HPMC for Wall Putty/ Skim Coat

The practice of neutral putty powder on the market in China

Neutral putty powder is classified according to the water retaining agent system
1. Use HPMC (currently very common) or HEMC (very few) as the water retention system
2. Use CMC as the water retention system (neutral water retention is good, but the price is high; alkaline water retention is almost poor, and the price is lower)
3. Composite water retention system with CMC as the main water retention and HPMC as the auxiliary water retention
4. Using CMC and CMS as a water retention system

The gelling material involved in the neutral putty powder
1. Polyvinyl alcohol powder (1788 or 2488)
2. Pregelatinized starch (tapioca or cornstarch and other pregelatinized starches)
3. Polyvinyl alcohol powder (1788 or 2488) compound pregelatinized starch

4. Polyvinyl alcohol powder (1788 or 2488) compound redispersible latex powder

5. Full use of CMC

6. Other types of vegetable gum powder

Putty powder of the following nine systems

1. Heavy calcium + CMC + (thixotropic agent, bentonite, starch ether,)

2. Heavy calcium + CMC + pregelatinization + (thixotropic agent, bentonite, starch ether,)

3. Heavy calcium + CMC (main) + HPMC (auxiliary) + pregelatinization + (thixotropic agent, bentonite, starch ether,)

4. Heavy calcium + CMC and CMS + (thixotropic agent, bentonite, starch ether,)

5. Heavy calcium + CMC and CMS + pregelatinization + (thixotropic agent, bentonite, starch ether,)

6. Heavy calcium + HPMC + pregelatinization + polyvinyl alcohol powder + (thixotropic agent, bentonite, starch ether)

7. Heavy calcium + HPMC + polyvinyl alcohol powder + (thixotropic agent, bentonite, starch ether,)
8. Heavy calcium + HPMC + polyvinyl alcohol powder + redispersible latex powder + (thixotropic agent, bentonite, starch ether,)
9. Heavy calcium + HPMC + common pregelatinization or vegetable glue + (thixotropic agent, bentonite, starch ether,)

The advantages and disadvantages of the above various systems of putty powder:
The first type: the advantage is that it is thick (good bottom cover), good adhesion and grinding, the disadvantage is that it is not resistant to ash calcium and cement, and it is easy to generate slag. The putty that has been stirred is easy to become bad (honeycomb) a lot of)

The second type: the advantage is that it is thick (good bottom cover), good adhesion and polishing, and the disadvantage is that it is not resistant to ash calcium and cement, and it is easy to generate slag

The third type: the advantage is that it is thick (good bottom cover), good adhesion and polishing, and the stability is better than the first two

The fourth and fifth types: similar to the first type of advantages and disadvantages

The above types are mostly used in the north of the central part of the country. The weather in the north is dry and the humidity of the wall is low, so it is not easy to mold and pulverize.

The sixth method: the current popular method has good stability, better anti-powdering resistance, outstanding advantages of putty, and high cost performance.

Seventh and eighth types: This system is the most alkali-resistant and mildew-proof neutral putty on the market, and it is mostly used in areas with humid weather such as Sichuan and Chongqing.

The ninth type: the current market is widely used, and it covers a wide range of areas, with high cost performance and good applicability.

Requirements for a good interior wall putty:
1. The first is to meet the national standards for interior wall putty
2. To meet the construction requirements of local workers: easy to scratch, good bottom cover, good plasticity, no return to thinning, easy to connect stubble, less foaming on the cast-in-place top after scraping, and the bottom cover is more important than the feel (scraped A lot of CMC putty with huge sales)
3. The water retention must be good, and the skin cannot be curled during the finishing process
4. The putty must be able to eat the thickness (cover the bottom) and not run away with the spatula. It is useless just to be smooth, and the bottom cover is the core.
5. To do the tearing test of the paint film, it must meet the requirements
6. There should be no yellowing spots (rust, you can add a magnet to each feed port, it is said to be effective)
7. The state of good putty: slippery (easy to scratch); soft (fluffy and tough, no sagging); cotton (good bottom covering), uniform and continuous
8. Both good construction and bottom covering (can not run spatula), high strength and good grinding
9. Grinding requirements: no broken skin, no delamination, less sand marks, good uniformity
10. Roll the latex paint without foaming

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