Aqueous Adhesive Composition for Polyolefin Bonding

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Solution Overview

Problem

Existing adhesive compositions for automobile interior parts, particularly those made of polyolefin, face challenges in achieving strong adhesion, heat resistance, and environmental safety, as they often rely on polychloroprene-based adhesives that emit solvent gases during application and drying.

Innovation Solution

A one-pack thermosetting aqueous adhesive composition comprising acid-modified polyolefin-based resin and a core-shell hardener, where the core is capable of cross-linking with the resin and the shell is an acrylic copolymer, optionally including an amine-based hardener, to enhance storage stability, adhesion, and heat resistance without solvent gas emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a polychloroprene-based adhesive is used for bonding polyolefin automobile interior parts, then adhesion is achieved, but solvent gas is emitted during application and drying causing environmental safety issues

Engineering Contradiction:
Improvesolvent gas emissionVSAvoidadhesion performance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention changes the fundamental parameter of the adhesive system from solvent-based to water-based. The aqueous adhesive composition uses water as the solvent instead of organic solvents, eliminating harmful solvent gas emissions while maintaining adhesion performance through the specific polymer composition and cross-linking mechanism described in the patent

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs a composite adhesive system combining acrylic polymer, polyolefin resin, and cross-linking agents. This composite formulation achieves both environmental safety (no solvent emission) and reliable adhesion to polyolefin substrates through the synergistic effects of the different components working together

Inventive Principle:
Principle #40Composite materials

2Strength

If a polyolefin resin modified with unsaturated carboxylic acid is used as an adhesive, then adhesion to polyolefin is improved, but heat resistance and storage stability are insufficient

Engineering Contradiction:
Improveadhesion to polyolefinVSAvoidheat resistance
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The invention incorporates cross-linking agents (epoxy resin, polyisocyanate, or carboxylic acid anhydride) in the adhesive formulation before application. These agents pre-position the capability for heat-resistant cross-linked network formation, which activates during curing to provide the necessary heat resistance while maintaining the adhesion benefits of the acid-modified polyolefin

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The adhesive is formulated as a composite system combining acid-modified polyolefin resin with cross-linking agents and acrylic polymer. This composite structure provides both the adhesion to polyolefin surfaces (from the acid-modified component) and the heat resistance (from the cross-linked network formed by the hardening agents)

Inventive Principle:
Principle #40Composite materials

3Strength

If a one-pack thermosetting aqueous adhesive is formulated with cross-linking agents, then heat resistance and adhesion are enhanced, but storage stability may be compromised

Engineering Contradiction:
Improveheat resistanceVSAvoidstorage stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The cross-linking agents are incorporated into the adhesive formulation in advance (preliminary action), but the actual cross-linking reaction is controlled to occur slowly or remain dormant during storage. The cross-linked network forms progressively during application and curing, providing heat resistance while maintaining storage stability through controlled reaction kinetics

Inventive Principle:
Principle #10Preliminary action

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 composition provides excellent storage stability, adhesion to polyolefin surfaces, and heat resistance, making it suitable for use in vacuum-molding processes for automobile interior parts without the environmental concerns associated with solvent gas emission.

Implementation Method 1

a core of the core-shell hardener (B) comprises a compound which is capable of cross-linking to the acid-modified polyolefin-based resin (A)

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Data Source

PatentUS9359536B2Aqueous adhesive agent composition
Publication Date: 2016.06.07 SUNSTAR GIKEN KK

AI summary

Disclosed is an aqueous adhesive agent composition which has no concern about environmental safety and can be used as an adhesive agent composition for automobile interior materials. The aqueous adhesive agent composition comprises (A) an acid-modified polyolefin resin and (B) a core-shell-type curing agent.