Cured polyesters

The diisopropoxy-bis-(triethanolamine)-titanate, TYZORTE [36673-16-2] is an excellent cross-linker for aqueous solutions of hydroxyl-containing polymers. The reaction product of TYZORTPT with a mixture of trialkano1 amines and dialkanolarnines or monoalkano1 amines can be used to cure polyester-based powder coatings (109). Other ligands of this type iaclude triisopropano1 amine [122-20-3] ... 

Application. Polyesters are cured by free radicals, most commonly produced by the use of peroxides. A wide range of peroxide initiators (qv) are available for use in curing polyesters. Most peroxide initiators are thermally decomposed into free radicals, and the common initiators used at room temperature requke the use of a promoter such as dimethylaniline or cobalt octoate. 

Figure 25.1. The nature of cured polyester laminating resins.

Structures present in cured polyester resin. Cross-linking via an addition copolymerisation reaction. The value of n 2-3 on average in general purpose resins... 

J.W. Cywinski, The Role of Organic Peroxides in Curing Polyester Resins and Their Influence on The Physical Properties of Re-... 

Yang, L. and Kooker, D., Cured polyester plastic compositions derived from recycled polyurethanes, US Patent 5 859 167 1999. 

Phenanthroline and some of its alkyl-substituted derivatives improve the heat stability of polyesters594 and magnetic recording tape.595 They also improve the color of cured polyester resins.596 They are also useful in various electroplating and electrolytic processes597-601... 

Table II. Ingredients of One-Step Preparation of Cured Polyester...

Studies of rheokinetics over the whole range of polyester curing is based (as for other materials) on a dynamic method, i.e., on measurements of the time dependence of the dynamic modulus at a fixed frequency, from which the time dependence of the degree of conversion (3(t). The observed dependence P(t) for polyester resins can be analyzed by an equation of the type used for other materials. Thus the following general equation was proposed for the kinetics of curing polyester and epoxy resins 69 72... 

Propellants include both rocket and gun propellants. Most rocket propellants are either Hazard Class 1.3 composites, which are based on a rubber binder, and ammonium perchlorate (AP) oxidizer, and a powdered aluminum (Al) fuel or Hazard Class 1.1 composites, which are based on a nitrate ester, usually nitroglycerine (NG), nitrocellulose (NC), HMX, AP, or polymer-bound NC. If a binder is used, it usually is an isocyanate-cured polyester or polyether. Some propellants contain combustion modifiers, such as lead oxide. 

Epoxies, isocyanate cured polyester, and cyanoacrylates are used to bond acetal copolymer. Generally, the surface is treated with sulfuric-chromic acid. Epoxies have shown 150- to 500-psi shear strength on sanded surfaces and 500- to 1000-psi on chemically treated surfaces. Two-component epoxies give slightly lower bond strengths. However, they bond acetal to itself and to many other materials. 

Commonly used adhesives for both PET and PBT substrates are isocyanate cured polyesters, epoxies, and urethanes. Surface treatments recommended specifically for PBT include mechanical abrasion and solvent cleaning with toluene. Gas plasma surface treatments and chemical etch have been used where maximum strength is necessary. 

Polyester resins possess premium performance properties such as exterior durability, gloss, flexibility hardness, color stability, and versatility of cure. Polyesters are used in product finishes for household appliances, food and beverage containers, aircraft and equipment, automotive primers and bake coats, metal furniture, and fixtures. For example, water-soluble saturated polyesters are used in industrial baking paints, and in combination with melamine resin. Polyesters can be formulated in high solids and waterborne formulations to meet the requirements for the low VOC coatings being mandated by the EPA. 

The properties of cured polyesters are affected by their structural elements. These elements include the structure and ratio of acids and glycols, the type of end-group present, the type of unsaturation and the distribution of various repeating units. 

The chemical structure of glycols influences the tensile and flexural properties of cured polyester resins. Glycols with more carbon atoms generally... 

Water absorption is less in the case of cured polyesters containing aromatic acids, compared with those containing aliphatic saturated acids. Factors that contribute towards the flexibility of cured polyesters also tend to promote water absorption. The water sensitivity of cured resins also depends on the relative amounts of terminal hydroxyl and terminal carboxyl groups. 

With continuous ageing, degradation of the cross-links occurs resulting in loss of flexural strength in the cured polyester. Use of proper antioxidants improves the resistance to heat deterioration. 

Owing to this rapid cure, a compressive strength of 40 N/mm is possible within 2 h at temperatures down to 4°C (Shaw, 1993a). The properties of polyester binder depend primarily upon the chemical composition of the polyester resin component. Typical physical properties of cured polyester binders for concrete overlays are given in Table 9.3 (ACI, 1993). 

Table 93 Typical physical properties of cured polyester concrete...

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