Organopolysiloxane Composition for Low-Modulus Transducer Dielectric Layers
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Solution Overview
Problem
Existing curable organopolysiloxane compositions for transducers do not adequately address the need for low storage modulus and low loss tangent properties, particularly in dielectric layers, which are crucial for favorable reversion characteristics after deformation by external stresses.
Innovation Solution
A curable organopolysiloxane composition comprising straight chain or branched chain organopolysiloxanes with a weight-average molecular weight less than 8.0×10^4, specific SiH/Vi ratio, and a hydrosilylation reaction catalyst, along with optional reinforcing fillers and adhesion promoters, to achieve a low storage modulus and low loss tangent across a broad frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional curable organopolysiloxane compositions are used, then mechanical strength and dielectric breakdown strength are achieved, but storage modulus remains high and loss tangent is not sufficiently low
Solution Approach 1:
The patent applies parameter changes by precisely controlling the weight-average molecular weight of the organopolysiloxane (Mw < 8.0×10^4) and the crosslink density parameter (Mw(a)/px1 between 1,000-8,000). These parameter adjustments optimize the balance between mechanical strength and viscoelastic properties, achieving low storage modulus and low loss tangent while maintaining adequate mechanical strength and dielectric breakdown strength.
Solution Approach 2:
The patent uses composite materials by combining organopolysiloxane with specific additives including adhesion promoters (γ-methacryloxypropyl)trimethoxysilane), reinforcing fillers, and curing catalysts. This composite approach allows the dielectric layer to achieve multiple properties simultaneously: low storage modulus, low loss tangent, good adhesion, and sufficient mechanical strength.
2Strength
If crosslink density is increased to improve mechanical strength, then tensile strength improves, but storage modulus increases and reversion characteristics deteriorate
Solution Approach 1:
The patent resolves this contradiction through parameter changes by controlling the crosslink density within an optimal range. The parameter Mw(a)/px1 is maintained between 1,000-8,000, where px1 represents crosslink density. This controlled crosslinking achieves sufficient tensile strength (≥2.0 MPa) while keeping storage modulus low and loss tangent ≤0.35, ensuring good reversion characteristics after deformation.
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 yields a cured product with excellent viscoelastic properties, suitable for use as a dielectric layer in transducers, demonstrating favorable reversion characteristics and low storage modulus, enhancing durability and practical displacement.
Implementation Method 1
a curable organopolysiloxane composition comprising straight chain or branched chain organopolysiloxanes with a weight-average molecular weight less than 8.0×10^4, specific SiH/Vi ratio, and a hydrosilylation reaction catalyst
Data Source
AI summary
[Problem] To provide a curable organopolysiloxane composition that yields a organopolysiloxane cured product having viscoelastic properties (particularly, reversion characteristics after deformation due to external stress) that are particularly suitable for use as a dielectric layer or a transducer, and a method of use thereof. [Resolution Means] A curable organopolysiloxane composition for transducers, containing, (a) a chain organopolysiloxane or mixture thereof having a weight-average molecular weight (Mw(a)) of less than 8.0×104, and (b1) a crosslinking agent, (b2) a chain length extender, and (c) a hydrosilylation reaction catalyst, wherein the molar quantity of Si-H (Hb1, Hb2) in component (b1) and component (b2) and the molar quantity of curable reactive groups (Vi) in component (a), satisfy the following relationship: px1 ={ Hb1/ Hb2}/{(Hb1+ Hb2)/Vi} and wherein the obtained by dividing Mw(a) by the value of px1 (=Mw(a)/px1) is in a range of 1,000 to 8,000.