Treated Particles for Silicone Curing Speed and Rheology Control

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Solution Overview

Problem

Condensation curable silicone compositions containing particulate solids, such as phosphors, often experience slow curing speeds, which is problematic for high-volume manufacturing processes like LED production, and excessive catalyst usage leads to premature curing, preventing adequate encapsulation of ICs and LEDs due to altered rheology.

Innovation Solution

Treated particles with an effective amount of a nitrogen-containing base, such as a superbase, are used to enhance curing speed and control rheology by neutralizing acidic sites on particulate solids, allowing for appropriate flow and encapsulation without premature curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If excessive condensation catalyst is used to increase curing speed, then curing speed is improved, but premature curing occurs which prevents adequate encapsulation of ICs and LEDs

Engineering Contradiction:

Improvecuring speedVSAvoidencapsulation completeness

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent applies preliminary action by treating the particulate solids with a nitrogen-containing base before incorporating them into the condensation curable composition. This pre-treatment neutralizes acidic sites on the particulate surfaces, which would otherwise consume condensation catalyst. By performing this neutralization in advance, the catalyst remains available for its intended function of accelerating silicone curing, thereby achieving fast curing without premature gelation that would prevent proper encapsulation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The nitrogen-containing base acts as an intermediary substance that mediates between the acidic particulate solids and the condensation catalyst. It absorbs the acidic sites on the particulate surfaces, preventing them from interfering with the catalyst's activity. This intermediary treatment allows the catalyst to function effectively at lower concentrations, achieving the desired curing speed while maintaining control over the curing process and ensuring complete encapsulation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If condensation catalyst is used to enhance curing speed, then curing speed is improved, but rheology is altered which prevents adequate flow and encapsulation

Engineering Contradiction:

Improvecuring speedVSAvoidflowability

Core Design Contradiction:

SpeedVSEase of operation

Solution Approach 1:

The nitrogen-containing base treatment is performed in advance on the particulate solids to neutralize acidic sites. This preliminary action prevents these sites from reacting with the condensation catalyst during mixing and curing, thereby maintaining the composition's rheological properties and flowability while still achieving enhanced curing speed through the catalyst.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of acidic sites (which consume catalyst and alter rheology) into a benefit by deliberately treating the particulates with nitrogen-containing base. This treatment transforms the acidic sites into neutralized surfaces that no longer interfere with catalyst activity or rheology, allowing the catalyst to enhance curing speed without the detrimental side effects of premature curing or rheology alteration.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 treated particles significantly increase curing speed while maintaining flowability, ensuring complete encapsulation of ICs and LEDs by optimizing the curing process and maintaining the integrity of the cured product.

Implementation Method 1

Treated particles with an effective amount of a nitrogen-containing base, such as a superbase, are used to enhance curing speed and control rheology by neutralizing acidic sites on particulate solids

Methodology Applied

Scientific EffectNeutralization:

Implementation Method 2

allowing for appropriate flow and encapsulation without premature curing

Methodology Applied

Scientific EffectRheology control:

Implementation Method 3

The treated particles significantly increase curing speed while maintaining flowability, ensuring complete encapsulation of ICs and LEDs by optimizing the curing process

Methodology Applied

Scientific EffectCuring acceleration: Catalysis

Data Source

PatentUS10113111B2Treated fillers and uses thereof

Publication Date: 2018.10.30 DOW SILICONES CORP

AI summary

The various embodiments of the present invention relate to condensation curable silicone compositions comprising: a condensation curable polyorganosiloxane; and treated particles comprising a particulate solid having an effective amount of nitrogen-containing base (e.g., a nitrogen-containing superbase) disposed thereon. Other embodiments of the present invention relate to methods for preparing the aforementioned treated particles; the treated particles themselves; and methods of using the treated particles and compositions of the various embodiments of the present invention.