Superabsorbent Polymer

About Superabsorbent Polymer

Superabsorbent Polymer (SAP) is a material capable of absorbing several hundred to 1,000 times its own weight in water. Even when subject to pressure, this polymer securely retains the absorbed liquids. In 1978, we were the first in the world to begin commercial production of SAP. Today, SAP is used in a wide range of applications, from hygiene materials used mainly in disposable diapers and sanitary products to non-hygienic applications such as agriculture & horticulture, pet, construction and civil engineering, etc.

Mechanism of absorption

SAP are crosslinked networks of flexible polymer chains. The polymer chains are shrunk before absorbing water. When water comes into contact polymer chains, these chains are expanded. Water is trapped tightly within networks.

Applications of SANFRESH SAP

“SANFRESH” is a superabsorbent polymer (SAP) that can help control water in various situations and contribute to SDGs Goal 6 “Ensure access to water and sanitation for all” as a representative for portable toilet applications.

Note: The information contained herein does not constitute an endorsement of any patent or guarantee of its use.


Soil water retention agent

Typical products in the agricultural and horticultural fields are soil water retention agents.

Other applications include sheets for seedling growth, fertilizers, and slow-release fertilizers that coat the surface of fertilizers and pesticides to improve their slow release in the soil.

Seedling sheet

Seed coating

Medical and Cosmetics

Waste blood treatment

Super absorbent polymers are used to solidify (gel) blood waste generated during surgical procedures at medical sites. Waste blood is collected in special containers and solidified with superabsorbent polymers to prevent the risk of secondary infection due to leakage of waste blood during storage, transportation, and treatment processes.

Among our products, “SANFRESH ST-250*” is suitable for this application because of its rapid gelation and resistance to leakage.

Medical dressing


Safety and environmental protection

Flood prevention system

Super absorbent polymers are used in “water-absorbent sandbags“, which are widely used as disaster prevention equipment for flooding that occurs during hurricanes and torrential rains. Ordinary sandbags are made by filling a bag with soil, but “water-absorbent sandbags” are completed by soaking a bag containing super absorbent polymers in water. In addition to being quick to prepare, they are lightweight and take up little space for storage.

“SANFRESH ST-500D*“, which forms a hard gel, is effective for use.

Slope planting

Fire Extinguishing materials

Construction and Mining

Improvement of slurry handling

Super absorbent polymers are used to improve handling of slurries with high water content. After adding a small amount of SAP, the slurry becomes less fluid and easier to transport.

Concrete modifier

Absorbent for mining industry

Machineries and Energy

Gelling Agent for alkaline batteries

Cables and wires


Rubber manufacturing

Ice pack/Gel pack


SDP Global, a subsidiary of Sanyo Chemical, is the world leading manufacturer specialized in SAP, and SANFRESH is Sanyo’s brand with more than 40 years experience.

SANFRESH is supported by three core technologies

We work on improvement of core technologies and application development.

Typical properties of SANFRESH SAP

Product NameFeaturesAppearanceAbosrbency (Ion-Exchange Water) g/gMean Particle Diameter µm
SANFRESH ST-250*High absorbencyWhite powder600380
SANFRESH ST-500D*Relatively high gel strengthWhite powder400380
SANFRESH ST-500MPSAHigh thickening properties
Fine particles
White powder60030

Precaution Against Mishandling

  • SAP powder’s aggregation caused by moisture in air or water contamination may cause some troubles (Ex. blockage in machine’s pipelines, overload to a motor etc.). Please avoid moisture and water contamination.
  • A water-absorbed SAP tends to be separated to gel and water at high temperature. We recommend to use SANFRESH products under 50℃.
  • Water-absorbed SAP is susceptible to exposure from ultraviolet rays (UV). Excessive UV exposure may cause water-absorbed SAP to release water. When it is used under direct sunlight (Ex. outdoors), the use of non-transparent package or packaging with UV-blocking properties is recommended.