Large-Particle Precipitated Silica for Toothpaste Compatibility
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Solution Overview
Problem
Existing precipitated silicas face challenges in achieving compatibility with ingredients like CPC, BAC, and flavor while maintaining acceptable PCR/RDA values in toothpaste formulations.
Innovation Solution
Developing precipitated silicas with high primary particle sizes greater than 80 nm, specific BET surface areas, total mercury intruded volumes, and oil absorption levels, produced through a controlled acid and alkali metal silicate addition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional precipitated silica with smaller primary particle sizes is used, then higher surface area is achieved, but compatibility with CPC, BAC, and flavor ingredients deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the primary particle size to be greater than 80 nm, which is a specific parameter modification that resolves the contradiction. By adjusting the particle size parameter within this range, the silica achieves both adequate surface area and improved compatibility with CPC, BAC, and flavor ingredients in oral care formulations.
2Reliability
If precipitated silica is used to provide abrasion and cleaning, then PCR/RDA values are achieved, but compatibility with oral care ingredients is compromised
Solution Approach 1:
The patent resolves this contradiction by changing the particle size parameter to greater than 80 nm, which maintains reliable cleaning performance (PCR/RDA values) while simultaneously improving compatibility with oral care ingredients such as CPC, BAC, and flavor components.
3Use of energy by moving object
If smaller primary particle sizes are used, then higher reactivity is achieved, but compatibility with sensitive ingredients like flavor and CPC is reduced
Solution Approach 1:
The patent applies parameter changes by setting the primary particle size greater than 80 nm, which optimizes the reactivity parameter to an appropriate level that maintains sufficient chemical activity while improving compatibility with sensitive ingredients like flavor compounds and CPC.
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 silicas exhibit improved compatibility with CPC, BAC, and flavor, achieving optimal PCR/RDA values, suitable for oral care applications.
Implementation Method 1
Precipitated silica arises when silica is precipitated from this dispersion by the neutralization reaction and the generation of by-product sodium salt (sodium sulfate)
Implementation Method 2
silica is precipitated from this dispersion by the neutralization reaction
Implementation Method 3
The primary particles in the aggregates are covalently bonded to one another by the formation of siloxane bonds
Implementation Method 4
The aggregates themselves can be physically linked to larger agglomerates of up to 100 μm in diameter by the formation of hydrogen bonds between the silanol groups on their surfaces
Data Source
AI summary
The present disclosure relates to precipitated silicas characterized by a primary particle size mean of greater than 80 nm, a BET surface area of 10-40 m²/g, a total mercury intruded volume of 0.75- 2.00 cc/g and an oil absorption of 60-120 cc/100g. The inventive silica is produced by a process comprises (a) continuously feeding an acid and an alkali metal silicate or alkaline earth metal into a liquid medium at a silicate addition rate V1 and a temperature 70-96°C with stirring to form the silica particles, (b) stopping the feed of alkali metal silicate or alkaline earth metal silicate and acid and then increasing the temperature to 90 to 100°C with stirring, (c) adding an alkali metal silicate or alkaline earth metal silicate and an acid with stirring, wherein the silicate addition rate is 1 to 40 % of the silicate addition rate V1 and the pH value of 9.0 to 10.0 is kept constant during the addition of the alkali metal silicate or alkaline earth metal silicate, by adjusting the acid rate, (d) stopping the addition of alkali metal silicate or alkaline earth metal silicate and adding acid with stirring until the pH of 5.0 to 7.0 is reached. The inventive precipitated silica is used in cosmetics, anti-caking free/flow, food, carrier applications, dentifrice and mouthwash.