The secret of the absorbent core of baby diapers: How does the multi-layer structure design ensure lasting dryness?

The absorbent core of absorbent baby diapers is the core of the diaper's absorbent performance, and its design directly determines the diaper's water absorption speed, water absorption capacity, and water locking ability. Generally speaking, the absorbent core adopts a multi-layer structure design, and each layer has different functions and works together to achieve excellent water absorption performance.

The surface layer of the absorbent core is usually made of super absorbent resin (SAP) or special fiber materials, which have extremely high water absorption speed and water absorption capacity. When urine contacts the surface of the diaper, these materials can respond quickly and absorb urine into the interior to form a preliminary water absorption layer. This design effectively avoids urine retention on the surface, reduces the direct contact time between urine and baby's skin, and reduces the risk of skin problems such as red buttocks.

Under the surface layer, the absorbent core usually contains one or more diversion and diffusion layers. These layers are usually made of materials such as wood pulp fibers and non-woven fabrics, and have excellent diversion and diffusion properties. When urine is absorbed by the surface layer, these materials can guide the urine to spread to a wider area, ensuring that the urine is evenly distributed throughout the absorbent core. This design not only improves the water absorption efficiency of the diaper, but also avoids the discomfort caused by local over-wetting, allowing the baby to stay dry and comfortable during activities.

The bottom layer of the absorbent core usually uses a mixture of highly absorbent resin and fiber materials. These materials can quickly expand after absorbing water to form a stable gel-like structure, effectively locking urine and preventing back-seepage. At the same time, the bottom layer also bears the role of supporting the entire absorbent core, ensuring that the diaper maintains a stable shape and size during wearing. This design allows the inner surface to remain dry even if the baby wears the diaper for a long time, reducing the dampness and discomfort caused by urine residue.

The multi-layer structure design of the absorbent core of baby diapers is inseparable from the two key materials of highly absorbent resin and wood pulp fiber. These two materials have their own advantages in terms of water absorption performance, structural stability and cost-effectiveness, and together constitute the core components of the absorbent core.

Super absorbent resin is a new type of polymer material with extremely high water absorption capacity and speed. When SAP comes into contact with water, the hydrophilic groups on its molecular chain will hydrogen bond with water molecules, causing SAP to absorb water and swell rapidly. The gel-like structure formed by SAP after absorbing water has high strength and stability, which can effectively lock urine and prevent back-seepage. Therefore, SAP is widely used in the absorbent core of baby diapers and has become one of the key materials for achieving lasting dryness.

Wood pulp fiber is another important material in the absorbent core of baby diapers. Compared with SAP, wood pulp fiber has better flow conduction and diffusion properties. When urine is absorbed by SAP, wood pulp fiber can guide urine to diffuse to a wider area, ensuring that urine is evenly distributed throughout the absorbent core. This feature not only improves the water absorption efficiency of diapers, but also avoids the discomfort caused by local over-wetting. Wood pulp fiber also has certain air permeability and softness, which helps to improve the wearing comfort of diapers.

With the advancement of technology and the changing needs of consumers, the design and manufacturing of baby diaper absorbent cores are also constantly developing and innovating. The following are several optimization designs and technological innovation directions that are worth paying attention to:
The traditional absorbent core usually adopts a planar structure design, but in recent years, with the emergence of three-dimensional structure design, the water absorption performance of diapers has been significantly improved. The three-dimensional structure design can better adapt to the baby's body curve and improve the fit between the diaper and the baby's skin. This design can also increase the surface area and the number of water absorption channels of the absorbent core, further improving the water absorption speed and water absorption capacity.

In order to further improve the water absorption performance of diapers, a variety of composite absorbent materials have emerged in recent years. These materials are usually composed of SAP, wood pulp fibers, non-woven fabrics and other materials, with higher water absorption speed and stronger water locking ability. The application of composite absorbent materials allows diapers to provide better breathability and softness while maintaining long-lasting dryness.

With the continuous improvement of environmental awareness, the design and manufacturing of baby diaper absorbent cores have also begun to focus on environmental protection and sustainable development. Some manufacturers have begun to use biodegradable or recycled materials to manufacture absorbent cores to reduce pollution to the environment. They are also constantly optimizing production processes and procedures to reduce energy consumption and waste emissions.

For the majority of parents, it is important to understand the performance evaluation methods and purchase recommendations for the absorbent cores of baby diapers. Here are some practical evaluation methods and purchase recommendations:
When buying baby diapers, parents can evaluate their water absorption performance through a simple water absorption performance test. The specific method is: pour a certain amount of water into the diaper and observe its water absorption speed and water absorption capacity. You can also gently press the surface of the diaper with your hand to check whether there is water seepage or back-seepage.

In addition to water absorption performance, breathability is also one of the important indicators for measuring the quality of diapers. Parents can evaluate the breathability of diapers by observing the number and distribution of vents in the diaper and the feeling when wearing it. Diapers with good breathability can reduce the stuffiness of babies when wearing them and improve wearing comfort.

When buying baby diapers, parents should choose the right size and style based on the baby's age, weight, activity habits, etc. They should also pay attention to the brand reputation, production process, and material composition of the diapers. They should give priority to diapers from well-known brands with advanced production processes and safe and environmentally friendly material compositions.