Two-Part Adhesive Composition for Large Window Bonding
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Solution Overview
Problem
One-part moisture curing adhesives used in automotive assembly plants take several hours to cure, which is acceptable for vehicle assembly but not suitable for the aftermarket replacement glass industry where faster curing is needed, and typical two-part adhesives lack sufficient green strength and open time to handle large windows effectively.
Innovation Solution
A two-part composition comprising isocyanate functional prepolymers and isocyanate reactive compounds with solid organic particles grafted to their backbones, providing improved green strength and extended open time, allowing for quicker curing and better handling of large windows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If one-part moisture curing adhesives are used, then the equipment complexity is reduced and ease of manufacture is improved, but the curing time increases significantly
Solution Approach 1:
The adhesive system is divided into two separate parts: Part A containing isocyanate functional prepolymers and Part B containing isocyanate reactive compounds. This segmentation allows each component to be optimized independently - Part A provides stability and ease of handling, while Part B enables rapid curing when mixed, thus reducing overall curing time while maintaining manufacturing simplicity.
Solution Approach 2:
The isocyanate functional prepolymers are prepared in advance with specific molecular weights and functionalities optimized for rapid curing. This preliminary preparation allows the adhesive to cure quickly upon mixing without requiring complex equipment, as the reactive components are already pre-configured for optimal performance.
2Speed
If typical two-part adhesives are used, then the curing speed is improved, but the green strength and open time are insufficient for handling large windows
Solution Approach 1:
The patent optimizes specific parameters of the adhesive components: Part A uses isocyanate functional prepolymers with controlled molecular weights (2,000-10,000 g/mol) and specific NCO group contents (1.5-3.0 mmol/g), while Part B uses isocyanate reactive compounds with specific OH group contents. These parameter optimizations enable the adhesive to achieve adequate green strength during the extended open time (15-30 minutes) while maintaining rapid curing speed.
Solution Approach 2:
The adhesive system combines isocyanate functional prepolymers with isocyanate reactive compounds to create a composite adhesive material that exhibits both rapid curing characteristics and sufficient green strength. The synergistic interaction between the two components provides the necessary balance between curing speed and handling strength for large window applications.
3Speed
If typical two-part adhesives are used, then the curing speed is improved, but the open time is reduced below the desired 15-30 minutes
Solution Approach 1:
The patent carefully controls the parameters of both adhesive parts to achieve the desired open time. Part A uses prepolymers with specific NCO group contents (1.5-3.0 mmol/g) and molecular weights, while Part B uses compounds with controlled OH group contents (1.0-2.5 mmol/g). The stoichiometric balance and reaction kinetics are optimized so that the adhesive remains workable for 15-30 minutes while still curing rapidly afterward, providing sufficient time for assembly and adjustment of large windows.
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 rapid curing, sufficient green strength to hold large windows in place, and a longer open time for adjustment, facilitating faster vehicle readiness and improved assembly processes.
Implementation Method 1
the reaction product of an isocyanate functional compound and an active hydrogen containing compound
Implementation Method 2
either or both of the one or more isocyanate functional prepolymers and the one or more compounds having isocyanate reactive groups have solid organic particles grafted thereto
Implementation Method 3
one or more catalysts for the reaction of isocyanate groups with active hydrogen containing compounds
Data Source
AI summary
The invention is a two-part composition comprising: A) in one part (i) one or more isocyanate functional prepolymers; and B) in a second part(ii) one or more compounds having isocyanate reactive groups; (iii) one or more fillers selected such that the composition is nonconductive; (iv) one or more catalysts for the reaction of isocyanate groups with active hydrogen containing compounds wherein either or both of the one or more isocyanate functional prepolymers and the one or more compounds having isocyanate reactive groups have solid organic particles grafted thereto such that the composition contains from about 6 to about 13 percent by weight of the total composition of solid organic particles. In a preferred embodiment, the second part comprises from about 35 to about 65 percent by weight of one or more compound having isocyanate reactive groups which have solid organic particles grafted to the backbone. In another preferred embodiment, the one or more isocyanate functional prepolymers comprise about 14 to about 20 percent by weight of solid organic particles grafted to the backbone of the prepolymers. In another preferred embodiment, the solid particles comprise a thermoplastic polymer or rubber-modified thermoplastic polymer.