[Code of Federal Regulations]
[Title 21, Volume 3]
[Revised as of April 1, 2005]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR177.1560]

[Page 301]
 
                        TITLE 21--FOOD AND DRUGS
 
CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN 
                          SERVICES (CONTINUED)
 
PART 177_INDIRECT FOOD ADDITIVES: POLYMERS--Table of Contents
 
Subpart B_Substances for Use as Basic Components of Single and Repeated 
                        Use Food Contact Surfaces
 
Sec. 177.1560  Polyarylsulfone resins.

    Polyarylsulfone resins (CAS Reg. No. 79293-56-4) may be safely used 
as articles or components of articles intended for use in contact with 
food, at temperatures up to and including normal baking temperatures, in 
accordance with the following prescribed conditions:
    (a) Identity. Polyarylsulfone resins are copolymers containing not 
more than 25 percent of oxy-p-phenylene-oxy-p-phenylenesulfonyl-p-
phenylene polymer units and not less than 75 percent of oxy-p-
phenylenesulfonyl-p-phenylene-oxy-p-phenylenesulfonyl-p-phenylene 
polymer units. The copolymers have a minimum reduced viscosity of 0.40 
deciliter per gram in 1-methyl-2-pyrrolidinone in accordance with ASTM 
method D2857-70 (Reapproved 1977), ``Standard Test Method for Dilute 
Solution Viscosity of Polymers,'' which is incorporated by reference. 
Copies may be obtained from the American Society for Testing and 
Materials, 1916 Race St., Philadelphia, PA 19103, 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.
    (b) Optional adjuvant substances. The basic polyarylsulfone resins 
identified in paragraph (a) of this section may contain optional 
adjuvant substances required in the production of such basic copolymers. 
These optional adjuvant substances may include substances permitted for 
such use by regulations in parts 170 through 179 of this chapter, 
substances generally recognized as safe in food, substances used in 
accordance with a prior sanction of approval, and substances named in 
this paragraph and further identified as required:

------------------------------------------------------------------------
            Substances                           Limitations
------------------------------------------------------------------------
Sulfolane.........................  Not to exceed 0.15 percent as
                                     residual solvent in the finished
                                     basic resin.
------------------------------------------------------------------------

    (c) Extractive limitations. The finished polyarylsulfone resin when 
extracted for 2 hours with the following solvents at the specified 
temperatures yields total extractives in each extracting solvent not to 
exceed 0.008 milligram per square centimeter of food-contact surface: 
distilled water at 121 [deg]C (250 [deg]F), 50 percent (by volume) ethyl 
alcohol in distilled water at 71.1 [deg]C (160 [deg]F), 3 percent acetic 
acid in distilled water at 100 [deg]C (212 [deg]F), and n-heptane at 
65.6 [deg]C (150 [deg]F).

    Note: In testing the finished poly aryl sulfone resin use a separate 
test sample for each required extracting solvent.

[50 FR 31046, July 24, 1985]