Polyesters structurally colored

The structure—N/C-coated cellophane/polyethylene/aluminum foil/ adhesive/50ga polyester/adhesive/polyethylene—had a shelf life of over 6-9 months with no moisture, flavor, or color loss. This barrier system contained the product successfully (see Table IV). 

There is a wide diversity of chemical structures of anthraquinone colorants. Many anthraquinone dyes are found in nature, perhaps the best known being alizarin, 1,2-dihydroxyanthraquinone, the principal constituent of madder (see Chapter 1). These natural anthraquinone dyes are no longer of significant commercial importance. Many of the current commercial range of synthetic anthraquinone dyes are simply substituted derivatives of the anthraquinone system. For example, a number of the most important red and blue disperse dyes for application to polyester fibres are simple non-ionic anthraquinone molecules, containing substituents such as amino, hydroxy and methoxy, and a number of sul-fonated derivatives are commonly used as acid dyes for wool. 

In order to facilitate satisfactory dye uptake, the molecular size of a disperse dye must be kept small monoazo structures are therefore exceptionally important, particularly in the coloration of polyester and cellulose triacetate. In the yellow shade area, molecular size generally poses no problem and the various available coupling components can all be used without making the molecule too large. A very simple example of the type of structure employed using a phenolic coupling component is Cl Disperse Yellow 3 (4-72). This dye is known to cause skin sensitisation when on nylon [85] and can also provoke an allergic reaction [86]. 

Iso-phthalic polyester resin was corroded with the formation of the color changed surface layer and corrosion rate of the resin were controlled by diffusion process of the solution through the layer. Thus similar behavior was observed to oxidation corrosion of metal obeying Wagner s parabolic law. The difference of behaviors of these resins were mainly due to the position of ester bonds in the structures. 

The structural chemistry of alkyds has already been covered in Chapter 15, Section 7. Although there are over 400-500 varieties of such resins, they are all polyesters with carbon-carbon double bonds that can be cross-linked. They are very versatile in coatings, and their diverse properties can be matched for particular uses. They are the most widely used resins for protective coatings. Their best points can be summarized as follows (1) easy to apply (2) can have flat, semigloss, or high-gloss finish (3) useful for most surfaces except concrete or plaster (alkaline) (4) good color retention and (5) odorless (some of them). 

DuPont and Shell have developed a new polyester, poly(trimethylene terephthalate) (PTT) (structure 19.38) that is structurally similar to PET, except that 1,3-propanediol (PDO) is used in place of ethylene glycol. The extra carbon in Sorona allows the fiber to be more easily colored giving a textile material that is softer with greater stretch. Further, it offers good wear and stain resistance for carpet use. The ready availability of the monomer PDO is a major consideration with efforts underway to create PDO from the fermentation of sugar through the use of biocatalysts for this conversion. Sorona and Lycra blends have already been successfully marketed. Sorona is also targeted for use as a resin and film. 

Gel coats are pigmented polyester coatings applied to the mold surface and are an integral part of the finished laminate. Gel coats are used widely on hand lay-up and spray-up parts to enhance surface aesthetics and coloration as well as to provide an abrasion-resistant waterproof surface that protects the underlying glass-reinforced structure. 

These dyes are the backbone of most commercial dye ranges. Based entirely on benzene and naphthalene derivatives, they provide yellow, red, blue, green, and black colors for all the major substrates such as polyester, cellulose, nylon, polyacrylonitrile, and leather. Typical structures are (79)—(84). 

A different class of polycyclic naphthoquinone dyes is based on the n apht h 12,361 i ndolizine -6,11 -dione system 14, which is readily accessible by condensation of 2,3-dichloro-l,4-naphthoquinone with active methylene compounds in the presence of pyridine [22], or by reaction of 2-methoxy-3-pyridino-1,4-naphthoquinone with an active methylene compound [23], In 14, the bridgehead nitrogen atom acts as an effective auxochrome, and hence orange to red colors are observed without further substitution. Derivatives of 14 (R = amide group) are of particular value as vat dyes and pigments. Related isomeric heterocyclic structures have also attracted interest, e.g., 15, a yellow disperse dye for polyester [24],... 

The high temperature stability of direct dyes is an important consideration if one wishes to use these dyes as the colorant for cotton when dyeing a polyester/cotton blend at 130°C.20 The key to success is to choose dyes that are resistant to hydrolysis. Suitable dyes include C.I. Direct Yellow 105, C.I. Direct Orange 39, and C.I. Direct Blue 80, whereas unsuitable dyes include C.I. Direct Yellow 44, C.I. Direct Red 80, and C.I. Direct Red 83. A quick examination of the structures... 

According to DuPont, the structure of the fibre molecule gives Sorona materials improved characteristics. For example, Sorona makes a softer fibre than either polyester or nylon while still offering other desirable attributes like superior comfort-stretch, recovery and dyeability. The fibre also allows manufacturers to use up to three different dye methods to create a single fabric with many different colors in a pattern. Sorona fibre also enables fibre to be dyed at lower temperatures than either polyester or nylon. 

A number of poly (thiol esters) have been synthesized by method BC (29). The reaction temperature was increased from room temperature to above 200°C. The products were often colored because of side reactions (replacement of hydroxyl with chlorine, formation of ketene structures, and ester pyrolysis are known side reactions in polyester formation). 

Urethane resins are synthesized from isocyanates and chemical compounds with hydroxyl or urethane groups (—N—C—O—) including water, polyesters, epoxies, and acrylics [8,9]. The chemical structure of urethane coating is shown in Fig. 13.4. Polyester and epoxy have better barrier resistance to moisture and chemical attack than the acrylic polyol. Ahphatic isocyanate-based coatings are resistant to UV hght and have excellent gloss and color retention. 

The anthraquinone dyes are based on the structure shown in Figure 4. Key properties are summarized in Table 3. Most commercial anthraquinone dyes have sufficient heat stability to be used in polycarbonate and thermoplastic polyesters. However, as indicated in Table 3, only a handful of these dyes are suitable for polyamide Figure 4. The anthraquinone resins and their blends and alloys. Even in these cases caution must ring system. applied. Polyamide materials colored with red anthraquinone... 

Polyester multi-spiral yarn fabrics of specific collocation structures is shown Fig.6 in contrast to color developed sections of the butterfly s scales. The fabrics with contrasts of deep color shades and lusters emphasize silhouettes of clothings, and are appreciated as the fabric materials of higher grade. 

The fine concave and convex structure is formed by a difference of solubility against alkali between potyester fibers and the particles uniformly dispersed in polyester fibers. The potyester fiber of fine concave and convex structure, Micro crater fiber-SN2000 , provides not only a deeper color shade,but an improvement of luster,a dissolution of glittering under direct rays(for a particular use in the artificial hair), a color brightness of printed fabrics,modifications of hand and handle of fabrics. 

---