Blended Polypropylene Resin for High Elongation Fibers

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Solution Overview

Problem

Conventional polyolefin fibers have limited elongation, making them less stretchable and less conformable to the body, while improving elongation often compromises processing speed and efficiency in fiber production.

Innovation Solution

A blended polypropylene composition with specific molecular weight distributions and melt flow rates is developed, combining high and low molecular weight polymer components to enhance elongation while maintaining high spinning speeds, achieved through a blend of polymers with broad and narrow molecular weight distributions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If polyolefin fibers are made with higher elongation to improve body conformance and stretchability, then fiber extensibility is improved, but processing speed and spinning efficiency deteriorate

Engineering Contradiction:
Improvefiber elongationVSAvoidspinning speed
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent segments the polymer system into two distinct components: a high molecular weight polypropylene (HMW-PP) providing elongation and a low molecular weight polypropylene (LMW-PP) providing processability. This segmentation allows each component to independently contribute its advantageous properties to the fiber blend, resolving the contradiction between elongation and spinning speed

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a composite polymer system by blending HMW-PP and LMW-PP in specific ratios (30:70 to 70:30). This composite material combines the high elongation capability of HMW-PP with the high processability of LMW-PP, achieving both improved fiber extensibility and maintained spinning efficiency that neither component could achieve alone

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS7319122B2Polypropylene resin suitable for fibers and nonwovens
Publication Date: 2008.01.15 EXXONMOBIL CHEMICAL PATENTS INC

AI summary

A blended polypropylene composition, fiber, and nonwoven articles made therefrom are provided. In one aspect, the blended polypropylene composition comprises a first polymer component having a molecular weight distribution of from 2.5 to 8, and a second polymer component having a molecular weight distribution of from 1.8 to 3. The first polymer component has a melt flow rate of greater than 30 g/10 min. and the second polymer component has a melt flow rate of less than 40 g/10 min., and the blended polypropylene composition has a melt flow rate of greater than 5 g/10 min.