In the production process of putty powder, adding an appropriate amount of Hydroxypropyl Methyl Cellulose (HPMC) can improve its performance, such as improving the rheology of putty powder, extending the construction time, and increasing adhesion. HPMC is a common thickener and modifier, widely used in building materials, coatings, adhesives and other fields. For putty powder, adding HPMC can not only improve the construction performance, but also enhance the filling capacity and anti-cracking performance of putty.

 

The role of hydroxypropyl methylcellulose
Improving fluidity and construction performance: HPMC has a good thickening effect, which can improve the fluidity of putty powder, making the putty powder more uniform and less likely to flow when applied and repaired, and improving the efficiency and quality of construction.

 

Enhancing adhesion: The addition of HPMC can improve the adhesion between putty powder and the base material, avoiding problems such as putty powder falling off and cracking.

 

Improving water retention: HPMC can increase the water retention of putty powder, slow down the evaporation rate of water, thereby preventing the putty from drying and cracking, and helping the putty to maintain uniformity during the drying process.

 

Enhanced crack resistance: The polymer structure of HPMC can improve the flexibility of putty powder and reduce cracks caused by cracking, temperature changes or deformation of the base.

 

Amount of Hydroxypropyl Methylcellulose Added
Generally speaking, the amount of hydroxypropyl methylcellulose added is usually between 0.3% and 1.5% of the total weight of the putty powder, depending on the type of putty powder used, the required performance, and the requirements of the application.

 

Low viscosity putty powder: For some putty powders that require better fluidity, a lower HPMC addition amount can be used, usually around 0.3%-0.5%. The focus of this type of putty powder is to improve construction performance and extend the open time. Excessive HPMC may cause the putty powder to be too viscous and affect construction.

 

High viscosity putty powder: If the goal is to enhance the adhesion and crack resistance of the putty, or for walls with difficult base treatment (such as environments with high humidity), a higher HPMC addition amount may be used, usually 0.8%-1.5%. The focus of these putty powders is to improve adhesion, crack resistance and water retention.

 

Basis for adjusting the amount of addition
Use environment: If the construction environment has high humidity or low temperature, the amount of HPMC added is usually increased to improve the water retention and anti-cracking performance of putty powder.
Putty type: Different types of putty powder (such as interior wall putty, exterior wall putty, fine putty, coarse putty, etc.) have different requirements for HPMC. Fine putty requires more thickening effect, so the amount of HPMC used will be higher; while for coarse putty, the amount added may be relatively small.
Base condition: If the base is rough or has strong water absorption, it may be necessary to increase the amount of HPMC added to enhance the adhesion between the putty and the base.

 

Precautions for using HPMC

Avoid excessive addition: Although HPMC can improve the performance of putty powder, excessive HPMC will make the putty powder too viscous and difficult to construct, and even affect the drying speed and final hardness. Therefore, the amount of addition needs to be controlled according to specific needs.

 

Combination with other additives: HPMC is usually used in combination with other additives such as rubber powder, cellulose, etc. If it is used in combination with other thickeners or water retaining agents, attention should be paid to the synergistic effect between them to avoid performance conflicts.

 

Material stability: HPMC is a water-soluble substance. Excessive addition may cause the putty powder to absorb moisture and deteriorate during storage. Therefore, during production and storage, the amount of HPMC used should be considered to ensure the stability of the putty powder under normal storage conditions.

 

Adding HPMC to putty powder can significantly improve its performance, especially in terms of construction performance, water retention and crack resistance. Generally speaking, the addition amount of HPMC is between 0.3% and 1.5%, which is adjusted according to the needs of different types of putty powder. When using it, it is necessary to balance its thickening effect with construction requirements to avoid unnecessary effects caused by excessive use.