Have you ever seen such a phenomenon?
Significant shrinkage cracks appear in the glue joints of doors, windows and curtain walls.
The silicone sealant becomes hard and brittle or even pulverized.
Oil flow and rainbow phenomenon appeared in the insulating glass.
...
What is the reason for this?
The direct reason is that the curtain wall doors and windows use silicone sealant filled with mineral oil, referred to as Oil-extended sealant.
In this issue of news, SIWAY will discuss with you the secrets about Oil-extended sealant.
What is Oil-extended sealant ?
To correctly understand the oil-extended sealant, we must first correctly understand the silicone sealant.
However, a large amount of cheap mineral oil is used, so that the service life of the oil-extended sealant is not guaranteed. The content of silicone polymer in the oil-extended sealant is low, and the mineral oil will migrate out after a period of time. The oil-extended sealant has poor aging performance, and the colloid becomes hard, gradually inflexible and severely degummed.
We use the 5000-hour aging test for comparison, and the performance of the oil-extended sealant decreases significantly after 500 hours of acceleration. But the performance of the non-oil-extended silicone sealant remains unchanged after the 5000-hour aging test.
The Hazards of Oil-extended Sealant
So, what are the practical hazards of oil-extended sealant ?
- 1. The oil-extended sealant shrinks obviously, and becomes hard, brittle or even pulverized after aging. The sealant joints will crack and debond, resulting in water leakage of curtain wall doors and windows.
2. The oil-extended sealant leaks oil, causing the hollow butyl sealant to dissolve, and a rainbow phenomenon occurring, resulting in the failure of the hollow glass.
Conclusion: The oil-extended sealant seriously endangers the safety of curtain wall doors and windows, and brings waste of resources to the society. In severe cases, the glass will fall off to endanger personal safety.
So how can we identify oil-extended sealant and reduce the loss caused by oil-extended sealant?
Identification of Oil-extended Sealant
According to GB/T 31851 "Detection method of alkane plasticizer in silicone structural sealant", there are 3 identification methods: Thermogravimetric analysis test method, infrared spectroscopy test analysis method and thermal weight loss. These methods require specialized laboratory equipment.
Here SIWAY will introduce a simple and effective identification method originally invented: The plastic film test method. Whether in the office, on the production floor or on the job site, you can test it yourself.
The first step is to squeeze the silicone sealant sample on the plastic film and scrape it flat so that it has a larger contact area with the plastic film.
In the second step, wait for 24 hours and observe the shrinkage of the plastic film. The greater the amount of mineral oil filled, the shorter the shrinkage time of the plastic film and the more obvious the shrinkage phenomenon.
This is the end of our discussion with you in this issue of SIWAY News. Now, do you have a deeper understanding of oil-extended sealant?
In order to make doors, windows and curtain walls safer and people's lives better.
Choose high-quality sealant products and stay away from "Oil-extended Sealant"!
Post time: May-19-2023