Polyurethanes

Abstract

The article contains sections titled: 1. Introduction 2. Basic Reactions 3. Starting Materials 3.1. Polyisocyanates 3.1.1. Aromatic Polyisocyanates 3.1.2. Aliphatic Polyisocyanates 3.1.3. Blocked Isocyanates 3.2. Polyols 3.2.1. Polyether Polyols 3.2.2. Polyester Polyols 3.2.3. Polycarbonate Polyols 3.2.4. Other Polyols 3.3. Diamines and Amino‐Terminated Polyethers 3.4. Special Building Blocks 3.5. Catalysts and Additives 4. Structure and Morphology 4.1. Polyurethanes Without Segmented Structure 4.2. Polyurethanes with Segmented Structure 4.2.1. Hard and Soft Segments 4.2.2. Segregation and Morphology 4.3. Cross‐linking of Polyurethane 4.4. Polyisocyanurates 5. Production of Polyurethanes 5.1. Stoichiometry 5.2. Reaction without Solvents 5.2.1. One‐Shot Process 5.2.2. Prepolymer Processes 5.3. Reaction in Solvents 5.3.1. One‐Component Systems 5.3.2. Two‐Component Systems 5.4. Reactive One‐Pack Systems 5.5. Other Processes 6. Processing of Polyurethanes 6.1. Supply, Storage, and Preparation of Raw Materials 6.2. Metering and Mixing Technology 6.3. Processing Plants 7. Foams 7.1. Flexible Foams 7.1.1. Flexible Slabstock Foam 7.1.1.1. Raw Materials 7.1.1.2. Production 7.1.1.3. Properties 7.1.1.4. Trimming and Processing 7.1.1.5. Applications 7.1.2. Molded Flexible Foam 7.1.2.1. Production 7.1.2.2. Molding Process 7.1.2.3. Properties 7.1.2.4. Applications 7.2. Semirigid Foams 7.2.1. Applications 7.2.2. Production 7.2.3. Properties 7.3. Rigid Foams 7.3.1. Raw Materials 7.3.2. Processing 7.3.3. Properties 7.3.4. Special Types 7.4. Integral Skin Foams and RIM Materials 7.4.1. Applications 7.4.2. Production 7.4.3. Properties 8. Noncellular Polyurethanes 8.1. Cast Elastomers 8.1.1. Applications 8.1.2. Production 8.1.3. Properties 8.2. Thermoplastic Polyurethane Elastomers (TPU) 9. Polyurethane Coatings 10. Polyurethane Adhesives 11. Polyurethane Fibers 12. Polyurethanes and Isocyanates as Binders 13. Special Products 14. Safety and Ecology 14.1. Safety Precautions when Handling the Raw Materials 14.2. Emissions, Accidental Release, and Waste Disposal 14.3. Recycling/Recovery of Polyurethanes 14.4. Fire Performance of Polyurethanes 15. Economic Aspects

Preparation and characterization of waterborne polyurethane based on diphenylmethane diisocyanate‐50

“…2a, the tensile strength gradually increases from 16.5 to 34.5 MPa with increasing R from 1.3 to 2.3. [15][16][17][18] Therefore, the tensile strength and Shore A hardness of MWPU increase as R increases. As shown in Fig.…”

“…[1][2][3][4][5][6] Call for environmental protection and human health forces industries to decrease the amounts of VOCs released into the atmosphere and develop eco-friendly products. 16,18 Furthermore, the properties of IWPU such as tensile strength and water resistance are not as good as that of the WPU based on MDI. [7][8][9][10] Conventionally, isophorone diisocyanate (IPDI) was used to synthesize WPU for so many industrial applications such as matting resins and sizing agents for papermaking.…”

“…As an important alternative, WPUD will partially replace SPUD in many industrial applications, such as coatings, adhesives, inks, and paints. [18][19][20] Xu et al synthesized and characterized IWPU whose tensile strength and water absorption ratio were 0.77 MPa and 17.42%, respectively. [11][12][13][14] IPDI-based WPU (IWPU) is easier to be dispersed in water compared to the WPU that based on diphenylmethane diisocyanate (MDI) which has two phenyls in molecular chains.…”

“…[16][17][18] Besides MDI-50, polytetramethylene ether glycol-1000 (PTMEG-1000), polybutylene adipate glycol-1000 (PBA-1000), 2,2-dimethylolpropionic acid (DMPA), and 1,4-butanediol (BDO) were used for preparation of WPU by self-emulsification process. As a liquid feedstock at room temperature, MDI-50 (melting point is approximately 15°C) can be fed more conveniently in the industry compared to MDI-100 (nearly 100 wt% of 4,4 0 -diphenylmethane diisocyanate, melting point is approximately 39.5°C).…”

Albumin adducts and urinary metabolites resulting from occupational exposure to 1,5-naphthalene diisocyanate

“…Isocyanates are used for manufacturing polyurethane foam, elastomers, paints, adhesives, coatings, insecticides and consolidation of loose rock zones in coal mining or tunneling, and many other products [1,2]. Isocyanates are considered to be one of the main causes of occupational asthma [3][4][5].…”