Curable Composition for Optical Molding Mold Durability

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Solution Overview

Problem

Current curable compositions used in silicone molds for producing optical components tend to permeate through the molds, causing swelling and reducing their durability and service life, leading to inaccurate and costly results.

Innovation Solution

A curable composition comprising a cycloaliphatic epoxy compound, an oxetane compound, and a glycidyl ether epoxy compound, with specific molecular weight and solubility parameters, that minimizes permeation through silicone molds, ensuring excellent chargeability, curability, and heat resistance while maintaining mold durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a photocurable composition including epoxy resin is used, then curability is improved, but the silicone molds swell gradually and durability decreases

Engineering Contradiction:
ImprovecurabilityVSAvoidservice life of silicone molds
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical composition parameters of the curable composition by specifying particular epoxy compounds (cycloaliphatic epoxy compound with molecular weight 300-900, glycidyl ether epoxy compound with molecular weight 350-1500) and their content ratios. This parameter optimization reduces permeation into silicone molds while maintaining curability, thereby extending mold service life.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite curable composition system combining multiple epoxy compounds (cycloaliphatic epoxy, glycidyl ether epoxy, and other epoxy compounds) with oxetane compounds and photoinitiators. This composite formulation achieves balanced properties: sufficient curability from epoxy content while reduced permeation through controlled molecular weight distribution and compound selection.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If curable composition with low molecular weight is used, then chargeability into molds is improved, but permeation through silicone molds increases

Engineering Contradiction:
Improvechargeability into moldsVSAvoidpermeation through silicone molds
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes the molecular weight parameter of the epoxy compounds within specific ranges (cycloaliphatic epoxy: 300-900, glycidyl ether epoxy: 350-1500). This parameter control ensures the composition remains fluid enough for good chargeability into molds while being heavy enough to reduce permeation, resolving the contradiction between ease of operation and harmful permeation effects.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If repeated use of silicone molds is required, then manufacturing cost is reduced, but mold swelling from permeation reduces accuracy

Engineering Contradiction:
Improverepeated use of moldsVSAvoidshape transfer accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the compositional parameters to reduce permeation, specifically controlling the molecular weights and types of epoxy compounds. This reduction in permeation prevents mold swelling during repeated use, thereby maintaining shape transfer accuracy and enabling productive repeated mold usage without degradation.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If heat resistance is improved in cured product, then manufacturing precision is improved, but mold swelling increases

Engineering Contradiction:
Improveheat resistance of cured productVSAvoidmold swelling
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes parameters by selecting specific epoxy compounds with appropriate molecular weights and controlling their content ratios. This parameter optimization achieves heat resistance in the cured product through sufficient crosslinking density while simultaneously reducing permeation-induced mold swelling, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #35Parameter changes

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 repeated use of silicone molds with improved durability and accuracy in producing optical components, offering economic efficiency and high-quality optical components with excellent shape transferability and heat resistance.

Implementation Method 1

a photoinitiator for generating radicals by action of UV light

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

this curable composition is liable to permeate through silicone molds, thereby causes the silicone molds to swell gradually

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentEP3336121B1Curable composition and cured product from same
Publication Date: 2021.07.28 DAICEL CORP
  • EP3336121B1 patent drawingFigure 1
  • EP3336121B1 patent drawingFigure 2~4
  • EP3336121B1 patent drawing

AI summary

Provided is a curable composition which has chargeability into silicone molds and curability at excellent levels, less causes the silicone molds to swell, and allows the silicone molds to have better durability and a longer service life in repeated use. The curable composition according to the present invention contains curable compounds and a cationic initiator and is used for production of an optical component by molding using silicone molds. The curable compounds include (A) a cycloaliphatic epoxy compound in a content of 10 weight percent or more of the totality of all the curable compounds contained in the curable composition. Of the totality of all the curable compounds contained in the curable composition, 10 to 50 weight percent is a curable compound or compounds having a molecular weight of 400 or more.