Tin-Free Mold Release Agent for Polythiourethane Optical Materials

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Solution Overview

Problem

The production of polythiourethane optical materials faces challenges with conventional mold release agents, including difficulties in achieving homogeneous release, surface precision, and transparency issues, particularly due to the use of organic tin catalysts which are toxic and subject to regulatory restrictions, and require separate addition of polymerization catalysts, leading to potential thermal inhomogeneities and reduced pot life.

Innovation Solution

A tin-free internal mold release agent with polymerization catalytic activity is developed by mixing an acidic phosphate ester compound with zinc, which combines the functions of a mold release agent and polymerization catalyst, eliminating the need for separate additives and enhancing catalytic activity and weather resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional organic tin catalysts (DBTDL, DBC) are used for polymerization, then high catalytic activity is achieved, but toxicity and safety problems arise due to environmental hormone risks and regulatory restrictions

Engineering Contradiction:

Improvecatalytic activityVSAvoidtoxicity and safety

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters by replacing organic tin catalysts with zinc-based catalysts combined with acidic phosphate ester compounds. This substitution maintains catalytic activity while eliminating the toxicological hazards associated with tin compounds, particularly tributyltin environmental hormones

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses zinc, which is less expensive and less hazardous than organic tin compounds. The zinc-based catalyst system provides sufficient catalytic activity for the polymerization process without the long-term environmental and health concerns associated with tin catalysts

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If separate polymerization catalyst and mold release agent are added, then both functions are fulfilled, but process complexity increases and thermal inhomogeneity may occur

Engineering Contradiction:

Improvefunctional completenessVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the functions of the polymerization catalyst and mold release agent into a single integrated system. The zinc-based catalyst combined with acidic phosphate ester compound simultaneously provides catalytic activity for polymerization and release agent properties, eliminating the need for separate additives and simplifying the manufacturing process

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The zinc-based catalyst system with acidic phosphate ester exhibits multi-functionality, serving both as a polymerization catalyst and as a mold release agent. This universal additive performs multiple critical functions that previously required separate substances, reducing process complexity and potential sources of error

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If conventional internal mold release agents (aliphatic alcohols, fatty acid esters, fluorine type surface active agents) are used, then release function is provided, but transparency and surface quality deteriorate

Engineering Contradiction:

Improverelease functionVSAvoidtransparency and surface quality

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The invention changes the chemical nature of the release agent from conventional aliphatic alcohols, fatty acid esters, or fluorine compounds to a zinc-based system with acidic phosphate ester. This parameter change maintains effective mold release functionality while preserving the optical transparency and surface quality required for high-quality optical materials

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 solution provides a simplified process for producing polythiourethane optical materials with improved transparency, heat resistance, and weather stability, while ensuring safety and compliance with regulatory standards by eliminating the use of organic tin compounds.

Implementation Method 1

an internal mold release agent having a polymerization catalytic activity, that is, a substance obtained by mixing an acidic phosphate ester compound and at least one metal including Zn

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

there is also a problem such that during the polymerization, exothermic heat is locally generated so that optical inhomogeneity is easily exhibited to lenses

Methodology Applied

Scientific EffectExothermic reaction: Exothermic Reaction

Data Source

PatentEP1988110B1Internal mold release agent for production of polythiourethane optical material

Publication Date: 2017.01.04 MITSUI CHEMICALS INC

AI summary

Disclosed is an internal mold release agent for the production of polythiourethane optical materials, which is obtained by mixing an acidic phosphate ester compound and at least one metal selected from the group consisting of Zn, Cu, Fe, Ga, Bi, Al and Zr. The internal mold release agent for the production of polythiourethane optical materials contains the metal in an amount of 0.01 to 20 weight %.