1. B
    • Brittleness
      Polyurethane based OCF have the tendency to become brittle during the curing phase, mainly at cold temperatures. This property usually disappears irretrievably at warming. Though the foam becomes flexible at higher temperatures, the brittleness may remain permanent in cold conditions and affect the applicability of the foam. The lower the brittle point, the better the foam quality.**
  2. C
    • Compression strength
      One of the main application areas of OCF is the thermal insulation and sound damping in connection joints. Those joints have to absorb the movement of the construction elements caused by temperature change, wind load etc. and have to provide certain flexibility to withstand a long duration. This flexibility can be measured by the compression force of a piece of the foam. The result is proportional to the extent of compression. A typical value is a compression by 10 %.***

    • Curing pressure
      Curing pressure describes the pressure which is generated by the foam during its curing process. Curing pressure arises from the curing (herdening) and at the same time expanding foam. The force can deform the substrates like weak frames, when not secured by clamps during the curing time.

    • Cutting time
      The time after which cutting a cylindrically shaped string of (not entirely hardened) foam, 3 cm in diameter, leaves no fresh foam residues on the knife and when the cells are not squeezed and destroyed through the knife any more. It is a time after which the foam is not entirely hardened, but it can be processed.  At minus temperatures the expansion of foam is lower and curing time is always longer.

    • CFC
      Any of various halocarbon compounds consisting of carbon, hydrogen, chlorine, and fluorine, once used widely as aerosol propellants and refrigerants. Chlorofluorocarbons are believed to cause depletion of the atmospheric ozone layer (ODP) and also affect Global Warming (GWP).* All PU foams in MARKOFLEX range are CFC free.
  3. D
    • DME
      Dimethyl Ether
      Typical propellant in OCF applications*
  4. F
    • Flexibility of PU foam
      Window frames are consistently under stress due to opening and closing, thermal expansion (i.e. via heat derived from direct sunlight), thermal contraction (cool/cold temperatures), strong temperature differences between inside and outside at the same time (40 °C and more) and heavy weather conditions (i.e. winds). A flexible PU Foam can withstand such movements without breaking over long periods, maintaining it’s insulation function (both thermal and sound).

    • Flame retardant
      An added substance which inhibits the initiation and/or spread of flame*


    • FEICA
      FEICA is a multinational association representing the European adhesive and sealant industry, including one component foam manufacturers. Further information at:
      Henkel uses test methods approved by FEICA designed to deliver transparent and reproducible test results, ensuring customers have an accurate representation of product performance. FEICA OCF test methods are available at: 


  5. G
    • GWP
      Greenhouse Warming Potential
      Measure of the potential of substances to heat up the atmosphere. All measures of GWP are given relative to Carbon dioxide, the most well-known gas with global warming potential, which has a GWP of 1.
      HFC 134a is referred to by the Environmental Protection Agency as High Global Warming Potential gas. Historically used as a blowing agent by most OCF manufacturers, HFC 134a has a global warming potential of 1300, which means it has 1300 times the global warming potential of carbon dioxide.* Henkel switched to R 134a free formulations far ahead of the legal prohibition.
  6. H
    • HFC
      Non-fully halogenated fluorocarbons.
      HFCs have replaced ozone-depleting chlorofluorocarbons (CFCs) in many applications but are powerful greenhouse gases, with 100-year global warming potential of between 140 and 11,700.
      In OCF applications most of these HFC’s are replaced by propane/ butane/ DME combinations.

  7. I
    • Isocyanate
      A substance containing an isocyanate (-N =C=O) group. A polyisocyanate contains more than one isocyanate group.*
  8. M
    • MDI
      Methylene Diphenyl Diisocyanate
      An abbreviation for 2,2' / 2,4' and 4,4'- Methylene diphenyl diisocyanate. MDI is an aromatic isocyanate and a key polyurethane raw material.* MDI is a chemical substance. It reacts with polyols in the manufacture of polyurethane where it acts as the hardening agent for the froth. MDI reacts with water and solidifies. It attributes the brown/beige color to traditional PU foams and makes them highly UV sensitive – letting PU Foams brittle under sunlight.
  9. N
    • Norm climate
      23 °C/ 50 % R.H.
  10. O
    • OCF
      One Component Foam (literally)
      Generic for moisture curing One Component Foams dispensed from pressurised containers (“aerosol cans”) as well as self-curing two component foams dispensed from pressurised containers (“1,5 component foams”).
  11. P
    • PE

    • Polyurethane
      Polymeric substance containing many urethane linkages (-N-C-O-). Abbreviated as PU.

    • PU foam structure
      To achieve the required properties and characteristics (e.g. thermal and sound insulation) the applied PU foam should have a homogeneous and fine cellular structure (no large voids and bubbles inside). This is achieved with carefully balanced chemical formulation.

    • Porous material
      Porous materials are materials that let liquids and/or gases pass through them – either partially or totally (e.g. wood, fiber glass, cork…).
      Non-porous material, on the other hand, doesn’t let any liquids and gases get through (e.g. glass, metals, plastics).
  12. R
    • R.H.
      Relative Humidity
      The ratio expressed as a percentage of the amount of moisture air actually contains to the maximum amount it could contain at that temperature.

  13. S
    • Sagging
      One of the most important properties of an OCF is the ability to set itself in a cavity and thus fill up joints. The freshly applied foam is liquid (froth) and has therefore no internal strength. This can lead to foam collapse and to slipping down, especially in vertical joints.
      This property depends on the product and ambient temperature and the width of the joint. The typical factors for sagging are too low temperatures and too wide joints.

    • Shear strength
      The shear strength is an important property of the foam, needed to evaluate its fixing power, particularly for the fixation of doorframes. It is useful to calculate the necessary area of fixation (for given door wing weight) or vice versa. This test also indicates the breaking point of the fixation, which can be either within the foam (cohesion failure) or between foam and the bonded surface (adhesion failure).
  14. T
    • Tack free time
      The time after which the surface of the foam, sealant or adhesive is tack free.
  15. Y
    • Yield of PU foam
      Yeild is the volume of a finally cured foam from the whole can. Yield of the cured foam largely depends on of working conditions – temperature, air humidity, available space for expanding, etc. The yield can be measured in the box and in the joint. PU Foam behave completely different in both cases. The “box test” is standardized and accepted by the Association of the largest European OCF manufacturers. It is reproducible and gives the foam yield in litres. The measurement of the joint length might be easier to understand by the consumer as the foam is mostly used to fill joints, however this method is not reproducible and can be easily influenced by the operator to favor the own product. The result then is expressed in running meters.

* Source: FEICA OCF GLOSSARY RAM-C02-0004,
** Source: FEICA TM-1008-2011 v3 ,
*** Source: FEICA TM-1011-2011 v4 ,
**** Source: FEICA TM-1012-2012 v4 ,