Abstract: This paper explores the influence and law of cellulose ether on the main properties of tile adhesives through orthogonal experiments. The main aspects of its optimization have certain reference significance for adjusting some properties of tile adhesives.
Nowadays, the production, processing and consumption of cellulose ether in my country are in the leading position in the world. The further development and utilization of cellulose ether is the key to the development of new building materials in my country. With the continuous development of tile adhesives and the continuous optimization and improvement of their performance, the selection of mortar application types in the new building materials market has been enriched. However, how to further optimize the main performance of tile adhesives has become the development of the tile adhesive market. new direction.
1. Test raw materials
Cement: The P.O 42.5 ordinary Portland cement produced by Changchun Yatai was used in this experiment.
Quartz sand: 50-100 mesh was used in this test, produced in Dalin, Inner Mongolia.
Redispersible latex powder: SWF-04 was used in this test, produced by Shanxi Sanwei.
Wood fiber: The fiber used in this test is produced by Changchun Huihuang Building Materials.
Cellulose ether: This test uses methyl cellulose ether with a viscosity of 40,000, produced by Shandong Ruitai.
2. Test method and result analysis
The test method of tensile bond strength refers to the standard JC/T547-2005. The size of the test piece is 40mm x 40mm x 160mm. After forming, let it stand for 1d and remove the formwork. Cured in a constant humidity box for 27 days, bonded the drawing head with the test block with epoxy resin, and then placed it in a constant temperature and humidity box at a temperature of (23±2)°C and a relative humidity of (50±5)%. 1d, Check the sample for cracks before the test. Install the fixture to the universal electronic tensile testing machine to ensure that the connection between the fixture and the testing machine is not bent, pull the specimen at a speed of (250±50) N/s, and record the test data. The amount of cement used in this test is 400g, the total weight of other materials is 600g, the water-binder ratio is fixed at 0.42, and an orthogonal design (3 factors, 3 levels) is adopted, and the factors are the content of cellulose ether, the content of rubber powder and the ratio of cement to sand , according to the previous research experience to determine the specific dosage of each factor.
2.1 Test results and analysis
In general, tile adhesives lose tensile bond strength after water immersion.
From the test results obtained by the orthogonal test, it can be found that increasing the amount of cellulose ether and rubber powder can improve the tensile bond strength of the tile adhesive to a certain extent, and reducing the ratio of mortar to sand can reduce its tensile bond strength, but the test result 2 obtained by the orthogonal test cannot more intuitively reflect the impact of the three factors on the tensile bond strength of the ceramic tile adhesive after soaking in water and the tensile bond after 20 min of drying. Therefore, discussing the relative value of the decrease in tensile bond strength after immersion in water can better reflect the influence of the three factors on it. The relative value of the decrease in strength is determined by the original tensile bond strength and the tensile strength after immersion in water. The ratio of the difference in bond strength to the original tensile bond strength was calculated.
The analysis of the test data shows that by increasing the content of cellulose ether and rubber powder, the tensile bond strength after immersion in water can be slightly improved. The bonding strength of 0.3% is 16.0% higher than that of 0.1%, and the improvement is more obvious when the amount of rubber powder is increased; When the amount is 3%, the bonding strength increases by 46.5%; by reducing the ratio of mortar to sand, the tensile bond strength of immersion in water can be greatly reduced. Bond strength decreased by 61.2%. It can be seen intuitively from Figure 1 that when the amount of rubber powder increases from 3% to 5%, the relative value of the decrease in bond strength increases by 23.4%; the amount of cellulose ether increases from 0.1% to In the process of 0.3%, the relative value of bond strength decrease increased by 7.6%; while the relative value of bond strength decrease increased by 12.7% when the ratio of mortar to sand was 1:2 compared with 1:1. After comparison in the figure, it can be easily found that among the three factors, the amount of rubber powder and the ratio of mortar to sand have a more obvious influence on the tensile bond strength of water immersion.
According to JC/T 547-2005, the drying time of tile adhesive is greater than or equal to 20 min. Increasing the content of cellulose ether can make the tensile bond strength gradually increase after airing for 20 minutes, and the content of cellulose ether is 0.2%, 0.3%, compared with the content of 0.1%. The cohesive strength increased by 48.1% and 59.6% respectively; increasing the amount of rubber powder can also make the tensile bond strength gradually increase after airing for 20rain, the amount of rubber powder is 4%, 5% % compared with 3%, the bond strength increased by 19.0% and 41.4% respectively; reducing the ratio of mortar to sand, the tensile bond strength after 20 minutes of airing decreased gradually, and the ratio of mortar to sand was 1:2 Compared with the mortar ratio of 1:1, the tensile bond strength is reduced by 47.4%. Considering the relative value of the reduction of its bond strength can clearly reflect the influence of various factors, through the three factors, it can be clearly found that the relative value of the decrease of the tensile bond strength after 20 minutes of drying, after 20 minutes of drying , the impact of mortar ratio on tensile bond strength is no longer as significant as before, but the effect of cellulose ether content is more obvious at this time. With the increase of the content of cellulose ether, the relative value of its strength decrease gradually decreases and the curve tends to be gentle. It can be seen that cellulose ether has a good effect on improving the bonding strength of the tile adhesive after 20 minutes of drying.
2.2 Formula determination
Through the above experiments, a summary of the results of the orthogonal experimental design was obtained.
A group of combinations A3 B1 C2 with excellent performance can be selected from the summary of the design results of the orthogonal experiment, that is, the content of cellulose ether and rubber powder is 0.3% and 3%, respectively, and the ratio of mortar to sand is 1:1.5.
3. Conclusion
(1) Increasing the amount of cellulose ether and rubber powder can increase the tensile bond strength of the tile adhesive to a certain extent, while reducing the ratio of mortar to sand, the tensile bond strength decreases, and the ratio of mortar to sand The effect of the amount of cellulose ether on the tensile bond strength of the ceramic tile adhesive after immersion in water is more significant than the effect of the amount of cellulose ether on it;
(2) The amount of cellulose ether has the greatest influence on the tensile bond strength of the tile adhesive after 20 minutes of drying, indicating that by adjusting the amount of cellulose ether, the tile adhesive can be well improved after 20 minutes of drying. After tensile bond strength;
(3) When the amount of rubber powder is 3%, the amount of cellulose ether is 0.3%, and the ratio of mortar to sand is 1:1.5, the performance of the tile adhesive is better, which is the best in this test. Good level combination.
Post time: Feb-23-2023