10 Composite Nonwoven Materials 1.4 Image of activated carbon and microfibre based composite nonwoven. partially densified web,composite nonwoven with two partially densified webs, and composite nonwovens with different functional particulate matters immobilized and microfibre webs in contact.Figure 1.4 displays a scanning electron microscopic image of activated carbon-particle-embedded microfibre composite nonwoven.Nowicka(2003)reported a series of composite nonwoven materials prepared by incorporating powder-sorbent particles such as carbon, chitosan and aluminium oxide in meltblown nonwovens.Kalayci et al.(2008) disclosed a composite nonwoven fabric consisting of elastomeric nanofibres and at least one type of active particle for the use as protective garments. 1.2.5 Hybrid composite nonwovens The hybrid composite nonwovens are prepared by combining nonwovens with other materials such as woven,knitted and braided fabrics,films,scrims,foams with tissue,etc.Qian(2007)developed a novel three-layer composite material by hydroentangling a woven fabric layer sandwiched between two nonwoven layers for the use as synthetic leather.Recently,Gensheimer et al.(2011)developed a polymer/bacteria composite nanofibre nonwoven by electrospinning of living bacteria by hydrogel microparticles for manifold new applications,including microbial fuel cells,biotechnical synthesis and environmental remediation. Nakamae and Shima(1984)described a hybrid composite nonwoven for acting as a substrate for artificial leather,which was prepared by hydroentangling three layers among which the first layer was a meltblown web of very fine fibres,the
10 Composite Nonwoven Materials partially densifi ed web, composite nonwoven with two partially densifi ed webs, and composite nonwovens with different functional particulate matters immobilized and microfi bre webs in contact. Figure 1.4 displays a scanning electron microscopic image of activated carbon- particle-embedded microfi bre composite nonwoven. Nowicka (2003) reported a series of composite nonwoven materials prepared by incorporating powder- sorbent particles such as carbon, chitosan and aluminium oxide in meltblown nonwovens. Kalayci et al. (2008) disclosed a composite nonwoven fabric consisting of elastomeric nanofi bres and at least one type of active particle for the use as protective garments. 1.2.5 Hybrid composite nonwovens The hybrid composite nonwovens are prepared by combining nonwovens with other materials such as woven, knitted and braided fabrics, fi lms, scrims, foams with tissue, etc. Qian (2007) developed a novel three- layer composite material by hydroentangling a woven fabric layer sandwiched between two nonwoven layers for the use as synthetic leather. Recently, Gensheimer et al. (2011) developed a polymer/bacteria composite nanofi bre nonwoven by electrospinning of living bacteria by hydrogel microparticles for manifold new applications, including microbial fuel cells, biotechnical synthesis and environmental remediation. Nakamae and Shima (1984) described a hybrid composite nonwoven for acting as a substrate for artifi cial leather, which was prepared by hydroentangling three layers among which the fi rst layer was a meltblown web of very fi ne fi bres, the 1.4 Image of activated carbon and microfi bre based composite nonwoven
Introduction to composite nonwovens 11 second one was made up of staple fibres,and the base layer was made up of woven or knitted fabric.Langley (1989)reported a multi-layered composite chemical barrier fabric,which was prepared by adhesive bonding of a nonwoven polypropylene fabric sandwiched between two layers of polymer multi-layered films.Paul and Kumar (1995)described a composite carpet-backing material consisting of a fibreglass scrim reinforced into two layers of nylon nonwoven fabric.Prodoehl et al.(2006)disclosed a multi-layer scrub pad comprising a spunbond scrubbing layer,an air-laid absorbent core layer and a laminated thermoplastic/cellulosic wiping layer. 1.2.6 Multi-formed composite nonwovens These can be manufactured by employing more than one forming section adding different fibres or filaments to the web.The processes include multi-card,multi- forming box air-lay,multi-forming box wet-lay,multi-beam spunbond,and multi- beam meltblown process,or combinations of various forming processes.Examples are SMS/SMMS/SSMMMSS composite nonwovens,CoForm composite non- wovens,prepared by a combination of carded,air-laid,and carded layers and bonded by the through-air bonding process.As known,the benefits of combining spunbond and meltblown webs are observed in surgical gowns,respirator filter, etc.(Russel,2007). Manning (1993)described a composite nonwoven material prepared by combining an air-laid nonwoven pulp web and a wet-laid bicomponent web layer by means of heat or chemical treatment.Angelini and Haley(2006)disclosed a composite nonwoven material which was prepared by combining a spunbond layer and a wet-laid layer and laminating thereafter for the use as a semipermeable membrane support.Jeambar(2009)disclosed a composite nonwoven fabric which was prepared by combining a carded web comprised of synthetic fibres and a wet- laid web of short natural fibres and then bonding by employing the hydroentanglement process.Homonoff et al.(1992)described a composite nonwoven fabric which was prepared by combining a spunbond web and a wet- laid fibrous web and bonding by employing the hydroentanglement process. Boscolo (2008)disclosed a composite nonwoven fabric prepared by hydroentangling a pre-consolidated spunbonded web,an absorbent pulp layer, and a carded or spunbonded cover layer. In another embodiment,Collins (1995)disclosed a composite nonwoven material prepared by hydroentanglement of a carded web and a series of spunbonded nonwovens.Bonneh (2006)developed a composite nonwoven fabric by combining a spunlaid continuous filament layer and a meltblown staple fibre layer and bonding them by means of hydroentanglement.Crainic (2005) disclosed a highbulk composite nonwoven prepared by combining a hydro- entangled binder fibre layer to a nonwoven layer issued from forming heads also consisting of binder fibres by means of the through-air bonding process
Introduction to composite nonwovens 11 second one was made up of staple fi bres, and the base layer was made up of woven or knitted fabric. Langley (1989) reported a multi- layered composite chemical barrier fabric, which was prepared by adhesive bonding of a nonwoven polypropylene fabric sandwiched between two layers of polymer multi- layered fi lms. Paul and Kumar (1995) described a composite carpet- backing material consisting of a fi breglass scrim reinforced into two layers of nylon nonwoven fabric. Prodoehl et al. (2006) disclosed a multi- layer scrub pad comprising a spunbond scrubbing layer, an air- laid absorbent core layer and a laminated thermoplastic/cellulosic wiping layer. 1.2.6Multi- formed composite nonwovens These can be manufactured by employing more than one forming section adding different fi bres or fi laments to the web. The processes include multi- card, multiforming box air- lay, multi- forming box wet- lay, multi- beam spunbond, and multibeam meltblown process, or combinations of various forming processes. Examples are SMS/SMMS/SSMMMSS composite nonwovens, CoForm composite nonwovens, prepared by a combination of carded, air- laid, and carded layers and bonded by the through- air bonding process. As known, the benefi ts of combining spun bond and meltblown webs are observed in surgical gowns, respirator fi lter, etc. (Russel, 2007). Manning (1993) described a composite nonwoven material prepared by combining an air- laid nonwoven pulp web and a wet- laid bicomponent web layer by means of heat or chemical treatment. Angelini and Haley (2006) disclosed a composite nonwoven material which was prepared by combining a spunbond layer and a wet- laid layer and laminating thereafter for the use as a semipermeable membrane support. Jeambar (2009) disclosed a composite nonwoven fabric which was prepared by combining a carded web comprised of synthetic fi bres and a wetlaid web of short natural fi bres and then bonding by employing the hydroentanglement process. Homonoff et al. (1992) described a composite nonwoven fabric which was prepared by combining a spunbond web and a wetlaid fi brous web and bonding by employing the hydroentanglement process. Boscolo (2008) disclosed a composite nonwoven fabric prepared by hydroentangling a pre- consolidated spunbonded web, an absorbent pulp layer, and a carded or spunbonded cover layer. In another embodiment, Collins (1995) disclosed a composite nonwoven material prepared by hydroentanglement of a carded web and a series of spunbonded nonwovens. Bonneh (2006) developed a composite nonwoven fabric by combining a spunlaid continuous fi lament layer and a meltblown staple fi bre layer and bonding them by means of hydroentanglement. Crainic (2005) disclosed a highbulk composite nonwoven prepared by combining a hydroentangled binder fi bre layer to a nonwoven layer issued from forming heads also consisting of binder fi bres by means of the through- air bonding process
12 Composite Nonwoven Materials Tai(2001)reported a continuous process for producing a composite nonwoven fabric by employing carding and air-laying processes of web formation.Also, it was claimed that a carded/air-laid/carded/carded composite nonwoven fabric can be produced by using the same process line.Doherty (2003)disclosed a composite nonwoven media for gas filtration application which was comprised of an electrically charged air-laid fibrous layer and a wet-laid fibrous layer. Manning (1993)developed a composite laminate including airlaid nonwoven pulp web layers reinforced by a wet-laid bicomponent web layer with or without addition of adhesive material in-between a bicomponent layer and the air-laid pulp web layer. 1.2.7 Multi-bonded composite nonwovens These composite nonwovens are prepared by a combination of nonwoven bonding processes.Examples include a composite nonwoven prepared by employing a combination of needle-punching and hydroentanglement or a composite nonwoven prepared by employing a combination of thermal bonding and adhesive bonding,etc.Orlandi (2005)reported a composite nonwoven fabric where a pulp layer was deposited onto a consolidated carded nonwoven before being coated with the super absorbent material and all these layers were finally thermo-bonded.Parikh et al.(2006)observed that a set of nonwoven fabrics bonded by a combination of needlepunching and hydroentanglement showed higher basis weight uniformity as compared to similar nonwoven fabric bonded by employing needlepunching only.It was reasoned that the hydroentanglement process redistributed the fibres near the holes created by needlepunching,thus improving uniformity. Kumehara(2003)made a patent disclosure of a composite nonwoven fabric of high strength and superior printability which was developed by intertwining the filaments of a stretched unidirectionally aligned nonwoven fabric and a dry nonwoven fabric by a needlepunching process,following which the two fabrics were unified by a thermal calendaring process.Neely and Oran(1995)disclosed a composite polyester nonwoven fabric for the use as a recyclable bale wrap prepared by employing combined thermal and needlepunching bonding technology. 1.2.8 Laminated composite nonwovens These can be manufactured by laminating many nonwoven substrates consisting of fibres or filaments of different types or species,or nonwoven substrates with other substrates,including woven fabric,knitted fabric,braided fabric,films and other materials.Gessner and Trimble (1998)disclosed a preferred embodiment where two outer nonwoven webs,comprised of oxidatively degraded spunbonded filaments,were laminated to a web of meltblown microfibres,thus forming a
12 Composite Nonwoven Materials Tai (2001) reported a continuous process for producing a composite nonwoven fabric by employing carding and air- laying processes of web formation. Also, it was claimed that a carded/air- laid/carded/carded composite nonwoven fabric can be produced by using the same process line. Doherty (2003) disclosed a composite nonwoven media for gas fi ltration application which was comprised of an electrically charged air- laid fi brous layer and a wet- laid fi brous layer. Manning (1993) developed a composite laminate including airlaid nonwoven pulp web layers reinforced by a wet- laid bicomponent web layer with or without addition of adhesive material in- between a bicomponent layer and the air- laid pulp web layer. 1.2.7Multi- bonded composite nonwovens These composite nonwovens are prepared by a combination of nonwoven bonding processes. Examples include a composite nonwoven prepared by employing a combination of needle- punching and hydroentanglement or a composite nonwoven prepared by employing a combination of thermal bonding and adhesive bonding, etc. Orlandi (2005) reported a composite nonwoven fabric where a pulp layer was deposited onto a consolidated carded nonwoven before being coated with the super absorbent material and all these layers were fi nally thermo- bonded. Parikh et al. (2006) observed that a set of nonwoven fabrics bonded by a combination of needlepunching and hydroentanglement showed higher basis weight uniformity as compared to similar nonwoven fabric bonded by employing needlepunching only. It was reasoned that the hydroentanglement process redistributed the fi bres near the holes created by needlepunching, thus improving uniformity. Kumehara (2003) made a patent disclosure of a composite nonwoven fabric of high strength and superior printability which was developed by intertwining the fi laments of a stretched unidirectionally aligned nonwoven fabric and a dry nonwoven fabric by a needlepunching process, following which the two fabrics were unifi ed by a thermal calendaring process. Neely and Oran (1995) disclosed a composite polyester nonwoven fabric for the use as a recyclable bale wrap prepared by employing combined thermal and needlepunching bonding technology. 1.2.8 Laminated composite nonwovens These can be manufactured by laminating many nonwoven substrates consisting of fi bres or fi laments of different types or species, or nonwoven substrates with other substrates, including woven fabric, knitted fabric, braided fabric, fi lms and other materials. Gessner and Trimble (1998) disclosed a preferred embodiment where two outer nonwoven webs, comprised of oxidatively degraded spunbonded fi laments, were laminated to a web of meltblown microfi bres, thus forming a
Introduction to composite nonwovens 13 spunbond/meltblown/spunbond composite nonwoven.Koczab(2001)developed a composite nonwoven material for the use in making absorbent hygiene products by assembling a synthetic fibre lap in-between two fluid-permeable nonwoven materials by means of thermal fusion. Howey and Martin (1996)described a laminated multi-layered composite nonwoven material that provided a liner for the magnetic recording medium in a computer diskette with superior wiping and hygroscopic dimensional stability and low debris characteristics.Manning (1993)disclosed a laminated composite nonwoven material comprised of an air-laid nonwoven pulp web reinforced by a wet-laid bicomponent web layer.Angelini and Haley(2006)described a laminated composite nonwoven comprised of a spunbond layer and a wet-laid layer and claimed that the resulting semi-permeable membrane provided an advantageous balance of properties,including smoothness,interlaminar adhesion and flux properties. Rudisill et al.(2003)disclosed a laminated composite nonwoven fabric comprised of a spunbond web consisting of composite fibres and a meltblown web consisting oflow density polyethylene fibres.Allgeuer etal.(2007)developed a composite nonwoven material by laminating propylene-based nonwoven layers made by the meltblown process.Ducker and Rangachari (2005)disclosed a composite nonwoven fabric prepared by laminating an air-laid absorbent core comprising cellulosic fibres and a nonwoven fabric layer consisting of polymeric fibrous material. 1.3 Processing,markets and applications Composite nonwovens are produced by a modern and innovative industry by employing nonwoven technology or an integration of nonwoven and allied technologies to bring together fibres and/or filaments of different types or species or characteristics.Combinations of different nonwoven,preforms or fabrics, prepared either by employing a variety of different process technologies or by combining nonwoven preforms or fabrics with traditional textile preforms or fabrics or scrims or foams or other materials into a consolidated structure,can also result in development of composite nonwovens.Also,integrating an embedded phase of particulates to a matrix phase of fibres or filaments forming a three- dimensional network around the particulates can lead to creation of composite nonwovens.Thus prepared composite nonwovens are providing engineered solutions by creating multi-functional products as well as economical solutions by eliminating many manufacturing processes and replacing two or more products by one product. Composite nonwovens are proving that innovative substrate,fibre combinations, and integration of process technologies are an increasingly beneficial option for new product developers(Wuagneux,2006).By combining the characteristics and performance features of different fibres and/or filaments and/or substrates
Introduction to composite nonwovens 13 spunbond/meltblown/spunbond composite nonwoven. Koczab (2001) developed a composite nonwoven material for the use in making absorbent hygiene products by assembling a synthetic fi bre lap in- between two fl uid- permeable nonwoven materials by means of thermal fusion. Howey and Martin (1996) described a laminated multi- layered composite nonwoven material that provided a liner for the magnetic recording medium in a computer diskette with superior wiping and hygroscopic dimensional stability and low debris characteristics. Manning (1993) disclosed a laminated composite nonwoven material comprised of an air- laid nonwoven pulp web reinforced by a wet- laid bicomponent web layer. Angelini and Haley (2006) described a laminated composite nonwoven comprised of a spunbond layer and a wet- laid layer and claimed that the resulting semi- permeable membrane provided an advantageous balance of properties, including smoothness, interlaminar adhesion and fl ux properties. Rudisill et al. (2003) disclosed a laminated composite nonwoven fabric comprised of a spunbond web consisting of composite fi bres and a meltblown web consisting of low density polyethylene fi bres. Allgeuer et al. (2007) developed a composite nonwoven material by laminating propylene- based nonwoven layers made by the meltblown process. Ducker and Rangachari (2005) disclosed a composite nonwoven fabric prepared by laminating an air- laid absorbent core comprising cellulosic fi bres and a nonwoven fabric layer consisting of polymeric fi brous material. 1.3 Processing, markets and applications Composite nonwovens are produced by a modern and innovative industry by employing nonwoven technology or an integration of nonwoven and allied technologies to bring together fi bres and/or fi laments of different types or species or characteristics. Combinations of different nonwoven, preforms or fabrics, prepared either by employing a variety of different process technologies or by combining nonwoven preforms or fabrics with traditional textile preforms or fabrics or scrims or foams or other materials into a consolidated structure, can also result in development of composite nonwovens. Also, integrating an embedded phase of particulates to a matrix phase of fi bres or fi laments forming a threedimensional network around the particulates can lead to creation of composite nonwovens. Thus prepared composite nonwovens are providing engineered solutions by creating multi- functional products as well as economical solutions by eliminating many manufacturing processes and replacing two or more products by one product. Composite nonwovens are proving that innovative substrate, fi bre combinations, and integration of process technologies are an increasingly benefi cial option for new product developers (Wuagneux, 2006). By combining the characteristics and performance features of different fi bres and/or fi laments and/or substrates
14 Composite Nonwoven Materials composite nonwovens are putting a new twist on the versatility,high performance, and quality that have come to be expected from nonwovens. Composite nonwovens are finding numerous applications including,but not limiting to,hygiene,wiping,medical,filtration,insulation,geotechnical, automotive,agriculture,apparel,home furnishing and packaging.The common products made with composite nonwovens include baby diaper,sanitary pad, adult diaper,household and personal wipes,absorbent pad,sterile wrap,wound care,face mask,surgical gown,drape,wound dressing,bandage,respirator filter, vacuum cleaner filter bag,HVAC filters,HEPA filters,automotive headliners, carpet,cabin air filter,agricultural coverings and seed strips,apparel interlining, footwear,bed mattress,wall coverings,window shades,carpeting and upholstery fabrics,etc. Composite nonwovens are already being used significantly in many markets,including hygiene,wipe,medical,filtration,automobile,geotextile, and agriculture.Wuagneux(2006)reported very interesting information on the usage of composite nonwovens in many of these markets.Hygiene has been the focus of composite nonwoven research for many companies looking to diversify in this market.Composite nonwovens are used in numerous hygiene products including baby care,feminine care,and adult incontinence products.In this direction,a significant amount of research,development,and commercialization has been taking place on combining nonwovens with films to meet the market's increasing demand for softness,comfort and production,or developing three- dimensional perforated laminate with aloe and cotton ingredients to meet the market's ever-increasing demand for better functionality. Besides hygiene,the wipes market has also seen increased usage of composite nonwovens.It has witnessed composite nonwovens prepared from a combination of webs made up of synthetic and natural fibres such as pulp or cellulose through hydroentanglement,needlepunching,thermal bonding or other technologies.The use of natural fibres resulted in enhancement of eco-friendliness and sustainability of the final product while multi-layer technologies can add benefits such as controlled absorption and release oflotion.Beyond hygiene and wipe,the medical market is known to be one of the significant users of composite nonwovens.They have played an important role in the medical market's quest to achieve a balance between comfort and protection.Besides,many industry experts believe that the EU regulations for drapes and gowns have driven the growth of multi-layered composite structures in Europe.The medical market has witnessed the success of many composite nonwoven materials which were produced by SMS technology, or combining multiple nonwovens (layers of different nonwoven technologies), or by combining nonwovens to films by using lamination technology.Another major contribution made to the usage of composite nonwovens is due to filter products.The filter market is aware of many developments of nano and micro- fibre based composite nonwovens for creation of novel air filter media,and it believes that these materials will play a major role in all segments of filtration in
14 Composite Nonwoven Materials composite nonwovens are putting a new twist on the versatility, high performance, and quality that have come to be expected from nonwovens. Composite nonwovens are fi nding numerous applications including, but not limiting to, hygiene, wiping, medical, fi ltration, insulation, geotechnical, automotive, agriculture, apparel, home furnishing and packaging. The common products made with composite nonwovens include baby diaper, sanitary pad, adult diaper, household and personal wipes, absorbent pad, sterile wrap, wound care, face mask, surgical gown, drape, wound dressing, bandage, respirator fi lter, vacuum cleaner fi lter bag, HVAC fi lters, HEPA fi lters, automotive headliners, carpet, cabin air fi lter, agricultural coverings and seed strips, apparel interlining, footwear, bed mattress, wall coverings, window shades, carpeting and upholstery fabrics, etc. Composite nonwovens are already being used signifi cantly in many markets, including hygiene, wipe, medical, fi ltration, automobile, geotextile, and agriculture. Wuagneux (2006) reported very interesting information on the usage of composite nonwovens in many of these markets. Hygiene has been the focus of composite nonwoven research for many companies looking to diversify in this market. Composite nonwovens are used in numerous hygiene products including baby care, feminine care, and adult incontinence products. In this direction, a signifi cant amount of research, development, and commercialization has been taking place on combining nonwovens with fi lms to meet the market’s increasing demand for softness, comfort and production, or developing threedimensional perforated laminate with aloe and cotton ingredients to meet the market’s ever- increasing demand for better functionality. Besides hygiene, the wipes market has also seen increased usage of composite nonwovens. It has witnessed composite nonwovens prepared from a combination of webs made up of synthetic and natural fi bres such as pulp or cellulose through hydroentanglement, needlepunching, thermal bonding or other technologies. The use of natural fi bres resulted in enhancement of eco- friendliness and sustainability of the fi nal product while multi- layer technologies can add benefi ts such as controlled absorption and release of lotion. Beyond hygiene and wipe, the medical market is known to be one of the signifi cant users of composite nonwovens. They have played an important role in the medical market’s quest to achieve a balance between comfort and protection. Besides, many industry experts believe that the EU regulations for drapes and gowns have driven the growth of multi- layered composite structures in Europe. The medical market has witnessed the success of many composite nonwoven materials which were produced by SMS technology, or combining multiple nonwovens (layers of different nonwoven technologies), or by combining nonwovens to fi lms by using lamination technology. Another major contribution made to the usage of composite nonwovens is due to fi lter products. The fi lter market is aware of many developments of nano and micro- fi bre based composite nonwovens for creation of novel air fi lter media, and it believes that these materials will play a major role in all segments of fi ltration in