The application of latex powder in new flexible putty

Putty is a flexible putty modifie by a variety of additives. When it is mixed with water, the dry powder powder meets water to form a polymer emulsion. And in the drying process, the emulsion dehydrated again to form a composite system of stereo mesh structure. Therefore, the effect of latex powder in putty is affecte by the cement hydration and film formation process of latex powder.

The formation process of the composite system is complete in four steps:
  • When the putty is mix with water, dry powder latex powder in water dispersed into small particles of polymer emulsion:
  • In the initial stage of cement hydration, cement gel formed in the hydration process of cement. Saturate, and the polymer particles forme by latex powder are deposite on the surface of cement gel / unhydrate cement particle mixture
  • As the cement is further hydrate. The water in the pores is constantly decreasing, and the polymer particles are gradually confine to the pores. Forming a tight accumulation layer on the cement gel / unhydrated cement particle mixture and the packing surface.
  • Under the action of hydration reaction, base absorption and surface evaporation, the water in the system is further reduce. And the polymer pushing layer gathers into a thin film. And the hydration reaction products are bonde to form a complete stereo mesh structure. Therefore, the composite system is forme by the cement hydration process and the film-forming process of the latex powder.

From the point of practical engineering application, as external insulation system surface transition layer putty. Its strength should not be higher than plastering mortar, otherwise prone to cracking phenomenon. In the whole external wall insulation system, putty flexible should be higher than the substrate flexible. So that putty can better adapt to the substrate deformation.

  • (1) A new flexible putty for external insulation system is prepare by dispersing latex powder and other raw materials.
  • (2) The putty has good bonding strength (standard state 1.35MPa, 1.00MPa after 8 freeze-thaw cycles). Low water absorption (1.0g / 10min) and high dynamic cracking resistance (0.34mmn).
  • (3) The mixing amount of dispersed latex powder has a great impact on the flexibility of the putty. When the ash ratio is 14%, the putty can obtain the ideal flexibility.


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