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+Gel Elastomer
























Northstar Polymers, LLC

3444 Dight Avenue So.

Minneapolis, MN 55406

Tel: 612.721.2911

Fax: 612.721.1009

E-Mail: info@northstarpolymers.com



Northstar Polymers, LLC is a member of Polyurethane Manufacturers Association.


Copy right reserved by Northstar Polymers, LLC 2000 - 2007.







Low Viscosity, Variable Ratio Polyurethane Gel


SAI-1 is custom formulated polyurethane gel material to yield very soft elastomer gel material from low viscosity components at room temperature.  This material is variable mixing ratio so that the user can change the properties of the product simply by changing the same combination of part-A and part-B liquid components.  The material does not contain plasticizer so that it will not leach plasticizer to affect the other plastic material surrounding the gel part, or to cause a severe hardness change in long term use.


Possible application for this material includes potting and encapsulation of optical cables, manufacturing of puncture-free tire layer, cushioning and padding parts by open-cast molding, and many other custom applications.  This material is not designed to be cast directly into flexible film casings.  For such applications, we recommend our standard polyurethane gel formula MPP-V37A.


Material Information:


System Code:                            SAI-1 (Custom Formula)

Part-A:                                                 MPC-022

Part-B:                                                 PAA-109


Processing Temperature:           Ambient (> 70F)

Mixing Ratio:                                Variable


Curing Pattern:


Pot Life:                                   11 12 minutes

Demolding Time:                       1 to 3 hours at room temperature

(Demolding time will be shorter if a heated mold is used.)

Complete Cure Cycle:                3 to 4 days at room temperature.

 *Curing pattern can be shortened by use of heat or addition of catalyst.


Hardness vs. Mixing Ratio Correlation


Stoichiometry Ratio

Weight Ratio

Volume Ratio

Hardness Shore OO

(At 72 F)













48 53







35- 40







28 33







3 6







< 0.1


Note: The hardness is dictated by the stoichiometry ratios between NCO and OH mole numbers.  However, in practice, you can use weight ratio or volume ratio for the guidance.  Please contact Northstar Polymers for more precise method of hardness control.  The above is the result of our lab test, and it is reference only.




Typical Values of the Component Materials:


Typical Properties of Part-A Component


Product Code: 



Isocyanate terminated prepolymer extended with polyester polyol


19.0% (+/- 0.5%)

Amine Equivalent


Specific Gravity:


Appearance at 25 C ( 77 F):

Clear amber colored liquid


Viscosity at 25 C (77 F):

800 1300 cps


Store in a dry indoor storage at room temperature in an airtight container.  The material is highly sensitive to moisture.  After using the content, immediately inject dry nitrogen gas or -40 due-point dry air into the container to blanket the material then store.  Heat will accelerate the subsequent reaction within the material and shorten the shelf life of the material. Avoid high temperature and direct sun light.



Typical Properties of Part-B Component


Product Code: 



Curing agent based on a blend of polyols and additives

OH number:


Equivalent Weight:


Specific Gravity:


Physical State at 25 C ( 77 F):

Clear with slight yellow tint; Liquid


Viscosity at 71 C (160 F):

900 cps (+/- 300)


Store in a dry indoor storage at room temperature in an airtight container.  The material is hygroscopic. For long term storage, inject dry nitrogen gas or -40 due-point dry air into the container to blanket the material. 








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 conducting a test or producing your parts 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 using a half-face respirator recommended for the use 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.  Please refer to the MSDS for each component for the detailed health information.







Part-A (Isocyanate Prepolymer) Component


Part-A 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. Store it in an airtight container in a dry indoor storage within the temperature range between 70 and 90 F. Avoid direct sunlight.


Soon after opening the container to dispense the content, nitrogen gas or negative-40-degree-due-point dry air needs to be injected to the container to blanket the material. The pressured nitrogen gas can be injected for 15 to 20 seconds for 5 gallon pail size containers, and 60 to 120 seconds for 55 gallon size containers depending on the top space.


For gravity-feeding from a 55-gallon drum on a drum cradle, 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.


Note: If large amount of water mixes with a large amount of this material, the exothermic heat can raise the temperature so high that it can start a fire. Keep the storage area free of water. The decomposition of this material by extremely high temperature or fire can cause toxic gasses to be created.  Please read the MSDS for the detailed information.


The component materials could freeze below room temperature.  Also, there are different types of raw materials that could separate within the container while storing.   Indications of frozen material include hazy/cloudy color and high viscosity, gelled, or solid state of the material.   Please contact Northstar Polymer for the thawing method if freezing is suspected.




Part-B (Curative) Component


Part-B 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. 


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, 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 F. Avoid direct sunlight.


Note: Moisture contamination of part-B material can be reversed by heating material to 160 - 180 F and vacuuming it at about 29" Hg negative pressure for several hours.








For any questions, please contact Northstar Polymers.



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.               Issued 3/13

For any questions, please feel free to contact us:


Northstar Polymers, LLC

3444 Dight Avenue South

Minneapolis, MN 55406

Tel: 612.721.2911

Fax: 612.721.1009

E-Mail: info@northstarpolymers.com