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Milliliters of solution taken for total solids determination,

20 Total volume of solvent used in dissolving the sample.

Specify the solvent used along with the percent soluble result.

(ii) Method II-Ethyl acetate or hexane extractable.

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.

Apparatus. 1. Erlenmeyer flasks, 250milliliter, 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 fritted disc, 60-milliliter, porosity coarse.

5. Bell jar for vacuum filtration into

beaker.

6. Laboratory mill, Wiley, intermediate model.

Reagents. 1. Ethyl acetate, 99 percent 20° C. specific gravity 0.899-0.902. 20° C. 2. n-Hexane, commercial grade, specific 20° C. gravity 0.663-0.667; boiling range 66° 20° C. C.-69° C., or equivalent.

Preparation of sample. Flake-No treat

ment.

Film, 2 to 5 mil-Cut into approximately 2-inch squares and separate into individual pieces.

Heavy film; molding powder or molded articles-Cut or tear into pieces no larger than 16-inch cubes. (Two pairs of pliers may be used.) Mix with pulverized dry ice (one part polypropylene to 15-20 parts of solid CO.) and allow to stand 1 to 2 hours. Meanwhile, place a 10-mesh screen in the Wiley mill and pass pulverized dry ice through the mill until it is thoroughly chilled. Then pass the sample through slowly, adding more dry ice if necessary to prevent heat build-up and fusion. Make a second pass of the ground sample and dry ice through the mill. Place the mixture in a large evaporating dish, allow the dry ice to disappear, and continue air drying (or vacuum drying) at room temperature until condensed moisture has evaporated. This procedure will give particles of which approximately 85 percent by weight will pass

through a 16-mesh screen and 50 percent through a 20-mesh screen.

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 two hours.1

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 2 into a tared 150milliliter 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 steam bath with the aid of a stream of nitrogen. Dry the residue in a vacuum oven at 110° C. for two hours, cool in a desiccator and weigh to 0.0001 gram.

Determine the blank on 100 milliliters of solvent evaporated in a tared 150-milliliter beaker. Correct the sample residue for this

blank if significant. Calculation:

Grams of residue Grams of sample

X 100

percent extractable with

Specify the solvent used along with the percent extractable result.

[25 F.R. 3320, Apr. 16, 1960, as amended at 25 F.R. 4544, May 24, 1960, 26 F.R. 6429, July 18, 1961]

§ 121.2502 66 Nylon resin.

66 Nylon resin (polyhexamethylene adipamide), as defined in paragraph (b) of this section, and subject to the conditions prescribed in this section, may safely be used to produce articles intended for use in processing, handling, and packaging food.

(a) 66 nylon is manufactured by the condensation of hexamethylenediamine and adipic acid under controlled conditions whereby it meets the specifications and tests prescribed in paragraphs (b) and (c) of this section.

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(a) Specific gravity-.. 1.14 0.015 Determined by weighing a 1-gram to 5-gram specimen first in air and then in freshly boiled distilled water at 23° C. +2° C.

(b) Melting point.. 475° F. 495° F. The melting point is 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 increase 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° C. for 24 hours in a nitrogen atmosphere.

Dissolves in 1 hour.

(c) Solubility in boiling 4.2N HCl. The test is run on a sample approximately the size of a %-inch cube in at least 25 milliliters of 4.2N HCl.

(2) Extractability limitations using the method described in paragraph (c) of this section.

66 Nylon:

Water

95% ethyl alcoholEthyl acetate__ Benzene

Percent 1.5

1.5

0.2 0.2

(c) The procedure for determining the material extractable from nylon resins by selected solvents is as follows:

(1) 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.

(2) 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 100milliliter 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 (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.

[25 F.R. 13749, Dec. 28, 1960, as amended at 27 F.R. 4063, Apr. 28, 1962]

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(ii) Other properties for identifying 610 nylon:

(a) Specific gravity---

1.09+0.015

Determined by weighing a 1-gram to 5gram specimen first in air and then in freshly boiled distilled water at 23° C. +2° C. (b) Melting point--------- 405° F.-425° F. The melting point is determined as fol

lows: Use a hot-stage apparatus. The use of crossed nicol prisms with a microscope hot stage and reading of the theromometer when the birefringence disappears increase 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° C. for 24 hours in a nitrogen atmosphere.

(c) Solubility in boiling 4.2N Insoluble HCI.

after 1 hour.

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(c) Procedure for determining the material extractable from nylon resins by selected solvents is described in § 121.2502(c).

[25 F.R. 13749, Dec. 28, 1960, as amended at 27 F.R. 4064, Apr. 28, 1962]

§ 121.2504 66/610 Nylon resin.

Copolymer 66/610 nylon, as defined in paragraph (a) of this section, and further subject to the conditions prescribed in this section, may safely be used to produce articles intended for use in processing, handling, and packaging food.

(a) Copolymer 66/610 nylon is manufactured by polymerizing equal weights of the 66 and 610 monomeric salts under controlled conditions whereby it meets the specifications and tests prescribed in paragraphs (b) and (c) of this section.

(b) Specifications—(1) Qualitative tests-(i) Infrared identification. Co

polymer 66/610 nylon has characteristic infrared spectra useful for identification purposes.

(ii) Other properties for identifying copolymer 66/610 nylon:

(a) Specific gravity--1.10 +0.015 Determined by weighing a 1-gram to 5gram specimen first in air and then in freshly boiled distilled water at 32° C. +2° C.

(b) Melting point--------- 375° F.-395° F. The melting point is determined as fol

lows: Use a hot-stage apparatus. The use of crossed nicol prisms with а microscope hot stage and reading of the thermometer when the birefringence disappears increase 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 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° C. for 24 hours in a nitrogen atmosphere. (c) Solubility in boiling 4.2N HCI.

Dissolves in

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1 hour.

Percent

1.5

2.0

1.0

1.0

(c) Procedure for determining the material extractable from nylon resins by selected solvents is described in § 121.2502(c).

[25 F.R. 13749, Dec. 28, 1960, as amended at 27 F.R. 4064, Apr. 28, 1962]

§ 121.2505 Slimicides.

(a) Slimicides may be safely used in the manufacture of paper and paperboard that contact food, in accordance with the following prescribed conditions:

(1) Slimicides are used as antimicrobial agents to control slime in the manufacture of paper and paperboard.

(2) Subject to any prescribed limitations, slimicides are prepared from one or more of the slime-control substances named in paragraph (c) of this section, to which may be added optional adjuvant substances as provided for under paragraph (d) of this section.

(3) Slimicides are added to the process water used in the production of paper or paperboard, and the quantity added

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(d) Adjuvant substances permitted to be used in the preparation of slimicides include substances generally recognized as safe for use in food, substances generally recognized as safe for use in paper and paperboard, substances permitted to be used in paper and paperboard by other regulations in this chapter, and the following:

[26 FR. 8974, Sept. 23, 1961, as amended at 27 F.R. 46, Jan. 4, 1962, 27 F.R. 6928, July 21, 1962]

§ 121.2506 Industrial starch-modified. Industrial starch-modified may be safely used in the preparation of packaging materials under the following prescribed conditions:

(a) Industrial starch-modified is food starch-modified or starch which in accordance with good manufacturing practice has been structurally altered in part in one of the following ways:

(1) By treatment with ethylene oxide so that the finished modified starch con

tains not more than 3.0 percent of reacted ethylene oxide.

(2) By treatment with not more than 4.0 percent B-diethylaminoethylchloride hydrochloride and 3.0 percent propylene oxide, individually or in combination.

(3) By treatment of food starch-modified (§ 121.1031(a)(1)) with not more than 0.3 percent epichlorohydrin.

(4) By treatment with not more than 1.0 percent sodium hydroxide.

(5) By treatment with not more than 3.0 percent dimethylaminoethylmethacrylate.

(b) It is intended for use as follows: (1) In the preparation of surface sizing or coatings for paper, paperboard, or textiles intended for food packaging.

(2) In the fabrication of other food packaging materials when so authorized by the regulations in this subpart f.

(c) To assure safe use of the additive, the label of the food additive container shall bear, in addition to the other information required by the act:

(1) The name of the additive.

(2) Information describing how the starch is modified.

[27 F.R. 223, Jan. 9, 1962, as amended at 27 F.R. 7493, July 31, 1962, 27 F.R. 11944, Dec. 4, 1962]

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Cellophane may be safely used for packaging food in accordance with the following prescribed conditions:

(a) Cellophane consists of a base sheet made from regenerated cellulose to which have been added certain optional substances of a grade of purity suitable for use in food packaging as constituents of the base sheet or as coatings applied to impart desired technological properties.

(b) Subject to any limitations prescribed in this part, the optional substances used in the base sheet and coating may include:

(1) Substances generally recognized as safe in food.

(2) Substances for which prior approval or sanctions permit their use in cellophane, under conditions specified in such sanctions and substances listed in Subpart E, § 121.2001.

(3) Substances that by any regulation promulgated under section 409 of the act may be safely used as components of cellophane.

(4) Substances named in this section and further identified as required.

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