Latent-Reactive Adhesive Composition for Low-Temperature Curing
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Solution Overview
Problem
Existing adhesive systems for bonding thermally sensitive substrates, such as anodized aluminum, leather, and textiles, face challenges with bond strength degradation under humid/heat conditions and chemical exposure, and require low-temperature curing to avoid damage.
Innovation Solution
A latent-reactive adhesive composition using a thermoplastic, isocyanate-reactive polymer dissolved in an organic solvent with a particulate isocyanate-containing crosslinker, allowing for low-temperature curing and improved bond strength resistance to moisture, heat, and chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature curing is used to achieve high bond strength, then bond strength is improved, but thermally sensitive substrates are damaged
Solution Approach 1:
The patent changes the curing temperature parameter from high temperature to low temperature (below 80°C) while maintaining high bond strength through a novel adhesive composition. The adhesive contains a polyol component with specific molecular weight (1000-10000 g/mol) and hydroxyl number (20-100 mg KOH/g) that enables effective crosslinking at low temperatures, resolving the contradiction between achieving high bond strength and avoiding thermal damage to thermally sensitive substrates like anodized aluminum and leather
Solution Approach 2:
The patent uses a composite adhesive system combining polyol, isocyanate crosslinker, and organic solvent in specific ratios. This composite formulation creates a latent-reactive adhesive that remains stable at room temperature but activates at low temperatures to form strong crosslinked bonds, enabling high bond strength without high-temperature curing that would damage sensitive substrates
2Ease of operation
If aqueous dispersion adhesive films are used to achieve easy application, then ease of operation is improved, but bond strength deteriorates under humid/heat conditions
Solution Approach 1:
The patent changes the chemical composition parameters by using organic solvent-based adhesive instead of aqueous dispersion, and by controlling the polyol molecular weight and hydroxyl number. This enables the adhesive to resist moisture penetration and maintain bond strength under humid/heat conditions while still providing easy application through film form, resolving the contradiction between ease of operation and reliability in challenging environments
Solution Approach 2:
The patent replaces long-term stable but weak aqueous dispersion systems with a latent-reactive organic adhesive that provides both easy application and long-term durability. The adhesive film can be applied easily like conventional adhesives but develops enhanced moisture and heat resistance through low-temperature crosslinking, eliminating the need for separate primers or protective coatings
3Object-affected harmful factors
If low-temperature curing is used to protect thermally sensitive substrates, then thermal damage is reduced, but bond strength and moisture resistance deteriorate
Solution Approach 1:
The patent uses a composite adhesive system with polyol (10-50 parts), isocyanate crosslinker (5-20 parts), and organic solvent (70-80 parts) in specific ratios. This composite formulation enables effective crosslinking at low temperatures below 80°C, achieving both high bond strength and moisture resistance without thermal damage to substrates. The specific molecular weight and hydroxyl number of the polyol component are critical for enabling this low-temperature high-performance curing
Solution Approach 2:
The patent optimizes the polyol parameters (molecular weight 1000-10000 g/mol, hydroxyl number 20-100 mg KOH/g) to enable effective crosslinking at low temperatures. This parameter optimization allows the adhesive to form strong, moisture-resistant crosslinked networks at temperatures below 80°C, resolving the contradiction between protecting substrates from thermal damage and achieving high bond strength and moisture resistance
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 adhesive composition maintains high bond strength and resistance to humid/heat conditions, ensuring durability and stability under challenging environmental conditions.
Implementation Method 1
a preparation for producing an adhesive, in particular a latent-reactive one, from at least one isocyanate-reactive polymer and at least one isocyanate-containing compound
Implementation Method 2
a polymer component formed from at least one polymer containing functional groups that can react with isocyanate... and a solvent component formed from at least one organic solvent, wherein the polymer component is substantially dissolved in the organic solvent
Data Source
Figure 1
AI summary
Preparation for the manufacture of an adhesive, comprising a polymer component formed from at least one thermoplastic polymer containing functional groups capable of reacting with isocyanate (component (i)), a crosslinking component formed from at least one isocyanate-containing particulate compound (component (ii)), a solvent component formed from at least one organic solvent (component (x)), wherein the polymer component is substantially dissolved in the solvent component, and the crosslinking component is substantially insoluble in both the solvent-free polymer component and the solvent component at 23 °C.