ABSTRACT
Evolution and Perspectives 240
Evolution of Inorganic Ultraviolet Filters 240
Titanium Dioxide and Zinc Oxide 241
Perspectives for Inorganic UV Filters 241
Physical and Chemical Properties of Titanium Dioxide and Zinc Oxide 242
General Properties 242
Titanium Dioxide 242
Zinc Oxide 243
Isoelectric Point 244
Photocatalytic Activity 244
Glycol Method 246
Vitamin Method 246
Optical Behaviors 246
Scattering 247
Absorption 247
Manufacturers of Inorganic Ultraviolet Filters 248
Production of Micronized Titanium Dioxide 249
Manufacturers of Micronized Titanium Dioxide 250
Typical Specifications of Micronized Titanium Dioxide 250
Production and Manufacturers of Micronized Zinc Oxide 250
Typical Specifications of Micronized Zinc Oxide 252
Surface Treatment 252
Background 252
Surface Properties of Micronized Pigments 253
Inorganic/Organic Surface Treatments 254 Popular Surface Treatments for Micronized Pigments 255
Surface Treatments of Micronized Titanium Dioxide or Zinc Oxide
for Use with Avobenzone 255
Hydrophilic Surface Treatments for Micronized Pigments 255
Selecting the Proper Surface Treatment 255
Influence of Particle Size on UV Attenuation by TiO2 and ZnO 256
Particle Size 256
Influence of Particle Size on UV Attenuation 257
Titanium Dioxide 257
Zinc Oxide 259
Characterization of TiO2 and ZnO Dispersions 261
Dispersion of Inorganic Ultraviolet Filters 264
Objectives of the Dispersion Process 264
Index of Agglomeration 265
Advantages of Dispersions 266
Incorporating Micronized Pigments and Dispersions into Formulations 266
Producers of Dispersions 266
Formulations 267
Guidelines 267
Emulsifiers and Additives 269
Determining Suitable Levels of Actives 269
Foundations and Daily UV Lotions 270
Formulating with Zinc Oxide 270
Obtaining Broad-Spectrum Protection 271
Sample Formulations 272
W/O Waterproof Sunscreen Formula SPF 30þ 272 O/W Sunscreen Lotion SPF 27 272 Sunscreen Cream Gel 273
Sprayable O/W Sunscreen SPF 15þ 274 Regulations, Claims, Toxicity, and Testing 275
Summary 276
References 276
EVOLUTION AND PERSPECTIVES
Evolution of Inorganic Ultraviolet Filters
The popularity of inorganic ultraviolet (UV) filters with consumers and formula-
tors results from their effectiveness and safety. It is disclosed in JP Application
No. 1981-161,881 that when 0.1-40% of ultrafinely divided titanium oxide with
a particle size of 10-30 nm, which has been rendered hydrophobic, is blended
into cosmetic base materials, it transmits visible light but reflects and scatters
the harmful UV rays (1).
