GELS HANDBOOKVolume 3

Applications

Editors-in-Chief

Yoshihito Osada and Kanji Kajiwara

Associate Editors

Takao Fushimi, Okihiko Hirasa,Yoshitsugu Hirokawa, Tsutomu Matsunaga,

Tadao Shimomura, and Lin Wang

Translated by

Hatsuo Ishida

ACADEMIC PRESSA Harcourt Science and Technology Company

San Diego San Francisco New York BostonLondon Sydney Tokyo

Contents

Preface xxiContributors xxiii

VOLUME 3 APPLICATIONS

Chapter 1 Sanitary Products 1

Section 1 Disposable Diapers1 Introduction 42 Evaluation of Disposable Diapers 53 Market for Disposable Diapers for Children 54 Development of Trend of Children's Disposable Diapers 75 Market Share and Development of Adult Disposable Diapers6 Superabsorbent Polymers for Disposable Diapers 11

6.1 Crosslink Density and Absorbency 116.2 Surface Crosslinking and Absorbency 136.3 Particle Sizes and Absorbency 156.4 Permeability 15

7 Environmental Problems 178 Future Directions 18References 19

Section 2 Sanitary Napkins

1 Introduction 212 History of Sanitary Napkin 21

vi Contents

3 Market Share Sanitary Napkins 233.1 Worldwide Market 233.2 Asian Market 243.3 Japanese Market 25

4 Structure of Sanitary napkins 265 Development of Superabsorbent Polymers for Sanitary Napkins 28

5.1 Absorbency for Blood 285.2 Improvement of Superabsorbent Polymers 29

6 Future Directions 33References 34

Chapter 2 Daily Commodities 35

Section 1 Cosmetics

1 Skin Care Cosmetics 381.1 Introduction 381.2 Viscosity-Increase Functions 401.3 Emulsification 461.4 Moisture Holding 481.5 Conclusion 49

2 Hair Care Cosmetics 502.1 Classification of Hair Care Gels 502.2 Styling Gels 502.3 Conditioning Gels 55

3 Cosmetics for Cleaning 563.1 Face Cleanser 573.2 Body Cleansers 583.3 Hair Cleansers 59

References 64

Section 2 Air Fresheners and Deodorizers

1 Introduction 662 Gel Air Fresheners and Deodorizers 67

2.1 Hydrophilic Types 682.2 Oleophilic Gel Air Fresheners 71

3 Vaporization of Fragrances from Hydrogels 744 Future Development of Gel Air Fresheners and Deodorizers 76References 76

Contents vii

Section 3 Disposable Portable Heaters1 Introduction 772 Future Trends for Disposable Portable heaters 78

(1) Use of Viscous Nature of Gels 79(2) Use of Super-Controlled Release Properties of Gels 79(3) Use of Thermoresponsive Nature of Gels 79

Section 4 Sanitary products for Pets1 Introduction 812 Pet Sheets and SAP 81

2.1 Use of Pet Sheets 812.2 Structure of Pet Sheets 812.3 Pet Sheets and SAP 81

3 Toilet Sand for Pets and SAP 833.1 What is Toilet Sand for Pets? 833.2 Use of Toilet Sand for Pets 833.3 Toilet Sands and SAP 84

References 85

Section 5 Photographic Films

1 Silver Halide Photosensitive Materials 862 Gelatin Gels 87

2.1 Physical Crosslinking of Gelatin Gels 872.2 Chemical Crosslinking of Gelatin Gels 87

3 Swelling of Uncrosslinked Gelatin Film 883.1 Swelling of Gelatin Film and Its Crystallinity 883.2 Swelling towards the Plane Direction of a Gelatin Film 883.3 Other Parameters that Control Swelling 90

4 Swelling of Crosslinked Gelatin Films 914.1 Rate of Swelling of Crosslinked Gelatin Films 914.2 Reticulation 934.3 Swelling of Gelatin Gels by Ionic Crosslinking 934.4 Control of Development-Agent Permeation by PolymerBlends 94

5 Mechanical Properties of Gels 955.1 Relationships between the Modulus and Crystallites of GelatinGels 965.2 Moduli of Gelatin Gels that Contain a Crosslinking Agent 98

viii Contents

6 Conclusions 101References 101

Section 6 Domestic Oil-Treatment Agents

1 Introduction 1032 Inhibition Mechanisms of Gelation 1043 Improvement of Gel Strength 105

3.1 Adsorption of Lecithin by Silica Gel 1053.2 Fiber Structure Changes by Addition of a Sodium Salt 106

References 107

Chapter 3 Foods and Packaging 109

Section 1 Water-Absorption Sheet for Maintaining Freshness of Foods

1 Techniques to Maintain Freshness and Functional PackagingMaterials 111

2 Basic Structure and Functions of Water-Absorption Sheet forFreshness Preservation of Foods 115

3 Improvement of Water-Absorption Sheet for Freshness Preservation ofFoods 116

4 Development Trend of Water-Absorption Sheets for SpecificApplications 117References 119

Section 2 Multifunctional Packaging Materials for FreshnessPreservation

1 Water-absorbing, Multifunctional Packaging Materials 1212 Multifunctional Packaging Materials with Water-Absorption and

Antibacterial Functions 1223 Multifunctional Packaging Materials with Water Absorption and

Deodorant Functions 1254 Other Multifunctional Packaging Materials 125References 125

Section 3 Coolants for Food Transportation

1 Basic Structure and Function of Coolants for FoodTransportation 127

Contents ix

2 Improvement of Coolant Shapes for Food Transportation 1273 Immersing Self-absorbing Coolants 1284 Improvement of Polymer Hydrogel for Coolants 1305 Application Examples of Coolants Tailored for a Particular Food 131References 132

Section 4 Contact-Dehydration Sheet for Food Processing

1 Structure and Function of Contact-Dehydration Sheet for FoodProcessing 134

2 Benefits for Cooking and Application Examples of Contact-Dehydrating Sheet 135

3 Improvement towards Low-Cost Contact-Dehydration Sheets 1374 Package Systems that Utilized Contact-Dehydration Sheet 137References 139

Chapter 4 Medicine and Medical Care 141

Section 1 Gels for Cell Culture

1 Introduction 1452 Type I Collagen Gel 1473 Agarose Gels 1494 Matrigels 1505 Conclusion 152References 153

Section 2 Applications of Gel for Plastic Surgery:Artificial Breasts and Skin

1 Hydrogels and Lyogels 1542 Silicone Gel-Filled Breast Prosthesis 1553 Hydrogel-Filled Breast Prosthesis 1594 Skin Substitutes 159

4.1 Wound Dressings 1604.2 Tissue Reorganization Template 162

5 Silicone Gel Sheeting 162References 163

x Contents

Section 3 Soft Contact Lenses

1 Introduction 1662 History of Contact Lenses 1673 Classification and Components of Contact Lenses 1674 Manufacturing Method of Soft Contact Lenses 1705 Properties of Soft Contact Lenses 1726 Future Development 174

6.1 Disposable Lenses 1756.2 Hybridization 177

References 178

Section 4 Absorbable Hydrogels for Medical Use

1 Introduction 1802 Hemostatic Agents, Adhesives, and Sealants 1803 Adhesion Prevention 1834 Tissue Engineering Matrices and Separation Membranes 1865 Conclusion 186References 187

Section 5 Bioadhesion Gels and Their Applications

1 What is Bioadhesion Gel? 1882 Application Areas of Bioadhesion Gels 1893 Adhesion Mechanisms of Bioadhesion Gels 1894 Application Examples Based on Location 191

4.1 Eyes 1914.2 Nasal Cavity 1914.3 Oral Cavity 1954.4 Uterus and Vagina 1964.5 Alimentary System 1964.6 Intestine 199

5 Conclusion 199References 199

Section 6 Transdermal Patches1 Introduction 2012 Manufacturing of Patches 2013 Characteristics of Patches 2034 Current Trend of Transdermal Patches 203

Contents xi

5 New Approaches for Transdermal Patches 209References 210

Section 7 Ointments for Antiinflammatory Drugs

1 Introduction 2112 Development of Drug Delivery Systems 213

2.1 Solubility 2132.2 Stability 2132.3 Absorptivity 2162.4 Viscosity Enhancer 216

3 Future Trends 219References 220

Section 8 Application of Chitosan Medical Care

1 Introduction 2212 General Properties of Chitin and Chitosan 2233 Preparation and Application of Chitin Gels 2234 Preparation and Application of Chitosan Gels 2255 Conclusion 227References 228

Section 9 Sustained Drug Delivery by Gels

1 Introduction 2302 Polymers and Gels Used for Drug Delivery Systems 2313 Gel Functions and Controlled Drug Delivery 231

3.1 Blocking Effect in Gel Diffusion 2323.2 Application of Swelling-Shrinking Phase Transition ofGels 2333.3 Application of Blend Gels to DDS 235

4 Gels in DDS 239References 240

Section 10 Medical Sensors

1 Introduction 2412 Summary of Medical Sensors 2413 Application of Gels to Medical Sensors 2434 Functions of Polymer Gels and Their Application to Sensor

Technology 244

xii Contents

5 Conclusion 246References 246

Section 11 Encapsulation of Cells in Hydrogels

1 Introduction 2482 Encapsulation Method for Live Cells in Hydrogels 248

2.1 Ion Complex 2492.2 Formation of Hydrogen Bonding 2502.3 Use of the Phase Change of Polymer Solutions 2502.4 Use of Low Cell Toxicity Solvents 2502.5 Use of Photodimerization 2542.6 Formation of Hydrogels by the Oxidation of Thiol 254

3 Application of Cells Encapsulated in Hydrogels 2553.1 Bioartificial Organs 2553.2 Prevention of Cell Aggregation 2573.3 Protection of High Molecular Weight DNA 257

References 257

Chapter 5 Farming and Agriculture 259

Section 1 Characteristics of Superabsorbent Polymer (SAP)-Mixed Soil

1 Introduction 2612 Characteristics of SAP for Agriculture and Greening 2623 Availability of Water Held in SAP to Plants 2654 Characteristics of a SAP Mixed Soil 268

4.1 Changes 2684.2 Change in the Distribution of Three Phases 2684.3 Evaporation Characteristics from SAP-mixed Soil 2714.4 Other Properties 272

References 274

Section 2 Application of Superabsorbent Polymers in JapaneseAgriculture and Greening

1 Introduction 2762 Methods to Mix SAP into Soil 277

2.1 Mixing into Vegetable Culture Beds 2772.2 Water-saving Culture 277

Contents xiii

2.3 Transplantation of Trees 2792.4 Mixing SAP into Media of Bench Culture 2812.5 Fluid Seeding 2812.6 Seed Coating and Seed Immersion 2832.7 Spray Seeding 284

3 Conclusion 284References 285

Section 3 Application of Superabsorbent Polymers to Dry Land

1 Introduction 2862 Mexico 2863 Egypt 2874 China 289References 292

Chapter 6 Civil Engineering and Construction 293

Section 1 Civil Engineering and Construction

1 Introduction 2952 Application of Water-Swelling Rubbers as Sealants 2963 Types of Sealants 296

3.1 Nonswelling Rubber-Type Sealants 2963.2 Water-Swelling Sealants 297

4 Swelling of Water-Swelling Rubbers 2985 Water-Stopping Capability of Water-Swelling Rubbers 299

5.1 Water-Stopping Properties of Water-Swelling Rubbers 2995.2 Water-Stopping Experiment for Water-Swelling Rubbers 300

6 Basic Design of Sealants 3016.1 Addition of Sealant Groove 3016.2 Use of Composites 302

7 Conclusion 302

Section 2 Prevention of Water Condensation

1 Introduction 3042 Mechanism of Water Condensation and Methods for Preventing Water

Condensation Using Polymer Gels 3053 Characteristics Required for Preventing Water Condensation 307

xiv Contents

3.1 Moisture Absorptivity 3073.2 Moisture Adjustment Ability 3083.3 Water Absorptivity 3093.4 Durability (Antifungal and Repeated Moisture Cycle Test) 311

4 Application Example of Superabsorbent Polymer Sheets as aPrevention Material for Water Condensation: Application to SnowDam 313

5 Conclusion 313References 314

Section 3 Fireproof Materials

1 Introduction 3162 Fireproof Covering Materials 3183 Application of Superabsorbent Polymers 3194 Fireproof Covering Material, Aquacover 320

4.1 Heat Absorption Effect of Heat Absorbing Packaging 3204.2 Mechanism of Heat Absorption 320

5 Future Challenges 322

Section 4 Sealed Construction Method

1 Introduction 3232 Types of Tunnel Digging Methods 3233 Various Methods in Sealed Construction Method 3244 The Characteristics of Soils from Sealed Digging 3285 Improvement of Sealed Soil 3346 Conclusion 335References 335

Section 5 Gelation of Waste Mud (Gelation of ConstructionWaste Mud)

1 Introduction 3362 Treatment and Dumping of Construction Waste Mud 339

2.1 Origin and Properties 3392.2 Treatment and Disposal of Construction Waste Mud 341

3 MImprovement Treatment of Waste Mud by Addition of a ChemicalAgent 3423.1 Inorganic Chemicals Methods 3423.2 Methods by Organic Agents 347

Contents xv

4 Conclusion 348References 348

Chapter 7 Chemical Industries 349

Section 1 Application of Gels for Separation Matrices

1 Introduction 3522 Classification of Gels Based on the Shape and Chemical

Structure of Particular Gels 3532.1 Shape of Gels 3532.2 Classification Based on Chemical Structure 353

3 Separation Mechanisms and Separation Agents 3583.1 Molecular Sieves 3583.2 Adsorption 3583.3 Ion Exchange Materials 3593.4 Special Chromatographic Separation 3603.5 Others 361

References 361

Section 2 Application for Tissue Culture of Plants

Section 3 Oleogels and Their Applications

1 Introduction 3682 Develoment of Oleogels 369

2.1 Comparison to Hydrogels 3692.2 Difference from Oil Gelation Agents 3692.3 Design of Oleogels 370

3 Form of Oleogels 3723.1 Water Dispersion Type 3723.2 Powder Type 372

4 Fundamental Properties of Oleogels 3734.1 Oil Absorption Ratio 3734.2 Oil Absorption Ratio for Mixed Oils 3744.3 Rate of Oil Absorption 3744.4 Oil Retention Capability 3754.5 Selective Absorption of Oil from Oil/Water Mixture 3754.6 Inhibition Effect of Spreading 377

xvi Contents

5 Application of Oleogels 3775.1 Oil Treatment Agents 3775.2 Sealant 3775.3 Sustained Release Matrix 3775.4 Additives for Resins and Rubbers 3785.5 Other Applications 379

6 Conclusion 379References 379

Section 4 Application of Superabsorbent Polymers Gels toOil-Water Separation (Use of Superabsorbent PolymerContaining Sheet)

1 Introduction 3812 Separation and Gelation of Fine Oil Particles and Emulsified

Oils 3832.1 Coalescence Separation of Fine Oil Particles 3832.2 Function of Hydrogels 383

3 Practical Aspects of Oil-Water Separation Sheet 3833.1 Construction of Oil-Water Separation Sheet 3833.2 Evaluation of Oil-Water Separation Sheets 3853.3 Experimental Examples of Oil-Water Separation Effects 385

4 Conclusion 389References 392

Section 5 Application of Gels to Latent Heat ThermalStorage Media

1 Introduction 3932 Inorganic Hydration Salt Type Thermal Storage Media 395

2.1 Phase Separation Phenomena 3952.2 Application of a Superabsorbent Polymer to Sodium SulfateDecahydrate 3962.3 Application Examples 398

3 Thermal Storage Media from Organic Compounds 399References 400

Section 6 Application for Electrophoresis1 Introduction 4012 Polyacrylamide and Agarose Gels 402

Contents xvii

3 Newly Developed Gels 4044 Conclusion 407References 407

Chapter 8 Electric and Electronic Industries 409

Section 1 Communication Cables

1 Introduction 4112 Properties Required of Superabsorbent Polymers for

Communication Cables 4123 Water-Absorbing Wraparound Tapes 4134 Water-Absorbing Materials made of Fibers, Strings, and

Narrow-width Tapes 4155 Jelly-like Water-Absorbing Materials 4156 Direct-Coating Type Water-absorbing Materials 4177 Application to Power Cables and Others, Conclusion 419References 419

Section 2 Batteries

1 Primary Batteries 4211.1 Introduction 4211.2 Dry Batteries and Gels 4221.3 Polymer Electrolytes and Lithium Batteries 4231.4 Nonaqueous Electrolyte Gels 4261.5 Polymer Film Primary Batteries 429

2 Auxiliary Batteries 4322.1 Introduction 4322.2 Acrylate Gels 4332.3 Performance of Auxiliary Batteries 4372.4 Characteristics of Polymer Auxiliary Batteries 4392.5 Towards Increased Energy Density of Polymer Batteries and

Future Trends 441References 443

Section 3 Fuel Cells

1 What is a Fuel Cell? 4452 Polymer Electrolyte Fuel Cells 447

xviii Contents

3 Development of Polymer Electrolyte Fuel Cells 4484 Solid Electrolytes 4495 Problems of Polymer Electrolyte Fuel Cells 4516 Conclusion 452References 453

Section 4 Sensors

1 Enzyme Sensors 4551.1 Fixation of Enzymes onto Gels and Construction

of Sensors 4551.2 Oxygen and Hydrogen Peroxide-detecting

Glucose Sensors 4561.3 Low Molecular Weight Molecule Mediator-type

Glucose Sensors 4591.4 Polymer Mediator-type Glucose Sensors 460

2 Humidity Sensors 4622.1 Introduction 4622.2 Sensors That Utilized Copolymers 4652.3 Sensors with Crosslinked Hydrophilic Polymers 4662.4 Sensors Utilizing Interpenetrating Polymer Networks 4682.5 Sensors Utilizing Graft Polymers 4692.6 Quartz Oscillator Method 474

References 475

Chapter 9 Sport and Leisure Activity Industries 479

Section 1 Sporting Goods Applications

1 Introduction 4802 Application to Sport Shoes 4823 Development of Tennis Shoes 4844 Application of Gels to Areas Other than Shoes 4885 Patented Application Examples 4896 Conclusion 489References 490

Section 2 Artificial Snow

1 Introduction 491

Contents xix

Brief Explanation of the Superabsorbent Polymer Method 4922.1 Snow Manufacturing Method 4922.2 Air Conditioning System for Cooling 492Properties of Polymer Mixed Snow 4963.1 Thermal Property Modification of Snow by Polymer 4963.2 The Friction Coefficient of Polymer Mixed Snow 4963.3 Grooming Machine 500Conclusion 501