Multilayer Member Adhesion via Controlled Dry Treatment

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Solution Overview

Problem

The adhesion of multilayer members produced using dry treatments without a primer is not sufficiently strong, failing to meet the increased requirements for automobile safety and fuel efficiency.

Innovation Solution

A method involving dry treatments like corona, plasma, or flame treatments on crystallizable thermoplastic resin surfaces, followed by adhesive application without a primer, ensuring specific temperature conditions are met to enhance adhesion, specifically with the ultimate temperature being below the peak endothermic temperature and high temperature holding time under 3 seconds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a dry treatment is performed without a primer composition, then the manufacturing process is simplified and production efficiency is improved, but the adhesion strength of the multilayer member becomes insufficient

Engineering Contradiction:
Improveproduction efficiencyVSAvoidadhesion strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The invention changes the temperature parameters during dry treatment by controlling the ultimate temperature and high temperature holding time to prevent resin melting while achieving sufficient surface activation for adhesive bonding, thereby eliminating the need for primer composition

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite materials consisting of crystallizable thermoplastic resin and inorganic substances, where the inorganic substances remain unaffected by the controlled temperature treatment and provide stable adhesion sites for the adhesive layer

Inventive Principle:
Principle #40Composite materials

2Strength

If the temperature during dry treatment is increased to improve surface activation, then the adhesion is enhanced, but the crystallizable thermoplastic resin melts and deteriorates the adhesion

Engineering Contradiction:
ImproveadhesionVSAvoidresin melting temperature
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The invention precisely controls the temperature parameters during dry treatment by setting the ultimate temperature and high temperature holding time within specific ranges that activate the resin surface for bonding without causing melting or degradation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies partial heating that is sufficient to activate the surface for adhesion but deliberately stops short of the temperature required to melt the resin, achieving the desired effect without excessive thermal exposure

Inventive Principle:
Principle #16Partial or excessive 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

This method produces multilayer members with excellent adhesion properties, suitable for automotive parts, improving both safety and fuel efficiency by stabilizing the adhesive layer on the hydrophilic surface and utilizing the crystal structure as an anchor.

Implementation Method 1

the dry treatment is at least one selected from the group consisting of a corona treatment, a plasma treatment, a flame treatment, ITRO treatment, an UV treatment, and an excimer treatment

Methodology Applied
Scientific EffectCorona treatment: Corona Discharge

Implementation Method 2

the dry treatment is at least one selected from the group consisting of a corona treatment, a plasma treatment, a flame treatment, ITRO treatment, an UV treatment, and an excimer treatment

Methodology Applied
Scientific EffectPlasma treatment: Plasma

Implementation Method 3

the dry treatment is at least one selected from the group consisting of a corona treatment, a plasma treatment, a flame treatment, ITRO treatment, an UV treatment, and an excimer treatment

Methodology Applied
Scientific EffectFlame treatment: Combustion

Implementation Method 4

an adhesive application step of applying an adhesive to the surface of the first member subjected to the dry treatment without a primer composition, the first member being subjected to only the dry treatment as a surface treatment, to form an adhesive layer on the surface

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3406425B1Method for producing multilayer member
Publication Date: 2023.08.16 SIKA TECH AG
  • EP3406425B1 patent drawingFigure 1A~2
  • EP3406425B1 patent drawingFigure 3

AI summary

Provided is a method for producing a multilayer member exhibiting excellent adhesion. A method for producing a multilayer member having a first member containing a crystallizable thermoplastic resin, an adhesion layer, and a second member in this order includes a surface treatment step of performing a dry treatment on a surface of the first member containing a crystallizable thermoplastic resin so as to satisfy the following conditions A and B, an adhesive application step of applying an adhesive to the surface of the first member subjected to the dry treatment without a primer composition, to form an adhesive layer on the surface, and an adhering step of adhering the second member to the adhesive layer. (A) The ultimate temperature of the first member is lower than the peak temperature of endothermic peak obtained by differential scanning calorimetry of the crystallizable thermoplastic resin. (B) The high temperature holding time of the first member is less than 3.0 seconds. Herein, the high temperature holding time of the first member is a time when the first member is continuously held at a temperature not lower than a temperature at the starting point of the endothermic peak obtained by differential scanning calorimetry of the crystallizable thermoplastic resin.