Room Temperature Urethane Adhesive Composition for Automotive Bonding
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Solution Overview
Problem
Current high modulus urethane adhesive compositions require heating during manufacturing and application, making them difficult to pump at room temperature and necessitating the use of paint primers on car body structures, which limits their usability and performance.
Innovation Solution
A urethane adhesive composition comprising a urethane prepolymer resin, aromatic or aliphatic polyisocyanates, catalysts such as organic amines or metal carboxylates, and fillers like carbon black, which can be produced and pumped at room temperature without heating, enabling high modulus performance and direct adhesion to painted metal substrates without primers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid polymer resins (crystalline polyester resins and/or acrylic resins) are used to achieve high modulus urethane adhesive compositions, then high modulus performance is improved, but heating during manufacturing and application is required and viscosity increases making pumping difficult
Solution Approach 1:
The patent changes the chemical composition parameters by using flexible polymer resins instead of rigid ones, and by incorporating specific catalysts (organic amines and/or metal carboxylates) to enable moisture curing. This allows the adhesive to achieve high modulus performance while remaining pumpable at room temperature without heating, as the catalyst system enables the reaction to proceed at lower temperatures.
Solution Approach 2:
The patent creates a composite adhesive system combining flexible polymer resins with polyisocyanates and catalysts. This composite formulation achieves the desired high modulus performance through the synergistic interaction of components, while the flexible resin base maintains low viscosity for easy pumping at room temperature.
2Strength
If rigid polymer resins are used to achieve high modulus performance, then storage modulus is improved, but heating during manufacturing is required
Solution Approach 1:
The patent changes the curing mechanism by introducing moisture-cure catalysts (organic amines and/or metal carboxylates) that enable the polyisocyanate to react with atmospheric moisture. This allows the adhesive to cure at room temperature during manufacturing and application, eliminating the need for heating while achieving high storage modulus performance through the crosslinked network formed by moisture curing.
3Strength
If rigid polymer resins are used to achieve high modulus performance, then shear modulus is improved, but viscosity increases making the composition difficult to pump
Solution Approach 1:
The patent changes the molecular structure parameters by using flexible polymer resins with appropriate molecular weight and chain flexibility. This maintains low viscosity for easy pumping while the catalyst system (organic amines and/or metal carboxylates) enables efficient crosslinking to achieve high shear modulus in the cured state, resolving the contradiction between processability and final strength.
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 high storage and shear modulus, is pump transferable at room temperature, and exhibits excellent adhesion and sag resistance, eliminating the need for heating and primers, thereby enhancing NVH performance and application efficiency.
Implementation Method 1
catalysts such as organic amines and metal carboxylates for moisture cure
Implementation Method 2
urethane adhesive composition comprising a urethane prepolymer resin, a polyisocyanate
Data Source
AI summary
The invention relates to a urethane adhesive composition having high modulus and is pump transferable at room temperature.