The olefin polymers listed 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 the provisions of this section.
(a) For the purpose of this section, olefin polymers are basic polymers manufactured as described in this paragraph, so as to meet the specifications prescribed in paragraph (c) of this section, when tested by the methods described in paragraph (d) of this section.
(1)(i) Polypropylene consists of basic polymers manufactured by the catalytic polymerization of propylene.
(ii) Propylene homopolymer consists of basic polymers manufactured by the catalytic polymerization of propylene with a metallocene catalyst.
(2)(i) Polyethylene consists of basic polymers manufactured by the catalytic polymerization of ethylene.
(ii) Fumaric acid-grafted polyethylene (CAS Reg. No. 26877-81-6) consists of basic polymers manufactured by the catalytic polymerization of ethylene followed by reaction with fumaric acid in the absence of free radical initiators. Such polymers shall contain grafted fumaric acid at levels not to exceed 2 percent by weight of the finished polymer.
(3) Olefin basic copolymers consist of basic copolymers manufactured by the catalytic copolymerization of:
(i) Two or more of the 1-alkenes having 2 to 8 carbon atoms. Such olefin basic copolymers contain not less than 96 weight-percent of polymer units derived from ethylene and/or propylene, except that:
(a)(1) Olefin basic copolymers manufactured by the catalytic copolymerization of ethylene and hexene-1 or ethylene and octene-1 shall contain not less than 90 weight-percent of polymer units derived from ethylene;
(2) Olefin basic copolymers manufactured by the catalytic copolymerization of ethylene and hexene-1 shall contain not less than 80 but not more than 90 weight percent of polymer units derived from ethylene.
(3) Olefin basic copolymers manufactured by the catalytic copolymerization of ethylene and pentene-1 shall contain not less than 90 weight-percent of polymer units derived from ethylene.
(4) Olefin basic copolymers manufactured by the catalytic polymerization of ethylene and octene-1 shall contain not less than 50 weight-percent of polymer units derived from ethylene.
(b) Olefin basic copolymers manufactured by the catalytic copolymerization of ethylene and 4-methylpentene-1 shall contain not less than 89 weight-percent of polymer units derived from ethylene;
(c)(1) Olefin basic copolymers manufactured by the catalytic copolymerization of two or more of the monomers ethylene, propylene, butene-1, 2-methylpropene-1, and 2,4,4-trimethylpentene-1 shall contain not less than 85 weight-percent of polymer units derived from ethylene and/or propylene;
(2) Olefin basic copolymers manufactured by the catalytic copolymerization of propylene and butene-1 shall contain greater than 15 but not greater than 35 weight percent of polymer units derived from butene-1 with the remainder being propylene.
(d) Olefin basic terpolymers manufactured by the catalytic copolymerization of ethylene, hexene-1, and either propylene or butene-1, shall contain not less than 85 weight percent polymer units derived from ethylene.
(e) Olefin basic copolymers manufactured by the catalytic polymerization of ethylene and octene-1, or ethylene, octene-1, and either hexene-1, butene-1, propylene, or 4-methylpentene-1 shall contain not less than 80 weight percent of polymer units derived from ethylene.
(ii) 4-Methylpentene-1 and 1-alkenes having from 6 to 18 carbon atoms. Such olefin basic copolymers shall contain not less than 95 molar percent of polymer units derived from 4-methylpentene-1, except that copolymers manufactured with 1-alkenes having from 12 to 18 carbon atoms shall contain not less than 97 molar percent of polymer units derived from 4-methylpentene-1; or
(iii) Ethylene and propylene that may contain as modifiers not more than 5 weight-percent of total polymer units derived by copolymerization with one or more of the following monomers:
(iv) Ethylene and propylene that may contain as a modifier not more than 4.5 weight percent of total polymer units derived by copolymerization with 1,4-hexadiene.
(v) Ethylene and butene-1 copolymers (CAS Reg. No. 25087-34-7) that shall contain not less than 80 weight percent of polymer units derived from ethylene.
(vi) Olefin basic copolymers (CAS Reg. No. 61615-63-2) manufactured by the catalytic copolymerization of ethylene and propylene with 1,4-hexadiene, followed by reaction with fumaric acid in the absence of free radical initiators. Such polymers shall contain not more than 4.5 percent of polymer units deriving from 1,4-hexadiene by weight of total polymer prior to reaction with fumaric acid and not more than 2.2 percent of grafted fumaric acid by weight of the finished polymer.
(vii) Ethylene and 2-norbornene (CAS Reg. No. 26007-43-2) copolymers that shall contain not less than 30 and not more than 70 mole percent of polymer units derived from 2-norbornene.
(4) Poly(methylpentene) consists of basic polymers manufactured by the catalytic polymerization of 4-methylpentene-1.
(5) Polyethylene graft copolymers consist of polyethylene complying with item 2.2 of paragraph (c) of this section which subsequently has 3a,4,7,7a-tetrahydromethyl-4,7-methanoisobenzofuran-1,3-dione grafted onto it at a level not to exceed 1.7 percent by weight of the finished copolymer.
(6) Ethylene-maleic anhydride copolymers (CAS Reg. No. 9006-26-2) containing no more than 2 percent by weight of copolymer units derived from maleic anhydride.
(b) The basic olefin polymers identified in paragraph (a) of this section may contain optional adjuvant substances required in the production of such basic olefin polymers. The optional adjuvant substances required in the production of the basic olefin polymers or finished food-contact articles may include substances permitted for such use by applicable regulations in parts 170 through 189 of this chapter, substances generally recognized as safe in food and food packaging, substances used in accordance with a prior sanction or approval, and the following:
| Substance | Limitations |
|---|---|
| Aromatic petroleum hydrocarbon resin, hydrogenated (CAS Reg. No. 88526-47-0), produced by the catalytic polymerization of aromatic-substituted olefins from distillates of cracked petroleum stocks with a boiling point no greater than 220 °C (428 °F), and the subsequent catalytic hydrogenation of the resulting aromatic petroleum hydrocarbon resin, having a minimum softening point of 110 °C (230 °F), as determined by ASTM Method E 28-67 (Reapproved 1982), “Standard Test Method for Softening Point by Ring-and-Ball Apparatus,” and a minimum aniline point of 107 °C (225 °F), as determined by ASTM Method D 611-82, “Standard Test Methods for Aniline Point and Mixed Aniline Point of Petroleum Products and Hydrocarbon Solvents,” both of which are incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from the American Society for Testing and Materials, 100 Barr Harbor Dr., West Conshohocken, Philadelphia, PA 19428-2959, or from the Center for Food Safety and Applied Nutrition (HFS-200), Food and Drug Administration, 5001 Campus Dr., College Park, MD 20740, 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: | For use only as an adjuvant at levels not to exceed 25 percent by weight in blends with polypropylene complying with paragraph (c), item 1.1 of this section. The finished polymer may be used in contact with food Types I, II, IV-B, VI-A through VI-C, VII-B, and VIII identified in table 1 of § 176.170(c) of this chapter and under conditions of use B through H described in table 2 of § 176.170(c) of this chapter; and with food Types III, IV-A, V, VII-A, and IX identified in table 1 of § 176.170(c) of this chapter and under conditions of use D through G described in table 2 of § 176.170(c) of this chapter. |
| Colorants used in accordance with § 178.3297 of this chapter | |
| 2,5-Dimethyl-2,5-di( | For use as an initiator in the production of propylene homopolymer complying with § 177.1520(c), item 1.1 and olefin copolymers complying with § 177.1520(c), items 3.1 and 3.2 and containing not less than 75 weight percent of polymer units derived from propylene, provided that the maximum concentration of |
| Methyl methacrylate/butyl acrylate-grafted polypropylene copolymer containing methyl methacrylate/butyl acrylate-grafted polypropylene (CAS Reg. No. 121510-09-6), methyl methacrylate/butyl acrylate copolymer (CAS Reg. No. 25852-37-3), methyl methacrylate homopolymer (CAS Reg. No. 9011-14-7), and polypropylene (CAS Reg. No. 9003-07-0), resulting from the reaction of a mixture of methyl methacrylate and butyl acrylate with polypropylene. The finished product contains no more than 55 percent by weight of polymer units derived from methyl methacrylate and butyl acrylate as determined by a method entitled, “Determination of the Total Acrylic in PP-MMA/BA Polymers,” which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from the Office of Food Additive Safety, Center for Food Safety and Applied Nutrition (HFS-200), Food and Drug Administration, 5001 Campus Dr., College Park, MD 20740, or may be examined at the Food and Drug Administration's Main Library, 10903 New Hampshire Ave., Bldg. 2, Third Floor, Silver Spring, MD 20993, 301-796-2039, or 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: | For use only at levels not to exceed 6 percent by weight of olefin polymers complying with paragraph (c) of this section, items 1.1, 3.1a, 3.2a, and 3.2b, where the copolymers complying with items 3.1a, 3.2a, and 3.2b contain not less than 85 weight-percent of polymer units derived from propylene. |
| Petroleum hydrocarbon resins (cyclopentadiene-type), hydrogenated (CAS Reg. No. 68132-00-3) produced by the thermal polymerization of dicyclopentadiene and cyclodiene codimers (consisting of a mixture of cyclopentadiene, methyl cyclopentadiene, and C | For use only as an adjuvant at levels not to exceed 30 percent by weight in blends with: (1) Polypropylene complying with paragraph (c), item 1.1 of this section, or (2) a copolymer of propylene and ethylene containing not less than 94 weight percent propylene and complying with paragraph (c), item 3.2 of this section. The average thickness of the food-contact film is not to exceed 0.1 millimeter (0.004 inch). The finished polymer may be used in contact with (1) Food types I, II, IV-B, VI-A, VI-B, VII-B, and VIII identified in table 1 of § 176.170(c) of this chapter and under conditions of use C through G described in table 2 of § 176.170(c) of this chapter; and (2) food types III, IV-A, V, VI-C, VII-A, and IX identified in table 1 of § 176.170(c) of this chapter and under conditions of use D through G described in table 2 of § 176.170(c) of this chapter. |
| Polymethylsilsesquioxane (CAS Reg. No. 68554-70-1) | For use only as a surface lubricant or anti-blocking agent in films. |
| Poly(vinylidene fluoride) homopolymer (CAS Reg. No. 24937-79-9), having a melt viscosity of 6 to 37 kilopoise at a shear rate of 100 | For use only as a processing aid in the production of olefin polymers complying with paragraph (c) of this section at levels not to exceed 1.0 percent by weight of the polymer. The finished polymers may be used only under the conditions described in § 176.170(c) of this chapter, table 2, under conditions of use B though H. |
| Polyoxyethylene-grafted polydimethylsiloxane (CAS Reg. No. 68937-54-2) | For use as an extrusion aid in the production of extruded olefin polymers that comply with § 177.1520(c) at levels not to exceed 0.3 percent by weight of the polymer. The finished polymer is used in contact with foods under conditions of use B through H described in table 2 of § 176.170 of this chapter. |
| Triisopropanolamine (CAS Reg. No. 122-20-3) | For use as a Zeigler-Natta-type catalyst deactivator and antioxidant in the production of olefin polymers complying with § 177.1520(c), items 2.1, 2.2, and 2.3, and having a minimum density of 0.94 grams per cubic centimeter, and copolymers complying with § 177.1520(c), items 3.1 and 3.2, for use in contact with all foods under the following conditions of use: (a) films with a maximum thickness of 0.102 millimeter (0.004 inch) may be used under conditions A through H defined in table 2 of § 176.170(c) of this chapter; and (b) articles with thickness greater than 0.102 millimeter (0.004 inch) may be used under conditions C through G defined in table 2 of § 176.170(c) of this chapter. |
| Trimethylpyridine and dimethylpyridine mixture having percent by weight composition as follows: 2,4,6-trimethylpyridine (CAS Reg. No. 108-75-8), not less than 60 percent; 2,3,6-trimethylpyridine (CAS Reg. No. 1462-84-6), not more than 27 percent; 3,5-dimethylpyridine (CAS Reg. No. 591-22-0), not more than 12 percent; and other dimethylpyridines, not more than 6 percent | For use only as an adjuvant substance in the production of propylene homopolymers complying with items 1.1, 1.2, and 1.3, and propylene copolymers complying with items 3.1, and 3.2 of paragraph (c) of this section provided that the adjuvant is used at a level not to exceed 20 parts per million by weight of the olefin polymers. |
| Vinylidene fluoride-hexafluoropropene copolymer (CAS Reg. No. 9011-17-0) having a fluorine content of 65 to 71 percent and a Mooney viscosity of at least 28, as determined by a method entitled “Mooney Viscosity,” which is incorporated by reference in accordance with 5 U.S.C. 552(a). Copies are available from the Center for Food Safety and Applied Nutrition (HFS-200), Food and Drug Administration, 5001 Campus Dr., College Park, MD 20740, 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: | For use only as an extrusion aid in the production of extruded olefin polymers at levels not to exceed 0.2 percent by weight of the polymer. The finished polymers may be used only under the conditions described in § 176.170(c) of this chapter, table 2, under conditions of use B through H. |
| Vinylidene fluoride-hexafluoropropene copolymer (CAS Reg. No. 9011-17-0), having a vinylidene fluoride content of not less than 87 percent but less than 100 percent by weight and a melt viscosity of 12 to 27 kilopoise at a shear rate of 100 | For use only as a processing aid in the production of olefin polymers complying with paragraph (c) of this section at levels not to exceed 1.0 percent by weight of the polymer. The finished polymers may be used only under the conditions described in § 176.170(c) of this chapter, table 2, under conditions of use B though H. |
(c) Specifications:
| Olefin polymers | Density | Melting Point (MP) or softening point (SP) ( | Maximum extractable fraction (expressed as percent by weight of the polymer) in | Maximum soluble fraction (expressed as percent by weight of polymer) in xylene at specified temperatures |
|---|---|---|---|---|
| 1.1a. Polypropylene described in paragraph (a)(1)(i) of this section | 0.880-0.913 | MP: 160°-180 °C | 6.4 pct at reflux temperature | 9.8 pct at 25 °C |
| 1.1b. Propylene homopolymer described in paragraph (a)(1)(ii) of this section | 0.880-0.913- | MP: 150°-180 °C | 6.4 pct at reflux temperature | 9.8 pct at 25 °C |
| 1.2. Polypropylene, noncrystalline; for use only to plasticize polyethylene described under items 2.1 and 2.2 of this table, provided that such plasticized polymers meet the maximum extractable fraction and maximum soluble fraction specifications prescribed for such basic polyethylene | 0.80-0.88 | |||
| 1.3. Polypropylene, noncrystalline, for use only: To plasticize polypropylene described by item 1.1 of this table, provided that such plasticized polymers meet the maximum extractable fraction and maximum soluble fraction specifications prescribed for such basic polypropylene, and further provided that such plasticized polypropylene contacts food only of the types identified in § 176.170(c) of this chapter, table 1, under Types I, II, IV-B, VI-B, VII-B, and VIII; and for use at levels not to exceed 50 pct by weight of any mixture employed as a food-contact coating provided such coatings contact food only of the types identified in § 176.170(c) of this chapter, table 1, under Types I, II, IV-B, VI-B, VII-B, and VIII | 0.80-0.88 | SP:115°-138 °C | ||
| 2.1. Polyethylene for use in articles that contact food except for articles used for packing or holding food during cooking | 0.85-1.00 | 5.5 pct at 50 °C | 11.3 pct at 25 °C | |
| 2.2. Polyethylene for use in articles used for packing or holding food during cooking | 0.85-1.00 | 2.6 pct at 50 °C | Do. | |
| 2.3. Polyethylene for use only as component of food-contact coatings at levels up to and including 50 percent by weight of any mixture employed as a food-contact coating | 0.85-1.00 | 53 pct at 50 °C | 75 pct at 25 °C | |
| 2.4. Olefin polymers described in paragraph (a)(2)(ii) of this section, having a melt flow index not to exceed 17 grams/per 10 minutes as determined by the method described in paragraph (d)(7) of this section, for use in blends with other polymers at levels not to exceed 20 percent by weight of total polymer, subject to the limitation that when contacting food of types III, IV-A, V, VI-C, VII-A, and IX identified in § 176.170(c) of this chapter, Table 1, the polymers shall be used only under conditions of use C, D, E, F, and G, described in § 176.170(c) of this chapter, Table 2. | ||||
| 3.1a. Olefin copolymers described in paragraph (a)(3)(i) of this section for use in articles that contact food except for articles used for packing or holding food during cooking; except olefin copolymers described in paragraph (a)(3)(i)( | 0.85-1.00 | 5.5 pct at 50 °C | 30 pct at 25 °C | |
| 3.1b. Olefin copolymers described in paragraph (a)(3)(i)( | 0.9-1.00 | Do | Do. | |
| 3.1c. Olefin copolymers described in paragraph (a)(3)(i)( | Not less than 0.92 | |||
| 3.2a. Olefin copolymers described in paragraph (a)(3)(i) of this section for use in articles used for packing or holding food during cooking; except olefin copolymers described in paragraph (a)(3)(i)( | 0.85-1.00 | 2.6 pct at 50 °C | Do. | |
| 3.2b. Olefin copolymers described in paragraph (a)(3)(i)( | Do. | |||
| 3.2c. Olefin copolymers described in paragraph (a)(3)(i)( | 0.85-0.92 | |||
| 3.3a. Olefin copolymers described in paragraph (a)(3)(ii) of this section and manufactured with 1-alkenes having from 6 to 10 carbon atoms | ||||
| 3.3b. Olefin copolymers described in paragraph (a)(3)(ii) of this section, provided that such olefin polymers have a melt temperature of 220 °C to 250 °C (428 °F to 482 °F) as determined by the method described in paragraph (d)(8) of this section and minimum intrinsic viscosity of 1.0 as determined in paragraph (d)(9) of this section. | ||||
| 3.4. Olefin copolymers, primarily non-crystalline, described in par. (a)(3) (iii) of this section provided that such olefin polymers have a minimum viscosity average molecular weight of 120,000 as determined by the method described in par. (d)(5) of this section and a minimum Mooney viscosity of 35 as determined by the method described in par. (d)(6) of this section, and further provided that such olefin copolymers contact food only of the types identified in § 176.170(c) of this chapter, table 1, under Types I, II, III, IV-B, VI, VII, VIII, and IX | 0.85-0.90 | |||
| 3.5. Olefin copolymers, primarily non-crystalline, described in paragraph (a)(3)(iv) of this section, provided that such olefin polymers have a minimum viscosity average molecular weight of 95,600 as determined by the method described in paragraph (d)(5) of this section, and further provided that such olefin polymers are used only in blends with olefin polymers described under items 1.1, 2.1, and 2.2 of this table at a maximum level of 25 pct by weight, and provided that such olefin copolymers contact food only of the types identified in § 176.170 (c) of this chapter, table 1, under Types I, II, IV-B, VI, VII-B, and VIII at temperatures not exceeding 190 °F | 0.85-0.90 | |||
| 3.6. Olefin copolymers described in paragraph (a)(3)(v) of this section for use in blends with olefin polymer resins have a melt flow index no greater than 5 grams/10 minutes as determined by the method described in paragraph (d)(7) of this section and the thickness of the finished blends shall not exceed 0.1 millimeter (0.004 inch). The ethylene/butene-1 copolymer may be used subject to the following conditions: (1) For use at a level not to exceed 20 weight percent in polypropylene as described under item 1.1 of this table. (2) For use at a level not to exceed 40 weight percent in polyethylene as described under items 2.1 and 2.2 of this table. (3) For use at a level not to exceed 40 weight percent in olefin copolymers as described under items 3.1 and 3.2 of this table | Not less than 0.88 | |||
| 3.7. Ethylene/propylene copolymers, meeting the identity described in paragraph (a)(3)(i) of this section, containing not less than 80 mole-percent of polymer units derived from ethylene and having a minimum viscosity average molecular weight of 95,000 as determined by the method described in paragraph (d)(5) of this section, and a minimum Mooney viscosity of 13 as determined by the method described in paragraph (d)(6) of this section. Ethylene/propylene copolymers described in this item 3.7 are to be used only in blends with other olefin polymers complying with this section, at levels not to exceed 30 percent by weight of the total polymer blend, and in contact with food only of types identified in § 176.170(c) of this chapter, Table 1, under Types I, II, III, IV-B, VI, VII, VIII, and IX. Additionally, optional adjuvants permitted for use in olefin copolymers complying with item 3.4 of this table may be used in the production of this copolymer | Not less than 0.86 | |||
| 3.8. Olefin polymers described in paragraph (a)(3)(vi) of this section, having a melt flow index not to exceed 9.2 grams per 10 minutes as determined by the method described in paragraph (d)(7) of this section, for use in blends with other polymers at levels not to exceed 8 percent by weight of total polymer, subject to the limitation that when contacting food of types III, IV-A, V, VI-C, VII-A, and IX, identified in § 176.170(c) of this chapter, Table 1, the polymers shall be used only under conditions of use C, D, E, F, and G, described in § 176.170(c) of this chapter, Table 2. | ||||
| 3.9. Olefin copolymers described in paragraph (a)(3)(vii) of this section may only be used in contact with dry foods, Type VIII, as identified in § 176.170(c) of this chapter, Table 1 | Not less than 1.0 | |||
| 4. Poly(methylpentene) | 0.82-0.85 | MP: 235°-250 °C | 6.6 pct at reflux temperature | 7.5 pct at 25 °C |
| 5. Polyethylene copolymer described in paragraph (a)(5) of this section and having a melt index not to exceed 2, for use, either alone or in blends with other olefin polymers, subject to the limitation that when contacting foods of types III, IV-A, V, VI-C, VII-A, VIII, and IX identified in § 176.170(c) of this chapter, table 1, the thickness of the film (in mils) containing the polyethylene graft copolymer times the concentration of the polyethylene graft copolymer shall not exceed a value of 2 | Not less than 0.94 | 0.45 pct at 15 °C | 1.8 pct at 25 °C | |
| 6. Ethylene-maleic anhydride copolymers described in paragraph (a)(6) of this section for use as the adhesive component in multilaminate structures, or as the sealant layer in flexible packaging, in contact with food at temperatures not exceeding 49 °C (120 °F) | 0.92 or greater | 1.36 pct at 50 °C | 2.28 pct at 25 °C |
(d) The analytical methods for determining whether olefin polymers conform to the specifications prescribed in this section are as follows, and are applicable to the basic polymer in film form not exceeding 4 mils in thickness. The film to be tested shall be cut into approximately 1-inch squares by any convenient method that avoids contamination by dust, dirt, or grease (
(1) Density. Density shall be determined by ASTM method D1505-68 (Reapproved 1979), “Standard Test Method for Density of Plastics by the Density-Gradient Technique,” 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) Melting point or softening point - (i) Melting point. The melting point shall be determined by ASTM method D2117-82, “Standard Test Method for Melting Point of Semicrystalline Polymers by the Hot Stage Microscopy Method,” which is incorporated by reference. The availability of this incorporation by reference is given in paragraph (d)(1) of this section.
(ii) Softening point. The softening point shall be determined by ASTM method E28-67 (Reapproved 1982), “Standard Test Method for Softening Point by Ring-and-Ball Apparatus,” which is incorporated by reference. The availability of this incorporation by reference is given in paragraph (d)(1) of this section.
(3) Maximum extractable fraction in n-hexane - (i) Olefin copolymers described in paragraph (a)(3)(ii) of this section, polypropylene, and poly(methylpentene). A sample is refluxed in the solvent for 2 hours and filtered at the boiling point. The filtrate is evaporated and the total residue weighed as a measure of the solvent extractable fraction.
(a) Apparatus. (1) Erlenmeyer flasks, 250-milliliter, with ground joint.
(2) Condensers, Allihn, 400-millimeter jacket, with ground joint.
(3) Funnels, ribbed 75-millimeter diameter, stem cut to 40 millimeters.
(4) Funnels, Buchner type, with coarse-porosity fritted disc, 60-millimeter diameter.
(5) Bell jar for vacuum filtration into beaker.
(b) Reagent. n-Hexane, commercial grade, specific gravity 0.663-0.667 (20 °C/20 °C), boiling range 66 °C-69 °C, or equivalent.
(c) Procedure. Weigh 1 gram of sample accurately and place in a 250-milliliter Erlenmeyer flask containing two or three boiling stones. Add 100 milliliters of solvent, attach the flask to the condenser (use no grease), and reflux the mixture for 2 hours. Remove the flask from the heat, disconnect the condenser, and filter rapidly, while still hot, through a small wad of glass wool packed in a short-stem funnel into a tared 150-millimeter beaker. Rinse the flask and filter with two 10-milliliter portions of the hot solvent, and add the rinsings to the filtrate. Evaporate the filtrate on a stream bath with the aid of a stream of nitrogen. Dry the residue in a vacuum oven at 110 °C for 2 hours, cool in a desiccator, and weigh to the nearest 0.0001 gram. Determine the blank on 120 milliliters of solvent evaporated in a tared 150-milliliter beaker. Correct the sample residue for this blank if significant. Calculation:
(ii) Olefin copolymers described in paragraph (a)(3)(i) of this section and polyethylene. A preweighed sample is extracted at 50 °C for 2 hours and filtered. The filtrate is evaporated and the total residue weighed as a measure of the solvent extractable fraction. Alternatively, the sample is reweighed after the extraction period to give a measure of the solvent extractable fraction. The maximum n-hexane-extractable fraction may be determined by the methods set forth in paragraphs (d)(3)(ii)(a) through (d)(3)(ii)(i) of this section.
(a) Extraction apparatus. Two-liter, straight-walled, Pyrex (or equivalent) resin kettles, fitted with three-hole ground-glass covers are most convenient for this purpose. The cover is fitted with a thermometer, a gas-tight stirrer driven by an air motor or explosion-proof electric motor, and a reflux condenser. The kettle is fitted with an electric heating mantle of appropriate size and shape, which is controlled by a variable-voltage transformer.
(b) Evaporating apparatus. Rapid evaporation of large volumes of solvent requires special precautions to prevent contamination by dust. This is facilitated by a special “gas” cover consisting of an inverted flat Pyrex crystallizing dish of an appropriate size (190 millimeters × 100 millimeters) to fit a 1-liter beaker. Through the center of the dish are sealed an inlet tube for preheated, oxygen-free nitrogen, and an outlet tube located 1 inch off center. Nitrogen is fed from the supply source through a coil of
(c) Reagents - (1) n-Hexane. Spectrograde n-hexane.
(2) Nitrogen. High-purity dry nitrogen containing less than 10 parts per million of oxygen.
(d) Procedure. Transfer 2.5 grams (accurately weighed to nearest 0.001 gram) of the polymer to the resin kettle. Add 1 liter of solvent and clamp top in position. Start water flowing through jacket of the reflux condenser and apply air pressure to the stirring motor to produce vigorous agitation. Turn on heating jacket with transformer set at a predetermined voltage to bring the temperature of the contents to 50 °C within 20-25 minutes. As the thermometer reading approaches 45 °C-47 °C, reduce the voltage to the predetermined setting that will just maintain the temperature at 50 °C. Do not overshoot the prescribed temperature. Should this occur discard the test and start afresh. Exactly 2 hours after the solvent temperature has reached 50 °C, disconnect the heater, remove the resin kettle from the heating jacket, and decant the solvent, while still warm, through a coarse filter paper placed on top of a fritted-glass funnel, collecting the filtrate in a tared, glass-stoppered Erlenmeyer flask of 1-liter capacity. Determine the weight of the filtrate recovered to the nearest gram. Recovery should be at least 90 percent of the original solvent. Losses due to evaporation during heating and filtering have been found not to exceed 10 percent. Transfer about half of the solvent filtrate to a 1-liter beaker placed on an opening in the steam bath and immediately cover with the special “gas” cover, the inlet tube of which has been attached with flexible tetrafluoroethylene tubing to a source of high-purity nitrogen in series with a stainless steel heating coil immersed directly in the body of the steam bath. Maintain a positive flow of warm nitrogen gas throughout the evaporation of the solvent, adding the remainder of the filtrate from the Erlenmeyer flask as the evaporation proceeds. When the volume of the solvent has been reduced to about 50 milliliters, transfer the concentrated liquid to a previously tared weighing dish of suitable size. Wash the beaker twice with 20-30 milliliter portions of warm solvent, adding the washings to the weighing dish while continuing to evaporate the remainder of the solvent under the gas cover with its flow of warm nitrogen directed toward the center of the dish. In the event that an insoluble residue that cannot be removed with warm solvent remains in the beaker, it may be necessary to heat with a small amount of a higher boiling solvent such as benzene or toluene, transferring these washings to the weighing dish before final evaporation to dryness. Transfer the weighing dish with its residue to a vacuum desiccator, and allow it to remain overnight (at least 12 hours), after which the net weight of the dry residue is determined to the nearest 0.0001 gram. Correct the result for any solvent blank equivalent to the nonvolatile matter determined to be contained in the amount of solvents used in the test.
(e) Extraction apparatus for alternate method. Two-liter extraction vessel, such as a resin kettle or round bottom flask, fitted with an Allihn condenser (size C), a 45/50 male joint with a Teflon sleeve, and a Teflon coated stir bar. Water bath maintained at 49.5 °C ±0.5 °C containing a submersible magnetic stirrer motor with power supply. Other suitable means of maintaining temperature control, such as electric heating mantles, may be used provided that the temperature range can be strictly maintained.
(f) Sample basket (Optional). A perforated stainless steel cylindrical basket that is approximately 1.5 inches in diameter, 1.6 inches high, and has perforations of 0.125 inches in diameter for 33 holes/in
(g) Vacuum oven. Capable of maintaining 80 °C ±5 °C and a minimum of 635 millimeters of mercury pressure.
(h) Reagents. n-Hexane, reagent or spectrograde, aromatic free (less than 1 milligram per liter), minimum 85 percent n-hexane. This reagent may be reused until it contains a maximum of 1.5 grams polyolefin extractables or has been used for 12 determinations.
(i) Procedure. Assemble the extraction vessel, condenser, and magnetic stir bar. Add n-hexane (1 liter) to the extraction vessel and clamp the assembly into a water bath set at 49.5 °C ±0.5 °C. Start the water flowing through the jacket of the reflux condenser. Adjust the air flow through the stirring motor to give a smooth and uniform stir rate. Allow the n-hexane to preheat for 1 hour to bring the temperature to 49.5 °C±0.5 °C. Temperature is a critical factor in this analysis and it must not vary more than 1 °C. If the temperature exceeds these limits, the test must be discontinued and restarted. Blown, compression molded, or extrusion cast films can be tested. Ideally, the film should be prepared by the same process as will be used with the production resin. Using gloves and metal tweezers to avoid sample contamination, cut about 2.7 grams of the prepared film (4 mils or less in thickness) into about 1-inch squares using clean sharp scissors. Proceed with Option 1 or 2.
Option 1. Using tweezers and noting the number of film pieces, transfer 2.5 grams (accurately weighed to 0.1 milligram) of polymer to the extraction vessel. Extract the film sample for 2 hours. Allow the vessel to cool and filter the contents through a fritted porcelain funnel. Wash the film pieces with fresh n-hexane, aspirate to dryness, and transfer, using tweezers, to a beaker. Recount the film pieces to verify that none were lost during the transfer. Place the beaker in the vacuum oven for 2 hours at 80 °C ±5 °C. After 2 hours, remove and place in a desiccator to cool to room temperature (about 1 hour). After cooling, reweigh the film pieces to the nearest 0.1 milligram. Calculate the percent hexane-extractables content from the weight loss of the original sample. Multiply the result by 0.935 and compare with extraction limits in paragraph (c) of this section. Repeat the above procedure for successive samples.
Option 2. Transfer 2.5±0.05 grams of the prepared 1-inch film sections into a tared sample basket and accurately weigh to the nearest 0.1 milligram. Carefully raise the condenser until the hook on the positioning rod is above the neck of the 2-liter extraction vessel. The basket should be totally below the level of n-hexane solvent. Extract the sample resin film for 2 hours and then raise the basket above the solvent level to drain momentarily. Remove the basket and rinse the contents by immersing several times in fresh n-hexane. Allow the basket to dry between rinsings. Remove the excess solvent by briefly blowing the basket with a stream of nitrogen or dry air. Place the basket in the vacuum oven for 2 hours at 80 °C ±5 °C. After 2 hours, remove and place in a desiccator to cool to room temperature (about 1 hour). After cooling, reweigh the basket to the nearest 0.1 milligram. Calculate the percent hexane extractables content from the weight loss of the original sample. Multiply the result by 0.935 and compare with extraction limits in paragraph (c) of this section. Repeat the above procedure for successive samples. The same solvent charge should remain clear and can be used for at least 12 determinations. Applications of solvent reuse should be confirmed for each resin type before use.
(4) Maximum soluble fraction in xylene - (i) Olefin copolymers described in paragraph (a)(3)(ii) of this section, polypropylene, and poly(methylpen-tene). A sample is dissolved completely in xylene by heating and stirring in a bottle with little free space. The solution is allowed to cool without stirring, whereupon the insoluble portion precipitates and is filtered off; the total solids content of the filtrate is then determined as a measure of the soluble fraction.
(a) Apparatus. (1) Pyrex (or equivalent) reagent bottle, 125-milliliter, glass-stoppered.
(2) Heating mantle of size for 150-milliliter beaker (or suitable aluminum block to fit the 125-milliter bottle described in paragraph (d)(4)(i)(a)(1) of this section.
(3) Magnetic stirrer for use under the heating mantle (combination magnetic stirrer and hotplate may be used if aluminum block is used in place of heating mantle).
(4) Variable-voltage transformer, 7.5 amperes.
(5) Tetrafluoroethylene-resin-coated stirring bar, 1-inch long.
(6) Constant temperature water bath maintained at 25 °C±0.5 °C.
(7) Aluminum dishes, 18 millimeters × 60 millimeters, disposable.
(8) Funnel, Buchner type, with coarse-porosity fritted disc, 30-60 millimeter diameter.
(b) Reagent. Xylene with antioxidant. Dissolve 0.020 gram of phenyl-β- naphthylamine in 1 liter of industrial grade xylene having specific gravity 0.856-0.867 (20 °C/20 °C) and boiling range 123 °C-160 °C.
(c) Procedure. Weigh 1 to 2 grams of sample to the nearest 0.001 gram and place in a 125-milliliter Pyrex reagent bottle containing a 1-inch long tetrafluoroethylene-resin-coated stirring bar. Add 100 milliliters of solvent, set the stopper in lightly, and place the bottle in the heating mantle or aluminum block maintained at a temperature of 120 °C, and stir with a magnetic stirrer until the sample is completely dissolved. Remove the bottle from the heat and allow it to cool 1 hour in the air, without stirring. Then place the bottle in a water bath maintained at 25 °C ±0.5 °C, and allow to stand 1 hour without stirring. Next, remove the bottle from the water bath, shake, and pour part of the contents into the coarse-porosity fritted-glass funnel. Apply suction, and draw 30-40 milliliters of filtrate through, adding more slurry to the funnel, and catching the filtrate in a large test tube. (If the slurry is hard to filter, add 10 grams of diatomaceous earth filter aid to the bottle and shake vigorously just prior to the filtration.) Pipet a suitable aliquot (preferably 20 milliliters) of the filtrate into a tared aluminum disposable dish. Place the dish on a steam bath covered with a fresh sheet of aluminum foil and invert a short-stemmed 4-inch funnel over the dish. Pass nitrogen (heated if desired) down through the funnel at a rate sufficient to just ripple the surface of the solvent. When the liquid has evaporated, place the dish in a vacuum oven at 140 °C and less than 50 millimeters mercury pressure for 2 hours. Cool in a desiccator and weigh. (Note: If the residue value seems high, redry in the vacuum oven for one-half hour to ensure complete removal of all xylene solvent.) Calculation:
(ii) Olefin copolymers described in paragraph (a)(3)(i) of this section and polyethylene. A sample is extracted in xylene at reflux temperature for 2 hours and filtered. The filtrate is evaporated and the total residue weighed as a measure of soluble fraction.
(a) Apparatus - (1) Extraction apparatus. Two-liter, straight-walled Pyrex (or equivalent) resin kettles, fitted with ground-glass covers, are most convenient for this purpose. The cover is equipped with a thermometer and an efficient reflux condenser. The kettle is fitted with an electric heating mantle of appropriate size and shape which is controlled by a variable-voltage transformer.
(2) Constant temperature water bath. It must be large enough to permit immersion of the extraction kettle and set to maintain 25 °C ±0.1 °C.
(3) Evaporating apparatus. Gas cover consisting of a flat Pyrex crystallizing dish (190 millimeters × 100 millimeters) inverted to fit over a 1-liter beaker with 8-millimeter gas inlet tube sealed through center and an outlet tube 1 inch off center. The beaker with gas cover is inserted in an electric heating mantle equipped with a variable-voltage transformer. The outlet tube is attached to an efficient condenser mounted on a receiving flask for solvent recovery and having an outlet for connection to an aspirator pump. The heating mantle (with the beaker) is mounted on a magnetic stirring device. An infrared heat lamp is mounted vertically 3-4 inches above the gas cover to prevent condensation of the solvent inside the cover. Make all connections with flexible tetrafluoroethylene tubing.
(b) Reagents - (1) Xylene. American Chemical Society reagent grade that has been redistilled through a fractionating column to reduce the nonvolatile residue.
(2) Nitrogen. High-purity dry nitrogen containing less than 10
(c) Procedure. Transfer 5 grams ±0.001 gram of sample to the resin kettle, add 1,000 milliliters (840 grams) of xylene, and clamp top in position after inserting a piece of glass rod to prevent bumping during reflux. Start water flowing through the jacket of the reflux condenser and apply full voltage (115 volts) to the heating mantle. When the xylene starts to boil, reduce the voltage to a level just sufficient to maintain reflux. After refluxing for at least 2 hours, disconnect the power source to the mantle, remove the kettle, and allow to cool in air until the temperature of the contents drops to 50 °C, after which the kettle may be rapidly cooled to 25 °C-30 °C by immersing in a cold water bath. Transfer the kettle to a constant temperature bath set to maintain 25 °C ±0.1 °C, and allow to equilibrate for a least 1 hour (may be left overnight if convenient). Break up any precipitated polymers that may have formed, and decant the xylene solution successively through a fast filter paper and then through a fritted-glass filter into a tared 1-liter Erlenmeyer flask, collecting only the first 450 milliliters - 500 milliliters of filtrate (any attempt to collect more of the xylene solution usually results in clogging the filter and risking losses). Reweigh the Erlenmeyer flask and calculate the weight of the filtrate obtained to the nearest 0.1 gram. Transfer the filtrate, quantitatively, from the Erlenmeyer flask to the 1-liter beaker, insert the beaker in its heating mantle, add a glass-coated magnetic stirring bar, and mount the gas cover in place, connecting the inlet tube to the nitrogen source and the outlet to the condenser of the receiving flask. Start a flow of nitrogen (2 to 3 liters per minute) into the gas cover and connect an aspirator to the receiver using a free-flow rate equivalent to 6-7 liters of air per minute. With the infrared lamp on, adjust the voltage to the heating mantle to give a distillation rate of 12-13 milliliters per minute when the magnetic stirrer is revolving just fast enough to promote good boiling. When the volume of solvent in the beaker has been reduced to 30-50 milliliters, transfer the concentrated extractive to a suitable weighing dish that has been previously tared (dry). Rinse the beaker twice with 10-20 milliliter portions of fresh xylene, adding the rinsings to the weighing dish. Evaporate the remainder of the xylene on an electric hotplate set at low heat under the gas cover with a stream of nitrogen directed toward the center of the dish. Avoid any charring of the residue. Transfer the weighing dish to a vacuum desiccator at room temperature and allow to remain under reduced pressure for at least 12 hours (overnight), after which determine the net weight of the residue to the nearest 0.0001 gram. Correct the result for nonvolatile solvent blank obtained by evaporating the equivalent amount of xylene under identical conditions. Calculate the weight of residue originally present in the total weight of solvent (840 grams), using the appropriate factor based on the weight of filtrate evaporated.
(5) Viscosity average molecular weight olefin copolymers described in paragraphs (a)(3) (iii) and (iv) of this section. The viscosity average molecular weight shall be determined from the kinematic viscosity (using ASTM method D445-74, “Test for Kinematic Viscosity of Transparent and Opaque Liquids” (Revised 1974), which is incorporated by reference; copies are available from American Society for Testing and Materials (ASTM), 100 Barr Harbor Dr., West Conshohocken, Philadelphia, PA 19428-2959, 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.) of solutions of the copolymers in solvents and at temperatures as follows:
(i) Olefin polymers described in paragraph (a)(3)(iii) of this section in decahydronaphthalene at 135 °C.
(ii) Olefin polymers described in paragraph (a)(3)(iv) of this section in tetrachloroethylene at 30 °C.
(6) Mooney viscosity - olefin copolymers described in paragraph (a)(3)(iii) of this section. Mooney viscosity is determined by ASTM method D1646-81, “Standard Test Method for Rubber - Viscosity and Vulcanization Characteristics (Mooney Viscometer),” which is incorporated by reference (the availability of this incorporation by reference is given in paragraph (d)(1) of this section), using the large rotor at a temperature of 100 °C, except that a temperature of 127 °C shall be used for those copolymers whose Mooney viscosity cannot be determined at 100 °C. The apparatus containing the sample is warmed for 1 minute, run for 8 minutes, and viscosity measurements are then made.
(7) Melt flow index. The melt flow index of olefin polymers described below shall be determined by ASTM method D-1238-82, “Standard Test Method for Flow Rates of Thermoplastics by Extrusion Plastometer,” which is incorporated by reference in accordance with 5 U.S.C. 552(a). The availability of this incorporation by reference is given in paragraph (d)(1) of this section. The olefin polymers and test conditions and procedures are as follows:
| List of polymers | Conditions/procedures |
|---|---|
| Olefin copolymers described in paragraph (a)(3)(i)( | Condition L, procedure A. |
| Olefin copolymers described in paragraph (a)(3)(v) of this section | Condition E, procedure A. |
| Olefin polymers described in paragraph (a)(2)(ii) of this section | Condition E, procedure A. |
| Olefin polymers described in paragraph (a)(3)(vi) of this section | Condition E, procedure A. |
(8) Melting peak temperature. The melt temperature of the olefin polymers described in paragraph (a)(3)(ii) of this section shall be determined by ASTM method D 3418-82, “Standard Test Method for Transition Temperatures of Polymers by Thermal Analysis,” which is incorporated by reference in accordance with 5 U.S.C. 552(a). The availability of this incorporation by reference is given in paragraph (d)(1) of this section.
(9) Intrinsic viscosity. The intrinsic viscosity of the olefin polymers described in paragraph (a)(3)(ii) of this section shall be determined by ASTM method D 1601-78, “Standard Test Method for Dilute Solution Viscosity of Ethylene Polymers,” which is incorporated by reference in accordance with 5 U.S.C. 552(a). The availability of this incorporation by reference is given in paragraph (d)(1) of this section.
(e) Olefin copolymers described in paragraph (a)(3) (i) of this section and polyethylene, alone or in combination, may be subjected to irradiation bombardment from a source not to exceed 2.3 million volts intensity to cause molecular crosslinking of the polymers to impart desired properties, such as increased strength and increased ability to shrink when exposed to heat.
(f) The olefin polymers 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 § 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.
(g) The provisions of this section are not applicable to olefin polymers identified in § 175.105(c) (5) of this chapter and used in food-packaging adhesives complying with § 175.105 of this chapter.