GrokFood Home
Loading

177.1810 Styrene block polymers.

Home > Regulations > Indirect food additives: Polymers > 177.1810 Styrene block polymers.



[Code of Federal Regulations]
[Title 21, Volume 3]
[Revised as of April 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 21CFR177.1810]

[Page 318-320]
 
                        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.  177.1810  Styrene block polymers.

    The styrene block polymers identified in paragraph (a) of this 
section may be safely used as articles or as components of articles 
intended for use in contact with food, subject to provisions of this 
section.
    (a) For the purpose of this section, styrene block polymers are 
basic polymers manufactured as described in this paragraph, so that the 
finished polymers meet the specifications prescribed in paragraph (b) of 
this section, when tested by the methods described in paragraph (c) of 
this section.
    (1) Styrene block polymers with 1,3-butadiene are those produced by 
the catalytic solution polymerization of styrene and 1,3-butadiene.
    (2) Styrene block polymers with 2-methyl-1,3-butadiene are those 
produced by the catalytic solution polymerization of styrene and 2-
methyl-1,3-butadiene.
    (3) Styrene block polymers with 1,3-butadiene, hydrogenated are 
those produced by the catalytic solution polymerization of styrene and 
1,3-butadiene, and subsequently hydrogenated.
    (b) Specifications:

----------------------------------------------------------------------------------------------------------------
                                                                                 Maximum            Maximum
                                                                               extractable        extractable
                                                                               fraction in       fraction in 50
                                  Molecular                      Glass       distilled water    percent ethanol
     Styrene block polymers        weight      Solubility      transition      at specified       at specified
                                  (minimum)                      points       temperatures,      temperatures,
                                                                                times, and         times, and
                                                                               thicknesses        thicknesses
----------------------------------------------------------------------------------------------------------------
1. (i) Styrene block polymers        29,000  Completely      -98 [deg]C (-  0.0039 mg/cm\2\    0.002 mg/cm\2\
 with 1,3-butadiene; for use as               soluble in      144 [deg]F)    (0.025 mg/in\2\)   (0.01 mg/in\2\)
 articles or as components of                 toluene.        to -71         of surface at      of surface at 66
 articles that contact food of                                [deg]C (-96    reflux             [deg]C (150
 Types I, II, IV-B, VI, VII-B,                                [deg]F) and    temperature for    [deg]F) for 2 hr
 and VIII identified in table 1                               86 [deg]C      30 min on a 0.19   on a 0.19 cm
 in Sec.   176.170(c) of this                                 (187 [deg]F)   cm (0.075 in)      (0.075 in) thick
 chapter under conditions of                                  to 122         thick sample.      sample.
 use D, E, F, and G described                                 [deg]C (252
 in table 2 in Sec.                                           [deg]F).
 176.170(c) of this chapter.

[[Page 319]]


(ii) Styrene block polymers          29,000  ......do......  ......do.....  ......do.........   Do.
 with 1,3-butadiene; for use as
 components of pressure-
 sensitive adhesives that
 contact food of Types I, II,
 IV-B, VI, VII-B, and VIII
 identified in table 1 in Sec.
  176.170(c) of this chapter
 under conditions of use C, D,
 E, F and G described in table
 2 in Sec.   176.170(c) of this
 chapter, provided the pressure-
 sensitive adhesives be applied
 only to closure tapes for
 sealing containers having a
 capacity of not less than 160
 cc (5.5 fluid ounces) and that
 the area of the adhesive
 exposed to food shall not
 exceed 4.03 cm\2\ (0.625
 in\2\). The pressure-sensitive
 adhesive may contain terpene
 resins as identified in Sec.
 175.125(b)(2) of this chapter.
2. Styrene block polymers with       29,000  ......do......  -65 [deg]C (-  0.002 mg/cm\2\     0.002 mg/cm\2\
 2-methyl-1,3-butadiene; for                                  85 [deg]F)     (0.01 mg/in\2\)    (0.01 mg/in\2\)
 use as articles or as                                        to -47         of surface at      of surface at 66
 components of articles that                                  [deg]C (-53    reflux             [deg]C (150
 contact food of Types I, II,                                 [deg]F) and    temperature for    [deg]F) for 2 hr
 IV-B, VI, VII-B, and VIII                                    86 [deg]C      2 hr on a 0.071    on a 0.071 cm
 identified in table 1 in Sec.                                (187 [deg]F)   cm (0.028 in)      (0.028 in) thick
  176.170(c) of this chapter.                                 to 122         thick sample.      sample.
                                                              [deg]C (252    (Optionally,       (Optionally,
                                                              [deg]F).       maximum net        maximum net
                                                                             residue soluble    residue soluble
                                                                             in chloroform      in chloroform
                                                                             shall not exceed   shall not exceed
                                                                             0.00020 mg/cm\2\   0.00040 mg/cm\2\
                                                                             (0.0013 mg/        (0.0025 mg/
                                                                             in\2\) of          in\2\) of
                                                                             surface.).         surface.)
3. (i) Styrene block polymers        16,000  ......do......  -50 [deg]C (-  0.002 mg/cm\2\     0.002 mg/cm\2\
 with 1,3-butadiene,                                          58 [deg]F)     (0.01 mg/in\2\)    (0.01 mg/in\2\)
 hydrogenated (CAS Reg. No.                                   to -30         of surface at      of surface at 66
 66070-58-4): for use as                                      [deg]C (-22    reflux             [deg]C (150
 articles or as components of                                 [deg]F) and    temperature for    [deg]F) for 2 hr
 articles that contact food of                                92 [deg]C      2 hr on a 0.071    on a 0.071 cm
 Types I, II, IV-B, VI, VII-B,                                (198 [deg]F)   cm (0.028 in)      (0.028 in) thick
 and VIII identified in table 1                               to 98 [deg]C   thick sample.      sample.
 in Sec.   176.170(c) of this                                 (208 [deg]F).
 chapter.
(ii) Styrene block polymers          16,000  ......do......  ......do.....  ......do.........   Do.
 with 1,3-butadiene,
 hydrogenated (CAS Reg. No.
 66070-58-4): for use at levels
 not to exceed 42.4 percent by
 weight as a component of
 closures with sealing gaskets
 that would contact food of
 Types III, IV-A, V, VII-A,
 VIII, and IX identified in
 table 1 in Sec.   176.170(c)
 of this chapter, and in
 condition of use D as
 described under table 2 in
 Sec.   176.170(c) of this
 chapter.
----------------------------------------------------------------------------------------------------------------

    (c) The analytical methods for determining whether styrene block 
polymers conform to the specifications prescribed in this section are as 
follows and are applicable to the finished polymer.
    (1) Molecular weight. Molecular weight shall be determined by 
intrinsic viscosity (or other suitable method).
    (2) Glass transition points. The glass transition points shall be 
determined by either of the following methods:
    (i) ASTM method D2236-70 (``Standard Method of Test for Dynamic 
Mechanical Properties of Plastics by Means of Torsional Pendulum,'' 
which is incorporated by reference; copies are available from American 
Society for Testing and Materials (ASTM), 100

[[Page 320]]

Barr Harbor Dr., West Conshohocken, Philadelphia, PA 19428-2959, 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.) 
modified by using a forced resonant vibration instead of a fixed 
vibration and by using frequencies of 25 to 40 cycles per second instead 
of 0.1 to 10 cycles per second.
    (ii) Direct reading viscoelastometric method titled ``Direct Reading 
Viscoelastrometric Method for Determining Glass Transition Points of 
Styrene Block Polymers'' (which is incorporated by reference; copies are 
available from the Center for Food Safety and Applied Nutrition (HFS-
200), Food and Drug Administration, 5100 Paint Branch Pkwy., College 
Park, MD 20740, 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.), by which the glass transition points are determined in 
the tensile mode of deformation at a frequency of 35 hertz using a 
Rheovibron Model DDV-II (or equivalent) Direct Reading Viscoelastometer. 
Take maxima in the out-of-phase component of the complex modulus as the 
glass transition points. For block polymers of low styrene content or 
for simple block polymers, the polymer may be treated with 0.3 part per 
hundred dicumyl peroxide and cured for 30 minutes at 153 [deg]C to 
accentuate the upper transition point.
    (3) Maximum extractable fractions in distilled water and 50 percent 
ethanol and the maximum net residue solubles in chloroform. The maximum 
extractable fractions in distilled water and 50 percent ethanol, and the 
maximum net residue solubles in chloroform, shall be determined in 
accordance with Sec.  176.170(d)(3) of this chapter using a sandwich 
form of the finished copolymer of the specified thickness and for the 
time and temperature specified in paragraph (b) of this section.
    (d) The provisions of this section are not applicable to butadiene-
styrene copolymers listed in other sections of this subpart.
    (e) The provisions of this section are not applicable to styrene 
block polymers with 1,3-butadiene listed in Sec.  175.105 of this 
chapter.

[42 FR 14572, Mar. 15, 1977, as amended at 42 FR 43621, Aug. 30, 1977; 
47 FR 11844, Mar. 19, 1982; 51 FR 16828, May 7, 1986; 54 FR 24898, June 
12, 1989; 58 FR 65546, Dec. 15, 1993]





Additives that reference this regulation:


Source: U.S. Code of Federal Regulations - CFR Title 21, Part 177, Section 1810


Home | About | Search