- In our dictionary the word "Washing"
means to remove dirt from whatever it
is and this sounds absolutely obvious.
- Well, not that
- For example, most
of everybody calls tanks "washing
- Now you can check
by yourself putting a piece of plastic
into water, and feel free to add even
some soap, leave it there for few hours,
or a day, and see how clean it is after
- It has exactly
the same amount of dirt it was before
this "washing" treatment.
- In other words,
to remove dirt from plastic flakes,
it takes some other action.
- Now, what about
doing what it has been done for centuries
to wash cloths: brushing and/or beating
with stones or something like this,
in other words making friction to remove
- In the 21st century
the way of washing didn't change much,
unless for the fact soaps are different
and performing better.
- The end of the
story is make as much possible friction
(we're speaking about pieces of plastic
and not an expensive piece of cloth)
in presence of something that can trap
dirt into it (detergent).
- Do all plastic
need detergents ?
- Not at all.
- If contamination
is, for example, paper, sand or something
that remains on the surface, detergents
are useless because the process will
be only to remove them from the surface
while, speaking of oil, glue or other
sticky dirt, matter can be different.
- Sometimes, with
some materials, contamination even help
to make polymer to look better; for
example if you leave some PPM of oil
into LD-HDPE or PP you'll get a beautiful
looking pellet, shining, so why to remove
all of it ?
- Or why to remove
all paper contamination if your pellets
will be used to make lumbers ? A little
bit of paper will "expand"
the profile, and nails and screws will
go into much easier than a solid profile.
- Of course we're
talking about a very little amount that
should remain inside the scrap but,
again, sometimes a little bit of contamination
helps to make you product better or
- Most of scraps
anyway, need to be perfectly clean and
here we'll be talking about the meaning
- It needs to perfect
when a certain kind of contamination
really bother being there and needs
to be removed all the way.
- Let's make the
example that, in our opinion, suite
the best this concept: glue
into PET washed bottle flakes.
- Many year ago,
asking to the chief engineer of the
biggest company in the world recycling
PET which was the maximum amount of
glue allowed, he just said: don't know
and don't care.
- So, in the years
we found out the reason for this:
- Glue doesn't effect
PET itself but it just turns the color
of pellets anywhere from yellow to brown
because melting point is a lot different
and glue, normally PU based, release
oxygen to PET and turns it yellow.
- So, if you're
looking for perfectly clear material
or you have to make a precise color
with recycled flakes, you need to remove
all glue content while, for some other
application, you only need a flake with
no dirt and careless about glue content.
- Everybody now
knows how to remove glue while not many
understand how much it does cost.
- And also, after
flakes are gone into any process using
caustic, flakes need a good rinsing
(otherwise your flakes will turn yellow
anyway) adding another cost.
- For the purpose
of washing we did develop our own technology
that is a friction washer where the
amount of friction and residence time
of flakes can be adjusted by the operator.
- The machine is
controlled by a simple electronic device
that keep the amperage of main motor
constant to the level set by operator
and residence time will be accordingly.
- This machine does
not require steam of heater bands of
any kind to make water hot because it
does it by itself, just by the friction
created by the rods spinning inside.
- We have been told
it is too simple to perform well but
we do like simple things. (and