In the manufacturing of baby diapers and adult incontinence products, Hot Melt Pressure Sensitive Adhesive (HMPSA) is often referred to as the "invisible skeleton" of the diaper.
Modern disposable diapers are composed of various dissimilar materials, including nonwoven fabrics, breathable PE films, superabsorbent polymers (SAP), fluff pulp, and elastic spandex strands. Because high-speed production lines (typically operating at 600 to 1,200 pieces per minute) cannot afford waiting time for glue drying, HMPSA—which remains permanently tacky at room temperature—has become an indispensable bonding medium.
Key Application Modules and Performance Requirements
Based on the distinct structural parts and dynamic stress requirements of a diaper, HMPSA applications are categorized into four core modules:
1. Construction Bonding
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Application Areas: Laminates the hydrophilic nonwoven top sheet, acquisition distribution layer (ADL), absorbent core (SAP mixed with fluff pulp), perforated films, and breathable PE back sheet together.
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Primary Function: Maintains structural integrity to prevent delamination, core clump breaking, or sagging caused by baby movement.
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Adhesive Requirements: High initial tack with a soft, breathable coat layer that preserves the gentle hand-feel of nonwoven fabrics.
2. Elastic Strand Attachment
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Application Areas: Secures the elastomeric spandex threads along the standing leg cuffs and elastic waistbands.
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Primary Function: Firmly locks stretched elastic strands onto the nonwoven fabric to form a snug, leak-proof barrier.
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Adhesive Requirements: Exceptional creep resistance. Must withstand continuous tensile stress under body temperature (~37°C) and urine exposure without detaching or losing tension.
3. Tape & Landing Zone Attachment
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Application Areas: Secures side tapes, frontal tapes (landing zones), and hook-and-loop fasteners.
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Primary Function: Endures frequent pulling and readjustment during diaper fitting.
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Adhesive Requirements: High shear strength and peel strength to ensure fasteners do not detach from the diaper body under stress.
4. Wetness Indicator (Specialized Application)
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Application Areas: Applied as an indicator line on the interior of the PE back sheet.
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Primary Function: Undergoes a chemical reaction (pH shift) upon contact with urine, changing color (typically from yellow to blue/green) to signal that a diaper change is needed.
Special Performance Standards for Diaper HMPSA
As personal hygiene products for infants, diapers require HMPSA to meet strict quality and safety criteria:
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Biosafety & Low Odor: Must be non-toxic, non-irritating, low VOC, and dermatologically compliant (e.g., ISO 10993). Formulated with high-purity water-white hydrogenated resins to ensure zero harsh chemical scent.
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Thermal Stability: Must resist charring, skinning, or nozzle clogging during prolonged heating in melt tanks (130°C–165°C).
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Fluid Resistance: The adhesive layer must retain its bond and avoid tacky transfer or breakdown when exposed to urine.
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High-Speed Machinability: Demonstrates optimized rheological properties to prevent splattering, stringing, or overspray at cutoff speeds exceeding 1,000 pieces per minute.
Professional Hot Melt Adhesive Solutions
-------- JCC Tianyang Group
NANCY YU
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