Silane-Terminated Adhesive for Wood Bonding
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Solution Overview
Problem
Current adhesives for wood bonding, such as polyvinyl acetate and isocyanate-crosslinking PU adhesives, face issues with slow setting times, limited water resistance, health hazards due to isocyanate exposure, and high costs associated with silane-crosslinking systems, which restrict their suitability for applications requiring high tensile shear strength and rapid curing.
Innovation Solution
A crosslinkable composition comprising silane-terminated prepolymers and silicone resins, which react with moisture to form a strong adhesive with high tensile shear strength, eliminating the need for toxic tin catalysts and offering improved storage stability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If isocyanate-crosslinking PU adhesives are used to achieve high mechanical strength and water resistance, then bond strength and durability are improved, but health hazards due to isocyanate exposure and storage stability worsen
Solution Approach 1:
The patent extracts and removes the harmful isocyanate component from the adhesive system while retaining the desired crosslinking functionality through silane-based chemistry. The silane-terminated polyol and silicone resin system provides crosslinking without isocyanates, eliminating sensitization and toxicity risks while maintaining bond strength and water resistance.
Solution Approach 2:
The patent changes the chemical parameters of the adhesive system by replacing isocyanate groups with silane functional groups. This parameter change transforms the curing mechanism from isocyanate-based crosslinking to silane-based condensation crosslinking, thereby eliminating health hazards while preserving mechanical performance.
2Ease of operation
If conventional polyvinyl acetate adhesives are used for wood bonding, then ease of application is maintained, but setting speed and water resistance worsen
Solution Approach 1:
The patent changes the chemical composition parameters by using silane-terminated polyols with specific molecular weights and silane content, combined with silicone resins. This enables the adhesive to cure rapidly through moisture-triggered silane condensation while maintaining easy application properties and significantly improving water resistance compared to conventional PVA adhesives.
3Speed
If silane-crosslinking systems are used to achieve rapid curing and water resistance, then setting speed and durability are improved, but cost worsens
Solution Approach 1:
The patent optimizes the parameter ratio between silane-terminated polyol and silicone resin to achieve rapid curing with controlled material costs. The specific formulation uses silane-terminated polyol (100 parts) combined with silicone resin (60-1000 parts), balancing performance and cost-effectiveness while avoiding excessive use of expensive silane components.
4Speed
If isocyanate crosslinking is accelerated through catalysis to improve curing speed, then setting speed is improved, but storage stability worsens due to side reactions
Solution Approach 1:
The patent extracts the need for catalysis by using silane-based chemistry that cures rapidly through moisture-triggered condensation without requiring catalysts. This eliminates the side reactions and stability issues associated with catalyzed isocyanate crosslinking while maintaining fast curing speeds.
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 tensile shear strength, rapid curing, and excellent adhesion, meeting DIN EN 204 standards, while being safer and more cost-effective, with formulations suitable for various substrates including wood.
Implementation Method 1
alkoxysilane-terminated polymers are able to condense with one another at room temperature, eliminating the alkoxy groups
Implementation Method 2
harden through a condensation reaction
Data Source
AI summary
The invention relates to cross-linkable materials containing (A) 100 parts by weight of compounds (A) of formula Y- [ (CR1 2)b-SiRa(OR2)3-a]x (I), (B) more than 50 parts by weight of silicone resins containing units of formula R3 c(R4O)dR5 eSiO(4-c-d-e)/2 (II), where the groups and indices have the meaning indicated in claim 1, methods for the production thereof, and the use thereof as adhesives and sealants, in particular as adhesives having high tensile shear strength inter alia for gluing wood.