Why should we add HPMC to putty powder?

HPMC can be used in food, pharmaceutical, construction, and daily necessities industries, etc. In construction, 90% of HPMC is used in putty.

Role of HPMC in putty powder

In putty powder, HPMC mainly plays three roles: thickening, water retention, and construction, among which the most important role is water retention.

Thickening: cellulose can be thickened to play the role of suspension so that the solution maintains a uniform up and down. Adding HPMC in putty powder can increase the consistency of the solution, make the putty uniform, and play the role of anti-flowing and hanging.

Water retention: HPMC has the function of water retention, which can make the putty powder dry slower and assist the reaction of grey calcium under the action of water.

Construction: Cellulose has a lubricating effect, which can make the putty powder have good constructibility.

In this process, HPMC is not involved in any chemical reaction, only playing a supporting role. Putty powder with water, on the wall, is a chemical reaction, because there is the generation of new substances. So getting the putty powder off the wall, grinding it into powder, and using it again, won’t work, because a new substance (calcium carbonate) has been formed.

Putty may appear to problems and solutions

Putty off powder

Phenomenon:

After the construction is finished and dry, there is powder falling off when touching with hands.


Solution

  1. The internal wall putty surface polishing to master the appropriate polishing time, polishing the best period is for be putty surface watermark to disappear, immediately after polishing. The practice has proved that the finish 1~2 ㎡ should be pressed flat or polished.
  2. After drying the surface of the exterior wall putty, it should be moderately polished and fully drenched with water for maintenance, and the general maintenance is divided into two or more than two times, the effect will be better.
  3.  It is recommended to add HPMC additives to putty powder to improve the water retention and ease of putty powder, the quality of putty powder will be significantly improved, and can also add re-dispersible polymer powder (RDP) to enhance the adhesive force.

Putty falling off

Phenomenon:

Poor bonding strength between putty and grass-roots level, falling off directly from the grass-roots level.


Solution:

  1. shovel out the shedding layer, according to the following situation targeted treatment;
  2.  Polish the old wall surface to increase the surface roughness, then, use the interface agent (10% environmental protection glue or interface agent treatment);
  3. Use an oil-removing cleaning agent to get rid of the surface of the release agent or other grease components, and then apply scraping putty.
  4. Use special plywood putty for construction.
  5. Marble, mosaic, tiles, and other external surfaces, please choose the exterior wall renovation putty priming.
  6. Add HPMC powder in the putty to increase the adhesion of the putty.

Putty cracking

Phenomenon:

Putty construction for a period of time, the surface cracking.


Solution:

  1. Has cracked putty, needs to shovel, if the crack is not too big, can also use flexible putty for the first construction, and then according to the specification of the construction method.
  2. Each construction should not be too thick, two construction time intervals must be greater than 4 hours or more, and the former putty thoroughly dry before the latter scraping.

Putty blistering

Phenomenon:

Air bubbles are generated during construction and after a period of time, the surface of putty blisters.

Solution:

  1. The appearance of the large blistering putty surface, with a spatula directly pressed through the mouth of the small bubbles, and re-use the appropriate putty to scrape the blistering surface layer.
  2. Putty is generally in the mixing, after resting for about 10 minutes, and then use the electric mixer again after mixing on the wall.
  3. Construction of the second or last surface layer of blistering phenomenon, should be in the watermarks before the elimination of the squeegee pressure bubble breaking treatment, to ensure that the putty surface does not appear bubbles.
  4. Especially rough wall surfaces, general primer as far as possible to choose coarse putty.
  5. If the wall is too dry or windy light a strong environment, first as much as possible with water to wet the wall, to be no water after the wall, putty layer scraping.

Putty powder turns yellow

Phenomenon:

It refers to the yellow color of the putty in part or in whole soon after the construction is finished.

 
Solution:

  1. With environmental protection glue roll coating two times, thoroughly dry, and then scrape the interior wall putty;
  2. Roll coating two times with sealing primer, dry thoroughly, and then scrape putty.
  3. All use paste putty construction or use sheet putty construction.

Putty delamination

Phenomenon:

Between two layers of putty or between putty and substrate are peeled off from each other.


Solution:

  1. Shovel out the shedding layer, and re-select the special putty scraping;
  2. For serious chalking of the construction surface, it is best to use 10% closed primer dilution for sealing, to be dry, and then the corresponding putty layer or other construction ;
  3. Putty, especially the interior wall putty, as far as possible to shorten the interval between the two putty construction;
  4. Pay attention to the construction process protection, in the process of putty construction or construction within 8 hours after the putty is best not to be wet with water;

The effectiveness of HPMC powders varies at different temperatures and PH. To make HPMC work better in putty and enhance the performance of putty, contact us now for expert guidance!

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