University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 5-2006 Influence of Material ariablesV in Thermal Bonding of Nonwovens Raghavendra Ratnakar Hegde University of Tennessee - Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Materials Science and Engineering Commons Recommended Citation Hegde, Raghavendra Ratnakar, "Influence of Material ariablesV in Thermal Bonding of Nonwovens. " Master's Thesis, University of Tennessee, 2006. https://trace.tennessee.edu/utk_gradthes/1576 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by Raghavendra Ratnakar Hegde entitled "Influence of Material Variables in Thermal Bonding of Nonwovens." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Master of Science, with a major in Materials Science and Engineering. Gajanan Bhat, Major Professor We have read this thesis and recommend its acceptance: Larry C. Wadsworth, Roberto S. Benson Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a thesis written by Raghavendra Ratnakar Hegde entitled "Influence of Material Variables in Thermal Bonding of Nonwovens." I have exam- ined the final electronic copy of this thesis for form and content and recommended that it be accepted in partial fulfillment of the requirements for the degree of Masters of Science, with a major in Material Science and Engineering. Gajanan Bhat Major Professor We have read this thesis and recommend its acceptance: Larry C. Wadsworth Roberto S. Benson Accepted for the Council: Anne Mayhew Vice Chancellor and Dean of Graduate Studies (Original signatures are on file with official student records) Influence of Material Variables in Thermal Bonding of Nonwovens A Thesis Presented for the Master of Science Degree University of Tennessee, Knoxville Raghavendra Ratnakar Hegde May 2006 Copyright © 2006 by Raghavendra Ratnakar Hegde. All rights reserved. ii With love to My Mother – Geeta Bhat Sister-Ramya Vanitakka & Bava Doddappa Doddamma-K G Bhat, Lakshmi K Bhat iii ACKNOWLEDGEMENTS I would like to convey my sincere thanks to my academic and research advisor, Dr. Gajanan Bhat, for allowing me to pursue this research opportunity under his able guidance. I gratefully acknowledge Dr. Larry C. Wadsworth and Dr. Roberto S. Benson for taking interest and serving on my committee. This study would not have been possible without the financial support from NCRC. I would like to express my sincere gratitude to Mr. Andy Campbell Sunoco Chemicals for providing samples for this research and an opportunity to carryout fiber bonding studies at their lab. Thanks to Mr. Dave Gilbert, Tony for their help during research work at SUNOCO Chemicals. I would also like to thank our industrial advisory board especially Exxon-Mobil, KOSA and Goulston for providing samples/materials for this stage of the study. I would like to thank staff and professors of TANDEC for their help through this research. Special thanks to Van Brantley for training me to become acquainted with all nonwoven testing instruments. Thanks to Narahari, Vivek, Ajit and Rahul Vallabh from NCSU for providing the accommodation during the NCRC, IAB meetings. I am very grateful to Dr S. K. Batra, Hooman Vahedi Tafreshi from NCSU College of textiles for providing their lecture notes on thermal bonding. Thanks to Qi Qi Wang, Ajit from NCSU for help- ing to chuck out related thesis reports from NCSU main library. Thanks to Doddappa, Doddamma, Vidyakka, Sadanandanna and Anjanakka, for all their moral support, encouragement, care and love they have always given me. Spe- cial thanks to Vanitakka and Bava for their suggestion and support to continue my further education, during my job searching time in Bangalore. iv Finally and most importantly I express my special gratitude to my Mother Geeta G Bhat, Sister Ramya for believing in my goal, and giving their constant support, love and encouragement. A big ‘Thank you!’ to Vanitakka, Bava, Sneha and Sunay in Knoxville for all their love, support during my stay here and making me feel at home every time I visited them. Special thanks to my friend MG Kamath for all his support, guidance and training through my stay in Knoxville. I would like to thank my colleagues and friends in Materials science and Engineering department: Atul Dahiya, Chris Stephens, Eliza- beth Barker, George Jacob, Indraneel Sen, Kshitish, Kai, Mohan damu, Prabhakar, Ranjan Ramchandra, , Sherry, Shelly, Stacey, Vasu Hariharan for all their help and support during my Masters degree. I wish to thank my friends in Knoxville: Aditya, Achut, Gagan Rajpal, Gaurav, Geoffery, Shane, Ikram, Karthikeyan, Mardav Wala, Madan, Mazaj, Michel, Mug- dha, Pranita, Rajgopal, Ramya, Ranjan, Sriram, Sriram, Maheshdorai, Magaz, Sampath, Ravi, Ravi Ram Chandra, Rishi Mehta, Sunil Sahu, Shraddha, Srikala, Shravan, Shakti, Sandeep, Sumesh, Tushti, Lucia, Vasu Hariharan, Kshitish, for their wonderful time, support, help and making me not to miss my home during my stay. v ABSTRACT The goal of this research was to understand the bonding behavior of different poly- mers in thermal bonding. Special attention was given to the interaction of the materials variables with processing characteristics of the polymers. Initially, thermal bonding studies were done using films from different polymers. Polymer films of different morphology were produced from different grades of polypropylene. Thermal bonding of these films was carried out using the hot press. Effect of film structure, properties and bonding conditions on the bonding efficiency was studied. A range of bond temperatures covering poor, optimum and over bond- ing were studied to understand the changes taking place. Bonded film strength was analyzed using tensile testing. Change taking place to polymer in bond point and original surface were analyzed using SEM. Importance was given to material vari- ables of bonding and their influence on the bond strength are scrutinized in this work. Films bonded at lower sealing pressure and time gave better results. Films with lower orientation formed better bond. Bonding studies on films were extended to fibers and webs. Polypropylene fibers manufactured with different processing conditions and with different cross-section, denier, and polymer melt-flow rate were bonded with different heat sealers. Bonding studies were also done with several sheath-core bi-component fibers. Fiber bond strength results were similar to results observed in case of films with respect to bonding temperatures studied. Carded webs were prepared from polypro- pylene and other bi-component fibers. Effect of bonding temperature on property of calendered web was determined using tensile, tear and stiffness testing. Fiber web mechanical properties increased with the calendering temperature. At higher calen- dering temperature strength increased along with the stiffness. After certain optimum temperature, properties of the webs deteriorated. vi Impact of spin finishes on the thermal bond strength was studied. Thermal bonding studies of polymer film, fibers and fiber webs with two different finishes at different concentration levels were carried out. In most of the cases, bond strength was lower compared to those without any finish, and the strength drop was higher with higher level of finish. Film, staple fiber and fiber web attained its optimum strength at slightly higher bonding temperature in the presence of finish. vii CONTENTS 1.................................................................................................................................... 1 INTRODUCTION ....................................................................................................... 1 1.1 JUSTIFICATION ........................................................................................ 4 1.2 THESIS GOALS.......................................................................................... 5 2.................................................................................................................................... 6 LITERATURE REVIEW ............................................................................................ 6 2.1 NONWOVENS............................................................................................ 6 2.2 WORLDWIDE NONWOVEN STATISTICS............................................. 8 2.3 MANUFACTURING PROCESSES ........................................................... 9 2.4 PRODUCTION OF NONWOVENS......................................................... 11 2.5 BONDING ................................................................................................. 11 2.5.1 MECHANICAL BONDING ..................................................................... 12 2.5.2 CHEMICAL BONDING ........................................................................... 12 2.5.3 THERMAL BONDING............................................................................