Easy Hand-Mixable/Pourable Flexible Foam
7 Pound-Per-Cubic-Foot Density
foam formulation is designed to make molded flexible foam parts/sheets/dies/blocks
by hand-mixing with very basic tools such as a cup and stir stick. The components are low-viscosity stable
liquid at room temperature. These
properties are ideal in small scale productions for custom foam applications
such as custom seating, padding, cushioning, many others.
The free-rise density of the foam is 6 to 7 pounds per cubic foot. The
cell structure is partially open-cell, and may be made to open-cell structure
by physically crushing soon after foam is made. This is an MDI base water-blown polyether system,
and it does not use auxiliary blowing agents
Examples for Applications:
- Molded Upholstery Parts
- Custom Seating, Padding, and Cushioning
- Custom Packaging of
Physical Properties of the Cured Foam
Density (Free Rise)
OO 10 – 40
*Note: The foam color is expected to turn to dark yellow from light, heat,
and oxidation after exposure to ambient condition for a while.
(Part-A) Curing Agent (Part-B)
Code Number: MPB-028 PPC-026
Specific Gravity: 1.108 1.024
Equivalent Weight: 290 268
%NCO 14.5 % n/a
In the cold season, part-A component (MPB-028) may freeze during the
shipping. If the material arrives
frozen, it must be thawed immediately.
To thaw MPB-028, the entire content needs to be heated to about 140
˚F. After the material is thawed
to homogeneously smooth liquid consistency, the container top space needs to
be purged with nitrogen gas and kept in an air tight container to store. The storage temperature should be within
the range of 72 to 90 ˚F. Part-B
component (PPC-026) is not likely to freeze in normal weather condition in
Mixing Ratio (A) (B)
Volume Ratio: 100 100
Weight Ratio: 100 93
Stoichiometry: 1.00 1.00
NCO Index 1.00 1.00
Temperature (70 – 85 ˚F)
Temperature (70 – 85 ˚F)
Mold/Substrate Room Temperature (70 – 85
can be at ambient temperature if it is made of plastic, resin, wood, or paper. When casting on metal or other
heat-absorbing materials, the substrate may need to be heated to 100 – 140
Pot life (pour within) 60 - 80 seconds
Demolding time 1
to 2 hours
Complete Cure Cycle: 48
hours at room temperature
We recommend testing small amounts to see how the material behaves,
then develop your processing method accordingly. In here, the descriptions are for the
manual hand-mixing process. When you process/test, please be sure to
operate in a well-ventilated area or large open area with a fan to move air;
wear rubber gloves, long sleeves, and protective eyeglasses to avoid skin/eye
contact. Read the Material Safety Data
Sheet for the details on safety and handling of each component.
Amount of foam enters into the mold is important to mold your foam
parts at the right density. Measure
your in-mold volume in cubic inches.
Divide it by 1728 to obtain the volume in cubic foot. Multiply by 7 to obtain the weight needed
in the mold to get the 7 pounds per cubic foot density foam in pounds. Use the mixing ratio supplied in this
document to batch the foam resin. The
foam expands by approximately 9 to 10 times of the liquid volume.
About 1 to 2 hours after casting the foam resin, the foam should be
solid enough to de-mold. At this
point, foam is expected to have a closed-cell structure. This closed-cell foam may shrink badly
after it cools down. In order to avoid
the shrinkage, the foam should be crushed down physically to force the
internal cell structure to be open-cell.
At first, the foam feels like a balloon when you press. You would hear popping sounds as you crush
the foam. You should crush all regions
of the molded foam part so that the foam deflects equally throughout the part.
Foam needs to fill the mold space by put slightly larger amount of
foam into the mold. The expansion
pressure of the foam sends the foam material to fill the mold to the expected
shape. The mold, therefore, needs to
be a closed mold and has to have a capacity to retain the internal
pressure. A simplest compression mold
will be an open-top box with a lid.
The lid needs to be clamped to hold the pressure.
The air trapped in the mold could make large voids if it is not vented. For this purpose, you need to have very
small holes to let the trapped air escape from the mold. Determine the mold position so that trap
air is pushed toward a corner or sections where the vent holes are. Small amounts of the foam may squeeze out
from the vent holes, which you can machine off after the part is cured.
The mold material can be metal, plastic, or elastomeric material. Mold surface needs to be slick as foam
could stick to any porous surface.
Metal molds tend to absorb heat.
The heat created from urethane reaction is required for foam to cure
properly. If mold is cold, this heat
is absorbed and the foam does not cure properly. The mold needs to be heat to 100 to 140 ºF
range in case of using metal molds. If
your mold is made of a plastic or elastomeric material, such as silicone
rubber, epoxy, and urethane, this may not be necessary. Please test and determine the optimal
temperature for your mold. Higher mold
temperature increases the shrinkage rate.
For tight shrinkage variation, controlling temperature parameters is
The “compression rate” describes the additional amount of material you
would put into the closed mold to create the internal pressure so that the
foam fills the entire inside space of the mold. Typically, about 5 to10 % compression should
give enough pressure to distribute the foam within the mold. Using higher rate makes the foam denser and
stronger. However, it will increase
the chance of closed-cell/shrinkage problem described below.
Applications that requires fire-retardant property:
This foam is
not fire-retardant foam, and it is not recommended for applications,
which require or should be using fire-retardant grade materials. The applications such as automotive
interior, building material, and components for some electronic parts often
require fire-retardant grade materials by law. It is the user's
responsibility to conform to the applicable regulations. We also do not recommend this foam to be
used to the applications in which the foam can be exposed to high temperature
or being near an ignition source.
By adding fire
retardant additives, this foam may be modified to fire-retardant grade
foam. The user must test the foam
modified with the fire retardant additives for the fire-retardant property
and the conformance to the applicable regulations.
(prepolymer) contains isocyanate component, which is very much 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 a can and dispensing the
content, nitrogen gas or argon gas needs to be injected to the can to blanket
the material. Silica gel or calcium
chloride desiccant filter should be installed to 55 gallon drum-vent for your
drum feeding system. The storage
temperature should be at a room temperature between 72 and 90 ºF.
component is hygroscopic. If the
material is exposed to ambient air, it may absorb moisture. Moisture
contaminated part-B material may become source of degradation or excessive
bubbles in the product. Avoid exposure of the material to air. Purging the empty space in the container
with nitrogen gas or negative-40-degree-due-point dry air is also recommended
to prevent moisture contamination of part-B as well. The storage temperature
should be at a room temperature between 65 and 90 ºF.
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 Material Safety Data Sheet (MSDS) for detail information on
safety and handling of the material.
The MSDS for each component is sent with the shipment of the
using this material, please 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, we recommend, in addition to the above, installation
of a proper ventilation system and using a half-face respirator recommended
for the use 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.
Please refer to the MSDS for each component for the detailed health
questions, please contact Northstar Polymers.
Web Site: http://www.northstarpolymers.com
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 DISCLAIMS ALL
WARRANTIES, EXPRESS OR IMPLIED, OF MERCHANTABILITY and FITNESS FOR A
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