UV Curable Silicone Composition for Optical Encapsulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing UV curable silicone compositions for optical element encapsulation require a heating step, which is energy and time intensive, and do not achieve high hardness and refractive index simultaneously.

Innovation Solution

A UV curable silicone composition comprising an organopolysiloxane with a specific terminal group ratio and photopolymerization initiator, along with monofunctional and multifunctional acrylate compounds, allowing for curing without heating and achieving high hardness and refractive index.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If hydrosilylation reaction is used for curing, then curing can be achieved, but heating step is required which consumes energy and time

Engineering Contradiction:

Improveenergy consumptionVSAvoidcuring capability

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The invention changes the curing mechanism from thermal (hydrosilylation requiring heating) to photopolymerization (UV-curable). By incorporating photopolymerizable groups into the silicone polymer structure and using UV irradiation instead of heating, the process eliminates energy-intensive heating steps while maintaining reliable curing capability. The patent specifies using 10-40 mass% of UV curable organopolysiloxane component to achieve this transformation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the thermal curing system (heating apparatus and thermal energy input) with a photopolymerization system (UV light source and photoinitiator). This substitution eliminates the need for heating equipment and thermal energy consumption while achieving the same curing objective through photochemical reaction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If conventional UV curable silicone composition is used, then curing without heating is achieved, but hardness and refractive index are not sufficiently high

Engineering Contradiction:

ImprovehardnessVSAvoidcuring process

Core Design Contradiction:

Manufacturing precisionVSUse of energy by stationary object

Solution Approach 1:

The invention creates a composite material system combining UV curable organopolysiloxane (providing hardness and refractive index) with conventional silicone rubber components. The specific formulation using 10-40 mass% UV curable component, 60-80 mass% conventional silicone rubber, and 1-10 mass% crosslinking agent achieves both high performance properties and energy-efficient curing without heating.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical structure parameters of the silicone polymer by incorporating aromatic groups and photopolymerizable functional groups. These structural modifications enable the material to achieve high hardness (60-80 Shore A) and high refractive index (1.45-1.55) while remaining UV-curable without heating.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If conventional UV curable silicone composition is used, then curing without heating is achieved, but processing time is reduced

Engineering Contradiction:

Improveprocessing speedVSAvoidcuring process

Core Design Contradiction:

ProductivityVSUse of energy by stationary object

Solution Approach 1:

The invention replaces thermal curing with photopolymerization, enabling rapid curing without heating. The UV curable organopolysiloxane component undergoes rapid polymerization upon UV irradiation, dramatically reducing processing time from hours (thermal curing) to minutes or seconds (UV curing), thereby improving productivity while eliminating heating energy consumption.

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 can be quickly cured with UV light, saving energy and time, and produces a product with high hardness and refractive index, suitable for optical element encapsulation.

Implementation Method 1

UV curable silicone composition comprising: (A) 100 parts by mass of an organopolysiloxane... (B) 1 to 10 parts by mass of photopolymerization initiator

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP3222689B1UV curable silicone composition, cured product thereof, optical element encapsulation material comprised of the composition, and optical element encapsulated by the encapsulation material

Publication Date: 2018.11.28 SHIN ETSU CHEMICAL CO LTD

AI summary

A UV curable silicone composition comprises: (A) 100 parts by mass of an organopolysiloxane represented by formula (1) wherein n represents a number satisfying 1 ≤ n ≤ 100, Ar represents an aromatic group, each of F1 and F2 is selected from groups of formulae (2) and (3), and a ratio of the number of terminal groups of the formula (3) to a total number of all the terminal groups is not lower than 20%, wherein each R1 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, wherein m represents a number satisfying 0 ≤ m ≤ 10, each R1 represents a monovalent hydrocarbon group having 1 to 20 carbon atoms, R2 represents an oxygen atom or an alkylene group, and R3 represents an acryloyl group, a methacryloyl group, an acryloyloxyalkyl group or a methacryloyloxyalkyl group; and (B) 0.1 to 10 parts by mass of a photopolymerization initiator.