Optical Stereolithography Composition for Layer Adhesion and Warping Control
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Solution Overview
Problem
Commercial stereolithographic objects produced by stereolithography often face issues with strength, warping, and increased production time due to inadequate adhesion of thin cured film layers and insufficient heat resistance, which affects their mechanical properties and efficiency in applications involving force and heat.
Innovation Solution
A composition for optical stereolithography comprising radical polymerizable compounds such as dioxane (meth)acrylate, bifunctional polyester-based urethane (meth)acrylate, and bifunctional polyether-based urethane (meth)acrylate, along with a photopolymerization initiator and sensitizer, which are formulated to provide rapid curing and enhanced mechanical strength, adhesion, and heat resistance when subjected to ultraviolet irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thin cured film layers are stacked to form stereolithographic objects, then complex shapes can be fabricated without molds, but the strength of the object is affected due to poor adhesion between layers
Solution Approach 1:
The patent modifies the chemical composition parameters of the photocurable resin by incorporating specific silane-modified polyether polyol components and controlling the ratio of monofunctional to polyfunctional acrylate groups. This chemical parameter optimization enhances the adhesion between stacked cured film layers, thereby improving the overall strength of the stereolithographic object while maintaining the ability to fabricate complex shapes
Solution Approach 2:
The patent creates a composite photocurable resin system combining silane-modified polyether polyol, monofunctional acrylate, and polyfunctional acrylate components. This composite material approach leverages the synergistic effects of different chemical components to achieve both good layer adhesion and high mechanical strength in the final stereolithographic object
2Productivity
If conventional photocurable resins are used, then stereolithographic objects can be produced, but they warp and are caught by ultraviolet laser scanner during production
Solution Approach 1:
The patent optimizes the molecular weight and functional group composition parameters of the polyether polyol component, specifically using silane-modified polyether polyol with controlled molecular weight and silane content. This parameter optimization reduces differential shrinkage during curing, preventing warping and ensuring stable production of stereolithographic objects without interference from the ultraviolet laser scanner
3Temperature
If multiple ultraviolet irradiation treatments and heat treatments are performed to improve heat resistance, then heat resistance is enhanced, but the number of steps increases and work efficiency decreases
Solution Approach 1:
The patent extracts and eliminates the need for separate post-curing heat treatment steps by incorporating heat-resistant functional groups directly into the photocurable resin composition. The silane-modified polyether polyol and acrylate components provide inherent heat resistance that is achieved through the single photocuring step, removing the need for additional ultraviolet irradiation and heat treatment processes
Solution Approach 2:
The patent merges the heat resistance functionality into the base photocurable resin composition itself, rather than requiring separate post-treatment steps. The silane-modified polyether polyol and acrylate components provide both photocurability and heat resistance in a single material system, allowing simultaneous achievement of both properties in one curing process
4Ease of manufacture
If conventional photocurable resins are used, then stereolithographic objects can be produced, but they lack sufficient mechanical characteristics such as toughness and durability
Solution Approach 1:
The patent develops a composite photocurable resin system combining silane-modified polyether polyol with specific ratios of monofunctional and polyfunctional acrylates. This composite formulation provides enhanced mechanical characteristics including toughness and durability through the synergistic interaction of different chemical components, while maintaining ease of manufacture through direct photocuring without complex processing steps
Solution Approach 2:
The patent optimizes the molecular weight, functional group density, and chemical composition parameters of the photocurable resin components. By controlling the silane content, molecular weight of polyether polyol, and ratio of acrylate functional groups, the patent achieves superior mechanical properties including enhanced toughness and durability while keeping the manufacturing process simple and straightforward
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 allows for the production of stereolithographic objects with improved strength, reduced warping, and increased efficiency by shortening photocuring time, enhancing tensile strength, bending strength, and repeated bending strength, while maintaining flexibility and heat resistance.
Implementation Method 1
a composition for optical stereolithography which includes at least: (A1) a radical polymerizable compound of a dioxane (meth)acrylate, (A2) a radical polymerizable compound of a bifunctional polyester-based urethane (meth)acrylate, (A3) a radical polymerizable compound of a bifunctional polyether-based urethane (meth)acrylate... and (B) a photopolymerization initiator; and (C) a sensitizer
Data Source
AI summary
Provided is a composition for optical stereolithography the stereolithography (photocuring) of which is completed in a shorter time and which provides a stereolithographic object having excellent strength (for example, strength that prevents the occurrence of a fracture and the like when the stereolithographic object is subjected to an impact or dropping, and strength that allows the stereolithographic object to withstand repeated folding). The composition for optical stereolithography of the present invention includes at least 2 to 40% by mass of (A1) a radical polymerizable compound of a dioxane (meth)acrylate, 5 to 40% by mass of (A2) a radical polymerizable compound of a bifunctional polyester-based urethane (meth)acrylate, 5 to 40% by mass of (A3) a radical polymerizable compound of a bifunctional polyether-based urethane (meth)acrylate, and 20 to 87% by weight of (A4) a radical polymerizable compound other than the (A1), (A2), and (A3), as (A) radical polymerizable compounds; 0.1 to 5% by mass of (B) a photopolymerization initiator; and 0.1 to 5% by mass of (C) a sensitizer.