JPS59168175A - Modification of cellulosic nonwoven fabric - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for modifying cellulosic nonwoven fabric. More specifically, there is no occurrence of 6 "moking" after wetting and drying,
The present invention relates to a method for modifying a cellulose nonwoven fabric that has excellent dimensional stability against water vapor or water.

Cellulose-based nonwoven fabrics have excellent antistatic properties and moisture absorption properties, so they are used in a wide range of fields such as interlining for clothing, sanitary products, and industrial materials. Since there are few intertwining points between fibers, the deformation due to external forces is large. In particular, cellulose-based nonwoven fabrics are highly deformed by external forces when wet, and as a result, the fibers gradually come off, causing so-called "momi".

Furthermore, cellulose-based nonwoven fabrics also have the disadvantage that once they come into contact with water, they swell to a large extent with water, resulting in poor shape retention and difficulty in handling.

Conventionally, methods to improve this drawback include coating the surface with resin.

Although it is true that this method can prevent 6-moisture after wetting and drying, the texture tends to become rough and hard due to the resin coating.Furthermore, this method does not provide enough protection against water vapor or water. It is difficult to impart dimensional stability.

The inventors of the present invention have arrived at the present invention as a result of intensive study on a method for preventing cellulose-based nonwoven fabrics from wobbling after wetting and drying and imparting dimensional stability against water vapor or water.

That is, the present invention is a method for modifying a cellulose nonwoven fabric, which comprises impregnating the cellulose nonwoven fabric with a mercerizing agent and then removing the mercerizing agent.

According to the present invention, it is possible to prevent cellulose-based non-woven fabrics from wobbling after wetting and drying without hardening the texture of the cellulose-based non-woven fabrics, and moreover, it is possible to prevent the cellulose-based non-woven fabrics from becoming resistant to water vapor or water. Since stability can be imparted at the same time, handling over humid eaves or under humid conditions becomes extremely easy.

The present invention will be explained in detail below.

The cellulose fibers used in the present invention include natural cellulose fibers such as cotton, hemp, and flax, hiscose process rayon, cupraammonium rayon nanoregenerated cellulose fibers, and mixtures of both. .

Furthermore, there is no problem in mixing other types of fibers as long as the characteristics of the cellulose fibers are not substantially impaired. The permissible mixing limit for other types of fibers used in combination with cellulosic fibers is generally 50% by weight or less, based on the total N content of the side fibers.

The fiber locker method and
Conventionally known manufacturing methods such as a dry method such as a stitch method, a wet method such as a paper making method, a direct method such as a spray method and a spunbond method can be used.

Furthermore, it is desirable to increase the number of intertwining points between fibers by the needle punching method because it improves the mechanical properties of the nonwoven fabric.

In the present invention, a cellulosic nonwoven fabric is impregnated with a mercerizing agent, and then the mercerizing agent is removed from the nonwoven fabric.

The mercerization agents used in the present invention include caustic alkali,
One or a mixture of two or more selected from organic amines, ammonia, and quaternary ammonium salts may be used. The mercerizing agent may be diluted with other substances as long as it does not interfere with the processing of the mercerizing agent. The usage properties of these mercerizing agents are 1 to 60% by weight aqueous solution for caustic alkali, preferably 3 to 40% by weight for organic amines, and 20% by weight for organic amines.
An aqueous solution containing at least 40% by weight, preferably at least 40% by weight, or an organic amine containing 100% by weight, and an aqueous solution containing at least 40fti by weight of ammonia, preferably at least 60% by weight, or 100% by weight or more.
For 0-group ammonia, for quaternary ammonium salts, 15~
Examples include an 85% by weight aqueous solution, preferably 20 to 60% by weight. When using 100% mercerizing agent, it can be used in either gas or liquid form, but it is easier to process if it is used in liquid form.

Examples of caustic alkalis include sodium hydroxide, potassium hydroxide, lithium hydroxide, and cesium hydroxide.

Examples of organic amines include methylamine, ethylamine, propylamine, butylamine, amylamine, heptylamine, ethylenediamine, monoethanolamine, and hydrazine hydrazide.

Examples of quaternary ammonium salts include tetramethylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, and dimethylammonium hydroxide.

Methods for impregnating the material with the mercerizing agent include commonly used methods such as spraying, coating, and dipping, but any method may be used. The amount to be impregnated with the mercerizing agent is 10-150% by weight of caustic alkali, 20-150% by weight of organic amine, 40-15% by weight of ammonia, based on the weight of the fiber.
0% by weight, and 15-150% by weight for quaternary ammonium salts. The time for which the mercerizing agent is left to be impregnated varies depending on the nature of the mercerizing agent and cannot generally be specified.
The time is suitably at least 2 seconds, preferably at least 2 seconds. The temperature of the mercerizing agent impregnated into the fibers is -10℃ to 100℃ for an aqueous caustic solution, for organic amines, the freezing point of organic amines to 100℃, and for ammonia, the temperature is 7℃ to Zoo℃.
For quaternary ammonium salts, the temperature is in the range of -10°C to 100°C. To remove the impregnated mercerizing agent from the fibers, depending on the type of mercerizing agent, neutralization with a strong acid such as hydrochloric acid, sulfuric acid, etc., weak acid such as acetic acid, lactic acid, or succinic acid, or 80%
There are methods to remove with only warm water of ~100°C or by heating above the nodal point of the mercerizing agent, but if the method does not interfere with the effects of the present invention, a combination of these methods can be used for removal. I can do it. In short, the time for removing the mercerizing agent may be longer than the time required to remove the mercerizing agent from the fibers. However, the heating temperature is 2
If the temperature exceeds 00℃, yellowing and brittleness of the fibers will occur, so
It is undesirable to exceed ℃.

In the present invention, in order to further enhance the treatment effect, it is preferable to impregnate the nonwoven fabric with moisture prior to treatment with a mercerizing agent.

In the case of natural cellulose fibers, the amount of water to be included is adjusted to 3% or more, preferably 7% or more, and particularly preferably 12% based on the absolute dry weight of the fiber. 5- or more for regenerated cellulose fibers,
Preferably it is 12% or more. When the amount is less than 3% for natural cellulose and 5% for regenerated cellulose, it takes a long time for the treatment effect of the mercerizing agent to be fully exhibited. Methods of adding moisture include placing the fibers in an atmosphere that maintains a certain amount of moisture in the fibers, spraying water on the fibers, coating the fibers with water, and placing the fibers in a bath containing water. There is a method of soaking the fibers, or a method of removing part of the water from the fibers after the above method and keeping the water content in the fibers constant, but either method may be used.

In the method of the present invention, when the cellulose fibers are regenerated cellulose fibers, prior to the mercerizing agent impregnation treatment, a liquid that is sparingly soluble in the mercerizing agent and adsorbable to the regenerated cellulose fibers or a mercerizing agent is added to the surface of the regenerated cellulose fibers. It is desirable to add a substance that is refractory to the regenerated loin fibers and has the ability to form a film on the surface of the regenerated loin fibers to prevent adhesion between the single filaments during treatment.

Liquids that can be adsorbed to regenerated cellulose fibers include aliphatic and
These include aromatic hydrocarbons, fats and oils, and surfactants.
Among these, those that are liquid at room temperature are preferred. Here, "poorly soluble in a mercerizing agent" refers to a compound having a solubility at a mercerizing temperature of 10 r or less per 100 mercerizing agent. Moreover, "capable of being adsorbed to regenerated cellulose fibers" means that the contact angle formed between the liquid and the regenerated cellulose fibers is 110 degrees or less.

The amount of the liquid attached is preferably in the range of 5 to 15% by weight based on the weight of the fibers. The substance having film-forming ability preferably has a molecular weight of 10,000 or more, and the amount of adhesion is preferably in the range of 0.5 to 10 i based on the weight of the fiber. Polymers capable of forming a film include water-soluble polymers and water-dispersible polymers.

Further, in the present invention, it is preferable that the nonwoven fabric is stretched with a mercerizing agent applied thereto, and the mercerizing agent is preferably removed in the stretched state. Here, the state in which the nonwoven fabric is impregnated with a mercerizing agent refers to the state in which the nonwoven fabric is sufficiently plasticized. In the present invention, the elongation rate in the state impregnated with the mercerizing agent is the dimension before impregnating with the mercerizing agent (hereinafter referred to as the original size).
1% or more, preferably 3 to 40 inches.

The elongation of the nonwoven fabric may be applied in one or both of the warp and weft directions. When stretching in the warp/line drawing direction,
Although it may be freely contracted in the direction perpendicular to the stretching direction, it is preferable to fix it to the original size. When extending in the red/line drawing direction, it may be extended in both directions simultaneously or sequentially. When expanding sequentially, the direction perpendicular to the stretching direction may or may not be constrained during the first stage of expansion, but the direction perpendicular to the stretching direction may also be stretched relative to the original size during the second stage of expansion. preferable.

The stretching methods include the so-called roll stretching method that utilizes the surface speed ratio of a 2-meter presser roller, a pin tenter,
A method using a clip tenter or the like can be used.

The nonwoven fabric thus stretched is then subjected to a step of removing the mercerizing agent while maintaining the same stretching rate or a lower stretching rate, thereby demercerizing the fabric. When removing the north side of the mercer, it must be kept stretched to a size larger than the original size; however, it is not preferable to extend the fiber beyond the stretch rate when applying the mercerizing agent, as this increases the internal structural strain of the fiber.

In addition, the bone-dry fiber weight mentioned in the text refers to the method described in Japanese Industrial Standard JIS L-1015, that is, the state in which the fiber is dried to a constant weight in heated air at a temperature of 105 ± 2 ° C. The weight of the resulting product is 0.
The sample was left in an atmosphere with a temperature of 20°C and a relative humidity of 65 for 48 hours or more to adjust the humidity, and was used as a test sample. The degree of ``momoke'' was judged visually in five stages.

Grade 5: Good appearance, same quality as the original fabric Grade 4: There are small "moke" here and there. Grade 3: There are mottled 6" large and small "marks". Extremely large "6" cracks occurred on the entire surface (dimensional change rate) The temperature was 20°C and the relative humidity was 55%.

Create a test piece from the sample. The size of the test piece is 60 mm in length.
The width is 2.5 m, and marks are made at 25 cm on each side from the center point in the length direction.

(The length between two points is 50 pieces) Dimensional change A: 50 according to the following formula
℃ and relative humidity of 80% for 24 hours (crn)) Note that the numerical values are expressed as the total value of longitude and latitude.

<Swelling degree> The swelling degree was expressed by the following formula.

(B-A)/AX100=swelling degree (@ A: absolute dry weight of the test sample B: the test sample was immersed in water at room temperature for 30 minutes, then,
Using a centrifuge with a diameter of 23 cm, the rotation speed was 350 Orp, p
Fiber weight after dehydration for 5 minutes at , m, to remove adhering water on the fiber surface Example 1 Single yarn thickness: 2 d, fiber length: 25 strands, single yarn thickness: 2 d.

Date 25 made of viscose method rayon with a fiber length of 50
f/m'' nonwoven fabrics were each produced by a conventional wet method.

These nonwoven fabrics were left in a constant temperature and humidity chamber at 20°C and a relative humidity of 65 cm for 24 hours, and s% and 1% were added to the absolute dry weight of the fibers, respectively.
The water content was adjusted to 2%. Then, the nonwoven fabric was immersed for 60 seconds in a 20% by weight aqueous sodium hydroxide solution, ethylenediamine, liquid ammonia, and a 40% by weight tetramethylammonium aqueous solution. The liquid was squeezed so that the pickup rate was 100%, and the sample was expanded by 2 times in the warp and weft compared to the dimensions before mercerization (hereinafter referred to as the original size). The treatment temperature is 20℃ for sodium hydroxide aqueous solution and 20℃ for ethylenediamine.
The temperature was -40°C for liquid ammonia and 25°C for a 40% by weight aqueous tetramethylammonium solution. In addition, the elongation in the warp direction was carried out by changing the surface velocity of the pair of rows 2 before and after immersion on the north side of Marcel. It was allowed to contract freely in the latitudinal direction. Then, elongation was performed in the weft direction using a pin tenter while impregnated with the mercerization agent. The surface speed of the roller and the speed of the pin tenter were synchronized and restrained so that the elongation in the warp direction was maintained at 2% of the original size while being elongated in the weft direction. Elongation in the latitudinal direction took 10 seconds. The mercerizing agent was removed using a pin tenter, and during the removal of the north side of the mercer, new elongation occurred, maintaining an elongation rate of 2 inches in both longitudinal and latitude. To remove sodium hydroxide, immerse in hot water at 90°C for 60 seconds, then neutralize with 3% acetic acid at 20°C and wash with water.
C. for 60 seconds in a hot air atmosphere, and in the case of 40% by weight tetramethylammonium, the same procedure as with sodium hydroxide was carried out. The results are shown in Table 1.

According to the present invention, not only is it possible to prevent the "6" peeling after wetting and drying, but also the dimensional stability in a constant temperature and high humidity atmosphere is good.

Table 1 Example 2 Using a 75d/36f cuproammonium rayon filament, a fabric weight of 20y/m' was obtained by a conventional wet method.
A continuous fiber nonwoven fabric was created. Next, three pieces of sorbitan monolaurate were attached to the nonwoven fabric M amount. Furthermore, the nonwoven fabric was placed in a constant temperature and humidity chamber at 20°C and relative humidity of 65% for 24 hours.
The mixture was left to stand for a period of time, and the moisture content was adjusted to 12 cm based on the absolute dry weight of the fibers. The nonwoven fabric was immersed in liquid ammonia at -40°C for 20 seconds, and then hot air at 160°C was applied for 60 seconds to remove ammonia from the nonwoven fabric. The elongation of the warp and weft was done in the same manner as the example work, and both the warp and weft were elongated by 1% relative to the original size.

Further, sorbitan monolaurate was removed by scouring at 70°C for 20 minutes. During scouring, the dimensions before scouring were maintained.

Dimensional stability in a humid atmosphere is also good.

Margin below Table 2

Claims (1)

[Claims] A method for modifying a cellulose nonwoven fabric, which comprises impregnating the cellulose nonwoven fabric with a mercerizing agent and then removing the mercerizing agent.