GB/T 29848-2018 English PDF (GBT29848-2018)

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GB/T 29848-2018: Ethylene-vinyl acetate copolymer (EVA) film for PV module
GB/T 29848-2018
Ethylene--vinyl acetate copolymer (EVA) film for PV module
GB/T 29848-2018
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 31.030
L 90
Replacing GB/T 29848-2013
Ethylene-vinyl acetate copolymer
(EVA) film for PV module
Issued on: December 28, 2018 Implemented on: April 01, 2019
Issued by: State Market Regulatory Administration;
Standardization Administration of PRC.
Table of Contents
Foreword ...3 
1 Scope ...6 
2 Normative references ...6 
3 Terms and definitions ...7 
4 Requirements ...8 
5 Test methods ...9 
6 Inspection rules ...26 
7 Packaging, marking, transportation, storage ...27 
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 29848-2013 “Ethylene-vinyl acetate copolymer
(EVA) film for PV module”.As compared with GB/T 29848-2013, the main
technical changes are as follows:
- MODIFY the scope of application (see clause 1; clause 1 of the 2013
version);
- MODIFY the normative reference (see clause 2; clause 2 of the 2013
version);
- ADD the terms and definitions of transparent EVA film, white EVA film,
surface density.DELETE the terms and definitions of EVA film, crosslinking
degree, shrinkage rate (see clause 3; clause 3 of the 2013 version);
- MODIFY the specification requirements, which is divided into transparent
EVA specifications, white EVA specifications.ADD the deviation of surface
density (see clause 4.1; clause 4.1 of the 2013 version);
- ADD the requirements of “no folding mark, no stain” in the appearance
requirements (see clause 4.2; clause 4.2 of the 2013 version);
- ADD the physical performance requirements of transparent EVA.CHANGE
the “indicators” in Table 2 of the 2013 version into the “transparent EVA
indicators”.DELETE the requirements for vinyl acetate content.MODIFY
the transmittance, peel strength, volume resistivity, UV-aging resistance,
high-temperature and high-humidity aging performance.CHANGE the
breakdown voltage strength into electrical strength.ADD the tensile
strength, elongation at break, tracking resistance index, dry-heat aging
performance (optional), UV high-temperature high-humidity aging
performance (optional), PCT aging performance (optional), (see clause 4.3;
clause 4.3 of the 2013 version);
- CHANGE the “requirements for specimen” into “test conditions”.MODIFY
the relevant requirements (see clause 5.2; clause 5.2 of the 2013 version);
- MODIFY the test method of thickness.ADD the test method of the deviation
of the surface density (see clause 5.3; clause 5.3 of the 2013 version);
- ADD the visual inspection method (see clause 5.4; clause 5.4 of the 2013
version);
- ADD the test method of the deviation of surface density (see clause 5.3.2);
Ethylene-vinyl acetate copolymer
(EVA) film for PV module
1 Scope
This standard specifies the terms and definitions, requirements, test methods,
inspection rules, packaging, marking, transportation and storage of ethylene-
vinyl acetate copolymer (EVA) film for photovoltaic module (hereinafter referred
to as EVA film).
This standard is applicable to EVA film for surface crystalline silicon photovoltaic
module.The film module may make reference to this standard.
2 Normative references
The following documents are essential to the application of this document.For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) are applicable to this standard.
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
GB/T 1040.1-2006 Plastics - Determination of tensile properties - Part 1:
General principles
GB/T 1040.3-2006 Plastics - Determination of tensile properties - Part 3: Test
Conditions for films and sheets
GB/T 1408.1-2016 Electrical strength of insulating materials - Test methods
- Part 1: Tests at power frequencies
GB/T 1410-2006 Methods of test for volume resistivity and surface resistivity
of solid electrical insulating materials
GB/T 2410-2008 Determination of the luminous transmittance and haze of
transparent plastics
GB/T 2790-1995 Adhesives, 180° peel strength test method for a flexible-
bonded-to-rigid test specimen assembly
GB/T 2828.1-2012 Sampling procedures for inspection by attributes - Part 1:
Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot
inspection
GB/T 2918-1998 Plastics - Standard atmospheres for conditioning and
testing
GB/T 4207-2012 Method for the determination of the proof and the
comparative tracking indices of solid insulating materials
GB/T 6672-2001 Plastics film and sheeting - Determination of thickness by
mechanical scanning
IEC 61215-2:2016 Terrestrial photovoltaic (PV) modules - Design
qualification and type approval - Part 2: Test procedures
ASTM E313-2010 Standard practice for calculating yellowness and
whiteness indices from instrumentally measured color coordinates
ASTM E424-71 (2015) Standard test methods for solar energy transmittance
and reflectance (terrestrial) of sheet materials
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Transparent EVA film
A film which uses the EVA resin as the main raw material, is added with
various additives, is formed by melt processing, has transparent appearance,
is used for terrestrial PV assembly.
3.2
White EVA film
A film which uses the EVA resin as the main raw material, is added with white
fillers and various additives, is formed by melt processing, has white
appearance, is used for terrestrial PV assembly.
3.3
Surface density
The EVA film mass per unit area.
According to the determination method of GB/T 1033.1-2008, determine the
density of the EVA film.Determine at least 3 groups for each specimen.Take
the average value.
5.4 Appearance
The appearance of EVA film shall, under the illumination of not less than 1000
lx, be subjected to visual inspection.It requires the observer to have normal
vision or corrected visual acuity of 0.8 or above.Lay the EVA film flatly on a
static workbench.The distance from the observer's eye to the observed
specimen does not exceed 0.6 m, to make observation at an angle of 45° to the
workbench.Check whether the film is flat, free of creases, stains, visible
impurities, or bubbles, has clear embossing.
5.5 Determination of physical performance
5.5.1 Luminous transmittance
5.5.1.1 Instrumentation
Spectrophotometer: It is equipped with an integrating sphere, the diameter of
which shall be greater than 90 mm.
5.5.1.2 Preparation of specimen
Take a piece of EVA film which has a size of 50 mm × 50 mm.From top down,
sequentially superimpose the front-panel material, the non-adhesive film, the
EVA film, the non-adhesive film, the back-panel material.Place it into the
vacuum laminating machine, allowing the front-panel to face downwards.
According to the curing temperature and time as required for the product, carry
out curing and crosslinking.Then take it out.Place it into a desiccator to cool it
to room temperature.Prepare for use.For the specimen as taken from the non-
adhesive film, the upper and lower surfaces shall be flat; the thickness shall be
uniform; the crosslinking degree reaches above 75%.The ...