Acrylic PSA Sheet Primer-Free Adhesion to Olefinic Rubber

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Solution Overview

Problem

Acrylic pressure-sensitive adhesive (PSA) sheets exhibit insufficient adhesion to low-polar adherends such as polyethylene, polypropylene, and olefinic rubber materials, necessitating the use of primer layers which increase environmental stress and costs.

Innovation Solution

A PSA sheet with an acrylic PSA layer and a bubble-containing layer, featuring a high initial peel strength when directly applied to EPDM surfaces without a primer layer, ensuring excellent adhesion and cohesion while reducing the need for primer layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If acrylic PSA is applied directly to olefinic rubber materials, then the adhesive process is simplified and costs are reduced, but the adhesion strength is insufficient

Engineering Contradiction:

Improveadhesive process simplicityVSAvoidadhesion strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent modifies the chemical composition parameters of the acrylic PSA by incorporating specific functional monomers (carboxylic acid group-containing monomers at 5-50 mass% and hydroxyl group-containing monomers at 5-50 mass%) to enhance adhesion to low-polar olefinic rubber surfaces without requiring primer layers

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesive system by combining acrylic polymer with specific functional monomers (carboxylic acid groups and hydroxyl groups) that work synergistically to improve adhesion to olefinic rubber materials while maintaining the base acrylic PSA's weatherability and lightfastness

Inventive Principle:

Principle #40Composite materials

2Strength

If primer layers are used to improve adhesion to olefinic rubber materials, then the adhesion strength increases, but environmental stress and production costs increase

Engineering Contradiction:

Improveadhesion strengthVSAvoidenvironmental stress

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the primer layer component from the adhesive system by incorporating direct-adhesion functional monomers (carboxylic acid and hydroxyl groups) into the acrylic PSA formulation, thereby removing the source of environmental stress associated with primer application while maintaining adhesion strength

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The acrylic PSA formulation performs its own adhesion function directly on olefinic rubber surfaces through the incorporated functional monomers, eliminating the need for separate primer layer application and reducing environmental impact

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9896606B2Pressure-sensitive adhesive sheet and use thereof

Publication Date: 2018.02.20 NITTO DENKO CORP

AI summary

A PSA sheet is provided, having an adhesive face formed of an acrylic PSA layer comprising an acrylic polymer. The PSA sheet has a peel strength of 5 N/10 mm or greater. The peel strength is measured as such that the adhesive face is directly adhered to an ethylene-propylene-diene rubber surface and after 20 minutes, peeled in the 180° direction at a tensile speed of 50 mm/min.