Photocurable Hydrogel Composition UV Shielding
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Solution Overview
Problem
Hydrophilic resin compositions used in hydrogels for biological applications, such as soft contact lenses, face challenges with ultraviolet shielding due to issues like discoloration and poor curing caused by organic ultraviolet absorbers and photocatalytic activity of metal oxides like titanium oxide during ultraviolet curing.
Innovation Solution
A photocurable composition comprising a monomer with a (meth)acryloyl structure, a crosslinking agent, an inorganic ultraviolet-blocking agent with a specific particle size distribution, and a photopolymerization initiator, where the inorganic agent is a core-shell type titanium oxide particle with tin and manganese solid solution to minimize photocatalytic activity and ensure effective ultraviolet shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an organic ultraviolet absorber is used to provide ultraviolet shielding function, then the ultraviolet shielding ability is improved, but discoloration or white turbidity occurs due to photo- or heat-decomposition of the organic ultraviolet absorbers
Solution Approach 1:
The patent changes the chemical composition parameter by replacing organic ultraviolet absorbers with inorganic metal oxide particles (titanium oxide, zinc oxide, or their combinations) having specific particle size distributions (D10: 1-100 nm, D50: 10-500 nm, D90: 10-1000 nm). This parameter change eliminates the discoloration and turbidity issues while maintaining ultraviolet shielding functionality.
Solution Approach 2:
The patent uses composite materials by combining inorganic metal oxide particles with hydrophilic resin components in a specific weight ratio range (0.1-10 parts by weight relative to 100 parts by weight of components (A) and (B)). This composite approach provides both ultraviolet shielding and maintains the desired optical properties without decomposition issues.
2Object-affected harmful factors
If metal oxides such as titanium oxide and zinc oxide are used as ultraviolet shielding agents, then the ultraviolet shielding ability is improved without easy photo- or heat-decomposition, but photocatalytic activity decomposes surrounding resin or organic material under ultraviolet irradiation
Solution Approach 1:
The patent changes the particle size parameter of metal oxide particles to a specific distribution range (D10: 1-100 nm, D50: 10-500 nm, D90: 10-1000 nm) which reduces photocatalytic activity while maintaining ultraviolet shielding capability. This parameter optimization allows the metal oxides to protect against UV without excessively decomposing surrounding organic materials.
Solution Approach 2:
The patent applies local quality by controlling the particle size distribution of metal oxide particles within specific ranges. The different particle size fractions (D10, D50, D90) are optimized to provide localized UV shielding at different depths and wavelengths, reducing overall photocatalytic damage while maintaining protective function.
3Reliability
If the amount of ultraviolet exposure or the amount of ultraviolet polymerization initiator is increased to suppress poor curing, then the curing ability is improved, but discoloration or decomposition of the composition is caused
Solution Approach 1:
The patent changes the composition parameters by incorporating inorganic metal oxide particles with specific particle size distributions and controlling the weight ratios of components (A), (B), and (C) within specified ranges. This parameter optimization enables effective curing with reduced initiator amounts and shorter exposure times, preventing discoloration and decomposition while maintaining reliable curing.
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 achieves good ultraviolet curing with reduced photopolymerization initiator and light exposure, providing a hydrogel with excellent visible light transmittance and ultraviolet shielding properties suitable for biological applications like ophthalmic devices.
Implementation Method 1
an inorganic ultraviolet-blocking agent having a 50% volume cumulative particle size of 1 to 50 nm
Implementation Method 2
inorganic ultraviolet-blocking agent having a 50% volume cumulative particle size of 1 to 50 nm in the particle size distribution
Implementation Method 3
a photopolymerization initiator in an amount of 0.05 to 1 part by weight, relative to total 100 parts by weight of components (A) and (B)
Data Source
AI summary
A photocurable composition including the following components (A) to (D), (A) a monomer having one (meth)acryloyl structure, (B) a crosslinking agent having two or more (meth)acryloyl structures, (C) an inorganic ultraviolet-blocking agent having a 50% volume cumulative particle size of 1 to 50 nm, and (D) a photopolymerization initiator in an amount of 0.05 to 1 part by weight, relative to total 100 parts by weight of components (A) and (B), wherein a part or all of component (A) is a hydrophilic monomer, and a content of the hydrophilic monomer is 70% by weight or more, relative to the total weight of components (A) and (B).