Innovation in the production process of redispersible latex powder

Redispersible polymer powder (RPP) is an important building material additive, widely used in dry-mixed mortars of various cement-based, gypsum-based and other base materials. Its production process directly affects its performance and application effect.

1. Selection and pretreatment of raw materials

1.1 Selection of raw materials

The main component of redispersible latex powder is polymer latex, usually including ethylene-vinyl acetate copolymer (EVA), ethylene-acrylate copolymer (VAE), etc. Traditional raw materials are often limited to the use of conventional monomers, such as ethylene, vinyl acetate, etc.

Innovation points

1.1.1 Introduction of new monomers: The use of acrylate monomers, fluoroolefin monomers, etc. can improve the weather resistance and adhesion of latex powder. These monomers can improve the physical and chemical properties of polymers by crosslinking or copolymerization.

1.1.2 Environmentally friendly monomers: With the increasing environmental protection requirements, choosing low volatile organic compounds (VOC) or non-toxic monomers can reduce environmental pollution and improve product safety. For example, using bio-based monomers (such as lactic acid esters) instead of petroleum-based monomers.

1.2 Pretreatment technology

In order to ensure the final performance of latex powder, the pretreatment of raw materials is very critical. Traditional pretreatment methods may include physical stirring or chemical modification.

Innovation points

1.2.1 Plasma treatment: Plasma treatment improves the surface energy of the monomer, making it easier to mix and react with other components.

1.2.2 Ultrasonic treatment: Ultrasonic waves can effectively disperse and homogenize latex, improve the particle size distribution of latex, and improve the dispersibility and stability of latex powder.

2. Innovation of emulsion polymerization process

2.1 Polymerization method

Traditional emulsion polymerization methods include emulsion polymerization, microemulsion polymerization and suspension polymerization. These methods usually require the use of emulsifiers and stabilizers to maintain the stability of the emulsion.

Innovations

2.1.1 Controlled radical polymerization: The introduction of controlled radical polymerization methods such as atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization can accurately control the molecular weight and structure of the polymer, thereby improving the performance of latex powder.

2.1.2 Environmentally friendly polymerization: The use of water-soluble initiators and degradable emulsifiers can reduce environmental pollution and harmful substances remaining in the product. Efficient water phase system can also reduce energy consumption and production costs.

2.2 Polymerization equipment and process control

Modern production equipment and precise process control can significantly improve production efficiency and product quality.

Innovations

2.2.1 Reactor automation control: By introducing an intelligent control system, fully automatic control of the polymerization reaction is achieved, including real-time monitoring and adjustment of parameters such as temperature, pressure, and stirring speed.

2.2.2 Microchannel reactor: The use of microchannel reactors for polymerization reactions can improve mass transfer and heat transfer efficiency, reduce by-product generation, and improve product consistency and quality.

3. Optimization of spray drying technology

3.1 Traditional spray drying

Spray drying is a key step in converting emulsion into powder. Traditional spray drying methods may face problems such as uneven particle size distribution and poor product fluidity.

Innovation

3.1.1 Airflow spray drying: Using high-speed airflow spray technology, more uniform atomization and finer particle size can be achieved, improving the dispersibility and redispersibility of latex powder.

3.1.2 Multi-stage spray drying: Through the multi-stage drying tower design, the humidity and temperature are gradually reduced to achieve a more efficient drying process and avoid the problem of powder agglomeration caused by rapid drying.

3.2 Upgrade of drying equipment

Innovation

3.2.1 Cyclone separator optimization: The introduction of high-efficiency cyclone separators can more effectively separate powder and waste gas, reduce dust emissions and product losses.

3.2.2 Heat recovery system: Through the heat recovery system, waste heat in the drying process is recycled to improve energy efficiency and reduce production costs.

4. Post-processing and packaging technology

4.1 Powder surface treatment

In order to improve the storage stability and performance of redispersible latex powder, surface treatment is often required.

Innovation

4.1.1 Nanomaterial coating: Using nanomaterials to coat the surface of latex powder can significantly improve its water resistance and wear resistance.

4.1.2 Surfactant treatment: Select appropriate surfactants to treat latex powder to improve its dispersibility and redispersibility in water.

4.2 Packaging technology

Innovation

4.2.1 Nitrogen packaging: Using nitrogen packaging can reduce the impact of oxidation and humidity on latex powder and extend its shelf life.

4.2.2 Degradable packaging materials: Using environmentally friendly degradable packaging materials not only meets the requirements of sustainable development, but also reduces pollution to the environment.

5. Product application and performance improvement

5.1 Performance improvement

Through the above process innovation, the performance of redispersible latex powder has been significantly improved in the following aspects:

5.1.1 Weather resistance: The improved latex powder has better weather resistance and can maintain stable performance under harsh environmental conditions.

5.1.2 Adhesion: The adhesion performance of latex powder has been significantly improved by optimizing polymer structure and surface treatment technology.

5.1.3 Dispersibility: The application of new spray drying technology and surfactants makes latex powder have better dispersibility and stability in water.

5.2 Application scope expansion

5.2.1 New building materials: Redispersible latex powder is widely used in high-performance cement-based and gypsum-based dry-mixed mortars, including self-leveling floors, thermal insulation mortars and other new building materials.

5.2.2 Repair materials: Due to its excellent adhesion and flexibility, redispersible latex powder is also widely used in building repair materials.

The production process of redispersible latex powder is constantly innovating to meet market demand and environmental protection requirements. From raw material selection to polymerization process, from drying technology to post-processing, innovation in every link has significantly improved product performance and application value. In the future, through continuous technological progress and process optimization, redispersible latex powder will further play its important role in the field of building materials and promote the green and sustainable development of the industry.