The document discusses improving adhesion in laminated rubber glove production through modifying process parameters and incorporating recycled latex. Key findings include: (1) Optimal adhesive viscosity and solid content improved adhesion; (2) Increased wood resin and modified curing enhanced bonding; (3) Recycled latex incorporation showed no significant impact on quality. The study optimized laminated glove production for improved adhesion and lower costs.

1. Improving of Adhesion in Laminated
Rubber Glove Process and
Incorporation of Recycled Coagulated
Centrifuged Latex
R.G.N Lakmali
UWU/PLT/09/0020
Palm and Latex Technology and Value Addition
Uva Wellassa University

2. Introduction
Natural Rubber Latex is the major synthesized
commercial product by the rubber (Hevea brasilie
nsis) tree
Production of NR 2011(Actual) to 2014(forecast) (‘000
tonnes)
Source: International Rubber Study Group ( IRSG )
Region 2011 2012 2013 2014
Asia 10281 10659 10986 11628
Africa 470 491 518 548
Latin America 48 48 50 52
World 11004 11406 11771 12453

3. Natural rubber based products
-Dry rubber products
eg: Laminated gloves,Tyre, Caster wheels
-Latex products
eg: balloons, surgical gloves, cast products
What is a Laminated glove?
It is coming under household category use for heavy duty
purposes and for construction industry which is made by
using a laminated rubber sheet as a composite to palm
area with textile fabrics(Kevlar ,Cotton)

5. Problem Identification
Low adhesion property of laminated gloves
-reducing of other mechanical properties (abrasion ,
tear, punch, cut)
- lower the quality and the demand in the
international market
High moisture content of coagulated centrifuged latex
-unable to direct incorporate with laminated rubber
sheet process
- large wastage avoiding recycling with high cost

6. Main Objective
Enhance the adhesion ability between the laminated
rubber sheet and two types of fabrics, Kevlar and Cotton
 Introducing of new recycle method to reduce the
moisture content coagulated centrifuged latex

7. Specific Objectives
Fix the accurate amount of secondary solvent (SBP) to
adjust the correct viscosity and the TSC of the adhesive
 Modify the current existing process line with controlling
steps and new technical adjustments
Change the amount of ingredients of existing formula of
adhesive
Check the potential of incorporation of recycled rubber
as a filler to fulfill 20% of requirement

8. Materials and Methods
Basic Ingredients
 Crepe rubber
Compounding materials
(Chemicals)
 Fabric (Kevlar, Cotton)
 Coagulated centrifuged
latex
Machines
Two roll mill ,Mixing
machine
Calendaring roll
Bale cutter
Drying machine
, Oven, Autoclave
Brook field Viscometer
Tensile Tester
Hardness testing machine
Cut resistance machine
Digital weighting Machine

9. Preliminary Experiment
Identification of mostly affecting process steps and factors
for adhesion ability by observation
•The adhesive preparation
•Smoothing
•Maturing
•curing Conditions( temperature, time)
•type of the fabric (Kevlar , the Cotton

10. Crepe
Fabric
Coating
Drying
Sticking
Curing
Glove
Milling
Calendaring
Adhesive
Smoothing
Maturing
Laminated Rubber Glove Process

11. Experiment 1:Fix the accurate amount of secondary solvent
(SBP) to adjust the correct viscosity and the TSC(Total Solid
Content) of the adhesive
Complete Randomized Design(CRD)
Necessary SBP Amount to the Blend
1
sample
2
sample
3
sample
4
sample
5
sample
6
sample
Adhesive compound
+ Primary solvent(ml)
100 100 100 100 100 100
SBP volume(ml) 0 50 100 200 300 400
Treatment Name T1 T2 T3 T4 T5 T6

12. Experiment 2: Modify the Current Existing Process
Line with Controlling Steps and New Technical
Adjustments
Smoothing
turns
Maturing
period(hours)
Curing temperature
and Time
Sample
number
Adhesion
Value
0Ϲ Minute
One turn Just after
unloading
from former
155 40 3
160 30 10
120 90 11
24 155 40 5
160 30 6
120 90 7
48 155 40 2
160 30 8
120 90 9

13. Smoothing
turns
Maturing
period(hours)
Curing temperature
and Time
Sample
number
Adhesion
Value
0Ϲ Minute
Two turn Just after
unloading
from former
155 40 1
160 30 13
120 90 12
24 155 40 14
160 30 15
120 90 16
48 155 40 4
160 30 17
120 90 18
Modified Steps of process lines
CRD method

14. Experiment 3: Changing the Amount(parts) of Ingredients
of Existing Formula of Adhesive
Two Factors Factorial CRD method
Ingredients Former amount Changed amount Examples
Raw Rubber 0.5 same Crepe rubber
Activator 0.025 same Zinc Oxide
Accelerator, Scorch Resistance 0.007 same M.B.T.S
Dispersing agent, plasticizer 0.006 same Stearic acid
Accelerator 0.001 same T.M.T.D
Lubricant 0.005 same
Coupling agent 0.01 same
Tackifier 0.125 0.140 Wood Resin
lubricant, softening agent 0.0125 Same Petroleum jelly
Cross linking agent 0.008 Same Sulphur

15. Experiment 4
Reduce the moisture content of
coagulated centrifuged latex
CRD method
Coagulated
centrifuged latex(5kg)
Drying(sun drying
- 4 days, 1.5 days
, near autoclave )
Laminated sheet
Partition
Milling with
batch
Measuring
moisture content

16. For experiment I, II, III and IV – Adhesion test
For experiment IV - mechanical tests (abrasion , tear,
punch, cut)
-Tensile test(After and before ageing)
-Rheograph
-Moisture content
Minitab statistical software was used to analyze the data

17. Results and Discussion

18. Experiment 01:Adhesion of laminated gloves
0
5
10
15
20
25
T0 T1 T2 T3 T4 T5 T6
Mean adhesion(N)
T0
T1
T2
T3
T4
T5
T6
Treatment Name
Adhesion(Newton)

19. Experiment 01:Adhesion of
laminated gloves Treatment Name Mean ± SD
T0 11.983±1.535BC
T1 18.95±3.73AB
T2 14.97±1.90ABC
T3 12.48±1.44BC
T4 20.613±0.757A
T5 11.16±2.64C
T6 15.40±4.02ABC
Value with the different
letter as superscripts is
significantly different at the
level of 5%. Results are
present as mean ± SD

20. Ratio of amount of
Adhesive compound and
Primary solvent to SBP - 1:2
Viscosity and TSC values for each adhesion level of
adhesive
Mean Value
Treatment
Name
T0(co
ntrol)
T1 T2 T3 T4 T5 T6
Viscosity(r
pm)
10.5 100 100 100 78.7 20.3 0.3
TSC 86 70.7 88.7 90.3 93.7 96.3 96

21. Experiment 02:adhesion under modified process
lines
0
5
10
15
20
25
30
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 T17 T18
Mean Adhesion T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
T13
T14
T15
T16
T17
T18
Treatment Name
Adhesion(Newton)

22. Value with the
different letter as
superscripts is
significantly different
at the level of 5%.
Results are present as
mean ± SD
Treatment Mean ± SD Treatment Mean ± SD
T1 8.26±0.551E T10 14.89±1.649BC
T2 11.067 ±1.67CDE T11 15.95±1.64B
T3 9.110±0.721DE T12 10.73± 0.643CDE
T4 6.653 ±1.166E T13 17.10± 1.637B
T5 14.417±0.52BC T14 14.37±2.97BC
T6 13.493±0.50BCD T15 10.89±0.185CDE
T7 9.800±0.346DE T16 26.03± 3.19A
T8 17.36± 0.651B T17 10.55±1.91CDE
T9 16.90±0.954B T18 14.50±0.436BC

23. T16 Process line
Two smoothing turns- creates the even and the smooth
surface ,prevent bends, remove the trapped air and barrier
to entering the moisture
24 hour maturing period- Optimum chemical reactions
and bonding formation
Curing Conditions (120 0Ϲ,90 minutes) - optimum curing
and bonding formation
Smoothing
Two Turns
24 hour
Maturing
period
Curing ,120
0Ϲ,90 minutes

24. Fabric
Laminatedsheet
Coating
Adhesive

25. Experiment 03-Adhesion under changed wood
resin amount and curing conditions

26. Adhesion of gloves against wood resin and changed
curing temperature and Time
Value on the same line with the same letter as
superscripts is not significantly different at the level of 5%.
Results are present as mean ± SD
Temperature 0Ϲ/Time (minutes)
Wood Resin(g) 1200Ϲ /90min 1550Ϲ /40min 1600Ϲ/30min
125 11.3±0.93B 8.1±1.183 B 8.8±1.240 B
140 23.5±3.35 A 11.9±0.907B 9.6±1.303B

27. Wood Resin- Common raw material to increasing of
adhesion ability

28. Experiment 04 - Comparison of Adhesion , Punch , Tear
, Cut , Abrasion, Tensile strength Before Ageing and After
Ageing , Moisture content and Rheograph Characteristics
of controlled and blend sample
0
2
4
6
8
10
12
14
16
Control
Blend
0
10
20
30
40
50
60
70
Maximum Torque Scorch Time T 90
Control
Blend

29. P values for relevant tests
Moisture content- 0.8554
Mechanical Testing
 Abrasion(levels) - 0.957
 Cut(levels) - 0.685
 Tear(levels) - 0.988
 Punch(levels)- 0.653
 Tensile Strength (Before
ageing) MPa- 0.6359
 Tensile Strength(After ageing)
Mpa - 0.216
Rheograph Characteristics
 Maximum Torque(Lb-in)-0.1843
 Scorch Time (Minutes)-0.632
 T90 (Minutes)-0.156
• There is no significant difference
between the control and the
blend at the level of 5%
• The blend with recycled rubber
suitable as the filler ingredient

30. Conclusion
The accurate viscosity and TSC values which are
78.7rpm and 93.7 of the adhesive with the 1:2 ratio of
solvents , the high amount of wood resin with low
curing temperature with 120 0Ϲ and the high curing
time 90 minutes, two times smoothing times and the
24 hours maturing period are majorly affect for the
highest value of the adhesion

31. There is a potential to incorporate the recycled 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

32. Limitations
Uneven application of the adhesive on the laminated
sheet
Excessive stock /deficiency of stock cause to change the
maturing period
More time taken with drying of coagulated centrifuged
latex

33. Recommendations
Punctually measuring of viscosity and TSC of the
adhesive and following of modified process line with
recommended wood resin content
Recycle of coagulated centrifuged latex as a cost
reduction process
Reducing of drying time with Proper oven system of
coagulated centrifuged latex

34. References
Martin,J.M,(M.Sc,Ph.D,C.Eng),Smith W.K,(C.Eng),Handbook of Rubber
Technology. Volume 03, Identification ,Testing, Recycling and Pollution
Control in Rubber Industry,ed.by Bhatia,C.S. (B.E(Chemical)
,M.B.A),PUBLISHERS AND DISTRIBUTERS,NEW DELHI,BANGALORE
White J.L, Rubber Processing Technology. Materials and
Principles,Hanser Publishers, Munich Vienne New York, Hanser/Gender
Publications,Inc,Cincinati
Freakley P.K, Rubber Process and Production Organization, Institute of
Polymer Technology, Southborough University of
Technology, Loughborough,United Kingdom, Plenum Press, New York and
London
Polaski G, Means J, Stull B, Warren P, Allen K, Mowrey D, and Carney
B,Bonding Elastomers: A Review of Adhesives and Processes, (Lord
Corporation)

35. Acknowledgement
Dr. G . Chandresena, Dean , Faculty of Animal Science and
Export Agriculture
Dr. Saman Herath, Faculty of Animal Science and Export
Agriculture
Mr.Thameera Ranasinghe,External Supervisor, Manager
Technical,Workwear Lanka(Pvt) Ltd
Ms. H.A.S.L Jayasinghe,Internal Supervisor, Faculty of Animal
Science and Export Agriculture
Dr. Susantha Siriwardhene,Head of Dry Rubber Department
, Rubber Research Institute ,Rathmalana