Primerless Polyurethane Adhesive for Glass
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Solution Overview
Problem
Current polyurethane adhesive compositions require a primer or surface pretreatment for effective adhesion to glass substrates, which complicates the bonding process and may not ensure long-term durability without additional steps.
Innovation Solution
A one-component moisture-curing polyurethane adhesive composition comprising urethane prepolymers with isocyanate moieties, catalytic amounts of catalysts, fillers, silane adhesion promoters, and monofunctional polyalkylene glycols, allowing direct adhesion to glass without pre-treatment by in-situ aliphatic endcapping, enhancing chemical compatibility and reducing moisture uptake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primer or surface pretreatment is applied to the glass substrate, then adhesion promotion is improved, but the process complexity and number of steps increase
Solution Approach 1:
The patent combines the primer composition and adhesive composition into a single integrated adhesive composition. The adhesive contains both adhesion promoters (silane coupling agents, phosphoric acid, carboxylic acid) and adhesive resins in one formulation, eliminating the need for separate primer application steps while maintaining effective adhesion to glass substrates
Solution Approach 2:
The adhesive composition serves multiple functions simultaneously: it provides adhesion promotion through silane coupling agents and phosphoric acid, maintains bonding strength through the adhesive resin matrix, and ensures durability through moisture-curing chemistry. This multi-functional formulation replaces the need for separate primer and adhesive applications
2Reliability
If a primer or surface pretreatment is applied to the glass substrate, then adhesion promotion is improved, but the time required for the bonding process increases
Solution Approach 1:
The adhesive composition is pre-formulated with adhesion promoters (silane coupling agents, phosphoric acid, carboxylic acid) already incorporated into the adhesive matrix. This preliminary incorporation of adhesion-promoting chemicals eliminates the need for separate surface treatment steps, allowing direct application to glass substrates while ensuring effective adhesion from the start
Solution Approach 2:
By merging the primer and adhesive into a single composition, the bonding process is streamlined into one application step instead of two sequential steps (primer application followed by adhesive application), directly reducing the total time required for the bonding process
3Reliability
If monofunctional polyalkylene glycols are added to the adhesive composition, then chemical compatibility and adhesion durability are improved, but the composition complexity increases
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating monofunctional polyalkylene glycols with specific molecular weight ranges (500-5000 g/mol) and controlled amounts (0.1-5.0 parts by weight per 100 parts adhesive resin). This parameter optimization enhances chemical compatibility with glass substrates and improves adhesion durability while maintaining formulation manageability
Solution Approach 2:
The adhesive composition is formulated as a composite system combining adhesive resins, silane coupling agents, phosphoric acid, carboxylic acid, and monofunctional polyalkylene glycols. Each component serves a specific function: the polyalkylene glycols provide chemical compatibility and moisture resistance, the silanes provide adhesion promotion, and the resins provide bonding strength. This composite formulation achieves superior adhesion durability through synergistic interactions among components
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 solution provides durable, primerless adhesion to glass substrates, simplifying the bonding process and maintaining adhesion performance over the vehicle's life cycle by using monofunctional polyalkylene glycols to adjust chemical compatibility and reduce moisture-induced deterioration.
Implementation Method 1
employing one or more monofunctional polyalkylene glycols. Thus, the use of monofunctional polyglycols provides a durable primerless to glass adhesion via in-situ aliphatic endcapping of the polyurethane prepolymer during adhesive processing
Implementation Method 2
curing the polyurethane adhesive composition by exposure to atmospheric moisture to form an adhesive bond between the first substrate and the second substrate
Implementation Method 3
Polyurethane adhesive compositions typically contain a polyurethane prepolymer together with a silane adhesion promoter. In order to bond the polyurethane adhesive composition to the substrate such as glass, a pre-treatment step must be carried out by applying a primer or activator to the substrate to provide durable long-term adhesion promotion of the adhesive composition
Data Source
AI summary
Disclosed are polyurethane adhesive compositions which include (a) one or more urethane prepolymers having isocyanate moieties; (b) a catalytic amount of one or more catalysts; (c) one or more fillers; (d) one or more silane adhesion promoters; and (e) one or more monofunctional polyalkylene glycols.