[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: 21CFR177.1500]
[Page 277-284]
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. 177.1500 Nylon resins.
The nylon resins listed in paragraph (a) of this section may be
safely used to produce articles intended for use in processing,
handling, and packaging food, subject to the provisions of this section:
(a) The nylon resins are manufactured as described in this paragraph
so as to meet the specifications prescribed in paragraph (b) of this
section when tested by the methods described in paragraph (d) of this
section.
(1) Nylon 66 resins are manufactured by the condensation of
hexamethylene-diamine and adipic acid.
(2) Nylon 610 resins are manufactured by the condensation of
hexamethylene-diamine and sebacic acid.
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(3) Nylon 66/610 resins are manufactured by the condensation of
equal-weight mixtures of nylon 66 salts and nylon 610 salts.
(4) Nylon 6/66 resins manufactured by the condensation and
polymerization of Nylon 66 salts and epsilon-caprolactam.
(5) Nylon 11 resins are manufactured by the condensation of 11-
aminoundecanoic acid.
(6) Nylon 6 resins are manufactured by the polymerization of
epsilon-caprolactam.
(7) Nylon 66T resins are manufactured by the condensation of
hexamethyl-enediamine, adipic acid, and terephthalic acid such that
composition in terms of ingredients is 43.10.2
weight percent hexamethyl-enediamine, 35.31.2
weight percent adipic acid, and 21.61.2 weight
percent terephthalic acid.
(8) Nylon 612 resins are manufactured by the condensation of
hexamethylenediamine and dodecanedioic acid.
(9) Nylon 12 resins are manufactured by the condensation of omega-
laurolactam.
(10)(i) Impact modified Nylon MXD-6 resins (CAS Reg. No. 59655-05-9)
manufactured by the condensation of adipic acid, 1,3-
benzenedimethanamine, and alpha-(3-aminopropyl)-omega-(3-amino-
propoxy)poly- oxyethylene under such conditions that the alpha-(3-amino-
propyl)-omega-(3-aminopropoxy) polyoxyethylene monomer content does not
exceed 7 percent by weight of the finished resin.
(ii) Nylon MXD-6 resins (CAS Reg. No. 25718-70-1) manufactured by
the condensation of adipic acid and 1,3-benzenedimethanamine.
(11) Nylon 12T resins are manufactured by the condensation of omega-
laurolactam (CAS Reg. No. 0947-04-6), isophthalic acid (CAS Reg. No.
0121-91-5), and bis(4-amino-3-methylcycl-ohexyl)methane (CAS Reg. No.
6864-37-5) such that the composition in terms of ingredients is
34.41.5 weight percent omega-laurolactam,
26.80.4 weight percent isophthalic acid, and
38.80.5 weight percent bis(4-amino-3-
methylcyclohexyl)-methane.
(12) Nylon 6I/6T resins (CAS Reg. No. 25750-23-6) are manufactured
by the condensation of hexamethylenediamine, terephthalic acid, and
isophthalic acid such that 65 to 80 percent of the polymer units are
derived from hexamethylene isophthalamide.
(13)(i) Nylon 6/12 resins (CAS Reg. No. 25191-04-2) are manufactured
by the copolymerization of a 1 to 1 ratio by weight of epsilon-
caprolactam and omega-laurolactam.
(ii) Nylon 6/12 resins (CAS Reg. No. 25191-04-2) are manufactured by
the copolymerization of a ratio of at least 80 weight percent of
epsilon-caprolactam and no more than 20 weight percent of omega-
laurolactam.
(14) Nylon 6/69 resins (CAS Reg. No. 51995-62-1) are manufactured by
the condensation of 49.5+0.5 weight percent epsilon-caprolactam,
19.4+0.2 weight percent hexamethylenediamine and 31.2+0.3 weight percent
azelaic acid.
(15) Nylon 46 resins (CAS Reg. No. 50327-77-0) are manufactured by
the condensation of 1,4-butanediamine and adipic acid.
(16) Nylon resins PA 6-3-T (CAS Registry No. 26246-77-5) are
manufactured by the condensation of 50 mol percent 1,4-
benzenedicarboxylic acid, dimethyl ester and 50 mol percent of an
equimolar mixture of 2,2,4-trimethyl-1,6-hexanediamine and 2,4,4-
trimethyl-1,6-hexanediamine.
(b) Specifications:
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Maximum extractable fraction in
selected solvents (expressed in
Melting percent by weight of resin)
Specific point Solubility in boiling ----------------------------------
Nylon resins gravity (degrees 4.2N HC1 Viscosity No. (mL/g) 95
Fahrenheit) percent Ethyl
Water ethyl acetate Benzene
alcohol
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1. Nylon 66 resins.................... 1.14140 using the 3.0
specified in 21 CFR 177.1395 of this minus 110.......... 0.007 0.64 0.003 0
use (excluding bottles) in contact minus2 [deg]C.
(2) Melting point. The melting point shall be determined as follows:
Use a hot-stage apparatus. The use of crossed nicol prisms with a
microscope hot stage and reading of the thermometer when the
birefringence disappears increases the accuracy. If the crossed nicol
apparatus is not available, use the lowest temperature at which the
sample becomes transparent or the sharp edges or corners of the sample
become rounded as the melting point. In case of doubt as to the onset of
melting, the sample is prodded with a sharp instrument. If it sticks to
the heating block, it is considered to have melted. If the melting point
is low, dry the sample in an oven at 85 [deg]C for 24 hours in a
nitrogen atmosphere then repeat the test.
(3) Solubility in boiling 4.2N HCl. The test shall be run on a
sample approximately the size of a \1/8\-inch cube in at least 25
milliliters of 4.2 normal hydrochloric acid.
(4) Maximum extractable fraction in selected solvents. The procedure
for determining the maximum extractable fraction of the nylon resins in
selected solvents is as follows:
(i) Film should be cut with ordinary scissors into pieces of a
convenient size such as \1/4\-inch squares, for the extraction tests
described in this section. The granules of nylon molding powders are in
the proper form for the extraction tests. Samples of fabricated articles
such as pipe, fittings, and other similar articles must be cut to
approximately the size of the molding powder. This can be done
conveniently by using a small-scale commercial plastics granulator and
cutting the sample through a screen having \1/4\-inch mesh. Fine
particles should be separated from the cut resin by screening through a
20-mesh screen. The material retained on the screen is suitable for the
extraction tests.
(ii) The organic solvents must be of American Chemical Society
analytical reagent grade; distilled water is used. Approximately 30
grams of the prepared sample is weighed to the nearest milligram. The
weighed resin is transferred to a 500-milliliter round-bottom flask
equipped with a reflux condenser. Approximately 300-milliliters of
solvent is added to the flask and the contents refluxed gently for 8
hours with a heating mantle. The solvent is then filtered off
immediately while still hot, using a Buchner funnel approximately 5
inches in diameter, a suction flask, and a hardened filter paper
(Whatman No. 50 or equivalent). The paper is wet with the solvent and a
slight suction applied just before starting the filtration. The resin is
washed twice with approximately 100-milliliter portions of solvent and
the combined filtrate and washings are reduced to approximately 25
milliliters by evaporation at reduced pressure (50 millimeters to 100
millimeters of mercury, absolute), heating as necessary. The contents of
the flask are transferred to an evaporation dish
[[Page 284]]
(which has been held in a vacuum desiccator over anhydrous calcium
sulfate until constant weight has been attained) and carefully
evaporated to dryness. The weight of the solid residue is determined by
difference after holding in a vacuum desiccator over anhydrous calcium
sulfate until constant weight has been attained. The percent of solids
extracted is calculated by dividing the weight of the solid residue by
the weight of the sample and multiplying by 100.
(5) Viscosity number (VN). (i) The viscosity number (VN) for Nylon
6/12 resin in a 96 percent sulfuric acid solution (5 milligrams resin
per milliliter) shall be determined at 25 [deg]C (77 [deg]F) by method
ISO 307-1984(E), ``Plastics-Polyamides-Determination of Viscosity
Number,'' which is incorporated by reference. Copies are available from
the Center for Food Safety and Applied Nutrition (HFS-200), Food and
Drug Administration, 5100 Paint Branch Pkwy., College Park, MD 20740, or
available for inspection 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.
(ii) The viscosity number (VN) for Nylon 6/69 and Nylon PA-6-3-T
resins in a 99 percent cresol solution (5 milligrams resin per
milliliter) shall be determined at 25 [deg]C (77 [deg]F) by method ISO
307-1984(E), ``Plastics-Polyamides-Determination of Viscosity Number,''
which is incorporated by reference. The availability of this
incorporation by reference is given in paragraph (d)(5)(i) of this
section.
[42 FR 14572, Mar. 15, 1977]
Editorial Note: For Federal Register citations affecting Sec.
177.1500, see the List of CFR Sections Affected, which appears in the
Finding Aids section of the printed volume and on GPO Access.