Polyurethane Adhesive Composition for Polyethylene Metal Laminates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing adhesive compositions fail to provide adequate bond strength, heat seal strength, and boil in bag resistance for laminates made of polyethylene and metal substrates, particularly in solvent-free and aqueous formulations.
Innovation Solution
A polyurethane adhesive composition comprising 70-96% polyurethane dispersion, 1-20% epoxy resin, and 0.5-15% aliphatic amine crosslinker, with specific ratios of monomeric aromatic diisocyanates, polyether polyols, and ionic surfactants, forming a stable and solvent-free mixture for enhanced bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesive compositions are used to bond polyethylene and metal substrates, then bonding can be achieved, but bond strength, heat seal strength, and boil in bag resistance are insufficient
Solution Approach 1:
The patent uses a composite adhesive system combining polyurethane dispersion (70-96%), epoxy resin (1-20%), and aliphatic amine crosslinker (0.5-15%). This multi-component composite formulation creates synergistic effects where polyurethane provides initial adhesion to polyethylene, epoxy enhances strength and heat resistance, and the crosslinker forms a three-dimensional network structure that improves overall bond strength and boil in bag resistance simultaneously.
Solution Approach 2:
The patent optimizes specific parameter ranges for each component: polyurethane dispersion (70-96%), epoxy resin (1-20%), and aliphatic amine crosslinker (0.5-15%). These parameter adjustments ensure the adhesive achieves adequate bond strength while maintaining reliability under boiling conditions. The controlled parameter ranges prevent excessive crosslinking that could brittleness while ensuring sufficient crosslink density for heat and moisture resistance.
2Object-affected harmful factors
If solvent-free and aqueous formulations are used for environmental and safety reasons, then health and safety requirements are met, but adhesive performance in bond strength and heat seal strength deteriorates
Solution Approach 1:
The patent maintains an aqueous formulation with water as the continuous phase while adjusting the solid content parameters of polyurethane dispersion (70-96%) to ensure adequate viscosity and adhesion. The epoxy resin (1-20%) and crosslinker (0.5-15%) ratios are optimized to achieve proper crosslinking density without requiring organic solvents, thereby maintaining heat seal strength while meeting environmental and safety requirements.
Solution Approach 2:
The combination of polyurethane dispersion, epoxy resin, and aliphatic amine crosslinker creates a composite system where each component compensates for the limitations of aqueous formulation. The epoxy-resin crosslinker system provides robust heat seal strength and chemical resistance that compensates for the lower solubility and adhesion typically associated with water-based adhesives, while the polyurethane matrix ensures compatibility with polyethylene substrates.
3Strength
If polyurethane dispersion with ionic surfactant and polyamine is used, then adhesion to polyethylene is improved, but formulation complexity increases
Solution Approach 1:
The patent combines multiple functional components into a single polyurethane dispersion formulation: the polyurethane prepolymer provides base adhesion, ionic surfactant (0.5-10%) enhances wetting and dispersion stability, and polyamine (0.1-8%) acts as both chain extender and adhesion promoter. This merged formulation simplifies application by providing all necessary adhesion-enhancing functions in one component, reducing the need for separate additives or pretreatment steps despite the multi-component nature of the final adhesive system.
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 composition achieves improved bond strength, heat seal strength, and boil in bag resistance, ensuring effective bonding between polyethylene and metal substrates while maintaining an aqueous and solvent-free formulation.
Implementation Method 1
the polyurethane dispersion comprises a polyurethane prepolymer, and by dry weight based on total dry weight of the polyurethane dispersion, from 0.5% to 10%, an ionic surfactant
Implementation Method 2
from 0.5% to 15%, an aliphatic amine crosslinker; from 1% to 20%, an epoxy resin
Implementation Method 3
The present invention provides an adhesive composition comprising, by dry weight based on total dry weight of the adhesive composition, from 70% to 96%, a polyurethane dispersion, from 1% to 20%, an epoxy resin, and from 0.5% to 15%, an aliphatic amine crosslinker
Data Source
AI summary
The present invention provides an adhesive composition comprising, by dry weight based on total dry weight of the adhesive composition, from 70% to 96%, a polyurethane dispersion, from 1% to 20%, an epoxy resin, and from 0.5% to 15%, an aliphatic amine crosslinker. It further provides a laminate comprising the adhesive composition.