§177.1960 氯乙烯/1-己烯共聚物(Vinyl chloride-hexene-1 copolymers)

　　§177.1960 Vinyl chloride-hexene-1 copolymers.


　　The vinyl chloride-hexene-1 copolymers identified in paragraph （a） of this section or as components of articles intended for use in contact with food, under conditions of use D, E, F, or G described in table 2 of § 176.170（c） of this chapter, subject to the provisions of this section.

　　（a） Identity. For the purposes of this section vinyl chloride-hexene-1 copolymers consist of basic copolymers produced by the copolymerization of vinyl chloride and hexene-1 such that the finished copolymers contain not more than 3 mole-percent of polymer units derived from hexene-1 and meet the specifications and extractives limitations prescribed in paragraph （b） of this section. The copolymers may optionally contain hydroxypropyl methyl-cellulose and trichloroethylene used as a suspending agent and chain transfer agent, respectively, in their production.

　　（b） Specifications and limitations. The vinyl chloride-hexene-1 basic copolymers meet the following specifications and extractives limitations:

　　（1） Specifications. （i） Total chlorine content is 53 to 56 percent as determined by any suitable analytical procedure of generally accepted applicability.

　　（ii） Inherent viscosity in cyclohexanone at 30 °C is not less than 0.59 deciliters per gram as determined by ASTM method D1243-79, “Standard Test Method for Dilute Solution Viscosity of Vinyl Chloride Polymers,” which is incorporated by reference. Copies may be obtained from the American Society for Testing Materials, 100 Barr Harbor Dr., West Conshohocken, Philadelphia, PA 19428-2959, or may be examined at the National Archives and Records Administration （NARA）. For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

　　（2） Extractives limitations. The following extractives limitations are determined by the methods prescribed in § 177.1970（d）.

　　（i） Total extractives do not exceed 0.01 weight percent when extracted with water at 150 °F for 2 hours.

　　（ii） Total extractives do not exceed 0.30 weight percent when extracted with n -heptane at 150 °F for 2 hours.

　　（c） Other specifications and limitations. The vinyl chloride-hexene-1 copolymers identified in and complying with this section, when used as components of the food-contact surface of any article that is subject to a regulation in parts 174, 175, 176, 177, 178 and § 179.45 of this chapter, shall comply with any specifications and limitations prescribed by such regulation for the article in the finished form in which it is to contact food.

　　[42 FR 14572, Mar. 15, 1977, as amended at 49 FR 10110, Mar. 19, 1984]