JPS6215655B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a woven or knitted fabric having excellent water absorption properties and containing 30% by weight or more of fibers having fine grooves on the surface (grooved fibers). Nowadays, thermoplastic synthetic fibers, particularly polyester fibers, are used in an extremely wide range of applications as textile materials for clothing, but they have the disadvantage of poor hygroscopicity and water absorption performance. Therefore, many studies have been made to impart hydrophilicity to hydrophobic fibers. In other words, hydrophilicity can be achieved by (1) copolymerizing or blending polyalkylene glycol, its derivatives, or metal salts with a hydrophobic polymer, (2) imparting a porous structure to the fiber, or (3) post-processing. Methods for attaching substances to woven or knitted fabrics have been proposed and partially implemented. In method (1), it is possible to impart hydrophilicity to a certain extent to the fibers, but in order to provide sufficient performance comparable to natural fibers, the amount of modification increases, and as a result, the fiber properties of the basic polymer deteriorate significantly. This makes it impractical. In addition, method (2) is an interesting method as it attempts to utilize the capillary condensation effect rather than imparting chemical hydrophilicity, and it is true that the hygroscopicity under high humidity is significantly improved. However, in order to do so, it is necessary to make a considerable portion of the fibers porous, which causes the same problem as (1). Furthermore, although method (3) is practical and widely used, its effectiveness when considering the comfort of wearing it is questionable simply because it is easy to get wet with water, and the biggest drawback is that it is resistant to washing. It is inferior to sex. As described above, many research proposals have been made to date on hydrophilic or hygroscopic fibers, but these are simply attempts to improve the hydrophilic and hygroscopic properties of fibers, and from the viewpoint of clothing hygiene, sweat wicking The textiles or woven or knitted fabrics were not designed with comfort in mind. The inventors of the present invention have repeatedly conducted basic studies to find out what kind of performance a woven or knitted fabric should have that does not have these drawbacks and is comfortable to wear when sweating. We have succeeded in providing a woven or knitted fabric that does not cause discomfort. According to the research conducted by the present inventors, when considering the climate inside clothing during sweating, the parameters that can be changed independently depending on the clothing material are (1) hygroscopicity, (2) surface wettability, and (3) water absorption. (water retention) and (4)) dryness and moisture permeability. Among these, (4)
It has been found that (1), which has been considered the most important until now, is only desirable if it has good performance, and has little effect on actual use. What is important is requirement (3), and we also found that (2) is important in order to achieve the performance of (3) in a short period of time. Generally speaking, when considering the mechanism of sweating, changes in the climate inside clothing can be divided into the following four periods. That is, the first period is the insensible excretion period, and the amount of sweat is considered to be about 5 to 20 g/m ² hr, which corresponds to when living a normal life indoors at 25° C. and 70% RH. In this state, the humidity inside the clothing is below 70 to 80% and there is no discomfort. The second period is the period when thermal sweating begins, and the amount of sweat is equivalent to that during light labor, 20~
It is about 50g/m ² hr, and the humidity inside the batter is 60 to 100%. If this condition continues, it is thought that if the underwear has good moisture permeability or absorbency, the humidity inside the garment will not change, but if the underwear has poor moisture permeability or moisture absorption, the humidity inside the garment will increase and the person will feel uncomfortable. The third period is a period in which the amount of sweat increases with time, and the amount of sweat corresponds to moderate to heavy labor and is considered to be 50 to 120 g/m ² hr. In this state, the inside of the clothes becomes wet, and unless the underwear absorbs sweat, the skin gets wet and causes extreme discomfort. The fourth stage is a period in which the human body adapts to the environment and the amount of sweat gradually decreases, and the underwear becomes completely wet, and the only way to relieve the discomfort is to change the underwear. In the first period, the hygroscopicity and moisture permeability of the fiber material are relevant, but since the amount of perspiration is small, there is no difference depending on the material, and there is no discomfort, so there is no problem. Also, in the fourth period, there are no differences between materials for the reasons mentioned above, and it is not the place to discuss the performance design of materials. Therefore, it is in the second and third stages that differences occur depending on the fiber material. Most of the previous proposals focused on clothing that lasted for the second period, and therefore making the fiber absorb moisture was considered an important point. However, imparting hygroscopic properties to hydrophobic fibers is a very difficult problem, and at present no practical product has yet appeared. According to the results of the actual wear test carried out by the present inventors, it was concluded that there is essentially no discomfort in the second stage, and discomfort is felt in the third stage, when the skin feels wet. Ta. In other words, the hygroscopicity of the fibers is not a very important factor, but how to keep the skin dry is what is important, and in that sense, the water absorption and wettability of the fibers are the most important. . It has also become clear that wettability is necessary only to exhibit water absorption performance in a short period of time, and that too easy wettability is undesirable because it gives a sticky feeling. The present invention has been designed from a different perspective than the conventional one, in which the hygroscopicity of the fibers is not necessary, but the water-absorbing performance is the most important, and a novel water-absorbing woven or knitted fabric has been achieved. That is, the surface of the fiber has six or more grooves continuous in the fiber axial direction, the width of the groove is 0.1 to 4μ, the depth is 2 to 10μ, and the proportion of the groove is equal to the cross section of the latent groove-containing fiber. It is a woven or knitted fabric with excellent water absorbency, containing 30% by weight or more of thermoplastic synthetic fibers, which is 10% or more per weight. As described above, it is essential that the thermoplastic synthetic fibers that constitute the present invention have grooves, and there is no need for a modifier to further impart hydrophilicity, so the fiber performance of the main polymer can be maintained as is. There are advantages that can be maintained. Typical examples of the polymer constituting the thermoplastic synthetic fiber of the present invention include polyolefins such as polyethylene and polypropylene, isotactic or atactic polyethylene, alkyl- or halogen-substituted polystyrene, 6-nylon, 66-
There are polyamides such as nylon, polyesters copolymerized with polyesters such as polyethylene terephthalate, and polyesters such as polymethacrylates such as polymethyl methacrylate. Additives such as disinfectants and other known additives
% or less, but the most preferred examples are realesters. Furthermore, the fibers made of these polymers may be composite or mixed fibers of the above-mentioned same or different types of polymers. The present inventors have found that as a method of imparting water absorbency to fibers without adding a moisture modifier, it is most preferable to create grooves on the fiber surface and thereby utilize the effect of capillary rise. I came to the conclusion that there is a method. Several attempts have been made to create capillaries by changing the cross-sectional shape of the fibers, but these have not been satisfactory as explained below. It has a continuous groove in the direction of the fiber axis of the book, and the width of the groove is 0.1 to 4μ and the depth is 2 to 10μ.
and the area of the groove in the fiber cross section is 10%
Only by using the above-mentioned groove-containing fibers can excellent water absorbency be exhibited. The water absorption rate and wicking property referred to in the present invention are measured as follows. (1) Water absorption rate: A sample of tubular knitted fabric was immersed in pure water at 25°C for 30 minutes and then heated in a centrifugal separator set at the specified rotation speed for 10 minutes.
After dehydrating for a minute, the weight is measured and defined as W ₁ . Next, the same sample is completely dried and W ₀ is measured. Water absorption rate = W ₁ −W ₀ /W ₀ ×100 (%) The dehydration force G is expressed as the centrifugal force divided by g (=980 cm/sec ² ). G=(2πr/60) ² /980×r r: Radius of centrifuge (11.75 cm was used) : is the rotational speed measured after 9 minutes (rpm) (2) Wicking property: 25℃, A sample that had been kept in a 65% RH room for at least 24 hours was stretched horizontally on a glass plate, and a 0.4 cc water droplet was dropped from a height of 10 mm using a biuret, and the water droplet was completely absorbed by the cloth and exhibited specular reflection. The time it took for it to disappear. (3) Water absorbed by filter paper: Prepare two almost identical samples, and centrifugally dehydrate the two sheets simultaneously using the method described above to measure water absorption. Measure the water absorption rate of one sheet, place the remaining sheet on a polyethylene sheet (the bottom is a velvet sheet placed on a horizontal board), cover it with a polyethylene sheet with a 50φ hole, and place it on a filter paper ( No.(1)
Place four sheets of filter paper on top of each other over the hole, apply a load of 3 g/cm ² from above for 1 minute, and measure the amount of water absorbed by the filter paper. Here, the water absorbency naturally changes depending on the magnitude of G. As shown in Examples below, when G is small (100 or less), most materials exhibit high water absorption, but when they come into contact with the skin, they wet the skin and cause discomfort when worn. On the other hand, materials with a G value of 1000 or more that exhibit high water absorption do not make the skin feel wet despite having a high water absorption rate. The woven or knitted fabric of the present invention has the latter performance. The groove-containing fiber according to the present invention has at least six grooves per single fiber having a width of 0.1 to 4 μm and a depth of 2 to 10 μ that are substantially continuous in the fiber axis direction, and the occupation rate of the grooves is 10%. That's all. Here, if the width of the groove exceeds 4μ, as shown in Comparative Example 2, G>
If the water absorption rate at 1,000 μm is less than 0.1μ, and if the number of grooves is 5 or less, the area ratio of the grooves in the fiber cross section, that is, the groove occupancy (groove occupancy A = area of the grooves/potential content). Area of groove fiber ×
100) to 10% or more, and therefore it is impossible to obtain a high water absorption rate when G>1000. In the shape of the groove-containing fiber of the present invention, it is more preferable that the width of the groove is 0.5 to 2μ, the depth of the groove is 6 to 8.5μ, the number of grooves is 8 or more,
This is the case when a grooved fiber as shown in the figure in which 20% or more of grooves are facing each other in the same number is used. Furthermore, if the shape of the groove-containing fiber of the present invention is considered as an optimal embodiment, the number of grooves described above is 6 or more, the width of the groove is 0.1 to 4μ,
In addition to groove-containing fibers of the groove-opposing type that satisfy the requirements of a depth of 2 to 10 μm and a groove occupancy rate of 10% or more, the distance between the bottoms of opposing grooves is 1.5 to 4 μm, and the side wall closest to the adjacent grooves. This is the case of groove-containing fibers with a distance of 2 to 3.5μ. In addition, when using the groove-containing fiber of the present invention,
It is surprising that when G>1000, the water absorption rate is greater than the groove occupancy rate A, and this is thought to be due to the creation of secondary capillaries between the fibers, which is one of the characteristics of the woven or knitted fabric of the present invention. The method for producing the latent groove-containing fiber that can provide the above-mentioned groove-containing fiber according to the present invention includes (1) composite spinning of two or more polymers with different solvent extractability, and one component is dissolved or peeled off in the processing step; (2) Multi-layer composite spinning of the same or different types of polymers with different dissolution rates is performed, and the one-component polymer portion is melted or peeled off during the processing process. There is a method that uses the groove as a groove. According to the method for producing groove-containing fibers according to the present invention, grooves can be made apparent in the latent groove-containing fibers before or after spinning, knitting, and weaving. This has the great advantage that the grooves will not be crushed or destroyed. The above-mentioned woven or knitted fabric according to the present invention has somewhat improved wicking properties and becomes easier to wet. moreover,
Another feature of the woven or knitted fabric of the present invention is that it significantly improves the durability of the finishing agent. Therefore, by using a known sweat-absorbing and hydrophilic finishing agent, we can provide a woven or knitted fabric that instantly absorbs sweat from the human body and does not leave the skin feeling wet, and its performance is almost permanent. It is something like that. Examples of the cross-sectional shape of the groove-containing fiber of the present invention are shown in FIGS. 1 and 2. The width and depth of the grooves referred to in the present invention are the average values of each groove, and the groove occupancy rate A is calculated from the micrograph. Figures 3 and 4 show latent groove-containing composite fibers before obtaining the groove-containing fibers shown in Figures 1 and 2, respectively, which have been subjected to spinning, drawing, yarn processing (for example, false twisting), and before knitting and weaving. Alternatively, the fibers shown in FIGS. 1 and 2 can be obtained by later removing part or all of the shaded areas (in this case, the part of the polymer that is not shaded is used as the groove-containing fiber of the present invention). There is no problem in removing them at the same time within a range that satisfies the following.) Hereinafter, the characteristics of the woven or knitted fabric of the present invention will be explained with reference to Examples and Comparative Examples. Example 1 High-pressure polyethylene and [η] = 0.68 dl/g polyethylene terephthalate were introduced into the spinning head at a ratio of 35:65 from each extruder, and the polymer flows were distributed and spliced to form a cross-section as shown in Figure 3. After obtaining a fiber with a plane, it is stretched 4 times to 115 dr/24
And so. After making this into a tubular knitted fabric, the polyethylene was extracted and removed in a perchloren bath at 80°C.
The number of grooves having the cross section shown in the figure is 10, the width of the groove is 2μ,
Groove depth 8.5μ, groove occupancy rate 40%, distance between the bottoms of opposing grooves 2.5μ, minimum distance between adjacent grooves sidewalls 2.1μ
A knitted fabric made of grooved fibers was obtained. This knitted fabric is the fifth
~As shown in Figure 6, the water absorption rate at G = 1200 is approximately 70
%, and the moisture content absorbed by the filter paper was 1.5%. From this result, it can be seen that even if it absorbs about 70% of water, it has a sweat absorption performance similar to that of cotton, leaving almost no wet feeling on the skin. Example 2 and Comparative Examples 1 and 2 Polyethylene and polyethylene terephthalate
The same method as in Example 1 was used except that the time was set at 20:80.
After obtaining a drawn yarn of 94 dr/24, a tubular knitted fabric was made in the same manner, and the polyethylene was extracted and removed (Example 2). Meanwhile, ordinary polyester filament
A tube knitted fabric of 75 dr/24 was made (Comparative Example 1). A tubular knitted fabric made of 75dr/24 having 4 grooves after polyethylene extraction, a groove width of 6 μm, and a groove depth of 5.5 μm was made (Comparative Example 2). These results, including those of Example 1, are shown in Table 1 in comparison with a tube-knitted fabric of single yarn No. 48 scoured bleached cotton.

[Table] As can be seen from Table 1, the fibers of the present invention have little improvement in hygroscopicity. However, although its wicking properties are inferior to cotton, it is improved compared to regular fibers with a round cross section. Wicking properties are better when the groove width is smaller. Moreover, the water absorption rate when the dewatering force (G) is changed is shown in FIG. 5, and the water absorbed by the filter paper at each water absorption rate is shown in FIG. The characteristics of the present invention are shown in the water absorption rate and water absorbed by the filter paper as shown in FIGS. 5 and 6. That is, at G=1200, where most of the water adhering to the knitted fabric is dehydrated, Comparative Example 1 retains only 3% of water, whereas Example 2 retains 40% of the water. In addition, when the width of the groove is wide as in Comparative Example 2, the water absorption rate is good when G is small, but when G = 1200,
It will be less than 10%. Furthermore, as shown in Figure 6,
When the water absorption rate exceeds 50%, the water absorbed by the filter paper increases rapidly. On the other hand, Examples 1 and 2 exhibit behavior similar to cotton. Example 3 A polyethylene terephthalate obtained by copolymerizing polyethylene terephthalate with [η] = 0.68 dl/g and 3.5 mol% sodium 3,5-di(carbomethoxy)-benzenesulfonate was composite-spun, and the diagonal lines as shown in Fig. 4 were obtained. A latent groove-containing fiber whose portion was a copolymerized component was obtained. Here, the composite ratio was set to 1:1, and other conditions were kept almost the same as in Example 1 to obtain a drawn yarn of 105 dr/24. After false twisting this fiber,
After making 32 gauge smooth knit and scouring it, we reduced it by 30% in a 40g alkaline bath, and found that the width of the groove was approximately 1.3μ, as shown in Figure 2, although it was slightly deformed. The fiber had a depth of 6.7μ and a groove occupancy rate A of 28%. This knitted fabric had a good wicking property of 3 seconds, and a water absorption rate of 103% at G=400 and 53% at G=1200. Example 4 0.5% of a sweat-absorbing finishing agent mainly composed of low molecular weight polyester copolymerized with polyethylene glycol was applied to the tubular knitted fabric of Example 2. When we measured the wicking property of this knitted fabric, it was instantaneous (0
(seconds) absorbed water droplets. Wash this item 10 times (1
The wicking property after each wash was 10 minutes) was 3 seconds. The wicking property after washing 50 times was 5 seconds. Comparative Example 3 An attempt was made to directly obtain the groove-containing fiber of the present invention by spinning polyethylene terephthalate with [η] = 0.68 dl/g through a square-shaped spinning hole, but the groove-containing fiber of the present invention was partially fused. The desired groove-containing fibers could not be obtained due to the occurrence of adhesion. Comparative Example 4 Polyethylene terephthalate with [η]=0.68 dl/g was spun from a square-shaped spinning hole and drawn to obtain a 75 dr/24 grooved fiber having four grooves, two facing each other. This groove had a width of 0.2μ and a depth of 2μ.
When this fiber was then subjected to normal false twisting on a plate at 200°C, the protrusions between the grooves cracked (fibrillated) and a considerable portion of the grooves collapsed. The water absorption rate (G = 1200) was measured using this deformed grooved fiber as a tubular knitted fabric.
It was 5.2%, showing almost no effect.

[Brief explanation of the drawing]

Figures 1 and 2 are examples of cross sections of the groove-containing fibers of the present invention, and Figures 3 and 4 are latent groove-containing fibers before obtaining the fibers shown in Figures 1 and 2, respectively. . 5 and 6 illustrate experimental results for explaining the features of the present invention. Figures 5 and 6
In the figure, 1 shows the results of Example 1, 2 shows the results of Example 2, 3 shows the results of Comparative Example 1, 4 shows the results of Comparative Example 2, and 5 shows the results of cotton.

Claims (1)

[Claims] 1. Grooved fibers obtained by removing at least one polymer before or after weaving or weaving latent grooved fibers made of two or more types of thermoplastic polymers having different solubility. % or more, the groove-containing fibers have a width of 0.1 to 4 substantially continuous in the fiber axis direction.
1. A woven or knitted fabric with excellent water absorption, characterized in that it has at least 6 grooves of 2 to 10 μ in depth per single fiber, and that the occupation rate of the grooves is 10% or more per fiber cross section. 2. The woven or knitted fabric with excellent water absorbency according to claim 1, wherein the number of grooves in the groove-containing fibers is 8 or more per single fiber. 3. The woven or knitted fabric with excellent water absorbency according to claim 1 or 2, wherein the groove occupancy of the groove-containing fibers is 20% or more. 4. The woven or knitted fabric with excellent water absorbency according to any one of claims 1 to 3, wherein the width of the grooves in the grooved fibers is 0.5 to 2μ. 5. The woven or knitted fabric with excellent water absorbency according to any one of claims 1 to 4, wherein the depth of the grooves in the grooved fibers is 6 to 8.5 μm. 6. A woven or knitted fabric with excellent water absorption according to any one of claims 1 to 5, which uses a grooved fiber having an even number of grooves and half of the grooves facing each other. . 7. Any one of claims 1 to 6 using groove-containing fibers in which the distance between the bottoms of opposing grooves is 1.5 to 4μ, and the distance between the closest side walls of adjacent grooves is 2 to 3.5μ. Woven or knitted fabric with excellent water absorbency.