GB/T 24797.2-2022 English PDF (GBT24797.2-2022)
GB/T 24797.2-2022 English PDF (GBT24797.2-2022)
GB/T 24797.2-2022: Film for wrapping rubber bales - Part 2: Natural rubber
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
CCS B 72
Replacing GB/T 24797.2-2014
Film for wrapping rubber bales - Part 2: Natural rubber
(ISO 20299-2:2017, MOD)
ISSUED ON: OCTOBER 12, 2022
IMPLEMENTED ON: MAY 01, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
Introduction ... 6
1 Scope ... 7
2 Normative references ... 7
3 Terms and definitions ... 8
4 Material ... 8
5 Physical properties ... 8
5.1 Thickness ... 8
5.2 Density ... 8
5.3 Thermal properties... 8
6 Test report ... 8
This document is drafted in accordance with GB/T 1.1-2020 "Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents".
This document is Part 2 of GB/T 24797 "Film for wrapping rubber bales". GB/T 24797 has issued the following parts:
- Part 1: Butadiene rubber (BR) and styrene-butadiene rubber (SBR);
- Part 2: Natural rubber;
- Part 3: Ethylene-propylene-diene rubber (EPDM), acrylonitrile butadiene rubber (NBR), hydrogenated nitrile-butadiene rubber (HNBR), acrylic-ethylene rubber (AEM) and acrylic rubber (ACM).
This document replaces GB/T 24797.2-2014 "Film for wrapping rubber bales - Part 2: Natural rubber". Compared with GB/T 24797.2-2014, in addition to structural adjustments and editorial changes, the main technical changes are as follows: a) Change the description of the scope; clarify the applicable wrapping specifications (see Clause 1; Clause 1 of the 2014 edition);
b) Change the normative references (see 5.3.2 and 5.3.3; 4.2.2 and 4.2.3 of the 2014 edition);
c) Add the Clause "Terms and definitions" (see Clause 3);
d) Change the thickness representation unit; add the thickness gauge (see 5.1; 4.1 of the 2014 edition);
e) Add density requirements (see 5.2);
f) Change the requirements for peak melting temperature (see 5.3.3; 4.2.3 of the 2014 edition).
This document modifies and adopts ISO 20299-2:2017 "Film for wrapping rubber bales - Natural rubber".
Compared with ISO 20299-2:2017, this document has made the following structural adjustments:
- 5.1 and 5.2 correspond to 5.1 of ISO 20299-2:2017;
- Clause 6 corresponds to Clause 7 of ISO 20299-2:2017.
The technical differences between this document and ISO 20299-2:2017 and their reasons are as follows:
- Change the expression of the scope; change the mass of the bale from 33.33 kg to 33.3 kg (see Clause 1; Clause 1 of ISO 20299-2:2017); to comply with the provisions of GB/T 1.1-2020 and GB/T 8081-2018;
- Add the normative reference GB/T 1033.1-2008 (see 5.2), to specify the density determination method;
- Use GB/T 19466.3 to replace ISO 11357-3 (see 5.3.3), to adapt to the regulations in China on the use of differential scanning calorimetry (DSC) to determine melting temperature;
- Change "low-density polyethylene (PE-LD)" in film material TO "non-recycled low-density polyethylene (LDPE)" (see Clause 4; Clause 4 of ISO 20299-2:2017), to clearly specify the original state of the material;
- Add thickness gauge (see 5.1), to provide optional thickness measuring instrument; - Change "specific gravity" to "density"; add the determination method GB/T 1033.1-2008 of density (see 5.2; 5.1 of ISO 20299-2:2017); in order to use a standardized physical quantity term and specify its determination method. Because although ISO 20299-2:2017 specifies the specific requirements for the specific gravity of the film, it does not give a determination method;
- Delete the requirement for marking (see Clause 6 of ISO 20299-2:2017); because it conflicts with the specific provisions of GB/T 8082-2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing authority of this document shall not be held responsible for identifying any or all such patent rights.
This document was proposed by China Petroleum and Chemical Industry Federation. This document shall be under the jurisdiction of Subcommittee 8 on Natural Rubber, National Technical Committee 35 on Rubber and Rubber Products of Standardization Administration of China (SAC/TC 35/SC 8).
Drafting organizations of this document: Agricultural Products Processing Research Institute, Chinese Academy of Tropical Agricultural Sciences; Hainan Zhongxiang Technology Co., Ltd.; Hainan Natural Rubber Industry Group Jinxiang Co., Ltd.; Yunnan Natural Rubber Industry Group Jiangcheng Co., Ltd.; Xishuangbanna Sinochem Rubber Co., Ltd.; Guangdong Guangken Rubber Group Co., Ltd.
Main drafters of this document: Lu Guang, Yuan Ruiquan, Li Yimin, Yang Chunliang, Film for wrapping rubber bales - Part 2: Natural rubber
WARNING - Persons using this document should be familiar with normal
laboratory practices. This document does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.
This document specifies the material and physical property requirements for non- strippable low density polyethylene film for wrapping natural rubber bales. The function of the film is to keep the bales separated from each other during transportation and storage.
This document applies to each bale of block natural rubber of 33.3 kg or 35 kg; as well as to each bale of rubber ribbed smoked sheets of 33.3 kg, 35 kg, 50 kg, and 111.11 kg; or any other bale weights as mutually agreed between the relevant parties. 2 Normative references
The contents of the following documents, through normative references in this text, constitute indispensable provisions of this document. Among them, for dated references, only the edition corresponding to that date applies to this document. For undated references, the latest edition (including all amendments) applies to this document. GB/T 1033.1-2008 Plastics - Methods for determining the density of non-cellular plastics - Part 1: Immersion method, liquid pycnometer method and titration method (ISO 1183-1:2004, IDT)
GB/T 19466.3 Plastics - Differential scanning calorimetry (DSC) - Part 3: Determination of temperature and enthalpy of melting and crystallization (GB/T 19466.3-2004, ISO 11357-3:1999, IDT)
ISO 306:2013 Plastics - Thermoplastic materials - Determination of Vicat softening temperature (VST)
Note: GB/T 1633-2000 Plastics - Thermoplastic materials - Determination of vicat softening temperature (VST) (ISO 306:1994, IDT)