Product Description

DE NEEF® Flex SLV PURe is an ultra low viscosity hydrophobic polyurethane designed to be injected into hairline cracks in concrete structures. DE NEEF® Flex SLV PURe grout expands on contact with water and quickly cures to a tough, flexible foam that is resistant to most organic solvents, mild acids, alkali, petroleum and micro-organisms.

    Product Advantages

    • Super Low Viscosity for hairline cracks
    • Free Foam Expansion up to 18 times
    • Contains no volatile solvents
    • Single Component
    • Controlled reaction time
    • Improved low temperature performance
    • Flex Cat PURe liquid to -40°F

    Product Applications

    • Sealing fine and hairline leaking cracks in concrete 0.02” and finer
    • Injecting grout tubes (INJECTO® )

    Installation Guidelines

    Warning: DE NEEF® Flex SLV PURe must be used with DE NEEF® Flex Cat PURe. Consult the Technical Data Sheets and SDS before using.

    Installation Instructions: For detailed installation instructions refer to the DE NEEF® technical bulletin for your application.

    Catalyst: Shake catalyst can 2-3 minutes. Pour the desired amount of Flex SLV PURe into a clean dry pail. Measure the appropriate amount of Flex Cat PURe (refer to the Reaction Times section of this data sheet for the desired set time) and pour it into the pail. Stir until adequately mixed. Exceeding the recommended amount of catalyst may adversely affect the reaction and quality of the cured foam.

    Injection: During injection the grout will follow the path of least resistance. When the material has stopped penetrating it will continue to expand against the limits of the confined space and compress within itself,forming a dense, closed cell foam.

    Extreme conditions: For application procedures in extreme temperatures and specific environments or equipment recommendations call the DE NEEF® Technical Service Department.

    Cleaning: Clean all tools and equipment which have been in contact with the resin with DE NEEF® Washing Agent before resin has cured. Products should be disposed of according to local, state, and federal laws.

    Reaction Times

    40°F 2 6’30” 14V
      5 3’25” 16V
    60°F 2 5’10” 16V
      5 2’35” 16V
    77°F 2 4’30” 16V
      5 2’20” 17V
    86°F 2 4’20” 16V
      5 2’00” 17V
    95°F 2 3’35” 17V
      5 1’45” 18V

    Packaging & Handling

    DE NEEF® Flex SLV PURe:

    5 gallon metal pail
    50 gallon metal drum

    DE NEEF® Flex Cat PURe:

    25 fl. oz. in 1 qt. metal cans

    DE NEEF® Flex SLV PURe is sealed under dry nitrogen because it is sensitive to moisture, and should be stored in original containers in a dry area. Storage temperature must be between 40°F and 90°F. Once the packaging has been opened, the useful life of the material is greatly reduced and should be used as soon as possible. Shelf life: 2 years.

    Health and Safety

    Always use protective clothing, gloves and goggles consistent with OSHA regulations. Avoid eye and skin contact. Do not ingest. Refer to SDS. For emergencies, call CHEMTREC 1-800-424-9300.


    DE NEEF® Flex SLV PURe must be used with DE NEEF® Flex Cat PURe.

    Low temperatures will significantly affect viscosity. Flex SLV PURe is not designed for void filling and must be used in compression. If site temperatures are extremely low, heat bands or heated water baths may be used on the pails before and during installation to maintain the product’s temperature. Avoid splashing water into open containers, as the material is water activated. Avoid exceeding 90⁰F when warming.

    CAUTION: pH NOTICE. Water used to activate PURe Grouts must be in the pH range of 3-10 for optimum foam quality.


    Solids 100% ASTM D2369
    Viscosity 200 cps at 77°F ASTM D2196
    Color Pale yellow  
    Density 1.02 g/cm3 ASTM D4659
    Flashpoint >270°F ASTM D93
    Corrosiveness Non-corrosive  
    Viscosity 15 cps at 77°F ASTM D2196
    Color Clear to pale grey  
    Flashpoint 221°F ASTM D93
    Density confined 1.00 g/cm3 ASTM D3574
    Density free about 3 PCF ASTM D3574
    Tensile strength >174 psi ASTM D3574
    Elongation % 100 ASTM D3574