CN103994947A - Fiber specific gravity testing method - Google Patents

Abstract

The present invention discloses a fiber specific gravity testing method, which comprises: (1) placing a specific gravity bottle filled with distilled water into a beaker holding distilled water, wherein the plane of the distilled water in the beaker exceeds 0.1 of the specific gravity bottle; (2) maintaining a vacuum degree of 99.5% for 0.5 h; (3) maintaining a temperature of 20 DEG C for 24 h, and then weighing to obtain a mass W1; (4) taking 20 g of fibers to be determined, soaking the fibers for 20 min with anhydrous alcohol, removing the oil agent on the fiber surface, and drying for 1 h in a 50 DEG C environment; (5) weighing the fiber mass by using an electronic balance to obtain a mass W2; (6) placing all the dried and weighed fibers into the specific gravity bottle, adding distilled water until the specific gravity bottle is filled with the distilled water, placing the specific gravity bottle into the beaker holding distilled water, making the water plane exceed 0.5 mm the bottle opening of the specific gravity bottle, placing into a vacuum pumping device, controlling the vacuum degree of 99.7%, maintaining for 12 h, placing the specific gravity bottle into a sealed tank, and stabilizing the temperature to a room temperature of 20 DEG C; and (7) calculating the density.

Description

A kind of test method of fiber specific gravity

technical field

The invention relates to a method for rapidly testing fiber specific gravity.

Background technique

Density is an important parameter to characterize the physical properties of fibers. Its test method has always been concerned by scholars, and many explorations and researches have been carried out, and many test methods have been proposed. For example, the patent CN103091201 proposed a fiber quality analyzer. A fiber density measurement method for measuring pulp fiber particles; another example is the patent CN103323360, which proposes a method and device for measuring the density of a cellulose fiber blended product by using a density gradient method, and then calculating the fiber content. To sum up, there are currently three test methods recognized by the International Organization for Standardization and included in relevant standards: liquid displacement method, sink-float method, and density gradient column method. However, because the fiber aggregate contains a large amount of air, which interferes with the test results and greatly restricts its scope of use, there is still no effective and fast method for testing the specific gravity of fibers so far. In these three measurement methods, there are mainly the following problems: (1) During the experiment, the presence of air bubbles attached to the surface of the fiber and between the fiber monofilaments makes the data error larger, and how to remove the air bubbles is more troublesome. There are problems in this aspect in all test methods; (2) It is necessary to solve the influence of fiber surface tension effect and temperature change on the density measurement; (3) the solution required for the immersion solution in each method must be accurately selected, and the density accuracy of the immersion solution and The density range is required to be very large, and the resulting error is relatively large; (4) It is necessary to make a correct judgment on the fiber suspension state. In this process, the human error is very large, the experimental test data has a large error, and the accuracy is not high; (5) Configuration The process of the density gradient column is a very cumbersome process, because the top-to-bottom density of the configured density gradient column is not necessarily linear, the experimental process takes a long time, and there are artificial errors in the judgment of the fiber suspension state. Moreover, the sampling amount of the fiber pellets is only at the milligram level, which is too small. In addition, the defoaming method for fiber pellets is also defective, and the defoaming is not thorough.

Contents of the invention

Aiming at the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a test method with simple operation, high test efficiency and high test accuracy, which can be used for a large number of rapid determination of fiber specific gravity for the determination of various fiber densities.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a kind of test method of fiber specific gravity, comprises the steps:

1. Measurement of the mass W ₁ of a pycnometer filled with water only:

(1), put the 100ml pycnometer filled with distilled water into a 150ml beaker filled with distilled water, and keep the distilled water in the beaker submerged by 0.1-1cm of the pycnometer;

(2), then put the beaker together with the pycnometer into a vacuum device to evacuate, control the vacuum degree to 99.5% to 99.9%, and keep it for 0.5 to 3 hours;

(3) then take out the pycnometer and put it in a sealed tank, balance it for 24h under the condition of 20°C and weigh its quality, then get the quality _W of the pycnometer+water;

2. Measurement of fiber quality W ₂ :

(4) Take 20g of the fiber to be measured, soak the fiber with absolute alcohol or ether for 20-50 minutes, remove the oil on the surface of the fiber, and then dry it in an environment of 50°C-120°C for 1h-3h;

(5), after drying, weigh the quality of fiber with electronic balance, marked as W ₂ ;

3. Test of the quality W ₃ of the pycnometer filled with fiber and water:

(6), put all the fibers weighed after drying into the pycnometer, fill up with distilled water, put the pycnometer into a beaker filled with distilled water, and make the water surface 0.5mm over the mouth of the pycnometer, so that the specific gravity The bottle is immersed in water like a "submarine", put them together in a vacuum device, control the vacuum to 99.7%, keep it for 12 hours, and then put the pycnometer into a sealed tank to stabilize the temperature to room temperature 20 ℃;

(7), take by weighing the quality W ₃ of the pycnometer that fiber and water are housed, utilize Archimedes principle to obtain the density of fiber:

The above-mentioned test method of fiber specific gravity is characterized in that: the distilled water in the beaker in the step (1) has not passed the pycnometer for 0.5cm.

The above-mentioned test method of fiber specific gravity is characterized in that: in the step 2, the vacuum degree is set to 99.8% and kept for 2 hours.

The above-mentioned method for testing fiber specific gravity is characterized in that: in the step (4), the fiber is soaked in absolute alcohol or ether for 35 minutes, the drying temperature is 80° C., and the drying time is 2 hours.

The advantage of the test method of fiber specific gravity of the present invention is: the present invention uses pycnometer method to measure the density of fiber, has the characteristics of simple operation, high test efficiency, high test precision, can be used for the mensuration of a large number of rapid determination of various fiber densities. In the past, the water in the pycnometer bottle would continuously overflow during the vacuuming process, and it was necessary to continuously add water to the pycnometer bottle, and the newly added water would partially overflow due to the generation of air bubbles. Even if the water was continuously added, it was difficult to accurately measure the specific gravity of the fiber. The present invention directly puts the pycnometer into a beaker filled with distilled water, and keeps the distilled water in the beaker submerged by about 0.1-1cm of the pycnometer, then puts the beaker together with the pycnometer into a vacuuming device to evacuate. The effect bubbles will continuously overflow, because the distilled water in the beaker has not passed the pycnometer, so water will continue to replenish when the bubbles continue to overflow. During the vacuuming process, the vacuum degree should be kept above 99.5%, and not less than 0.5 hours. The higher the vacuum degree, the better, and the longer the time, the better. Finally, remove the negative pressure and take out the pycnometer, put it into a sealed tank, balance it at 20°C for 24 hours, weigh it, and calculate the specific gravity of the fiber.

Detailed ways

Below in conjunction with specific embodiment the present invention is described in further detail;

Example 1:

A method for testing fiber specific gravity, comprising the steps:

1. Measurement of the mass W ₁ of a pycnometer filled with water only:

(1), put the 100ml pycnometer filled with distilled water into the 150ml beaker filled with distilled water, and keep the distilled water in the beaker covered by 0.1cm of the pycnometer;

(2), then put the beaker together with the pycnometer into the vacuum device to evacuate, control the vacuum to 99.5%, and keep it for 3h:

(3) then take out the pycnometer and put it in a sealed tank, balance it for 24h under the condition of 20°C and weigh its quality, then get the quality _W of the pycnometer+water;

2. Measurement of fiber quality W ₂ :

(4) Take 20g of the fiber to be measured, soak the fiber with absolute alcohol or ether for 20min, remove the oil on the surface of the fiber, and then dry it at 120°C for 1h;

(5), after drying, weigh the quality of fiber with electronic balance, marked as W ₂ ;

3. Test of the quality W ₃ of the pycnometer filled with fiber and water:

(6), put all the fibers weighed after drying into the pycnometer, fill up with distilled water, put the pycnometer into a beaker filled with distilled water, and make the water surface 0.5mm over the mouth of the pycnometer, so that the specific gravity The bottle is immersed in water like a "submarine", put them together in a vacuum device, control the vacuum to 99.7%, keep it for 12 hours, and then put the pycnometer into a sealed tank to stabilize the temperature to room temperature 20 ℃;

(7), take by weighing the quality W ₃ of the pycnometer that fiber and water are housed, utilize Archimedes principle to obtain the density of fiber:

Although the fiber will swell to varying degrees due to moisture absorption in water, since the defoaming and water replenishment in this method are a continuous process, the influence of air bubbles on the experimental results is significantly reduced, and it has high precision, good reproducibility and stability. Good advantage, even if the specific gravity of cotton fiber is tested, the result is basically stable between 1.535 and 1.550, which is consistent with the recognized data at home and abroad. Of course, using this method to test the specific gravity of polypropylene, polyester, acrylic, nylon and other fibers with less hygroscopicity is faster, within 3 hours; the data is more stable, with an average difference of about 0.003.

Example 2:

A method for testing fiber specific gravity, comprising the steps:

1. Measurement of the mass W ₁ of a pycnometer filled with water only:

(1), put the 100ml pycnometer filled with distilled water into a 150ml beaker filled with distilled water, and keep the distilled water in the beaker covered by 0.5cm of the pycnometer;

(2), then put the beaker together with the pycnometer into a vacuum device to evacuate, control the vacuum degree to 99.8%, and keep it for 2h;

(3) then take out the pycnometer and put it in a sealed tank, balance it for 24h under the condition of 20°C and weigh its quality, then get the quality _W of the pycnometer+water;

2. Measurement of fiber quality W ₂ :

(4) Take 20g of the fiber to be measured, soak the fiber with absolute alcohol or ether for 35 minutes, remove the oil on the surface of the fiber, and then dry it at 80°C for 2 hours;

(5), after drying, weigh the quality of fiber with electronic balance, marked as W ₂ ;

3. Test of the quality W ₃ of the pycnometer filled with fiber and water:

(6), put all the fibers weighed after drying into the pycnometer, fill up with distilled water, put the pycnometer into a beaker filled with distilled water, and make the water surface 0.5mm over the mouth of the pycnometer, so that the specific gravity The bottle is immersed in water like a "submarine", put them together in a vacuum device, control the vacuum to 99.7%, keep it for 12 hours, and then put the pycnometer into a sealed tank to stabilize the temperature to room temperature 20 ℃;

(7), take by weighing the quality W ₃ of the pycnometer that fiber and water are housed, utilize Archimedes principle to obtain the density of fiber:

Example 3:

A method for testing fiber specific gravity, comprising the steps:

1. Measurement of the mass W ₁ of a pycnometer filled with water only:

(1), put the 100ml pycnometer filled with distilled water into the 150ml beaker filled with distilled water, and keep the distilled water in the beaker covered by 0.1cm of the pycnometer;

(2), then put the beaker together with the pycnometer into a vacuum device to evacuate, control the vacuum to 99.9%, and keep it for 1h:

(3) then take out the pycnometer and put it in a sealed tank, balance it for 24h under the condition of 20°C and weigh its quality, then get the quality _W of the pycnometer+water;

2. Measurement of fiber quality W ₂ :

(4) Take 20g of the fiber to be measured, soak the fiber with absolute alcohol or ether for 50min, remove the oil on the surface of the fiber, and then dry it at 50°C for 3h;

(5), after drying, weigh the quality of fiber with electronic balance, marked as W ₂ ;

3. Test of the quality W ₃ of the pycnometer filled with fiber and water:

(6), put all the fibers weighed after drying into the pycnometer, fill up with distilled water, put the pycnometer into a beaker filled with distilled water, and make the water surface 0.5mm over the mouth of the pycnometer, so that the specific gravity The bottle is immersed in water like a "submarine", put them together in a vacuum device, control the vacuum to 99.7%, keep it for 12 hours, and then put the pycnometer into a sealed tank to stabilize the temperature to room temperature 20 ℃;

(7), take by weighing the quality W ₃ of the pycnometer that fiber and water are housed, utilize Archimedes principle to obtain the density of fiber:

Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention shall all belong to protection scope of the present invention.

Claims (4)

1. a method of testing for fiber proportion, is characterized in that, comprises the steps:

One, the pycnometer quality W of water is only housed ₁measurement:

(1), the 100ml pycnometer of filling distilled water is put into the 150ml beaker that fills distilled water, and keep the distilled water in beaker not have pycnometer 0.1～1cm;

(2), then beaker is put into vacuum extractor together with pycnometer and vacuumizes, control vacuum tightness and reach 99.5%～99.9%, and keep 0.5～3h;

(3) then pycnometer is taken out and puts into sealable tank as for claiming its quality after balance 24h under 20 DEG C of conditions, obtain the quality W of pycnometer+water ₁;

Two, fiber quality W ₂measurement:

(4), get fiber 20g to be determined, soak fiber 20min～50min with anhydrous alcohol or ether, remove the finish of fiber surface, then in 50 DEG C～120 DEG C environment drying time at 1h～3h;

(5), dry after by the quality of electronic balance weighing fiber, be labeled as W ₂;

Three, the pycnometer quality W of fiber and water is housed ₃test:

(6), after dry, claimed the fiber of quality all to put in pycnometer, fill it up with distilled water, pycnometer is put into the beaker that fills distilled water, and make the water surface not have pycnometer bottleneck 0.5mm, and make pycnometer be similar to " submarine " and be equally immersed in water, it is put into vacuum extractor together, control vacuum tightness and reach 99.7%, keep 12 hours, then pycnometer is put into sealable tank, make its temperature stabilization to 20 DEG C of room temperatures;

(7), take the pycnometer quality W that fiber and water are housed ₃, utilize Archimedes principle to obtain the density of fiber:

2. the method for testing of fiber proportion according to claim 1, is characterized in that: the distilled water in described step (1) in beaker did not have pycnometer 0.5cm.

3. the method for testing of fiber proportion according to claim 1, is characterized in that: in described step 2, vacuum tightness is set to 99.8%, keeps 2 hours.

4. the method for testing of fiber proportion according to claim 1, is characterized in that: in described step (4), soaking the fiber time with anhydrous alcohol or ether is 35min, and bake out temperature is 80 DEG C, and drying time is 2h.