9 Pound-per-cubic-foot Semi-Rigid Foam

Used in hand-mix/cast-in-place, and low pressure machine casting operations


This foam polyurethane formulation is designed to yield structural foam by either hand-mixing or machine casting method. The pot-life of this material is longer than ordinary rigid foam formulations to allow enough handling time in a hand-mixing operation or a low-pressure meter-mixing machine. Unlike common rigid foam formulation, the semi-rigid foam structure of MPS-M09A resists cracking and chipping from impact force by slight flexibility. This combination of features makes MPS-M09A ideal for cat-in-place insulation, molding compound for structural parts, and many other custom applications.

This formulation does not use auxiliary blowing agent such as Freon, HCFC, CFC, or flammable hydrocarbon materials. The components are liquid at room temperature. For a small quantity, this can be batched manually by hand tools. This can also be cast with a multi-component meter-mixing/dispensing machine. The free-rise density of the foam is 9 pounds-per-cubic-foot, the cell structure is closed-cell.

Component Properties

%NCO 23 % n/a

Mixing Ratio (A) (B)

Processing Temperature:

Cure Pattern:

Recommended Processing:

I recommend testing small amounts to see how the material behaves, then develop your casting method accordingly. When you do test batch, please be sure to operate in a well-ventilated area or large open area, wear rubber gloves, long sleeves, and protective eyeglasses to avoid skin/eye contact. Read the enclosed Material Safety Data Sheet for details on the safety and handling.

Before you start your test, there is a chance the materials being frozen during the transportation. This may cause separation within the components. If in such case, you need to agitate the components in the cans. Do not open the can for part-A (MSA-018) until you are ready to use as it is a moisture sensitive material. Shake the unopened can to agitate. You can open the can for part-B (PPX-008) and use a metal spatula or knife (or something dry, strong, and clean) to agitate. Do not use wooden paint stick as it has moisture within, it may contaminate the material. After agitating the components, keep them at a room temperature above 70 F. These materials will not freeze at room temperature.

Compression Molding

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. The mold therefore needs to be a close mold and has to have some capacity to retain the expansion pressure. The simplest mold will be just an open-top box with a lid. The lid then needs to be clamped hold the pressure. The air trapped on the top side of the mold could make a large void if it is not released. For this purpose, you need to have a very small vent (hair vent) to let the trapped air escape from the mold.

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 the heat. Heat created from the chemical reaction is required for foam to cure. If mold is cold, this heat is absorbed and the foam does not cure properly. The mold needs to be heat to 100 to 110 F in case of metal molds if metal mold. If your mold is plastic or elastomeric mold, this may not be necessary as those materials retain heat better than metal molds.

Compression rate indicates how much more of component material is put into the mold. The rate indicates the percentage of excess amount of material to the amount in which to fill the mold using the foams free-rise density. Typically, about 10 % compression should give enough pressure to distribute the foam within the mold. Using higher rate makes the foam denser and stronger.

Applications with fire-retardant grade

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. Contact Northstar Polymers for source information.

Deflection Temperature

All semi-rigid foams soften as operating temperature rises. If load bearing capacity is required at an elevated temperature, test the structural integrity of the foam parts at the expected operating temperature for the application.


Handling Information for the Component Materials


Part-A component (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 negative-40-degree-due-point dry air 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 65 and 80 F.

Part-B 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; however most of the cases, keeping in an airtight container will be sufficient. Store it in a dry indoor storage at a room temperature between 65 and 80 F. The moisture contamination of part-B material is reversible. By heating material to 160 - 180 F and vacuuming it at about 29" Hg negative pressure for several hours will reduce the moisture level.


The component materials are industrial-grade chemicals. Please keep them in a secure place and prevent access from any unauthorized individual. The personnel who handles these materials needs 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 material.

When using 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, we recommend, in addition to the above, installation of a proper ventilation system and/or using an appropriate type of respirator to prevent inhalation of the fume.

Direct 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 information.

For any questions, please contact Northstar Polymers.


Northstar Polymers

3444 Dight Avenue South

Minneapolis, MN 55406 USA

Tel: (612)721-2911

Fax: (612) 721-1009

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Notice: 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 PARTICULAR PURPOSE.