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patex hs series

Eco-Leather high solid PU-based system


The HS SARP OX FREE system is a combination of polyurethane-based polymers. This composition is particularly elastic and does not require plasticizers to make the material flexible and plastic. Therefore, there is no need for the FTALATES that are included in the California Prop 65 as undesired substances, nor for the FTALATES that are part of the Candidate List of the European Reach. We can say that HS SARP OX FREE are FTALATE FREE.

The HS SARP OX FREE system is a set of high-solids polyurethanes that do not contain the solvent DMF and do not need to be diluted with this solvent to be coated and processed. This eliminates a toxic solvent that is on both Prop 65 and the Reach Candidate List. DMF is essential in the production of PU coagulates because it is water soluble and allows polyurethanes to coagulate on various substrates. The HS SARP OX FREE system is a valid alternative to polyurethane coagulates and the process is DMF FREE.

The HS SARP OX FREE system does not contain solvents, such as alcohol, toluene or glycols like other polyurethanes because it is based on a dispersed mass polymerization and therefore does not require a solvent medium to bring the molecules together and make them react. Therefore, it is not part of those polyurethanes that, although DMF free, contain other solvents with different emissions from DMF but which remain and are not eliminated. For this reason we can say that HS SARP OX FREE are SOLVENT FREE and consequently VOC FREE.

An important peculiarity of HS SARP OX FREE polyurethanes is the absence of oximes, which are used during the polymerization of high solid polyurethanes and which give the product a particularly annoying smell. Thanks to the studies carried out in our laboratory and in collaboration with professors of the Polytechnic of Milan, we were able to obtain patent no. 10201500016593 which certifies an innovative process and products with a quality that did not exist before and this without the use of ketoxime. We can therefore say that the HS SARP are OXIMA FREE.

HS SARP OX FREE products are solvent-free polyurethanes and therefore can be added with expanding agents able to develop a cellular structure increasing the thickness with the same weight. This makes it possible to lower the weight of the finished products with the same thickness, as is normally done with PVC products. Moreover, the density of the non-foamed polymer is 35% lower than that of the PVC polymer. We can therefore say that HS SARP OX FREE coated products are a valid alternative to PVC coated products.

HS SARP OX FREE products are polyether based polyurethanes, different from most polyurethanes which are polyester based. This difference is very important for the "life" of the polymer which, as we have said, is subject to degradation due to the effect of water and temperature. The presence of a long chain with an ether base and therefore hydrophobic makes these polymers less attackable and more resistant in normal application conditions and particularly suitable in the furniture and automotive sectors.

HS SARP OX FREE products, formulated, catalysed and cross-linked as indicated in the technical data sheets, form an elastic and flexible film, insoluble not only in traditional technical solvents (able to guarantee very strong gluing, toluene, glycols) but also in DMF. This characteristic allows the use of aggressive glues able to guarantee very strong bonding, even in difficult positions.

Polyurethanes in general and therefore also those of the HS SARP OX FREE system are polymers that contain urethane chemical bonds, which are very polar because they are made up of carbon, oxygen and nitrogen. This polarity allows water, water vapour and humidity, with the help of temperature, to attack the bond, cause it to break and demolish the product. They are therefore environmentally friendly, compostable and degradable materials.

The HS SARP OX FREE products, formulated and processed as indicated in our technical specifications, pass the ISO 10993 part 5 and part 10 standards for biocompatibility: the results are very positive, so we can declare that these materials are biocompatible, i.e. they are not cytotoxic, they do not cause allergies and skin irritations. They can therefore be used without problems even for materials in contact with the skin. This is confirmed by the fact that they do not contain the products listed in the European ecological standard OEKOTEX standard 100 for the use of materials in contact with the skin (class II).




Results resistance to HYDROLISIS

Tropical Test - temperature 70°C - humidity 95% - time 1 - 4 weeks


  • PATEX SR 20
  • PATEX HS SERIES colours




Expansion results
PATEX HS - coating weight 300g/m²
amount of PATEX BLOWING 50
0% - 3% - 6% - 9% - 12%