Polyamide Graft Copolymer Adhesion to Elastomer

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Solution Overview

Problem

Existing composite parts made of thermoplastic and vulcanized elastomers often suffer from insufficient adhesive strength, leading to undesirable adhesion to metal molds and water pollution issues with current adhesion-promoting components.

Innovation Solution

Incorporating highly branched graft copolymers composed of polyamine and grafted polyamide chains into the polyamide molding compound, with a composition of at least 40% polyamide and a graft copolymer containing specific monomers, to enhance adhesion between polyamide and vulcanized elastomer sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional polyamide molding compounds are used with standard vulcanizing agents, then the composite can be produced, but the adhesive strength between polyamide and elastomer sections is insufficient

Engineering Contradiction:
Improveadhesive strengthVSAvoidbond reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the polyamide molding compound by incorporating graft copolymers with amino groups and reactive polyenes. This chemical parameter modification enables sufficient adhesive strength between polyamide and elastomer sections, resolving the contradiction between achieving strong bonds and maintaining reliable composite integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite molding compound by combining polyamide with specific graft copolymers (containing amino groups and reactive polyenes). This composite material approach allows the polyamide to achieve both structural integrity and enhanced adhesion to vulcanized elastomer, simultaneously improving strength and reliability.

Inventive Principle:
Principle #40Composite materials

2Strength

If reactive groups are added to the rubber compound to improve adhesion, then adhesive strength increases, but undesirable adhesion to the metal mold occurs

Engineering Contradiction:
Improveadhesive strengthVSAvoidmold adhesion
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention uses the polyamide matrix as an intermediary that contains both amino groups (for bonding to elastomer) and reactive polyenes (for bonding to mold). This intermediary structure allows controlled adhesion to the metal mold while preventing unwanted adhesion, and simultaneously provides strong bonding to the elastomer section.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention modifies the polyamide composition parameters by adding graft copolymers with specific functional groups (amino and reactive polyene). These parameter changes enable the polyamide to achieve balanced adhesion properties - strong bond to elastomer without undesirable adhesion to mold.

Inventive Principle:
Principle #35Parameter changes

3Strength

If TMPTMA is used as an adhesion-promoting component, then adhesion improves, but migration and water pollution occur

Engineering Contradiction:
Improveadhesive strengthVSAvoidmigration and water pollution
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention replaces TMPTMA with graft copolymers containing amino groups and reactive polyenes. This changes the chemical parameters of the adhesion-promoting component, eliminating migration and water pollution issues while maintaining strong adhesive bonds between polyamide and elastomer.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses polyamide-based adhesion promoters that are integrated into the matrix structure, replacing migratory additives like TMPTMA. The adhesion function is achieved through structural integration rather than migratory additives, eliminating environmental harm while maintaining bond strength.

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

4Strength

If polyamides with excess amino end groups are used to achieve good adhesion to carboxylated rubbers, then adhesive strength improves, but the use of common polyamide commercial grades with excess carboxyl end groups is limited

Engineering Contradiction:
Improveadhesive strengthVSAvoidpolyamide grade compatibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The invention creates a composite polyamide molding compound that incorporates graft copolymers with amino groups and reactive polyenes. This composite approach allows the use of common polyamide commercial grades (with excess carboxyl end groups) while achieving good adhesion to carboxylated rubbers through the grafted amino groups.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention modifies the polyamide composition by adding graft copolymers, changing the end group balance parameters. This allows common polyamide grades with carboxyl end groups to be used while achieving amino group functionality for adhesion to carboxylated rubbers.

Inventive Principle:
Principle #35Parameter changes

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

Significantly improves the adhesive strength between polyamide and vulcanized elastomer sections, preventing undesirable adhesion to metal molds and reducing water pollution, while allowing the use of common polyamide commercial grades with excess carboxyl end groups.

Implementation Method 1

the polyamide molding compound comprises at least 40% by weight of a mixture of polyamide and graft copolymer... significantly improves the adhesive strength between polyamide and vulcanized elastomer sections

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

A mixture of dicumyl peroxide and N,N'-m-phenylenedimaleimide is added to the rubber as a vulcanizing agent

Methodology Applied
Scientific EffectVulcanization: Chemical Bonding

Data Source

PatentEP2566691B1Composite formed from a polyamide moulding composition and a vulcanized elastomer
Publication Date: 2015.03.04 EVONIK OPERATIONS GMBH

AI summary

In a composite component assembled from at least one component piece comprising a polyamide moulding composition with at least one component piece comprising a vulcanized elastomer, the polyamide moulding composition comprises at least 40% by weight of a mixture of the following constituents: a) 60 to 99 parts by weight of polyamide and b) 1 to 40 parts by weight of a graft copolymer obtainable using the following monomers: a) 0.5% to 25% by weight, based on the graft copolymer, of a polyamine having at least 4 nitrogen atoms and also ß) 75% to 99.5% by weight, based on the graft copolymer, of polyamide-forming monomers selected from lactams, ?-amino carboxylic acids and/or equimolar combinations of diamine and dicarboxylic acid, wherein the parts by weight of a) and b) sum to 100. The presence of the graft copolymer effectuates improved adherence between the component pieces.