[Code of Federal Regulations]
[Title 21, Volume 3]
[Revised as of April 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR177.1430]

[Page 268-269]
 
                        TITLE 21--FOOD AND DRUGS
 
CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN 
                          SERVICES (CONTINUED)
 
PART 177_INDIRECT FOOD ADDITIVES: POLYMERS--Table of Contents
 
Subpart B_Substances for Use as Basic Components of Single and Repeated 
                        Use Food Contact Surfaces
 
Sec. 177.1430  Isobutylene-butene copolymers.

    Isobutylene-butene copolymers identified in paragraph (a) of this 
section may be safely used as components of articles intended for use in 
contact with food, subject to the provisions of this section.
    (a) For the purpose of this section, isobutylene-butene copolymers 
consist of basic copolymers produced by the copolymerization of 
isobutylene with mixtures of n-butenes such that the finished basic 
copolymers contain not less than 45 weight percent of polymer units 
derived from isobutylene and meet the specifications prescribed in 
paragraph (b) of this section when tested by the methods described in 
paragraph (c) of this section.
    (b) Specifications:

----------------------------------------------------------------------------------------------------------------
                                                                                                        Maximum
     Isobutylene-butene copolymers      Molecular weight (range)           Viscosity (range)            bromine
                                                                                                         value
----------------------------------------------------------------------------------------------------------------
1. Used as release agents in petroleum  300 to 5,000............  40 to 20,000 seconds Saybolt at 200         40
 wax complying with Sec.  178.3710 of                             [deg]F.
 this chapter.
2. Used as plasticizers in              300 to 5,000............  40 to 20,000 seconds Saybolt at 200         40
 polyethylene or polypropylene                                     [deg]F.
 complying with Sec.  177.1520, and
 in polystyrene complying with Sec.
 177.1640.
3. Used as components of nonfood        300 to 5,000............  40 to 20,000 seconds Saybolt at 200         40
 articles complying with Sec. Sec.                               [deg]F.
 175.300, 176.170, 176.210,
 177.2260(d)(2), 177.2800, and
 178.3570 (provided that addition to
 food does not exceed 10 parts per
 million), or Sec.  176.180 of this
 chapter.
4. Used as production aids in the       150 to 5,000............  Less than 20,000 seconds Saybolt at        90.
 manufacture of expanded (foamed)                                  200 [deg]F.
 polystyrene articles complying with
 Sec.  177.1640 of this chapter.

[[Page 269]]


5. Used in release coatings on          150 to 5,000............  Less than 20,000 seconds Saybolt at         90
 backings or linings for pressure-                                 200 [deg]F.
 sensitive adhesive labels complying
 with Sec.  175.125 of this chapter.
----------------------------------------------------------------------------------------------------------------

    (c) The analytical methods for determining whether isobutylene-
butene copolymers conform to the specifications in paragraph (b) are as 
follows:
    (1) Molecular weight. Molecular weight shall be determined by 
American Society for Testing and Materials (ASTM) method D2503-82, 
``Standard Test Method for Molecular Weight (Relative Molecular Mass) of 
Hydrocarbons by Thermoelectric Measurement of Vapor Pressure,'' which is 
incorporated by reference. Copies may be obtained from the American 
Society for Testing Materials, 1916 Race St., Philadelphia, PA 19103, or 
may be examined at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC 20408.
    (2) Viscosity. Viscosity shall be determined by ASTM method D445-74, 
``Test for Kinematic Viscosity of Transparent and Opaque Liquids,'' 
which is incorporated by reference. The availability of this 
incorporation by reference is given in paragraph (c)(1) of this section.
    (3) Maximum bromine value. Maximum bromine value shall be determined 
by ASTM method D1492-78, ``Standard Test Method for Bromine Index of 
Aromatic Hydrocarbons by Coulometric Titration,'' which is incorporated 
by reference. The availability of this incorporation by reference is 
given in paragraph (c)(1) of this section.
    (d) The provisions of this section are not applicable to 
isobutylene-butene copolymers used as provided under Sec. 175.105 of 
this chapter.

[52 FR 11641, Apr. 10, 1987, as amended at 63 FR 36175, July 2, 1998]