Residual moisture in the pipe?
Pretreatment instead of tedious drying. Reliable coating despite residual moisture.
When rehabilitating old asbestos-cement wastewater pipes, residual moisture can slow down the process. Together with CN Technik, Collano is therefore testing a pretreatment that can be applied to the still moist inner surface after preparation. In the field trial conducted so far, the PUR coating could then be applied without the need for additional hot-air drying.
Drying takes time
Before trenchless rehabilitation, the inner surfaces of existing asbestos-cement wastewater pipes are mechanically prepared. Uneven areas and contaminants are removed in the process. The surface must then be sufficiently dry to ensure reliable adhesion of the PUR coating. However, residual moisture can remain, particularly at pipe joints, transitions and hard-to-reach areas. Until now, these areas therefore had to be additionally dried using hot air. CN Technik was looking for a solution that would simplify this step and fit into the existing rehabilitation process.
Easy to apply. Easy to integrate.
The pretreatment needed to be suitable for direct application to the still moist inner pipe surface immediately after mechanical preparation. Easy application by brush was required, both over entire pipe sections and selectively at joints and transitions. At the same time, the pretreatment was intended to complement the existing rehabilitation process. In the field trial, it was therefore combined with the PUR coating system used to date.
Working together to tackle residual moisture
Since September 2025, Collano and CN Technik have been testing the pretreatment under real-world conditions. After mechanical preparation, CN Technik applies the pretreatment thinly and evenly with a brush to the still moist inner surface of the pipe. Depending on the condition of the existing pipe, a second coat may be required. The two companies work closely together to coordinate substrate preparation, brush application and the subsequent PUR coating. Collano assesses the substrate and supports CN Technik in integrating the material into the existing rehabilitation process.
Less drying, faster coating
In the field trial conducted so far, CN Technik was able to dispense with additional hot-air drying after applying the pretreatment. Depending on the ambient temperature and amount applied, the surface was ready for PUR coating after approximately 10 to 20 minutes. This eliminates the need for a separate drying step. It simplifies the workflow and reduces the use of hot-air equipment. Residual moisture can be bridged, particularly at pipe joints, transitions and hard-to-reach areas.
Project data
- Project
-
Pretreatment of asbestos-cement wastewater pipes with residual moisture
- Period
-
Ongoing field trial since September 2025
- Application
-
Pretreatment of damp inner pipe surfaces prior to PUR coating
- Customer
-
CN Technik, Bachenbülach, Switzerland
- Product
-
Collano VP 2132, silane-terminated polymers
- Preparation
-
Thin and even brush application; entire surface or selected areas
- Layer thickness
-
Estimated at approx. 0.05 to 0.1 mm
- Sustainability
-
Potential to reduce energy consumption by eliminating additional hot-air drying as demonstrated in field trials to date.
- Website
Residual moisture at pipe joints and transitions repeatedly delayed our workflow in the past. With Collano VP 2132, we can prepare these areas and continue coating after just a short time. Collano provides hands-on support during the trials and helps us integrate the solution into our process.
Dealing with residual moisture during pipe rehabilitation?
We'll work with you to determine whether Collano VP 2132 is suitable for your coating system and process. Let’s talk.
Adhesive solutions for trenchless pipe rehabilitation Link opens in a new tab.
