Contents
Foreword by Alan E. Learned vii
Foreword by Vlodek Gabara ix
Preface xi
1 Cut and slash hazards 1
2 Evaluate cut resistance 15
2.1 ISO13997 15
2.2 EN388:2016 and ISO23388:2018 21
2.3 ASTM F2992/F2992M-15 34
2.4 ISO13998 40
2.5 ISO13999 44
2.5.1 ISO13999-3 45
2.5.2 ISO13999-2 48
2.5.3 ISO13999-1 49
2.6 Cut resistance for protection against chainsaw 50
2.6.1 ISO and EN standards series for chainsaw protection 50
2.6.2 ASTM standards series for chainsaw protection 53
3 Fundamental of fibers 59
3.1 Basic forms of fibers 59
3.1.1 Staple and staple spun yarn 61
3.1.2 Filament yarn 81
3.1.3 Textured yarn 81
3.1.4 Composite yarn: core-spun yarn and wrapped yarn 87
3.2 Basic properties of fibers 96
3.2.1 Linear density 96
3.2.2 Mechanical properties 101
3.2.3 Hairiness 107
3.2.4 Yarn evenness 107
3.2.5 Twist 109
4 Convert fiber to textile 111
4.1 Knitting 111
4.2 Weaving 121
4.3 Nonwoven 125
5 Choice of materials for cut protective textile 129
5.1 Spinning 129
5.1.1 Melt spinning 129
5.1.2 Solution spinning 129
5.2 Materials 133
5.2.1 para-Aramid 133
5.2.2 High-strength polyethylene (ultrahigh molecular weight polyethylene) 147
5.2.3 Glass fiber 165
5.2.4 Steel wire 169
5.2.5 Nylon fiber 175
5.2.6 Polyester fiber 176
5.2.7 Wholly aromatic polyester fiber 180
5.2.8 Cotton fiber 185
5.2.9 Poly-p-phenylene benzobisoxazole fiber 186
5.2.10 High strength and high modulus polypropylene fiber 188
5.2.11 Polyvinyl alcohol fiber 190
5.2.12 Basalt fiber 193
5.2.13 Polyimide fiber 194
5.2.14 Tungsten wire 198
5.2.15 Other fibers 200
5.3 Dipping or coating materials for cut protective textile 201
5.3.1 Solvent-borne polyurethane 206
5.3.2 Water-borne polyurethane dispersion/emulsion 212
5.3.3 Natural rubber latex 212
5.3.4 Nitrile rubber latex 214
5.3.5 Chloroprene latex 216
5.3.6 Polyvinyl chloride dipping or dotting 216
5.3.7 Silicone rubber dotting 217
5.3.8 Other coating materials 218
6 Mechanism of cut and cut resistance, factors affecting cut
resistance, and development trend of cut resistant products 219
6.1 Mechanism of cut 219
6.2 Factors affecting cut resistance 224
6.3 Development trend and measures to improve cut resistance 228
Appendix A: Conversions between different units of tenacity and strength 233
Appendix B: Data in patents 235
Appendix C: Statistical analysis for data in patents 237
Appendix D: Physical properties of materials 241
Appendix E: Constructions of knit fabric with different fibers 245
References 247
Index 273
Preface
The awareness of and demand for safety protection have been constantly increasing along with the ongoing development of our global economies. Worldwide, the developed countries are leading in the legislation and execution for labor protection as well as the development and use of personal protective equipment, which set examples for and can be used by the developing countries.
I used to work in DuPont for many years on the applications of aramid fibers. In the manufacturing sector, the safety system and practices of DuPont have been well known across the world and have been viewed by many as setting the highest bar of safety performance in industry. DuPont has also participated in establishing many safety standards in the United States. I have experienced and learned tremendously both safety theory and practice during working in the laboratories in DuPont. In the DuPont manufacturing groups, safety contacts, auditing, and training were expected on each shift of every day. . .7 days per week. . .365 days per year. In nonmanufacturing group, safety is also a daily topic. In the R&D labs I worked, besides all the safety measures and information exchange done on a daily basis, a formal monthly safety training was mandatory for every employee. The training covered different contents each month, such as electric safety, hand safety, machinery safety, chemical safety, household safety, sports safety, motorcycle and bicycle safety, pedestrian safety, children safety, sometimes latest changes in laws and regulations such as new traffic laws. I always left my cell phones in office and sat in front of the training class in order for me to focus on the training. More than 10 years, such experience in training also benefits me tremendously.
I had the opportunity to get hands-on and participate in upgrading many types of equipment and processes to improve the safety. As I handled lots of equipment, in DuPont’s machinery safety management standard and practice have tremendously benefited me at my job.
The safety practices of DuPont not only cover on-the-job areas, but also extend to off-the-job, especially to the employees’ families, for instance, household safety, appliance safety, children safety. The strict policy of safety belt use and the penalty for not using also help to save lives of my colleagues who became involved in traffic accidents. I always remember a surprising moment in Shanghai, China that a taxi driver told me that I must be from DuPont when I got into his taxi and insisted on getting the seat belt to fasten. Influenced by the safety culture of DuPont, many employees equip fire extinguishers at home, which is not common in China. This did save one of my colleagues’ family in a home fire incident.
In addition, aramid fibers are widely used in protective products. As my technical field was in aramid fibers, I did extensive research and development in cut protective products. A large portion of workplace injuries are hand injuries, with mechanical hazards, including cuts, being the most common. However, a search of the literature reveals that no definitive books have been written on this very important topic. Likewise there is also very limited academic research published on this subject. After having conducted extensive research and development in cut protective products during my career, I felt compelled to summarize the critical knowledge on this topic. I hope that readers of this book will be able to better understand the complexities of cut protection and continue to advance the technology in a way that helps to protect more people in their daily work for the decades to come. Originally, I intended to write a book on all major applications of aramid fiber, in which cut protection was supposed to be only one chapter. But during the writing of this chapter, the contents were gradually expanded and eventually became a standalone book. Some basic knowledge of textile and fiber materials is added, and thus this book can be used for all practitioners in this industry along the entire value chain. No confidential information from DuPont was used in writing this book.
As I have a full-time busy job and also demanding family needs, I can only use part of the weekends and holidays to write this book to make sure this writing work does not conflict with the full-time job and family needs. It has been a difficult journey. I got up at 5:30 a.m. on every weekend day and holiday during the 2 years of writing, including in the coldest winter, and write until 8:30 or 9 a.m. when my daughters started to be active. Though this book is not long, it still took me more than 2 years to complete. I hereby would like to appreciate my family for their tolerance, especially my two daughters Esther and Joy. Though they really wanted to play with me, they knew I was rushing to complete this book and therefore behaved very well not to disturb my writing. Thank you Esther and Joy, you are my sunshine. And to my lovely wife, none of this would be possible without your love and support. You are my rock and my inspiration.
I would like to extend my appreciation to Dr. Alan E. Learned and Dr. Vlodek Gabara. Dr. Learned used to lead the DuPont global personal protection technology team in aramid business and now has already retired. Dr. Learned helped me review the entire book and gave invaluable suggestions and also helped me on the language in this book. Dr. Gabara used to be a DuPont Fellow and had spent most of his career on aramid technology. He is a worldwide recognized high performance fiber expert and has played a critical role in commercial success of Kevlar and Nomx aramid fibers. He therefore earned a name of “Godfather of Kevlar Fiber.” He has retired from DuPont. Dr. Gabara has been a role model for me in my technical career and encouraged me to write something from application aspect. He helped me review the book.
I would also like to extend my appreciation to Larry J. Prickett, a productive researcher in DuPont. Larry has worked on Kevlar aramid fiber for more than 40 years and developed many cut protective products containing Kevalr aramid fiber. He is a very kind coach and taught me a lot in cut protection and cut protective products.