GB/T 23988-2009 English PDF (GBT23988-2009)

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GB/T 23988-2009: Determination for abrasion resistance of coatings by falling abrasive
GB/T 23988-2009
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 87.040
G 50
Determination for abrasion resistance of coatings by falling
abrasive
ISSUED ON: JUNE 02, 2009
IMPLEMENTED ON: FEBRUARY 01, 2010
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Instruments and materials ... 4
4 Calibration ... 6
5 Sampling ... 7
6 Test plate ... 7
7 Operation steps ... 7
8 Result calculation ... 8
9 Test report ... 8
Bibliography ... 10
Determination for abrasion resistance of coatings by falling
abrasive
1 Scope
This Standard specifies the determination method for abrasion resistance of single-layer
or multi-layer coatings of paints, varnishes or related products.
This test method is applicable to the determination for abrasion resistance of single-
layer or multi-layer coatings of paints, varnishes or related products by dropping
abrasive materials on the coating. The abrasion resistance is expressed as the amount
of abrasive required to wear and tear a unit film thickness of the coating.
2 Normative references
The terms in the following documents become the terms of this Standard by reference
to this Standard. For dated references, all subsequent amendments (not including errata
content) or revisions do not apply to this standard. However, parties to agreements that
are based on this Standard are encouraged to study whether the latest versions of these
documents can be used. For undated references, the latest edition applies to this
Standard.
GB/T 3186, Paints varnishes and raw materials for paints and varnishes - Sampling
(GB/T 3186-2006, ISO 15528:2000, IDT)
GB/T 9271, Paints and varnishes standard panels for testing (GB/T 9271-2008, ISO
1514:2004, MOD)
GB/T 13452.2, Paints and varnishes - Determination of film thickness (GB/T
13452.2-2008, ISO 2808:2007, IDT)
GB/T 20777, Paints and varnishes - Examination and preparation of samples for
testing (GB/T 20777-2006, ISO 1513:1992, IDT)
3 Instruments and materials
3.1 Wear tester, as shown in Figure 1, with a switch near the top of the conduit to control
the flow of abrasive materials. It consists of a metal disc inserted into a narrow slit on
one side of the conduit with a collar covering the slit of the conduit. Firmly hold the
conduit in a vertical position on the top of a suitable container. There shall be a support
on the equipment for placing the painted sample at an angle of 45° to the vertical
5 Sampling
Take representative samples of the product under test (or each product in a multi-coating
system) in accordance with GB/T 3186.
Inspect and prepare test samples according to the provisions of GB/T 20777.
6 Test plate
6.1 Substrate
Unless otherwise agreed, the substrate shall be a hard substrate in accordance with the
provisions of GB/T 9271, such as metal plate or glass plate, with a minimum size of 70
mm × 150 mm.
6.2 Treatment and coating
Unless otherwise agreed, each substrate shall be prepared in accordance with the
provisions of GB/T 9271 and then painted using the method specified for the product
or system to be tested. At least two test plates shall be prepared for each sample.
6.3 Drying and conditioning
Dry and cure the coated test plate under the conditions specified for the product. Unless
otherwise specified, the sample plate shall be conditioned at (23 ± 2) °C and relative
humidity (50 ± 5) % for at least 24 hours before testing.
6.4 Coating thickness
Measure the thickness of the dry coating by one of the methods specified in GB/T
13452.2 and express in μm.
7 Operation steps
7.1 Unless otherwise agreed, the tests shall be carried out at a temperature of (23 ± 2) °C
and a relative humidity of (50 ± 5) %.
7.2 Mark a circular area with a diameter of approximately 25 mm on each test block
and position each circular area appropriately on the abrasion test plate support. Measure
the coating thickness according to the provisions in 6.4. At least 3 test points are
required for each circular area. Record the average measured value of the coating
thickness on each circular area.
7.3 Fix the coated test plate on the tester as described in 3.1. Adjust the test plate so that
the marked circular area is just below the center of the conduit; pour a certain volume
of standard sand into the funnel; turn on the switch; let the sand pass through the conduit
and hit the coated test plate. The container installed at the bottom of the tester collects
the fallen sand. Repeat the above operation until the coating is destroyed and the
substrate of an area of 4 mm diameter is exposed. During the test, the appropriate
incremental sand is 2 000 mL ± 20 mL. When approaching the end point, 200 mL ± 2
mL of sand can be added to the funnel.
Note 1: When the conduit is switched on, ensure that the collar covers the narrow slit
of the conduit opening.
Note 2: In order to ensure that the center of the sand beam falls exactly in the center of
the sand flow, check the centering of the conduit at regular intervals.
Note 3: The sand shall be replaced after passing through the instrument 25 times.
7.4 Repeat the tests of 7.1 ~ 7.3 on another test plate with the same coating.
8 Result calculation
Calculate the abrasion resistance of the test area of the coated test plate according to the
following formula:
Where:
A – abrasion resistance, in liters per micron (L/μm);
V – volume of abrasive material used, in liters (L);
T – coating thickness, in microns (μm).
Take the arithmetic mean of two parallel determinations as the result, with one decimal
place retained. The difference between the two parallel determinations shall be less than
25% of their average value.
9 Test report
The test report shall at least include the following:
a) a reference to this Standard (GB/T 23988);
b) details required to identify the product and abrasive material being tested;
c) test results expressed in accordance with Clause 8;