MHE227 - Hydroxy propyl methyl cellulose special for self-leveling mortar

Physico-chemical properties

Typical viscosity range of HUAMAO® HPMC products with NDJ-1 rotary viscometer at 20℃ with 2% solution.

Type	Typical viscosity
040	3-9
067	10-20
079	20-30
096	40-60
114	80-120
148	300-800
153	400-600
165	700-900
180	1200-2000
205	3500-5500
222	7000-9000
227	9000-11000
237	13000-17000
244	18000-22000
261	35000-45000
271	55000-65000
277	65000-85000
284	85000-130000
294	130000-180000
301	180000-230000
307	＞230000

*The above specifications have grade that disperses in cold water, such as MHE 227S, ”S” stands for dispersing in cold water

Physico-chemical properties of MHE227

Item	Required Specifications	Test Result
Appearance	White free-flowing power	White free-flowing power
hydroxypropoxy(WT%)	7.0-12.0	8.37
Methoxy(WT%)	28.0-30.0	28.56
Gel Temperature (℃)	58-64	58.5-60.0
Ash Content (%)	≤5	3.83
Moisture Content (%)	≤5	4.31
pH	5.0-8.0	7.55
Partical Size	Mesh 80	100% through
Viscosity (NDJ-1)	8000-12000	9200
Viscosity (Brookfield)	9200

2 % solution; Brookfield, on dry basis,20℃

Method for dissolution of hydroxypropyl methylcellulose

1. Hot water method: Because of hydroxypropyl methylcellulose insoluble in hot water, so early HPMC can be evenly dispersed in hot water, then cooling, two typical methods described as follows:
1) in the container into the required amount of hot water, and heating to about 70 ℃. Slowly stir with hydroxypropyl methylcellulose, start the hydroxypropyl methylcellulose floating on the surface of the water, and then gradually form a slurry, in the stirring to cool the slurry.
2) by adding 1/3 or 2/3 of the water required in the container and heating it to 70 ℃, by 1, disperse hydroxypropyl methylcellulose and prepare hot water slurry; then add the remaining amount of cold or ice water to the hot water slurry and cool the mixture after stirring.

2. Powder Mixing method: hydroxypropyl methylcellulose powder particles with equal or a larger number of other powdery ingredients, through dry mixing to fully disperse, then add water dissolved, then hydroxypropyl methylcellulose can be dissolved, but not condensed.

3. Organic solvent wetting method: hydroxypropyl methylcellulose with organic solvents, such as ethanol, ethylene glycol or oil in advance dispersion or wetting, and then add water dissolved, then hydroxypropyl methylcellulose can also be successfully dissolved.

Customization

HUAMAO® can customize according to customer demand, production of goods.
1. HUAMAO® can customize the packaging according to the customer's requirements.
2. HUAMAO® can produce HPMC which is the special technical index, according to the customer's demand.

Cellulose ether has the important influence on water retention, consistency and construction performance of self-leveling mortar. Especially as self-leveling mortar, fluidity is one of the main indexes to evaluate the performance of self-leveling. The fluidity of mortar in construction can be adjusted by changing the amount of cellulose ether to ensure the normal components of mortar. With the increase of the content of cellulose ether, the fluidity of mortar in construction decreased gradually, meanwhile, with the extension of the age, the dosage of cellulose ether must be controlled in a certain range, and the amount of excessive dosage would bring the negative effect on the fluidity of mortar. The water and cement in the mortar make up the pore of the sand grains, and the packing is lubricated around the sand grains, which makes the mortar have some fluidity. With the introduction of cellulose ether, the content of some free water in the system is reduced, and the coating layer of the outer wall of sand grains decreases, thus the fluidity of the mortar is reduced. Due to the high fluidity of self-leveling mortar, the dosage of cellulose ether should be controlled in the reasonable range.

Cellulose ether can improve the water retention of self-leveling mortar, and with the increase of the amount of cellulose ether, the water retention of mortar is gradually enhanced, while mortar fluidity and coagulation time are reduced, too high water retention will make the porosity increase in hardened slurry, which may make the compressive strength and flexural resistance of hardened mortar have obvious loss. When using cellulose ether, it is necessary to synthetically consider the mechanical properties of self-leveling Mortar, choose the dosage and its synergistic effect with other chemical materials rationally. The use of cellulose ether will reduce the compressive strength and flexural resistance of cement paste, which will improve the bonding strength of mortar. Analysis of the reasons for the change in strength, mainly micro products and structural changes caused, on the one hand, cellulose ether powder particles adsorbed on the surface of cement particles first, the formation of latex film, delaying the hydration of cement, which will lead to the early strength of the slurry loss; On the other hand, because of the film-forming effect and the effect of water retention, It is beneficial to the complete hydration of cement, which is beneficial to the increase of bonding strength. The author thinks that the change of these two kinds of strength mainly exists on the boundary of the coagulation period, the advance and delay of this boundary may be the critical point that causes two kinds of intensity magnitude, further systematic research this critical point, will be advantageous to the cement slurry in the hydration process of the control and analysis, It is advantageous to adjust the dosage and curing time of cellulose ether and improve the performance of mortar according to the demand of mechanical properties of mortar.