Polypropylene Multilayer Adhesive Composition for Mechanical Recycling

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Solution Overview

Problem

Multilayer articles are difficult to recycle due to issues of yield, technical feasibility, and performance, resulting in recycled materials with unsatisfactory mechanical and physicochemical properties.

Innovation Solution

A multilayer system comprising a polypropylene layer, a hot-melt pressure-sensitive adhesive composition with styrenic block copolymers and tackifying resins, allowing for mechanical recycling and producing recycled articles with improved mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multilayer articles are made from different materials to achieve specific properties, then the functional performance is improved, but the recyclability deteriorates

Engineering Contradiction:

Improvefunctional performanceVSAvoidrecyclability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies homogeneity by making the adhesive layer composition identical to the multilayer article composition (both based on polypropylene). This allows the adhesive to be mechanically recycled together with the article layers, resolving the contradiction between functional performance (achieved through specific adhesive properties) and recyclability (achieved through material uniformity).

Inventive Principle:

Principle #33Homogeneity

2Reliability

If multilayer articles are designed for single-use to meet packaging requirements, then the functional performance is improved, but the environmental impact worsens

Engineering Contradiction:

Improvepackaging performanceVSAvoidenvironmental pollution

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter of the adhesive layer to be based on polypropylene (matching the article material) rather than traditional diverse adhesives. This parameter change enables mechanical recycling while maintaining the sealing and bonding functions required for packaging performance, thereby reducing environmental pollution from single-use articles.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If recycled materials are produced from multilayer articles, then the sustainability is improved, but the mechanical properties of recycled materials deteriorate

Engineering Contradiction:

ImprovesustainabilityVSAvoidmechanical properties

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

By making the adhesive layer homogeneous with the article layers (both polypropylene-based), the patent ensures that during mechanical recycling, all components can be processed together without separation issues. This homogeneity prevents the deterioration of mechanical properties in recycled materials, as the recycled product maintains uniform composition and structural integrity.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The patent creates a composite multilayer structure where the adhesive layer and article layers are chemically compatible (both polypropylene-based). This composite design allows the materials to work together during recycling, maintaining the mechanical strength of the recycled composite material while improving sustainability through recyclability.

Inventive Principle:

Principle #40Composite materials

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 system enables the production of recycled articles with enhanced breaking force, impact strength, and elongation at break, making it suitable for applications such as automotive components.

Implementation Method 1

Applied in the molten state, they solidify as they cool, thus forming an adhesive layer which provides the bonding between the two thin layers of thermoplastic polymeric material

Methodology Applied

Scientific EffectPhase change (solidification): Phase Change

Implementation Method 2

forming an adhesive layer which provides the bonding between the two thin layers of thermoplastic polymeric material

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS20260109842A1Recycling a multilayer system

Publication Date: 2026.04.23 BOSTIK SA(FR)

AI summary

The present invention relates to a multilayer system F1 comprising: a layer C1 comprising at least one polypropylene, an adhesive layer Ad consisting of a hot-melt pressure-sensitive adhesive composition PC, and a layer C2 comprising at least one polypropylene, said multilayer system F1 comprising at least 80% by weight of polypropylene or of a mixture of polypropylenes, with respect to the total weight of said system. The invention also relates to 10 the use of said system F1 in order to prepare a recycled article.