Polyesters, unsaturated application areas

Polyester resins. The fire-performance characteristics of unsaturated polyester resins are of utmost importance in many application areas, particularly in the construction, transportation and electronics industries ( 1 3). Consequently, these plastics represent one of the major growth areas for fire retardants in recent years ( 1 4). 

As can be deduced from plant purchases, the PRC is still at the formative stage where emphasis is on producing only the most basic petrochemicals. No plants were purchased for producing dibasic acids (phthalic and maleic anhydrides, etc.) and fluro-carbon or tetrafluoro ethylene or some of the advanced engineering plastics like ABS polyacetals, polycarbonates, polyimides or any other unsaturated polyesters. Another important area of low Chinese activity is thermoplastics for space and defense applications. ... 

As discussed previously, there are thousands of unsaturated polyester resins based on the available chemical constituents. However, major application areas require specific performance and the unsaturated polyester resins used can be broadly categorized by the major chemical constituents that deliver the specific performance necessary. Table 21.5 contains such a categorization. This should be used as a general reference because discrete, end-product performance may dictate a departure from these general categorizations. 

The crosslinking copolymerization of unsaturated polyesters with styrene is utilized industrially for the production of surface coatings. More extensive are applications in fiber-reinforced plastics where the unsaturated polyesters are used as a matrix for inorganic and organic fibers (see Example 5-20). Areas of application are (large) parts in boats, vehicles, and sport equipment construction. 

The reactive processing at polyurethane - unsaturated polyester mixtures, which is of special interest this problem has also been investigated.288 Making compounds of these polymers after polymerization is impossible because neither can be melted or disolved. However, the reactive processing technique makes it possible to prepare materials based on these polymers by injecting of the components of the reactive mix into a mixing chamber. This approach allows us to obtain materials with new performance characteristics and enlarged areas of applications. 

Several different processes can be used to produce a laminate. In what is called the hand application process, for example, glass-fiber mats are impregnated with unsaturated polyester resins. The impregnated mats are then removed from the mold by hand and pressed between rollers. The final molding is effected by cold pressing. The method is suitable for small numbers of objects with large surface areas (e.g., boat hulls). 

Unsaturated Polyester. Commercially available unsaturated polyester (39) has found a large number of applications in many areas, eg, auto industries and coating materials. A water-soluble imsaturated polymer with the molecular weights of 11,000-13,000 g/mol was cross-linked with the RAMEB-complexed styrene at 25°C using 4 mol% of the water-soluble redox initiator. A comparative experiment with uncomplexed comonomer stsu ene showed that higher yield and a higher content of polyst5Tene in the copolymer was achieved in the presence of RAMEB (40). 

In coatings, one of the main applications of unsaturated polyester resins is in furniture and wood finishes. They are also used in gel coats for boats and bathroom fixtures. Another important area of application is in automotive fillers and putties. Unsaturated polyesters are also widely used in chemical resistant coatings and linings for chemical and petrochemical storage tanks. 

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