Precipitated Silica Pore Distribution for Rubber Dispersion
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Solution Overview
Problem
Existing precipitated silicas exhibit poor dispersion in rubber compounds, leading to inadequate abrasion properties, especially in tread compounds.
Innovation Solution
Development of precipitated silicas with specific physico-chemical parameters, including a CTAB surface area ≤ 115 m²/g, DOA oil absorption ≥ 130 ml/100 g, and a pore volume distribution ratio V(d5 - d50) / V(d5 - d100) < 0.66, which improves dispersion and reinforcement in rubber compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precipitated silica with conventional surface area and pore structure is used, then the silica can be easily produced, but the dispersion in rubber compounds is poor
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pore volume distribution ratio V(d5-d50)/V(d5-d100) to be less than 0.66, along with controlling CTAB surface area and other parameters. This specific parameter optimization resolves the contradiction by achieving improved dispersion while maintaining a feasible production process through controlled precipitation conditions.
Solution Approach 2:
The patent utilizes porous materials by specifically engineering the pore volume distribution of the precipitated silica. The controlled pore structure with V(d5-d50)/V(d5-d100) < 0.66 creates optimal surface characteristics that enhance dispersion in rubber compounds while maintaining production feasibility through established precipitation methods.
2Strength
If silica with high surface area is used to improve reinforcement, then the abrasion properties improve, but the dispersion in rubber compounds deteriorates
Solution Approach 1:
The patent applies local quality by creating a specific pore volume distribution within the silica structure (V(d5-d50)/V(d5-d100) < 0.66) that optimizes local surface characteristics. This localized structural optimization allows the silica to achieve both high reinforcement/abrasion resistance and good dispersion, as the specific pore distribution creates favorable interaction zones with the rubber matrix.
Solution Approach 2:
The patent utilizes composite materials by combining silica with specific pore structure characteristics (V(d5-d50)/V(d5-d100) < 0.66) with rubber compounds. This composite approach creates a synergistic effect where the optimized pore structure enhances both reinforcement and dispersion, resolving the contradiction between strength and reliability.
3Strength
If precipitated silica is produced with standard pore volume distribution, then the production process is simple, but the tear propagation behavior is inadequate
Solution Approach 1:
The patent applies parameter changes by optimizing the pore volume distribution ratio V(d5-d50)/V(d5-d100) to be less than 0.66 during precipitation. This parameter optimization improves tear propagation behavior while maintaining relatively simple production processes by controlling precipitation conditions such as pH, temperature, and addition rate.
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 improved silica dispersion results in enhanced reinforcement, better tear propagation behavior, and increased dynamic stiffness, leading to improved handling and wear resistance in rubber products, such as tire treads.
Implementation Method 1
DOA oil absorption ≥ 130 ml/100 g
Implementation Method 2
improved dispersion in rubber compounds
Data Source
AI summary
The invention relates to precipitated silicic acids, with the following physico-chemical parameters CTAB surface ≤ 115 m2/g, DOA ≥ 130 ml / (100 g), RoTap > 300 μm ≥ 86 %, V (d5 - d50) / V (d5 - d100) < 0,66. The precipitated silicic acids are prepared by a) providing an aqueous solution of an organic and/or inorganic salt and/or of an alkali silicate or alkaline earth silicate and/or of an organic and/or inorganic base with a pH ≥ 9, b) simultaneously metering water glass and an acidifier into the feed stock while stirring at 80 - 98 °C for 60 - 120 minutes, c) stopping the addition of water glass and acid only being metered into the feed stock in lower quantities than before to obtain a pH of the mix (measured at 60 °C) of 9.0 - 10.0, d) then stirring the mix for 45 min at up to 200 min at a high temperature > 85 °C, without however adding more reactants, e) acidifying with sulphuric acid to a pH of approximately 3.5 - 4.5 (measured at 60 °C) and f) filtering, drying to a drying loss < 8 % and subsequently granulating the mix. The silicic acids according to the invention can be used in the preparation of rubber blends, in particular for producing tires, cable sheaths, hoses, drive belts, conveyor belts, roll coverings, shoe soles, sealing elements and damping elements.