Polyurethane Organic Glass via UV Photopolymerization
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Solution Overview
Problem
Existing processes for producing organic glass, such as those using Allyl Diglycol Carbonate (ADC), face challenges including high costs, safety risks due to peroxide initiators, and limitations in achieving enhanced optical and mechanical properties like high toughness and impact strength.
Innovation Solution
A polymerizable liquid composition of polyurethane type, comprising a cyclo-aliphatic diisocyanate monomer and a polyol, with an acid phosphate ester catalyst, which allows for a casting process with extended pot-life, enabling the production of organic glass with improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If peroxide initiators (IPP) are used for ADC polymerization, then polymerization reaction can be initiated, but safety risks increase due to thermal instability and transportation/storage difficulties
Solution Approach 1:
The harmful peroxide initiator is extracted and replaced with a safe photoinitiator system. The patent uses photoinitiators that decompose under UV light to generate free radicals, completely eliminating the need for thermally unstable peroxide initiators and their associated safety risks during storage and transportation.
Solution Approach 2:
The thermal polymerization mechanism initiated by peroxide is replaced with a photochemical polymerization mechanism. Instead of using thermal energy to activate peroxide decomposion, the patent employs UV light irradiation to activate photoinitiators, substituting a safe optical field for a hazardous chemical system.
2Reliability
If ADC polymerization is performed with peroxide initiators, then organic glass can be produced, but operating costs increase due to storage and management requirements
Solution Approach 1:
The patent employs photoinitiators that are stable during storage and only become active when exposed to UV light. This eliminates the need for expensive cold chain storage and special handling procedures required for peroxide initiators, significantly reducing operating costs while maintaining polymerization capability.
3Ease of manufacture
If thermoplastic materials (PMMA, PC) are used for optical applications, then processability is improved, but chemical resistance deteriorates and they melt during mechanical processing
Solution Approach 1:
The patent changes the fundamental chemical structure and bonding parameters of the material. By using photopolymerization to create cross-linked thermosetting networks instead of linear thermoplastic chains, the material achieves both excellent chemical resistance and improved processability through UV curing before final assembly operations.
4Strength
If polycarbonate is used for optical applications, then impact strength is improved, but optical quality deteriorates due to high birefringence and chromatic aberration
Solution Approach 1:
The patent employs composite photopolymer systems containing multiple components: monomers, oligomers, photoinitiators, and UV absorbers. This composite approach allows optimization of both mechanical properties (impact strength) and optical properties (transparency, low birefringence) by carefully selecting and combining materials with complementary characteristics.
5Manufacturing precision
If ADC casting process is used, then good optical properties are achieved, but production time increases to 10-100 hours
Solution Approach 1:
The patent replaces continuous slow thermal polymerization with periodic UV irradiation cycles. The photopolymerization process proceeds in stages under UV light exposure, achieving complete polymerization in minutes or hours rather than days, dramatically increasing productivity while maintaining optical quality.
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 solution achieves organic glass with excellent optical and physico-mechanical properties, including high impact strength and toughness, while simplifying the production process and making it more economically viable for industrial-scale production.
Implementation Method 1
with an acid phosphate ester catalyst, which allows for a casting process with extended pot-life
Implementation Method 2
the production of organic glass having good optical and physico-mechanical properties, starting from polymerizable liquid compositions
Data Source
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AI summary
Polymer izable liquid compositions of the polyurethane type, consisting of two components (A) and (B), wherein component (A) contains at least one cyclo-aliphatic diisocyanate monomer or a mixture of one cyclo-aliphatic diisocyanate monomer and a pre -polymer obtained by reaction, in the presence of an acid phosphate ester catalyst, between said cyclo-aliphatic diisocyanate monomer and one or more polyols having two or more hydroxy 1 groups per molecule and a molecular weight ranging from 50 to 2,000 g/mole; the second component (B) contains one or more polyols having a molecular weight ranging from 50 to 2,000 g/mole and a functionality between 2 and 5; in the absence of polyalkoxylated tertiary diamines and or- ganometallic catalysts, said components (A) and (B) being present in a weight ratio which varies from 1:1 to 2:1 and the process for the production of organic glass starting from polymerizable liquid compositions of the polyurethane type.