Hydroxypropyl Starch Ether Building Chemical Additive

Hydroxypropyl Starch Ether (HPS) is a chemically modified natural plant starch derivative, commonly used in building chemical additive systems. As a highly efficient functional additive, it is widely used in building materials such as dry-mixed mortar, plaster mortar, tile adhesive, gypsum-based products, self-leveling materials and thermal insulation mortar. Its main functions include improving construction performance, adjusting consistency, improving water retention and anti-sagging properties, and enhancing the construction adaptability of mortar and the quality of the final product.

Basic properties of hydroxypropyl starch ether

Hydroxypropyl starch ether is a non-ionic modified starch ether prepared by introducing hydroxypropyl groups into natural starch molecules. It is stable in alkaline and neutral environments and exhibits excellent rheological adjustment ability and construction friendliness in mortar. Compared with other additives (such as cellulose ethers), hydroxypropyl starch ether has a better balance between cost and performance.

Its main physical properties are as follows:

Appearance: white to slightly yellow fine powder;

Water solubility: dissolved in cold water to form a stable colloid;

pH stability: suitable for systems with pH 6-12;

Thermal stability: adapt to high temperature construction conditions;

Compatibility: well compatible with cement, gypsum, lime calcium and most polymers.

The main role of hydroxypropyl starch ether in construction chemicals

2.1. Improve construction performance

HPS significantly improves the lubricity and construction fluidity of mortar, making it easier to apply, flatten and finish, thereby improving construction efficiency. Especially in plaster mortar and leveling layer, it can reduce tool resistance and make construction smoother.

2.2. Enhance water retention

Although the water retention effect of HPS is slightly lower than that of high-end cellulose ether, adding an appropriate amount of HPS to low- and medium-end dry-mixed mortar systems can effectively improve the water retention of mortar, prevent excessive water loss, and reduce problems such as cracking and hollowing caused by excessive water loss.

2.3. Improve anti-sagging property

In vertical construction occasions such as tile adhesive and plaster mortar, HPS significantly improves the anti-sagging ability of materials by enhancing bonding strength and improving yield stress, preventing materials from sliding or sagging, and improving construction safety and molding quality.

2.4. Control consistency and thixotropy

HPS can effectively adjust the consistency of mortar at a low addition amount, so that the slurry has good thixotropic properties, that is, "thick when standing, thin when stirred", which is convenient for construction and finishing, and helps to control thickness and surface smoothness.

2.5. Improve system stability

When HPS is used in conjunction with other additives (such as cellulose ether and redispersible latex powder), it has good stability, can help stabilize polymer emulsions, and improve the overall bonding performance and flexibility of mortar.

Application fields and recommended addition amounts

3.1. Tile Adhesive

Improve water retention and anti-slip properties, improve operability time, recommended addition amount: 0.05–0.2%.

3.2. Render Mortar

Improve lubricity and construction fluidity, improve construction efficiency, recommended addition amount: 0.05-0.3%.

3.3. Self-Leveling Mortar

Adjust rheology, avoid sedimentation, and improve stability, recommended addition amount: 0.03-0.15%.

3.4. Gypsum-based Mortar

Prevent water seepage, extend open time, and improve surface effect, recommended addition amount: 0.05-0.2%.

3.5. Thermal insulation mortar/polymer mortar

Coordinate the thixotropy and workability of mortar, improve interface bonding, recommended addition amount: 0.05-0.2%.

Cooperation with other construction additives

Hydroxypropyl starch ether is usually not used alone, but is used together with cellulose ether, latex powder, defoamer, water reducer, etc. to form a formula system. Among them, HPS can be used as a "regulator" to help control the overall rheological properties, optimize the construction feel, reduce the amount of cellulose ether, and thus reduce costs.

Synergize with HPMC/HEMC to improve water retention;

Combine with redispersible latex powder to enhance adhesion and flexibility;

Synergize with defoamers to control air entrainment.

As a highly efficient building additive, hydroxypropyl starch ether has the advantages of low cost, small addition amount, and stable performance. It is particularly suitable for economical and mid-range building dry powder material systems. With the promotion of green building materials and energy-saving and environmental protection concepts, the environmental protection and natural source advantages of hydroxypropyl starch ether will be more valued. In the future, through more precise molecular structure control and coordinated design with other additives, the application potential of HPS in high-performance building materials will be further released. It will not only be limited to construction auxiliary functions, but may also participate in the development of new products such as functional mortars such as thermal insulation, heat insulation, and water resistance.