1. Hydroxypropyl methyl cellulose HPMC has stable chemical properties, mildew-proof and water-retaining effects in the glue, and is not affected by changes in pH. The viscosity can be used from 100,000 S to 200,000 S. However, in production, the higher the viscosity, the better. The viscosity is inversely proportional to the bonding strength. The higher the viscosity, the lower the strength. Generally, a viscosity of 100,000 is appropriate.
2. In the glue, the fast-dissolving hydroxypropyl methyl cellulose HPMC must be used, because the hydroxypropyl methyl cellulose HPMC is only dispersed in water without real dissolution. In about 2 minutes, the viscosity of the liquid gradually increased, forming a transparent viscous colloid. Hot-melt products, when they come together in cold water, can quickly disperse in hot water, and disappear in hot water. When the temperature drops to a certain temperature, the viscosity slowly appears until a transparent viscous colloid is formed. The recommended amount of hydroxypropyl methylcellulose HPMC in the glue is 2-4kg.
3. The glue layer problem is a bigger problem encountered by customers. First of all, the construction glue layer must consider the problem of raw materials. The main reason for the glue layer is the incompatibility of polyvinyl alcohol and hydroxypropyl methylcellulose HPMC. The second reason is that the mixing time is not enough; the other is that the thickening performance of the construction glue is not good.