PIBs - the Performance Chemicals division - BASF.com

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PIBs
Polyisobutylenes are a vital part of adhesive and sealant formulations
By Dr. Timea Marsalko, Business Manager, PIB and Derivatives, BASF Corp., Florham Park, NJ; and
Dr. Margit Hiller, Technical Marketing Manager, PIB and Derivatives, BASF AG, Ludwigshafen, Germany.
BASF has a long history of producing
materials for improving
adhesives and sealants formulations.
BASF acrylates, for instance,
have been widely used in the industry.
This article focuses on the company’s
contributions through the growing
presence of polyisobutylenes (PIBs) in
adhesives and sealants.
PIBs are not new. BASF invented the
materials and has marketed a range of
polyisobutylenes since the late 1930s.
Since then, additional molecular weights
and performance characteristics have
been added to offer new options and new
applications to formulators. The current
portfolio of PIB products includes
low-molecular-weight (trade named
Glissopal), medium-molecular-weight
(trade named Oppanol B 10 SFN –
Oppanol B 15 SFN) and high-molecular-weight
grades (trade named
Oppanol B 30 SF – Oppanol B 200).
Polyisobutylenes are aliphatic polymers
and are widely used in solventbased
or melt-based formulations.
They are an excellent choice of raw
materials for applications that are
moisture sensitive or must be water
insoluble. Depending on the application,
different molecular weight grades
or combinations of several PIB grades
or combinations of PIB and butyl rubber
are used to achieve the properties
of the final products. Generally, lowmolecular-weight
products are used as
tackifiers and/or plasticizers, whereas
medium- and high-molecular-weight
products are used to adjust properties
such as flexibility, elongation, cohesive
strength, and gas barrier performance.
With the correct choice and ratio of
PIB(s), formulators can tailor peel and
tack as well as extend the lifetime of
the finished goods.
Figure 1. BASF PIB Grades
Several different systems are used to
compound adhesives and sealants
using solvent or melt technology.
Polyisobutylenes are often used in noncurable
applications, and in several
cases they can be interchanged with
(replacing) or performance-enhancing
butyl rubber components in butyl systems.
These butyl systems contain polyisobutylene
(completely saturated polymer),
butyl rubber (double bonds in the
molecular chains), or a combination of
both. Butyl rubber is favorable when it
comes to cohesive strength and creep
resistance, whereas polyisobutylene
Reprinted with permission from Adhesives & Sealants Industry magazine, BNP Media

Pressure-sensitive and removable tapes are usually
formulated with the use of one or two different molecular
weight PIBs and butyl or chlorobutyl rubber.
Polyisobutylenes are used to seal joints, to seal
and protect electrical wiring, and to protect
body cavities from moisture.
offers good flexibility, tack, and peel
strength. To adjust the properties of a
formulation to the required end use,
combinations of both polymer types are
often used.
Although PIBs do not have more than
one double bond per polymer chain, they
are considered to be non-crosslinkable
products by conventional crosslinking
chemistry (sulphur or peroxide cure).
There are, however, several special
crosslinking modes in which PIBs could
become crosslinkable, such as via radiation
curing.
Polyisobutylenes have better aging
characteristics than rubber-based (especially
natural rubber-based) systems. PIBbased
products remain permanently
tacky and are used on surfaces other
polymers do not adhere to.
TYPICAL APPLICATIONS
The window sealant industry in Europe,
governed by higher energy standards, is
dominated by double-glazing window
sealants. PIB is the base polymer and the
main component in these formulations.
In these sealant systems, mainly Oppanol
B 15 or mixtures of Oppanol B 15 and
Oppanol B 10 are formulated. Oppanol is
primarily used because it has excellent
barrier properties and excellent flexibility,
even at low temperatures.
Furthermore, it is able to seal hermetically,
due to its tackiness and cold flow,
to even rough glass surfaces.
New systems emerging on the market
called TPS ® (thermoplastic spacer) systems
contain PIB. Butyl tape sealants
contain a mixture of high- and mediummolecular-weight
PIBs to achieve the
Table. PIB Property Profile for Outstanding Product Features
(Property profile is unique in the segments of adhesives and sealants)F
• Excellent barrier to moisture and gas
• Elasticity over a wide temperature range – even at low temperatures
• Permanent tackiness
• Excellent aging characteristics
• Cold flow for self healing materials and hermetic sealing of rough surfaces
• High up-take of fillers
• Odorless and colorless for superior aesthetics
• PIB is a non-curable polymer - except by radiation curing - and certain grades
of the MW range are very viscous and have high damping properties.
right combination of strength and tackiness.
In general, butyl-based sealants are
processed as pliable-tape or as a hot-melt
system. They can be used in joints with
movement of up to 10-15%.
PIB-based sealants are also used in
several non-window applications.
Commercial pipes in underground or
underwater locations can be protected
against the corrosive nature of the
environment. Those pipes are wrapped
with adhesives tapes that usually contain
polyisobutylenes.
Underwater cables are filled with PIB
for two main reasons: to provide selfhealing
properties and to combat potential
punctures, and to keep moisture
away from the optical fibers.
Higher molecular weight polyisobutylenes
are also used in roofing
membranes. One notable application is a
technology imported from Europe. These
roofing membranes are primarily used in
commercial roofing and protect the
structures from rain and melting snow by
providing moisture sealing.
From manufacturing to transports to the
dealer, today's automobiles are protected by
using a composite polymer layer containing
PIBs. In a variety of important automotive
sealant applications, polyisobutylenes are
used to seal joints, to seal and protect electrical
wiring, and to protect body cavities
from moisture.
The seals in food cans and jars could
contain PIBs, which provide an excellent
Reprinted with permission from Adhesives & Sealants Industry magazine, BNP Media

JUST ADD PIBS
gas and moisture barrier. They are inert
and clean, fulfilling a variety of FDA
food contact requirements.
Adhesives generally cover a large variety
of chemistry and technology bases.
Polyisobutylenes are used in many
adhesive formulations due to their tackiness,
flexibility and low cohesive
strength. PIB is used in adhesive systems
— mainly pressure-sensitive and hotmelt
adhesives.
Pressure-sensitive and removable tapes
are usually formulated with the use of one or
two different molecular weight PIBs and
butyl or chlorobutyl rubber. Medium-molecular-weight
PIBs are great for adhering to
the surface. The high-molecular-weight version
is preferred when the finished article is
die cut or when the formulation is extruded
during processing.
PIBs are not a skin irritant and BASF
PIBs have a very low level of impurities.
Therefore, PIB-based adhesives that
require human contact, such as woundcare
products or ostomy devices, are usually
based on PIBs.
For more information on polyisobutylenes, visit
www.basf.com/pib_derivatives.
PIB is used in adhesive systems — mainly
pressure-sensitive and hot-melt
adhesives.
INFORMATION
General Information:
www.basf.com/pib_derivatives
oppanol@basf.com
Business Management Europe:
Dr. Erwin Czech
+49-621-60-71180 or
erwin.czech@basf-ag.de
BASF AG
Unit: EVO/EP
Building J550
Carl-Bosch-Strasse 38
D-67056 Ludwigshafen
Germany
Business Management NAFTA:
Dr. Timea Marsalko
+1-973-245-6175 or marsalt@basf.com
BASF Corporation
Unit: N-EVO/N
100 Campus Drive
Florham Park, NJ 07932
USA
Business Management Asia:
Mr. Michael-e Hu
+65-6432-3405 or
huem@basf-sea.com.sg
BASF South East Asia
Unit: A-EVO/A
7 Temasek Boulevard
35-01 Suntec Tower One
038987 Singapore
Singapore
Business Management South America:
Ms. Gisele Regina Dos Santos
+55-11-4343-3119 or
gisele.santos@basf-sa.com.br
BASF SA
Unit: S-EV/SD
Building C
Estrada Samuel Aizemberg 1707
09851550 BASF - Imigrantes
Brazil, Region SP
Business Management East Europe, Africa,
Middle East, etc.:
Mr. Gerhard Leidig
+49-621-60-76552 or
gerhard.leidig@basf-ag.de
BASF AG
Unit: EUM/SE
Building: LU-Benckiserplatz
Benckiserplatz 1
D-67056 Ludwigshafen
Germany
Technical & Strategic Marketing (Adhesives
& Sealants):
Dr. Margit Hiller
+49-621-60-47498 or
margit.hiller@basf-ag.de
BASF AG
Unit: G-EVO/MP
Building: J 550
Carl-Bosch-Strasse 38
D-67056 Ludwigshafen
Germany
Reprinted with permission from Adhesives & Sealants Industry magazine, BNP Media