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§177.1820 Styrene-maleic anhydride copolymers.
Styrene-maleic anhydride copolymers identified in paragraph （a） of this section may be safely used as articles or components of articles intended for use in contact with food, subject to provisions of this section.
（a） For the purpose of this section, styrene-maleic anhydride copolymers are those produced by the polymerization of styrene and maleic anhydride so that the finished polymers meet the specifications prescribed in paragraph （b） of this section, when tested by the methods described in paragraph （c） of this section.
（b） Specifications:
| Styrene-maleic copolymers | Molecular weight (minimum number average) | Residual styrene monomer | Residual maleic anhydride monomer | Maximum extractable fraction in distilled water at specified temperatures, times, and particle size | Maximum extractable fraction in n-heptane at specified temperatures, times, and particle size |
| 1. Styrene-maleic anhydride copolymers containing not more than 15 pct maleic anhydride units by weight; for use as articles or as components of articles that contact food of Types I, II, III, IV-A, IV-B, V, VI-B (except carbonated beverages), VII-A, VII-B, VIII, and IX identified in table 1 in § 176.170(c) of this chapter under conditions of use B, C, D, E, F, G, and H described in table 2 in § 176.170(c) of this chapter | 70,000 | 0.3 weight percent | 0.1 weight percent | 0.006 weight percent at reflux temperature for 1 hr utilizing particles of a size that will pass through a U.S. standard sieve No. 10 and will be held on a U.S. standard sieve No. 20 | 0.02 weight percent at 73 °F for 2 hr utilizing particles of a size that will pass through a U.S. standard sieve No. 10 and will be held on a U.S. standard sieve No. 20 |
| 2. Styrene-maleic anhydride copolymer modified with butadiene, (CAS Reg. No. 27288-99-9) containing not more than 15 percent maleic anhydride units by weight and not more than 20 percent styrene-butadiene and/or butadiene rubber units by weight; for use (except carbonated beverage bottles) as articles or as components of articles that contact food of Types I, II, III, IV-A, IV-B, V, VI, VII-A, VII-B, VIII, and IX identified in table I in § 176.170(c) of this chapter under conditions of use B, C, D, E, F, G, and H described in table 2 in § 176.170(c) of this chapter | 0.3 | 0.1 | 0.015 weight percent at reflux temperature for 1 hour utilizing particles of a size that will pass through a U.S. standard sieve No. 10 and will be held on a U.S. standard sieve No. 20 | 1.0 weight percent at 23 °C (73 °F) for 2 hours utilizing particles of a size that will pass through a U.S. standard sieve No. 10 and will be held on a U.S. standard sieve No. 20. |
（c） The analytical methods for determining conformance with specifications for styrene-maleic anhydride copolymers prescribed in this section are as follows:
（1） Molecular weight. Molecular weight shall be determined by membrane osmometry.
（2） Residual styrene monomer content. Residual styrene monomer content shall be determined by the method described in § 177.1640（d）.
（3） Residual maleic anhydride monomer content. Residual maleic anhydride monomer content shall be determined by a gas chromatographic method titled “Determination of Residual Maleic Anhydride in Polymers by Gas Chromatography,” 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.
（d） The provisions of this section are not applicable to styrene-maleic anhydride copolymers listed in other sections of this subpart.
[42 FR 14572, Mar. 15, 1977, as amended at 47 FR 11844, Mar. 19, 1982; 47 FR 14698, Apr. 6, 1982; 54 FR 24898, June 12, 1989]
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