Superabsorbent Polymers Superabsorbent Polymers (SAP)

Basic Information

Superabsorbent polymers (SAP) can absorb several hundred to several thousand times their own weight in water.
SAP have a wide range of uses including not only everyday items such as disposable diapers, pet sheets, air fresheners, and disposable hand and body warmers, but also in fields such as medicine and health care, greenery, and civil engineering.
Compared to similar water-absorbing materials of pulp and sponges, SAP are highly absorbent and do not easily lose liquid (syneresis) even when pressure is applied.

Details of Functions

Water Absorption Principle

When SAP come into contact with water, the difference in ionic concentration between the inside of the SAP and water generates osmotic pressure; SAP uses this difference in osmotic pressure to absorb water.
The affinity between SAP and water also facilitates the absorption of water; however, this affinity does not significantly affect the water-absorbing ability of SAP to the extent that osmotic pressure does.
This water-absorbing ability can also be controlled by the crosslinked structure of SAP.
This water absorption principle is the same principle when the liquid being absorbed is an aqueous solution.

Illustration of Water Absorption Principle

Features and Properties

Global Top Share

Nippon Shokubai’s SAP boasts a top level of share in global markets.
About one quarter of the disposable diapers manufactured in the world use SAP produced by Nippon Shokubai.

Graph of SAP Production capacity

Global Production System

Nippon Shokubai produces SAP at five bases around the world.
(Japan, China, Indonesia, USA, and Belgium)

Illustration of Global Production System

Integrated Production Starting with the Raw Material of Acrylic Acid

Nippon Shokubai produces SAP in an integrated system, starting with the raw material of acrylic acid.

Illustration of Integrated Production Starting

Development of Sustainable SAP

Nippon Shokubai is developing sustainable SAP that contributes to lessening the environmental load.

Biomass Certification

The SAP produced at the Belgium subsidiary NIPPON SHOKUBAI EUROPE N.V. has acquired Biomass Certification from the International Sustainability & Carbon Certification (ISCC) Association.

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Development of New Recycling Technologies for SAP

Nippon Shokubai has jointly developed new technologies for recycling superabsorbent polymers (SAP) in used disposable diapers.

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Illustration of Development of New Recycling Technologies for SAP

Extensive Lineup

Nippon Shokubai has a lineup of several SAP products, which are roughly sorted into the three types listed below.
We are able to suggest the appropriate SAP type and product to suit your requirements. Please freely inquire with us for details.

FeaturesGeneral-purpose type
(Daily-use items)
Salt-tolerant type
(Civil engineering)
For water retaining agents
AppearanceWhite powderWhite powderWhite powder
Absorption Amount
Deionized Water300-1,000100-200200-300
Normal Saline Solution (NSS)*130-6030-40
Artificial Seawater*210-2020-30
Calcium Chloride Aqueous Solution*31-510-15
Average Particle Diameter (μm)300-45010-100800-1,000
Examples of ApplicationsDisposable diapers, Feminine hygiene products, Pet sheets, Refrigerants, Disposable hand and body warmers, Waste liquid solidifiers, Air fresheners, Drip sheetsWater blocking agents for civil engineering,Water blocking agents for cablesWater retaining agents for horticulture, growing grass, and planting trees and shrubs for greenery
*1:0.9% sodium chloride aqueous solution
*2:Aqueous solution of 43.0 – 48.0 mS/cm electrical conductivity containing univalent – bivalent ions
*3:5% calcium chloride aqueous solution