Textile business negotiations and contracts tend to have a fabric weight required to sign, the
fabric weight per square meter of
fabric means no pulp dry weight, referred to the dry weight of the pulp-free cloth. It is an important technical indicator of grey fabrics, and it is also the main indicator for economic accounting of fabrics.
According to the size of the fabric sample and the specific conditions, it can be divided into two test methods: weighing method and calculation method. The calculation method needs to know the warp and weft yarn weaving shrinkage rate, and sometimes the warp and weft yarn shrinkage deviation is estimated to be large, resulting in a large error in the calculation result. Under normal circumstances, the company's laboratories and testing centers use a more accurate weighing method to test the greige fabric without pulp. Dry weight.
The instruments and tools required for testing grey fabrics without a dry weight by gravimetric method: balance (tray balance or electronic balance), induction cooker (usually 1500W), copper pot (or beaker), measuring cup, glass rod, concentrated sulfuric acid, iodine solution (to avoid Light preservation), oven, etc.
First, the preparation of dilute sulfuric acid solution:
Concentrate more than 95% concentrated sulfuric acid to a certain concentration of dilute sulfuric acid: (add 500ml of water to 100ml of concentrated sulfuric acid proportion) First in the beaker, inject a certain amount of water, measure the amount of concentrated sulfuric acid in the cup, left hand cup, right hand Take a glass rod and slowly pour the concentrated sulfuric acid into the beaker water while stirring. After cooling and cooling, pour the diluted sulfuric acid into a small glass container and seal it.
Note: The operator wears plastic gloves and masks due to volatilization and splashing during the process of dilution with concentrated sulfuric acid.
Second, the test steps are as follows:
1. Sample cloth: Use a disc sampler to take the sample of the test fabric (100 square centimeters in area) or cut the sample cloth into rectangles or squares with scissors, and measure the length and width of the sample cloth with a ruler to calculate the sample cloth. Area (cm 2 )
2, (according to the proportion of 10 grams of gray cloth corresponding to a minimum of 700ml water) measuring cup water required to take the test cloth into the copper pot (or beaker), and then placed on the induction cooker heating, until the water boils into the sample cloth to cook 10 Minutes, use glass to remove the sample cloth and wash it with water.
3, (according to the ratio of 10 grams of gray cloth corresponds to a minimum of 700ml of water) and then the amount of water required for the test cloth is weighed into a copper pan (or beaker) and placed on an induction cooker and heated to boiling, (corresponds to 14ml of 700ml of water Sulfuric acid proportion) Add appropriate amount of dilute sulfuric acid into the cup, place the sample cloth in boiling water, cover with lid and cook for 40 minutes. Use iodine solution to check if the desizing of the sample cloth is clean. If it is not removed, continue cooking. Until the slurry is clean, remove the sample cloth with a glass rod and rinse it with clean water.
4, open the oven, the sample cloth tiled in the oven partition on the bake 1.5-2.0 hours, the dried fabric with a balance weighing, calculate the gray fabric sample cloth dry weight.
5, due to loss of fiber in the desizing and cleaning process, use the loss factor to correct it, calculate the non-dry weight of the gray cloth:
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