1999 - volume 2 - jeff. journal of engineered fibers and fabrics

International Nonwovens Journal Home PageVolume 8 No. 2 Fall, 1999
Air Filters For Ventilating Systems — Laboratory and
In Situ Testing
Table of Contents
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Guest Editorial Director's Corner Emerging Technology Rsearcher's Toolbox Standards Development Forum Patent Review
Association Focus; TAPPI The Nonwoven Web Pira Worldwide Abstracts Association News Nonwovens Calendar
PAPERS Air Filters For Ventilating Systems - Laboratory and In Situ Testing Original Paper by Jan Gustavsson, Camfi
Evaluation of the Filtration Performance of Biocide Loaded Filter Media Original Paper by Wayne T. Davis, B. Alan Phillips, Maureen Dever, Thomas Montie and Kimberly Kelly-Wintenberg, The University of Tennessee; and Sarah Macnaughton, Microbial Insights, Inc
Characterization of Melt Blown Web Properties Using Air Flow Technique Original Paper by Peter Ping-yi Tsai, TANDEC, The University of Tennessee
Foamed Latex Bonding of Spunlace Fabrics To Improve Physical Properties Original Paper by A. Shahani, Bell Atlantic; D.A. Shiffler and S.K. Batra, Nonwovens Cooperative Research Center, North Carolina State University
Fiberglass Surface And Its Electrokinetic Properties Original Paper by Daojie Dong, Owens Corning
Applications Of On-Line Monitoring of Dynamic Forces Experienced By Needles During Formation Of Needled Fabrics Original Paper by Abdelfattah M. Seyam, Nonwovens Cooperative Research Center, North Carolina State University
Development of Thermal Insulation For Textile Wet Processing Machinery Using Needlepunched Nonwoven Fabrics Original Paper by Randeep S. Grewal, Flynt Fabrics; and Dr. Pamela Banks-Lee, North Carolina State University
Comparison Of Trends In Latex Emulsions For Nonwovens and Textiles: China and the United States Original Paper by Pamela Wiaczek, Kline & Company
Fiber Renaissance For The Next Millennium Author's Perspective by Arun Pal Aneja, DuPont
Publisher Ted Wirtz President INDA, Association of the Nonwoven Fabrics Industry
International Nonwovens Journal Home Page
Teruo Yoshimura Secretary General ANIC, Asia Nonwoven Fabrics Industry Conference
Editors Rob Johnson 609-256-1040 [email protected]
D.K. Smith 602-924-0813 [email protected]
D.K. Parikh TAPPI
Teruo Yoshimura ANIC
Production Editor Michael Jacobsen Jacor Publications, Inc. 201-612-6601 [email protected]
Cover Photo provided by AQF Technologies, Charlotte N.C.
The International Nonwovens Journal is published by INDA, Association of the Nonwoven Fabrics Industry, P.O. Box 1288, Cary, NC 27512; www.inda.org. Copyright 1999 INDA, Association of the Nonwoven Fabrics Industry. No part of
this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, or by any information storage or retrieval system, except as may be expressly permitted in
writing by the copyright owner. The magazine is sent free-of-charge to all members of INDA and TAPPI, P.O. Box 105113, Atlanta, GA 30348; 404-209-727; Fax 404-446-6947; and ANNA (Asia Nonwoven Fabrics Industry Conference),
Soto kanda 6-Chome Bldg. 3Fl, 2-9, Chiyoda-ku, Tokyo, 101, Japan. The International Nonwovens Journal can not be reprinted without permission from INDA. INDA¨ is a registered trademark of INDA, Association of the Nonwoven
Fabrics Industry
To the Future By Behnam Pourdeyhimi Ph.D., CText ATI, FTI; Professor, and Co-Director, Nonwovens Cooperative Research Center, North Carolina State University, College of Textiles
I had the opportunity to attend both INDEX '99 and ITMA '99 earlier this year. At both, I listened to
messages about continued growth of the nonwovens industry, and future prospects for the industry in the global economy. At these meetings, I met with companies involved in various segments of the industry, including raw material suppliers, roll goods producers, converters and fabricators of the end use products, and machinery manufacturers.
What was perhaps the most interesting aspect of my visits was the fact that most of the processes and products on display did not exist two or three decades ago; those that did are now referred to as "aging" technologies. This is not surprising given the new developments exhibited at INDEX and ITMA, although even the "aging" processes have also been improved significantly over the same time period. I came back from these meeting with the feeling that nonwovens will continue to play a significant role in the polymer-fiber-textile enterprise for many years to come.
EDITORIAL ADVISORY BOARD Chuck Allen INDA Roy Broughton Auburn University Robin Dent Albany International Ed Engle Fibervisions Tushar Ghosh North Carolina State Bhuvenesh Goswami
Clemson University
Fiberglass Frank Harris HDK Industries Albert Hoyle Hoyle Associates
In the near future ANNA/ANIC will be providing members to the Editorial Advisory Board from their geographic region.
It has been estimated that this industry contributes more than $30 billion to the U.S. economy, and will continue to grow at a rate of at least 5-6% annually. This is indeed great news for the industry!
As a professor and educator, however, I have to wonder about the availability of the trained human capital required to help sustain this industry. Presently, the nonwovens industry primarily undertakes in-house training of individuals with degrees in engineering or science. This has undoubtedly contributed to the innovations in the field; however, I am not certain if this can continue to be a viable option given the
Editor's Corner
Marshall Hutten
Hollingsworth & Vose
Nemours Joginder Malik Nelson Industries Alan Meierhoefer
Dexter Nonwovens
Michele Mlynar
Georgia Tech
Univ. of Oklahoma
Univ. of Tennessee
In the near future ANNA/ANIC will be providing members to the Editorial Advisory Board from their geographic region.
complexities of the materials, processes and products available today.
Gaining, and indeed maintaining, leadership in this emerging field requires substantial investment in human capital as well as inventing fundamentally new mechanisms for achieving "versatile" processing; i.e., processing of large volume and specialized materials with a substantially common production domain AND environmental compatibility.
In order to maintain the present level of innovation, it is necessary to develop a more structured model for training our future nonwoven specialists. In academic institutions, our efforts in this regard should be focused on training these "new" personnel with sufficient breadth and depth in the variety of disciplines that impact the nonwovens industry. This multidisciplinary education will well prepare them for a role with the new, versatile and sustainable technologies that will require a fundamental, adaptable knowledge of process synthesis, integration and subsequent transfer to industrial production. It is clear that industry and academia need to engage in open debate on the important matter of to how to prepare for the future.
Ed. Note: Dr. Pourdeyhimi has recently joined the faculty at NCSU as Co-Director of the NCRC. Dr. Pourdeyhimi was most recently on the faculty at Georgia Tech and authored an article in the SPRING, 1999 issue of INJ.
— INJ
Return to International Nonwovens Journal Home Page & Table of Contents
Editor's Corner
THE DIRECTOR’S CORNER A few years ago there was considerable concern about the possibility of electromagnetic radiation fields causing human cancers. The primary concern focused on high power transmission cables that frequently traverse residential areas. Many people were concerned that living under or around high powered transmission lines was injurious to health, particularly the health of children.
As a result, there was considerable government-sponsored research to determine the reality of this concern and to quantify the risks involved. One particular study provided considerable fuel for this controversy and resulted in numerous expensive actions taken as a precautionary measure.
The study was produced by a scientist named Richard Liburdy; in it, he stated that he had proved a link between high voltage lines and cellular changes in the body that could lead to cancer. This resulted in an acceleration of research devoted to the topic, despite the fact that many other studies, particularly those emanating from Europe indicating that no relationship existed.
NON-COMPLIANCE CORRELATION EPA Act Non-Compliance Events CAA — Clean Air Act 0% CERCLA — Comprehensive Environmental Response, Compensation and Liability Act (Superfund)
9%
CWA — Clean Water Act 29% EPCRA — Emergency Planning and Community Right-to-Know Act
7%
RCRA — Resource Conservation & Recovery Act 23% TSCA — Toxic Substances Control Act 12%
Shortly after the study received wide circulation, a whistleblower told the Federal Government, which had funded this particular research, that Liburdy had manipulated his data. The Office of Research Integrity, a bureau within the U.S. Department of Health and Human Services that monitors many federally funded research projects investigated. Further examination revealed that Liburdy had discarded data in preparing a graph for his publication which did not fall on the line purporting to support the hypothesis. In fact, further examination revealed that Liburdy had used only 7% of the data generated during his studies. As a result, Liburdy requested of the scientific journals that had published his work that three key
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paragraphs be rescinded. Despite this action Liburdy claimed that he had done nothing wrong. However, he did leave the Department of Energy’s Lawrence Berkeley National Laboratory, where he was employed, and he has lost a portion of the $3.3 million grant from The National Institutes of Health, Department of Energy and Department of Defense.
During and since these investigations, other studies have been published, all of which confirm the fact that there is no link between the electromagnetic radiation field and living organisms. Unfortunately, Mr. Liburdy’s deception kept the unfortunate myth alive for a period of time and fostered many actions of "prudent avoidance;" the latter term has been concocted to mean that if there is even a hint of health problem, play it safe and avoid exposure. As a recent article in the Wall Street Journal points out (Wall Street Journal, July 27, 1999) prudent avoidance "constitutes a rejection of science and a triumph of fear over reason" and, as physicist David Hafemeister of California Polytechnics State University notes, "prudent avoidance is a delight for plaintiff lawyers since it is essentially a conclusion that the danger is probable."
In this case prudent avoidance resulted in massive expenditures in many different areas and conditions.
Unfortunately, researchers seeking additional government funds know that research results which promote the concept that a growing problem exists can help assure a continuation of grants. This has resulted in what some critics have called "regulatory science." Unfortunately, the Liburdy episode has not done much to discourage this viewpoint. Although the falsification of data by Mr. Liburdy was exposed in 1995 he remained on the job until this past May. His "punishment" for his unscientific behavior consisted of an agreement that he would not apply for more Federal grants for a period of three years.
Science in the Courtroom In recent years there has been considerable concern about the impact of science in litigation and in the courtroom environment. Unfortunately, many examples exist where testimony offered in court cases have been labeled as "science," but has failed to meet the standards normally expected of a scientific discipline. In some cases, the deviation from scientific principles has been appalling.
As Supreme Court Justice Stephen Breyer wrote in an opinion last year: "Society is becoming more dependent for its well being on scientifically complex technology, so, to an increasing degree, this technology underlies legal issues of importance to all of us." Because of this increasing importance of science in the courtroom, attention has been focused on ways to insure that only the highest standards are employed in such contributions.
The Supreme Court of the U.S. has made it very clear that the judges themselves are responsible for the accuracy and reliability of scientific evidence presented in their courtrooms. There have been several recent cases adjudicated by The Supreme Court that has stressed the absolute necessity to keep junk science out of technical testimony.
While there can be widespread agreement on the objective, the means to accomplishing this goal can be difficult delineate.
Some judges have enlisted the use of independent experts. The judge in the silicone breast implant case, for example, appointed a four-member panel of independent experts to help him sort through the science.
An encouraging approach to develop a system that insures the highest scientific standards in the
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courtroom has been made by the American Association for the Advancement of Science (AAAS). This organization has been working with a group from the American Bar Association to study the problem of scientific evidence in the courtroom. Representatives from these two groups have been meeting for the past few years as the National Conference of Lawyers and Scientists. In the past few months, the AAAS has started a five-year demonstration project in which independent scientists with the appropriate expertise can be identified for judges to consider as scientific resources in determining the truth in litigation.
Although the mechanism has not been completed, the project is making progress, including establishing and experimenting with the process by which experts are selected. Several subsidiary bodies chosen by AAAS staff and the advisory committee will attempt to develop procedures for both identifying and recruiting such experts.
Another committee within the national conference is attempting to develop guidelines to screen experts for potential conflicts of interest. The use of anonymity in describing potential experts will likely be helpful in the selection process.
Other groups within the conference are working on the methods to make expert lists available and to alert the judges of the appropriate procedures in utilizing such services. Another activity is directed toward educating the scientists as to the intricacies of the legal process.
While the initial efforts are being focused on Federal courts, it likely the project can be extended to State courts if the procedure proves successful. This is most desirable, as the State courts are the venue of most tort litigation and especially the most outrageous tort litigation.
Hopefully these efforts can prove successful and the "legal lottery" can be eliminated along with the presence of junk science in the courtroom.
The Value of People It has often been said that a company’s most valuable single asset is the people they have. The same can be said of the academic environment; quality of the researchers controls the quality of the research.
Finding, hiring and keeping good people is a never-ending task for the research administrator, whether in industry, academe, or elsewhere.
One of the tools in identifying the best candidates for the job is embodied in a variety of pre-employment assessments. These are generally tests that usually consist of questions relating to the skills, behaviors and attitudes that are necessary for a particular job and a particular environment. These tests can take many different forms. The idea behind the test is to identify those applicants with the best chance of becoming productive scientists and contributors to the industrial or academic research effort.
The desirability of picking the right employee is also coupled with the importance of retaining the employee. The average length of employment of an individual at any professional job in the United States has been declining in recent years and is estimated to be somewhere between two and four years by some human resources specialists.
Along with the need to retain good researchers is the growing recognition that everyone needs balance in their lives. There must be meaning and satisfactions in their work, but this needs to be balanced with their personal, family and private aspirations. A recent review of this situation by one human resources
Directors Corner
specialist, Roger E. Herman, gives five reasons why people leave employment and what to do about the situations. His list of five reasons for departure include the following:
"It doesn't feel right around here."
"They wouldn't miss me if I were gone."
"I don’t get the support I need to get the job done."
"There’s a new opportunity for growth somewhere else."
"I’m not being adequately compensated."
Herman stresses the essential point that each individual needs to feel valued in his/her situation. It is important to clearly exhibit to the employee how their effort fits in with the overall activity and how it contributes to the success of an organization. It has been found that compensation is not the motivator it once was. However, it is still important to have a competitive benefits package.
Of equal importance are the subtle "perks" that say "I am valued." There is a need for public recognition, and the research director that is innovative in selecting the method of such recognition is making a wise investment.
Incidentally, a book entitled "1001 Ways To Reward Employees" (Workman Publishing Co. Inc; New York, NY) has been selling very well. Its author, Bob Nelson (Nelson Motivation, Inc.; P.O. Box 500872, San Diego, CA 92150; 619-673-0690; Fax: 619-673-9031; www.nelson-motivation.com) has written several books on management and business skills, and is a very popular speaker.
Protecting The Environment and Your Staff Environmental protection, along with employee safety and health, are research director's concerns that seldom actually benefit the bottom line. These responsibilities are viewed by many in the same way that a lot of plant managers view filtration: "Filtering our product doesn’t add any value, it simply adds cost." However, this attitude relates to an old adage that says: "Do it right the first time and you won’t have to do it the second time."
It is true that the industrial or academic or research director spends more time, effort and research resources on these two factors than the research director of a couple generations ago. Every old timer can relate stories of how a critical plant run was made late at night with a "jury rig setup, taking more than a few risks." However, those times are gone and will never return. Today’s reality is that the research administrator has responsibility for occupational health and safety of the group, along with an environmentally sound operation.
In terms of industrial plant sites, considerable pressure has been applied by the Environmental Defense Fund (EDF) and the Federal Government’s EPA (Environmental Protection Agency). A few months ago, these two organizations jointly launched an internet web site designed to pinpoint environmental problems. No plant manager, or research director for that matter, would like their operation's mistakes, hazards, accidents and just unfortunate incidents broadcast to the entire world. However, this web site lists plant and location emission problems by their Zip Code, making it relatively easy for anyone to check into the performance of their neighbor. It is a little bit like having the contents of your closet exposed, skeletons and all.
While many industrial concerns initially expressed dismay at the thought of such exposure, the result has been surprisingly different. This site has not been a pandora's box of problems and a source of major
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Rather interestingly, some trade associations for the chemical, petroleum and other manufacturing industries have adopted the information site technique to inform and educate their neighbors as to their problems and their remedial efforts.
As an example, the Chemical Manufacturers Association (CMA) is launching a web site called "Chemical Guide." This will be an information site to the plant, the community, the employees and the surrounding neighbors. The CMA has developed templates that member companies can use to report information ranging from environment, health, and safety statistics to financial information, and even job postings. As a CMA spokesman has indicated, "It’s not an attempt to change the public’s perception of the industry; it’s meant to personalize our facilities."
In a similar vane, many organizations have "gone public" with respect to injury and illness reports. An example is a new web site that provides online versions of environmental, health and safety reports; it is being offered by 111 companies in the U.S. (www.ehsreports.com). This type of internet site was rather strongly tilted to environmental reports when initiated; now, many companies are trying to strike a better balance in providing health and safety information.
Laboratory tours, plant visits and similar activities where appropriate, can go a long ways to building positive relationships with neighbors, employee families and other interested parties. Such activities can also help to boost the esteem of employees and staff members. In a time of electronic information, it is often more prudent to exploit than to resist.
Employee Safety Initiatives In line with the research director’s concern with employee safety, a frequently asked question is: "What legal rights do employees have to take actions to see that their employer complies with OSHA Standards?"
This is an interesting and rather important question for research directors, plant managers and administrators in general. A rather definitive answer to this question was recently provided by Daryl Brown of J.J. Keller & Associates ([email protected]). Mr. Brown indicated that The Occupational Safety and Health Act of 1970 created by OSHA within the Department of Labor was inaugurated to encouraged employers and employees to reduce workplace hazards and to implement safety and health programs. This law gives employees many rights and responsibilities, including the rights to do the following:
• Review copies of appropriate standards, rules, regulations and requirements that the employer should have available at the workplace.
• Request information from the employer on safety and health hazards in the workplace, precautions that have been taken and procedures that should be followed if the employee is involved in an accident or is exposed to toxic or hazardous materials.
• Have access to the employee’s exposure to harmful materials, and medical records that are relevant to the situation.
• Request the OSHA area director to conduct an inspection if they believe that hazardous conditions or
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• Have an authorized employee representative accompany the OSHA compliance officer during any inspection tour.
• The right to respond to questions from the OSHA compliance office, particularly if there is no authorized employee representative accompanying the compliance officer doing the inspection tour.
• The right to observe any monitoring or measuring of hazardous materials and to examine the resulting records.
• Have an authorized representative or the employee themselves review the OSHA 200 Log at a reasonable time and in a reasonable manner.
• Object to the abatement period set by OSHA for correcting any violation in a citation issued to the employer; this is done by writing to the OSHA area director within 15 working days from the date the employer receives the citation.
• The right to be notified by the employer if the employer applies for a variance from a OSHA standard; also, the right to testify at the variance hearing and to appeal the final decision.
• The employee has the right to have their name withheld from their employer upon their request to OSHA, if a written and signed complaint is filed.
• The right to file a discrimination complaint if the employee is punished for exercising any of the above rights or for refusing to work when faced with an imminent danger of death or serious injury and there is insufficient time for OSHA to inspect the situation.
While this listing of the employee rights is rather lengthy, a consideration of each item rather clearly establishes the appropriateness of each of these rights.
Violations of Environmental Laws Anyone who has been involved in a laboratory or plant inspection by EPA (Environmental Protection Agency) inspectors knows how stressful this situation can be. In many cases, honest efforts have been made to do an effective job and to abide by EPA Regulations. The sheer volume and complexity of such regulations, however, often leaves the whole operation on a rather "chancy" basis.
In a rather unusual exercise, the EPA and the Chemical Manufacturers Association (CMA) recently collaborated on an effort to determine why companies fail to comply with environmental regulations. The CMA was very willing to participate, as explained by their legal counsel, because "historically the EPA had been addressing only the symptoms of violations, and here was the opportunity to find out what the causes are."
The three-year project was carried out as "Root Cause Analysis Pilot Project." EPA prepared the survey and sent it to 50 member companies who had encountered problems with violations between 1990 and 1995. These violations were non-criminal, but represented a breach of the regulations, nevertheless.
The report on the results of the survey (http://www.epa.gov/oeca/ccsmd/rootcause.html) detail six primary root causes for facility violations. These causes were as follows:
1. Facility unaware of the applicability of specific regulation.
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2. Human error in judgment or responsibility. 3. Failure to follow EPA procedures. 4. Faulty equipment design or installation. 5. Problems with compliance by contractors. 6. Various communication difficulties.
From this study, it was determined that certain kinds of compliance problems are most regularly associated with particular laws. Specifically, it was found that the laws relating to two federal acts have more than one- half the violations involved, primarily because the laws were confusing and ambiguous. These two items were EPCRA (Emergency Planning and Community Right-to-Know Act) and RCRA (Resource Conservation & Recovery Act). On the other hand, the problems with the Clean Air Act (CAA) did not involve misunderstandings or permit violations. The violations that did occur regarding the CAA all involved operational and procedure-related problems, such as equipment failure and similar.
The report results are summarized in the chart at the top of this page.
Again, under the Clean Water Act, most of the problems with faulty water discharges had their basis in the equipment installation or design.
Also, it developed that companies which have environmental audit programs and corporate policies, goals and targets for regulatory compliance were the best performers as to compliance. These companies also reported that when violations were found, their emergency management systems were usually changed to avoid recurrence of the problems.
From this study, a number of recommendations for both EPA and industry were provided. For EPA, it was suggested that the agency articulate its regulations more clearly and provide immediate compliance assistance and "plain-English" guides for every new rule. Also, it was suggested that EPA could work more closely with state and environmental agencies to insure that regulations are interpreted consistently.
On the part of industry, it was suggested that more effort should be devoted to the development of comprehensive environmental management systems and the promotion of a increased level of awareness of such systems amongst all employees. Accurate, standardized operating procedures and improved employee training were also recommended.
—INJ
Directors Corner
INJ DEPARTMENTS
EMERGING TECHNOLOGY WATCH Sunlight Barrier Fabrics Because of publicity, there is a heightened awareness of the dangers of skin cancer due to exposure to the sun's rays. The risk is not insignificant, as more than a million cases of skin cancer are diagnosed in the United States each year, according to the American Academy of Dermatology. About 45,000 of these cases will be the deadly strain of skin cancer called melanoma, where the cancerous growth penetrates the skin layers into the underlying tissue. Melanoma kills over 7,000 people a year in the U.S.
Responding to this hazard, there has been considerable interest in the use of clothing to protect against the deleterious effects of the sun's rays. Clothing, of course, does not eliminate the need for sun block creams and lotions on exposed areas of skin. However, for most of the body surface, adequate clothing can provide a very effective sun block.
The problem is that in the summertime adequate clothing may be discarded in preference for very light, open fabrics that are more cool, comfortable and stylish. As a result, there has been considerable interest in recent years in developing fabrics specifically designed to block the sun and yet provide comfort and aesthetics that are normally associated with summertime clothing.
If a fabric is heavy enough, it can effectively block the sun's rays. However, there has been considerable effort to develop fabric finishes for lightweight fabrics that can still provide adequate protection and yet be lightweight, open, breathable and stylish.
This has resulted in a rather sudden growth in fabrics and clothing exhibiting good blockage of sunlight and thereby give strong protection against the problems associated with sunlight and human skin.
Unfortunately, no standardized techniques have been developed in the United States for measuring how well a fabric blocks sunlight. Australia does have a standard method that applies to new, dry materials. There are efforts underway in the United States to establish a voluntary standard.
In the meantime, companies that promote special fabrics as a solution to the problem are utilizing a variety of methods to measure the effectiveness. Clothing that is wet or that has been washed repeatedly
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can have a very different ability for blocking the harmful effects of the sun.
Some apparel companies have focused on this market niche and offer a variety of clothing claimed to provide considerable protection. Such apparel generally is quite expensive, however, and the consumer is left to gauge whether the additional expense is worth the claimed protection.
At least one company in Israel has developed a finish technology which it claims provides the perfect solution to UV protection. As can be expected, the major focus of this effort has been on fashionable apparel fabrics, but there are indications that this technology will be extended to nonwoven structures as well.
The process developed by Golden Guard Technologies Limited apparently involves the formation of a strong, flexible, breathable and translucent polyurethane finish that incorporates UV absorbers and attenuators. It is claimed that fabrics that transmit nearly 50% of the UV light before treatment, show a transmission of only 2-4% after treatment. The claims also indicate the finish results in a minimal impact on the moisture-vapor transmission rate and on the fabric hand and drape. This protection is unaffected by moisture, perspiration and machine washing, and is durable to abrasion, along with wear and tear, according to the developers (Golden Guard Technologies Ltd, 21 Havaad Haleumi Street, P.O. Box 16120, Jerusalem 91160, Israel; 972-2-675-1123; Fax: 972-2-675-1195;. www.sunprecautions.com and www.sunprotection.com.
Reactive Protective Clothing The category of "protective clothing" covers a broad range of hazards. As discussed in the item above, even sunlight can be a focus, and an appropriate one, for protective clothing. Anyone who has dealt with a baby diaper knows that it is also a form of protective clothing.
More specialized hazards are being considered, however, and some innovative research is being devoted to such hazards.
A recent development shows a rather dramatic approach to a specific situation, that of clothing worn by agricultural workers, specifically those workers exposed to a significant amount of pesticides. In many such cases the pesticide can pass through the clothing to the skin of the worker and there constituted a significant hazard.
The solution worked out by researchers at the University of California-Davis involved clothing treated with chemicals to detoxify such pesticides. These investigators treated cotton fabric used to make shirts with a cyclic hydantoin compound, which grafted onto the cellulose backbone of the cotton fiber. The fabric is then treated with a bleaching process similar to that normally used in washing clothing.
This process, using sodium hypochlorite solution, converts the hydantoin moiety into a halamine group. Interaction of the halamine group on the surface of the shirt fabric with carbamate-type insecticides results in the carbamate breaking down into small, harmless fragments. In the process, the halamine is converted back into the hydantoin. Washing the clothing, with a bleach treatment, then regenerates the halamine, ready to provide the protection.
Thus, the garment is able to go through a cycle: (1) providing protection, (2) washing and bleaching, (3) regeneration of active site, ready to again provide the protection.
Emerging Technology
R - N - H ...............> R - N - Cl <............... Detoxification
This concept of a reactive fabric undoubtedly has many other potential applications. In a sense, fabrics with some types of flame retardant treatment or fabrics with an antibacterial finish function as reactive fabrics in the appropriate environment.
Innovative thinking should yield other functional groups and situations where the utility of a nonwoven fabric can be enhanced by its ability to undergo selective reaction in a pre-determined environment.
Environmental Technology Forecast As indicated by the item above, nonwoven products have played a very prominent role in environmental protection and remediation. This has involved meltblown technology, needlepunch technology, spunbond technology and others.
With innovation and ingenuity on the part of nonwoven technologists, nonwovens can play an increasingly vital role in dealing with our environment.
To that end, it is well to look at the future of environmental technology, seeking opportunities for contributions from the industry's technology. Consequently, the 10 top environmental technological breakthroughs anticipated in the next decade are worthy of study and consideration.
These breakthroughs have been predicted by researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory. While forecasts of the future are always difficult, and the prediction of breakthrough events is especially difficult, the list is worthy of study. Their 10 top breakthroughs are as follows:
Agrogenetics ... This involves genetic engineering and plant manipulation, which is expected to reduce agricultural impacts on the environment. Growing crops will require fewer amounts of pesticides due to greater pest resistance and some crops will be engineered to require less fertilizer and water while yielding higher yields. This is an area where agrotextiles will have an impact.
Smart Water Treatment ... Improvement in the water treatment at sewage plants, municipal water supply systems will likely result in automatic adjustments to unplug themselves. Sponge-like grains of sand will attract and hold nitrates and heavy metals to protect drinking water. Such smart membranes and filters can have a powerful impact on environmental protection in the future.
Renewable Energy Storage ... By means of improved power storage systems, the use of electricity generated by solar and wind power will show an increase. Renewable energy sources will help slow increases in greenhouse gases by replacing carbon-based fuels. The improvement in electric storage batteries will also increase the utility of such items in transportation and other uses.
Microtechnology ... It is suggested that room air will be heated and cooled more efficiently by tiny channels of micro-heat pumps, thus saving considerable energy. Microchemical plants will produce industrial chemicals as needed, eliminating storage and transportation safety issues.
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Paperless Society ... The use of wireless communications, innovative displays and individualized web publications will help reduce the reliance on paper for many activities. Advanced display systems may imitate paper in flexibility and portability. The researchers suggest that one approach will involve projecting images directly on the retina of the eye. This capability, coupled with a cellular phone, could provide faxes and customized news anywhere. For paper products that continue to be used, biodegradable inks will be more common.
Molecular Design ... The use of molecular design for catalysts can make chemical reactions and processes so precise that little or no wastes are produced. It suggests that sensors designed at the molecular level will monitor material and chemical manufacturing processes more precisely. This will help to halt or correct processes that are sensitive to temperature changes and other parameters. This breakthrough may expand uses of nonwovens, but may also have an impact on the production of nonwoven products.
Bioprocessing ... This concept utilizes microorganisms and plants that will "grow" environmentally friendly chemicals and biological products. Included among these materials may be drugs, proteins and enzymes for many uses. Producing chemical feedstocks, fuels and pharmaceuticals in this manner will be cost effective and better for the environment. The researchers suggest that microorganisms retrieve from extremely hot, cold or forbidding environments (extremozymes, such as are recovered at hot holes in the ocean floor) may expand the range of temperatures and conditions used in manufacturing biotechnical products. This may create opportunities for new, environmentally friendly bioprocesses while saving time and energy.
Real-time Environmental Sensors ... By the use of yet-to-be-developed sensors, supermarkets could detect the presence of bacteria and other dangerous pathogens in food. Workplace air quality could be monitored to prevent "sick building syndrome." Other benefits that may result from monitoring in the environment include control of airplane and other transportation environments, preventing infections in hospitals and in municipal water supplies and in guarding against pathogens potentially used in biological terrorism.
Enviro-manufacturing and Recycling ... Greatly enhanced recyclability of a whole range of products may change the complexion of entire environmental protection in the future. Increased use of biodegradable material in such things as plastics, paper, cars and computers will have an impact. Dry cleaning with liquid carbon dioxide will minimize or eliminate this source of environmental pollution. Recycling will become "second nature" to all of the citizens of the world, and recyclates will be a major resource for future civilizations.
Lightweight Cars ... As the weight of automobiles is reduced by the use of advanced materials, the family sedan will get at least 80 miles per gallon of gas, generate less pollution and use more recycled materials. Lighter weight cars will be built with less steel and more lightweight aluminum, magnesium, titanium and composites. Advanced metal forming techniques will provide precisely the strength needed at every point. The 150 pounds of glass used in today's cars will be cut by a third or more by the use of a composite sandwich of glass and plastic. Today's 100-pound air conditioners will weigh half as much, particularly as glass is specially coated to reflect or absorb heat radiation.
While some of these concepts may sound far fetched, many of them already have a running start in parent technology. Further details on the environmental technology forecast coming from the U.S. Department of Energy can be obtained: Greg Koller at Pacific Northwest National Laboratory;
Emerging Technology
greg.koller@p&l.gov; 509-372-4864; http://www.pml.bill/news/back/envirbg.htm.
Emerging Technology
INJ DEPARTMENTS
RESEARCHERS TOOLBOX
Good ideas are always welcomed by the effective researcher. Good ideas can help get a difficult job done easily. Sometimes the right method or tool can get results that would be difficult to do any other way. Occasionally, the right idea provides a result that simply could not be accomplished otherwise. Hence, a new trick to put into the collection of tricks is always a worthwhile addition. If you have such an item to share, please let us know so we can include it in a future offering.
Here's hoping that one of the current collection will prove useful.
Temperature Indicators In dealing with thermal processes it is sometimes vital to know the maximum temperature reached by a fabric or system. It would be very convenient to be able to insert something that would register the maximum temperature, or would give a signal if a certain temperature is achieved.
A quick, inexpensive and easy solution to this need can often be obtained with the use of temperature monitor product. These can be paper or film label products having a window or small panel that changes color upon being exposed to a set temperature. Often a label or tape product will carry a series of four-to-eight spots that correspond to a specific temperature. When the product is exposed to that temperature, the spot changes from a light color to black or some such dark color, so there can be no doubt that the temperature was experienced.
Self-adhesive temperature monitoring labels can be attached to a web undergoing thermal treatment, giving a positive indication that a certain temperature was achieved within the web. Such monitoring labels can have spots indicating a temperature of 100F between each rating. Other styles have temperature differentials of 250 or 500 F between spots. The spots or indicator panels can have a variety of shapes and configurations, including circles, micro-dots, buttons, bars, and forms of bull's eye, clock and thermometer configurations.
In general, the temperature range of 1000 to 5000 F is available, and an accuracy of 1% is guaranteed. Such temperature monitoring systems can also be provided in a pencil or stick version, which allows a mark to be made on a surface which then changes as that specific temperature is achieved. Also, the products are provided in paint form so that a cover or machine housing can be converted into a temperature-indicating probe.
The monitoring tape product is often used with fusing ovens or fusing presses, to confirm the fact that a temperature adequate for a fabric bonding step has been achieved. This can be done by placing the indicator on a belt traversing the oven, or between layers of fabrics or sheets. This has been particularly useful in
Researchers Toolbox
applications involving the bonding of nonwoven fusible interlinings and interfacings to outer face fabrics.
A well-established source for such products is Tempil, Inc. (2901 Hamilton Boulevard, South Plainfield, NJ 07080; 800-757-8301; Fax: 908-757-9273). Their products can also be reviewed at http://www.tempil.com.
Supercritical Fluids in Fibers Research Considerable interest has been shown in the use of supercritical fluids (SCF) in a wide variety of experimental and research applications. Where such detailed interests exist, applications almost invariably follow.
The use of SCF methods in analytical laboratories has grown substantial over the past few years. This has been applied especially to extraction and chromatographic methods, where the elimination of toxic or difficult solvents has been a boon, along with the accompanying greatly reduced extraction times.
A very interesting application of SCF technology in the fibers sector has recently come out of research work done at the Georgia Institute of Technology. This has focused on the dyeing of fibers, textiles and polymers and likely presages further search for suitable applications in the fibers and polymer sectors.
One of the most popular solvents for using SCF technology is carbon dioxide. This solvent is especially attractive as it is nonflammable, nontoxic and low cost. It is easily separated from other solvents and substrates, and when so released, it is non-polluting. This solvent is particularly useful with polymeric materials, as it behaves as a plasticizer and can swell many polymers. Because of this attribute, its low viscosity and its high solute diffusivity, it can penetrate many polymers with ease. This character also allows the solvent to carry many materials into polymeric substrates, fostering mass transfer processes.
SCF carbon dioxide is easily absorbed by many polymers. In some cases, the solvent can plasticize glassy polymers at relatively low temperatures; with rubbery polymers above their glass transition temperatures, the polymer volume can be substantially increased. These properties can aid in extraction of materials from the polymers, or conversely can aid in the transport of materials as additives or impregnants, depending upon specific conditions employed.
Carbon dioxide is a gas at normal conditions of temperature and pressure. However, if the temperature is sufficiently lowered, the gas can be converted into a solid (dry ice). If the pressure is increased sufficiently, the gaseous carbon dioxide is converted into a solid or a liquid, dependent upon the temperature. At one condition of temperature and pressure, all three phases of the gas (solid, liquid and gas, the triple point) can exist in equilibrium; for carbon dioxide, the triple point is 310 C and 74 bar. pressure. Above this point, the material can generally be maintained in the liquid state, the preferred state for SCF work. By judicious selection of the pressure and temperature, diffusion rates can be controlled for extraction work or for impregnation processes.
The work at Georgia Tech focused on the use of SCF carbon dioxide for the dyeing of fibers, textiles and polymers. Hence, the capability of the system for impregnation was particularly studied. These efforts confirmed the basic capabilities of the system, as reported by others. The research was extended by studying both phases of the dyeing process, the solubilization of the dyestuff molecule and the diffusion into the polymer matrix.
Rather surprisingly, the Georgia Tech researchers found that the dyestuff could have low solubility in the solvent and still be effective in dyeing. They concluded this result was due to the fact that SCF dyeing can be effective because of the high partition coefficient, the dyestuff molecule preferring the polymer environment to that of the solvent. This property made for high dyeing efficiency and minimized dyestuff loses in the disposed liquor and vessel walls.
As might be expected, the treatment did result in the extraction of some oligomers and surface agents from
Researchers Toolbox
polyester fibers, for example. Other researchers have shown that such treatment can also affect fiber morphology, but no more so than the effects of heat and tension.
Despite the fact that special equipment is required to obtain the temperatures and pressures needed, the interesting results of this work, and the inherent simplicity and cleanliness of the process, suggest utility of SCF technology in other fiber research and applications.
For more information, see: Drews, M. J. and Jordan, C., Text. Chem. and Color. 30, 13-20 (1998). The work at Georgia Institute of Technology is summarized at: Kazarian, S. G., Noel, H.B., and Eckert, C.A., Chemtech, 36-41 (July 1999).
Microthermal Analysis Thermal methods of chemical and physical analysis are well-established techniques for characterizing and quantifying the morphology and composition of polymers and fibers. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA) are all useful resources on the palette of the fiber and polymer scientist.
By adding the option of temperature modulation superimposed on the conventional linear heating or cooling program, further information and resolution is possible in many of these cases.
Even with such extensions of the basic techniques, however, these methods give only an averaged or a sample-averaged view of the condition within a polymer matrix. In order to measure the thermal properties of a small domain with the polymer, it is generally necessary to go to a microscopic scale. With some restrictions, secondary ion mass spectroscopy (SIMS) or X-ray photoelectron spectrometry (XPS) can provide some focused information, but these techniques have limitations and complexities.
The efforts to bring together the capabilities of both thermal methods with microscopic techniques have resulted in the commercialization of an instrument called the Micro-Thermal Analyzer™, specifically, the TA 2900. The instrument combines the capabilities of thermal methods and micro visualization. It is achieved by combining an atomic force microscope (AFM) with a thermal probe.
The TA 2900 is capable of providing four images or views of the surface of a sample:
Topography1.
After these images have been acquired, any specific location on the sample can be further analyzed by what the instrument producer calls "Micro-Thermomechanical Analysis" and "Micro-Modulated Differential Thermal Analysis." The manufacturer claims these "micro" techniques are comparable with the usual "macro" counterparts.
By means of this micro-thermal methodology, polymer blends can yield useful information. If the blends are immiscible, a two-phase domain structure results; the thermal properties of each individual domain can then be determined. If a single phase results, indicating miscibility, this becomes apparent from the thermal properties of this main phase.
Similar chemical and physical information can be obtained with this equipment and technology on multi-layered films, indicating the thermal composition and compatibility of the various layers. The thermal nature, leading to precise characterization, of defect areas have also be explored by this technology.
Researchers Toolbox
While the equipment is rather expensive, some consulting physical testing laboratories are acquiring the equipment and offering customized analyses.
Source of the equipment: TA Instruments Ltd., Europe House, Bilton Center, Cleeve Road, Leatherhead, KT 227UQ, Surrey, UK; 44+1372/360-363; Fax: 44+1372/360-135; [email protected].
Wetting of Nonwoven Fabrics The wetting of a nonwoven fabric by water and other liquids is of critical importance in many nonwoven applications. The most obvious situation, and one which has been studied extensively, is the wetting of nonwoven topsheet of a diaper by urine voided by the wearer. A rapid wetout and passage of the liquid through the nonwoven is critical to the performance of baby diapers and similar absorbent sanitary products.
Standard test methods have been developed and carefully studied to measure the property of fabric wetting in this setting. Nonwoven diaper facing typically requires a wet-out or strike-through time of only a few seconds to be acceptable by most converters.
The wetting performance of a fabric can be determined quite simply: Place a drop of water from an eyedropper or similar device to give a relatively constant size drop; carefully observe the drop and determine the time required for the drop to be absorbed into the fabric. Once wetting of the liquid occurs, absorbency into the fabric generally occurs very rapidly. If the droplet stays on the surface as an intact sphere for a considerable period of time, the fabric has poor or no wetting performance.
Water (pure or otherwise) can be replaced by saline solution (0.9 weight percent sodium chloride solution), physiological saline solution (sodium chloride plus other minor constituents), synthetic urine, synthetic menstrual fluid, synthetic blood or a variety of other liquids. The time of wetting can be controlled by a variety of methods, and can also be automated. The time of wetting can usually be determined fairly easily, as the droplet tends to show a somewhat different visual appearance and to spread slightly immediately shortly before disappearing into the interior of the fabric.
For those who want a more precise or quantitative method, variations have been used with some success. For a pure scientific method, the traditional contact angle of the Lucas Washburn equation is often attempted. However, upon study it is soon realized that the scientific contact angle is dependent upon having a smooth, pure, uniform surface where the interface of liquid, solid and gas can be assessed. Looking at the surface of a nonwoven fabric clearly shows that these requirements are not met.
Much work has been done on single fiber wetting to substitute for the shortcomings of a fabric surface characteristics. This can yield considerable useful information, but it often departs substantially from the environment encountered by the drop of liquid on a nonwoven fabric surface.
One approach to measuring the contact angle of nonwoven fabrics was offered by Cusick and Hopkins (Cusick, G.E. and Hopkins, Teresa, INDA Journal of Nonwoven Research, 1, No. 1, pp. 32-34, 1989). This method involves an apparatus which holds the test fabric and can be rotated until the meniscus formed by the liquid and the fabric "disappears," or the liquid at the fabric surface is level.
Clearly, a controlled technique is needed that approximates the control, precision and preciseness and versatility of the contact angle method, while allowing adaptability to the radically different character of a fabric surface.
A useful adaptation and amalgamation of these desires is afforded by a method described in a U.S. patent that was granted a few years ago. The method was originally devised to assess the ability and suitability of a nonwoven filter fabric surface to quickly wet out and pass whole blood, such as involved in a blood bank collection operation. With suitable filtration, depletion of the leucocytes (white blood cells) in the blood can be
Researchers Toolbox
achieved. These are the cells which have surrounded bacteria, viruses and other blood debris; their removal from the collected blood can greatly improve the quality of the blood, and rid it of the normal risk for a transfusion patient.
To be practical, an infusion set-up for injecting the blood into a patient must work correctly every time; a blood filter unit that slows or halts the flow of blood from the collection/storage bag into the patient cannot be tolerated. The pressure driving the blood flow is modest; only that coming from a height of several inches.
As a consequence of a need for a quick, definitive laboratory test, the inventors of this patent fashioned a modified test method that mimics the utility of the contact angle method, applied to the needs and surface of a nonwoven filter medium. Their method is called the "Critical Wetting Surface Tension (CWST)."
The method involves a series of test solutions having a range of surface tensions. A set of test solutions is prepared so that each solution has a surface tension of about 3.0 units different than the other solutions. The set of test solutions is prepared so that it covers the range from pure water (73 dynes/cm) to that of a fluorocarbon liquid (25 to 30 dynes/cm range).
The test is carried out by placing 10 standard-sized drops of a test liquid on the surface of the nonwoven fabric. A timer is started at that time, providing for a 10-minute time interval. The test drops are observed for letting and absorption into the fabric at the end of that time interval. If at least nine of the 10 drops are absorbed within the 10-minute test period, it is concluded that the test solution wets the fabric. If less than nine of the ten drops are absorbed within the 10-minute time period, it is concluded that the liquid does not wet the fabric. Tests are run with the solutions from the set of standard surface tension samples until two test solutions with surface tensions separated by no more than 3.0 dynes/cm are identified, the one test solution wetting the fabric (giving at least nine out of 10 drops that wet the fabric), and the other test solution not wetting the fabric (gives less than nine out of 10 drops that wet the fabric). The fabric wetting performance, CWST, is then calculated as the average surface tension of the two identified test solutions.
While the CWST is not exactly identical with the surface character measured by the critical angle test method, it is a very good empirical substitute, and can nicely characterize a nonwoven fabric surface. Such characterization can be very useful for many situations. There appears to be a relationship with the CWST of a nonwoven fabric and the specific surface energy of the pure polymer making up the fibers of a pure fabric (non-blended fibers). Also, the CWST correlates well with the specific surface energies of the pure polymer making up fibers in a blended fiber fabric. The presence of fiber finish and other surface treatments, additives and modifications that affect the fiber surface can be detected. The importance of surface tensions of the participating liquids of the application can also be delineated.
By using 10 drops of the test fluid, a good average is obtained, even taking into account the non-uniformities of a typical fabric surface. The use of test solutions with relatively small differences in surface tension, and the averaging of data points also helps to even out any abnormalities and departures from strict test methodology.
The end result is a versatile, empirical test method that can be very useful in a variety of applications.
Source: "Device and method for depletion of the leukocyte content of blood and blood components." U.S. Patent No. 4,925,572 (May 15, 1990). Inventor: David B. Pall. Assignee: Pall Corporation.
Kilobytes versus Kibibytes A previous issue of INJ (Vol. 7, No. 2; Spring, 1995) featured a table in the Researcher's Tool Box that outlined the prefixes to be used for increasing and decreasing orders of magnitude. Thus, for an increase of 10, 100 or 1,000 times, a simple prefix can be attached to the basic unit to indicate this increase. Similarly, another set of prefixes can be utilized to indicate decreasing orders of magnitude. By combining the prefixes with
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scientific units, as specified in the SI System, a considerably simplified and consistent notation system results. This system is outlined in the table below.
1024 yotta (Y), from Greek of Latin octo (eight) 1021 zetta (Z), from Latin septem (seven) 1018 exa (F), from Greek hex (six) 1015 peta (P), from Greek pente (five) 1012 tera (T), from Greek teras (monster) 109 giga (G), from Greek gigas (giant) 106 mega (M), from Greek megas (large) 103 kilo (k), from Greek chilioi (thousand) 102 hecto (h), from Greek hekaton (hundred) 101 deka or deca (da), from Greek deka (ten) 10-1 deki (d), from Latin decimus (tenth) 10-2 centi (c), from Latin centum (hundred) 10-5 milli (m), from Latin Mille (thousand) 10-6 micro (m), from Latin micro or Greek mikros (small) 10-9 nano (n), from Latin nanus or Greek nanos (dwarf) 10-12 pico (p), from Spanish pico (a bit) or Italian piccolo (small) 10-15 femto (f), from Danish-Norwegian femten (fifteen) 10-18 atto (a), from Danish-Norwegian atten (eighteen 10-21 zepto (z), from Latin zeptem (seven) 10-24 yocco (y), from Greek or Latin octo (eight)
With the advent of the computer and its accompanying "computerese," these prefixes have been adopted in a similar manner. Thus, everyone knows that a megabyte is one million bytes. And that a gigabyte is a thousand million bytes or one billion bytes. The use of this prefix system is so pervasive that the abbreviation system has been further abbreviated; thus, everybody knows and can respond appropriately when told that a computer has 10 "gig" of memory.
Unfortunately, this system of prefixes applied to the computer situation is not strictly correct. Whereas, the normal scientific system or metric is based on 10 digits, called a decimal system, in computer work a binary system based on a two-digit code is employed. Therefore, a "kilo" in the binary computer system is actually 1,024 instead of 1,000 (2 to the 10th power).
Consequently, the use of the normal metric system prefix is actually incorrect when applied to the computer binary system.
Thus lacking in exactness, two major organizations have adopted new numerical prefixes for numbers in the computer binary system. The International Electro-Technical Commission (IEC) is responsible for international standards for electronic technologies. With considerable imput from the National Institute of Standards and Technology (NIST) in the United States, a new system has been adopted for the binary system. Now, to represent exponentially increasing binary multiples, the IEC has designated kibi (Ki), mebi (MI), gibi (Gi), tebi (Ti), pebi (Pi) and exbi (Ei). Thus a kibibyte is 2 to the 10th power or 1,024 bytes; a mebibyte is 2 to the 20th power, or 1,048,576 bytes; and so forth.
Researchers Toolbox
INJ DEPARTMENTS
STANDARDS DEVELOPMENT FORUM By Chuck Allen, INDA Technical Director
Test Method Harmonization The buzzword in the area of standardized test methods is harmonization (making test methods the same in different parts of the world). As discussed in the last issue of the INJ, there are any number of standards setting organizations worldwide. Each organization has its own process for evaluating and adopting test methods.
One can imagine the technical and political difficulties that could be associated with identical test methods being adopted by two or more of the organizations. Having to use different test methods on the same product, depending on where the product is being sold geographically, presents difficulties and is costly. Laboratories may need to purchase and maintain different pieces of equipment or instruments for testing the same properties of fabrics or products. To be able to generate reliable and reproducible results, lab personnel must become familiar and experienced in conducting the applicable test methods from more than one standard setting source.
Almost all the standard setting organizations recognize there is demand for test method harmonization and are investigating ways of cooperating with each other to reach this difficult goal.
Harmonization In Nonwovens: INDA and EDANA have made test method harmonization a high priority. INDA publishes its own Standard Test Method (STM) manual, which contains over 50 test methods for nonwoven fabrics. Test methods from the STM manual are then moved through the ASTM process, where the goal is to have them all eventually approved as ASTM methods, and in the ASTM format. All the currently adopted ASTM Nonwovens test methods, except for the geotextile methods, originated as INDA Standard Test Methods.
Likewise, EDANA publishes a test method manual, EDANA Recommen-ded Test Methods (ERT), containing over 40 methods for testing nonwoven fabrics. EDANA works through CEN (European Committee for Standardization) and ISO (International Organization for Standards) to have their methods recognized as national and international standards.
The STM and ERT manuals contain many methods that measure the same properties, but the methods have differences. Due to recent correlation activities by the two organizations, there are now five methods that have been harmonized and are identical as contained in the INDA STM and the EDANA ERT manuals.
Work has begun on the next series of five STM and ERT methods scheduled for harmonization. INDA, through the Nonwovens Cooperative Research Center (NCRC) at North Carolina State University, has put together a harmonization document, which is in its final editing stages; this document lists the differences between INDA STM methods and related EDANA, ASTM, TAPPI, ISO and AATCC methods. This document will soon be available through INDA.
Global Harmonization: INDA and EDANA are not the only ones involved in test method harmonization. In late 1998, ASTM and ISO had a meeting to discuss how they could work together more productively. As an outcome, ASTM submitted a pilot program for ISO consideration involving ASTM standards used in the global market where there are no ISO counterpart standards. ASTM would be the developer and maintainer of the standards and would actively seek input from ISO member bodies. The resulting standards would carry an ASTM/ISO designation.
The proposal has met with approval by the ISO leadership task force and has been presented to the ISO council for final approval. At the time of this writing, the outcome is not known, but the vote was expected to take place at the ISO meeting in
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TANDEC Schedules Conference The ninth annual TANDEC Conference will be held November 10-12, 1999 at UT Conference Center, The University of Tennessee, Knoxville, Tennessee, USA and focus on several exciting areas of the nonwovens industry and technology:
Marketing Analysis of Nonwovens
Nonwoven Composites and New Applications
New Technology Development and Opportunities
Fundamental Studies in Nonwovens
Attendees will receive concise and practical information on new nonwoven products and markets, and gain a firm understanding of the latest technological advances in meltblowing, spunbonding and related processes.
TANDEC Conferences feature a broad cross section of speakers, who combine the best aspects of industry, academia and the consulting sphere. Professionals in nonwovens R&D, marketing, production and management will benefit by attending this conference. For additional conference information please meet us in cyberspace at: http://web.utk.edu/tancon. For conference schedule: http://web.utk.edu/tancon/program.html. For registration info: http://web.utk.edu/tancon/registra.html.
July. It is important to note that this new system would be on an individual test method basis. Any communication and cooperation between ASTM and ISO must be considered a step in the right direction toward harmonization.
In Europe, CEN is standardizing methods of its member countries, which include Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. The national standard organizations of the member countries are bound to implement CEN approved European Standards, either by publication of an identical text or by endorsement, and conflicting national standards will be withdrawn within a given time period. This will result in harmonizing test methods used within all the CEN countries.
As can be seen, test method harmonization activities are taking place around the world and are to be applauded. Having global harmonization of test methods is a noble goal that will take lots of work and even then may not be accomplished in all areas. When asked, "Is achieving a single standard practical?" Sergio Mazza, president of ANSI replied, "Sometimes yes, sometimes no. To try to answer this question out of the context of a specific application is completely pointless. In every sector, and sometimes in every instance within a given sector, you're going to get a different answer. I do believe you can make a general statement of principle that you would rather have fewer than more standards, that you want to minimize duplication, that you want to minimize conflict, but in many circumstances you can't eliminate duplication and conflict. You're dealing with different technical infrastructures, or different regulatory infrastructures, in each sector, and in different parts of the world. The challenges are demanding and the goals are worthwhile. Globalization is not a fad. It is here to stay and there is a need and desire for global test method harmonization. "
FORMALDEHYDE TEST METHOD EVALUATION FOR NONWOVEN PRODUCTS
Industry Collection Developmement Specific Interference Range Instrument Ease Time (ppm) AATCC Textile Water Nash Yes Yes 10-3500 Spectrom. Easy Many/day Japanese Japan Water Nash Yes Yes 10-3500 Spectrom. Easy Many/day HPLC ASTM N/A HPLC Yes No >0.05 HPLC Med. Many/day Tube Furnace UF/Glass Air/Temp. DNPH/HPLC Yes No >0.05 HPLC Med. 10-15/day Chamber Wood Air/Temp. ? (Yes) (No) HPLC Med. Limited Humidity Head/Space Chemical Air/Temp GC/MS Yes No >25 GC/MS Med. 8-10/day GC/MS Hard
Formaldehyde Measurements Considerable effort has been focused on formaldehyde, formaldehyde content, formaldehyde analysis and related problems over the past several years. Many concrete and expensive steps have been taken by the Nonwovens industry to ensure compliance with a vast array of regulations.
One of the most positive and helpful activities in this regard has been the TAPPI Binders and Additives Committee work directed
ASSOCIATION FORUM
Oil Spill Cleanup Standards Like many complex activities, techniques for handling oil spills have been spur-of-the-moment and highly empirical. The experience of the last 10 years has provided some useful guidelines in dealing with these calamities, but the technology and procedures are far from being well established. To assist in moving toward a more rational approach to remediating the oil spills and related incidents, the American Society for Testing Materials (ASTM) has initiated an effort to develop oil spill cleanup standards. To that end, ASTM is requesting assistance in developing new standards for shoreline oil spill cleanup and restoration.
Members of oil spill cleanup cooperatives, response teams, oil spill removal organizations, oil companies and others are invited to provide input for develop of these guidelines. This project is under the chairmanship of Dr. Dick Lessard, who is Oil Spill Technology Coordinator for Exxon Research and Engineering.
Additional standards are also being prepared for subcommittee review, including the selection of the appropriate shoreline cleaning techniques and the classification of shoreline types, along with definition and delineation of cleanup materials. Comments in regards to these and other shoreline cleanup standards are also invited.
In view of the fact that meltblown oil sorbants constitute one of the major resources for this activity, a significant contribution from this segment of the nonwovens industry is expected. For further information or to participate in the preparation of these standards, the ASTM contact is Robyn Zelmo, 610-832-9717; Fax: 610-832-9666; [email protected].
Cellulose Aging Study An interesting research project has been initiated by The American Society for Testing and Materials (ASTM). This will involve a century-long study of the effects of natural aging on printing and writing papers. A total of 15 experimental paper types will be stored in volume form by 10 North America universities and government agencies. Normal storage conditions as encountered in a typical library stack will be involved. Samples will be withdrawn from the specimens at various time intervals to follow the changes with time. A century may seem like a long time to wait for results, but it was decided that accelerated aging studies need to be cross-checked
toward the formaldehyde problem. This committee has carried out an aggressive program focused on developing useful facts and technology, while dispelling myths and bias. Status reports of this effort were provided in 1995 and the results of a Round Robin testing exercise were provided in 1996.
This committee recently completed a major phase of their work and has provided a definitive status report on the extensive effort expended. This report was circulated as a separate paper at the recent TAPPI Technical Conference (March, 1999), although it was not presented verbally. This summary report was prepared by the three leaders of the Sub-committee efforts: Michele Mlynar (Rohm and Haas Company); Tom McNeal (Borden, Inc.) and S.J. Wolfersberger (Owens Corning Fiberglas). However, because of the seminal nature of the report, wider circulation is certainly justified.
What follows is an abstract of this report, prepared to provide insight into the essentials and conclusions of the report.
The objective of the "Formaldehyde Testing Task Force" was to review available methods for the measurement of formaldehyde for nonwovens, and to agree on industry measurement standard. The committee identified three areas for formaldehyde measurements related to the nonwoven manufacturing process:
Binders: water-based emulsions, phenol-formaldehyde resins, melamine-formaldehyde resins, and urea-formaldehyde resins.
Stack Emissions: ducts, ventilation systems, venting stacks and other process sources.
Nonwoven Products: formaldehyde content, evolution from disposable, durable and industrial nonwoven products.
Each area was assigned to a committee which reviewed different test methods used by various segment of the industry. These various test methods were evaluated by establishing test criteria and comparing the different methods against these criteria. This report summarizes the formaldehyde test methods evaluated for these three different industry segments.
The committee found that a single method cannot be recommended for each industry segment, but that several methods can often be considered for each segment. This report can be summarized as follows:
Binders: For water-based emulsions, the ASTM Method (#PS-94-4/#D 5910-96) and the AC Method (#AC-7) were examined. The ASTM method has been approved by ASTM and other groups, performs very well, and can be recommended without further evaluation. It is somewhat more complex and more expensive. The AC Method is limited to low pH emulsions. The ASTM Method is preferred.
Phenol-Formaldehyde resins were evaluated by three methods (ISO #9397; #IR-038-05; #M2221.2), all of which use the same analysis mechanism. The methods differ by endpoint pH determination method, inclusion of calibration or blank procedures, and certification. All three methods are more or less equivalent in their results. The ISO (International Standards Organization) Method has industry certification and is the basic recommendation..
Melamine-Formaldehyde resins were only analyzed by the Method
with actual experience. However, the researchers who are initiating the project will not be waiting around for the results
(#ADCH-0188). This method was selected as the resin has a high pH and requires initial neutralization, which is provided for in the method. This method is very similar to the urea-formaldehyde method, after the neutralization step. It is considered to be quite comparable to the UF methods. It provides satisfactory results.
Urea-Formaldehyde resins were subjected to four test methods (#ADCH-0184; #M2221.1; #ACDH-0185; A.P.#32), all of which were based on the same chemistry. Because of the possibility of unwanted hydrolysis of the resin, the methods are rather sensitive to operator technique. All four variations are considered valid and are quite comparable.
Recommendations for using the methods studied are provided. Suggestions on calibrating the analysis, potential sources of error and variation, an indication of precision, etc. are offered for some of the methods.
Stack Emissions: In this category, five test methods were reviewed, but no recommendations were made, as no Round Robin tests have been conducted so far.
The analytical methods considered included the following:
Chromotrophic Acid: Samples are collected in impingers, usually with aqueous 1% sodium bisulfite as the impinger collection solution. Normally, an EPA Method 5 train is used with a heated filter and probe ahead of the impinger sampling train. Impinger samples are analyzed by the chromotropic acid method, forming a purple color proportional to formaldehyde concentration, which is measured in a spectrophotometer at a wavelength of 580 nm.
Dinitrophenylhydrazine Method: Samples are collected in impingers, usually using saturated 2,4,DNPH (dinitrophenylhydrazine) in aqueous 2 NHCl as the impinger collection solution. Normally, an EPA Method 5 train is used with a heated filter and probe ahead of the impinger sampling train. Impinger samples are extracted with methylene chloride, and the extracts are analyzed by liquid chromatography. The chromatographic separation is usually optimized so that a variety of aldehydes and ketones can be determined in a single analysis.
Pararosaniline: Samples are collected in impingers, using high-purity water as the impinger collection solution. Normally, an EPA Method 5 train is used (without a filter) and probe ahead of the impinger sampling train. Impinger samples are analyzed by the pararosaniline method, forming a purple color proportional to formaldehyde concentration, which is measured in a spectrophotometer at a wavelength of 570 nm.
Fourier-Transform Infrared Spectro-scopy: Measurements are made directly on the stack gas, by passing an infrared beam across the stack (in-situ), or by extracting a portion of the gas into a cell. High-resolution infrared spectra are obtained, and interfering spectral features (from compounds such as water, carbon dioxide, etc.) are subtracted from the spectra. The amount of formaldehyde can then be calculated by comparison to a stored reference spectrum of a formaldehyde standard.
Acetylacetone: Samples are collected in impingers, using high-purity water or 10% methanol in water as the impinger collection solution. Normally, an EPA Method 5 train is used with heated filter and probe ahead of the impinger sampling train. Impinger samples are analyzed by the acetylacetone method, forming a yellow color proportional to formaldehyde concentration, which is measured at a wavelength of 412 nm.
It is suggested that Round Robin testing is appropriate in this sector, along with a further study of Head Space/Gas Chromotography/Mass Spectography Detection (GC/MS) Method.
Nonwoven Products: In this industry sector, a total of 10 test methods were submitted and reviewed, including the following:
AATCC Sealed Jar Test #112-1993: This method is used for nonwovens and other textiles employed in the industry. It measures the free formaldehyde plus some of the bound formaldehyde in a fabric.
Tube Furnace Method: This method is specific for urea-formaldehyde and glass mat products. With HPLC development properly carried out, it is very specific for formaldehyde.
Japanese Ministry Ordinance Article #4, Legislation #112, 1973: This method measures the free formaldehyde in a sample, but under some conditions can generate analyte from bound formaldehyde. The method is required for any imports into Japan. It is also growing in use as a standard method for the baby wipe industry.
Chamber Test: This method is used by the wool industry to measure the formaldehyde emission from wool dust particles. It is a dynamic test that could be adapted for nonwovens, but required further development work.
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Head Space/GC/MS: Further work is required to assess the value of this method in comparison to other methods.
LC Pre-Derivatization (High Pressure Liquid Chromatography, HPLC/Nash): This method uses high pressure liquid chromatography to separate the free formaldehyde from the other components, followed by post column derivatization with Nash reagent and visible absorbence detection. It is a method under development, so is not appropriate at this time for a standard.
MITI JIS-L1041-1960: This method is the forerunner of the present Japanese Law 112-1993 and has been replaced by the more recent method. It is not recommended.
KCN Method: This method was not recommended and is not being further studied.
Shirley Institute Test: This test was developed many years ago; it is not recommended and will not receive further work.
The first six method were subjected to further evaluation and rated for characteristics and appropriateness, as summarized above.
It is hoped that individuals who have a definite interest in this report and topic will pursue the matter further. For those who would like to learn more about this project, or make comments on the report and the committee's activities, or to study the material further, a copy of the report can be obtained from Michele Mlynar, Specialty Polymers Group Leader, Fiber and Textile Polymers, Rohm and Haas, Research Laboratories, 727 Norristown Road, P.O. Box 904, Spring House, PA 19477; 215-641-7107; Fax: 215-619-1622; [email protected]
Your comments and suggestions regarding this department and the area of standards development are welcome, please respond to Chuck Allen, [email protected]; INDA, P.O. Box 1288, Cary, N.C. 27513; 919-233-1210, ext. 114, Fax 919-233-1282.
The editors wish to express their appreciation to Mr. Allen for agreeing to develop and edit this column.
—INJ
INJ DEPARTMENTS
PATENT REVIEW Spunbond Fabrics from Nylon and Polyethylene Continuous filament nylon spunbond fabrics are a special category within the spunbond nonwoven classification. The fabrics are produced by a process in which molten nylon-66 resin is extruded into continuous filaments, the filaments are attenuated and drawn pneumatically, and then deposited onto a collection surface to form a continuous filament web. These filaments are bonded together to produce a strong, coherent fabric.
Filament bonding in the case of nylon can be accomplished either thermally or chemically. Thermal bonding is accomplished by passing the web of filaments through the nip of a pair of heated calender rolls; one of the rolls carries a pattern of elevated points providing discontinuous bond sites resulting from the heat and pressure of the calender points.
Chemical or autogenic bonding can also be employed; in this operation, the web of filaments is transported to a chemical bonding station or a "gas house," which exposes the filaments to a mixture of hydrogen chloride gas and water vapor. The water vapor enhances the penetration of the hydrogen chloride gas into the filaments; the mixture causes the filaments to become tacky and thus amenable to autogenic bonding. Upon leaving the bonding station, the web passes between rolls which compact and bond the softened filaments in the web. Adequate bonding is necessary to minimize fabric fuzzing (that is, the presence of unbonded filaments) and to impart good strength properties to the fabric. Autogenic bonding has been especially used in forming spunbond nylon- 66 industrial fabrics.
Whether bonded by the intermittent thermobond process or autogenic bonding agents, these nonwoven fabrics tend to be somewhat stiff and boardy, as produced. This arises from the fact that even with point bonded fabrics, it is frequently difficult or even impossible to strictly limit bonding to the desired points. Filaments that are not compressed by the embossed points are still subject to the heat of the calender and tend to form weak, secondary or "tack" bonds of the filaments outside the desired bond areas. In a similar manner in autogenic bonding, secondary or tack bonds can form between filaments where the area of contact is very limited, giving weak bonds.
In both processes, these weak, secondary bonds promote fabric stiffness, but contribute little to fabric strength and integrity. Consequently, it has been found beneficial to subject such nonwoven fabrics to a
Patent Review
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softening process. This is generally done by subjecting the fabric to mechanical stress. Such treatments are believed to effect softening primarily by breaking the weak, secondary tack bonds, which can be broken without breaking the primary point bonds or those bonds intentionally created to foster strength.
The mechanical stress methods for softening may include the process of washing the fabric, drawing the fabric under tension over sharply angled surface such as a knife blade, stretching the fabric, twisting, crumpling or subjecting the fabric to various combinations of such treatments. The fabrics can also be softened by impinging the fabric with high pressure fluid jets. While these mechanical stress methods are relatively effective, they create many problems, especially in view of a desire to maintain a direct, continuous process.
This patent describes a process for obtaining a soft, yet strong nylon spunbond fabric without the problems associated with the mechanical stress softening steps. This involves the addition of a small amount of polyethylene polymer to the nylon feedstock prior to extrusion. The addition of the polyethylene to the nylon resin enhances specific properties such as softness. The use of polyethylene also lowers the cost of production and eases further downstream processing, such as bonding to other fabrics or to itself.
The improved nylon spunbond fabric is obtained by adding a small amount of polyethyl

1999 - volume 2 - jeff. journal of engineered fibers and fabrics

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