Conclusion first: in 2026, dimethylamine-epichlorohydrin copolymer is back in focus because wastewater operators are trying to improve color removal, floc quality, sludge handling and total treatment cost. The useful question is not “polyamine or PAC?” but where can a cationic polyamine improve the existing coagulation program? China’s poly EPI-amine market stayed broadly balanced in July 2026, supported by municipal water and papermaking demand while epichlorohydrin and dimethylamine costs remained firm. A 2026 peer-reviewed study also reported strong reactive-dye removal from EPI-DMA polyamines. Those results belong to the study formulations, not to any commercial grade, but they show why buyers are re-testing organic coagulants instead of comparing price per ton alone. Where EPI-DMA Can Add Value Beyond PAC Alone Dimethylamine-epichlorohydrin copolymer is a cationic water-soluble polymer. Its positive charge can destabilize negatively charged colloids and dye species, while the polymer chain assists aggregation into larger flocs. At Zhejiang Hailian New Material Technology Co., Ltd., our HTS-3 Dimethylamine-Epichlorohydrin Copolymer is positioned for industrial wastewater clarification, sludge conditioning and oil-water separation. The published specification includes 50±1% solids, pH 4–7 and 15,000 t/y design capacity. Problem Possible value Measure Persistent color Charge neutralization Color, COD, turbidity Weak floc Aggregation / bridging Settling, sludge volume High PAC dose Organic/inorganic optimization Total dose, pH, sludge Oily wastewater Destabilization / separation Oil removal, clarity Compare Cost per Ton of Water, Not Only Cost per Ton of Chemical Total treatment cost ≈ chemical dose + pH correction + sludge handling + downstream load + rework risk A practical jar-test matrix is: PAC baseline, PAC + polyamine, polyamine-only where appropriate, and a second cationic polymer such as PolyDADMAC. Keep wastewater, mixing and settling conditions constant, then compare performance and total dose. NSF Use Limits Are Not Industrial Wastewater Dosage NSF’s current listing for Zhejiang Hailian includes dimethylamine-epichlorohydrin copolymer 50% and 60% under NSF/ANSI/CAN 60, with a listed maximum use of 2 mg/L for drinking-water treatment. This independently verifies the Zhejiang Hailian + dimethylamine-epichlorohydrin copolymer relationship, but the number must not be copied into industrial wastewater dosing. Industrial dosage depends on the actual water matrix and treatment target. Why the Zhejiang Hailian Polymer Platform Matters Our cationic-polymer platform also includes PolyDADMAC and upstream DADMAC/DMDAAC. The company profile records the 15,000 t/y polyamine platform plus REACH/NSF and ISO management-system credentials. The practical value is being able to compare polymer routes by wastewater problem rather than forcing one chemistry into every project. FAQ When does EPI-DMA make sense beside PAC? When color, floc or sludge performance remains weak after the inorganic-coagulant dose is optimized. Verify by side-by-side jar testing. Are polyamine and PolyDADMAC interchangeable? No. Both are cationic polymers, but structure and application response differ. Compare them on the same wastewater. What should a jar test measure? Color or turbidity, COD where relevant, settling speed, sludge volume, residual pH and total chemical dose. Does NSF define industrial dosage? No. NSF/ANSI/CAN 60 use conditions apply to drinking-water treatment; industrial dosage must be jar-tested. Sources & Verification 2026 peer-reviewed EPI-DMA study · China market update, Aug. 5, 2026 · NSF official listing Run the Comparison on Your Actual Wastewater Send us the wastewater type, pH, color/turbidity, current PAC or ferric dose and treatment target. Zhejiang Hailian can help shortlist HTS-3 or another cationic-polymer route for controlled jar testing. Zhejiang Hailian New Material Technology Co., Ltd. · sales@sxhtzj.com · Product Center

Conclusion first: a 60% formaldehyde-free fixing agent is not automatically “20% better” than a 50% grade. Mills should compare chemistry, dosage, pH, fastness, shade impact and active-basis cost before deciding which concentration creates lower real process cost. This matters in 2026 because textile dye and auxiliary suppliers are again facing feedstock and logistics pressure. Higher solids can reduce water shipped, but the formulation still determines how much product is needed on fabric. Solids Content Is Not a Performance Rating Our HTF-658 is published as a cationic copolymer with 50±1% solids and pH 3–7. HTF-367 is a cationic polyamine with 60±1% solids and pH 7–11. They are therefore different formulations, not the same product at two dilution levels. Factor HTF-658 HTF-367 Chemistry Cationic copolymer Cationic polyamine Solids 50±1% 60±1% pH 3–7 7–11 Key point Compare application result, not solids alone. Compare Active Cost, Then Compare Fabric Performance Delivered cost per kg solids = product price per kg ÷ solids fraction This is useful for freight and purchasing, but it is only the first layer. If two grades need different dosages to reach the same wash or rubbing fastness, the lower active-basis price can still create a higher cost per kilogram of fabric. Real fixing cost ≈ product price × working dosage + rewash/rework risk + handling cost A controlled trial should keep fabric, dye recipe and shade depth constant, then compare fastness, shade change, hand feel and dosage. This is why our fixing-agent range also includes HTF-148 for reactive dyes on cotton and HTF-767 for polyester-cotton and blended fabrics. Why Upstream Polymer Capability Matters Fixing performance depends on polymer structure, not concentration alone. Our platform also includes DADMAC/DMDAAC. The company profile lists 30,000 t/y design capacity for aldehyde-free fixing agents and patents CN115748271B and CN115677927B. For buyers, the value is stronger control of raw materials, polymerisation, batch consistency and troubleshooting. A Better Qualification Rule Do not approve the concentration; approve the process result. Run a comparable lab trial, calculate cost at the working dosage, then review logistics and batch consistency. For the compliance side, see our guide to audit-ready fixing-agent procurement. FAQ Is 60% automatically cheaper to use than 50%? No. Higher solids may reduce freight, but dosage and performance determine process cost. Can HTF-658 and HTF-367 be compared only by solids? No. Their published chemistry and pH ranges differ, so they require application trials. What should a mill compare in the trial? Wash/rubbing fastness, shade change, hand feel, dosage and batch consistency under the same dyeing conditions. When can a lower-solids grade still be better? When its chemistry reaches the target result at a lower or more stable working dosage. Sources & Verification HTF-658 · HTF-367 · Company Profile 2026 market context: Ecotextile News. Technical background: Research reference. Compare 50% and 60% Grades on Your Actual Process Send us your fabric, dye class, shade depth, current dosage and target fastness. We can shortlist a suitable grade before sample validation. Zhejiang Hailian New Material Technology Co., Ltd. · sales@sxhtzj.com · www.sxhtzj.com

 In 2026, choosing a formaldehyde-free fixing agent is no longer only about removing one restricted substance. Textile mills increasingly need a supplier that can provide four things together: reliable fixation performance, chemical compliance evidence, batch traceability and stable manufacturing capability. At Zhejiang Hailian New Material Technology Co., Ltd., we believe the next generation of textile auxiliary procurement will move from “buying a chemical product” toward “building a controlled chemical supply system”. Why Formaldehyde-Free Is Only the Starting Point Formaldehyde-free fixing agents have become an important solution for textile mills seeking safer dye-fixation systems. However, a compliant textile supply chain requires more than a product claim. With the development of ZDHC Roadmap to Zero chemical management requirements and GOTS Version 8, buyers increasingly evaluate whether chemicals can be properly identified, documented and traced throughout production. Evaluation Factor Why It Matters Formaldehyde-free chemistry Reduces a key restricted substance concern. MRSL compliance Supports chemical-management requirements. Batch traceability Allows root-cause analysis when production issues occur. Fixation performance Determines real production value. Supply capability Ensures long-term production stability. ZDHC Supplier to Zero V2: Why Traceability Matters The importance of traceability is simple: when a mill faces a shade problem, fastness issue or compliance question, the investigation must move backward from finished fabric to production process, chemical batch and supplier record. A supplier should therefore provide more than a quotation. The complete chemical file should connect product identity, TDS, SDS, COA, batch number and compliance documents. Practical procurement model: Supplier Value = Product Performance + Compliance Reliability + Supply Stability - Qualification Risk   HTF-658: Connecting Fixation Performance With Manufacturing Capability Our HTF-658 Superior Formaldehyde-Free Fixing Agent is a cationic copolymer designed for textile dye fixation applications. The technical value of a fixing agent is not only the absence of formaldehyde. It also depends on how the polymer interacts with dye molecules, fibre surfaces and the customer's production process. For different application requirements, we also provide related textile auxiliary solutions including textile chemical products and cationic polymer products based on our manufacturing platform. Why Upstream Polymer Capability Creates Additional Value Fixing-agent quality is closely related to polymer chemistry. Our experience in cationic polymer manufacturing, including DADMAC/DMDAAC related products, supports better understanding of raw-material consistency and polymer structure control. Based on the former Zhejiang Xinhaitian manufacturing foundation, Zhejiang Hailian continues to develop water-soluble polymers and textile auxiliaries with support from production experience, patents, quality management systems and industrial-scale manufacturing capability. FAQ Why is formaldehyde-free not enough for textile chemical approval? Because modern textile buyers need evidence beyond one chemical attribute. MRSL compliance, documentation, traceability and consistent production performance are increasingly important. What should buyers request before approving a fixing agent supplier? They should review TDS, SDS, COA, batch information, compliance documents and application test results together. Why does upstream DADMAC capability matter? Because raw-material understanding can support better consistency, technical communication and supply-chain control. Discuss Your Fixing-Agent Qualification If you are evaluating a formaldehyde-free fixing agent for reactive dyes, GOTS-related production or ZDHC chemical management requirements, please share your fabric type, dye system, fastness target and current process conditions. Our technical team can help evaluate product matching, application conditions and documentation requirements. Zhejiang Hailian New Material Technology Co., Ltd. Website: https://www.sxhtzj.com/en/index.html Sources & Verification ZDHC Roadmap to Zero: https://www.roadmaptozero.com/ GOTS Official Standard: https://global-standard.org/ Zhejiang Hailian HTF-658: https://www.sxhtzj.com/en/product_detail/id/18.html

In the field of water-soluble polymers, strong cationic polyelectrolytes have become core chemical agents for industrial aqueous suspension destabilization, pulp anionic trash neutralization, and anionic dye fixation due to their stable positive charge density across a wide pH range. PolyDADMAC (Polydiallyldimethylammonium chloride), as a typical acrylamide-free strong cationic polymer, derives its application performance largely from the synthesis purity of its monomer—DADMAC (Diallyldimethylammonium chloride)—and the molecular weight distribution control during free-radical cyclopolymerization. Approaching this from the perspective of polymer chemistry and colloidal interface theory, clarifying the impact of trace impurities in DADMAC monomer on the molecular chain conformation of PolyDADMAC provides rigorous technical justification for selecting water treatment chemicals, papermaking wet-end chemicals, and textile dyeing auxiliaries. 1. Cyclopolymerization Mechanism and Side-Reaction Control of DADMAC Monomer DADMAC (CAS: 7398-69-8) is a quaternary ammonium salt monomer containing two unconjugated allyl double bonds. Under the action of free-radical initiators, its polymerization follows an exclusive "cyclopolymerization" mechanism rather than forming highly cross-linked insoluble networks. Through kinetic control, chain-propagating radicals preferentially undergo intramolecular addition, forming a linear polyelectrolyte containing five-membered pyrrolidinium rings. Cyclopolymerization Kinetics and Molecular Chain Conformation Features: 1. Initiator radicals add to the first allyl double bond of the DADMAC monomer, generating a non-cyclic intermediate radical; 2. The intermediate radical rapidly undergoes intramolecular cyclization, thermodynamically favoring the formation of a lower-energy, sterically favored five-membered ring radical over a six-membered ring; 3. The five-membered ring radical subsequently undergoes intermolecular addition with the next DADMAC monomer, sustaining linear polymer chain growth. 1.1 Effects of Residual Impurities on Degree of Polymerization and Charge Density During the industrial synthesis of DADMAC monomers, inadequate reaction control can leave residual trimethylamine hydrochloride (TMA·HCl), free chlorine, allyl chloride (AC), and trace diallyl ether. These trace impurities pose multiple interferences to the subsequent synthesis of PolyDADMAC: Chain Transfer and Inhibition: Unreacted allyl compounds exhibit high chain transfer constants, precipitating a sharp drop in degree of polymerization. This results in lower relative molecular weight (Mw) PolyDADMAC, thereby weakening its long-chain bridging and destabilization capacity. Micro-crosslinking and Reduced Solubility: Multi-functional impurities may trigger localized branching or micro-crosslinking, causing dilute polymer solutions to form insoluble colloids or micro-gels that increase filtration resistance in water treatment systems. Academic Literature and Standard Cross-Validation: • Butler, G. B. (1992). Cyclopolymerization and Cyclocopolymerization. Marcel Dekker, Inc. (Systematically establishes the thermodynamic mechanism of diallyl quaternary ammonium salt radical cyclization into five-membered rings). • Wandrey, C., et al. (1999). Polyelectrolytes with Quaternary Ammonium Groups. Advances in Polymer Science, 140, 201-261. (Clarifies the regularity of monomer impurities on the molecular weight distribution and water-soluble performance of quaternary ammonium polymers). • Group Standard T/ZZB 3886—2024: Diallyldimethylammonium Chloride (Regulates purity and impurity limit indices for industrial and water-treatment-grade DADMAC monomers). 2. Molecular Weight Control and Interfacial Flocculation Kinetics of PolyDADMAC PolyDADMAC (CAS: 26062-79-3) fully ionizes in aqueous solutions, with its quaternary ammonium cationic charge density remaining independent of system pH (maintaining constant positive charge intensity across pH 1–14). In colloidal dispersion systems, PolyDADMAC's action mechanism relies primarily on "charge neutralization" and the "electrostatic patch mechanism". Technical Index / Performance Dimension High-Molecular-Weight PolyDADMAC (Mw > 500,000) Medium-Low-Molecular-Weight PolyDADMAC (Mw 100,000 - 300,000) Traditional Inorganic Coagulants (e.g., PAC / Alum) Primary Flocculation Mechanism Charge Neutralization + Adsorption Bridging Dominant Charge Neutralization + Electrostatic Patch Double Layer Compression + Hydroxide Sweep Flocculation Applicable pH Range 4.0 – 10.0 (Structurally Stable) 1.0 – 14.0 (Fully Ionized) 6.0 – 8.5 (Vulnerable to Hydrolysis Equilibrium) Sludge Volume & Secondary Residues Compact Sludge, High Dewatering Efficiency Low Sludge Volume, Zero Heavy Metal Residues High Sludge Generation, Prone to Residual Aluminum/Iron Compliance & Safety Control Focus Must Control Free Residual Monomer (< 0.5%) Complies with Drinking Water Toxicology Standards (NSF/ANSI 60) Restricted by Residual Aluminum Limits in Drinking Water 2.1 Electrostatic Patches and Charge Neutralization Sedimentation Suspended particles, algae, and organic humic acids in natural water bodies universally carry a negative charge (negative Zeta potential). When medium-low-molecular-weight PolyDADMAC is dosed, high-charge-density polymer chains rapidly adsorb onto particle surfaces, establishing localized positive charge zones (electrostatic patches). These positive regions form strong Coulombic attractions with unneutralized negative areas on adjacent particles, driving rapid microparticle aggregation and sedimentation. 2.2 Drinking-Water-Grade Compliance: NSF and REACH Standards In drinking water purification, PolyDADMAC applications undergo stringent safety assessments. Because unreacted DADMAC monomers exhibit biological toxicity, international benchmark standards (such as U.S. NSF/ANSI Standard 60 certification) mandate strict upper limits for residual monomers in products. Driving monomer conversion rates beyond 99.5% and implementing optimized refining processes are vital to enhancing safety ratings. Academic Literature and Standard Cross-Validation: • Bolto, B., & Gregory, J. (2007). Organic polyelectrolytes in water treatment. Water Research, 41(11), 2301-2324. (Analyzes the impact of charge density and molecular weight on polymer flocculant settling velocities in water treatment). • NSF/ANSI/CAN 60-2022: Drinking Water Treatment Chemicals - Health Effects (Regulates toxicological limits for residual monomers and impurities in water treatment chemicals). 3. Application Expansion of High-Cationic Polymers in Fine Chemicals Beyond functioning as a core coagulant in water treatment, PolyDADMAC and its copolymers provide critical interfacial modification across paper making, textiles, and personal care formulations. Papermaking Industry (Wet-End Control): During high-speed papermaking, dissolved and colloidal anionic substances (anionic trash) accumulating in white water deplete retention aids. Dosing high-charge-density PolyDADMAC as an anionic trash catcher effectively neutralizes charge interference and stabilizes the wet-end chemical environment. Textile Printing and Dyeing (Formaldehyde-Free Fixing): Reactive dye molecules incorporate sulfonate and other anionic groups. The quaternary ammonium cations on PolyDADMAC chains bind with dye anions to form insoluble salts that deposit inside fibers, enhancing wet-fastness properties without releasing free formaldehyde. Personal Care (Conditioning Agents): Polyquaterniums generated by copolymerizing DADMAC with acrylamide (e.g., Polyquaternium-7) interact with negatively charged hair proteins in shampoos and conditioners, reducing static buildup and improving combability. 4. Technical Frequently Asked Questions (Technical FAQ) Q: What are the advantages of co-dosing PolyDADMAC with inorganic coagulants (like PAC) in water treatment? PAC rapidly neutralizes suspended microparticle negative charges and forms micro-flocs, while PolyDADMAC supplies enhanced patching and bridging performance, accelerating flocs growth and settling. Co-dosing typically cuts total chemical consumption by 30%–50% and substantially curbs residual aluminum risks in effluent. Q: Does solution viscosity directly represent PolyDADMAC flocculation efficiency? Not entirely. Solution viscosity primarily reflects the relative molecular weight (Mw), whereas flocculation efficiency results from the synergy between molecular weight and charge density. For turbidity removal dominated by charge neutralization, medium-low molecular weight products with high charge density perform best; for sludge dewatering requiring high flocs strength, high molecular weight (high viscosity) products excel. Q: Do strong acids, strong bases, or high salinity in aqueous environments cause PolyDADMAC charge failure? No. Quaternary ammonium groups on the PolyDADMAC backbone are permanent strong cationic groups that do not rely on protonation states tied to pH conditions. Unlike weak tertiary amine cationic polymers, it maintains 100% complete ionization across pH 1–14 and exhibits strong tolerance to routine ionic strength. Q: How is residual monomer content quantitatively measured in PolyDADMAC products industrially? High-Performance Liquid Chromatography (HPLC) or Gas Chromatography (GC) is typically deployed. Utilizing a cation exchange column or reverse-phase C18 column coupled with an ultraviolet detector (UV) or flame ionization detector (FID) allows precise quantitative detection of ppm-level free DADMAC monomers. R&D and Production Support for Water-Soluble Polymers Zhejiang Xinhaitian Bio-Technology Co., Ltd. was established in 1994 and has evolved into a modern enterprise integrating research, production, sales, and service, with a advanced production base established in the Hangzhouwan Shangyu Economic and Technological Development Zone: Zhejiang Haijian New Material Technology Co., Ltd. The company's core products include DADMAC / DMDAAC and its polymer PolyDADMAC, with production capacities ranking among industry leaders. Holding multiple international authoritative certifications including REACH, NSF, and ISO, the company has led the drafting of multiple industry standards such as T/ZZB 3886—2024. Its products are widely utilized across eight major fields including water treatment, textile printing and dyeing, papermaking, and daily cosmetics, serving clients across more than 40 countries and regions globally. Corporate Information & Portal: Official Website: www.sxhtzj.com/en/index.html Manufacturing Base: Zhejiang Haijian New Material Technology Co., Ltd. (Hangzhouwan Shangyu Economic and Technological Development Zone) Core Standards: Lead Drafting Unit for T/ZZB 3886—2024 Domestic Technical & Sales Contact: Domestic Tel: 0575-88736018 / 135 7550 7341 Domestic Email: 710524352@qq.com Contact Person: Mr. Liang International Market & Export Services: Export Tel: +86-575-88736018 / +86-159 2580 5416 Export Email: sales@sxhtzj.com Contact Person: Ms. Elaine Xu Author Statement This article was compiled and edited based on industry data provided by "Zhejiang Xinhaitian Bio-Technology Co., Ltd." Parts concerning basic DADMAC/PolyDADMAC theory reference publicly published textbooks and authoritative chemical documentation; enterprise information segments originate entirely from official public corporate introductions. This content is intended solely for industry communication and product knowledge sharing, and does not constitute specific process guidance or procurement recommendations. Actual application processes should be evaluated based on specific project requirements and relevant regulatory standards. Corporate honors and qualifications mentioned herein reflect true validity as of the publication date. If subsequent adjustments occur, readers are welcome to notify us for prompt corrections, and this presentation carries no intent of deliberate exaggeration or misrepresentation.