HAND PROCESSING CROSSLINK
POLYURETHANE PRODUCTS
Polyurethane compounds developed by Crosslink technology Inc. can
be easily processed by hand, without the necessity of automated equipment. Many
of these urethane systems are suitable for processing at room temperature due to
their low inherent viscosities. The following are typical processing
instructions covering two and three component urethane systems:
HAND BATCHING
THREE COMPONENT
VARIABLE HARDNESS POLYURETHANE™
CLV 1V-019-A/B/C
(Patent
Pending)
CROSSLINK® Three Component Variable Hardness
System is designed for hand batching according to the following procedure:
There is no need to warm Part-A, B or C, as all
components are low viscosity liquids at room temperature. We recommend that all
mixing should be carried out at room temperature.
-
Pre-weigh and mix Part-A and B according to the recommended mix ratios (by
weight) in a plastic or metal container at room temperature. Any additives
such as pigments and fillers if required should be added to the mix at this
point.
-
Place
the sample in a vacuum chamber and adjust the vacuum to minimum of 29 in. of
Mercury. Degassing should continue until most of the bubbling has ceased.
De-gassing of Part-A and B should not take more than 5 min.
-
While
Part-A and B are degassing, weigh out the correct amount of Part-C in a
container at room temp. Degas Part-C at RT. If necessary, degassing aid
(Sag-47) can be added to part-C to speed up degassing process.
-
Add the
Part-C to pre mixed Part-A and B. Mix thoroughly with out whipping too much
air into the mix. Make sure that the walls and the bottom of the container are
being scraped during mixing. There should be no swirls visible and the mixture
should be completely homogeneous.
-
Place
the mixture back into vacuum chamber and degas until most of the air that was
mixed-in is gone. This usually takes no more than 5 minutes. A good rule of
thumb is when the surface of the mixture is more than half clear of bubbles
under good vacuum, degassing is usually adequate. Pour times of less than 5
minutes usually do not allow degassing after mixing.
-
Pour
the mixture into a preheated mold that has been sprayed or coated with mould
release. The temperature of the mould should determine the de-mould time for
the cast part. The processors should determine their own mould temperature. It
could be anywhere between 60°C to 100°C. Higher the mould temperature shorter
the de-mould time. In most cases cured part can be de-moulded in minutes.
However, keep in mind that the longer the gel time, the longer the de-mould
time.
-
Recommended post cure time: 4 hrs. @ 100°C.
or 6-8 hrs @ 800C
or 66 hrs @ 600C
or 7 days @ 250C
The preceding steps are meant to be a guide for hand
batching Crosslink Urethane Systems. After becoming familiar with this
technology, it will become apparent that steps may be shortened or eliminated.
Call Crosslink® Technical Service at 1-800-563-3769 for more
information.
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HANDBATCHING
Crosslink®
Two Part Polyurethane Systems:
CROSSLINK® systems are designed for hand batching
according to the following procedure:
There is no need to warm Part-A or B as both the
resin and the Polyol Curatives are low viscosity liquids at room temperature. We
recommend that all mixing should be carried out at room temperature.
-
Pre-weigh Part-A according to the recommended mix ratios (by weight) in a
plastic or metal container at room temperature. Any additives such as pigments
and fillers should be added to part-A at this point.
-
Place
the sample in a vacuum chamber and adjust the vacuum to minimum of 29 in. of
Mercury. Degassing should continue until most of the bubbling has ceased.
De-gassing of Part-A should not take more than 5 min.
-
While
Part-A is degassing, weigh out the correct amount of Part-B in a container at
room temp. Degas Part-B at RT. Degassing aid (Sag-47) can be added to part-B
to speed up degassing process.
-
Add the
Part-B to Part-A and mix thoroughly without whipping too much air in to the
mix. Make sure that the walls and the bottom of the container are scraped
during mixing and there should be no swirls visible. The mixture should be
completely homogeneous.
-
Place
the mixture back into vacuum chamber and degas until most of the air that was
mixed-in is gone. This usually takes no more than 5 minutes. There is enough
time for degassing for most of our systems. A good rule of thumb is when the
surface of the mixture is more than half clear of bubbles under good vacuum,
degassing is usually adequate.
-
Pour
the mixture into a preheated mold that has been sprayed or coated with mould
release. The temperature of the mould should determine the de-mould time for
the cast part. The processors should determine their own mould temperature. It
could be anywhere between 60°C to 100°C. Higher the mould temperature shorter
the de-mould time. In most cases cured part can be de-moulded in minutes.
However, keep in mind that the longer the gel time, the longer the de-mould
time.
-
Recommended post cure time: 4 hrs. @ 100°C.
or 6-8
hrs. @ 80°C.
or 16 hrs. @ 60°C.
or 7 days @ RT.
The preceding steps are meant to be a guide for hand
batching Crosslink Urethane Systems. After becoming familiar with this
technology, it will become apparent that steps may be shortened or eliminated.
Call Crosslink® Technical Service at 1-800-563-3769
for more information.
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