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173.21 Perfluorinated ion exchange membranes.

Home > Regulations > Secondary direct food additives permitted in food for human consumption > 173.21 Perfluorinated ion exchange membranes.



[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: 21CFR173.21]

[Page 121-122]
 
                        TITLE 21--FOOD AND DRUGS
 
CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN 
                          SERVICES (CONTINUED)
 
PART 173_SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN 
CONSUMPTION--Table of Contents
 
  Subpart A_Polymer Substances and Polymer Adjuvants for Food Treatment
 
Sec.  173.21  Perfluorinated ion exchange membranes.

    Substances identified in paragraph (a) of this section may be safely 
used as ion exchange membranes intended for use in the treatment of bulk 
quantities of liquid food under the following prescribed conditions:
    (a) Identity. The membrane is a copolymer of ethanesulfonyl 
fluoride, 2-[1-[difluoro-[(tri fluoro ethenyl) oxy] methyl]-1,2,2,2-
tetra fluoro ethoxy]-1,1,2,2,-tetra fluoro-, with tetra fluoro ethylene 
that has been subsequently treated to hydrolyze the sulfonyl fluoride 
group to the sulfonic acid. The Chemical Abstracts Service name of this 
polymer is ethane sulfonic acid, 2-[1-[difluoro-[(tri fluoro 
ethenyl)oxy] methyl]-1,2,2,2-tetra fluoro ethoxy]-1,1,2,2,-tetra fluoro-
, polymer with tetra fluoro ethane (CAS Reg. No. 31175-20-9).
    (b) Optional adjuvant substances. The basic polymer identified in 
paragraph (a) of this section may contain optional adjuvant substances 
required in the production of such basic polymer.

[[Page 122]]

These optional adjuvant substances may include substances used in 
accordance with Sec.  174.5 of this chapter.
    (c) Conditions of use. (1) Perfluorinated ion exchange membranes 
described in paragraph (a) of this section may be used in contact with 
all types of liquid foods at temperatures not exceeding 70[deg] (158 
[deg]F).
    (2) Maximum thickness of the copolymer membrane is 0.007 inch (0.017 
centimeter).
    (3) Perfluorinated ion exchange membranes shall be maintained in a 
sanitary manner in accordance with current good manufacturing practice 
so as to prevent microbial adulteration of food.
    (4) To assure their safe use, perfluorinated ionomer membranes shall 
be thoroughly cleaned prior to their first use in accordance with 
current good manufacturing practice.

[59 FR 15623, Apr. 4, 1994]





Additives that reference this regulation:


Source: U.S. Code of Federal Regulations - CFR Title 21, Part 173, Section 21


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