If you do not know the important water-absorbing polymer materials used in the commonly used diapers (or diapers), it is recommended to buy it to experience it. Original title: Ultra-thin diapers and new water-absorbing polymers.
There are three major considerations for the most important functions in diaper design: one is leak-proof, the other is dryness, and the third is to improve comfort. Below we separately describe how the product design meets the above requirements.
Since diapers began to use polymer water-absorbent resin (SAP) in the 1980s, diapers have become thinner and thinner in design, and their performance is getting better and better. Among them, SAP and non-woven fabric components have increasingly affected product performance. The bigger. It may be hard to imagine that the quality of single diaper strips in the early 1980s exceeded 100 grams (large diapers), but the quality of corresponding product strips is now less than 40 grams. This trend brings comfort to consumers, efficiency to retailers and supply chains, and opportunities and challenges for product manufacturers and raw material suppliers. The technical principle in the middle is a series of constant innovation of classic products. Whoever can seize this technological opportunity ahead of time will be more competitive in the market and lead the development of the market.
Generally designed diapers have a liquid absorption capacity of 400-550ml. Before using SAP, diapers need to use 50-60g of cellulose fibers (fluff pulp) to achieve this absorption capacity (the fluff pulp unit liquid absorption capacity is about 8ml/g). Since the unit liquid absorption capacity of SAP is above 30ml/g, after the introduction of SAP, designers began to gradually reduce the amount of fluff pulp and gradually increase the amount of SAP (from 3g per tablet to 12-13g today), while meeting the design liquid absorption capacity Claim. At present, the total weight of the absorbent core of ultra-thin products is mostly controlled at 25-28g, on the one hand, it guarantees the liquid absorption capacity to prevent leakage, and on the other hand, it can effectively control the cost.
Of course, the actual liquid content of the diapers that most users change after use does not exceed 250-300ml, but due to the uneven distribution of liquid during use, the use of liquid-absorbent materials is not complete, and the middle is already saturated or super-saturated. There is no liquid delivery and absorption at both ends of the product, so the designer will greatly exceed the liquid absorption capacity when designing the diaper. This phenomenon is more serious after the introduction of SAP. In addition to the absorption capacity, the fluff pulp fiber is also a very good liquid conduction medium. Its fiber and surface structure form a capillary structure for diversion, which is very conducive to the horizontal or even vertical direction of the liquid. Diffusion, plays a good diversion role. There is also a capillary structure between SAP particles, but the orientation of the relative fibers is much worse than that. Especially when SAP swells after water absorption and expansion, the gap between the particles will be blocked under a small pressure. Prevent the flow and conduction of liquid in the product (called gel blocking phenomenon), so the early SAP dosage is very low. The newer generation of SAP has higher gel strength after expansion through the improvement of chemical cross-linking degree and secondary surface cross-linking technology, and can maintain a certain capillary structure even after expansion in a core structure with a higher ratio. Helps liquid evacuation and absorption after reaching the product for the second and third time.
Another important leakproof member is the ADL deflector in diapers. This is a fiber structure with rapid suction, diffusion, channeling and releasing liquid. Its functional purpose is to allow the liquid to quickly diffuse to the front and back of the product when it enters the product, so as to maximize the function of the absorbent core. With a good flow guide layer, the total absorption capacity of the core design can be reduced, because the utilization rate of the entire product is increased, and the leakage prevention effect is still achieved.
Diaper design structure
Dryness refers to keeping your baby’s ass dry. It is scientifically proven that this is the best way to ensure the health of your baby’s skin and prevent diaper rash. This has also become one of the most important considerations in product design. The product is dry and requires the core to have strong liquid absorption capacity. Even when the product contains more urine, the liquid can be locked firmly under the pressure of the body weight of the child outside to prevent the liquid from flowing back and prevent moisture from remaining. The product surface layer gathers water vapor from the surface layer to the product core in one direction. At the same time, the breathability of the diaper bottom film has become the standard configuration of the product, helping the moisture to dissipate from the outside of the product.
Dryness is the overall performance of the product, and various components in the product need to cooperate to achieve the design purpose. SAP must have a high degree of CRC and AUL for urine. During the use period (overnight is 12 hours), there must be no performance degradation and dissolution. The rate of water absorption and the flow rate of the product must match. The surface layer of the product is in direct contact with the baby’s skin. Good liquid permeability and dryness of the fiber surface are very important. This is related to the type of fiber and the choice of hydrophilic oil on the surface. The diversion layer can not only promote a reasonable liquid distribution in the product, but also construct favorable structural characteristics through the selection of fiber types and sizes (structural density, ratio, capillary connectivity), and guide liquid and moisture to the product core in one direction. More and more high-end products use multi-layer composite fiber materials as the surface layer or flow guide layer, the purpose is to build a favorable capillary structure to guide the flow, diffusion, absorption and reverse osmosis of liquid in the product.
The most important thing about comfort is that the diaper can perfectly fit the baby’s body when it is worn, so that the liquid cannot leak to achieve the purpose of preventing leakage. The elastic material used in diapers is for this purpose, and the exquisiteness of elastic material application is proportional to the high-end level of the product. The rise of pull-up pants is also due to the advancement of elastic materials that makes it possible to put on and take off diapers. The products in the Asia-Pacific region pay more attention to the choice of the product surface layer in contact with the skin than the European and American products. At the same time, this is another focus of product comfort. The use of various multi-layer and 3D structures has made Japan, South Korea and China high-end. The surface material of diaper products looks more high-end than European and American products.
The latest improvement in comfort is the use of ultra-thin products and ultra-thin cores. This improvement brings diaper products closer to underwear, completely eliminating the use of fluff pulp can make the product thinner and lighter, after absorbing liquid The core shape and strength are still maintained.
However, after removing the fluff pulp, the liquid conductivity of the product must be completed by other synthetic fibers or dust-free paper materials. These fluffy conductivity fibers/SAP composite cores have developed rapidly in the domestic market in the past two or three years. The scale and complexity of the category greatly surpassed the preliminary research and development of the two major US industry giants and the products launched by a European company. Compared with the traditional fluff pulp/SAP water-absorbing core, the requirements of this type of composite core product for SAP, as well as its liquid diffusion and product utilization improvement, are all new issues. China SAP suppliers for this purpose A lot of innovative work has been done in this regard, and I believe that it can further promote the improvement of SAP performance and the development of the industry.