Document 5kRD2Zk4xEmmm0LN7JOmo9KBe

INTERNAL CORRESPONDENCE ) CC- JCK CHEMICALS AND PLASTICS To<Nm) See Attached Distribution Division Chemicals & Plastics Location Copy to Dr. W. P. Gorham-BB/98 Mr. D. E. Heywood-NY/ DECEIVED * RIVER ROAD. BOUND BROOK. NEW JERSEY 08806 APR 19 1978 April 17, 1978^- W. LASHER Orlftnating Dtpt. Ancwtrint ittur data Sublet DRAFT PROTOCOL ON PVC STUDIES FOR SUBMISSION TO FDA Attached is a first draft of a protocol for our PVC resin studies which is intended for submission to the FDA. We would appreciate any additions, corrections, changes, etc., which you may care to make. Please make changes directly on your copy and return to me. UJ a W. B. Ackart WBA:cu Attachments UCC 029893 UNION CARBIDE CORPORATION CHEMICALS AND PLASTICS RIVER ROAD, BOUND BROOK, N. J. 0SI03 TELEPHONE 1201) 306-0000 1978 Hearing Clerk Food and Drug Administration Dept, of Health, Education, and Welfare Room 4-65 5600 Fishers Lane Rockville, MD 20852 DOCKET NO. 75N-0190 NOTICE OF PROPOSED RULE MAKING RE: VINYL CHLORIDE POLYMERS IN CONTACT WITH FOODS Dear Sir: Union Carbide believes and is preparing to demonstrate that food contact films and coatings made with its solution polymerized vinyl resins contain no detectable quantities of vinyl chloride monomer. Therefore, we believe there is no reasonable expectation that foods contacting such films or coatings will be contaminated with vinyl chloride monomer, we have instituted analytical programs and mathematical modeling to support this premise. Union Carbide, a manufacturer of solution polymerized vinyl coatings resins for 45 years, operates a unique process which continuously polymerizes vinyl chloride and comonomers in a solvent and produces a clear solution of resin in a solvent. This solution is then distilled to remove unconverted vinyl chloride monomer. The dis tilled resin solution is filtered, and residual monomer is further extracted by a second solvent. The resin is then precipitated with water and is recovered by filtration, washed and dried. After drying, the resin typically contains less than 0.2 ppm residual vinyl chloride, which unt'il recently was the limit of sensitivity of our analytical procedure. UCC 029894 2- - In the can coating process, resins are usually applied by airless spray technique from a 20 to 25 percent total solids solution in a mixture of solvents. The coated container is then passed through a high velocity air oven at ^320*F to remove solvents. For taste considerations it is essential that virtually no solvents remain in the coating. Normal coating weights range from 4 to 7 mg/in2 with a thickness of about 0.25 mils. Calculations by us and others indicate that residual vinyl chloride monomer in the cured coating will be nil. /VY)n Our experimental program will include the following: 1. Develop the capability of measuring concentrations of vinyl chloride monomer in resins, resin solutions, resin coatings, and cured resin coatings of a sensitivity of a few parts per billion (ppb). We have found that the analytical procedure currently recommended by the Food and Drug Administration specifies operat ing temperatures at which available sampling syringes do not func tion properly. Further, the solvent used in sample preparation frequently contains impurities which mask the vinyl chloride res-_._--r-- ponse. However, we 's'blTTtlons to these and other problems/uau and will -be fuu-nd, thus leading to a--mere^satisfactory t analytical procedure. 2. Collect data for production blends of our solution-polymerized vinyl chloride-vinyl acetate copolymers and modified vinyl chloridevinyl acetate copolymers at the bagging pointf^as shipped to our customers showing residual vinyl chloride monomer at the ppb level. ***"5 L-- .'Em 3. Collect data for cured coatings (on metal substrates) prepared from solution-polymerized vinyl resins. Initial mathematical modeling of coatings'* systems, taking into account the evaporation and baking cycles, leads us to believe that residual vinyl chloride monomer will be below the detectable (ppb) levefr A feasible method; of obtaining a sufficiently large resin sample (20 g specified) from thin coatings (^5 mg/sq in) remains to be developed. 4. Collect data under conditions simulating various steps in the coating operation which will enable the construction of mathematical equations predicting the theoretical concentration of vinyl chloride monomer in the cured coating (the food contact surface). For example, we propose to measure vinyl chloride monomer in solid resin, in a coating solution as prepared, at various stages of evaporation, in a dry but uncured coating, and in a dried cured coating. We believe the theoretical maximum concentration in the food contact surface will be far below the level of sensitivity of the analytical method. UCC 02989s 3 5. Collect data under conditions still to be determined to test the theory which has been proposed--that there is a limit below which residual vinyl chloride monomer cannot be removed from poly vinyl chloride resins, and hence will not reasonably be expected to migrate to foods. 6. Although solution-polymerized vinyl resins are marketed for use in can<eo5e&gs'pJsA;^fTaf3?',6^Bifese polymers have physical properties that would enable their use in rigid films and sheetings and/or extruded pipe for potable water. As an extension of the present study we propose to determine residual monomer levels in experimental sheet and pipe fabricated from these low monomer resins. This laboratory program is in progress. Although we have experi enced difficulties with the analytical procedure we believe that a reasonable target date for completion of the proposed study is mid--summer of 1978. u<i( mt it,.. Very truly yours, , -jj;- t_, ^ 'CK. - f ` 6.''uyt S 4 y K* 1 .Z >* ,t * , 'A*.. W. B. Ackart, PhD Manager, FDA Liaison < WBA:cu 15a-A-26 cc: Dr. K. J. Felci Div. of Chemistry & Physics Bureau of Foods Food and Drug Administration 200C Street SW Washington, DC 20204 entire ''iu.*<tiTi-i ^ UCC 029896 DISTRIBUTION Dr. L. E. Brydia-BB/200 Mr. T. B. Gibb-BB/200 Dr. R. A. Gregory-BB/203 Mr. J. G. Kucsma-NY/33 R. W. Lasher-NY/33 Mr. J. V. Murray-NY/46 Mr. G. S. Peacock-BB/98 Dr. K. R. Szoc-BB/203 Mr. R. N. Wheeler-SC Dr. F. G. Willeboordse-BB/98 ucc 029897