(Soft Polymer for
Concrete Mold Making, Gaskets, Grip Parts)
MPP-A25E is room
temperature curable polyurethane casting resin system formulated to
meet typical requirements for concrete mold making application.
The mixing ratio is set to be 1:2 by volume for simple manual
metering. Relatively, low viscosity values of the component
materials help copying the fine mold surface resolution. The long
pot-life and gradual curing pattern gives more working-time/
open-time for a manual mixing/casting operation.
consistency and high elongation value help demolding concrete parts
with deep-cuts and under-cuts. Its good tensile strength and tear
strength help the longevity of the molds made of this material.
The cured material is
hydrophobic. This helps the longevity of concrete molds made from
this material. Also, this set of properties makes this material a
good candidate for the raw materials to make gaskets, grip parts for
tools, and many other custom applications.
Component: MPE-046 (Prepolymer)
Component: PPE-089 (Curative)
100: 200 = Part-A: Part-B by Volume
(100: 191 by
Ambient (72 – 82 ˚F)
Ambient (72 – 82 ˚F)
72 – 100 ˚F
15 – 18 minutes at room temperature
6 to 8 hours at ambient room temperature
continues to cure and hardens at room temperature for the next 3
to 5 days to reach the final physical properties.
The curing patterns are tested at ½” thick sample in resin mold
(polyurethane mold) at 77 ˚F. Thinner segments may take longer
to cure. Lower mold temperature can cause the material to cure
slowly or not cure properly. Auxiliary heating may be required
if thin parts are not curing properly.
(Typical Values Based on Lab Tests)
Durometer) 25 – 30 A
Strength 389 psi
Elongation 995 %
Strength 90 pli
Strength 27 pli
Rebound 51 %
Viscosity 1,650 cps at 77 ˚F
(Part-A) Curing Agent (Part-B)
2000 cps 1000 cps
Sensitivity of Part-A Component
Part-A component (MPE-046) is cold-temperature sensitive. If it is
kept in a cold place for a long time, crystal is formed and depletes
the functional chemical within part-A. Especially, if the material
is frozen, the crystal formation rate is very fast. In the coldest
part of winter, it may freeze during the transportation. If it is
frozen, it must be thawed quickly by heating the material to 140 –
160 ˚F. MPE-046 should be stored in a warm place in the temperature
range 72 – 100 ˚F. The shelf life of these component materials are
Brief Safety Outline
When you are handling
these component materials, please operate in a wide area with good
air circulation or well-ventilated area. Please wear rubber gloves,
long sleeves, and protective eyewear (paint goggle etc.) to avoid
skin/eye contact of the materials. Please read the Safety Data
Sheets for the details on safety, handling, storage, and processing
Low Shrinkage Formula
When producing resin molds, shrinkage of resin is a critical
aspect. The temperature, at which material turns to solid, plays
the most important role. When a typical resin material is hot, it
takes larger volume than when it is cooler. So if resin cures at a
higher temperature, it shrinks more when it cools down.
Polyurethane resins cures with exothermic heat, which means heat
created from the chemical reaction. This formula is specially
design to minimize shrinkage by making the chemical reactions taking
place more gradually. The chart below shows the temperature
increase between the time part-A and part-B are mixed and the
material is too thick to pour.
5-gallon pails (40 LBS per pail)
55-gallon drums (450 LBS per drum)
Pail Kit (21 LBS of part-A in 1 pail and 40 LBS of part-B in 1
pail; 61 LBS total in 2 pails)
Drum Kit (236 LBS of part-A in 1 drum and 450 LBS of part-B in 1
drum; 686 LBS total in 2 drums)
Storage/Handling Information for the Component Materials
(Isocyanate Prepolymer) Component
component (prepolymer) contains isocyanate component, which is
highly sensitive to moisture. If it is left in air, part-A will
react with atmospheric moisture and will be ruined. This reaction
is non-reversible. Soon after opening the container to dispense the
content, dry nitrogen gas or argon gas needs to be injected to the
container to purge and blanket the top space. Please consult
Northstar Polymers for nitrogen gas set-up information.
feeding system from a 55-gallon, silica gel or calcium chloride
desiccant filter(s) should be installed to the vent-hole of the
drum. A valve to inject dry nitrogen gas can be installed instead.
material has been tested for the stability at 32 ºF for a few days.
However, when the outdoor temperature is below 32 ºF during
transportation, there is a chance of freezing. The frozen material
must be immediately thawed to avoid permanent damage from freezing.
If the material color is opaque with the consistency of thick
liquid, gel, waxy, or solid, the material requires immediate
thawing. The container should be put into an industrial oven at 180
ºF until the material temperature is 140 ºF or the color of the
material is clear with smooth liquid consistency. Storing frozen
material more than a few days will cause a permanent damage to the
material, and it will not be returnable or refundable.
containers a dry indoor storage within the temperature range between
77 and 100 ºF. The ideal storage temperature is 90 ºF. Avoid direct
prepolymer used for this formulation contains different isocyanate
isomers with different freezing points. When the product is shipped
in cold season, the isocyanate isomers and extended prepolymer may
separate into layers in the container. During the cold season, the
container must be heated to about 150 ˚F and agitated to ensure
homogeneous blend before use. The material should stay as viscous
liquid at room temperature. To avoid separation during the storage,
store it in between 77 ˚F and 90 ˚F storage temperature range.
If a large
amount of water mixes with a large amount of isocyanate base
materials, the chemical reaction may produce a large amount of CO2
gas and heat to create a hazardous condition. Keep the storage area
free of water.
certain combination of heat, catalyst (basic chemicals), amounts of
reactive materials, and some other favorable conditions for the
reaction, the water (or alcohol/glycol/amine) to isocyanate reaction
can reach a dangerous state of accelerated reaction. The
accelerated reaction may create a very high temperature condition.
The thermal decomposition of isocyanate based material by extremely
high temperature or fire can produce toxic gasses and smokes. Please
be sure that the containers are stored in dry indoor storage, away
from source of large amount of water.
If a leak
is found in a drum, please place the drum in such a position that
the leaking part is at the highest part of drum so that the content
no longer leaks out. Cover the leaking area with dry towel to
prevent air from entering. If possible, transfer the material into
new container(s) with nitrogen purge. If moisture enters into an
isocyanate container from a small leakage, CO2 gas may be produced
to gradually pressurize the container. If pressure built up is
suspected, open the bung (or cap) very slowly to release the
pressure before you change the drum position.
component is hygroscopic. If the material is exposed to ambient
air, it absorbs moisture. Part-B component contaminated by moisture
can become a source excessive bubbles in the product after mixed
with part-A. Avoid exposure of the material to moisture in air.
empty space in the container with dry nitrogen gas, argon gas, or
negative-40-degree-due-point dry air is also recommended to prevent
moisture contamination of part-B as well. (However, simply keeping
the material in an airtight container may also be sufficient
depending on the moisture level of the work place.)
Store it in
a dry indoor storage at a room temperature between 65 and 90 ºF.
Avoid direct sunlight.
Moisture contamination of part-B material can be reversed by heating
material to 180 ºF and vacuuming it at about 29" Hg or above
negative pressure for 20 to 40 minutes.
material contains chemical constituents that can separate during the
storage. Agitation of the part-B content before dispensing may be
required if stored for a long time. Separation can be seen in a
higher degree when the material is stored in cold temperature. You
may need to heat to re-blend the separated material in some cases.
Please consult Northstar Polymers when separation is suspected.
component materials are industrial-grade chemicals. Please keep
them in a secure place and prevent access from any unauthorized
individual. The personnel who handle these materials need to read
the Safety Data Sheet (SDS) for detail information on safety and
handling of the material. The SDS for each component is sent with
the shipment of the material.
this material, be sure to operate in a wide-open area with good air
movement, or in a well-ventilated area. Wear rubber gloves, long
sleeves, and protective eyeglasses to prevent skin/eye contact of
the material. When your operation involves heating or spraying of
the material, and if you expect the isocyanate content level in the
work place atmosphere may become above the threshold regulated by
OSHA or by other appropriate working place safety standard, we
recommend, in addition to the above, installation of a proper hooded
dynamic ventilation system and/or using an appropriate type of
respirator (such as a full-face respirator equipped with OSHA
approved HEPA filters for particulate and organic vapor) to prevent
inhalation of the fume.
contact of polyurethane raw materials to skin/eye, as well as
ingestion may lead to health problems. No eating or smoking should
be permitted at the working area. The operator should wash hands
well with soap and water after handling the materials and follow the
other procedures of the Standard Industrial Hygiene Practices.
Please refer to the MSDS for each component for the detailed health
questions, please contact Northstar Polymers.
All of the statements, recommendations, suggestions, and data
concerning the subject material are based on our laboratory results,
and although we believe the same to be reliable, we expressly do not
represent, warrant, or guarantee the accuracy, completeness, or
reliability of same, or the material or the results to be obtained
from the use thereof, neither do we warrant that any such use,
either alone or in combination with other materials, shall be free
of the rightful claim of any third party by way of INFRINGEMENT or
the like, and NORTHSTAR POLYMERS AND TANDEM PRODUCTS DISCLAIM ALL
WARRANTIES, EXPRESS OR IMPLIED, OF MERCHANTABILITY and FITNESS FOR A