Document QMJ99k6XwGGnggj4gMJj85Bj8

/W-/A57 SjJCiJ.L 'tment of I and the ` i ation of t 'luring mixing I control "ii is the air. n issued mi nation t weekly v para- II other mixers ^ion of a formed ' exit tea/ r< mtided f hloinl A" |,hVrogram of the "'ok on t were "omuls -forase riskier- `eviollS ii land re has [053, d and 'g and -tickles -cn] (<! - com- (racts <Te. ntiallv VINYL PLASTICS Their Dermatological and Chemical Aspects GEORGE E. f MORRIS, M.D. BOSTON DURING the past 12 years there has been a fivefold increase in the number of dermatoses caused by the chemicals used in the manufacture of plastics.1 New plastics are being developed each year, and it is necessary that the industrial phy sician and dermatologist know the fundamentals of the chemistry of the different plastics, so that he will be able to judge correctly any case that comes to him for judgment concerning causal relationship with the work. I The patient knows little about his job except that he uses "raw stock" or "over| lay" decorative, that he "spreads vinyl onto cloth" or that he "dips a plastic pencil i into a solvent known as MKK." The examining physician should know what the 1 chemical of the `Taw stock" can he.- He should know something about the chemistry of the vinyls and should have a speaking acquaintance with such things as MEK t (methylethyl ketone). TCP (tricresyl phosphate), DOP (dioctyl phosphate), etc. j Plastics, in general, may be divided into five groups or classes: 1 1. Condensation 2. Vinyl (or polymerization) 3. Cellulose 4. Synthetic rubbers 5. Miscellaneous Polymerization resins may be divided into six groups: 1. Polyvinyl resins 2. Polyacrylate resins 3. Potyvinylidene resins 4. Polyethylene resins 5. Polystyrene resins ' 0. Coumarone and indene resins j Polymerization is the chemical union of two or more molecules of a substance to I form a new compound without the elimination of a secondary compound. A monomer j is a substance consisting of a single part; a dimer is a substance consisting of two 1 parts, etc. - h, Morris is Assistant Clinical Professor of Dermatology, Tufts College Medical School, j 1. Morris, G. 1C: Condensation Plasties: Their Dermatological and Chemical Aspects. * {A- M. A. Arch. fnd. Hyg. 5:37-43 (Jan.) 1952. I 535 j { 20497001 4.^.4. w tbfi t Occ^p tAtd BpG03658 536 INDUSTRIAL HYGIENE AND OCCUPATIONAL MEDICINE The polymerization resins are almost always compounded with other ingredients to produce the finished plastics. Compounding ingredients include plasticizers, stabi lizers, pigments and dyes, lubricants, and fillers. POLYVINYL RESINS2 Vinyl resins contain the vinyl linkage, --CH* -- CHX. X must be a strongly negative group--chloride, acetate, butyrate, alcohol, or acetal. Vinyl chloride monomer CH = CH Acetylene + HC1-------------------------------- > CH2=CHC1 Hydrochloric acid Vinyl chloride CHj = CHC1 Heat Pressure----*-- CHs -- CH -- Catalyst | CHs --CH -- Cl -- CHa-- CH -- Cl Copolymers Vinyl chloride polymer CH, rr CHC1 CH* = CHOCOCHa Vinyl chloride 80-98% Vinyl acetate 2-20% -CH* -CH --CH* - CH -- CH* -- CH -- CH*-- CH -- CH* II Cl Cl O-C--0-CH3 Cl Polyacrylat derivatives: CH? = t CHs = > CH, = * CH, = < Methyl Acryla CH, CN-- CH Ethylene c; The polyn The trade coatings, lead. Only a fe\ Motion Polymerix It is often vinyl chlorid- Dermatitis in a coater of vinyl plastics. The more vinyl acetate that is used, the more soluble is the product and so the more useful for coatings (see "Flow Chart''). The trade names include Yinylite, (jcuu, Koroseal, Saflex, Marvinol, etc. They are used as moulding compounds, adhe sives, fabrics, cable coverings, floor tile, belts, raincoats, toys, etc. I have not seen any eruption from the finished product, but the Figure shows an eruption from vinyl latex used for coating artificial leather. 2. Shreve, R. N.: Chemical Process Industries, New York, McGraw-Hill Book Company, Inc,, 1945. The trade no covers, pipe. Cracked pc o 03 The trade na -4 of blown but O cable insulat BFG03659 MORRIS--VINYL PLASTICS 5 37 POLYACRYLATE RESINS Polyacrylate resins are formed from the polymerization of acrylic acid and its derivatives: CIIa=CHCOOH CIIs= CHCOOCHj CHj= C(CH;,)COOH CH, = C(CI-I3)COOCHj Acrylic acid Methyl acrylate Mcthacrvlic acid Methyl methacrylate Methyl Acrylate Polymerization Cracking Petroleum------ process-------------------------------- * CHa = CH Ethylene ch2 = ch. HiO Cl CH.CL CH.OH + NaCN Ethylene chlorohydrin CHaCN-- CHsOH + CHaOH - catalyst CHiCHOCOCH* Ethylene cyanohydrin Methanol The polymer is --CHS -- CII-- [CH,-CH],, -- CH= -- CH / 0 = C --OCH, !I O -- C -- OCH, 0 --C--OCH, The trade names are Plexiglas and Lucite. They are used as dentures, adhesives, coatings, leather finishes, optical novelties, etc. Only a few cases of stomatitis have been seen from acrylic dental plates. POLYVIN YLIDENE RESINS Monomer--vinylidene chloride C1I2 =C Uj Polymerizes ci r ci "i Cl ! -CH*-- C -- CH* -- C -- CH, --C -- Cl a It is often copolymerized with vinyl chloride (10% vinylidene chloride and 90% vinyl chloride). H Cl H Cl -t 1 I H 1 C11 l H 1 Ci1 ! Hi! Cii l -C t 1 --C i -- Ci1 -- C 1 -- Ci1 -- C i1 -- C 1 -- C ! -- c-- 1 . H H H Cl H Cl H Cl H H . The trade name is Saran. It is used in the manufacture of upholstery fabrics, seat covers, pipe, tubes, battery cases, belts, suspenders, etc. POLYETHYLENE RF.SINS r HHHH Cracked petroleum- CH,= CHaIvlhyU'iie Pressure -C--C--C-C-- l1 I I H H H H Ju Polyethylene The trade names are Polythene and DYNF Resin. The resins are used in the form of blown bottles, tubing, tape, sheeting, film, and tor packaging, tableware, wire and cable insulation, molded closures, etc. BFG03660 538 INDUSTRIAL HYGIENE AND OCCUPATIONAL MEDICINE Occasional sensitization to these resins occurs, especially in workers coating the resins before complete polymerization has occurred. POLYSTYRENE RESINS Polymerizes as follows: Vinyl r A and H ma\ D ma> CH, -- Cl The trade names are Lustron, Lustre*, Polystyrene, Styramic and Plexene. They are used as bottles, jars, closures, tableware, toilet articles, wall tile, brushes, etc. COUMARONE AND INDENE KESTNS These are coal tar derivatives. CO CO CHj The polymerization is similar to that of styrene. The trade names are Cumar, NeviJlac, and Nypene. These are used for coatings, varnishes, printing inks, tile, rubber compounding, and chewing gum. The compounds added to the resins include plasticizers, stahtiiztrs, lubricants, colorants and fillers. Plasticizers are chemicals which render the finished product more plastic. They make tip 10% to 50% of the weight of the finished product. They include the follow ing: phosphates (tricresyl phosphate--TCP); phthalates (dioctyl phtlulate-- DUP) ; ricinoleic acid derivatives; sebacic acid derivatives; azelates; polyesters; nitrile rubbers; petroleum derivatives; chlorinated aromatic hydrocarbons. Stabilizers arc substances which prevent decomposition from heat and sunlight. They make up 2 to 5% by weight. They include lead compounds (basic white lead carbonate and basic white lead silicate) ; tin compounds, epoxides, phosphates, and metallic soaps. Lubricants are added to plastics and make for ease of flow (internal and exter nal). They include fatty acids, waxes, oils, and metallic soaps. The colors used include dyes and pigments. 37illers are added to confer chemical resistance, mechanical strength, electrical properties, and thermal resistance. The mineral fillers are commonly used and include clays, mica, asbestos, limestone, and diatomaceous earth. BFG03661 20497004 CHr~C-- (< CH, CH, CO CC The pi for shipna tization d  ng the They vs, etc. N'evil< ithher iarnts. They i< illow- . date-- .inters; -alight, le lead and cxterused rctrical ' 1 and MORRIS--I'l.VYL PLASTICS 539 SUMMARY Vinyl resins are formed hv the polymerization of nh II -C=C--D BH r j; -c--c-- AD bh I! C--C II AD AH I1 -C-C- Ii BD A and H are preferably hydrogen, occasionally FI or Cl. H may he hydrogen, Cl, F, CM, or CH;i. U mav he hydrogen or COOH, Cl, F, CN, COOR, CHs, --- O--R,-- CHu. CH* -- CH CH.-C-- (CH.) CH. I'll, CCX CC1 H CaHo Cl OR 0 COCHa F COOH CN COOH COOCHa CN Cl CN Ethylene Styrene Vinyl chloride Vinyl ether Vinyl acetate Vinyl fluoride Acrylic acid Acrylonitrile Methacrylic acid Methyl methacrylate Vinylidene cyanide Vinylidene chloride Chloroacrylonitrile The polymerization resins are handled by enclosed processes until they are ready tor shipment. Workers handling the partially polymerized resins may develop sensi tization dermatitis. Eruptions caused by the finished products are rare but do occur. * 20497005 BFG03662