Properties that glass yarn that has good correlation with plastering glue should have

1.Higher node strength
If the nodes slip when the glass yarn is stretched, the stress in the initial stage will be mostly borne by the plastering glue and cracks will occur.

The test method for node strength is: cut a 330mm×50mm test strip along the weft direction, and cut off all the woven yarns on both sides about 150mm from the end of the test strip, leaving only one weft yarn in the middle; nodes), cut the weft yarn in the middle. Put the test strip on a tensile machine for a tensile test. One end of the testing machine clamps the weft yarn, and the other end clamps all the yarns. Read the force (N) of pulling out the yarns. The external wall insulation system generally requires the node strength of the glass yarn to be ≥3.0N/single wire.

2. Lower tensile strain
If the nodes do not slip when the glass yarn is stretched, but the stretching strain is large, it will also cause the plastering glue to crack at an early stage.
The tensile strain of the glass yarn includes the strain in the early stage of tension and the strain at fracture. It can be expressed by the tensile force when the elongation is 0.25%, 0.5%, and 1.0%, as well as the tensile force (breaking strength) and breaking strain at break.
3. Smaller yarn deflection
When Fiber Glass is weaved, it is inevitable that the yarn will go astray. If it deviates too much, it will cause eccentricity when receiving force, which will also affect the use effect. Generally speaking, within a length of 1m, the deflection of the woven wires shall not exceed 3 woven wires.
In terms of performance matching, the elasticity (cracking strain) of plaster mortar should be as high as possible, while the opposite is true for glass yarn. According to testing, the fracture strain of Fiber Glass from some domestic manufacturers is around 5%, while the cracking strain of cement-based plaster mortar is only 0.4%-0.5%.
The cracking strain of cement-free pure polymer plastering glue is relatively high. For example, the high elastic fiber-reinforced plastering glue of Shendeou exterior wall insulation system can reach 2.38%. When combined with a glass yarn with a breaking strain of less than 3.5%, Its excellent anti-cracking properties are obvious.
In order to give full play to the tensile properties of the glass yarn, it should be noted that the position of the glass yarn should be at the outer 1/3 of the thickness of the entire protective surface layer during construction. When constructing the external wall insulation system, it is better if the grid of the Fiber Glass can be seen on the surface of the plaster but not the color of the Fiber Glass.