GB/T 38009-2019 PDF in English
GB/T 38009-2019 (GB/T38009-2019, GBT 38009-2019, GBT38009-2019)
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Spectacle frames -- Requirement and method for the detection of nickel release
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Standards related to (historical): GB/T 38009-2019
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GB/T 38009-2019: PDF in English (GBT 38009-2019) GB/T 38009-2019
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 11.040.70
Y 89
Spectacle frames - Requirement and method for the
detection of nickel release
(ISO/TS 24348:2014, Ophthalmic optics - Spectacle frames - Method for
the simulation of wear and detection of nickel release from metal and
combination spectacle frames, MOD)
ISSUED ON: AUGUST 30, 2019
IMPLEMENTED ON: MARCH 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Requirement ... 5
4 Method of wear simulation ... 6
5 Measurement of nickel release ... 12
6 Test report ... 18
Annex A (Informative) Articles made from materials releasing small amounts of
nickel ... 19
Annex B (Informative) Statistical uncertainty of the test procedure and
interpretation of results ... 21
Annex C (Informative) Production and treatment of reference discs ... 23
Bibliography ... 25
Spectacle frames - Requirement and method for the
detection of nickel release
1 Scope
This Standard specifies the requirement for the nickel release from the metal
parts of metal and combination frames, the method of wear simulation, the
measurement of nickel release, calculations, and test report.
This Standard applies to those spectacle frames which, if produced with
materials or surface treatments containing nickel.
2 Normative references
The following documents are indispensable for the application of this document.
For the dated references, only the editions with the dates indicated are
applicable to this document. For the undated references, the latest edition
(including all the amendments) are applicable to this document.
GB/T 14214 Spectacle frames - General requirements and test methods
(GB/T 14214-2003, ISO 12870:1997, MOD)
ISO 12870:2016 Ophthalmic optics - Spectacle frames - Requirements and
test methods
3 Requirement
Metal parts of metal and combination spectacle frames that come into
prolonged contact with the skin shall not have a nickel release greater than 0.5
μg/(cm2 • week).
Coated spectacle frames are tested in accordance with Clause 4 and Clause 5.
Spectacle frames, which are made of homogeneous alloy or pure metal and are
uncoated, are tested in accordance with Clause 5.
In accordance with the requirements of 4.2.3 in ISO 12870:2016, the parts to
be tested include:
- Rims of the spectacle frame;
- Nose bridge, brace bar, and other nasal-bearing surfaces, including metal
nose pads;
- Sides (excluding joints, zone around joints and protected by plastic end-
covers).
For spectacle frames made of nickel-containing materials with low nickel
release or nickel-containing surface treatment, see Annex A.
4 Method of wear simulation
4.1 Principle
The items to be tested are exposed to a corrosive atmosphere before being
placed in a tumbling barrel together with a wear medium of abrasive paste and
granules. The barrel is rotated so as to subject the test pieces to wear from the
wear medium. The items are then tested for nickel release in accordance with
Clause 5.
4.2 Reagents and materials
4.2.1 General
Except where indicated, all reagents and materials that can come into contact
with samples shall be free of nickel, and all reagents shall be of analytical grade
or better.
4.2.2 Reagents and materials for corrosion
4.2.2.1 Container
It can be closed; has a sample holder. All parts are made of inert materials (such
as glass or plastic).
4.2.2.2 Corrosive medium
TAKE 50 g of lactic acid (mass fraction>85%) and 100 g of sodium chloride;
DISSOLVE in 1000 mL of deionized water.
4.2.2.3 Degreasing solution
Choose neutral detergent and use it after proper dilution. It is also possible to
prepare a detergent, such as 0.5% (mass fraction) aqueous solution of sodium
dodecylbenzene sulfonate.
4.2.2.4 Deionized water
The conductivity of deionized water is not more than 1 μS/cm.
4.2.3.3 Abrasive paste, produced for dry-tumbling barrels and comprising:
- 6% to 8% ester wax of montanic acids - Wax E [CAS No. 73138-45-1];
- 3% octadecanoic acid (stearic acid) [CAS No. 57-11-4];
- 30% to 35% petroleum distillates, hydrotreated light paraffinic [CAS No.
64742-55-8];
- 2% polyethylene glycol cetyl/oleyl ether [CAS No. 68920-66-1] or
triethanolamine [CAS No. 102-71-6];
- 48% silicon dioxide (quartz) 200 μm mesh size [CAS No. 14808-60-7];
- 6% to 9% deionized water.
4.2.3.4 Granules, composed of outer shells of coconuts, walnuts, peanuts and
almonds, mixed in a ratio 1:1:1:1 by weight, ground and sieved to give a mixture
of particles having dimensions of between 0.8 mm and 1.3 mm.
4.2.3.5 Wear medium, composed of abrasive paste (4.2.3.3) and wear
granules (4.2.3.4) which are mixed as indicated in 4.5.1. Before use, the
required wear medium shall be conditioned in a laboratory for at least 24 h.
4.2.3.6 Retaining assembly, consisting of a threaded rod which carries three
hexagonal metal plates (Figures 2 and 3). The plate, A, is perforated with holes
of diameter 1.5 mm, or as appropriate, positioned 10 mm to 15 mm from the
edge of the plate, to take the ends of the tips of the sides. The plate, B, is
perforated with holes of diameter 5.0 mm, or as appropriate, positioned 10 mm
to 15 mm from the edge of the plate, to take the joint ends of the sides, together
with an aperture of 40 mm diameter to act as a filling hole. A silicone rubber
sheet is drilled with small holes matching the position of those in plate B; and
placed on one side of the plate B. Plate C has at least one hole for a threaded
rod. The nut is used to fix the plates and the distance between the plates.
According to the width of the front frame of the spectacle frame to be tested or
the length of the sides, adjust the distance between the plates A and B.
25
absorbent paper. After degreasing, samples should be handled with plastic
forceps or clean protective gloves.
Note 2: This degreasing stage is intended to remove extraneous grease and skin
secretions due to handling, but not any protective coatings.
4.4 Corrosion
Pour the corrosive medium (4.2.2.2) into the container (4.2.2.1); fix the sample
on the holder, so that the bottom of the sample is above the liquid level of the
medium. Cover the container and put it in an oven (4.2.2.5) at 50 °C for 2 h.
Remove the container from the oven and carefully open it under a fume hood.
Rinse the items with deionized water (4.2.2.4). Place on absorbent paper and
allow to dry at room temperature for about 1 h, then perform the wear procedure
specified in 4.5 without delay.
Note: This stage is for protective coatings (such as metallic coatings, lacquers and organic
coatings, etc.).
4.5 Wear
4.5.1 Preparation of wear medium
Weigh a sufficient quantity of wear granules (4.2.3.4) in order to fill the tumbling
barrel (4.2.3.1) to half its depth. Add 7.5 g of abrasive paste (4.2.3.3) for every
kilogram of wear granules and homogenize the wear medium by rotating in the
barrel for 5 h.
If the wear medium has not been used within 1 week, re-homogenize by rotating
it in the barrel for 1 h.
Note: This procedure coats the granules with the abrasive paste, forming the wear medium
that is used to simulate wear.
Keep the wear medium in a closed container until use and between uses.
After two wear procedures, add 7.5 g more of abrasive paste for every kilogram
of wear medium. Re-homogenize by rotating it in the barrel for a further 5 h.
After four wears, new wear media shall be replaced.
4.5.2 Attachment of test items
Attach the items inside the retaining assembly so that they cannot come into
contact with each other or collide with the barrel walls or other parts that could
cause damage during tumbling.
25
shall be free of nickel.
5.2.1 Deionized and aerated water: Fill a tall-form 2-L-beaker with deionized
water, specific conductivity ≤ 1 μS/cm. Attach a gas distribution tube to a cork
and position the lower end of the tube on the bottom of the beaker. Allow
grease-free air to flow at a rate of at least 150 mL/min for 30 min.
5.2.2 Sodium chloride.
5.2.3 Lactic acid: ρ=1.21 g/mL, greater than 85% (mass fraction).
5.2.4 Urea.
5.2.5 Ammonia solution: ρ=0.91 g/mL, 25% (mass fraction).
5.2.6 1% (mass fraction) ammonia solution: Place 10 mL of ammonia
solution (5.2.5) in a 250 mL beaker pre-filled with 100 mL of deionized water;
stir and cool to room temperature; transfer the solution into a 250 mL volumetric
flask and make up to volume.
5.2.7 Nitric acid: ρ=1.40 g/mL, 65% (mass fraction).
5.2.8 5% (mass fraction) nitric acid solution: Put 30 mL of nitric acid (5.2.7)
in a 500 mL beaker pre-filled with 350 mL of deionized water; stir and cool to
room temperature; transfer the solution into a 500 mL volumetric flask and make
up to volume.
5.2.9 Degreasing solution: Dissolve 5 g of sodium dodecylbenzene sulfonate
in 1000 mL of water; or use a properly diluted neutral detergent.
5.2.10 Wax or lacquer: It shall be able to prevent the release of nickel from
nickel-containing surfaces (test according to 5.5).
When coating one or more layers of wax or lacquer on the non-test surface of
the sample, it can prevent the nickel release from the non-test surface.
5.3 Apparatus
5.3.1 pH meter, accurate to 0.02 pH.
5.3.2 Analytical spectrometer, using atomic absorption spectrophotometry,
inductively coupled plasma spectrometry or equivalent methods. It can detect
the nickel concentration of 0.01 mg/L. After optimization, the instrument can
meet the following performance requirements a) and b):
a) Minimum precision: For a full matrix calibration solution with a nickel
content of 0.05 mg/L, the standard deviation of 10 measurements cannot
25
In order to avoid the nickel release on surfaces other than the test surface of
the sample, the non-test surface shall be removed or covered, to prevent
contact with artificial sweat solution. For example, after the sample is
degreased (5.2.9), apply more than one layer of wax or lacquer (5.2.10), which
can prevent the nickel release. The key points of selection and use are:
- The coating is effective and can prevent artificial sweat solution from
contacting non-test surfaces;
- Dry in the air after painting using a brush;
- Neither pollute artificial sweat solution nor interfere with nickel release and
analysis and testing;
- Safe to use;
- Not affect the physical and chemical properties of metal surface.
Non-test surfaces, which are not easy to remove or cover, shall be included in
the test area of sample.
If the uncovered non-test surface is included in the test area of sample, and the
nickel release result of the spectacle frame is unqualified, a new spectacle
frame can be taken; the non-test surface is covered; and the test is repeated.
5.4.2 Sample preparation
Gently swirl the sample for 2 min in degreasing solution (5.2.9) at room
temperature. Rinse with deionized water and dry. After degreasing, the
spectacle frame should be handled with plastic forceps or clean protective
gloves.
Note: This cleaning stage is intended to remove extraneous grease and skin secretions
due to handling, but not any protective coatings. However, it will also remove any
nickel contamination that might be present on the surface of the sample. If there is a
requirement to determine this nickel, the cleaning stage can be omitted. However,
note that omission of this cleaning stage might itself affect the nickel release from
the sample.
5.4.3 Reference disc
During each test, the amount of nickel release in the reference disc (see Annex
B and Annex C) is used for quality control. Before testing, both sides of the
reference disc shall be abraded. For each surface of the reference disc, first
use wet sandpaper with a particle size number of 600; then use wet sandpaper
with a particle size number of 1200 to grind at least 0.05 mm and then degrease
(5.2).
25
When tested according to this Standard, the nickel release of the reference disc
is (0.4±0.2)μg/(cm2 • week) (uncorrected).
5.5 Procedure
5.5.1 Preparation of artificial sweat solution
5.5.1.1 The solution representing the artificial sweat consists of deionized and
aerated water (5.2.1) containing:
- 0.5% (mass fraction) sodium chloride (5.2.2);
- 0.1% (mass fraction) lactic acid (5.2.3);
- 0.1% (mass fraction) urea (5.2.4);
- 1% (mass fraction) ammonia solution (5.2.6).
5.5.1.2 Weigh (1.00±0.01) g of urea, (5.00±0.01) g of sodium chloride and
(940±20) μL of lactic acid into a 1000 mL beaker. Add 900 mL of freshly
prepared deionized and aerated water and stir, until the added reagents are
completely dissolved. Calibrate the pH meter (5.3.1); insert the pH meter
electrode into the artificial sweat solution. Stir gently and carefully add 1%
(mass fraction) ammonia solution, until the pH stabilizes at (6.5±0.1). Transfer
the artificial sweat solution into a 1000 mL volumetric flask and make up the
volume with deionized and aerated water. Before use, make sure that the pH of
the artificial sweat solution is within the range of 6.4~6.6. The artificial sweat
solution shall be used within 3 h after preparation.
5.5.2 Release procedure
5.5.2.1 The sample is placed in a sealable container (5.3.4). According to
approximately 1 mL per square centimeter of the test area of the sample, add
the artificial sweat solution. The sample shall be completely soaked; but the
surface protected with wax or lacquer may not be soaked. Regardless of the
size of the sample test area, the amount of artificial sweat solution added is at
least 0.5 mL. Seal the container to avoid volatilization of artificial sweat solution.
The container shall be placed in a water bath or oven (5.3.3) at (30±2)°C for
168 h.
The reference disc shall be immersed in 3 mL of artificial sweat solution and
treated in the same way as the sample.
5.5.2.2 After one week, remove the sample from the artificial sweat solution and
rinse it with a small quantity of deionized water, adding the rinsing to the test
solution. Quantitatively transfer the test solution to an appropriately sized
25
Annex A
(Informative)
Articles made from materials releasing small amounts of nickel
For spectacle frames or parts made of homogeneous materials, it can be
considered that the nickel release of the measured surface of the sample is the
same as that of homogeneous materials. When the spectacle frame is made of
several different metals or alloys, whose nickel release after correction is less
than 0.5 μg/(cm2 • week), the nickel release of the part in contact with the skin
in the spectacle frame is likely to be less than 0.5 μg/(cm2 • week). However, it
is necessary for the manufacturer to inspect for the first time and periodically
check and confirm.
In a few cases, the nickel release from this type of composite material may
exceed 0.5 μg/(cm2 • week). The manufacturer has the responsibility to pay
attention to the occurrence of the following situations:
- There is an electrochemical reaction between nickel-containing alloy and
precious metal/alloy on the surface to be tested; bimetallic corrosion occurs.
For example:
1) Stainless steel with blunt edges due to low chromium or high sulfur is in
contact with more precious metals such as gold and platinum or high-
alloy stainless steel;
2) Stainless steel and silver-based alloy brazing;
- Change of surface condition as a result of welding, brazing, soldering or
other heat treatment; or damage to the surface in the course of assembly;
- Any degreasing, grinding or polishing operation that modifies the surface of
the frame.
When calculating the nickel release of regular-shaped and uniform nickel-
containing materials (such as discs), multiply it by a correction factor of 0.4; to
compensate for the deviation of the method in the reproducibility limit and the
repeatability limit. When calculating the nickel release of spectacle frames and
components, multiply it by a correction factor of 0.1; to compensate for the
deviations caused by the above-mentioned changes, coverage of non-test
surfaces, measurement of surface area in direct contact with the skin, and
irregular shapes.
25
Annex B
(Informative)
Statistical uncertainty of the test procedure and interpretation of results
Most chemical test methods are designed to measure the total amount of a
substance in a material. This usually makes it possible to obtain an accurate
result with close statistical agreement between laboratories because there is an
absolute or true value.
The method of this Standard determines the rate of release of soluble nickel
from the sample. With this type of chemical test, the result is dependent upon
the specified conditions of test, and there is no absolute or true value.
Consequently, it is more difficult to obtain close statistical agreement between
laboratories when performing such migration (or release) tests.
According to ISO 5725, in 1993, European laboratories were compared
according to the earlier edition of this method. Seven laboratories made
determinations on two homogenous materials of known area with nickel release
values of approximately 0.5 μg/(cm2 • week) and 1.5 μg/(cm2 • week). Results
were found to vary by up to 22% within laboratories and by up to 45% between
laboratories. These figures would be approximately three times higher if
adjusted to give a 95% confidence level [i.e. repeatability limit, r=0.33 μg/(cm2
• week) and reproducibility limit, R=0.68 μg/(cm2 • week) at the nickel release
of 0.5 μg/(cm2 • week)].
When the measurement result is close to the nickel release limit, the greater
uncertainty makes it difficult for manufacturers and authorities to determine
whether the product is qualified. This leads to inconsistency in the interpretation
of results.
There is no relationship between the nickel content and the release of soluble
nickel under standard test conditions. Therefore, it is not appropriate to
measure the nickel content and convert it into nickel release.
The parameters which are most likely to affect nickel-release results include:
measurement of the surface area; effectiveness of degreasing and any
“stopping-off”; temperature changes and composition of the artificial sweat,
especially its oxygen content; agitation or vibration of the sample; the surface
area of the test area to volume of artificial sweat ratio; and the way the sample
is suspended in the test solution. The incidence of surface defects also
influences the test result.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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