Sodium Polyacrylate
Thickeners
9003-04-7
(C₃H₃NaO₂)ₙ
$2.38 ~ $3.57
Food
Free sample from 100g(NF)
One unit of:25kg/bag
One unit of:25kg/bag
25kg/bag
Product Info
What is Sodium Polyacrylate?
Sodium Polyacrylate is a synthetic superabsorbent polymer used in the food industry as a safe thickening agent, stabilizer, and emulsifier to improve texture, prevent separation, and extend product shelf life.
How is Sodium Polyacrylate made?
| Step No. | Production Stage | Key Action | Control Point & Note |
|---|---|---|---|
| 1 | Monomer Neutralization | Reacting acrylic acid monomer with a sodium base (e.g., sodium hydroxide) in water to form a sodium acrylate solution. | The degree of neutralization (typically 65-75%) and reaction temperature must be strictly controlled. This step is highly exothermic and sets the initial pH and monomer concentration. |
| 2 | Polymerization | Adding an initiator and cross-linking agent to the monomer solution and initiating the polymerization reaction, transforming the liquid into a solid, rubbery hydrogel. | Control of initiator dosage and the temperature profile is critical for achieving the desired molecular weight and gel strength. The reaction must proceed to near-full completion. |
| 3 | Gel Crushing & Granulation | Mechanically chopping or extruding the large slab of hydrogel into smaller, more manageable particles. | The particle size of the wet gel must be relatively uniform to ensure consistent and efficient drying in the next stage. |
| 4 | Drying | Removing water from the hydrogel particles in a continuous belt or fluid bed dryer until a specific low moisture content is achieved. | Drying temperature and duration are key. Over-drying can degrade the polymer, while under-drying leaves excess moisture. The target residual moisture content is a critical quality parameter. |
| 5 | Milling & Sieving | Grinding the dried polymer into a powder and then classifying it through a series of screens to achieve the target particle size distribution. | The final Particle Size Distribution (PSD) is crucial for the product's application performance, affecting absorption rate and permeability. Fines are often recycled. |
| 6 | Surface Cross-linking | Treating the surface of the polymer particles with another cross-linking agent and applying heat to cure it. | This optional but vital step significantly enhances Absorbency Under Load (AUL). The amount of agent and curing temperature/time must be precise to avoid particle agglomeration or damage. |
| 7 | Final Screening & Packaging | Conducting a final quality screening to remove any oversized particles or agglomerates before packaging the finished product. | Final QC checks ensure product specifications are met. Packaging must be moisture-proof to maintain the polymer's superabsorbent properties until use. |
Technical Specifications
| CAS Number | 9003-04-7 |
| Chemical Formula | (C₃H₃NaO₂)ₙ |
| Solubility | Soluble in water; insoluble in ethanol, ether; absorbs 100–1000× weight water |
| Storage Conditions | Store sealed in cool, dry place (2–25 °C) |
| Shelf Life | 36 Months |
Applications & Usage
Common Applications:
Food packaging moisture absorber
thickener in sauces/dairy
medical dressings
diapers
Mechanism of action:
| Parameter | Sodium Polyacrylate |
|---|---|
| Functional Category | Thickener; Stabilizer; Humectant; Superabsorbent Polymer (SAP). |
| Key Ingredients | Polymer of acrylic acid, neutralized with sodium hydroxide. |
| Mechanism of Action | Forms a high-viscosity hydrogel by absorbing and retaining large volumes of water via osmosis. The carboxylate groups on the polymer backbone ionize, creating electrostatic repulsion that uncoils and expands the polymer network, trapping water molecules. Acts as a humectant by binding water and preventing its evaporation. |
| Application Effect in Product | Significantly increases viscosity and provides a smooth, thickened texture in dressings and sauces. Prevents ice crystal formation in frozen foods. Maintains moisture and improves mouthfeel in baked goods and processed meats. Reduces syneresis and stabilizes emulsions. |
Comparison:
| Product Name | Category/Type | Key Features | Strengths (vs peers) | Weaknesses (vs peers) | Best Use Cases | Why Choose |
|---|---|---|---|---|---|---|
| Sodium Polyacrylate | Superabsorbent Polymer (SAP) | Absorbs up to 800x its weight in distilled water; forms a stable hydrogel; high absorption speed. | Highest absorption capacity and retention under low load; cost-effective for mass production. | Petroleum-based (poor biodegradability); absorption capacity is significantly reduced by salts (e.g., in urine). | Disposable diapers, sanitary napkins, adult incontinence products, artificial snow, absorbent pads. | For maximum liquid absorption and retention at the lowest cost in disposable hygiene products. |
| Potassium Polyacrylate | Superabsorbent Polymer (SAP) | High water retention in soil; slowly releases water to plants; long-lasting in soil environments. | Optimized for agriculture; breaks down to provide potassium fertilizer; better performance in saline soil conditions. | Lower absorption speed and overall capacity than sodium-based SAPs; higher cost for general use. | Agriculture, horticulture, forestry, and landscaping for water conservation and drought management. | When the primary goal is slow-release water retention for plants and soil conditioning. |
| Polyacrylamide | Synthetic Polymer / Flocculant | Water-soluble; acts as a soil conditioner to prevent erosion; effective flocculating agent. | Excellent at binding soil particles to reduce erosion; very effective in water clarification. | Much lower bulk liquid absorption than SAPs; potential toxicity concerns from unpolymerized acrylamide monomer. | Erosion control (hydroseeding), wastewater treatment, oil recovery, laboratory gel electrophoresis. | For applications requiring soil stabilization or water clarification, not bulk liquid absorption. |
| Sodium Carboxymethyl Cellulose (CMC) | Modified Natural Polymer / Thickener | Derived from renewable cellulose; biodegradable; acts as a thickener, binder, and stabilizer. | Renewable and biodegradable; multifunctional as a thickener and binder in addition to absorbing water. | Significantly lower absorption capacity and retention under pressure compared to SAPs. | Food thickener, pharmaceutical binder, component in drilling fluids, paper manufacturing, some absorbent products. | For a biodegradable option where thickening or binding is needed alongside moderate absorption. |
| Cellulose Fluff Pulp | Natural Absorbent Fiber | Derived from wood; high wicking rate for liquid distribution; provides structural integrity and softness. | Renewable and biodegradable; excellent for rapid liquid acquisition and distribution; provides product bulk. | Very low absorption capacity per gram; poor liquid retention under pressure (leaks easily). | Core matrix of diapers and pads (used with SAP), absorbent wipes, air-laid nonwovens. | For fast liquid wicking and distribution, providing structure, or when a fully natural material is required. |
| Starch-Graft Polyacrylate | Bio-based Superabsorbent Polymer | Partially derived from starch (a renewable resource); designed for enhanced biodegradability. | Improved environmental profile and biodegradability compared to purely synthetic SAPs. | Generally has lower absorption capacity and retention under load; typically higher cost. | Environmentally-marketed disposable hygiene products, agricultural applications where biodegradability is key. | For a balance between superabsorbent performance and a reduced environmental footprint. |
Technical Documents
Available Documentation
COA, Technical Spec, MSDS
Safety Data Sheet (SDS)
Provided
Certificate of Analysis (COA)
Quality assurance documentation
Technical Data Sheet
Detailed technical specifications