monomers selected from the group consisting of C 2 -C 5 alkenes, preferably selected from the group consisting of C 2 -C 4 alkenes, most preferably selected from the group consisting of C 2 -C 3 alkenes, and having a propylene content of at least 80 wt.%, more preferably at least 85 wt.%, still more preferably at least 90 wt.%.
• the polyolefin in at least one of the first and second polyolefin components is a copolymer, preferably a random copolymer, prepared from at least two monomers selected from the group consisting of C 2 -C 3 alkenes (in other words, prepared from ethylene and propylene), and having a propylene content of at least 90 wt.%.
• the amount of monomers other than propylene, preferably the amount of ethylene is preferably 0.5-10 wt.%, preferably 1-8 wt.%, most preferably 3-8 wt.%.
• the polyolefins in the first polyolefin component and the second polyolefin component each comprise at least 90 wt.%, by total weight of the polyolefin, of the same first polyolefin monomer.
• the first polyolefin monomer is selected from the group consisting of C 2 -C 5 alkenes, preferably selected from the group consisting of C 2 -C 4 alkenes, most preferably propylene.
• the propylene content of the polyolefins in the first polyolefin component and the second polyolefin component is preferably at least 90 wt.%.
• the monomer contents referred to herein refers to the amount of said monomer relative to the total monomers used in the preparation of the polyolefin.
• the polyolefin components referred to herein have a numberaveraged molecular weight of 10-100 kDa, preferably 20-90 kDa.
• the melting temperature of the first polyolefin component is preferably in the range of 130-160 °C, most preferably in the range of 135-160 °C.
• the melting temperature of the second polyolefin component is preferably within the range of 140-180 °C, more preferably in the range of 140-170 °C, most preferably in the range of 150-170 °C, with the proviso that the melting temperature of the second polyolefin component is at least 10 °C higher than the melting temperature of the first polyolefin component.
• the polyolefin comprised in the polyolefin components referred to herein may be recycled.
• the nonwoven comprises a certain staple fibre
• the first polyolefin component and the second polyolefin component can be present in the nonwoven structure in the same or in different staple fibres.
• the first and/or second polyolefin component are comprised in a first polyolefin staple fibre.
• the first polyolefin staple fibre comprises at least 90 wt.% of the first and/or second polyolefin component by weight of the first polyolefin staple fibre, preferably at least 95 wt.%, still more preferably at least 99 wt.%.
• the first polyolefin staple fibre is a polyolefin staple fibre consisting essentially of the first and/or second polyolefin component.
• the first polyolefin staple fibre has a titer of 0.4-100 dtex, preferably 1-20 dtex, more preferably 2-15 dtex.
• the first polyolefin staple fibre preferably has an average length in the range of 10-200 mm, more preferably in the range of 20-150 mm, most preferably in the range of 30-100 mm.
• the first polyolefin staple fibre comprises the first polyolefin component
• the nonwoven structure further comprises a second polyolefin staple fibre comprising the second polyolefin component.
• the first polyolefin staple fibre preferably comprises at least 90 wt.% of the first polyolefin component by weight of the first polyolefin staple fibre, more preferably at least 95 wt.%, still more preferably at least 99 wt.%.
• the first polyolefin staple fibre is a polyolefin staple fibre consisting essentially of the first polyolefin component.
• the second polyolefin staple fibre comprises at least 90 wt.% of the second polyolefin component by weight of the second polyolefin staple fibre, preferably at least 95 wt.%, still more preferably at least 99 wt.%.
• the second polyolefin staple fibre is a polyolefin staple fibre consisting essentially of the second polyolefin component.
• the second polyolefin staple fibre preferably has an average length in the range of 10-200 mm, more preferably in the range of 20-150 mm, most preferably in the range of 30-100 mm.
• the weight ratio of first polyolefin fibre to second polyolefin fibre in the nonwoven structure is preferably in the range of 1:1 to 1:9, more preferably in the range of 1:1 to 1:5, most preferably in the range of 1:1.5 to 1:4.
• the first polyolefin component and the second polyolefin component are both part of the first polyolefin staple fibre.
• said first polyolefin staple fibre is a multicomponent staple fibre comprising the first polyolefin component and the second polyolefin component.
• the first polyolefin staple fibre is a multicomponent staple fibre comprising at least 90 wt.% of a combination of the first polyolefin component and the second polyolefin component by weight of the multicomponent staple fibre, preferably at least 95 wt.%, still more preferably at least 99 wt.%.
• the multicomponent staple fibre is a bicomponent staple fibre consisting essentially of the first and second polyolefin component.
• Figure 1 shows non-limiting examples of various possible configurations of a bicomponent fibre.
• Examples of such configurations include sheath-core-type fibres, side-by-side-type fibres or matrix-fibril-type fibres, each of which may be further subdivided into additional types.
• Bicomponent staple fibres are known to the skilled person.
• the first polyolefin staple fibre is a bicomponent fibre
• the first polyolefin staple fibre is preferably a sheath-core-type bicomponent fibre, wherein the second polyolefin component forms the core of the fibre and the first polyolefin component forms the sheath of the fibre.
• the weight ratio of the first polyolefin component to the second polyolefin component in the bicomponent staple fibre is preferably in the range of 1:1 to 1:9, more preferably in the range of 1:1 to 1:5, most preferably in the range of 1:1.5 to 1:4.
• the second fibre may be used, but this is not necessary.
• the nonwoven structure according to the present invention comprises
• the nonwoven structure may further comprise a third polyolefin staple fibre, said third polyolefin staple fibre preferably comprising at least 90 wt.% of a third polyolefin component by weight of the third polyolefin staple fibre, at least 90 wt.%, still more preferably at least 99 wt.%.
• the third polyolefin staple fibre is a polyolefin staple fibre consisting essentially of the third polyolefin component.
• the inclusion of the third staple fibre in the nonwoven structure can enhance the mechanical properties.
• the third polyolefin component preferably has a melting temperature which is at least 10 °C higher than the melting temperature of the first polyolefin component, preferably within the range of 140-180 °C with the proviso that it is at least 10 °C higher than the melting temperature of the first polyolefin component.
• the third polyolefin staple fibre has a titer of 0.4-100 dtex, preferably 1-20 dtex, more preferably 2-15 dtex.
• the third polyolefin staple fibre preferably has an average length in the range of 10-200 mm, more preferably in the range of 20-150 mm, more preferably the third polyolefin staple fibre has an average length in the range of 30-100 mm.
• the fourth polyolefin component preferably has a melting temperature at least 10 °C higher than the first polyolefin component, preferably within the range of 140-180 °C with the proviso that it is at least 10 °C higher than the melting temperature of the first polyolefin component.
• a lightweight nonwoven structure with excellent mechanical properties, such as stress at break or modulus may be provided when a fourth fibre is used and the titer of the fourth polyolefin staple fibres is significantly higher than the titer of the first fibre, whilst still maintaining favourable flexibility, making the nonwoven structure suitable for a multitude of applications.
• the use of a fourth fibre is highly preferred.
• the second and/or third fibre may be used, but this is not necessary.
• the fourth polyolefin staple fibre has a titer which is at least 150% of the titer of the first polyolefin staple fibre, preferably at least 200% higher than the titer of the first polyolefin staple fibre, more preferably at least 300%.
• the fourth polyolefin staple fibres have a titer in the range of 10-100 dtex, more preferably in the range of 25-90 dtex, most preferably, in the range of 50-80 dtex.
• the nonwoven comprises the first polyolefin staple fibres described herein and optionally comprises the second, third and fourth polyolefin staple fibres described herein. In all embodiments, it is preferred that
• the nonwoven structure according to the present invention can consist of various combinations of the four staple fibres mentioned hereinbefore.
• the total combined amount of the first, second, third and fourth fibres employed in the nonwoven structure of the present invention cannot exceed 100 wt.%.
• the nonwoven structure comprising the first polyolefin staple fibre and optionally the second polyolefin staple fibre wherein the total combined amount of the first and second polyolefin staple fibres constitutes at least 80 wt.% of the nonwoven structure, preferably at least 90 wt.%, more preferably at least 95 wt.%, most preferably at least 99 wt.%.
• the first polyolefin staple fibres are bicomponent fibres are described hereinbefore.
• the nonwoven structure may be free of the second polyolefin staple fibres (and thus consist essentially of the first staple fibres) or it may comprise the second polyolefin staple fibres.
• both the first and second polyolefin staple fibres are homopolymer fibres, such as polypropylene homopolymer fibres
• the nonwoven structure comprises both the first and second polyolefin staple fibres.
• the weight ratio of first polyolefin fibre to second polyolefin fibre in the nonwoven structure may be in the range of 9:1 to 1:9, such as in the range of 5:1 to 1:5.
• the weight ratio of first polyolefin fibre to second polyolefin fibre in the nonwoven structure is in the range of 1:1 to 1:9, more preferably in the range of 1:1 to 1:5, most preferably in the range of 1:1.5 to 1:4.
• both the first and second polyolefin staple fibres are homopolymer fibres, such as polypropylene homopolymer fibres
• the nonwoven structure comprises both the first and second polyolefin staple fibres
• the weight ratio of first polyolefin fibre to second polyolefin fibre in the nonwoven structure is in the range of 5:1 to 1:5, more preferably in the range of 2:1 to 1:2, most preferably in the range of 1.5:1 to 1:1.5.
• the nonwoven structure comprising the first and third polyolefin staple fibres, wherein the total combined amount of the first and third polyolefin staple fibres constitutes at least 80 wt.% of the nonwoven structure, preferably at least 90 wt.%, more preferably at least 95 wt.%, most preferably at least 99 wt.%, wherein the first polyolefin staple fibres are preferably bicomponent fibres are described hereinbefore.
• the weight ratio of first polyolefin fibre to third polyolefin fibre in the nonwoven structure is in the range of 1:9 to 9:1, preferably in the range of 1:5 to 5:1, most preferably in the range of 1:2 to 2:1.
• the nonwoven structure comprising the first, second and third polyolefin staple fibres, wherein the first polyolefin staple fibres preferably are bicomponent fibres are described hereinbefore.
• the nonwoven structure preferably comprises:
• the nonwoven structure comprising the first and fourth polyolefin staple fibres, wherein the total combined amount of the first and fourth polyolefin staple fibres constitutes at least 80 wt.% of the nonwoven structure, preferably at least 90 wt.%, more preferably at least 95 wt.%, most preferably at least 99 wt.%, wherein the first polyolefin staple fibres are preferably bicomponent fibres are described hereinbefore.
• the weight ratio of first polyolefin fibre to fourth polyolefin fibre in the nonwoven structure is in the range of 1:9 to 9:1, preferably in the range of 1:5 to 5:1, most preferably, in the range of 1:2 to 2:1.
• the nonwoven structure comprising the first, second and fourth polyolefin staple fibres, wherein the first polyolefin staple fibres preferably are bicomponent fibres are described hereinbefore.
• the nonwoven structure preferably comprises:
• the nonwoven structure may comprise further components such as further layers or skin (e.g. a textile woven, a spunbond nonwoven layer, a film layer, local reinforcements, etc.
• the nonwoven structure comprises at least 90 wt.% polyolefin staple fibres, by total weight of the nonwoven structure, preferably at least 95 wt.%, more preferably at least 99 wt.%, such as 100 wt.%.
• the nonwoven structure may be employed in an assembly where the nonwoven structure is combined with further layers or skins, for example by providing a textile layer on an outside surface of the nonwoven structure.
• the nonwoven structure contains little to no polymers other than polyolefins.
• the nonwoven structure comprises less than 10 wt.% of polymers other than polyolefins, by total weight of the nonwoven structure, preferably less than 5 wt.%, more preferably less than 1 wt.%, most preferably essentially none.
• the nonwoven structure as described herein, can be provided having excellent mechanical properties at a low density and thickness (leading to a low surface density).
• the nonwoven structure of the invention can further be provided with a high modulus.
• the normalized modulus of the nonwoven structure is preferably higher than 750 MPa, more preferably higher than 900 MPa, more preferably higher than 1000 MPa, most preferably higher than 1150 MPa.
• the nonwoven structure is surprisingly light, despite its excellent mechanical properties.
• the nonwoven structure preferably has a surface density within the range of 200-5000 g/m 2 , preferably within the range of 500-2000 g/m 2 .
• the thickness of the nonwoven structure may be varied depending on the use of said nonwoven structure.
• the thickness of the nonwoven structure is preferably within the range of 0.5-10 mm, preferably within the range of 1 and 7.5 mm, more preferably within the range of 1.5 to 5 mm.
• the nonwoven structure is provided in the form of a sheet, preferably a sheet having a surface density within the range of 200-5000 g/m 2 , preferably within the range of 500-2000 g/m 2 , and/or a thickness within the range of 0.5-10 mm, preferably within the range of 1 and 7.5 mm, more preferably within the range of 1.5 to 5 mm.
• the sheet preferably has a ratio of thickness (expressed in cm) to the surface area (expressed in cm 2 ) of one side of the sheet which is less than 0.01, preferably less than 0.005. As will be understood by the skilled person, the thickness is the smallest dimension of the sheet.
• the sheet may be shaped or curved, as is the case for example when the sheet is shaped like a wheel arch liner.
• the non-woven article preferably the sheet
• is curved this means that it is not flat.
• the non-woven article preferably the sheet
• is curved it is preferred that when the non-woven article is placed on a flat surface, the shortest distance between the non-woven article and the flat surface is at least 1 cm, preferably at least 10 cm at at least one location across the surface of the non-woven article.
• the nonwoven structure may be substantially riigid, such that the sheet may be a substantially rigid sheet.
• the nonwoven structure is prepared by means of heat- and pressure bonding, for example as described hereinafter.
• a second aspect of the invention relates to a process for preparing a nonwoven structure, preferably a nonwoven structure as described herein earlier, said process comprising:
• the nonwoven structure produced by the process of the invention is preferably the nonwoven structure described herein earlier.
• the plurality of staple fibres provided in step (a) of the process according to the invention is preferably as described herein before.
• the properties of the fibres described in the context of the nonwoven structure apply mutatis mutandis in the context of the entangled fibres before bonding.
• step (b) comprises heating the plurality of staple fibres to a core temperature sufficiently high to melt the first polyolefin component, but not substantially the second polyolefin component. This ensures bonding throughout the nonwoven structure.
• Said core temperature is preferably 130-170 °C, preferably 130-155 °C. It is important that the second polyolefin component, with a higher melting temperature, remains in a solid state throughout the process. This ensures that the nonwoven structure retains its integrity and does not lose its shape or structural integrity during the bonding process.
• the core temperature refers to the temperature of the core of the plurality of staple fibres, for example at half the thickness of the plurality of staple fibres.
• the methods for applying heat to melt the first polyolefin component are not particularly limited.
• ultrasonic radiation contact heating (e.g. by heated rollers), heated air, infrared radiation, etc. may be used.
• pressure is preferably applied to the staple fibres.
• the pressure is preferably maintained at least until the first polyolefin component has solidified, resulting in a nonwoven structure with bonded fibres.
• Pressure may be applied by any means known to the skilled person, including compression moulding, calendering or double belt pressing (e.g. using Teflon or steel belts).
• the heat- and pressure bonding of step (b) preferably occurs at a pressure that is at least 10 bar. More preferably, the pressure for the heat- and pressure bonding is at least 20 bar. Still more preferably, the pressure for the heat- and pressure bonding is at least 30 bar, yet more preferably at least 40 bar. These pressures contribute to a firm entanglement and bonding, resulting in a strong and durable nonwoven structure.
• the plurality of entangled staple fibres are maintained at a temperature sufficiently high to melt the first polyolefin component, but not substantially the second polyolefin component, for a period of at least 30 seconds, preferably at least 60 seconds, still more preferably at least 90 seconds.
• pressure is applied to the plurality of entangled staple fibres for at least 30 seconds. More preferably, at least 60 seconds.
• heat- and pressure bonding preferably takes place in a mould and is also referred to as compression moulding.
• the mould is typically made of a heat-resistant material such as metal or ceramic and has a specific shape and size to provide the desired shape of the nonwoven structure once bonded.
• the mould may also have a textured surface to create a pattern or design on the nonwoven structure.
• the mould used in the preferred process according to the invention is preferably curved such that the resulting nonwoven structure comprises one or more curves, i.e. it is not flat.
• the non-woven article preferably the sheet
• this preferably means that when the non-woven article is placed on a flat surface, the shortest distance between the non-woven article and the flat surface is at least 1 cm, preferably at least 10 cm at at least one location across the surface of the non-woven article.
• Nonwoven structure obtainable by the process
• Another aspect of the present invention is a nonwoven structure obtainable by the process described herein.
• said nonwoven structure is a nonwoven structure as described hereinbefore.
• a final aspect of the present invention pertains to the use of a nonwoven structure of the invention.
• the nonwoven structure may be used for various mechanically demanding applications.
• the inventors have found that the nonwoven structure is useful amongst others in a vehicle part.
• the vehicle part in this context, can be any component or element of a vehicle that is suitable for the incorporation of the nonwoven structure.
• the vehicle part is an air duct intake. In another embodiment, the vehicle part may be a rear parcel shelf.
• the use also encompasses a vehicle part that is a bumper. In yet another embodiment, the use further may comprise a vehicle part that is an underbody shield.
• the nonwoven structure according to the present invention is used as a wheel arch liner.
• the wheel arch liner is a component that is typically installed inside the wheel arch of a vehicle to protect the wheel well and other internal components from debris, water, and other external elements.
• the nonwoven structure is excellently suited for this application due to its mechanical properties, wherein a light weight is combined with high strength and recyclability.
• the nonwoven structures made solely of polyolefin components may provide advantageous acoustic and water-repellent properties.
• the nonwoven structures according to the invention have excellent mechanical properties.
• the normalized modulus is much higher than the PP/PET reference material, meaning that improved mechanical properties can be obtained with less material consumption.

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Citations (4)

• 2024
  • 2024-02-29 EP EP24160582.3A patent/EP4610416A1/fr active Pending
• 2025
  • 2025-02-27 WO PCT/EP2025/055296 patent/WO2025181207A1/fr active Pending

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