Document k4QKGyx8JEy2p7wz74b6NKmO

Ati' mi tment of I and tlie II ation of 't during mixing; I control 1 m is the ar. ii issued initiation t weekly "v paraii other mixers ssinti of 'in irnied > critical rounded t Mood .co phvrncr.'ini ' cil the ook on "t were rounds 'U*rase n.-ider- "eviolis n land re has 195.1, d and 'g and ticides aapcd - com(racts utiallv vlfS to I'livnn! VINYL PLASTICS Their Dermatological and Chemical Aspects GEORGE E. | 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 I 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 he able to judge correctly any case that comes to him for judgment concerning causal relationship with the work. j The patient knows little about his job except that he uses "raw stock" or "over j 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 , 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. j Plastics, in general, may he divided into five groups or classes: | ( j 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. Polyvinylidene resins 4. Polyethylene resins i 5. Polystyrene resins ; 0. Coumarone and indene resins * Polymerization is the chemical union of two or more molecules of a substance to j form a new compound without the elimination of a secondary compound. A monomer f is a substance consisting of a single part; a dimer is a substance consisting of two *i parts, etc. In. Morris is Assistant Clinical Professor of Dermatology, Tufts College Medical School. | 1. Morris, G. hi.: Condensation Plastics: Their Dermatological and Chemical Aspects, ^"a. M. A. Arch. Ind. Hyg. 5:37-43 (Jan.) 1952. 535 ifrcA t Occ^-p tA<-d If- 535-53*11 BpG03658 20497001 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, -- CH2 = CHX. X must be a strongly negative group--chloride, acetate, butyrate, alcohol, or acetal. Vinyl chloride monomer CH s CH Acetylene + HC1-------;------------------------- CH,= CHC1 Hydrochloric acid Vinyl chloride CH, = CHC1 + Copolymers Heat Pressure----*-- CH, -- CH -- Catalyst | Cl CH, --CH -- 'I Cl -CH,-- CH- I Cl Vinyl chloride polymer Polyacrylai derivatives: CH,= i CH, = i CHj= ' CH, = > Methyl Acryla CH, CN-- CH Ethylene c; The polyn The trade coatings, lead Only a fe\ Monou Polymeriz It is often vinyl chloric!' 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 Vinylite, (jeon, Koroseal, Satlex, 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. Siireve, R. X.: Chemical Process Industries, New York, McGraw-Hill Book Company, Inc., 1945. The trade na covers, pipe, Cracked pi o CD The trade na of blown bot O cable insula! BFG03659 bents -tabi'"gly die l!C, . le an MORRIS-VINYL PLASTICS 537 polyacrylate resins Polyacrylate resins are formed from the polymerization of acrylic acid and its derivatives: CH, = CHCOOH CI1,= CHCOOCH, CH,= C(CH;,)COOH CH,:=C(CH,)COOCH, Acrylic acid Methyl acrylate Methacrylic acid Methyl methacrylate Methyl Acrylate Polymerization Cracking Petroleum------ process -> CH, = CH, Ethylene H,0 CHi = CH, -------------------- Cl CHiCL CH,OH + NaCN - Ethylene chlorohydrin catalyst CH, CN-- CH,OH + CHaOH--------------------------------- CH,CHOCOCH, Ethylene cyanohydrin Methanol The jtolymer is --CH, --CH--[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 lew cases of stomatitis have been seen from acrylic dental plates. POLYVINYLIDENE RESINS Monomer--vinylidene chloride C1L* = C Cl2 Polymerizes Cl Cl --CH,--C -- CH, -- C -- i Cl CH, Cl I CI Cl It is often copolymerized with vinyl chloride (10% vinylidene chloride and 90% vinyl chloride). H Cl H Cl H Cl H Cl H Cl - I1 CI1 -- 1I CI1 -- /| C - JI c1( - | c 1 - If c11 -- )1 c 11 - 11 c11 i1 - 1 c 1 - 11 c 11 -- . 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. POLYETII YLENE RI'.S! NS Cracked petroleum Heat CH,= CH,---------------------- Ethylene Pressure HHHH II I i --C--C--c--c-- II ! 1 HHH H J Polyethylene The trade names are Polythene and DYNF 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. BFG03660 20497003 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 >-CH = CH, * CH, -CH;->rj^^S|-CH;CH, EihyWn* r CHCHj + H2 Polymerizes as follows: -CH2- CJH-CHj-CH-CHj-CH-- 'J'he trade names are Lustron, Lustrex, Polystyrene, Styramic and Plexene. They are used as bottles, jars, closures, tableware, toilet articles, wall tile, brushes, etc. COUMARONE AND INDENE RESINS These are coal tar derivatives. Ogj The polymerization is similar to that of styrene. The trade names are Cumar, Nevillac, and Nypene. These are used for coatings, varnishes, printing inks, tile, rubber compounding, and chewing gum. The compounds added to the resins include plasticizers, stabilizers, lubricants, colorants and fillers. Plasticizers are chemicals which render the finished product more plastic. They make.up 10% to 50% 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 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. 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 diatomaceous earth. BFG03661 Vinyl r A and H nia\ D mat CH, -- Cl CH.--C--(< CH. CO CH. CC The pi for shipnn tization d< o X 3 2 inf' the 1'hey i'k, etc. Mevil> nbber ncants, They 11 illow- date-- esters; mdight. :te lead "s, and : exteri's used metrical d and MORRIS--1'INYL PLASTICS 539 SUMMARY Vinyl resins are formed by the polymerization of RH II A--C=C--D BH r -C-C-- II AD BH I! c--c 1I AD AH II -C-C-- II BD A and B are preferably hydrogen, occasionally FI or Cl. H may be hydrogen, Cl, F, CM, or CH:i. D mav he hydrogen or COOH, Cl, F, CM, COOR, CnH5, -- O--R, -- CH;{. CH, -- CH CH,--C--(CH,) CH, Clb CCX CC1 H C.H. Cl OR O COCH, F COOH CN COOH COOCH, CN Cl CN Ethylene Styrene Vinyl chloride Vinyl ether Vinyl acetate Vinyl fluoride Acrylic acid Acrylonitrile Methacrylic acid Methyl methacrylate Vjnylidene 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. 20497005 BFG03662