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177.2400 Perfluorocarbon cured elastomers.

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[Code of Federal Regulations]
[Title 21, Volume 3]
[Revised as of April 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR177.2400]

[Page 336-337]
                        TITLE 21--FOOD AND DRUGS
                          SERVICES (CONTINUED)
Subpart C_Substances for Use Only as Components of Articles Intended for 
                              Repeated Use
Sec.  177.2400  Perfluorocarbon cured elastomers.

    Perfluorocarbon cured elastomers identified in paragraph (a) of this 
section may be safely used as articles or components of articles 
intended for repeated use in contact with nonacid food (pH above 5.0), 
subject to the provisions of this section.
    (a) Identity. (1) For the purpose of this section, perfluorocarbon 
cured elastomers are produced by terpolymerizing tetrafluorethylene (CAS 
Reg. No. 116-14-3), perfluoromethyl vinyl ether (CAS Reg. No. 1187-93-
5), and perfluoro-2-phenoxypropyl vinyl ether (CAS Reg. No. 24520-19-2) 
and subsequent curing of the terpolymer (CAS Reg. No. 26658-70-8) using 
the crosslinking agent, phenol, 4,4'-[2,2,2-trifluoro-1-
(trifluoromethyl) ethylidene] bis-,dipotassium salt (CAS Reg. No. 25088-
69-1) and accelerator, 1,4,7,10,13,16-hexaoxacyclooctadecane (CAS Reg. 
No. 17455-13-9).
    (2) The perfluorocarbon base polymer shall contain no less than 40 
weight-percent of polymer units derived from tetrafluoroethylene, no 
less than 40 weight-percent of polymer units derived from 
perfluoromethyl vinyl ether and no more than 5 weight-percent polymer 
units derived from perfluoro-2-phenoxy-propyl vinyl ether.
    (3) The composition limitations of the cured elastomer, calculated 
as parts per 100 parts of terpolymer, are as follows:

 Phenol, 4,4'-[2,2,2-trifluoro-1-(trifluoromethyl)-ethylidene] bis-
,dipotassium salt--not to exceed 5 parts.
1,4,7,10,13,16-Hexaoxacyclo-octadecane--not to exceed 5 parts.

    (b) Optional adjuvant substances. The perfluorocarbon cured 
elastomer identified in paragraph (a) of this section may contain the 
following optional adjuvant substances, subject to any limitations cited 
on their use:
    (1) Substances generally recognized as safe (GRAS) in food or food 
    (2) Substances used in accordance with a prior sanction.
    (3) Substances authorized under applicable regulations in this part 
and in parts 175 and 178 of this chapter and

[[Page 337]]

subject to any limitations prescribed therein.
    (4) Substances identified in this paragraph (b)(4) subject to such 
limitations as are provided:

                Substances                           Limitations
Carbon black (channel process of furnace    Not to exceed 15 parts per
 combustion process) (CAS Reg. No. 1333-86-  100 parts of the
 4).                                         terpolymer.
Magnesium oxide (CAS Reg. No. 1309-48-4)..  Not to exceed 5 parts per
                                             100 parts of the

    (c) Specifications--(1) Infrared identification. Perfluorocarbon 
cured elastomers may be identified by the characteristic infrared 
spectra of the pyrolysate breakdown product that is obtained by heating 
and decomposing the elastomer using the method entitled ``Qualitative 
Identification of Kalrez [reg] by Infrared Examination of 
Pyrolysate.'' This method is incorporated by reference. Copies of the 
method are available from the Center for Food Safety and Applied 
Nutrition (HFS-200), Food and Drug Administration, 5100 Paint Branch 
Pkwy., College Park, MD 20740, or available for inspection 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:
    (2) Thermogravimetry. Perfluorocarbon cured elastomers have a major 
decomposition peak occurring at 490 [deg] 15 
[deg]C (914 [deg]F). Less than 1.5 percent of the elastomers will 
volatilize below 400 [deg]C (752 [deg]F) when run under nitrogen at a 10 
[deg]C or 18 [deg]F per minute heating rate using a Du Pont Thermal 
Analyzer Model 1099 with Model 951 TGA unit or the equivalent.
    (d) Extractive limitations. Articles fabricated from perfluorocarbon 
cured elastomers having a thickness of at least 1.0 millimeter (0.039 
inch) when extracted at reflux temperatures for 2 hours separately with 
distilled water, 50 percent ethanol, and n-heptane, shall meet the 
following extractability limits:
    (1) Total extractives not to exceed 3.1 milligrams per square 
decimeter (0.2 milligrams per square inch).
    (2) Fluoride extractives calculated as fluorine not to exceed 0.47 
milligram per square decimeter (0.03 milligram per square inch).
    (e) Conditions of use. In accordance with current good manufacturing 
practice, finished food contact articles containing the perfluorocarbon 
cured elastomers shall be thoroughly cleaned prior to their first use in 
contact with food.

[49 FR 43050, Oct. 26, 1984]

Additives that reference this regulation:

Source: U.S. Code of Federal Regulations - CFR Title 21, Part 177, Section 2400

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