Proceedings of the Research Symposium of Uva Wellassa University, November 28-29, 2013

Improving of Adhesion in Laminated Rubber Glove Process and Incorporation of Recycled Coagulated Centrifuged Latex

R.G.N Lakmali Uva Wellassa University, Badulla, Sri Lanka

T.Ranasinghe Workwear Lanka (Pvt) Ltd, No.78, Export Processing Zone, Biyagama, Sri Lanka

And H.A.S.L jayasinghe

Uva Wellassa University, Badulla, Sri Lanka

Introduction

Laminated glove is a household glove use for the heavy duty purposes and commonly good manufacturing for construction industry all over the world. Laminated Rubber sheet is used as a composite to palm area with textile fabrics to form proofed material in laminated rubber glove process (Polaski et al., 2005).Poly aramid (Kevlar) and Cotton are the main fabric types which are used and the high adhesion ability between the fabric and laminated rubber layer spontaneously maintain the high resistance ability, quality and high demand in the international market. The absence of sufficient adhesion causes to separate of laminated rubber sheet from the fabric and low quality. The incorporation of coagulated centrifuged latex with the laminated glove process is a better solution for cost reduction and waste minimization. The waste discharges from the centrifuged latex storage tanks unable to direct incorporate with laminated glove processing due to high moisture content. Reducing of excess moisture content up to favorable amount and convert these waste discharges as a recycled rubber with suitable conditions allow to incorporate with the relevant process (Barghoorn et al., 2003)

Methodology

. This research was carried out to enhance the adhesion ability between the laminated rubber sheet and two types of fabrics, Kevlar and Cotton while introducing of new method to incorporate wasted coagulated centrifuged latex with the laminated rubber sheet manufacturing after recycling.

The current study was carried out at Workwear Lanka (Pvt) Ltd, Biyagama. Laboratory analyses were done at Company, Rubber Research Institute and Industrial Development Board laboratories of Sri Lanka. Four experimental trials with different treatments were conducted during this study. The preliminary experiment was conducted to identify the major process steps which are affecting to adhesion of the glove. The adhesive preparation, smoothing, maturing, curing and type of the shell which are Kevlar and the Cotton fabric were identified as majorly affecting physical and chemical factors to the fluctuation of adhesion in the process line. In experiment I, the accurate amount of secondary solvent (SBP) to adjust the correct viscosity and the TSC of the adhesive was fixed. Same amount of adhesive compound and the primary solvent was blended with six levels of SBP amount (0, 50,100,200,300,400,500 ml) in each sample. Experiment II was carried out to modify the current existing process line with controlling steps and new technical adjustments for increase the adhesion of laminated rubber glove with cotton shell. Number of smoothing term, maturation period and the curing temperature and time period were adjusted in the process line. In experiment III, changing the amount of ingredients of existing formula of adhesive

Proceedings of the Research Symposium of Uva Wellassa University, November 28-29, 2013

to increase bonding ability of laminated rubber glove with Kevlar shell was done and tackifier amount(125g,140g) and the curing temperature and the time period (120,155,160 0Ϲ and 30,40,90 minutes ) were changed. Experiment IV was conducted to introduce a method to reduce the excess moisture content of wasted coagulated centrifuged latex and incorporate recycled rubber as a filler of 20% demand with laminated sheet manufacturing. Three replicates were tested from each sample in each experiment. Finally the manufactured replicates were subjected to mechanical resistance test which are adhesion, tear ,punch abrasion and cut used by tensile tester, Martindale abrasion tester and circular blade cut resistance Tester

Result and Discussion

(anonymous, 2013). Adhesion test was done for all experimental samples and the other tests were done only for experiment IV.Tensile test was done before ageing and after ageing , the rheograph characteristics and moisture content were measured for controlled samples and newly prepared laminated rubber sheet which was incorporated with 20 % recycled rubber. The experiment I, II and IV were designed according to Complete Randomized Design and the iii experiment was done according to two factors Complete Randomized Design and data analyzed by MINITAB statistical software. Significant means of treatments were separated using the Least Significant Difference (P< 0.05) test.

Figure1: Adhesion values of gloves under different Figure2: Adhesion values of gloves under

SBP amount different process lines

According to Figure 1, comparing to the control SBP amount the highest adhesion value (20.3 N) is showed under treatment T4 (200ml of SBP) blend. Comparing to T4 other samples have (T1, T2, T3, T5, T6) low adhesion ability. Comparing to the control sample T4 has a higher TSC (Total Solid Content) value 93.7 and moderate viscosity value 78.7 rpm with the high adhesion. The highest adhesion value due to its special adhesion ability of SBP with optimum viscosity value which leads to correct aqueous nature with easy application potential and highest content of the adhesive matters dissolved in the T4 blend.

In Figure 2, compared to other process lines the glove processed under T16 shows the highest adhesion ability (26.03 N). Figure 2 shows the two smoothing terms, 24 hours maturing period, with 120 0

T9T8T7T6T5T4T3T2T18T17T16T15T14T13T12T11T10T1

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Ϲ and 90 minutes curing characteristic were resulted the highest adhesion value. The smoothing terms cause to improve the mechanical, physical properties and optimum bonds with each other of the rubber sheet and the fabric. The optimum of two smoothing terms creates the even and the smooth surface of both sheet and the shell. It leads to prevent bends, baggy and curled places. Also remove the trapped air between the sheet and the shell and makes barriers to entering the moisture between two layers. The cotton polymer is

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Proceedings of the Research Symposium of Uva Wellassa University, November 28-29, 2013

Figure 3: Adhesion values of gloves under modifying process lines Figure 4: Adhesion, Punch, and Tear, Cut,

Abrasion, Tensile strength Before and After Ageing of gloves

a linear, cellulose polymer. The repeating unit in the cotton polymer is cellobiose which consists of two glucose units (Collar et al .,2012).There are -O-H bonds are donate for make bonds with the adhesive and it is easy to breakdown by supplying a moderate low energy and the considerable maturating period.Other main effect is, it prepares the surface of both rubber sheet and the shell for optimum curing. According to Kevlar shell there are -N-H bonds which are difficult to breakdown. Therefore optimum 24 hours maturation period and the curing are allow preparing the well bonding between rubber and fabric surface. 120 0Ϲ and the curing time is 90 minutes are with low temperature and the long time period. It facilitates the optimum curing and bonding formation between the sheet and the shell. There is a sufficient time period for these formations and less risk with the over curing. And the glove is finished with high quality. The energy consumption is high due to time period.

According to experiment III ,Figure 3 shows the adhesion values of gloves against wood resin and curing temperature and Time. The adhesion ability is highest with the increasing of the wood resin. It is reached to optimum adhesion level with the low temperature and prolonged time period (1200

According to Experiment IV, Figure 4 shows the adhesion, Punch, Tear, cut, abrasion, Tensile strength before ageing, after ageing and moisture content values of control and the incorporated recycled laminated rubber sheet. Though the results of control sample has higher values than the incorporated recycled laminated rubber sheet there is no significant difference (P>0.05) between all resulted properties

of control and the incorporated recycled laminated rubber sheet. According to Table Figure 5, though the control sample has the highest values of each rheograph character, there is no significant different (P>0.05) between the blend and the control sample. Therefore the blend has the approximate vulcanization or cross linking ability regarding to the control sample. Therefore the recycled (dried rubber) rubber has a potential to incorporate with the laminated rubber sheet to fulfill 20% of whole batch as filler.

Ϲ, 90 minutes).Therefore the resin causes to increasing of adhesion ability. The curing temperature and the time period is affected same as in the experiment II.The low temperature and prolonged time period is affect to increase the adhesion when the wood resin content is high.

Figure 5: Rheograph characteristics for control and the incorporated recycled laminated rubber sheet

wood reTemperature

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Proceedings of the Research Symposium of Uva Wellassa University, November 28-29, 2013

Conclusion

The accurate fixed viscosity value 78.7 and the fixed TSC value 93.7 of the adhesive for the highest adhesion ability with 1:2 ratio of adhesive compound and the primary solvent to SBP, the low curing temperature with 120 0

References

Ϲ and the high curing time 90 minutes, two times smoothing times and the 24 hours maturing period and the high amount of wood resin is affects to increase the adhesion ability of the laminated glove. There is a potential to incorporate the dried coagulated centrifuged latex as the cost reduction filler ingredient with the compounding to fulfill the 20% of requirement instant the crepe rubber under the accurate operation conditions.

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