Silica Sol Phosphate Surface Modification Stability

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Solution Overview

Problem

Silica-based sols used in papermaking face challenges with high surface area particles leading to decreased long-term stability, while maintaining efficiency as drainage and retention aids.

Innovation Solution

Introducing phosphate groups on the surface of silica particles in the sol by reacting with modifiers like metaphosphoric acid or polyphosphoric acid, maintaining a specific surface area below 115 m²/g, which improves stability and efficiency without increasing surface area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If silica-based particles with high specific surface area are used, then the efficiency as drainage and retention aid is improved, but the long-term stability of the sol decreases

Engineering Contradiction:
Improveefficiency as drainage and retention aidVSAvoidlong-term stability of the sol
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition of the silica particle surface through phosphate group introduction. This chemical modification alters the surface properties without changing the physical surface area, thereby improving stability while maintaining efficiency. The phosphate groups change the surface chemistry to reduce aggregation and improve colloidal stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material by combining silica particles with phosphate groups on their surface. This composite structure maintains the high surface area benefits of silica while adding the stability-enhancing properties of phosphate modification. The composite approach allows both high efficiency and long-term stability to coexist.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the specific surface area of silica-based particles is increased, then the efficiency is improved, but the storage stability over prolonged time deteriorates

Engineering Contradiction:
ImproveefficiencyVSAvoidstorage stability over prolonged time
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical parameters of the particle surface by introducing phosphate groups. This chemical parameter change improves storage stability without requiring an increase in surface area. The phosphate modification alters the surface energy and interaction characteristics, preventing aggregation during prolonged storage.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If phosphate groups are introduced on the surface of silica particles, then the storage stability is improved, but the complexity of the production process increases

Engineering Contradiction:
Improvestorage stabilityVSAvoidcomplexity of the production process
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent uses an intermediary approach by employing a multi-step process with controlled pH adjustment. The phosphate group introduction is facilitated through a systematic sequence of operations involving modifier addition, pH control, and stabilization. This intermediary process management simplifies the overall complexity by breaking down the modification process into controllable stages.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method produces a silica-based sol with enhanced retention and drainage aid efficiency while ensuring long-term storage stability, allowing for lower usage amounts and improved performance in papermaking processes.

Implementation Method 1

Introducing phosphate groups on the surface of silica particles in the sol by reacting with modifiers like metaphosphoric acid or polyphosphoric acid

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP2522626B1Method of producing silica-based sol, silica-based sol and its use
Publication Date: 2016.07.20 KEMIRA OY

AI summary

The invention relates to a method of producing a silica-based sol. The method comprises obtaining silica-based sol comprising silica particles, and introducing phosphate groups on the surface of the silica particles. The invention relates also to a silica-based sol comprising silica particles, which have an average particle size below 50 nm. SiO2 content of the silica based sol is at least 5 weight-% and phosphorous content at least 0.0055 weight-%.