Common putty powder raw material types and choices
1. heavy calcium carbonate
Calcium carbonate, the chemical formula is CaCO3, the sedimentation volume is 1.1-1.9ml/g, refer to as heavy calcium powder, belonging to natural carbonate minerals, using mechanical direct pulverization method, with good thermal stability (not decomposed below 4000C), inert Strong, good whiteness, low oil absorption, no crystal water, non-toxic, odorless, non-combustible, and good dispersion. After grinding into powder, 100 mesh or less, commonly known as single fly powder, more than 200 mesh is commonly known as double fly powder, more than 1250 mesh is call ultrafine powder.
2. hydroxypropyl methyl cellulose ether (HPMC)
HPMC has high viscosity (200,000-200,000), good water solubility, no impurities, and better stability than sodium carboxymethyl cellulose (CMC). Due to factors such as lower price of raw materials, overcapacity, and increased market competition, the market price of HPMC is high. The price is falling, and the current price is 17,000-26,000 yuan / ton.
Because of the small amount of addition, the cost is not much different from that of CMC. HPMC can be use instead of CMC to improve the quality and stability of ordinary putty. Quality and identification of hydroxypropyl methylcellulose ether (HPMC).
3. Sodium Carboxymethyl Cellulose (CMC)
Sodium carboxymethyl cellulose (CMC) has a viscosity of between 300 and 8000. The viscosity of CMC for common putty is about 400. At present, the CMC products on the market are mix. Some manufacturers and merchants add stone powder to CMC products, which seriously affects the quality of CMC.
It is easy to detect the stability of the precipitate (stone powder) and the aqueous solution by using the aqueous solution test and observation method. Therefore, the high quality putty powder should be use with caution.
4.pre-gelatinized starch
The starch granules enter the ripening and gelatinization at a temperature of 60-80 °C. When the gelatinize starch is in contact with water, the hydrogen bonds between the molecules are broke, and gradually swell, split, and form a uniform paste solution. The pre-gelatinized starch is simple to process, and is also call modified starch, alpha-starch, and soluble alpha-starch.
Due to price competition, it is also common to add stone powder to pre-gelatinized starch products. It is easy to detect precipitates (stone powder) by using aqueous solution experiments and observation methods.
From the seal storage of the pregelatinized starch aqueous solution, it is seen that the stability of the pre-gelatinized starch quality is not very good. Therefore, ordinary high-quality putty powder should be use with pre-gelatinized starch.
5. carboxymethyl starch (CMS)
Carboxymethyl starch (CMS) is mainly made up of corn starch, sodium hydroxide (NaOH, commonly known as caustic soda), monochloroacetic acid, etc. by gelatinization and etherification. Observe from the seal storage of CMS aqueous solution, it is see that the stability of CMS quality is not very good. Therefore, ordinary high quality putty powder should be use with caution.
6, HYM-2 plant type dispersible rubber powder
HYM-2 is a high-quality plant-type dispersible rubber powder. It has the characteristics of environmental protection, health, stability, anti-aging and high bonding strength. The binding strength of the aqueous solution is 1.1Mpa at 10% concentration. .
7. bentonite
Bentonite is a smectite-based hydrous clay mine. Due to its special properties such as swelling, cohesiveness, adsorption, catalytic, thixotropic, suspension and cation exchange, it is use in interior wall putty. Appropriate addition can increase the consistency of the putty, thixotropy, ease of application of the coating, and the like.
8.native kaolin
Clay-based materials, with natural active ingredients, strong gelling ability, so stable gel state, and its viscosity can be keep for a long time (the viscosity and gel state of the soil can be eternal).
In ordinary putty products, proper addition of uncalcined, high whiteness, fine hand feeling, good viscosity kaolin, so mica powder or other types of clay can effectively improve the quality, construction operation and stability of the putty.
9.hydroxypropyl starch ether (HPS)
Hydroxypropyl starch ether (HPS) is a chemically modify starch that is etherification by propylene oxide and starch to replace the hydroxyl groups in the starch polymer structure to form an etherification starch. Viscosity of hydroxypropyl starch ether (HPS) (5% aqueous solution, 20 ° C): 500-20000 mPa.s.
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