Grafted Ethylene-Alpha-Olefin Interpolymers for Hard-to-Bond Substrates
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Solution Overview
Problem
Conventional hot melt adhesives (HMAs) based on metallocene or single-site catalyzed olefin polymers or EVA have limited adhesion to 'hard to bond' substrates such as surface-treated and coated cardboards with low or no porosity, which are commonly used in packaging.
Innovation Solution
Development of a composition comprising acid and/or anhydride grafted ethylene/alpha-olefin interpolymer with specific properties, including a number of grafts per polymer chain ≥ 1.80 and melt viscosity ≤ 50,000 mPa·s, which improves adhesion to UV varnished and dense corrugated cardboard substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional hot melt adhesives (HMA) based on metallocene or single-site catalyzed olefin polymers or EVA are used, then the adhesive formulation is simple and easy to manufacture, but the adhesion to hard to bond substrates is limited
Solution Approach 1:
The patent changes the chemical parameters of the adhesive by using ethylene/alpha-olefin interpolymer with specific graft levels (≥1.80 grafts per chain) and controlled molecular weight (Mw/Mn ≤ 2.00), rather than conventional homogeneous polymers. This parameter change enables improved adhesion to hard to bond substrates while maintaining formulation simplicity.
Solution Approach 2:
The patent employs a composite adhesive system combining ethylene/alpha-olefin interpolymer with specific functional groups (carboxylic acid, anhydride, or ester) grafted at controlled levels. This composite approach enhances adhesion to hard to bond substrates while keeping the overall formulation relatively simple.
2Strength
If acid and/or anhydride grafted ethylene/alpha-olefin interpolymer with high graft levels (≥1.80) is used, then adhesion to hard to bond substrates is improved, but melt viscosity increases
Solution Approach 1:
The patent optimizes the parameter of graft level to be ≥1.80 per chain while simultaneously controlling the molecular weight distribution (Mw/Mn ≤ 2.00) and ensuring melt viscosity ≤50,000 mPa·s at 177°C. This coordinated parameter change achieves improved adhesion without excessive viscosity increase.
Solution Approach 2:
The patent creates a dynamic balance in the adhesive formulation where the interpolymer structure provides both high graft levels for adhesion and controlled melt viscosity through specific molecular weight distribution. The adhesive system dynamically adjusts its properties during processing and bonding.
3Strength
If acid and/or anhydride grafted ethylene/alpha-olefin interpolymer with high graft levels (≥1.80) is used, then adhesion to hard to bond substrates is improved, but polymer synthesis complexity increases
Solution Approach 1:
The patent specifies precise synthesis parameters including graft level (≥1.80), molecular weight distribution (Mw/Mn ≤ 2.00), and melt viscosity (≤50,000 mPa·s at 177°C). By controlling these parameters, the complex interpolymer structure can be manufactured using conventional techniques with standardized procedures.
Solution Approach 2:
The patent replaces complex multi-step synthesis procedures with a single-stage grafting process that achieves the desired interpolymer structure. This substitution of the synthesis approach maintains manufacturing feasibility while producing the high-performance adhesive material.
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 new adhesive composition demonstrates enhanced adhesion and heat stress resistance, with fiber tear percentages ranging from 70% to 100% across various temperatures, outperforming conventional formulations on 'hard to bond' substrates.
Implementation Method 1
a composition comprising an acid and/or anhydride grafted ethylene/alpha-olefin interpolymer
Data Source
Figure 1
AI summary
A composition comprising an acid and/or anhydride grafted ethylene/alpha-olefin interpolymer that comprises the following properties: A) number of grafts per polymer chain ≥ 1.80, and B) melt viscosity (at 177℃) ≤ 50,000 mPa.s.