Cellulose plastics esters

From 1980 to 1988, aimual cellulose acetate flake production in the United States showed a slight decrease in production from 392,000 t to 323,000 t with an aimual decline of —0.4 to —0.1% (Table 6). World demand for cellulose acetate flake has also fallen. A modest recovery has occurred in recent years as a result of the increased demand for cigarette-filter tow world consumption of cigarette-filter tow has risen about 2.5% per year since 1980 (Tables 7 and 8). In contrast, world demand for textile fibers and cellulose ester plastics decline 4.6% and 4.2% per year, respectively (Fig. 9). 

Cellulose acetate ester plastics are produced largely in the United States, Western Europe, and Japan. World consumption is assumed to be approximately equivalent to production of cellulose ester plastics in these three regions. Courtesy of CEH Estimates. 

The Chemical Daily Company, Ltd., Tokyo, Japan, 1982, p. 95 K. Wheeler, W. Cox, and N. Takei, Cellulose Picetate and Cellulose Ester Plastics, CEH Marketing Research Report, SRI International, Menlo Park, Calif., Apr. 1989. 

Uses. Plasticizer for cellulose ester plastic films and sheets in molded plastics manufacturing varnishes cosmetics... 

Cellulose esters are used as plastics for the formation by extrusion of films and sheets and by injection molding of parts. They are thermoplastics and can be fabricated employing most of the usual techniques of (largely compression and injection) molding, extrusion, and casting. Cellulose ester plastics are noted for their toughness, smoothness, clarity, and surface gloss. 

BUTYRATE PLASTICS. See Cellulose Ester Plastics (Organic). 

Cellulose dissolves in Schweitzer s reagent, an ammoniacal solution of cupric oxide. After treatment with an alkali, ibe addition of carbon disulfide causes formation of sodium xanihate. a process used in the production of rayon. Sec also Fibers. The action of acetic anhydride in the presence of sulfuric acid produces cellulose acetates, the basis for a line of synthetic materials. See also Cellulose Ester Plastics (Organic). Nitrocelluloses are produced hy ihc action of nitric acid and sulfuric acid on cellulose, yielding compounds that are highly flammable and explosive. See also Explosives. 

CELLULOSE ESTER PLASTICS (Organic). The cellulosics are unique among the plastics in that the basic materials used in theiv manufacture are not synthetic polymers. Rather, they are derivatives of a natural polymer, cellulose. Sec also Cellulose. The preparation of an organic cellulose ester plastic involves the formation of a suitable cellulose derivative, fallowed by processing steps that convert the cellulose derivative into a plastic. 

Although Lhe first cellulose plastic (cellulose nitrate plastic-based on an inorganic ester of cellulose) was developed in 1865. the first organic cellulose ester plastic was not offered commercially until 1927. In that year, cellulose acetate plastic became available as sheets, rods, and tubes. Two years later, in 1929. it was offered in the form of granules for molding. It was the first thermoplastic sufficiently stable to be melted without excessive decomposition, and it was the first thermoplastic to be injection molded. Cellulose acetate butyrate plastic became a commercial product in 1938 and cellulose propionate plastic followed in 1945. The latter material was withdrawn after a short time because of manufacturing difficulties, but it reappeared and became firmly established in 1955. 

Since the cellulose esters CA. CAB, and CP are chemical raw materials, the won plastic was used in the preceding paragraph to differentiate the product from the raw material. The cellulose ester plastics are commonly called simply "acetate. butyrate." and "propionate." and these names will be used in the text that follows. 

In the manufacture of cellulose ester plastic, the appropriate ester is blended with plasticizer and other additives, such as stabilizers, ultraviolet inhibitors, dyes, and pigments, commonly in a large sigma-blade mixer. The mixture thus obtained is heated to its softening temperature and kneaded until it is homogeneous. This is done on hot milling rolls, in a compounding extruder, or in a Banbury mixer. The molten mass of plastic that results is formed into small rods or strips that are then cut into cylindrical or cubical pellets, which ordinarily have dimensions of about J inch (3 millimeters). See Fig. 2. 

All three cellulose ester plastics are available in formulutions that meet the regulatory requirements for use in contact with food. 

The organic cellulose ester plastics are versatile materials and can be processed by almost any hot-processing technique used for thermoplastics. The principal techniques for all three plastics are injection molding and extrusion. Blow molding is also possible. Butyrate and propionate powder are used in tluidized-bed and electrostatic coating processes, as well as in the rotational molding process. 

The derivatives arc hydroxycthyl and hydroxypropyl cellulose. All four derivatives find numerous applications, and there are other reactants that can be added to cellulose, including the mixed addition of reactants leading to adducts of commercial significance. See also Cellulose Ester Plastics (Organic). 

DEP is used as a plasticizer to make plastics more flexible. Commonly found in products such as toothbrushes, automobile parts, tools, toys, and food packaging. Also used as a plasticizer in solid rocket propellants and cellulose ester plastics such as photographic films and sheets, blister packaging, and tape applications. 

Use Solvent mix for cellulose esters, plasticizing mix for cellulose esters. 

Uses Flame retardant plasticizer for plastics incl. rigid PU and polyisocyanurate foams, PVC, carpet backing, flame-laminated and rebonded flexible foam, coatings, most thermosets, adhesives, cast acrylic sheet, wood-resin composites (particle board) fire-resist, cellulose ester plasticizer in food-pkg. adhesives Regulatory FDA 21CFR 175.105... 

Isoamyl butyrate Phenoxyethanol plasticizer, cellulose acetate lacquers Dimethyl phthalate plasticizer, cellulose acetate, nitrate 2-Nitro-1,1 -biphenyl plasticizer, cellulose compounds N,N-Butyl benzene sulfonamide plasticizer, cellulose ester N-(2-Hydroxypropyl) benzenesulfonamide plasticizer, cellulose ester plastics Dihexyl phthalate... 

Cellulose, whose repeat structure features three hydroxyl groups, reacts with organic acids, anhydrides, and acid chlorides to form esters. Plastics from these cellulose esters are extruded into film and sheet and are injection molded to form a wide variety of parts. Cellulose esters can also be compression molded and cast from solution to form a coating. The three most industrially important cellulose ester plastics are cellulose acetate (CA), cellulose acetate butyrate (CAB), and cellulose acetate propionate (CAP), with structures as shown in Fig. 2.2. 

Chemists at Leverkusen were familiar with cellulose ester plastics and poly 2,3-dimethylbutadiene rubber, but these were produced on a small scale without the benefit of a knowledge of macromolecular chemistry. The production of Buna S, which was a copolymer of butadiene and styrene, which was aa laboratory curiosity. In spite of opposition from influential members of Ae board of directors of I.G. Farben-industrie, Bayer directed the development of a process for the production of styrene monomer and polystyrene at the Ludwigshafen and Bitterfield plants. 

Allergic and irritant contact dermatitis to various additives are briefly mentioned in connection with various plastics by other authors. In spite of the fact that phthalates are the most widely used additives, there are only a few reports in the literature of contact dermatitis caused by phthalates. Allergic contact dermatitis from dibutyl phthalate has been reported when used in a plastic watch strap, an anti-perspirant spray and a steroid cream [1-4]. Contact dermatitis from diethyl phthalate has been reported from spectacle frames, and a hearing aid was reported to cause contact dermatitis from cellulose-ester plastics [5, 6]. Two cases of contact allergy to the dimethyl phthalate in computer mice have been reported by Capon et al. [7]. 

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. 

L. Bottenbruch fed.). Polycarbonate, Polyacetal, Polyester, Cellulose Ester, Plastics Handbook 3/1, Hanser Publishers, Munich, Vienna, 1992 fin German). 

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