Photocurable Coating Composition with Core-Shell Titanium Oxide

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Solution Overview

Problem

Current photocurable coating compositions lack long-term UV-shielding capability while maintaining transparency, as organic UV absorbers are not weather-resistant and inorganic UV absorbers like titanium oxide are difficult to uniformly disperse without compromising transparency.

Innovation Solution

The development of photocurable coating compositions using core/shell type microparticles with a titanium oxide core and silicon oxide shell, treated with specific surface agents, combined with a photopolymerizable monomer and photoinitiator, to achieve uniform dispersion and enhanced UV-shielding without sacrificing transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If organic UV absorbers are added to photocurable coating compositions, then UV-shielding capability is improved, but weathering stability deteriorates

Engineering Contradiction:
ImproveUV-shielding capabilityVSAvoidweathering stability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent transitions from organic UV absorbers to inorganic titanium oxide particles, changing the material parameter from organic to inorganic. This fundamental parameter change resolves the contradiction because inorganic titanium oxide provides both UV-shielding capability and weathering stability, eliminating the degradation issue inherent in organic UV absorbers while maintaining photocurable properties through surface treatment with silane compounds.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by combining titanium oxide particles with silane surface treatment agents. The silane treatment creates a hybrid interface that allows inorganic titanium oxide to disperse uniformly in the organic photocurable resin system. This composite approach enables the inorganic particles to provide UV-shielding and weathering stability while the silane treatment ensures compatibility and uniform dispersion in the photocurable coating matrix.

Inventive Principle:
Principle #40Composite materials

2Reliability

If inorganic UV absorbers like titanium oxide are added to photocurable coating compositions, then weathering stability is improved, but uniform dispersion deteriorates

Engineering Contradiction:
Improveweathering stabilityVSAvoiduniform dispersion
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces silane surface treatment agents as intermediary substances between the inorganic titanium oxide particles and the organic photocurable resin. The silane treatment modifies the particle surface to be compatible with the organic resin system, acting as a mediator that enables uniform dispersion. This intermediary treatment resolves the dispersion issue while preserving the weathering stability benefits of inorganic titanium oxide.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the surface parameter of titanium oxide particles through silane treatment. By modifying the surface chemistry of the inorganic particles, the treatment alters their interfacial properties to enable uniform dispersion in the organic photocurable resin without compromising the inherent weathering stability of the inorganic material.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If titanium oxide particles are uniformly dispersed in photocurable coating compositions, then transparency is improved, but UV-shielding capability deteriorates

Engineering Contradiction:
Improveuniform dispersionVSAvoidUV-shielding capability
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the particle size parameter of titanium oxide, using fine particles with specific size ranges that allow uniform dispersion while maintaining UV-shielding capability. The silane surface treatment further modifies particle parameters to enhance dispersion without requiring particle aggregation, thereby preserving both transparency and UV-protection functionality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system where silane-treated titanium oxide particles are integrated into the photocurable resin matrix. This composite structure allows the particles to remain uniformly dispersed (maintaining transparency) while the silane treatment ensures sufficient particle-resin interaction to maintain UV-shielding capability through the cured coating.

Inventive Principle:
Principle #40Composite materials

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 provides transparent coatings with improved UV-shielding performance, resistance to UV-induced degradation, and maintains aesthetic appearance over time, while ensuring mar resistance and stability.

Implementation Method 1

a photopolymerizable monomer or oligomer and a photoinitiator to formulate a photocurable coating composition

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

photocurable coating compositions comprising titanium oxide, for forming transparent coatings having good long-term UV-shielding capability

Methodology Applied
Scientific EffectUV absorption: Absorption (EM radiation)

Data Source

PatentEP2865720B1Photocurable coating composition, laminate, and automotive headlamp covering sheet
Publication Date: 2017.05.03 SHIN ETSU CHEMICAL CO LTD
  • EP2865720B1 patent drawingFigure 1
  • EP2865720B1 patent drawingFigure 2
  • EP2865720B1 patent drawingFigure 3~5

AI summary

A photocurable coating composition is provided comprising (1) surface-treated titanium oxide comprising core/shell type microparticles each consisting of a titanium oxide core and a silicon oxide shell, which are treated with two surface treating components having formula (I): R1Si(OR2)3 wherein R1 is an organic group which may have a (meth)acrylic moiety, and R2 is alkyl, and formula (II): (R3R4 2Si)2NH wherein R3 is an organic group which may have a (meth)acrylic moiety, and R4 is alkyl, (2) a photopolymerizable monomer or oligomer, and (3) a photoinitiator. The composition has good transparency and mar resistance despite titanium oxide loading.