Differences between surface treated and non surface treated Funahai HPMC products

Hydroxypropyl methylcellulose (HPMC) can be divided into two categories: surface treated HPMC and non surface treated HPMB. Surface treatment type, also known as delayed dissolution/hydration HPMC, refers to the use of crosslinking agents to treat its surface during production, allowing HPMC to quickly disperse in cold water without dissolving during this step. By stirring evenly, it will dissolve and the viscosity will slowly increase.
 
In contrast, untreated HPMC will clump in cold water, but quickly disperse when mixed with hot water. By stirring, the temperature of the solution will drop to a certain temperature (in our company, the gel formation temperature of the obtained product is about 65 ° C-75 ° C). The viscosity will increase slowly until a transparent, viscous gel is formed.
Differences between surface treated and non surface treated HPMC products
Untreated HPMC:
When untreated HPMC products dissolve separately, their particles quickly dissolve and form a thin film, causing water to no longer enter other particles, resulting in clumping and agglomeration.
The characteristic of untreated HPMC is that individual particles dissolve rapidly in neutral, alkaline, and acidic states. However, it cannot disperse between particles in the liquid, resulting in clumping and agglomeration.
In practical operation, this series of products, when physically dispersed with solid particles such as rubber powder, cement, and sand, will quickly dissolve without aggregation or clumping. Therefore, HPMC without surface treatment can be used for cement-based and gypsum grade tile adhesives, but cannot be used for paste lotion based tile adhesives.
HPMC surface treatment:
After surface treatment, HPMC product particles can be dispersed in neutral water without clumping, but will not immediately become sticky. After a period of immersion, the chemical structure of the surface treatment is destroyed, and water can dissolve HPMC particles. At this point, the product particles have completely dispersed and absorbed enough moisture, so the product will not clump or agglomerate after dissolution.
 
The characteristic of HPMC products with surface treatment is that the particles can be dispersed in an aqueous solution. It dissolves quickly in alkaline state and slowly in neutral and acidic state.
In actual production operations, this series of products often disperse and dissolve with other solid particulate matter under alkaline conditions. Its dissolution rate is no different from that of untreated products. During the construction process, both cement tile adhesive and gypsum based tile adhesive are alkaline systems, and the amount of HPMC added is very small. It can be evenly dispersed in these particles. HPMC quickly dissolves after adding water. Paste like latex tile adhesive is usually a neutral or slightly acidic product. Although using this series of products requires a certain amount of dissolution time, it is impossible to use HPMC without surface treatment to accelerate dissolution.
The physical and chemical properties of surface treated and non surface treated HPMC are the same, but their application fields are different. In short, delayed dissolution is commonly used for water-based substances such as detergents, cement, wet mortar, etc. Slowly dissolving HPMC needs to be added to the cement matrix at a content of 2%. Non delayed dissolution HPMC is our company's leading product. Delayed dissolution in neutral aqueous solutions will not become viscous within one to two hours, while non delayed dissolution in aqueous solutions will immediately become viscous. In one case, the viscosity onset time of slowly dissolving HPMC and non slowly dissolving Hydroxypropyl Methyl Cellulose is the same, that is, in alkaline solutions with a pH value less than 9. At this point, the application areas of the two HPMCs may overlap.