Dimethylpolysiloxane (substantially free from hydrolyzable chloride and alkoxy groups, no more than 18 percent loss in weight after heating 4 hours at 200° c.; viscosity 300 centistokes, 600 centistokes at 25° C., specific gravity 0.96 to 0.97 at 25° C., refractive index 1.400 to 1.404 at 25° C.) Linoleamide (linoleic acid amide). Oleamide (oleic acid amide).

Palmitamide (palmitic acid amide).

Polyethylene glycol 400.

Polyethylene glycol 1500.

Polyethylene glycol 4000.

Stearamide (stearic acid amide).

(g) Stabilizers.

Aluminum mono-, di-, and tristearate. Ammonium citrate.

Ammonium potassium hydrogen phos

phate.

Calcium acetate.

Calcium carbonate.

Calcium glycerophospate.

Calcium phosphate.

Calcium hydrogen phosphate.

Calcium oleate.

Calcium ricinoleate.

Calcium stearate.

Disodium hydrogen phosphate.

Magnesium glycerophosphate.

Magnesium stearate.

Magnesium phosphate.

Magnesium hydrogen phosphate.

Mono-, di-, and trisodium citrate.

Mono-, di-, and tripotassium citrate.
Potassium oleate.

Potassium stearate.

Sodium pyrophosphate.
Sodium stearate.

Sodium tetrapyrophosphate.

Tin stearate (not to exceed 50 parts per million tin as a migrant in finished food). Zinc orthophosphate (not to exceed 50 parts per million zinc as a migrant in finished food).

Zinc resinate (not to exceed 50 parts per million zinc as a migrant in finished food).

(h) Substances used in the manufacture of paper and paperboard products used in food packaging.

Aliphatic polyoxyethylene ethers.⚫

1-Alkyl

(C-C1)-amino-3-aminopropane

monoacetate.”

Borax or boric acid for use in adhesives, sizes, and coatings.*

Butadiene-styrene copolymer.

Chromium complex of perfluoro-octane sulfonyl glycine for use on paper and paperboard which is waxed.*

Disodium cyanodithioimidocarbamate with ethylene diamine and potassium N-methyl dithiocarbamate and/or sodium 2-mercaptobenzothiazole (slimicides).*

Ethyl acrylate and methyl methacrylate copolymers of itaconic acid or methacrylic acid for use only on paper and paperboard which is waxed.*

Hexamethylene tetramine as a setting agent for protein, including casein.⚫ 1-(2-Hydroxyethyl)-1-(4-chlorobutyl)-2

alkyl (C.-C,,) imidazolinium chloride.⚫
Itaconic acid (polymerized).

Melamine formaldehyde polymer.
Methyl acrylate (polymerized).

Methyl ethers or mono-, di-, and tripropylene glycol.

Myristo chromic chloride complex.
Nitrocellulose.

Polyethylene glycol 400.
Polyvinyl acetate.

Potassium pentachlorophenate as a slime control agent.*

Potassium trichlorophenate as a slime control agent.

Pyrethrins in combination with piperonyl butoxide in outside plies of multiwall bags." Resins from high and low viscosity polyvinyl alcohol for fatty foods only.

Rubber hydrochloride.

Sodium pentachlorophenate as a slime control agent.

Sodium trichlorophenate as a slime control agent.

Stearato-chromic chloride complex.
Titanium dioxide.*

Urea formaldehyde polymer.

Vinylidine chlorides (polymerized).

(Sec. 701, 52 Stat. 1055, as amended; 21 U.S.C. 371. Interprets or applies secs. 201(s), 409, 72 Stat. 1784 et seq.; 21 U.S.C. 321(s), 348) [25 FR. 866, Feb. 2, 1960, as amended at 25 FR. 1773, Mar. 1, 1960]

Subpart F-Food Additives Resulting From Contact With Containers or Equipment and Food Additives Otherwise Affecting Food

AUTHORITY: §§ 121.2501 to 121.2583 issued under sec. 409 (c) (1), 72 Stat. 1786; 21 US.C. 348 (c) (1)).

$121.2501 Polypropylene.

The food additive polypropylene may be present in food when its presence therein is in accordance with the following prescribed conditions:

(a) It is present as a result of contact with polypropylene used in container or equipment material.

(b) The polypropylene has been manufactured by the catalytic polymerization of propylene and specially prepared as a food-packaging grade to meet the following specifications when tested by

Under the conditions of normal use, these substances would not reasonably be expected to migrate to food, based on available scientific information and data.

the analytical methods described in paragraph (c) of this section:

(1) It is completely soluble in decahydronaphthalene at 160° C., with a maximum soluble fraction of 13.4 percent after cooling to 25°C.

(2) It is completely soluble in xylene at 120°C., with a maximum soluble fraction of 9.8 percent after cooling to 25° C.

(3) It has a maximum extractable fraction of 3.6 percent when extracted with ethyl acetate at reflux temperature.

(4) It has a maximum extractable fraction of 6.4 percent when extracted with n-hexane at reflux temperature.

(5) The limits described in this paragraph for solubility and extractability include all the component substances in the polypropylene that may be dissolved or extracted.

(6) The polypropylene contains no other components that are food additives as so defined unless authorized by specific regulation in this part.

(c) The analytical methods for determining that a polypropylene material conforms to the specifications prescribed in this section are as follows:

(1) Qualitative tests-(i) Infrared identification. Polypropylene can be determined by its characteristic infrared spectrum.

(ii) Melting point. Its melting point is 160° C.-180° C. on 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.)

(iii) Density. Its density is 0.8800.913 at 23° C., determined by weighing a 1.0-1.5-inch square film first in air and then in methyl alcohol.

(2) Quantitative tests-(1) Method I-Decahydronaphthalene or xylene soluble fraction.

A. Solution Preparation:

A sample is dissolved completely in decahydronaphthalene or xylene by heating and stirring in a closed system under nitrogen atmosphere to prevent degradation. The solution is allowed to cool, whereupon the insoluble portion of the sample precipitates, is filtered off, and the total-solids content of the filtrate determined as a measure of the decahydronaphthalene or xylene-soluble fraction.

Apparatus. 1. Polymerization tubes, 7inch vials, with neck tooled for crown cap.

2. Crown bottle caps (standard metal beverage cap, without liner). Perforate with two-inch holes.

3. Rubber liner for crown bottle caps. Extract with benzene in Soxhlet extractor until extract is colorless (several days). 4. Ball bearings, steel, %-inch.

5. Magnet, 4,000-5,000 gauss permanent magnet.

6. Heating block, aluminum, with wells of sufficient size to immerse polymerization tubes to a depth of 3 or 4 inches, and maintained at 120° +5° C. or 160° +5° C.

7. Funnel, Buchner type with coarseporosity fritted disc, 30 millimeters to 60 millimeters diameter.

8. Bottle capper (any household bottle rapper with wooden block to hold the polymerization tubes).

Reagents. 1. Decahydronaphthalene con*aining 20 milligrams of antioxidant per Iter-Dissolve 0.020 gram of phenyl-Bnaphthylamine in 1 liter of technical grade decahydronaphthalene.

2. Xylene containing 20 milligrams of antioxidant per liter-Dissolve 0.020 gram of N-phenyl-6-naphthylamine in 1 liter of in

Film-Cut into approximately 1⁄2-inch squares and separate into individual pieces. Molding powder-No treatment.

Molded articles-Cut or tear into pieces no larger than 16-inch cubes (two pairs of pliers may be used).

Procedure. Weigh a 0.4 gram-0.5 gram sample, to the nearest 0.001 gram, into a 7-inch polymerization tube. Add a %-inch steel ball bearing and, with a pipet, 20 milliliters of decahydronaphthalene or xylene containing antioxidant.

Close the tube with a crown cap with rubber liner, connect to a vacuum line by means of a hypodermic needle, evacuate, and refill with nitrogen at atmospheric pressure. Stir the solution by moving the tube up and down between the poles of the permanent magnet, thus raising and lowering the ball bearing in the solution.

Place the tubes in the wells of the heating block (maintained at 120° C. for xylene and at 160° C. for decahydronaphthalene) removing them at about 10-minute intervals and stirring for about 1 minute by means of the magnet and ball bearing. Alternate heating and stirring until the solution is complete with no gel particles. Observe the solution carefully since the gel particles are almost invisible; hold the tube almost horizontally and rotate but avoid undue contact of the solution with the rubber liner. Then allow the tube to stand in the air for a minimum of 1 hour and a maximum of 2 hours to cool and permit precipitation of the insoluble portion.

Uncap the polymerization tube and pour the contents into a coarse-porosity frittedglass funnel. Apply suction with a water aspirator and draw at least 12 milliliters to 13 milliliters of filtrate through. Some samples filter rather slowly, and sometimes less than 10 milliliters is obtained. If the filtration is slow, it should be discontinued after 5 to 10 minutes, and a portion less than 10 milliliters used for the total solids determination. (Slow filtration may be due to failure to thoroughly clean the funnel from a previous determination.)

Determine the total solids on a 10-milliliter portion or less as described in section B. B. Total solids determination:

A sample is weighed into a tared aluminum weighing dish containing glass wool, the dish placed on the surface of an electric hotplate inside a vacuum desiccator whose side walls are cooled with ice water, and the solvent evaporated under vacuum. The solvent condenses on the walls of the desiccator while the glass wool in the dish reduces bumping. The residue in the dish is finally weighed.

Apparatus. 1. Solvent evaporator-This consists of a special electric hotplate mounted in a Pyrex vacuum desiccator. The latter is placed in a cooling bath and evacuated by a mechanical pump.

The component parts are listed below: a. Desiccator and cover, Pyrex glass, large size, 250-millimeter inside diameter flange, provided with cover with opening for No. 8 rubber stopper. Insert the single arm of a 3-millimeter bore, three-way stopcock through a No. 8 rubber stopper and cut off the tubing just below the bottom of the stopper. Connect an 18/9 spherical joint to one of the two upper arms just above the stopcock barrel. Cut off the third arm about 1 inch above the stopcock barrel. Attach a glass tee to this arm with the vertical outlet ground to a flat surface. Insert two electrical wires through the rubber stopper by means of glass tubing with tungsten seals and connect to the hotplate leads with porcelain wire nuts. Connect the external leads to a 110-volt line controlled with a 7.5-ampere Variac. Insert the sharpened sheath of the thermocouple assembly (iron-constantan, silver-soldered in the tip of a 12-inch piece of 14-gage hypodermic tubing) through the stopper. Bend the lower end to form a foot that will press against the hotplate. Insert the rubber stopper tightly in the opening in the desiccator cover and wire in place.

b. Porcelain desiccator plate, 230-millimeter diameter, without feet.

c. Insulating support, transite. Space the two 6-inch squares of 16-inch thick transite with four small 3-inch blocks of transite.

d. Hotplate, electric-For the heating surface, use an 8-inch circle of 3-inch aluminum plate. Back with a 6 x 7 inch piece of %-inch aluminum plate space by about 1-inch strips of -inch aluminum at

each end. Round off any extending corners to the same diameter as the top plate.

Wind a 6-foot length of 275-watt, 1⁄2-inch heating tape around the bottom 6 x 7-inch plate. Connect the two ends of the tapeleads to the power inlet.

e. Cooling bath-Use a covered sheetmetal pan with two openings in the top, one a circular hole just large enough to admit the desiccator, and the other with hinged cover for inserting the cooling medium. The depth of the bath should be equal to the height of the desiccator to the flange of the bottom section.

1. Vacuum pump.

g. Pirani gage (a McLeod gage is satisfactory).

h. Temperature recorder, 0 to 200° C., 24hour chart-Equip with an on-and-off control across the 110-volt power supply so as to control the temperature of the hotplate at the desired setting.

1. Dry ice trap with wide-mouth Dewar flask.

J. Safety shield for desiccator.

2. Aluminum tray, 51⁄2 x 8 x 1 inch deepCommercial frozen-food trays of this size are satisfactory.

3. Shield, drip or spatter-Unfold the corners of an aluminum tray, puncture hole for thermocouple lead, and place loosely over the sample dishes.

4. Drying dishes, aluminum, 50-millimeter diameter, with covers.

5. Oven, drying, maintained at 110° C. ±2° C.

6. Glass wool, Pyrex.

Procedure. Assemble the apparatus as shown in the diagram.

Take sufficient glass wool to fill the weighing dish about three-fourths full when loosely packed. Roll the glass wool into a loose spiral and place in a clean, dry dish. Pass a flame from a Bunsen burner over the surface of the dish so as to melt off any stray wisps of the glass wool. Wipe off any glass fibers on the outside surface of the

dish. Heat the uncovered dishes in a 110° C. oven for 30 minutes, remove, cover, cool in air, and weigh to the nearest 0.0001 gram. Pipet about 10-milliliter aliquots of the sample solution into the dish, wetting the entire glass wool pad.

Place the uncovered dishes in an aluminum tray, maximum of eight dishes per tray. With the hotplate at room temperature and the power off, place the tray of dishes on its top surface. Place the drip or spatter shield loosely over the tray. Place the desiccator lid and guard in position. Make sure the thermocouple is pressing against the bottom of the tray. Fill the cooling bath with ice plus a small amount of water.

Add crushed dry ice to the cooling trap Dewar flask and turn the vacuum pump on. Apply heat at such a rate that the temperature reaches 130° C.-140° C. in 40 to 60 minutes, usually about 80-volt setting of the Variac. Control the temperature at 140° C. for another hour. The pressure should be 800 microns to 1,000 microns at the start, and near the end of the test should drop to 300 microns to 500 microns.

Finally close off the lead to the vacuum pump, turn off the hotplate, and fill the desiccator slowly with nitrogen (about 5 pounds per square inch) admitted through a capillary. Attach the nitrogen feedline from the capillary to the horizontal arm of the glass tee. While holding a soft-rubber stopper on the flat surface of the vertical arm, slowly open the stopcock to the desiccator. Release the stopper; the vacuum will hold it in place until atmospheric pressure is reached, when it will pop off. This prevents blowing the lid off by pressure buildup. Open the desiccator, remove the shield, and then lift out the tray with the drying dishes.

Cover the dishes, allow to cool in air, and weigh.

If the apparatus is to be used again, cool the hotplate by placing a pan of ice on its top surface.