MiniGRAN CONCENTRATES
Granule Size
Resin and color concentrates have historically been produced in two forms,
pellets and granules. Pellets are usually cylindrical in shape and granules
are usually spherical and egg-shaped.
Granule sizes vary in diameter from 1/4" (3mm) to 3/8" (9mm).
In order to get good distribution of a color or additive concentrate,
pellet size of concentrate is usually chosen to match the pellet of natural
resin. This minimizes sifting and separation of pellets in the hopper.
Recently there has been renewed interest in mini or micro pellets/granules.
These are materials in the size range of 0.5-4mm. These materials can
be used with natural materials of similar size (e.g. ground resin powder
or granules) or with conventional pellets.
The advantage of mini-granules are in the improved partitioning in the
hopper of the concentrate. Thus for a 25:1 letdown ratio there is approximately
1 pellet of conventional sized concentrate for every 25 pellets of natural
resin, Figure 1. This contracts with approximately 10 pellets of mini-granules
for every 25 pellets conventional sized resin, Figure 2. Thus for equivalent
formulations the mini-granule should give much better distribution of
color. When using with conventional sized natural resin pellets, the mini-granules
should be approximately 1/10 the size of natural pellet. This allows the
mini-granules to nestle in the spaces between the larger granule, Figure
2.
Figure 1
![Conventional Color Concentrate](../../../../Images/minigranfig1.gif)
Figure 2
![Minigran Concentrate](../../../../Images/minigranfig2.gif)
Pigment Loading
With this new tool, affording better partitioning it is now possible
to increase the pigment loading in the concentrate. Thereby increasing
the letdown ratio from 25:1 to even 100:1. These highly loaded concentrates
sometimes offer economic advantages because of their lower cost of production.
Thus, if one is satisfied with the color reproducibility of their current
masterbatch, highly loaded mini-granules offer a way to decrease costs.
However, if current quality is unsatisfactory due to poor dispersion
or distribution of color or additives, the solution is to stay with your
current letdown ratio and switch to a mini-granule format. This should
improve the color partitioning and uniformity. Thus, industries which
have stayed with precolored compound because they desire very high color
consistency can now consider Mini-Gran Concentrates.
Concentrate Carriers
There has long been a debate over how universal the "universal"
carriers really are. The truth is there are no truly "universal"
carriers. There are however some pretty good "semi-universal"
carriers.
By combining a high pigment loading and therefore a low amount of carrier
with the mini-granule form, one can minimize the side effects of incompatible
resins.
Mini-granules, because of their fine particle size, melt more quickly
than larger conventional sized materials. The mini-granule concentrate
thus melts before the natural pellet, thereby, coating the pellets resin.
As long as the concentrate carrier is not imparting too much slip, it
will give a superior distribution of color.
MiniGRAN Concentrate Sizes
The following are the size codes used to designate our current product:
B |
0.5 mm |
C |
1.0 mm |
F |
4.0 mm |
G |
6.0 mm |
H |
9.0 mm |
FM Group, Inc. offers a variety of concentrates in Mini-Gran form. Colors
and additives are available in a variety of carriers including a number
of "Semi-Universal" (SU) or "Almost Universal" (AU)
systems. We also manufacture conventional and specialty concentrate ,
including Sprincol Texturing Colorants. We welcome your inquires for custom
products.
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Copyright ©2001 Functional Materials
Inc. All rights reserved. Last edited:
08/10/2001
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