Performance and test methods of printing and dyeing auxiliaries
The performance of printing and dyeing auxiliaries is not only crucial to auxiliary manufacturers, but also attracts more and more attention from printing and dyeing enterprises. The previous friends also mentioned this issue. Through this topic, we will summarize some commonly used performance indicators and test methods of printing and dyeing auxiliaries for your reference. I hope that friends in the chemical industry will actively participate.
Solid content:
The solid content can generally be measured by the drying method. Weigh an additive sample of a certain weight (w0) and dry it in an oven at 105 degrees until the weight no longer changes. Change, the weight at this time is w1, then the solid content is w1 divided by w0.
The drying method is applicable to most printing and dyeing auxiliaries, but there are some exceptions.
Identification of ionicity
Add 5 mL of methylene blue reagent into a stoppered test tube (weigh 0.03g of methylene blue, stir with 12g of concentrated sulfuric acid and 50g of anhydrous sodium sulfate, and dilute to 1L with distilled water) and 5 mL Chloroform. Then add the sample to be tested dropwise, one drop at a time, and shake vigorously up and down until the upper and lower parts have the same color. Continue to add 2 mL of the sample to be tested, shake, and then let it stand until it stratifies.
If the chloroform layer is dark in color and the water layer is colorless, the sample being tested is anionic.
If the chloroform layer is colorless and the water layer is dark, the sample being tested is cationic.
This method is more obvious for surfactant samples, such as lotions and scouring agents. It requires some experience for emulsion samples.
Determination of cloud point
Prepare the sample into a 1% solution with distilled water in a beaker, then slowly heat it, stir while heating, and measure the temperature with a thermometer until the solution changes from clear to turbid. Read the temperature value. Then cool the sample solution naturally while stirring, and read the temperature value when the solution changes from turbid to clear. Repeat several times and take the average value as the cloud point temperature.
Cloud point is a characteristic indicator of non-ionic surfactants and is not applicable to anionic or cationic surfactants and emulsion samples.
Determination of Foaming
In a stoppered graduated test tube (it is best to choose a test tube of 20mL or more), add a certain amount (such as 10mL) of the sample to be tested, and cover the stopper (to ensure it will not leak) liquid), shake it up and down 20 times, and the height of the foam in the test tube is used as the standard for foaming properties. The higher the foam, the better the foaming properties.
Determination of defoaming performance
Take two stoppered test tubes of the same size (preferably more than 20mL), add the same amount of the tested sample (for example, 10mL), and shake vigorously up and down 20 times. The time required for complete destruction is the defoaming time. The shorter the defoaming time, the faster the defoaming and the better the defoaming performance.
Determination of anti-foam performance
Take two stoppered test tubes of the same size (preferably more than 20mL), add the same amount of the tested sample (such as 10mL), shake it up and down 20 times, and read the foam The height reached and less foam indicates good anti-foaming performance.
Determination of acid resistance
Take several beakers of the same size, add the same amount (for example, 100 grams) of the tested sample, and then add glacial acetic acid to the beakers in increments of 5 grams and stir. Evenly, observe whether there is turbidity or stratification. The amount of acetic acid added in the beaker where turbidity or stratification occurs is the acid-resistant amount. In order to express the acid resistance more accurately, the added amount that causes turbidity or separation can be used as the intermediate value, the increased amount can be reduced, and the previous operation can be repeated.
Determination of Alkali Resistance
Take several beakers of the same size, add the same amount (for example, 100 grams) of the tested sample, and then add caustic soda (or Soda ash) solution and stir evenly, observe whether there is turbidity or stratification. The amount of caustic soda (or soda ash) solution in the beaker where turbidity or stratification occurs is the alkali resistance amount. Similarly, you can use the amount of addition that causes turbidity or stratification as the intermediate value, reduce the amount of increase, and repeat the previous operation to obtain a more accurate alkali resistance.
Determination of electrolyte resistance performance
Take several beakers of the same size, add the same amount (for example, 100 grams) of the tested sample, and then add the electrolyte solution to the beakers in increments of 5 grams. Stir evenly and observe whether there is turbidity or stratification. The amount of electrolyte solution in the beaker where turbidity or stratification occurs is the electrolyte resistant mass. Taking the amount of addition that causes turbidity or stratification as the intermediate value, reducing the amount of increase and repeating the previous operation can obtain a more accurate amount of electrolyte resistance.
Electrolytes generally use magnesium chloride, sodium chloride, etc., which can also be selected according to actual needs.
Measurement of hard water resistance
Hard water resistance is similar to electrolyte resistance. The result of using calcium chloride and magnesium chloride as electrolyte is hard water resistance. For ease of use, the concentration of the electrolyte-resistant solution can be converted into water hardness.
Permeability test
Prepare the test solution according to a certain concentration of the sample to be tested. Place the standard canvas piece horizontally on the surface of the test solution. The time from when the canvas piece starts to sink to the time it sinks to the bottom of the cup is expressed. The permeability of the sample being tested.
Alkali resistance permeability test
Add a certain amount of caustic soda to the test solution for testing permeability above, and the test result is the alkali resistance permeability of the sample being tested.
Wettability test
The fabric is made of the tested sampleTreat it as liquid, then dry it, lay it flat on a table, use a clean dropper to absorb distilled water, and drop a drop on the surface of the fabric. The time from when the water droplet falls on the surface of the fabric to when the water droplet is completely spread on the surface of the fabric represents the sample being tested. wetting properties.
Dispersion test
Mix a certain amount of sodium oleate solution with the test sample solution of different concentrations, and add a certain amount of calcium chloride solution (excessive relative to sodium oleate) under stirring. The quality of the dispersion can be judged based on the amount of calcium soap flocculant floating out of the solution or the amount of calcium soap dispersed in the water.
Washing power test
Mix the tested sample and the comparison sample into a solution of a certain concentration, and wash the standard dirty cloth under specified conditions. Visually observe the color depth of the washed and dried standard dirty cloth to evaluate the relative cleaning power of the tested sample.
For printing and dyeing enterprises, there is no need to specially make or buy standard stained cloth. They can use the production water from the relevant processes in actual production to soak the fabric and use it as a standard stained cloth.
Calcium ion complexing ability test
Take a certain amount of the sample to be tested (if the content is relatively high, you can dilute it a certain number first), use sodium oxalate as the indicator, and use pre-prepared calcium (such as chlorine Calcium oxide) standard solution is titrated until the solution appears turbid or white precipitate is the end point. The amount of calcium ions consumed divided by the weight of the tested sample is the ability of the tested sample to complex calcium ions per unit weight.
Iron ion complexing ability test
Take a certain amount of the sample to be tested (if the content is relatively high, the sample can be diluted a certain multiple), and adjust the pH value to 10– with 30% sodium hydroxide solution. –12, and then titrate with ferric ammonium sulfate standard solution until the turbidity is no longer dissolved or the color changes, which is the end point. The amount of consumed iron ions divided by the weight of the tested sample is the ability of the tested sample to complex iron ions per unit weight.
Sodium oleate is the sodium salt of oleic acid, which is an unsaturated fatty acid with sixteen carbons. The reason why sodium oleate is used is that sodium oleate can react with calcium ions to form flocculent precipitates that are insoluble in water. These precipitates can be partially dissolved in water under the dispersion of additives. The stronger the dispersion ability, the greater the dissolved amount. The bigger. AAKY,7II56U65
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