Some standard content:
JB/10242
Appendix A and Appendix B of this standard are both standard appendices; Appendix C is a suggestive appendix. This standard is proposed and managed by the National Technical Committee for Standardization of Metallic and Non-metallic Coatings. The responsible drafting unit of this standard is Yuejin Automobile Group Corporation. The participating drafting unit of this standard is Shenyang Guanxi Paint Co., Ltd. The main drafters of this standard are Chen Yuyan, Li Tong, Qian Wenzhong and Tang Hong. This standard is published for the first time.
1 Scope
Machinery Industry Standard of the People's Republic of China
General technical regulations of cathode electro-coating
General technical regulations of cathode electro-coatingJB/T 10242-2001
This standard specifies the definition of terms, the classification of cathode electro-coating, the selection of cathode electro-coating paint, the construction and management of cathode electro-coating, the requirements of cathode electro-coating for equipment, safety and environmental protection, etc. This standard applies to cathodic electrophoretic coating of metal workpieces 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T1724--1979 Determination of paint fineness Determination of paint film flexibility GB/T 1731-1993 GB/T 1732--1993 GB/T 1733--1993 GB/T 1747---1979 GB/T 1763--1979 GB/T 1764—1979 GB/T 1771--1991 GB/T 1865-—1997 GB/T 6739—1996 GB/T 6750—1986 GB/T 6751—1986
Determination of impact resistance of paint films
Determination of water resistance of paint films
Determination of ash content of coatings
Determination of resistance of paint films to chemical reagents
Determination of film thickness
Determination of neutral salt spray resistance of paints and varnishesArtificial ageing and artificial radiation exposure (filtered xenon arc radiation) of paints and varnishesDetermination of film hardness by pencil method
Paints and varnishes
Paints and varnishes
GB/T 6753.3—1986
Determination of density
Determination of volatile and non-volatile matter
Test method for storage stability of coatings
GB7691--1987Safety regulations for painting operationsLabor safety and labor hygiene management GB 7692--1999
Safety regulations for painting operationsSafety of pre-treatment process for painting and its ventilation and purificationGB/T82641987 Technical terms for painting
GB8978--1996 Integrated sewage discharge standardGB/T9286-1998 Cross-cut test for paint and varnish filmGB/T9751-1988 Determination of viscosity of coatings at high shear ratesGB/T9754-1988 Determination of 20°, 60° and 85° specular gloss of paint and varnish films without metallic pigmentsGB16297--1996 Integrated emission standard for air pollutantsDetermination of conductivity of electrophoretic paint
HG/T 3335-1977(85)
HG/T 3337—1997(85)
Determination of coulometric efficiency of electrophoretic paint
Approved by China Machinery Industry Federation on May 23, 2001 and implemented on October 1, 2001
3 Definitions
JB/T 10242—2001
This standard adopts the definitions in GB/T8264 and the following definitions. 3.11. Effect leffecl
The effect of electrophoretic paint on horizontal and vertical surfaces. 3.2 MEQ Neutralizer MEQ
The number of moles of neutralizer consumed by electrophoretic paint with a solid content of 100g. 3.3 Redissolving
The ability of electrophoretic wet film to dissolve again in the electrophoretic tank liquid. It is expressed as the percentage of the dissolved film thickness within a specified time to the total film thickness. 3.4 Loss on heating
When the electrophoretic coating film of 105 (120°C) is heated to the drying temperature to achieve full drying, low molecular weight compounds are thermally decomposed, resulting in the weight loss of the coating film. 4 Classification of cathodic electrophoretic coating
According to its use, it can be divided into two categories:
) Cathodic electrophoretic base coating mainly for improving corrosion resistance. It is used for shells and some related parts of automobiles, refrigerators, washing machines, etc.
h) Cathodic electrophoretic coating mainly for decoration, specially used for decorative coating protection and decorative metal protection. Such as metal eyeglass frames, watches, decorative hardware products, household appliances, building materials, etc. 5 Selection of cathodic electrophoretic coating
5.1 Selection principles
5.1.1 Determine the category of electrophoretic coating according to the type of product to be coated and the country where the electrophoretic coating is used. 5.1.2 Select the required variety according to the requirements of the coated product for the electrophoretic coating. 5.1.3 Conduct various performance comparison tests on the selected electrophoretic coatings. Through the test, understand the quality of the electrophoretic coating film, the stability of the electrophoretic tank liquid, the width of the construction window, etc.
5.1.4 The cathode electrophoretic base coating should be tested for compatibility with related coatings such as phosphating film, mid-coat coating, underbody coating, sealant, topcoat, etc. Decorative electrophoretic coatings should be tested for adaptability to the surface of the coated object. 5.1.5 Understand the technical strength and after-sales service level of the coating manufacturer during the selection test. 5.2 Sample performance test
Perform performance tests according to the contents specified in the enterprise standards of the user unit or the contents specified in the product manual. Coating properties in supply status (see Table 1)
Table 1 Coating properties in supply status
Solid content
Storage stability
mPa·s
Technical indicators
Determined by negotiation between the supplier and the buyer
Test method
GB/T 675
GB/T 9751
GB/T6750
GBT1724
GB/T6753.3
Working fluid properties (see Table 2)
Solid content
Conductivity
MEQ value
Solvent content
Coulomb efficiency
Voltage/film thickness
Destruction voltage
Throwing power
Redissolution rate
L effect
Heating loss
Battery fluid stability during accelerated aging
Environment Stability of tank liquid at temperature
Bacterial growth
Performance of coating film (see Table 3)
Appearance of coating film
Gloss (60° mirror gloss)
Impact resistance
Flexibility
Water resistance (40℃×500h)
JB/T10242--2001
Table 2 Performance of working liquid
Technical indicators
According to the requirements of coating types
According to the requirements of coating types
Viμrn
Acid resistance (0. 05mol/H.S0),×8 h)Alkali resistance (0.1mol/NaOH×8h)
Scratching test (1 mm)
Salt spray resistance of swimming board
Salt spray resistance
Stone impact resistance
Aging resistance
Abrasion resistance
Sweat resistance
! ) Instrument for decorative electrophoretic coating
According to the requirements of the coating variety
According to the requirements of the coating variety
According to the requirements of the coating variety
According to the requirements of the coating variety
As needed.Determine ED curve, select the best voltage film thickness value higher than construction voltage 30V
According to coating type requirements
Horizontal and vertical coatings are flat, smooth, without abnormal appearance, and there is no obvious difference in film thickness
Voltage reduction ≤40
Voltage reduction ≤40
Coating performance
Technical indicators (example)
Flat, smooth, without abnormality
According to coating type requirements
No change in coating
No change in coating
Light change in coating
According to user requirements
According to user requirements
According to user requirements
According to user requirements
According to user requirements
Test method
GB/T 6751
HG/T 333
GB/T 1747
Appendix A A
Phase chromatography
HG/T 3337
Appendix A AI
Appendix A A3
Appendix A AIO
Appendix A A2
Appendix A Ai
Appendix A A3
Appendix A A?
Appendix A A8
Appendix A AII
Test method
GB/T 9754
GB/T 6739
GB/T1732
GB/T1731
GB/T1733
GB/T 1763
GB/T1763
GB/T 9286
Appendix A A9
GB/T 1771
(single-side corrosion shall not exceed 2mm)
Appendix 3
GB/T 1865
negotiated by both parties
negotiated by both parties
6 Construction and management of cathodic electrophoretic coating
6.1 Typical process flow of cathodic electrophoretic coating
Electrophoretic coating
Fresh pure water spray
0 water washing
JB/T 10242-~2001
Multi-stage UF water washing
Drying
Note: For decorative coating, it shall be adopted according to the actual situation. 6.2 Requirements for workpieces before cathodic electrophoretic coating: a) no oil, rust, iron powder, phosphating residue and other foreign matter attached; b) the conversion film is uniform, dense, and free of abnormalities, meeting the corresponding technical requirements; c) the dripping water conductivity of the workpiece is ≤30μs/cm. 6.3 Control of cathode electrophoretic coating process (see Table 4) Table 4
Ultrafiltration (UF)
0 water washing
UF water washing
Tannel liquid temperature
Each section voltage
Each section current value (max)
Management conditions
Electrophoresis time (time for workpiece to be fully immersed) Main tank and auxiliary tank liquid level difference
Anodic liquid conductivity
Anodic liquid state
Circulating pump pressure
UF filtrate penetration
Membrane pressure difference
UF filter pressure difference
UF pump pressure
Multi-stage UF water washing
Spray pressure
Filter pressure difference
Fresh UF F water washing
Spraying pressure
Filter pressure difference
UF filtrate supply
Fresh UF water spraying
Cathode electrophoretic coating process control
Multi-stage pure water washing
Control range
Within the range specified by the paint variety
Within the range specified by the paint variety
Within the range specified by the paint variety
Primer coating: 2~3
Decorative coating: Depends on the actual situation cm
μs/cm
300~1000
No turbidity
Equipment design requirements
Within the design specified index range
-Generally 1.0~1.2 L/(m2min)）
Within the range required by the equipment
0.13~0.15
According to the requirements of the equipment
Spray cleaning within 1min after leaving the tank.
Can be sprayed evenly on the entire workpiece surface 0.1±0.02
According to the requirements of the equipment
0. 12 : 0. 05
According to the requirements of the equipment
According to the output,
Generally].0~～~1.2［（m
Pure water washing
JB/T 10242—2001
Table 4 (end)
Management conditions
Spray pressure of multi-stage pure water washing tank
Filter pressure difference
Fresh pure water washing spray pressure
Filter pressure difference
Fresh pure water supply
Natural drip drying
Segment setting temperature
Cleaning frequency
Management of cathode electrophoresis tank liquid process parameters
Electrophoresis tank liquid process parameters (see Table 5)
Weight
Conductivity
MEQ value
Solvent content
Dissolution rate
Coulomb efficiency
Throwing power
Voltage membrane thickness
Filter residue
Control range
0. 12±0. 05
According to equipment requirements
0. 1± 0. 02
According to equipment requirements
Generally 1.0~1.2 1/(m2·min)
According to production
Setting value required by coating type
According to actual situation
Table 5 Electrophoresis tank liquid process parameters
Control index
According to the type of cathode electrophoresis
Coating index control
6.4.2 The tank liquid should be adjusted every day according to the test results. Inspection method
GB/T 6751
HG/T3335
GB/T 1747
Appendix A A4
Gas chromatography
Appendix A A2
HG/T3337
Appendix A A10
Appendix A A1
400 months
6.5 Maintenance and management of cathode electrophoretic coating line Equipment inspection should be carried out every day according to the operation requirements of the equipment (specific requirements depend on the equipment conditions). 6.5.1
Visual management of the electrophoretic coating line should be carried out every day (see Table 6). Table 6 Visual management of the electrophoretic coating line
Inspection items
Flow of the electrophoretic tank liquid surface
Foaming of the UF washing line
Turbidity of the UF liquid
Abnormal state
Slow flow rate, foam is difficult to overflow
Foam overflows the washing line
①The color of the filtrate is turbid
②Self-colored crystals are attached to the flow meter
①The circulation pump inlet is blocked;
②The filter element is blocked;
③The riser and nozzle are blocked
①The nozzle water pressure is too high;
②The liquid level of the washing tank is too high
The UF tube is damaged
There is lead carbonate in the filtrate
Inspection frequency
|times/day
1 time/day
2 times/week
1 time/day
1 time/half month
1 time/half month
1 time/half month
1 time/day
When membrane abnormality is found
2 times/week
Inspection frequency
2 times! Day
Inspection items
Anode liquid turbidity
51Coating state
Coating color after drying
JB/T10242—2001
Table 6 (end)
Abnormal state
①Anode liquid color is turbid
②) There are
White algae floating in the diaphragm electrode or in the anode liquid tank
①Pit
③Particles
Occurrence of a sagging|| tt||① Impurities generated
① Glossy, slightly whitish
② Too low gloss, yellowing
Product coating inspection (see Table 7)
Test items
Coating appearance
Coating film
On-line sample cross-cut test
Dryness
Diaphragm rupture
Bacteria in the anode liquid
) Before or after coating - Oil or impurities attached 1 Bubbles attached in the coating;||t t||Silicone pollution
Dust before or after painting:
(Chemical residue before painting; Coagulation in the paint
TIncreased water concentration in washing water:
Poor washing effect
①Poor washing after chemical treatment:
②Contaminants dropped from the conveyor chain and hanger:?Pollution in the drying room
Incomplete drying
Overbaking
Table 7 Product coating inspection items
Control index
Flat, smooth, complete, no abnormality
Control index is set to level 0 according to the requirements of the workpiece to be coated
No loss of gloss, no fading
Basic requirements for equipment for cathode electrophoretic coating Basic requirements for equipment for cathode electrophoretic coating are shown in Table 8. Table 8 Basic requirements for cathode electrophoretic coating equipment System
Electrophoresis tank
Tan liquid circulation
Filtration method
Detection method
GB/T 1764
GB/T 9286
Appendix A A12
Inspection frequency
Inspection frequency
2 times/day
2 times/day
Design according to the specific conditions of the workpiece and the transportation method. The inner wall of the tank is required to be reliably insulated, with a breakdown voltage of 20kV. Pump type: low-speed double mechanical seal (UF filtrate liquid seal); paint circulation stirring times: 4~10 times? h: Nozzle: preferably a jet-type efficiency-enhancing nozzle:
Circulation method and flow rate: the flow method of the tank liquid is consistent with the movement direction of the workpiece, and the surface flow speed is greater than the movement speed of the workpiece
Filter type: filter element filter or bag filter: Filtration accuracy: 25~50μm
Electrification conditions
UF water washing
Post-water washing
Drying furnace
JB/T 10242—2001
Table 8 (End)
()Diaphragm structure: The protective frame should be made into a structure to prevent pigment precipitation: ②Electrode material: Diaphragm electrode→stainless steel plate or rod: ③Diaphragm material: Ion exchange diaphragm matching electrophoretic coating: DAnode liquid flow rate: 513［nin;
?Anode liquid pH value: 2-~3.2
?Anode liquid conductivity: 300~1000μs/cm①Model: Various UF equipment and UF membrane matching electrophoretic coating; It is necessary to design a UF membrane backwash device:
! ③UF filtrate permeation of ultrafiltration system: calculated according to the conditions of output, shape of parts, concentration of tank liquid, requirements for UF water, etc., the UF device should be cleaned when the barrier is lowered by 70:
①Solid content and appearance of ultrafiltrate: 0.1%~1% solid yellow transparent liquid①Power supply method: preferably full immersion 2-stage power supply:②Rectifier: Fluctuation rate: within 10%,
Capacity: to be determined according to the size of the workpiece and production conditions:③Pole ratio: anode/cathode = 1/4~5;
①Inter-pole distance: minimum 50c m:
?Backup power supply: can ensure the normal operation of electrophoretic paint circulation stirring, ultrafiltration system and pure water device (DRecovery section number: 4 sections (spray → flood wash → spray + drain): ②Prevent foam: tank/spray chamber-body; spray pressure control ≥0.1MPa:
?Prevent particles: precision filtration accuracy is 25~50um①pH adjustment: to prevent paint agglomeration, the pH value of washing water is controlled at pH=5~6;②Solid content management: the solid content of washing water is controlled below 0.1%①Heating method: preferably indirect Connect to the heating bridge furnace; ② Heating time: overflow ≥ 10min· insulation 20min (designed according to production volume): ③ Heating temperature: according to the workpiece temperature required by the electrophoretic coating used. Conveying system
Material system
①) Conveying chain: The electrophoretic suspension chain must be installed to facilitate cleaning and a large enough oil collecting tray: ② Conveying method: two types of straight up and down and continuous passing can be selected (I) Non-neutralized two-component low-viscosity coatings are directly put into the tank after stirring (the slurry should be stirred evenly in the original barrel and then diluted and added to the auxiliary tank): @) Neutralized single-component high-viscosity paint is first mixed with the tank liquid to form a paint liquid with 30% to 40% solid content, and then added to the auxiliary tank after stirring. ①) The phosphated workpiece must enter the electrophoresis tank in a fully wet or fully dry state; ) The storage chain, transfer chain and transmission chain between phosphating and electrophoresis should be equipped with closed channels to prevent dust and oil pollution in the air: C) The electrophoresis system must use special lubricants that do not contain silicon and chemicals that do not cause shrinkage. 599
8 Safety and Environmental Protection
JB/T10242-2001
Power grounding. The workpiece is powered on using a separate power rail. 8.1
8.2 The anode system of the electrophoresis tank must ensure good conductivity to prevent electric shock. 8.3 Wastewater treatment of the cathode electrophoresis system. The cathode electrophoresis paint manufacturer should provide the composition and displacement of the wastewater to ensure that the wastewater treatment plant in the painting workshop is centrally and uniformly treated. After treatment, it should comply with the provisions of GB8978. 8.4 The exhaust gas discharged from the cathode electrophoretic coating system shall be treated. The cathode electrophoretic coating manufacturer shall provide the composition and discharge volume of the exhaust gas, and install the corresponding catalytic combustion exhaust gas treatment device or direct combustion device on the drying tunnel according to the data. After treatment, it shall comply with the provisions of GB16297. 8.5 The rectifier system of cathode electrophoretic coating shall be separately installed in the enclosure facilities and managed by a dedicated person. 8.6 The process safety and labor hygiene of cathode electrophoretic coating shall comply with the relevant provisions of GB7692 and GB7691. 600
A1 Voltage/film thickness determination
A1.1 Overview
JB/T 10242—2001
Appendix A
(Appendix of the standard)
Method for determining the performance of cathode electrophoretic coating
By changing the voltage for electrophoretic coating, the film thickness is measured, and the voltage/film thickness relationship curve is drawn to obtain the corresponding voltage for the optimal film thickness. A1.2 Test instruments and materials
) A set of electrophoretic coating equipment (including electrophoretic tank, rectifier, drying box, etc., the same below); b) Test plate: phosphating plate of the same material as the product on the production line; specification: 70mm×150mmX0.8mm. A1.3 Operation steps
a) Select a few voltage points in advance;
b) Under the selected voltage, perform electrophoretic coating and drying according to the process parameters specified for the electrophoretic coating to be tested; () After drying, measure the film thickness of each test plate and make the following voltage/film thickness relationship curve (as shown in Figure A1). A1.4 Result evaluation
From the obtained voltage/film thickness relationship curve, the corresponding voltage of the optimal film thickness is obtained. Film thickness/μm
Voltage: V
Optimum film thickness corresponding voltage
Figure A1 Voltage/film thickness relationship curve
Note: When measuring voltage/film thickness, the data will differ due to the difference in coating temperature, coating stirring speed, and anode and cathode area ratio. The above parameters should be specified according to the requirements of the coating to be tested.
A2 Determination of re-dissolution rate
A2.1 Overview
After the test plate is electrophoretically coated under specified conditions, the lower half of the wet coating is immersed in the electrophoresis tank liquid for a specified time, then taken out and dried, and the film thickness of the upper and lower coatings is measured. The lower and upper film thicknesses are compared to calculate the re-dissolution rate (%). A2.2 Test instruments and materials
a) One set of electrophoretic coating equipment;
b) Coating thickness gauge (measuring range of 0~500μm); r) Test plate: phosphated plate of the same material as the products on the production line; specification: 70mm×150mm×0.8mm. A2.3 Operation steps: 1. Electrophoretically coat the test plate in the electrophoretic bath to be tested under the specified conditions. After washing with water, immediately immerse the lower half of the coating in the stirred electrophoretic bath; 2. Take out the test plate and dry it under the specified conditions of the electrophoretic coating to be tested: 3. Measure the coating thickness of the upper and lower parts of the test plate according to GB/T1764: 4. Repeat the above operation three times and take the average value. A2.4 Calculate according to formula (AI): 5. Where: ... redissolution rate; 6. The film thickness of the upper part.um; 7. The film thickness of the lower part.m. Determination of the destruction voltage of electrophoretic coatings: 8. 100%
（AI）
A3.1 Overview
The tested coating is electrophoretically coated, and the voltage is gradually increased in 10V intervals to obtain the voltage when the coating film is damaged, also known as the breakdown voltage.
A3.2 Test instruments and materials
a) Electrophoretic coating constant temperature device·set;
b) Test plate: phosphate plate of the same material as the product on the production line; specification: 70mm×150mm×0.8mm. A3.2 Operation steps
Electrophoretic coating is performed according to the voltage specified for the electrophoretic coating to be tested. The voltage is increased in 10V intervals until the coating film is damaged. With the damage of the coating film, the bath temperature will rise sharply, so a constant temperature device is required. The bath temperature is controlled at 28℃±1℃. The test is repeated more than twice. Except for the voltage, other coating conditions should be the same. A3.4 Nesting evaluation
The lowest destruction voltage among the data obtained by repeating the operation more than twice is taken as the "destruction voltage" of the electrophoretic coating. The coating within 5mm of the submergence line is not the object of evaluation. A4 Determination of MEQ value of electrophoretic coating
A4.1 OverviewbZxz.net
The electrophoretic coating with tetrahydrofuran added is titrated with potassium chloride ethanol standard solution. Calculate the moles of neutralizer consumed by 100g solid content of electrophoretic coating.
A4.2 Test instruments and materials
a) Beaker: 100ml.
b) Measuring cup: 50ml;
（）Precision balance: accurate to o.1mg:
d) 0.1mol/l potassium hydroxide ethanol standard solution;
//) THF (tetrahydrofuran);
//) Potentiometric titration device.
A4.3 Operation steps
a) Accurately weigh about 10g of electrophoresis tank liquid sample and put it into a 100ml beaker;
h) Add 50mL of THF solution to the above sample and connect it to the potentiometric titration device;
//) Titrate the obtained sample solution with 0.1mol/l potassium hydroxide ethanol standard solution, and the end point is determined by the potential curve;
Calculate the MEQ value according to formula (A2):
IB/T 10242-2001
Wherein: V is the number of milliliters of potassium hydroxide ethanol standard solution consumed in titration, ml; N is the concentration of potassium hydroxide ethanol standard solution, molL: G
The mass of the electrophoresis tank liquid sample, g;
The solid content of the electrophoresis tank liquid sample.
A5 Determination of heating loss
. (A2)
A5.1 Overview
The electrophoretic coating film is subjected to 105 (or 120°C to remove moisture and solvent, and then further heated to the drying temperature to make the coating film dry, and the mass of the coating film is measured. Calculate the heating loss. A5.2 Test instruments and materials
) One set of electrophoretic coating equipment:
h) Precision balance (accuracy 0.1mg); () Test plate: Phosphate plate of the same material as the product on the production line; Specification: 70mm×150mm×0.8mm; d) Electric heating blast drying oven (control error ±1℃C). A5.3 Operation steps
a) Use a balance to accurately weigh three test plates and record the weight W respectively. ; b) Carry out electrophoretic coating to achieve the standard film thickness, and let it stand for a long time after washing (more than 1h); c) After draining, The electrophoresis plate is baked at 120℃ for 1h or 105℃ for 3h, cooled in a dryer, and accurately weighed, Wl; d) The test plate is continued to be baked at the drying temperature required by the coating for 20min, taken out and placed in a dryer for cooling, and accurately weighed, and the mass W is recorded respectively.
A5.4 Calculation
Calculate the heating loss according to formula (A3) and take the average value. Heating loss-WW
武: w
Mass of the test plate before electrophoresis, g;
W.Mass of the test plate after baking at 120C or 105C, g; W
Coating solidification The final test plate mass is g.
A6L effect determination
(A3)
A6.1 Overview
Use the electrophoretic coating 1. Shaped test plate method to check the coating quality on the horizontal and vertical surfaces of the coated object and measure the electrophoretic effect of the coating. A6.2 Test instruments and materials
a) A set of electrophoretic coating equipment;
b) Test plate: Phosphate plate of the same material as the product on the production line: specification 70mm×150mmX0.8mm Fold into a right angle at 60mm from the lower end of the long side according to Figure A2. And process according to the specified phosphating process. Figure A24 Nesting evaluation
The lowest destruction voltage among the data obtained by repeating the operation more than twice is taken as the "destruction voltage" of the electrophoretic coating. The coating within 5mm of the submergence line is not the object of evaluation. A4 Determination of MEQ value of electrophoretic coating
A4.1 Overview
The electrophoretic coating with tetrahydrofuran added is titrated with potassium chloride ethanol standard solution. Calculate the moles of neutralizer consumed by 100g solid content of electrophoretic coating.
A4.2 Test instruments and materials
a) Beaker: 100ml.
b) Measuring cup: 50ml;
（）Precision balance: accurate to o.1mg:
d) 0.1mol/l potassium hydroxide ethanol standard solution;
//) THF (tetrahydrofuran);
//) Potentiometric titration device.
A4.3 Operation steps
a) Accurately weigh about 10g of electrophoresis tank liquid sample and put it into a 100ml beaker;
h) Add 50mL of THF solution to the above sample and connect it to the potentiometric titration device;
//) Titrate the obtained sample solution with 0.1mol/l potassium hydroxide ethanol standard solution, and the end point is determined by the potential curve;
Calculate the MEQ value according to formula (A2):
IB/T 10242-2001
Wherein: V is the number of milliliters of potassium hydroxide ethanol standard solution consumed in titration, ml; N is the concentration of potassium hydroxide ethanol standard solution, molL: G
The mass of the electrophoresis tank liquid sample, g;
The solid content of the electrophoresis tank liquid sample.
A5 Determination of heating loss
. (A2)
A5.1 Overview
The electrophoretic coating film is subjected to 105 (or 120°C to remove moisture and solvent, and then further heated to the drying temperature to make the coating film dry, and the mass of the coating film is measured. Calculate the heating loss. A5.2 Test instruments and materials
) One set of electrophoretic coating equipment:
h) Precision balance (accuracy 0.1mg); () Test plate: Phosphate plate of the same material as the product on the production line; Specification: 70mm×150mm×0.8mm; d) Electric heating blast drying oven (control error ±1℃C). A5.3 Operation steps
a) Use a balance to accurately weigh three test plates and record the weight W respectively. ; b) Carry out electrophoretic coating to achieve the standard film thickness, and let it stand for a long time after washing (more than 1h); c) After draining, The electrophoresis plate is baked at 120℃ for 1h or 105℃ for 3h, cooled in a dryer, and accurately weighed, Wl; d) The test plate is continued to be baked at the drying temperature required by the coating for 20min, taken out and placed in a dryer for cooling, and accurately weighed, and the mass W is recorded respectively.
A5.4 Calculation
Calculate the heating loss according to formula (A3) and take the average value. Heating loss-WW
武: w
Mass of the test plate before electrophoresis, g;
W.Mass of the test plate after baking at 120C or 105C, g; W
Coating solidification The final test plate mass is g.
A6L effect determination
(A3)
A6.1 Overview
Use the electrophoretic coating 1. Shaped test plate method to check the coating quality on the horizontal and vertical surfaces of the coated object and measure the electrophoretic effect of the coating. A6.2 Test instruments and materials
a) A set of electrophoretic coating equipment;
b) Test plate: Phosphate plate of the same material as the product on the production line: specification 70mm×150mmX0.8mm Fold into a right angle at 60mm from the lower end of the long side according to Figure A2. And process according to the specified phosphating process. Figure A24 Nesting evaluation
The lowest destruction voltage among the data obtained by repeating the operation more than twice is taken as the "destruction voltage" of the electrophoretic coating. The coating within 5mm of the submergence line is not the object of evaluation. A4 Determination of MEQ value of electrophoretic coating
A4.1 Overview
The electrophoretic coating with tetrahydrofuran added is titrated with potassium chloride ethanol standard solution. Calculate the moles of neutralizer consumed by 100g solid content of electrophoretic coating.
A4.2 Test instruments and materials
a) Beaker: 100ml.
b) Measuring cup: 50ml;
（）Precision balance: accurate to o.1mg:
d) 0.1mol/l potassium hydroxide ethanol standard solution;
//) THF (tetrahydrofuran);
//) Potentiometric titration device.
A4.3 Operation steps
a) Accurately weigh about 10g of electrophoresis tank liquid sample and put it into a 100ml beaker;
h) Add 50mL of THF solution to the above sample and connect it to the potentiometric titration device;
//) Titrate the obtained sample solution with 0.1mol/l potassium hydroxide ethanol standard solution, and the end point is determined by the potential curve;
Calculate the MEQ value according to formula (A2):
IB/T 10242-2001
Wherein: V is the number of milliliters of potassium hydroxide ethanol standard solution consumed in titration, ml; N is the concentration of potassium hydroxide ethanol standard solution, molL: G
The mass of the electrophoresis tank liquid sample, g;
The solid content of the electrophoresis tank liquid sample.
A5 Determination of heating loss
. (A2)
A5.1 Overview
The electrophoretic coating film is subjected to 105 (or 120°C to remove moisture and solvent, and then further heated to the drying temperature to make the coating film dry, and the mass of the coating film is measured. Calculate the heating loss. A5.2 Test instruments and materials
) One set of electrophoretic coating equipment:
h) Precision balance (accuracy 0.1mg); () Test plate: Phosphate plate of the same material as the product on the production line; Specification: 70mm×150mm×0.8mm; d) Electric heating blast drying oven (control error ±1℃C). A5.3 Operation steps
a) Use a balance to accurately weigh three test plates and record the weight W respectively. ; b) Carry out electrophoretic coating to achieve the standard film thickness, and let it stand for a long time after washing (more than 1h); c) After draining, The electrophoresis plate is baked at 120℃ for 1h or 105℃ for 3h, cooled in a dryer, and accurately weighed, Wl; d) The test plate is continued to be baked at the drying temperature required by the coating for 20min, taken out and placed in a dryer for cooling, and accurately weighed, and the mass W is recorded respectively.
A5.4 Calculation
Calculate the heating loss according to formula (A3) and take the average value. Heating loss-WW
武: w
Mass of the test plate before electrophoresis, g;
W.Mass of the test plate after baking at 120C or 105C, g; W
Coating solidification The final test plate mass is g.
A6L effect determination
(A3)
A6.1 Overview
Use the electrophoretic coating 1. Shaped test plate method to check the coating quality on the horizontal and vertical surfaces of the coated object and measure the electrophoretic effect of the coating. A6.2 Test instruments and materials
a) A set of electrophoretic coating equipment;
b) Test plate: Phosphate plate of the same material as the product on the production line: specification 70mm×150mmX0.8mm Fold into a right angle at 60mm from the lower end of the long side according to Figure A2. And process according to the specified phosphating process. Figure A2
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