---
kind: "section"
citation: "21 C.F.R. § 177.1556"
title: "21"
number: "177.1556"
heading: "Polyaryletherketone resins."
url: "https://uscodex.org/cfr/21/177.1556"
---

# §177.1556. Polyaryletherketone resins.


The poly(oxy-1,4-phenylenecarbonyl-1,4-phenyleneoxy-1,4-phenylenecarbonyl-1,4-phenylenecarbonyl-1,4-phenylene) resins (CAS Reg. No. 55088-54-5 and CAS Reg. No. 60015-05-6 and commonly referred to as polyaryletherketone resins) identified in [paragraph (a)](#a) of this section may be safely used as articles or components of articles intended for repeated use in contact with food, subject to the provisions of this section.

- (a) **Identity.** Polyaryletherketone resins consist of basic resins produced by reacting 4,4′-diphenoxy benzophenone and terephthaloyl dichloride in such a way that the finished resins have a minimum weight average molecular weight of 20,000 grams per mole, as determined by light scattering measurements in sulfuric acid at room temperature.
- (b) **Optional adjuvant substances.** The basic polyaryletherketone resins identified in [paragraph (a)](#a) of this section may contain optional adjuvant substances required in the production of such basic resins. These adjuvants may include substances used in accordance with [§ 174.5](/cfr/21/174.5.md) of this chapter and the following:
  - (1) **Benzoyl chloride, poly(tetrafluoro ethylene).**
  - (2) [Reserved]
- (c) **Extractive limitations.** The finished food-contact article yields net total extractives in each extracting solvent not to exceed 0.052 milligram per square inch (corresponding to 0.008 milligram per square centimeter) of food-contact surface, when extracted at reflux temperature for 2 hours with the following solvents: Distilled water, 50 percent (by volume) ethyl alcohol in distilled water, 3 percent acetic acid (by weight) in distilled water, and n-heptane.
- (d) In testing the finished food-contact article made of polyaryletherketone resin, use a separate test sample for each required extracting solvent.

## Notes

### Amendments

[61 FR 42381, Aug. 15, 1996]

### Authority

Authority: 21 U.S.C. 321, 342, 348, 379e.

### Source

Source: 42 FR 14572, Mar. 15, 1977, unless otherwise noted.

### Amendments

[61 FR 42381, Aug. 15, 1996]