Thiol-ene Silicone Additive Fabrication Oxygen Inhibition

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Solution Overview

Problem

Existing additive fabrication techniques, such as SLA, face challenges in producing well-cured silicone parts due to issues like oxygen inhibition, viscosity problems, and poor adhesion between layers.

Innovation Solution

The use of a photocurable silicone composition comprising a mercapto-derivatized polysiloxane with two or more functional groups and an alkenyl-derivatized polysiloxane, along with a photoinitiator, in an additive fabrication process that involves irradiation with an energy source like a UV laser to form crosslinked layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional SLA techniques are used to produce silicone parts, then the fabrication process can be implemented, but the parts suffer from poor curing due to oxygen inhibition and viscosity problems

Engineering Contradiction:

Improvecuring qualityVSAvoidoxygen inhibition

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies inert atmosphere by formulating the silicone composition with specific ratios of mercapto-derivatized polysiloxane to alkenyl-derivatized polysiloxane (greater than 1:99, greater than 5:95, greater than 10:90, greater than 20:80, or greater than 30:70 by weight) to create an oxygen-inhibited environment that prevents oxygen from interfering with the photopolymerization process, thereby achieving reliable curing without oxygen inhibition

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Reliability

If conventional silicone-based SLA printing is used, then fabrication is possible, but the parts exhibit poor adhesion between layers

Engineering Contradiction:

Improvelayer adhesionVSAvoidinterlayer adhesion

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies parameter changes by optimizing the molecular weight and functional group content of the polysiloxane components, specifically using mercapto-derivatized polysiloxane with two or more functional groups and controlling the ratio between mercapto- and alkenyl-derivatized polysiloxane to achieve proper adhesion between layers through modified chemical parameters

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If traditional photocurable silicone composition is used, then the material can be processed, but the resulting objects have poor mechanical properties including reduced tear strength and elongation

Engineering Contradiction:

ImproveprocessabilityVSAvoidtear strength and elongation

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent applies composite materials by combining mercapto-derivatized polysiloxane with two or more functional groups and alkenyl-derivatized polysiloxane in specific ratios (greater than 1:99, greater than 5:95, greater than 10:90, greater than 20:80, or greater than 30:70 by weight) to create a composite photocurable composition that achieves both processability and improved mechanical properties including tear strength and elongation

Inventive Principle:

Principle #40Composite materials

4Ease of manufacture

If conventional photocurable silicone composition is used, then fabrication can proceed, but the objects exhibit increased tackiness

Engineering Contradiction:

Improvefabrication capabilityVSAvoidtackiness

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition parameters of the photocurable silicone material, specifically controlling the ratio of mercapto-derivatized polysiloxane to alkenyl-derivatized polysiloxane and adjusting the functional group content to reduce tackiness while maintaining fabrication capability

Inventive Principle:

Principle #35Parameter changes

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 the production of well-defined, properly cured silicone objects with improved tear strength, elongation, and reduced tackiness, overcoming the limitations of previous silicone-based SLA printing.

Implementation Method 1

irradiating a layer of the photocurable silicone composition with an energy source to form an at least partially cured layer

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

The photocurable silicone composition can include a mercapto-derivatized polysiloxane having two or more functional groups, an alkenyl-derivatized polysiloxane, and a photo-initiator

Methodology Applied

Scientific EffectPhoto-initiator: Photopolymerisation

Implementation Method 3

a photocured silicone composition including a crosslinked alkenyl-derivatized polysiloxane and a mercapto-derivatized polysiloxane having two or more functional groups

Methodology Applied

Scientific EffectThiol-ene crosslinking: Chemical Bonding

Data Source

PatentUS12275847B2Thiol-ene silicone additive fabrication

Publication Date: 2025.04.15 FORMLABS INC

AI summary

Methods and compositions for additive manufacturing of silicone parts are provided. The methods can use SLA printing techniques to print silicone parts that exhibit excellent hardness, tear strength and elongation at break. The parts can be produced by using low dosages of radiation. In various embodiments, the silicone compositions include a mercapto-derivatized polysiloxane having two or more functional groups, an alkenyl-derivatized polysiloxane, and a photo-initiator.