6480(Print), ISSN (Online) Volume 5, Issue 2, February (2014), pp , IAEME AND TECHNOLOGY (IJARET)

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1 International INTERNATIONAL Journal of Advanced JOURNAL Research OF ADVANCED in Engineering RESEARCH and Technology IN (IJARET), ENGINEERING ISSN 0976 AND TECHNOLOGY (IJARET) ISSN (Print) ISSN (Online) Volume 5, Issue 2, February (2014), pp IAEME: Journal Impact Factor (2014): (Calculated by GISI) IJARET I A E M E AN ECO-FRIENDLY RUBBER-TEXTILE COMPOSITES FOR CONSTRUCTION OF RUBBER DAM TO USE IN WATERSHEDS APPLICATION K. Rajkumar, P. Thavamani, Chandresh Dwivedi*, PankajRegar Indian Rubber Manufacturers Research Association (IRMRA), Plot No 254/ 1B, Road No. 16V, Wagle Industrial Estate, Thane, India ABSTRACT Rubber dam is a unique rubber-textile composite, in which technical textiles acts as reinforcing and strength providing material, whereas rubber acts as shock absorber and water proofing material. Basically Rubber dam consists of rubber-textile composite sheet, concrete base, anchoring system, inflation deflation device (pump). In rubber textile composite, rubber to fabric adhesion plays the most critical role for determining assembly process and ultimate strength of product. A vulcanizable adhesive for rubber to fabric fabrication of composite material was developed which was compatible with rubber as well as fabric. Evaluation of bonding system with respect to peel strength, breaking strength, shear adhesion strength, types and design (weave pattern) of fabrics, were the major determining criteria for selection and optimization of fabric for Rubber Dam application. Thus the optimized adhesive system has been developed with the characteristics of high adhesive strength and good compatibility with rubber as well as with fabric. The potential application of these technical textiles with natural rubber composites is in the development of rubber dam. Rubber Dams are resistant to abrasion, corrosion, earthquake, radiation and these require zero maintenance. Weave patterns of fabrics is also an important criteria for Rubber to fabric adhesion; thus Mockleno weave pattern gives better adhesion strength with rubber than Honeycomb and Matt weave patterns. Layout of composite sheet was optimized on the basis of breaking strength and peel strength. Nylon fabrics are polar in nature, so gives better adhesion than non-polar Polyester fabrics. Bonding adhesive systems for treatment of fabrics were developed such as Resorcinol- Formaldehyde-Latex (RFL) for Nylon 6, 66 and Grillbond (Blocked poly iso-cyanate) for Polyester fabrics. Rubber compounds for cover layer and cushion/friction layer were optimized on the basis of required properties such as tensile strength, tear strength, elongation at break, hardness, ageing resistance, water resistance etc. Various types of Nylon 6, 66 fabrics were tried with natural rubber for peel strength and bonding evaluation and one was optimized according to best required properties 128

2 for Rubber Dam application. Trials with polyester fabrics were also taken due to various advantages of polyester fabrics such as low cost, easy availability and low moisture regain over Nylon fabrics. To overcome the adhesion problem with polyester fabric, a special chemical treatment was given. Keywords: Natural Rubber, Technical Textiles (Nylon6, Nylon 66, Polyester Fabrics), Adhesive, Adhesion, Composite, Rubber Dam. INTRODUCTION Technical textiles have attracted considerable attention and technical textiles were widely used to encompass all textile products other than those intended for apparel, household and furnishing end uses. Industrial textiles are now more often viewed as a subgroup of a wider category of technical textiles, referring specifically to those textile products used for industrial application such as filters, machine clothing, conveyor and v-belts, inflatable products for marine application abrasive substrates etc. In the composites industry, woven, knitted, braided, non-woven and wound yarn reinforcement made from glass, carbon fiber and organic polymer materials such as Nylon, Polyesters, Aramid are all now widely used. Polyamide (Nylon) and Polyester fabrics are extensively used as reinforcing material for flexible rubber composites such as fan belts, hoses, flexible drivers, tires and other applications. They account for 28 and 48% of the total synthetic fiber production. Woven fabrics exhibit good stability in the warp and weft directions and offer the highest yarn packing density in relation to fabric thickness. The adhesion of fabric to rubber plays the most critical role to ensure the life of the flexible composite of rubber dam. To impart good bonding between rubbers to technical textile, an adhesive must not only hold materials together but also withstand operating loads and also be resistant to operating medium to ensure the life of the product. In this context a good bonding agent or adhesive and its concentration should be optimized with respect to types of fabrics, weaving pattern and gsm. We tried different types of Nylons, Polyester fabrics for the evaluation of natural rubber to fabric adhesion. Nylon fabrics have good impact resistance, breaking strength and flexibility. Due to higher polarity, Nylon fabric should have a better adhesion compared to polyester fabric. Whereas Polyester fabric is less flexible than Nylon but has better breaking strength and excellent moisture resistance. Nylons have a limitation for moisture absorption when used in dampen environment. The adhesion property of the polyester fabric was further enhanced by activating its surface. Rubber dams are inflatable and deflectable hydraulic structures. Thousands of rubber dams have been installed worldwide for various purposes: irrigation, water supply, power generation, tidal barrier, flood control, environmental improvement, and recreation. Furthermore, rubber dams have been used in cold areas where the temperature is as low as 40 C. The simplicity and flexibility of the rubber dam structure and its proven reliability are key considerations in its wide scope of applications. The total investment cost of rubber dams being about 40% lower than the conventional gated regulating structure, the utility of the same is much greater in as much as it addresses the age old problems of flood, droughts, low water efficiency, excessive dependence on monsoon etc. EXPERIMENTAL Materials Carbon black (SRF N774) was supplied by M/s Specialty Carbon and Chemicals Ltd, Mumbai. Rubber chemicals like antioxidants and accelerators were supplied by M/s Vinhar chemicals Pvt. Ltd., Mumbai. Zinc oxide, Stearic acid and Sulphur were supplied by M/s RubbosynthImpex Pvt.Ltd., Mumbai. Natural Rubber (RSS-4) was supplied by M/s Shreeji 129

3 Enterprises, Mumbai. All the fabrics were supplied by M/s Kusumgar Corporates, Mumbai. Dry bonding agents (Cohedur RK and Cohedur A250 as shown in table 2) were supplied by M/s Lanxess India Ltd., Mumbai. Silica and DEG were supplied by M/s B.P Chemicals, Mumbai. Formulations of rubber compounds are given in tables 1 and fabric types are given in tables 2, 3 and 4. Preparation of Samples Six different types of cushioncompounds (three with and three without dry-bonding agent) were prepared. Compounding was done using open two roll mixing mill % rubber solution was prepared in solvent xylene, under stirring condition and was applied on the treated fabrics by spray gun technique. Two different set of Nylon fabrics were tested (Nylon 6 and Nylon 66), i.e. nine type Nylon-6 and nine type Nylon 66 samples were tested. Testing sample specimens were made as per layout using compression moulding technique. Processing parameters were determined on the basis of rheometric studies of cushion compounds. Sheet of cushion compound of thickness of 3 mm was applied on both the sides of coated fabric and was molded at 150ºC with required optimum curing time as per rheometric studies data. Peel strength was measured as per test method ASTM D 413, tensile properties were measured as per ASTM D 412 and ageing properties was measured as per ASTM D573. Formulations of rubber compounds Table 1 shows, formulations of NR based cushion compounds without dry bonding and with dry bonding. Total six different types of cushion compounds were prepared, three without dry bonding(dn1, DN2, DN3) and three with dry bonding (DN*1, DN*2 and DN*3) by adding two types of dry bonding in them, DB Cohedur RK and DB Cohedur A250 with 3 and 4 phr respectively. Table 1. Formulations of NR cushion compounds (Phr) Raw Materials (Phr) DN*1 DN*2 DN*3 DN1 DN2 DN3 NR (RMA-IX) Zinc Oxide Stearic Acid TDQ SRF N Silica VN DEG CI Resin DB Cohedur RK * DB Cohedur A250 * CBS Sulphur Total Composition of dry bonding agents:- *DB Cohedur RK (Dry bonding agent, Component-1):- Resorcinol-Silica blend or equivalent *DB Cohedur A250 (Dry bonding agent, Component-2):-HMT/Hexamethylenetetramine (Formaldehyde donor)-silica blend or equivalent. 130

4 Details of Nylon 6, Nylon 66 and Polyester fabrics used Table 2, 3 and 4 shows, details of Nylon 6, Nylon 66 and Polyester fabrics used in present study with their fabric types, weave pattern, GSM, breaking strength and finished width. Honeycomb and Mockleno are open type weave patterns while Matt is closed type weave pattern. Table 2. Details of RFL treated Nylon-6 fabrics used in present study Fabric types Weave pattern GSM Thickness (mm) Breaking Strength Kg/5cm Warp Weft 3297 Matt Honeycomb Mockleno Matt Mockleno Honeycomb Matt Mockleno Honeycomb Table3. Details of RFL treated Nylon-66 fabrics used in present study Fabric types Weave pattern GSM Thickness (mm) Breaking Strength Kg/5cm warp weft 3360 Matt Honeycomb Mockleno Matt Mockleno Honeycomb Matt Mockleno Honeycomb

5 Table 4. Details of Grillbond treated Polyester fabrics used in present study Fabric types Weave pattern GSM Finished width (m) M2AP1 Matt M2AP2 Honeycomb M2AP3 Matt M2AP4 Honeycomb M2AP5 Matt M2AP6 Honeycomb M2AP7 Matt Details of formulations of adhesive systems (RFL and Grillbond) used for treatment of fabrics Table 5, shows typical formulation of Resorcinol-Formaldehyde-Latex (RFL) adhesive for treatment of Nylon 6 and Nylon 66 fabrics and Table 6 shows, Grillbond (Blocked Poly-iso-cyanate) adhesive for treatment of Polyester fabrics. Table 5. Typical formulation of RFL based adhesive treatment for Nylon fabrics Component Parts (Wet) Parts (Dry) Resorcinol Formalin (37%) Sodium hydroxide (10%) Water VP latex (40%) Water Total Table 6. Typical formulation of pre -dip for Polyester fabric based on Grillbond (Blocked Poly-isocyanate) Component Parts (Wet) Parts (Dry) Blocked poly- isocyanate# (40% dispersion) Epoxy resin^ Gum tragacanth solution (2%) Dispersant (50%) Water Total # Grillbond IL6, a caprolactum blocked methylene bis (phenyl di-isocyanate) ^ Decancol NER 010a, a liquid epoxy resin derived from epichlorohydrin and glycerol 132

6 RESULTS AND DISCUSSION Peel strength of different fabrics with rubber compounds has been tested and their bonding evaluation occurred. Table 8 shows, the peel strength of nylon-6 without dry-bonding system. As the peel strength are not adequate certain additives was included in rubber formulation to promote adhesion directly with the fabric and these are, in-situ or direct/dry bonding systems. These systems rely on the inclusion into the rubber matrix of resorcinol (or a resorcinol/formaldehyde precondensate) together with a methylene donor. The addition of these two components will give a moderate level of adhesion. The original methylene donor used for this system was hexamethylenetetramine. While this was perfectly adequate as a methylene donor from the adhesion point, it also significantly affected the cure system, and thus alternative materials have been used, especially hexamethoxy methyl melamine. Comparing Table 8 and Table 9, it is clear that peel strength has increased with addition of dry bonding agent. DN3 compound was optimized considering its Optimum cure time, Tensile strength, Elongation at break, Hardness and Tear strength.from Table 9, it has been observed that in all the fabrics, peel strength are higher in weft direction. This implies that rubber to fabric bonding is better in weft direction. This may be justified by the facts that, fabrics are more stretched in warp direction because of the stretching at the time of fabric manufacturing. So, when frictioning of rubber into fabric occurs, the penetration of rubber into woven fabric is more in the weft direction than in warp direction. This increases the adhesion strength or peel strength in weft direction. Comparing Tables 8, 9, 10 and 11, Nylon 6 fabrics gives better peel strength than Nylon 66 fabrics. We have also tried with different polyester fabrics for bonding evaluation. However, in order to achieve satisfactory levels with polyester, it is necessary to use a pre-treated polyester yarn. Peel strength of RFL treated polyester fabrics was very low, but after treatment of these fabric with Grillbond (Blocked polyisocyanate), we got very good adhesion strength. The dry-bonding systems can be used alone, with untreated fabrics. However, if they are used in conjunction with adhesive dipped fabrics, both systems will contribute to the adhesion, and achieved levels can be significantly higher than with either system alone. From Table 15, it is clearly shown that 100% VP latex (in RFL) treated Nylon 6 and Nylon 66 fabrics shows higher peel strength than 50-50% SBR latex treated and 100% SBR latex treated fabrics. Table 7, shows rheological and physico-mechanical properties of NR based friction compounds without and with dry bonding. From the table, it has been concluded that DN3 friction compound shows highest tensile strength and other physical properties so it was optimized as friction compound for Rubber Dam application. Table 7. Rheological and Physico-mechanical properties of NR based friction compounds without and with dry bonding agent (Cured at 150 C) Property Unit DN*1 DN*2 DN*3 DN1 DN2 DN3 Optimum cure time Min. (150ºC) Tensile strength MPa Elongation at Break % Hardness Shore A Tear Strength Kg/cm

7 Table 8. Peel Strength (Kg/cm) of RFL treated Nylon-6 fabrics (Warp direction) with friction compounds, DN*3 (without dry bonding) Nylon 6 fabrics (RFL Average DN*1 DN*2 DN*3 treated) Table 9. Peel strength (Kg/cm) of RFL treated Nylon 6 fabrics with DN3 friction compound (with dry bonding agent) Nylon-6 fabrics (RFL treated) Peel Strength (Kg/cm) Weft direction Warp direction Average Table 10. Peel strength (Kg/cm) of RFL treated Nylon 66 fabrics with DN*3 friction compound (Without dry bonding) Nylon-66 fabrics (RFL Peel strength (Kg/cm) treated) Weft direction Warp direction Average

8 Table 11. Peel strength (Kg/cm) of RFL treated Nylon 66 fabrics with DN3 compound (With dry bonding) Nylon 66 fabrics (RFL treated) Peel strength in warp direction (Kg/cm) Table 12 shows, comparative peel strength of different types of polyester fabrics treated with RFL and Grillbond. From table, it is concluded that peel strengths of Grillbond treated polyester fabrics is much higher than the RFL treated and shows good bonding with rubber compound. Table 12. Comparative peel strength (Kg/cm) of Polyester fabrics (RFL treated and Grillbond treatment) with DN3 cushion compound (With dry bonding) Polyester fabrics Average Peel strength, Kg/cm (RFL treated) Average Peel strength, Kg/cm (Grillbond treated) M2AP M2AP M2AP M2AP M2AP M2AP M2AP Average peel strength (RFL treated) Average peel strength (Grillbond treated) Average peel strength (Kg/cm) M2AP1 M2AP2 M2AP3 M2AP4 M2AP5 M2AP6 M2AP7 Polyester fabric types Figure 1. Comparative peel strength of Polyester fabrics treated with RFL and Grillbond 135

9 Average peel strength of all Grillbond treated fabrics is much higher than RFL treated one. Table 13. Peel strength of fabrics treated by SBR latex and VP latex with different proportion Fabric code Fabric type Treatment type Average peel strength (kg/cm) 3301 Nylon % VP Latex Nylon 6 VP:SBR (50:50) Latex Nylon % SBR Latex Nylon % VP Latex Nylon 66 VP:SBR (50:50) Latex Nylon % SBR Latex % VP latex VP:SBR(50:50) latex 100% SBR latex Nylon6 (3301) Nylon 66 (3304) Figure 2. Comparative Peel strength of VP latex treated, VP-SBR latex treated and SBR latex treated Nylon 6 and Nylon 66 fabrics CONCLUSION 1. For improving rubber to fabric adhesion, dry bonding agent is required in rubber compound in suitable proportion. 2. Nylon fabrics gives better adhesion with NR friction compound with dry bonding than compound without dry bonding. 3. It has been also observed that, Nylon 6 fabric gives better adhesion than Nylon 66 fabric with NR based friction compound. 4. Nylon fabrics give better adhesion than Polyester fabrics with rubber compounds. 5. Weaving pattern and direction of the fabric type also plays an important role for the adhesion. Fabrics with Mockleno weave pattern shows better adhesion strength than honeycomb and matt. Fabrics used in weft direction shows better adhesion strength than used in warp direction. 6. VP latex treated Nylon fabrics gives better adhesion with DN3 (with dry bonding agent) compound compared with SBR latex treated Nylon fabrics. 7. DN3 compound was selected as a best cushion compound on the basis of required properties. 8. Dry bonding agent gives better adhesion with RFL treated fabrics. 136

10 9. VP latex treated Nylon fabric gives better result compared with RFL treated fabric, even without dry bonding agent. 10. Grillbond (Blocked Poly-isocyanate) treated Polyester fabrics shows improved adhesion strength than RFL treated polyester fabrics. REFERENCES 1. P. Roy Choudhury, S. K. Chakraborty, ManasiNath Rubber Dam a novel approach for control of water flow in water shed management for agricultural growth of India, published in Rubber India, vol LX, No 8, pg 49, August P. Roy Choudhury,ManasiNath, BhagabatBhuyan Design and Development of Rubber Dam a farmer friendly rubber reservoir, published in Rubber Chem Review, vol. XXXVII No. 6, pg. 29, July- August P. Roy Choudhury, S. K. Chakraborty, ManasiNath Bonding evaluation of technical textile with rubber for rubber dam application published in technical proceedings of 5 th International Conference a/c Rubber Expo IRE 09, on 28 th 31 st January, 2009, Kolkata, organized by All India Rubber Industries Association and Kharagpur IIT, pg P. Roy Choudhury, S. K. Chakraborty and PankajRegar, Engineering Aspects of Innovative Rubber Dams for Watersheds, published in Rubber Chem Review, vol. XXXX No.5, Pg 36, May-June D. Wootton in Handbook of Rubber Bonding, Bryan Crowther, Ed., Rapra Technology Ltd., Shropshire, UK, Paper on The adhesion of Polyester textile to rubber published in Rubber world Jan 02 page 21 by Song Yuexian, Wang Youdoo and XuChuanxiang, Xian Jiatong University. 7. X. Q. Zhang, P.W. M. Tam and W Zheng (2002). Construction, Operation and maintenance of rubber dams, Can J. Civ. Eng, 29 (3): M. K. Talukdar, S. K. Chattopadhyay, and B.P Pal, Design and Development of Fabric Substrate for Flexible Rubber Dams presented in The International Conference on Technical Textiles and Nonwovens, organized by IIT Delhi, from 11 to 13 th November S. K. Chattopadhyay, M. K. Talukdar and A. K. Bharimalla, Application of Technical Textile in Fabricating Flexi dam for Water Management in Agriculture, National seminar on Non Conventional Applications of Textiles, 11 Dec. 2010, held at CIRCOT, Mumbai. 10. D. Wootton in Handbook of Rubber Bonding, Bryan Crowther, Ed., Rapra Technology Ltd., Shropshire, UK, M. Lee in Encyclopedia of Composites, vol 2 Wiley, NY, A. F. Richards in Synthetic Fibres J.E. Mclntyre, Ed., UK, ASTM D a. (1998). Fordetermination of the physico-mechanicalproperties using a fully computerized Instron tensile testing machine N.Ganesan, Bharati Raj, A.P.Shashikala and Nandini S.Nair, Effect of Steel Fibres on the Strength and Behaviour of Self Compacting Rubberised Concrete, International Journal of Civil Engineering & Technology (IJCIET), Volume 3, Issue 2, 2012, pp , ISSN Print: , ISSN Online: M. Venu and P. N. Rao, Study of Rubber Aggregates in Concrete: An Experimental Investigation, International Journal of Civil Engineering & Technology (IJCIET), Volume 1, Issue 1, 2010, pp , ISSN Print: , ISSN Online: