Silicone Cured Product Processing for Low Volatile Outgassing

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Solution Overview

Problem

Conventional silicone rubber products derived from polyorganosiloxane compositions exhibit volatile component generation at high temperatures, leading to adhesion issues and performance degradation.

Innovation Solution

A method involving the curing of a polyorganosiloxane composition with an alkoxy group having 1 to 3 carbon atoms through hydrosilylation under a closed atmosphere, followed by heating under open atmosphere or reduced pressure to remove residual functional groups and low-molecular compounds, significantly reducing volatile component generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional additional polyorganosiloxane composition is cured by heating, then curing speed is improved, but low-molecular siloxane volatilizes and adheres to circumference causing various problems

Engineering Contradiction:
Improvecuring speedVSAvoidlow-molecular siloxane volatilization
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by performing a pre-curing step at a lower temperature (40-200°C) before the final high-temperature curing. This preliminary curing at controlled conditions allows the polymerization to start without causing excessive volatilization of low-molecular siloxane, while subsequent high-temperature treatment completes the curing process efficiently.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by controlling the curing temperature in stages - first at 40-200°C to initiate curing with minimal volatilization, then at higher temperatures to complete curing. This staged temperature control resolves the contradiction between curing speed and volatilization reduction.

Inventive Principle:
Principle #35Parameter changes

2Loss of substance

If high temperature heat treatment is applied to remove low-molecular siloxane, then removal efficiency is improved, but volatile component is generated when exposed to high temperatures for long time

Engineering Contradiction:
Improvelow-molecular siloxane removalVSAvoidresistance to high temperature exposure
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The patent applies preliminary action by thoroughly removing low-molecular siloxane during the initial curing and heat treatment stages before the product is put into service. This preliminary removal ensures that even when the cured product is later exposed to high temperatures (80-150°C) for long periods, there is minimal low-molecular siloxane left to volatilize, thus maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent ensures continuity of useful action by implementing a comprehensive curing and heat treatment process that continuously acts to remove low-molecular siloxane from the system. This continuous removal action during manufacturing prevents subsequent volatilization issues during long-term high-temperature exposure.

Inventive Principle:
Principle #20Continuity of useful action

3Ease of manufacture

If conventional curing method is used, then manufacturing process is simple, but volatile component generation occurs at elevated temperatures

Engineering Contradiction:
Improvecuring process simplicityVSAvoidvolatile component generation
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent applies segmentation by dividing the curing process into distinct stages: an initial curing step at 40-200°C, followed by a heat treatment step at higher temperatures. This segmented approach maintains relative manufacturing simplicity while effectively preventing volatile component generation during long-term high-temperature exposure.

Inventive Principle:
Principle #1Segmentation

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 effectively minimizes volatile component generation in silicone cured products, even at elevated temperatures, thereby preventing adhesion and maintaining product integrity.

Implementation Method 1

a curing step of curing an additional polyorganosiloxane composition by hydrosilylation reaction

Methodology Applied
Scientific EffectHydrosilylation reaction: Chemical Bonding

Implementation Method 2

a heating step of heating the primary cured product under open atmosphere or reduced pressure

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

heating the primary cured product under open atmosphere or reduced pressure at a temperature of not lower than 60° C. nor higher than 160° C.

Methodology Applied
Scientific EffectDistillation: Distillation

Data Source

PatentUS12065567B2Method of manufacturing silicone cured product, silicone cured product and optical member
Publication Date: 2024.08.20 MOMENTIVE PERFORMANCE MATERIALS JAPAN LLC

AI summary

To provide a method of manufacturing a silicone cured product and a silicone cured product which allow generation of a volatile component to be reduced significantly even being exposed to high temperatures of room temperature or more for a long time. A method of manufacturing a silicone cured product includes: curing an additional polyorganosiloxane composition by hydrosilylation reaction under closed atmosphere at a temperature of 40° C. or more and 200° C. or less to obtain a primary cured product; and heating the primary cured product under open atmosphere or reduced pressure at a temperature of 60° C. or more and 160° C. or less, and a silicone cured product in which when heated at 150° C. for 16 hours, a total generation amount of an alcohol having 1 to 3 carbon atoms and an oxide thereof, and an alkyl group-containing silane compound having 1 to 3 carbon atoms is 10 ppm or less.