Alcotex 55-002H

Polyvinyl chloride (PVC) is one of the most widely used plastics, and its properties largely depend on the morphology, porosity, and bulk density of the PVC particles formed during suspension polymerization. The role of the suspending agent is crucial in the suspension polymerization process. ALCOTEX series polyvinyl alcohol products are specifically developed as secondary suspending agents (or pore enhancers) to synergize with conventional primary suspending agents, jointly optimizing the microstructure and macroscopic properties of PVC resin. 1. What is an auxiliary dispersant? In complex dispersion systems, a single primary dispersant often struggles to simultaneously address multiple requirements such as wetting, depolymerization, and stabilization. This is where the role of auxiliary dispersants becomes prominent. They significantly improve the dispersion stability and flowability of the entire system by adjusting the surface tension of the system, improving the charge distribution between particles, and enhancing the adsorption capacity of the primary dispersant. In pigment systems, it reduces the risk of flocculation and sedimentation; In emulsion polymerization, it controls particle size distribution and polymerization rate; In rubber latexes, it prevents particle agglomeration and improves emulsion storage stability.   2. Comparison of Technical Characteristics of ALCOTEX Series Products Property Appearance Total Solids (%) Degree of Hydrolysis (mole %) Viscosity@23℃ (mPa.s) ALCOTEX 45 Colourless to pale straw/clear to slight haze 34.0 - 36.0 43.0 - 47.0 300 - 600 ALCOTEX 552P Slightly Yellow aqueous solution 39.5 - 40.5 54.0 - 57.0 800 - 1400 ALCOTEX 432P Water white to pale straw/clear to slight haze 39.0 - 41.0 43.0 - 46.0 100 - 180 ALCOTEX 552P Slightly Yellow aqueous solution 39.5 - 40.5 54.0 - 57.0 800 - 1400 ALCOTEX 55-002H Very pale yellow solution 38.5 - 39.5 54.0 - 57.0 1000 - 1500   High Hydrolysis Degree Products (approximately 55% mole %): 55-002H and 552P ALCOTEX 55-002H: A colloidal dispersion of polyvinyl alcohol (PVA) with a high degree of hydrolysis (54.0-57.0 mole %). Nuclear magnetic resonance (NMR) measurements show a random distribution of its acetate groups. For application, it is recommended to add a portion of the primary suspending agent before adding 55-002H to ensure good dispersion of the secondary additive. It is strictly forbidden to add it to the VCM feed line. ALCOTEX 552P: A 55% aqueous solution of hydrolyzed PVA, also with a high degree of hydrolysis. It has a low residual methanol content (<2% w/w) and a high cloud point (>45℃). It can be directly added to the reactor or pumped into a flowing water feed line. It is recommended to add 552P after adding at least a portion of the primary suspending agent.   Low degree of hydrolysis products (approximately 43%-45% mole %): WD100, 432P, and 45 ALCOTEX WD100: A 43% aqueous solution of hydrolyzed polyvinyl alcohol, characterized by extremely low methanol content (<2% w/w). It can be infinitely diluted with water. Compared to conventional products, WD100 provides higher porosity for PVC resin and reduces gel or "fisheye" formation. Unlike traditional secondary additives, WD100 can be added before the primary suspending agent, or as a stable primary/secondary suspending agent co-solution. Adding via the water feed line is recommended. ALCOTEX 432P: A low-viscosity methanol-based solution of 43% hydrolyzed polyvinyl alcohol, with the lowest viscosity in the series (100-180 mPa·s). Due to its methanol solubility, its storage and transportation must strictly comply with local regulations regarding flammability and toxicity. It is typically pumped directly into the reactor after the addition of water and the primary stabilizer. ALCOTEX 45: A 45% hydrolyzed polyvinyl alcohol (PVC) water/isopropanol solution with moderate viscosity (300-600 mPa·s). Due to the presence of isopropanol, it is also subject to local flammability regulations. Its nuclear magnetic resonance (NMR) results also show a random distribution of acetate groups. It is typically pumped into the reactor after the addition of water and the main suspending agent. All ALCOTEX products are designed to optimize the porosity/bulk density relationship, resulting in the following practical production advantages: Highly efficient VCM removal: Increased porosity allows for more thorough VCM release, permitting the use of gentler stripping conditions, potentially reducing stripping time, steam consumption, and stripping temperature. Optimized plasticizer absorption: Improves PVC's ability to absorb plasticizers, particularly beneficial for manufacturing flexible PVC products. Product consistency and design: ALCOTEX helps achieve a more uniform pore distribution and tends to make PVC particles more spherical, thus improving bulk density. This provides flexibility in polymer design, such as achieving higher conversion rates at a given porosity.   3. Conclusion  The ALCOTEX series of secondary suspending agents are powerful tools for S-PVC manufacturers to optimize product structure and improve production efficiency. By precisely controlling the degree of hydrolysis, solution form, and addition method of polyvinyl alcohol, these products can significantly improve the porosity/bulk density relationship of PVC, simplify the stripping process, and ultimately enhance the thermal stability and processing performance of the product. Manufacturers can select the most suitable secondary suspending agent from this series based on their own equipment conditions, the required PVC molecular weight range, and sensitivity to methanol/isopropanol content.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com  

One of the core challenges in the suspension polymerization process of polyvinyl chloride (PVC) is polymer scaling on the inner walls and internal components of the reactor. Scale buildup has a negative impact on reactor heat transfer and extends the time it takes for polymerization. More importantly, companies have to do expensive, high-pressure cleaning on their reactors on a regular basis, which reduces how much the equipment can be used. ALCOTEX 225 and ALCOTEX 234 scale inhibitors offer a way to address this issue.     1.Industrial Impacts and Scaling Inhibition Needs of Scaling  Scaling happens in polymerization when free radicals or monomers in water stick to solid surfaces like reactor walls or agitators. They then deposit and polymerize more on these surfaces. These solids, especially metals, can have higher temperatures or provide good places for polymerization, which causes local hot spots or uneven reactions. Scaling has several negative effects on S-PVC production, including:  Limited Production Cycle: A certain number of runs must be completed before shutdown for cleaning, limiting continuous production capacity. Product quality fluctuations: Detached scale contaminating the resin can lead to deterioration in product color, thermal stability, and impurity content. Energy consumption and maintenance costs: Increased energy consumption due to the investment in high-pressure cleaning equipment and labor, as well as decreased heat transfer efficiency. The S-PVC industry focuses on making good scale inhibitors because it helps reactors run longer without stopping.   2. ALCOTEX 225: The Main Barrier Against Reactor Wall Sticking ALCOTEX 225 is clearly defined as a scale inhibitor for vinyl chloride suspension polymerization. Its design goal is to eliminate polymer scale buildup on the inner wall of the reactor. 2.1. Physicochemical Properties Property Typical Value Appearance Dark blue aqueous solution Total Solids 5.0–6.0 PH 12.5–13.0 2.2. Mechanism of Action ALCOTEX 225 (POVAL L-10) achieves anti-sticking by forming an extremely thin protective layer on the inner wall of the reactor. This protective layer primarily functions to: Passivate active sites: Cover and passivate active sites on the metal surface that may initiate free radical polymerization. Change surface energy: Adjust the surface energy of the reactor wall to make it unfavorable for the adsorption and wetting of polymers and monomers. Physical Barrier: Establishes a physical barrier to effectively prevent the adhesion and deposition of VCM monomers or primary polymer particles on the reactor wall. This treatment method ensures the reactor wall remains clean during polymerization, which is key to achieving a significant increase in the number of production runs before cleaning.   3. ALCOTEX 234: Synergistic Protector for Internal Components ALCOTEX 234 is not used alone but is designed to work in conjunction with ALCOTEX 225 as a scaling inhibitor. It focuses on areas that are difficult for ALCOTEX 225 to completely cover or are susceptible to mechanical wear. 3.1. Physicochemical Properties Property Typical Value Appearance Dark blue aqueous solution Freezing Point - 1 Specific Gravity 1.1 Total Solids 19.0-21.0 Viscosity @20℃ < 20 PH > 13.0 3.2. Synergistic Application and Targeted Scaling The main function of ALCOTEX 234 is to eliminate scaling on baffles, agitators, or other areas with poor surface quality inside the reactor. Key Protection Areas: Baffles and agitators are areas subjected to high shear forces during polymerization and are also the areas with the most intense heat transfer and monomer/polymer contact. Scaling in these areas is often more stubborn and difficult to inhibit. Synergistic Effect: By applying ALCOTEX 225 to the reactor walls and ALCOTEX 234 to internal components such as agitators and baffles, a comprehensive, high-strength protection is achieved over the entire polymerization contact surface. This combined application strategy is essential for improving overall production efficiency.   4. Application Implementation and Maximizing Industrial Benefits The use of ALCOTEX 225 and 234 imposes specific requirements on the operation of the polymerization process to ensure maximum effectiveness: Thorough Pretreatment: Before first use of the system, all previous polymerization residues in the reactor must be thoroughly removed, and the reactor must be cleaned and dried. Any residual polymer or impurities will affect the adsorption and film formation of the inhibitor. Formulation and Measurement: The concentration and coating amount of the inhibitor need to be precisely optimized based on the reactor geometry, material, and polymerization formulation of the target PVC product. Industrial Benefits: Successful application of the inhibitor system directly results in higher production runs, significantly increased productivity, and improved stability of PVC resin quality.   The ALCOTEX 225 and 234 system is not merely a cleaning agent, but a specialized surface modification and protection system. Together, they constitute a mature and efficient S-PVC scaling management solution, which is a key technological support for modern PVC polymerization plants to achieve high-yield, stable, and high-quality production.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

In the polyvinyl chloride (PVC) suspension polymerization process, selecting the right suspending agent is crucial for controlling polymer particle morphology, particle size distribution, and porosity. Both ALCOTEX B72 and its modified version, ALCOTEX B72-LF, are high-performance polyvinyl alcohol (PVA) specifically developed as primary suspending agents for VCL suspension polymerization. B72 and B72-LF share similar applications and properties, but B72-LF is designed to solve a frequent problem in polymerization. Here, we will compare the technical specs, benefits, and proper uses of both B72 and B72-LF. This information should guide PVC manufacturers to select the right product for their specific needs.      1. Comparison of Core Technical Parameters Property ALCOTEX B72  ALCOTEX B72-LF Appearance Dark yellow granulesanules Dark yellow granulesanules Degree of Hydrolysis 72.0-74.0 72.0-74.0 Viscosity @ 20℃, 4% solution 5.0-5.8 5.0-5.8 Ash Content 0.5 max 0.5 max Total Solids > 95.0 > 95.0   2. Differentiation of Application Advantages—Process Optimization vs. Product Quality The advantages of ALCOTEX B72 primarily focus on reducing operating costs and improving PVC polymer quality. The ALCOTEX B72-LF builds upon this foundation with enhanced process stability.   2.1 Shared Quality Advantages of the B72/B72-LF Reactor Output and Cost: Low fouling in polymerization reactors reduces downtime for cleaning. Required particle size control can be achieved at lower concentrations. Particle Morphology and Flowability: The resulting PVC particles tend to be more spherical, helping to minimize bulk density reduction at high porosity, resulting in optimal flow properties. Porosity and Degassing: The produced PVC particles exhibit good porosity, facilitating the removal of free monomers. Defect Control: Narrow particle size distribution and low oversized reject rate. Low "fisheye" count reduces reject levels in critical applications. Plasticizer Absorption: Adjustable plasticizer absorption properties provide fast drying times. Operational Characteristics: Low dust generation.   2.2 B72-LF's Unique Advantage: Anti-Foaming Properties Foaming is a common process obstacle in suspension polymerization, potentially leading to reduced reactor charge, increased reactor wall fouling, and even impacting polymerization stability. ALCOTEX B72-LF was specifically developed to address this foaming issue. It offers the added benefit of reducing foaming during S-PVC polymerization. Process Benefits: By minimizing foaming during suspension polymerization, B72-LF can help manufacturers maintain or improve throughput and production efficiency. Comparative Conclusion: B72 focuses on providing comprehensive, high-quality PVC product specifications and excellent operating characteristics. B72-LF builds on this strength, offering manufacturers struggling with foaming a process solution without compromising PVC quality.   3. Similarities in Storage and Logistics Both products demonstrate high consistency in storage and supply, facilitating standardized supply chain management and operational procedures: Storage Conditions: Both products should be stored in a dry area, and moisture ingress must be avoided to maintain product quality. Shelf Life: As supplied, both products should maintain suitability for 24 months from the date of production. Testing Recommendations: Both products recommend testing before use for materials stored for 12 months or longer. Aqueous Solutions: Aqueous solutions of both products are susceptible to mold and bacterial attack if stored at elevated temperatures for extended periods. Packaging: Both products are supplied in 25 kg plastic bags and 1000 kg bulk bags.   4. Application Selection Recommendations ALCOTEX B72: Standard Process: Stable process operation with minimal foaming issues. The primary goal is to achieve high-quality PVC pellets and low operating costs. Cost-Effectiveness and Quality Assurance: Achieve excellent particle size, porosity, flowability, and low defectivity with minimal investment. ALCOTEX B72-LF Challenging Process: Significant foaming tendency during polymerization, or manufacturers seeking to maximize reactor load and throughput. Process Optimization and Efficiency Improvement: Maintains all the quality advantages of B72 while providing strong anti-foaming properties, ensuring stable and efficient production processes.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com