PDF GB/T 40911.2-2021 English
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Plastics - Poly(methyl methacrylate)sheets - Types, dimensions and characteristics - Part 2: Extruded sheets
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GB/T 40911.2-2021: PDF in English (GBT 40911.2-2021) GB/T 40911.2-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.140.10
CCS G 33
Plastics – Poly (methyl methacrylate) sheets - Types,
dimensions and characteristics - Part 2: Extruded sheets
(ISO 7823-2:2003, MOD)
塑料制品 聚甲基丙烯酸甲酯板材
ISSUED ON: NOVEMBER 26, 2021
IMPLEMENTED ON: JUNE 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 5
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions ... 7
4 Requirements ... 8
5 Additional properties ... 10
6 Test methods ... 11
7 Inspection rules ... 15
8 Marking, packaging, transportation and storage ... 17
Appendix A (Informative) Structural changes between this document and ISO 7823-
2:2003 ... 18
Appendix B (Informative) Technical differences between this document and ISO 7823-
2:2003 and the reasons ... 20
Plastics - Poly (methyl methacrylate) sheets - Types,
dimensions and characteristics - Part 2: Extruded sheets
1 Scope
This document specifies the requirements, test methods, inspection rules, marking,
packaging, transportation and storage for extruded colorless or colored, transparent,
translucent or opaque flat poly (methyl methacrylate) (PMMA) sheets.
This document applies to PMMA extruded sheets (hereinafter referred to as “sheets”)
with a thickness ranging from 0.3 mm to 20.0 mm.
This document does not apply to PMMA modified with elastomers.
2 Normative references
The following documents are normatively referenced in this document and are
indispensable for its application. For dated references, only the version corresponding
to that date is applicable to this document; for undated references, the latest version
(including all amendments) is applicable 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 1034-2008, Plastics - Determination of water absorption (ISO 62:2008, IDT)
GB/T 1040.2-2006, Plastics - Determination of tensile properties - Part 2: Test
conditions for moulding and extrusion plastics (ISO 527-2:1993, IDT)
GB/T 1043.1-2008, Plastics - Determination of Charpy impact properties - Part 1:
Non-instrumented impact test (ISO 179-1:2000, IDT)
GB/T 1633-2000, Plastics - Thermoplastic materials - Determination of Vicat
softening temperature (VST) (ISO 306:1994, IDT)
GB/T 1634.1-2019, Plastics - Determination of temperature of deflection under load
- Part 1: General test method (ISO 75-1:2013, MOD)
GB/T 1634.2-2019, Plastics - Determination of temperature of deflection under load
- Part 2: Plastics and ebonite (ISO 75-2:2013, MOD)
GB/T 2410-2008, Determination of the luminous transmittance and haze of
transparent plastics
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 (ISO 2859-1:1999, IDT)
GB/T 2918-2018 Plastics - Standard atmospheres for conditioning and testing (ISO
291:2008, MOD)
GB/T 3398.2-2008, Plastics - Determination of hardness - Part 2: Rockwell hardness
(ISO 2039-2:1987, IDT)
GB/T 3682.2-2018, Plastics - Determination of the melt mass-flow rate (MFR) and
melt volume-flow rate (MVR) of thermoplastics - Part 2: Method for materials
sensitive to time-temperature history and/or moisture (ISO 1133-1:2011, MOD)
GB/T 6672, Plastics film and sheeting - Determination of thickness by mechanical
scanning (GB/T 6672-2001, ISO 4593:1993, IDT)
GB/T 6673, Determination of length and width of plastics film and sheeting (GB/T
6673-2001, ISO 4592:1992, IDT)
GB/T 9341, Plastics - Determination of flexural properties (GB/T 9341-2008, ISO
178:2001, IDT)
GB/T 12027, Plastics - film and sheeting - Determination of dimensional change on
heating (GB/T 12027-2004, ISO 11501:1995, IDT)
GB/T 16422.2-2014, Plastics - Methods of exposure to laboratory light sources - Part
2: Xenon-arc sources (ISO 4892-2:2013, IDT)
GB/T 36800.2, Plastics - Thermomechanical analysis (TMA) - Part 2: Determination
of coefficient of linear thermal expansion and glass transition temperature (GB/T
36800.2-2018, ISO 11359-2:1999, IDT)
GB/T 39691-2020, Plastics - Determination of refractive index (ISO 489:1999,
MOD)
ISO 1628-6, Plastics - Determination of viscosity number and limiting viscosity
number - Part 6: Methyl methacrylate polymers
ISO 2818, Plastics - Preparation of test specimens by machining
3 Terms and definitions
The following terms and definitions are applicable to this document.
6 Test methods
6.1 General
6.1.1 Standard environment for specimen state conditioning and testing
Unless otherwise specified, the test specimens shall be conditioned at a temperature of
(23±2) °C and a relative humidity of (50±10) % in accordance with the provisions of
GB/T 2918-2018, for not less than 48 h, and shall be tested in this environment.
The test specimen for Vicat softening temperature shall be placed at (80±2) °C for not
less than 24 h, and then cooled to room temperature in a desiccator.
The test specimen for load deflection temperature shall be placed at (80±2) °C for 16 h
~ 24 h, and cooled to room temperature in a desiccator.
The measurement of dimensions of sheets shall be carried out at room temperature, but
in case of dispute, it shall be measured under the conditions of temperature (23±2) °C
and relative humidity (50±10) % specified in GB/T 2918-2018.
6.1.2 Preparation of test specimens
Unless otherwise specified, the specimens shall be prepared in accordance with the
provisions of ISO 2818. When it is necessary to process the sheets to the thickness
required for a particular test method, one original surface shall remain unchanged.
6.1.3 Thickness of test specimens
When the thickness of the sheet is less than the thickness of the specimen required in a
particular test method, a specimen of that thickness shall be used.
6.2 Appearance
Defects and their distribution shall be observed by irradiating the sheet with sunlight or
a light source with a color temperature of (6 500±650) K and sufficient brightness.
6.3 Color
Visually inspect.
6.4 Dimensions
6.4.1 length and width
According to the provisions of GB/T 6673, use a measuring tool with a division value
not greater than 1 mm to measure the length and width of the sheet at equal intervals
along the length and width of the test specimen, and measure each test specimen at least
4 times. Calculate the width limit deviation of the recorded data according to Formula
(1), and calculate the length limit deviation according to Formula (2).
Where:
ΔW – width limit deviation, in millimeters (mm);
Wmin or max – measured minimum or maximum width, in millimeters (mm);
W0 – nominal width, in millimeters (mm).
Where:
Δl – length limit deviation, in millimeters (mm);
lmin or max – measured minimum or maximum length, in millimeters (mm);
l0 – nominal length, in millimeters (mm).
6.4.2 Thickness
According to the provisions of GB/T 6672, use a measuring tool with a division value
not greater than 0.01 mm. Measurements shall be made at a distance not less than 10
mm from the edge of the sheet. Use the recorded data to calculate the thickness limit
deviation according to Formula (3).
Where:
Δe – thickness limit deviation, in millimeters (mm);
emin or max – measured minimum or maximum thickness, in millimeters (mm);
e0 – nominal thickness, in millimeters (mm).
min or max
min or max
min or max
6.4.3 Diagonal difference
Measure the lengths of the diagonals of the sheets respectively, and use a measuring
tool with a division value not greater than 1 mm to find the difference.
6.5 Tensile property
According to the provisions of GB/T 1040.2-2006, use 1B-type specimens, and the test
direction is consistent with the extrusion direction of the sheet. The test speed for tensile
strength and tensile strain at break shall be (5±1) mm/min, and the test speed for
modulus of elasticity shall be (1±0.2) mm/min.
6.6 Charpy impact strength
Test according to the provisions of GB/T 1043.1-2008/1fU. The recommended
specimen size is 80 mm × 10 mm × 4 mm. Specimens with a thickness less than 4 mm
shall be tested as per the original thickness of the specimen. The length direction of the
specimen is consistent with the extrusion direction.
6.7 Vicat softening temperature
Test according to the provisions of GB/T 1633-2000/B50. The test surface is the
original extruded surface of the sheet. The thickness of the specimen is 3.0 mm ~ 6.5
mm. The specimen that is too thick shall be processed into a specimen with a thickness
of 3.0 mm ~ 6.5 mm, and an original extruded surface of the sheet shall be retained.
The load is (50±1) N, and the heating rate is (50±5) °C/h. Before the test, the specimen
shall be placed at (80±2) °C for 24 h, and then cooled to room temperature in a
desiccator.
6.8 Shrinkage
According to the provisions of GB/T 12027, the heating temperature is (160±2) °C, and
the heating time is carried out according to Table 6. When the thickness of the specimen
is too large, prolong the cooling time in the desiccator until the specimen is cooled to
the ambient temperature.
6.9 Total light transmittance
Test according to method A in GB/T 2410-2008.
6.10 Light transmittance after xenon lamp aging
Measure according to GB/T 1634.1-2019 and method A in GB/T 1634.2-2019. The test
surface is the original extruded surface of the sheet. Before the test, the specimen shall
be placed at (80±2) °C for 16 h ~ 24 h, and cooled to room temperature in a desiccator.
6.16 Melt mass flow rate
According to the provisions in GB/T 3682.2-2018, use the test temperature of 230 °C
and the load of 3.8 kg. As for the specimen, use PMMA particles before sheet forming.
Dry the particles at (100±10) °C for no less than 20 minutes before the test, and carry
out the test immediately after the specimen leaves the oven.
6.17 Viscosity
Test according to the provisions of ISO 1628-6.
6.18 Haze
Test according to the provisions of method A of GB/T 2410-2008.
6.19 Refractive index
Test according to the method A of GB/T 39691-2020.
6.20 Density
Test according to method A (immersion method) of GB/T 1033.1-2008.
6.21 Water absorption
According to the provisions of method 1 of GB/T 1034-2008, the water temperature is
(23±1) °C, the soaking time is (24±1) h, and the recommended specimen size is 50 mm
× 50 mm, original thickness of the specimen.
7 Inspection rules
7.1 Batch
Products are accepted in batches. The continuously produced products – of the same
designation of raw material, the same length, width and thickness, the same formula,
and same process – shall be one batch, not more than 1 000 pieces.
7.2 Inspection classification
7.2.1 Delivery inspection
The ex-factory inspection items are appearance, dimensions and warping.
7.2.2 Type inspection
The type inspection items are all items in the basic requirements. In any of the following
cases, type inspection shall be carried out:
a) Trial type identification of new products or old products transferred to the factory;
b) After official production, if there are major changes in raw materials, formulas,
and processes, which may affect product performance;
c) Under normal production, it shall be carried out at least once a year.
d) When production which is suspended in long term for more than half a year is
resumed;
e) When the ex-factory inspection result is significantly different from the previous
type inspection result.
7.3 Sampling
Appearance and dimensional deviation shall follow the S-1 special inspection level on
single sampling plan stipulated in GB/T 2828.1-2012, and the acceptance quality limit
(AQL) is 6.5, as shown in Table 8.
7.4 Determination rules
7.4.1 Judgment of unqualified items
If the inspection results of appearance and dimensional deviation meet the requirements
in Table 8, judge it as qualified, otherwise judge it as unqualified.
If there are unqualified items in the basic performance test results, the double specimens
shall be taken from the original batch for a re-inspection of unqualified items. If there
are still unqualified test results, judge the item as unqualified.
7.4.2 Determination of a qualified batch
If all performance test results are qualified, judge the batch to be qualified, otherwise,
judge the batch to be unqualified.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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