IPC-TM-650 EN 2022 试验方法.pdf - 第647页
strips of filter paper on the surface of mineral salts agar. (Min- eral salt agar is identical to mineral salt solution, but contains an additional 15.0 g of agar per liter.) 5.1.6 The stock cultures may not be kept long…
1 Scope The fungus resistance test is used to determine
the resistance of materials to fungi and to determine if such
material is adversely affected by fungi under conditions favor-
able for their development, namely high humidity, warm atmo-
sphere, and presence of inorganic salts.
2 Applicable Documents None
3 Test Specimen Specimens must be a minimum size of
50 mm x 50 mm [1.97 in x 1.97 in] with copper foil (if appli-
cable) removed by etching using standard commercial prac-
tices.
4 Apparatus and Reagents
4.1 Test Chamber
The incubator shall be capable of main-
taining 30±1°C[86±2°F]and95±2%relative humidity
and have an ultraviolet (360 nm) source for subsequent
decontamination. Provisions shall be made to prevent con-
densation from dripping on the test item. There shall be free
circulation of air around the test item and the contact area of
fixtures supporting the test item shall be kept to a minimum.
4.2 Sterilizer
4.3 Centrifuge
4.4 pH Meter
4.5 Colony Counter
4.6 Incubator
4.7 Dishwasher
4.8 Petri Dishes
4.9 Filter Paper
4.10 Media Solutions
4.11 Microorganisms
4.12 Atomizer, 15,000 ± 3000 spores
5 Procedures
5.1 Preparation of Test Media
5.1.1 Mineral-Salts Solution
Prepare the solution to contain the following:
Potassium dihydrogen orthophosphate (KH
2
PO
4
) .......... 0.7g
Potassium monohydrogen orthophosphate (K
2
HPO
4
) ... 0.7g
Magnesium sulfate heptahydrate (MgSO
4
c7H
2
O) ........... 0.7g
Ammonium Nitrate (NH
4
NO
3
) ......................................... 1.0g
Sodium chloride (NaCl) .............................................. 0.005g
Ferrous sulfate heptahydrate (FeSO
4
c7H
2
O) ............... 0.002g
Zinc sulfate heptahydrate (ZnSO
4
c7H
2
O) .................... 0.002g
Manganous sulfate monohydrate (MnSO
4
cH
2
O) ......... 0.001g
Distilled water ........................................................... 1000 ml
Sterilize the mineral salt solution by incubating at 121 °C [250
°F] for a minimum of 20 minutes. Adjust the pH of the solution
by the addition of 0.01 normal solution of NaOH so that after
sterilization the pH is between 6.0 and 6.5. Prepare sufficient
salt solutions for the required tests.
5.1.2 Purity of Reagents Reagent grade chemicals shall
be used in all tests. Unless otherwise specified, it is intended
that all reagents shall conform to the specification of the Com-
mittee on Analytical Reagents of the American Chemical Soci-
ety, where such specifications are available.
5.1.3 Purity of Water Unless otherwise specified, refer-
ences to water shall be understood to mean distilled water or
water of equal purity.
5.1.4 Preparation of Mixed Spore Suspension
The following test fungi shall be used:
Description .................................................................. ATCC
Aspergillus niger ............................................................ 9642
Chaetomium globosum ................................................. 6205
Gliocladium virens ......................................................... 9645
Aureobasidium pullulans ............................................... 9348
Penicillium funiculosum ................................................. 9644
5.1.5 Maintain cultures of these fungi separately on an
appropriate medium such as potato dextrose agar. However,
the culture of Chaetomium globosum shall be cultured on
3000 Lakeside Drive, Suite 309S
Bannockburn, IL 60015-1249
IPC-TM-650
TEST METHODS MANUAL
Number
2.6.1
Subject
Fungus Resistance of Printed Board Materials
Date
03/07
Revision
G
Originating Task Group
Solder Mask Performance Task Group (5-33b)
Material in this Test Methods Manual was voluntarily established by Technical Committees of IPC. This material is advisory only
and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this
material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.
Equipment referenced is for the convenience of the user and does not imply endorsement by IPC.
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strips of filter paper on the surface of mineral salts agar. (Min-
eral salt agar is identical to mineral salt solution, but contains
an additional 15.0 g of agar per liter.)
5.1.6 The stock cultures may not be kept longer than four
months at6±4°C[43±7°F]atwhich time subcultures shall
be made and new stocks shall be selected from the subcul-
tures.
5.1.7 If genetic or physiological changes occur in the cul-
ture, obtain new cultures in accordance with 5.1.4. Sub-
cultures used for preparing new stock cultures or the spore
suspension shall be incubated at 30 °C±1°C[86°F±2°F]
for at least nine days.
5.1.8 Prepartion of Spore Suspension
5.1.8.1
Pour 10 ml of a sterile solution containing about
0.05 g/L of a nontoxic wetting agent such as sodium dioctyl
sulfosuccinate or sodium lauryl sulphate into one culture of
each fungus.
5.1.8.2 Use a sterile platinum or nichrome inoculating wire
to free the fungus from the culture medium by gently scraping
the surface growth of the agar from the culture of the medium.
5.1.8.3 Pour the spore suspension into a sterile 125-ml
glass-stoppered Erlenmeyer flask containing 45 ml of sterile
water and 50 to 75 solid glass beads, 5.0 mm [0.197 in] in
diameter.
5.1.8.4 Shake the flask vigorously to liberate the spores
from the fruiting bodies and to break the spore clumps.
5.1.8.5 Filter the dispersed fungal spore suspension through
a 6 mm layer of glass wool contained in a glass funnel and
collect into a sterile flask. This process should remove large
mycelial fragments and clumps of agar which could interfere
with the spraying process.
5.1.8.6 Centrifuge the filtered spore suspension and discard
the supernatant liquid.
5.1.8.7 Resuspend the residue in 50 ml of sterile water and
centrifuge.
5.1.8.8 Wash the spores obtained from each of the fungi in
this manner three times.
5.1.8.9 Dilute the final washed suspension with sterile
mineral-salt solution such that the resultant spore suspension
contains 1,000,000 ± 200,000 spores per ml as determined
with a colony counter.
5.1.9 Repeat the steps in 5.1.8 for each organism used in
the test and blend equal volumes of the resultant spore sus-
pension to obtain the final mixed spore suspension. The spore
suspension may be prepared fresh each day or may be held
at6±4°C[43±7°F]fornotmorethan seven days.
5.2 Viability of Inoculum Control With each daily group
of tests, place one piece of sterilized filter paper, 2.5 cm [1.0
in] square, on hardened mineral-salt agar in three separate
Petri dishes. Inoculate these dishes with the spore suspension
by spraying the suspension from a sterilized atomizer until
initiation of droplet coalescence. Incubate these at 30±1°C
[86 ± 2 °F] at a relative humidity not less than 85% and exam-
ine them after seven days of incubation. There shall be copi-
ous growth on all three of the filter paper control specimens.
Absence of such growth requires repetition of the test.
5.3 Control Items
5.3.1
In addition to the viability of inoculum control, known
susceptible substrates shall be inoculated along with the test
item to insure that proper conditions are present in the incu-
bation chamber to promote fungus growth.
5.3.2 The control items shall consist of 284.5 g/m
2
[8.25-oz]
bleached, scoured, 5 cm [2 in] long cotton duck strips, that
have been dipped into a solution containing 10% glycerol,
0.1% potassium dihydrogen orthophosphate (KH
2
PO
4
), 0.1%
ammonium nitrate (NH
4
NO
3
), 0.025% magnesium sulfate
(MgSO
4
7H
2
O), and 0.05% yeast extract (pH 5.3), from which
the excess liquid has been removed.
5.3.3 The strips should be hung to air dry before being
inoculated and placed into the chamber.
5.4 Inoculation of Test and Control Item
5.4.1
Mount the test and control items on suitable fixtures or
suspend from hangers. No cleaning of the test item shall be
permitted for 72 hours prior to the beginning of the fungus
test. Equipment handling prior to and during the fungus test
shall be accomplished without contamination of the equip-
ment.
IPC-TM-650
Number
2.6.1
Subject
Fungus Resistance of Printed Board Materials
Date
03/07
Revision
G
Page2of3
5.4.2 Precondition the chamber and its contents at: 30 ± 1
°C [86 ± 2 °F] and 95 ± 2% relative humidity for at least four
hours.
5.4.3 Inoculate the test and control items with the mixed
fungus spore suspension (5.1.4) by spraying it on and into the
test and control items (if not hermetically sealed) in the form of
a fine mist from a previously sterilized atomizer or nebulizer. In
spraying the test and control items, care should be taken to
spray all surfaces that are exposed during use or mainte-
nance. If the surfaces are nonwetting, spray until initiation of
droplet coalescence. Incubation is to be started immediately
following the inoculation.
5.5 Test Incubation of Test Items
5.5.1
Incubate test items at an air temperature of 30±1°C
[86 ± 2 °F] at 85% minimum relative humidity.
5.5.2 After seven days, inspect the growth on the control
items to be assured that the environmental conditions are
suitable for growth. If inspection reveals that the environmen-
tal conditions are unsuitable for growth, the entire test shall be
repeated.
5.5.3 If the control items show satisfactory fungus growth,
continue the test for a period of 28 days from the time of
inoculation, or as specified.
5.6 Evaluation
5.6.
Report those specimens which were found to be nutri-
ent to fungus growth.
5.6.2 Corrosion should be noted separately from the fungus
test results.
6 Notes
6.1 Source for Microorganisms
6.1.1
ATC
P.O. Box 1549
Manassas, VA 20108
(703) 365-2700
www.atcc.org
6.2 Secondary Sources for Microorganisms
6.2.1
Pioneering Research Division
U.S. Army Natick Laboratories
Natick, Massachusetts 01760
6.2.2 USDA, 1815 North University St., Peoria, IL 61604
6.3 After evaluation, the materials and the test chamber
must be decontaminated by exposure on all sides to ultra-
violet rays (360 nm) for a minimum of two hours, or sprayed
with a solution of 1:750 zephiran chloride solution. (One part
zephiran chloride to 750 parts distilled water.)
6.4 Safety Observe all appropriate precautions on MSDS
for chemicals involved in this test method.
6.5 Nutrient Agar Covered petri dishes containing nutrient
agar are considered to have the desired humidity. Covers on
larger dishes containing nutrient agar may need to be sealed
with masking tape.
IPC-TM-650
Number
2.6.1
Subject
Fungus Resistance of Printed Board Materials
Date
03/07
Revision
G
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