Silicone Elastomer Composition Hydrosilylation Stoichiometry Control
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Solution Overview
Problem
The production of high molecular weight, highly branched pituitous silicone fluids is challenging due to sensitivity to stoichiometry in the reaction process, leading to inconsistent yields and difficulty in adding large side chains, which affects their usability in personal care products.
Innovation Solution
A silicone elastomer composition is developed using a hydrosilylation reaction product of linear organopolysiloxanes, which is less sensitive to stoichiometry and allows for easier addition of large side chains, incorporating a carrier fluid to enhance sensory characteristics and durability on the skin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly branched organopolysiloxanes are produced using conventional processes, then the fluids exhibit pituitous behavior and entanglements under shear stress, but the production is very sensitive to stoichiometry leading to inconsistent yields
Solution Approach 1:
The patent changes the structural parameters of the reactants from highly branched/cyclic to linear organopolysiloxanes. This parameter change fundamentally alters the reaction characteristics, making the hydrosilylation process less sensitive to stoichiometric variations and enabling consistent production of pituitous silicone fluids with predictable molecular weights and architectures.
Solution Approach 2:
Instead of attempting to improve the conventional highly branched synthesis process, the patent inverts the approach by using linear organopolysiloxanes as starting materials. This inversion of the conventional wisdom leads to a more robust and controllable reaction process that is less sensitive to stoichiometric imbalances.
2Adaptability or versatility
If highly branched organopolysiloxanes are used to achieve pituitous behavior, then the fluids show interesting rheological properties, but large side chains are difficult to add due to steric hindrance
Solution Approach 1:
The patent inverts the conventional approach by starting with linear organopolysiloxanes instead of highly branched structures. This inversion eliminates the steric hindrance problem that prevents addition of large side chains, while still enabling the formation of pituitous behavior through controlled hydrosilylation and subsequent branching during curing or further reaction.
Solution Approach 2:
The patent segments the synthesis process into distinct stages: first forming the linear hydrosilylation product with desired side chains attached to the linear backbone, then allowing controlled branching to develop pituitous behavior. This segmentation enables addition of large side chains without the steric constraints of simultaneous branching.
3Reliability
If conventional pituitous silicone fluids are produced, then the fluids exhibit Weissenberg effect and climbing rod behavior, but the production process is complex and difficult to control
Solution Approach 1:
The patent changes key parameters including reactant structure (linear vs. highly branched), reaction type (hydrosilylation), and molecular weight range. These parameter changes simplify the reaction process by reducing sensitivity to stoichiometry and enabling more predictable product properties with consistent pituitous behavior.
Solution Approach 2:
The patent uses linear organopolysiloxanes as intermediaries that first undergo hydrosilylation to attach side chains, then subsequently form the highly branched pituitous structure. This intermediary step provides better control over the final product properties and simplifies the overall process by breaking it into more manageable stages.
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 provides consistent and customizable sensory characteristics, improved skin coverage, and longer-lasting physical properties, with the ability to form a pseudo-film on skin, enhancing the usability of pituitous silicone fluids in personal care applications.
Implementation Method 1
The pituitous silicone fluid includes a hydrosilylation reaction product of a first linear organopolysiloxane and a second linear organopolysiloxane
Implementation Method 2
The phenomenon of a viscoelastic liquid climbing a rotating rod, known as the Weissenberg effect, has been observed in polymer solutions, and in pituitous silicone fluids
Implementation Method 3
The addition of the silicone elastomer allows the physical properties and sensory characteristics of the composition to be customized
Data Source
AI summary
A silicone elastomer composition (“composition”) has customizable sensory characteristics. The composition includes a pituitous silicone fluid that includes a hydrosilylation reaction product and a carrier fluid. The hydrosilylation reaction product generally includes alkenyl or Si—H functionality. The hydrosilylation reaction product is the reaction product of a first linear organopolysiloxane including (R1R2R3SiO—1/2) and (R4R5Si)2/2) units, and a second linear organopolysiloxane including (R6R7R8SiO—1/2) and (R9R10SiO2/2) units. Each of R1-R10 is independently a hydrocarbon group so long as at least one of R1-R5 is an alkenyl group and at least one of R6-R10 is a hydrogen atom. The first linear organopolysiloxane has a DP of from 100 to 15,000. The second linear organopolysiloxane has a DP of from 4 to 1,000. The composition also includes a silicone elastomer different from the hydrosilylation reaction product. Personal care compositions can include the composition.