Polyester Saturated

Polyols. Several important polyhydric alcohols or polyols are made from formaldehyde. The principal ones include pentaerythritol, made from acetaldehyde and formaldehyde trimethylolpropane, made from -butyraldehyde and formaldehyde and neopentyl glycol, made from isobutyraldehyde and formaldehyde. These polyols find use in the alkyd resin (qv) and synthetic lubricants markets. Pentaerythritol [115-77-5] is also used to produce rosin/tall oil esters and explosives (pentaerythritol tetranitrate). Trimethylolpropane [77-99-6] is also used in urethane coatings, polyurethane foams, and multiftmctional monomers. Neopentyl glycol [126-30-7] finds use in plastics produced from unsaturated polyester resins and in coatings based on saturated polyesters. 

Phthahc anhydride (1) is the commercial form of phthaUc acid (2). The worldwide production capacity for the anhydride was ca 3.5 x 10 metric tons ia 1993, and it was used ia the manufacture of plasticizers (qv), unsaturated polyesters, and alkyd resins (qv) (see Polyesters, unsaturated). Sales of terephthahc acid (3) and its dimethyl ester are by far the largest of any of the benzenepolycarboxyhc acids 14.3 x 10 t were produced in 1993. This is 80% of the total toimage of ah. commercial forms of the benzenepolycarboxyhc acids. Terephthahc acid is used almost exclusively for the manufacture of poly(ethylene terephthalate), which then is formed into textiles, films, containers, and molded articles. Isophthahc acid (4) and trimehitic anhydride (5) are commercial products, but their worldwide production capacities are an order of magnitude smaller than for terephthahc acid and its dimethyl ester. Isophthahc acid is used primarily in the production of unsaturated polyesters and as a comonomer in saturated polyesters. Trimehitic anhydride is used mainly to make esters for high performance poly(vinyl chloride) plasticizers. Trimesic acid (6), pyromehitic dianhydride (7), and hernimehitic acid (8) have specialized commercial apphcations. The rest of the benzenepolycarboxyhc acids are not available commercially. 

Purified terephthalic acid and dimethyl terephthalate are used as raw materials for the production of saturated polyesters. During 1993, the combined worldwide production of purified terephthafic acid plus dimethyl terephthalate exceeded 14 x 10 t (42), which is 80% of the total benzenepolycarboxyfic acid production. Terephthafic acid is also produced ia technical or cmde grades which are not pure enough for manufacture of poly(ethylene terephthalate). In almost all cases, the technical-grade material is immediately converted to purified terephthafic acid or dimethyl terephthalate, which together are the articles of commerce. 

Like terephthalic acid, isophthalic acid is used as a raw material in the production of polyesters. Much of the isophthaUc acid is used for unsaturated polyesters, whereas terephthaUc acid is used almost exclusively in saturated (thermoplastic) polyesters. However, a considerable amount of isophthaUc acid is used as a minor comonomer in saturated polyesters, where the principal diacid is terephthaUc acid. The production volume of isophthaUc acid is less than 2% that of terephthahc. IsophthaUc acid was formerly produced in technical or cmde grades and only a small amount was purified. Now, however, it is all purified to a standard similar to that of terephthahc acid. 

The third, and fastest growing, area of isophthahc acid use is in other types of polymers, primarily as a minor comonomer with terephthahc acid in saturated polyesters. Over 20% of the isophthahc acid is sold in this apphcation. One rapidly expanding use is in polyester beverage bottles where addition of up to 3% isophthahc acid to the terephthahc acid allows faster production of more complex shapes. In this way, single piece bottles can be made, vs a round-bottomed bottle that needs a separate base cup. Fibers are also modified with isophthahc acid. 

Powder coatings are formulated from the reaction product of trimethylolpropane and IPDI, blocked with caprolactam, and polyester polyols. The saturated polyester polyols are based on aromatic acid diols, neopentyl glycol, and trimellitic anhydride for further branching. To avoid the release of caprolactam in the curing reaction, systems based on IPDI dimer diols are used. 

Plasticizers can be classified according to their chemical nature. The most important classes of plasticizers used in rubber adhesives are phthalates, polymeric plasticizers, and esters. The group phthalate plasticizers constitutes the biggest and most widely used plasticizers. The linear alkyl phthalates impart improved low-temperature performance and have reduced volatility. Most of the polymeric plasticizers are saturated polyesters obtained by reaction of a diol with a dicarboxylic acid. The most common diols are propanediol, 1,3- and 1,4-butanediol, and 1,6-hexanediol. Adipic, phthalic and sebacic acids are common carboxylic acids used in the manufacture of polymeric plasticizers. Some poly-hydroxybutyrates are used in rubber adhesive formulations. Both the molecular weight and the chemical nature determine the performance of the polymeric plasticizers. Increasing the molecular weight reduces the volatility of the plasticizer but reduces the plasticizing efficiency and low-temperature properties. Typical esters used as plasticizers are n-butyl acetate and cellulose acetobutyrate. 

Thermoplastic, linear and saturated polyester give, depending on their chemical composition, hard or elastic and tacky bond lines they have relatively high melting viscosities bond lines are resistant against moisture, water and UV. 

After a de-nib, spray surfacer is applied to build up the film thickness before top-coating. The surfacer contains a high level of pigment and extender (at least 35% by volume) and frequently a saturated polyester resin with a melamine —or urea —formaldehyde crosslinker. The coating is applied at thicknesses up to 35 ftm and stoved for 20 min at 150-165°C. 

For this use, the preferred powders are based on acrylic, epoxy or polyester and epoxy resins. For best colour, epoxy resins are crosslinked with anhydrides of dicarboxylic acids in the straight epoxy coatings, or with saturated polyesters of high acid content in the epoxy-polyester type. Acrylics contain epoxide rings via, for example, glycidyl methacrylate (CH2=C(CH3) —CO—O—CHj—CH —CH2), and these groups crosslink... 

Unsaturated polyesters are similar to the saturated polyesters shown in Section 14.9, but include maleic anhydride or fumaric acid to introduce unsaturation ... 

Saturated polyesters and saturated alkyds cannot undergo such modification with vinyl monomers but can be modified with other polymers such as silicone resins by alcoholysis. Here outdoor durability is considerably improved. 

Polyester-based networks are typically prepared from polyester prepolymers bearing unsaturations which can be crosslinked. The crosslinking process is either an autoxidation in the presence of air oxygen (alkyd resins) or a copolymerization with unsaturated comonomers in the presence of radical initiators (unsaturated polyester resins). It should also be mentioned that hydroxy-terminated saturated polyesters are one of the basis prepolymers used in polyurethane network preparation (see Chapter 5). 

Progress in Rubber and Plastics Technology 16, No.l, March 2000, p.61-8 CHEMICAL RECYCLING OF WASTE SATURATED POLYESTERS AND URETHANE POLYMERS TO YIELD RAW MATERIALS FOR THE PRODUCTION OF POLYURETHANES Kacperski M Spychaj T Szczecin,Polytechnic... 

Teehniques are reviewed for the ehemical recycling of waste saturated polyesters (PETP and PBTP), and of waste... 

CHEMICAL RECYCLING OE WASTE SATURATED POLYESTERS AND URETHANE POLYMERS TO YIELD RAW MATERIALS FOR THE PRODUCTION OF POLYURETHANES... 

Techniques for chemical recycling of waste saturated polyesters, mainly poly(ethylene terephthalate) and of waste polyurethanes to produce polyurethanes are reviewed. 29 refs. Articles from this journal can be... 

RECYCLING OF INJECTION-MOULDED POLYURETHANE SCRAP IN THE PRODUCTION OF SATURATED POLYESTER RESINS... 

For studying the emulsifying properties, saturated polyesters can be used to avoid complications by the reactivity of unsaturated units of the EUP [117]... 

Saturable dye absorber, 14 677 Saturated aqueous salt solution, 9 34 Saturated calomel electrode (SCE), 9 571 Saturated fatty acids, 10 829, 830 Saturated hydrocarbons adsorbent affinity, 1 674 adsorption by zeolites, 1 624 fluorine reactivity with, 11 831 isomerization of, 12 172—173 Saturated polyester resins, based on trimethylpentanediol, 12 673 Saturated polyesters, 10 7 Saturated synthetic rubber, 10 705 Saturation and coating processes, 10 12-13 Saturation bonding, 17 509-510 Saturation color, 19 262 Saturation concentration, 15 677 Saturation index... 

Linear saturated polyesters of low Molecular weight (less than 10,000) can be obtained by condensing a diol with a diacid. Molecular weight can be controlled by adding a monohydric alcohol or monocarboxylic acid. These polymers are used as plasticisers or as polyester diols for making polyurethanes. 

Practically all the polymers can be processed to make nanocomposites. This emerging technology is developing in polyamide andTPO nanocomposites with applications in the automotive industry, and there are experiments with saturated polyesters, acrylics, polystyrenes... 

The best performing coatings were the vinyl ester, the bisphenol A epoxy cured with an aliphatic amine, and a novolac epoxy cured with a mixed aromatic/cycl oal i phati c amine. The saturated polyester, and a bisphenol A epoxy cured with a polyamide amine showed significant deterioration of the coating material in the acid, and corrosion of the underlying steel. Two types of novolac epoxies cured with aromatic amines showed intermediate performance. 

Anderson E. Freeman, Characterization of Saturated Polyesters by Differential Thermal Analysis , AnalChem 31, 1697 (1959)... 

Unsaturated polyesters do not, in general, seriously affect the reactivity of a variety of explosives and propellants. Similarly, saturated polyesters do not affect reactivity of explosives and propellants significantly. 

ABS = Acrylonitrile Butadene Styrene PA = Polyamide PAN = Polyacrylonitrile PBT = Polybbutylene Terephthalate PE= Polyethylene PET = Polyethylene Terephthalate PP = Polypropylene PUR = Polyirethane PVC = Polyvinyl chloride UPE = Un saturated polyester XPE = Cross-linked polyethylene ... 

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