Encapsulated PCM-SAP particle blend for diaper heat and moisture management

Overview

This proposed technology is a blended particulate system integrating commercially available microencapsulated phase change material (PCM) particles with sodium polyacrylate (SAP) in diaper absorbent cores. It manages both heat and moisture at the skin interface: SAP performs conventional liquid acquisition and retention, while PCM mitigates thermal accumulation by absorbing latent heat near its phase transition temperature of 25–35°C.

The system addresses two sources of discomfort—warmth and humidity—in one integrated blend without requiring redesign of the core architecture. Both particle populations fall in the same size range (0.2–0.8 mm) and can be co-fed through existing SAP dosing equipment, offering a low-disruption pathway to improved diaper comfort using materials already produced at commercial scale.

Technical specifications

Key features:

• PCM particles with 25–35°C phase transition, 150–250 J/g latent heat, and 0.2–0.8 mm particle size, matching SAP
• Paraffin or fatty acid cores in polymer or silica shells with established safety and regulatory profiles
• Co-blending at controlled loadings (5%, 10%, 15%, 20%) using existing particulate-handling infrastructure
• Repeatable latent heat absorption: PCM melts as skin-interface temperature rises, then re-solidifies on cooling

Validation plan:

• Screen 6–10 commercial PCMs for shell integrity in synthetic urine at 37°C over 8 hours
• Build a coupled heat-moisture model of the SAP-PCM bed
• Prototype cores and benchmark against a 0% PCM control for absorption, rewet, and strike-through
• Test finished diapers under clothed, wet conditions (32°C, 80% RH) across three sequential 60 mL insults

Target performance metrics:

• ≥1.5°C peak skin-interface temperature reduction sustained ≥30 minutes
• ≤10% absorption loss; ≤0.5 g rewet increase

Technology readiness level

The technology is at an early development stage. The concept relies on established particulate-handling infrastructure and commercially available PCMs, but the blended system has not yet been validated. A 12-month validation program covers material screening, prototype cores, finished-product testing, and preparation of a provisional patent application. Target metrics define the criteria for progressing to partner-led safety and regulatory testing.