Sample Preparation Method For Fiber Content Testing!

The fibers need to be identified after qualitative analysis.

That is to say

about

Samples,

It can be quantified.

According to GB/T 10629-2009 "preparation of laboratory samples and samples for textile chemical tests", it is stipulated that when the fiber content is prepared, for ordinary samples, the sample weight is about 1.0g 1.0g per sample, and the sample requires parallel test.

Textiles are usually divided into knitted fabrics and woven fabrics. Different methods of fabric preparation are different. The general sample and special sample preparation methods will be introduced below.

Sample preparation method for woven fabric samples

Generally speaking, the method of sample preparation for woven fabrics can be divided into two cases: after the sample is trimmed and the edges are not broken after trimming.

* samples containing wool must be broken after the edges.

The fabric is thicker and the reagent is difficult to soak through the sample to be dissolved.

Split sample: separate the warp and weft yarn after trimming or divide the yarn into several heaps according to the sample cycle.

Samples dissolved by formic acid zinc chloride method need to be disassembled.

1.2 no need to dismantle samples after trimming.

75% samples directly dissolved by sulfuric acid method, such as polyester fiber / cotton or linen, polyester fiber / viscose fiber, polyester fiber / Modal fiber and Lesel fiber blended products;

Two samples of direct dissolution of methyl formamide, such as viscose / spandex, cotton / spandex, modal fiber / spandex, polyester fiber / viscose / spandex, polyester fiber / cotton / spandex and other blended products;

* light and thin samples of mulberry silk / spandex, nylon / spandex blended, and so on, do not need to dismantle yarn after trimming, and are directly used for chemical dissolution.

Sample preparation method for knitted fabric samples

There are two kinds of knitting sample preparation methods: direct cutting two pieces and narrow strip cutting or splitting.

* samples of woven and lace samples, such as polyester fiber / spandex, nylon / spandex, polyester fiber / spandex, etc.

? light and thin samples such as T-shirts, netted spandex, etc., which do not contain wool or silk.

Fabrics with larger mesh size and smaller tightness.

All samples containing wool or silk, such as wool / polyester fiber, wool / acrylic fiber, etc.

? rough samples (such as samples of thread clothing), such as acrylic / cotton, nylon / viscose, etc.

* for samples containing spandex, such as cotton / spandex, viscose / spandex, modal fiber / spandex, it is possible to split and quantify the samples quantitatively and quantitatively.

Sample preparation method for special samples

In addition to the usual samples at work, there are still larger samples with larger loops or flowers. It is difficult to prepare samples. Next, we will introduce some sample preparation methods for routine inspection.

(1) there are two ways to deal with the larger woven samples. The conventional method is to prepare a complete cycle. As the sample is heavier, it needs to be divided into several groups and dissolve separately. In addition, there is a method of saving time and reagents, and 1/2 or 1/4 samples are disused for recycling.

(2) no cycle samples, different yarn components are different and can not be divided into yarn content results, should communicate with the relevant personnel qualitative results;

(3) samples of knitted fabrics with more organizational structure, such as knitted plain, rib or mesh, on a sample, can be randomly tested if it is the difference in organizational structure caused by weaving. However, for the lower end of the rib, one must pay attention to whether or not to weave other yarns. If there are other yarns, the main body should be noted.

(4) samples containing lace are treated in two cases:

When the cycle is small, it is desirable to take several cycle samples. When the cycle is large, it is desirable to have a cycle and mark a cycle. When it is cycled, it should pay attention to the characteristics of its circulation, for example, the flower shape will sometimes turn the direction, or there will be a different flower shape in the middle.

* when the sample is blended lace composite fabric, the first layer is

When another layer is knitted fabric or woven fabric, after qualitative analysis, if the lace fabric and another layer of fabric need to be dissolved, the lace should be torn off after finishing the cycle, otherwise the structure of the lace fabric will change, so that the circulation will be affected.

Then, another layer of fabric will be prepared. If there are more colloidal substances and significant effects on the results, it is necessary to communicate with the relevant personnel.

(5) when the sample is a general composite fabric, the upper layer is

In the middle, there are colloidal substances, and the lower layer is a single component of fabric. The removal of colloidal substances in the sample can be removed by chemical agents. When the content of colloidal substances in the sample is relatively small and the chemical reagent can not be removed, it can be dissolved directly. Finally, the content of colloidal substances is added to the residue. When the content of colloidal substances in the sample is relatively large and the chemical reagent can not be removed, it should be communicated with the relevant personnel.

(6) samples that need to be processed before:

* for the samples with bright powder, one piece should be cut first, enough to meet the sample demand, and the bright powder can be removed with acetone.

* a sample should be first cut for coated samples, sufficient to meet the needs of sample preparation, and coated with dichloromethane.

* for the blended sample with PU (composite layer fabric) and the sample component does not contain acrylic or spandex, PU/ composite layer fabric is removed by N, N- two methformamide, so as to prepare samples.

For cotton or linen and

Fiber blended samples need to be dissolved with sodium silicate (two sodium sulfite) to ensure the result of chemical dissolution.

* when samples are sutured or decorated with sequins, they can be removed manually. If the upper or lower seam is nylon, the suture and sequins can be removed from the sample with hydrochloric acid.

Sample preparation techniques

(1) for a sample of only one yarn, a cone can be used to select the yarn without separation and separation.

(2) for a circular sample, if the yarn is completely circulatory at the beginning and end, the intermediate process does not need to put too much energy into it.

(3) when the knitted fabric is knitted, it can observe the direction of its yarn or pick a yarn out of the cone, so as to avoid wasting time and save material.

Matters needing attention in sample preparation

Sample preparation is one of the important steps in the testing of fiber content. There are many details to be paid attention to.

Application of dismantling samples

Remove the yarn, remove the gauze and keep it clean and tidy, avoid losing the yarn and adding other samples to the yarn.

General sample should pay attention to the parallel sample weight when preparing samples, avoid sample overweight, consume sample time and dissolve reagent;

The samples to be disassembled must be broken up, for example, samples containing wool and coarser yarns;

* the samples before treatment should be noted except for colloidal substances / coating / composite layer except for sewing / sequins.

When the samples separated from the warp and weft are removed and dissolved, the samples should be inspected before they are disassembled.

When the samples are separated from each other at a time when the sample is separated from the warp and weft separates, the combustion method can be used to determine the unidirectional component and then the sample is prepared; or the unidirectional component is determined according to the yarn strength, the state of the yarn, and the electrostatic condition.

The sample should not be lost after dissolving.

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Counting after sample preparation: in order to improve the efficiency of weighing, special paper bags need to be marked with dates and page numbers.

After the sample is prepared, the ingredients should be identified to avoid writing or missing components. When the sample is placed into the weighing bottle, the number of the bottle body and the bottle cap should be taken into account.

When preparing the sample, if the matter is on the way, the sample should be placed in the weighing bottle or the sample should be handed over to another person to avoid the loss of the sample.