Adhesion Primer for Polyolefin Substrates

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Solution Overview

Problem

Existing methods for improving the adhesiveness of poorly bondable materials like polypropylene and polyethylene are costly, decrease productivity, and lack applicability, with current primers failing to achieve practical adhesion levels.

Innovation Solution

A laminate structure comprising a substrate with a primer coat layer containing acid-modified polyolefin and a topcoat layer with a condensation-curable silicone composition, both including an amino group-containing silane coupling agent, enhancing adhesion without plasma irradiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If plasma irradiation is used to improve adhesion of poorly bondable materials, then adhesion is improved, but cost increases and productivity decreases

Engineering Contradiction:
ImproveadhesionVSAvoidproductivity
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent introduces a primer coat layer as an intermediary between the poorly bondable substrate and the topcoat. This primer layer contains specific components (carboxyl group-containing compound and silane coupling agent) that mediate the bonding interface, enabling adhesion improvement through chemical compatibility rather than expensive plasma treatment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces expensive plasma irradiation equipment with a cost-effective primer coat formulation. The primer layer acts as a consumable intermediary that provides the necessary adhesion function without requiring expensive capital equipment or complex process infrastructure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Strength

If plasma irradiation equipment is introduced to improve adhesion, then adhesion is improved, but cost increases

Engineering Contradiction:
ImproveadhesionVSAvoidcost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent substitutes expensive plasma irradiation equipment with an affordable primer coat formulation. The primer layer serves as a low-cost consumable that achieves the adhesion function without requiring capital-intensive equipment or complex manufacturing infrastructure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The primer coat layer acts as a chemical intermediary that provides adhesion through its composition (carboxyl group-containing compound and silane coupling agent) rather than through expensive physical plasma treatment equipment, thereby reducing manufacturing costs.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If conventional primers are used on poorly bondable materials, then coating can be applied, but adhesion remains insufficient

Engineering Contradiction:
Improvecoating applicabilityVSAvoidadhesion
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies local quality by formulating the primer coat with specific functional components (carboxyl group-containing compound and silane coupling agent) that are specifically tailored to interact with poorly bondable substrates. This localized chemical functionality at the substrate-primer interface enables both coating applicability and sufficient adhesion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The primer coat is designed as a composite material combining carboxyl group-containing compounds and silane coupling agents. This composite formulation provides both the wetting properties needed for coating applicability and the chemical bonding capability for sufficient adhesion on poorly bondable substrates.

Inventive Principle:
Principle #40Composite materials

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 laminate exhibits excellent bond strength and durability between the substrate and topcoat layer, achieving high adhesive properties without surface treatment, specifically improving adhesion with polypropylene and polyethylene substrates.

Implementation Method 1

by adding an amino group-containing silane coupling agent to one or both of the primer composition and the topcoat composition and forming the respective layers

Methodology Applied
Scientific EffectSilane coupling: Chemical Bonding

Implementation Method 2

a condensation-curable silicone composition

Methodology Applied
Scientific EffectCondensation reaction: Chemical Bonding

Implementation Method 3

a primer coat layer which is formed of a primer composition containing acid-modified polyolefin

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3401093B1Laminate and method for producing same
Publication Date: 2020.08.26 SHIN ETSU CHEMICAL CO LTD

AI summary

A laminate which comprises a base, a primer coat layer that is formed on at least one surface of the base, and a top coat layer that is formed on the primer coat layer, and wherein: the primer coat layer is formed from a primer composition that contains an acid-modified polyolefin; the top coat layer is formed from a cured product of a top coat composition that contains a condensation-curable silicone composition; and one or both of the primer composition and the top coat composition contain an amino group-containing silane coupling agent. This laminate exhibits good adhesion even in cases where a base that is formed from a slightly adhesive material is used therefor.