PRECOTE surface coating
What is Precote?
The Precote is a varnish like layer which is used in the most diverse types of fastening elements.
Its securing and sealing propery only develops when it is placed under pressure and/or shear during assembly. Shortly after the installation of the coated threaded part, the threads become resistant against vibration and loosening and the proper sealing develops as well. The screws and other threaded parts carry within themselves all the beneficial properties of the Precote by the coating, thus creating the proper solidity screw bond.
The development of the Precote is based on the modern T-microcapsuling technique, with the help of which the widespread tried adhesives used for sealing and fastening are closed up with a thin polymeric wall. During the creation of Precote, the separate substances of the modified 2 element Acrylate microcapsuled systems are mixed into a bonding agent. After applying and drying of the liquid phase Precote, dry and corrosion resistant coating is obtained.
How Precote works?
While the fastening elements coated with Precote are screwed in, the microcapsules in the Precote layer crack due to pressure and/or shear. The liquid components are released from the microcapsules and they harden as adhesive, in this way creating the desired fastening and sealing effect.
The microcapsuled modified Acrylates with their controllable capacity scale, with specific Precote adhesives make the satisfaction of the concrete practical requirements possible, meeting the loading and temperature requirements of the given application.
What are the advantages of the fastening elements coated with Precote?
Precote represents the modern problem solving at such application areas where liquid fastening material is not used until these days because of safety and handling reasons.
The fastening elements coated with Precote don't require any kind of further mechaincal securing or sealing component,
- which may be missed or forgotten,
- which are only effective in case of suitable preparation and usage,
- which products assembly, purchase and storage causes additional expenses,
- which securing and sealing effect are not reliable and/or controversial
Physiologically and toxicologically the Precote coating is harmless, since the liquid adhesives, which are classified among the partially irritant chemicals, are completely isolated by the wall of the capsules.
Assembly of the threaded parts coated with Precote
Essentially during the assembly of the screws and fastening elements coated with Precote the same procedure needs to be followed as in case of the assembly of the uncoated fastening elements; the installation, screw on and the perfect tightening needs to be completed in 5 minutes, before the structual distortion of the polymer could take place.
Bonding duration of the screw-thread coated with Precote
The poliymerization of the dissolved fastening material starts by the assembly of the fastening elements. Since the Precote is a quick bonding technology, the change is measurable already in 10-15 minutes. At room temperature the perfect solidity can be reached in 3 hours. The Precote sets around freezing point as well, but the temperature cannot sink below -20°C. The bonding duration increases with temperature decrease.
Storing of the screw-thread parts coated with Precote
The Precote can be stored for at least 4 years between +10 and +28 °C at a maximum of 65% relative humidity. If the humidity increases to 90% for a short time, it doesn't have an influence on the product quality. Based on this, it can be said that the fastening elements coated with Precote can be stored under the same conditions as the uncoated fastening elements.
The sealing effect of the screw-thread parts coated with Precote
The Precote is always homogene and continous surface coating. After the hardening of the adhesive the fastening elements become perfectly sealed. After the hardening is finished, the Precote can withstand even 350 bar pressure. With this effect the corrosion can be avoided on the contacting surfaces of the fastening elements.
The reuse of screws coated with Precote
We do not recommend to reuse the fastening elements coated with Precote, becasuse their state is completely unpredictable. The screws exposed to high pressure are not built in more than once even if they have no Precote coating. If however it is yet necessary to reuse a component, we recommend the below 2 solutions:
cleaing of the fastening elements and application of anaerob fastening material
providing „new", not yet used compotent coated with Precote as a reserve
If the hardened Precote layered fastening element is moved, loosened or further tightened (eg.: in case of a necessary correction after assembly) the layer gets damaged. As a consequence naturally the previous securing and sealing effect is lost, but the increased frictional factor value of the srew protects from loosening off.
Possibilities and advantages offered by Precote
Precote offers a wide range of solutions for applying coatings capable of securing and sealing screws and threaded components:
- automatic coating in case of especially great quantities,
- manual or automatic coating made with a suitable appliance, for which we have gained expreience during the development of our own coating machines.
The Precote system provides significant advantages especially for those manufacturers and users who continously use the same fastening elements, for example screws, threaded lining, threaded parts etc. in great quantities.
