---
kind: "section"
citation: "21 C.F.R. § 173.65"
title: "21"
number: "173.65"
heading: "Divinylbenzene copolymer."
url: "https://uscodex.org/cfr/21/173.65"
---

# §173.65. Divinylbenzene copolymer.


Divinylbenzene copolymer may be used for the removal of organic substances from aqueous foods under the following prescribed conditions:

- (a) The copolymer is prepared in appropriate physical form and is derived by the polymerization of a grade of divinylbenzene which comprises at least 79 weight-percent divinylbenzene, 15 to 20 weight-percent ethylvinylbenzene, and no more than 4 weight-percent nonpolymerizable impurities.
- (b) In accordance with the manufacturer's directions, the copolymer described in [paragraph (a)](#a) of this section is subjected to pre-use extraction with a water soluble alcohol until the level of divinylbenzene in the extract is less than 50 parts per billion as determined by a method titled, “The Determination of Divinylbenzene in Alcohol Extracts of Amberlite XAD-4,” which is incorporated by reference. Copies of this method are available from the Office of Food Additive Safety (HFS-200), Center for Food Safety and Applied Nutrition, Food and Drug Administration, 5001 Campus Dr., College Park, MD 20740, 240-402-1200, 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. The copolymer is then treated with water according to the manufacturer's recommendation to remove the extraction solvent to guarantee a food-grade purity of the resin at the time of use, in accordance with current good manufacturing practice.
- (c) The temperature of the aqueous food stream contacting the polymer is maintained at 79.4 °C (175 °F) or less.
- (d) The copolymer may be used in contact with food only of Types I, II, and VI-B (excluding carbonated beverages) described in table 1 of [paragraph (c)](/cfr/21/176.170.md?p=c) of § 176.170 of this chapter.

## Notes

### Amendments

[50 FR 61, Jan. 2, 1985, as amended at 88 FR 17722, Mar. 24, 2023]

### Authority

Authority: 21 U.S.C. 321, 342, 348.

### Source

Source: 42 FR 14526, Mar. 15, 1977, unless otherwise noted.

### Amendments

[50 FR 61, Jan. 2, 1985, as amended at 88 FR 17722, Mar. 24, 2023]