                                   TBS/AFDC 2(625) CD1 
                                           ICS 67:250  
  
 
©TBS_202 1 DRAFT TANZANIA STANDARD  
 
 
 
 
 
 
 Specification for plastic materials for food contact applications part 
6: Polyalkylene  Terephthalate (PET  and PBT )   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS  
                                      TBS/AFDC 2(625) CD1 
                                           ICS 67:250  
  
 
©TBS_202 1 0. Foreword  
Polyalkylene terephthalates ( saturated p olyes ters) are amongst the thermoplastic materials used 
extensively for packaging of foodstuffs . Polyethylene terephthalate ( PET) Polyet hylene terephthalate is 
the most common polyester used in food packaging applications. PET is a good gas and water vapou r 
barrier, is strong, offers good clarity and is temperature resistant. Crystalline PET (CPET) has poorer 
optical properties  but improve d heat resistance melting at temperatures in excess of 270°C. Flexible PET 
film is used for barrier pouches and top webs  as a lidding material for tray packs. CPET is used for dual 
ovenable pre -formed base trays where its high temperature resis tance makes it an ideal container for 
microwave and convection oven cooking of food.  
The number of significant places retained in t he rounded off value should be the same as that of the 
specified value in this standard.  
In the preparation of this stan dard assistance has been derived from: IS 12252:1987 Specification for, 
polyalkylene  terephthalates (PET and PBT) for their safe use in contact with foodstuffs pharmaceuticals 
and drinking water  published by Bureau of Indian Standards (BIS )  
In reporting t he results of a test or analysis made in accordance with this Tanzania Standard, if the final 
value observed or calculated is to be roun ded off, it shall be done in accordance with TZS 4.  
1.0 Scope  
This standard specifies the requirements. and methods of sampling and test  for polyalkylene 
terephthalates (PET and PBT) also known as thermoplastic saturated polyesters polymer materials for th e 
manufacture of plastic items used in contact with foodstuffs  
This standard does not purport to establis h the s uitability of the packag ing media with particular foodstuffs  
from other than toxicological considerations   
2.    Normative Refe rences   
The foll owing referenced standards referred to in the text in such a way that some or all of their content 
constitutes r equirements of this stan dard.  For dated references, only the edition cited applies. For 
undated references, the latest edition of the reference d document (including any amendments) applies.  
TZS 4: Rounding off numerical value s  
 AFDC 2( 229) CD1: Determination of overall migrati on of constituents of plastics materials   
             and articles intended to come in contact with foodstuffs - Metho d of analysis  
FTZS 2927 -2:2021 Specification for plastic materials for food contac t applications part 2: Polyethylene  
   (PE)   
AFDC 2 (231) CD1: Specification for plastic materials for food contact applications part 3: colorants  
 3.   Term s and definiti ons 
3.1 Polyethylene Terephthalate (PET)                                     TBS/AFDC 2(625) CD1 
                                           ICS 67:250  
  
 
©TBS_202 1  the basic material produced by the c atalytic condensation at high temperature and reduced pre ssure of 
dimethyl terephthalate (DMT) terephthalic acid (PTA) and if required, relatively small amounts of dimethyl 
isophthalate (DMI) isophthalic acid (IPA) with mono -ethylene glycol.  
3.2 Polybutyle ne Terephthalate (PBT)  
the basic material produced by th e catalytic condensation at high temperature and reduced pressure of 
DMT/PTA (and, if required, relatively small amounts  of DMI/IPA) with 1,4 butanediol  
4.   Requirements  
4.1 Basic Material  
To compl y with this standard, the thermoplastic (saturated) polye ster defined in  3.1 and 3.2  shall be made 
in such a way that they contain no ingredients or residues of ingredients othe r than those laid down in 
clause 4.1.1 to 4.1.5   
4.1.1 Basic Raw Materials  
the following basic raw materials may be used  
i) Mono ethylene glycol (MEG)  
ii) 1, 4 Butanediol  
iii) Dimethyl terephthalate (DMT)  
iv) Dimethyl isophthalate (DMI)  
v) Terephthalic acid (TPA)  
vi) Isophtha lic acid (IPA)  
4.1.1.1 the polymer shall exi st at least 50 percent of units derived from T PA.  
4.1.1.2 to the thermoplastic polyesters m ade from the above raw materials polyethylene up to 5 per - cent 
used conforming to FTZS 2927 -2:2021  may also be added.  
4.1.2 residual  catalyst   
Table 1: maximum limits  for the residual catalysts  
Residual catalyst  Maximum limits (mg/kg or ppm)  Test metho ds  
Antimony  350  
 
AFDC  2 (229) CD1 Gallium  20 
Germanium  100 
Cobalt  125 
Lithium  130 
Manganese  80                                    TBS/AFDC 2(625) CD1 
                                           ICS 67:250  
  
 
©TBS_202 1  
 
 
 
 
4.1.3 Crystallization a ccelerators  
Table 2: maximum limits for the crystallization accelerators   
4.1.4 Auxiliary items for Working  
the follo wing auxiliary items may be present with limits prescribed against each:  
Table 3: maximum limits for the auxiliary items in percentage  
 Auxiliary items  Maximum limits (percent)  Test methods  
Calcium s tearate and zinc stearate together  0.5  
 
 
AFDC2(229 ) CD1 Synthetic paraffin  0.25 
Iso-butyl stearate  0.2 
Even numbered, saturated , aliphatic primary 
alcohols of the chain length C 12 to C 20  0.5 
Low molecular polyolefins  0.5 
 silicon oil  0.3 
Penta -erythrite -ester of saturated even 
numbered ali phatic mono  carbonic acids of 
the chain length C 14 to C 32  1.0 
 4.1.5 Pigments and  Colourants  
In case the coloured material is used for food packaging applications, it shall comply with the list and 
limits of pigments and colourants prescribed in AFDC  2(231) CD1.  
4.2 Overall Migration  
The material shall comply with the overall migratio n limits of 60mg/ L, max of simulant and 10 mg/dm2, 
max of the surface of the material or article when tested by the meth od prescribed in AFDC 2( 229) CD1 
4.3 Storage and Contr ol 
4.3.1 Storage  Zinc  80 
Titanium  120 
Crystalliz ation Accelerators  Maximum limits (percent)  Test methods  
Talc, free of asbestos  0.25 AFDC2(229) CD1 
Sodium benzoate  0.25                                    TBS/AFDC 2(625) CD1 
                                           ICS 67:250  
  
 
©TBS_202 1 Plastic materials intended for food contact use shall be stored s eparately from other materials in closed, 
properly identified containers.  
4.3.2 Control  
An authorized person shall super vise and control the issue of plastics material to the  process or 
manufacturing area and shall maintain appropriate written records of t he issue of such materials.  
4.3.3 Adequate standards of hygiene shall be maintained at all times and plant operators an d store men 
shall be trained in proper hygiene practic es.  
5. Packing and Marking  
5.1 Packing  
The material shall be packed in gunny/pape r bags with suitable liner, as agreed between the purchaser 
and the supplier, in a manner so as to ensure that the items  do not become contaminated during storage. 
It shall b e securely sealed to prevent any ingress of moisture.  
5.2 Marking  
Each package s hall be clearly marked with the following information  
a. Manufacturer’s name and/or trade -mark, if any;  
b. Name and type of material;  
c. Month and year of manufacture;  
d. Net mass of  the material; and  
e. Lot and batch number.  
5.2.1 The packages may also be marked  with the Standard Mark.  
6. Sampling  
6.1 Preparation of Test Samples - The method of drawing representative sample of the material and the 
criteria for conformity shall be as p rescribed in annex A.  
 
 
 
 
 
 
 
                                    TBS/AFDC 2(625) CD1 
                                           ICS 67:250  
  
 
©TBS_202 1 Annex A  
Sampling of Polyalkylene Terephthalates (PET and PBT)  
 B-1. General  
B-1.1 In drawing, preparing, storing and handling samples, the following precautions and direc tions shall 
be observed,  
B-1.2 Samples shall not b e taken in an exposed place.  
B-1.3 The sampling instrument, where applicable shall  be made of stainless steel or any other suitable 
material on which the material shall have no action  with plastic s. The in strument shall be clean and dry.  
B-1.4 Precautions  shall be taken to protect the samples, the material being sampled, the sampling 
instrument and the containers for samples from adventitious contamination.  
3.1.5 The samples shall be placed in a suitable, clean, dry, air -tight metal or glass containers on which 
the material has no action. The sample containers shall be of such a size th at they are almost completely 
filled by the sample.  
B-1.6 Each sample container shall be sealed airtight with a stopper aft er filling and marked with full details 
of sampling , such as the date of sampling, the month and year of manufacture of the material etc. 
B-1.7 Samples shall be stored in such a manner that the temperature of the material does not vary unduly 
from the room  temperature.  
B-2. Scale of Sampling  
B-2.1 Lot  
In a single consignment, all the packages of the same class, same type, same form an d belonging to the 
same batch of manufacture shall be grouped together to constitute a lot. If a consignment is known to 
consist of packages belonging to different batches of  manufacture of different forms, the packages 
belonging to the same batch of manuf acture and same form shall be grouped together and each such 
group shall constitute a lot.  
 B-3. Preparation of Test Sample s  
B-3.1 From each of the packages of material sele cted, small portions of material shall be drawn with the 
help of a suitable sampli ng instrument. The total quantity of material collected from each package shall be 
sufficient to test all the requirements given in clause 3.  
B-2.1.1 The packages may consis t of container of polyalkylene terephthalate (PET/PBT) chips and its 
rolls, films or vials.  
B-2.2 For. ascertaining the conformity of the material to the requirements of this specification, sample 
shall b e tested from each lot separately. The number of pa ckages to be sampled shall’ depend on the 
size of ‘the lot and shall be in accorda nce with col. 1 and 2 of Table 1.  
B-3.2 In the case of packages consisting of containers, vials, rolls, or films, the numb er of items to be 
selected from a package, for test ing each of the requirements given in clause 3, shall be one.                                     TBS/AFDC 2(625) CD1 
                                           ICS 67:250  
  
 
©TBS_202 1 B-4. Number of Test s  
B-4.1 Test for determining all the requirements given in 3 shall be carried out on the individual test 
samples.  
Table 1  Scale of Sampling  
  
Number of packages in the lot  Sample size  
Up to 50  3 
51 to 150  4 
151 to 300  5 
301 to 300  7 
501 and above   10 
B-5. Criteria for conformity  
B-5.1 From the individual test results, the average Ⴟ and the range (R) shall be calcul ated as follows:   
Ⴟ =        Sum of the test results  
                 Number of tests  
Where:  
R = difference between the maximum and the minimum values of the test results.  
The lot shall be declared as conforming to the requirement of various characteristics if: x + KR ≤ the 
maximum value specified; and where the value of K shall be chosen from’ as given below:   
 
 AQL  
Sample size  0.65 1.00 1.50 2.50 4.00 
3 - - - 0.587  0.502  
4 - 0.651  0.598  0.525  0.450  
5 0.663  0.614  0.565 0.498  0.431  
7 0.613  0.596  0.525  0.465  0.405  
10 0.755 0.703  0.650  0.579  0.507  
 
 
 