Latent Catalyst Adhesive Composition for Curing Speed and Pot Life
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Solution Overview
Problem
Existing solventless polyurethane adhesives either have a long pot life with slow curing speed or fast curing speed with short pot life, making it difficult to achieve both desirable properties simultaneously.
Innovation Solution
A copolymerized crystalline latent catalyst is introduced, comprising a reaction product of crystalline acrylate monomers, tin-containing catalyst compounds, initiators, and chain transfer agents, which remains inactive at room temperature but activates at higher temperatures to accelerate curing without compromising pot life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a catalyst is added to speed up curing, then curing speed is improved, but pot life becomes short
Solution Approach 1:
The patent changes the physical state parameter of the catalyst from liquid to solid crystalline form, and controls its melting temperature parameter to be between -50°C to 50°C. This allows the catalyst to remain inactive during storage and mixing (maintaining pot life) but become active when the adhesive is applied and warms up (achieving fast curing speed).
Solution Approach 2:
The patent utilizes the phase transition of the catalyst from solid crystalline state to liquid state through melting. The catalyst is incorporated into a polymer matrix and exists in a dormant crystalline state during storage. When the adhesive is applied and temperature increases, the catalyst melts and transitions to an active liquid state, enabling fast curing without compromising pot life during handling.
2Productivity
If catalyst activity is increased to achieve fast curing, then productivity is improved, but operational flexibility deteriorates
Solution Approach 1:
The patent creates a dynamic catalyst system where the catalyst activity is not fixed but changes with temperature. The catalyst remains dormant during storage and mixing operations, providing operational flexibility. Once applied and temperature rises, the catalyst becomes active, enabling fast curing and high productivity. This dynamic behavior resolves the contradiction between productivity and ease of operation.
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 exhibits an excellent pot life and fast curing speed, maintaining operational flexibility and achieving strong bond strength development without compromising the adhesive's handling properties.
Implementation Method 1
the catalyst can be activated at a low activation temperature (e.g., less than 80° C.) to begin the curing of the adhesive composition
Implementation Method 2
a copolymerized crystalline latent catalyst includes the reaction product of: (a) at least one crystalline acrylate monomer; (b) at least one tin-containing catalyst compound
Data Source
AI summary
An adhesive composition including a reaction mixture of: (A) at least one isocyanate-containing compound; (B) at least one polyol compound; and (C) a copolymerized crystalline latent catalyst; a process for making the above adhesive composition; and a laminate structure made using the above adhesive composition.