Millable Silicone Rubber Composition for High Plasticity at Low Hardness
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Solution Overview
Problem
Existing millable silicone rubber compounds face issues with low plasticity and processability due to improper use of surface treatment agents, leading to defects such as deformation and stickiness, while adding more agents can cause reverse plasticization or increased hardness.
Innovation Solution
A millable silicone rubber compound comprising organopolysiloxane raw rubber, reinforcing silica, partial hydrolysate of organoalkoxysilane, and a condensation reaction catalyst, which enhances plasticity and processability without increasing hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a large amount of surface treatment agent is used, then dispersion of reinforcing filler is improved, but plasticity of the silicone rubber compound decreases
Solution Approach 1:
The invention changes the chemical parameters of the surface treatment agent by specifying particular organosilane compounds with controlled hydrolysis degrees. By controlling the hydrolysis degree to be 20-80% and selecting specific R groups, the invention achieves optimal balance between dispersion and plasticity without requiring excessive amounts of additive.
Solution Approach 2:
The invention creates a composite surface treatment system combining multiple organosilane compounds with different R groups (methyl, ethyl, propyl, butyl) in specific ratio ranges. This composite approach synergistically improves dispersion while maintaining plasticity better than single compounds.
2Stability of the object's composition
If a large amount of surface treatment agent is used, then dispersion of reinforcing filler is improved, but processability deteriorates due to stickiness
Solution Approach 1:
The invention controls the stickiness parameter by limiting the total amount of surface treatment agent to 1-10 parts by mass and by controlling the hydrolysis degree to 20-80%. This parameter control prevents excessive stickiness while maintaining adequate dispersion.
Solution Approach 2:
The invention applies different R groups (methyl, ethyl, propyl, butyl) in specific ratio ranges to create local chemical environment variations on the silica surface, optimizing both dispersion and surface properties to reduce stickiness.
3Ease of operation
If a small amount of surface treatment agent is used, then plasticity is maintained, but reverse plasticization occurs due to insufficient dispersion
Solution Approach 1:
The invention changes the effectiveness parameter of the surface treatment by controlling the hydrolysis degree to 20-80% and selecting specific organosilane compounds. This ensures adequate dispersion even at low additive amounts (1-10 parts by mass), preventing reverse plasticization.
4Ease of operation
If heating treatment is performed to reduce reverse plasticization, then plasticity improves, but production cost increases
Solution Approach 1:
The invention performs preliminary surface treatment of the reinforcing filler with controlled hydrolysis organosilane compounds before compounding. This preliminary action ensures optimal dispersion and plasticity without requiring subsequent expensive heating treatment, thereby reducing production costs.
5Ease of operation
If condensation reaction catalyst is added to increase plasticity, then plasticity improves, but stability of plasticity decreases
Solution Approach 1:
The invention changes the chemical composition parameters by selecting specific organosilane compounds with controlled hydrolysis degrees and R group ratios. This compositional control achieves stable plasticity without requiring condensation catalysts, avoiding the instability problem.
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 compound achieves high plasticity and improved processability, reducing defects and maintaining mechanical strength, even at low hardness levels.
Implementation Method 1
plasticity can be increased by adding a condensation reaction catalyst of an organic metal compound selected from an organic titanium compound, an organic zirconium compound, and an organic aluminum compound, and performing heat treatment for condensation of silanol
Implementation Method 2
0.1 to 20 parts by mass of a partial hydrolysate of organoalkoxysilane represented by the following general formula (1)
Data Source
AI summary
A millable silicone rubber compound including: (A) organopolysiloxane raw rubber; (B) reinforcing silica having a specific surface area of 50 to 450 m2/g; (C) a partial hydrolysate of organoalkoxysilane represented by the following general formula (1); and (D) one or more kinds of condensation reaction catalysts selected from the following (D1) to (D3): (D1) an amine compound having a boiling point of 30 to 60° C. at 1013 hPa, the amine compound being in a liquid state at 25° C., (D2) hexaorganodisilazane represented by the following general formula (2), and (D3) ammonia water at 1.0 to 30.0 mass %. Thus, the invention provides: a millable silicone rubber compound that enable to achieve high plasticity regardless of relatively low hardness of the millable silicone rubber compound, a millable silicone rubber composition, and a method for producing a millable silicone rubber composition.