VAE redispersible powder

Vinyl acetate-ethylene copolymer (VAE) emulsion is the abbreviation of vinyl acetate-ethylene copolymer emulsion. It is a polymer emulsion formed by copolymerizing vinyl acetate and ethylene monomers with other auxiliary materials through emulsion polymerization.   White latex is a water-soluble adhesive, a thermoplastic adhesive produced by polymerization of vinyl acetate monomer under the action of an initiator. Usually called white latex or PVAC emulsion for short, the chemical name is polyvinyl acetate adhesive, which is synthesized from acetic acid and ethylene to vinyl acetate, with the addition of titanium dioxide (low-grade ones add light calcium, talc, and other powders). It is then made by emulsion polymerization. A thick milky white liquid.   VAE emulsion has the advantages of permanent softness, water resistance, low temperature resistance, fast bonding speed, high bonding strength, and is safe and non-toxic. VAE emulsion is widely used in adhesives, exterior wall insulation, building waterproofing, coatings, composite packaging materials, building cement mortar modification, non-woven fabric manufacturing, paper coating and general adhesive for various polar and non-polar materials. Access and other fields.   The characteristics of white latex include normal temperature curing, fast curing, high bonding strength, good toughness and durability of the bonding layer and not easy to age. White latex is a widely used water-soluble adhesive. It is mainly used in wood bonding, construction industry, coatings, etc. It is also used in furniture assembly, surface repair, etc.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol(PVA) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.

Modification of inorganic cementitious materials such as cement with polymer emulsion has been widely used. Since the water in the emulsion will immediately react with the cement after mixing the two and finally solidify, a two-component form is used in most cases. , measure and mix each component in proportion at the construction site. This brings inconvenience to the storage, transportation and construction of materials. The emergence of re-dispersible emulsion powder has changed the above phenomenon. Redispersible latex powder is a micron-sized thermoplastic resin powder obtained by spray-drying a polymer emulsion to remove water. It can be reduced to an emulsion after adding water.Due to this characteristic, it is widely used in single-component JS waterproof coatings, polystyrene board bonding mortars for building insulation, flexible surface protection mortars, polystyrene particle insulation coatings, ceramic tile adhesives, self-leveling mortars, dry-mix mortars, etc. It is widely used in fields that require modification of inorganic cementitious materials.   RDP is a polymer powder produced by spray drying of polymer emulsion. Polymer emulsions are mostly oil-in-water systems in which thermoplastic polymers with a solid content of about 50% are evenly distributed in water with fine particles (0.1-10 μm). After losing water, the polymer particles first form dense spheres and accumulate on the surface. Under the action of energy, discrete polymer particles form a continuous polymer body. To produce redispersible latex powder by the spray drying method, a layer of PVA protective film is added to the surface of the polymer in advance. Due to the existence of the protective film, the dry powders cannot merge. In order to prevent the rubber powder from agglomerating, some fine mineral powders are also added. , such as clay, etc. However, when redispersible latex powder is mixed with alkaline substances such as cement and water, the PVA will be saponified and adsorbed by the quartz in the sand and removed. The rubber powder that has lost its protective film can eventually form a continuous water-insoluble polymer. membrane.   The particle size of the rubber powder (5-250 μm) is much larger than the particle size of the polymer dispersed phase in the emulsion (0.1-10 μm), indicating that the latex particles will agglomerate during the spray drying process. In order to reduce the tendency of polymer powder to agglomerate during long-term storage, inert fluid materials such as clay, talc, silica and other fine particles are usually added to the dry powder as anti-stick fillers. The filler is determined according to the type of polymer and its glass transition temperature. The dosage is generally 8%-30% of the dry polymer powder, which is the main source of ash in redispersible latex powder. After redispersible latex powder is redispersed, the diameter of the latex particles becomes about (0.1-10μm).   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol(PVA) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.

VAE (ethylene-vinyl acetate copolymer) emulsion viscosity is an important quality indicator and has a significant impact on product mass transfer, heat transfer, fluid flow, emulsion stability and emulsion transportation. Monomer ratio, polymerization temperature, initiator, emulsifier system optimization, electrolyte additives, and storage conditions are all factors that affect the viscosity of VAE emulsion.   1. Monomer ratio The selection and proportion of monomers directly affect the viscosity and other properties of VAE emulsion. The ratio of ethylene to vinyl acetate (VAc) is particularly critical. Generally speaking, VAE emulsions with a VAc content of 70% to 95% have higher viscosity. Increased VAc content will increase the flexibility and elasticity of the emulsion, and will also increase the viscosity of the emulsion.   2.Polymerization temperature control Polymerization temperature is another important factor affecting the viscosity of VAE emulsion. Changes in temperature will affect the rate of free radical generation and the rate of polymerization. Generally speaking, within a suitable temperature range, an increase in temperature will speed up the polymerization reaction, causing the latex particles in the emulsion to grow rapidly, resulting in an increase in viscosity. However, too high a temperature may cause the emulsion to gel, affecting its quality and stability.   3.Initiator The amount and type of initiator have a significant impact on the viscosity of VAE emulsions. Initiators mainly affect the rate of polymerization. When the amount of initiator is large, the polymerization reaction is fast, the number of generated latex particles increases, and the viscosity of the emulsion increases. However, excessive initiator may cause the reaction to be too fast and difficult to control, resulting in reduced emulsion performance. Different types of initiators generate different types of free radicals during the reaction and have different effects on the viscosity of the emulsion.   4. Emulsifier system optimization The selection and dosage of emulsifier are crucial to the stability and viscosity of VAE emulsion. The main function of emulsifier is to reduce the surface tension of emulsion and promote monomer dispersion and emulsion formation. Appropriate emulsifier concentration and anionic/nonionic emulsifier ratio can improve the stability of the emulsion and also affect the viscosity of the emulsion. The degree of polymerization and alcoholysis of protective colloids such as PVA (polyvinyl alcohol) also significantly affect the viscosity of the emulsion. The higher the degree of polymerization of PVA, the greater the viscosity of the emulsion; the higher the degree of alcoholysis, the lower the viscosity of the emulsion.   5.Electrolyte additives The addition of electrolyte additives can affect the viscosity and stability of VAE emulsions. Some electrolyte additives can compress the electric double layer of latex particles and reduce the electrostatic repulsion between latex particles, thereby increasing the viscosity of the emulsion. However, excessive amounts of electrolyte additives may cause aggregation in the emulsion, affecting its performance.   The factors that affect the viscosity of VAE emulsions include reaction time and rate, PH value, storage conditions and stability. In actual production and application, these factors need to be reasonably adjusted according to specific needs and conditions to obtain VAE emulsion products with excellent performance.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol(PVA) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.