Photocurable Organopolysiloxane Composition with Titanium Complex
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Solution Overview
Problem
Existing photocurable organopolysiloxane compositions face issues such as odor problems, corrosion on metal, poor curability, and limited applications due to the use of mercapto group-containing polysiloxanes and acrylic group-containing polysiloxanes, which require special synthetic routes and result in products with poor tensile strength and storage stability.
Innovation Solution
Incorporating a complex compound composed of titanium-(meth)acrylate-trialkoxide and β-diketone into a photocurable organopolysiloxane composition enhances curability upon UV irradiation, eliminating the need for photofunctional organopolysiloxanes and enabling the production of cured products with excellent rubbery characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vinyl group-containing polysiloxane and a mercapto group-containing polysiloxane are used for photocurable composition, then the composition can cure through photo-radical addition reaction, but the composition produces odor and causes corrosion on metal
Solution Approach 1:
The patent removes the problematic mercapto group-containing polysiloxane from the composition and replaces it with a silane-modified polysiloxane that contains hydrolyzable groups. This extraction of the harmful component eliminates odor and corrosion issues while maintaining the desired photocurable properties through the silane-modified polysiloxane's hydrolyzable groups.
Solution Approach 2:
The patent changes the chemical groups present in the polysiloxane from vinyl and mercapto groups to silane-modified groups with hydrolyzable functionality. This parameter change in the chemical composition allows the material to maintain curability through hydrolysis and condensation reactions while eliminating the harmful odor and corrosion characteristics of the original mercapto group-containing polysiloxane.
2Stability of the object's composition
If an acrylic group-containing polysiloxane with high molecular weight is used for photocurable composition, then the composition can form rubbery elastic product, but the amount of terminal acrylic group decreases leading to poor curability
Solution Approach 1:
The patent changes the approach by using silane-modified polysiloxane with hydrolyzable groups instead of relying on terminal acrylic groups. This parameter change allows the polysiloxane to maintain both high molecular weight for rubbery properties and sufficient reactivity for curability through hydrolysis and condensation of the silane-modified groups.
Solution Approach 2:
The silane-modified groups act as intermediaries that facilitate the curing process. The hydrolyzable groups on the silane-modified polysiloxane serve as reactive sites that enable crosslinking through hydrolysis and condensation reactions, providing both the rubbery elastic properties and sufficient curability without requiring high concentrations of terminal acrylic groups.
3Reliability
If air is present during composition storage, then the surface cures very little due to inhibitive action, but the composition requires practical usability
Solution Approach 1:
The patent changes the chemical mechanism from one sensitive to air inhibition to one based on hydrolysis and condensation of silane-modified groups. This parameter change in the curing mechanism makes the composition less sensitive to air presence, allowing adequate surface curing while maintaining storage stability.
4Productivity
If mercapto group-containing polysiloxane and acrylic group-containing polysiloxane are used, then the composition can cure, but special synthetic routes are required resulting in high cost and legal regulations
Solution Approach 1:
The patent uses readily available silane-modified polysiloxane with hydrolyzable groups that can be incorporated into the composition through simple mixing, eliminating the need for complex synthetic routes to produce specialized mercapto or acrylic group-containing polysiloxanes. This approach reduces manufacturing complexity and cost while maintaining curability.
Solution Approach 2:
The silane-modified polysiloxane with hydrolyzable groups serves multiple functions: it provides the necessary reactivity for curing through hydrolysis and condensation, eliminates the need for special synthetic routes, and avoids the harmful properties of alternative compounds. This universal component simplifies manufacturing while achieving the desired curability.
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 resulting photocurable organopolysiloxane compositions exhibit improved curability, reduced cure shrinkage, and enhanced mechanical strength, making them suitable for applications as sealing agents, adhesives, and coating materials in micro parts and precision molding.
Implementation Method 1
a photocurable organopolysiloxane composition comprising: (A) 100 parts by weight of a diorganopolysiloxane having at least two silicon atoms having a hydroxyl group and/or hydrolyzable group attached thereto in one molecule; and (B) 0.1 to 30 parts by weight of a complex compound composed of titanium-(meth)acrylate-trialkoxide and β-diketone
Data Source
AI summary
Disclosed is a photocurable organopolysiloxane composition including (A) 100 parts by weight of diorganopolysiloxane having at least two silicon atoms having a hydroxyl group and/or hydrolyzable group attached thereto in one molecule; and (B) 0.1 to 30 parts by weight of a complex compound composed of titanium(meth)acrylate-trialkoxide and β-diketone. It will find use as a sealing agent, adhesive, coating material. It is particularly suitable for micro pars and precision molding on account of its good curability and very little cure shrinkage.