It is tough to use only a single cellulose ether to reach 30 minutes, and make the strength index reaches the standard. Only a few brands can achieve it, and the impact on the strength is also significant.If the single cellulose ether is above 3.5 and cannot be cooled for 30 minutes, then replace it. Generally, the average addition amount is wood fiber, redispersible polymer powder, starch ether, and it is not a problem to let it cool for 30 minutes.