Photosensitive Composition for Stereolithography Resolution

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Solution Overview

Problem

Current photolithographic rapid prototyping technologies, such as stereolithography, face limitations in fabrication rate, resolution, and quality due to high cure speeds leading to issues like layer bleeding, distortion, and brittleness in 3D printed articles, which are exacerbated by the need for high photoinitiator contents and multiple light wavelengths for control.

Innovation Solution

A photosensitive composition comprising a photoinitiator, photoinhibitor, photosensitizer, and chain transfer agent, allowing for improved resolution and cure depth without increasing gelation exposure energy, using a single light source by optimizing absorption maxima of the components within the 300-1000 nm range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high cure speed is used to improve productivity, then fabrication rate is improved, but resolution deteriorates due to layer bleeding and poor quality

Engineering Contradiction:

Improvefabrication rateVSAvoidresolution

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical parameters of the photosensitive composition by introducing a photoinhibitor component with specific absorption characteristics. This modifies the cure kinetics to achieve a balance between cure speed and resolution, allowing fast fabrication while preventing layer bleeding through controlled polymerization inhibition.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite photosensitive system combining photoinitiator, photoinhibitor, photosensitizer, and chain transfer agent components. This composite approach enables simultaneous control of cure rate and resolution by leveraging the complementary properties of each component working together.

Inventive Principle:

Principle #40Composite materials

2Productivity

If high photoinitiator content is used to increase cure speed, then productivity is improved, but gelation exposure energy increases and cure depth decreases

Engineering Contradiction:

Improvecure speedVSAvoidgelation exposure energy

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent introduces a photosensitizer as an intermediary that mediates between the photoinitiator and the monomer. The photosensitizer absorbs light energy and transfers it to the monomer, enabling efficient curing at lower photoinitiator concentrations and reducing the energy required for gelation while maintaining adequate cure depth.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the absorption spectrum parameters by selecting photoinhibitor and photosensitizer compounds with specific absorption maxima that optimize energy utilization. This parameter optimization allows efficient curing with reduced exposure energy and maintained cure depth.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If multiple light wavelengths are used to control polymerization regions, then manufacturing precision is improved, but device complexity increases and time is consumed

Engineering Contradiction:

Improvecontrol of polymerizationVSAvoidnumber of light wavelengths

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the polymerization control function into distinct chemical components (photoinitiator for initiation, photoinhibitor for inhibition, photosensitizer for energy transfer) that can be activated by a single wavelength. This chemical segmentation replaces the need for multiple light wavelengths, maintaining precision while reducing device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent substitutes the mechanical/optical system of multiple light wavelengths with a chemical system of specialized compounds. The photoinhibitor and photosensitizer components work together to provide spatial and temporal control of polymerization through their photochemical interactions, eliminating the need for complex multi-wavelength lighting systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 composition enables the production of high-quality 3D printed articles with improved resolution and reduced manufacturing process impacts on gelation exposure energy and cure depth, using a single light source for efficient curing.

Implementation Method 1

a photoinitiator component; a photoinhibitor component; a photosensitizer component; and a chain transfer agent component

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

concurrent photoinitiation and photoinhibition using two wavelengths of light provides improved control of polymerization

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

a photosensitizer component

Methodology Applied

Scientific EffectPhotosensitization: Photosynthesis

Data Source

PatentUS20240377736A1Photosensitive composition

Publication Date: 2024.11.14 ARKEMA FRANCE SA

AI summary

The present invention relates to a photosensitive composition comprising a photoinitiator component, a photoinhibitor component, a photosensitizer component, and a chain transfer agent component. The present invention further relates to a curable composition comprising an ethylenically unsaturated compound and the photosensitive composition and a method for producing a cured product from the curable composition.