Acrylic Adhesive Composition for EPDM and Rough Surfaces

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Solution Overview

Problem

Conventional adhesive compositions, particularly those using acrylic resins, face challenges in achieving strong adhesion to higher and lower polarity adherends, as well as rough surfaces, and are prone to deterioration in high temperature/high humidity environments, which affects their durability and holding force.

Innovation Solution

An adhesive composition is developed using an acrylic resin copolymerized with specific monomers, including a terminal carboxyl-containing monomer, alkyl (meth)acrylates, and (meth)acrylic acid, which provides improved adhesion to various surfaces and maintains adhesiveness even in harsh conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional acrylic resins are used for adhesive composition, then the adhesive strength to higher polarity adherend is improved, but the adhesive strength to lower polarity adherend and rough surface deteriorates

Engineering Contradiction:
Improveadhesive strength to higher polarity adherendVSAvoidadhesive strength to lower polarity adherend and rough surface
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent modifies the chemical structure parameters of the carboxyl-containing monomer by specifying a particular structural formula with defined molecular weight range (500-5000) and structural characteristics. This parameter optimization enables the adhesive to achieve balanced adhesion to both higher and lower polarity adherends, resolving the contradiction between polarity-specific adhesion and broad adaptability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adhesive composition combines multiple components including the specifically structured carboxyl-containing monomer, other carboxyl-containing monomers, and conventional acrylic resin components. This composite formulation creates synergistic effects that improve adhesion to diverse substrates including lower polarity and rough surfaces while maintaining adhesion to higher polarity adherends

Inventive Principle:
Principle #40Composite materials

2Strength

If acrylic resin is used for adhesive composition, then the adhesiveness is improved, but the holding force and adhesiveness in high temperature/high humidity environment deteriorates

Engineering Contradiction:
ImproveadhesivenessVSAvoidholding force in high temperature/high humidity environment
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes the molecular weight parameter of the carboxyl-containing monomer to a specific range (500-5000) and defines its structural formula to balance polarity. This parameter control enhances the adhesive's resistance to environmental degradation, maintaining both initial adhesiveness and long-term holding force under high temperature and humidity conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The specifically structured carboxyl-containing monomer acts as a preventive measure against environmental degradation. Its optimized structure provides inherent resistance to moisture and heat before exposure occurs, cushioning the adhesive system against deterioration in high temperature/high humidity environments and preserving holding force

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If acrylic resin is used for adhesive composition, then the adhesiveness to adherend is improved, but the adhesion to poor adhesion adherend such as EPDM deteriorates

Engineering Contradiction:
Improveadhesiveness to adherendVSAvoidadhesion to poor adhesion adherend
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent specifies precise structural parameters for the carboxyl-containing monomer including molecular weight (500-5000) and structural formula characteristics. These parameter optimizations create an adhesive composition that effectively bonds to poor adhesion substrates like EPDM while maintaining adhesion to other adherend types

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adhesive composition integrates the specifically structured carboxyl-containing monomer with other complementary components. This composite approach creates multiple interaction mechanisms that enable effective adhesion to challenging substrates such as EPDM, overcoming the limitations of conventional acrylic resins

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 adhesive composition ensures strong and durable adhesion to higher and lower polarity adherends, including EPDM and rough surfaces, while maintaining adhesiveness and holding force in high temperature/high humidity environments, thus enhancing the performance of airtight waterproof adhesive tapes.

Implementation Method 1

an adhesive composition which has a higher adhesive strength to a higher polarity adherend, a lower polarity adherend, a poor adhesion adherend such as of ethylene propylene diene rubber (EPDM), and a rough adherend surface, and is excellent in holding force and adhesiveness even in a high temperature/high humidity environment

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11286323B2Adhesive composition, adhesive agent, adhesive tape, and airtight waterproof adhesive tape
Publication Date: 2022.03.29 MITSUBISHI CHEM CORP

AI summary

An adhesive composition contains an acrylic resin (A) obtained by copolymerizing a copolymerization formulation (a), the copolymerization formulation (a) including predetermined proportions of: (a1) at least one selected from the group consisting of a (meth)acrylate having a C1 to C3 alkyl group, t-butyl (meth)acrylate, a cyclic structure-containing monomer, and a C3 to C10 vinyl ester monomer; (a2) a (meth)acrylate having a C4 to C24 alkyl group (excluding t-butyl (meth)acrylate); (a3) a terminal carboxyl-containing monomer having a specific structure; and (a4) (meth)acrylic acid. The adhesive composition provides firm adhesion to a higher-polarity adherend, a lower-polarity adherend, a poor-adhesion adherend such as of ethylene propylene diene rubber (EPDM), and a rough surface, and is excellent in holding force and adhesiveness in a high-temperature/high-humidity environment, with reduced susceptibility to deterioration in adhesiveness over time.