JPH0376818A - Polyamide/polyester two-component fiber and its production - Google Patents

Abstract

PURPOSE:To obtain the title fiber easy to form webs through special treatment of the final fiber and capable of giving e.g. nonwoven fabrics excellent in bulkiness and elastic recovery, and good in crimping potential by conjugate spinning of a specific modified polyester and a polyamide. CONSTITUTION:Firstly, (A) a modified polyester prepared by copolymerization of 2-7mol%, based on the acid component, of 5-sodium sulfoisophthalate and (B) a polyamide are put to conjugate spinning. Subsequently, the resultant fiber is put to the first step drawing at such a ratio as to be 90-98% of the maximum draw ratio followed by limited shrinkage by a factor of 0.85-0.98 in hot water at 80-90 deg.C and then heat treatment at 180-200 deg.C in a tensioned state, thus obtaining the objective side-by-side type fiber with the number of spiral crimp of 0/25mm in an atmosphere of a temperature 20-30 deg.C and a relative humidity 40-75%, developing crimps when brought into contact with water.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is an excellent method suitable for obtaining a dry nonwoven fabric, a spun yarn, or a woven or knitted fabric that is easy to form into a web and has excellent bulk and elastic recovery properties. The present invention relates to a composite fiber having a latent crimp ability.

[Prior Art] Polyester fibers have excellent mechanical properties, thermal dimensional stability, washability, etc., and are therefore used in an extremely wide range of applications. Among these, fields that come into contact with the human body, such as medical disposable materials, fields that do not allow the use of microglass fibers, such as clean room, automotive air/oil, and food liquid filters, where microglass fibers cannot be used, or fields that cannot be used with cotton pads. There is a demand for bulky and highly stretchable nonwoven fabric materials.

In addition, in the field of general clothing, there is a demand for spun yarns or woven or knitted fabrics with good stretchability and elastic recovery properties as sports woven or knitted fabric materials. Among these, in the field of non-woven fabrics, where market needs are particularly high, a method using polyester composite fibers has been proposed to provide bulk (Japanese Patent Application Laid-open No. 78214/1983).
.

According to this proposal, the generation of neps and unopened lines during the carding process is attempted to be suppressed by applying a specific mechanical crimp to a composite fiber made of two specific types of polyester; The shrinkage expression is not sufficient,
If the properties of the constituent polymers are significantly changed in order to increase the number of expressions, the crimp fastness decreases and there is a drawback that a simple external force causes the phenomenon of sagging. Although a combination of different types of polymers is desirable for composite fibers that do not exhibit this sagging phenomenon, different types of polymers generally have problems in mutual adhesion and are easily peeled off. One of the inventors of the present invention proposed a composite fiber consisting of a combination of metal sulfonate group-containing modified polyester and polyamide (Japanese Patent Publication No. 45-28728). Furthermore, it is shown in various documents that the properties of this metal sulfonate group-containing modified polyester/polyamide composite fiber vary depending on the manufacturing conditions.
No. 55807, Special Publication No. 57-55808, Special Publication No. 63
-44843 and Japanese Patent Publication No. 63-44844).

Unfortunately, however, in all of these proposals, even though the number of spiral crimps is acknowledged to be drastically reduced, the reality is that the productivity of carding is significantly reduced due to the small amount of spiral crimps that are still mixed in, making it difficult for actual industrial production to occur. The use of has been restricted. In addition, a nonwoven fabric manufacturing method in which the composite fibers are divided into component fibers after passing through a carding process has been proposed in Japanese Patent Publication No. 52-30628;
It has not been shown to do so.

[Problems to be Solved by the Invention] In the present invention, the carding process consists of only normal mechanical crimping without any spiral crimping, and therefore can be carded by a normal spinning method, and the formed web is Spiral crimp occurs in the subsequent hydroentanglement-drying process or mechanical entanglement-heat treatment process, giving an extremely bulky nonwoven fabric. The object of the present invention is to provide a composite fiber that can be made into a woven or knitted fabric with a unique texture by adding bulk through processing.

[Means for Solving the Problems] That is, the present invention provides: (1) a modified polyester component and a polyamide component in which 2.0 to 7.0 (mol)% of 5-sodium sulfoisophthalic acid is copolymerized with respect to the acid component; Side-by-side consisting of
Side-type composite fibers that have substantially 0 spiral crimp/25 mm under an atmosphere of temperature 20 to 30°C and relative humidity 40 to 75%, and that crimp develops upon contact with water. A polyamide/polyester two-component fiber characterized by:

(2) 40-18 in the relaxed state before or after contact with water
The polyamide/polyester bicomponent fiber according to claim 1, wherein the number of mechanical crimps becomes substantially 0/15 mm by dry heat treatment at 0° C., and only spiral crimps appear after cooling.

(3) Polyamide and a modified polyester obtained by copolymerizing 2.0 to 7.0 (mol)% of 5-sodium sulfoisophthalic acid to the acid component are composite-spun, and then the maximum drawing ratio of the fiber is 90 to 7.0 (mol)%. After the first stage stretching at a magnification of 98%,
A method for producing polyamide/polyester two-component fiber, which is characterized by limited shrinkage of 0.85 to 0.98 times in warm water at 80 to 90°C, and further heat treatment at 180 to 200''C under tension.

(4) Claim (3) in which mechanical crimps of 8 pieces/25 mm or more are applied after heat treatment at 180 to 200°C under tension.
A method for producing a polyamide/polyester two-component composite fiber as described in .

It is related to.

The modified polyester of the present invention contains 5-sodium sulfoisophthalic acid at a ratio of 2% to the total acid components constituting the polyester.
．． 0 to 7.0 (mol)% copolymerized.2.
If it is less than 0 (mol)%, the adhesion to the polyamide is insufficient and some peeling may occur during handling in the next process, and if it exceeds 7.0 (mol)%, spinnability becomes difficult. Undesirable.

The base polyester to be copolymerized with 5-sodium sulfoisophthalate is mainly polyethylene terephthalate or polybutylene terephthalate, but copolymers and mixtures thereof may also be used. Of course, known third component copolymers can also be used as long as the basic performance is not impaired.

The polyamide constituting the other component of the present invention is mainly nylon 4, nylon 6, nylon 66, nylon 12
However, copolymers and mixtures of these may also be used.

Of course, copolymers of known components can also be used as long as the basic performance is not impaired.

Composite spinning can be performed using a normal melt spinning method, but the main point of the present invention lies in the drawing method.

In other words, the spun undrawn yarn is drawn in the first stage, and the maximum drawing ratio (the highest drawing ratio leading to cutting) is 90 to 98%.
After extreme stretching, conversely, limited shrinkage of 0.85 to 0.98 times is carried out in hot water at 80 to 90°C. A particularly preferable first stage stretching ratio is 95, which is the maximum stretching ratio.
~98%. If the maximum stretching ratio is less than 9θ%, the spiral crimp will not completely disappear when the next tension heat treatment is applied, and if it exceeds 98%, single yarns will break, resulting in roller wrapping, unstretchedness, and miscuts. This may cause frequent abnormalities.

If the magnification of the second stage stretching (so-called limited shrinkage) is less than 0.85, winding due to rollers will occur, and 0.9
If it exceeds 8 times, spiral crimp remains even after the tension heat treatment, which is not preferable.

In order to subsequently perform tension heat treatment at a temperature of 180 to 200°C, the tow under tension may be heated after the second stage stretching. Various methods can be used for heating, such as a heating roller method, a method of contacting a heating plate, and a method of passing through a space heated by infrared rays or various heaters. Since the tow shrinks due to heating, it is desirable that the traveling speed before heating is somewhat faster than the traveling speed of the tow after heating. 1
If the tension heat treatment is performed at a temperature lower than 80℃, the spiral crimp will not completely disappear, and if the temperature exceeds 200℃,
This is undesirable because deposits gradually form on the surface of a heating element such as a heating roll or hot plate that comes into contact with the tow.

To impart mechanical crimp to this tension heat treated tow,
A method of imparting mechanical crimp to ordinary polyester fibers may be used. For example, a push-in crimp method using a stuffer box is suitable. If necessary, an oil agent may be applied to the tow before pressing and crimping.

The number of mechanical crimps to be applied is preferably 8/25 mm or more. If the number is less than 8 pieces/25 mm, some spiral crimp remains, which is not desirable. Mechanical crimps of 12/25 mm or more are most preferred in the present invention.

The thus obtained composite fiber tow in which spiral crimp is completely latent is dried at a temperature below 40° C. and then cut into a predetermined length. If the drying temperature exceeds 40°C, a small amount of spiral crimp will develop and should be avoided. Further, in the present invention, bulkiness is finally obtained by spiral crimp, and there is no need to heat set to maintain mechanical crimp, as is the case with ordinary spun polyester cotton.

The thus obtained conjugate fiber of the present invention has completely latent spiral crimp, and therefore does not differ in appearance from ordinary short fibers for use in nonwoven fabrics or spinning. This short fiber can be made into a carded web or an air-laid web using a conventional method. The web may be made of the composite fiber of the present invention alone, but may also be mixed with other materials such as cotton, wool, bulb, rayon, polyester fiber, olefin fiber, or may contain various known adhesive fibers. .

When used as a non-woven fabric, the web is subjected to water jet entanglement or mechanical entanglement using needle punching, followed by drying/heat treatment. What is extremely interesting about this invention is that
Even with a stream of water at room temperature, spiral crimp appears, and when dried at room temperature, the spiral crimp disappears again, demonstrating shape memory performance. When it is desired to eliminate the shape memory performance and permanently develop only spiral crimp, it is recommended to perform stress-free heat treatment (tension-free drying in the case of hydroentangling) at a temperature of 40° C. or higher, preferably 60° C. or higher. During this heat treatment (or drying), the spiral crimp does not yet appear and the mechanical crimp disappears, and when the heat treatment (or drying) is finished and the material is cooled, only the spiral crimp appears. Therefore, the final crimped form of the web is a uniform, bulky nonwoven fabric with only spiral crimps and no mechanical crimps.

The conjugate fibers of the present invention and adhesive fibers can be blended, and after dry web production, adhesion can be performed by embossing and calendering using known methods. At this time, spiral crimp appears as it cools, and does not change even if it is subsequently immersed in water or dried.

When the composite fiber of the present invention is used for spinning, it is possible to obtain a stable fiber with only mechanical crimping and no spiral crimping. Therefore, by adjusting the mechanical crimping conditions, spinning suitable for various uses can be obtained. It becomes possible to manufacture yarn. Moreover, it can also be used as a yarn for carpets by taking advantage of its bulkiness, and can also be used as a wiping material for towels and other items.

It is also possible to add various additives and colorants to one or both components of the composite fiber of the present invention.

[Effects of the invention] (1) During dry web creation such as the carding process and airlay process, all spiral crimps are latent with only mechanical crimping, so it is possible to produce a uniform web with the same yield as ordinary polyester cotton. Can be created well.

(2) Creating a web or spun yarn Uniform spiral crimp occurs when brought into contact with water (or steam). This crimp disappears reversibly by drying at room temperature. The spiral crimp is fixed by heat treatment or the like.

(3) Since it is a polyamide/polyester composite fiber of different types of polymers, a bulky product with a high number of crimps and high fastness can be obtained.

1 Example] The present invention will be described below with reference to Examples. The occurrence of crimp in the composite fiber was determined by the number of crimp, and the crimp fastness was determined by the residual crimp ratio. All measurement methods were based on JIS L1015-1981.

1.Number of crimp: Grip both ends of the sample with the grips of the crimp tester, and after applying an initial load of 2 mg/denier, read the number of crimp and the distance between the grips M (mm+) and calculate the number of crimp per 25 mm. demand.

2. Residual crimp rate: Leave the sample in a circulating hot air dryer at 150°C for 5 minutes (free), then take it out, apply a load of 50 mg/denier, and measure the length b after 30 seconds. Next, remove the entire load, leave it for 2 minutes, apply an initial load of 2 mg/denier, and read the length C.

-c Residual crimp rate (%) = X100 (Example 1) [η] (30°C, in m-cresol) 1.17 nylon 6 and [η] (25°C, in 0-chlorophenol) 0.
37 and 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate in an amount of 4.5 copolymerized polyethylene terephthalate as a composite component, a spinning temperature of 285° C. and a spinning speed of 1.
It was pulled at a speed of 100 m/min. The composition of both components was set at a volume ratio of 50:50.

Next, this undrawn yarn was subjected to one-stage and two-stage stretching under the following conditions, and then subjected to tension heat treatment by bringing the tow into contact with seven heating rollers each having a drive system, and the development of spiral crimp was examined. The stretching speed was 90 m/min, and the maximum stretching ratio in the first stage was approximately 3.9, although it varied somewhat depending on the conditions.
It was 5 to 4.06 times. The results are shown in Table 1.

Table 1 No. where spiral crimp did not occur in the above process
, 6 was pushed into a stuffer box with a width of 38 mm and a height of 30 mm, mechanically crimped, placed on a net-like conveyor, and moved for 2 hours while circulating hot air at 35°C. The film was then dried at 100° C. for 1 minute for free shrinkage, and the appearance of crimp was examined. -The results are shown in Table 2.

As shown in Table 2 and above, the composite fibers of the present invention are only mechanically crimped during dry web formation, but are free to shrink afterwards.
It exhibits a unique behavior in that mechanical crimp disappears upon heating, leaving only uniform spiral crimp.

<Example 2) [η] (30°C, H, 17 in nylon 6 in m-cresol) and [η] (25°C, in 0-chlorophenol) 0.4
A composite component containing 4.0 (mol)% of 5-sodium sulfoisophthalic acid based on the acid component of No. 5 and modified polyethylene terephthalate obtained by copolymerizing 5.0 (mol>%) of 1,4-butanediol with respect to the glycol component. Example 1 used as
Composite spinning was carried out in the same manner as above.

Next, this undrawn yarn was drawn in the first step in hot water at 70°C at a maximum draw ratio of 95%, and then in hot water at 85°C at a draw ratio of 0.9
After limited shrinkage to 2 times, the material was finally crimped in a stuffer box in the same manner as in Example 1, and dried on a conveyor net at 35 DEG C. for 2 hours. The number of mechanical crimps of this composite fiber was 26/25 mm, and the number of spiral crimps was O. If you put this thread in water at room temperature (18°C), it will become approximately 31.
Occurrence of spiral crimps was observed at a rate of 25 mm.

This spiral crimp disappeared again after drying at room temperature (23° C.), leaving only mechanical crimp. When the underwater yarn was dried at 100° C. for 10 minutes instead of air drying, only about 39 spiral crimps/25 mm were formed.

Claims (4)

[Claims] (1) A side-by-side polyester component consisting of a modified polyester component copolymerized with 2.0 to 7.0 (mol)% of 5-sodium sulfoisophthalic acid to the acid component and a polyamide component.
Side-type composite fibers with substantially 0 spiral crimps/25 mm under an atmosphere of a temperature of 20 to 30°C and a relative humidity of 40 to 75%, and crimps develop upon contact with water. A polyamide/polyester two-component fiber characterized by: (2) 40-18 in the relaxed state before or after contact with water
The polyamide/polyester bicomponent fiber according to claim 1, wherein the number of mechanical crimps becomes substantially 0/15 mm by dry heat treatment at 0° C., and only spiral crimps appear after cooling. (3) Polyamide and a modified polyester copolymerized with 2.0 to 7.0 (mol)% of 5-sodium sulfoisophthalic acid based on the acid component are composite-spun, and then the maximum drawing ratio of the fiber is 90 to After the first stage stretching at a magnification of 98%,
A method for producing polyamide/polyester two-component fiber, which is characterized by limited shrinkage of 0.85 to 0.98 times in warm water at 80 to 90°C, and further heat treatment at 180 to 200°C under tension. (4) Claim (3) in which mechanical crimps of 8 pieces/25 mm or more are applied after heat treatment at 180 to 200°C under tension.
A method for producing a polyamide/polyester two-component composite fiber as described in .