Paper Diaper – Sodium Polyacrylate inside

    sodium polyacrylate in diapers
    Paper diapers

    As a website dedicated to introducing superabsorbent polymer (SAP), it is necessary to talk about the main use of SAP: diapers.

    As disposable diaper products, diapers are suitable for urine absorption by infants, young children, the elderly and other people.

    It is composed of an absorbent layer, a leak-proof layer, a breathable outer layer and a Velcro strap, which can quickly absorb urine, prevent leakage, and keep the skin dry.

    The functional material of the absorbent layer in diapers is sodium polyacrylate.

    Sodium polyacrylate absorbs quickly and turns it into a gel when it comes into contact with urine. This allows the diaper to effectively lock in liquid and avoid urine backflow and leakage while maintaining a dry feel.

    Main indicators

    The quality of SAP directly determines the overall effect of diapers.

    When purchasing SAP, in addition to considering price, diaper manufacturers will also consider the following important parameters:

    Absorbent rate. The maximum weight of saline solution can be absorbed per unit weight of SAP.

    This value determines how much urine the diaper absorbs.

    Absorption under pressure and retention capacity after centrifugation. The SAP’s ability to absorb saline is tested in a pressurized or centrifuged environment.This value determines the diaper’s ability to absorb urine under movement or squeezing.

    Liquid Permeability. This value tests the ability of SAP to be absorbed evenly after encountering urine. If this indicator is unqualified, the diaper will not be able to absorb urine evenly throughout the entire diaper, resulting in bulging.

    Residual Monomer. Residual amount of acrylic acid.Residues of acrylic acid can irritate the skin and cause symptoms of rash.

    Paper Diapers on Amazon (recommended)

    Statement: This webpage contains affiliate links to Amazon. As an Amazon Associate, we earn from qualifying purchases. Thank you for your support.

    Amazon Brand - Mama Bear Gentle Touch Diapers, Hypoallergenic, Size 2, White, 184 Count (4 packs of 46)

    Amazon Brand – Mama Bear Gentle Touch Diapers, Hypoallergenic, Size 2, White, 184 Count (4 packs of 46)

    • IN THE BOX: Mama Bear Gentle Touch diapers for babies; size 2; (4 packs of 46 diapers each, 184 total)
    • HYPOALLERGENIC & PARABEN-FREE: Dermatologist tested and hypoallergenic for baby’s sensitive skin; Free of chlorine bleaching, perfumes, lotions, parabens, and phthalates
    • LEAKAGE PROTECTION: Up to 12 hours of protection; Wetness Indicator shows when it’s time for a change
    • COMFORT FIT: Thin design with flexible fit for comfortable movement
    • BREATHEABLE COVER: Outer cover helps keep baby’s skin dry and healthy
    • SIZING RECOMMENDATION: First-time users, consider getting the size your child currently wears; if the fit is snug, size up
    • An Amazon brand; Bags contain 20% Post Consumer Recycled Materials

    Depend Night Defense Adult Incontinence Underwear for Men, Disposable, Overnight, Large, Grey, 56 Count (4 Packs of 14), Packaging May Vary

    • Depend Night Defense Adult Incontinence Underwear for Men, large (35–43″ waist), 56 count (4 packs of 14)
    • Overnight Absorbency: Night Defense features a super absorbent core which absorbs 25x its weight* and turns liquid into gel, locking wetness in place for all-night comfort (*weight of super absorbent material)
    • Overnight Protection: Our men’s bladder leakage underwear delivers up to 12 hours overnight protection for heavy bladder leaks
    • 2x Drier Than Before: Depend’s improved liner wicks wetness away from your skin to help keep you dry
    • Odor Control: Our overnight underwear for bladder leaks helps neutralize and lock in odors by turning liquid into gel
    • Comfort: Depend Night Defense is unlike bulky adult diapers and features a discreet fit with soft, smooth fabric
    • Secure Fit: Depend Night Defense has a high-performance waistband to help keep your underwear securely in place
    • Depend adult incontinence underwear for men is HSA/FSA-eligible in the US
    • Depend’s packaging and product may vary

    How to Choose Diapers


    The breathability of diapers depends on the tiny holes in them that are invisible to the naked eye.

    Diapers with poor breathability can make the skin moist (even if the diaper is not wet), causing skin discomfort and rashes.

    Anti-reverse osmosis

    Anti-reverse osmosis diapers can seep in even if there is a lot of urine, but the surface will still be dry.

    The anti-reverse osmosis of diapers is mainly determined by the surface layer of the diaper.

    The top layer is the layer of the diaper that contacts the skin. It allows liquid to pass through quickly while preventing liquid from seeping back. Just like a semi-permeable membrane, it is easy to pass through, but not easy to seep back from the other side. With the top layer, the diaper can keep the contact surface dry, soft and comfortable

    Absorption capacity

    Obviously, absorption is a very important symptom of diapers. The amount of absorption depends on the absorbent core inside the diaper.

    It is the most important and core component of diapers. It is mainly composed of fluff pulp and water-absorbent resin (SAP), which is used to absorb and condense urine.

    The early water-absorbent cores mainly focused on the amount of water absorbed, without zoning the materials, and were prone to lumps.

    Later, dust-free cloth, non-woven fabric, hot melt adhesive and other materials were added to the absorbent core, and the entire core was also partitioned. Although this new diaper increases the cost, it is thinner and less prone to lumps.

    Production Process

    Diversion layer

    The diversion layer is located between the topsheet and the absorbent core and is a longitudinally arranged fiber that temporarily stores moisture and transports it along the fiber. Its function is to make the diaper absorb liquid quickly, effectively and evenly.

    The discharge of urine comes into contact with the diaper from one place. A good diaper will quickly disperse the liquid evenly throughout the diaper without causing excessive accumulation in one place. This is the function of the diversion layer.

    Leak-proof sides

    Its main function is to help prevent and block side leakage of urine.

    Not only can it help isolate urine and soft feces, ensuring all aspects of hygiene, but it can also effectively prevent redness, itching and other symptoms in the buttocks.

    Base film

    The bottom film is a breathable microporous film on the bottom of the diaper that can be breathable and impermeable.

    This is because the minimum diameter of water droplets is 20µm, the diameter of water vapor molecules is 0.0004µm, and the diameter of micropores is between the two.


    Try to choose diapers with wetness indicators. The diapers are marked with patterns. When wet, the color becomes lighter, making it easier to change diapers in time and avoid being irritated by urine for a long time.


    The softness of the inside of a diaper determines whether it is comfortable to wear.

    We can touch the inside of the diaper with our hands, and we can find diapers that can be tested by ourselves.

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