Two-Stage Catalyst System for Low-Temperature Organopolysiloxane Curing

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Solution Overview

Problem

Existing organopolysiloxane compositions face challenges in achieving quick curing at low temperatures while maintaining sufficient pot life and mechanical strength, often resulting in incomplete curing and discoloration issues when using high-energy-radiation-activated catalysts or heat-activated catalysts.

Innovation Solution

A method involving a two-stage hydrosilylation reaction using a composition with a first catalyst active at low temperatures and a second catalyst activated by high-energy radiation, allowing for low-temperature curing without heating, which includes components (A) through (D): an organopolysiloxane with specific average composition formulas, a hydrosilylation reaction catalyst active without radiation, and a radiation-activated catalyst.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If high-energy-radiation-activated catalyst is used to enable low-temperature curing, then curing temperature is reduced, but curing completeness and mechanical strength deteriorate

Engineering Contradiction:
Improvecuring temperatureVSAvoidmechanical strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent divides the catalyst system into two distinct segments: a first catalyst (platinum complex) that operates at low temperatures to initiate curing, and a second catalyst (radical-type catalyst) that operates at high temperatures to complete the curing process. This segmentation allows each catalyst to perform its function optimally without interfering with the other, resolving the contradiction between low-temperature operation and complete curing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first catalyst performs preliminary curing action at low temperatures before the second catalyst completes the process at high temperatures. This preliminary action ensures that the base structure is formed at low temperature while the subsequent high-temperature treatment completes the curing to achieve full mechanical strength.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If heat-activated catalyst is used to achieve quick curing, then curing time is reduced, but substrate temperature requirement increases

Engineering Contradiction:
Improvecuring timeVSAvoidsubstrate temperature
Core Design Contradiction:
Loss of timeVSTemperature

Solution Approach 1:

The curing process is segmented into two stages with different temperature requirements and catalysts. The first stage uses a platinum catalyst at low temperatures for initial curing, and the second stage uses a radical catalyst at high temperatures for complete curing. This segmentation allows the process to achieve quick curing without requiring the entire process to occur at high temperatures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of catalyst type at different stages of the curing process. By switching from a platinum-based catalyst at low temperature to a radical-based catalyst at high temperature, the system optimizes both curing speed and temperature requirements for each stage.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If catalyst amount is increased to achieve complete curing, then curing completeness is improved, but discoloration occurs

Engineering Contradiction:
Improvecuring completenessVSAvoiddiscoloration
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the catalyst function between two different catalysts with different mechanisms. The first catalyst (platinum) operates at low concentrations for initial curing without causing discoloration, while the second catalyst (radical-type) operates at high temperatures to complete curing. This segmentation allows complete curing to be achieved without the discoloration problems associated with high concentrations of a single catalyst.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first catalyst acts as an intermediary that initiates the curing process at low temperature and low concentration, avoiding discoloration. Then the second catalyst serves as an intermediary to complete the curing at high temperature, ensuring completeness without the discoloration issues that would result from using high concentrations of a single catalyst throughout.

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

This approach enables efficient, rapid curing at low temperatures with sufficient pot life and high mechanical strength, preventing discoloration and incomplete curing, making it suitable for applications in laminates and optical devices.

Implementation Method 1

a step of performing, without irradiating with high-energy radiation, a hydrosilylation reaction upon a composition containing components (A) through (D) to obtain a thickened material

Methodology Applied
Scientific EffectHydrosilylation reaction: Chemical Bonding

Implementation Method 2

a step of irradiating the thickened material or thermoplastic material obtained in step (i) with high-energy radiation

Methodology Applied
Scientific EffectHigh-energy radiation activation: Photopolymerisation

Data Source

PatentUS11591440B2Method for producing organopolysiloxane cured product, organopolysiloxane cured product, layered product, and optical part
Publication Date: 2023.02.28 DOW TORAY CO LTD

AI summary

Provided is a cured product using a composition that is capable of quick curing at low temperatures while having sufficient pot life at room temperature, a method of producing the same, a laminate, and an optical device. A method of producing an organopolysiloxane cured product is provided. The method includes: (i) performing, without irradiating with high-energy radiation, a hydrosilylation reaction upon a composition containing a first hydrosilylation reaction catalyst that exhibits activity in the composition and a second hydrosilylation reaction catalyst that does not exhibit activity when not irradiated with high-energy radiation, but exhibits activity in the composition when irradiated with high-energy radiation, to obtain a thickened material that is fluid at room temperature or a thermoplastic material that is non-fluid at room temperature but exhibits fluidity at 100° C.; and (ii) irradiating the thickened material or thermoplastic material obtained in step (i) with high-energy radiation to obtain a cured product.