General Purpose Standard Malaysian Rubber

1. GENERAL PURPOSES
NATURAL RUBBER (SMR GP)
PRODUCTION
PST 161
UNIVERSITI TEKNOLOGI MARA
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2. DEFINITION
• SMR GP, general purposes natural rubber
is the major material for tire production.
• Made from 60:40 mixture of latex-grade
sheet rubber and field coagulum.
• Prepared from:
blend of latex rubber,
unsmoked sheet rubber,
field coagulum rubber and
plasticizer.
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3. IMPORTANCE OF SMR GP
PRODUCTION
• Dark colored rubber
Make it suitable for tire production.
• Blending of latex and sheet rubber
ensure high quality of SMR GP.
• Uses of plasticizer in SMR GP gives
beneficial to tire manufacturers.
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4. GENERAL PROPERTIES
• Contains blending of latex
rubber, unsmoked sheet rubber, field
coagulum rubber and plasticizer.
• The properties of this materials are
by following proportions:
– 30% weight of latex rubber
– 30% weight of sheet rubber
– 30% weight of coagulum rubber
– 10% weight of rubber plasticizer
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5. • There are two types of SMR GP which
have different composition from one
another:
– SMR GP 1
– SMR GP 2
Weight (%)
Raw materials
SMR GP 1 SMR GP 2
Field latex 60 30
Rubber coagulum 40 40
Unsmoked sheet
rubber - 30
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6. PROCESS FLOW OF SMR GP
• Production of SMR GP involves the
method of blending which is involving co-
coagulation of latex-oil mixture and wet
crumbs.
• Wet crumbs use prepared from a blend of
unsmoked sheet and field coagulum.
• Subsequent processing gives:
– Very uniform blend
– Minimum mechanical working
• The process flow are presented
below:
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8. • The process above involving the following
steps:
1. Field coagulum is pre- cleaned and then
formed into a blanket.
– depends on the quality of raw material
and should give a blanket with less than
0.12% wt. dirt.
2. The unsmoked sheets are milled into a
blanket.
3. The unsmoked sheet and field coagulum
blankets are blended
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9. 4. The crumbs are transferred and spread
evenly into a latex coagulation tank, then
manually sprayed with 10% formic acid
solution.
5. required amount of emulsified aromatic
oil and then mixed into a pre- determined
quantity of latex.
– Hydroxylamine Neutral Sulphate is
added to the latex as viscosity stabilizer.
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10. 6. The latex- oil mixture is adjusted to pH 7.0
to 7.5 and poured into the coagulation
tank.
7. Latex-crumb coagulum then processed
and dried.
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