Modified Polyolefin Resin for High-Temperature Adhesion

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Solution Overview

Problem

Conventional modified polyolefin resins used as primers for resin substrates in automotive applications fail to provide sufficient water-resistant adhesiveness under high temperature conditions, leading to cohesion fractures in coating films.

Innovation Solution

A graft-modified polyolefin resin with a melting point of 85° C. or higher and lower than 110° C., a tensile modulus of 250 MPa or more, and a weight-average molecular weight of 70,000 to 200,000, achieved by modifying polyolefin resins with α,β-unsaturated carboxylic acids or their derivatives, is used to enhance water-resistant adhesiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional modified polyolefin resin is used as primer for resin substrate, then adhesion to substrate is improved, but water-resistant adhesiveness under high temperature condition deteriorates

Engineering Contradiction:
Improvewater-resistant adhesivenessVSAvoidhigh temperature condition
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies parameter changes by precisely controlling the melting point (85-110°C), tensile modulus (≥250 MPa), and weight-average molecular weight (70,000-200,000) of the modified polyolefin resin. These parameter adjustments optimize the resin's thermal stability and mechanical properties to maintain adhesion under high temperature conditions while ensuring water resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by graft-modifying polyolefin resin with α,β-unsaturated carboxylic acid or its derivative, creating a modified polyolefin resin that combines the advantages of both components - the polyolefin provides water resistance and chemical stability, while the grafted carboxylic acid group enhances adhesion and thermal performance.

Inventive Principle:
Principle #40Composite materials

2Strength

If conventional modified polyolefin resin is used, then ease of manufacture is maintained, but coating film strength under high temperature deteriorates

Engineering Contradiction:
Improvecoating film strengthVSAvoidmanufacturing simplicity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent maintains ease of manufacture by using a straightforward graft-modification process with controlled parameters (melting point 85-110°C, tensile modulus ≥250 MPa, molecular weight 70,000-200,000). The modified polyolefin resin can be processed using conventional manufacturing methods while achieving superior coating film strength under high temperature conditions.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional polyolefin resin is used, then cost is reduced, but adhesion to polar coating material deteriorates

Engineering Contradiction:
ImproveadhesivenessVSAvoidresin modification complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a composite material by grafting α,β-unsaturated carboxylic acid or its derivative onto polyolefin resin chains. This modifies the nonpolar polyolefin surface to provide polar groups that enhance adhesion to polar coating materials like urethane and acrylic, while maintaining the cost-effectiveness of polyolefin-based resins.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by introducing polar carboxylic acid groups specifically at the surface or graft regions of the polyolefin resin molecules, while maintaining the nonpolar backbone structure. This localized modification provides the necessary adhesion to polar coatings without requiring complete resin reformulation.

Inventive Principle:
Principle #3Local quality

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 modified polyolefin resin produces a coating film with superior water-resistant adhesiveness under high temperature conditions, maintaining film strength and adhesiveness, while ensuring solubility and stability for effective film formation.

Implementation Method 1

a modified polyolefin resin with an added polar group (a carboxy group, an acid anhydride group, or the like) is used. Here, by adding the polar group, not only an affinity to a polyolefin type resin substrate but also an affinity to the urethane resin type coating material or the like is enhanced, thereby enhancing the adhesiveness

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS12071499B2Modified polyolefin resin and dispersion composition thereof
Publication Date: 2024.08.27 NIPPON PAPER IND CO LTD

AI summary

The present invention has an object to provide a modified polyolefin resin capable of forming a coating film that is excellent in water-resistant adhesiveness under a high temperature condition. The present invention provides a modified polyolefin resin including a graft-modified product in which a component (A) that is a polyolefin resin is graft-modified with a component (B) that is an α,β-unsaturated carboxylic acid or a derivative thereof, and having a tensile modulus of 250 MPa or higher, and a weight-average molecular weight of 70,000 or more and less than 200,000.