Contents


                     Preface    XV


                     List ofContributors   XVII



         1           Adhesive Bonding as a joining Technique    1

         2           The Historical Development of Adhesive Bonding         5

         3           Adhesion    11
         3.1         Introduction 11
         3.2         Classical Adhesion Theories 14
         3.2.1       Polarization Theory 17
         3.2.2       Diffusion Theory 20
         3.2.3       Chemical Reactions 21
         3.3         Adhesion in Real Systems 24
         3.3.1       Gold 25
         3.3.2       Polyethylene and Polypropylene 25
         3.3.3       Glass 26
         3.4         New Concepts in the Field of Adhesion     26
         3.5         Conclusions 28

         4           Survey and Classification of Adhesives and Primers         29
         4.1         Noncuring (Pressure-Sensitive) Adhesives       29
         4.2         Physically Setting Adhesives 33
         4.2.1       Contact Adhesives 33
         4.2.2       Plastisol Adhesives 34
         4.2.3       Hot-Melt Adhesives 34
         4.3         Chemically Setting Adhesives 35
         4.3.1       Two-Part Adhesives 35
         4.3.2       Hot-Setting, One-Part Adhesives 36
         4.3.3       Cold-Setting, One-Part Adhesives 36




VI   Contents

     4.3.4      Microencapsulated Adhesives 37
     4.4        Primers 37
     4.5        General Handling Instructions 38

     5          Chemistry and Properties of Adhesives and Primers   39
     5.1        Pressure-Sensitive Adhesives (PSAs) 40
     5.1.1      Introduction 40
     5.1.2      Chemistry of Pressure-Sensitive Adhesives 40
     5.1.3      Physical Properties of Pressure-Sensitive Adhesives 43
     5.1.4      Properties of Pressure-Sensitive Adhesives as a Function of
                Temperature 44
     5.1.5      Tack 45
     5.1.6      Peel Resistance 45
     5.1.7      Creep 45
     5.1.8      Formulations of PSAs 46
     5.1.8.1    T ypicalFormulationofNaturalRubber-BasedPSAs 46
     5.1.8.2    Typical Formulation of Block Copolymer PSAs 46
     5.1.8.3    Typical Formulation of Acrylate-Based PSAs 47
     5.2        Contact Adhesives 47
     5.2.1      Composition of Contact Adhesives 47
     5.2.2      Properties and Fields of Application of Contact Adhesives 48
     5.3        Hot Melts 49
     5.3.1      Thermoplastic Hot Melts 50
     5.3.2      Hot-Seal Adhesives 51
     5.3.3      Plastisols 51
     5.3.4      Self-Bonding Varnishes 52
     5.3.5      Polyurethane-Based Reactive Hot Melts 52
     5.3.6      Epoxy Resin-Based Reactive Hot Melts 52
     5.3.7      Trends in Hot-Melt Technology 53
     5.4        Phenolic Resin Adhesives 53
     5.4.1      Chemistry of Phenolic Resins 53
     5.4.2      Formulation of Phenolic Resin Adhesives 56
     5.4.3      Behavior and Applications of Phenolic Resin Adhesives 57
     5.5        Epoxy Resin Adhesives 58
     5.5.1      Chemistry of Epoxy Resin Adhesives 58
     5.5.2      Reactions of Epoxy Resins 59
     5.5.3      Properties of Epoxy Resin Adhesives 60
     5.5.4      Formulations of Epoxy Resin Adhesives 63
     5.5.4.1    Epoxy Resins 63
     5.5.4.2    Crosslinking Agents 64
     5.5.4.3    H ardeners 64
     5.5.4.4    Flexibilizers and Additives That Improve Impact Toughness 64
     5.5.4.5    Fillers and Thixotroping Agents 65
     5.5.4.6    Further Additives 65
     5.5.4.7    Typical Epoxy-Resin Adhesive Formulations 65
                                                                    Contents   V II


5.6       Polyurethane Adhesives 66
5.6.1     Chemistry of Polyurethanes 66
5.6.2     Raw Materials 67
5.6.2.1   Isocyanates 67
5.6.2.2   Polyols 68
5.6.2.3   Catalysts 69
5.6.3     Structure and Properties of Polyurethane Adhesives 69
5.6.3.1   One-Part Polyurethane Adhesives 69
5.6.3.2   Two-Part Polyurethane Adhesives 70
5.6.4     Formulations of Polyurethane Adhesives 70
5.7       Acrylate Adhesives 71
5.7.1     Physically Setting Acrylates 71
5.7.1.1   Solvent-Containing Acrylates 71
5.7.1.2   Dispersion Acrylates 71
5.7.1.3   Acrylate-Based Contact Adhesives 71
5.7.2     Chemically Setting Acrylates 71
5.7.2.1   Monomers 73
5.7.2.2   Two-Part Acrylates/Methacrylates 74
5.7.2.3   One-Part Acrylates/Methacrylates 75
5.7.2.4   Examples of Application 75
5.7.2.5   Anaerobic Acrylates 76
5.7.2.6   UV-Setting Acrylates 77
5.7.2.7   Cyanoacrylate Adhesives 83
5.7.3     Formulations of Acrylate Adhesives 84
5.7.3.1   Formulation of a Two-Part Acrylate 'No Mix' Adhesive 84
5.7.3.2   Formulations of UV-Setting Acrylate Adhesives 84
5.7.3.3   Formulations of Cyanoacrylate Adhesives 85
5.8       Silicones 85
5.8.1     One-Part Silicone Adhesives 85
5.8.2     Two-Part Silicone Adhesives 86
5.8.2.1   Condensation Crosslinking 86
5.8.2.2   Addition Crosslinking 87
5.9       Natural Adhesives 88
5.9.1     Introduction 88
5.9.2     Natural Raw Materials 89
5.9.3     Modern Adhesives Based on Natural Raw Materials 91
5.9.3.1   Glutine Glue 92
5.9.3.2   Casein Glues 92
5.9.3.3   Dextrin Glues 93
5.9.3.4   Natural Material-Based Pressure-Sensitive Adhesives 93
5.9.4     Future Trends 94
5.10      Chemistry of Primers and Adhesion Promoters 94
5.10.1    Primers 95
5.10.2    Adhesion Promoters 96
5.11      Fillers 99
VIII Contents

     6          Design, Production and Quality Assurance of Adhesive
                Bonded Joints 101
     6.1        Design and Dimensioning 101
     6.1.1      Interaction of Polymer Behavior and State of Srress   101
     6.1.2      Design of Adhesive Bonded Joints 103
     6.1.3      Dimensioning of Adhesive Bonded Joints 104
     6.2        Surface Preparation 108
     6.2.1      Mechanical Surface Preparation Methods 109
     6.2.1.1    Grit Blasting 109
     6.2.1.2    Grinding 110
     6.2.1.3    Brushing 110
     6.2.2      Chemical Surface Preparation Techniques 111
     6.2.3      Physical Surface Preparation Techniques 111
     6.2.3.1    Flame Treatment 111
     6.2.3.2    Microplasma Treatment 111
     6.2.3.3    Atmospheric Plasma Treatment 112
     6.2.3.4    Low-Pressure Plasma Treatment 112
     6.2.3.5    Corona Treatment 112
     6.2.4      The Preconditions of Adhesion 112
     6.2.5      Protection of Prepared Surfaces 114
     6.3        Application ofthe Adhesive 115
     6.3.1      Processing of Adhesives 115
     6.3.1.1    Processing of Two-Part Adhesive Systems 115
     6.3.1.2    Processing of One-Part Adhesive Systems 119
     6.3.1.3    Hot-Melt Adhesives 121
     6.3.1.4    Film Adhesives 121
     6.3.1.5    Hybrid Bonding 122
     6.3.2      Quality Assurance 123

     7          Adhesives and Adhesive Joints: Test Methods and Properties   125
     7.1        Adhesive Bulk Properties 126
     7.1.1      Stress-Strain Analysis of Bulk Specimens 126
     7.1.2      Determination of Tg by Dynamic Mechanical Analysis or
                Differential Scanning Calorimetry 127
     7.1.3      Coefficient of Thermal Expansion (CTE) 128
     7.1.4      Temperature Resistance by Thermogravimetry 128
     7.2        Test Categories by Type of Mechanical Srress 128
     7.2.1      Tensile Srress (e.g. Butt Joints) 128
     7.2.2      Shear Srress (e.g. Single Lap Shear Specimen) 130
     7.2.3      Cleavage (e.g. Wedge Test) 132
     7.2.4      Fracture Resistance 133
     7.2.5      Wedge Test 133
     7.2.6      Peel Test 134
     7.3        Test Categories by Duration and Load Rate 137
     7.3.1      Long-Term Statte Tests (e.g. Creep Experiments Under Dead Load)    137
                                                                       Contents   IX

7.3.2     Impact Tests (e.g. Impact Wedge Test to Evaluate Crash
          Performance) 138
7.3.3     Cydic Loading (e.g. Fatigue Tests) 139
7.4       Assessment ofDurability and Service Life of Adhesive Joints 139
7.5       Tests Related to Storage and Handling of Adhesives 143
7.5.1     Determination of Words and Phrases Relating to the
          Product Life 143
7.5.2     Open Time and Working Life 143
7.5.3     Extrudability 144
7.5.4     Sagging 144
7.5.5     Volatile Organic Compound (VOC) Emissions 144
7.6       Nondestructive Testing Methods 145
7.6.1     Visual Techniques 146
7.6.2     Radiographic Techniques 146
7.6.3     Magneü'c, Electrical and Chemical Techniques 146
7.6.4     Mechanical Vibration 147
7.6.4.1   Impulse-Induced Resonance 147
7.6.4.2   Pulse Echo 148
7.6.4.3   Through-Transmission Sound Testing 149
7.6.5     Thermal Methods 149
7.6.5.1   Optical and Ultrasonic Lockin Thermography 149
7.6.5.2   Ultrasound Burst Phase Thermography 151
7.6.5.3   Excitation Mechanisms for Active Thermography 153
7.6.6     Assessment of Nondestructive Testing Methods 155
7.7       Applications of Test Methods in Structural Adhesive Bonding 156
7.7.1     Tensile Shear Strength Under Short-Term Loading 157
7.7.2     Tensile Shear Strength Under Long-Term Statte and Alternating
          Loading 162
7.7.3     Peel Strength 164
7.7.4     Impact Behavior 165
7.7.5     Durabilityof Bonded Joints 366
7.7.6     Adhesive Bonding of Aluminum 168
7.7.7     Adhesive Bonding of Steel 183
7.7.8     Adhesive Bonding ofGlass 388
7.7.9     Adhesive Bonding of Polymer Materials 393
7.8       Experiences and Leaming from Damage Cases 191
7.8.1     Delamination of Bonded Rotor Blade Pockets 393
7.8.2     Total Separation ofa Rotor Blade Profile 194
7.8.3     Bond-Iine Corrosion in Wing Honeycombs 396
7.8.4     Delamination of the Outer Cover Sheet of Tail Units of Aircraft 197
7.8.5     Temperature-Induced Damage on a Tail Rotor Blade 399
7.8.6     Temperature-Induced Delamination ofa Bonded Glass Fiber
          Patch 200
7.8.7     Incorrect Design of Bonded Filter Elements 203
7.8.8     Deficiencies of the Peel Ply Treatment 202
X   Contents

    8          Adhesive Bonding Technology: Fields of Application   205
    8.1        Introduction 205
    8.2        Transportation 206
    8.2.1      Aircraft Manufacture 207
    8.2.1.1    Historical Development 209
    8.2.1.2    Advantages of Bonding in Aircraft Manufacture 233
    8.2.1.3    Adhesives Used in Aircraft Manufacture 236
    8.2.1.4    Surface Preparation 217
    8.2.1.5    Bonding Techniques 218
    8.2.1.6    Quality Control of Bonding in Aircraft Manufacture 218
    8.2.1.7    Condusions 219
    8.2.2      The Automotive Industry 220
    8.2.2.1    Bonding in Passenger Car Bodywork Construction 223
    8.2.3      Bonding in Rail Vehide Manufacture 234
    8.2.4      Shipbuilding 235
    8.3        Building Industry 237
    8.3.1      Adhesives for the Bonding of Surfaces 237
    8.3.1.1    Adhesive Mortars for Tiling 237
    8.3.1.2    Floor-Covering Adhesives 238
    8.3.2      Adhesive Anchors in the Building and Construction Industry 238
    8.3.2.1    Adhesive Anchor Systems 238
    8.3.2.2    Adhesives 240
    8.3.3      Building Reinforcement by Means of Bonded Surface
               Reinforcement 241
    8.3.4      Structural Bonding in Structural Steel and Facade Engineering 243
    8.4        Wooden Constructions 243
    8.4.1      Introduction 243
    8.4.2      The Structure of Wood 245
    8.4.2.1    The Molecular Structure of Wood 245
    8.4.2.2    The Macroscopic Structure of Wood 246
    8.4.3      Consequences 246
    8.4.3.1    Strength, Swelling and Shrinking 246
    8.4.4      Adhesive-Wood Interphase 247
    8.4.5      Adhesive Systems 247
    8.4.6      Adhesives Based on Renewable Resources 248
    8.4.7       Synthetic Wood Adhesives 249
    8.4.7.1    Physically Setting Systems 249
    8.4.7.2    Chemically Setting Adhesives 249
    8.4.7.3    Adhesion Promoters (Primers) 253
    8.4.8      Wood Composites 251
    8.4.9      The Supreme Disripüne: Laminated Wood Constructions
                (Civil Engineering Using Wood as Building Material) 253
    8.4.9.1    Development 253
    8.4.9.2    Laminated Wood Constructions Today 253
    8.4.10      Prefabricated Elements 255
                                                                       Contents   XI

8.4.11     Prospects of Wood Constructions 257
8.5        Paper and Packaging Industry 257
8.5.1      Introduction 257
8.5.2      Manufacture of Packaging Materials 258
8.5.2.1    Corrugated Board and Paperboard Containers 258
8.5.2.2    Lamination 259
8.5.2.3    Folder Gluer 259
8.5.2.4    Folding Cartons 260
8.5.2.5    Flexible Packages 260
8.5.2.6    Bags, Pouches and Sacks 263
8.5.3      The Setting-Up and Closing of Trays and Boxes 264
8.5.3.1    Setting-Up a Tray 264
8.5.3.2    Carton Closing 264
8.5.4      Pallet Securing 267
8.5.5      Labeling 269
8.5.5.1    Pressure-Sensitive Labels 269
8.5.5.2    Inline Labeling 270
8.5.5.3    Tamper-Evident Bottle Closures 273
8.5.5.4    Membrane Bonding 274
8.5.6      Cigarette Production 274
8.5.7      Manufacture of Tissue Paper Products 274
8.5.7.1    Core Winding 275
8.5.7.2    Lamination 276
8.5.7.3    Pick-Up Adhesives 277
8.5.7.4    Tau Tie Adhesives 277
8.5.8      Graphic Products 278
8.5.8.1    Unsewn Binding 278
8.5.8.2    Unsewn Binding with Dispersion Adhesives 279
8.5.8.3    Unsewn Binding with Hot Melts 279
8.5.8.4    Unsewn Binding with Reactive Polyurethane Hot Melts   280
8.5.8.5    Multilayer Unsewn Binding 282
8.5.8.6    Side Gluing 283
8.5.8.7    Backgluing of Thread-Sewn Book Blocks 284
8.5.8.8    Book Manufacture 284
8.5.8.9    MaMng the Case 285
8.5.8.10   Casing-In 285
8.5.8.11   Fold Gluing 286
8.5.9      Envelopes and Advertising Mail 286
8.5.10     Reuse and Recyding of Paper and Packages 287
8.5.10.1   Reuse 287
8.5.10.2   Recyding 288
8.5.10.3   Recycling of Paper Products 288
8.5.10.4   Recyding ofPlastk Packaging 293
8.5.10.5   Compostable Products 291
8.5.11     Regulations Stipulated by Law 292
XII   Contents

      8.5.12     Perspectives 292
      8.6        Small-Scale Industries and Handicraft Trades 293
      8.6.1      Joining 293
      8.6.1.1    Structural Adhesives 294
      8.6.1.2    Cyanoacrylate Adhesives 295
      8.6.1.3    Postcuring Hot Melts 296
      8.6.1.4    Hot-Melt Adhesive Systems 296
      8.6.1.5    Aerosol Adhesives 297
      8.6.1.6    Dispersion Adhesives 297
      8.6.1.7    Solvent-Based Adhesives 298
      8.6.1.8    High-Performance Acrylic PSA Tapes 298
      8.6.1.9    Redosable Fasteners 300
      8.6.1.10   Screen-Printable Adhesives 301
      8.6.2      Protecting, Splicing and Masking 301
      8.6.3      Damping 304
      8.6.4      Labeling, Marking and Coding 305
      8.7        Electronics Industry 307
      8.7.1      Thermally Conductive Adhesives 307
      8.7.2      Electrically Conductive Adhesives 308
      8.7.3      Underffll Materials 310
      8.7.4      Functional PSA Tapes 310
      8.7.5      Spacers 311
      8.7.6      Labeling 311
      8.8        Optical Industry 312
      8.8.1      General Requirements for Adhesives in Optical Industry 312
      8.8.2      Optical Adhesives for the Temporary Fixture of Optical
                 Elements 333
      8.8.3      Optical Cementing 334
      8.8.4      Bonding Optical Elements to Mounts 315
      8.9        Mechanical Engineering and Process Equipment Construction 316
      8.9.1      Mechanical Engineering 316
      8.9.2      Domestic Appliance Industry 317
      8.9.3      Manufacture of Internal Combustion Engines and Transmission
                 Manufacturing 317
      8.9.4      Stainless Steel Structures 339
      8.10       Textile Industry 320
      8.10.1     T he Early History of Fabric-Reinforced Rubber Materials 320
      8.10.2     How Textile Fibers Contribute to the Iiving Standards of the
                 Industrial World 321
      8.10.2.1   Technical Textiles 322
      8.10.2.2   Textiles as Rubber Reinforcements 322
      8.10.3     General Properties of Elastomers (Rubber) 323
      8.10.4     Treatment of Textiles for Rubber Reinforcement 324
      8.10.4.1   Reinforcement Fibers 324
      8.10.4.2   Adhesive Systems Used to Treat Textiles 324
                                                                    Contents   XIII

8.10.4.3   Effect of the Fiber Type on the Adhesive System 326
8.10.4.4   Direct Adhesion Through Addition of the Adhesion Promoter
           to the Rubber Mixture 328
8.10.5     Adhesion Mechanisms 328
8.10.6     Agingof RFL-Dipped Textiles 330
8.11       Footwear Industry 332
8.12       Road and Highway Engineering 333
8.12.1     Traffic Signs 334
8.12.2     Pavement Markings 335
8.12.3     Iicense Plates 337
8.13       Surface Design 337
8.13.1     Surface Design and Surface Protection 337
8.13.2     Fleet Graphics 338
8.13.3     Public Transport Advertising 338
8.13.4     Building and Floor Graphics 340
8.14       Tamper-Indicating Labels 343
8.15       Medical Sector 343
8.15.1     Medical Devices with Short-Term, Superfidal Body Contact 343
8.15.2     Medical Devices with Several (up to 30) Days Body Contact 343
8.15.3     Medical Devices with Long-Term (Over 30 Days) Body Contact 344
8.16       Adhesion in Nature 346
8.16.1     Design Principles of Biological Attachment Devices 346
8.16.2     Gluing Under Water 347
8.16.2.1   Byssus Adhesion in Mollusks 348
8.16.2.2   TubeFeetofStarfish 351
8.16.2.3   Adhesion in Barnacles 353
8.16.2.4   Temporary Adhesion in Cladoceran Crustaceans 354
8.16.2.5   Adhesion in Larval Fish and Ascidians 354
8.16.3     Adhesion in Terrestrial Insects 354
8.16.3.1   Permanent Adhesion in Insects and Spiders 354
8.16.4     Adhesion in Plants 355
8.16.5     Surface-Replicating Mechanism Based on Growth 356
8.17       Iittle-Known Applications 356
8.17.1     Foils for the Rotors of Wind Turbines 356
8.17.1.1   Erosion-Protection 357
8.17.1.2   Iightning Protection and Performance Enhancement 358
8.17.2     Adhesive Elastomer Composites 358
8.17.3     Light Bulbs 359
8.17.4     Bonding in Art, Jewelry Making and Archeology 361
8.17.4.1   Art 363
8.17.4.2   Jewelry Making 363
8.17.4.3   Archeology 364
8.17.5     Removable Adhesive Joints 365
8.17.5.1   Commercially Available Removable Adhesive Systems 365
8.17.5.2   High-Strength Removable Adhesives 367
XIV   Contents

                 Perspectives 371
      9
      9.1        Economic Trends 371
                 Technical Trends 371
      9.2

                 Appendix 375

                 References   393

                 Index 403