[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: 21CFR177.1980]
[Page 328-331]
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. 177.1980 Vinyl chloride-propylene copolymers.
The vinyl chloride-propylene copolymers identified in paragraph (a)
of this section may be safely used as components of articles intended
for contact with food, subject to the provisions of this section.
(a) For the purpose of this section, vinyl chloride-propylene
copolymers consist of basic copolymers produced by the copolymezation of
vinyl chloride and propylene 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-propylene 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-propylene 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-propylene 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 cyclo hexanone 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 0.17 milligram of vinyl
chloride-propylene copolymer per 100 grams of sample tested as
determined from the organic chlorine content. For the purpose of this
section, the organic chlorine content is the difference between the
total chlorine and ionic chlorine contents determined as described in
paragraph (d) of this section.
(d) Analytical methods: The analytical methods for determining
whether vinyl chloride-propylene 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.
[[Page 329]]
(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 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] TR01JA93.403
(3) Vinyl chloride-propylene copolymer content of aqueous extract--
(i) Principle. The vinyl chloride-propylene 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. The organic chlorine content is the difference
between the total chlorine content and the ionic chlorine content.
(ii) Total chlorine content. A weighed sample is extracted with
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. Two drops of 50 percent by weight sodium hydroxide solution are
added to prevent loss of chloride from ammonium chloride, if present,
and the solution is evaporated to approximately 15 milliliters. The
concentrated filtrate is quantitatively transferred to a 22-milliliter
Parr bomb fusion cup and gently evaporated to dryness. To the contents
of the cup are added 3.5 grams of granular sodium peroxide, 0.1 gram of
powdered starch, and 0.02 gram potassium nitrate; and the contents are
mixed thoroughly. The bomb is assembled, water is added to the recess at
the top of the bomb and ignition is conducted in the usual fashion using
a Meeker burner. The heating is continued for 1 minute after the water
at the top has evaporated. The bomb is quenched in water, rinsed with
distilled water, and placed in a 400-milliliter beaker. The bomb cover
is rinsed with water, catching the washings in the same 400-milliliter
beaker. The bomb is covered with distilled water and a watch glass and
heated until the melt has dissolved. The bomb is removed, rinsed,
catching the rinsings in the beaker, and the solution is acidified with
concentrated nitric acid using methyl purple as an indicator. The beaker
is covered with a watch glass, and the contents are boiled gently for
10.15 minutes. After cooling to room temperature the solution is made
slightly alkaline with 50 percent by weight sodium hydroxide solution,
then acidified with dilute (1:5) nitric acid. Then 1.5 milliliters of 2
N nitric acid per 100 milliliters of solution is added and the solution
is titrated with 0.005 N silver nitrate to the equivalence potential end
point using an expanded
[[Page 330]]
scale pH meter (Beckman Model 76, or equivalent). A complete blank must
be run in duplicate. Calculation:
[GRAPHIC] [TIFF OMITTED] TR01JA93.404
where:
A=volume of filtrate obtained in extraction.
B=milliliters of silver nitrate solution used in sample
titrationxnormality of silver nitrate solution.
C=milliliters of silver nitrate solution used in blank
titrationxnormality of silver nitrate solution.
(iii) Ionic chlorine content. A weighed sample is extracted with
water at 150 [deg]F for 2 hours, filtered, and the volume of filtrate is
measured (A milliliters) as in paragraph (d)(2) of this section. Two
drops of 50 percent by weight sodium hydroxide solution are added and
the solution is evaporated to approximately 150 milliliters. The
solution is quantitatively transferred to a 250-milliliter beaker,
methyl purple indicator is added, and the solution is neutralized with
0.1 N nitric acid. For each 100 milliliters of solution is added 1.5
milliliters of 2 N nitric acid. The solution is titrated with 0.005 N
silver nitrate to the equivalence potential end point, using the
expanded scale pH meter described in paragraph (d)(3)(ii) of this
section. A complete blank must be run in duplicate. Calculation:
[GRAPHIC] [TIFF OMITTED] TR01JA93.405
where:
A=volume of filtrate obtained in extraction.
D=milliliters of silver nitrate solution used in sample
titrationxnormality of silver nitrate solution.
E=milliliters of silver nitrate solution used in blank
titrationxnormality of silver nitrate solution.
(iv) Organic chlorine content and vinyl chloride-propylene copolymer
content of aqueous extract. The organic chlorine content and the vinyl
chloride propylene copolymer content of the aqueous extract is
calculated as follows:
(a) Organic chlorine content. Milliequivalents of organic chlorine
in aqueous extract of 100 grams of sample equal milliequivalents of
total chlorine in aqueous extract of 100 grams of sample (as calculated
in paragraph (d)(3)(ii) of this section) minus milliequivalents of ionic
chlorine in aqueous extract of 100 grams of sample (as calculated in
paragraph (d)(3)(iii) of this section).
(b) Vinyl chloride-propylene copolymer content. Milligrams of vinyl
chloride-propylene copolymer in aqueous extract of 100 grams of sample
equal milliequivalents of organic chlorine in aqueous extract of 100
grams of sample (as calculated in paragraph (d)(3)(iv) (a) of this
section) multiplied by 84.5.
Note: The conversion factor, 84.5, is derived from the equivalent
weight of chlorine divided by the chlorine content of the heptane
extractable fraction.)
(e) The vinyl chloride-propylene 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.
[[Page 331]]
(f) The provisions of this section are not applicable to vinyl
chloride-propylene copolymers used in food-packaging adhesives complying
with Sec. 175.105 of this chapter.
[42 FR 14572, Mar. 15, 1977, as amended at 49 FR 10111, Mar. 19, 1984]
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