Table of Contents
Preface v
1 Introduction to polyurethanes 1
1.1 An overview 1
1.2 Chemistry of polyurethanes in brief 2
1.3 Some important polyurethanes 3
1.3.1 Flexible foams 3
1.3.2 Rigid polyurethane foams 3
1.3.3 Coatings, adhesives, sealants and elastomers 4
1.3.4 Thermoplastic polyurethane 4
1.3.5 Reaction injection moulding 4
1.3.6 Binders 4
1.3.7 Waterborne polyurethane dispersions 5
1.4 Some polyurethane applications 5
1.4.1 Apparel 5
1.4.2 Appliances 5
1.4.3 Automotive 5
1.4.4 Building construction 6
1.4.5 Electronics 6
1.4.6 Flooring 6
1.4.7 Furnishings 7
1.4.8 Medical 7
1.4.9 Packaging 7
1.4.10 Speciality mouldings 7
Bibliography 8
2 Types of polyurethanes 9
2.1 Flexible foams 9
2.1.1 Conventional flexible foams 10
2.1.2 High-resilience foams 10
2.1.3 Viscoelastic foams 11
2.2 Spray foams 12
2.2.1 High-pressure two-component PU spray foams 12
2.3 Semi-rigid foams 13
2.4 Rigid foams 14
2.4.1 Energy efficiency 14
2.4.2 High performance 14
2.5 Microcellular polyurethane foams 15
2.5.1 Microcellular polyurethane elastomer 16
2.5.2 Microcellular urethanes 16
2.6 Thermoplastic polyurethane 17
2.7 Filled foams 18
2.8 Composite foams 19
2.9 Structural foams 20
2.10 Foams for comfort 21
2.10.1 Latex foam 21
2.10.2 Polyurethane foam (Open cell) 21
2.10.3 Memory foam 22
2.10.4 Natural memory foam 22
2.11 Integral skin foams 23
Bibliography 24
3 Two-component systems 25
3.1 Introduction 25
3.2 The concept of two-component systems 25
3.3 Systems used for general applications 27
3.3.1 Systems for producing flexible foam blocks 27
3.3.2 System for high-resilience foams 28
3.3.3 Spray foam systems 29
3.3.4 Systems for integral skin foam moulding 30
3.3.5 System for automobile applications 30
3.3.6 Systems for insulation of pipe joints 31
3.3.7 Systems for structural and casting foams 32
3.3.8 Systems for thermoplastic foams 33
3.3.9 Systems for protective coatings 34
3.3.10 Systems for memory foam (viscoelastic) 35
3.4 Solvent-based two-component polyurethane systems 36
3.4.1 Solutions for superior adhesion 36
3.4.2 Solvent-based coatings 37
3.4.3 Solvent-based high-gloss surface coatings 38
3.5 Waterborne two-component polyurethane systems 38
3.6 Some additional polyurethane systems for speciality applications 40
3.6.1 Integral skin foam two-component polyurethane system 40
3.6.2 Two-component polyurethane taxidermy moulding foam 41
3.6.3 Two-component polyurethane systems for rapid prototyping 42
3.6.4 Hand-pourable polyurethane viscoelastic flexible foam 44
3.6.5 Microcellutar polyurethane elastomers for auto components 44
3.6.6 Protective coating systems for the mining sector 45
3.6.7 Two-component polyurethane system for tabletop protection 45
3.6.8 Polyurethane system for marine applications 46
3.6.9 Two-component polyurethane system for block foam 46
3.6.10 Two-component systems polyurethane systems for rigid moulding foam 47
3.6.11 Two-component systems for high-yield packaging foam 48
Bibliography 49
4 Basic raw materials for polyurethanes 51
4.1 Raw materials 51
4.1.1 Polyols 51
4.1.2 Isocyanates 52
4.1.3 Water (primary blowing agent) 52
4.1.4 Auxiliary blowing agents 53
4.1.5 Silicone surfactants 53
4.1.6 Catalyst systems 53
4.1.7 Basic additives 54
4.2 Packaging for two-component systems 56
4.3 Non-traditional biomass fillers 57
4.4 Handling raw materials safely in brief 59
4.5 Managing spills 60
4.6 Raw material storage 60
Bibliography 61
5 Mould designs 63
5.1 Introduction 63
5.2 Design parameters 64
5.3 High-tech mould designing for integral skin products 65
5.4 Hand-mixed productions 66
5.4.1 Mould design for hand-mixed pouring 66
5.4.2 Moulds for larger rigid foam blocks for taxidermy 69
5.4.3 Moulds for circular flexible foam blocks 70
5.4.4 Moulds for high resilience PUR foam mattresses 71
5.4.5 Moulds for viscoelastic (memory foam) mattresses 72
5.5 Standard single moulding productions 73
5.5.1 Raw material system (for auto seats) 75
5.6 Moulds for large size foam block productions 75
5.6.1 Recommended mould fabrication 76
5.6.2 Example 76
5.6.3 Final product specifications 77
Bibliography 77
6 Selection of machinery 79
6.1 The concept of processing two-component systems 79
6.2 Selection of equipment for pre-production processing 79
6.2.1 Pre-production material mixing (phase 1) 80
6.2.2 Pre-production 'Cup-Test' or 'Box-Test' (phase 2) 80
6.3 Machinery for mixing and dispensing (phase 3) 82
6.3.1 Manual mixing and pouring 82
6.3.2 Low-pressure dispensing machines 84
6.3.3 High-pressure dispensing machines 86
6.3.4 Multiple products production 87
6.3.5 Injection dispensing 89
6.3.6 Machinery for polyurethanes as potting materials 90
Bibliography 91
7 Calculations, formulating and formulations for polyurethanes 93
7.1 Calculations 93
7.1.1 Density 93
7.1.2 Indentation force deflection 93
7.1.3 Load bearing capacities for polyurethanes 94
7.2 Cell structures of polyurethanes 96
7.3 Mixing ratio 97
7.3.1 Component A: B 97
7.3.2 Isocyanate index 98
7.3.3 Pump rates versus flow rates 99
7.3.4 Material flow versus mould volume 99
7.4 Compressed air 100
7.5 Calculating water requirements 100
7.6 Calculating electrical power 101
7.7 Formatting 103
7.7.1 Basic components 104
7.8 Conventional formulations 109
7.8.1 Foam cost calculation 110
7.9 Financial calculations 110
7.9.1 Breakeven point 112
7.9.2 Contribution margins 113
7.9.3 Gross profit margin 113
7.9.4 Cashflow 113
7.9.5 Quick performance indicators 114
Bibliography 115
8 Processing, moulding methods and troubleshooting 117
8.1 Manual mix and pour 118
8.1.1 Component data 118
8.1.2 Product 118
8.1.3 Moulds 118
8.1.4 Material requirement calculation 119
8.1.5 Processing method 119
8.1.6 Cutting and fabrication 120
8.1.7 Recycling of foam waste 120
8.2 Spraying systems 120
8.2.1 Application methods 121
8.2.2 Two-component polyurethane system for insulating large areas 121
8.3 Self-skinning, rigid and flexible polyurethane casting foams 123
8.3.1 Mould preparation 123
8.3.2 Polyfoam compaction calculation 123
8.3.3 Mixing components 123
8.3.4 Curing procedure 124
8.3.5 Finishing products 124
8.3.6 Storage life 125
8.4 Intermittent process 125
8.4.1 Foam blocks for mattresses 125
8.4.2 Polyurethane foam mattresses 126
8.5 Dispensing two-component polyurethane systems 130
8.5.1 Low-pressure dispensing 131
8.5.2 High-pressure dispensing 131
8.5.3 End applications 132
8.6 Moulding with two-component systems 132
8.6.1 Foam re-activities 133
8.6.2 Calculation of throughput 134
8.6.3 Free-rise density 134
8.6.4 Foam structure 134
8.6.5 Filling the moulds 134
8.6.6 Recommended pouring patterns 135
8.6.7 Using mould release agents 135
8.6.8 In-mould coatings 136
8.6.9 Moulding with inserts 136
8.6.10 Mould clamping 136
8.6.11 Mould cleaning 137
8.6.12 Flushing the mix head 137
8.6.13 Lead-tag when processing 137
8.7 Troubleshooting 138
8.7.1 Deficiencies in large foam block manufactures 138
8.7.2 Defects in moulding 139
Bibliography 139
9 Project set-up for small volume foam producers 141
9.1 The complete system 141
9.2 Raw material systems 142
9.3 The foaming process in brief 143
9.3.1 Foam cutting system 143
9.4 Manufacture of flexible foam blocks for mattresses 144
9.4.1 Making a flexible foam block for 'Queen-Size' mattresses 144
9.4.2 Production specifications 145
9.4.3 Calculating size of foam block required 145
9.4.4 Processing method 146
9.4.5 Fabrication and cutting process 146
9.5 Manufacture of high-resilience foam blocks for office and domestic cushions 147
9.5.1 Speciality HR grade 148
9.5.2 Production data 148
9.5.3 Mould requirements 148
9.5.4 Calculating material required for pour per block 149
9.5.5 Processing method 149
9.5.6 Cutting of foam blocks 150
9.6 Manufacture of viscoelastic/memory foam blocks for mattresses 150
9.6.1 Mattress size 150
9.6.2 Mould construction 151
9.6.3 Calculating material per pour 151
9.6.4 Processing method 151
9.6.5 Important quality checks 152
Bibliography 152
10 A case study: reduction of excessive waste, improvement of foam quality and process efficiency 153
Introduction 153
10.1 Analysis of Concerns 153
10.2 Overall concerns 154
10.3 Pre-planning of assignment 154
10.4 Training parameters and methodology 155
10.5 Overall production process as observed 155
10.5.1 Recommended new procedure 157
10.6 Post-production storage 159
10.6.1 Recommendations 159
10.7 Cutting and fabrication 159
10.8 Quality control system set up 160
10.9 Assembly and finishing 161
10.9.1 Recommended solutions 161
10.10 Process efficiency 161
10.11 Recycling section 162
10.12 Marketing 162
10.12.1 Solutions implemented 162
10.13 Conclusion 162
Appendix 1 Some suppliers of two-component polyurethane systems, dispensing and cutting machines 163
Appendix 2 Recommended solutions for deficiencies in PU parts moulding and block moulding 165
Appendix 3 Glossary of PU terms 167
Abbreviations 171
Index 173
