GB/T 17931-2018Poly(ethylene terephthalate) (PET) resin for bottles (English PDF)

1 Scope

GB/T 17931-2018 is the Chinese national standard on poly(ethylene terephthalate) (pet) resin for bottles, in the field of rubber and plastic industries. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 28 December 2018 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 1 November 2019. Classification: ICS 83.080.20, CCS G32. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This Standard specifies the terms and definitions, product classification, requirements, test methods, inspection rules, marking and accompanying documents, packaging, transportation and storage for poly (ethylene terephthalate) (PET) resin for bottles. This Standard applies to homopolymer PET resin that uses purified terephthalic acid and ethylene glycol as the main raw materials, and is produced by direct esterification continuous polycondensation or intermittent polycondensation AND copolymer PET resin that uses purified terephthalic acid, ethylene glycol and isophthalic acid as the main raw materials and adopts direct esterification continuous polycondensation or intermittent polycondensation to produce.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 1033.1-2008, Plastics -- Methods for determining the density of non-cellular plastics -- Part

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

3.1 color b value The degree to which a substance varies from blue to yellow in the CIE standard.

3.2 color L value The brightness of a substance according to the CIE standard.

3.3 impurity Substances other than PET resin.

3.4 powder Debris passing through a test sieve with a mesh size of 800 µm (20 mesh).

3.5 color granule Yellow particles or other colored particles can be seen with the naked eye.

3.6 efficiently endothermic PET resin A PET resin which is polymerized from purified terephthalic acid, ethylene glycol and isophthalic acid as main raw materials and used for injection molding and blowing of bottles by adding additives, and has the function of improving the heat absorption efficiency of the blowing process.

4 Product classification

PET resin for bottles can be divided into two categories according to different uses. food packaging and non-food packaging.

6 Test methods...

8 Marking and accompanying documents

8.1 Marking The outer packaging bags of PET resin products for bottles shall have obvious markings. The markings include. trademark, manufacturer name, manufacturer address, standard number, product name, brand, batch number (including production date) and net content, as well as warning signs for product protection and handling.

8.2 Accompanying documents When the products leave the factory, each batch of products shall be accompanied by a product quality inspection certificate. The certificate shall indicate the product name, designation, batch number, implementation standard, and be stamped with a special quality inspection seal.

9 Packaging, transportation and storage

9.1 Packaging The packaging of PET resin for bottles can be divided into bulk bags, tank trucks, container sea bags and other forms. The packaging bag of bulk bag products is a polyolefin woven bag lined with a polyethylene film inner bag and covered with a polyethylene dustproof film. The tank truck for transporting products shall be clean, dry and free of foreign matter.

9.2 Transportation PET resin for bottles is non-dangerous goods. There are no special requirements for transportation. However, certain protective measures shall be taken during transportation and loading-unloading to prevent the product from getting damp, contaminated, or damaged. The transportation vehicle shall be kept clean and dry, and equipped with a shed or tarpaulin. Sharp tools such as iron hooks shall not be used during transportation and loading-unloading. Mechanical collisions shall be prevented. During transportation, it must not be mixed with sand, broken metal, coal, glass, etc. It must not be mixed with toxic, corrosive or flammable materials. It shall not be exposed to the sun or rain. Loading and unloading operations must comply with warning sign regulations.

9.3 Storage PET resin for bottles shall be stored in a cool, dry, ventilated, clean warehouse equipped with fire-fighting facilities. Take dust prevention measures. When storing, keep away from heat sources and avoid direct sunlight. Do not pile in the open air.

Annex B

(normative) Preparation of density gradient columns - Batch method B.1 Reagents and materials Unless otherwise stated, only analytically pure reagents are used in the analyses. B.1.1 n-Heptane. analytically pure. B.1.2 Carbon tetrachloride. analytically pure. B.2 Instruments B.2.1 Density gradient tube. See

5.1.3 of GB/T 1033.2-2010. B.2.2 Magnetic stirrer. B.2.3 Erlenmeyer flask. capacity is 500 mL. B.2.4 Capillary funnel. inner diameter is about

0.5 mm; length is greater than the height of the density gradient tube. B.2.5 Measuring cylinder. capacity is 100 mL, 200 mL. B.3 Preparation of density gradient column for determination of PET resin density B.3.1 The density gradient column shall be prepared to ensure that the sensitivity of the density gradient column is not less than

0.001 g/cm3 per centimeter of column height. For example. the ideal density range for a gradient tube is

0.001 g/cm3 ~

0.1 g/cm