Hydrolysis polyester resin

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

Dry chlorine has a great affinity for absorbing moisture, and wet chlorine is extremely corrosive, attacking most common materials except HasteUoy C, titanium, and tantalum. These metals are protected from attack by the acids formed by chlorine hydrolysis because of surface oxide films on the metal. Tantalum is the preferred constmction material for service with wet and dry chlorine. Wet chlorine gas is handled under pressure using fiberglass-reinforced plastics. Rubber-lined steel is suitable for wet chlorine gas handling up to 100°C. At low pressures and low temperatures PVC, chlorinated PVC, and reinforced polyester resins are also used. Polytetrafluoroethylene (PTFE), poly(vinyhdene fluoride) (PVDE), and... 

Chlorendic Acid. Chlorendic acid [115-28-6] and its anhydride [115-27-5] are widely used flame retardants. Chlorendic acid is synthesized by a Diels-Alder reaction of maleic anhydride and hexachlorocyclopentadiene (see CyclopentadlENE and dicyclopentadiente) in toluene followed by hydrolysis of the anhydride using aqueous base (60). The anhydride can be isolated directly from the reaction mixture or can be prepared in a very pure form by dehydration of the acid. The principal use of chlorendic anhydride and chlorendic acid has been in the manufacture of unsaturated polyester resins. Because the esterification rate of chlorendic anhydride is similar to that of phthalic anhydride, it can be used in place of phthalic anhydride in commercial polyester... 

Propylene glycol, i.e., 1,2-propanediol (1,2-PDO), is an important commodity chemical. It is used as biodegradable functional fluids and as precursors for the syntheses of unsaturated polyester resins and pharmaceuticals (9-10). Propylene glycol is currently produced from petroleum-derived propylene via oxidation to propylene oxide and subsequent hydrolysis (9, 11). However, the rising cost of propylene provides an incentive to find a substitute to propylene for this... 

Table 10.3 summarizes the uses of propylene oxide. Propylene glycol is made by hydrolysis of propylene oxide. The student should develop the mechanism for this reaction, which is similar to the ethylene oxide to ethylene glycol conversion (Chapter 9, Section 8). Propylene glycol is a monomer in the manufacture of unsaturated polyester resins, which are used for boat and automobile bodies, bowling balls, and playground equipment. 

In conclusion, we would like to mention that, in addition to this new direction, a large consumer of metal alkoxides (initially aluminium and titanium) is by tradition the technology of materials, where the alkoxides are used for hy-drophobization and for cross-linking of the polyhydroxocompounds, epoxides and polyester resins, and organosilicon polymers. The products of the partial hydrolysis and pyrolysis of alkoxides — polyorganometalloxanes — are applied as components of the thermally stable coatings [48J. 

Manufacture of propylene glycol (CH3-CHOH-CH2OH) consumes about 30 percent of the propylene oxide produced. Like ethylene oxide, propylene oxide undergoes hydrolysis to yield the corresponding glycol. Propylene glycol is mainly used to make polyester resins, but it is also used in foods, pharmaceuticals, and cosmetics. 

Although linear polyester resins do not readily undergo heat curing, they form extremely flexible paint films with excellent adhesion to metal substrates. Poiyisocyanate resins are more resistant to hydrolysis than amino resins. Polyester-polyurethane paints therefore exhibit improved resistance to moisture and weathering but are more expensive. 

Industrial Paints. Stoving enamels used to spray or dip-coat machinery, domestic appliances, vehicles, and office furniture are termed industrial paints. On account of their good adhesion and resistance to hydrolysis, polyester-melamine stoving enamels provide very good protection of metal surfaces against undercoat corrosion creep. Polyester resin grades are available for special mechanical requirements (high impact resistance, hardness, abrasion resistance) or for exterior use (weather resistance). 

The choice of fibrous reinforcements can have as important an effect on moisture and hydrolysis resistance as the resin matrix, especially when polyester resins are used. Low-alkaU content E-glass is almost universally used for glass reinforcements and is coated with an organosilane size to protect it, as well as to improve the bond between it and the resin. If chopped strand glass mat is utilized as a reinforcement, the type of binder... 

Chem. Descrip. Sat. polyester resin Uses Binder in stoving top coats and primers Features Oil-free good resist, to hydrolysis Properties Clear to si. cloudy appearance sol. in water, alcohols, glycol ethers dens. = 1.09 g/ml (20 C) vise. 7250 01250 mPa-s-(23 C) acid no. 23 03 pH 8.2 00.4 (thinned 1 2 with demineralized water) flash pt. 55 C 55 02% NV Bayhydrol D 270 [Bayer AG]... 

Vinyl ester resins are similar to unsaturated polyester resins in that they are cured by a free radical initiated polymerisation. However, they differ from the polyesters in that the unsaturation is at the ends of the molecule rather than along the polymer chain. Unlike polyesters, vinyl esters show a greater resistance to hydrolysis as well as lower peak exotherm temperatures and less shrinkage upon cure. Cured vinyl ester resins exhibit excellent resistance to acids, bases and solvents. They also show improved strain to failure, toughness and glass transition temperatures over polyesters. They can be used in filament winding, pultrusion, resin injection, vacuum moulding and conventional hand lay-up. 

Some polymerizable esters can be used as a copolymerizable internal plasticizer in technical applications. The best known of the group is diallyl phthalate (DAP), which is used to replace styrene, divinyl benzene, or methyl methacrylate in unsaturated polyester resins. It has a very low vapour pressure (300°C boiling point), leading to significant reduction in loss through evaporation. It considerably improves properties such as hardness, chemical resistance, hydrolysis resistance, electrical properties, and product life. It is particularly used in electrical applications, can be employed (after suitable preparation) in cold-cure systems, and shows high affinity to glass fibre. DAP can also be used as a reactive plasticizer with PVC resins. 

Polymers resistant to hydrolysis in all media include polyolefins, hydrocarbon rubbers, polystyrene, polytetrafluoroethylene, and implasticized poly(vinyl chloride). Polymers sensitive to hydrolysis in both alkaline and acidic media are, eg, cellulose esters, plasticized poly(vinyl chloride), polyCmethyl methacrylate), polyacrylonitrile, polyoxymethylene, polyamides, polyesters, polycarbonates, and polysulfones. Polymers sensitive to alkalis but not acids are imsaturated polyester resins and phenol-formaldehyde resins. 

The hydroxy-functional polyurethane dispersions can be cross-linked with MF resins or blocked isocyanates. Blocked isocyanates can also be used with water-reducible anionic acrylic or polyester resins instead of an MF resin oxime blocked isocyanates are commonly used, owing to their high reactivity. Oxime blocked aliphatic isocyanates are more stable to hydrolysis than oxime blocked aromatic isocyanates (32). As mentioned earlier alcohol blocked isocyanates are used in cationic electrodeposition coatings. 

Pastes are stored in mildly agitated stainless steel (304 L, 316 L) tanks. Polyester resins form suitable tank coatings when only mild steel tanks are available. Copper and its alloys may cause discolouration of the product and should be avoided. Temperatures below 15 should be avoided and therefore heating coils with warm water (40°C) are required. Ehiring storage, solutions of alcohol ether sulphate often tend to become acidic due to hydrolysis. Ways to prevent this have been described in section 6.5.3. and 6.6.4., storage and handling of primary alcohol sulphates. 

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