[Code of Federal Regulations]
[Title 21, Volume 3]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR177.1950]
[Page 324-326]
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. 177.1950 Vinyl chloride-ethylene copolymers.
The vinyl chloride-ethylene copolymers identified in paragraph (a)
of this section may be safely used as components of articles intended
for contact with food, under conditions of use D, E, F, or G described
in table 2 of Sec. 176.170 (c) of this chapter, subject to the
provisions of this section.
(a) For the purpose of this section, vinyl chloride-ethylene
copolymers consist of basic copolymers produced by the copolymerization
of vinyl chloride and ethylene such that the finished basic copolymers
meet the specifications and extractives limitations prescribed in
paragraph (c) of this section, when tested by the methods described in
paragraph (d) of this section.
(b) The basic vinyl chloride-ethylene copolymers identified in
paragraph (a) of this section may contain optional adjuvant substances
required in the production of such basic copolymers. The optional
adjuvant substances required in the production of the basic vinyl
chloride-ethylene copolymers may include substances permitted for such
use by regulations in parts 170 through 189 of this chapter, substances
generally recognized as safe in food, and substances used in accordance
with a prior sanction or approval.
(c) The vinyl chloride-ethylene basic copolymers meet the following
specifications and extractives limitations:
(1) Specifications. (i) Total chlorine content is in the range of 53
to 56 percent as determined by any suitable analytical procedure of
generally accepted applicability.
(ii) Intrinsic viscosity in cyclohexanone at 30 [deg]C is not less
than 0.50 deciliter 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 described in paragraph (d) of this
section:
(i) Total extractives do not exceed 0.10 weight-percent when
extracted with n-heptane at 150 [deg]F for 2 hours.
(ii) Total extractives do not exceed 0.03 weight-percent when
extracted with water at 150 [deg]F for 2 hours.
(iii) Total extractives obtained by extracting with water at 150
[deg]F for 2 hours contain no more than 0.5 milligram of vinyl chloride-
ethylene copol-ymer per 100 grams of sample tested as determined from
the organic chlorine content. The organic chlorine content is determined
as described in paragraph (d)(3) of this section.
(d) Analytical methods: The analytical methods for determining
whether vinyl chloride-ethylene basic copolymers conform to the
extractives limitations prescribed in paragraph (c) of this section are
as follows and are applicable to the basic copolymers in powder form
having a particle size such that 100 percent will pass through a U.S.
Standard Sieve No. 40 and 80 percent will pass through a U.S. Standard
Sieve No. 80:
(1) Reagents--(i) Water. All water used in these procedures shall be
demineralized (deionized), freshly distilled water.
(ii) n-Heptane. Reagent grade, freshly distilled n-heptane shall be
used.
(2) Determination of total amount of extractives. All determinations
shall be done in duplicate using duplicate blanks. Approximately 400
grams of sample (accurately weighed) shall be placed in a 2-liter
Erlenmeyer flask. Add 1,200 milliliters of solvent and cover the flask
with aluminum foil. The covered flask and contents are suspended in a
thermostated bath and are kept, with continual shaking at 150 [deg]F for
2 hours. The solution is then filtered through a No. 42 Whatman filter
paper, and the filtrate is collected in a graduated cylinder. The total
amount of filtrate (without washing) is measured and called A
milliliters. The filtrate is transferred to a Pyrex (or equivalent)
beaker and evaporated on a steam bath under a stream of nitrogen
[[Page 325]]
to a small volume (approximately 50-60 milliliters). The concentrated
filtrate is then quantitatively transferred to a tared 100-milliliter
Pyrex beaker using small, fresh portions of solvent and a rubber
policeman to effect the transfer. The concentrated filtrate is
evaporated almost to dryness on a hotplate under nitrogen, and is then
transferred to a drying oven at 230 [deg]F in the case of the aqueous
extract or to a vacuum oven at 150 [deg]F in the case of the heptane
extract. In the case of the aqueous extract, the evaporation to constant
weight is completed in 15 minutes at 230 [deg]F; and in the case of
heptane extract, it is overnight under vacuum at 150 [deg]F. The residue
is weighed and corrected for the solvent blank. Calculation:
[GRAPHIC] [TIFF OMITTED] TR01JA93.401
(3) Vinyl chloride-ethylene copolymer content of aqueous extract--
(i) Principle. The vinyl chloride-ethylene copolymer content of the
aqueous extract can be determined by determining the organic chlorine
content and calculating the amount of copolymer equivalent to the
organic chlorine content.
(ii) Total organic chlorine content. A weighed sample of
approximately 400 grams is extracted with 1,200 milliliters of water at
150 [deg]F for 2 hours, filtered, and the volume of filtrate is measured
(A milliliters) as described in paragraph (d)(2) of this section.
(a) A slurry of Amberlite IRA-400, or equivalent, is made with
distilled water in a 150-milliliter beaker. The slurry is added to a
chromatographic column until it is filled to about half its length. This
should give a volume of resin of 15-25 milliliters. The liquid must not
be allowed to drain below the top of the packed column.
(b) The column is regenerated to the basic (OH) form by slowly
passing through it (10.15 milliliters per minute) 10 grams of sodium
hydroxide dissolved in 200 milliliters of water. The column is washed
with distilled water until the effluent is neutral to phenolphthalein.
One drop of methyl red indicator is added to the A milliliters of
filtered aqueous extract and, if on the basic side (yellow), nitric acid
is added drop by drop until the solution turns pink.
(c) The extract is deionized by passing it through the exchange
column at a rate of 10.15 milliliters per minute. The column is washed
with 200 milliliters of distilled water. The deionized extract and
washings are collected in a 1,500-milliliter beaker. The solution is
evaporated carefully on a steam plate to a volume of approximately 50
milliliters and then transferred quantitatively, a little at a time, to
a clean 22-milliliter Parr cup, also on the steam plate. The solution is
evaporated to dryness. Next 0.25 gram of sucrose and 0.5 gram of benzoic
acid are added to the cup. One scoop (approximately 15 grams) of sodium
peroxide is then added to the cup. The bomb is assembled and ignition is
conducted in the usual fashion.
(d) After the bomb has cooled, it is rinsed thoroughly with
distilled water and disassembled. The top of the bomb is rinsed into a
250-milliliter beaker with distilled water. The beaker is placed on the
steam plate. The bomb cup is placed in the beaker and carefully tipped
over to allow the water to leach out the combustion mixture. After the
bubbling has stopped, the cup is removed from the beaker and rinsed
thoroughly. The solution is cooled to room temperature and cautiously
neutralized with concentrated nitric acid by slowly pouring the acid
down a stirring rod until the bubbling ceases. The solution is cooled
and an equal volume of acetone is added.
(e) The solution is titrated with 0.005 N silver nitrate using
standard potentiometric titration techniques with a silver electrode as
indicator and a potassium nitrate modified calomel electrode as a
reference electrode. An expanded scale recording titrimeter.
[[Page 326]]
Metrohm Potentiograph 2336 or equivalent, should be used; a complete
blank must be run in duplicate.
(iii) Calculations.
[GRAPHIC] [TIFF OMITTED] TR01JA93.402
where:
T=Milliliters of silver nitrate (sample minus blank)xnormality of silver
nitrate.
F=1,200/A (as defined above)
(e) The vinyl chloride-ethylene copolymers identified in and
complying with this section, when used as components of the food-contact
surface of any article that is the subject of a regulation in parts 174,
175, 176, 177, 178 and Sec. 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.
(f) The provisions of this section are not applicable to vinyl
chloride-ethylene copolymers used as provided in Sec. Sec. 175.105 and
176.180 of this chapter.
[42 FR 14572, Mar. 15, 1977, as amended at 49 FR 10110, Mar. 19, 1984]
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