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Cariflex™ Polyisoprene Latex:
Pure Performance and Comfort
Clean, Versatile Choice
For Dipped Rubber Goods
Cariflex polyisoprene latex (IR latex) offers a
blend of purity, protection and comfort that is
unequalled by natural rubber (NR) latex or other
synthetic rubber. A clean, versatile alternative
to NR latex, it is ideal for the manufacture
of thin-walled products requiring strength
and elasticity.
• Runs like NR latex on existing lines
• Can replace NR latex technology for any
application or process
• Versatile for use in a wide range of processes,
including dipping, heat coagulation, extrusion
of threads, adhesive coatings
• Compatible with typical sterilization methods
With superior softness and elasticity, Cariflex IR latex is
the material of choice for a variety of dipped goods, including
premium surgical gloves that have a comfortable fit and feel.
Natural rubber is a polyisoprene produced by Hevea trees that consists of approximately 99%
cis-1,4 repeating units. Negative qualities of natural rubber, including dark color, odor and adverse
allergic reactions, led to the development of Cariflex synthetic polyisoprene rubber (IR) that closely
resembles NR in molecular structures and in key properties. Cariflex IR latex is produced by using
an initiator to polymerize isoprene monomers. A second step, emulsification of the IR, is required
to produce latex for the manufacture of dipped goods.
Manufacturing Dipped Goods with Cariflex IR Latex
Cariflex polyisoprene latex is a dispersion of 65% isoprene rubber in water. Mirroring key
properties of NR latex, Cariflex IR latex can be processed into dipped goods on existing lines.
Because it contains no organic solvents, Cariflex IR latex can be used without the addition of
extraction systems, recycling loops or explosion-proof equipment. It is versatile in a wide range
of processes, including dipping, heat coagulation and adhesive coatings. It is compatible virtually
everywhere NR latex can be used. Due to very low modulis and elongation values up to 1200%,
dipped goods manufactured from Cariflex IR latex is strong and smooth with exceptional softness
that greatly increases comfort. Cariflex IR latex delivers unmatched purity and consistency.
Cariflex IR latex can be mixed with other synthetic lattices to improve their characteristics, provided
they are anionic or non-ionic stabilized and have a pH in the 9–12 range. In addition, multiple-layer
dipping with different polymer lattices can be used to achieve special product performance.
• Free from naturally occurring natural
rubber proteins that can trigger Type I
allergic reactions
• Contains no ammonia, chlorine or plasticizers
• Delivers strength and protection
• Low elastic modulus results in superior
softness and comfort
• E xtreme purity and consistently high quality
simplifies manufacturing and quality control
Properties of Cariflex Polyisoprene Latex
Compared to Natural Rubber Latex
Latex
CARIFLEX
IR Latex
Natural
Rubber
Total solids content [wt%] 65 Similar
Total rubber content [wt%] 64 Lower
pH 11 Similar
Ammonia [wt%] 0
0.2-0.8
Average particle size [μm] 1.5 0.9
Mechanical stability [sec] ›1500 ›900
Brookfield viscosity [mPa.s] ‹150 Similar
Anionic Polymerization:
The Cariflex™ Products’ Advantage
Cariflex polyisoprene latex derives its inherent purity from our simple and highly efficient
polymerization process. Kraton is the only company in the industry using an anionic
solution polymerization process to produce this type of synthetic polyisoprene rubber.
Our manufacturing standards demand the use of high purity raw materials, and precise
control of manufacturing processes.
Lower Residuals, Higher Purity
The polymerization process employed in the manufacture of IR affects the characteristics
of the finished product, both in solid rubber and latex form. Kraton’s anionic polymerization
process, initiated by alkyl-lithium, has numerous advantages that give Cariflex products their
unique qualities.
• Requires a very small amount of initiator – just a few parts per million
• Results in the near total conversion of isoprene
A synthetic material produced in a precisely
controlled environment, Cariflex IR latex is free
of the impurities and lot-to-lot variations that
are inherent to natural materials. It is shipped
in 200 liter (55 gallon) steel drums or 1050 liter
(275 gallon) IBC tote containers.
• Produces exceptionally pure IR, with very low levels of residual monomer and initiator
• High degree of stability reduces the need for anti-oxidants
• Cariflex IR latex is pasteurized before shipment
Different Polymerization Processes Yield Different Products
Zieger Natta IRcariflex IR
No catalyst
Titanium/Aluminum catalyst
Alkyl-lithium initiator
Branched product
Branched product
Linear products
Wide MWD*
Wide MWD*
High MW, narrow MWD*
98+% cis content
96+% cis content
90+% cis content
High gel content
High gel content
Intrinsically NO gel
Contains natural impurities
Catalyst residuals
Low impurity level
Produced as emulsion
Produced as organic solution
Produced as organic
solution
15
10
0
0
250
500
750
1000
1250
STRAIN %
* MWD: Molecular Weight Distribution, MW: Molecular weight
www.kraton.com
TENSILE STRESS (MPa)
20
Natural Rubber
A typical stress/strain curve of a cured Cariflex polyisoprene latex
sample shows a flat curve up to a strain of about 700%, indicating
that the material is very soft.
U.S.A. Headquarters
Asia Pacific
Europe, Middle East, Africa
Kraton Polymers U.S. LLC
15710 John F. Kennedy Blvd.
Suite 300
Houston, Texas 77032
+1-800-4-KRATON (572866)
info@kraton.com
Rm 1601-03, Plaza 66, Phase 2
1266 West Nanjing Road
Shanghai 200040, China
+86 21 6289 6161
John M. Keynesplein 10
NL – 1066 EP Amsterdam
The Netherlands
+31 (0)20 201 7697
Legal Disclaimer: We believe the information set forth above to be true and accurate, but any recommendations, presentations, statements or suggestions that may be made in the foregoing text are
without any warranty or guarantee whatsoever, and shall establish no legal duty on the part of Kraton Polymers LLC or any of its affiliates. Furthermore, nothing set forth above shall be construed as
a recommendation to use any product in conflict with any existing patent rights. Kraton Polymers LLC expressly disclaims any and all liability for any damages or injuries arising out of any activities
relating in any way to this publication.
Cariflex™ is a trademark of Kraton Polymers. Kraton and the Kraton logo are registered trademarks owned by Kraton Polymers LLC.
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© Kraton Polymers LLC – 2011. All rights reserved.