One-Component Sealant for Working Joints
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Solution Overview
Problem
Conventional one-component curable compositions with polyoxyalkylene-based polymers and reactive silicon groups are inadequate in terms of compression recovery rate, displacement conformance, and durability for working joints in buildings, particularly experiencing stress differentials and cracking due to large displacements during curing.
Innovation Solution
A one-component curable composition for working joints, comprising a polyoxyalkylene-based polymer with 1.2 to 5 reactive silicon groups, a silane compound obtained by partial condensation of an aminosilane, and a tetravalent organotin compound, which enhances curing properties and mechanical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a one-component sealant is used for working joints with large displacement, then workability is improved (no mixing required), but stress differential occurs between surface and internal portions during curing, leading to cracking
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific silane compounds (obtained by partial condensation of aminosilane) and tetravalent organotin compounds in controlled amounts. These compositional changes alter the curing characteristics to reduce stress differential during displacement, enabling one-component sealants to withstand large joint movements without cracking while maintaining ease of application.
Solution Approach 2:
The patent creates a composite curable composition by combining polyoxyalkylene-based polymers with reactive silicon groups, silane compounds, and tetravalent organotin compounds. This composite formulation synergistically improves both workability and cracking resistance, allowing the sealant to function effectively as a one-component system in working joints with large displacement capabilities.
2Ease of operation
If conventional one-component curable compositions are used, then ease of application is maintained, but compression recovery rate and displacement conformance are insufficient
Solution Approach 1:
The patent optimizes compositional parameters by specifying precise amounts of silane compounds and tetravalent organotin compounds. These parameter modifications enhance the compression recovery rate and displacement conformance of the cured sealant while preserving the ease of application characteristic of one-component systems.
Solution Approach 2:
The composite formulation combining polyoxyalkylene-based polymers, silane compounds, and tetravalent organotin compounds creates a material with superior compression recovery properties and displacement conformance, while maintaining the simplified application process of one-component sealants.
3Device complexity
If conventional one-component curable compositions are used, then simplicity is maintained, but durability for working joints does not meet classification 9030
Solution Approach 1:
The patent adjusts chemical composition parameters by incorporating specific ratios of silane compounds and tetravalent organotin compounds. These parameter changes enhance the durability of the cured sealant to meet classification 9030 for working joints, while maintaining the simplicity of one-component application.
Solution Approach 2:
The composite curable composition integrates polyoxyalkylene-based polymers with reactive silicon groups, silane compounds, and tetravalent organotin compounds to achieve durability meeting classification 9030, while preserving the operational simplicity of one-component sealants.
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 excellent compression recovery rate, improved displacement conformance, and enhanced durability, allowing it to be effectively used as a sealant for working joints without cracking, meeting durability classification 9030 as per JIS A5758.
Implementation Method 1
by carrying out crosslinking by the formation of a siloxane bond which occurs along with e.g. a hydrolysis reaction of the reactive silicon group caused by e.g. humidity
Implementation Method 2
crosslinking by the formation of a siloxane bond
Implementation Method 3
a tetravalent organotin compound, which enhances curing properties and mechanical performance
Data Source
AI summary
An embodiment of the present invention provides a curable composition which can provide a cured product that (i) has an excellent compression recovery rate, excellent ability to conform to displacement, and excellent durability, and (ii) can be used as a sealant for a working joint of a building. A one-component curable composition for a working joint contains: a polyoxyalkylene-based polymer having a per-molecule average of 1.2 to 5 specific reactive silicon groups; a specific silane compound; and a specific amount of a tetravalent organotin compound.