FAQ

Frequently Asked Questions

We have summarized frequently asked questions for you here and answered them so that you can get a quick and comprehensive overview of the subject of polyurethane or just to get a feel for polyurethane.

 

If you have come to the conclusion that polyurethane could basically work for your application, our contact persons are available to you at any time for extensive advice.

What is polyurethane? 

Polyurethane is often abbreviated to PU or PUR. The polyurethane systems developed by POLYTEC INDUSTRIAL are called TECTHAN and THELAN.

 

Polyurethane is a reaction plastic. It is created by mixing two liquid raw materials, the polyol and the isocyanate. The chemical reaction is called polyaddition.

The addition reaction of the OH group with the isocyanate group forms an urethane group, which forms the polyurethane as a chain compound. The polyurethane elastomers are divided into polyester urethanes, which generally have better mechanical properties, and polyether urethanes, which have the better hydrolysis properties. Both have excellent wear behavior, high tear resistance and elasticity.

Depending on the type of raw materials used, polyurethanes show a wide variety of forms and properties.

What is the difference between polyurethane and Vulkollan®? 

Vulkollan® is "only" a polyurethane and is the trade name of Covestro AG (formerly Bayer AG). Due to the use of Desmodur 15 isocyanate, it is also known under the quality name Polyurethane D15.

 

Vulkollan has its strengths in the application of highly dynamic loads. But it doesn't always have to be Vulkollan.

 

At POLYTEC INDUSTRIAL, in addition to Vulkollan, we also process a large number (over 130 recipes) of our own formulations in order to be able to respond to a wide variety of applications from our customers. All common systems (TDI, NDI, MDI ...) are used.

What are the properties of polyurethane? 

The properties of PU are diverse and suitable for a wide variety of industrial applications. The material is highly resilient, flexible and resistant to a large number of chemical substances.

 

Typical properties are: Highly elastic, break-proof, dimensional stability, sprayable, antistatic, machinable, cut-resistant, UV-resistant, highly wear-resistant, hydrolysis-resistant, microbe-stable, corrosion-free, seawater-resistant and last but not least cold and heat resistant.

What are typical areas of application for polyurethane? 

Typical applications for polyurethane can be found in almost all branches of industry, just a few examples:

Metal, steel and sheet metal processing: For all kinds of rollers, scrapers, coil storage mats, coatings, surface grinding systems, vibrating troughs, etc., punching pads.

 

Construction and processing technology: For sieve stars, conveying elements, concrete spray nozzles, slides, channels, funnels and bunkers, plates, pump parts, screw conveyors.

 

Special vehicle construction and winter service: For finishers, scraper bars, throwing limiters, clearing plates, rocker arms, forklift tines and mandrels, aircraft choks, snow plow bars, suction shafts.

 

Mechanical and plant engineering: For no-crush rollers, buffers, bushes, springs, pump parts, wheels and rollers of all kinds, dosing funnels, lifters and grippers, strips, semi-finished products.

 

Maritime industry: For boat and dock fenders, floats, pipe interior coatings.

 

Energy and supply technology: For buried fittings such as ball valves, slides and house connections, as well as pipe inner and outer coatings.

 

Polyurethane is also used in many everyday things, e.g. in: Gym and work shoes, play equipment such as swing seats and soccer balls, clothing, carpets, assembly foams, seals, seat cushions and mattresses, paints and much much more.

How is polyurethane processed? 

POLYTEC INDUSTRIAL processes polyurethane in various processes

  • Casting into open moulds
  • Centrifugal casting (production of plates)
  • Rotational casting (coating of roller bodies)
  • Foam
  • Hot spray process

 

The hot casting process is a pressure-free manufacturing process for the production of molded components.

Since it is usually a manual process, it is used for the production of small to small series components (1 - 10,000 pieces)

 

Advantages:

  • low molding costs compared to injection molding
  • mechanically more resilient compared to cold casting systems
  • Component weights from 2 gr. To 1.5 tons are possible

 

We offer a wide variety of polyurethane systems for the hot spray process, which include can be used as wear or corrosion protection. Large-area components and / or free-form surfaces are mainly coated in this process. Depending on the application, coating thicknesses of 1 - 40 mm are possible.

How do the properties of cast and sprayed polyurethane differ? 

The processing takes place as a multi-component system in the casting process for the production of technically demanding molded parts or in the spraying process as a wear protection coating of large components. In contrast to the casting process, the spray coating is not shape-bound.

 

Another difference between sprayed and cast polyurethane is density. While the density when spraying is 1.0 Kg / dm³, the density when pouring is 1.1-1.26 Kg / dm³ depending on the recipe.

 

POLYTEC THELEN and POLYTEC ELASTOFORM process almost all common raw material systems in the hardness range from 40 Shore A to 75 Shore D - this also includes Vulkollan® * D15.

Can polyurethane be used in the food sector? 

For use in the food sector, polyurethane must comply with the regulations of the European Plastics Regulation (EU) No. 10/2011 and Regulation (EU) No. 1935/2004.

 

At POLYTEC INDUSTRIAL we process special recipes with a Shore hardness of 70 ° and 90 ° Shore A, which are certified for use with dry media.

 

Available in the colors white, blue and of course without color pigmentation.

Is polyurethane recyclable? 

Yes, polyurethane is recyclable. There are different ways to recycle PU. To date, however, it has not yet been possible to restore the PU produced to its basic materials polyol and iso (isocyanate).

 

There are other ways to recycle / dispose of PU; one way is to clean, shred, and then add a certain percentage to a new product.

 

Another possibility is to burn PU in a waste incineration plant in a controlled manner in order to use the resulting energy. The problem with burning is the resulting toxins such as: isocyanates, hydrocyanic acid and dioxins.

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