1: How large are EXPANCEL®
microspheres?
2: What are EXPANCEL® microspheres made of?
3: How do EXPANCEL® microspheres work?
4: How can I make EXPANCEL® microspheres expand?
5: What grade/type of EXPANCEL® microsphere is the one that I
need?
6: Can I use EXPANCEL® microspheres even if there is no heating
involved in my process?
7: What types of EXPANCEL® microspheres are available?
8: How can I find out what type of EXPANCEL® microsphere will
be suitable for my product?
9: What type of EXPANCEL® microspheres is used in different systems?
10: Within what temperature range do EXPANCEL® microspheres
expand?
11: Where are EXPANCEL® microspheres produced?
12: What is required of the matrix when EXPANCEL® microspheres
are expanded in-situ?
13: Is it necessary to heat the product if I have added EXPANCEL
WU or DU to it?
14: Can I get technical support from Expancel?
15: In what type and size of packaging are EXPANCEL®
microspheres delivered?
16: Do I need special mixing equipment or special mixing techniques to
add EXPANCEL® microspheres to my product?
17: Can I stop the expansion at some point and later continue the
expansion?
1:
How large are EXPANCEL® microspheres?
A:
Unexpanded EXPANCEL® microspheres (EXPANCEL® WU or DU) have a diameter
between 6 and 40 µm, depending on grade. When unexpanded EXPANCEL® microspheres
are heated they expand to between 20 and 150 µm in diameter.
2: What are EXPANCEL®
microspheres made of?
A: EXPANCEL®
microspheres have two major components, the shell and the blowing agent. The blowing agent
inside the shell is usually isobutane or isopentane. The shell is a copolymer of some
monomers, e.g. vinylidene chloride, acrylonitrile and methylmethacrylate.
3: How do EXPANCEL®
microspheres work?
A: An
unexpanded EXPANCEL® microsphere consists of a thermoplastic shell encapsulating a
hydrocarbon. When this thermoplastic shell is heated it softens and at the same time the
pressure of the hydrocarbon increases. This causes the shell to stretch and expand in much
the same way as a balloon. There is a difference in that when the heat is removed, the
shell stiffens and the microsphere remains in its new expanded form.
4: How can I make EXPANCEL®
microspheres expand?
A: When you
have mixed EXPANCEL® microspheres into your product it´s just a matter of heating
your product to a temperature at which the microspheres start expanding. This can be
anywhere between 100 and 200 °C depending on the grade.
5: What grade/type of EXPANCEL®
microsphere is the one that I need?
A: This
depends on whether or not your product will be heated after the microspheres have been
added, and if so, to which temperature and for how long. It also depends on if your
formulation is waterborne, solvent-based or dry. Is your product subjected to shear forces
or pressure after the addition of EXPANCEL® microspheres? Are there any solvents
present in your product? What is the main property you hope to improve by using EXPANCEL®
microspheres in your product? This question is best answered by our sales staff when you
contact us.
6: Can I use EXPANCEL®
microspheres even if there is no heating involved in my process?
A: Yes, you
would then use the pre-expanded types EXPANCEL® WE or DE.
7: What types of EXPANCEL®
microspheres are available?
A: EXPANCEL®
microspheres are delivered dry or wet (containing water):
EXPANCEL® WU, wet unexpanded
EXPANCEL® DU, dry unexpanded
EXPANCEL® slurry, a dispersion of about 40% microspheres
EXPANCEL® MB, master batch with about 65% microspheres
EXPANCEL® WE, wet expanded
EXPANCEL® DE, dry expanded
8: How can I find out what type of EXPANCEL®
microsphere will be suitable for my product?
A: Contact
us, see this section.
9: What type of EXPANCEL®
is used in different systems?
A: In
general EXPANCEL® WE and WU are used in products where there is already
water present, while DU and DE are used in products that have no water. EXPANCEL®
MB is used in extrusion and injection moulding. WU and DU are used where
the process includes heating, while WE and DE are used in processes that do
not include heating. EXPANCEL® slurry is used in the production of paper and
board.
10: Within what temperature range
do EXPANCEL® microspheres expand?
A: This
depends on the grade of EXPANCEL® microsphere and on the time of heating.
11: Where are EXPANCEL®
microspheres produced?
A: EXPANCEL®
WU, DU, WE, DE, MB and slurry are produced by Expancel at
Stockviksverken, Sundsvall Sweden. EXPANCEL® DE and WE are also produced by
Expancel Inc. in Duluth, Georgia, USA.
12: What is required of the matrix
when EXPANCEL® microspheres are expanded in-situ?
A: The
matrix must be able to flow or be plastically deformed at the temperature at which EXPANCEL®
microspheres start to expand.
13: Is it necessary to heat the
product if I have added EXPANCEL® WU or DU to it?
A: Usually
you have to heat it, but in some cases where there is an exothermic reaction involved, the
energy released by this reaction increases the temperature of the product sufficiently to
expand the microspheres.
14: Can I get technical support
from Expancel?
A: Yes, both
our sales staff and technical staff are there to help you get the most out of EXPANCEL®
microspheres. We can help you choose the proper grade of EXPANCEL® for your
product as well as give advice on equipment for adding EXPANCEL®.
15: In what type and size of
packaging are EXPANCEL® microspheres delivered?
A: EXPANCEL®
WU and DU are delivered in fibre drums containing 50-70 kg, or in Big-Bags,
containing 500 kg.
EXPANCEL® WE is delivered in 10 kg bags and boxes with 10 bags.
EXPANCEL® DE is typically delivered in boxes with four 5 kg bags. There are
variations depending on grade.
EXPANCEL® slurry is delivered in 1.000 litre containers.
EXPANCEL® MB is delivered in 20 kg bags.
16: Do I need special mixing
equipment or special mixing techniques to add EXPANCEL® microspheres to my
product?
A: In
general you can use the same equipment and mixing procedure as you would if you did not
use EXPANCEL® microspheres. When EXPANCEL® WU, DU and slurry is
used, excessive heat must be avoided during mixing because it could cause premature
expansion.
17: Can I stop the expansion at
some point and later continue the expansion?
A: It is
possible to stop and continue expansion several times as long as the matrix is not changed
in any way that would inhibit the expansion of the microspheres.