Document e51wyVNjZ4wMk52Lpwb6q32qp

Mr. M. E. Eisenhour Texas City (515) See Attached List Pern 1974 H WHE1'1 * , ?. O. EOX 3361, SOUTH CHARLESTON, WEST VIRGINIA 25303 October 10, 1974 VC1 Monomer in Vinyl Solution Resins Dear Merle In a recent letter, Russ Hanna discussed the inter ference observed from acetaldehyde in the VC1 monomer analysis f polymer latexes containing vinyl chloride and vinyl acetate; this observation indicates a need to develop a modified method, parti cularly for use with systems in which the acetaldehyde is an interfering volatile material. To put the data developed on the vinyl solution resins in proper perspective, the following should be considered: 1. In data reported on vinyl solution resins indicating <1.5 ppm 4 of vinyl chloride no significant interference from acetaldehyd in the vinyl chloride peak was detected. Thus, these results are valid. 2. The question does remain in the recently reported high values of apparent VC1 noted in recent samples of the VMCC resin. These are the only vinyl solution resin samples in which an apparent interference of acetaldehyde has been noted. These observations lead to the following conclusions and suggestions: 1. It is unlikely that a single method will suffice for the determination of vinyl chloride monomer in PVC, vinyl solution resins and in polymer latexes, though this will be a goal of a revision of the method. 2. As you know, analysis of other retained blends of VMCC resin and of other vinyl solution resins is in progress at the Plant Laboratories. We suggest that this program be continued with the present method. The results, if they show >1.5 ppm of VC1 will establish if the acetaldehyde interference noted with th VMCC resin is an isolated case. Values showing <1.5 ppm are valid. ucc 068462 i Mr. M. E. Eis nhour Page 2 October 10, 1974 3. Recent preliminary studies by A1 Gabany of the samples of VMCC . resin under question indicate that with a change of columns able to resolve the VC1 and acetaldehyde peaks, no VC1 monom r was detected in the VMCC samples, while a definite peak for acetaldehyde was observed. 4. Thus, the statement that no detectable VC1 monomer (1.5 ppm lower level of detectability) is present in vinyl solution resins is still valid and the current method is technically sound when acetaldehyde interference is not present. Obviously, a modification of the current method is re quired to provide quantitative definition of VC1 monomer in th presence of acetaldehyde, to remove this complication from con sideration. I An important objective of the revision of the present method and modified method will be to establish that the lower i level of VC1 detectability is 1.0 ppm (or less, if possible). This is necessary as the new FDA standard will indicate 1.0 ppm maximum VC1 monomer in the food contacting surface. We anticipate no significant problem in reducing the level to 1.0 ppm. If there are any questions regarding these comments, please feel free to contact me. Regards, Q.iLfa H. John Brezanski JJB:pw WW < JWrV' : \.y ifJ M'AWI *w UCC 068463 fc*