Polyurethane Foams 4C%SMITHERS. Practical Guide to Flexible %))/ R A P R A

Transcription

1 Practical Guide to Flexible Polyurethane Foams Chris Defonseka 4C%SMITHERS %))/ R A P R A A Smithers Group Company Shawbury, Shrewsbury, Shropshire, SY4 4NR, United Kingdom Telephone: +44 (0) Fax: +44 (0)

2 1 Introduction Brief History Flexible Foams Rigid Polyurethane Foams Automotives Elastomers Insulation Moulded Parts Spray Roofing Systems Speciality Urethane Systems Types of Foams Basic Foam Grades Viscoelastic Foam Mattresses: Marketing Hype or Molecular Miracle? Flexible Slabstock Foams What is a Flexible Polyurethane Foam? What is a Viscoelastic Foam? Characteristics of Viscoelastic Foams Physical Properties of Viscoelastic Foams Performance Testing of Viscoelastic Foams Reduction and Relief of Pressure Hyper or Pseudo Effects? Viscoelastic Foam: Summary End Applications 13

3 Practical Guide to Flexible Polyurethane Foams 2 Basic Chemistry 2.1 Brief Introduction 2.2 Organic Chemistry Basics History Characteristics Properties Melting and Boiling Properties Solubility Nomenclature Structural Presentation 2.3 Classification of Organic Compounds Functional Groups Aliphatic Compounds Aromatic Compounds Heterocyclic Compounds Polymers Organic Synthesis Organic Reactions Inorganic Chemistry Industrial Inorganic Chemistry 2.5 Classification of Inorganic Chemistry Coordination Compounds Main Group Compounds Transition Metal Compounds Organometallic Compounds Cluster Compounds Bio-inorganic Compounds Solid State Compounds Qualitative Theories 26 viii

4 Contents Molecular Symmetry Group Theory Basics of Analytical Chemistry Qualitative Analyses Flame Test Gravimetric Analyses Volumetric Analyses Mass Spectrometry Electrochemical Analyses Microscopy 29 3 Basic Polymer Chemistry What is a Polymer? Polymer Synthesis Modification of Natural Polymers Polymer Properties Monomers Microstructure Chain Length Molecular Mass (Weight) Polymerisation Condensation Polymerisation Mechanical Properties Tensile Strength Young's Modulus of Elasticity Melting Point Glass Transition Temperature Mixing Behaviour Polymer Degradation 40 4 Polyurethane Raw Materials Polyols 41 IX

5 Practical Guide to Flexible Polyurethane Foams Graft Polyols Isocyanates Bio-polyols 4.2 Catalysts 4.3 Blowing Agents Surfactants Methylene Chloride Additives Pigments Fillers Retardants Anti-oxidants Anti-static Agents Cell Openers Plasticisers Anti-bacterial Agents Ultraviolet Stabilisers Colorants Colour Basics Foam Hardeners Crosslinkers Compatibilisers Accessories Kraft Paper Machine-glazed Paper Polyethylene-coated Paper Peelable Kraft Paper Plastic Films Mould Release Agents Summary 52 x

6 Contents 5 Properties and Foaming Technology of Polyurethane Foam Properties of Polyurethane Foam Basic Physical Properties Tension Test (Tensile Strength) Tear Resistance Airflow Resilience Fogging Durability In Industrial Applications Foam is a Good Air Sealant Closed Cell Foams Foams have Structural Advantages Foam usage in Sound Control Foaming Technology Raw Materials and Their Functions Polyols Di-isocyanate Water Auxiliary Blowing Agents ; Catalysts Silicone Surfactants Graft Polyols Extenders Colourants Fillers Additives Foaming Process Mixing Nucleation 64 xi

7 Practical Guide to Flexible Polyurethane Foams Expansion Cell Opening Gelation Curing Storage of Foam Blocks Cutting and Fabrication Filled Foam Type of Filler How Much Filler can be used? Effects of Changes in Physical Properties Processing Difficulties Description of Additional Equipment Procedure 69 6 Foaming Calculations, Other Calculations and Formulations Calculations Density Mixing Ratio Isocyanate Index Ratio Calculation Pump Rates Per Minute versus Flow Rate Machine Flow Rate versus Mould Volume Calculations for Making Large Foam Blocks: Discontinuous Process Calculation of Material Required Calculating Raw Material Components Typical Formulations Conventional Foam (Density Range kg/m3) High-resilience Foams Viscoelastic Foam 80 xii

8 Contents Slab Stock Foam (Continuous Foaming) Calculating Indentation Force Deflection Calculating Electrical Power Basic Example as a Guideline Calculating Water Requirements Compressed Air Air Pressure versus Volume Calculator Financial Indicators Breakeven Point Return on Equity Return on Assets Gross Profit Margin Cash Flow Contribution Margin Debt to Equity Ratio Quick Performance Indicators Return per Kilogramme Cost per Kilogramme Breakeven Analysis Recommended Basic Foam Formulations To Save Waste on Foam Buns (Blocks) 92 7 Plant Machinery and Equipment Mould Design Design Philosophy Defining Product Requirements Loading Conditions Environmental Conditions Dimensional Requirements Preliminary Computer-aided Design Model 98 xiii

9 Practical Guide to Flexible Polyuretbane Foams Material Selection Process Selection Process Influences Orientation of the Final Product Computer Simulation Shrinkage and Warping Basic Moulds for Flexible Foams Foaming Machinery and Equipment Low-pressure Machines High-pressure Machines Images of Foaming Machines Foam Cutting and Fabrication Horizontal Cutting Vertical Cutting Specialised Cutting Manufacturing Processes for Flexible Foams Ill 8.1 Box Process for Small-volume Producers Ill Process Advantages Disadvantages Discontinuous Process Manual Process Advantages Disadvantages Semi-automatic and Automatic Processes Advantages Disadvantages Viscoelastic Discontinuous Block Foaming Continuous Process 117 xiv

10 Contents Advantages Disadvantages Maxfoam System Basic Principles Basic Features of the Maxfoam System Vertifoam Vertical Foaming System Varimax Continuous System C-Max High-pressure System CarDio Process Viscoelastic Continuous Foaming Laboratory-scale Production Inherent Waste Factors Moulded Flexible Polyurethane Foams Component A Effects of Temperature on Diphenylmethane Di-isocyanate Polyol Blends Basic Chemical Reactions Shipping Containers for Component Systems Checking for Water Contamination Unloading and Storage of Chemicals Preparing for Production Filling the Day Tanks Calibration of Processing Equipment Foam Re-activities Throughput Free Rise Density Foam Structure Filling the Moulds Pouring Pattern Tips About Moulds 132 xv

11 Practical Guide to Flexible Polyurethane Foams Mould-release Agents In-mould Coatings Moulding with Inserts Mould Clamping Mould Cleaning Flushing the Mixhead Lead-lag Recharging Day Tanks Examples of Typical Processing Material Storage Handling of Raw Material Moulds Mixing and Weighing Procedures Tips for Minimising Waste Basic Safety Factors Buildings Storage of Raw Materials Production Safety Provisions Basics of Spill Management Recommended Safety Equipment Handling Precautions Health and Industrial Hygiene Polyols Isocyanates and Prepolymers Component Systems Other Raw Materials Spill Management 147 xvi

12 Contents 10 Setting-up a Manufacturing Plant for an Entrepreneur Example A: Manual Operation Raw Materials Moulds Cutting and Fabrication Hot-wire Cutting Machine Production Method Example B: Making Large Foam Blocks Foaming Systems Description of a Typical Semi-automatic Batch Foaming Plant Foaming Machine Foam Cutting Machines One Circular (Carousel) Cutting Machine Vertical Cutting Machine Foam-shredding Machine Fully Automatic Operation Production (Manual or Semi-automatic) Manufacturing Plants for Large-Volume Producers Planned Production Location and Factory Buildings Storage of Raw Materials Storage Conditions Tank Room Trough Paper General Machinery Basic Equipment Utilities Plant Layout In-house Laboratory 169 xvii

13 Practical Guide to Flexible Polyurethane Foams Quality Control Safety Systems FoamProduction Foam Cutting and Fabrication Recycling of Foam Waste Recommendations for Process Efficiency Basic Laboratory Equipment Recommendations for the Efficiency of Foam Plants Key Factors on a Production Floor Preventive Maintenance in Foam Plants Guidelines for a Quality Control System What is a Control Chart? What is an X-R Chart? What is a P Chart? General Recommendations for Troubleshooting 184 Glossary of Terms 189 Appendix Appendix Abbreviations 219 Index 221 xviii