There are close to 2 million
metric tons of super absorbent polymers made
annually in the world.
Most of this volume is used in the personal care markets and in
finished goods
such as disposable baby diapers, feminine care and
adult incontinence products.
Only a very small portion of this total volume is used in the
specialized markets
that
`WaterGel Crystals' (WGc) serves.
pol·y·mer [ˈpäləmər]
NOUN CHEMISTRY
a substance that has a
molecular structure consisting chiefly or entirely of a large number of
similar units bonded
together,
e.g., many synthetic organic materials used as
plastics and resins.
There are close to 2 million metric tons
of super absorbent polymers made annually in the world.
Most of
this volume is used in the personal care markets and in finished goods
such as disposable baby diapers,
feminine care, and adult incontinence
products.
Only a very small portion of this total volume is used in the specialized markets that WaterGel Crystals (WGc) serves.
Our purpose is to identify the best SAPs for these markets and make them
available on an ongoing basis in these
specialty applications.
WaterGel Crystals does this by offering
a broad array of granular superabsorbent polymers that encompass the
most
up-to-date superabsorbent technologies.
These polymers may differ in manufacturing process, chemical make-up,
particle size and shape, absorption speed, retention, gel strength and
more.
The information presented below gives a general overview about the two
basic methods used for making
superabsorbent polymers and how the
processes will affect the different performance aspects of our products.
General Overview of Superabsorbent
Polymer Manufacturing:
A polymer is a substance made up of many (“poly”) repeating units
(“mer”).
The subunits of a polymer are called monomers. Superabsorbent
polymers are made by connecting monomer
units together
to make a long polymer chain that carries an ionic charge (usually
positive or negative…. like the
opposite ends of a magnet) along the
chain itself.
Acrylic acid, and its neutralized form, sodium polyacrylate, are the
monomers used.
However, there are SAPs made with two monomers – acrylic acid and
acrylamide.
These products are called copolymers.
During the manufacturing process, the
long polymer chains are linked together into a three-dimensional
structure using specially designed cross linking agents.
This special polymer structure allows super absorbents to chemically
absorb and retain water-based fluids.
This important feature is what sets super absorbents apart from other
absorbent products – water based
fluids cannot be “squeezed out,” nor
will they “leak out” of the polymer, as the fluid is chemically bonded
within the structure.
Super absorbents can be made in two
ways: through Inverse Suspension Polymerization or via Continuous
Gel
Polymerization.
There are advantages to both systems.
The physical characteristics and performance parameters of polymers are
controlled through the
manufacturing process, although occasionally
post-treatment additives are used to alter or affect
certain desirable
properties.
Inverse Suspension
Polymerization:
In this process, SAPs are produced in batches in large reactors that
produce particles that are perfect spheres.
Under a microscope, these materials will look like bunches of grapes.
Due to their very high surface-to-volume ratio, these SAPs have
exceptional absorption speeds and capacities.
They are also very low dust products.
Such as our Premium Super absorbent snow polymer,
G-70
(Texas Snow©
).
Continuous Gel Polymerization:
(copolymers)
Using this method, SAPs are polymerized on long “poly-belts” that yield
thick mats of polymer that are then
chopped to the correct particle size
and oven dried.
These materials will look like shards of glass under a microscope.
Due to their irregular shape, the absorption speeds and overall
capacities of these polymers are lower than
those that are perfect
spheres; however, the overall gel strength (or performance against
pressure) of these
products is typically higher than their inverse
suspension counterparts.
Our copolymer products,
WHS-2,
40F,
40K, 41K and 42K Polymers,
are made with Continuous Gel Polymerization.