Preface ......................................................... v
Chapter 1 Introduction to Coatings Technology
1.1 Coating markets and market prospects ....................... 2
1.2 UV coating markets and market prospects .................... 4
1.3 UV technology and applications . ........................... 7
1.4 Advantages and drawbacks of UV coatings ................... 11
1.5 Eco-efficiency ............................................ 13
1.6 Driving forces of UV technology ........................... 14
1.7 Current R&D topics and trends in UV technology ............ 15
1.8 Perspectives .............................................. 16
References ..................................................... 17
Chapter 2 The UV Curing Process
2.1 Application (property requirements) ....................... 20
2.2 Chemistry (photochemical process) ......................... 21
2.2.1 Photoinduced curing chemistry ...................... 22
2.2.2 Kinetics ........................................... 26
2.2.3 Frontal polymerization ............................. 32
2.2.4 Heat of polymerization ............................. 32
2.2.5 Evaluation of cure extent .......................... 33
2.3 Equipment (for UV curing process) ......................... 37
2.3.1 Coating application processes ...................... 37
2.3.2 Exposure process ................................... 38
2.3.3 UV line equipment .................................. 44
2.3.4 Exposure parameter measurement ..................... 48
2.3.5 UV coating line examples ........................... 56
2.3.6 Equipment suppliers ................................ 58
References ................................................ 59
Chapter 3 Network Formation and Characterization
3.1 Film formation ............................................ 65
3.2 Network formation ......................................... 66
3.3 Monitoring film formation and curing ...................... 73
3.4 Network characterization .................................. 74
3.4.1 Test methods for analyzing physical properties ..... 75
3.4.2 Chemical characterization .......................... 90
References ................................................ 92
Chapter 4 Raw Materials
4.1 Radical polymerization systems ............................ 95
4.1.1 Standard resins .................................... 95
4.1.2 Specialty resins .................................. 103
4.1.3 Reactive diluents ................................. 111
4.1.4 Radical photoinitiators ........................... 114
4.2 Cationically-curable systems ............................. 120
4.2.1 Cationically curable resins and monomers .......... 120
4.2.2 Cationic photoinitiators .......................... 121
4.2.3 Photosensitization of cationic
photopolymerisation ............................... 122
4.3 Thiol-ENE systems ........................................ 123
4.4 Coating additives ........................................ 125
4.5 Characterization of raw materials ........................ 126
4.5.1 Viscosity ......................................... 126
4.5.2 Chemical characterization ......................... 127
4.5.3 Spectroscopic characterization .................... 128
4.5.4 Chromatographic characterization .................. 130
4.5.5 Thermal analysis .................................. 130
4.5.6 Particle size measurement ......................... 131
4.6 Selection of raw materials ............................... 131
4.6.1 Raw materials for exterior applications ........... 131
4.7 Raw material suppliers ................................... 135
References ............................................... 136
Chapter 5 Formulations
5.1 Formulations for wood coatings ............................141
5.1.1 Industrial parquet coating ........................ 142
5.1.2 Adhesion primer (to the wooden substrate) ......... 142
5.2 Formulations for graphic inks ............................ 144
5.2.1 Printing inks (UV offset, UV flexo and UV screen
inks) ............................................. 145
5.2.2 Formulation for overprint varnishes (OPV) ......... 146
5.3 Specialty formulations (for glass, polycarbonate,
metal) ................................................... 148
5.4 Formulation screening for new applications ............... 149
5.5 Increasing efficiency in formulation screening:
High-throughput screening (HTS) .......................... 153
References ............................................... 159
Chapter 6 Structure-Property Relationships
6.1 Effect of crosslinking on mechanical properties .......... 162
6.1.1 Cure conversion and glass transition temperature .. 164
6.1.2 Hardness and flexibility as a function of Tg ...... 166
6.1.3 Influence of Mc (molecular weight between
crosslinks) ....................................... 169
6.2 Effect of crosslinking on coating properties ............. 172
References ............................................... 177
Chapter 7 Tackling the Drawbacks of UV Systems
7.1 Oxygen inhibition ........................................ 179
7.1.1 Physical methods .................................. 181
7.1.2 Chemical methods .................................. 183
7.1.3 Conclusions ....................................... 184
7.2 Shadow areas ............................................. 185
7.3 Initial photoyellowing ................................... 186
7.3.1 Conclusions ....................................... 192
References ............................................... 193
Chapter 8 Classical Applications
8.1 On wooden surfaces ....................................... 195
8.2 In graphic arts industry ................................. 199
8.2.1 Imaging applications .............................. 199
8.2.2 Inks .............................................. 202
8.2.3 Overprint varnishes (OVP) ......................... 204
References ............................................... 204
Chapter 9 Recent Developments
9.1 Chemistry related developments ........................... 206
9.1.1 Solvent-borne UV coatings ......................... 206
9.1.2 Water-based UV coatings ........................... 206
9.1.3 UV powder coatings ................................ 213
9.1.4 Dual cure coatings (UV and thermal) ............... 218
9.1.5 UV-curable nanocoatings/nanocomposites ............ 223
9.1.6 Weathering resistance of UV-cured acrylics ........ 227
9.2 Process related developments ............................. 238
9.2.1 UV curing under inert (nitrogen, carbon dioxide)
atmosphere ........................................ 238
9.2.2 Larolux®: UV inert curing with tanning lamps ...... 244
9.2.3 UV curing of pigmented systems .................... 246
9.2.4 UV plasma curing .................................. 246
References ............................................... 249
Chapter 10 New Applications
10.1 Automotive applications .................................. 252
10.1.1 Suitability of UV coatings for automotive
applications ...................................... 254
10.1.2 UV-curable clear coats (head lamps, reflectors,
alu wheels) ....................................... 256
10.1.3 UV-curable primer/sealer (eco-efficiency) ......... 258
10.1.4 UV-curable coatings for car refinish .............. 264
10.1.5 Scratch resistant coatings for automotive
applications ...................................... 266
10.1.6 Plastic applications in automotive ................ 276
10.2 Industrial applications .................................. 277
10.2.1 UV-curable coatings for hard topcoats on plastic .. 277
10.2.2 UV-curing of highly flexible coatings ............. 277
10.2.3 Coil coatings ..................................... 278
10.2.4 Adhesives ......................................... 281
10.2.5 UV inkjet ......................................... 284
10.2.6 UV systems for dental applications ................ 285
10.2.7 Furniture foil coatings ........................... 286
10.3 Film coating instead of painting: An innovative concept .. 286
References ............................................... 289
Chapter 11 Health, Safety and Environment
11.1 Safe handling of acrylates (labelling guide) ............. 292
11.2 Principles for safe use of UV coatings and inks:
UV protocol .............................................. 294
11.3 UVITECH (Risk assessment of UV curing in printing
industry) ................................................ 295
11.4 Reduction of emissions (VOC regulation) .................. 296
11.5 Registration, evaluation and authorization of chemicals
(REACH) .................................................. 297
11.6 UV coated materials for food contact ..................... 300
11.7 Concept of best available technique (BAT) ................ 301
References ............................................... 301
Subject Index ................................................. 303
|
