With the diversification of modern building functions, more and more waterproof coatings are applied in buildings. However, due to the semi-finished waterproof materials, when the materials under strict quality control arrive at customers, some problems will inevitably occur due to transportation, construction and other reasons. Today, the causes, solutions and precautions of common problems in customer applications are analyzed to use of late customers to avoid risks.

1. One component polyurethane waterproof coating will gradually thicken and agglomerate when placed outdoors in summer

Cause analysis

In the process of loading, unloading and transportation, bumping and collision of the wet curing single component materials lead to poor sealing. If stored in the open air in summer, the temperature is high and there is much rain, the polymerization of water vapor and materials will occur slowly, which will increase the viscosity of the coating and even caking, seriously affecting the use effect.

Solutions

According to the requirements of "storage and transportation" in GB / T 19250-2013 polyurethane waterproof coating standard, the materials shall be kept away from the sun and rain during storage and transportation, and the storage temperature shall be 5 ℃ ~ 40 ℃. Indoor storage is recommended. Single component polyurethane is recommended to be placed upside down, which can play a role of "liquid sealing" by coating, so as to avoid polymerization reaction with moisture in the air.

2. Long drying time or no drying after the construction of two-component polyurethane and one component polyurethane coating.

Cause analysis

① The two-component polyurethane is not used in strict accordance with the proportion of the instruction manual, resulting in the lack of local NCO or curing chain extender, curing without strength or even unable to cure

② The diluent containing active H + is added during the construction of two-component polyurethane, which consumes the free NCO active group in the coating, and the two-component a cannot react with the solidified component in B to form a film; the diluent containing active H + is added during the construction of one component, and the coating cannot react with water to form a film, resulting in the coating not drying.

③ The amount of diluent added is too large, and the diluent volatilizes slowly, which leads to the failure of film formation.

④ Polyurethane coating belongs to reactive coating, which is constructed under the condition of low temperature in winter, resulting in relatively long surface drying time.

Solutions

① Mix and weigh in strict accordance with the construction requirements, mix evenly, manual mixing is not recommended, and electric mixer is recommended for more than 2 minutes.

② When the diluent needs to be added, the company's designated model shall be added, and the coating shall be added on a small area first, and the film can be formed normally, and then it can be used in batches.

③ The dosage of diluent is recommended to be less than 5% of the weight of material B.

④ According to GB 50108-2008 technical code for waterproofing of underground engineering and JGJ 298-2013 technical code for indoor waterproofing of residential buildings, the construction temperature is required to be 5 ~ 35 ℃.

Due to the low temperature in winter, polyurethane coating has a long drying time, which does not affect the product performance after drying and curing.

（sourcing：net work）