Learn More About Diaper Super Absorbent Polymer

1.Diaper super absorbent polymer

Diaper super absorbent polymer (or SAP) is a synthetic polymer primarily used as a water-absorbent material due to its unique property of absorbing large amounts of water relative to its mass. The use of diaper super absorbent polymer is an innovation, especially since it was applied to diapers decades ago. It is now widely used in baby diapers, incontinence products and sanitary napkins.

Most of the diaper super absorbent polymers currently on the market are produced by free radical polymerization of acrylic monomers under the action of crosslinking agents. During use, the special three-dimensional structure formed inside makes it exhibit the unique property of absorbing a large amount of water.

The absorbent core of diapers is composed of fluff pulp and diaper super absorbent polymer to absorb urine. The current research direction is to reduce the amount of fluff pulp to make the diapers smaller and thinner, while maintaining the same overall absorbency. Therefore, after reducing the amount of fluff pulp, more SAP power is required in diapers to maintain the total absorbency. And improve it to meet the product quality requirements, such as improving its liquid permeability, to make up for the loss of core bulkiness and liquid transmission function caused by the reduction of the amount of fluff pulp. After its fluid permeability is improved, the absorption properties such as centrifugal water retention capacity (CRC) need to be maintained at an acceptable level, and the absorption capacity under pressure (AUP) should be maintained at a high level.

2.Liquid permeability of diaper super absorbent polymer

Liquid permeability refers to the ability of a porous material to allow liquids to pass through. For diaper super absorbent polymer, liquid permeability is very important in sanitary products, mainly refers to the permeability of liquid in the swollen state of SAP particles in the core layer, so it is also called gel layer permeability (GelBedPermeability, GBP) . Low fluid permeability or low GBP values indicate a low flow rate of liquid through the swollen SAP gel layer.

In the actual application of diapers, lower GBP will cause the urine to diffuse poorly in the core, which will lead to product performance problems in diapers. During the use of diapers, urine must diffuse and penetrate into the core, otherwise gel blocking will occur. This phenomenon occurs when the second urine is blocked by the swollen super absorbent polymer and cannot penetrate downwards, but flows to Otherwise, leakage will occur. In order to make the gel layer have better liquid permeability, open channels should be formed between the swollen SAP particles to allow liquid to pass through. To achieve this, SAP particles must maintain sufficient stability in the swollen state, that is, individual particles should have sufficient gel strength under pressure. If the gel particles do not have sufficient strength, not only will no pores between the particles be created under pressure, but a barrier will be formed to prevent the passage of liquid.