Document oeZvDQGj2w2Yy37bzR8YyGdND

I -1# ' /c -jr` f -te<*` by caw*Wt law (Title u u.S, Cod#).| j * / .- - _ __ _Y1NYt_ PLASTICS TMr Dsrmotological md Chemical Aspect* " ______ GEORGE t MORRIS, M.O. OSTON DURING the past 12 years there lias been a fivefold increase in the number of dermatoses caused by the chemicals used in the manufacture of plastics*1 New plastics o.'e.beli.g 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. The patient knows little about bis job except that he uses "raw stock" or "over lay" decorative, that he "spreads vinyl onto cloth" or that he "dips a plastic pencil into a solvent known as MEK." The examining physician should know what the chemical of the "raw stock" can be. He should know something about the chemistry of the vinyls and should have a speaking acquaintance with such things as MEK (methylethyl ketone), TCP (tricresyl phosphate), DOP (dioctyl phosphate), etc. Plastics, mineral, may*be divided into five groups or classes: 1. Condensation Z Vinyl (or polymerization) 3. Cellulose 4, Synthetic rubber* 5. Miscellaneous Polymerization resins may be divided into six groups: I. Polyvinyl resins Z "Polyacrylate resine 3. Polyvinyltdene resin* 4. Polyethylene min* 3. Polystyrene min* & Conmarooe and indent mine APolymerization is the chemical union of two or more molecules of a substance to form a new compound without the elimination of a secondary compound. monomer is a substance consisting of a single part; a dimer is a substance consisting of two parts, etc. Dr. Morris is Assistant Clinical Professor of Dermatology, Tufts College Medical School. 1. Morris, C. E.: Condensation Plastics: Their Dermatological and Chemical Aspects. A^M. A. Arch. Ind. Hyg. 3:37-43 (Jan.) 19SZ 535 W' s <1 meMgiwe" ii.'.'.u.www ucc 006465 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 RESINS * Vinyl resins contain the vinyl linkage, -- CHa -- CHX. X must be a strongly negative group--chloride, acetate, butyrate, alcohol, or acetal. Vinyl chloride monomer CHaCH Acetylene + HQ---------------------------- - CH,=sCHCl Hydrochloric acid Vinyl chloride CH. = CHC1 + Heat Pressure---- CH. -- CH -- CH. --CH -- LcH.--CH -- Catalyst d. di I i Copolymers Vinyl chloride polymer CH. = CHCI CH. = CHOCOCH. Vinyl chloride 80-98% Vinyl acetate 2-20% -- CH, -- CH -- CH. -- CH -- CH.--CH -- CH.-- CH -- CH. T dlCl O-C--O-CH. <~1 , 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 Virrylite, Geon, 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 fro'm the finished product, but the Figure shows an eruption from vinyl latex used for coating artificial leather. `i 2. Shreve, R. X.: Chemical Process Industries, New York, McGraw-Hill Book Company, Ior., 19-I5. /" ~ ucc 006466 CH,= CI-ICOOII CHj= CHCOOCH. CH.= C(CH,)COOH '' ~CH= = C (CH,) COOCH. Acrylic acid Methyl acrylate Methacrylic acid " Methyl methacrylate MethyPAcrylate Polymerization . _____ Cracking Petroleum------ process- --------------- CH, = CH, Ethylene CH, = CH, H,0 Cl CHsCL CH,OH + NaCN Ethylene chlorohydrin CH, CK-- CH.OH + CH.OH- catalyst CH^HOCOCH. ' Ethylerfe tyanohydrin Methanol The polymer is- ` --CH, -- CH-- [CH,-- CHJ. -- CH, --CH 0 d= C --OCH, O --C --OCH, O -- --OCH, The trade names are Plexiglas and I. ucite, They ate used as der.utes, adhesives, coatings, leather finishes, optical novelties, etc. Only a few cases of stomatitis have been seen from acrylic dental plates. POLYVINYLIDENE RESINS Monomer--vitiylidene chloride __ CH, -- C Cl, Polvmerizes ar --ch,--i- ci i di It is often copolymerized with vinyl chloride (10% vinylidene chloride and 90% vinyl chloride). r a H at H H Cl H Cl 11 CI h ~ -L-fc- -A -t- t -d- c - c - A -- At ciVx |1 LH ii ii H a11 i1 H di i H i i_ The trade name is Saran. It is used in the manufacture of upholstery fabrics, seat covers, pipe, tubes, battery cases, belts, suspenders, etc. POLYETHYLENE RESINS Cracked petroleum - >CH,= CH,F.thylene ___ Pressure ' HHHH Polyethylene The trade names arc Polythene and DYXF Resin. The resins are used in the form of blown bottles, tubing, tape, sheeting, film, and for packaging, tableware, wire and cable insulation, molded closures, etc. ucc 00646*? 538 INDUSTRIAL HYGIENE AND OCCUPATIONAL MEDICINE Occasional sensitization to these resins occurs, especially in- workers coating the resins before complete polymerization has occurred. --" Styrene POLYSTYRENE RESINS Polymerizes as follows: The trade names are Lustron, Lustrex, Polystyrene, Styramic and PJexene. They are used as bottles, jars, closures, tableware, toilet articles, wall tile, brushes, etc. COUilARONE AND IKDENE RESINS These are coal tar derivatives. The polymerization is siu.i.at to that of styrene. The trade name; are Cumar, NevilTac, and Nypene. These are used for coatings, varnishes, printing inks^tile, rubber compounding, and chewing gum. The compounds added to the resins iodude plasticizers, stabilizers, lubricants, colorants and fillers, ' ~- Plasticizers are chemicals which render the finished product more' plastic. They make up 10^> to 50<fo of the weight of the finished product. They include the follow ing: phosphates (tricresyl phosphate--TCP); phthalates (dioctyl phthalate-- DOP); ricinoleic acid derivatives; sebacic acid derivatives; azelates; polyesters ; nitrile rubbers; petroleum derivatives; chlorinated aromatic hydrocarbons. Stabilizers are substances which prevent decomposition from'heat and sunlight. They make up 2 to 5% hy 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. Fillers 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 diatoniaceous earth. ucc 006468 MORRIS--I'lSYL PLASTICS -- _ __ SUMMARY Vinyl resins are formed by the polymerization of -B H I I- 1 -A--C=C--D BH 539 A and Bare preferably hydrogen, occasionally FI or Cl. H may be hydrogen. Cl, F, CN, or CH,. D may be hydrogen or COOH, Cl, F, CN, COOR, CaH,, -- O--R, -- CH,. CH, -- CH CHI CCN CH, - CQ-, Ethylene Styrene Vinyl chloride Vinyl ether Vinyl acetate Vinyl fluoride Acrylic acid crylonitrile Methacrylic acid Methyl methacrylate Vinylidene cyanide Vinylidene chloride Chloroacrylonitrile The polymerization resins are handled by enclosed processes until they are ready for shipment. Workers handling the partially polymerized resins may develop sensi tization dermatitis. Eruptions caused by the finished products are rare but do occur. ucc 006469