“Cohesive” metal bonding –Examples of structural bonding

with unprepared metals

LORD Germany GmbHDipl. Ing. Uwe Manert

Bad Nauheim, 17 – 19 April 2012

Agenda

Scoping / Adhesive selection

2K Acrylic adhesives technologies

Application overview

Summary

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LORD Corporation: An Overview

A global technology leader providing valuable expertise in:

Adhesives and coatings

Vibration, motion and noise control

Magnetically responsive technologies

3

Quick facts about LORD

More than 2,600 employeesPrivately-held companyMore than $700MM in annual salesWorld headquarters in Cary, NC17 manufacturing facilities in nine countries90 strategically located sales and support centers worldwide

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SELECTION: METAL BONDING ADHESIVES

Metal Scope:

1. Step – select metals:

SteelAluminumStainless Steel

2. Step - surface conditions:

Steel – bare or zinc coatedAluminum – bare or anodizedStainless Steel – all alloys

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2K ACRYLICS: CHEMISTRY

Base: Methylmethacrylate (MMA)

Accelerator: Peroxide (BPO)

Cure: radical polymerization

Remark: even gaining a thermoplastic material special formulation can be used prior to powder coating of metal assemblies!

LORD 663/6GB with a Tg of approx 100°C with RT cure!

Acrylic Peroxide

Thermoplast

+ =

+ heat!

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2K ACRYLICS: CHEMISTRY

Functional Additives:

Rubber: toughener (for use below -40°C)

Primer: adhesion promoter

Filler: viscosity adjustmenthigh temperature performance

Catalyst: start reaction

Acrylic Peroxide

Thermoplast

+ =

+ heat!

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2K ACRYLICS: CURE & PERFORMANCE

Example of cure vs. Time for LORD acrylics

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2K ACRYLICS: CURE & PERFORMANCE

Environmental stability of LORD acrylics MPa

ACRYLIC GROUPING

Reversible / Physically curing:

Hot MeltSolvent Based

Dispersion

By Reactivity

Uncured:Pressure Sensitive

(PSA)

Irreversible / Chemically curing:

2 Component (2K)1 Component (1K) / heat

1 Component (1K) / moisture

2K Acrylics are a mixture – due to the solvent based character they are able to absorb oil during curing!

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ACRYLIC GROUPING

Hot Melt

N/mm²

Cure time

PSA

1K Sealants

1Kanaerobic

2K cold cure

1K / 2K heat cure

Solventbased

By Cure time vs. Strength

seconds Hours / days

1

10

30

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ACRYLIC GROUPING

N/mm²

Elongation at break

Hot Melt

PSA1K Sealants

Solventbased

By Elongation vs. Strength

1 10 100 500 1000

2K PU

1

10

20

30

2K Epoxy

2K LORD

HP Acrylic

Rubber

LORD ACRYLIC APPLICATIONS

Versilok® - Automotive Hem Flange Bonding

Cures at room temperature

Deformation in the oven

e.g. LORD Versilok® 262/254 for steel to aluminum

No deformation after heat cycle

LORD® - Automotive Truck Floor Assembly

Bonding of bare aluminium after dry wipe:LORD 410/19GB

Customized test procedure 3 days after cure: 4 tons +

LORD ACRYLIC APPLICATIONS

LORD® - Solar bonding (CSP)

Trough installation: Field appliedAlu to Steel (MS)LORD 410/19GBService Life: 25 years +

LORD ACRYLIC APPLICATIONS

LORD® - Storage and more

SUMMARY

1. SmellWorkspace has to be fitted with ventilation for fumes heavier than air!

2. Shelf lifeLimited shelf life (9 month) requires planning

3. StorageStorage temperatures above 25°C have to be avoided!

Cohesive bonding without surface preparation?

SUMMARY

Acrylic adhesives can clean and prime on their own if proper recipe is used!

Remind this if you switch to a different chemistry!