JPS5950788B2 - Mercerizing method for knitted fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for mercerizing knitted fabrics.

It is already known to mercerize cellulose fibers.

Mercerizing involves holding cellulose fibers under tension, impregnating them with a concentrated aqueous solution of caustic alkali and keeping them moist for a while, then washing them with warm water, neutralizing them with acid, and then washing them with water. done in order.

In principle, mercerization processing involves bringing cellulose fibers into contact with an aqueous caustic solution, while cellulose fibers originally had the crystal structure of cellulose I.
It is explained that the process involves causing a chemical reaction to produce alkali cellulose I and alkali cellulose (2), and then washing with water to remove the caustic alkali and converting it into cellulose (2), which is the crystalline structure of water cellulose.

For this reason, cellulose fibers after mercerization have improved gloss, dyeability, morphological stability, strength, and other properties, resulting in superior quality fibers.

As mentioned above, the purpose of mercerization processing is to impregnate cellulose fibers with an aqueous solution of caustic alkali and cause a chemical reaction to change the crystal structure, so the actual operation is performed in an aqueous solution of caustic alkaline. It was also carried out in a wet state.

Even if the aqueous caustic alkali solution was sometimes squeezed out by a mangle or the like during the mercerization process, the fibers were always kept in a wet state containing a water content of 60% by weight or more during the mercerization process.

On the other hand, mercerization was usually carried out on cellulose fibers in the form of yarns, but also in the form of woven or knitted fabrics.

In addition, once the yarn is mercerized,
It is also known to weave or knit this yarn into a woven or knitted fabric, which is then subjected to pagination and mercerization.

In any case, as mentioned above, the purpose of mercerization processing is to cause a change in the crystal structure through a chemical reaction, so it requires the presence of a large amount of moisture. There was no processing involved.

In mercerization processing, it is necessary to maintain the fibers in a tensioned state, so after mercerizing cellulose fibers in the form of thread, this thread is woven or knitted to form a woven or knitted fabric, and then the page and this When mercerizing woven or knitted fabrics, it was necessary to maintain tension by pulling the woven fabrics and knitted fabrics horizontally and vertically.

In the case of a woven fabric, it is possible to clip both sides of the fabric and pull it horizontally and vertically to maintain it in tension, but in the case of a knitted fabric, pulling it too hard will distort the stitch structure, so it cannot be kept in a tension state. Difficult to maintain.

Furthermore, when a knitted fabric is mercerized by pinning both side edges with pins, the stitches on both side edges become dense, causing unevenness in the width direction, making it impossible to make the entire fabric uniform.

For this reason, conventionally, even if the knitted fabric is subjected to mercerization processing, coarseness and coarseness of coarseness and density occur, and it has not been possible to improve gloss, strength, dyeability, etc. as with woven fabrics.

This inventor proposed that when mercerizing a knitted fabric, the fabric is not kept under tension in a caustic aqueous solution, but is impregnated with a caustic alkaline aqueous solution so that it can freely contract, and then the knitted fabric is pulled out of the caustic alkaline aqueous solution. We attempted to mercerize the knitted fabric by stretching it in the length and width directions using a tenter while drying the fabric to a certain degree and keeping it in a low-moisture state, and keeping it in a tensioned state for a while.

In other words, we attempted to dry mercerize the knitted fabric.

As a result, it has been found that by doing so, the knitted fabric can be strongly stretched in the width direction without changing the shape of the stitches, and mercerization can be uniformly performed in the width direction as well.

This invention was made based on such knowledge.

This invention involves impregnating a thread containing cellulose fibers with caustic alkali and mercerizing it under tension in a wet state.
After that, this yarn is knitted into a knitted fabric, and then this knitted fabric is allowed to contract freely, the knitted fabric is allowed to absorb an aqueous caustic alkaline solution, and the knitted fabric is pulled up from the aqueous caustic alkaline solution and continued while keeping its water content low. The present invention relates to a method for mercerizing a knitted fabric, which is characterized by pulling the knitted fabric in the length direction and width direction, and then removing caustic alkali.

This invention method is a method in which mercerization is performed twice, once in the yarn state and once in the knitted fabric state.

Of these, the mercerization process performed on yarn is no different from the mercerization process that is normally performed.

In that case, the thread is maintained in a tensioned state, and in this state, the thread is impregnated with an aqueous caustic alkali solution, and the treatment is completed in a state in which the thread is sufficiently hydrated.

However, mercerizing the knitted fabric is a dry mercerizing process, in which the silk fabric is immersed in a caustic aqueous solution without tension, the fabric is sufficiently shrunk by absorbing the caustic alkali aqueous solution, and then dried. Only after the contained moisture is removed and the moisture content is reduced, the edges of the knitted fabric are fixed and kept taut in both the warp and the width.

In this respect, dry mercerization differs from conventional mercerization.

The knitting may be tubular or open.

In the case of a tubular shape, it may be cut open vertically to form an open shape, and then subjected to dry mercerization processing.

In the dry mercerizing process, the knitted fabric is impregnated with an aqueous caustic alkaline solution in a state where it can freely contract, and then the knitted fabric is pulled up from the aqueous caustic alkaline solution.

When the knitted fabric is pulled up from the caustic aqueous solution, the knitted fabric contains at least twice its dry weight of the caustic aqueous solution.

Even when squeezed normally, the knitted fabric absorbs at least approximately the same weight of the caustic aqueous solution.

Even if the knitted fabric is sufficiently squeezed using a machine such as a mangle, the amount of the caustic alkali aqueous solution cannot be reduced to less than about 60% by weight of the dry weight of the knitted fabric.

Therefore, in normal mercerization processing, at least 60
It will be carried out in a state containing % by weight of water.

However, in the dry mercerization process, the knitted fabric is further dried to reduce the moisture content, and the knitted fabric is maintained in a tensioned state in the length direction and the width direction only after the moisture content is reduced.

In this respect, dry mercerization differs from ordinary mercerization.

In the method of this invention, the knitted fabric is pulled up from the alkaline aqueous solution, squeezed with a mangle, and then exposed to air at the appropriate timing to perform so-called nearing to sufficiently penetrate the alkaline aqueous solution into the knitted fabric.

During this time, do not put the knitted fabric under tension,
Allow it to contract freely.

After sufficiently permeating the aqueous alkaline solution into the knitted fabric and sufficiently shrinking the knitted fabric, while reducing the water content by drying, the aqueous caustic alkali solution is reduced to 50% by weight of the dry weight of the knitted fabric.
Continue until the following is achieved.

Among these, preferred is 40% by weight or less, and more preferred is 30% by weight or less.

Tension the knitted fabric in the length and width directions.

For this purpose, it is best to pull the knitted fabric in both directions mentioned above.
For this purpose, it is suitable to hang the knitted fabric on a tenter, fix both side edges of the knitted fabric with pins, etc., and then pull it.

When a knitted fabric is fixed with pins and pulled in air, especially in a state with low moisture content, the stitches are less deformed, the fabric can be pulled strongly enough, and the unevenness of the stitches in the width direction is reduced. be able to.

Therefore, high-quality treated products can be obtained by processing in the same way as textiles.

After the knitted fabric is stretched in the longitudinal and width directions in a low moisture state, the caustic alkali is removed in exactly the same manner as the conventional post-mercerization treatment.

That is, it is washed with warm water, neutralized with acid, and then washed with water to remove the caustic alkali.

The yarn used in this invention is not limited to one made only of cellulose fibers, but may be a yarn made by blending cellulose fibers with other fibers, such as polyester fibers.

Cellulose fibers are usually cotton, but may also be recycled fibers such as staple fibers and cupro fibers.

Further, the knitted fabric may be a mixture of cellulose fibers and other fibers.

The caustic aqueous solution used in the method of this invention is the same as the conventional one.

However, compared to the aqueous caustic alkaline solution used in the form of yarn, the aqueous caustic alkaline solution used in the form of knitted fabric may have a slightly lower concentration.

Specifically, the caustic alkali aqueous solution in the form of thread has a caustic alkali concentration of 12 to 30% by weight,
Therefore, in terms of Baumé, it is appropriate to have a Baumé temperature of 20 to 35 degrees, but the caustic alkali aqueous solution in the state of knitted fabric has a caustic alkali concentration of 8 to 25% by weight, and therefore, in Baumé terms, it is 15 degrees. It is appropriate that the angle is between 30 degrees and 30 degrees Baume.

As the caustic alkali, both caustic soda and caustic potash can be used, but caustic soda is preferably used.

The conditions for dry mercerization, which is performed later on as a knitted fabric, may be weaker than the conditions for ordinary mercerization that is generally performed on the yarn.

Further, as in ordinary mercerization processing, a surfactant may be added to the aqueous caustic alkaline solution during dry mercerization processing in order to aid in penetration of the solution.

In addition, various auxiliary agents can be added as necessary.

Mercerizing the thread can be done by simply pulling the thread taut rather than pulling it.

Even if it is pulled, it will have a constant force up to 20 inches.

In dry mercerization processing of a knitted fabric, the knitted fabric is tensed and pulled in the width direction and length direction while maintaining a low moisture state.

The tension is 10 to 30% in the length direction and 2% in the width direction.
A suitable range is 0 to 60%.

According to the method of this invention, since the yarn is mercerized, the gloss, shape stability, and strength of the yarn are already improved.

Since such yarns are knitted to form a knitted fabric, the knitted fabric has good gloss and excellent shape stability and strength.

Since such a knitted fabric is further subjected to mercerization processing, the knitted fabric becomes even more glossy, has a stable shape, has excellent strength, and has good dyeability.

Moreover, since the knitted fabric is in a state where it can freely contract when absorbing the caustic alkali aqueous solution, the yarns absorb the caustic alkali and swell without the mutual spacing being fixed.

Next, the knitted fabric is pulled in the length and width directions while keeping it in a low moisture state, so the stitches are less likely to deform.
It can be stretched evenly in both the width and length directions, and the tensile magnification can be increased.

Therefore, according to the method of the present invention, it is possible to obtain a high-quality knitted fabric with good gloss, excellent shape stability, high strength, and good dyeability.

The inventive method provides these advantages.

Next, the method of the present invention will be explained in more detail with reference to Examples.

Example 60/2 After burning the yarn of S', it was bundled and immersed in a 25% by weight aqueous solution of caustic soda for 30 seconds.
The tension was maintained for 5 minutes while applying a tension of 5qI) in warm water at 0°C, and then I C1i/J! The mixture was neutralized in an acetic acid solution, thoroughly washed with water, dried, and rolled up into cheese.

The yarn thus obtained was knitted into jersey using a circular knitting machine.

The knitted fabric was opened, and 50 tons of highly sulfated castor oil (sulfation degree 10) was added to a 13% by weight aqueous caustic soda solution!
The knitted fabric was immersed in the added solution, and the pick-up rate was 120.
After squeezing to %, nearing was performed for 30 seconds.

The water content at this time is 100% by weight based on the dry weight of the knitted fabric.
Met.

In this state, it was put on a tenter and heated at 100° C. for 10 seconds while being stretched by 20% in the length direction and 50 inches in the width direction, and then heated at 140° C. for 30 seconds.

After that, wash with hot water at 80℃ and add 1cC/4
Neutralization was performed with an acetic acid aqueous solution of 1, washed with water, and then dried.

In this way, dry mercerization processing was performed.

The thus obtained knitted fabric was scoured at 80°C for 30 minutes with a mixed aqueous solution of a nonionic activator and soda ash, and then scoured at 90°C with an aqueous solution containing hydrogen peroxide and a stabilizer.
After bleaching for a few minutes and finishing with a fabric softener, a knitted fabric with a much better texture and luster than conventional mercerized fabrics was obtained.

In addition, the knitted fabric after the above-mentioned dry mercerization process was dyed with a reactive dye (remazol) by 5% o-w-f 4
Although dyed at 0 to 60°C for 60 minutes, it was possible to obtain a dyed product with the same density using 80 tbsp compared to a knitted fabric in which the yarn and knitted fabric were mercerized twice using the conventional method. did it.

This confirmed the superiority of the method of this invention.

Claims (1)

[Claims] 1 A yarn containing cellulose fibers is impregnated with a caustic alkaline aqueous solution, mercerized under tension in a wet state, then knitted to form a knitted fabric, and then this knitted fabric is placed in a state where it can freely contract and the knitted fabric is treated with caustic. A knitting process characterized by absorbing an alkaline aqueous solution, pulling the knitted fabric from the caustic alkali aqueous solution, and continuously pulling the knitted fabric in the length direction and width direction while reducing the water content, and then removing the caustic alkali. How to mercerize the ground.