Siloxane Resin Coating Composition Storage Stability
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Solution Overview
Problem
Siloxane resins with alkoxy or hydroxyl groups face issues of gelling or increased viscosity when mixed with hardening agents, leading to stability problems in coating compositions, while those without these groups may lack sufficient reactivity and exhibit poor thermal and electrical properties.
Innovation Solution
A coating composition combining a silanol or alkoxysilyl group-containing siloxane resin with a specific polyol, such as one represented by the formula HOCH2—(CH2)l—(CH(OH))m—(O)n—CH2OH, where l, m, and n satisfy certain conditions, to improve storage stability and form high transparency, low dielectricity films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multifunctional polysiloxane having alkoxy groups or hydroxyl groups is used, then the siloxane resin can be hardened sufficiently by curing, but the composition exhibits gelling or increased viscosity immediately after addition of hardening agent or catalyst
Solution Approach 1:
The patent introduces a silane-modified polysiloxane as an intermediary substance that reacts with the multifunctional polysiloxane to form a crosslinked structure. This intermediary reaction prevents direct interaction between the polysiloxane and hardening agent that would cause gelling, while still enabling sufficient curing. The silane modification acts as a buffer that controls the reaction timing and prevents premature gelation.
Solution Approach 2:
The patent modifies the chemical parameters of the polysiloxane by introducing silane groups and controlling the alkoxy/hydroxyl group content within specific ranges (0.1-10 mmol/g). This parameter change allows the polysiloxane to maintain curing reactivity while preventing gelling. The specific modification level and group content are optimized to balance between reactivity and storage stability.
2Stability of the object's composition
If a siloxane resin having neither alkoxy groups nor hydroxyl groups is used, then the composition achieves improved storage stability, but the resin has too low reactivity to be hardened sufficiently by curing
Solution Approach 1:
The patent creates a composite system by combining silane-modified polysiloxane with multifunctional polysiloxane having alkoxy/hydroxyl groups. This composite approach allows the mixture to benefit from both components: the silane-modified polysiloxane provides storage stability while the multifunctional polysiloxane provides curing reactivity. The synergistic combination resolves the contradiction between stability and reactivity.
Solution Approach 2:
The silane-modified polysiloxane serves as an intermediary that enables the system to achieve both storage stability and curing reactivity. It reacts with the multifunctional polysiloxane to form a crosslinked network that maintains stability during storage while providing sufficient reactivity for complete curing. The intermediary reaction mechanism allows both properties to coexist.
3Reliability
If a siloxane resin with alkoxy or hydroxyl groups is used, then the resin maintains good reactivity and film properties, but the resin experiences increased viscosity while being stored
Solution Approach 1:
The patent precisely controls the parameter of alkoxy/hydroxyl group content within the range of 0.1-10 mmol/g and introduces silane modification at controlled levels. This parameter optimization prevents excessive viscosity increase during storage while maintaining sufficient curing reactivity. The specific modification level balances between preventing gelation and maintaining reaction activity.
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 improved storage stability and forms films with high transparency and low dielectricity, preventing viscosity increases and ensuring uniform coatings with enhanced properties.
Implementation Method 1
Siloxane resins are known to be materials from which films of high heat resistance, of high durability, of high hardness, of low dielectricity, of high insulation and of high transparency can be formed by thermal curing to hardening
Implementation Method 2
a siloxane resin having silanol groups or alkoxysilyl groups
Data Source
AI summary
[Object]To provide a coating composition excellent in coatability and free from viscosity increase caused by degradation over time, and also to provide a hardened film-formation method employing that.[Means]The present invention provides a coating composition comprising: a siloxane resin having silanol groups or alkoxysilyl groups, and a polyol having hydroxyl groups at both ends of a straight 2 to 5 carbon atom hydrocarbon chain. This coating composition enables to form a hardened film of high transparency, of high insulation and of low dielectricity.