Cellulose ethers, especially hypromellose ethers, are important components of commercial mortars. For cellulose ether, its viscosity is an important index of mortar production enterprises, high viscosity has almost become the basic demand of mortar industry. Due to the influence of technology, process and equipment, it is difficult to guarantee the high viscosity of domestic cellulose ether products for a long time. Cellulose ether is used as water-retaining agent, thickener and binder in mortar products, which has great influence on the operating performance, wet viscosity, operating time and construction mode of mortar system. These functions are mainly accomplished by the hydrogen bond between cellulose ether molecule and water molecule and the winding action of cellulose ether molecule, in fact, it takes up part of the hydrogen bond in the cellulose ether molecular chain and weakens the entanglement of cellulose ether, which weakens the water retention and wetting ability of cellulose ether. Mortar manufacturers mostly do not feel this point, on the one hand, the domestic mortar products are still relatively rough, have not yet been careful to pay attention to the stage of operating performance, on the other hand, we choose the viscosity is much higher than the technical required viscosity, this part also compensated for the loss of water retention, but in the wettability is damaged.
The performance of mortar is influenced by cellulose ether containing adhesive extractant in production process, in this paper, the difference of tensile adhesive strength between cellulose product and cellulose ether product added with tackifier in ceramic tile adhesive was verified by experiments. Tackifier is a kind of material added by some cellulose ether manufacturers in order to make up for the shortage of production technology, technology and equipment. The existence of tackifier makes the long chain molecules of cellulose ether cross-link and become net-like, which affects the speed of cellulose ether film formation and the state of the film, thus affecting the role of cellulose ether in mortar, the direct-viewing influence is: the tensile adhesive strength has changed under each curing condition; the setting time of mortar is prolonged.
1.Under the standard curing condition, the addition of tackifier and cellulose ether without tackifier in the production process has a certain effect on the tensile adhesive strength of ceramic tile adhesive, the products added with tackifier in the production process have relatively high tensile adhesive strength.
2.In the aspect of water resistance, the tensile adhesive strength of the ceramic tile adhesive with cellulose ether added tackifier in the production process is worse than that of the product without tackifier in the normal production process, the cellulose ether containing tackifier affects the water resistance of tile adhesive.
3.In terms of air setting time, cellulose ether with tackifier was used in tile adhesive, its tensile adhesive strength was lower than that of the product without tackifier, and the opening time was shortened.
4.As for setting time, the curing speed of cellulose ether ceramic tile adhesive without adding tackifier under normal production process is faster. In summary, the presence of a tackifier, the cross-linking action of which makes the cellulose ether aqueous solution have a higher steric hindrance, which is shown to be higher in the test, but the existence of tackifier affects many important application properties of cellulose ether, such as water resistance, opening time, wettability and so on. In fact, viscosity is only one of the performance indexes of cellulose ether, viscosity is not an important index for the comprehensive performance of cellulose ether, but the type and content of groups should be the focus of mortar manufacturers.
5.It is also because the mortar manufacturers pay too much attention to viscosity, prompting some cellulose ether production enterprises to increase viscosity through additional materials to meet the requirements of mortar manufacturers, and this type of products only have a high apparent viscosity, its comprehensive performance is worthy of users' attention, and the apparent high viscosity formed by increasing viscosity can not achieve the“High viscosity low content” theory which mortar manufacturers expect, but does not exist in fact. In order to select cellulose ether, which is an important raw material in mortar, the mortar enterprises pursuing high and stable quality need to know some information behind, this will be conducive to manufacturers to develop high-performance products, to ensure product quality stability.
Post time: Jul-17-2023