Epoxy Resins

Ha Q. Pham

Ha Q. Pham

Dow Chemical, Freeport, Texas

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Maurice J. Marks

Maurice J. Marks

Dow Chemical, Freeport, Texas

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First published: 15 October 2005
Citations: 56

Abstract

Epoxy resins are reactive intermediates used to produce a versatile class of thermosetting polymers. They are characterized by the presence of a three-membered cyclic ether group commonly referred to as an epoxy group, 1,2-epoxide, or oxirane. The most widely used epoxy resins are diglycidyl ethers of bisphenol A derived from bisphenol A and epichlorohydrin. The outstanding performance characteristics of the thermosets derived from bisphenol A epoxies are largely conveyed by the bisphenol A moiety (toughness, rigidity, and elevated temperature performance), the ether linkages (chemical resistance), and the hydroxyl and epoxy groups (adhesive agents). In addition to bisphenol A, other starting materials such as aliphatic glycols and both phenol and o-cresol novolacs are used to produce specialty resins. Epoxy resins may also include epoxide-bearing compounds based on aromatic amine, triazine, and cycloaliphatic backbones.

A variety of reagents have been described for converting the liquid and solid epoxy resins to the cured state, which is necessary for the development of the ultimate end-use properties. The curing agents or hardeners are categorized as either catalytic or coreactive. Catalytic curing agents initiate resin homopolymerization, either cationic or anionic, as a consequence of using a Lewis acid or base in the curing process. Coreactive curing agents are polyfunctional compounds typically possessing active hydrogens that are employed up to stoichiometric quantities with epoxy resins. The important classes of coreactive curing agents include multifunctional amines and their amide derivatives, polyphenols, polymeric thiols, polycarboxylic acids, anhydrides, phenol–formaldehyde novolacs and resoles, and amino–formaldehyde resins.

The largest single use of epoxy resins is in the protective coatings market where high corrosion resistance and adhesion to substrates are important. Epoxies have gained wide acceptance in protective coatings and in electrical and structural applications because of their exceptional combination of properties such as toughness, adhesion, chemical and thermal resistance, and good electrical properties.

The article contains sections titled:

1.

Introduction

2.

History

3.

Industry Overview

4.

Classes of Epoxy Resins and Manufacturing Processes

5.

Liquid Epoxy Resins (DGEBA)

5.1.

Caustic Coupling Process

5.2.

Phase-Transfer Catalyst Process

6.

Solid Epoxy Resins Based on DGEBA

6.1.

SER Continuous Advancement Process

6.2.

Phenoxy Resins

6.3.

Epoxy-Based Thermoplastics

7.

Halogenated Epoxy Resins

7.1.

Brominated Bisphenol A Based Epoxy Resins

7.2.

Fluorinated Epoxy Resins

8.

Multifunctional Epoxy Resins

8.1.

Epoxy Novolac Resins

8.1.1.

Bisphenol F Epoxy Resin

8.1.2.

Cresol Epoxy Novolacs

8.1.3.

Glycidyl Ethers of Hydrocarbon Epoxy Novolacs

8.1.4.

Bisphenol A Epoxy Novolacs

8.2.

Other Polynuclear Phenol Glycidyl Ether Derived Resins

8.2.1.

Glycidyl Ether of Tetrakis(4-hydroxyphenyl)ethane

8.2.2.

Trisphenol Epoxy Novolacs

8.3.

Aromatic Glycidyl Amine Resins

8.3.1.

Triglycidyl Ether of p-Aminophenol

8.3.2.

Tetraglycidyl Methylenedianiline (MDA)

9.

Specialty Epoxy Resins

9.1.

Crystalline Epoxy Resins Development

9.2.

Weatherable Epoxy Resins

9.2.1.

Hydrogenated DGEBA

9.2.2.

Heterocyclic Glycidyl Imides and Amides

9.2.3.

Hydantoin-Based Epoxy Resins

9.3.

Elastomer-Modified Epoxies

10.

Monofunctional Glycidyl Ethers and Aliphatic Glycidyl Ethers

11.

Cycloaliphatic Epoxy Resins and Epoxidized Vegetable Oils

12.

Epoxy Esters and Derivatives

12.1.

Epoxy Esters

12.2.

Glycidyl Esters

12.3.

Epoxy Acrylates

12.4.

Epoxy Vinyl Esters

12.5.

Epoxy Phosphate Esters

13.

Characterization of Uncured Epoxies

14.

Curing of Epoxy Resins

15.

Coreactive Curing Agents

15.1.

Amine Functional Curing Agents

15.1.1.

Primary and Secondary Amines

15.1.1.1.

Aliphatic Amines

15.1.1.1.1.

Ketimines

15.1.1.1.2.

Mannich Base Adducts

15.1.1.1.3.

Polyetheramines

15.1.1.2.

Cycloaliphatic Amines

15.1.1.3.

Aromatic Amines

15.1.1.4.

Arylyl Amines

15.1.2.

Polyamides

15.1.3.

Amidoamines

15.1.4.

Dicyandiamide

15.2.

Carboxylic Functional Polyester and Anhydride Curing Agents

15.2.1.

Carboxylic Functional Polyesters

15.2.2.

Acid Anhydrides

15.3.

Phenolic-Terminated Curing Agents

15.4.

Melamine-, Urea-, and Phenol-Formaldehyde Resins

15.5.

Mercaptans (Polysulfides and Polymercaptans) Curing Agents

15.6.

Cyclic Amidines Curing Agents

15.7.

Isocyanate Curing Agents

15.8.

Cyanate Ester Curing Agents

16.

Catalytic Cure

16.1.

Lewis Bases

16.2.

Lewis Acids

16.3.

Photoinitiated Cationic Cure

17.

Formulation Development With Epoxy Resins

17.1.

Relationship Between Cured Epoxy Resin Structure and Properties

17.2.

Selection of Epoxy Resins

17.3.

Selection of Curing Agents

17.4.

Epoxy/Curing Agent Stoichiometric Ratios

17.5.

Catalysts

17.6.

Accelerators

18.

Epoxy Curing Process

18.1.

Characterization of Epoxy Curing and Cured Networks

19.

Formulation Modifiers

19.1.

Diluents

19.2.

Thixotropic Agents

19.3.

Fillers

19.4.

Epoxy Nanocomposites

19.5.

Toughening Agents and Flexiblizers

20.

Coatings Applications

20.1.

Coatings Application Technologies

20.1.1.

Low Solids Solventborne Coatings

20.1.2.

High Solids Solventborne Coatings

20.1.3.

Solvent-Free Coatings (100 % Solids)

20.1.4.

Waterborne Coatings

20.1.5.

Powder Coatings

20.1.6.

Radiation-Curable Coatings

20.2.

Epoxy Coatings Markets

20.2.1.

Marine and Industrial Maintenance Coatings

20.2.2.

Metal Container and Coil Coatings

20.2.3.

Automotive Coatings

20.3.

Inks and Resists

21.

Structural Applications

21.1.

Structural Composites

21.1.1.

Epoxy Composites

21.1.2.

Epoxy Vinyl Ester Composites

21.1.3.

Mineral-Filled Composites

21.2.

Civil Engineering, Flooring, and Construction

21.3.

Electrical Laminates

21.4.

Other Electrical and Electronic Applications

21.4.1.

Casting, Potting, and Encapsulation

21.4.2.

Transfer Molding

21.5.

Adhesives

21.6.

Tooling

22.

Health and Safety Factors

23.

Acknowledgments

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.