Polyurethane Film Softness Strength Balance

The patent applies parameter changes by precisely controlling the aromatic structure content within 500-2000 mmol/kg and using specific polyol combinations (aliphatic polyester polyol with anionic group mixed with other polyester polyols in specific ratios). This optimization of compositional parameters enables the polyurethane film to achieve both softness (300% modulus ≤20 MPa) and high strength (tear resistance ≥20 mN, abrasion resistance ≥3000 cycles), resolving the contradiction between softness and strength

The patent employs composite materials by combining multiple polyol types (aliphatic polyester polyol with anionic group, other polyester polyols) and controlling the molecular structure to include specific aromatic content. This composite approach creates a polyurethane system where different components contribute differently: the anionic polyol provides softness while the aromatic structures provide strength, achieving both soft texture and high strength simultaneously

The patent modifies the compositional parameters of conventional aqueous polyurethane emulsions by introducing specific polyol combinations (aliphatic polyester polyol with anionic group) and controlling aromatic structure content (500-2000 mmol/kg). These parameter changes transform the hard texture of conventional films into a soft texture (300% modulus ≤20 MPa) while maintaining the aqueous emulsion formulation and manufacturing simplicity

The patent applies local quality by introducing specific functional groups (anionic groups from polyester polyols) and aromatic structures at controlled levels within the polyurethane molecular structure. This localized modification of molecular characteristics changes the overall film properties from hard to soft while maintaining processability and manufacturing simplicity of conventional emulsion systems