Products
Ficel:
General Properties Dust-free handling
Powder blowing agents can cause dusting and be difficult to handle
or meter efficiently at the typical loadings of less than 1 %. The
FICEL® liquid and pellet forms help to assist in convenient and dust-free
handling without the need for personal respiratory protection or expensive
dust extraction equipment. Furthermore, the pellet masterbatch product
can be added and dispersed with the polymer by tumble blending or
direct metering on standard equipment. The liquid forms can be added
directly to the extruder feeder, or readily mixed into a vinyl plastisol.
All of these benefits help to improve the working environment and
minimize the capital investment for the safe and effective use of
these products
.
Faster dispersion
FICEL® liquids and pellets can be dispersed faster than equivalent
powder blowing agents. This can lead to a significant reduction in
the blending times and costs required to achieve uniform dispersion
of the blowing agent throughout the polymer. The use of FICEL® pellets
may eliminate the need for additional agents (e.g. paraffinic oil)
to incorporate low concentrations of powder blowing agents. It also
reduces the incidence of "screw slippage" when high levels
of powder blowing agent and processing agent are used.
Proven performance
The superior quality and performance of FICEL® blowing agents has
been proven by many years of commercial use in a wide variety of very
demanding applications. The density of extrusions and plastisols can
be reduced by more than 50%, which can significantly reduce the unit
costs of production.
General Use Information
Addition levels of these products will vary according to the density
of the foam required and the gas yield of the particular blowing agent.
The gas yield of the blowing agent is a function of the amount of
active blowing agent in the product (activators and carriers generally
do not produce gas), and the type of blowing agent. A typical non-filled
rubber has a specific gravity of 1.2 g/cc. To reduce the density of
100 g of this polymer by 50% (a sp gr of 0.6 g/cc) 100 ml of gas must
be captured in the polymer melt. To calculate a starting-point level
of the Parts of CBA/part of Polymer needed, use the formula:
Parts of CBA = [1/desired foam sp gr - 1/polymer sp gr] / gas yield
of CBA
Example: 0.00325 g of azodicarbonamide (gas yield 220 cc/g) reduces
the density of 1 g of rubber (sp gr 1.2) to a density of 0.6 g/cc.
(For conversion to English units 1.0 g/cc = 62.4 pcf, pounds per cubic
foot.)
The melt strength of the polymer and formulation play a critical
role in determining the amount of gas that can be contained by the
melt without rupturing the foam cells. Various blowing agent types
produce different gases (for example nitrogen from azodicarbonamide),
and in turn the different gases are more or less soluble in a particular
polymer melt. It is desired that the solubility of the gas be such
that it does not migrate rapidly through the melt to escape at the
surface. Thus the density achieved depends on how much gas is delivered
by the chemical blowing agent, as well as how much of that gas is
retained in the polymer melt, this is generally referred to as the
gas containment limit (GCL). This property value is dependant on the
melt strength of the cell wall.
FICEL® products can be used at processing temperatures of 325 to 380
°F depending upon the product and processing equipment. The addition
levels of these products will vary according to the density of the
foam required and is typically:
0.25 % for powders, to 1.5 % for pellets
FICEL® pellets can be dispersed easily by tumble blending with the
PVC pellet compound on standard equipment and adding the blend to
the machine hopper for the processing, or volumetric or gravimetric
feeders can be used. The FICEL® liquids can be directly metered into
the extruder by positive displacement pump.