Graft-Modified Polypropylene Laminate for Adhesion and Barrier
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Solution Overview
Problem
Polyolefin-based resins used in packaging materials face challenges with poor adhesion to inorganic layers, leading to delamination issues and a lack of both effective gas barrier properties and aesthetic appeal, such as glitter feeling, in packaging films.
Innovation Solution
A laminate structure comprising a polyolefin resin layer, a graft-modified deposition layer, and an inorganic layer, where the deposition layer is composed of isotactic polypropylene and propylene-based copolymers with a graft monomer, enhancing adhesion and providing both delamination resistance and a glossy appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyolefin-based resin is used as packaging material, then cost is reduced and moldability is improved, but adhesion to inorganic layer deteriorates causing delamination
Solution Approach 1:
The invention changes the chemical composition parameters of the resin layer by introducing graft-modified polypropylene containing carboxylic acid groups. This chemical modification enables strong chelation with aluminum ions in the inorganic layer, transforming the adhesion mechanism from physical bonding to chemical bonding, thereby resolving the adhesion problem while maintaining polyolefin-based resin benefits
Solution Approach 2:
The invention creates a composite material system combining polyolefin-based resin with graft-modified polypropylene containing metal chelating groups. This composite structure integrates the excellent moldability of polyolefin with the strong adhesion capability of chelating groups, achieving both ease of manufacture and high reliability
2Reliability
If aluminum foil or aluminum-deposited film is used to provide gas barrier and light-shielding functions, then gas barrier properties are improved, but delamination occurs due to poor adhesion
Solution Approach 1:
The graft-modified polypropylene acts as an intermediary layer between the polyolefin-based resin and the inorganic aluminum layer. The carboxylic acid groups in this intermediary layer form strong chelation bonds with aluminum ions, bridging the two layers and preventing delamination while maintaining the gas barrier function of the aluminum layer
3Illumination intensity
If packaging bags require metallic appearance and glitter feeling, then aesthetic appeal is improved, but delamination resistance deteriorates
Solution Approach 1:
The invention changes the surface chemical properties of the resin layer through graft modification, introducing carboxylic acid groups that provide strong adhesion to the aluminum layer. This enables the aluminum layer to be firmly bonded while maintaining its light-reflecting properties, achieving both aesthetic appeal and delamination resistance
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 laminate exhibits strong interlaminar peel strength, excellent gas barrier properties, and a glossy inorganic layer surface, addressing the issues of delamination and aesthetic appeal while maintaining flexibility and durability.
Implementation Method 1
a part or all of the isotactic polypropylene (A) and, optionally, a part or all of the propylene-based copolymer (B) has been graft-modified with a graft monomer (C)
Implementation Method 2
the layer (II) for deposition comprises a composition (P) for a layer for deposition and polypropylene (D)... a part or all of the isotactic polypropylene (A)... has been graft-modified with a graft monomer (C)... (C) a graft monomer, preferably an unsaturated carboxylic acid and/or its derivative (C)
Data Source
AI summary
The present invention addresses the problem of providing a laminate having sufficient delamination prevention performance and simultaneously having an inorganic layer surface imparted with brightness. The laminate of the present invention is a laminate having a polyolef in-based resin layer, a layer for deposition and an inorganic layer in this order, wherein the layer for deposition includes a composition (P) for a layer for deposition and polypropylene (D), the composition (P) for a layer for deposition is obtained by melt-kneading 30 to 85% by weight of isotactic polypropylene (A) and 70 to 15% by weight of a propylene-based copolymer (B), a part or all of the isotactic polypropylene (A) and/or the propylene-based copolymer (B) has been graft-modified with a graft monomer (C), and the propylene-based copolymer (B) contains 45 to 89% by mol of constituent units derived from propylene and 11 to 55% by mol of constituent units derived from at least one α-olefin selected from ethylene and α-olefins of 4 to 20 carbon atoms.