INTC 2000: Dallas 26th -28th September 2000

P&G needs a more innovative nonwovens industry

P&G's purchases of nonwovens have increased by 50% since 1996 and should double in the next 3-5 years. By then their expenditure on nonwovens will be three times the 1996 levels. However the nature of the partnership between P&G and its nonwoven suppliers will have to change dramatically. To date P&G has emphasised the need for cost reduction over improvements in functionality and the development of innovative new materials. In future more new nonwovens will be needed, and P&G is likely to have fewer strategic development partners.

The successful ones will be those who can demonstrate:

• A track-record of innovation and speed to market

• Global reach: able to supply consistent materials wherever P&G launch products

• Minimum overlap of core-competences (with P&G?)

• Ability to collaborate with other P&G suppliers

Furthermore P&G would expect to see radical change over the whole of their supply chain. The successful partners would:

• Upgrade their R&D facilities to respond to the new challenge

• Install strong pilot-scale development facilities to speed up the flow of prototype materials for evaluation

• Would be capable of supplying identical materials regardless of source, i.e. nonwoven manufacturing plants had to become more standardised.

P&G for their part would also change:

• They would become more transparent to their suppliers, and provide clear success criteria (and feedback?)

• They would give the lion's share of business to the most innovative, not to the lowest cost producer.

• They would provide specifications based mainly on performance criteria which would be consistent globally

• Cost control, while taking second place to functional requirements would remain important: P&G want to eliminate all cost that does not contribute to a consumer-perceivable benefit.

This message to the nonwovens industry was summarised: If you can deliver breakthough performance advantages, P&G will take your innovation to the global consumer products market on a larger scale and faster than anyone else.

Thermal Conductivity Measurements

Paul Brady of American Nonwovens presented results of measurements of thermal conductivity on a variety of fibrous and feather waddings in a 50 0 C temperature differential. Ignoring everything but insulation value, it was clear that all organic materials of similar diameter performed similarly, as did all inorganic materials. There was no difference between chicken feathers and polyester for instance, down being only marginally better than either. Diameter and wadding density were the key factors, so the most cost-effective approach was to use the cheapest fibre in the lowest density to achieve the desired insulation value. In real consumer products, parameters other than insulation value (e.g. resilience, FR) were often important, and the choice of fibre would be affected by these factors.

OR Fabric Myths

Dr William Rutala of University of North Carolina Health Care System reviewed drapes and gowns from an infection control perspective and the problems arising from Surgical Site Infections (SSI's). The USA carries out 27 million surgical procedures a year. 15 to 18% of patients pick up infections while in hospital, and 66% of these infections are at incisions. Protection of the health care workers from blood-borne pathogens is equally important. 30% of surgeons and their first assistants still get skin contaminated with blood, as do 12% of other assistants and 4% of scrub nurses. The longer operations carry the highest contamination risk. Current drape and gown materials are clearly inadequate, Dr Rutala listing the myths as:

• The best products are chosen scientifically. Not so, one of the problems being the inability of current barrier performance test methods to predict in-use performance. The tests are not dynamic, make no attempt to simulate the wear and tear of a long operation, and take no account of the amount of blood that they have to withstand.

• Plastic reinforced gowns are impermeable. Not so, especially towards the end of a long procedure which could involve abrasion, tearing or puncturing of the gowns.

• Reusables offer better protection than disposables. Not so. A review of studies comparing the infection rates of disposables v durables showed that disposables had significantly reduced SSI's.

• Reusables are better for the environment. Not so. Life cycle analysis had shown that neither product was superior: both had environmental disadvantages, disposables being wasteful of raw materials and reusables having high impacts due to the washing procedures.

Even the economic case for reusables was debateable.

The best disposables from a barrier viewpoint were the laminates or “polypropylene treated” products, but there were many other factors to consider, not least the surgeons comfort (heat stress), the ability to move freely (drape) and to flex without linting.

Breathable Barriers

Tom Ryle of Clopay Plastic Products Company presented a survey of breathable materials patents, focussing on the microporous (continuous vapour pathways) variety rather than the monolithic (which work by sorption onto the wet face and desorption from the dry). Product patents outnumbered process patents by about 2 to 1, and the most patented applications were diapers and electrical. For diaper backsheets the favoured process appeared to be extrusion coating of a PP nonwoven followed by in-line incremental stretching to create the pores. This was now the largest and most active application area, with some 70% of diapers in the US , Europe and Japan using breathable backs. 100% penetration globally could be expected. Other applications listed were Clothing, Medical (drapes, gowns, wound-care, drug-delivery, sterile packaging), packaging (fruit and vegetables, moisture-venting packs e.g microwavable popcorn), printing, especially ink-jet (unique surfaces, ink absorbtion/durability, transparency/opacity) and Building (housewrap, roofing, flooring) Moisture vapour transmission rates of 1500-3000 gms/sq.meter/day were typical.

Skin Health under Diapers

Howard Maibach of the University of California School of Medicine Department of Dermatology described work on the effects of occluding skin with nonwovens used in diapering, femcare, incontinence pads, wound dressings etc. He pointed out that human skin is a micro-porous membrane with an important barrier-to-chemicals function which was suppressed by wetness. He thought the key to future diaper design was an understanding of the “invisible dermatology” of the skin, i.e. changes that occurred before damage became apparent. Instruments were now available to study this and could show that occluded skin was much more likely to be damaged by chemicals, for instance the surfactants used on coverstock. They could even show the onset of maceration caused by pure isotonic water. Breathability was therefore a good thing, but skin wetness was much more important than coverstock dryness. Wet skin absorbed more chemicals and was damaged by the chemicals in urine and faeces much more easily. He thought glove intolerance (contact urticaria, non-allergic contact dermatitis) suffered by surgeons, dentists and other regular glove wearers was a related problem. Here the answer seemed to involve providing gloves with an absorbent interlining. Asked if diapers with a (surfactant-free) absorbent interlining would be better he thought they would, the audience being left to deduce that this would only be the case before urination. The instruments used were a Trans-epidermal water loss meter to assess barrier function, a Laser-Doppler Flowmeter to assess sub-cutaneous blood flow, Capacitance measurement to assess skin wetness, and a Reflectance meter to detect the onset of erythema.

Effects of Humidity on Breakthrough Pressure

Y.K. Kamath of TRI on the effects of condensation on the breakthrough pressure. TRI's method for identifying the largest pore in a hydrophobic PP nonwoven involves forcing liquid up through a nonwoven until the first bubble of liquid appears on the surface. A graph of water pressure v. time indicates the precise breakthough pressure. Experiments to see if the humidity under which the nonwoven was conditioned affected this breakthrough pressure gave the expected result: higher humidity conditioning meant the sample was more easily wettable and breakthough occurred at progressively lower pressure. However on reconditioning back from the highest humidity tested (90%RH) to the lowest (20%RH) the breakthrough pressure remained at the lower level. Moisture regain curves were then plotted and showed an unusual hysteresis effect. PP moisture content rose from 0 to 0.4% between 0 and 90% RH, but remained at 0.4% when redried to 0%RH. The changes in breakthough pressure could be due to this hysteresis; wetted and dried PP being more wettable than the original polymer. A contribution from the audience suggested another possibility: the coverstock suffered a microscopic stretching during each pressurisation and did not relax on drying. The maximum pore size therefore became a little larger with each determination. The PP isotherms are nevertheless intriguing.

Improved Breathables needed

Joseph Palomo of Allegiance Healthcare reviewed the uses of breathable films in surgical fabrics. He concluded that while the films had penetrated the high-barrier gown market, improvements in comfort and cost effectiveness were needed to allow them to dominate. The most obvious way forward was the development of thinner films, simultaneously improving permeability and reducing cost. New breathable polymers could also yield improvements, as would nonwoven carriers specifically designed to support the films or coatings.

Two-Fibre Thermal Bonding Study

Hawthorne Davis (NCSU) described a thermally-bonded nonwoven as a set of bonds held together by bridging fibres. Thermal bonding must create strong bonds without weakening the bridging fibres. Experiments with pairs of fibres bonded at a single cross-over point allowed bond strength, fibre strength and visual appearance of the bond to be determined over a range of temperatures for three structurally different PP fibres.

• Fibervisions T196 – a PP homopolymer fibre with a degraded sheath - known to form strong bonds.

• As 1. but with spin-finish removed.

• A sheath-core PP bicomponent with a 3% ethylene/97% PP random copolymer sheath.

• A “bico” control made with the same PP polymer in both core and sheath with and without finish.

Several interesting observations were made:

• Polymer needs to flow to allow a strong bond, so the temperature at which bonding starts is also the temperature at which fibre strength begins to fall.

• Bonding is localised around the edges of the area of fibre overlap, and tends to be absent in the centre. This suggests bonding occurs where the pressure is low possibly indicating the Clapyron effect coming into play (Melting point increasing with applied pressure)

• Fibres with low birefringence sheaths (1,2 and 3) bond well at lower temperatures and allow the bridging fibres to maintain strength better.

• T196 without finish gives higher bond strengths.

There is an analogy with fibre structure here: point bonds being the equivalent of fibre crystalline regions, and the bridging fibres behaving as amorphous regions.

Finish Film stability

Theory predicts that any liquid film on a curved surface such as a fibre is unstable and is bound to collapse into droplets. Films of finish are no exception, their viscosity slowing down the collapse but having no effect on the maximum stable thickness of the film. On a 10 micron diameter fibre this was about 100 nanometers. Normal concentrations of finish would therefore be expected to form beads on the fibre surface rather than continuous films. Dr Thomas Theyson of Goulston Technologies used high speed photography to observe the finish application/drying process on moving polypropylene monofilament and multifilament yarns. He showed that on monfils, beading of the finish (Lurol NF-6004) only occurred above 0.5% add-on. On multifil yarns, due to the ability of the finish to accumulate in capillaries at fibre contact points, beading did not occur below 20% add-on.

Better Thermal Bonds with Weaker Fibres

Dr Gajanan Bhat's paper (UTK) on the effects of fibre morphology on the properties of thermally bonded PP nonwovens showed that stronger, highly-stretched fibres give the weakest thermal bonds. As-spun fibres (of the same diameter as the fully stretched ones) gave the best bond strengths, and better overall fabric strength. He concluded that the crystallinity of fully-formed fibres interferes with bond formation and their low extensibility prevents efficient load sharing between bonding points in the tensile tests. A significant increase in crystallinity of the as-spun fibres occurred in bonding, but due to the slow laboratory bonding process, this may be more than would be observed commercially.

Plasma for Wettability and Sterilisation

One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) could raise the surface energy of LLDPE film from around 30 dynes/cm (hydrophobic) to around 70 dynes/cm (hydrophilic) in one second. Unfortunately the effect is not durable and the surface energy decays to 50 dynes/cm in a few days. Longer exposure times increase the durability: 15 seconds allowing 70 dynes/cm to be maintained for weeks.

Dr Roth of the UTK's Plasma Sciences Laboratory also showed how diaper film (Linear Low Density PE) exposed for 5 minutes lost a half-micron of thickness, revealing exposed titania particles on the etched surface. Low density polyethylene etched more quickly (3 minutes) but the surface appeared to repair itself, becoming smooth again after 8 days storage. The contact angle of the film dropped from 105 o to 50 o in the first second of treatment. Polyester film contact angle could be reduced from 90 o to 15 o in 5 seconds treatment, but decayed to 40 o over 2 days of storage. Sterilization of surfaces is another consequence of OAUGDP treatment, survival curves for E. coli and Staph. aureus showing treatment times above 25 seconds being effective in completely disintegrating the bacteria. A novel air filter has been developed wherein melt-blown PP filter media can be sterilised by OAUGDP during use. In response to a question, Dr Roth said the effect of plasma treatment on cellulose remains to be studied.

Hydroentangling Spunbonds

Increasingly aggressive hydroentanglement processes are allowing increasingly novel nonwovens to be produced. Don Gillespie of Fleissner Inc. reported the successful hydroentangling of 17 dtex spunbond PP at 300 gsm but did not say at what speed. Other, presumably much lighter and finer-fibred webs have been entangled at 500m/min. Water pressures of up to 600 bar (8400psi) were being used, and were allowing the production of stable roofing membranes and coating bases, thereby removing the need for overbonding with hard latexes. Energy use in bonding ranged from 0.25 to 0.85 KwH/Kg. Sandwich structures comprising air-laid pulp between two spunbonds were allowing low cost wipes and absorbents to be produced. The most recent practitioners of the HE Spunbond art, Freudenberg, were however targeting conventional textiles with their splittable spunbonds being hydroentangled prior to textile dyeing, finishing and making up into garments. Spunlaced SMMS must be just around the corner.

PLA Development Update

Dr James Lunt's paper on Cargill Dow's PLA fibres was very similar to the Wakefield paper presented in June. The main points of interest were:

• $0.5 to $1.00/lb is still being quoted as the resin price from Blair.

• Concerns over the low melting point (for textile use) are being addressed by the development of a “stereocomplex with a crystalline melting point of 210 o C” This has interlocking D- and L- polylactide chains and is based on Dupont technology.

• Fossil-fuel energy use for the Blair plant was put at 57MJ/Kg (but could be reduced to 34 and then 5 if Blair switched to non fossil energy sources! A cellophane figure of 91, and a polyester figure of 76 MJ/Kg were mentioned, but not the comparable CIRFS figure of 54 MJ/Kg for viscose staple, which could also be reduced to single figures if non-fossil energy was used.)

• Apparel applications were clearly the main focus now, but PLA carpet tiles had been launched by Interface. (Resilience is good, but abrasion resistance is worse than regular polyester)

• Hohenstein comfort studies show PLA/Cotton sportwear laminates to be more comfortable that PET/Cotton laminates. (But PP/Cotton is the best?)

• The higher surface energy of PLA fibres leads to good wicking performance of unfinished fibres. (Could be useful in coverstock/ADL's)

• Lactus bacillus was the current fermentation organism, but others could be used.

• In extrusion, like PET, the polymer must be dry. It loses 10% inherent viscosity if processed with 100ppm water content.

PLA Fibres

Jeff Dugan (Fibre Innovation Technology) followed on to give the first nonwoven conference paper by one of CDP's development allies:

• PLA's key feature is that it is melt-spinnable while conferring some of the advantages of cellulosic fibres.

• Current prices are high but will fall into the “polyester-nylon” range when Blair is at capacity.

• The inherent wettability of PLA gives improved wet-laying and hydroentanglement.

• Its low refractive index means deeper and brighter dyeing than regular polyester.

• FIT has made a wide range of bicomponent fibres (skin-core, concentric and asymmetric, segmented pie, multi-core) and the multilimbed “4DG” shape using PLA. (USP 5,525,282 - June 11 th 1996 quoted)

• Carpet applications benefit from the resilience of PLA, but “tests are incomplete at the time of writing”.

• PLA burns but releases less heat and smoke than PET. It also shrinks very powerfully above its heat set temperature and so pulls away from flame.

• Its very good UV stability makes it good for window fabrics.

Jeff listed the main drawbacks of PLA as:

• Relatively poor abrasion resistance (but presumably better than cotton).

• Low melt temperature will limit it's use in higher temperature environments.

• Easy hydrolysis at conditions close to those used in commercial laundries and fabric finishing processes. It was being turned to advantage in the composting claims (hydrolyses wet at >60 o C). PLA could also be used as the “sea” in an islands in the sea bicomponent, and could be dissolved in 3 minutes in a commercial finishing process using hot 3% caustic.

• A “scroopy” handle. Unless corrected by surface finish this restricts resilience in wadding applications.

Meltblowing Biodegradable Polymers

Dieter Müller of the University of Bremen has attempted making meltblown nonwovens from polylactic acid, polyesteramide, polyvinyl alcohol, cellulose diacetate and a polycaprolactam/thermoplastic starch alloy. Polypropylene was the control. Only PLA and PEA (after adding 3% glycerol) gave fibrous webs like PP, but only PEA gave a nonwoven with usable strength. (PP meltblown was 40 times the strength, with 5 times the extensibility of the PLA and twice the strength, with one fifth of the extensibility of the PEA.) Neither PVOH, PC/TS nor cellulose diacetate, even with 10% glycerol added, would form fibres. Relative prices of the biodegradable polymers, with an appropriate health warning, were given as (c/lb) PP=0.35, PEA=1.4, PLA=0.75, CA=1.7, and PC/TS=1.9.

PTT Fibres

Donald Schiffler of NC State has tested webs of PTT, PET, Nylon, 50/50 PET/Nylon, 50/50 PET/PTT and also 90/10 PTT/PET in hydroentanglement and thermal bonding. Poly trimethylene terephthalate's inherent low bending rigidity enables it to form HE fabrics at lower bonding energy (<50kj/kg) than the others, and gives softer fabrics with comparable strengths at high energies. Calender bonding on the other hand gave poorer fabric strengths, the speaker concluding further development was needed to allow PTT to realise it's promise in this bonding system. Asked about potential applications for PTT in nonwovens Mr Schiffler thought it was probably premature to speculate, but woven and knitted applications were commercial. In latex bonding he would expect the fibre to behave like PET.

Nonwoven Structure

Several papers covered the use of image processing to characterise nonwovens, the most compelling being from Andrew Kallmes of MK Systems who is commercialising a procedure developed by Dr. Scharcanski at the Federal University of Rio Grande do Sol ( Brazil ) and C. Dodson at UMIST ( England ). Grey-scale images of any material could, in principle, be captured by any method e.g radiography or light microscopes. These were then scanned and digitised into some 65,000 pixels. The intensity of each pixel was compared with that of each of the nine surrounding pixels and computer analysis allowed the position and size of fibres and voids to be plotted. Polar diagrams appeared to give an accurate and quantitative representation of the structure of the nonwoven.

To Bead or not To Bead

Hollow sphere pigments made by Rohm and Haas for use in paints and papers could have applications in nonwovens. Michele Mlynar reviewed their production, uses and benefits. The production process was described as follows. An emulsion of acrylic acid and styrene is polymerised. A polystyrene shell forms around an acrylic acid core which on treatment with alkali swells and orients the shell radially. The resulting rigid beads are dried, air diffuses in, and the PS skin becomes completely impermeable, trapping a small amount of solid superabsorbent inside. One micron diameter beads have a core diameter of 0.82, their unique feature being that their 2 light-scattering surfaces yield a total refractive index equivalent to titanium dioxide while being effectively weightless. Even through paper industry super-calenders these beads stay spherical except at the surface where they flatten due to melting.

Ms Mlynar saw potential application in binders for nonwovens and presented the results of trials with 1 and 0.5 micron beads added to acrylic binders, one (non-ionic, Tg -11 o C) chosen to bond viscose webs and the other (Anionic, Tg +34 o C) chosen to bond polyester webs. HSP additions of up to 50% on binder solids were used. The expected significant opacity improvements were seen, tensiles were largely unaffected, but handle stiffened above the 20% add-on level especially on the viscose fabrics. At 20% add-on, the opacity of the 1oz/yd 2 nonwovens was around 5 percentage points higher with the 1 micron beads and 10 percentage points higher with the 0.5 micron beads (control fabrics had 43-45% opacity). In private conversation, Michele could not say whether the bead forming technology was capable of modification to allow the trapped SAP to be rewetted, or whether different polymers could be used.

Food Service Wipes

Bill Vogel of Atlantic Mills provided data on the US market for food-service wipes. 45.3% of the US spending on food goes to commercial, institutional or military establishments serving food. There are 831,000 of them, employing 11 million people and together they turnover $376 billion per year. Some details were available: $34billion was spent by institutional or military canteens, £35 billion by fast food outlets and $39 billion by full-service restaurants. About half of the adult population of the US eats out on a typical day. 80% of the wipes used are still textile, and of the 20% nonwoven, spunlace technology has the largest share. Nonwovens need to be robust enough to be used all-day in a wet, detergent and bleach laden environment with sanitizers containing chlorine and ammonia. Reducing the incidence of food-borne illnesses - e.g. E. coli, salmonella - has become a major driving force in wipe selection, the provision of sanitised nonwovens and the development of standardised cleaning procedures being appropriate responses to the problem. For instance, avoiding cross contamination between pre-cooked and cooked food areas requires the use of two different wipes, colour coded to allow them to remain separate. Combining nonwovens and bactericides is complex. The EPA's pesticides regulations can come into play and users must have a full appreciation of EPA requirements before selling a product or making claims. How long does it take to get EPA approval for a product? There is no set time, the process being continuous as the science and knowledge of sanitising surfaces evolves.

Developments in Carding

William Oxenham's (NC State) paper covered flat top cards for sliver production in some detail. They can now do 120 kg/hour/metre and the Reiter C51 is fitted with automatic card-wire grinding to reduce down-time and variability of web-quality between grinds. Roller cards achieve 600kgs/hr/metre and can reach speeds of 500 m/min on 0.9 dtex PP, but only 250 m/min on PET and 100 m/min on nylon. Suction transfers are needed to keep the webs on rolls and conveyors. Various manufacturers brochures were used to illustrate other systems.

Full List of Papers with Abstracts

“See above” indicates the paper is covered in the main body of this report

KEYNOTE SPEECH: NONWOVENS INNOVATION AND DEVELOPMENT FOR A GLOBAL CONSUMER PRODUCTS COMPANY:

Karl Michael Schumann: Director of New Platform Technologies – P&G. See Above

Schumann.km@pg.com

• IMPERFECTIONS OF COMMON NONWOVEN'S THERMAL RESISTANCE TEST METHODS

Lubes Hes - Technical University of Liberec

A series of nonwovens and wovens were compared for thermal conductivity using high and low emissivity contact plates. Nonwovens (low density fabrics) give lower results on more reflective contact plates. Thermal conductivity measurements should therefore include information about the optical properties of the measuring plates.

Lubos.hes@vslib.cz

• MODEL DEVELOPMENT FOR COST AND EFFICIENCY COMPARISON OF NONWOVEN, THERMAL INSULATION MATERIALS

Paul Brady - American Nonwovens - See main report

pbrady@amerinon.com

• ROLL PRODUCT MANUFACTURERS COST OF QUALITY

Paul Frost - PJ Associates

The use of control charts, statistical process control and experimental design (Taguchi) to control quality

pjfrost@pjassociates.com

• TWO-PARAMETER CHARACTERIZATION OF GLASS VEILS AND WIRES BY AIR PERMEABILITY TESTS

C. Heil - Owens Coming Veil Netherlands BV

Air-porosity measurements on standard wire-mesh test sieves allowed comparisons between predicted porosity (Ergun equation) and actual. Interesting graphs of porosity versus pore-diameter for the wires and various porous sheets.

mailto:Kees.heil@owenscorning.com

• DESIGN OF EXPERIMENT FOR PHYSICAL PROPERTY IMPROVEMENTS OF FIBERGLASS MAT

Toni Aldridge - Franklin International

The value of factorial experimentation rediscovered in the course of investigating the effects of binder level on the strength of glass mat.

614 445 1230

• ENGINEERED COMPOSITE PRODUCTS USED IN ADVANCED FILTRATION

Frank Cousant - Ahlstrom Technical Specialties, LLC

Data on filtration efficiency for different paper/nonwoven/fabric combinations. “The only limitation is the designers imagination”.

Frank.cousart@ahlstrom.com

• PAPER AND MELTBLOWN COMPOSITES - A REVIEW

Rowland Griffin - Monadock Nonwovens

Useful list of references (if you really want to try and replace paper with meltblown nonwoven.)

rgriffin@mpm.com

• NEW FILTRATION MATERIALS FOR THE NEW MILLENNIUM

Ed Homonoff- Edward C. Homonoff & Associates

Aerogels (for use in active filters), splittable fibres, and superabsorbent fibre filters reviewed (again).

Edward_ch@snet.net

• FILTRATION PROCESS IN ELECTROSTATICALLY CHARGED FILTER MEDIA

T. J. Ptak - Purolator Products. Inc.

An overview with theoretical treatment of particle capture mechanisms. No mention of the effects of the loss of charge in use though.

Thad_ptak@markivaft.com

• DESIGN OF COMPOSITE FILTRATION MEDIA USING FLOW POROMETRY

Krishna Gupta - PMI. Inc.

Six filter materials combined to make four composites: capilliary flow porometry helps the design process.

info@pmiapp.com

• 902 GLASS: A BIOSOLUBLE FIBER GLASS FOR AIR FILTRATION MEDIA

Foster Harding. Ph. D. - Johns Manville

A review of the problems and legislation related to inhaling glass fibre. 902 glass clears from the lungs faster than other glass fibres and has passed EU standards for low biopersistence.

flharding@mindspring.com

• REVIEW OF ASHRAE TEST RESULTS VERSUS REAL LIFE PERFORMANCE

Charles Kern - Johns Manville

Comparisons of glass and synthetic fibre filter media. Synthetics look good in the lab. but work less well in real-air where the electrostatic charge on the synthetic decays too quickly.

kernc@jm.com

• LARGE EDDY SIMULATION (LES) APPROACH FOR SOLVING FLUID DYNAMICAL PROBLEMS IN THE NONWOVEN FABRIC INDUSTRY

Ravi O.S. Prasad. Ph.D. - Fluent, Inc.

Computer modelling of fluid flow could help design of fibre distribution systems in air-lay, wet-lay and spun-lay processes.

rop@fluent.com

• USE OF GOWNS AND DRAPES IN HEALTHCARE

William A. Rutala, Ph.D., M.P.H, - University of North Carolina - See Above

919 966 1635

• APPLICATIONS AND REQUIREMENTS OF BREATHABLE MATERIALS

Tom Ryle - Clopay Plastic Products Co, - See Above

tryle@clopay.com

• NONWOVEN FABRIC OCCLUDED TO SKIN: EFFECT ON SKIN BARRIER-FUNCTION

Howard Maibach, M.D. - University of California Medical Center - See above

himjlm@itsa.ucsf.edu

• EFFECT OF CAPILLARY CONDENSATION ON BREAKTHROUGH PRESSURE OF NONWOVEN BARRIER FABRICS

Y. K. Kamath - TRI/Princeton - See above

ykamath@triprinceton.org

• BREATHABLE COMPOSITES FOR SURGICAL FABRICS

Joseph Palomo - Allegiance Healthcare -See above

palomoj@allegiance.net

• STRENGTH LOSS IN THERMALLY BONDED POLYPROPYLENE FIBERS

Hawthorne Davis - North Carolina State University - see above

919 515 6578

• SPINNING OF SUBMICRON STRUCTURE FIBERS

John Hagewood, Ph.D. - Hills, Inc.

Splittable and islands-in-the-sea fibre technology reviewed again. “Any size can now be produced at reasonable cost”

321 724 2370

• PRODUCTION OPTIMIZATION & CHARACTERIZATION OF SM & SMS NONWOVEN COMPOSITE CONTAINING BI-COMPONENT PP/PE MICRO-FIBER MELT BLOWN WEBS

Larry Wadsworth, Ph.D. - The University of Tennessee

When you increase the percentage of PP in a meltblown PP/PE bico, higher bonding temperatures and pressures are needed to make the SMS laminate. If it overbonds, increase the calender speed.

lwadsworth@utk.edu

• OPTIMIZATION OF PROCESSING CONDITIONS FOR A PP HOMOPOLYMER IN A REICOFIL SPUNBONDING PROCESS

Rammohan Nanjundappa - Colbond Nonwovens

4 hole sizes, 4 basis weights and 4 bonding temperatures analysed to give a strength response surface for a 35 MFR PP.

828 665 5039

• SPUNBONDING & SPUNLACING: TWO LEADING TECHNOLOGIES COMING TOGETHER

Alfred Watzl - Fleissner GmbH & Co. - See above

+49 06103 401 265

• DEVELOPMENT OF FINISHES FOR COTTON-SURFACED NONWOVENS FOR USE AS HOSPITAL OPERATING ROOM APPAREL

Christine Sun, Ph.D. - The University of Tennessee

Flurocarbon finishes improve repellency, soften the handle and reduce the abrasion resistance. Latex finish just improves the abrasion. FC on top of latex is a good compromise.

csun@utk.edu

• ROLE OF FIBER FINISH IN THE CONVERSION OF FIBER TO NONWOVENS:FINISH PERFORMANCE AS A MECHANICAL PROCESSING AID IN CARDING

Abdelfattah Seyam. Ph.D. - North Carolina State University

Finish levels from 0.36 to 1.36% were obtained by blending PP bales with 2%, 0.6% and 0.1% finish. 0.6% was also made by blending the high and low levels to achieve non-uniformity. 0.36% appeared to be the best level for web uniformity. Finish-on-fibre uniformity appeared irrelevant .

aseyam@tx.ncsu.edu

• THE STABILITY OF LIQUID FILMS ON HIGHLY CURVED SURFACES

Thomas Theyson, Ph.D. - Goulston Tech.. Inc. See above

ttheyson@goulston.com

• INFLUENCE OF SELECTED PROCESS PARAMETERS ON THE SOFTNESS OF LIGHTWEIGHT NONWOVEN FABRICS

Krishna Parachuru, Ph.D. - Georgia Institute of Technology

Data from panel, strength and Kawabata testing on 17 fabrics was correlated with production conditions. Regression equations were computed. Shear stiffness and fabric weight correlated best with panel assessment.

Krishna.parachuru@textiles.gatech.edu

• INCREASING THE SURFACE ENERGY & STERILIZATION OF NONWOVEN FABRICS BY EXPOSURE TO A ONE ATMOSPHERE UNIFORM GLOW DISCHARGE PLASMA (OAUGDP)

J. Reece Roth - The University of Tennessee - See above

865 974 4446

• ENHANCING THE SPREADING PERFORMANCE OF FINISHES

Mark Nehra - Uniquema

Their new ESC technology allows more even application of lower levels of finish on fibre by “expert formulation of the spin-finish component chemistry available”

Mark.nehra@uniquema.com

• LOW-BORON FIBERGLASS FORMULA FOR HIGH EFFICIENCY MICROGLASS FILTER MEDIA

Jack Xu - Johns Manville

For use in semi-conductor clean room air-filters to avoid boron contamination of the silicon wafers.

xux@jm.com

• USE OF INFRARED THERMOGRAPHY TO IMPROVE THE MELT SPINNING AND PROCESSING OF POLYESTER FIBERS

Glenn Gibson - Eastman Chemical Co.

Being able to see temperature differences helps eliminate them. Views of the filaments in the quench zone show the variability (45-70 o C) we always suspected.

gdgibson@eastman.com

• NONWOVENS FROM POLY (TRIMETHYLENE TEREPHTHALATE) STAPLES

Don Shiffler - North Carolina State University - See above

dschiffler@tx.ncsu.edu

• MELTBLOWN FABRICS OUT OF BIODEGRADABLE POLYMERS

Dieter H. Mueller. Ph.D. - BIK/Universitv of Bremen - See above

bik@bik.uni-bremen.de

• IMPLICATIONS OF FIBER MORPHOLOGY ON THE: STRUCTURE & PROPERTIES OF THERMALLY BONDED POLYPROPYLENE NONWOVENS

Gajanan Bhat - The University of Tennessee - See above

423 974 0967

• CHARACTERIZATION OF COTTON/CELLULOSE ACETATE NONWOVENS OF UNTREATED & AQUEOUS PRETREATED WEBS PRIOR TO THERMAL BONDING

K. E. Duckett - The University of Tennessee

More on the calendering of wet- acetate (as at INDA-TEC 99). Water acts a plasticiser and lowers the bonding pressure. Some internally plasticised fibres are beginning to appear.

kduckett@utk.edu

• EFFECT OF BIAS ANGLE ON THE MECHANICAL PROPERTIES OF STITCH-BONDED FABRIC

Vladimir Lasic - University of Zagreb

MD testing gives the highest results, CD the lowest. Strength and extension variations are inversely related. Honestly.

Vladimir.lasic@public.srce.hr

• THEORETICAL DESIGN OF NONWOVEN FABRICS

Peter P. Tsai. Ph.D. - TANDEC

Calculated and actual values of pore-size and permeability are in agreement for meltblown but not for needlefelts (because pore size could not be measured). Filtration efficiency of multilayer structures can be deduced from measurements of the components. Strength can be calculated from the fibre orientation distribution function.

ppytsai@utk.edu

• CHARACTERIZATION OF STRUCTURAL CHANGES IN NONWOVEN FABRICS DURING LOAD-DEFORMATION EXPERIMENTS

Behnam Pourdeyhimi,. Ph.D. - North Carolina State University

Image capture and analysis during a tensile test. MD/CD orientation increases under load, and bond points get narrower. This has nothing to do with bonding temperature in calendering, and everything to do with the original MD/CD orientation.

bpourdeyhimi@unity.ncsu.edu

• NONWOVENS IN BATTERY SEPARATORS

John G. McCulloch,Ph.D. - Nonwoven/MB Ind.

A useful history of battery and fuel cell development with 39 references and 100+ patent numbers.

Jmccul3504@aol.com

• POLYLACTIDE POLYMERS: TECHNOLOGY AND APPLICATIONS

James Lunt, Ph.D. - Cargill Dow LLC - See above

Jim_lunt@cdpoly.com

• NOVEL PROPERTIES OF PLA FIBERS

Jeff Dugan - Fiber Innovation Tech., Inc. - See above

jdugan@fitfibers.com

MICROSTRUCTURAL ANALYSIS OF FIBER SEGMENTS IN NONWOVEN FABRICS USING SEM & IMAGE PROCESSING

HK Versteeg - Loughborough University

More on image analysis to get the fibre orientation distribution of HE nonwovens. Much testing but no correlations drawn. The joy must be in the travelling.

h.k.versteeg@lboro.ac.uk

• DETERMINING FIBER ORIENTATION DISTRIBUTIONS IN NONWOVENS WITH HOUGH TRANSFORM TECHNIQUES

Bugao Xu - University of Texas @ Austin

As for 42, with less travelling and more mathematics.

bxu@mail.uxtexas.edu

• DEVELOPMENTS IN ABSORBENT PRODUCTS AND THEIR IMPACT ON THE NONWOVENS INDUSTRY

Colin White - MCW Technologies

The history of baby diaper development. “Future development will have a major impact on the nonwovens business as a whole. It is to be hoped that this impact will prove to be generally beneficial…)

Cwhite4617@aol.com

• FOOD SERVICE WIPES

William Vogel - Atlantic Mills. Inc. - See above

732 363 9281

• SPREADING & COALESCENCE OF LIQUID DROPLETS ON NONWOVENS

Xuemin Chen - TRI/Princeton

More high-speed photography of finish droplets on single and paired filaments. Films tend to coalesce into droplets and droplets tend to migrate to cross-over points. If crossing angles are small the liquid stays as 4 triangular films, but if large, one large droplet forms. The critical angle increases with increasing fibre surface energy.

xchen@triprinceton.org

• UNIFORMITY & ANISOTROPY IN NONWOVEN FIBROUS MATERIALS

Andrew Kallmes - MK Systems - See above

paul@mksystems.com

• FLAME RETARDANT CHEMICAL TREATMENTS FOR NONWOVENS

James R. Johnson, Ph.D. - Olympic Laboratories, Inc.

FR additive choices for different nonwoven applications in composites. (Short paper with no conclusions.)

Drj007@bellsouth.net

• CHEMICAL APPLICATION BY FOAM: ONE PRACTICAL AVENUE TO NEW PRODUCTS

Christoph Aurich - Gaston Systems, Inc.

The advantages listed: mainly more uniform add-on, low wet pickup and easier drying, less migration to fibre cross-over points, all contributing to lower costs, higher speeds and less pollution.

gastonsys@aol.com

• HOLLOW SPHERE PIGMENTS: DO THEY HAVE A PLACE IN THE NONWOVEN INDUSTRY?

Micbele Mlynar - Rohm & Haas Co. - See above

Michele_f_mylnar@rohmhaas.com

• CROSS-FLOW DRYING & CURING OF WET-LAID GLASS FIBER VEILS

C. Heil, Ph.D. - Owens Coming Veil Netherlands BV

Mathematical modelling of the drying process compared to actual performance. Deeper insights into drying were obtained.

Kees.heil@owenscorning.com

• DEVELOPMENTS IN CARDING

William Oxenham - North Carolina State University - See above

919 515 4552

OPTIMISATION OF ENERGY TRANSFER IN HYDROENTANGLEMENT PROCESS

M. Acar - Loughborough University

Effects of water pressure on the strength properties of Viscose/PET, PET and Twaron fabrics. 32 graphs but nothing new, except the following conclusion seen in print for the first time: “Parallel webs gave higher strength in the MD than cross-laid webs. Moreover, the ratio of MD/CD strength was larger for the fabrics made from the parallel laid webs than from cross-laid webs”

m.acar@lbroro.ac.uk

• PRODUCTION OF SUB-MICRON MELTBLOWN FIBERS FOR FILTRATION PRODUCTS

Gregory F. Ward - Nonwoven Technologies, Inc.

A new melt-blowing head using 9 thou orifices, 0.1 gms/hole/min polymer flow rate and 4 adjacent air jets operating at 5-25psi to produce continuous filaments with a diameter of 0.8 to 0.95 microns. The die is part of their recently patented Spunblown™ system which also features twin orifice rows, ultra-high operating pressure, and, with three double-row beams, an output of 190 kgs/hr at 2.2 metres wide. Estimated cost of the line is $4.5-$5.5million. 25 gsm submicron fabric production has an estimated operating cost of 1.6 cents/sq.metre.

wardpgusa@msn.com

• DEVELOPMENT & MODELING OF MONO- & BI-COMPONENT FIBER MELTBLOWN NONWOVEN PROCESS

Dong Zhang, Ph.D. - The University of Tennessee

PP,PE, PET, Co-PET, PBT, PA-6, PA6,6 polymers were used. Surface response methodology was used to analyse the results. The main conclusion was that the methodology “was an efficient and effective method for melt-blown process optimisation.” They await your call.

csun@utk.edu

METHODS OF MANUFACTURING TO IMPROVE QUALITY OF NONWOVEN ROLL GOODS

Michael Maguire - National Wire Fabric

No text provided

Carol.savage@madisonfilter.com

©CRW Oct 2000.

Polypropylene in Textiles World Congress Huddersfield UK:

Over 260 delegates from 24 countries gathered at the University of Huddersfield to listen to papers presented by 32 speakers from 14 countries. This was the last of a series of conferences organised by Dr Kim Ghandi who retires this year. It was probably the most successful and the series will be a sad loss to the conference circuit. Summaries of the papers grouped according to areas of interest follow:

Increasing Polypropylene Fibres Versatility Through Novel Effect Additives
Jean Roch Pauquet & Patricia Schrijver - Rzymelka, Ciba Specialty Chemicals Inc, Switzerland
Ciba’s new phenol-free stabiliser Fiberstab L112 is based on the HP 136 lactone, the Irgafos 168 phosphite and the hindered amine, Tinuvin 622.
It is as effective as the phenolic/phosphite system during processing but dramatically reduces the potential for gas fading.
The hindered amine component provides the long-term thermal and UV stability compared with a phenolic.
Their latest high molecular weight oligomer hindered amine light stabiliser system, Chimassorb 2020. This gives superior light stability against automotive specifications, high extraction resistance, low volatility and better colour yield (with pigments) than the current state-of-the-art stabilisers.
Their revolutionary new n-alkoxy hindered amine, halogen-free flame-retardant (Flamestab NOR 116) provides protection to PP fibres at unexpectedly low concentrations, while controlling both thermal and light degradation. It can also be mixed with conventional FR compounds such as deca-bromo diphenyl oxide to reduce the concentrations required and improve fibre properties.
Permanent antistatic behaviour can be achieved by blending 4 - 10% of a hydrophilic copolymer into the polypropylene. Irgastat P22 does this by forming a network of conductive polymer chains within the fibre. Surface resistance of the polypropylene is thereby reduced from 1015 ohms to around 1010 ohms at 10% add-on.
Antimicrobial activity can be achieved by adding an additive that has been used in cosmetics for more than 30 years. 0.1% of Irgaguard B1000 allows the fibres to inhibit the growth of gram-positive and gram-negative bacteria.
CIBA were working on an additive to make PP permanently hydrophilic, but did not expect it to be commercial for about 3 years.
None of the compounds were approved for food use yet, but Chimassorb 2020 will be.

Surface Control in Polypropylene Fibres and Fabrics
Dr. Tom W. Theyson, Goulston Technologies Inc, USA
Most topically applied materials had some effect on the strength of any thermal-bond between fibres, the greatest effect arising from silicones. 0.6% of can reduce the thermal bond strength by 55%.
Maybe specialised materials could be developed to enhance bond strengths.
Strike-through times of 2-2.5 seconds were easily achieved with almost any topically applied surfactant, but migration of the chemical into the fluid prevented the achievement of good wicking rates and good multiple-insult strike-through times.
Durable hydrophilicity requires the use of surfactants that can penetrate or be bonded to the fibre surface, and such surfactants must be both oil- (to penetrate the PP) and water-loving.
Goulston has developed such materials that at 0.5% add-on enable PP fibres give 2.5 second strike-through times after 10 wettings: an approach which is now looking capable of being durable enough for textile use.
Other properties achievable from durable topical applications were soft handle, antimicrobial activity from self-polymerising materials and active care properties from baby-oil, aloe etc. In this latter case, only “advertising” levels of activity were possible in fibre production: functional levels of activity needed the materials to be applied on the finished product.
Plasma, sulphur dioxide, fluorine and other high energy surface modification techniques all had potential, especially in conjunction with topical treatments. The first examples of such combinations were just becoming commercially available.

"MOPLEN ULTRA" Innovative Polypropylene Resins Family for Spunbond and Melt-Blown NonwovensGiancarlo Braca, Franco Sartori, Technology Business Support, Montell Europe /Ferrara - Italy
Moplen Ultra 817HOXP is a more stereo-regular polymer with a narrower molecular weight distribution and a higher crystallinity arising from a higher crystallisation temperature and shorter crystallisation time.
When spinning the 25 MFR resin to 0.72 dtex filaments in yarn form, take up speeds of 4500m/min can be achieved compared with 3900m/min for the “benchmark” polymer against which all comparisons were made.
When spun to give the same elongation as the control, the 817HOXP gives a 20% increase in filament tensiles and higher birefringence, confirming the higher level of molecular orientation achieved.
Plant trials on the Lurgi-Docan, the NVT®, and on Reicofil II and III machines all confirmed the laboratory results and showed the 817HOXP to be a very forgiving resin with a wide operating window.
The meltblowing version also has a narrow molecular weight distribution, and a Melt Flow Rate of 1,800 achieved directly in polymerisation and without recourse to peroxide degradation (“Moplen Ultra 810HOXS”).
In the laboratory this can be processed at lower melt temperatures to give meltblown fabrics with finer, more uniform fibre sizes and hence more uniform pore sizes and better barrier properties.
The lower operating temperature should lead to reduced fuming (better working conditions) and lower operating costs.
Industrial scale meltblowing trials are about to take place and the resin is expected to be on the market this autumn.


Hydroentangled - Spunbonded Nonwovens from Polypropylene - High Product Quality for Technical ApplicationDipl-lng. H Erth, Dipl-lng. D Blechschmidt,, Dipl-lng. (FH) M Brodtka, Dipl-lng. (FH) Rainer. Linder Saxon Textile Research Institute, Chemnitz, Germany
Webs of PP from two catalyst systems with filaments from 0.8 to 2 dtex, at 35-300 gsm, made at speeds from 2 to 18 metres/min were first pre-bonded in a calender prior to Fleissner hydroentanglement.
He concluded the metallocene PP gave the best results, and that hydroentanglement generally gave bulkier, softer and more absorbent products than either needled or thermally bonded spunlaid materials.
Surprisingly, nonwoven thickness after hydroentanglement up to 190 bar was always higher, often twice as thick, as the lightly pre-bonded starting webs.
This was the result of fibres being reoriented in the Z-direction.
Asked whether the bulking effect could be achieved on fully-thermally-bonded spunlaids, he said the trials remained to be done.


Production possibilities of Polypropylene Microfibres
Dipl-lng. Christine Harder- Swiss Federal Institute of Tech., Zurich, Switzerland
A review of PP yarn spinning and texturizing processes considering the problems of making pigmented microfibres.
Agglomeration of pigment in the masterbatch was still preventing pigmented microfibres from being commercially attractive.

PP - Fabrics - Your Partner ST
Jurg L Wildhaber- Sulzer Textil Ltd, Switzerland
14%, or 30 billion m2 of World fabric production is now used in the technical textiles sector.
Of this, 32% is “simple” e.g. cotton, fabrics, and 16% is “complicated” e.g. air-bag or aramid fabrics. 14% is glass, and the remaining 38% is based on polypropylene.
Slit-film, multifil and monofil yarns can all be woven on Sulzer projectile looms, typically at widths of 5.4 metres for carpet backing, flexible intermediate bulk containers, geotextiles and agrotextiles.
In the latter category, shades for tobacco plantations were now being woven 6.5 metres wide, and machines to weave up to 8.5 metres wide could now be ordered.
Fibrillated PP tapes could be woven to make geotextiles to outperform nonwovens.


Smart Fibres( Synthetic)
Simon Senior, Drake Extrusion Ltd, UK
A review of the gloomier recent predictions related to population growth and global warming.
He concluded that the pressure on agriculture to feed the world’s population by the year 2050 would leave little scope for growing cotton or trees, or in fact any natural fibres or fibre forming polymers.
Natural fibres would be “squeezed out”, leaving synthetics in general and polypropylene in particular to respond to the textile needs of the expected 11 billion people.
Dreams of smart fibres and textiles would come true:
o T-shirts would have built in Global Positioning Systems so that parents could always know the whereaouts of their children.
o Charged fibres and fabrics would repel dirt into collecting “magnets”.
o Body odour control would be achieved using antimicrobial fibres such as Acordis’ Amicor™ or Drake’s Permafresh™.
o Body temperature would be controlled using phase-change materials.
o Telephone key-pads would be built into shirt-cuffs.
o Strain gauges built into skin-tight undergarments would allow computer analysis of sporting activities (e.g. golf swing).
o Sound systems would be built into carpets (vibrating fibres)
o Over-floor heating systems would be built into carpets.
o Smart rugs would provide therapy for foot ailments.
o Security systems would be built into carpets (footprint recognition).
o Emergency lighting would be built into carpets (fibres that glow in the dark and direct you to an emergency exit)
Drake’s Permafresh™ fibre used a polymer additive enabling 20% of the resulting antimicrobial polypropylene fibre to protect 80% of untreated PP in a blend fabric.
Applications expected in carpet pile and underlay, bedding fabrics, and upholstery, major themes being fungal growth and dust-mite control.


Three interesting Developments which could Boost the image of PP
Francis A Woodruff, Web Processing, UK
Foam coating, in addition its well known advantages, allows the coat to stay on one side even when the fabric has 2mm apertures. The foam collapses in the oven.
Coating growth in the UK is being driven by the Fire Regulations but similarly tight regulations will be adopted by other countries.
Land-fill waste disposal may well be banned: the problems of incineration of latex-backed carpets would increase the emphasis on recycling.
If carpets used PP pile and recycled-PP needlefelt backings fixed to the facing by powder bonding, the whole structure could be melted and recycled to make the needlefelt backing.
Corona and plasma treatments would allow the reactivity of the PP surface to be increased. Reduced pressure plasma treatment was now commercial and atmospheric pressure treatment had been developed.
Wettability and dyeability were improved by these treatments, but the PP film surface energy increase from 33 to 50 dynes/cm2 was still not enough to allow adhesive bonding.
Plasma treatment required banks of electrodes to achieve treatment times of a few seconds.
The improvement in surface activity did decay with time, and any fabric treatment depending on this effect had to be done immediately.
Other successes of plasma treatment trials were:
Increased moisture absorbency of wool.
6-fold increase in peel-bond strength of a polyurethane coating.
Doubling the wet strength of a PET fabric
Quadrupling the wet-strength of a PP/Cellulose nonwoven.
Improved uptake of reactive dyes on cotton.

Quantification of Antioxidants in Polypropylene Using SFE / HPLC
Maria Thilen & Prof. Roshan Shishoo, IFP Research AB, Sweden
Extraction of ground polymer with supercritical fluid followed by HPLC allowed the antioxidant levels in PP to be monitored.
In order to get the best extraction yields, 2% of methanol was added to the liquid carbon dioxide which was pumped at 4 mls/min through the sample at 384 bar and 120oC.
10 minutes extraction was normally adequate but 1 hour used to be absolutely sure.
1 hour of SCFE extraction was shown to be equivalent to 96 hours cyclohexane extraction.
Whatever the method, 70% of the antioxidant was the maximum extractable.
Results from PP thermally aged at 70oC showed that antioxidant level fell sharply after 240 hours.
A knowledge of the antioxidant level in used PP was important in deciding how to recycle.


Asota M40 - A New Generation Polypropylene Hollow Fibre
H Linsbauer - Asota Gmbh, Linz, Austria
The fibre has 3 small holes arranged to create an internal trilobal section, this giving the fibre higher resilience and rigidity than either a single larger hole or the equivalent unenclosed trilobal section.
At 20% blend with wool in carpet yarns dyeing of the PP component is not necessary.
Polypropylene, being higher in the triboelectric series than either nylon or polyester also had a lower tendency to generate static.
Recovery levels from a carpet-pile compression test were quoted as 92.1% from the hollow fibre, 88.5% from the equivalent tri-lobal fibre and 86% from the round section fibre.
Asota also have the technology to add Actigard™ to the polymer to make their fibres antimicrobial.


Polypropylene Industry in Turkey
Dr. Hale Canbaz Karakas, Textile Eng Dept. Istanbul Technical University,Turkey
After China, Turkey is the world’s second largest exporter of IBC’s (big-bags) but is relatively new in PP-containing carpets.
In response to customer demand Turkey plans to develop rapidly to supply PP carpets into the EU.

Electrically Conductive Fibres from Polyaniline-Polypropylene Blends
Prof. P Nousiainen, M Rissanen, A Puolakka, Tampere University of Technology, M Jussila, J Laakso - Panipol Ltd, Porvoo, I Pykko - Tamfibres Ltd, Tampere, Finland
Blends of PP with 10 to 20% of a polyaniline doped with a sulphonic acid could be converted into electro-conductive chips for textile filament manufacture.
Getting the polyaniline to mix properly with the PP was a problem that had been tackled by Neste Oy but the process was secret.
Spinning trials on their compounds showed that the conductive additive had a minor deleterious effect on spinnability. This, coupled with the blend effect, reduced the fibre tenacity by between 14 and 43%.
Extrusion temperatures of 210oC gave uneven blends: 240oC being needed for best results.
In nonwovens, 5% of the PP-PANI fibre in blend with cotton gave improved carding and cross-lapping, and reduced the surface resistivity of the nonwoven from 1011 ohms to 1010 ohms.
In blend with polypropylene the effects were more impressive, surface resistivity falling from around 1012 ohms to nearly 109 ohms at the 5% level of PP-PANI. Increasing the PP-PANI level to 30% did not affect the resistance further.


Dendritic Polymers : A New Concept for Dyeable Polypropylene Fibres
Peter E Froehling, DSM Research, Geleen - Netherlands
Stephen M. Burkinshaw - University of Leeds UK.
Dendritic polymers are “grown” tree-like in 3 dimensions becoming very large, approximately spherical macro-molecules with numerous branches and spaces between the branches that can trap other molecules.
If the ends of the branches are terminated by groups receptive to acid or disperse dyes, the molecules will confer this property to whatever they can be blended with.
4% of a fatty amide polyamine dendrimer allowed acid-dyeable PP fibres to be produced.
At 80oC and somewhat lower pH’s than normal for nylon dyeing, brightly coloured fibres were obtained with a wide range of acid dyes. Unfortunately, the dyes did not penetrate into the middle of the fibre (ring-dyeing) due to their highly polar nature, and wash fastness was poor.
Disperse dyeing PP containing 3% of a fatty amide modified polypropylene-imine dendrimer at 80-120oC gave intensely coloured through-dyed materials with good to excellent wash and rub fastness.
The additives are currently very expensive, dye-baths are slow to exhaust and there are questions over UV stability.
The development continues with, amongst other approaches, attempts to modify the disperse dyes (which have after all been optimised for polyester) to better suit both polypropylene and the dendrimer additives.
CRW Comments: dendrimers terminated with hydoxyl groups should allow the production of permanently hydrophilic fibres, or increase the absorbency of already hydrophilic materials.


Bicomponent PP I PE Matrix Fibril Filament Yarns Spun with the Addition Of Paraffin Oil
Andrej Demsar, Franci Sluga, University of Ljubljana, Faculty of Natural
Science and Engineering, Dept. of Textiles, Snezniska, Slovenia
Polypropylene and polyethylene are largely immiscible in the molten state so the extrusion of a blend of these polymers results in a bicomponency due to fibrils of one polymer being dispersed in a matrix of the other.
Addition of 2% paraffin oil (a plasticiser and compatibiliser) to the extruder generally lowered the viscosity, thereby lowering the dye-head pressure and improving the spinnability.
The resulting yarns were more uniform (reduced C.V. of yarn properties), higher in density with lower spontaneous relaxation, lower in ductility, higher in strength and with a lower melting temperature than those spun without the addition of paraffin oil.

Polypropylene in Staple Fibres with a view to Advanced Process Technologies for One-step Staple fibre ProductionDipl. Ing. Hendrik Tiemeir - Neumag Process Engineering Germany
A comparison of Neumag’s spinning lines for polypropylene.
The low speed inline machine is an economical way of making up to 50 tpd staple.
The compact high speed inline machine makes better fibre up to 10 tpd.


PP Textiles: Into the Future
Colin M. Purvis - Director General EATP, Brussels, Belgium
Worldwide production of PP fibre, slit film, spunlaid and tapes has grown at 6-7% per year on average, is now approaching 5 million tonnes/year and accounts for 26% of the total PP resin usage.
Almost 2 million tonnes is produced in Europe, where it now accounts for 35% of the man-made fibre market.


Market Perspectives of the European Polyolefin Textile Industry
Dr. Jean - Pierre Peckstadt, Senior Adviser EATP, Brussels, Belgium
1.63 million tonnes of resin were used to make textile products, of which 500,000 tonnes were staple fibre and 271,000 tonnes were spunlaid. (1998 figures for Europe)
Medical and hygiene uses accounted for 228,000 tonnes of this (122,000 tonnes being spunlaid/meltblown). Geotextiles used 41,000 tonnes of spunlaid and 15,000 tonnes of staple fibre, 30,000 tonnes of slit film and 20,000 tonnes of mono or multifil yarns.
475,000 tonnes of PP went into floor coverings of which 100,000 tonnes were needlepunched carpet “pile”. (Tufted and woven pile accounted for 145,000 and 125,000 tonnes respectively. The remainder was used for backings.)
The automotive sector is still dominated by polyester, but 20,000 tonnes of virgin PP needlefelt finds its way into car carpets, trunk liners, package trays etc.
Further aggressive growth at the expense of other synthetics is expected as the technology improves and new varieties are developed.


Structure and Properties of Spunbonded Nonwovens Produced from Polypropylene Polymers.
Dr. Gajanan S. Bhat & Rammohan Nanjundappa, The University of Tennessee, Knoxville, USA
TANDEC is working on spunbonds but no interesting conclusions drawn yet.


Polymer Additives for Future Demands and Improvements in Man-Made Fibres
Joachim Bayer - Clariant GmbH, Germany
For melt stability after 5 extrusions (i.e. recycled 4 times), the standard phosphite-based stabilisers were outperformed by a lactone-based multicomponent stabiliser which in turn proved inferior to the two diphosphonite-based stabilisers especially at the lower extrusion temperature (230oC c.f. 270oC).
For colour stability, one of the diphosphonite based compounds (the non-cyclic one) was superior to all other types. This stabiliser also improved the UV stability of a weathered PP geotextile (as measured in the Xenotest 1200).
In further evaluations of accelerated exposure stability against the automotive industry’s hot colour fastness and ageing standards, three different PP types were stabilised with two well-known HALS (hindered amine light stabiliser) compounds.
The number of exposure cycles required to halve the PP’s tensile strength was significantly greater for one of the polymers combined with one of the HALS additives (the Hostavin® N 30).
Polymer and stabiliser choices had to be carefully optimised for best performance against specification.
The Introduction of a New Stabilizing System for Textile Products - Fiberstab L - from the View of a PP ProducerDI. Bernd Schutz - Targor GmbH, Germany
The first grades to use Fibrestab L were commercialised and approved between April 98 and September 99. They now make 4 different PP-grades (Novelin 1101 M,N,R & S) using three different stabiliser systems.
This amounts to 120,000 tonnes/year of filament, staple and nonwoven types.
They are now working on a 6 melt flow rate (MFR) grade for geotextiles using the new stabiliser.
The new stabilizer gave better spinning, better yarn properties, reduced discoloration and good thermal stability.
It also allowed levels of HALS stabiliser to be reduced, and gave the advantages of a phenol-free system to their customers.


The Markets for PP in Textiles Worldwide
G Mackie, Geerdes international Inc, Virginia, USA
European PP textile consumption is only 25% of the worldwide level of 5.7 million tonnes.
Of this 1.35 million tonnes were staple fibre and 750,000 tonnes were spunlaid/meltblown.
Nonwoven uses amounted to 520,000 tonnes in the USA, and 410,000 tonnes in Western Europe.
World resin production of about 23 million tonnes in 1999 could be expected to almost double by 2010.
PP homopolymer resin prices, having fallen to almost $500/ton a couple of years ago, could be expected to rise to $750/ton by 2010.


Spin Finishes for Polypropylene Staple Fibres used in the Spunlace Process

Christine Wild, Cognis Deutschland GmbH, Germany
Compared with viscose or polyester finishes, PP needed more antistatic protection, better lubrication and better wettability, and therefore more finish than the other fibres.
This has to be achieved without creating foam in the HE process and without adding to the filtration load.
The finishes had to be emulsion rather than dispersions and the liquid particle size had to be below 1 micron. They also have to be chemically suitable for hygiene applications and ideally FDA approved.
Stantex S6397: a semi-permanent hydrophilic, low foam finish with improved hard-water stability achieved without the use of complexing agents such as EDTA which might soon be banned on textiles in Germany.
The data presented to support this claim showed the new finish on PP to be superior to a conventionally finished PES fibre in foaming tests with waters of differing hardness, and in sink-time testing.
The new finish was applicable to viscose and polyester also.
Hydroentangled disposable products would continue to be made from viscose for the foreseeable future, but blends with PP, or even PP alone, could be used for more durable products where higher wet strength was needed.
Blends with PP were to be preferred over blends with PES because PP was antimony-free, lower in cost and had a softer handle.


Antimicrobials in Polypropylene - Their Promise and Environmental Impact
Dr. W Curtis White, Robert A.Monticello , James W.Krueger, AEGIS Environments, Michigan, USA, Patrice Vandendaele, Devan Chemicals N V, Renaix- Belgium
Conventional antimicrobials leach from PP fibres to form, in efficacy testing on agar culture plates, a “zone of inhibition” on which the organisms cannot grow.
At the boundary of this ZOI most organisms are killed, but the few that survive are those with enhanced resistance to the biocide.
If cultures are taken of these survivors, and the tests are successively repeated, it has been shown that bacteria can develop complete resistance to the biocide in just three generations.
The Dow-Corning organofunctional silane compounds (as used in medical nonwovens and consumer textiles since 1976) to create an antimicrobial that bonds to PP with excellent durability. (non-leaching)
It’s a 3-trimethoxy silyl propyl dimethyl octadecyl ammonium chloride on a lipophilic aliphatic chain, also known as AEM 5772 or Aegis Microbe Shield.
It bonds to the PP through the silyl group and kills bacteria - without being destroyed itself - by physically penetrating the cell membrane with the aliphatic chain “sword” before “electrocuting” it with the charged nitrogen atom on the quaternary ammonium group.
The compound can be added to the PP spin-finish or padded onto the nonwoven.
It is already in use on Drypers™ diaper topsheets and can safely be used on filters for fish tanks because it is completely non-leaching.
Socks, underwear, bedsheets, waddings and carpets are among the other applications.
On carpets, it destroys the symbiotic fungi on which the dust-mite depends, and so prevents dust-mite colonies from developing.
Its presence on a fabric can be highlighted with bromo-phenol blue indicator.


Availability of Fabrics with PP Fibres for Clothing Purpose
G. Dziworska , Prof I Frydrych., Institute of Textile Architecture, Poland
Comprehensive trials comparing cotton, viscose, polyester, nylon and lyocell with PP in yarns and woven fabrics.


New Technologies for PP - Nonwoven-Production Require Modified Spin Finishes
Dr. Jurgen Peschel - Dr. Alfred Schulberger,- Dr. Th. Bohme K G Chem. Fabrik GmbH & Co. Germany
New spin-finishes for both staple fibre and spun-laid hygienic nonwovens targetting higher production speeds, more efficient processes, and lower production costs while meeting the most stringent dermatological and toxicological requirements of the most demanding consumer products companies such as Procter and Gamble and Kimberly-Clark.
Their Synthesin 7292 is also good on short-cut fibre for air-lay, wet-lay, flock and concrete reinforcement.

Effect of Proportional Blending of Recycled Polyethylene on the Properties of Polypropylene Fibres Intended for Geotextile ApplicationsS. M. Gillon, A. R. Horrocks, M Miraftab, P Davies, Bolton Institute, UK
They took Novolen 1101R polypropylene and added recycled HDPE (injection moulding grade Linpac H-750 recovered from trays and crates).
Virgin HDPE (Rigidex HD 5211) was used as a control.
Up to around 10% of either HDPE was thought to give acceptably small reductions in tensile properties but the recycled HDPE gave poor results in accelerated oven ageing tests.
Work continues to try to find out why this is occurring.


Modelling the Drawing of Polypropylene Fibres : Control Factors and their Interactions
R. Yang , A . F. Fotheringham, R R Mather, & G. Allan, School of Textiles,
Heriot - Watt University, Netherdale, Galashiels, UK
The factorial experimental design used to develop a computer model of PP spinning and drawing was described.
It will ultimately be capable of printing out the process conditions needed to make a fibre with whatever tenacity and elongation is required.
The effects and interactions of spinning temperature, winding speed, metering pump speed and drawing conditions on tenacity, modulus, elongation and crystallinity were presented.
Two-stage drawing emerged as clearly superior to one-stage drawing for all outcomes.


Effect of Resin Properties on the Crystallisation Point of Polypropylene During Spinning
Olivier Merle, TOTALFINA, Fina Research S A, Belgium
Also considered the effect of calendar bonding on the properties of a point-bonded nonwoven fabric.
Thermal bondability, like the tensile properties of a PP fibre, depends crucially on the morphology created during manufacture.
Stress-induced crystallisation, resulting in an epitaxial or “shish-kebab” morphology where lateral crystals form after the main axial crystallisation (which carries most of the load), gives best results.
Cold drawing on the other hand leads to a fibrillar structure that gives nonwovens with lower mechanical properties.
The onset of crystallisation can be determined by observing the spinning filaments with an infra-red camera because crystallisation is an exothermic process.
Molecular weight distribution was found to have the strongest influence on the position of crystallisation, narrower distributions delaying its onset and reducing the bondability of the resulting fibre.
Increases in molecular weight were beneficial to both bondability and fibre tenacity.
Spinning speed has no effect on the crystallisation point.
Nucleating agents have no effect on the crystallisation point.
Fibres are in the nip of a thermal bonding calender for less than 15 milliseconds.
The extreme pressures in the nip increase the melting temperature of the polymer.
The temperature at the centre of the fabric is raised by deformation induced heating as well as conduction.
Sections of bonding points contain fibres that have stayed round, suggesting that melting is not a prerequisite of bonding.


Highly Efficient UV Stabilizers for Polypropylene Fibres
Jerry M. Eng - Cytech lndustries Rotterdam, Netherlands- Leonard H.Davis -Cytec Industries Inc,Stamford, USA, Ivan Vulic -Cytec Industries, Rotterdam, Netherlands
A comparison of the stabilisation performance of four hindered amine light stabilisers for PP.
1)A low molecular weight ester (Tinuvin 770) 2) a high molecular weight polyester (Tinuvin 622) 3) an “optimised” high molecular weight triazine (Cyasorb® UV-3346) and 4) a high molecular weight triazine (Chimassorb 944).
Product 3 from Cytec Industries unsurprisingly proved best in xenon arc weathering tests and Florida weathering.
Meltblown: The Increasing Meltflow Rate and its Benefits
Nancy Noynaert, Borealis Polymers N. V. Beringem, Belgium
Their HL512B (1200 MFR) was recommended.


Innovative Process in BCF Yam Production
Gunter Klambauer, SML, Lenzing, Austria
The new compact spinning plant is flexible and allows fast colour changes.
The texturizer gives very high and uniform crimp contraction over a wide range of deniers.
The resulting yarn gives Texturmat contractions of up to 21% and a thermal shrinkage of less than 0.8%.


Evaluation of Fibre Heatsetting by MDSC
Myriam Vanneste, Valja Everaert - Centexbel - Garren Engineering, Gent Els
Verdonck TA Instruments - Brussels, Belgium
An estimate of heat-setting temperature is traditionally given by the pre-melting endothermic peak (PEP) in a thermogram from a Differential Scanning Calorimeter.
Modulated-temperature differential scanning calorimetry (MDSC) improves on this by splitting the heat flow signal into Reversing and Non-Reversing components with respect to the heat capacity.
Correlation of the onset of NR heat-flow with heat-setting temperature was perfectly linear, and it was concluded that MDSC provided an efficient way of determining the heat-setting conditions for an unknown PP sample.

Nonwoven Network Meeting

PLA Fibres
Jim Lunt of Cargill-Dow Polymers gave the presentation on Poly Lactic Acid fibres. Most of the information had already been published, the following points being worth noting:
- PLA USP: "The only melt-spinnable natural-based fibre."
- CDP think they will need an FTC classification other than Natural, Synthetic or Regenerated. (It’s a synthetic polymer, the monomers for which are obtained from a renewable resource.)
- They are not allowed to claim biodegradation in the USA because the composting infrastructure needed to deal with it does not exist.
- The current 4000 tonnes capacity is being stretched to 8000 tpy ahead of the Blair plant coming on stream.
- They claim to be able to use any carbohydrate and foresee future plants installed in developing countries to use any biomass.


Mr Lunt was wearing a PLA/Wool blend jacket with PLA buttons. PLA golf shirts from Kanebo were passed round along with some knits that looked and felt like microfibre filament polyester.
He admitted PLA (M.Pt. 175oC) could not be ironed successfully: a serious disadvantage in textiles. In mitigation, the fibre, like polyester, was essentially non-iron.
They were developing a 210oC M.Pt version based on a polymer with alternating D and L units - "A stereo complex with interlocking D and L structure." This would be available in 2 years.
PLA does not support bacterial growth and only degraded in composting after hydrolysis at temperatures above 60oC.
Yoghurt pots branded "Danone - Jahreszeit" had been test marketed in Germany: they disappear in 47 days in an composter.
100% PLA teabags are on sale in Japan: from the slide they looked exceptionally uniform. (maybe they were very the woven filament bags used for premium tea-bags.)
PLA has the lowest refractive index of all fibres and hence dyes to very brilliant colours.
With a limiting oxygen index of 26% it is essentially non-flam.
It is unaffected by UV exposure.
Interface, the carpet company were said to have made a great success of PLA in carpets.
He said price would be 50 to 100c/lb with the lower figure being possible but unlikely until cheaper biomass sources become usable - i.e. not from Blair. He confirmed the existence of an exclusive users club with the available fibre rationed between the club members who pay to have access to samples. Blair would be expected to produce 140,000 tonnes of resin and would supply 10 club members each having access to 15,000 tonnes. The paper is on the cdpoly.com website.


Oasis Update
Bill Brunskill of Acordis’s Technical Absorbents (JV with Ciba) reviewed progress with the “Oasis” superabsorbent fibre. The main applications were listed as: cable-wrap yarns, ink-jet pads, Tatami mats, secondary medical dressings, meat and fish tray liners, femcare, cooling bandages and coffin liners.
Products said to contain “Oasis” were circulated for inspection. They included panty-liners with two-part topsheet (a prettily patterned dri-weave target area with soft thermal bond - maybe hydrophobic - at the sides: maybe from P&G).
A detailed comparison with Lanseal (Toyobo) and Fibersorb (Camelot) showed Oasis™ to have the best balance of Free Swell, Retention, AUL, Centrifuge Retention, and Gel Retention results.
Companies mentioned either on slides or on the sample labels were Geca-Tapes for cable wrap, Zorba PLC for meat packs, Dyecor Ltd, and Conveen (inco pads). A written paper was not available.


Wet Laid Specialities
Nigel Walker of Technical Fibre Products reviewed the wet-laid nonwoven niches where they currently have thriving business:
Fibres laid: Ceramic, Zirconia, Microglass, Rockwool, Basalt, Pitch and PAN Carbon, Carbon whiskers, Nickel, Copper, Silicon carbide, Aramids, PVOH.
They produce 500mm to 1700mm widths, 5 to 2000 gsm and down to 5kgs in batch size.
They design and construct their own formers. (Thermal Ceramics Inc. in the USA has one.)
The main applications mentioned were:
battery separators for lithium and silver-zinc batteries.
8 gsm cryogenic tissues free from all organic matter and suitable for use in high vacuum (negligible outgassing at the molecule level)
High temperature insulation (up to 1600oC with alumina papers)
Fire-protection with intumescent papers (Expands 20x - “Thin ‘til Hot”). Fitted to doors, ventilators and pipes, they seal them up in the event of a fire.
Composite manufacture: they make the mouldable sheets for the IBM “Think-Pad” computers, EMI/RFI shielding & “Signature management” mouldings (Stealth)
They recently signed a JV with Johnson-Matthey to make membrane electrode assemblies for the polymer electrolyte fuel cells said to be capable of replacing petrol engines.


Resilient Waddings
Terry Saunders, MD of GTM Georgia USA, sells a system for making high loft waddings by pleating card webs prior to through-air bonding. The resulting fibre orientation is largely Z-direction, the products being 15 to 40mm thick. After bonding, they can be sliced down to as little as 3mm thick. (this seems to be the old Corweb process used to make the superabsorbent cores of the original J&J “Serenity” inco-pad.)
They claim fourteen of their machines are either running or on order. A 3.2 metre line is being constructed in the UK. Eight m/c’s were sold in the USA last year.
The pleater and bonding oven cost $360,000 but a full line would cost $1.3M. The main products seemed to based on waste fibres mixed with 20% bico to allow through-air bonding.
Waddings illustrated were made from textile waste, shoddy, PES, cotton, and waste coverstock. Weights were from 100 to 1600 gsm.
Applications claimed were: Liquid and air filters (very low pressure drop arising from the axial fibre orientation as in a cigarette filter), mattress pads, automotive waddings - insulation, foam replacement, trunk liners - “GM love it”, sleeping bags - “Doesn’t bottom out on compression”.


Tissue Culture
Dr R J Minns, a consultant clinical scientist in the Department of Medical Physics at Dryburn Hospital Durham, has been using textile implants to encourage the growth of new tissue in vivo. Rough hydrophilic, electronegative surfaces appear to be preferred by the fibroblasts responsible for new tissue growth: carbon fibre being better than polyester or PTFE. Hernia reinforcement, pressure sore repair and articular cartilage resurfacing have all been successfully demonstrated using carbon fibre woven/nonwoven composites. He foresees the use of carbon fibre pads to encourage new cartilage growth in joints taking over from hip-replacement operations.


Needle Design
The Foster Needle (George Swarbrick) paper on needle design reviewed the field. Points of interest were:
Needles generally have 9 barbs but in most operations only the bottom 6 ever contact the fibre. 6-barb designs would be shorter, stronger, cheaper and less likely to break. Customers were however resistant to changing from the traditional 9 barb design.
Different designs needed for different fibres. (Glass, Kevlar, Ceramic mentioned).
Rapid growth in felt/clay/woven PP composites for landfill liners. The clay is wetted before needling. Some producers now use 21-barbed needles for these products.
Jute/grass-seed/jute composites were now being needled.
Woven upholstery fabrics are being needled to raise a fuzz on one side to get better adhesion of a subsequent coating.


Landfill Liners
Dave Walmsley of the Environment Agency described the QC procedures required to allow landfill liners to be qualified. Landfill management is a comparatively recent phenomena in the UK, commencing about 15 years ago when problems with leachate began to be understood. If there is no natural clay layer at a prospective land-fill site a liner must be fitted, and this must contain the leachate for very long periods under pressures of some 20-30 tonnes/m2. He expected UK landfilling to be phased out over the next 20 years in favour of recycling, with householders being expected to sort waste into numerous categories prior to collection. Once the recycling infrastructure was in place he saw old landfill’s being mined for reusable waste.


DTI Grants
Dave Groffman of the Department of Trade and Industry listed the numerous grants currently available to small businesses. They included grants as low as £2500 to allow companies with fewer than 10 employees to use consultants to help write the feasibility studies needed to apply for larger grants!


Recycled PET Spunbonds
Mechanniche Moderna’s paper on spunbonds from recycled PET was in fact an advertisement for their entire PET spinning machine range. Recycled PET has to be dried to below 30ppm water to avoid degradation. Intrinsic viscosity of the resin falls by 0.01% for every 16ppm water. (The written paper was a collection of slides on an apparently unrelated subject.)

CRW