Transparent Curable Composition Using Hindered-Amine Stabilizer

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Solution Overview

Problem

Polyoxyalkylene-based polymers with reactive silicon groups face challenges in maintaining weather resistance and transparency due to susceptibility to light and heat, and existing stabilizers often cause discoloration or require high amounts of fillers like calcium carbonate, making it difficult to achieve a transparent, color-stable cured product.

Innovation Solution

Incorporating a specific weathering stabilizer with a long-chain hydrocarbon group, such as a hindered-amine-based photostabilizer, which enhances weather resistance and heat resistance while preventing coloration, and using a combination of polymers and additives to maintain transparency and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polyoxyalkylene-based polymer with reactive silicon groups is used, then the polymer can be crosslinked to form a cured product, but the polymer is susceptible to light and heat causing poor weather resistance

Engineering Contradiction:

Improveweather resistanceVSAvoidsusceptibility to light and heat

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a hindered-amine-based photostabilizer as an intermediary substance to protect the polyoxyalkylene-based polymer from harmful light and heat effects. The photostabilizer absorbs UV radiation and free radicals, acting as a mediator between the polymer and environmental stressors, thereby preventing degradation while maintaining the polymer's crosslinking capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite system by combining the polyoxyalkylene-based polymer with a hindered-amine-based photostabilizer. This composite formulation integrates the crosslinking functionality of the polymer with the protective properties of the photostabilizer, achieving both structural integrity and weather resistance in the cured product

Inventive Principle:

Principle #40Composite materials

2Reliability

If hindered-amine-based photostabilizers are added to improve weather resistance, then weather resistance is enhanced, but the cured product may discolor

Engineering Contradiction:

Improveweather resistanceVSAvoidcolor stability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent optimizes the molecular weight parameter of the hindered-amine-based photostabilizer, selecting high molecular weight variants that provide superior weather resistance while minimizing discoloration. By changing this critical parameter, the patent achieves a balance between protective functionality and color stability that lower molecular weight stabilizers cannot provide

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies the hindered-amine-based photostabilizer specifically to address UV degradation concerns in the polyoxyalkylene-based polymer system. The stabilizer is positioned to provide localized protection where it is most needed (against photo-oxidation) while minimizing interference with the polymer's crosslinking chemistry and final product appearance

Inventive Principle:

Principle #3Local quality

3Strength

If calcium carbonate filler is added to improve reinforcing properties, then strength is enhanced, but transparency of the cured product is reduced

Engineering Contradiction:

Improvereinforcing propertyVSAvoidtransparency

Core Design Contradiction:

StrengthVSShape

Solution Approach 1:

The patent extracts or eliminates calcium carbonate filler from the formulation to maintain transparency. By removing this white pigment that provides reinforcement but compromises optical clarity, the patent creates a transparent cured product that relies on the polyoxyalkylene-based polymer's intrinsic properties and crosslinking structure for mechanical strength rather than filler reinforcement

Inventive Principle:

Principle #2Taking out (Extraction)

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 curable composition achieves excellent weather resistance, heat resistance, and transparency in the cured product, preventing discoloration and maintaining stability over time without the need for excessive fillers, ensuring a transparent and effective sealant or adhesive.

Implementation Method 1

an organic polymer containing at least one reactive silicon group in the molecule is crosslinked by the formation of a siloxane bond, which is accompanied by hydrolysis and the like of the reactive silicon group due to moisture and the like even at room temperature

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

crosslinked by the formation of a siloxane bond

Methodology Applied

Scientific EffectSiloxane bond formation: Chemical Bonding

Data Source

PatentEP3378898B2Curable composition and cured product thereof

Publication Date: 2023.02.08 KANEKA CORP

AI summary

Provided is a transparent curable composition which uses a polyoxyalkylene-based organic polymer having a reactive silicon group and a weathering stabilizer having a specific structure, a cured product of the curable composition having not only excellent surface weather resistance over a long period of time, but good heat resistance as well. A curable composition and a cured product of the same, the curable composition containing a polyoxyalkylene-based polymer (A) having a reactive silicon group, and a hindered-amine-based photostabilizer and/or a hindered-phenol-based antioxidant (B) having a long-chain hydrocarbon group.