Quality identification of polymer skin covering templates

polymer skin covering formwork is a covering layer made of polymer materials, which is usually used in building construction, especially in the concrete pouring process. Made of polymer materials, which may include plastic, rubber or other synthetic materials, with good wear resistance, corrosion resistance and weather resistance. Polymer skin covering formwork has been widely used in modern building construction due to its high efficiency, environmental protection and economical characteristics.
A court commissioned Zhongke Testing to identify whether the covering formwork made of the "polymer skin" involved in the case had problems such as difficulty in removing the formwork, peeling of the skin, short service life, uneven concrete surface after the formwork was removed, and their causes.
It is understood that the supply and demand parties have signed multiple "Purchase Agreements", in which the size specifications and acceptance requirements are agreed upon.
The polymer skin supplied by the supplier and the formwork board produced by the demander are combined to form a building formwork. During actual construction at the construction site, the "polymer skin" involved in the case will be damaged to varying degrees after demoulding, and will fall off the board and adhere to the cement wall, so the desired demoulding effect cannot be achieved.
The demand side believes that the polymer skin products provided by the supplier cannot meet the demand side's requirements for the production of building templates. Its calcium powder content, non-woven fabric thickness, moisture content and other factors reduce the turnover rate of the "polymer skin" involved in the case. The supplier of
believed that the "polymer skin" involved in the case was adhered to the template board through glue and hot pressing. During the bonding and hot pressing process, the buyer did not know the technical details such as the glue brushing method, hot pressing temperature, operating environment, and processing technology. Therefore, it cannot be ruled out that during the process of making the "polymer skin" involved in the case into a concrete formwork, the performance of the "polymer skin" involved in the case has changed due to problems with the buyer's own process, or that the peeling of the skin is due to problems in the process of gluing the formwork boards and skin.

In order to find out the problem, the identification expert team and technical personnel first went to the site where the "polymer skin" involved was used to conduct surveys and samples.
Subsequently, the identification expert team and technical personnel reviewed the process documents for making the covering template from the "polymer skin" involved, the damage to the relevant covering template, the storage conditions of the polymer skin, the storage conditions of the finished covering template, and other information. They produced covering template samples for testing in accordance with the above process flow, and commissioned an inspection agency to conduct corresponding tests on the covering template samples.

1. The non-woven fabric layer of the "polymer skin" involved in the case has obvious uneven thickness. The uneven thickness of the non-woven fabric layer will lead to uneven bonding strength between the covering formwork and the concrete, which can easily cause the "polymer skin" involved in the case to be pulled or pulled off the concrete surface in whole or in part;
2. The calcium powder content and moisture content of the "polymer skin" involved in the case are relatively low, which should not have a significant impact on the barrier properties of the "polymer skin" involved;
3. When the purchaser made the "polymer skin" involved in the case into a covering formwork, it did not strictly follow the process documents provided by the supplier. Factors such as uneven gluing methods, too low a hot-pressing temperature, and excessive humidity in the operating environment would affect the bonding strength and stability between the covering formwork and concrete;
4. When the construction unit used the covering formwork made of the "polymer skin" involved in the case, it did not operate according to the specifications. There were improper use or overuse, such as premature form removal, excessive form removal force, too many form removal times, etc., which would accelerate the decline and failure of the bonding strength between the covering formwork and the concrete.
In summary, Zhongke Testing believes that the covering formwork made of the "polymer skin" involved in the case has problems such as difficulty in removing the formwork, skin peeling, short service life, and uneven concrete surface after the formwork is removed. The main reasons are:
● The uneven thickness of the non-woven fabric layer of the "polymer skin" involved in the case leads to insufficient strength;
● The purchaser's improper operation when making the "polymer skin" involved in the case into a covering formwork resulted in low bonding strength;
● The construction unit's improper operation when using the covering formwork made of the "polymer skin" involved in the case resulted in a decrease in its bonding strength.