Polyamide-Olefinic Composite Adhesion via Polyethyleneimine
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Solution Overview
Problem
The adhesion between olefinic/vinyl aromatic polymers and modified polyamides, or between modified olefinic/vinyl aromatic polymers and polyamides, is insufficient when stored at elevated temperatures and high humidity, leading to a loss of mechanical properties and adhesion strength.
Innovation Solution
Incorporating polyethyleneimines or their copolymers into the polyamide or olefinic/vinyl aromatic polymer moulding compounds to enhance adhesion strength between the sections, without compromising the mechanical properties, and maintaining adhesion even under heat and moisture exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If olefinic/vinyl aromatic polymers are added to polyamide or grafted with carboxylic acid/anhydride groups to improve adhesion, then adhesion strength is improved initially, but adhesion strength is lost after storage at elevated temperature and humidity
Solution Approach 1:
The patent changes the chemical parameter by introducing polyethyleneimine with specific functional groups (amine groups) that provide both initial adhesion strength and long-term stability. The polyethyleneimine contains primary, secondary, and tertiary amine groups that can form strong bonds with both polyamide and olefinic/vinyl aromatic polymers, and this chemical composition change maintains adhesion stability after storage at elevated temperature and humidity.
Solution Approach 2:
The patent creates a composite adhesion system by combining polyethyleneimine with the existing polyamide and olefinic/vinyl aromatic polymer components. This composite approach allows the polyethyleneimine to act as a bridge material that maintains compatibility and adhesion between the two different polymer sections under various storage conditions.
2Strength
If polyamide is modified with flexible component to improve adhesion, then adhesion is improved, but mechanical properties and processability are lost
Solution Approach 1:
The patent applies local quality by introducing polyethyleneimine specifically at the interface between polyamide and olefinic/vinyl aromatic polymer sections, rather than modifying the bulk polyamide throughout. This localized addition of 0.1-5% polyethyleneimine provides adhesion enhancement at the critical bonding zone while preserving the mechanical properties and processability of the main polyamide structure.
3Strength
If modified olefinic/vinyl aromatic polymers are used to improve adhesion, then adhesion is improved initially, but adhesion strength decreases quickly after storage at 70°C and 62% relative humidity
Solution Approach 1:
The patent introduces polyethyleneimine as an intermediary substance that mediates the bonding between polyamide and olefinic/vinyl aromatic polymers. The polyethyleneimine contains functional groups that can interact with both materials, creating a stable intermediate bonding layer that prevents the quick adhesion loss observed with directly modified olefinic/vinyl aromatic polymers under storage conditions.
Data Source
AI summary
A composite containing directly adjoining and firmly bonded sections (I) and (II) of the following type:(I) section, formed from a thermoplastic moulding compound FM-1 containing at least one polyamide (A) and optionally fillers and reinforcing materials (C) and additives (D);(II) section, formed from a thermoplastic moulding compound containing at least one olefinic and/or vinyl aromatic polymer (E) and optionally fillers and reinforcing agents (F), plasticisers (G) and additives (H);wherein the moulding compound FM-1 or FM-2 contains 0.1 to 5.0 percent by weight of polyethyleneimine (B) or a copolymer or derivative thereof and a method for producing such composites.