MAH-Grafted LLDPE Composition for High Melt Index Adhesion

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Solution Overview

Problem

Existing maleic anhydride grafted linear low-density polyethylenes (LLDPEs) exhibit low melt index and limited adhesion over a wide temperature range, which hinders their effectiveness in adhesive applications.

Innovation Solution

Development of LLDPEs grafted with maleic anhydride (MAH-g-LLDPE) with a melt index of 250 to 800 g/10 minutes and 0.01 to 3 weight percent maleic anhydride content, produced through a process involving melting and extrusion without a free radical initiator, enhancing adhesion properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional maleic anhydride grafted LLDPE is produced using existing methods, then the polymer can be manufactured, but the melt index remains low (below 37 g/10 min) and adhesion is limited over temperature range

Engineering Contradiction:
Improvemelt indexVSAvoidadhesion performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the grafting conditions, specifically using a maleic anhydride concentration of 0.01 to 3 weight percent and controlling the extrusion temperature and residence time to achieve a melt index of 250 to 800 g/10 minutes while maintaining adhesion properties over a wide temperature range

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by grafting maleic anhydride onto LLDPE to produce MAH-g-LLDPE with specific properties (0.01 to 3 wt% maleic anhydride content, melt index 250-800 g/10 min), which combines the benefits of improved processability with enhanced adhesion performance

Inventive Principle:
Principle #40Composite materials

2Reliability

If the maleic anhydride content is increased to improve adhesion, then bonding performance improves, but the melt index may become unmanageably high affecting processing

Engineering Contradiction:
ImproveadhesionVSAvoidmelt index control
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent optimizes the maleic anhydride content parameter to a specific range of 0.01 to 3 weight percent, which provides sufficient adhesion improvement while maintaining the melt index within the controllable range of 250 to 800 g/10 minutes, balancing performance and processability

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The MAH-g-LLDPE demonstrates improved adhesion to various surfaces and enhances the properties of hot melt adhesives over a wide temperature range, offering better cohesive strength and bonding performance.

Implementation Method 1

contacting the molten LLDPE with the maleic anhydride in the extruder at conditions effective to increase the melt index (MI) of the LLDPE and to form the MAH-g-LLDPE

Methodology Applied
Scientific EffectGrafting reaction: Chemical Bonding

Implementation Method 2

melting a LLDPE in an extruder to form a molten LLDPE

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4722301A2Maleic anhydride grafted lldpe having high melt index
Publication Date: 2026.04.08 WESTLAKE LONGVIEW CORP

AI summary

Disclosed is a linear low-density polyethylene grafted with maleic anhydride (MAH-g-LLDPE). The MAH-g-LLDPE has a unique combination of properties including a low density and a high melt index.