Silane-Modified Adhesive Set for Primer-Free Polypropylene Bonding

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Solution Overview

Problem

Existing adhesive compositions for polypropylene materials lack non-primer adhesiveness and sufficient heat aging resistance, making it difficult to adhere polypropylene base materials without a primer treatment and compromising durability.

Innovation Solution

An adhesive agent set comprising a main agent with a urethane prepolymer and an oligomer of hexamethylene diisocyanate modified with a silane coupling agent, and a hardening agent with a polyol, which enhances adhesion and heat resistance without the need for a primer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a two-liquid type hardenable composition containing isocyanate compound and ketimine is used, then quick hardening and sufficient working life are achieved, but non-primer adhesiveness and heat aging resistance are insufficient

Engineering Contradiction:
Improveworking lifeVSAvoidheat aging resistance
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive system by replacing ketimine with a polyol-based hardening system. This parameter change enables both sufficient working life and improved heat aging resistance, resolving the contradiction between durability and working time.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite adhesive system comprising a main agent with urethane prepolymer and isocyanate-modified silane, combined with a polyol hardening agent. This composite approach achieves both non-primer adhesiveness on polypropylene and heat aging resistance, overcoming the limitations of single-component systems.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If polypropylene base material is used without primer treatment, then process simplification is achieved, but adhesion strength is insufficient

Engineering Contradiction:
Improveprocess simplificationVSAvoidadhesion strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent introduces an intermediary adhesive composition containing silane-modified isocyanate groups that acts as a bridge between the polypropylene base material and the hardening agent. This intermediary enables direct adhesion to polypropylene without primer treatment while maintaining strong bond strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention modifies the chemical parameters of the adhesive system by incorporating silane coupling agents with specific functional groups that are compatible with polypropylene surfaces. This parameter modification enables direct bonding to polypropylene without requiring primer treatment, achieving both process simplification and adequate adhesion strength.

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 adhesive agent set provides excellent non-primer adhesiveness and heat aging resistance, ensuring strong and durable bonding of polypropylene materials.

Implementation Method 1

an oligomer of hexamethylene diisocyanate having an isocyanate group modified with a silane coupling agent having a mercapto group or an amino group

Methodology Applied
Scientific EffectSilane coupling: Chemical Bonding

Implementation Method 2

the main agent contains a urethane prepolymer having an isocyanate group as a terminal group; and the hardening agent contains a polyol

Methodology Applied
Scientific EffectUrethane formation: Chemical Bonding

Data Source

PatentUS12391854B2Adhesive agent set and method for manufacturing structural body
Publication Date: 2025.08.19 RESONAC CORP

AI summary

Disclosed is an adhesive agent set composed of a main agent and a hardening agent, in which the main agent contains a urethane prepolymer having isocyanate groups as terminal groups; and an oligomer of hexamethylene diisocyanate having an isocyanate group modified with a silane coupling agent having a mercapto group or an amino group, the oligomer also having at least two unmodified isocyanate groups, and the hardening agent contains a polyol.