QB/T 2223-1996 Test method for acrylic resin emulsion for leather making
Some standard content:
QB/T2223—1996
This standard is a revised version of ZBG31002-1988 "Test Methods for Acrylic Resin Emulsions for Leather Making". According to the relevant national standard compilation regulations, the "Sampling" chapter in the original standard has been cancelled, and the contents in the original standard that are not suitable for technical and economic development have been revised. This standard will replace ZBG31002--1988 from the date of entry into force. This standard is proposed by the Quality Standards Department of the China Light Industry Federation. This standard is under the jurisdiction of the National Fur Leather Standardization Center. The drafting units of this standard are: China Leather Industry Research Institute, Beijing Leather Industry Research Institute, Beijing Leather Company Chemical Plant. The main drafters of this standard are: Yang Jianjun, Wang Shuping, Chen Jihe. 143
1 Scope
Light Industry Industry Standards of the People's Republic of China
Test Methods for Acrylic Resin Emulsions for Leather Making This standard specifies the test methods for acrylic resin emulsions for leather making. QB/T2223---1996
This standard applies to anionic emulsions made by emulsion polymerization based on acrylic ester monomers. The main purpose of acrylic resin emulsions is to make finishing agents or fillers for various upper leathers, clothing leathers, glove leathers, etc. 2 General test rules
2.1 When testing, the sample must be shaken before taking the sample. 2.2 For each test item, two samples should be taken at the same time (except for each test item of acrylic resin film) for parallel testing. 2.3 When testing acrylic resin film:
a) When measuring tensile strength, elongation at break and permanent deformation, the result will be invalid if the breaking point is outside the marking line; b) Each group of samples shall not be less than 5, and the number of samples shall not be less than 60% of the original samples in calculation to obtain the arithmetic mean; c) The error of the calculated result shall not exceed ±10%, otherwise the sample shall be re-sampled and re-tested. 2.4 The analysis results of each test shall be retained to one decimal place. 2.5 When the error of the parallel test results is within the allowable error range, take the arithmetic mean as the test result. If it exceeds the range, take another sample and retest.
3 Test method
3.1 Appearance
Observe the emulsion for impurities and coagulants by visual inspection. 3.2 Determination of total solids
3.2.1 Instrument
a) Ground-mouth flat-bottom weighing bottle with cover: 40mm×25mm; b) Electric constant temperature oven: 0~200℃;
c) Analytical balance: sensitivity 0.0001g
d) Dryer.
3.2.2 Steps
Weigh 1-2g of sample (accurate to 0.0002g) into a weighing bottle that has been dried to constant weight, place it in a (105±2)℃ constant temperature oven to dry for 4h, take out the weighing bottle, cover it, cool it in a desiccator for 30min and weigh it, dry it again for 30min and cool it, weigh it until constant weight. 3.2.3 Calculation
Where: X total solid content, %,
A.…Mass of empty weighing bottle.;
B—Mass of weighing bottle and dried material, g.
Approved by China Light Industry Association on June 5, 1996
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Implemented on March 1, 1997
Mass of sample, g.
3.2.4 Error
QB/T 2223—1996
The error of two parallel tests is not more than 0.3%. 3.3 Determination of pH value
3.3.1 Instrument
The pH meter has a glass electrode, a measuring range of pH 0~14, and a scale of 0.1 pH value. 3.3.2 Steps
Measure 30mL of the sample in a 50mL beaker and measure it on the pH meter. 3.3.3 Error
The error of two parallel tests is not more than 0.1. 3.4 Determination of bromine value
3.4.1 Principle
This method is based on the determination of double bonds in monomers by potassium bromate-potassium bromide. The bromine precipitated by potassium bromate in the following reaction can quickly react with the position of the double bond, and the excess bromine reacts with potassium iodide, and finally the precipitated iodine is titrated with sodium thiosulfate. KBrO:+5KBr-→+6HCl→3Br2+6KCl+3H2OCH2=CH · COOR+Br2 —
Br2+2KI—→2KBr+12
CH,Br · CHBr · COOR
I2 +2Na2S,O, ---Na2O,Os+2Nal3.4.2 Apparatus
a) Ground-mouth flask with stopper: 250mL,
b) Pipette: 25ml.
3.4.3 Reagents
a) Preparation of 0.01mol/L potassium bromate-potassium bromide solution: weigh 12.5g potassium bromide and 1.5g potassium bromate into a 200mL beaker, add appropriate amount of distilled water to dissolve and transfer to a 1000mL volumetric flask, dilute to the scale with distilled water, and shake well; b) Sodium dodecyl sulfate: 5%;
c) Potassium iodide solution: 10%;
d) Hydrochloric acid solution: 1:1;
e) Starch solution: 1% (newly prepared or add a little mercuric iodide after preparation) f) Sodium thiosulfate: Preparation method of 0.05 mol/L standard solution: weigh about 25 g of sodium thiosulfate (NazS,O;·5H,0) on a coarse balance and place it in a 500 mL beaker, add 400 ml of distilled water that has just been boiled and cooled to room temperature, add 0.05 g of sodium carbonate (to prevent solution decomposition) and 0.01 g of mercuric iodide (to prevent mold), then transfer to a 1000 mL volumetric flask, and dilute to the scale with freshly boiled distilled water, sow the hook, let it stand overnight or longer (8~~14 days), and then calibrate and apply.
Calibration method: Accurately weigh 0.10-0.12g of potassium dichromate (K,Cr.0,) dried at 105℃, add 30ml of distilled water to dissolve it, add 5ml of concentrated hydrochloric acid and 10ml of 15% potassium iodide solution, mix thoroughly and dilute to 200ml, titrate with the prepared sodium thiosulfate working solution until it turns light yellow-green (straw color), then add 5ml of 0.05% starch solution, and continue titrating until the light blue color disappears and turns into green of trivalent chromium ions.
Concentration calculation:
VX0.04904
Where: ℃ -
concentration of sodium thiosulfate solution, mol /L, mass of potassium dichromate, nom;
0. 049 04 -
QB/T2223—1996
volume of sodium thiosulfate solution consumed, mL; molar mass of potassium dichromate.
3.4.4 Steps
Weigh 0.4~~0.6g of sample (accurate to 0.0002g) into a 250mL stoppered ground-mouth flask filled with 60mL of 5% sodium dodecyl sulfate solution, shake well, add 25mL of 0.01mol/L potassium bromate-potassium bromide solution with a pipette, slowly add 10ml of 1:1 hydrochloric acid solution along the bottle wall, plug the bottle tightly, shake well, add potassium iodide solution to seal. Place in a dark place for 30min, add 10mL of 10% potassium iodide solution, immediately titrate with 0.05mol/1 sodium thiosulfate solution, add 2mL of starch indicator when it is close to the end point, and then continue to titrate until the blue color disappears completely as the end point. At the same time, do a blank test.
3.4.5 Calculation
Where: X--
Br value, %;
x=(VV)xx79.9×100
1000xW
V. —-Blank test consumption of sodium thiosulfate standard solution, mLV—-Sample consumption of sodium thiosulfate standard solution, mL; c-.…-Concentration of sodium thiosulfate standard solution, mol/LW—Sample mass, g
79.9—Number of grams of bromine per mole.
3.4.6 Error
The error of the results of two parallel tests is not greater than 0.1. 3.5 Determination of thermal stability
3.5.1 Principle
This method is to heat the emulsion at a certain temperature for a certain period of time, and then the thermal stability is expressed by the increase of the emulsion particles. 3.5.2 Instruments
a) Electric constant temperature drying oven: 0~200℃; b) Electric centrifuge: 3500r/min;
c) Wide-mouth bottle: 100mL;
d) Glass centrifuge tube: 10mL.
3.5.3 Steps
(3)
Take 50mL of the sample and put it in a wide-mouth bottle, seal the lid tightly, and place it in a constant temperature drying oven adjusted to (60±1)℃ for 120 hours. Take it out, cool it to room temperature, and observe. There are two situations as follows: a) There is obvious precipitation in the wide-mouth bottle, which means it has no thermal stability; b) There is no obvious precipitation in the wide-mouth bottle. Take 10mL of the heated sample and the original sample respectively, and centrifuge at a speed of 3500r/min for 10 minutes. Stop the machine and take it out. Compare the precipitation of the two samples. The one with obvious increase is inert to heat stability, and the one with no obvious increase is thermally stable. 3.6 Determination of chemical stability
3.6.1 Reagents
a) 5% ammonium hydroxide solution;
b) 5% formaldehyde solution;
c) 3% sodium sulfate solution.
3.6.2 Steps
3.6.2.1 Stability of 5% ammonium hydroxide solution Take 10ml of sample in a 50mL beaker, add 2mL of 5% ammonium hydroxide solution, stir evenly, leave for 10min, observe, if there is coagulation phenomenon, it is demulsification, if there is no coagulation phenomenon, it is not demulsification. 146
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3.6.2.2 Stability of 5% formaldehyde solution
QB/T 2223—19 ...
3.6.2.3 Stability of 3% sodium sulfate solution
Take 10mL of sample in a 50mL beaker, add 2mL of 3% sodium sulfate solution, stir evenly, leave for 10min, observe, if there is condensation phenomenon, it is demulsification, if there is no condensation phenomenon, it is not demulsification. 3.7 Membrane preparation
3.7.1 Equipment
a) Adjustable water platform (terrazzo or glass plate): area 600mm×400mm, b) Level ruler;
c) Membrane plate (glass plate sprayed with polytetrafluoroethylene film): area 240mm×130mm; d) Glass rod;
e) Infrared lamp: 250W;
f) Single voltage regulator: capacity 1kVA;
g) Thermometer: graduation value is 1℃.
3.7.2 Steps
Use a level ruler to adjust the adjustable water platform to a horizontal level, and place the cleaned membrane on the water platform. After diluting the acrylic resin emulsion to a solid content of about 24%, weigh 80-85g, pour it on the membrane, and use a glass rod to push the emulsion to the edge of the membrane to make it evenly distributed. Use a voltage regulator to adjust the infrared lamp to make the film drying temperature about 25℃. When the emulsion surface forms a film, gradually increase the temperature to 40-45℃ until the film is transparent and continue to dry for 2h. After the membrane is cooled, apply a little talcum powder on the surface of the film, gently remove the film and set it aside. 3.7.3 Film requirements
3.7.3.1 The film should be evenly hooked and flat, and there should be no defects such as bubbles, ripples, wrinkles, cracks, damage, etc. 3.7.3.2 Film thickness: 0.3~0.6mm. 3.7.4 Sample pretreatment
Before the test, the sample should be placed at a temperature of (20 ± 2) °C and a relative humidity of 60% to 70% for 4 hours. The test is required to be carried out under these conditions. 3.8 Determination of film tensile strength
3.8.1 Principle
The tensile strength is the load per unit cross-sectional area when the sample is broken on the tensile machine, expressed in Newton/mm2. 3.8.2 Equipment
a) Dumbbell-shaped cutter (as shown in Figures 1 and 2): The size must meet the requirements of Table 1; b) 500N tensile machine: The speed must be uniform and can be adjusted as needed; c) Thickness gauge
The measuring range is 0~10mm, the graduation value is 0.01mm; the measuring surface diameter is (10 ± 0.1) mm, and the total pressure of the pressure angle is (100±5)g. H
Figure 1 Dumbbell-shaped cutter
Figure 2 View of the cutting edge of the cutter
3.8.3 Steps
Basic dimensions
QB/T 2223—1996
Table 1 Dimensions of dumbbell-shaped cutter
Allowable deviation
Basic dimensions
Allowable deviation
3.8.3.1 Take 5 specimens from the finished film in turn using a dumbbell-shaped cutter and number them. Print parallel markings with a distance of 15 mm in the middle of the specimen. Each marking should be equidistant from the center of the specimen.
3.8.3.2 Use a thickness gauge to measure the thickness within the markings of the specimen. There should be no less than 3 measuring points and take the average value. 3.8.3.3 Clamp the sample between the upper and lower clamps of the tensile machine vertically, and the stretching speed is (500 ± 50) mm/min. Start the switch and record the load value at break.
3.8.4 Calculate
Where: X-
The tensile strength of the sample, N/mm:
The load value when the sample is pulled apart, N,
S-—The cross-sectional area of the sample at the break, mm2. 3.9 Determination of the elongation at break of the film
3.9.1 Principle
The elongation at break is the ratio of the elongation of the sample when it is pulled apart on the tensile machine to the original length, expressed as a percentage. 3.9.2 The elongation at break of the sample
is determined in the process of determining the tensile strength, and no additional sampling is required. 3.9.3 Procedure
(4)
During the process of measuring tensile strength, the distance between the two markings is measured at any time when the sample is stretched. When the sample breaks, the distance between the two markings is the length of the sample when it breaks.
3.9.4 Calculation
Where: X—elongation at break,%;
L. Distance between markings when the sample breaks, mm;
Distance between markings of the original sample, mm.
3.10 Determination of permanent deformation of film
3.10.1 Principle
The remaining deformation after the sample is stretched to break and then allowed to recover in a free state for a certain period of time. 3.10.2 Sample
The permanent deformation is determined during the process of measuring tensile strength, and no additional sampling is required. 3.10.3 Steps
During the process of measuring tensile strength, record the length at break, remove the broken sample and place it for 3 minutes, match the broken part of the sample, and measure the distance between the markings with a measuring tool with an accuracy of 0.5 mm. 3.10.4 Calculation
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Where: Y_
Permanent deformation, %;wwW.bzxz.Net
QB/T 2223--1996
L,---Distance between markings when the sample breaks, mm; L2--Distance between markings after the sample breaks and is placed for 3 minutes, mm; L
--Distance between markings of the original sample, mm.
3.11 Determination of water absorption of film
3.11.1 Principle
The ratio of the water absorption of the sample after immersion in water for 2 hours to the original mass of the sample is expressed as a percentage (i.e. water absorption). 3.11.2 Instruments
a) Analytical balance: sensitivity 0.001g;
b) Cutting knife: (40±0.01)mm×(40±0.01)mm;c) Culture blood: diameter 120~140mm;
d) Glass ball: diameter 3~5mm.
3.11.3 Steps
Use the cutting knife to cut 3 samples, number them, and weigh the sample mass (accurate to 0.001g). Place the sample in the culture III filled with distilled water (put the glass ball in the culture blood). After 2 hours at room temperature, take out the sample, wipe off the surface moisture with filter paper, and weigh it immediately (accurate to 0.001g).
3.11.4 Calculation
W——mass of the sample after absorbing water, g;
W——mass of the sample, g.
Note: Each group of samples shall not be less than 3, and the results shall not be less than 2 during calculation. The error shall not exceed 10%, otherwise re-sample and re-test. 3.12 Determination of film brittle temperature
3.12.1 Principle
The brittle temperature is the highest temperature at which the sample undergoes brittle fracture when subjected to a certain impact force at low temperature. 3.12.2 Equipment
a) Cutting knife: (100±0.1)mmX(10±0.1)mm; b) Low temperature box: 0~～40℃,
c) Impact instrument
Circular impact hammer: diameter is (30±1)mm, mass is (150±1)g. The distance between the impact hammer and the sample is (200±5)mm, and the bottom of the impact hammer is parallel to the bottom of the instrument; d) Low temperature thermometer: the graduation value is 1C.
3.12.3 Steps
3.12.3.1 Place the impact instrument in the low temperature box, lower the temperature to the predetermined temperature and keep it constant for 30 minutes. (7))
3.12.3.2 Take 5 specimens with a cutter, support the specimens with tracing paper strips to form a circular sleeve, fix them on the clamping plate of the impact instrument, and quickly place them on the plane of the impact instrument at a constant temperature, and freeze them for 10 minutes. 3.12.3.3 Start the impact instrument and let the impact hammer impact the circular part of the specimen in a free fall manner. 3.12.3.4 Measure 5 specimens at the same temperature, and if 3 or more of them are brittle, this temperature is the brittle temperature of the specimen. Note
1 Use a new specimen for each impact, and do not reuse the specimen. 2 The test temperature drop interval for each group of specimens is (5±1)℃. 149
Test report
a) Indicate whether the test is carried out in accordance with this standard;
QB/T2223
b) Sample number, name, brand, test item, manufacturer; c) Whether the sample is pre-treated and its conditions;
d) Test conditions;
e) Test results;
f) Test personnel and date.
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