[Code of Federal Regulations]
[Title 21, Volume 3]
[Revised as of April 1, 2001]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR177.1550]
[Page 284-286]
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. 177.1550 Perfluorocarbon resins.
Perfluorocarbon resins identified in this section may be safely used
as articles or components of articles intended to contact food, subject
to the provisions of this section:
(a) Identity. For the purpose of this section, perfluorocarbon
resins are those produced by: (1) The homopolymerization and/or
copolymerization of hexafluoropropylene and tetrafluoroethylene, and (2)
the copolymerization of perfluoropropylvinylether and
tetrafluoroethylene (CAS Reg. No. 26655-00-5). The resins shall meet the
extractives limitations in paragraph (d) of this section.
(b) Optional components. The perfluorocarbon resins identified in
paragraph (a) of this section as well as articles or coating made from
these resins may include the following optional components except that
the resin identified in paragraph (a)(2) of this section may not be used
with the optional component, lithium polysilicate, mentioned in
paragraph (b)(4) of this section.
(1) Substances generally recognized as safe (GRAS) in food or food
packaging subject to any limitations cited on their use.
(2) Substances used in accordance with a prior sanction or approval,
subject to any limitations cited in the prior sanction or approval.
(3) Substances authorized under applicable regulations in this part
and in parts 175 and 178 of this chapter and subject to any limitations
prescribed therein.
(4) The following substances, subject to any limitations prescribed:
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List of substances Limitations
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Lithium polysilicate containing not more For use only as a component
than 20 weight percent silica, not more of repeated-use coatings
than 2.1 percent lithium oxide and having not exceeding 0.030
a maximum mole ratio of Si02/Li20 of 8.5 millimeter (0.0012 inch) in
to 1. thickness where the
coatings are thermally
cured at minimum sintering
temperatures of 371 deg.C
(700 deg.F). Lithium
extractives shall not
exceed 1.55 milligrams per
square decimeter (0.1
milligram per square inch)
of coating surface when
tested in accordance with
paragraph (e)(2) of this
section.
Naphthalene sulfonic acid formaldehyde For use only:
condensate, sodium salt. 1. As a component of
repeated-use coatings,
based on the
perfluorocarbon resin
identified in paragraph
(a)(1) of this section, not
to exceed 0.030 millimeter
(0.0012 inch) in thickness,
and at a level not to
exceed 0.4 weight percent
of the coating.
2. As a component of
repeated-use coatings,
based on the
perfluorocarbon resin
identified in paragraph
(a)(2) of this section, not
to exceed 0.10 millimeter
(0.004 inch) in thickness,
and at a level not to
exceed 0.4 weight percent
of the coating.
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(c) Optional processing. Poly- tetrafluoroethylene resins may be
irradiated by either a cobalt-60 sealed source, at a maximum dose of
gamma radiation not to exceed 7.5 megarads, or an electron beam at
energy levels not to exceed 2.5 million electron volts with a maximum
dosage of 7.5 megarads, to produce lubricant powders having a particle
diameter of not more than 20 microns for use only as components of
articles intended for repeated use in contact with food.
(d) Specifications--(1) Infrared identification. Perfluorocarbon
resins can be identified by their characteristic infrared spectra.
(2) Melt-viscosity. (i) The perfluorocarbon resins identified in
paragraph (a)(1) of this section shall have a melt viscosity of not less
than 104 poises at 380 deg.C (716 deg.F) as determined by
ASTM
[[Page 285]]
method D1238-82, ``Standard Test Method for Flow Rates of Thermoplastics
by Extrusion Plastometer,'' which is incorporated by reference. Copies
may be obtained from the American Society for Testing Materials, 1916
Race St., Philadelphia, PA 19103, or may be examined at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC 20408. The melt viscosity of the perfluorocarbon resins
identified in paragraph (a)(1) of this section shall not vary more than
50 percent within one-half hour at 380 deg.C (716 deg.F).
(ii) Perfluorocarbon resins identified in paragraph (a)(2) of this
section shall have a melt viscosity of not less than 10\4\ poises at 372
deg.C (702 deg.F) as determined by a more detailed method titled
``Determination of Melt Viscosity, Molecular Weight Distribution Index
and Viscosity Stability,'' which is incorporated by reference. Copies
are available from the Center for Food Safety and Applied Nutrition
(HFS-200), Food and Drug Administration, 200 C St. SW., Washington, DC
20204, or available for inspection at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC
20408.
(3) Thermal instability index. The thermal instability index of the
tetrafluoroethylene homopolymer shall not exceed 50 as determined by
ASTM method D1457-56T, ``Test for Thermal Instablility index of
Tetrafluoroethylene Homopolymer'' (Revised 1956), which is incorporated
by reference. Copies are available from University Microfilms
International, 300 N. Zeeb Rd., Ann Arbor, MI 48106, or available for
inspection at the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC 20408. The requirements of this
paragraph do not apply to polytetrafluoroethylene resin lubricant
powders described in paragraph (c) of this section.
(e) Limitations. \1\ (1) Perfluorocarbon-molded articles having a
surface area of 6.45 square decimeters (100 square inches) or more and
at least 1.27 millimeters (0.05 inch) thick shall be extracted at reflux
temperatures for 2 hours separately with distilled water, 50 percent
ethanol, n-heptane, and ethyl acetate.
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\1\ A more detailed procedure of extraction conditions is entitled,
``Preparation of Extracts,'' which is incorporated by reference. Copies
are available from the Center for Food Safety and Applied Nutrition
(HFS-200), Food and Drug Administration, 200 C St. SW., Washington, DC
20204, or available for inspection at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC
20408.
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(2) Perfluorocarbon resins identified in paragraphs (a)(1) and (2)
of this section and intended for use as coatings or components of
coatings shall meet extractability limits prescribed in paragraph (e)(3)
of this section when the resins in the form of coatings described in
paragraphs (e)(2) (i) and (ii) of this section are extracted at reflux
temperatures for 2 hours separately with distilled water, 8 percent
ethanol, and n-heptane:
(i) Perfluorocarbon resin coatings based on resins identified in
paragraph (a)(1) of this section shall be applied to both sides of a
0.025-millimeter (0.001 inch) thick aluminum foil to a thickness of
0.025 millimeter (0.001 inch) after thermal curing at 399 deg.C (750
deg.F) for 10 minutes. If a primer is used, the total thickness of the
primer plus topcoat shall equal 0.025 millimeter (0.001 inch) after heat
curing.
(ii) Perfluorocarbon resin coatings based on resins identified in
paragraph (a)(2) of this section shall be applied to both sides of a
0.025-millimeter (0.001 inch) thick aluminum foil to a thickness of 0.10
millimeter (0.004 inch) after thermal curing at 427 deg.C (800 deg.F)
for 10 minutes. If a primer is used, the total thickness of the primer
plus topcoat shall equal 0.10 millimeter (0.004 inch) after heat curing.
(3) The extracted surfaces shall meet the following extractability
limits:
(i) Total extractives not to exceed 3.1 milligrams per square
decimeter (0.2 milligram per square inch).
(ii) Fluoride extractives calculated as fluorine not to exceed 0.46
milligram per square decimeter (0.03 milligram per square inch).
(f) Conditions of use. Perfluorocarbon resins identified in
paragraph (a)(2) of
[[Page 286]]
this section are limited to use as coatings or components of coatings
for articles intended for repeated food-contact use.
[43 FR 44834, Sept. 29, 1978, as amended at 47 FR 11843, Mar. 19, 1982;
47 FR 14699, Apr. 6, 1982; 49 FR 10109, Mar. 19, 1984; 50 FR 1502, Jan.
11, 1985; 54 FR 24898, June 12, 1989; 61 FR 14481, Apr. 2, 1996]